基于P89C669微控制器的MODBUS协议转换器设计与实现

基于P89C669微控制器和计算机数据通信技术,设计了MODBUS协议转换器,实现了MODBUS网络的主控设备与RTU(远程终端单元)之间的数据转换,并在电力系统220 kV主变风冷控制中用于变电所站内自动化监控计算机系统的MODBUS网络和PLC(可编程逻辑控制器)的数据通信,使站内自动化监控系统可根据主变油温、负荷电流等运行参数对风冷机组和油泵进行实时调控。     

Minkowski结构运算与顺序滤波

本文从Minkowski结构运算出发,导出了一系列具有实际意义的几何结构函数和特征参 量,并拓广二值图象的结构运算到多值图象(即顺序滤波)和多维图象,最后略述结构运算与顺 序滤波的若干应用.     

我国互联网的现状及若干问题刍议

介绍了互联网及其在我国的发展历程和目前现状，指出了我国互联网建设中存在的法制体系不完善、发展不均衡、缺乏规范管理、网络安全问题日益突出、互联网技术落后的若干问题。针对这些问题，对我国互联网建设发表了几点看法。     

《塔式起重机混凝土基础工程技术规程》JGJ/T187-2009编制及说明

<塔式起重机混凝土基础工程技术规程>JGJ/T187-2009于2010年7月1日起实施.本规范编制过程中正值我国塔式起重机安全事故高发期,事故原因大多是对塔式起重机安全技术理论研究不足和相关规范存在缺陷.结合塔式起重机混凝土基础工程技术在我国发展的现状,介绍了规程编制背景及编制过程.主要介绍了技术规程的主要内容和特点,并简要介绍了配套开发的设计计算软件.     

PEMFC modeling based on characterization of effective diffusivity in simulated cathode catalyst layer

Oxygen diffusion in the cathode catalyst layer (CCL) is crucial to the high performance of polymer electrolyte membrane fuel cells (PEMFCs), especially in high current density or concentration loss regions. Recently, PEMFC performance has been reported to be enhanced by increasing CCL pore size and pore volume due to the reduction of diffusion resistance by capillary water equilibrium [Yim et al., Electrochimica Acta 56 (2011) 9064–9073]. Herein, we simulate these experimental results utilizing a new one-dimensional PEMFC model considering the effects of accumulated water film in CCL on oxygen diffusion. Two CCL microstructures were numerically generated based on agglomerate models to examine the experimental results obtained for two membrane electrode assembly (MEA) samples with different CCL porosity. The effective diffusivity of oxygen in the CCL was estimated by performing auxiliary simulations of oxygen concentration in CCL microstructures covered by a film of liquid water, with exponential correlation obtained between effective diffusivity and the thickness of the above film. Polarization curves predicted by the present model were in good agreement with experimental results. In agreement with the results of Yim et al., the present model predicts that the MEA featuring a CCL with smaller pores (which are more easily filled by liquid water) should exhibit a larger concentration loss at high current densities.     

基于Spark+YARN的空气污染预报云平台设计

近年来我国空气污染导致的雾霾天气频繁发生,空气污染已经成为一个亟待解决的重要问题,其数值预报推广应用是一个难题,主要表现在数值预报系统的运行过程中计算量大,数据量大,在传统高性能计算集群中进行空气污染预报存在资源有限、复杂的并行化操作、批处理作业等待耗时等问题,尤其对于资源缺乏的研究团队,还存在基础设施昂贵而无法负担的问题。因此,如何利用有限的资源,为大气科学家提供一种基于云计算模式的高性能计算环境,提供可扩展、快速、廉价和动态可分配的计算和存储资源,是亟待解决的关键问题。研究一种基于Spark+YARN的空气污染数值预报的云平台,针对空气污染数值预报特点,为大气科学家提供一种空气污染数值预报大数据解决方案。     

浮式竹格栅坝水力特性试验研究

在用于河道整治的建筑物中，浮式格栅坝是其中的一种，它具有结构简单，施工方便，造价低廉等诸多优点，通过直接影响格栅坝下游流速场变化的坝体透水系数ａ、坝体倾角θ、河道水深ｈ、减速率ψ等重要水力参数的试验研究；提供了在不同坝体透水程度、河道平均流速及水深、坝体倾角运行工况下的图表，为格栅坝的设计及运行管理提供了可靠的依据。     

高分子钯催化剂在不同pH介质中的催化加氢行为

报道了二种高分子钯催化剂:HPMS·Pd,PVP·Pd和Si-NH_2·Pd在不同pH介质中的催化加氢行为.实验结果表明,它们的催化加氢活性不仅与反应介质的pH值有关,而且对于不同底物的最佳pH值不同.     

Reversible Photoinduced Phase Segregation and Origin of Long Carrier Lifetime in Mixed‐Halide Perovskite Films

Mixed‐halide hybrid perovskite semiconductors have attracted tremendous attention as a promising candidate for efficient photovoltaic and light‐emitting devices. However, these perovskite materials may undergo phase segregation under light illumination, thus affecting their optoelectronic properties. Here, photoexcitation induced phase segregation in triple‐cation mixed‐halide perovskite films that yields to red‐shift in the photoluminescence response is reported. It is demonstrated that photoexcitation induced halide migration leads to the formation of smaller bandgap iodide‐rich and larger bandgap bromide‐rich domains in the perovskite film, where the phase segregation rate is found to follow the excitation power‐density as a power law. Results confirm that charge carrier lifetime increases due to the trapping of photoexcited carriers in the segregated smaller bandgap iodide‐rich domains. Interestingly, these photoinduced changes are fully reversible and thermally activated when the excitation power is turned off. A significant difference in activation energies for halide ion migration is observed during phase segregation and recovery process. Additionally, the emission linewidth broadening is investigated as a function of temperature which is governed by the exciton–optical phonon coupling. The mechanism of photoinduced phase segregation is interpreted based on exciton–phonon coupling strength in both mixed and demixed (segregated) states of perovskite films.     

基于CMX469A的FFSK调制解调器设计与应用

提出一种用STC12C5410单片机控制CMX469A集成芯片实现FFSK调制解调器的设计方法,并应用于点对点的数据传输系统。结果表明：FFSK调制解调器具有相位连续、包络恒定的特征,频带利用率优于一般FSK和PSK／DPSK。