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Tracking the maneuvering spacecraft propelled by swing propulsion of constant magnitude

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Journal of Systems Engineering and Electronics 2020年第2期31卷 370-382页

作者： ZHAI Guang WANG Yanxin zhao qi School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Systems Engineering Research Institute Beijing 100094China

This paper proposes partially norm-preserving filtering for a class of spacecraft in the presence of time-varying, but constant-magnitude maneuver. The augmented state Kalman filter(ASKF) is commonly used to track the maneuvering spacecraft with unknown constant propulsion;however, if the maneuver varies via time, the estimation performance will be degraded. To promote the tracking performance of the ASKF in case of time-invariant,constant-magnitude disturbance, the partially norm-preserving ASKF is developed by applying the norm constraint on the unknown maneuver. The proposed estimator, which is decomposed into two partial estimators and iteratively propagated in turns,projects the unconstrained maneuver estimation onto the Euclidian surface spanned by the norm constraint. The illustrative numerical example is provided to show the efficiency of the proposed method.

关键词： maneuvering spacecraft tracking augmented state norm-preserving Kalman filter

Integration of GPS and low cost INS for pedestrian navigation aided by building layout

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Chinese Journal of Aeronautics 2013年第5期26卷 1283-1289页

作者： Feng Wenquan zhao Hongbo zhao qi Li Jingwen School of Electronics and Information Engineering Beihang University

In outdoor environments, GPS is often used for pedestrian navigation by utilizing its signals for position computation, but in indoor or semi-obstructed environments, GPS signals are often unavailable. Therefore, pedestrian navigation for these environments should be realized by the integration of GPS and inertial navigation system （INS）. However, the lowcost INS could induce errors that may result in a large position drift. The problem can be minimized by mounting the sensors on the pedestrian＇s foot, using zero velocity update （ZUPT） method with the standard navigation algorithm to restrict the error growth. However, heading drift still remains despite using ZUPT measurements since the heading error is unobservable. Also, tbot mounted INS suffers from the initialization ambiguity of position and heading from GPS. In this paper, a novel algorithm is developed to mitigate the heading drift problem when using ZUPT. The method uses building lay- out to aid the heading measurement in Kalman filter, and it could also be combined for the initial- ization. The algorithm has been investigated with real field trials using the low cost Microstrain 3DM-GX3-25 inertial sensor, a Leica GS10 GPS receiver and a uBlox EVK-6T GPS receiver. It could be concluded that the proposed method offers a significant improvement in position accuracy for the long period, allowing pedestrian navigation for nearly40 min with mean position error less than 2.8 m. This method also has a considerable effect on the accuracy of the initialization.

关键词： Heading drift Initialization Integrated navigation Pedestrian navigation Satellite navigation Zero velocity update

Topography of InP Surface Bombarded by O_(2)^(+) Ion Beam

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Chinese Physics Letters 1997年第10期14卷 760-763页

作者： SUN zhao-qi Department of Physics Anhui UniversityHefei 230039

The topography of InP surface bombarded by O_(2)^(+) ion beam was *** topographies were observed for bombarded samples,and the data show that the ripple formation starts from a sputtering depth of about 0.4μ*** wavelength and the disorder of the ripples both increase as the sputtering depth *** wavelength of the ripples appears to be sputtering depth dependent rather than sputtering rate *** is confirmed that the ion-beam-induced surface rippling can be effectively suppressed by sample rotation during bombardment.

关键词： InP beam sputtering

The role of copper in enhancing the performance of heteronuclear diatomic catalysts for the electrochemical CO_(2)conversion to C_(1) chemicals

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Journal of Energy Chemistry 2023年第10期85卷 490-500,I0013页

作者： qi zhao Rachel Crespo-Otero Devis Di Tommaso Department of Chemistry School of Physical and Chemical SciencesQueen Mary University of LondonLondon E14NSUK Department of Chemistry University College LondonLondon WC1H 0AJUK

Diatomic catalysts(DACs)with two adjacent metal atoms supported on graphene can offer diverse functionalities,overcoming the inherent limitations of single atom catalysts(SACs).In this study,density functional theory calculations were conducted to investigate the reactivity of the carbon dioxide(CO_(2))reduction reaction(CO_(2)RR)on metal sites of both DACs and SACs,as well as their synergistic effects on activity and *** of the Gibbs free energies of CO_(2)RR and associated values of the limiting potentials to generate C_(1) products showed that Cu acts as a promoter rather than an active catalytic centre in the catalytic CO_(2)conversion on heteronuclear DACs(CuN_(4)-MN_(4)),improving the catalytic activity on the other metal compared to the related SAC MN_(4).Cu enhances the initial reduction of CO_(2)by promoting orbital hybridization between the key intermediate*COOH 2p-orbitals and the metals 3d-orbitals around the Fermi *** degree of hybridization in the DACs CuN_(4)-MN_(4) decreases from Fe to Co,Ni,and *** work demonstrates how Cu regulates the CO_(2)RR performance of heteronuclear DACs,offering an effective approach to designing practical,stable,and high-performing diatomic catalysts for CO_(2)electroreduction.

