bluuebunny/crossref_metadata_2025 huggingface dataset:
Powders (Sb2Te3)0.75(1－x)(Bi2Te3)0.25(1－x)(Sb2Se3)x prepared by mechanical alloying and thermoelectric properties of cold-pressed and s
Authors: Hu Jian-Min  , Xin Jiang-Bo  , Lü Qiang  , Wang Yue-Yuan  , Rong Jian-Ying  ,   (1)哈尔滨师范大学阿城学院物理系，阿城  150301; (2)哈尔滨师范大学物理系，哈尔滨  150025; (3)哈尔滨师范大学物理系，哈尔滨  150025;哈尔滨师范大学阿城学院物理系，阿城  150301; (4)哈尔滨师范大学物理系，哈尔滨  150025;牡丹江医学院电子技术教研室，牡丹江  157011
Published: December 2020

The powders of p-type pseudo-ternary Sb2Te3-Bi2Te3-Sb2Se3 thermoelectric materials prepared by mechanical alloying method were analysed by XRD, with Te，Bi，Sb and Se element granules alloyed after 100h ball milling. The alloyed powders were analysed by SEM, showing granules of fine powders about 10—100nm in size. Blocks of p-type pseudo-ternary thermoelectric materials were prepared with the powders by cold-pressing and sintering. Seebeck coefficient and electrical conductivity for samples with different sintering temperatures were measured at room temperature. The results suggest that thermoelectric properties gradually improve with sintering temperatures during 300℃, the power factor enhances from 0.59μW cm-1K-2 of unsintered samples to 15.9μW cm-1K-2 of samples sintered at 300℃. So the result might play an important role in optimizing sintering temperature.
Dependence of thermoelectric properties of n-type Bi2Te3-based sintered materials on the TeI4 doping content
Authors: Jiang Jun  , Xu Gao-Jie  , Cui Ping  , Chen Li-Dong  ,   (1)中国科学院宁波材料技术与工程研究所，宁波  315040; (2)中国科学院上海硅酸盐研究所高性能陶瓷和超微结构国家重点实验室，上海  200050
Published: December 2020

N-type (Bi2Te3)0.93(Bi2Se3)0.07 thermoelectric materials doped with various content of TeI4 (0, 0.05, 0.08, 0.10, 0.13, and 0.15wt%) have been fabricated through the combination of zone melting and spark plasma Sintering. Electrical conductivity (σ), Seebeck coefficient (α) and thermal conductivity (κ) were measured in the temperature range of 300—500K. The influence of the variation of TeI4 content on thermoelectric properties was studied. The increase of TeI4 content caused an increase of carrier concentration and thus resulted in an increase of σ and a decrease of α, and the lattice thermal conductivity was decreased by the increase of phonon scattering resulting from heterogeneous ion (I) scattering and carrier scattering. The maximum figure of merit ZT (ZT=α2σT/κ) of the sintered materials in the direction perpendicular to the pressing direction showed a value of 0.92 for the sample containing 0.08wt% TeI4. In addition, the bending strength of the sintered materials was improved to about 80MPa from about 10MPa of the zone-melted ingot, which is of advantage to the fabrication process and the improvement of the reliability for thermoelectric modules.
Polycrystalline CdS/CdTe thin-film solar cells with intrinsic SnO2 films of high resistance
Authors: Zeng Guang-Gen  , Zheng Jia-Gui  , Li Bing  , Lei Zhi  , Wu Li-Li  , Cai Ya-Ping  , Li Wei  , Zhang Jing-Quan  , Cai Wei  , Feng Liang-Huan  ,   四川大学材料科学与工程学院，成都  610064
Published: December 2020

Intrinsic SnO2 films as the high resistance transparent (HRT) layers are prepared by ultrasonic spray pyrolysis and used in CdS/CdTe solar cells with a thin CdS layer. XRD and AFM are used to study the performance of the thin CdS layers. The illuminated and dark I-V characteristics, spectral response (SR) and C-V characteristics of the devices are measured. The results show that the thin CdS films deposited on HRT layers have an obvious preferred orientation along (111) plan. But pinholes are formed when using a thin CdS layer. After introducing the HRT layer, the tunneling leakage caused by the pinholes can be avoided, which effectively protects the p-n junction. Meanwhile, higher shunt resistivity, fill factor, short-wave response, carrier concentration and lower dark saturation current density have been achieved. As a result, the conversion efficiency is enhanced by 14.4%.
Effect of Fe and Co in ferromagnetic shape memory alloy Mn50Ni25－xFe(Co)xGa25
Authors: Liu Guo-Dong  , Wang Xin-Qiang  , Dai Xue-Fang  , Liu Zhu-Hong  , Yu Shu-Yun  , Chen Jing-Lan  , Wu Guang-Heng  ,   (1)中国科学院物理研究所磁学国家重点实验室，北京  100080; (2)重庆大学数理学院，重庆  400044; (3)重庆大学数理学院，重庆  400044;中国科学院物理研究所磁学国家重点实验室，北京  100080
Published: December 2020

The ferromagnetic shape memory alloy Mn2NiGa was developed recently. In order to improve the properties of this material and develop new ferromagnetic shape memory alloys, in this work an experiment of partially substituting Fe or Co for Ni in Mn2NiGa alloys was carried out to examine the effect of Fe or Co in quaternary Mn50Ni25-xFe(Co)xGa25 alloys on their structure, magnetic properties, martensitic transformation, and mechanical properties. Some interesting results were presented in this paper.
Effect of frustration on spin-wave excitation of the quasi-one-dimensional antiferromagnetic chain with asymmetrical sublattices
Authors: Jiang Jian-Jun  , Zhang Song-Jun  , Liu Yong-Jun  ,   扬州大学物理科学与技术学院,扬州  225002
Published: December 2020

