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Refinement of Mg2Si in Mg-Al-Si alloys through Ca and Y additions:A novel core-shell structure evolution mechanism and enhanced mechanical properties 认领 引用
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作者 Jinhui Huang Shuhong Liu +3 位作者 Zheyuan Liu Xuezhen Che Martin Friák Yong Du 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2026年第3期328-343,共16页
Comprehensive experimental and theoretical investigations on microstructure and mechanical properties were conducted to explore the refinement of Mg2Si in Mg-Al-Si alloys through the addition of Ca and Y.Alloys of ... Comprehensive experimental and theoretical investigations on microstructure and mechanical properties were conducted to explore the refinement of Mg2Si in Mg-Al-Si alloys through the addition of Ca and Y.Alloys of Mg-Al5.5-Si9.5-Cax(x=0,0.05,0.1,0.15,wt.%)and Mg-Al5.5-Si9.5-Yx(x=0,0.3,0.6,0.9,wt.%)were designed based on the CALPHAD(CALculations of PHAse Diagram)calculations and literature data.With the experimentally determined optimal individual addition of 0.1 wt.%Ca and 0.9 wt.%Y respectively,a crossexperiment involving simultaneous addition of Ca and Y for the refinement of Mg2Si was carried out.The alloy composition with the optimal refinement effect and mechanical properties was identified as Mg-Al5.5-Si9.5-Ca0.1-Y0.6(wt.%).In Y-containing alloys,a novel coreshell structure evolution mechanism of MgSi2Y2//Al4MgY//Mg2Si was proposed based on experimental observation and first principles calculations,revealing MgSi2Y2as the core for the heterogeneous nucleation of Mg2Si. 展开更多
关键词 Mg2Si Core-shell structure Mechanical properties Adsorption Heterogeneous nucleation
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Self-powered horizontally structured n–n heterojunction photodetector based on Si–GaN/β-Ga2O3 for UV detection 认领 引用
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作者 Muzi Li Maolin Zhang +3 位作者 Xueqiang Ji Shan Li Lili Yang Weihua Tang 《Chinese Physics B》 SCIE EI CAS CSCD 2026年第2期639-646,共8页
With the rapid advancement of optoelectronic technology,high-performance photodetectors are increasingly in demand in fields such as environmental monitoring,optical communication,and defense systems,where ultraviolet... With the rapid advancement of optoelectronic technology,high-performance photodetectors are increasingly in demand in fields such as environmental monitoring,optical communication,and defense systems,where ultraviolet detection is critical.However,conventional semiconductor materials suffer from limited UV-visible detection capabilities owing to their narrow bandgaps and high dark currents.To address these challenges,wide-bandgap semiconductors have emerged as promising alternatives.Here,we fabricated a horizontally structured n–n heterojunction photodetector by growingβ-Ga2O3 on Si–GaN via plasma-enhanced chemical vapor deposition.The device exhibits a self-powered photocurrent of 3.5 nA at zero bias,enabled by the photovoltaic effect of the space charge region.Under 254-nm and 365-nm illumination,it exhibits rectification behavior,achieving a responsivity of 0.475 m A/W(0 V,220??W/cm~2 at 254 nm)and 257.6 mA/W(-5 V),respectively.Notably,the photodetector demonstrates a high photocurrent-to-dark current ratio of 10~5 under-5-V bias,highlighting its potential for self-powered and high-performance UV detection applications. 展开更多
关键词 Si–GaN/β-Ga2O3 horizontally structured n–n heterojunction self-powered
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Structure and mechanical properties of ZrO_2-mullite nano-ceramics in SiO_2-Al_2O_3-ZrO_2 system 认领 引用 被引量：6
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作者 梁叔全 谭小平 +1 位作者 李少强 唐艳 《Journal of Central South University of Technology》 2007年第1期1-6,共6页
