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Control of Macrosegregation Behavior by Applying Final Electromagnetic Stirring for Continuously Cast High Carbon Steel Billet

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Journal of Iron and Steel Research International 2013年第11期20卷 13-20页

作者： xiao Chao ZHANG Jiong-ming luo Yan-zhao WEI xiao-dong WU Lian WANG Shun-xi State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

Solidification behavior of continuously cast high carbon steel billets was investigated with an objective of producing high quality billets by determining the optimum final electromagnetic stirring （F-EMS） parameters. Char- acteristics of centerline segregation were analyzed for lots of billet samples collected from the plant through obtaining the carbon concentrations of drill chips, which were correlated with the operating parameters of the caster and stir- rers, but a problem occurred that segregation control results of trial billets with the same casting and stirring param- eters often have drastic fluctuations. An attempt was made to find out the induced reasons of this problem by meas uring the electromagnetic torque, analyzing the secondary dendrite arm spacing （SDAS） and the corresponding cool- ing rate of the typical specimens, and observing the longitudinal profile of etched billet samples. Then a simple dy- namic secondary cooling model was developed based on the solidified shell thickness control mode, by which the maximum carbon segregation index was reduced effectively, and thus the segregation fluctuation problem was basi- cally solved. Finally, the most favourable stirring parameters were determined as the casting speed of 1.65 m/rain, the liquid core thickness of 40 mm, stirring current of 360 A and frequency of 12 Hz.

关键词： F-EMS carbon segregation index SDAS cooling rate stirring parameter

The nucleocapsid of vesicular stomatitis virus

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Science China(Life Sciences) 2012年第4期55卷 291-300页

作者： luo ming Department of Microbiology the University of Alabama at Birmingham Birmingham 35294 USA

The nucleocapsid of vesicular stomatitis virus serves as the genomic template for transcription and replication. The viral genomic RNA is sequestered in the nucleocapsid in every step of the virus replication cycle. The structure of the nucleocapsid and the entire virion revealed how the viral genomic RNA is encapsidated and packaged in the virus. A unique mechanism for viral RNA synthesis is derived from the structure of the nuleocapsid and its interactions with the viral RNA-dependent RNA polymerase.

关键词： RNA cavity cross-molecular interactions RNA access phosphoprotein binding to the nucleocapsid bullet-shaped vi-rion

Lightweight,Strong and High Heat-Resistant Poly(lactide acid)Foams via Microcellular Injection Molding with Self-Assembly Nucleating Agent

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Chinese Journal of Polymer Science 2024年第6期42卷 739-750页

作者： xiao-Hu Bing Wen-Yu Ma ming-Hui Wu Peng Gao xiao Zhou Hai-Bin luo Long Wang Wen-Ge Zheng School of materials Science and Engineering Shanghai UniversityShanghai200444China Ningbo Key Lab of Polymer Materials Ningbo Institute of Material Technology and EngineeringChinese Academy of SciencesNingbo315201China University of Chinese Academy of Sciences Beijing100049China

Poly(lactide acid)(PLA)foams have shown considerable promise as eco-friendly alternatives to nondegradable plastic foams,such as polystyrene(PS)***,PLA foam typically suffers from low heat-resistance and poor cellular structure stemming from its inherent slow crystallization rate and low melt *** this study,a high-performance PLA foam with well-defined cell morphology,exceptional strength and enhanced heat-resistance was successfully fabricated via a core-back microcellular injection molding(MIM)*** scanning calorimetry(DSC)results revealed that the added hydrazine-based nucleating agent(HNA)significantly increased the crystallization temperature and accelerated the crystallization process of ***,the addition of a 1.5 wt%of HNA led to a significant reduction in PLA’s cell size,from 43.5µm to 2.87µm,and a remarkable increase in cell density,from 1.08×10^(7)cells/cm^(3)to 2.15×10^(10)cells/cm^(3).This enhancement resulted in a final crystallinity of approximately 55.7%for the PLA blend foam,a marked improvement compared to the pure PLA ***,at 1.5 wt%HNA concentration,the tensile strength and tensile toughness of PLA blend foams demonstrated remarkable improvements of 136%and 463%,***,the Vicat softening temperature of PLA blend foam increased significantly to 134.8°C,whereas the pure PLA foam exhibited only about 59.7℃.These findings underscore the potential for the preparation of lightweight injection-molded PLA foam with enhanced toughness and heat-resistance,which offers a viable approach for the production of high-performance PLA foams suitable for large-scale applications.

