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Development of a MWDC prototype of the CSR external-target experiment

NUCLEAR SCIENCE AND TECHNIQUES 2024年第10期35卷 1-14页

作者： He, Zhou-Bo Qin, Zhi Ma, Peng yang, He-Run Wei, Xiang-Lun Lu, Chen-Gui Wen, Xiang-Jie Zhang, Xiu-Ling Chen, Tao Li, Zhi-Jie yang, yuan-sheng Zhan, Mei-Qiang Liu, Can-Wen Li, Meng Qiu, Tian-Li Gong, Yi-Wei Huang, Xin-Jie Yin, Xiao-Hao He, Zhi-Xuan Zhang, Jun-Wei Zou, Hai-Chuan Fu, sheng-Wei Guo, Dong Yan, Jun-Wei Cao, Zhe Deng, Zhi Kong, Jie Xiao, Zhi-Gang Hu, Rong-Jiang Duan, Li-Min Chinese Acad Sci Inst Modern Phys Lanzhou 730000 Peoples R China Univ Chinese Acad Sci Sch Nucl Sci & Technol Beijing 100049 Peoples R China Tsinghua Univ Dept Phys Beijing 100084 Peoples R China Univ Sci & Technol China Hefei 230026 Peoples R China Sichuan Univ Inst Nucl Sci & Technol Key Lab Radiat Phys & Technol Minist Educ Chengdu 610064 Peoples R China Lanzhou Univ Sch Nucl Sci & Technol Lanzhou 730000 Peoples R China North China Univ Water Resources & Elect Power Zhengzhou 450000 Peoples R China

The cooling storage ring (CSR) external-target experiment (CEE) is a spectrometer used in construction to study the properties of nuclear matter in high-baryon density regions at the Heavy-Ion Research Facility in Lanzhou (HIRFL). This study presents the design, simulation, manufacturing, and testing of a half-size prototype of a multi-wire drift chamber (MWDC) for the CEE. First, the performance of the MWDC connected to homemade electronics was simulated. The results demonstrated that an energy resolution of 18.5% % for 5.9-keV X-rays and a position resolution of 194 mu m for protons can be achieved by the current design. Because the size of the largest MWDC reached 176 cm x 314 cm, a set of 98 cm x 98 cm prototypes was built using the new techniques. The positioning accuracy of the anode wires in this prototype is better than 20 mu m. After optimization, using commercially available electronics, the prototype can achieved an energy resolution of 19.7% % for a Fe-55 X-ray source. The CEE-MWDC detector and electronics were simultaneously tested. An energy resolution of 22% % was achieved for the Fe-55 source; the track residuals were approximately 330 mu m for the cosmic rays. The results demonstrate that the current design and techniques meet the requirements of the CEE-MWDC array.

关键词： CEE MWDC Garfield plus plus Fe-55 source Position resolution DRIFT CHAMBER HIRFL-CSR

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大豆田生境红火蚁工蚁的活动性程度评价

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环境昆虫学报 2024年第2期46卷 354-362,I0001-I0002页

作者：金涛钟浩郝铮马光昌杨升院龚治中国热带农业科学院环境与植物保护研究所农业农村部热带作物有害生物综合治理重点实验室海南省热带农业有害生物监测与控制重点实验室海口571101

应用刻度图示法观察记录了海口市大豆田生境红火蚁Solenopsis invicta Buren工蚁的活动性水平,并对蚁巢大小及活动时间与工蚁数量、爬升高度和恢复平静时间等指标值进行了通径分析。对41个蚁巢观察结果表明,除了1个蚁巢外,蚁巢惊扰后60 ... 详细信息

应用刻度图示法观察记录了海口市大豆田生境红火蚁Solenopsis invicta Buren工蚁的活动性水平,并对蚁巢大小及活动时间与工蚁数量、爬升高度和恢复平静时间等指标值进行了通径分析。对41个蚁巢观察结果表明,除了1个蚁巢外,蚁巢惊扰后60 s时在观测尺平均爬升高度均大于15 s时平均爬升高度,且蚁巢被干扰后观测尺上工蚁数量和爬行高度随着时间的延长先快速增加,至45 s时达到最大,尔后逐渐减少至平静。相关分析表明,180 s内阳面平均爬行高度与测试时活动时间的相关性最高,恢复平静时间与蚁巢体积相关性最高,相关系数分别为0.4572和0.6233。通径分析表明,测试活动时间对15 s时阴面平均爬升高度、15 s时平均爬升高度及180 s内阳面平均爬行高度起正向作用,60 s时阴面平均爬升高度以及60 s时平均爬升高度与蚁巢体积起正向作用,蚁巢地表高度、蚁巢地表面积、蚁巢体积对恢复平静时间起正向作用。研究结果为了解热带地区大豆种植生境红火蚁行为活动特征,以及实施有效防控提供科学参考。

