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Effects of trace calcium and strontium on microstructure and properties of Cu-Cr alloys

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Journal of Materials Science & Technology 2022年第17期112卷 11-23页

作者： Muzhi Ma Zhu Xiao Xiangpeng Meng Zhou Li Shen gong jie Dai Hongyun Jiang Yanbin Jiang Qian Lei Haigen wei School of Materials Science and Engineering Central South UniversityChangsha 410083China Key Laboratory of Non-ferrous Metal Materials Science and Engineering Ministry of EducationChangsha 410083China Ningbo Boway Alloy Material Co. Ltd.Ningbo 315135China State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China Zhejiang Tianning Alloy Material Co. Ltd.Jinhua 321002China Faculty of Materials Metallurgy and Chemistry Jiangxi University of Science and TechnologyGanzhou 341000China

Cu-0.57Cr-0.01Ca and Cu-0.58Cr-0.01Sr(wt.%)alloys were fabricated and processed by thermo-mechanical *** mechanical and electrical properties and microstructure were investigated in detail and compared with those of a Cu-0.57Cr(wt.%)*** results showed that the softening resistance of the Cu-Cr alloy was significantly improved by the additions of Ca and Sr *** with the Cu-Cr alloy,the deformation microstructure of the Cu-Cr-Ca and Cu-Cr-Sr alloys was more difficult to recrystallize at elevated temperatures,and the Cr precipitates in the Cu-Cr-Ca and Cu-Cr-Sr alloys were smaller in size and had an FCC structure at any given aging *** high strengths of the Cu-Cr-Ca and Cu-Cr-Sr alloys were mainly attributed to the dislocation strengthening provided by high-density dislocations and the precipitate strengthening provided by fine Cr ***-principles calculation showed that the segregations of Ca and Sr atoms at interface between Cr precipitates and copper matrix were favorable in *** segregation effectively hindered the growth of Cr precipitates and significantly enhanced the pinning effect on the motion of dislocations and subgrain boundaries,eventually leading to the improvement in the softening resistance of the Cu-Cr alloy.

关键词： Cu-Cr alloy Softening resistance Microstructure Strengthening Segregation

Numerical Study of New-Type Receiver with Axially-Hollow Spiral Deflector for Parabolic Trough Direct-Steam-Generation Loop of Concentrating Solar Power System

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Journal of Thermal Science 2023年第2期32卷 597-610页

作者： SHI Yaolu SUN jie wei Jinjia School of Chemical Engineering and Technology Xi'an Jiaotong UniversityXi'an 710049China Adv Energy Sci&Technol Guangdong Lab Foshan Xianhu LabXianhu Hydrogen ValleyFoshan 528200China

The thermal stress-induced deformation issue of receiver is crucial to the performance and reliability of a parabolic-trough(PT) concentrating solar power(CSP) system with the promising direct steam generation(DSG) *** objective of the present study is to propose a new-type receiver with axially-hollow spiral deflector and optimize the geometric structure to solve the above *** this end,optical-flow-thermal multi-physics coupling models have been established for the preheating,boiling and superheating sections of a typical PT-DSG *** simulation results show that our proposed new-type receiver demonstrates outstanding comprehensive *** can minimize the circumferential temperature difference through the spiral deflector while lower the flow resistance cost through the axially hollow structure at the same *** quantitatively evaluated by the temperature uniformity improvement(ε_(ΔT)) and the performance evaluation criteria(PEC),different designs are achieved based on different optimal *** ε_(ΔT)is of primary importance,the optimal design with torsional ratio of 1 is achieved,with ε_(ΔT)=25.4%,25.7%,41.5% and PEC=0.486,0.878,0.596corresponding to preheating,boiling,superheating sections,*** PEC is of primary importance,the optimal design with torsional ratio of 6-6.5 is achieved,with PEC=0.950,2.070,0.993 and ε_(ΔT)=18.2%,13.3 %,19.4% corresponding to preheating,boiling,superheating sections,respectively.

