摘要： An exploding wire system has been used to examine the effects of microstructure on the dynamic fracture behavior of high purity iron, 0.2% C steel and free machining steels. Optical and scanning electron microscopy studies of the fractured specimens indicate that the dynamic loading response is strongly material dependent, being inlfuenced by the grain size and the presence of brittle second phase particles. Predominantly intergranular microcracks are observed in pure iron specimens having grain sizes ranging from 40 to 200 microns, whereas transgranular microcracks are observed to initiate the fracture process in 0.2% C steel of varying microstructures. The degree of dynamic fracture increases with increasing grain size in 0.2% C steel containing ferrite - pearlite microstructures. A detailed study of dynamically loaded specimens indicates that the occurrence of microfractures in 0.2% C steel is associated with second phase particles in the form of inclusions and carbides, and that the predominance of intergranular cracking in pure iron is due to its relatively low carbon content and coarse grain size. The fracture characteristics of the various materials are compared and discussed in relation to the dynamic fracture behavior of steel subjected to other methods of loading.

关键词： 显微结构   干涉   彩色照片   石墨化   碳素材料  

摘要： 在碳素材料的理化检验中,研究碳素材料的显微结构的特征具有重要的意义。本文介绍部分碳素材料在灵敏色调(色干涉)下的显微结构的彩色照片,并以此来说明它们的结构特征。试验条件:应用大型卧式金相显微镜(Neophoto),光源采用碳棒弧光源,经紫外滤光器,并用RI灵敏色片产生灵敏色调照明,采用国产GB—17°彩色胶卷摄照,彩色正片采用放大印制法。试样制备接一般金相试样的要求,经磨制、粗抛和精抛光而成,对于粉状、粒状及结构

关键词： Rare earths   Lanthanides   Recycling   Extractive metallurgy   Magnets   Catalysts   BatteriesPreview | Abstract | Full Text | PDF (449 KB) | FiguresNovember 18   2013G A MoldoveanuG A Moldoveanu   V G PapangelakisV G PapangelakisMoldoveanuMoldoveanu   PapangelakisPapangelakisMoldoveanu et al.Moldoveanu et al.Leaching of lanthanides from various weathered elution deposited oresLeaching of lanthanides from various weathered elution deposited oresG A MoldoveanuG A Moldoveanu   V G PapangelakisV G PapangelakisMoldoveanuMoldoveanu   PapangelakisPapangelakisMoldoveanu et al.Moldoveanu et al.Volume: 52   Issue: 3   pp. 257–264http://***/10.1179/1879139513Y.0000000060Keywords: Ion adsorption clays   Rare earths leaching   Rare earths desorption   Ion exchange leaching   Lanthanides   Rare earth elements Preview | Abstract | Full Text | PDF (314 KB) | FiguresNovember 18   2013D K ChibweD K Chibwe   G AkdoganG Akdogan   C AldrichC Aldrich   P TaskinenP TaskinenChibweChibwe   AkdoganAkdogan   AldrichAldrich   TaskinenTaskinenChibwe et al.Chibwe et al.Modelling of mixing   mass transfer and phase distribution in a Peirce–Smith converter modelModelling of mixing   mass transfer and phase distribution in a Peirce–Smith converter modelD K ChibweD K Chibwe   G AkdoganG Akdogan   C AldrichC Aldrich   P TaskinenP TaskinenChibweChibwe   AkdoganAkdogan   AldrichAldrich   TaskinenTaskinenChibwe et al.Chibwe et al.Volume: 52   Issue: 2   pp. 176–189http://***/10.1179/1879139512Y.0000000056Keywords: Computational fluid dynamics   Peirce–Smith converter   ModellingPreview | Abstract | Full Text | PDF (536 KB) | FiguresNovember 22   2013D K ChibweD K Chibwe   G AkdoganG Akdogan   C AldrichC Aldrich   P TaskinenP TaskinenChibweChibwe   AkdoganAkdogan   AldrichAldrich   TaskinenTaskinenChibwe et al.Chibwe et al.Modelling of mixing   mass transfer and phase distribution in a Peirce–Smith converter modelModelling of mixing   mass transfer and phase distribution in a Peirce–Smith converter modelD K ChibweD K Chibwe   G AkdoganG Akdogan   C AldrichC Aldrich   P TaskinenP TaskinenChibweChibwe   AkdoganAkdogan   AldrichAldrich   TaskinenTaskinen  

摘要： Polycrystalline materials are visualized in this paper as a statistical ensemble of microelements whose crystallographic axes are randomly, but not uniform randomly, oriented in the material system. Based on this concept the influence of internal dislocations and grain boundaries on the elastic response of such metals is discussed. The latter influence is taken into consideration by combining the grain boundary coincidence cell models of Bollmann with the relaxation technique of Weins in the case of symmetric tilt boundaries. The micromechanics theory of Axelrad and Provan is also briefly discussed to indicate where these quantitative metallurgical studies are of importance in the further development of this theory. © 1974 Maney Publishing.

