bluuebunny/crossref_metadata_2025 huggingface dataset:
In-plane and out-of-plane orientation influence on thermal stabilities of RBa2Cu3Oz thin film
Authors: Xu Xue-Ｑin  , Tang Chen-Yi  , Wang Xuan  , Cheng Ling  , Yao Xin  ,   上海交通大学物理系,上海  200240
Published: December 2020

Appling high temperature optical microscopy （HTOM）, the in-situ observations on the melting process of RBa2Cu3Oz（RBCO） oxide thin films were carried out. Combined the X-ray diffraction （XRD） pole figures with the scanning electron microscope （SEM）, the microstructure of RBCO thin films with different in-plane and out-of-plane orientations were studied. The relationship between the thermal stability of RBCO thin film and its microstructure was investigated. The conclusions of semi-coherent interface energy theory is in good agreement with the experimental results from HTOM, SEM and XRD. It is evident that the thermal stability of 0° in-plane YBCO grain surpasses the 45° one in the air. Additionally, it was found that a very small volume percentage of a-axis grain has an obvious influence on the decomposition behavior and thermal stability of SmBCO film.
Effect of thermal stresses on fused silica surface on the laser induced damage
Authors: Liu Hong-Jie  , Huang Jin  , Wang Feng-Rui  , Zhou Xin-Da  , Jiang Xiao-Dong  , Wu Wei-Dong  ,   中国工程物理研究院激光聚变研究中心,绵阳  621900
Published: December 2020

To study the effect of the thermal stresses on the optics, experiment is performed to measure the damage threshold of the two fused silica samples with one annealed to eliminate thermal stresses while the other not. The measurement includes the effects of the thermal stresses on the initial damage threshold of the fused silica, the damage growth threshold, and the damage growth laws. The results show that the damage threshold decreases as the thermal stresses increase, and the damage induced by the laser is accelerated by the thermal stresses. For the same laser intensity, the damage growth factor is higher for the area with higher thermal stresses, but the damage growth still obeys the exponential increase rule and no obvious effect of the thermal stresses is found on the damage growth threshold. The study here will determine to some extent whether the technology of the CO2 laser pretreatment can be applied to the large-aperture optics or not.
Study on a new chaotic system with analysis and circuit experiment
Authors: Xu Zhe  , Liu Chong-Xin  , Yang Tao  ,   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

In this paper，we study a new chaotic system which is totally different from the Lorenz chaotic system，Chen chaotic system and Liu chaotic system. Firstly，the basic dynamical behaviors of new chaotic system are studied. The influence of system parameter on the chaotic system is discussed through Lyapunov exponent spectrum and bifurcation diagram. The results between simulation and experiment are in good agreement，thereby proving the veracity of analysis.
Electronic structure and optical properties of transition metal doped titanate nanotubes
Authors: Le Ling-Cong  , Ma Xin-Guo  , Tang Hao  , Wang Yang  , Li Xiang  , Jiang Jian-Jun  ,   华中科技大学电子科学与技术系,武汉  430074
Published: December 2020

The electronic structure and optical properties of transition metals （TM）-doped （Fe, Co or Ru） titanate nanotubes （TNTs） have been investigated by using the plane-wave ultrasoft pseudopotential method. TM atom intercalation into the interlayer region of the layered TNTs structure has great influence on the geometry of the original structure and the formation energy of Co-doping or Ru-doping is lower after geometry optimizations. Doped atoms bond with the surrounding O atoms to form a kind of solid solution. The results show that, Fe,Co or Ru intercalation reduces the band gap of TNTs and introduces new energy levels in the band gap, extending the absorption edge of the doped TNTs well into the visible region, which is due to the appearance of the b1g（dx2－y2） and a1g（dz2） states; partial impurity bands are in semi-filled states, which act as the capture centers of holes to reduce the recombination of electrons and holes; the valence bands of the doped TNTs move towards low energy, making the holes more oxidative. Finally, the absorption spectrum of the doped TNTs shows that Ru-doped TNTs has a stronger absorptive capacity in the visible region.
Optical property of Bi3+∶Eu3+-codoped borosilicate glass with Eu3+ ions as probe
Authors: Xu Wei  , Li Cheng-Ren  , Chen Bao-Jiu  , Feng Zhi-Qing  ,   (1)大连海事大学物理系，大连  116026; (2)大连民族学院理学院，大连  116600; (3)辽宁师范大学物理与电子技术学院，大连  116029
Published: December 2020

A series of samples about Eu3+ doped, Bi3+∶Eu3+-codoped borosilicate glasses have been prepared by high-temperature sintering. The excitation spectra, emission spectra and the phonon sideband spectra of the samples were measured. The influence on the luminescence of Eu3+ ions was discussed with Eu3+ ions as probe when Bi3+ions were doped. The results show that the electron-phonon coupling coefficient calculated in this study is smaller than those of borate-lead glasses and others reported before, but the probability of non-radiative transition of Eu3+ ions is increased by the doping of Bi3+ ions. The Bi3+ ions can sensitize Eu3+ ions, and when Bi3+ ions are doped, the covalent property becomes bigger with the symmetry becoming smaller ，which enhances the luminescence intensity of Eu3+ ions on the whole. Therefore, in the borosilicate glasses, the increase of luminescence intensity about Eu3+ ions is the result of the combined action between the above factors，not simply because of the energy transition from Bi3+ ions to Eu3+ ions.
Performance optimization of p-i-n type microcrystalline silicon thin films solar cells deposited in single chamber
Authors: Zhang Xiao-Dan  , Sun Fu-He  , Xu Sheng-Zhi  , Wang Guang-Hong  , Wei Chang-Chun  , Sun Jian  , Hou Guo-Fu  , Geng Xin-Hua  , Xiong Shao-Zhen  , Zhao Ying  ,   南开大学光电子薄膜器件与技术研究所，光电子薄膜器件与技术天津市重点实验室，光电信息技术科学教育部重点实验室，天津  300071
Published: December 2020

