碳纤维复合材料在无人机上的应用

介绍了碳纤维复合材料在无人机上的应用优势,对世界上几种先进的无人机上的碳纤维复合材料应用情况进行了简介,并对未来无人机用碳纤维复合材料的研究发展趋势进行了分析和探讨。指出完善的设计和工艺体系、降低材料成本、开展结构设计研究、研发新的成型工艺、发展隐身技术和低成本快速修复技术是未来研发趋势。     

复合材料叶片结构设计中的几个关键问题探讨

风力发电技术作为新兴技术,欧美一些国家已发展到相当高的水平,我国风力发电近些年也发展迅猛。风力发电的关键技术之一是风力机复合材料叶片的设计与研制,涉及到空气动力学、结构力学、复合材料力学及成型工艺等。本文着重探讨复合材料叶片的结构设计中几个关键的问题,在广泛分析和研究国内外复合材料结构设计现有技术基础上,并结合实际的研究经验,对复合材料叶片结构设计中的材料选择、载荷工况、结构选型、铺层设计以及力学分析等关键环节进行探讨和分析,并给出可行的意见。     

直升机旋翼复合材料桨叶结构设计与选材分析

介绍了直升机旋翼复合材料桨叶的结构特点和设计要求,分析了国内外复合材料桨叶结构设计的选材情况,总结了我国直升机复合材料桨叶结构选材现状与现存问题,并对无轴承旋翼柔性梁和主动控制智能旋翼国际新型桨叶复合材料结构设计与选材进行了讨论。综述研究表明,直升机旋翼桨叶工作环境复杂,在动力学设计方面有较高要求,复合材料桨叶结构设计及其成本与选材存在相互依赖和相互制约的矛盾关系,指出桨叶用复合材料与其结构设计技术的发展,对提高我国直升机旋翼桨叶性能、可靠性、寿命和安全性具有重要意义。     

有经济效益地在桥梁上应用先进复合材料的设计方法和桥梁形式

分析了影响在桥梁上应用先进复合材料经济效益的因素,继之以考察正用于设计和建造先进复合材料结构物(包括桥梁)的设计方法和规范。介绍了不同的桥梁形式证明可采用先进复合材料(有时连同其它材料),并列举了对委托方和桥梁使用者的实惠。     

对桥梁施工技术的几点看法

现代桥梁设计技术的发展,使得众多国家对加大对桥梁结构设计理论方面的研究。通过简要说明桥梁设计的注意事项。对现代桥梁结构设计的理论和设计中常见的问题做简单探讨及实践中混凝土桥梁裂缝的分类及成因,提出混凝土桥梁裂缝的几种修补方法,包括表面封闭修补法、压力灌浆法、黏贴钢板施工法等。基于震害现象和有关实验与理论研究,结合能力抗震设计的思想,按照我国公路桥梁的特点,探讨影响极限强的因素,并提出抗震设计的方法,具有重要的论意义和工程应用价值。     

复合材料输电杆应用进展

介绍了复合材料输电杆技术研究及应用现状、复合材料电杆市场及生产厂家。详细阐述了原材料选择、结构设计、成型工艺及国外对复合材料电杆应用标准及性能试验情况,并对复合材料电杆的性价比进行了分析并展望了其未来的发展前景。     

基于SQLite的航空典型复合材料性能数据模型的高效设计与应用

伴随着复合材料在航空结构应用比例的不断加大,先进的数字化设计技术和CAE分析技术等在复合材料设计领域得到深入应用。在现代飞机数字化研制进程中,材料选用、强度分析、结构设计、材料生产和零件制造等工作必须依赖大量的材料性能数据的支撑。因此,本文针对CAE分析过程中对航空典型复合材料性能数据的需求,采用SQLite数据库技术,提出了一种轻量级材料数据结构和标准模板的高效设计方法,构建了材料数据库的底层数据模型。同时结合工程需求,基于Qt和C++混合编程方法开发了一款国产航空复合材料性能数据库软件,并通过设计材料数据应用接口实现材料数据的更新和下载,为CAE分析流程提供了数据支撑,从根本上保证材料数据的一致性,验证了本文设计方法的有效性和实用性。     

桥梁结构设计中减隔震技术的应用

随着我国社会经济的快速发展,公路桥梁的建设逐渐被重视,在对桥梁结构设计中对减隔震技术进行应用成为桥梁质量安全保障的关键。减隔震技术作为最新的桥梁抗震技术,主要运用于对路段结构进行设计的过程中。本文主要对减隔震技术的相关概念以及适用的条件进行阐述,并对减隔震技术在桥梁结构的设计的分类进行分析研究,从而使施工过程中对减隔震技术的运用提供依据,并使工程的设计得以完善。     

复合材料的研究动向

一、概 述 复合材料研究的目的,是把性能不同的两种或两种以上的材料组合起来,有效地利用各自的长处,弥补各自的短处,生产出性能优良的材料。 复合材料是可设计的,其结构件的设计是材料设计与结构设计同时或交错进行,这种结构设计为进行优化设计提供了更大的自由度。但是,为了做到这一点,就需要事先能够预测复合的效果。近年来,由于复合材料力学的进步,以及电子计算机的有限元法分析在复合材料研究中应用的发展,因而能够对复合材料进行相当可靠的最佳设计。     

基于CATIA的复合材料结构优化设计

简述了CATIA软件在复合材料结构设计中的应用,利用CATIA设计软件中的Composit Design(复合材料设计)和Generative Structural Analysis(有限元结构分析)模块对复合材料方形盖体进行三维实体结构设计与力学分析。通过计算得出了方形盖体的工艺角α=14°时,方形盖体的密封面变形最小,优化了方形盖体的结构,利用CATIA中的Core&Cavity Design(阴阳模设计)模块设计出复合材料方形盖体的阴阳模。     

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。