布莱恩(Blaine)空气透过法测量粉末比表面

用自制Blaine空气透过法装置测量近球形羰基铁粉的比表面,所测得的平均粒径与Fisher平均粒径仪的测量结果及直接测量粉粒的统计平均粒径相近,但是大于氮低温吸附法的所测得结果。本装置简单,容易自制,使用方便。     

气体吸附法表征多孔材料的比表面积及孔结构

气体吸附法是测量多孔材料比表面积和孔结构的常用方法。本文介绍了气体吸附法的原理及实验过程,研究了氮气和氩气对同一材料比表面积测定结果的影响,结果表明当样品的比表面积大于1m2/g时,结果较一致;但当比表面积小于1m2/g时,采用氩气所得结果较为可靠。另外,分别用氩气和氮气对不同孔径的多孔材料进行了测定,结果表明气体吸附法测量孔径的适用范围为纳米级;通过和压汞法进行比较,发现在测大孔样品时,虽然孔径无法测定,但比表面积值是可信的。最后利用吸附脱附等温线对四种典型样品的孔结构进行了分析。     

用色谱法测定矿物比表面

比表面的测定是研究矿物表面性质的方法之一。测定的方法很多,应用较广泛的是对气体(或蒸汽)的吸附法。吸附法又可分为静态吸附法和动态吸附法。静态吸附法测量比表面虽然较为准确,但是它要求低温、高真空,设备和技术上受到相当大的限制;动态吸附法则是在常温常压、流动体系下,测量吸附剂对气体(或蒸汽)的吸附重量法,此法设备较简单,应用较广泛,但是它的测定时间较     

对Mn_3O_4比表面特性的研究

对不同工艺条件下的Ｍｎ３Ｏ４粉末进行静态低温氮吸附测试。利用ＢＥＴ理论计算其比表面。结果表明，氮吸附法比表面较好地反映了Ｍｎ３Ｏ４的比表面特性。     

用分子筛吸附法代替碱洗法净化贫氪氙气中水份和二氧化碳

本文介绍了稀有气体贫氪氙气中水份和二氧化碳净化设备中采用分子筛吸附工艺取代碱洗法取得了良好效益。     

粉末压片X射线荧光光谱法测定三氧化二钒中主次成分

采用粉末压片X射线荧光光谱法测定三氧化二钒中钒、磷、铁、氧化钾、氧化钠、硫含量,通过选择合适的制样条件、确定仪器最佳参数,选用不同生产线生产的具有含量梯度的样品,通过化学定值后绘制校准曲线.以仪器提供的基体校正方法消除吸收与增强效应。本法测量准确度、精密度较好,所得结果与湿法化学分析结果一致。     

粉末压片-X射线荧光光谱法测定混匀矿中TFe含量及其应用

以粉末压片制样，研究确定制样条件，选择仪器最佳参数，并绘制标准工作曲线，建立X射线荧光光谱法测定混匀矿中TFe含量的检测方法（TFe的测定范围为52.0%～67.0%）。将本方法的测定结果与化学分析方法相比较，实际使用结果表明，用该方法测定混匀矿中全铁含量，测量准确度、精密度较好，所得分析结果与化学分析结果一致，能满足生产检验要求。     

X射线小角散射法测量纳米粉末的粒度分布

在常规高分辨X射线衍射仪上应用小角散射法测量了ZnO、ZrO2、Fe和Al2O3纳米粉末的粒度分布。测量结果与专用X射线小角散射仪器的测量结果一致，并经TEM分析验证。证明在常规高分辨X射线衍射仪上应用小角散射法测量纳米粉末的粒度是可行的。与采用四狭缝系统或Kratky狭缝系统的专用小角散射仪相比，该方法的特点是操作简单，成本较低，易于推广。目前此法可测量1～300nm范围的粉末粒度。     

粗氪氙塔蒸发器堵塞的原因分析及处理

在装置运行过程中发现粗氪氙塔蒸发器贫氪氙气侧前后压差逐渐扩大,判断为蒸发器堵塞。结合运行记录,分析排查堵塞原因,确认是由于分子筛再生气中含水,在冷吹阶段后期少量水分存在分子筛内,当进入吸附周期时,水分随贫氪氙气进入塔内所致。通过系统大加温、分子筛活化等措施,严格监控加温时各管路露点,确保了装置正常运行。     

S400G中硫含量检测的不确定度评定

测量不确定度是反映被测量值的分散性、与测量结果相联系的参数,是对测量结果质量的定量表征。结合宝钢特钢检测中心炼钢炉前分析作业区的生产实际,依照国标GB/T 20123—2006,运用高频燃烧红外吸收法对S400G中硫含量进行分析,对样品的测量重复性分量、校正时测量变动性分量进行了A类不确定度评定,对标准物质硫含量分量、称量引起的分量、仪器显示分辨率的分量分别进行了B类不确定度评定,明确了评定过程所需参数的数据采集和计算方法。结果表明,采用高频燃烧红外吸收法的检测可信度较高,同时也为其他钢种的高硫含量测量评定提供了参考依据。     

石灰微观结构对铁水预处理脱硫的影响

采用比表面积1.891~2.664 m²/g和平均孔径575.5~814.9 nm四种不同结构的活性石灰在高真空电弧熔炼旋淬一体机中进行铁水预处理脱硫实验。用扫描电子显微镜分析不同石灰样品表面形貌,并用全自动压汞仪测量石灰的比表面积和平均孔径。实验结果表明铁水脱硫率随着石灰平均孔径的增大而减小,随着比表面积增大而提高;最佳脱硫剂配比为1:50。可将铁水中硫含量从0.014%脱至0.001%。     

