改进遗传算法及其在钻井液设计中的运用

在深井、超深井以及地层复杂等条件下，为了避免或减少钻井事故的发生，达到优质快速钻井的目的，选择合适的钻井液体系至关重要。基于案例推理（CBR，Case-Based Reasoning）的钻井液设计中，钻井液体系由岩性、井型和井深等属性推理得出，但属性权重的分配会对推理结果产生显著的影响；遗传算法在优化属性权重时，存在收敛速度慢、收敛精度低的缺点。针对上述问题，提出一种解决CBR中属性权重分配问题的改进遗传算法。首先，对遗传算子进行改进：选择算子方面，利用指数尺度变换法优化个体选择；交叉算子方面，对算术交叉中的比例因子进行自适应调整；变异算子方面，改进个体变异方向，保持种群多样性。其次，从个体适应度和交叉个体的差异程度两方面实现交叉概率自适应调整。最后，通过对UCI数据集的对比实验，证明了改进后的遗传算法能改善全局收敛性能，提高CBR的准确率。将该算法运用到基于CBR的钻井液设计中，实验结果表明，所提方法能够优化属性权重的分配，进而提高钻井液设计的质量。     

公共图书馆如何吸引读者参与读者活动

近年来,政府加大了对公共图书馆事业的投入力度,公共图书馆不再仅限于传统的图书借还功能,组织举办读者活动已成为图书馆的重点工作. 分析了公共图书馆举办的读者活动引不起读者兴趣的原因,提出了解决这一问题的对策和建议.     

基于培养卓越应用型人才的线性代数问题驱动与案例任务教学模式改革

本文分析了现行线性代数的教学问题,提出了问题驱动与案例任务相结合的教学模式,并以两个案例来说明了此种教学模式的优越性,培养了学生的应用和创新能力,提高了学生的学习兴趣与课堂教学质量.     

O－芳基－苯基硫代膦酰氯和O－芳基－苯基硫代膦酸异硫氰基酯的研究

合成一些新的有机磷化物，组成为（ＡｒＯ）ＰｈＰ（ｓ）Ｙ（Ｙ＝Ｃｌ、ＮＣＳ）．测定了ｍＰ、ＩＲ、ＨＮＭＲ并进行了元素分析．Ｉａ的除草活性尚好．     

管理信息系统教学刍议

企业管理的发展变化和计算机信息技术的迅猛发展,给管理信息系统的教学提出了更高的要求,要求管理信息系统的教学体系要不断完善、教学内容要不断充实,教学方式要不断改进。从预备知识的重要性、教学内容的更新、强化案例教学、加强实践环节等方面进行探讨,探索出一条真正有效、切实可行的教学改革之路。     

Developmental modes of the Neoproterozoic-Lower Paleozoic marine hydrocarbon source rocks in China

Based on the researches on rock type, the mode of occurrence, diagnostic minerals and creatures, the sedimentary geochemistry and organic facies of Chinese marine source rocks from wells and outcrops, and on the research findings of developmental modes of foreign marine source rock, the authors consider that it is impossible to objectively make clear the formation mechanism of hydrocarbon source rock with high organic matter abundance by either single mode of preservation or high organic matter productivity. According to the Chinese geological features, the formation mechanism of the Neoproterozoic-Lower Paleozoic marine source rock is generalized into four modes, namely, thermal water activity-upwelling flow-anoxic; carbonate gentle slope-upwelling flow; xerothermic climate-brine euxinic milieu; and humid climate-retained euxinic milieu; as the Lower Cambrian undercompensation basin organic facies （the Tarim Basin, South China and southwestern margin of North China）, carbonate gentle lime mud bound organic facies （the Upper Ordovician in Tazhong region of the Tarim Basin and the Lower Silurian in the Upper Yangtze Platform）, the Middle Cambrian evaporation laggon organic facies （the Tarim Basin and the Upper Yangtze Platform）, enclosed undercompensation terrigenous bay organic facies （the Middle-Upper Ordovician in the west of the Tarim Basin, the Lower Silurian Long- maxi Formation in the Upper Yangtze platform）. Chinese marine sedimentations with lower organic matter abundance are generalized into two modes of consumption-dilution mode of open epicontinental sea and depletion-dilution mode of supercompensation basin.     

A NEW DESCRIPA NEW DESCRIPTOR OF AMINO ACIDS BASED ON THE THREEDIMENSIONAL VECTOR OF ATOMIC INTERACTION FIELD

QUANTITATIVE STRUCTURE ACTIVITY RELATIONSHIP (QSAR) IS A VERY IMPORTANT TOPIC FOR MANY SCIENTIFIC FIELDS AND CAN BE TERMED AS QUANTITATIVE SEQUENCE ACTIVITY MODELS(QSAM)[1] WHEN REFERRED TO THE RESEARCH ON RELATION- SHIPS BETWEEN STRUCTURES AND ACTIVITIES OF BIOLOGICAL MOLECULES, SUCH AS PROTEINS, AND NUCLEIC ACIDS. HOW- EVER, IT IS VERY DIFFICULT TO ESTABLISH A QSAM MODEL,…     

N-烷基-O-烷基-O-(1,2,2,2-四氯乙基)硫代磷酰胺酯的合成研究

合成了9个未见文献报导的四氯乙基硫代磷酰胺酯,并对它们的合成、结构和性质以及杀蚜虫、线虫活性等进行了初步研究。     

作业成本法对传统成本法的影响分析

介绍了作业成本法的特点,从5个方面探讨了作业成本法与传统成本法的差别,指出作业成本法具有一定的先进性。     

Influence of hydrochlorothiazide on the pain threshold and on the antinociceptive activity of morphine,in rats

Summary Hydrochlorothiazide, acutely injected in rats, has a weak analgesic activity per se and potentiates and prolongs the antinociceptive effect of morphine.This work was supported in part by grants from Consiglio Nazionale delle Ricerche, and by Ministero della Pubblica Istruzione, Roma.