冷等静压成型压制工艺对坯体性能的影响

将Si粉(粒度≤0.044mm)和聚乙烯醇水溶液(PVA,其中聚乙烯醇质量份数为5%)按85:15的质量比混匀,过筛造粒,振动装料后进行冷等静压成型,研究了成型压力、升压速度和保压时间对硅粉坯体强度和密度的影响。研究表明:对于硅粉来说,随成型压力的增加,坯体的密度和强度随着增大,但压力增大到275MPa后,坯体密度和强度趋于恒定,密度约为1.61g/cm~3,强度约为2.0MPa。保压时间对截面尺寸小的坯体的密度和强度影响不大,密度最大值与最小值相差约0.03g/cm~3,变化率仅为1.96%;强度最大值与最小值相差约0.1MPa,变化率约为6.71%。升压速度对截面尺寸小的坯体的密度和强度影响不大。     

封接玻璃密度与粘结剂含量对造粒粉性能的影响

选用不同种类玻璃粉末进行喷雾造粒实验,研究了密度与粘结剂含量对玻璃造粒性能与烧结性能的影响。结果表明,相同工艺条件下,玻璃粉密度增大,所得造粒粉平均粒径增加、球形度降低,保持相同流动性需要更高的粘结剂含量;造粒粉中的粘结剂含量影响封接玻璃的排胶温度与保温时间,对封接性能无明显影响。     

等静压成形工艺的优化研究

本文研究了等静压成形工艺过程中氧化铝造粒粉料成形后的坯体相对密度和强度随着各成形参数的变化而变化的规律,并进一步研究了其对烧结收缩的影响。实验表明:随着压力的增大,坯体密度逐渐提高,强度也相应增大;保压时间对坯体的相对密度影响不明显;在成形压力范围内,坯体相对密度对烧结之后的试样致密度影响不大。     

喷雾造粒ZrO2粉料坯体性能的研究

以喷雾造粒ＺｒＯ２粉料为研究对象,通过对粉料的压力－密度曲线及坯体的ＳＥＭ显微结构分析,发现喷雾造粒粉料的粒度分布对坯体密度的影响较小;颗粒强度的大小是获得均匀的坯体结构的关键,颗粒的强度与其大小及环境湿度有关,因此颗粒适当的增塑及去除大颗粒均有利于坯体显微结构的改善。     

粘结剂对喷雾造粒ZrO2(Y2O3)粉末特性的影响

采用喷雾造粒工艺对及ZrO2(Y2O3)粉体进行造粒，研究喷雾造粒过程中粘结剂含量对粉料流动性、填充性、造粒团聚体强度的影响，并对坯体成形过程中团聚体的破碎行为进行了分析。结果表明：喷雾造粒过程中粘结剂含量较高时，造粒团聚体粒子具有良好的填充性，但粒子强度高，在成形过程中不易破碎，将阻碍致密化烧结。     

精确控制堇青石玻璃陶瓷的烧成收缩率

液相烧结体系的产品烧成收缩率很难得到精确控制,用粉煤灰作原料烧结堇青石玻璃陶瓷,确定了产品的烧成收缩率与坯体的体积密度有对应的负相关的曲线关系。可以通过这种曲线关系用坯体的体积密度来预测产品的烧成收缩率和产品在不同方向上的收缩率,并且通过控制坯体的体积密度来精确控制产品的尺寸。还从产品制备工艺上确定了粉料加水量,练泥造粒过程,坯体成型压力对坯体的体积密度的影响关系。     

花岗岩锯泥烧结建筑陶瓷工艺研究

为推动大宗固废的综合利用，减轻花岗岩锯泥对环境的污染，本文探索了一种使用花岗岩锯泥、高铝黏土及少量添加剂并通过高温烧结来制备陶瓷坯体的方法，研究了原料配比和添加剂含量对烧结陶瓷坯体力学性能和显微结构的影响。结果表明，通过向球磨原料中添加聚乙烯醇(PVA)溶液可提高造粒粉的塑性，大幅提高花岗岩锯泥在坯体中的占比。高铝黏土可提升锯泥的烧结特性和成品的综合力学性能。其中，锯泥含量为80%(质量分数)、高铝黏土含量为20%(质量分数)的配方成品烧结温度为(1 160±30)℃,体积密度为2.43 g/cm³,吸水率为1%,弯曲强度为54 MPa,抗压强度为341 MPa,花岗岩锯泥利用率高且成本低，这为锯泥综合利用提供了一种高效的可行性方案。     

水分和粘结剂含量对坯体冷等静压成型和性能的影响

以Si粉(粒度≤0.044mm)和聚乙烯醇水溶液(PVA,其中聚乙烯醇质量份数为5%)按一定比例混匀,过筛造粒,振动装料后进行冷等静压成型,研究了水分和PVA含量对硅粉坯体成型和性能的影响。研究表明:当水分含量大于1wt%时,粉料填充密度低,填充不均匀,导致压制时压缩比大,压缩不均匀,坯体外形不规整;当水分在0.5～1wt%时,硅粉填充密度较大,粉料的成型性较好,粉料中水分含量确定为0.5～1wt%。当加入的PVA的量从5wt%增加到15wt%时,坯体强度随PVA含量增加而增加;当加入的PVA的量从15%wt增加到25wt%时,坯体强度有降低的趋势,而且坯体中存在残余颗粒团聚体;当加入的聚乙烯醇溶液质量份数为15wt%时,坯体强度最大(约1.62MPa),并且不存在残余颗粒团聚体,确定粘结剂含量为15wt%。     

添加剂对喷雾冷冻干燥MgAl2O4粉体性能的影响

以聚乙烯醇(PVA)和聚乙二醇(PEG)作为添加剂,采用喷雾冷冻干燥技术制备MgAl2O4造粒粉体.通过振实密度测量仪、扫描电镜、万能试验机等设备系统研究了不同PVA和PEG添加量下造粒粉体的流动性、颗粒形貌、粒径分布及颗粒强度等性能.通过粉体成型和烧结过程,分析了造粒粉体性能对素坯密度、微观结构和陶瓷光学质量的影响.结果 表明,添加PVA和PEG造粒粉体制备的素坯在预烧过程可以避免晶界大气孔的生成,有利于通过热等静压处理消除残余气孔.添加PEG样品的气孔尺寸较小,短波范围内的透过率提高.添加3wt％PVA和PEG造粒粉体制备的MgAl2O4透明陶瓷在400 nm波长处的透光率分别为76.3％和77.1％,明显高于无添加剂的样品.     

废玻璃降低日用陶瓷烧成温度的研究

研究废玻璃降低日用陶瓷烧成温度的可能性.以普通陶瓷坯料为基体,外加不同粒度的废玻璃并调整废玻璃的掺加量,经干燥成型制备坯体,干燥后在1100℃～1250℃烧结.通过测定吸水率、电子扫描电镜观察断面形貌确定其烧结程度及致密度,测试其强度进行比较.实验结果表明,陶瓷坯体掺入废玻璃不仅能降低烧成温度还能增加强度,添加9%、120目废玻璃粉的坯体强度增加16.73%.     

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。