Artículos de revistas: "Precipitation de ZHS"

1

Na, Moony y Hye Ryung Byon. "Stabilizing Metallic Zn Electrode Using Organic Acid Additives in Aqueous Zinc-Ion Batteries". ECS Meeting Abstracts MA2022-01, n.º 1 (7 de julio de 2022): 20. http://dx.doi.org/10.1149/ma2022-01120mtgabs.

Texto completo

Resumen

Aqueous zinc (Zn)-ion batteries (AZIBs) have been paid attention to as safe, economical, and high-energy-density storages through multiple electron transfer. Although conventional alkaline solution-based AZIBs are primary batteries, recent studies demonstrated the reversible Zn2+ deposition and stripping processes enabled in mildly acidic solutions. It promises the development of rechargeable AZIBs and viable applications for energy storage systems (ESSs). However, metallic Zn employed as the negative electrode has suffered from severe corrosion and precipitation of electrolyte salts in this low pH condition. The Zn electrode undergoes a hydrogen evolution reaction (HER) as Zn2+ is dissolved from the Zn surface. The corrosion leads to a pH rise, precipitating electrolyte salt as zinc hydroxide forms. For example, hexagonal plates of zinc hydroxide sulfate hydrate (Zn4SO4(OH)6∙xH2O, indicated as ZHS) grew on the Zn electrode in 1 M ZnSO4 solution when pH approached ~5.4. The insulating and randomly oriented ZHS increased the surface resistance and caused the non-uniform Zn deposition. These challenges are mitigated by adding organic acid to the 1 M ZnSO4 solution. As the HER raised pH, the acid was promptly deprotonated, then coordinated with Zn2+. This process caused the thin film formation consisting of three-dimensional zinc glutarate. The zinc glutarate protected the Zn electrode and impeded the electrode corrosion and the ZHS precipitation. We demonstrated a uniform Zn plating and stripping process with 10 mM of organic acid in contrast with dendritic and dead Zn growth in the absence of the additive. Galvanostatic tests of symmetric Zn cells revealed over 1000 h cycles with the additives at a current density of 1 mA cm-2 and a limited capacity of 1 mAh cm-2. In contrast, the Zn cells with the additive-free electrolyte solution exhibited 15 times lower cyclability as micron-scale ZHS plates covered the electrode surface. Our strategy using the cheap additives is feasible to use grid-scale ESSs and shows significantly improved cycling performances. I will present details of Zn surface reactions using organic acid additive and corresponding electrochemical performances in this presentation.

Los estilos APA, Harvard, Vancouver, ISO, etc.

2

Xu, Jian Zhong, Ke Hu y Ji Xing Xie. "The Effect of Organic Compounds on the Crystal Structure of Zinc Hydroxystannate". Advanced Materials Research 197-198 (febrero de 2011): 273–76. http://dx.doi.org/10.4028/www.scientific.net/amr.197-198.273.

Texto completo

Resumen

The polyhedral crystals, octahedral crystals and cube crystals of Zinc hydroxystannate (ZHS) were prepared by the homogeneous precipitation synthesis method. The organic compounds, PEG-400, β-cyclodextrin (β-CD) and L-alanine were added in the reaction systems to control the crystal structure. The crystal structure and morphology of products were characterized by SEM and XRD. The crystal structure of all products could be attributed to the cubic ZnSn(OH)6 by the XRD analysis. The SEM pictures of the products were different with the change of organic compounds. The FTIR spectrum indicated the ZHS without organic residual and the possible formation mechanism was discussed.

Los estilos APA, Harvard, Vancouver, ISO, etc.

3

Liu, Cheng, Wenhai Wang, Ashley Black Serra, Vlad Martin Diaconescu, Lorenzo Stievano, Laura Simonelli y Dino Tonti. "Tracking Mn and Zn in Rechargeable Aqueous Zn-MnO2 Batteries By Operando X-Ray Absorption". ECS Meeting Abstracts MA2023-02, n.º 55 (22 de diciembre de 2023): 2705. http://dx.doi.org/10.1149/ma2023-02552705mtgabs.

Texto completo

Resumen

Zn-MnO2 batteries with mildly acidic electrolytes are a promising chemistry for large scale storage thanks to their remarkable energy density, low cost, and high safety. This is mainly obtained thanks to the high capacity of the Zn metal anode, and the nonflammable character of the aqueous electrolyte. MnO2 is one of the most common cathode of choice, not only for being Earth-abundant, but also because it can undergo a two-electron mechanism, which is however complex and still not fully understood. There is currently agreement in considering for discharge a MnO2 dissolution, leading to soluble Mn2+ and simultaneous precipitation of Zinc Hydroxide Sulfate (ZHS, ZnSO4[Zn(OH2)]3·xH2O). When charging the process is not simply reverted. In fact, a distinct electrochemical profile is observed, with at least two distinct plateaus and a third, apparently pseudocapacitive stage (Figure 1a). A similar multistage profile is observed during the second discharge. Although such profile is characteristic and observed with different MnO2 phases and architectures, the underlying mechanism remains elusive, as it seems to involve mainly poorly crystallized phases. We studied the mechanism by operando X-ray absorption (XAS) at the Mn and Zn K-edges to follow speciation simultaneously and quantitatively in the cathode and in the electrolyte via principal component analysis. Beam intensity needed appropriate regulation to avoid interference with the experiment. Simultaneous X-ray diffraction allowed precise correlation with the MnO2 dissolution and ZHS formation. We found evidence of Mn(III) intermediate occurring during local bond reorganization, which is inferred by the significant evolution of the absorption fine structure region (EXAFS) of the Mn K-edge (Figure 1b). In contrast, minor Zn spectral changes reflect primarily processes of precipitation and dissolution, suggesting that no Zn-Mn mixed phases form during cycling. Figure 1

Los estilos APA, Harvard, Vancouver, ISO, etc.

4

Marschilok, Amy C., Esther S. Takeuchi y Kenneth J. Takeuchi. "(Invited) Zinc/ Sodium Vanadium Oxide (NaV₃O₈) Aqueous Electrolyte Batteries: Competing Proton and Zinc Ion Insertion". ECS Meeting Abstracts MA2023-01, n.º 5 (28 de agosto de 2023): 920. http://dx.doi.org/10.1149/ma2023-015920mtgabs.

Texto completo

Resumen

Large-scale energy storage systems suitable for pairing with renewable energy generation require low-cost materials and safety. A promising candidate for large scale storage is the aqueous Zn-ion battery (AZIB). Zinc metal is a useful anode for aqueous batteries as it possesses a high theoretical capacity (820 mAh/g), low redox potential (-0.76 V vs SHE), and allows for two electron transfers per Zn2+ (de)insertion. Sodium vanadium oxides have been investigated as cathode materials for AZIBs as the size of Na+ is larger than Zn2+ facilitating ion diffusion within the lattice. Specifically, sodium vanadium oxide (NaV3O8, NVO) in an anhydrous form and its monohydrate (NaV3O8·H2O) have been identified as candidate materials. Notably, one of the phases that forms during the discharge of these materials within a zinc battery system is zinc hydroxy-sulfate (Zn4(SO4)(OH)6·5H2O (ZHS) and has been attributed to H+ insertion in NVO where the H+ insertion is accompanied by local pH change and precipitation of the ZHS. This presentation probes the competing zinc ion and proton insertion mechanisms for discharge of NVO. The impact of (dis)charge rate on reduction products formed is determined with quantitative Rietveld refinement analysis. Further, synchrotron based EDXRD providing spatio-temporally resolved data is used to determine phase evolution operando in different locations within thick porous NVO positive electrodes. Determining the reaction progression within thick electrodes while under load is an important aspect of scaling batteries appropriately, where these results can have relevance to development of future sustainable energy storage systems.

Los estilos APA, Harvard, Vancouver, ISO, etc.

5

Gou, Yabin, Haonan Chen, Hong Zhu y Lulin Xue. "Microphysical processes of super typhoon Lekima (2019) and their impacts on polarimetric radar remote sensing of precipitation". Atmospheric Chemistry and Physics 23, n.º 4 (22 de febrero de 2023): 2439–63. http://dx.doi.org/10.5194/acp-23-2439-2023.

Texto completo

Resumen

Abstract. The complex precipitation microphysics associated with super typhoon Lekima (2019) and its potential impacts on the consistency of multi-source datasets and radar quantitative precipitation estimation were disentangled using a suite of in situ and remote sensing observations around the waterlogged area in the groove windward slope (GWS) of Yandang Mountain (YDM) and Kuocang Mountain, China. The main findings include the following: (i) the quality control processing for radar and disdrometers, which collect raindrop size distribution (DSD) data, effectively enhances the self-consistency between radar measurements, such as radar reflectivity (ZH), differential reflectivity (ZDR), and the specific differential phase (KDP), as well as the consistency between radar, disdrometers, and gauges. (ii) The microphysical processes, in which breakup overwhelms coalescence in the coalescence–breakup balance of precipitation particles, noticeably make radar measurements prone to be breakup-dominated in radar volume gates, which accounts for the phenomenon where the high number concentration rather than the large size of drops contributes more to a given attenuation-corrected ZH (ZHC) and the significant deviation of attenuation-corrected ZDR (ZDRC) from its expected values (Z^DR) estimated by DSD-simulated ZDR–ZH relationships. (iii) The twin-parameter radar rainfall estimates based on measured ZH (ZHM) and ZDR (ZDRM), and their corrected counterparts ZHC and ZDRC, i.e., R(ZHM, ZDRM) and R(ZHC, ZDRC), both tend to overestimate rainfall around the GWS of YDM, mainly ascribed to the unique microphysical process in which the breakup-dominated small-sized drops above transition to the coalescence-dominated large-sized drops falling near the surface. (iv) The improved performance of R(ZHC, Z^DR) is attributed to the utilization of Z^DR, which equals physically converting breakup-dominated measurements in radar volume gates to their coalescence-dominated counterparts, and this also benefits from the better self-consistency between ZHC, Z^DR, and KDP, as well as their consistency with the surface counterparts.

Los estilos APA, Harvard, Vancouver, ISO, etc.

6

Van Den Broeke, Matthew S., Dana M. Tobin y Matthew R. Kumjian. "Polarimetric Radar Observations of Precipitation Type and Rate from the 2–3 March 2014 Winter Storm in Oklahoma and Arkansas". Weather and Forecasting 31, n.º 4 (7 de julio de 2016): 1179–96. http://dx.doi.org/10.1175/waf-d-16-0011.1.

