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Effects of Additive AlCl_3 on Crystal Phase, Particle Size and Microstructural Parameters of Nanocrystalline TiO_2 Prepared by HF-PCVD 被引量:2
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作者 HaipingXU YanpingSUN XinmouCHEN 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2004年第6期641-643,共3页
Nanocrystalline TiO2 was prepared by high frequency plasma chemical vapor deposition (HF-PCVD). The effects of additive AlCl3 on crystal phase, particle size and microstructurai parameters of TiO2 nanocrystallites wer... Nanocrystalline TiO2 was prepared by high frequency plasma chemical vapor deposition (HF-PCVD). The effects of additive AlCl3 on crystal phase, particle size and microstructurai parameters of TiO2 nanocrystallites were investigated by X-ray diffraction(XRD) and transmission electron microscopy (TEM). The nanocrystallites obtained experimentally are mixture of anatase and rutile, the uniform diameters of particles are about 30 nm. The phase transformation from anatase to rutile was accelerated by AlCl3, and rutile content is increased from 26.7 wt pct to 53.6 wt pct with increasing of addition of AlCl3 from 0.0 wt pct to 5.0 wt pct. The particle size is reduced and the size distribution becomes very narrow. The crystal lattice constants have the trend to decrease, and celi volumes appear as shrinkable. 展开更多
关键词 Additive AlCl_3 Nanocrystalline TiO_2 crystal phase Particle size Microstructural parameters
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Competition between acidic sites and hydrogenation sites in Cu/ZrO_(2) catalysts with different crystal phases for conversion of biomass-derived organics
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作者 Yuewen Shao Tingting Wang +6 位作者 Kai Sun Zhanming Zhang Lijun Zhang Qingyin Li Shu Zhang Guangzhi Hu Xun Hu 《Green Energy & Environment》 SCIE CSCD 2021年第4期557-566,共10页
Oxides with different crystal phases can have important effects on the configuration of surface atoms,which can further affect the distribution of hydrogenation sites and acidic sites as well as the competitions of th... Oxides with different crystal phases can have important effects on the configuration of surface atoms,which can further affect the distribution of hydrogenation sites and acidic sites as well as the competitions of these varied types of catalytic sites.This could be potentially used to tailor the distribution of the products.In this study,zirconium oxides with different crystal phases supported copper catalysts were prepared for the hydrogenation of the biomass-derived furfural,vanillin,etc.The results showed that both calcination temperature and Cu species affected the shift of zirconia from tetragonal phase to the monoclinic phase.Monoclinic zirconia supported copper catalyst can effectively catalyze the hydrogenation of furfural to furfuryl alcohol via hydrogenation route due to its low amount of Brønsted acidic sites,although the surface area and the exposed metallic Cu surface area were much lower than the tetragonal zirconia supported copper catalyst.Zirconia with tetragonal or tetragonal/monoclinic phases supported copper catalysts contain abundant acidic sites and especially the Br?nsted acidic sites,which catalyzed mainly the conversion of furfural via the acid-catalyzed routes such as the acetalization,rather than the hydrogenation.The acidic sites over the Cu/ZrO_(2)catalyst played more predominant roles than the hydrogenation sites in determining the conversion of the organics like furfural and vanillin. 展开更多
关键词 Zirconia supported copper catalyst crystal phase HYDROGENATION Hydrogenation sites Acidic sites
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Crystal Phases and Chemical Stabilities of YSi2 Powders Fabricated from Low and High Purity Si and Y Powders
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作者 Ren Matsushima Mikito Kitayama 《Journal of Materials Science and Chemical Engineering》 2022年第2期18-28,共11页
Y-Si compounds with the composition of Y:Si = 1:2 were fabricated using Yttrium and Silicon raw powders with low and high purity in various atmospheres and temperatures. Although the latest Y-Si phase diagram shows th... Y-Si compounds with the composition of Y:Si = 1:2 were fabricated using Yttrium and Silicon raw powders with low and high purity in various atmospheres and temperatures. Although the latest Y-Si phase diagram shows that the α- and β-YSi<sub>2</sub> phases are the stable phases for the stoichiometric composition of Y:Si = 1:2, the current experimental results suggest that the high temperature phase with the hexagonal structure, β-Y<sub>3</sub>Si<sub>5</sub>, would be the stable phase for this composition, and that the high temperature phase with the orthorhombic structure, β-YSi<sub>2</sub>, would be the meta-stable phase with high oxygen impurity content. It was demonstrated that YSi<sub>2</sub> powders possess much superior chemical stability than Yttrium metal. It was found that the best dispersing solvent was 2-propanol for YSi<sub>2</sub> powder. 展开更多