关键词： Electrocatalytic CO_(2)reduction Single atom catalysts Diatomic catalysts Graphene Density functional theory calculations

Better nutrition, healthier mind? Experimental evidence from primary schools in rural northwestern China

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Journal of Integrative Agriculture 2019年第8期18卷 1768-1779页

作者： LIU Xiao-yue zhao qi-ran CHEN qi-hui Center for Food and Health Economic Research College of Economics and Management China Agricultural University

Malnutrition and mental health problems are both prevalent among rural students in China. To provide a better understanding of the functional linkage between these two problems, this study estimates the causal effect of improved nutrition on rural students’ mental health status, exploiting a randomized controlled trial involving 6 044 fourth and fifth graders in rural northwestern China. Estimation results show that a nutrition subsidy provided by the project significantly improved students’ mental health status(measured by their anxiety scale). However, an add-on incentive provided to school principals, which was tied to anemia reduction, almost entirely offset the beneficial impact of the nutrition subsidy. These findings suggest that to improve students’ mental health in rural China, not only direct subsidies, such as low-priced school meals, but also correct incentives, especially those tied closely to students’ mental health outcomes, should be provided.

关键词： malnutrition mental health randomized controlled trial rural China

Shakespeare　as　an　Ironist　(Ⅰ)

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外语教学 1995年第4期16卷 56-61页

作者： $$$$zhao qi

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ＳｈａｋｅｓｐｅａｒｅａｓａｎＩｒｏｎｉｓｔ（Ⅰ）￥ＺｈａｏＱｉＯｆａｌｌｔｈｅｆｉｇｕｒｅｓｏｆｓｐｅｅｃｈｕｓｅｄｂｙＳｈａｋｅｓｐｅａｒｅｉｎｈｉｓｇｒｅａｔｗｏｒｋｓ，ｉｒｏｎｙｐｌａｙｓａｖｅｒｙｉｍｐｏｒｔａｎｔｒｏｌｅ．Ｈｅｐｒｏｖｅｄ...

关键词： Shakespeare

1-set-contractive perturbations of accretive operators in Menger PN-spaces

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Applied Mathematics(A Journal of Chinese Universities) 2012年第3期27卷 363-370页

作者： WU zhao-qi ZHU Chuan-xi Department of Mathematics Nanchang UniversityNanchang 330031China

Based on the topological degree for 1-set-contractive fields established in [11], we discuss the 1-set-contractive perturbation and the existence of zero points for nonlinear equations with accretive mappings in Menge... 详细信息

关键词： topological degree 1-set-contractive perturbation accretive mapping.

Topological degree for 1-set-contractive fields in M-PN spaces and its applications

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Applied Mathematics(A Journal of Chinese Universities) 2010年第4期25卷 463-474页

作者： WU zhao-qi ZHU Chuan-xi Department of Mathematics Zhejiang University Hangzhou 310027 China Department of Mathematics Nanchang University Nanchang 330031 China

In this paper, we define the topological degree for 1-set-contractive fields in PN spaces. Based on this, we obtain some new fixed point theorems for 1-set-contractive operators. As an application, we study the existe... 详细信息

关键词： PN-space 1-set-contractive operator topological degree fixed point theorem.

Distributed Real-time State Estimation for Combined Heat and Power Systems

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Journal of Modern Power Systems and Clean Energy 2021年第2期9卷 316-327页

作者： Tingting Zhang Wen Zhang qi zhao Yaxin Du Jian Chen Junbo zhao the Key Laboratory of Power System Intelligent Dispatch and Control Ministry of EducationShandong UniversityJinan 250061China the Department of Electrical and Computer Engineering Mississippi State UniversityStarkvilleMS 39762USA

This paper proposes a distributed real-time state estimation(RTSE)method for the combined heat and power systems(CHPSs).First,a difference-based model for the heat system is established considering the dynamics of heat *** heat system model is further used along with the power system steady-state model for holistic CHPS state estimation.A cubature Kalman filter(CKF)-based RTSE is developed to deal with the system nonlinearity while integrating both the historical and present measurement ***,a multi-timescale asynchronous distributed computation scheme is designed to enhance the scalability of the proposed method for largescale *** distributed implementation requires only a small amount of information exchange and thus protects the privacy of different energy *** carried out on two CHPSs show that the proposed method can significantly improve the estimation efficiency of CHPS without loss of accuracy compared with other existing models and methods.

关键词： Combined heat and power system(CHPS) cubature Kalman filter(CKF) heat dynamics multi-time-scale asynchronous distributed scheme real-time state estimation(RTSE)