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91.
Soybean plant volatiles, extracted as steam distillates, significantly affected the behavior and biology of the cabbage looper,Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae). Distillates from the susceptible Davis variety attractedT. ni larvae and female adults, whereas those from resistant PI 227687 plants repelled them. When mixed in an artificial diet, steam distillates from PI 227687 plants caused mortality of first-instar larvae. Adults emerging from pupae topically treated with 5 g of such PI 227687 extractable showed developmental abnormalities. Larval feeding was significantly less on Davis leaves treated with PI 227687 volatiles as compared to solvent (acetone) or such Davis extractables. However, Davis volatiles on PI 227687 leaves did not increase larval feeding. HPLC analyses of steam distillates from susceptible Davis versus resistant PI 227687 indicated differences. 相似文献
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The objective of this study was to determine how the fracture of adhesive joints depends on elastic beam parameters describing the adherends and the applied loads. The basic specimen geometry was the cracked lap shear joint constructed of aluminium alloy with various adherend and bondline thicknesses. Loads were applied in different combinations of bending, tension and shear to generate a failure envelope for each adhesive and specimen geometry. It was found that crack propagation for precracked specimens occured at a critical strain energy release rate but was also a function of the GI/GII ratio and the bondline thickness. The experiments also showed that the loads required to propagate a crack in a precracked specimen were always lower than the loads required to break the fillet. Hence, by treating uncracked joints as being cracked, where the fictitious crack tip is assumed to coincide with the location of the fillet, a conservative estimate of the failure load is obtained. 相似文献
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96.
煤的荧光特性与其工艺性能的关系研究 总被引:1,自引:0,他引:1
简述了煤中镜质组荧光产生的机理及荧光参数的测量方法,通过测定一系列煤的粘结性和10kg小焦炉结焦性试验,探讨了煤的荧光特性与其工艺性能的关系。煤的荧光参数与其反射率呈正的线性相关关系,与其挥发分含量呈负的线性相关关系;煤的粘结性、结焦性均与其荧光参数有关;当煤化程度相同、煤岩组成基本相同时,煤的荧光强度愈强,其结焦性能愈好。 相似文献
97.
当今计算机技术的快速发展,使得计算机病毒的智能性日益突出,所以使用单一的传统检测技术在病毒检测过程中,漏检和误检的比例明显上升。为了应对目前病毒体现出的智能性,反病毒技术也必须采用相应的智能技术。文中在查阅了相关资料后,提出一种基于粒子群的病毒检测技术。首先对一个未知属性的程序依照病毒的属性来判断该程序是否是病毒程序。在确定该程序是病毒的前提条件下,再通过粒子群的方法来判断该病毒所属种类。 相似文献
98.
Trygve Burchardt Pascal GouérecEmilio Sanchez-Cortezon Zia KarichevJames H Miners 《Fuel》2002,81(17):2151-2155
ZeTek Power recently introduced mass manufacturable and cost effective alkaline fuel cells on the market. Today's research is focused on further improvement both in terms of performance increase and cost reduction. This research is classically performed using small (4 cm2) experimental electrodes in the half-cell configuration. This allows the primary electrochemical losses in an anode or cathode to be determined independently. Additional performance losses occur when one integrates large electrodes into a module of 24 cells and in a stack comprised of many modules. By comparing the performance of half-cell experiments to that of modules, these losses can be distinguished and addressed. The information thus obtained, both for the small electrodes and in up-scaling is vital if one is to identify the key areas in which improvement is possible and where to focus future research. Furthermore, the identification of the losses in a module and system allows us to predict the final performance from half-cell measurements of a new laboratory scale experimental electrode. 相似文献
99.
The activity and molecular weights of glutathioneS-transferase were studied in three species of cereal aphid:Metopolophium dirhodum, Sitobion avenae, andRhopalosiphum padi. The highest level of glutathioneS-transferase activity was recorded in extracts fromM. dirhodum and the lowest fromS. avenae, and extracts of larvae were more active than those from adults. The activity of this enzyme was higher in extracts ofS. avenae andR. padi previously fed on a moderately resistant wheat variety than on a susceptible variety. Gel filtration followed by SDS-PAGE revealed three protein bands in the active fractions. The first had a molecular weight of 28,500 and the second of 27,500 and were present in all three species of aphid. The third protein differed in the three species, having a molecular weight of 26,000 inS. avenae, 25,500 inM. dirhodum, and 24,000 inR. padi. 相似文献