检索结果-南通市图书馆

Martensitic Transformation in Fe-Mn-si Based Shape Memory Alloys

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 1999年第2期15卷 111-116页

作者： T. Y. Hsu (XU Zuyao)(Shanghai Jiao Tong University, Shanghai 200030, China) Shanghai Jiao Tong University Shanghai 200030 China Chinese Academy of Sciences China

The critical driving force for martensitic transformation fcc ( gamma ) yields hcp ( epsilon ) in ternary Fe-Mn-si alloys increases with the content of Mn and decreases with that of si. Thermodynamical prediction of M//s in ternary Fe-Mn-si alloys was established. The fcc ( gamma ) yields hcp ( epsilon ) martensitic transformation in Fe-Mn-si is a semi-thermoelastic and the nucleation process does not strongly depend on soft mode. Nucleation occurs directly through an overlapping of stacking fault rather than pole mechanism, and it is suggested that stacking fault energy (SFE) is the main factor controlling nucleation. Based on the phenomenological theory of martensite crystallography, a shuffle on (0001)//h//c//p plane is required when d//1//1//1 does not equal d//0//0//0//2. The derived principal strain in Bain distortion is smaller, i, e., more reasonable than the values given by Christian. Alloying elements strengthening the austenite, lowering SFE of gamma phase and reducing T//N** gamma temperature may be beneficial to shape memory effect of Fe-Mn-si based alloys. Accordingly, Fe-Mn-si-RE and Fe-Mn-si-Cr-N (or Fe-Mn-si-Ni-Cr-N) are worthy to be recommended as shape memory materials with improved shape memory effect. (Edited author abstract) 48 Refs.

关键词： Mn Martensitic Transformation in Fe-Mn-si Based Shape Memory Alloys Fe si

Process of aluminum dross recycling and life cycle assessment for Al-si alloys and brown fused alumina

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2010年第11期20卷 2155-2161页

作者：洪建平王俊陈海 孙宝德李家镜陈冲 State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University Institute of Marine Materials Science and Engineering Shanghai Ocean University

In 2008,around 596 000 t of aluminum dross was generated from secondary aluminum industry in China;however,it was not sufficiently recycled yet.Approximately 95% of the Al dross was land filled without innocent treatment.The purpose of this work is to investigate Al dross recycling by environmentally efficient and friendly methods.Two methods of Al dross recycling which could utilize Al dross efficiently were presented.High-quality aluminum-silicon alloys and brown fused alumina(BFA) were produced successfully by recycling Al dross.Then,life cycle assessment(LCA) was performed to evaluate environmental impact of two methods of Al dross recycling process.The results show that the two methods are reasonable and the average recovery rate of Al dross is up to 98%.As the LCA results indicate,they have some advantages such as less natural resource consumption and pollutant emissions,which efficiently relieves the burden on the environment in electrolytic aluminum and secondary aluminum industry.

关键词：生命周期评估回收过程棕刚玉硅合金铝渣再生铝工业工艺 si

The thermal conductivity of the Earth's core and implications for its thermal and compositional evolution

在线全文

学校读者我要写书评

暂无评论

National Science Review 2021年第4期8卷 18-20页

作者： Kenji Ohta Kei Hirose Department of Earth and Planetary Sciences Tokyo Institute of Technology Earth-Life Science Institute Tokyo Institute of Technology Department of Earth and Planetary Science The University of Tokyo

The thermal conductivity of iron alloys is a key to understanding the mechanism of convection in the Earth’s liquid core and its thermal history. The Earth’s magnetic field is formed by a dynamo action that requires... 详细信息

关键词： ELECTRICAL-REsiSTIVITY HIGH-PRESSURE IRON ALLOYS si NI

A NEW STRUCTURE OF SMALL INTENSELY FLUORESCENT CELLS IN SUPERIOR MESENTERIC GANGLION OF HUMAN FETUS

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Medical Journal 1995年第1期108卷 52-54页

作者：袁维中王宇一 Department of Histology and Embryology Inner Mongolia Medical College Huhhot 010059

Superior mesenteric ganglia of six fetuses (35-40 weeks old) were investigated by histochemical fluorescent method. In addition to solitary siF cells and clusters of siF cells reported previously, a new structure of siF cells was found and named ''siF-cell nodule''. The siF-cell nodule was composed of a large number of siF cells and was encapsulated by dense connective tissue. Some blood vessels and nerve fibers entered the nodule. Based on the morphology, we speculated that siF-cell nodule might be an endocrine gland.

关键词： si A NEW STRUCTURE OF SMALL INTENSELY FLUORESCENT CELLS IN SUPERIOR MESENTERIC GANGLION OF HUMAN FETUS cell In

Optical saturation characteristics of dual-and single-injection Ge-on-si photodetectors

在线全文

学校读者我要写书评

暂无评论

Chinese Optics Letters 2018年第7期16卷 78-81页

作者：崔积适白博文杨丰赫周治平 State Key Laboratory of Advanced Optical Communication Systems and Networks School of Electronics Engineering and Computer Science Peking University

The optical saturation characteristics in the germanium-on-silicon（Ge-on-si） photodetector are studied for the first time, to the best of our knowledge. The relationship between the optical saturation characteristics and the optical field distribution in the Ge layer is illustrated by the simulation. This theory is verified by comparative experiments with single-injection and dual-injection structures. The dual-injection photodetector with a more balanced and uniform optical field distribution has a 13% higher responsivity at low optical power and 74.4%higher saturation current at 1550 nm. At higher optical power, the bandwidth of the dual-injection photodetector is five times larger than that of the single-injection photodetector.

