Kliknij ten link, aby zobaczyć inne rodzaje publikacji na ten temat: Lanthanum oxide (La2O3).
Artykuły w czasopismach na temat „Lanthanum oxide (La2O3)”
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 50 najlepszych artykułów w czasopismach naukowych na temat „Lanthanum oxide (La2O3)”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj artykuły w czasopismach z różnych dziedzin i twórz odpowiednie bibliografie.
1
Karthikeyan.S i Selvapandiyan.M. "Facile synthesis of nanoplates and nanoflower shaped La2O3 nanostructures by Reflux Route". INTERNATIONAL JOURNAL OF SCIENCE TECHNOLOGY AND HUMANITIES 2, nr 2 (30.10.2015): 95–98. http://dx.doi.org/10.26524/ijsth64.
Pełny tekst źródłaStreszczenie:
Lanthanum Oxide (La2O3 ) nanoparticles are successfully synthesized by simple reflux method using starting materials Lanthanum Nitrate and Urea. Lanthanum Oxide (La2O3 ) have multiple applications such as gas sensors, catalyst, Hydrogen storage, catalysts, photocatalytic wet oxidation etc. This paper mainly focuses on the synthesis of Lanthanum Oxide (La2O3 ) nanoparticles at different precursor concentration at different reaction time on the properties of the synthesized Lanthanum Oxide (La2O3) nanoparticles can be explored. The synthesized samples were calcinated 500ºC for 1hr. The Lanthanum Oxide (La2O3) nanoparticles were investigated by XRD, FTIR, SEM, & UV studies. The morphology and particle size were analyzed by SEM. The structure of the crystallites was investigated using powder XRD technique. The FTIR analysis was used to examine the functional groups present in the synthesized Lanthanum Oxide (La2O3) nanoparticles. The optical band gap was calculated from the UV-Vis absorption spectra
2
Karthikeyan.s, Divya.j, Selvapandiyan.M i Arumugam.J. "Synthesis of Nickel Oxide Thin Films via Sol Gel Route". INTERNATIONAL JOURNAL OF SCIENCE TECHNOLOGY AND HUMANITIES 2, nr 2 (30.10.2015): 99–101. http://dx.doi.org/10.26524/ijsth65.
Pełny tekst źródłaStreszczenie:
Lanthanum Oxide (La2O3) nanoparticles are successfully synthesized by simple reflux method using starting materials Lanthanum Nitrate and Urea. Lanthanum Oxide (La2O3) have multiple applications such as gas sensors, catalyst, Hydrogen storage, catalysts, photocatalytic wet oxidation etc. This paper mainly focuses on the synthesis of Lanthanum Oxide (La2O3) nanoparticles at different precursor concentration at different reaction time on the properties of the synthesized Lanthanum Oxide (La2O3) nanoparticles can be explored. The synthesized samples were calcinated 500ºC for 1hr. The Lanthanum Oxide (La2O3) nanoparticles were investigated by XRD, FTIR, SEM, & UV studies. The morphology and particle size were analyzed by SEM. The structure of the crystallites was investigated using powder XRD technique. The FTIR analysis was used to examine the functional groups present in the synthesized Lanthanum Oxide (La2O3) nanoparticles. The optical band gap was calculated from the UV-Vis absorption spectra.
3
Samin, Samin, Suyanti Suyanti, Susanna Tuning Sunanti i Wisnu Ari Adi. "Synthesis and Certification of Lanthanum Oxide Extracted from Monazite Sand". Indonesian Journal of Chemistry 20, nr 6 (5.10.2020): 1213. http://dx.doi.org/10.22146/ijc.44327.
Pełny tekst źródłaStreszczenie:
Synthesis and certification of lanthanum oxide extracted from monazite sand have been carried out. This research aimed to increase the added value of monazite sand and obtain the lanthanum oxide in-house certified reference material (CRM). Synthesis of lanthanum oxide consists of several stages, namely: monazite sand digestion, rare-earth elements hydroxide [REE(OH)3] precipitation, Ce separation, Nd separation, lanthanum oxalate precipitation, and calcination. Certification of lanthanum oxide was carried out by determining the average concentration of the oxides and its uncertainty from the seven accredited laboratories by the ISO 35-2006 statistical method. Two other minerals in the lanthanum oxide analyzed by the XRD method were cerium hydroxide [Ce(OH)3] and neodymium yttrium oxide fluoride (Nd2Y2O3F16). Lanthanum oxide certified contains ten oxides, with the two highest concentrations of La2O3 (91.662 ± 0.007)% and Nd2O3 (3.949 ± 0.002)%. Lanthanum oxide has met the qualification in-house CRM since it contained water less than 1%, was homogeneous, stable, and certified. La2O3 concentration in the lanthanum oxide in-house CRM from CSAT-BATAN, Indonesia was not significantly different in comparison to that from the Department of Chemical Engineering, Srinakharinwirot University, Thailand. Lanthanum oxide extracted from monazite sand can be used as reference material in determining the lanthanum oxide quality from the pilot plant process.
4
Han, Hong Jing, Yan Guang Chen, Cong Hao Xie, Dan Dan Yuan, Ying Chen i Bao Hui Wang. "Influence of La2O3 on NOx Emission in Iron Ore Sintering". Advanced Materials Research 781-784 (wrzesień 2013): 2594–97. http://dx.doi.org/10.4028/www.scientific.net/amr.781-784.2594.
Pełny tekst źródłaStreszczenie:
NOx emission in coke combustion with and without La2O3 was investigated in a fixed bed quartz reactor. The effects of La2O3 loading and lanthanum oxide particle size on NOx emission were discussed. NOx emission was also studied by sintering pot tests with lanthanum oxide modified coke as sintering fuel. The results showed that lanthanum oxide was catalytically active in promoting not only coke combustion but also NOx reduction. In coke combustion experiments, NOx and CO emission decreased with increasing lanthanum oxide loading up to 2.0wt% and decreasing lanthanum oxide particle size (28~150μm).
5
Sun, Yunhan, Xiaoning Wang, Qingxiu Jia i Jian Yang. "Study on Organic Modification of Lanthanum Oxide". Journal of Physics: Conference Series 2194, nr 1 (1.02.2022): 012032. http://dx.doi.org/10.1088/1742-6596/2194/1/012032.
Pełny tekst źródłaStreszczenie:
Abstract In this paper, lanthanum oxide was modified by silane coupling agent (KH560), titanate coupler NDZ-201 and dopamine hydrochloride (DP). The microstructure and chemical structure of modified La2O3 were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), and the dispersion of modified lanthanum oxide in polypropylene (PP) was investigated. The results show that the three modifiers can improve the organic properties of lanthanum oxide, and the interfacial compatibility between dopamine modified La2O3 and PP is better than the other two modifiers.
6
Upolovnikova, A. G., A. A. Babenko i L. A. Smirnov. "Equilibrium content of lanthanum in metal under the slag of СаО – SiO2 – La2O3 – 15 % Al2O3 – 8 % MgO system". Izvestiya. Ferrous Metallurgy 63, nr 11-12 (3.01.2021): 946–51. http://dx.doi.org/10.17073/0368-0797-2020-11-12-946-951.
Pełny tekst źródłaStreszczenie:
Thermodynamic modeling results of lanthanum equilibrium content in metal under the slag of CaO – SiO2– La2О3– Al2O3– MgO system corresponding to chemical composition of 16 points of local simplex plan are presented using the HSC 8.03 Chemistry (Outokumpu) software package in combination with the simplex planning lattice method. In the work, slag is represented by CaO – SiO2– La2O3– – 15 % Al2O3– 8 % MgO oxide system in a wide range of chemical composition for temperatures of 1550 and 1650 °C, and metal contains 0.06 % C, 0.25 % Si, 0.05 % Al (in this expression and hereinafter in mass.%). The results of mathematical modeling are shown graphically in the form of composition - equilibrium content diagrams of lanthanum. There is significant effect of slag basicity on the lanthanum equilibrium content in metal. An increase in slag basicity from 2 to 5 at temperature of 1550 °C leads to an increase in the lanthanum equilibrium content from 0.2 ppm in the region of lanthanum oxide concentration of 1 – 5 % to 7 ppm in the region of increased concentration of lanthanum oxide to 4 – 7 %, hence the increase in slag basicity favorably affects development of lanthanum reduction. Increase in metal temperature also has positive effect on lanthanum reduction process. As temperature rises to 1650 °C, the lanthanum equilibrium content in metal increases from 0.2 ppm in the region of lanthanum oxide concentration of 1 – 3 % to 12 ppm in the region of increased concentration of lanthanum oxide to 4 – 7 %. In diagrams of chemical composition of slag containing 56 – 61 % CaO, 12 – 14 % SiO2and 4 – 7 % La2O3, the lanthanum content in metal at level of 7 – 12 ppm is ensured in temperature range from 1550 to 1650 °C. Therefore, there can be confirmed a decisive role of slag basicity, concentration of lanthanum oxide and temperature factor in development of lanthanum reduction from slags of the studied oxide system by aluminum dissolved in metal.
7
Upolovnikova, A. G., A. A. Babenko i L. A. Smirnov. "Equilibrium content of lanthanum in metal under the slag of СаО – SiO2 – La2O3 – 15 % Al2O3 – 8 % MgO system". Izvestiya. Ferrous Metallurgy 63, nr 11-12 (3.01.2021): 946–51. http://dx.doi.org/10.17073/0368-0797-2020-11-12-946-951.