Texto completo

Resumen

Abstract A powerful winter storm affected the south-central United States in early March 2014, accompanied by elevated convective cells with hail and high rates of sleet, freezing rain, and snow. During portions of the event the thermal profile exhibited a shallow surface cold layer and warm, unstable air aloft. Precipitation falling into the cold layer refroze into ice pellets and was accompanied by a polarimetric refreezing signature and numerous crowdsourced surface ice pellet reports. Quasi-vertical profiles of the polarimetric variables indicated an enhanced reflectivity factor ZHH below the melting layer bright band and enhanced low-level differential reflectivity ZDR values coincident with surface ice pellet reports. Freezing rain rate was highest in areas with high ZHH and specific differential phase KDP values at low levels. High snow rates were most closely associated with 1- and 1.5-km ZHH values, though KDP and ZDR also appeared to show some ability to distinguish high snow rate. Numerous elevated convective cells contained rotating updrafts that appeared to contribute to storm longevity and intensity. Most contained well-defined ZDR maxima or columns and relatively high base-scan ZDR values. Several contained polarimetric signatures consistent with heavy mixed-phase precipitation and hail; social media reports indicated that large hail was produced by some of the storms.

Los estilos APA, Harvard, Vancouver, ISO, etc.

7

Steinert, J. y M. Chandra. "Cloud physical properties and empirical polarimetric measurements of rain signatures at C-Band". Advances in Radio Science 6 (27 de mayo de 2008): 315–18. http://dx.doi.org/10.5194/ars-6-315-2008.

Texto completo

Resumen

Abstract. Raindrops are one type of precipitation in stratiform and convective clouds. To get relationships for describing the raindrops two different methods were used. In the first way, the microphysical properties of the liquid hydrometeors were examined. For this the use of the Rayleigh approximation for small particles (raindrops at C-Band) and the drop size distribution by Ulbrich (Γ-DSD) lead to the calculation of the reflectivity at horizontal polarisation ZHH, the reflectivity at vertical polarisation ZVV and the differential reflectivity ZDR. In the second way, rain signatures were separated from polarimetric measurements. The database of these measurements consists of datasets measured by the dual polarimetric C-Band weather radar POLDIRAD (DLR, Oberpfaffenhofen). The aim of this study was then to combine and to compare the results from the real radar measurements against the theoretical calculations in the ZHH-ZDR plane. Based on these observations and calculations, scientific results for future practical use will be presented in form of empirical equations including ZHH-ZDR. Finally in form of scientific discussion, the ZHH-ZDR plane will be critically assessed for outstanding problems or issues.

Los estilos APA, Harvard, Vancouver, ISO, etc.

8

Afzal, Amina, Nadeem Iqbal y Muhammad Rafique. "Ferrite-SCNTs Composite (ZFS) Embedded Nanostructured Cellulose Acetate Membranes - A Promising Sulphate Salts Rejecting Tool. Synthesis and Characterizations". Journal of Nano Research 80 (5 de septiembre de 2023): 21–36. http://dx.doi.org/10.4028/p-wrtd3s.

Texto completo

Resumen

Tailoring diverse characteristics of nanostructured cellulose acetate (CA) membranes by incorporating nanocomposite-tubes ZFS composed of zinc ferrites decorated over single walled carbon nanotubes (SCNTs) for desalination application, is presented in the current research. In situ coprecipitated route is adopted to synthesize ZFS composite filler that imparts morphological, structural, and thermal modifications in CA membranes. Phase inversion via immersion precipitation route has been adopted to synthesis mixed matrix membranes. Microstructural analysis divulges pore size tuning from 1µm to 5nm by increasing loading content of infused filler (ZFS) from 0 to 4wt.%. XRD and FTIR examinations verified the existence and linkages of impregnated composite nanotubes in the modified membranes. Increasing ZFS contents 1-4wt.% enhanced the thermal stability of host membranes up to 17°C in comparison to pristine CA membranes as proclaimed by thermal degrative investigations. Membranes’ performance is evaluated by deionized water flux and sulphate salts (aluminum and copper) rejection capabilities. The prepared membranes are highly effective in salts removal application as evident from 98% of aluminum sulphate rejection that emanates from micro to nano porosity transformation after increasing filler composite into the membrane matrices.

Los estilos APA, Harvard, Vancouver, ISO, etc.

9

Chang, Wei-Yu, Jothiram Vivekanandan, Kyoko Ikeda y Pay-Liam Lin. "Quantitative Precipitation Estimation of the Epic 2013 Colorado Flood Event: Polarization Radar-Based Variational Scheme". Journal of Applied Meteorology and Climatology 55, n.º 7 (julio de 2016): 1477–95. http://dx.doi.org/10.1175/jamc-d-15-0222.1.

Texto completo

Resumen

AbstractThe accuracy of rain-rate estimation using polarimetric radar measurements has been improved as a result of better characterization of radar measurement quality and rain microphysics. In the literature, a variety of power-law relations between polarimetric radar measurements and rain rate are described because of the dynamic or varying nature of rain microphysics. A variational technique that concurrently takes into account radar observational error and dynamically varying rain microphysics is proposed in this study. Rain-rate estimation using the variational algorithm that uses event-based observational error and background rain climatological values is evaluated using observing system simulation experiments (OSSE), and its performance is demonstrated in the case of an epic Colorado flood event. The rain event occurred between 11 and 12 September 2013. The results from OSSE show that the variational algorithm with event-based observational error consistently estimates more accurate rain rate than does the “R(ZHH, ZDR)” power-law algorithm. On the contrary, the usage of ad hoc or improper observational error degrades the performance of the variational method. Furthermore, the variational algorithm is less sensitive to the observational error of differential reflectivity ZDR than is the R(ZHH, ZDR) algorithm. The variational quantitative precipitation estimation (QPE) retrieved more accurate rainfall estimation than did the power-law dual-polarization QPE in this particular event, despite the fact that both algorithms used the same dual-polarization radar measurements from the Next Generation Weather Radar (NEXRAD).

Los estilos APA, Harvard, Vancouver, ISO, etc.

10

Van Den Broeke, Matthew S., Jerry M. Straka y Erik N. Rasmussen. "Polarimetric Radar Observations at Low Levels during Tornado Life Cycles in a Small Sample of Classic Southern Plains Supercells*". Journal of Applied Meteorology and Climatology 47, n.º 4 (1 de abril de 2008): 1232–47. http://dx.doi.org/10.1175/2007jamc1714.1.

Texto completo

Resumen

Abstract Preliminary schematics of polarimetric signatures at low levels in southern plains classic supercells are developed for pretornado, tornado, and tornado demise times from a small collection of cases, most of which are cyclic tornado producers. Characteristic signatures and patterns are identified for the reflectivity factor (ZHH), the differential reflectivity (ZDR), the correlation coefficient (ρhv), and the specific differential phase (KDP). Signatures likely related to an ongoing tornado are also discussed. Major findings in ZHH at tornado times include “wings” of higher values often extending away from the updraft region, a stronger gradient on the west side of the echo appendage, and a local maximum at the storm location favorable for tornadogenesis. Increasing cyclonic curvature of the hook-echo region was noted through the tornado life cycle. The ZDR tended to indicate hail shafts most commonly at tornado times, with the highest storm values typically located along the storm’s forward flank throughout the tornado life cycle. A ZDR minimum often occurred at the tornado-favorable location, while low ZDR occasionally trailed the tornado region. Storm-minimum ρhv typically occurred at the tornado-favorable location at tornado times and in hail shafts or heavy rain areas at other times. Another region of low correlation was the storm updraft, while the highest storm correlation was typically found in the downwind light-precipitation shield. The KDP typically exhibited a storm-core temporal maximum at tornado times, with the highest storm values in regions of hail and heavy rain and the lowest values in the downwind light-precipitation region. Values in the tornado-favorable region were typically near zero and sometimes strongly negative.

Los estilos APA, Harvard, Vancouver, ISO, etc.

11

Paek, Seung-Min, Won-Young Jo, Man Park y Jin-Ho Choy. "Time-Dependent X-ray Absorption Spectroscopic (XAS) Study on the Transformation of Zinc Basic Salt into Bis(N-oxopyridine-2-thionato) Zinc (II)". Journal of Nanoscience and Nanotechnology 7, n.º 11 (1 de noviembre de 2007): 3867–71. http://dx.doi.org/10.1166/jnn.2007.060.

Texto completo

Resumen

Solid transchelation reaction was established for the synthesis of bis(N-oxopyridine-2-thionato) zinc (II), commonly known as zinc pyrithione (ZPT), to control particle size using zinc basic salt (ZBS) and aqueous sodium pyrithione solution. Distinguished from ZPT particles prepared by usual precipitation reaction, the obtained ZPT nanoparticles exhibited very narrow size distribution. X-ray absorption spectroscopy (XAS) at Zn K-edge was systematically examined to elucidate time-dependent local structural evolution during solid transchelation reaction. X-ray absorption near edge structure (XANES) analysis clearly revealed that local environment around zinc atoms transformed into pentahedron as reaction proceeded. Based on quantitative X-ray diffraction and XANES analysis, we made structural models. Theoretical XAS spectrum calculated with FEFF code could reproduce experimental one, suggesting that XAS analysis could be very powerful tool to probe phase transformation. Furthermore, according to extended X-ray absorption fine structure (EXAFS) fitting results, Zn-O distance in reaction products gradually increased from 1.96 to 2.07 Å, suggesting that zinc atoms bounded with oxygen ones in ZBS were transchelated with pyrithione ligands. This study could be a strong evidence for the usefulness of XAS to study time-dependent structural transformation of nanocrystalline materials.

Los estilos APA, Harvard, Vancouver, ISO, etc.

12

Maskaeva, Larisa N., Anna I. Zhdanova, Vyacheslav F. Markov y Anastasia D. Kutyavina. "Chemical bath synthesis of metal chalcogenide films. Part 40. Influence of hydrochemical deposition conditions of ZnS films by thioacetamide on their thickness and morphology". Butlerov Communications 57, n.º 3 (31 de marzo de 2019): 139–48. http://dx.doi.org/10.37952/roi-jbc-01/19-57-3-139.

