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| 1 | Analyses of hot and humid weather in Beijing city in summer and its dynamical identification显示文摘The circulation, hygrothermal property and moisture transport character of typical hot and humid weather were analyzed in Beijing areas from July 30 to August 4, 2002. It was pointed out that, under the control of subtropical anticyclone which stretches to the west and north, downdraft suppresses the lifting of lower-troposphere moisture, which makes moisture keep in the lower troposphere. That is the direct reason causing hot and humid weather. Considering the non-uniformity saturated character in real atmosphere, generalized moist potential vorticity (GMPV) equation is derived by the introduction of generalized moist potential temperature concept. The analysis of GMPV shows that negative GMPV anomaly occurs in the lower troposphere. It has indicative sense to hot and humid weather. Thus, the GMPV anomaly can be utilized to identify this kind of weather and to make a short-term prediction. | GAO Shouting ZHOU Yushu LEI Ting SUN Jianhua | 2005 | Science China Earth Sciences2005，48，z2： | 30 |
| 2 | A review of aerial manipulation of small-scale rotorcraft unmanned robotic systems显示文摘Small-scale rotorcraft unmanned robotic systems(SRURSs) are a kind of unmanned rotorcraft with manipulating devices. This review aims to provide an overview on aerial manipulation of SRURSs nowadays and promote relative research in the future. In the past decade, aerial manipulation of SRURSs has attracted the interest of researchers globally. This paper provides a literature review of the last 10 years(2008–2017) on SRURSs, and details achievements and challenges. Firstly, the definition, current state, development, classification, and challenges of SRURSs are introduced. Then, related papers are organized into two topical categories: mechanical structure design, and modeling and control. Following this, research groups involved in SRURS research and their major achievements are summarized and classified in the form of tables. The research groups are introduced in detail from seven parts. Finally, trends and challenges are compiled and presented to serve as a resource for researchers interested in aerial manipulation of SRURSs. The problem,trends, and challenges are described from three aspects. Conclusions of the paper are presented,and the future of SRURSs is discussed to enable further research interests. | Xilun DING Pin GUO Kun XU Yushu YU | 2019 | Chinese Journal of Aeronautics2019，32，1： | 18 |
| 3 | Model predictive control and improved low-pass filtering strategies based on wind power fluctuation mitigation显示文摘The rapid development of renewable energy sources such as wind power has brought great challenges to the power grid. Wind power penetration can be improved by using hybrid energy storage(ES) to mitigate wind power fluctuation. We studied the strategy of smoothing wind power fluctuation and the strategy of hybrid ES power distribution. Firstly, an effective control strategy can be extracted by comparing constant-time low-pass filtering(CLF), variable-time low-pass filtering(VLF), wavelet packet decomposition(WPD), empirical mode decomposition(EMD) and model predictive control algorithms with fluctuation rate constraints of the identical grid-connected wind power. Moreover, the mean frequency of ES as the cutoff frequency can be acquired by the Hilbert Huang transform(HHT), and the time constant of filtering algorithm can be obtained. Then, an improved low-pass filtering algorithm(ILFA) is proposed to achieve the power allocation between lithium battery(LB) and supercapacitor(SC), which can overcome the over-charge and over-discharge of ES in the traditional low-pass filtering algorithm(TLFA). In addition, the optimized LB and SC power are further obtained based on the SC priority control strategy combined with the fuzzy control(FC) method. Finally, simulation results show that wind power fluctuation can be effectively suppressed by LB and SC based on the proposed control strategies, which is beneficial to the development of wind and storage system. | Yushu SUN Xisheng TANG Xiaozhe SUN Dongqiang JIA Zhihuang CAO Jing PAN Bin XU | 2019 | Journal of Modern Power Systems and Clean Energy2019，7，3： | 13 |
