bluuebunny/crossref_metadata_2025 huggingface dataset:
First principles study of the effect of high V doping on the optical band gap and absorption spectrum of ZnO
Authors: Guo Shao-Qiang  , Hou Qing-Yu  , Zhao Chun-Wang  , Mao Fei  ,   College of Science, Inner Mongolia University of Technology, Hohhot 010051, China
Published: December 2020

Nowadays, the studies on optical band gap and absorption spectrum of V doped ZnO have presented two distinctly different experimental results, that is, the blue shift increases and decreases when the mole fraction of impurity increases in a range from 0.0417 to 0.0625. To solve this contradiction, according to the first-principles plane-wave ultrasoft pseudopotential of the density functional theory, we set up models for a pure ZnO cell and two supercells of Zn1-xVxO (x=0.0417, 0.0625) to calculate the total density of state, partial density of state, magnetism and absorption spectrum through using the method of GGA+U. The calculation results indicate that with the doping amount increasing from 2.083 at% to 3.125 at%, the magnetic moment of doping system increases and magnetism augments, too. Moreover, the volume of doping system increases, the total energy decreases and the formation energy becomes lower, thereby making the system more stable. Meanwhile, its optical band gap becomes wider, and the absorption spectrum shifts toward low energy. The calculation results are consistent with the experimental data.
First principles study of fluorinated boron-carbon sheets
Authors: Xu Lei  , Dai Zhen-Hong  , Wang Sen  , Liu Bing  , Sun Yu-Ming  , Wang Wei-Tian  ,   Institute of Opto-electronic Information Science and Technology, Yantai University, Yantai 264005, China
Published: December 2020

Based on the first principles, we investigate the structures and electronic properties of fluorinated BC3, BC5, and BC7. Through the fluorination of BC structure, boron-carbon sheets are more stable than the hydrogenation. The results show that the system becomes semiconductor only on condition that the boron atoms can be bonded with the carbon atoms, whereas, the whole system will become the conductor when all atoms participate in the bonding. With the variation of fluorination degrees, semiconductor-metal transitions appear in the BC3 compounds and metal-semiconductor-metal transitions appear in the BC5 and BC7 sheet. Theoretical analyses find that pz orbital of boron atoms plays an important role in the electronic transition. Because of the rich electronic properties, this kind of fluorinated boron-carbon compound will become potential nanoelectronic materials and our results can play a role in guiding experiments.
Electronic structures, band-gap origins and magnetisms of Ti2Cr-based alloys with CuHg2Ti-type structure
Authors: Jia Hong-Ying  , Dai Xue-Fang  , Wang Li-Ying  , Liu Ran  , Wang Xiao-Tian  , Li Peng-Peng  , Cui Yu-Ting  , Wang Wen-Hong  , Wu Guang-Heng  , Liu Guo-Dong  ,   School of Material Sciences and Engineering, Hebei University of Technology, Tianjin 300130, China;,   College of Physics and Information Technology, Chongqing Normal University, Chongqing 400044, China;,   Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
Published: December 2020

The electronic structures, band-gap origins and magnetisms of Ti2Cr-based alloys with CuHg2Ti-type structure are studied using the first principles calculations. It is found that Ti2CrK (K=Si, Ge) alloys are semiconductors Ti2CrK (K=Sb, Bi) alloys are predicted to be half-metallic ferrimagnets and their half-metallic band gaps are affected directly by the S states of Sb and Bi atoms. Ti2CrSn alloy is a completely-compensated ferrimagnetic semiconductor. Due to the different band-gap origins of Ti2CrSn alloy in two spin directions, we can adjust the width of band gap by doping engineering. The ferrimagnetic spin-gapless materials are achieved by substituting Si or Ge for Sn. Substituting Fe or Mn for Cr, we gain a series of half-metallic materials. Ti2Cr1-xFexSn and Ti2Cr1-xMnxSn alloys are in ferrimagnetic states. All the half-metallic Ti2Cr-based alloys follow Mtotal=Zt-18 rule (Mtotal is the total magnetic moment and Zt is the valence concentration).
Abnormal variation of optical properties of vanadium oxide thin film at semiconductor-metal transition
Authors: Yang Wei  , Liang Ji-Ran  , Liu Jian  , Ji Yang  ,   State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China;,   School of Electronic and Information Engineering, Tianjin University, Tianjin 300072, China
Published: December 2020

The optical properties of vanadium oxide thin film are measured at semiconductor-metal transition, including reflectance and transmittance results at different wavelengths which show different trends during the phase transition. With a multi-level reflection-transmission model of incoherent light, we calculate the values of refractive index n and extinction coefficient k at different wavelengths, and show that the abnormal optical properties result not only from the dependences of n and k on the wavelength, but also from multiple reflections in the absorbing film.
Size and ternary mixed crystal effects on interband absorption in wurtzite ZnO/MgxZn1-xO quantum wells
Authors: Gu Zhuo  , Ban Shi-Liang  ,   School of Physical Science and Technology, Inner Mongolia University, Hohhot 010021, China
Published: December 2020