In-situ hydrogen plasma treating technique and burial method using microcrystalline silicon layer were used respectively to reduce the boron contamination in intrinsic layer for the p-i-n type microcrystalline silicon thin film solar cells deposited in single chamber. The measurement results of J-V relation and the quantum efficiency of solar cells proved that both of them improve the short circuit current density of solar cells to some extent. However, each method showed different effects on the other characteristic parameters of solar cells. By optimizing the hydrogen treating time and light trapping structure, single junction microcrystalline silicon thin film solar cell with 6.39% conversion efficiency has been fabricated in single chamber.
Latest progress of Monte Carlo simulation of light transmission in tissues
Authors: Deng Yong  , Meglinski Igor  ,   (1)Cranfield Health,Cranfield University,Cranfield,MK43 0AL,UK; (2)华中科技大学光电子科学与技术学院，武汉光电国家实验室（筹），Britton Chance生物医学光子学研究部，武汉  430074
Published: December 2020

The advantages of using Monte Carlo method for simulating radiative transfer in complex turbid random media like biological tissues are well recognized. However, in most biophotonic applications, the wave nature of probing optical radiation is ignored, and its propagation is considered in terms of neutral particles, the so-called photon packets. Nevertheless, when the fundamental principle of some particular optical techniques for revealing the physiological and pathological information of tissues are based on the interference and polarization or coherent effects of scattering of optical/laser radiation, the wave nature of optical radiation must be considered. In this paper, latest development of Monte Carlo method for simulating light transmission in tissues is reviewed and its bio-photonic applications are presented.
Approximate solution of solitary wave for a class of generalized nonlinear disturbed dispersive equation
Authors: Mo Jia-Qi  , Chen Xian-Feng  ,   (1)安徽师范大学数学系,芜湖 241000；上海高校计算科学院E-研究院上海交通大学研究所,上海 200240; (2)上海交通大学数学系,上海 200240；上海高校计算科学院E-研究院上海交通大学研究所,上海 200240
Published: December 2020

The approximate solution for a class of nonlinear disturbed dispersive equation is considered using a simple and valid technique. We first introduce the solitary wave solution of the corresponding typical differential equation, and then the approximate solution of the singular solitary wave for an original nonlinear disturbed dispersive equation is obtained using the homotopic mapping method.
New kind of inverse problems of Noether’s theory for Hamiltonian systems
Authors: Ding Guang-Tao  ,   安徽师范大学物理与电子信息学院，芜湖  241000
Published: December 2020

In this paper, a new kind of inverse problems of Noether’s theory for Hamiltonian systems is studied. The general solution and the specific solutions of constructing the Hamiltonians and the symmetries from known first integrals by using Noether’s theory are obtained. Two corollaries according to which the conserved quantities can be deduced directly from the Hamiltonians are presented. Two examples are given to illustrate the application of the results.
Security bound of continuous-variable quantum key distribution with discrete modulation
Authors: Shen Yong  , Zou Hong-Xin  ,   国防科学技术大学理学院物理系 长沙 410073
Published: December 2020

Security of continuous-variable quantum key distribution with four-state protocol based on discrete modulation of noisy coherent states is analyzed. Combing discrete modulation and reverse reconciliation, this protocol can be used for long distance cryptography. There is a small difference between the state Alice sends in the discrete modulation protocol and the Gaussian modulation protocol, and it can be treated as excess noise and loss in the channel. As Alice cannot do a precise modulation, she will induce noise to the coherent state. We look this noise as the source noise and derive a lower bound to the secure key rate assuming the eavesdropper cannot benefit from the noise in the source. For avoiding the fast and random phase locking between the signal and local oscillator in experiment, we also analyze the security of four-state protocol using no-switching scheme.
A study on the Lagrangian image of the Birkhoffian representations
Authors: Ding Guang-Tao  ,   安徽师范大学物理与电子信息学院，芜湖  241000
Published: December 2020

The Lagrangian image of the Birkhoffian representations is studied. The conditions that the second-order Lagrangians should satisfy are obtained, under which the generalized Lagrange equations are second-order differential equations. A new way for solving the inverse problem in Lagrange mechanics is presented. An error made in the study by some author is pointed out. Two examples are given to illustrate the application of the result.
Generation of multi-scroll hyperchaotic attractor based on Colpitts oscillator model
Authors: Bao Bo-Cheng  , Liu Zhong  , Xu Jian-Ping  , Zhu Lei  ,   (1)江苏技术师范学院电气信息工程学院，常州 213001; (2)南京理工大学电子工程系，南京 210094; (3)南京理工大学电子工程系，南京 210094；江苏技术师范学院电气信息工程学院，常州 213001; (4)西南交通大学电气工程学院，成都 610031
Published: December 2020

Based on third-order spiral chaotic Colpitts oscillator model, by introducing two piecewise-linear triangular function, a novel four-dimensional multi-scroll hyperchaotic system is constructed, which can generate （2M+1）×（2N+1）, （2M+1） and （2N+1）-scroll chaotic and hyperchaotic attractors. By using phase portrait, Poincaré mapping, Lyapunov exponent spectrum and bifurcation diagram, the dynamical behaviors of the proposed multi-scroll hyperchaotic system are analyzed. These results indicate that Hopf bifurcation point of multi-scroll hyperchaotic system is only related with the control parameter, but its scroll number and ranges of the control parameter for chaotic and hyperchaotic states increase along with the number of turning points. Furthermore, an analog circuit was designed to realize the four-dimensional multi-scroll hyperchaotic system. The results of experimental output and numerical simulation are basically the same.
Research on scattering in microwave chaotic cavity
Authors: Yan Er-Yan  , Meng Fan-Bao  , Ma Hong-Ge  ,   (1)中国工程物理研究院应用电子学研究所，绵阳 621900; (2)中国工程物理研究院应用电子学研究所，绵阳 621900；中国工程物理研究院研究生部，北京 100088
Published: December 2020

