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961.
为了研究钇对E36船板钢中夹杂物成分和形貌的影响,对钇处理后E36船板钢中典型夹杂物进行热力学计算,并通过扫描电镜及能谱仪对钇处理前后E36船板钢中夹杂物进行检测分析,观察典型夹杂物形态和尺寸。结果表明,未添加稀土钇的E36船板钢主要为长条状MnS夹杂物;添加稀土钇后,钢中夹杂物主要为球状或类球状的含钇复合夹杂物。当钢中钇质量分数为0.007 8%时,夹杂物主要为球状或类球状的Y2O2S夹杂物和Y2O3夹杂物;当钢中钇质量分数增加至0.037 7%时,夹杂物改性为球状或类球状Y2O2S夹杂物、YS夹杂物和Y2O3夹杂物。 相似文献
962.
963.
Inclusion of guests inside molecular capsules may have pronounced effects on their chemical reactivity. This article provides a quick summary of research on the electrochemical reactivity of encapsulated redox-active guests. A brief account of the results obtained with simple hosts, such as cyclodextrins and cucurbiturils, starts the article. However, these hosts can only provide partial encapsulation. Most of the article is devoted to the results obtained by the authors’ group on the inclusion of ferrocene, cobaltocenium, and tetrathiafulvalene in molecular capsules formed by cavitand-type ligands, which give rise to supramolecular assemblies that provide full encapsulation. In general terms, trapping of redox-active centers inside molecular capsules leads to a substantial attenuation of their electrochemical kinetics, which results in electrochemically silent properties in extreme cases. However, the magnitude of this kinetic attenuation cannot be rationalized by simple criteria based on the overall size of the supramolecular assembly. 相似文献
964.
选择3种冶金因素有代表性的碳钢及低合金钢, 通过极化实验方法确定点蚀诱发初期及点蚀期的电位值, 利用显微腐蚀实验方法和电子探针分析了不同夹杂物在诱发点蚀过程中的特征, 并在利用琼脂涂封的条件下, 考察及分析了点蚀诱发时夹杂物溶解析出情况。结果表明:夹杂物是钢中主要点蚀诱发源, 钢基体与夹杂物交界处的钝化膜保护作用最弱, 点蚀均从该处诱发;点蚀诱发初期, 钢基体与夹杂物交界处的钝化膜破裂时, 对硫化物夹杂, 优先析出的是铁离子, 而不是硫离子;夹杂物的成分及形态的不同都会影响到产物的溢出位置。 相似文献
965.
A study is reported of a commercial print-bonded non-woven fabric (Keybak), made of viscose staple fibres arranged to contain a pattern of elliptical holes and print-bonded by acrylic latex in strips. An analytical model based on the structural features and using a composite-materials approach was employed to interpret the experimental measurements of the bending stiffness of the fabric. The grouping of the fibres in the fabric into straight and severely curved ones permits freedom of relative fibre motion among curved fibres and requires only the straight fibres to resist the bending moment. 相似文献
966.
967.
968.
The mechanism of inclusion aggregation in liquid steel in swirling flow tundish is analyzed by applying the theory of flocculation which was developed in the field of colloid engineering. The gas bridge forces due to the micro bubbles on hydrophobic inclusion surfaces were considered responsible for the inclusion collision and agglomeration, which can avoid the aggregation to breakup. The quantity of micro bubbles on hydrophobic inclusion particle is more than that on hydrophilic one. The trend of forming gas bridges between micro bubbles on particles is strong in the course of collision. The liquid film on hydrophobic particles is easy to break during collision process. Hydrophobic particles are liable to aggregate in collision. According to the analysis of forces on a non-metallic inclusion particle in swirling chamber, the chance of inclusion collision and aggregation can be improved by the centripetal force. Hydrophobic particles in water are liable to aggregate in collision. Hydrophilic particles in water are dispersed although collision happens. The wettabiliy can be changed by changing solid-liquid interface tension. The non-metallic inclusion removal in swirling flow tundish is studied. It shows that, under certain turbulent conditions, the particle concentration and the wettability between particles and liquid steel are the main factors to induce collision and aggregation. 相似文献
969.
检查北满特钢生产的35MnBM钢发现凹陷和裂纹。采用金相观察、扫描电镜观察和能谱分析等方法对35MnBM钢裂纹形成的原因进行了分析。提出措施:严格控制夹杂物含量、尺寸和分布,控制表面凹陷脱方现象,以消除裂纹形成的内在、外在原因。 相似文献
970.
We describe the molecular recognition of polymeric attached isomers meta‐isopropylphenol and para‐isopropylphenol, respectively, in a copolymer of N‐isopropylacrylamide (NIPAAm) by use of randomly methylated β‐cyclodextrin (RAMEB‐CD). The acrylic monomers 4‐ and 3‐isopropylphenylacrylate were synthesized and radically copolymerized with NIPAAm yielding the corresponding polymers. The supramolecular structures resulting from complexation with RAMEB‐CD were characterized using dynamic light scattering, turbidity, NMR spectroscopy and isothermal titration. We found differences in binding constant, mean coil size and cloud point as a result of different complexations of the mentioned polymer‐bound isomers with RAMEB‐CD. Copyright © 2012 Society of Chemical Industry 相似文献