Adopting a numerical method of solving self-consistently the Schrödinger equation and Poisson equation, the eigenstates and eigenenergies of electrons (holes) in a two-dimensional electron-hole gas are obtained for wurtzite asymmetric ZnO/MgxZn1-xO single quantum wells (QWs). In our computation, a realistic heterostructure potential is used, in which the influences from energy band bending, material doping and the built-in electric field induced by spontaneous and piezoelectric polarizations are taken into account. Furthermore, based on the Fermi's golden rule, the optical absorptions of electronic interband transitions in QWs, and their size and ternary mixed crystal effects are discussed. The results indicate that the increase of the Mg component in MgxZn1-xO enhances the build-in electric field, which forces electrons (holes) to approach to the left (right) barrier. This causes the interband transition absorption peak to decrease exponentially and to be blue-shifted. For different widths of QWs, the calculated results show that absorption peak decreases and transition energy shows a red shift with the increase of well width. The above conclusions are expected to give a theoretical guidance for improving the opto-electronic properties of materials and devices made of heterostructures with suitable optical absorption spectra and wave lengths.
A low on-resistance silicon on insulator lateral double diffused metal oxide semiconductor device with a vertical drain field plate
Authors: Shi Yan-Mei  , Liu Ji-Zhi  , Yao Su-Ying  , Ding Yan-Hong  ,   School of Electronics Information Engineering, Tianjin University, Tianjin 300072, China;,   School of Electronics Information Engineering, Tianjin University of Technology, Tianjin 300384, China;,   School of Microelectronics and Solid-State Electronics, University of Electronic Science and Technology of China, Chengdu 610054, China
Published: December 2020

To reduce the on-resistance and enhance the breakdown voltage of silicon on insulator (SOI) lateral double diffused metal oxide semiconductor (LDMOS) device at the same time, a low on-resistance SOI-LDMOS device with a vertical drain field plate and trench gate and trench drain (VFP-TGTD-SOI-LDMOS) is proposed. The device has the features as follows: first, a trench gate and a trench drain are adopted, which can widen the vertical current conduction area, shorten the lateral current conduction path, and lower the on-resistance. Secondly, a vertical field plate is used, which modulates the electric field around it, reduces the high electric field at the end of the drain electrode, and increases the breakdown voltage. The VFP-TGTD-SOI device is compared with a conventional SOI device, a trench gate SOI device, a trench gate and trench drain SOI device with the same dimensional device parameters using the two-dimensional semiconductor simulator MEDICI. The results show that under the condition of their own highest figure of merit (FOM), the specific on-resistance value of the VFP-TGTD-SOI device is reduced by 53%, 23%, and increased by 87%, respectively and the breakdown voltage is increased by 4% and reduced by 9% and increased by 45%, respectively. By comparing the FOMs of the four structures, it can be seen that the VFP-TGTD-SOI device has the highest FOM, which indicates that among the four structures, it maintains the lower on-resistance and holds the higher breakdown voltage at the same time.
Ag nanoparticles enhanced 2 um luminescences of Ho3+/Tm3+ codoped bismuth germanate glasses
Authors: Xue Bing  , Xu Yin-Sheng  , Li Yan-Yuan  , Qi Jia-Ni  , Lu Shan-Shan  , Lu Ke-Lun  , Chen Li-Yan  , Zhang Shao-Qian  , Dai Shi-Xun  ,   Advanced Technology Research Institute, Ningbo University, Ningbo 315211, China;,   School of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211, China;,   College of Science and Technology, Ningbo University, Ningbo 315211, China;,   Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
Published: December 2020

The Ho3+/Tm3+ codoped bismuth germanate glasses containing Ag nanoparticles (NPs) are synthesized by a chemical reduction method based on the conventional melting-quenching technique. The effect of concentration of Ag NPs on the 2 um emission is studied. The absorption band related to the surface plasmon resonance (SPR) of the Ag NPs is located in a range from 500 to 900 nm. Transmission electron microscopic image clearly reveals homogeneously dispersed Ag NPs with the sizes ranging from 5 to 10 nm. The luminescence spectra in a range of 1.7-2.3 um are collected. With the addition mass fraction of the AgCl up to 0.3%, the intensity of emission band of Ho3+ ions, centered at 2.03 um, is increased by 10 folds. The enhancement of 2 um luminescence is attributed to the enhanced local field induced by SPR of Ag NPs. The calculated absorption cross section and emission cross section are 0.491 10-20 cm-2 and 1.0310-20 cm-2, respectively. When the gain coefficient p=0.2, the positive gain would be realised.
Thermal-chemical coupling model of laser induced ablation on polyoxymethylene
Authors: Li Gan  , Cheng Mou-Sen  , Li Xiao-Kang  ,   College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410073, China
Published: December 2020

