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1.
提出了一种新的衡量散射体系中散射颗粒消光能力、散射能力和吸收能力的方法并与传统方法进行了比较。在此基础上 ,讨论了散射颗粒折射率和颗粒大小对其散射能力的影响。运用此方法可以为各种散射体系 ,尤其是强散射体系选择恰当的散射颗粒 ,其结果优于用传统方法所得的结果  相似文献   

2.
Proton-proton fusion is considered in the effective field theory of Kaplan, Savage and Wise. Coulomb effects are included systematically in a non-perturbative way. Including the dimension-eight derivative coupling which determines the effective ranges of the scattering amplitudes, next-to-leading order corrections to the fusion rate are calculated. When the renormalization mass is well above the characteristic energies of the system, this contribution gives a rate which is eight percent below the standard value. The difference can be due to an unknown counterterm which comes in at this order.  相似文献   

3.
With reference to the equivalence theorem, we discuss the selection of basis operators for effective field theories in general. The equivalence relation can be used to partition operators into equivalence classes, from which inequivalent basis operators are selected. These classes can also be identified as containing Potential-Tree-Generated (PTG) operators, Loop-Generated (LG) operators, or both, independently of the specific dynamics of the underlying extended models, so long as it is perturbatively decoupling. For an equivalence class containing both, we argue that the basis operator should be chosen from among the PTG operators, because they may have the largest coefficients. We apply this classification scheme to dimension-six operators in an illustrative Yukawa model as well in the Standard Model (SM). We show that the basis chosen by Grzadkowski et al. [5] for the SM satisfies this criterion. In this light, we also revisit and verify our earlier result [6] that the dimension-six corrections to the triple-gauge-boson couplings only arise from LG operators, so the magnitude of the coefficients should only be a few parts per thousand of the SM gauge coupling if BSM dynamics respects decoupling. The same is true of the quartic-gauge-boson couplings.  相似文献   

4.
The extended Krenciglowa-Kuo (EKK) method allows us to calculate the effective Hamiltonian in a non-degenerate model space. We show that the EKK method can be implemented numerically in two iterative schemes, which are explained in detail with emphasis on convergence conditions. Using test calculations in a simple model, we clarify how and on what conditions we can calculate the effective Hamiltonian.  相似文献   

5.
从原子间相互作用及运动出发,阐明SiC在高温高压下溶于金属触媒中形成金刚石的原子过程,并在此基础上进而阐明Ni70Mn25Co5是促使SiC形成金刚石的高效率触媒合金。日本文部省的资助  相似文献   

6.
Based on numerical simulation, we theoretically study the linear and nonlinear properties of microstructured fiber. Using the fully vectorial effective index method, we calculate the effective refractive index for different air hole size. We show how the linear properties such as spot size, numerical aperture, splice loss and bend loss can be controled by changing the air hole size. We also propose the same method for analysing effective area and self-phase modulation of microstructured fiber for different designing parameters. We compare all our results with other numerical methods.  相似文献   

7.
Geometric –models have been defined as purely geometric theories of scalar fields in interaction with gravity. By construction, these theories possess soliton solutions with topologically nontrivial scalar sectors. We perform a detailed analysis of the stability of the effective scalar field theory far from the soliton core. It is shown that the requirement for the asymptotic stability is consistent with the existence of massive, static, spherically symmetric soliton solutions.  相似文献   

8.
原子吸收光谱法测定土壤中有效铜和锌的不确定度评估   总被引:1,自引:0,他引:1  
邢雁  李勇泽  赵玮 《光谱实验室》2012,29(2):1164-1167
对火焰原子吸收光谱法测定土壤中的有效铜和锌含量不确定度进行评定,分析了整个检测过程产生不确定度的原因,给出扩展不确定度以及最终结果表示:有效铜5.8±0.056mg/kg,有效锌1.14±0.022mg/kg,并且分析产生不确定度的主要来源,为控制该方法测定土壤中有效铜和锌提供可靠的理论依据。  相似文献   

9.
10.
越荣中  冯苗  詹红兵 《光子学报》2014,40(12):1860-1864
理论分析了单层银纳米颗粒及其复合超材料的电磁特性,并采用MATLAB数值计算和CST模拟对理论进行了验证.结果显示:4.75 nm银颗粒所形成的单层阵列的数值和模拟结果都有Lorentz共振效应出现,模拟结果相对于数值计算有红移现象,且有微弱的磁共振效应.进一步对采用4.75 nm颗粒复合而成的100 nm大颗粒模拟,结果表明:在800~1 000 nm区间共振得到负的实有效介电常量、负的实有效磁导率和负的折射率,说明100 nm复合球形颗粒具有很强的磁共振效应,与理论分析相符.  相似文献   

11.
文中以有效介质近似理论为基础,考虑了纳米颗粒在基液中强烈的B rown ian运动对强化传热的作用和纳米颗粒的表面吸附液体层、纳米颗粒的粒径和体积分数对纳米悬浮液有效导热系数的影响,建立了预测纳米悬浮液有效导热系数的模型,通过对纳米CuO-去离子水溶液的验证,发现该模型比几种经典模型具有更高的精度,因此具有一定的参考价值。  相似文献   

