Importance of Modeling in Estimation of Properties of Refining Slags

Structures and various properties of refining slags can be estimated by the use of classical molecular dynamics simulation. The appropriateness of the estimation depends on the interatomic potentials used in the simulation. If modeling of the interatomic potentials is sound, the parameter values in the potential functions become equivalent to physical property values and their evaluation based on fitting of calculated properties with the measured values becomes equivalent to the measurement of the “physical properties”. This situation is also applicable to thermodynamic modeling. Once the parameter values, i.e. the “physical properties”, are evaluated by the use of some measurements or ab initio calculations, the simulation by the use of the model and the model itself have the ability of estimating a wide range of properties of refining slags. In this scope, a molecular dynamics approach of molten CaO‐SiO₂, an evaluation method of energy parameter values in the Cell Model as a slag thermodynamic model by the use of NMR measurements are discussed. Estimation of viscosity and relative molar volume of slags by the use of thermodynamic properties is also mentioned.     

Adhesive luting cements--classes, criteria, and usage

Clinical studies have shown that recurrent decay and lack of retention are the major causes of traditional crown and bridge failure. Optimal marginal accuracy and preparation retention form are important pre-requisites for longevity, as well as good patient oral hygiene. In an effort to provide improved clinical success, new classes of luting agents with improved physical properties and new therapeutic capabilities have been developed. Conventional glass ionomer cements provide fluoride release and adhesive properties. Recently introduced resin-modified glass ionomer luting materials add the potential for increased resistance to dissolution and improved physical and biological attributes. The resin luting cements are more difficult to use but provide greatly increased bonding capabilities and are necessary for strength requirements of all-ceramic restorations. This article describes the three classes of adhesive luting materials, provides a comparison of biological and physical properties, describes the indications and limitations of each class, and makes recommendations for clinical usage.     

纳米粉末制备方法综述

纳米粉末具有特殊性质 ,并在各个领域得到广泛应用。本文详细介绍了制备纳米粉末的方法 ,如机械法、物理法和化学法。并对各种方法的优缺点进行了介绍。指出了纳米粉末制备方法的未来发展方向     

Elastic moduli and tensile and physical properties of heat-treated and quenched powder metallurgical Ti-6Al-4V alloy

Elastic moduli and tensile and physical properties were measured at room temperature on texture-free powder metallurgical (PM) Ti-6Al-4V alloy as a function of heat treatment and quenching (HTQ) from temperatures between 600 °C and 1200 °C. The elastic moduli and other physical properties, which are often regarded to be constant, were found to depend strongly on heat treatment. The property variations are interpreted on the basis of the phases and phase volume fractions which are controlled by HTQ. For example, soft metastable (beta/alpha′) phase formed by 800 °C HTQ induces the lowest values of yield strength and Young’s modulus. Alpha + beta microstructures are associated with a low Poisson’s ratio of 0.27, while alpha′ microstructures have a high Poisson’s ratio between 0.35 and 0.36. Several other mechanical and physical properties are derived from the measured properties. Formerly Research Associate, Institute for Materials Research, German Aerospace Research Establishment An erratum to this article is available at .     

合理利用我国高钼钨精矿

面对我国许多矿山选矿产出的高钼钨精矿(或次精矿)越来越多的状况,根据不同原料及不同用户需要,提出了合理利用我国高钼钨矿资源的几条途径。     

Physical properties of mould powders for slab casting

Abstract

The application of mould powder for certain steel grades is mainly based on experience. In an ECSC project, an inventory was made addressing the physical properties that are the basis of this experience. It is concluded that, for each steel grade, common physical properties (e.g. viscosity, melting temperature) can be identified. There is, however, a large variation in the values of physical properties used. It is therefore not possible to find any relationship between slag properties and casting conditions, given the steel grade to be cast. Wider ranges in physical properties are possible and realistic to enable casting of a steel type at a particular speed.     

