放电等离子（SPS）快速烧结TiB2陶瓷

利用放电等离子烧结技术制备纯TiB2陶瓷,烧结温度1600℃,压力30MPa,真空烧结,保温1—3分钟,即可获得相对密度达99％以上的致密烧结体。扫描电镜分析表明：烧结体晶粒细小,结构均匀;材料的晶粒随烧结温度的提高而长大;但烧结体的硬度分布不均匀。     

放电等离子(SPS)快速烧结TiB_2陶瓷

利用放电等高子烧结技术制备纯TiB2 陶瓷 ,烧结温度 160 0℃ ,压力 3 0MPa ,真空烧结 ,保温 1～ 3分钟 ,即可获得相对密度达 99%以上的致密烧结体。扫描电镜分析表明 :烧结体晶粒细小 ,结构均匀 ;材料的晶粒随烧结温度的提高而长大 ;但烧结体的硬度分布不均匀     

SPS工艺参数对Cu-Cr-Nb合金性能和组织的影响

利用放电等离子烧结(SPS)制备了Cu-8Cr-4Nb合金,研究了保温时间和升温速率对Cu-8Cr-4Nb致密度、电导率、力学性能和组织结构的影响。结果表明当:当烧结压力为30 MPa,烧结温度分别为800℃、900℃、950℃时,在保温时间为10 min、升温速率为100℃/min下,合金的相对致密度分别达到98.98%、99.09%、99.02%,接近理论致密度。合金电导率、硬度、抗拉强度也优于其他工艺参数。     

六方氮化硼陶瓷的烧结及其结构与性能EI北大核心CSCD

以亚微米级h-BN粉体为原料,在不添加任何烧结助剂的情况下,分别采用无压烧结、热压烧结和放电等离子烧结（SPS）制备h-BN陶瓷,采用X射线衍射和扫描电子显微镜对烧结后样品的物相组成和显微结构进行测试和观察,研究不同烧结方法对h-BN陶瓷的致密度、晶粒取向、显微形貌及力学性能的影响,对比分析了不同烧结方法下坯体初始致密度对h-BN陶瓷性能的影响。结果表明：无压烧结无法实现h-BN陶瓷烧结致密化,力学性能较差,而通过热压和放电等离子烧结的方法均能得到结构致密、力学性能较好的h-BN陶瓷。相比于传统的无压和热压烧结,放电等离子烧结方法制备的h-BN陶瓷具有更高的致密度和更好的力学性能,而且晶粒更均匀细小,烧结温度可降低200℃以上。此外,坯体初始致密度的提高能显著提高h-BN陶瓷的抗弯强度和断裂韧性,但对热压和放电等离子烧结制备的h-BN陶瓷致密化的影响较小。     

六方氮化硼陶瓷的烧结及其结构与性能

以亚微米级h-BN粉体为原料,在不添加任何烧结助剂的情况下,分别采用无压烧结、热压烧结和放电等离子烧结(SPS)制备h-BN陶瓷,采用X射线衍射和扫描电子显微镜对烧结后样品的物相组成和显微结构进行测试和观察,研究不同烧结方法对h-BN陶瓷的致密度、晶粒取向、显微形貌及力学性能的影响,对比分析了不同烧结方法下坯体初始致密度对h-BN陶瓷性能的影响。结果表明:无压烧结无法实现h-BN陶瓷烧结致密化,力学性能较差,而通过热压和放电等离子烧结的方法均能得到结构致密、力学性能较好的h-BN陶瓷。相比于传统的无压和热压烧结,放电等离子烧结方法制备的h-BN陶瓷具有更高的致密度和更好的力学性能,而且晶粒更均匀细小,烧结温度可降低200℃以上。此外,坯体初始致密度的提高能显著提高h-BN陶瓷的抗弯强度和断裂韧性,但对热压和放电等离子烧结制备的h-BN陶瓷致密化的影响较小。     

新型MAX相陶瓷Mo2Ga2C的放电等离子烧结

Mo2Ga2C是一种新型MAX相，该材料粉体已经可以被稳定的制备。但是Mo2Ga2C粉体不容易被烧结为致密的块体。本文采用放电等离子烧结技术(SPS)高温处理Mo2Ga2C粉体，通过对制备样品的物相组成和微观结构的表征，研究Mo2Ga2C的烧结性能。SPS烧结Mo2Ga2C 的最佳工艺参数为：烧结温度700℃，保温时间20min，轴向压力30MPa。在此条件下SPS烧结Mo2Ga2C样品相对密度达到71.81%。延长保温时间比升高烧结温度对Mo2Ga2C的致密化有更明显的助益；而增大轴向压力对样品的致密化产生负影响。相对于热压烧结，SPS可以在较低的温度快速制备Mo2Ga2C样品，但是制备的样品的致密度较低。     

放电等离子体烧结陶瓷材料微观组织演变模拟

研究Matlab仿真环境下加载Moore控件,构建放电等离子体烧结陶瓷刀具无边界四方二维仿真环境,对用于高精密切削的陶瓷刀具微观组织进行基于元胞自动机的仿真模拟。结果发现:增加烧结温度、保温时间,均有助于促进陶瓷微观晶粒生长,提升其致密度;但随着烧结温度、保温时间的增加,其致密度增幅持续下降收敛。说明在当前工艺条件下,选择1 700℃烧结环境和20 min保温时间,可以达到最佳工艺效果。     

合成和烧结工艺对PZT95/5陶瓷致密化影响的研究

以Pb3O4、ZrO2和TiO2为原料，Nb2O5为掺杂剂，利用固相法制备钙钛矿型PZT95／5陶瓷。采用正交实验优化合成和烧结工艺．综合分析了合成温度、合成时间、烧结温度、烧结保温时间、升温速率和烧结气氛对陶瓷体致密化影响的规律性变化。结果表明：其中合成温度和烧结温度是影响陶瓷致密化的重要因素。     

TiB2粒径对BN-TiB2复相陶瓷致密化和性能的影响

以平均粒径分别为8.1μm和12.2μm的两种TiB2粉末为原料,通过热压烧结方法制备BN–48%（质量分数）TiB2复相陶瓷,研究了TiB2粉末粒径对复相陶瓷致密化和性能的影响。结果表明：平均粒径小的TiB2粉末所制备的复相陶瓷致密化速率更快,致密度更高;在1 850℃烧结1.5 h后,表观相对密度为95.3%,体积...     

ZrB2-SiCpl复合陶瓷的SPS烧结行为及微观结构

利用放电等离子体烧结（spark plasma sintering,SPS）技术,在烧结温度、保温时间、压力和加热速率分别为1 600℃、5 min、30 MPa和100℃/min条件下制备硼化锆（ZrB2）–15%（体积分数）碳化硅晶片（SiCpl）复合陶瓷。研究ZrB2–SiCpl复合陶瓷的烧结致密化行为、微观结构...     

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。