ZrO2-mullite nano-ceramics were fabricated by in-situ controlled crystallizing from SiO2-Al2O3-ZrO2 amorphous bulk. The thermal transformation sequences of the SiO2-Al2O3-ZrO2 amorphous bulk were investigated by X-ray... ZrO2-mullite nano-ceramics were fabricated by in-situ controlled crystallizing from SiO2-Al2O3-ZrO2 amorphous bulk. The thermal transformation sequences of the SiO2-Al2O3-ZrO2 amorphous bulk were investigated by X-ray diffraction, infrared spectrum, scanning electron microscope and differential scanning calorimetric. And the mechanical properties of the nano-ceramics were studied. The results show that the bulks are still in amorphous state at 900 ℃ and the t-ZrO2 forms at about 950 ℃ with a faint spinel-like phase which changes into mullite on further heating. ZrO2 and mullite become major phases at 1 100 ℃ and an amount of m-ZrO2 occur at the same time. The sample heated at 950 ℃ for 2 h and then at 1 100 ℃ for 1 h shows very dense and homogenous microstructure with ball-like grains in size of 20-50 nm. With the increase of crystallization temperature up to 1 350 ℃, the grains grow quickly and some grow into lath-shaped grains with major diameter of 5 μm. After two-step treatment the highest micro-hardness, flexural strength and fracture toughness of the samples are 13.72 GPa, 520 MPa and 5.13 MPa·m1/2, respectively. 展开更多
关键词 SiO2-Al2O3-ZrO2 system amorphous bulk heat treatment structural change mechanical properties
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Structure and internal stress of Au films deposited on SiO_2/Si(100) and mica by dc sputtering 认领 引用 被引量：4
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作者 Hong Qiu, Jingchun Sun, Yue Tian, Yan Huang, Liqing Pan, Fengping Wang, and Ping WuDepartment of Physics, Applied Science School, University of Science and Technology Beijing, Beijing 100083, China 《Journal of University of Science and Technology Beijing》 2004年第5期415-419,共5页
Au films with a thickness of about 300 nm were deposited on SiO_2/Si(100) andmica substrates by dc sputtering. X-ray diffraction spectroscopy and field emission scanningelectron microscopy were used to analyze the str... Au films with a thickness of about 300 nm were deposited on SiO_2/Si(100) andmica substrates by dc sputtering. X-ray diffraction spectroscopy and field emission scanningelectron microscopy were used to analyze the structure and internal stress of the Au films. Thefirms grown on SiO_2/Si(100) show a preferential orientation of [111] in the growth direction.However the films grown on mica have mixture crystalline orientations of [111], [200], [220] and[311] in the growth direction and the orientations of [200] and [311] are slightly more than thoseof [111] and [220]. An internal stress in the films grown on SiO_2/Si(100) is tensile. For Au filmsgrown on mica the internal stresses in the [111]- and [311]-orientation grains are compressive whilethose in the [200]- and [220]-orientation grains are tensile. Au films grown SiO_2/Si(100) havesome very large grains with a size of about 400 nm and have a wider grain size distribution comparedwith those grown on mica. 展开更多
关键词 gold film mica SiO_2/Si(100) structure internal stress
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DEFORMATION INVESTIGATION ON iPP/SiO_2 COMPOSITES: INFLUENCE OF STRETCHING TEMPERATURE AND PARTICLE SIZE ON MORPHOLOGY EVOLUTION AND CRYSTALLINE STRUCTURE OF THIN FILMS 认领 引用
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作者 Xiu-qin Zhang Qian Xing +2 位作者 Rong-bo Li 王锐 Du-jin Wang 《Chinese Journal of Polymer Science》 SCIE EI CAS CSCD 2013年第2期275-284,共10页
In the present work, structure changes during （SiO2） composites have been investigated systematically stretching of isotactic polypropylene （iPP） and iPP/silicon dioxide The or-form crystal structure of both iPP a... In the present work, structure changes during （SiO2） composites have been investigated systematically stretching of isotactic polypropylene （iPP） and iPP/silicon dioxide The or-form crystal structure of both iPP and iPP/SiO2 composites is destroyed and transforms into the mesophase as the samples are stretched at a low temperature （35℃）, while stretching at high temperatures （90℃ and 120℃） can restrain the appearance of defects and keep the perfection of crystal structure. FTIR results reveal that the stretching temperatures show no obvious difference of the effect on the orientation of pure iPP, however, the orientation of iPP/SiO2 composites is greatly changed by the tensile temperature. In the case of micron-sized SiO2 particles （average particle diameter d 〉 1 μm）, the orientation of the composites is lower than that of pure iPP at all stretching temperatures. The above results suggest that the stretching temperature and the SiO2 particle size have great influence on the structure variation and orientation behavior of iPP/SiO2 composites. 展开更多
关键词 iPP/SiO2 composites Stretching Morphology Structure variation.