Texto completo

Resumen

ZnS thin films are promising as a buffer layer in solar cells; photovoltaic cells, photoelectric sensors, light-emitting diodes are being developed on their basis. In this work, the growth kinetics of ZnS films has been studied during hydrochemical precipitation with thioacetamide from acidic (biphthalate, acetate) and alkaline (ammonia) aqueous solutions. From the biphthalate bath at pH = 2.5–3.0 at 343 K and from the ammonia reaction mixture at 293 K on glass substrates, mirror layers of zinc sulfide with a thickness of up to 250 and 330 nm were obtained, respectively. The maximum thickness of the ZnS films from the ammonia system is achieved by increasing the ammonia content in it to 5 mol/l. For all the ammonia concentrations used, an extreme dependence of the thickness of the ZnS films on the concentration of thioacetamide in the system was established. When precipitating ZnS films from the acetate system, lowering the pH of the solution from 5.0 to 4.5 increases their thickness by a factor of 1.5-2.0. On the kinetic curves of changes in the thickness of the ZnS films during deposition from the biphthalate system, an area is distinguished, which is characterized by the presence of a plateau, which presumably corresponds to the sulfidization process of the zinc hydroxide phase formed at the initial stage of synthesis. The optimal composition of the reaction mixtures and the recommended time of deposition of ZnS films from the studied reaction mixtures are proposed. According to electron microscopy, the main structural elements of the zinc sulfide films precipitated with thioacetamide, regardless of the composition of the reaction mixture, are globular aggregates. The layers precipitated from the biphthalate reaction mixture have more uniform microstructure with a predominant particle size of 30-50 nm. Films obtained from the ammonia reaction mixture are formed from globules with a diameter of from 0.5 to 5.0 μm with particles of ~ 100 nm interspersed. The content of the main elements (Zn, S) in the ZnS films obtained from the biphthalate and ammonia reaction mixtures, according to the data of energy dispersive microanalysis, was 49.48, 50.52 and 50.35, 49.65 at.%, respectively.

Los estilos APA, Harvard, Vancouver, ISO, etc.

13

Chen, Ju-Yu, Wei-Yu Chang y Pao-Liang Chang. "A Synthetic Quantitative Precipitation Estimation by Integrating S- and C-Band Dual-Polarization Radars over Northern Taiwan". Remote Sensing 13, n.º 1 (5 de enero de 2021): 154. http://dx.doi.org/10.3390/rs13010154.

Texto completo

Resumen

The key factors, namely, the radar data quality, raindrop size distribution (RSD) variability, and the data integration method, which significantly affect radar-based quantitative precipitation estimation (QPE) are investigated using the RCWF (S-band) and NCU C-POL (C-band) dual-polarization radars in northern Taiwan. The radar data quality control (QC) procedures, including the corrections of attenuation, the systematic bias, and the wet-radome effect, have large impact on the QPE accuracy. With the proper QC procedures, the values of normalized root mean square error (NRMSE) decrease about 10~40% for R(ZHH) and about 5~15% for R(KDP). The QPE error from the RSD variability is mitigated by applying seasonal coefficients derived from eight-year disdrometer data. Instead of using discrete QPEs (D-QPE) from one radar, the synthetic QPEs are derived via discretely combined QPEs (DC-QPE) from S- and C-band radars. The improvements in DC-QPE compared to D-QPE are about 1.5–7.0% and 3.5–8.5% in R(KDP) and R(KDP, ZDR), respectively. A novel algorithm, Lagrangian-evolution adjustment (LEA), is proposed to compensate D-QPE from a single radar. The LEA-QPE shows 1–4% improvements in R(KDP, ZDR) at the C-band radar, which has a larger scanning temporal gap (up to 10 min). The synthetic LEA-QPEs by combining two radars have outperformed both D-QPEs and DC-QPEs.

Los estilos APA, Harvard, Vancouver, ISO, etc.

14

Sun, Li, Zhiwen Li, Yougui Song, Hongyi Zhou, Qingbin Fan, Wubiao Li y Ni Tang. "Grain Size Characteristics of MIS 5 Sediments and Evolution of the East Asian Summer Monsoon in the Zhifu Section, Yantai City, Shandong Province, China". Atmosphere 14, n.º 1 (10 de enero de 2023): 153. http://dx.doi.org/10.3390/atmos14010153.

Texto completo

Resumen

The North Yellow Sea, located at the intersection of the Eurasian continent and North Pacific Ocean at mid-latitudes, is a sensitive area subjected to the joint actions of the ocean, land, and monsoons. On its southern shore, loess and paleosol sedimentary sequences were widely developed during the last interglacial period, which is of great significance for revealing patterns of climate change and dynamic conditions. In this paper, we focus on the Zhifu section (ZFS) on Zhifu Island within the Shandong Province of China. The optically stimulated luminescence (OSL) dating method was used to construct our chronological framework. Grain size and its endmember (EM) components were then analyzed; EM1 is a clay component EM, which represents a weak dynamic environment and strong weathering pedogenesis, while EM2 and EM3 are silt and very fine sand component EMs, respectively, representing a strong dynamic environment and weak weathering pedogenesis. Maximum EM1, mean grain size, clay content, and pH values occur in the paleosol layers (ZF4, ZF6, and ZF8), with minimum values in the loess layers (ZF5 and ZF7); EM3 values show the opposite pattern. This indicates that the ZF4, ZF6, and ZF8 layers represent warm and humid environments with abundant precipitation, where the East Asian summer monsoon (EASM) was enhanced, corresponding to Marine Isotope Stages (MIS) 5a, 5c, and 5e. In contrast, ZF5 and ZF7 represent sub-warm and humid environments with less precipitation, where the EASM was weakened, corresponding to MIS 5b and 5d. Among these stages, MIS5e is the warmest and wettest. These climatic events reveal the pattern of climate fluctuation over a ten-thousand-year timescale; they are synchronous with climate changes recorded in other geological repositories, such as cave stalagmites in southern China and sea-level fluctuations in the Yellow-Bohai Sea, which result from changes in global solar radiation.

Los estilos APA, Harvard, Vancouver, ISO, etc.

15

MA, Yining. "A dataset of daily water consumption records for maize at Shiyanghe Experimental Station of China Agricultural University during 2009-2016". China Scientific Data 8, n.º 4 (31 de diciembre de 2023): 1–5. http://dx.doi.org/10.11922/11-6035.csd.2022.0091.zh.

Texto completo

Resumen

A good understanding of the variation in crop water consumption in farming systems is essential for studying the patterns of water consumption by crops at various growth stages. Based on this, this dataset provides the maize evaporation and precipitation intensity data measured by a large-scale lysimeter at Shiyanghe Experimental Station of China Agricultural University from 2009 to 2016, with a temporal resolution of daily scale. The irrigation method is border irrigation. The data acquisition and processing process strictly follows the instrumental data quality control and specifications. After data processing, quality control and evaluation, the data are made public on a daily scale with a view to providing a basis for the efficient use of regional agricultural water resources.

Los estilos APA, Harvard, Vancouver, ISO, etc.

16

Li, Chaokui, Rui Zhang, Ting Li, Haibin Guo y Ruirong Guo. "Dynamic Changes and Influencing Factors of Vegetation in the “Green Heart” Zone of the Chang-Zhu-Tan Urban Agglomeration during the Past 21 Years". International Journal of Environmental Research and Public Health 20, n.º 5 (3 de marzo de 2023): 4517. http://dx.doi.org/10.3390/ijerph20054517.

Texto completo

Resumen

As a policy, protected green space in the rapidly developing the Chang-Zhu-Tan Urban Agglomeration is of great practical significance to study the vegetation changes and influencing factors in the Green Heart area. In this paper, data processing, grading and area statistics were carried out for the maximum value of normalized differential vegetation index (NDVI) from 2000 to 2020. Combined with Theil–Sen median trend analysis and Mann–Kendall, the change trend of long-time series NDVI was studied, and investigation of NDVI influencing factors, processes and mechanisms using geographical detectors. The results showed that: (1) The spatial distribution characteristics of NDVI in the study area were high in the middle and inlaid transition between adjacent grades. Except for the low grades, the distribution of NDVI in other grades was relatively scattered, and the overall trend of NDVI change was rising. (2) Population density was the main factor affecting NDVI changes, with an explanatory power of up to 40%, followed by elevation, precipitation and minimum temperature. (3) The influence of influencing factors on the change of NDVI was not the result of independent action of a single factor, but the result of the interaction between human factors and natural factors, and the factor combinations with greater interaction had significant differences in the spatial distribution of NDVI.

Los estilos APA, Harvard, Vancouver, ISO, etc.

17

Li, Tang, Cunyou Chen, Qizhen Li, Luyun Liu, Zhiyuan Wang, Xijun Hu y Saroj Thapa. "Evolution Characteristics of Landscape Patterns and the Response of Surface Runoff in a Rapid Urbanization Area: Focus on the Chang–Zhu–Tan Metropolitan Area of China". Water 15, n.º 19 (30 de septiembre de 2023): 3467. http://dx.doi.org/10.3390/w15193467.

Texto completo

Resumen

With the acceleration of urbanization, the disturbance to urban landscape patterns causes changes to urban surface runoff and increases the risk of urban waterlogging. We studied the response relationship between landscape pattern change and surface runoff in the Chang–Zhu–Tan metropolitan area for the period from 2000 to 2020, analyzing the driving factors that affected surface runoff. The influence of landscape pattern evolution on surface runoff was studied using the SCS-CN flow generation model, the moving window method, and Pearson’s analysis. The analysis showed that between 2000 and 2020, the forest area decreased, while the impermeable land area increased substantially. At the same time, the landscape spread degree (CONTAG) decreased, whereas the landscape fragmentation degree (DIVISION) increased, and the Shannon diversity index (SHDI) and landscape shape index (LSI) increased. The surface runoff in the main urban areas of Chang–Zhu–Tan increased substantially. The results showed that surface runoff is negatively correlated with SHDI, LSI, and DIVISION but displays a positive relationship to CONTAG. Soil texture and precipitation had the greatest impact on surface runoff. This study emphasizes the importance of landscape pattern evolution to surface runoff in rapidly developing metropolitan areas in terms of reducing surface runoff, alleviating urban waterlogging and preventing regional floods. Our research additionally seeks to optimize the landscape pattern of the Chang–Zhu–Tan metropolitan area.

Los estilos APA, Harvard, Vancouver, ISO, etc.

18

XU, Ziwei. "A dataset of water vapor-heat-carbon fluxes and meteorological observations in croplands of Hai River Basin from 2013 to 2020". China Scientific Data 9, n.º 1 (31 de marzo de 2024): 1–5. http://dx.doi.org/10.11922/11-6035.csd.2023.0168.zh.

Texto completo

Resumen

The present study area was located in the cropland ecosystem near Guanting Reservoir in Haihe River Basin. We conducted long-term observations of the multi-scale fluxes and meteorological elements, using various observation systems, including lysimeter, eddy covariance, large aperture scintillometer and automatic weather station/gradient of meteorological elements. This dataset consists of multi-scale fluxes (meter, hundred-meter, and kilometer-meter) and meteorological elements data. Observation items include ecosystem net carbon exchange, latent heat flux/evapotranspiration, sensible heat flux, air temperature, relative humidity, wind speed, wind direction, downward/upward shortwave radiation, downward/upward longwave radiation, net radiation, atmospheric pressure, precipitation, infrared radiation temperature, photosynthetic effective radiation, soil temperature, soil moisture, soil heat flux, and average soil temperature, etc. This dataset is processed carefully and can be used to study the effects of reservoir expansion and shrinkage on the circulation of carbon and water or other substances in the surrounding ecosystem. Additionally, it can serve as a powerful data basis for the research on relevant remote sensing estimation and model simulation.

