改性羟基磷灰石高温湿敏元件的研究

本文探讨了化学共沉淀法合成改性羟基磷灰石反应温度、pH值、预烧温度和改性剂加入量对湿敏元件性能的影响。确定了合适的工艺条件,制造出的羟基磷灰石高温湿敏元件不仅可在常温下应用,而且在150℃高温下仍有优良的感湿性能。     

高分子材料电阻型湿敏元件光辐射预老化处理的实验与研究

采用了光辐射预老化处理高分子材料电阻型湿敏元件,并通过测量预处理湿敏元件前后的电阻值和长期跟踪测试来研究其性能变化。结果表明,被适当的光辐射如氦氖激光预老化处理湿敏元件的感湿特征量的长期稳定性变好了,其它性能变化不大。     

高分子材料电阻型湿敏元件的交流电激励预老化处理的实验与研究

采用了交流电激励老化法预处理高分子材料电阻型湿敏元件,并通过测量湿敏元件预处理前后的电阻值和长期跟踪测试来研究其性能变化。结果表明,被适当的交流电激励老化预处理的湿敏元件的感湿特征量的线性和长期稳定性变好了,其它性能变化不大。     

HDPE-AA-SSS预辐照接枝膜的表征及其湿敏性能的研究

采用预辐照法将亲水性单体丙烯酸(AA)和对苯乙烯磺酸钠(SSS)接枝到疏水性高密度聚乙烯(HDPE)薄膜上,制备出新型的接枝膜湿敏元件.通过扫描电镜观测了辐照接枝前和接枝后HDPE膜的表面形貌,并通过红外光谱表征了膜的结构,同时测定了接枝膜湿敏元件的湿敏性能.实验结果表明,制备的接枝膜湿敏元件具有良好的湿敏特性,响应和恢复时间短.它具有较好的稳定性,能在高湿、高温环境下使用.实验结果也表明了接枝HDPE膜具有良好的湿敏性能.     

TiO2-SnO2薄膜的湿敏性能研究

采用溶胶-凝胶工艺在印有梳状银电极的石英玻璃表面制备了不同含量Sn2+掺杂的氧化钛薄膜,通过烧结制得一系列湿敏元件,研究了Sn2+掺杂量、烧结温度和工作频率对薄膜湿敏性能的影响.研究表明,较低的工作频率下元件的湿敏性能较好;Sn2+的加入不同程度地降低了TiO2基薄膜的阻抗值,其中TiO2-15wt%SnO2薄膜表现出最高的灵敏度;薄膜高的湿敏性能与Sn2+掺杂引起的晶粒度变化以及热处理过程中的晶型转变有关.     

Al_2O_3湿敏元件的机理与动力学

本期刊1984年第二期,曾概要地介绍了Al_2O_3湿敏元件的发展历史、制作工艺、诸项有关的性能和定量校正的方法。本文将对A1_2O_3湿敏元件的湿敏机理和测湿动力学作一简要的说明,以期对A1_2O_3湿敏元件有一个比较完整的描述。我们已经知道,在Al_2O_3湿敏元件测湿时,外界气相湿度的变化,都会引起元件湿敏介质层中吸(附)水     

添加剂对ZrO_2-MgO系湿敏陶瓷湿阻性能的影响

本文研究了ZrO_2-MgO系湿敏陶瓷Zr/Mg比及添加剂对其湿阻性能的影响,摸索了有关配方和工艺。实验结果表明,提高Zr/Mg比,并引入某些M_2O_3(M为三价金属元素)外加剂对湿阻性能有利,但低温下元件的阻值仍较高。进一步添加外加剂如Li_2CO_3,可使湿阻性能得到改善。     

提高Nasicon湿敏元件的感湿灵敏度

采用MgO和Y_2O_3掺杂,磷酸二氢铵作发泡剂,使Nasicon湿敏元件的感湿灵敏度从2.0提高到4.O左右.实验结果证实了Nasicon材料半导化的设想.测定了Nasicon湿敏元件的气孔分布,对材料显微结构进行了讨论.     

纳米湿敏陶瓷α-Fe_2O_3-Al_2O_3-K_2O的制备与性能

采用溶胶—凝胶法新工艺制备了不同配比的纳米级α -Fe2 O3 -Al2 O3 -K2 O复合氧化物湿敏陶瓷。XRD、BET比表面吸附、Archimede排水法等手段对系列纳米陶瓷物相及微结构进行了分析表征。湿敏特性测试结果表明 :调控各组分摩尔配比为r(Fe∶Al∶K) =90∶5∶5,可获得全湿区阻—湿特性线性关系良好、感湿灵敏度较高、湿滞小、使用温度范围宽、响应速度较快、性能一致性优的湿敏元件。提出组份间界面作用模型 ,并初步探讨了影响材料阻—湿特性及湿滞的内在因素     

纳米湿敏陶瓷α-Fe2O-Al2O3-K2O的制备与性能

采用溶胶-凝胶法新工艺制备了不同配比的纳米级α-Fe2O3-Al2O3-K2O复合氧化物湿敏陶瓷.XRD、BET比表面吸附、Archimede排水法等手段对系列纳米陶瓷物相及微结构进行了分析表征.湿敏特性测试结果表明:调控各组分摩尔配比为r(Fe:Al:K)=90:5:5,可获得全湿区阻-湿特性线性关系良好、感湿灵敏度较高、湿滞小、使用温度范围宽、响应速度较快、性能一致性优的湿敏元件.提出组份间界面作用模型,并初步探讨了影响材料阻-湿特性及湿滞的内在因素.     

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。