含银纳米晶TiO2有序多孔膜层的制备及其光学性能

以单分散聚苯乙烯(PS)微球为原料,水为稀释溶剂,利用垂直沉降法制备出多层PS球有序阵列模板.采用溶胶-凝胶法制备TiO2溶胶,并用胶晶模板法制备出锐钛矿型TiO2有序多孔薄膜.然后将金属银纳米晶掺入多孔膜骨架中制备出含银纳米晶的TiO2有序多孔发光薄膜.分析了掺银的TiO2有序多孔膜的形貌与结构,并研究了掺银的TiO2有序多孔膜吸附罗丹明B及量子点CdSe荧光物质的荧光增强性能.结果表明:掺银的TiO2薄膜基本呈现多孔结构并保留有一定的有序性.有序多孔骨架中银纳米晶的表面荧光增强作用可大幅度提升荧光物质的荧光性能,从而扩展了TiO2有序多孔薄膜在生物信息探测、光信息处理领域的应用.     

TiO_2纳米晶和薄膜的制备及微观性质研究

以钛酸四丁酯为前驱体,采用溶胶-凝胶法制备了TiO2纳米晶和薄膜。分别用X射线衍射(XRD)和差热-热重分析(DTA-TGA)对不同温度热处理的样品进行了表征。XRD分析表明:经过热处理的样品,锐钛矿相TiO2纳米晶平均粒子尺寸为5 3～32 4nm,其薄膜的平均粒子尺寸为6 7～29 6nm,但经相同温度热处理的TiO2纳米晶平均粒子尺寸普遍较薄膜样品大,此外,TiO2薄膜的相转变温度比纳米晶约高150℃,且其锐钛矿相(101)面上具有一定的择优取向,取向因子为0 53;DTA-TGA结果表明,360～500℃,TiO2凝胶从非晶态-锐钛矿相的转变是逐渐转变的过程;实验所制备样品的比表面积可达72 57m2/g,呈现出巨大的表面效应;同时光生载流子能在极短的时间内(<20ps)跃迁到TiO2纳米颗粒表面,有利于电子和空穴的分离。     

低温液相法制备锐钛矿型TiO2纳米薄膜及其性能表征

采用低温液相法制备锐钛矿型TiO2纳米溶胶,用浸渍提拉法在玻片表面制备TiO2纳米薄膜.XRD表征结果显示60℃热处理后TiO2纳米粒子为锐钛矿晶型,SEM、TEM图谱显示其平均粒径10～20 nm,且具有良好的成膜性.制备的TiO2纳米薄膜具有光催化氧化脱色活性高、亲水性好、附着力强、耐蚀性好等特点.     

TiO2薄膜的低温制备以及工艺优化和性能研究

采用改进溶胶-凝胶法,通过浸渍-提拉工艺在载玻片表面低温制备了锐钛型纳米TiO2薄膜,探讨了水量、pH、水浴时间等工艺参数对TiO2的晶型及光催化活性的影响.利用XRD、FT - IR、SEM和UV - Vis光谱等手段对薄膜的物相、结构、表面形貌以及光吸收特性进行了表征,并利用紫外光激发下降解亚甲基蓝溶液来评价TiO2薄膜的光催化活性.结果表明:在低温条件下,所得TiO2薄膜表面均匀平整;随着水量的增加和pH的降低,TiO2晶化程度逐渐提高;水浴前后所制备的TiO2薄膜对紫外光都表现出了极强的吸收特性;水浴处理有利于提高纳米TiO2薄膜的催化活性,80 ℃水浴8h后TiO2薄膜对亚甲基蓝溶液的降解率从20.9％提高到72.1％.     