Los estilos APA, Harvard, Vancouver, ISO, etc.

19

TANG, Xuguang. "A dataset of carbon and water fluxes observations in subtropical evergreen broad-leaved forest in Jinfo Mountain from 2020 to 2021". China Scientific Data 8, n.º 4 (31 de diciembre de 2023): 1–5. http://dx.doi.org/10.11922/11-6035.csd.2023.0103.zh.

Texto completo

Resumen

Chongqing Jinfo Mountain Karst Ecosystem National Observation and Research Station was officially included in the construction list of the selected national field stations in December, 2020 by China’s Ministry of Science and Technology. In its main observation field, based on the eddy covariance technique, long-term and continuous measurements of carbon and water fluxes in the subtropical evergreen broad-leaved forest ecosystem has been carried out since three years ago. Using the flux data processing system of ChinaFLUX, we conducted the strict work of data quality control and evaluation and obtained the standard dataset of carbon and water fluxes and the key meteorological data in the subtropical evergreen broad-leaved forest ecosystem at the Jinfo Station from 2020 to 2021. The dataset was comprised of net ecosystem carbon exchange, gross primary productivity, ecosystem respiration, latent heat, sensible heat, as well as air temperature/humidity, wind speed/direction, soil temperature/humidity, precipitation, downwelling shortwave radiation, net radiation and photosynthetically active radiation. This dataset can provide significant data support for analyzing the carbon source/sink of typical forest ecosystems, exploring the coupling relation between carbon and water cycles, as well as their response mechanisms to global climate change.

Los estilos APA, Harvard, Vancouver, ISO, etc.

20

TAN, Zhaowei. "A dataset of daily meteorological elements of the Guangdong Nanling Forest Ecosystem National Field Scientific Observation and Research Station during 2021–2022". China Scientific Data 9, n.º 1 (31 de marzo de 2024): 1–5. http://dx.doi.org/10.11922/11-6035.csd.2023.0123.zh.

Texto completo

Resumen

The mountainous forest and biodiversity ecological functional area of the Nanling Mountain forest ecosystem is one of the 25 key ecological functional areas in China, covering a variety of forest vegetation types, including tropical and subtropical moist broadleaf forests, coniferous broad-leaved evergreen mixed forest, and mountain top evergreen broad-leaved dwarf forest. The tropical and subtropical moist broadleaf forests are the most typical vegetation type in the Nanling Mountains. Monitoring the meteorological elements in the community can help understand the response mechanism of the tropical and subtropical moist broadleaf forests in the Nanling Mountains to climate change. Based on the Nanling Forest Ecosystem National Field Scientific Observation Research station ("Nanling Station" for short) in the Nanling Mountains, Guangdong, we carried out positioning research in Nanling National Nature Reserve. In this paper, we disclosed the raw data of 10 min average wind speed, precipitation, air temperature, air pressure, solar radiation (i.e. total radiation, reflected radiation, ultraviolet radiation, net radiation, photosynthetically active radiation) as well as relative humidity continuously collected in the subtropical evergreen broad-leaved forest area of the Nanling Station from 2021-2022 on a daily scale after data processing, quality control and evaluation. The dataset accessible to the public can serve as a valuable resource for further insights into the Nanling Mountain Forest Ecosystem, and provide foundation for efforts related to the restoration and protection of forest ecosystems.

Los estilos APA, Harvard, Vancouver, ISO, etc.

21

CAO, Yongqiang. "A dataset of gradient meteorological observations at Sichuan Zoige Alpine Wetland Station in 2022". China Scientific Data 8, n.º 4 (31 de diciembre de 2023): 1–5. http://dx.doi.org/10.11922/11-6035.csd.2023.0100.zh.

Texto completo

Resumen

Meteorological factors are one of the important elements for field observation at the Chinese Ecosystem Research Network (CERN) positioning stations, which can provide basic data for the research on ecosystem and global change, and weather forecasting. Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station (referred to as "Zoige Station") stand as the sole newly-approved domestic alpine wetland ecological station. In 2021, Zoige Station built the vertical gradient observation of meteorological elements, which is of great significance for revealing the meteorological characteristics and the ecological protection of the alpine wetlands of Zoige Plateau. We used the Zoige Station's vertical gradient automatic meteorological observation system to ensure consistency and accuracy of the data by following the standard and specifications of the Ground Meteorological Observation Specification, and eliminating invalid data according to the relevant rules of the Ecological System Atmospheric Environment Observation Specification. We then interpolated missing data to ensure data integrity. Specifically, we compiled 24 meteorological indexes totaling 8,760 entries of daily scale data of the gradient meteorological observations at Zoige Station in 2022, including atmospheric pressure, precipitation, total radiation, photosynthetic effective radiation at 2 m above ground, air temperature, relative humidity, wind speed at the heights of 2 m, 6 m, 12 m, 16 m, and 20 m above ground, as well as soil temperature at the depths of 20 cm, 40 cm, 60 cm, 100 cm, and 150 cm. This dataset can provide data support for the ecological environment protection of Zoige Plateauand, reveal the rules of atmospheric environment changing, and scientific research on the plateau.

Los estilos APA, Harvard, Vancouver, ISO, etc.

22

HE, Fuquan. "A dataset of carbon, water and heat fluxes over an Elymus nutans artificial grassland in the Sanjiangyuan Area (2012–2016)". China Scientific Data 8, n.º 4 (31 de diciembre de 2023): 1–5. http://dx.doi.org/10.11922/11-6035.csd.2023.0056.zh.

Texto completo

Resumen

In the Sanjiangyuan Area known as the “Chinese Water Tower”, planting perennial artificial grassland has become an important measure for the restoration of degraded grassland in this area. The spatial-temporal pattern of the carbon, water, and heat fluxes of Elymus nutans artificial grasslands are crucial for comprehending the ecological service functions of the Elymus nutans artificial grasslands in the Sanjiangyuan Area. Sanjiangyuan Grassland Ecosystem National Observation and Research Station (referred to as Sanjiangyuan Sation) has used the eddy covariance technique to monitor the carbon, water, and heat fluxes over an Elymus nutans artificial grassland for 5 years since 2009. In order to advance the research on carbon, water, and heat fluxes and other related researches in the Sanjiangyuan Area and the broader Qinghai-Tibetan Plateau alpine ecosystems, we plan to publish the routine meteorological data of carbon, water and heat fluxes over an Elymus nutans artificial grassland observed from 2012 to 2016. This dataset includes routine meteorological data (i.e. air temperature, air relative humidity, water vapor pressure, soil temperature, soil moisture, photosynthetically active radiation, and precipitation) and carbon, water, and heat fluxes data (net ecosystem CO2 exchange, ecosystem CO2 respiration, gross ecosystem CO2 exchange, latent heat flux, and sensible heat flux) on half-hourly, daily, monthly, and yearly scales. The dataset used the flux data processing method recommended by ChinaFLUX. It is expected to provide field observational data support for scientific understanding, remote sensing retrieval processes, and model validation efforts in exploring the spatiotemporal patterns of carbon, water, and heat exchanges in artificial Elymus nutans grasslands.

Los estilos APA, Harvard, Vancouver, ISO, etc.

23

LIU, Weiwei. "A dataset of daily meteorological observations of Lijiang Forest Biodiversity National Observation and Research Station during 2013-2022". China Scientific Data 8, n.º 4 (31 de diciembre de 2023): 1–5. http://dx.doi.org/10.11922/11-6035.csd.2023.0121.zh.

Texto completo

Resumen

Meteorological factors are important environmental elements of field positioning observation stations of CNERN, CERN and CFERN. The acquisition of high-quality observational data through long-term positioning observations is beneficial for advancing our scientific understanding of ecosystem processes and tracking dynamic changes in biodiversity. It also provides important support for the development of regional and national ecological, environmental, and resource security construction initiatives. As one of the Forest Biodiversity National Observation and Research Stations approved in 2021, Lijiang Station has been collecting data in accordance with the CERN meteorological monitoring standards for past consecutive years. Up to now, Lijiang Station has consistently maintained comprehensive data parameters, a structured approach, and a high level of data standardization. These data can serve as important foundation for various research endeavors, including dynamic changes in the structure, processes, and functions of regional forest ecosystems, the formation, evolution, and preservation of regional biodiversity mechanisms, forest biodiversity and ecosystem functioning, the monitoring, evaluation, and conservation of biodiversity for key wild protected species, and the assessment and innovative exploitation of distinctive biological resources. This dataset comprises 3,652 entries and 39 fields of daily meteorological data spanning from 2013 to 2022. It covers atmospheric elements (air temperature and humidity, atmospheric pressure, wind speed and direction, precipitation, radiation elements) and soil elements (soil stratified temperature and soil heat flux). The release of the dataset offers comprehensive fundamental meteorological data for scientific research in related fields and provides essential data support for local and large-scale networking research.

Los estilos APA, Harvard, Vancouver, ISO, etc.

24

Zhao, Yifei, Xinqing Zou, Jianhua Gao y Chenglong Wang. "Recent sedimentary record of storms and floods within the estuarine-inner shelf region of the East China Sea". Holocene 27, n.º 3 (28 de julio de 2016): 439–49. http://dx.doi.org/10.1177/0959683616660165.

Texto completo

Resumen

Although extreme weather events make a strong impact in shallow marine sedimentary environments, there is still a paucity of past records for the Holocene period. Estuarine-inner shelf mud regions deposited from rivers that transport a large amount of suspended sediment represent an important archive of the Holocene. Two cores (S5-2 and JC07) retrieved from the estuarine-inner shelf regions of the East China Sea provided an opportunity to use sensitive grain size and 210Pb dating to reconstruct a history of extreme weather events in the Yangtze River basin. Here, we show that the average sedimentation rates of the two cores, S5-2 (1930–2013) and JC07 (1910–2013), were estimated to be 3.11 and 1.56 cm/yr, respectively. The results indicated that sediment supply played an important role in sedimentation of the estuarine-inner shelf mud region of the East China Sea. Sand content strongly increased in the late 1980s, a result of downstream riverbed erosion of the Yangtze River and submerged deltas. The grain size versus the standard deviation method was used to identify grain-size intervals with the highest variability along a sedimentary sequence. The Yangtze estuary mud area coarse population correlated well with historical literature on Yangtze River floods since AD 1930. Extreme storm events corresponded well with historical literature on the Zhe-Min mud region of the East China Sea. The spectral analyses of the sample core coastal population demonstrated that flood and storm events were consistent with a ~3–8 a periodic change of El Niño Southern Oscillation (ENSO), suggesting that the flood events usually follow ENSO years in the Yangtze River. Consequently, sediment records preserved in the two cores demonstrated different sedimentary responses to Yangtze River floods and storms, which is important to recover centennial scale flood events, to infer extreme precipitation, and to understand climate change in the estuarine-inner shelf of the East China Sea. Nevertheless, more efforts are still needed to simulate paleo-flood and predict future flood events in the context of global warming.

