用于RTM工艺的软模材料的热膨胀性能

建立了用于RTM工艺的软模材料的热膨胀—温度特性的测试方法,得到了软模材料的热膨胀参数。研究结果表明,和聚氨酯泡沫及R311硅橡胶相比,COCA31-11硅橡胶随温度上升能产生较大的膨胀力,因此初步确定COCA31-11为本文研究工作的软模材料,其在室温至180℃范围内线胀系数为2.65×10-4/℃、体积膨胀系数为8.26×10-4/℃,在室温至80℃范围内两个方向受约束时第三个方向上的表观线膨胀系数为6.78×10-4/℃、体积弹性模量为510MPa。     

RTM工艺中硅橡胶气囊模具的应用研究

由于用传统RTM工艺整体成型复杂结构复合材料构件有一定困难，所以用硅橡胶气囊模具代替RTM工艺中的金属阳模，并对这一工艺过程进行研究。通过硅橡胶力学性能试验，得出用硅橡胶的拉伸、撕裂、剥离强度等性能指标，可以满足气囊模具的要求。利用硅橡胶气囊辅助RTM工艺，可以制作纤维体积含量较高的复合材料构件。与其他模具相比，硅橡胶模具具有很多优点。研究表明，纤维体积含量随气囊内压力的增加而增加。     

中压中间接头模具的设计

介绍了使用液态硅橡胶硫化成型的电缆附件中压中间接头产品的模具设计,其中包括应力锥、屏蔽管和绝缘体3种产品的模具结构;探讨了用于立式和卧式合模单元成型绝缘体硫化模具的结构特点以及产品成型工艺中常见问题的解决方法。对于了解、设计中间接头产品硫化模具和优化产品成型工艺具有参考意义。     

3D打印技术在硅橡胶浇注模中的应用研究

膨胀成型是复合材料典型的成型方法,采用膨胀成型的复合材料制品需要通过硅橡胶浇铸模来辅助成型,为了缩短硅橡胶浇注模的制造周期,本文研究采用3D打印技术打印硅橡胶浇注模。针对R-10301硅橡胶浇注模,本文通过对比常用的3D打印技术和常用打印材料的特性,确定了采用SLA光固化成型工艺并选择somos 8000光敏树脂打印硅橡胶浇注模;通过浇注实验得到的硅橡胶芯模,其尺寸偏差控制在±0.1mm范围内,脱模过程中无粘模现象;且模具相比传统金属模重量更小,制造周期更短。     

氟橡胶/硅橡胶并用胶性能的研究

考察了不同的共混工艺对氟橡胶/硅橡胶并用胶的硫化特性、力学性能、耐热油性能、耐热老化性能以及动态力学性能的影响.实验结果表明:双硫化体系#试样硫化速度快,硫化平坦性好,硫化胶的拉伸强度达到10MPa;硅橡胶动态预硫化后再并用,其力学性能较差;三种并用胶的DMA曲线在-40℃和0℃附近分别显示硅橡胶和氟橡胶的阻尼峰,三者的tanδ相差不大,不同制备方法对氟橡胶和硅橡胶的相容性有一定影响.     

硅橡胶/丁苯橡胶并用胶的制备及表征

针对硅橡胶具有较高的耐热性,但力学性能差;丁苯橡胶(SBR)力学性能较好,但粘性较差;提出了将硅橡胶与SBR共混,制成共混材料;采用偏光显微镜、傅里叶变换红外光谱、差示扫描量热仪以及力学性能、热老化性能测试手段,研究了甲基乙烯基硅橡胶(MVQ)/SBR共混体系的并用比(质量比)、硫化工艺参数以及顺丁橡胶(BR)的加入对力学性能、耐热老化性能和相容性的影响。结果表明:MVQ与SBR最佳配比为30/70,白炭黑为45份;最佳硫化工艺参数为170℃×10 MPa×30 min。MVQ/SBR并用胶的玻璃化温度为-20℃,MVQ和SBR具有较好的相容性。     

注射模硫化成型工艺在轨道减震器中的应用

研究注射模硫化成型工艺在轨道减震器中的应用,并与传统高压模硫化成型工艺进行对比。结果表明：与采用高压模硫化成型工艺相比,采用注射模硫化成型工艺可以缩短产品硫化时间,提高生产效率;增大产品内压,提高橡胶硫化均一程度,增大橡胶-金属粘合强度;减小产品疲劳试验后垂向静刚度、垂向动刚度和动静刚度比的变化,使用过程中产品性能更为稳定。     

4种网格结构模具用硅橡胶性能研究

分析了网格结构模具用4种不同的室温硫化硅橡胶的性能结果表明,该4种硅橡胶均具有较小的线收缩率及较长的凝胶时间,但加成型室温硫化硅橡胶较缩合型硅橡胶具有突出的室温力学性能、热稳定性及热线胀性能,完全满足用于制作网格模具的硅橡胶要求.     

注射模硫化成型工艺在轨道减震器制备中的应用

研究注射模硫化成型工艺在轨道减震器制备中的应用,并与传统高压模硫化成型工艺进行对比。结果表明:与采用高压模硫化成型工艺相比,采用注射模硫化成型工艺可以缩短产品硫化时间,提高生产效率;增大产品内压,提高橡胶硫化均一程度,增大橡胶-金属粘合强度;减小产品疲劳试验后垂向静刚度、垂向动刚度和动静刚度比的变化,使用过程中产品性能更为稳定。     

新型硅橡胶胶管生产工艺

由刘建平申请的专利（专利号CN1302912,公开日期2006—06—28）“新型硅橡胶胶管生产工艺”,涉及一种新型硅橡胶胶管生产工艺及其专用模芯。该新型硅橡胶胶管生产工艺如下：（1）在与胶管内径相适应的胶囊表面上直接成型胶管毛坯;（2）将成型好的胶管毛坯连同胶囊一起放入模具模腔中;（3）合模,向胶囊内部打入内压,进行硫化;（4）硫化完成,卸压,拔出胶囊,     

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。     

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.     

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.     

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.