亲水性两性离子聚合物刷的构象与结构

本文应用分子场理论,研究暴露于水蒸气中的亲水性两性离子聚合物(HP)刷的构象与结构.理论模型考虑HP-水(P-W)氢键和水-水(W-W)氢键效应,以及HP单体之间的偶极-偶极相互作用.研究发现,P-W与W-W氢键决定着HP的水合性,P-W氢键形成,会诱导HP刷溶胀.我们通过考察HP单体间的偶极-偶极相互作用发现,随着偶极-偶极相互作用增强,HP链在垂直培基表面沿着链方向,形成了结节状结构.这是由于HP单体之间的偶极-偶极静电吸引作用导致单体间汇聚结节,这种结节在刷内产生了较强的排斥体积作用,因此,这种HP刷具有抗污性能.在较高的接枝密度环境下,由于HP链间单体之间的偶极-偶极静电吸引作用,会形成链间单体-单体的结节,在刷内形成结节网络状凝胶结构,这种结构的出现,会使得HP刷呈现极强的抗污性.另外,当体系中水蒸气浓度增加、水合相互作用增强时,增加的P-W氢键将平衡HP单体之间的偶极-偶极相互作用,使得结节解开,聚合物链伸展.我们的理论结果符合实验观测,由此表明,P-W氢键效应,以及HP单体之间的偶极-偶极相互作用决定着HP刷的构象转变和结构特性,刷内出现的两性离子聚合物链内单体间的结节和链间单体结节状凝胶结构,是两性离子聚合物刷呈现较强抗污性的本质特性.     

Deep level transient spectroscopy investigation of deep levels in CdS/CdTe thin film solar cells with Te:Cu back contact

Deep levels in Cds/CdTe thin film solar cells have a potent influence on the electrical property of these devices. As an essential layer in the solar cell device structure, back contact is believed to induce some deep defects in the CdTe thin film. With the help of deep level transient spectroscopy (DLTS), we study the deep levels in CdS/CdTe thin film solar cells with Te:Cu back contact. One hole trap and one electron trap are observed. The hole trap H1, localized at E_v+0.128~eV, originates from the vacancy of Cd (V_Cd. The electron trap E1, found at E_c-0.178~eV, is considered to be correlated with the interstitial Cu_i⁼ in CdTe.     

Coherent beam combination of adaptive fiber laser array with tilt-tip and phase-locking control

We present an experimental study on tilt-tip(TT) and phase-locking(PL) control in a coherent beam combination(CBC) system of adaptive fiber laser array.The TT control is performed using the adaptive fiber-optics collimator(AFOC),and the PL control is realized by the phase modulator(PM).Cascaded and simultaneous controls of TT and PL using stochastic parallel gradient descent(SPGD) algorithm are investigated in this paper.Two-fiber-laser-,four-fiber-laser-,and six-fiber-laser-arrays are employed to study the TT and PL control.In the cascaded control system,only one high-speed CMOS camera is used to collect beam data and a computer is used as the controller.In a simultaneous control system one high-speed CMOS camera and one photonic detector(PD) are employed,and a computer and a control circuit based on field programmable gate array(FPGA) are used as the controllers.Experimental results reveal that both cascaded and simultaneous controls of TT using AFOC and PL using PM in fiber laser array are feasible and effective.Cascaded control is more effective in static control situation and simultaneous control can be applied to the dynamic control system directly.The control signals of simultaneous PL and TT disturb each other obviously and TT and PL control may compete with each other,so the control effect is limited.     

故障树模块化在装甲车辆灭火系统故障诊断中的应用

为了实现装甲装备灭火系统故障的快速诊断,提出了一种故障树模块化分析方法;对灭火系统故障树进行深度优先最左遍历,并记录遍历过程,按照遍历顺序对故障树中的每个事件进行标定,并将灭火系统故障树划分为相互独立的模块,依据划分的模块可以通过故障现象对模块内的故障进行排查及修复;实验结果分析表明,该方法可以快速修复模块故障,恢复系统功能,简化了以往对灭火系统所有子事件遍历查错的繁琐过程。该方法同样可以计算故障模块的失效概率,并可以实现故障模块的整体更换,恢复系统性能;证明了故障树模块化方法在灭火系统故障诊断中具有较高的效率,简化了灭火系统诊断流程,在装甲车辆其他系统故障诊断中具有借鉴作用,符合现代作战对于装备保障的需求。     