Pełny tekst źródłaStreszczenie:
Thermodynamic modeling results of lanthanum equilibrium content in metal under the slag of CaO – SiO2 – La2О3 – Al2O3 – MgO system corresponding to chemical composition of 16 points of local simplex plan are presented using the HSC 8.03 Chemistry (Outokumpu) software package in combination with the simplex planning lattice method. In the work, slag is represented by CaO – SiO2 – La2O3 – – 15 % Al2O3 – 8 % MgO oxide system in a wide range of chemical composition for temperatures of 1550 and 1650 °C, and metal contains 0.06 % C, 0.25 % Si, 0.05 % Al (in this expression and hereinafter in mass.%). The results of mathematical modeling are shown graphically in the form of composition - equilibrium content diagrams of lanthanum. There is significant effect of slag basicity on the lanthanum equilibrium content in metal. An increase in slag basicity from 2 to 5 at temperature of 1550 °C leads to an increase in the lanthanum equilibrium content from 0.2 ppm in the region of lanthanum oxide concentration of 1 – 5 % to 7 ppm in the region of increased concentration of lanthanum oxide to 4 – 7 %, hence the increase in slag basicity favorably affects development of lanthanum reduction. Increase in metal temperature also has positive effect on lanthanum reduction process. As temperature rises to 1650 °C, the lanthanum equilibrium content in metal increases from 0.2 ppm in the region of lanthanum oxide concentration of 1 – 3 % to 12 ppm in the region of increased concentration of lanthanum oxide to 4 – 7 %. In diagrams of chemical composition of slag containing 56 – 61 % CaO, 12 – 14 % SiO2 and 4 – 7 % La2O3 , the lanthanum content in metal at level of 7 – 12 ppm is ensured in temperature range from 1550 to 1650 °C. Therefore, there can be confirmed a decisive role of slag basicity, concentration of lanthanum oxide and temperature factor in development of lanthanum reduction from slags of the studied oxide system by aluminum dissolved in metal.
8
Sun, Yunhan, Xiaoning Wang, Qingxiu Jia i Jian Yang. "Preparation of modified rare earth lanthanum oxide/polypropylene nonwoven fabric by meltblown method". Journal of Physics: Conference Series 2194, nr 1 (1.02.2022): 012046. http://dx.doi.org/10.1088/1742-6596/2194/1/012046.
Pełny tekst źródłaStreszczenie:
Abstract Lanthanum oxide was organically modified with dopamine and blended with polypropylene, and then lanthanum oxide (La2O3)/polypropylene (PP) nonwovens were prepared by melt blown method. The nonwovens were characterized by FTIR, SEM, TG, mechanical properties and X-ray shielding. The experimental results show that the addition of modified La2O3 makes the fiber arrangement of PP nonwovens more densely arranged and improves the thermal stability of PP nonwovens. The higher the amount of La2O3, the better the X-ray shielding performance of composite nonwovens.
9
Ganesh, Vanga, Thekrayat H. AlAbdulaal, Manal AlShadidi, Mai S. A. Hussien, Abdelfatteh Bouzidi, Hamed Algarni, Heba Y. Zahran i in. "Enhancement in the Structural, Electrical, Optical, and Photocatalytic Properties of La2O3-Doped ZnO Nanostructures". Materials 15, nr 19 (2.10.2022): 6866. http://dx.doi.org/10.3390/ma15196866.
Pełny tekst źródłaStreszczenie:
A lanthanum oxide (La2O3)-ZnO nanostructured material was synthesized in the proposed study with different La2O3 concentrations, 0.001 g to 5 g (named So to S7), using the combustion method. X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transformation infrared spectroscopy (FT-IR) were utilized for investigating the structure, morphology, and spectral studies of the La2O3- ZnO nanomaterials, respectively. The results obtained from previous techniques support ZnO’s growth from crystalline to nanoparticles’ fine structure by changing the concentrations of lanthanum oxide (La2O3) dopants in the host matrix. The percentage of ZnO doped with La- influences the ZnO photocatalytic activity. SEM analysis confirmed the grain size ranged between 81 and 138 nm. Furthermore, UV-Vis diffuse reflectance spectroscopy was performed to verify the effects of La2O3 dopants on the linear optical properties of the nano-composite oxides. There was a variation in the energy bandgaps of La2O3-ZnO nanocomposites, increasing the weight concentrations of lanthanum dopants. The AC electrical conductivity, dielectric properties, and current–voltage properties support the enactment of the electrical characteristics of the ZnO nanoparticles by adding La2O3. All the samples under investigation were used for photodegradation with Rhodamine B (RhB) and Methylene Blue (MB). In less than 30 min of visible light irradiation, S4 (0.5 g) La2O3-ZnO reached 99% of RhB and MB degradation activity. This study showed the best photocatalytic effect for RhB and MB degradation of 0.13 and 0.11 min−1 by 0.5 g La2O3-ZnO. Recycling was performed five times for the nanocatalysts that displayed up to 98 percent catalytic efficiency for RhB and MB degradation in 30 min. The prepared La2O3-ZnO nanostructured composites are considered novel candidates for various applications in biomedical and photocatalytic studies.
10
Balusamy, Brabu, Burcu Ertit Taştan, Seyda Fikirdesici Ergen, Tamer Uyar i Turgay Tekinay. "Toxicity of lanthanum oxide (La2O3) nanoparticles in aquatic environments". Environmental Science: Processes & Impacts 17, nr 7 (2015): 1265–70. http://dx.doi.org/10.1039/c5em00035a.
Pełny tekst źródłaStreszczenie:
The study demonstrated the ecotoxic potential of lanthanum oxide nanoparticles on fresh-water aquatic microalgae Chlorella sp. and the crustacean Daphnia magna. Lanthanum oxide nanoparticles showed no toxic effects on algae and severe toxic effects on the crustacean. Results may play a vital role in the risk assessment process for exposure of lanthanum oxide nanoparticles in aquatic environments.
11
Lingamdinne, Lakshmi Prasanna, Janardhan Reddy Koduru, Yoon-Young Chang, Seon-Hong Kang i Jae-Kyu Yang. "Facile Synthesis, Characterization, and Adsorption Insights of Lanthanum Oxide Nanorods". Metals 10, nr 8 (24.07.2020): 1001. http://dx.doi.org/10.3390/met10081001.
Pełny tekst źródłaStreszczenie:
This study synthesized lanthanum oxide (La2O3) nanorods to develop a practical approach for the removal of arsenic from groundwater. La2O3 nanorods were synthesized by a simple hydrothermal process followed by calcination at 500 °C and were characterized by spectroscopic and microscopic techniques. To evaluate the adsorption mechanism of La2O3 nanorods, adsorption parameters including solution pH, temperature, equilibrium isotherms, and kinetics for arsenic were studied. The results suggested that the arsenic uptake was a rate-limiting, monolayer adsorption interaction on the La2O3 nanorods homogeneous surface. In addition, it was found that the adsorptive removal behavior of La2O3 for As(V) was sensitive to the initial pH and temperature, and the maximum uptake amount of as prepared La2O3 was found to be 260.56 mg/g of As(V) at pH 6.0 and 25 °C. Furthermore, the uptake capacity of La2O3 nanorods for As(V) increased with temperature. The resultant thermodynamic parameters (ΔG0, ΔH0, and ΔS0) suggested an endothermic adsorption of As(V) on La2O3. The adsorption capacity of La2O3 was higher than that of several reported nanocomposites, suggesting its practical applicability and novelty for As-contaminated wastewater treatment.
12
Lu, Victor M., i Kerrie L. McDonald. "Lanthanum nanoparticles to target the brain: proof of biodistribution and biocompatibility with adjuvant therapies". Nanomedicine 15, nr 22 (wrzesień 2020): 2107–17. http://dx.doi.org/10.2217/nnm-2020-0165.
Pełny tekst źródłaStreszczenie:
Aim: To determine the biodistribution of lanthanum (III) oxide (La2O3) nanoparticle (NP) therapy to the brain and its biocompatibility with radiation therapy (RT) and chemotherapy (CT). Materials & methods: Healthy balb/c nude mice were administered 4 weekly doses of La2O3 NP therapy via tail vein injection. Organ weights and lanthanum concentrations were evaluated. Results: La2O3 NP penetrated the brain. Concentrations were found to peak in the brain at 24 h after injection and persisted at 8 weeks after injection. Neither RT nor CT affected biodistribution. No adverse events or safety concerns in other organs were noted. Conclusion: La2O3 NP can reach the brain to target neurological disease and is biocompatible with RT and CT in a biological system.
13
Zhang, Jie Qiong, Dan Qun Yu, Hei Wong, Kuniyuki Kakushima i Hiroshi Iwai. "Observation of Substrate Silicon Incorporation into Thin Lanthanum Oxide Film during Rapid Thermal Annealing". Advanced Materials Research 1120-1121 (lipiec 2015): 414–18. http://dx.doi.org/10.4028/www.scientific.net/amr.1120-1121.414.
