The optical nonreciprocal response based on a four-mode optomechanical system

We propose a scheme for realizing the optical nonreciprocal response based a four-mode optomechanical system,consisting of two charged mechanical modes and two linearly coupled optical modes. Two charged mechanical modes are coupled by Coulomb interaction, and two optical modes are coupled to one of mechanical modes by radiation pressure. We numerically evaluate the transmission probability of the probe field to obtain the optimum optical nonreciprocal response parameters. Also, we show that the optical nonreciprocal response is caused by the quantum interference between the optomechanical couplings and the linearly coupled interaction that breaks the time-reversal symmetry.     

高功率微波作用下限幅器尖峰泄漏特性

针对限幅器在高功率微波（HPM）作用下的尖峰泄漏问题,基于搭建的HPM注入实验平台和电路仿真开展了研究。研究结果表明：当注入功率超过6 dBm时,限幅器会出现尖峰泄漏现象,限幅器泄漏尖峰的上升沿与脉宽随着注入功率的增加而减小,而绝对尖峰泄漏功率随注入功率的增加呈增长趋势,平顶泄漏功率呈近似“线性增加-缓慢下降-小幅增长”趋势。并且,实验结果显示：HPM脉宽与重频对限幅器尖峰泄漏特性基本无影响,其泄漏特性变化规律与单次脉冲的基本一致;尖峰泄漏能量随注入功率的增加而降低。     

无绝缘高温超导双饼线圈的瞬态电热特性分析

无绝缘高温超导线圈具有良好的电热稳定性和机械紧凑性,但其充电过程中却有明显的磁场延迟现象。为详细了解无绝缘高温超导线圈励磁过程的瞬态特性,建立了无绝缘高温超导线圈的同轴圆环等效电路模型。通过绕制一个670匝的无绝缘高温超导双饼线圈,在液氮温度下进行不同充电速率的励磁实验,初步验证了等效电路模型的正确性。基于该模型,针对线圈励磁过程的充电和恒流阶段,仿真得到了线圈各匝的径向电流分布规律和电热损耗特性。     

THE BÄCKLUND TRANSFORMATION AND NONLINEAR SUPERPOSITION FORMULA OF SOLUTIONS FOR THE LIOUVILLE’S EQUATION IN HIGHER DIMENSIONS

In this paper, we show that Backlund transformation derived by Leibbrandt et al. for the Liouville’s equation in three spatial dimensions, ▽²a=expa, ▽²=-∂_x²+∂_y²+∂_z² can be decomposed into several Backlund transformations for the same equation in two spatial dimensions, moreover, the superposition formula which is derived from this transformation is actually invalid, thus the discussions based on that formula is incorrect as well. We also considered some results about the Liouville’s equation in N spatial dimensions.     

The mixed mode brittle fracture criteria in siliding mode fracture

It is well-known that the present mixed mode brittle fracture criteria are all theopening mode fracture criterion.We consider that mixed mode brittle fracture of slidingmode fracture exists too.Hence we propose three criteria of mixed mode brittle fracture ofsliding mode fracture;:the radial shearing stress criterion,the maximum shearing stresscriterion and the distortional strain-energy-density criterion.Thus,we can overall explainthe phenomena of brittle fracture in the structural elements with cracks.     

Synergism in electron gas in crossed fields

An electron gas in crossed electric and magnetic fields of arbitrary strength is considered in the framework of nonequilibrium statistical mechanics. It is known that more than one independent frequency existing in a system, which are of comparable magnitude, can generate coherent synergic radiation. In the present system three independent frequencies exist: viz the synchrotron frequency due to the magnetic field, the hopping frequency due to the electric field, and the plasma frequency. It is shown that all these can combine to generate a new synergic coherent radiation. The results also show the possibility of interpreting the quantum nature of Hall conductance as due to density function alone. Besides these, the solution admits the Schubnikov-de Haas oscillation of the electrical conductivity due to change in the fields.     

激光光源粒子计数器响应曲线对粒子折射率敏感度及多值性的分析

采用激光作光源的光学粒子计数器(L_OPC)克服了白炽灯作光源时使用寿命短、发光强度不稳定、需要经常标定的缺点,但激光波长的单一也带来了一些问题,如响应曲线对折射率敏感度的变化和多值性等问题。利用Mie散射理论,通过数值模拟实验,对L_OPC的这些问题进行了分析,提出了L_OPC实验样机的设计参数。     

基于LabVIEW空间瞬态光信号处理技术

分析了待探测的瞬态光信号、背景光信号和高频干扰信号频率的特性,利用LabVIEW软件平台设计虚拟仪器,进行信号处理和分析.设计了数字滤波器,对采集到的信号进行数字滤波,对滤波后的目标信号进行谱估计,得到功率谱密度.试验结果表明,该方法设计简单,运行可靠,滤波效果显著.     

阵列波导光栅波分复用/解复用器光谱响应效率的理论模型

基于单模光波导的本征模场分布,瑞利－索末菲衍射积分公式和天线原理的互易定理,给出耦合器中两个非接触平面光波导耦合特性的描述.基此,根据等光程差不等振幅多光束干涉的光场叠加原理,推导出新颖的阵列波导光栅波分复用/解复用器的光谱响应效率的解析函数表达式,这些表达式可为快速精确分析阵列波导光栅波分复用/解复用器的特性提供理论基础.同时,介绍了一个计算阵列波导光栅波分复用/解复用器特性的例子,给出其光谱响应度和信号通道串扰.     

Radiobiological response of human hepatoma and normal liver cells exposed to carbon ions generated by Heavy Ion Research Facility in Lanzhou

Human hepatoma and normal liver cells were irradiated with ¹²C⁶⁺ ion beams (LET = 96.05 keV/μm) and γ-rays at Heavy Ion Research Facility in Lanzhou (HIRFL). The chromatid breaks and break types were detected using the premature chromosome condensation technique. Our experimental results showed that chromatid breaks seem to have a good relation with ¹²C⁶⁺ absorbed dose and ¹²C⁶⁺ are more effective to induce chromatid breaks as compared to the γ-rays. For ¹²C⁶⁺ ion irradiation the major break was isochromatid break, while chromatid breaks were dominant for γ-ray irradiation. We also observed that the Relative Biology Effectiveness (RBE) of ¹²C⁶⁺ ion is about 2.5 times higher than that of γ-rays.