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A Photometric Study of the W UMa-Type Contact Binary RZ Com

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Chinese Journal of Astronomy and Astrophysics 2008年第4期8卷 465-471页

作者： jia-jia he Sheng-Bang Qian National Astronomical Observatories / Yunnan Observatory Chinese Academy of Sciences Kunming 650011 China United Laboratory of Optical Astronomy Chinese Academy of Sciences （ULOAC） Beijing 100012 China Graduate School of Chinese Academy of Sciences Beijing 100049 China

We present results of CCD photometric observations of the short-period W UMatype contact binary system, RZ Com. The light curve of the binary has changed from Wsubtype to A-subtype from 1998 to 2003, then back to W-subtype in 2004. An analysis was carried out using the 2003 version of the Wilson-Devinney code. It is confirmed that RZ Com is a low-degree, overcontact f = 20.1% （±7.4%） binary system with a high inclination of i = 81.°40 （＋0.°40）, and a mass ratio q = 2.351 （＋0.031）. Combining four newly determined times of light minimum with others in the literature, the variations in orbital period is examined. A small-amplitude oscillation （A=0.0065d）, with a period of 41.5 year, is discovered superimposed on a long-term increase at rate dP/dt = ＋3.97 × 10^-8d yr^-1. The period oscillation can be explained either by the light-time effect due to the presence of an unseen third body, or by cycles of magnetic activity on the components. Combining our photometric solution with the spectroscopic elements obtained by Mclean ＆ Hilditch, the absolute dimensions ofRZ Com are： M1 = 1.14 （±0.19）M⊙, M2 = 0.50 （±0.09）M⊙, R1 = 1.12 （±0.01）R⊙, R2 = 0.78 （＋0.01）R⊙ and A = 2.41 （±0.02）R⊙.

关键词： stars binaries close - stars binaries eclipsing - stars individual RZ Com

A Study on the Pros and Cons of China＇ s Financial Openness

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学术界 2014年第3期 274-280页

作者： he jia School of Economics and Management Neijiang Normal University Neijiang Sichuan 641112

In 2008,the U. S. subprime mortgage crisis triggered global financial crisis quickly and spread all over the w orld,w hich caused serious losses to many countries. T herefore,w hether china should insist on financial market opening have become a hot topic to debate. T his article discussed the advantages and disadvantages on C hinese financial market opening. It firstly review ed opening history of C hina's financial market,and then analyzed its current situation from three aspects including banking,securities industry and insurance ***,the paper introduced the benefits and problems of financial market opening to the outside w orld,and provided suggestions for the opening process.

关键词：金融危机中国利弊分析金融市场市场开放 ing 保险业证券业

Bayesian dual neural networks for recommendation

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Frontiers of Computer Science 2019年第6期13卷 1255-1265页

作者： jia he Fuzhen ZHUANG Yanchi LIU Qing he Fen LIN Key Lab of Intelligent Information Processing of Chinese Academy of Sciences Institute of Computing TechnologyChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Rutgers University Newark 07102USA Search Product Center WeChat Search Application DepartmentTencentBeijing 100080China

Most traditional collaborative filtering(CF)methods only use the user-item rating matrix to make recommendations,which usually suffer from cold-start and sparsity *** address these problems,on the one hand,some CF methods are proposed to incorporate auxiliary information such as user/item profiles;on the other hand,deep neural networks,which have powerful ability in learning effective representations,have achieved great success in recommender ***,these neural network based recommendation methods rarely consider the uncertainty of weights in the network and only obtain point estimates of the ***,they maybe lack of calibrated probabilistic predictions and make overly confident *** this end,we propose a new Bayesian dual neural network framework,named BDNet,to incorporate auxiliary information for ***,we design two neural networks,one is to learn a common low dimensional space for users and items from the rating matrix,and another one is to project the attributes of users and items into another shared latent *** that,the outputs of these two neural networks are combined to produce the final ***,we introduce the uncertainty to all weights which are represented by probability distributions in our neural networks to make calibrated probabilistic *** experiments on real-world data sets are conducted to demonstrate the superiority of our model over various kinds of competitors.

