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Chinese Physics B 2018年第11期27卷 55-70页

作者： Jinbo yang wenyun yang Zhuyin Shao Dong Liang Hui Zhao Yuanhua Xia Yunbo yang State Key Laboratory for Mesoscopic Physics School of PhysicsPeking UniversityBeijing 100871China Collaborative Innovation Center of Quantum Matter Beijing 100871China Beijing Key Laboratory for Magnetoelectric Materials and Devices Beijing 100871China Institutes of Nuclear Physics and Chemistry China Academy of Engineering PhysicsMianyang 621999China

Mn-based intermetallic compounds have attracted much attention due to their fascinating structural and physical properties,especially their interesting hard magnetic *** this paper,we have summarized the magnetic and structural properties of Mn-based intermetallic compounds(Mn X,where X=Al,Bi,and Ga).Various methods for synthesizing single phases of MnAl,MnBi,and Mnx Ga were developed in our lab.A very high saturation magnetization of 125 emu/g,coercivity of 5 kOe,and maximum energy product(BH)_(max)of 3.1 MG·Oe were achieved at room temperature for the pureτ-Mn–Al magnetic phase without carbon doping and the extrusion *** temperature phase(LTP)MnBi with a purity above 95 wt.%can be *** abnormal temperature coefficient of the coercivity was observed for the LTP MnBi *** coercivity increased with temperature from 100 K to 540 K,reached a maximum of 2.5 T at about540 K,and then decreased slowly to 1.8 T at 610 *** positive temperature coefficient of the coercivity is related to the evolution of the structure and magnetocrystalline anisotropy field of the LTP MnBi phase with *** LTP MnBi bonded magnets show maximum energy products(BH)_(max)of 8.9 MG·Oe(70 kJ/m^(3))and 5.0 MG·Oe(40 k J/m^(3))at room temperature and 400 K,*** Mn_(x)Ga phases with L10 structures(x〈2.0)and D0_(22)structures(x〉2.0)were *** of the above structures can be described by a D0_(22)supercell model in which 2 a-Ga and 2 b-Mn are simultaneously *** tetragonal D0_(22)phases of the Mn_(x)Ga show high coercivities ranging from 7.2 kOe for low Mn content x=1.8 to 18.2 kOe for high Mn content x=3 at room *** Mn_(1.2)Ga sample exhibits a room temperature magnetization value of 80 emu/*** hard magnetic properties of coercivityiH_(c)=3.5 kOe,remanence M_(r)=43.6 emu/g,and(BH)_(max)=2.5 MG·Oe were obtained at room *** on the above studies,we believe that Mn-based magnetic materials could

关键词： permanent magnetic materials magnetic properties manganese alloys magnetic structure coercivity magnetization neutron diffraction

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Tuning effect of silicon substitution on magnetic and high frequency electromagnetic properties of R2Fe17 and their composites

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Journal of Rare Earths 2019年第10期37卷 1102-1107页

作者： wenyun yang Qiwei Hu Guanyi Qiao Liang Zha Shunquan Liu Jingzhi Han Honglin Du Yan Zhang Yingchang yang Changsheng Wang State Key Laboratory for Mesoscopic Physics School of PhysicsPeking UniversityBeijing100871China Beijing Key Laboratory for Magnetoeletric Materials and Devices Beijing100871China

In this work, we report the tuning effect of the Si substitution on the magnetic and high frequency electromagnetic properties of R2 Fe17 compounds and their paraffin composites. It is found that the introduction of Si can remarkably improve the magnetic and electromagnetic properties of the R2 Fe17 compounds, making the R2 Fe17 exSix-paraffin composites excellent microwave absorption materials(MAMs). By introducing the Si element, their saturation magnetizations decrease slightly, while much higher Curie temperatures are obtained. Furthermore, better impedance match is reached due to the decrease of the high-frequency permittivity ε’ by about 40%e50%, which finally enhances the performance of the microwave absorption. The peak frequency(fRL) of the reflection loss(RL) curve moves toward high frequency domain and the qualified bandwidth(QB, RL≤-10 dB) increases remarkably. The maximum QB of 3.3 GHz(12.0 e15.3 GHz) is obtained for the Sm1.5 Y0.5 Fe15 Si2-paraffin composite(d = 1.0 mm) and the maximum RL of -53.6 dB is achieved for Nd2 Fe15 Si2-paraffin composite(d = 2.2 mm), both surpassing most of the reported MAMs. Additionally, a distinguished dielectric microwave absorption peak is observed, which further increases the QB in these composites.

