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1.
The effects of the cuticle and epicuticular waxes of grapefruit, strawberry and apple on the photodegradation and penetration of chlorpyrifos-methyl were studied. Photodegradation experiments were conducted by exposing the insecticide to the light of a xenon lamp in the presence of a film of wax extracted from the fruit surface. The half-life of chlorpyrifos-methyl irradiated in absence of waxes was 9.6 min. The half-lives of pesticide irradiated in the presence of wax extracts of apple, grapefruit and strawberry were 83, 34 and 26 min, respectively. In penetration studies, fruit with and without wax layers were treated with an aqueous suspension of pesticide. The penetration of the pesticide from the cuticle to the pulp was measured after 24 h. Samples without wax contained a higher total amount of insecticide than those with wax. No pesticide was detected in samples of apple and grapefruit pulp. Residues were detected in all fractions of strawberry. The waxes and cuticle appear to have some effect on the photodegradation and penetration of chlorpyrifos-methyl in fruit samples. 相似文献
2.
钨铜合金药型罩及其性能 总被引:3,自引:0,他引:3
钨铜合金药型罩的应用可以提高射流对均质钢靶的侵彻能力.这一提高得益于射流密度的提高以及断裂时间的延长. 本文对钨铜合金射流及其断裂形态通过X光照像进行了研究.它的旋转效应及其炸高特性也进行了实验研究. 钨铜合金药型罩的威力实验在φ30 mm的破甲弹上进行.在相同装药条件下与紫铜罩相比,威力提高20~30%. 相似文献
3.
Hyun Kyu Suh 《Fuel》2008,87(6):925-932
This paper investigates the effect of injection parameters on the characteristics of dimethyl ether (DME) as an alternative fuel in a diesel engine with experimental and analytical models based on empirical equations. In order to study macroscopic and microscopic characteristics of DME fuel, this work focuses on the atomization characteristics of DME and compares experimental and predicted results for spray development obtained by empirical models for diesel and DME fuel. Detailed comparisons of spray tip penetration from three different empirical correlations and from visualization experiments of diesel and DME fuels were conducted under various fuel injection conditions. In comparison with the results of different empirical equations for measured spray tip penetration, the experimental results of this study provide good agreement with the calculation results based on empirical equations, except during the earliest stage of the injected spray sequence. The results of atomization characteristics indicate that DME showed better spray characteristics than conventional diesel fuel. Also, the fuel injection delay and maximum injection rate of DME fuel are shorter and lower than those of diesel fuel at the same injection conditions, respectively. 相似文献
5.
Alekseevskii-Tate revisited:An extension to the modified hydrodynamic theory of long rod penetration
LAN Bin & WEN HeMing CAS Key Laboratory for Mechanical Behavior Design of Materials University of Science Technology of China Hefei China 《中国科学:信息科学(英文版)》2010,(5)
The modified hydrodynamic theory of long rod penetration into semi-infinite targets was established independently by Alek-seevskii and Tate over forty years ago and since then many investigators contributed much to the development of the high speed penetration mechanics.However,in all the models proposed so far,the target resistance Rt is not well defined and usually determined by adjusting it until the predicted depth of penetration comes to an agreement with experimental data.In this paper,assumptions are... 相似文献
6.
This authors of this article investigated the dynamic response of woven Kevlar®29/epoxy laminates subjected to the impact loading. The cylindrical aluminum foam projectile and steel projectile were used to exert the impulse on the laminates. Deformation/failure modes, deflections, strain histories, and failure mechanisms were obtained and discussed. The results showed that with the high toughness of Kevlar fiber, the deformation modes of the laminates exhibited some characteristics similar to the metal panel, such as large global deformation. The failure mechanisms like matrix failure, fiber splitting, and fibrillation were observed. These micron failures led to the macroscopic delamination and fracture of the laminates. 相似文献
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借助气相色谱基本原理,实验测定了全氟二甲基环丁烷大气示踪剂通过Carboxen-569碳分子筛吸附管的穿透体积和大气样品采集的安全采样体积。结果表明:示踪剂的穿透体积(VB)与温度(t)满足lgVB=4.525-0.041 2t关系,而与流动相的流速(F)变化(F≤1 500 mL/min)基本无关;示踪剂样品安全采样体积(VS)与采样温度的关系为lgVS=4.551-0.061 6t(F=1 000 mL/min),与流动相流速的关系为lgVS=2.195-2.449×10-4F(t=40℃)。常温采样时,示踪剂的采样损失可以忽略。 相似文献
10.
活性炭共吸附现象对有机蒸气穿透容量的影响 总被引:3,自引:0,他引:3
在空气避有机蒸气的气相色谱分析方法研究中,为获得可靠的采样效果,探讨了活性炭对共存有机蒸气的共吸附与穿透容量的关系,试验了四种有机蒸气共存时和组分的有采样效率。结果表明,共吸附使所有共存有机蒸气的穿透容量下降,共吸附物质愈多,穿透窝量下降愈严重。对二种和四种有机蒸气的共吸附,使丙酮的穿透容量下降21.9%和41.7%,四组分共存时,丙酮,丁酮,环已酮、甲苯的穿透窝量分别为5.6、5.0、9.7、1 相似文献