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多孔灰岩局部化变形的精细化描述与数字表征

大地构造与成矿学 2024年第3期48卷 547-556页

作者：武岳彪孟范宝王岳军 Patrick Baud 黄庭芳中山大学地球科学与工程学院广东珠海519082 香港中文大学理学院地球与环境科学课程中国香港999077 Universitéde Strasbourg CNRSInstitute Terre et Environnement de StrasbourgUMR 70635 Rue RenéDescartesStrasbourg cedex 67084France Department of Geosciences Stony Brook UniversityStony Brook NY 11794USA

压实带是一种典型的应变局部化现象,影响储层流体的封存、输运以及地下岩体的稳定性。多孔灰岩局部化变形的相关研究一直是难点,不像砂岩样品可以通过明显的声发射信号特征来分析与表征压实带的形成与演化规律。本文利用动态CT技术,实... 详细信息

压实带是一种典型的应变局部化现象,影响储层流体的封存、输运以及地下岩体的稳定性。多孔灰岩局部化变形的相关研究一直是难点,不像砂岩样品可以通过明显的声发射信号特征来分析与表征压实带的形成与演化规律。本文利用动态CT技术,实时监测灰岩局部化变形到宏观失稳的演化过程,重点描述压实带形成初期的局部化变形特征,涵盖了应变量>5%的变形部分特征。在灰岩变形过程中可以识别两处明显非弹性变形阶段:即初始大孔隙坍塌阶段和后续压实带形成过程,利用图像体积互相关技术定量表征压实带的演化特征,精细化描述压实带形成过程的微观破裂特征,系统分析离散压实带内的连通孔隙分布规律,发现连通孔隙与局部化变形有紧密联系,并基于CT扫描的孔隙网络数据,利用纳维斯特斯方程计算绝对渗透率,以渗透率为参考指标,研究局部化变形引起的损伤程度。

关键词：局部化变形 CT技术灰岩孔隙网络

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混合溶剂调控插层FeSe基超导体的层间距

Science China Materials 2024年第1期67卷 295-300页

作者：胡国兵石孟竹孟凡保江风云高敏钟钒陈欢郭景锋罗习刚 Physical Science and Technology College Yichun UniversityYichun 336000China Key Laboratory of Strongly Coupled Quantum Matter Physics Chinese Academy of SciencesHefei National Laboratory for Physical Sciences at Microscaleand Department of PhysicsUniversity of Science and Technology of ChinaHefei 230026China

近年来,通过湿化学方法探索合成新型插层FeSe基超导体一直是凝聚态物理的研究热点之一.本文中,我们利用溶剂热离子交换技术成功合成出两种FeSe衍生物:c轴晶胞参数为9.93Å的Li_(0.34)Se_(0.05)(EG)_(0.14)-FeSe和c轴晶胞参数为13.85Å的Li... 详细信息

近年来,通过湿化学方法探索合成新型插层FeSe基超导体一直是凝聚态物理的研究热点之一.本文中,我们利用溶剂热离子交换技术成功合成出两种FeSe衍生物:c轴晶胞参数为9.93Å的Li_(0.34)Se_(0.05)(EG)_(0.14)-FeSe和c轴晶胞参数为13.85Å的Li_(0.21)Se_(0.05)(EG)_(0.26)FeSe.通过调整反应溶剂可以调控以上两种FeSe衍生物的层间距.磁化率和电阻率测试表明它们的超导转变温度(Tc)均为30 K左右,似乎与FeSe层层间距的大小无关.与原始FeSe单晶相比,X射线光电子能谱结果显示FeSe层Fe的价态降低,这表明Tc的提高可能是由于电子掺杂效应引起的.我们的研究为探索合成插层铁基超导体提供了有价值的参考,并为在超导领域探索新型插层材料提供了新的可能性.

