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An Improved Method of Ambiguity Resolution in GNSS Positioning

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Chinese Journal of Electronics 2019年第1期28卷 215-222页

作者： gu Xiaoying ZhU Bocheng School of Electronics Engineering and Computer Science Peking University

high precision navigation with positioning accuracy of decimeter or even centimeter is becoming more and more important in many fields. Accurate carrier phase observations are the prerequisites for this requirement. Because they have much lower measurement noises than the code observations which are primarily used nowadays. however, the existence of integer ambiguity when counting cycles of carrier phases prohibits the straightforward application of the measurements. Once the integer ambiguity has been resolved, the application of carrier phase measurement is almost equivalent to pseudorange however with much higher precision. Therefore ambiguity resolution is key for fast and high precision positioning. The success rate of ambiguity resolution is affected by the ionospheric delay and observation noise. In previous methods, ionospheric errors are simply ignored. To resolve ambiguity reliably and quickly, we propose a modified method for precise point *** analyze the characteristics of the dual-frequency combinations of original observations and the ones with longer wavelengths and lower noises are preferable. The wide-lane and sub-wide-lane combinations with higher success rates are chosen for ambiguity resolution. Extra pseudoranges are included to eliminate the ionospheric delay which hampers ambiguity resolution seriously. After the combined ambiguities have been resolved, the original ambiguities of each frequency can be calculated from the linearly independent equations. Based on real Global positioning system(GPS) navigation data, performances of the modified method are tested and compared with that of the traditional method. The results show that the modified method is less affected by ionospheric delay and can obtain more accurate ambiguity resolution.

关键词： Global navigation satellite system Integer ambiguity resolution Precise point positioning high precision positioning

Semi-clathrate hydrate based carbon dioxide capture and separation techniques

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Frontiers of Environmental Science & Engineering 2023年第12期17卷 1-29页

作者： Lijuan gu hailong Lu Beijing International Center for Gas hydrate School of Earth and Space SciencesPeking UniversityBeijing 100871China National Engineering Research Center for Gas hydrate Exploration and Development Guangzhou 511466China

CO_(2)is considered as the main contributor to global warming,and hydrate enclathration is an efficient way for carbon capture and separation(CCS).Semi-clathrate hydrate(SCh)is a type of clathrate hydrate capable of encaging CO_(2)molecules under mild temperature and pressure *** has numerous unique advantages,including high thermal stability,selective absorption of gas molecules with proper size and recyclable,making it a promising candidate for *** SCh based CCS technology is in the developing stage and great efforts have to be conducted to improve the performance that is determined by their thermodynamical and structural *** review summarizes and compares the thermodynamic and structural properties of SCh and quaternary salt hydrates with gas mixtures to be captured and *** on the description of the physical properties of SCh and hydrate of quaternary salts with gas mixture,the CO_(2)capture and separation from fuel gas,flue gas and biogas with SCh are *** review focuses on the use of tetra-nbutyl ammonium halide and tetra-n-butyl phosphonium halide,which are the current application *** review aims to provide guidance for the future applications of SCh.

关键词： Semi-clathrate hydrate Tetra-n-butyl ammonium halide Tetra-n-butyl phosphonium halide Structure Thermodynamical properties CO_(2) capture and separation

A high-Order Fully Actuated System Approach for a Class of Nonlinear Systems

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Journal of Systems Science & Complexity 2022年第2期35卷 714-730页

作者： gu Dake WANG Shuo School of Automation Engineering Northeast Electric Power UniversityJilin 132012China

This paper utilizes the high-order fully actuated(hOFA)system approach to synthesize a class of nonlinear ***,the original nonlinear system can be rewritten in a quasi-linear form,which is more general than other nonlinear systems,such as strict-feedback *** on a rank condition,the quasi-linear system can be transformed into a canonical ***,a simple transformation is adopted to convert the above canonical form into the hOFA *** an hOFA model is derived,the authors design a controller to make the closed-loop system a constant linear system with the desired ***,a numerical example illustrates the fitness and effectiveness of the proposed approach.

关键词： Canonical form closed-loop eigenstructure full-actuation high-order systems quasilinear systems

A Perspective for Developing Polymer-Based Electromagnetic Interference Shielding Composites

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Nano-Micro Letters 2022年第6期14卷 39-47页

作者： Yali Zhang Junwei gu Shaanxi Key Laboratory of Macromolecular Science and Technology School of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi’an 710072ShaanxiPeople’s Republic of China

The rapid development of aerospace weapons and equipment,wireless base stations and 5G communication technologies has put forward newer and higher requirements for the comprehensive performances of polymer-based electromagnetic interference(EMI)shielding ***,most of currently prepared polymer-based EMI shielding composites are still difficult to combine high performance and *** response to this,based on the research works of relevant researchers as well as our research group,three possible directions to break through the above bottlenecks are proposed,including construction of efficient conductive networks,optimization of multi-interfaces for lightweight and multifunction compatibility *** future development trends in three directions are prospected,and it is hoped to provide certain theoretical basis and technical guidance for the preparation,research and development of polymer-based EMI shielding composites.

