Azoperoxide. VI. Selektive Spaltungen von β-Azo-acylperoxiden

Azoperoxides. VI. Selective Decomposition of β-Azoacylperoxides The selective decomposition of the O O-Groups in the azoperoxides 1 and 2 is possible by reaction with dimethylaniline at 35°C. Rate constants were measured and the decomposition products were analyzed. Intermediates are azoalkyl radicals. The radical yield of the amine induced decomposition of 2 in ethylbenzene is 8.2% at 35°C. UV irradiation of the azoperoxides 1 and 2 at 20°C in ethylbenzene results in a quantitative and selective decomposition of the azo groups. Intermediates are C-radicals with intact peroxide groups. The reaction of 1 and 2 with triethylstannane yields reduction products of the O O-groups and the NN-groups, respectively.     

Cellulose Aerogel Fibers Tested on a REXUS 18 Rocket – The ACTOR Project

Aerogels are high‐performance materials used for space and aviation purposes. Cellulose aerogel fibers have been investigated under real space conditions for their insulation properties. The experiments were carried out in a one‐stage high‐altitude research rocket of the improved ORION type. A cuboid module with measurement cells, camera modules, and electronic devices has been developed for monitoring the insulation behavior of cellulose aerogel non‐woven samples. The thermal behavior of these samples has been analyzed and compared to cellulose cloth (cotton) and aluminum for reference.     

Male pheromone of swift moth,Hepialus hecta L. (Lepidoptera: Hepialidae)

(R)-6-Ethyl-2-methyl-2,3-dihydro-4H-pyran-4-one, (1R,3S,5R)-3-ethyl-1,8-dimethyl-2,9-dioxabicyclo[3.3. 1]non-7-ene, and (1R,3S,5R)-3-ethyl-1,8-dimethyl-2,9-dioxabicyclo[3.3.1]non-7-en-6-one represent the main components in the male pheromone of the swift moth,Hepialus hecta. The amounts of the three components were 40, 5, and 5 g per male, respectively. Structure elucidation of the compounds was based on spectroscopic data as compared to synthetic reference samples. The absolute configurations were determined by gas chromatography on chiral stationary phases; optically active samples served as reference compounds. Electrophysiological and behavioral experiments with natural material and synthetic samples clearly showed the three heterocyclic compounds to act as pheromones. (E, E)--Farnesene represents the main component of the scent secretion of maleHepialus humuli.     

Cuticular Hydrocarbons as Sex Pheromone of the Bee <Emphasis Type="Italic">Colletes cunicularius</Emphasis> and the Key to its Mimicry by the Sexually Deceptive Orchid, <Emphasis Type="Italic">Ophrys exaltata</Emphasis>

Male Colletes cunicularius bees pollinate the orchid, Ophrys exaltata, after being sexually deceived by the orchid’s odor-mimicry of the female bee’s sex pheromone. We detected biologically active volatiles of C. cunicularius by using gas chromatographic–electroantennographic detection (GC-EAD) with simultaneous flame ionization detection. After identification of the target compounds by coupled gas chromatography–mass spectrometry (GC-MS), we performed behavioral tests using synthetic blends of the active components. We detected 22 EAD active compounds in cuticular extracts of C. cunicularius females. Blends of straight chain, odd-numbered alkanes and (Z)-7-alkenes with 21–29 carbon atoms constituted the major biologically active compounds. Alkenes were the key compounds releasing mating behavior, especially those with (Z)-7 unsaturation. Comparison of patterns of bee volatiles with those of O. exaltata subsp. archipelagi revealed that all EAD-active compounds were also found in extracts of orchid labella. Previous studies of the mating behavior in C. cunicularius showed linalool to be an important attractant for patrolling males. We confirmed this with synthetic linalool but found that it rarely elicited copulatory behavior, in accordance with previous studies. A blend of active cuticular compounds with linalool elicited both attraction and copulation behavior in patrolling males. Thus, linalool appears to function as a long-range attractant, whereas cuticular hydrocarbons are necessary for inducing short-range mating behavior.     

面向城市设计的环境实景感知实证研究

随着人们对生活期望的提高,城市设计开始越来越注重空间环境如何提升城市生活的质量和健康。神经科学和计算机图形学等技术的发展让我们能够更好的描述和测量物理环境对人情绪、认知等心智健康的影响,也能够更好的控制模拟环境刺激。文章简要总结了近两年来课题组在环境感知测量及设计决策支持方面的研究进展,主要包括基于脑电和脑网络分析的环境认知能力影响、基于自主神经反馈的环境情感地图分析和情绪测量,以及基于激光扫描的虚拟环境构建等方面。     

Current status of kinematically complete studies of basic fragmentation processes in atomic systems

Recent developments on kinematically complete experiments on basic atomic fragmentation processes are reviewed. Comparisons between theoretical and experimental fully differential cross sections for single ionization of light atoms by charged particle impact are analyzed. Furthermore, a method developed very recently, four-particle Dalitz plots, is discussed in context of double ionization. The extraordinary power of these plots is their capability to provide a comprehensive picture of the momentum exchange between all four final-state particles in a single spectrum.     

Radikalabfang. III [1] ESR-spektroskopische Untersuchung von Radikalreaktionen eines bicyclischen 1-Hydroxy-3-imidazolin-3-oxids [2]

Spin Trapping. III. Studies of Radical Reactions of a Bicyclic 1-Hydroxy-3-imidazoline-3-oxide Radical addition reactions to the nitrono group and the oxidation of the 8-hydroxy-1,4,5,7-tetramethyl-6,8-diazabicyclo[3.2.1]oct-6-en-6-oxide 2b were investigated by e.s.r.-spectroscopy. Oxidation of 2b by Ag₂O, PbO₂, hydrogenperoxide, tert.-butoxy and benzoyloxy radicals, respectively, yields a bicyclic nitroxide with typical a(N)-value (1,9 mT). Testing a wide range of carbon-centered radicals we did not find, however, any spin adducts in contrast to the literature. Only H-atoms are found to add to the nitrone function of 2b giving a bicyclic nitroxide 4b (R′ = H) with a(N)-value of 1,4 mT, a(H_ax) = 2,4 mT. The relationship between a ring-chain tautomerism of 2 as previously described and the formation of radicals has been demonstrated by radical reactions of derivatives of ring opened isomers 5b .