油溶性铜纳米微粒作为液体石蜡添加剂的摩擦学性能研究

采用液相化学还原法在溶液中原位合成了有机化合物表面修饰铜纳米微粒,用航向电子显微镜表征了微粒的尺寸、形貌和结构,在四球摩擦磨损试验机上考察了其作为液体石蜡添加剂的摩擦学性能,并与二烷基二硫代磷酸锌（ＺＤＤＰ）进行了对比,结果表明：铜纳米微粒添加剂能够显著提高基础油的极压性能,同时具有良好的抗磨性能,尤其是在高负荷下其性能优于ＺＤＤＰ,采用ＥＰＭＡ和ＸＰＳ对铜纳米微粒的极压抗磨机理进行了分析,发现在     

THE CRYSTAL STRUCTURE OF SILVER CARP INSULIN AT MEDIUM RESOLUTION

It is an important way of surveying the structure-functionrelationship of insulin tostudy insulins from different species. Based on the structure model of an orthorhombic crys-tal obtained by the molecular replacement method, the crystallographic refinement of a hex-amer of silver carp insulin in an asymmetric unit has been carried out with 2.8A resolutiondata using the restrained least- squares method. The comparisons of insulin structures haveshown that the six silver carp insulin molecules have very similar but not identical three- di-mensional structures which are similar to the known 2Zn pig insulin structure but remarka-bly different in some local conformations.     

油酸／PS／TiO2复合纳米微球对液体石蜡抗磨性能的影响研究

采用种子乳液聚合法制备了油酸／PS／TiO2复合纳米微球,在四球摩擦磨损试验机上考察了油酸／PS/TiO2复合纳米微球添加剂对液体石蜡抗磨性能的影响,采用X射线光电子能谱分析了钢球磨斑表面边界膜元素的组成及化学状态。结果表明,油酸／PS／TiO2复合微球作为润滑油添加剂具有良好的抗磨性能,能显著提高基础油的失效载荷。表明分析结果表明,复合纳米微球的抗磨作用取决于其摩擦化学反应所生成的含有TiO2及部分添加剂分解产物的复合膜。     

非局部奇摄动半线性椭圆型方程(英文)

本文讨论了半线性椭圆型方程非局部奇摄动问题 .在适当条件下 ,利用不动点原理 ,对边值问题解的存在性和渐近性态作了研究 .     

Spin excitations in a K0.84Fe1.99Se2 superconductor as studied by MSssbauer spectroscopy

Mossbauer spectroscopy was used to probe the site-specific information of a K0.84Fe1.99Se2 superconductor. A spin excitation gap, △E≈5.5 meV, is observed by analyzing the temperature dependence of the hyperfine magnetic field （HMF） at the iron site within the spin wave theory. Using the simple model suggested in the literature, the temperature dependence of the HMF is well reproduced, suggesting that, below room temperature, the alkali metal intercalated iron selenide superconductors can be regarded as ferromagnetically coupled spin blocks that interact with each other antiferromagnetically to form the observed checkerboard-like magnetic structure.     

A DISCRETE NONLINEAR STEPPING OPTIMIZATION METHOD AND ITS APPLICATION

Most of the practical design variables should always be discrete quantity within engineering optimization design problems. To obtain the true optimization solution, a discrete optimization method must be used. In this paper, a new method called step optimization search method is presented to solve the discrete quantity mathematic programming problems. The basic idea oft his method is to find out an initialfeasible point and then to search the optimum point step by step in the neighbouring region of this point so as to obtain an improved new discrete point. Respectively, the new point can be taken us initial one, and the whole process can be carried out once more until the optimum solution of the problem is obtained. Some results of numerical examples of practical problems show that this new method can solve problems quickly and simply and can be applied in a lot of engineering design problems.     

Bi-Pb-Sn-Cd四元合金纳米微粒的制备及其摩擦磨损性能研究

通过直接对Bi-Pb-Sn-Cd四元块状合金进行超声分散制备了相应的四元合金纳米微粒;采用X射线衍射仪和热分析仪分析所制备的纳米微粒结构;采用透射电子显微镜考察了纳米颗粒的形貌及尺寸分布;采用四球摩擦磨损试验机考察了纳米颗粒的摩擦学性能.结果表明,所制备的纳米颗粒为低熔点共晶合金纳米微粒,颗粒平均尺寸在10～20 nm之间,其作为润滑油添加剂表现出良好的摩擦学性能.     

CO_2反演中大气散射影响的光程校正方法

CO2作为影响气候变化最重要的温室气体,其反演精度达到1%是气候研究的基本要求。在反演中解决大气散射的影响,是提高CO2反演精度的关键问题之一。温室气体观测卫星为了实现高光谱分辨率,其光谱带宽通常较窄。高光谱分辨率对CO2浓度变化敏感,而窄带宽在采用传统差分吸收光谱(DOAS)法以快慢变分离的方式处理散射时难以保证反演精度。针对我国高光谱卫星CO2反演算法的开发需求,从光程的角度研究了散射对CO2反演的影响,并与传统DOAS方法在沙漠和草地两种区域进行了对比。结果显示相对于传统DOAS方法,该方法在沙漠和草地区域的应用均使CO2的反演精度得到提高,达到或接近1%的精度需求,反演结果的相关性和数据离散度也得到改善,这表明该方法能有效降低大气散射对CO2反演的影响。     

硫磺素型聚乳酸/苯磺酸室温磷光体系的构建

在硫磺素上分别引入给电子基氧、 硫和甲氧基, 合成出2-[4-(苯并噻唑-2-基)苯氧基]乙-1-醇(BT-OH)、 2-{[4-(苯并噻唑-2-基)苯基]硫代}乙-1-醇(BT-SH)和2-[4-(苯并噻唑-2-基)-2-甲氧基苯氧基]乙-1-醇(BT-M-OH) 3种硫磺素衍生物. 利用硫磺素衍生物作为引发剂引发D,L-丙交酯聚合, 得到3种硫磺素型聚乳酸, 再加入苯磺酸, 构建出可在室温下产生磷光的硫磺素型聚乳酸/苯磺酸体系, 实现了从荧光到磷光的可调分子发射, 其中磷光寿命最长达108.19 ms. 研究发现, 引入苯磺酸会使硫磺素型聚乳酸产生分子内电荷转移态, 质子化效应导致绿色和橘色的磷光发射.