Polyoxymethylene (POM) is a good absorber of CO2 laser, so it is important to study the ablation mechanisms of polymer materials. Because the laser impact phenomena are terribly complex, there is no general understanding of the mechanism of laser induced ablation of POM. An explicit thermal-chemical coupling model is presented in this paper, which takes account of laser heating, phase transition, thermal degradation, and plume emission. Random thermal degradation is adopted to describe the chemical reaction process when POM is heated up, and consequently, the components of the degradation products under different degradation rates are acquired. The group contribution method is used to evaluate the thermodynamic properties of the degradation products, and the normal boiling point and critical temperature of the product mixture are obtained by the mixing law. If the product temperature is lower than the critical temperature, POM is ablated in the manner of liquid evaporation; otherwise the ablation mechanism is gas-dynamics emission. As for the former, Knudsen layer relationship is employed to calculate the ablation mass; and for the latter, the conservation laws associated with the Jouguet condition are used. Based on the model, the quantitative results of ablation mass, ablation temperature, product component and mass rate of different ablation mechanisms vs. laser fluence are achieved and analyzed, which are consistent with the experimental data quite well.
Solitary wave solution for a class of dusty plasma
Authors: Ouyang Cheng  , Yao Jing-Sun  , Shi Lan-Fang  , Mo Jia-Qi  ,   Huzhou Teachers College, Huzhou 313000, China;,   Department of Mathematics, Anhui Normal University, Wuhu, 241003, China;,   College of Mathematics and Statistics, Nanjing University of Information Science & Technology, Nanjing 210044, China
Published: December 2020

A class of nonlinear solitary waves in dusty plasma is considered. Firstly, a non-disturbed solitary wave solution is stated. Then the iteration is constructed by using the homotopic mapping, and the traveling wave solution of the nonlinear single-disturbed solitary waves in dusty plasma is obtained. Finally, every degree of approximate solutions for corresponding single solitary wave model can be found.
Dynamic fault-tolerance analysis of scale-free topology in wireless sensor networks
Authors: Yin Rong-Rong  , Liu Bin  , Liu Hao-Ran  , Li Ya-Qian  ,   School of Electrical Engineering, Yanshan University, Qinhuangdao 066004, China;,   The Key Laboratory for Special Fiber Sensor of Hebei Province, Yanshan University, Qinhuangdao 066004, China
Published: December 2020

It is very important in practice to avoid cascading failures by increasing the dynamic fault-tolerance of the network. Firstly, a cascading failure model is proposed in this paper, based on the characteristics of the variable load and the fixed capacity of the nodes in wireless sensor network scale-free topology. Then the influences of the load parameter and topology parameters on the fault tolerance are investigated in the case of cascading failure caused by random failure nodes. Finally the critical value of load for the large-scale cascading failure of network is deduced. Simulation result shows that the network's cascading failure fault-tolerance is positively related with the degree parameters, coefficient and power-law exponent. Researches provide regulation to avoid the cascading failure caused by the random failure nodes effectively from optimizing the parameters viewpoint.
study on sensitivity-related parameters of distributed feedback laser-pumped cesium atomic magnetometer
Authors: Gu Yuan  , Shi Rong-Ye  , Wang Yan-Hui  ,   Institute of Quantum Electronics, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, China;,   School of Software and Microelectronics, Peking University, Beijing 100871, China
Published: December 2020

This article reports a distributed feedback (DFB) laser-pumped cesium atomic experimental magnetometer, showing how the sensitivity is influenced by the following 5 kinds of parameters: laser light intensity, laser frequency, radiofrequency intensity, temperature of cesium absorption cell, and the pressure of the buffer gas in the cell. Results of the experiments show that each of the five parameters has some influence on the sensitivity of the magnetometer, especially the laser frequency, radiofrequency intensity, and temperature of cesium absorption cell, which can even improve the sensitivity by 10 times. Recently we have obtained a sensitivity of 2.5 pT/Hz1/2.
A THz polarization splitter made from suspended dual-core porous fiber
Authors: Li Shan-Shan  , Chang Sheng-Jiang  , Zhang Hao  , Bai Jin-Jun  , Liu Wei-Wei  ,   Institute of Modern Optics, Nankai University, Tianjin 300071, China;,   School of Electronics and Information Engineering, Tianjin Polytechnic University, Tianjin 300387, China
Published: December 2020

A low loss broadband THz polarization splitter made from suspended dual-core porous fiber is proposed. The property of low loss is due to the porous structure of the fiber, and the match of single polarization mode is achieved by the orthogonal relationship of the microstructure in the two fiber cores. Structure of the fiber is designed by using index converse matching coupling method. Numerical simulation is carried out by employing full vector finite element method. The background material is cyclo olefin polymer COC with low loss property in THz region. Firstly, the properties of a suspended porous fiber with a single core has been analyzed in detail, including the effective refractive index, birefringence, fraction of modal power in air, and material absorption loss in the fundamental mode. Moreover, the properties of THz polarization splitter made from suspended dual-core porous fibers have been investigated theoretically. Numerical simulation results show that the operation bandwidth is 1.5 THz (from 0.8 THz to 2.3 THz). At 1 THz, the splitting length is only 0.66 cm. The extinction ratios for x and y polarization modes can reach -14.64 dB and -14.84 dB, respectively. The practical material absorption loss is less than 0.12 dB for both x and y polarization modes. Compared with other dual-core-PCF-based polarization splitters, the dual-core porous fiber has several advantages such as simplicity for structure designing, ease of fabrication, better feasibility in practical applications, low transmission loss, and wide operation frequency bandwidth.
Research of classification of cloud and aerosol using multi-axis differential optical absorption spectroscopy
Authors: Wang Yang  , Wagner Thomas  , Li Ang  , Xie Pin-Hua  , Wu De-Xia  , Chen Hao  , Mou Fu-Sheng  , Zhang Jie  , Xu Jin  , Wu Feng-Cheng  , Liu Jian-Guo  , Liu Wen-Qing  , Zeng Yi  ,   Key Laboratory of Environmental Optical & Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China;,   Max-Planck Institute for Chemistry, Mainz, Germany, D-55128
Published: December 2020

