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Solid liquid Mixed Casting of Al-Si Alloy

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Journal of Central South University 2000年第3期12卷 133-135页

作者： chen, ZH Kang, ZT Cent S Univ Technol Dept Mat Sci & Engn Changsha 410083 Peoples R China

The paper presents a novel material preparation technology—Solid liquid mixed casting technology. In the technology, large amounts of homogeneous alloy powder or heterogenous powder with perfect wettability are added into the superheated melt. After strong agitation, the mixed melt can be cast or hot processed. Applying solid liquid mixed casting, three kinds of Al Si alloys were investigated. The results show that, when the mass of powder accession to alloy melt is about 1, the mean size of primary Si in hyper eutectic alloy can be controlled at less than 5 μm; and the mean grain size of α phase in hypo eutectic alloy is less than 10 μm. This technology has the advantage of preparing material with very fine microstructure by fairly simple casting process, and may be a new practicable and valuable metal preparation technology.

关键词： solid liquid mixed casting powder melt Document code:A

Risk Identif ication and Prevention to the Intelligent Network Implementation

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China Communications 2009年第1期6卷 99-103页

作者： Zhao Yumei chen Xiuyu Beijing University of Posts and Telecommunications China

Risk management are set of processes which include risk identification, risk analysis, risk evaluation and risk implementation. Risk exists throughout the entire life cycle of the project. It is an important guarantee for the success of the project to establish a good risk management mechanism and the risk-based decision-making mechanism. Personal communication tries to connect various telecommunication services to people, one of the key technologies to realise personal communication is to establish an advanced intelligent network—a kind of communication network that can provide and deal with the intelligent new businesses. It is an important guarantee for the success of the project to establish a good risk management mechanism and the risk-based decision-making mechanism.

关键词： risk identification IN implementation risk management

Dynamics of the higher-order structure of chromatin

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Protein & Cell 2010年第11期1卷 967-971页

作者： Ping chen Guohong Li Institute of Biophysics Chinese Academy of SciencesBeijing 100101China

Eukaryotic DNA is hierarchically packaged into chromatin to fit inside the *** of the chromatin structure plays a critical role in transcriptional regulation and other biological processes that involve DNA,such as DNA replication and DNA *** factors,including histone variants,histone modification,DNA methylation and the binding of non-histone architectural proteins regulate the structure of *** the structure of nucleosomes,the fundamental repeating unit of chromatin,is clear,there is still much discussion on the higher-order levels of chromatin *** the structural details and dynamics of higher-order chromatin fibers is therefore very important for understanding the organization and regulation of gene ***,we review studies on the dynamics of chromatin higherorder structure and its relationship with gene transcription.

关键词： chromatin higher-order structure dynamics transcriptional regulation

CALCULATION OF THE SECOND-ORDER OPTICAL SUSCEPTIBILITIES OF SOME BENZENE DERIVATIVE MOLECULES AND CRYSTALS

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Chinese Physics Letters 1990年第6期7卷 268-271页

作者： LIN Shujie chen Chuangtian Fujian Institute of Research on the Structure of Matter Academia SinicaFuzhou350002

The microscopic and macroscopic second-order optical susceptibilities of ten benzene derivative molecules and three crystals were calculated and discussed,basing on the nonlinear optical active group theory.

关键词： theory derivative benzene

Correlation of isothermal bainite transformation and austenite stability in quenching and partitioning steels

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Journal of Iron and Steel Research International 2017年第11期24卷 1095-1103页

作者： Shan chen Guang-zhen Wang Chun Liu chen-chong Wang Xian-ming Zhao Wei Xu State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819LiaoningChina

The possible decomposition of metastable austenite during the partitioning process in the high end quenching and partitioning （Q＆P） steels is somewhat neglected by most researchers. The effects of primary martensite and alloying elements including manganese, cobalt and aluminum on the isothermal decomposition of austenite during typical Q＆P process were studied by dilatometry. The transformation kinetics was studied systematically and resulting microstruc tures were discussed in details. The results suggested that the primary martensite decreased the incubation period of isothermal decomposition by accelerating the nucleation process owing to dislocations especially on phase and grain boundaries. This effect can be eliminated by a flash heating which recovered dislocations. Co addition significantly promoted the bainite transformation during partitioning while A1 and Mn suppressed the isothermal bainite transformation. The bainite transformation played an important role in carbon distribution during partitioning, and hence the amount and stability of austenite upon final quenching. The bainite transformation during partitioning is an important factor in optimizing the microstructure in Q＆P steels.