Pełny tekst źródłaStreszczenie:
Lanthanum oxide (La2O3) has been proposed as the promising gate dielectric material for future complementary metal-oxide-semiconductor (CMOS) technology. However, unlike the conventional homopolar materials such as silicon oxide or silicon nitride, La2O3 is more ionic and in particular at the La2O3/Si interface is less thermally stable. This work investigates the chemical and compositional variations of La2O3 thin film on the silicon substrate during rapid thermal annealing by using angle-resolved x-ray photoelectron spectroscopy (ARXPS) measurements. Results show that thermal annealing at temperatures above 500 °C would result in the incorporation of substrate Si atoms deep into the bulk of the La2O3 film and forming silicate phases both at the interface and in the bulk. These effects would result in the characteristic degradation of CMOS devices.
14
Zheng, Kaikui, Chenghui Gao, Fushan He i Youxi Lin. "The Role of Rare Earth Lanthanum Oxide in Polymeric Matrix Brake Composites to Replace Copper". Polymers 10, nr 9 (14.09.2018): 1027. http://dx.doi.org/10.3390/polym10091027.
Pełny tekst źródłaStreszczenie:
The main focus of current research in polymeric matrix brake composites is on searching out a replacement for copper, which has been recently proved to be a hazard to human health and the environment. In this paper, rare earth lanthanum oxide was explored for the replacement of copper in composites. The mechanism of the role of lanthanum oxide in brake composites to replace copper was analyzed. Four series of polymeric matrix brake composites with various amounts of copper (15, 10, 5 and 0 wt %) and rare earth lanthanum oxide (0, 5, 10 and 15 wt %) were developed, in which the copper was gradually replaced by lanthanum oxide in the formula. These series were characterized in terms of physical, thermo-physical and mechanical properties. The results show that lanthanum oxide can be successfully used as a replacement for copper in brake composites. Brake composites with 15 wt % lanthanum oxide that are copper-free are considered optimal, where tribo-properties are considered best. Compared with the addition of copper in brake composites, lanthanum oxide is more conducive to the formation of compacted friction films and transfer films, which is beneficial to the tribological properties of the brake composites. The addition of La2O3 to the brake composites can cause the reaction between La2O3 and Al2O3 to form LaAlO3, and the reaction between Al2O3 and BaSO4 can produce Ba18Al12O36 and Al2SO4 during the friction and wear processes, which can effectively improve the tribological properties of the brake composites at elevated temperature. This research was contributive to the copper-free, metal-free and eco-friendly brake composites.
15
Panić, Stefan V., Marijana R. Pantović Pavlović, Miroslava M. Varničić, Vojin Tadić, Srećko Stopić, Bernd Friedrich i Miroslav M. Pavlović. "Rare-Earth/Manganese Oxide-Based Composites Materials for Electrochemical Oxygen Reduction Reaction". Catalysts 12, nr 6 (12.06.2022): 641. http://dx.doi.org/10.3390/catal12060641.
Pełny tekst źródłaStreszczenie:
The main objective of this research was a systematic development of advanced micro/nanostructured materials based on the most used metal-oxides for ORR and metal-oxides with an extremely low-loading of Pt for comparison. Hybrid composites compared were: MnO2, La2O3, mixed lanthanum manganese oxides (LMO), and mixed lanthanum manganese oxides with reduced platinum load (LMO-Pt). The influence of the reduced amount of noble metal, as well as single oxide activity toward ORR, was analyzed. The complete electrochemical performance of the hybrid materials has been performed by means of CV, LSV, and EIS. It was shown that all synthesized catalytic materials were ORR-active with noticeable reduction currents in O2 saturated 0.1 M KOH. The ORR behavior indicated that the La2O3 electrode has a different mechanism than the other tested electrode materials (MnO2, LMO, and LMO-Pt). The EIS results have revealed that the ORR reaction is of a mixed character, being electrochemically and diffusion controlled. Even more, diffusion is of mixed character due to transport of O2 molecules and the chemical reaction of oxygen reduction. O2 diffusion was shown to be the dominant process for MnO2, LMO, and LMO-Pt electrolytic materials, while chemical reaction is the dominant process for La2O3 electrolytic materials.
16
Mao, Ning, Wensheng Yang, Dehong Chen, Wenli Lu, Xiaowei Zhang, Shiying Chen, Minglei Xu i in. "Effect of Lanthanum Addition on Formation Behaviors of Inclusions in Q355B Weathering Steel". Materials 15, nr 22 (10.11.2022): 7952. http://dx.doi.org/10.3390/ma15227952.
Pełny tekst źródłaStreszczenie:
The effect of lanthanum addition on the formation behaviors of inclusions in Q355B weathering steel was investigated by laboratory experiments and thermodynamic calculations. The results demonstrate that the main inclusions in weathering steel without La addition are large-sized irregular Al2O3 and MnS, with an average size of about 5.35 μm. As La content increases from 0.0075 to 0.0184 wt.%, the dominant inclusions transform from MnS, LaAlO3, and Al2O3-LaAlO3 into MnS, La2O3, and LaAlO3-La2O3. Meanwhile, the average size of inclusions significantly decreases from 3.4 to 2.48 μm and the distribution is more dispersive. When the La content increases to 0.0425 wt.%, the original MnS and Al2O3 inclusions are completely modified into La2O2S and La2O3 but the inclusions demonstrate serious agglomeration and growth. The thermodynamic calculations indicate that Al2O3 and various lanthanum-containing inclusions are formed in the liquid phase. As the La content in molten steel increases from 0 to 0.0425 wt.%, the Al2O3 inclusion is inclined to be modified into lanthanum oxide and lanthanum oxysulfide and the modification process is Al2O3 → LaAlO3 → La2O3 → La2O2S, which is very consistent with the experimental observations.
17
Yuan, Lin, Song Lin Chen, Xue Feng Chen, Xi Jun Liu, Jie Zeng Wang i Xue Tao Yuan. "Spinel and Lanthanum Zirconate Composite for Cement Kiln". Applied Mechanics and Materials 66-68 (lipiec 2011): 1179–86. http://dx.doi.org/10.4028/www.scientific.net/amm.66-68.1179.
Pełny tekst źródłaStreszczenie:
Researching and developing chrome-free refractory becomes a research hotspot at present because hexavalent chromium ions (Cr6+) may lead to environmental hazard. The additives lanthanum oxide (La2O3), effect on mechanism of spinel refractory react with cement clinker, several additives, such as cerium oxide (Ce2O3), titanium dioxide (TiO2), barium oxide (BaO), iron oxide (Fe2O3), are researched in this paper. It indicates that La2O3 is a suitable additive to MgO-MgAl2O4-ZrO2 brick which not only could stabilize phase transition of dicalcium silicate (C2S) in cement, but also do not impair the high-temperature-properties of spinel. The new environmentally friendly material spinel and lanthanum zirconate Composite is an excellent refractory for cement kiln which has high thermal shock resistance, good coating adherence, good corrosion resistance, higher mechanical strength, and longer service life than magnesia-chrome brick when they are used for sintering zone in cement kiln.
18
Li, Yandong, Tongsheng Zhang, Yefeng Feng, Chengjun Liu i Maofa Jiang. "Liquid Regions of Lanthanum-Bearing Aluminosilicates". Materials 13, nr 2 (17.01.2020): 450. http://dx.doi.org/10.3390/ma13020450.
Pełny tekst źródłaStreszczenie:
The Al2O3-SiO2, La2O3-Al2O3, and La2O3-SiO2 binary phase diagrams were estimated by Redlich–Kister expression. La4.67Si3O13 (=La4.67(SiO4)3O) was introduced to improve the existing phase diagrams. The Al2O3-SiO2-La2O3 ternary phase diagram extrapolated by Kohler method was optimized. Then, the liquidus of Al2O3-SiO2-La2O3 system at 1600 °C was compared with Al2O3-SiO2-RE2O3 (RE = Rare Earth Elements) systems and experimental results in other literature. The high temperature experiments were conducted in the tube furnace at 1500 °C. Then the field emission scanning electron microscope (FE-SEM), energy dispersive spectrometer (EDS), and X-ray diffraction (XRD) were employed to verify the calculated liquid region and precipitates phase at 1500 °C. Moreover, the liquidus of binary systems were compared with FactSage results and experiments. The optimized ternary phase diagram shows the relatively reliable region of liquid phase, and it is significant to the seal glass of solid oxide fuel cells and other fields being related to RE containing silicates.
19
Kim, So Jin, Won Kyu Han, Sung Goon Kang, Min Su Han i Young Hun Cheong. "Formation of Lanthanum Hydroxide and Oxide via Precipitation". Solid State Phenomena 135 (luty 2008): 23–26. http://dx.doi.org/10.4028/www.scientific.net/ssp.135.23.
Pełny tekst źródłaStreszczenie:
Lanthanum hydroxide and oxide were prepared by the precipitation method in an aqueous medium at room temperature. The precipitate was examined using thermal analysis, X-ray diffraction and Scanning Electron Microscopy to investigate the phase evaluation and the thermal transformation by decomposition. The as-precipitated powder from the precipitation method was hexagonal La(OH)3. The lanthanum hydroxide was decomposed to oxide in two-steps as La(OH)3 → LaOOH + H2O and 2LaOOH → La2O3 + H2O.
20
Kume, Shoichi, Masaki Yasuoka i Koji Watari. "Effect of Lanthanum Oxide Addition on Dielectric Loss and Microstructure of AlN Ceramics". Key Engineering Materials 320 (wrzesień 2006): 197–200. http://dx.doi.org/10.4028/www.scientific.net/kem.320.197.
