期刊文献+
共找到20篇文章
< 1 >
每页显示 20 50 100
Effects of initial δ phase(Ni_3Nb) on hot tensile deformation behaviors and material constants of Ni-based superalloy 被引量:8
1
作者 蔺永诚 何敏 +2 位作者 陈明松 温东旭 陈荐 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第1期107-117,共11页
Effects of initial δ phase(Ni_3Nb) on the hot tensile deformation behaviors and material constants of a Ni-based superalloy were investigated over wide ranges of strain rate and deformation temperature. It is found... Effects of initial δ phase(Ni_3Nb) on the hot tensile deformation behaviors and material constants of a Ni-based superalloy were investigated over wide ranges of strain rate and deformation temperature. It is found that the true stress-true strain curves exhibit peak stress at a small strain, and the peak stress increases with the increase of initial δ phase. After the peak stress, initial δ phase promotes the dynamic softening behaviors, resulting in the decreased flow stress. An improved Arrhenius constitutive model is proposed to consider the synthetical effects of initial δ phase, deformation temperature, strain rate, and strain on hot deformation behaviors. In the improved model, material constants are expressed as the functions of the content of initial δ phase and strain. A good agreement between the predicted and measured results indicates that the improved Arrhenius constitutive model can well describe hot deformation behaviors of the studied Ni-based superalloy. 展开更多
关键词 Ni-based superalloy hot deformation initial δ phase constitutive model material constants
下载PDF
Alloy gene Gibbs energy partition function and equilibrium holographic network phase diagrams of AuCu_3-type sublattice system 被引量:3
2
作者 谢佑卿 李小波 +2 位作者 刘心笔 聂耀庄 彭红建 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第11期3585-3610,共26页
Taking AuCu3-type sublattice system as an example, three discoveries have been presented: First, the third barrier hindering the progress in metal materials science is that researchers have got used to recognizing exp... Taking AuCu3-type sublattice system as an example, three discoveries have been presented: First, the third barrier hindering the progress in metal materials science is that researchers have got used to recognizing experimental phenomena of alloy phase transitions during extremely slow variation in temperature by equilibrium thinking mode and then taking erroneous knowledge of experimental phenomena as selected information for establishing Gibbs energy function and so-called equilibrium phase diagram. Second, the equilibrium holographic network phase diagrams of AuCu3-type sublattice system may be used to describe systematic correlativity of the composition?temperature-dependent alloy gene arranging structures and complete thermodynamic properties, and to be a standard for studying experimental subequilibrium order-disorder transition. Third, the equilibrium transition of each alloy is a homogeneous single-phase rather than a heterogeneous two-phase, and there exists a single-phase boundary curve without two-phase region of the ordered and disordered phases; the composition and temperature of the top point on the phase-boundary curve are far away from the ones of the critical point of the AuCu3 compound. 展开更多
关键词 AuCu3 compound AuCu3-type sublattice system alloy gene Gibbs energy partition function equilibrium holographic network phase diagram systematic metal materials science
下载PDF
Alloy gene Gibbs energy partition function and equilibrium holographic network phase diagrams of Au_3Cu-type sublattice system 被引量:3
3
作者 谢佑卿 聂耀庄 +2 位作者 李小波 彭红建 刘心笔 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第1期211-240,共30页
