Artykuły w czasopismach: „Crystals size”

1

Krause, Simon, Volodymyr Bon, Hongchu Du, Rafal E. Dunin-Borkowski, Ulrich Stoeck, Irena Senkovska i Stefan Kaskel. "The impact of crystal size and temperature on the adsorption-induced flexibility of the Zr-based metal–organic framework DUT-98". Beilstein Journal of Nanotechnology 10 (20.08.2019): 1737–44. http://dx.doi.org/10.3762/bjnano.10.169.

Pełny tekst źródła

Streszczenie:

In this contribution we analyze the influence of adsorption cycling, crystal size, and temperature on the switching behavior of the flexible Zr-based metal–organic framework DUT-98. We observe a shift in the gate-opening pressure upon cycling of adsorption experiments for micrometer-sized crystals and assign this to a fragmentation of the crystals. In a series of samples, the average crystal size of DUT-98 crystals was varied from 120 µm to 50 nm and the obtained solids were characterized by X-ray diffraction, infrared spectroscopy, as well as scanning and transmission electron microscopy. We analyzed the adsorption behavior by nitrogen and water adsorption at 77 K and 298 K, respectively, and show that adsorption-induced flexibility is only observed for micrometer-sized crystals. Nanometer-sized crystals were found to exhibit reversible type I adsorption behavior upon adsorption of nitrogen and exhibit a crystal-size-dependent steep water uptake of up to 20 mmol g−1 at 0.5 p/p 0 with potential for water harvesting and heat pump applications. We furthermore investigate the temperature-induced structural transition by in situ powder X-ray diffraction. At temperatures beyond 110 °C, the open-pore state of the nanometer-sized DUT-98 crystals is found to irreversibly transform to a closed-pore state. The connection of crystal fragmentation upon adsorption cycling and the crystal size dependence of the adsorption-induced flexibility is an important finding for evaluation of these materials in future adsorption-based applications. This work thus extends the limited amount of studies on crystal size effects in flexible MOFs and hopefully motivates further investigations in this field.

Style APA, Harvard, Vancouver, ISO itp.

2

Cheng, Zheng Dong, Min Shuai, Andres Mejia, Hua Wei Li, Zeng Kai Shi, Jiao Yan Ai, Wei Zhou i Ying Chen. "Disk-Shaped Colloids: The Synthesis and Applications of ZrP Crystals". Advanced Materials Research 787 (wrzesień 2013): 177–83. http://dx.doi.org/10.4028/www.scientific.net/amr.787.177.

Pełny tekst źródła

Streszczenie:

We performed systematic experiments on the synthesis of layered crystal α-ZrP and revealed the control of size, aspect ratio and size polydispersity of disk-shaped crystals. The growth of the disks is mediated by oriented attachment, taking place continuously throughout the hydrothermal treatment between various sized disks. The master of the synthesis of layered crystals will contribute to various applications such as the nanocomposites and liquid crystals.

Style APA, Harvard, Vancouver, ISO itp.

3

Sheridan, Lindsay M., Jerry Y. Harrington, Dennis Lamb i Kara Sulia. "Influence of Ice Crystal Aspect Ratio on the Evolution of Ice Size Spectra during Vapor Depositional Growth". Journal of the Atmospheric Sciences 66, nr 12 (1.12.2009): 3732–43. http://dx.doi.org/10.1175/2009jas3113.1.

Pełny tekst źródła

Streszczenie:

Abstract The relationship among aspect ratio, initial size, and the evolution of the size spectrum is explored for ice crystals growing by vapor deposition. Ice crystal evolution is modeled based on the growth of spheroids, and the ice size spectrum is predicted using a model that is Lagrangian in crystal size and aspect ratio. A dependence of crystal aspect ratio on initial size is discerned: more exaggerated shapes are shown to result when the initial crystals are small, whereas more isometric shapes are found to result from initially large crystals. This result is due to the nature of the vapor gradients in the vicinity of the crystal surface. The more rapid growth of the smaller crystals is shown to produce a period during which the size distribution narrows, followed by a broadening led by the initially smallest crystals. The degree of broadening is shown to depend strongly on the primary habit and hence temperature.

Style APA, Harvard, Vancouver, ISO itp.

4

Furuya, K., K. Matsuo, F. Munakata, Y. Akimune, J. Ye, Y. Yamamoto i I. Ishikawa. "Synthesis of large-size β–Si3N4 crystals". Journal of Materials Research 14, nr 5 (maj 1999): 1690–91. http://dx.doi.org/10.1557/jmr.1999.0228.

Pełny tekst źródła

Streszczenie:

Large-sized β–Si3N4 crystals up to 10 mm in length and 0.3 mm in diameter with low impurity concentration are successfully grown from silicon melt in a nitrogen atmosphere. By controlling the concentration of impurities in the silicon melt, a new kind of β–Si3N4 crystal, that is, a transparent coloring one with an absorption edge around a wavelength of 520 nm, is obtained.

Style APA, Harvard, Vancouver, ISO itp.

5

Kim, Hyun Su, Su Kyung Kang, Haoxiang Zhang, Elsa Tsegay Tikue, Jin Hyung Lee i Pyung Soo Lee. "Al-ZSM-5 Nanocrystal Catalysts Grown from Silicalite-1 Seeds for Methane Conversion". Energies 14, nr 2 (18.01.2021): 485. http://dx.doi.org/10.3390/en14020485.

Pełny tekst źródła

Streszczenie:

This study evaluated Al-ZSM-5 nanocrystals grown from silicalite-1 seed crystals as catalysts for the methane dehydroaromatization (MDA) reaction. Silicalite-1 seed crystals sized between 30 and 40 nm were used to grow Al-ZSM-5 under various synthesis conditions. The size of Al-ZSM-5 was significantly affected by the Si/Al ratio (SAR), synthesis time, and silica nutrients/seed crystal ratio (NSR). Larger crystals were obtained with an increased SAR in the synthesis sols. Gradual growth of Al-ZSM-5 occurred with synthesis time, although the growth in crystal size ceased at 5 h of synthesis at 120 °C, indicating the rapid growth of Al-ZSM-5 aided by the silicalite-1 seeds. Precise tuning of Al-ZSM-5 size was possible by changing the nutrient/silicalite-1 seed ratio; a higher NSR led to larger crystals. Two representative Al-ZSM-5 crystals with SARs of 35 and 140 were prepared for catalyst testing, and the crystal sizes were tailored to <100 nm by controlling NSR. The MDA reaction was conducted in the presence of the prepared Al-ZSM-5. The catalyst size exhibited distinct differences in catalyst stability, while the SAR of catalysts did not produce noticeable changes in the catalyst stability of the Al-ZSM-5 crystals and commercial zeolites in this reaction system.

Style APA, Harvard, Vancouver, ISO itp.

