Effects of Cathode and Anode on Deposition of Trimethylsilane in Glow Discharge

DC cathodic polymerization of trimethylsilane (TMS) was carried out in plasma reactors with and without using anode assembly. In DC cathodic polymerization, the TMS plasma polymers are mainly deposited on the cathode (substrate) surface. As a result, fast deposition of TMS plasma polymers was easily achieved in DC cathodic polymerization as compared with AF or RF plasma polymerization. DC cathodic polymerization without using anode assembly has its advantageous features that the size and number of substrates (as cathodes) are not restricted by the size and the location of anode assembly. It was found that the maximum deposition rate on the cathode surfaces was obtained without anode assembly. The DC cathodic polymerization of TMS was conducted also in a large volume reactor with multiple cathodes (substrates). The same deposition mechanisms for DC cathodic polymerization with a single cathode also apply to the multiple cathodes. Uniform deposition on each cathode could be obtained with appropriate spacing of multiple cathodes and by adjusting the operational parameters, which are based on the current density and the system pressure.     

大型液相色谱分离过程FAD－SMT数学模型及其数值解

提出大型液相色谱分离过程ＦＡＤ－ＳＭＴ数学模型，把色谱分离连续性方程转变为对流扩散方程和常微分方程组，并提出模型的数值方法，分析了数值解的稳定条件和收敛条件以及空间和时间步长的选取。实验结果表明，ＦＡＤ－ＳＭＴ数学模型计算的液相色谱分离葡萄糖、果糖和分离甘露醇、山梨醇理论与实验流出曲线相吻合。灵敏度分析结果表明：相平衡常数比轴向扩散系数和总传质系数对色谱分离有较大的影响。     

Importance of the choice of assumptions and models in the estimation of analytical quality specifications

The validity of any model depends on its ability to imagine the situation or problem to which it is applied. Further, the assumptions made in relation to the model are determining for the actual outcome. Within the field of clinical biochemistry a lot of models for analytical quality specifications, based on a variety of concepts and ’clinical settings’, have been proposed. A hierarchical structure for application of these approaches and models has been agreed on at several occasions in 1999. In this hierarchy, the highest rank is given to evaluation of analytical quality specifications based on ’clinical settings’/’clinical outcome’ models, followed by specifications based on biological variation and on ’clinicians opinions’. This contribution, deals with the problems of combining random and systematic errors and the implications of application of different models to a variety of clinical settings. Received: 1 June, 2002 Accepted: 17 July 2002 Presented at the European Conference on Quality in the Spotlight in Medical Laboratories, 7–9 October 2001, Antwerp, Belgium     

Melting behavior of nylon 6 fiber in textiles

The melting process of constrained nylon 6 fibers has been studied to estimate the true melting point of its original crystals. The melting peak became simpler in shape and shifted to higher temperature with increasing fiber-axis restricting force. When heating rate, β, was increased, the temperature where the melting curve initially departs from its baseline, Tsm, decreased steeply in the range of 45 to 60°C min^-1, and increased linearly with increasing β above 60°C min^-1. By linear extrapolation of Tsm to 0°C min^-1, the temperature of ca 190°C was obtained for the melting temperature of the original nylon 6 crystals. This seems to correspond to the zero-entropy-production melting of the most imperfect crystallites of the nylon 6 fabric. This revised version was published online in July 2006 with corrections to the Cover Date.     

