Si3N4超微粒的RF—CVD合成及其介电性质

利用自制的ＲＦ－ＣＶＤ装置合成了Ｓｉ３Ｎ４超微粒。着重考察了反应气混合方式对反应机理、化学含量、粒子形态及凝聚结构的影响。得到的Ｓｉ３Ｎ４粒子的典型尺寸为１０－５０ｎｍ，并且凝聚形成分形结构，其对应不同的反应温度合成的粒子的分形维数约为２．１５到１．７４之间。     

L—G法合成微细氮化硅粉和晶须

用Ｌ－Ｇ法合成微细氮化硅粉和晶须，在１０００－１３００℃热分解，并在Ｎ２气氛中保温８小时，产品均为无定形Ｓｉ３Ｎ４粉。当热处理温度提高到１４００－１４５０℃，保温１－２小时，得到α－Ｓｉ３Ｎ４粉末。当热处理温度在１５００℃，保温３小时，得到α－Ｓｉ３Ｎ４晶须。无定形粉的粒径为０．０７－０．３μｍ，颗粒呈不规则的空心球，蜂窝状。α－Ｓｉ２Ｎ４粉颗粒呈等轴形，粒径为０．１μｍ左右。α－Ｓｉ２Ｎ４晶须尺     

碳热还原法合成Si3N4的研究

研究了碳热还原法合成Ｓ３Ｎ４粉末中原料配比、Ｎ２流量，反应压力、反应莳晶种等因素对氮化的影响，获得了较佳的工艺参数，研制出氮含量大于３７％，平均粒径小于１．５μｍ的α－Ｓｉ３Ｎ４粉末。     

纳米SiC－Si_3N_4复合超细粉末的研制

用热化学气相反应法制备了纳米级Ｓｉｃ－Ｓｉ＿３Ｎ＿４复合超细粉末，讨论了工艺参数对复合超细粉末颗粒度、组成、结构等的影响，并制备出颗粒呈球形、颗粒尺寸均匀、分散性好、最小颗粒尺寸为８９Ａ的纳米级ＳｉＣ－Ｓｉ＿３Ｎ＿４复合超细粉末。     

TiN（Ni）对GPS Si3N4复合材料导电性能的影响

本文研究了ＴｉＮ（Ｎｉ）对ＧＰＳＳｉ３Ｎ４复合材料导电性能的影响，实验结果表明，添加ＴｉＮ粒子可显著降低Ｓｉ３Ｎ４复合材料的电阻率，Ｎｉ的加入对降低Ｓｉ３Ｎ４复合材料的电经有一定的作用，选择电阻率小于１Ω．ｃｍ的试样进行电火花加工，加工性能良好。     

Ni－W／F－Al_2O_3－SiO_2催化剂的表面吸附维

Ｎｉ－Ｗ／Ｆ－Ａｌ_２Ｏ_３－ＳｉＯ_２催化剂的表面吸附维朱建军，林西平（江苏石油化工学院，化工系，常州，２１３０１６）关键词表面吸附，分形维，Ｎｉ－Ｗ／Ｆ－Ａｌ_２Ｏ_３－ＳｉＯ_２催化剂１引言催化现象与多相催化剂的表面性质密切相关，催化剂表面形状是影响...     

Si_3N_4-Al_2O_3-ZrO_2系陶瓷表面氧化层组成的EPMA分析

利用ＥＰＭＡ和ＸＲＤ的分析方法，研究了Ｓｉ＿３Ｎ＿４－Ａｌ＿２Ｏ＿３－ＺｒＯ＿２系陶瓷材料表面氧化层组成。结果表明，Ｓｉ＿３Ｎ＿４－Ａｌ＿２Ｏ＿３－ＺｒＯ＿２系陶瓷材料表面氧化层是由方石英相、ＺｒＳｉＯ＿４相和含有Ａｌ＿２Ｏ＿３、ＣａＯ等的ＳｉＯ＿２玻璃相所组成，其中ＳｉＯ＿２玻璃相中Ａｌ＿２Ｏ＿３、ＣａＯ等的含量，随着氧化时间的增加而逐渐增加。     

Sialon陶瓷的合成和应用

Ｓｉａｌｏｎ陶瓷的合成和应用都兴红张广荣隋智通（东北大学材料与冶金学院·沈阳·１１０００６）１Ｓｉａｌｏｎ陶瓷的合成Ｓｉａｌｏｎ陶瓷与Ｓｉ３Ｎ４陶瓷相比不仅结构，性能不同，更突出的优点是它的烧结性能远高于Ｓｉ３Ｎ４陶瓷，这主要是由于Ｓｉ３Ｎ４是...     

低氮气压下燃烧合成氮化硅粉

对硅粉在低压氮气中的高温自蔓延合成（ＳＨＳ）Ｓｉ３Ｎ４粉末过程进行了探讨,实验证明了０．６ＭＰａ－０．７ＭＰａ的低氮气压下燃烧合成Ｓｉ３Ｎ４的可行性,超始原料中加人适量的Ｓｉ３Ｎ４粉作稀释剂,可促进Ｓｉ粉向Ｓｉ３Ｎ４的氨化转变。产物为１μｍ～２μｍ纯度较高的Ｓｉ３Ｎ４粉,燃烧温度随氮气压力与孔隙率而变化,而随配料组成的变化不明显。     

低氮气压下燃烧合成氮化硅粉

对硅粉在低压氮气中的高温自蔓延合成（ＳＨＳ）Ｓｉ２Ｎ４粉末过程进行了探讨,实验证明了０．６ＭＰａ－０．７ＭＰａ的低氮气压下燃烧合成Ｓｉ３Ｎ４的可行性,超始原料中加入适量的Ｓｉ３Ｎ４粉作稀释剂,可促进Ｓｉ粉向Ｓｉ３Ｎ４的氮化墨迹。产物为１μｍ－２μｍ纯度较高的Ｓｉ３Ｎ４粉,燃烧温度随氮气压力与孔率而变化,而随配料组成的变化不明显。     

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。