bluuebunny/crossref_metadata_2025 huggingface dataset:
Formación en derecho basada en competencias
Authors: Carreño Bustamante María Teresa , Goyes Moreno Isabel , Pabón Mantilla Ana Patricia
Published: December 2020

Esta obra hace referencia a las competencias para la formación de los estudiantes de derecho en Colombia, desde las discusiones que a nivel nacional se suscitan a partir de la evaluación en pruebas saber pro, por la preocupación constante de los programas de derecho hacia la formación de personas íntegras con responsabilidad social; por ello, este libro pretende aportar a dicha discusión, desde la perspectiva de una formación crítica, investigativa y participativa que permita fundamentalmente la consolidación de comunidades académicas jurídicas que dediquen su esfuerzo, no solamente a una formación teórica del estudiante sino también práctica y contextualizada, asegurando la formación de sujetos competentes para las necesidades de este país. Finalmente, pretende proponer alternativas curriculares para la organización de contenidos y ante todo, espacios de interacción con los estudiantes.
A series of new exact solutions to the (2+1)-dimensional Broer-Kau-Kupershmidt equation
Authors: Zhi Hong-Yan  , Wang Qi  , Zhang Hong-Qing  ,   (1)大连理工大学应用数学系,大连116024; (2)大连理工大学应用数学系,大连116024;中国科学院数学机械化重点实验室,北京100080
Published: December 2020

With the aid of computer symbolic systems Maple, and by an improved algebraic method which is used to construct a series of more general exact solutions to nonlinear differential equation or coupled equations, we have solved the (2+1)-dimensional Broer-Kau-Kupershmidt equation, and obtained a number of new exact solutions including polynomial solutions,exponential solutions, rational solutions, triangular periodic solutions,hyperbolic solutions, and Jacobi and Weierstrass doubly periodic wave solutions.
Analysis on the principle of multilevel optical data recording and the study on the processing of the front signals of a multilevel read-write system
Authors: Xiao Jia-Xi  , Qi Guo-Sheng  , Hu Hua  , Xu Duan-Yi  ,   清华大学精密仪器与机械学系光盘国家工程研究中心，北京  100084
Published: December 2020

This paper utilized the calculation methods in vector diffraction theory, such as the wave_coupled method and the finite difference time domain method, to a nalyze two multilevel optical recording methods in principle. Meanwhile the prin ciple to achieve multilevel optical recording by modulating the amplitude of pha se_change media is also discussed. According to these analysis, the multilevel d ata recording utilizes the mutual action between laser and recording media. Lase r beam has some special effects on the media; simultaneously the media will modu late some characteristics of the light. Generally, the diversities of these cha racteristics are more than two states, so the multilevel data recording can be a chieved by recording these different states. Besides, the design and development of the front signals processing system is also presented. It is an important pa rt of the experimental system for multilevel recording. It can output some servo and error signals such as TE, FE and RF etc, which will be fed back to the appr opriative chip for multilevel recording. Additionally the processing system not only can control the laser power and the writing time of the optical pickup, but it also can make the pickup realize focusing and tracking automatically.
Entanglement for excitons in three quantum dots in a cavity coupled to a broadband squeezed vacuum
Authors: Tan Hua-Tang  , Gan Zhong-Wei  , Li Gao-Xiang  ,   华中师范大学物理科学与技术学院，武汉  430079
Published: December 2020

The dynamical behavior of purity and entanglement for excitions in three quantum dots placed in a cavity driven by a broadband squeezed vacuum is studied in the low exciton density regime. It is found that the excitions in the three quantum dots can evolve into a pure entangled state only when the dissipation of the cavity and excitions is negligible. When the injected field into the cavity is a squeezed vacuum, the excitions will be in a three_mode Gaussian entangled mixed state even in the long time limit .Analytical expressions are derived showing the dependence of the purity and entanglement property of the excitions in the three quantum dots on the squeezing properties of the initial state prepared in the cavity and the strength of two_photon correlations of the squeezed vacuum injected into the cavity.
Mechanism of broad acoustic band-gap in the three-component composite
Authors: Hua Jia  , Zhang Shu  , Cheng Jian-Chun  ,   南京大学近代声学国家重点实验室，南京  210093
Published: December 2020

Mechanism of broad acoustic band_gap in the two_dimensional three_component composite is investigated by calculating acoustic transmission spectra and acoustic fields for different inserted steel rows embedded in epoxy resin matrix with or without rubbers as the coating material. By comparing the acoustic fields inside the two_ and three_component crystal slabs, one can conclude that the broad acoustic band_gap in the three_component crystal slab is formed by the coexistence of the Bragg reflection of a periodic structure and the localized resonance in the soft rubber. The former is evidence in higher frequency and the latter is dominant in lower frequency with the wavelength longer than that of the coating layer.
Molecular dynamics simulation of atomic configurations at γ/γ′(001）interface in Ni-based single-crystalline superalloys
Authors: Geng Cui-Yu  , Wang Chong-Yu  , Zhu Tao  ,   (1)钢铁研究总院功能材料研究所，北京  100081; (2)钢铁研究总院功能材料研究所，北京  100081;清华大学物理系，北京  100084;中国科学院国际材料物理中心，沈阳  110016
Published: December 2020

In this paper, three different atomic configurations at γ/γ′（001）interface in Ni_based single_crystalline superalloys has been studied by means of molecular dynamics. The most stable atomic configuration was obtained by energetics calculation. Among the three configurations analyzed, dynamics simulation results show that a pairs of edge misfit dislocations appeared at all the relaxed interfaces. The related calculations reveal that the system energy, the interface formation energy and the relaxed energy are determined by the stacking sequence, while the geometric character of different atomic configurations is the same. That is, different atomic configurations at γ/γ′（001）interface have the same strain relief mechanism.
Structure and magnetic properties of CoPt(FePt)-C nanocomposite films
Authors: Wang Hao  , Yang Fu-Jun  , Xue Shuang-Xi  , Cao Xin  , Wang Jun-An  , Gu Hao-Shuang  , Zhao Zi-Qiang  ,   (1)北京大学物理学院重离子物理教育部重点实验室，北京100871; (2)湖北大学物理学与电子技术学院，武汉430062
Published: December 2020

