实时数据仓库中一种改进的数据流更新算法

为实现数据仓库中数据的高效集成,针对数据偏斜分布现象,提出一种改进的数据流更新算法EH-JOIN。该算法对传统散列连接方法进行改进,利用索引将部分频繁使用的主数据存储在内存中,解决了高速数据流下的磁盘频繁访问问题。实验结果表明,与MESHJOIN算法和R-MESHJOIN算法相比,EH-JOIN算法的服务速率在磁盘存储关系集保持适当大小时分别提高了96%和81%,在内存大小不同时提高了57%和48%。     

Development of high-performance liquid chromatography criteria for determination of grades of commercial olive oils. Part I. The normal ranges for the triacylglycerols

Criteria for authentic olive oils were developed from isocratic high-performance liquid chromatography analyses of 99 olive oils from the major Mediterranean producers in the 1983–1986 crop years. Authentic olive oils include extra virgin, virgin and pure or refined oils, but exclude all reesterified and adulterated oils. The extra virgin through pure grades will have a combined area for the LOO (C_18:2C_18:1C_18:1), LOP (C_18:2C_18:1C_16:0), OOO (C_18:1C_18:1C_18:1), POO (C_16:0C_18:1C_18:1), POP (C_16:0C_18:1C_18:1), and SOO (C_18:0C_18:1C_18:1) peaks between 82.0 and 92.6% of the total area (L, linoleic; O, oleic; P, palmitic; S, stearic). Authentic oils will have ratios of LOO/LOP and OOO/POO that coincide with a line defined by OOO/POO=0.7844(LOO/LOP)+0.0968; correlation coefficient is 0.885. Authentic oils will not have a trilinolein (LLL) peak over 0.5% in area. Neither triolein (OOO) nor any other single peak suffices to characterize an olive oil sample as one of the authentic grades.     

大型常压锥顶贮罐的设计

以工程实例为依据，论述国内以往较少采用的大型梁柱式支承锥顶贮罐的结构，介绍了国内外相关设计标准，给出了贮罐的典型结构－斜椽，横梁和立柱的计算公式，并用Excel电子表格编制了计算书。     

脂肪醇生物活性和理化性质的QSAR/QSPR研究

为了研究脂肪醇结构-性质(活性)的定量关系,用相对键长取代拓扑距离,结合距离矩阵,提出了距离调和拓扑指数Te,Te和醇的许多理化性质和生物活性具有良好的相关性.用Te及δ(醇中和羟基相连的碳原子的支化度)与脂肪醇的溶解度、辛醇/水分配系数、急性生物毒性、蒸发热、摩尔磁化率关联,复相关系数分别为0.9955,0.9951,0.9941,0.9964,0.9968,优于文献.同时与脂肪醇的气相色谱保留指数也相关得很好,相关系数为0.9956.结果表明,Te指数可用于醇多种理化性质和生物活性的预测.     

城市污水的层流换热特性理论

为有效利用城市污水热能,以污水源热泵系统中的流动工质——城市污水为研究对象,通过理论分析的方法,对其层流状态下的换热特性进行理论推导和实验验证.结果表明:污水作为热泵的冷热源,有良好的换热特性,推导得出的换热准则关联式h=4.53λ/D,为污水源热泵系统设计提供依据,同时为应用污水余热技术提供理论基础.     

Set methods of left-turn waiting zone at signalized intersection

To maximize the number of vehicles passing by the stop-line in a cycle and improve the operation efficiency of intersection in China,the settlement of left-turn lane waiting-zone is becoming prevailing. Based on conflicting-point method,the internal mechanism of left-turn flow after stopping line was analyzed through taking postposition left-turn lane waiting-zone intersection for instance. The relationship between the first left-turn vehicle and the last vehicle of previous phase passing the conflicting point was expounded. According to the time of successive arriving of two vehicle flows at conflicting-point,the reasonable layout for waiting area of left-turn vehicles was researched when the clearance index was less than 0. The results suggest that the appropriate layout for waiting area of left-turning vehicles can improve the operation efficiency of intersections.     

开封引黄灌区灌溉条件下稻田土壤盐分阈值研究

结合各生育期水稻耐盐度、各处理实际种前初始土壤含盐量和对应生育期最高的土壤含盐量,分析了各灌溉处理条件下的稻田土壤含盐量在水稻各生育期的动态变化规律和允许初始土壤含盐量阈值.结果表明:控制灌溉及控制灌溉加淋洗条件下,各水稻生育期土壤含盐量均有不同程度降低,随着淋洗水量的增加土壤含盐量逐渐降低,并获得了不同灌溉方式下的允许稻田初始土壤含盐量阈值.此结论对实际应用有指导意义.     

企业节能减排的监控系统研究

经济发展与节能减排是一个矛盾的统一体,如何在二者之间进行平衡,考验着中国人的智慧。通过行业分类选取恰当的节能减排指标、采用统计学的基本原理、应用质量控制的技术与方法,提出了节能减排的指标体系和监控方法,以期对节能减排实施动态监控,对我国现阶段的企业节能减排工作有着重要的参考价值。     

石油企业财务风险评价神经网络模型的建立

石油企业财务风险评价是石油行业的重要课题.在确立石油企业财务风险评价指标体系的基础上,建立了基于模糊神经网络的石油企业财务风险评价模型.该评价模型分为模糊量化模块和模糊神经网络(FNN)模块,可根据实际问题进行具体调节,具有学习的功能.经过对200多家石油企业的实证分析,结果表明该模型网络预测误差小,是一种可靠、有效的...     

Computation of concentrations of characteristic atoms of alloys in BCC structure

In this paper,taking Nb-Mo alloy system as an example,the equations of concentration of characteristic atoms of alloys in BCC structure were obtained on the basis of the idea of systematic science of alloys and the number of coordination atoms.The concentrations of characteristic atoms in B2-NbMo type ordered alloys were calculated as functions of ordering degree(s) and composition xMo.When s=smax,the concentrations of characteristic atoms of stoichiometric B2-NbMo intermetallic compound are equal to that o...