一类差分方程的渐近概周期序列解的存在性

利用渐近概周期函数以及序列的定义和基本性质,得出下面离散系统存在正渐近概周期序列解唯一性的充分条件.     

高维度满速率的宏分集空时编码方案

为了适应宏分集传输中高天线数的要求,提出一种高维度满速率的空时编码方案. 这种高维度编码可以达到满速率传输,且其最大似然译码复杂度可控,只需对(发射天线数/2)个实数符号联合最大似然译码. 对该编码的等效信道相关矩阵进行分析后得出结论：等效信道右奇异矩阵为常数矩阵. 提出一种具有单符号线性译码复杂度的无反馈要求的预处理传输机制,使译码复杂度大大降低. 仿真结果表明,相比于最小译码复杂度编码以及其他宏分集传输方案,如循环延迟分集,高维度满速率编码方案的性能有一定提升.     

在柠檬酸中制备大孔径阳极氧化铝模板的方法

现有的报道普遍认为柠檬酸作为阳极氧化铝的反应溶液只能制备出致密型的氧化铝膜。笔者发现柠檬酸作为反应溶液在350V直流电压下可制备出孔径600nm左右的多孔型的阳极氧化铝模板(AAO)模板.通过与以往研究结果比较发现要想获得较大孔径的AAO模板需要选择较小电离常数的酸液.在去除阻挡层时,磷酸腐蚀了模板的反面,导致模板反面的孔径大约是正面孔径的一倍.     

光谱法研究Ni[S2P（OCH2CH2Ph）2]2与α,α＇-联吡啶加合反应

利用紫外光谱法研究了Ni[S2P（OCH2CH2Ph）2]2与α,α-联吡啶的加合反应。研究发现Ni[S2P（OCH2CH2Ph）2]2与α,α-联吡啶形成1∶1型加合物,在25℃的苯溶剂中,加合物的离解度α=0.07,稳定常数K稳^θ=2.1×10^6。     

新型双BUCK恒流源的研究

为解决电源设计中片面追求高频化所带来的一系列问题,设计了一种双BUCK拓扑结构的开关恒流源。分析了其工作原理,并用Saber软件对电路进行仿真分析,再通过实验验证了其正确性、可行性和有效性。     

摩擦式提升机安全性能的初步分析

介绍了多绳摩擦式提升机的工作原理,对摩擦式提升机的安全性能进行了分析,探讨了摩擦式提升机的防滑安全系数和具体的防滑安全措施,并对摩擦提升机的主要优缺点进行了比较．     

Introduction of fluorin into PBO polymer chains: Toward higher thermal stability and lower dielectric constant

A series of novel fluorinated benzoxazole polymers (6FPBO's) with high thermal stability and low dielectric constant were synthesized by copolymerization of 1,3-diamino-4, 6-dihydroxybenzene dihy-drochloride (DAR), 1,4-benzenedicarboxylic acid (PTA) and various amount of 4'4- (hexafluoroisopro-pylidene) bis (benzoic acid) (BIS-B-AF) in the medium of polyphosphoric acid (PPA). 6FPBO fibers were then obtained via dry-jet wet-spinning technique and characterized by means of Fourier transform infrared (FTIR) spectra, thermogravimetric analysis (TGA), single fiber tensile testing machine and scanning electron microscopy (SEM). FTIR spectrum of 6FPBO fibers indicated that the fluorine groups had been incorporated into PBO molecular chains successfully. TGA curves revealed that 6FPBO fibers possessed high thermal stability just as pure PBO fibers. Moreover, dielectric constant spectrum of 6FPBO exhibited that the polymers had low dielectric constant, especially in the range of high- frequency.     

Self-assembled patterned CoFe2O4-SrRuO3 electrodes: Enhanced functional properties by polar nano-regions reorientation

Epitaxial CoFe₂O₄ (CFO) and SrRuO₃ (SRO) nanopillar heterostructures were deposited on Pb(Mg_1/3Nb_2/3)_0.70Ti_0.30O₃ (PMN-30PT) single crystal substrates by switch pulsed laser deposition (SPLD). Since the CFO nanopillars are insulating, and the SRO matrix conductive, this self-assembled nanopillar heterostructure served as a patterned electrode on PMN-PT, which then enhances the dielectric and piezoelectric constant of the substrate. Cross-sectional electron microscopy images revealed the formation of a nanopillar heterostructure layer with CFO nanopillars within a SRO matrix. AFM and XRD revealed good topography and epitaxy, indicating a high quality SRO-CFO self-assembled nanopillar structure. Using a SRO-CFO thin film patterned electrode, PMN-PT was found to have a notably higher (30%) dielectric constant with increasing electric field and enhanced transverse broadening in reciprocal spacing mapping (RSM) scans.     

恒压供水系统的调试及验证

介绍恒压供水系统的调试及验证.     

浅谈液压式闸门的开度测量方法

【】结合闸门控制设计经验,针对液压式闸门,对不同型式闸门开度测量方法进行了比较,重点介绍了用恒力收带式传感器测量液压式闸门开度的方法,并通过应用案例说明了该方法的有效性和实用性,期望能为今后设计选型提供参考。