研究金属材料高温动态拉伸性能新方法

采用自行设计带有小型加温装置的改进的分离式Hopkinson拉杆装置测试了金属材料在高温条件下的动态拉伸性能,并用修正的Johnson-Cook模型作为材料的本构关系,提出了一种拟合金属材料在弹性及塑性阶段应变率及温度相关的损伤模型,并拟合出参数.结果表明:改进装置能够精确控制加温速率及温度,减小杆端软化的影响,测试结果相对误差小于1.5%;金属材料304不锈钢的屈服应力及断裂应变具有明显的正应变率效应的温度软化效应,但材料弹性模量具有负应变率效应和负温度效应;在293—625K之间计算结果和试验结果吻合较好,表明可用这种方法测试及估算材料高温动态力学性能,并用于工程分析.     

Zr基非晶合金准静态压缩下的多重剪切带行为

利用IUTM和SEM研究了Zr-Ti-Ni-Cu块状非晶合金的准静态单轴压缩变形和断裂行为. 研究表明:该合金的室温压缩变形过程主要表现为弹性和塑性变形,塑性变形阶段没有加工硬化现象. 在准静态压缩条件下Zr基非晶合金表现出多重剪切效应,提高了塑性. 微观研究证明,剪切带的滑移分枝与相互交叉是非晶合金塑性提高的主要机制. 沿着剪切带发现了微空洞和微裂纹,剪切带的形成与自由体积的合并有关. 塑性变形过程中形成脉纹状断口形貌,受力状态的不同脉状花纹表现为不同的形式.     

Rapid Screening for Insecticidal Compounds Using [3H] EBOB Binding Assay

Binding assay is a convenient, simple, inexpensive, and rapid method that can be used for rapid screening insecticidal compounds. The present study examines 6 compounds for their inhibition of [^3H] EBOB bound to housefly-head membranes, of which 3 compounds have potency for housefly-head membranes.     

金属材料表面二次冶金对电击穿的影响

研究了合金真空击穿后,表面二次冶金过程及表面熔化层的显微组织对真空电击穿的影响．介绍了真空击穿的实验过程,测定了ＣｕＣｒ５０、真空Ｃｕ、４０Ｃｒ及ＣｒＣｕ５０中添加ＷＣ等合金的耐电压强度Ｅｂ,并对ＣｕＣｒ５０合金一次击穿和经１００次击穿后的表面组织进行了观察．研究结果表明：材料的首击穿具有选择性,电击穿老炼是电弧作用下表面发生二次冶金的过程,在ＣｕＣｒ合金中添加ＷＣ提高了Ｃｒ相的耐电压强度．     

抄针周期对纯涤纺梳棉棉结的影响研究

通过在金属针布梳棉机上专门的抄针实验,研究抄针前后不同时刻的棉结粒数的变化规律。结果表明：金属针布在纯涤纺时仍需要抄针,合理的抄针周期应为每两天一次。     

Computational diffusion kinetics and its applications in study and design of rare metallic materials

Computational diffusion kinetics(CDK),with a spirit of and being coupled with the computational thermodynamics(CT,or called as the CALPHAD technique),plays increasingly important role in the alloy design/optimization and microstructure control during the processing of advanced metallic materials.This paper is to highlight recent progress of CDK in research with great focus on novel Ti and Zr alloys,which was largely performed in the authors’group.It ends with one representative example of the applications of CDK,coupled with CT,quantitative phase field,and three-dimensional(3D)statistical calculation,in designing the heattreatment schedule for the dual phase(αβ)Ti–6Al–4V alloys.     

Thermal stability and magnetic properties of Fe–Co–M–Zr–Nb–Ge–B(M=Mo,Cr) bulk metallic glasses

Fe62Co8 xMxZr6Nb4Ge1B19(M=Mo, Cr) bulk metallic glasses were synthesized in the diameter range up to 2 mm by copper mold casting,which exhibit high thermal stability and large glass-forming ability. The super-cooled liquid region diminishes by the dissolution of Mo. The addition of 2 at% Cr leads to the broading of the liquid region remarkably, resulting in the improvement of thermal stability. The crystallization takes place through a single exothermic reaction, accompanying the precipitation of more than three kinds of crystallized phases such as α-Fe,Fe2Zr and ZrB2. The Fe-based alloys show soft ferromagnetic properties. The saturation magnetization(ss) decreases with increasing Mo or Cr content while the saturated magnetostriction increases with raising Mo or Cr content. There is no evident change in the ssand coercive force(Hc)with annealing temperature below the crystallization temperature, which suggests a more relaxed atomic configuration the glasses have. The crystallization causes a substantial enhancement in both ssand Hc. Each soft magnetic property of the glasses containing Cr with higher thermal stability is superior to that of the alloys containing Mo.     

挤压铸造制备三维连续网络结构增强金属基复合材料

基于真空反压浸渍多孔陶瓷获得一种新型三维连续网络结构增强的金属基复合材料的基础上,采用挤压铸造的方法对这种新型结构金属基复合材料的制备方法作进一步研究．以Ａｌ－ＴｉＯ２－Ｃ系为例,对利用自蔓延高温合成方法（ＳＨＳ）制备的Ａｌ２Ｏ３－ＴｉＣ多孔连通网络陶瓷骨架进行挤压铸造Ｌｙ１２Ａｌ合金液获得这种复合材料,并利用扫描电镜、光学显微镜和透射电镜对Ａｌ２Ｏ３－ＴｉＣ多孔陶瓷材料,以及得到的三维连续网络结构增强金属基复合材料的微观形貌特征进行了观察和分析     

丁二烯在聚苯乙烯和丁苯多嵌段共聚物膜中扩散系数的测定与计算

用石英弹簧法测定了298．15K和308．15K下丁二烯在聚苯乙烯和丁苯多嵌段共聚物膜中的吸收曲线,结果表明丁二烯在聚苯乙烯膜和丁苯多嵌段共聚物膜中的吸收曲线近似呈费克型,扩散吸收曲线的形态与相对分子质量及其分布无关。用黄永民等的吸附一吸收双模式模型对实验结果进行了关联,获得无限稀释扩散系数和平衡溶解度。     

HL60细胞质膜上存在水通道蛋白

采用细胞影像系统,测定了ＨＬ６０细胞转运水分活力。结果表明,ＨＬ６０细胞在低渗介质中体积迅速增大,且随着渗透梯差的加大而显增大;在渗透液液的质量摩尔浓度梯差为１００,１５０,２００ｍｍｏｌ·ｋｇ＾－１下,Ｐｆ值分别为０．１４×１０＾－３,０．４０×１０＾－３,０．４３×１０＾－３ｃｍ·ｓ＾－１;并且发现ＨＬ６０细胞转运水分活力可以被ＨｇＣｌ２抑制,由此可见,ＨＬ６０细胞转运水分活力表现出典型的水