关键词 YSi2 Yttrium Silicide crystal phase Chemical Stability Oxygen Impurity
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Crystal phase control and ignition properties of HNS/CL-20 composite microspheres prepared by microfluidics combined with emulsification techniques 被引量:1
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作者 Yi Liu Yunyan Guo +6 位作者 Rui Zhu Jinqiang Zhou Zhengxu Lin Kai Han Chongwei An Jingyu Wang Bidong Wu 《Particuology》 SCIE EI CAS CSCD 2024年第2期241-251,共11页
Improved controllability and energy density of ignition agents are of great significance for the devel-opment of energetic composite materials.In this study,droplet microfluidics and emulsification tech-niques were co... Improved controllability and energy density of ignition agents are of great significance for the devel-opment of energetic composite materials.In this study,droplet microfluidics and emulsification tech-niques were combined to prepare HNS/CL-20 composite microspheres with polyglycidyl azide polymer(GAP)as the binder.The influence of binder content on the morphology of microspheres was investi-gated,and the microspheres were characterized and tested for particle size,crystal structure,thermal decomposition,dispersibility,mechanical sensitivity,combustion behavior and detonation performance.The results showed that microspheres prepared with a binder content of 3%had higher sphericity and particle size uniformity.The microspheres retained the crystal structure of both HNS and CL-20(ε-type).Compared with raw HNS,the microspheres had higher apparent activation energy,better safety per-formance,and good dispersibility.The ignition experiments and detonation performance tests show that HNS/CL-20 composite microspheres have excellent ignition performance,obvious combustion flame,and significant energy release effects,which are expected to achieve high energy and high-speed response of the igniter,thus improving the ignition reliability in special environments or systems. 展开更多
关键词 Droplet microfluidics Emulsification technology Energetic materials Composite microspheres crystal phase control IGNITION
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Regulating crystal phase of TiO_(2) to enhance catalytic activity of Ni/TiO_(2) for solar-driven dry reforming of methane
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作者 HE Zhanjun GONG Kun +3 位作者 DAI Yuanyuan NIU Qiang LIN Tiejun ZHONG Liangshu 《燃料化学学报(中英文)》 EI CAS 2024年第9期1203-1213,共11页
Ni/TiO_(2) catalyst is widely employed for photo-driven DRM reaction while the influence of crystal structure of TiO_(2) remains unclear.In this work,the rutile/anatase ratio in supports was successfully controlled by... Ni/TiO_(2) catalyst is widely employed for photo-driven DRM reaction while the influence of crystal structure of TiO_(2) remains unclear.In this work,the rutile/anatase ratio in supports was successfully controlled by varying the calcination temperature of anatase-TiO_(2).Structural characterizations revealed that a distinct TiO_(x) coating on the Ni nanoparticles(NPs)was evident for Ni/TiO_(2)-700 catalyst due to strong metal-support interaction.It is observed that the TiOx overlayer gradually disappeared as the ratio of rutile/anatase increased,thereby enhancing the exposure of Ni active sites.The exposed Ni sites enhanced visible light absorption and boosted the dissociation capability of CH4,which led to the much elevated catalytic activity for Ni/TiO_(2)-950 in which rutile dominated.Therefore,the catalytic activity of solar-driven DRM reaction was significantly influenced by the rutile/anatase ratio.Ni/TiO_(2)-950,characterized by a predominant rutile phase,exhibited the highest DRM reactivity,with remarkable H_(2) and CO production rates reaching as high as 87.4 and 220.2 mmol/(g·h),respectively.These rates were approximately 257 and 130 times higher,respectively,compared to those obtained on Ni/TiO_(2)-700 with anatase.This study suggests that the optimization of crystal structure of TiO_(2) support can effectively enhance the performance of photothermal DRM reaction. 展开更多
关键词 dry reforming of methane photothermal catalysis crystal phase TiO_(2) metal-support interaction