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Co Content Dependence of Crystal Structure and Specific Magnetization of Fe1-xCo_x-SiO_2 Granules Prepared by Sol-Gel Method 认领 引用
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作者 Guide TANG Wei CHEN +3 位作者 Jianguo ZHAO Denglu HOU Ying LIU Chengfu PAN and Xiangfu NIETo whom correspondence should be addressed E-mail: dlhou@hebtu.edu.cn 《Journal of Materials Science & Technology》 SCIE EI CAS 1999年第4期390-390,共1页
The Co content dependence of crystal structure and specific magnetization of Fe1-xCox-SiO2granular solid prepared by the sol-gel method have been studied. It is found that the crystal structure, Iattice parameter and ... The Co content dependence of crystal structure and specific magnetization of Fe1-xCox-SiO2granular solid prepared by the sol-gel method have been studied. It is found that the crystal structure, Iattice parameter and specific magnetization of the FeCo alloy particles depend on the Co content. 展开更多
关键词 SiO x)Cox-SiO2 Granules Prepared by Sol-Gel Method Fe Co Content Dependence of Crystal Structure and Specific Magnetization of Fe
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Preparation and upconversion luminescence properties of LaF_3:Yb^(3 +),Er^(3 +) /SiO_2 nanocomposites with core /shell structure 认领 引用
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作者 曲玉秋 李美成 赵连城 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2012年第3期73-76,共4页
LaF^3＋ Yb^3＋ , Er^3＋ nanoparticles were successfully synthesized using solvothermal treatment, and LaF^3＋ Yb^3＋ , Er^3＋/SiO2 core/shell nanoparticles were also prepared with reverse microemulsion technique. The ... LaF^3＋ Yb^3＋ , Er^3＋ nanoparticles were successfully synthesized using solvothermal treatment, and LaF^3＋ Yb^3＋ , Er^3＋/SiO2 core/shell nanoparticles were also prepared with reverse microemulsion technique. The crystal structure, morphology and photoluminescence properties of as-prepared core/shell nanoparticles were in- vestigated by X-ray diffraction, transmission electron microscopy and fluorescence spectrophotometer. The re- sults showed thatLaF^3＋ Yb^3＋ , Er^3＋ nanoparticles are of hexagonal structure and SiO2 shell is amorphous. The size ofLaF^3＋ Yb^3＋ , Er^3＋. nanoparticles is 13 nm and the LaF^3＋ Yb^3＋ , Er^3＋/SiO2 nanoparticles present clearly a core/shell structure with 12 nm shell thickness. The solubility of LaF^3＋ Yb^3＋ , Er^3＋ nanocrystals in water and the biocompatibility are both improved by the SiO2 shell. The upconversion luminescence spectra suggested that the SiO~ shell has small effect on the upconversion luminescence properties of the LaF^3＋ Yb^3＋ , Er^3＋ nanocrys- tals. The core/shell structure LaF^3＋ Yb^3＋ , Er^3＋ /SiO2. nanopartlcles are expected to be used in biological appli- cations. 展开更多
关键词 LaFz ： Yb3 ＋ , Er3 ＋/SiO2 nanocomposites core/shell structure upconversion luminescence
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Interfacial Structure of Nanocrystalline SnO_2 and SiO_2-doped SnO_2 认领 引用 被引量：2
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作者 Yichu WU Yufang ZHENG Deming LIN and Aiguo SUTo whom correspondence should be addressed E-mail:stdp04@zsu.edu.cn 《Journal of Materials Science & Technology》 SCIE EI CAS 1999年第4期388-388,共1页
The study of nanocrystalline SnO2 (n-SnO2) and SiO2-doped SnO2 (n-Si-SnO2) samples pre-pared by the sol-gel process showed that SiO2 doping can effectively restrained the growth of nanocrystalline SnO2 grains, thus im... The study of nanocrystalline SnO2 (n-SnO2) and SiO2-doped SnO2 (n-Si-SnO2) samples pre-pared by the sol-gel process showed that SiO2 doping can effectively restrained the growth of nanocrystalline SnO2 grains, thus improving thermal stability of the materials. 展开更多
关键词 SnO Interfacial Structure of Nanocrystalline SnO2 and SiO2-doped SnO2 SiO
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Theoretical Studies on the Si(001)-SiO_2 Interface Structure 认领 引用 被引量：1
