纳米CeO2的微波制备工艺研究

以Ce(SO4)2.4H2O和NaOH为原料,聚乙二醇(PEG)为表面活性剂,在微波作用下制备纳米CeO2。通过考察制备过程中的各个影响因素,得出了制备纳米CeO2的最佳工艺条件:n(NaOH)∶n[Ce(SO4)2]=4.8∶1,PEG的反应用量为8 mL,PEG的洗涤用量为7 mL,无水乙醇的洗涤用量为10mL,微波恒压时间为6 min,微波压力为0.14 MPa,微波功率为232 W,超声波分散时间为10 min,微波干燥时间为10 min,在最优化工艺条件下制备的CeO2的粒径为24.9 nm。     

反相单微乳液法制备纳米二氧化铈及其形貌和分散性研究

以六水硝酸铈和氨水为原料,使用单微乳型,在烷基酚聚氧乙烯(10)醚(OP-10)/正丁醇/环己烷/水溶液组成的水/油型微乳液体系中,制备了纳米二氧化铈微粒.利用XRD,TG-DSC,TEM,UV-VIS等对样品进行表征.TEM表明:体系环己烷含量主要影响产物纳米二氧化铈微粒的分散性;体系中水与OP-10的物质的量比和反应温度对产物微粒的形貌影响显著.当反应温度为25 ℃,环己烷占3个有机组分的质量分数为60%、水与OP-10的物质的量比为15时,可制备出分散性好的球形纳米二氧化铈微粒,粒径约4 nm.硅烷偶联剂A-1120的表面修饰更加显著地提高了纳米颗粒的分散性.UV-VIS表明:纳米二氧化铈具有优异的紫外吸收性能.     

化学共沉淀法制备纳米四氧化三铁粉体

采用化学共沉淀法制备纳米Fe3O4粉体,并用聚乙二醇表面活性剂进行表面改性,在铁离子浓度比Fe2＋：Fe3＋=1：2时,对制备工艺影响因素进行了讨论。通过实验得到的最佳工艺条件为：控制温度介于40～60℃,最佳的pH取值为9,聚乙二醇的适宜用量取5～10 mL。采用TEM观测制备的纳米Fe3O4颗粒的形貌及其大小,得到的纳米Fe3O4颗粒粒径为20～50 nm之间。     

微波固相合成纳米铜锰复合氧化物及表征

采用室温微波固相合成法制备了纳米级铜锰复合氧化物，微波加热大大缩短了传统低温固相热分解的时间；用XRD谱、TEM和IR等测试手段对前驱物和产物的物相及微观结构进行了表征，找出了影响微波固相合成铜锰复合氧化物的主要因素。在微波辐射功率为540W、微波辐射时间为10min、热分解温度为350℃、分解时间为2h的条件下制备铜锰复合纳米氧化物，测试结果表明，其产物属立方晶型，粒径主要在20～50nm范围。     

碳纳米管负载二氧化铈纳米粒子的研究

通过在液相沉淀反应中直接加入碳纳米管作为沉淀承载基体制备了碳纳米管负载的二氧化铈纳米颗粒。电镜分析证实了在碳管的表面高密度地均匀沉积了多层粒径为4～6nm的二氧化铈粒子,也有部分二氧化铈粒子填充进入碳管的内腔,形成了二氧化铈,多壁碳管复合材料,所获得的纳米复合材料可望成为一种新型的高效催化剂,在催化领域特别是车辆尾气处理上有潜在应用。     

水菱镁矿制备高分散六角片状纳米氢氧化镁的新工艺条件探究

以水菱镁矿为原料,通过“煅烧-水化-煅烧-水热”的简单合成路线制备了高分散六角片状的阻燃型纳米氢氧化镁。确定初步工艺后,探究了氧化镁用量、水热温度和水热时间对氢氧化镁结晶度和形貌的影响,确定最佳工艺水热条件：氧化镁用量为10%~25%（质量分数）、水热温度为150 ℃、水热时间为3 h。在水热过程中,分别向反应体系中加入聚乙烯吡咯烷酮（PVP）、十六烷基三甲基溴化铵（CTAB）、聚乙二醇6000（PEG6000）和聚乙二醇200（PEG200）,考察了不同改性剂及改性剂用量对氢氧化镁颗粒结晶度和分散性的影响。结果表明在4%（质量分数）PVP的条件下,能很好地改善纳米氢氧化镁的分散性,并得到了分散性好、晶形完整、粒径均匀、直径为300~400 nm、厚度为40~60 nm的六角片状纳米氢氧化镁。     