关键词： Rare-earth transition-metal intermetallics Si substitution Magnetism Composites Microwave absorption properties

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High coercivity Nd-Ce-Fe-B nanostructured ribbons prepared from melt spinning technique

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Journal of Rare Earths 2019年第10期37卷 1053-1058页

作者： Liang Zha Zhou Liu Hao Chen Mingzhu Xue Guanyi Qiao Shilei Ding Xin Wen Meiling Zhang Youfang Lai wenyun yang Jingzhi Han Dong Zhou Chenyao Zhu Jinbo yang State Key Laboratory for Mesoscopic Physics School of PhysicsPeking UniversityBeijing100871China Institute of International Economy University of International Business and EconomicsBeijing100029China Functional Materials Research Institut5 Central Iron&Steel Research Institut5Beijing100081China Robotics Research Group College of EngineeringPeking UniversityBeijing100871China Collaborative Innovation Center of Quantum Matter Beijing100871China Beijing Key Laboratory for Magnetoelectric Materials and Devices Beijing100871China

The Ce-substituted(Nd1-xCex)12.2 Fe81.6 B6.2(x=0.0, 0.2, 0.4, 0.6) nanocrystalline ribbons were prepared by annealing amorphous ribbons from melt spinning. It is found that all ribbons are in a multiphase state consisting of a-Fe phase, Nd(Ce)-rich phases and RE2 Fe14 B(RE = Nd, Ce) phases. However, the coercivity of all annealed ribbons can reach a considerably high value without doping any heavy rare earth or other coercivity enhanced elements. A strong intergranular exchange coupling appears in these nanocrystalline ribbons. The Nd12.2 Fe81.6 B6.2 ribbons with multiphase have a coercivity of about 11.3 k Oe, and the coercivity decreases slightly with increasing Ce content. A coercivity of 7.5 kOe can be obtained when60 at% of Nd is replaced by Ce(x = 0.6) due to the grain refinement and the strong intergranular exchange coupling. This provides a practical approach of fabricating high coercivity Ce-substituted Nd-Fe-B materials.

关键词： Nd-Fe-B alloy Ce substitution Coercivity Rare earths

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Magnetic and Magnetocaloric Properties of Polycrystalline and Oriented Mn2-δSn

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Chinese Physics Letters 2019年第9期36卷 68-71页

作者： Kun Li Fanggui Wang Youfang Lai Mingzhu Xue Xin Li Jinbo yang Changsheng Wang Jingzhi Han Shunquan Liu wenyun yang Yingchang yang Honglin Du School of Physics Peking UniversityBeijing 100871 Beijing Key Laboratory for Magnetoelectric Materials and Devices Beijing 100871 Collaborative Innovation Center of Quantum Matter Beijing 100871

Mn-based Heusler alloys have attracted significant research attention as half-metallic materials because of their giant *** anisotropy and magnetocaloric *** investigate the crystal structure and magnetic properties of polycrystalline,[101]-oriented,and[100]-oriented Mn2-δ Sn prepared separately by arc melting,the Bridgeman method,and the flux *** of these compounds crystallize in a Ni2 In-type *** the Mn2-δSn lattice,Mn atoms occupy all of the 2 a and a fraction of the 2 d *** disorder exists between Mn and Sn atoms in the 2 c *** addition,these compounds undergo a re-entrant spin-glass-like transition at low temperatures,which is caused by frustration and randomness within the spin *** magnetic properties of these systems depend on the crystal directions,which means that the magnetic interactions differ significantly along different ***,these materials exhibit a giant magnetocaloric effect near the Curie *** largest value of maximum of magnetic entropy change(-△SM)occurs perpendicular to the[100]***,at 252 K,maximum-△SM is 2.91 and 3.64 J-kg-1K-1 for a magnetic field of 5 and7 T,*** working temperature span over 80 K and the relative cooling power reaches 302 J/kg for a magnetic field of 7 T,which makes the Mn2-δSn compound a promising candidate for a magnetic refrigerator.