Los estilos APA, Harvard, Vancouver, ISO, etc.

25

HUANG, Hui. "A dataset of carbon and water flux observations in a Quercus variabilis plantation in Xiaolangdi (2016–2017)". China Scientific Data 8, n.º 4 (31 de diciembre de 2023): 1–5. http://dx.doi.org/10.11922/11-6035.csd.2023.0082.zh.

Texto completo

Resumen

The concern about global change has brought more attention to the role of plantations in the regional carbon and water cycle recently. Quercus variabilis is one of the most widely distributed natural tree species in China. The southern foot of Taihang Mountain is one of the key areas of forestry engineering in China. The study on the observation of water and carbon fluxes in a Quercus variabilis plantation in this area is of great significance to the development of forestry ecological engineering and the evaluation of plantation carbon sink function in China. Henan Xiaolangdi Earth Critical Zone National Research Station on the Middle Yellow River (i.e. XLD) has carried out long-term observation of and research on the carbon and water fluxes in a Quercus variabilis plantation using the eddy covariance technique since 2005. This dataset contains carbon and water flux observations and meteorological data collected from XLD from 2016 to 2017, which have been processed in accordance with the standard quality control system of ChinaFLUX. It covers the data of gross ecosystem primary productivity, ecosystem respiration, net ecosystem carbon exchange, latent heat flux, sensible heat flux and other related meteorological factors, such as air temperature, air relative humidity, vapor pressure, wind speed, wind direction, radiation, soil temperature, soil moisture, precipitation, etc. The dataset is composed of the data collected at the scales of half-hourly, daily, monthly, and yearly intervals. This dataset can provide data support for the management of plantation ecosystems and the assessment of regional carbon budgets. Moreover, it plays a crucial role in promoting data sharing and standardization management of field stations in China.

Los estilos APA, Harvard, Vancouver, ISO, etc.

26

QU, Lisha, Qiuan ZHU, Chaofan ZHU y Jiang ZHANG. "A dataset of monthly precipitation with resolution of 1 km in China from 1960 to 2020". China Scientific Data 8, n.º 2 (30 de junio de 2023). http://dx.doi.org/10.11922/11-6035.csd.2022.0024.zh.

Texto completo

Resumen

Precipitation data are greatly valuable in theoretical research and practical application, and have been widely used in hydrological forecasting, agricultural production, ecological protection and other fields. China has a vast territory with large topographic fluctuations, and most meteorological stations are located in densely populated plain areas. Due to the low density of stations, there is a lack of precipitation observation data in some areas such as mountainous areas. Therefore, it is necessary to use the interpolation method to establish high-precision precipitation datasets. Based on the precipitation monitoring data from more than 2,400 meteorological stations on the ground from 1960 to 2020, we used the climate data spatial interpolation software ANUSPLIN to obtain a dataset of monthly precipitation interpolation with a resolution of 1 km in China. According to the comparison between the dataset and the measured precipitation data as well as the hydrological yearbook data in China released by the CRU and Northwest University of agriculture and forestry science and technology, this dataset has the characteristics of high accuracy, high resolution and long time series, with great potential in scientific research and application.

Los estilos APA, Harvard, Vancouver, ISO, etc.

27

TAN, Xingru, Bingwei ZHANG y Shiping CHEN. "A dataset of observational key parameters in carbon and water fluxes in a semi-arid steppe, Inner Mongolia (2012 – 2020): based on a long-term manipulative experiment of precipitation pattern". China Scientific Data 8, n.º 2 (30 de junio de 2023). http://dx.doi.org/10.11922/11-6035.csd.2023.0052.zh.

Texto completo

Resumen

Warming has led to remarkable changes in global precipitation pattern, which will significantly affect vegetation growth and ecosystem function of the semiarid grasslands in Northern China. As a key processe of ecosystem function, carbon and water flux determines the carbon sequestration capability and resource utilization strategies of ecosystems. Therefore, understanding the responses of ecosystem carbon and water fluxes to precipitation pattern changes and their controls will be helpful for the evaluation in the carbon sequestration capacity of grassland ecosystems. However, there is a lack of long-term experiments and observational data on the responses of carbon and water processes to precipitation pattern changes in grassland ecosystems. Based on the long-term precipitation pattern manipulative experiment (including seven precipitation amount and rain event frequency treatments), we collected seasonal dynamics of ecosystem carbon and water fluxes by the static chamber method connecting with infrared gas analyzer during 2012-2020 in Xilin Gol grassland, Inner Mongolia. The dataset consists of two data files, namely the meteorological environmental data file (including annual precipitation, air temperature, soil moisture, and soil temperature) and the carbon and water fluxes data file (including ecosystem gross primary productivity, ecosystem respiration, net ecosystem carbon exchange, evapotranspiration, carbon use efficiency, and water use efficiency). Preliminary data analysis has shown that the drought treatment could significantly reduce the carbon and water fluxes, while water addition treatment had no significant effect on them. All the parameters recovered to the control level in the first year after the treatment cessation. This dataset is expected to provide important data support for the understanding of the responses of carbon and water cycles and their coupling processes to future precipitation regime in grasslands of Northern China.

Los estilos APA, Harvard, Vancouver, ISO, etc.

28

WEN, Huayang, Fengjiao CHEN, Kangjun QIU y Hualiang ZHU. "A dataset of gridded hourly precipitation at 1 km resolution over Anhui Province during 2008 – 2018". China Scientific Data 7, n.º 3 (30 de septiembre de 2022). http://dx.doi.org/10.11922/csdata.2021.0003.zh.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

29

WU, Xingqi, Qi CHENG, Linfeng WEI, Xiaofei HU y Jian NI. "A dataset of time series of climate variables in the karst areas of Southwest China from 1951 to 2014". China Scientific Data 7, n.º 4 (31 de diciembre de 2022). http://dx.doi.org/10.11922/11-6035.csd.2022.0004.zh.

Texto completo

Resumen

The areas with karst topography in Southwest China have a fragile ecological environment and the ecosystem there is vulnerable to climate change and human activities. Due to the influence of the karst topography, the spatial distribution of weather stations in this area is uneven which, together with the slight difference of meteorological observation time series of each observation station and the limited number of stations, makes it difficult for the observed data to be used in the study on the realationship between terrestrial ecosystems and climate change. In this study, we used the local smooth thin plate spline function from the ANUSPLIN software version 4.3, combining with the Shuttle Radar Topography Mission (SRTM) digital elevation model, to spatially interpolate four monthly climatic variables (i.e. temperature, precipitation, sunshine percentage, and wet days with daily precipitation <0.1 mm). In this way, we finally obtained three sets of gridded data in different formats with a resolution of 1km. The error statistics show that the error of the interpolation results is relatively low, especially with a high accuracy of the temperature interpolation. The gridded data of the four climate variables can truly reflect the spatial distribution of climates in the karst areas. Further analyses show that from 1951 to 2014, the distribution of temperature and precipitation showed a decreasing trend from the southeast to the northwest. The overall change of temperature showed an upward trend, and the change trend of precipitation was not significant. The distribution of sunshine percentage gradually decreased from the middle to the two sides, and the sunshine percentage showed an overall decline trend. The distribution patterns of wet days are inversely related to altitudes. This dataset can provide data support for the regional research on climate, the relationship between vegetation, rocky desertification and climate change, the relationship between land use and land cover changes, as well as the climate–driven terrestrial ecological model simulations.

Los estilos APA, Harvard, Vancouver, ISO, etc.

30

WEI, Peigang, Fantao KONG, Lin HU, Shanshan CAO y Wei SUN. "A dataset of ecological factors in the distribution area of Tianshan spruce in Yili region in 2014". China Scientific Data 8, n.º 1 (31 de marzo de 2023). http://dx.doi.org/10.11922/11-6035.nasdc.2022.0014.zh.

Texto completo

Resumen

Tianshan spruce (Picea schrenkiana var. tianschanica ) is an important tree for water conservation, windbreak and sand fixation in the mountains of Xinjiang, and plays an important role in the formation and maintenance of forest ecosystem in Xinjiang. Ecological factors such as temperature, precipitation, soil and topography are important data bases for studying forest ecosystem. Based on multi-source data such as remote sensing image, DEM, meteorological data and soil data in Yili region of Xinjiang, we used multi-scale segmentation, nearest neighbor classification and spatial analysis to generate a dataset of ecological factors in the distribution area of Tianshan spruce in Yili region in 2014, covering six ecological factors, namely temperature, precipitation, sunshine duration, slope, slope direction and soil type. In this dataset, strict procedures of data quality control were carried out by TTA Mask accuracy verification and other methods to ensure the accuracy and reliability of the data. The dataset can provide data support for forest ecosystem health assessment.

Los estilos APA, Harvard, Vancouver, ISO, etc.

31

"A dataset of rainstorm in China based on GPM precipitation product during 2001–2019". China Scientific Data 7, n.º 2 (30 de junio de 2022). http://dx.doi.org/10.11922/11-6035.csd.2021.0050.zh.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

32

Li, Jing, Ruirui Ge, Feng Wang, Jinfan Gu, Mengyu Zuo, Tongjuan Tang, Xinru Ge et al. "Pharmacokinetic evaluation of 24 representative components of Ling‐Gui‐Zhu‐Gan decoction in acute myocardial infarction model rats via a validated ultrahigh‐performance liquid chromatography–tandem mass spectrometry method". Rapid Communications in Mass Spectrometry 37, n.º 19 (22 de agosto de 2023). http://dx.doi.org/10.1002/rcm.9620.

