Cu原子簇触发形核下的深过冷Ag-Ge合金组织演变研究

采用玻璃包覆的方法获得具有较大过冷度的亚共晶、共晶以及过共晶Ag-Ge合金熔体,并通过高能离子束轰击Cu箔产生Cu原子团簇溅射到过冷合金熔体中来触发非均质形核过程.凝固后合金显微组织的分析结果表明:在深过冷合金熔体中引入Cu原子团簇,它对亚共晶、共晶以及过共晶Ag-Ge合金的显微组织演变有着不同的影响效果,分析了显微组织的演变规律与形成机制. The Ag-Ge alloy melts with deeply undercooled hypoeutectic, eutectic and hypereutectic were obtained via glass fluxing technique. The nucleation of the deeply undercooled alloy melts were triggered by atoms cluster sputtering on the surface of the melts. The atoms clusters were generated by an ion beam bombarding on the Cu foil fixed above the alloy melts. The resultant microstructure reveals that the induced atom clusters exert great influence on the microstructural evolution of the highly undercooled eutectic and hypereutectic Ag-Ge alloys, but no obvious influence on the highly undercooled hypoeutectic alloy. The microstructural evolution and formation mechanism were analyzed and discussed.

湍流计算的多尺度模型与尺度间相互作用规律

湍流计算的多尺度模型把物理（空间）尺度分为大小尺度，大小尺度（LSS）运动微分积分方程组通过湍流应力项相耦合。利用该方程组计算了不可压槽道和平面混合层流动的三维时间演化，同时算出平均流速、最大和平均脉动速度。平均速度和平均脉动速度与NS计算结果一致，NS计算未能算出最大脉动速度。混合层最大脉动速度突增现象与流动转捩猝发现象相对应。LSS方程计算中，小尺度l_(2f)与大小涡分割尺度l_c之比约为1/2～1/4时，数值解很好收敛；l_(2f)/l_c = 1/5未能获得收敛解。解析分析证实：涡尺度介于l_c/3和l_c之间的小涡（称作近程小涡）及介于l_c/2和l_c之间的小涡（定义为共振小涡）分别提供了所有的小涡对大涡作用应力的90%和75%，给出近程小涡和共振小涡作用应力的微分表达式；获得微分形式的大小尺度封闭方程组及大尺度运动封闭方程组。对单向剪切湍流，共振作用应力公式简化为Prandtl混合长理论应力公式。给出初步数值计算结果及湍流多尺度模型基本方程组的一般形式。

A thermal-elastic analysis on laser-induced reverse bulging and plugging in circular brass foil

A new failure mode is observed in circular brass foils induced by laser beam. The new failure is based on the following experimental facts : (1) the peripheries of the circular brass foils are fixed and the surfaces of the foils are radiated by laser beam ; (2) the laser beam used is considered to be non-Gaussian spatially, actually an approximately uniform distribution limited in a certain size spot ; (3) the pulse on time of laser beam should be 250 μs, i.e. so called long duration pulse laser. The failure process consists of three stages ; i.e. thermal bulging, localized shear deformation and perforation by plugging. The word reverse in reverse bulging and plugging mode means that bulging and plugging occur in the direction of incident laser beam. To study the newly-discovered type of failure quantitatively, analytical solutions for the axisymmetric temperature field and deflection curve are derived. The calculated results show that the newly discovered failure mode is attributed to the spatial structure effect of laser beam indeed.

Stability of ZrTiCuNiBe Bulk Metallic Glass Upon Isothermal Annealing Near the Glass Transition Temperature

The stability of Zr41Ti14Cu12.5Ni10Be22.5 bulk metallic glass (BMG) upon isothermal annealing near the glass transition temperature has been investigated by using x-ray diffraction, differential scanning calorimetry, and the pulse echo overlap method. The density, elastic constants, and thermodynamic parameters as well as their annealing time dependence have been determined. The microstructural and properties changes of the annealed BMG were checked by acoustic measurement. Obvious structural and property changes were observed with prolonged annealing of the BMG near the glass transition temperature.

