Calculation of current in the Taiwan Strait during summerⅡ. Three-dimensional semidiagnostic and prognostic calculations

The semidiagnostic and prognostic models are used to compute the current in the Taiwan Strait with wind and hydrographic data collected during August, 1984 and September 1 ~ 6, 1988. This calculation can be divided into two stages, i. e. (1 ) the adjustable stage; (2) prognostic calculation. The computed result shows tha the density and velocity fields etc. have been adjusted when t = 2. 5 d, namely the solution of semidignostic calculation is obtained,and the quasi-steady state solution have been reached after about 40 d. Comparing the results of diagncotic calculation with those of semidiagnortic and prognostic calculations indicates that they agree qualitatively. For example, they all have the following common features: (1 ) there is a persistent northward fiow with a volume transport of 0. 8 × 10 6 m3/s through the Taiwan Strait in summer; (2 ) the current near the western coas of Taiwan is stronger than that in other regiona; (3) the upweiling occurs near the Fujian coast and so on. However, there is a quantitative difference between them as follows. For example, the horizotal velocity near the westem cot of Taiwan and the upwelling speed near the Fujian aret both are underestimaed in the diagnestic calculation, because the data used in which is smoothed, and they both are intensified in the solutions of semidiagnostic and prognostic calculations. For example, the maximum velocity near the western coast of Taiwan at t = 0 d (diagnostic), 2. 5 d (semidiagnostic) and 300 d (prognostic) is 59.1, 62. 1 and 62. 0 cm/s, respectively. From the above comparison we see it is quite necessary that a semidiagnostic model be used to compute the currents when the data have been smoothed.

A three-dimensional numerical calculation of the wind-driven thermohaline and tide-induced Lagrangian residual current in the Bohai Sea

On the basis of a three-dimensional weakly nonliear theory of Lagrangian residual current in the Baroclinic shallow seas, a diagnostic numerical calculation of wind-driven, thermohaline and tide-induced Lagrangian residual current in the Bohai Sea is made. The model involves the Richardson number in the eddy viscosity coefficient, wind, thcrmolialine and tidal effects in the focing terms. The runoff of the Huanghe River and a part of the Huanghai Warm Water coming from the Huanghai Sea through the Bohai Sea Strait is also considered. The velocity-splitting method is adopted. The wind-driven circu lation, thermohaline circulation and the tide-induced Lagrangian residual circulation are also obtained individually and analysed. The dynamics of the three main eddies in the Lagrangian mean circulation is discussed. Finally, the numerical result is partly verified with the observed data.

ab initio CALCULATION FOR THE ELECTRONIC STRUCTURE OF GaAs/Al_xGa_(1-x) As SUPERLATTICES: CONJUGATE GRADIENT APPROACH

The electronic structure of GaAs/Al xGa 1-x As superlattices has been investigated by an ab initio calculation method—the conjugate gradient (CG) approach.In order to determine that,a conventional CG scheme is modified for our superlattices:First,apart from the former scheme,for the fixed electron density n(z),the eigenvalues and eigenfunctions are calculated,and then by using those,reconstruct the new n(z).Also,for every k z,we apply the CG schemes independently.The calculated energy difference between two minibands,and Fermi energy are in good agreement with the experimental data.

ab initio CALCULATION FOR THE ELECTRONIC STRUCTURE OF GaAs/AlxGa1-x As SUPERLATTICES: CONJUGATE GRADIENT APPROACH

The electronic structure of GaAs/Al xGa 1-x As superlattices has been investigated by an ab initio calculation method—the conjugate gradient (CG) approach.In order to determine that,a conventional CG scheme is modified for our superlattices:First,apart from the former scheme,for the fixed electron density n(z),the eigenvalues and eigenfunctions are calculated,and then by using those,reconstruct the new n(z).Also,for every k z,we apply the CG schemes independently.The calculated energy difference between two minibands,and Fermi energy are in good agreement with the experimental data.

