三峡库区湖北四县水土资源综合开发利用与水土流失防治对策研究

三峡库区湖北宜昌、秭归、兴山、巴东四县幅员面积１１５８９．３平方公里，总人口数１６６．０２万人，三峡水库形成后，淹没土面积７４．４７平方公里，涉及８．９４万人，规划农业生产安置２．８万人。本文以四县土地资源利用现状主和环境容量的分析为基础，进行三峡库区移民安置对水土流失的影响评价，论证综合开发利用水土资源，水土保持与开发性移民相结合，是扩大库区人口环境容量的必由之路，研究制订出移民安置与水土资源的     

一种辐射源距离的估算方法

提出利用测量设备与辐射源相对运动速度及测量设备所接收到的辐射功率的估算测量设备到辐射源距离的一种方法。对计算精度进行了分析，通过算例对理论分析进行了检验。     

Optimal Solutions for the Temporal Precedence Problem

Abstract. In this paper we refer to the Temporal Precedence Problem on Pure Pointer Machines . This problem asks for the design of a data structure, maintaining a set of stored elements and supporting the following two operations: insert and precedes . The operation insert (a) introduces a new element a in the structure, while the operation precedes (a,b) returns true iff element a was inserted before element b temporally. In [11] a solution was provided to the problem with worst-case time complexity O (log log n ) per operation and O(n log log n) space, where n is the number of elements inserted. It was also demonstrated that the precedes operation has a lower bound of Ω (log log n ) for the Pure Pointer Machine model of computation. In this paper we present two simple solutions with linear space and worst-case constant insertion time. In addition, we describe two algorithms that can handle the precedes (a,b) operation in O (log log d ) time, where d is the temporal distance between the elements a and b .     

某微型起爆器引起的一起误爆事故分析

该文分析某微型起爆器引起的一起误爆事故，指出该起爆器设计上的缺陷及其对作业安全的威胁，提出防患建议。     

最佳基数排序

基数排序由于其效率高而被广泛应用。通常,基数排序所用的基数是10,然而,如果求得一个基数r_(best),并且用r_(best)为基数进行基数排序使排序时间达到最小,则这将具有非常重要的意义。本文给出了求r_(best)的方法,分析了以r_(best)为基数进行基数排序的时间复杂度,提出了进一步提高效率的措施,并将以r_(best)为基数的基数排序速度与以10为基数的基数排序进行了比较。     

提高大直径井眼机械钻速的几项措施

随着我国西部地区石油勘探开发的进展，5000－7000m的深探井所钻数量不断增多，套管程序增加，特别是大尺寸井眼所钻深度明显加大。由于国产大尺寸钻头结构单一、型号少，破岩机械能量和水力能量不足，在易斜井段目前尚无可靠的防斜保直措施，以及钻井液性能不适宜等原因，大尺寸井眼的钻这远远低于215．9mm井眼的钻速。据此，提出了几项可以提高大尺寸井眼钻速的措施：增加大尺寸钻头的种类，采用阶梯式扩眼钻头，强化钻井参数和水力参数，选用中速动力钻具，改善钻井液性能以及采用冲击旋转钻具等。     

Computational complexity of queries based on itemsets

We investigate determining the exact bounds of the frequencies of conjunctions based on frequent sets. Our scenario is an important special case of some general probabilistic logic problems that are known to be intractable. We show that despite the limitations our problems are also intractable, namely, we show that checking whether the maximal consistent frequency of a query is larger than a given threshold is NP-complete and that evaluating the Maximum Entropy estimate of a query is PP-hard. We also prove that checking consistency is NP-complete.     

抚河流域水生态环境恢复措施初探

简述江西省抚河流域的概况、水生态环境的现状及存在的问题.包括淤泥的堆积、水土的流失、水污染、沿岸圩堤的防洪标准普遍偏低等.并对这些问题提出了流域水生态环境恢复的目标,针对抚河流域水生态环境的恢复目标提出了水权分配、水土保持治理、水工程治理、水质治理等方面的一系列初步的措施与建议.