大颗粒氧化铈粉体的合成及粒度控制

采用正交试验法,研究了用草酸溶液作沉淀剂,直接沉淀合成大颗粒二氧化铈粉末,并对影响氧化铈粉末粒度的各种因素进行了详细研究。结果表明,适当降低硝酸铈质量浓度可以有效控制氧化铈粉末的粒度;同时沉淀剂浓度、料液酸度、煅烧温度均对氧化铈粉末的粒度有较大影响,得出了制备粒度为30-40μm的大颗粒氧化铈粉体的最佳工艺条件为：硝酸铈质量浓度70 g/L,料液酸度0.5 mol/L,草酸沉淀剂的质量浓度100 g/L,煅烧温度900-950℃。按此工艺参数可以直接合成粒度为38.521μm的氧化铈粉末。     

爆轰法制备纳米氧化铈的提纯工艺参数研究

通过正交试验研究爆轰法制备氧化铈粉末的提纯工艺,并对影响氧化铈纯度的各种因素进行详细的研究。研究表明,适当的降低氧化铈的质量浓度可以有效的提升氧化铈粉体的纯度;同时酸洗的时间、酸洗的反应温度、硝酸浓度均对氧化铈粉末的纯度有较大影响,得出了氧化铈粉体提纯的最佳工艺条件为:酸洗时间12 h,氧化铈质量浓度66.7 g/L,硝酸浓度0.6 mol/L,酸洗反应温度90℃。按此提纯工艺可以得到纯度为99.95%的氧化铈粉末。     

固相反应法制备超细氧化铈的球磨工艺优化研究

以铈盐与草酸为原料,室温下通过机械球磨固相反应法合成前驱体草酸铈,经热分解得到超细氧化铈粉末。利用TG-DSC表征了前驱体粉末在热分解过程中的变化情况,利用X射线衍射(XRD)、扫描电镜(SEM)表征了产物的组成、大小和形貌。实验对比研究得出的较佳工艺为:机械球磨,填充率为40%,球料质量比为15∶1,球磨时间为2.5 h,400℃下煅烧2 h。在此条件下制备的氧化铈颗粒粒径约为300 nm,大小均匀,颗粒分散性较好。     

一种用初级氧化锌粉制备活性氧化锌工艺

研究了硫酸浸出初级氧化锌粉末制备活性氧化锌的工艺，讨论了浸出过程中液固质量比、硫酸质量分数对浸出率的影响。在硫酸锌溶液净化中，选择过硫酸铵除铁的方法。确定了活性氧化锌制备工艺参数，采用廉价的碳酸氢铵作为锌的沉淀剂制备前驱体，选择600℃煅烧前驱体4h。采用透射电镜和X衍射对产物活性氧化锌进行了表征。结果表明：活性氧化锌的粒度分布均匀，形貌为近似球形，其平均粒径为80nm，产品纯度高。采用化学法分析产物，其氧化锌质量分数为99．18％。     

醇水共沉淀法制备氧化锆超细粉末及团聚控制

以氯氧化锆和氨水为原料，在醇水溶液中制得氧化锆前驱体，经过陈化和低温处理后干燥，前驱体在600℃下煅烧后球磨得到氧化锆超细粉末。采用TG—DSC，XRD，TEM分别对制备的粉末进行了分析。研究表明在共沉淀过程中引入无水乙醇，采用低温处理工艺，能减少粉末的团聚，避免硬团聚的形成。运用该方法可以制备出粒度为20～30nm、少团聚的超细氧化锆粉末。     

不同煅烧制度下制备超细碳酸钙的研究

以石灰石为前驱物，利用化学法合成超细碳酸钙粉末，探讨了煅烧制度因素对碳酸钙的形成及颗粒粒径的影响，对合成的样品进行SEM分析。实验结果表明：通过控制煅烧条件，可以制得平均粒径在100纳米左右的碳酸钙粉末。     

碱式碳酸锌前驱体合成纳米氧化锌及数据挖掘

以硫酸锌粉末与加有聚乙二醇-400为表面活性剂的碳酸钠粉末为原料，先经室温固相反应得到前驱体混合物，然后用水洗去混合物中的可溶性无机盐后将其烘干得到前驱体碱式碳酸锌，前驱体经350℃煅烧得到纳米氧化锌。基于均匀设计得到的数学模型，对试验的规律进行了数据挖掘的动态分析，明确获悉前驱体的煅烧温度还可以降低一些。     

球形氧化锆的湿法制备过程研究

以氯氧化锆和碳酸氢铵为原料，采用连续反应沉淀法制备了微米级球形氧化锆前驱体，此前驱体在500℃下于空气气氛中煅烧2h得到球形氧化锆粉体。探讨了锆盐溶液浓度、加料速度、pH、反应时间对粉体颗粒粒径大小及其分布的影响。经SEN，XRD，TG—DSC和激光粒度测试仪分析，结果表明在最佳工艺条件下制备的氧化锆前驱体颗粒呈球形，分散性好，粒径分布在8—18μm。     

不同煅烧制度下制备超细碳酸钙的研究

以石灰石为前驱物 ,利用化学法合成超细碳酸钙粉末 ,探讨了煅烧制度因素对碳酸钙的形成及颗粒粒径的影响 ,对合成的样品进行SEM分析。实验结果表明 :通过控制煅烧条件 ,可以制得平均粒径在 10 0纳米左右的碳酸钙粉末     

金刚石工具用Ni-Co合金粉末的制备及表征

在金刚石工具领域,纯钴基以及钴基金刚石工具具有优良的使用性能,但钴价格很高,使纯钴基以及钴基金刚石工具的使用受到了限制,所以代钴研究具有重大的实际意义.镍和钴同属于过渡族元素,两者物理和化学性质非常接近,故镍代钴有一定的可行性.采用草酸盐共沉淀法得到前驱体,然后将前驱体煅烧还原的工艺制得Ni-Co预合金粉末;对前驱体进行了X射线、热(差热和热重)分析,结果表明,通过共沉淀法得到的前驱体是固溶体;对预合金粉末进行了性能表征,所制得的Ni-Co预合金粉末氧含量低,形貌近似球形,粒度均匀;通过共沉淀反应前的成分设计,可制备出成分含量连续变化的预合金粉末;通过改变制备工艺参数,可制取不同粒径的粉末.本实验的粉末成分设计是70Ni-30Co(wt%).     

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.     

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。     

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.