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作者 ZHOU Ming-Xiu YANG Chun +2 位作者 DENG Xiao-Yan YU Wei-Fei LI Jin-Shan 《Chinese Journal of Structural Chemistry》 SCIE CAS 北大核心 2006年第6期647-652,共6页
Novel models （2× 1） of Si（001）-SiO2 interface structure have been established. The method of the first-principle General Gradient Approximation （GGA） is employed to structurally optimize the established the... Novel models （2× 1） of Si（001）-SiO2 interface structure have been established. The method of the first-principle General Gradient Approximation （GGA） is employed to structurally optimize the established theoretical models under the K-point space of periodic boundary condition. The structures after optimization have been analyzed, and the results show that the interfaces present in disordered state and both Si-O-Si and Si=O structures exist. Meanwhile, the bonding of surface structure is analyzed via the graphics of electron localization function（ELF）. 展开更多
关键词 Si/SiO2 DFT interface structure
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Influence of catalyst support structure on ethene/decene metathesis and coke formation over WO_3/SiO_2 catalyst 认领 引用 被引量：1
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作者 Zheng Min Chen Sheng-Li +4 位作者 Zhang Jun-Hui Liu Yan Sang Lei You Ju Wang Xiao-Dong 《Petroleum Science》 SCIE CAS CSCD 2013年第1期112-119,共8页
8wt%WO3/SiO2 metathesis （disproportionation） catalysts with different pore structures were prepared by the incipient-wetness-impregnation method. The as-synthesized catalysts were characterized by N2 adsorpfion-deso... 8wt%WO3/SiO2 metathesis （disproportionation） catalysts with different pore structures were prepared by the incipient-wetness-impregnation method. The as-synthesized catalysts were characterized by N2 adsorpfion-desorption, scanning electron microscopy （SEM）, X-ray diffraction （XRD）, UV-visible diffuse reflectance spectroscopy （DRS） and scanning transmission electron microscopy-high-angle annular dark field （STEM HAADF）. The results of STEM HAADF showed that WO3 species were not uniformly distributed on the SiO2 support. The experimental results of 8wt%WO3/SiO2 performance in ethene/decene metathesis revealed that the catalytic effect of 8wt%WO3/SiO2 catalyst and coke formation over it were closely related to the support pore structure： The 8wt%WO3/SiO2 catalyst with a more complicated pore structure showed better catalytic performance but the coke deposition rate was also faster. 展开更多
关键词 Metathesis WO3/SiO2 catalysts pore structure coke formation
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Fe2O3-SiO2复合气凝胶材料的制备及耐温性能 认领 引用 被引量：2
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作者 侯建业 张忠伦 +2 位作者 付晓晴 王明铭 刘振森 《耐火材料》 CAS 北大核心 2025年第2期133-137,共5页
为了提高SiO2气凝胶在高温下的隔热性能,以溶胶-凝胶两步法制备SiO2前驱体溶液,将遮光剂Fe2O3粉末添加到SiO2前驱体溶液中,结合二氧化碳超临界干燥技术,制备出Fe2O3-SiO2复合气凝胶,探究Fe2O3遮光剂的添... 为了提高SiO2气凝胶在高温下的隔热性能,以溶胶-凝胶两步法制备SiO2前驱体溶液,将遮光剂Fe2O3粉末添加到SiO2前驱体溶液中,结合二氧化碳超临界干燥技术,制备出Fe2O3-SiO2复合气凝胶,探究Fe2O3遮光剂的添加(Fe2O3外加质量分数分别为0、0.2%、0.5%、1.0%和3.0%)对气凝胶的影响。结果表明:1)Fe2O3添加到气凝胶中,不会影响气凝胶的形貌;Fe2O3的添加抑制了材料因高温造成的质量损失,提高了复合材料在高温下的稳定性。2)温度低于800℃时,Fe2O3外加量为0.5%(w)的试样,其热导率最低,隔热性能最好;而在800~1000℃温度下,Fe2O3外加量为1%(w)的试样,其热导率最低,仍保持较好的纳米多孔结构。3)通过控制Fe2O3外加量,可以得到适用于不同温度段的复合气凝胶。 展开更多
关键词 Fe2O3-SiO2复合气凝胶 遮光剂 孔结构 热导率 高温性能
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Morphology and Structure of SiO_2 Film Using Thermal Oxidation Process on(111)Silicon Crystals in Dry Oxygen Atmosphere 认领 引用
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作者 TaokaT. 《Rare Metals》 SCIE EI CAS 1989年第1期32-38,共7页
