材料期刊网

MOTIONS OF ALLOYING ADDITIONS IN GAS STIRRED LADLES

S.C. Fan , B.K. Li , J.C. He

金属学报(英文版)

A mathematical model has been developed to analyze the flow patterns and subsurface trajectories of spherical shaped particles (alloy additions) in gas stirring ladles. First,a numerical method to solve fluid flow problems in conjunction with a curvilinear coordinate system is proposed. The internal boundary in flow field, which must be designated in the cylindrical polar coordinate system, can be avoided by using bodyfitted coordinate system (BFC). Consequently, computed flow of molten steel and paths of alloying additions are able to cross smoothly the geometric centerline of cylindrical vessel. Second, motion of particles is calculated in the three-dimensional coordinate system, the modification of parameters, such as the drag coefficient and density in the gas plume region, is examined. When the density of sphere is closer and closer to that of fluid, the path of motion is longer and longer. If the plug is moved off-centered to the half of radius, the path of sphere is prolonged, and the sphere may go through the geometric centerline of vessel, reach the deeper region. The immersed depths increase with increasing entry velocities.

关键词: alloying addition , null , null

Ba在C2S-C3S矿物相中固溶机理探讨

陈树东 , 项建明 , 王晓翠 , 洪笑

硅酸盐通报

以Ca(OH)2、SiO2、Fe2O3、Al2O3化学纯为原料,分别掺入不同质量分数的Ba(OH)2制备不同矿物相组成的熟料相,运用化学分析、XRD、SEM、水化热测试方法,研究掺Ba(OH)2后熟料相中硅酸三钙-硅酸二钙(C3S-C2S)混合相组成、晶型、新相生成的变化规律.结果表明:Ba(OH)2一定程度上削弱C3S形成,且稳定β-C2S形成效应明显,矿物相体系中α'-C2S、α-C2S量减少并转换为β-C2S,掺量大于2.5％后有新相Ba0.48 Ca1.52SiO4形成;Ba(OH)2掺入促使矿物相中C2S相明显增多,晶粒整体尺寸变小,边界变圆润;随Ba(OH)2掺量递增,熟料样的水化速率呈持续减小的趋势变化.

关键词: C3S相 , β-C2S , 水化速率 , 水化

P2O5对C6A4MS-C2S-C4AF系中β-C2S稳定作用研究

马德伟 , 杨利群 , 徐先宇

材料科学与工程学报 doi:10.3969/j.issn.1673-2812.2001.02.020

本文研究了C6A4MS-C2S-C4AF系中R2O5对β-C2S的稳定性问题.结果表明:P2O5的掺入能有效抑制β-C2S转变为γ-C2S,稳定β-C2S;少量P2O5对C6A4MS的形成无抑制作用.

关键词: P2O5 , C6A4MS-C2S-C4AF系统 , β-C2S稳定

The crossover from parallel shift to fan-shape broadening of the superconducting transition of La(1.44)Nd(0.4)Sr(0.16)CuO(4) films in magnetic fields

Superconductor Science & Technology

In this paper we report the transport properties of c-axis-oriented superconducting La(1.44)Nd(0.4)Sr(0.16)CuO(4) films on LaSrAlO(4) substrates with different thicknesses in various magnetic fields parallel and perpendicular to the c axis of the films. It is found that with decreasing film thickness there is a crossover from the parallel shift to fan-shape broadening in the resistive transitions. Moreover, for both field configurations, the flux pinning potential U(0)(H) of the film shifts upward with an order of magnitude with increasing in-plane compressive strain. These results indicate that the compressive epitaxial strain and strain-induced destabilization of the static charge stripes are important aspects for the promotion of superconducting transition temperature as well as the flux pinning potential.

关键词: high-temperature superconductors;crystal thin-films;flux motion;la2-xsrxcuo4;strain;insulator;dependence;behavior

C-S-H 凝胶及其研究方法

杨南如

硅酸盐通报 doi:10.3969/j.issn.1001-1625.2003.02.011

在分析C-S-H凝胶的复杂性和特征的基础上,就测定它的化学组成、C-S-H凝胶中[SiO4]4-四面体的聚合度及其结构的化学和物理的方法作了简要介绍.现代各种测试方法的出现和使用,对C-S-H凝胶的组成和集中[SiO4]4-四面体的聚合结构有了较为完整的概念.

