Digital Number的数学表达问题

Digital Number(DN)是信息科学关于信息采集的术语,需要界定和理顺DN各方面的关系,解决DN在遥感技术、数学、计算机科学的表达问题。阐述DN基本认识及其应有常态,给出DN名称和DN含义,梳理DN来源及其演变,明确DN与模拟量关系、DN与数值关系及DN与非DN界限,陈述数字结构、数字标识及不同系统层面DN,形成10方面正面共识,供分析对照。对DN表达问题归纳为DN代表关系、技术关系、数学关系、数值关系、标识关系5种类型,分析这些相应关系的表达缺陷,对DN有关方面做表达示范。创新成果:界定DN与模拟量关系;归纳DN的感性错误与其错误导向关系;重新解释数值及数值类型,对数值做定义,数值类型应包括DN分支,数值应包括DN来源成员;完善DN、数值及非数值式中参数的相应描述;规范数字术语在数字技术及数学的使用。达到提高DN及其关联的认识,促进数学的发展,利于消除遥感技术、数学、计算机科学出现的DN各种表达问题。

注册表及其管理类的开发和设计

在Windows操作系统中注册表是操作系统管理和控制硬件、软件、用户环境及Windows界面的一套多种类型数据文件组成的信息数据库,对整个系统安全、有效地运行起着至关重要的作用。介绍了注册表的产生、演进过程、数据存储以及作用、功能和结构,并通过编程实例,阐述管理注册表实用类的开发和设计方法。

VCL Framework的演化-VCL.NET 生命总会寻找到出路!

在.NET 平台上运行以 VCL 为基础撰写的应用程序,这将是一件多么奇妙的事情。是的,它即将变为现实。Borland 的工程师正在将VCL.Framework向.NET上进行移植。你将会在 Delphi 8上见到它。

A numerical study on the generation of a distinct type of nonlinear internal wave packet in the South China Sea

A distinct type of nonlinear internal-wave packet, with the largest internal solitary wave in the middle of the packet, was regularly observed in the South China Sea during the Asian Seas International Acoustics Experiment in 2001. Data analysis shows that the occurrence of the distinct internal wave packet is closely related with the occurrence of lower-high internal tides; the internal tides are mixed in the experimental area and, thus, there is diurnal inequality between the heights of two neighboring internal tides. Modeling of internal tides and internal solitary waves in a shoaling situation suggests that this type of wave packet can be generated in the South China Sea by the large shoaling of internal solitary waves and internal tides. Both the internal solitary waves and the internal tides come from the direction of Luzon Strait. The initial large internal solitary waves contribute to the occurrence of the largest internal solitary wave in the middle of the packet and the waves behind the largest intemal solitary wave, while the shoaling internal tides bring about the nonlinear internal waves in front of the largest internal solitary wave via interaction with the local shelf topography.

Variation in the temperature field of rocks overlying a high-temperature cavity during underground coal gasification

High temperature affects rocks in a way that changes the physical and mechanical properties of them. The temperature field in rock overlying a high temperature zone has been estimated using experimental research on thermal conductivity of the overlying strata. Numerical analysis software was used to esti- mate rock thermal conductivity at different temperatures. These estimates were then used with COMSOL Multiphysics to perform a numerical analysis with the heat conduction model. The results show that rock thermal conductivity decreases as the temperature increases and that various lithologies show similar behavior. The thermal conductivity of each rock type differs from the others at a given temperature. Exact values for the temperature distribution in the overlying strata during the process of underground coal gasification are obtained from the numerical simulation. The temperature in the rock changes with the height and direction from the gasifier. Temperature gradients vary for different types of rock. This result provides an important reference for further study of the strength of overlying strata subject to the process of underground coal gasification.

Numerical verification of similar Cam-clay model based on generalized potential theory

From the mathematical principles, the generalized potential theory can be employed to create constitutive model of geomaterial directly. The similar Cam-clay model, which is created based on the generalized potential theory, has less assumptions,clearer mathematical basis, and better computational accuracy. Theoretically, it is more scientific than the traditional Cam-clay models. The particle flow code PFC3 D was used to make numerical tests to verify the rationality and practicality of the similar Cam-clay model. The verification process was as follows: 1) creating the soil sample for numerical test in PFC3 D, and then simulating the conventional triaxial compression test, isotropic compression test, and isotropic unloading test by PFC3D; 2)determining the parameters of the similar Cam-clay model from the results of above tests; 3) predicting the sample's behavior in triaxial tests under different stress paths by the similar Cam-clay model, and comparing the predicting results with predictions by the Cam-clay model and the modified Cam-clay model. The analysis results show that the similar Cam-clay model has relatively high prediction accuracy, as well as good practical value.

