掺Fe3+纳米TiO2晶体结构及光催化性能研究

采用溶胶-凝胶法制备了纯的和Fe3+掺杂的TiO2纳米粒子,对样品进行了XRD分析,并以甲基橙的光催化降解研究了样品的光催化性能.结果发现Fe3+的掺杂抑制了TiO2粒径的长大,细化了晶粒;Fe3+掺入到TiO2的晶格中,引起了晶格的畸变和膨胀;Fe3+的掺杂促进了TiO2由锐钛矿向金红石的转变;Fe3+的掺杂量和煅烧温度对其光催化性能影响较大,在本实验的条件下,Fe3+的最佳掺杂量为0.05%,最佳煅烧温度为600℃.     

Fe3+掺杂TiO2溶胶的低温制备及其光催化性能

采用溶胶-凝胶法在低温下制备出Fe3+掺杂TiO2(Fe3+/TiO2)溶胶,研究Fe3+掺杂对TiO2催化性能的影响,用TG/DTA技术分析TiO2粉末的热分解过程,用XRD、TEM等表征Fe3+掺杂对TiO2晶型、晶粒尺寸、晶粒形貌的影响,结果表明:Fe3+掺杂会对纳米TiO2晶粒的粒径及晶体形貌产生影响,抑制TiO2晶型由锐钛矿向金红石的转变。将亚甲基蓝作为目标污染物进行光催化降解试验,紫外-可见漫反射吸收光谱分析表明:经适量Fe3+掺杂后的TiO2溶胶光催化活性提高,当硝酸铁与钛酸丁酯的物质的量比为0.20%时,光催化活性最佳。     

La3+掺杂TiO2薄膜制备及其电致变色特性研究

基于提高TiO2薄膜的光学属性和着色效率,以钛酸四丁酯和氧化镧为主要原料,采用溶胶-凝胶法,在ITO玻璃表面制备La3+掺杂TiO2薄膜.通过XRD、SEM、EDS、TG-DTA等手段对制备La3+掺杂TiO2凝胶粉末进行表征,使用电化学工作站CHI660E和紫外-可见光分光光度计UV-5500PC对La3+掺杂TiO2薄膜的电致变色性能进行测试.结果表明:凝胶在加热的过程中发生一系列的物理和化学反应,且当温度升高至400 ℃时,系统达到相对热稳定状态.经600℃热处理,La3+掺杂TiO2转化为金红石相.外加电压为-2V时,薄膜显示为深蓝色,反向施压至+2V时,蓝色褪去.金红石相TiO2无定形程度随La3+掺入量增加而提高,对应其着色效率提高.La3掺杂TiO2薄膜在可见光范围内透过率均在70％ ～ 80％,光学性能良好.     

Pb2+掺杂TiO2的光催化性能研究

以钛酸丁酯和硝酸铅为原料,用溶胶-凝胶法制备了Pb2+掺杂纳米TiO2粉体,讨论了不同掺杂浓度、不同热处理温度样品在催化降解刚果红染料实验中的光催化活性,分析了Pb2+掺杂TiO2样品的相组成、晶胞参数和晶粒大小对光催化活性的影响.结果表明:Pb2+掺杂能够使锐钛矿向金红石的转变温度向高温方向移动,并且细化了晶粒,实验最佳掺杂浓度为100∶2.0,最佳热处理温度为700℃;Pb2+掺杂的TiO2的锐钛矿相是影响光催化活性的决定性因素.     

稀土Nd掺杂纳米TiO2的制备及光催化活性探讨

采用溶胶-凝胶法制备了稀土元素Nd掺杂的纳米TiO2光催化剂(Nd-TiO2).通过XRD、SEM、XPS等对Nd-TiO2样品进行了表征和分析,结果表明:稀土Nd掺杂抑制了纳米TiO2晶粒的生长,,提高纳米TiO2的热稳定性并阻碍其由锐钛矿相向金红石相的转变,在界面处形成的Ti-O-Nd键对纳米TiO2粉体的表面化学态和光催化性能产生影响.以甲基橙作为目标降解物,考察了掺杂量、煅烧温度、煅烧时间对催化剂光催化性能的影响,结果表明:当Nd掺杂量为3wt％,在550℃下煅烧4h时,TiO2的催化活性最佳,远远高于P-25的光催化效果.     