CoPt(FePt)C nanocomposite thin films were prepared by a pulsed filtered vacuum arc deposition technique. Thermal annealing was performed in vacuum at various temperatures. The dependence of the magnetic properties on the carbon fraction and annealing temperature was studied. Both xray diffraction and magnetic force microscopy analyses confirmed the formation of nanocrystallites of facecenteredtetragonal phase of CoPt or FePt in the carbon matrix after annealing at a sufficiently high temperature. For the film with particular compositions of Co24Pt31C45 and Fe43Pt35C22,the coercivity and the grain size were observed to increase with increasing annealing temperature. For the Co24Pt31C45 film at an annealing temperature of 700℃, the coercivity was 2.1×105 A/m and the grain size was about 17nm. For the Fe43Pt35C22 film at an annealing temperature of 650℃, the values were 2.8×105 A/m and 105nm,respectively.
Field-induced displacement properties of nanoscale domain structure in PZT thin film
Authors: Zeng Hua-Rong  , Yu Han-Feng  , Chu Rui-Qing  , Li Guo-Rong  , Yin Qing-Rui  , Tang Xin-Gui  ,   (1)广东工业大学应用物理学院，广州510090; (2)中国科学院上海硅酸盐研究所高性能陶瓷和超微结构国家重点实验室，上海200050
Published: December 2020

Nanoscale characterization of fieldinduced displacement was made in compositionally graded PZT thin film according to the inverse piezoelectric effects by SFM in contact mode. The nanoscale piezoelectric displacement  electric field butterfly loop was obtained due to the combined contribution from linear piezoelectric effect and domain switching effect, which substantiate nanoscale validity of CaspariMerz theory. The nanoscale imprint phenomena were also observed in the thin film.
Studies on a nonequilibrium atomic cluster system with repulsive interactions
Authors: Di Guo-Qing  , Zhang Bang-Jun  , Ye Gao-Xiang  ,   (1)浙江大学环境科学系，杭州  310028; (2)浙江大学环境科学系，杭州  310028;浙江大学物理系，杭州  310027; (3)浙江大学物理系，杭州  310027
Published: December 2020

A simulation model for diffusion and aggregation of atomic clusters with repulsi ve interactions on nonlattice substrates is established, and the aggregation pro cess of the silver atoms on charged silicone oil surfaces has been studied. It w as found that after the stable atomic clusters form, due to the repulsive intera ction among the clusters, the number density of the atomic clusters decays with time exponentially and the time constant is Oaa; statistically, the relative speed V between two clusters increases linearly with their distance L according to V=HL, where the constant H≈Oaa after deposition and then approaches zero with time. With the increase of the viscosity coefficient o f liquid substrates, the friction force increases and H decreases. A linear relation between the friction force and H is found with the slope k≈0 10±001 We show that the critical radius r11 of the clusters, abo ve which the atomic clusters start to carry charges, is related nearly to the at omic affinity, i.e., the energy needed for the cluster to carry an extra electro n. It is found that H and Oaa increase slowly with r11 and their slopes are 12±03s-1-1μm-1-1 and 16±06s-1-1μm-1-1, respectively. Our simulation results are in agreement w ith the previous experimental findings.
Small angle x-ray scattering study on microstructure and mechanical property evo lutions of equal-channel angular pressed 7050 Al alloy
Authors: Zheng Li-Jing  , Li Shu-Suo  , Li Huan-Xi  , Chen Chang-Qi  , Han Ya-Fang  , Dong Bao-Zhong  ,   (1)北京航空航天大学材料科学与工程学院,北京  100083; (2)中国科学院高能物理研究所,北京  100039
Published: December 2020

Three processes which combined equal_channel angular pressing (ECAP) with heat t reatment were applied to fabricate super_high strength fine 7050 Al alloy. Varia tions of microstructure parameters of precipitates in 7050 Al alloys were analyz ed by using small angle x_ray scattering technique. The variations of mechanical properties and mechanism of strengthening in 7050 Al alloys were explained in the paper. Experiments discovered that “pre_ECAP solid solution treatment and post_ECAP aging treatment" was a proper process, with which the ultimate tensile strength was increased to 677MPa, and elongation to failure was improved to b e 15% or so.
First-principles calculations on the mercury vacancy in Hg050.5 Cd050.5Te
Authors: Sun Li-Zhong  , Chen Xiao-Shuang  , Zhou Xiao-Hao  , Sun Yan-Lin  , Quan Zhi-Jue  , Lu Wei  ,   中国科学院上海技术物理研究所红外物理国家重点实验室,上海  200083
Published: December 2020

Using the density-functional theory within the full-potential linear augmented plane wave method, we have calculated the influence of the mercury vacancy on the bonding mechanism and the relaxation effects in the Hg050.5Cd 050.5Te (MCT) alloy. The bonding charge density and charge transf er gave the explanation for the relaxation results. The results of density of st ates revealed that the re-coupling of the dangling bond of the nearest neighbor (NN) of the vacancy make the NN Te 5s state energy level shift up. The reasons for the energy level shift were discussed with the Te s-state bonding charge density. The results of the partial density of state at the band edge reveal that the mercury vacancy will narrow the band gap of the MCT materials.
Computational study on the exchange-correlation function in density functional theory and optical nonlinearity of transition-metal complexes
Authors: Zhang Ming-Xin  , Wu Ke-Chen  , Liu Cai-Ping  , Wei Yong-Qin  ,   中国科学院福建物质结构研究所结构化学国家重点实验室,福州  350002
Published: December 2020

Dipole moments, polarizabilities and first hyperpolarizabilities of a series of transition metal complexes have been studied by employing various exchange-correlated potentials within the density functional theory (DFT). Taking into consideration the basis set and frequency-dispersion effects, the efficiencies of these potentials have been calibrated by comparing with the ab initio results of MP2, HF and experimental measurements. The effect of different portion of exchanged-correlated functional of hybrid-DFT on dipole moment, polarizability and first hyperpolarizability has been discussed as well.
Lowering of ordering temperature for L100-FePt in Fe/Pt multilayers
Authors: Li Bao-He  , Hwang Pol  , Yang Tao  , Zhai Zhong-Hai  , Zhu Feng-Wu  ,   (1)北京科技大学材料物理与化学系,北京  100083; (2)北京科技大学材料物理与化学系,北京  100083;北京工商大学数理部,北京  100037; (3)北京科技大学材料物理与化学系,北京  100083;金日成综合大学物理系,朝鲜平壤
Published: December 2020

