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991.
Michail V. Kozlov Junwei Zhu Peter Philipp Wittko Francke Elena L. Zvereva Bill S. Hansson Christer Löfstedt 《Journal of chemical ecology》1996,22(3):431-454
The fifth abdominal segment of femaleEriocrania semipurpurella (Stephens) andE. sangii (Wood) contains a pair of exocrine glands. Hexane extracts of this segment were prepared from both species and analyzed by gas chromatography with simultaneous flame ionization and electroantennographic detection (EAD). For both species, the EAD active peaks were identified as nonan-2-one, (Z)-6-nonen-2-one, and (Z)-6-nonen-2-ol by means of mass spectrometry and comparison of retention indices with those of synthetic standards. Enantiomeric separation of chiral alcohols from the female extracts was achieved by gas chromatographic analysis on a cyclodextrin column. InE. semipurpurella, a mixture of (2S,6Z)-nonen-2-ol and (2R,6Z)-nonen-2-ol (2: I) was found, whereas inE. sangii (2S,6Z)-nonen-2-ol was the predominant enantiomer and only traces of theR enantiomer were indicated by the antennal response. In field tests, a blend of the three compounds was not attractive to conspecific males. A subtractive assay showed that the alcohol in various enantiomeric mixtures was the only attractive compound, whereas addition of (Z)-6-nonen-2-one to the alcohol completely inhibited the attraction of both species. A trapping experiment including a wide range of ratios between theR andS enantiomers showed that baits containing 95–100% of theS enantiomer were attractive to maleE. sangii, whereas males ofE. semipurpurella were attracted to all tested ratios of the enantiomers. However, the response profiles of maleE. semipurpurella differed between populations from southern Sweden, south Finland, and the Kola Peninsula in Russia. In south Sweden males were maximally attracted to a racemic mixture of the alcohols. At the Kola PeninsulaE. semipurpurella was attracted to baits containing 95–100% of theR enantiomer. In south Finland all tested ratios between 0 and 100%R enantiomer trappedE. semipurpurella, but the trap catches appeared to be bimodally distributed with peaks around 15 and 70%R enantiomer. The trapping results suggest the existence of pheromone races or sibling species among the specimens identified asE. semipurpurella.Dedicated to Prof. H. J. Bestmann on the occasion of his 70th birthday. 相似文献
992.
993.
Relationship of structure to properties of surfactants. 16. Linear decyldiphenylether sulfonates 总被引:1,自引:0,他引:1
Milton J. Rosen Zhen Huo Zhu Xi Yuan Hua 《Journal of the American Oil Chemists' Society》1992,69(1):30-33
The properties of some well-characterized sodium linear decyldiphenylether (C10DPE)sulfonates have been studied. Among the properties investigated are dynamic and equilibrium surface tension, critical
micelle concentration (CMC), area per molecule at the aqueous solution/air interface, wetting time by the Draves technique,
foaming by the Ross-Miles method, solubilization, and hydrotropy. The decyldiphenylether moiety appears to be equivalent to
a terminally substituted straight alkyl chain of 16 carbon atoms. The trialkyl- and dialkyl-mono-sulfonates have solubilities
of < 0.01 g/dm3 in water, but are readily soluble in hexane. The didecyldiphenyl ether disulfonate (DADS) has a very low CMC value (1.0 ×
10−5 mol dm−3) in aqueous 0.1 N Na+ solution (NaCl), characteristic of surfactants with two hydrophilic and two hydrophobic groups. It also has a much larger
area per molecule at the aqueous solution/air interface than the monodecyldiphenyl-ether monosulfonate (MAMS) and a much higher
surface tension at the CMC. MAMS has a much lower surface tension at a surface age of 1 second (γ1s) than either DADS or the monodecyldiphenylether disulfonate (MADS). In agreement with γ1s and γeq values, wetting times increase in the order: MAMS < DADS < MADS and initial foam heights decrease in the order: MAMS > DADS
> MADS. Solubilization for three water-insoluble surfactants decreases in the order: DADS > MAMS > MADS, while hydrotropy
is most pronounced with the disulfonates. 相似文献
994.
