Status of the standard solar model prediction of solar neutrino fluxes

The Standard Solar Model (BP04) predicts a total ⁸B neutrino flux that is 17.2% larger than that measured in the salt phase of the SNO detector (and if it is significant, it will indicate oscillation to sterile neutrinos). Hence, it is important to examine in detail the uncertainties (and values) of inputs to the BP04. Currently, the largest fractional uncertainty is due to the new evaluation of the surface composition of the Sun. We examine the nuclear input on the formation of solar ⁸B [S ₁₇(0)] and demonstrate that it is still quite uncertain due to the ill-known slope of the measured astrophysical cross section factor and thus illdefined extrapolation to zero energy. This yields an additional reasonable uncertainty due to extrapolation of _−3.0 ^+0.0 eV b ( _−14% ^+0% ). Since a large discrepancy exists between measured as well as predicted slopes, the value of S ₁₇(0) is dependent on the choice of data and theory used to extrapolate S ₁₇(0). This situation must be alleviated by new measurement(s). The “world average” is driven by the Seattle result owing to the very small quoted uncertainty, which we, however, demonstrate to be an overestimated accuracy. We propose more realistic error bars for the Seattle results based on the published Seattle data. The text was submitted by the author in English.     

DIRICHLET BOUNDARY VALUE PROBLEMS FOR SECOND-ORDER QUASI-LINEAR DIFFERENTIAL EQUATIONS WITH CHANGING SIGN NONLINEARITIES

This paper is concerned with the existence of positive solutions of two-point Dirichlet singular and nonsingular boundary problems for second-order quasi-linear differential equations with changing sign nonlinearities.     

1β—Methyl Carbapenem中间体的合成

综述了１β－Ｍｅｔｈｙｌ Ｃａｒｂａｐｅｎｅｍ中间体的合成方法，重点强调了如何构筑１位β构型的甲基。参考文献３７篇。     

High-yield solvothermal formation of magnetic CoPt alloy nanowires

One-dimensional (1D) magnetic nanomaterials have attracted much attention recently because of their applications in magnetic recording and spintronics. Nevertheless, it remains a challenge to prepare free-standing magnetic nanowires in high yield. This Communication reports the successful high-yield synthesis of an interesting 1D ferromagnetic CoPt alloy by direct decomposition of platinum acetylacetonate and cobalt carbonyl compound in ethylenediamine solvent through a solvothermal reaction. The CoPt alloy nanowires obtained have a tunable diameter of 10-50 nm and a length along the longitudinal axis of up to several microns, depending on crystallization temperature and reaction time. A unique formation mechanism involving coarsening and ripening under solvothermal conditions was discovered. This research opens new opportunities in synthesizing nanomaterials through low-temperature solvothermal processes.     

Vibrational energy relaxation dynamics of Si---H stretching modes on stepped H/Si(111) 1×1 surfaces

The vibrational energy relaxation rates of excited Si---H stretching modes on the monohydride steps of miscut H/Si(111) 1×1 surfaces are calculated using Bloch-Redfield theory combined with classical molecular dynamics (MD) simulation. The structure and vibrational frequencies of the surface are first investigated using the Car-Parrinello ab initio MD method. The calculated Si---Si---H bending frequencies and relaxed structures are then used to refine the empirical potential for the classical MD simulations. The lifetime of the excited Si---H stretching mode at the step is found to be shorter than the modes on the terrace. Both the magnitude and the trend of the calculated results agree well with the experimental measurement on the 9° monohydride stepped surface. The vibrational relaxation rate of the Si---H stretching modes on the 15° monohydride stepped surface are also calculated and predicted to have a slightly shorter lifetime than for the 9° surface.     

硫氰酸甲基三烷基季铵盐萃取Co（Ⅱ）的动力学

有关Co(Ⅱ)、Ni(Ⅱ)萃取分离的研究一直受到人们的重视。Preston报导了硫氰酸季铵盐(Q~ SCN-)萃取Co(Ⅱ)、Ni(Ⅱ)的平衡研究,认为Co(Ⅱ)的萃合物组成为Q_2Co(SCN)_4.本文用上升液滴法技术考察了Co(Ⅱ)/0.10mol·L~(-1)SO_4~(2-)/QSCN-煤油体系在298±1K条件下萃取速率R与CoSO_4、SO_4~(2-)和QSCN浓度的关系,确定了正向初始萃取速率方程,拟定了速控步骤。     

C_（60）化学修饰的PNVC材料的UV－VIS谱研究

本实验采用金属有机化学方法成功地将富勒烯分子引入到ＰＮＶＣ侧链形成ＣＢＰ（ＣｈａｒｍＢｒａｃｅｌｅｔＰｏｌｙｍｅｒ）型共聚功能材料，研究了其ＵＶ－ＶＩｓ谱行为。结果表明，Ｃ_（６０）或Ｃ_（６０）／Ｃ_（７０）混合物化学修饰的产物其紫外可见谱明显向长波方向移动，谱峰范围由２８０ｎｍ扩展至８７０ｎｍ。Ｃ_（６０）含量增加，红移程度增大，在可见区域的吸收程度亦增加。产物主要存在５个特征峰，分别位于２１５ｎｍ、２６５ｎｍ、２９８ｎｍ、３３５ｎｍ、３４５ｎｍ处，其中２１５ｎｍ峰为Ｃ_（６０）仅存的特征峰。最后讨论了不同合成条件与产物硝化处理对其ＵＶ－ＶＩＳ谱行为的影响。     

Centre line velocity variation in the laminar wake of a thin flat plate set parallel to a stream

Summary Wake study of a 0° incidence thin flat plate in a low-density supersonic flow has shown that the existing theories are not adequate to describe the near wake development in a low Reynolds number compressible flow. Comparison with the available experimental data is also made.

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Résumé Le sillage pour un écoulement supersonique de basse densité autour d'une plaque mince à incidence de 0° a été étudié. Il a été montré que les théories existantes ne sont pas suffisantes pour décrire le développement à proximité du sillage dans un écoulement compressible d'un nombre de Reynolds bas. On a aussi comparé le résultat de cette étude avec des résultats expérimentaux existants.

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Nomenclature x, y Axial and normal co-ordinates centred at the trailing edge (see Fig. 1) - U Free stream velocity - u Wake centre line velocity - u _s Slip velocity - M Free stream Mach number - L Length of the flat plate - Re _L Reynolds number based on the plate length and free stream conditions - T _w/T ₀ Wall to free stream stagnation temperature ratio