ICP-AES法测定混合稀土金属中硅量

主要研究了采用ICP-AES法测量混合稀土金属中的硅含量.进行了分析谱线的选择,干扰实验.方法的检出限为0.022mg/l,回收率为95%～105%,RSD为1.83%～2.56%.方法准确、快速、简便.     

Ligament ruptures]

Ligamentous injuries of the knee are becoming commoner and commoner. They can involve the anterior cruciate ligament, the posterior cruciate ligament, or both ligaments together. The anterior cruciate ligament is the sportsman's injury. The diagnosis is a clinical one, with other diagnostic techniques only being used in the doubtful case. The treatment is well established, with surgery in the young and sportive patient, and a trial of non-operative treatment in the less active patient. The results of treatment are good. The posterior cruciate ligament is injured less commonly, and the diagnosis is sometimes missed. The injury is usually tolerated well, and the results of surgery are less reliable. For these reasons surgery is only performed in carefully selected patients.     

新疆巴里坤小加山东钨钼矿特征及成因分析

新疆巴里坤小加山东钨钼矿位于新疆东天山北部巴里坤县,是河南省地矿局第二地质勘查院2010年发现的小型钨钼矿,勘查程度达到详查。估算WO 3(332)+(333)金属量18317 t,矿床平均品位0.305%;Mo(332)+(333)金属量4346 t,矿床平均品位0.063%;该矿床的发现填补了东天山北部钨钼矿的空白,提高了对该区域矿产勘查工作的研究程度;矿床为一典型的钨钼共生矿,矿床类型为热液石英脉型矿床,矿体呈脉状产出;钨钼矿空间分布位置关系有明显的分带特征,矿床上部0~300 m以钨为主,下部300~700 m以钼为主;矿体主要赋存在泥盆系中统大南湖组下亚组(D 2 d b)火山碎屑岩(灰色凝灰岩)中,脆性断裂构造控矿,成矿母岩为华力西中期的斑状钠长花岗岩,为钨钼矿的形成提供了物质来源。     

基于矿相结构与冶金性能的酸性球团质量综合评价

针对中国高炉冶炼沿用的"高碱度烧结矿+酸性球团+块矿"的炉料结构,立足于化学成分、微观矿相结构、物理性能及冶金性能,从多角度对5种进口酸性球团矿的质量进行综合评价.结果表明,北美酸球物理性能相对较好,转鼓指数分别为95.67％、95.55％;巴西酸球还原后的抗压强度普遍偏低,分别为282.8、347.6 N.巴西酸球主...     

高频燃烧红外线吸收法测定锰矿石中碳和硫

建立了高频燃烧红外线吸收法测定锰矿石中的碳和硫含量的方法。仪器的最佳分析条件为吹扫时间10 s、延迟时间20 s、碳分析时间40 s、硫分析时间60 s。以Fe+W+Sn作混合助熔剂,按Fe+试料+W+Sn的加入顺序,试料熔融状态良好,试料中碳、硫释放完全。该方法与传统方法相比操作简便快速,方法的准确度和精密度试验的相对标准偏差在1.54%~4.75%之间,可替代传统方法使用。     

Steel Flow into a Mold from a Submerged Nozzle with Eccentric Outputs

The flow of steel melt into a mold has not been adequately studied. In general, analysis of the melt flow is a complex mathematical problem, and accordingly numerical modeling is employed. The present work employs Odinokov’s numerical method, which is based on a finite-difference form of the initial system of equations. This method has been successfully employed in continuum mechanics; in casting to determine the stress–strain state of shell-type molds; and in solving other technological problems. That suggests its universality. In the present work, it is applied to the hydrodynamic fluxes of liquid metal when steel is cast in a mold of rectangular cross section. The use of a submerged nozzle with eccentric holes for steel supply requires a three-dimensional mathematical model describing the metal fluxes into the mold. Odyssey software is used to simulate the processes in the mold. The calculation is based on the fundamental hydrodynamic equations and the proposed numerical model. The solution is obtained numerically and takes the form of a system of differential equations. The region of interest is divided into finite elements, and the system of equations is written in difference form for each element. The result obtained is the field of metal flow velocities into the mold. A numerical approach and a corresponding algorithm are developed for solution of the system of algebraic equations obtained and are incorporated in a computation program written in Fortran-4. By means of the mathematical model, the geometric dimensions of the mold and the cross section of the exit holes in the submerged nozzle may be varied. The model clarifies the pattern of metal flows, which affects the heat transfer by the mold walls, and permits determination of the optimal parameters of metal exit from the submerged nozzle in different casting conditions. As an example, the model is applied to steel casting in a mold of rectangular cross section (height 100 cm, horizontal dimensions 2000 × 40 cm). Steel flow from the submerged nozzle is eccentric in two directions within the horizontal plane. The results of solution are presented in graphic form. The pattern of metal fluxes into the mold is shown, and the magnitude and intensity of the fluxes is determined.     