Pełny tekst źródłaStreszczenie:
The effect of sintering additives on dielectric loss tangent and microstructure of AlN ceramics have been investigated. Different amounts of Y2O3 and La2O3 were added as sintering additives to AlN powder and pressureless sintering was performed at 1900 °C for 2 h in a flowing nitrogen atmosphere. Bulk densities of sintered AlN were found to be 3.27 and 3.32 Mg·m-3 when Y2O3 contents were 0.5 and 1 mol%, respectively. The bulk densities of AlN-Y2O3 increased with increasing La2O3 content. Densities of 3.41 and 3.42 Mg·m-3 were obtained for 0.5 mol%Y2O3-1 mol%La2O3-AlN and 1 mol%Y2O3-1 mol%La2O3-AlN ceramics respectively. A decrease in tan δ was observed with increase in La2O3 content and a minimum value of 1.3 x 10-3 was obtained for 0.5 mol%La2O3-1 mol%Y2O3-AlN ceramic in the present study.
21
Zhang, Guo Jun, Yi Zhao, Bin Li, Rui Hong Wang, Gang Lui i Jun Sun. "Microstructure and Mechanical Properties of Molybdenum Alloy Strengthened by Lanthanum Oxide and Silicon". Key Engineering Materials 479 (kwiecień 2011): 22–26. http://dx.doi.org/10.4028/www.scientific.net/kem.479.22.
Pełny tekst źródłaStreszczenie:
The molybdenum alloy sheets composite strengthened by silicon and lanthanum oxide were prepared by powder metallurgy technology with Mo-La2O3(0.3wt%) and Si(0, 0.1, 0.3wt%) powders and thermo-mechanically processing. The influences of silicon content on the microstructure and mechanical properties of the final molybdenum alloy sheets were tested and analysized. The results show that the addition of lanthanum oxide and silicon can refine the alloys grain size. The introduction of lanthanum oxide particles can increase the yield strength. Although the molybdenum alloys with 0.3wt% silicon have solid solution strengthening effect, the alloys with 0.1 wt% silicon exhibits obvious solid solution softening effect at room temperature. The strengthening mechanisms are quantitatively assessed, which well explain the increase or decrease in yield strength with respect to grain size, lanthanum oxide particle and silicon solid solution.
22
Lavrynenko, Olena Mykolaivna, Maksym Mykytovych Zahornyi, Valeriia Volodymyrivna Vember, Olesia Yuriivna Pavlenko, Tatyana Fedorovna Lobunets, Olexandr Fedorovych Kolomys, Olga Yurievna Povnitsa i in. "Nanocomposites Based on Cerium, Lanthanum, and Titanium Oxides Doped with Silver for Biomedical Application". Condensed Matter 7, nr 3 (19.07.2022): 45. http://dx.doi.org/10.3390/condmat7030045.
Pełny tekst źródłaStreszczenie:
Nanosized composites CeO2–Ag, La2O3–Ag, and TiO2–Ag are a class of nanomaterials suitable for photocatalysis, optical devices, and photoelectrochemical elements. Further, nanocomposites with several wt.% of silver can be used as creating materials for pathogenic virus inactivation with pandemic-neutralizing potential. Thus, CeO2–Ag, La2O3–Ag, and TiO2–Ag nanocomposites are prospective materials due to their optical and biological activity. In the present work, CeO2–Ag, La2O3–Ag, and TiO2–Ag nanocomposites were synthesized by the co-precipitation method. The morphological and optical properties and the structure of the prepared nanocomposites were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM) with EDX, and nitrogen adsorption-desorption based on BET, Raman spectroscopy, and photoluminescence (PL). Both oxide matrixes corresponded to the cubic crystal lattice with the inclusion of argentum into the crystal lattice of oxides at relative low c(Ag) and reduction of silver on particle surface at 5 wt.% Ag and greater. The CeO2, TiO2, and La2O3 with a concentration of 4 wt.% Ag inhibited the growth processes of prokaryotic cells of E. coli, Bacillus sp., and S. aureus compared to pure oxides. Influenza A virus and herpes completely suppressed reproduction by nanocomposites of CeO2–Ag (2, 5 wt.%) and La2O3–Ag (2, 5 wt.%) action.
23
Su, Jianing, Genqiang Chen, Wei Wang, Han Shi, Shi He, Xiaoyong Lv, Yanfeng Wang, Minghui Zhang, Ruozheng Wang i Hong-Xing Wang. "Electrical characteristics of normally off hydrogen-terminated diamond field effect transistors with lanthanum oxide gate dielectric". Applied Physics Letters 121, nr 16 (17.10.2022): 162103. http://dx.doi.org/10.1063/5.0119899.
Pełny tekst źródłaStreszczenie:
A normally off hydrogen-terminated diamond (H-diamond) metal-oxide-semiconductor field effect transistor (MOSFET) is realized by using lanthanum oxide (La2O3) gate dielectric. The threshold voltage is demonstrated to be −0.797 V, indicating that the La2O3-gated H-diamond MOSFET has normally off characteristics. The normally off mode could be greatly ascribed to the low work function of La2O3. Based on the capacitance–voltage (C–V) curves, the dielectric constant of La2O3 is calculated to be as high as 25.6. Moreover, the small hysteresis voltage extracted from the C–V curves exhibits low trapped charge density in the La2O3 layer. The maximum drain–source current, maximum transconductance, subthreshold swing, effective mobility, current on/off ratio, and sheet hole density of La2O3-gated MOSFET with a gate length of 2 μm are calculated to be −13.55 mA/mm, 4.37 mS/mm, 161 mV/dec, 202.2 cm2/V·s, 108, and 6.53 × 1012 cm−2, respectively. This work will significantly promote the development of normally off H-diamond MOSFET devices.
24
Zahornyi, M. M., O. M. Lavrynenko, O. Yu Pavlenko, O. Yu Povnitsa, L. O. Artiukh, K. S. Naumenko, S. D. Zahorodnia i A. I. Ievtushenko. "The antiviral activity of cerium and lanthanum nanooxides modified with silver". Himia, Fizika ta Tehnologia Poverhni 14, nr 2 (30.06.2023): 262–72. http://dx.doi.org/10.15407/hftp14.02.262.
Pełny tekst źródłaStreszczenie:
Today, the antiviral activity of oxide nanomaterials can be used in the fight against the viral disease COVID-19. It is thought that Ag nanoparticles may bind to the surface glycoprotein of the virus and interfere with the virus’s interaction with epithelial cells, and inhibit virus reproduction by releasing silver ions in the cell. The viruses’ inhibition with RNA (ribonucleic acid) and DNA (deoxyribonucleic acid) genomes by oxide nanocomposites action was presented. In this research, the surface structure of doped CeO2 (La2O3) was studied by nitrogen adsorption-desorption based on BET method. The silver atom’s existence in CeO2 - Ag0 can facilitate the transport of more holes to the surface and can enhance the optical, antivirus activity. The primary particle size of pure cerium dioxide is 7 nm, for CeO2 - Ag composite at 2 and 4 wt. % of silver is 6.5 and 6.9 nm; for La2O3 - Ag 27 and 35 nm, respectively. Cell viability was assessed using an MTT (3-(4,5-Dimethylthiazol 2-yl)-2,5-diphenyltetrazolium bromide) assay after NPs (nanoparticles) exposure, since only viable cells have functional mitochondrial dehydrogenase enzymes that can reduce MTT to formazan. Nanoparticles were non-toxic for BHK-21(Syrian hamster kidney), Hep-2 (Human larynx carcinoma), and MDCK (Canine kidney) cells in concentrations of 10 and 100 μg/ml, while cell viability was within 76÷100 %. La2O3 and CeO2, which contained 4 wt. % of Ag at a concentration of 1000 μg/ml had a lower toxic effect: for BHK-21 cells 68 and 76 % of viable cells, respectively; for Hep-2 - 40 and 36 %, for MDCK - 42 and 48 %; La2O3 and CeO2 with 2 and 5 wt. % of Ag at a concentration of 1000 µg/ml were highly toxic. The level of ВНК-21, Нер-2, and MDCK cells viability was in a range of 7 to 37 %. It has been stated that oxides of cerium and lanthanum have a pronounced virucidal action against the Herpes simplex virus and Influenza A virus by completely inhibiting the development of its cytopathic action. The lanthanum and cerium oxides with 2 and 5 wt. % of silver inhibited the development of the virus’s CPE by more than 5.0 log10 compared to the virus control. The results show that lanthanum and cerium oxides with 2 and 5 wt. % silver have a high virucidal effect against herpes simplex virus type 1. A 1.0÷4.0 log10 reduction in the infectious titer of the Herpes virus synthesized “de novo” in the presence of lanthanum and cerium oxide nanocomposites has been shown.
25
KAFADARYAN, Y. A., S. I. PETROSYAN, G. R. BADALYAN, V. G. LAZARYAN, G. H. SHIRINYAN, N. R. AGHAMALYAN, R. K. HOVSEPYAN, H. S. SEMERJIAN, A. S. IGITYAN i A. M. KUZANYAN. "STRUCTURAL CHARACTERISTICS OF La2O3 THIN FILM GROWN ON LaB6". International Journal of Modern Physics: Conference Series 15 (styczeń 2012): 61–66. http://dx.doi.org/10.1142/s2010194512006964.
