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Evaluation of the effects of EPS composite soil replacement on the dynamic performance of caisson structure using shaking table tests
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作者 Gao Hongmei Ji Zhanpeng +3 位作者 Zhang Xinlei Zhang Shushan Wang Zhihua Shen Guangming 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2024年第4期829-843,共15页
The seismic performance of a caisson structure under two types of models with a saturated sandy foundation(CSS)and an expanded polystyrene(EPS)composite soil foundation(CES)are studied using shaking table tests.The ma... The seismic performance of a caisson structure under two types of models with a saturated sandy foundation(CSS)and an expanded polystyrene(EPS)composite soil foundation(CES)are studied using shaking table tests.The macro phenomena of the two different foundation models are described and analyzed.The effects of the replacement of EPS composite soil on seismic-induced liquefaction of backfill and the dynamic performance of a caisson structure are evaluated in detail.The results show that the excess pore water pressure generation in the CES is significantly slower than that in the CSS during the shaking.The dynamic earth pressure acting on the caisson has a triangular shape.The response of horizontal acceleration,displacement,settlement,and rotation angle of the caisson in the CES is smaller than that in the CSS,which means the caisson in the CES has a better seismic performance.Furthermore,the out-of-phase phenomenon between dynamic earth thrust and inertial force in the CES is more obvious than that in the CSS,which is beneficial to reduce the lateral force and improve the stability of the caisson structure. 展开更多
关键词 EPS composite soil foundation Caisson-type quay wall shaking table test phase difference rotation angle
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Numerical storm surge model with higher order finite difference method of lines for the coast of Bangladesh 被引量:2
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作者 Gour Chandra Paul Md. Emran Ali 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2019年第6期100-116,共17页
In this study, the method of lines (MOLs) with higher order central difference approximation method coupled with the classical fourth order Runge-Kutta (RK(4,4)) method is used in solving shallow water equations (SWEs... In this study, the method of lines (MOLs) with higher order central difference approximation method coupled with the classical fourth order Runge-Kutta (RK(4,4)) method is used in solving shallow water equations (SWEs) in Cartesian coordinates to foresee water levels associated with a storm accurately along the coast of Bangladesh. In doing so, the partial derivatives of the SWEs with respect to the space variables were discretized with 5-point central difference, as a test case, to obtain a system of ordinary differential equations with time as an independent variable for every spatial grid point, which with initial conditions were solved by the RK(4,4) method. The complex land-sea interface and bottom topographic details were incorporated closely using nested schemes. The coastal and island boundaries were rectangularized through proper stair step representation, and the storing positions of the scalar and momentum variables were specified according to the rules of structured C-grid. A stable tidal regime was made over the model domain considering the effect of the major tidal constituent, M2 along the southern open boundary of the outermost parent scheme. The Meghna River fresh water discharge was taken into account for the inner most child scheme. To take into account the dynamic interaction of tide and surge, the generated tidal regime was introduced as the initial state of the sea, and the surge was then made to come over it through computer simulation. Numerical experiments were performed with the cyclone April 1991 to simulate water levels due to tide, surge, and their interaction at different stations along the coast of Bangladesh. Our computed results were found to compare reasonable well with the limited observed data obtained from Bangladesh Inland Water Transport Authority (BIWTA) and were found to be better in comparison with the results obtained through the regular finite difference method and the 3-point central difference MOLs coupled with the RK(4,4) method with regard to the root mean square error values. 展开更多
关键词 SHALLOW water equations METHOD of lines higher order finite difference approximation METHOD SURGE nested scheme
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The Real-Time,High Precision Phase Difference Measurement of Electron Density in HL-2A Tokamak 被引量:1
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作者 丁宝钢 吴彤宇 +2 位作者 李世平 周艳 阴泽杰 《Plasma Science and Technology》 SCIE EI CAS CSCD 2015年第9期797-801,共5页
This paper introduces a real-time high precision measurement of phase difference based on Field Programmable Gate Array(FPGA) technology,which has been successfully applied to laser grating interference measurement ... This paper introduces a real-time high precision measurement of phase difference based on Field Programmable Gate Array(FPGA) technology,which has been successfully applied to laser grating interference measurement and real-time feedback of plasma electron density in HL-2A tokamak.It can track the changes of electron density while setting the starting point of the density curve to zero.In a laboratory test,the measuring accuracy of phase difference is less than 0.1°,the time resolution is 80 ns,and the feedback delay is 180 μs. 展开更多
