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Design and implementation of the monochromator shielding for the cold neutron spectrometers XINGZHI and BOYA

Chinese Physics B 2024年第5期33卷 96-102页

作者：汪晋辰刘娟娟徐大业 Florian Grünauer 郝丽杰刘蕴韬张红霞程鹏鲍威 laboratory for neutron scattering and Beijing Key laboratory of Optoelectronic Functional Materials and MicroNano Devices Department of PhysicsRenmin University of ChinaBeijing 100872China Physics Consulting Zorneding 85604Germany China Institute of Atomic Energy Beijing 102413China Department of Physics City University of Hong KongKowloon 999077China Center for neutron scattering City University of Hong KongKowloon 999077China

An innovative monochromator shielding is designed and implemented for the cold neutron spectrometers XINGZHI and BOYA operated by Renmin University of China at China Advanced Research Reactor.Via Monte Carlo simulations and careful mechanical designs,a shielding configuration has been successfully developed to satisfy safety requirements of below 3μSv/h dose rate at its exterior,meanwhile fulfilling space,floor load and nonmagnetic requirements.Composite materials are utilized to form the sandwich-type shielding walls:the inner layer of boron carbide rubber,the middle layer of steel-encased lead and the outer layer of borated polyethylene.Special-shaped liftable shielding blocks are incorporated to facilitate a continuous adjustment of the neutron energy while preventing radiation leakage.Our work has demonstrated that by utilizing composite shielding materials,along with the sandwich structure and liftable shielding blocks,a compact and lightweight shielding solution can be achieved.This enables the realization of advanced neutron scattering instruments that provide expanded space of measurement,larger energy and momentum coverage,and higher flux on the sample.This shielding represents the first of its kind in neutron scattering instruments in China.Following its successful operation,it has been subsequently employed by other neutron instruments across the country.

关键词： neutron scattering cold neutron spectrometer monochromator shielding sandwich shielding structure

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Boron-doped high-entropy oxide toward high-rate and long-cycle layered cathodes for wide-temperature sodium-ion batteries

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Journal of Energy Chemistry 2024年第8期95卷 577-587页

作者： Yuzhen Dang Zhe Xu Yurong Wu Runguo Zheng Zhiyuan Wang Xiaopin Lin Yanguo Liu Zheng-Yao Li Kai Sun Dongfeng Chen Dan Wang School of Materials Science and Engineering Northeastern University School of Resources and Materials Northeastern University at Qinhuangdao Key laboratory of Dielectric and Electrolyte Functional Material Hebei Province neutron scattering laboratory Department of Nuclear Physics China Institute of Atomic Energy

03-type layered metal oxides hold great promise for sodium-ion batteries cathodes owing to their energy density advantage.However,the severe irreversible phase transition and sluggish Na+diffusion kinetics pose significant challenges to achieve high-performance layered cathodes.Herein,a boron-doped03-type high entropy oxide Na(Fe0.2Co0.15Cu0.05Ni0.2Mn0.2Ti0.2)B0.02O2(NFCCNMT-B0.02) is designed and the covalent B-O bonds with high entropy configuration ensure a robust layered structure.The obtained cathode NFCCNMT-B0.02exhibits impressive cycling performance（capacity retention of 95% and 82% after100 cycles and 300 cycles at 1 and 10 C,respectively） and outstanding rate capability(capacity of 83 mAh g-1at 10 C).Furthermore,the NFCCNMT-B0.02demonstrates a superior wide-temperature performance,maintaining the same capacity level(113,4 mAh g-1@-20℃,121 mAh g-1@25℃,and 119 mAh g-1@60℃) and superior cycle stability（90% capacity retention after 100 cycles at 1 C at-20℃）.The high-entropy configuration design with boron doping strategy contributes to the excellent sodium-ion storage performance.The high-entropy configuration design effectively suppresses irreversible phase transitions accompanied by small volume changes（ΔV=0.65 ?3）.B ions doping expands the Na layer distance and enlarges the P3 phase region,thereby enhancing Na+diffusion kinetics.This work offers valuable insights into design of high-performance layered cathodes for sodium-ion batteries operating across a wide temperature.