关键词： Poly(lactide acid) Nucleating agent Microcellular injection molding Heat-resistance Toughness

SIMULATION OF OIL-WATER TWO PHASE FLOW AND SEPARATION BEHAVIORS IN COMBINED T JUNCTIONS

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Journal of Hydrodynamics 2012年第6期24卷 848-857页

作者： CHEN Jian-lei HE Li-min luo xiao-ming BAI Hai-tao WEI Yan-hai College of Pipeline and Civil Engineering China University of Petroleum(East China)

The combined T junctions used for the oil-water separation have the advantages of compactness in structure, consistency in effects and economy in cost. The mixture k- ε turbulence model and the Eulerian multi-fluid model are used to simulate the flow and phase distribution in the combined T junctions. The effects of structural parameters such as the branched pipe interval and height on the flow distribution and the separation behaviors are studied. The results show that the combined T junctions under fixed inlet and outlet boundary conditions form a single hydraulic equilibrium system in which the fluid energy distributes freely till a balance is achieved. The split-flow promotes the separation of the immiscible oil and the water. The separation efficiency increases with the increase of the branched pipe interval and changes slightly with the increase of the branched pipe height. The structural change of the combined T junctions may change the flow direction in the branched pipes. Simulation results can provide some guidance for the design of the combined T junctions as one kind of oil-water separator.

关键词： T junction oil-water separation CFD phase distribution

Recent progress in synthesis of composite powders and their applications in low-carbon refractories

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Journal of Iron and Steel Research International 2022年第7期29卷 1041-1051页

作者： Ji-yuan luo Xin-ming Ren xiao-chuan Chong Dong-hai Ding Bei-yue Ma Guo-qing xiao Jing-kun Yu College of Materials Science and Engineering Xi’an University of Architecture and TechnologyXi’an 710055ShaanxiChina School of Metallurgy Northeastern UniversityShenyang 110819LiaoningChina

The development of low-carbon refractories is of great significance,but it is limited by the deteriorated properties that resulted from the decreased graphite *** composite powders has proved to be effective in improving the properties of low-carbon *** recent progress in the synthesis of composite powders including modified graphite,nanocarbon-containing composite powders,oxide/non-oxide and non-oxide composite powders and their applications in low-carbon refractories were reviewed,and the future development of composite powder technology was prospected.

关键词： Composite powder Modified graphite Nanocarbon-containing composite powder Oxide/non-oxide Non-oxide Low-carbon refractory

An Empirical Formula of Atomic K-Shell Ionization Cross Sections by Electron Impact

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Chinese Physics Letters 2001年第8期18卷 1053-1055页

作者： TANG Chang-Huan AN Zhu FAN xiao-Qiang luo Zheng-ming Laser Fusion Research Center CAEPMianyang 621900 Institute of Nuclear Science and Technology Sichuan UniversityKey Laboratory for Radiation Physics and Technology of Education Ministry of ChinaChengdu 610064 Institute of Nuclear Physics and Chemistry CAEPMianyang 621900

An empirical formula is proposed to describe the K-shell ionization cross sections by electron impact over a wide range of atomic numbers and overvoltages U(the ratio between the electron incident energy and the binding energy of the electrons in the K-shell).The study is based on the analysis of existing experimental data of K-shell ionization cross *** expression shows the results in good agreement with the data for Z<6 atoms as well as for 6≤Z≤79.

关键词： Electron ionization incident

Biomass-derived dynamic covalent epoxy thermoset with robust mechanical properties and facile malleability

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Chinese Chemical Letters 2022年第6期33卷 3245-3248页

作者： xiao-Min Ding Li Chen Xi luo Feng-ming He Yan-Fang xiao Yu-Zhong Wang The Collaborative Innovation Center for Eco-Friendly and Fire-Safety Polymeric Materials(MoE) National Engineering Laboratory of Eco-Friendly Polymeric Materials(Sichuan)State Key Laboratory of Polymer Materials EngineeringCollege of ChemistrySichuan UniversityChengdu 610064China