Calculation of the Duration of the Atomic Tunneling Ionization in a Strong Electrostatic Field by Using Bohmian Trajectories Approach

The duration of a bound electron tunneling through the barrier formed by atomic potential and electrostatic field is calculated by the Bohmian trajectories scheme. The time of the tunneling ionization decreases with the increase of the amplitude of the electrostatic field. By using the information about the position, velocity and force of the Bohmian trajectories, the dynamical process of tunneling through the barrier is investigated.

Integration system research and development for three-dimensional laser scanning information visualization in goaf

An integration processing system of three-dimensional laser scanning information visualization in goaf was developed. It is provided with multiple functions, such as laser scanning information management for goaf, cloud data de-noising optimization, construction, display and operation of three-dimensional model, model editing, profile generation, calculation of goaf volume and roof area, Boolean calculation among models and interaction with the third party soft ware. Concerning this system with a concise interface, plentiful data input/output interfaces, it is featured with high integration, simple and convenient operations of applications. According to practice, in addition to being well-adapted, this system is favorably reliable and stable.

Three-dimensional hydrodynamic model of Xiamen waters

A semi-implicit and Eulerian - Lagrangian finite difference method for three-dimensionalshallow flow has been extended to a more complete system of equations incorporating second-moment turbulence closure model and transport equations of salinity and temperature. The simulation for flooding and drying of mudflats has been improved. The model is applied to Xiamen waters. Based on extensive survey data, water level elevation, temperature and salinity field along the eastern open boundary and at the Jiulong River inlets and runoffs are analyzed, specified and calibrated. The computed results show good agreement with the measured data, reproduce flooding, emergence of large and complex mudflat region.

Slope excavation quality assessment and excavated volume calculation in hydraulic projects based on laser scanning technology

Slope excavation is one of the most crucial steps in the construction of a hydraulic project. Excavation project quality assessment and excavated volume calculation are critical in construction management. The positioning of excavation projects using traditional instruments is inefficient and may cause error. To improve the efficiency and precision of calculation and assessment, three-dimensional laser scanning technology was used for slope excavation quality assessment. An efficient data acquisition, processing, and management workflow was presented in this study. Based on the quality control indices, including the average gradient, slope toe elevation, and overbreak and underbreak,cross-sectional quality assessment and holistic quality assessment methods were proposed to assess the slope excavation quality with laserscanned data. An algorithm was also presented to calculate the excavated volume with laser-scanned data. A field application and a laboratory experiment were carried out to verify the feasibility of these methods for excavation quality assessment and excavated volume calculation. The results show that the quality assessment indices can be obtained rapidly and accurately with design parameters and scanned data, and the results of holistic quality assessment are consistent with those of cross-sectional quality assessment. In addition, the time consumption in excavation quality assessment with the laser scanning technology can be reduced by 70%e90%, as compared with the traditional method. The excavated volume calculated with the scanned data only slightly differs from measured data, demonstrating the applicability of the excavated volume calculation method presented in this study.

Simulation of three-dimensional tension-induced cracks based on cracking potential function-incorporated extended finite element method

In the finite element method,the numerical simulation of three-dimensional crack propagation is relatively rare,and it is often realized by commercial programs.In addition to the geometric complexity,the determination of the cracking direction constitutes a great challenge.In most cases,the local stress state provides the fundamental criterion to judge the presence of cracks and the direction of crack propagation.However,in the case of three-dimensional analysis,the coordination relationship between grid elements due to occurrence of cracks becomes a difficult problem for this method.In this paper,based on the extended finite element method,the stress-related function field is introduced into the calculation domain,and then the boundary value problem of the function is solved.Subsequently,the envelope surface of all propagation directions can be obtained at one time.At last,the possible surface can be selected as the direction of crack development.Based on the aforementioned procedure,such method greatly reduces the programming complexity of tracking the crack propagation.As a suitable method for simulating tension-induced failure,it can simulate multiple cracks simultaneously.

Inductance calculation for 3D microsolenoids with single-layer coils

Three-dimensional(3D) single-layer microcoils have always been a key element for electromagnetic systems;but they lack an easy and accurate method to calculate the inductance value for their complex 3D micro-structures. This paper employed a curve-fitting process to obtain the associated equation for the inductance value and geometric parameters based on the simulation results. The correction factors regarding helical pitch and wire diameter were reviewed,which are used for compensation in the Nagaoka formula. The simulation process numerically simulated the performance of the 3D microcoils using a FEM electro-magnetic-coupled analysis method. Comparison of the simulated inductance value and the Nagaoka formula was undertaken,which shows that the helical pitch and wire diameter contribute a main role in the calculation error. The derived formula was expressed in a concise form to precisely calculate the inductance value of 3D microsolenoids with single-layer coils.