| 4 | Analysis of 1/2 sub-harmonic resonance in a maneuvering rotor system显示文摘This paper focuses on the 1/2 sub-harmonic resonance of an aircraft’s rotor system under hovering flight that can be modeled as a maneuver load G in the equations of motion.The effect on the rotor system is analyzed by using theoretical methods.It is shown that the sub-harmonic resonance may occur due to maneuvering flight conditions.The larger the eccentricity E and the maneuver load G,the greater the sub-harmonic resonance.The effects of nonlinear stiffness,damping of the system,maneuver load,and eccentricity on the sub-harmonic resonance region in parameter planes are also investigated.Bifurcation diagrams of the analytical solutions are in good agreement with that of the numerical simulation solutions.These results will contribute to the understanding of the nonlinear dynamic behaviors of maneuvering rotor systems. | HOU Lei CHEN YuShu | 2014 | Science China(Technological Sciences)2014，57，1： | 10 |
| 5 | Influencing factors of the dynamic hysteresis in varying compliance vibrations of a ball bearing显示文摘We focus on the hysteretic characteristics of the varying compliance(VC) principal resonance in a ball bearing. The branches of the periodic VC response are traced by the harmonic balance method and the alternating frequency/time domain technique(HB-AFT) embedding Arc-length continuation, and the stability of these solutions is investigated by using Floquet theory. We find that the resonant response displays a swallow-tail structure due to the coupling nonlinearities between the Hertzian contact and the bearing clearance, which differs from the soft hysteresis of the non-loss Hertzian contact resonances. Furthermore, we find that period-1 VC branch cannot completely characterize the response of the system for a large bearing clearance, because multiple instability regions may occur from the cyclic fold, the secondary Hopf bifurcations, supercritical and subcritical period doubling bifurcations, in which case co-existences of period-1, period-2, and even quasi-periodic VC motions emerge in the hysteretic resonant range. | ZHANG ZhiYong CHEN YuShu LI ZhongGang | 2015 | Science China(Technological Sciences)2015，58，5： | 10 |
| 6 | Cascading failure analysis of power flow on wind power based on complex network theory显示文摘Cascading failure is a potential threat in power systems with the scale development of wind power,especially for the large-scale grid-connected and long distance transmission wind power base in China.This introduces a complex network theory(CNT)for cascading failure analysis considering wind farm integration.A cascading failure power flow analysis model for complex power networks is established with improved network topology principles and methods.The network load and boundary conditions are determined to reflect the operational states of power systems.Three typical network evaluation indicators are used to evaluate the topology characteristics of power network before and after malfunction including connectivity level,global effective performance and percentage of load loss(PLL).The impacts of node removal,grid current tolerance capability,wind power instantaneous penetrations,and wind farm coupling points on the power grid are analyzed based on the IEEE 30 bus system.Through the simulation analysis,the occurrence mechanism and main influence factors of cascading failure are determined.Finally,corresponding defense strategies are proposed to reduce the hazards of cascading failure in power systems. | Yushu SUN Xisheng TANG | 2014 | Journal of Modern Power Systems and Clean Energy2014，2，4： | 10 |
| 7 | Bifurcation analysis on full annular rub of a nonlinear rotor system显示文摘In this paper, analytical and numerical studies are carried out on the full annular rub motions of a nonlinear Jeffcott rotor. Transition sets of the synchronous full annular rub are given with the help of averaging method and constraint bifurcation theory to discuss the effects of system parameters on jump phenomena. Routh-Hurwitz criteria are employed to analyze the stability of synchronous full annular rub solution and determine the boundaries of static and Hopf bifurcations. Finally, the response and onset condition of reverse dry whip are investigated numerically, and at the same time, the influences of rotor parameters and rotation speed on the characteristics of the rotor response are investigated. | ZHANG HuaBiao CHEN YuShu | 2011 | Science China(Technological Sciences)2011，54，8： | 9 |
