bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of the warhead temper thickness by γ-ray spectra
Authors: Xiong Zong-Hua  , Kang Wu  , Gong Jian  , Hu Guang-Chun  , Xiang Yong-Chun  , Pei Yong-Quan  ,   中国工程物理研究院核物理与化学研究所，绵阳  621900
Published: December 2020

The high-resolution γ-ray detection technology is a kind of reliable technologies to verify nuclear warhead.In this paper,the relationship that the γ-ray intensity emitting from warhead varies with the thickness of the absorber is studied by modeling calculation and experimental demarcation.A more compendious method to analyze the temper thickness and its application conditions are also discussed.
The application of modern radio-frequency excitation theory in nonhomogeneous fi eld magnetic resonance imaging
Authors: Zhang Bi-Da  , Wang Wei-Dong  , Song Xiao-Yu  , Zu Dong-Lin  , Lü Hong-Yu  , Bao Shang-Lian  ,   (1)北京大学重离子物理研究所，北京市医学物理和工程重点实验室，北京  100871; (2)北京大学重离子物理研究所，北京市医学物理和工程重点实验室，北京  100871;解放军总医院，北京  100853
Published: December 2020

In the problem of nonhomogeneous field magnetic resonance imaging (MRI),echo peaks decay quickly due to traditional design of radio frequency (RF) pulse.In this article,using inverse scattering transform (IST) of the nonlinear dynamics and Shinnar-Le Roux selective excitation pulse design algorithm (SLR Algorithm),we have designed the RF pulse for the nonhomogeneous field MRI.Simulation has been made to test the signal loss induced by the excitation of different types of RF pulses.Simulation results show that the RF pulse sequence optimized by IST and SLR algorithm can improve the signal to noise ratio of MRI considerably
Numerical simulation of liguid alloy flow field during solidification under applied pulsed magnetic fields
Authors: Zi Bing-Tao  , Yao Ke-Fu  , Xu Guang-Ming  , Cui Jian-Zhong  ,   (1)东北大学材料与冶金学院,沈阳  110004; (2)清华大学机械工程系,北京  100084
Published: December 2020

A numerical simulation of the flow field during solidification in Al-alloy was corried out by the ANSYS 55 in the present paper. The simulation results were in good agreement with the experimental data. It was found, through the simulation, that not only the melt's movement but also the mechanism of the refinement for the solidified structure and the formation of some defaults during solidification were elementally understood.
The vector diffraction theory analysis of chromatic dispersion characteristics o f phase grating
Authors: Bayanheshig  , Qi Xiang-Dong  , Tang Yu-Guo  ,   中国科学院长春光学精密机械与物理研究所，长春  130022
Published: December 2020

In this paper broad sense grating equation and broad sense chromatic dispersion formula that can be applied to reflection and transmission regions of phase grating in arbitrary oblique angle of incidence are discussed based on the vector diffraction theory. At the same time, the theoretical and numerical analyses for the chromatic dispersion capabilities of the phase grating are made to confirm the reciprocal restricted relation among the incident angle, the incident azimu thal angle, the incident wavelength, the grating period, the refractive index of the substrate in the diffraction area, and the order of diffraction,then the re stricted inequality of grating can be constructed. On the other hand, all possib ilities of improving the chromatic dispersion are presented.
Research on bifurcation behaviour and chaos control in DC-DC buck converter
Authors: Luo Xiao-Shu  , Wang Bing-Hong  , Guanrong Chen  , Quan Hong-Jun  , Fang Jin-Qing  , Zou Yan-Li  , Jiang Pin-Qun  ,   (1)广西师范大学物理与电子科学系，桂林  541004; (2)华南理工大学应用物理系，广州  510641; (3)香港城市大学电子工程系，九龙  香港; (4)中国科学技术大学近代物理系，合肥  230026; (5)中国科学技术大学近代物理系，合肥  230026;广西师范大学物理与电子科学系，桂林  541004; (6)中国原子能科学研究院，北京  102413
Published: December 2020

In this paper,the bifurcation behaviour and chaos control are investigated for a DC-DC buck converter with load capacitor.Some valuable new results are obtained,e.g.,the periodicity adding windows are found in this circuit system and the measure of chaotic motion is found to converge to zero asymptotically increasing load capacitance.Moreover,it is found that the transform ratio of voltage for periodict motion is higher than that for the chaotic motion in the buck converter.These results have some applications for designing practical circuits.At the same time,chaotic behaviours of this circuit system can be effectively controlled by applying suitable periodic impulses to the system.
Formation and emission spectra of C2 swan band during the reaction of laser ablating target of aluminum with CF4 beam
Authors: Zhang Shu-Dong  , Li Hai-Yang  ,   (1)中国科学院安徽光学精密机械研究所环境光谱学实验室，合肥  230031;中国科学院研究生院，北京  100039; (2)中国科学院安徽光学精密机械研究所环境光谱学实验室，合肥  230031;中国科学院研究生院，北京  100039;西北师范大学物理与电子工程学院，兰州  730070
Published: December 2020

The emission spectra of C2 Swan band transition has been observed in the 430nm-600nm region by Qswitch laser ablating target of Al and reacting with CF4 beam.Five vibrational band sequences (Δv=2,1,0,-1 and -2) of d3Πga3Πu are identified and the largest vibrational number of the excited state d is 6.Using a local thermal equilibrium model, the vibrational temperature of d state is about 6340K. Emission spectra from AlF have not been found. Comparing with the results of laserablated Al+O2 system and similar experiment of Cu+CF4 system, while the timeofflight profile of Al(2P1/2-2S1/2,3944nm)and(0,0)band head of C2 are analyzed, we consider that the primary reason of the producing of excited state d3Πg is the electronic energy transformation between excited states Al(2S1/2) and C2.
Forecasting of the realtime data monitored by differential optical absorption spectroscopy method
Authors: Qi Feng  , Liu Wen-Qing  , Zhou Bin  , Li Zhen-Bi  , Cui Yan-Jun  ,   中国科学院安徽光学精密机械研究所，合肥  230031
Published: December 2020

