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Mission segment division of the whole aeroengine loading spectrum based on flight actions

Chinese Journal of Aeronautics 2022年第2期35卷 164-174页

作者： Yu jin Zhigang SUN Yingdong SONG Xin LIN Xuming niu Junjie DING Jiangsu Province Key Laboratory of Aerospace Power System College of Energy and Power EngineeringNanjing University of Aeronautics and AstronauticsNanjing 210016China Key Laboratory of Aero-engine Thermal Environment and StructureMinistry of Industry and Information TechnologyNanjing 210016China State Key Laboratory of Mechanics and Control Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China

This paper studies on a division method of the whole aeroengine loading spectrum flight mission segment and rotor speed mission segment,which is based on the actual flight actions and related to the flight operations of aeroengine and is suitable for the variable-speed aeroengines such as turbojet and *** the research,the aeroengine loading spectrum operation-related mission segments can be divided,which can provide important data basis for the life research on the structures which are sensitive to flight maneuver(such as the main shaft,large gearbox and installation section),lay a foundation for the simulation,compilation and prediction of the whole aeroengine loading ***,based on the summary of basic flight actions in actual flight,the division of flight mission segment was realized by ***,the aeroengine rotor speed mission segments,associated with flight actions and missions,were divided based on the flight mission segment division ***,the efficiency and accuracy of the mission segment division results were verified by adopting measured loading spectrum ***,the characteristics of speed mission segment division results were compared and analyzed in tables and *** comparison results show that the characteristics of similar speed mission segments are similar,while the characteristics of different speed mission segments are *** the shapes of similar mission segments vary to the change of flight actions and operations,which can reflect the operation-related feature of the segments.

关键词： Aircraft engine Flight mission segment Mission segment division Rotor speed mission segment Spectrum analysis

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SYMBOLIC COMPUTATION FOR THE QUALITATIVE THEORY OF DIFFERENTIAL EQUATIONS

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Acta Mathematica Scientia 2022年第6期42卷 2478-2504页

作者： Bo HUANG wei niu Dongming WANG LMIB-School of Mathematical Sciences Beihang UniversityBeijing 100191China Ecole Centrale de Pekin Beihang UniversityBeijing 100191China Beihang Hangzhou Innovation Institute Yuhang Hangzhou 310051China Centre National de la Recherche Scientifique 75794 Paris Cedea 16France

This paper provides a survey on symbolic computational approaches for the analysis of qualitative behaviors of systems of ordinary differential equations,focusing on symbolic and algebraic analysis for the local stability and bifurcation of limit cycles in the neighborhoods of equilibria and periodic orbits of the systems,with a highlight on applications to computational biology.

关键词： biological systems center-focus limit cycles qualitative analysis symbolic computation

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Protective effect of glutamine on intestinal injury and bacterial community in rats exposed to hypobaric hypoxia environment

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World Journal of Gastroenterology 2014年第16期20卷 4662-4674页

作者： Chun-Lan Xu Rui Sun Xiang-jin Qiao Cui-Cui Xu Xiao-Ya Shang wei-Ning niu The Key Laboratory for Space Bioscience and Biotechnology School of Life SciencesNorthwestern Polytechnical University

AIM: To investigate the protective effect of glutamine (Gln) on intestinal injury and the bacterial community in rats exposed to hypobaric hypoxia environment.

关键词： Hypobaric hypoxia Glutamine Intestinal mucosa Immunomodulation Bacterial community

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Numerical simulation of the factors influencing dust in drilling tunnels:Its application

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Mining Science and Technology 2011年第1期21卷 11-15页

作者： niu wei Jiang Zhongan Tian Dongmei Key Laboratory of Ministry of Education for High Efficiency Exploitation and Safety of Metal Mine. Beijing University of Sdence and Technology Beijing 100083 China

Gas-solid two-phase flow theory was used to predict dust distribution and movement at the working face of a *** software package FLUENT was used to numerically simulate dust motion and the results were compared to observed *** simulation agrees with the data taken from an actual working face,which confirms the choice of mathematical model and numerical simulation method. Using the model we predict a set of conditions optimum for reducing dust concentrations at the mine working face.