6

Kimura, Hideo, Masaru Sakamoto, Takenori Numazawa, Mitsunori Sato i Hiroshi Maeda. "Crystal growth of large size Dy3Al5O12 Garnet single crystals". Journal of Crystal Growth 99, nr 1-4 (styczeń 1990): 850–53. http://dx.doi.org/10.1016/s0022-0248(08)80039-5.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

7

Louis, Benoit, Aurélie Vicente, Christian Fernandez i Valentin Valtchev. "Crystal Size–Acid Sites Relationship Study of Nano- and Micrometer-Sized Zeolite Crystals". Journal of Physical Chemistry C 115, nr 38 (2.09.2011): 18603–10. http://dx.doi.org/10.1021/jp204234d.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

8

Shtukenberg, Alexander, i Bart Kahr. "Twisted crystals". Acta Crystallographica Section A Foundations and Advances 70, a1 (5.08.2014): C229. http://dx.doi.org/10.1107/s2053273314097708.

Pełny tekst źródła

Streszczenie:

Modern reviews on crystal growth and defects in crystals overlook the fact that a significant portion of materials can spontaneously grow as single crystals with twisted and bent morphologies and curved crystal lattices. Twisted crystals can be found among all types of materials (molecular crystals, salts, minerals, high polymers, metals, and elements) crystallizing in any point and space group from all types of growth media (vapor, solution, gel, glass, melt, and solid state). Their size spans over more than six orders of magnitude ranging from nm where 3D character is equivocal, to cm or dm (some of the biggest natural crystals). Here are illustrated most important features of twisted crystals as well as an analysis of mechanisms that are responsible for this mysterious phenomenon [1]. In general, formation of a twisted crystal is a complex phenomenon involving with certain requirements for dissymmetry, isomorphism, and crystal chemistry. Also critical are processes at the crystal-medium interface as well as the elasticity and plasticity of the crystalline medium. As such, twisting is strongly controlled by morphology and symmetry of the growth face. It frequently requires impurities, sometimes in extremely low concentrations. The intensity of deformation is inversely proportional to the crystal size. The phenomenon is more common when the driving force for crystallization and the temperature are high. Several mechanisms have been proposed to explain the formation of unusual curved morphologies: axial dislocation in whiskers (Eshelby twist); surface stress in polymer lamellae; surface charge and spontaneous polarization in nanoribbons; inhomogeneous fields forming around a growing crystal; and internal stress created by an inhomogeneous impurity distribution. However, most of the mechanisms proposed are insufficiently developed and need further verification and elaboration. The work was supported by the US National Science Foundation and New York University.

Style APA, Harvard, Vancouver, ISO itp.

9

Bespalov, V. I. "Large-Size Monosectorial Crystal Elements for Powerful Laser Systems". Journal of Nonlinear Optical Physics & Materials 06, nr 04 (grudzień 1997): 467–72. http://dx.doi.org/10.1142/s0218863597000344.

Pełny tekst źródła

Streszczenie:

The potentialities of fabricating large-size monosectorial crystals for powerful laser systems are discussed. Two types of technologies used for high-rate growth of profiled crystals and some results attained in crystal growth in the Institute of Applied Physics of the Russian Academy of Science are described briefly. It is concluded that the growth technique developed may be used for producing large-size optical elements (about 400 × 400 mm2) for laser systems intended for nuclear fusion experiments.

Style APA, Harvard, Vancouver, ISO itp.

10

Setasuwon, Paisan, i S. Kijamnajsak. "Effects of Starting Materials on Molten Salt Synthesis of Bi₄Ti₃O₁₂". Advanced Materials Research 55-57 (sierpień 2008): 165–68. http://dx.doi.org/10.4028/www.scientific.net/amr.55-57.165.

Pełny tekst źródła

Streszczenie:

Na0.5Bi0.5TiO3 is one of the potential candidates for non-lead piezoelectric materials to replace existing lead-based ones. Properties of BNT could be enhanced by reactive templated grain growth (RTGG) technique through induction of grain orientation with crystals of Bi4Ti3O12. Controlling the size of Bi4Ti3O12 crystals during the synthesis with molten salt is a major factor in optimizing RTGG. It was found that molten salt synthesis of Bi4Ti3O12 crystals with NaCl-KCl yielded larger particles, compared with Na2SO4-3K2SO4. Varying the proportion of chloride salt did not produce noticeable changes in crystal size. Bi4Ti3O12 crystals were significantly affected by raw materials treatment. Non-milling of starting powders could approximately double the crystal size

Style APA, Harvard, Vancouver, ISO itp.

11

Gualda, Guilherme A. R., David L. Cook, Rahul Chopra, Liping Qin, Alfred T. Anderson i Mark Rivers. "Fragmentation, nucleation and migration of crystals and bubbles in the Bishop Tuff rhyolitic magma". Earth and Environmental Science Transactions of the Royal Society of Edinburgh 95, nr 1-2 (marzec 2004): 375–90. http://dx.doi.org/10.1017/s0263593300001139.

Pełny tekst źródła

Streszczenie:

ABSTRACTThe Bishop Tuff (USA) is a large-volume, high-silica pyroclastic rhyolite. Five pumice clasts from three early stratigraphic units were studied. Size distributions were obtained using three approaches: (1) crushing, sieving and winnowing (reliable for crystals >100 μm); (2) microscopy of ∼1 mm3 fragments (preferable for crystals <100 μm); and (3) computerised X-ray microtomography of ∼1 cm3 pumice pieces.Phenocryst fragments coated with glass are common, and the size distributions for all crystals are concave-upward, indicating that crystal fragmentation is an important magmatic process.Three groups are recognised, characterised by: (1) high-density (0·759–0·902 g cm−3), high-crystal content (14·4–15·3 wt.%) and abundant large crystals (>800 μm); concave-downward size distributions for whole crystals indicate late-stage growth with limited nucleation, compatible with the slow cooling of a large, gas-saturated, stably stratified magma body; (2) low-density (0·499 g cm −3), low-crystal content (6·63 wt.%) and few large crystals; the approximately linear size distribution reveals that nucleation was locally important, perhaps close to the walls; and (3) intermediate characteristics in all respects.The volumetric fraction of bubbles inversely correlates with the number of large crystals. This is incompatible with isobaric closed-system crystallisation, but can be explained by sinking of large crystals and rise of bubbles in the magma

Style APA, Harvard, Vancouver, ISO itp.

12

Kärcher, B., A. Dörnbrack i I. Sölch. "Supersaturation Variability and Cirrus Ice Crystal Size Distributions". Journal of the Atmospheric Sciences 71, nr 8 (23.07.2014): 2905–26. http://dx.doi.org/10.1175/jas-d-13-0404.1.

Pełny tekst źródła

Streszczenie:

Abstract Small-scale dynamical variability affects atmospheric supersaturation and therefore the development of ice clouds via uptake of water vapor on ice crystals. This variability and its implications for ice growth are difficult to capture experimentally and theoretically. By interpreting supersaturation as a stochastic variable, the authors examine the average temporal behavior of, and the link between, supersaturation fluctuations and ice crystal size distributions in upper-tropospheric cirrus clouds. The authors classify cirrus types according to their ability to dampen supersaturation fluctuations owing to depositional growth of cloud ice and study how size distributions in them respond to supersaturation variability, investigating the possibility of the occurrence of ice-supersaturated states within cirrus. Typical time scales for growth and damping impacts on supersaturation are minutes and minutes to hours, respectively, and are highly variable among cirrus types and within single clouds. Transient deviations from saturated equilibrium states can occur depending on the ice crystal number concentration and size and on the strength of the small-scale dynamical forcing. Supersaturation preferentially occurs in cloud regions with few small ice crystals. The authors demonstrate that supersaturation fluctuations in very thin tropical tropopause cirrus create long-lived supersaturated states. Furthermore, they potentially generate few large ice crystals, broadening size distributions, and significantly enhance water mass fluxes due to sedimentation. Although not studied here, they may also allow new ice crystals to nucleate. Implications of these findings for those clouds to dehydrate air entering the lower stratosphere are discussed and future research needs are outlined.

