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以四氯化锆为锆源,乙醇为溶剂,采用溶剂热辅助熔盐法低温煅烧制备氧化锆纳米片。研究并讨论了熔盐种类和用量对氧化锆晶体生长和形貌的影响。结果表明:以NaCl和Na3PO4的混合物为熔盐,且m(前驱体):m(NaCl):m(Na3PO4)=10:10:1时,可以得到平均边长超过1.8μm,厚约70 nm,宽厚比大于10:1的单斜氧化锆纳米片。纳米片为单晶结构,无明显缺陷,主要暴露面为(001)晶面,其在熔盐中的形成符合自聚焦机理,包括溶解、扩散、吸附和生长过程,(001)面主导的氧化锆纳米片与表面能的理论计算结果吻合。 相似文献
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以钛酸四丁酯、氢氟酸、钼酸钠、硫代乙酰胺和硝酸银为原料,利用水热法和光沉积法成功在二硫化钼(MoS_2)/暴露(001)面TiO_2二维复合材料上沉积了银纳米粒子(Ag)。采用X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)、紫外可见吸收(UV-vis)对样品的相组成、表面形貌、表面元素组成和光响应范围进行表征测试,并在可见光下考察了复合材料降解亚甲基兰(MB)的光催化性能。结果表明粒径约为20~30 nm的Ag颗粒成功负载在MoS_2/暴露(001)面的TiO_2纳米片上(MT-001),Ag纳米粒子的等离子共振效应有效的改善了MT-001纳米片的光催化性能,改性后复合材料对MB的最佳降解率为89.72%,为同等条件下纯TiO_2纳米片的1.55倍。 相似文献
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采用Hummers法以石墨粉为原料制备氧化石墨烯(GO),采用球磨法制备不同尺寸的氧化石墨烯纳米片,分别使用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电镜(TEM)和马尔文激光粒度仪(Zetasizer Nano,Zs)进行结构表征.结果 表明,球磨法可制备不同粒径分布的氧化石墨烯纳米片;水泥基复合材料的SEM微观形貌以及力学性能测定结果显示当掺杂0.25%、球磨16 h制得的氧化石墨烯(80 ~ 184 nm),复合材料的抗折、抗压强度分别为12.1 MPa和73 MPa,相较于对照样品提高了47.56%和38.52%;小尺寸氧化石墨烯促进水泥内部形成规则有序的水化物,这些水化物在水泥内堆叠,形成相互交联的晶体网络,微观上改变复合材料内部结构,宏观上提高了其力学性能. 相似文献
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利用正交试验法探讨常压下制备纳米针状羟基磷灰石(HA)晶体。用FTIR、XRD及TEM分析了HA的结构和形貌。讨论了前驱体的浓度、反应搅拌速度、pH值(当pH≥10时)及分散剂N,N-二甲基甲酰胺(DMF)含量对羟基磷灰石晶体形貌及尺寸的影响。结果表明:在合成条件变化很宽的范围内,可以制得纯度高、分散性好的纳米级针状HA晶体。这种纳米针状HA晶体与自然骨中的HA晶体在组成、结构、结晶度和形貌方面有十分相似之处。另外,正交分析表明分散剂含量及前驱体的浓度对制备纳米级针状HA晶体的长度影响较为显著,而HA晶体的长径比受搅拌速度和pH值影响较大。 相似文献
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采用喷雾燃烧法制备SnO2纳米棒,对其形貌和结构进行了表征. 所制SnO2纳米棒长200~350 nm,直径30~50 nm,沿(001)方向生长. 考察了Fe掺杂量和Sn4+浓度对SnO2纳米棒形貌的影响,分析了其生长机理. 高温快速反应使Fe3+进入SnO2晶格,促使其沿(001)方向取向生长. 对乙醇等有机气体的气敏性能测试结果表明,棒状SnO2比颗粒状的具有更优的气敏性能,在100′10-6(j)乙醇浓度下,棒状SnO2的灵敏度为12,反应和恢复时间分别为9.5和6 s. 相似文献
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J. R. Aldrich S. P. Carroll W. R. Lusby M. J. Thompson J. P. Kochansky R. M. Waters 《Journal of chemical ecology》1990,16(1):199-210
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. 相似文献
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2008~2009年世界塑料工业进展 总被引:4,自引:1,他引:3
中蓝晨光化工研究院有限公司《塑料工业》编辑部 《塑料工业》2010,38(3)
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。 相似文献
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Cheng-Le Zhao Shane Porzio Alan Smith Haiyan Ge H. T. Davis L. E. Scriven 《Journal of Coatings Technology and Research》2006,3(2):109-115
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. 相似文献
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M. S. J. Simmonds W. M. Blaney F. Delle Monache M. Marquina Mac-Quhae G. B. Marini Bettolo 《Journal of chemical ecology》1985,11(12):1593-1599
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. 相似文献
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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. 相似文献
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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. 相似文献
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