RAFMs 中厚板TIG 焊下的温度场和应力场研究

应用ANSYS 软件对低活化马氏体/铁素体钢(RAFMs)中厚板多道焊接过程进行三维有限元模拟,将得到的温度场和应力场分别与实验对比,对焊缝区和热影响区宽度进行预测,并通过焊接实验进行验证,同时对焊后的试件进行了金相分析和硬度测试。结果表明：温度场和应力场模拟结果和实测结果基本一致,焊缝区以及热影响区宽度的模拟结果和实测结果基本吻合;采用316L 焊丝填充的焊缝,焊缝与母材熔合较好,焊缝没有明显缺陷;硬度检测呈现：焊缝的硬度大大高于热影响区和母材。     

Selection of certain dichotomous experiments

Summary The problem of allocating a single observation to one of the two available populations is considered. Suppose that a certain characteristic has densityf in one population, and has densityg in the other. On the basis of the value observed, one must specify which population has densityf. It is assumed that when a wrong population is chosen, a certain known loss is incurred. The problem is to allocate the observation so as to minimize the expected loss. General conditions onf andg are derived to decide which population should be selected for taking the observation. Research was supported in part by the National Science Foundation under grant No. SOC79-06386. Work done while on sabbatical leave at Carnegie-Mellon University.     

运用“正交试验法”研制氧化铅防漏抓斗

本文介绍青岛港北港公司运用“正交试验法”在研制氧化铝防漏抓斗方面所做的有益探讨。     

On the suitability of minimum and product operators for the intersection of fuzzy sets

In many papers concerning fuzzy set theory it is assumed that the membership or an element in the intersection of two or more fuzzy sets is given by the minimum of product of the corresponding membership values. To use these operators in modelling aspects of the real world, such as decision making, however, it is necessary to prove their appropriateness empirically. The main question of this study is whether people rating the membership of objects in the intersection of two fuzzy sets behave in accordance with one of these models. An important problem in answering this question is how to measure membership which seems to have the characteristics of an absolute scale. No measurement structure is available at present, but a practical method for scaling is suggested. The results of our experiments indicate that neither the product nor the minimum fit the data sufficiently well, but the latter seems to be preferable.     

浅谈传感器与微机在物理实验中的应用

本简要介绍了传感器、微机的作用,以及将其引入到物理实验教学中的重要性,进而说明了将传感器与微机相结合改革物理实验已是大势所趋。     

经典物理理论中电磁波的传播规律

为了处理波传播的相关问题,引用了麦克斯韦经典理论中波的传播规律.基于麦克斯韦方程组和伽利略变换,利用微分方程来计算不同参考系下同-电磁波的传播.由于介质的运动对波动有重要的影响,所以在多普勒效应中介质的运动也被考虑进来.同时,根据该经典物理理论中的波的传播规律从不同的角度来解释迈克尔逊-莫雷实验的结果.经典物理理论中电...     

Experiment and modeling of exit-selecting behaviors during a building evacuation

The evacuation process in a teaching building with two neighboring exits is investigated by means of experiment and modeling. The basic parameters such as flow, density and velocity of pedestrians in the exit area are measured. The exit-selecting phenomenon in the experiment is analyzed, and it is found that pedestrians prefer selecting the closer exit even though the other exit is only a little far. In order to understand the phenomenon, we reproduce the experiment process with a modified biased random walk model, in which the preference of closer exit is achieved using the drift direction and the drift force. Our simulation results afford a calibrated value of the drift force, especially when it is 0.56, there is good agreement between the simulation results and the experimental results on the number of pedestrians selecting the closer exit, the average velocity through the exits, the cumulative distribution of the instantaneous velocity and the fundamental diagram of the flow through exits. According to the further simulation results, it is found that pedestrians tend to select the exit with shorter distance to them, especially when the people density is small or medium. But if the density is large enough, the flow rates of the two exits will become comparable because of the detour behaviors. It reflects the fact that a crowd of people may not be rational to optimize the usage of multi-exits, especially in an emergency.     

土工织物防护工程反滤准则试验研究

土工合成材料的出现,为岩土工程施工技术带来了重要的影响。但将土工合成材料应用在堤岸防护工程中所出现的一些问题还有进行深入科学研究的必要。尤其是保土性准则一直是研究的热点问题。本文结合较大孔径织造布在堤岸防护工程中多年应用实践,通过室内反滤试验,野外淘刷试验及工程应用实例分析研究,提出了O90≤（2¹0）d90防护工程中织造布保土性设计新准则,突破了目前普遍采用的O90≤（1²）d90设计指标。     

应用型人才为导向的高分子专业中级实验课程设计与探索

为培养应用型高分子人才,本文对高分子专业中级实验课程的设计和选择理念进行探索,通过优化教学课程体系、教学内容,丰富实验教学的内容和模式,建立精品资源共享的高分子实验教学综合平台等多方面进行探索,取得了良好的教学效果。     

夫兰克--赫兹实验装置的优缺点比较与改进

本首先简单论述了夫兰克—赫兹实验的原理,然后分析了两种具有代表意义的实验装置的优缺点。提出了我们的改进方案,给出了依据此方案改进后所获得的实验数据,实验结果表明该改进能较好地提高实验精度并减小误差。