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Modeling and Calculation of Impact Friction Caused by Corner Contact in Gear Transmission

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Chinese Journal of Mechanical Engineering 2014年第5期27卷 958-964页

作者： ZHOU Changjiang chen siyu National Engineering Research Center for High Efficiency Grinding Hunan University State Key Laboratory of High Performance Complex Manufacturing Central South University

Corner contact in gear pair causes vibration and noise,which has attracted many ***,teeth errors and deformation make it difficulty to determine the point situated at corner contact and study the mechanism of teeth impact friction in the current *** on the mechanism of corner contact,the process of corner contact is divided into two stages of impact and scratch,and the calculation model including gear equivalent error-combined deformation is established along the line of *** to the distributive law,gear equivalent error is synthesized by base pitch error,normal backlash and tooth profile modification on the line of *** combined tooth compliance of the first point lying in corner contact before the normal path is inversed along the line of action,on basis of the theory of engagement and the curve of tooth synthetic *** secondarily the equivalent error with the combined deflection,the position standard of the point situated at corner contact is *** the impact positions and forces,from the beginning to the end during corner contact before the normal path,are calculated *** to the above results,the lash model during corner contact is founded,and the impact force and frictional coefficient are quantified.A numerical example is performed and the averaged impact friction coefficient based on the presented calculation method is *** research obtains the results which could be referenced to understand the complex mechanism of teeth impact friction and quantitative calculation of the friction force and coefficient,and to gear exact design for tribology.

关键词： gear transmission corner contact oblique impact model impact friction frictional coefficient

A high frequency vibration compensation approach for ultrahigh resolution SAR imaging based on sinusoidal frequency modulation Fourier-Bessel transform

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Journal of Systems Engineering and Electronics 2023年第4期34卷 894-905页

作者： chen siyu WANG Yong CAO Rui School of Electronics and Information Engineering Harbin Institute of TechnologyHarbin 150001China

Ultrahigh resolution synthetic aperture radar(SAR)imaging for ship targets is significant in SAR imaging,but it suffers from high frequency vibration of the platform,which will induce defocus into SAR imaging *** this paper,a novel compensation method based on the sinusoidal frequency modulation Fourier-Bessel transform(SFMFBT)is proposed,it can estimate the vibration errors,and the phase shift ambiguity can be avoided via extracting the time frequency ridge *** constructing the corresponding compensation function and combined with the inverse SAR(ISAR)technique,well-focused imaging results can be *** simulation imaging results of ship targets demonstrate the validity of the proposed approach.

关键词： synthetic aperture radar(SAR) high frequency vibration compensation sinusoidal frequency modulation FourierBessel transform(SFMFBT)

An adaptive integration surface for predicting transonic rotor noise in hovering and forward flights

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Chinese Journal of Aeronautics 2019年第9期32卷 2047-2058页

作者： siyu chen Qijun ZHAO Yiyang MA National Key Laboratory of Rotorcraft Aeromechanics Nanjing University of Aeronautics and Astronautics

In this paper, a new permeable adaptive integration surface is developed in order to evaluate transonic rotor noise in accordance with FW-H_pds equations(Ffowcs Williams-Hawkings equations with penetrable data surface). Firstly, a nonlinear near-field solution is computed on the basis of Navier-Stokes equations, which is developed on moving-embedded grid *** solution calculated through the present CFD method is used as the input for acoustic calculations by FW-H_pds equations. Then, two criteria for constructing integration surfaces are established based on the analysis of the quadrupole source strength and the nonlinear characteristic.A new surface is determined adaptively by the pressure gradient or density in a given flowfield,eschewing the uncertainties associated with determining cylinder-shaped integration surfaces. For varying hover cases, transonic noises are simulated with new integration surfaces for a UH-1 model rotor. Furthermore, numerical results of the new integration surface derived from the density perturbation value conform better to experimental data than results derived from the pressure ***, the integration surface given by jrqj being 0.1, which is an applicable criterion obtained from hover cases, is used to predict transonic rotor noise in forward flight. The computational accuracy of the new integration surface method has been validated in predicting transonic rotor noise of an AH-1 model rotor at different advance ratios.