关键词： Bainit e transformation Isothermal decomposition Retained austenite Quenching and partitioning steel Carbon partitioning

Preparation and Characterization of Multiester Derivative from Plant Oil as Base Stock for Biolubricants

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China Petroleum Processing & Petrochemical Technology 2020年第2期22卷 122-128页

作者： Li Xiong chen Ligong Engineering Research Center for Waste Oil Recovery Technology and Equipment of Ministry of Education Chongqing Technology and Business UniversityChongqing 400067

As an alternative to petroleum-based lubricants, which are harmful to the environment in excessive amounts, a biodegradable multiester derivative(OFANE) was obtained from plant oil through a chemical modification process with four steps as follows: hydrolysis, esterification, epoxidation, and ring-opening reaction. The physical and chemical properties of OFANE, such as viscosity, acid value, pour point, evaporation loss, and oxidation induction time were measured. Results showed that OFANE had good low-temperature fluidity, thermal-oxidative stability, and tribological properties. The tribological properties of OFANE with dimeric acid additive were evaluated. The final biodegradation experiment indicated that OFANE had excellent biodegradability. The prepared OFANE showed great potential as substitute for petroleum-based lubricating base oils.

关键词： plant oil multiester derivative lubricant base oil physicochemical property tribological property

Revisiting greenness of ionic liquids and deep eutectic solvents

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Green Chemical Engineering 2021年第2期2卷 174-186页

作者： Yu chen Tiancheng Mu Department of Chemistry and Material Science Langfang Normal UniversityNO.100 Aimin West RoadAnci DistrictLangfang065000HebeiChina Department of Chemistry Renmin University of ChinaNO.59 Zhongguancun StreetHaidian DistrictBeijing100872China

Green solvents are one of the hot topics of green *** liquids(ILs)and deep eutectic solvents(DESs)are deemed as green solvents to a certain extent,and they have been applied in many areas,such as dissolution,separation,catalysis,electrochemistry and material ***,the greenness of ILs and DESs should be revisited because more and more evidences have shown that they are not always *** this perspective,besides the reported merits,the disadvantages and problems of some ILs and DESs,such as instability,volatility,hygroscopicity,toxicity,flammability,regenerability,cost,energy consumption and impurities are ***,13 strategies to avoid the disadvantages of ILs and DESs and to increase the greenness are *** of the greenness of ILs and DESs is further *** perspective provides some new viewpoints on the greenness of ILs and DESs.

关键词： Green solvents Ionic liquids Deep eutectic solvents Greenness Stability

Infrared Nano-Imaging of Electronic Phase across the Metal–Insulator Transition of NdNiO_(3) Films

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Chinese Physics Letters 2022年第7期39卷 58-62页

作者： Fanwei Liu Sisi Huang Sidan chen Xinzhong chen Mengkun Liu Kuijuan Jin Xi chen State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics Tsinghua UniversityBeijing 100084China Institute of Physics Chinese Academy of SciencesBeijing 100190China Department of Physics and Astronomy Stony Brook UniversityStony BrookNY 11794USA

NdNiO_(3) is a typical correlated material with temperature-driven metal–insulator transition. Resolving the local electronic phase is crucial in understanding the driving mechanism behind the phase transition. Here we present a nano-infrared study of the metal–insulator transition in NdNiO_(3) films by a cryogenic scanning near-field optical microscope. The NdNiO_(3) films undergo a continuous transition without phase coexistence. The nano-infrared signal shows significant temperature dependence and a hysteresis loop. Stripe-like modulation of the optical conductivity is formed in the films and can be attributed to the epitaxial strain. These results provide valuable evidence to understand the coupled electronic and structural transformations in NdNiO_(3) films at the nano-scale.

关键词： red Insulator Transition of NdNiO_(3)Films Infrared Nano-Imaging of Electronic Phase across the Metal

On the New Initiative for Responsible Space Behaviors Proposed by United Kingdom,United States,and Other States

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Space(Science & Technology) 2023年第1期3卷 248-255页

作者： Guoyu Wang Junzhe chen Academy of Air Space Policy and LawSchool of LawBeijing Institute of TechnologyBeijingChina

In December 2020,the Draft Resolution on Reducing Space Threats through Norms,Rules and Principles of Responsible Behaviours proposed by the United Kingdom,United States,and other States was adopted at the UN General Assembly(hereafter referred to as the“New Initiative for Responsible Space Behaviours”).Nevertheless,it does not mean that the international community would achieve the expected breakthroughs and progress on the topic of preventing an arms race in outer *** methodology of“identifying threats-characterising behaviors(responsible/irresponsible)-formulating rules”proposed by the Initiative seems reasonable;however,it might bring more unexpected uncertainties than it is supposed to *** approach could also be found in the Defense Space Strategy promulgated by the United States in *** pros and cons of this Initiative should be calmly and objectively analyzed to avoid a political deadlock in formulating rules of *** should insist on identifying the threats and risks faced by the international community as a whole rather than that by individual States and interest groups,and reexamine the dichotomy of“responsible/irresponsible behaviors,”focus on the identification and interpretation of rule of international law related to space security so as to reach a consensus on the insufficiency of lex lata and subsequently lay the foundation for the formulation of effective new rules for arms control in outer space.

关键词： outer breakthrough hereafter