基于多元聚类模型与两阶段聚类修正算法的变电站特性分析

变电站负荷包含多种用户负荷,其特性非常复杂,选择单一的日负荷曲线或是用户构成比例作为指标进行聚类,可能忽略其他因素并导致聚类结果不够全面。由此提出了同时考虑变电站日负荷曲线与变电站用户构成的多元聚类模型。为求解该模型,首先对日负荷曲线数据采用Kmeans算法进行聚类。然后,提出一种两阶段聚类修正算法,用于依照变电站用户构成数据修正日负荷曲线聚类结果。研究结果表明,所提方法所得的聚类结果准确度高,可降低聚类结果跌入局部最优的可能性,且所得结果能明确体现各个变电站在日负荷曲线上及用户构成上的差异。     

硅灰对混凝土耐硫酸腐蚀性能试验研究

为了探究硅灰掺量对酸性环境下混凝土耐久性的影响,以一定浓度的硫酸溶液作为腐蚀介质,研究了硅灰掺量分别为0、5％、10％和15％的混凝土试样随腐蚀时间的变化规律.结果表明:随着腐蚀时间的延长,试样均经历从"返霜"到严重破坏的过程,但硅灰的掺入能较好地保持腐蚀过程中试样的完整性;硅灰的掺入可有效减小腐蚀过程中抗压强度的损失...     

电网合环辅助决策软件研究

讨论了以通用关系数据库为后台、图形化界面为人机接口、面向对象的计算为内核的电网合环辅助决策软件，并详细分析了软件的设计，关系数据库设计主要是表类型和表关系的设计。人机界面功能包括网络结构设计模式下添加、更新、删除设备、设备类型、节点名；计算模式下输入实时数据和计算信息进行潮流和复杂故障计算。计算模块采用基本数据类、网络结构类、系统计算类的三层结构，并说明了网络拓扑分析和类的继承、信息流动及实现。     

Scan Worx人体3D测量解决方案及其应用

介绍了来自德国Vitronic公司的3D人体测量系统Scan Worx的系统组成、测量原理和应用功能,并对目前服装企业的应用状况提出了建议。     

沙溪口水电厂计算机监控系统改造

基于沙溪口水电厂计算机监控系统的现状,待改造的LCU较多,短时间不可能全部更换,将改造安排在机组大修期间,通过建立过渡方案,将旧系统LCU依次送至新系统上位机测试,满足要求后一次性接入新系统,最终更换上位机系统,达到新老监控系统平稳过渡,有效提高了系统运行可靠性、稳定性及准确性。     

城市公共绿地开发经营模式探讨

城市公共绿地在城市居民生活中扮演重要角色,然而政府用于建设公共绿地的资金已越来越不能满足社会的需求.所以,笔者从城市绿地开发的概念入手,通过分析总结典型案例,提出几种新的城市公共绿地开发经营模式,发动私人力量,公私联合建设管理城市公共绿地,尽量使城市公共绿地建设与受益相挂钩,减轻政府负担,形成新的符合市场经济发展的开发经营体制.讨论了新的开发模式中政府的职能与义务,提出相应的开发程序,就几个成功案例进行了详尽的分析.     

黔东柏松铅锌矿床矿物特征及地质意义

凯里柏松是黔东地区的代表性铅锌矿床,但研究程度较低。利用矿相显微镜和TIMA对其开展了详细的矿物学研究。结果表明,柏松铅锌矿床矿石矿物主要为闪锌矿、方铅矿和菱锌矿,脉石矿物主要为白云石和少量沥青;矿石具有角砾状、脉状、浸染状、团块状、斑杂状、蜂窝状和星点状构造,以自形、半自形、他形和交代结构为主;围岩蚀变主要为白云石化,其次为沥青化,少量黄铁矿化和方解石化;矿床以硫化矿为主,但近地表的含矿层发生了一定的氧化。矿石及矿物特征表明矿床的形成经历了三个时期,即：在沉积-成岩期发生了成矿物质的预富集作用,在成矿期发生了广泛的热液活动并沉淀了大量的铅锌金属硫化物和白云石,在表生期的近地表环境发生了矿石的氧化作用。该矿床的成矿温度较低,油气有机质可能参与了成矿作用,其属于MVT矿床。该研究有助于指导后期矿产勘查和矿物资源综合利用。     

Reynolds-Averaged Navier-Stokes Equations Describing Turbulent Flow and Heat Transfer Behavior for Supercritical Fluid

Supercritical fluid has been widely applied in many industrial applications.The traditional Reynolds-averaged Navier-Stokes(RANS)equations are directly applied for turbulent flow and heat transfer of the supercritical fluid,ignoring turbulent effect of the thermal physical properties due to the intense nonlinearity.This paper deduces a set of Reynolds-averaged Navier-Stokes equations for supercritical fluid(SCF-RANS equations)to depict turbulent flow and heat transfer of the supercritical fluid taking all the physical parameters as variables.The SCF-RANS equations include many new correlation terms due to fluctuation of the thermal physical properties.Model methods for the new correlation term have been discussed for closing the SCF-RANS equations.Some of them have relatively mature models,while others are completely new and need profound physical theoretical analysis for proposing reasonable models.This paper provides referable information for these new correlations as far as authors know.The SCF-RANS equations not only provide the formulation special for flow and heat transfer of the supercritical fluid,but also represent the most sophisticate form of the RANS equations,for every involved physical property has been considered as variable without any simplification.     

Experimental Investigation on the Effect of Blending Ethanol on Combustion Characteristic and Idle Performance in a Gasoline Rotary Engine

Rotary engine is an ideal electric vehicle range extender.However,the combustion chamber of rotary engine is very narrow and long at the top dead center,which is detrimental to fuel combustion performance.In order to improve its economic and emission performance,this paper built an ethanol/gasoline dual-fuel rotary engine test bench,and the combustion and emission performance of gasoline rotary engine under five ethanol blending ratios were studied.The experimental results showed that,when the fuel pulse width is not adjusted,since the calorific value of ethanol is lower than that of gasoline and the latent heat of vaporization of ethanol is higher than that of gasoline,the addition of ethanol in gasoline lowers the peak pressure.When the ethanol blending ratio reaches 30 vol%,the pressure curve shows a distinct double peak.Under the theoretical air-fuel ratio condition,mixing ethanol in gasoline increases the heat release rate,shortens the combustion duration while prolonging delay period.After blending ethanol,HC,CO and NO_x emissions have been reduced under various operating conditions.Excessive ethanol blending ratio increases NO_x emissions and increases cycle variation coefficient.When the ethanol blending ratio is 15 vol%,it has better power ability while maintaining low cycle variation coefficient and emissions.     

长螺旋压灌扩底桩新施工工艺特点及工程优势浅析

普通钻孔灌注桩在施工过程中常造成倾斜过大、断桩、偏移、钻孔偏斜、桩承载力低、颈缩、孔壁坍塌和孔底沉渣等工程问题。通过对普通钻孔灌注桩施工工艺和长螺旋压灌扩底桩新施工工艺进行对比分析,对长螺旋压灌扩底桩的同步技术、振捣插筋逆作法、特制扩底钻头扩底技术、钻孔成桩一体化和压力灌注进行阐述,总结出长螺旋压灌扩底桩新施工工艺应用于工程中具有成桩质量好、经济性好、单桩承载力高、施工效率高和适用性好等工程优势。