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Homogeneous Plastic Flow of Fully Amorphous and Partially Crystallized Zr_(41.2)Ti_(13.8)Cu_(12.5)Ni_(10)Be_(22.5) Bulk Metallic Glass 被引量:4
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作者 Q.WANG J.J.Blandin +2 位作者 M.Suery B.Van de Moortele J.M.Pelletier 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2003年第6期557-560,共4页
The homogeneous plastic flow of fully amorphous and partially crystallized Zr(41.2)Ti(13.8)Cu(12.5)Ni(10)Be(22.5) bulk metallic glass (Vitl) has been investigated by compression tests at high temperatures in supercool... The homogeneous plastic flow of fully amorphous and partially crystallized Zr(41.2)Ti(13.8)Cu(12.5)Ni(10)Be(22.5) bulk metallic glass (Vitl) has been investigated by compression tests at high temperatures in supercooled liquid region. Experimental results show that at sufficiently low strain rates, the supercooled liquid of the fully amorphous alloy reveals Newtonian flow with a linear relationship between the flow stress and strain rate. As the strain rate is increased, a transition from linear Newtonian to nonlinear flow is detected, which can be explained by the transition state theory. Over the entire strain rate interval investigated, however, only nonlinear flow is present in the partially crystallized alloy, and the flow stress for each strain rate is much higher. It is found that the strain rate-stress relationship for the partially crystaltized alloy at the given temperature of 646 K also obeys the sinh law derived from the transition state theory, similar to that of the initial homogeneous amorphous alloy. Thus, it is proposed that the flow behavior of the nanocrystalline/amorphous composite at 646 K is mainly controlled by the viscous flow of the remaining supercooled liquid. 展开更多
关键词 Homogeneous plastic flow Zr41.2Ti13.8Cu12.5Ni10Be22.5 amorphous alloy Partially crystallized amorphous alloy
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C–C formation mediated by photoinduced electrons from crystallized carbon nitride nanobelts under visible light irradiation 被引量:1
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作者 Qiaohui Jia Sufen Zhang Quan Gu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2019年第3期152-161,共10页
Crystal structure and crystallinity of carbon nitride support, size and dispersity of active-metal nanoparticles(NPs), and surface engineering of composites have great roles in generation and separation of photogenera... Crystal structure and crystallinity of carbon nitride support, size and dispersity of active-metal nanoparticles(NPs), and surface engineering of composites have great roles in generation and separation of photogenerated charge carries and photocatalyzed organic reactions for the conversion of solar energy into chemical energy. Herein, we deposited well-dispersed Pd NPs with small size on crystallized carbon nitride(CN–C) to construct a Schottky-type Pd/CN–C hybrid for photocatalyzed Ullmann C–C homocoupling of aryl halides under visible light irradiation at room temperature. Compared to Pd NPs supported g-C_3N_4(Pd/g-C_3N_4), Pd/CN–C exhibits excellent visible light photocatalytic activity for Ullmann C–C coupling of aryl halides due to high crystallinity of CN–C support, high dispersion and smaller size of Pd NPs, and the interfacial heterojunction of Pd/CN–C. Upon visible light irradiation, more photogenerated electrons from CN–C flow across the Schottky junction to metallic Pd and trigger the Ullmann C–C coupling of aryl halides. The photogenerated holes on CN–C surface are captured by a protic solvent(such as EtOH). In the presence of base K_2CO_3, the solvent undergoes dissociation, dehydrogenation, and finally can be oxidized by captured photogenerated holes. Moreover, Pd/CN–C has general applicability for various substrates and shows excellent stability and reusability for more than nine cycles. 展开更多
关键词 crystallized carbon NITRIDE Pd nanoparticles PHOTOCATALYST C–C coupling ULLMANN REACTION
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Influence of High Temperature Treatment on the Performance of Nickel-Induced Laterally Crystallized Thin Film Transistors
