不同清洗剂对蔬菜残杀威农药的洗涤效果研究

探讨不同洗涤剂对蔬菜上农药的洗涤效果,以得到生活中健康有效的洗涤方式。分别采用清水,食盐水、Na2CO3溶液、Na HCO3溶液、淀粉溶液、洗洁精溶液对油麦菜上残杀威农药进行清洗,然后测定残留农药的含量。结果显示,Na2CO3溶液,洗洁精溶液洗涤效果优于其他几种,但洗洁精容易残留,对身体健康产生影响。因此对用Na2CO3溶液洗涤进行进一步研究,探讨不同洗涤时间和温度下10. 0 g/L Na2CO3溶液的洗涤效果,实验结果表明,洗涤时间30 min和45℃时效果最好。     

不同清洗剂对蔬菜中毒死蜱残留的洗涤效果研究

探讨不同浓度的清洗剂在不同时间对蔬菜中毒死蜱残留的洗涤效果,得到日常生活中简便易行的去除蔬菜农残的方法。分别采用食盐水、Na HCO3、洗洁精、淀粉、清水对生菜中的残留毒死蜱进行清洗,然后用高效液相色谱测定农药的含量。实验结果显示,在洗涤时间为5min时,食盐水、Na HCO3、洗洁精、淀粉、清水对生菜中残留毒死蜱的去除率分别为76%、51%、55%、36%和13%。在洗涤时间为10 min时,上述五种清洗剂对毒死蜱的去除率分别为77%、54%、76%、49%和18%。在洗涤时间为15 min时,上述五种清洗剂对毒死蜱的去除率分别为80%、62%、82%、43%和22%。     

蔬菜中农残分析方法及残留农药去除率的研究

建立了一种气相色谱法检测蔬菜中农药残留的测定方法,考察了自制果蔬洗涤盐对蔬菜农药残留的去除率。采用基质固相分散法处理蔬菜样品,弗洛里硅土为固相吸附剂,丙酮/正己烷为洗脱液,各农药回收率在78%~107%,检出限0.003~0.006 mg/kg,定量限0.02~0.03 mg/kg,相对标准偏差小于8%。此方法简单、易操作,可用于评价各类洗涤剂去除农药的效果。为有效去除蔬菜表面残留的农药,以食盐为基本原料,通过复配表面活性剂制备出高效的果蔬洗涤盐,其对有机磷农药敌敌畏、乐果、毒死蜱的去除率在70%~94%,蔬菜中农药残留量均低于国家最高残留限量。     

不同清洗方式对百菌清等3种杀菌剂残留的去除效果

研究清水冲洗和不同浸泡时间对茄子上百菌清、三唑酮、异菌脲残留的去除效果。百菌清由于非内吸性、水溶性差,以清水冲洗效果最好;三唑酮由于内吸性、水溶性好,浸泡时间越长越有利于农药的去除;异菌脲虽然为非内吸性、水溶性差,但是其制剂为悬浮剂,利于在茄子表面吸附,因而去除效果相对较差。比较3种杀菌剂在茄子上的去除效果,为三唑酮>百菌清>异菌脲。     

蔬菜中农药残留的去除方法

蔬菜中的农药残留问题成为现今人们关注的热点,文中对去除蔬菜残留农药的各种方法进行了综述。日常使用的普通方法如去皮、储藏、烹饪、洗涤等,以及需要特殊仪器或者试剂的方法,如臭氧处理等都可以不同程度地去除残留在蔬菜上的农药。对于番茄、黄瓜等果菜类蔬菜,去皮可以除掉大部分残留;而菠菜、白菜等叶菜类蔬菜,用沸水清洗效果最好。     

蔬菜中违禁农药残留状况分析

基于深圳最大的蔬菜农批市场,选取快速检测结果为阳性的蔬菜8406批次开展农药残留定量检测试验.结果发现检出违禁农药项目占比为0.972%,在上海青、小白菜、菜心、豇豆、包芥菜等检出农药比例较高,而对硫磷、甲基异柳磷、克百威、灭多威、氟虫腈、毒死蜱等违禁农药残留项目检出率偏高。应采取有效措施,加强蔬菜的监督管理,从源头禁止高毒农药的使用,加大蔬菜种植、销售环节的监测,确保市民食用蔬菜的安全。     

处理方式对蔬菜中拟除虫菊酯类农药残留的影响

人们食用的蔬菜中残留一定的农药,如果在清洗过程中不将这些农药残留去除,对人体带来不良影响。因此为研究不同处理方式对蔬菜中拟除虫菊酯类农药残留的影响,从某农贸市场选取蔬菜样品进行实验。     

不同配比碱金属化合物对焦炭反应性的影响

通过将一定粒度焦炭浸入不同配比碱金属化合物（K2CO3＋Na2CO3）溶液的方法在实验室制得焦样,用热重天平对焦样进行了焦炭反应性实验及SEM扫描电镜和能谱分析。研究结果表明,不同配比碱金属K、Na复合催化剂催化效果不同,K2CO3对焦炭溶损反应的催化作用贡献较大,焦炭溶损反应主要催化作用时间为前10min,浸碱焦炭试样中K、Na含量随碱溶液中K、Na含量增加而增加。     

微乳型果蔬清洗剂去除农药残留的研究

研究了微乳型果蔬清洗剂对蔬菜表面农药残留的清除效果。向青菜表面喷洒含有乙酰甲胺磷、氧乐果、敌百虫、氯氟氰菊酯的混合农药,并于喷洒后第3天、7天、14天、21天分别进行采集,再采用微乳型果蔬清洗剂、市售去除农残果蔬专用清洗剂和自来水分别清洗。测定青菜中4种农药的残留量,评估3种清洗剂对不同农药、喷洒农药后不同采收时间农残的清除效果。研究结果表明:随着喷洒农药采收时间的延长,青菜中4种农残均有不同程度的降低;但清洗效率明显下降。微乳型果蔬清洗剂对4种农药均有很好的去除效果,对喷洒后第21天采收的青菜中4种农药的平均去除率达63.90%,而市售果蔬清洗剂和自来水的平均去除率仅为44.88%和20.76%。鉴于微乳型果蔬清洗剂良好的增溶性和渗透性,适合于蔬果表皮内部以及疏水性农药残留的去除。     

纳米ZnO/SnO2复合光催化剂的制备研究

研究ZnO/SnO2复合催化剂的合成,考察ZnO/SnO2前驱体在不同Zn/Sn反应剂量的摩尔比、不同沉淀剂Na2CO3与总金属离子溶液的体积,以及不同反应时间条件下制备的复合催化剂对甲基橙光催化降解效果的影响。研究表明,当Zn/Sn反应剂量的摩尔比为9∶1,沉淀剂Na2CO3与总金属离子溶液的体积比为2∶1,反应时间为10min时制取的复合催化剂前驱体对甲基橙的光催化降解效果最好,降解30min甲基橙溶液的脱色率可达96.00%以上。     

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.