Pełny tekst źródłaStreszczenie:
Within the framework of hexagonal lanthanum oxide ( h - La 2 O 3) formation, lanthanum hexaboride film on sapphire substrate ( LaB 6/ Al 2 O 3) was oxidized at different temperatures (700-1000 °C) under reduced atmospheric pressure (1·10-2,1.5·10-1Torr) during 30 min. The composition evolution of La 2 O 3/ LaB 6 structure versus annealing temperature has been studied using XRD, FIR reflectivity spectroscopy, SEM and electron probe X-ray microanalysis (EDS). The annealing of the LaB 6 film at T =700 °C under air pressure of 1·10-2 Torr generates thin La 2 O 3 layer which exhibits as inferred from XRD the hexagonal phase. The hydratation of La 2 O 3/ LaB 6/ Al 2 O 3 in distilled water for 30 min and postannealing at 900 °C under air pressure of 1.5·10-1 Torr transform h - La 2 O 3 into hexagonal La ( OH )3 phase accompanied monoclinic LaO ( OH ) and lanthanum oxide carbonate hydrate species.
26
Subramanian, P., i S. Alwin David. "Biosynthesis of La2O3 Nanoparticles using Lawsonia inermis Leaf Extract". UTTAR PRADESH JOURNAL OF ZOOLOGY 45, nr 18 (3.09.2024): 161–69. http://dx.doi.org/10.56557/upjoz/2024/v45i184434.
Pełny tekst źródłaStreszczenie:
The article explains the biogenesis of lanthanum oxide nanoparticles (La2O3 NPs) utilizing Lawsonia inermis extract as an easy, safe, and efficient approach. The La2O3 NPs were synthesized by reducing La(NO3)3.6H2O with Lawsonia inermis leaf extract as a reducing agent. Fourier-transform infrared spectra were used to determine how the biomolecules in the Lawsonia inermis leaf extract contributed to the synthesis of La2O3 NPs. The UV–visible spectrum of the biosynthesized La2O3 NPs revealed absorption peaks at the La2O3 NPs' absorption maxima, which is 245 nm. As per the scanning electron microscopy investigation, the biosynthesized La2O3 nanoparticles (NPs) with a size of 30 to 60 nm had an uneven shape. EDAX confirmed that La and O were present in the La2O3 NPs. La2O3 NPs were tested for their antibacterial properties Klebsiellapneumoniae and Multi Drug Resistant Staphylococcus Aureus. The antibacterial activity of the biosynthesized La2O3 NPs is mild.
27
Li, Yun Han, Qiu Hong Yang i Shen Zhou Lu. "Fabrication and Characterization of Yttrium Lanthanum Oxide Transparent Ceramics Using Powders Prepared by Different Methods". Advanced Materials Research 299-300 (lipiec 2011): 588–91. http://dx.doi.org/10.4028/www.scientific.net/amr.299-300.588.
Pełny tekst źródłaStreszczenie:
Yttrium Lanthanum Oxide transparent ceramics were fabricated with (Y0.9La0.1)2O3 powders prepared by different methods. The growth characteristics, physical and chemical properties of the powders were investigated. The wet-chemical composite powders’ particle size was inhibited by La2O3 at high temperature treatment, therefore smaller than that of powders by solid-state reaction method. During the solid-state reaction between La2O3 and Y2O3 at temperature of 700~1100°C, La2O3 may have not effectively hindered the particle growth of Y2O3. (Y0.90La0.10)2O3 ceramic fabricated by both powders own smaller grain size and lower porosity than Y2O3 ceramics. The transmittance and sintering performance of Y2O3 ceramics were also improved after adding of La2O3. The powders prepared by both methods could be used to make high transparency ceramics.
28
S. Tabasum, A. Sharma, S. Rani, S. Rani, S. Chaudhary, A. Q. Malik, D. Kumar i T. Deshpande. "PROLIFIC FABRICATION OF LANTHANUM OXIDE WITH GRAPHITIC CARBON/GRAPHENE OXIDE FOR ENHANCING PHOTOCATALYTIC DEGRADATION OF CARBOFURAN FROM AQUEOUS SOLUTION". RASAYAN Journal of Chemistry 16, nr 02 (2023): 740–45. http://dx.doi.org/10.31788/rjc.2023.1628266.
Pełny tekst źródłaStreszczenie:
Carbofuran insecticide is one of the most widely used low-cost carbamate pesticides because it effectively controls pests in agriculture fields and gardens. This study provides experimental results of the photocatalytic detoxification of Carbamate in wastewater using graphitic carbon nitride/GO/La2O3 nanocomposite nanoparticles. Calcination and hydrothermal technique were used to produce g-C3N4/GO/La2O3 nanocomposite. Furthermore, the photocatalytic detoxification of Carbofuran was investigated by numerous factors such as catalyst concentrations, irradiation period, and pH. According to the observation, the photo detoxification efficiency of Carbofuran pesticides rises as time increases. According to this study, g-C3N4/GO/La2O3 nanocomposite outperformed pure forms of g-C3N4, g-C3N4/GO, g-C3N4/La2O3 in degrading Carbofuran up to 80% and photo catalytically making it a potential alternative for wastewater treatment.
29
Xie, Shaojian, Yao Xiao, Lei Huang, Jiaxin Li, Jia Yan, Qian Li, Meng Li i Hongguo Zhang. "The Constructing of the Oxide Phase Diagram for Fluoride Adsorption on La-Fe-Al: A Collaborative Study of Density Functional Calculation and Experimentation". Nanomaterials 14, nr 7 (1.04.2024): 619. http://dx.doi.org/10.3390/nano14070619.
Pełny tekst źródłaStreszczenie:
In recent years, fluoride pollution in water is a problem that has attracted much attention from researchers. The removal of fluoride-containing wastewater by adsorption with metal oxide as an adsorbent is the most common treatment method. Based on this, the effect of the doping ratio of La2O3, Fe2O3, and Al2O3 on the fluoride-removal performance was discussed by constructing a phase diagram. In this study, the adsorption mechanism of nanocrystalline lanthanum oxide terpolymer was investigated by density functional theory calculation and experiment. The optimal pH condition selected in the experiment was three, and the adsorption kinetics of fluoride ions were more consistent with the quasi-second-order kinetic model. The adsorption thermodynamics was more consistent with the Langmuir model. When the La-Fe-Al ternary composite oxides achieved the optimal adsorption efficiency for fluoride ions, the mass synthesis ratio was Al2O3:(Fe2O3:La2O3 = 1:2) = 1:100, resulting in a fluoride ion removal rate of up to 99.78%. Density functional calculations revealed that the La-Fe-Al ternary composite oxides had three important adsorption sites for La, Fe, and Al. Among them, the adsorption capacity for HF was Fe2O3 > La2O3 > Al2O3, and for F− was La2O3 > Al2O3 > Fe2O3. This provided good guidance for designing adsorbents to remove fluoride.
30
Subramanian, Yugeswaran, Ananthapadmanabhan P.V, Paraskevopoulos Konstantinos M. i Akira Kobayashi. "Bioactive and Tribological Behaviour of Atmospheric Plasma Sprayed Hydroxyapatite Coatings Reinforced by Lanthanum Oxide". Frontiers in Advanced Materials Research 1, nr 1 (30.05.2019): 12–17. http://dx.doi.org/10.34256/famr1912.
Pełny tekst źródłaStreszczenie:
Lanthanum oxide (La2O3) reinforced Hydroxyapatite coating was deposited by using unique gas tunnel type plasma spray torch under optimum spraying conditions. The phase and microstructure of the as-prepared powder and coatings were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). In vitro bioactivity of the plasma sprayed lanthanum oxide reinforced hydroxyapatite coatings were investigated by using simulated body fluid solution. Results showed that there was onset of apatite formation on the surface of coatings after 15 days of immersion in SBF, while after 19 days of immersion in SBF it was indicated that a HCAp phase crystallized on their surface. Our studies demonstrate that lanthanum oxide reinforced hydroxyapatite coatings are potentially useful biomaterials with good tribological and bioactive behaviour.
31
Mishra, K. C., I. Osterloh, H. Anton, B. Hannebauer, P. C. Schmidt i K. H. Johnson. "Electronic Structures and Host Excitation of LaPO4, La2O3, and AlPO4". Journal of Materials Research 12, nr 8 (sierpień 1997): 2183–90. http://dx.doi.org/10.1557/jmr.1997.0292.
Pełny tekst źródłaStreszczenie:
We report the electronic structures and associated optical properties of three inorganic oxides, namely lanthanum oxide, aluminum phosphate, and lanthanum phosphate, calculated by the first principles augmented spherical wave (ASW) and full potential linear muffin tin orbital (FP-LMTO) band structure methods, and the self-consistent field Xα scattered wave (Xα SW) molecular orbital cluster approach. Our calculations indicate negligible effect of the choice of exchange correlation potentials on the position, shape, and relative ordering of the energy bands. The ASW energy gaps in lanthanum phosphate and aluminum phosphate agree satisfactorily with the measured values. A comparison of the electronic density of states for an isolated phosphate group from molecular orbital calculation and that of the valance band from the band structure methods indicates that the nature of bonding within the phosphate groups does not change in aluminum and lanthanum phosphates. The states near the top of the valence band and bottom of the conduction band are mostly due to the phosphate bonding and antibonding orbitals, indicating that optical absorption near the band edge involves excitation of electrons from the bonding levels to antibonding levels associated with phosphate groups. This explains why the optical gaps in many rare earth phosphates are nearly equal.
