电离层加热实验中反射高度下降特征的数值模拟

向电离层中注入大功率电磁波可引发地基非相干散射雷达观测的离子线和等离子体线回波功率增强现象.2010年秋季,在挪威开展了极区电离层离子线与等离子体线增强特征激发实验.实验中首次得到了VHF雷达观测的长生命周期的增强特征, 该现象系由参量衰变不稳定性引起的.另外,增强现象所处高度随加热的进行呈下降趋势,针对该特征文章给出了可能的物理机制,即该现象系由泵波促使反射高度附近的电子扩散效应增强引起的.文章利用修正的IRI和MSISE模型参数对加热实验中的反射高度阶跃性下降特征进行了仿真,仿真结果表明,加热电波引起的电子扩散效应可以使得反射高度下降,并且下降的高度与实验结果吻合较好,验证了该物理机制的可能性.     

利用含纯增长模式线的异常非相干散射谱反演扰动电子温度

基于平衡态非相干散射理论的GUISDAP程序包在拟合含有纯增长模式线的非相干散射功率谱及反演加热扰动电离层参量中存在严重误差,该文提出一种以未加热时刻的电离层参量为先验信息,利用最小二乘法搜寻最佳高斯峰描述纯增长模式线来修正实测非相干散射谱,并使用电子超高斯分布的非相干散射理论拟合修正后非相干散射谱来反演获取加热扰动电子温度的方法。通过将该方法用于分析2010年秋季我国在挪威开展的电离层加热实验数据表明：利用该方法对含纯增长模式线的实测谱修正拟合后获得的电子温度比未加热时刻提高约800 K左右,增幅比例约13%~50%,该结果与现有文献报道的电离层加热引起的电子温度增幅范围吻合较好。结论表明该方法适用于基于含纯增长模式线的非相干散射谱反演扰动电离层参量。     

不同加热条件下加热电离层的效应研究

利用电离层欧姆加热的理论模型和数值分析模型,根据数值模拟结果,对高频电波加热电离层的一级空间效应(主要是电子密度和电子温度的改变)进行定量分析,给出在不同地域(高纬区和中低纬区)、不同加热功率、不同加热频率(包括过密和欠密情况)和不同高度范围内,地基高频无线电波加热电离层引起的电离层主要参量的时空演化规律,以获取加热条件或参数的改变对不同区域电离层的加热效果.并结合国外相近纬度区、相近加热参数条件下的实验结果进行对比分析,给出了初步结论.     

空间磁化等离子体非线性受激电磁辐射进展

电磁波和磁化等离子体的非线性相互作用复杂,高功率电磁波调控电离层实验提供了研究非线性基本问题的主动方式.为构建空间磁化等离子体受激电磁辐射(stimulated electromagnetic emissions,SEEs)体系,本文首先总结了磁化等离子体中可能发生的参量不稳定性;其次,回顾了近十年国际电离层加热激发S...     

大功率高频无线电波加热电离层

利用大功率高频无线电波加热低电离层和高电离层的理论模型,选择不同的加热发射机参数,计算了电离层电子温度和电子密度的变化,模型计算结果与一些实验结果有着很好的一致性.在此基础上,具体讨论了不同的背景大气和背景电离层参数对加热效果的影响,最后简单地分析了对人工加热电离层的可能应用.     

高频地波雷达垂直向电离层电子浓度估计方法

高频地波雷达工作时, 往往同时接收到大量的电离层反射回波, 这些电离层杂波会对目标检测造成严重影响, 因此, 电离层杂波抑制是当前高频地波雷达领域的研究热点.文章将电离层回波视为可用信源, 从中反演出垂直方向电离层对应的电子浓度与等离子体频率.对R-D(Range-Doppler)谱图进行预处理, 获取垂直方向的电离层回波谱, 建立其回波功率与电离层雷达散射截面积之间的数学模型, 进而得到对应的电子浓度.在高频地波雷达站进行了实验, 并将反演结果与IRI-2012进行对比, 验证了该方法的可行性和有效性.     

高频地波雷达电离层杂波统计特性研究

高频地波雷达工作时, 往往同时接收到大量的电离层反射回波, 这些电离层杂波会对目标检测造成严重影响, 因此, 电离层杂波抑制是当前高频地波雷达领域的研究热点.文章将电离层回波视为可用信源, 从中反演出垂直方向电离层对应的电子浓度与等离子体频率.对R-D(Range-Doppler)谱图进行预处理, 获取垂直方向的电离层回波谱, 建立其回波功率与电离层雷达散射截面积之间的数学模型, 进而得到对应的电子浓度.在高频地波雷达站进行了实验, 并将反演结果与IRI-2012进行对比, 验证了该方法的可行性和有效性.     

背景电离层半球不对称特征研究

由于背景电离层关于磁赤道存在南北不对称,可能对赤道电离层中的等离子体不稳定性过程产生影响,背景电离层参数的变化可能作为不规则结构出现和闪烁发生的前兆.本文利用通量管积分方法,研究背景电离层电子密度和Pedersen电导率的半球不对称特征,发现积分电子密度N和积分Pedersen电导率〖AKΣ～9〗P以及F区积分电导率〖AKΣ～9〗FP与E区和F区积分电导率之和〖AKΣ～9〗E+FP的比值〖AKΣ～9〗FP/〖AKΣ～9〗E+FP的不对称强度随季节和太阳活动的变化规律与实验观测的不规则结构和闪烁活动的变化规律存在联系.这表明背景电离层电子密度和Pedersen电导率的分布对不规则结构和闪烁活动的出现有重要影响,表征积分电子密度和积分Pedersen电导率不对称强度的参数IN和IP可作为一种应用于电离层闪烁预报系统的预报指数.     

电离层背景状态对大功率短波加热电离层效应的影响

从电离层加热实验出发,模拟研究了低纬地区(Arecibo)和高纬地区(Troms?)加热效应.首先验证了该文计算的正确性,在此基础上研究了背景电离层电子密度梯度和泵波频率 HFf 与临界频率0F2f 比值对电离层加热效应的影响,结果表明:电子密度梯度越小,加热效果越强;过密加热时,加热效果随泵波频率与临界频率的比值增大而增强,但同时受电波反射高度影响,该比值较低时可能也会存在一个使加热效果增强的取值范围.最后分析了在不利的电离层背景状态下如何有效选择加热参数,以获得较为理想的加热效果.     

导航、电子对抗、制导

TN96 01041479奥斯特/GPS掩星与地面留达联合观测电离层电子密度的初步结果/张训械(中和阵完武汉物理与数学研究所波谱与原子分子物理国家重点实验室)弃全球定位系统一2000,25(3).一1一5文章给出了1 999年10月奥斯特ZGPS掩星与日本MU雷达和数字测高仪的联合观恻结果.奥斯特掩星反演得到的电子密度剖面与地面雷达观测的进行了比较,结果表明:天基和地基雷达观测的电子密度是一致的.文章还给出利用G PS的单频信号反演电离层电子密度剖面技术和3维射线追踪技术模拟掩星结果.图4参8(许)TN96〔)飞()414吕lj上海地区G PS/STORM试验与结果…     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks     

Call for Papers—Feature Topic,Vol.12,No.7,2015

正Information Centric Networking Information-Centric Networking(ICN) is an emerging direction in Future Internet architecture research,gaining significant tractions among academia and industry.Aiming to replace the conventional host-to-host communication model by a data-centric model,ICN treats data content as the first