The scattering inside the computer box is studied. Some results are found through scattering matrix elements. The ensemble-averaged scattering matrix can be obtained by the measured radiation scattering. With the increase of cavity loss, scattering fluctuations are reduced, and insertion phase shift distribution is becoming more and more uniform. Based on the Dyson’s circular ensemble, the scattering behavior within computer box is found to be chaotic. According to RMT, normalized impedance matrix within the microwave chaotic cavity is universal in their statistical description, depending only upon the value of a single dimensionless cavity loss-parameter.
Study on the parameters determination for reconstructing phase-space in chaos time series
Authors: Zhang Shu-Qing  , Jia Jian  , Gao Min  , Han Xu  ,   燕山大学电气工程学院，河北省测试计量技术及仪器重点实验室，秦皇岛  066004
Published: December 2020

The choice of delay time and embedding dimension have no correlation in the process of phase-space reconstruction. Based on this principle, a new idea for determining the embedding dimension is proposed. It uses CAO theory after determining the delay time by the mutual information function. Numerical simulations show that the method is applicable for determining the appropriate delay time and the best embedding dimension. The method can recover the original phase space from the time series effectively, and can be used as an effective method to identify the chaotic signal.
Study on the rule of light transmission through the four-sided pyramid prism in the static polarization wind imaging interferometer
Authors: Wang Jin-Chan  , Zhang Chun-Min  , Zhao Bao-Chang  , Liu Ning  ,   西安交通大学理学院,非平衡物质结构与量子调控教育部重点实验室,西安  710049
Published: December 2020

The principles of the new static polarization wind imaging interferometer and the light beam splitting of the four-sided pyramid prism were briefly introduced. Both the light ray’s transmitting direction and the transmitted point coordinates in the section of the prism were deduced by the ray tracing method. When the parallel ray had passed through the four-sided pyramid prism, the relation between the incidence angle and the deviation angle was calculated, the relation between the incidence angle and the transmissivity was also calculated. All the above relations were simulated by the computer. According to the parameters of the static polarization wind imaging interferometer, both the angle between the side and the base and the length of the base were determined. This research was very important to the design and manufacture of the static polarization wind imaging interferometer.
Generalization of mode decomposition approach to studies of the synchronization of non-identical coupled dynamical systems
Authors: Pei Li-Jun  , Qiu Ben-Hua  ,   郑州大学数学系，郑州  450001
Published: December 2020

In this paper the mode decomposition approach in the studies of the synchronization of the coupled dynamical systems is generalized to the case of the coupled non-identical dynamical systems by changing the coupling function. The synchronization of the non-identical periodic and quasi-periodic attractor systems is considered detailedly and the conditions for their local synchronization stability are obtained in this paper. The numerical simulation is performed and it was found that the dynamical behaviors of the synchronization are rich. The behaviors include stable synchronized periodic and quasi-periodic solutions in the coupled non-identical quasi-periodic attractor systems，and several stable synchronized periodic solutions in the coupled non-identical periodic attractors， where the new stable synchronized periodic solutions are born due to the coupling，and their attraction basins differe greatly，i.e.，in both of them the multiplicity of the synchronization appears. At the same time the validity of the mode decomposition is also verified.
Tunable pass band of anomalous dispersion photonic crystals
Authors: Liu Jiang-Tao  , Xiao Wen-Bo  , Huang Jie-Hui  , Yu Tian-Bao  , Deng Xin-Hua  ,   (1)南昌大学物理系，南昌 330031; (2)南昌航空大学无损检测技术教育部重点实验室，南昌 330063
Published: December 2020

The influence of laser beam on the transmittance properties of anomalous dispersion photonic crystals （PCs） is investigated. Our calculations show that the pass band of anomalous dispersion PCs is tunable when altering the electron population in the atomic ground state of the anomalous dispersion material by the optical pumping method. With circularly polarized pump light, a huge Faraday rotation can be achieved under weak light intensity. Tunable pass band of anomalous dispersion PCs may lead to important technological applications in the optically controlled optical switch.
Implementing quantum control for the temporal evolution of the wave function of the quantum state by using a phase-controlled light field
Authors: Li Yong-Fang  , Ren Li-Qing  , Ma Rui-Qiong  , Fan Rong  , Liu Juan  ,   陕西师范大学物理学与信息技术学院,西安 710062
Published: December 2020

We investigate the interaction between a two-level atomic system and a phase controllable light field. The quantum diffraction of the population probability for the excited state is described analytically. The physical sense of the wave function evolution is analyzed in detail. The polarization of the atoms is shown with the help of Cornu spiral of the wave function and the temporal evolution of the real and imaginary part for the wave function. It is shown that the polarization of the atoms and the temporal evolution of the wave function as well as the propagation of light can be controlled by manipulating the phase of the light field.
Spectroscopic diagnosis of the relative ionization depth with different buffer gases
Authors: Shao Xu-Ping  , Gong Tian-Lin  , Chen Yan  , Chen Jing-Xia  , Chen Yang-Qin  , Yang Xiao-Hua  ,   (1)精密光谱科学与技术国家重点实验室，华东师范大学物理系，上海 200062; (2)精密光谱科学与技术国家重点实验室，华东师范大学物理系，上海 200062；南通大学理学院，南通 226007; (3)南通大学理学院，南通 226007
Published: December 2020