Taking Au3Cu-type sublattice system as an example, three discoveries have been presented. First, the fourth barrier to hinder the progress of metal materials science is that today’s researchers do not understand that... Taking Au3Cu-type sublattice system as an example, three discoveries have been presented. First, the fourth barrier to hinder the progress of metal materials science is that today’s researchers do not understand that the Gibbs energy function of an alloy phase should be derived from Gibbs energy partition function constructed of alloy gene sequence and their Gibbs energy sequence. Second, the six rules for establishing alloy gene Gibbs energy partition function have been discovered, and it has been specially proved that the probabilities of structure units occupied at the Gibbs energy levels in the degeneracy factor for calculating configuration entropy should be degenerated as ones of component atoms occupied at the lattice points. Third, the main characteristics unexpected by today’s researchers are as follows. There exists a single-phase boundary curve without two-phase region coexisting by the ordered and disordered phases. The composition and temperature of the top point on the phase-boundary curve are far away from those of the critical point of the Au3Cu compound; At 0 K, the composition of the lowest point on the composition-dependent Gibbs energy curve is notably deviated from that of the Au3Cu compounds. The theoretical limit composition range of long range ordered Au3Cu-type alloys is determined by the first jumping order degree. 展开更多
关键词 Au3Cu compound Au3Cu-type sublattice system alloy gene Gibbs energy partition function equilibrium holographic network phase diagrams systematic metal materials science
下载PDF
Holographic alloy positioning design system and holographic network phase diagrams of Au-Cu system 被引量:3
4
作者 谢佑卿 刘心笔 +2 位作者 李小波 彭红建 聂耀庄 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第3期885-906,共22页
Taking Au?Cu system as an example, three discoveries and two methods were presented. First, a new way for boosting sustainable progress of systematic metal materials science (SMMS) and alloy gene engineering (AGE) is ... Taking Au?Cu system as an example, three discoveries and two methods were presented. First, a new way for boosting sustainable progress of systematic metal materials science (SMMS) and alloy gene engineering (AGE) is to establish holographic alloy positioning design (HAPD) system, of which the base consists of measurement and calculation center, SMMS center, AGE center, HAPD information center and HAPD cybernation center; Second, the resonance activating-sychro alternating mechanism of atom movement may be divided into the located and oriented diffuse modes; Third, the equilibrium and subequilibrium holographic network phase diagrams are blueprints and operable platform for researchers to discover, design, manufacture and deploy advanced alloys, which are obtained respectively by the equilibrium lever numerical method and cross point numerical method of isothermal Gibbs energy curves. As clicking each network point, the holographic information of three structure levels for the designed alloy may be readily obtained: the phase constitution and fraction, phase arranging structure and properties of organization; the composition, alloy gene arranging structure and properties of each phase and the electronic structures and properties of alloy genes. It will create a new era for network designing advanced alloys. 展开更多
关键词 Au-Cu system holographic alloy positioning design system equilibrium and subequilibrium holographic network phase diagrams systematic metal materials science network designing advanced alloys
下载PDF
Low temperature solid-phase sintering of sintered metal fibrous media with high specific surface area 被引量:4
5
作者 唐彪 汤勇 +3 位作者 周蕤 陆龙生 刘彬 屈修明 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第8期1755-1760,共6页
