bluuebunny/crossref_metadata_2025 huggingface dataset:
Plasma Bragg gratings generated by the interaction of two counter-propagating laser pulses with plasmas
Authors: Luan Shi-Xia  , Zhang Qiu-Ju  , Gui Wei-Ling  ,   山东师范大学物理与电子科学学院，济南  250014
Published: December 2020

Solutions of electron and ion density gratings at the linear stage are given. Deep plasma gratings produced by the ponderomotive force of the interference of the two intersecting laser pulses are investigated. Dependence of the plasma grating on the plasma density, duration and intensity of the laser pulses are studied with 1D particle-in-cell (PIC) simulation. It is found that the density of peaks of such gratings can be 8 times the initial plasma density and can last a few picoseconds. We have found stable, long-lifetime electromagnetic solitons by use of these gratings. It is shown that the intensity for the formation of relativistic EM solitons with two crossed-propagating pulses is reduced to a great extent.
Effect of 13.56MHz low-frequency power on electrical characteristic of 60MHz radio-frequency capacitively coupled plasma
Authors: Yuan Qiang-Hua  , Xin Yu  , Huang Xiao-Jiang  , Sun Kai  , Ning Zhao-Yuan  ,   苏州大学物理科学与技术学院，薄膜材料江苏省重点实验室，苏州  215006
Published: December 2020

Dual-frequency capacitively coupled plasma (DF-CCP) driven by two frequencies of 60MHz and 13.56MHz was studied using compensated Langmuir probe technique. The change of EEPF with radial position and low-frequency input power was obtained. The experimental result shows that the input power of 13.56MHz mainly affects the population of low-energy electrons and the effect becomes greater when the gas pressure increases. The EEPF exhibits a structure of bi-energy-peak beyond the centre of discharge. The second energy peak drifts to the region of higher electron energy from the centre to the edge of electrode. The emergence of second energy peak could be attributed to the enhanced heating of middle-energy electrons. The electron density and electron temperature were calculated using EEPF. The plasma electron heating mechanism was discussed.
Simulation of a triple-gate single electron FET memory with a quantum dot floating gate and a quantum wire channel
Authors: Liu Kui  , Ding Hong-Lin  , Zhang Xian-Gao  , Yu Lin-Wei  , Huang Xin-Fan  , Chen Kun-Ji  ,   南京大学物理系，固体微结构国家实验室，南京  210093
Published: December 2020

This paper investigates a triple-gate single electron FET memory with a Si quantum dot floating gate and a Si quantum wire channel by establishing a numerical model of two-dimensional Schrdinger and Poisson equations. The electron concentration in the silicon quantum wire channel of different scales is investigated under conditions that diverse gate voltage and programming voltage are applied with a two-dimensional finite element solution. The influence of the quantum confinement effect and the electron distribution in the nano-scale channel on the structure is also investigated. Results of the simulation show that, the threshold voltage increases when the size of the channel decreases, and the voltage also increases as the number of electrons on the floating gate increases. However, a non-linear saturation tendency occurs when the number of injected electrons increases further, due to the high density of carriers in the nanoscale Si nanowire channel. Further research shows that the strong quantum confinement effect in the channel can effectively restrain the saturation tendency when the size of the channel is small enough. It's worth mentioning that the threshold voltage shift reflects the number of electrons stored on the floating gate.This effect implies a possibility of multi-level storage.
Superhardness effect of TaN/TiN and NbN/TiN nanostructure multilayers and its mechanism
Authors: Yu Li-Hua  , Dong Shi-Run  , Xu Jun-Hua  , Li Ge-Yang  ,   (1)江苏科技大学材料科学与工程学院，江苏省先进焊接技术重点实验室，镇江  212003; (2)上海交通大学金属基复合材料国家重点实验室，上海  200030
Published: December 2020

Monolithic TaN，NbN, TiN films and TaN/TiN, NbN/TiN multilayers with different modulation periods were prepared by reactive magnetic sputtering. The films were characterized by X-ray diffraction, high-resolution transmission electron microscopy and nanoindentation. Results showed that there are coherent interfaces between the layers of TaN and TiN in TaN/TiN multilayers and the layers of NbN and TiN in NbN/TiN multilayers within a modulation period. The superhardness effect happened and the maximum hardness values of the two multilayers are nearly equal. The superhardness mechanism was discussed. The lattices mismatch between NbN/TiN and TaN/TiN multilayers is similar, but the difference in modulus of NbN/TiN multilayers is larger than that of TaN/TiN multilayers. It shows that stress field induced by coherent epitaxial growth is the main reason of superhardness effect.
Study on rattling of filling atom in Sm filled-skutterudite compounds
Authors: Liu Tao-Xiang  , Tang Xin-Feng  , Li Han  , Su Xian-Li  , Zhang Qing-Jie  ,   武汉理工大学材料复合新技术国家重点实验室，武汉  430070
Published: December 2020

The single-phase polycrystalline Sm-filled skutterudites SmyFexCo4-xSb12 were investigated by Rietveld refinement and Raman scattering spectral analysis. The results of Rietveld refinement clarify that the SmyFexCo4-xSb12 compound has a filled skutterudite structure. The thermal parameter of Sm is larger than that of Sb, Fe and Co, and the Sb-Sb bond length of SmyFexCo4-xSb12 is longer than that of unfilled skutterudites. The results of Raman scattering study show a shift and broadening of the Sb4 ring breathing modes. These results indicate that Sm atoms fill the Sb-icosahedron voids of the skutterudites and rattle in them.
Effects of quenched-in vacancies on the reverse martensitic phase transformation temperature of the Cu-11.9Al-2.5Mn(wt%) shape memory alloy studied by internal friction
Authors: Wang Qing-Zhou  , Lu Dong-Mei  , Cui Chun-Xiang  , Han Fu-Sheng  ,   (1)河北工业大学材料科学与工程学院，天津  300130; (2)中国科学院固体物理研究所，合肥  230031
Published: December 2020