Using N+2 as the molecular probe, we investigate the ionization behavior of the nitrogen molecule buffered in different rare gases （helium and neon） by optical heterodyne velocity modulation spectroscopy. The spectral intensity of an individual rovibronic line of N+2 is proportional to the product of the velocity modulation index and the concentration of N+2. Therefore, the relative ionization depth can be deduced via measuring the spectral intensity in different buffer gases.
Density functional calculation on the geometric structure and electronic properties of the endohedral fullerene N2@C60
Authors: Gao Hong  , Zhu Wei-Hua  , Tang Chun-Mei  , Geng Fang-Fang  , Yao Chang-Da  , Xu Yun-Ling  , Deng Kai-Ming  ,   (1)河海大学理学院，南京  210098; (2)南京理工大学应用物理系，南京  210094
Published: December 2020

Generalized gradient approximation of density functional theory is used to study the geometric and electronic properties of the endohedral fullerene N2@C60. It is found that the two nitrogen atoms, in the form of N2 molecule, is located at the center of C60. The bonding analysis, energy levels, density of states, and charge analysis show that the effect brought by the N2 molecule on the electronic property of C60 is rather small.
Research on feasibility of closed and offset PCM focusing structures for sheet electron beams
Authors: Zhao Ding  ,   中国科学院电子学研究所,中国科学院高功率微波源与技术重点实验室,北京  100190
Published: December 2020

Using theoretical analysis and numerical calculation, it has been demonstrated that the closed periodic cusped magnetic （PCM） field can effectively confine the sheet electron beam in two transverse directions simultaneously to realize the stable long distance transport, where the beam cross-section has an attainable shape of the state of the art. Moreover, the method for matching the transverse magnetic focusing force and the inner space charge force in the wide dimension of the sheet beam is given, which can be used to determine the longitudinal periodic length and the cross section shape of the closed PCM structure. The calculation has also shown that the optimum focusing can be acquired through adjusting the width of the closed PCM structure independently. And besides, it has been proven that the offset PCM structure is not a good choice for sheet beams’ confinement. The work presented in the paper indicates that the closed PCM structure is very promising, and it’s helpful for guiding the practical engineering design.
Theoretical analysis of the offset-pole periodic cusped permanent magnetic fields
Authors: Du Guang-Xing  , Qian Bao-Liang  ,   国防科学技术大学光电科学与工程学院,长沙  410073
Published: December 2020

The magnetic field excited by the offset-pole periodic cusped permanent magnet （OPPCPM） used for focusing the sheet electron beam has been approximately expressed in two different forms for the convenience of future numerical calculation and theoretical analysis, respectively. Firstly, the surface-current-sheet model has been used to approximate the OPPCPM, and an accurate expression has been obtained using Biot-Savart law. This expression would rather be applied to numerical calculation than theoretical analysis because of the complication. The optimization of entrance taper of the OPPCPM has been performed as an example of application of the expression, implying the high efficiency of the calculation brought by the expression. Secondly, to obtain simple expression of the magnetic field for the convenience of future theoretical analysis, the OPPCPM field has been divided into two parts: the periodic cusped magnetic （PCM） field component and the side-focusing magnetic field component. The expressions of the PCM field component have been obtained using the method of undetermined coefficient, while the expressions of the other one have been obtained using two-magnetic-charge-sheet model. The results are useful to study the transportation of the sheet electron beam in the offset-pole PCM field.
Experiment and processing of MOOC sequences-based optical labels for optical packet switching
Authors: Zhang Chong-Fu  , Qiu Kun  , He Yin  ,   电子科技大学宽带光纤传输与通信网教育部重点实验室,成都  611731
Published: December 2020

The experiment of multiple optical orthogonal codes （MOOC） sequences-based optical labels receiving is reported for the first time. In this work, 2 groups of MOOC with code length 19 and code weight 3 are used to identify optical labels. This paper firstly presents the scheme and principle of optical packets switching networks based on MOOC sequences-based optical labels. Since optical labels contain the optical packet switching and routing information, optical label processing is crucial to achieve successfully packets switching. Therefore, the importance of MOOC-based optical labels processing with multiple inconsecutive, random and burst characteristics in optical packets switching network is pointed out. Considering the MOOC-based optical labels, we design a circuit consisting of widened net and multi-level concatenated amplifiers to receive multiple single-optical-label pulse with a period of 2 ns and low power. The experimental results show that the designed scheme is feasible.
A kinetic model for optically pumped cesium vapor laser
Authors: Zhu Qi  , Pan Bai-Liang  , Chen Li  , Wang Ya-Juan  , Zhang Xun-Yi  ,   浙江大学物理系，杭州  310027
Published: December 2020

The solvent-dependent and frequency-dependent nonlinear optical （NLO） properties of one-dimensional charge transfer （1DCT） molecule, p-nitroaniline （pNA） and two-dimensional charge transfer （2DCT） molecule, 1,3-diamino-4,6- dinitrobenzen （DADB） have been studied by using the density functional theory （DFT） and time-dependent coupled perturbed Hartree-Fork （TDHF） method, respectively. The reasons of the influence of the solvent polarity and incident light frequency on the NLO properties for 1DCT and 2DCT molecules were also discussed. Theoretical results demonstrate that the first hyperpolarizability β and ultraviolet spectra strongly depend on the dielectric constant ε of solvent, but solvent polarity has little effect on the anisotropy ratio η and depolarization ratio D due to the linear relationship between ︱βxxy︱ and ︱βyyy︱ with the increase of the solvent dielectric constant ε. In addition, the incident frequency has a great influence on β,η and D . It is found that the solvent effect and the frequency dispersion effect should be considered in calculations for obtaining accurate results.
The theoretical study and numerical simulation of the tunable two-dimensional hexagonal phase array based on Talbot effect
Authors: Zhou Bo  , Chen Yun-Lin  , Li Yuan-An  , Li Hai-Wei  ,   (1)北京交通大学理学院，北京 100044; (2)北京交通大学理学院，北京 100044；南开大学物理科学学院，天津 300071
Published: December 2020

In this paper, on the basis of Talbot effect and using numerical simulation, we analyzed the two-dimensional amplitude and fixed- phase-difference arrays and found that these arrays can easily be affected by temperature, and the intensity distribution at z position behind them can’t be tuned. To solve the problem, an external electric field is used to tune the phase-difference of the phase array. We derived a theoretical model which realizes uniform distribution of light intensity via the application of an external electric field to tune the phase-difference, and the model agreed with Paturzo’s experimental results. The result make a good foundation for the research of new kinds of arrays.
Fabrication of germanium inverse opal three-dimensional photonic crystal by low temperature plasma enhanced chemical vapour deposition techniques and optical properties
Authors: Li Yu-Jie  , Xie Kai  , Li Xiao-Dong  , Xu Jing  , Han Yu  , Du Pan-Pan  ,   国防科学技术大学材料工程与应用化学系，长沙  410073
Published: December 2020

By the solvent vaporization convection self-assembly method, silica colloidal crystal template was prepared. At 200℃, using GeH4 as the precursor gas, plasma enhanced chemical vapour deposition method was then used to fill the high refractive index material germanium, and germanium inverse opal photonic crystal was obtained. At the temperature lower than the temperature of thermal decomposition, GeH4 filling of germanium is realized. The morphology, composition, and optical property of the resulting samples were characterized by scanning electron microscopy, X-ray diffraction and Fourier transform microscopic IR spectroscopy. Results show that of germanium is amorphous, it is transformed into polycrystalline state by annealing. The germanium is homogeneously distributed inside the voids of silica template. The reflective spectrum of the sample has remarkable optical reflective peaks and shows the photonic band gap effects. The center wavelength of the photonic band gap lies in 1650nm and 2640nm. There is good agreement between the measured spectra and the calculated band structure. Germanium was also deposited on the SU-8 film, this shows that the SU-8 photoresist can with stand the deposition temperature. Low temperature deposition method decreases the deposition temperature. So this method can use macromolecule materials as templates. Thus the three-dimensional photonic crystal with more kinds of structure can be obtained by single-inversion procedure.
Direct numerical simulation on the influence of solid-liquid density ratio on the particle sedimentation under thermal convection
Authors: Tong Zhi-Hui  ,   中北大学能源环境工程与计算流体力学实验室，太原 030051
Published: December 2020

The arbitrary Lagrangian-Eulerian technique was used in the direct numerical simulation of the sedimentation of particle with thermal convection between parallel walls. The fluid motion is computed from the Navier-Stokes equation and energy equation using the finite-element method. The particle was tracked according to the equations of motion of a rigid body under the action of gravity and hydrodynamic forces arising from the motion of the fluid, the model was used without former experience or presumption. The results shows that the particle experiences different regimes of motion: steady motion with and without overshoot and weak, strong and irregular oscillations. The thermal convection changes the sedimentation velocity and the oscillation amplitude of the particle，and the impact of particle by the thermal convection was decreased with solid-liquid density ratio increasing.
Numerical simulation of the near-field distribution of light spot of aperture pyramid-type optical probe with a metal tip
Authors: Wang Guo-Jun  , Wu Shi-Fa  , Li Xu-Feng  , Li Rui  , Duan Jian-Min  , Pan Shi  ,   大连理工大学物理与光电工程学院，大连  116024
Published: December 2020

The finite-difference time-domain method (FDTD) is employed to investigate the near-field distribution of the light spot of aperture pyramid-type optical probe with a metal tip. The factors that have some influence on the electric field distribution such as the length，radius and position departed from aperture of the tip are investigated. The mechanism of electromagnetic wave transmitting from the aperture to metal tip by way of plasmon is discussed. Our calculation results are consistent with the results obtained by Taminiau with different methods. How and why Pohl etc. have obtained images with high resolution in the 20—25 nm range between 1984 and 1986 are analyzed. The imaging mechanism of their experiment system is discussed. Numerical simulation demonstrates that the imaging mechanism of Pohls experiment system may belong to a scattering-type near-field optical microscope (S-SNOM) rather than an aperture scanning near-field optical microscope (A-SNOM). This paper can help us to find optimized tip design in the future.
Study of proton beam spreading for a solid beam stopper double scattering method using Monte Carlo simulation
Authors: Ju Zhi-Ping  , Cao Wu-Fei  , Liu Xiao-Wei  ,   中山大学物理科学与工程技术学院，广州  510275
Published: December 2020

Beam spreading is the foundation of proton therapy for large area and depth tumor. The characteristics of proton lateral beam distribution for a solid beam stopper double scattering system are investigated using Monte Carlo multi-particle transport code Fluka and the results are compared with analytical computation by using Highland formula under the same conditions. It is found that proton fluence obtained by Fluka is lower than that by analytical computation with Highland formula in the region where the variation in uniformity is ±25% and they coincide better with thin-foil than with thick-foil. For a solid beam stopper double scattering system，as the thickness of foils increases，the radius of beam spreading increases，but the efficiency of beam use age increases firstly and then decreases，the maximum value is about 169%.
Ab initio structural simulation and electronic structure of lithium imide
Authors: Yu Da-Long  , Chen Yu-Hong  , Cao Yi-Jie  , Zhang Cai-Rong  ,   (1)兰州理工大学,甘肃省有色金属新材料省部共建国家重点实验室，兰州  730050；兰州理工大学理学院，兰州  730050; (2)兰州理工大学理学院，兰州  730050
Published: December 2020

The crystal structure and the locations of the hydrogen of lithium imide （Li2NH） are studied by first-principle plane wave pseudopotential method based on the density function theory（DFT）. Three models are used to investigating the effects of the Li, N and nearest-neighbor N—H bonds to N—H bond orientation, respectively. The calculated results show that Li2NH crystal can be described by a layered tetragonal crystal （P42） structure. Four N—H bonds of each conventional cell align in two layers. The two imide groups in the same layer prefer to be antiparallel and the imide groups in the nearest-neighbor layers tend to be vertical. The density of states （DOS） and the electron local function （ELF） analysis show strong ionic interaction between the Li and N—H dimmer, while the bonding between the N and H has covalent character. Our P42 structure of Li2NH crystal yields a hydrogen storage Li2NH2+H2/LiNH2+LiH reaction enthalpy of 69.6 kJ/mol H2 at T=0 K, in good agreement with experimental reports of 66 kJ/mol H2 for this reaction.
Model of intrinsic carrier concentration of strained Si/(001）Si1－xGex
Authors: Song Jian-Jun  , Zhang He-Ming  , Hu Hui-Yong  , Dai Xian-Ying  , Xuan Rong-Xi  ,   西安电子科技大学微电子学院，宽禁带半导体材料与器件重点实验室，西安  710071
Published: December 2020

There is great interest in using the strained Si CMOS technology lately for carrier mobility enhancement. Intrinsic carrier concentration is the important physical parameter for the characterization of strained Si materials and the determination of the electrical properties of strained Si-based devices. Starting from analyzing the band structure of strained Si/（001）Si1-xGex，the model of its intrinsic carrier concentration related to Ge fraction （x） at 300 K was established with the frame of K.P theory，which provides valuable reference to the understanding on the strained Si-based device physics and its design.
Transition from spin ice to spin liquid——evolvement of structure and magnetic properties
Authors: Yuan Hui  , Yin Di  , Tang Zheng  , Liu Yong  , Xiong Rui  , Shi Jing  ,   物理科学与技术学院及声光材料与器件教育部重点实验室，武汉大学，武汉 430072
Published: December 2020

The polycrystal samples of Ho2-xTbxTi2O7（x=0，05，1，15，2） were prepared by solid reaction method. The result of X-ray diffraction （XRD） and dc susceptibility measurement from 2 K to 300 K both indicate that as the content of Tb3+，i.e. x，increases，the system crosses over from Ho2Ti2O7spin ice to Tb2Ti2O7 spin liquid，the lattice constant of cubic pyrochlore increases，while the Curie constant and effective magnetic moment decrease. Especially，the Curie-Weiss temperature decreases from positive to negative with the decrease of x，implying the transition from ferromagnetic Ho2Ti2O7 to anti-ferromagnetic Tb2Ti2O7. The detailed analysis shows that as x in Ho2-xTbxTi2O7 increases，the intensity of long-range dipolar interaction Dnn decreases. Being ferromagnetic or anti-ferromagnetic，and the change in intensity of long-range dipolar interaction, may be the two crucial factors influencing on the system to form spin ice state or cooperative paramagnetic state，i.e. the spin liquid state.
Measuring and modeling the spectral bidirectional reflection distribution function of space target’s surface material
Authors: Yuan Yan  , Sun Cheng-Ming  , Zhang Xiu-Bao  ,   北京航空航天大学，精密光机电一体化技术教育部重点实验室，北京  100191
Published: December 2020

An absolute measuring principle and method of bidirectional reflection distribution function （BRDF） is presented. A spectral radiation meter with 3 nm spectral resolution and a three-dimensional rotating system with 001° accuracy are utilized to establish the automatic measuring platform. The spectral BRDF of typical space target’s surface materials （yellow and silver tinfoil） is measured in the range of 400—2500 nm. Measured results show that the scattering angle，which corresponds to the maximum value of BRDF curve，is generally in the specular reflection direction；the other BRDF values change slowly as scattering angle varies，declining from middle to both sides and approximately following the cosine distribution. A BRDF error analysis method is introduced by using the RMS error calculation，which provides a new way for the BRDF measurement system evaluation. The measurement error is 495%. With five-parameter model of BRDF and the simulated annealing （SA） algorithm，the optimum parameters of the model at each wavelength in the measured spectrum are retrieved at intervals of 1 nm. A comparison of the data calculated by the parametric model with the data measured originally verifies the feasibility and reliability of the modeling. The measuring and modeling results can provide reference data for space target detection and identification.
Optical transparency and development of failure in quartz glass under dynamic load
Authors: Li Yong-Hong  , Liu Fu-Sheng  , Ma Hai-Yun  , Cheng Xiao-Li  , Ma Xiao-Juan  , Sun Yan-Yun  , Zhang Ming-Jian  , Xue Xue-Dong  ,   西南交通大学高温高压物理实验室，成都  610031
Published: December 2020

Optical transmission of quartz glass is measured during loading and unloading process，and the stress was kept below their Hugoniot elastic limit. The results show that the quartz glass maintains good transparency for more than 15 μs under loading processes of 18 GPa，then it starts to lose its transparency about 07 μs after unloading，with 30% decrease of transmittance. This phenomenon，which reflects the growth and evolution of failure induced by unloading process in quartz glass，has been explained reasonably by the growth of spherical particles and the scattering model. The results are different from the explanation of liquid-solid phase transition given in literature［J. Chem. Phys. 2004，121 9050］. This paper is significant for studying the transparency of other transparent material.
Preparation and properties of Sn-Ti alloy anode material for lithium ion batteries
Authors: Hou Xian-Hua  , Hu She-Jun  , Shi Lu  ,   华南师范大学物理与电信工程学院，广州 510006
Published: December 2020

