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Seismogenesis and occurrence of earthquakes as observed by temporally continuous gravity variations in China

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Chinese Science Bulletin 1998年第1期43卷 8-21页

作者： Gongxu Gu John t. Kuo keren Liu Jinhan Zheng Hongyan Lu Duanfa Liu State Seismol Bur Inst Geophys Beijing 100081 Peoples R China Columbia Univ Lamont Doherty Earth Observ New York NY 10027 USA Columbia Univ Aldridge Lab Appl Geophys New York NY 10027 USA

In the last decade and a half, a number of earthquakes of magnitude 4-5 have occurred in the Beijing_tianjin_tangshan_Zhangjiakou (BttZ) region. On the basis of the analysis of the temporally continuous gravity variation data principally from the Baijiatuan (BJtN) semi_permanent gravity base station, a general picture of gravity variation related to the seismogenesis and occurrence of earthquakes has emerged.\;As gravity variation is generally observed on the earth’s surface, the predominant influence is that of the near_surface groundwater. the subsurface fluids are distributed throughout all depths in the crust and respond to the seismogenic processes of earthquakes as well. the influence of the subsurface fluid on gravity variation is, therefore, of equal importance. the fluids, which include the near_surface groundwater and the subsurface fluids distributed throughout all depths in the crust, play a more important role in the gravity variations in terms of the seismogenesis and occurrence of earthquakes than previously realized.\;the abundance of accumulated data shows that the dilatancy instability (IPE) model seems not applicable at least to the seismogenesis and occurrence of earthquakes in the BttZ region. In order to reflect the physical reality, the earlier proposed combined dilatancy model requires modification. the seismogenic area in the BttZ region may be modelled as a large pre_stressed volume of a fluid_filled poroelastic medium, including not only the pre_stressed volume surrounding the impending rupture zone but also the volume containing the rupture of the fault zone itself. the pre_stressed volume outside the impending rupture zone is under a state of relatively small change of the pre_existing regional tectonic stress, while the volume containing the impending rupture zone is an induced region of very high local stress concentration, and/or pore over_pressure.\;the calculated gravity variations based on the modified combined dilatancy model (MCD

关键词： gravity variations earthquake groundwater subsurface fluids.

Carbon nanosheets derived from reconstructed lignin for potassium and sodium storage with low voltage hysteresis

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Nano Research 2021年第12期14卷 4664-4673页

作者： keren Jiang Xuehai tan Shengli Zhai Ken Cadien Zhi Li Department of Chemical and Materials Engineering University of AlbertaEdmontonAlbertaT6G 1H9Canada

Lignin is the second most abundant and the only nature polymer rich in aromatic *** aromatic-unit-rich precursors often yield soft carbon after carbonization,the side chains in lignin crosslink with the aromatic units and form a rigid three-dimensional(3D)structure which eventually leads to hard *** a graphene oxide-catalyzed decomposition and repolymerization process,we successfully reconstructed lignin by partially tailoring the side *** to directly carbonized lignin,the carbonized reconstructed lignin possesses significantly fewer defects,86%fewer oxygen-functionalities,82%fewer micropores,and narrower interlayer *** parameters can be tuned by the amount of catalysts(graphene oxide).When tested as anode for K-ion and Na-ion batteries,the carbonized reconstructed lignin delivers notably higher capacity at low-potential range(especially for Na-storage),shows much-improved performance at high current density,and most importantly,reduces voltage hysteresis between discharge and charge process by more than 50%,which is critical to the energy efficiency of the energy storage *** study reveals that the voltage hysteresis in K-storage is much severer than that in Na-storage for all *** practical K-ion battery applications,the voltage hysteresis deserves more attention in future electrode materials design and the reconstruct ion strategy introduced in this work provides potential low-cost solution.