关键词： Born substitution High entropy oxide Na+ diffusion kinetics Phase transition Sodium-ion batteries

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Anomalous thermal expansion and enhanced magnetocaloric effect in <001>-textured MnxFe5–xSi3alloys

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Rare Metals 2024年第5期43卷 2263-2274页

作者： Yong Gong Xue-Fei Miao Tapas Samanta Chris Taake Jun Liu Feng-Jiao Qian Yan-Yan Shao Yu-Jing Zhang Qing-Yong Ren Luana Caron Feng Xu MIIT Key laboratory of Advanced Metallic and Intermetallic Materials Technology School of Materials Science and Engineering Nanjing University of Science and Technology Department of Physics Bielefeld University College of Physics Nanjing University of Aeronautics and Astronautics Institute of High Energy Physics Chinese Academy of Sciences Spallation neutron Source Science Center Guangdong-Hong Kong-Macao Joint laboratory for neutron scattering Science and Technology Helmholtz-Zentrum Berlin fu¨r Materialien und Energie

The development of zero and negative therma expansion （i.e.,ZTE and NTE） materials is of crucial importance to the control of undesirable thermal expansion for high-precision devices.In the present work,ZTE and NTE were obtained in directionally-solidified MnxFe5–xSi3alloys with a strongtexture,in striking contrast to positive thermal expansion in their isotropic counterparts Magnetometry and in-situ X-ray diffraction （XRD） measurements were performed to uncover the origin of the anomalous thermal expansion.Magnetic measurements indicate a strong easy-plane magnetocrystalline anisotropy in the textured samples,where the magnetic moments are aligned within the ab plane of the hexagonal structure Temperature-dependent XRD on the x=1 sample reveals a ZTE character in the ab plane that is coupled to a ferromagnetic transition.As a result,the macroscopic ZTE(～0.22×10–6K-1) in the x=1 sample can be attributed to the microscopic magneto volume effect within the ab plane,which is realized by the introduction of the-textured microstructure.Besides,the competition between antiferromagnetic and ferromagnetic exchange coupling leads to NTE in textured x=1.5 and 2 samples.Additionally,textured x=1 sample displays enhanced magnetocaloric properties as compared to the conventional counterparts with randomly-oriented grains.Consequently this work demonstrates a new strategy toward the exploration of anomalous thermal expansion properties as well as the enhancement of magnetocaloric properties for materials with a strong magnetocrystalline anisotropy.

关键词： MnFe 4 Si 3 Magnetocaloric effect Magnetic phase transition Negative thermal expansion

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Carbon Fiber Breakage Mechanism in Aluminum(Al)/Carbon Fibers(CFs) Composite Sheet during Accumulative Roll Bonding(ARB) Process

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Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 167-173页

作者：胡淑芬 SUN Zhenzhong SHEN Fanghua DENG Jun 杨卫平杨浩坤 School of Engineering Jiangxi Agricultural UniversityNanchang 330045China School of Mechanical Engineering Dongguan University of TechnologyDongguan 510730China Guangdong-Hong Kong-Macao Joint laboratory for neutron scattering Science and Technology Dongguan 510730China Smart Manufacturing Division Hong Kong Productivity Council78 Tat Chee AvenueHong Kong 5999075China

We put forward a method of fabricating Aluminum(Al)/carbon fibers(CFs) composite sheets by the accumulative roll bonding(ARB) method. The finished Al/CFs composite sheet has CFs and pure Al sheets as sandwich and surface layers. After cross-section observation of the Al/CFs composite sheet, we found that the CFs discretely distributed within the sandwich layer. Besides, the tensile test showed that the contribution of the sandwich CFs layer to tensile strength was less than 11% compared with annealed pure Al sheet. With ex-situ observation of the CFs breakage evolution with-16%,-32%, and-45% rolling reduction during the ARB process, the plastic instability of the Al layer was found to bring shear damages to the CFs. At last, the bridging strengthening mechanism introduced by CFs was sacrificed. We provide new insight into and instruction on Al/CFs composite sheet preparation method and processing parameters.

关键词： Al/CFs composite sheet accumulative roll bonding tensile strength plastic instability carbon fiber breakage

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Magnetic and electrical transport properties in GdAlSi and SmAlGe

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Chinese Physics B 2024年第7期 564-571页

作者：巩静王欢马小平曾祥雨林浚发韩坤王乙婷夏天龙 Department of Physics Renmin University of China Beijing Key laboratory of Opto-electronic Functional Materials & Micro-nano Devices Renmin University of China Key laboratory of Quantum State Construction and Manipulation (Ministry of Education) Renmin University of China laboratory for neutron scattering Renmin University of China

We conduct a detailed examination of the magnetic and electrical transport properties in GdAlSi and SmAlGe crystals,which possess a LaPtSi-type structure（space group I41md）.The magnetic susceptibility data unambiguously reveal magnetic ordering below a characteristic transition temperature（TN）.For GdAlSi,a hysteresis loop is observed in the magnetization and magnetoresistance curves within the ab plane when the magnetic field is applied below TN,which is around32 K.Notable specific heat anomalies are detected at 32 K for GdAlSi and 6 K for SmAlGe,confirming the occurrence of magnetic transitions.In addition,the extracted magnetic entropy at high temperatures is consistent with the theoretical value of Rln（2J+1） for J=7/2 in Gd3+and J=5/2 in Sm3+,respectively.SmAlGe also exhibits Schottky-like specific heat contributions.Additionally,both GdAlSi and SmAlGe exhibit positive magnetoresistance and a normal Hall effect.