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Effect of Plasma Spheroidization Process on the Microstructure and Crystallographic Phases of Silica, Alumina and Nickel Particles 被引量:8
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作者 胡鹏 闫世凯 +3 位作者 袁方利 白柳杨 李晋林 陈运法 《Plasma Science and Technology》 SCIE EI CAS CSCD 2007年第5期611-615,共5页
During the plasma spheroidization process powders undergo different changes in their microstructures and crystal phases. In this paper, simple calculation of heat transfer between the plasma and a suspended particle w... During the plasma spheroidization process powders undergo different changes in their microstructures and crystal phases. In this paper, simple calculation of heat transfer between the plasma and a suspended particle was performed based on three hypotheses for the purpose of guiding experiments. Experimental investigation of the crystal phases and microstructural changes during the plasma processing was made using silica, alumina and nickel powders as starting materials. It has been revealed from the experimental results that these materials undergo different changes in crystal phases and microstructures, and these changes are essentially determined by the structures, properties and aggregate states of the starting materials. 展开更多
关键词 radio frequency plasma SPHEROIDIZATION MICROSTRUCTURE crystal phase silica alumina NICKEL
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Crystal phase-controlled growth of PtCu and PtCo alloys on 4H Au nanoribbons for electrocatalytic ethanol oxidation reaction 被引量:4
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作者 Jie Wang Jian Zhang +17 位作者 Guigao Liu Chongyi Ling Bo Chen Jingtao Huang Xiaozhi Liu Bing Li An-Liang Wang Zhaoning Hu Ming Zhou Ye Chen Hongfei Cheng Jiawei Liu Zhanxi Fan Nailiang Yang Chaoliang Tan Lin Gu Jinlan Wang Hua Zhang 《Nano Research》 SCIE EI CAS CSCD 2020年第7期1970-1975,共6页
Crystal phase can greatly affect the physicochemical properties and applications of nanomaterials.However,it stil remains a great challenge to synthesize nanostructures with the same composition and morphology but dif... Crystal phase can greatly affect the physicochemical properties and applications of nanomaterials.However,it stil remains a great challenge to synthesize nanostructures with the same composition and morphology but different phases in order to explore the phase-dependent properties and applications.Herein,we report the crystal phase-controlled synthesis of PtCu alloy shells on 4H Au nanoribbons(NRBs),referred to as 4H-Au NRBs,to form the 4H-Au@PtCu core-shell NRBs.By tuning the thickness of PtCu,4H-PtCu and face-centered cubic(cc)phase PICu(cc-PtCu)alloy shells are successtully grown on the 4H-Au NRB cores.This thickness-dependent phase-controlled growth strategy can also be used to grow PtCo alloys with 4H or fcc phase on 4H-Au NRBs.Significantly,when used as electrocatalysts for the ethanol oxidation reaction(EOR)in alkaline media,the 4H-Au@4H-PtCu NRBs show much better EOR performance than the 4H-Au@fcc-PtCu NRBs,and both of them possess superior performance compared to the commercial Pt black.Our study provides a strategy on phase-contolled synthesis of nanomaterials used for crystal phase-dependent applications. 展开更多
关键词 crystal phase 4H hexagonal face-ce ntered cubic ethanol oxidation reaction phase engineering of nanomaterials
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Phase separation-hydrogen etching-derived Cu-decorated Cu-Mn bimetallic oxides with oxygen vacancies boosting superior sodium-ion storage kinetics 被引量:1
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作者 Lin Yan Lingshuo Zong +6 位作者 Qi Sun Junpeng Guo Zhenyang Yu Zhijun Qiao Jiuhui Han Zhenyu Cui Jianli Kang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第5期163-173,I0005,共12页
Understanding the crystal phase evolution of bimetallic oxide anodes is the main concern to profoundly reveal the conversion reaction kinetics and sodium-ion storage mechanisms.Herein,an integrated selfsupporting anod... Understanding the crystal phase evolution of bimetallic oxide anodes is the main concern to profoundly reveal the conversion reaction kinetics and sodium-ion storage mechanisms.Herein,an integrated selfsupporting anode of the Cu-decorated Cu-Mn bimetallic oxides with oxygen vacancies(Ov-BMO-Cu)are in-situ generated by phase separation and hydrogen etching using nanoporous Cu-Mn alloy as selfsacrificial templates.On this basis,we have elucidated the relationship between the phase evolution,oxygen vacancies and sodium-ion storage mechanisms,further