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81.
~(64)Cu,~(68)Ga,~(86)Y和~(89)Zr具备不同的半衰期和特殊生物体内性质,丰富了PET药物的多样性,为疾病的诊断和治疗提供了新的契机。近年来,金属正电子核素~(64)Cu,~(68)Ga,~(86)Y和~(89)Zr标记的药物在正电子发射计算机断层显像(PET)诊断中的应用越来越多,~(64)Cu在乏氧显像中发挥重要作用,~(68)Ga在靶向神经内分泌(NET)类肿瘤的诊断药物领域发展迅速,~(86)Y,~(89)Zr有望在免疫PET和放射免疫治疗领域发挥作用。本文主要综述金属正电子核素~(64)Cu,~(68)Ga,~(86)Y,~(89)Zr的生产与纯化,溶液配位化学以及应用方面的研究进展。 相似文献
82.
《材料与设计》2015
This study investigated the microstructure, phase transformation and mechanical property of Ni–Mn–Ga particles/Mg composites with a strong interfacial reaction between the particles and the matrix. The strong interfacial reaction was related to the large surface area and energy per unit volume of the flaky shape Ni–Mn–Ga particles that favors the reaction between the particles and matrix. The martensitic transformation behavior was largely weakened due to the interfacial reactions and thus the reduced volume fraction of Ni–Mn–Ga particles. The composites exhibited a much improved compressive strength and ductility in comparison with that of the Ni–Mn–Ga alloy. The compressive plasticity of the composites was decreased when the Ni–Mn–Ga particle content exceeded 40 wt%. In comparison with the Mg-composites with large size Ni–Mn–Ga particles, the composites with small size particles would have a much stronger interfacial reactions, which was detrimental to the phase transformation and mechanical ductility of the composites. The investigation results in this article could provide a reference for the design and preparation of the particles reinforced metal matrix functional composites. 相似文献
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85.
不同温度时效后Ni-20Cr-18W-1Mo合金晶界偏聚及力学性能研究 总被引:1,自引:1,他引:0
采用扫描电镜(SEM)、透射电镜(TEM)、电子探针(EPMA)和高温力学试验机等手段,研究了不同时效温度(200-800 °C)对Ni-20Cr-18W-1Mo高温合金的元素晶界偏聚和力学性能的影响。结果表明,硫、磷元素的晶界偏聚临界时间随时效温度升高而降低;时效温度对元素在晶界和晶内的成分分布有显著的影响;实验合金的抗拉强度和延伸率随时效温度升高而降低。分析发现,硫、磷元素在晶界中的含量随时效温度升高而增大直至两者分别在650和400 °C时达到峰值,是合金在200-600 °C区间内力学性能降低的重要原因。 相似文献
86.
Wolfram Witte Daniel Abou‐Ras Karsten Albe Gottfried H. Bauer Frank Bertram Christian Boit Rudolf Brüggemann Jürgen Christen Jens Dietrich Axel Eicke Dimitrios Hariskos Matthias Maiberg Roland Mainz Max Meessen Mathias Müller Oliver Neumann Thomas Orgis Stefan Paetel Johan Pohl Humberto Rodriguez‐Alvarez Roland Scheer Hans‐Werner Schock Thomas Unold Alfons Weber Michael Powalla 《Progress in Photovoltaics: Research and Applications》2015,23(6):717-733
The gallium gradient in Cu(In,Ga)Se2 (CIGS) layers, which forms during the two industrially relevant deposition routes, the sequential and co‐evaporation processes, plays a key role in the device performance of CIGS thin‐film modules. In this contribution, we present a comprehensive study on the formation, nature, and consequences of gallium gradients in CIGS solar cells. The formation of gallium gradients is analyzed in real time during a rapid selenization process by in situ X‐ray measurements. In addition, the gallium grading of a CIGS layer grown with an in‐line co‐evaporation process is analyzed by means of depth profiling with mass spectrometry. This gallium gradient of a real solar cell served as input data for device simulations. Depth‐dependent occurrence of lateral inhomogeneities on the µm scale in CIGS deposited by the co‐evaporation process was investigated by highly spatially resolved luminescence measurements on etched CIGS samples, which revealed a dependence of the optical bandgap, the quasi‐Fermi level splitting, transition levels, and the vertical gallium gradient. Transmission electron microscopy analyses of CIGS cross‐sections point to a difference in gallium content in the near surface region of neighboring grains. Migration barriers for a copper‐vacancy‐mediated indium and gallium diffusion in CuInSe2 and CuGaSe2 were calculated using density functional theory. The migration barrier for the InCu antisite in CuGaSe2 is significantly lower compared with the GaCu antisite in CuInSe2, which is in accordance with the experimentally observed Ga gradients in CIGS layers grown by co‐evaporation and selenization processes. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
87.
