热套式超高压容器的设计及有限元分析

设计了工作压力为600 MPa、容量为200 L的超高压容器筒体,并利用有限元软件ANSYS对其进行分析,得到了筒体在预应力和实际工作两种状态下的应力分布结果。经优化取得了内外筒体的最佳过盈量及界面半径,使得各层筒体的应力分布基本均匀。     

热套圆筒最佳过盈量和自增强压力简捷计算

介绍了自增强双层热套容器在操作时内外筒体应力既满足等强度设计要求,又满足筒体最大当量应力水平为最低的优化设计条件的简捷计算方法,及其最佳过盈量和最佳自增强压力的理论解。通过对实例的计算对比,说明该方法适用于工程设计计算。     

压缩机叶轮强度设计

介绍了叶轮过盈量和材料对其强度的影响,通过对叶轮过盈量和应力计算以及应力分布云图分析后对叶轮进行了调整。通过叶轮应用分布云图分析,结构调整后的叶轮强度和过盈量满足使用要求。     

基于ANSYS的立式厚壁压力容器应力分析

应用ANSYS软件分析了立式厚壁压力容器工作时筒体与封头的应力分布。结果表明:最大等效应力处于在筒体的内壁区域;等效应力从筒体或封头内壁到筒体或封头外壁呈近乎线性下降。筒体与封头的连接处附近外壁和内壁的等效应力变化最大。     

带加强箍离心机转鼓应力的有限元分析

用有限元法对具有不同过盈量的加强箍对离心机转鼓内应力的影响进行了分析比较。结果表明有过盈量的加强箍不仅为转鼓筒体承担部分载荷,而且因过盈在转鼓内产生预应力,在工作条件下可大幅度降低转鼓内的应力;对离心机转鼓合理设置加强箍、选择加强箍与筒体间的过盈量具有参考价值。     

热套压力容器半径过盈量的优化设计

根据热套压力容器内外筒应同时达到屈服的等强度设计原则,推导出最佳半径过盈量的解析方程,利用C程序计算出高精度的最佳半径过盈量,并运用ANSYS软件对热套压力容器进行了应力和变形分析。     

半可燃药筒竖放状态下的应力应变与结构强度分析

针对半可燃药筒在竖向放置过程中可能出现的受力变形问题,建立了力学模型.采用三维非线性有限元理论对药筒的接触变形进行了计算,得到了药筒的应变、应力分布规律和半可燃药筒结构强度的数值预测.结果表明,在竖放无载荷的情况下,筒体在变直径区域产生应力集中,与金属底座的交界处应力最大.半可燃药筒的筒体变形量较大,金属底座各处的变形量几乎为零.筒体与金属底座上的最大应力远小于材料的许用应力,因此筒体结构和金属底座是安全的.     

W形筒体外置蜂窝夹套应力分析与结构优化设计

采用ANSYS有限元方法对W形筒体的U形蜂窝夹套进行弹性应力分析与强度校核,获得夹套结构的应力分布和位移分布。在满足强度要求和稳定性要求的前提下,采用ANSYS结构优化设计方法对蜂窝短管夹套的内壁厚度、夹套厚度、短管直径与短管壁厚4个参数进行了优化设计计算,使得蜂窝短管夹套的总质量下降了41.2%。     

应用SAP5程序进行间歇式球磨机筒体的强度分析

一、前言本文应用SAP5程序进行对间歇式球磨机筒体强度分析,既能处理厚壁园筒理论问题,也能解决薄壁园筒计算问题;使筒体强度分析更具有普遍意义,便于广泛采用.当前已采用均布载荷筒支梁方法计算,缺乏空间状态的位移和应力分布,且只计算静态,没有动态状况下的分析,失之偏颇而不全面.应用本方法可获得筒体的环向和径向的空间位移变形,以及静态,动态状况下的环向     

大型回转窑筒体力学状态综合分析

利用有限元法计算回转窑筒体应力的分布状况。以中铝集团河南氧化铝厂3号窑为例,将筒体、衬砖及窑皮作为一个系统来研究,将筒体和衬砖分层分段建模,综合考虑了筒体、衬砖轴向的材质、厚度变化等因素,最终数值模拟了该窑筒体的应力分布状态。     

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。     

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.     

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.