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作者 秦明 樊路加 +1 位作者 VincentPoon C.Y.Yuen 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2002年第6期571-576,共6页
Well known for their good performance,thin film transistors (TFTs) with active layers which were nickel induced laterally crystallized,are fabricated by conventional process of dual gate CMOS.The influence of pre h... Well known for their good performance,thin film transistors (TFTs) with active layers which were nickel induced laterally crystallized,are fabricated by conventional process of dual gate CMOS.The influence of pre high temperature treatment of device fabrication on the performance of TFTs is also investigated.The experiment shows that the high temperature treatment affects the performance of the devices strongly.The best performance is obtained by adopting pre treatment of 1000℃.The mobility of 314cm 2/(V·s) is obtained at NMOS TFTs with pre treatment of 1000℃,which is 10% and 22% higher than that treated at 1100℃ and without pre high temperature treatment,respectively.A maximum on/off current ratio of 3×10 8 is also obtained at 1000℃.Further investigation of uniformity verifies that the result is reliable. 展开更多
关键词 nickel induced lateral crystallization thin film transistor high temperature treatment
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Characterization of recrystallized itraconazole prepared by cooling and anti-solvent crystallization 被引量:2
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作者 Pornsak Sriamornsak Kanokporn Burapapadh 《Asian Journal of Pharmaceutical Sciences》 SCIE CAS 2015年第3期230-238,共9页
The objective of the present study was to alter the crystal habit of itraconazole(ITZ)by cooling and anti-solvent crystallization and characterize its properties.ITZ was recrystallized in different solvents and the ef... The objective of the present study was to alter the crystal habit of itraconazole(ITZ)by cooling and anti-solvent crystallization and characterize its properties.ITZ was recrystallized in different solvents and the effects of each solvent on morphology of crystals,dissolution behavior and solid state of recrystallized drug particles were investigated.The results revealed that ITZ crystals recrystallized by cooling and anti-solvent crystallization showed the different crystal habits from the untreated ITZ.Using cooling crystallization tended to provide needle-shaped crystals while the crystals obtained from anti-solvent crystallization showed more flaky,plate shape.This indicated the importance of preparation method on nucleation and crystal growth.No change in drug polymorphism was observed,according to determination of thermal property and crystalline state by differential scanning calorimetry and powder X-ray diffractometry,respectively.The recrystallized ITZ showed higher drug dissolution than untreated ITZ and the highest drug dissolution was observed from the samples recrystallized in the presence of PEG 200,which provided the small plate-shaped crystals with tremendously increased in surface area.However,the increasing of drug dissolution is relatively small,therefore,further development may be required. 展开更多
关键词 ITRACONAZOLE Poorly water-soluble drug Cooling crystallization Anti-solvent crystallization
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Crystallization of amorphous silicon beyond the crystallized polycrystalline silicon region induced by metal nickel
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作者 Dongli Zhang Mingxiang Wang +1 位作者 Man Wong Hoi-Sing Kwok 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第1期353-356,共4页
Crystallization of amorphous silicon(a-Si) which starts from the middle of the a-Si region separating two adjacent metal-induced crystallization(MIC) polycrystalline silicon(poly-Si) regions is observed. The cry... Crystallization of amorphous silicon(a-Si) which starts from the middle of the a-Si region separating two adjacent metal-induced crystallization(MIC) polycrystalline silicon(poly-Si) regions is observed. The crystallization is found to be related to the distance between the neighboring nickel-introducing MIC windows. Trace nickel that diffuses from the MIC window into the a-Si matrix during the MIC heat-treatment is experimentally discovered, which is responsible for the crystallization of the a-Si beyond the MIC front. A minimum diffusion coefficient of 1.84×10^-9cm^2/s at 550℃ is estimated for the trace nickel diffusion in a-Si. 展开更多
