ABS控制系统数字模型及关键技术研究

我校开发的“ABS控制系统数字模型及关键技术研究”技术日前通过省科技厅组织的鉴定 其针对目前普通运用的以门限值为基础的ABS控制算法中存在的不足 ,从分析汽车制动时单轮受力情况着手 ,提出了基于路面附着系数与控制算法。该方法优点为 :只需测出制动时车轮角速度的变化 ,就可以自动识别路面状况 ,使车轮滑移率控制在最佳值附近 利用该项研究成果 ,可以大幅降低ABS的开发成本和缩短开发周期 经同行专家鉴定 ,基于路面附着系数的ABS控制理论及方法的研究成果在国内处于领先水平 将该技术运用于实车试验 ,将有利开发具有我国自主…     

DTM在工程勘测设计中的应用

论述了地面数字模型DTM(Digital terrain model).结合建筑工程勘测设计(公路选线设计、管道选线设计和土地整平土石方计算等)试验,检核验证了DTM数据的精度和辅助计算程序解算精度.     

拱坝坝肩整体稳定可靠度分析方法探讨

以刚体极限平均理论为基础，首次建立了拱坝坝肩整体稳定可靠度分析数学模型，导出了全概率方法分析其可靠度的计算公式，编写了相应的计算程序，并结合某拱坝实例对两岸坝肩岩体作了较详细的可靠度计算与分析，得到一些有实际意义的成果，实际计算，本文提出的计算方法合理，计算结果可靠，是对拱坝坝肩整体稳定可靠度分析的较好方法。     

Spiral rainband in a numerically simulated tropical cyclone

Spiral rainband is a prominent structure of tropical cyclone. Though its forming mechanism, vortex Rossby wave theory, has been widely accepted in recent years,its internal structural features are still not well known. The spiral rainband in the severe tropical storm Kammuri (2002),which caused heavy rainfall in southeast China, is simulated using the mesoscale model MM5 (V3). Results show that the simulated spiral rainband propagates azimuthally at a speed close to that of vortex Rossby wave in theory, and is accompanied with energy dispersion in the radial direction. The structural features of simulated spiral rainband are analyzed with the high-resolution model output including the full physical process. Positive vorticity, ascending motion, horizontal momentum and so on are highly concentrated in the spiral rainband. The convergent moisture of spiral rainband comes mostly from the planetary boundary layer under 1 km.Airflow from the outside of spiral rainband is convective instability, which can provide instability energy for convection development. However, the atmospheric stratification in the inside of spiral rainband is neutral, implying that the instability energy has been released. There is a mesoscale strong wind band just near the spiral rainband in the outer side with a maximum wind speed exceeding 30 m/s, which results from the pressure force acceleration when the air flows into the spiral rainband along the gradient of pressure.     

Global analysis theory of climate system and its applications

The idea and main theoretical results of the global analysis theory of climate system are briefly summarized in this paper. A theorem on the global behavior of climate system is given, i.e. there exists a global attractor in the dynamical equations of climate, any state of climate system will be evolved into the global attractor as time increases,indicating the nonlinear adjustment process of climate system to external forcing. The different effects of external forcing, dissipation and nonlinearity on the long-term behavior of solutions are pointed out, and some main applications of the global analysis theory are also introduced. Especially, three applications, the adjustment and evolution processes of climate, the principle of numerical model design and the optimally numerical integration, are discussed.     

Conceptual design and RCS performance research of shipborne early warning aircraft

In order to improve the survivability of the aircraft,conceptual design and radar cross section（RCS） performance research are done. The CATIA software is used to design the 3D digital model of the shipborne early warning aircraft, and some measures are taken to reduce the RCS characteristics of the early warning aircraft at the same time. Based on the physical optics method and the equivalent electromagnetic flow method,the aircraft＇s RCS characteristics and strength distribution characteristics are simulated numerically, and compared with the foreign advanced shipborne early warning aircraft. The simulation results show that under the X radar band, when the incident wave pitching angle is 0？, compared with the foreign advanced shipborne early warning aircraft, the forward RCS average value of the conceptual shipborne early warning aircraft is reduced to 24.49%, the lateral RCS average value is reduced to 5.04%, and the backward RCS average value is reduced to 39.26%. The research results of this paper are expected to provide theoretical basis and technical support for the conceptual design and the stealth design of the shipborne early warning aircraft.     

Numerical Modeling of Dendrite Growth in AI Alloys

Dendritic grains are the most often observed microstructure in metals and alloys. In the past decade, more and more attention has been paid to the modeling and simulation of dendritic microstructures.This paper describes a modified diffusion-limited aggregation model to simulate the complex shape of the dendrite grains during metal solidification. The fractal model was used to simulate equiaxed dendrite growth.The fractal dimensions of simulated AI alloy structures range from 1,63-1.88 which compares well with the experimentally-measured fractal dimension of 1.85; therefore, the model accurately predicts not only the dendritic structure morphology, but also the fractal dimension of the dendrite structure formed during solidification,     

Control of coupling among three major factors for formation of high-efficiency gas reservoir A case study on the oolitic beach gas reservoir in Feixianguan Formation in the northeast Sichuan Basin

Through a case study of the high-efficiency gas reservoir in Feixianguan Formation in the northeast Sichuan Basin, quantitative and semi-quantitative analyses of key elements such as hydrocarbon generation, migration and accumulation, and reservoir evolution as well as their interplay in the critical moment of reservoir formation controlled by the energy field were carried out, by means of numerical modeling of the energy field. It was found that the climax time for Permian hydrocarbon generation was Late Triassic-Early Jurassic and accumulation of oil and gas has resulted in large-scale paleoreservoirs in paleostructural traps in Feixianguan Formation, a process facilitated by fractures connecting the sources. The paleoreservoirs have been turned into high-efficiency gas kitchens due to pyrolysis, which resulted from deep burial at a temperature of 170-210℃ as induced by tremendously thick sedimentation in the foreland basin of Daba Mountain in Late Jurassic-Cretaceous period. Meanwhile, abundant acid gas like H2S produced from thermo-chemical sulfate reduction （TSR） at high temperatures leads to extensive dissolution of dolostone in the paleoreservoirs, which may in turn result in modification of the reservoirs and preservation of the reservoir rock porosity. The present distribution of gas reservoirs was ultimately determined in the processes of adjustment, cooling and decompression of the paleoreservoirs resulting from intense deformation in the front of Daba Mountain during the Himalayan orogeny.     

基于双线性插值模型的高程异常值的获取

以已知的离散数据点坐标和高程异常为研究对象,讨论了基于双线性内插模型的高程异常值获取的方法,通过内插模型建立高精度、高分辨率的区域高程异常数字模型,从而内插出该区域内任何一点或一小片区域的高程异常值,有助于解决各种与大地水准面相关的测绘工程问题,对推动“数字区域”、“数字城市”、“数字中国”的信息化建设具有重要作用.