By means of scanning electron microscope(SEM)and high voltage electron microscope(HVEM)we have observed and analysed morphology and micro-structure of silicon oxide film with different thickness formed on(111)silicon ... By means of scanning electron microscope(SEM)and high voltage electron microscope(HVEM)we have observed and analysed morphology and micro-structure of silicon oxide film with different thickness formed on(111)silicon monocrystal under dry oxygen atmosphere at 1100℃.Compared with their oxidation kinetic curves consisted of three stages,we suggested a mechanism on forming silicon oxide film.According to electron and X-ray diffraction analyses the silicon oxide films consisted of silica with different crystal structure.We also have discussed a stacking fault and a dislocation formed in the Si-Sio_2 interface region simulaneously forming silicon oxide film. 展开更多
关键词 Silicon Crystals in Dry Oxygen Atmosphere Morphology and Structure of SiO2 Film Using Thermal Oxidation Process on SiO
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Structures and electrochemical hydrogen storage performance of Si added A_2B_7-type alloy electrodes 认领 引用 被引量：8
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作者 张羊换 任慧平 +3 位作者 蔡颖 杨泰 张国芳 赵栋梁 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第2期406-414,共9页
In order to ameliorate the electrochemical hydrogen storage performance of La-Mg-Ni system A2B7-type electrode alloys, a small amount of Si was added. The La0.8Mg0.2Ni3.3Co0.2Six （x=0-0.2） electrode alloys were prep... In order to ameliorate the electrochemical hydrogen storage performance of La-Mg-Ni system A2B7-type electrode alloys, a small amount of Si was added. The La0.8Mg0.2Ni3.3Co0.2Six （x=0-0.2） electrode alloys were prepared by casting and annealing. The effects of adding Si on the structure and electrochemical hydrogen storage characteristics of the alloys were investigated systematically. The results indicate that the as-cast and annealed alloys hold multiple structures, involving two major phases of （La, Mg）2Ni7 with a Ce2Ni7-type hexagonal structure and LaNi5 with a CaCu5-type hexagonal structure as well as one residual phase LaNi3. The addition of Si results in a decrease in （La, Mg）2Ni7 phase and an increase in LaNi5 phase without changing the phase structure of the alloys. What is more, it brings on an obvious effect on electrochemical hydrogen storage characteristics of the alloys. The discharge capacities of the as-cast and annealed alloys decline with the increase of Si content, but their cycle stabilities clearly grow under the same condition. Furthermore, the measurements of the high rate discharge ability, the limiting current density, hydrogen diffusion coefficient as well as electrochemical impedance spectra all indicate that the electrochemical kinetic properties of the electrode alloys first increase and then decrease with the rising of Si content. 展开更多
关键词 A2B7-type electrode alloy Si additive structure electrochemical characteristics
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Preparation,structure and luminescence properties of deep red phosphors SrSiN2:Eu^2+ 认领 引用 被引量：2
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作者 陈磊 刘荣辉 +4 位作者 庄卫东 刘元红 胡运生 马小乐 胡斌 《Journal of Rare Earths》 SCIE EI CAS CSCD 2016年第1期30-35,共6页
This paper reported a novel synthetic route to Eu2＋ doped SrSiN2 deep red phosphors for white light-emitting diodes. A series of single-phased and high-efficiency SrSiN2：Eu2＋ red phosphors were synthesized based on... This paper reported a novel synthetic route to Eu2＋ doped SrSiN2 deep red phosphors for white light-emitting diodes. A series of single-phased and high-efficiency SrSiN2：Eu2＋ red phosphors were synthesized based on this method. Their structure, morphology, luminescence, quantum efficiency （QE） and thermal quenching properties were investigated and compared with those of SrSiN2： Eu2＋ prepared by the conventional route. It was found that the addition of a small amount of Si3N4 could promote the formation of SrSiN2 from Sr2SisN8 phase. A highly uniform rod-shaped morphology was obtained based on this method. The X-ray powder diffraction and the Rietveld refinement analysis identified the preferential crystalline orientation growth. Under the blue light excitation, Eu2＋ doped SrSiN2 phosphors showed excellent optical properties. Compared with those prepared by the conventional approaches, the external QE of SrSiN2：Eu2＋ phosphor was greatly improved, allowing it a promising phosphor for white LEDs. 展开更多