By internal friction technique，the behaviors of quenched-in vacancies and their influence on the reverse martensitic phase transformation (MT) temperature of the Cu-11.9Al-2.5Mn (wt%) shape memory alloy have been studied. Investigations on the specimens subjected to various cooling regimes indicate that rapid cooling rate leads to relatively high reverse MT temperature. For the water-quenched specimens，the reverse MT temperature bears a non-monotonic relationship to quenching temperature. This phenomenon may be related to the different formation energies of vacancies in ordered and disordered phases.
Real-time study of γ irradiation on Hg1-xCdxTe focal plane photodiodes
Authors: Qiao Hui  , Liao Yi  , Hu Wei-Da  , Deng Yi  , Yuan Yong-Gang  , Zhang Qin-Yao  , Li Xiang-Yang  , Gong Hai-Mei  ,   (1)中国科学院上海技术物理研究所传感技术国家重点实验室,上海  200083; (2)中国科学院上海技术物理研究所传感技术国家重点实验室,上海  200083；中国科学院研究生院，北京  100049
Published: December 2020

Real-time measurement of γ irradiation effect of Hg1-xCdx Te long-and mid-wavelength focal plane array photodiodes has been carried out. Through measuring the current-voltage characteristic during irradiation process, it has been found that mid-wavelength detectors are more radiation resistant than long-wavelength photodiodes. For long-wavelength detectors, the zero bias resistance, which is usually used to evaluate the performance of photodiodes, decreases with increased γ irradiation dosage. For mid-wavelength detectors, the zero biased resistance does not show a definite changing trend, and the irradiation mainly caused fluctuations of resistance-voltage curves with increased dosage. By numerically simulating the resistance-voltage curves of long-wavelength detectors on the basis of dark current mechanism, it was found that the lifetime ofminority carriers in the generation-recombination process was shortened and thedefects produced by irradiation increased as the dosage increased, and the affected dark current mechanism was mainly the generation-recombination current. Because the irradiated mid-wavelength detectors have much larger carrier mobility and much lower dopant density, and also a bandgap twice that of long-wavelength detectors, they showed a weaker irradiation effect. The fluctuations of the resistance-voltage curves caused by irradiation would lead to an increase on noise of the detectors.
Ca clustering and its stability in La1-xCaxMnO3(x≤1/3)
Authors: Zhang Cheng-Guo  , Zhang Xiao-Zhong  ,   先进材料教育部重点实验室，清华大学材料科学与工程系，北京  100084；北京电子显微镜中心，北京  100084
Published: December 2020

The Ca ion distribution in La1-xCaxMnO3(x≤1/3) has been studied using atomistic simulation. It is found that at low temperatures the doped Ca ions tend to be distributed in clusters with a size of about 6—19?. The stability of the clusters at high pressure and elevated temperature has also been studied, and the calculation results show that the Ca clusters are stable at 3 GPa and 120 K. This chemical phase separation may be one of the causes of the structure and electronic/magnetic inhomogeneity in La1-xCaxMnO3 found in experiments.
The adsorption of Au on Zr-doped CeO2(110) surface: A first-principle study
Authors: Wei Yan-Wei  , Yang Zong-Xian  ,   河南师范大学物理信息与工程学院,新乡  453007
Published: December 2020

The adsorption of Au on the (110) surfaces of CeO2 and Zr-doped CeO2 were studied using projector-augmented wave (PAW) method based density-functional theory (DFT) within the gradient approximation (GGA) and with the inclusion of on-site Coulomb interaction (DFT+U). It is found that, due to the doping of Zr, the adsorption energies of Au are increased and the strongest adsorption geometry is altered. The doping of Zr results in larger distortion in the structure of the substrate, and enhances the catalytic activity of the Au/CeO2(110) system and the oxidization of Au. These results may lead to a better understanding for the Au/Zr-doped CeO2 catalysts and give some clues for improving the efficiency of the three-way catalysts (TWC).
The electronic structure and thermodynamic properties of Mg2Sn from first-principles calculations
Authors: Liu Na-Na  , Song Ren-Bo  , Sun Han-Ying  , Du Da-Wei  ,   (1)北京科技大学材料科学与工程学院，北京  100083; (2)北京科技大学材料科学与工程学院，北京  100083；淄博职业学院，山东  255001; (3)淄博职业学院，山东  255001
Published: December 2020

Electronic structure, elastic constants and thermodynamic properties of Mg2Sn have been calculated by using the first-principles pseudopotential method. As shown by the calculated results, the band gap of Mg2Sn is 0.1198 eV. The linear response method is applied to determine the phonon dispersion relations and phonon density of states. The thermodynamic properties such as the constant-volume specific heat and Debye temperature are calculated. The calculated thermal conductivity is compared with the experimental data.
First principles investigation on conductivity mechanism of p-type K:ZnO
Authors: Yang Yin-Tang  , Wu Jun  , Cai Yu-Rong  , Ding Rui-Xue  , Song Jiu-Xu  , Shi Li-Chun  ,   (1)西安电子科技大学微电子学院，教育部宽禁带半导体材料与器件重点实验室，西安  710071; (2)浙江理工大学材料纺织学院,杭州  310018
Published: December 2020

