铜/钨酸锆功能梯度薄膜的热应力场特征有限元分析

用有限元法建立了铜/钨酸锆缓和热应力功能梯度薄膜的数学模型,讨论了梯度薄膜的层数N,成分分布指数P,梯度层厚度Hf,基片厚度Hm与纯铜层厚度Hc,以及不同工作环境温度θ对薄膜热应力分布的影响。由热力学计算可知:梯度层数越多,缓和热应力效果越好。考虑到制备工艺复杂程度,参考数值模拟结果可知:当N≥5,P=1时,可以减小热应力最大值,热应力最大值出现在基体与梯度层的界面处;当N=5,2≤P≤3,热应力最大值位于梯度层内;适量增加梯度层厚度Hf和基片厚度Hm有利于减小热应力最大值,此梯度缓冲层在室温到α相钨酸锆陶瓷的相变温度(120℃)区间内,对于各厚度的功能铜层都有良好的保护作用。     

磁控溅射法制备钨酸锆薄膜

在不同的气氛下,利用射频磁控溅射法在石英基片和硅片上制备了ZrW2O8薄膜.利用台阶仪和划痕仪测量了溅射薄膜的厚度和结合力,利用X射线衍射及原子力显微镜对薄膜的物相和表面形貌进行了分析和观察.初步研究了沉积条件对生长薄膜的厚度、附着力、相成分和表面形貌等的影响.结果表明:纯氩气下溅射的ZrW2O8薄膜最厚,膜基结合力随膜厚的增加而减小,溅射所得薄膜为非晶态,热处理后薄膜中出现了钨酸锆相,薄膜的表面形貌随气压的降低变得光滑.     

不同层Cu/ZrW2O8梯度薄膜的制备和性能

采用ZrO2、WO3复合氧化物和Cu靶材,利用磁控溅射法,通过改变溅射功率在单晶硅基片上分别制备1、3、5层Cu/ZrW2O8复合薄膜.通过X射线衍射、扫描电镜和原子力显微镜表征不同层薄膜的物相组成和表面形貌:采用划痕仪和应力测试仪分别测量薄膜的结合力和热应力.结果表明:未退火处理的薄膜为非晶态钨酸锆和铜的复合薄膜:在...     

WO_3-SiO_2复合薄膜的烧结温度–相组成–气敏特性关系

以钨酸和正硅酸乙酯(tetraethyl orthosilicate,TEOS)为原料,采用改进的溶胶–凝胶工艺,在Al2O3基底上制备WO3–SiO2复合薄膜,重点考查复合薄膜的烧结温度、物相组成及气敏性三者之间关系。用X射线粉末衍射仪和场发射扫描电子显微镜表征复合薄膜的微观结构,结果表明:在烧结温度为500℃与650℃时,复合薄膜为立方相和正交相混合相,复合薄膜的晶粒尺寸为25～30nm,分布均匀。650℃烧结时,对还原性挥发性有机化合物(volatileorganiccompounds,VOCs)气体中丙酮具有较好的敏感性。750℃烧结时,复合薄膜只有单一的正交相,晶粒尺寸在30nm左右,此时复合薄膜对氧化性气体NO2具有很好的敏感性与选择性,最低响应浓度(体积)为10–7,响应时间为2s,恢复时间约为10s。     

钨酸锆薄膜样品高温衍射测试方法

基于不对称布拉格反射理论,以平行光掠入射方式配合普通X射线粉末衍射仪的高温样品台,研究了玻璃基钨酸锆薄膜样品的高温衍射测试方法,与聚焦光方式相比,减弱了玻璃基体的噪音影响,增加了衍射峰的强度,提高了谱图的可读性.XRD数据表明：钨酸锆薄膜样品的晶格常数随温度升高而变小,从25℃时的0.91791 nm逐步变小至600℃时的0.91243 nm.     

