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Decomposing the host galaxy from high-z QSOs using principal component analysis

Research in Astronomy and Astrophysics 2019年第10期19卷 17-26页

作者： Wei He Yi-Ping Wang National Astronomical Observatories Chinese Academy of Sciences Beijing 100101 China school of Astronomy and Space Science University of Chinese Academy of Sciences Beijing 100049 China

High resolution deep imaging from space and adaptive optics techniques with large ground-based facilities have enabled studies examining faint host galaxies of high redshift quasi-stellar objects (QSOs). However, the related image processing techniques, especially for a precise point-spread function (PSF) reconstruction and characterization of the host galaxy light profiles, have yet to be optimized. We present here the scientific performance of a principal component analysis (PCA) based PSF subtraction of the central bright point source of high redshift QSO images, as well as further characterization of the host galaxy profile by directly fitting a Sèrsic model to the residual image using the Markov Chain Monte Carlo (MCMC) algorithm. With a set of reference PSF star images which represent interleaving exposures between the QSO imaging, we can create an orthogonal basis of eigen-images and restore the PSF of QSO images by projecting the QSO images onto the basis. In this way, we can quantify the modes in which the PSF varies with time by a basis function that characterizes the temporal variations of the reference star as well as the QSO images. To verify the algorithm, we performed a simulation and applied this method to one of the high-z QSO targets from Mechtley et al. We demonstrate that the PCA-based PSF subtraction and further modeling of the galaxy’s light profile using MCMC fitting would sufficiently remove the effects from central dominating point sources, and improve characterization ability for the host galaxies of high-z QSOs to the background noise level which is much better than previous two-component fitting procedures.

关键词： quasars general-galaxies active-galaxies high-redshift-methods data analysis

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A post-processing method for true random number generators based on hyperchaos with applications in audio-based generators

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Frontiers of Computer Science 2020年第6期14卷 85-95页

作者： Je Sen TEH Weijian TENG Azman SAMSUDIN Jiageng CHEN school of Computer sciences Universiti Sains MalaysiaPenang 11800Malaysia school of Engineering and Technology INTI International College PenangPenang 11900Malaysia school of Computer Central China Normal UniversityWuhan 430079China

True random number generators(TRNG)are important counterparts to pseudorandom number generators(PRNG).especially for high security applications such as *** produce unpredictable,non-repeatablerandom ***,most TRNGs require specialized hardware to extract entropy from physical phenomena and tend to be slower than *** generators usually require post-processing algorithms to eliminate biases but in *** *** this paper.a newpost-processing method based on hyperchaos is proposed forsoftware-based TRNGs which not only eliminates statisticalbiases but also provides amplification in order to improve the performance of *** proposed method utilizes the inherent characteristics of chaos such as hypersensitivity to input shanugeri,diffusisn,and csnfusion sapabilities to ushievethese *** bits of a physical entropy source areused to perturb the parameters of a hyperchaotic map,which is then iterated to produce a set of random output *** de-pict the feasibility of the proposed post-processing *** is applied in designing TRNGs based on digital *** are analyzed to identify statistical defects in addition to forward and backward *** indicate that the proposed generators are able to produce secure true random sequences at a high throughput,which in turn reflects on the effectiveness of the proposed post-processing method.

关键词： audio chaos theory chaotic map entropy hyperchaos post-processing random number generator security

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Highly efficient base-free aerobic oxidation of alcohols over gold nanoparticles supported on ZnO-CuO mixed oxides

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Chinese Journal of Catalysis 2019年第12期40卷 1924-1933页

作者： Wei Wang Yan Xie Shaohua Zhang Xing Liu Liyun Zhang Bingsen Zhang Masatake Haruta Jiahui Huang Gold Catalysis Research Center State Key Laboratory of CatalysisDalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina University of Chinese Academy of sciences Beijing 100049China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016LiaoningChina Research Center for Gold Chemistry Department of Applied ChemistryGraduate School of Urban Environmental SciencesTokyo Metropolitan UniversityHachiojiTokyo 192-0379Japan

The design and preparation of suitable supports are of great importance for gold catalysts to attain excellent catalytic performance for alcohol *** this work,we found that ZnO-CuO mixed oxides supported gold catalysts showed much better catalytic activity for base-free aerobic oxidation of benzyl alcohol than Au/ZnO and Au/CuO catalysts,and among them Au/Zn0.7Cu0.3O displayed the best catalytic *** addition,the Au/Zn0.7Cu0.3O catalyst could selectively catalyze the aerobic oxidation of a wide range of alcohols to produce the corresponding carbonyl compounds with high yields under mild conditions without *** characterizations indicated that the outstanding catalytic performance of Au/Zn0.7Cu0.3O was correlated with the small size of Au nanoparticles(NPs),good low-temperature reducibility,high concentration of surface oxygen species,and collaborative interaction between Au NPs and mixed oxide.