The electronic structures of potassium doped ZnO have been calculated by first principles plane wave-function psuedopotential approach based on density-functional theory and local density approximation. Properties of some defects were studied in order to explicate the conductivity mechanism of p-K:ZnO, including hydrogen interstitial (Hi), oxygen vacancy (VO), zinc interstitial (Zni) and zinc vacancy (VZn). The calculated results revealed that: (1) K-doping introduced a shallow acceptor,besides increasing the system total energy simultaneously. (2) K-H:ZnO decreased the system energy and increased the system stability. (3) Although the formation of VO was more difficult than that of Zni, both of them were electronegative centers and played a role in compensating for the acceptors. (4) VZn produceda shallow acceptor approximately 0.5 eV above the maximum valence band, which was beneficial for p-type conductivity. Finally, it was proposed that the realization of p-type conductivity in K:ZnO may be due to the formation of a KZn-O-Hi-O-VZn complex.
Molecular dynamics study of the phase separation and diffusion in Lennard-Jones binary liquid
Authors: Li Mei-Li  , Zhang Di  , Sun Hong-Ning  , Fu Xing-Ye  , Yao Xiu-Wei  , Li Cong  , Duan Yong-Ping  , Yan Yuan  , Mu Hong-Chen  , Sun Min-Hua  ,   (1)哈尔滨师范大学物理与电子工程学院，哈尔滨  150025; (2)哈尔滨师范大学物理与电子工程学院，哈尔滨  150025；绥化学院物理与电子信息系，绥化  152061; (3)绥化学院物理与电子信息系，绥化  152061
Published: December 2020

Molecular dynamics (MD) simulation is performed to study the diffusion and phase separation process in binary Lennard-Jones (LJ) liquid. It is found that the growth of phase separation with temperature can be divided into two stages. The first is the fast-growth at high temperatures and the second is the steady-growth at low temperatures. Diffusion activation energy in the phase separation system is not a constant, but a function of temperature and follows the relation of E=a+bTc. The influence of the sizes of the components on the phase separation is also discussed. The results shows that the diffusivity increases when the component size decreases. This facilitates the phase separation.
First-principles study of electron field emission from the carbon nanotube with B doping and H2O adsorption
Authors: Chen Guo-Dong  , Wang Liu-Ding  , Zhang Jiao-Qiang  , Cao De-Cai  , An Bo  , Ding Fu-Cai  , Liang Jin-Kui  ,   (1)西北工业大学应用化学系，西安  710072; (2)西北工业大学应用物理系，西安  710072
Published: December 2020

The electron field emission performance of CNT doped with one Boron atom and with one adsorbed H2O molecular (BCNT+H2O) was investigated through the calculations of density functional theory (DFT) in this paper. The results indicated that there is an atomic scale region of electron congregation near the top of BCNT+H2O, and the electronic density of states (DOS) round the Fermi level is enhanced obviously. It is expected that BCNT+H2O be suitable for the field emission of electrons,judging from the calculation results of DOS, HOMO/LUMO and Mulliken charge population.
Stress-induced effects in epitaxial La0.33Pr0.34Ca0.33MnO3 films
Authors: Zhao Hua-Ying  , Yang Huan  , Ma Ji-Yun  , Fang Xu  , M. Kamran  , Dai Yao-Min  , Li Ming  , Zhao Bai-Ru  , Qiu Xiang-Gang  ,   中国科学院物理研究所超导国家重点实验室和北京凝聚态物理实验室，北京  100190
Published: December 2020

La0.33Pr0.34Ca0.33MnO3 thin films have been grown on (100) LaAlO3 and (100) SrTiO3 substrates by pulsed laser deposition, and the physical properties of those thin films have been studied through magnetic and electric transport measurements. The results show that compressive strain between the film and substrate favors the formation of the ferromagnetic metallic phase while suppressing the charge ordered insulating phase. On the contrary, tensile strain tends to enhance the ferromagnetic metallic phase while eliminating the charge ordered insulating phase. The reason could be that the strain induces change in the Mn-O bonding angle in the crystal lattice and thus modify the double exchange interaction.
Structural and optical in-plane anisotropy of m-plane GaN
Authors: Wu Chao  , Xie Zi-Li  , Zhang Rong  , Zhang Zeng  , Liu Bin  , Li Yi  , Fu De-Yi  , Xiu Xiang-Qian  , Han Ping  , Shi Yi  , Zheng You-Dou  ,   南京大学物理学系江苏省光电信息功能材料重点实验室，南京  210093
Published: December 2020

The m-plane GaN film is grown on LiAlO2 by metal organic chemical vapor deposition. The single crystal orientation of m-plane GaN is demonstrated, According to the X-ray diffraction results, and the anisotropy strain is calculated. X-ray rocking curve at different φ angle shows obvious in plane structural anisotropy. Polarized photoluminescence is employed for the investigation of optical anisotropy. Both the wavelength and the intensity for the emission peak near band edge vary with the rotation of polarization angle, and can be explained by the degeneration of the subbands in valence band under anisotropy strain.
Dependence of GaN film sheet resistance on the N2 carrier gas percentage
Authors: Xi Guang-Yi  , Hao Zhi-Biao  , Wang Lai  , Li Hong-Tao  , Jiang Yang  , Zhao Wei  , Ren Fan  , Han Yan-Jun  , Sun Chang-Zheng  , Luo Yi  ,   清华大学电子工程系清华大学信息科学与技术国家实验室/集成光电子学国家重点实验室,北京  100084
Published: December 2020

In this paper, GaN films are grown by metal organic vapor phase epitaxy. Different N2 carrier gas percentages were used in the high-temperature growth process of the bulk GaN, and the dependence of sheet resistance on N2 carrier gas percentage is studied. It is found that the sheet resistance of the GaN film increases dramatically with N2 carrier gas percentage. When N2 carrier gas percentage is 50%, the sheet resistance of the GaN film is 1.1×108Ω/sq, and the surface root-mean-square roughness is as small as 0.233 nm. Secondary ion mass spectroscopy measurements reveal that the concentration of carbon and oxygen impurities is almost the same in the samples with different N2 carrier gas percentage. The density of edge-dislocation-related defects increases with N2 carrier gas percentage, while the density of screw-dislocation-related defects shows no obvious difference for all the samples. Our results indicate that the increase of the sheet resistance of GaN film is mainly due to the increase of edge threading dislocations, which act as acceptor centers in the GaN material.
Influence of pit defects on AlGaN surface and dislocation defects in GaN buffer layer on current collapse of AlGaN/GaN HEMTs
Authors: Xi Guang-Yi  , Ren Fan  , Hao Zhi-Biao  , Wang Lai  , Li Hong-Tao  , Jiang Yang  , Zhao Wei  , Han Yan-Jun  , Luo Yi  ,   清华大学电子工程系集成光电子学国家重点实验室/清华大学信息科学与技术国家实验室,北京  100084
Published: December 2020