Fe/Pt multilayers and FePt thin films were prepared by DC magnetron sputtering. The as-prepared samples were subjected to vacuum annealing at temperatures in t he range of 300—550℃. The multilayered structure is an effective approach fo r reducing the ordering temperature of FePt. The ordering parameter S is evaluated to be 06, and correspondingly the coercivity is evaluated to be 501kA/m in ［Fe(15nm)/Pt(15nm)］1313 multilayers annealed at 350℃ for 20min. Relatively low ordering temperature for the multilayer is due to the e xtra driving force of ordering process caused by the vanishing of the multilayer interface at annealing.
Mechanical properties of the single-phase Ti-Zr-Ni quasicrystalline alloy at roo m-temperature
Authors: Qiang Jian-Bing  , Yu Zhi-Wei  , Huang Huo-Gen  , Jiang Nan  , Dong Chuang  ,   (1)大连海事大学金属材料工艺研究所，大连  116024; (2)大连理工大学材料工程系，大连  116024; (3)大连理工大学材料工程系，大连  116024;大连理工大学三束表面改性国家重点实验室，大连  116024
Published: December 2020

At the composition of Ti4040Zr4040Ni2020 , a single_phase cylindr ical quasicrystalline alloy, 3mm in diameter and 15mm in length, can be fabr icated by a copper-mold casting method. Its quasicrystalline nature and structu ral homogeneity were confirmed by x_ray diffraction and transmission electron mi croscopy. According to compression and indentation tests at room_temperature, th e as_cast Ti4040Zr4040Ni2020 quasicry stalline rod has a hardness of 55GPa and a fracture strength of 542MPa. In particular, the Young's modulus (～43GPa) of Ti404Zr4040 Ni2020 quasicrystals is consid erably low while they possess a high Poisson's ratio (～048). Under monax ial compression, the Ti4040Zr4040Ni2020 quasicrystalline alloy e xhibits a highly elastic deformation capability of 125%. The cleavage fracture morphologies indicate a brittle fracture mechanism.
Absorption measurements of ambient methane with tunable diode laser
Authors: Kan Rui-Feng  , Liu Wen-Qing  , Zhang Yu-Jun  , Liu Jian-Guo  , Dong Feng-Zhong  , Gao Shan-Hu  , Wang Min  , Chen Jun  ,   中国科学院安徽光学精密机械研究所,合肥  230031
Published: December 2020

Tunable diode laser absorption spectroscopy (TDLAS) is a new trace gas detective method developed with the combination of a diode laser source and a long absorption path. It has the significant advantage not only in sensitivity but also in rapidity of response. The concentration of the ambient methane has been measured using a TDLAS system developed in the laboratory. The system has some advantage s, such as sensitivity, low detective limit (below 0.087mg/m33) an d rapidity of response, and also it is easy to be integrated to a portable apparatus to mon itor the methane concentration in the atmosphere.
The Hamiltonian theory of Landau-Lifschitz equation and the gauge transformations
Authors: He Jin-Chun  , Shi Li-Na  , Chen Hua  , Huang Nian-Ning  ,   (1)武汉大学数学与统计学院，武汉  430072; (2)武汉大学物理学院，武汉  430072
Published: December 2020

The coordinate and spectral integral representations of Hamiltonian in isotropic LandauLifschitz equation are given by a standard procedure.But,the problem of deriving the corresponding conserved quantity to connect two kinds of integral mentioned above is still open.In this paper,using the gauge invariance properties,the compatibility pair of LL equation is transformed to the form-ikσ3+O(1) by choosing an app ropriate tr ansformation.Hence,the conserved quantities are obtained.The zeroth conserved qu antity,I0,is zero.The first one,I1,which has coordinate an d spe ctral integral representations,coincide with the two desired integral representations of the Hamiltonian.
Generation of axial line-focus using a binary-phase Fresnel zone plate
Authors: Li Yu-Tong  , Zhang Jie  , Lu Xin  , Jin Zhan  , Pepler D. A.  , Danson C. N.  ,   (1)CLRC Rutherford Appleton Laboratory,Chilton,Didcot,OXON,OX11 0QX. UK; (2)中国科学院物理研究所光物理实验室,北京  100080
Published: December 2020

In this paper, a uniform axial line_focus, which is important for the x_ray lase r amplification pumped by picosecond and femtosecond laser pulses, is generated by a binary_phase Fresnel zone plate. The performances of the plate are tested u sing a ultrashort_pulse laser. The results show that the length and the width of the line_focus are ～5mm and ～100μm respectively, when coupled with a 125mm f ocal length lens. The ratio of the peak intensity at the center of the line focu s to the intensity outside around the line focus is 7:1
Study of SH acoustic radiation field excited by a piezoelectric strip
Authors: Zhang Bi-Xing  , Wang Cheng-Hao  , Bostr?m Anders  ,   (1)瑞典Chalmers工业大学应用力学系,哥德堡  SE-412 96; (2)中国科学院声学研究所,北京  100080
Published: December 2020