关键词 phase difference HL-2A FPGA REAL-TIME high precision
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Optimization of the seismic processing phase-shift plus finite-difference migration operator based on a hybrid genetic and simulated annealing algorithm 被引量:2
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作者 Luo Renze Huang Yuanyi +2 位作者 Liang Xianghao Luo Jun Cao Ying 《Petroleum Science》 SCIE CAS CSCD 2013年第2期190-194,共5页
Although the phase-shift seismic processing method has characteristics of high accuracy, good stability, high efficiency, and high-dip imaging, it is not able to adapt to strong lateral velocity variation. To overcome... Although the phase-shift seismic processing method has characteristics of high accuracy, good stability, high efficiency, and high-dip imaging, it is not able to adapt to strong lateral velocity variation. To overcome this defect, a finite-difference method in the frequency-space domain is introduced in the migration process, because it can adapt to strong lateral velocity variation and the coefficient is optimized by a hybrid genetic and simulated annealing algorithm. The two measures improve the precision of the approximation dispersion equation. Thus, the imaging effect is improved for areas of high-dip structure and strong lateral velocity variation. The migration imaging of a 2-D SEG/EAGE salt dome model proves that a better imaging effect in these areas is achieved by optimized phase-shift migration operator plus a finite-difference method based on a hybrid genetic and simulated annealing algorithm. The method proposed in this paper is better than conventional methods in imaging of areas of high-dip angle and strong lateral velocity variation. 展开更多
关键词 Migration operator phase-shift plus finite-difference hybrid algorithm genetic andsimulated annealing algorithm optimization coefficient
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Construction of Solidus Lines of Binary Metal Systems Having a Low Solubility of Components in the Solid Phase
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作者 A. P. Shcherban O. A. Datsenko G. P. Kovtun 《Open Journal of Metal》 2014年第3期65-71,共7页
The paper presents the calculation results on the construction of solidus lines of phase diagrams for some binary metal systems based on cadmium, zinc and tellurium. The investigations have been carried out using the ... The paper presents the calculation results on the construction of solidus lines of phase diagrams for some binary metal systems based on cadmium, zinc and tellurium. The investigations have been carried out using the phase equilibrium thermodynamics and known liquidus lines. By the calculation method the solidus lines of phase diagrams of the Cd-Na, Cd-Tl, Te-Ga, Te-As, Te-Cu and Zn-Sn systems were constructed in the temperature range from the base component melting point to the eutectic transformation temperature. In the Cd-Tl, Te-As, Te-Cu and Zn-Sn systems a retrograde solubility of the second component in the solid phase was observed. The temperature and maximum solubility values at the retrograde behavior of solidus lines, as well as, the limiting solubility values of components at eutectic transformation in the systems based on Cd, Zn and Te were determined. 展开更多
关键词 BINARY METAL System Cadmium Zinc TELLURIUM phase Diagram SOLIDUS Line Eutectic Transformation RETROGRADE SOLUBILITY
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Optical simulation of in-plane-switching blue phase liquid crystal display using the finite-difference time-domain method 被引量:1
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作者 窦虎 马红梅 孙玉宝 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第9期117-121,共5页
The finite-difference time-domain method is used to simulate the optical characteristics of an in-plane switching blue phase liquid crystal display.Compared with the matrix optic methods and the refractive method,the ... The finite-difference time-domain method is used to simulate the optical characteristics of an in-plane switching blue phase liquid crystal display.Compared with the matrix optic methods and the refractive method,the finite-difference timedomain method,which is used to directly solve Maxwell's equations,can consider the lateral variation of the refractive index and obtain an accurate convergence effect.The simulation results show that e-rays and o-rays bend in different directions when the in-plane switching blue phase liquid crystal display is driven by the operating voltage.The finitedifference time-domain method should be used when the distribution of the liquid crystal in the liquid crystal display has a large lateral change. 展开更多
关键词 finite-difference time-domain method blue phase liquid crystal display in-plane switching convergence effect
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An Example of a Bounded Potential q(x) on the Half-Line, for Estimates of A(α) Amplitude