关键词 red phosphors nitride quantum efficiency Sr2Si5N8 structure rare earths
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Crystal structure and magnetic properties of Nd(Mn1-xFe_x)_2Si_2 compounds 认领 引用 被引量：2
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作者 陈业青 骆军 +2 位作者 梁敬魁 李静波 饶光辉 《Chinese Physics B》 SCIE EI CAS 2009年第11期4944-4948,共5页
X-ray powder diffraction, resistivity and magnetization studies have been performed on polycrystalline Nd（FexMn1-x）2Si2 （0≤x 〈 1） compounds which crystallize in a ThCr2Si2-type structure with the space group 14/... X-ray powder diffraction, resistivity and magnetization studies have been performed on polycrystalline Nd（FexMn1-x）2Si2 （0≤x 〈 1） compounds which crystallize in a ThCr2Si2-type structure with the space group 14/mmm. The field-cooled temperature dependence of the magnetization curves shows that, at low temperatures, NdFe2Si2 is antiferromagnetic, while the other compounds show ferromagnetic behaviour. The substitution of Fe for Mn leads to a decrease in lattice parameters a, c and unit-cell volume V. The Curie temperature of the compounds first increases, reaches a maximum around x=0.7, then decreases with Fe content. However, the saturation magnetization decreases monotonically with increasing Fe content. This Fe concentration dependent magnetization of Nd（FexMn1-x）2Si2 compounds can be well explained by taking into account the complex effect on magnetic properties due to the substitution of Mn by Fe. The temperature＇s square dependence on electrical resistivity indicates that the curve of Nd（Fe0.6Mn0.4）2Si2 has a quasi-linear character above its Curie temperature, which is typical of simple metals. 展开更多
关键词 Nd（FexMn1-x）2Si2 crystal structure magnetic properties resistivity
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Si掺杂对Fe2P化合物基态结构、磁性和电子结构的影响 认领 引用
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作者 扎西卓玛 卢珊珊 +1 位作者 武晓霞 那日苏 《内蒙古大学学报（自然科学版）》 CAS 2026年第3期262-273,共12页
采用第一性原理计算方法研究了Si掺杂对铁磁态Fe2P相结构稳定性、磁矩、交换作用和电子结构的影响规律。研究发现,随着Si含量的增加,六方相c/a的值持续下降,正交相晶格参数呈现差异性变化。掺杂Si两相的稳定性影响明显,所有体系的形... 采用第一性原理计算方法研究了Si掺杂对铁磁态Fe2P相结构稳定性、磁矩、交换作用和电子结构的影响规律。研究发现,随着Si含量的增加,六方相c/a的值持续下降,正交相晶格参数呈现差异性变化。掺杂Si两相的稳定性影响明显,所有体系的形成焓均为负值,在低浓度时,六方相与正交相能量相近,随着掺杂浓度增大,正交相逐渐变为更稳定的相。体系总磁矩随着掺杂浓度单调增加,不同Fe位点局域磁矩存在明显差异,尤其是在正交相中,磁矩分布范围显著展宽,不同晶位间的磁矩差异更为突出。从原子间距变化发现,Si掺杂可有效调控磁耦合强度,层内铁磁耦合在两种结构中均占主导地位。掺杂导致费米能级发生移动,并考虑自旋-轨道耦合时在特定高对称点处引发显著的能带劈裂。进一步分析表明,Si掺杂影响了Fe-P原子间的p-d轨道杂化,改变了d轨道态密度分布,并调节了两相中Fe-P共价键的强度。 展开更多
关键词 Si掺杂 Fe2P化合物 磁性 交换作用 电子结构
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SiO2取代Al2O3对钙铝硼酸盐玻璃结构及水解行为的影响 认领 引用
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作者 饶文秀 殷先印 +3 位作者 黄翱翔 王衍行 高锡平 何坤 《中国建材科技》 CAS 2025年第6期60-64,69,共5页
钛合金封接玻璃与金属钛润湿性差,导致钛合金封接气密性差。与金属钛浸润性良好的低硅硼酸盐玻璃有望解决钛合金封接气密性的问题,但其耐水性差,将降低钛合金封接的表面绝缘电阻。因此,本研究以CaO-Al2O3-B2O3系统玻璃为研... 钛合金封接玻璃与金属钛润湿性差,导致钛合金封接气密性差。与金属钛浸润性良好的低硅硼酸盐玻璃有望解决钛合金封接气密性的问题,但其耐水性差,将降低钛合金封接的表面绝缘电阻。因此,本研究以CaO-Al2O3-B2O3系统玻璃为研究对象,分析SiO2取代Al2O3过程中玻璃网络结构的变化,及其对玻璃水解行为的影响。研究表明,水解行为由Ca-O-BⅣ结构中Ca2+离子的水化行为开始,接下来B3+的溶出使水解逐步由“横向”转变为深入玻璃网络结构的“纵向”,并在玻璃表面形成“绒毛”结构。Ca-O-Si结构可抑制Ca2+离子的水化行为,使玻璃的水解停留在“横向”阶段,不破坏玻璃内部网络结构。 展开更多
关键词 封接玻璃 CaO-Al2O3-B2O3系统玻璃 Ca-O-Si结构 水解行为
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X-RAY POWDER DIFFRACTION DATA AND STRUCTURE REFINEMENT OF COMPOUND ErNi_2Si_2 认领 引用
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作者 Yan, JL Ou, XL Zeng, LM 《中国有色金属学会会刊：英文版》 1998年第4期91-94,共4页
1INTRODUCTIONTherareearthcompoundsRET2Si2，whereREisarareearthelementandTisatransitionmetalelement，havebeenstudiedwithgreatin?..