关键词： lignin batteries polarization voltage hysteresis ring-forming defects

Simultaneous manipulations of thermal expansion and conductivity in symbiotic SctaO_(4)/SmtaO_(4) composites via multiscale effects

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Journal of Advanced Ceramics 2023年第8期12卷 1625-1640页

作者： Lin Chen Jiankun Wang Baihui Li keren Luo Jing Feng Faculty of Materials Science and Engineering Kunming University of Science and TechnologyKunming 650093China

Effective manipulations of thermal expansion and conductivity are significant for improving operational performances of protective coatings,thermoelectric,and *** work uncovers determinant mechanisms of the thermal expansion and conductivity of symbiotic SctaO_(4)/SmtaO_(4) composites as thermal/environmental barrier coatings(t/EBCs),and we consider the effects of interface stress and thermal *** weak bonding and interface stress among composite grains manipulate coefficient of thermal expansion(CtE)stretching from 6.4×10^(−6) to 10.7×10^(−6) K^(−1) at 1300℃,which gets close to that of substrates in t/EBC *** multiscale effects,including phonon scattering at the interface,mitigation of the phonon speed(vp),and lattice point defects,synergistically depress phonon thermal transports,and we estimate the proportions of different *** interface thermal resistance(R)reduces the thermal conductivity(k)by depressing phonon speed and scattering phonons because of different acoustic properties and weak bonding between symbiotic SctaO_(4) and SmtaO_(4) ceramics in the *** study proves that CtE of tantalates can be artificially regulated to match those of different substrates to expand their applications,and the uncovered multiscale effects can be used to manipulate thermal transports of various materials.

关键词： thermal management coefficient of thermal expansion(CtE) interface thermal resistance(R) thermal stress(σ) thermal/environmental barrier coatings(t/EBCs)

Light field salient object detection:A review and benchmark

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Computational Visual Media 2022年第4期8卷 509-534页

作者： keren Fu Yao Jiang Ge-Peng Ji tao Zhou Qijun Zhao Deng-Ping Fan College of Computer Science Sichuan Universityand National Key Laboratory of Fundamental Science on Synthetic VisionSichuan UniversityChengdu 610065China School of Computer Science Wuhan UniversityWuhan 430072China PCA Lab School of Computer Science and EngineeringNanjing University of Science and TechnologyNanjing 210094China Computer Vision Lab ETH ZürichZürichSwitzerland

Salient object detection(SOD)is a long-standing research topic in computer vision with increasing interest in the past *** light fields record comprehensive information of natural scenes that benefit SOD in a number of ways,using light field inputs to improve saliency detection over conventional RGB inputs is an emerging *** paper provides the first comprehensive review and a benchmark for light field SOD,which has long been lacking in the saliency ***,we introduce light fields,including theory and data forms,and then review existing studies on light field SOD,covering ten traditional models,seven deep learning-based models,a comparative study,and a brief *** datasets for light field SOD are also ***,we benchmark nine representative light field SOD models together with several cutting-edge RGB-D SOD models on four widely used light field datasets,providing insightful discussions and analyses,including a comparison between light field SOD and RGB-D SOD *** to the inconsistency of current datasets,we further generate complete data and supplement focal stacks,depth maps,and multi-view images for them,making them consistent and *** supplemental data make a universal benchmark ***,light field SOD is a specialised problem,because of its diverse data representations and high dependency on acquisition hardware,so it differs greatly from other saliency detection *** provide nine observations on challenges and future directions,and outline several open *** the materials including models,datasets,benchmarking results,and supplemented light field datasets are publicly available at https://***/kerenfu/LFSOD-Survey.

关键词： light field salient object detection(SOD) deep learning benchmarking

Freestanding hierarchical porous carbon film derived from hybrid nanocellulose for high-power supercapacitors

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Nano Research 2017年第5期10卷 1847-1860页

作者： Zhi Li Kaveh Ahadi keren Jiang Behzad Ahvazi Peng Li Anthony O. Anyia Ken Cadien thomas thundat Chemical and Materials Engineering University of Alberta Edmonton Alberta T6G 2V4 Canada Biomass Conversion & Processing technologies Innotech Alberta Innovates-Technology Futures Edmonton Alberta T6N 1E4 Canada nanoFAB University of Alberta Edmonton Alberta T6G 2V4 Canada National Research Council of Canada 100 Sussex Drive Ottawa Ontario K1A OR6 Canada