关键词： concentrating solar power parabolic though collector direct steam generation performance evaluation criteria axially-hollow spiral deflector

Terpenoid Indole Alkaloids Biosynthesis and Metabolic Engineering in Catharanthus roseus

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Journal of Integrative Plant Biology 2007年第7期49卷 961-974页

作者： Dong-Hui Liu Hong-Bin Jin Yu-Hui Chen Li-jie Cui wei-wei Ren Yi-Fu gong Ke-Xuan Tang Shanghai Key Laboratory of Agrobiotechnology Plant Biotechnology Research Center Fudan-Shanghai Jiaotong University ( SJTU)-Nottingham Plant Biotechnology R & D Center School of Agriculture and Biology Shanghai Jiaotong University Shanghai 200030 China Department of Biochemistry and Molecular Biology Shenyang Medical College Shenyang 110034 China Faculty of Life Sciences and Biotechnology Ningbo University Ningbo 315211 China State Key Laboratory of Genetic Engineering School of Life Sciences Fudan-SJTU-Nottingham Plant Biotechnology R & D Center Morgan-Tan International Center for Life Sciences Fudan University Shanghai 200433 China

Catharanthus roseus L. （Madagascar periwinkle） biosynthesizes a diverse array of secondary metabolites including anticancer dimeric alkaloids （vinblastine and vincristine） and antihypertensive alkaloids （ajmalicine and serpentine）. The multi-step terpenoid indole alkaloids （TIAs） biosynthetic pathway in C. roseus is complex and is under strict molecular regulation. Many enzymes and genes involved in the TIAs biosynthesis have been studied in recent decades. Moreover, some regulatory proteins were found recently to control the production of TIAs in C. roseus. Based on mastering the rough scheme of the pathway and cloning the related genes, metabolic engineering of TIAs biosynthesis has been studied in C. roseus aiming at increasing the desired secondary metabolites in the past few years. The present article summarizes recent advances in isolation and characterization of TIAs biosynthesis genes and transcriptional regulators involved in the second metabolic control in C. roseus. Metabolic engineering applications in TIAs pathway via overexpression of these genes and regulators in C. roseus are also discussed.

关键词： biosynthesis pathway Catharanthus roseus metabolic engineering terpenoid indole alkaloids.

A Novel Integrated Method for Large-Scale Detection, Identification, and Quantification of Widely Targeted Metabolites： Application in the Study of Rice Metabolomics

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Molecular Plant 2013年第6期6卷 1769-1780页

作者： wei Chen Liang gong Zilong GUO Wensheng Wang Hongyan Zhang Xianqing Liu SibinYu Lizhong Xiong jie Luo National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan) Huazhong Agricultural University Wuhan430070 China Key Laboratory of Horticultural Plant Biology (Ministry of Education) Huazhong Agricultural University Wuhan 430070 China College of Life Science and Technology Huazhong Agricultural University Wuhan 430070 China

Liquid chromatography-mass spectrometry （LC-MS）-based metabolomics has been facilitated by the con- struction of MSz spectral tag （MS2T） library from the total scan ESI MS/MS data, and the development of widely targeted metabolomics method using MS/MS data gathered from authentic standards. In this report, a novel strategy called step- wise multiple ion monitoring-enhanced product ions （stepwise MIM-EPI） was developed to construct the MS2T library, in which stepwise MIM was used as survey scans to trigger the acquisition of EPI. A total number of 698 （almost） non- redundant metabolites with MS2 spectra were obtained, of which 135 metabolites were identified/annotated. Integrating the data gathered from our MS2T library and other available multiple reaction monitoring （MRM） information, a widely targeted metabolomics method was developed to quantify 277 metabolites, including some phytohormones. Evaluation of the dehydration responses and natural variations of these metabolites in rice leaf not only suggested the coordinated regulation of abscisic acid （ABA） with metabolites such as serotonin derivative（s）, polyamine conjugates under drought stress, but also revealed some C-glycosylated flavones as the potential markers for the discrimination of indica and japonica rice subspecies. The new MS2T library construction and widely targeted metabolomics strategy could be used as a tool for rice functional genomics.

