PM晶体声光混合型光学双稳态原理设计及频率反馈网络系统研究

本文简介PbMoO_3混合型光学双稳态的原理设计及其反馈网络系统的装置。通过实验及调节,测试了该器件的衍射曲线,反馈曲线以及光学双稳滞后回线。实践证明:PbMoO_3声光晶体具有良好的光学双稳特性,可以作为多通道开关,适用于波导技术。     

Recent progress and new challenges in isospin physics with heavy-ion reactions

The ultimate goal of studying isospin physics via heavy-ion reactions with neutron-rich, stable and/or radioactive nuclei is to explore the isospin dependence of in-medium nuclear effective interactions and the equation of state of neutron-rich nuclear matter, particularly the isospin-dependent term in the equation of state, i.e., the density dependence of the symmetry energy. Because of its great importance for understanding many phenomena in both nuclear physics and astrophysics, the study of the density dependence of the nuclear symmetry energy has been the main focus of the intermediate-energy heavy-ion physics community during the last decade, and significant progress has been achieved both experimentally and theoretically. In particular, a number of phenomena or observables have been identified as sensitive probes to the density dependence of nuclear symmetry energy. Experimental studies have confirmed some of these interesting isospin-dependent effects and allowed us to constrain relatively stringently the symmetry energy at sub-saturation densities. The impact of this constrained density dependence of the symmetry energy on the properties of neutron stars have also been studied, and they were found to be very useful for the astrophysical community. With new opportunities provided by the various radioactive beam facilities being constructed around the world, the study of isospin physics is expected to remain one of the forefront research areas in nuclear physics. In this report, we review the major progress achieved during the last decade in isospin physics with heavy ion reactions and discuss future challenges to the most important issues in this field.     

Heteroannihilation of the excited states of associates and monomers of fluorescein dyes on the silica surface at low temperatures

The processes of homo-and hetero-triplet—triplet annihilation (TTA) of Bengali rose on the spongy silicon surface have been investigated. It has been found that upon pulse photoexcitation on the silica surface photophysical processes involving the triplet states of monomers and their associates can develop. It has been shown that the processes of hetero-TTA are inhibited due to the decomposition of associates under the influence of hexane molecules in the molecular clusters of the dye adsorbates. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 6, pp. 734–737, November–December, 2005.     

K9光学玻璃化学钢化技术研究

为提高K9光学玻璃在一些特殊应用领域(如高压、温度变化剧烈等)的力学性能,并保证其光学性能符合精密光学仪器要求,对K9光学玻璃进行了化学钢化技术研究.以脆性材料断裂过程微裂纹扩展理论为基础,导出化学钢化玻璃强度应力因子计算模型,分析化学钢化表面应力与表面微裂纹深度、韧性之间的关系,指出化学钢化工艺应注意的事项.通过实验...     

近置多裂纹相互作用的渐近分析方法

考虑到近置裂纹的强相互作用,提出了一种多裂纹相互作用的渐近分析方法. 经典Kachanov 方法将裂纹表面伪面力分解为两部分：均匀分布部分和非均匀部分,并假设裂纹的相互作用 仅由均匀部分引起,而忽略非均匀部分的影响. 该假设大大简化了分析过程,而且当裂纹间 距不是很小时,有很好的精度. 但当裂纹非常靠近或者沿主荷载方向重叠时,由于裂纹尖端 进入了其它裂纹的应力强化区或者应力屏蔽区,强相互作用使得该假设不再合理,从而带来 较大的误差. 为了提高分析近置多裂纹问题的精度,将裂纹表面伪面力分解为抛物线型分布 部分及高阶部分,考虑抛物线型分布张力对其他裂纹的影响,同样忽略高阶部分的影响. 通 过对三共线裂纹及两平行偏置裂纹两个实例的分析,验证了对于近置裂纹,新渐近方法具有 良好的精度.     

动脉中非平稳流动壁面剪切力及其Hilbert-Huang变换

本文通过数值方法求解均匀动脉中的非平稳脉动流,给出了通过测量非平稳脉动血流量确定壁面切应力的方法.作为算例,采用实测的大鼠颈总动脉流量信号,求出了均匀动脉壁面切应力波形.进一步对求得的切应力波形进行经验模态分解(EMD),得到了切应力波形的各内在模态(IMF),以及Hilbert幅值谱.从切应力波形经Hilbert-Huang变换得到的IMF和Hilbert谱图可以明显地看出切应力各频率成分的物理意义.所得结果为进一步深入研究非平稳脉动切应力与血管重建的关系提供了一种方法学基础.     

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通过对拱顶储罐罐壁承受轴向载荷、初始几何缺陷及轴压失稳状况研究,指 出在固定顶罐设计、建造和运行各阶段都应进行罐壁轴压稳定性校核. 根据圆柱薄壳稳定性 理论和轴压失稳临界应力数值分析计算结果,提出固定顶罐罐壁轴压稳定性校核方法和数学 模型,并运用回归分析方法建立罐壁轴压失稳临界应力计算公式. 对几种常用规格的拱顶罐 有初始挠度缺陷罐壁轴压稳定性分析表明：随储罐容积和罐壁初始挠度增大,罐壁轴压稳定 性呈减弱趋势.     

126Cs的高自旋态能级结构

利用融合蒸发反应¹¹⁶Cd(¹⁴N,4n)¹²⁶Cs布居了¹²⁶Cs的高自旋态.观测到了100多条新的γ跃迁和相应的能级,建立了双奇核¹²⁶Cs由9个转动带构成的能级纲图.尝试性地指定了大部分能级的自旋和宇称以及各转动带的Nilsson单粒子组态.极大地丰富了已有的实验结果.