氮化铝粉末的制备及扩大实验研究

主要进行了碳热还原法制备氮化铝粉末扩大实验研究。研究了不同的铝源、碳源、氮化温度、保温时间、添加剂对合成氮化铝粉末的影响,并采用XRD、SEM、化学物理分析等手段对中试实验制备的氮化铝粉末进行分析。研究结果表明,采用经砂磨处理的铝源B（α-Al₂O₃）和3^#碳源（乙炔黑）为原料,有助于碳热还原反应;采用添加剂C可以降低反应活化能,提高氮化率;造粒工艺有助于扩大实验的碳热还原反应。     

高氮压法制备氮化铝粉

对在加压氮气中金属铝粉的直接氮化和氧化铝粉的碳热还原氮化法制备氮化铝粉末进行了研究。研究结果表明：铝粉在高温高氮压下快速氮化，生成氮化铝，其临界温度为７００℃，氮气的临界压力为１ＭＰａ；在高氮压下，氧化铝可通过碳热还原氮化法生成氮化铝，其含氮量与保温温度，氮气压力和保温时间有关；在高氮压下，碳热还原氮化法制备氮化铝，可使用铝粉为晶种，能获得高质量的氮化铝（Ｎ〉３３％，Ｏ〈１％，按质量计）粉末。     

表面涂覆氮化铝粉末的抗水化性

研究了表面涂覆硬脂酸和吐温80对氮化铝粉末抗水化性能的影响。经过表面改性工艺处理的氮化铝粉末在20～60℃具有很好的化学稳定性,溶液pH值在9.88基本保持不变;改性处理的氮化铝粉末在水中长时间浸泡,X射线衍射分析表明其物相为AlN相。通过表面改性工艺在氮化铝粉末表面包裹一层有机化合物,能有效地抑制氮化铝与水的反应,阻碍水分子向氮化铝粉末表面侵蚀,提高氮化铝粉末在潮湿环境的抗水化能力。     

AlN陶瓷粉末的主要制备方法及展望

论述了国内外氮化铝陶瓷粉末的主要制备方法：铝粉直接氮化法、Al2O3碳热还原法、化学气相沉积法、溶胶-凝胶法、自蔓延高温合成法和等离子化学合成法，分析了这几种制备方法的特点和研究进展，为氮化铝粉末的制备指明了方向。     

等离子法制备氮化铝粉末原料的研究

以金属铝粉和氮气为原料通过直流电弧等离子法制备氮化铝粉末, 经羧酸与盐酸混酸在常温超声条件化学纯化后, X衍射分析表明制备出纯度高的氮化铝粉末;样品SEM照片显示处理后AlN粉末粒度为2～5 μm存有少量氮化铝晶须.     

纳米氮化铝的氨热合成及其光致发光

采用金属铝为前驱物,在450℃的氨热条件下,获得了高质量的氮化铝纳米粉体,测量了合成粉末的X射线衍射谱、光致发光谱和高分辨透射电子显微镜（HRTEM）,发现合成的粉末是平均粒度为32nm的纤锌矿结构的氮化铝,此AlN中存在蓝光发光带,另外,讨论了AlN在高压釜内的低温氨热合成机制。     

溶胶-凝胶法制备纳米氧化镁

以六水硝酸镁为前驱体,采用柠檬酸溶胶一凝胶法合成了不同粒径（10～100nm）和结晶度的纳米MgO粉末。研究了柠檬酸的作用机理、不同的工艺条件（水、无水乙醇、柠檬酸的加入量）对溶胶一凝胶稳定性的影响以及焙烧温度对粉末晶体粒径、结晶度的影响。结果表明：未引入柠檬酸时,凝胶的稳定性较差．氧化镁产物粒径较大且团聚较严重。引入柠檬酸后,并当水：六水硝酸镁：柠檬酸：乙醇=100：9：9：2．1（摩尔比）时可形成稳定的凝胶体系。焙烧温度对制得的MgO粉末的化学成分和晶体形貌基本无影响,但对粉末结晶度和粒径有显著的影响。500℃焙烧制得的纳米氧化镁粉末粒径为10nm左右,结晶度低,粒子间有一定的团聚;600℃的粉末粒径为30～60nm,结晶度有所提高,粒子的分散性较好;900℃的粉末粒径为50～100nm,结晶度更高,晶相更完整。     

磷酸二氢铝和磷酸球磨改性氮化铝粉末工艺研究

采用机械球磨法,以磷酸二氢铝和磷酸为改性剂,制备了抗水解氮化铝粉末,并研究了改性氮化铝粉末在水基球磨过程中的稳定性。通过X射线衍射(XRD)和氮含量测定对改性前后氮化铝粉末进行了表征,并讨论了磷酸二氢铝和磷酸的加入量、球磨时间和球料质量比对改性效果的影响。结果表明:在磷酸二氢铝和磷酸的添加质量分别为氮化铝质量的1%和2.5%、球磨时间为2 h、球料质量比为3∶1的条件下,氮化铝的改性效果最佳;改性氮化铝粉末在60℃水中浸泡24 h后,其氮质量分数为32.97%,且其X射线衍射谱图中未发现氢氧化铝相,说明其抗水解能力得到显著提高;改性氮化铝粉末在水中高速球磨16 h后,其氮质量分数约为32%,氮化铝悬浮液的pH约为6,说明其在水基球磨过程中具有较好的稳定性。     

氮化铝粉末的制备方法与机理

论述了氮化铝陶瓷粉末的各种制备方法,评述了各种方法的优缺点,总结了氮化铝形成的主要机理以及影响氮化铝粉末质量的因素.提供了一些有用的工艺参数和有关氮化铝粉末质量的数据.     

硼热还原法制备LaB_6粉末

研究了采用硼热还原法制备LaB6 粉末的反应合成工艺 .La2 O3-B系反应热力学分析表明 ,气体分压对LaB6 的形成有重要影响 ,减小气体分压可以明显降低LaB6 的合成温度 ;结合DTA测定结果 ,确定了制备LaB6 粉末的合成温度 .同时 ,对不同温度和保温时间条件下所生成的LaB6 粉末的相组成、颗粒尺寸与形貌以及纯度进行了测试分析 ,实验结果表明 ,La2 O3-B系制备LaB6 粉末的优化工艺是真空度133Pa ,192 3K保温 6h ,所合成的LaB6 粉末平均粒径为 6 μm ,纯度达 99.2 % ,颗粒形态比较规整 ,多数呈近似团块状 .     

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。