A procedure of low temperature solid-phase sintering(LTSS) was carried out to fabricate sintered metal fibrous media(SMFM) with high specific surface area.Stainless steel fibers which were produced by cutting proc... A procedure of low temperature solid-phase sintering(LTSS) was carried out to fabricate sintered metal fibrous media(SMFM) with high specific surface area.Stainless steel fibers which were produced by cutting process were first plated with a coarse copper coating layer by electroless plating process.A low-temperature sintering process was then completed at about 800 °C for 1 h under the protection of hydrogen atmosphere.The results show that a novel SMFM with complex surface morphology and high specific surface area(0.2 m2/g) can be obtained in this way.The effect of sintering temperature on the surface morphology and specific surface area of SMFM was studied by means of scanning electron microscopy and Brunauer-Emmett-Teller.The damage of micro-structure during the sintering process mainly contributed to the loss of specific surface area of SMFM and the optimal sintering temperature was 800 °C. 展开更多
关键词 sintered metal fibrous media low temperature solid-phase sintering electroless copper plating surface morphology specific surface area
下载PDF
就电镜的用途谈其在我局的应用
6
作者 张占海 《同煤科技》 1992年第3期61-63,共3页
关键词 扫描电镜 应用 金相材料 生物医学 地学
下载PDF
非公路矿用车前悬缸活塞杆断裂原因研究
7
作者 韩丽华 班新龙 《建设机械技术与管理》 2011年第11期126-127,共2页
本文针对非公路矿用车前悬活塞杆突发断裂事故,经对其制造工艺和使用情况的分析,确定研究活塞杆突发断裂事故的研究方向,通过活塞杆材料的化学成分分析、力学性能以及金相检测,找出造成活塞杆突发断裂的原因。
关键词 活塞杆 制造工艺 材料金相 显微组织 强度储备
下载PDF
Fabrication of amino-functionalized Fe_3O_4@Cu_3(BTC)_2 for heterogeneous Knoevenagel condensation 被引量:6
8
作者 张艳梅 张静 +2 位作者 田苗苗 储刚 权春善 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2016年第3期420-427,共8页
Metal organic frameworks(MOFs) are an important platform for heterogeneous catalysts.Although MOFs with a smaller particle size exhibit better catalytic performance because of less diffusion limitations,their separa... Metal organic frameworks(MOFs) are an important platform for heterogeneous catalysts.Although MOFs with a smaller particle size exhibit better catalytic performance because of less diffusion limitations,their separation and recycling after catalytic reactions are difficult.The integration of MOFs with magnetic nanoparticles could facilitate their recovery and separation.Especially,the shell thickness of the core-shell structured composites is controllable.In this study,amino-functionalized Fe3O4@Cu3(BTC)2 was fabricated by a stepwise assembly method and its catalytic performance in Knoevenagel condensation was investigated.The results demonstrated that the magnetic hybrid material exhibited a core-shell structure,with a shell thickness of about 2 00 nm.Furthermore,it not only exhibited high catalytic activity,but remarkably,it could also be easily recovered magnetically and recycled without obvious loss of catalytic efficiency after three cycles. 展开更多
关键词 FE3O4 Metal organic frameworks Heterogeneous catalyst Knoevenagel condensation Magnetic separation
下载PDF
Combined powder metallurgy routes to improve thermal and mechanical response of Al−Sn composite phase change materials 被引量:2
9
作者 Chiara CONFALONIERI Maxime PERRIN Elisabetta GARIBOLDI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2020年第12期3226-3239,共14页
Powder metallurgy processes are suitable to produce form-stable solid−liquid phase change materials from miscibility gap alloys.They allow to obtain a composite metallic material with good dispersion of low-melting ac... Powder metallurgy processes are suitable to produce form-stable solid−liquid phase change materials from miscibility gap alloys.They allow to obtain a composite metallic material with good dispersion of low-melting active phase particles in a high-melting passive matrix,preventing leakage of the particles during phase transition and,therefore,increasing the stability of thermal response.Also,the matrix provides structural properties.The aim of this work is to combine conventional powder mixing techniques(simple mixing and ball milling)to improve active phase isolation and mechanical properties of an Al−Sn alloy.As matter of fact,ball milling of Sn powder allows to reduce hardness difference with Al powder;moreover,ball milling of the two powders together results in fine microstructure with improved mechanical properties.In addition,different routes applied showed that thermal response depends on the microstructure and,in particular,on the particle size of the active phase.In more detail,coarse active phase particles provide a fast heat release with small undercooling,while small particles solidify more slowly in a wide range of temperature.On the other hand,melting and,consequently,heat storage are independent of the particle size of the active phase.This potentially allows to“tailor”the thermal response by producing alloys with suitable microstructure. 展开更多
