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Linear dichroism and polarization controllable persistent spin helix in two-dimensional ferroelectric ZrOI_(2) monolayer

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Nano Research 2022年第7期15卷 6779-6789页

作者： Niuzhuang Yang Gaoyang Gou Xiaoli Lu Yue Hao School of Microelectronics State Key Discipline Laboratory of Wide Bandgap Semiconductor TechnologyXidian UniversityXi’an 710071China Frontier Institute of science and Technology Xi’an Jiaotong UniversityXi’an 710049China Collaborative Innovation center of Quantum information of Shaanxi Province Xidian UniversityXi’an 710071China

Two-dimensional ferroelectric(2D-FE)materials that characterize the spontaneous ferroelectricity down to monolayer limit and rich ferroic properties arising from FE orderings,have been extensively explored as low-dimensional sensor,electric and memory *** current work,group-IV transition metal oxide dihalide MOX_(2)(M=Zr and Hf,X=Cl,Br and I)monolayers have been identified as a new group of 2D-FE *** the comprehensive first-principles calculations combined with finite temperature Monte Carlo(MC)and ab initio molecular dynamics(MD)simulations,we investigate the temperature stability of FE polarization and further uncover the unique properties associated with spontaneous ferroelectricity of MOX_(2) *** particular,ZrOI_(2) monolayer,a promising 2D-FE material with room temperature stable ferroelectricity,semiconducting electronic structure and optoelectronic response under visible light,offers an ideal material platform to investigate the coupling of intrinsic anisotropy,optical absorption selectivity and spin degree of freedom with 2D ***,significant optical absorption anisotropy and giant linear dichroism effect are predicted for a 2D optical polarizer device based on ZrOI_(2) monolayer,where the adsorption of incident monochromatic linearly polarized light(hv=3.23 eV)along two planar directions with a nearly 100%optical selectivity can be ***,the spin–orbit coupling(SOC)induced spin splitting of valence band edges and out-of-plane textured spin configuration occur in ZrOI_(2) *** the meanwhile,the unidirectional spin–orbit field protected by C2v wave-vector point group can further create the persistent spin helix(PSH)state,leading to the extraordinarily long spin carrier *** importantly,the nonvolatile control of PSH state via the electric field induced polarization reversal has also been demonstrated for FE-ZrOI_(2) monolayer,which manifests as a great advantage for applications of

关键词： two-dimensional ferroelectricity first-principles calculations optical absorption anisotropy spin-textured ferroelectrics allelectric spintronics

Enhanced removal of I^- on hierarchically structured layered double hydroxides by in suit growth of Cu/Cu2O

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Journal of Environmental sciences 2020年第2期32卷 338-348页

作者： Jiuyu Chen Junyi Wang Qianhong Gao Xiaomei Zhang Ying Liu Peng Wang Yan Jiao Zongxiang Zhang Yi Yang Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse School of Environmental and Biological EngineeringNanjing University of Science and TechnologyNanjing 210094China Collaborative Innovation center of Atmospheric Environment and Equipment Technology Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control(AEMPC)Nanjing University of Information Science&TechnologyNanjing 210044China Jiangsu Environmental Protection Key Laboratory of Monitoring for Organic Pollutants in Soil Taizhou Environmental Monitoring CenterTaizhou 225300China

To further improve the removal ability of layered double hydroxide(LDH) for iodide(I^-) anions from wastewater, we prepared hierarchically porous Cu5Mg10Al5-LDH and used as a matrix for in suit growth of Cu/Cu2O on its surface, forming Cu/Cu2O-LDH, which was characterized and applied as an *** displayed high I^-saturation uptake capability(137.8 mg/g) of Cu/Cu2O-LDH compared with Cu5Mg10Al5-LDH(26.4 mg/g) even thermal activated LDH(76.1 mg/g).Thermodynamic analysis showed that the reaction between I^-anions and Cu/Cu2O-LDH is a spontaneous and *** kinetics analysis exhibited that adsorption equilibrium can be reached after 265 ***, the adsorbent showed satisfactory selectivity in the presence of competitive anions(e.g., SO4^2-), and could achieve good adsorption performance in a wide pH range of 3–8.A cooperative adsorption mechanism was proposed on the basis of the following two aspects:(1) ion exchange between iodide and interlayer anions;(2) the adsorption performance of Cu, Cu(Ⅱ) and Cu2O for I^-.Meanwhile, the difference between the adsorption mechanism of Cu/Cu2O-LDH, Cu5Mg10Al5-LDH and Cu5Mg10Al5-CLDH adsorbents was also elaborated and verified.

关键词： Layered double hydroxide Cu/Cu2O Iodide adsorption Hierarchical structure In suit growth

Geospatial assessment of rooftop solar photovoltaic potential using multi-source remote sensing data

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Energy and AI 2022年第4期10卷 17-28页

作者： Hou Jiang Ling Yao Ning Lu Jun Qin Tang Liu Yujun Liu Chenghu Zhou Institute of Geographic sciences and Natural Resources Research Chinese Academy of SciencesBeijing100101China Southern Marine science and Engineering Guangdong Laboratory Guangzhou 511458China Jiangsu center for Collaborative Innovation in Geographical information Resource Development and Application Nanjing Normal UniversityNanjing 210023China School of information Engineering China University of Geosciences(Beijing)Beijing100083China Provincial Geomatics center of Jiangsu Nanjing210013China

Rooftop solar photovoltaics (PV) play increasing role in the global sustainable energy transition. This raises the challenge of accurate and high-resolution geospatial assessment of PV technical potential in policymaking and power system planning. To address the challenge, we propose a general framework that combines multi-resource satellite images and deep learning models to provide estimates of rooftop PV power generation. We apply deep learning based inversion model to estimate hourly solar radiation based on geostationary satellite images, and automatic segmentation model to extract building footprint from high-resolution satellite images. The framework enables precise survey of available rooftop resources and detailed simulation of power generation on an hourly basis with a spatial resolution of 100 m. The case study in Jiangsu Province demonstrates that the framework is applicable for large areas and scalable between precise locations and arbitrary regions across multiple temporal scales. Our estimates show that rooftop resources across the province have a potential installed capacity of 245.17 GW, corresponding to an annual power generation of 290.66 TWh. This highlights the huge space for carbon emissions reduction through developing rooftop PVs.

关键词： Rooftop photovoltaics Building footprints Remote sensing Deep learning Solar energy

Evaluation of Ordinary Least Square(OLS) and Geographically Weighted Regression(GWR) for Water Quality Monitoring:A Case Study for the Estimation of Salinity

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Journal of Ocean University of China 2018年第2期17卷 305-310页

作者： NAZEER Majid BILAL Muhammad Earth & Atmospheric Remote Sensing Laboratory (EARL) Department of Meteorology COMSATS Institute of Information Technology School of Marine sciences Nanjing University of Information Science and Technology Department of Land Surveying and Geo-Informatics The Hong Kong Polytechnic University

Landsat-5 Thematic Mapper(TM) dataset have been used to estimate salinity in the coastal area of Hong Kong. Four adjacent Landsat TM images were used in this study, which was atmospherically corrected using the Second Simulation of the Satellite Signal in the Solar Spectrum(6S) radiative transfer code. The atmospherically corrected images were further used to develop models for salinity using Ordinary Least Square(OLS) regression and Geographically Weighted Regression(GWR) based on in situ data of October 2009. Results show that the coefficient of determination(R^2) of 0.42 between the OLS estimated and in situ measured salinity is much lower than that of the GWR model, which is two times higher(R^2 = 0.86). It indicates that the GWR model has more ability than the OLS regression model to predict salinity and show its spatial heterogeneity better. It was observed that the salinity was high in Deep Bay(north-western part of Hong Kong) which might be due to the industrial waste disposal, whereas the salinity was estimated to be constant(32 practical salinity units) towards the open sea.

关键词： Landsat Thematic Mapper water quality salinity remote sensing coastal water

Compact diffraction grating laser wavemeter for cold atom experiments

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Optoelectronics Letters 2017年第5期13卷 335-338页

作者：魏春华颜树华张甜 Department of Instrument science and Technology College of Mechatronic Engineering and Automation National University of Defense Technology Interdisciplinary center for Quantum information National University of Defense Technology Xi'an Aerospace Huaxun Technology Co. LTD.

We present an innovative and practical scheme of building a miniaturized wavemeter, with the advantages of low cost, high reliability and simple structure. Through a calibration test by a 780 nm external cavity diode laser(ECDL), the results show that our system gets a wavelength resolution of better than 1 pm, measurement accuracy of better than 2 pm(corresponding to a frequency of 1 GHz), and a measurement range of 8.5 nm. Finally, the multi-mode comparison test between our system and a commercial spectrum analyzer further indicates the high-precision, miniaturization and low cost of the proposed system, which shows that it is particularly suitable for ECDL and atom cooling and trapping experiments. The system design, experimental results and conclusions are of definite significance as a fine reference for other ranges of wavelength.

关键词： Calibration Spectrum analyzers Wavemeters

An efficient bi-objective optimization framework for statistical chip-level yield analysis under parameter variations

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Frontiers of information Technology & Electronic Engineering 2016年第2期17卷 160-172页

作者： Xin LI Jin SUN Fu XIAO Jiang-shan TIAN Technology Innovation center Jiangsu Academy of Safety Science and Technology Jiangsu High Technology Research Key Laboratory for Wireless Sensor Networks Nanjing University of Posts and Telecommunications School of Computer science and Engineering Nanjing University of Science and Technology

With shrinking technology,the increase in variability of process,voltage,and temperature(PVT) parameters significantly impacts the yield analysis and optimization for chip *** yield estimation algorithms have been limited to predicting either timing or power ***,neglecting the correlation between power and delay will result in significant yield *** of these approaches also suffer from high computational complexity and long *** suggest a novel bi-objective optimization framework based on Chebyshev affine arithmetic(CAA) and the adaptive weighted sum(AWS) *** power and timing yield are set as objective functions in this *** two objectives are optimized simultaneously to maintain the correlation between *** proposed method first predicts the guaranteed probability bounds for leakage and delay distributions under the assumption of arbitrary *** a power-delay bi-objective optimization model is formulated by computation of cumulative distribution function(CDF) ***,the AWS method is applied for power-delay optimization to generate a well-distributed set of Pareto-optimal *** results on ISCAS benchmark circuits show that the proposed bi-objective framework is capable of providing sufficient trade-off information between power and timing yield.

关键词： Parameter variations Parametric yield Multi-objective optimization Chebyshev affine Adaptive weighted sum

Tunable Multicolor Fluorescence of Perovskite-Based Composites for Optical Steganography and Light-Emitting Devices

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Research 2023年第1期2022卷 185-195页

作者： Kewei Ma Qingfeng Gui Cihui Liu Yunyi Yang Fangjian Xing Yunsong Di Xiaoming Wen Baohua Jia Zhixing Gan center for Future Optoelectronic Functional Materials School of Computer and Electronic Information/School of Artificial IntelligenceNanjing Normal UniversityNanjing 210023China College of Naval Architecture and Ocean Engineering Jiangsu Maritime InstituteNanjing 211170China Centrefor Translational Atomaterials Schoolof ScienceSwinburne University of TechnologyJohn Street Hawthon VIC3122Australia School of science RMIT UniversityMelbourne3000 VICAustralia College of Materials science and Engineering Qingdao University of Science and TechnologyQingdao 266042China

Multicolor fluorescence of mixed halide perovskites enormously enables their applications in photonics and ***,it remains an arduous task to obtain multicolor emissions from perovskites containing single halogen to avoid phase ***,a fluorescent composite containing Eu-based metal-organic frameworks(MOFs),OD Cs PbBre,and 3D CsPbBrs is *** excitations at 365 nm and 254nm,the pristine composite emits blue(B)and red(R)fluorescence,which are ascribed to radiative defects within CsPbBr and 5Do→7F,transitions of Eu^(3+),***,after light soaking in the ambient environment,the blue fluorescence gradually converts into green(G)emission due to the defect repairing and 0D-3D phase *** permanent and unique photochromic effect enables anticounterfeiting and microsteganography with increased security through a micropatterning ***,the RGB luminescence is highly stable after encapsulation by a transparent polymer ***,trichromatic light-emitting modules are fabricated by using the fluorescent composites as color-converting layers,which almost fully cover the standard color ***,this work innovates a strategy for construction of tunable multicolor luminescence by manipulating the radiative defects and structural dimensionality.

关键词： composite composites perovskite

Contrasting room-temperature hydrogen sensing capabilities of Pt-SnO2 and Pt-TiO2 composite nanoceramics

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Nano Research 2016年第11期9卷 3528-3535页

作者： Yao Xiong Wanping Chen Yesheng Li Ping Cui Shishang Guo Wei Chen Zilong Tang Zijie Yan Zhenyu Zhang School of Physics and Technology Wuhan University Wuhan 430072 China School of Materials science and Engineering State Key Laboratory of New Ceramics and Fine Processing Tsinghua University Beijing 100084 China International center for Quantum Design of Functional Materials (ICQD) Hefei Laboratory for Physical Sciences at Microscale (HFNL) and Synergetic Innovation Center of Notional Quantum Information and Quantum Physics University of Science and Technology of China Hefei 230026 China Department of Chemical and Biomolecular Engineering Clarkson University Potsdam New York 13699 USA

Contrasting room-temperature hydrogen sensing behaviors have been revealed for Pt-TiO2 and Pt-SnO2 composite nanoceramics. In the case of the Pt-TiO2 nanoceramics, the ultrahigh hydrogen sensitivities are lost abruptly when the oxygen/hydrogen concentration ratio in ambient atmosphere reaches a critical value. However, in the case of the Pt-SnO2 nanoceramics, such a phenomenon does not occur, and the extraordinary room-temperature hydrogen sensing capabilities are observed in the presence of oxygen in air. Our combined experimental and theoretical investigations establish a unified mechanism for both the systems, which is rooted in hydrogen chemisorption on the surface and interstitial lattice sites of SnO2 and TiO2; the difference in stability of the chemisorbed hydrogen on SnO2 and TiO2 is considered responsible for the contrasting hydrogen sensing capabilities. The central findings are helpful in enriching our microscopic understanding of hydrogen interaction with various metal oxide semiconductors （MOSs） at room temperature in varying mixed gaseous concentrations, and they could be instrumental in developing reliable room-temperature hydrogen sensors based on bulk MOSs.

关键词： Sn02 nanoceramics sensors hydrogen room-temperature

Chirp-Rate Resolution of Fractional Fourier Transform in Multi-component LFM Signal

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Journal of Beijing Institute of Technology 2009年第1期18卷 74-78页

作者：刘锋黄宇陶然王越 School of information science and Technology Beijing Institute of Technology Department of Electronic Engineering Naval Aeronautical Engineering Institute

Distinguishing close chirp-rates of different linear frequency modulation （LFM） signals under concentrated and complicated signal environment was studied. Firstly, detection and parameter estimation of multi-component LFM signal were used by discrete fast fractional Fourier transform （FrFT）. Then the expression of chirp-rate resolution in fractional Fourier domain （FrFD） was deduced from discrete normalize time-frequency distribution, when multi-component LFM signal had only one center frequency. Furthermore, the detail influence of the sampling time, sampling frequency and chirp-rate upon the resolution was analyzed by partial differential equation. Simulation results and analysis indicate that increasing the sampling time can enhance the resolution, but the influence of the sampling frequency can he omitted. What＇s more, in multi-component LFM signal, the chirp-rate resolution of FrFT is no less than a minimal value, and it mainly dependent on the biggest value of chirp-rates, with which it has an approximately positive exponential relationship.

关键词： fractional Fourier transform(FrFT) resolution linear frequency modulation(LFM) signal chirp-rate