关键词：超导转变温度凝聚态物理 X射线光电子能谱铁基超导体混合溶剂离子交换技术湿化学方法反应溶剂

Controllable fabrication of nitrogen-doped porous nanocarbons for high-performance supercapacitors via supramolecular modulation strategy

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Journal of Energy Chemistry 2020年第10期29卷 348-357页

作者： Huaxia Chen Xingyu Lu Haihua Wang Dianpeng Sui fanbao meng Wei Qi Department of Chemistry College of ScienceNortheastern UniversityShenyang 110819LiaoningChina Shenyang Natural Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110116LiaoningChina

In the present work,we developed a micellar system of milk protein-surfactant(SDS)-graphene to prepare the graphene-based aerogels via hydrothermal and freeze-drying method,in which the novel surface-property of aerogels can be tuned with the decreasing of micellar size in the colloid systems resulting the improved specific surface *** milk protein also severed as green and sustainable sources to introduce nitrogen heteroatoms into the ***,the aerogels were further graphitized and activated to fabricate N-doped porous nanocarbon at 600℃.The initial surface composition and structure of the aerogel,which was proved,has obvious impact on the final structure of the synthesized nanocarbon materials,and thus influence their electrochemical *** optimized nanocarbon materials(MGPC-5),with enhanced specific surface area,degree of graphitization,and nitrogen doping,exhibited excellent capacitance performance and stability in both three-electrode system(518.8 F/g at a current density of 0.1 A/g)and symmetrical electrode system(120.8 F/g at current density of 0.1 A/g and with^95%capacitance retention after 5000 cycles of charging and discharging at 3 A/g)in *** assembled supercapacitor also shows ideal capacitive properties in series and parallel *** with a stable 1.6 V windows in Li2SO4 electrolyte,the symmetric supercapacitor cell exhibits a high energy density up to 36.7 W h/*** present work provides a feasible fabrication method for high-performance supercapacitor based on graphene and biomass derived carbon,the proposed surfaceproperty regulation and supercapacitor performance improvement strategy may also shed light on other energy related materials or system.

关键词： Graphene-based aerogel Milk protein Surfactant Controllable surface-property Supercapacitor

Superconductivity in potassium and ammonia co-intercalated FeSe_(1-x)Te_x

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Science China(Physics,Mechanics & Astronomy) 2019年第4期62卷 84-90页

作者： BinBin Xiao NaiZhou Wang Chao Shang fanbao meng JianWen Ding Bin Lei XiGang Luo Department of Physics and Institute for Nanophysics and Rare-earth Luminescence Xiangtan University College of Physics and Electronics Engineering Hengyang Normal University Hefei National Laboratory for Physical Science at Microscale and Department of Physics University of Science and Technology of China

The origin of the ～40 and ～30 K superconducting phases in the metal-intercalated FeSe superconductors is still unclear. We report the synthesis of K_(0.3)(NH_3)_y(FeSe_(1-x)Te_x)_2 and K_(0.6)(NH_3)_y(FeSe_(1-x)Te_x)_2 with x=0-0.6 by using the liquid ammonia method at room temperature. The superconducting transition temperature Tcof the former remains about 43 K for all the nominal Te content less than 0.3, while that of the latter is about 30 K and obviously decreases with Te doping. Superconductivity disappears for x ≥0.4 in both systems. Except for the different chemical pressure induced by substitution of Te for Se in both systems, we also observed distinct external pressure effect on superconductivity for both systems, with much more efficiency of suppressing Tcby external pressure in the former system. These dramatic differences of both chemical and external pressure effects on Tc between the ～30 and ～40 K superconducting phases revealed that the existence of the two superconducting phases can be ascribed to the moderate and negligible coupling between FeSe layers, respectively.