关键词：红火蚁工蚁活动性大豆田生境通径分析

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Microstructure Refinement of Mg-Gd-Y-Zr Alloy Under Pulsed Magnetic Field

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Journal of Iron and Steel Research International 2012年第S1期19卷 446-450页

作者： WANG Bin yang yuan-sheng College of Engineering Zhejiang Normal University Institute of Metal Research Chinese Academy of Sciences

The effects of pulsed magnetic field on the solidified microstructure of Mg-Gd-Y-Zr alloy were investigated. Fine uniform equiaxed grains are acquired in the whole ingot by the pulsed magnetic field treatment,and the average grain size of the as-cast φ50 mm and φ100 mm ingots is refined to 37 μm and 47 μm with the pulsed magnetic *** macrosegregation of solute elements of Mg-Gd-Y-Zr alloy is also reduced by the pulsed magnetic field treatment. Structure refinement is due to the electromagnetic undercooling zone in front of the solid/liquid interface by the magnetic pressure,and reduction of temperature gradient by the vibration of melt resulted from the pulsed magnetic field,which increases the nucleation rate and prohibits dendrite *** addition,primary α-Mg dendrites break into fine crystals, resulting in a refined solidification structure of the magnesium *** Joule heat effect induced in the melt also strengthens the grain refinement effect and the spheroidization of dendrite arms.

关键词： pulsed magnetic field solidified microstructure grain refinement Mg-Gd-Y-Zr alloy

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Recent Advances in Deciphering the Mechanisms and Biological Functions of DNA Demethylation

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Chinese Journal of Chemistry 2024年第6期42卷 645-651页

作者： yang Feng sheng-Jun Chen Bi-Feng yuan Key Laboratory of Aquatic Product Processing Ministry of Agriculture and Rural AffairsNational R&D Center for Aquatic Product ProcessingSouth China Sea Fisheries Research InstituteChinese Academy of Fishery SciencesGuangzhouGuangdong510300 China School of Public Health Research Center of Public HealthRenmin Hospital of Wuhan UniversityWuhan UniversityWuhanHubei430071 China

5-Methylcytosine (5mC) is a dynamic and reversible epigenetic modification in genomic DNA of higher *** has been well-established that the demethylation of 5mC occurs through the ten-eleven translocation (TET)-mediated oxidation of 5mC followed by thymine DNA glycosylase (TDG)-initiated base excision repair (BER).Recent findings also have identified an alternative pathway of DNA *** this pathway,TET enzymes directly oxidize 5mC to form 5-formylcytosine (5fC) or 5-carboxylcytosine (5caC).These modified bases can undergo direct deformylation or decarboxylation,***,DNA demethylation can also occur through the deamination of 5mC and 5hmC,resulting in the production of thymine and 5-hydroxymethyluracil (5hmU),*** DNA demethylation pathways possess critical functional implications and roles in biological *** Recent Advances article will focus on the studies of mechanisms and biological functions of DNA demethylation,shedding light on the reversible nature of the epigenetic modification of 5mC.

关键词： Epigenetics DNA DNA methylation 5-Methylcytosine Demethylation Mechanisms Biological functions C—C bond cleavage Mass spectrometry

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Numerical Simulation of Directional Solidification of a Nickel-Based Superalloy With Applied Direct Current

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Journal of Iron and Steel Research International 2012年第S1期19卷 158-161页

作者： FENG Xiao-hui yang yuan-sheng Institute of Metal Research Chinese Academy of Sciences

A macroscopic thermal field calculation and a microstructure simulation are performed to investigate the directional solidification of a nickel-based superalloy with applied direct current in this *** heat effects of electric current passing through the solidification interface as Joule heat and Peltier heat are investigated in the *** calculated result shows that the Joule heat improves the temperature gradient in the solidification interface,while the effect of Peltier heat is negligible for macroscopic thermal *** directional growth of dendrites under the influence of Joule heat is investigated with *** is found that under the influence of Joule heat,the dendrites are provided with self-adjustment ability of coordinating growth to achieve flat interface in macroscale during directional solidification with the direct electric *** interesting phenomenon is brought by the crowdedly passing through the dendrite of electric current in the solidification interface for the large difference of the electrical resistivity between solid state and melt of the superalloy.