Fast three-dimensional radiation field characterization in largescale nuclear installations

The requirement of the fast three-dimensional radiation field calculation is raised during the decommissioning of large-scale nuclear installations. The most often used methods, such as the Monte Carlo and the discrete ordinates methods, have shortcomings in their simulations of such problems. The coupled Monte Carlo–point kernel computational scheme is developed to meet the requirement. The facility is separated into the source region and the bulk shielding region, with a common interface. The transport within the source region is simulated using the Monte Carlo method, which is by nature good at treating complex geometries. The radiation field in the bulk shielding region is treated by the point kernel approach to avoid the extremely expensive computation for deep penetration problems. The flow rate through the interface,which is given by the Monte Carlo simulation, is considered as the equivalent surface source for the point kernel calculation. Test calculations from simplified typical waste storage facilities have been performed to validate the coupled scheme by comparing them with the results conducted by the Monte Carlo method directly. The good agreement of the results, as well as the significant saving in computing time, indicates that the coupled method is suitable for the fast three-dimensional radiation field calculation.

Three-dimensional elasticity solutions for bending of generally supported thick functionally graded plates

Three-dimensional elasticity solutions for static bending of thick functionally graded plates are presented using a hybrid semi-analytical approach-the state-space based differential quadrature method （SSDQM）. The plate is generally supported at four edges for which the two-way differential quadrature method is used to solve the in-plane variations of the stress and displacement fields numerically. An approximate laminate model （ALM） is exploited to reduce the inhomogeneous plate into a multi-layered laminate, thus applying the state space method to solve analytically in the thickness direction. Both the convergence properties of SSDQM and ALM are examined. The SSDQM is validated by comparing the numerical results with the exact solutions reported in the literature. As an example, the Mori-Tanaka model is used to predict the effective bulk and shear moduli. Effects of gradient index and aspect ratios on the bending behavior of functionally graded thick plates are investigated.

Algebraic Calculation Method of One-Dimensional Steady Compressible Gas Flow

This paper describes a new method of calculation of one-dimensional steady compressible gas flows in channels with possible heat and mass exchange through perforated sidewalls. The channel is divided into small elements of a finite size for which mass, energy and momentum conservation laws are written in the integral form, assuming linear distribution of the parameters along the length. As a result, the calculation is reduced to finding the roots of a quadratic algebraic equation, thus providing an alternative to numerical methods based on differential equations. The advantage of this method is its high tolerance to coarse discretization of the calculation area as well as its good applicability for transonic flow calculations.

Three-dimensional Analysis of Functionally Graded Piezoelectric Plate with Arbitrarily Distributed Material Properties

An orthotropic functionally graded piezoelectric rectangular plate with arbitrarily distributed material properties was studied, which is simply supported and grounded（electrically） on its four lateral edges. The state equations of the functionally graded piezoelectric material were obtained using the state-space approach, and a Peano-Baker series solution was obtained for the coupled electroelastic fi elds of the functionally graded piezoelectric plate subjected to mechanical and electric loading on its upper and lower surfaces. The influence of different distributions of material properties on the structural response of the plate was studied using the obtained solutions.

Three Dimensional Laser Point Cloud Slicing Method for Calculating Irregular Volume

Volume parameter is the basic content of a spatial body object morphology analysis.However,the challenge lies in the volume calculation of irregular objects.The point cloud slicing method proposed in this study effectively works in calculating the volume of the point cloud of the spatial object obtained through three-dimensional laser scanning(3DLS).In this method,a uniformly spaced sequent slicing process is first conducted in a specific direction on the point cloud of the spatial object obtained through 3DLS.A series of discrete point cloud slices corresponding to the point cloud bodies are then obtained.Subsequently,the outline boundary polygon of the point cloud slicing is searched one by one in accordance with the slicing sequence and areas of the polygon.The point cloud slice is also calculated.Finally,the individual point cloud section volume is calculated through the slicing areas and the adjacent slicing gap.Thus,the total volume of the scanned spatial object can be calculated by summing up the individual volumes.According to the results and analysis of the calculated examples,the slice-based volume-calculating method for the point cloud of irregular objects obtained through 3DLS is correct,concise in process,reliable in results,efficient in calculation methods,and controllable on accuracy.This method comes as a good solution to the volume calculation of irregular objects.

