浅述变频系统的改造

阐述了原有动变频系统存在的不足及改为静变频系统的必要性、静变频器及主要电气设备的选择计算、以及静变频系统的优点。     

涤纶纺丝变频传动和控制系统

介绍80位涤纶纺丝机的变频调速系统,采用PC机和PLC控制变频器,1台变频器单独驱动1台计量泵电机,16用1备的切换方式,此系统线路简单明析,操作维修方便,控制平稳可靠。并对该系统的常见故障进行了处理。     

10MW级高压变频器在600MW机组给水系统中的应用

本文针对600MW机组锅炉给水系统,应用国产10MW级高压超大功率变频器代替液力耦合器机械调速,提高给水泵系统机械效率、节能降耗的经验进行了积极探讨。通过实践证明：在既有液力耦合器调速的基础上,通过高压变频器应用仍可以取得良好的节能收益。     

交流变频调速器在恒压变量供水控制系统中的应用

介绍利用PLC和交流变频器 (VVVF)实现恒压供水的工作原理 ,论述了用 1台变频器控制 3台异步电机的工作过程 ,使系统达到自动跟踪 ,稳定恒压 ,变量供水     

注水变频技术研究与应用

文章介绍了以TD2000变频器为核心开发的一种注水系统控制技术的应用,对推广应用变频技术有一定参考作用.     

变频调速与串级调速在窑尾风机上的应用比较

我厂窑系统煅烧无烟煤的改造中,其中一项是将窑尾风机原有的串级调速控制系统更换成变频调速系统。改造后,变频器和电动机曾一度故障频繁,既有电动机改压缺陷问题也有变频器设定问题,严重影响生产,曾一度动摇厂方继续使用变频器的信心。是否要换回原来的串级调速系统,成为当时电气技术人员必须尽快解决的问题。     

变频调速系统在粘胶液位控制上的应用

阐述了变频调速液位控制系统的组成、控制原理、变频器的选择、装配，以及变频调速系统的特点。     

高压变频器在化工装置中的应用

本文着重介绍高压变频调速系统在某化工厂丙烯酸装置循环水泵使用维护情况,并讲述了变频器在实际操作中注意事项、操作方法、故障处理、维护方法等。     

刍议变频器谐波干扰的形成及对策

主要介绍了变频器谐波干扰形成的机理、干扰传播的途径,初步讨论了谐干扰的危害,在此基础上提出了谐波抑制和治理的有效措施。随着我国经济的发展和科技的进步,对变频器的使用越来越广泛,因此重视变频器的EMC要求,以适应更广泛的工业现场环境,提高系统的工作可靠性已经成为变频调速系统在实际应用中的一个关键问题。     

变频器在PET装置中的应用

介绍了变频器在PET装置中的应用。简述了变频器的工作原理及特点,详述了变频器应用在PET装置中的控制方案及其注意事项,变频器应用到PET装置中起到了较好的节能及控制效果。     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

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.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009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、环氧树脂、不饱和聚酯树脂)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。     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。