石墨炉原子吸收法测定饱和氯化钠盐水中的钙镁

本文指出石墨炉原子吸收光谱法是一项测定氯化纳饱和盐水(大约300克/升)中钙、镁浓度的快速而又精确的方法,盐水中钙和镁的浓度范围分别为1～100μg/l和0.4～50μg/l。文章讨论了普通石墨管、热解涂层石墨管与原子化期间通过管子的氩气流量的不同组合对本分析方法的影响。     

涂钨热解石墨管——石墨炉原子吸收法测定痕量银

选择涂钨热解石墨管测银,按照最佳试验应用涂钨热解石墨管——石墨炉原子吸收法测定银,样品用HNO3进行溶解,进行测定。分析结果证实,用涂钨处理的石墨管提高了方法的灵敏度和精度。     

石墨炉原子吸收光谱法测定生活饮用水中微量钡的研究

研究了石墨炉原子吸收光谱法测定生活饮用水中微量钡的方法,确定了石墨管类型、最佳加热程序和最佳基体改进剂的测定条件。结果表明,选用热解涂层平台石墨管、硝酸镁为基体改进剂,灰化温度1 200℃,原子化温度2 500℃,其加标回收率为96.3%～103.6%,RSD<4.8%,基体改进剂的使用有效地降低了背景吸收,提高了背信比。该方法简便、快速,适用于生活饮用水中钡的测定。     

微波消解石墨炉原子吸收法测定土壤中痕量锡

建立了硝酸-氢氟酸-盐酸体系微波消解石墨炉原子吸收法测定土壤中痕量锡的方法。以硝酸镍和酒石酸为基体改进剂,热解涂层石墨管,塞曼效应扣除背景。该方法前处理操作过程简单,酸用量少,方法的最低检出质量分数为0.49μg/g(以取样质量0.250 0 g,定容体积50 m L计),样品的加标回收率为89.0%~96.0%。     

最新金属碳化物涂层石墨管技术及其应用

本文通过作层石墨管与普通石墨管应用的比较，得出金属碳化物涂层石墨管技术是一种操作简单并且实用的新型技术。     

高定向热解石墨的两相石墨化现象

高定向热解石墨中存在石墨相与部分石墨化碳相两相,本文对两相的基本特性和两相产生的机制进行了探讨,提出改变热解石墨的沉积参数,可以减少高定向热解石墨中两相的产生。     

热解温度对氧化石墨的结构与导电性能的影响

通过元素分析、X射线衍射分析、Fourier变换红外光谱仪和粉末电阻率测定探讨了不同热解温度处理的热解氧化石墨的化学组成、晶体结构和电导率随热解温度的变化规律.结果表明:氧化石墨的热解过程可分为3个阶段:第Ⅰ阶段即热解温度低于180 ℃时,热解氧化石墨仍维持着氧化石墨的层状有序结构,但层间距迅速减小,电导率逐渐增加;第Ⅱ阶段即热解温度在180～500℃之间时,热解氧化石墨的晶体结构由氧化石墨态经由过渡态逐渐向类石墨态转变,当热解温度为500℃时完全转化为类石墨态,电导率达到最大值;第Ⅲ阶段即热解温度在500～1 000℃之间时,热解氧化石墨的晶体结构为类石墨态,相比原石墨存在明显的晶粒细化现象,电导率也随着热解温度的上升而逐渐降低.     

热解石墨的形貌结构及缺陷

通过扫描电子显微镜观察了热解石墨的表面和断面形貌及显微组织结构，分析了热解石墨中各种缺陷形成的原因，探讨了沉积工艺参数对热解石墨显微组织结构的影响。     

石墨炉原子吸收法检测食品中铝的方法优化

对石墨炉原子吸收法测食品中铝的方法进行了优化,包括消解方式和程序升温条件.结果表明,选择热解涂覆石墨管,灰化温度700℃、原子化温度2400℃作为仪器条件,有效提高石墨管寿命,对食品中的铝进行测定,曲线相关系数>0.995,加标回收可达到90％～110％,准确性好,重复性较好.该方法具有较高的实用价值和学术价值,对测定食品中铝具有一定的指导意义.     

热解石墨涂层外延基座的工艺与性能

一、序言 七十年代初科学院一0九厂用我所涂层的热解石墨基座再包硅,而后在外延中应用,取得了单片基座使用寿命两年之久的好结果。但因多种原因工作未能继续。1976年,我们根据对外延工艺的了解和国内外延基座存在的问题,即:“硅外延片几乎都有雾点,二极管和三极管的制管成品率很低”的状况,推荐使用热解石墨涂层外延基座,首先在辽阳第一晶体管厂进行试用,同时逐渐推广到全国务研究单位和半导体厂。经过一段时间的验证,普遍反应效果良好,使用寿命长,并制得了经铬酸腐蚀液处理后表面     

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。