微孔洞生长对板材拉伸过程中变形局部化的影响

本文在作者提出的含孔洞材料下限本构方程的基础上，采用了初始缺陷带模型对微孔洞生长及分布对板材拉伸过程中变形局部影响进行了，分析着重研究了细观损演化规律对变形局部化模式及临界应变的影响，并成功预测了ＡＩＳＩ４３４０钢板材拉伸试件变形局部化换稳为及失稳方向。     

Unique Orbital Normal Form for Vector Fields of Hopf-Zero Singularity

Normal forms for vector fields of Hopf-zero singularity in R³ are studied. Multiple Lie bracket method is used to give unique normal forms under both conjugacy and orbital equivalence for such vector fields with a generic quadratic part.Dedicated to Professor Shui-Nee Chow on the occasion of his 60th birthday.     

壁面材质和温度场对熔融硅润湿角的影响

本文建立了毛细模型, 采用微流动两相流水平集法计算了熔融态硅液与壁面的润湿角, 以人造金刚石作为壁面材料的计算结果与实验结果进行比较, 验证了该模型和计算方法的正确性. 在此基础上, 分别选用碳化硅、石墨和人造金刚石作为壁面材料, 探讨了不同壁面材料表面张力和壁面黏附力对润湿角的影响规律. 结果发现, 相同温度下的毛细力作用使得熔融硅液出现起伏上升现象; 润湿角均有不同程度的减小然后增大, 最终趋于稳定; 初始阶段, 由于气/熔融硅液表面张力与气/壁面表面张力之差变化较大, 液面起伏波动较大; 随后趋于稳定上升. 同时发现石墨作为壁面材料时, 以上变化更易趋于稳定. 该研究为熔体中生长晶体硅获得更稳定的生长环境提供了理论依据.     

Photoswitchable rotaxanes on gold nanoparticles

We studied rotaxanes that consisted of a molecular axle, with a photoactive 9-Aryl-9-methoxy-acridane moiety at one end, and a tetracationic ring of cyclobis(paraquat-p-phenylene) (CBQT(4+)). The aim of the study was to deposit the axle ends onto gold nanoparticles (AuNPs). First, we introduced thioctic acid into the axle molecules. Then, rotaxanes were deposited on AuNPs by two methods: 1) Pseudorotaxanes were deposited on the gold surface by forming rotaxanes with the AuNP as a terminator to prevent unthreading of the ring structure; and 2) a chain containing the thioctic ester was introduced into a complete rotaxane, and then it was deposited on the AuNP with the aid of an exchange process. The photoheterolysis of the acridane unit resulted in formation of the corresponding acridinium methoxide; this, in turn, could thermally react to return to the acridane moiety. Due to the creation of a positive charge, the ring moved from the acridane station to a second, evasive station within the axle. This switching cycle could also take place when deposited on the gold surface. However, on the gold surface, the ring movement associated with the switching process was unidirectional.     

Quantitative determination of bovine caseinoglycomacropeptide in infant formulas by ultra-high-performance liquid chromatography-electrospray-ionization mass spectrometry

An ultra-high-performance liquid chromatography-electrospray ionization coupled to mass spectrometry method has been developed for determining caseinoglycomacropeptide (CGMP) in infant formulas by selected ion reaction and area monitoring modes. The present study focused on the optimization of sample pretreatment, chromatographic resolution and mass spectrometry parameters. After a simple sample pretreatment, the two genetic variants of caseinoglycomacropeptide, CGMP(A) and CGMP(B), were separated using a BEH300 C(18) column by gradient elution. The established method was extensively validated by determining the linearity (R(2)>0.999), average recovery (95.8-118.4%), inter-day precision (relative standard deviation ≤7.81%) and intra-day precision (relative standard deviation ≤6.99%) based on two scan modes. To further verify the applicability of the method, 21 brands of commercial available infant formulas were analyzed. The results showed that the present method is selective, sensitive and reliable for separating and quantifying two genetic variants (CGMP(A) and CGMP(B)) of caseinoglycomacropeptide in infant formulas with complex matrix.     

磁控溅射(Ti,N)/Al纳米复合薄膜的微结构和力学性能

采用Al和TiN靶通过磁控共溅射方法, 制备了一系列Ti:N≈1的不同(Ti, N) 含量的铝基纳米复合薄膜, 利用X射线能量分散谱仪、X射线衍射仪、透射电子显微镜和纳米力学探针表征了薄膜的成分、 微结构和力学性能, 研究了(Ti, N)含量对复合薄膜微结构和力学性能的影响. 结果表明: Ti, N原子的共同加入使复合薄膜形成了同时具有置换固溶和间隙固溶特征的"双超过饱和固溶体", 薄膜的晶粒随着溶质含量的增加逐步纳米化, 并进一步形成非晶结构, 晶界区域形成溶质原子的富集区. 相应地, 复合薄膜的硬度在含1.8 at.%(Ti, N) 时就可迅速提高到3.9 GPa; 随着TiN含量的增加, 薄膜的硬度进一步提高到含17.1 at.%(Ti, N)时的8.8 GPa. 以上结果显示出Ti和N"双超过饱和固溶"对Al薄膜极其显著的强化效果.     

模拟激光制导的实验设计

通过固定激光器，改变光学系统的状态，实现了模拟激光制导的目的。     

Unique normal forms for Hopf-zero vector fields

We consider normal forms of Hopf-zero vector fields in $\text{R}{}^3$. Unique normal forms under conjugacy and orbital equivalence for the generic case are given. To cite this article: G. Chen et al., C. R. Acad. Sci. Paris, Ser. I 336 (2003).     

电子全息法三维物场逐层分析

本文叙述了一种三维物场的定量再现、分析方法,其中采用了电子全息法,它包括:1)三维物场全息图的数字记录,2)全息图面上复振幅分布的数字再现,3)三维物场的逐层再现。由此可以获得整个三维物场的信息,这一方法以CCD摄象机作为记录介质,然后把由CCD采集的数字全息图输入计算机,利用频谱滤波法经过傅里叶变换、频谱分离、反傅里叶变换再现出全息图面上的复振幅。在此基础上借助频域衍射公式可再现出任何一层(平行于全息图面)上的图象。这样,我们用这一数字再现和逐层分析的方法便可研究三维物场的一些特性,如物体在其中的位置等。整个再现过程是由计算机软件实现,其中采用了二维快速傅里叶变换算法,再现过程可在几分钟内完成。本文同时还给出了这一数字再现方法的空间分辨率,并且通过计算机模拟展示了一个理想三维物场的再现过程及再现结果。最后指出了这一方法存在的问题及未来的应用前景。     

Ti-Pd系超导电性的研究

本文给出了Ti-Pd系超导转变温度随合金成份的变化规律,指出Ti-Pd系中超导性是Pd在α-Ti中的固溶体所贡献的,结合这个合金系的相图,讨论了这些结果,认为Pd在α-Ti中的极限固溶度应有较高的数值。 关键词：