Structural analysis of an impurity of the drug landiolol

In a course of development and preparation of landiolol (1a), a known ultra‐short‐acting β‐blocker, process quality control by HPLC and LC‐MS analysis consistently showed an impurity peak ranging from 0.05% to 0.15 % and exhibiting a molecular mass m/z 887. To identify the hitherto unknown impurity, we prepared one of the possible landiolol derivatives with the same molecular mass for proper spectral characterization (NMR and MS). Its equivalence with the unknown impurity was then confirmed by LC‐MS analysis. Ultimately, using fragmentation patterns in LC‐MS and selective two‐dimensional NMR experiments, the structure of the impurity was assigned as [(4S)‐2,2‐dimethyl‐1,3‐dioxolan‐4‐yl]methyl 3‐{4‐[(2S)‐2‐hydroxy‐3‐(3‐{4‐[(2S)‐2‐hydroxy‐3‐[(2‐{[(morpholin‐4‐yl)carbonyl]amino}ethyl)amino]propoxy]phenyl}‐N‐(2‐{[(morpholin‐4‐yl)carbonyl]amino}ethyl)propanamido)propoxy]phenyl}propanoate (2). It was found that the impurity was present in two rotameric forms at room temperature. The synthesis and NMR characterization of (2) are discussed. Copyright © 2014 John Wiley & Sons, Ltd.     

电子错位散斑研究

本文从理论上分析了错位散斑实现电子干涉的可行性,推导了摄象机光靶接收的错位散斑的光强表达式,分析了电子干涉条纹的可见度,提出并实现了电子错位散斑技术的三种方法,即实时法,双曝光法和实时时间差法。获得了位移梯度等值条纹的电子干涉图。     

Gradient plasticity with the tangential-subloading surface model and the prediction of shear-band thickness of granular materials

An extended gradient elastoplastic constitutive equation is formulated, which is capable of describing the plastic strain rate due to the rate of stress inside the yield surface and the inelastic strain rate due to the stress rate component tangential to the subloading surface by incorporating the tangential-subloading surface model. Based on the extended constitutive equation, the post-localization analysis of granular materials is performed to predict the shear-band thickness. It is revealed that the shear-band thickness is almost determined by the gradient coefficient characterizing the inhomogeneity of deformation, although the stress–strain curve is strongly dependent on material properties.     

Influence of surface effects on fatigue of microcracks nucleation

Cyclic plastic slips in persistent slip bands (PSBs) at the free surface and in the bulk are evaluated for high-cycle fatigue of polycrystals. Analytical results are obtained for PSBs in the bulk and for surface type A PSBs, but the finite element method is used for surface type B PSBs. For practical applications, the results are presented in the form of amplification factors, which are almost insensitive to the PSB aspect ratio and other material parameters. These values are then used to include surface effects in an evaluation of the post-saturation number of cycles to crack nucleation. Some environmental effects are also taken into account. An energy balance criterion is used, and the effect of microslip irreversibilities is evaluated on a statistical basis.     

非均匀性对材料分叉的作用

利用数值方法研究材料空洞化和承受应力沿板厚分布的非均匀性对材料分叉（平板中平面剪切带和表面皱曲）的作用。     

材料分叉的数值分析

通过与解析解法相对比，本文说明了分析材料分叉时采有数值法的特点．文中揭示了在单向和弱双向加载条件下材料分叉（平面剪切带和表面皱曲）的一些特征．单向拉伸的实验表明，所计算的临界值是合理的．     

非线性粘弹性方柱的有限剪切

利用有限线性粘弹性的一种简化形式，研究了方柱的有限剪切，并采用丁苯橡胶的有关实验数据，进行了数值计算，考究了材料的非线性特征。     

数字闭环光纤陀螺死区机理分析

结合工程实际，对基于集成光学多功能芯片的数字闭环光纤陀螺中的死区机理进行理论分析，并进行了实验验证。相位调制器的模拟驱动电压信号在数字反馈阶梯波复位作用下能产生不同的工作模式，探测器的输出微弱信号因此受到幅值和相位均不同的电子串扰。以方波调制和四态波调制为例，研究了光纤陀螺中电子串扰的作用方式、电子串扰的转换方式和形成死区的过程等问题。在上述基础上，根据需要设计了专门的可编程的光纤陀螺高速数据采集电路，对死区机理进行了研究试验。最后还从优化陀螺电路印制板设计和优化信号调制解调算法等方面进行阐述，以解决数字闭环光纤陀螺死区问题。     

数字剪切散斑相关条纹图的形成及其分析

本文提出了用线性相关计算形成高可见度的数字剪切散斑相关条纹图的方法，为相关条纹图的自动分析奠定了良好的基础。文中还推导了附加位相与物光反射镜转角的关系，使精确地计算附加位相成为可能。同时还介绍了任意附加位相的三步相移技术。最后给出了用线性相关计算法形成的相关条纹图及计算出的位相图。     

岩土介质中局部化变形研究的一些新进展

岩土中的剪切带产生通常是断裂和失稳的前兆, 常引起滑坡等地 质灾害, 对油气或水合物等矿藏的开采容易导致压实带形成. 压实带的产生使岩土孔隙减小, 颗粒破碎, 从而导致沉陷、对油气的挤压等.本文重点对剪切带的宽度和压实带的研究现状作综述, 阐述在该问题的研究上从微观 观测到宏观表述的重要性. 通过分析, 认为还有如下问题值得研究: 怎样 准确得出局部化变形带的宽度和方向?局部化变形带形成后孔隙水和油气的渗流会发生什么 变化?颗粒层次的微结构特性是通过什么方式影响宏观表现的等等.