关键词 metal-induced crystallization POLY-SI NICKEL diffusion coefficient
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Effect of Electrostatic Reduced Gravity Environment on the Crystallographic Parameters of Melt Crystallized Polypropylene
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作者 XIAO Xue-shan DONG Yuan-da +5 位作者 MO Zhi-shen ZHU Ming-yuan WANG Xian-hong QIAO Xiu-ying WANG Qing XU Hui 《Advances in Manufacturing》 SCIE CAS 1999年第4期336-338,共3页
An electrostatic reduced gravity device was developed and used specially for the study of the melt crystallization of polypropylene. The crystal structure of melt crystallized polypropylene prepared under the reduc... An electrostatic reduced gravity device was developed and used specially for the study of the melt crystallization of polypropylene. The crystal structure of melt crystallized polypropylene prepared under the reduced gravity environment was investigated by using X ray diffraction. The experiment results show that the crystal structure of the polypropylene is strongly dependent on the gravity applied to the sample during solidification. It is found that the crystallographic parameters a and b increase markedly with reduced gravity ratio, while the value of c increases mildly. 展开更多
关键词 reduced gravity ELECTROSTATIC POLYPROPYLENE CRYSTALLIZATION
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Mössbauer Spectroscopy and X-Ray Diffraction Studies of the Phase Composition of Crystallized Nd_(x)Fe_(81.5-x)B_(18.5) Alloys with 7 ≤ x ≤15
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作者 CHENG Zhao-hua SHEN Bao-gen +5 位作者 ZHANG Jun-xian MAO Ming-xi SUN Ji-jun YANG Chun-li LI Fa-shen ZHANG Yi-de 《Chinese Physics Letters》 SCIE CAS CSCD 1997年第5期387-390,共4页
The phase composition of melt-spun Nd-Fe-B with intermediate and high Nd concentrations has been studied by Mössbauer effect.Based on the knowledge of the ^(57)Fe hyperfine parameters for Nd_(2)Fe_(14)B,Nd_(2)Fe_... The phase composition of melt-spun Nd-Fe-B with intermediate and high Nd concentrations has been studied by Mössbauer effect.Based on the knowledge of the ^(57)Fe hyperfine parameters for Nd_(2)Fe_(14)B,Nd_(2)Fe_(23)B_(3),and Nd_(1.1)Fe_(4)B_(4),the phases produced during annealing Nd-Fe-B amorphous alloys can be identified.It is found that the Nd_(x)Fe_(81.5-x)B_(18.5) samples with 7≤x≤9 contain the Nd_(2)Fe_(23)B_(3) metastable phase and the Nd1.1Fe4B4 paramagnetic phase.The body-centered-cubic structure of Nd_(2)Fe_(23)B_(3) cannot generate the hard magnetic properties.The samples with 12≤x≤15 consist of the Nd_(2)Fe_(14)B hard magnetic phase and the Nd1.1Fe4B4 paramagnetic phase.The large coercivity for the high Nd content Nd-Fe-B originates from the very fine size of Nd_(2)Fe_(14)B grains below the particle size of the single domain,which may contribute to a pinning effect of domain wall. 展开更多
关键词 PHASE SSBAUER CRYSTAL
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Synthesis and Molecular Structure of 3-(p-Methoxyphenyl)-4-hydroxymethyl-6-bromo-7-hydroxycoumarin Co-crystallized with Methanol
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作者 蒋皓 邹昊 +1 位作者 夏鹏 张倩 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2008年第12期1423-1426,共4页
The title compound, C18H17BrO6 (Mr = 409.23), was synthesized as angiogenesis inhibitor and structurally characterized by ^1H-NMR, ^13C-NMR, MS, elemental analysis and X-ray single-crystal diffraction. Structure ana... The title compound, C18H17BrO6 (Mr = 409.23), was synthesized as angiogenesis inhibitor and structurally characterized by ^1H-NMR, ^13C-NMR, MS, elemental analysis and X-ray single-crystal diffraction. Structure analysis indicates that the title compound is of triclinic, space group P1^-, with a = 8.100(3), b = 10.536(4), c = 11.689(5)A, a = 67.405(7), βl = 69.736(3), γ = 88.510(5)°, V = 857.3(5) A^3, Z = 2, Dc = 1.585 g/cm^3, μ = 2.429 mm^-1, F(000) = 416, the finial R = 0.0356 and wR = 0.0929 for 2541 observed reflections. The bond lengths of C(7)-C(16) proved that the title compound possesses coumarin rather than flavone scaffold. 展开更多
