Acoustic radiation force of an incident cylindrical diverging wave exerted on a multilayered sphere is theoretically and numerically studied. Based on sound scattering theory, a closed-form of the acoustic radiation force is obtained and several numerical simulations are provided. It shows unexpectedly that the radiation force becomes negative at selected values of ka and kr₀ in a cylindrical diverging progressive wave (where k is the wave number, a is the sphere's radius and r₀ is the distance of the sphere from the acoustic source). As kr₀ increases to infinity, it degenerates to the case of a plane wave field. Relative thickness of layer affects both magnitude and position of the resonant peaks for a two-layered sphere while it does not significantly affect those for a three-layered sphere. As the innermost layer is substituted by the air, the resonant peaks become more pronounced due to the large difference of acoustic impedance. This study is expected to provide a theoretical basis to develop a new generation of acoustic tweezers using a single beam of progressive waves, which has potential applications in biomedical ultrasound and material sciences.

Ballistic performance of single-material-gate and triple-material-gate graphene nanoribbon field effect transistors (GNRFETs) with various doping profiles is studied in a quantum kinetic model based on non-equilibrium Green's functions (NEGF) solved self-consistently with Poisson's equations.It shows that triple-material-gate GNRFET with linear doping (TL-GNRFET) exhibits significant advantage in reducing SCEs and DIBL effects,as well as achieving better subthreshold slope and better on/off current ratio.In addition,asymmetric gate underlap is also discussed.It is revealed that as top and bottom gates are both shifted towards source on/off state current performance is improved.

A theoretical model of the temperature field and infrared radiation field is presented,the physical characteristic of which is the separate treatment of the three wavelength regions of the radiation of the sun,the sea and atmosphere background,and the target,and based on the model the complete set of equations of the temperature field and radiation field for the ship in question are obtained that are then used to developed a computer software to obtain the field distribution and to simulate the thermal images of the target.The flow chart of the software is presented and key points concerning the programming are discussed.The numerical results and the simulated graphs for the infrared images of a ship are calculated using the software.The results are compared with the real infrared images of the ship and the main features of the two results are in good agreement.

For the computation of saturated-unsaturated water table flow, a kind of difference scheme of irregular convex polygon mesh is developed. Using this method, saturated-unsaturated seepage flow is calculated to AKAI's sand model and KOM-ADA's reservoir model. The results obtained here are compared with results ob -tained from computations in which rectangled difference meshes were used. The applicableness and accuracy of this method are also discussed.

For saturated-unsaturated water table flow, computations of ADEP, ADIP and implicitly alternating direction iterative procedure are made and compared.The i-terations are not convergent and computational results are strongly distortional Based on supplementing a particular term, a kind of completely implicit and altern-ting direction iterative procedure is given The relative results for computational model of different scales are satisfactory. Problems of how to give the particular supplemental term and how to select better parameters are discussed, the computational results are given.

The implicit alternating-direction-iteration method is used to solve question of saturated-unsaturated seepage flow under rapid change of the water surface level. The numerical.results of Akai model are given and compared with experimental results.It is found that the numerical results given in this paper are in good agreement with experimental results and better than results by finite element method.The numerical results of komada model are close to results by finite element method.