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Study on alkali mechanical activation for recovering rare earth from waste fluorescent lamps

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Journal of Rare Earths 2018年第1期36卷 108-112页

作者： Ling He wen ji Yanwei Yin Weimin Sun State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of Technology School of Materials Science and Engineering Lanzhou University of Technology

Recycling of rare earth from waste fluorescent lamps is becoming increasingly important in future sustainable development. However, cerium and terbium are usually difficult to recover due to the stable spinel structure. In the research, alkali mechanical activation was innovatively used to pretreat the waste phosphors for recovering rare earths. The effect of alkali mechanical activation on the structural changes of waste phosphors was explored using X-ray diffraction （XRD） and Fourier transform infrared spec- troscopy （FFIR）. Meanwhile, the effects of different parameters including milling speed, activation time, and amount of alkali on the leaching rates of rare earth were investigated. The rare earth elements re- covery rates are observed to increase rapidly, particularly with increases in rotational speed and acti- vation time. Under optimal conditions, the maximum leaching rates of Ce and Tb reach 85.0% and 89.8%, respectively. And the total recovery rates of rare earth reach 95.2%. All the results indicate that alkali mechanical activation can effectively destroy the spinel structure and produce substantial physico- chemical changes. These changes lead to the easy dissolution of rare earths in acid solution, and greatly improve the leaching of cerium and terbium.

关键词： Rare earthSpinel structureRecovery rateAlkali mechanical activationWaste phosphorsRare earths

Kinetics and fractionation of hydrogen isotopes during gas formation from representative functional groups

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Petroleum Science 2021年第4期18卷 1021-1032页

作者： Shuang-Fang Lu Guo-Qi Feng ming-Li Shao ji-Jun Li Hai-Tao Xue min Wang Fang-wen Chen wen-Biao Li Xiao-Ting Pang aResearch Institute of Unconventional Oil&Gas and New Energy China University of PetroleumQingdaoShandong 266580China Exploitation and Development Research Institude of jilin Oilfield Company CNPCSongyuanJilin138000China

A gold tube simulation device was used to study the cleavage of representative compounds into *** goal of this study is to investigate hydrogen isotope composition change of gaseous hydrocarbons during *** chromatography and isotopic analyses were conducted to determine how the yield of natural gas components and their hydrogen isotopic composition were related to experimental temperature and heating rate.A chemical kinetic model for the generation of each component of the natural gas and for the hydrogen isotopic fractionation was established and calibrated based on the *** indicate that the hydrogen isotopic fractionation during the evolution of various gas-forming organic materials can be satisfactorily described by chemical kinetic *** regular methane generation,the reactions at low-activation-energy region had a greater contribution than the high-activation-energy *** the reactions with high-activation-energy region had greater contribution of deuterium-rich *** with carbon isotope fractionation,this results in a greater hydrogen isotopic fractionation,which is more sensitive to changes in *** study lays a foundation for further investigations of genesis and maturity of natural gas provided by hydrogen isotopic *** also provides fundamental knowledge for investigating the filling history of natural gas reservoir and for identifying.

关键词： Gas-forming compounds Pyrolysis Hydrogen isotopes Fractionation Chemical kinetics

Hydrothermal Synthesis and Crystal Structure of a Heterometallic Cu/Cd Complex with H_2dipic(Pyridine-2,6-dicarboxylic Acid)

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Chinese Journal of Structural Chemistry 2006年第10期25卷 1250-1254页

作者： XUE Lin CHE Yun-Xia ZHENG ji-min Department of Chemistry Nankai University Tianjin 300071 China

A new heterometallic complex {[Cu（pic）2（H2O）2][Cd2（Hdipic）2（H2O）2Cl2]}n （Mr = 1007.73） has been synthesized under hydrothermal condition and characterized by single-crystal X-ray diffraction. It crystallizes in triclinic, space group PI^- with a = 5.8397（4）, b = 9.8664（7）, c = 14.1739（10） °A, α= 82.0150（10）, β = 80.4540（10）, γ= 82.3570（10）°, Z= 1, V= 792.47（10）°A^3, Dc = 2.112 g/cm^3,μ（MoKα） = 2.247 mm^-1, F（000） = 495, the final R = 0.0232 and wR = 0.0644 for 2748 observed reflections （I〉 2σ（I））. In the complex, seven-coordinated·Cd ions form a zigzag chain based on the alternated dinuclear Cd units. The neutral [Cu（pic）2（H2O）2] units are located at the centers of the inter space and fasten to the 1-D chain by hydrogen bonds.