关键词： directional solidification dendrite growth direct current Joule heat

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Effect of a Low-Voltage Pulsed Magnetic Field on the Microstructure and Mechanical Properties of AZ80 Alloy

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Journal of Iron and Steel Research International 2012年第S1期19卷 256-259页

作者： FU Jun-wei yang yuan-sheng Institute of Metal Research Chinese Academy of Sciences

Effect of a low-voltage pulsed magnetic field(LVPMF)on the solidified microstructure and mechanical properties of Mg-Al-Zn alloy was *** the LVPMF is applied during solidification,the as-cast microstructure is significantly refined and a-Mg is modified from developed dendrite to fine *** morphology modification is caused by the accumulation of Joule heat on dendrite *** of Joule heat on dendrite tip melts the dendrite tip and increases the radius of *** increased radius of curvature at the dendrite tip lowers the growth rate and results in the formation of rosette *** the application of the LVPMF,β precipitates,formed in the interdendritic liquid region,are connected to each other due to the smaller dimension of the primary and secondary arms and larger volume fraction of the β precipitates between the *** results indicate that the yield strength and ultimate tensile strength are both increased under with the application of the ***,elongation is slightly decreased with the application of the LVPMF due to the continuous β precipitates.

关键词： pulsed magnetic field microstructure mechanical properties AZ80 alloy

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Significant annealing-induced hardening effect in nanolaminate d-nanotwinne d(CrCoNi)_(97.4)Al_(0.8)Ti_(1.8)me dium-entropy alloy by severe cold rolling

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Journal of Materials Science & Technology 2024年第3期170卷 156-166页

作者： Shuqing yuan Hui Fu Lei Qian Chi Fai Cheung Xu-sheng yang State Key Laboratory of Ultra-precision Machining Technology Department of Industrial and Systems EngineeringThe Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina Hong Kong Polytechnic University Shenzhen Research Institute Shenzhen 518060China

Due to the easy coarsening caused by poor thermal stability,the verified annealing-induced hardening in nanograined metals can only maintain at a relatively low-temperature *** this study,a nanolam-inated(CrCoNi)_(97.4)Al_(0.8)Ti_(1.8)medium-entropy alloy with an average lamellae thickness of∼20 nm embedded by thinner nanotwins was fabricated by severe cold rolling to achieve superior thermal *** with the conventional nanotwinned CrCoNi with nanotwins inside ultra-fined grains,the hier-archical nanolaminated-nanotwinned(CrCoNi)_(97.4)Al_(0.8)Ti_(1.8) exhibits a significant annealing-induced hard-ening effect,i.e.,hardness increasing from∼250 HV in the original specimen to∼500 HV in the cold-rolled status and finally∼630 HV after annealing at 600℃for 1 *** microstructure characterizations reveal that the reduced dislocation density and formation of L1_(2)ordered domain are mainly responsible for such hardening effect,which is facilitated by the effectively suppressed coarsening with annealing temperature,i.e.,slow detwinning process and well-retained low-angle nanolamellar *** coarsening mechanisms from the cold-rolled nanolamellae to the fully recrystallized micro-equiaxed structures under the annealing temperatures ranging from 400 to 800℃ were also elucidated by atomic observations.

关键词： Annealing-induced hardening Thermal stability Nanolaminated-nanotwinned structure CrCoNi Detwinning Grain boundary migration

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Hydrodynamic characteristics and particle tracking of 90° lateral intakes at an inclined river slope

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Water Science and Engineering 2024年第2期17卷 197-208页

作者： Wei He Si-yuan Feng Jian Zhang Hong-wu Tang yang Xiao sheng Chen Chun-sheng Liu College of Water Conservancy and Hydropower Engineering Hohai UniversityNanjing 210098China State Key Laboratory of Hydrology Water Resources and Hydraulic Engineering Hohai UniversityNanjing 210098China Collaborative Innovation Center on Water Safety and Water Science Hohai UniversityNanjing 210098China