黔西北垭都-蠎硐断裂带铅锌多金属矿研究现状及进展综述

黔西北垭都-蠎硐断裂带为中国西南大面积低温成矿域的一个重要单元。断裂带分布众多铅锌矿床(点),矿床类型独特,区别于MVT型、VMS型及SEDEX型。笔者通过分析研究区铅锌矿床地质构造特征及Pb、Sr、S、REE等同位素-稀土地球化学特征认为:铅锌等金属成矿物质来源于基底,硫元素来源于上覆赋矿地层。铅锌矿床的成矿时代集中于200Ma^225Ma,为晚印支期,即铅锌矿的形成为峨眉山玄武岩喷发-喷溢事件晚期或者之后的成矿事件。研究区铅锌矿的成矿系统:受地幔柱及构造作用的影响,起源于基底的流体不断萃取基底变质火山岩中的铅锌等金属元素形成含矿流体,含矿流体被构造导入沉积地层后进行大规模运移,运移至蒸发岩层于构造的破坏空间卸载形成铅锌矿床。     

转炉双渣操作炉渣中磷微区分布规律

对转炉双渣操作时的前期渣和终点渣中微观区域里磷的微观富集规律进行了研究,发现微区碱度Rm为2.0～2.5的微区中磷的富集程度最高;前期渣和终点渣中钙质量分数分别为16%～20%、33%～37%的微区中磷质量分数较高;微区磷富集与硅质量分数关系密切,终点渣微区中硅质量分数为9%～12%、前期渣微区中硅质量分数为13%～14%时,磷质量分数最高;微区铁质量分数对磷富集的影响明确,铁质量分数为5%～9%时磷质量分数最大;镁质量分数低的微区中磷质量分数较高。     

Review of Women and men: Interdisciplinary readings on gender.

Reviews the book, Women and men: Interdisciplinary readings on gender edited by Greta Hofmann Nemiroff (1987). This is a book of readings that could be used in either Women's Studies or Psychology classes that focus on sex roles. The book is divided into four major sections: 1) The epistemology of gender; 2) Life's conditions, stages, and choices; 3) Communication; and 4) Power. The second section is the largest and has five subsections (the early years, the body, fertility, relationships, and work). The articles are in general very well written and in addition to a bibliography most articles include a section listing suggested further readings. These suggestions should prove useful to students or teachers who wish to pursue a topic in more detail. The book has three major strengths. The first strength is the amount and centrality of Canadian content. The second strength is in the articles by and about men. The third strength is the presence of the section, The Epistemology of Gender. The weakness of the book is in what is not included. This is probably an inevitable problem with books of readings, as Nemiroff acknowledges in her introduction. In using the book as a text, the instructor should be aware of important topics and points of view that are omitted. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

焙烧天车双联夹具的机构改进

焙烧天车是电解铝制造行业的主要生产设备,双联夹具是焙烧天车的主要作业工具,主要完成炭块的运输工作。本文详细叙述了双联夹具机构的工作原理,较透彻分析了炭块在夹持过程中的受力状况。同时针对生产中出现问题,对夹具机构进行了改进,并取得了一定的效果。     

Patients with epilepsy who die suddenly have cardiac disease

This paper describes the design and fabrication of a soft liner-retained, implant-supported overdenture used in 10 patients over a period of 1 to 6 years. A final complete denture impression is made of the dental arch, including implant abutments extending 5 mm above the gingival tissue. The master cast is fabricated with actual abutments placed in the impression. After the final wax try-in, the denture is flasked in the usual manner with the metal abutments in place. Before packing with acrylic resin, plastic tubing 1 to 2 mm thick is placed around each abutment. The denture is trial packed and allowed to bench cure over night. The plastic tubing is then removed and a soft denture lining material is placed in these areas only. The flask is closed and cured according to the manufacturer's recommendation. The denture is delivered as a conventional overdenture.     