关键词： MS2T library widely targeted metabolic profiling flavonoid rice.

Modeling Seasonal Variations of Subsurface Chlorophyll Maximum in South China Sea

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Journal of Ocean University of China 2014年第4期13卷 561-571页

作者： gong Xiang SHI jie GAO Huiwang Key Laboratory of Marine Environment and Ecology Ocean University of China

In the South China Sea(SCS), the subsurface chlorophyll maximum(SCM) is frequently observed while the mechanisms of SCM occurrence have not been well understood. In this study, a 1-D physical-biochemical coupled model was used to study the seasonal variations of vertical profiles of chlorophyll-a(Chl-a) in the SCS. Three parameters(i.e., SCM layer(SCML) depth, thickness, and intensity) were defined to characterize the vertical distribution of Chl-a in SCML and were obtained by fitting the vertical profile of Chl-a in the subsurface layer using a Gaussian function. The seasonal variations of SCMs are reproduced reasonably well compared to the observations. The annual averages of SCML depth, thickness, and intensity are 75 ± 10 m, 31 ± 6.7 m, and 0.37 ± 0.11 mg m-3, respectively. A thick, close to surface SCML together with a higher intensity occurs during the northeastern monsoon. Both the SCML thickness and intensity are sensitive to the changes of surface wind speed in winter and summer, but the surface wind speed exerts a minor influence on the SCML depth; for example, double strengthening of the southwestern monsoon in summer can lead to the thickening of SCML by 46%, the intensity decreasing by 30%, and the shoaling by 6%. This is because part of nutrients are pumped from the upper nutricline to the surface mixed layer by strong vertical mixing. Increasing initial nutrient concentrations by two times will increase the intensity of SCML by over 80% in winter and spring. The sensitivity analysis indicates that light attenuation is critical to the three parameters of SCM. Decreasing background light attenuation by 20% extends the euphotic zone, makes SCML deeper(~20%) and thicker(12% – 41%), and increases the intensity by over 16%. Overall, the depth of SCML is mainly controlled by light attenuation, and the SCML thickness and intensity are closely associated with wind and initial nitrate concentration in the SCS.

关键词： South China Sea subsurface chlorophyll maximum seasonal variation numerical modeling

An improved imaging algorithm for spaceborne MAPs sliding spotlight SAR with high-resolution wide-swath capability

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Chinese Journal of Aeronautics 2015年第4期28卷 1178-1188页

作者： Kuang Hui Chen jie Yang wei Liu wei School of Electronic and Information Engineering Beihang University Electronic and Electrical Engineering Department University of Sheffield

Conventional synthetic aperture radar（SAR） systems cannot achieve both highresolution and wide-swath imaging *** problem can be mitigated by employing multiple-azimuth-phases（MAPs） technology for spaceborne sliding spotlight SAR ***, traditional imaging algorithms have met challenges to process the data accurately, due to range model error, MAPs data reconstruction problem, high-order cross-coupling phase error and variation of Doppler parameters along the azimuth ***, an improved imaging algorithm is proposed for solving the above ***, a modified hyperbolic range equation（MHRE） is proposed by introducing a cubic term into the traditional hyperbolic range equation（THRE）.And two curved orbit correction methods are derived based on the proposed range ***, a MAPs sliding spotlight data reconstruction method is introduced, which solves the spectral aliasing problem by a de-rotation ***, high-order cross-coupling phases and variation of Doppler parameters are analyzed and the corresponding compensation methods are *** results for point-target scene are provided to verify the effectiveness of the proposed algorithm.