关键词： collaborative filtering Bayesian neural network hybrid recommendation algorithm

New multi-color photometric investigations of solar-like contact binary V680 Per

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Research in Astronomy and Astrophysics 2020年第4期20卷 49-56页

作者： Jing-Jing Wang jia-jia he Song-Qing Zhao China University of Petroleum–Beijing at Karamay Karamay 834000China Yunnan Observatories Chinese Academy of SciencesKunming 650216China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China

High-precision CCD photometric observations of the contact binary V680 Per were obtained *** symmetric multi-color light curves were analyzed by using the Wilson–Devinney(2013)*** photometric solutions suggest that V680 Per is an A-type W UMa contact binary with the mass ratio of q=0.693 and a fill-out factor of f=18.84%with a small temperature difference of 101 *** on all minimum times,the O-C curve was analyzed for the first time in this study.A cyclic oscillation(A3=0.00093 d,T3=4.92 yr)superimposed on a secular decrease(d P/dt=-8.16×10-8 d yr-1)was *** continuous decrease in period is possibly a result of mass transfer from the more massive component to the less massive one,or angular momentum loss due to a magnetic stellar *** of this secular decrease,it is predicted that the degree of contact will become higher,and V680 Per will evolve into a deeper overcontact binary.

关键词： binaries:eclipsing stars:solar-type stars:individual(V680 Per)

Ultra-low lattice thermal conductivity and promising thermoelectric figure of merit in borophene via chlorination

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Nano Research 2022年第4期15卷 3804-3811页

作者： jia he Yanxiao Hu Dengfeng Li Jie Chen Center for Phononics and Thermal Energy Science China–EU Joint Lab for NanophononicsSchool of Physics Science and EngineeringTongji UniversityShanghai 200092China School of Science Chongqing University of Posts and TelecommunicationsChongqing 400065China

Monolayer boron-based materials are of current interests due to its ***,motivated by the recent experimental synthesis of semiconducting hydrogenatedαʹ-borophene and the regulation of the physical properties in layered materials by surface functionalization,we study the thermal and electronic properties ofαʹ-borophene with three different types of gas functional groups(H,F,and Cl)based on first-principles and Boltzmann transport *** is found thatαʹ-borophene can be well stabilized by fluorination and chlorination and maintain the semiconductor *** interestingly,when hydrogen is replaced with fluorine or chlorine,the lattice thermal conductivity changes from 24.3 to 5.2 or 0.73 W/(m·K)along armchair direction at 300 K,exhibiting a huge reduction by two orders of *** main reason is the decrease of both phonon group velocities and acoustic phonon relaxation time resulting from the strong phonon mode softening due to the weaken B-B bond strength and heavier atomic mass of fluorine and ***,the chlorinatedαʹ-borophene exhibits a high thermoelectric figure of merit~2 at 300 K along armchair *** study illustrates the importance of the modulation of transport properties by gas functional groups,which may promote the thermoelectric application of boron-based materials.

关键词： borophene thermal transport thermoelectric figure of merit density functional theory gas atom functionalization

Identification of temperature anomaly RR Lyrae stars in LAMOST survey,misclassification and binarities

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Research in Astronomy and Astrophysics 2020年第6期20卷 239-252页

作者： Lin-jia Li Sheng-Bang Qian jia Zhang jia-jia he Li-Ying Zhu Yunnan Observatories Chinese Academy of SciencesKunming 650216China Key laboratory of 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 100049China

RR Lyrae stars,a well-known type of pulsating variable stars,have been known about for more than a century.A large amount of photometric data on RR Lyrae stars has been accumulated by space-and ground-based sky surveys,but the spectral data are relatively ***,the LAMOST sky survey project provides an opportunity to view them from the point of view of *** collect the atmospheric parameters of 1685 RR Lyrae stars provided by the LAMOST catalog,and carry out research by using the reliable *** find that there is a clear correlation between their Teff and pulsation periods,which is consistent with the pulsation and evolution theories of RR Lyrae *** addition,we focus on those RR Lyrae stars with abnormal *** analyzing the data from several photometric surveys,we find that some of these temperature anomalies are misclassified variable stars(e.g.,eclipsing binaries,pulsating stars on main sequence),and some are RR Lyrae binary *** the latter,the temperatures of potential companions should be lower and their luminosities should not be neglected(e.g.,red giant stars).We obtain that the ratio of temperature anomaly stars to all the sample stars is 4%,which means that the impact on the further analysis(e.g.,kinematics analysis)is *** also present the catalogs of spectral anomaly RR Lyrae stars.