| 8 | Super-harmonic responses analysis for a cracked rotor system considering inertial excitation显示文摘In this paper, an investigation on the nonlinear vibration, especially on the super-harmonic resonances, in a cracked rotor system is carried out to provide a novel idea for the detection of crack faults in rotor systems. The motion equations of the system are formulated with the consideration of the additional excitation from an inertial environment as well as the forced excitation of the rotor unbalance. By using the harmonic balance method, the analytical solutions of the equations with four orders of harmonic exponents are obtained to analyze the nonlinear response of the system. Then through numerical calculations, the vibration responses affected by system parameters including the inertial excitation, the forced excitation, the crack and damping factors are investigated in detail. The results show that the occurrence of the super-harmonic resonances of the rotor system is due to the interaction between crack breathing and the inertial excitation. Correspondingly, the super-harmonic responses are significantly affected by the inertial excitation and the crack stiffness(or depth). The rotor unbalance, however, does not make apparent effects on the super-harmonic responses. Consequently, the super-harmonic resonances peaks can be viewed as an identification signal of the crack fault due to the application of the inertial excitation. By utilizing the inertial excitation, the super-harmonic response signals in rotor systems with early crack faults can be amplified and detected more easily. | HOU Lei CHEN YuShu | 2015 | Science China(Technological Sciences)2015，58，11： | 9 |
| 9 | Structural Dimension Optimization of Robotic Belt Grinding System for Grinding Workpieces with Complex Shaped Surfaces Based on Dexterity Grinding Space显示文摘为了改进机器的带磨擦的磨擦质量,为有建筑群的细工品的系统塑造了表面,磨点的灵巧的新概念和磨空格的灵巧被建议,他们的数学描述被定义。影响磨空间的灵巧的因素被分析。并且决定磨空间的必要灵巧的一个方法被建议。把方法基于粒子群优化(PSO ) ,优化磨擦机器人的策略关于磨擦车轮的结构的尺寸和位置被提出获得磨空间的必要灵巧。最后,磨天线引擎片,奉献 PPPRRR (P:棱柱的 R:旋转) 磨擦机器人关于磨擦车轮的结构的尺寸和位置用上述策略被优化。根据模拟结果,如果片被放在磨空间的灵巧以内,仅仅一 gripper 和一磨擦机器被需要磨它的建筑群塑造的表面。 | GAO Zhihui LAN Xiaodong BIAN Yushu | 2011 | Chinese Journal of Aeronautics2011，24，3： | 9 |
| 10 | Singular analysis of bifurcation systems with two parameters显示文摘有二个参数的动态系统的分叉性质在这份报纸被调查。设置的转变的定义被建议,并且开发的途径被用来与非线性的反馈控制器调查非线性的强迫的未击中的系统的动态特征。整个参量的飞机被转变集合划分成几个坚持的区域,然后在不同坚持的区域的分叉图被获得。关键词二个参数 - 分叉 - 单个分析工程被中国(10632040 ) 的国家自然科学基础支持。 | Zhaohong Qin Yushu Chen | 2010 | Acta Mechanica Sinica2010，26，3： | 8 |
| 11 | Overview of Energy Storage in Renewable Energy Power Fluctuation Mitigation显示文摘The integration of renewable energy,such as PV and wind power,has exerted great impacts on the power system with its rapid development.If the corresponding energy storage system is configured,the power system could be able to hold a higher proportion of renewable energy.Focusing on energy storage application for the output fluctuation mitigation of renewable energy,this paper first analyses the reason for renewable energy power fluctuation mitigation from the four aspects of frequency,unit ramp,low frequency oscillation and cascading failure.In addition,the fluctuation rate standard of grid-connected renewable energy,the energy storage type and the mitigation topology are introduced.Then a summary and analysis on mitigation strategy and hybrid energy storage allocation strategy are presented.Finally,the demonstration application and development trend of energy storage are analyzed to provide reference for the promotion of energy storage in renewable energy. | Yushu Sun Zhenxing Zhao Min Yang Dongqiang Jia Wei Pei Bin Xu | 2020 | CSEE Journal of Power and Energy Systems2020，6，1： | 8 |
| 12 | Bifurcation analysis for vibrations of a turbine blade excited by air flows显示文摘模仿汽轮机片和即将来临的空气流动的液体结构相互作用(FSI ) 的一个减少的 three-degree-of-freedom 模型被建议。运动的方程由联合弯曲和片以及代表的货车 der Pol 摆动的扭转组成液体变化时间。1:1 系统的内部回声与多重规模方法被分析,并且调整方程被导出。二参数的分叉图被计算。包括 detuning 参数和减少的频率,系统参数的效果在结构和液体的回答上被调查。分叉曲线被计算,稳定性被检验 Jacobian 矩阵的特征值决定。结果显示包括僵绳的不变的解决方案的富有的动态现象 -- 节点和 Hopf 分叉能发生在某些参数条件下面。不稳定的答案发生的参数区域应该被避免保留片的安全操作。分析答案被直接数字的模拟验证。 | WANG Dan CHEN YuShu HAO ZhiFeng CAO QingJie | 2016 | Science China(Technological Sciences)2016，59，8： | 7 |