关键词： Gold catalysis ZnO-CuO mixed oxides Alcohols Aerobic oxidation Base-free reaction

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Standing Waves of Fractional Schrödinger Equations with Potentials and General Nonlinearities

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Analysis in Theory and Applications 2023年第4期39卷 357-377页

作者： Zaizheng Li Qidi Zhang Zhitao Zhang school of Mathematical sciences Hebei Normal UniversityShijiazhuangHebei 050024China Hebei Center for applied Mathematics ShijiazhuangHebei 050024China Department of Mathematics The University of Hong KongHong KongChina school of Mathematical sciences Jiangsu UniversityZhenjiangJiangsu 212013China HLM Academy of Mathematics and Systems Sciencethe Chinese Academy of SciencesBeijing 100190China school of Mathematical sciences University of Chinese Academy of SciencesBeijing 100049China

We study the existence of standing waves of fractional Schrodinger equations with a potential term and a general nonlinear term:iut-(-Δ)^(s)u-V(x)u+f(u)=0,(t,x)∈R_(+)×R^(N),where s∈(0,1),N>2s is an integer and V(x)≤0 is *** precisely,we investigate the minimizing problem with L2-constraint:E(a)=inf{1/2∫_(R_(N))|(-△)^(s/2)u|^(2)+V(x)|u|^(2)-2F(|u|)|u∈H^(s)(R^(N)),||u||_(L^(2))^(2)(R^(N))=α.Under general assumptions on the nonlinearity term f(u)and the potential term V(x),we prove that there exists a constant a00 such that E(a)can be achieved for all a>a_(0),and there is no global minimizer with respect to E(a)for all 00.

关键词： Fractional Schrodinger equation standing wave normalized solution

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Assessment of Anti-Salmonella Activity of Aqueous and Ethanolic Extract of Senna siamae, Used in Traditional Management of Salmonellosis in Benin

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Pharmacology & Pharmacy 2020年第9期11卷 226-234页

作者： Brice Boris Legba Victorien Dougnon Jerrold Agbankpe Kafayath Fabiyi Christelle Lougbegnon Arnaud Soha Césaire Ayena Esther Deguenon Hornel Koudokpon Lamine Baba-Moussa Research Unit in applied Microbiology and Pharmacology of natural Substances Research Laboratory in Applied Biology Polytechnic School of Abomey-Calavi University of Abomey-Calavi Abomey-Calavi Benin Laboratory of Biology and Molecular Typing in Microbiology Faculty of Sciences and Techniques University of Abomey-Calavi Abomey-Calavi Benin

Recent ethnopharmacological data cited Senna siamea as one of the most widely used medicinal plants in the management of salmonellosis in Benin. However, data related to its activity on non-typhoidal Salmonella spp are limited. This study aimed to assess the antibacterial activity of Senna siamea on multidrug-resistant Salmonella. Ethanolic and aqueous extracts of S. siamea were tested for their antibacterial activity on four multidrug-resistant Salmonella: Salmonella Typhimurium ATCC 14028 and three Salmonella spp. isolated from animals intended for human consumption in Benin. Well diffusion technique combined with the determination by microdilution of Minimum Bactericidal Concentration (MBC) and Minimum Inhibitory Concentration (MIC) were used for antibacterial testing. From antibacterial testing, inhibition diameters of the extracts ranged from 7 to 11 mm, for the susceptible strains. Colistin (reference antibiotic) was active on all

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Characterization and Properties of Bent-Negabent Functions

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Chinese Journal of Electronics 2022年第4期31卷 786-792页

作者： JIANG Niu ZHAO Min YANG Zhiyao ZHUO Zepeng CHEN Guolong school of Mathematical sciences Huaibei Normal University Fujian Provincial Key Laboratory of Network Security and Cryptology Fujian Normal University school of Cyber Science University of Science and Technology of China school of Computer Engineering Bengbu University

A further characterization of the bentnegabent functions is presented. Based on the concept of complete mapping polynomial, we provide a necessary and sufficient condition for a class of quadratic Boolean functions to be bent-negabent. A new characterization of negabent functions can be described by using the parity of Hamming weight. We further generalize the classical convolution theorem and give the nega-Hadamard transform of the composition of a Boolean function and a vectorial Boolean function. The nega-Hadamard transform of a generalized indirect sum is calculated by this composition method.

关键词： Boolean function Bent-negabent function Walsh-Hadamard transform Nega-Hadamard transform

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natural Radioactivity and Excess Lifetime Cancer Risk Associated with Soil in Kargi Area, Marsabit-Kenya

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Journal of Geoscience and Environment Protection 2020年第12期8卷 127-143页

作者： Willis Ougo Aguko Robert Kinyua John Gitonga Githiri Physics Department School of Physical Sciences College of Pure & Applied Sciences Jomo Kenyatta University of Agriculture and Technology Nairobi Kenya