关键词 metallic phase change materials powder metallurgy thermal stability mechanical properties miscibility gap alloys
下载PDF
Phase evolution in AlSi20/8009 aluminum alloy during high temperature heating near melting point and cooling processes 被引量:2
10
作者 Hai-bin LIU Hua-guang SU +2 位作者 Ding-fa FU Fu-lin JIANG Hui ZHANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2020年第5期1157-1168,共12页
The AlSi20/8009 aluminum alloy was heated to high temperatures near the melting point and cooled to investigate the effect of external Si addition on the phase evolution of Al12(Fe,V)3 Si dispersion. Differential scan... The AlSi20/8009 aluminum alloy was heated to high temperatures near the melting point and cooled to investigate the effect of external Si addition on the phase evolution of Al12(Fe,V)3 Si dispersion. Differential scanning calorimeter, scanning electron microscope, energy dispersive spectrometer and X-ray diffractometer were employed.The results showed that Al12(Fe,V)3 Si and Si phases evolved into a needle-like Al4.5 Fe Si phase and a nano-sized V-rich phase during holding the alloy at 580-600℃. With increasing holding temperature to 620-640℃, Al4.5 Fe Si and nano-sized V-rich phases evolved reversibly into Al12(Fe,V)3 Si and Si phases, of which Al12(Fe,V)3 Si occupied a coarse and hexagonal morphology. During the alloy(after holding at 640 ℃) furnace cooling to 570 ℃ or lower, Si and Al12(Fe,V)3 Si phases evolved into strip-like Al4.5 Fe Si and the V-rich phases, which is a novel formation route for Al4.5 Fe Si phase different from Al-Fe-Si ternary system. 展开更多
关键词 SiCp/8009Al composite phase evolution metallurgical joining re-melting COOLING
下载PDF
Growth of Free-Standing AlN Nanocrystals on Nanorod ZnO Template
11
作者 胡卫国 魏鸿源 +3 位作者 焦春美 康亭亭 张日清 刘祥林 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2007年第10期1508-1512,共5页
AlN film is deposited on a nanorod ZnO template by metalorganic chemical vapor deposition. Scanning electron microscopy measurements reveal that this film forms a lying nanorod surface. The grazing incidence X- ray di... AlN film is deposited on a nanorod ZnO template by metalorganic chemical vapor deposition. Scanning electron microscopy measurements reveal that this film forms a lying nanorod surface. The grazing incidence X- ray diffraction further proves that it is entirely a wurtzite AIN structure, and the average size of the crystallite grains is about 12nm,which is near the ZnO nanorod diameter (30nm). This means that the nanorod ZnO template can restrict the AlN lateral overgrowth. Additionally, by etching the ZnO template with H2 at high temperatures,we directly achieve epitaxial lift-off during the growth process. Eventually, free-standing AlN nanocrystals are achieved,and the undamaged area is near 1cm × 1cm. We define the growth mechanism as a "grow-etch- merge" process. 展开更多
关键词 metalorganic vapor phase epitaxy NANOMATERIALS NITRIDE
下载PDF
Effect of Mg-based spherical quasicrystal on microstructures and mechanical properties of ZA54 alloy 被引量:6
12
作者 张金山 张永青 +3 位作者 张焱 许春香 王晓明 严杰 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第7期1199-1204,共6页
