Photochemistry of bicyclic δ-thia-α,β-unsaturated ketones a vinylketene mechanism

Photolyses and pyrolyses of bicyclic δ-thia-α,β-unsaturated ketones (8) and (la) were investigated. Experimental and spectroscopic evidences support a vinylketene mechanism both for photolysis and pyrolysis.     

Electron microscopy of submicron particles in natural waters—Morphology and elemental analysis of particles in fresh waters

Submicron particles larger than about 0.1m in pond and river waters were collected on a carbon film mounted on a specimen grid by centrifugation and then studied morphologically and analyzed for major elements heavier than sodium, with a high-resolution transmission electron microscope equipped with an energy dispersive X-ray analyzer. If available, the data were compared with those of particles artificially prepared under various conditions. Four typical particles—aluminosilicate, quartz, fine-particle aggregates containing silica and iron(III) oxide, and microorganisms—were found in fresh waters.     

Emergent radiation from an inhomogeneous,plane-parallel planetary atmosphere calculated by using the “adding” method

The method of computation of diffuse reflection radiation from an inhomogeneous, plane-parallel planetary atmosphere is discussed by using the “adding” method. If the atmosphere is simulated by a number of homogeneous sublayers, the diffusely reflected radiation from the atmosphere can be expressed in terms of the reflection and the transmission matrices of radiation of sublayers. This method can be easily extended to the problem including aerosol distribution with height variation. Polarization is also included.     

Specular reflectivity studies of the electrosorption of aromatic hydrocarbons on gold electrode in 2-methoxyethanol solution

Electrosorption of some aromatic hydrocarbons on gold electrode has been studied by the measurement of the specular reflectivity change in 2-methoxyethanol containing about 0.2 M NaClO₄. In the presence of the hydrocarbons, the reflectivity decrease was found to be enhanced in the positive side of the potential region, the decrease being ascribed to the taking place of adsorption. With the assumption that the reflectivity decrease is proportional to the coverage, the observed change was analysed by varying the concentrations of the hydrocarbon at varied potentials. The observed values could fairly be elucidated on the basis of the modified Langmuir isotherm in which the potential dependent term is included and the adsorption is assumed to proceed through the replacement of an adsorbed solvent molecule. Regarding a larger molecule, a larger number of solvent molecules was replaced and a larger negative value of the energy of adsorption was obtained. This is in accordance with the mechanism that the hydrocarbons are adsorbed by lying flat on the surface through the π-electron interaction. The rate of adsorption was examined at a lower concentration range and could be elucidated in terms of the diffusion controlled mechanism. Extension of the McIntyre-Aspnes theory to the multilayer system has been attempted and the net reflectivity change was shown to be the sum of the change due to each layer. The major cause of the reflectivity change was examined by comparing the observed wavelength dependence of the change with those calculated on the basis of the increase in the refractive index in the double layer or the electroreflectance. Both of the calculated curves were not in accordance with the observed curve, indicating that the other mechanism might play an important role.     

超细纹理超塑性材料Zn-Al合金及其在无铅和地震减振装置方面的应用(英文)

pacc:7850C SincetheGreatHanshinEarthquakein 1995,manyinvestigationsontheseismicdamper havebeenmade.Ontheotherhand,italsotheo reticallyprojectedthatultrafinegrainedZn-Al alloyscouldshowsuperplasticityatlowtempera tures[1-4].Authorstriedtomakeamassiveultr…     

145Tb的高自旋态能级纲图

利用能量为161—175MeV的³²S束流,通过反应¹¹⁸Sn(³²S,1p4n)产生了¹⁴⁵Tb的高自旋态.进行了γ射线的激发函数、γγt符合测量.首先建议了由24条能级和42条γ跃迁组成的¹⁴⁵Tb核的能级纲图,并指定了各条能级的自旋值及部分低位能级的宇称.用一个πh_11/2价质子与¹⁴⁴Gd核芯激发态的耦合定性地解释了¹⁴⁵Tb的一些低位激发态.