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Elasticity and Anisotropy of the Pyrite-Type FeO2H-FeO2 System in Earth’s Lowermost Mantle

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Journal of Earth Science 2019年第6期30卷 1293-1301页

作者： Shengxuan Huang Shan qin Xiang wu Key Laboratory of Orogenic Belts and Crustal Evolution MOESchool of Earth and Space SciencesPeking UniversityBeijing 100871China State Key Laboratory of Geological Processes and Mineral Resourses China University of GeosciencesWuhan 430074China

The pyrite-type FeO2 H-Fe O2 system has been experimentally confirmed to be stable in Earth's lowermost mantle but there is limited information about its physical properties at high pressures constraining our understanding of its potential geophysical implications for the deep ***,static calculations demonstrate that the pyrite-type FeO2 H-FeO2 system has a high density and Poisson's ratio and ultra-low seismic velocities at conditions of Earth's lowermost *** provides a plausible mechanism for the origin of ultra-low velocity zones at Earth's D″*** incorporation of hydrogen in the pyrite-type FeO2H-FeO2 system tends to decrease the S wave velocity(VS)but increase the bulk sound velocity(VΦ),and can potentially explain the observed anti-correlation of VS and VΦin the lowermost ***,FeO2 H exhibits nearly isotropic whereas Fe O2 is highly anisotropic,which may help understand some seismic anisotropies at the core-mantle boundary.

关键词： FeO2H FeO2 ultra-low velocity zones D″layer anisotropy

Selective substitution induced anomalous phonon stiffening within quasi-one-dimensional P–P chains in SiP2

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Nano Research 2023年第1期16卷 1107-1114页

作者： Xueting Dai Feng qin Caiyu Qiu Ling Zhou Junwei Huang Fanghua cheng Xiangyu Bi Caorong Zhang Zeya Li Ming Tang Shengqiang wu Xiaoxu Zhao yangfan Lu Huiyang Gou Hongtao Yuan National Laboratory of Solid State Microstructures Jiangsu Key Laboratory of Artificial Functional MaterialsCollege of Engineering and Applied Sciencesand Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210000China School of Materials Science and Engineering Peking UniversityBeijing 100871China College of Materials Science and Engineering National Engineering Research Center for Magnesium AlloysChongqing UniversityChongqing 400030China Center for High Pressure Science and Technology Advanced Research Beijing 100094China

Light-matter interactions in low-dimensional quantum-confined structures can dominate the optical properties of the materials and lead to optoelectronic *** anisotropic layered silicon diphosphide(SiP2)crystal,the embedded quasi-onedimensional(1D)phosphorus–phosphorus(P–P)chains directly result in an unconventional quasi-1D excitonic state,and a special phonon mode vibrating along the P–P chains,establishing a unique 1D quantum-confined *** SiP2 with the homologous element serves as an effective way to study the properties of these excitons and phonons associated with the quasi-1D P–P chains,as well as the strong interaction between these ***,the experimental observation and the related optical spectral understanding of SiP2 with isoelectronic dopants remain ***,with the photoluminescence and Raman spectroscopy measurements,we demonstrate the redshift of the confined excitonic peak and the stiffening of the phonon vibration mode■of a series of Si(P1−xAsx)2 alloys with increasing arsenic(As)*** anomalous stiffening of■is attributed to the selective substitution of As atoms for P atoms within the P–P chains,which is confirmed via our scanning transmission electron microscopy *** optical spectra evolutions with selective substitution pave a new way to understand the 1D quantum confinement in semiconductors,offering opportunities to explore quasi-1D characteristics in SiP2 and the resulting photonic device application.

关键词： SiP2 quasi-one-dimensional structure Raman photoluminescence phosphide

Investigation into high-pressure behavior of MnTiO_3:X-ray diffraction and Raman spectroscopy with diamond anvil cells

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Geoscience Frontiers 2011年第1期2卷 107-114页

作者： Xiang wu Shan qin Leonid Dubrovinsky Key Laboratory of Orogenic Belts and Crustal Evolution MOE ＆ School of Earth and Space Sciences Peking University Beijing 100871 China Bayerisches Geoinstitut Universita＇t Bayreuth Bayreuth D-95440 Germany

The structural stability of manganese titanate MnTiO3 at high pressure was investigated by X-ray diffraction and Raman spectroscopy with diamond anvil cells. Ilmenite-type MnTiO3 is stable at least to 26.6 GPa, and lithium niobate type MnTiO3 reversibly transforms at room temperature to perovskite at 2.0 GPa. Bulk moduli （K300） of ilmenite, lithium niobate and perovskite are 174（4） GPa, 179 （8） GPa, and 208（5） GPa, respectively （at fixed first pressure derivative K＇ = 4）. The Griineisen parameter T has been estimated to be 1.28 for ilmenite and 1.75 for perovskite. In ilmenite phase, TiO6 octahedra become more regular with increasing pressure. In perovskite phase structural distortion increases with pressure increase.

