国内外高纯无机盐指标对比及杂质检测方法

随着高新技术领域的快速发展,对高纯无机盐的需求日益增加。高纯无机盐中杂质元素的存在,会不同程度地影响其应用性能,因此需对杂质离子含量进行严格限制并准确检测。仪器分析在产品纯度测定、所含杂质物质的种类和含量测定等方面具有不可替代的作用。以高纯硝酸银为例,对比了国内外无机盐产品的技术指标和分析检测方法,进一步对高纯无机盐中痕量杂质的检测方法,主要包括原子吸收光谱法和电感耦合等离子体光谱法进行了综述。     

ICP-OES法测定高纯磷酸盐中金属杂质

通过盐酸对高纯磷酸盐的处理后,利用等离子体发射光谱法对其中Co﹑Cr﹑Mn﹑Ni﹑Ti微量金属杂质进行了检测,方法回收率为82.4%～117.6%,相对标准偏差为0.12%～4.06%,该方法操作简单,可准确测定高纯磷酸盐中金属杂质,在实际生产中能满足生产分析需求。     

电子工业用高纯化学品动向

在电子元件生产过程中使用的高纯化学药品主要用于洗净、蚀刻、光刻胶、显像、剥离、扩散等方面,其中主要用于印刷线路工艺,因此,对可能会影响电性能的金属杂质和对印刷线路有害的微粒要求极严。不仅要求在生产过程中除去金属杂质和微粒,而且要求在运输和贮存时避免二次污染。电子工业用的高纯化学药品有时即使只含ppb等级的极微量的金属杂质也会影响产品质     

气体中微量水和氧分析方法的国外概况

在集成电路、半导体器件、电真空器件及电子材料的生产中,广泛应用各种高纯气体。这些气体有氧气、氮气、氢气、氩气、氦气……等,以及它们的混合气。各种高纯气体在各道工序中都直接同器件或零件接触。例如半导体器件、集成电路生产中的外延、扩散工序,硅片在高温下同氢气、氮气和氧气直接接触,因此所使用气体的纯度和各种杂质含量直接影响电子产品的质量和成品率。在各种杂质中,水分和氧是两种主要的十分有害的杂质,对其     

四氟化碳中痕量气体杂质的气相色谱分析

采用配有放电离子化检测器的气相色谱仪分析高纯四氟化碳中痕量气体杂质。研究了分析四氟化碳中氧气、氮气、一氧化碳、二氧化碳和六氟化硫等气体杂质的操作参数,确定了高纯四氟化碳中痕量气体杂质的分析方法。     

高纯氟化氢中微量杂质气体测定

采用气相色谱分析系统,建立了一种精准测定高纯氟化氢(HF)中微量杂质气体的方法。以高纯氦为载气,高纯HF经专用除水装置除水、预分离柱分离、反吹处理,气体杂质通过分子筛柱和Hayesep柱分离后进入氦放电离子化检测器(DID),用外标法定量分析微量杂质组分H_2、O_2+Ar、N_2、CH_4、CO和CO_2,体积分数检出限可达10~(-8),相对标准偏差(RSD)5%。该方法准确、可靠、精密度好,能够精准检测HF气体中的微量气体杂质。     

四氟化硅气体中杂质的检测及净化研究进展

介绍了四氟化硅气体中杂质的4种检测方法:气相色谱法、红外光谱法、气相色谱质谱法、原子发射光谱法。其中,气相色谱法一般用来测定四氟化硅气体中的烃类杂质,红外光谱法主要用来测定四氟化硅气体中的氟硅烷、氟氧硅烷、氟硅醇杂质。气相色谱质谱法用来测定四氟化硅气体中的六氟化硫杂质,原子发射光谱法主要用来测定四氟化硅气体中的金属杂质。然后对四氟化硅气体的不同净化方法进行列举,并对净化工艺的条件、优缺点进行了阐述。     

四氟化硅气体中杂质的检测及净化研究进展

介绍了四氟化硅气体中杂质的4种检测方法:气相色谱法、红外光谱法、气相色谱质谱法、原子发射光谱法。其中,气相色谱法一般用来测定四氟化硅气体中的烃类杂质,红外光谱法主要用来测定四氟化硅气体中的氟硅烷、氟氧硅烷、氟硅醇杂质。气相色谱质谱法用来测定四氟化硅气体中的六氟化硫杂质,原子发射光谱法主要用来测定四氟化硅气体中的金属杂质。然后对四氟化硅气体的不同净化方法进行列举,并对净化工艺的条件、优缺点进行了阐述。     

PPB级高纯氮生产的工艺设计及其技术特点分析

随着互联网时代的到来,电子、多晶硅等行业广泛兴起,高纯气体的需求越来越多,高纯氮气在电子、多晶硅等行业的应用越来越广泛。制取氮气的基本方法是将空气分离,一般利用氮、氧的沸点不同其分离,常用深度冷冻法。随着高纯气体的纯度要求越来越高,对气体中的杂质含量要求越来越严格,常需在制氮之前对原料气设置纯化装置进行纯化。本工艺的目的在于克服现有技术中的不足,提供一种适用于PPB级高纯氮生产的吸附装置及具有其的纯化器。在实施时,原料空气流经各吸附层后能够实现一次纯化即可有效去除原料空气中的H_2O杂质、CO杂质、CO_2杂质,而无需安装后纯化器进行再次纯化。纯化器可实现吸附和解吸之间相互切换,保持吸附活性,以保证吸附效果。     

工业四氯化硅四级精馏的研究

高纯四氯化硅是热氢化、催化氢化、等离子氢化、光纤生产的原料,其品质要求达到9N。在改良西门子法生产多晶硅过程中,副产物工业四氯化硅,其中的各项金属杂质,硼磷杂质含量较高,并且含有高聚物,硅粉。采用常规的精馏法,吸附法,易出现堵塞,采用络合法,易出现络合剂分离不开的问题。通过采用四级精馏,一级脱重,去除其中的高聚物和大量的金属杂质,二级再脱重,去除金属杂质,回流采出轻组分,侧线采出产品,进入三级脱轻塔,去除其中的三氯氢硅,塔釜依靠压差,进入四级脱重塔,塔顶得到高纯四氯化硅产品。四级精馏得到的高纯四氯化硅,避免外杂质的引入,易得到9N产品。     

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。