关键词： copper cadmium heterometallic dinuclear hydrothermal coordination polymer

Crystal Structure of a Nickel(II) Complex with Asymmetric _L-Histidine Ligand

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Chinese Journal of Structural Chemistry 2006年第9期25卷 1047-1050页

作者： jiN Yi CHE Yun-Xia ZHENG ji-min Department of Chemistry Nankai University Tianjin 300071 China

A novel nickel（Ⅱ） complex with L-histidine has been synthesized and solved by single-crystal X-ray diffraction analysis at physiological pH. The title complex （C7H16NiN4O6S, Mr = 343.01） crystallizes in monoclinic, space group P21 with a = 7.2194（7）, b = 7.5968（7）, c = 12.2797（11） A, β = 93.3110（10）°, V = 672.35（11） A^3, Z = 2, Dc= 1.694 g/cm^3, F（000） = 356, μ（MoKα） = 1.626 mm^-1, T = 293（2） K, the final R = 0.0184 and wR = 0.0426 for 2207 observed reflections with 1 〉 2σ（I）. The complex provides insights into a possible structural arrangement between nickel （Ⅱ） and L-histidine which may be physiologically important and abundantly present in biological systems.

关键词： crystal structure synthesis L-histidine nickel physiological pH

mRNA stability in the nucleus

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2014年第5期15卷 444-454页

作者： Han LIU min LUO ji-kai wen Institute of Cancer Stem Cell Dalian Medical University Chongqing Institute of Tuberculosis Prevention and Treatment Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms College of Life SciencesSouth China Agricultural University

Eukaryotic gene expression is controlled by different levels of biological events, such as transcription factors regulating the timing and strength of transcripts production, alteration of transcription rate by RNA processing, and mRNA stability during RNA processing and translation. RNAs, especially mRNAs, are relatively vulnerable molecules in living cells for ribonucleases （RNases）. The maintenance of quality and quantity of transcripts is a key issue for many biological processes. Extensive studies draw the conclusion that the stability of RNAs is dedicated-regulated, occurring co- and post-transcriptionally, and translation-coupled as well, either in the nucleus or cytoplasm. Recently, RNA stability in the nucleus has aroused much research interest, especially the stability of newly-made transcripts. In this article, we summarize recent progresses on mRNA stability in the nucleus, especially focusing on quality control of newly-made RNA by RNA polymerase Ⅱ in eukaryotes.

关键词： mRNA stability Nuclear mRNA retention Quality control mRNA degradation

Reducing the Upper Bound Delay by Optimizing Bank-to-Core Mapping

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Journal of Computer Science & Technology 2016年第6期31卷 1179-1193页

作者： ji-Zan Zhang Zhi-min Gu ming-Quan Zhang School of Computer Science and Technology Beijing Institute of Technology Beijing 100081 China School of Mathematics and Information Ludong University Yantai 264025 China

Nowadays, inter-task interferences are the main difficulty in analyzing the timing behavior of multicores. The timing predictable embedded multicore architecture MERASA, which allows safe worst-case execution time （WCET） estimations, has emerged as an attractive solution. In the architecture, WCET can be estimated by the upper bound delay （UBD） which can be bounded by the interference-aware bus arbiter （IABA） and the dynamic cache partitioning such as columnization or bankization. However, this architecture faces a dilemma between decreasing UBD and efficient shared cache utilization. To obtain tighter WCET estimation, we propose a novel approach that reduces UBD by optimizing bank-to-core mapping on the multicore system with IABA and the two-level partitioned cache. For this, we first present a new UBD computation model based on the analysis of inter-task interference delay, and then put forward the core-sequence optimization method of bank-to-core mapping and the optimizing algorithms with the minimum UBD. Experimental results demonstrate that our approach can reduce WCET from 4% to 37%.