| 13 | Variability of soil organic carbon reservation capability between coastal salt marsh and riverside freshwater wetland in Chongming Dongtan and its microbial mechanism显示文摘Two representative zones in Chongming Dongtan which faced the Yangtze River and East China Sea respectively were selected to study the variability of soil organic carbon (SOC) reservation capability between coastal wetland and riverside wetland in the Chongming Dongtan wetland as well as its mechanism by analyzing soil characteristics and plant biomass.The results showed the SOC content of riverside wetland was only 48.61% (P=0.000 < 0.05) that of coastal wetland.As the organic matter inputs from plant litter of the coastal wetland and riverside wetland were approximately the same,the higher soil microbial respiration (SMR) of riverside wetland led to its lower SOC reservation capability.In the riverside wetland,the high soil microbial biomass,higher proportion of β-Proteobacteria,which have strong carbon metabolism activity and the existence of some specific aerobic heterotrophic bacteria such as Bacilli and uncultured Lactococcus,were the important reasons for the higher SMR compared to the coastal wetland.There were additional differences in soil physical and chemical characteristics between the coastal wetland and riverside wetlands.Path analysis of predominant bacteria and microbial biomass showed that soil salinity influenced β-Proteobacteria and microbial biomass most negatively among these physical and chemical factors.Therefore the low salinity of the riverside area was suitable for the growth of microorganisms,especially β-Proteobacteria and some specific bacteria,which led to the high SMR and low SOC reservation capability when compared to the coastal area. | Yu Hu Yanli Li Lei Wang Yushu Tang Jinhai Chen Xiaohua Fu Yiquan Le Jihua Wu | 2012 | Journal of Environmental Sciences2012，24，6： | 7 |
| 14 | COUPLING EFFECT OF FLEXIBLE JOINT AND FLEXIBLE LINK ON DYNAMIC SINGULARITY OF FLEXIBLE MANIPULATOR显示文摘The coupling effect of the flexible joint and the flexible link on the dynamic singularity of the flexible manipulator is addressed. Firstly,the dynamic equations of a flexible manipulator with a flexible joint and a flexible link are derived. Secondly,the relationship and property between the flexible joint and the flexible link are analyzed. It shows that the flexible joint's amplitude will increase abruptly,thereby the dynamic singularity occurs if the frequency of a flexible joint is near or equal to some natural frequency of a flexible link. Finally,some numerical simulations which will verify the correctness of the theoretical analysis,are carried out. The results are fundamental for the design of a flexible manipulator and for the avoidance of the dynamic singularity. | GAO Zhihui YUN Chao BIAN Yushu | 2008 | Chinese Journal of Mechanical Engineering2008，21，1： | 6 |
| 15 | Periodic response analysis of a misaligned rotor system by harmonic balance method with alternating frequency/time domain technique显示文摘A dynamic model is established for an offset-disc rotor system with a mechanical gear coupling, which takes into consideration the nonlinear restoring force of rotor support and the effect of coupling misalignment. Periodic solutions are obtained through harmonic balance method with alternating frequency/time domain(HB-AFT) technique, and then compared with the results of numerical simulation. Good agreement confirms the feasibility of HB-AFT scheme. Moreover, the Floquet theory is adopted to analyze motion stability of the system when rotor runs at different speed intervals. A simple strategy to determine the monodromy matrix is introduced and two ways towards unstability are found for periodic solutions: the period doubling bifurcation and the secondary Hopf bifurcation. The results obtained will contribute to the global response analysis and dynamic optimal design of rotor systems. | LI HongLiang CHEN YuShu HOU Lei ZHANG ZhiYong | 2016 | Science China(Technological Sciences)2016，59，11： | 6 |