Numerical simulation investigations of energy-saving diffuser of main fan

Based on the boundary condition of field engineering, numerical simulations of28 conditions of existing diffusers of 3 structure types were investigated by ComputationalFluid Dynamics software package, and there were the problems of larger structure resistanceand lower diffusing efficiency of these diffusers by analysis of CFD results.Thestructure outlines of the energy-saving diffuser were constructed by the application ofstream function and potential function superimposing.On the basis of numerical simulationsof energy-saving diffusers of 5 area-enlarging ratios, structural resistances and diffusingefficiencies of 5 energy-saving diffusers were comparatively analyzed, and therange from 2.00 to 2.31 of the rational area-enlarging ratio of energy-saving diffusers wasderived.The optimization area-enlarging ratio of the energy-saving diffuser was presently2.28 through comparable analysis.From the above, the results show that the coefficient ofperformance of the energy-saving diffuser is better than 3 existing diffusers.

Random seismic noise attenuation by learning-type overcomplete dictionary based on K-singular value decomposition algorithm

The transformation of basic functions is one of the most commonly used techniques for seismic denoising,which employs sparse representation of seismic data in the transform domain. The choice of transform base functions has an influence on denoising results. We propose a learning-type overcomplete dictionary based on the K-singular value decomposition( K-SVD) algorithm. To construct the dictionary and use it for random seismic noise attenuation,we replace fixed transform base functions with an overcomplete redundancy function library. Owing to the adaptability to data characteristics,the learning-type dictionary describes essential data characteristics much better than conventional denoising methods. The sparsest representation of signals is obtained by the learning and training of seismic data. By comparing the same seismic data obtained using the learning-type overcomplete dictionary based on K-SVD and the data obtained using other denoising methods,we find that the learning-type overcomplete dictionary based on the K-SVD algorithm represents the seismic data more sparsely,effectively suppressing the random noise and improving the signal-to-noise ratio.

高压冶金技术在高氮钢冶炼中的应用

随着经济的发展,我国高压冶金技术呈现出了裹挟之势,不仅整体技术得到了有效的升级,技术实际应用领域也逐渐扩展。文章首先对高氮钢冶炼项目的背景进行了分析,并阐释了高压冶金数理模拟类型,以试验为基础着重分析了高压冶金技术在高氮钢冶炼中的应用参数,旨在为技术人员提供有效的数据信息。

New Double Integrals Weighted Cebysev Type Inequalities

In the last years, the theory of integral inequalities are playing a very significant role in all fields of mathematics, many monographs have been devoted to this subject and present a very active and attractive field of research, the applications of integral inequalities have known a great development in many branches of mathematics in statistics, differential equations and numerical integration, The aim of this paper is to establish new extension of the weighted montgomery identity for double integrals then used it to establish new t^eby^evtype inequalities.

Numerical simulation of the effect of lower positive charge region in thunderstorms on different types of lightning

Combined with the existing stochastic lightning parameterization scheme, a classic tripole charge structure in thunderstorms is assumed in the paper, and then 2-dimensional fine-resolution lighting discharge simulations are performed to quantitatively investigate the effect of lower positive charge(LPC) on different types of lightning. The results show:(1) The LPC plays a key role in generating negative cloud-to-ground(CG) flashes and inverted intra-cloud(IC) lightning, and with the increase of charge density or distribution range of LPC region, lightning type changes from positive polarity IC lightning to negative CG flashes and then to inverted IC lightning.(2) Relative to distribution range of charge regions, the magnitude of charge density of the LPC region plays a dominant role in lightning type. Only when the maximal charge density value of LPC region is within a certain range, can negative CG flashes occur, and the occurrence probability is relatively fixed.(3) In this range, the charge density and distribution range of LPC region jointly determine the occurrence of negative CG flashes, which has a linear boundary with the trigger condition of IC lightning.(4) The common effect of charge density and distribution range of the LPC region is to change the distribution of positive potential well of bottom part of thunderstorms, and inverted IC lightning occurs when the initial reference potential is close to 0 MV, and negative CG flashes occur when the initial reference potential is far less than 0 MV.