关键词 COUMARIN crystal structure angiogenesis inhibitor
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EFFECT OF PRESSURE ON CRYSTALLIZATION CHARACTERISTICS AND CRYSTALLIZED MICROSTRUCTURE OF AMORPHOUS Al_(85)Ni_(10)Y_(5) ALLOY
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作者 Jiang Xiangyang Chen Zhenhua Zhou Duosan 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 1996年第1期80-84,共5页
The crystallization behaviour of amorphous Al_(85)Ni_(10)Y_(5) alloy under high pressure was investigated.Results showed that the amorphous state can be preserved when the alloy is treated under high pressure at tempe... The crystallization behaviour of amorphous Al_(85)Ni_(10)Y_(5) alloy under high pressure was investigated.Results showed that the amorphous state can be preserved when the alloy is treated under high pressure at temperature below 325℃,the polytropic crystallization takes place when the alloy is treated at 325〜520 ℃ and 3〜6GPa for 1 min;the crystallizing product is nanometer scale supersaturated fee-Al solid solution particles dispersed in amorphous matrix;under 1 GPa pressure amorphous allloy crystallizes in an eutectic way,the crystallizing products are fee-Al,Al_(3)Y,Al_(3)Ni,AlNiY equilibrium crystalline phases etc.High pressure appreciably changes the crystallization mode and the products,elevates the crystallizing temperature. 展开更多
关键词 amorphous alloy CRYSTALLIZATION high pressure effect
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Pyrene Nanocrystals Crystallized by a Continuous Flow Microreactor
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作者 Norihito Doki Masaaki Yokota 《Journal of Materials Science and Chemical Engineering》 2021年第11期1-6,共6页
Pyrene solution and distilled water were flowed through a microreactor at a predetermined flow rate to generate pyrene crystals. Pyrene nanocrystals were crystallized by a Continuous Flow Microreactor. The particle si... Pyrene solution and distilled water were flowed through a microreactor at a predetermined flow rate to generate pyrene crystals. Pyrene nanocrystals were crystallized by a Continuous Flow Microreactor. The particle size and luminescence properties of pyrene nanocrystals produced were evaluated. The crystal mean size between 60 nm and 400 nm could be controlled by the operating conditions. The crystal mean size decreased with increasing flow rate and solution concentration. In addition, the crystal morphology also changed. In the case of slow flow conditions, a needle-like crystal morphology was obtained. The crystal morphology became spherical on increasing the flow rate. Pyrene crystals with size about 400 nm exhibited luminescence at about 470 nm. As the crystal size decreased, the intensity of the luminescence also declined. The luminescence wavelength was in the range of about 370 to 400 nm. 展开更多
关键词 Crystal Size Pyrene Nanocrystals Continuous Process
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Effects of Sm content on crystallized structure and magnetic properties of Co80-xSmxb20 amorphous alloys 被引量:1
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作者 Lei-qiang Lai Yan-hui Li +1 位作者 Feng Bao Wei Zhang 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2020年第4期471-476,共6页