demonstrating the evolution of oxygen vacancies and the inhibition effect of manganese oxides as an“anchor”on grain aggregation of copper oxides.The kinetic analyses confirm that the expanded lattice space and increased oxygen vacancies of cycled Ov-BMO-Cu synergistically guarantee effective sodium-ion diffusion and storage mechanisms.Therefore,the Ov-BMO-Cu electrode exhibits higher reversible capacities of 4.04 mA h cm^(-2)at 0.2 mA cm^(-2)after 100 cycles and 2.20 m A h cm^(-2)at 1.0 mA cm^(-2)after 500 cycles.Besides,the presodiated Ov-BMO-Cu anode delivers a considerable reversible capacity of 0.79 m A h cm^(-2)at 1.0 mA cm^(-2)after 60 cycles in full cells with Na_(3)V_(2)(PO_(4))_(3)cathode,confirming its outstanding practicality.Thus,this work is expected to provide enlightenment for designing high-capacity bimetallic oxide anodes. 展开更多
关键词 Sodium-ion storage mechanism Bimetallic oxide anode material crystal phase evolution Oxygen vacancies Kinetic analyses
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Crystal phase engineering of electrocatalysts for energy conversions
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作者 Hui Chen Mingcheng Zhang +7 位作者 Yanfei Wang Ke Sun Lina Wang Zhoubing Xie Yucheng Shen Xindi Han Lan Yang Xiaoxin Zou 《Nano Research》 SCIE EI CSCD 2022年第12期10194-10217,共24页
Crystal phase is an intrinsic structural parameter to determine the physicochemical properties and functionalities of materials.The unconventional phases of materials with distinct atomic arrangements from their therm... Crystal phase is an intrinsic structural parameter to determine the physicochemical properties and functionalities of materials.The unconventional phases of materials with distinct atomic arrangements from their thermodynamically stable phases have attracted enormous attention.Phase engineering has recently made fruitful achievements in electrocatalysis field to optimize the performance of various electrochemical reactions.In this review,theoretical and experimental advances made in phase engineering of electrocatalysts are summarized.First,we introduce basic understanding on crystal phases of catalysts to show the dialectical relationship between bulk phase and surface catalytic layer,and highlight the multiple functions of phase engineering in catalysis studies.We then describe phase-controlled synthesis of materials through various experimental methods such as wet-chemical method,phase transition,and template growth.As a focus,we discuss the wide usage of phase engineering strategy in different kinds of electrocatalytic materials,and particular emphasis is given to establishment of reasonable crystal phase-activity relationship.Finally,we propose several future directions for developing more desirable electrocatalysts by rational crystal phase design. 展开更多
关键词 crystal phase ELECTROCATALYSIS transition metal atomic arrangement energy conversion
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Synthesis of YAG∶Ce^(3+) Phosphor by Polyacrylamide Gel Method and Promoting Action of α-Al_2O_3 Seed Crystal on Phase Formation 被引量:5
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作者 李永绣 李颖毅 +4 位作者 闵宇霖 吴燕利 程昌明 周雪珍 辜子英 《Journal of Rare Earths》 SCIE EI CAS CSCD 2005年第5期517-520,共4页
YAG: Ce^3 + phosphor particles were prepared using polyacrylamide gel method. The structure evolution of powders during annealing process was followed by X-ray diffraction determination. It is found that some interm... YAG: Ce^3 + phosphor particles were prepared using polyacrylamide gel method. The structure evolution of powders during annealing process was followed by X-ray diffraction determination. It is found that some intermediate phases, including θ-Al2O3, YAM and YAP, are formed when calcining polyacrylamide gel, however, the pure YAG phase can be formed directly when calcining polyacrylamide gel with α-Al2O3 as seed crystal. These facts show that the existence of α- Al2O3 seed crystal can block the formation of θ-Al2O3, YAM and YAP, and accelerate its reaction with Y2O3 to form YAG phase directly at lower temperature. The emission peak of prepared YAG : Ce^3 + phosphor is wide with maximum at 550 nm and the exitation band has two peaks, the major one is around at 460 nm, which matches the blue emission of GaN LED and is suitable for the assemble of white LED. Some fluxes can enhance the photoluminescence intensity of phosphor particles, that can be attributed both to the improvement of crystallization processes of YAG and to the stabilization of trivalence cerium ion in YAG:Ce^3 +. 展开更多
关键词 YAG Ce^3 phosphor polyacrylamide gel α-Al2O3 seed crystal phase formation rare earths