关键词： Polymer composites Electromagnetic interference shielding Conductive network Lightweight

A classical algorithm to mimic quantum decisions

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National Science Review 2019年第4期6卷 608-609页

作者： Mile gu School of Physical and Mathematical Sciences Nanyang Technological University

In his famous 1982 lecture, Nobel laureate Richard Feynman seeded the idea of quantum computation. he reasoned that the amount of classical information required to describe a quantum system scaled exponentially with its size, and thus could not be efficiently simulated by a classical computer. Indeed, a fairly modest system of 100 quantum bits would already require more information to describe than all the present data storage

关键词： A classical algorithm to mimic quantum decisions

Remote Interference Source Localization: A Multi-UAV-Based Cooperative Framework

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Chinese Journal of Electronics 2022年第3期31卷 442-455页

作者： WU guangyu gu Jiangchun Department of Computer Science and Technology University of Science and Technology of China School of Communication Engineering Army Engineering University of PLA

Interference source localization with high accuracy and time efficiency is of crucial importance for protecting spectrum resources. Due to the flexibility of unmanned aerial vehicles(UAVs), exploiting UAVs to locate the interference source has attracted intensive research interests. The off-the-shelf UAV-based interference source localization schemes locate the interference sources by employing the UAV to keep searching until it arrives at the target. This obviously degrades time efficiency of localization. To balance the accuracy and the efficiency of searching and localization, this paper proposes a multi-UAV-based cooperative framework alone with its detailed scheme, where search and remote localization are iteratively performed with a swarm of UAVs. For searching, a low-complexity Q-learning algorithm is proposed to decide the direction of flight in every time interval for each UAV. In the following remote localization phase, a fast Fourier transformation based location prediction algorithm is proposed to estimate the location of the interference source by fusing the searching result of different UAVs in different time intervals. Numerical results reveal that in the proposed scheme outperforms the stateof-the-art schemes, in terms of the accuracy, the robustness and time efficiency of localization.

关键词： unmanned aerial vehicles low-complexity Q-learning algorithm path planning fast Fourier transforms remote interference source localization multi-robot systems UAV swarm mobile robots remote localization location prediction algorithm aerospace robotics autonomous aerial vehicles learning (artificial intelligence) fast Fourier transformation cooperative communication spectrum resources radiofrequency interference mobile radio flight direction multiUAV-based cooperative framework

Parameter feature extraction for hyperspectral detection of the shallow underwater target

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Science China(Technological Sciences) 2021年第5期64卷 1092-1100页

作者： XIA Zhi gu YanFeng Acoustic Science and Technology Laboratory Harbin Engineering UniversityHarbin 150001China College of Underwater Acoustic Engineering Harbin Engineering UniversityHarbin 150001China School of Electronics and Information Engineering Harbin Institute of TechnologyHarbin 150001China

For the detection of shallow underwater targets by the hyperspectrum, the information of the target is carried in the water-leaving radiation. however, the differences between the water-leaving radiation of the underwater target and the ocean background radiation are not significant, and the spectrum of the water-leaving radiation is sensitive to the changes of the marine environment. Therefore, taking the spectrum as the feature is not stable for hyperspectral detection of the underwater target. In this paper, we propose a parameter feature extraction method for hyperspectral detection of the shallow underwater target. The presence of an underwater target would change the optical properties of seawater in a local place. Based on that, a quasianalytical model of the water-leaving radiation is adopted to inverse the properties of the marine environment from the radiated spectrum. Then the inversed water depth and bottom reference reflectance are taken as the features. Simulation results show that the samples which belong to the water-leaving radiation of underwater target have higher inversed depth and reference reflectance than that belong to the ocean background radiation. Furthermore, these two kinds of samples can be separated significantly and stably in a 2-dimension feature space.

关键词： hyperspectral imaging underwater technology feature extraction

Dancing of electromagnetic spectra driven by metasurfaces

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National Science Review 2019年第3期6卷 379-380页

作者： Min gu Laboratory of Artificial-Intelligence Nanophotonics School of Science RMIT University

In 2011, Capasso proposed the concept of manipulating electromagnetic (EM) waves with phase modulation by an ultrathin flat metasurface composed of nanoantenna arrays[1]. Later, researchers developed different kinds of new metasurfaces, such as hyperbolic metasurfaces, tunable metasurfaces and non-linear metasurfaces[2]. The development of metasurfaces has greatly enhanced the capability to manipulate EM waves with multiple functionalities

关键词： Dancing of electromagnetic spectra driven by metasurfaces domain DCM

Latest research progress for LBE coolant reactor of China initiative accelerator driven system project

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Frontiers in Energy 2021年第4期15卷 810-831页

作者： Long gu Xingkang SU Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China School of Nuclear Science and Technology Lanzhou UniversityLanzhou 730000China

China’s accelerator driven subcritical system(ADS)development has made significant progress during the past *** the successful construction and operation of the international prototype of ADS superconducting proton linac,the lead-based critical/subcritical zero-power facility VENUS-II and the comprehensive thermal-hydraulic and material test facilities for LBE(lead bismuth eutectic)coolant,China is playing a pivotal role in advanced steady-state operations toward the next step,the ADS *** China initiative Accelerator Driven System(CiADS)is the next facility for China’s ADS program,aimed to bridge the gaps between the ADS experiment and the LBE cooled subcritical *** total power of the CiADS will reach 10 *** CiADS engineering design was approved by Chinese government in *** then,the CiADS project has been fully transferred to the construction application *** subcritical reactor is an important part of the whole CiADS ***,a pool-type LBE cooled fast reactor is chosen as the subcritical reactor of the *** and thermal experiments and software development for LBE coolant were conducted simultaneously to support the design and construction of the CiADS LBEcooled subcritical ***,it is necessary to introduce the efforts made in China in the LBE-cooled fast reactor to provide certain supporting data and reference solutions for further design and development for ***,the roadmap of China’s ADS,the development process of the CiADS,the important design of the current CiADS subcritical reactor,and the efforts to build the LBE-cooled fast reactor are presented.

关键词： LBE(lead bismuth eutectic)coolant reactor China initiative Accelerator Driven System(CiADS)project research progress