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SOLUBILITY OF NITROGEN IN MOLTEN GRAY CAST IRON

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Acta Metallurgica Sinica(English Letters) 1992年第7期5卷 71-73页

作者： zhai qijie, hu hanqi, University of Science and Technology Beijing, Beijing, China hu hanqi, Professor, Faculty of Foundry, University of Science and Technology Beijing, Beijing 100083, China

The expressions of the dependence of nitrogen solubility in molten gray cast iron on the temperature and composition of the melt were proposed under the condition of foundry practice. Three gray cast iron specimens wi... 详细信息

关键词： gray cast iron nitrogen solubility

Effect of Process Factors on Microstructure of Semisolid Continuous Casting Billets

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International Journal of Minerals,Metallurgy and Materials 2000年第4期14卷 242-245页

作者： Shuming Xing, qijie zhai, hanqi hu ( Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China School of Material Science and Engineering, Shanghai University, Shanghai 200072, China Material Science and Engineering School, Univer Department of Mechanical Engineering Tsinghua University Beijing 100084 China School of Material Science and Engineering Shanghai University Shanghai 200072 China Material Science and Engineering School University of Science and Technology Beijing Beijing 100083 China

Semisolid continuous casting (SSCC) is a new technology to produce billets for semisolid metal forming (SSMF). The effect of process factors, such as pouring temperature, stirring rate, preheating temperature and thermal conductivity of stirring chamber, on the microstructure of SSCC billets was studied by means of the factorial experimental method. The results show that the microstructure of SSCC billets can be controlled by the above-mentioned four process factors. In order to obtain fine and rounded granular grains in an SSCC billet, the pouring temperature, preheating temperature and stirring rate should be kept in a moderate range, and the thermal conductivity of stirring chamber should be high. The regression equations with the process factors connecting the microstructure was also set up based on experimental data.

关键词： semisolid metal continuous casting process factors microstructure Metallurgy

EFFECT OF NITROGEN ON MATRIX STRUCTURE OF GRAY CAST IRON

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Acta Metallurgica Sinica(English Letters) 1993年第6期6卷 370-372页

作者： zhai qijie hu hanqi University of Science and Technology Beijing,China associate professor,Faculty of Foundry,University of Science and Technology Beijing,Beijing 100083,China

Effect of nitrogen on matrix structure of 3 different varieties of gray cast iron,i.e., sub-eutectic Fe-C-Si,near-eutectic Fe-C-Si and Fe-C-Si-Mn,has been investigated. The eutectie colony structure of gray cast iron may be refined,the pearlite content increased and the micro-hardness of pearlite and ferrite raised with an addition of *** influ- ence of nitrogen on the transformation temperature of the equilibrium and non-equilibrium phases,as well as,the solution of nitrogen in ferrite and cementite seem to be the major rea- sons to strengthening the matrix structure of gray cast iron.

关键词： nitrogen gray cast iron matrix structure microhardness solid solution

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半固态连铸过程拉漏(断)机理研究

特种铸造及有色合金 2002年第S1期22卷 254-257页

作者：邢书明李亚敏马静陈维视翟启杰胡汉起杨秀斌杨日增贺丽荣杨天增清华大学机械工程系北京100084 河北科技大学北京科技大学武安市贺进建材机械厂

利用自行设计制造的半固态连铸机对Fe Cr C系及Fe Mn C系合金进行了半固态连铸试验。着重研究了工艺参数对拉漏及拉断现象的影响 ,探讨了拉漏拉断的条件及机理 ,提出了防止拉漏拉断的技术途径。

关键词：半固态连铸拉漏拉断机理

Designing Electronic Structures of Multiscale Helical Converters for Tailored Ultrabroad Electromagnetic Absorption

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Nano-Micro Letters 2025年第1期17卷 439-455页

作者： Zhaobo Feng Chongbo Liu Xin Li Guangsheng Luo Naixin zhai Ruizhe hu Jing Lin Jinbin Peng Yuhui Peng Renchao Che Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle School of Environmental and Chemical EngineeringNanchang Hangkong UniversityNanchang 330063People’s Republic of China School of Physics and Materials Nanchang UniversityNanchang 330031People’s Republic of China Key Laboratory of Nondestructive Testing Ministry of EducationNanchang Hangkong UniversityNanchang 330063People’s Republic of China Laboratory of Advanced Materials Shanghai Key Lab of Molecular Catalysis and Innovative MaterialsAcademy for Engineering and TechnologyFudan UniversityShanghai 200438People’s Republic of China

Atomic-scale doping strategies and structure design play pivotal roles in tailoring the electronic structure and physicochemical property of electromagnetic wave absorption(EMWA)***,the relationship between configuration and electromagnetic(EM)loss mechanism has remained ***,drawing inspiration from the DNA transcription process,we report the successful synthesis of novel in situ Mn/N co-doped helical carbon nanotubes with ultrabroad EMWA *** calculation and EM simulation confirm that the orbital coupling and spin polarization of the Mn–N4–C configuration,along with cross polarization generated by the helical structure,endow the helical converters with enhanced EM *** a result,HMC-8 demonstrates outstanding EMWA performance,achieving a minimum reflection loss of−63.13 dB at an ultralow thickness of 1.29 *** precise tuning of the graphite domain size,HMC-7 achieves an effective absorption bandwidth(EAB)of 6.08 GHz at 2.02 mm ***,constructing macroscale gradient metamaterials enables an ultrabroadband EAB of 12.16 GHz at a thickness of only 5.00 mm,with the maximum radar cross section reduction value reaching 36.4 dB *** innovative approach not only advances the understanding of metal–nonmetal co-doping but also realizes broadband EMWA,thus contributing to the development of EMWA mechanisms and applications.