Style APA, Harvard, Vancouver, ISO itp.

13

MATSUI, A. H., M. TAKESHIMA, K. MIZUNO i T. AOKI-MATSUMOTO. "PHOTOPHYSICAL OVERVIEW OF EXCITATION ENERGY TRANSFER IN ORGANIC MOLECULAR ASSEMBLIES — A ROUTE TO STUDY BIO-MOLECULAR ARRAYS —". International Journal of Modern Physics B 15, nr 28n30 (10.12.2001): 3857–60. http://dx.doi.org/10.1142/s0217979201008846.

Pełny tekst źródła

Streszczenie:

Excitonic processes in organic molecular crystals are discussed in terms of two parameters, the crystal size and the constituent molecule size. From the luminescence and absorption spectra of a series of aromatic molecular crystals we find a systematic change in exciton energy transport as functions of the size of crystal and its constituent molecule size. Characteristic features of bulk crystals and microcrystallites are as follows. (1) In bulk crystals exciton energy transport depends on the constituent molecule size. When molecules are small, the exciton energy transport occurs by free excitons, but when molecules are large free exciton transport disappears because excitons get self-trapped. (2) In microcrystallites, exciton energy transport depends on the crystallite size. When the size is larger than a critical one, excitons travel as quantum mechanical waves but when the size is smaller than the critical one the exciton waves get confined within the crystallite. The results are independent of the chemical species of constituent molecules and thus applicable to novel molecular arrays such as biological molecular arrays.

Style APA, Harvard, Vancouver, ISO itp.

14

Etschmann, Barbara, i Nobuo Ishizawa. "A synchrotron X-ray diffraction study of a small congruent LiNbO3 crystal: A compatible approach to powder diffraction". Powder Diffraction 16, nr 2 (czerwiec 2001): 81–85. http://dx.doi.org/10.1154/1.1365124.

Pełny tekst źródła

Streszczenie:

Single-crystal synchrotron X-ray diffraction (XRD) data were collected and refined for congruent lithium niobate crystals 8 and 6 μm in diameter, sizes that are comparable to the size of the powder particles used in powder diffraction. The motivation for using such small crystals is to minimize problems such as extinction, which decrease with crystal size. The R/wR factors were 0.011/0.014 and 0.019/0.018, for the 8 and 6 μm data, respectively, and the goodness of fit factors were 2.3(1) and 1.63(8), which compare favorably with values obtained from previous powder and single-crystal diffraction studies. Results from single-crystal XRD using crystals less than 10 μm in size may rival those obtained from powder diffraction.

Style APA, Harvard, Vancouver, ISO itp.

15

Klinkhammer, Barbara Mara, Sonja Djudjaj, Uta Kunter, Runolfur Palsson, Vidar Orn Edvardsson, Thorsten Wiech, Margret Thorsteinsdottir i in. "Cellular and Molecular Mechanisms of Kidney Injury in 2,8-Dihydroxyadenine Nephropathy". Journal of the American Society of Nephrology 31, nr 4 (21.02.2020): 799–816. http://dx.doi.org/10.1681/asn.2019080827.

Pełny tekst źródła

Streszczenie:

BackgroundHereditary deficiency of adenine phosphoribosyltransferase causes 2,8-dihydroxyadenine (2,8-DHA) nephropathy, a rare condition characterized by formation of 2,8-DHA crystals within renal tubules. Clinical relevance of rodent models of 2,8-DHA crystal nephropathy induced by excessive adenine intake is unknown.MethodsUsing animal models and patient kidney biopsies, we assessed the pathogenic sequelae of 2,8-DHA crystal-induced kidney damage. We also used knockout mice to investigate the role of TNF receptors 1 and 2 (TNFR1 and TNFR2), CD44, or alpha2-HS glycoprotein (AHSG), all of which are involved in the pathogenesis of other types of crystal-induced nephropathies.ResultsAdenine-enriched diet in mice induced 2,8-DHA nephropathy, leading to progressive kidney disease, characterized by crystal deposits, tubular injury, inflammation, and fibrosis. Kidney injury depended on crystal size. The smallest crystals were endocytosed by tubular epithelial cells. Crystals of variable size were excreted in urine. Large crystals obstructed whole tubules. Medium-sized crystals induced a particular reparative process that we term extratubulation. In this process, tubular cells, in coordination with macrophages, overgrew and translocated crystals into the interstitium, restoring the tubular luminal patency; this was followed by degradation of interstitial crystals by granulomatous inflammation. Patients with adenine phosphoribosyltransferase deficiency showed similar histopathological findings regarding crystal morphology, crystal clearance, and renal injury. In mice, deletion of Tnfr1 significantly reduced tubular CD44 and annexin two expression, as well as inflammation, thereby ameliorating the disease course. In contrast, genetic deletion of Tnfr2, Cd44, or Ahsg had no effect on the manifestations of 2,8-DHA nephropathy.ConclusionsRodent models of the cellular and molecular mechanisms of 2,8-DHA nephropathy and crystal clearance have clinical relevance and offer insight into potential future targets for therapeutic interventions.

Style APA, Harvard, Vancouver, ISO itp.

16

Lee, Chang Kyu, Jong Sung Kwon, In Chul Na, Byung Il Han, Young Min Kim i Jea Gun Park. "Dependency of Electrical Characteristics on Au Nano-Crystal Size for Non-Volatile Memory Fabricated with Au Nano-Crystal Embedded in PVK(Poly(N-Vinylcarbazole)) Layer". Solid State Phenomena 124-126 (czerwiec 2007): 33–36. http://dx.doi.org/10.4028/www.scientific.net/ssp.124-126.33.

Pełny tekst źródła

Streszczenie:

We demonstrated a nonvolatile memory fabricated with the sandwich device structure of Al/Au nano-crystals embedded in the PVK/Al. The bi-stable conduction switching characteristic (Ion/Ioff ratio) was >1x102, depending on Au nano-crystal size. The size and distribution of Au nano-crystals were determined by the inserted Au-layer thickness between PVK layers. The size of Au nano-crystals increased with the inserted Au-layer thickness. The uniform distribution of isolated Au nano-crystals was obtained with 5 nm of the inserted Au-layer thickness.

Style APA, Harvard, Vancouver, ISO itp.

17

K Schmidt, Karen Guldbæ, i Dorthe Dahl-Jensen. "An ice crystal model for Jupiter’s moon Europa". Annals of Glaciology 37 (2003): 129–33. http://dx.doi.org/10.3189/172756403781815735.