蒙乃尔多孔板的力学性能研究

多孔板是流化床布气元件的关键部件。工作中受流动气体和物料的作用,在多孔板上产生一定的压力、拉力和剪切力,因此要求多孔板具有优良的力学性能。采用粉末冶金法制备蒙乃尔多孔板,测定其不同部位的压缩和剪切性能。结果表明:多孔板边部压缩屈服强度可达143 MPa,弹性模量可达18.1 GPa;中心部位压缩屈服强度可达67 MPa,弹性模量可达8.2 GPa;弹性应变区间可达到3.0%;边部剪切强度可达153 MPa,中心为87 MPa。     

Melting Characteristics of Recycling Slag in Decarburization Converter and Its Application Effects

 The steel slag in the decarburization converter is treated by the little water-spreading (LWS) and the heat-stewed (HS) methods, which is used as the furnace burden of the dephosphorization converter. The slag characteristics by the LWS and the HS methods and its application effects as the furnace burden are researched. The results show the moisture content in the HS slag is higher than that of the LWS slag. There is higher total iron content in the HS and the LWS slags and almost same melting point. The dicalcium silicate content in the LWS slag is higher than that in the HS slag. The tricalcium silicate in the LWS slag is lower than that in the HS slag. There are a lot of calcium ferrite in the LWS and the HS slags, which is beneficial to dephosphorization and slag melting. The LWS and the HS slags are added to dephosphorization converter each charge by 3 or 6 t. The results show that the saving lime is 0. 7-1. 0 t for each charge. The petrographic constitute of final slag for the dephosphorization converter by adding the LWS and the HS slags is dicalcium silicate, RO phase and glass phase. There are a little calcium ferrite phase in the LWS slag, which is helpful to dephosphorization. So there are better dephosphorization effects for the LWS and HS slags.     

云南易门狮子山铜矿床围岩蚀变岩相与矿石组构特征研究

云南省易门狮子山铜矿床为昆阳裂谷典型的沉积-改造型铜矿床之一。矿床深部铜矿化与围岩蚀变有关,碳酸岩化与铜矿化关系密切。硅质白云岩类型铜矿体,矿石构造以脉状构造、浸染状构造为主;飘带矿矿石构造以层状构造为主。白云岩型铜矿中金属颗粒较细,为斑铜矿和黄铜矿;板岩型铜矿中金属颗粒较粗,为黄铜矿和黄铁矿。矿石化学成分具有高Si、Ca、Mg的特点,落雪组与鹅头厂组接触部位是重要的找矿地段。     

西藏洞中拉铅锌矿床地质特征及矿石、矿物研究

本文以西藏墨竹工卡洞中拉铅锌矿为研究对象,洞中拉铅锌矿床属于冈底斯成矿带中东段北部,矿区位于雅鲁藏布缝合带与班公湖-怒江缝合带间的冈底斯-念青唐古拉火山岩浆弧带,该带是青藏高原上白垩纪以来岩浆活动规模最大,活动期次最多,岩浆岩类型也最复杂的一个构造岩浆带。矿区构造主要为断裂和褶皱,矿区含矿地层为中二叠统洛巴堆组一段,矿体呈似层状-透镜状,矿区围岩蚀变强烈,硅化为矿区主要的的蚀变类型,与铅锌矿化有直接的关系,矿石矿物成分也很复杂,金属矿物以方铅矿、闪锌矿、黄铁矿、黄铜矿最多。     

Solution of niobium in iron during arc surfacing

The solution of niobium in iron during arc surfacing is simulated. The model is based on diffusional dissolution of niobium particles in metals. It includes diffusion equations, initial and boundary conditions, and also the equations of motion of the boundary between the media. The diffusion coefficient in liquid iron is assumed to much exceed that in the solid solution. The solution of the Stefan diffusional problem within the solid is found as a Fourier series in terms of cosines; the solution within the liquid is found in terms of error functions. The time for the dissolution of niobium is determined. It is 10–100 s for 10-μm particles at high temperatures.     