The formation,thermal stability,crystallized structure,and magnetic properties of melt-spun Co80-xSmxB20(x=0–20)amorphous alloys have been investigated.A single amorphous phase is formed for the alloys with x=0–15.T... The formation,thermal stability,crystallized structure,and magnetic properties of melt-spun Co80-xSmxB20(x=0–20)amorphous alloys have been investigated.A single amorphous phase is formed for the alloys with x=0–15.The first crystallization temperature gradually increases from 670 to 955 K as x increases from 0 to 10,and decreases to 836K when x=15.After optimum annealing,the nanocomposite structure consisting of SmCo12B6+fcc-Co+Sm2Co17 phases is formed for the alloys with x=5 and 7.5,and SmCo12B6+Sm2Co17+SmCo3,SmCo12B6+Sm2Co17+SmCo4B,and SmCo12B6+SmCo4B phases are formed for the alloys with x=10,12.5,and 15,respectively.The coercivity of the annealed alloys increases remarkably from 103.5 to 1249.4 kA m^-1 as x increases from 5 to 15,while the magnetization at the applied field of 2.0T decreases from 0.51 to 0.16T.The improved magnetic hardness with rising Sm content is attributed to the formation of the hard magnetic phases with higher magnetocrystalline anisotropy and the increase in their volume fraction. 展开更多
关键词 Co-Sm-B alloy MELT-SPUN Amorphous alloy crystallized structure Magnetic property
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Influence of introducing Zr,Ti,Nb and Ce elements on externally solidified crystals and mechanical properties of high-pressure die-casting Al–Si alloy
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作者 Junjie Li Wenbo Yu +5 位作者 Zhenyu Sun Weichen Zheng Liangwei Zhang Yanling Xue Wenning Liu Shoumei Xiong 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS 2025年第1期147-153,共7页
High pressure die casting(HPDC)AlSi10Mn Mg alloy castings are widely used in the automobile industry.Mg can optimize the mechanical properties of castings through heat treatment,while the release of thermal stress aro... High pressure die casting(HPDC)AlSi10Mn Mg alloy castings are widely used in the automobile industry.Mg can optimize the mechanical properties of castings through heat treatment,while the release of thermal stress arouses the deformation of large integrated die-castings.Herein,the development of non-heat treatment Al alloys is becoming the hot topic.In addition,HPDC contains externally solidified crystals(ESCs),which are detrimental to the mechanical properties of castings.To achieve high strength and toughness of non-heat treatment die-casting Al-Si alloy,we used AlSi9Mn alloy as matrix with the introduction of Zr,Ti,Nb,and Ce.Their influences on ESCs and mechanical properties were systematically investigated through three-dimensional reconstruction and thermodynamic simulation.Our results reveal that the addition of Ti increased ESCs'size and porosity,while the introduction of Nb refined ESCs and decreased porosity.Meanwhile,large-sized Al_3(Zr,Ti)phases formed and degraded the mechanical properties.Subsequent introduction of Ce resulted in the poisoning effect and reduced mechanical properties. 展开更多
关键词 aluminium alloy high-pressure die-casting externally solidified crystals non-heat treatment
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Chinese Wisdom Crystallized
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《Beijing Review》 2020年第24期2-2,共1页
The Civil Code,approved by the National People’s Congress,the national legislature,in late May and to come into effect on January 1,2021,is significant because first and foremost,it will help uphold and improve the s... The Civil Code,approved by the National People’s Congress,the national legislature,in late May and to come into effect on January 1,2021,is significant because first and foremost,it will help uphold and improve the socialist system with Chinese characteristics.It’s going to implement the new concepts,thoughts and strategies of law-based governance outlined by the top leadership,thereby advancing the modernization of the n3tional govemance system and capacity. 展开更多
关键词 CHINESE Wisdom crystallized
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《CRYSTALLIZEDTM-施华洛世奇元素》婚礼概念展览及晚会派对
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《风采》 2009年第1期184-184,共1页
《CRYSTALLIZED<sup>TM</sup>-施华洛世奇元素》上海婚礼汇展于2008年11月18日下午假上海Bubble内隆重举行。此次在上海举办的《CRYSTALLIZED<sup>TM</sup>-施华洛世奇元素》婚礼汇展活动主题是婚礼,并以独特... 《CRYSTALLIZED<sup>TM</sup>-施华洛世奇元素》上海婚礼汇展于2008年11月18日下午假上海Bubble内隆重举行。此次在上海举办的《CRYSTALLIZED<sup>TM</sup>-施华洛世奇元素》婚礼汇展活动主题是婚礼,并以独特时尚手法歌颂婚姻的美丽。会场展出一系列由国际顶尖设计师采用《CRYSTALLIZED<sup>TM</sup>-施华洛世奇元素》 展开更多
关键词 施华洛 crystallized TM 国际顶尖 BUBBLE 李嘉欣 范冰冰 仁海 小提琴演奏