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作者 Herminio Blancarte 《Applied Mathematics》 2023年第2期130-149,共20页
We show an example of a bounded potential on the half-line obtained as the image of an Inverse Transformation Operator of the Bessel singular potential of the Reduced Radial Schr&#246;dinger Equation, and show us ... We show an example of a bounded potential on the half-line obtained as the image of an Inverse Transformation Operator of the Bessel singular potential of the Reduced Radial Schr&#246;dinger Equation, and show us the Estimates of the A(α) amplitude. 展开更多
关键词 the Amplitude A(α) as a Function of the phase α Estimates of the A(α) Amplitude A Bounded Potential on the Half Line
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On the Existence of a Minimum Universal Speed of Physical Transmissions Associated with Matter Wave in Special Relativity
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作者 Vu B. Ho 《Journal of Applied Mathematics and Physics》 2023年第5期1287-1303,共17页
In this work, we show that it is possible to establish coordinate transformations between inertial reference frames in the theory of special relativity with a minimum universal speed of physical transmissions. The est... In this work, we show that it is possible to establish coordinate transformations between inertial reference frames in the theory of special relativity with a minimum universal speed of physical transmissions. The established coordinate transformations, referred to as modified Lorentz transformations because they have almost identical form to the Lorentz transformations, also comply with the requirement of invariance of the Minkowski line element. Particularly, the minimum universal speed can be associated with the phase speed of de Broglie matter wave. As application, we also discuss the possibility to formulate relativistic classical and quantum mechanics for the special relativity associated with the modified Lorentz transformations, which describes physical processes that represent an expansion or a collapsing of massive quantum particles. 展开更多
关键词 Special Relativity Minkowski Line Element Minimum Universal Speed Modified Lorentz Transformations phase Velocity De Broglie Matter Wave Relativistic Mechanics
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THEORY OF BAINITIC TRANSFORMATION: A MODEL WITH COUPLED FIRST-ORDER PHASE TRANSFORMATIONS 被引量:1
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作者 Liu, X. Zhong, F. 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2000年第3期901-910,共10页
The Ginzbury-Landau theory for bainitic transformation was devised, which contains two first-order phase transformations, one being reconstructive represented by the diffusional proeutectoidal precipitation of ferrite... The Ginzbury-Landau theory for bainitic transformation was devised, which contains two first-order phase transformations, one being reconstructive represented by the diffusional proeutectoidal precipitation of ferrite, and the other the displacive transformation. It provides a coupled mechanism for the formation of bainite. With the numerical simulation results, a diffusion-induced nucleation and a diffusion-accompanied growth of displacive transformation were suggested. This theory can be helpful to over- throw the thermodynamic difficulty of displacive transformation above the Ms temperature, and also helpful to understand the Bs temperature, the partial supersaturation, the single variation of bainitic carbides, and the incomplete-reaction phenomenon of bainitic transformation, etc.. 展开更多
关键词 Bainitic transformations Computer simulation Crystalline materials Finite difference method Metallographic phases NUCLEATION phase transitions Steel metallurgy theRMODYNAMICS
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Line spectrum detection algorithm based on the phase feature of target radiated noise 被引量:4
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作者 Enming Zheng Huabing Yu +1 位作者 Xinhua Chen Changyu Sun 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2016年第1期72-80,共9页
In order to improve the performance of line spectrum detection,according to the feature that the underwater target radiated noise containing stable line spectrum,the differences of the phase difference between line sp... In order to improve the performance of line spectrum detection,according to the feature that the underwater target radiated noise containing stable line spectrum,the differences of the phase difference between line spectrum and background noise,a weighted line spectrum detection algorithm based on the phase variance is proposed in frequency domain.After phase difference alignment,the phase variance of line spectrum and the phase of background noise,respectively,are small and big in frequency domain,this method utilizes the weighted statistical algorithm to cumulate the frequency spectrum based on the phase variance,which can restrain the background noise disturbance,and enhance the signal to noise ratio(SNR).The theory analysis and experimental results both verify that the proposed method can well enhance the energy of line spectrum,restrain the energy of background noise,and have better detection performance under lower SNR. 展开更多
关键词 information processing underwater target detection line spectrum detection phase variance.