The s=1/2 quasi-one-dimensional Heisenberg antiferromagnetic chain with asymmetrical sublattices possesses three branches of spin-wave spectra (one in acoustic mode and the other two in optical mode). The frustration relieves the gap-degeneracy of two optical branches and softens the spectrum in acoustic mode, but doesn't soften the spectra in optical mode. Also, the frustration moves down obviously one of the two spectra in optical mode. It means that the frustration makes the spin-wave excitation described by spectrum in optical mode easier and more important. The status of spin on the chain changes more easily than that of side spin under the effect of frustration. The weakening of magnetic order in ground state becomes strong with the strengthening of frustration. By comparison with numerical results of exact diagonalization and DMRG methods, we discuss the merit and drawbacks of the spin-wave approximation.
Analysis of the negative refraction in two-dimensional photonic crystals with wavy structure
Authors: Li Yi-Yu  , Gu Pei-Fu  , Zhang Jin-Long  , Li Ming-Yu  , Liu Xu  ,   浙江大学现代光学仪器国家重点实验室,杭州  310027
Published: December 2020

The negative refraction phenomenon in wavy two-dimensional (2D) photonic crystals (PC) is investigated with the iso-frequency surfaces of PC and incident medium. The finite-difference time-domain method is used to simulate the negative refraction of incident Gaussian beam with different wavelengths and incident angles. When the incident angle is set at 45 degrees, the linear relation exists between the negative refraction angle and the wavelength within the range from 1485 to 1530nm, which is suitable for the superprism effect. In order to increase the transmission when negative refraction happened at large incident angles, interface projection method is employed.
Microstructure and optical constants of sputtered Ag films of different thickness
Authors: Sun Xi-Lian  , Hong Rui-Jin  , Qi Hong-Ji  , Fan Zheng-Xiu  , Shao Jian-Da  ,   光学薄膜技术研发中心，中国科学院上海精密机械研究所，上海  201800
Published: December 2020

Ag films with different thickness from 8.2nm to 107.2nm were prepared by DC sputtering deposition and analyzed by X-ray diffraction with the help of optimization program on computer. Microstructrue analysis shows that the films are made of fcc-Ag particles. With the increase of thickness, the mean size of Ag particles increases and the interplaner spacing decreases gradually. The optical constants computed by computer program shows that n value decreases quickly with the increasing thickness below 17.5nm and k value changes in reverse, and then go steadily when the thickness is larger than 17.5nm at the wavelength of 550nm.
Electro-optic properties of potassium sodium strontium barium niobate ferroelectric thin films
Authors: Kang Xiang-Zhe  , Ye Hui  ,   浙江大学现代光学仪器国家重点实验室，杭州  310027
Published: December 2020

Fully occupied ferroelectric ((KxNa1-x)0.4(SryBa1-y)0.8, 0.5051 of KNSBN films can be greatly improved by introducing alkali metal ions, the measured values of transverse electro-optic coefficient r51 of K0.2Na0.2Sr0.24Ba0.56Nb2O6, K0.2Na0.2Sr0.6Ba0.2Nb2O6, K0.2Na0.2Sr0.72Ba0.08Nb2O6 are 108.52pm/V, 119.98pm/V, and 126.96pm/V, respectively. An enhancement of r51 with Sr2+content in KNSBN films has been demonstrated.
Investigation of high hole concentration Mg-doped InGaN epilayer
Authors: Liu Nai-Xin  , Wang Huai-Bing  , Liu Jian-Ping  , Niu Nan-Hui  , Zhang Nian-Guo  , Li Tong  , Xing Yan-Hui  , Han Jun  , Guo Xia  , Shen Guang-Di  ,   北京工业大学电子信息与控制工程学院,北京市光电子技术实验室,北京  100022
Published: December 2020

We investigated the optical and electrical properties of Mg-doped InxGa1-xN(0≤x≤0.3) grown by metalorganic chemical vapor deposition with different In and Mg contents. When the Mg doping concentration was fixed, the hole concentration of samples increased remarkably with the elevation of In mole fraction. The highest hole concentration achieved was 2.4×1019cm-3,the doping efficiency increased nearly by two orders. We explained the carrier transition mechanism with the help of the photoluminesce spectra. In addition, we obtained the activation energy of Mg and the band position of deep donor in InGaN:Mg samples.
Quantum Schwarzschild black hole and dark matter
Authors: Liu Liao  , Pei Shou-Yong  ,   北京师范大学物理系，北京  100875
Published: December 2020

If the situation of quantum gravity nowadays is nearly the same as that of quantum mechanics in its early time of Bohr and Sommerfeld, then a first-step study of the quantum gravity under Sommerfeld's quantum condition of action might be helpful. We present the spectra of quantum Schwarzschild black hole in non-relativistic quantum mechanics. It is found that the quantum of area is 8π3l2p, the quantum of entropy is 2π3kB, and the Hawking evaporation will cease when the black　hole reaches the ground state　m=123mp. A very natural conjecture is that the constituents of dark matter may come from the remnant (relics) of primordeal black hole with life time smaller than that of the universe.
The generalized uncertainty relation and Dirac field entropy of black hole with an internal global monopole
Authors: Han Yi-Wen  , Hong Yun  , Yang Shu-Zheng  ,   (1)西华师范大学理论物理研究所，南充  637002; (2)重庆工商大学理学院，重庆  400067
Published: December 2020

The generalized uncertainty relation is considered in the new equation of state density. Using the WKB approximation, Dirac field entropy of the horizon of the black hole with an internal global monopole is calculated directly. The result shows that the black hole entropy is proportional to the horizon area, which brings to light the relationship between the black hole entropy and the entropy of quantum state near the event horizon. The difference from the brick-wall model is that the present result is convergent without any cutoff. It is indicated that this method can be used to calculate the entropy of the scale field of black hole, and it can be extended to calculate the entropy of Dirac field.
Molecular dynamics simulation of formation of silicon nanoparticles on surfaces of carbon nanotubes
Authors: Meng Li-Jun  , Zhang Kai-Wang  , Zhong Jian-Xin  ,   湘潭大学材料与光电物理学院,湘潭  411105
Published: December 2020

In this paper, we have studied the formation of silicon nanoparticles on surfaces of carbon nanotubes by molecular dynamics simulation. We found that, due to the Si-nanotube interaction and the enormous curvatures of carbon nanotubes, Si atoms on the surface of a carbon nanotube prefer to form a three-dimensional nanoparticle rather than a thin film covering the nanotube.Small Si nanoparticles have similar atomic structures as are found in Si nanoparticles grown without any substrate.Large Si nanoparticles are elongated in the axial direction of the nanotube and have amorphous network structures of Si，different from the crystalline structure of Si nanoparticles without considering Si-nanotube interaction.
Amplitude control of limit cycle of coupled van der Pol oscillator
Authors: Tang Jia-Shi  , Xiao Han  ,   湖南大学力学与航空航天学院，长沙  410082
Published: December 2020