The classification of cloud and aerosol by means of multi-axis differential optical absorption spectroscopy (MAX-DOAS) is studied in this paper. Firstly, the characters of variation of color index (CI), radiance, and O4 air mass factor (AMF) are analyzed in the following kinds of weather cases, i.e. clear and low aerosol load, clear and high aerosol load, broken cloud, continuous and thin cloud as well as continuous and thick clouds. We found that the CI consecutively decreases with the growing up of optical depth of cloud and aerosol. And the speedy temporal variation of CI is always going along with the occurrence of broken cloud. For the case of continuous cloud, the CIs of observations for all the elevation angles are similar to each other. At the same time, the thick cloud case normally causes radiance dropping and O4 AMF growing up strongly. Based on these characters, the scheme of cloud classification for MAX-DOAS is built. Using this scheme, the classification results for the MAX-DOAS observations in the period from 1 June 2012 to 30 October 2012 are analyzed statistically. The occurrence probabilities of the broken cloud and thin continuous cloud are the two largest weather kinds. The percentage of the broken cloud in all the observations is 66%, and that of the thin continuous cloud case is 14.3%. For these two kinds of weathers, the mean NO2 tropospheric vertical column densities (VCD) are respectively 35% and 66% larger than the value for the clear and low aerosol. Meanwhile, the standard deviation, which represents the stability of the measured NO2 VCD is two times larger than that of the clear and low aerosol cases. In the weather of thick continuous cloud, suddenly appearing of peak and valley are often observed. In conclusion, the real time classification of cloud and aerosol is very important and valuable in analyzing of MAX-DOAS data and the guarantee of data quality.
A density functional theory study of small bimetallic PdnAl (n =18) clusters
Authors: Wen Jun-Qing  , Zhang Jian-Min  , Yao Pan  , Zhou Hong  , Wang Jun-Fei  ,   College of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062, China;,   College of Science, Xi'an Shiyou University, Xi'an 710065, China;,   Institute of Modern Physics, Northwest University, Xi'an 710069, China
Published: December 2020

Geometries, stabilities, and polarizations of PdnAl(n=18) have been calculated using the density functional theory at BPW91/LANL2DZ level. The growth pattern for different sized PdnAl(n=18)clusters is of Al-substituted Pdn+1 clusters, which shows the similar configuration of most stable Pdn+1 clusters except that of Pd6Al and Pd8Al. Geometries of ground state PdnAl(n=18) clusters keep the same structures of PdnAl clusters except that of Pd2Aland Pd6Al+. Al atoms in the ground state PdnAl and PdnAl isomers tend to occupy the most highly coordinated position. Analysis of stabilities shows that Pd4, Pd3Al and Pd3Al are more stable than other clusters. Study of polarizations shows that Pd-rich clusters have a strong nonlinear optical effect and are easy to be polarized by external electromagnetic field.
All-electron configuration interaction study on potential energy curves of low-lying excited states and spectroscopic properties of SiS
Authors: Li Rui  , Zhang Xiao-Mei  , Li Qi-Nan  , Luo Wang  , Jin Ming-Xing  , Xu Hai-Feng  , Yan Bing  ,   (Department of Physics, College of Science, Qiqihar University, Qiqihar 161006, China),   (Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China)
Published: December 2020

The 18 -S states correlated to the lowest dissociation (Si(3Pg)+S(3Pg)) limit are computed with high-level multireference configuration interaction (MRCI(SD)) approach through utilizing all-electron aug-cc-pwCVQZ-DK basis set. The scalar relativistic effect and the core-valence correlation effect of Si (2s22p6) and S (2s22p6) are taken into account. On the basis of calculated potential energy curves, the spectroscopic constants of the bound states are fitted, including equilibrium distance Re, adiabatic transition energies Te, harmonic vibrational frequencies e, anharmonic terms exe, and rotational constant Be. The electronic configurations at different bond lengths are given. The electronic dipole moments of 18 -S states are calculated, illuminating the influence of electronic configuration variation on electronic dipole moment. With the help of nonvanishing spin-orbit matrix elements including b3 and A1 as a function of the internuclear distance, the nearby state perturbations to b3 and A1 are discussed in detail. Finally, the transition dipole moments and Franck-Condon factors of A1X1+ and E1+X1+ transitions are obtained, and radiative lifetimes of five lowest vibrational levels of the two singlet excited states are evaluated.
A solid-liquid-gas three-phase complete equation of state of aluminum
Authors: Yu Ji-Dong  , Li Ping  , Wang Wen-Qiang  , Wu Qiang  ,   Laboratory for Shock Wave and Detonation Physics Research, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900, China
Published: December 2020

Based on the GRAY equation of state (EOS), we establish a solid-liquid-gas three-phase complete EOS, and compare it with the experimental isothermal compression data, Hugoniot data, melting data and thermodynamic functions under ambient pressure. It is indicated that the EOS in this paper can describe reasonably the thermodynamic state of aluminum in a wide region.
Preparation of GaN nanowires by nonammonia method and their photoelectronic properties
Authors: Zhao Jun-Wei  , Zhang Yue-Fei  , Song Xue-Mei  , Yan Hui  , Wang Ru-Zhi  ,   Laboratory of Thin Film Materials, College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China;,   Institute of Solid State Microstructures and Properties, Beijing University of Technology, Beijing 100124, China
Published: December 2020

