球磨对碳热还原氮化法制备氮化铝粉末的作用

研究了高能球磨对氧化铝碳热还原反应制备氮化铝的作用。结果表明：氧化铝及没料经高能球磨后,碳热还原反应开始温度降低,完全反应的温度降至1250℃。与未经球磨的反应相比,反应进行程度提高。球磨产生的机械化学作用,如细化晶粒、晶格畸变和大量缺陷及表面断健作用是球磨促进碳热还原反应的主要原因。     

铝试剂热氧降解动力学研究

本文在用热分析方法研究了铝试剂的热氧降解历程后＾［１］,用Ｃｏａｔｓ－Ｒｅｄｆｒｎ方程进行动力学处理,确定铝试剂热氧降解的表面反应级数为１．８、１．６、１．５、０．８２和活化能力６０．２ｋＪ／ｍｏｌ、１１３．３ｋＪ／ｍｏｌ、６５．２ｋＪ／ｍｏｌ、２７４．２ｋＪ／ｍｏｌ。     

碳热还原反应法合成氮化铝的研究

本实验采用碳热还原反应法合成氮化铝纤维,得到与氧化铝不同形貌的氮化铝。这与以前实验结果不同。本实验认为氮化铝碳热还原反应过程可以分为气—固两步进行,即当氧化铝与氮气和活性碳充分接触时,氧化铝在活性碳的作用下被还原成铝的低价氧化物并进一步氮化;而当氧化铝被第一步反应生成的氮化铝包裹严密不能与氮气和活性碳充分接触时,反应通过固相扩散来进一步完成,在固相扩散过程中,既包括了活性碳和氮气的扩散,也包括了铝离子的扩散,反应是在氮化铝层两个界面同时进行。     

Al2O3-C-N2系统反应热力学初步探讨

通过热力学计算 ,研究了高温下流动氮气床中碳热还原氧化铝反应过程 ,提出了其反应机理为气 固反应机制 ,很好地解释了在碳热还原法合成氮化铝过程中存在的现象。     

Al2O3—C—N2系统反应热力学初步探讨

通过热力学计算，研究了高温下流动氮气床中碳热还原氧化铝反应过程，提出了其反应机理为气－固反应机制，很好地解释了在碳热还原法合成氮化铝过程中存在的现象。     

高氮压法制备氮化铝粉

对在加压氮气中金属铝粉的直接氮化和氧化铝粉的碳热还原氮化法制备氮化铝粉末进行了研究。研究结果表明：铝粉在高温高氮压下快速氮化，生成氮化铝，其临界温度为７００℃，氮气的临界压力为１ＭＰａ；在高氮压下，氧化铝可通过碳热还原氮化法生成氮化铝，其含氮量与保温温度，氮气压力和保温时间有关；在高氮压下，碳热还原氮化法制备氮化铝，可使用铝粉为晶种，能获得高质量的氮化铝（Ｎ〉３３％，Ｏ〈１％，按质量计）粉末。     

用吲哚抑制曝露在空气中的0.5mol/L硫酸对铜的腐蚀

在２５℃～５５℃时,用动电位曲线法、失重法和分析法研究了曝露在空气中的０．５ｍｏｌ／Ｌ硫酸含不同浓度的吲哚对铜的腐蚀抑制作用。吲哚使腐蚀电势向更大值（即对铜溶解反应比阴极氧化还原反应有更强影响）方向移动。吲哚很可能通过与铜离子铬合对腐蚀反应机理产生影响。在２５℃、３５℃、４５℃时,吲哚的吸附作用遵循Ｆｒｕｍｋｉｎ等温线,在５５℃时遵循Ｌａｎｇｍｕｉｒ等温线。标准的吸附自由能分别为－２１．６ｋＪ／ｍｏｌ、－１８．３ｋＪ／ｍｏｌ、－２２．１ｋＪ／ｍｏｌ和－２７．９ｋＪ／ｍｏｌ。ＣＡ．１２９：１５１９…     

八甲基环甲硅氧烷聚合动力学

以四甲基氢氧化铵为催化剂,用蒸汽压法研究了八甲基环四硅氧烷的聚合动力学,获得了７７￣１１０℃间的聚合速率常数,并计算出反应活化能力１０３．０ｋＪ／ｍｏｌ。     

四氢萘加氢裂化反应动力学

在连续流动的微反装置上,研究了四氢萘加氢裂化反应动力学,探讨了加氢裂化催化剂活性中心与反应表观活化能的关系。结果表明,四氢萘加氢裂化反应为拟一级反应。在８．５ＭＰａ时,其表观活化能为１３２．７４８ｋＪ·ｍｏｌ－１。在６．５ＭＰａ时,当反应温度高于３６０℃,强酸中心与弱酸中心同时活化,活化能从８７．２７４ｋＪ·ｍｏｌ－１提高到１０３．２７６ｋＪ·ｍｏｌ－１     

乙酸异戊酯杂多酸催化合成及其动力学研究

研究了以钨硅酸为催化剂,苯为带水剂乙酸和异戊醇直接酯化合成乙酸异戊酯的优化反应条件,该杂多酸催化反应的速率方程为－ｄＣＡ／ｄｔ＝ｋＡｃＡｃＢ,反应表现活化能Ｅａ＝１４２．５７ｋＪ／ｍｏｌ,反应速率常数ｋＡ（Ｌ·ｍｏｌ＾－１·ｍｉｎ＾－１）＝７．７５×１０＾１７ｅｘｐ（－１７１４８．２／Ｔ）。     

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.     

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.     

基于ATRP法制备的触角状亲水性羟胺树脂的吸硼性能的研究

以大分子引发剂氯乙酰化聚苯乙烯微球(PS-acyl-Cl)经原子转移自由基聚合(ATRP)法引发丙烯酰胺(AM)和甲基丙烯酸缩水甘油酯(GMA)单体的共聚接枝,制得一种触角状亲水性环氧载体(PS-acyl-g-P(AM-co-GMA)),再经二乙醇胺(DEA)的环氧基开环胺化反应,得到一种含多个-NCH2CH2OH螯合配基的多齿-五元螯合环的触角状亲水性羟胺树脂(PS-acyl-g-P(AM-co-GMA)-DEA)。将此树脂用于硼吸附研究,结果表明,PS-acyl-g-P(AM-co-GMA)-DEA树脂对硼的吸附满足Langmuir方程,为单分子层吸附;饱和吸附量约为37.7 mg·g-1,且树脂5 min即可达到吸附平衡,与其它已报道的吸硼树脂相比,该树脂具有更高的吸附量和吸硼速率。吸附动力学研究表明,树脂吸附硼的过程主要由颗粒扩散过程控制。重复使用5次后该树脂的吸附量基本不变,解吸率均在90%以上,重复使用性能良好。