关键词： Magnetic and Magnetocaloric Properties of Polycrystalline and Oriented Mn Sn

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Structural and Magnetic Properties of Nanocomposite Nd Fe BPrepared by Rapid Thermal Processing

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Engineering 2020年第2期6卷 132-140页

作者： Jinbo yang Jingzhi Han Haidong Tian Liang Zha Xiongzuo Zhang Chol Song Kim Dong Liang wenyun yang Shunquan Liu Changsheng Wang State Key Laboratory for Artificial Microstructure and Mesoscopic Physics School of PhysicsPeking UniversityBeijing 100871China Collaborative Innovation Center of Quantum Matter School of PhysicsPeking UniversityBeijing 100871China Beijing Key Laboratory for Magnetoelectric Materials and Devices Collegue of EngineeringPeking UniversityBeijing 100871China

Nanoscale permanent magnetic materials,which possess excellent magnetic and mechanical properties,thermal stability,and corrosion resistance,have become a research hotspot for permanent *** reality,however,the obtained maximum energy product,(BH)max,is not satisfactory in comparison with the theory limit,especially for exchange-coupled nanocomposite *** construction of an ideal microstructure still remains a challenge in the synthesis and preparation of nanoscale permanent *** work reported the impact of rapid thermal process(RTP)with electron-beam heating on the microstructures of Nd12.5-xFe80.8+xB6.2Nb0.2Ga0.3(x=0,2.5)*** was found that the crystallization time was greatly reduced,from 15 min under the conventional annealing conditions to 0.1 s under the *** Nd2Fe14B single-phase materials,the crystallization temperature of the RTP ribbons decreased by about 248 C compared with that of the ribbons produced by the conventional annealing method.A synergetic crystallization of the Nd2Fe14B and a-Fe phases was observed under the RTP,which restrained not only the shape,size distribution,and compositions of the hard and the soft phases,but also the interface between *** modification effect became more obvious as the fraction of Fe *** to the improvement in the uniformity of the Nd2Fe14B and a-Fe phases,and their grain size distribution,better magnetic properties were achieved using RTP in comparison with the conventional annealing method.

关键词： Nanocomposites Electron-beam heating Landau model and Langevin dynamics simulation Synergetic crystallization

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Tuning anionic/cationic redox chemistry in a P2-type Na0.67Mn0.5Fe0.5O2 cathode material via a synergic strategy

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Science China Materials 2020年第9期63卷 1703-1718页

作者： Weijin Kong wenyun yang De Ning Qingyuan Li Lirong Zheng Jinbo yang Kai Sun Dongfeng Chen Xiangfeng Liu Center of Materials Science and Optoelectronics Engineering College of Materials Science and Optoelectronic TechnologyUniversity of Chinese Academy of SciencesBeijing 100049China State Key Laboratory for Mesoscopic Physics School of PhysicsPeking UniversityBeijing 100871China Helmholtz-Center Berlin for Materials and Energy Hahn-Meitner-Platz 1Berlin 14109Germany Beijing Synchrotron Radiation Facility Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China Department of Nuclear Physics China Institute of Atomic EnergyBeijing 102413China CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of SciencesBeijing 100190China

