（S）-噻吗洛尔半水合物的合成及表征

为了开发β受体阻断剂新药（S）-噻吗洛尔半水合物，采用3-吗啉-4-氯-1，2，5-噻二唑为起始原料，经水解反应得到中间体1（3-吗啉-4-羟基-1，2，5-噻二唑）。中间体1与R-环氧氯丙烷发生醚化反应，经后处理及重结晶得到中间体2 {（R）-4-［4-（环氧乙烷-2-基甲氧基）-1，2，5-噻二唑-3-基］吗啉}。中间体2经胺化反应、马来酸成盐及重结晶得到（S）-马来酸噻吗洛尔。（S）-马来酸噻吗洛尔经游离、纯水转晶得到符合药典标准的（S）-噻吗洛尔半水合物，总收率14.05%且e.e.值为99.66%。最终成品经IR、1H-NMR、13C-NMR、MS、TGA、DSC表征，并优化各步反应条件。结果表明:以三乙胺为醚化反应缚酸剂75 ℃反应最佳；以乙醇为胺化反应溶剂46 ℃反应16 h最佳；S-噻吗洛尔的转晶拆分以水作溶剂，比传统不对称合成工艺安全稳定，操作简单，适合工业化生产。     

不同形貌碳酸钙的制备及其对PVC薄膜力学性能的影响

选用偏钒酸铵、聚乙二醇、十六烷基三甲基溴化铵、焦磷酸钠十水和聚乙烯吡咯烷酮作为碳酸钙形貌控制剂，以氯化钙和碳酸钠为原料，用氯化法制备得到了片状、菱形、棒状、球状和立方体状5种不同形貌碳酸钙微粒，并研究不同形貌碳酸钙颗粒形态对软质聚氯乙烯（PVC）薄膜力学性能的影响。结果表明，不同形貌碳酸钙均提高了PVC薄膜的力学性能，PVC薄膜拉伸强度和断裂伸长率均提高显著；其中，棒状形貌碳酸钙对PVC薄膜力学性能的提高效果最好，拉伸强度达到了27.11 MPa；菱形碳酸钙改性PVC薄膜的断裂伸长率最高，为98.23 %。     

Stereo matching cost computation based on nonsubsampled contourlet transform

A new matching cost computation method based on nonsubsampled contourlet transform (NSCT) for stereo image matching is proposed in this paper. Firstly, stereo image is decomposed into high frequency sub-band images at different scales and along different directions by NSCT. Secondly, by utilizing coefficients in high frequency domain and grayscales in RGB color space, the computation model of weighted matching cost between two pixels is designed based on the gestalt laws. Lastly, two types of experiments are carried out with standard stereopairs in the Middlebury benchmark. One of the experiments is to confirm optimum values of NSCT scale and direction parameters, and the other is to compare proposed matching cost with nine known matching costs. Experimental results show that the optimum values of scale and direction parameters are respectively 2 and 3, and the matching accuracy of the proposed matching cost is twice higher than that of traditional NCC cost.     

二水硫酸钙间接矿化二氧化碳CTAB对碳酸钙晶型的影响

提升产品附加值对改善二氧化碳矿化过程的经济性具有重要意义。在二水硫酸钙与碳酸铵溶液进行间接矿化反应过程中,采用十六烷基三甲基溴化铵（CTAB）为晶型调节剂,可以获得球霰石晶型的碳酸钙。系统研究了反应时间、反应温度、CTAB加入量对碳酸钙晶型和形貌的影响,通过X射线衍射（XRD）、扫描电镜（SEM）和红外光谱（FT-IR）对碳酸钙的晶型、形貌进行了表征。结果表明：反应过程为先形成亚稳定相的球霰石,再向热力学最稳定的方解石相转化;添加CTAB能够明显地增强球霰石的稳定性;较低温度有利于球霰石的形成;在反应温度为30 ℃、二水硫酸钙和碳酸铵加入量均为0.1 mol/L、CTAB加入量为0.54 mmol/L条件下,碳酸钙中球霰石占比高达80%以上;CTAB在球霰石表面上的吸附降低了其表面能,从而抑制了球霰石向方解石的转化。     

