四氧化三钴催化燃烧形貌效应研究

通过水热法和微乳辅助水热法,合成了海胆状、片状以及球形3种不同形貌的四氧化三钴,并对其甲烷以及一氧化碳催化燃烧性能进行了测试,结合BET、SEM、XRD等微观结构表征,分析了催化性能和微观结构的构效关系。结果表明,四氧化三钴对甲烷和一氧化碳催化燃烧反应均具有明显的形貌效应,但四氧化三钴形貌对两种反应的影响表现出不同的规律。对于一氧化碳催化燃烧反应,海胆状四氧化三钴催化性能最佳,球形四氧化三钴优于片状四氧化三钴;对甲烷催化燃烧反应,海胆状四氧化三钴>片状四氧化三钴>球形四氧化三钴。     

四氧化三钴催化燃烧形貌效应研究

通过水热法和微乳辅助水热法,合成了海胆状、片状以及球形3种不同形貌的四氧化三钴,并对其甲烷以及一氧化碳催化燃烧性能进行了测试,结合BET、SEM、XRD等微观结构表征,分析了催化性能和微观结构的构效关系。结果表明,四氧化三钴对甲烷和一氧化碳催化燃烧反应均具有明显的形貌效应,但四氧化三钴形貌对两种反应的影响表现出不同的规律。对于一氧化碳催化燃烧反应,海胆状四氧化三钴催化性能最佳,球形四氧化三钴优于片状四氧化三钴;对甲烷催化燃烧反应,海胆状四氧化三钴片状四氧化三钴球形四氧化三钴。     

六水合氯化钴脱水过程分析

六水合氯化钴是制备钴酸锂电池用四氧化三钴粉末的主要原料,不同结晶水含量的氯化钴制得的四氧化三钴其粒度及分散性存在差异,以二水合氯化钴为原料,通过高温水解反应可以得到粒度细小、分布均匀的四氧化三钴粉末。通过热重差热分析(TG-DTA)测定了六水合氯化钴的脱水过程,研究并分析了脱水过程中干燥温度以及料层厚度对脱水的影响,为研究以六水合氯化钴为原料通过高温水解反应制备四氧化三钴提供理论依据。结果表明:温度高、料层薄均可提高六水合氯化钴的脱水速率;在120℃下干燥230 min可以脱除4个结晶水,变成二水合氯化钴,干燥360 min可脱除5个结晶水,变成一水合氯化钴;当温度升高到220℃并且累积干燥时间达到21 h时,六水合氯化钴可脱除全部结晶水。     

均匀沉淀法合成纳米四氧化三钴工艺优化

在均匀沉淀法合成纳米四氧化三钴的过程中，采用了均匀设计方法对合成工艺过程进行优化设计。依据纳米四氧化三钴粒径试验结果，经过回归分析，建立了产物粒径与相关工艺条件的回归方程，由回归系数确定各因素的影响，进而筛选出合成纳米四氧化三钴的最优条件。在优化的条件下得到的纳米四氧化三钴粒径为22nm。     

络合剂对四氧化三钴合成的影响研究

摘要：本文以6种不同的络合剂对四氧化三钴生产的为研究对象。用尿素做络合剂生产出来的四氧化三钴颗粒松散用DTPA做络合剂生产出来的四氧化三钴颗粒松散,松装密度较小,也不适宜用于工业生产。L-组氧酸,柠檬酸,酒石酸钠和EDTA-2Na作为络合剂生产出来的四氧化三钴颗粒较为紧密,松装密度较大;L-组氨酸做为络合剂得到的四氧化三钴粒度较大,适宜生产大粒度的产品,而用柠檬酸,酒石酸钠和EDTA-2Na得到的四氧化三钴分别在3．0μm、4．0μm、5．0μm左右,可以为生产同-梯队不同型号的产品使用。     

碱式碳酸钴在微波场中的吸波特性及升温行为研究

利用微波谐振腔,分析物料放入前后波谱图的衰减值和相对频移,研究碱式碳酸钴、四氧化三钴及二者混合物的微波吸波特性;并通过微波加热物料,探讨物料在微波场中的升温行为。研究结果表明:碱式碳酸钴吸波性能较弱,而四氧化三钴具有很强的吸波性能,二者混合物的吸波性能随着四氧化三钴配比的增加而增强;在微波功率为820 W条件下,配加四氧化三钴质量分数为20%的碱式碳酸钴在微波场中加热110 s后,温度即可达到375 K;物料在微波场中的升温快慢与微波功率成正比;升温行为的研究结果与吸波特性的测定结果相吻合。微波煅烧碱式碳酸钴制备四氧化三钴是可行的。     

纳米四氧化三钴的合成表征及各自在电化学性能的研究

以六水合硝酸钴(Ⅱ)、六水合氯化钴(Ⅱ)为原料制备纳米级别的棒状四氧化三钴、管状四氧化三钴及片状四氧化三钴。利用XRD对制备的产物与原料、中间体进行对比研究,利用SEM观察产物形貌,并利用电化学工作站对不同产物的电化学性能进行研究。经研究发现,在以2 mol/L KOH溶液为电解液的条件下,四氧化三钴纳米棒的电化学性能最为优异。     

四氧化三钴负极材料合成方法研究进展

四氧化三钴作为锂离子电池负极材料已被广泛研究。近年来对四氧化三钴电极材料性能的改进一直是锂离子电池研究领域的热点和前沿之一。综述了四氧化三钴作为锂离子电池负极材料的最新研究进展,从结构和充放电机理、合成方法及复合改性等方面进行了讨论,指出了其作为锂离子电池负极材料的发展趋势。     

纳米四氧化三钴的合成表征及各自在电化学性能的研究

以六水合硝酸钴(Ⅱ)、六水合氯化钴(Ⅱ)为原料制备纳米级别的棒状四氧化三钴、管状四氧化三钴及片状四氧化三钴。利用XRD对制备的产物与原料、中间体进行对比研究,利用SEM观察产物形貌,并利用电化学工作站对不同产物的电化学性能进行研究。经研究发现,在以2 mol/L KOH溶液为电解液的条件下,四氧化三钴纳米棒的电化学性能最为优异。     

湿法制备电池级四氧化三钴的研究

以氯化钴和碳酸钠为原料,采用湿法通过控制反应物的摩尔比、pH值、反应温度得到碳酸钴前驱体,前驱体经过二段烧结得到纯相的四氧化三钴微粉。用XRD、SEM等分析测试技术对氧化钴微粉进行表征。结果表明,四氧化三钴的粒径在2~11μm,平均粒径为8μm,粒径分布均匀,呈类球形颗粒,杂质元素含量低,满足了电池级四氧化三钴的要求。     

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.     

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.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

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.     

2007～2008年世界塑料工业进展

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.     

2005～2006年国外塑料工业进展

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。