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Full-frame Data Reduction Method:A Data Mining Tool to Detect the Potential Variations in Optical Photometry

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Research in Astronomy and Astrophysics 2023年第5期23卷 110-141页

作者： Zhi-Bin dai Hao Zhou Jin cao Yunnan Observatories Chinese Academy of SciencesKunming 650216China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China Center for Astronomical Mega-Science Chinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 101408China School of Information Science and Engineering of Yunnan University Kunming 650500China

A Synchronous Photometry Data Extraction(SPDE)program,performing indiscriminate monitoring of all stars appearing in the same field of view of an astronomical image,is developed by integrating several Astropy affiliated packages to make full use of time series observed by traditional small/medium aperture ground-based *** complete full-frame stellar photometry data reductions implemented for the two time series of cataclysmic variables:RX J2102.0+3359 and Paloma J0524+4244 produce 363 and 641 optimal light curves,respectively.A cross-identification with SIMBAD finds 23 known stars,of which 16 are red giant-/horizontal-branch stars,2 W UMa-type eclipsing variables,2 program stars,an X-ray source and 2 Asteroid Terrestrial-impact Last Alert System *** on the data products from the SPDE program,a follow-up light curve analysis program identifies 32 potential variable light curves,of which 18 are from the time series of RX J2102.0+3359,and 14 are from that of Paloma J0524+*** are preliminarily separated into periodic,transient,and peculiar *** querying for the 58 VizieR online data catalogs,their physical parameters and multi-band brightness spanning X-ray to radio are compiled for future analysis.

关键词： catalogs-stars fundamental parameters-stars variables general-methods data analysis-techniques photometric

Meteorological influences on co-occurrence of O_(3) and PM_(2.5)pollution and implication for emission reductions in Beijing-Tianjin-Hebei

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Science China Earth Sciences 2023年第6期66卷 1258-1267页

作者： Xiaoqing MA Zhicong yin Bufan cao Huijun WANG Key Laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environment Change(ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)Nanjing University of Information Science&TechnologyNanjing 210044China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519080China Nansen-Zhu International Research Centre Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

Co-occurrence of surface ozone(O_(3))and fine particulate matter(PM_(2.5))pollution(CP)was frequently observed in Beijing-Tianjin-Hebei(BTH).More than 50%of CP days occurred during April-May in BTH,and the CP days reached up to 11 in two months of *** PM_(2.5)or O_(3) concentration associated with CP was lower than but close to that in O_(3) and PM_(2.5)pollution,indicating compound harms during CP days with double-high concentrations of PM_(2.5)and O_(3).CP days were significantly facilitated by joint effects of the Rossby wave train that consisted of two centers associated with the Scandinavia pattern and one center over North China as well as a hot,wet,and stagnant environmental condition in *** 2018,the number of CP days decreased sharply while the meteorological conditions did not change ***,changes in meteorological conditions did not really contribute to the decline of CP days in 2019 and *** implies that the reduction of PM_(2.5)emission has resulted in a reduction of CP days(about 11 days in 2019 and 2020).The differences in atmospheric conditions revealed here were helpful to forecast the types of air pollution on a daily to weekly time *** reduction in PM_(2.5)emission was the main driving factor behind the absence of CP days in 2020,but the control of surface O_(3) must be stricter and deeper.

关键词： Co-occurrence pollution Ozone PM_(2.5) Meteorology Emission reduction

Spectral Method for Nonlinear Stochastic Partial Differential Equations of Elliptic Type

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Numerical Mathematics(Theory,Methods and Applications) 2011年第1期4卷 38-52页

作者： Yanzhao cao Li yin Department of Mathematics Auburn UniversityAuburnAL 36849USA LCP Institute of Applied Physics and Computational MathematicsBeijing 100088China

This paper is concerned with the numerical approximations of semi-linear stochastic partial differential equations of elliptic type in ***gence analysis and error estimates are presented for the numerical solutions b... 详细信息

关键词： Stochastic differential equation spectral method error estimates white noise

Induced circularly polarized luminescence of perovskite nanocrystals by self-assembly chiral gel

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Nano Research 2023年第1期16卷 1459-1464页

作者： Rui cao Xuekang Yang Yong Wang yin Xiao School of Science Tianjin UniversityTianjin 300350China School of Chemical Engineering and Technology Tianjin UniversityTianjin 300350China National Center for Nanoscience and Technology Beijing 100190China

Perovskites nanocrystals(NCs)with circularly polarized light(CPL)activity have drawn much attention due to the fascinating photoelectric properties of perovskite NCs as well as the abundant applications of CPL in three-dimensional(3D)displays,nonlinear optics,spintronics devices,CPL lasers,and so ***,bio-inspired by life,we designed and synthesized a simple amphiphilic molecule which could self-assemble into chiral gel with helix chirality in non-polar *** co-assembly of the CsPbX3 NCs with the chiral gel,CPL at the first excitation band of CsPbX3 NCs is induced in the whole visible spectrum with a maximum glum of 8.2×10−*** induced CPL arises from the selective CPL-absorption of the CsPbX3 NCs’luminesce by the chiral gel,which provides a facile and practical approach to induce CPL in perovskite NCs and other nanocrystals.

