纤维复合材料在装甲防护上的应用

反装甲武器威力的飞速发展,迫使装甲防护材料必须具备轻质高强、优异的防弹性能及耐疲劳等性能.本文首先阐述了在装甲防护上纤维复合材料的优点和防弹机理,其次介绍了国外复合材料在装甲防护上的研究应用现状和新型研制技术,主要包括玻璃纤维、芳纶纤维、UHMWPE纤维以及PBO纤维等复合材料,然后介绍了我国纤维复合材料的研究及应用现状.最后结合我国目前的研制情况,提出了复合材料装甲的研究发展方向.     

装甲车用新型高性能防弹复合材料技术研究

树脂基复合材料以其防护性能好、密度低及制备工艺简单等优点广泛应用于装甲防护领域。本文研究了不同纤维三维织物与陶瓷片厚度等因素对防弹复合材料性能的影响。最后指出,在进行防弹复合材料设计与开发时,应考虑防弹性能、重量与成本之间的关系,只有三者达到平衡,才能设计出满足实际使用要求的防弹复合材料。     

新型复合防弹装甲结构材料的研究

通过分析陶瓷与复合材料的防弹机理,借助数值模拟分析技术对复合装甲的结构进行设计,并制备靶板,研究了复合装甲的材料与结构形式对防弹性能的影响,通过打靶实验,验证了结构设计的科学性及合理性.本文还在防弹装甲结构中尝试橡胶材料的应用,靶试结果表明,橡胶在防弹性能上具有明显作用.     

复合材料多功能防弹板防弹性能研究

虽然单一的装甲钢或芳纶板具有良好的防高速弹丸贯穿性能,但采用复合结构可以大大提高单一防弹板的防弹效率,减轻防护板面密度。通过弹道实验和数值模拟方法研究了装甲钢复合芳纶泡沫夹层结构抗56式7.62mm普通钢芯弹贯穿特性;探讨了不同复合形式的装甲钢复合芳纶泡沫夹层结构抵抗弹丸的防护效能和影响防弹板吸收子弹动能的因素;提出了该种装甲钢复合芳纶泡沫夹层结构最佳防弹速度区间的概念和相应的V50估算公式,由此可以设计出防弹效费比最佳的防弹板。     

防弹车辆用陶瓷复合装甲研究

将陶瓷材料应用于防弹领域之中已成为近年来国内外研究的热点,陶瓷复合装甲的结构设计对防弹车辆的防护性能至关重要。从防弹车辆防护等级要求入手,以陶瓷/纤维复合装甲防弹机理为依据,从陶瓷面板、背板材料和约束形式三个方面出发,探讨陶瓷复合装甲防弹性能的主要影响因素。重点讨论陶瓷力学性能、尺寸、形状、厚度、背板及约束方式等要素对防弹性能的影响,寻求提高陶瓷复合装甲防弹性能的有效途径,为今后陶瓷复合装甲的结构设计提供理论基础和研究方向。     

纤维增强复合材料对破甲弹的防护性能研究

采用真空辅助成型工艺制备纤维增强复合材料。分别以装甲钢、纤维增强复合材料作为轻型反应装甲的面、背板,考察轻型反应装甲对破甲弹的防护性能。结果表明,在考察范围内,复合材料组成的轻型反应装甲的防护性能较好,其中碳纤维增强复合材料的防护系数可达到23.9,并可消除传统反应装甲的二次毁伤效应。     

装甲钢/芳纶复合材料防爆轰波性能研究

利用防爆轰波模拟试验装置研究了由装甲钢和芳纶复合材料组成的不同复合结构对爆轰波的防护性能。结果表明,以装甲钢为面板的装甲钢/芳纶复合材料的复合结构的防爆轰波性能优于以芳纶复合材料为面板的芳纶复合材料/装甲钢复合结构;装甲钢/芳纶复合材料的防爆轰波性能优于装甲钢/装甲钢的防爆轰波性能。     

UHMWPE纤维/LDPE复合材料防弹性能及机理研究

本文探讨了用超高分子量聚乙烯（UHMWPE）纤维增强低密度聚乙烯（LDPE）复合材料的防弹性能，研究了不同基体含量对复合材料防弹性能的影响。实验证明，UHMWPE纤维／LDPE复合材料具有较好的防弹性能，其最佳的基体含量在26％左右。同时，本文还通过分析防弹片材的断裂区域及复合材料的防弹机理确定了弹丸的变形情况和靶片“背凸”在防弹作用中的贡献。     

PBO纤维复合材料抗弹性能研究

采用铺层模压的方式制备了聚对苯撑苯并二恶唑(PBO)纤维织物增强复合材料,并研究了其防弹特性。通过大量实弹试验,分析了不同树脂基体、不同纤维含量、不同铺层方式等因素对PBO纤维复合材料抗弹性能的影响。结果表明,采用EVAC胶膜作为树脂基体,PBO纤维体积分数在70%～80%时,其复合材料的抗弹性能最佳。     

剑麻纤维/玄武岩纤维混杂增强聚乳酸复合材料的力学性能研究

混杂纤维增强复合材料由于可以综合利用各种纤维的优点,极大地提高复合材料的性能,拓展复合材料的适用范围。采用剑麻纤维和玄武岩纤维混杂增强聚乳酸制备复合材料,研究了纤维含量和铺层顺序对混杂纤维复合材料力学性能的影响。结果表明,剑麻纤维作为芯层、玄武岩纤维作为表层时混杂复合材料具有较好力学性能。当纤维质量分数为40%时,其拉伸强度和冲击强度比纯聚乳酸分别提高了2.83倍、41.47倍,达到了267.29 MPa和183.46k J/m~2;纤维含量为30%时,其弯曲强度比纯聚乳酸提高4.07倍,达到354.16 MPa。     

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.     

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。     

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.     

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.     

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.