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41.
Short syntheses of (Z)-7-dodecen-1-yl acetate, (Z)-7-tetradecen-1-yl acetate, (Z)-9-dodecen-1-yl acetate, and (Z)-9-tetradecen-1-yl acetate from 7-hydroxyheptanal and 9-oxononanoic acid precursors obtained by oxidative cleavage of easily available aleuritic acid are reported. The key step in these syntheses is a stereoselective Wittig reaction between aldehyde and alkyl-phosphonium salt. Wittig-Horner type reaction of 7-hydroxyheptanal and diethyl cyanomethylphosphonate gave the ,-unsaturated nitrile derivative which after protection of the hydroxyl group was reduced to the corresponding aldehyde. Wittig reaction of the latter, followed by acetylation, completed the synthesis of (E,Z)-7,9-dodecadien-1-yl acetate, the sex pheromone of the European grapevine mothLobesia botrana Schiff. 相似文献
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欧志芳 《网络安全技术与应用》2014,(12):72-72
面对复杂多变的需求,需要我们梳理出业务的本质,并设计一套与之相适应、易扩展的框架结构,让业务组件化,组件服务化,通过灵活的服务组装,来满足灵活多样的业务需求。本文旨在通过对中国电信CEP协议的剖析,指引如何通过对整个CEP层次结构进行归纳总结,体系化实现服务能力的封装与开放。 相似文献
44.
Experiments were conducted to (1) determine whether the electroantennogram (EAG) can detect differences among the responses of antennae from males derived from the three strains ofOstrinia nubilalis (Hübner), and (2) characterize the EAG responses of each strain to isomeric forms of the natural pheromone, (E)- and (Z)-11-tetradecen-1-ol acetate (TDA), and analogs possessing differences in the terminal alkyl group, cyclopropyl (CPA), ortert-butyl (TBA).EAG responses differed among the strains in two ways: (1) Antennae fromZZ males always produced an EAG to (Z)-TDA with an extended duration of response. This signature EAG response was found to be unique to the antennal response ofZZ males to (Z)-TDA, thus providing a relatively easy method of distinguishing liveZZ males fromEE orZE males. Correlated with this longer EAG response was a longer disadaptation time, i.e., the EAG response ofZZ antennae disadapted more slowly (ca. 10 min) than the response ofEE antennae. (2) Strain differences in the relative EAG amplitudes to isomers and analogs were observed at the stimulus amounts eliciting the peak EAG amplitude as follows: TDA CPA > TBA forZZ males and both isomers; TDA > CPA TBA and CPA TDA > TBA forEE males and theE andZ isomers, respectively; CPA > TBA TDA forZE males and both isomers. Dose—response relationships were seen for all compounds if amplitude (peak height) of the EAG was used as a measure of response. However, if width of the EAG at half the peak height (peak width) was used, then only theZZ antennal response to (Z)-TDA resulted in a meaningful dose-response relationship. For all strains, the EAG amplitudes elicited by theZ isomers of any of the tested compounds were greater than those elicited by the correspondingE isomers. Therefore, correlations between the relative EAG and upwind flight responses were observed in theZZ (r = 0.86) andZE (r = 0.80) strains but were not correlated in theEE strain (r = 0.18). Temporal studies showed that adaptation, not postexcision deterioration, was responsible for the observed decreases in the EAG amplitude after repetitive stimulation or after stimulation with amounts in a descending order. Disa-daptation required at least 20 min for a moderate dose (10 g for 1 sec). Developmental studies showed that antennae from 2-day-old adults had the greatest EAG response. 相似文献
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F. Campos J. Atkinson J. T. Arnason B. J. R. Philogène P. Morand N. H. Werstiuk G. Timmins 《Journal of chemical ecology》1989,15(7):1989-2001
2,4-Dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA), the major hydroxamic acid present in corn, and its tritiated derivative, were prepared synthetically for use in the determination of the toxicokinetics of this insect deterrent in the European corn borer (ECB),Ostrinia nubilalis. In growth studies with DIMBOA (0, 0.05, 0.2, and 0.5 mg/g diet), the mean time to pupation and adult emergence were significantly lengthened by an increase in concentration. Pupal and adult weights, for both female and male, decreased with an increase in concentration. Increased larval and pupal mortality occurred at the highest concentration of DIMBOA. DIMBOA, at concentrations of 0.2 and 0.5 mg/g diet, resulted in a decrease in the number of egg masses produced per female, and at 0.5 mg/g diet, in a decrease in the number of eggs per egg mass. Larvae fed from the neonate stage on a diet containing 0.2 mg [3H]- + [1H]DIMBOA/g diet showed an increase in the content of label from fourth to fifth instar, but levels declined at pupation and emergence. A large amount of the labeled compounds was excreted by the insect in the pupal case. In dose-related studies, both uptake and excretion increased with an increase in concentration of DIMBOA (0.05, 0.2, 0.4 mg/g diet), while a body burden (concentration in the tissues/concentration in the frass) of approximately 0.25 was maintained for all concentrations. At the highest dose of DIMBOA (0.4 mg/g), the ECB increased consumption, possibly to compensate for the toxic effects of the compound. In topical application studies, elimination of the labeled compound in the frass was rapid, reaching 65% by 4 hr and 88% by 48 hr. Accumulation of label in tissues other than hemolymph was low. The results show that the ECB does possess adaptive mechanisms to deal with the effects of this host-derived compound. 相似文献
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评价了国内外成品油管道技术现状和发展趋势。基于中亚、中俄跨国管道迅速发展,国内已开展中国和俄罗斯标准差异研究,但在成品油管道运行领域较少涉及,为此选取了俄罗斯有代表性的成品油管道综合性标准。该标准的先进性主要体现在以下几个方面:油品排列原则更为细化、采用工艺混油缓冲塞和限定控制初始工艺混油以减少混油、规定成品油管道最低允许流速、严格控制混油切割浓度、基于定量计算掺混比例进行混油掺混作业等。最后,针对完善我国成品油管道运行标准提出了建议。 相似文献
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比较了JB/T 4730-2005《承压设备无损检测》和SY/T 4109-2005《石油天然气钢质管道无损检测》两个标准射线部分的不同之处,包括射线源和能量的选择、透照次数、底片质量和质量分级等方面,便于无损检测工作者更好地理解标准和准确地使用标准,从而保证无损检测工作质量和工程焊接质量。 相似文献
49.
摘介绍ISO3452—3:1998标准及依据该标准而制订的相应国家标准的主要内容,包括渗透检验用标准试块的类型、尺寸和制作方法,以使我国无损检测工作者能更好地了解和采用该标准所规定的渗透检验试块。I型试块适用于确定荧光和着色渗透剂系统的灵敏度等级,Ⅱ型试块适用于评定荧光和着色渗透检验的综合性能,它们可有效保证渗透检验结果的可靠性,已被欧美日等发达国家广泛采用。 相似文献
50.
超声衍射时差法探伤和定量技术--焊缝超声检测最新欧洲标准介绍 总被引:6,自引:4,他引:6
超声衍射时差(TOFD)法是焊缝超声检测和缺陷定量很有发展前景的新技术。它根据入射纵波在缺陷端部产生的衍射波传播时差进行测深定高,是一种可靠性甚高的方法,有A,D,B三种显示方式,探伤结果记录较直观和客观。根据最新欧洲标准(草案)ENV583 6:2000的有关规定,介绍超声TOFD技术应用要领,企望该技术在国内无损检测(NDT)领域迅速推广应用。 相似文献