Differential optical absorption spectroscopy (DOAS) has become a widely used method to measure trace gases in the atmosphere.Their concentrations can be retrieved by a numerical analysis of the atmospheric absorption spectra. But it has been found that DOAS could not gain continuous data under a bad weather condition.Thus it could not fully fit for the demand of the environment monitoring statute.A prediction technology has been developed, based on the stepwise regression analysis method.It is shown that the forecasting data using this method is consistent with the real data after doing a great deal of experiments. This technology has been used in practice.
Forward Raman scattering in the wake-field induced by short-pulse laser
Authors: Xu Han  , Chang Wen-Wei  , Zhuo Hong-Bin  ,   国防科技大学理学院，长沙  410073
Published: December 2020

We analyse the influence of forward Raman scattering(FRS) on the wake-field induced by ultra-intense short-pulse laser with a 25D PIC simulation model. FRS is the major unstable mechanism that draws out the length of scattering pulse, as well as steeps the tail of the laser. Therefore, the wake wave phase velocity decreases obviously and the maximum electron kinetic energy trapped is much less than the conventional theoretic value. Furthermore, the frequency spectrum profile shifts to lower freguency.
Core polarization and the calculation of lifetimes of highs series Rydberg state s of Na atom
Authors: He Li-Ming  , Yang Yue  , Lu Hui  ,   华东理工大学物理系，上海  200237
Published: December 2020

The model-potential method including correlation effects is applied to the computation of lifetimes of high s series Rydberg states of Na atom.This theoretical model does not depend on the experimental results.In comparison,the results agree well with experiments and provide the evidence of the validity of this theoretical method.
A study on the resonator of multi-rod series connection solid-state lasers
Authors: Xi Zai-Jun  , Zheng Qi-Guang  , Qin Ying-Xiong  , Yu Ben-Hai  , Tong Xing-Lin  ,   华中科技大学激光技术国家重点实验室，武汉  430074
Published: December 2020

Resonator parameters and thermo-stability conditions for plane-plane resonator o f multi-rod series connection solid-state lasers were investigated by means of m atrix optics.Stability areas of six-rod-connection solid-state lasers in a plane -plane resonator were calculated.The results show that stability areas and non-s tability areas of the multi-rod series-connection solid-state lasers distribute alternately.If the length of the resonator,the number(n) of laser rods and the s pacing (L) between two neighbouring laser rods are given and a symmetry configur ation (L1=L2) is adopted,then every stability area reaches a largest extent. If the condition (L1=L2=L/2) is supposed in plane-plane re sonator and the th ermo focus length (f) is greater than a lower limit value (fm),the st ability c ondition (01G2m),the resonator come into a deep non-stability area.The lower limit va lue (fm) is determined by the number (n) of laser rods and the spacin g (L) between two rods,the formula is fm=0.25L(if 2≤n≤10).
High-order harmonic generation by laser interaction with solid target using movi ng mirror model
Authors: Li Kun  , Zhang Jie  , Yu We  ,   (1)中国科学院上海光学精密机械研究所强光光学开放研究实验室，上海  201800; (2)中国科学院物理研究所光物理开放实验室，北京  100080
Published: December 2020

Using the moving mirror model,we studied analytically the harmonic generation from solid targets illuminated by intense laser pulses.Comparison of the results o f the moving mirror model with those of particle-interaction computor simulations and experiments reveals the shortcomings of this model though it can really give many useful characters of the process of high-order harmonic generations.
Study on the mechanism of heat conduction in nanofluid medium
Authors: Xie Hua-Qing  , Xi Tong-Geng  , Wang Jin-Chang  ,   中国科学院上海硅酸盐研究所,上海  200050
Published: December 2020

The heat conduction behaviour in a nanofluid fluid medium has many abnormal properties. Combined with the analysis based on microscale heat transfer theory and the physicochemical behaviours of nanofluid, the mechanism of heat conduction in nanofluid has been studied. The effects of nonlinear heat transfer in nanoparticle, micro convection are caused by the Brownian movement of nanoparticles, congregation of nanoparticles, and orderly array of liquid molecules at the interface between the nanoparticle surface and the base fluid.
Microscopic structure studies on the diamond films fabricated by chemical vapor deposition method
Authors: Liu Cun-Ye  , Liu Chang  ,   (1)拉特格斯大学物理与天文学系，美国新泽西  08854; (2)西南师范大学物理学系,重庆  400715
Published: December 2020

The microscopic structures of the diamond films generated on Si (100) substrates by chemical vapor deposition have been studied by x-ray wide angle diffraction spectroscopy, grazing incidence x-ray scattering spectra, positrons annihilation lifetime spectroscopy, and qualitative software and Positronfit program. The di ffraction x-ray spectra show a structure difference between the near substrate p art (NSP) and near free-surface part (NFP) of the diamond film specimens, which reflect the weak ［111］texture in NSP and the strong［220］ texture in NFP. The positron annihilation lifetime spectroscopy of the specirnens and the analyzing data indicate that the majority of positrons annihilate around 200 ps and 400 p s. The vacancies, vacancy clusters, and voids were found in the film specimens, depending on the processes in which the chemical vapor deposition is generated.
Structural and magnetic properties of RCo12-xTix(R=Y and Sm) compounds
Authors: Wang Wen-Quan  , Yan Yu  , Wang Xue-Feng  , Su Feng  , Wang Xiang-Qun  , Jin Han-Min  ,   (1)吉林大学物理学院，长春  130023; (2)吉林大学物理学院，长春  130023;吉林大学超硬材料国家重点实验室,长春  130023
Published: December 2020

