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On-orbit real-time magnetometer bias determination for micro-satellites without attitude information

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Chinese Journal of Aeronautics 2015年第5期28卷 1503-1509页

作者： Zhang zhen Xiong Jianping jin jin Department of Precision Instrument Tsinghua University Space Center Tsinghua University

Due to the disadvantages such as complex calculation, low accuracy of estimation, and being non real time in present methods, a new real-time algorithm is developed for on-orbit mag- netometer bias determination of micro-satellites without attitude knowledge in this paper. This method uses the differential value approach. It avoids the impact of quartic nature and uses the iterative method to satisfy real-time applications. Simulation results indicate that the new real-time algorithm is more accurate compared with other methods, which are also tested by an experiment system using real noise data. With the new real-time algorithm, a magnetometer calibration can be taken on-orbit and will reduce the demand for computing power effectively.

关键词： Magnetometer bias:On-orbit determinationMicro-satellite Attitude-independent Real-time

Stereoselective Synthesis of (±) Neocnidilide

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Chinese Chemical Letters 2003年第2期14卷 127-129页

作者： Xiao zhen jiao Ping XIE 等 InstituteofMateriaMedica ChineseAcademyofMedicalSciences&PckingUnivonMedicalCollegeBeijing100050 InstituteofMateriaMedica ChineseAcademyofMedicalSciences&PckingUnivonMedical

The racemic neocnidilide has been synthesized by stereoselective reaction of hemiacetal 5 with n-BuMgBr.

关键词： Neocnidilide stereoselective synthesis.

Factors influencing water quality indices in a typical urban river originated with reclaimed water

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Frontiers of Environmental Science & Engineering 2017年第4期11卷 73-82页

作者： jiao Zhang zhen Wei Haifeng Jia Xia Huang State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing 100084 China

The water quality in a typical urban river segment originated with reclaimed water in Beijing was monitored for two years to investigate the evolution of water quality along the rivcr, and statistical analysis was applied to determine factors influencing water quality of such river recharged by reclaimed water. It was found that no significant change in pollutant concentrations （including COD, NH4＋-N, TN and TP） was observed during this time, and their average values were close to those of the original reclaimed water. However, turbidity and algal contents fluctuated temporally in the direction of river flow. Statistical analysis showed that turbidity was strongly positively correlated with algal contents for flow rate 〈 0.1 m.s-1. whereas it was strongly positively correlated with both algalcontents and TOC for flow rate 〉 0. 1m. s-1. It was observed that diatom was the absolute predominant phyla with Melosira as the major species. In terms of algal bloom control, the specific growth rate of algae was strongly correlated to temperature, and was influenced by flow rate as well. Compared with two other rivers originated with reclaimed water and one originated with natural water, the Shannon Wiener index in the objective river was the lowest, with values between 0.7 and 1.6, indicating a high risk for algal bloom. Statistics showed that Shannon Wiener index was strongly negatively correlated to nutrient salts and cations.

关键词： Reclaimed water Urban river Turbidity Algae Flow rate

Changing law of launching pitching angular velocity of rotating missile

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Chinese Journal of Aeronautics 2014年第5期27卷 1171-1179页

作者： Liu Guang Xu Bin jiao Xiaojuan zhen Tiesheng Department of Mechanics and Engineering Science Fudan University Shanghai Electro-Mechanical Engineering Institute

In order to provide accurate launching pitching angular velocity（LPAV） for the exterior trajectory optimization design, multi-flexible body dynamics（MFBD） technology is presented to study the changing law of LPAV of the rotating missile based on spiral guideway. An MFBD virtual prototype model of the rotating missile launching system is built using multi-body dynamics modeling technology based on the built flexible body models of key components and the special force *** built model is verified with the frequency spectrum analysis. With the flexible body contact theory and nonlinear theory of MFBD technology, the research is conducted on the influence of a series of factors on LPAV, such as launching angle change, clearance between launching canister and missile,thrust change, thrust eccentricity and mass eccentricity, etc. Through this research, some useful values of the key design parameters which are difficult to be measured in physical tests are obtained. Finally,a simplified mathematical model of the changing law of LPAV is presented through fitting virtual test results using the linear regression method and verified by physical flight tests. The research results have important significance for the exterior trajectory optimization design.

关键词： LPAV MFBD Modeling Rotating missile Simulation Virtual prototyping

Premature thermal decomposition behavior of 3,4-dinitrofurazanfuroxan with certain types of nitrogen-rich compounds

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Defence Technology（防务技术） 2023年第8期26卷 102-110页

作者： jiao Huang Ru-fang Peng Bo jin State Key Laboratory of Environment-friendly Energy Materials Southwest University of Science and TechnologyMianyang621010SichuanPR China

3,4-Dinitrofurazanfuroxan(DNTF),as a high-energy-density material,features good thermal stability and wide *** study aimed to elucidate the thermal decomposition mechanism of DNTF combined with nitrogen-rich compounds containing *** thermal stabilities of DNTF and its hybrid systems were investigated using differential thermal analysis/thermogravimetry(TG),vacuum stability test,and accelerating rate calorimetry under isothermal,non-isothermal,and adiabatic conditions,*** showed that the thermal stability and thermal safety of DNTF significantly decreased after combining with nitrogen-rich compounds containing *** results showed that the activation energy of the DNTF hybrid systems was significantly lower than that of *** TGIR was used to monitor the generation of fugitive gases during the thermal decomposition of the DNTF/5-aminotetrazole(5-ATZ)***,the nitrogen-rich molecules containing N-H interacted extensively with DNTF,and this interaction accelerated the thermal degradation of DNTF.