To improve the strength, toughness and heat-resistance of magnesium alloy, the microstrucmre and mechanical properties of ZA54 alloy reinforced by icosahedral quasicrystal phase (/-phase) particles were studied. Exc... To improve the strength, toughness and heat-resistance of magnesium alloy, the microstrucmre and mechanical properties of ZA54 alloy reinforced by icosahedral quasicrystal phase (/-phase) particles were studied. Except α-Mg, φ-phase and τ-phase, MgZnYMn I-phase particles can be obtained in ZA54-based composites by the addition of icosahedral quasicrystal-contained Mg-Zn-Y-Mn master alloy. The introduction of MgZnYMn I-phase into ZA54 alloy has great contribution to the refinement of matrix microstructures and the improvement of mechanical properties. When the addition of Mg-based spherical quasicrystal master alloy is up to 3.5% (mass fraction), the macro-hardness of ZA54-based composites is increased to HB 68. The impact toughness of composites reaches the peak value of 18.3 J/cm^2, which is about 29% higher than that of ZA54 mother alloy. The highest tensile properties at ambient and elevated temperatures with master alloy addition of 2.5% (473 K) are also obtained in ZA54-based composites with 3.5% (mass fraction) Mg-Zn-Y-Mn master alloy addition. The ultimate tensile strength of composites at ambient and elevated temperatures are 192.5 MPa and 174 MPa, which are 23.4% and 33.8% higher than that of ZA54 mother alloy, respectively. The improved mechanical properties are mainly attributed to the pinning effect of I-phase on grain boundaries. 展开更多
关键词 magnesium alloy spherical quasicrystal particles ZA54 alloy composite strengthening heat-resistance ~: magnesium alloy spherical quasicrystal particles ZA54 alloy composite strengthening HEAT-RESISTANCE
下载PDF
Influence of Doping on the Mott Metal—Insulator Transition in Infinite Dimensions
13
作者 TONGNing-Hua 《Communications in Theoretical Physics》 SCIE CAS CSCD 2002年第5期615-618,共4页
We have studied the effect of hole-doping on the established scenerio of the first-order Mott metal-insulator transition (MIT) at half-filling using dynamical mean-field theory and exact diagonalization technique. The... We have studied the effect of hole-doping on the established scenerio of the first-order Mott metal-insulator transition (MIT) at half-filling using dynamical mean-field theory and exact diagonalization technique. The Mott insulator state is changed into metallic state immediately as holes are doped into the system. The latter is expected to be Fermi liquid. The previously found unanalytical structure of MIT no longer exists for doping as small as 2 percent. We compare our results with that obtained from Gutzwiller approximation. 展开更多
关键词 Hubbard model metal-insulator transition DOPING Fermi liquid
下载PDF
手持式发动机曲轴断裂问题的分析与解决
14
作者 刘永根 杨慧明 +3 位作者 徐华俊 费吴凯 苑文龙 刘毅 《小型内燃机与车辆技术》 2022年第3期28-31,共4页
针对小型手持式发动机在耐久试验过程中出现曲轴主轴颈断裂问题,从曲轴材料的金相组织以及曲轴的结构型式、热处理工艺、毛坯加工、强化工艺等方面对曲轴主轴颈断裂原因进行了分析,提出了改进方案。通过优化结构布置和热处理工艺,经过... 针对小型手持式发动机在耐久试验过程中出现曲轴主轴颈断裂问题,从曲轴材料的金相组织以及曲轴的结构型式、热处理工艺、毛坯加工、强化工艺等方面对曲轴主轴颈断裂原因进行了分析,提出了改进方案。通过优化结构布置和热处理工艺,经过耐久试验验证,有效解决了曲轴主轴颈断裂问题。 展开更多
关键词 曲轴 主轴颈 断裂 材料金相组织 热处理工艺
下载PDF
固定式双臂混砂机底座螺栓脆断分析
15
作者 穆大伟 王世彬 申汉秦 《新疆农机化》 2001年第2期44-44,39,共2页
经对螺栓脆断分析,结果表明螺栓脆断原因是原材料金相组织存在游离渗碳体及带状组织所致。
关键词 螺栓 脆断 游离渗碳体 带状组织 固定式双臂混砂机 底座 材料金相组织
下载PDF
N-doped carbon-coated Fe_(3)N composite as heterogeneous electro-Fenton catalyst for efficient degradation of organics
16
作者 Juan Xiao Junwei Chen +3 位作者 Zuqiao Ou Junhang Lai Tongwen Yu Yi Wang 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2021年第6期953-962,共10页
Herein,the application of a N-doped graphitic-carbon-coated iron nitride composite dispersed in a N-doped carbon framework(Fe_(3)N@NG/NC)is investigated as a heterogeneous electro-Fenton(HE-EF)catalyst for the efficie... Herein,the application of a N-doped graphitic-carbon-coated iron nitride composite dispersed in a N-doped carbon framework(Fe_(3)N@NG/NC)is investigated as a heterogeneous electro-Fenton(HE-EF)catalyst for the efficient removal of organics.The simultaneous carbonization and ammonia etching of iron-based metal organic framework(Fe-MOF)materials yielded well-dispersed N-doped carbon-coated Fe_(3)N nanoparticles with a diameter of~70 nm.The Fe_(3)N and pyridinic N endowed the composite with high HE-EF activity for decomposing the electrogenerated H_(2)O_(2) to•OH.The Fe_(3)N@NG/NC exhibited outstanding HE-EF performance in removing various organic pollutants with low iron leaching.A removal rate of 97-100%could be obtained for rhodamine B(RhB),dimethyl phthalate,methylene blue,and orange Ⅱ in 120 min at a pH of 5.0.When the solution pH was set to 3.0,5.0,7.0,and 9.0,the removal rate of RhB reached 100%,96%,92%,and 81%,respectively,in 60 min at an optimum voltage of 0.0 V(vs.reversible hydrogen electrode(RHE)).Moreover,the concentration of leached iron was expected to be below 0.03 mg/L in a wide pH range of 3.0-9.0.In addition,the RhB removal efficiency remained as high as 90%after six cycles in the reusability experiments.This work highlights the MOF-derived Fe_(3)N composite as an efficient HE-EF catalyst and the corresponding catalytic mechanism,which facilitates its application in wastewater treatment. 展开更多