| 16 | Bifurcation and chaos of the bladed overhang rotor system with squeeze film dampers显示文摘To study the nonlinear dynamic behavior of the bladed overhang rotor system with squeeze film damper (SFD), a blade-overhang rotor-SFD model is formulated using the lumped mass method and the Lagrange approach. The cavitated short bearing model is employed to describe the nonlinear oil force of the SFD. To reduce the scale of the nonlinear coupling system, a set of orthogonal transformations is employed to decouple the one nodal diameter equations of blades, which are coupled with the dy- namical equations of the rotor, with other equations of blades. In this way, the original system with 16+4n (n≥3) degrees of freedom (DoF) is reduced to a system with 24 DoF only. Then the parametric excitation terms in the blade-overhang rotor-SFD model are simplified in terms of periodic transforma- tions. The coupling equations are numerically solved and the solutions are used to analyze the dy- namic behavior of the system in terms of the bifurcation diagram, whirl orbit, Poincaré map and spec- trum plot. A variety of motion types are found such as multi-periodic, quasi-periodic, and chaotic mo- tions. Moreover, the typical nonlinear dynamic evolutions including the periodic-doubling bifurcation and reverse bifurcation are noted. It is noticed that there exist apparent differences in the dynamic behavior between the blade-overhang rotor-SFD models without and with considering the effect of blades. | CAO DengQing WANG LiGang CHEN YuShu HUANG WenHu | 2009 | Science China(Technological Sciences)2009，52，3： | 5 |
| 17 | Quaternion-based Nonlinear Trajectory Tracking Control of a Quadrotor Unmanned Aerial Vehicle显示文摘At present, most controllers of quadrotor unmanned aerial vehicles(UAVs) use Euler angles to express attitude. These controllers suffer a singularity problem when the pitch angle is near 90?, which limits the maneuverability of the UAV. To overcome this problem, based on the quaternion attitude representation, a 6 degree of freedom(DOF) nonlinear controller of a quadrotor UAV is designed using the trajectory linearization control(TLC) method. The overall controller contains a position sub-controller and an attitude sub-controller. The two controllers regulate the translational and rotational motion of the UAV, respectively. The controller is improved by using the commanded value instead of the nominal value as the input of the inner control loop. The performance of controller is tested by simulation before and after the improvement, the results show that the improved controller is better. The proposed controller is also tested via numerical simulation and real flights and is compared with the traditional controller based on Euler angles. The test results confirm the feasibility and the robustness of the proposed nonlinear controller. The proposed controller can successfully solve the singularity problem that usually occurs in the current attitude control of UAV and it is easy to be realized. | ZHA Changliu DING Xilun YU Yushu WANG Xueqiang | 2017 | Chinese Journal of Mechanical Engineering2017，30，1： | 5 |
| 18 | 过量受照人员细胞遗传学随访观察显示文摘本文报道了一次受γ射线过量(10.0~46.8cGy)照射人员照后15~26年细胞遗传学随访结果。其中,染色体畸变分析56例,微核检查直接法22例,常规培养法42例,并设有相应的对照组。结果表明,染色体畸变率和两种方法的微核率受照组都明显高于对照组,差异有显著性意义,但染色体畸变率及微核率与受照剂量的相关关系已不存在。 | Bai Yushu (Laboratory of Industrial Hygiene,Ministry of Health,Beijing 100088) | 1997 | 中国辐射卫生1997，6，2： | 5 |
| 19 | Contribution of cloud condensate to surface rainfall process显示文摘到表面降雨过程的云冷凝物的贡献在热带传送对流的一条寿命被调查基于时时从解决模拟的二维的云的数据,模型被大规模垂直速度强迫,带的风和水平移流从热带海洋获得了全球空气联合海洋空气反应实验(宽外袍 COARE )。结果证明在热带传送对流的开始,发展,和腐烂期间,有水蒸汽的计算过高估计表面雨率,并且遮蔽在在表面雨中在评价上改正的一个重要角色评估的冷凝物戏。分析在热带传送对流的发展期间在深对流的云和铁砧云被执行。在深对流的云和铁砧云与水蒸汽计算的表面雨率有类似的大小,而因为水疗院流星的获得,小表面雨率发生在铁砧云,大表面雨率由于水水疗院流星的消费出现在深对流的云。表面雨评估的格子数据表演的进一步的分析与水蒸汽推测冷凝物主要被贡献,与云,冷凝物否定地与 -0.85, 和与云计算的表面雨率的关联系数被相关在热带深对流的政体的水水疗院流星。 | ZHOU Yushu CUI Xiaopeng LI Xiaofan | 2006 | Progress in Natural Science:Materials International2006，16，9： | 5 |
| 20 | 基于集合卡尔曼滤波的油藏辅助历史拟合显示文摘基于梯度计算的传统优化算法是同时使用观测数据,集合卡尔曼滤波方法是连续使用观测数据,因此它比传统优化算法计算量小.将集合卡尔曼滤波方法作为辅助油藏历史拟合的优化算法,利用序贯高斯模拟生成储层状态的初始实现集合,在算法实现过程中,通过吸收观测数据,实现油藏模型的动态参数(如压力、饱和度)及静态参数(如渗透率)连续更新.通过一个二维的'一注四采'水驱油藏模型的拟合计算,验证算法的有效性,并讨论集合大小和集合采样初始均值对历史拟合结果的影响.在一定范围内,集合样本数对计算精度影响不是很大;对于不同的集合采样初始均值,待估参数能较快地收敛于真值,表明该算法稳定性好. | 张巍 邸元 WU Yushu | 2009 | 大庆石油学院学报2009，33，5： | 4 |
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