Biomass-derived dynamic covalent thermoset has been considered as a promising solution to the high dependence on fossil resources and the difficulty in recyclability after curing of conventional bisphenol A epoxy ***,the design and preparation of a dynamic covalent biobased epoxy thermoset with both comparable thermal and mechanical performances to bisphenol A epoxy resins and reprocessibility remains a significant ***,based on imine chemistry,a novel Schiff base-containing dynamic covalent epoxy thermoset was facilely fabricated from biobased protocatechualdehyde and synthetic siloxane *** to the more reactive epoxides in the epoxy monomer than in bisphenol A epoxy oligomer,the thermoset exhibited a high cross-linking density,resulting in high thermal stability and glass transition *** rigid aromatic Schiff base moieties endowed the thermoset with excellent mechanical properties:Thanks to the plasticization of the flexible siloxane,the thermoset displayed high impact ***,owing to the high segmental mobility,the fast exchange of imine bonds was guaranteed;and the thermoset was able to be recycled through *** these features,this work provided great potential for designing and preparing sustainable substitutes for bisphenol A epoxy resins in the high-performance applications.

关键词： Epoxy resin Dynamic covalent thermoset Protocatechualdehyde Imine chemistry High-performance

Nonlinear Absorption and Dispersion Response in Optically Dense Media Driven by a Single-Mode Laser

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Communications in Theoretical Physics 2006年第1X期46卷 130-134页

作者： LI Jia-Hua LIU Ji-Bing XIE xiao-Tao luo Jin-ming Department of Physics Huazhong University of Science and Technology Wuhan 430074 China

Taking the density-dependent near dipole-dipole （NDD） interaction into consideration, we theoretically investigate the response of nonlinear absorption and dispersion in optically dense media of three-level atoms driven by a single-mode probe laser. The influence of the NDD effects on the absorption and dispersion spectra of the probe field is predicted via numerical calculations. It is shown that the NDD effects reduce gradually to transient absorption and amplification with the increase of the strengths of the NDD interaction, but do not change the steady-state behavior. Due to the presence of the NDD effects, steady-state absorption spectra exhibit asymmetric double-peak structure and overall shifts when a continuous-wave （cw） probe field is applied. However, frequency dispersion spectra are insensitive to them near the zero detuning.

关键词： absorption spectra dispersion spectra near dipole-dipole interactions

Effect of Artemisia annua Extract on Treating Active Rheumatoid Arthritis:A Randomized Controlled Trial

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Chinese Journal of Integrative Medicine 2017年第7期23卷 496-503页

作者： YANG Min GUO ming-yang luo Yong YUN ming-dong YAN Jiao LIU Tao xiao Chang-hong Department of Traditional Chinese Medicine Rheumatology Center of Integrated Traditional and Western MedicineGeneral Hospital of Chengdu Military Area Command PLA Department of Internal Medicine School of Traditional Chinese MedicineSouthern Medical University

Objective：To investigate the effect and safety of the complementary use of the extract of Artemisia annua L.（EAA） on treating active rheumatoid arthritis（RA）. Methods：A randomized controlled clinical trial was performed. All the 159 participates with active RA were randomly assigned to the control group（80 cases） and EAA group（79 cases） using concealed random allocation method. In the control group, patients were medicated with leflunomide and methotrexate for 48 weeks; and patients in the EAA group were administrated with leflunomide, methotrexate plus EAA（30 g/d）. At the time points of 0, 12, 24 and 48 weeks, the clinical outcome measures, including objective pain score, tenderness score, number of painful joints, number of swollen joints, health assessment questionnaire（HAQ） score for quality of life, levels of serum rheumatoid factor（RF）, anti-cyclic citrullinated protein antibodies（CCP-Ab）, erythrocyte sedimentation rate（ESR）, C reactive protein（CRP）, visual analogue score for pain（VAS）, and the overall efficacy were detected and recorded. Results：The objective pain score, number of painful joints and ESR at 12 weeks, tenderness score and HAQ at 24 weeks, and the tenderness score, number of painfull joints, number of swollen joints, HAQ, CRP, RF and CCP-Ab at 48 weeks were significantly improved in the EAA group compared with the control group（P〈0.01 or P〈0.05）. At 24 and 48 weeks, the overall efficacy of the EAA group was significantly higher than the control group（P〈0.01）. There were significantly higher withdrawal rate of corticosteroids within 12 weeks post-treatment and lower incidence rate of adverse effects in the EAA group compared with the control group（P〈0.01 or P〈0.05）. Conclusion：EAA plus methotrexate and leflunomide were more effective and safer than the routine use of methotrexate and leflunomide in the treatment of active RA.

关键词： rheumatoid arthritis leflunomide methotrexate Artemisia annua Chinese medicine