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891.
在Brueckner-Hartree-Fock理论框架内, 研究了同位旋非对称核物质中质子和中子单粒子势的动量相关性及其随同位旋非对称度的变化, 在此基础上计算了同位旋对称势, 并讨论了三体核力的影响. 结果表明同位旋对称势对于同位旋非对称度的依赖性很弱, 但对于动量和密度均有较强的依赖性. 当密度固定时, 同位旋对称势随动量增加而减小. 尽管三体核力对于质子和中子单粒子势的动量相关性有较大影响, 但对同位旋对称势的影响很小. 还与目前重离子碰撞输运理论模型中所使用的各种参数化的唯象对称势进行了比较. 相似文献
892.
893.
894.
研究Chetaev型约束力学系统Appell方程的Lie对称性和Lie对称性直接导致的守恒量.分析Lagrange函数和A函数的关系;讨论Chetaev型约束力学系统Appell方程的Lie对称性导致的守恒量的一般研究方法;在群的无限小变换下,给出Appell方程Lie对称性的定义和判据;得到Lie对称性的结构方程以及Lie对称性直接导致的守恒量的表达式.举例说明结果的应用.
关键词:
Appell方程
Chetaev 型约束力学系统
Lie对称性
守恒量 相似文献
895.
The stability and bifurcation analyses of periodic motions in a rotating blade subject to a torsional excitation are investigated. For high speed rotations, cubic geometric nonlinearity and gyroscopic effects of the rotating blade are considered. From the Galerkin method, the partial differential equation of the nonlinear rotating blade is simplified to the ordinary differential equations, and periodic motions and stability of the rotating blade are studied by the generalized harmonic balance method. The analytical and numerical results of periodic solutions are compared. The rich dynamics and co-existing periodic solutions of the nonlinear rotating blades are investigated. 相似文献
896.
Phase diagram, crystal chemistry and thermoelectric properties of compounds in the Ca-Co-Zn-O system
W. Wong-Ng T. Luo W.H. Tang Q. Huang S. Chattopadhyay T. Tritt 《Journal of solid state chemistry》2011,184(8):2159-2166
In the Ca-Co-Zn-O system, we have determined the tie-line relationships and the thermoelectric properties, solid solution limits, and structures of two low-dimensional cobaltite series, Ca3(Co, Zn)4O9−z and Ca3(Co,Zn)2O6−z at 885 °C in air. In Ca3(Co,Zn)4O9−z, which has a misfit layered structure, Zn was found to substitute in the Co site to a limit of Ca3(Co3.8Zn0.2)O9−z. The compound Ca3(Co,Zn)2O6−z (n=1 member of the homologous series, Can+2(Co,Zn)n(Co,Zn)′O3n+3−z) consists of one-dimensional parallel (Co,Zn)2O66− chains that are built from successive alternating face-sharing (Co,Zn)O6 trigonal prisms and ‘n’ units of (Co,Zn)O6 octahedra along the hexagonal c-axis. Zn substitutes in the Co site of Ca3Co2O6 to a small amount of approximately Ca3(Co1.95Zn0.05)O6−z. In the ZnO-CoOz system, Zn substitutes in the tetrahedral Co site of Co3O4 to the maximum amount of (Co2.49Zn0.51)O4−z and Co substitutes in the Zn site of ZnO to (Zn0.94Co0.06)O. The crystal structures of (Co2.7Zn0.3)O4−z, (Zn0.94Co0.06)O, and Ca3(Co1.95 Zn0.05)O6−z are described. Despite the Ca3(Co, Zn)2O6−z series having reasonably high Seebeck coefficients and relatively low thermal conductivity, the electrical resistivity values of its members are too high to achieve high figure of merit, ZT. 相似文献
897.
Magnetic solid‐phase extraction of angiotensin II receptor antagonists in human urine and plasma with a reversed‐phase/cation‐exchange mixed‐mode sorbent
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Biocompatible magnetic nanoparticles that featured divinylbenzene and sulfonate functionalities were used for the magnetic solid‐phase extraction of five angiotensin II receptor antagonists from human urine and plasma samples based on a reversed‐phase and cation‐exchange mixed‐mode mechanism. Under the optimized extraction conditions, coupled to high‐performance liquid chromatography with fluorescence detection, this proposed method was found to be accurate and precise with relative standard deviations of less than 11.7%, and a good recovery of 80.1–119.5% for both samples. The linear ranges were 0.2–2000 and 0.2–2500 ng/mL along with correlation coefficients above 0.9923 and 0.9928 for urine and plasma samples, respectively. Limits of detection were 0.01–5.74 and 0.01–1.31 ng/mL, respectively. The proposed magnetic solid‐phase extraction based on the magnetic nanoparticles functionalized with divinylbenzene and sulfonate was a reliable and convenient sample pretreatment method and had the potential for isolating and enriching the angiotensin II receptor antagonists in biological samples. 相似文献
898.
899.
This paper aims at showing that the class of augmented Lagrangian functions for nonlinear semidefinite programming problems can be derived, as a particular case, from a nonlinear separation scheme in the image space associated with the given problem. By means of the image space analysis, a global saddle point condition for the augmented Lagrangian function is investigated. It is shown that the existence of a saddle point is equivalent to a regular nonlinear separation of two suitable subsets of the image space. Without requiring the strict complementarity, it is proved that, under second order sufficiency conditions, the augmented Lagrangian function admits a local saddle point. The existence of global saddle points is then obtained under additional assumptions that do not require the compactness of the feasible set. Motivated by the result on global saddle points, we propose two modified primal-dual methods based on the augmented Lagrangian using different strategies and prove their convergence to a global solution and the optimal value of the original problem without requiring the boundedness condition of the multiplier sequence. 相似文献
900.