关键词： multicore hard real-time task bank-to-core mapping upper bound delay optimization

Role of carbon in modifying solidification and microstructure of a Ni?based superalloy with high Al and Ti contents

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Journal of Iron and Steel Research International 2021年第1期28卷 98-110页

作者： Guang‑di Zhao Xi‑min Zang wen‑ru Sun School of Materials and Metallurgy University of Science and Technology LiaoningAnshan 114051LiaoningChina Institute of Metal Research Chinese Academy of SciencesShenyang 110016LiaoningChina

The effect of carbon ranging from 0.014 to 0.071 wt.%on the solidification and microstructure of a Ni-based superalloy with high Al and Ti contents was *** results show that the increase in carbon addition significantly increases the size and volume fraction of MC carbides and promotes the change of their morphology from blocky to elongated ***,the carbon addition obviously decreases the size and volume fraction of eutectic(γ+γ′)and reducesηphase and borides *** change in carbide characteristics is mainly because of the increasing carbide-forming element and carbides precipitation temperature with the increase in carbon which favors the growth of them along the interdendritic liquid *** carbides are formed at an earlier solidification stage than the eutectic(γ+γ′).The increased carbide formation consumes more Ti,which delays and reduces the eutectic(γ+γ′)*** delay of eutectic(γ+γ′)precipitation leads to a deeper undercooling,which significantly decreases the critical Ti concentration for its ***,in turn,lowers Ti/Al ratio in residual liquids ahead of the eutectic(γ+γ′)and hence reducesηformation subsequently.B and Zr are slightly enriched in the carbides,which are considered during discussing how carbon influences the eutectic(γ+γ′)precipitation.

关键词： Carbon Ni-based superalloy Solidification Segregation Eutectic(γ+γ′) MC carbide

HYDRODYNAMIC INTERACTION BETWEEN FLNG VESSEL AND LNG CARRIER IN SIDE BY SIDE CONFIGURATION

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Journal of Hydrodynamics 2012年第5期24卷 648-657页

作者： ZHAO wen-hua YANG jian-min HU Zhi-qiang State Key Laboratory of Ocean Engineering Shanghai Jiao Tong UniversityShanghai 200240China

The Floating Liquefied Natural Gas （FLNG） is a new type of floating platform for the exploitation of stranded offshore oil/gas fields. The side by side configuration for the FLNG vessel and the LNG carrier arranged in parallel is one of the possible choices for the LNG offloading. During the offloading operations, the multiple floating bodies would have very complex responses due to their hydrodynamic interactions. In this study, numerical simulations of multiple floating bodies in close proximity in the side by side offloading configuration are carried out with the time domain coupled analysis code SIMO. Hydrodynamic interactions between the floating bodies and the mechanical coupling effects between the floating bodies and their connection systems are included in the coupled analysis model. To clarify the hydrodynamic effects of the two vessels, numerical simulations under the same environmental condition are also conducted without considering the hydrodynamic interactions, for comparison. It is shown that the hydrodynamic interactions play an important role in the low frequency motion responses of the two vessels, but have little effect on the wave frequency motion responses. In addition, the comparison results also show that the hydrodynamic interactions can affect the loads on the connection systems.

关键词： Floating Liquefied Natural Gas (FLNG) hydrodynamic interactions side by side operation relative motions

Effect of carbon addition on creep behavior of cast TiAl alloy with hard-oriented directional lamellar microstructure

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Journal of Iron and Steel Research International 2020年第11期27卷 1347-1356页

作者： Xi-wen Zhang Yu-ling Tang wen-juan Wan Chun-lei Zhu ji Zhang Beijing Key Laboratory of Advanced High Temperature Materials China Iron and Steel Research Institute GroupBeijing 100081China National Center for Electron Microscopy in Beijing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

Two TiAl alloys,Ti-47.5Al-3.7(Cr,V,Zr)and Ti-47.5Al-3.7(Cr,V,Zr)-0.1C(at.%),were prepared by cold crucible levitation melting to couple the hard-oriented directional lamellar microstructure with carbon microalloying *** creep behavior and mechanism for the improvement in creep properties by carbon addition were investigated by mechanical tests and electron microscopy *** results show that obvious improvements on the creep properties at 760°C and 276 MPa are achieved by 0.1 at.%C addition into TiAl alloy with directional lamellar microstructure,which promotes the creep strain and minimum creep rate decreasing with a large *** minimum creep rate is reduced from 4.37×10^(-8) to 3.97×10^(-9) s^(-1),and the duration entering into creep acceleration is prolonged for more than 10 *** mechanism for creep property improvement by 0.1%C addition is attributed to two *** first one is that Ti_(2) AlC is found to be strong obstacles of 1/2[110]dislocations when moving across the lamellar interface in the carbon containing *** other one is that the in terfacial dislocatio ns are effectively impeded and the release process is hindered by dynamic precipitation of Ti_(3) AlC,which is proposed to be the special mechanism for creep resistance improvement of this hard-oriented directional lamellar microstructure.

关键词： Cast titanium aluminide Lamellar microstructure Creep behavior Carbon addition Dynamic precipitation