关键词： pnictides and chalcogenides properties of superconductors effects of pressure methods of materials synthesis and materials processing

Magnetic field-induced electronic phase transition in the Dirac semimetal state of black phosphorus under pressure

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Science Bulletin 2018年第23期63卷 1539-1544页

作者： Zeliang Sun Ziji Xiang Zhongyi Wang Jinglei Zhang Long Ma Naizhou Wang Chao Shang fanbao meng Liangjian Zou Yuanbo Zhang Xianhui Chen Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics and CAS Key Laboratory of Strongly-Coupled Quantum Matter PhysicsUniversity of Science and Technology of ChinaHefei 230026China Key Laboratory of Materials Physics Institute of Solid State PhysicsChinese Academy of SciencesHefei 230031China Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions and High Magnetic Field LaboratoryChinese Academy of SciencesHefei 230031China State Key Laboratory of Surface Physics and Department of Physics Fudan UniversityShanghai 200433China Collaborative Innovation Center of Advanced Microstructures Nanjing UniversityNanjing 210093China

Different instabilities have been confirmed to exist in the three-dimensional(3D) electron gas when it is confined to the lowest Landau level in the extreme quantum limit. The recently discovered 3D topological semimetals offer a good platform to explore these phenomena due to the small sizes of their Fermi pockets, which means the quantum limit can be achieved at relatively low magnetic fields. In this work, we report the high-magnetic-field transport properties of the Dirac semimetal state in pressurized black phosphorus. Under applied hydrostatic pressure, the band structure of black phosphorus goes through an insulator-semimetal transition. In the high pressure topological semimetal phase, anomalous behaviors are observed on both magnetoresistance and Hall resistivity beyond the relatively low quantum limit field, which is demonstrated to indicate the emergence of an exotic electronic state hosting a density wave ordering. Our findings bring the first insight into the electronic interactions in black phosphorus under intense field.

关键词： Black phosphorus High magnetic field Quantum limit Electron phase transition

Monitoring the Modal Frequency and Velocity Variations of Bridges under Ambient Excitation

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Earthquake Research in China 2015年第4期29卷 554-566页

作者： Chen Haichao Ge Hongkui meng fanbao Wang Xiaoqiong Yang Wei Unconventional Natural Gas Institute China University of Petroleum-Beijing Institute of Geophysics China Earthquake Administration

We conducted a long-term monitoring experiment on the Lutuanxilu Bridge located in Changping District of Beijing, employing our recently developed real-time bridge monitoring system based on the Guralp CMG-6TD broadband seismometer. We identified the modal parameters with the stochastic subspace identification( SSI) algorithm,and continuously monitored the temporal velocity variation with coda wave *** results show that:( 1) the highly sensitive Guralp CMG-6TD broadband seismometer,which records the three-component vibration signal within broad frequency range,is well suited for long-term bridge health monitoring.( 2) With the continuous vibration signal from ambient excitation,the stochastic subspace algorithm can robustly identify the low-order modal parameters and the coda wave interferometry can accurately monitor the tiny velocity variation.( 3) The elastic modulus of bridge materials changes significantly associated with varying temperature,leading to diurnal velocity variation with amplitude of approximately 1%. The velocity variation shows strong negative correlation with temperature fluctuation. Meanwhile,the modal frequencies remain quite stable,suggesting that the velocity variation may be a more sensitive quantitative damage index.( 4) While the modal frequencies reflect the integrated health status of the bridge,the velocity variation can be utilized to monitor the local elastic modulus. Therefore,it is crucial for bridge health monitoring to continuously monitor the two key damage indexes under ambient excitation.

关键词： Ambient excitation Stochastic subspace Identification Coda wave interferometry Modal frequency Velocity variation

Magnetic-field enhanced high-thermoelectric performance in topological Dirac semimetal Cd3As2 crystal

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Science Bulletin 2018年第7期63卷 411-418页

作者： Honghui Wang Xigang Luo Weiwei Chen Naizhou Wang Bin Lei fanbao meng Chao Shang Likuan Ma Tao Wu Xi Dai Zhengfei Wang Xianhui Chen Hefei National Laboratory for Physical Science at Microscale and Department of Physics University of Science and Technology of China and Key Laboratory of Strongly-coupled Quantum Matter Physics. Chinese Academy of Sciences Hefei 230026 China Physics Department Hong Kong University of Science and Technology Hang Kong China High Magnetic Field Laboratory of the Chinese Academy of Sciences Hefei 230031 China Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing 210093 China

