SiC_w一AlN复合材料工艺因素的研究

本文研究了工艺因素（烧结温度、添加剂组成和含量）对ＳｉＣ＿ｗ一ＡＩＮ复合材料的影响。结果表明：１８５０℃是较合适的复合材料烧结温度，复合材料力学性能与添加剂组成和含量有密切关系。Ｙ＿２Ｏ＿３与ＳｉＯ＿２在烧结中起的作用不同，Ｙ＿２Ｏ＿３与ＡＩＮ表面的Ａｌ＿２Ｏ＿３形成液相，是一种良好的烧结添加剂，而ＳｉＯ＿２由于与ＡＩＮ形成２７ＲＳｉａｌｏｎ多形体，反而阻碍材料致密化。在添加８ｗｔ％左右Ｙ＿２Ｏ＿３时。复合材料力学性能最佳，抗折强度σ５２０ＭＰａ，断裂韧性Ｋ＿（ｌｃ）＝４．９８ＭＰａ·ｍ￣（１／２）     

碳化硅陶瓷的热等静压烧结

系统地研究了不同添加剂（如Ａｌ２Ｏ３，ＡｌＮ和Ｂ４Ｃ等）在热等静压（ＨＩＰ）烧结条件下对ＳｉＣ陶瓷之致密机理，显微结构以及力学性能的影响，结果表明：在ＨＩＰ烧结过程中，Ａｌ２Ｏ３可以与ＳｉＣ颗粒表面的ＳｉＯ２生成低共熔的铝硅酸盐玻璃相，并有效地促进ＳｉＣ陶瓷的致密化，当添加３％（以质量计）Ａｌ２Ｏ３时，采用ＨＩＰ烧结工艺，在１８５０℃温度和２００ＭＰａ压力下降结１ｈ，就可获得相对密度和抗弯强度分别     

反应结合Al2O3—ZrO2—SiC复合陶瓷的制备工艺与性能

采用反应结合技术研究了Ａｌ２Ｏ３－ＺｒＯ２－ＳｉＣ复合陶瓷的制备工艺与材料性能，比较孙同的原料来源对致密化行为及材料性能的影响，含细Ａｌ２Ｏ３和粗ＳｉＣ的配方获得了最快的致密化速率及最高的烧结密度，该材料经１５５０℃烧结３０ｍｉｎ后再热等静压获得了近１００％的致密度和７６０ＭＰａ的弯曲强度。     

Y2O3—Al2O3—SiO2添加剂在低温烧结SiC中的作用

本文探讨了Ｙ２Ｏ３－Ａｌ２Ｏ３添加剂在低温无压烧结ＳｉＣ中的作用以及在Ｙ２Ｏ３－Ａｌ２Ｏ３添加剂中引入ＳｉＯ２的作用及机理,从而阐明了通过多项合理、有效复合添加降低ＳｉＣ烧结温度的可能性。     

无压烧结氮化硅陶瓷的研究

本文选用ＭｇＯ—Ａｌ２Ｏ３作为复合添加剂，采用无压烧结，设计Ｓｉ３Ｎ４一ＭｇＯ—Ａｌ２Ｏ３系烧结体、Ｓｉ３Ｎ４—ＳｉＣ—ＭｇＯ—Ａｌ２Ｏ３系烧结体，研究各种配方在不同成型压力不同烧结条件下烧结体的性能，测定室温抗折强度、体积密度、体积变化和气孔率。通过Ｘ射线衍射分析鉴定烧结体的物相结构，从而确定了最佳工艺范围。     

C－B_4C－SiC复合材料抗氧化性能的研究

对碳／陶瓷复合材料（Ｃ－Ｂ＿４Ｃ－ＳｉＣ）的抗氧化性能进行了研究，结果表明：Ｃ－Ｂ＿４Ｃ－ＳｉＣ复合材料抗氧化性能比碳素材料大大提高，而且烧结助剂对Ｃ－Ｂ＿４Ｃ－ＳｉＣ复合材料的抗氧化性能影响很大。在复合材料中分别加入了Ａｌ，Ａｌ＿２Ｏ＿３，Ｎｉ，Ｔｉ，ＴｉＣ，Ｓｉ等不同烧结助剂，发现添加Ｎｉ的材料抗氧化性能最佳，经１０００℃氧化１５ｈ后，氧化度小于０．５％；加入Ｔｉ，Ｓｉ和ＴｉＣ的次之，不加烧结助剂的又次之，加入Ａｌ和Ａｌ＿２Ｏ＿３的最差。     

SiC—Al2O3基复相陶瓷的N2—HIP研究

通过对热压ＳｉＣ－Ａｌ２Ｏ３复合材料进行了Ｎ２－ＨＩＰ后处理，制备得到Ｓｉ３Ｎ４－ＡｌＮ＝ＳｉＣ－Ａｌ２Ｏ３梯度材料，经Ｎ２－ＨＩＰ处理后，材料抗弯强度提高３５％－９５％，并得到经强度达１０３０ＭＰａ的ＳｉｅＮ４－ＡｌＮ／ＳｉＣｐ－ＳｉＣＷ－Ａｌ２Ｏ３复合材料。     

烧结温度对Al2O3＋WC陶瓷强韧性的影响

采用不同常压烧结（ＣＰ）温度制备了Ａｌ２Ｏ３＋ＷＣ复合陶瓷材料。利用扫描电镜（ＳＥＭ）、Ｘ－射线衍射,能谱分析（ＥＤＡＸ）等手段和三点弯曲,单边切口梁等力学方法研究了该材料的组织结构、力学性能及增韧机制。结果表明,１６００℃烧结Ａｌ２Ｏ３＋ＷＣ陶瓷各相结合致密、分布均匀且晶普微细,其断裂形式为沿晶断裂,室温断裂强度为５２０ＭＰａ;断裂韧性为６．２ＭＰａ·ｍ＾１／２,第二相ＷＣ弥散分布细化了基本晶粒     

Si3N4—MgAl2O4—Al2O3系材料无压烧结的研究

本文对Ｓｉ３Ｎ４－ＭｇＡｌ２Ｏ４－Ａｌ２Ｏ３系复合材料的无压烧结进行了研究，讨论了Ａｌ２Ｏ３含量对材料性能的影响及烧结工艺对材料性能和显微结构的相互关系。实验表明：两段法烧结可以得到性能良好的Ｓｉ３Ｎ４－ＭｇＡｌ２Ｏ４－Ａｌ２Ｏ３复合材料。     

硝酸盐烧结助剂对氮化硅陶瓷材料力学性能的影响

选用硝酸盐（Ａｌ（ＮＯ３）３·９Ｈ２Ｏ及Ｙ（ＮＯ３）３·６Ｈ２Ｏ）作为Ｓｉ３Ｎ４陶瓷烧结助剂替代传统的氧化物（Ａｌ２Ｏ３及Ｙ２Ｏ３）粉末助剂。利用硝酸盐易分解且易溶于酒精的特性,采用球磨混料、煅烧、再球磨工艺使烧结助剂在烧结体中弥散分布,从而使Ｓｉ３Ｎ４陶瓷更加致密,性能更加优越。通过对新旧两种工艺制作的Ｓｉ３Ｎ４瓷试样进行ＳＥＭ的图象观察分析及对硬度、抗弯、断裂韧性等力学性能的测试表明,本工艺在各方面都取得了良好的效果。     

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。