32
Игитян, А., Н. Агамалян, Р. Овсепян, С. Петросян, Г. Бадалян, И. Гамбарян, А. Папикян i Е. Кафадарян. "Отрицательная дифференциальная проводимость структур на основе оксида лантана". Физика и техника полупроводников 54, nr 2 (2020): 117. http://dx.doi.org/10.21883/ftp.2020.02.48915.9280.
Pełny tekst źródłaStreszczenie:
Using e-beam evaporation technique, transparent surface-hydrated lanthanum oxide (OH-La2O3) films with a thickness of 40, 140, and 545 nm were obtained. The electrical and optical characteristics of Al/OH-La2O3/p-Si structures were studied, where aluminum and a silicon substrate with p-type conductivity were used as the upper and lower electrodes, respectively. Negative differential conductivity region in the conductivity–voltage characteristics for the forward bias voltage was found; a possible mechanism of negative differential conductivity is explained by proton transport in hydrogen bonded chains of water molecules at the OH-La2O3 film surface.
33
Mikhailov, G. G., L. A. Makrovets i L. A. Smirnov. "THERMODYNAMICS OF THE PROCESSES OF INTERACTION OF LIQUID METAL COMPONENTS IN Fe – Mg – Al – La – O SYSTEM". Izvestiya Visshikh Uchebnykh Zavedenii. Chernaya Metallurgiya = Izvestiya. Ferrous Metallurgy 61, nr 6 (28.07.2018): 460–65. http://dx.doi.org/10.17073/0368-0797-2018-6-460-465.
Pełny tekst źródłaStreszczenie:
At the present time, rare-earth elements in metallurgy are used in the form of mischmetal – a rare-earth elements natural mixture (with atomic numbers from 57 to 71). It contains about 50 wt. % of cerium. The remaining elements are mainly lanthanum and niobium. The specific composition is determined by the ore deposit. Inconstant composition of the modifier containing rare-earth metals (REM) can significantly reduce its efficiency. Experimentally, for every branded steels composition the ratio of various REMs can’t be selected because of the high costs of obtaining technically pure rare-earth metals. The task of determining the each rare earth element optimum concentrations and complex ligature composition can be solved by thermodynamic modeling. In the framework of thermodynamic modeling, the interaction between magnesium, aluminum and lanthanum with oxygen in liquid iron is presented. And the thermodynamic model of steel deoxidation by these active metals composition is considered. On the basis of available literature data on the phase diagrams of the systems MgO – Al2O3 , MgO – La2O3 and La2O3 – Al2O3 , the coordinates of the invariant equilibria points in the system MgO – La2O3 – Al2O3 were determined. The phase diagram of the system MgO – La2O3 – Al2O3 was constructed. It made possible to establish all phase equilibria realized in the process of deoxidation of steel with magnesium, lanthanum and aluminum and to describe these phase equilibria by chemical reactions equations. The activity of the components in liquid oxide melts was determined using the theory of subregular ionic solutions, which takes into account the dependence of the coordination number of cations on the composition of the oxide melt. The activity of components in metal melts conjugated with oxide systems were determined by Wagner’s theory using the parameters of the first order interaction. Equilibrium constants values for the steel deoxidation reactions are installed indirectly by thermodynamic calculations. On the basis of the obtained data the components solubility surface in the metal melts of Fe – Mg – Al – La – O system was constructed, which allowed to determine the liquid metal composition regions associated with the corresponding oxide phase.
34
Sun, Xinzhe, Peng Guo, Yuanyuan Sun i Yuqian Cui. "Adsorption of Hexavalent Chromium by Sodium Alginate Fiber Biochar Loaded with Lanthanum". Materials 14, nr 9 (26.04.2021): 2224. http://dx.doi.org/10.3390/ma14092224.
Pełny tekst źródłaStreszczenie:
Lanthanun oxide (La2O3) is a lanthanum chemical compound incorporates a sensible anionic complexing ability; however, it lacks stability at a low pH scale. Biochar fibers will give the benefit of their massive space and plethoric uses on the surface to support a metal chemical compound. Herein, wet spinning technology was used to load La3+ onto sodium alginate fiber, and to convert La3+ into La2O3 through carbonization. The La2O3-modified biochar (La-BC) fiber was characterized by SEM, XRD and XPS, etc. An adsorption experiment proved that La-BC showed an excellent adsorption capacity for chromates, and its saturation adsorption capacity was about 104.9 mg/g. The information suggested that the adsorption was in step with both the Langmuir and Freundlich models, following pseudo-second-order surface assimilation mechanics, which showed that the Cr (VI) adsorption was characterized by single-phase and polyphase adsorption, mainly chemical adsorption. The thermodynamic parameters proved that the adsorption process was spontaneous and endothermic. The mechanistic investigation revealed that the mechanism of the adsorption of Cr (VI) by La-BC may include electrostatic interaction, ligand exchange, or complexation. Moreover, the co-existing anions and regeneration experiments proved that the La-BC is recyclable and has good prospects in the field of chrome-containing wastewater removal.
35
Alsubaie, Saba M., Daoud Ali, Bader O. Almutairi, Rafa Almeer i Saud Alarifi. "Evaluation of Cyto - and Genotoxic Influence of Lanthanum Dioxide Nanoparticles on Human Liver Cells". Dose-Response 20, nr 3 (lipiec 2022): 155932582211284. http://dx.doi.org/10.1177/15593258221128428.
Pełny tekst źródłaStreszczenie:
Inorganic nanoparticles are representing an emerging paradigm in molecular imaging probe design. We have determined lanthanum oxide nanoparticles (La2O3 NPs)-induced toxicity on human livers cells for 48 hrs. Before exposure to La2O3 NPs, the size and shape of NPs were confirmed by transmission electron microscope. It was found at 32 ±1.6 nm with a sheet-like morphological structure. The viability of CHANG and HuH-7 cells was reduced as the concentration of La2O3 NPs increased. HuH-7 cells were more sensitive than CHANG cells to La2O3 NPs. We observed production of intracellular ROS in HuH-7 cells was more than CHANG cells and the LPO level was more in CHANG cells than in HuH-7 cells at 50 μg/ml of La2O3 NPs. Glutathione was decreased and catalase was increased at 50 μg/ml of La2O3 NPs. More apoptotic and necrotic cells were observed at 300 μg/ml in HuH-7 cells FACS. DNA damage was observed by the SGCE test and more DNA damage was found in CHANG cells than HuH-7 cells at 300 μg/ml La2O3 NPs over 48 hrs. Thus, study warrants the application of La2O3 NPs in daily life and provides vital information about the toxicity of La2O3 NPs.
36
Sun, Yuan Jun, Guo Jun Zhang, Chao Zuo, Jian Feng Wei i Jun Sun. "Microstructure and Tensile Properties of Oxide Dispersion Strengthened Molybdenum Alloys Prepared by Different Doping Process". Key Engineering Materials 353-358 (wrzesień 2007): 481–84. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.481.
Pełny tekst źródłaStreszczenie:
The oxide lanthanum dispersion strengthened molybdenum alloys were prepared by proprietary powder metallurgy technology, in which the Mo-La2O3 powders were prepared by liquid-liquid doping process which the oxide lanthanum was added to ammonium bi-molybdate solutions as aqueous solutions of La(NO3)3 and liquid-solid doping process which the oxide lanthanum was added to molybdenum oxide solid particles as aqueous solutions of La(NO3)3, respectively. The microstructure and tensile properties of the molybdenum alloys were investigated at room temperature. The results show that the molybdenum alloys all have fine molybdenum grains, and the molybdenum alloy prepared by liquid-solid doping process mainly contain fine oxide lanthanum particles of submicron and nano-sized while the alloy prepared by liquid-liquid doping process mainly contain nano-sized fine oxide lanthanum particles. The molybdenum alloys prepared by liquid-liquid doping process have higher yield strength and ductility than yield-solid doping process. The results of strengthen mechanism analysis show that the high strength of the molybdenum alloys can be advisablely explained by the fine grain strengthening and particles dispersion strengthening mechanism through the Hall–Petch relationship and Orowan model.
37
Nirlakalla, Ravi, R. Ravanamma, K. Muralidhara Reddy i R. Padma Suvarna. "Structure and Dielectric Studies of Lanthanum Oxide Activated Niobium-Barium Titanate for Energy Storage Applications". ECS Transactions 107, nr 1 (24.04.2022): 19505–15. http://dx.doi.org/10.1149/10701.19505ecst.
Pełny tekst źródłaStreszczenie:
A 10 mol% of La2O3 doped niobium-barium titanate (60-y) BaO –(40-x) TiO2 – y Nb2O5 – La2O3x (BTNb10La10) (where x = y = 10), BTNb10 and BTLa10 ferroelectric ceramics were prepared by solid state reaction, those are sintered at temperatures 1000 oC for 8 h and calcined at 1250 oC for 6 h to investigate various properties such as structure, morphology and dielectric that include electric hysteresis. Different phases of the BTNb10La10 ceramics were revealed and identified in XRD profile. La–O bending vibration band was identified at 541 cm-1 in the FTIR spectra of BTNb10La10 samples. A broad phonon vibrational Raman band was identified at 770 cm-1of BTNb10La10 ceramics due to the presence of La2O3. 132, 143 and 148 nm are the average particle sizes revealed in scanning electron microscope (SEM) for BTNb10, BTLa10 and BTNb10La10ferroelectrics, respectively. The recoverable energy storage density (Wrec) of the BTNb10La10 ferroelectric is found to be Wrec = 0.3370 J/cm3 with an energy storage efficiency of η = 94%. The slim and antiferroelectric features of electric hysteresis indicates that the BTNb10La10 ferroelectric could be a potential candidate for energy storage pulsed capacitor applications.