关键词： techniques spectroscopic-techniques photometric-stars fundamental parameters-stars variables RR Lyrae

Wavelet network based predistortion method for wideband RF power amplifiers exhibiting memory effects

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第4期8卷 625-630页

作者： JIN Zhe SONG Zhi-huan he jia-ming School of Information Science and Engineering Zhejiang University Hangzhou 310027 China Institute of Communication Technologies Ningbo University Ningbo 315211 China

RF power amplifiers (PAs) are usually considered as memoryless devices in most existing predistortion techniques. Nevertheless, in wideband communication systems, PA memory effects can no longer be ignored and memoryless predistortion cannot linearize PAs effectively. After analyzing PA memory effects, a novel predistortion method based on wavelet networks (WNs) is proposed to linearize wideband RF power amplifiers. A complex wavelet network with tapped delay lines is applied to construct the predistorter and then a complex backpropagation algorithm is developed to train the predistorter parameters. The simulation results show that compared with the previously published feed-forward neural network predistortion method, the proposed method provides faster convergence rate and better performance in reducing out-of-band spectral regrowth.

关键词： Power amplifiers. Predistortion. Memory effects. Wavelet networks

Persymmetric adaptive detection of range-spread targets in subspace interference plus Gaussian clutter

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Science China(Information Sciences) 2023年第5期66卷 271-282页

作者： Tao jiaN jia he Yu LIU You he Congan XU Zikeng XIE Research Institute of Information Fusion Naval Aviation University

In this paper, we consider the adaptive detection problem of range-spread targets embedded in subspace interference plus structured Gaussian clutter. The target signal and interference are assumed to lie in two linearly independent subspaces with unknown coordinates. The clutter component is modeled as a complex Gaussian vector with an unknown persymmetric covariance matrix. We leverage the persymmetric structure to design a two-step detector according to the Rao test criterion. The theoretical results show that the proposed detector possesses the constant false alarm rate property with respect to the clutter covariance matrix. Furthermore, the numerical results show that the proposed detector exhibits better detection performance than the existing unstructured subspace detectors, particularly under a limited training data size. In addition, the proposed detector outperforms the existing persymmetric subspace detectors.

关键词： adaptive detection persymmetry structured interference constant false alarm rate Rao test

Revision of the photometric parameters of BS Cassiopeiae

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Research in Astronomy and Astrophysics 2010年第6期10卷 569-576页

作者： jia-jia he Sheng-Bang Qian Miloslav Zejda Zdenek Mikulasek National Astronomical Observatories / Yunnan Observatory Chinese Academy of Sciences Kunming 650011 China Graduate University of the Chinese Academy of Sciences Beijing 100049 China Key Laboratory for the Structure and Evolution of Celestial Objects National Astronomical Observatories/Yunnan Observatory Chinese Academy of Sciences Kunming 650011 China Institute of Theoretical Physics and Astrophysics Masaryk University Kotlarska 2 611 37 Brno Czech Republic Observatory and Planetarium of J. Palisa VSB- Technical University Ostrava Czech Republic

Seven charge-coupled device （CCD） photometric times of light minimum of the overcontact binary BS Cas which were obtained from 2007 August to November and one CCD light curve in the R band which was observed on 2007 September 24 and October 15, are presented. It is found that the light curve ofBS Cas has characteristics like a typical EW-type light variation. The light curve obtained by us is symmetric and shows total eclipses, which is very useful for determining photometric parameters with high precision. Photometric solutions were derived by using the 2003 version of the Wilson-Devinney code. It shows that BS Cas is a W-subtype overcontact binary （f = 27.5% ± 0.4%） with a mass ratio of q = 2.7188± 0.0040. The temperature difference between the two components is 190 K. Analysis of the 042 curve suggests that the period of AE Phe shows a long-term continuous decrease at a rate of dP/dt = - 2.45 × 10^-7 d yr^- 1 The long-time period decrease can be explained by mass transfer from the primary to the secondary.

关键词： stars binaries close -- stars binaries eclipsing -- stars individual BS Cas