Magnetic and structural properties of RCo12-xTix with R=Y and Sm compounds have been investigated by using x-ray diffraction and magnetic measurements. It was found that all compounds investigated are almost of a single phase with the ThMn12-type structure. x-ray diffraction patterns of magnetically aligned powder samples indicate that the easy magnetization directions (EMD) at room temperature are in the basal plane for SmCo12-xTix compounds while for YCo12-xTix compounds the EMDs are along the c-axis. The lattice parameters increase monotonically with increasing Ti content for all the compounds investigated. The Curie temperature Tc decreases monotonically with increasing Ti content for both YCo12-xTix and SmCo12-xTix. The saturation magnetization Ms decreases with increasing Ti content for all the systems. The anisotropy field μ0Ha of YCo12-xTix compounds decreases monotonically with increasing Ti content, while the Ti content dependence of the anisotropy fields μ0Ha for SmCo12-xTix compounds exhibits a maximum at about x=1.74, which can be understood in terms of a two-sublattice model of anisotropy.
High temperature heat-electric phenomenon of Tb4O7 doped W O3 ceramics
Authors: Yang Xin-Sheng  , Chen Min  , Wang Yu  ,   华中科技大学物理系,武汉  430074
Published: December 2020

Heat-electric properties at high temperatures were measured on tungsten trioxide (WO3) ceramics doped with Tb4O7 prepared by c onventional solid-sintering method. The results indicated that a phase transition occurred at 350℃ on heating and 270℃ on cooling with a large thermal hysteresis of about 80℃. And the samples can provide an electric energy output at a constant temperature of 500℃, which cannot be explained by the known thermoelectric or pyroelectric effect. We regard it as a new heat-electric effect, by which a new way of converting heat energy to electric energy may be found.
Investigation of stable high-index silicon surfacesby means of LEED pattern analysis
Authors: Jiang Jin-Long  , Li Wen-Jie  , Zhou Li  , Zhao Ru-Guang  , Yang Wei-Sheng  ,   北京大学物理系，人工微结构和介观物理国家重点实验室，北京  100871
Published: December 2020

In the course of a systematic search for stable silicon surfaces, we have studied four stable high-index silicon surfaces, i.e., Si(1,1,11), (1 0 8), (2 1 2), and (15,1,17), by analyzing their low-energy electron diffraction (LEED) patterns. The results show not only that all these surfaces are stable but also that Si(15,1,17) is a major stable surface,whereas the rest three are minor stable surfaces, meaning that their unit cells consist of a nanometer facet of a major stable surface along with a double height step. In view of the periodic facet-step morphology of these minor stable surfaces, we suggest that these surfaces have the potential to be used as templates for growth of periodic nanowires of some suitable materials.
Exact solutions to two nonlinear equations
Authors: Zhang Jin-Liang  , Wang Yue-Ming  , Wang Ming-Liang  , Fang Zong -De  ,   (1)河南科技大学数理系，洛阳  471039; (2)河南科技大学数理系，洛阳  471039;兰州大学数学系，兰州  730000; (3)西北工业大学机电工程学院，西安  710072
Published: December 2020

By using the traveling wave reduction method, the exact solutions to the (1+1)-d imensional Zakharov equation, Korteweg-de Vries equation with variable coefficie nts are obtained with the aid of exact solutions to the cubic nonlinear Klein-Go rdon equation-
The thermodynamical calculations of uranium-water vapor system
Authors: Xiong Bi-Tao  , Meng Da-Qiao  , Xue Wei-Dong  , Zhu Zheng-He  , Jiang Gang  , Wang Hong-Yan  ,   (1)四川大学原子分子物理研究所，成都  610065; (2)中国工程物理研究院，绵阳  621900
Published: December 2020

In this paper, we study the relative stable molecular structures of uranium-wate r vapor system- For the uranium atom were used the relativistic effective core p otential and contracted valued basis sets (6s5p2d4f)/[3s3p2d2f], and for oxygen and hydrogen atoms were used 6-311G** basis sets- We obtain the elect ronic state, geometric structure, energy, harmonic frequency, mechanical property, et c-，of these six quintuple relative stable structures- It indicated that the first step of uranium-water vapor reaction is the interaction of uranium and oxyg en atoms- The thermodynamical stability of UOH2(5A1) was calculated an d its disassociation Gibbs free energy ΔG°decreased with increasing temper ature -The result showed that low temperature favoured its existence-
Experimental study of shock wave propagating character in targets driven by an i nclined-incident laser
Authors: Fu Si-Zu  , Huang Xiu-Guang  , Wu Jiang  , Wang Rui-Rong  , Ma Min-Xun  , He Ju-Hua  , Ye Jun-Jian  , Gu Yuan  ,   (1)中国工程物理研究院上海激光等离子体研究所，上海  201800; (2)中国工程物理研究院上海激光等离子体研究所，上海  201800;同济大学波耳固体物理研究所，上海  200092
Published: December 2020

With the folding target and double-step target,the propagating character of shock wave driven by an inclined-incident (with angle of ～45°) laser was studied on “Shenguang-Ⅱ” high-power laser facility.The result indicated that the shock wave in the target still propagates along the vertical direction to the target surface.Also the same result was verified indirectly by another experiment based on the measurement for spatial intensity distribution of x-ray radiated from jet plasmas.
The propagator for an arbitrary integral spin
Authors: Huang Shi-Zhong  , Zhang Peng-Fei  , Ruan Tu-Nan  , Wu Ning  , Zheng Zhi-Peng  ,   (1)中国高等科学技术中心(世界实验室)，北京  100080;中国科学技术大学近代物理系和国家同步辐射实验室，合肥  230027; (2)中国高等科学技术中心(世界实验室)，北京  100080;中国科学技术大学近代物理系和国家同步辐射实验室，合肥  230027;安徽师范大学物理系，芜湖  241000; (3)中国高等科学技术中心(世界实验室)，北京  100080;中国科学院高能物理研究所，北京  100039
Published: December 2020