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Optimal design of left-lane line extensions considering non-yielding maneuvers at the beginning of the permitted phase 被引量:1
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作者 Qu Zhaowei  Bai Qiaowen +2 位作者 Chen Yongheng Cao Ningbo Xiong Shuai 《Journal of Southeast University(English Edition)》 EI CAS 2018年第1期120-126,共7页
In order to restrict non-yielding maneuvers of left-turning vehicles,an optimal design of left-lane line extensions is proposed to solve the problem.A field observation was conducted to collect a data set of left-turn... In order to restrict non-yielding maneuvers of left-turning vehicles,an optimal design of left-lane line extensions is proposed to solve the problem.A field observation was conducted to collect a data set of left-turning vehicles at the beginning of a green phase at two similar intersections(one with a permitted phase and the other with a protected phase).The comparative analysis shows no significant difference in the speed distribution using either a permitted phase or a protected phase,but it reveals that a permitted phase can lead to a larger acceleration when the left-turn vehicles pass through the conflict points.Those indicate the existence of non-yielding maneuvers of left-turn vehicles at signalized intersections with a permitted phase.Optimal designed left-lane line extensions contain two types of segments,circular curves and transition curves,and they are only related to four geometry parameters of an intersection.The proposed method is easy to use and it can offer reference for intersection channelization and traffic organization. 展开更多
关键词 left-turning vehicle permitted phase non-yielding maneuver optimal design left-lane line extensions
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The statistical laws of strong seismic motion phase characteristics
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作者 金星 廖振鹏 《Acta Seismologica Sinica(English Edition)》 CSCD 1994年第1期141-147,共7页
Under the assumption of an effective point source model,this paper introduces a conception of equivalent phase velocity to describle the average propagation processes and dispersion properties of seismic waves from se... Under the assumption of an effective point source model,this paper introduces a conception of equivalent phase velocity to describle the average propagation processes and dispersion properties of seismic waves from seismic source to the site,then illuminates the relation between the phase properties of seismic motion and equivalent phase velocity and obtains a simple formula of estimating the equivalent phase velocity through the use of the phase difference spectrum of seismic motion.After the parts of strong seismic records in the western American and the SMART-1 array are used to identify the method presented by this paper in reason,the statistical relations of equivalent phase velocity are given in the above two regions.The results of the paper have demonstrated that the phase spectrum of seismic motion has its inner law as same as the amplitude spectrum does. 展开更多
关键词 equivalent phase velocity relative phase velocity phase spectrum relative group velocity phase difference spectrum
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Study protocol of the Asian XELIRI ProjecT(AXEPT):a multinational,randomized,non-inferiority,phase Ⅲ trial of second-line chemotherapy for metastatic colorectal cancer, comparing the eicacy and safety of XELIRI with or without bevacizumab versus FOLFIRI w 被引量:3
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作者 Masahito Kotaka Ruihua Xu +22 位作者 Kei Muro Young Suk Park Satoshi Morita Satoru Iwasa Hiroyuki Uetake Tomohiro Nishina Hiroaki Nozawa Hiroshi Matsumoto Kentaro Yamazaki Sae-Won Han Wei Wang Joong Bae Ahn Yanhong Deng Sang-Hee Cho Yi Ba Keun-Wook Lee Tao Zhang Taroh Satoh Marc E.Buyse Baek-Yeol Ryoo Lin Shen Junichi Sakamoto Tae Won Kim 《Chinese Journal of Cancer》 SCIE CAS CSCD 2016年第12期735-742,共8页
Background: Capecitabine and irinotecan combination therapy(XELIRI) has been examined at various dose levels to treat metastatic colorectal cancer(m CRC). Recently, in the Association of Medical Oncology of the German... Background: Capecitabine and irinotecan combination therapy(XELIRI) has been examined at various dose levels to treat metastatic colorectal cancer(m CRC). Recently, in the Association of Medical Oncology of the German Cancer Society(AIO) 0604 trial, tri?weekly XELIRI plus bevacizumab, with reduced doses of irinotecan(200 mg/m^2 on day 1) and capecitabine(1600 mg/m^2 on days 1–14), repeated every 3 weeks, has shown favorable tolerability and eicacy which were comparable to those of capecitabine and oxaliplatin(XELOX) plus bevacizumab. The doses of capecit?abine and irinotecan in the AIO trial are considered optimal. In a phase I/II study, XELIRI plus bevacizumab(BIX) as second?line chemotherapy was well tolerated and had promising eicacy in Japanese patients.Methods: The Asian XELIRI Projec T(AXEPT) is an East Asian collaborative, open?labelled, randomized, phase Ⅲ clinical trial which was designed to demonstrate the non?inferiority of XELIRI with or without bevacizumab versus standard FOLFIRI(5?fluorouracil, leucovorin, and irinotecan combination) with or without bevacizumab as second?line chemo?therapy for