夏热冬冷地区不同墙体结构的保温层厚度分析

选择合适的保温材料及其厚度是实现建筑节能的重要途径.针对夏热冬冷地区,建立了计算保温材料经济厚度的数学模型,分析了XPS、EPS、聚氨酯泡沫、玻璃纤维棉以及气凝胶保温材料应用在页岩空心砖、加气混凝土、钢筋混凝土三种典型基层墙体结构的经济性.结果表明聚氨酯泡沫应用在三种基层墙体的经济厚度分别为53 mm、43 mm、62 mm,经济厚度适中、投资费用低且回收期短,适应性明显好于其他常用保温材料.其次分析了气凝胶保温材料对不同基层墙体的适用性,钢筋混凝土复合墙体由于投资回收期短,经济性及适应性较好.研究结果对于复合墙体的结构设计及气凝胶保温材料的建筑节能应用具有重要意义.     

空心墙体建筑的节能及经济性分析

对空心墙体的静态热阻计算考虑了对流和辐射对热阻的影响,并用非稳态传热理论和计算机模拟分析的方法,利用传递函数法求解新型节能空心墙体的传热过程,计算某建筑物的围护结构(传统实心墙体和新型空心墙体)的全年逐时能耗和总能耗,并根据计算结果进行节能分析和经济性分析,得出:建筑物采用节能空心墙体与传统实心墙体相比,夏季节能27 19%,冬季节能23 92%,其投资可在10a内回收。     

高层建筑的剪力墙体的结构设计策略探讨

随着社会经济和科学技术的发展,城市化进程日以加快,而高层建筑顺应城市化发展而逐渐兴起,剪力墙体结构,是一种在建筑物中主要承担风压荷载以及地震引发的水平或竖向中荷载的墙体,剪力墙又称挡风墙、抗震墙,被广泛应用于高层建筑、悬吊结构中。剪力墙体作为高层建筑中最核心的结构形式,其设计质量的好坏关系到高层建筑的总体的施工工程的成功与否。笔者将结合南昌市红谷滩的新地中心作为剪力墙体结构项目实例,探讨高层建筑的剪力墙体结构设计策略。     

轻钢与泡沫混凝土组合墙体抗剪承载力有限元分析

对轻钢与泡沫混凝土组合墙体应用于建筑结构进行推广,对6面组合墙体进行抗剪承载力试验,对其水平荷载峰值、开裂荷载、极限荷载、破坏形态进行测定,建立了轻钢与泡沫混凝土组合墙体ABAQUS有限元计算模型,有限元计算结果与试验结果吻合度较高,该模型可用于轻钢与泡沫混凝土组合墙体抗剪承载力的计算与分析。     

砖混房屋顶层墙体裂缝的结构设计问题

砖混结构房屋屋墙体受温度影响变形及其它原因易出现裂缝,文章从结构设计及施工等多方面探讨了裂缝产生的原因及相应的对策。     

高温隔热

前言自1973年石油危机以来,带来了能源价格的提高,重新估价隔热对于消耗能源的工业窑炉的节能问题显得更加重要。经济地使用高温隔热材料极大限度地依赖于适当地选择材料以及合理的墙体结构设计技术。本文主要涉及工业窑炉为隔热和有效地达到节能目的的墙体结构状况以及这方面的最近趋向。     

轻钢与泡沫混凝土组合墙体抗剪承载力计算研究

通过试验研究了轻钢与泡沫混凝土组合墙体的力学性能。研究表明:泡沫混凝土密度、含钢率等参数,对组合墙体破坏形态并无影响,但组合墙体的抗剪承载力受泡沫混凝土密度、含钢率影响较大。本文结合相关轻钢结构规范及理论,提出了轻钢泡沫混凝土组合墙体抗剪承载力计算公式,其计算结果与试验结果吻合度较高。研究成果可为轻钢与泡沫混凝土组合墙体抗剪承载力计算及力学性能分析提供重要参考。     

建筑结构设计中剪力墙结构设计的应用分析

剪力墙是建筑中的常用墙体结构之一,因其作用,又被称之为抗震墙、抗风墙以及结构墙等。剪力墙一般是用钢筋混凝土建成,用于承受风荷载、地震引起的水平荷载,以及重力引起的竖向荷载,通过承受荷载作用,防止建筑结构遭到剪切破坏,在建筑结构设计中发挥着重要的作用。本文首先分析了剪力墙结构的常见类型,并详细探讨了建筑结构设计中剪力墙结构设计的原则及优化策略。     

新型墙体材料生命周期能耗计算方法分析

采用生命周期能耗评价方法对墙体材料的能源消耗进行科学计算,通过分析生命周期能源消耗状况,给出了具体的墙体材料能耗计算方法,比较客观地描述了墙体材料的生命周期能耗状况,具有较强的可操作性和实际意义。     

人防地下室墙体结构设计浅述

人防地下室是建筑工程中比较重要的一个类别,这种人防工程项目的构建具备着较为明显的特殊性,需要结合自身的特点和功能进行恰当处理,确保其自身能够体现出较强的安全性和稳定性,发挥应有的性能,这也就要求重点针对人防地下室墙体结构进行合理设计,确保其合理性。本文就重点针对人防地下室墙体结构设计工作进行了简要的分析和论述。     

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.