38
Abasaeed, Ahmed, Samsudeen Kasim, Wasim Khan, Mahmud Sofiu, Ahmed Ibrahim, Anis Fakeeha i Ahmed Al-Fatesh. "Hydrogen Yield from CO2 Reforming of Methane: Impact of La2O3 Doping on Supported Ni Catalysts". Energies 14, nr 9 (23.04.2021): 2412. http://dx.doi.org/10.3390/en14092412.
Pełny tekst źródłaStreszczenie:
Development of a transition metal based catalyst aiming at concomitant high activity and stability attributed to distinguished catalytic characteristics is considered as the bottleneck for dry reforming of methane (DRM). This work highlights the role of modifying zirconia (ZrO2) and alumina (Al2O3) supported nickel based catalysts using lanthanum oxide (La2O3) varying from 0 to 20 wt% during dry reforming of methane. The mesoporous catalysts with improved BET surface areas, improved dispersion, relatively lower reduction temperatures and enhanced surface basicity are identified after La2O3 doping. These factors have influenced the catalytic activity and higher hydrogen yields are found for La2O3 modified catalysts as compared to base catalysts (5 wt% Ni-ZrO2 and 5 wt% Ni-Al2O3). Post-reaction characterizations such as TGA have showed less coke formation over La2O3 modified samples. Raman spectra indicates decreased graphitization for La2O3 catalysts. The 5Ni-10La2O3-ZrO2 catalyst produced 80% hydrogen yields, 25% more than that of 5Ni-ZrO2. 5Ni-15La2O3-Al2O3 gave 84% hydrogen yields, 8% higher than that of 5Ni-Al2O3. Higher CO2 activity improved the surface carbon oxidation rate. From the study, the extent of La2O3 loading is dependent on the type of oxide support.
39
Nandiyanto, Asep Bayu, Irine Sofianty, Rofi Fadilah Madani, Adani Ghina Puspita Sari, Fitri Febriyanti, Risti Ragadhita, Rina Maryanti i Eddy Soeryanto Soegoto. "Techno-Economic Analysis of Lanthanum Oxide Nanoparticles Production using Combustion Solution and Hydrothermal Supercritical Water Condition". Jurnal Teknik Industri 23, nr 2 (31.08.2022): 79–92. http://dx.doi.org/10.22219/jtiumm.vol23.no2.79-92.
Pełny tekst źródłaStreszczenie:
Lanthanum oxide (La2O3) nanoparticles are widely applied in various fields and have the potential to be made on a fabrication scope. As a consequence, feasibility studies for generating industries for La2O3 production are required, particularly in developing countries. The purpose of this research was to evaluate and investigate the prospect of the production of La2O3 nanoparticles. This study was carried out to determine whether large-scale La2O3 production using solution combustion (SC) and hydrothermal supercritical water conditions (HSWC) is profitable or not. The analysis method was evaluated based on economic evaluation parameters such as gross profit margin, payback period, and cumulative net present value, while also taking technical aspects into account by designing commercial tools. An economic evaluation was made based on estimates of ideal conditions, such as tax increases, changes in raw materials, sales, workers' salaries, and utility costs. The results of the analysis show that the best method, and has great advantages, was the HSWC method. Based on an engineering perspective, this method produces 4.08 tons of La2O3 in 20 years of production. This study is expected to provide information on the production of La2O3 nanoparticles by comparing the solution combustion method and hydrothermal supercritical water conditions on an industrial scale.
40
Mohd Fudzi, Faznny, Halimah Mohamed Kamari, Amirah Abd Latif i Azlan Muhammad Noorazlan. "Linear Optical Properties of Zinc Borotellurite Glass Doped with Lanthanum Oxide Nanoparticles for Optoelectronic and Photonic Application". Journal of Nanomaterials 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/4150802.
Pełny tekst źródłaStreszczenie:
Enhancing the optical properties of glasses for the sake of optical application in various fields is an ongoing challenge in materials science and technology. Thus, the optical properties of zinc borotellurite glass doped with lanthanum oxide nanoparticles (La2O3 NPs) with the chemical composition of {[(TeO2)0.7(B2O3)0.3]0.7(ZnO)0.3}1−x (La2O3 NPs)x, where x = 0.01, 0.02, 0.03, 0.04, and 0.05 molar fraction, have been investigated. Characterization techniques such as x-ray diffraction, Fourier Transform Infrared Spectroscopy, and Ultraviolet-Visible Spectroscopy are employed to yield the structural properties and optical parameter of the glass. The amorphous nature of the fabricated glasses is confirmed with the presence of a broad hump via XRD diffraction pattern. The decreasing amount of high polarizable nonbridging oxygen as the concentration of La2O3 NPs increases has contributed to the increasing trend of energy band gap in the range of 2.70 to 3.52 eV and decreasing value of refractive index between 2.34 and 2.48. The fabricated glasses that have a higher refractive index than the widely used fiber material, pure silica glass, indicate that zinc borotellurite glass doped with lanthanum nanoparticles is a promising material to be applied as optical fibers.
41
K. Parimala Gandhi, S. Hemalatha i S. Sruthi. "Novel Synthesis and Characterization of Lanthanum oxide Nanoparticles from Nano-sized Lanthanum(III) Compound". Journal of Environmental Nanotechnology 13, nr 2 (1.07.2024): 01–04. http://dx.doi.org/10.13074/jent.2024.06.241538.
Pełny tekst źródłaStreszczenie:
A new nano-sized La (III) compound, La[(N2H4)2{C10H6(3-O)(2-COO)}1.5].H2O (X), was synthesized by the sonochemical method and characterized by field emission scanning electron microscope (FESEM), X-ray powder diffraction (XRD) and elemental analyses. Lanthanum oxide nanoparticles were prepared by direct thermal decomposition of nanostructures in a programmable furnace up to 800 ℃ in ambient atmosphere. The structural characterization was done by powder XRD, and morphological observations by FESEM revealed that the quasi-spherical La2O3 nanoparticles obtained are well crystallized and uniform in both morphology and particle size. The study demonstrates that supramolecular compounds may be suitable precursors for the simple one-pot preparation of nanoscale metal oxide materials with different morphologies.
42
Kale, S. S., K. R. Jadhav, P. S. Patil, T. P. Gujar i C. D. Lokhande. "Characterizations of spray-deposited lanthanum oxide (La2O3) thin films". Materials Letters 59, nr 24-25 (październik 2005): 3007–9. http://dx.doi.org/10.1016/j.matlet.2005.02.091.
Pełny tekst źródła
43
Putanenko, Pavel K., Natalia V. Dorofeeva, Tamara S. Kharlamova, Maria V. Grabchenko, Sergei A. Kulinich i Olga V. Vodyankina. "La2O3-CeO2-Supported Bimetallic Cu-Ni DRM Catalysts". Materials 16, nr 24 (18.12.2023): 7701. http://dx.doi.org/10.3390/ma16247701.
Pełny tekst źródłaStreszczenie:
The present work is focused on nickel catalysts supported on La2O3-CeO2 binary oxides without and with the addition of Cu to the active component for the dry reforming of methane (DRM). The catalysts are characterized using XRD, XRF, TPD-CO2, TPR-H2, and low-temperature N2 adsorption–desorption methods. This work shows the effect of different La:Ce ratios (1:1 and 9:1) and the Cu addition on the structural, acid base, and catalytic properties of Ni-containing systems. The binary LaCeOx oxide at a ratio of La:Ce = 1:1 is characterized by the formation of a solid solution with a fluorite structure, which is preserved upon the introduction of mono- or bimetallic particles. At La:Ce = 9:1, La2O3 segregation from the solid solution structure is observed, and the La excess determines the nature of the precursor of the active component, i.e., lanthanum nickelate. The catalysts based on LaCeOx (1:1) are prone to carbonization during 6 h spent on-stream with the formation of carbon nanotubes. The Cu addition facilitates the reduction of the Cu-Ni catalyst carbonization and increases the number of structural defects in the carbon deposition products. The lanthanum-enriched LaCeOx (9:1) support prevents the accumulation of carbon deposition products on the surface of CuNi/La2O3-CeO2 9:1, providing high DRM activity and an H2/CO ratio of 0.9.
44
Khound, Sagarika, Jayanta K. Sarmah i Ranjit Sarma. "Hybrid La2O3-cPVP Dielectric for Organic Thin Film Transistor Applications". ECS Journal of Solid State Science and Technology 11, nr 1 (1.01.2022): 013007. http://dx.doi.org/10.1149/2162-8777/ac4a7e.
Pełny tekst źródłaStreszczenie:
In this work, we have studied the electrical performance of cross-linked polyvinyl phenol (cPVP) modified lanthanum oxide (La2O3) bilayer dielectric film in pentacene thin film transistors (TFT). A simple spin-coating and room temperature operated cross-linking reaction of the hydroxyl moieties of PVP and the nitrogen groups of PMF were carried out to form the cross-linked PVP. The deposition of a thin 30 nm cPVP layer over the La2O3 layer provided a low leakage current (<10−7 A cm−2), causing a reduction in the interface trap density. Besides, the modified surface properties of the La2O3 layer were favorable for the growth of pentacene organic semiconductors. As a result, the current on-off ratio and the sub-threshold slope was improved from 104 and 1.0 V/decade to 105 and 0.67 V/decade. The La2O3∕cPVP pentacene TFT operated at −10 V also exhibited improvement in the field-effect mobility to 0.71 cm2 Vs−1 from 0.48 cm2 Vs−1 for the single-layer La2O3 (130 nm) device. Thus, our work demonstrates that the rare earth oxide La2O3 with cPVP is an excellent dielectric system in the context of emerging transistors with hybrid polymer gate dielectrics.