Pełny tekst źródła

Streszczenie:

AbstractA simple model for crystal growth in the ice shell of Europa has been made in order to estimate the size of ice crystals at Europa’s surface. If mass is lost from the surface of Europa due to sputtering processes, and the ice thickness is constant in time, ice crystals will be transported upwards in the ice shell. The crystals will therefore grow under varying conditions through the shell. The model predicts that ice crystals are 4 cm– 80 m across at the surface. For the preferred parameter values, a crystal size of the order of 7 m is calculated.

Style APA, Harvard, Vancouver, ISO itp.

18

Kreiliger, Thomas, Marco Mauceri, Marco Puglisi, Fulvio Mancarella, Francesco La Via, Danilo Crippa, Wlodek Kaplan i in. "3C-SiC Epitaxy on Deeply Patterned Si(111) Substrates". Materials Science Forum 858 (maj 2016): 151–54. http://dx.doi.org/10.4028/www.scientific.net/msf.858.151.

Pełny tekst źródła

Streszczenie:

The growth morphology of epitaxial 3C-SiC crystals grown on hexagonal pillars deeply etched into Si (111) substrates is presented. Different growth velocities of side facets let the top crystal facet evolve from hexagonal towards triangular shape during growth. The lateral size and separation between Si pillars determine the onset of fusion between neighboring crystals during growth at a height tailoring of which is crucial to reduce the stacking fault (SF) density of the coalesced surface. Intermediate partial fusion of neighboring crystals is shown as well as a surface of fully coalesced crystals.

Style APA, Harvard, Vancouver, ISO itp.

19

Nave, Colin. "Matching X-ray source, optics and detectors to protein crystallography requirements". Acta Crystallographica Section D Biological Crystallography 55, nr 10 (1.10.1999): 1663–68. http://dx.doi.org/10.1107/s0907444999008380.

Pełny tekst źródła

Streszczenie:

A review of the requirements for collecting X-ray diffraction data from protein crystals is given, with an emphasis on the properties of the crystal and its diffraction pattern. The size, unit-cell dimensions and perfection of the crystals can all be related to the required size and divergence of the incident X-ray beam, together with the size and spatial resolution of the detector. The X-ray beam causes primary radiation damage, even in frozen crystals. If the incident beam is very intense, temperature rises and gradients could occur in the crystal. The extent to which these problems can be overcome is also discussed.

Style APA, Harvard, Vancouver, ISO itp.

20

Liu, Botao, Yue Yu, Xia Tang i Bing Gao. "Improvement of Growth Interface Stability for 4-Inch Silicon Carbide Crystal Growth in TSSG". Crystals 9, nr 12 (7.12.2019): 653. http://dx.doi.org/10.3390/cryst9120653.

Pełny tekst źródła

Streszczenie:

The growth interface instability of large-size SiC growth in top-seeded solution growth (TSSG) is a bottleneck for industrial production. The authors have previously simulated the growth of 4-inch SiC crystals and found that the interface instability in TSSG was greatly affected by the flow field. According to our simulation of the flow field, we proposed a new stepped structure that greatly improved the interface stability of large-size crystal growth. This stepped structure provides a good reference for the growth of large-sized SiC crystals by TSSG in the future.

Style APA, Harvard, Vancouver, ISO itp.

21

Schlenczek, Oliver, Jacob P. Fugal, Gary Lloyd, Keith N. Bower, Thomas W. Choularton, Michael Flynn, Jonathan Crosier i Stephan Borrmann. "Microphysical Properties of Ice Crystal Precipitation and Surface-Generated Ice Crystals in a High Alpine Environment in Switzerland". Journal of Applied Meteorology and Climatology 56, nr 2 (luty 2017): 433–53. http://dx.doi.org/10.1175/jamc-d-16-0060.1.

Pełny tekst źródła

Streszczenie:

AbstractDuring the Cloud and Aerosol Characterization Experiment (CLACE) 2013 field campaign at the High Altitude Research Station Jungfraujoch, Switzerland, optically thin pure ice clouds and ice crystal precipitation were measured using holographic and other in situ particle instruments. For cloud particles, particle images, positions in space, concentrations, and size distributions were obtained, allowing one to extract size distributions classified by ice crystal habit. Small ice crystals occurring under conditions with a vertically thin cloud layer above and a stratocumulus layer approximately 1 km below exhibit similar properties in size and crystal habits as Antarctic/Arctic diamond dust. Also, ice crystal precipitation stemming from midlevel clouds subsequent to the diamond dust event was observed with a larger fraction of ice crystal aggregates when compared with the diamond dust. In another event, particle size distributions could be derived from mostly irregular ice crystals and aggregates, which likely originated from surface processes. These particles show a high spatial and temporal variability, and it is noted that size and habit distributions have only a weak dependence on the particle number concentration. Larger ice crystal aggregates and rosette shapes of some hundred microns in maximum dimension could be sampled as a precipitating cirrostratus cloud passed the site. The individual size distributions for each habit agree well with lognormal distributions. Fitted parameters to the size distributions are presented along with the area-derived ice water content, and the size distributions are compared with other measurements of pure ice clouds made in the Arctic and Antarctic.

Style APA, Harvard, Vancouver, ISO itp.

22

Garrett, T. J., M. B. Kimball, G. G. Mace i D. G. Baumgardner. "Observing cirrus halos to constrain in-situ measurements of ice crystal size". Atmospheric Chemistry and Physics Discussions 7, nr 1 (26.01.2007): 1295–325. http://dx.doi.org/10.5194/acpd-7-1295-2007.

Pełny tekst źródła

Streszczenie:

Abstract. In this study, characteristic optical sizes of ice crystals in synoptic cirrus are determined using airborne measurements of ice crystal size distributions, optical extinction and water content. The measurements are compared with coincident visual observations of ice cloud optical phenomena, in particular the 22° and 46° halos. In general, the scattering profiles derived from the in-situ cloud probe measurements are consistent with the observed halo characteristics. It is argued that this implies that the measured ice crystals were small, probably with characteristic optical radii between 10 and 20 μm. There is a current contention that in-situ measurements of high concentrations of small ice crystals reflect artifacts from the shattering of large ice crystals on instrument inlets. Significant shattering cannot be entirely excluded using this approximate technique, but it is not indicated. On the basis of the in-situ measurements, a parameterization is provided that relates the optical effective radius of ice crystals to the temperature in mid-latitude synoptic cirrus.

Style APA, Harvard, Vancouver, ISO itp.

23

Machatschek, Rainhard, Patrick Ortmann, Renate Reiter, Stefan Mecking i Günter Reiter. "Assembling semiconducting molecules by covalent attachment to a lamellar crystalline polymer substrate". Beilstein Journal of Nanotechnology 7 (2.06.2016): 784–98. http://dx.doi.org/10.3762/bjnano.7.70.