Single-crystal hexagonal wurtzite GaN nanowires were successfully synthesized by using plasma-enhanced chemical vapor deposition (PECVD) via vapor-liquid-solid (V-L-S) mechanism, under the condition of non-ammonia at 1050 ℃. Raman spectra show that the as-synthesized nanowires have large disorder surface, in which there is a significantly small size effect. Furthermore, it is also observed that the prepared nanowires have typical photoluminescence characteristics and good field emission properties.
Global proportional fairness scheduling algorithm based on spectrum aggregation in cognitive radio
Authors: Yin Cong  , Tan Xue-Zhi  , Ma Lin  , Yu Yang  ,   Communication Research Center, Harbin Institute of Technology, Harbin 150080, China
Published: December 2020

In a cognitive radio system, it is still a problem that resource scheduling among secondary users (SUs) is distributed unfairly when spectrum aggregation technology is involved to support high-speed data transmission. A global proportional fair scheduling algorithm is proposed based on spectrum aggregation to solve the problem. This paper focuses on the relation between the fairness for SUs and spectrum aggregation. Throughput fairness can be guaranteed as much as possible after considering two parameters, the span of spectrum aggregation and the remaining data queue length of SUs. Simulation results show that the proposed scheduling algorithm takes advantage of fairness and the delay of system service as compared with the other two scheduling algorithms, max C/I and partial proportional fairness. Meanwhile, it is shown that the proposed scheduling algorithm has lower throughput shake to make sure of fairness among SUs and high efficiency of system.
Multiple sites HFSWR ocean shallow water depth and current inversion
Authors: Li Lun  , Wu Xiong-Bin  ,   Wuhan Digital Engineering Institute, Wuhan 430074, China;,   Electronic Information Institute of Wuhan University, Wuhan 430072, China
Published: December 2020

In order to extract the ocean dynamic parameters from shallow water, water depth, and current inversion at multiple (three or more) sites, HFSWR (high frequency surface wave radar) sea echo is developed. In this paper the inversion principle and theoretical model are presented in detail, and the proposed idea is verified for three or more than three sites, which shows prospects in practice. By analyzing the data collected from three HFSWR detection experiments in northern Jiangsu province, the inversion results show good performance, which is promising for extracting ocean water depth in inner zone and shallow water by HFSWR in engineering application.
Dual-origin coordinate system for solar cells
Authors: Zhang Zhong-Zheng  , Cheng Xiao-Fang  ,   Department of Thermal Science and Energy Engineering, University of Science and Technology of China, Hefei 230026, China
Published: December 2020

Photo-generated current is important in solar cell current equation. The value of photo-generated current cannot be labeled in the conventional single origin coordinate system, and a novel dual-origin coordinate system is designed. This article provides a process in how to mark the Kirchhoff's law in a dual-origin coordinate system; besides, the current items (photo-generated current, diode current, shunt resistance current) and the voltage items (diode voltage, series resistance voltage) are also shown. A dual-origin coordinate system clearly points out that the difference between photo-generated current and short-circuit current will increase with increasing short-circuit current. This difference can be ignored only in low light, but it must be considered in high light. The proportions of output power and internal friction power may change with photo-generated current. Assuming that the output power is greater than the internal friction power, the solar cell should not be used to work under high light. A dual-origin coordinate system can provide an adaptation for solar cell study.
Application of digital filter weak constraint four dimensional variational data assimilation on typhoon initialization I. Numerical experiments
Authors: Zhong Jian  , Fei Jian-Fang  , Cheng Xiao-Ping  , Sun Yi-Mei  , Shi Wei  ,   China Satellite Maritime Tracking and Control Department, Jiangyin 214431, China;,   Joint Laboratory of Ocean-based Flight Vehicle Measurement and Control, China Satellite Maritime Tracking and Control Department, Jiangyin 214431, China;,   Institute of Meteorology and Oceanography, PLA University of Science and Technology, Nanjing 211101, China
Published: December 2020

Traditional four-dimensional variational (4D-Var) bogus data assimilation (BDA) will upset the internal dynamical balance of wind and mass fields, which will generate spurious fast oscillations in the prediction and cause the numerical simulation failure. How to effectively suppress the spurious fast oscillations is very important. In this paper (part I), the digital filter weak constraint 4D-Var is tested in BDA experiments. Initialization and simulation experiments are conducted for typhoon Chaba (2010) using this approach. Results show that the initial noise property is different for typhoon case and rainfall case, and the difference in surface pressure tendency is small in assimilation time and large at the initial stage in different digital filter weight setting BDA experiments. The vertical velocity field of 700 hPa and divergence field of 850 hPa in typhoon areas are both weakened in digital filter weak constraint 4D-Var experiments. Compared with the traditional 4D-Var experiment, the track and intensity predictions are improved obviously in digital filter weak constraint 4D-Var experiment with a proper digital filter weight setting, and the track prediction is apparently improved. Meanwhile, the optimal digital filter weight for different typhoon cases is different, and how to optimally select the digital filter weight is very important. In Part Ⅱ, a digital filter weight selection method will be proposed for BDA experiment.
Effect of rocket flame on high-frequency echo and its frequency energy agglomerated detection method
Authors: Wu Xia  , Chen Jian-Wen  , Bao Zheng  , Guo De-Yang  ,   Key Laboratory for Radar Application Engineering, Air Force Early-Warning Academy, Wuhan 430019, China
Published: December 2020

