基于LabVIEW的锅炉温度过程控制系统仿真

以经典PID控制算法为理论基础,Lab VIEW为开发平台,实现了锅炉温度控制系统的动态仿真,重点说明了增量式PID控制算法的具体实现方法。该系统能取代传统仪器用于验证PID控制规律的控制特点,完成锅炉温度控制系统的参数整定与调试,节省了硬件投资,具有推广应用价值。     

电站锅炉先进控制系统的开发与应用

为加快先进控制技术的应用,针对电站锅炉工况复杂、强耦合及大滞后等特点,采用阶梯式广义预测控制算法实现回路的先进控制,开发了一套电站锅炉先进控制系统并在电站锅炉汽水系统和风烟系统中成功应用.该系统通过OPC接口与DCS系统进行数据交换,具有较高的安全性和可移植性.     

乙烯装置急冷系统pH值的自适应控制技术

针对乙烯装置急冷系统中p H值控制系统具有非线性、大滞后、耦合及强干扰等特点,提出了基于自适应PID算法和参数自适应算法的p H值在线控制系统,并设计了p H值控制策略,开发了专用算法模块,实现了加药注入量的有效控制。试验应用表明,急冷水p H值、工艺水p H值和稀释蒸汽p H值的控制偏差均在目标值±0.5范围内。     

燃气电站锅炉先进控制系统设计与实现

某燃气电站锅炉原采用DCS控制,然而常规PID控制效果并不理想。采用广义预测控制和自适应模糊控制实现了有关回路的先进控制,构建了一套燃气电站锅炉先进控制系统,并应用于燃烧系统和汽水系统。现场应用结果表明:该先进控制系统效果良好,有关回路控制品质改善明显。     

锅炉燃烧系统智能控制策略及其在MCGS中的实现方法

在研究燃煤锅炉控制特点的基础上提出一种智能化的锅炉主蒸汽压力串级控制系统,介绍一种将模糊自适应控制器开发成组件加入到MCGS组态环境中实现对蒸汽压力的先进控制的方法。实际使用证明该方案比传统的PID串级控制系统具有更好的品质,取得了较高的经济、社会效益。     

TA浆料浓度模型预测控制

分析PTA装置精制工段TA浆料浓度配置单元的系统特性 ,讨论原控制方案中PID控制的不足 ,针对打浆水、喷淋水以及某些未知扰动对浆料浓度的影响 ,采用模型预测控制技术并记录为实施模型预测控制而进行的相关测试数据。     

串级控制及串级比值控制在硝酸等装置的应用

结合具体案例对串级控制系统及串级比值控制系统做了介绍,分别以硝酸铵装置中反应器闪蒸槽液位与进管式反应器与参反应的液氨流量之间的串级控制系统及硝酸装置氨氧化反应中氧化炉温度与氨空比的串级比值控制系统为例进行了分析。通过以上分析可以看出采用串级控制更有利于被控变量的稳定。     

模型预测控制在MACS_V6.51_DCS中的应用

实例给出MACS_V6.51_DCS系统运用模型预测控制技术进行稳定控制的新颖解决方案,解决了工业控制系统中涉及的用模型预测控制技术替代常规PID控制方法的技术要点。     

锅炉液位PID控制系统的设计

以Rockwell实验室的过程控制实验装置为实验平台,使用Rockwell公司的MicroLogix1500可编程控制器及其梯形图开发软件RSLogix500对锅炉液位控制系统进行控制,完成了锅炉液位PID控制系统的设计.并说明了锅炉液位控制系统的设计的过程和方法及其中的技术要点.     

乙烯装置急冷系统pH值先进控制应用

介绍了美国博软公司CyboCon先进控制软件在乙烯装置急冷pH值控制系统中的应用。主要分析了急冷系统中pH值的变化规律、控制特点,以及无模型控制技术在实际生产装置中应用的优点。该先进过程控制技术能够应用于具有大滞后、非线性等特点的复杂系统中,实现稳定生产、降低能耗、延长设备使用寿命、提高经济效益的目的。     

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.     

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.     

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。     

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.     

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.