基于北京流星雷达的MLT区域大气风场研究

探测和研究大气风场是认知中高层大气结构的最重要的手段之一,其中流星雷达是一种非常好的观测大气风场的手段。为了更好地了解中纬中间层-低热层(MLT)区域大气风场的特征,本文利用2016年北京流星雷达反演的风场数据进行研究。首先研究了大气平均风场随时间和高度的变化特征,得出1~3月北京上空MLT区域的纬向风均以西风为主,经向风南风与北风交替显著,但仍以北风为主导的结论。继而对于90 km处的大气潮汐波进行研究,通过Lomb-Scargle功率谱方法和谐波拟合得出了大气潮汐随时间的变动规律,即中纬地区大气水平风场受到的潮汐波影响以半日潮汐为主、周日潮汐次之。     

大气重力波引起的偶发钠层研究

利用了中国科学院临近空间环境野外综合探测站（廊坊,39N,116E）的钠荧光多普勒激光雷达和流星雷达的探测数据对廊坊上空大气重力波引起的偶发钠层（SSL）进行了研究。首先从大气重力波方程出发,计算分析了大气水平风剪切和垂直风场之间的相位关系;其次利用了钠荧光多普勒激光雷达和流星雷达的实测数据对大气重力波引起的偶发钠层进行了分析研究;经研究分析可知,由于大气重力波引起强的水平风切变和垂直风场风向反转的共同作用,其堆积效应使得钠原子密度增强,形成了偶发钠层。     

极区夏季中间层潮汐和平均风的短期变化特征

利用德国ＳＯＵＳＹ ＶＨＦ雷达在中间层高度上６天的观测数据,研究了夏季极区中间层大气潮汐和水平风的变化特征。动态谱分析表明,半日潮是极区夏季中间层高度上占支配地位的波动;周日潮通常较弱,偶尔也会增长到与半日潮相当的强度;１／８ｃｐｈ频率附近偶尔出现较强的谱峰,但持续时间更短。潮汐谱峰对应的频率一般与其定义值有偏离,说明它们经常处在被扰动的状态。在相差２．７ｋｍ的两个高度上纬向和经向平均风的时间变化     

中层顶准单色重力波特性的钠荧光多普勒激光雷达观测分析

利用2011~2013年期间60 h的钠荧光多普勒激光雷达温度和风场数据,采用矢端曲线法提取廊坊上空85~95 km中层顶区域准单色惯性重力波的所有参量,并统计准单色大气重力波的活动特性。获得的85次准单色重力波事件中,上传（下传）重力波64次（21次）,占总数的75。29%（24。71%）。垂直波长（水平波长）和观测周期平均值分别为6。6 km（727。8 km）和7。4 h,分别集中在6~9 km（200~800 km）和2~7 h,固有周期平均值为7。76 h,主要集中在3~9 h,水平传播方向分布比较均匀,没有占主导的传播方向。对于上传重力波,水平背景风在大气重力波水平传播方向上的分量取正值和取负值的概率大致相等,但对于下传重力波,该风场分量取正值的概率大约是取负值的2倍,说明观测到的下传大气重力波在中层顶区域多为顺风传播。     

背景风场和温度梯度对重力波传播的影响

运用射线跟踪方法，计算了背景风场和温度梯度共同影响下大气重力波的传播射线，结果表明，在顺风传播情况下，较小波长的重力波在１００ｋｍ左右的高度上被捕获，较大波长时可穿透传播到热层，但射线在水平方向拉伸；在逆风传播情况下，较长波长的波在１２０ｋｍ之下的高度发生无环反射，较短波长的波在２００ｋｍ以上的高度发生有环反射，而介于两种反射波的波长之间的波则穿透传播到热层高度，射线变陡。分析表明，上述波的反射、     

基于武汉MST雷达的对流层异常强反射回波观测

为研究中层-平流层-对流层(MST)雷达在对流层高度上的回波机制,利用特殊天气条件(切断低压)下的雷达回波功率、风场,采用Lomb-Scargle谱分析、谐波拟合、Richardson数等方法分析对流层上部出现回波功率异常的现象。结果表明,在切断低压的天气条件下,急流和深对流造成持续存在的重力波源,重力波由下至上传播至对流层顶下方并发生饱和破碎,能量耗散在大气中,破坏了大气的静力稳定,形成K-H不稳定层,进而发展为湍流,使对流层区域出现雷达回波功率增强。     

吉林一次暴雨激发平流层重力波的AIRS观测

为了分析中国陆地区域深对流激发平流层重力波的特征,针对2010年7月20日发生在吉林上空的一次暴雨事件,利用Aqua卫星高光谱大气红外探测器（Atmospheric Infrared Sounder, AIRS）的观测数据并结合ERA-interim高空背景场数据和S变换小波分析方法,分析了与暴雨相伴的深对流激发平流层重力波的传播特征,进一步讨论了重力波上传过程对暴雨发展的可能影响。     

散射辐射组合系统对造波水面的观测研究

介绍了新研制的Ｘ波段散射计组合系统。利用这一组系统进行了同时同地相继观测，得到ｖｗ，ｈｈ，ｈｖ多极化的后向散射系数σ＾０ＰＱ（ｐ，ｑ－ｖ，ｈ），ｖ和ｈ极化的辐射亮温度ＴＢＰ（ｐ＝ｖ，ｈ）。为模拟海面风场驱动起伏海面，利用室内人工造波池，在机械驱动下产生给定波谱的随机性或周期性起伏水面。用该散射计地组合系统观测多角度与多种起伏高度时的σ＾０ｐｑ－ＴＢｐ。并用双尺度随机粗糙面散射辐射理论模，烽值地模拟     

JONSWAP谱海面散射特性受相关参量的影响分析

联合北海波项目(JONSWAP)谱海面主要由风速、风区、谱峰因子等参数确定,针对模拟JONSWAP谱海面时相关参数的数值确定的需要,利用双叠加方法生成了满足JONSWAP谱分布的三维海面,分析了谱峰因子和方向集中度参数的取值对海面几何模型的影响;然后利用物理光学法仿真分析了JONSWAP谱海面的平均后向散射系数随谱峰因子以及方向集中度参数的变化关系。仿真结果表明,谱峰因子对海面平均后向散射系数影响小于1 dB,方向集中度参数对海面平均后向散射系数影响大于5 dB。因此得到了在研究JONSWAP谱海面的电磁散射时,谱峰因子可取为平均值以及方向集中度参数取值需要根据海浪的成长状态确定的结论。     

基于全天空流星雷达测量动量通量的新方法

全天空流星雷达是新一代的流星雷达, 可以接收流星余迹反射的无线电波, 目前主要应用于探测流星烧蚀区域的大气风场进而研究该区域的大气动力学.文中利用全天空流星雷达, 基于Hocking提出的测量重力波动量通量的新方法来研究昆明地区的大气环境参数—重力波的动量通量.由于采样时间间隔的不同, 该方法仍存在争议.本文主要利用昆明站工作频率为37.5 MHz的全天空流星雷达测得的流星数据来验证采样时间对重力波动量通量取值的影响, 同时利用工作频率分别为37.5 MHz、53.1 MHz的全天空流星雷达在2014年9月份观测的数据对该方法进行了对比分析, 结果表明:采样时间间隔的选取对重力波动量通量的取值有很大影响; 在合适的采样时间间隔内利用全天空流星雷达测量重力波的动量通量的新方法是可行的.     

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.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

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