溢流法测定超临界CO_2在聚己酸内酯中的溶解

以超临界CO2作为溶剂,采用溢流法研究聚己酸内酯(PCL)在CO2中的溶胀过程和超临界CO2/PCL体系的热力学平衡规律。考察了温度、压力对溶解度的变化趋势,分析加入有机溶剂后对CO2在聚合物中的溶解度的影响,并应用P-T(Patel-Teja)方程作为热力学模型分析和计算溶解规律。结果表明:CO2的溶解度随温度升高而降低,随压力增大而增大,有机溶剂的加入能够进一步提高CO2的溶解度,在相同的温度压力条件下,加入相当于CO2质量的2.26%的二氯甲烷,最多可使溶解度增加28.06%。在温度313.15—353.15 K、压力10—20 MPa范围内,P-T方程能较好地预测CO2在PCL中的溶解度,其相对误差在-12.53%—12.01%。     

紫苏油在超临界CO_2中溶解度的神经网络模型建立

测定了紫苏油在超临界CO2 (SC CO2 )中的溶解度 ,利用误差逆传播 (BP)神经网络对溶解度数据进行了拟合。通过对萃取参数与溶解度的关系进行训练 ,实现网络结构的优化 ,建立了紫苏油在SC CO2 溶解度的网络模型 ,并将该模型用于一定范围内未知萃取参数下溶解度的预测 ,得到了较高的预测精度。结果表明 ,该方法可作为预测物质在SC CO2 溶解度的一种有效手段。     

一种测量超临界CO2在聚合物中溶解行为的新装置

设计了一种测量超临界CO2（ScCO2）在聚合物中溶解行为的装置,并通过测量温度在443.15~463.15 K,压力在7.5~9.5 MPa范围内ScCO2在聚苯乙烯（PS）中的溶解度及溶解速度验证装置的可行性。结果表明,溶解度实验值与计算值的相对误差低于20 %,而依据实验值计算的扩散系数与文献值表现出相同数量级,由此说明新装置能够进行ScCO2在聚合物中溶解行为的测量。     

CO2在聚乳酸中的溶解和扩散行为研究

采用统计力学的密度泛函理论,建立了CO2在聚乳酸中的溶解度计算理论模型,并利用非原位重力法测定了CO2在聚乳酸以及在聚乳酸/聚己二酸 对苯二甲酸丁二醇酯（PBAT）合金中的溶解度及扩散系数。将实验数据和理论计算结果对比,结果表明,DFT模型可以定量预测不同温度、压力条件下CO2在聚乳酸中的溶解度,而非原位重力法在低压下具有较高的准确性,且适用条件广泛;相比于纯聚乳酸,在不影响扩散系数的情况下,聚乳酸/PBAT合金具有更高的CO2溶解度。     

CO_2在混合胺MEA+DETA溶液中的溶解度

在温度298—338 K,压力300—700 kPa,吸收剂浓度1—3 mol/L的实验条件范围内,讨论了CO2-吸收剂体系气液二相基本达到平衡时,CO2吸收量与体系温度,压力及吸收剂浓度的关系。根据亨利定律,引入温度及压力相关因子,建立了CO2在单胺溶液中的溶解度模型。模型对CO2在MEA、DETA单胺溶液中的溶解度预测效果较好,与实验值比较,误差在1%以下。引入增强因子β=1.06,并以单胺在混合胺溶液中的摩尔分数为系数,将CO2在单胺溶液中的溶解度叠加获得CO2在MEA+DETA混合溶液中的溶解度模型。模型对MEA+DETA混合胺的预测误差在1%—10%。     

水合物存在条件下CH_4和CO_2在溶液中溶解度计算

实验测定了在不同温度、压力条件下,水合物存在时CO2和CH4在水溶液中的溶解度。将Chen-Guo水合物模型和拓展的P-T状态方程应用到水合物存在条件下CH4和CO2在溶液中的溶解度计算,对于V-Lw-H三相条件下CH4和CO2在液相中的溶解度取得了较高的计算精度。本文将vander Waals-Platteeuw模型和拓展的P-T状态方程结合,建立了用于计算高于三相平衡压力条件下CH4和CO2在液相中溶解度的模型。考察了系统压力对CH4和CO2在液相中溶解度的影响。结果表明,压力增加会显著影响CH4和CO2在其溶液中的溶解度。模型基于两点假设经过改进后具有较高的计算精度,能够用于水合物存在条件下CH4和CO2在液相中溶解度的计算。     

CO_2在固态聚丙烯/滑石粉复合材料中的溶解和扩散

利用重量分析的方法测定了温度分别为343.15、373.15和393.15 K,压力0~16 MPa范围内,CO2在聚丙烯(PP)、PP/滑石粉和界面改性PP/滑石粉复合材料中的溶解度和扩散系数。CO2在未经界面改性PP/滑石粉复合材料中的溶解度低压下大于而高压下小于其在纯PP中的溶解度,在经过界面改性的PP/滑石粉复合材料中的溶解度小于其在纯PP和未经界面改性复合材料中的溶解度。CO2在PP/滑石粉复合材料中的扩散系数小于其在纯PP中的扩散系数,填料含量越大扩散系数越小。通过S-L状态方程关联了CO2在纯PP和经过界面改性的PP/滑石粉复合材料非晶区的溶解度,并计算了CO2对聚合物基体的溶胀情况,证实了填料对聚合物分子链运动的阻碍作用。     

齐墩果酸在超临界CO2中的溶解度研究

采用静态平衡差重法测定了齐墩果酸在超临界CO2中各个状态点的溶解度,考查了温度、压力、密度等因素对齐墩果酸在超临界CO2中溶解度的影响,并采用Chrastil模型对实验数据进行分析计算。实验结果表明：齐墩果酸在超临界CO2中的溶解度随着压力的增加而增加,20MPa条件下的密度与溶解度符合一定的函数关系。     

CO2在醇中溶解度的测定与分子连接性指数的关联

用恒定溶剂法测定了303.15K下CO2在乙醇、正丙醇、异丙醇、正丁醇、正戊醇、异戊醇、正己醇、正辛醇、乙二醇、1,2-丙二醇中的溶解度。实验表明:随着碳链的增长,吸收CO2的效果越好,CO2在正辛醇中的溶解度最大,CO2在二元醇中的亨利常数显著大于一元醇。利用线性回归方法建立CO2在醇中的亨利常数lgH与分子连接性指数的相关关系模型,模型计算简单易行,对CO2在醇中的亨利常数有良好的估算和预测能力,相关系数R>0.99,计算值和实验值吻合良好。研究表明:用一阶分子连接性指数1χv、羟基的个数N、经验参数COH三个参数可以描述CO2在醇中的溶解特性lgH,且精确度很高。     

超支化含苯基聚硅氧烷亲二氧化碳特性及其分子模拟

通过水解缩聚法制备含有不同苯基含量的超支化聚硅氧烷，探究苯基的引入对超支化聚合物在CO2中溶解性能的影响。浊点压力测试得出苯基的引入在超支化结构中对聚合物在CO2中的溶解度影响不大，超支化聚合物中苯基含量的增加没有导致浊点压力的明显升高，有望实现作为CO2增稠剂兼具较好的溶解度和增稠性能。分子模拟计算分析了超支化聚硅氧烷和直链聚硅氧烷与CO2分子间的相互作用以及超支化聚硅氧烷分子间的相互作用，发现含苯基的超支化聚硅氧烷具有更低的内聚能密度（CED）和溶解度参数（δ），表现出更弱的聚合物分子间相互作用，有利于超支化有机硅氧烷在CO2体系中的溶解。     

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。     

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.     

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。     

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.