Feedback controllers are designed by way of controlling the amplitude of limit cycle of coupled van der Pol oscillators. Bifurcation control equations of weakly nonlinear systems are obtained by using the approximate method, and relationships between the amplitude of limit cycle and the control gain are acquired, hence the amplitude of limit cycle can be controlled effectively. By using numerical method of solving ordinary differential equations, time displacement curves and limit cycle of the uncontrolled or controlled system can be found. The results obtained by approximate method and in numerical calculation are in good agreement. The method may be applied to other coupled van der Pol oscillators.
Effect of dry etching on light emission of InAsP/InP SMQWs
Authors: Cao Meng  , Wu Hui-Zhen  , Liu Cheng  , Lao Yan-Feng  , Huang Zhan-Chao  , Xie Zheng-Sheng  , Zhang Jun  , Jiang Shan  ,   (1)武汉邮电科学研究院，武汉  430074; (2)中国科学院上海微系统与信息技术研究所信息功能材料国家重点实验室，上海  200050; (3)中国科学院上海微系统与信息技术研究所信息功能材料国家重点实验室，上海  200050；中国科学院研究生院，北京  100039
Published: December 2020

The cap layers of InAsP/InP SMQWs and InAsP/InGaAsP strained single quantum wells (SSQW) are etched to different depths using ICP. The PL intensity of the quantum wells is enhanced by different degrees after dry etching. The quantum well surface becomes rough and the microstructure inside the quantum well is changed during dry etching. The influence of surface roughness to the photoluminescence of quantum well is eliminated by selectively wet etching the InP cap layer of the SSQW. It is attained that after the cap layer is dry etched off about 20 nm the PL intensity of SSQW is enhanced about 1.8 and 1.2 times due to the change in microstructure and the roughening of surface, respectively.
The oxidation characteristics of InN films
Authors: Xie Zi-Li  , Zhang Rong  , Xiu Xiang-Qian  , Liu Bin  , Zhu Shun-Ming  , Zhao Hong  , Pu Lin  , Han Ping  , Jiang Ruo-Lian  , Shi Yi  , Zheng You-Dou  ,   南京大学物理系，江苏省光电功能材料重点实验室，南京  210093
Published: December 2020

The characteristics of oxidation of InN film in different oxygen atmosphere have been investigated. At the temperature under 400 ℃, the oxidation of InN film is difficult, but the oxidation of metal In is very easy. Thus, the oxidation of In is the main process during oxidation of the In-rich InN film under the temperature less than 400 ℃. As the annealing temperature is higher than 400 ℃, metal In and InN are oxidated meanwhile. Although oxidation under the temperature high than 400 ℃, InN is apparently oxidated very slowly. This may be due to the decomposition of InN. The oxidation rate under the ambience of wet oxygen is larger than that under dry oxygen.
First-principles study of the electronic structure of N-doping anatase TiO2
Authors: Xu Ling  , Tang Chao-Qun  , Dai Lei  , Tang Dai-Hai  , Ma Xin-Guo  ,   华中科技大学物理系,武汉  430074
Published: December 2020

In order to investigate the effect of N-doping on the electronic structure of anatase TiO2,and discover the mechanism of band gap narrowing after N-doping, we have carried out first-principles calculations based on density-functional theory(DFT) for anatase TiO2 system. Studies of band structures and densities of states and densities of electron distributing show that Ti atoms and N atoms at the conduction band(CB) area, happens a kind of strong correlated interaction, which will lead electrons of Ti atom on the 3d orbit to move to 2p orbit of N atom, and the entire conduction band will move to the Fermi level. Band gap will narrow and the Red Shift electrophoresis will happen. Theoretical result has been compared with the experiment result.
Nanostructure and hard magnetic properties of exchange coupled Nd-Fe-B/FeCo multilayer films
Authors: Ao Qi  , Zhang Wa-Li  , Zhang Yi  , Wu Jian-Sheng  ,   上海交通大学，高温材料与高温测试教育部重点实验室，上海  200030
Published: December 2020

The nanocomposite Nd-Fe-B/FeCo mutilayer films have been prepared by rf sputtering. XRD results and HRTEM observation showed that as-deposited films deposited at substrate temperature of 300K were amorphous. The columnar grains of Nd2Fe14B phase with the c-axis perpendicular to the film plane developed after annealing at 923 K for 15 min. Nd2Fe14B grain size was about 10 nm in average and Nd-O particles of about 7 nm were dispersed within the grains and along the grain boundaries. The magnetization of these samples is found to increase with increasing FeCo layer thickness (tFeCo) and the coercivity decreases with increasing tFeCo. The multilayer films of maximum energy product is 200 kJ/m3 for tFeCo=5 nm at room temperature. The enhancement of the remanence and energy product in nanocomposite films is attributed to the exchange coupling between the magnetically hard and soft phases.
Magnetization and susceptibility of diluted magnetic semiconductor Hg0.89Mn0.11Te
Authors: Wang Ze-Wen  , Jie Wan-Qi  ,   西北工业大学材料学院，西安  710012
Published: December 2020

The magnetization measurements of Hg0.89Mn0.11Te sample grown by vertical Bridgman method have been carried out at 5 K under external field from -5200 to 5200 kA/m, and at 800 kA/m from 5 to 300 K with zero-field-cooling and field-cooling respectively using the superconducting quantum interference device (SQUID) magnetometer. Based on the mean field theory, a modified Brillouin function is well fitted with the data of magnetization vs magnetic field over the entire magnetic field range. The analysis indicates that there is an antiferromagnetic exchange coupling between Mn ions. The results of reciprocal susceptibility vs temperature show Curie-Weiss behaviors at temperatures above 40 K and a deviation from the Curie-Weiss law at temperatures from 5 to 40 K, which shows that the antiferromagnetic exchange coupling between Mn ions increases with decreasing temperature. The result was explained by extending higher-order terms in the calculation of susceptibility. Hg0.89Mn0.11Te is a paramagnetic material in temperature range from 5 to 300 K.
Influence of deep level defects on electrical compensation in semi-insulating InP materials
Authors: Yang Jun  , Zhao You-Wen  , Dong Zhi-Yuan  , Deng Ai-Hong  , Miao Shan-Shan  , Wang Bo  ,   (1)四川大学物理学院应用物理系，成都  610065; (2)中国科学院半导体研究所，北京  100083
Published: December 2020

In this paper, we analyze and compare electrical compensation and deep level defects in semi-insulating (SI) materials prepared by Fe-doping and high temperature annealing of undoped InP. Influence of deep level defects in the SI-InP materials on the electrical compensation has been studied thermally stimulated current spectroscopy (TSC). Electrical property of the Fe-doped SI-InP is deteriorated due to involvement of a high concentration of deep level defects in the compensation. In contrast, the concentration of deep defects is very low in high temperature annealed undoped SI-InP in which Fe acceptors formed by diffusion act as the only compensation centre to pin the Fermi level, resulting in excellent electrical performance. A more comprehensive electrical compensation model of SI-InP has been given based on the research results.
Electronic structure and physical properties of γ-Si3N4 under high pressure
Authors: Ding Ying-Chun  , Xu Ming  , Pan Hong-Zhe  , Shen Yi-Bin  , Zhu Wen-Jun  , He Hong-Liang  ,   (1)四川师范大学物理与电子工程学院和固体物理研究所低维结构物理实验室,成都  610068; (2)四川师范大学物理与电子工程学院和固体物理研究所低维结构物理实验室,成都  610068;中国工程物理研究院流体物理研究所冲击波物理与爆轰物理重点实验室，绵阳  621900; (3)四川师范大学物理与电子工程学院和固体物理研究所低维结构物理实验室,成都  610068;重庆邮电学院光电工程学院,重庆  400065; (4)中国工程物理研究院流体物理研究所冲击波物理与爆轰物理重点实验室，绵阳  621900
Published: December 2020

The pressure-dependent electronic structure and physical properties of γ- Si3N4 have been calculated by means of plane wave pseudo-potential method (PWP) using GGA-PW91. Based on the calculations, we analyzed the influence of pressure on the optical and mechanical properties γ-Si3N4, which indicates that γ-Si3N4 is quite suitable for applications under high pressure.
Research on silane depletion status during the deposition of silicon thin films by high-pressure PECVD
Authors: Hou Guo-Fu  , Xue Jun-Ming  , Sun Jian  , Guo Qun-Chao  , Zhang De-Kun  , Ren Hui-Zhi  , Zhao Ying  , Geng Xin-Hua  , Li Yi-Gang  ,   (1)南开大学光电子所，天津  300071；天津市光电子薄膜器件与技术重点实验室，天津  300071；光电信息科学与技术教育部重点实验室(南开大学，天津大学)，天津  300071; (2)南开大学物理学院，天津  300071
Published: December 2020

In this paper a series of hydrogenated silicon thin films were prepared by high-pressure radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) using various plasma powers. The influence of plasma power on Raman crystallinity and deposition rate was investigated to study the silane depletion level during the deposition of silicon thin films. Based on these results the status of silane depletion were classified as un-depleted, depleted and over-depleted status. Additionally, the structural and opto-electrical properties were also investigated for those materials deposited under different silane depletion status. The results demonstrated that the μc-Si:H films, which are deposited at depleted status, have good opto-electrical properties and are suitable for application as intrinsic layers in solar cells.
Equilibrium distribution boundary condition in lattice Boltzmann model and numerical simulation of Darcy-Forcheimer drag for fluid flow across a square cylinder array
Authors: Feng Shi-De  , Zhong Lin-Hao  , Gao Shou-Ting  , Dong Ping  ,   (1)Faculty of Science and Engineering,University of Dundee,DD1 4HN,UK; (2)中国科学院大气物理研究所云降水物理和强风暴实验室和大气科学和地球流体学数值模拟国家重点实验室，北京 100029
Published: December 2020

This article presents a boundary condition for the equilibrium distribution suitable for a variety of non-slip flow Llattice Boltzmann simulations. The boundary condition is based on the Bounce-back method and satisfies mass and momentum conservation principles.The computational results show that the new boundary condition for the equilibrium distribution overcame the erroneous slip velocities resulted from the conventional bounce-back method. The porous flow field around prism-shaped particles which is governed by Darcy-Forcheimer formula is calculated and compared with Lee and Yang's (1997) the predictions are found to be sufficiently reliable.
The q-boson hopping model with integrable open boundary condition
Authors: Li Bo  , Wang Yan-Shen  ,   西安交通大学理学院应用物理系，西安 710049
Published: December 2020

Utilizing the algebraic Bethe Ansatz method, the Hamiltonian of q-boson hopping model and its eigenvalue equation are calculated under the integrable open boundary condition. Our result may serve as a theoretical basis for studying strongly correlated boson systems of still smaller scales.
Discussion on the stratified merit of graded index coatings
Authors: Shen Zi-Cai  , Shen Jian  , Liu Shi-Jie  , Kong Wei-Jin  , Shao Jian-Da  , Fan Zheng-Xiu  ,   (1)中国科学院上海光学精密机械研究所,上海 201800; (2)中国科学院上海光学精密机械研究所,上海 201800;中国科学院研究生院,北京 100049
Published: December 2020

Optical property analysis and preparation of graded index coatings can be approximated by subdividing it into a stack of many homogeneous layers. In this paper, layered medium theory is introduced firstly, which clarifies how to subdivide graded index coatings into homogeneous layers. Then a stratification merit method to get optimal layered number is put forward. At last, linear graded index coatings is taken as an example to illustrate how to obtain the optimal layer number of graded index coatings. Our discussion shows that the optimal layer number of graded index coatings depends on the coating thickness and changing speed of refractive index. When refractive index changes in given range, the layer number of graded index coatings decreases firstly and then increases with the increasing coating thickness.
A possible route of nuclear quantum phase transition induced by rotation
Authors: Shi Zhu-Yi  , Tong Hong  , Shi Zhu-Ya  , Zhang Chun-Mei  , Zhao Xing-Zhi  , Ni Shao-Yong  ,   (1)贵州民族学院物理系,贵阳 550025; (2)贵州民族学院物理系,贵阳 550025;西北第二民族学院基础部,银川 750021; (3)西北第二民族学院基础部,银川 750021
Published: December 2020

Based on the microscopic IBM-theory, a possible route of boson quantum phase transition induced by rotation is put forward. Once the nucleus is in a high-energy excited or high-speed rotating state, the nucleus would occupy the coexist-phase of collective superfluid phase with single-particle phase, if the energy is enough to realize the boson's breaking up and aligning in the nucleus, characterized by a more dense spectrum. If the energy is not enough, either of following two cases will happen. When the rotating state of nucleus arrives at critical rotating-frequency ωc, one case is that a higher-momentum boson may be decoupled from the `collective state' as a quantum `free boson', the other case is that the transition from a higher-momentum boson to a lower-momentum boson takes place, and the nucleus remaius in a collective state.Both cases are acompanied by the light-emission from the transition from higher excited-state to lower excited-state, and the total superfluous band energy of nuclear system is released by means of excited element, and an energy level appears in the ground-state band, which signifies a quantum phase transition. Just owing to these boson quantum phase transition, nuclear quantum phase transition could happen. Descriptions of boson phase transitions on breaking up and aligning as well as on decoupled and released photons have been united in this physical picture. As an example, this model has been expounded with the mechanism of producing 14+1, 14+2, and 14+3 states on the 100Pd nucleus.
Symmetry energy and isospin effects of threshold energy of radial flow in heavy ion collisions
Authors: Bian Bao-An  , Zhou Hong-Yu  , Zhang Feng-Shou  ,   (1)北京师范大学射线束技术与材料改性教育部重点实验室,北京师范大学低能核物理研究所,北京 100875;北京市辐射中心,北京 100875; (2)北京师范大学射线束技术与材料改性教育部重点实验室,北京师范大学低能核物理研究所,北京 100875;北京市辐射中心,北京 100875; 兰州重离子加速器国家实验室原子核理论中心,兰州 730000
Published: December 2020

The threshold energies of radial flow in reactions of 124Sn+124Sn and 124Ba+124Ba in central collisions are investigated within an isospin dependent quantum molecular dynamics model by using three different forms of symmetry energy. It is found that the neutron-rich system has smaller threshold energy of radial flow and its value depends strongly on the form of symmetry energy. It indicates that the threshold energy of radial flow may provide a new method to determine the symmetry energy of nuclear matter.
Study of mass distributions of quasifission products based on dinuclear system
Authors: Jia Fei  , Xu Hu-Shan  , Huang Tian-Heng  , Yuan Xiao-Hua  , Zhang Hong-Bin  , Li Jun-Qing  , W.Scheid  ,   (1)Institute for Theoretical Physics of Justus-Liebig University,Giessen 35392 Germany; (2)中国科学院近代物理研究所,兰州 730000; (3)中国科学院近代物理研究所,兰州 730000;中国科学院研究生院,北京 100049;
Published: December 2020

In the concept of dinuclear system, the quasifission rate from Kramers formula has been incorporated in the master equation in order to study the competition between fusion and qusifission. Mass yields of quasifission products of the three reactions 48Ca+244Pu， 48Ca+238U and 58Fe+232Th have been calculated, and the experimental data are reproduced very well, which is a critical test for the existing fusion model. Also we have shown the time evolution of the mass distributions of quasifission products, which provides valuable information of the process of competition between fusion and quasifission.
Calculation of dielectronic recombination rate coefficients of Kα- and Kβ-type decays of Ni27+
Authors: Mu Zhi-Dong  , Wei Qi-Ying  ,   中国矿业大学理学院,徐州 221008
Published: December 2020

The dielectronic recombination(DR) rate coefficients are investigated for low-density hydrogen-like Ni27+ at plasma temperatures 0.1—10 keV by the wavefunction from Hartree-Fock with relativistic Corrections(HFR) method. Based on the KLn and KMn resonance excitation, the partial DR rate coefficients of the DR processes are calculated by taking into account the important radiative decay tunnel including the Kα- and Kβ-type decays. It was found that the Kα- and Kβ-type radiative decays are important in the DR processes of hydrogen-like Ni27+. The partial DR rate coefficient of Kα processes is much larger than that of Kβ.
THz spectra study of MgF2 crystals
Authors: Hou Bi-Hui  , Shao Meng  , Xu Xin-Long  , Wang Li  , Wang Ji-You  , Fan Zhi-Da  ,   (1)北京工业大学应用数理学院,北京 100022; (2)人工晶体研究院,北京 100018; (3)中国科学院物理研究所光物理国家实验室,北京 100080
Published: December 2020

THz (terahertz) properties of MgF2 crystal (sample 1) and MgF2: Co crystal (sample 2) is measured using transmission THz time domain spectroscopy in the frequency range between 0.5 and 2.5 THz. The absorption coefficients α(ν) of sample 1 increases and has a maximum 24cm-1 with increasing frequency ν from 0.5　THz to 2.5　THz. The absorption coefficient of sample 2 is much larger than that of the sample 1, and its absorption band edge of the crystal lattice shifts to lower frequency side because of the dopant Co. Moreover, there is an absorption peak at 1.9THz and the absorption coefficient is greater than 70 cm-1, the force constant K of F-—Co2+ ionic chemical bond stretch vibration calculated from this peak is 3.40×10-2　N/cm. The THz spectroscopy can be an important technique for research of chemical bond in crystal. Real dielectric functions between 0.5 and 2.5 THz of the two samples are calculated by relations between optical constants. The ε1(ν) of sample 1 varies from 4.67 to 4.73 and ε1(ν) of sample 2 varies from 4.62 to 5.01.
1 kHz-0.1 TW high efficiency Ti: sapphire laser amplifier
Authors: Liu Jun  , Li Xiao-Fang  , Chen Xiao-Wei  , Jiang Yong-Liang  , Li Ru-Xin  , Xu Zhi-Zhan  ,   中国科学院上海光学精密机械研究所,强场激光物理国家重点实验室,上海 201800
Published: December 2020

A Ti:sapphire multipass amplifier with high efficiency at the repitation of 1 kHz is described. The incident 0.66 W pulses are amplified to 7.2 W when the pump power is 23 W. The energy extraction efficiency is about 30%. After compressed in the compressor, we obtained 4.5mJ, 38fs pulses with peak power greater than 0.1 TW.
Experimental and theoretical study of displacement measurement based on frequency modulation optical feedback in a birefringence dual frequency laser
Authors: Mao Wei  , Zhang Shu-Lian  ,   清华大学精密测试技术及仪器国家重点实验室,北京 100084
Published: December 2020

提出了一种基于双折射双频激光器中的调频回馈效应的位移测量系统，并在实验和理论两方面进行了研究.实验中保持回馈外腔长度不变，将一四分之一波片置于激光器内腔中，调制内腔长度，激光器的中心频率发生改变，激光器输出强度将发生周期性的变化.研究发现激光强度曲线的波动频率正比于回馈外腔长度与内腔长度之比.当该位移测量系统的外腔长度是内腔长度的6倍时，被测物体每移动半个光波长，激光强度波动12次，系统分辨率可以达到二十四分之一光波长.理论分析与实验结果相符合.研究表明该位移测量系统具有高分辨率、大测量范围、可工作于任意回馈水平等特点.
Acoustic-phonon transmission in multilayer heterojunctions
Authors: He Meng-Dong  , Gong Zhi-Qiang  ,   中南林业科技大学理学院，株洲 412006
Published: December 2020

Using a transfer matrix method, we investigate the transmission property of the acoustic-phonon modes in symmetrical multilayer heterojunctions consisting of many different heterojunctions (GaAs/AlxiGa1-xiAs) within elastic continuum approximation. Our results show that the oscillation amplitude and frequency are different between transmission curve in such structure and transmission curve in the superlattice (GaAs/AlAs) with the same thicknesses of constituent layers. The features of transmission spectrum are influenced by the distribution of the concentration xi(i denotes the i th AlxiGa1-xiAs slab on both sides of the symmetrical axis) . When the concentration xi in AlxiGa1-xiAs slab decreases with the increase of i, the curve in transmission spectrum is flat except in the vicinity of the main valley. When the concentration xi increases with the increase of i, the oscillation amplitude of the curve increases and the main valley is split. Our results also show that the transmission coefficient is sensitive to the thicknesses of constituent layers, especially the thickness of AlxiGa1-xiAs. In addition, it is found that the number of heterojunctions influences the transmission of acoustic phonon.
Generalized parametric constitutive law for van der Waals force simulation and its applications in computation of nanotubes
Authors: Zhang Hong-Wu  , Wang Jin-Bao  , Ye Hong-Fei  , Wang Lei  ,   大连理工大学工业装备结构分析国家重点实验室，工程力学系，大连 116023
Published: December 2020

In this paper, a parametric variational principle for van der Waals force simulation between any two non-bonded atoms is established together with the corresponding improved quadratic programming method for numerical simulation of mechanical behaviours of carbon nanotubes. Carbon-carbon covalent bond interaction in carbon nanotubes is modeled and computed based on molecular structural mechanics model. Van der Waals force is simulated by the network of bars with a special nonlinear mechanical constitutive law in the finite element analysis. In comparison with conventional numerical methods, the suggested method does not depend on displacement and stress iteration, but on the base exchanges in the solution of a standard quadratic programming problem. Thus, the model and method developed exhibit very good convergence behavior in computation and provide accurate predictions of the mechanical behaviours and displacement distributions in the nanotubes. Numerical results demonstrate the validity and the efficiency of the proposed method.
Experimental study of propagation time of electromagnetic pulse through laboratory plasma
Authors: Wang Liang  , Cao Jin-Xiang  , Wang Yan  , Niu Tian-Ye  , Wang Ge  , Zhu Ying  ,   中国科学院基础等离子体物理重点实验室，中国科学技术大学近代物理系，合肥 230026
Published: December 2020

The propagation time of electromagnetic pulse(EMP) through nonmagnetic stationary laboratory Xe plasma was investigated by using network analyzer, with EMP frequency of 9—11 GHz. The research indicates that the propagation time of EMP through plasma will be less than that through the same distance in vacuum when the plasma density is in the range of 0.65—1.43×1011 cm-3，and the time delay will be a minimum at ne1.10×1011 cm-3. In this range of plasma density, the dispersion relation of electromagnetic wave in Xe plasma without magnetic field will be invalid.
SO-FDTD analysis of anisotropic magnetized plasma
Authors: Yang Hong-Wei  , Yuan Hong  , Chen Ru-Shan  , Yang Yang  ,   (1)南京理工大学通信工程系，南京 210094; (2)南京农业大学物理系，南京 210095; (3)南京农业大学物理系，南京 210095;南京理工大学通信工程系，南京 210094
Published: December 2020

A novel finite-difference time-domain (FDTD) method, called shift operator FDTD (SO-FDTD) method is developed for anisotropic magnetized dispersive media. The recursive relation between operators is used. In this paper, some expressions containing the dielectric constants of magnetized dispersive media are written as rational polynomial function. The SO-FDTD formulation for anisotropic magnetized plasma is derived. The high efficiency and effectiveness of the method are confirmed by computing the reflection and transmission through a magnetized plasma layer, with the direction of the propagation parallel to the direction of the biasing field. A comparison with frequency domain analytic results is included. The CPU time was several times shorter than that of the JEC method.
Investigation of gas puff imaging on HL-2A tokamak
Authors: Zheng Yin-Jia  , Huang Yuan  , Feng Zhen  , Shi Le  , Cui Cheng-He  , Wang Ming-Xu  , Xu Hong-Bing  ,   核工业西南物理研究院，成都 610041
Published: December 2020

GPI (gas puff imaging) is one of the important diagnostics method for investigation of the radiation in the edge region of plasma. In this paper, atomic and molecular processes during GP (gas puff) passage are analyzed. The main radiation emitting from the gas is identified as the Hα line, appearing on the plasma edge region, and the expressions of its intensity and location are given. As viewed from imaging angle, space radiation photograph of hydrogen gas during the GP was obtained experimentally. Improvements of the imaging system and GP experiment arrangement on the HL-2A tokamak are introduced. The observation results confirm the above analysis. In the beginning stage of plasma, the GP hydrogen atoms can pass through the region where the plasma column is to be set up and the bright strip region is formed. In the general GP fuelling, CCD photos are in accordance with the control signals, and other diagnostic results. The strong Hα emissions in both the HFS and LFS sides of plasma are observed.
Study on the properties of the square pattern in Air/Ar dielectric barrier discharge
Authors: Fan Wei-Li  , Dong Li-Fang  , Li Xue-Chen  , Yin Zeng-Qian  , He Ya-Feng  , Liu Shu-Hua  ,   河北大学物理科学与技术学院，保定 071002
Published: December 2020

The properties of the square pattern as a function of the relative air content is studied in Air/Ar dielectric barrier discharge system at one atmosphere pressure. The dependence of the spatial wavelength and the traveling velocity of the square pattern on the relative air content is obtained. It is found that the spatial wavelength of the square pattern is decreased with the increased relative air content at different gas gap distances. The traveling velocity of the square pattern is also closely related to the value of the relative air content, which reaches its maximum 14mm/s when the air relative component is 10%.
Structure and analytic potential energy function for the ground state of SiO2 molecule
Authors: Wu Dong-Lan  , Cheng Xin-Lu  , Yang Xiang-Dong  , Xie An-Dong  , Yu Xiao-Guang  , Deng Xiao-Hui  ,   (1)井冈山学院数理学院,吉安  343009; (2)四川大学原子与分子物理研究所,成都  610065; (3)四川大学原子与分子物理研究所,成都  610065;井冈山学院数理学院,吉安  343009
Published: December 2020

The equilibrium geometry of SiO and SiO2 molecule has been calculated on the computational levels of density functional theory (DFT). The possible electronic state and reasonable dissociation limit for the ground state of SiO and SiO2 X1A1 molecule are determined based on atomic and molecular reaction statics. And Murrell-Sorbie analytic potential energy function of SiO molecule has been derived through the least-square fitting to ab initio data. Similarly, the harmonic frequency has been calculated, and the analytic potential energy function of SiO2 molecule has been derived using many-body expansion theory.
Molecular dynamics simulation of deformation-induced crystallization mechanism in amorphous Ti3Al alloy
Authors: Wang Hai-Long  , Wang Xiu-Xi  , Wang Yu  , Liang Hai-Yi  ,   中国科学技术大学中科院材料力学行为和设计重点实验室，合肥 230026
Published: December 2020

The crystallization of Ti3Al amorphous alloy during tensile deformation was studied with molecular dynamics. The simulation results show that the crystallization of amorphous alloy is induced by the local plastic deformation. The microstructure evolution was analyzed in the tension process. It is found that the nucleation and growth are induced by the shear localization and the final crystal phase has fcc structure. It is also found that the crystallization process is accompanied by strengthening of the material. The nanocrystal grains embedded in the amorphous phase can enhance the rigidity of the sample.
Kinetics theory investigation of holographic polymer dispersed liquid crystal based on acrylate
Authors: Zheng Zhi-Gang  , Ma Ji  , Song Jing  , Liu Yong-Gang  , Hu Li-Fa  , Xuan Li  ,   (1)中国科学院长春光学精密机械与物理研究所,应用光学国家重点实验室，长春  130033; (2)中国科学院长春光学精密机械与物理研究所,应用光学国家重点实验室，长春  130033；中国科学院研究生院，北京  100049
Published: December 2020

Holographic polymer-dispersed liquid crystal (HPDLC) is formed by the diffusion of monomers and liquid crystals as a kind of switchable volume holography. The kinetics investigation of HPDLC is very important to improve the diffraction efficiency and optimize the formation conditions of HPDLC. Fourier analysis is widely adopted as analytical method of kinetics. In this paper, we make use of the one-dimensional infinite-length analytical method to develop a kinetics simulation for the real-time formation of the grating. Simultaneously， corresponding diffused kinetics equations and polymeric kinetics equations are given. Then, we find the relationship between these equations and refractive index modulation Δn, and obtain a diffraction efficiency equation which is appropriate for transmission Bragg volume grating. Finally, the ways of increasing diffraction efficiency of HPDLC is discussed. Our theoretical study should provide some useful guidance to improve the properties of HPDLC.
Influence of van der Waals force on the buckling of double-walled carbon nanotubes
Authors: Wang Lei  , Zhang Hong-Wu  , Wang Jin-Bao  ,   大连理工大学工程力学系，工业装备结构分析国家重点实验室，大连 116024
Published: December 2020

Several novel double-walled carbon nanotubes (DWCNT) composed of different internal and external nanotubes with different diameters are presented and studied by molecular dynamics simulation (MD). Initial equilibrium configurations and characteristics during free relaxation are examined. Buckling of these DWCNTs under axial compression are simulated to examine the influence of van der Waals force on mechanical properties of DWCNTs. The interaction of atoms in each wall and the van der Waals force between inner and outer walls are described by Tersoff-Brenner potential and Lennard-Jones potential respectively. Results show that new stable DWCNTs exist whose interlayer distances are not necessarily 0.34 nm. And these new DWCNTs show different mechanical behaviors as compared with the normal DWCNT.
Theoretical study of forbidden M1, M2, E2 transitions for highly charged Ni-like ions
Authors: Wan Jian-Jie  , Xie Lu-You  , Dong Chen-Zhong  , Jiang Jun  , Yan Jun  ,   (1)北京应用物理与计算数学研究所,北京  100088; (2)西北师范大学物理与电子工程学院,兰州  730070
Published: December 2020

In this paper, the energy structure and the forbidden M1,M2,E2 transition probabilities between the ground state 3s23p63d10 1S0 and the low-lying excited 3s23p63d94l, 3s23p53d104l and 3s3p63d104l (l=s,p,d,f)states have been calculated for Ni-like ions of Z=45—95, by using GRASP92 package and REOS99 code based on the relativistic multi-configuration Dirac-Fock method. By Analyzing the effects of strong configuration interaction (CI) existing in Ni-like sequence, the abnormalies of forbidden transition probabilities existing in several highly charged Ni-like ions are explained,and some general laws for the influence of CI on forbidden transition probabilities are discussed.
Molecular dynamics study of deformation mechanism of γ-TiAl intermetallics
Authors: Zhou Zong-Rong  , Wang Yu  , Xia Yuan-Ming  ,   中国科学技术大学力学和机械工程系,中国科学技术大学中科院材料力学行为和设计重点实验室,合肥 230027
Published: December 2020

