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1.
本文高镍前驱体采用控制结晶法制备,研究了控制结晶法与高镍前驱体的物理性能及微观结构之间的关系,分析了各个主要因素对高镍前驱体制备的影响。找到影响高镍前驱体制备的因素依次是氨水浓度、p H值、反应温度、固含量、反应时间、成分含量、杂质、反应气氛。通过分析讨论找到了最佳工艺条件,并成功制备样品,研究了高镍前驱体在最佳工艺条件制备得到高镍正极材料,通过XRD物相分析单一物相,层状结构完整,微晶结构均匀而清晰。  相似文献   

2.
采用不同前驱体,硝酸镍、醋酸镍、氯化镍和草酸镍,十二烷基磺酸钠作为有机改性剂,浸渍法制备一系列纳米镍催化剂,并用XRD和TEM等技术对四组催化剂的物相、比表面积进行了表征。以葡萄糖加氢制山梨醇反应考察催化剂的活性,结果表明,纳米镍催化剂的活性与镍前驱体的性质,以及纳米镍的尺寸有着紧密关系。其中以氯化镍为前驱体制备的催化剂颗粒尺寸小且散度更高,在温度120℃,压力3.5 MPa下葡萄糖转化率可达93.9%,山梨醇的选择性可达90.1%,同时可循环使用3~4次。  相似文献   

3.
以氧化钇、浓硝酸为原料,草酸铵为沉淀剂,十六烷基三甲基溴化铵为分散剂,采用草酸铵沉淀法制备纳米氧化钇前驱体,将前驱体在空气中焙烧制备纳米氧化钇粉体。用差热-热重分析确定了前驱体分解温度,用 X射线衍射和扫描电镜对样品进行表征,用激光粒度仪测量不同反应物物质的量比所得产品的粒度分布,得到制备纳米氧化钇最佳条件。实验表明,在最佳条件下可以制得平均粒径为40 nm的氧化钇粉体,其形貌为椭球形。  相似文献   

4.
白璐  项顼  李峰 《工业催化》2008,16(10):66
以层状双金属氢氧化物/碳复合物为前驱体通过原位还原法进行了高分散纳米镍粒子的制备。通过X射线衍射(XRD)、透射电镜(TEM)、比表面积(BET)和热分析(TG-DSC)对产物结构与形貌以及催化性能进行了研究。结果表明,在惰性气氛下前驱体经还原得到高分散的纳米镍粒子,粒径约10 nm。复合前驱体中的碳作为还原剂,将层状前驱体衍生的金属氧化物原位还原为金属镍纳米粒子,还原反应进行彻底;反应温度对还原产物的相组成有重要影响。另外,纳米镍对高氯酸铵热分解显示了较好的催化作用。  相似文献   

5.
高活性镍基加氢催化剂是以硅藻土为载体、镍为活性组分采用共沉淀法制备的催化剂。考察了硅藻土比表面积、镍与硅藻土质量比、催化剂前驱体煅烧温度、催化剂前驱体还原温度等条件对催化剂活性的影响。通过实验数据分析,最终确定了高活性镍基加氢催化剂的最佳制备条件:硅藻土比表面积为284.2 m2/g,镍与硅藻土质量比为0.8,催化剂前驱体煅烧温度为500℃,催化剂前驱体还原温度为600℃。在此条件下制备的镍基加氢催化剂最优,经过棕榈油加氢评价后碘值最小,说明催化剂活性最高。  相似文献   

6.
以硝酸钕、草酸铵为原料,六偏磷酸钠为分散剂,采用沉淀法制备纳米氧化钕前驱体,将前驱体在空气中焙烧制备纳米氧化钕粉体。研究了反应温度、物料浓度等因素对粉体的影响,用激光粒度仪测得样品的粒度分布,用X射线衍射和扫描电镜对样品进行表征。实验表明,在最佳条件下可以制得平均粒径为100 nm的片状氧化钕粉体。  相似文献   

7.
采用阳离子交换树脂作为炭载体的前驱体,经过镍离子交换,再经热解后制备了一种纳米镍/炭(n—Ni/C)复合材料。以XRD、SEM、TEM、EDS为主要分析手段研究了热解条件对纳米镍在n—Ni/C复合材料中的形貌、大小和分布情况的影响。结果表明:通过热解条件可以控制n—Ni/C复合材料中纳米镍的粒径;TEM和SEM—EDS观察表明热解所得n—Ni/C复合材料中的纳米镍颗粒大小均匀、分散性好。差热分析(DTA)研究结果表明加入n-Ni/C可增加高氯酸铵(AP)的表观放热量,降低AP的高温分解峰,最大可达95℃。  相似文献   

8.
我们发明了一种新型的纳米晶材料合成方法。以硝酸锂、硝酸镍、硝酸铁和草酸为原料,采用溶胶-凝胶法制备出了铁酸盐前驱体,通过高温煅烧得到了纳米晶铁氧体-铁酸镍锂,其颗料尺寸为纳米级(100 nm)。我们所合成的铁酸镍锂对RDX和AP的分解均有推进作用,降低了RDX和AP的热分解温度。  相似文献   

9.
本发明涉及Ni—Zn铁氧体与SiO2的复合纳米纤维及其制备方法,属于无机非金属复合功能材料及其制备领域。本发明以聚乙烯吡咯烷酮(PVP)为络合剂与乙酸镍、乙酸锌、硝酸铁和正硅酸乙酯反应制得前驱体溶液。  相似文献   

10.
杨少锋  晏彬彬  吴阳  李凯  陈维平 《硅酸盐学报》2012,40(11):1647-1651
采用Ni(NO3)2·6H2O前驱体液相包覆技术对纳米Al2O3颗粒进行金属化处理,经过干燥、加热分解和高温氢气还原处理后,前驱体完全转化为金属Ni晶体,从而获得镍涂覆的Al2O3颗粒。X射线衍射、透射电子显微镜和能谱分析结果表明:金属镍包覆在纳米Al2O3颗粒表面。包覆的纳米Al2O3颗粒经过热压烧结制备的陶瓷体与金属铝之间的润湿角为72.5°,明显改善了陶瓷与金属之间的润湿性。  相似文献   

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12.
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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14.
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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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   

18.
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   

19.
收集了2007年7月~2008年6月世界塑料工业的相关资料,介绍了2007~2008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、不饱和聚酯树脂、环氧树脂)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   

20.
收集了2005年7月~2006年6月国外塑料工业的相关资料,介绍了2005—2006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生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。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(聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、通用热固性树脂(酚醛、聚氨酯、不饱和树脂、环氧树脂)、特种工程塑料(聚苯硫醚、液晶聚合物、聚醚醚酮)的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。  相似文献   

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