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Gust Front Statistical Characteristics and Automatic Identification Algorithm for CINRAD

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Journal of Meteorological Research 2014年第4期28卷 607-623页

作者：郑佳锋张杰朱克云刘黎平刘艳霞 key laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration Nanjing University of Information Science & Technology state key {2. of Severe Weather Chinese Academy of Meteorological Sciences College of Atmospheric Sciences Chengdu University of Information Technology Air Force Meteorological Center in Chengdu Fuzhou Meteorological Bureau

Gust front is a kind of meso-and micro-scale weather phenomenon that often causes serious ground wind and wind shear. This paper presents an automatic gust front identification algorithm. Totally 879 radar volume-scan samples selected from 2. gust front weather processes that occurred in China between 2.09 and 2.12.are examined and analyzed. Gust front echo statistical features in reflectivity, velocity, and spectrum width fields are obtained. Based on these features, an algorithm is designed to recognize gust fronts and generate output products and quantitative indices. Then, 315 samples are used to verify the algorithm and 3 typical cases are analyzed. Major conclusions include： 1） for narrow band echoes intensity is between 5 and 30 dBZ, widths are between 2.and 10 km, maximum heights are less than 4 km （89.33%are lower than 3 km）, and the lengths are between 50 and 2.0 km. The narrow-band echo is higher than its surrounding echo. 2. Gust fronts present a convergence line or a wind shear in the velocity field;the frontal wind speed gradually decreases when the distance increases radially outward. Spectral widths of gust fronts are large, with 87.09% exceeding 4 m s-1 . 3） Using 315 gust front volume-scan samples to test the algorithm reveals that the algorithm is highly stable and has successfully recognized 2.7 samples. The algorithm also works for small-scale or weak gust fronts. 4） Radar data quality has certain impact on the algorithm.

关键词： gust front statistical characteristics identification algorithm narrow-band echo

A Control Simulation Method of High-Speed Trains on Railway Network with Irregular Influence

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Communications in Theoretical Physics 2011年第9期56卷 411-418页

作者：杨立兴李想李克平 state key {2. of Rail Traffic Control and Safety Beijing Jiaotong University

Based on the discrete time method, an effective movement control model is designed for a group of high- speed trains on a rail network. The purpose of the model is to investigate the specific traffic characteristics of high-speed trains under the interruption of stochastic irregular events. In the model, the high-speed rail traffic system is supposed to be equipped with the moving-block signalling system to guarantee maximum traversing capacity of the railway. To keep the safety of trains＇ movements, some operational strategies are proposed to control the movements of trains in the model, including traction operation, braking operation, and entering-station operation. The numerical simulations show that the designed model can well describe the movements of high-speed trains on the rail network. The research results can provide the useful information not only for investigating the propagation features of relevant delays under the irregular disturbance but also for rerouting and reseheduling trains on the rail network.

关键词： high-speed train rail network discrete-time simulation irregular event

High Efficiency of Two Efficient QSDC with Authentication Is at the Cost of Their security

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Chinese Physics Letters 2009年第2期26卷 50-52页

作者：秦素娟温巧燕孟洛明朱甫臣 state key {2. of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing 100876 state key {2. of Integrated Services Network Xidian University Xi'an 710071 National laboratory for Modern Communications PO Box 810 Chengdu 610041

Two efficient protocols of quantum secure direct communication with authentication [Chin. Phys. Lett. 2. （2.08） 2.54] were recently proposed by Liu et al. to improve the efficiency of two protocols presented in [Phys. Rev. A 75 （2.07） 02.301] by four Pauli operations. We show that the high efficiency of the two protocols is at the expense of their security. The authenticator Trent can reach half the secret by a particular attack strategy in the first protocol. In the second protocol, not only Trent but also an eavesdropper outside can elicit half-information about the secret from the public declaration.

关键词： field emission molybdenum dioxide enhancement factor

High-throughput screening of room temperature active Peltier cooling materials in Heusler compounds

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npj Computational Materials 2022年第1期8卷 1899-1904页

作者： Huifang Luo Xin Li Yuxiang Wang Yeqing Jin Mingjia Yao Jiong Yang Materials Genome Institute Shanghai UniversityShanghai200444China state key {2. of Functional Materials for Informatics Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai200050China Zhejiang laboratory HangzhouZhejiang311100China

Active Peltier cooling enables Peltier heat transfer in addition to the traditional Fourier thermal conductance,which is useful in some special applications,such as the *** the material wise,however,the study on the active Peltier cooling materials is *** carried out a high-throughput workflow to screen out 5 room-temperature active Peltier cooling materials,GaSbLi_(2.,HgPbCa_(2.,SnTiRu_(2.,GeYbLi_(2.,and GeTiFe_(2.,from 2.58 Heusler *** the five materials are semimetals or very narrow band gap systems with high electrical *** of these materials have relatively large Seebeck coefficients due to the band *** effective thermal conductivityκ_(eff)s,which are the summation of active Peltier thermal conductivity and passive thermal conductivity,are all greater than Cu at the room temperature andΔT=1 *** present work gives a possible way to search active cooling Peltier materials for the applications of precise temperature control.

