脂肪酸稀土用作PVC热稳定剂的压析和喷霜特性

研究了常见脂肪酸的稀土盐用作ＰＶＣ热稳定剂的压析和喷霜霜特性。结果表明,与常用金属皂（如钙、锌皂）有所不同,硬脂酸稀土不但喷霜小,压析也小;脂肪酸稀土的压析和喷霜具有相似的递变规律;硬脂酸稀土一棕榈酸稀土－肉豆劳动酸衔土～月桂酸稀土〈葵酸稀土〈辛酸稀土。     

PVC用稀土热稳定剂的研究进展

介绍了单一稀土和稀土—铅,稀土—有机锡及稀土—锌等稀土复合热稳定剂的研究现状,探讨了稀土复合热稳定剂的作用机理,并分析了稀土热稳定剂的发展前景。     

PVC新型无毒热稳定剂研究进展

概述了聚氯乙烯的热降解与稳定化机理，着重介绍了稀土稳定剂、有机锑稳定剂、钙／锌稳定剂、水滑石稳定剂等热稳定剂的特点、作用机理及其发展趋势。     

聚氯乙烯无毒热稳定剂的研究进展

概述了聚氯乙烯的热降解机理及热稳定剂的作用机理。重点介绍了稀土稳定剂、有机锑稳定剂、钙/锌稳定剂、水滑石稳定剂等热稳定剂的研究发展情况。     

环氧脂肪酸稀土的合成及其对PVC热稳定作用的研究

制备了环氧基保留完好的高纯度环氧脂肪酸稀土。研究发现环氧脂肪酸稀土对PVC的热稳定作用类似于硬脂酸稀土，具有长期型热稳定剂的特征，但其热稳定效能明显优于后者，可代替硫醇辛基锡达50%而不降低热稳定性，而硬脂酸稀土只能代替约25%。     

无铅化稳定剂应用研究进展

本文介绍了无铅化稳定剂的应用现状,重点介绍了无铅化稀土复合稳定剂的作用特性及在UPVC制品中的应用,对稀土化合物的稳定机理进行了探讨。研究表明WWP稀土/钙/锌复合稳定剂无毒、高效、多功能,属新一代绿色环保产品,是具有中国特色的值得大力发展的PVC无铅化热稳定剂。     

稀土复合稳定剂在PVC加工中的应用

研究了以氯化钕为代表的稀土稳定剂在PVC加工中的应用情况，提出了稀土稳定剂的机理，并用稀土稳定剂生产出合格的U－PVC饮用水管。     

稀土钕(Nd)在聚氯乙烯加工中的热稳定性研究

研究表明,在用钡/锌复合物稳定剂作PVC及PVC/ABS合金的加工过程中,加入少量稀土钕化物,特别是在有能改善其初期着色性的助剂存在下,可大大提高其热稳定性。对用钕 钡/锌复合稳定剂所制备的PVC塑料及PVC/ABS合金来说,当与聚氨基甲酸酯泡沫塑料接触时,其稳定性更是出奇的好。对稀土化合物的稳定机理进行了探讨,认为稳定作用来自3个方面:变价元素、类金属皂作用和稀土络合作用。     

绿色环保PVC热稳定剂的研究进展

概述了聚氯乙烯(PVC)的热降解与稳定化机理,重点介绍了稀土稳定剂、钙/锌稳定剂、水滑石稳定剂及辅助稳定剂的种类与作用、复配的协同作用机理.指出随着人们的环境意识增强和相关的法律法规的执行,PVC的热稳定剂向着无毒、环保的方向发展.     

一步法合成新型稀土复合热稳定剂

研究了一种新型PVC稀土复合热稳定剂的合成工艺以及热稳定效果。用一步法合成了两种PVC稀土复合热稳定剂,讨论了两阶段碱分配比、各阶段反应时间、反应温度以及锌、钙、钡的含量对PVC稀土复合热稳定剂热稳定性的影响。结果表明:合成稀土-锌-钙复合稳定剂工艺条件是70℃、5min、15min、20min,稀土-锌-钡热稳定剂是65℃、15min、20min、5min,静态热稳定测试表明产物中的硬脂酸稀土与硬脂酸金属盐之间有良好的协同作用,两种复合稳定剂的静态稳定时间分别为18.6min、17.5min。     

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.     

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.     

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。