Pełny tekst źródła

Streszczenie:

We have investigated the potential of polymers containing precisely spaced side-branches for thin film applications, particularly in the context of organic electronics. Upon crystallization, the side-branches were excluded from the crystalline core of a lamellar crystal. Thus, the surfaces of these crystals were covered by side-branches. By using carboxyl groups as side-branches, which allow for chemical reactions, we could functionalize the crystal with semiconducting molecules. Here, we compare properties of crystals differing in size: small nanocrystals and large single crystals. By assembling nanocrystals on a Langmuir trough, large areas could be covered by monolayers consisting of randomly arranged nanocrystals. Alternatively, we used a method based on local supersaturation to grow large area single crystals of the precisely side-branched polymer from solution. Attachment of the semiconducting molecules to the lamellar surface of large single crystals was possible, however, only after an appropriate annealing procedure. As a function of the duration of the grafting process, the morphology of the resulting layer of semiconducting molecules changed from patchy to compact.

Style APA, Harvard, Vancouver, ISO itp.

24

Lie, Guang Hua, Zhi Lie Tang, Gan Wen Lie, Ting Yang, Xiu Wen Tang i Le Xi Shao. "Measure of the Optical Properties of Semiconductor Pb₃O₄ Nano-Crystalline of Using Photo-Acoustic Technology". Advanced Materials Research 354-355 (październik 2011): 246–50. http://dx.doi.org/10.4028/www.scientific.net/amr.354-355.246.

Pełny tekst źródła

Streszczenie:

The application of new single-beam normalized photo-acoustic spectroscopy in semiconductor Pb3O4 nano-crystals photo-acoustic spectroscopy was carried out. The measured spectra of semiconductor Pb3O4 nano-crystals absorption coefficient of 0.95, and then measured the semiconductor Pb3O4 nano-crystals powders band gap is 2.3 . The TEM image shows the semiconductor Pb3O4 nano-crystals are round granular structure, while the XRD spectrum indicates that the semiconductor Pb3O4 nano-crystals are tetragonal. The grain size measured to be about 30nm, and the average particle size after the reunion is 100nm. Compared with the micron crystal, the optical properties of semiconductor nano-crystals and nano-particle size are closely related. By changing the size of semiconductor nano-crystals, doped to change shape and optical, electrical properties of the goal. Because the defense and photoconductive materials with very special properties, they were widely used in many areas of modern technology, especially in delay bombings and stealth coating.

Style APA, Harvard, Vancouver, ISO itp.

25

Lie, Guang Hua, Zhi Lie Tang, Gan Wen Lie, Ting Yang i Xiu Wen Tang. "Measure of the Optical and Electrical Properties of Semiconductor SiO₂ Nano-Crystalline by Using Photo-Acoustic Technology". Advanced Materials Research 415-417 (grudzień 2011): 2156–59. http://dx.doi.org/10.4028/www.scientific.net/amr.415-417.2156.

Pełny tekst źródła

Streszczenie:

By using a new type of single-beam normalized photo-acoustic spectroscopy that with weak signal detection and non-invasive testing, the photo-acoustic spectroscopy of semiconductor SiO2 nano-crystals was measured，the measured spectra of semiconductor SiO2 nano-crystals absorption coefficient was 0.20, and powders band gap is 3.4eV. The TEM image shows that the semiconductor SiO2 nano-crystals are round lump structure, while the grain size of the semiconductor SiO2 nano-crystals is about 70x200 nm, and the average particle size after the reunion is 100x300 nm. Compared with their micron crystal, the optical and electrical properties of semiconductor nano-crystals and nano-particle size are closely related. By changing the size of semiconductor nano-crystals, the mix could achieve the goal of changing the optical and electrical properties. Because of the semiconductor SiO2 nano-crystals‘ special properties of optics and electronics and photo-semiconductor nano-materials, they are widely used in many areas of modern science and technology.

Style APA, Harvard, Vancouver, ISO itp.

26

Bowick, M. J. "Spherical crystals". Journal de Physique IV 12, nr 9 (listopad 2002): 221–25. http://dx.doi.org/10.1051/jp4:20020399.

Pełny tekst źródła

Streszczenie:

The structure of condensed matter order may change when the medium is curved. This is illustrated for the case of spherical crystals formed by self-assembled colloidal beads on water droplets in oil. Beyond a minimum crystal size novel grain boundary scars proliferate in the ground state.

Style APA, Harvard, Vancouver, ISO itp.

27

Ando, Shinji, Katsuhiro Oyabu, Kousei Hirayama, Masayuki Tsushida i Hideki Tonda. "Crack Propagation Behavior in Nano Size HCP Crystals by Molecular Dynamic Simulation". Key Engineering Materials 297-300 (listopad 2005): 280–85. http://dx.doi.org/10.4028/www.scientific.net/kem.297-300.280.

Pełny tekst źródła

Streszczenie:

A crack propagation behavior of hcp crystal has been simulated by molecular dynamics method using Lennard-Jones type potential. A notch was introduced to model crystals with free surfaces. The size of the model was 13nm×24nm×4.6nm and about 80000 atoms were included in the model. A crack propagated by applying tensile strain on top and bottom layer of the model crystal. A definite dependence of crystallographic orientation on crack propagation behavior was obtained. In a model crystal with initial notch plane and direction were (101 0), [1 210], the crack propagated parallel to notch plane and two sets of prismatic slips were occurred at the crack. Therefore, the crack in this crystal is deduced to extend by alternating shear on two intersecting {101 0}, <1 210> prismatic slip systems. In a model crystal with (0001), [101 0] initial crack, {101 1} first order pyramidal slip occurred at crack tip and following {101 2} twin was also observed. In a model crystal with (10 1 0), [0001] initial crack, the crack propagates parallel to initial crack plane. Crack propagation rate of the crack near surface is faster than the crack in interior of the model. In this case, two prismatic slips were occurred in front of the crack. This result explains a mechanism of forming ‘Herring-born pattern’ which was observed in the titanium single crystal. Results obtained by these three models are well described the fatigue crack propagation behavior in hcp titanium crystals.

Style APA, Harvard, Vancouver, ISO itp.

28

Miura, Sei, Yoshito Nishimura i Nagato Ono. "Sub-Grain Size and Hall-Petch Relation in Pure Copper Single Crystals". Key Engineering Materials 345-346 (sierpień 2007): 29–32. http://dx.doi.org/10.4028/www.scientific.net/kem.345-346.29.

Pełny tekst źródła

Streszczenie:

The effect of sub-grain on the yield stress of pure copper single crystals with the [253] orientation was investigated by using the etch pit technique. The single crystal plates were successfully prepared from the seed crystals, which were produced at the melting temperature of 1473 K by the Bridgeman method. The present investigation confirmed the Hall-Petch relation concerning the effect of sub-grain boundaries on the macroscopic yielding of pure copper. The result derived from the extrapolation of the relationship of critical resolved shear stress (CRSS) and the initial dislocation density and sub-grain size is in good agreement with the evaluation in high purity copper single crystals of low dislocation density.

Style APA, Harvard, Vancouver, ISO itp.

29

Antara, I. Nyoman Gde, K. I. Made Gatot, I. Made Budiana i Dae Kue Choi. "Morphological Analyses and Crystalline Structures of Anodic TiO₂ Thin Film on Ti6Al4V Alloy Using Phosphate and Calcium Containing Electrolyte under Different Voltage and Calcium Molarity". Applied Mechanics and Materials 776 (lipiec 2015): 215–22. http://dx.doi.org/10.4028/www.scientific.net/amm.776.215.