关键词： MnTiO3 Ilmenite Lithium niobate Perovskite Phase transition Equation of state

Thermally stable Ir/Ce0.9La0.1O2 catalyst for high temperature methane dry reforming reaction

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Nano Research 2017年第2期10卷 364-380页

作者： Fagen Wang Leilei Xu Weidong Shi Jian Zhang Kai wu Yu Zhao Hui Li He Xing Li Guo qin Xu Wei Chen Laboratory of Energy and Environment Interface Engineering National University of Singapore Suzhou Research Institute Suzhou 215123 China School of Chemistry and Chemical Engineering Jiangsu University Zhenjiang 212013 China School of Environmental Science and Engineering Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Collaborative Innovation Center of the Atmospheric Environment and Equipment Technology Nanjing University of Information Science & Technology Nanjing 210044 China department of Chemistry National University of Singapore 3 Science Drive 3 Singapore 117543 Singapore College of Chemistry and Molecular Engineering Peking University Beijing 100871 China department of Chemistry Shanghai Normal University Shanghai 200234 China Singapore-peking university Research Center for a Sustainable Low-Carbon Future I CREATE Way # 15-01 CREATE Tower Singapore 138602 Singapore

In this study, the use of a thermally stable Ir/Ce0.9La0.1O2 catalyst was investigated for the dry reforming of methane. The doping of La203 into the CeO2 lattice enhanced the chemical and physical properties of the Ir/Ce0.9La0.1O2 catalyst, such as redox properties, Ir dispersion, oxygen storage capacity, and thermal stability, with respect to the Ir/CeO2 catalyst. Hence, the Ir/Ce0.9La0.1O2 catalyst exhibits higher activity and stabler performance for the dry reforming of methane than the Ir/CeO2 catalyst. This observation can be mainly attributed to the stronger interaction between the metal and support in the Ir/Ce0.9La0.1O2 catalyst stabilizing the catalyst structure and improving the oxygen storage capacity, leading to negligible aggregation of Ir nanoparticles and the Ce0.9La0.1O2 support at high temperatures, as well as the rapid removal of carbon deposits at the boundaries between the Ir metal and the Ce0.9La0.1O2 support.

关键词： thermally stable catalyst Ir/Ce0.9La0.1O2 metal-support interaction methane dry reforming

Synthesis of Finite Molecular Nanotubes by Connecting Axially Functionalized Macrocycles

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CCS Chemistry 2022年第12期4卷 3772-3780页

作者： Liang-Liang Mao Hongyan Xiao Jin-qin Zhao Zhuo Diao Wen Zhou Hongwei Li Chen-Ho Tung Li-Zhu wu Huan Cong Key Laboratory of Photochemical Conversion and Optoelectronic Materials Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190 Key Laboratory of Bio-Inspired Materials and Interfacial Science Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190 School of Future Technology University of Chinese Academy of SciencesBeijing 100049 beijing National Laboratory for Molecular Sciences College of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871 beijing NMR Center Peking UniversityBeijing 100871

Monodispersed molecular nanotubes,particularly those with uniform lengths,are challenging targets for chemical ***,we report the general design and efficient synthesis of finite molecular nanotubes,utilizing a dynamic assembly strategy to precisely stack axially functionalized macrocycles by chemical *** tubular molecules,ranging from 7.8 to 19.8 kDa with covalent or coordinative connections,have been prepared from modular macrocyclic building blocks through highly convergent *** discrete molecular nature and structural anisotropy of these synthetic tubes warrant postsynthesis modifications and solution processing methods,as demonstrated by the controllable orientations when deposited onto different prefabricated surfaces.