关键词 ErNi 2Si 2 X ray powder diffraction Rietveld structure refinement
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掺杂含量对LaMn2Ge2-xSix材料晶体结构及性能的影响 认领 引用
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作者 王萌 《中国高新科技》 2026年第13期158-160,共3页
文章以稀土过渡族金属化合物LaMn2Ge2-xSix材料为研究对象,研究了不同浓度的Si掺杂对材料晶体结构及性能的影响。研究发现,随着Si含量的增加晶格常数的变化近似符合线性递减规律。当X=0.3和0.4时,晶格常数偏离了该规律。其磁... 文章以稀土过渡族金属化合物LaMn2Ge2-xSix材料为研究对象,研究了不同浓度的Si掺杂对材料晶体结构及性能的影响。研究发现,随着Si含量的增加晶格常数的变化近似符合线性递减规律。当X=0.3和0.4时,晶格常数偏离了该规律。其磁性能也产生改变,表现为:螺旋反铁磁态(AFM)向锥形铁磁态(Fmiab)转变的温度(Tc):当X0.3时,随掺杂浓度的提升,其TC温度升高。说明在该化合物中晶格常数与磁转变温度Tc存在密切联系,X=0.3为其转变点。 展开更多
关键词 LaMn2Ge2-xSix Si掺杂 晶体结构 磁结构
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Effect of CO_2 on the structural variation of Na_2WO_4/Mn/SiO_2 catalyst for oxidative coupling of methane to ethylene 认领 引用 被引量：3
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作者 Jia Shi Lu Yao Changwei Hu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2015年第4期394-400,共7页
In this work,the influence of CO2 on the structural variation and catalytic performance of Na2WO4/Mn/Si O2 for oxidative coupling of methane to ethylene was investigated. The catalyst was prepared by impregnation meth... In this work,the influence of CO2 on the structural variation and catalytic performance of Na2WO4/Mn/Si O2 for oxidative coupling of methane to ethylene was investigated. The catalyst was prepared by impregnation method and characterized by XRD,Raman and XPS techniques. Appropriate amount of CO2 in the reactant gases enhanced the formation of surface tetrahedral Na2WO4 species and promoted the migration of O in MOx,Na,W from the catalyst bulk to surface,which were favorable for oxidative coupling of methane. When the molar ratio of CH4/O2/CO2 was 3/1/2,enriched surface tetrahedral Na2WO4 species and high surface concentration of O in MOx,Na,W were detected,and then high CH4 conversion of 33.1% and high C2H4 selectivity of 56.2% were obtained. With further increase of CO2 in the reagent gases,the content of active surface tetrahedral Na2WO4 species and surface concentration of O in MOx,Na,W decreased,while that of inactive species（Mn WO4 and Mn2O3） increased dramatically,leading to low CH4 conversion and low C2H4 selectivity. It could be speculated that Na2WO4 crystal was transformed into Mn WO4 crystal with excessive CO2 added under the reaction conditions. Pretreatment of Na2WO4/Mn/Si O2 catalyst by moderate amount of CO2 before OCM also promoted the formation of Na2WO4 species. 展开更多
关键词 Oxidative coupling of methane CO2 C2H4 Na2WO4/Mn/SiO2catalyst Structural variation
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