纯弯梁加环孔边应力分析

本文用弹性理论平面问题的复变函数方法,分别对具有圆角的正三角形和正方形小孔且在孔边焊有绝对刚性环的纯弯矩形窄梁作了孔边应力计算和分析,发现当孔口置子某些方位时,加环孔边的主拉应力峰值反而比无环情况有明显的提高.这一情况的发生对脆性材料的构件是个不利因素,应予注意.     

低噪声通过特性的测量仿真研究

本文研究运用组合传感器和声压、振速联合信息处理技术进行低品声通过特性的测量。通过特性的背景噪声出非相干的各向同性白噪声和相干的交通干扰组成,交通干扰又分为平稳与非平稳两种,用平均声强器来抗非相干干扰;用交通干扰能量流中心方位抑制技术来抗平稳的相干干扰;对于非平稳的相干干扰而能量流中心方位抑制技术。仿真试验表明效果良好。     

向列相液晶中强非局域空间光孤子传输的理论研究

对向列相液晶中非局域空间孤子的传输进行了理论研究.基于非线性液晶孤子传输方程，采用Gauss形式的试探解，不仅得到了空间孤子的解析解,而且还在临界功率附近得到了呼吸子的解析解.通过数值模拟证明我们的结果比Conti和Assanto等人的结果更合理.同时，对液晶中的非局域孤子模型和Snyder等提出的强非局域孤子模型进行了全面的比较. 关键词： 向列相液晶 空间孤子 非局域非线性 呼吸子     

Coherent Scattering of Light by Bose-Einstein Condensation in a Tight Confinement

We have observed strong scattering of a probe light by dilute Bose-Einstein condensate （BEC） ^87Rb gas in a tight magnetic trap. The scattering light forms fringes at the image plane. It is found that we can infer the real size of the condensation and the number of the atoms by modelling the imaging system. We present a quantitative calculation of light scattering by the condensed atoms. The calculation shows that the experimental results agree well with the prediction of the generalized diffraction theory, and thus we can directly observe the phase transition of BEC in a tight trap.     

中国人口演化模型与中国未来人口预测研究

以中国57年人口数据为基础,建立中国人口演化规律的一阶变系数差分方程数学模型,求得方程解析解后对中国未来45年的人口变化趋势作了较为科学的预测,期望为人口政策的科学制定提供一定依据。     

Suprathreshold Stochastic Resonance in a Single Comparator

Stochastic resonance usually appears when stimulus is too weak to overcome barriers in a nonlinear system. Unusually, we demonstrate that in a simple competitor as a prototype model, stochastic resonance can still occur when the stimulus is predominantly suprathreshold. This result provides new knowledge for understanding of mechanism underlying information process in biological systems and aIso finds appfications in signal processing.     

Modified Woods-Saxon Potential for Heavy-Ion Fusion Reaction

A modified Woods-Saxon （MWS） potential is proposed for describing nucleus-nucleus interaction based on the Skyrme energy-density functional approach. Fusion barriers for a large number of fusion reactions from light to heavy systems can be described well with this potential. The suitable incident energies for fusion reactions leading to superheavy nuclei are also explored. It seems to us that the MWS potential is useful for selecting the suitable incident energies for fusion reactions for producing super-heavy nuclei.     

Ordered InAs Quantum Dots with Controllable Periods Grown on Stripe-Patterned GaAs Substrates

GaAs （001） substrates are patterned by electron beam lithography and wet chemical etching to control the nucleation of lnAs quantum dots （QDs）. InAs dots are grown on the stripe-patterned substrates by solid source molecular beam epitaxy. A thick buffer layer is deposited on the strip pattern before the deposition of InAs. To enhance the surface diffusion length of the In atoms, InAs is deposited with low growth rate and low As pressure. The AFM images show that distinct one-dimensionally ordered InAs QDs with homogeneous size distribution are created, and the QDs preferentiMly nucleate along the trench. With the increasing amount of deposited InAs and the spacing of the trenches, a number of QDs are formed beside the trenches. The distribution of additional QDs is long-range ordered, always along the trenchs rather than across the spacing regions.     

儿童鼻腔钮扣式电池异物并发鼻中隔穿孔的临床观察

目的防止并减少鼻腔钮扣式电池异物并发鼻中隔穿孔。方法25例病例全部在局或全麻下取出鼻腔钮扣式电池，取出后进行局部冲洗、换药等综合治疗。结果25例中20例经过综合治疗并发鼻中隔穿孔1例，5例未经过综合治疗前并发鼻中隔穿孔。结论鼻腔钮扣式电池异物取出后对局部进行冲洗、换药等综合治疗，可使腐蚀而糜烂的鼻粘膜得到有效的控制，并有效地防止鼻中隔穿孔。