关键词： circularly polarized light(CPL) chiral gel CsPbX3 perovskite nanocrystal selective CPL-absorption

Multi-band microwave photonic satellite repeater scheme employing intensity Mach-Zehnder modulators

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The Journal of China Universities of Posts and Telecommunications 2017年第2期24卷 89-95页

作者： yin Jie Dong Tao Zhang Bin Hao Yan cao Guixing Cheng Zijing Xu Kun Zhou Yue dai Jian Beijing Institute of Satellite Information Engineering State Key Laboratory of Space-Ground Integrated Information Technology Space Star Technology Company Limited Institute of Telecommunication Satellite China Academy of Space Technology State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications

To solve the satellite repeater＇s flexible and wideband frequency conversion problem, we propose a novel microwave photonic repeater system, which can convert the upload signal＇s carrier to six different frequencies. The scheme employs one 20 GHz bandwidth dual-drive Mach-Zehnder modulator （MZM） and two 10 GHz bandwidth MZMs. The basic principle of this scheme is filtering out two optical sidebands after the optical carrier suppression （OCS） modulation and combining two sidebands modulated by the input radio frequency （RF） signal. This structure can realize simultaneous multi-band frequency conversion with only one frequency-fixed microwave source and prevent generating harmful interference sidebands by using two corresponding optical filters after optical modulation. In the simulation, one C-band signal of 6 GHz carrier can be successfully converted to 12 GHz （Ku-band）, 28 GHz, 34 GHz, 40 GHz, 46 GHz （Ka-band） and 52 GHz （V-band）, which can be an attractive method to realize multi-band microwave photonic satellite repeater. Alternatively, the scheme can be configured to generate multi-band local oscillators （LOs） for widely satellite onboard clock distribution when the input RF signal is replaced by the internal clock source.

关键词： fiber optics and optical communication radio frequency photonics microwave photonics

Mn-doping induced electronic modulation and rich oxygen vacancies on vertically grown NiFe2O4 nanosheet array for synergistically triggering oxygen evolution reaction

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Nano Research 2022年第5期15卷 3940-3945页

作者： Yonghao Gan Meilin Cui Xiaoping dai ying Ye Fei Nie Ziteng Ren Xueli yin Baoqiang Wu Yihua cao Run Cai Xin Zhang State Key Laboratory of Heavy Oil Processing College of Chemical Engineering and EnvironmentChina University of PetroleumBeijing 102249China

Large-scale electrolysis of water to produce high-purity hydrogen is one of the effective ways to solve the energy crisis and environmental pollution ***,efficient,cheap and stable catalysts are one of the bottlenecks for industrial application in water ***,a facile one-step hydrothermal process was applied to fabricate Mn-doped nickel ferrite nanosheets(Mn-NiFe_(2)O_(4))which shown a low overpotential of 200 mV at 50 mA·cm^(-2)and a small Tafel slope of 47 mV·dec^(-1),together with a prominent turnover frequency(TOF)value(0.14 s^(-1))and robust *** in-situ UV-vis spectroscopy unveiled the surface reconstruction to generate NiOOH as active sites during oxygen evolution reaction(OER).The excellent electrocatalytic activity of Mn-NiFe_(2)O_(4)is attributed to the vertically grown nanosheets for exposure more active sites,rich oxygen vacancies,and the hybridization between Ni 3d and O 2p orbitals caused by Mn *** work should provide a facile strategy by Mn-doping to simultaneously engineer oxygen vacancies and electronic structure for synergistically triggering oxygen evolution reaction.