Pełny tekst źródła

Streszczenie:

This study was aimed at evaluating morphological and crystalline structures of anodic and hydrothermal titanium oxide thin films formed on Ti6Al4V alloy in a mixture of glycerol phosphate disodium salt (GP) and calcium acetate (CA) solution at various forming environments such as CA molarity and applied voltage. Anodic oxide films were hydrothermally treated and their morphological surfaces, crystal structures and chemical compositions were characterized. It was found that TiO2film was formed in all surfaces of Ti6Al4V alloy specimen with porous and rough morphology and the crystal structures were mainly anatase. The anodized film morphology and the crystals structure were dependent on CA molarity and anodizing voltage. Increasing CA molarity from 0.15 to 0.30M increased the number and size of micro porous and the intensity of anatase crystals, but further increasing to 0.45M, the number and size did not change and the intensity of anatase peaks became weak. Except in 0.45M-CA, the number and size of micro porous and the intensity of anatase crystals increased gradually with increasing anodizing voltage. Ca-P crystals were precipitated on the surface of hydrothermally treated films. CA molarity associated to the crystal shape while anodizing voltage related to the amount and size precipitated crystals. CA molarity was also associated to the atomic compositions of Ca and P that precipitated on the hydrothermally treated surface film.

Style APA, Harvard, Vancouver, ISO itp.

30

Bély, Miklós, i Ágnes Apáthy. "Mönckeberg’s sclerosis – crystal induced angiopathy". Orvosi Hetilap 154, nr 23 (czerwiec 2013): 908–13. http://dx.doi.org/10.1556/oh.2013.29628.

Pełny tekst źródła

Streszczenie:

Introduction: Mönckeberg’s sclerosis is a special form of arteriosclerosis characterized by calcification and ossification of the media of medium size arteries mainly of lower extremities. Aims: The aim of the authors was to examine medium size arteries with Mönckeberg’s sclerosis in 22 amputated lower legs of 16 patients in order to demonstrate different crystals in the wall of blood vessels. Methods: The methodology was based on previous findings of the authors indicating that in different metabolic disorders many crystals remain demonstrable in unstained histological sections unlike in haematoxylin-eosin stained sections. Results: In unstained sections the authors observed rhomboid or prismatic calcium pyrophosphate dihydrate and clusters of elongated narrow hydroxyapatite crystals in the wall of medium size arteries of all examined cases. Both types of crystals showed axis parallel positive birefringence under polarized light. The intensity of birefringence of hydroxyapatite crystals was weaker in comparison with that of calcium pyrophosphate dihydrate crystals. Occasionally, other crystals which were different in shape from both calcium pyrophosphate dihydrate and hydroxyapatite crystals were also observed. Conclusions: It seems likely that similarly to crystal deposition induced arthropathy, calcium pyrophosphate dihydrate, hydroxyapatite and other crystals cause fibrosis and intimal proliferation, which may contribute to progressive occlusion of blood vessels resulting in ischemic symptoms. Based on this observation Mönckeberg’s sclerosis may be defined as a crystal-induced angiopathy. Orv. Hetil., 2013, 154, 908–913.

Style APA, Harvard, Vancouver, ISO itp.

31

Zou, Yu, i Ralph Spolenak. "Size-dependent plasticity in micron- and submicron-sized ionic crystals". Philosophical Magazine Letters 93, nr 7 (lipiec 2013): 431–38. http://dx.doi.org/10.1080/09500839.2013.797616.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

32

NG, Felix, i T. H. Jacka. "A model of crystal-size evolution in polar ice masses". Journal of Glaciology 60, nr 221 (2014): 463–77. http://dx.doi.org/10.3189/2014jog13j173.

Pełny tekst źródła

Streszczenie:

AbstractIn the deep ice cores drilled at the GRIP, NGRIP and GISP2 sites in Greenland and at Byrd Station and the summit of Law Dome in Antarctica, the mean crystal size increases with depth in the shallow subsurface and reaches steady values at intermediate depth. This behaviour has been attributed to the competition between grain-boundary migration driven crystal growth and crystal polygonization, but the effects of changing crystal dislocation density and non-equiaxed crystal shape in this competition are uncertain. We study these effects with a simple model. It describes how the mean height and width of crystals evolve as they flatten under vertical compression, and as crystal growth and polygonization compete. The polygonization rate is assumed to be proportional to the mean dislocation density across crystals. Migration recrystallization, which can affect crystal growth via strain-induced grain boundary migration but whose impact on the mean crystal size is difficult to quantify for ice at present, is not accounted for. When applied to the five ice-core sites, the model simulates the observed crystal-size profiles well down to the bottom of their steady regions, although the match for Law Dome is less satisfactory. Polygonization rate factors retrieved for the sites range from 10–5 to 10–2 a–1. We conclude that since crystal size and dislocation density evolve in a strongly coupled manner, consistent modelling requires multiple differential equations to track both of these variables. Future ice-core analysis should also determine crystal size in all three principal directions.

Style APA, Harvard, Vancouver, ISO itp.

33

Tang, Xia, Botao Liu, Yue Yu, Sheng Liu i Bing Gao. "Numerical Analysis of Difficulties of Growing Large-Size Bulk β-Ga2O3 Single Crystals with the Czochralski Method". Crystals 11, nr 1 (30.12.2020): 25. http://dx.doi.org/10.3390/cryst11010025.

Pełny tekst źródła

Streszczenie:

The difficulties in growing large-size bulk β-Ga2O3 single crystals with the Czochralski method were numerically analyzed. The flow and temperature fields for crystals that were four and six inches in diameter were studied. When the crystal diameter is large and the crucible space becomes small, the flow field near the crystal edge becomes poorly controlled, which results in an unreasonable temperature field, which makes the interface velocity very sensitive to the phase boundary shape. The effect of seed rotation with increasing crystal diameter was also studied. With the increase in crystal diameter, the effect of seed rotation causes more uneven temperature distribution. The difficulty of growing large-size bulk β-Ga2O3 single crystals with the Czochralski method is caused by spiral growth. By using dynamic mesh technology to update the crystal growth interface, the calculation results show that the solid–liquid interface of the four-inch crystal is slightly convex and the center is slightly concave. With the increase of crystal growth time, the symmetry of cylindrical crystal will be broken, which will lead to spiral growth. The numerical results of the six-inch crystal show that the whole solid–liquid interface is concave and unstable, which is not conducive to crystal growth.

Style APA, Harvard, Vancouver, ISO itp.

34

Kusuma, Hamdan Hadi, Zuhairi Ibrahim i Zulkafli Othaman. "Estimation of Crystallite Size, Density, and Compositional of the Ti: Al2O3 Single Crystal". Jurnal Ilmiah Pendidikan Fisika Al-Biruni 9, nr 2 (30.10.2020): 295–302. http://dx.doi.org/10.24042/jipfalbiruni.v9i2.7207.