关键词： Drivage working faceDust concentrationThe gas-solid two-phase flowVentilation method

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A Novel Evaluation Strategy to Artificial Neural Network Model Based on Bionics

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Journal of Bionic Engineering 2022年第1期19卷 224-239页

作者： Sen Tian jin Zhang Xuanyu Shu Lingyu Chen Xin niu You Wang School of Mathematics and Statistics Hunan Normal UniversityChangsha410081China College of Information Science and Engineering Hunan Normal UniversityChangsha410081China School of Computer and Communication Engineering Changsha University of Science and TechnologyChangsha410114China Key Laboratory of Industrial Control Technology Zhejiang UniversityHangzhou310058China Science and Technology on Parallel and Distributed Laboratory College of ComputerNational University of Defense TechnologyChangsha410199China Key Laboratory of Industrial Control Technology Institute of Cyber Systems and ControlZhejiang UniversityHangzhou310027China

With the continuous deepening of Artificial Neural Network(ANN)research,ANN model structure and function are improving towards diversification and ***,the model is more evaluated from the pros and cons of the problem-solving results and the lack of evaluation from the biomimetic aspect of imitating neural networks is not inclusive ***,a new ANN models evaluation strategy is proposed from the perspective of bionics in response to this problem in the ***,four classical neural network models are illustrated:Back Propagation(BP)network,Deep Belief Network(DBN),LeNet5 network,and olfactory bionic model(KIII model),and the neuron transmission mode and equation,network structure,and weight updating principle of the models are analyzed *** analysis results show that the KIII model comes closer to the actual biological nervous system compared with other models,and the LeNet5 network simulates the nervous system in ***,evaluation indexes of ANN are constructed from the perspective of bionics in this paper:small-world,synchronous,and chaotic ***,the network model is quantitatively analyzed by evaluation indexes from the perspective of *** experimental results show that the DBN network,LeNet5 network,and BP network have synchronous *** the DBN network and LeNet5 network have certain chaotic characteristics,but there is still a certain distance between the three classical neural networks and actual biological neural *** KIII model has certain small-world characteristics in structure,and its network also exhibits synchronization characteristics and chaotic *** with the DBN network,LeNet5 network,and the BP network,the KIII model is closer to the real biological neural network.

关键词： Artificial neural network(ANN) Back Propagation(BP)network Deep Belief Network(DBN) LeNet5 network Olfactory bionic model(KIII model) Small world Chaos Synchronous

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A density functional theory study of methane activation on MgO supported Ni_(9)M_(1) cluster:role of M on C-H activation

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Frontiers of Chemical Science and Engineering 2022年第10期16卷 1485-1492页

作者： Juntian niu Haiyu Liu Yan jin Baoguo Fan Wenjie Qi jingyu Ran College of Electrical and Power Engineering Taiyuan University of TechnologyTaiyuan 030024China Key Laboratory of Advanced Manufacturing Technology for Automobile Parts Ministry of EducationChongqing University of TechnologyChongqing 400050China Key Laboratory of Low-grade Energy Utilization Technologies and Systems Ministry of EducationChongqing UniversityChongqing 400044China

Methane activation is a pivotal step in the application of natural gas converting into high-value added chemicals via methane steam/dry reforming *** element was found to be the most widely used *** present work,methane activation on MgO supported Ni–M(M=Fe,Co,Cu,Pd,Pt)cluster was explored through detailed density functional theory calculations,compared to pure Ni ***_(4)adsorption on Cu promoted Ni cluster requires overcoming an energy of 0.07 eV,indicating that it is slightly endothermic and unfavored to occur,while the adsorption energies of other promoters M(M=Fe,Co,Pd and Pt)are all higher than that of pure Ni *** role of M on the first C–H bond cleavage of CH_(4)was *** elements of the same period in Ni cluster,such as Fe,Co and Cu,for C–H bond activation follows the trend of the decrease of metal atom *** a result,Ni–Fe shows the best ability for C–H bond *** addition,doping the elements of the same family,like Pd and Pt,for CH_(4)activation is according to the increase of metal atom ***,C–H bond activation demands a lower energy barrier on Ni–Pt *** illustrate the adsorptive dissociation behaviors of CH_(4)at different Ni–M clusters,the Mulliken atomic charge was *** general,the electron gain of CH_(4)binding at different Ni–M clusters follows the sequence of Ni–Cu(–0.02 e)

关键词： CH_(4) dissociation Ni-M C-H bond activation charge transfer

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Study of electrospray ionization tandem mass spectrometry of the benzofuranone compounds

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Chinese Chemical Letters 2008年第3期19卷 324-328页

作者： Zhan Qi niu Yu Min Sun Feng niu Jian Han Da wei Chen School of Pharmacy of Shenyang Pharmaceutical University Shenyang 110016 China ShiJiaZhuang Pharnta Group NBP Pharmaceutical Co. Ltd. Shijiazhuang 052160 China Department of Pharmaceutical Engineering School of Chemical EngineeringDalian University of Technology Dalian 116000 China Department of Natural Medicines School of Pharmaceutical Sciences Peking Universio Health Science Center Beijing 10008.3 China

A detailed analysis of benzofuranone compounds under multiple tandem mass spectrometry （ESI-MS^n） conditions is reported. Element composition data of the fragment ions were obtained with the aid of comparison of the multiple tandem mass spectra of four compounds, and the structures of which are identical except for some substituted groups or epimers or cis-trans-isomers. Attempts have been made to provide rational pathways for the formation of the fragment ions from these protonated compounds. And the structure-fragmentation relationships will facilitate the characterization of the structures of other analogs.

