便携式全站仪在钻采井架钢结构安装中的应用

文章介绍了一种由便携机和全站仪组成的便携式全站仪 ,阐述了该全站仪在钻采井架钢结构施工安装过程中的测量工作 ,对测点产生的误差采用伪逆自由网平差方法进行处理 ,控制点的精度可达到± 5mm ,该全站仪具有快速、灵活、准确的特点 ,不仅提高了生产效率 ,而且达到了对资料的计算机化管理。     

Cycle detection using a stack

We present an algorithm for detecting periodicity in sequences produced by repeated application of a given function. Our algorithm uses logarithmic memory with high probability, runs in linear time, and is guaranteed to stop within the second loop through the cycle. We also present a partitioning technique that offers a time/memory tradeoff. Our algorithm is especially well suited for sequences where the cycle length is typically small compared to the length of the acyclic prefix.     

A simple approximation algorithm for the weighted matching problem

We present a linear time approximation algorithm with a performance ratio of 1/2 for finding a maximum weight matching in an arbitrary graph. Such a result is already known and is due to Preis [STACS'99, Lecture Notes in Comput. Sci., Vol. 1563, 1999, pp. 259-269]. Our algorithm uses a new approach which is much simpler than the one given by Preis and needs no amortized analysis for its running time.     

核电站中椭圆柱形屏蔽体辐射衰减率的仿真研究

为了预测核电站中椭圆柱形屏蔽体的辐射衰减率，该文用数值解析法对放射线源到评价点的放射线所穿透椭圆柱形屏蔽物体的交点进行了研究。首先用空间解析法建立了椭圆柱形物体的数学模型。然后解曲面方程求出交点。在判断放射线是否穿透此椭圆柱体时，该文又提出了椭圆柱形屏蔽体的假想外接长方体的建模方法，将曲面方程联立解的复杂计算简化为一次代数方程的简单计算，大幅度地缩短了计算时间。     

A comparison of backpropagation and general regression neural networks in quantative trace metal analysis using anodic stripping voltammetry and cybernetic instrumentation

A comparison is made between backpropagation and general regression neural networks for the prediction of parts per billion lead concentration when used to process data obtained from digested curry powder by the electrochemical analysis method of differential pulse, anodic stripping at a thin film mercury electrode (TFME). Two data sets are used, one requiring the net to classify an unknown analytical data vector into one of a number of previously learnt concentrations, and one requiring the net to predict the probable concentration of an unknown sample by interpolation of the already learnt concentrations. For both of these data sets the general regression neural network is shown to train faster and to provide results superior to those obtained by backpropagation.     

电动自行车充电器自动检测系统设计

介绍了基于PC虚拟仪器和VB环境的电动自行车充电器自动检测系统，阐述了系统检测原理，硬件结构设计及应用软件的编制方法，文中还给出了一个实用的恒流放电电子负载电路。     

偏心渐开线齿轮在高速包装机上的应用

采用偏心渐开线齿轮传动作为高速包装机横封机构，与其它变速传动机构相比，这种机构不仅结构简单，拆装方便，而且速度变化范围较大，传动较平稳，容易进行动平衡。从而能较好地改善封头和切刀的寿命。它最诱人的优点是容易制成可调变速范围的结构，以慢适应不同的物料和包装材料，并且它的制造成本非常低，与普通齿轮传动的制造成本几乎相同。     

捷克5500m^3／min轴流式高炉鼓风机叶片损坏原因及分析

就５５００ｍ＾３／ｍｉｎ高炉鼓风机动，静叶片损坏事故发生的经过以及有关资料，从几个方面详细分析了事故发生的原因。