用聚合物前驱体法低温合成铌酸锂纳米粉体

用聚合物前驱体法,以柠檬酸为配位剂．乙二醇为酯化剂．水为溶剂合成纳米铌酸锂（LiNbO3）粉体。研究发现：当柠檬酸和金属离子的摩尔比（下同）为3：1,柠檬酸和乙二醇的为1：2时,可形成稳定的Li-Nb前驱体溶液和凝胶。用差热-热重分析研究凝胶前驱体的热分解历程。用X射线衍射分析和红外光谱分析研究凝胶前驱体及其不同温度下煅烧所得粉体的相组成和结构。结果表明：Li-Nb凝胶前驱体在加热过程中分解形成LizCO3相．Li2CO3与Nb2O3发生固相反应生成LiNbO3。凝胶前驱体经800℃煅烧2h可以制备纯钙钛矿型的纳米LiNbO3粉体。     

聚合物前驱体法低温制备铌酸钾钠超细粉体

以柠檬酸为配位剂与金属离子配合,水作为溶剂,乙二醇为酯化剂,通过聚合物前驱体法制备(K0.5Na0.5)NbO3粉体.研究了柠檬酸(CA)和乙二醇(EG)的用量和pH值对溶胶性能的影响.采用XRD和TG-DSC研究了(K0.5Na0.5)NbO3晶相的形成过程,用SEM对所制得粉体的表面形貌进行了分析.结果表明:当前驱体溶胶的pH值为7.5,n(CA):n(metalion)=3:1,n(CA):n(EC)=1:2时,可以获得稳定性好的溶胶.凝胶前驱体在加热过程中先反应生成NaNbO3和K2Nb8O21,然后二者固相反应形成K0.5Na0.5NbO3.大部分晶粒呈方形的粒状,少数颗粒呈长柱状.讨论了晶粒形貌的形成原因.     

改进的溶胶-凝胶工艺制备ZrB_2纳米粉体

采用改进的溶胶-凝胶工艺,以ZrOCl2、H3BO3和蔗糖为原料,以柠檬酸（CA）为络合剂,聚乙二醇（PEG）为分散剂,制备出均匀稳定的Zr-B-C体系溶胶,再以氨水为调节剂,实现溶胶向凝胶转化。在1 500℃温度下经碳热还原反应制备出粒径尺寸约为40 nm,类球状ZrB2粉体。采用XRD、SEM等微观分析手段,对制备的纳米粉体进行了相组成与微观形貌分析。实验中研究了改进的溶胶-凝胶中柠檬酸络合-聚合技术对溶胶性能的影响。结果表明：当n（柠檬酸）∶n（Zr离子）为1∶3时,可获得稳定的Zr-B-C体系溶胶;增大n（B）/n（Zr）值,有利于得到纯度较高、且相组成可控的ZrB2纳米粉体;加入质量分数为1.0%的PEG时,粉体的团聚性能得到很大改善。     

溶胶-凝胶法制备LiNbO3薄膜的研究

对近年来有关溶液－凝胶法制备LiNbO3薄膜的研究进行了较详细的论述，分析讨论了在溶胶－凝胶法制备了LiNbO3薄膜过程中，各主要因素对LiNbO3薄膜制备的影响，简要地介绍了LiNbO3薄膜的一些性能。研究结果表明，目前可以用溶胶－凝胶法在蓝宝石及LiTaO3等基板（基板的晶格参数与LiNbO3的晶格参数失配较小）上制备出有光学应用的LiNbO3薄膜，制膜的热处理温度通常在500℃左右，讨论了溶胶－凝胶法制备LiNbO3薄膜过程中存在的主要问题、发展前景有今后的研究方向。     

铜铁双掺近化学计量比铌酸锂晶体生长及其光折变性能研究

采用优化工艺参数,在掺有6（mol）％K2O助溶剂熔体中,利用提拉法生长出系列铜、铁双掺近化学计量比LiNbO3晶体。通过二波耦合和透射光斑畸变法测试可知,在未掺和掺铁量不变情况下,随着掺铜量的增加,衍射效率逐渐增大且铜铁双掺铌酸锂晶体衍射效率要高于单掺铜铌酸锂晶体。而其写入时间和擦除时间逐渐减小;抗光损伤能力随着掺铜量的增加逐渐增强,且单掺铜铌酸锂晶体抗光损伤能力远远大于铜铁双掺铌酸锂晶体。     

Sol-gel法制备LiNbO_3粉末及其表征

以叔丁醇锂和乙醇铌为原料,用Sol-gel法制备的LiNbO3经烘干、热处理后得到LiNbO3粉末,通过对LiNbO3粉末进行IR和XRD表征,结果表明:当热处理温度达500℃时,LiNbO3结晶基本完全,热处理温度达700℃时,结晶完全。     

聚合物前驱体法制备铌酸钾钠纳米粉体

采用聚合物前驱体法,以柠檬酸(CA)为络合剂,乙二醇(EG)为酯化剂合成了纳米级(Na0.35K0.65)NbO3。研究了乙二醇用量对聚合物前驱体稳定性的影响,结果表明n(EG):n(CA)为2时能得到稳定凝胶,与乙二醇和柠檬酸聚酯化反应得到凝胶的理论配比一致。XRD分析表明聚合物前驱体在650℃煅烧2h可制得平均晶粒尺寸为24nm左右,纯单斜相结构的(Na0.35K0.65)NbO3纳米粉体,该合成温度比传统固相法降低了约300℃。     

PMN-PT弛豫铁电粉体和薄膜的无机盐-凝胶法制备

以无机盐为原材料、柠檬酸和EDTA为复合螯合剂, 乙二醇为溶剂, 合成稳定和均匀的Pb-Mg-Nb-Ti的复合有机盐前驱溶液;通过TGA, DTA和XRD等方法分析复合有机盐前驱物凝胶的热解过程和PMN-PT钙钛矿相形成的影响因素, 研究近全钙钛矿相铌镁酸铅-钛酸铅(PMN-PT)弛豫铁电粉体和薄膜的制备.     

溶胶-凝胶法制备Li-β-Al2O3纳米粉体

以硝酸锂、硝酸铝和碳酸氢铵为原料,采用溶胶-凝胶法制备了Li-β-Al2O3纳米粉体。研究了pH值、热处理温度和锂铝物质的量比[n（Li）/n（Al）]对制备Li-β-Al2O3纳米粉体的影响。用X射线衍射仪（XRD）、场发射扫描电镜（FE-SEM）和自动电位粒度仪对制备的粉体进行了表征。结果表明,当n（Li）/n（Al）=1∶5（为化学计量比时）,pH值在3.6左右时,可得到稳定透明的凝胶,经1000℃热处理后,产物为纯相的Li-β-Al2O3,FE-SEM结果表明粉体的粒度在100nm以内。     

碳包覆铁酸镍锂纳米晶体的制备

以金属离子的柠檬酸盐为前驱体，通过溶胶－凝胶和水热法相结合的方法，制备碳包覆的铁酸镍锂（ C－LiNi0．5 Fe2 O4）晶体。采用DSC－TG、 XRD、 SEM等技术对其结构进行研究。结构表明，样品粒径均匀，无团聚现象。     

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.