Nano-sized Sn-Ti alloy anode material prepared by magnetic sputtering was characterized with X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The charge/discharge and cyclic voltammograms of the films electrodes were tested by the high precision battery testing system. The results indicated that the Sn/Ti compound films and Ti/Sn compound films have large difference in performance. Sn/Ti compound films have excellent cycling stability and tolerably high reversible capacity. Its initial discharge specific capacity and charge specific capacity are 9275 mAh/g and 6954 mAh/g, respectively，and the initial capacity fade is 25%. After 30 cycles，specific discharge capacity of 4152 mAh/g was retained and the coulombic efficiency was the same as the value before 30 cycles. This is ascribed to the isolation effect of inactive element Ti between active element Sn and the electrolyte.
Stress exponent and threshold stress of in situ TiCp/LD7Al matrix composite in creep
Authors: Ji Feng  , Song Ai-Jun  , Zhang Wei-Guo  , Hao Qiu-Hong  , Bai Bang-Wei  , Liu Ri-Ping  , Ma Ming-Zhen  ,   (1)亚稳材料制备技术与科学国家重点实验室，燕山大学，秦皇岛  066004; (2)亚稳材料制备技术与科学国家重点实验室，燕山大学，秦皇岛  066004；河北科技师范学院，秦皇岛  066004; (3)亚稳材料制备技术与科学国家重点实验室，燕山大学，秦皇岛  066004；巨龙钢管有限公司，清县  062658
Published: December 2020

The elevated temperature creep behavior of in situ 20vol%TiCP/LD7Al matrix composite and LD7Al alloy was investigated under the condition of constant compressive stress at 523 K，573 K and 623 K，respectively. The stress exponents of the composite material and the matrix aluminium alloy were obtained by fitting the creep rate and the applied stress in log-log plot，respectively. By introducing an effective stress （σ-σ0） to the power equation and extroplating the linearly-regressed experemental data to zero creep rate，the threshold stresses were obtained. The results showed that both the stress exponents and the threshold stresses of the composite were higher than those of LD7Al，indicating that the presence of TiC particles significantly improved the elevated temperature creep property of LD7Al. By introducing a threshold stress，the high-temperature creep behavior of the composite can be explained by the cooperative effect of the dislocation-climbing and the particle hindrance to the matrix deformation.
Approximation solution of a class of disturbed sea-air coupled oscillator mechanism
Authors: Zhou Xian-Chun  , Lin Wan-Tao  , Lin Yi-Hua  , Mo Jia-Qi  ,   (1)安徽师范大学数学系，芜湖 241000; (2)南京信息工程大学，电子与信息工程学院，南京 210044; (3)中科院大气物理研究所，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 box model of the interhemispheric thermohaline circulation in the disturbed sea-air for globe climate is considered. By using the homotopic mapping method，a class of nonlinear model is studied, and the approximate solution is obtained. The homotopic mapping solving method is an analytic method，the solution obtained can be analytically operated sequentially. And then we can also study the diversified qualitative and quantitative behaviors of corresponding physical quantities.
A universal law on general reflected short-crested waves—— frequency-doubling route to short-crested waves
Authors: Huang Hu  , Yang Li  , Xia Ying-Bo  ,   上海大学上海市应用数学和力学研究所，上海  200072
Published: December 2020

Considering ambient uniform currents, a third-order analytic solution for short-crested waves arising from a general partial reflection from a vertical breakwater is presented, thus reaching a universal law: frequency-doubling route to short-crested waves.
Investigations on molecular structure and analytic potential energy function of the AsH(X3Σ-) and AsH2(C2v，X2B1) radicals
Authors: Shi De-Heng  , Liu Hui  , Sun Jin-Feng  , Zhu Zun-Lüe  , Liu Yu-Fang  ,   (1)河南师范大学物理与信息工程学院，新乡  453007; (2)空军第一航空学院基础部，信阳  464000; (3)信阳师范学院物理电子工程学院，信阳  464000
Published: December 2020

The CCSD(T) theory in combination with the cc-pV5Z basis set is used to determine the equilibrium geometry，dissociation energy and vibrational frequencies of AsH2(C2v，X2B1) radical. By comparison，excellent agreement can be found between the present results and the experiments. The values obtained at present are of 01508 nm for the equilibrium bond length RAs-H，912231° for the bond angle ∠HAsH，28795 eV for the dissociation energy De(HAs-H) and 10133361 cm-1，22251347 cm-1 and 22337565 cm-1 for the vibrational frequencies ν1(a1)，ν2(a1) and ν3(a1)，respectively. The equilibrium geometry，harmonic frequency and potential energy curve of the AsH(X3Σ-) radical are calculated at the CCSD(T)/cc-pV5Z level of theory. The ab initio results are fitted to the Murrell-Sorbie function with the least-square method. The spectroscopic parameters are in excellent agreement with the experiments. The analytic potential energy function of the AsH2(C2v，X2B1) radical is derived by using the many-body expansion theory. This function correctly describes the configuration and dissociation energy of the AsH2(C2v，X2B1) radical. Two symmetrical saddle points have been found at (0160 nm，0296 nm) and (0296 nm，0160 nm)，respectively. And the barrier height is equal to 01512×4184 kJ/mol.
Octupole deformation in even-even Ra isotopes
Authors: Jiao Peng  , Guo Jian-You  , Fang Xiang-Zheng  ,   安徽大学物理与材料科学学院,合肥  230039
Published: December 2020