关键词： molecular nanotube dynamic assembly macrocycle covalence coordination

Evidence for particle acceleration approaching PeV energies in the W51 complex

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Science Bulletin 2024年第18期69卷 2833-2841页

作者： LHAASO Collaboration Zhen Cao F.Aharonian Axikegu Y.X.Bai Y.W.Bao D.Bastieri X.J.Bi Y.J.Bi W.Bian A.V.Bukevich Q.Cao W.Y.Cao Zhe Cao J.Chang J.F.Chang A.M.Chen E.S.Chen H.X.Chen Liang Chen Lin Chen Long Chen M.J.Chen M.L.Chen Q.H.Chen S.Chen S.H.Chen S.Z.Chen T.L.Chen Y.Chen N.cheng Y.D.cheng M.Y.Cui S.W.Cui X.H.Cui Y.D.Cui B.Z.Dai H.L.Dai Z.G.Dai Danzengluobu X.Q.Dong K.K.Duan J.H.Fan Y.Z.Fan J.Fang J.H.Fang K.Fang C.F.Feng H.Feng L.Feng S.H.Feng X.T.Feng Y.Feng Y.L.Feng S.Gabici B.Gao C.D.Gao Q.Gao W.Gao W.K.Gao M.M.Ge L.S.Geng G.Giacinti G.H.Gong Q.B.Gou M.H.Gu F.L.Guo X.L.Guo Y.Q.Guo Y.Y.Guo Y.A.Han M.Hasan H.H.He H.N.He J.Y.He Y.He Y.K.Hor B.W.Hou C.Hou X.Hou H.B.Hu Q.Hu S.C.Hu D.H.Huang T.Q.Huang W.J.Huang X.T.Huang X.Y.Huang Y.Huang X.L.Ji H.Y.Jia K.Jia K.Jiang X.W.Jiang Z.J.Jiang M.Jin M.M.Kang I.Karpikov D.Kuleshov K.Kurinov B.B.Li C.M.Li cheng Li Cong Li D.Li F.Li H.B.Li H.C.Li Jian Li Jie Li K.Li S.D.Li W.L.Li W.L.Li X.R.Li Xin Li Y.Z.Li Zhe Li Zhuo Li E.W.Liang Y.F.Liang S.J.Lin B.Liu C.Liu D.Liu D.B.Liu H.Liu H.D.Liu J.Liu J.L.Liu M.Y.Liu R.Y.Liu S.M.Liu W.Liu Y.Liu Y.N.Liu Q.Luo Y.Luo H.K.Lv B.Q.Ma L.L.Ma X.H.Ma J.R.Mao Z.Min W.Mitthumsiri H.J.Mu Y.C.Nan A.Neronov L.J.Ou P.Pattarakijwanich Z.Y.Pei J.C.Qi M.Y.Qi B.Q.Qiao J.J.qin A.Raza D.Ruffolo A.Sáiz M.Saeed D.Semikoz L.Shao O.Shchegolev X.D.Sheng F.W.Shu H.C.Song Yu.V.Stenkin V.Stepanov Y.Su D.X.Sun Q.N.Sun X.N.Sun Z.B.Sun J.Takata P.H.T.Tam Q.W.Tang R.Tang Z.B.Tang W.W.Tian C.Wang C.B.Wang G.W.Wang H.G.Wang H.H.Wang J.C.Wang Kai Wang Kai Wang L.P.Wang L.Y.Wang P.H.Wang R.Wang W.Wang X.G.Wang X.Y.Wang Y.Wang Y.D.Wang Y.J.Wang Z.H.Wang Z.X.Wang Zhen Wang Zheng Wang D.M.Wei J.J.Wei Y.J.Wei T.Wen C.Y.wu H.R.wu Q.W.wu S.wu X.F.wu Y.S.wu S.Q.Xi J.Xia G.M.Xiang D.X.Xiao G.Xiao Y.L.Xin Y.Xing D.R.Xiong Z.Xiong D.L.Xu R.F.Xu R.X.Xu W.L.Xu L.Xue D.H.Yan J.Z.Yan T.Yan C.W.yang C.Y.yang F.yang F.F.yang L.L.yang M.J.yang R.Z.yang W.X.yang Y.H.Yao Z.G.Yao L.Q.Yin N.Yin X.H.You Z.Y.You Y.H.Yu Q.Yuan H.Yue H.D.Zeng T.X.Zeng W.Zeng M.Zha B.B.Zhang F.Zhang H.Zhang 不详 Key Laboratory of Particle Astrophysics&Experimental Physics Division&Computing Center Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China university of Chinese Academy of Sciences Beijing 100049China TIANFU Cosmic Ray Research Center ChengduChina Dublin Institute for Advanced Studies 31 Fitzwilliam Place2 DublinIreland Max-Planck-Institut for Nuclear Physics P.O.Box 103980Heidelberg 69029Germany School of Physical Science and Technology&School of Information Science and Technology Southwest Jiaotong UniversityChengdu 610031China School of Astronomy and Space Science Nanjing UniversityNanjing 210023China Center for Astrophysics Guangzhou UniversityGuangzhou 510006China Tsung-Dao Lee Institute&School of Physics and Astronomy Shanghai Jiao Tong UniversityShanghai 200240China Institute for Nuclear Research of Russian Academy of Sciences Moscow 117312Russia Hebei Normal university Shijiazhuang 050024China university of Science and Technology of china Hefei 230026China State Key Laboratory of Particle Detection and Electronics China Key Laboratory of Dark Matter and Space Astronomy&Key Laboratory of Radio Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China Research Center for Astronomical Computing Zhejiang LaboratoryHangzhou 311121China Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical ObservatoryChinese Academy of SciencesShanghai 200030China School of Physics and Astronomy Yunnan UniversityKunming 650091China Key Laboratory of Cosmic Rays(Tibet university) Ministry of EducationLhasa 850000China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China School of Physics and Astronomy(Zhuhai)&School of Physics(Guangzhou)&Sino-French Institute of Nuclear Engineering and Technology(Zhuhai) Sun Yat-sen UniversityZhuhai 519000&Guangzhou 510275GuangdongChina Institute of Frontier and Interdisciplinary Science Shandong UniversityQingdao 266237China APC UniversitéParis Cité

