冷中间包衬对铸坯皮下气泡的影响

对铸坯产生皮下气泡的原因进行了调查和分析。认为中间包绝热板村中的有机挥发物和残余水分是铸坯产生皮下气泡的主要原因。从中间包绝热板的配方、制造技术和装砌等方面采取改进措施，可有效减少铸坯皮下气泡。     

Adaptive tracking control of leader–follower systems with unknown dynamics and partial measurements

In this paper, a decentralized adaptive tracking control is developed for a second-order leader–follower system with unknown dynamics and relative position measurements. Linearly parameterized models are used to describe the unknown dynamics of a self-active leader and all followers. A new distributed system is obtained by using the relative position and velocity measurements as the state variables. By only using the relative position measurements, a dynamic output–feedback tracking control together with decentralized adaptive laws is designed for each follower. At the same time, the stability of the tracking error system and the parameter convergence are analyzed with the help of a common Lyapunov function method. Some simulation results are presented to validate the proposed adaptive tracking control.     

A new core–shell type fluorinated acrylic and siliconated polyurethane hybrid emulsion

A novel core–shell type fluorinated acrylic and siliconated polyurethane (FSiPUA) hybrid emulsion was prepared by seeded emulsion polymerization using siliconated polyurethane (SiPU) as a seed and forming the structure with SiPU as a shell and the copolymer of butyl acrylate (BA) with 2,2,2-trifluoroethylmethacrylate (TFEMA) as a core. SiPU was synthesized using isophorone diisocyanate (IPDI), polytetramethylene ether glycol (PTMG), polypropylene glycol (PPG), dihydroxybutyl-terminated polydimethylsiloxane (PDMS), dimethylol propionic acid (DMPA), 1,6-hexanediol (HDO) and triethylamine (TEA). The contents of siloxane and fluorine were determined according to the feed ratio. Fourier transform infrared spectroscopy (FTIR) was used to identify the chain structure of SiPU and FSiPUA. Investigation of transmission electron microscopy (TEM) confirmed the core–shell structure of FSiPUA emulsion and gave the particle size at about 50 nm. The measurement results of water contact angles and the solvent absorptions in water and n-octane for cured films showed that the water and the oil repellency for FSiPUA had been improved significantly with a suitable content of fluorine and siloxane.     

脉冲式气流干燥器的模拟与结构优化

针对脉冲式气流干燥器,在以能耗最低为主目标函数的操作优化数学模型的基础上,加入了加速段高度、减速段高度及管径比等参数,建立了结构优化数学模型,以干燥每千克水为主目标函数编制了模型寻优程序,计算得出了物料终湿含量要求范围内的最佳结构参数.     

扎实推进规划工作 培植绿色发展理念——湖北省中小河流水能资源开发规划工作情况介绍

本文介绍了湖北省中小河流水能资源开发规划工作进展,规划工作在树立绿色发展理念、摸清水能资源开发状况等方面取得的成效,以及湖北省为推动规划工作采取的主要做法。     

浅谈脱硫液中PDS质量浓度测定方法

提出了在以PDS催化剂作为单一的脱硫催化剂时,脱硫循环液中贫富液的PDS质量浓度的测定方法,可有效地指导在脱硫工序投加PDS的操作及生产运行,为确保出脱硫工序煤气中H2S含量稳定控制在20mg/L以内奠定了基础。     

密度泛函方法的ZSM-5分子筛上苯与乙烯烷基化反应机理研究

采用密度泛函(DFT)方法对于ZSM-5分子筛上苯与乙烯的烷基化反应机理进行研究。选取了包含酸性质子的8T原子簇模型代表ZSM-5分子筛的部分结构。采用B3LYP/6-31G(d)水平从生成能与反应活化能角度对于烷基化反应发生时可能存在的2种联合机理和一种分步机理进行了计算与比较。结果表明,联合反应机理中乙烯的质子化和C-C键的形成同时发生,而分步机理开始于乙醇盐中间体的生成,随后与苯反应生成反应产物。分步机理中乙醇盐中间体生成步骤的活化能(124.55 kJ/mol)低于联合机理的反应活化能(168.98 kJ/mol和156.06 kJ/mol),而烷基化步骤的活化能(209.35 kJ/mol)高于联合机理的反应活化能,由此可以推断ZSM-5分子筛上苯与乙烯的烷基化反应时2种机理同时发生,存在竞争关系。     

Competitive Reaction During Decomposition of Hexachlorobenzene Over Ultrafine Ca–Fe Composite Oxide Catalyst

The decomposition of hexachlorobenzene (HCB) has been investigated over ultrafine Ca–Fe composite oxide catalyst (Ca/Fe atomic ratio was 3.4), CaO and α-Fe₂O₃ by using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Adsorption experiments on the surface of oxides monitored by in situ DRIFTS showed that partial oxidation products, i.e., phenolate and acetate species were formed on the surface of Ca–Fe composite oxide. The further studies indicated that Ca–Fe composite oxide catalyst was easier to induce the rupture of C–Cl bond and C–C bond of aromatic rings. The best catalytic activity of Ca–Fe composite oxide may be related to the acidity, which was determined by NH₃–TPD. The products after reaction have been analyzed by XRD and chloride selective electrode. Ca–Fe composite oxide exhibited the highest extent of mineralization for organic chlorine among the different oxides tested. The combined results of current and previous experiments demonstrated that two competitive reactions took place during the decomposition process of HCB: (1) hydrodechlorination resulting in the formation of lower chlorinated benzenes and (2) oxidation of aromatic rings leading to the rupture of aromaticity and the formation of oxidation products. The latter is the major process in the coexisted competitive reaction. A possible decomposition pathway was discussed.     

存在飞轮安装偏差与故障的卫星姿态容错控制

基于滑模控制理论提出一种刚体卫星姿态稳定控制方法,实现对反作用飞轮部分失效故障的容错控制,以及对其安装偏差的补偿控制,并从理论上证明了所设计的控制器在有限时间内能够实现对闭环姿态控制系统的几乎全局渐近稳定控制.最后将所设计的控制器应用于某型卫星姿态稳定任务,仿真结果验证了所提出方法的有效性.     

利用OpenSSL实现PKI中数字签名及数字验证的研究

主要介绍如何利用OpenSSL实现数字签名及数字验证,重点关注数字签名及数字验证的处理流程。通过对比实验,得到数字签名方案中的几个特点,并着重分析算法和公钥算法对数字签名方案效率的影响,为完善数字签名在实际通信安全领域中的应用提供建议。