关键词 Fe_(3)N@NG/NC composite Heterogeneous electro-Fenton Metal-organic frameworks Degradation Organic pollutants
下载PDF
Thermal Analysis of Metal Foam Matrix Composite Phase Change Material 被引量:1
17
作者 SONG Xiange 《Journal of Thermal Science》 SCIE EI CAS CSCD 2015年第4期386-390,共5页
In this paper,CPCM(Composite Phase Change Material)was manufactured with metal foam matrix used as filling material.The temperature curves were obtained by experiment.The performance of heat transfer was analyzed.The ... In this paper,CPCM(Composite Phase Change Material)was manufactured with metal foam matrix used as filling material.The temperature curves were obtained by experiment.The performance of heat transfer was analyzed.The experimental results show that metal foam matrix can improve temperature uniformity in phase change thermal storage material and enhance heat conduction ability.The thermal performance of CPCM is significantly improved.The efficiency of temperature control can be obviously improved by adding metal foam in phase change material.CPCM is in solid-liquid two-phase region when temperature is close to phase change point of paraffin.An approximate plateau appears.The plateau can be considered as the temperature control zone of CPCM.Heat can be transferred fiom hot source and be uniformly spread in thermal storage material by using metal foam matrix since thermal storage material has the advantage of strong heat storage capacity and disadvantage of poor heat conduction ability.Natural convection promotes the melting of solid-liquid phase change material.Good thermal conductivity of foam metal accelerates heat conduction of solid-liquid phase change material.The interior temperature difference decreases and the whole temperature becomes more uniform.For the same porosity with a metal foam,melting time of solid-liquid phase change material decreases.Heat conduction is enhanced and natural convection is suppressed when pore size of metal foam is smaller.The thermal storage time decreases and heat absorption rate increases when the pore size of metal foam reduces.The research results can be used to guide fabricating the CPCM. 展开更多
关键词 Metal Foam Matrix Composite Phase Change Material Thermal Storage Heat Absorption Rate
原文传递
Low-temperature thermoplastic welding of metallic glass ribbons for in-space manufacturing 被引量:2
18
作者 Chaoqun Liao Ming Liu +9 位作者 Qi Zhang Wen Dong Rui Zhao Bobo Li Zhiwei Jiao Jian Song Wei Yao Shaofan Zhao Haiyang Bai Wei-Hua Wang 《Science China Materials》 SCIE EI CAS CSCD 2021年第4期979-986,共8页
In-space manufacturing is an emerging and promising research field in space industry,which benefits the development of space explorations.Owing to the microgravity,high vacuum and complexity of the space environment,a... In-space manufacturing is an emerging and promising research field in space industry,which benefits the development of space explorations.Owing to the microgravity,high vacuum and complexity of the space environment,a special manufacturing strategy for alloys is highly demanded for the in-space manufacturing.Herein,a lowtemperature thermoplastic metallic welding method was proposed and employed for La-based metallic glass ribbons.With the sandwiched structures of La-and Zr-based ribbons,the welded samples exhibit a competitive fracture strength and an increased tensile strain than those of the welded la-based samples due to the second phase strengthening.This suggests that metallic glass is an ideal material candidate for in-space manufacturing,and can be well manufactured at a nonmelting state with good mechanical performances.In addition,the thermoplastic manufacturing method can also feature a moderate processing time window.In general,this work presents the promising potential of low-temperature thermoplastic welding strategy for in-space manufacturing of metallic materials. 展开更多