Based on the solution to Bargmann-Wigner equation for an arbitrary integral spin , a further investigation on the projection operator and propagator for an arbit rary integral spins is carried out. The explicit form of the projection operator s for integral spins constructed by Behrends and Fronsdal is checked and confirm ed; the commutation rules and general expressions for the Feynman propagator for a free particle of an arbitrary integral spin are derived.
Finite-element methods for viscoelastic and azimuthally anisotropic media
Authors: Du Qi-Zhen  , Yang Hui-Zhu  ,   (1)清华大学工程力学系,北京  100084; (2)清华大学工程力学系,北京  100084;石油大学（华东）地球资源与信息学院,东营  257061
Published: December 2020

With the importance of the fractured strata in the oil exploration, researchers have paid more attention to the wave propagation in viscoelastic and anisotropic media. Provided the rocks are weakly viscoelastic, the viscoelastic problems can be solved as a series of elastic problems by using the time increment method. At each step we determine the viscoelastic deformations and the corresponding viscoelastic loads, which are added to the load vectors for the next step. On this basis, the finite-element recursive formulae of viscoelastic and azimuthally anisotropic media are established. The numerical simulations show the characteristics of wavefields in the viscoelastic and azimuthally anisotropic media.
Form invariance for a constrained system with second-order reducible differentia l constraints
Authors: Ge Wei-Kuan  , Zhang Yi  ,   (1)湖州师范学院物理系,湖州  313000; (2)苏州科技学院土木工程系,苏州  215011
Published: December 2020

A form invariance for mechanical systems with second_order reducible differential constraints is studied．Two methods to study the form invariance of the systems are used．In the first method，the system is considered as a nonholonomic system with second_order and in the second method it is considered as a system after reduction．The relation between the two methods is obtained．The result proves that it is possible that some symmetries are lost in the second method．
Sandwich-like segregation in vertically vibrated binary granular mixtures
Authors: Jiang Ze-Hui  , Lu Kun-Quan  , Hou Mei-Ying  , Chen Wei  , Che n Xiang-Jun  ,   (1)中国科学院物理研究所,北京  100080; (2)中国科学院物理研究所,北京  100080;哈尔滨工业大学应用物理系,哈尔滨  150001
Published: December 2020

In a vertically vibrated binary granular mixture, sandwich-like segregation pattern is observed; a layer of large heavy particles is sandwiched in between two layers of small particles. This pattern is different from the double-layer structure, known as the “Brazil nut” effect, where the large heavy particles populate on the top. Our experiments show that such a three-layer structure is a stable pattern. It occurs when the vibration acceleration is beyond a critical threshold. Two different segregation processes are observed. The mechanisms for these two segregation processes are discussed. The dependence of the segregation pr ocesses on the driving frequency f and acceleration　Γ, and the size ratio and volume ratio of the particles are also experimentally studied.
The domain-state orbital liquids in a one-dimensional spin-orbital model
Authors: Zhang Shi-Yong  ,   长安大学基础部，西安  710064
Published: December 2020

A one-dimensional integrable spin-orbital model is studied. In the large spin li mit, the degrees of freedom of the spin part can be described by the classical I sing spins. Without the external magnetic field, the ground state of the system is a connected orbital liquid with the background of Ising antiferromagnetic ord er of spins. The elementary excitations are the usual spinon-like orbital quanta . In an external magnetic field, flux phase exists in the system. The fluxes(two parallel ising spins)cut the system into disconnected orbital liquids(domains).
A novel,yet direct,parameter-extraction method for heterojuction bipolar transis tors small-signal model
Authors: Liu Hai-Wen  , Sun Xiao-Wei  , Cheng Zhi-Qun  , Che Yan-Feng  , Li Zheng-Fan  ,   (1)上海交通大学电子工程系，上海  200030; (2)中国科学院上海微系统与信息技术研究所，上海  200050; (3)中国科学院上海微系统与信息技术研究所，上海  200050;上海交通大学电子工程系，上海  200030
Published: December 2020

An accurate and broad-band method for heterojuction bipolar transistors(HBT) small-signal model parameters is presented in this paper.This method differs from previous ones by extracting the equivalent-circuit parameters without using spec ial test structure or global numerical optimization techniques.The main advantag e of this method is that a unique and physically meaningful set of intrinsic par ameters is extracted from impedance and admittance representation of the measure d S-parameters in the frequency range of 0.5—12GHz under different bias conditi ons.An equivalent circuit for the HBT under a forward-bias condition is proposed for extraction of access resistance and parasitic inductance.The method yields a deviation of less then 5% between measured and modeled S-parameters.
Entropy of Dirac field in a general spherically symmetric and charged evaporatin g black hole
Authors: Zhang Jing-Yi  ,   湛江师范学院物理系，广东湛江  524048
Published: December 2020

By using the thin film model,which is based on the brick-wall method,the entropy of the Dirac field in a general spherically symmetric and charged evaporating black hole is calculated.The conclusion that black hole entropy is proportional to its horizon area can still be applied by regulating the cutoff,which is time dependent.
Simulation investigation on multi-scroll chaotic and hyperchaotic attractors for four-dimensional systems
Authors: Yu Si-Min  , Lin Qing-Hua  , Qiu Shui-Sheng  ,   (1)广东工业大学信息工程学院，广州  510643;华南理工大学电子与信息学院，广州  510640; (2)广东工业大学应用物理系，广州  510643; (3)华南理工大学电子与信息学院，广州  510640
Published: December 2020

