Dynamical spin susceptibility of the d–p model in the over doping region

Dynamical spin susceptibility χ^s(q,ω) of the d–p model in the over doping region is investigated by using the auxiliary boson technique. It includes higher order terms of the 1/N-expansion within the random phase approximation (RPA) of the local vertex, where frequency dependence of the quasi-particle interaction is taken into account. The incommensurate spin fluctuation is obtained due to the nesting effect in the low energy region (ωω^*), whereas the commensurate one in the high energy region (ωω^*), the characteristic energy ω^* is estimated to be about 30 meV. Both of the spin–lattice relaxation rate 1/T₁ and the spin–spin relaxation rate 1/T_g monotonically increase as T decreases, while the spin Knight shift K is almost independent of T.     

Study of the Thermal Diffusivity of Optical Coating by Photo－thermal Deformation Technique

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A molecular dynamics study of the stress–optical behavior of a linear short-chain polyethylene melt under shear

In this study, we present details of the stress–optical behavior of a linear polyethylene melt under shear using a realistic potential model. We demonstrate the existence of the critical shear stress, above which the stress–optical rule (SOR) begins to be invalid. The critical shear stress of the SOR of this melt turns out to be 5.5 MPa, which is fairly higher than 3.2 MPa at which shear thinning starts, indicating that the SOR is valid up to a point well beyond the incipient point of shear thinning. Furthermore, contrary to conventional wisdom, the breakdown of the SOR turns out not to be correlated with the saturation of chain extension and orientation: It occurs at shear rates well before maximum chain extension is obtained. In addition to the stress and birefringence tensors, we also compare two important coarse-grained second-rank tensors, the conformation and orientation tensors. The birefringence, conformation, and orientation tensors display nonlinear relationships to each other at high values of the shear stress, and the deviation from linearity begins at approximately the critical shear stress for breakdown of the SOR.     

Scaling laws for plasma transport due toη i-driven turbulence

The scale invariance technique has been employed to discuss theη _i-driven turbulent transport under a new fluid model developed by Kimet al [1]. Our analysis reveals that the finite Larmour radius effect plays a decisive role to determine the scaling behaviour of the energy transport under the new fluid model. However, the overall scaling of the transport coefficient remains unchanged as compared to that derived by Connor [2] under the traditional fluid model. The approximations considered by Connor [2] are qualified with additional requirements within the new fluid approach. In the dissipative case, which has not been discussed earlier, additional constraints on the power scaling laws of the transport properties are imposed due to the dissipative mechanisms in the basic governing equations.     

An improved model for noise barriers in a moving fluid

We study a problem of diffraction of a cylindrical acoustic wave from an absorbing half plane in a moving fluid introducing Myers' condition [M.K. Myers, On the acoustic boundary condition in the presence of flow, J. Sound Vibration 71 (1980) 429] and present an improved form of the analytic solution for the diffracted field. The importance of the work lies in the fact that Myers' condition (a generalization of Ingard's impedance condition) is now the accepted form of the boundary condition for impedance barriers with flow and hence yields a correct form of the field. The method of solution consists of Fourier transform, Wiener-Hopf technique and the modified method of stationary phase.     

超高压封垫材料力学性能的测试技术

 本文在现有的压扭法和圆片挤压法测试技术的基础上，提出了理论模型更准确、测试更简便、精度更高的纯内滑移法。在纯内滑移法的测试过程中，封垫材料的塑性变形只发生在试样内部，从而排除了压扭法或圆片挤压法中砧子表面摩擦状态对测试结果的影响。本文采用纯内滑移法研究了叶蜡石在不同焙烧温度和吸湿程度下的力学性能，得出了一些有意义的变化规律。     

固体高分辨~(13)C NMR研究γ线辐照对结晶聚乙稀聚集态结构的影响

结晶聚乙烯(PE)经~(60)Coγ线辐照后,用固体高分辨~(13)C NMR CP/DD/MAS方法观测解析了辐射效果与具有片晶结构的结晶相,结晶—橡胶状无定形界面相以及橡胶状无定形相的聚集态结构的关系。考察了各相中的~(13)C核自旋—晶格弛豫和自旋-自旋弛豫行为及辐照对其影响。得到辐照后产生交联,破坏,相转变及晶型变化等有意义的结果,对PE的辐照效应和机制的探讨提供了核磁共振的新实验证据。     

A sequential technique for the control of traffic intensity in Markovian queues

A sequential parameter control technique previously introduced by the author is modified in this paper so as to make it simple in practice. The detailed procedure involving two phases, a warning phase with control limits and a testing phase using an appropriate test is illustrated for a queueing system with an embedded Markov chain. Operating characteristics of the procedure are also examined.     

BOUNDARY VALUE PROBLEM FOR SECOND ORDER IMPULSIVE DIFFERENTIAL EQUATION

The author employs the method of upper and lower solutions together with the monotone iterative technique to obtain the existence theorem of minimal and maximal solutions for a boundary value problem of second order impulsive differential equation.     

Spectral Characteristics of Edge Electrostatic Turbulence in the HL-2A Tokamak

A three-tip array is used in the HL-2A tokamak to investigate the spectral characteristics of electrostatic turbulence inside the last closed flux surface （LCFS） about 5 cm. Two-point correlation techniques are used to analysis the turbulence structure. It is found that the drift wave turbulence mainly is composed of low-frequency and long wavelength wave packets. The poloidal propagation is mainly in electron-diamagnetic direction, sometimes it propagates in ion-diamagnetic direction, which is influenced by Doppler-frequency shift. The radial propagation velocity is outward and the sizeable fraction of the poloidal velocity, implying that the radial mode plays an important role in the cross field transport.