关键词： Ge Optical saturation characteristics of dual-and single-injection Ge-on-si photodetectors si

Ti-Al共掺杂si薄膜的光电性能增强机理研究

在线全文

学校读者我要写书评

暂无评论

功能材料 2023年第10期54卷 10021-10029,10038页

作者：陈玉杰杨洪旺林宇蓓邝向军温才西南科技大学数理学院四川绵阳621010 西南科技大学材料与化学学院四川绵阳621010

Ti超掺杂si(si:Ti)薄膜是通过脉冲激光的非平衡作用,在si中掺入超固溶度3个数量级以上的高浓度Ti杂质形成。它摆脱了si禁带宽度的限制,具有优异的亚带隙近红外(λ=1100~2500 nm)光吸收性能。通过真空电子束蒸发结合紫外纳秒激光熔融的方... 详细信息

Ti超掺杂si(si:Ti)薄膜是通过脉冲激光的非平衡作用,在si中掺入超固溶度3个数量级以上的高浓度Ti杂质形成。它摆脱了si禁带宽度的限制,具有优异的亚带隙近红外(λ=1100~2500 nm)光吸收性能。通过真空电子束蒸发结合紫外纳秒激光熔融的方式,制备了Ti-Al共掺杂si(si:(Ti-Al))薄膜,以进一步提高薄膜的亚带隙近红外光吸收性能,更好地满足近红外器件的需求。研究结果表明,si:(Ti-Al)薄膜的薄层电阻,由本征单晶si衬底的10^(4)Ω/square量级降低至10^(2)Ω/square量级,与si:Ti薄膜一致。但是,si:(Ti-Al)薄膜在亚带隙近红外波段的吸光度,较本征单晶si衬底平均提高了7倍,最大提高了一个数量级(λ=1800 nm处);较si:Ti薄膜平均提高了33%,最大提高了57.2%(λ=1200 nm处)。表面形貌分析表明,si:(Ti-Al)薄膜的二次激光加工降低了表面光反射。薄膜成分分析表明,si:(Ti-Al)薄膜中存在Tisi_(2)和AlTi。Tisi_(2)的存在表明,Ti杂质被激活后与si原子键合。AlTi的存在并结合能带结构分析表明,si:(Ti-Al)薄膜中通过改变Al补偿杂质浓度,调节费米能级位置,从而增强了亚带隙近红外光吸收性能。

关键词：纳秒激光共掺杂 si 电学性能光吸收性能费米能级

Heavy ion micro-beam study of single-event transient(SET) in si Ge heterjunction bipolar transistor

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2017年第12期60卷 120-122页

作者： Jinxin ZHANG Hongxia GUO Fengqi ZHANG Chaohui HE Pei LI Yunyi YAN Hui WANG Linxia ZHANG School of Aerospace Science and Technology Xidian University Xinjiang Technical Institute of Physics & Chemistry Chinese Academy of Sciences Northwest Institution of Nuclear Technology School of Energy and Power Engineering Xi'an Jiaotong University

silicon-germainum heterojunction bipolar transistor(si Ge HBT)has been demonstrated to be suitable in extreme environment because of its superior temperature characteristics which can operate from 43 K to 400 K[1].In addition,outstanding hardness to both total ionizing dose(TID)radiation and displacement damage make si Ge HBT technology particularly attractive for space

关键词： si Heavy ion micro-beam study of single-event transient Ge HBT SET

Effect of si content on impact-abrasive wear resistance of Al2O3p/steel composites prepared by squeeze casting

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research(International) 2018年第9期25卷 984-994页

作者： De-hong Lu Hai-zhou Li Bo Ren Faculty of Materials Science and Engineering Kunming University of Science and TechnologyKunming 650093 Yunnan China

The 40Cr steel matrix composites were reinforced with Al203 particulates （Al2O3p） through si adding to improve the impact-abrasive wear resistance, in which si powder ranging up to 25% of the AlzO3p weight was added into the Al2O3p preforms; then, the composites were fabricated by squeeze casting. For all composites, alumina particles are evenly distributed, and si powder is dissolved in the matrix. Without si powder addition, the 40Cr steel matrix contains only pearlite; however, ferrite appears and increases with si powder addition. In the impact-abrasive wear tests, the impact frequency is 80 min^-1 and the impacting energy is 2 J. With increasing si powder, the wear of the composites first decreases obviously, reaches the minimum at 10% and then increases. The effect of si addition on the wear resistance can be attributed to two reasons： one is increasing the hardness of the matrix, and the other is improving the interfacial bonding between Al2O3p and steel. The wear mechanism of the composites is abrasive wear when the si powder is 〈 10 wt%. Otherwise, it is a mixed mode of abrasive and delamination wear.

关键词： Steel matrix composite si Impact-abrasive wear Wear mechanism Al2O3 particulate Squeeze casting

Semi-solid characteristics and thixoforming of hypereutectic Al-si alloy

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2000年第3期10卷 309-313页

作者： LIU Chang ming(刘昌明) HE Nai jun(何乃军) LI Hua ji(李华基) Chongqing Univ Sch Mech Engn State Key Lab Mech Transmiss Chongqing 400044 Peoples R China

Effects of processing parameters on microstructure evolutions by mechanical stirring, procedures for obtaining thixotropy in semi solid slurries, and procedure for thixoforging component, were investigated in hypereutectic Al si alloy. It is shown that 605 ℃ was the proper temperature for stirring treatment of this alloy, at which the coarse and plate primary si crystals were effectively changed to globular crystals with a mean diameter of 200 μm after 50 min stirring, that billets with excellent thixotropy were obtained after 50 min remelting at 575 ℃, in which solid fraction of matrix and primary si crystals was about 60%, and that a perfect near net shape component of disc casting was obtained by thixoforging.

关键词： hypereutectic Al si alloy primary si crystals thixoforming