Pełny tekst źródła

Streszczenie:

The purposes of this research were to estimate the crystallite size, density, and chemical composition of the ingot Ti: Al2O3 crystal grown by the Czochralski method. The crystallite size and composition of Ti: Al2O3 crystals had been determined using x-ray diffraction (XRD) and energy-dispersive x-ray spectroscopy (EDXS). Based on the Archimedes principle, the density of the crystals had been determined. The XRD patterns showed a single central peak with high intensity for all samples. It indicated that all samples had a single crystal. The average value of the samples' crystallite size was in the range of 20.798 nm to 34.294 nm. The ingot crystal density and Ti composition increased from the top to the bottom part because the solid solution was distributed unevenly during the growth process.

Style APA, Harvard, Vancouver, ISO itp.

35

Kajikawa, Masahiro. "Structure and Falling Motion of Early Snowflakes". Annals of Glaciology 6 (1985): 269–71. http://dx.doi.org/10.3189/1985aog6-1-269-271.

Pełny tekst źródła

Streszczenie:

Relations between the structure and falling motion of early snowflakes, ie those composed of a few crystals, were investigated to clarify their growth process.The following results were obtained: (1) Two crystals of the same shape in a snowflake are similar in size, but those of different shape are considerably different in size. (2) In snowflakes having two crystals of the same shape, one crystal is attached near the center of the other; where the two are of different shapes, a smaller crystal is attached near the tip of the other. (3) The nondimensional amplitude of the spiral falling motion of snowflakes composed of two crystals of different shape, is slightly larger than for those with crystals of the same shape. This suggests that snowflakes composed of different shapes are more likely to aggregate to other snowflakes or crystals. (4) In snowflakes consisting ?G three crystals, the centers are usually arranged in a straight line. (5) The nondimensional amplitude of the spiral motion of snowflakes consisting of three crystals increases with departures from the straight-line arrangement of their centers.

Style APA, Harvard, Vancouver, ISO itp.

36

Kajikawa, Masahiro. "Structure and Falling Motion of Early Snowflakes". Annals of Glaciology 6 (1985): 269–71. http://dx.doi.org/10.1017/s0260305500010582.

Pełny tekst źródła

Streszczenie:

Relations between the structure and falling motion of early snowflakes, ie those composed of a few crystals, were investigated to clarify their growth process. The following results were obtained: (1) Two crystals of the same shape in a snowflake are similar in size, but those of different shape are considerably different in size. (2) In snowflakes having two crystals of the same shape, one crystal is attached near the center of the other; where the two are of different shapes, a smaller crystal is attached near the tip of the other. (3) The nondimensional amplitude of the spiral falling motion of snowflakes composed of two crystals of different shape, is slightly larger than for those with crystals of the same shape. This suggests that snowflakes composed of different shapes are more likely to aggregate to other snowflakes or crystals. (4) In snowflakes consisting ?G three crystals, the centers are usually arranged in a straight line. (5) The nondimensional amplitude of the spiral motion of snowflakes consisting of three crystals increases with departures from the straight-line arrangement of their centers.

Style APA, Harvard, Vancouver, ISO itp.

37

Maravić, Nikola, Zita Šereš, Jovana Petrović, Ljubica Dokić, Dragana Š. Simović, Miljana Djordjević, Marijana Djordjević i Ivana Nikolić. "Physico-Chemical Characteristics of White Sugar Fractions Separated by Crystal Sizes". Analecta Technica Szegedinensia 10, nr 2 (15.06.2016): 42–48. http://dx.doi.org/10.14232/analecta.2016.2.42-48.

Pełny tekst źródła

Streszczenie:

According to the EU Council Directive 2001/111/EC, related to certain sugars intended for human consumption, a great attention is paid to color in sugar. On the other hand, the non-sucrose compounds having intensive color tend to build into the sucrose crystals. Since Serbia has to work on the new rules concerned sugar quality and harmonization with EU standards, some investigations on sugar crystals are carried out at the request of some sugar factories. Investigations are carried out on sugar crystal size dependence on sugar color and on dissolution rate of different sugar crystal size fractions with the aim to create new sugar products. In this study, sugar samples with different sugar color are divided into 5 fractions by crystal size, defining size distributions. In each fraction the color in solution and the type of color are measured, as well as other relevant physico-chemical parameters. The conclusion is that the sugar color type depends on the crystal size, but sugar crystal solution is not dependent on crystal size except a fraction smaller than 200 mm, which has 30-75% higher sugar color in solution than the other crystal size fractions.

Style APA, Harvard, Vancouver, ISO itp.

38

Lonergan, C. E., K. Akinloye-Brown, J. Rice, V. Gervasio, N. Canfield, M. J. Schweiger i J. D. Vienna. "Micron-sized spinel crystals in high level waste glass compositions: Determination of crystal size and crystal fraction". Journal of Nuclear Materials 514 (luty 2019): 196–207. http://dx.doi.org/10.1016/j.jnucmat.2018.11.039.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

39

Kim, Ik Jin, Hae Jin Lee i Panagiotis Tsiakaras. "Effects of Seeding on Large Crystal Growth of NaX Zeolite by Continuous Crystallisation". Key Engineering Materials 280-283 (luty 2007): 861–64. http://dx.doi.org/10.4028/www.scientific.net/kem.280-283.861.

Pełny tekst źródła

Streszczenie:

The problem with zeolite crystals synthesized by conventional method is that they are extremely small of two to eight microns, To better define the structure of zeolite, scientist need to grow crystal that are 100 to 1000 times larger. In this work, Large crystal zeolite X of uniform crystal size of 50µm were grown by a continuous crystallization method from seed crystals (5-10µm) in a mother solution having a composition 3.5Na2O : Al2O3 : 2.1SiO2 : 1000H2O. In order to grow crystals of zeolite X to an appropriate size by the continuous method, the mother solution was supplied into the starting solution with various seed content (3~20wt%) in an autoclave at 90°C after 7 days, 12days, 16days, 19days and 24 days, respectively.

Style APA, Harvard, Vancouver, ISO itp.

40

HASHIMOTO, Shinobu, i Akira YAMAGUCHI. "Size Control of Spherical Leucite Crystals." Journal of the Ceramic Society of Japan 110, nr 1277 (2002): 27–31. http://dx.doi.org/10.2109/jcersj.110.27.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

41

HUSSEIN, M., U. BORG, C. NIORDSON i V. DESHPANDE. "Plasticity size effects in voided crystals". Journal of the Mechanics and Physics of Solids 56, nr 1 (styczeń 2008): 114–31. http://dx.doi.org/10.1016/j.jmps.2007.05.004.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

42

Bingrong, Huang, Su Genbo i He Youping. "Growth of large size urea crystals". Journal of Crystal Growth 102, nr 4 (czerwiec 1990): 762–64. http://dx.doi.org/10.1016/0022-0248(90)90839-d.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

43

Gavrilyachenko, V. G., V. D. Komarov, E. G. Fesenko i A. V. Leiderman. "Size effect in isometric PbTiO3 crystals". Physics of the Solid State 40, nr 8 (sierpień 1998): 1402–3. http://dx.doi.org/10.1134/1.1130568.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

44

Rylov, V. L., V. Z. Poilov i S. A. Amirova. "Potassium chloride crystals' industrial size enlargement". Crystal Research and Technology 23, nr 6 (czerwiec 1988): K100—K103. http://dx.doi.org/10.1002/crat.2170230626.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

45

Kuznetsov, V. A., A. G. Lipson, V. A. Klyuev, D. M. Sakov, Yu P. Toporov i Yu S. Simakov. "Size reduction of metal-halide crystals". Bulletin of the Academy of Sciences of the USSR Division of Chemical Science 38, nr 7 (lipiec 1989): 1340–43. http://dx.doi.org/10.1007/bf00978413.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

46

Chen, Wen-Hao, Zuo-Yan Qin, Xu-Yong Tian, Xu-Hui Zhong, Zhen-Hua Sun, Bai-Kui Li, Rui-Sheng Zheng, Yuan Guo i Hong-Lei Wu. "The Physical Vapor Transport Method for Bulk AlN Crystal Growth". Molecules 24, nr 8 (19.04.2019): 1562. http://dx.doi.org/10.3390/molecules24081562.