The influence of pit defects on AlGaN surface and dislocation defects in GaN buffer layer on the current collapse of MOVPE-grown AlGaN/GaN high electron mobility transistors (HEMTs) is studied in this paper. Pulsed gate voltage measurements show that the surface pit defects result in gate lag current collapse and increased of source/drain resistance. And the more pit defects exist, the more obvious current collapse and increased source/drain resistance are observed. Pulsed drain voltage measurements show that the drain lag current collapse, which is almost unaffected by the surface pit defects, can be associated with the dislocation defects in GaN buffer layer. Our experimental results indicate that pit defects on AlGaN surface and dislocation defects in GaN buffer layer can be one of the origins of gate lag and drain lag current collapse, respectively.
Oscillations of Josephson-vortex flow resistance in high-Tc superconductors
Authors: You Yu-Xin  , Zhao Zhi-Gang  , Wang Jin  , Liu Mei  ,   东南大学物理系,南京  210096
Published: December 2020

Using the coupled sine-Gordon equations，we investigate the motion of Josephson vortex in high-Tc superconductors. It is found that the oscillation behavior in the average voltage and resistance of Josephson vortex flow appear with the increasing of magnetic field in a fixed bias current. The period of the oscillation corresponds to the field, which has the magnitude of adding one Josephson vortex quantum per one intrinsic Josephson junction.
Preparation, structure and ferromagnetic properties of perovskite BaFeO3 nanocrystals
Authors: Liu Yan-Yan  , Liu Fa-Min  , Shi Xia  , Ding Peng  , Zhou Chuan-Cang  ,   北京航空航天大学理学院物理系，北京  100191
Published: December 2020

The Perovskite BaFeO3 nano-powder has been synthesized by sol-gel method. The micro-structure and morphology of BaFeO3 nano-powder have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). The results showed that the samples annealed at 800 ℃ formed the perovskite-type BaFeO3 with grain size of about 20 nm and the (110) and (100) spacings of about 0.280 nm and 0.401 nm, respectively. The room temperature magnetic properties of samples have been measured on vibrating sample magnetometer (VSM). It is shown that the BaFeO3 nano-powder has a complete hysteresis loop, which means that BaFeO3 powder possess significant weak ferromagnetism at room temperature, and this property changes obviously with the annealing temperature. Ferromagnetism of perovskite BaFeO3 nano-powder mainly originates from oxygen vacancy among Fe3+-O-Fe4+.
The energy transfer in phosphorescent dye PtOEP doped organic molecule Alq
Authors: Wu Chun-Hong  , Liu Peng-Yi  , Hou Lin-Tao  , Li Yan-Wu  ,   暨南大学物理学系，广州  510632
Published: December 2020

The energy transfer process of phosphorescent dye PtOEP (2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine platinum(II) doped organic molecule Alq (tris(8- hydroxyquinoline) aluminum) thin films were studied by steady-state spectrum and time-resolved spectrum. The energy transfer efficiency and critical radius of the doped thin films were estimated from the overlap integral between the absorption spectra of PtOEP and the fluorescent spectra of Alq based on Frster theory. The experimental results from steady fluorescent spectra were approximately consistent with the estimation, which indicates that Frster energy transfer mechanism is operative in dye doped organic thin films. The experimental results from time-resolved fluorescent spectroscopy show that the fluorescent lifetime of Alq in the doped thin films decreases gradually with the doping concentration, indicating that there is an efficient energy transfer from Alq to PtOEP in the doped thin films.
Influence of oxygen pressure on the structure and photoluminescence of β-Ga2O3 nano-material prepared by thermal evaporation
Authors: Ma Hai-Lin  , Su Qing  , Lan Wei  , Liu Xue-Qin  ,   兰州大学物理科学与技术学院，兰州  730000
Published: December 2020

We have prepared the gallium oxide (β-Ga2O3) nanomaterials from gallium and oxygen by thermal evaporation in the argon atmosphere and researched their photoluminescence (PL). X-ray diffraction (XRD) revealed that the synthesized products are monoclinic gallium oxide, and its morphology as observed by the scanning electron microscope (SEM) revealed that Ga2O3 nanobelts with breadth less than 100nm and length of several micrometers are synthesized under low oxygen pressure, while nanoparticles are synthesized under high oxygen pressure. Room-temperature photoluminescence under excitation of 325 nm shows that the β-Ga2O3 nanostructures have stable emission at 516 nm, which may be related to the defects such as the oxygen vacancies and the gallium-oxygen vacancy pairs.
The blue luminescence of cerium doped aluminum oxide thin film
Authors: Liao Guo-Jin  , Yan Shao-Feng  , Ba De-Chun  ,   (1)东北大学机械工程与自动化学院，沈阳  110004; (2)辽宁工业大学机械工程与自动化学院，锦州  121001
Published: December 2020