Theγ-ray emission from the W51 complex is widely acknowledged to be attributed to the interaction between the cosmic rays(CRs)accelerated by the shock of supernova remnant(SNR)W51C and the dense molecular clouds in the adjacent star-forming region,***,the maximum acceleration capability of W51C for CRs remains *** on observations conducted with the Large High Altitude Air Shower Observatory(LHAASO),we report a significant detection ofγrays emanating from the W51 complex,with energies from 2 to 200 *** LHAASO measurements,for the first time,extend theγ-ray emission from the W51 complex beyond 100 TeV and reveal a significant spectrum bending at tens of *** combining the"π^(0)-decay bump"featured data from Fermi-LAT,the broadbandγ-ray spectrum of the W51 region can be well-characterized by a simple pp-collision *** observed spectral bending feature suggests an exponential cutoff at~400 TeV or a power-law break at~200 TeV in the CR proton spectrum,most likely providing the first evidence of SNRs serving as CR accelerators approaching the PeV ***,two young star clusters within W51B could also be theoretically viable to produce the most energeticγrays observed by *** findings strongly support the presence of extreme CR accelerators within the W51 complex and provide new insights into the origin of Galactic CRs.

关键词： UHE c-ray Cosmic rays SNR W51C Star clusters

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中国政府网“一带一路”新闻话题挖掘分析

图书情报工作 2019年第15期63卷 103-110页

作者：秦玥吴亚平王继民北京大学信息管理系北京100871 北京大学图书馆北京100871

[目的/意义]探究中国政府网"一带一路"相关新闻的话题内容及热度变化,呈现"一带一路"倡议主题及动态,明确不同时期的倡议重点,为相关研究提供参考。[方法/过程]构建基于LDA模型的新闻话题内容的基本框架,限定2015-2017年"一带一路"相关... 详细信息

[目的/意义]探究中国政府网"一带一路"相关新闻的话题内容及热度变化,呈现"一带一路"倡议主题及动态,明确不同时期的倡议重点,为相关研究提供参考。[方法/过程]构建基于LDA模型的新闻话题内容的基本框架,限定2015-2017年"一带一路"相关新闻数据,利用LDA模型进行话题抽取,根据文档与话题的概率分布计算,分析各主题在不同时间段的热度演化。[结果/结论]抽取得出30个细分话题,归纳为政策沟通、设施联通、贸易畅通、资金融通、民心相通、"一带一路"对我国经济的影响和政府工作7大类。其中,政策沟通类在全时间段上热度最高,贸易畅通和"一带一路"对我国经济的影响两类话题紧随其后。"进出口"等细分话题的热度不断上升,"改革与转型"等细分话题的热度则有下降,体现了官方媒体新闻内容及其关注度随时间而变化的特点。

关键词： “一带一路” LDA模型话题抽取热度演化