patients with m CRC. Patients with 20 years of age or older, histologically conirmed m CRC, Eastern Coop?erative Oncology Group performance status 0–2, adequate organ function, and disease progression or intolerance of the irst?line regimen will be eligible. Patients will be randomized(1:1) to receive standard FOLFIRI with or with?out bevacizumab(5 mg/kg on day 1), repeated every 2 weeks(FOLIRI arm) or XELIRI with or without bevacizumab(7.5 mg/kg on day 1), repeated every 3 weeks(XELIRI arm). A total of 464 events were estimated as necessary to show non?inferiority with a power of 80% at a one?sided α of 0.025, requiring a target sample size of 600 patients. The 95% conidence interval(CI) upper limit of the hazard ratio was pre?speciied as less than 1.3.Conclusion: The Asian XELIRI Projec T is a multinational phase III trial being conducted to provide evidence for XELIRI with or without bevacizumab as a second?line treatment option of mCRC. 展开更多
关键词 Metastatic colorectal cancer Randomized phase clinical trial XELIRI BEVACIZUMAB Second-line therapy
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Microscopic Phase Field Study of the Spinodal Decomposition in Fe-Mo Alloys
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作者 朱景川 赵荣达 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2009年第S1期9-12,共4页
The spinodal decomposition in Fe-Mo alloys is studied by microscopic phase field method based on atomic scale.The results show that critical temperature of spinodal decomposition increases with the increment of Mo con... The spinodal decomposition in Fe-Mo alloys is studied by microscopic phase field method based on atomic scale.The results show that critical temperature of spinodal decomposition increases with the increment of Mo content,up to a maximum value of 1340 K at the Mo content of 50%.The spinodal decomposition shows a maximum rate at the Mo content of 50% for different Fe-Mo alloys.Comparing with the interconnected microstructure without considering elastic strain energy,the microstructure arrayed alternatively along the elastic soft direction of [01] and [10] is obtained under the effects of elastic strain energy,which will changes into a special 'macrolattice' structure during subsequent coarsening stages.The coarsening of microstructure is restrained by elastic interaction generated by atomic-size difference,and a larger atomic-size difference induces a stronger restraining effect. 展开更多
关键词 spinodal decomposition phase field Fe-Mo alloys atomic-size difference
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Feedback Control System for Antenna Phase Difference in the LHCD Experiments
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作者 蒋敏 匡光力 +3 位作者 单家芳 林建安 孔军 HT-7 Team 《Plasma Science and Technology》 SCIE EI CAS CSCD 2005年第6期3107-3110,共4页
It is well accepted that lower hybrid current drive (LHCD) is the most efficient method for non-inductive current drive in fusion devices and the effect of the current drive is dependent on not only microwave power ... It is well accepted that lower hybrid current drive (LHCD) is the most efficient method for non-inductive current drive in fusion devices and the effect of the current drive is dependent on not only microwave power but also its grill phase shift. This paper presents a new kind of feedback control system for antenna phase difference in LHCD experiments. In this highspeed control system, a lot of new technologies and methods are incorporated. The results of the experiments show a very good agreement with the system design. 展开更多
关键词 lower hybrid current drive (LHCD) feedback control system antenna phase difference
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The microstructural nanoindentation characteristics of different phases in precision annealed GCr15 steel
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作者 Zhang Junbao Yang Xiaoping Wang Xiufang Shi Bi Song Hongwei 《Baosteel Technical Research》 CAS 2008年第4期51-54,共4页
This study characterizes the mechanical properties and volume fractions of the different phases in precision annealed GCr15 steel using nanoindentation technology. Experimental results indicate that the nanoindentatio... This study characterizes the mechanical properties and volume fractions of the different phases in precision annealed GCr15 steel using nanoindentation technology. Experimental results indicate that the nanoindentation hardness of cementite grains is between 14.15 GPa and 17.61 GPa,with a mean value of 15.40 GPa. This hardness is much higher than the hardness of ferrite grains. The nanoindentation hardness of ferrite is between 2.78 GPa and 4.89 GPa, with a mean value of 3.35 GPa. The volume fractions of the different phases were also determined using nanoindentation technology, and the volume fraction of cementite in the steel was identified as 15%. 展开更多
关键词 NANOINDENTATION GCr15 steel mechanical properties of microstructures volume fractions of different phases
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Influence on the Lifetime of ^(87)Rb Bose-Einstein Condensation for Far-Detuning Single-Frequency Lasers with Different Phase Noises
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作者 Peng Peng Liang-hui Huang +3 位作者 Dong-hao Li Peng-jun Wang Zeng-ming Meng Jing Zhang 《Chinese Physics Letters》 SCIE CAS CSCD 2018年第6期24-27,共4页