关键词： Mn doping NiFe_(2)O_(4)nanosheets oxygen vacancies electronic modulation oxygen evolution reaction

Generation and Photocatalytic Activities of Bi@Bi2O3 Microspheres

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Nano Research 2011年第5期4卷 470-482页

作者： Xiangwen Liu Huaqiang cao Jiefu yin Department of Chemistry Tsinghua University Beijing 100084 China

Composite Bi@Bi2O3 microspheres have been synthesized via a microwave-assisted solvothermal route. The Bi@Bi2O3 microspheres had a narrow size distribution in the range 1.2-2.8 mm. Glucose was selected as the reductant, BiCl3 as the bismuth source, and ethylene glycol （EG） as the solvent in the synthesis system. The as-synthesized sample was characterized by X-ray diffraction （XRD）, Raman spectroscopy, X-ray photoelectron spectroscopy （XPS）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, particle diameter distribution, energy dispersive X-ray spectroscopy （EDS）, ultraviolet-visible （UV-vis） spectroscopy, and photoluminescence （PL） spectroscopy. The photocatalytic activities of the Bi@Bi2O3 microspheres were evaluated by the photodegradation of rhodamine B （RhB） and methyl orange （MO） dyes under UV light irradiation. The degradation reached -96.6% for RhB and 100% for MO after 4 h reaction in the presence of the as-synthesized Bi@Bi2O3 microspheres.

关键词： Bismuth bismuth oxide photocatalysis microspheres solvothermal method

Establishment of human cerebral organoid systems to model early neural development and assess the central neurotoxicity of environmental toxins

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Neural Regeneration Research 2025年第1期20卷 242-252页

作者： daiyu Hu Yuanqing cao Chenglin Cai Guangming Wang Min Zhou Luying Peng Yantao Fan Qiong Lai Zhengliang Gao Fundamental Research Center Shanghai Yangzhi Rehabilitation Hospital(Shanghai Sunshine Rehabilitation Center)School of MedicineTongji UniversityShanghaiChina Institute of Geriatrics(Shanghai University) Affiliated Nantong Hospital of Shanghai University(The Sixth People’s Hospital of Nantong)Shanghai University School of MedicineNantongJiangsu ProvinceChina Shanghai Engineering Research Center of Organ Repair Shanghai University School of MedicineShanghaiChina Key Laboratory of Arrhythmias Ministry of EducationShanghai East HospitalSchool of MedicineTongji UniversityShanghaiChina

Human brain development is a complex process,and animal models often have significant *** address this,researchers have developed pluripotent stem cell-derived three-dimensional structures,known as brain-like organoids,to more accurately model early human brain development and *** enable more consistent and intuitive reproduction of early brain development,in this study,we incorporated forebrain organoid culture technology into the traditional unguided method of brain organoid *** involved embedding organoids in matrigel for only 7 days during the rapid expansion phase of the neural epithelium and then removing them from the matrigel for further cultivation,resulting in a new type of human brain organoid *** cerebral organoid system replicated the temporospatial characteristics of early human brain development,including neuroepithelium derivation,neural progenitor cell production and maintenance,neuron differentiation and migration,and cortical layer patterning and formation,providing more consistent and reproducible organoids for developmental modeling and toxicology *** a proof of concept,we applied the heavy metal cadmium to this newly improved organoid system to test whether it could be used to evaluate the neurotoxicity of environmental *** organoids exposed to cadmium for 7 or 14 days manifested severe damage and abnormalities in their neurodevelopmental patterns,including bursts of cortical cell death and premature *** exposure caused progressive depletion of neural progenitor cells and loss of organoid integrity,accompanied by compensatory cell proliferation at ectopic *** convenience,flexibility,and controllability of this newly developed organoid platform make it a powerful and affordable alternative to animal models for use in neurodevelopmental,neurological,and neurotoxicological studies.

关键词： cadmium cell death cell proliferation cortical development environmental toxins neural progenitor cells neurogenesis neurotoxicology organoids stem cells

On Weyl’s Theorem for Functions of Operators

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Acta Mathematica Sinica,English Series 2019年第8期35卷 1367-1376页

作者： Jiong DONG Xiao Hong cao Lei dai School of Mathematics and Information Science Shaanxi Normal University Xi'an 710119 P. R. China College of Mathematics and Physics Weinan Normal University Weinan 714000 P. R. China

Let H be a complex separable infinite dimensional Hilbert space. In this paper, a variant of the Weyl spectrum is discussed. Using the new spectrum, we characterize the necessary and sufficient conditions for both T and f(T) satisfying Weyl’s theorem, where f ∈ Hol(σ(T)) and Hol(σ(T)) is defined by the set of all functions f which are analytic on a neighbourhood of σ(T) and are not constant on any component of σ(T). Also we consider the perturbations of Weyl’s theorem for f(T).

关键词： Spectrum Weyl's theorem functions of operators compact perturbation