关于P方凸函数的一个Hadamard型不等式

在凸函数Hadamard型不等式基础上,通过应用P方凸函数的一个充要条件,得到了P方凸函数的一个Hadamard型不等式.     

鼻渊丸质量标准的研究

目的：对鼻渊丸进行质量标准研究.方法：采用薄层色谱法对鼻渊丸进行定性鉴别;采用高效液相色谱法对木兰脂素进行含量测定.结果：该方法的线性范围为0.060 4～1.510 0μg;平均回收率为98.90%（RSD=1.97%,n=6）结论：方法可行,重复性好,能有效控制鼻渊丸的质量.     

基于潜在类分析的城市异质出行群体识别研究

异质出行群体的合理划分是提升出行需求预测准确性和实施主动式交通管理的关键,针对目前城市多方式出行群体划分研究的不足,在分析出行习惯与偏好差异影响因素的基础上,提出基于潜在类分析(Latent Class Cluster Analysis,LCCA)的城市异质出行群体识别方法.以北京市为例,应用揭示性偏好调查进行基础数据收集,运用Mplus软件编程实现LCCA模型估计.模型将出行者划分为三类异质出行群体,群体1:低出行+方式均衡组(20.4％),群体2:中高出行+小汽车偏好组(30.3％),群体3:高出行+绿色交通组(49.3％).模型回归结果表明:群体2、3的百分比与北京市小汽车、公共交通出行比例之差均不超过2％,证明提出的出行群体识别方法有效,个人属性、出行者对各交通方式的认知与态度对群体隶属影响显著.针对各异质出行群体提出了相应的绿色交通发展措施,为城市交管部门的精细化出行管控提供重要依据.     

GPS/Galileo组合区域增强PPP算法与评估

为了提高区域增强精密单点定位(PPP)系统参考站端非差模糊度的固定效率,设计了一种改进的GPS/Galileo组合区域增强PPP参考站和用户端的核心算法,提出了以消除接收机相关误差的固定单差模糊度作为约束,辅助非差模糊度固定的方法.研究了算法中基准与偏差项在参考站与用户间和不同参数间传递的过程,明确了大气延迟改正数中包含混合基准的具体成分.利用美国CORS站网的观测数据进行区域增强PPP模糊度固定解算实验,评估了GPS/Galileo组合系统可提供的解算效果及其相对于GPS单系统的增益.结果表明:相较于GPS单系统,当使用组合系统时用户PPP模糊度成功固定率提高4.5％,达到96.1％,可以在全天绝大多数时间提供正常服务,同时正确固定率提高2.9％;模糊度固定所需的时间节省了约13％.     

Quantum computation on gate-defined semiconductor quantum dots

During the past few years, researchers have made significant progress on quantum information processing in gate controlled semiconductor quantum dots. We review the global research efforts, including works by our group, which provides pathways towards applications in quantum computation.     

Interface stability in a capillary loop undergoing phase changes in non-gravitational conditions

A mathematical model based on the Lucas-Washburn equation has been developed to address the relationships between capillary height, capillary radius and heat flux in a capillary loop. The stability criteria at the interface are studied in detail by introducing a small perturbation to the interfaces of the capillary loop. The formulae deduced as a consequence are used to analyze the influence of height of the capillary wick and the stability in a capillary loop undergoing phase changes.     

Numerical study of three phase shifts and dual corrugation pitch modulated (CPM) DFB semiconductor lasers based on reconstruction equivalent chirp technology

A distributed feedback (DFB) semiconductor laser with three phase shifts based on reconstruction equivalent chirp (REC) tech-nology is proposed and investigated numerically. With the combination of multiple phase shifts and corrugation pitch modulated (CPM) structure, we also propose a novel and more complex structure named dual CPM, which has a flatter light power distribution along the laser cavity compared with the true double phase shifts DFB laser diode (LD), while the P-I curves are nearly the same. The proposed dual CPM structure is also designed and analyzed based on REC technology. The simulation results show that, the DFB semiconductor laser with complex structure such as phase shifts, or even arbitrary variation of the grating period can be achieved equivalently and easily by changing the sampling structure. But its external characteristics are almost the same as those DFB lasers with true phase shifts, or true arbitrary variation of the grating period. The key advantage of the REC technology is that it varies only the sampling structure and keeps the seed grating (actual grating in sampling structure) period constant. So its fabrication needs only low-cost and standard holographic exposure technology. Therefore we believe this method can achieve the high-end and low-cost DFB LD for mass production.     

基于粒子滤波的移动机器人SLAM算法

针对FastSLAM算法对传感器精度要求较高,不适用于方向性差的超声传感器问题,提出了一种基于超声概率栅格地图环境特征点提取匹配的移动机器人粒子滤波同时定位与地图创建(SLAM)算法.该算法可分解为机器人位姿估计和环境路标估计2个部分.基于蒙特卡罗定位原理利用粒子滤波算法对机器人运动轨迹进行估计;在建立全局超声概率栅格地图的基础上,利用概率栅格地图环境特征提取算法对环境路标坐标进行估计.实验证明,该算法较好地解决了超声测距传感器由于散射角大带来的特征点估计不准的问题,对环境路标和机器人轨迹的估计都比较准确.并对移动机器人累计误差进行了有效的补偿,减少了由于累积误差造成的移动机器人轨迹扭曲失真.     

First imaging observation of the gravity waves in the mesopause region in China

The first imaging observation experiment of the atmospheric gravity waves in the mesopause region with the all-sky OH Meinel band airglow CCD imager is made during 02:00 to 06:00 on January 5,2009,at Hancun (39.4°N,116.6°E),Langfang,Hebei in China.Quasi-monochromatic gravity waves (QMGWs) are found clearly in the observation data.Case studies show that their horizontal wavelengths,horizontal phase velocities,azimuth angles of horizontal propagation directions and periods of three QMGW examples are about 12....     

Rapid recovery of polycrystalline silicon from kerf loss slurry using double-layer organic solvent sedimentation method

The rapid development of photovoltaic (PV) industries has led to a shortage of silicon feedstock. However, more than 40% silicon goes into slurry wastes due to the kerf loss in the wafer slicing process. To effectively recycle polycrystalline silicon from the kerf loss slurry, an innovative double-layer organic solvent sedimentation process was presented in the paper. The sedimentation velocities of Si and SiC particles in some organic solvents were investigated. Considering the polarity, viscosity, and density of solvents, the chloroepoxy propane and carbon tetrachloride were selected to separate Si and SiC particles. It is found that Si and SiC particles in the slurry waste can be successfully separated by the double-layer organic solvent sedimentation method, which can greatly reduce the sedimentation time and improve the purity of obtained Si-rich and SiC-rich powders. The obtained Si-rich powders consist of 95.04% Si, and the cast Si ingot has 99.06% Si.