Adaptive backstepping repetitive learning control design for nonlinear discrete‐time systems with periodic uncertainties

This paper addresses a tracking problem for uncertain nonlinear discrete‐time systems in which the uncertainties, including parametric uncertainty and external disturbance, are periodic with known periodicity. Repetitive learning control (RLC) is an effective tool to deal with periodic unknown components. By using the backstepping procedures, an adaptive RLC law with periodic parameter estimation is designed. The overparameterization problem is overcome by postponing the parameter estimation to the last backstepping step, which could not be easily solved in robust adaptive control. It is shown that the proposed adaptive RLC law without overparameterization can guarantee the perfect tracking and boundedness of the states of the whole closed‐loop systems in presence of periodic uncertainties. In addition, the effectiveness of the developed controller is demonstrated by an implementation example on a single‐link flexible‐joint robot. Copyright © 2014 John Wiley & Sons, Ltd.     

Detectability in stochastic discrete event systems

A discrete event system possesses the property of detectability if it allows an observer to perfectly estimate the current state of the system after a finite number of observed symbols, i.e., detectability captures the ability of an observer to eventually perfectly estimate the system state. In this paper we analyze detectability in stochastic discrete event systems (SDES) that can be modeled as probabilistic finite automata. More specifically, we define the notion of A-detectability, which characterizes our ability to estimate the current state of a given SDES with increasing certainty as we observe more output symbols. The notion of A-detectability is differentiated from previous notions for detectability in SDES because it takes into account the probability of problematic observation sequences (that do not allow us to perfectly deduce the system state), whereas previous notions for detectability in SDES considered each observation sequence that can be generated by the underlying system. We discuss observer-based techniques that can be used to verify A-detectability, and provide associated necessary and sufficient conditions. We also prove that A-detectability is a PSPACE-hard problem.     

中子平衡节块离散纵标法及CMFD加速技术研究

本文基于横向积分离散纵标方程,解析得到横向积分通量中出射通量与入射通量的关系,并根据类似于扩散方程节块展开法的输运节块中子平衡方程形式,得到了一种高效的节块离散纵标法数值迭代策略。数值结果表明,本文提出的方法可行且数值结果正确。此外,粗网有限差分(CMFD)加速技术在节块离散纵标法中也取得了非常好的应用效果。     

Investigating heat conduction in a sphere with heat absorption using generalized Caputo fractional derivative

In this paper, we study the ρ-Laplace transform and the finite sin-Fourier transform as powerful tools in solving fractional differential equations with generalized Caputo derivative. We use these transforms to solve the time-fractional heat equation with a generalized Caputo fractional derivative associated with heat absorption in spherical coordinates. We obtain the solutions in two cases of Dirichlet boundary conditions. The effect of the parameter $\rho$, which characterizes the generalized Caputo derivative is illustrated through some numerical examples.     

The Investigation of the Fractional-View Dynamics of Helmholtz Equations Within Caputo Operator

It is eminent that partial differential equations are extensively meaningful in physics, mathematics and engineering. Natural phenomena are formulated with partial differential equations and are solved analytically or numerically to interrogate the system’s dynamical behavior. In the present research, mathematical modeling is extended and the modeling solutions Helmholtz equations are discussed in the fractional view of derivatives. First, the Helmholtz equations are presented in Caputo’s fractional derivative. Then Natural transformation, along with the decomposition method, is used to attain the series form solutions of the suggested problems. For justification of the proposed technique, it is applied to several numerical examples. The graphical representation of the solutions shows that the suggested technique is an accurate and effective technique with a high convergence rate than other methods. The less calculation and higher rate of convergence have confirmed the present technique’s reliability and applicability to solve partial differential equations and their systems in a fractional framework.