溶剂热法可控合成纳米氯化亚铜

以氯化铜为铜源,甲醇、乙醇、异丙醇等为溶剂和还原剂,采用溶剂热法制备纳米氯化亚铜,探讨了温度、时间、还原剂等条件对所得氯化亚铜的形貌、粒径大小、物相组成的影响。结果表明,以乙醇、异丙醇为溶剂,在120~180℃反应24~48 h,Cu Cl纳米颗粒可在2~50 nm范围内有效调控。     

吐温和十二烷基硫酸钠复配修饰制备纳米铜研究

在一定温度的水溶液中,以硫酸铜为前驱体,抗坏皿酸（Vc）为还原剂,加入适量修饰剂,合成粒径和形貌可控的纯铜纳米粒子,并通过XRD射线衍射,扫描探针显微镜等检测手段对产品进行了表征。结果表明,修饰剂的加入对粒径大小、分布、形貌和晶型结构影响显著;制备的纳米铜颗粒为具有立方品型结构的球型颗粒,分散性较好,尺寸较为均匀,约为60～80nm。纳米铜颗粒表面形成了较薄的有机物质包覆层,它有效阻止了纳米铜粉在空气和水中的氧化和团聚,提高了纳米铜颗粒的分散性和稳定性。     

撞击流反应器制备纳米铜粉的研究

在浸没循环撞击流反应器(SCISR)中,采用五水硫酸铜为原料,以硼氢化钾为还原剂制备纳米铜粉。确定了制备纳米铜粉的适宜工艺条件是:Cu2+的浓度为0.2 mol/L,硼氢化钾与硫酸铜物质的量比为1∶1,氢氧化钾与硼氢化钾物质的量比为9∶1,反应温度为40℃,反应时间为10 min,2%(质量分数)聚乙烯吡咯烷酮用量为80 mL。采用TEM和XRD对产品进行表征。所得产品呈近似球形,直径20³0 nm;纯度高,其收率高于98%。     

均匀沉淀法制备不同粒径的纳米Cu（OH）2

以无水硫酸铜和氢氧化钡为原料,采用均匀沉淀法研究了不同粒径纳米Cu（OH）2的制备,考察了搅拌温度、硫酸铜溶液浓度等反应条件对纳米Cu（OH）2粒径的影响。实验结果表明,用均匀沉淀法可以制备出不同粒度的纳米Cu（OH）2颗粒。反应条件对纳米Cu（OH）2的粒径有显著影响,反应温度越高,纳米粒子的粒径越小;硫酸铜溶液的浓度越高,纳米粒子的粒径越大。     

硼氢化钠还原氯钯酸制备纳米钯

用三缩四乙二醇作溶剂,用硼氢化钠还原氯钯酸的方法制备了溶剂稳定的钯金属纳米颗粒,得到了分布均匀、平均粒径在1.35 nm的钯金属纳米颗粒。同时讨论了得到小颗粒的钯金属纳米颗粒的最佳条件。     

用于化学复合镀的Ni3.1B非晶态纳米合金粉体的制备

利用化学还原法,以硼氢化钾为还原剂,制备了Ni3.1B非晶态纳米合金粉末,用于化学镀(Ni-P)-Ni3.1B合金镀层。通过对还原剂硼氢化钾、稳定剂硫脲和表面活性剂聚乙烯吡咯烷酮对Ni3.1B纳米合金粉末的粒径的影响,确定化学还原法制备Ni3.1B的最佳条件为0.02 mol/L NiCl2.6H2O,0.06 g/L KBH4,2mg/L硫脲,0.25g/L聚乙烯吡咯烷酮。通过对Ni3.1B粉体分散性和在化学镀Ni-P-B合金镀液中的稳定性的研究,发现海藻酸钠对Ni3.1B具有良好的包覆效果。     

基于不同还原体系铜纳米颗粒的可控制备及其对梨火疫病菌的抗菌性能

[目的]明确3种不同还原体系下制备的铜纳米颗粒对梨火疫病菌(Erwinia amylovora)的抑制效果。[方法]以乙酸铜为铜前驱体,水合肼、L-抗坏血酸、葡萄糖为还原剂,聚乙烯吡咯烷酮(PVP)为模板,利用原位还原法制备纳米铜颗粒。通过扫描电子显微镜(SEM)、傅里叶红外光谱仪(FTIR)和牛津能谱仪(EDS)对其结构进行表征,采用生长速率法和田间药效试验测定其对梨火疫病菌的生物活性。[结果]乙酸铜在3种不同还原剂作用下均制备出了纳米铜颗粒,其中由水合肼还原的纳米铜颗粒平均粒径最小[(130±7) nm]且铜含量最高(83.35%),对E. amylovora的抗菌效果最好,并且对大白菜未出现药害现象。[结论]由水合肼还原的纳米铜颗粒具有理想的抗菌活性和植物安全性,对防治梨火疫病菌具有较好的应用前景。     

纳米硫酸钡的制备及表征

以硫酸钠和碳酸钡为原料,碳酸钡经过浆化处理后,与硫酸钠直接反应制备纳米硫酸钡。实验考察了浆化溶剂用量对纳米硫酸钡粒度的影响,随着浆化溶剂用量的增加,纳米硫酸钡的产率提高,颗粒分布更均匀,粒径更小。经SEM和XRD测试分析,计算得出粒子的平均粒径为20nm左右。结果表明,该法可以制备出粒径小、分布窄的纳米硫酸钡粒子。     

溶剂稳定的钯纳米颗粒的控制合成

以乙酸钯为前体、三缩四乙二醇为溶剂和还原剂,在不使用保护剂、适量无水乙酸钠存在下,60℃水浴加热4 min,乙酸钯还原得到溶剂稳定的粒径小、大小均一、分散性好的钯纳米颗粒,平均粒径为(3.51±0.49)nm。     

纳米金溶胶的合成及紫外-可见吸收光谱的研究

在弱酸性或近中性条件下,用化学还原剂还原较高浓度的氯金酸溶液,制得纳米金种子溶液,然后用晶种法制备金溶胶。通过透射电镜、激光粒度分布仪等测定了纳米颗粒的粒径和分布情况,并对纳米金溶胶的紫外可见吸收曲线进行了研究。结果表明,以硼氢化钠为还原剂可以得到粒径小且分布均匀的产品,采用不同大小的晶种制备的纳米金颗粒的粒径不同,且随粒径变大紫外-可见吸收曲线上的最大吸收波长红移也越大,分布变宽。     

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.     

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.     

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.     

Novel polyurethane coating technology through glycidyl carbamate chemistry

Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.