The anionic redox chemistry(O^2-→O^-)in P2-type sodium-ion battery cathodes has attracted much ***,determining how to tune the anionic redox reaction is still a major ***,we tune the activity and reversibility of both the anionic and cationic redox reactions of Na0.67Mn0.5Fe0.5O2 though an integrated strategy that combines the advantages of Li2SiO3 coating,Li doping and Si doping,and the initial capacity,rate performance and cycling stability are significantly *** in-depth modulation mechanism is revealed by means of neutron diffraction,X-ray absorption spectroscopy,in situ X-ray diffraction,electron paramagnetic resonance spectroscopy,first-principles calculations and so *** Li2SiO3 coating alleviates the side reactions and enhances the cycling ***^4+doping lowers the Na^+diffusion barrier due to the expanded interlayer ***,Si^4+doping improves the structural stability,oxygen redox activity and ***^+doping in Na sites further increases the structure *** electron density maps confirm the greater activity of Na and O in the modified *** density maps and bond-valence energy landscapes identify the Na^+migration pathway from Nae site to Naf site(the positions of the Na ions in the crystal structure).The proposed insights into the modulation mechanism of the anionic and cationic redox chemistry are also instructive for designing other oxide-based cathode materials.

关键词： sodium-ion battery P2-type cathode anion redox electron density nephogram Li2SiO3 coating

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非制冷红外探测器研究进展(特邀)

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红外与激光工程 2021年第1期50卷 63-77页

作者：余黎静唐利斌杨文运郝群北京理工大学光电学院信息光子技术工信部重点实验室北京100081 昆明物理研究所云南昆明650223 云南省先进光电材料与器件重点实验室云南昆明650223

非制冷红外探测器由于无需制冷装置,能够工作在室温状态下,具有成本低、体积小、功耗低等特点,在红外领域得到了广泛的应用。在军事应用方面,非制冷型探测器的应用逐渐进入了之前制冷型探测器的应用范围,大量应用在一些低成本的武器系统... 详细信息

非制冷红外探测器由于无需制冷装置,能够工作在室温状态下,具有成本低、体积小、功耗低等特点,在红外领域得到了广泛的应用。在军事应用方面,非制冷型探测器的应用逐渐进入了之前制冷型探测器的应用范围,大量应用在一些低成本的武器系统,甚至在一些应用领域取代了原来的非制冷型探测器。在民用领域方面,更表现出了其价格和使用方便的优势,在民用车载夜视、安防监控等应用领域引起了广泛的兴趣和关注。文中介绍了Bolometer、热释电、热电堆等几种典型非制冷红外探测器的工作原理,列举了目前已实现商业化应用的主要产品在国内外的情况,着重介绍了目前应用最广泛的Bolometer器件主流产品的像元间距、阵列规格、性能及其封装发展的情况。除了已实现商业化应用的Bolometer、热释电、SOI二极管等探测器等产品,还详细介绍了一些非制冷探测新技术或新型器件:比如超表面在增强某些波段吸收方面的应用,新材料的Bolometer探测器、双材料新型非制冷器件、石墨烯、量子点、纳米线等光电探测技术的研究进展。最后文章还对今后非制冷红外探测器的发展趋势作了预测。

关键词：非制冷红外探测器热释电 Bolometer 封装

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A novel strategy for the fabrication of highperformance nanostructured Ce-Fe-B magnetic materials via electron-beam exposure

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Science China Materials 2021年第10期64卷 2519-2529页

作者： Liang Zha Cholsong Kim Chao Yun Dong Zhou Wei Li Xiangdong Kong Li Han wenyun yang Shunquan Liu Jingzhi Han Changsheng Wang Honglin Du Weixing Xia Alberto Bollero Jinbo yang State Key Laboratory for Mesoscopic Physics School of PhysicsPeking UniversityBeijing 100871China Functional Materials Research Institute Central Iron&Steel Research InstituteBeijing 100081China Department of Micro-Nano Fabrication Technology Institute of Electrical EngineeringChinese Academy of SciencesBeijing 100190China Key Laboratory of Magnetic Materials and Devices Ningbo Institute of Material Technology and EngineeringChinese Academy of SciencesNingbo 315201China Division of Permanent Magnets and Applications IMDEA NanoscienceMadridSpain Collaborative Innovation Center of Quantum Matter Beijing 100871China Beijing Key Laboratory for Magnetoelectric Materials and Devices Beijing 100871China