东部盆地群下白垩统储层物性特征与影响因素

东北地区东部盆地群下白垩统发育常规储层和非常规致密储层两种类型的储层,为了研究这两种储层的分布特征、指导勘探部署,在搜集相关资料的基础上,完成了一些新的测试,研究了下白垩统储层的物性特征及其影响因素。结果表明:东部盆地群只有汤原断陷、方正断陷、宁安盆地、延吉盆地、珲春盆地、蛟河盆地和松江盆地的下白垩统储层属于常规储层,其余盆地的下白垩统为超—特低孔超低渗致密储层;储层物性主要受沉积相、成岩作用和构造抬升剥蚀的影响。从原型盆地的边缘到沉积中心,水动力减弱,粒度变细,储层厚度减小,物性变差。随储层成岩作用的增强,储层物性变差。研究区南部浅层的致密储层是由于3250 m左右的抬升剥蚀和火山喷发过程中的高温烘烤作用所造成的。     

Metallurgy,Microstructure and Properties of a New Nitride Strengthened Nickel‐Chromium Superalloy

The nitrogen content of Ni‐base superalloys for high temperature service is generally kept below about 0.05 wt.‐% to avoid detrimental precipitation of nitrides. These nitrides are said to have a harmful influence on mechanical properties and workability of these alloys. However, some recent studies and research conducted with nitrogen strengthening of Ni‐Cr‐alloys have resulted in an alloy with excellent physical and mechanical properties. The applied PESR (Pressurized Electro‐Slag Remelting)‐Technology provided up to 1.0 wt‐% nitrogen in a NiCr7030‐alloy.The homogeneously distributed nitrides prevent the alloy from excessive grain growth thus providing stable mechanical properties, i.e. impact toughness even after long term exposure. The new alloy easily exceeds R_m= 850 MPa at room temperature and 600 MPa at 600 °C as relevant design values. This paper introduces this new alloy with its very special metallurgy, microstructure, and its physical and mechanical properties.     

Correction

Elastic moduli and tensile and physical properties were measured at room temperature on texture-free powder metallurgical (PM) Ti-6Al-4V alloy as a function of heat treatment and quenching (HTQ) from temperatures between 600 °C and 1200 °C. The elastic moduli and other physical properties, which are often regarded to be constant, were found to depend strongly on heat treatment. The property variations are interpreted on the basis of the phases and phase volume fractions which are controlled by HTQ. For example, soft metastable (beta/alpha′) phase formed by 800 °C HTQ induces the lowest values of yield strength and Young’s modulus. Alpha + beta microstructures are associated with a low Poisson’s ratio of 0.27, while alpha′ microstructures have a high Poisson’s ratio between 0.35 and 0.36. Several other mechanical and physical properties are derived from the measured properties. Formerly Research Associate, Institute for Materials Research, German Aerospace Research Establishment The online version of the original article can be found at     

Numerical Simulation of Dendrite Evolution during Solidification Process

Solidificationisaverycomplicatedprocessinclud ingheatandsolutetransfer ,phasetransitionandinter facemigrationprocesseswhichdirectlyinfluencesolidi ficationmicrostructure .Solidificationmicrostructureisanimportantindextoevaluatemechanicalandotherphysicalpr…     

Properties of bulk metallic glasses

A relatively small number of revolutionary materials have been discovered in the field of physical metallurgy and metal physics in the last several decades, and bulk metallic glasses are among them. Their strength and hardness are considerably higher and their modulus of normal elasticity is considerably lower than that of crystalline alloys, which leads to large stored elastic strain energy. These materials also have very good corrosion resistance. In this article, we present the properties of bulk metallic glasses, in particular, thermal, mechanical, magnetic, and electrical properties, corrosion resistance, as well as the application fields of these alloys.     

Further Tests of Beam-to-Column Connections for Pultruded Frames: Flange-Cleated

Four full-sized physical tests have been conducted to determine the behavior of semirigid beam-to-column connections for frames of pultruded profiles. The tests were on 203 mm (8 in.) sized joints with connection details specifically chosen to provide moment resistant connections, thereby making it an option to include their semirigid action in frame design. Full details on the preparation of specimens and the physical test results are presented. Experimental moment-rotation curves have been obtained under short-term loading and modes of failure established. The suitability of the four connections to provide acceptable semirigid properties is assessed and future work recommended.     

