Electrostatic Control of Structure in Self‐Assembled Membranes

Self‐assembling peptide amphiphiles (PAs) can form hierarchically ordered membranes when brought in contact with aqueous polyelectrolytes of the opposite charge by rapidly creating a diffusion barrier composed of filamentous nanostructures parallel to the plane of the incipient membrane. Following this event, osmotic forces and charge complexation template nanofiber growth perpendicular to the plane of the membrane in a dynamic self‐assembly process. In this work, we show that this hierarchical structure requires massive interfacial aggregation of PA molecules, suggesting the importance of rapid diffusion barrier formation. Strong PA aggregation is induced here through the use of heparin‐binding PAs with heparin and also with polyelectrolytes of varying charge density. Small angle X‐ray scattering shows that in the case of weak PA‐polyelectrolyte interaction, membranes formed display a cubic phase ordering on the nanoscale that likely results from clusters of PA nanostructures surrounded by polyelectrolyte chains.     

New method in synthesis of nano uranyl(VI) Schiff base complexes: Characterization and electrochemical studies

This study presents a new method in synthesis of nano uranyl Schiff base complexes. In this method slow addition of dilute uranyl(VI) acetate solution to dilute Schiff base solution following the reflux for about 24 h, yields nano uranyl(VI) Schiff base complexes. Characterization of Schiff base ligands and nano uranyl complexes has been done using ¹H NMR, IR, UV–vis spectroscopy, elemental analysis. Schiff base ligands were synthesized by the condensation of one mole 3,4-diaminobenzophenone and two moles salicylaldehyde or substituted salicylaldehyde (3-OMe, 4-OMe, 5-OMe, 5-Br, 5-Cl). The electrochemical properties of the uranyl(IV) complexes were investigated by cyclic voltammetry. A good correlation was observed between the oxidation potentials and the electron withdrawing character of the substituents on the Schiff base ligands, according to the following trend: 5-MeO < H < 5-Br ≈ 5-Cl. Also the effect of the position of the substituted groups of Schiff base on the anodic potentials is as follows: 5-OMe < 3-OMe < 4-OMe.     

Application of strength reduction method to dynamic anti-sliding stability analysis of high gravity dam with complex dam foundation

Considering that there are some limitations in analyzing the anti-sliding seismic stability of dam-foundation systems with the traditional pseudo-static method and response spectrum method,the dynamic strength reduction method was used to study the deep anti-sliding stability of a high gravity dam with a complex dam foundation in response to strong earthquake-induced ground action.Based on static anti-sliding stability analysis of the dam foundation undertaken by decreasing the shear strength parameters of ...     

Categorically defined targets trigger spatiotemporal visual attention.

Transient attention to a visually salient cue enhances processing of a subsequent target in the same spatial location between 50 to 150 ms after cue onset (K. Nakayama & M. Mackeben, 1989). Do stimuli from a categorically defined target set, such as letters or digits, also generate transient attention? Participants reported digit targets among keyboard symbols in a changing array of 8 items. When 1 target preceded a second target in the same location at a stimulus onset asynchrony of 107 ms (but not 213 ms), the second target was reported more often than in a condition in which there was no leading target. When the 2 targets were at different locations, report of the second target was impaired. With both letters and digits as targets, the enhancement effect was shown not to be due to category priming. Critically, the attentional benefit was present whether or not participants reported the leading target. Transient attention, contingent attentional capture, popout, and Lag 1 sparing in the attentional blink may involve a common mechanism for orienting processing resources towards salient and task relevant stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

某车型制件托架拼板“毛毛虫”国产化模具的研究和工艺分析

对V362车型制件托架拼板国产化模具进行了研究和工艺分析,使用特殊设计理念和合理布局及完善的切边冲孔思路,达到了工业化生产的基本要求。将切边等3道工序的内容合并为一道工序,减少了模具数量,并使用侧斜楔侧冲孔侧修边,方便了制件操作,从而使操作中节约了成本,提高竞争力。     

复杂电磁环境下微弱目标探测技术研究

利用广播、电视以及卫星等信号为照射源的无源雷达,在复杂电磁环境下的干扰信号严重影响了远距离微弱目标的探测,为此提出了空时二维反干扰处理和二维长时相干积累技术。重点分析最大信干噪比（MSINR）准则的空域自适应零点形成技术和基于遗忘因子的改进型递推最小二乘（RLS）时域自适应处理算法,解决了微弱目标长时积累的可实现问题。最后在实验系统中进行了实际数据的仿真和验证,提高了微弱目标的检测概率,同时大目标的信杂比也提高了5 dB 以上,在实际工程中得到了很好的应用。     

一种适应复杂电磁环境的重频跟踪方法

针对现代电子战日益复杂的电磁环境以及不断涌现的新体制雷达,本文采用脉冲预测的方法对指定的雷达信号进行重频跟踪。由于脉冲预测的特征规律与目标雷达重复周期精确一致,重频跟踪器解决了如何在复杂电磁环境下进行实时信号跟踪的问题,并且能够适应多种不同体制的雷达信号。     

Numerical Simulation of Currents Distribution Along Grounding Grid Buried in Horizontal Multi-layered Earth in Frequency Domain Based Dynamic State Complex Image Method

A new mathematical model for accurately computing currents along a grounding grid buried in a horizontal multi-layered earth model has been developed in this article, which is a hybrid of Galerkin’s method of moment and the conventional nodal analysis method; the propagation effect of an electromagnetic wave has been considered. The dynamic state complex image method and closed form of Green’s function of a dipole or monopole in the multi-layered earth model are introduced to enhance efficiency of the method calculation; meanwhile, an analytical formula for mutual induction and impedance coefficients calculation have been adopted to accelerate the calculation. Finally, some numerical results about the distribution of an electromagnetic field and currents along a grounding grid have been discussed, and some conclusions have been obtained.     

考虑元件综合重要度的电网安全性风险评估方法

从系统学角度出发,综合考虑系统中元件的结构属性、状态属性及社会属性,提出一种考虑元件综合重要度的电网安全性风险评估方法。综合元件结构重要度因子模型与元件状态灵敏度因子模型构建元件综合重要度模型,该模型克服了传统风险评估方法中对于不同元件的重要度无法表征的不足;综合考虑电网结构与状态,建立表征电网潮流分布均衡性与负荷损失的严重度模型,完善安全性风险评估指标体系。仿真结果表明,相较于传统方法,该方法对电网N-1故障风险排序更为合理,对N-k故障序列分级风险辨识度更高。     

多逆变器并联下的输出阻抗分析和改进下垂控制策略研究

在分析低压微电网多逆变器并联基本原理的基础上,引入虚拟复阻抗,并给出一种改进的下垂控制策略。通过设计虚拟复阻抗参数值,使逆变器等效输出阻抗在工频处呈阻性,提高逆变器并联的均流效果。采用电容电压和电容电流双环控制,首先通过研究虚拟复阻抗中参数选择对于抑制环流的影响,进而确定基本的参数大小。其次,通过对比输出阻抗幅频特性,具体分析在不同参数情况下对逆变器输出阻抗特性的影响。再通过理论详细分析和计算,给出一种改进的下垂控制方法,并与虚拟复阻抗结合。最后,搭建仿真模型,选取上述经过理论研究的参数值,仿真验证分析虚拟复阻抗中参数对输出电压的影响以及改进下垂控制的可行性,证实所提方法的有效性和正确性。