In this paper, we propose a new hard problem, called bilateral inhomogeneous small integer solution (Bi-ISIS), which can be seen as an extension of the small integer solution problem on lattices. The main idea is that, instead of choosing a rectangle matrix, we choose a square matrix with small rank to generate Bi-ISIS problem without affecting the hardness of the underlying SIS problem. Based on this new problem, we present two new hardness problems: computational Bi-ISIS and decisional problems. As a direct application of these problems, we construct a new lattice-based key exchange (KE) protocol, which is analogous to the classic Diffie- Hellman KE protocol. We prove the security of this protocol and show that it provides better security in case of worst-case hardness of lattice problems, relatively efficient implementations, and great simplicity. 相似文献
995.
焙烧高岭土的结构特征和吸附性能 总被引:5,自引:0,他引:5
通过对焙烧高岭土的矿物特性和表面吸附性质的研究。用化学分析,XRD、IR、XPS、Raman光谱和SEM观察证明焙烧高岭土的羟基基团完全消失,等温吸附,粒度分布试验证明焙烧高岭土水化能力较大,但吸附能力较弱。 相似文献
996.
Ke Xu Min Zhu GuangWu Hu Liang Zhu YiFeng Zhong Ying Liu JianPing Wu Ning Wang 《中国科学:信息科学(英文版)》2014,57(11):1-24
There is a general consensus about the success of Internet architecture in academia and industry. However, with the development of diversified application, the existing Internet architecture is facing more and more challenges in scalability, security, mobility and performance. A novel evolvable Internet architecture framework is proposed in this paper to meet the continuous changing application requirements. The basic idea of evolvability is relaxing the constraints that limit the development of the architecture while adhering to the core design principles of the Internet. Three important design constraints used to ensure the construction of the evolvable architecture, including the evolvability constraint, the economic adaptability constraint and the manageability constraint, are comprehensively described. We consider that the evolvable architecture can be developed from the network layer under these design constraints. What's more, we believe that the address system is the foundation of the Internet. Therefore, we propose a general address platform which provides a more open and efficient network environment for the research and development of the evolvable architecture. 相似文献
997.
当今的网络在设计初期并没有充分考虑其安全性,因此使得网络被频频攻击成功。当网络管理人员在检测网络是否遭到黑客的攻击时,可以从网络流量的角度出发,检测网络流量是否异常。网络流量是否异常可以作为网络是否被攻击的一个依据。网络中的流量存在正常还是异常的两种状态,在参考已有的检测技术之后,使用MMTD这一算法来检测网络的流量。在文中根据流与流量的特性给出检测函数y=f(x),最后使用MMTD这一算法进行流量是否异常做出判断。利用MMTD算法来研究网络的流量尚属第一次,该算法能够使得已有流量检测算法具有一定的智能性,可以作为已有流量检测算法的补充。 相似文献
998.
根据军工企业信息化工作的实际情况,结合军工企业办公应用和安全应用需求,帮助企业进行业务梳理、系统架构和安全特性设计,实现了适合军工企业办公特色,在涉密网络环境应用的安全增强协同办公系统。通过部署实施和使用,系统较好地满足了企业安全化和专业化的办公管理需求,提高了企业办公效率和企业核心竞争力。 相似文献
999.
Efficient and selective oxidation of primary and secondary alcohols to the corresponding aldehydes and ketones catalyzed by potassium permanganate supported on Kieselguhr reagent under solvent free conditions are reported. 相似文献
1000.
通过开展技术攻关,开发、采用在线反吹、"波动法"除垢、高效阻垢剂、在线检测与专家诊断系统等乙烯装置长周期运行技术,解决了裂解炉对流段超温、急冷油塔和裂解气压缩机结垢、乙炔前加氢反应器稳定性差等影响长周期运行的技术难题,实现了乙烯装置连续运转6年,创国内乙烯装置长周期运行新纪录,达到国际先进水平. 相似文献