纳米二氧化钛薄膜的制备及性能研究

用溶胶-凝胶法在清洁的玻璃表面成功制备了均匀透明的纳米TiO2薄膜,并用X射线衍射仪,扫描电镜,红外光谱仪和接触角测定仪等对薄膜的结构和性质进行了研究.结果表明:薄膜由晶粒大小为20～45 nm的TiO2球型颗粒组成,膜表面均匀,结构致密,具有平整的组织结构;随热处理温度的增加,TiO2薄膜的晶相由无定型态转变成锐钛矿,最后在850℃热处理后完全转变成金红石相,且TiO2薄膜在经过紫外光的照射后亲水能力增强.     

超重力场中纳米TiO2粒子表面包覆Al2O3膜及其表征

基于异相表面成核和撞击流-旋转填料床反应器的微观混合原理,以纳米水合氧化钛(TiO2·nH2O)粒子为固相基体,六水氯化铝溶液为包覆相,采用液相包覆-界面反应的方法在纳米TiO2前体颗粒表面包覆了纳米Al2O3膜,并对超重力场中纳米粒子表面包覆过程进行了初步分析。通过IR、TEM、Zeta电位分析和XRD分析,证实了纳米TiO2前体颗粒表面包覆了一层厚约5nm的致密海绵状膜。IR和XRD谱图表明,在Al2O3纳米膜层和纳米TiO2颗粒之间的界面上形成了Ti—O—Al键,包覆膜层的晶体结构以γ-Al2O3为主的混合晶型。     

（Ni–Mo）/TiO2纳米薄膜光电催化降解罗丹明B的性能

采用恒电流复合电沉积制备了（Ni–Mo）/TiO2薄膜,对薄膜的表面形貌、晶相结构和光谱特性进行了表征,以罗丹明B为模拟污染物对薄膜的光电催化性能进行了测定,并分析了光电催化机理。结果表明：（Ni–Mo）/TiO2薄膜是粒径为50～100 nm的TiO2纳米粒子相和纳米晶Ni–Mo固溶体相构成的复合薄膜。薄膜具有优异的...     

TiO2/In2S3复合薄膜的制备及光电化学性能研究

首先采用水热法在FTO(SnO2:F)透明导电玻璃衬底上合成TiO2纳米片阵列,继而在TiO2纳米片表面水热制备In2 S3纳米颗粒形成TiO2/In2 S3复合薄膜.通过X射线衍射仪(XRD)、X射线能谱仪(EDX)、扫描电子显微镜(SEM)和紫外-可见光吸收谱以及三电极光电化学测试系统对复合薄膜的晶相、微观形貌、光学性能和光电性能进行了表征和分析.结果表明,随着In2 S3水热生长时间的延长,复合薄膜的光吸收性能逐步延伸到可见光区域.光电化学(PEC)测试结果表明光照条件下,TiO2/In2S3复合薄膜的电流显著提高,是TiO2纳米片阵列电流的4.2倍.     

纳米晶TiO2多孔薄膜的研究进展

综述了近年来纳米晶TiO2多孔薄膜材料的研究进展情况,对纳米晶TiO2多孔薄膜材料的各种制备方法及其特点进行了归纳和分析,并时纳米晶TiO2多孔薄膜材料的应用现状作了简要介绍.     

TiO2/SiO2复合薄膜的晶型和晶粒尺寸研究

通过溶胶－凝胶工艺在普通钠钙玻璃表面制备了均匀透明的TiO2/SiO2复合薄膜，由紫外可见光谱发现：在TiO2薄膜中添加SiO2后，薄膜中TiO2晶粒尺寸变小，TiO2/SiO2复合薄膜的吸收边缘波长发生了明显的“蓝移”。进一步用X射线衍射（XRD）和透射电镜（TEM）表征了TiO2/SiO2复合粉末和TiO2粉末的晶型和晶粒尺寸，结果发现，在TiO2凝胶粉末中添加少量SiO2（如摩尔分数为5％）后，TiO2和晶粒生长受到明显抑制，晶粒尺寸明显变小，为6－7nm；当TiO2凝胶粉末中添加的SiO2量较高时，随热处理温度升高，TiO2的晶型转变和晶粒生长受到更大抑制，晶型转变的晶粒生长更缓慢。     

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.     

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。     

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.     

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.