Nanocellulose is a sustainable and eco-friendly nanomaterial derived from renewable biomass. In this study, we utilized the structural advantages of two types of nanocellulose and fabricated freestanding carbonized hybrid nanocellulose films as electrode materials for supercapacitors. the long cellulose nanofibrils （CNFs） formed a macroporous framework, and the short cellulose nanocrystals were assembled around the CNF framework and generated micro/mesopores. this two-level hierarchical porous structure was successfully preserved during carbonization because of a thin atomic layer deposited （ALD） A1203 conformal coating, which effectively prevented the aggregation of nanocellulose. these carbonized, partially graphitized nanocellulose fibers were interconnected, forming an integrated and highly conductive network with a large specific surface area of 1,244 m2·g-1. the two-level hierarchical porous structure facilitated fast ion transport in the film. When tested as an electrode material with a high mass loading of 4 mg·cm-2 for supercapacitors, the hierarchical porous carbon film derived from hybrid nanocellulose exhibited a specific capacitance of 170 F·g-1 and extraordinary performance at high current densities. Even at a very high current of 50 A-g-l, it retained 65% of its original specific capacitance, which makes it a promising electrode material for high-power applications.

关键词： nanocellulose supercapacitors hierarchical structure atomic layer deposition(ALD) integrated structure

Quantum state and process tomography via adaptive measurements

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Science China(Physics,Mechanics & Astronomy) 2016年第10期59卷 25-32页

作者： HengYan Wang WenQiang Zheng NengKun Yu keren Li DaWei Lu tao Xin Carson Li ZhengFeng Ji David Kribs Bei Zeng XinHua Peng JiangFeng Du Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics University of Science and Technology of ChinaHefei 230026China Department of Applied Physics Zhejiang University of TechnologyHangzhou 310023China Institute for Quantum Computing University of WaterlooWaterloo N2L 3G1Canada 4Department of Mathematics&Statistics University of GuelphGuelph N1G 2W1Canada Centre for Quantum Computation&Intelligent Systems Faculty of Engineering and Information TechnologyUniversity of Technology SydneySydney NSW 2007Australia State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics Tsinghua UniversityBeijing 100084China Department of Physics University of GuelphGuelph N1G 2W1Canada State Key Laboratory of Computer Science Institute of SoftwareChinese Academy of SciencesBeijing 100190China Canadian Institute for Advanced Research Toronto M5G 1Z8Canada

We investigate quantum state tomography(QSt) for pure states and quantum process tomography(QPt) for unitary channels via adaptive measurements. For a quantum system with a d-dimensional Hilbert space, we first propose an adaptive protocol where only 2d. 1 measurement outcomes are used to accomplish the QSt for all pure states. this idea is then extended to study QPt for unitary channels, where an adaptive unitary process tomography(AUPt) protocol of d2+d.1measurement outcomes is constructed for any unitary channel. We experimentally implement the AUPt protocol in a 2-qubit nuclear magnetic resonance system. We examine the performance of the AUPt protocol when applied to Hadamard gate, t gate(/8 phase gate), and controlled-NOt gate,respectively, as these gates form the universal gate set for quantum information processing purpose. As a comparison, standard QPt is also implemented for each gate. Our experimental results show that the AUPt protocol that reconstructing unitary channels via adaptive measurements significantly reduce the number of experiments required by standard QPt without considerable loss of fidelity.

关键词： quantum tomography state reconstruction nuclear magnetic resonance

Single-base resolution mapping of 2′-O-methylation sites by an exoribonuclease-enriched chemical method

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Science China(Life Sciences) 2023年第4期66卷 800-818页

作者： Ping Zhang Junhong Huang Wujian Zheng Lifan Chen Shurong Liu Anrui Liu Jiayi Ye Jie Zhou Zhirong Chen Qiaojuan Huang Shun Liu keren Zhou Lianghu Qu Bin Li Jianhua Yang MOE Key Laboratory of Gene Function and Regulation State Key Laboratory of BiocontrolSchool of Life SciencesThe Fifth Affiliated HospitalSun Yat-sen UniversityGuangzhou 510275China Department of Chemistry The University of ChicagoChicagoIL 60637USA Department of Systems Biology Beckman Research Institute of City of HopeMonroviaCA 91016USA