A piezoelectric strip of infinite length but with finite width and thickness is placed on top of an isotropic elastic half space. The piezoelectric strip is excited by an electrical signal and the acoustic field is generated. The piezoelectric strip is of type 6mm crystal system oriented along its length direction. The SH wave is studied for the structure of this piezoelectric transducer. At first, the field is expanded as a Fourier series in the piezoelectric strip and as a Fourier integral in the half space. Then, the response of the solution inside the piezoelectric strip and in the half space is obtained by the boundary conditions. The acoustic field distribution is analyzed and compared to that obtained by the traditional method. Finally, the acoustic radiation field at the far field is investigated by the saddle point method and the directional factor is analyzed. It is found that the traditional method is valid only in the case where the product of the frequency with the width of the piezoelectric strip is less than1kHz·m. The stress and displacement in the piezoelectric strip are oscillatory distributions when the frequency increases. The greater the frequency, the greater the difference between the traditional method and the present method.
The microstructure of hydrogenated microcrystalline silicon thin films studied by small-angle x-ray scattering
Authors: Zhou Bing-Qing  , Liu Feng-Zhen  , Zhu Mei-Fang  , Gu Jin-Hua  , Zhou Yu-Qin  , Liu Jin-Long  , Dong Bao-Zhong  , Li Guo-Hua  , Ding Kun  ,   (1)中国科学院半导体研究所，北京  100083; (2)中国科学院高能物理研究所北京同步辐射实验室，北京  100039; (3)中国科学院研究生院物理系，北京  100039; (4)中国科学院研究生院物理系，北京  100039;内蒙古师范大学物理系，呼和浩特  010022
Published: December 2020

The microstructures of hydrogenated microcrystalline silicon (μc-Si:H) thin fil ms, prepared by plasma-enhanced chemical vapor deposition (PECVD), hot wire CVD( HWCVD) and plasma assisted HWCVD (PE-HWCVD), have been analyzed by the small ang le x_ray scattering(SAXS) measurement. The SAXS data show that the microstructur es of the μc-Si:H films display different characteristics for different deposit ion techniques. For films deposited by PECVD, the volume fraction of micro-voids and mean size are smaller than those in HWCVD sample. Aided by suitable ion-bom bardment, PE-HWCVD samples show a more compact structure than the HWCVD sample. The microstructure parameters of the μc-Si:H thin films deposited by two-steps HWCVD and PE-HWCVD with Ar ions are evidently improved. The result of 45° tilti ng SAXS measurement indicates that the distribution of micro-voids in the film i s anisotropic. The Fouriertransform infrared spectra confirm the SAXS data.
Determination of fractal dimensions of silicon dioxide xerogel by means of gas-adsorption
Authors: Sheng Yong-Gang  , Xu Yao  , Li Zhi-Hong  , Wu Dong  , Sun Yu-Han  , Wu Zhong-Hua  ,   (1)中国科学院高能物理研究所同步辐射实验室，北京  100039; (2)中国科学院山西煤炭化学研究所煤转化国家重点实验室，太原  030001; (3)中国科学院山西煤炭化学研究所煤转化国家重点实验室，太原  030001;中国科学院研究生院，北京  100039
Published: December 2020

Analysis of the structure of most irregular porous materials has recently been developed on the basis of the concepts of fractal geometry. The geometry enables general statements about so-called irregular structures to be made in terms of a few well-defined mathematical ideas, e.g. self-similarity and scaling, and a few mathematical parameters, e.g. fractal dimension. Gas adsorption is an ideal tool for characterization of the pore structure of xerogels and other porous materials. In this short paper, a simple and effective method to determine the fractal dimension of xerogels is presented. Instead of carrying out a series of gas adsorption/desorption experiments with various gases, only one gas adsorption/desorption experiment using a kind of gas is needed here. By studying the relations between the scaling and the data of pore size distribution and specific surface area, both surface fractal dimension and pore distribution fractal dimension can be easily derived. The reliability of the results is realized by performing error analysis and correction. The effectivity of the method is tested by experimental N2 adsorption/desorption data of silica xerogels prepared with sol-gel routine.
FTIR study an VO2 defect in fast neutron irradiated Czochralski silicon
Authors: Yang Shuai  , Li Yang-Xian  , Ma Qiao-Yun  , Xu Xue-Wen  , Niu Ping-Juan  , Li Yong-Zhang  , Niu Sheng-Li  , Li Hong-Tao  ,   (1)河北工业大学材料科学与工程学院，天津  300130; (2)天津工业大学信息与通信学院，天津  300160; (3)中国原子能科学研究院，北京  102413
Published: December 2020

The vacancy_dioxygen complex(VO2) is one of the main defects formed i n fast neutron irradiated CZ_Si during annealing in the temperature range 400—500℃. In this defect,two oxygen atoms share a vacancy,each of which is bonded to two s ilicon neighbors.With the increase of the 889cm-1(VO2),two infrared absorption bands at 919.6 and 1006cm-1 will arise in neutron irradia ted CZ _Si after annealed in the temperature range 300—500℃.IR vibrational bands at 9 19.6 and 1006cm-1 can be assigned to the metastable defect (O-V-O)th at is composed of a VO(A center) and a neighboring interstitial oxygen(Oi)atom.By prolonging the annealing time from 2h up to 10h or increasing the annealing temperature,the metastable defect(O-V-O)will be converted into V O2.During annealing in the temperature range 400—500℃,the main defe cts for med in the high dose(1019) neutron irradiated CZ_Si is the multi_vac ancy type of defects and the formation of the VO2 will be depressed.
Spontaneous magnetostriction of Tb2Fe15.5Cr1.5 compound
Authors: Hao Yan-Ming  , Zhou Yan  , Zhao Miao  ,   (1)天津师范大学物理与电子信息学院，天津  300074; (2)天津师范大学物理与电子信息学院，天津 300074
Published: December 2020

The negative thermal expansion and spontaneous magnetostrictive deformation of Tb2Fe15.5Cr1.5 compound have been investigated by means of x-ray diffraction and magnetization measurements. The compound Tb2Fe15.5Cr1.5 has a hexagonal Th2Ni17-type structure from 293 to 672K. A negative thermal expansion was fou nd from 432 to 522K. The coefficient of the average thermal expansion is =-157 ×10-5/K. There exists a strong and anisotropic spontaneous magnetost riction in the magnetic state of Tb2Fe15.5Cr1.5 . The spontaneous volumetric magnetostrictive deformation is about 84×10-3 at 293K and the deformation occurs mainly in the directi on of c-axis. The result of magnetization measurement shows that the Curie tempera ture of Tb2Fe15.5Cr1.5 is 494K, which is by abo ut 80K higher than the mother compound Tb2Fe17.
A multiple input-queued ATM switching fabric based on hopfield neural network cell scheduling
Authors: Xiong Tao  , Zhang Bian-Li  , Chang Sheng-Jiang  , Shen Jin-Yuan  , Zhang Yan-Xin  ,   (1)南开大学现代光学研究所,教育部光电信息技术重点实验室,天津  300071; (2)南开大学现代光学研究所,教育部光电信息技术重点实验室,天津  300071;郑州大学,河南省激光与光电信息技术重点实验室,郑州  450052
Published: December 2020