纳米氧化高银分散液的制备

运用液相氧化沉淀法制备了纳米级复合氧化高银分散液.探讨了温度、氧化剂用量、过饱和度、分散剂用量以及末期反应时间对分散液颗粒粒径大小和纯度的影响.得到了产品的最佳制备工艺:采用非离子聚乙烯型DJ2004为分散稳定剂、反应温度60℃、DJ200/AgNO3=0.4、K2S2O8/AgNO3=10、末期反应时间-10min、C(AgNO3)=0.18～0.25mol/L.制备出粉体粒径为20～100nm、含氧化高银70%的纳米氧化高银分散液.     

白云石制备的纳米氢氧化镁的性能及其影响因素

探讨了白云石碳化法制备纳米级氢氧化镁的工艺条件,研究了沉淀剂、反应温度对纳米级氢氧化镁形貌的影响,以及表面活性剂对纳米级氢氧化镁分散性的改善,并对反应机理进行了阐述.结果表明:以氨水为沉淀剂所得的纳米氢氧化镁近似六边形的薄片状,平均粒径为16nm,其结构稳定性优于以氢氧化钠为沉淀剂的产品.当反应温度为30℃时,Mg(OH)_2形成细小晶核,薄片的厚度为5～7nm,晶粒粒径为10～15nm;反应温度为50℃时,晶核开始生长为大晶粒,但排列无规则;反应温度为70℃时,Mg(OH)_2薄片的厚度增至10nm左右,晶粒粒径为10～20nm,具有规则排列的完整晶粒:反应温度为80℃时,Mg(OH)_2晶粒具有不规则排列.加入表面活性剂聚乙二醇或十二烷基硫酸钠可以提高纳米粒子的分散性.当表面活性剂聚乙二醇用量为氢氧化镁的3.0%(以质量计,下同)时,纳米氢氧化镁的分散性最好,片层的厚度约为10 nm,平均粒径为20 nm.当表面活性剂十二烷基硫酸钠用量为氢氧化镁的4.0%时,纳米氢氧化镁具有较好的分散效果,平均粒径为20nm.     

细乳液聚合纳米乳胶荧光颜料的制备

采用细乳液聚合法制备了纳米乳胶荧光颜料,研究了溶剂黄43用量,乳化剂、助乳化剂种类和用量,引发剂用量和超声波处理时间对纳米乳胶荧光颜料性能的影响。结果表明,纳米乳胶荧光颜料较佳的制备工艺为:溶剂黄43、十六烷(HD)和过硫酸铵(APS)的质量分数分别为1.5%、1.5%和0.8%(以单体质量计),乳化剂1-烯丙氧基-3-(4-壬基苯酚)-2-丙醇聚氧乙烯(10)醚硫酸铵(DNS-86)用量为0.019 11 mol/L,超声波处理时间9 min,在该条件下制备的纳米乳胶荧光颜料的粒径为162.1 nm,具有较高的耐热和离心稳定性,纳米乳胶荧光颜料的最大荧光发射波长517 nm,最大吸收波长425 nm。     

利用细乳液聚合由溶剂黄43制备纳米乳胶荧光颜料

采用细乳液聚合法制备了纳米乳胶荧光颜料,研究了溶剂黄43用量,乳化剂、助乳化剂种类和用量,引发剂用量和超声波处理时间对纳米乳胶荧光颜料性能的影响。结果表明,纳米乳胶荧光颜料较佳的制备工艺为:溶剂黄43、十六烷(HD)和过硫酸铵(APS)的质量分数分别为1.5%、1.5%和0.8%(以单体质量计),乳化剂1-烯丙氧基-3-(4-壬基苯酚)-2-丙醇聚氧乙烯(10)醚硫酸铵(DNS-86)用量为0.019 11 mol/L,超声波处理时间9 min,在该条件下制备的纳米乳胶荧光颜料的粒径为162.1 nm,具有较高的耐热和离心稳定性,纳米乳胶荧光颜料的最大荧光发射波长517 nm,最大吸收波长425 nm。     

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。     

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.