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CRYSTALLIZED^(TM)—施华洛世奇元素
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《国际服装动态》 2007年第9期82-83,共2页
精雕细琢、光彩耀眼的施华洛世奇水晶元素,时刻散发令人难以抗拒的诱人魅力,除深受设计领域的每位设计师、创作人及创意大师欢迎外,也让世界各地眼光独到的客户爱不释手。施华洛世奇为这些举世知名的水晶元素,特别创立了一个独一无二的... 精雕细琢、光彩耀眼的施华洛世奇水晶元素,时刻散发令人难以抗拒的诱人魅力,除深受设计领域的每位设计师、创作人及创意大师欢迎外,也让世界各地眼光独到的客户爱不释手。施华洛世奇为这些举世知名的水晶元素,特别创立了一个独一无二的全新品牌:CRYSTALLIZED<sup>TM</sup> 展开更多
关键词 施华洛 crystallized TM 眼光独到 诱人魅力 令人 品牌展 晶元 切创 资元
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Tunable Curie temperature and magnetocaloric effect of FeCrMoCBYNi bulk metallic glass with different crystallized phases 被引量:6
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作者 Yuanbin Lv Qingjun Chen Youlin Huang 《Journal of Rare Earths》 SCIE EI CAS CSCD 2019年第4期404-409,共6页
The investigation on Curie temperature and magnetocaloric effect of the FeCrMoCBYNi bulk metallic glass(BMG) with different crystallized phases was carried out by XRD,TEM and PPMS. The experimental results show that t... The investigation on Curie temperature and magnetocaloric effect of the FeCrMoCBYNi bulk metallic glass(BMG) with different crystallized phases was carried out by XRD,TEM and PPMS. The experimental results show that the Curie temperature(T_c) of Fe_(45)Cr_(15)Mo_(14)C_(15)B_6 Y_2 Ni_3 BMG with different annealing condition reaches a highest value of 95 K. The value of magnetic entropy change △S_M(T) of Sample 3 reaches a maxima of 0.48 J/(kg·K) at Tc temperature, which result from the interaction among the precipitated phases of(Fe,Cr)_(23)(C,B)_6, Fe_3 Mo_3 C and residual amorphous phase. Based on the experiment results, it can be obtained that the Curie temperature, magnetocaloric effect can reach their optimal value at low temperature, when the content of amorphous phase and precipitated phases type run up to certain value. The magnetic properties of Sample 1 with full amorphous phase and Sample 4 with full crystalline phase will both decrease. 展开更多
关键词 Bulk metallic glass Crystallization CURIE temperature MAGNETOCALORIC effect RARE earths
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Selected area laser-crystallized polycrystalline silicon thin films by a pulsed Nd:YAG laser with 355 nm wavelength 被引量:2
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作者 段春艳 刘超 +3 位作者 艾斌 赖键钧 邓幼俊 沈辉 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2011年第12期48-52,共5页
Selected area laser-crystallized polycrystalline silicon (p-Si) thin films were prepared by the third harmonics (355 nm wavelength) generated by a solid-state pulsed Nd:YAG laser. Surface morphologies of 400 nm t... Selected area laser-crystallized polycrystalline silicon (p-Si) thin films were prepared by the third harmonics (355 nm wavelength) generated by a solid-state pulsed Nd:YAG laser. Surface morphologies of 400 nm thick films after laser irradiation were analyzed. Raman spectra show that film crystallinity is improved with in- crease of laser energy. The optimum laser energy density is sensitive to the film thickness. The laser energy density for efficiently crystallizing amorphous silicon films is between 440-634 mJ/cm^2 for 300 nm thick films and between 777-993 mJ/cm^2 for 400 nm thick films. The optimized laser energy density is 634, 975 and 1571 mJ/cm^2 for 300, 400 and 500 nm thick films, respectively. 展开更多
关键词 polycrystalline silicon thin films Nd:YAG laser laser crystallization
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Lamellar thickness transition of melt-crystallized polybuten-1 tetragonal phase: configurational change in chain folding directions 被引量:1
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作者 Motoi YAMASHITA 《Frontiers of Chemical Science and Engineering》 SCIE EI CSCD 2009年第1期26-32,共7页