Ce_(2)Fe_(14)B compound has a great potential to serve as a novel permanent magnet alternative thanks to the abundant and inexpensive rare-earth element(cerium),while its low magnetocrystalline anisotropy and energy product severely restrict its *** this work,a novel strategy combining melt-spinning and electron-beam exposure(EBE)aiming for fabricating high-performance Ce-Fe-B magnetic materials is reported to solve the above-mentioned ***,this strategy facilitates developing a suitable grain boundary configuration without using any additional heavy rare-earth *** the optimal EBE condition,the maximum energy product((BH)max)of pure Ce-Fe-B alloy is 6.5 MGOe,about four times higher than that obtained after conventional rapid thermal processing method for the same *** enhanced intergranular magnetostatic coupling effect in the EBE sample is validated by mapping the first-order-reversal-curve(FORC)*** in-situ observation of magnetic domain wall motion for Ce-Fe-B alloy using Lorentz transmission electron microscopy reveals that the boundary layers are very effective in pinning the motion of domain walls,leading to the increased coercivity under EBE,and this pinning effect is further verified by micromagnetic *** results suggest that Ce Fe B materials using EBE could be a promising candidate after further processing,which could fill the performance“gap”between hexaferrite and Nd-Fe-B-based magnets.

关键词： nanoscale magnets rapid thermal annealing Ce-Fe-B magnetic properties nanocrystalline material

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TITE(e)-U-Keyboard两阶段Ⅰ/Ⅱ期试验设计研究

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中国卫生统计 2023年第6期40卷 811-816页

作者：何娟杨文韫张语澄言方荣中国药科大学生物统计与计算药学研究中心 210009

目的针对肿瘤靶向制剂和细胞免疫疗法治疗效应延迟的问题,基于Ⅰ/Ⅱ期试验设计框架,构建创新试验设计方法TITE(e)-U-Keyboard。方法采用二项近似似然法纳入尚未观测到的有效性结局信息,构建近似分布,辅助决策,并将TITE(e)-U-Keyboard同... 详细信息

目的针对肿瘤靶向制剂和细胞免疫疗法治疗效应延迟的问题,基于Ⅰ/Ⅱ期试验设计框架,构建创新试验设计方法TITE(e)-U-Keyboard。方法采用二项近似似然法纳入尚未观测到的有效性结局信息,构建近似分布,辅助决策,并将TITE(e)-U-Keyboard同Ⅰ/Ⅱ期试验设计方法U-BOIN、BOIN12从多个角度进行模拟比较研究。结果模拟结果显示在考虑有效性结局延迟的情况下三种方法的OBD选择准确率及最优剂量分配受试者数相当,但TITE(e)-U-Keyboard所需试验时长最短;敏感性分析表明有效性观察窗会对TITE(e)-U-Keyboard试验时长产生影响,且随着有效性观察窗的增加而增加。结论TITE(e)-U-Keyboard在保持良好试验设计性能的同时显著缩短了试验时长,可以解决Ⅰ/Ⅱ期临床试验中治疗效应延迟的问题,加速临床试验进程。

关键词：有效性延迟 Ⅰ/Ⅱ期试验两阶段设计

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核心素养视域下高中地理课堂教学改革探研

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成才之路 2023年第19期 53-56页

作者：杨文云云南省普洱市第一中学云南普洱665000

借助地理课堂培养学生核心素养,已成为教学改革的热点问题。改革高中地理课堂教学一是要优化地理课堂教学方法,增添教学趣味性;二是要创新地理课堂教学手段,激发教学活力;三是要设计提问式课堂,培养学生探究能力;四是要融入生活元素,丰... 详细信息

借助地理课堂培养学生核心素养,已成为教学改革的热点问题。改革高中地理课堂教学一是要优化地理课堂教学方法,增添教学趣味性;二是要创新地理课堂教学手段,激发教学活力;三是要设计提问式课堂,培养学生探究能力;四是要融入生活元素,丰富学生生活经验;五是要延伸地理课外活动,帮助学生积累实践经验;六是要重视提升教师能力素养,优化教学机制;七是要开展多元化评价,提高教学效率。

关键词：高中地理核心素养教学策略教学改革思维能力实践能力

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