Pełny tekst źródła

Streszczenie:

In this report, the development of physical vapor transport (PVT) methods for bulk aluminum nitride (AlN) crystal growth is reviewed. Three modified PVT methods with different features including selected growth at a conical zone, freestanding growth on a perforated sheet, and nucleation control with an inverse temperature gradient are discussed and compared in terms of the size and quality of the bulk AlN crystals they can produce as well as the process complexity. The PVT method with an inverse temperature gradient is able to significantly reduce the nucleation rate and realize the dominant growth of only one bulk AlN single crystal, and thus grow centimeter-sized bulk AlN single crystals. X-ray rocking curve (XRC) and Raman spectroscopy measurements showed a high crystalline quality of the prepared AlN crystals. The inverse temperature gradient provides an efficient and relatively low-cost method for the preparation of large-sized and high-quality AlN seed crystals used for seeded growth, devoted to the diameter enlargement and quality improvement of bulk AlN single crystals.

Style APA, Harvard, Vancouver, ISO itp.

47

Mat Shaari, Nurul Elyni, Deny Susanti i Shafida Abd Hamid. "Essential Oils from the Leaves of Ocimum Basilicum L., Persicaria Odorata and Coriandrum Sativum L. In Malaysia: Antiurolithic Activity Study Based On Calcium Oxalate Crystallisation". Science Letters 15, nr 2 (15.06.2021): 13–25. http://dx.doi.org/10.24191/sl.v15i2.13809.

Pełny tekst źródła

Streszczenie:

Calcium oxalate is one of the most common components in urolithiasis. Its treatment includes the use of synthetic drugs, ultrasound and surgery. However, cheaper alternative treatment using herbal medicine with less adverse side effect is preferred. Essential oils from Thai basil (Ocimum bacilicum L.), Vietnamese coriander (Persicaria odorata) and Chinese parsley (Coriandum sativum L.) were extracted and investigated for antiurolithic activity based on calcium oxalate crystallisation. Most of the crystals formed in control sample were hexagonal calcium oxalate monohydrate with sizes ranging between 3 to 4 m. The size of the crystals was found to be slightly reduced in O. bacilicum oil (2-4 m) at high concentration with less aggregation of crystals. Samples with P. odorata oil gave smaller crystal size (3 m) mainly in dehydrate form and the oil was also found to inhibit the aggregation of the crystals at high concentration. C. sativum oil enhanced crystallisation (5-6 m) with increased concentration and showed high aggregation of the crystals. This preliminary study shows the therapeutic potential of these medicinal plants to be used in traditional anti-urolithic therapy.

Style APA, Harvard, Vancouver, ISO itp.

48

Gerber, H., i P. J. DeMott. "Response of FSSP-100 and PVM-100A to Small Ice Crystals". Journal of Atmospheric and Oceanic Technology 31, nr 10 (1.10.2014): 2145–55. http://dx.doi.org/10.1175/jtech-d-13-00228.1.

Pełny tekst źródła

Streszczenie:

Abstract Correction factors Cf are derived for ice-crystal volume and effective radius Re, measured by Forward Scattering Spectrometer Probe (FSSP) and Particulate Volume Monitor (PVM) that are known to overestimate both parameters for nonspherical particles. Correction factors are based on ice-crystal volume and the projected area of randomly oriented model ice crystals with column, rosette, capped-column, and dendrite habits described by Takano and Liou. In addition, Cf are calculated for oblate and prolate spheroids. To test Cf, both probes are compared to small, predominately solid hexagonal ice-crystal plates and columns generated in the Colorado State University (CSU) Dynamic Cloud Chamber (DCC). The tendency of heat released by the PVM (placed inside the chamber) to evaporate ice crystals and the smaller upper size range of the PVM than the size range of the FSSP caused large differences in the probes’ outputs for most comparisons in the DCC. Correction factors improved the accuracy of Re measured by the FSSP for the solid hexagonal crystals, and both probes produced similar results for the projected area and ice water content when crystal sizes fell within the probes’ size ranges. The modification for minimizing ice-crystal shattering and the application of Cf for forward scatter probes such as the FSSP suggests the probes’ improved usefulness for measuring small ambient ice crystals.

Style APA, Harvard, Vancouver, ISO itp.

49

Carter, Daniel C., Percy Rhodes, Duncan E. McRee, Leslie W. Tari, Douglas R. Dougan, Gyorgy Snell, Enrique Abola i Raymond C. Stevens. "Reduction in diffuso-convective disturbances in nanovolume protein crystallization experiments". Journal of Applied Crystallography 38, nr 1 (19.01.2005): 87–90. http://dx.doi.org/10.1107/s0021889804028055.

Pełny tekst źródła

Streszczenie:

Preliminary studies suggest that protein crystallization experiments using nanoliter-volume protein crystallization droplets may produce equal or better quality protein crystals compared with those grown using microliter volumes, and sometimes produce crystals in nanoliter volumes when microliter volumes are unable to produce diffraction-quality crystals. Computations and numerical modelling studies were performed to compare the influence of solutal convective disturbances around growing crystals and different drop volumes. These studies suggest that both crystal size and drop size contribute to a marked reduction in diffuso-convective disturbances in nanoliter drops and thus to the observed quality enhancements.

Style APA, Harvard, Vancouver, ISO itp.

50

Guidi, Vincenzo, Valerio Bellucci, Riccardo Camattari i Ilaria Neri. "Proposal for a Laue lens with quasi-mosaic crystalline tiles". Journal of Applied Crystallography 44, nr 6 (4.10.2011): 1255–58. http://dx.doi.org/10.1107/s0021889811035709.

Pełny tekst źródła

Streszczenie:

Quasi-mosaicity is an effect of secondary bending within a crystal driven by crystalline anisotropy. This effect can be used to fabricate a series of curved crystals for the realization of a Laue lens. It is highlighted that crystals bent by the quasi-mosaic effect allow very high resolution focusing with respect to mosaic crystals. Under the same conditions for energy passband, crystal size and flux of incident photons, a Laue lens based on quasi-mosaic crystals would increase the signal-to-noise ratio by about an order of magnitude compared to the same lens with mosaic crystals. Moreover, no mosaic defocusing occurs for quasi-mosaic crystals.

Style APA, Harvard, Vancouver, ISO itp.

Artykuły w czasopismach na temat „Crystals size”

Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych