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domain-engineered BiFeO3 thin-film photoanodes for highly enhanced ferroelectric solar water splitting

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Nano Research 2018年第2期11卷 642-655页

作者： Jaesun Song Taemin Ludvic Kim Jongmin Lee Sam Yeon Cho Jaeseong Cha Sang Yun Jeong Hyunji An Wan Sik Kim Yen-Sook Jung Jiyoon Park Gun Young Jung Dong-Yu Kim Ji Young Jo Sang Don Bu Ho Won Jang Sanghan Lee School of Materials Science and Engineering Gwangju Institute of Science and Technology (GIST) Gwangju Republic of Korea Department of Materials Science and Engineering Research Institute of Advanced Materials Seoul National University Seoul Republic of Korea Department of Physics Chonbuk National University Jeonju Republic of Korea

In photoelectrochemical （PEC） water splitting, charge separation and collection by the electric field in the photoactive material are the most important factors for improved conversion efficiency. Hence, ferroelectric oxides, in which electrons are the majority carriers, are considered promising photoanode materials because their high built-in potential, provided by their spontaneous polarization, can signifi＇canfly enhance the separation and drift of photogenerated carriers. In this regard, the PEC properties of BiFeO3 thin-film photoanodes with different crystallographic orientations and consequent ferroelectric domain structures are investigated. As the crystallographic orientation changes from （001）pc via （ll0）pc to （lll）p~, the ferroelastic domains in epitaxial BiFeO3 thin films become mono-variant and the spontaneous polarization levels increase to 110 btC/cm2. Consequent136 the photocurrent density at 0 V vs. Ag/AgC1 increases approximately 5.3-fold and the onset potential decreases by 0.180 V in the downward polarization state. It is further demonstrated that ferroelectric switching in the （lll）pc BiFeO3 thin-film photoanode leads to an approximate change of 8,000% in the photocurrent density and a 0.330 V shift in the onset potential. This study strongly suggests that domain-engineered ferroelectric materials can be used as effective charge separation and collection layers for efficient solar water-splitting photoanodes.

关键词： BiFeO3 ferroelectric photoelectrochemical domain orientation pulsed laser deposition

domain structure and defects of highly ordered Bi_4Si_3O_(12) micro-crystals

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Science China(Technological Sciences) 2009年第8期52卷 2295-2301页

作者： TIAN QingQuan, WANG XiuFeng, YU ChengLong, JIANG HongTao, ZHANG ZhengGuang, WANG Yan & LIN SheBao School of Materials Science and Engineering, Shaanxi University of Science & Technology, Xi’an 710021, China School of Materials Science and Engineering Shaanxi University of Science & Technology Xi’an 710021 China

Highly ordered Bi4Si3O12 micro-crystals were prepared at normal atmosphere. Phase identification of the prepared crystals was accomplished by X-ray diffractometer (XRD). domain structure and defects were characterized by environmental scanning electron microscopy (ESEM). XRD shows that the obtained micro-crystals are of eulytite structure with chemical formulation of Bi4Si3O12. A highly ordered growth pattern is confirmed due to the faster growth of the {124} faces than that of the {204} faces by ESEM. The growing process of the domain structure is of pollen parent and filial generation pattern. The filial generations of Bi4Si3O12 crystals are generated from the pollen parent. Cracks generate from the defect areas and propagate along the {124} faces due to their lower binding energy under a proper temperature gradient, contributing to the total transcrystalline fracture. It is confirmed that the generation and development of the voids in the crystal grains can be developed when unmatched dimensions of the two opposite faces are formed. And the development of the voids is dependent on the dimensions and orientations of the two opposite faces.

关键词： crystal growth domain structure Bi4Si3O12 highly ordered structure eulytite

domain Structures in Minerals

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Science China Chemistry 1993年第8期36卷 1019-1024,1026页

作者：徐惠芳徐洪武罗谷风 Department of Earth Sciences Nanjing University Nanjing 210008 PRC Department of Silicate Engineering Nanjing Institute of Chemical Technology Nanjing 210009 PRC

domain structures in mineral crystals could be categorized into three groups and several subgroups within each group, based on characteristics of domain structures and mechanisms causing domain structures: (ⅰ) domain structures constituted by domains with the same (or identical) crystal structure and chemical composition, including anti-phase domain structures, twinning domain structures, inversion domain structures, and translationtwinning domain structures; (ⅱ) domain structures constituted by two or more than two kinds of domains with the same chemical composition but different crystal structures; and (ⅲ) domain structures constituted by two kinds of compositional and structural different domains, including exsolution-induced and polysomatic reaction-induced domain structures. Different types of domain structures may display different phenomena in their TEM images and SAED patterns, due to different crystallographic characteristics of different domain structures. The domain structures in minerals may affect physical properties, chemical composition, and thermodynamic properties of minerals, and can also indicate the evolution history of minerals.

关键词： mineral domain structure transmission electron microscopic image electron diffraction pattern.

Detecting Fake News Over Online Social Media via domain Reputations and Content Understanding

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Tsinghua Science and Technology 2020年第1期25卷 20-27页

作者： Kuai Xu Feng Wang Haiyan Wang Bo Yang School of Mathematical and Natural Sciences Arizona State UniversityGlendaleAZ 85306USA Jiangxi University of Finance and Economics Nanchang 330013China

Fake news has recently leveraged the power and scale of online social media to effectively spread misinformation which not only erodes the trust of people on traditional presses and journalisms, but also manipulates the opinions and sentiments of the public. Detecting fake news is a daunting challenge due to subtle difference between real and fake news. As a first step of fighting with fake news, this paper characterizes hundreds of popular fake and real news measured by shares, reactions, and comments on Facebook from two perspectives:domain reputations and content understanding. Our domain reputation analysis reveals that the Web sites of the fake and real news publishers exhibit diverse registration behaviors, registration timing, domain rankings, and domain popularity. In addition, fake news tends to disappear from the Web after a certain amount of time. The content characterizations on the fake and real news corpus suggest that simply applying term frequency-inverse document frequency(tf-idf) and Latent Dirichlet Allocation(LDA) topic modeling is inefficient in detecting fake news,while exploring document similarity with the term and word vectors is a very promising direction for predicting fake and real news. To the best of our knowledge, this is the first effort to systematically study domain reputations and content characteristics of fake and real news, which will provide key insights for effectively detecting fake news on social media.

关键词： social media fake news detection content modeling domain reputations

Characteristic signal extracted from a continuous time signal on the aspect of frequency domain

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Chinese Physics B 2019年第9期28卷 124-130页

作者： Zhi-Fan Du Rui-Hao Zhang Hong Chen College of Electronic Engineering Heilongjiang University

Extracting characteristic signal from a continuous signal can effectively reduce the difficulty of analyzing the running states of a single-variable nonlinear *** the extracted characteristic signal can accurately reflect the running states of the system is very *** this paper, a method called automatic sampling method(ASM) for extracting characteristic signals is *** complete definition is described, the effectiveness is proved theoretically, and the general formulas of the extracted characteristic signals are derived for the first ***, typical Chua's circuit is used to accomplish a lot of experimental research on the aspect of frequency *** experimental results show that ASM is feasible and practical, and can automatically generate a characteristic signal with the change of the original signal.

关键词： automatic sampling method characteristic signal frequency domain system states

A modified domain reduction method for numerical simulation of wave propagation in localized regions

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Earthquake Engineering and Engineering Vibration 2019年第1期18卷 35-52页

作者： Luo Chao Lou Menglin Gui Guoqing Wang Hao School of Civil Engineering Shijiazhuang Tiedao University Cooperative Innovation Center of Disaster Prevention and Mitigation for Large Infrastructure in Hebei province (Shijiazhuang Tiedao University) State Key Laboratory of Disaster Reduction in Civil Engineering Tongji University School of Architecture and Civil Engineering Jinggangshan University

A modified domain reduction method(MDRM) that introduces damping terms to the original DRM is presented in this paper. To verify the proposed MDRM and compare the computational accuracy of these two methods, a numerical test is designed. The numerical results of the MDRM and DRM are compared using an extended meshed model. The results show that the MDRM significantly improved the computational accuracy of the DRM. Then, the MDRM is compared with two existing conventional methods, namely Liao's transmitting boundary and viscous-spring boundary with Liu's method. The MDRM shows its great advancement in computational accuracy, stability and range of applications. This paper also discusses the influence of boundary location on computational accuracy. It can be concluded that smaller models tend to have larger errors. By introducing two dimensionless parameters, φ_1 and φ_2, the rational distance between the observation point and the MDRM boundary is suggested. When φ_1 >2 or φ_2>13, the relative PGA error can be limited to 5%. In practice, the appropriate model size can be chosen based on these two parameters to achieve desired computational accuracy.

