化学共沉淀法合成ZrO2-8wt%Y2O3纳米粉体相转变及晶粒生长行为研究

以ZrOCl₂·8H₂O和Y(NO₃)₃ ·6H₂O为原料，采用共沉淀法合成纳米ZrO₂-8wt%Y₂O₂（8YSZ）陶瓷粉末。利用XRD,SEM,TEM等方法研究纳米8YSZ粉末热处理后相结构、晶粒尺寸和形貌的变化，并分析纳米8YSZ粉末的晶体生长行为。结果表明：凝胶化反应的pH值（9~11）对纳米8YSZ粉末的相结构无明显影响，不同pH值合成的8YSZ纳米粉末在1000℃温度范围内热处理2h后都始终保持单一的四方相结构，在1200℃热处理2h后，仅有少量四方相转变为单斜相。随热处理温度的升高晶粒尺寸逐渐增大。由于晶体生长机制不同，纳米8YSZ粉末的晶粒生长活化能在低温区和高温区不同，均远低于微米级3YSZ材料的晶粒生长活化能（580kJ/mol）。     

以煤基工业废料为原料固相法合成小粒径圆形A型沸石分子筛

首次以煤基工业废料为原料为固相法（H2O和Na2O的摩尔比低于0．9），合成了具有圆形晶粒形貌的小晶粒（1um)A型沸石分子筛，其各项质量指标符合行业标准，并对合成的条件及机理进行讨论，提供了固相转化机理在低硅类沸石合成领域的实验佐证，并为大宗煤工业废渣的综合治理及深层次开发利用提供基础性数据。     

水热合成NaNbO3粉体的研究

采用Nb2O5,NaOH为反应原料,在180℃～200℃下通过水热法合成出结晶度高、晶粒发育完整的NaNbO3粉体。利用X射线衍射分析（XRD）对产物的物相结构进行了表征,并用扫描电子显微镜（SEM）观察了晶粒的结晶形貌、尺寸以及分布情况。研究结果表明：合成的NaNbO3粉体为正交相结构,晶胞参数a=5.569,b=15.523,c=5.505;水热合成温度影响体系的反应速度,温度越高反应速度越快;晶粒的尺寸随着反应时间的增加而增大。     

以聚苯乙烯磺酸钠为模板合成球状羟基磷灰石

以Ca（NO3）2·4H2O和（NH4）3PO4·3H2O为原料,聚苯乙烯磺酸钠（PSS）为模板,采用生物矿化法成功地合成球状纳米羟基磷灰石（HA）,研究了不同浓度的PSS对HA形貌的影响,并推测了球状HA的形成机理。采用X射线衍射（XRD）、傅立叶变换红外光谱仪（FTIR）、透射电镜（TEM）、热分析（TG—DSC）对产物化学组成、晶相结构及晶体形貌等进行了表征,结果表明,PSS对HA的形貌有很大影响,当质量分数为0．5％时,得到分散均匀,粒径在15nm左右的HA晶粒。     

Effect of pH Value on Morphology of MnWO4 Microcrystallites Prepared by Microwave Hydrothermal Method

以四水氯化锰（MnCl2 4H2O）和二水钨酸钠（Na2WO4 2H2O）为原料，采用微波水热法在不同 pH 值下成功制备了 MnWO4微晶。利用 X 射线衍射和透射电子显微镜分别对产物的物相和形貌进行了表征；并对棒状 MnWO4微晶的形成机理进行了初步探讨。结果表明：在 pH 为 4.0～11.0 范围内均可制备出纯相的 MnWO4晶体，随着 pH 值的增大，产物的结晶性有所提高，晶粒尺寸逐渐增大，同时其形貌由粒状向棒状转变。     

铌酸钾钙无铅压电陶瓷粉体的水热法制备

以KOH,Ca（OH）2和Nb2O5为原料,通过水热法合成了钙钛矿结构的（Ca,K）NbO3粉体。借助X射线衍射仪（XRD）对产物晶体结构进行表征,通过能量色散X射线荧光法（EDX）分析产物的化学组成,用扫描电子显微镜（SEM）观察产物粉体的表观形貌和粒径。研究了反应时间对产物形貌和晶体结构的影响。结果表明,在200℃,48h,浓度为6mol/L的碱性溶液条件下,可以合成出长2.0μm,宽0.2μm的长条状形貌的钙钛矿结构（Ca,K）NbO3粉体,此粉体有望用作钨青铜结构Ca2KNb5O15织构陶瓷的模板晶粒。     

溶胶-凝胶法掺杂合成α-Fe2O3纳米粉体

采用溶胶-凝胶法制得不同掺杂氧化物（W=5％）的α-Fe2O3纳米粉体材料，利用透射电子显微镜对粉体的粒径和形貌进行了观测；利用XRD对产品的物相进行了．分析，结合谢乐公式对晶体原始尺寸和晶胞进行了计算；对产品的干凝胶原粉做了TG—DTA分析以研究其热稳定性和相变温度。结果表明：合成的产物颗粒呈圆球形，粒径细小。其中掺杂Eu2O3和Y2O3合成的α-Fe2O3纳米粉体粒径较小，仅为22nm和25nm。     

碳热还原法合成硼化锆粉体影响因素探究

以氧化锆(ZrO2)、硼酸(H3 BO3)和碳(C)粉为原料,研究了不同碳粉(活性炭、石墨)与前驱体粒度、温度及保温时间对碳热还原法制备硼化锆(ZrB2)粉体的影响.通过X射线衍射(XRD)分析合成粉体物相,扫描电镜(SEM)观察合成粉体形貌,并通过化学方法分析了合成粉体中的C、O含量.结果表明:以活性炭为碳源合成的粉体形貌呈条棒状,以石墨为碳源合成的粉体形貌呈规则的块状;合成粉体的粒度随前驱体粒度减小而减小,形貌由规则的块状逐渐转变为圆滑的不规则形貌,合成ZrB2粉体最小平均粒度约为1.69μm,产物中C含量随前驱体粒度减小而减少,O含量随前驱体粒度减小而增加,氧含量最低为0.54wt％;碳热还原法合成ZrB2粉体在1500℃下是可行的,但直到1900℃碳热还原反应合成ZrB2才进行完全;碳热还原反应合成ZrB2粉体最佳的反应条件为1900℃保温30 min.     

以四氯化硅水热法合成高纯微米级石英晶体

采用水热法,以多晶硅副产物四氯化硅为原料,碳酸钠为矿化剂,研究了不同温度下石英晶体的合成。并利用X射线衍射仪（XRD）、扫描电镜（SEM）和能谱仪（EDS）对其物相结构、形貌和成分进行了表征。结果表明,合成的石英晶体为典型的低温α-石英,呈棱柱状轴向生长;随着温度的升高,晶粒尺寸逐渐增大,在220 ℃下制备得到的晶粒最大,平均粒径为8 μm左右;但当温度为230 ℃时,制备的石英晶体的晶粒反而变小。     

水热法生长Mg（OH）_2晶体研究

以MgCl2.6H2O、NH3.H2O为原料,水作为水热介质,乙二醇作为表面活性剂,研究了在不同温度条件及表面活性剂用量对水热法生长Mg（OH）2晶体的影响。利用X-射线衍射仪（XRD）和扫描电子显微镜（SEM）对所制得氢氧化镁颗粒的晶相和形貌进行了表征。实验结果表明,增加乙二醇的用量,有助于获得结晶性和分散性较好的Mg（OH）2晶体。同时,随着生长温度的升高,Mg（OH）2晶体形貌从球状外形的片状晶体向分散的小晶粒过渡。     

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.