关键词： ESI-MS^n Benzofuranones Epimer: cis-trans-Isomer

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3D T1-weighted black blood sequence at 3.0 Tesla for the diagnosis of cervical artery dissection

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Stroke & Vascular Neurology 2016年第3期1卷 140-146页

作者： Yun Luo Zhen-Ni Guo Peng-Peng niu Yang Liu Hong-wei Zhou Hang jin Yi Yang Stroke Center Neuroscience CenterDepartment of NeurologyThe First Hospital of Jilin UniversityChangchunChina Department of Radiology The First Hospital of Jilin UniversityChangchunChina

Objective:We aimed to investigate the value of threedimensional(3D)T1 volumetric isotropic turbo spin echo acquisition(VISTA)in the diagnosis of cervical artery dissection(CAD).Methods:We prospectively included patients who were suspected as having a CAD within 1 month of *** T1 VISTA,the diagnosis of the dissection was based on the presence of intramural high-signal,intimal flap,double lumen and aneurysmal *** final diagnosis of dissection was based on the clinical history,physical examination,and all of the imaging ***:A total of 46 patients were included in this *** final diagnosis of CAD was made for 21 *** of dissection was made for 20 of the 21 patients after assessing T1 VISTA.A definitive diagnosis of dissection was not made for 5 patients(including 3 patients with digital subtraction angiography)before the T1 VISTA *** sensitivity and specificity for T1 VISTA were 95.2%(95%CI,76.2%to 99.9%)and 100%(95%CI,86.3%to 100%),*** agreement between the two researchers for T1 VISTA for diagnosis of CAD was very good(k=0.91).For patients without acute artery occlusion,all of them had a definite conclusion with or without dissection by T1 VISTA(n=29).However,for 17 patients with acute artery occlusion,the possibility of dissection could not be excluded for 6 of them by T1 VISTA(p=0.001).Conclusions:3D T1 VISTA at 3.0 Tesla was useful in the diagnosis of acute ***,for some patients with total occlusion of the artery without typical imaging features of dissection,the unequivocal distinction between intramural haematoma and intraluminal thrombus may be not adequate by T1 VISTA *** studies should investigate whether a follow-up scan,a contrast-enhanced imaging or an optimal VISTA technique could be useful.

关键词： diagnosis alone VISTA

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An Overview on Backscatter Communications

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Journal of Communications and Information Networks 2019年第2期4卷 1-14页

作者： jin-Ping niu Geoffrey Ye Li Shaanxi International Joint Research Centre for the Battery-Free Internet of Things School of Information and TechnologyNorthwest UniversityXi’anShaanxi 710127China School of Electrical and Computer Engineering Georgia Institute of TechnologyAtlantaGA30332USA

As a key low-power communication tech-nique,backscatter communications exploits the reflected or backscattered signals to transmit data,where the backscattered signals can be the reflection of ambient radio frequency(RF)signals,the RF signals from the dedicated carrier emitter or the signal photons in the non-classical quantum entangled pairs,*** the past 70 years,various kinds of backscatter communication systems have been developed,which will enable the low-power communications as required in the Internet of things(IoTs)and green *** article provides a historical view on the development and the research achievements on backscatter communications,including the fundamental principles,the applications,the challenges,and the potential research *** article will benefit the researchers and engineers concerning the area of backscatter communications,especially for applications in IoTs.

关键词： backscatter backscatter communications energy harvesting IoTs

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2,3-Dimercaptosuccinic acid self-assembled gold electrode for the simultaneous determination of epinephrine and dopamine

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Chinese Chemical Letters 2009年第2期20卷 221-224页

作者： wei Jun Kang Ling Mei niu Li Ma School of Public Health Hebei Medical University Shijiazhuang 050017 China

Simultaneous determination of epinephrine （EP） and dopamine （DA） at 2,3-dimercaptosuccinic acid （DMSA） modified electrode was studied. The oxidation peaks of the mixture of EP and DA appeared at the same potential, but the cathodic peak currents were only linear to the concentration of DA, whereas the anodic peak currents were equal to the sum of individual anodic peak currents of EP and DA. Therefore, a novel electrochemical method for the simultaneous determination of EP and DA at a DMSA modified electrode （DMSA/Au electrode） by cyclic voltammetry was established. The DMSA self-assembled electrode showed good sensitivity, selectivity and stability and could be used to determine DA and EP, simultaneously, in the real application with satisfactory results.

关键词： 2,3-Dimercaptosuccinic acid Simultaneous determination Dopamine Epinephrine

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