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Tracing monoclinic distortion in NCM532 cathode materials by in situ high-energy synchrotron X-ray diffraction

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Progress in Natural Science:Materials International 2024年第2期34卷 274-279页

作者： Min Dong Qingya Sun Zhihua Wang Zixin Rui Zhe Zhang He Zhu Si Lan Herbert Gleiter Institute of Nanoscience School of Materials Science and Engineering Nanjing University of Science and Technology School of Mechanical Engineering Nanjing University of Science and Technology School of Materials Science and Engineering Henan University of Technology Center for neutron scattering City University of Hong Kong Shenzhen Research Institute

Layered LiNixCoyMnzO2（NCM） cathode materials have emerged as the best choice for high-energy-density lithium-ion batteries for powering electric vehicles.Despite significant research efforts,the understanding of complex structural dynamics during lithium（de-） intercalation still remains a subject of debate,especially in scenarios where morphology and composition vary.In this study,we carried out in situ high-energy synchrotron X-ray diffraction experiments on commercial NCM523cathode materials in both single crystal and polycrystalline forms to probe the structural changes during charging and discharging in detail.Our findings reveal that both single crystal and polycrystalline materials exhibit typical H1-H2-H3 phase transitions.However,in polycrystalline NCM532,a monoclinic intermediate phase emerges between the H1 and H2 phases.During this process,symmetry reduces from R-3m to C2/m,which is attributed to a shear distortion along the ab plane.In contrast,for single crystal materials,the H1 phase directly transforms into the H2 phase without the monoclinic phase.The observed monoclinic distortion significantly impacts structural stability and material cycling performance.This study provides new insight into the structural dynamics in NCM532 cathode materials,particularly concerning morphology-dependent behaviors,which could deepen our understanding of the relationship between NCM material structures and their performance.

关键词： CHEMISTRY

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Angular and planar transport properties of antiferromagnetic V5S8

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Chinese Physics B 2024年第2期33卷 83-88页

作者：吴晓凯王彬吴德桐陈博文弭孟娟王以林沈冰 Center for neutron Science and Technology and School of Physics Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devicesand Key Laboratory of Optoelectronic Materials and Technologies Sun Yat-Sen University School of Integrated Circuits Shandong Technology Center of Nanodevices and Integration State Key Laboratory of Crystal MaterialsShandong University

Systemically angular and planar transport investigations are performed in layered antiferromagnetic(AF) V5S8. In this AF system, obvious anomalous Hall effect(AHE) is observed with a large Hall angle of 0.1 compared to that in ferromagnetic(FM) system. It can persist to the temperatures above AF transition and exhibit strong angular field dependence.The phase diagram reveals various magnetic states by rotating the applied field. By analyzing the anisotropic transport behavior, magnon contributions are revealed and exhibit obvious angular dependence with a spin-flop vanishing line. The observed prominent planar Hall effect and anisotropic magnetoresisitivity exhibit two-fold systematical angular dependent oscillations. These behaviors are attributed to the scattering from spin–orbital coupling instead of nontrivial topological origin. Our results reveal anisotropic interactions of magnetism and electron in V5S8, suggesting potential opportunities for the AF spintronic sensor and devices.

关键词： antiferromagnetism magnetic and topological properties planar Hall effect

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Topological Confinement in Reversibly Interlocked Polymer Networks

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Chinese Journal of Polymer Science 2024年第2期42卷 133-140,I0004页

作者： Wan-Ting Dai Zhen-Hua Xie Yu-Bin Ke Yang You Min-Zhi Rong Ming-Qiu Zhang Key laboratory for Polymeric Composite and Functional Materials of Ministry of Education GD HPPC LabIGCMESchool of ChemistrySun Yat-sen UniversityGuangzhou510275China Spallation neutron Source Science Center China Spallation Neutron SourceDongguan523803China Institute of High Energy Physics Chinese Academy of SciencesBeijing100049China College of Materials and Metallurgy Guizhou UniversityGuiyang550025China