A multiple input-queued ATM switching fabrics (ASF) for scheduling cell based on Hopfield neural network (HNN) is proposed. This scheme eliminates degeneration of performance due to head-of-line (HOL) blocking. Simulation results show that, compared with the single first in_first out and window input-queued ASF, the pr oposed approach can greatly improve the throughput and reduce the cell delay.
Investigation on the time series of ice core and stalagmite based on the analysis of complexity
Authors: Hou Wei  , Feng Guo-Lin  , Gao Xin-Quan  , Chou Ji-Fan  ,   (1)国家气候中心气候研究开放实验室，北京  100081;中国科学院大气物理研究所,北京  100029; (2)兰州大学大气科学系,兰州  730000; (3)扬州大学物理科学与技术学院,扬州  225009
Published: December 2020

The complexity series of the Guliya (Tibetan plateau) ice core and Shihua cave (Beijing) stalagmite proxy records were respectively calculated in this paper, using a dynamical nonlinear analysis method for time series-Lemper-Ziv complexityalgorithm; and the physical implication of Lemper-Ziv complexity and its meaning in the study of climate change were also discussed. The wavelet analysis resul ts show that there exist distinctive quasi-periods of 780_, 380_, 160_, and 105_ year in the complexity series. Further investigations indicate that when differ ent window lengths are selected, the characters of the complexity series for a g iven time series are basically the same, and there exists the coherency between the jumps of the complexity series and the climatic jumps on various timescales . This paper presents, for the first time so far as we know, the oscillation on 380_year timescale in the recent millennium, with amplitude decaying and intri nsic period reducing. The complexity of the time series has gradually reduced si nce 1900. For the complexity of the stalagmite data,there has been the quasi-equ al-amplitude oscillation after 1920, which is similar to the circumstances of th e warming epochs over China in the middle of the sixth century and the middle o f the twelfth century. Consequently, the reason for the warming in the twentiet h century remains to be necessary to study.
Beltrami-de Sitter spacetime and de Sitter invariant special relativity
Authors: Guo Han-Ying  , Huang Chao-Guang  , Tian Yu  , Xu Zhan  , Zhou Bin  ,   (1)清华大学物理系和高等研究中心,北京  100084; (2)中国科学院高能物理研究所，北京  100049;中国科学院理论物理研究所，北京  100080; (3)中国科学院理论物理研究所，北京  100080
Published: December 2020

The puzzle on the relation between principle of special relativity and cosmologi cal principle, as well as the Beltrami-de Sitter-Lu puzzle on de Sitter/anti-de Sitter spacetimes in Einstein's framework of relativity are analyzed. It i s possible to generalize the principle of special relativity to the spacetimes w ith constant curvature and to establish the kinematics and particle dynamics for the special relativity in de Sitter/anti-de Sitter spacetimes with Beltrami met ric. In such a Beltrami system by the Beltrami coordinate simultaneity is just a n inertial system, the corresponding observers are inertial observers, the inert ial law is valid for test particles and light signals, and observables can be we ll defined which conserve and satisfy the generalized Einstein's formula. In addition to the Beltrami coordinate simultaneity there is also the proper-time simultaneity for the comoving observations and thus the Beltrami metric is trans formed into the Robertson-Walker-like metric which gives a closed 3-dimensional space and its deviation from flatness is of the order of cosmological constant. Therefore, it turns out that in such a kind of special relativity the relativity principle has an intrinsic affiliation with the “perfect” cosmological princi ple and without any puzzle. Furthermore, based on the recent astronomical observ ations, the Mach's principle is restated and it is showed that the cosmologi cal constant acts just as an origin of inertial motions in the de Sitter-invaria nt special relativity on Beltrami-de Sitter spacetime.
Bound states solutions of the Klein-Gordon equation with Hartmann potential and recursion relations
Authors: Chen Zi-Dong  , Chen Gang  ,   绍兴文理学院物理系，绍兴  312000
Published: December 2020

The bound state solutions of the Klein_Gordon equation are obtained.When Hartman n_type scalar and vector potentials are equal. It is shown that the radial and a ngular wave functions are respectively expressed by confluent hypergeogetric an d hypergeogetric functions. In addition, two kinds of recursion relations of ra dial wave functions for given ‘principal' and ‘angular-momentum' quantum numb ers are also derived.
Phase-field modeling of isothermal solidification in binary alloy
Authors: Long Wen-Yuan  , Cai Qi-Zhou  , Chen Li-Liang  , Wei Bo-Kang  ,   (1)华中科技大学材料科学与工程学院模具技术国家重点实验室,武汉  430074; (2)华中科技大学材料科学与工程学院模具技术国家重点实验室,武汉  430074;南昌航空工业学院材料科学与工程系,南昌  330034
Published: December 2020

A new phase-field model is developed based on the Ginzberg-Landau theory, which is consistent with WBM model and KKS model. The dendritic growth process during the solidification in a Al-65%Cu binary alloy was simulated using the phase-field model. Solute diffusion equation was solved simultaneously. The effects of undercooling on the dendritic growth and solute profile in isothermal solidification of binary alloy were investigated. The results indicate that the dendritic has well-developed secondary arms with the increase of undercooling. Correspondently, the solute Peclet number and the tip speed increases, the tip radius decreases, and the solute segregation in solid-liquid interface increases. The results agree well with Ivantsov theory.
Computer simulation for ramified aggregates on nonlattice substrates with impurities
Authors: Gao Guo-Liang  , Qian Chang-Ji  , Li Hong  , Huang Xiao-Hong  , Gu Wen-Jing  , Ye Gao-Xiang  ,   (1)温州大学物理系，温州  325035; (2)温州大学信息学院，温州  325035; (3)浙江大学物理系，杭州  310028
Published: December 2020