阳极氧化法测定烧结多孔体表面积

在烧结动力学的研究中,通常要测定烧结体的表面积。本文提出了用阳极氧化法测定阀金属烧结多孔体的表面积。经比较各种计算方法,认为采用氧当量法可得到较好的结果。     

原料粉末对制备碳化钒的影响

为工业化生产提供实验室研究基础,本文以V2O5和纳米碳黑为原料,利用碳热还原法,在常压下碳管炉中得到了V8C7粉末。通过X射线衍射仪(XRD)、扫描电镜(SEM),分析了原料对反应进程的影响。结果表明:采用普通球磨干混的方式时,比表面积(BET)为112m2/g的碳黑可以加速反应进程,过低或过高都不利于反应的进行;细粒径的V2O5原始粉末可明显加快反应进程,最终得到大小均匀,粒度1μm以下的球形碳化钒粉末。反应机理研究表明,固-固反应的速率与反应组元的颗粒大小和混合均匀程度,以及不同反应组元之间的接触面积有很大关系。     

攀钢板坯连铸机二冷喷嘴热态特性的测定

利用热传系数测试装置，系统地对攀钢板坯连铸机上使用的喷嘴进行了热态性能的测定，获得了这些喷嘴在不同水量和气量下传热系数随铸坯表面温度的变化关系。测试结果为喷嘴的选择以及进一步研究二冷传热机理和设计合理的二冷工艺制度打下了基础。     

THE POWDER METALLURGY OF RUTHENIUM

Abstract

An investigation of the powder metallurgy of ruthenium is described, from the reduction of ammonium ruthenium chloride to the working of sintered compacts. The powder properties measured were specific surface area, by a simplified BET method, and tap density. The dependence of these properties on the conditions of reduction has been determined. The surface area of powders varies from 1 to 10 m²/g in the temperature-of-reduction range 700-350°C. The tap density is also variable (1–3 g/c.c.) and is generally related to the surface area. The effects of compacting pressure and temperature on sintering are described, the progress of sintering being observed by measurements of the “open” and “closed” porosity present in samples. Compact densities up to 95% of theoretical can be obtained by sintering at 1500°C. The selection of powder properties and compacting pressures to be used in the production, by vacuum sintering at 1500°C, of high-density compacts for working, is governed by the necessity to maintain open porosity during the heating cycle up to at least 1200°C, as considerable gas evolution occurs at this temperature; at the same time it is essential that good densification shall have occurred even at this stage. These conditions can be met by using powder with a surface area of 2–5 m²/g and compacting pressures in the range 0·5–25 tons/in ².

Observations on the hot working of sintered compacts indicate that ease of working is related to the surface area of the powder.     

Study of the behavior of biological molecules in a thin gap by refractive index and force measurements with an automatic surface force apparatus

The automation of the mica surface displacement of a surface force apparatus (SFA) increases the accuracy of the intermolecular force measurements that is obtained without the presence of the experimenter. The automatic device cancels any thermal drift and the stability of the mica surfaces is optimum. The distance between the mica surfaces is measured by Tolansky multiple-beam interferometry (FECO method) which offers a sensitivity of 0.1 nm in the direction perpendicular to the plane of contact area. The mean refractive index of the medium between the mica plates is computed from simultaneous measurements of the wavelengths of two successive fringes of equal chromatic order (FECO). A conversion of an isotropic molecule to another anisotropic molecule can be identified from the variations of the refractive index. In good conditions, we can compute the local concentration of the molecules in the gap of the device, and estimate the Young's modulus of a protein.     

Solid-state NMR studies of 1H spin diffusion in adsorbed organic molecules

1H spin diffusion times of toluene (MB) and tetrahydrofuran (THF) adsorbed on a series of porous solids (charcoal, SiO2 and Al2O3) were measured by a selective inversion technique. The experimental results show that they cover a wide range (from less than one millisecond to several hundreds of milliseconds). For all samples, a tri-exponential behavior was observed in the magnetization recovery processes of the negative peaks. This is attributed to the existence of the two different kinds of spin diffusion processes in addition to the T1 relaxation. One is assigned to the intermolecular spin diffusion between the surface acidic protons of the adsorbent and the organic molecules adsorbed on the solid surface, the other to the intramolecular spin diffusion of adsorbed molecules. Due to hydrogen bonding between the surface hydroxyl groups and the adsorbate, the intermolecular spin diffusion of THF adsorbed on various solids is more effective compared to that of adsorbed MB. In addition, the intermolecular 1H spin diffusion between charcoal and adsorbed THF molecules was confirmed by indirect measurement suggested by Tekely et al.     

纳米二氧化硅粉体的微乳液制备及表征

以硅酸盐溶液／环已烷／聚乙二醇辛基苯基醚／正戊醇体系的微乳液反应为基础,以浓硫酸为 沉淀剂,采用微乳液法制备了高比表面积纳米SiO2粉体,并通过比表面积(BET),透射电镜 (TEM),红外光谱分析(IR),X射线衍射(XRD),差热一热重分析(DTA-TG)对样品进行了形态表 征和物相分析。研究结果表明:采用微乳液法制备的纳米SiO2粉末均由非晶态物质组成,粉体颗 粒形貌近似呈球形,粒径为15-35nm,比表面积达580-630 m2／g。