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61.
以水溶性聚合物聚乙烯醇(PVA)和水不溶性聚合物乙酸乙烯-乙烯共聚物(VAE)乳液为原料,采用溶液共混法制备了PVA-VAE共混膜,为农药成膜剂的制备开辟了新途径。红外光谱、透射电镜、激光粒度仪测试结果显示,PVA溶液中的胶束被打开,体系的比表面积急剧增大,两相间的界面消失,说明共混体系分子间具有良好的相容性;透水性与耐水性测定结果表明,PVA-VAE的质量比为80∶ 20、70∶ 30、60∶ 40时其共混膜的性能适用于农药种衣剂的成膜剂;种子发芽试验显示,与单独使用PVA膜相比,引入适当比例VAE后的共混膜用于种子包衣,其耐水性显著提高,渗水率适宜,对种子发芽无明显影响。 相似文献
62.
农药微乳剂浊点是微乳剂的主要质量技术指标之一。研究了3种不同种类农药的微乳剂组份与浊点的关系,并利用17O-核磁共振(17O-NMR)方法对其机理进行了探究。研究表明:浊点与表面活性剂、助表面活性剂与水之间形成的氢键强度成正相关;随着水质硬度的上升,浊点下降。建议选用亲水性强的表面活性剂和极性较强的助表面活性剂来配制微乳剂,同时为了节约成本和便于工厂生产,可采用自来水来配制农药微乳剂,而采取其他措施来提高农药微乳剂的浊点。 相似文献
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昆虫病原线虫的贮存和剂型研究进展 总被引:3,自引:0,他引:3
阐述了昆虫病原线虫的贮存原理,介绍业已建立的昆虫病原线虫贮存方法及其优缺点,影响昆虫病原线虫贮存效果的主要因素,并讨论了昆虫病原线虫剂型制备方法。 相似文献
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66.
1,3‐Dichloropropene (1,3‐D), which consists of two isomers, (Z)‐ and (E)‐1,3‐D, is considered to be a viable alternative to methyl bromide, but atmospheric emission of 1,3‐D is often associated with deterioration of air quality. To minimize environmental impacts of 1,3‐D, emission control strategies are in need of investigation. One approach to reduce 1,3‐D emissions is to accelerate its degradation by incorporating organic amendments into the soil surface. In this study, we investigated the ability of four organic amendments to enhance the rate of degradation of (Z)‐ and (E)‐1,3‐D in a sandy loam soil. Degradation of (Z)‐ and (E)‐1,3‐D was well described by first‐order kinetics, and rates of degradation for the two isomers were similar. Composted steer manure (SM) was the most reactive of the organic amendments tested. The half‐life of both the (Z)‐ and (E)‐isomers in unamended soil at 20 °C was 6.3 days; those in 5% SM‐amended soil were 1.8 and 1.9 days, respectively. At 40 °C, the half‐life of both isomers in 5% SM‐amended soil was 0.5 day. Activation energy values for amended soil at 2, 5 and 10% SM were 56.5, 53.4 and 64.5 kJ mol?1, respectively. At 20 °C, the contribution of degradation from biological mechanisms was largest in soil amended with SM, but chemical mechanisms still accounted for more than 58% of the (Z)‐ and (E)‐1,3‐D degradation. The effect of temperature and amendment rate upon degradation should be considered when describing the fate and transport of 1,3‐D isomers in soil. Use of organic soil amendments appears to be a promising method to enhance fumigant degradation and reduce volatile emissions. Published in 2001 for SCI by John Wiley & Sons, Ltd 相似文献
67.
The uncalibrated predictive ability of four preferential flow models (CRACK‐NP, MACRO/MACRO_DB, PLM, SWAT) has been evaluated against point rates of drainflow and associated concentrations of isoproturon from a highly structured and heterogeneous clay soil in the south of England. Data were available for four plots for a number of storm events in each of three successive growing seasons. The mechanistic models CRACK‐NP and MACRO generally gave reasonable estimates of drainflow over the three seasons, but under‐estimated concentrations of isoproturon over a prolonged period in the first season and over‐estimated them in the two remaining seasons. CRACK‐NP simulated maximum concentrations of isoproturon over the first two events of each of the three seasons of 156, 527 and 24.4 µg litre?1, respectively, and matched the observed data (465, 65.1 and 0.65 µg litre?1) slightly better than MACRO (69.1, 566 and 58.5 µg litre?1). Automatic selection of parameters from soils information within MACRO_DB reduced the emphasis on preferential flow relative to the stand‐alone version of MACRO. This gave a poor simulation of isoproturon breakthrough and simulated maximum concentrations were 0, 50.1 and 35.1 µg litre?1, respectively. The capacity model PLM gave the best overall simulation of total drainflow for the first two events in each season, but over‐estimated concentrations of isoproturon (967, 808 and 51.3 µg litre?1). The simple model SWAT represented total drainflow reasonably well and gave the best simulation of maximum isoproturon concentrations (140, 80.2 and 8.2 µg litre?1). There was no clear advantage here in using the mechanistic models rather than the simpler models. None of the models tested was able to simulate consistently the data set, and uncalibrated modelling cannot be recommended for such artificially drained heavy clay soils. © 2001 Society of Chemical Industry 相似文献
68.
超临界流体萃取技术在农药残留分析中的应用进展 总被引:12,自引:2,他引:12
从萃取过程控制的角度,综述了近几年来国外超临界流体技术不同形态的基体的农药残留分析中的应用情况、研究现状及前景。 相似文献
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70.
The pest control potential demonstrated by various extracts and compounds isolated from the kernels and leaves of the neem plant (Azadirachta indica) A. Juss. (Meliaceae) seem to be of tremendous importance for agriculture in developing countries. Laboratory and field trial data have revealed that neem extracts are toxic to over 400 species of insect pests some of which have developed resistance to conventional pesticides, e.g. sweet potato whitefly (Bemisia tabaci Genn. Diptera: Aleyrodidae), the diamond back moth (Plutella xylostella L. Lepidoptera: Plutellidae) and cattle ticks (Amblyomma cajennense F. Acarina: Ixodidae andBoophilus microplus Canestrini. Acarina: Ixodidae). The compounds isolated from the neem plant manifest their effects on the test organisms in many ways, e.g. as antifeedants, growth regulators, repellents, toxicants and chemosterilants. This review strives to assess critically the pest control potential of neem extracts and compounds for their use in the tropics. This assessment is based on the information available on the wide range of pests against which neem extracts and compounds have proven to be toxic, toxicity to non-target organisms, e.g. parasitoids, pollinators, mammals and fish, formulations, stability and phytotoxicity. 相似文献