According to the experimental results of Au atomic aggregaties on molten glass surfaces with impurities, based on the characteristic assumption that clusters diffuse with random diffusion steps and rigid rotation angles, an improved restri cted cluster_cluster aggregation model for nonlattice substrates with impurities is established. Then the whole diffusion，rotation and aggregation processes of the clusters are simulated. The impurities are distributed on the nonlattice su bstrate ramdomly, and its influence on the properties of the ramified aggregates is studied systematically .The simulation data are in good agreement with the e xperimental results.
Fractional spin in non-Abel Chern-Simons theories
Authors: Zhang Ying  , Li Zi-Ping  ,   北京工业大学应用数理学院，北京  100022
Published: December 2020

The property of fractional spin of O(3) non-linear sigma model with non-Abel Chern-Simons term at the quantum level is studied. This formulation is differen t from the classical theories. According to the rule of path integral quantizati on for a constrained Hamiltonian system in Faddeev-Senjanovic scheme，the system is quantized. Based on the quantal Noether theorem，the quantal conserved angu lar momentum is obtained and the fractional spin at the quantum level of this sy stem is presented.
Electromagnetic modes of thickness-modulated dual-periodic one-dimensional photonic crystals
Authors: Zhou Jin-Gou  , Du Gui-Qiang  , Zhang Ya-Wen  , Liu Nian-Hua  ,   (1)哈尔滨工业大学威海校区应用物理系,威海  264209; (2)哈尔滨工业大学威海校区应用物理系,威海  264209;南昌大学物理系, 南昌  330047; (3)井冈山学院物理系, 吉安  343009;南昌大学物理系, 南昌  330047; (4)南昌大学物理系, 南昌  330047
Published: December 2020

We have studied the photonic band of dual_periodic one_dimensional(1D) photonic crystals. The band splits into many sub_bands when we modulate periodically the thickness of the unit of the 1D photonic crystal. Some narrow bands appear in th e gap of the simple photonic crystal with single_period. The field of the electr omagnetic modes in the split bands exhibits dual_periodicity. The modes in the n arrow bands are localized, but those in the wider bands are extended.
Experimental study of femtosecond Ti:sapphire laser with low-threshold pump
Authors: Ling Wei-Jun  , Wei Zhi-Yi  , Sun Jing-Hua  , Wang Zhao-Hua  , Tian Jin-Rong  , Jia Yu-Lei  , Wang Peng  , Han Hai-Nian  ,   中国科学院物理研究所光物理重点实验室，北京  100080
Published: December 2020

A low-threshold self-starting Kerr-lens mode-locked Ti:sapphire laser was demons trated by use of a tight focusing cavity design and a semiconductor saturable-ab sorber mirror (SESAM). With a 3% and a 12% output couplers, we achieved mode-loc king thresholds as low as 390 and 600mW, respectively. Stable femtosecond laser pulses with average power of 114mW were generated for pump power at 12W, which corresponds to a typical duration of 17fs and bandwidth of 47nm. The pump power range for mode-locking covers from 600 mW to 48W at a 12% output coupler, an d the mode-locking stability is improved.
Buckling of a single wall carbon nanotube under an axial pressure based on the nonlocal elastic theory
Authors: Xie Gen-Quan  , Han Xu  , Long Shu-Yao  , Tian Jian-Hui  ,   (1)湖南大学工程力学系，长沙  410082; (2)湖南大学工程力学系，长沙  410082;现代车身技术教育部重点实验室，湖南大学，长沙  410082; (3)现代车身技术教育部重点实验室，湖南大学，长沙  410082
Published: December 2020

A shallow shell model is developed for the elastic buckling of a single wall car bon nanotube under a uniform external axial pressure by using the nonlocal elastic theory. Effects of the small size scale are incorporated in the formulation Critical conditions are given under the axial buckling pressure for a single-w all carbon nanotube. Influences of the small size scale on the axial buckling pr essure are found. It is concluded that the axial buckling pressure for a carbon nanotube could be overestimated by the classic shell model without considering t he effect of the small size scale.
Raman study of SnO2 nanograins under different annealing temperature
Authors: Ding Shuo  , Liu Yu-Long  , G. G. Siu  ,   (1)香港城市大学物理与材料科学系,中国香港）; (2)中国科学院物理研究所,北京  100080
Published: December 2020

SnO２ nano-crystalline grains with sizes in the range of 4—80 nm ar e systematically investigated using Raman spectroscopy. Besides SnO２ fundam ental-fre quency modes, a few weak Raman modes and a very strong and broad photoluminescen ce peak at about 700 nm can be observed. Our results show that bulk properties o f nano-SnO２ diminish but the defect-, surface-, and size-related fea tures dis play as grain size decreases. A critical size that divides respective predominan ce is determined to be about 20 nm. Bulk spectra with spectroscopic line broaden ing and position shifting, a surface mode and interface mode around 571 cm －１and 351 cm－１, as well as the O-H vibration modes of the water mol ecu les in SnO２ nanograins are characteristics of Raman spectra of nano- SnO２ with grain size below 20 nm. They are related to the microstructure change of the nanograins, i.e. they reflect the change of grain size, surface, and the in teraction between nanograins.
Hojman’s conservation theorems for Raitzin’s canonical equations of motion of nonlinear nonholonomic systems
Authors: Qiao Yong-Fen  , Li Ren-Jie  , Sun Dan-Na  ,   (1)莱阳农学院基础部，莱阳市  265204; (2)浙江理工大学机械工程与自动化系，杭州  310027;莱阳农学院基础部，莱阳市  265204;东北农业大学工程学院，哈尔滨  150030
Published: December 2020

Using the Lie symmetry under infinitesimal transformations in which the time is not variable, the Hojman's conservation theorems for Raitzin's canonical equations of motion of nonlinear nonholonomic systems are studied. The differential equations of the systems and the determining equations of Lie symmetry under infinitesimal transformations are given. The Hojman's conservation theorems of the systems are established. Finally, we give an example to illustrate the application of the result.
The contribution of the high spinning gravitation field to the static black hole entropy with spherical-symmetry
Authors: Su Jiu-Qing  , Li Chuan-An  ,   菏泽学院物理系，菏泽  274015
Published: December 2020