Fe3+/Zn2+复合掺杂纳米TiO2的结构及光催化性能

采用溶胶-凝胶工艺,以钛酸丁酯(Ti(C4H9O)4)为前驱体,冰醋酸为螯合剂,制备了Fe3 /Zn2 复合掺杂的改性纳米TiO2粉体材料.运用X射线衍射、透射电镜、X射线光电子能谱、Fourier变换红外光谱和光吸收研究了铁锌元素掺杂对纳米TiO2相变和光催化活性的影响.结果表明:铁及锌的掺杂会降低TiO2由锐铁矿相向金红石相的转变温度;掺铁和锌能提高纳米TiO2的光催化活性;当Fe3 /Ti4 摩尔比为0.2,Fe3 /Zn2 摩尔比为0.5时,经300℃焙烧1 h制备的Fe3 /Zn2 复合掺杂纳米TiO2样品的光催化活性最好;在太阳光照4h时,Fe3 /Zn2 摩尔比为0.5复合掺杂纳米TiO2样品对甲基橙的降解率可达71.43%.     

掺杂铁TiO_2纳米微粒的制备及光催化性能

以钛酸四丁酯为前驱体,采用溶胶-凝胶法制备了Fe3+掺杂改性纳米TiO2光催化剂,通过纯TiO2和掺铁TiO2分别做光催化剂时甲基橙溶液在紫外光下的光催化降解试验发现,掺杂铁离子可以有效提高TiO2的光催化活性,结果表明:选用Fe3+掺杂量为0.05%,煅烧温度在500℃下得到的Fe3+-TiO2催化剂,在甲基橙溶液pH值为3,催化剂投加量为1 g/L时,其光催化活性达到最佳效果。     

稀土掺杂对TiO2-SiO2薄膜晶相转变及性能的影响

采用溶胶-凝胶法在釉面砖上制备了均匀的稀土离子La3+掺杂和ce4+掺杂的TiO2-SiO2,光催化薄膜.应用X射线衍射(XRD)和紫外可见分光光度计研究了La3+掺杂和ce4+掺杂对TiO2-SiO2,薄膜晶相转变、光催化性能及亲水性能的影响,用紫外光照射亚甲基蓝的光催化降解实验比较了不同薄膜的光催化性能.结果表明:La3+掺杂后,抑制了TiO2-SiO2薄膜中的TiO2,从锐钛矿向金红石相的晶型转变,显著提高了TiO2-SiO2,薄膜的光催化性能,也提高了其亲水性能;ce4+掺杂后,则促进了TiO2-SiO2,薄膜中TiO2从锐钛矿向金红石相的晶型转变,同时降低了薄膜的光催化性能.     

铁和镧共掺杂二氧化钛的光催化活性

采用溶胶-凝胶法制备了纯的和铁镧共掺杂的TiO2纳米粒子,对样品进行了X射线和紫外-可见吸收光谱分析。结果表明,500℃煅烧的未掺杂和共掺杂TiO2均呈锐钛矿结构,铁镧共掺杂抑制了TiO2粒径的长大,使TiO2的吸收带边红移且在可见光区的光吸收增强;光催化降解甲基橙表明,未掺杂的TiO2光催化活性高于P25,而适量铁镧共掺杂TiO2光催化活性进一步得到提高,最佳掺杂比是0.05%的Fe和0.5%的La。     

煅烧温度对纳米TiO2光催化降解甲基橙性能的影响

以钛酸四正丁酯为原料,采用溶胶-凝胶法制备了不同煅烧温度(500℃、600℃、700℃和800℃)的TiO2纳米粒子,对样品进行了TG-DTA、XRD、UV-Vis及IR分析,并以甲基橙为目标降解物,考察了煅烧温度对TiO2光催化性能的影响.结果表明:随着煅烧温度的升高,TiO2晶粒尺寸迅速长大,800℃时,出现金红石相;TiO2的吸收带边随煅烧温度的升高发生了不同程度的红移;600℃煅烧得到的TiO2粒子表面易羟基化,其光催化性能最好.     

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.     

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。     

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.     

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.     

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.