Amorphous aluminum oxide thin films doped with cerium have been deposited by middle frequency reactive magnetron sputtering. There exist Ce3+ ions in the Al2O3:Ce thin films as shown by XPS measurement. The photoluminescence emission from these films show peaks around 374 nm which are associated with 5d to 4f transitions of Ce3+ ions. The intensity of these peaks is strongly dependent on the amount of cerium incorporated in the films. The presence of cerium as well as the stoichiometry of these films have been determined by energy dispersive X-ray spectroscopy (EDS) measurements. It is proposed that the light emission observed is generated by luminescence centers associated with trivalent ionic cerium impurities. The crystalline structure of the sample was analysed by X-ray diffraction (XRD). Auger electron spectroscopy has been used to estimate the stoichiometry of the films. This luminescence feature is advantageous for display techniques which require a purer blue emission.
Investigation of microcrystalline silicon germanium prepared by hydrogen and helium gas mixture diluted VHFPA-RTCVD
Authors: Zhang Li-Ping  , Zhang Jian-Jun  , Zhang Xin  , Shang Ze-Ren  , Hu Zeng-Xin  , Zhang Ya-Ping  , Geng Xin-Hua  , Zhao Ying  ,   南开大学光电子薄膜器件与技术研究所，天津市光电子薄膜器件与技术重点实验室，天津  300071
Published: December 2020

H2 and He gas mixture diluted very high frequency plasma assisted reactive thermal chemical vapor deposition (VHFPA-RTCVD) is used to prepare μc-SiGe:H thin films, and the optical emission spectrum is used to in situ monitor the reacting plasma during the growing process. It is observed that H2 and He gas mixture dilution is effective in increasing the number of Hα* and reducing the temperature of electrons in the plasma. X-ray diffraction (XRD) and photo- and dark-conductivity measurement show that by optimizing the fractions of H2 and He in the mixture the defect states are reduced, which prompted the growth of and improved the structure, and the optical-electronical properties of the film are enhanced.
A silo of which the pressure on the bottom of granular matter does not go to saturation
Authors: Jiang Yi-Min  , Zheng He-Peng  ,   (1)中南大学物理科学与技术学院，长沙  410083; (2)中南大学物理科学与技术学院，长沙  410083；中南大学粉末冶金国家重点实验室，长沙  410083
Published: December 2020

As height increases a vertical granular column in a bin can transfer its weight the side wall gradually, then pressure at bottom ceases to increase with the height and reaches to saturation. However it is notable that not every granular column will stay in this stress status with saturation, known as the silo-effect. For example, when mechanical environments of the side wall are modified such that it is unable to take on the weight of granular matter, the bottom pressure will evidently increase linearly with the height. This work analyzes using the assumptions given by Janssen the behavior of this rather unusual granular column, which is in static mechanical equilibrium but does not have a stress saturation as in conventional silos.
Simulation of polymer-fullerene bulk heterojunction solar cell
Authors: Xing Hong-Wei  , Peng Ying-Quan  , Yang Qing-Sen  , Ma Chao-Zhu  , Wang Run-Sheng  , Li Xun-Shuan  ,   兰州大学物理科学与技术学院,兰州  730000
Published: December 2020

A numerical model of organic bulk heterojunction solar cell based on Onsager's theory of geminate charge recombination and related theory of inorganic semiconductors is described. the correctness of the model is verified by experimental data. On the basis of this model, we analyzed the influence of effective voltage and operating temperature on the properties of organic solar cells and the factors that affect the photocurrent efficiency of the device.
An approach to research the topology of Chinese temperature sequence based on complex network
Authors: Zhou Lei  , Gong Zhi-Qiang  , Zhi Rong  , Feng Guo-Lin  ,   (1)扬州大学物理科学与技术学院，扬州  225002；国家气候中心，中国气象局气候研究开放实验室，北京  100081; (2)扬州大学物理科学与技术学院，扬州  225002；中国科学院大气物理研究所东亚区域气候-环境重点实验室，北京  100029; (3)扬州大学物理科学与技术学院，扬州  225002；中国科学院大气物理研究所东亚区域气候-环境重点实验室，北京  100029；国家气候中心，中国气象局气候研究开放实验室，北京  100081
Published: December 2020

To analyze the dynamics of the temperature data, using homogenous partition of coarse graining process, the series of Chinese daily main temperature from 1961 to 2002 is transformed into symbolic sequences consisting of 5 characters {R,r,e,d,D}. The vertices of the temperature fluctuation network is 125 3-symbol strings (i.e., 125 fluctuation patterns in durations of 4 days), linked in the network's topology by time sequence. It contains Integrated information about interconnections and interactions between fluctuation patterns of temperature in network topology. Random fluctuant network and chaos fluctuant network by using random sequence and chaos sequence of Lorenz system were built. We calculated the dynamical statistics of the degrees and the distribution of degrees, clustering coefficient and the shortest path length, and compared the difference of these three sequences from the view point of network. The result is that. The main vertices of temperature fluctuant network generally contain the 3 characters R, r and e, and corresponding the background of global warming, the feature of temperature fluctuation is mainly ascending. On all accounts, the temperature fluctuant network is similar with chaos network in its dynamical statistics, but is markedly different from random network, which reflects the complexity of temperature fluctuation. And besides, some vertices in temperature fluctuant network have high betweenness centrality (BC), 4% of vertices bear 71.9% of betweenness centrality of networks, these vertices of importance in topological statistics are helpful to understanding the inherent law and information transmission. The vertices' BC in chaos network is similar with that of the temperature network, but vertices in random network almost have identical betweenness centrality. As a result, the patterns of temperature fluctuation corresponding to the process of weather change have similar property with chaos rather than the random fluctuation process.
Synchronization of the applause with leaders
Authors: Sun Yong-Zheng  , Ruan Jiong  , Li Wang
Published: December 2020

Synchronization of the applause with leaders is investigated. The cases of the presence or absence of the effect of the applause transmission time delay on the part of the spectators are considered rcspectively. Sufficient conditions for the applause synchronization are presented for each case. The obtained theoretical results not only manifest the observation that rhythmic applauses are more frequently heard in a theater with high attendance rate, but also show a surprising conclusion that one leader is enough to make all spectators clap with the same frequency in a very large theater. Furthermore, numerical examples are provided to illustrate the validity of the theoretical results.
Study on the potential energy function for the ground state （X1Σ+）of SiO molecule by density functional theory
Authors: Xu Guo-Liang  , Lü Wen-Jing  , Xiao Xiao-Hong  , Zhang Xian-Zhou  , Liu Yu-Fang  , Zhu Zun-Lue  , Sun Jin-Feng
Published: December 2020

The structural optimization for the ground state (X1Σ+) of SiO molecule has been calculated using density functional theory B3P86 method with the basis sets STO-3G, D95**, 6-311G, 6-311++G, 6-311++G** and cc-PVTZ. The conclusion is draun by comparison that the basis set cc-PVTZ is the most suitable for the structural optimization calculation of the ground state (X1Σ+) of SiO molecule. The analytical potential energy curve for the ground state (X1Σ+) of SiO molecule is scanned using B3P86/cc-PVTZ method, and then fitted to the Murrell-Sorbie function using least squares. At last the spectroscopy constants (Be，αe，ωe and ωeχe) related to the analytical potential energy function are calculated and compared with the experimental data.
The stimulated Raman scattering and the four wave mixing in the generation of sub-10 fs pulses
Authors: Deng Li  , Sun Zhen-Rong  , Lin Wei-Zhu  , Wen Jin-Hui
Published: December 2020

A self-built self-mode-locked Ti:sapphire laser is operated at the upper edge of the stable region. Tow double-prism systems are used to compensate for thesecond-order dispersion in and out of the laser cavity. Broad band laser pulses with bandwidth of 664—840nm have been generated, and their mode changes from the basic mode to the ring structure. The interesting experimental phenomenon is due to the stimulated Raman scattering and the four wave mixing, which provides the necessary condition to generate the sub-10fs laser pulses.
Up-conversion luminescence in Er3+/Yb3+-codoped Gd3Sc2Ga3O12 laser crystals
Authors: Luo Jian-Qiao  , Sun Dun-Lu  , Zhang Qing-Li  , Liu Wen-Peng  , Gu Chang-Jiang  , Wu Lu-Sheng  , Yin Shao-Tang
Published: December 2020

Er3+/Yb3+:Gd3Sc2Ga3O12 and Er3+:Gd3Sc2Ga3O12 crystals have been grown by Czochralski method. The absorption spectra from 320 to 1700nm and the up-conversion fluorescence spectra from 500 to 750nm of them were investigated at room temperature, respectively. The possible up-conversion luminescence mechanisms in Er3+/Yb3+-codoped crystals and their influences on the 2.8μm laser emission were discussed. Experimental results show that the absorption of Er3+:Gd3Sc2Ga3O12 around 966nm and its bandwidth are remarkably increased by Yb3+ sensitizing. Under 940nm excitation, the up-conversion luminescence intensity of Er3+/Yb3+:Gd3Sc2Ga3O12 is much stronger than that of Er3+:Gd3Sc2Ga3O12. It demonstrates that there exist effective energy transfer processes between Yb3+ and Er3+, and the dominant mechanism of up-conversion may be the energy transfer processes of Yb3+-Er3+ and Er3+-Er3+.
Experimental diagnosis of plasma jets by using an X-ray laser
Authors: Wang Chen  , Fang Zhi-Heng  , Sun Jin-Ren  , Wang Wei  , Xiong Jun  , Ye Jun-Jian  , Fu Si-Zu  , Gu Yuan  , Wang Shi-Ji  , Zhen Wu-Di  , Ye Wen-Hua  , Qiao Xiu-Mei  , Zhang Guo-Ping
Published: December 2020

The supersonic jets and the interaction of strong shock waves are ubiquitous features of the nonlinear hydrodynamics of inertial-confinement fusion, astrophysics, and related fields of high energy-density science, so very important value have their studies in laboratory. A laboratories experimental study on jets is reported. The plasma jets were created by an ns laser pulse irradiating a special circular hole target, and the shadow of jets were recorded by using an X-ray laser probe with wavelength of 13.9nm. Legible shadow images of plasma jets were obtained. The experimental results and theoretical simulation were in qualitative agreement.
Approximate solution to a nonlinear oscillation of global climate model
Authors: Mo Jia-Qi  , Lin Yi-Hua  , Lin Wan-Tao  ,   (1)安徽师范大学数学系,芜湖  241000; (2)中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室,北京  100029
Published: December 2020

A type of nonlinear model of the global climate is considered. By using the perturbation theory and method, solution to the asymptotic expansions of some related problems are constructed. The asymptotic expansions of the solution to the original problem have a higher degree of approximation. The perturbed asymptotic method is an analytic method, and the obtained solution can be analytically operated sequentially.
Three-dimensional electromagnetic particle-in-cell simulation by parallel computing
Authors: Liao Chen  , Liu Da-Gang  , Liu Sheng-Gang  ,   电子科技大学物理电子学院，成都  610054
Published: December 2020

Three-dimensional electromagnetic particle-in-cell （PIC） simulation is based on FDTD （finite-differential time-domain） and PIC methods. Based on the characteristics of these methods, the parallel algorithm was designed, which divided the whole simulation domain into a number of subdomains, and every computing process simulated a subdomain and transferred the boundary information. Then the influencing factors of speedup were analyzed. Finally, the parallel algorithm was implemented in CHIPIC3D software and the parallel version of CHIPIC3D was used to simulate a kind of magnetically insulated transmission line oscillator and the relative klystron amplifier. The results show that the parallel algorithm is correct and the speedup is increased.
An equivalent mass source method for internal waves generated by a body moving in a stratified fluid of finite depth
Authors: You Yun-Xiang  , Zhao Xian-Qi  , Chen Ke  , Wei Gang  ,   (1)解放军理工大学理学院，南京  211101; (2)上海交通大学海洋工程国家重点实验室，上海  200240
Published: December 2020

An equivalent mass source is modeled as excited sources of internal waves generated by the displacement of fluid and the wake of vortex shedding or turbulence due to the body moving in a stratified fluid, a mathematical model for the vertical displacement of internal waves generated by such an equivalent mass source is presented by use of both the associated eigenvalue problem and the Fourier transform method, and the method for estimating the speed, length and diameter of the equivalent mass source is proposed. Calculations based on the proposed method are performed for the generation of internal waves by a towed sphere in a stratified fluid, and the numerical results are in good agreement with the available experimental results of Robey in the kinematic wave patterns and the maximum peak-to-peak amplitude of the internal waves. Such a method may have potentially important applications.
A unified boundary integral equation for sound radiation and scattering from the open/closed thin bodies
Authors: Mao Yi-Jun  , Qi Da-Tong  ,   西安交通大学能源与动力工程学院,西安  710049
Published: December 2020

A unified boundary integral equation is proposed to solve the sound radiation and scattering from the open/closed thin-bodies with arbitrary acoustic impedance in two- and three-dimensional domain. The proposed integral equation has the same influence matrix for both acoustic radiation and scattering problems and can synchronously solve the sound radiation and scattering from non-compact thin-body with arbitrary acoustic impedance condition, which can be applied to predict the noise of turbomachinery, pipe, and the muffler performance. In further work, the effects of moving surface and moving medium on sound radiation and scattering should be considered.
Electromagnetic field boundary conditions on moving interfaces in high frequency case
Authors: Tan Kang-Bo  , Liang Chang-Hong  ,   西安电子科技大学天线与微波国家重点实验室，西安  710071
Published: December 2020

The electromagnetic properties of the moving media interface in a high frequency range is analysed and the dependence of generalized refraction on frequency is obtained based on special relativity.
Controll of spatiotemporal chaos by applying feedback method based on the flocking algorithms
Authors: Zhou Jian-Huai  , Deng Min-Yi  , Tang Guo-Ning  , Kong Ling-Jiang  , Liu Mu-Ren  ,   广西师范大学物理科学与技术学院，桂林  541004
Published: December 2020

Spatiotemporal chaos control in one-dimensional complex Ginzburg-Landau equation was described. We proposed a method of coupled feedback based on the flocking algorithms. By using the homogeneous-periodic solutions and the traveling wave solutions as our target, we showed numerically that the spatiotemporal chaos can be controlled to a regular state if appropriate control strength was chosen. The physical mechanism was analyzed based on the correlation function.
Analysis of medium-frequency oscillation in the Boost power factor correction converter with average current mode control
Authors: Wang Fa-Qiang  , Zhang Hao  , Ma Xi-Kui  , Li Xiu-Ming  ,   西安交通大学电气工程学院，电力设备电气绝缘国家重点实验室，西安  710049
Published: December 2020

On the assumption that the input voltage can be replaced by its RMS value and the frequencies of the inductor current and the output voltage are much lower than the switching frequency of the converter, the small-signal model of Boost PFC converter is constructed and the medium-frequency oscillation in Boost PFC converter is studied. The underlying mechanism of this nonlinear phenomenon is analyzed and the stability conditions are also given. These obtained results indicate that this type of nonlinear phenomenon is different from the fast- and slow-scale instabilities, and the main characteristic of this type of nonlinear phenomena is that its oscillation frequency lies between the line frequency and the switching frequency. Finally, an experimental circuit is designed, and its experimental results agree very well with the simulation results.
A slide-type multianvil ultrahigh pressure apparatus and calibrations of its pressure and temperature
Authors: Lü Shi-Jie  , Luo Jian-Tai  , Su Lei  , Hu Yun  , Yuan Chao-Sheng  , Hong Shi-Ming  ,   西南交通大学高温高压物理研究所，成都  610031
Published: December 2020

A slide-type ultrahigh pressure apparatus with 6/8 anvils is described. The three-supporting pillars of the main framework and the slide-type multi-anvils have conformable mechanical symmetry. Under the loading uniaxial pressure, the first-stage anvils can be self-corrected and run with excellent synchronicity and reproducibility. In the present experiments, the edge length of pyrophyllite octahedron is 125 mm and the truncation edge length of tungsten carbide anvil is 8 mm. The cell pressure was calibrated at room temperature by means of the known pressure-induced phase transitions of Bi and ZnTe at 255, 77, 96 and 120 GPa. The cell temperature under 10 GPa was measured up to 1560 ℃ by WRe3-WRe25 thermocouple. The temperature calibration was reconfirmed and extended to the higher range by observation of diamond formation on the interface between graphite heater and steel plug, and by comparison of the variational details of recorded data and the Fe—C phase diagram, and then the axial temperature gradient was estimated to be about 21 ℃/mm.
GaN/AlGaN dual-band infrared detection and photon frequency upconversion
Authors: Zhou Li-Gang  , Shen Wen-Zhong  ,   上海交通大学物理系，凝聚态光谱与光电子物理实验室，上海  200240
Published: December 2020

A detailed investigation on dual-band （mid- and far-） infrared detection and photon frequency upconversion in GaN/AlGaN heterojunction structures is carried out. We deduce the Al composition in intrinsic AlGaN barrier layer through photoluminescence spectroscopy, and evaluate the conduction bandgap interfacial workfunction in GaN/AlGaN with different Al compositions. Based on the mid- and far-infrared responsivity simulation of single-period GaN/AlGaN heterojunction detector, we investigate the mid- and far-infrared photon frequency upconversion efficiencies of multi-period GaN/AlGaN heterojunction detectors integrated with GaN/AlGaN violet light emitting diodes in relation to the GaN emitter layer thickness, intrinsic AlGaN barrier layer thickness, violet photon extraction efficiency, internal quantum efficiency, spatial frequency, and GaN emitter doping concentration. The results show that GaN-based infrared upconversion devices have high upconversion efficiency and good optoelectronic application prospect.
Theoretical calculation of Lα X-ray production cross sections of Ga, As, Pt, W and Au atoms by electron impact
Authors: He Biao  , Yi You-Gen  , Jiang Shao-En  , Tang Yong-Jian  , Zheng Zhi-Jian  ,   (1)中国工程物理研究院高温高密度等离子体物理国家重点实验室,绵阳  621900; (2)中南大学物理科学与技术学院,长沙  410083
Published: December 2020

