三诺西与次氯酸钠预氧化效果对比研究

该文采用一种新型的消毒剂(三诺西)对某水厂原水进行预氧化试验研究,考察了三诺西在预氧化过程中对藻类、叶绿素、细菌等去除效果,并与水厂现有预氧化剂次氯酸钠对比预氧化性能。结果表明,三诺西在水中有效成分衰减缓慢,可以保持水中稳定的残余有效成分浓度,具有持续的氧化能力,对叶绿素a去除效果较好,优于次氯酸钠去除效果,但对藻类和细菌去除效果不及次氯酸钠。     

高锰酸钾和氯氧化对水库原水三维荧光峰及藻类活性影响

针对水库藻类和有机污染一直困扰饮用水安全的重大问题,分别采用高锰酸钾和氯两种预氧化法,考察两种氧化剂对典型水库原水中藻类和有机物的氧化效果及其影响因素。从藻类光合活性和叶绿素a含量的角度对两种氧化剂除藻的效果进行比较。在合适的氧化剂投加范围之内次氯酸钠对藻细胞活性的抑制要远远优于高锰酸钾。氯氧化对藻类的杀灭作用较为剧烈,且可以在短时间内有效抑制藻类的生长;而高锰酸钾的氧化作用较弱,即使在较高的投加量下也需要充足的反应时间才能使藻类活性降低。高锰酸钾对原水中藻类的去除除了氧化破坏藻细胞的作用以外,其还原中间态二氧化锰能对藻细胞产生吸附架桥的作用,从而可降低藻细胞在水中的数量。     

预氧化强化混凝去除富营养化水体中藻类研究回顾

水体富营养化导致的水华威胁着饮用水安全和水生态平衡。近年来,如何高效地去除水中的藻类已成为国内外的研究热点。将预氧化和混凝法进行联用可以起到协同效果,从而有效去除水体中的藻类,而不同的预氧化方法在除藻机理、效果上均有很大差别。文中主要探讨了高锰酸钾、臭氧、二氧化氯、高铁酸盐、紫外预氧化强化混凝除藻时的不同特性、效果以及安全性,为水厂除藻工艺的选择提供参考。     

微藻对混凝除藻效率的影响及改善措施

考察了富营养化水体中微型藻对混凝除藻效率的影响，以及控制“混凝-过滤”工艺出水中微藻的措施。微型藻含量增加会降低混凝除藻效率，因此微型藻的存在决定了混凝除藻效率的限度。微型藻大量存在时，预氧化可以改善混凝除藻的效率。增加过滤深度可以显著提高微型藻的去除效率，活性炭深度处理也可以有效地去除水中的微型藻。因此，决定富营养化源水除藻难易程度的主要因素是源水中藻类生物的种群结构，而不是叶绿素值。源水中藻类生物的种群结构决定了水厂除藻工艺的选择。加强水源水保护，生态调控优化源水中藻类生物种群结构是解决水厂除藻问题的根本途径。     

夏季滦河水预氧化中试研究

本试验通过对比两种预氧化剂对夏季滦河水的藻类、CODMn、UV254、TOC等指标的去除效果，分析水中分子量的分布情况，研究了高锰酸钾和氯预氧化对有机物的去除效果。结果表明，KMnO4预氧化在去除有机污染物方面的效果要好于预氯化的处理效果；高锰酸钾预氧化的UV254去除率为23．4％，而TOC去除率为7．1％，说明一部分UV吸收性有机物在预氧化过程中转变为UV非吸收陛有机物，低高锰酸钾投量条件下水中有机物不能得到完全去除。     

氧化-混凝工艺处理碱性含砷废水的试验研究

研究了用氧化与混凝组合工艺处理某锑冶炼厂排放的碱性含砷废水。研究结果表明,聚合硫酸铁较三氯化铁、硫酸亚铁对原水中砷的去除效果好;用氧化与混凝组合工艺较单纯用混凝工艺对砷的去除率高：双氧水、次氯酸钠这两种氧化剂中采用次氯酸钠氧化对原水中砷的去除效果及处理成本最佳。     

预氧化对饮用水常规处理除藻的影响

以微污染水库水为原水，臭氧、过氧化氢、高锰酸盐复合药剂、紫外光及其不同组合作为预氧化剂，进行了预氧化对藻类影响的试验研究。试验结果表明，预氧化能够不同程度地改善常规处理对饮用水中藻类的去除效果。本试验中，臭氧、臭氧和过氧化氢、臭氧和高锰酸盐复合药剂、紫外光照四者对藻类的最高去除率分别是：     

响应面法优化水力空化——次氯酸钠氧化大肠杆菌的工艺

以大肠杆菌作为水中微生物的指示细菌,采用水力空化-次氯酸钠强化氧化技术去除水中微生物,考察了入口压力、次氯酸钠含量、空化时间等因素对水中大肠杆菌的去除效果,并用响应面分析方法对实验结果进行分析和参数优化。结果表明,大肠杆菌初始含量为5.0×10~6 CFU/m L、水温为30℃时,水力空化-次氯酸钠强化氧化消毒工艺的优化参数为:入口压力0.37 MPa、Na Cl O的质量浓度6.0 mg/L、空化时间38 min,在此条件下所得大肠杆菌去除量的对数为4.96,与模型的预测值相近,说明采用响应面优化得到的工艺参数可靠。     

高锰酸钾预氧化强化混凝工艺对高藻水的处理

该文考察了高锰酸钾预氧化对高藻水源水中污染物的去除效果,结果表明高锰酸钾预氧化-混凝沉淀工艺对高藻水中污染物的去除效果比单独混凝沉淀工艺更好.高锰酸钾预氧化工艺的优化结果表明当高锰酸钾最优投加量为1.0 mg/L、混凝剂聚合氯化铝投加量为30 mg/L时,该组合工艺对藻类、藻毒素、嗅味、UV254、DOC及三卤甲烷生成势的去除率分别为83.57％、87.89％、100％、44.3％、45.45％和64.4 ％.     

预氧化剂对北江原水DBPs前体物去除的影响

模拟水生产流程,研究不同氧化剂预氧化对北江原水消毒副产物(DBPs)前体物去除的影响。结果表明:当高锰酸钾投加量为1.5 mg/L时,COD_(Mn)的去除效果最佳,去除率最高可达51.38%;投加高锰酸钾、二氧化氯可以提高UV_(254)说的去除率;采用次氯酸钠作为预氧化剂,氯与原水中的有机污染物直接反应生成DBPs;氧化剂二氧化氯可以有效去除三氯乙醛前体物,且随着投加量的增加,三氯甲烷去除率也随之增加;当高锰酸钾投加量达到1.5 mg/L时,三卤甲烷(THMs)总量达到最低,此时三氯甲烷及THMs去除率达到30%以上。从水质安全考虑,建议以北江原水为水源的水厂采用高锰酸钾或二氧化氯替代预氯化工艺。     

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.     

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。     

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.