关键词： Neurosecretion   Harvestman   Exocytosis   Release   Ultrastructure  

摘要： The paraganglionic plates of the harvestman, Trogulus, are neurohemal organs composed of a thick neural lamella facing a blood sinus, basal glial cells, and seven distinct types of axon terminals (A1, A2, B1, B2, B3, B4 and C) identified on the basis of elementary granule size, electron density, and structure of *** release of A1 type granules occurs by exocytosis into the extraaxonal space below the acellular neural lamella. The release of the content of C granules occurs after fragmentation into small electron dense vesicles. Clusters of these vesicles intermixed with clear vesicles pressing against the axolemma beneath the neural lamella, apparantly correspond to the sites of release.

关键词： Public Health   Collagen   Sodium   Basement Membrane   Cataract  

摘要： The peripheral exfoliation band was scraped from seventeen lenses that were removed because of senile cataract. A suspension of the exfoliation substance, negatively stained with sodium silicotungstate, was studied and compared with the sectioned exfoliation *** is concluded that the exfoliation substance probably consists of a collagen material, that perhaps comes from basement membranes.

关键词： 飞秒激光   金属纳米颗粒   微加工   femtosecond laser   metal nanoparticles   micro-processing  

摘要： 介绍了飞秒激光在高纯度金属纳米颗粒的制备及纳米颗粒的尺寸和形状的改变,玻璃内部形成基于金属纳米粒子的“三维空间选择性”析出的彩色图案的制备,有机聚合物微光子器件的制备以及光存储、光波导和光开关器件的制备等方面的应用。关键词

关键词： 光学材料   飞秒激光   SiC晶体   纳米阵列   周期结构   optical materials   femtosecond laser   SiC crystal   arrays of nanoparticles   periodic structures  

摘要： 激光诱导周期性纳米微结构在多种材料包括电介质、半导体、金属和聚合物中观察到。研究了800 nm和400 nm飞秒激光垂直聚焦于6H SiC晶体表面制备纳米微结构。实验观察到800 nm和400 nm线偏光照射样品表面分别得到周期为150 nm和80 nm的干涉条纹, 800 nm圆偏振激光单独照射样品表面得到粒径约100 nm的纳米颗粒。偏振相互垂直的800 nm和400 nm激光同时照射晶体得到粒径约100 nm的纳米颗粒阵列, 该纳米阵列的方向随400 nm激光强度增加而向400 nm偏振方向偏转。利用二次谐波的观点对以上纳米结构的形成给出了解释。关键词

关键词： 微晶玻璃   氧化亚铜纳米晶   显微结构   抗菌性能   可见光催化   glass-ceramics   Cu2O nanocrystalline   microstructure   antibacterial property   visible light driven photocatalysis  

摘要： 新型Cu2O纳米微晶玻璃具有高Cu载量、低成本和易大规模制备等特点，有望成为载银抗菌玻璃较有潜力的替代者。通过采用XRD、Raman光谱、XPS、FESEM和TEM等表征方法重点研究了不同ZnO/K2O比对SiO2-Al2O3-K2O-ZnO-P2O5-B2O3-CuO微晶玻璃显微结构的影响，并分析讨论了其结构-性能关系。结果表明，微晶玻璃中Zn与P元素会富集在Cu元素所在区域的附近，适量的ZnO能使微晶玻璃中析出的Cu2O晶粒尺寸稳定在纳米级别，并能调节微晶玻璃中Cu元素的浸出速率。Cu2O纳米微晶玻璃对大肠杆菌和金黄色葡萄球菌均具有显著的抗菌效果，并能实现对维多利亚蓝B溶液的可见光催化降解，是一种极具发展潜力的新型功能微晶玻璃材料。

关键词： 热电材料   Mg3Bi2/Mg2Sn纳米复合膜   Seebeck系数   相界面   载流子浓度   迁移率   电导率   thermoelectric material   Mg3Bi2/Mg2Sn nanocomposite film   Seebeck coefficient   phase interface   carrier concentration   mobility   conductivity  

摘要： 利用高真空磁控溅射技术, 通过高纯Mg靶和自制Mg-Bi-Sn合金靶的顺序溅射沉积, 制备了Mg3Bi2/Mg2Sn纳米复合薄膜。沉积薄膜的晶体结构和相组成由X射线衍射(XRD)图谱确定, 表面形貌和化学成分用场发射扫描电子显微镜(FESEM)和能谱仪(EDS)进行观察、测量和分析。沉积薄膜的载流子浓度和迁移率通过霍尔实验获得, 电导率和Seebeck系数由Seebeck/电阻测试分析系统进行测量。结果表明, 沉积薄膜由Mg3Bi2和Mg2Sn两相组成, 随着薄膜中Mg2Sn含量的增加, 沉积薄膜的室温载流子浓度增加而迁移率下降。在整个测试温度范围内, 随薄膜中Mg2Sn含量的增加, 薄膜Seebeck系数不断升高而电导率下降。Mg2Sn相原子含量为28.22%的沉积薄膜在155 ℃获得最高功率因子为1.2 mW·m-1·K-2。在Mg3Bi2薄膜中加入适量的Mg2Sn第二相, 可明显提升Mg3Bi2薄膜材料的功率因子。关键词