Thermoelectric materials can be used to convert heat to electric power through the Seebeck effect. We study magneto-thermoelectric figure of merit （ZT） in three-dimensional Dirac semimetal Cd3A 5 2 crystal. It is found that enhancement of power factor and reduction of thermal conductivity can be realized at the same time through magnetic field although magnetoresistivity is greatly increased. ZT can be highly enhanced from 0.17 to 1.1 by more than six times around 350 K under a perpendicular magnetic field of 7 T. The huge enhancement of ZT by magnetic field arises from the linear Dirac band with large Fermi velocity and the large electric thermal conductivity in CdsA 5 2. Our work paves a new way to greatly enhance the thermoelectric performance in the quantum topological materials.

关键词： Dirac semimetal Thermoelectric material Magnetic field Enhancement of figure of merit

Electric-field-controlled superconductor–ferromagnetic insulator transition

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Science Bulletin 2019年第10期64卷 653-658页

作者： Likuan Ma Bin Lei Naizhou Wang Kaishuai Yang Dayong Liu fanbao meng Chao Shang Zeliang Sun Jianhua Cui Changsheng Zhu Tao Wu Zhe Sun Liangjian Zou Xianhui Chen Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics University of Science and Technology of China Hefei 230026 China Key Laboratory of Materials Physics Institute of Solid State Physics Chinese Academy of Sciences Hefei 230031 China CAS Center for Excellence in Quantum Information and Quantum Physics Hefei 230026 China Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing 210093 China National Synchrotron Radiation Laboratory University of Science and Technology of China Hefei 230026 China G4S Center for Excellence in Superconducting Electronics (CENSE) Shanghai 200050 China

Superconductivity beyond electron-phonon mechanism is always twisted with magnetism. Based on a new field-effect transistor with solid ion conductor as the gate dielectric(SIC-FET), we successfully achieve an electric-field-controlled phase transition between superconductor and ferromagnetic insulator in(Li,Fe)OHFeSe. A dome-shaped superconducting phase with optimal T_c of 43K is continuously tuned into a ferromagnetic insulating phase, which exhibits an electric-field-controlled quantum critical behavior. The origin of the ferromagnetism is ascribed to the order of the interstitial Fe ions expelled from the(Li,Fe)OH layers by gating-controlled Li injection. These surprising findings offer a unique platform to study the relationship between superconductivity and ferromagnetism in Fe-based superconductors. This work also demonstrates the superior performance of the SIC-FET in regulating physical properties of layered unconventional superconductors.

关键词： FeSe-based superconductors Ferromagnetic insulator Phase transition Solid ion conductor field-effect transistors (SIC-FET)

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同轴虚阴极振荡器微波输出模式

西南交通大学学报 2007年第2期42卷 186-189页

作者：罗雄廖成孟凡宝西南交通大学电磁场与微波技术研究所四川成都610031 中国工程物理研究院应用电子学研究所四川绵阳621900

为深入理解同轴虚阴极振荡器的工作原理,结合同轴虚阴极振荡器的实验结果,通过理论和数值模拟分析了同轴虚阴极振荡器微波输出模式．分析结果与在远场条件下的通过实验获得的天线辐射方向图对比．研究结果表明,同轴虚阴极振荡器输出微波... 详细信息

为深入理解同轴虚阴极振荡器的工作原理,结合同轴虚阴极振荡器的实验结果,通过理论和数值模拟分析了同轴虚阴极振荡器微波输出模式．分析结果与在远场条件下的通过实验获得的天线辐射方向图对比．研究结果表明,同轴虚阴极振荡器输出微波由TM01模式和TE11模式共同组成,其中TM01模式所占比例约为66％- 75％,TE11模式所占比例约为25％-34％．

关键词：高功率微波同轴虚阴极振荡器远场方向图微波输出模式