锦纶聚合釜温度模糊自适应PID控制系统研究与仿真

锦纶聚合釜温度具有非线性、大滞后等特点,使用传统PID控制器的控制效果不够理想。在建立聚合釜温度数学模型的基础上,采用模糊算法与PID控制相结合的模糊自适应PID控制算法,实现PID参数自整定,提高控制精度。基于MATLAB平台构建釜温控制系统模型,仿真结果表明所提模糊自适应PID控制算法效果优于传统PID控制。     

工业电炉温度控制系统中数字PID算法的改进研究

简单分析了工业电炉温度的控制系统和简单原理,利用基础PID控制算法控制温度效果,发现缺陷,分析原因,提出一种改进PID算法。最后证明改进PID算法控制效果优于常规PID控制。     

基于PID的锅炉温度控制系统设计

为了解决锅炉温度过高或者过低造成的危害,本文设计了一款基于PID的锅炉温度控制系统。系统通过实时采集锅炉温度信息,并结合Labview所做的界面上加热阻丝的颜色变化来判断锅炉加热的快慢,再通过PID控制器调整锅炉温度变化快慢来控制温度大小。通过实验可以平稳的控制温度变化。     

甲醇精馏塔温控系统滑模变结构控制仿真

针对甲醇精馏塔具有非线性、大时滞,数学模型难以准确描述的特点,设计了一种滑模变结构控制算法的温度控制系统。该系统通过对不断测量的实际温度值与目标温度值进行比较,利用滑模变结构控制算法对实际温度进行控制调节。采用Matlab软件中的Simulink平台实现温度控制系统的仿真。并且利用GUI界面设计,通过设定不同温度值进行比较。实验结果表明:在误差允许范围内,滑模变结构实时温度控制明显优于传统PID控制。     

基于PLC与力控组态软件实现的温度控制系统

本文以锅炉温度控制系统为例,介绍了PLC与力控组态软件在温度控制系统中的应用与实现方法。讨论了FX2N系列PLC的PID指令在温度控制过程中的应用,并介绍了力控组态软件在锅炉温度控制系统的监控层的组态方法与实现。     

火电厂锅炉水质调节加药系统的自动控制

火电厂凝结水、给水和锅炉水的加药处理，是重要的水质调节措施。实施加药自动控制，是实现水质调节实时性和准确性的有效手段。在自动加药控制系统中，由于被控对象存在时滞大、负荷变化大和扰动大的特征。常规PID控制达不到满意的控制效果。文章应用改进的PID控制算法，实现了系统控制的良好稳定性、鲁棒性和控制品质，现场应用控制效果满意。     

循环流化床锅炉给水与出口过热蒸汽减温水流量分配自动控制系统改进

由于循环流化床锅炉工艺的特殊性，原锅炉水位自控系统和出口过热蒸汽温度自控系统之间有关联影响，为使控制最佳效果，在原控制系统基础理上增加了一套PID调节系统，使汽包水位和出口过热蒸汽温度能够独立控制，且都可维持在给定值上，即实现了两系统的解耦控制。     

FUZZY-PID控制系统在工业窑炉控制中的应用

结合FUZZY控制技术和PID控制算法的优点设计了FUZZY-PID控制系统,对陶瓷工业窑炉的温度进行控制。仿真结果表明,该控制系统提高了控制精度和减小超调量及静态误差,缩短了调整过程时间。     

转矩流变仪温度控制系统的设计

介绍了转矩流变仪的温度控制系统的硬件设计和软件设计,采用改进型的PID控制算法与积分分离的数字PID控制算法配合的单片机温度控制方法,使系统具有良好的动态响应特性,几乎没有超调量.经实际调试,得到了良好的控制效果.     

基于PLC的专家PID控制算法在精密压药液压机控制系统中的应用

为了使精密压药液压机控制系统的性能满足军工炸药压制工艺的要求,提出了一种基于PLC的专家PID控制算法。给出系统的控制原理,并将增量式PID控制算法与专家控制器结合通过PLC实现对系统压力的控制。常规PID算法和专家PID算法在实际运行中的结果表明:基于专家PID控制算法的系统压力控制精度高、响应速度快、超调小、抗扰动性能强、鲁棒性好。     

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。