Recently, we reported a series of reversibly interlocked polymer networks(RILNs), whose mechanical robustness and functionalities improvement was believed to be derived from topological interlocking of two sub-networks, although the direct evidence for the deduction is still lacking. Herein, a specially-designed RILNs system, in which the inter-component hydrogen bonds can be shielded as needed, was prepared and used to study the micro-structures of RILNs, aiming to verify the existence of mechanical interlocking in RILNs. By changing the pH of the swelling solvent, the effect exerted by the inter-component non-covalent bonds was eliminated, so detailed information of the networks structure was exposed. The small angle X-ray scattering(SAXS) and small-angle neutron scattering(SANS) results indicated that swelling-induced structural evolution of the two sub-networks mutually affected each other, even when the inter-component hydrogen bonds were absent, proving the presence of topological interlocking. The findings may help to draw a more accurate physical image and reveal the detailed structureproperty relationship of RILNs.

关键词： Reversibly interlocked polymer networks Small angle X-ray scattering Small-angle neutron scattering Topological confinement

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P-and SV-wave dispersion and attenuation in saturated microcracked porous rock with aligned penny-shaped fractures

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Petroleum Science 2024年第1期21卷 143-161页

作者： Sheng-Qing Li Wen-Hao Wang Yuan-Da Su Jun-Xin Guo Xiao-Ming Tang School of Geosciences China University of Petroleum(East China)Qingdao 266580ShandongChina Laoshan National laboratory Qingdao 266071ShangdongChina Guangdong Provincial Key laboratory of Geophysical High-resolution imaging Technology Southern University of Science and TechnologyShenzhen 518055GuangdongChina Department of Earth and Space Sciences Southern University of Science and TechnologyShenzhen 518055GuangdongChina

P-and SV-wave dispersion and attenuation have been extensively investigated in saturated poroelastic media with aligned fractures.However,there are few existing models that incorporate the multiple wave attenuation mechanisms from the microscopic scale to the macroscopic scale.Hence,in this work,we developed a unified model to incorporate the wave attenuation mechanisms at different scales,which includes the microscopic squirt flow between the microcracks and pores,the mesoscopic wave-induced fluid flow between fractures and background(FB-WIFF),and the macroscopic Biot's global flow and elastic scattering(ES)from the fractures.Using Tang's modified Biot's theory and the mixed-boundary conditions,we derived the exact frequency-dependent solutions of the scattering problem for a single penny-shaped fracture with oblique incident P-and SV-waves.We then developed theoretical models for a set of aligned fractures and randomly oriented fractures using the Foldy approximation.The results indicated that microcrack squirt flow considerably influences the dispersion and attenuation of P-and SV-wave velocities.The coupling effects of microcrack squirt flow with the FB-WIFF and ES of fractures cause much higher velocity dispersion and attenuation for P waves than for SV waves.Randomly oriented fractures substantially reduce the attenuation caused by the FB-WIFF and ES,particularly for the ES attenuation of SV waves.Through a comparison with existing models in the limiting cases and previous experimental measurements,we validated our model.

关键词： Aligned fractures P-and SV-wave Dispersion and attenuation Microcracked porous background FB-WIFF Elastic scattering Squirt flow

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Angular and planar transport properties of antiferromagnetic V_(5)S_(8)

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Chinese Physics B 2024年第2期33卷 66-71页

作者：吴晓凯王彬吴德桐陈博文弭孟娟王以林沈冰 Center for neutron Science and Technology and School of Physics Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devicesand Key Laboratory of Optoelectronic Materials and TechnologiesSun Yat-Sen UniversityGuangzhou 510275China School of Integrated Circuits Shandong Technology Center of Nanodevices and IntegrationState Key Laboratory of Crystal MaterialsShandong UniversityJinan 250100China

Systemically angular and planar transport investigations are performed in layered antiferromagnetic(AF)V_(5)S_(8).In this AF system,obvious anomalous Hall effect(AHE)is observed with a large Hall angle of 0.1 compared to that in ferromagnetic(FM)system.It can persist to the temperatures above AF transition and exhibit strong angular field dependence.The phase diagram reveals various magnetic states by rotating the applied field.By analyzing the anisotropic transport behavior,magnon contributions are revealed and exhibit obvious angular dependence with a spin-flop vanishing line.The observed prominent planar Hall effect and anisotropic magnetoresisitivity exhibit two-fold systematical angular dependent oscillations.These behaviors are attributed to the scattering from spin–orbital coupling instead of nontrivial topological origin.Our results reveal anisotropic interactions of magnetism and electron in V5S8,suggesting potential opportunities for the AF spintronic sensor and devices.

关键词： antiferromagnetism planar Hall effect magnetic and topological properties

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