带干扰的多险种风险模型的破产概率

将多险种风险模型推广到带干扰项的一种新模型,讨论了收益过程的性质,并利用鞅的方法得出了破产概率所满足的Lundberg不等式及其一般公式.     

银薄层控制金纳米四足体的重塑和等离激元调谐

探究了溶液中不同温度以及不同溶液成分(I^-的引入)对金纳米四足体(GNTPs)重塑过程的影响，表明了GNTPs的重塑机制为Ostwald熟化，即弱结合的表面Au原子在高凸曲率区域溶解和在凹区域重新沉积。这种重塑过程可以随时通过镀银薄层在几秒内阻止，GNTPs的形貌可以在最大程度上得到很好的稳定，从而也可以防止其光学性质的演变。在此基础上，通过紫外可见近红外(UV-Vis-NIR)吸收光谱和基于同步辐射的小角X射线散射(SAXS)进一步研究了GNTPs/Ag的稳定性，并通过表面增强拉曼散射(SERS)光谱证实了GNTPs/Ag的光学响应。     

Fabrication high-purity Fe nanochains with near theoretical limit value of saturation magnetization of bulk Fe

High-yield purity chain-like one-dimensional nanostructures consisting of single crystal Fe nanoparticles have been produced by using solution dispersion approach. Room temperature magnetic measurement shows that the as-fabricated Fe nanochains are ferromagnetic with a high saturation magnetization (203 emu/g) whereas the nanoparticles are single magnetic domains, which indicate that the as-synthesized products have superparamagnetism behavior with the saturation magnetization of about 28 emu/g. Maybe this results from the directional alignment of the nanoparticles. The excellent characteristic may have led to the potential applications in spin filtering, high density magnetic recording, and nanosensors.     

Measurements of the cross section for e(+)e(-) --> hadrons at center-of-mass energies from 2 to 5 GeV

We report values of R = sigma(e(+)e(-)-->hadrons)/sigma(e(+)e(-)-->mu(+)mu(-)) for 85 center-of-mass energies between 2 and 5 GeV measured with the upgraded Beijing Spectrometer at the Beijing Electron-Positron Collider.     

虚拟仪器技术及乐音的频谱分析

阐述了虚拟仪器技术的概念和特点,精确测量了３ 种乐音信号的波形、频谱和频率     

单胶子交换梯形近似下Bethe－Salpeter方程赝标解

将在动量空间具有积分形式的单胶子交换梯形近似下Ｂｅｔｈｅ－Ｓａｌｐｅｔｅｒ方程化为微分方程，求出该方程在四动量为零时的赝标解全部分量，其中第一分量为已知的Ｇｏｌｄｓｔｅｉｎ解．     

A note on regularity for a class of quasilinear elliptic equations

The following regularity of weak solutions of a class of elliptic equations of the form are investigated.     

Highly stable and efficient KTP-based intracavity optical parametric oscillator with a diode-pumped passively Q-switched laser

We present in this paper a highly stable and efficient KTP-based intracavity optical parametric oscillator with a diode-end-pumped Nd:YVO₄/Cr:YAG passively Q-switched laser. At the incident diode pump power of 4 W, the signal (1.57 μm) and idler (3.29 μm) average output powers up to 580 and 100 mW, respectively, have been achieved. The corresponding conversion efficiency from the input diode pump power to the output signal power is 14.5%, while that to the total OPO output (signal+idler) reaches 17%. To the best of our knowledge, these are the highest conversion efficiencies reported to date. After more than four hours of investigation, the OPO power stability better than 2% has been obtained. In addition, efficient cavity dumping of the IOPO has inevitably led to the short pulse duration (1.6 ns) and high peak power output (8.3 kW) at the signal wave. Additionally, the amplitude and repetition rate fluctuations of the signal pulses are well within 5%. PACS 42.55.Xi; 42.60.Gd; 42.60.Lh; 42.65.Yj     

变压器寄生参数和负载特性对高压脉冲波形的影响

构建了输出电压幅值为0～20 kV、脉冲重复频率为0.25～20 kHz的双极性高压脉冲电源实验平台,研究了变压器寄生参数与负载特性对输出脉冲波形的影响。采用等效电路复频域解析方法,分析了变压器寄生参数对输出脉冲波形的上升沿、平顶及下降沿的影响规律,并通过改变变压器绕线方案间接验证。发现变压器分布电容和漏感越大,输出脉冲波形上升沿与下降沿越平缓,过冲电压幅值越大,并采用脉冲变压器二次侧均匀密绕、一次侧均匀疏绕、高匝数的方案进行优化。进一步分析了纯阻性、阻容性或阻感性负载特性对输出高压脉冲波形的影响规律,发现电阻值增大（5～50 kΩ）,过冲电压幅值增大,脉冲上升沿和下降沿变陡;当负载电阻回路串联小电容时,过冲电压幅值显著增大,而电容值高于一定值时输出脉冲波形恢复至与纯电阻波形一样;当负载电阻回路串联电感时,输出脉冲波形下降沿变平缓。