According to the problem that the mass matter from rocket flame consumes the electron density in atmosphere and disturbs high-frequency electromagnetic wave propagation, based on the characteristic of high-frequency radar echo from rocket flame, this paper reports the physical mechanism of high-frequency electromagnetic wave attenuation and flame electromagnetic characteristics, and analyses the radar cross section characteristic of the flame and the procreant time of flame's high-frequency echo. Then the detection method of frequency energy agglomerated for flame is put forward. By simulation analysis and experimental observation, the relations among flame high-frequency echo, altitude, flame electromagnetic characteristic, electric wave frequency, angle of incidence are obtained. The detection method is reliable and can decrease false-alarm and missing-alarm.
New infinite sequence soliton-like solutions of Camassa-Holm-r equation
Authors: Taogetusang  , Yi Li-Na  ,   College of Mathematical Science, Inner Mongolia Normal University, Huhhot 010022, China
Published: December 2020

The method of combining function transformations with auxiliary equation is presented to search for new infinite sequence soliton-like solutions of Camassa-Holm-r (CH-r) equation. And many new conclusions are obtained. Step one,according to some function transformations, CH-r equation is changed into the solvable ordinary differential equation. Step two, new infinite sequence soliton-like solutions of CH-r equation are constructed by applying new solutions and Bäcklund transformation of the solvable ordinary differential equation.
Quantum speech multi-band excitation algorithm
Authors: Liang Yan-Xia  , Nie Min  , Liu Xin  , Zhang Mei-Ling  , Jiang Jing  ,   School of Telecommunication and Information Engineering, Xi'an University of Posts and Telecommunications, Xi'an 710121, China;,   Xi'an Research and Development Center, ZTE Corporation, Xi'an 710065, China
Published: December 2020

Multi-band excitation (MBE) algorithm in classical communication is applied to quantum communication. The corresponding relation between classical information and quantum information is proposed, and the quantum measurement of information is presented. Simulations of quantum MBE algorithm by C language programming demonstrate that the wave of synthesized speech is similar to the original one. An MOS score of 3.337 is obtained from the Perceptual Evaluation of Speech Quality software.
Noise-enhanced information transmission of a non-linear multilevel threshold neural networks system
Authors: Li Huan  , Wang You-Guo  ,   College of Science, Nanjing University of Posts and Telecommunications, Nanjing 210023, China
Published: December 2020

In this paper, (supra-threshold) stochastic resonance phenomenon of noise-enhanced information transmission is studied in detail through the numerical calculation and the computer simulation in a non-linear multilevel threshold neural networks system, which is affected by both additive noise and multiplicative noise, then the mutual information is used to characterize the phenomenon. The mutual information as a function of additive noise intensity or multiplicative noise intensity brings on convex changes under a suitable system threshold and a fixed multiplicative noise intensity or additive noise intensity, which shows that the (supra-threshold) stochastic resonance phenomenon occurs. The increases in the number of the system threshold units can enhance the effectiveness of information transmission; the increase of the system threshold can increase the signal components that are under the threshold, and thus the supra-threshold stochastic resonance takes place more easily. In addition, by changing the additive noise intensity the supra-threshold stochastic resonance occurs more easily than by changing the multiplicative noise intensity. The above results show that both the existence of the supra-threshold stochastic resonance and the effectiveness of noise-improved the signal transmission are closely related to multiplicative or additive noise intensity, the number of threshold units, and the system threshold level.
Dynamical study of peak-current-mode controlled synchronous switching Z-source converter
Authors: Xiang Jun-Jie  , Bi Chuang  , Xiang Yong  , Zhang Qian  , Wang Jing-Mei  ,   School of Energy Science and Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China;,   Institute of Electronic and Information Engineering in Dongguan, University of Electronic Science and Technology of China, Dongguan 523808, China;,   State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, China
Published: December 2020

Z-source converter can have a high voltage transmission ratio, reduce the losses of switching devices, and improve the efficiency of the system, etc., because of embedding the Z-source network into the system, which makes it find wide applications in DC conversion, inverters, etc. Nonlinear dynamics of the peak-current-mode controlled synchronous switching Z-source converter is studied for the first time so far as we know. The discrete iterated mapping model under continuous current mode is established, while the effects of the reference current on the stability of the system are analyzed by using the trajectories of eigenvalues, and the steady state operation parameter domain is schemed. Period-doubling bifurcation, border-collision bifurcation, tangent bifurcation and intermittent chaos are found in this converter based on the bifurcation diagram and the Lyapunov exponent diagram, and the evolvement and mechanism of the border-collision bifurcation and chaos are analyzed. Finally, the circuit simulation and the experimental results show that the theoretical analysis is correct. Results obtained indicate that with the increase of the reference current, the peak-current-mode controlled synchronous switching Z-source converter goes from period 1 into period 2 and period 4 through the period-doubling bifurcation, and moves into the intermittent chaos due to the border-collision bifurcation. Then the system exhibits a period-3 behaviour because of the tangent bifurcation. Finally, the converter moves into chaos due to the border-collision bifurcation again.
Potential risk of variable parameter cascade chaos system
Authors: Jin Jian-Guo  , Di Zhi-Gang  , Wei Ming-Jun  ,   College of Sciences, Hebei United University, Tangshan 063009, China;,   College of Information Engineering, Hebei United University, Tangshan 063009, China;,   College of Electrical Engineering, Hebei United University, Tangshan 063009, China
Published: December 2020