THE APPLICATIONS OF A MODIFIED NORMAL FORM APPROACH

The modified normal form approach presented by ZHANG Wei-yi, K Huseyin and CHEN Yu-shu is further extended and a different procedure is introduced which lends itself readily to symbolic calculations, like MAPLE. This provides a number of significant advantages over the previous approach, and facilitates the associated calculations. To illustrate the new approach, three examples are presented.

Efficient Approach for 3D Stationary Optical Solitons in Dissipative Systems

We feature the stationary solutions of the 3D complex cubic-quintic Ginzburg-Landau equation (CGLE). Our approach is based on collective variables approach which helps to obtain a system of variational equations, giving the evolution of the light pulses parameters as a function of the propagation distance. The collective variables approach permits us to obtain, efficiently, a global mapping of the 3D stationary dissipative solitons. In addition it allows describing the influence of the parameters of the equation on the various physical parameters of the pulse and their dynamics. Thus it helps to show the impact of dispersion and nonlinear gain on the stationary dynamic.

Planck’s Oscillators at Low Temperatures and Haken’s Perturbation Approach to the Quantum Oscillators Reconsidered

In the first step the extremal values of the vibrational specific heat and entropy represented by the Planck oscillators at the low temperatures could be calculated. The positions of the extrema are defined by the dimensionless ratios between the quanta of the vibrational energy and products of the actual temperature multiplied by the Boltzmann constant. It became evident that position of a local maximum obtained for the Planck’s average energy of a vibration mode and position of a local maximum of entropy are the same. In the next step the Haken’s time-dependent perturbation approach to the pair of quantum non-degenerate Schr?dinger eigenstates of energy is re-examined. An averaging process done on the time variable leads to a very simple formula for the coefficients entering the perturbation terms.

湿陷性黄土地基中桩基负摩阻力计算新方法

负摩阻力对湿陷性黄土地基中桩基的承载变形性状具有重要影响,现行桩基规范及黄土规范推荐的负摩阻力计算方法不能反映黄土桩基负摩阻力的实际性状。对近30年来在黄土地区开展的钢筋混凝土灌注桩现场浸水试验实测数据进行统计,分析黄土浸水完成后桩身中性点深度、桩身最大负摩阻力深度及负摩阻力系数与桩长径比的关系,通过线性拟合得到了中性点深度比、最大负摩阻力深度比及负摩阻力系数与桩长径比的经验表达式,提出湿陷性黄土地基中桩基负摩阻力计算的新方法。新方法用三角形表示负摩阻力沿深度的分布,能反映负摩阻力从桩顶向下先逐渐增大、达到最大值后随深度增加逐渐减小、最终在中性点处减小为零的分布特征。将提出的方法、桩基规范及黄土规范方法的计算结果与实测结果进行对比,结果表明,桩基规范预测的中性点深度比优于黄土规范,黄土规范预测的最大下拉荷载优于桩基规范,而用新方法计算的负摩阻力最接近实测结果。

ILS进近飞行程序高度损失余度影响因素仿真研究

针对国内飞行程序超障计算准则方面定量研究较少的问题,并为真实反映各类飞机在ILS进近程序中的高度损失(HL)余度数值,本文通过构建飞机着陆—复飞过程的仿真框架,考虑了影响HL值的因素,通过运动学仿真得出ILS进近中不同类别典型航空器的HL值,并与现有飞行程序设计规范中的值进行比较分析。通过模拟计算和结果分析,结果表明使用气压式高度表时,现有规范的公布值与仿真结果较为吻合,但在使用无线电高度表时,现有规范的公布值与仿真结果存在一定差异。