Using the improved brickwall model,the writers of the article have made some researches in the contribution made by the high spinning gravitation field to static ballsymmetry black hole entropy. The research shows that in the static ballsymmetry black hole, the quanta entropy of the gravitation field in whitch the spinning is 2 is still in direct proportion to the horizon. When the same truncatin genes as theose in scalar guantity field are selected the quanta entropy is two times in scalar quantity field, and foursevenths of those in Dirac field.
Information theory approach to determine embedding parameters for phase space reconstruction of chaotic time series
Authors: Xiao Fang-Hong  , Yan Gui-Rong  , Han Yu-Hang  ,   (1)西安交通大学建筑工程与力学学院，西安  710049; (2)中国工程物理研究院，绵阳  610003
Published: December 2020

We have studied the determination of delay time and embedding dimension for phase space reconstruction of chaotic time series using the information theory. We use the symbolic analysis method to compute mutual information for determining the delay time. Furthermore we also present an information theory approach to determine embedding dimension. That is, we determine the embedding dimension by considering the variation of the conditional entropy of the reconstructed vector with its dimension. Numerical simulations verify that the method is applicable for determining an appropriate embedding dimension.
Experimental study on explosion mechanism of large agron clusters in intense laser pulses
Authors: Li Shao-Hui  , Wang Cheng  , Liu Jian-Sheng  , Wang Xiang-Xin  , Li Ru-Xin  , Ni Guo-Quan  , Xu Zhi-Zhan  ,   (1)中国科学院上海光学与精密机械研究所强光实验室,上海  201800; (2)中国科学院上海光学与精密机械研究所强光实验室,上海  201800;汕头大学物理系,汕头  515063
Published: December 2020

By using timeofflight spectroscopy, the ionization and explosion of large argon clusters (n—=3×103-3×106) in the intense femtosecond pulsed lase r field (60 fs，2×1016 W/cm2) has been studied, and the dependence of a verage energy of ions emitted from argon clusters on the gas backing pressure ha s been measured. By comparing the average ion energies obtained with two differe nt supersonic conical nozzles and considering the Hagena's scaling law of clust ers, we have found that the average ion energy is determined by the cluster size when the laser parameters are kept unchanged. The experimental results indicate d that when the cluster size is less than 3×105 atoms per cluster, the Coulom b repulsion force is the dominating factor in the expansion mechanism. Beyond th is size, for 3×105<n—<3×106, the expansion is the result of the combi ned effect of both the Coulomb repulsion force and the hydrodynamic force, and t he latter will play the dominating role for increasing cluster size.
Modeling of refraction and saturation effects of x-ray lasers
Authors: Yan Fei  , Zhang Jie  , Lu Xin  ,   中国科学院物理研究所光物理重点实验室,北京  100080
Published: December 2020

The propagation of a Ni_like Ag x_ray laser operating at 139 nm is numerically simulated. A two_dimensional ray tracing code is used to investigate the refraction and saturation effects of the x_ray laser beam as a postprocessor of a one_dimensional hydrodynamic code. The x_ray laser beam trajectory in a plasma medium and the spatially integrated laser output intensity as functions of the plasma length are calculated. Numerical results show that the refraction effect plays an important role in the beam propagation and amplification process.
The x-ray spectra of hollow atoms
Authors: Zhao Yong-Tao  , Xiao Guo-Qing  , Zhang Xiao-An  , Yang Zhi-Hu  , Chen Xi-Meng  , Li Fu-Li  , Zhang Yan-Ping  , Zhang Hong-Qiang  , Cui Ying  , Shao Jian-Xiong  , Xu Xu  ,   (1)兰州大学物理学院，兰州  730000; (2)西安交通大学应用物理系，西安  710049; (3)中国科学院近代物理研究所，兰州  730000; (4)中国科学院近代物理研究所，兰州  730000;西安交通大学应用物理系，西安  710049
Published: December 2020

The x-ray spectra of hollow atoms in the interaction of highly charged argon ions with beryllium solid surface are reported. The interaction ions, provided by t he electron cyclotron resonance (ECR) ion source in the National Laboratory of t he Heavy Ion Research Facility in Lanzhou(HIRFL), include bare argon ions, which are produced by the ion source for the first time, and hydrogen-like, helium-li ke and lithium-like argon ions. We found that the K-shell x-ray yield of single particles in the interaction of hydrogen-like argon ions is 36×10-3, wh ich is 5 orders more than that of helium-like argon ions, and the K-shell x-ray cannot be measured in the interaction of lithium-like argon ions with beryllium surface.
Ab inition studies on the electric and optical properties of Rb2TeW3O12
Authors: Zhang Yong  , Tang Chao-Qun  , Dai Jun  ,   华中科技大学物理系，武汉  430074
Published: December 2020

By using the plane_wave ultrasoft pseudopotential method, the geometric parameters, electric and optical properties of Rb2TeW3O12 are investigated. The equilibrium lattice constants are in good agreement with experimental data. The electric structures reveal that Rb2TeW3O12 is a direct wide_band semiconductor and the band gap is 223eV; W 5d and O 2p states form a strong W— O covalent bond. Optical properties have been studied and we have presented the dielectronic functions ε1 and ε2. Static dielectric constant　ε 0=529 have been gained.
Ultrahigh piezoelectric response along some special cleavage plane in BaTiO3 single-crystals
Authors: Chu Rui-Qing  , Xu Zhi-Jun  , Li Guo-Rong  , Zeng Hua-Rong  , Yu Han-Feng  , Shao Xin  , Luo Hao-Su  , Yin Qing-Rui  ,   (1)聊城大学材料科学与工程学院，聊城  252059; (2)中国科学院上海硅酸盐研究所高性能陶瓷和超微结构国家重点实验室，上海  200050; (3)中国科学院上海硅酸盐研究所高性能陶瓷和超微结构国家重点实验室，上海  200050;聊城大学材料科学与工程学院，聊城  252059
Published: December 2020

