A united model of diametral error in slender bar turning with a follower rest

Follower rest is an essential accessory for turning machines during the manufacture of slender bar. In order to analyze the effects of the follower rest and other machining conditions on diametral error, a united model is developed for predicting diametral error of slender bar. The proposed model consists of three components: geometric analysis of diametral error, finite element model of workpiece deflection and statistical model of cutting forces. Since there is a coupling between the actual depth of cut and the cutting force, a computer program is developed to determine the coupled depth of cut by using dichotomy. Then, a series of experiments are carried out to verify the prediction accuracy of the proposed model and a good agreement between the predicted and measured data is found. Finally, a series of numerical examples are calculated to analyze some important factors influencing diametral error of slender bar. The results show that the diametral error mainly depends on the location of follower rest, depth of cut and feed rate. But the cutting speed only has a slight effect on the diametral error.     

Parallel construction of SLR (1) and LALR (1) parsers

The generation of an LR parser consists of constructing a parse table, with one row per state (in a push-down automaton), and one column per terminal symbol. Traditionally, this is carried out row by row, with the computation of one row depending (potentially) on all the others. We present a technique for carrying out the lookahead computation of SLR (1) and LALR (1) parsers in a completely parallel fashion. Our technique performs the computation by column, rather than by row. We show that the computation is totally independent for each column, making it ideal for parallelization. The speedup factor of the technique is min (N, T), whereN is the number of processors andT is the number of terminal symbols in the user's grammar.     

形式与功能的随从及互动——金叶商厦的设计尝试

通过在金叶商厦的设计中建筑表现出的形式与功能的随从及互动关系，探索建筑创作形式美的原则取向。     

K0固结条件对上海软土强度和变形影响的试验研究

本文通过对上海淤泥质粉质粘土和淤泥质粘土,在K_0固结条件下的常规三轴和真三轴排水剪切试验,探讨了K_0固结状态对上海软土强度和变形性能的影响规律,并与各向等压固结三轴排水剪切试验的情况进行了比较和分析。     

SPD型式试验对外部脱离器的要求

引用IEC 61643.11-2011《Low-voltage surge protective devices - Part 11： Surge protective devices connected to low-voltage power systems-Requirements and test methods》最新试验标准的内容,分析、阐述脱离器在SPD型式试验中的动作负载试验、热稳定性试验、短路电流特性试验和低压,以及高压故障引起的TOV试验要求和程序,以正确了解外部脱离器的功能、选择和应用。     

内外空间的交融与共享--浅析玉溪师范附属中学教学楼、实验楼设计

在比较复杂和紧张的基地条件下,如何解决玉溪师附中教学楼及实验楼的使用功能,组织学生人流并创造良好的园林式的校园空间环境,为学生提供休息、交往的室外空间,是我们值得研究的问题。     

内外空间的交融与共享--浅析玉溪师范附属中学教学楼、实验楼设计

在比较复杂和紧张的基地条件下,如何解决玉溪师附中教学楼及实验楼的使用功能,组织学生人流并创造良好的园林式的校园空间环境,为学生提供休息、交往的室外空间,是我们值得研究的问题。     

GBF高强薄壁管无梁楼盖施工技术探讨

针对高强薄壁管混凝土振捣不密实、GBF管上浮及位移、易损坏的质量通病,阐述了GBF管现浇混凝土空心楼盖施工工艺和施工要点,并提出了施工控制措施,从而有利于该技术的推广应用。     

热电偶测温的微机补偿

为了提高热电偶测温的精度，利用ＡＤ５９０温度传感器对冷端温度进行动态测定，再根据热电偶分度表获得冷端补偿电势值，然后在微机内与热电偶实际输出电势进行代数迭加，通过热电偶分度表，便可由该代数和换算出实测温度。该补偿法在对海军某舰柴油机排气温度的测定中，取得了较高精度，达到了自动补偿和动态显示的目的     

双栅低能电子积分谱仪的实验研究

结合电子中微子质量测量研制高分辨率β谱仪的需要,我们开展了低能电子减速积分谱仪的实验研究。减速积分谱仪已出现多年了。五十年代哈密顿,六十年代卡德维尔,以及七十年代的赫契托等都曾作过减速栅型谱仪的工作。他们所用都是双层球栅分析栅网。赫契托用了每毫米四线的32°张角的球面栅,透射率达20%,对于200—1400eV的电子分辨率为0.06%。但前人所研究谱仪都是能量极低(2 keV以下)、尺寸较小的。为了适应中微子质量测量的要求,我们在较高能区作了实验研究。