“神舟”四号中的流体物理实验

在多年地基研究的基础上，作为载人航天工程应用系统的有效载荷，在我国“神舟”四号飞船返回舱在轨飞行期间进行了大Marangoni数(Ma)液滴热毛细迁移空间微重力实验．实验中FC-75液和．5cst硅油分别为滴相和连续相实验流体介质，研究了在稳定、长时间的微重力环境中，不同温度梯度条件下液滴热毛细迁移的现象及特征．Marangoni数到达5500，很大地扩展了过去液滴热毛细迁移实验的Ma参数范围．实验结果表明，大Ma数液滴热毛细迁移特征规律复杂，迁移速度与YGB模型线性预测有明显的差别．文章介绍了液滴热毛细迁移研究进展，给出了此次空间实验的一些主要结果．讨论了大Ma液滴热毛细迁移的特征，并对自行研制的空间实验设备、实验过程进行了简要介绍．

气相爆轰波在障碍物上Mach反射后流场的分析

详细分析了气相爆轰波在斜劈上Mach反射后的流场。根据胞格结构的烟迹记录，得到了爆轰波Mach反射时三波点迹线与楔面的夹角X与楔角θ的定量关系，依此推算出爆轰波绕射楔块 时从规则反射向Mach反射转变的临界角范围。论文也分析了影响X角和Mach杆后压力的主要 因素。该结果有助于更深入了解爆轰波的本质，也为数值模拟气相爆轰波在障碍物上Mach反射现象提供了可靠的对照依据。

Carbon transition efficiency and process cost in high-rate, large-area deposition of diamond films by DC arc plasma jet

A new DC plasma torch in which are jet states and deposition parameters can be regulated over a wide range has been built. It showed advantages in producing stable plasma conditions at a small gas flow rate. Plasma jets with and without magnetically rotated arcs could be generated. With straight are jet deposition, diamond films could be formed at a rate of 39 mu m/h on Mo substrates of Phi 25 mm, and the conversion rate of carbon in CH4 to diamond was less than 3%. Under magnetically rotated conditions, diamond films could be deposited uniformly in a range of Phi 40 mm at 30 mu m/h, with a quite low total gas flow rate and high carbon conversion rate of over 11%. Mechanisms of rapid and uniform deposition of diamond films with low gas consumption and high carbon transition efficiency are discussed.

不可压N-S方程高效算法及二维槽道湍流分析

构造了基于非等距网格的迎风紧致格式,并将其与三阶精度的Adams半隐方法相结合,构造了求解不可压N-S方程高效算法。在数值模拟的基础上对二维槽道流动进行了分析,得到了Reynolds数从6 000到15 000的二维流动饱和态解(所谓"二维槽道湍流");定性及定量结果均与他人的数值计算结果吻合十分理想。对流场进行了统计分析,指出了"二维湍流"与三维湍流统计特性的区别。

The development of an inhomogeneous damage field in an elastic-plastic model

By making use of the evolution equation of the damage field as derived from the statistical mesoscopic damage theory, we have preliminarily examined the inhomogeneous damage field in an elastic-plastic model under constant-velocity tension. Three types of deformation and damage field evolution are presented. The influence of the plastic matrix is examined. It seems that matrix plasticity may defer the failure due to damage evolution. A criterion for damage localization is consistent with the numerical results.

空间发展混合流的大涡模拟

采用大涡模拟方法数值模拟了空间发展混合流，通过在平均流中引入小扰动，研究了混合流大涡结构的产生和演化过程，捕捉了展向涡的卷起、配对、合并，以及二次流向涡的出现等大尺度的三维拟序结构。与实验及直接数值模拟的结果相比，吻合程度较好。

Feasibility of Protein a for the Oriented Immobilization of Immunoglobulin on Silicon Surface for a Biosensor with Imaging Ellipsometry

The feasibility of using protein A to immobilize antibody on silicon surface for a biosensor with imaging ellipsometry was presented in this study. The amount of human IgG bound with anti-IgG immobilized by the protein A on silicon surface was much more than that bound with anti-IgG immobilized by physical adsorption. The result indicated that the protein A could be used to immobilize antibody molecules in a highly oriented manner and maintain antibody molecular functional configuration on the silicon surface. High reproducibility of the amount of antibody immobilization and homogenous antibody adsorption layer on surfaces could be obtained by this immobilization method. Imaging ellipsometry has been proven to be a fast and reliable detection method and sensitive enough to detect small changes in a molecular monolayer level. The combination of imaging ellipsometry and surface modification with protein A has the potential to be further developed into an efficient immunoassay protein chip.

利用微波散射估计海面气体传输速度

把作者提出的水气界面处气体传输率复合计算公式及适用于不同频率的微波散射反演公式〔1〕结合起来, 探索根据微波散射直接反演水气界面处气体传输 率的可行性。介绍了根据此反演方法所作的预测与Wanninkhof 和Bliven〔2〕在 Delft 大学100 m 长风水槽进行的微波散射和气体传输同步测量结果所进行的比 较, 比较结果是令人满意的。这表明: 从微波散射系数反演水气界面风速, 进而推求 水气界面处气体传输速度是全球尺度遥测估计水气界面气体传输的一条很有希望 的途径。在此采用的反演计算方法较之直接关联遥感数据与传输速度的预测方法 更有其普遍性和灵活性, 即它不依赖散射计工作频率, 同时还可依据不同的气体传输测量数据来源不断改进反演公式。