沉淀法制备α-Fe2O3纳米晶

研究了以FeCl3·6H2O和FeSO4·7H2O为源物质,用均相沉淀法和直接沉淀法制备α-Fe2O3纳米晶粉体,利用TEM、XRD、BET、H2-TPR手段对样品进行了表征.实验结果表明,均相沉淀法所制得α-Fe2O3粉体晶粒尺寸为20nm左右,比表面积大,反应性能好;直接沉淀法所制得粉体晶粒尺寸为80nm左右,比表面积小,反应性能相对差.     

反向化学沉淀法制备纳米ZrO_2超细粉体

以ZrOCl2.8H2O和NH3.H2O为原料,采用反向化学沉淀、有机物共沸蒸馏法制备超细ZrO2,用XRD、TEM、BET等技术研究粉体的组合结构、晶粒大小、比表面和孔径分布情况。结果表明,纳米ZrO2超细粉体由单斜和四方晶相组成,透射电镜分析提示产物粒径在10~20 nm;样品经400℃焙烧4 h后粉体的比表面积为115.64 m2/g,平均孔径为6.375 nm,总孔容为0.369 mL/g。该粉体具有高比表面性,可用于工业催化剂的载体。     

改进的沉淀包裹法制备ZrO2-Al2O3复合粉体

以工业Al2O3和ZrOCl2·8H2O为主要原料,采用改进的沉淀包裹法制备了n(3Y)ZrO2-Al2O3复合粉体,通过实验确定了主要工艺参数,所得粉体主晶相为t-ZrO2和α-Al2O3,分散性良好.     

醇水加热-水热法制备稳定Y-Ce-ZrO2纳米粉体

用醇水加热法制备前驱体,再由水热法制备摩尔分数为2 %Y2O3-5.5 %CeO2稳定的纳米四方相ZrO2.采用XRD,FTIR,TEM,SEAD分别对前驱体和纳米ZrO2粉体进行表征.研究了溶液的浓度、水浴时间、水热时间对ZrO2粉体晶型和形貌的影响.结果表明当溶液中ZrOCl2·8H2O的浓度为0.2 mol/L,醇水体积比例为5∶1,溶液加热至75 ℃,保温60 min;再经200 ℃水热处理6 h,制得的Y2O3-CeO2-ZrO2粉体的平均粒径为10 nm左右,粒度分布窄,分散性好.     

沉淀法制备Al2O3-ZrO2-Y2O3复合粉体的固相反应

采用化学沉淀法制备了不同配比的Al2O3-ZrO2-Y2O3复合粉体.通过X射线衍射研究了热处理过程中各物质之间的反应顺序及复合粉体的物相组成,结果表明升温过程中Y2O3优先与ZrO2反应生成固溶体,温度较高时,剩余Y2O3与Al2O3反应生成钇铝石榴石YAG;不同的制备工艺没有改变各物质之间的固相反应顺序,但影响了复合粉体中各物相的相对含量.     

直接沉淀法制备纳米ZnO粉体

以Zn（NO3）2·6H2O和ZnSO4·7H2O为锌源，以Na2CO3、（NH4）2CO3、NH3·H2O、NaOH作为沉淀剂，采用直接沉淀法制备了纳米氧化锌粉体。采用XRD和TEM测试手段对纳米氧化锌粉体进行了表征。结果表明：沉淀剂为Na2CO3时制备的纳米氧化锌粉体的晶体尺寸约为I5nm～40nm，浓度对纳米氧化锌粉体的粒径基本没有影响。在500℃煅烧2h后得到纳米氧化锌粉体具有六方纤锌矿结构。以（NH4）2CO3作沉淀剂，返滴定法制得的纳米氧化锌粉晶形完整、颗粒粒度分布较窄且粒径较小、分散性好。     

沉淀法制备纳米氧化铬粉体的研究

以Cr(NO_3)_3·9H_2O和NH3·H_2O为原料,采用直接沉淀法制备了纳米Cr_2O_3粉体。通过差热分析、X射线衍射、透射电镜、比表面积分析研究了粉体的制备过程和合成粉体的性能。所得纳米Cr_2O_3分散性良好,粒度分布均匀,平均粒径20~30nm,粒子形状为球形。     

纳米ZrO2(Al2O3)复合陶瓷的制备研究

以Al(NO3)3和ZrOCl2.8H2O为原料,采用化学共沉淀法合成了ZrO2/Al2O3复合粉体,并讨论了反应条件对样品的影响,通过DTA、XRD、分光光度计等手段对产品进行了表征,结果表明:采用合适的合成条件可以得到粒度分布均匀、粒径约30.1nm的ZrO2/Al2O3复合粉体。     

四方相氧化锆粉体制备工艺研究

以ZrOCl2·8H2O和Y2O3为主要原料,采用醇-水溶液加热结合共沉淀法制备出Y2O3稳定的纳米ZrO2复合粉体.利用X射线衍射(XRD)分析和扫描电子显微镜(SEM)研究了复合粉体的物相组成和晶粒大小.结果显示,当Y2O3含量为2mol%时,复合粉体由单斜相ZrO2和少量四方相ZrO2组成;当Y2O3含量为3mol%、4mol%时,粉体全部由四方相ZrO2,组成.750℃～900℃煅烧时,复合粉体的物相组成变化不大,但四方相ZrO2,的晶粒尺寸随煅烧温度升高而增大.     

沉淀法制备TiO2纳米粉体和微波干燥的研究

以TiCl4 和NH3· H2O为原料,采用沉淀法制备TiO2纳米粉体,利用XRD、TEM、DTA等分析测试手段对所得TiO2粉体的晶相组成、粒径分布等性质进行了研究,发现微波处理10min后,在700℃加热30min即可得到平均粒径小于35nm的TiO2 纳米粉体.     

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。