关键词： DNTF NeH rich Nitrogen compounds Advanced thermal decomposition peak

Identification of Protein Coding Regions of Rice Genes Using Alternative Spectral Rotation Measure and Linear Discriminant Analysis

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Genomics, Proteomics & Bioinformatics 2004年第3期2卷 167-173页

作者： jiao jin Department of Statistics and Financial Mathematics School of Mathematical SciencesBeijing Normal Uni-versityBeijing 100875 Beijing Genomics Institute Beijing 101300China

An improved method, called Alternative Spectral Rotation (ASR) measure, for predicting protein coding regions in rice DNA has been developed. The method is based on the Spectral Rotation (SR) measure proposed by Kotlar and Lavner, and its accuracy is higher than that of the SR measure and the Spectral Content (SC) measure proposed by Tiwari et al. In order to increase the identifying accuracy, we chose three di?erent coding characters, namely the asymmetric, purine, and stop-codon variables as parameters, and an approving result was presented by the method of Linear Discriminant Analysis (LDA).

关键词： Alternative Spectral Rotation measure DFT nonparametric fitting LDA

Design optimization of 3.9GHz fundamental power coupler for the SHINE project

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Nuclear Science and Techniques 2021年第11期32卷 174-190页

作者： zhen-Yu Ma jin-Fang Chen Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201204China

The third harmonic superconducting cryomodule is being designed for the Shanghai High repetition rate XFEL and Extreme light facility(SHINE)project,which is under *** contrast to the European X-ray Free Electron Laser(E-XFEL)project,the 3.9 GHz cryomodules in the SHINE project will operate in the continuous wave regime with higher radio frequency average power for both cavities and *** propose a 3.9 GHz fundamental power coupler with an adjustable antenna length,for satisfying the SHINE project ***,we describe the 3.9 GHz fundamental power coupler's design considerations and power requirements for various operating modes of the SHINE *** also present the results of the radio frequency simulation and optimization,including the studies on multipacting and thermal analysis of the proposed 3.9 GHz coupler.

关键词： 3.9 GHz fundamental power coupler Third harmonic cavity Superconducting cryomodule XFEL and extreme light facility(SHINE)Linac

Enhanced electrode kinetics and properties via anionic regulation in polyanionic Na_(3+x)V_(2)(PO_(4))_(3-x)(P_(2)O_(7))_(x) cathode material

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Green Energy & Environment 2022年第4期7卷 763-771页

作者： Mei-Yi Wang Xin-Xin Zhao jin-Zhi Guo Xue-jiao Nie zhen-Yi Gu Xu Yang Xing-Long Wu National&Local United Engineering Laboratory for Power Batteries Faculty of ChemistryNortheast Normal UniversityChangchunJilin130024China Key Laboratory for UV Light-Emitting Materials and Technology of Ministry of Education Northeast Normal UniversityChangchunJilin130024China

Mixing polyanion cathode materials are promising candidates for the development of next-generation batteries, owing to their structural robustness and low-volume changes, yet low conductivity of polyanion hinders their practical capacity. Herein, the anion-site regulation is proposed to elevate the electrode kinetics and properties of polyanionic cathode. Multivalent anion P_(2)O_(7)^(4-) is selected to substitute the PO_(4)^(3-) in Na_(3)V_(2)(PO_(4))_(3) (NVP) lattice and regulate the ratio of polyanion groups to prepare Na_(3+x)V_(2)(PO_(4))_(3-x)(P_(2)O_(7))_(x)(NVPP_(x), 0 ≤ x ≤ 0.15) *** optimal Na_(3.1)V_(2)(PO_(4))_(2.9)(P_(2)O_(7))_(0.1) (NVPP_(0.1)) material can deliver remarkably elevated specific capacity(104 mAh g^(-1) at 0.1 C, 60 mAh g^(-1) at 20 C, respectively), which is higher than those of NVP. Moreover, NVPP_(0.1) exhibits outstanding cyclic stability(91% capacity retention after 300 cycles at 1 C). Experimental analyses reveal that the regulation of anions improves the structure stability, increases the active Na occupancy in the lattice and accelerates the Na+migration kinetics. The strategy of anion-site regulation provides the researchers a reference for the design of new high-performance polyanionic materials.

关键词： Sodium-ion batteries Cathode Polyanion materials Anionic substitution Electrode kinetics

Error analysis and a new steering law design for spacecraft control system using SGCMGs

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Acta Mechanica Sinica 2011年第5期27卷 803-808页

作者： jin jin jing-Rui Zhang Zao-zhen Liu Beijing Institute of Technology School of Aerospace Engineering100081 Beijing China

Based on the singular value decomposition theory,this paper analyzed the mechanism of escaping/avoiding singularity using generalized and weighted singularity-robust steering laws for a spacecraft that uses single gimbal control moment gyros （SGCMGs） as the actuator for the attitude control *** expression of output-torque error is given at the point of singularity,proving the incompatible relationship between the gimbal rate and the output-torque *** method of establishing a balance between the gimbal rate and the output-torque error is discussed,and a new steering law is *** results show that the proposed steering law can effectively drive SGCMGs to escape away from singularities.

关键词： Single gimbal control moment gyros (SGCMGs) Attitude control Singularity analysis Steering law