On the basis of double scroll chaotic attractors,taking the modified Chua's circuit and fourth-order Chua's circuit as examples,a new method for study chaotic and hyperchaotic attractors with multi-scroll in four-dimensional systems is presented.According to this method,the recursion rules used to generate multi-scroll attractors are mathematically obtained.Only given initial values of ma,mb and x1,according to the presented recursion formulas,can the values of other breakpoints and equilibrium points of a piecewise linear characteristic in multi-scroll attractors be determined,and multi-scroll chotic and hyperchaotic attractors for 4D systems generated.This method can be applied to generating attractors having any scrolls with general regularity.Theoretic analysis,computer and circuit simulation results have proved the feasibility of this method.
Study on the properties of the dynamic partially coherent speckle in the Fresnel and Fraunhofer diffraction regions
Authors: Teng Shu-Yun  , Cheng Chuan-Fu  , Liu Man  , Liu Li-Ren  , Xu Zhi-Zhan  ,   (1)中国科学院上海光学精密机械研究所,上海  201800; (2)中国科学院上海光学精密机械研究所,上海  201800;山东师范大学物理系,济南  250014
Published: December 2020

We have studied the properties of the dynamic partially coherent speckles in the Fresnel and Fraunhofer diffraction regions. We use the theory of propagation of the mutual intensity in partially coherent light, and derive the general form of the spatio-temporal cross-correlation functions of the dynamic speckle intensities produced by a moving diffusing object. Based on these theoretical expressions, the characteristics of the movement and the boiling of the dynamic partially coherent speckles are discussed. By choosing the proper extended incoherent light source and by adjusting the parameters of the optical setup, we have observed experimentally the partially coherent speckle in the Fresnel and Fraunhofer diffraction regions. Then we study qualitatively the movement and the boiling of the speckles. Using techniques of photon counting and automatic data acquisition, we have measured the temporal evolution of the speckle intensity in the Fraunhofer plane as the object moves, and thus measured the cross-correlation of the speckles versus the temporal increment. The experimental data are in agreement with the theoretical results.
The theoretical calibration coefficient in the measurement of nonlinear dielectric constant with a scanning tip microwave near-field microscopy
Authors: Liu Xue-Rong  , Hu Bo  , Liu Wen-Han  , Gao Chen  ,   中国科学技术大学物理系，合肥  230026;中国科学技术大学国家同步辐射实验室，合肥  230026
Published: December 2020

In this paper,the interactions between the tip of the scanning tip microwave near-field microscopy and the nonlinear dielectric material were analyzed.The theoretical calibration coefficient in the measurement of nonlinear dielectric constant as a function of dielectric constant was obtained.The contributions to the coefficient from different directions and the resolution limit were also discussed.
Measurement of femtosecond laser pulses using SHG frequency-resolved optical gating technique
Authors: Wang Zhao-Hua  , Wei Zhi-Yi  , Teng Hao  , Wang Peng  , Zhang Jie  ,   中国科学院物理研究所光物理开放实验室，北京  100080
Published: December 2020

We present a measurement of femtosecond laser pulses using the technique of second harmonic generation frequency-resolved optical gating (FROG) in this paper. Based on the data of the correlation signal in time and frequency domains, we obtained the detailed information on pulse shape, bandwidth, pulse duration and phase by using the retrieval algorithm program. The pulse duration is in reasonable agreement with the measurements using an interferometric autocorrelator.
The general solution of noncircular uniform optical waveguides in an arbitrary coordinate system and applications
Authors: Wu Chong-Qing  , Dong Hui  , Fu Song-Nian  , Liu Hai-Tao  ,   (1)北方交通大学电信学院，北京  100044; (2)北方交通大学理学院，北京  100044
Published: December 2020

This paper presents the general solution of noncircular uniform waveguides in an arbitrary coordinate system. It can be expressed as exp{i(+ΔβV)z}E0(x,y),where V is a matrix depending uniquely on the angle θ between polarization principal axis (PPA) and coordinate axis. As a kind of application, we give the method to find , Δβ and V(θ) in the weak-guided fiber, whose distortion is smaller.It is easier to use it for analyzing the effect of birefringence decreasing due to the lognitudinal asymmetry in a fiber, compared with Jones matrix.
The influence and control of incoherent irradiation on photorefractive nonlinearity of LiNbO3:Fe crystal
Authors: Wang Da-Yun  , Liu Si-Min  , Chen Xiao-Hu  , Zhao Hong-E  , Guo Ru  , Yang Li-Sen  , Gao Yuan-Mei  , Huang Chun-Fu  , Lu Yi  ,   (1)内蒙古师范大学物理系，呼和浩特  010022; (2)南开大学物理学院，天津  300071; (3)南开大学物理学院，天津  300071;北京师范大学物理系，北京  100875; (4)天津理工学院自动化系，天津  300191
Published: December 2020

In this paper,we study the influence of incoherent irradiation on the conversion process from self-defocusing to self-focusing in LiNbO3:Fe crystal under the open-circuit condition.We observe that the incoherent irradiation can increase the refractive index change, fasten greatly the process of self-defocuisng, self-focusing and the conversion from the former to the latter in LiNbO3：Fe crystal, whether it propagates along the direction of the incident light or the opposite direction. When the incoherent light illuminates the crystal in certain time intervals repeatedly, the transmissivity can rise up and fall down quickly, the obvicus switching effect is observed. The change of the refractive index controlled by the incoherent irradiation can be applied in the all-optical switch.
A family of S-mKdV hierarchy of equations and its expanding integrable models
Authors: Zhang Yu-Feng  , Yan Qing-You  , Zhang Hong-Qing  ,   (1)大连大学先进设计技术中心，大连  116622; (2)大连理工大学机械学院，大连  116024; (3)山东科技大学信息学院，泰安  271019;中国科学院计算数学与科学工程计算研究所，北京  100080
Published: December 2020

