磁流体微观结构的模拟与控制方法研究

考虑磁流体中粒子受力及运动特性, 运用分子动力学模拟方法研究了磁流体的三维微观结构, 计算模拟了磁流体在有、无外加磁场作用下的微观结构, 分析了粒子体积份额、磁偶极子作用势以及外加磁场作用势对磁流体微观结构的影响. 结果表明在无外加磁场作用时, 磁流体中的磁性粒子呈现无序状态, 粒子会聚集成团; 在外加磁场条件下, 磁流体中的磁性粒子沿磁场方向取向形成链状结构, 且随着粒子体积份额的增加、磁偶极子作用势以及外加磁场作用势的增大, 链状结构更为明显.     

基于微观分析的质量侵蚀模型研究

采用微观分析实验研究侵彻实验后剩余弹体表面的质量侵蚀痕迹,确定和总结弹体质量侵蚀的物理机制.基于微观分析实验结果,改进Archard模型的形式,获得表征切削弹体头部材料的切削速度,考虑侵彻过程中弹靶间的摩擦生热对切削因子的影响,采用温度项连接摩擦与切削两种机制,采用节点回退法表征弹体头部形状的变化,建立融合摩擦与切削两种机制的质量侵蚀模型,对比数值计算结果与国内外典型的实验数据,证实该弹体质量侵蚀模型有效.     

水泥早期水化产物的TEM研究

通过透射电子显微术（TEM）研究了水泥早期水化产物Ca（OH）2、水化硅酸钙凝胶（CSH）、钙矾石（AFt）、单硫水化硫铝酸钙（AFm）微观形貌、结晶形态、元素构成.并结合SEM与XRD研究结果,讨论了TEM在研究水泥早期水化产物方面优势.研究结果表明,使用TEM研究水泥早期水化产物,其观察结果比SEM更加精确和可靠.水化初期生成CSH凝胶为具有大量皱褶非晶态箔状产物,其Ca/Si比为1.3±0.2;水化初期生成AFt和AFm,发现了两者微观貌差别,确认了两者均为由尺寸小于20nm纳米晶粒无序组成多晶层状结构.本文讨论了SEM和TEM方法分别所CSH凝胶Ca/Si比差异原因.     

干化-湿化路径下红黏土微观结构演化规律研究

以桂林红黏土为研究对象,借助扫描电子显微镜法(SEM)和压汞法(MIP)对不同初始孔隙比的压实土样和泥浆土样在干化-湿化路径下微观结构演化规律开展研究.扫描电子显微镜结果表明,饱和压实土样的微观结构主要由集聚体、集聚体间大孔隙和集聚体内小孔隙(颗粒间孔隙)组成;饱和泥浆土样的微观结构主要由片层状的黏土颗粒和较为均匀的颗...     

微观相场法研究镍基合金扩散通道取向效应与相间作用机制

基于微观相场动力学模型,以Ni75Al6.0V19.0合金为对象,研究了其相变过程的扩散通道取向效应及其通道形成过程中相间作用机理．研究表明：在弹性错配应力场作用下,V原子会沿着[1001方向形成扩散通道,形成沿其短轴方向生长的D022相,从而促使Al原子在相邻处也沿着相同的方向形成扩散通道,产生L12相的定向生长;应力的升高,取向效应先增强再减弱;在较大应力下,V原子的平均占位较晚达到稳定、Al原子则较早．     

铜离子对绿色微囊藻增殖的影响

通过藻类增长潜力（AGP）实验,研究了不同浓度铜离子对绿色微囊藻（Microcystis viridis）增殖的影响。结果显示,低浓度的Cu^2＋（0．001～0．1mg／L）对绿色微囊藻的增殖有促进作用,高浓度的Cu^2＋（〉1mg／L）降低了藻细胞密度、叶绿素a以及微囊藻毒素的含量,抑制了绿色微裳藻的增殖。     

Effect of one-step aging on microstructure and properties of a novel Al-Zn-Mg-Cu-Zr alloy

The effect of one-step aging temper on the mechanical properties,electrical conductivity and the microstructure of a novel Al-7.5Zn-1.6Mg-1.4Cu-0.12Zr alloy has been investigated.The results indicated that with elevating the aging temperature from 100°C to 160°C,the aging response rate was greatly accelerated,and the UTS at peak aging condition decreased,while the corresponding TYS increased.However,the electrical conductivity of the alloy became higher.After aging for 24 h at 120°C,the peak UTS and TYS values were achieved as 591 MPa and 541 MPa,respectively;but the alloy achieved a lower conductivity,20.4 MS/m.When T6 temper was performed at 140°C for 14 h,the UTS decreased only by 1%of the former,whereas the TYS and the electrical conductivity increased obviously,which were up to 559 MPa and 22.6 MS/m,respectively.The major strengthening precipitates of the peak-aged alloy were GP zones andη′phase.The precipitates in both the matrix and the grain boundary became coarser with rising aging temperature.There were obvious PFZs along the grain boundary both in T6 conditions aged at 140°C and 160°C.     

解聚复肾宁对糖尿病大鼠肾脏HGF表达的影响

目的观察解聚复肾宁（JJFSN）对糖尿病大鼠肾HGF表达的影响及肾保护作用。方法SD大鼠腹腔注射链尿佐菌素法建立糖尿病模型,随机分为正常对照组、模型组、解聚复肾宁治疗组、依那普利治疗组、JJFSN＋依那普利治疗组。12周后,检测各组空腹血糖（FBG）、尿素（BU）、24h尿β2微球蛋白（β2-MG）、肌酐清除率（Ccr）;免疫组化法检测肾组织HGF表达,放射免疫法测定大鼠血清胰岛素（Ins）含量,透射电镜观察肾脏超微结构。结果与模型组比较,各治疗组大鼠FBG、BU、β2-MG明显降低,Ccr明显升高,血清Ins含量增加,肾组织HGF表达明显上调,肾组织病理变化减轻,其中以J＋Y组改善最显著（P〈0．05）。结论JJFSN对DM大鼠肾脏形态争功能有明显保护作用,其机制可能与其上调肾脏HGF表达、保护胰岛β细胞、延缓肾脏纤维化进程有关。     

Effect of Cu seed on the synthesis and characterization of FeCo alloy nano-particles by using polyol method

Fine metal particles with uniform shape,narrow size distribution and high purity are increasingly needed for specific uses in high tech industrial application.We report the direct chemical synthesis of FeCo alloy particles using the mixture of FeCl2·4H2O,Co(Ac) 2·4H2O(Ac:acetate) and NaOH in ethylene glycol,and then obtained FeCo alloy particles better dispersed by adding the polyvinylpyrrolidone(PVP) and also the size could be controlled by adding copper.The prepared nano-particles were characterized using FESEM,XRD and VSM.The mean diameter of these particles was varied in the range of submicrometer to nanometer with metal-ion concentration.FeCo particles showed the typical soft magnetic properties.