CuO/ZnO叠层复合薄膜的制备及其光催化活性

分别通过光还原和电还原在以氧化铟锡玻璃为基体的ZnO上沉积Cu和Cu2O,后经400℃空气中热处理,制备了两种CuO/ZnO叠层复合薄膜。用X射线衍射、扫描电子显微镜和X射线能量散射谱分别对复合薄膜的晶相、形貌和化学组成进行表征。以橙黄II在模拟自然光照射下的光催化降解作为探针反应评价其光催化活性。结果表明：由Cu/ZnO经400℃下焙烧1h转化的CuO/ZnO叠层复合薄膜具有更高的光催化活性,反应1h后,橙黄II的降解率比由Cu2O/ZnO经400℃下焙烧1h转化的CuO/ZnO提高了14%。对CuO/ZnO叠层复合薄膜光催化活性提高的原因也进行了讨论。     

脉冲激光沉积法制备ZrW_2O_8薄膜(英文)

采用纯ZrW2O8陶瓷靶材,以脉冲激光沉积法在石英基片上沉积并退火处理后制备了ZrW2O8薄膜.利用X射线衍射仪、X射线光电子能谱 仪和扫描电子显微镜观察和确定r薄膜结构、化学组分和表面形貌,用划痕仪、表面粗糙轮廓仪测量了薄膜与基片之间的结合力和薄膜厚度.结果表明:脉冲激光沉积的薄膜为非晶态,膜层物质各元素之间的化学计量比与靶材成分一致;衬底未加热沉积的薄膜表而粗糙度较大,衬底温度为650℃ 时,薄膜表面平滑致密,粗糙度明显降低:非晶膜在1200℃密闭退火热处理3 min后淬火得到立方相ZrW2O8薄膜,退火后的薄膜品粒较大,同时 还出现一些沿晶界和晶内的裂纹缺陷.随着退火温度升高,薄膜与基片的结合力降低.     

溶胶-凝胶法制备BaPbO3导电陶瓷膜及其导电性能

以可溶性无机盐为原料,乙二胺四乙酸、柠檬酸和酒石酸为复合螯合剂,水为溶剂,采用溶胶-凝胶技术,在Al2O3衬底上制备了导电性能优良的钙钛矿结构BaPbO3(BPO)导电薄膜.利用X射线衍射和扫描电镜测试分析了热处理工艺对薄膜微结构的影响,用四探针法测定了薄膜方阻.结果表明:升高热处理温度和增加热处理次数的工艺会导致薄膜中Pb/Ba摩尔比降低和膜厚下降,从而使BPO薄膜方阻升高,薄膜导电性能下降.尤其是在膜层较薄的情况下,这种影响更加显著.采用在670℃保温10min的单次热处理方法,获得了方阻为4.65Ω/□的单一钙钛矿结构BPO相导电陶瓷薄膜.     

铅/钡摩尔比对铅酸钡陶瓷薄膜电阻率的影响

铅酸钡(BaPbO3)导电薄膜是目前最有潜力的锆钛酸铅(lead zirconate titanate,PZT)铁电器件底电极替代材料之一.用溶胶-凝胶法在氧化铝(Al2O3)基片上旋涂成型BaPbO3薄膜.由于氧化铅(PbO)的高温挥发性,因此有必要研究薄膜中的铅/钡摩尔比与薄膜电阻率之间的关系.实验比较了常规热处理(conventional thermal annealing,CTA)和快速热处理(rapid thermal annealing,RTA)方式,用X射线衍射和能量散射X射线能谱研究了热处理方式和热处理制度对薄膜方阻的影响,分别得到了CTA和RTA热处理条件下BaPbO3薄膜的最低方阻性能,与CTA热处理相比,RTA热处理技术需要更高的热处理温度,因此,CTA热处理技术更为适合BaPbO3薄膜的合成.     

添加少量F~-和P_2O_5对锆乳浊釉熔块中锆溶析行为的影响

本文应用热谱分析、X射线衍射、透射电镜和扫描电镜等研究了组成接近于一般硼锆釉熔块中添加少量F~-和P_2O_5对熔块熔制和热处理时锆溶析规律的影响.确定了它们在1290℃～1410℃范围内锆英石和ZrO_2溶解度和温度的关系以及750℃～1230℃温度范围内热处理的析晶程序、析出相组成、乳浊范围和锆英石、斜锆石析晶最大值温度.讨论了F~-和P_2O_5对锆英石析晶温度、晶粒形貌和大小以及釉烧时的粘度、流散性与乳浊效果的综合影响.     

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.