关键词： conductivity precise Seebeck

Effects of electron–optical phonon interactions on the polaron energy in a wurtzite ZnO/Mg_xZn_(1-x)O quantum well

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Chinese Physics B 2015年第9期24卷 448-453页

作者：赵凤岐张敏白金花 College of Physics and Electronic information Inner Mongolia Normal UniversityInner Mongolia Key Laboratory for Physics and Chemistry of Functional Materials

We investigated the properties of polarons in a wurtzite ZnO/MgxZn1-xO quantum well by adopting a modified Lee–Low–Pines variational method, giving the ground state energy, transition energy, and phonon contributions from various optical-phonon modes to the ground state energy as functions of the well width and Mg composition. In our calculations, we considered the effects of confined optical phonon modes, interface-optical phonon modes, and half-space phonon modes, as well as the anisotropy of the electron effective band mass, phonon frequency, and dielectric constant. Our numerical results indicate that the electron–optical phonon interactions importantly affect the polaronic energies in the ZnO/MgxZn1-xO quantum well. The electron–optical phonon interactions decrease the polaron energies. For quantum wells with narrower wells, the interface optical phonon and half-space phonon modes contribute more to the polaronic energies than the confined phonon modes. However, for wider quantum wells, the total contribution to the polaronic energy mainly comes from the confined modes. The contributions of the various phonon modes to the transition energy change differently with increasing well width. The contribution of the half-space phonons decreases slowly as the QW width increases, whereas the contributions of the confined and interface phonons reach a maximum at d ≈ 5.0 nm and then decrease slowly. However,the total contribution of phonon modes to the transition energy is negative and increases gradually with the QW width of *** the composition x increases, the total contribution of phonons to the ground state energies increases slowly, but the total contributions of phonons to the transition energies decrease gradually. We analyze the physical reasons for these behaviors in detail.

关键词： wurtzite quantum well electron–optical phonon interaction polaron energy

Single photon response of superconducting nanowire single photon detector

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Chinese Science Bulletin 2010年第4期55卷 441-445页

作者： YOU LiXing SHEN XiaoFang YANG XiaoYan state key {2. of Functional Materials for Informatics Shanghai Institute of Microsystem and Information Technology (SIMIT) Chinese Academy of Sciences Shanghai 200050 China

Single photon detection is one of the key technologies for quantum key distribution in quantum communication. As a novel single photon detection technology, superconducting nanowire single photon detector (SNSPD) surpasses conventional semiconducting single photon detectors with high count rate and low dark count rate. In this article, we introduce SNSPD fabricated from NbN ultrathin superconducting film and lab-based SNSPD system. The characteristics of single photon response pulse of SNSPD are analyzed in detail. Also discussed is the relationship between waveform of single photon response and system bandwidth. Circuit model is made to analyze the performance of SNSPD. The simulation result agrees well with the experimental data. Those results are valuable for understanding the mechanism of SNSPD and building future SNSPD system for quantum communication.

关键词：单光子探测器超导薄膜纳米线反应量子通信高计数率 PD系统密钥分配

Robust sparse principal component analysis

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Science China(information Sciences) 2014年第9期57卷 175-188页

作者： ZHAO Qian MENG DeYu XU ZongBen Institute for information and System Sciences School of Mathematics and StatisticsXi'an Jiaotong University Ministry of Education key Lab for Intelligent Networks and Network security Xi'an Jiaotong University

The model for improving the robustness of sparse principal component analysis(PCA)is proposed in this *** of the l2.norm variance utilized in the conventional sparse PCA model,the proposed model maximizes the l1-norm variance,which is less sensitive to noise and *** ensure sparsity,lp-norm(0 p 1)constraint,which is more general and effective than l1-norm,is considered.A simple yet efficient algorithm is developed against the proposed *** complexity of the algorithm approximately linearly increases with both of the size and the dimensionality of the given data,which is comparable to or better than the current sparse PCA *** proposed algorithm is also proved to converge to a reasonable local optimum of the *** efficiency and robustness of the algorithm is verified by a series of experiments on both synthetic and digit number image data.