关键词： FW-H_pds equations Integration surface Navier–Stokes equations Rotor Transonic rotor noise

Emergency Local Searching Approach for Job Shop Scheduling

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Chinese Journal of Mechanical Engineering 2013年第5期26卷 918-927页

作者： ZHAO Ning chen siyu DU Yanhua School of Mechanical Engineering University of Science and Technology Beijing

Existing methods of local search mostly focus on how to reach optimal ***,in some emergency situations,search time is the hard constraint for job shop scheduling problem while optimal solution is not *** this situation,the existing method of local search is not fast *** paper presents an emergency local search(ELS) approach which can reach feasible and nearly optimal solution in limited search *** ELS approach is desirable for the aforementioned emergency situations where search time is limited and a nearly optimal solution is sufficient,which consists of three ***,in order to reach a feasible and nearly optimal solution,infeasible solutions are repaired and a repair technique named group repair is ***,in order to save time,the amount of local search moves need to be reduced and this is achieved by a quickly search method named critical path search(CPS).Finally,CPS sometimes stops at a solution far from the optimal *** order to jump out the search dilemma of CPS,a jump technique based on critical part is used to improve ***,the schedule system based on ELS has been developed and experiments based on this system completed on the computer of Intel Pentium(R) 2.93 *** experimental result shows that the optimal solutions of small scale instances are reached in 2 s,and the nearly optimal solutions of large scale instances are reached in 4 *** proposed ELS approach can stably reach nearly optimal solutions with manageable search time,and can be applied on some emergency situations.

关键词： emergency local search job shop scheduling problem schedule critical path critical constraint part

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On Communitarianism

学术界 2017年第9期 305-315页

作者： chen siyu Heilongjiang University Harbin Heilongjiang 150080

The advancem ent and developm ent of com m unitarianism is based on the criticizing and questioning of neoliberalism. C om m unitarianism addresses the m aintenance of collective interests,social justice and national interests,and it features an independent theoretical system w hich becom es the w estern 's im portant ideological theory against the new *** is of great significance to understand and grasp com m unitarianism deeply and correctly for the w estern social thought from the perspective of a com parative analysis of neoliberalism.

关键词：新自由主义国家利益西方社会 COM 集权

An intelligent task offloading algorithm(iTOA)for UAV edge computing network

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Digital Communications and Networks 2020年第4期6卷 433-443页

作者： Jienan chen siyu chen siyu Luo Qi Wang Bin Cao Xiaoqian Li The National Key Laboratory of Science and Technology on Communications University of Electronic Science and Technology of ChinaChengduSichuan611731China State Key Laboratory of Networking and Switching Technology Beijing University of Posts and TelecommunicationsBeijing100876China Department of Electrical and Electronic Engineering The University of Hong KongPokfulamHong Kong

Unmanned Aerial Vehicle(UAV)has emerged as a promising technology for the support of human activities,such as target tracking,disaster rescue,and ***,these tasks require a large computation load of image or video processing,which imposes enormous pressure on the UAV computation *** solve this issue,in this work,we propose an intelligent Task Offloading Algorithm(iTOA)for UAV edge computing *** with existing methods,iTOA is able to perceive the network’s environment intelligently to decide the offloading action based on deep Monte Calor Tree Search(MCTS),the core algorithm of Alpha *** will simulate the offloading decision trajectories to acquire the best decision by maximizing the reward,such as lowest latency or power *** accelerate the search convergence of MCTS,we also proposed a splitting Deep Neural Network(sDNN)to supply the prior probability for *** sDNN is trained by a self-supervised learning ***,the training data set is obtained from iTOA itself as its own *** with game theory and greedy search-based methods,the proposed iTOA improves service latency performance by 33%and 60%,respectively.

关键词： Unmanned aerial vehicles(UAVs) Mobile edge computing(MEC) Intelligent task offloading algorithm(iTOA) Monte Carlo tree search(MCTS) Deep reinforcement learning Splitting deep neural network(sDNN)

Effective Iterated Greedy Algorithm for Flow-Shop Scheduling Problems with Time lags

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Chinese Journal of Mechanical Engineering 2017年第3期30卷 652-662页

作者： Ning ZHAO Song YE Kaidian LI siyu chen school of mechanical engineering university of science and technology beijingBeijing 100083China

Flow shop scheduling problem with time lags is a practical scheduling problem and attracts many studies. Permutation problem（PFSP with time lags） is concentrated but non-permutation problem（non-PFSP with time lags） seems to be neglected. With the aim to minimize the makespan and satisfy time lag constraints, efficient algo- rithms corresponding to PFSP and non-PFSP problems are proposed, which consist of iterated greedy algorithm for permutation（IGTLP） and iterated greedy algorithm for non-permutation （IGTLNP）. The proposed algorithms are verified using well-known simple and complex instances of permutation and non-permutation problems with various time lag ranges. The permutation results indicate that the proposed IGTLP can reach near optimal solution within nearly 11% computational time of traditional GA approach. The non-permutation results indicate that the proposed IG can reach nearly same solution within less than 1% com- putational time compared with traditional GA approach. The proposed research combines PFSP and non-PFSP together with minimal and maximal time lag consideration, which provides an interesting viewpoint for industrial implementation.