Texto completo

Resumen

RationaleLing‐Gui‐Zhu‐Gan decoction (LGZGD), one of the 100 herbal classic formulas, is clinically used to treat chronic heart failure with remarkable curative effect. However, LGZGD pharmacokinetic parameters in pathological model rats are poorly understood, in particular for special components. As physicochemical properties are specific to each representative component, no standard sample preparation is available for absolute quantification of representative components of LGZGD in rat plasma.MethodsA specific, sensitive and high‐throughput ultrahigh‐performance liquid chromatography–tandem mass spectrometry (UHPLC/MS/MS) method capturing 24 representative components was developed and applied to evaluate the pharmacokinetic parameters of LGZGD in acute myocardial infarction (AMI) rat plasma after intragastric administration (2.4, 4.8 and 9.6 g/kg). Precipitation and extraction were selected and optimized for plasma preparation, and isopropanol precipitation could offer higher recovery and broader coverage.ResultsIt was expected that AMI could cause less absorption and slower elimination of most of active components of LGZGD. Most of newly reported special components absorbed quickly and eliminated slowly. The average elimination half‐life of the 24 representative components was 10.09 h, which is consistent with the dosage of LGZGD (twice daily).ConclusionsThe specificity, linearity, precision and accuracy, recovery, matrix effect and stability were validated according to Food and Drug Administration guidance. The validation results demonstrated that the method could be applied to evaluate the pharmacokinetic parameters of LGZGD in AMI rats. The pharmacokinetic parameters showed substantial improvement in quality research of LGZGD, thereby laying the groundwork for preclinical and clinical trials in chronic heart failure clinical efficacy.

Los estilos APA, Harvard, Vancouver, ISO, etc.

33

WEI, Linfeng, Xiaofei HU, Qi CHENG, Xingqi WU y Jian NI. "A dataset of spatial distribution of bioclimatic variables in China at 1 km resolution". China Scientific Data 7, n.º 4 (31 de diciembre de 2022). http://dx.doi.org/10.11922/11-6035.csd.2022.0003.zh.

Texto completo

Resumen

Bioclimatic variables are indicators reflecting the integrated relationship between living things and climate. They are often used to interprete the relationships between species, vegetations and climate in global change research, and further simulate the geographical distribution patterns of both species and vegetations, as well as their functional characteristics. Regional bioclimate datasets, however, have been rarely reported. Based on an ANUSPIN interpolated dataset (covering temperature, precipitation and sunshine percentage) of 1km-resolution climate variables in China at 30-year basis averaged from 1951 to 1980 and from 1981 to 2010, respectively, we calculated 9 kinds bioclimatic variables in this study, namely mean temperature of the coldest month, mean temperature of the warmest month, absolute maximum temperature, absolute minimum temperature, annual growing degree days above 0°C and 5°C, growing season precipitation, annual drought index and annual moisture index. We plotted their spatial distribution map and analyzed their spatial pattern and trend statistically. Comparative analysis shows that the variation range of corresponding variables is very narrow, and the statistical variables are nearly the same. Therefore, the error of this dataset mainly comes from the spatial distribution dataset of basic climatic factors, and the secondary error in the process is tiny.This dataset provides reasonable environmentally mechanistic explanations for research on the relationships between species, vegetations and climate, and offers a convenient and diverse way for researchers to use bioclimatic variables to simulate species distribution patterns, vegetation structures and functions.

Los estilos APA, Harvard, Vancouver, ISO, etc.

34

YANG, Siqi, Junyi LIU, Chuan YANG, Guoyu LAN, Bo SONG y Zhixiang WU. "A dataset of carbon and water fluxes and micrometerological elements in Danzhou rubber plantation (2010-2018)". China Scientific Data 7, n.º 4 (31 de diciembre de 2022). http://dx.doi.org/10.11922/11-6035.csd.2022.0063.zh.

Texto completo

Resumen

Rubber plantation is one of the main artificial vegetation types in Hainan Island. As an important forest ecosystem in China’s tropical regions, rubber plantation plays an important role in the regional carbon and water cycle. Measuring the carbon and water fluxes is critical for estimating the carbon and water balance and energy exchange of rubber plantation. Since November 2009, near-surface CO2 and H2O fluxes observation have been carried out in Danzhou rubber plantation, including eddy covariance system and meteorological observation system. Up to now, it has accumulated flux and meteorological observation data for 12 years. This dataset organizes the rubber plantation flux and conventional meteorological data in Danzhou from 2010 to 2018, including net ecosystem productivity, ecosystem respiration, gross ecosystem productivity, latent heat flux, sensible heat flux, evapotranspiration, air temperature, air relative humidity, vapor pressure, wind speed, wind direction, atmospheric pressure, total radiation, net radiation, photosynthetically active radiation, soil temperature, soil water content and precipitation. This dataset can provide basis and reference for ecosystem evaluation and sustainable development planning in economic and social.

Los estilos APA, Harvard, Vancouver, ISO, etc.

35

WANG, Yanwei, Weijun LUO, Jia CHEN, Xianli CAI, Lin ZHANG, Anyun CHENG y Shijie WANG. "A dataset of carbon and water fluxes in the sample plots of natural regeneration at Puding Station of Guizhou Province (2015–2019)". China Scientific Data 8, n.º 3 (30 de septiembre de 2023). http://dx.doi.org/10.11922/11-6035.csd.2023.0063.zh.

Texto completo

Resumen

Targeting the Shawan natural regeneration ecosystem (converted from farmland in 2010) in Puding County, we adopted the eddy covariance (EC) system to carry out long-term positioning observations of carbon and water fluxes during the natural regeneration of ecosystems after farmland conversion in karst areas. Puding Station belongs to the National Field Scientific Observation and Research Network and the China Ecosystem Research Network. Based on the data processing requirements of the ChinaFLUX, we compiled in this dataset the carbon and water fluxes as well as conventional meteorological data in Shawan from 2015 to 2019, including net ecosystem carbon exchange (NEE), ecosystem respiration (Re), gross primary productivity (GPP), latent heat flux (LE), sensible heat flux (H), air temperature, air relative humidity, wind speed, wind direction, total solar radiation, net radiation, precipitation and so on. This dataset can provide observational evidence for the study of the carbon sink capacity and water consumption characteristics of the ecosystem at the early stage of natural regeneration after the conversion of sloping farmland to forest in karst areas in southern China, as well as their response to climate change.

Los estilos APA, Harvard, Vancouver, ISO, etc.

36

JIANG, Shan, Heming LIU, Zemei ZHENG, Haibo YANG, Fangfang YAO, Xihua WANG y Enrong YAN. "A dataset of meteorological observations at Zhejiang Tiantong National Forest Ecosystem Observation and Research Station (2003 – 2017)". China Scientific Data 7, n.º 4 (31 de diciembre de 2022). http://dx.doi.org/10.11922/11-6035.csd.2022.0078.zh.

Texto completo

Resumen

Evergreen broad-leaved forests are one of the main types of Chinese forests. The meteorological data of them are of great value for the study on the function and ecological process of evergreen broad-leaved forest ecosystem, and can serve as a major data source for weather forecast and disaster warning. Zhejiang Tiantong National Forest Ecosystem Observation and Research Station located in the subtropical broad-leaved evergreen forest in Tiantong Forest Park in eastern China. Since April 2003, we had collected long-term meteorological data by setting up the automatic meteorological observation system. This dataset contains the monthly data (177 entries) and annual data (15 entries) from 2013 to 2017, including 18 meteorological observation indexes, such as atmospheric temperature, atmospheric humidity, precipitation, atmospheric pressure, total radiation, net radiation, reflected radiation, UV radiation, photosynthetically active radiation, sunshine hours and soil temperature in different depths (0 cm, 5 cm, 10 cm, 15 cm, 20 cm, 40 cm, 60 cm and 100 cm). It is expected to provide data support for studying the ecological process, evaluating ecosystem service function and increasing disaster warning accuracy of local forests in Tiantong zone.

Los estilos APA, Harvard, Vancouver, ISO, etc.

37

WANG, Xingchang, Keming HU, Fan LIU, Yuan ZHU, Quanzhi ZHANG y Chuankuan WANG. "A dataset of carbon fluxes of the deciduous broad-leaved forest at Maoershan Station from 2016 to 2018". China Scientific Data 8, n.º 2 (30 de junio de 2023). http://dx.doi.org/10.11922/11-6035.csd.2023.0024.zh.

Texto completo

Resumen

Forest ecosystem dominates the terrestrial ecosystem carbon (C) cycle, thus the accurate estimation of C flux in the forest ecosystem is essential to understanding the impact of global change on global C cycle. Based on the micrometeorology theory, the eddy covariance technique is one of the standard methods for C flux monitoring in terrestrial ecosystems, which has been widely used in the long-term monitoring of C flux in forests, grasslands, croplands and other ecosystems. Heilongjiang Maoershan Forest Ecosystem National Observation and Research Station has a continental monsoon climate, dominated by natural secondary forests (temperate deciduous broad-leaved forestd) which are typical in the montane forests of Northeast China. In this dataset, we compiled the measured C flux data and routine meteorological data of a deciduous broad-leaved forest at Maoershan Station from 2016 to 2018, including gross primary productivity, ecosystem respiration, net ecosystem exchange, incoming solar radiation, incoming photosynthetically active radiation, air temperature, soil temperature, soil moisture and precipitation. The dataset is divided into four time scales: half-hourly, daily, monthly and yearly. The establishment and sharing of this dataset will provide necessary, accurate and reliable data to support the evaluation of the role of natural secondary forests in the regional C cycle and the optimization of C cycle models.

Los estilos APA, Harvard, Vancouver, ISO, etc.

38

MA, Weidong, Wei JIA, Xingyun FENG, Yuantao ZHOU, Peng SU, Dan WEI, Chunying MAO, Yimeng JI, Fenggui LIU y Jing'ai WANG. "A dataset of spatial distribution of highland barley planting area on the Qinghai-Tibet Plateau (2019)". China Scientific Data 8, n.º 1 (31 de marzo de 2023). http://dx.doi.org/10.11922/11-6035.csd.2022.0092.zh.

Texto completo

Resumen

Highland barley is the dominant crop that can best adapt to the natural environment of the Qinghai-Tibet Plateau characterized by Alpine low temperature, hypoxia and strong radiation. In order to obtain the spatial distribution of the highland barley planting areas on the Qinghai-Tibet Plateau, we adopted a highland barley extraction method based on multi-element fusion of partition classification. First, we impose restrictions on the range of highland barley map spots of different agricultural partitions in terms of altitude, slope, precipitation and hydrological factors. Second, we optimized the optimal band for highland barley extraction through the OIF index partition. Finally, we used the object-oriented classification method to extract the planting areas of highland barley on the Qinghai-Tibet Plateau. The accuracy test of confusion matrix shows that the overall accuracy is 91.74% and Kappa coefficient is 0.83. According to the extraction results of highland barley on the Qinghai-Tibet Plateau, the total planting area of highland barley is about 2.74×105 hm2. The dataset improves the understanding of the existing highland barley spatial distribution pattern from the administrative unit scale to the patch scale. And it can provide data reference for optimizing the spatial distribution pattern of highland barley planting in the future.

Los estilos APA, Harvard, Vancouver, ISO, etc.

39

ZHANG, Yinfei, Yaping YANG, Xiafang YUE y Yang XU. "A dataset of vegetation phenology and change trends with a resolution of 500m of on the Mongolian Plateau (2001–2019)". China Scientific Data 8, n.º 1 (31 de marzo de 2023). http://dx.doi.org/10.11922/11-6035.csd.2022.0065.zh.

