Managing Water to Minimize Risk in Tailings Storage Facility Design,Construction, and Operation

Mine Water and the Environment - Reducing the amount of water in a milled tailings storage facility (TSF) is the primary way to reduce the risk of a catastrophic failure. In addition, a significant...     

酰胺型梳状聚羧酸类高效减水剂的制备及性能研究

采用溶液聚合,将改性后具有丙烯酰胺基团的聚醚单体与(甲基)丙烯酸类单体进行共聚,并通过红外光谱和凝胶渗透色谱表征其结构、分子量及其分布,其主链与支链通过酰胺/酰亚胺键相连接.采用动态光散射法测定共聚物的流体力学直径,酰胺型聚羧酸的DH比普通聚羧酸大.水泥净浆流动度试验表明该聚羧酸高效减水剂具有很好的分散性和保坍性,满足高性能混凝土的要求.     

上海环球金融中心结构设计简析

上海环球金融中心是一座多功能、先进智能型的摩天大厦，建成后总高度达492米，为世界第一高楼。设计建造这一超级摩天大厦是一项复杂的系统工程，尤其在结构设计方面，如何选用最有效的结构体系，如何建立完善的计算模型，以及如何进行全面的计算分析都是结构设计的关键问题。本对上海环球金融中心的结构设计及施工方案进行了较全面的介绍。     

Simulation of free-surface flow using a boundless grid

Physically based fluid simulation in recent years has been successful for small-scale fluids such as liquid in a cubic cavity.However,for boundless free-surface flow of large scale and irregular area,there is a critical trade-off between simulation efficiency and accuracy because of the restriction of the traditional regular computational grids.This paper introduces boundless computational grids based on hierarchical runlength encoding to simulate large-scale free-surface flow.We first modeled the free-surface flow with a lattice Boltzmann method,and calculated the surface curvature in the update process.We then introduced an effective method with which to calculate the surface curvature according to the surface tension so that the surface detail was enhanced,and obtained the curvature of each surface effectively as it was extracted.Furthermore,we dynamically compressed and indexed the computational cells with the improved hierarchical run-length encoding algorithm,so that the grid expands dynamically according to the fluid flow and the computational resources used were proportional to the volume of the fluid.Finally fluids in different situations were simulated realistically.The proposed method makes the best of the computational resources to perform the simulation with high resolution,and dynamically allocates resources so that the fluid can expand in random directions without boundaries,which is suited to the simulation of large-scale visual scenes.     

润滑油污染因素的分析

以柴油机润滑油为例,通过分析其污染的过程,建立了柴油机润滑油污染程度的数学模型,并对润滑油被污染的影响因素进行了分析研究,得出了油池中润滑油污染度的变化规律,即从初始污染开始,按指数规律变化并最终趋向稳定平衡;润滑油污染变化程度随外界污染颗粒侵入率Ri和系统内部磨屑生成率Rp的增加而上升,随过滤比βu1,βu2,βu3的提高而降低,与润滑油的初始污染度C0无关等结论。     

河流相储层基准面旋回划分对比及沉积演化——以港西一区1断块为例

以地质、岩心和测井等资料的综合分析为基础,结合自然伽马曲线频率分析结果,对港西油田-区1断块新近系明二段(Nm2)油组河流相沉积进行基准面旋回划分与对比.Nm2油组可以划分为22个短期基准面旋回(对应于22个单层),根据基准面旋回叠加结构特征,可以将其合并为3个中期基准面旋回.对工区22个单层的沉积微相研究发现,Nm2...     

M3井井漏原因分析及录井监测预防方法

在多年录井实践及综合研究的基础上,以M 3井下技术套管后循环钻井液时发生的井漏为典型实例,系统分析研究了钻井液静液压力、正常钻进时环空压耗、套管外循环钻井液时环空压耗等求解公式和方法,求证出在套管外循环钻井液时,由于环空较小,较大的钻井液排量产生了较大的环空压耗,是导致井漏的主要原因。就如何借助综合录井实时采集参数多、智能化等优势,实时监控、预测地层压力、地层破裂压力,实时计算出不同钻井液排量下的环空压耗,实时预测发生井漏的最小钻井液排量等,提出相应解决思路。由此得出的结论表明,充分利用好工程录井技术,可减少井漏事故的发生。     

三片式LCOS激光投影显示中复合散斑的抑制

研究了三片式硅基液晶(LCOS)激光投影显示中散斑的成因、类型及其光学统计特性,并分析了激光散斑大小的测量方法。在此基础上,选用旋转散射片来减少三片式LCOS激光投影系统中产生的复合散斑,并通过一系列的仿真和实验,使得该激光投影机对比度C降到了人眼可接受的范围4.2%。证明了旋转散射片的方法能有效减少复合散斑,具有光学结构简单、实施性强等优点。     

Structure–Property Relationships in Natural Cellulosic Fibres. Part I: Characterisation

This is the first of a series of research papers featuring structure-property relationships in UK-grown natural cellulosic fibres, a renewable resource which may be extracted from the stems of plant fibres. They are composed of cellulose, hemicellulose, and lignin, together with other constituents, and, unlike seed hairs, have structures which make the plant stems strong and stiff. In the last few decades, fibres from agricultural crops have been replaced by synthetic fibres. In particular, this has resulted in under-utilisation of flax and hemp fibres, both of which may be grown in the UK. Although many studies have been carried out on bast fibres, and considerable information can be found in the literature, much of the information is of academic interest only, and the instances of verification through commercial use are rare. The driving force behind the current work was the EC strategy to improve self sufficiency in fibres, in order to reduce imports, and to find a substitute for jute and coir in industrial applications. The present study was mainly focused on flax fibres of different origins, particularly the straw waste product from linseed oil production. Until recently, this straw was burnt as a disposal route. The aim of the present investigation was to understand the effect of the chemical composition of different flax fibres on various physical properties, and, to compare them with those of other natural cellulosic fibres. It was concluded that seed flax, i.e. the fibre from straw left after harvesting linseed, has good potential for use in technical textiles.     

Study on Thermal Stress of Nylon 6/Copper Composite Powder in Selective Laser Sintering

3D finite element model of nylon 6/Cu composite powder is established for the selective laser sintering (SLS) process, and the factors of radiation, convection and thermal physical parameters highly nonlinear with temperature are taken into account. The load of moving heat source at different time and locations are carried out by the technique of element birth/death with ANSYS Parametric Design Language (APDL), and the dynamic distribution of thermal stress field in SLS is simulated with the method of indir...