关键词: C-S-H凝胶 , 化学组成 , 凝胶结构 , 测定方法

Q相-C2S-C4AF-C12A7系列水泥形成的研究

姜奉华 , 徐德龙

硅酸盐通报 doi:10.3969/j.issn.1001-1625.2004.06.006

通过研究Q相与C2S和Q相与C4AF的共存条件,构造Q相-C2S-C4AF水泥系统,对此系统水泥形成条件进行研究.研究表明:Q相与C2S和Q相与C4AF能够共存,可以组成Q相-C2S-C4AF-C12A7水泥系统.在Q相-C2S-C4AF-C12A7水泥系统中,Q相在1270℃开始生成,随着温度的升高,Q相的生成量逐渐增大;采用V2O5对β-C2S具有较好的稳定作用.随着C4AF量的增加,Q相的量也在增加,同时,烧成温度降低.

关键词: Q相 , Q相-C2S-C4AF水泥 , 形成条件 , 抗压强度

C2S前导物对C3S形成及活化能的影响

管宗甫

硅酸盐通报

用工业原料在不同温度预合成C2S(2CaOSiO2)为主要矿物的前导物,并以该前导物为基础,补入适量的钙,在不同温度下二次烧成水泥熟料.结果显示:采用1250℃、1300℃和1350℃预合成的C2S前导物配料二次烧方法,有利于熟料在低温下烧成,在1350℃左右实验熟料样品中游离氧化钙即可小于1.0％.相应C3S在熟料体系中的表观形成活化能相比不同配料烧成的对比组明显降低,而不同温度制备的前导物配料,C3S在熟料体系中的形成活化能相差无几.

关键词: C2S前导物 , 二次烧成 , 水泥熟料 , 硅酸三钙 , 活化能

Molecular Electrical Conductor Ni(C_3S_5)_2

Hong LEI (Dept. of Electronic Engineering , Shandong University , Jinan 250100 , China)Qi FANG and Minhua JIANG (Institute of Crystal Materials , Shandong University , Jinan 250100 , China)Yueming SUN (Dept. of Chemistry Southeast University Nanjing 210093 , Chi

材料科学技术（英文）

The molecular based electrical conductor Ni(C3S5)2 has been prepared and its conductivity has been measured from room temperature down to 60 K. Above 167 K Ni(C3S5)2 exhibits a semiconductive behaviour, below this temperature it turns to exhibit metallic conductivity. Based on a tight-binding energy band calculation, an expression for the number of conducting electrons has been deduced. The calculated conducting activation energy is quite well in accordance with the measuring value.

关键词:

Q相-C2S系统中V2O5对β-C2S稳定性的研究

杨利群 , 祝名伟 , 封汉昌 , 徐先宇

材料科学与工程学报 doi:10.3969/j.issn.1673-2812.2000.03.016

本文研究了Q相-C2S配合料中V2O5对β-C2S的稳定性问题.结果表明,微量V2O5可以稳定β-C2S,使Q相与β-C2S可在常温下共存;Q相-C2S配合料中V2O5/C2S在0.8～1.0%的范围内V2O5稳定β-C2S的效果最好.

关键词: Q相 , C2S , V2O5 , CaO-MgO-Al2O3-SiO2系统

Q相-C2S-C4AF-C12A7水泥作为膨胀剂的研究

姜奉华 , 徐德龙

硅酸盐通报 doi:10.3969/j.issn.1001-1625.2005.04.026

采用普通硅酸盐水泥作为基体、Q相-C2S-C4AF-C12A7水泥作为膨胀剂、加入少量石膏的条件下进行试验研究.研究表明:Q相-C2S-C4AF-C12A7水泥能够作为膨胀组分,调节Q相-C2S-C4AF-C12A7水泥和SO3的量,能够得到所要求的膨胀水泥.从DTA和XRD得知,其膨胀源主要是钙矾石(AFt),它形成的速度及数量,可以通过控制Q相-C2S-C4AF-C12A7水泥和SO3的量来实现.

关键词: 膨胀水泥 , 膨胀剂 , 微观分析 , 钙矾石