生物凝固天然橡胶在子午线轮胎中的应用

研究生物凝固天然橡胶(NR-B)在子午线轮胎中的应用,并与马来西亚20#标准胶(SMR20)进行对比。结果表明:与SMR20相比,NR-B的塑性初值和塑性保持率较高,纯胶配方硫化胶拉伸强度较大,定伸应力较小;采用NR-B的胎面胶、基部胶、胎肩垫胶和粘合胶拉伸强度、拉断伸长率和撕裂强度等关键性能均与采用SMR20的硫化胶相当,但采用NR-B的胶料普遍存在ML偏高的现象。成品轮胎性能测试结果表明,采用NR-B的轮胎高速性能和耐久性能与采用SMR20的轮胎相当,耐磨性能差别不大。     

海南天然橡胶在全钢越野子午线轮胎胎面胶中的应用

研究海南天然橡胶在全钢越野子午线轮胎胎面胶中的应用,并与马来西亚天然橡胶SMR20进行对比。结果表明:海南天然橡胶的杂质质量分数及氮质量分数均低于SMR20;将海南天然橡胶替代马来西亚天然橡胶SMR20用于越野轮胎胎面胶,胶料的拉伸性能、抗撕裂性能和抗切割性能稍好,脆性温度基本相同,生热较低;成品轮胎耐久性试验和高速性能试验顺利通过验证,海南天然橡胶轮胎的高速性能较好。     

天然橡胶种类对白炭黑填充胶性能的影响

研究了天然橡胶种类对白炭黑填充天然橡胶性能的影响。研究结果表明:与恒黏胶(SMR CV)和3号烟片胶(RSS 3)相比,白炭黑在20号标准胶(SMR 20)中的分散更好。由于白炭黑分散较好且非橡胶成分含量高,应变诱导结晶能力强,因此SMR 20硫化胶具有更好的力学性能,比如更高的拉伸强度、撕裂强度、回弹性和更低的动态压缩生热。     

航空子午线轮胎胎侧胶配方的优化设计

对航空子午线轮胎胎侧胶配方进行优化设计。试验结果表明:胎侧胶优选配方为天然橡胶65,顺丁橡胶35,炭黑N375 50,增粘树脂Koresin 2,防老剂5.5,不溶性硫黄1.8,促进剂TBBS 0.8,其他8.7;与生产配方胶料相比,试验配方胶料的门尼焦烧时间延长,加工安全性和抗硫化返原性能提高,硫化胶的密度减小,拉伸强度、拉断伸长率和撕裂强度增大,耐低温和耐屈挠性能提高;成品轮胎的导电性能达到相关标准要求。     

NR/SR并用对全钢载重子午线轮胎胎面胶性能的影响

试验研究NR与SR(SBR或/和BR)并用对全钢载重子午线轮胎胎面胶性能的影响.结果表明,与单用NR相比,SR用量不超过20份的NR/SR混炼胶强度略低,硫化胶的硬度、定伸应力、拉伸强度、拉断伸长率、弹性和耐磨性能相近,拉断永久变形较小,压缩温升略高;SR用量超过20份的NR/SR混炼胶强度较低,硫化胶的300%定伸应力和撕裂强度较低,压缩温升较高,耐磨性能较好.NR与不超过30份(最好为20份)的SBR/BR(不超过20份,最好为10份)并用的全钢载重子午线轮胎胎面胶性能较好.     

三种NR的应用性能比较

将生物凝固天然橡胶(NR-S)、酸凝天然橡胶(NR-A)和马来西亚20号标准胶(NR-M)三种生胶原料应用于子午线轮胎,进行了胎面胶、粘合胶和胎肩垫胶的小配合试验。试验表明,各配方中以NR-S为生胶原料得到硫化胶拉伸强度、撕裂强度、拉断伸长率、抽出力等关键性能均比使用NR-M高;从机械性能、耐老化性能综合考虑,NR-S优于NR-A。     

国产天然橡胶标准胶与进口天然橡胶的性能对比研究

对国产10号标准天然橡胶(SCR10)、20号标准天然橡胶(TSR20)和进口的泰国20号标准天然橡胶(STR20-C)、马来西亚20号标准天然橡胶(SMR20)以及泰国3号风干烟片(RSS 3#)的性能进行了对比研究。结果表明,RSS 3#的物理交联密度最高,且耐屈挠龟裂和抗硫化返原性能优异,但其加工及动态性能均较差。另外,SMR20、STR20-C的加工性能和低滚动阻力特性优于SCR10、TSR20。在拉伸力学、动态力学、耐屈挠龟裂、抗硫化返原等性能方面,SCR10、TSR20与STR20-C、SMR20相近。     

全SBR在全钢载重子午线轮胎胎面冠部胶中的应用

研究全SBR在全钢载重子午线轮胎胎面冠部胶中的应用情况。结果表明:通过调整配方,全SBR胶料的拉伸强度、拉断伸长率、抗切割性能和耐磨性能等与生产配方胶料相比均有较大改善;试验轮胎的耐久性试验和实际道路试验结果与正常生产轮胎相比无明显差异,但生产成本降低。     

国产BIIR2302在全钢载重子午线轮胎气密层胶中的应用

研究国产溴化丁基橡胶(BIIR)2302在全钢载重子午线轮胎气密层胶[天然橡胶/BIIR并用胶(并用比为20/80)]中的应用。结果表明:与采用进口BIIR2222的气密层胶相比,采用BIIR2302的气密层胶硫化速度和加工安全性相当;气密性差异不大,拉断伸长率较大,其他物理性能相近;工艺性能较好;成品轮胎耐久性能略好。BIIR2302完全可以替代BIIR2222用于全钢载重子午线轮胎气密层胶中。     

有机锌在全钢载重子午线轮胎胎侧胶中的应用

研究有机锌替代氧化锌在全钢载重子午线轮胎胎侧胶中的应用。结果表明:与氧化锌胶料相比,有机锌胶料的MH较大,硫化速度相当,拉伸强度和定伸应力较大,耐热老化性能提高。在全钢载重子午线轮胎胎侧胶中,有机锌可等量替代氧化锌使用。     

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.     

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。     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。     

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.