2′-O-methylation(Nm)is one of the most abundant RNA epigenetic modifications and plays a vital role in the post-transcriptional regulation of gene *** Nm mapping approaches are normally limited to highly abundant RNAs and have significant technical hurdles in m RNAs or relatively rare non-coding RNAs(nc RNAs).Here,we developed a new method for enriching Nm sites by using RNA exoribonuclease and periodate oxidation reactivity to eliminate 2′-hydroxylated(2′-OH)nucleosides,coupled with sequencing(Nm-REP-seq).We revealed several novel classes of Nm-containing nc RNAs as well as m RNAs in humans,mice,and *** found that some novel Nm sites are present at fixed positions in different t RNAs and are potential substrates of fibrillarin(FBL)methyltransferase mediated by sno ***,we discovered,for the first time,that Nm located at the 3′-end of various types of nc RNAs and fragments derived from *** approach precisely redefines the genome-wide distribution of Nm and provides new technologies for functional studies of Nm-mediated gene regulation.

关键词： 2′-O-methylation MgR exoribonuclease periodate oxidation epitranscriptome transcriptome

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Hilbert-Huang变换在非线性超声无损检测中的应用

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清华大学学报（自然科学版） 2006年第8期46卷 1369-1372页

作者：陈斌杨平施克仁清华大学机械工程系北京100084

为了提高非线性超声无损检测方法对缺陷位置和相对大小的表征能力,该文将H ilbert-Huang变换方法用于非线性超声无损检测信号的处理。粗晶奥氏体不锈钢材料的非线性超声无损检测信号具有非线性、非稳态和低信噪比的特性,H ilbert-Huang... 详细信息

为了提高非线性超声无损检测方法对缺陷位置和相对大小的表征能力,该文将H ilbert-Huang变换方法用于非线性超声无损检测信号的处理。粗晶奥氏体不锈钢材料的非线性超声无损检测信号具有非线性、非稳态和低信噪比的特性,H ilbert-Huang变换对此类信号的特征提取具有独特的优势。实验结果表明:通过H ilbert-Huang变换的瞬时频率能够确定缺陷位置,瞬时幅度可表征缺陷的相对大小;该方法达到了对0.6mm晶粒平均直径的粗晶奥氏体不锈钢中65 mm深、0.8 mm平底孔的小缺陷检出能力,说明H ilbert-Huang变换有效提高了非线性超声无损检测的缺陷表征能力。

关键词：无损检测非线性超声 Hilbert—Huang变换粗晶材料

StRONG DERIVAtIVE AND ItS CONSEQUENCES

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Journal of Mathematical Study 1994年第1期 191-193页

作者： Yang keren Lu Shipan(Jimei teachers CollegeXiamen 361021)

ＳＴＲＯＮＧＤＥＲＩＶＡＴＩＶＥＡＮＤＩＴＳＣＯＮＳＥＱＵＥＮＣＥＳ￥ＹａｎｇＫｅｒｅｎ；ＬｕＳｈｉｐａｎ（ＪｉｍｅｉＴｅａｃｈｅｒｓＣｏｌｌｅｇｅＸｉａｍｅｎ３６１０２１）Ａｂｓｔｒａｃｔ：Ｗｅｉｎｔｒｏｄｕｃｅｓ... 详细信息

ＳＴＲＯＮＧＤＥＲＩＶＡＴＩＶＥＡＮＤＩＴＳＣＯＮＳＥＱＵＥＮＣＥＳ￥ＹａｎｇＫｅｒｅｎ；ＬｕＳｈｉｐａｎ（ＪｉｍｅｉＴｅａｃｈｅｒｓＣｏｌｌｅｇｅＸｉａｍｅｎ３６１０２１）Ａｂｓｔｒａｃｔ：Ｗｅｉｎｔｒｏｄｕｃｅｓｔｒｏｎｇｄｅｒｉｖａｔｉｖｅ，ｔ...

关键词： strong derivative Z-integral Z’-integral Riemann integral Lebesgue integral.