Texto completo

Resumen

Located in the highland of Eurasia, the Mongolian Plateau, a typical arid and semi-arid region, is highly sensitive to climate change. Vegetation phenology is the most intuitive and sensitive biological indicator of seasonal and interannual changes of climatic conditions. Vegetation phenology data can be used to explore the ecological situation and climate change of the Mongolian Plateau. Based on THE MODIS land cover Dynamic Product (MCD12Q2 C6), in this paper, we used non-parametric Theil-Sen Median trend analysis and Mann-Kendall significance test to extract sub-datasets, Mosaic, projection transformation and cropping. In this way, we obtained the data of four phenological periods (namely the beginning time, the end time, the length of the growing season and the peak time of the growing season) and the change trend data of vegetation of 500m resolution on the Mongolian Plateau from 2001 to 2019. This dataset can reflect the spatio-temporal changes of vegetation phenology in 19 years on the Mongolian Plateau. Combined with climate factors such as temperature and precipitation, it can be used to explore the response and feedback mechanism of vegetation phenology change to environmental factors, and provide data support for vegetation change analysis, climate change, carbon cycle and other studies.

Los estilos APA, Harvard, Vancouver, ISO, etc.

40

LIU, Fan, Yanjun SHEN, Jiansheng CAO y Yucui ZHANG. "A dataset of water, heat, and carbon fluxes over the winter wheat-summer maize croplands in Luancheng during 2013–2017". China Scientific Data 8, n.º 2 (30 de junio de 2023). http://dx.doi.org/10.11922/11-6035.csd.2023.0031.zh.

Texto completo

Resumen

The winter wheat-summer maize double-cropping agro-ecosystem holds the largest planting area in the North China Plain. The carbon and water flux observation data of the croplands are crucial to understanding regional carbon and water cycles and their regulation mechanism. Located in the piedmont Plain of Taihang Mountain, Luancheng Agro-ecosystem Experimental Station (Luancheng Station) is the typical groundwater irrigation district. We have been using the eddy covariance technology to carry out the observation work of the winter-summer maize croplands since October 2007. This is the dataset of water, heat, and carbon fluxes over the winter wheat-summer maize croplands in Luancheng from October 2013 to September 2017 (covering four complete growing seasons). The dataset includes latent heat flux (or evapotranspiration), sensible heat flux, net ecosystem exchange of CO2, solar radiation, photosynthetically active radiation, air temperature/humidity, precipitation, soil temperature and volumetric soil water content at the half-hourly, daily, crop-season, and crop-year scales. The network observation, quality control and storage process of this dataset strictly abide by ChinaFLUX data management technology system to ensure data reliability. This dataset can provide solid data support for deeply understanding the processes of water, heat and carbon exchange, and improving the management of water resource to relieve the overdraft of groundwater in North China.

Los estilos APA, Harvard, Vancouver, ISO, etc.

41

XU, Ziwei, Shaomin LIU, Xin LI, Tongren XU y Zhongli ZHU. "Water vapor-heat-carbon fluxes and meteorological observation matrix dataset in 2012 over Zhangye oasis-desert area". China Scientific Data 8, n.º 3 (30 de septiembre de 2023). http://dx.doi.org/10.11922/11-6035.csd.2023.0108.zh.

Texto completo

Resumen

The oasis-desert ecosystem is a unique landscape in arid/semi-arid regions, and the observation and research of its water vapor, heat, and carbon fluxes are of great significance to the stability and sustainable development of oases. This study focuses on the oasis-desert area of Zhangye City, Gansu Province, in the middle reaches of the Heihe River Basin. Based on the state-of-art flux observation matrix experiment conducted in the region in 2012, we processed the water vapor-heat-carbon fluxes and meteorological data from the experiment in two nested matrices (30 km × 30 km and 5.5 km × 5.5 km). There are a total of 22 eddy covariance systems and 21 automatic weather stations within the 21 observation sites as well as 4 group large aperture scintillometer and 3 group thermal dissipation probe observations in the two nested matrices. The observation parameters encompass a wide range of elements, including ecosystem net carbon exchange, latent heat flux, sensible heat flux, air temperature, relative humidity, wind speed, wind direction, downward/upward short wave radiation, downward/upward long wave radiation, net radiation, atmospheric pressure, precipitation, infrared radiation temperature, photosynthetic effective radiation, soil temperature, soil moisture, soil heat flux and average soil temperature, tree transpiration, etc. This meticulously processed dataset can be used to study the characteristics and impact mechanisms of water vapor, heat, and carbon changes in oasis-desert areas. Moreover, it can provide a strong data foundation for model simulation or remote sensing estimation results.

Los estilos APA, Harvard, Vancouver, ISO, etc.

42

ZHANG, Fawei, Mengke SI, Xiaowei GUO, Guangmin CAO y Zhenhua ZHANG. "A dataset of the observations of carbon, water and heat fluxes over an alpine meadow in Haibei (2015–2020)". China Scientific Data 8, n.º 2 (30 de junio de 2023). http://dx.doi.org/10.11922/11-6035.csd.2023.0012.zh.

Texto completo

Resumen

Covering an area of 5.04×105 km2 on the Qinghai-Tibetan Plateau, Alpine meadow is essential to the plateau ecological barrier function and regional sustainable development. Since May 2014, Haibei National Field Research Station for Alpine Grassland (Haibei Station hereafter) has been accumulating amounts of valuable data by employing eddy covariance techniques to continuously measure carbon and water cycles and energy exchanges between an alpine Graminoid-Kobresia meadow ecosystem and the atmosphere. In the following of data processing such as outlier removal and flux data gaps filled by boosted regression tree model, Haibei Station plans to publish a dataset of the continuous observations of carbon, water, and heat fluxes of the alpine meadow from 2015 to 2010. This dataset consists of the subsets of carbon, water, and heat fluxes data (i.e. net ecosystem CO2 exchange, ecosystem CO2 respiration, gross ecosystem CO2 exchange, latent heat flux, and sensible heat flux) and the subsets of routine meteorological data (i.e. air temperature, air relative humidity, total solar radiation, net radiation, photosynthetically active radiation, precipitation, soil temperature, volumetric soil moisture content). The temporal resolutions of the dataset are half-hourly, daily, monthly, and yearly scales. This dataset can be used to validate the parameters of processes-based ecological models of carbon and water cycles and to evaluate the spatiotemporal patterns and evolution trends in ecological functions of carbon sequestration and water-holding capacity in alpine meadow ecosystems.

Los estilos APA, Harvard, Vancouver, ISO, etc.

43

ZHANG, Fawei, Hongqin LI, Leiming ZHANG, Jiexia LI, Yongsheng YANG, Guirui YU y Yingnian LI. "A dataset of the observations of carbon, water and heat fluxes over an alpine shrubland in Haibei (2011–2020)". China Scientific Data 8, n.º 2 (30 de junio de 2023). http://dx.doi.org/10.11922/11-6035.csd.2023.0013.zh.

Texto completo

Resumen

Alpine shrubland is one of the important vegetation types on the Qinghai-Tibet Plateau, which mainly lies in the shady or semi-shady slope of snowpack mountains or the high-altitude alluvium and diluvium on plains. It plays a crucial role in carbon sequestration, water conservation and climate regulation. Since 2002, Haibei National Field Research Station for Alpine Grassland (Haibei Station) has been using eddy covariance techniques to continuously observe the carbon, water and heat exchange between an alpine Potentilla fruticosa shrubland ecosystem and the atmosphere and has accumulated nearly 20-year data. On the basis of the previous publication of relevant data from 2003 to 2010, the carbon, we further released water and heat fluxes of the alpine shrubland and supplementary meteorological data from 2011 to 2020. This dataset consists of the subsets of meteorological factors, covering air temperature, air relative humidity, water vapor pressure, wind speed, wind direction, ambient pressure, total solar radiation, net radiation, photosynthetically active radiation, precipitation, soil temperature, and soil moisture, as well as net ecosystem CO2 exchange, ecosystem respiration, gross ecosystem CO2 exchange, latent heat flux, and sensible heat flux. The temporal resolutions of the dataset include half-hourly, daily, monthly, and yearly scales. This dataset can not only be used to scientifically evaluate the environmental drivers and evolution trends of the ecological functions of carbon, water and heat in alpine shrub ecosystems, but also provide ground data support for parameter validation and optimization of remote sensing-based ecological process models.

Los estilos APA, Harvard, Vancouver, ISO, etc.

44

LI, Menghan, Juanle WANG y Kai LI. "A dataset of grass yield estimation with 30m resolution in Mongolia during 2017-2021". China Scientific Data 8, n.º 1 (31 de marzo de 2023). http://dx.doi.org/10.11922/11-6035.csd.2023.0006.zh.

Texto completo

Resumen

Grassland is the dominant vegetation type on the Mongolian Plateau. It is not only an important part of the ecological environment of the Mongolian Plateau, but also an important resource base for the development of animal husbandry in the Mongolian Plateau. As one of the evaluation indicators of grassland productivity, the grass yield has guiding significance for striking the balance between grassland and livestock. However, due to the long-term dependence on artificial investigation, there is a shortage of products for estimating grass yield in a large range, high spatial resolution and continuous time. Taking Mongolia as the research area, in this paper, we used Landsat8 remote sensing image, MODIS remote sensing data and meteorological data in combination with the measured sample data of grass yield in the field survey to obtain the relationship between the measured grass yield and the vegetation index NDVI, surface temperature and precipitation through the depth neural network. In this way, we constructed the estimation model of Mongolia's domestic grass yield suitable for the characteristics of the region. Moreover, we establish a deep neural network estimation model for grass yield, and retrieved the temporal and spatial distribution map of grass yield in Mongolia from 2017 to 2021. The precision verification experiment shows that the model based on deep learning has a high precision, with an RMSE of 12.14 g/m2 and an estimation accuracy of 81%, which can provide a method and data reference for the estimation of domestic grassland in Mongolia.

Los estilos APA, Harvard, Vancouver, ISO, etc.

45

Alexandrov, Alexander A., Mariya N. Mayakova, Valery V. Voronov, Daria V. Pominova, Sergey V. Kuznetsov, Alexander E. Baranchikov, Vladimir K. Ivanov, Elena I. Lysakova y Pavel P. Fedorov. "Синтез ап-конверсионных люминофоров на основе фторида кальция". Kondensirovannye sredy i mezhfaznye granitsy = Condensed Matter and Interphases 22, n.º 1 (20 de marzo de 2020). http://dx.doi.org/10.17308/kcmf.2020.22/2524.

