花纹沟设计对轮胎花纹噪声的影响

根据轮胎花纹的发声机理,运用TNS/ODS噪声分析软件对185/55R14S-1200轿车轮胎花纹噪声的影响因素进行分析。综合模糊评判结果和M标准曲线目标函数分析表明：轮胎花纹沟与行驶方向的角度越小,噪声越低;花纹沟的宽度减小,轮胎整体花纹噪声降低;顺向花纹沟的噪声低于逆向花纹沟的噪声。     

胎面花纹设计对轮胎噪声的影响

采用光面胎花纹雕刻,研究胎面花纹设计对轮胎噪声的影响,分别考察花纹沟类型、横向花纹沟的深度和宽度、花纹节距、胎肩花纹沟开放形式和胎肩花纹沟角度的影响。结果表明:轮胎花纹是轮胎噪声的主要来源,可以通过优化胎面花纹结构来降低轮胎噪声;选择合适的花纹类型,优化花纹块(沟)的设计和花纹节距的排列顺序,选择合适的胎肩花纹沟开放形式和花纹沟角度均可以实现轮胎降噪。     

轮胎花纹噪声的发声模型

在分析轮胎花纹噪声发声机理的基础上,建立了轮胎花纹噪声各主要噪声源的发声模型,进而将花纹块和花纹沟的噪声波计权合得到时域波形,并通过离散傅立叶变换（用ＤＦＴ）,得到胎面花纹噪声的频谱,经过自动分析,评判,筛选出满意方案。为研究或设计低噪声轮胎花纹提出了依据。     

花纹沟深度对轮胎性能的影响

使用相同配方、结构及花纹但花纹沟深度不同的轮胎,通过室内外测试研究轮胎花纹沟深度对轮胎性能的影响。结果表明：减小花纹沟深度可以提高轮胎的干地制动性能、操纵性能和舒适性,降低噪声和滚动阻力,但会降低水滑性能和使用寿命;花纹沟深度对湿地制动性能、湿地操纵性能和湿圆环行驶性能影响较小。     

轮胎花纹噪声的发声机理

从声学理论和实验两方面对轮胎花纹噪声的发声机理进行了深入分析研究,得出花纹块的拍打撞击声、花纹沟的泵浦噪声、光面胎沙声及沟内气柱共鸣声是轮胎花纹噪声的主要噪声源。轮胎接地区域前沿、中央和后沿区由于各种因素生产振动所激发的辐射噪声强度以前沿区为最强,中央区次之,后沿区最小。在综合分析的基础上提出两条经验法则：一是轮胎花纹块的撞击声谱只和它的面积有关而与它的形状无关;另一条是花纹沟的泵浦噪声谱只和花纹     

轮胎花纹噪声的控制

从频域声能量均衡、时域声中心能量分布均衡和花纹沟气柱共鸣３个方面研究了花纹及其花纹块和花纹沟的结构与排列对轮胎噪声的影响,得出了低噪声轮胎花纹设计方法,并提出了轮胎花纹噪声控制的工作程序。     

轮胎噪声影响因素及低噪声轮胎设计方法

分析轮胎噪声影响因素,提出低噪声轮胎设计方法。胎面花纹形状、节距及排列、胎面胶配方以及轮胎均匀性等都对轮胎噪声有一定影响;采用尽可能多的节距数,减小花纹沟深度和宽度,适当降低胎面胶硬度,减小胎冠和胎侧刚度,提高轮胎均匀性等均有利于减小轮胎噪声。     

轮胎噪声的分析与测试方法

介绍国内外轮胎噪声的研究进展及测试方法。轮胎作为车辆与地面直接接触的部件,其产生的噪声对车辆性能影响很大。目前轮胎噪声的测试方法主要有滑行法、拖车法和室内转鼓法。国内轮胎企业应加大对低噪声轮胎的研究投入,深入分析轮胎噪声的发声机理,不断提高仿真精度,为降低环境噪声做出贡献。     

轮胎花纹噪声动力学分析

从动力学角度研究轮胎花纹噪声的发声机理。分析得出，车速越快、轮胎充气量越小、花纹块的密度越大，花纹块的噪声声压越大；花纹槽的腔体积、车速和汽车载质量越大，花纹槽的噪声声压越大。从噪声波干涉与合成的角度论述花纹结构参数对轮胎花纹噪声的影响。     

235/35ZR20 S-1087轿车轮胎低噪声胎面花纹的优化设计

介绍235/35ZR20S-1087轿车轮胎低噪声胎面花纹的优化设计情况。利用噪声分析软件确定胎面花纹优化设计方案为:胎面弓型主花纹沟曲线半径取130～160mm,连通沟倾斜角度为40～45°,花纹沟占行驶面面积比例为31%,胎面花纹从胎冠至胎肩连续、花纹沟延伸至胎肩花纹终点位置,左半花纹节距排列和右半花纹节距排列间错位30mm。优化轮胎的分析噪声不大于M标准曲线值,轮胎与路面间辐射产生的直接噪声以及汽车匀速行驶时车内噪声均比未优化轮胎降低,且通过欧盟ECE117噪声认证。     

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。