压力容器密封结构介绍

介绍了压力容器用法兰连接密封、螺纹密封、填料密封、金属平垫密封、金属环密封、双锥密封、隔膜密封和Ω环密封的结构特点与使用范围,并对密封处发生泄漏的原因进行了分析总结。     

静密封新技术及应用

静密封管理是化工生产设备管理的重要内容。提高垫片密封的可靠性,要加强密封机理、密封垫片新材料的研究,探索科学的密封设计方法,积极采用密封预紧新方法、新工艺,提高密封的密封能力。     

高压酚水泵轴密封问题及改进

分析了高压酚水泵轴密封发生泄漏的原因。总结了高压酚水泵轴密封由机械密封改成填料密封，又由填料密封改定制机械密封，再改成集装式机械密封的技改过程。     

机械密封技术与研发方向

介绍了目前先进的机械密封应用技术主要有密封端面改形技术、控制平衡比密封技术、组合密封技术、窄环刃边密封技术和可控机械密封技术.指出了机械密封的研究开发方向:一是基础理论进一步纵深发展,二是对机械密封失效分析研究,以及对纳米材料机械密封的开发与应用.     

造粒机辊轮密封系统的改造

分析了密封结构、工作介质腐蚀性、粉体静压力对造粒机辊轮组合密封的影响,讨论了组合密封中迷宫密封与唇形密封的失效原因,给出了迷宫密封结构和密封方向的改进方案、唇形密封装配的方法及环形压紧弹簧材料的改造措施,以及静轴的防腐措施及其加工要求。     

离心压缩机轴封的发展和使用现状分析

以石化工艺气离心式压缩机的轴端密封为研究对象,根据各个阶段使用的轴端密封形式及其使用情况,分别介绍了传统迷宫密封、浮环密封、油膜螺旋槽机械密封和干气密封的结构,分析它们的各自技术特点,指出其中存在的不足之处和改进方向,并对膜螺旋槽端面机械密封和干气密封的技术特点和优势进行了重说说明,指出现在轴端密封的发展方向是干气密封。     

硅酮胶密封的中空玻璃

中空玻璃的边缘密封系统的主要功能是将两片或多片玻璃结构性黏结起来防止水汽进入.通过双重边缘密封系统可以取得最好的密封效果,在该系统中,第一道密封是由聚异丁烯基密封胶提供水汽密封,第二道弹性密封则确保中空玻璃在相应荷载下的结构整体性.硅酮双重密封的中空玻璃比有机胶密封的中空玻璃具有较低的水汽渗透率,因为边缘密封的渗透性几乎完全由第一道密封(PIB)的渗透性决定,并且因为硅酮第二道密封在阻止水汽扩散进入第一道密封方面比有机胶表现得更好.     

动密封技术在纯碱厂气体密封中的应用

介绍了动密封技术的分类及基本原理，论述了接触式密封、非接触式密封、组合式密封等动密封技术在纯碱生产中关于气体密封的应用，并提出了相应的注意事项。     

一种新型蜂窝密封的封严特性

为提高蜂窝密封的封严特性,改善转动机械的工作效率,本文在传统蜂窝密封基础上通过改变蜂窝的排列方式得到了一种新型蜂窝密封。采用ANSYS CFX软件对新型蜂窝密封和传统蜂窝密封内的三维流动情况进行了数值模拟,并引入泄漏系数,对这两种蜂窝密封在密封间隙、芯格直径、芯格深度、蜂窝壁厚、压比和转速变化时的封严特性进行了对比分析。结果表明：新型蜂窝密封在大压比、薄壁厚和小间隙下比传统蜂窝密封更具封严优势;当蜂窝密封的芯格直径为3.2mm时,新型蜂窝密封比传统蜂窝密封的泄漏系数减少了7.1%;改变蜂窝芯格深度,新型蜂窝密封的封严特性优于传统蜂窝密封。特别是当转速增加时,新型蜂窝密封内的周向漩涡更稳定,能量耗散更强,泄漏系数更小,密封效果更好。     

隔膜密封换热器的结构及计算

对隔膜密封换热器与螺纹锁紧环换热器进行了对比,介绍了换热器的结构组成及密封原理,它的密封结构类似于金属平垫密封,属于强制密封。它是通过密封盘、压盖及大螺栓来实现密封。还介绍了换热器主要零部件的计算。     

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.     

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。     

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.