关键词： Metal-nonmetal co-doping 3d-2p orbital coupling Spin polarization Helical structure Broadband EM wave absorption

EFFECT OF NITROGEN ON GRAPHITE MORPHOLOGY IN GRAY CAST IRON

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Acta Metallurgica Sinica(English Letters) 1993年第8期6卷 151-155页

作者： zhai qijie hu hanqi University of Science and Technology Beijing,Beijing,China Faculty of Foundry,University of Science and Technology Beijing,Beijing 100083,China Beijing Univ of Science and Technology Beijing China

The distribution of N and morphology of graphite in gray cast iron containing N were studicd by adopting the man-made specimens of Fe-C-Si-Mn alloys with some N added. The N adsorbed along the interfaces between graphite and matrix together with solid- solutioned in graphite is believed to be the principal cause of morpholongical variation of graphite.

关键词： gray cast iron graphite morphology N

Cementite Decomposition in Spherical Graphite Iron by Electropulsing

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Journal of Materials Science & Technology 2009年第2期25卷 199-202页

作者： Qingchun Li Cuowei Chang qijie zhai Department of Materials and Chemical Engineering Liaoning University of Technology Jinzhou 121001 China Department of Materials Science and Engineering Shanghai University Shanghai 200072 China

The influence of electropulsing on cementite decomposition in the spherical graphite iron has been studied. The results indicated that the cementite was decomposed in a short time by high current density electropulsing. With increasing electropulsing time, the in situ nucleation of graphite in cementite was accompanied with the quick decomposition of cementite. The dislocation accumulation adjacent to the cementite and the quick diffusion of carbon atom by electropulsing were main reasons for the quick decomposition of cementite. The in situ nucleation of graphite in the cementite resulted from the dislocation climbing crossing the cementite lamellae.

关键词： Pulse electric current Spherical graphite iron Cementite Decomposition

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区域医疗系统抗震韧性综述

哈尔滨工业大学学报 2025年第1期57卷 1-12页

作者：裴顺顺翟长海胡杰结构工程灾变与控制教育部重点实验室(哈尔滨工业大学) 哈尔滨150090 土木工程智能防灾减灾工业和信息化部重点实验室(哈尔滨工业大学) 哈尔滨150090

韧性作为一种新的灾害风险管理理念,已成为防灾减灾领域的研究热点,考虑到医疗系统在城市运行和灾后救援中的重要作用,在地震期间和之后,区域医疗系统应该具有足够的韧性,并提供连续的医疗服务。如何综合考虑区域范围内多家医院和交通... 详细信息

韧性作为一种新的灾害风险管理理念,已成为防灾减灾领域的研究热点,考虑到医疗系统在城市运行和灾后救援中的重要作用,在地震期间和之后,区域医疗系统应该具有足够的韧性,并提供连续的医疗服务。如何综合考虑区域范围内多家医院和交通系统的安全性、应急响应能力、多系统的整合与协作,有效评估区域医疗系统的抗震韧性水平,并提出科学的改进建议,对建设韧性城乡具有重要的理论意义。本文通过梳理国内外文献,阐明了区域医疗系统韧性的概念和内涵,总结了地震后短期应急和长期修复两个阶段韧性评估的重点,归纳了现有区域医疗系统韧性的评估框架,从医院集群系统、面向医疗的交通系统、应急医疗服务系统和医疗-交通耦合系统4个方面阐述了现有评估方法。区域医疗系统韧性的研究旨在提高其面对灾害时的抵抗性、短期适应性和长期恢复性,这些研究对于满足紧急和日常的医疗需求以及指导灾后恢复具有重要意义。目前区域医疗系统抗震韧性的研究取得了一些进展,但仍然存在一些挑战,本文最后展望了未来的研究方向。

关键词：区域医疗系统单体医院交通系统抗震韧性功能评估恢复时间

Review of grain ref inement methods for as-cast microstructure of magnesium alloy

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China Foundry 2009年第2期6卷 93-103页

作者： Song Changjiang Han Qingyou zhai qijie Shanghai Key Laboratory of Modern Metallurgy ＆ Materials Processing Shanghai University Shanghai 200072 China Mechanical Engineering Technology Department Purdue University West Lafayette IN 47907 USA

As the lightest structural metal,Mg and Mg-based alloys have great potential applications in the aerospace,automotive and nuclear ***,such applications have been limited by low ductility and ***,small grain sized structure can synchronously improve its ductility and ***,universally reliable grain ref inement techniques for the magnesium alloys are still under investigation and some are in strong *** paper presents a brief review of development of grain ref inement methods for magnesium alloys,which would contribute to a better understanding of the factors controlling grain ref inement and provide an outlook of future research in this fi eld.

关键词： magnesium alloy grain refinement microstructure