关键词 in-space manufacturing metallic glasses thermoplastic welding mechanical properties
原文传递
Fabrication of Noble metal-semiconductor hybrid nanostructures using phase transfer 被引量:3
19
作者 Tanushree Bala Ajay Singh +4 位作者 Ambarish Sanyal Catriona O'Sullivan Fathima Laffir Claudia Coughlan Kevin M. Ryan 《Nano Research》 SCIE EI CAS CSCD 2013年第2期121-130,共10页
An easy and effective solution based procedure for the synthesis of noble metal (both Au and Ag) tipped semiconductor nanomaterials is demonstrated where the metal precursors are taken in water and the semiconductor... An easy and effective solution based procedure for the synthesis of noble metal (both Au and Ag) tipped semiconductor nanomaterials is demonstrated where the metal precursors are taken in water and the semiconductors in organic medium, exploiting the phase transfer and reducing capability of suitably chosen ligands. The phase tranfer route is a generalised approach to form either Ag or Au tips on cadmium chalcogenide nanoparticles and nanorods. While multiple dots of noble metals are formed on the semiconductor nanomaterials initiall~ these coalesce into larger islands with time. The hybrids are characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), photoluminescence (PL), ultraviolet-visible spectroscopy (UV-vis) and X-ray photoelectron spectroscopy (XPS). A detailed FTIR analysis was also carried out to delineate the role of the ligands in the synthesis. 展开更多
关键词 semiconductor-metalhybrids Ag tips Au tips phase transfer
原文传递
A macroscopic constitutive model of shape memory alloy considering cyclic effects 被引量:1
20
作者 ZHOU Bo YOON Sung-Ho 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2013年第4期755-764,共10页
This paper presents a macroscopic constitutive model reproducing the hysteretic behaviors of the superelastic shape memory alloy (SMA) under cyclic loading. The progressive increase of residual strain with the increas... This paper presents a macroscopic constitutive model reproducing the hysteretic behaviors of the superelastic shape memory alloy (SMA) under cyclic loading. The progressive increase of residual strain with the increased cycle number in such materials is assumed to be a consequence of the progressive increase of residual stress-induced martensitic volume fraction upon the cyclic effects. The progressive decrease of phase transformation critical stresses with the increased cycle number in such materials is assumed to be a result from the progressive increase of phase transformation critical temperatures upon the cyclic effects. A cyclic evolution equation is supposed to describe the influences of cycle effects on the material properties of the SMA under cyclic loading. A phase transformation equation expressing the phase transformation behaviors of the SMA under cyclic loading is established based on the differential relationship between martensitic volume fraction and the free energy increment of phase transformation. A mechanical constitutive equation predicting the mechanical characteristics of the SMA under cyclic loading is developed on the basis of thermodynamics and continuum mechanics. The cyclic evolution equation, phase transformation equation, and mechanical constitutive equation together compose the presented macroscopic constitutive model considering cyclic effects. Results of the numerical simulations illustrate that it can well reproduce the superelastic hysteretic behaviors of the SMA under cyclic loading. 展开更多
关键词 shape memory alloy cyclic effect cyclic evolution equation phase transformation equation mechanical constitutive equation
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部