四丁基氟化铵在DMF中的活度系数测定

采用电导法测定了298.15~343.15 K下四丁基氟化铵（TBAF）在DMF中的电导率,计算出TBAF在DMF中的摩尔电导率;根据Kohlrausch规则,采用外推法求出TBAF在DMF中的无限稀释摩尔电导率;采用DebyeHücker和Osager-Falkenhangen公式计算出TBAF在DMF中的平均活度系数,并讨论了TBAF电解质溶液活度系数的影响因素。结果表明,其活度系数随溶液浓度的增大和温度的升高而减小。     

一个物理化学设计实验的探讨与改进——离子液体溶液平均活度系数的测定

文章制备了溴化1-十二烷基-3-甲基咪唑[C12mim]Br和1-十二烷基-3-甲基咪唑四氟硼酸盐[C12mim][BF4]两种离子液体。在不同温度下,测定了两种离子液体水溶液的电导率,根据电导率-浓度曲线转折点求出了两种离子液体水溶液的临界胶束浓度。由Debye-Hücker和Osager-Falk-enhangen公式计算出离子液体的平均活度系数。结果表明：[C12mim]Br和[C12mim][BF4]的水溶液临界胶束分别为5.75×10-3 mol·L-1和6.00×10？3 mol·L-1。25℃下,平均活度系数随浓度的增大而降低。     

NaBr,NaCl和KBr在几种有机溶剂中活度系数的测定

分别测定了NaBr在甲醇、乙醇、正丙醇和异丙醇中,NaCl和KBr在甲醇和乙醇中共8个体系（溶液物质的量的浓度在01 mol·L-1范围内）在29815、31315和32315 K下的电导率,利用Debye Hücker和Osager Falkenhangen 公式计算了以上溶液体系的平均离子活度系数,讨论了浓度和温度对电解质溶液活度系数的影响。其中NaBr 在乙醇中, NaCl在甲醇中和 KBr在甲醇中的平均离子活度系数的计算结果与已发表文献中的数据进行了比较。结果表明,该方法的活度系数结果与文献数据有较好的一致性。 关键词：电解质溶液;电导法;平均离子活度系数;有机溶剂;NaBr; NaCl;KBr     

[1ChCl:2EG]/CrCl_3?6H_2O低共熔溶剂的物化性质

实验研究了低共熔溶剂[1Ch Cl:2EG]/Cr Cl3?6H2O的熔点、密度、表面张力、粘度和电导率与Cr Cl3?6H2O浓度和温度的关系.结果表明,[1Ch Cl:2EG]/Cr Cl3?6H2O的最低共熔点为211 K,具有较宽的低温液程;密度与温度呈良好的线性关系并随Cr Cl3·6H2O浓度升高略微增大;表面张力比水小但比传统的有机溶剂高,并随Cr Cl3?6H2O浓度升高而略微增大;温度从293 K升高到343 K,[1Ch Cl:2EG]/Cr Cl3?6H2O的粘度显著降低,而电导率则明显增大,Cr Cl3?6H2O浓度为0.3 mol/L时,该溶剂体系粘度最小,电导率最高;Cr Cl3?6H2O和[1Ch Cl:2EG]/(0.3 mol/L)Cr Cl3?6H2O在923 K下分解后产物都是CRO3;1Ch Cl:2EG和[1Ch Cl:2EG]/(0.3 mol/L)Cr Cl3?6H2O均可在383 K内保持稳定.     

溴化锂水溶液分子扩散系数的计算方法

本文从电解质溶液理论出发,导出了不同温度和不同浓度下溴化锂水溶液的平均活度系数的计算表达式。又借助于Gorden半经验公式,得到了计算溴化锂水溶液分子扩散系数的理论计算公式。计算结果与T.Kashiwagi等采用全息干涉法所观测到的结果完全吻合。     

带固溶体的水盐体系相平衡热力学关联

对带固溶体的MX-NX-H2O三元体系，提出了计算固溶体组份的活度系数公式1n γ1＝a1-bα1^1/3 sα1^4/3。在固相组份不完全互溶时，给出了描述固相活度系数的关系式。利用该关系式，只需一个参数(如一个组份无限稀的活度系数)，即可推算出液固相干涝数据。以NH4Cl—KCl—H20三元体系为例，推算得出的结果与实测数据能很好吻合，平均相对误差为3．67％。     

不同温度下氯化钙-葡萄糖-水体系的活度研究

用一个钙离子选择性电极(Ca-ISE)和一个氯离子选择性电极(Cl-ISE)作参比电极组成的电池测定308.15 K和318.15 K下水中CaCl2-葡萄糖体系的平均活度系数,糖的浓度从0.1~2.0 mol·kg-1,此法和用其他电动势法测得的结果一致性相当好。同时,结合参考文献的其他数据综合比较了不同温度下活度系数随浓度及温度的变化情况。结果表明,活度系数不但与浓度有关,而且也与温度有关。     

高温高压下氯化钠水溶液的热力学(Ⅱ)——在823K及100MPa条件下NaCI-H_2O体系的热力学性质

本文将(I)报中提出的简易方程式推广应用到823K和100MPa的NaCl水溶液,NaCl的最高浓度达65.2wt%(三相点时的饱和溶解度)下热力学性质的计算.这些热力学性质包括溶液中水的活度、氯化钠的平均离子活度系数、溶液的Gibbs自由能,计算值与实验值吻合较好.文中列出了不同温度压力下的w和△_8G_2~0/RT值及其变化曲线、和本文提出的参考压力值P_r,为高温高压下电解质水溶液的研究作了初步的探索.     

用气液色谱法测定三元系中挥发组分有限浓度时活度系数的研究

本文研究了用色谱方法测定三元系中二个挥发组分在有限浓度时的活度系数,提出了实验规程及导出了用色谱数据计算活度系数的公式。测定了(1)苯-环己烷-邻苯二甲酸二壬酯(DNP)在40℃、60℃时,(2)苯-环己烷-角鲨烷(SQ)在60℃、80℃时二个体系中挥发组分(苯及环己烷)的活度系数。     

蛋氨酸在KCl溶液中的解离常数与活度系数

采用改变pH法在25、30和35℃下测定了质量浓度为0.25~4.0 mol/kg的KCl水溶液中蛋氨酸的解离常数,计算得到了蛋氨酸的质子化焓;采用电动势法在25℃测量了0.025~0.200 mol/kg蛋氨酸溶液中浓度为0.1~1 mol/kg的KCl的活度系数,计算得到了KCl溶液中蛋氨酸的活度系数。结果表明,蛋氨酸在KCl水溶液中的解离常数随温度上升而减小、随KCl浓度增加而增大;25℃下,蛋氨酸在KCl水溶液中的活度系数随蛋氨酸浓度增大先减小后增大。运用德拜-休克尔模型和Pitzer模型对解离常数和活度系数的实验数据进行拟合,得到了相关参数,结果表明Pitzer模型的可靠性较好。     

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.     

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.     

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。