12.
We introduce the concept of effective electron drift mobility for multiwalled carbon nanotubes. This effective quantity is calculated under a quantum-box approach to conceive quantum transport in a given multiwalled carbon nanotube. In addition, effective motion time is determined.  相似文献   

13.
D P Ahalpara  K H Bhatt 《Pramana》1978,11(1):35-37
The separation betweenT=0 andT=1 centroids of the empirical effective interaction is fairly large for the (d 3 2/−1 f 7/2)JT particle-hole interaction as compared to nearby (f 7/2)2 JT and (d 5/2)2 JT particle-particle interactions. This interesting feature of the empirical effective interaction is shown to arise as a consequence of renormalization of the effective interaction as one truncates the configuration space from (sd)−1(fp)1 to (d 3 2/−1 f 7/2) and from (fp)2 and (sd)2 configurations to (f 7/2)2 and (d 5/2)2 respectively.  相似文献   

14.
非对称条件下三体索末菲参量的修正   总被引:2,自引:2,他引:0  
在非对称几何条件下导出新的有效索末菲参量,对BBK理论提出了修正,并运用修正后的BBK理论计算了中能电子离化He原子的三重微分截面(TDCS),所得结果与BBK理论计算进行比较发现:这种修正明显地改善了binary峰与实验数据的符合程度。  相似文献   

15.
We study the effective conductivity e for a random wire problem on the d-dimensional cubic lattice d , d2 in the case when random conductivities on bonds are independent identically distributed random variables. We give exact expressions for the expansion of the effective conductivity in terms of the moments of the disorder parameter up to the 5th order. In the 2D case using the duality symmetry we also derive the 6th order expansion. We compare our results with the Bruggeman approximation and show that in the 2D case it coincides with the exact solution up to the terms of 4th order but deviates from it for the higher order terms.  相似文献   

16.
We present a thermodynamic approach to introducing quantum corrections to the classical transport picture in semiconductor device simulation. The approach leads to a modified Boltzmann equation with an effective quantum potential that takes into account the Hartree and the barrier contributions. We study the influence of the quantum effects on the device output current.  相似文献   

17.
The one-loop effective action of QED is calculated by the Schwinger method in Krein space quantization. We show that the effective action is naturally finite and regularized. It also coincides with the renormalized solution which was derived by Schwinger.  相似文献   

18.

In this study the model suggested by Sugiyama has been developed and applied for the calculation of the stopping powers for nonrelativistic heavy ions in various target materials. Sugiyama's model has been expanded to low and high energy regions in our work. Analytical expressions are obtained in the modified BB stopping power formula for the effective charge and effective mean excitation energies. In the modified LSS formula, a quasi-molecule criterion has been applied to both the projectiles and the target atoms. Electronic excitation contribution, S e0, and quasi-molecule contribution, S ei , to stopping power were found for a wide energy region. It is observed that in intermediate energy region both contributions have maxima. The stopping power due to excitation-ionization in the intermediate and higher energy region is found to be dominant, whereas quasi-molecule contribution is dominant in the lower energy region. The calculated results of stopping power are in good agreement with experimental data for various ions and targets within a few percent in a wide projectile energy range.  相似文献   

19.
Identifying the fundamental degrees of freedom of a black hole poses a long-standing puzzle. Recently Goldberger and Rothstein forwarded a theory of the low frequency degrees of freedom within the effective field theory approach, where they are relevancy ordered but of unclear physical origin. Here these degrees of freedom are identified with near-horizon but non-compact gravitational perturbations which are decomposed into delocalized multipoles. Their world-line (kinetic) action is determined within the classical effective field theory (CLEFT) approach and their interactions are discussed. The case of the long-wavelength scattering of a scalar wave off a Schwarzschild black hole is treated in some detail, interpreting within the CLEFT approach the equality of the leading absorption cross section with the horizon area. Fifth Award in the 2008 Essay Competition of the Gravity Research Foundation.  相似文献   

20.
A.B. Balakin 《Annals of Physics》2008,323(9):2183-2207
We formulate a self-consistent non-minimal five-parameter Einstein-Yang-Mills-Higgs (EYMH) model and analyse it in terms of effective (associated, color and color-acoustic) metrics. We use a formalism of constitutive tensors in order to reformulate master equations for the gauge, scalar and gravitational fields and reconstruct in the algebraic manner the so-called associated metrics for the Yang-Mills field. Using WKB-approximation we find color metrics for the Yang-Mills field and color-acoustic metric for the Higgs field in the framework of five-parameter EYMH model. Based on explicit representation of these effective metrics for the EYMH system with uniaxial symmetry, we consider cosmological applications for Bianchi-I, FLRW and de Sitter models. We focus on the analysis of the obtained expressions for velocities of propagation of longitudinal and transversal color and color-acoustic waves in a (quasi)vacuum interacting with curvature; we show that curvature coupling results in time variations of these velocities. We show, that the effective metrics can be regular or can possess singularities depending on the choice of the parameters of non-minimal coupling in the cosmological models under discussion. We consider a physical interpretation of such singularities in terms of phase velocities of color and color-acoustic waves, using the terms “wave stopping” and “trapped surface”.  相似文献   

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