单电极直流电弧炉电热特性理论研究

运用电磁理论与流体静压力原理,导出了电弧自身的电磁向心压缩力以及电弧对熔池冲力的解析式。又运用辐射传热原理,导出了单电极电弧对熔池与炉衬辐射传热的解析式。解析式揭示出电弧自身电磁向心压缩力、电弧对熔池冲力,单电极电弧对熔池以及对炉衬辐射传热的规律。     

一种基于数字水印的错误检测和定位技术

为了增强视频通信系统在有误码信道的适应能力 ,提出了一种基于数字水印技术的错误检测方法 ,使得解码器可以对误码块进行有效的补偿。其原理为编码器在量化后离散余弦变换 (DCT)系数中嵌入易碎的数字水印 ,解码器可以通过提取水印从而确认错误以及错误发生的首宏块位置。仿真结果证明 :在信道误码率为 5× 10 - 4时 ,与常用的基于语法的方法相比 ,本方法的错误检测率是其的 1.32～ 1.82倍 ,错误正确定位率是其的 2 .95～ 5 .32倍 ,而且 PSNR只有微弱降低 ,同时算法复杂度很低     

Simulation and Experimental Analysis of Super High-Speed Grinding of Ductile Material

This study aims to reduce the work-affected layer of the machined surface by carrying out the grinding at the speed over static pr o pagation speed of plastic wave of ductile materials and also aims to clarify suc h super high-speed machining mechanism.This paper reports on the result obtain ed through the molecular dynamics simulations and experiments on the super-spee d grinding below and beyond static propagation speed of aluminum.From the simul ation results,it is verified that the plastic deformation ...     

The detection of structural deformation errors in attitude determination

In the determination of the attitude parameters from a multi-antenna GPS array, one of the major assumptions is that the body frame is rigid at all times. If this assumption is not true then the derived attitude parameters will be in error. It is well known that in airborne platforms the wings often experience some displacement during flight, especially during periods of initializing maneouvres, such as taking off, landing,and banking. Often it is at these points in time that it is most critical to have the most precise attitude parameters.There are a number of techniques available for the detection of modeling errors.The CUSUM algorithm has successfully been implemented in the past to detect small persistent changes. In this paper the authors investigate different methods of generating the residuals, to be tested by the CUSUM algorithm, in an effort to determine which technique is best suited for the detection of structural deformation of an airborne platform. The methods investigated include monitoring the mean of the residuals generated from the difference between the known body frame coordinates, and those calculated from the derived attitude parameters. The generated residuals are then passed to a CUSUM algorithm to detect any small persistent changes. An alternative method involves transforming the generated residuals into the frequency domain through the use of the Fast Fourier Transform. The CUSUM algorithm is then used to detect any frequency changes. The final technique investigated involves transforming the generated residuals using the Haar wavelet. The wavelet coefficients are then monitored by the CUSUM algorithm in order to detect any significant change to the rigidity of the body frame.Detecting structural deformation, and quantifying the degree of deformation, during flight will ensure that these effects can be removed from the system, thus ensuring the most precise and reliable attitude parameter solutions. This paper, through a series ofsimulations, will assess the effectiveness of the above mentioned techniques for detecting structural deformation effects on a GPS multi-antenna array. These principles are then tested with experimental data.     

区分全同粒子的力学量

给出可以区分两个(或两个以上)全同粒子的情况和区分方法,从而给出更具有操作性的全同性原理     

小区暖气失调原因调查和改造方案的实施

通过对镇苑小区采暖情况的跟踪调查及数据采集，找出了供暖系统不热的原因，据此对系统进行了针对性的改造，取得了良好的改造效果。     

火力发电厂高温过热器爆管分析

针对广州发电厂3号锅炉高温过热器发生爆管的情况，通过化学成分分析、力学性能试验和金相检验，认定原管子材质符合设计要求。在金相检验中，发现爆管处存在大量蠕变孔洞及裂纹，从而判定此次爆管是在高温和外弧切向最大拉应力作用下引起的蠕变脆性断裂造成的。     

A new model for the life prediction of GH4133 under TMF conditions

Thermal mechanical cyclic strain tests were carried out under in-phase and out-of-phase conditions on a Nickel-base Superalloy GH4133 in the temperature range of 571-823℃. Based on analyzing the present models of TMF (thermal mechanical fatigue) life prediction, a new model for predicting nickel-base superalloy TMF lifetime was proposed.TMF life of superalloy GH4133 was calculated accurately based on the new model. Experimental TMF life has been compared with the calculatedresults and all results fall in the scatter band of 1.5. The calculating results show that the new model is not only simple, but also precise. This model will play great roles in life prediction of the metal materials and the engineering components subjected to non-isothermal service conditions.     

高低杠“屈体腾越转体180°再握”动作的运动学分析

本文采用固定高速摄影及影片数字化研究方法，对山西体操运动员郭佳在１９９０年新创的屈体腾越转体１８０°再握动作进行运动学分析，得出各技术环节的运动学数据，找到其动作的运动学特征，为我国体操教练员和运动员提供参考。     

铅溴络合物极谱吸附波的研究

本文研究了铅溴络合物在高氯酸－磷酸－草酸介质中的极谱行为。确定底液组成为５％ＮａＢｒ－１１％ＨＣｌＯ４－５％Ｈ３ＰＯ４－０．８％Ｈ２Ｃ２Ｏ４。工作曲线线性范围为０－１５０μｇ／５０ｍｌ检测下限达０．０１μｇ／ｍｌ体系选择性好，应用于实际样品的测定，获得满意结果。