Effect of H impurity on misfit dislocation in Ni-based single-crystal superalloy： molecular dynamic simulations

The effect of H impurity on the misfit dislocation in Ni-based single-crystal superalloy is investigated using the molecular dynamic simulation.It includes the site preferences of H impurity in single crystals Ni and Ni 3 Al,the interaction between H impurity and the misfit dislocation and the effect of H impurity on the moving misfit dislocation.The calculated energies and simulation results show that the misfit dislocation attracts H impurity which is located at the γ/γˊinterface and Ni₃ Al and H impurity on the glide plane can obstruct the glide of misfit dislocation,which is beneficial to improving the mechanical properties of Ni based superalloys.     

Improvement of amine-modification with piperazine for the adsorption of CO2

Both selectivity and capacity of CO₂ adsorption were considerably increased when PZ (piperazine) was added in MDEA (methyldiethylamine) that used to modify the surface of silica gels. The adsorbent saturated with CO₂ was regenerated at ambient temperature through nitrogen purge. A set of PSA (pressure swing adsorption) operation with 200 cycles was carried out and applicability of the modified adsorbent was thus illustrated. The CO₂ content in the column-top stream decreased from 13% to below 0.05% at steady state.     

光学扫描全息术中的孪生像噪音及消除

阐述了光学扫描全息术的基本原理,分析了孪生像噪音的来源,提出了一种新的数字滤波方法.计算机仿真结果表明:孪生像噪音以振荡形式传播,降低了重构图像的信噪比,影响了重构图像的分辨率;用电子复用技术,即用复全息图函数代替实全息图函数的方法可以有效地消除孪生像噪音;采用单一通道对信号进行处理,即只用一个实全息图函数,通过数字滤波方法同样可以消除孪生像噪音,该方法简便、实用而有效.     

加强型Bi-2212超导股线有限元拉伸性能分析

为探究加强型Bi-2212超导股线的力学性能以及不锈钢包带对超导股线力学性能的影响,运用Ansys软件建立加强型Bi-2212超导股线的三维模型,采用有限元分析方法,对其机械结构进行仿真,模拟高温高压热处理后轴向受拉形变量和应力应变分布情况。仿真结果显示,在同样施加100 N拉力的情况下,与超导原线（Bi-2212超导线）相比,密绕Ni₈₀Cr₂₀包带后的加强型Bi-2212超导股线轴向受拉形变程度减小,约10%;应力应变均降低,约30%。采用Ni₈₀Cr₂₀作为外包带制成的加强型Bi-2212超导股线力学性能显著,是未来超导线发展方向之一。     

咪唑类氮氧自由基的ESR波谱的酸度相关性-pH自旋探针应用研究之一

根据咪唑类氮氧自由基的结构特性合成了一系列的pH自旅探针,其ESR波谱参数均在一定范围内与介质的酸性呈明显的相关性.可望为较精确地测量化学胶束、细胞等微观体系的pH值开辟一个新的途径.本文研究了灵敏变化的pH范围与取代基的关系,得到了5种自旅探针的ESR参数-pH曲线、pKa值以及Hanmmett相关图,分析了如何通过改变取代基合成出不同pH变化范围并适用于不同生物和化学体系的pH自旅探针,最终达到付诸应用的目的.     

A spectroscopic method for determining thickness of quartz wave plate

A spectroscopic method to determine thickness of quartz wave plate is presented. The method is based on chromatic polarization interferometry. With the polarization-resolved transmission spectrum (PRTS)curve, the phase retardation of quartz wave plate can be determined at a wide spectral range from 200 to2000 nm obviously. Through accurate judgment of extreme points of PRTS curve at long-wave band, the physical thickness of quartz wave plates can be obtained exactly. We give a measuring example and the error analysis. It is found that the measuring precision of thickness is mainly determined by the spectral resolution of spectrometer.