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Crystal phase control in two-dimensional materials 被引量:3
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作者 Jialiang Wang Yang Wei +2 位作者 Hai Li Xiao Huang Hua Zhang 《Science China Chemistry》 SCIE EI CAS CSCD 2018年第10期1227-1242,共16页
It is the nature of crystals to exist in different polymorphs. The recent emergence of two-dimensional(2 D) materials has evoked the discovery of a number of new crystal phases that are different from their bulk struc... It is the nature of crystals to exist in different polymorphs. The recent emergence of two-dimensional(2 D) materials has evoked the discovery of a number of new crystal phases that are different from their bulk structures at ambient conditions, and revealed novel structure-dependent properties, which deserve in-depth understanding and further exploration. In this contribution, we review the recent development of crystal phase control in 2 D materials, including group V and VI. transition metal dichalcogenides(TMDs), group IVA metal chalcogenides and noble metals. For each group of materials, we begin with introducing the various existing crystal phases and their structure-related properties, followed by a detailed discussion on factors that influence these crystal structures and thus the possible strategies for phase control. Finally, after summarizing the whole paper, we present the challenges and opportunities in this research direction. 展开更多
关键词 水晶结构 阶段控制 材料 二维 结构相关 贵金属 性质
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Relationship between Multi-Phase Formation and Molecular Structure for Liquid Crystal System 被引量:2
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作者 李振新 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2005年第3期11-13,共3页
4 mechanical model of liquid crystals ( LCs ) was used to explain the phase formation and thermal properties . The LC plusses in the model are micro- machine systems consisting of an ensemble of molecular rotors, an... 4 mechanical model of liquid crystals ( LCs ) was used to explain the phase formation and thermal properties . The LC plusses in the model are micro- machine systems consisting of an ensemble of molecular rotors, and some dynamie parameters in a semi-experiment molecular orbit method. A novel explanation on the multi-phase formation of LC system is obtained. It is found that the value of the critical rotational velueity is a key parameter for the characterization of each homologous series. The dipole moment of the molecules was also discussed. 展开更多
关键词 liquid crystal phase dynamic molecular structure
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CRYSTALLISATION KINETICS AND PHASE TRANSFORMATION BEHAVIOUR OF ELECTROLESS NICKEL-PHOSPHORUS DEPOSIT WITH 6-9wt% PHOSPHORUS CONTENT 被引量:4
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作者 K.G. Keong, W. Sha and S. Malinov (School of Civil Engineering, The Queen’s University of Belfast, Belfast BT7 1NN, UK) 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2001年第6期419-424,共6页
Crystallisation kinetic and phase transformation behaviour of the electroless nickel-phosphorus deposit with 6-9wt% phosphorus content were studied. The deposit was heated in the differential scanning calorimetry (DSC... Crystallisation kinetic and phase transformation behaviour of the electroless nickel-phosphorus deposit with 6-9wt% phosphorus content were studied. The deposit was heated in the differential scanning calorimetry (DSC) apparatus to 300℃-800℃ at 20℃/min, followed by the X-ray diffraction (XRD) analysis. The sequence of crystallisation process was: mixture of amorphous and microcrystalline nickel phases → intermediate metastable, f. c. c. nickel and stable N13P phases → f. c. c. nickel and stable Ni3P phases. Preferred orientation of nickel {200} plane was developed after the heating processes. Activation energy of crystallisation process was determined from the DSC analyses at 5-50℃/min. Crystallisation temperatures were found increased with increasing heating rate. 展开更多
关键词 coating crystalLIZATION NICKEL phase transitions PHOSPHORUS X-ray diffraction
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Mechanical model study of relationship of molecular configuration and multiphase in liquid crystal materials 被引量:3
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作者 马恒 孙瑞芝 李振新 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第5期1009-1014,共6页