The octupole deformation of even-even Raisotopes has been investigated systematically by the reflection asymmetric relativistic mean field (RAS-RMF) theory. The results are compared with the experimental data together with the results from FRDM. It is shown that RAS-RMF theory gives a good description for Ra isotopes. The calculated binding energy, two neutron separation energy and deformation agree with the experimental data well. In particular, RAS-RMF theory provides the neutron and proton densities which show clearly the shape evolution of these nuclei from nearly spherical to well-developed octupole and finally back to quadrupole deformation shapes. This is in accordance with experimental observation.
A new method for predicting the induced magnetic field of naval vessels
Authors: Chen Jie  , Lu Xi-Wen  ,   华东理工大学理学院，上海  200237
Published: December 2020

A method based on magnetization is proposed to predict the induced magnetic field of naval vessels. We first deduce a formula to calculate the magnetic field in the internal region of magnetized objects from the viewpoint of magnetization，and then use the formula to define the point-function demagnetizing tensor and prove some properties of the tensor. Finally we use this formula to develop a new method to predict the induced magnetic field of naval vessels in a nonuniform applied field，and we call it the Magnetization Method，in which the point-function demagnetizing tensor is used. Compared with traditional methods，the magnetization method features low computational cost，high precision and manifest physical meaning. A numerical simulation of ship model verifies the method.
Application of fluorescence spectra based on radial basis function neural network in identification of bacteria
Authors: Wu Hao  , Zhu Tuo  , Kong Yan  , Chen Wei  , Yang Jian-Lei  ,   江南大学理学院，无锡  214122
Published: December 2020

The results of research on fluorescence spectra of three kinds of probiotic bacteria (lactobacillus acidophilus, streptococcus mutans and lactobacillus bulgaricus) show that the bacteria emit fluorescence when irradiated by ultraviolet light. The spectra are in the range of 300—650　nm with the excitation wavelength of 290　nm. Wavelet transform is used to compress the 150 groups of spectra data, and the number of data points in each group is reduced from 1341 to 168, which not only keeps the character of original spectra unchanged, but also improves the processing speed of neural network. Radial basis function neural network is applied for processing the compressed data. 40 groups of data of each strain are used to be trained, and the other 30 groups of data of which the kinds of bacteria are not given are used for prediction. The result shows that radial basis function neural network can identify the unknown bacterial strain accurately.
Scattering of bi-sphere arbitrarily illuminated by a single beam and a dual beam
Authors: Han Guo-Xia  , Han Yi-Ping  ,   西安电子科技大学应用物理系,西安  710071
Published: December 2020

In the framework of the generalized Lorenz-Mie theory (GLMT), the scattering of arbitrarily incident shaped beam by dielectric bi-sphere is investigated. By expressing the incident beam with arbitrary incidence angle in terms of the spherical vector wave function, we derive the scattering equations of bi-sphere arbitrarily illuminated by a single beam, and then extend to the case of scattering of dual-beam. As an example, numerical computations for the scattered intensities of bi-sphere randomly irradiated by a single Gaussian beam and by two Gaussian beams are presented respectively after numerical verifications. In particular, the scattering properties for the two cases are compared and discussed theoretically in detail with respect to different parameters such as incident angle, center-center separation, etc.
Imaging quality enhancement by deconvolution in spectral domain optical coherence tomography
Authors: Wang Kai  , Zeng Yan  , Ding Zhi-Hua  , Meng Jie  , Shi Guo-Hua  , Zhang Yu-Dong  ,   (1)浙江大学光电信息工程学系，现代光学仪器国家重点实验室，杭州  310027; (2)中国科学院光电技术研究所，成都  610209
Published: December 2020

Deconvolution methods are not feasible in spectral domain optical coherence tomography (SD-OCT) system due to the linear space variant property of its axial point spread function (PSF). In order to improve the axial resolution and enhance the imaging quality of the SD-OCT system, a Lucy-Richardson algorithm based deconvolution method is implemented with the numerically compensated A-scan signals and the effective axial PSF in this paper. The main factors decreasing the value of PSF along the axial direction and blurring the images, as well as the deconvolution process, are theoretical studied. With the developed SD-OCT system, the axial modulation function of the PSF is retrieved by curve fitting of the measured peak values of the PSF at different axial positions. After compensating the A-scan signal with the modulation function, deconvolution is performed with the measured effective axial PSF. In vivo imaging on typical samples is conducted and reconstruction is done based on the deconvolution method. The comparing results demonstrate that the proposed deconvolution method not only enhances the axial resolution but also improves the depth dependent sensitivity fall-off in SD-OCT system.
One-way deterministic secure quantum communication protocol based on single photons
Authors: Quan Dong-Xiao  , Pei Chang-Xing  , Liu Dan  , Zhao Nan  ,   西安电子科技大学综合业务网理论及关键技术国家重点实验室,西安 710071
Published: December 2020

One-way deterministic secure quantum communication protocol based on single photons is proposed in this paper, in which the XOR operation by bits of the information sequence and random sequence is performed and the checking sequence is inserted before the sender’s coding operation. When the photons arrive at the receiver, they are delayed at the receiver, and the sender then publishes the coding basis, so the photons can be measured in the correct basis. Then the two parties estimate the security of the quantum channel by the checking bits. When the channel is secure the sender publishes the random bits where the receiver has results, and the information sequence can be recovered by the receiver. Even the channel is not secure, what the eavesdropper gets is the random sending sequence, the information sequence is still secure. This protocol has the advantages of higher transmission efficiency and easier implementation compared with the two-way communication.