玻碳电极的物理预处理方法

用循环伏安技术研究了玻碳电极在 K3 Fe( CN) 6和肾上腺素体系中的电化学性能 ,证实了用 Si C打磨玻碳电极的物理预处理方法的可行性。实验结果表明 ,在预处理玻碳电极上 ,K3 Fe( CN) 6在 0 .5mol/L KCl中的电还原反应为可逆反应 ,肾上腺素在 0 .5mol/L H2 SO4 介质中的电氧化反应为准可逆反应 ,其异相电子转移速率常数为 1 .0 7× 1 0 -2 cm/s     

杯芳烃修饰主客体化学传感器研究--对甲酚的测定

以C-十-烷基间苯二酚杯(6)芳烃作为主体分子,修饰于玻碳电极上,制成的一种主客体化学传感器.并用其对溶液中的客体分子--对甲酚进行测定.该电极具有良好的选择性,对5.0×10-5～2.0×10-3mol·L-1的对甲酚具有很好的线性响应.检测下限为3.0×10-5mol·L-1.同时,对修饰前后玻碳电极的表面状态进行了研究.     

杯芳烃修饰主客体化学传感器研究——对甲酚的测定

以C—十一烷基间苯二酚杯 (6 )芳烃作为主体分子 ,修饰玻碳电极上制成的一种主客体化学传感器 ,并用其对溶液中的客体分子———对甲酚进行测定。该电极具有良好的选择性 ,对 5 .0× 10 -5～2 .0× 10 -3 mol/L的对甲酚具有很好的线性响应 ,检测下限为 3.0× 10 -5mol/L ,同时对修饰前后玻碳电极的表面状态进行了研究     

碳纳米管修饰电极对抗坏血酸的电催化性能研究

采用循环伏安法研究了碳纳米管修饰玻碳电极对抗坏血酸的电催化活性。研究表明,碳纳米管修饰玻碳电极对抗坏血酸具有优异的电催化活性,与裸玻碳电极相比,抗坏血酸在该修饰电极上的氧化峰电位负移0.502 V,氧化峰电流增加78%;抗坏血酸浓度在1.0×10-5～0.1 mol/L范围内呈良好线性关系,最低检测限为1.0×10-6 mol/L。     

电活化玻碳电极循环伏安法测定对苯二酚的研究

研究简化电极处理过程测定环境水样中对苯二酚含量的效果。以电活化的玻碳电极为工作电极,采用循环伏安法测定环境水样中对苯二酚的含量。结果表明,电活化的玻碳电极对对苯二酚的氧化还原反应有明显的电催化作用,对苯二酚的氧化还原峰电流与其浓度在1×10~(-6)~1×10~(-4)mol/L范围内呈现良好的线性关系。电活化的玻碳电极具有良好的重现性,用该方法测定了环境水样中对苯二酚的含量,回收率为93.8%~103.6%,结果令人满意。从而建立一种简便、快速、准确的测定环境中对苯二酚含量的方法。     

乙二醇的电化学分析方法研究

本文制备了介孔碳/纳米铂复合材料修饰玻碳电极,并采用循环伏安法研究了乙二醇在该电极上的电化学行为,与乙二醇在裸玻碳电极上的电化学行为进行相应的对比,发现乙二醇在修饰电极上的氧化峰电流较大,且氧化峰电势电位较低,表明乙二醇在该修饰的电极上具有良好的电催化氧化效应。乙二醇在浓度范围为1.0×10~(-5)~1.0×10~(-3)mol/L之间与峰电流ip呈良好的线性关系,据此建立了乙二醇的电化学分析方法,可用于实际样品中乙二醇的测定。     

对氨基苯酚的分离精制

研究了对氨基苯酚(PAP)的萃取提纯技术,它适用于硝基苯催化加氢还原液的分离。研究了溶剂种类。pH值、温度、相比等因素对萃取过程的影响。对萃取使用过的溶剂采用精馏的方法进行回收,从而获得了适合于医药用的高纯度对氨基苯酚(PAP),其关键杂质4,4’-二氨基二苯醚含量低于10×10~(-6)。     

预处理玻碳电极线性扫描伏安法测定槲皮素的研究

运用循环伏安法、线性扫描伏安法等测试技术研究了槲皮素在预处理玻碳电极上的电化学行为,建立了一种直接测定槲皮素的电化学分析方法。结果表明,与裸玻碳电极相比,预处理玻碳电极能显著提高槲皮素的氧化峰电流。在优化的实验条件下,氧化峰电流与槲皮素浓度在1.0×10-7～2.0×10-5mol/L范围内呈良好的线性关系,最低检测限为6.2×10-8mol/L。该方法简便、快捷、准确、灵敏度高。本法用于芦丁水解产物槲皮素的测定,效果良好。     

电活化玻碳电极循环伏安法测定对苯二酚的研究

研究简化电极处理过程测定环境水样中对苯二酚含量的效果。以电活化的玻碳电极为工作电极,采用循环伏安法测定环境水样中对苯二酚的含量。结果表明,电活化的玻碳电极对对苯二酚的氧化还原反应有明显的电催化作用,对苯二酚的氧化还原峰电流与其浓度在1×10^(-6)(-6)¹×101×10^(-4)mol/L范围内呈现良好的线性关系。电活化的玻碳电极具有良好的重现性,用该方法测定了环境水样中对苯二酚的含量,回收率为93.8%(-4)mol/L范围内呈现良好的线性关系。电活化的玻碳电极具有良好的重现性,用该方法测定了环境水样中对苯二酚的含量,回收率为93.8%¹03.6%,结果令人满意。从而建立一种简便、快速、准确的测定环境中对苯二酚含量的方法。     

一步法电沉积制备纳米金/碳纳米管修饰电极及对邻苯二酚电催化性能研究

以羧基化碳纳米管(CNT-COOH)溶液作为支持电解质,采用多电位阶跃电沉积方法将CNTs和纳米金同步直接沉积到玻碳电极表面,制备了对邻苯二酚(CAT)具有很高的电催化氧化作用的纳米金-碳纳米管修饰电极(Au/CNTs/GCE),其催化效果强于单独的金纳米粒子或碳纳米管修饰电极。通过优化沉积时间、pH和扫速对修饰电极的影响,并考察了在最佳条件下CAT在Au/CNTs/GCE修饰电极上的电化学行为,发现CAT在该修饰电极上发生可逆的氧化还原反应,响应电流与浓度在4.0×10-6～8.0×10-5mol/L和1.0×10-4～1.0×10-3mol/L范围内呈线性关系,相关系数分别为0.9996和0.9985,检出限为4.5×10-7mol/L(S/N)。     

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。