关键词： High resolution Imaging Multiple-azimuth-phasesSliding spotlight Synthetic aperture radarWide swath

Spin-Dependent Electron Properties of a Triple-Terminal Quantum Dot Structure

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Communications in Theoretical Physics 2009年第12期52卷 1117-1124页

作者： HAN Yu gong wei-Jiang wei Guo-Zhu Department of Physics Liaoning University Shenyang 110036 China College of Sciences Northeastern University Shenyang 110004 China International Center for Material Physics Acadmia Sinica Shenyang 110015 China

Electron transport properties of a triple-terminal Aharonov-Bohm interferometer are theoretically *** applying a Rashba spin-orbit coupling to a quantum dot locally, we find that remarkable spin polarization comesabout in the electron transport process with tuning the structure parameters, i.e., the magnetic flux or quantum dotlevels. When the quantum dot levels are aligned with the Fermi level, there only appear spin polarization in thisstructure by the presence of an appropriate magnetic flux. However, in absence of magnetic flux spin polarization andspin separation can be simultaneously realized with the adjustment of quantum dot levels, namely, an incident electronfrom one terminal can select a specific terminal to depart from the quantum dots according to its spin state.

关键词： quantum dot electron transport Rashba interaction

Hierarchical molybdenum disulfide nanosheet arrays stemmed from nickel-cobalt layered double hydroxide/carbon cloth for highly-efficient hydrogen evolution reaction

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Journal of Energy Chemistry 2021年第6期30卷 587-592,I0014页

作者： Yuxuan wei Yanlong Lv Beidou Guo Jianru gong Chinese Academy of Sciences(CAS)Center for Excellence in Nanoscience CAS Key Laboratory for Nanosystem and Hierarchical FabricationNational Center for Nanoscience and TechnologyBeijing 100190China University of CAS Beijing 100049China

The hierarchical structure of molybdenum disulfide(MoS2)nanosheet arrays stemmed from nickelcobalt layered double hydroxide(NiCo-LDH)/carbon cloth was prepared by growing the MoS_(2) nanosheet arrays onto the NiCo-LDH template which was pre-deposited onto the carbon cloth *** this electrode configuration,carbon cloth is the three dimensional and conductive skeleton;NiCo-LDH nanosheets,as the template,ensure the oriented growth of MoS2 nanosheet ***,more MoS_(2) active sites are exposed and the catalyst exhibits good hydrogen evolution reaction activity.

关键词： Hydrogen evolution reaction catalysts Hierarchical structure Molybdenum disulfide Nickel-cobalt layered double hydroxide

In Situ Corrosion Monitoring of Mild Steel in a Simulated Tidal Zone without Marine Fouling Attachment by Electrochemical Impedance Spectroscopy

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Journal of Materials Science & Technology 2014年第10期30卷 1043-1050页

作者： Xin Mu jie wei Junhua Dong wei Ke State Key Laboratory for Corrosion and Protection Institute of Metal ResearchChinese Academy of Sciences

The corrosion behaviors of the isolated short and vertical long scale Q235B steel in a simulated tidal zone were studied by electrochemical impedance spectroscopy （EIS） monitoring and corrosion weight loss calculation in an experimental indoor simulating trough. The results show that the corrosion rate of the isolated short scale Q235B steel in the tidal zone acquired by the EIS agrees with the corrosion weight loss result. The corrosion rates of the short scale steel are in the order of middle tidal zone 〉 the central zone between the middle tidal zone and low tidal zone 〉 high tidal zone 〉 low tidal zone. The fastest corrosion rate in the middle tidal zone is attributed to the longest wet time in a tidal cycle. According to the comparison of corrosion weight loss between the vertical long scale and isolated short scale specimens, the corrosion rate of vertical long scale specimens of Q235B steel is lower than that of the isolated short scale specimens in the tidal zone, but the result is contrary in the immersion zone.

关键词： Laboratory simulation Tidal corrosion Mild steel Electrochemical impedance spectroscopy weight loss