Lateral intakes are common in *** pump effciency and sediment deposition are determined by the local hydrodynamic characteristics and mainstream division *** hydraulic characteristics of lateral withdrawal from inclined river slopes at different intake elevations should be ***,the division width exhibits significant vertical non-uniformity at an inclined river slope,which should be ***,a three-dimensional(3-D)hydrodynamic and particle-tracking model was developed with the Open Source Field Operation and Manipulation(Open FOAM),and the model was validated with physical model tests for 90°lateral withdrawal from an inclined side *** flow fields,withdrawal sources,and division widths were investigated with different intake bottom elevations,withdrawal discharges,and main channel *** study showed that under inclined side bank conditions,water entered the intake at an oblique angle,causing significant 3-D spiral flows in the intake rather than two-dimensional closed recirculation.A lower withdrawal discharge,a lower bottom elevation of the intake,or a higher main channel velocity could further strengthen this *** average division width and turbulent kinetic energy were smaller under inclined side bank conditions than under vertical bank *** a low intake bottom elevation,a low withdrawal discharge,or a high main channel velocity,the sources of lateral withdrawal were in similar ranges near the local inclined bank in the vertical *** inclined slope conditions,sediment deposition near the intake entrance could be reduced,compared to that under vertical slope *** results provide hydrodynamic and sediment references for engineering designs for natural rivers with inclined terrains.

关键词： Lateral withdrawal Hydrodynamic characteristics Particle tracking Inclined river slope Bottom elevation of intake OpenFOAM

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Thermal and thermoelectric response from Keldysh formalism with application to gapped Dirac fermions

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Chinese Physics B 2015年第4期24卷 420-424页

作者：朱国宝杨慧敏杨声远 Department of Physics and Electronic Engineering Heze University Institute of Theoretical Physics Heze University Engineering Product Development Singapore University of Technology and Design

Based on the Keldysh Green’s functions theory, we present a general formula of the thermal and thermoelectric transport. In the clean limit, our formula recovers the previous results obtained from the semiclassical transport *** our approach, we propose an appropriate energy current operator and electric current operator, and the unphysical divergence from the direct application of the Kubo formula is eliminated. As an application, we study the thermal and the thermoelectric Hall conductivities of a gapped Dirac fermion model in the presence of impurity scattering.

关键词： thermal thermoelectric Green’s function

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Effect of electrolyte cation-mediated mechanism on electrocatalytic carbon dioxide reduction

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Chinese Chemical Letters 2024年第7期35卷 139-146页

作者： yuan Dong Mutian Ma Zhenyang Jiao sheng Han Likun Xiong Zhao Deng yang Peng Soochow Institute of Energy and Material Innovations College of EnergyJiangsu Key Laboratory of Advanced Carbon Materials and Wearable Energy TechnologiesSoochow UniversitySoochow 215006China Jiangsu Key Laboratory of Advanced Negative Carbon Technologies Soochow UniversitySoochow 215123China School of Chemistry and Chemical Engineering Shihezi UniversityShihezi 832003China School of Chemical and Environmental Engineering Shanghai Institute of TechnologyShanghai 201418China

The steep reduction in costs and systematic optimization of renewable electricity has ignited an intensifying interest in harnessing electroreduction of carbon dioxide(CO_(2)RR)for the generation of chemicals and *** focus of research over the past few decades has been on the optimization of the electrode and the electrolyte ***,cation species in the latter have recently been found to dramatically alter the selectivity of CO_(2)RR and even their catalytic activity by multiple orders of *** a result,the selection of cations is a critical factor in designing catalytic interfaces with high selectivity and efficiency for targeted *** decision-making regarding cation selection relies on a comprehensive understanding of prevailing electrolyte effect models that have been used to elucidate observed experimental *** this perspective,we review the hypotheses that explain how electrolyte cations influence CO_(2)RR by mechanisms such as through tuning of the interfacial electric field,buffering of the local pH,stabilization of the key intermediates and regulation of the interfacial *** endeavor is to elucidate the molecular mechanisms underpinning cation effects,thus fostering the evolution of more holistic and universally applicable predictive *** this regard,we highlight the current challenges in this area of research,while also identifying potential avenues for future investigations.

关键词： CO_(2)electrocatalytic reduction Cation effects Catalytic mechanisms Catalytic interfaces Electric double layer

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