关键词： modified domain reduction method domain reduction method viscous boundary viscous spring boundary transmitting boundary wave propagation

Optimum lateral extent of soil domain for dynamic SSI analysis of RC framed buildings on pile foundations

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Frontiers of Structural and Civil Engineering 2020年第1期14卷 62-81页

作者： Nishant SHARMA Kaustubh DASGUPTA Arindam DEY Department of Civil Engineering Indian Institute of Technology GuwahatiGuwahati 781039India

This article describes a novel approach for deciding optimal horizontal extent of soil domain to be used for finite element based numerical dynamic soil structure interaction(SSI)*** model for a 12 storied building frame,supported on pile foundation-soil system,is developed in the finite element based software framework,*** different structure-foundation configurations are analyzed under different ground motion *** extent of soil domain,along with the soil properties,were varied exhaustively for a particular structural *** on the reduction in the variation of acceleration response at different locations in the SSI system(quantified by normalized root mean square error,NRMSE),the optimum lateral extent of the soil domain is prescribed for various structural widths,soil types and peak ground acceleration levels of ground *** to the past studies,error estimation analysis shows that the relationships prescribed in the present study are credible and more inclusive of the various factors that influence *** relationships can be readily applied for deciding upon the lateral extent of the soil domain for conducting precise SSI analysis with reduced computational time.

关键词： soil structure interaction optimum lateral extent of soil domain length multi-storyed framed building pile foundation OpenSEES L-K boundaries dynamic analysis

Optimized dithering technique in frequency domain for high-quality three-dimensional depth data acquisition

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Chinese Physics B 2019年第8期28卷 124-131页

作者： Ning Cai Zhe-Bo Chen Xiang-Qun Cao Bin Lin State Key Laboratory of Modern Optical Instrumentation CNERC for Optical InstrumentsZhejiang UniversityHangzhou 310027China Research Institute of Zhejiang University-Taizhou Taizhou 318000China

On the basis of the objective functions,dithering optimization techniques can be divided into the intensity-based optimization technique and the phase-based optimization ***,both types of techniques are spatial-domain optimization techniques,while their measurement performances are essentially determined by the harmonic components in the frequency *** this paper,a novel genetic optimization technique in the frequency domain is proposed for highquality fringe *** addition,to handle the time-consuming difficulty of genetic algorithm(GA),we first optimize a binary patch,then join the optimal binary patches together according to periodicity and symmetry so as to generate a full-size *** is verified that the proposed technique can significantly enhance the measured performance and ensure the robustness to various amounts of defocusing.

关键词： fringe generation genetic algorithm frequency domain 3D shape measurement

A time domain three-dimensional sono-elastic method for ships' vibration and acoustic radiation analysis in water

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Journal of Hydrodynamics 2019年第3期31卷 542-551页

作者： Ming-song Zou You-sheng Wu Can Sima Shu-xiao Liu China Ship Scientific Research Center Wuxi 214082 China State Key Laboratory of Deep-sea Manned Vehicles Wuxi 214082 China National Key Laboratory on Ship Vibration and Noise Wuxi 214082 China

The classical three-dimensional hydroelasticity of ships is extend to include the effect of fluid compressibility, which yields the three-dimensional sono-elasticity of ships. To enable the predictions of coupled transient or nonlinear vibrations and acoustic radiations of ship structures, a time domain three-dimensional sono-elastic analysis method of acoustic responses of a floating structure is presented. The frequency domain added mass and radiation damping coefficients of the ship are first calculated by a three-dimensional frequency domain analysis method, from which a retardation function is derived and converted into the generalized time domain radiation force through a convolution integral. On this basis the generalized time domain sono-elastic equations of motion of the ship hull in water are established for calculation of the steady-state or transient-state excitation induced coupled vibrations and acoustic radiations of the ship. The generalized hydrodynamic coefficients, structural vibrations and underwater acoustic radiations of an elastic spherical shell excited by a concentrated pulsating force are illustrated and compared with analytical solutions with good agreement. The numerical results of a rectangular floating body are also presented to discuss the numerical error resultant from truncation of the upper integration limit in the Fourier integral of the frequency domain added mass coefficients for the retardation function.

关键词： Hydroelasticity sono-elasticity time domain Fourier transform vibration acoustic radiation