Lyapunov index is one of criteria for testing whether the system is in a chaotic state, and its value represents the developed level of system chaotic state. To study the Lyapunov index characteristic of cascade chaotic system and reveal disturbance mechanism among subsystems in cascade chaotic system, the following researches are carried out. First, the disturbance model among subsystems is constructed from the viewpoint of pseudo noise disturbance, Lyapunov index difference between without and with external noise influence is investigated. Then the conclusion that disturbances among subsystems can be considered as pseudo noise influence is drawn. Second, the conclusion is proved that cascade system Lyapunov index is not the algebraic sum of each independent subsystems, but the one of each subsystems which consist of pre disturbances. Then taking the logistic representation for example, nine cascade systems are designed to prove this conclusion. And some novel characteristics and phenomena are found from the above investigations. They are (a) the phenomenon of “more is less”, that is, Lyapunov index will decrease with the increase of cascade levels, and the phenomenon of “A miss is as good as mile”; (b) even each independent subsystems is chaotic, the cascade system needs not to be chaotic; conversely, even each independent subsystems is not chaotic, the cascade system may be chaotic; (c) whether the cascade system is chaotic is associated with the order of subsystem. Finally, it is pointed out that cascade level has the influences of pros and cons on cascade system, thus revealing the latent hazard of parametric cascade chaotic system. The research result can provide important theoretic foundation for system security and the scientific evaluation of encryption keys.
Fuzzy identification of γ ray fingerprints based on adaptive network-based fuzzy inference system
Authors: Wang Chong-Jie  , Liu Yuan-Yuan  , Zhang Bo-Chao  , Zhang Qian-Ni  , Liu Jin-Yan  , Jin Ge  , Zhang Min  ,   College of Physics and Electric Technology, Liaoning Normal University, Dalian 116029, China
Published: December 2020

An identification method of γ-ray fingerprints based on adaptive network-based fuzzy inference system is brought forward. By setting up model and performing simulation, the parameters of the system relevant to the γ-ray fingerprints are extracted as the identification features. The two-dimensional fuzzy set about the identification features is put forward, and the fundamental principle for identification is established. The types and the individuals of nuclear materials are identified successfully with high degree of confidence. The simulation materials as radiation sources are identified with the method, and the performance of the method is studied and discussed. The results show that the method has not only strong capabilities for identifying the types and the individuals of the radiation sources, but also strong de-noising capability and low identification limit, and it can be applied to the nuclear materials safeguard.
A kind of shared aperture radar absorbing material with absorber and phase cancellation characteristics
Authors: Li Wen-Qiang  , Gao Jun  , Cao Xiang-Yu  , Yang Qun  , Zhao Yi  , Zhang Zhao  , Zhang Cheng-Hui  ,   School of Information and Navigation of Air Force Engineering University, Xi'an 710077, China
Published: December 2020

A method of designing a kind of shared aperture radar absorbing material (SA-RAM) is presented, in which method the scattering problem of passive metamaterial (MTM) is converted into the radiation problem of active array. Multifunctional SA-RAM is realized by optimizing the position, amplitude, and phase of the MTM subarray composed of finite MTM structures based on the array theory. An SA-RAM with absorber and phase cancellation characteristics is fulfilled by interleaving artificial magnetic conductor (AMC) subarray and perfect metamaterial absorber (PMA) subarray. Simulation and experimental results demonstrate that the backscattering radar cross section (RCS) of SA-RAM is smaller than that of the metal plate in a frequency range of 5.5-8.3 GHz. Especially, the RCS reduction is caused by high absorbance at 5.54 GHz and by phase cancellation between AMC subarray and PMA subarray at 7.0 GHz. The idea can help to design radar absorbing material, which combines frequency stealth with space stealth function.
Equivalent modeling method of printed circuit board interference source based on magnetic dipole array
Authors: Cao Zhong  , Du Ping-An  , Nie Bao-Lin  , Ren Dan  , Zhang Qi-Dao  ,   School of Mechatronics Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China
Published: December 2020

In view of the need of the electromagnetic compatibility analysis in the design process of the electronic equipment, an equivalent method of modeling the characteristics of electromagnetic radiation from printed circuit board interference source is proposed by using magnetic dipole array. According to the characteristics of the electromagnetic boundary value problems, the radiating source and the structures affecting the radiation are modeled separately. At first, the actual source is modeled in detail. Then the effect of surrounding structures on the overall radiation is incorporated into the model. Moreover, the basic ideas of equivalent modeling are introduced, and the derivation of the formulas to obtain the magnetic dipole array is given. Finally, a patch antenna is used to demonstrate the validity of the method. The results show that the equivalent modeling method significantly reduces the complexity of the model, the modeling time, and the computational burden.
Vibrational distribution of H2 (D2 and T2) molecules in low temperature plasma
Authors: He Man-Li  , Wang Xiao  , Zhang Ming  , Wang Li  , Song Rui  ,   PLA University of Science and Technology, Nanjing 210007, China
Published: December 2020

