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THE INVARIANT REPRESENTATION OF SPINS WITH APPLICATIONS IN THE THEORY OF FINITE DEFORMATIONS

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Acta Mechanica Sinica 1990年第2期6卷 133-140页

作者： Wang Wenbiao (div.of physics,Graduate School Univ.of Science and Technology of China,Beijing 100039)Duan Zhuping (Lab.for Non-linear Mechanics of Continuous Media,Institute of Mechanics,Academia Sinica,Beijing 100080) div. of physics Graduate School Univ. of Science and Technology of China Beijing Lab. for Non-linear Mechanics of Continuous Media Institute of Mechanics Beijing

Based on the general solution given to a kind of linear tensor equations,the spin of a symmetric tensor is derived in an invariant *** result is applied to find the spins of the left and the tight stretch tensors and the relation among different rotation rate tensors has been *** to work conjugacy,the relations between Cauchy stress and the stresses conjugate to Hill's generalized strains are ***,the logarithmic strain,its time rate and the conjugate stress have been discussed in de- *** results are important in modeling the constitutive relations for finite deformations in continuum me- chanics.

关键词： spin generalized strain rate conjugate stress finite deformation

PERFORMANCE ANALYSIS AND SIMULATION OF OCDMA SYSTEM BASED ON FBGs ENCODER/DECODER

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Journal of Electronics(China) 2005年第6期22卷 663-670页

作者： Li Chuanqi Sun Xiaohan Je-Myung Jeong Dept of physics Nanjing University of Information Science ＆ Technology Nannjing 210044 China Dept of Electronics Engineering Southeast University Nanjing 210096 China Optical Commun. Lab Div. of Electric and Computer Eng. Hanyang Univ. Seoul 133-791 Korea

The encoding/decoding scheme based on Fiber Bragg Grating (FBG) for Optical Code div.sion Multiple Access (OCDMA) system is analyzed and the whole process from transmitting end to receiving end is researched in detail. The mathematical mode including signal transmission, summing, receiving and recovering are established respectively. One of the main sources of Bit Error Rate (BER) of OCDMA system based on FBGs is the unevenness of signal power spectrum, which leads to the chip powers unequal with each other. The Signal to Interfere Ratio (SIR) and BER performance of the system are studied and simulated at the case with uneven distribution of chips' powers.

关键词： Optical Code div.sion Multiple Access (OCDMA) Fiber Bragg Grating (FBG) Optical encoder/decoder

GRADIENT ESTIMATES FOR THE COMMUTATOR WITH FRACTIONAL DIFFERENTIATION FOR SECOND ORDER ELLIPTIC OPERATORS

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Acta Mathematica Scientia 2019年第5期39卷 1255-1264页

作者： Wenyu TAO bnping CHEN Jili LI Department of Applied Mathematics School of Mathematics and PhysicsUniversity of Science and Technology Beijing

Let L=-div.A▽) be a second order div.rgence form elliptic operator, where A is an accretive, n×n matrix with bounded measurable complex coefficients on R^n. Let L^α/2 (0 <α< 1) denotes the fractional differential operator associated with L and (-△)^α/2b ∈ L^n/α(R^n). In this article, we prove that the commutator[b, L^α/2] is bounded from the homogenous Sobolev space Lα%2 (R^n) to L^2(R^n).

关键词： commutator fractional differentiation elliptic operators Sobolev space

L^p-gradient estimates for the commutators of the Kato square roots of second-order elliptic operators on R^n

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Science China Mathematics 2020年第3期63卷 575-594页

作者： Wenyu Tao Yanping Chen Yayuan Xiao Liwei Wang School of Mathematics and physics University of Science and Technology BeijingBeijing 100083China Department of Mathematical Sciences Ball State UniversityMuncieIN 47306USA School of Mathematics and physics Anhui Polytechnic UniversityWuhu 241000China

Let L=-div.A▽） be a second-order div.rgent-form elliptic operator,where A is an accretive n×n matrix with bounded and measurable complex coefficients on Herein,we prove that the commutator [b,L1/2]of the Kato square root L1/2 and b with ▽b∈Ln（Rn）（n> 2）,is bounded from the homogenous Sobolev space L1p（Rn） to Lp（Rn）（p-（L）

关键词： commutator Kato square root elliptic operators Sobolev space

BV SOLUTIONS TO A DEGENERATE PARABOLIC EQUATION FOR IMAGE DENOISING

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Acta Mathematica Scientia 2007年第1期27卷 169-179页

作者：孔令海郇中丹郭柏灵 Institute of Applied physics and Computational Mathematics P.O.Box 8009-13 School of Mathematical Sciences Beijing Normal University Center for Nonlinear Studies Institute of Applied physics and Computational Mathematics P.O.Box 8009Beijing 100088China

In this article, the authors consider equation ut = div.φ（Γu）A（｜Du｜^2）Du） - （u- I）, where φ is strictly positive and F is a known vector-valued mapping, A ： R＋ → R^＋ is decreasing and A（s） -1/ √s as s →　＋∞. This kind of equation arises naturally from image denoising. For an initial datum I ∈ BVloc ∩ L^∞, the existence of BV solutions to the initial value problem of the equation is obtained.