Development of in vitro performance tests and evaluation of nonabsorbable monofilament sutures for cardiovascular surgery

There have been reports suggesting that polypropylene (PP) monofilament sutures are associated with mechanical failure. To overcome this problem, a new monofilament suture made from polyvinylidene fluoride, under the trade name of Teflene, has been developed. Few studies have measured the in vitro properties of Teflene sutures, and those that have, have been limited to a few tensile properties of the straight suture such as tensile strength, elongation, and creep behavior. The in vitro performance properties of Teflene sutures were evaluated and compared with those of commercial sutures made from PP such as Prolene and Surgilene in four sizes, 2-0, 3-0, 4-0, and 5-0. The performance properties of sutures included both the physical properties of straight sutures, such as suture diameter, tensile strength, elongation, surface roughness, coefficient of friction, bending stiffness, and tissue drag, and the knot characteristics, such as knot pull strength, knot run-down, and knot security. Existing standard test methods and testing instruments were used if available to measure certain suture properties such as diameter, tensile strength, knot pull strength, and some physical properties. The other novel test methods and unique accessory devices needed to perform the tests for measuring tissue drag, knot run-down, coefficient of friction, and knot security were developed in the authors' laboratories, and the comparative results are reported for the first time. From the test results, Teflene sutures were found in general to possess equivalent characteristics to those of existing PP commercial sutures, but some differences also were observed, such as greater elongation and less knot run-down. These differences may give them a unique feel and handling performance, especially in terms of making a knot, sliding it into position, and causing less damage to adjacent tissue.     

纳米碳管在现代汽车工业上的应用

纳米碳管具有独特的结构和优异的物理与力学性能,在现代工业中拥有广阔的应用前景,在汽车上的应用也倍受关注。据此,对纳米碳管在汽车上已有的应用及潜在的应用进行了综述,包括汽车新能源动力系统、轻量化结构材料、多功能复合材料等,希望能够给汽车新技术的开发和新材料的利用提供参考。     

Pragmatic assessment of physical activity

Nurse practitioners are confronted with the need to measure the physical activity levels of clients. There is no "gold standard" for measurement in the field. Nurses increasingly use physical activity for assessment, intervention, and evaluation. Selection of the appropriate tool depends on the purpose of the assessment, the client population, practicality, and psychometric properties of the instrument. Nine physical activity instruments with good psychometric properties, economy, and acceptability are presented to assist with instrument selection.     

Mammary gland expression of transgenes and the potential for altering the properties of milk

Transgenic animals are a useful in vivo experimental model for assessing the ability and impact of foreign gene expression in a biological system. Transgenic mice are most commonly used, while transgenic sheep, goats, pigs and cows have also been developed for specific, "applied" purposes. Most of the work directed at targeting expression of transgenes to the mammary gland of an animal, by using a milk gene promoter, has been with the intent of either studying promoter function or recovering the desired protein from the milk. Transgenic technology can also be used to alter the functional and physical properties of milk resulting in novel manufacturing properties. The properties of milk have been altered by adding a new protein with the aim of improving the milk, not of recovering the protein for other uses.     

白云鄂博西矿矿岩物理特性及可钻性试验研究

文章以包钢白云鄂博西矿区范围内的主要矿岩为研究对象,对不同岩种进行了取样,并做了物理性能和工程力学性质试验,同时对矿岩的可钻性进行了实验室测试和现场测试,对数据进行了相关性分析,发现矿岩物理性能和工程力学性质与可钻性之间存在较强的相关性,从而预测矿岩的可钻性。     

铂族金属在现代工业中的应用

铂族金属是一类用途广泛的贵金属,通过其不同的物理化学性能分别描述了其在汽车、电子、医药、石油化工、燃料电池等工业领域的应用及发展状况.     

邯邢铁矿粉烧结试验研究

研究了邯邢铁矿粉的理化性能和烧结性能,提出了该矿粉生产高碱度烧结矿和合适配比与技术操作参数,解决了生产高碱度烧结矿粉化的问题。     

碳化硅颗粒增强铝基复合材料的热性能研究

碳化硅颗粒增强铝基复合材料由于具有优异的机械性能和物理性能得到越来越广泛的应用，特别是热物理性能能够满足电子封装领域越来越高的要求，适应电子器件集成化程度不断提高的发展趋势。本文介绍和分析影响其导热性能、热膨胀系数及热稳定性的主要因素。