The Lα x-ray production cross sections of Ga, As, Pt, W and Au by electron impact are calculated using a modified version of the BELL formula by incorporating both ionic and relativistic corrections in it. The proposed modified Bell model with a single set of parameters can provide an excellent data in the reduced energy range 1≤E/Inl≤106（E and Inl are, respectively, the incident energy and ionization energy） with performance level at least as good as any of the existing methods and models. Experimental data are compared with the present results in cases of with and without the relativistic correction factor GR and the ionic correction factor Fion, with calculated cross sections obtained from the distorted wave Born approximation and with other experimental data available in the literature. The calculated results can be used to simulate the hot-electron energy spectrum and laser plasma yields and accordingly can provide accurate parameters for electron devices.
Cobalt-like-Xe-induced infrared light and x-ray emission at Ni surface
Authors: Zhang Xiao-An  , Yang Zhi-Hu  , Wang Dang-Chao  , Mei Ce-Xiang  , Niu Chao-Ying  , Wang Wei  , Dai Bin  , Xiao Guo-Qing  ,   (1)咸阳师范学院物理系,咸阳  712000; (2)咸阳师范学院物理系,咸阳  712000；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
Published: December 2020

The highly charged ions129Xe27+ impacting on Ni surface are neutralized by resonant capturing of electrons of metallic conduction band and release of potential energies. The multiply excited Xe atoms are formed and the outer-shell electrons are de-excited by emitting infrared photons. In the process, within femtoseconds, the projectile total energies are deposited on the target surface （on the nanometers scale）, which excites and ionizes the target atoms. The characteristic transitions between complex configurations of atoms and ions occur, especially the characteristic forbidden transition （M1 and E2） of NiⅠand NiⅡ, and the X-ray emission. The increasing of X-ray yield per ion with kinetic energies of projectile was found.
Vibrational excitation integrated cross sections of e-H2 scattering
Authors: Wang Bin  , Feng Hao  , Sun Wei-Guo  , Zeng Yang-Yang  , Dai Wei  ,   (1)四川大学物理科学与技术学院，成都  610065; (2)四川大学原子分子物理研究所，成都  610065
Published: December 2020

The vibrational excitation integrated cross sections （ICSs） of the low-energy electron-H2 scattering are studied using the vibrational close-coupling （VCC） method. 18 Morse vibrational states, 5 partial waves and 4 molecular symmetries are used to converge the vibrational excitation ICSs. It is shown that the properties of the vibrational excitation scattering potentials and the accuracy of the vibrational excitation ICSs may be affected by the quality of the vibrational wavefunctions and the accuracy of the vibrational energies. The converged vibrational excitation （ν0=0→ν=0，1，2，3） ICSs agree well with the known experimental results.
The two-dimensional periodic structure in a bifrequency magnetically insulated transmission line oscillator
Authors: Wang Dong  , Chen Dai-Bing  , Qin Fen  , Fan Zhi-Kai  ,   中国工程物理研究院应用电子学研究所，绵阳  621900
Published: December 2020

The eigen function of a bifrequency magnetically insulated transmission line oscillator （BFMILO） is deduced, and the dispersion characteristics and the field distribution are analyzed in detail. By dividing a traditional symmetrical coaxial disk loaded slow wave structures （SWS） into two different azimuthal partitions, the SWS of BFMILO becomes a two-dimensional SWS. In this structure, different electromagnetic modes are distributed in different azimuthal partitions, so that two different electromagnetic modes, which are competition modes in a traditional MILO, can interact with electrons separately and stably. This special SWS is the key point in designing a BFMILO. The proposed method can also be used in analyzing a mlti-frequency MILO.
Steady transmission characteristics of intense electron beams in one-dimensional drift spaces
Authors: Zhang Yong-Peng  , Liu Guo-Zhi  , Shao Hao  , Yang Zhan-Feng  , Song Zhi-Min  , Lin Yu-Zheng  ,   (1)清华大学工程物理系，高能辐射成像国防重点学科实验室，北京  100084; (2)清华大学工程物理系，高能辐射成像国防重点学科实验室，北京  100084；西北核技术研究所，西安  710024; (3)西北核技术研究所，西安  710024
Published: December 2020

For one-dimensional drift spaces with parallel and cylindrical structures, space-charge-limited currents are calculated, and the steady transmission of intense electron beams exceeding the currents with virtual cathodes are studied theoretically. The transmission characteristics, such as the position of virtual cathode, the transmission rate of electrons at virtual cathode, and the transit-time of electrons in the spaces, are given analytically.
Influence of the virtual photon field on the squeezing properties of atom laser
Authors: Zhao Jian-Gang  , Sun Chang-Yong  , Meng Xiang-Guo  , Su Jie  ,   聊城大学物理科学与信息工程学院,聊城  252059
Published: December 2020

The squeezing properties of atom laser are investigated with and without rotating-wave approximation by means of quantum theory in the system of optical field interacting with Bose-Einstein condensate of two-level atoms. The influences of the atomic eigenfrequency, the interaction intensity between optical field and atoms，the initial squeezing factor of optical field and the virtual photon field on the squeezing properties are discussed. The results show that two quadrature components of atom laser can be squeezed periodically. The quantum Rabi frequency and the collapse and revival frequency of atom laser fluctuation depend on the atomic eigenfrequency and the interaction intensity between optical field and atoms respectively. When the initial squeezing factor of optical field increases and the virtual photon field is considered, the degree of squeezing of the atom laser also increases.