双波长分光光度法测定电镀废水中微量锌

在阿拉伯树胶存在下,在pH 5.7 HAc-NaAc缓冲溶液中,Zn(Ⅱ)与硫氰酸钾和中性红(NR)反应生成稳定的离子缔合物[NR]4[Zn(SCN)6],使NR退色,在462 nm处出现正吸收峰,575 nm处出现负吸收峰.选定测定波长为462和575 nm,建立了双波长光度法测定微量锌.结果表明:锌含量在0.0～1...     

原子吸收法测定代森锌和福美锌

文章建立了代森锌和福美锌含量的原子吸收测定方法。代森锌和福美锌在酸性热溶液中分解,通过非吸收线法确定不存在非特征衰减,在锌元素共振吸收波长213.9 nm下测定样品溶液中锌元素含量,用锌元素换算得到代森锌和福美锌含量。实验结果表明,该方法的测定代森锌标准偏差为0.0017,变异系数为1.49%,平均回收率为99.3%,...     

二甲酚橙光度法测定葡萄糖酸锌中锌含量

在pH=5~6弱酸性条件下,锌和二甲酚橙反应形成稳定的橙红色配合物,最大吸收波长为568 nm,锌含量在0~2.5μg/mL范围内与吸光度呈良好的线性关系。方法用于测定葡萄糖酸锌中锌含量,结果满意。     

原子吸收光谱法测定丙森锌

采用原子吸收光谱法测定丙森锌的含量。试样分别经酸分解硝化处理和水提取,在213.9nm波长下,测定其总锌和无机锌的含量,并由总锌与无机锌之差值乘以丙森锌对锌的换算系数计算出试样中丙森锌的含量。实验结果表明,该方法的平均回收率为98.8%~100.7%,相对标准偏差为0.82%。     

原子吸收法测定铅锌混合精矿中的铅和锌

主要探讨用原子吸收分光光度计在铅、锌的次灵敏线上分别测定铅锌混合精矿中的高含量的铅、锌的方法。经过实验得知在铅的次灵敏线波长为λ=368.4 nm,锌在次灵敏线的波长λ=307.6 nm处测得的铅、锌的吸光值符合测试要求,并且测得的铅锌混合精矿中的铅、锌的含量和用容量分析法测得的铅、锌的含量在允许的误差范围内。也就是说用原子吸收分光光度计测得的铅锌混合精矿中的铅、锌的结果是准确可靠的。     

用原子吸收法连续测定钢丝帘线镀层中的铜锌含量

采用原子吸收法对钢丝帘线镀层中的铜、锌含量进行连续测定。试验结果表明,原子吸收法测定铜、锌含量的最佳条件为,狭缝宽度0.5nm,乙炔流速0.9L·min-1,空气流速11L·min-1,燃头高5(刻度值),波长分别为324.7和213.9nm,灯电流分别为3和6mA。在此条件下常见的几种共存离子对测定几乎无干扰,且测定结果标准偏差小。     

电热板消解分光光度法测定土壤中锌的含量

以电热板-混酸法对土壤样品进行预处理,用锌试剂作显色剂,分光光度法检测土壤中锌的含量。实验中探索了锌试剂与锌离子反应的最佳实验条件,即最大吸收波长为620nm,反应时间为3min,缓冲溶液用量为1.00m L,锌试剂用量为0.15m L。测定结果显示本实验中土壤样品中的锌含量为58.8mg/kg,回收率范围为98%~102%,相对标准偏差为2.10%。该方法使用仪器简单,操作方便迅速,可以用于土壤中锌离子的测定,结果满意。     

胭脂红褪色光度法测定锌镍合金镀液中的镍含量

在pH=5．4的六次甲基四胺一盐酸缓冲溶液、100℃恒温水浴中,Ni^2 能催化双氧水氧化胭脂红褪色,据此提出采用胭脂红褪色光度法测定锌镍合金镀液中的镍含量。确定了适宜的试验条件,其中测定波长为518nm。讨论了该镍催化反应的表观活化能以及杂质离子对测定结果的影响,并给出了某电镀厂碱性锌镍合金镀液中镍含量的测定结果。该方法简便,准确度高,能满足生产中快速测定的要求。     

酸性氯化物锌-钴合金镀液中锌钴的测定

首先利用酸性镀液中钴本身的颜色，以水作参比，在波长为520nm处，直接用分光光度法测定Co^2 含量，然后，在pH=5.5的条件下，以二甲酚橙作指示剂，用EDTA滴定锌钴求出锌钴合量，再用锌钴合量减去镀液中的钴含量从中得到锌的含量。方法简单快速，测量结果准确，能满足实际生产要求。     

微波消解-电感耦合等离子体发射光谱法测定土壤中铜锌铅镍铬

用微波消解法对土壤进行消解后,采用电感耦合等离子体发射光谱（ICP-AES）法测定土壤中铜锌铅镍铬的含量。铜锌铅镍铬的测定波长分别在324.754nm、206.200nm、182.205nm、341.476nm、283.563nm时,在0～10mg/L浓度范围内曲线线性良好,相关系数在0.9993～0.9998、检出限在1～3mg/kg、测定下限在4～12mg/kg之间。土壤铜锌铅镍铬加标回收率均在88.2～102.2之间、RSD(n=6)低于5%。该方法快速便捷、重现性好、准确度高,可用于测定土壤中的铜锌铅镍铬。     

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。