关键词： BVloc function BV∞ function strongly degenerate parabolic denoising

Ingredients-based Methodology and Fuzzy Logic Combined Short-Duration Heavy Rainfall Short-Range Forecasting:An Improved Scheme

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Journal of Tropical Meteorology 2024年第3期30卷 241-256页

作者： TIAN Fu-you XIA Kun SUN Jian-hua ZHENG Yong-guang HUA Shan National Meteorological Center Beijing100081 China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric PhysicsChinese Academy of Sciences(IAP/CAS)Beijing 100029 China Key Laboratory of Cloud-Precipitation physics and Severe Storms(LACS) Institute of Atmospheric PhysicsChinese Academy of Sciences(IAP/CAS)Beijing 100029 China

Short-duration heavy rainfall(SHR),as delineated by the National Meteorological Center of the China Me-teorological Administration,is characterized by hourly rainfall amounts no less than 20.0 *** is one of the most common convective weather phenomena that can cause severe ***-range forecasting of SHR is an important part of operational severe weather *** the present study,an improved objective SHR forecasting scheme was developed by adopting the ingredients-based methodology and using the fuzzy logic *** 1.0°×1.0°National Centers for Environmental Prediction(NCEP)final analysis data and the ordinary rainfall(0.1-19.9 mm h-1)and SHR observational data from 411 stations were used in the improved *** best lifted index,the total precipitable water,the 925 hPa specific humidity(Q 925),and the 925 hPa div.rgence(div.925)were selected as predictors based on objective *** distributed membership functions of predictors were obtained based on relative frequency *** weights of predictors were also objectively *** with a typhoon SHR case and a spring SHR case show that the main possible areas could be captured by the improved *** of SHR forecasts within 96 hours with NCEP global forecasts 1.0°×1.0°data initiated at 08:00 Beijing Time during the warm seasons in 2015 show the results were improved from both deterministic and probabilistic *** study provides an objectively feasible choice for short-range guidance forecasts of *** scheme can be applied to other convective phenomena.

关键词： ingredients-based methodology fuzzy logic approach probability of short-duration heavy rainfall(SHR) improved forecasting scheme objectively obtained membership functions

Interatomic Potentials for Some Binary Oxides

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Journal of Materials Science & Technology 2001年第6期17卷 638-642页

作者： M.Nadeem, M.J.Akhtar, R.Shaheen and M.N.Haque Nuclear physics div.sion, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad, Pakistan A.Y.Khan Department of Chemistry, Quaid-i-Azam University, Islamabad, Pakistan Inst Nucl Sci & Technol Div Nucl Phys Islamabad Pakistan

Using atomistic computer simulation methods we have derived a new set of interatomic potential parameters for some binary oxides, comprising div.lent transition elements (rock-salt structured) and tetravalent metals. Computational techniques based on the minimization of the crystal energy with respect to atomic coordinates have been employed. Crystal properties were calculated and compared with the experimental data to check the reliability of our potential models. Intrinsic (Schottky and Frenkel) defect energies were also calculated and compared with previous studies. There is a good agreement between these calculations, which shows that the new potential parameters are reliable and can be used with confidence for future investigations.

关键词： constants Frenkel derivation coordinates struc div.lent Faraday ionic fitting dipole

Bc（B）→div.- Form Factors in Light-Cone Sum Rules and the D-Meson Distribution Amplitude

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Chinese physics Letters 2007年第1期24卷 61-64页

作者：左芬黄涛 Institute of High Energy physics Chinese Academy of Sciences Beijing 100049

We calculate the weak form factors of the decays Be（B） → Dlv^- by using the chiral current correlator within the framework of the QCD light-cone sum rules （LCSRs）. The expressions of the form factors only depend on the leading twist distribution amplitude （DA） of the D meson. Three models of the D-meson distribution amplitude are employed. Our prediction, by using the D-meson distribution amplitude with the exponential suppression at the end points, favours the three-points sum rule （3PSR） approach with the Coulomb corrections included, and is compatible with other approaches.

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Numerical analysis of modal tomography for solar multi-conjugate adaptive optics

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Research in Astronomy and Astrophysics 2012年第4期12卷 465-471页

作者： Bing Dong De-Qing Ren Xi Zhang physics ＆ Astronomy Department California State University Northridge CA 91330-8268 USA National Astronomical Observatories/Nanjing Institute of Astronomical Optics ＆ Technology Chinese Academy of Sciences Nanjing 210042 China

Multi-conjugate adaptive optics （MCAO） can considerably extend the cor- rected field of view with respect to classical adaptive optics, which will benefit solar observation in many aspects. In solar MCAO, the Sun structure is utilized to provide multiple guide stars and a modal tomography approach is adopted to implement three- dimensional wavefront restorations. The principle of modal tomography is briefly re- viewed and a numerical simulation model is built with three equivalent turbulent lay- ers and a different number of guide stars. Our simulation results show that at least six guide stars are required for an accurate wavefront reconstruction in the case of three layers, and only three guide stars are needed in the two layer case. Finally, eigen- mode analysis results are given to reveal the singular modes that cannot be precisely retrieved in the tomography process.

关键词： instrumentation: multi-conjugate adaptive optics -- tomography