In edge plasma, hydrogen molecules have considerably high density. The vibrational distribution of hydrogen can be changed via collisions with plasma. In this paper, various processes of hydrogen molecules are discussed and newest cross section data are adopted while the unavailable data are calculated by semi-classical Gryzinski method. Based on the quasi-stationary approximation and the quasi-steady collisional-radiative model, the vibratioanl distribution of hydrogen in low temperature are studied. The results show that at lower vibrational level, the distribution decreases with the increase of electron temperature when the electron temperature is less than 10 eV. On the other hand, the distribution presents an opposite trend at high vibrational level.
Application of dual-polarization frequency-modulated microwave reflectometer to J-TEXT tokamak
Authors: Zhang Chong-Yang  , Liu A-Di  , Li Hong  , Chen Zhi-Peng  , Li Bin  , Yang Zhou-Jun  , Zhou Chu  , Xie Jin-Lin  , Lan Tao  , Liu Wan-Dong  , Zhuang Ge  , Yu Chang-Xuan  ,   Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China;,   School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
Published: December 2020

A dual-polarization frequency-modulated continuous-wave (FMCW) reflectometer is established on J-TEXT for measuring density profile. The frequency of reflectometer covers both Q band and V band. In order to measure wider density range, ordinary mode polarization and extraordinary mode polarization are utilized at the same time. For the FMCW reflectometer, temporal resolution depends on sweeping rate of the microwave source. Benefited from HTO (hyperabrupt varactortuned oscillator) source, a full frequency sweep period of the reflectometer could be less than 40 μs. Electron density profile from 0-6.0×1019 m-3 can be detected, which covers the whole low field side in J-TEXT. To reconstruct the full density profile, the position of the zero density should be confirmed first, which is determined from where the intermediate frequencies change transiently. Meanwhile, we observe the propagation of left-hand extraordinary wave from data in X-mode reflectometer.
Basic characteristics of kinetic energy transfer in the dynamic hohlraums of Z-pinch
Authors: Ning Cheng  , Feng Zhi-Xing  , Xue Chuang  ,   Beijing Institute of Applied Physics and Computational Mathematics, Beijing 100088, China;,   Beijing Graduate School of China Academy of Engineering Physics, Beijing 100088, China
Published: December 2020

The applications of Z-pinch are realized through dynamic hohlraum driven by Z-pinch, in which a uniform and symmetrical radiation field may be produced for ablating implosion of the inertial confinement fusion (ICF) capsule, and the radiation sources may also be created for heating and backlighting the samples in opacity measurement experiments. The radiation field is essentially related to driven current, hohlraum configuration and material. In physics it is determined by energy transfer in the hohlraum. For rapidly obtaining the knowledge about the primary energy transfer chracteristics in the hohlraum, and its trends of variation in the configuration, linear mass of the load, and the driven current, the simplified model is used to simulate the dynamic hohlraum implosion. The obtained implosion kinetic energy of the cylindrical foam accords well with the kinetic energy obtained from a one-dimensional magneto radiation hydrodynamics simulation of Z-pinch-driven dynamic hohlraum. In the dynamic hohlraum for ICF the kinetic energy loss is important for the radiation field formation when the imploding wire-array plasma collides with the cylindrical foam, while ones for radiation source the kinetic energy loss and for the final implosion kinetic energy of the foam are both important. The maximum implosion kinetic energy of cylindrical foam is directly proportional to the square of the peak current, while the kinetic energy loss increases with the mass of cylindrical foam increasing. The mass energy density in the foam tends to increase, and in turn the radiation power is enhanced when the rise time of the current turns longer.
Diagnoses of Au plasma with soft X-ray double frequency grating interference technique
Authors: Wang Chen  , An Hong-Hai  , Wang Wei  , Fang Zhi-Heng  , Jia Guo  , Meng Xiang-Fu  , Sun Jin-Ren  , Liu Zheng-Kun  , Fu Shao-Jun  , Qiao Xiu-Mei  , Zheng Wu-Di  , Wang Shi-Ji  ,   Shanghai Institude of Laser Plasma, Shanghai 201800, China;,   National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China;,   Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
Published: December 2020

The diagnoses of laser-produced plasma electron density have important significance for inertial confinement fusion, plasma physics, high energy density physics and other relevant fields, especially for measuring electron density distribution information of medium and high-Z material plasma near the critical density surface. With 13.9 nm Ni-like Ag X-ray laser serving as a probe, using double frequency grating shearing interference technique, the electron density distribution of plasma produced by laser irradiating a gold planar target is measured. Clear interference fringe image is obtained. Preliminary deduction of the fringe shows that the maximum density measured is about 1.4 times the critical density. It is found that there are some discrepancies between experimental results and simulation results, which provides a useful reference to the further optimization of the simulation program. The experimental results fully demonstrate that the soft X-ray double frequency grating shearing interference technique is practical to diagnose near-critical-density plasma of medium and high-Z materials, which will have a good application value.