A mechanical model of liquid crystals (LCs) is applied to study the polymorphism of homologous series of terphenyl compounds. With a senti-experimental molecular orbit method, we calculate the moment of inertia whic... A mechanical model of liquid crystals (LCs) is applied to study the polymorphism of homologous series of terphenyl compounds. With a senti-experimental molecular orbit method, we calculate the moment of inertia which represents the rotation state to describe the phase transition temperature obtained from experimental data. We propose a novel explanation of the phase sequence or polymorphism of LC materials using the two key parameters, the moment of inertia and critical rotational velocity. The effect of molecular polarity on the appearance of liquid crystalline is also discussed. 展开更多
关键词 mechanical model liquid crystal MULTI-phase moment of inertia
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Effects of Ru on the microstructure and phase stability of a single crystal superalloy 被引量:8
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作者 Zhen-xue Shi Jia-rong Li Shi-zhong Liu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2012年第11期1004-1009,共6页
Two experimental single crystal superalloys, the Ru-free alloy and the Ru-containing alloy with [001 ] orientation, were cast in a directionally solidified furnace, while other alloying element contents were kept unch... Two experimental single crystal superalloys, the Ru-free alloy and the Ru-containing alloy with [001 ] orientation, were cast in a directionally solidified furnace, while other alloying element contents were kept unchanged. The effects of Ru on the microstructure and phase stability of the single crystal superalloy were investigated, y' directional coarsening and rafting were observed in the Ru-free alloy and Ru-containing alloy after long-term aging at 1070~C for 800 h. Needle-shaped o topologically close packed (TCP) phases precipitated and grew along the fixed direction in both the alloys. The precipitating rate and volume fraction of TCP phases decreased significantly by adding Ru. The compositions ofy and y' phases measured using an energy-dispersive X-ray spectroscope (EDS) in transmission electron microscopy (TEM) analysis showed that the addition of Ru lessened the partition ratio of TCP forming elements, Re, W and Mo, and decreased the satu- ration degrees of these elements in y phase, which can enable the Ru-containing alloy to be more resistant to the formation of TCP phases. It is indicated that the addition of Ru to the Ni-based single crystal superalloy with high content of the refractory alloying element can enhance phase stability. 展开更多
关键词 SUPERALLOYS nickel alloys single crystals RUTHENIUM MICROSTRUCTURE phase stability
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Bichromatic coherent random lasing from dye-doped polymer stabilized blue phase liquid crystals controlled by pump light polarization 被引量:3
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作者 王雷 王萌 +3 位作者 杨明朝 石丽洁 邓罗根 杨槐 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第9期99-104,共6页
In this paper,we investigate the bichromatic coherent random lasing actions from the dye-doped polymer stabilized blue phase liquid crystals.Two groups of lasing peaks,of which the full widith at half maximum is about... In this paper,we investigate the bichromatic coherent random lasing actions from the dye-doped polymer stabilized blue phase liquid crystals.Two groups of lasing peaks,of which the full widith at half maximum is about 0.3 nm,are clearly observed.The shorter-and longer-wavelength modes are associated with the excitation of the single laser dye(DCM) monomers and dimers respectively.The experimental results show that the competition between the two groups of the lasing peaks can be controlled by varying the polarization of the pump light.When the polarization of the pump light is rotated from 0?to 90?,the intensity of the shorter-wavelength lasing peak group reduces while the intensity of the longer-wavelength lasing peak group increases.In addition,a red shift of the longer-wavelength modes is also observed and the physical mechanisms behind the red-shift phenomenon are discussed. 展开更多
关键词 bichromatic emission random lasing blue phase liquid crystals
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Electrically tunable holographic polymer templated blue phase liquid crystal grating 被引量:2
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作者 何正红 陈超平 +7 位作者 朱吉亮 袁亚超 李燕 胡伟 李潇 李洪婧 陆建刚 苏翼凯 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第6期328-333,共6页