Starting from a subalgebra of loop algebra 1 we construct a linear isospectral problem.A type of Liouville integrable system and its bi-Hamiltonian structure are presented by the use of Tu-model again.The reductions to the integrable system give rise to the well-known Schrdinger equation and mKdV equation.Therefore,the system is called S-mKdV hierarchy.In terms of the subalgebra of A constructed,we also construct a new subalgebra G of loop algebra A with five dimensions,from which a linear isospectral form is designed.Again,using Tu-model one obtains a type of expanding integrable models of the S-mKdV hierarchy.Some expanding integrable models of hierarchies,such as BPT hierarchy,TB hierarchy etc.are also obtained by using this method.Hence,the method proposed in this paper has important applications generally.Finally as special cases,the integrable couplings of the well-known Schrdinger equation and mKdV equation are obtained.
Investigations of the photon fluences in various n+γ\=mixed fields in the fast neutron reactor
Authors: Lei JiaRong  , Yuan Yong Gang  , Zhao Lin  , Zhao Min Zhi  , Cui Gao Xian  ,   中国工程物理研究院核物理与化学研究所，绵阳  621900
Published: December 2020

The LET factors RＬＥＴ(RＬＥＴ≈005) of neutron response for LiF(Mg,Cu,P)TLD have been determined experimentally due to the existing LET effects of the response for LiFTLD to neutron absorbed dose.Based on the data,one experimental method to define the photon fluence in various n+γ mixed fields in the fast neutron reactor with coupled 6LiF7LiFTL detectors has been checked.The experimental results show that the ratios of the TL due to the effect of neutrons in 7LiF(Mg,Cu,P)to the total TL due to the combined effects of the γrays and neutrons are between 81% and 17.1%.In order to reduce the effect caused by the uncertainty of the neutron spectra and improve the accuracy of the measurement for the photon fluence,we propose a new LiFTLD,in which there are 50% 6LiF and 50% 7LiF.It is coupled with a 6LiFTLD to measure the photon fluence in the n+γ mixed fields.
Fitting the data of nonexotic structural nuclear total reaction cross section with a corrected Glauber model
Authors: Li JiaXing  , Guo ZhongYan  , Xiao GuoQing  , Zhan WenLong  , Wang JianSong  , Sun ZhiYu  , Wang Meng  , Tian WenDong  , Wang WuSheng  , Mao RuiShi  , Wang QuanJin  , Ning ZhenJiang  , Wang JianFeng  ,   中国科学院近代物理研究所，兰州  730000
Published: December 2020

In the theoretical calculation of total reaction cross section, the results can fit the experimental data very well at high energy, but they are about 10%—20% lower at intermediate energy. In this work the finite range correction has been added to the Glauber model, and a Fermidensitydistribution with two parameters has been chosen as the input density distribution of the nucleus. This shows that the results of the theoretical calculation are in agreement with the experimental one for nonexotic structural nucleus, both at high and intermediate energy regions.
Optimization of chirped-pulse amplification systems using Martinez stretcher
Authors: Song Yan-Rong  , Zhang Zhi-Gang  , Wang Qing-Yue  ,   天津大学精密仪器与光电子工程学院，光电子信息技术科学国家教育部重点实验室，天津  300072
Published: December 2020

This paper presents an analytical formula for calculating the phase of a Martinez stretcher in which a‘phase correction term' is added- From this phase expression, the group delay and higher-order dispersions are easily extracted- The calculated group delay evaluated the contribution of the Martinez stretcher to the system dispersion, and the formula is used to optimize the complete chirped-pulse amplification systems-
Hard magnetic Pr55Al12Fe30Cu3 bulk metallic glass
Authors: Li Zheng  , Bai Hai-Yang  , Zhao De-Qian  , Pan Ming-Xiang  , Wang Wan-Lu  , Wang Wei-Hua  ,   (1)中国科学院物理研究所,北京  100080; (2)中国科学院物理研究所,北京  100080;重庆大学数理学院应用科学与技术系,重庆  400044; (3)重庆大学数理学院应用科学与技术系,重庆  400044
Published: December 2020

In this paper we report the formation of a new Pr55Al12Fe30Cu3 bulk metallic glass. Cylindrical Pr55Al12Fe30Cu3 specimens of 5 mm in diameter and 100 mm in length were prepared by copper mold suction casting. Differential scanning calorimetry results indicated that the Pr-based bulk metallic glass system has a wide supercooled liquid region about 64K. The melting temperature of the amorphous state is about 140K higher than that of its crystalline state. Hysteresis loops were measured, and the results indicated that the Pr55Al12Fe30Cu3 bulk metallic has hard magnetic property, while the completely crystallized alloy has soft magnetic property at room temperature.
Quantum random number generator based on polarization
Authors: Feng MingMing  , Qin XiaoLin  , Zhou ChunYuan  , Xiong Li  , Ding LiangEn  ,   光谱学与波谱学教育部重点实验室，华东师范大学物理系，上海  200062
Published: December 2020

We present a set of random number generator based on a quantum mechanical source,which is the process of splitting a beam of photons on a polarizing beam splitter.The randonmess of the polarizing photon is detected by the synchronous singlephoton coincidence detection technique.The random bit data are transferred to a personal computer via a digital I/O interface.The random numbers are tested by the Pseudorandom Number Sequence Test Program(ENT) which is the most popular random number test program in the world.The result is perfect.
Condition of Alfven Gauss wave-packet evolvement to solitons and criterion of Alfven wave modulation instability
Authors: Zhang Jie-Qiu  , Liang Chang-Hong  , Wang Geng-Guo  , Zhu Jia-Zhen  ,   (1)西安电子科技大学电子工程学院，西安  710071; (2)西安电子科技大学天线与微波技术国家重点实验室，西安  710071; (3)西安电子科技大学天线与微波技术国家重点实验室，西安  710071;空军工程大学工程学院，西安  710038
Published: December 2020

By analyzing the integral constant C1 of Alfven solitons, the condition of Alfven Gaussian wave-packets evolvement to solitary waves is put forward as C1≤0. This hypothesis is also confirmed by numerical simulation results. Furthermore,simulation results show that the number of evolving solitons does not depend only on integral constant C0 or C1. The conclusions in Refs. ［1］ and ［2］ result from the shorter evolving time. Comparing with other papers, we find that C0≤0 can be used as a criterion of Alfven wave modulation instability.
Optimization of diffraction properties for holographic polymer dispersed liquid crystal
Authors: Zhang Bin  , Liu Yan-Jun  , Xu Ke Shu  , Jia Yu  ,   (1)复旦大学化学系,上海  200433; (2)复旦大学先进光子材料与器件国家重点实验室，光科学与工程系,上海  200433
Published: December 2020

