水泥中硫的高频红外分析方法研究

采用高频红外吸收法测定了水泥中硫的含量,并对样品作测定前的预处理(物理处理),在测定中选用复合型助熔剂,解决了高频感应炉中因顶吹氧气流的作用而导致的样品喷溅问题。该法可准确测定水泥中0.001％～5％的硫,回收率为98.6％～102.5％,RSD为0.78％～1.35％。     

高频感应-红外吸收法测定碳化硅中的SiC含量

文章采用碳化硅和基准碳酸钙混合配耐成不同含量的标准样品,对高频红外碳硫分析仪进行多点校正,通过测定碳化硅中的碳含量,换算得到碳化硅含量.该方法简便、快速,可适用于测定50%～90%范围的碳化硅含量.     

高频红外碳硫仪测定流化床触体中的碳含量

建立了采用高频红外碳硫仪测定流化床触体样品中碳含量的方法。通过向流化床触体样品中加入纯铁、锡粒和钨粒助熔剂,促进样品中的碳完全燃烧,采用高频红外碳硫仪测定燃烧生成的CO2的特征吸收峰的强度变化,通过朗伯-比尔定律间接测定样品中的碳含量。研究了样品用量、助熔剂的种类及用量对测试结果的影响。结果表明,在样品加入量为0.1 g、纯铁助熔剂0.2 g、锡助熔剂0.15 g、钨助熔剂1.5 g条件下,测试流化床4个床层高度触体样品的碳含量,测定结果的相对标准偏差均小于3%,加标回收率达到101.6%。该方法操作简单易行,适合于对流化床触体进行中控质量检测。     

碳纤维中碳含量测定方法的研究

碳纤维中碳含量是该类产品在进出口环节能否准确进行商品归类的重要依据.文章通过高频红外碳硫分析仪法和重量法对同一碳纤维样品进行测定,并比较试验过程和测试结果,从而选定高频红外碳硫分析仪法作为简单、快速、准确地测定碳纤维中碳含量的方法.     

高频燃烧红外吸收法测定氮化硼中碳

对高频燃烧红外吸收法测定氮化硼中的碳含量进行了研究。依据氮化硼的材料性质和高频燃烧红外吸收分析方法的分析特点,分别针对样品的称样量、助熔剂的种类及用量、校准曲线的建立、回收率等做了条件实验。最终得出最佳的实验条件是称取0.03~0.04g氮化硼样品,加入一定量的纯铁和钨锡助熔剂。按照最佳实验方法,对氮化硼中碳含量进行测定,结果的标准偏差(RSD,n=5)小于4%,对一个氮化硼实际样品进行回收试验,回收率为99%和105%。     

碳氮分析仪测定造纸法再造烟叶中的碳酸钙含量

建立了碳氮分析仪法测定造纸法再造烟叶中碳酸钙含量的方法。通过热催化高温氧化反应对样品进行消解,检测经高温分解产生的CO_2气体,分别用不同的前处理方法,测定样品中的总碳和有机碳,用差量法计算出无机碳后,依据碳和碳酸钙分子量的换算,计算得出样品中碳酸钙的含量。结果显示:①待测液线性响应对应的最高碳含量为36mg;②样品本底碳量为14.5mg时,当加标碳量分别为2.5、5.0、7.0mg时平行检测3次的变异系数分别为7.60%、6.25%、3.77%;③方法的回收率范围为85.96%～111.16%;④方法的检出限和定量限分别为0.013mg和0.04mg。方法适合于测定造纸法再造烟叶中碳酸钙的含量。     

基于高频燃烧红外法测定飞灰和炉渣碳含量的研究

使用高频燃烧红外吸收法对飞灰和炉渣进行碳含量测定的研究.通过试验和分析发现,当飞灰和炉渣碳含量在1％～15％,样品称样量在0.15 g±0.05 g,分别加入助熔剂:纯铁0.3～0.5 g,钨粒1.3～1.8 g时,测定出来的碳含量结果准确且精密度高,该方法能够替代经典法——利比西法.     

离子色谱法测定尿素中硫酸铵含量

建立离子色谱法测定尿素中硫酸铵含量的分析方法。该方法将尿素样品在250℃灼烧1 h后能分解80%的尿素且不影响硫酸根的稳定性,大大减少了有机物对色谱柱的污染,然后采用离子色谱仪测定样品中硫酸根离子浓度。硫酸根离子质量浓度在10～50 mg/L范围内线性良好,相关系数为0.999 8,方法检出限为0.001 mg/L,定量限为0.01 mg/L,测定结果的相对标准偏差为0.04%～0.05%(n=6),样品加标回收率为101.8%～104.7%。该方法能够将样品中大部分尿素除去,减少杂质的干扰,可用于尿素中硫酸根离子含量的测定。     

分光光度法测定乙酸仲丁酯生产过程中总铬

用高氯酸和硝酸湿法消解乙酸仲丁酯工艺中各种类型的样品,用二苯碳酰二肼（DPC）分光光度法测定其中的总铬含量。总铬含量在0～200 ppm范围内线性良好,线性方程为y=-0.002＋0043x,r=0.9996。样品测定结果相对标准偏差3.5%～4.5%,加标回收率95%～105%。与电感耦合等离子体原子发射光谱（ICP-AES）比较,结果一致。     

煤炭直接液化产品中氯含量测定

采用高温裂解燃烧/离子色谱法建立了测定煤直接液化产品微量氯含量分析方法。样品在高温裂解燃烧炉燃烧,其中氯化合物生成HCl气体或Cl2,经水吸收形成含Cl-的水溶液,离子色谱测出水溶液中的Cl-含量,进而计算出样品中的氯含量。优化的测定条件:燃烧炉温度1300℃,燃烧时间10 min,载气流速1.5 mL/min,样品进样量为0.10～0.16 g。2种不同添加量加标样品的平均回收率为106.61%和94.82%,分析结果的相对标准偏差为3.24%和0.18%。通过对多种煤直接液化产品氯含量分析,获得了煤液化产品中氯含量分布信息。     

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。