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排序方式: 共有476条查询结果,搜索用时 15 毫秒
1.
Lattice Distortion Analysis Directly from High Resolution Transmission Electron Microscopy Images—the LADIA Program Package 总被引:1,自引:0,他引:1
Direct strain mapping from high resolution transmission electron microscopy images is possible for coherent structures.At proper imaging conditions the intensity peaks in the image have a constant spatial relationship with the projected atom columns.This allows the determination of the geometry of the projected unit cell without comparison with image simulations.The fast procedure is particularly suited for the analysis of large areas.The software package LADIA is written in the PV-WAVE code and provides all necessary tools for image processing and analysis.Image iintensity peaks are determined by a cross-correlation technique,which avoids problems from noise in the low spatial frequency renage.The lower limit of strain that can be detected at a sampling rate of 44 pixels/nm is ≈2%. 相似文献
2.
The distortion structure in nanocrystalline NiAl is studied using molecular dynamics simulation.The rounded grain boundaries in these nanograins are a direct source for the observed lattice distortion.The change of grain size affects directly the volume fraction of the distorted lattice in the nanograin. 相似文献
3.
References: 《计算技术与自动化》2003,22(Z1):54-57
In order to avoid unnecessary damage of electrical equipments and installations,high quality power should be delivered to the end user and strict control on frequency should be made, Therefore, it is important to estimate the power system's harmonic components with higher accuracy. This paper presents a new approach for estimating harmonic component in a power system using secant - fuzzy linear regression method. In this approach the non - sinusoidal voltage or current waveform is written as I linear function. The coefficient of this function is assumed to be fuzzy number with a membership function that has center and spread value. The time dependent quantity is written as Taylor series with two different time dependent quantities. The objective is to use the sample obtained from the transmission line to find the power system harmonic components and frequencies. We used an experimental voltage signal from a sub power station as a numerical test. 相似文献
4.
虚假的会计信息,将严重扭曲股票的价值,扰乱资本市场秩序,侵害投资者的利益。笔者就会计信息失真的原因进行了分析,并就如何防范进行了探讨。 相似文献
5.
Th. Pretorius G. Habedank J. Woitschig F. Vollertsen 《Materialwissenschaft und Werkstofftechnik》2006,37(1):85-91
Thermal treatments of steel components with the goal of hardening often result in distortion by releasing the residual stresses which were brought into the specimen during the preceding processing steps. The goal of the presented work is the minimization of this distortion. By generating definite residual stress fields and investigating the resulting distortion, the distortion mechanism can be observed in detail. A flexible and reproducible way to generate such residual stress fields inside a specimen is by means of local thermal treatment with a laser beam. Computer simulations as well as experiments were carried out using an idealized tooth of a gearwheel (finger sample) as a model system. The deformation of the samples due to the laser heat treatment and the stress fields generated inside the samples were determined with respect to different process parameters. 相似文献
6.
7.
指出会计信息是决策者进行决策的重要依据之一,因此,会计信息的质量,直接关系到决策者的决策及其后续效果.而会计信息失真,将引起投资决策失误和社会经济资源的无效配置.笔者分析了产生会计信息失真的原因及其影响,提出了一些提高会计信息质量的防范措施. 相似文献
8.
Calculated hardenability for improved consistency of properties in heat treatable engineering steels
W. T. Cook P. F. Morris L Woollard 《Journal of Materials Engineering and Performance》1997,6(4):443-448
Hardenability is one of the most important parameters controlling the heat treated properties of engineering steels. It affects
the consistency of response for microstructure, hardness, strength, toughness, and dimensional change (distortion). This study
illustrates that a major benefit of controlling hardenability is improving the consistency of dimensional distortion resulting
from heat treatment. To facilitate the supply of steels to hardenability limits, especially restricted hardenability, a new
technique was developed for the prediction of Jominy hardenability from chemical composition. The technique, termed the “Database
Method,” uses measured Jominy hardenability and chemical composition data, contained in a database, to calculate the hardenability
for a query composition. Using up to ten known steels, selected from the database with compositions closely matching that
of the query steel, a small adjustment is made to the measured hardenability of each known steel allowing for the small difference
in composition between the query and chosen steel. The final calculated result for the query steel is taken as the average
of the various estimates. The basis of the Database Method is explained, and the advantages are illustrated for selecting
engineering grades. 相似文献
9.
Distortion Engineering - Identification of Causes for Dimensional and Form Deviations of Bearing Rings 总被引:1,自引:0,他引:1
Distortion of power transmission parts after heat treatment is influenced by each step of the process chain, ranging from material production to hard-machining. However, an experimental analysis for each production step in the manufacture of bearing rings has shown that distortion is significantly influenced by turning before heat treatment. Elastic ring deformation caused by fixing the workpiece in the chuck leads to a variation of the depth of cut and polygonal form deviations occur after machining. In addition the cutting process induces locally varying residual stresses which also contribute to dimensional and form deviations of machined rings. In this paper results from experimental investigations of the principle physical causes for the distortion of bearing rings are presented and discussed. Finally, strategies for the minimization of distortion are derived. 相似文献
10.
视频拼接技术是计算机图形学和计算机视觉的重要分支,它的发展基于静态图像的拼接技术,但由于视频信息的复杂性,视频拼接也有区别于图像拼接,针对实际运用中的实时拼接的需要,本文提出了一种基于控制帧的固定摄像头视频拼接方法。首先采集控制帧图像,对摄像头进行参数标定获得相机内参和光心坐标,再使用一种改进的畸变矫正方法去除摄像头畸变带来的成像失真。然后对控制帧图像进行SIFT特征提取并进行粗匹配,再用RANSAC的方法剔除误匹配点并拟合出图像变换单应阵。最后使用查表法将各摄像头的图像同步投影到大场景图片上,对重合区域进行光亮补偿和多带融合。最终实现速度可达25帧/秒的实时视频拼接。 相似文献