We study the influence of the phase noises of far detuning single frequency lasers on the lifetime of Bose-Einstein condensation(BEC)of^(87)Rb in an optical dipole trap.As a comparison,we shine a continuous-wave s... We study the influence of the phase noises of far detuning single frequency lasers on the lifetime of Bose-Einstein condensation(BEC)of^(87)Rb in an optical dipole trap.As a comparison,we shine a continuous-wave singlefrequency Ti:sapphire laser,an external-cavity diode laser and a phase-locked diode laser on BEC.We measure the heating and lifetime of BEC in two different hyperfine states:|F=2,m_F=2〉and|F=1,m_F=1〉.Due to the narrow linewidth and small phase noise,the continuous-wave single-frequency Ti:sapphire laser has less influence on the lifetime of^(87)Rb BEC than the external-cavity diode laser.To reduce the phase noise of the external-cavity diode laser,we use an optical phase-locked loop for the external-cavity diode laser to be locked on a Ti:sapphire laser.The lifetime of BEC is increased when applfying the phase-Jocked diode laser in contrast with the external-cavity diode laser. 展开更多
关键词 Influence on the Lifetime of Rb Bose-Einstein Condensation for Far-Detuning Single-Frequency Lasers with Different phase Noises BEC
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Determination Method of Focal Depth of Local Earthquake Using the Travel-time Difference between Pn and sPn
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作者 Wang Dengwei Xu Qinping Ma Fuhong Cheng Xuefen 《Earthquake Research in China》 2011年第3期300-309,共10页
In this paper,we derived the relationships between the travel time difference of sPn and Pn and the local earthquake focal depth.In these equations,the travel time difference of sPn and Pn is not related to the epicen... In this paper,we derived the relationships between the travel time difference of sPn and Pn and the local earthquake focal depth.In these equations,the travel time difference of sPn and Pn is not related to the epicentral distance,but depends only on the regional crustal mode and the focal depth.According to the equations,we provided a simple and accurate method to determine local earthquake focal depth by using the travel time difference between phase sPn and Pn.This method has been used to determine the focal depths of two earthquake of MS6.1 and MS5.6 which occurred at the junction of Panzhihua and Huili,Sichuan on August 30 and 31,2008.The results were compared to those from other sources such as the China Earthquake Networks Center,and the comparison shows that the results are accurate and reliable. 展开更多
关键词 Focal depth sPn seismic phase Travel-time difference between sPn and Pn Critical epicentral distance
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Observability of Airborne Passive Location System with Phase Difference Measurements 被引量:4
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作者 邓新蒲 王强 钟丹星 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2008年第2期149-154,共6页
With a pair of antennas spaced apart, an airborne passive location system measures phase differences of emitting signals. Regarded as cyclic ambiguities, the moduli of the measurements traditionally are resolved by ad... With a pair of antennas spaced apart, an airborne passive location system measures phase differences of emitting signals. Regarded as cyclic ambiguities, the moduli of the measurements traditionally are resolved by adding more antenna elements. This paper models the cyclic ambiguity as a component of the system state, of which the observability is analyzed and compared to that of the bear- ings-only passive location system. It is shown that the necessary and sufficient observability condition for the bearings-only passive location system is only the necessary observability condition for the passive location system with phase difference measurements, and that when the system state is observable, the cyclic ambiguities can be estimated by accumulating the phase difference measurements, thereby making the observer able to locate the emitter with high-precision. 展开更多
关键词 passive location phase difference OBSERVABILITY ACCURACY
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SOLID-STATE VARIABLE-TEMPERATURE NMR STUDY ON THE PHASE SEPARATION OF POLYETHER POLYURETHANE ZWITTERIONOMERS
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作者 杨光 陈群 +2 位作者 王源身 杨昌正 邬学文 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1994年第4期302-308,共7页
Polyether-polyurethane zwitterionomers based on 4, 4'-diphenylmethane diisocyanate(MDI), methyl diethanolamine (MDEA), and polytetramethylene oxide glycol (PTMO) werestudied with variable-temperature wide-line ~1H... Polyether-polyurethane zwitterionomers based on 4, 4'-diphenylmethane diisocyanate(MDI), methyl diethanolamine (MDEA), and polytetramethylene oxide glycol (PTMO) werestudied with variable-temperature wide-line ~1H NMR. It is found that upon ionization, degree ofphase separation in the polymer system decreased at first due to the loss of hard segmentregularity, while further ionization increased the degree of phase separation through increasinghard phase cohesion and difference of polarity between hard and soft segments. 展开更多
关键词 Polyether polyurethane Variable temperature Wide-line NMR phase separation
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