用长气体靶研究22Na+α共振散射

在日本东京大学CRIB 次级束装置上,用长气体靶开展了22Na+ α共振散射的厚靶实验研究。针对长气体靶实验中的两体运动学重构问题,提出了一套包括构建空间复杂几何关系、计算能量损失以及反应运动学的逐事件分析方法;对22Na+α共振散射的实验数据进行了重构分析,得到了E_c.m. = 4.2 ~ 5.4 MeV 区间22Na( α,α ) 的激发函数,从实验的激发函数中观测到了复合核26Al 5 个较为明显的共振峰。鉴于26Al 共振态的衰变模式比较复杂,本工作发现的26Al新共振态的能级性质有待进一步的理论分析。The 22Na+α resonant scattering is studied via a conventional thick target inverse kinematic method with an extended gas target. A data analysis method is proposed for the two-body reaction kinematic reconstruction, in which the spatial geometry, the reaction kinematics and the energy losses are considered. The experimental data of 22Na+ αresonant scattering have been thus reconstructed, and the excitation function is obtained in the energy interval of Ec.m. =4.2~5.4 MeV. Five resonant states in 26Al are observed in the experimental excitation function. Since several decay modes coexist for the observed 26Al resonant states, multi-channel theoretical analysis is thus needed to reveal their structure and decay features.     

相变温度低且宽的含有胆甾烯基和反式-4-烷基环己基苯氧基的二介晶化合物

Unsymmetrical dimesogenic compounds with cholesteryl and 4-（trans-4-n-alkylcyclohexyl）phenoxy parts were synthesized by condensation of cholester-3-yl 6-bromohexanoate with appropriate 4-（trans-4-n-alkylcyclohexyl）- phenols. Structures and thermal phase behaviour of these dimesogenic compounds have been confirmed by IR, IH NMR, elemental analysis, DSC, polarity microscopy and XRD measurements. Their thermal phase behaviour was significantly different with that of other cholesterol-based dimesogens while they exhibited low and wide phase transition temperature.     

日本寿险业效率变动实证研究:1998-2008

日本是世界上保险业最发达的国家之一.但自20世纪90年代以来随着泡沫经济的破灭,宏观经济和金融环境的恶化,日本保险业尤其是寿险业进入了停滞与调整期.面对这一情况,日本政府层面和公司层面都推出各种措施,振兴踯躅前行中的日本寿险业.利用数据包络分析(DEA)方法对1998 2008年期间日本全部寿险公司的技术效率、纯技术效率和规模效率及其变动趋势进行了测度,对日本寿险市场的发展演变历程进行全面分析,希望对中国寿险业的发展提供经验借鉴.     

用压电材料进行损伤鉴别的理论与数值分析

对压电材料用于损伤监测的理论和数值分析做了一些研究。首先,设计了一种用压电材料进行损伤监测的模型。然后,对这个模型进行分析,找出简单有效的解答办法,将求解过程分解为断裂力学分析和压电分析两部分,并通过适当的假设,进行了详细的理论推导。通过正电有限元程序进行仿真计算,将数值计算结果与理论解进行比较以验证提出理论的正确性,并分析得到了裂纹参数与压电层表面电势变化之间的关系和普通弹性材料泊松比对波峰参数的影响。最后,用提出的方法验算了两个例题。从结果来看,理论结果和数值结果非常接近。