The main aim of investigating activity concentrations together with distribution of radionuclides naturally in soil from Kargi was to evaluate radiological health hazard together with environmental radioactivity. Research shows radionuclides as one source of exposure due to radiation with detrimental effects health wise for populations found in areas considered high background radiation. After collecting 117 soil samples from the area, analysis was done in order to measure their natural radioactivities due to 40K, 232Th and 226Ra radionuclides. Measurements method of gamma spectrometry employing a high purity germanium (HPGe) detector was employed basically to evaluate the radiological hazard of radioactivities. For 40K, 232Th and 226Ra, mean calculated activities were 353.19 ± 110.07, 7.98 ± 3.98 and 7.37 ± 2.60 Bq·kg -1 respectively. Mean values of absorbed and effective dose rates, external and internal hazard indices together with radium equivalent activity were 23.82 ± 6.59 nGy·h -1 and 0.14 ± 0.04 mSv·y -1, 0.12 ± 0.03 and 0.14 ± 0.04 and 45.90 ± 12.65 Bq·kg -1 respectively. Comparing with approved global values, the values were found to be below the given global limits. Evidence of involvement of metasomatic activity of the radioelements or fractionation during weathering is seen as calculations give a higher value Th/U. Excess cancer risk, calculated from the samples showed lower values as compared to global standard values hence minimal chance of getting cancer disease. The area is safe from cancer causing radionuclides.

关键词： Kargi-Marsabit Nuclear Science Gamma-Ray Spectrometry Lifetime Cancer Risk Activity

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A Forecast Error Correction Method in Numerical Weather Prediction by Using Recent Multiple-time Evolution Data

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Advances in Atmospheric sciences 2013年第5期30卷 1249-1259页

作者：薛海乐沈学顺丑纪范 school of Atmospheric sciences Lanzhou University State Key Laboratory of Severe Weather Chinese Academy of Meteorological Sciences Center for Numerical Prediction China Meteorological Administration

The initial value error and the imperfect numerical model are usually considered as error sources of numerical weather prediction （NWP）. By using past multi-time observations and model output, this study proposes a method to estimate imperfect numerical model error. This method can be inversely estimated through expressing the model error as a Lagrange interpolation polynomial, while the coefficients of polyno- mial are determined by past model performance. However, for practical application in the full NWP model, it is necessary to determine the following criteria：（1） the length of past data sufficient for estimation of the model errors, （2） a proper method of estimating the term ＂model integration with the exact solution＂ when solving the inverse problem, and （3） the extent to which this scheme is sensitive to the observational errors. In this study, such issues are resolved using a simple linear model, and an advection diffusion model is applied to discuss the sensitivity of the method to an artificial error source. The results indicate that the forecast errors can be largely reduced using the proposed method if the proper length of past data is chosen. To address the three problems, it is determined that （1） a few data limited by the order of the corrector can be used, （2） trapezoidal approximation can be employed to estimate the ＂term＂ in this study; however, a more accurate method should be explored for an operational NWP model, and （3） the correction is sensitive to observational error.

关键词： numerical weather prediction past data model error inverse problem

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The convergence properties of infeasible inexact proximal alternating linearized minimization

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Science China Mathematics 2023年第10期66卷 2385-2410页

作者： Yukuan Hu Xin Liu State Key Laboratory of Scientific and Engineering Computing Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China school of Mathematical sciences University of Chinese Academy of SciencesBeijing 100049China

The proximal alternating linearized minimization(PALM)method suits well for solving blockstructured optimization problems,which are ubiquitous in real *** the cases where subproblems do not have closed-form solutions,e.g.,due to complex constraints,infeasible subsolvers are indispensable,giving rise to an infeasible inexact PALM(PALM-I).Numerous efforts have been devoted to analyzing the feasible PALM,while little attention has been paid to the *** usage of the PALM-I thus lacks a theoretical *** essential difficulty of analysis consists in the objective value nonmonotonicity induced by the *** study in the present work the convergence properties of the *** particular,we construct a surrogate sequence to surmount the nonmonotonicity issue and devise an implementable inexact *** upon these,we manage to establish the stationarity of any accumulation point,and moreover,show the iterate convergence and the asymptotic convergence rates under the assumption of the Lojasiewicz *** prominent advantages of the PALM-I on CPU time are illustrated via numerical experiments on problems arising from quantum physics and 3-dimensional anisotropic frictional contact.

关键词： proximal alternating linearized minimization infeasibility nonmonotonicity surrogate sequence inexact criterion iterate convergence asymptotic convergence rate

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The Development of a Physical Conservation Fidelity Global Spectral Model-From Dynamic Framework to a Full Model

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Atmospheric and Oceanic Science Letters 2008年第1期1卷 33-35页

作者： ZHONG Qi ZHONG Qing Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China graduate University of Chinese Academy of sciences Beijing 100049 China

The fidelity scheme of physical conservation laws has been applied in the dynamic framework of a global spectral model. In this study, a set of diabatic physical processes are also involved. Based on six 30-day numerical integrations of real-time data, we show that the full model is able to reproduce the primary features of global energy cycle and hydrological distribution. Additionally, the root-mean-square error is dramatically decreased when diabatic processes are considered. Another advantage is that the false structure of ＂double Intertropical Convergence Zone （ITCZ）＂ is not seen in the result, although the orecioitation rate becomes lower.

关键词： fidelity of physical conservation laws spec-tral model energy cycle systematic error

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