45
Liu, Huanyu, Shuang Wang, Jian Liang, Hong Hu, Qingtao Li i Hongrui Chen. "Effect of Lanthanum Oxide on the Microstructure and Properties of Ti-6Al-4V Alloy during CMT-Additive Manufacturing". Crystals 13, nr 3 (17.03.2023): 515. http://dx.doi.org/10.3390/cryst13030515.
Pełny tekst źródłaStreszczenie:
Lanthanum oxide powder was added to improve the microstructure and properties of a Ti-6Al-4V alloy part during cold metal transfer (CMT) based on wire arc additive manufacturing (WAAM). The macrostructure, microstructure and properties of the part were studied by using an optical microscope (OM), scanning electron microscope (SEM), electron backscatter(ed) diffraction (EBSD), microhardness evaluation and a tensile test. The results showed that the β grain size and martensite (α) size were reduced by adding lanthanum oxide powder. The texture intensity of the part also decreased due to the change in microstructure. Accordingly, the microhardness and tensile properties of the part obtained by adding lanthanum oxide were improved. In addition, based on the interdependence theory model, adding La2O3 particles in the molten pool as heterogeneous nucleation points could reduce the distance of XSD, so fine equiaxed β grains can be formed in the deposition layer.
46
Radha, A. V., Sergey V. Ushakov i Alexandra Navrotsky. "Thermochemistry of lanthanum zirconate pyrochlore". Journal of Materials Research 24, nr 11 (listopad 2009): 3350–57. http://dx.doi.org/10.1557/jmr.2009.0401.
Pełny tekst źródłaStreszczenie:
A thermodynamic study was carried out to resolve discrepancies in the enthalpy of formation and related parameters for lanthanum zirconate pyrochlore. The homogeneity field for single phase pyrochlore formation was determined to be ∼33–35 mol% La2O3 at 1500 °C. High-temperature oxide melt drop solution calorimetry was performed in sodium molybdate and lead borate solvents on three compositions ranging from La1.98Zr2.01O7 to La2.07Zr1.95O7. The enthalpy of formation from oxides at 25 °C, ΔH0f,ox, for stoichiometric lanthanum zirconate pyrochlore is −107.3 ± 5.1 kJ/mol, and the standard enthalpy of formation from elements, ΔH0f,el, is −4102.2 ± 6.0 kJ/mol. La2Zr2O7 pyrochlore was found by differential thermal analysis to be stable up to its melting point. The melting point and the fusion enthalpy of La2Zr2O7 pyrochlore were measured as 2295 ± 10 °C and ∼350 kJ/mol, respectively.
47
Chudinovych, Olga, Denys Myroniuk, Liliia Myroniuk, Ihor Danylenko i Olena Olifan. "STRUCTURE, OPTICAL PROPERTIES AND PHOTOCATALYTIC ACTIVIYY OF UNDOPED, La2O3-DOPED ZnO NANOCOMPOSITES". Ukrainian Chemistry Journal 89, nr 10 (24.11.2023): 69–84. http://dx.doi.org/10.33609/2708-129x.89.10.2023.69-84.
Pełny tekst źródłaStreszczenie:
La-doped ZnO nanocomposites with different content of La2O3 (1–5%) were obtained by the Pechini method from their nitrate solutions. The solutions of Zn2+ and La3+ nitrates were preliminary obtained by dissolving of zinc and lanthanum oxides with a content of the main component of 99.99% in nitric acid. The influence of lanthanum doping the on the microstructure, morphology, optical properties and photocatalytic activity of the ZnO nanopowders were examined. The properties of the nanopowders were studied by using X-ray phase analysis, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy. The samples were subjected to X-ray powder diffraction using a DRON-3 diffractometer (Cu-K radiation) at room temperature. The scan angle was 0.05–0.1 ° in the range 2 = 15–90 °. X-ray phase analysis confirms the formation of single phase of La2O3-doped ZnO powders on diffractograms. Raman light scattering and photoluminescence spectra were recorded using a Horiba Jobin‑Yvon T64000 spectrometer equipped with a CCD detector at room temperature in the inverse scattering geometry. According to SEM results, the powders characterized a conglomerate structure. The undoped ZnO has an average particle size of 43 nm, while the average particle size of La3+-doped ZnO ranges from 64 to 80 nm. It was established that the morphology of powder particles primarily depends on the content of La3+ in the material. An increase in the amount of La3+ in zinc oxide leads to an increase in the specific surface area (from 3.8 to 11.8 m2/g). In the photoluminescence spectra of ZnO powders, with increasing La2O3 concentration, bands at 400 nm are observed due to the appearance of impurities that cause of interstitial zinc and zinc vacancy defects and their broadening with a shift to the long-wave region. Photocatalytic properties of ZnO powders doped with lanthanum oxide were investigated using Methyl Orange as a model dye under Osram Ultra-Vitalux lamp (300 W) irradiation. A present result indicates that the obtained powders are potential candidate for the practical application in photocatalysis.
48
Khalil, Khaled D., Sayed M. Riyadh, Mariusz Jaremko, Thoraya A. Farghaly i Mohamed Hagar. "Synthesis of Chitosan-La2O3 Nanocomposite and Its Utility as a Powerful Catalyst in the Synthesis of Pyridines and Pyrazoles". Molecules 26, nr 12 (17.06.2021): 3689. http://dx.doi.org/10.3390/molecules26123689.
Pełny tekst źródłaStreszczenie:
Recently, the development of nanocatalysts based on naturally occurring polysaccharides has received a lot of attention. Chitosan (CS), as a biodegradable and biocompatible polysaccharide, is considered to be an excellent template for the design of a hybrid biopolymer-based metal oxide nanocomposite. In this case, lanthanum oxide nanoparticles doped with chitosan at different weight percentages (5, 10, 15, and 20 wt% CS/La2O3) were prepared via a simple solution casting method. The prepared CS/La2O3 nanocomposite solutions were cast in a Petri dish in order to produce the developed catalyst, which was shaped as a thin film. The structural features of the hybrid nanocomposite film were studied by FTIR, SEM, and XRD analytical tools. FTIR spectra confirmed the presence of the major characteristic peaks of chitosan, which were modified by interaction with La2O3 nanoparticles. Additionally, SEM graphs showed dramatic morphological changes on the surface of chitosan, which is attributed to surface adsorption with La2O3 molecules. The prepared CS/La2O3 nanocomposite film (15% by weight) was investigated as an effective, recyclable, and heterogeneous base catalyst in the synthesis of pyridines and pyrazoles. The nanocomposite used was sufficiently stable and was collected and reused more than three times without loss of catalytic activity.
49
Mikhailov, Gennady G., L. A. Makrovets i O. V. Samoilova. "Phase Equilibria in a Liquid Metal of Fe-La-Ce-O System at 1600 °С". Solid State Phenomena 299 (styczeń 2020): 468–74. http://dx.doi.org/10.4028/www.scientific.net/ssp.299.468.
Pełny tekst źródłaStreszczenie:
Thermodynamic modeling of phase equilibria in a liquid metal of Fe–La–Ce–O system at 1600 °С, using the technique of constructing the solubility surfaces for the components of a metal, was carried out. The calculation technique allowed assessing the depth of liquid iron de-oxidation at a complex use of lanthanum and cerium as deoxidizing agents. Also, diagrams of de-oxidants’ consumption for one ton of liquid oxygen-containing iron were calculated in the course of the work. Carrying out a calculation of the solubility surfaces for the components of a metal required simulation of phase diagrams of the following oxide systems: FeO–La2O3–Ce2O3, FeO–CeO2–La2O3, CeO2–La2O3–Ce2O3. The obtained results might be of interest for optimization of the use of rare-earth metals in steelmaking technology.
50
Liu, Jian Shuang, Fang Fang Zhu, Fei Lu i Lin Zhang. "Effect of Thermal Annealing on La2O3 Films Grown by Plasma Enhanced Atomic Layer Deposition". Advanced Materials Research 1088 (luty 2015): 107–11. http://dx.doi.org/10.4028/www.scientific.net/amr.1088.107.
Pełny tekst źródłaStreszczenie:
A plasma enhanced atomic layer deposition process has been demonstrated for Lanthanum oxide films using La (thd)3 precursor and oxygen plasma. The chemical and electrical properties of La2O3 ultra-thin films on Si (100) substrates before and after post-annealing in N2 ambient have been investigated. X-ray photoelectron spectroscopic revealed that interface reactions take place after annealing process which lead to oxygen insufficiency, as well as the balance band offset decreases with the increase of annealing temperature. The capacitance-voltage and current-voltage characteristics show La2O3 capacitors annealed at 900 °C have negligible hysteresis, smaller interface trap density in comparison with as-deposited samples, but larger flat band voltage and higher gate-leakage current density due to the appearance of oxygen vacancy in the La2O3 films.