清洁无废回收利用尾矿集成化技术研究

研究了氰化提金尾矿的多元素回收利用技术和选铜尾矿浮选出的硫铁矿直接焙烧生成铁精粉等集成化技术。通过浮选试验和焙烧试验可以发现,在合适的工艺条件下,可以达到氰化尾矿中有价值多元素的综合回收,以及在工业中实现高品位硫铁矿直接焙烧生成合格铁精粉,最终可获得品位为Pb 30.29%、回收率为70.12%的铅精矿,品位为Zn 41.19%、回收率为74.93%的锌精矿,品位为Cu 7%的铜精矿和品位为S 40%~50%的硫铁矿;在最佳硫铁矿入炉品位、粒度、富氧程度下,可获得铁品位65%以上的铁精粉,为黄金工业向清洁无废化方向发展提供了新的途径。     

甘肃省礼县瓦屋沟金矿床地质特征及围岩蚀变

瓦屋沟金矿床是李岷金矿带上李坝金矿田内中型金矿床之一。矿区南测毗邻李坝金矿床,北侧与赵沟金矿床接壤。本文从区域地质背景、矿区地质概况、矿体特征以及围岩蚀变等对瓦屋沟金矿床进行了论述。矿带总体呈86°～115°方向延伸展布,受F3断裂构造控制。成矿特征显示:断裂构造是该区主要的控矿因素,围岩蚀变与矿化关系密切,矿化程度的高低与蚀变的强弱呈正相关,蚀变越强,矿化程度就越高;蚀变越弱,矿化程度就越低,与矿化关系最为密切的蚀变类型为黄铁绢英岩化,最不密切的蚀变类型为绿泥石化。     

Three-Dimensional Simulation on the Water Flow Field and Suspended Solids Concentration in the Rectangular Sedimentation Tank

A 3D computational fluid dynamics model for describing the water flow and suspended solids (SS) concentration distribution in a rectangular sedimentation tank is presented. The interfacial momentum transfer, buoyant forces, and the effect of sediment-induced density currents are considered. A convection-diffusion equation, which is extended to incorporate the sedimentation of activated sludge in the field of gravity, governed the mass transfer in the clarifier. The double-exponential law is used to describe the dependence of the settling velocity on the concentration. The results show that during the dynamic settling process of the sludge, the mud surface rose slowly, and a period of time later, the mud surface kept stability and reached dynamic equilibrium in the tank. The distribution of velocity along the z axis in the rectangular tank is not uniform, and the surface return flow is found. The turbulent kinetic energy is larger and dropped drastically in the inlet zone, while in the settling zone the turbulent kinetic energy is relatively small. Density current is formed, and the clear water zone, flocculation zone, lamella zone, and compression zone are found. Furthermore, under certain operational conditions, the influence of inlet baffle length on SS settling in the rectangular sedimentation tank is discussed. The prediction by the present model for liquid flow and SS concentration is confirmed by the experimental measurement in a rectangular sedimentation tank in Sweden reported by Larsen in 1977.     

Physical Simulation of New Desulphurization Technology Using Pulsed and Rotary Stirring-Injection

The contrast experiment of different stirring modes,which includes a new type of stirring-injection with the method of pulse and rotation,and the initial one-way stirring method,is done through physical simulation in the laboratory.The stirring methods of pulse and rotation are of two kinds.One is pulsed and rotary stirrer with positive and opposite directions.The other is pulsed and rotary stirrer with rotation-stop-rotation.The results show that the stirring mode of pulse and rotation has better effects than the one-way stirring method.The specific effects are that the mixing time of the melting bath is apparently shortened,the number of grains involved in the liquid surface is increased,and the residence time of air bubble in water is doubled.