Zhang–Zhang Polynomials of Multiple Zigzag Chains Revisited: A Connection with the John–Sachs Theorem

Multiple zigzag chains Zm,n of length n and width m constitute an important class of regular graphene flakes of rectangular shape. The physical and chemical properties of these basic pericondensed benzenoids can be related to their various topological invariants, conveniently encoded as the coefficients of a combinatorial polynomial, usually referred to as the ZZ polynomial of multiple zigzag chains Zm,n. The current study reports a novel method for determination of these ZZ polynomials based on a hypothesized extension to John–Sachs theorem, used previously to enumerate Kekulé structures of various benzenoid hydrocarbons. We show that the ZZ polynomial of the Zm,n multiple zigzag chain can be conveniently expressed as a determinant of a Toeplitz (or almost Toeplitz) matrix of size m2×m2 consisting of simple hypergeometric polynomials. The presented analysis can be extended to generalized multiple zigzag chains Zkm,n, i.e., derivatives of Zm,n with a single attached polyacene chain of length k. All presented formulas are accompanied by formal proofs. The developed theoretical machinery is applied for predicting aromaticity distribution patterns in large and infinite multiple zigzag chains Zm,n and for computing the distribution of spin densities in biradical states of finite multiple zigzag chains Zm,n.     

手性5-(R)-(1′R,2′S,5′R)-孟氧基丁内酯并[3,4-b]-2(S)-6(R)-1-N-环己基氮杂环丙烷的合成及晶体结构

环己胺与手性元5-(R)-(1′R,2′S,5′R)-孟氧基-3-溴-2(5H)-呋喃酮的不对称M ichael加成/分子内亲核取代反应,得到含有两个新手性中心的氮杂环丙烷/稠合丁内酯标题化合物。对其进行了谱学表征和X-射线单晶衍射测定。标题化合物分子式为C20H33NO3,M r=335.47,三斜晶系,P1空间群,晶胞参数:a=5.438(11)。A,b=8.117(2)。A,c=11.572(2)。A,α=96.84(3)°,β=94.48(3)°,γ=101.86(3),°V=493.5(2)。A3,Z=1,D c=1.129g/cm3,R=0.0867,wR=0.2344。     

一种基于粒子群算法的DC-NOMA系统遍历容量优化方案

为提升设备到设备（Device-to-Device,D2D）辅助的协作非正交多址接入（Non-orthogonal Multiple Access,NOMA）中继系统的性能,以最大化系统遍历容量为目标建立优化模型,利用粒子群优化（Particle Swarm Optimization,PSO）算法设计最优功率分配策略,求出每个用户的最佳功率分配因子,从而得到系统遍历容量的最优值。仿真结果表明,所提出的基于PSO的功率分配方案不仅能提高系统容量,还可以降低用户的中断概率。     

无人机三维路径规划的粒子群混合算法

路径规划是无人机控制过程中的重要环节之一,现有基于粒子群等算法的传统路径规划方法存在容易陷入局部最优等问题,无法适应现实场景中复杂环境及高搜索速度的要求。针对已有方法的缺陷,提出了一种无人机路径规划的高性能细菌觅食-遗传-粒子群混合算法,以传统粒子群优化算法为基础,引入细菌觅食算法及遗传算法思想,提高算法计算速度与能力,同时考虑实际场景中无人机的运行约束,进一步提高了方法的可用性。最后,利用仿真实验验证了所提方法的有效性,并通过与传统方法对比证明了所提方法在运行时间、规划航程等方面的优越性。     

采用辅助转动装置的MIMO 系统双目标DPD 实验研究

文中介绍了一种双目标数字预失真(DPD)方案,并进行了实验研究。不增加系统复杂度的情况下, 可以有效地扩展MIMO 系统的线性化波束宽度。在发射机附近增设一个发射低功率信号的线性辅助转动装置,该 架构实现了MIMO 系统主波束线性化。实验平台由发射机系统和一个辅助转动装置组成,发射机天线阵列为1×4。 输入信号采用两个20 MHz 带宽峰均比分别为5. 7 dB 和5. 6 dB 的正交频分复用(OFDM)信号。实验研究结果表明, 采用了辅助转动装置的双目标DPD 方法后,邻信道功率比(ACPR)达到-50 dBc 以下的主波束线性化宽度可以扩展 到22°,同时信号归一化均方误差(NMSE)平均数值为-40 dB。该方案有效地拓宽了MIMO 系统线性化波束宽度。