Lamellar crystal thickness lc of isotactic polybutene-1(it-PB1)have been investigated for crystal-lization in the melt over a wide range of crystallization temperature T from 40°C to 90°C by small angle X-ra... Lamellar crystal thickness lc of isotactic polybutene-1(it-PB1)have been investigated for crystal-lization in the melt over a wide range of crystallization temperature T from 40°C to 90°C by small angle X-ray scattering experiments and density measurements.The crystal thickness lc demonstrates two linear dependences on inverse supercooling and a transition from one dependence to the other has been observed around T=65°C.Each of the two dependences obeys the nucleation theory in the high and low supercooling ranges,respec-tively.Chain folding free energy q determined from the low supercooling range is larger than that determined from the high supercooling range.Possible mechanisms for the transition are discussed taking account of entropy of chain folding directions. 展开更多
关键词 isotactic polybutene-1 tetragonal phase crystal thickness melt growth chain folding small angle X-ray scattering nucleation theory end surface free energy
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Preliminary study on the possible new modification of isotactic polypropylene crystallized under high pressure
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作者 黄锐 傅强 +1 位作者 彭少贤 张雄伟 《Chinese Science Bulletin》 SCIE EI CAS 1996年第3期257-261,共5页
Isotactic polypropylene (iPP) has complex polymorphic structures. It can crystallize in at least four different modifications, termed α, β, γ and δ, under different crystallization conditions. The modifications of... Isotactic polypropylene (iPP) has complex polymorphic structures. It can crystallize in at least four different modifications, termed α, β, γ and δ, under different crystallization conditions. The modifications of iPP and their transitions have attracted much attention over the years. Studies on the relationships between the modifications and the possibility of formation of new modification are significantly important to investigation on the relationships between structure and properties of iPP. In this note, 展开更多
关键词 ISOTACTIC POLYPROPYLENE MODIFICATION high pressure crystallization.
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Efficient nanostructured heterogeneous catalysts by electrochemical etching of partially crystallized Fe-based metallic glass ribbons
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作者 Qiaoyue Zhang Shun-Xing Liang +3 位作者 Zhe Jia Wenchang Zhang Weimin Wang Lai-Chang Zhang 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2021年第2期159-168,共10页
Although an increasing interest has been attracted to further develop heterostructured catalysts from metallic glasses(MGs) by heat treatment, overcoming surface oxidation effect is still a critical problem for such e... Although an increasing interest has been attracted to further develop heterostructured catalysts from metallic glasses(MGs) by heat treatment, overcoming surface oxidation effect is still a critical problem for such environmental catalysts. Herein, a short-time electrochemical etching of partially crystallized Febased ribbons in 0.3 M H3 PO4 electrolyte enables the formation of honeycomb-like nanoporous structure as effective catalytic active sites in Fenton-like process. Studies of structure and surface morphologies reveal that the formation of nanoporous structure by potentiostatic etching originates from electrochemical potential difference of nanocrystals(a-Fe(Si) and Fe2 B) and residual amorphous phase in partially crystallized ribbons, where Fe2 B having a lower open circuit potential tends to be selectively dissolved.Simultaneously, thin oxide layer after electrochemical etching exposes more active sites for H2 O2 activation and provides an effective protection of nanocrystals from massive loss during etching. Investigation of optimal processing conditions suggests that the selection of electrolyte plays an important role;dye degradation rates of etched ribbons in HNO3 and Na2 SO4 electrolytes can also achieve at least 2 times higher than that of as-annealed ribbons. This work holds the promise to develop novel environmental catalysts by effective electrochemical etching of partially crystallized ribbons. 展开更多
关键词 Metallic glass Nanoporous structure CRYSTALLIZATION Electrochemical etching Selective dissolution
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