Holographic polymer-dispersed liquid crystal (HPDLC) is a kind of switchable volume holography. It can be manufactured according to the photo-initiated polymerization-induced phase separation. HPDLC is composed of parallel, periodic polymer-rich and liquid crystal-rich planes. The diffraction efficiency can be modulated by the application of electric field. HPDLC devices are potentially useful for optical communication, information storage and display. How to increase the diffraction efficiency is the key to application. We investigated the dependence of diffraction efficiency on the refractive index of the polymer, exposure intensity, liquid crystal loading and temperature. The best conditions were found to make the diffraction properties optimized. Now the highest diffraction efficiency was 802%. The HPDLC morphologies were also observed and analyzed by scanning electron microscope (SEM).
Negative thermal expansion of the Ho2AlFe14Mn2 compound
Authors: Hao Yan-Ming  , Cui Chun-Xing  , Meng Fan-Bin  ,   (1)河北工业大学材料学院，天津  300130; (2)天津师范大学物理系，天津  300074
Published: December 2020

The structure properties of Ho2AlFe16-xMnx compounds have been investigated by means of x-ray diffraction and magnetic measurements. The Ho2AlFe16-xMnx compounds have a hexagonal Th2Ni17-type structure. Their unit-cell volumes increase nonlinear with increasing x. This implies there is a positive spontaneous volume magnetostriction in the magnetic state of these compounds. x-ray diffraction of the Ho2AlFe14Mn2 compound from 160 to 285 K shows that there appears a negative coefficient of thermal expansion from 220 to 270K and the average thermal expansion is -14×10-4·K-1.
Choosing Teaching as a Career: Perspective of Pre-Service Teachers in Cameroon
Authors: Atemnkeng Nkemngong , Akum Futella Christine , Ngwokabuenui Ponfua Yhayeh , Chu Ambei Moses
Published: December 2020

The Higher Teachers’ Training Colleges (HTTCs) and Higher Teachers’ Technical Training Colleges (HTTTCs) in Cameroon prepare all teachers seeking to be employed within the education service in Cameroon. In the last decade, Ecole Normale Superieur (ENS) and Ecole Normale Superieur d’Enseignement Technique (ENSET)’s enrolments for initial teacher preparation programs have grown significantly, with peaks in numbers during the recession years. There is also some evidence of attrition when beginning teachers complete their 3-year courses with the Ministry of Higher Education, which sponsors their teacher education program. This research sought to investigate the principal determining factors that are extrinsic, intrinsic and altruistic to choosing teaching as a career in Cameroon. It also investigated the expectations and the plans of pre-service teachers in Cameroon. The study was carried out within a duration of 6 months with a total of 210 (125 females and 85 males) teacher trainees in their first year, involved in the study. The types of motivation when choosing teaching as a career were studied using ‘Teaching Career Choice Scale’. The model of motivation types was supplemented by subscales: Influenced by others, Career growth, motivation and alternative choice. The findings of the study revealed that male and female student teachers have similar motives in selecting teaching as a career. The mean scores for both genders were closely related. For altruistic factors, the mean ranges respectively for males and females were 32.41 and 32.26. Extrinsic factors stood at 40.18 and 37.06 respectively. Intrinsic and altruistic factors motivated teachers the less, scoring a mean range of 26.07 and 26.14. This paper also discussed the findings in relation to wider issues concerning gender, and drew conclusions which may be helpful to policy-makers and institutions in the recruitment of students into pre-service teacher training.
Modeling Life Time Data by Generalized Weibull-generalized Exponential Distribution
Authors: Badmus N. I. , Olanrewaju Faweya,
Published: December 2020

This paper convolutes two generalized distributions from the family of generated T - X distribution. The new distribution generated from these distributions is called the Generalized Weibull-generalized Exponential Distribution. The properties of the proposed distribution are derived. Method of maximum likelihood estimation is used to estimate the parameters of the distribution and the information matrix is obtained. Thereafter, the distribution is applied to a real life dataset of failure for the air conditioning system and the obtained results are compared with other existing distributions to illustrate the capability and flexibility of the new distribution.
Safety Evaluation of Fermotein: Allergenicity, Mycotoxin Production, Biochemical Analyses and Microbiology of a Fungal Single-cell Protein Product
Authors: Spiegel Marjolein van der , Driessche José J. van den , Leune Elisa , Pařenicová Lucie , Laat Wim de
Published: December 2020

Aim: Single-cell proteins (SCPs) are considered as innovative and sustainable alternatives to animal-based products. Fermotein is an innovative SCP obtained from fermentation of the filamentous fungus Rhizomucor pusillus. The toxicity, capability to produce secondary metabolites and allergenic potential of this fungus has never been assessed before. Like other filamentous fungi, there is a lack of information on this species to assess its safety for human consumption. The objective of the current study was to investigate the safety of Fermotein and its source Rhizomucor pusillus regarding toxicity, capability to produce secondary metabolites and allergenicity. In addition, possible contaminants were also examined.

Methodology: The genome of Rhizomucor pusillus was sequenced and annotated in order to screen for production of common mycotoxins, antibiotic synthesis pathways, mucormycosis-related virulence factors and in silico potential cross-reactivity with known food allergens. The presence of mycotoxins and allergens were validated by laboratory analysis. The level of RNA, heavy metals and microbiological contaminants were also determined.  