Texto completo

Resumen

Исследование посвящено созданию люминофора на основе фторида кальция, легированного редкоземельными элементами: 5% Yb, 1% Er, с использованием методики синтеза из раствора в расплаве. В качестве растворителя использован нитрат натрия NaNO3, в качестве фторирующего агента – фторид натрия NaF. Полученные образцы охарактеризованы методами рентгенофазового анализа, рентгеноспектрального микроанализа, растровой электронной микроскопии и люминесцентной спектроскопии.В ходе работы исследовано влияние параметров синтеза на фазовый состав и морфологию частиц. Было установлено, что для формирования однофазных образцов – твёрдых растворов на основе фторида кальция – необходимо проводить синтез при температуре не ниже 400 °C, оптимальное время выдержки составило 3 ч. Установлен состав полученных образцов, он отличается от номинального и может быть записан как Ca0.88(Yb, Er)0.06Na0.06F2. Показано, что совместное вхождение натрия и ионов редкоземельных элементов повышает границы растворимости фториданатрия во фториде кальция. Энергетический выход люминесценции составил 1.21 %.По результатам работы был получен новый материал, обладающий ап-конверсионными свойствами. ЛИТЕРАТУРА Овсянкин В.В., Феофилов П.П. О механизме суммирования электронных возбуждений в акти-вированных кристаллах. Письма в ЖЭТФ. 1966;3(12):494–497. Режим доступа: http://www.jetpletters.ac.ru/ps/782/article_12079.pdf Auzel F. Compteur quantique par transfert d’energie entre deux ions de terres rares dans un tungstate mixte et dans un verre. C. R. Acad. Sci. B. 1966;262: 1016–1019. Fedorov P. P., Kuznetsov S. V., Osiko V. V. Elaboration of nanofl uorides and ceramics for optical and laser applications. In: Tressaud A., Poeppelmeier K. (eds.) Photonic and electronic properties of fl uoride materials: Progress in fl uorine science series. Amsterdam: Elsevier; 2016. p. 7–31. DOI: http://doi.org/10.1016/B978-0-12-801639-8.00002-7 Kostiv U., Rajsiglova L., Luptakova D., Pluhacek T., Vannucci L., Havlicek V., Engstova H., Jirak D., Slouf M., Makovicky P., Sedlacek R., Horak D. Biodistribution of upconversion/magnetic silica-coated NaGdF4:Yb3+/Er3+ nanoparticles in mouse models. RSC Adv. 2017;7: 45997–46006. DOI: https://doi.org/10.1039/c7ra08712h Zhao J., Zhu Y.-J., Chen F. Microwave-assisted solvothermal synthesis and upconversion luminescence of CaF2:Yb3+/Er3+ nanocrystals. J. Colloid Interface Sci. 2015;440: 39–45. DOI: http://doi.org/10.1016/j.jcis.2014.10.031 Rakov N., Maciel G. S., Xiao M. Upconversion fl uorescence and its thermometric sensitivity of Er3+: Yb3+ co-doped SrF2 powders prepared by combustion synthesis. Electron. Mater. Lett. 2014;10(5): 985–989. DOI: https://doi.org/10.1007/s13391-014-4030-9 Zhiping Z., Yingsen Y., Quamin S., Xiaotang L., Bingfu L., Yun Y. Preparation and characterization of CaF2:Yb3+, Er3+ up-conversion phosphor. Sci. Adv. Mater. 2017;9(3-4): 523–527. DOI: https://doi.org/10.1166/sam.2017.2334 Вахренёв Р. Г., Маякова М. Н., Кузнецов С. В., Рябова А. В., Поминова Д. В., Воронов В. В., Фёдоров П. П. Исследование синтеза и люминесцентных характеристик фторида кальция, легированного иттербием и эрбием, для биомедицинских приложений. Конденсированные среды и межфазные границы. 2016;18(4): 487–493. Режим доступа: https://journals.vsu.ru/kcmf/article/view/157 Yu. S., Zhi Y., Su H. Hydrothermal synthesis and upconversion properties of CaF2:Er3+/Yb3+ nanocrystals. J. Nanosci. Nanotechnol. 2014;14: 3380–3386. DOI: https://doi.org/10.1166/jnn.2014.7991 Ansaru A. A., Yadav R., Rai S. B. Physiochemical properties of greatly enhanced photoluminescence of aqueous dispersible upconversion CaF2:Yb/Ernanoparticles. Photochem. Photobiol. Sci. 2017;16: 890–896. DOI: https://doi.org/10.1039/c6pp00448b Rehmer A., Scheurell K., Kemnitz E. Formation of nanoscopic CaF2 via a fl uorolytic sol-gel process for antireflective coatings. J. Mater. Chem. C. 2015;3: 1716–1723. DOI: http://doi.org/10.1039/c4tc02510e Ritter B., Krahl T., Scholz G., Kemnitz E. Local Structures of Solid Solutions Sr1–xYxF2+x (x = 0...0.5) with fluorite structure prepared by sol-gel and mechanochemical syntheses. J. Phys. Chem. C. 2016;120(16): 8992–8999. DOI: http://doi.org/10.1021/acs.jpcc.6b01834 Fedorov P. P., Mayakova M. N., Аlexandrov А.А., Voronov V. V., Kuznetsov S. V., Baranchikov A. E., Ivanov V. K. The melt of sodium nitrate as a new medium for synthesis of fl uorides. Inorganics. 2018;6: 38. DOI: https://doi.org/10.3390/inorganics6020038 Ha J.-W., Sohn E.-H., Park I. J., Lee S.-B. Preparation of CaF2 microspheres by thermal decomposition of trifl uoroacetate precursor in molten salt medium. Mater. Lett. 2017;209: 357–359. DOI: http://doi.org/10.1016/j.matlet.2017.08.029 Chen C., Sun L.-D., Li Z.-X., Li L.-L., Zhung J., Zhang Y.-W., Yan C.-H. Ionic liquid-based route to spherical NaYF4 nanoclusters with the assistance of microwave radiation and their multicolor upconversion luminescence. Langmuir. 2010;26(11): 8797–8803. DOI: http://doi.org/10.1021/la904545a Guo H., Guo Y., Noh H. M., Moon B. K., Park S. H., Jeong J. H., Kim K. H. Elaboration, structure and luminescence of sphere-like CaF2:RE sub-microparticles by ionic liquids based hydrothermal process. J. Nanosci. Nanotechnol. 2016;16: 1146–1150. DOI: https://doi.org/10.1166/jnn.2016.10800 Deng X., Dai Y., Liu J., Zhou Y., Ma P., Cheng Z., Chen Y., Deng K., Li X., Hou Z., Li C., Lin J. Multifunctional hollow CaF2:Yb3+/Er3+/Mn2+-poly(2-Aminoethyl methacrylate) microspheres for Pt(IV) pro-drug delivery and tri-modal imaging. Biomaterials. 2015;50: 154–163. DOI: https://doi.org/10.1016/j.biomaterials.2015.01.040 Liang L., Liu Y., Bu C., Guo L., Sun W., Nuang N., Peng T., Sebo B., Pan M., Liu W., Guo S., Zhao X.-Z. Highly uniform, bifunctional core/double shell structured b-NaYF4:Er3+, Yb3+ @ SiO2@TiO2 hexagonal sub microprisms for high performance dye sensitized solar cells. Adv. Mater. 2013;25: 2174–2180. DOI: https://doi.org/10.1002/adma.201204847 Balabhadra S., Debasu M. L., Brites C. D. S., Ferreira R. A. S. Upconverting nanoparticles working as primary thermometers in different media. J. Phys. Chem. C. 2017;121: 13962–13968. DOI: https://doi.org/10.1021/acs.jpcc.7b04827 Рожнова Ю. А., Кузнецов С. В., Воронов В. В., Федоров П. П. Cинтез ап-конверсионных люминофоров на основе фторида стронция, легированного Ho3+ и Er3+, для визуализаторов двухмикронного излучения. Конденсированные среды и межфазные границы. 2016;18(3): 408–413. Режим доступа: https://journals.vsu.ru/kcmf/article/view/150 Rozhnova Yu. A., Luginina A. A., Voronov V. V., Ermakov R. P., Kuznetsov S. V., Ryabova A. V., Pominova D. V., Arbenina V. V., Osiko V. V., Fedorov P. P. White light luminophores based on Yb3+/Er3+/Tm3+- coactivated strontium fl uoride powders. Mater. Chem. Phys. 2014;148: 201–207. DOI: https://doi.org/10.1016/j.matchemphys.2014.07.032 Kuznetsov S., Ermakova Yu., Voronov V., Fedorov P., Busko D., Howard I. A., Richards B. S., Turshatov A. Up-conversion quantum yields of SrF2: Yb3+, Er3+ sub-micron particles prepared by precipitation from aqueous solution. J. Mater. Chem. C. 2018;6: 598–604. DOI: https://doi.org/10.1039/c7tc04913g Yasyrkina D. S., Kuznetsov S. V., Ryabova A. V., Pominova D. V., Voronov V. V., Ermakov R.P., Fedorov P. P. Dependence of quantum yield of up-conversion luminescence on the composition of fl uorite-type solid solution NaY1–x–yYbxEryF4. Nanosystems: physics, chemistry, mathematics. 2013;4(5): 648–656. Режим доступа: https://cyberleninka.ru/article/n/dependence-of-quantum-yield-of-up-conversion-luminescence-on-the-composition-of-fluorite-type-solidsolution-nay-1-x-yyb-xer-yf-4 Ryabova A. V., Pominova D. V., Krut’ko V. A., Komova M. G., Loschenov V. B. Spectroscopic research of upconversion nanomaterials based on complex oxide compounds doped with rare-earth ion pairs: Benefi t for cancer diagnostics by upconversion fl uorescence and radio sensitive methods. Photon Lasers Med. 2013;2: 117–128. DOI: https://doi.org/10.1515/plm-2013-0013 Федоров П. П., Соболев Б. П. Концентрационная зависимость параметров элементарных ячеек фаз M1–xRxF2+x со структурой флюорита. Кристаллография. 1992;37(5): 1210–1219. Федоров П. П., Маякова М. Н., Кузнецов С. В., Маслов В. А., Сорокин Н. И., Баранчиков А. Е., Иванов В. К., Пыненков А. А., Усламина М. А., Нищев К. Н. Фазовая диаграмма системы NaF–CaF2 и электропроводность твердого раствора на основе CaF2. ЖНХ. 2016;61(11): 1529–1536. DOI: https://doi.org/10.1134/S003602361611005X Sobolev B. P. The rare earth trifl uorides. P.1. The high-temperature chemistry of the rare earth trifl uorides. Barcelona: Institut d’Estudis Catalans; 2000. 521 p.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Artículos de revistas sobre el tema "Precipitation de ZHS"

Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros