分流式降液管的流体力学性能研究

用分流式降液管以空气和水进行了塔盘冷模实验,研究了板压降、板上清液层高度和泡沫层高度、降液管泡沫层高度等流体力学性能,并在相同条件下与无分流式降液管进行了对比实验。结果表明:在相同的操作条件下,分流式降液管的塔板压降比无分流式降液管的塔板压降平均降低了39.3%,分流式降液管能有效降低塔板的溢流强度,提高了塔板的处理量。     

高通量塔板悬挂式降液管击穿漏气的气液相研究

采用空气-水物系,在直径为500mm的有机玻璃塔中对底部分别开有8个和12个液流孔的悬挂式降液管的漏气进行了研究,并在假设漏入降液管的气体产生的压降与板压降相等的基础上建立了击穿漏气模型.结果表明,当塔内的气体流量逐渐增大,漏入的气体以气柱的形式连续进入降液管时,降液管液层被击穿,降液管无法正常操作.根据实验数据得到了击穿漏气模型的关联式,关联式的计算值与实验值吻合较好.开有12个液流孔的降液管在液流孔的真实漏气气速为1.40 m/s时,漏入的气体会击穿降液管液层.     

多降液管筛板萃取塔内流动特性和塔效率的研究

选择正丁醇－丁二酸－水作为实验体系，以有机相为分散相，在φ１００ｍｍ的塔内系统地研究了单降液管、双降液管和三降液管三种塔板的两相流动特性和传质效率，并对其进行了比较。研究结果表明，在相同的操作条件下，多降液管大孔筛板塔比单降液管塔内的动态存留分数大，板下静液层高度小的特点，同时多降液管筛板塔比单降液管筛板塔具有更高的塔效率。     

板式塔降液管操作能力研究

在φ600mm的透明有机玻璃塔中,采用易发泡物系,在相同操作条件下,通过测量了CTST塔板和F1型浮阀塔板降液管中液体的RTD曲线和泡沫高度,对两种塔板的降液管操作能力进行了比较研究.实验结果显示CTST比较浮阀塔板,其降液管操作能力大许多.     

悬挂式降液管自液封线的实验研究

悬挂式降液管塔板经历了四十多年的发展。由于这类塔板的降液管悬挂于塔板下的气相空间,气体可能会从降液管底部液流孔漏入降液管,故要求悬挂式降液管能自液封。以往徐崇嗣提出的自封线以降液管几乎不漏气作为自封点。作者提出以降液管每秒漏气一次作为新的自封点标准,该标准使漏气分率小于0.1%。测定自封线的实验在300mm×200mm的有机玻璃塔中进行,物系为空气-水。实验还采用多路电导测试仪,测量了原自封线和本实验自封线在液流孔处漏气所占的时间分率。实验结果表明,新自封线适用于中等和大液气比工况,它优于原自封线,能更客观地反映悬挂式降液管的自封性能,扩大了塔板的稳定操作区。     

分散降液筛板塔传质性能

在筛板塔的基础上,研发了一种新型板式塔--分散降液筛板塔,将传统筛板塔的弓形降液管改为均布于塔板筛孔间的多降液管结构,使整个塔板面成为均匀降液和受液的传质区,并新增淋降和喷溅传质区,在全塔空间内实现立体、连续的微分接触式气液传质过程,另外,塔板之间可以加装填料来强化传质,或装填催化剂以促进伴随化学反应的传质过程。以“氧气-空气-水”为体系,初步研究了分散降液筛板的传质性能及其影响因素,并与传统筛板进行比较,结果表明:分散降液筛板气液分布均匀,接触充分,在同等条件下传质效率比传统筛板提高了8.4%~9.7%。     

悬挂降液管塔板的冲击漏液及其对传质效率的影响

从理论上分析了悬挂式降液管塔板上产生冲击漏液的原因，并提出在塔板的受液区安装防冲漏液装置来减小冲击漏液量。在－φ500的冷模塔内以空气－水为物系测定了冲击漏液量，在－φ300的热模内以酒精－水为特系测定了塔板效率。结果表明：没装防冲击漏液装置的悬挂工降液管塔板的冲击漏液量达总液量的7％以上，而安装防冲击漏液装置的悬挂式降液管塔塔板基本上没有冲击漏液，可以提高塔板传质效率5％以上。     

多降液管筛板塔试验报告

在“教育必须为无产阶级政治服务,必须同生产劳动相结合”的光辉思想指引下,我们接受了化肥生产技术改造的任务,对水洗塔进行技术革新。我们本着“洋为中用”的精神,把具有显著优点的多降液管筛板塔(简称 MD 筛板塔),应用于我国的生产实践。MD 筛板塔的结构已在资料作了介绍。其最大特点是塔板上设置多条降液管,相邻两板的降液管又互相垂直,而且降液管悬挂于气相空间,降液管的底部开有液流孔,这种形式     

提高悬挂式矩形降液管塔板效率的研究

分析了影响悬挂式矩形降液管塔板(DJ塔板)效率的原因,并提出在塔板的受液区安装防冲击漏液装置以及在塔板下方复合填料来提高塔板的传质效率.在一(Φ)300 mm的热模塔内,以乙醇-水为物系,全回流的情况下测定了受液区设置防冲击漏液装置以及塔板下方复合规整填料的DJ塔板的全塔效率.试验结果表明受液区设置防冲击漏液装置的DJ塔板的塔效可提高5%～10%;塔板下方复合100 mm规整填料的DJ塔板的塔效可提高15%～25%,比弓形降液管F1型浮阀塔板高5%～15%.     

碳化工段

多降液管筛板塔[以下简称M.D.塔],是最近用于小化肥厂低压水洗的一种新塔型。此塔是在塔板上设置多条降液管,相邻两塔板的降液管又互相垂直,降液管悬挂于气相空间,降液管底部开有液流孔,液流从这些液流孔降至下一块塔板。与填料塔、单溢流筛板塔比较,M.D.塔喷淋密度较大,见表Ⅳ—1。     

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.