Results: No mycotoxin production-related genes were identified in the genome of Rhizomucor pusillus nor were mycotoxins found in Fermotein. Six proteins present in Fermotein showed high homology with five known food allergens. No gene clusters were found that corresponded with antibiotic synthesis pathways. Although 10 proteins in the genome of Rhizomucor pusillus may represent mucormycosis-related virulence factors, no cases of mucormycosis after oral intake are reported. The level of heavy metals and microbiological contaminants were below legislative limits, whereas RNA content was 4.9 ± 0.2% of dry matter.

Conclusion: No safety concerns were identified for Fermotein or its source Rhizomucor pusillus, except the potential for cross-reactivity with five known food allergens. This should be taken into account for communication with consumers. Information from the current study contributes to the body of evidence for determination of Qualified Presumption of Safety status of Rhizomucor pusillus.
Constraints Faced by Guava Growers in Adoption of Guava Production Technology and Suggestions for Suitable Extension Strategies to Overcome the Problem in Bijnor District of UP
Authors: Singh Desh Pal , Prakash Satya , Kumar Vikas , Singh Krishna Kumar , Sharma Prerna
Published: December 2020

Guava grown in diverse agro-climatic conditions faces differential biotic and abiotic stress that limiting the production and productivity of guava and consequently, influenced the economic condition of its growers. Keeping these facts in mind, the present study was conducted in Bijnor district of UP to find out the constraints faced by guava growers in adoption of production technology and suggest suitable extension strategies to overcome the problems. Two villages from 11 blocks were selected randomly on the basis of orchard availability. Five guava Growers was selected from each selected village. Thus, the total sample size for the investigation was 110 respondents who faced constraints in adoption of guava production technology. The guava respondents faced the constraints in adoption of guava production technology. Total constraints mainly divided into five groups. Among the input constraints, unavailability of quality chemicals like plant growth regulator, water soluble fertilizer and plant protection chemicals at government sale centre got first rank with 77.27 percent respondent, followed by unavailability of quality sapling of guava at Government nursery (73.64 percent). Among the technological constraints, lack of knowledge about organic farming of guava got first rank with 91.82 percent respondents followed by lack of knowledge about drip irrigation schedules (89.09 percent). Among the socio- psychological constraints, lack of coordination among the beneficiary and state/district horticulture department got the first rank with 92.73 percent respondents followed by inadequate extension activities conducted by state/district horticulture department (88.18 percent). Among the marketing constraints, exploitation of guava growers by middlemen got first rank with 92.73 percent respondents followed by lack of quality storage facility (87.27 percent). Among the financial constraints, lack of government funding of loan and granting of subsidies got first rank with 94.55 percent followed by high labour charges (92.73 percent). Lack of knowledge about organic farming of guava was identified as major constraints in qualitative guava production. It is therefore suggested the extension workers should organize guava growers in different groups of organic farming. They should plan knowledgeable programmes for the respondents so they can be motivated to what the organic farming of guava and can increase their knowledge about quality guava production practices through extension work like group discussion, training, demonstrations, exhibition, etc. The growers therefore are required to be educated to follow up all the recommended production practices for guava, use of timely inputs, nutrients and plant protection management practices which will help in increasing the production and productivity.
Infertility and Depression: Frequency of Depression in Infertile Males
Authors: Jamali Anwar Ali , Kumar Haresh , Tunnio Safdar Ali Parvez , Rind Shahbuddin , Lohano Ashok Kumar , Jamali Ghulam Mustafa , Tanwani Bhojo Mal
Published: December 2020

Background: There is increasing concern that the depression may be associated with infertility.

Objective: The current research was aimed to explore the frequency of depression in infertile males.

Study Design: This was a cross sectional study.

Duration: March 2016 to September 2018.

Place: Department of Medicine, PUMHS Nawabshah, Pakistan.

Materials and Methods: A total of 385 infertile male subjects who reported for the semen analysis at young age group were included in the study. Depression was assessed by using Hamilton Depression Rating Scale. Data was collected via self-made proforma and analyzed by using SPSS version 20.

Results: A total of 385 infertile males were studied. Mean age of individuals was 30.28+6.18 years. Mild depression was found in 34.8% patients, moderate depression was seen in 18.2% patients, severe depression was in 8.1% patients and very severe depression was in 9(2.3%) patients. Moderate and severe depression was higher in cases of Oligospermia and Azoospermia as compared to those having normal sperm count, while results were statistically insignificant (p=0.747).

Conclusions: In the observation of this study, there was a significant relationship between infertility and depression in infertile males. Depression was found in 64.6% of infertile males, ranging from mild to very severe levels.
Clinical Presentation and Mortality of Women Presented with Puerperal Sepsis at Tertiary Care Hospital
Authors: Samreen Erum , Abbasi Madiha , Parveen Naheed
Published: December 2020

Objective: To determine the clinical presentation and mortality of women presented with puerperal sepsis at tertiary care Hospital.

Materials and Methods: This cross-sectional study was conducted at obstetrics and gynaecology department of Liaquat University of medical and health Sciences, from April 2018 to march 2019. Women having age more than 15 years and presented with sepsis after birth followed by spontaneous vaginal delivery, instrumental or episiotomy vaginal delivery or caesarean section were included. All the data including clinical features and mortality were recorded by study proforma. Data was analyzed by using SPSS version 20.

Results: Most of the patients 46.6%, having age between 26 to 35 years. Majority of the patients 48.3% were delivered by normal vaginal delivery (NVD) and 37.9% underwent caesarean section, while 13.8% given birth as NVD with episiotomy. Almost all cases presented with fever and other common clinical features were abdominal pain, vaginal discharge, wound infection and breast tenderness. According to the maternal outcome 24.1% patients were shifted to intensive care unit (ICU), 34.5% had prolonged hospital stay and mortality rate was 10.3%. There was no significant difference in maternal outcome according to mod of delivery; p-values were quite insignificant.

Conclusion: It was concluded that puerperal sepsis is a major contributing factor of  maternal adverse outcome. Common clinical features were fever, abdominal pain and vaginal discharge.