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341.
342.
By a laser vaporization/pulsed molecular beam method,the carbon anion clusters (n=1 to 45) are produced and analyzed. An evident odd-even abundance alternation pattern is observed,with the even-numbered (n=8,10,14,16,18,20,22,24,26,28 and 30) standing out. It can also be observed that the peaks at n=5 and n=13 are prominent. Compared with the results obtained by other authors,a discussion concerning cluster structures is made. 相似文献
343.
An effective Hamiltonian of the two-dimensional antiferromagnetic Heisenberg model is derived by using the Holstein-Primakoff transformation. Three nonlinear coupled partial equations of motion are obtained. In the long-wavelength approximation, these equations, are reduced to the envelope function equations by the method of multiple scales. The amplitude functions satisfy the nonlinear Schrodinger equation. Introducing an inverse scatteriag transformation, the single-, two- and multi-soliton solutions in the two-dimensional antiferromagnetic Heisenberg model are investigated. 相似文献
344.
LIU Yu-Fen 《理论物理通讯》2006,46(3):481-492
It is proved that there exists a vector representation of Dirac's spinor field and. in one sense it is equivalent to biquaternion (i.e. complexified quaternion) representation. This can be considered as a generalization of Cartan's idea of triality to Dirac's spinors. In the vector representation the first-order Dirac Lagrangian is dual-equivalent to the two-order Lagrangian of topologically massive gauge field. The potential field which corresponds to the Dirac field is obta/ned by using master (or parent) action approach. The novel gauge field is self-dual and contains both anti-symmetric Lee and symmetric Jordan structure. 相似文献
345.
The two-dimensional (2D) nonlinear Rossby waves described by the Petviashvili equation, which has been invoked as an ageostrophic extension of the barotropic quasi-geostrophic
potential vorticity equation, can be investigated through the exact periodic-wave solutions for the Petviashvili equation, while the exact analytical periodic-wave solutions to the
Petviashvili equation are obtained by using the Jacobi elliptic function expansion method. It is shown that periodic-wave 2D Rossby solutions can be obtained by this method, and in the limit cases, the 2D Rossby soliton solutions are also obtained. 相似文献
346.
ICP-AES法测定钕铁硼永磁材料中常量元素 总被引:1,自引:0,他引:1
刘永明 《光谱学与光谱分析》2004,24(10):1257-1259
研究了等离子发射光谱法 (ICP AES)直接测定钕铁硼永磁材料中常量元素Nd ,Fe,B的方法。选择了合适的分析线 ,采用基体匹配法消除样品中基体元素的干扰。详细讨论了ICP AES法测定硼的“记忆效应”及其消除方法。以多点 (3个点 )标准曲线法减小测定的误差。本方法已应用于钕铁硼产品的快速检验 ,样品中Nd ,Fe,B含量测定的相对标准偏差分别为 0 6 2 % ,0 5 6 % ,0 90 % 相似文献
347.
在 p H4 .8的邻苯二甲酸氢钾 - Na OH介质中 ,非离子表面活性剂 Tween- 80存在下 ,7- (苯并噻唑 - 2 -偶氮 ) - 8-羟基喹啉 - 5 -磺酸 (BTAQS)与镉形成 2∶ 1的紫红色配合物 ,其最大吸收波长 λmax=5 6 0 nm,表观摩尔吸光系数为 8.71× 10 4L· mol-1·cm-1,镉含量在 0— 6 μg/ 10 m L范围内服从比耳定律。用于矿样中镉的测定 ,相对误差小于 3% ,相对标准偏差小于 2 .5 % (n=5 )。 相似文献
348.
349.
We improve the isospin dependent quantum molecular dynamical model by including isospin effects in the Skyrme potential and the momentum dependent interaction to obtain an isospin dependent Skyrme potential and an isospin dependent momentum interaction. We investigate the isospin effects of Skyrme potential and momentum dependent interaction on the isospin fractionation ratio and the dynamical mechanism in intermediate energy heavy ion collisions. It is found that the isospin dependent Skyrme potential and the isospin dependent momentum interaction produce some important isospin effects in the isospin fractionation ratio. 相似文献
350.
At least two bunchers are needed in the 3 MeV H- Medium Energy Beam Transport(MEBT)line located between RFQ and DTL for the CSNS(China Spallation Neutron Source).A nose-cone geometry has been adopted as the type of buncher cavity for its simplicity,higher impedance and lower risk of multipacting.By making use of the results got from the simulations on the buncher with two-dimension code SUPERFISH,the thermal and structural analyses have been carried out,the process and results to determine the resulting frequency shift due to thermal and structural distortion of the cavity are presented,the water-cooling channel position and the optimum cooling water temperature as well as the tuning method by adjusting the cooling water temperature when the cavity is out of resonance are also determined through the analyses. 相似文献