可编程脉冲产生器的设计及应用

文中针对脉冲产生器的市场供应与实际应用情况,给出了一种以单片机为CPU核心的可编程脉冲产生器的设计思路,阐述了完成该产生器的硬件结构和软件设计方法,并给出相应的硬件电路和软件设计流程;为了验证设计的合理性,将其应用于某测控系统的步进电机控制器中,并进行实验测试,结果表明该设计具有低成本、高可靠性等特点,特别是其脉冲宽度与周期可编程预置,不仅增加了设备的使用灵活性,而且扩大了应用范围,可推广应用于多种功能的测控系统中。     

基于互触发的Oracle细粒度数据保护和恢复的研究及实现

本系统的主要思路是利用Oracle的触发器、Flash Recovery Area等技术,结合J2EE技术,实现一套基于B/S架构的Oracle数据保护和恢复系统,包括权限管理、数据恢复、系统管理三大模块,旨在解决以下问题:(1)建立新的权限控制。Oracle自带的权限控制不够安全,本系统拟创建一套新的权限体系,作为对Oracle的权限的补充,使业务系统的数据使用起来更加安全;(2)建立新的数据恢复。用软件实现Oracle的数据实时恢复,在真正执行危险操作以后,对数据进行针对性地、迅速恢复;(3)实现互触发保护,避免"通过人为的方式直接去drop触发器"之类操作的实现。     

一种新的修正恒模算法

阐述了恒模算法(CMA)、修正恒模算法(MCMA)和判决引导(DD)算法的基本原理。针对CMA和MCMA收敛速度慢,固定步长条件下收敛速度和剩余误差之间存在矛盾的缺陷,在分析CMA误差特性的基础上,利用DD算法误差函数的模值和判决器输出构造新的误差函数,提出了一种新的变步长MCMA。新算法在加快收敛速度的同时保持小的剩余误差。仿真结果表明,新算法比CMA和MCMA收敛速度快,均衡输出剩余码间干扰(ISI)小而且能克服相位偏移,具有很好的实用性。     

一种面向SOA业务恢复的服务选择算法

针对SOA业务恢复的服务选择问题,本文提出了一种QoS近似全局最优的服务选择算法GALSA:首先利用GA算法将全局QoS约束分解为最优的局部QoS约束,然后利用LSA算法选取出满足局部QoS约束的最优服务。算法不仅能作用于服务重构的服务选择过程中,而且在单个服务节点失效时亦能选取出满足全局QoS约束的服务进行替换。理论分析与实验结果说明了算法的可行性和有效性。     

计算机硬盘坏磁道修复的思路与技巧

本文通过隐藏坏磁道分区的方法,着重介绍了硬盘坏磁道的修复技术及注意事项,同时还介绍了逻辑坏磁道、0磁道损坏的修复方法。     

Nanocomposites of CsPbBr3 perovskite quantum dots embedded in Gd2O3:Eu3+ hollow spheres for LEDs application

Gd₂O₃:Eu³⁺@CsPbBr₃ quantum dots (QDs) mesoporous hollow nanocomposites with good luminescent properties and high stability were built. Among which, the hollow Gd₂O₃:Eu³⁺ spheres and CsPbBr₃ QDs were prepared by urea homogeneous precipitation and hot-injection method, respectively. Finally, the Gd₂O₃:Eu³⁺@CsPbBr₃ QDs shell–core compounds were constructed through mechanical stirring. The structure, morphology, stability and luminescent properties were studied by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry/thermogravity (DSC/TG), X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), photoluminescence excitation/photoluminescence (PLE/PL) and life decay tools. Compared to the original CsPbBr₃ QDs, Gd₂O₃:Eu³⁺@CsPbBr₃ QDs display better photostability, thermal stability and current stability. The resulting Gd₂O₃:Eu³⁺@CsPbBr₃ QDs composite exhibits good yellow emission. The Gd₂O₃:Eu³⁺@CsPbBr₃ QDs mixed silicone resin was directly coated on the blue LED chip, then the w-LED device with the color coordinate of (0.31, 0.32) was successfully assembled. The Gd₂O₃:Eu³⁺@CsPbBr₃ QDs compounds with excellent luminescent properties and stability are expected to be widely used in lighting and display areas.     

含钼废渣冶炼钼铁的优化试验

利用含钼废料钼酸钙为原料,采用碳还原法冶炼钼铁,通过单因素分析试验及正交试验优化得出最佳的试验条件,钼酸钙加入量应低于10%,熔炼温度为1 525 ℃,保温时间为25 min,碱度为1.3。通过XRD、SEM、EDS分析得出用此方法生产得到的钼铁合金中,钼以Mo₂C、Fe₃Mo以及Fe₃Mo₃C的形式存在,渣系为二元玻璃渣系,具有与普通玻璃相似的成分系统。经测定合金中钼的回收率大于99%,钼资源回收效益可观。     

PRO/Ⅱ软件在硫磺回收中的二次开发应用

硫磺回收装置的设备需要有较大的操作弹性。针对其过程气进口压力低，手工计算难于进行严格的全程压降计算，现以PRO／Ⅱ软件为开发平台，通过扩充数据库和建立模拟流程，成功地将其用于硫磺回收装置的设备选型和核算，为工程设计提供了先进的计算手段。     

Simultaneous recovery of copper and surfactant by an electrolytic process from synthetic solution prepared to simulate a concentrate waste stream of a micellar-enhanced ultrafiltration process

Electroplating method was employed to recover copper and surfactant simultaneously from synthetic solutions prepared to simulate concentrated waste stream generated from micellar-enhanced ultrafiltration. Effects of surfactant and copper (II) concentrations, surfactant to copper (II) molar ratio (S/M), electroplating voltage and time, solution pH, and ionic strength on metal recovery and electrical current efficiency were investigated. Results show that at a fixed S/M ratio of 5, the first-order kinetic constant for Cu (II) removal by electroplating increases with decreasing SDS concentration. At fixed SDS concentration of 8.5 mM, increasing initial Cu (II) concentration increases both Cu (II) recovery and current efficiency. Electrolyte pH has profound effects on the metal recovery and current efficiency due to the difference in solution conductivity after pH adjustment and the extent of Cu (II) adsorption onto SDS at different pHs.     

一步法生产涤纶FDY工艺的探讨

利用ＫＶ７３１纺丝设备一步法生产出涤纶ＦＤＹ，探讨了热辊拉伸和熔体温度对纤维质量的影响。采用高特性粘数的聚酯切片，严格控制纺丝工艺，可以在５０００ｍ／ｍｉｎ的纺丝速度下纺制高质量的细旦涤纶ＦＤＹ。