关键词： noise outlier principal component analysis robustness sparsity

Particulate organic carbon export flux by ^(2.4)Th/^(2.8)U disequilibrium in the continental slope of the East China Sea

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Acta Oceanologica Sinica 2013年第10期32卷 67-73页

作者： BI Qianqian DU Jinzhou WU Ying ZHOU Jing ZHANG Jing state key {2. of Estuarine and Coastal Research East China Normal University

2.4Th is widely used to quantify the magnitude of upper ocean particulate organic carbon （POC） export in oceans. In the present work, the rates of particulate organic carbon export were measured based on the distribution patterns of 2.4Th/2.8U disequilibrium in the water column within the continental slope of the East China Sea （ECS） during May 2.11. The profiles of particulate and dissolved 2.4Th activities at all three stations showed a relative deficit with respect to 2.8U in the upper 100 m of the water column. The dissolved 2.4Th scavenging rates and the particulate 2.4Th removal rates and their residence times were calculated by a one-dimensional steady state model. The results showed that the dissolved a34Th scavenging rates and the particulate 2.4Th removal rates ranged from 12.4-61.4 dpm/（m3.d） and from 3.8-2..8 dpm/（m3.d）, respectively. The residence times of dissolved and particulate 2.4Th were in the range of 3.4-158 d and 63.7- 96.5 d, respectively. Combined with the measurement of POC/Z34Th ratios of suspended particles, POC export flux （calculated by carbon） from the euphotic zone was estimated in the study region, which ranged from 4.14-14.7 mmol/（m2..d）, with an average of 8.2. mmol/（m3.d）, occupying 35% of the prime productivity in the study area. The results of this study can provide new information for better understanding the carbon biogeochemical cycle within the continental slope of the ECS.

关键词： 2.4Th/2.8U disequilibrium residence time POC export East China Sea (ECS)

Effects of pulse energy ratios on plasma characteristics of dual-pulse fiber-optic laser-induced breakdown spectroscopy

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Chinese Physics B 2022年第2期31卷 387-397页

作者： Yu-Hua Hang Yan Qiu Ying Zhou Tao Liu Bin Zhu Kaixing Liao Ming-Xin Shi Fei Xue Suzhou Nuclear Power Research Institute Suzhou 215004China key laboratory for Physical Electronics and Devices of the Ministry of Education Faculty of Electronic and Information EngineeringXi’an Jiaotong UniversityXi’an 710049China state key {2. of Electrical Insulation and Power Equipment Xi’an Jiaotong UniversityXi’an 710049China

Laser-induced plasmas of dual-pulse fiber-optic laser-induced breakdown spectroscopy with different pulse energy ratios are studied by using the optical emission spectroscopy(OES)and fast *** energy of the two laser pulses is independently adjusted within 0–30 m J with the total energy fixed at 30 m *** inter-pulse delay remains 450 ns *** the energy share of the first pulse increases,a similar bimodal variation trend of line intensities is *** two peaks are obtained at the point where the first pulse is half or twice of the second one,and the maximum spectral enhancement is at the first *** bimodal variation trend is induced by the change in the dominated mechanism of dual-pulse excitation with the trough between the two peaks caused by the weak coupling between the two *** increasing the first pulse energy,there is a transition from the ablation enhancement dominance near the first peak to the plasma reheating dominance near the second *** calculations of plasma temperature and electron number density are consistent with the bimodal trend,which have the values of 1702..47 K,2.75×10^(17)cm;and 12.15.93 K,1.17×10^(17)cm;at a time delay of 550 *** addition,the difference between the two peaks decreases with time *** the increase in the first pulse energy share,the plasma morphology undergoes a transformation from hemispherical to shiny-dot and to oblate-cylinder structure during the second laser irradiation from the recorded images by using an intensified charge-coupled device(ICCD)***,the peak expansion distance of the plasma front first decreases significantly from 1.99 mm in the single-pulse case to 1.34 mm at 12.18(dominated by ablation enhancement)and then increases slightly with increasing the plasma reheating *** variations in plasma dynamics verify that the change of pulse energy ratios leads to a transformation in the dual-pulse excitation mechanism.

关键词： fiber-optic laser-induced breakdown spectroscopy(FO-LIBS) dual-pulse excitation pulse energy ratio spectral enhancement