Ultrahigh piezoelectric response along easy cleavage plane in BaTiO3 singl e_crystal was found. An extremely high value of piezoelectric coefficient d 33 value over 2000 pC/N was obtained after being poled perpendicular to th is plane of BaTiO3 crystal, which is more than 20 times higher than those poled along spontaneous polarization direction 〈001〉 (d33〈001〉=87p C/N). A large strain of 06% was obtained at a very low electric field. The res ults may generate a wide range of lead_free materials for the piezoelectric tran sducer application.
A field method for solving Whittaker equations
Authors: Ge Wei-Kuan  ,   湖州师范学院物理系，湖州  313000
Published: December 2020

We present a field method for solving the Whittaker equations.One of the field variables is considered as a function of other variables and time,and the fundamental partial differential equation for the function is established.If the complete integral of the partial differential equation can be obtained,the solution of the Whittaker equations are obtained by solving the algebraic equations.
Effect of polarization of THz pulse and probe pulse on THz electro-optic detection
Authors: Zheng Guo-Liang  , She Wei-Long  ,   中山大学光电材料与技术国家重点实验室，广州  510275
Published: December 2020

We studied the effect of polarization of terahertz pulse and probe beam on terahertz detection in optically isotropic detection crystals using wave coupling theory of linear electro-optic effect. The study results show that the effect is remarkable, and the detection can get its largest sensitivity when the probe beam propagates along (110) direction which is most suitable for terahertz detection. Some of the study results are in good agreement with the previously published experimental results. So our study is helpful for the design of electro-optic detectors.
Numerical calculation of multiple scattering of high frequency electromagnetic wave
Authors: Li Yun-Zhou  , Shi Qing-Fan  , Wang Qi  ,   (1)北京理工大学物理系，北京  100081; (2)盐城师范学院计算机系，盐城  224002
Published: December 2020

Using physical optics to calculate single scattering, and using equivalent ray tubes to calculate multiple scattering, we can get the numerical results more efficiently and accurately. Several complex perfect electric conductors and medium targets are calculated, and numerical results are in good agreement with experiments.
Real-time determination of plasma confinement parameters in HL-2A
Authors: Yuan Bao-Shan  , You Tian-Xue  , Qin Yun-Wen  , Feng Bei-Bin  , Ji Xiao-Quan  ,   核工业西南物理研究院，成都  610041
Published: December 2020

During the plasma discharge in HL-2A, the magnetic field at the plasma boundary is computed using currents filaments code. The Shafranov integrals S1，S2 and S3 are deduced; the poloidal beta, internal inductance, the horizontal position of the magnetic axis Rm and the plasma energy Wdia are calculated; the current center of plasma (Rc,Zc)is computed with the current moments. The real time determination of these quantities is of significance for understanding and adjusting the HL-2A discharge in time, and for improving plasma performance.
The grain boundary segregation of microalloying elements and the ultra-refinement of steel
Authors: Zhang Guo-Ying  , Zhang Hui  , Liu Chun-Ming  , Zhou Yong-Jun  ,   (1)东北大学材料冶金学院，沈阳  110004; (2)沈阳师范大学物理科学与技术学院，沈阳  110034; (3)沈阳师范大学物理科学与技术学院，沈阳  110034;东北大学材料冶金学院，沈阳  110004
Published: December 2020

A model of Σ5〈001〉/(210) high angle grain boundary (GB) in austenite phase in steel was set up with computer programming. The environment-sensitive embedding energies (ESE) of C, N and microalloying elements in grains or in GB core are c alculated by recursion method, respectively. The segregation and interaction of C, N and microalloying elements in the GB core were discussed. Calculation resul ts show that: discrete light impurities C and N tend to segregate in the GB area , forming atomic clusters; microalloying elements are liable to distribute in pe rfect austenite grains. Ti, V, Nb occupy the top sites of the trigonal prism for med by iron in the GB core, and Ti, V, Nb can also form atomic clusters in GB co re like C or N. When the temperature is decreased and the concentration of C, N and microalloying elements reach to the limit of solubility, the C, N compounds of microalloying elements precipitate from the matrix in GB core of austenite in steel. These compounds can act as heterogeneous nuclei of austenite phase in th e course of recrystallization and retard the growth of austenite grains, leading to the refinement of austenite grains. Nb is the most efficient refiner of micr oalloying elements Nb, Ti, V.
Effect of radiation trapping on spectroscopic properties of Er3+-doped oxide glasses
Authors: Dai Shi-Xun  , Xu Tie-Feng  , Nie Qiu-Hua  , Shen Xiang  , Zhang Jun-Jie  , Hu Li-Li  ,   (1)宁波大学信息科学与工程学院，宁波  315211; (2)宁波大学信息科学与工程学院，宁波  315211;中国科学院上海光学精密机械研究所，上海  201800; (3)中国科学院上海光学精密机械研究所，上海  201800
Published: December 2020

The absorption spectra, fluorescence spectra and the lifetimes of 4I13/2 level of Er3+-doped phosphate and tellurite glasses ha ve been measured for sample with different concentrations and thickness. The abs orption cross-section (σa), emission cross-section(σe), spontaneous emission probability(Arad), radiative lifetime(τrad ) and quantum efficiency(η) of fluorescence around 1.53 μm of Er3+-doped phosphate and tellurite glasses were determined. The effect of radia tion trapping on the spectral properties and parameters of Er3+-doped tellurite and phosphate glasses has been investigated. It was found that radiat ion trapping exists generally in erbium-doped glass hosts, even at low Er3+ -doping concentration (0.1 mol% Er2O3). Due to radia tion trapping, the values of the τrad of the Er3+∶4 I13/2 level in tellurite glasses increased about 11%—37％ with the sample thickness and erbium doping concentration, while in phosphate glasse s τrad increased by 6%—17%. The full-width at half maximum (FWHM)of fluorescence in tellurite glasses increased about 15%—64%, with 11%—55% for p hosphate glasses. It caused a high overestimation on the figure of merits (FOM) for amplifier bandwidth (σe×FWHM). The spectral overlap between the emission and absorption spectra in 1.53 μm band is relatively larger in tellur ite than in phosphate glasses, and values of the emission cross-section in tellu rite glasses are larger than that in phosphate glasses. Consequently, the radiat ion trapping in tellurite glasses is more severel than that in phosphate glasses .