关键词： Permutation Non-permutation Flow shopTime lags . Makespan Iterated greedy algorithm

Aerosol optical properties and its direct radiative forcing over Tibetan Plateau from 2006 to 2017

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Particuology 2023年第3期74卷 64-73页

作者： Hongru Bi siyu chen Dan Zhao Fuquan Lu Yu chen Yawen Guan Key Laboratory for Semi-Arid Climate Change of the Ministry of Education Lanzhou UniversityLanzhou730000China Key Laboratory of Land Surface Process and Climate Change in Cold and Arid Regions Northwest Institute of Eco-Environment and ResourcesLanzhou730000China

Studies on optical properties of aerosols can reduce the uncertainty for modelling direct radiative forcing(DRF)and improve the accuracy for discussing aerosols effects on the Tibetan Plateau(TP)*** study investigated the spatiotemporal variation of aerosol optical and microphysical properties over TP based on OMI and MERRA2,and assessed the influence of aerosol optical properties on DRF at NamCo station(30°46.44′N,90°59.31′E,4730 m)in the central TP from 2006 to 2017 based on a long measurement of AERONET and the modelling of SBDART *** results show that aerosol optical depth(AOD)exhibits obvious seasonal variation over TP,with higher AOD500nm(>0.75)during spring and summer,and lower value(<0.25)in autumn and *** aerosol concentrations show a fluctuated rising from 1980 to 2000,significant increasing from 2000 to 2010 and slight declining trend after *** on sensitivity experiments,it is found that AOD and single scattering albedo(SSA)have more important impact on the DRF compared withαvalues and *** AOD440nm increases by 60%,DRF at the TOA and ATM is increased by 57.2%and 60.2%,*** SSA440nm increases by 20%,DRF at the TOA and ATM decreases by 121%and 96.7%,respectively.

关键词： Direct radiative forcing Aerosol optical depth Single scattering albedo Santa Barbara DISORT Atmospheric Radiative Transfer Model Tibetan plateau

Discovery and Geological Significance of an Indosinian(ca.244 Ma)Metamorphic Event in the Langshan Area,Western Inner Mongolia,China:New Evidence from Zircon LA-ICP-MS U-Pb Dating

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Journal of Earth Science 2022年第4期33卷 993-1006页

作者： Yan Yan Runmin Peng siyu chen Shuangfei Li School of Earth Sciences and Resources China University of GeosciencesBeijing 100083China School of Earth and Space Sciences Peking UniversityBeijing 100871China No.8Institute of Geology and Mineral Resources of Shandong Province Rizhao 276826China

The Langshan Group is an important constituent of the Precambrian metamorphic rocks in the Langshan *** accurate determination of its metamorphic age is of great scientific significance for the further study of the Precambrian geological evolution in the *** remain regarding the metamorphism and deformation overprinting of the Langshan *** paper presents a detailed study comprising a field geological investigation,petrological observations,and zircon U-Pb aging of garnet-bearing mica quartz schists in the BangBang *** result of detrital zircon U-Pb dating from the metamorphosed volcanic sedimentary rock series and geological investigation of the garnet-bearing mica quartz schists suggest the strata formed in the *** results from cathodoluminescence(CL)image analysis and U-Pb dating of zircons indicate a large number of metamorphic zircons exist in the garnet-bearing mica quartz *** metamorphic overgrowth rims of zircon from two samples were analyzed by *** ^(206)Pb/^(238)U weighted average age of ca.244 Ma of the zircon metamorphism rims represents the timing of Indosinian greenschist-amphibolite facies metamorphism in the Langshan area,which may be in response to the collision-type orogeny of the North China and Siberian plates in the Late ***-intermediate magmatic intrusive activities occurred in the Langshan area,and metamorphic events developed at the same time or at a later stage during the closure of the Paleo-Asian Ocean.

关键词： Langshan Group Indosinian metamorphic event zircon U-Pb dating Langshan Orogenic Belts