In this paper, we demonstrate an alternative approach to fabricating an electrically tunable holographic polymer tem- plated blue phase liquid crystal grating. This grating is obtained by preforming a polymer template... In this paper, we demonstrate an alternative approach to fabricating an electrically tunable holographic polymer tem- plated blue phase liquid crystal grating. This grating is obtained by preforming a polymer template comprised of periodic fringes, and then refilling it with a blue phase liquid crystal. Compared with conventional holographic polymer dispersed liquid crystal gratings, our grating can remarkably reduce its switching voltage from 200 V to 43 V while maintaining a sub-millisecond response time. The holographic polymer templated blue phase liquid crystal (HPTBPLC) grating is free from electrode patterning, thus leading to a lower cost and more flexible applications. 展开更多
关键词 holographic polymer dispersed liquid crystal blue phase phase grating
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Phase transformation and nanograting structure on TiO2 rutile single crystal induced by infrared femtosecond laser 被引量:1
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作者 马洪良 杨俊毅 +1 位作者 鲁波 马国宏 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第11期3328-3331,共4页
In this paper, TitaiJum dioxide (TiO2) rutile single crystal was irradiated by infrared femtosecond laser pulses with repetition rate of 250 kHz. For a P-polarized femtosecond laser, the periodic nanograting structu... In this paper, TitaiJum dioxide (TiO2) rutile single crystal was irradiated by infrared femtosecond laser pulses with repetition rate of 250 kHz. For a P-polarized femtosecond laser, the periodic nanograting structure on the ablation crater surface was formed . The periodicity is much less than the laser wavelength. The direction of nanograting alignment depends on the polarization laser beam. Micro-Raman spectra show that the intensity of Eg Raman vibrating mode of rutile phase increases and that of Alg Raman vibrating mode decreases apparently within the ablation crater. With the increase of irradiation time and laser average power, the Raman vibrating modes of anatase phase emerged. Rutile phase of TiO2 single crystal is partly transformed into anatase phase. 展开更多
关键词 infrared femtosecond laser titanium dioxide single crystal phase transformation micro-Raman spectroscopy
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Solid-phase Crystallization of Amorphous Silicon Films by Rapid Thermal Annealing 被引量:5
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作者 JINRui-min LUJing-xiao LIRui WANGHai-yan FENGTuan-hui 《Semiconductor Photonics and Technology》 CAS 2005年第1期37-39,共3页
The morphous silicon films prepared by PECVD at substrate temperatures of 30℃ have been crystallized by rapid thermal annealing method, the budget of time-temperature in the annealing process is 600℃ for 120s,... The morphous silicon films prepared by PECVD at substrate temperatures of 30℃ have been crystallized by rapid thermal annealing method, the budget of time-temperature in the annealing process is 600℃ for 120s, 850℃ for 120s, and 950℃ for 120s. The results indicate the crystallization at 850℃ and 950℃ are better as shown in micro-Raman scattering and scanning electronic microscope. 展开更多
关键词 固相晶化 非晶硅 快速热退火 PECVD
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A phase-field model for simulating various spherulite morphologies of semi-crystalline polymers 被引量:5
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作者 王晓东 欧阳洁 +1 位作者 苏进 周文 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第10期387-393,共7页
A modified phase-field model is proposed for simulating the isothermal crystallization of polymer melts. The model consists of a second-order phase-field equation and a heat conduction equation. It obtains its model p... A modified phase-field model is proposed for simulating the isothermal crystallization of polymer melts. The model consists of a second-order phase-field equation and a heat conduction equation. It obtains its model parameters from the real material parameters and is easy to use with tolerable computational cost. Due to the use of a new free energy functional form, the model can reproduce various single crystal morphologies of polymer melts under quiescent conditions, including dendritic, lamellar branching, ring-banded, breakup of ring-banded, faceted hexagonal, and spherulitic structures. Simulation results of isotactic polystyrene crystals demonstrate that the present phase-field model has the ability to give qualitative predictions of polymer crystallization under isothermal and quiescent conditions. 展开更多
关键词 phase-FIELD crystallization polymer DENDRITIC LAMELLAR ring-banded
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