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过渡金属氮化物催化性能研究进展 总被引:1,自引:0,他引:1
过渡金属氮化物具有类似于Pt族贵金属的催化性能得到了广泛的研究.综述了过渡金属氮化钼及助剂促进的氮化钼在加氢脱硫与脱氮、氨合成与分解、芳烃加氢和其他涉氢反应(如炔烃、烯烃加氢、丙酮缩合、肼的分解)中的应用,并介绍了其他金属氮化物(如氮化钒、氮化钴)在催化反应中的应用. 相似文献
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过渡金属碳化物由母体金属化合物经渗碳反应而形成,具有多变的结构组成和类贵金属的电子性质,是一类具有广泛应用前景的廉价催化材料,在催化加氢、加氢脱氧(hydrodeoxygenation,简写为HDO)和氢解等诸多重要催化反应中表现出优异的性能。近年来,对过渡金属碳化物的研究及其催化应用取得显著进展,但由于其固有的复杂性如相组成、表面缺陷与物种等导致构效关联等科学问题尚不清晰,仍有待进一步研究。本文综述了近年来过渡金属碳化物在生物质热解油中代表性含氧化合物HDO制备燃料和高附加值化学品中的研究进展,在分析了代表性含氧化合物反应路径的基础上,重点介绍了过渡金属碳化物的设计与合成策略及其结构与HDO催化性能关联,并展望了过渡金属碳化物作为生物质基含氧化合物HDO催化材料的研发方向与发展前景。 相似文献
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金属氮化物/碳化物加氢催化剂研究进展 总被引:1,自引:0,他引:1
过渡金属氮化物与碳化物是一类间充性化合物,其结构特点决定其在催化反应上具有独特的催化效果。本文介绍了过渡金属氮化物与碳化物基本性质与作为加氢催化剂的制备进展,综述了其在催化加氢,脱氢,脱硫等方面的研究进展,并展示了重要的理论研究意义和潜在的应用前景。 相似文献
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以溶胶-凝胶法所制备的复合氧化物La2Ti2O7粉体为前驱体,氨气为氮化剂,制备了LaTiO2N氧氮化物粉体.采用热重-差热分析(TG-DTA),X射线(XRD)、紫外-可见吸收光谱(UV-vis)、氮吸附比表面仪(BET)、透射电镜(TEM)对前驱体氧化物和合成的氧氮化物进行了表征.结果表明:合成的氧化物La2Ti2O7粉体活性高,在900℃氮化12 h可制备出比表面积为13.51 m2/g的LaTiO2N氧氮化物粉体.随着氮化温度的升高,氧氮化物的紫外-可见吸收边界有明显的红移,纯相LaTiO2N的吸收边界为580 nm. 相似文献
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以共沉淀法制备的钛和铬的摩尔比为4:6的TiO2/Cr2O3纳米复合粉体为前驱体,氨气为氮化剂,制备了钛铬双金属氧氮化物纳米粉体。采用Auger电子能谱、X射线衍射、透射电子显微镜、BET比表面积、电子探针等技术对氧化物复合粉体和合成氧氮化物粉体进行了表征。结果表明:前驱体组成均匀、比表面积大、反应活性高,800℃氮化8h可以合成X射线衍射纯立方相钛铬双金属氧氮化物纳米粉体e粉体呈球形,晶粒尺寸在20~35nm,比表面积达35.62m^2/g,基本无团聚。氮化前后粉体的氧含量和氮含量发生了明显变化,粉体的组成可以用Ti0.4Cr0.6OxNy表示。 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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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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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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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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Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed. 相似文献