Roland Mainz Alfons Weber Humberto Rodriguez‐Alvarez Sergiu Levcenko Manuela Klaus Paul Pistor Reiner Klenk Hans‐Werner Schock 《Progress in Photovoltaics: Research and Applications》2015,23(9):1131-1143
Ga segregation at the backside of Cu(In,Ga)Se2 solar cell absorbers is a commonly observed phenomenon for a large variety of sequential fabrication processes. Here, we investigate the correlation between Se incorporation, phase formation and Ga segregation during fast selenisation of Cu–In–Ga precursor films in elemental selenium vapour. Se incorporation and phase formation are analysed by real‐time synchrotron‐based X‐ray diffraction and fluorescence analysis. Correlations between phase formation and depth distributions are gained by interrupting the process at several points and by subsequent ex situ cross‐sectional electron microscopy and Raman spectroscopy. The presented results reveal that the main share of Se incorporation takes place within a few seconds during formation of In–Se at the top part of the film, accompanied by outdiffusion of In out of a ternary Cu–In–Ga phase. Surprisingly, CuInSe2 starts to form at the surface on top of the In–Se layer, leading to an intermediate double graded Cu depth distribution. The remaining Ga‐rich metal phase at the back is finally selenised by indiffusion of Se. On the basis of a proposed growth model, we discuss possible strategies and limitations for the avoidance of Ga segregation during fast selenisation of metallic precursors. Solar cells made from samples selenised with a total annealing time of 6.5 min reached conversion efficiencies of up to 14.2 % (total area, without anti‐reflective coating). The evolution of the Cu(In,Ga)Se2 diffraction signals reveals that the minimum process time for high‐quality Cu(In,Ga)Se2 absorbers is limited by cation ordering rather than Se incorporation. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
88.
通过恒温水浴完全气化样品,建立了用毛细管气相色谱法测定液化石油气中二甲醚、甲醇及甲缩醛含量的方法。采用PLOT/Q(30 m×0.53 mm×40μm)毛细管柱、热导池检测器,以面积校正归一化法计算杂质含量。结果表明:该方法操作简单,实用性强,重复性好,可以用于液化石油气中杂质含量的快速分析。 相似文献
89.
稀散元素是铅锌矿石中重要的伴生元素,为了综合利用铅锌矿资源,在地质、选矿上经常要考查稀散元素镓、锗、铟、铊的含量。研究了利用电感耦合等离子体质谱法测定铅锌矿中镓、铟、锗、铊4种稀散元素,选取了最佳仪器分析条件,通过在线加入内标校正基体效应和接口效应,检出限分别为0.02μg·g-1、0.01μg·g-1、0.03μg·g-1和0.05μg·g-1,相对标准偏差(RSD)为0.85%~2.84%,回收率在93.3%~102.3%之间,明显优于其他分析方法。该方法样品前处理简便、快捷,测定结果准确,令人满意。 相似文献
90.
非均匀软岩蠕变机理分析 总被引:5,自引:0,他引:5
为了对工程围岩的蠕变现象进行解释,探明软岩的蠕变本质,根据岩石压缩过程中变形、弱化本构关系以及变形与承载能力的关系,采用岩石最弱断面并联微元体模型,对非均匀软岩的衰减蠕变和非衰减蠕变机理进行了分析,研究表明,非均匀性岩石内部各点承载能力不同使得变形后岩石内部各点屈服弱化不同步,又由于岩石晶体内部空位或杂质的扩散,二者共同作用导致岩石蠕变.通过对截面积相同,高径比分别为1.5和2.5的页岩岩样进行蠕变试验,验证了岩石的非均匀性是造成岩石蠕变的一个不可忽视的重要因素. 相似文献