多波形脉冲电镀电源控制系统的研究

设计了一种采用两级结构来实现工艺要求的双向脉冲电源,在此基础上设计并实现了电源的控制系统.由于电源输出波形复杂,经分析对比,提出了采用飞利浦80C552单片机对电源进行控制的总体方案,实现了输出波形的频率、幅值和占空比的连续调节以及运行参数的实时显示,便于工艺技术人员及时进行参数调节,有利于工艺探索.     

低温镀铁程序控制器

1 前言低温镀铁工艺广泛应用于机械零部件修复。低温镀铁使用的电源多为可控硅不对称交流电源。由于镀铁工艺比较复杂,需要操作人员不断调节电源输出的正向电流和反向电流,使电源输出的不对称度能够按照工艺要求的规律变化,因此操作人员劳动强度大,调节的精度差,很难保证镀层质量。我们为宁夏大武口矿山机器厂设计的低温镀铁程序控制器可以使镀铁电源的输出按照工艺要求自动变化,收到了比较明显的工艺效果,具有推广价值。     

基于 ACS2000 DFE 中压变频器的 PTA搅拌器传动系统改造

介绍了 ACS2000 DFE 中压变频器的拓扑结构、电源配置、控制系统构成、电平输出原理及直接转矩控制。阐述了在 PTA 搅拌器传动系统改造中,ACS2000 DFE 中压变频器一键自动起停、速度切换及调节、报警及故障输出、运行状态监测的参数及接线设计。通过对 ACS2000 DFE 中压变频器的外部报警及联锁设计分析,提出了外部联锁变更的参考方案。     

基于Multisim的直流稳压电源的仿真分析

介绍了稳压电源中整流电路、滤波电路和稳压电路的构成,通过Multisim软件对电路的电源参数选择、纹波系数和输出波形进行了仿真与分析．结果表明,利用该软件可以分析设计出满足不同要求的电源分配系统,降低设计复杂度,提高设计效率,缩短设计周期．     

网络设备的多路输出电源设计

针对某院计算机网络设备的电源插线板和电源适配器品种多、线路凌乱的情况。对这些电源适配器进行了测试、分析、整理,归纳出6个供电电压、3个供电电流,设计了结构合理、适用于计算机网络设备的多路输出电源。实践证明,该电源运行稳定、可靠,实际使用效果很好。     

基于模糊PID的变频技术在电镀电源改造中的应用

为了解决精密工件电镀过程中因电流波动导致的镀层不均匀的问题,在保留原电镀电源控制方式不变的基础上,完成了对其控制系统的升级改造.改造后的系统采用西门子WinCC开发人机交互界面,以PLC为控制核心,通过实时在线调整PID参数控制变频器输出合适的频率以改变电镀电源电机的转速,提高输出电流的调节精度,以满足高精度镀件产品的需求.实验证明,改造后的电源控制系统在不同负载下均能保证电流的调节品质并且具有较强的抑制扰动能力,镀层质量得到显著改善.     

SMD-300多组换向脉冲电镀电源智能化研究

研制了一种由高频开关电源做直流电源、IGBT管做斩波管、PLC(可编程序逻辑控制器)做信号控制、人机界面做操作显示、输出正反向多种波形的SMD-300多组换向脉冲电镀电源。对PLC进行了简单介绍,详细论述了该电源PLC控制系统的方案和人机界面的功能：该智能脉冲电镀电源具有200个可调节参数,对其输出的多种波形进行了讨论,并对利用该电源来制备的多层纳米级镀层提出了展望。     

高精度脉冲电镀电源控制系统设计

为满足对脉冲电镀电源控制系统提出的更高要求,兼顾高精度与数字化控制的要求,设计出一套以STM32F107芯片作为控制核心的控制系统。通过STM32F107芯片对PWM信号高精度控制及其他外部信号检测与运算,实现脉冲精确控制、电流检测与调控、对复杂负载自适应调节,提高脉冲电镀电源控制系统的控制精度与转换效率。     

不对称交直流电镀电源的研制

利用可控硅技术，研制了一种手动调节式不对称交、直流电镀电源，该电源具有输出稳定，交直流交换方便，不对称比范围广等优点；有效地于轴承、轧辊等机械零部件的修复性镀铁，电镀电源性能稳定。     

虹润NHR-6800系列彩色无纸记录仪

正NHR-6800系列彩色无纸记录仪的特点:·采用高性能ARM微处理器,具有功耗低、响应快、功能强及性价比高等特点;·7英寸进口800×480点阵TFT高亮度彩色图形液晶显示,LED背光;·输入-输出-电源之间隔离设计,对输入、输出、电源采取可靠保护和强抗干扰设计;·产品开孔尺寸138mm×138mm×76mm,76mm为插入深度;     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。