The generalized planar fault (GPF) energies of various slip systems in γ-TiAl intermetallics are studied by using molecular dynamics (MD) method. The unrelaxed and relaxed GPF curves of various slip systems are compared. It was show that the γ-TiAl has fewer mobile slip systems than the fcc crystal. It is also found that the γ-TiAl intermetallics would exhibit brittle behavior at ambient temperature. The relaxed generalized stacking and twinning fault energy curves of (1/6)〈112〉{111} twinning system are obtained. By analyzing the unstable stacking fault energy γusf, the stable stacking fault energy γsf, and the unstable twinning fault energy γutf, it can be predicted that the major deformation mechanisms are twinning (1/6)〈112〉{111} and ordinary dislocation slip (1/2)〈110〉{111}, as well as superdislocation slip (1/2)〈011〉{111}.
A new model for calculating critical cooling rates of alloy systems based on viscosity calculation
Authors: Wang Zhen-Yu  , Yang Yuan-Sheng  , Tong Wen-Hui  , Li Hui-Qiang  , Hu Zhuang-Qi  ,   中国科学院金属研究所，沈阳 110016
Published: December 2020

Based on the model for calculating the critical cooling rate of bulk metallic glasses under non-isothermal condition, a new model for calculating the critical cooling rate of alloy systems based on viscosity calculation is put forward in this paper. The critical cooling rates of Zr-Ni-Al-Cu quaternary alloys were calculated and the glass forming range in Zr66.67(NixAlyCuz)33.33 quaternary alloy system is predicted. The results are in good agreement with the experimental values. The calculation results show that there is high glass forming ability in Zr66.67(NixAlyCuz)33.33 quaternary alloy system. The glass forming range is near eutectic point in which critical cooling rates are less than 100 K/s. There is not crystallization in the temperature range higher than 1000K, the fraction of crystals increases rapidly in the temperature range from 980 K to 870 K, and it is not changed in the temperature range below 870 K. In addition, the effects of Al,Cu,Ni mole fraction on the critical cooling rate are analyzed in this paper.
Analysis of adhesion process between material surfaces
Authors: Qing Tao  , Shao Tian-Min  , Wen Shi-Zhu  ,   清华大学摩擦学国家重点实验室，北京 100084
Published: December 2020

In this paper, adhesion process of two material surfaces was analyzed. Formulas for calculating jumping distance were deduced. The results of analysis showed that the jumping distance was retated to the radius of spheres, elastic modulus of the spring and the relative humidity. Effect of relative humidity was also discussed. Basing on single asperity model and the constructive equations for power-law fluid, the formulas for describing the relationship between pull-off force and the rest time were improved. Jump-to-contact force and pull-off-force were measured by a self-built adhesion apparatus.
Effect of substrate temperature on the ZnO thin films as TCO in solar cells grown by MOCVD technique
Authors: Chen Xin-Liang  , Xue Jun-Ming  , Zhang De-Kun  , Sun Jian  , Ren Hui-Zhi  , Zhao Ying  , Geng Xin-Hua  ,   南开大学光电子薄膜器件与技术研究所和天津市重点实验室；南开大学光电信息技术科学教育部重点实验室，天津 300071
Published: December 2020

Geng Xin-HuaMicrostructural,optical and electrical properties of updoped-ZnO films grown by metal organic chemical vapor deposition at different substrate temperature were investigated. XRD spectra and SEM photos indicate that the substrate temperature plays an important role on the microstructure of ZnO films. Morphological transition takes place obviously at around 175℃. The morphology of the ZnO films shows sphere-like structure at low temperature (177℃). The grain size of ZnO films grows up with the increase of substrate temperature. The high mobility (17.96 cm2/Vs) and low resistivity (3.28×10-2Ω·cm) at 177℃ have been obtained for undoped-ZnO film deposited on glass substrate. By further optimizing the structure and B-doping, ZnO film as front electrode will be applied in solar cell soon.
Electronic theory studies of aluminum matrix composite reinforced by carbon nanotube
Authors: Zhang Guo-Ying  , Zhang Hui  , Wei Dan  , He Jun-Qi  ,   沈阳师范大学物理科学与技术学院，沈阳 110034
Published: December 2020

The models of the high angle grain boundaries with different Σ(5,9,11) of pure aluminum and the interface between carbon nanotube and pure aluminum were constructed by the self-developed computer software. The electronic structures (structure energies of aluminum grain boundaries,the interfaces between carbon nanotube and pure aluminum,carbon nanotubes and fermi levels of different systems, etc.) of the carbon nanotube reinforced aluminum matrix composites were calculated with Recursion method. The calculated results show that the structure energy of the aluminum high angle grain boundary with Σ=5 is the lowest, it is t
First-principles study the optical properties of anatase TiO2 by N-doping
Authors: Peng Li-Ping  , Xu Ling  , Yin Jian-Wu  ,   (1)湖北黄冈师范学院物理科学与技术学院，黄州 438000; (2)华中科技大学物理系,武汉 430074
Published: December 2020

We have calculated the optical properties of anatase TiO2 and anatase TiO2 by N-doping by plane-wave pseudo-potential method (PWP), namely the imaginary part of dielectric function ε2(ω),the optical absorption coefficient I(ω) and the reflectivity R(ω). We have given an explanation in terms of band structures why the optical spectrum has three main peaks around 2.93 eV,3.56 eV and 3.97 eV after N-doping. Our studies of the optical spectra show that the Red-shift will happen after N-doping, and experimental phenomena also approve the result.
Synthesis and thermopower measurement of LixNayCoO2
Authors: Chen Xiao-Yang  , Xu Xiang-Fan  , Hu Rong-Xing  , Ren Zhi  , Xu Zhu-An  , Cao Guang-Han  ,   浙江大学物理系，杭州 310027
Published: December 2020

Polycrystalline samples of LixNayCoO2 with an intergrowth structure have been successfully synthesized by solid-state reaction. The measured thermopower of LixNayCoO2 at room temperature is about 60 μV/K higher than that of NaxCoO2.　Based upon the O2p characteristic for the mobile carriers, the origin of the increment in thermopower is interpreted in terms of the occupancy entropy of the O2p holes.