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Modified super twisting controller for servicing to uncontrolled spacecraft

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Journal of Systems Engineering and Electronics 2015年第2期26卷 334-345页

作者： binglong chen Yunhai Geng Research Center of Satellite Technology Harbin Institute of Technology

A relative position and attitude coupled sliding mode controller is proposed by combining the standard super twisting （ST） control and basic linear algorithm for autonomous rendezvous and docking. It is schemed for on-orbit servicing to a tumbling non- cooperative target spacecraft subjected to external disturbances. A coupled dynamic model is established including both kinemati- cal and dynamic coupled effect of relative rotation on relative translation, which illustrates the relative movement between the docking port located in target spacecraft and another in service spacecraft. The modified super twisting （MST） control algorithm containing linear compensation items is schemed to manipulate the relative position and attitude synchronously. The correction provides more robustness and convergence velocity for dealing with linearly growing perturbations than the ST control algorithm. Moreover, the stability characteristic of closed-loop system is ana- lyzed by Lyapunov method. Numerical simulations are adopted to verify the analysis with the comparison between MST and ST control algorithms. Simulation results demonstrate that the pro- posed MST controller is characterized by high precision, strong robustness and fast convergence velocity to attenuate the linearly increasing perturbations.

关键词： autonomous rendezvous and docking coupled dynamic model modified super twisting Lyapunov method

Smoothing positive currents and the existence of Khler-Einstein metrics

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Science China Mathematics 2012年第5期55卷 893-912页

作者： chen binglong Department of Mathematics Sun Yat-Sen UniversityGuangzhou 510275China

In this paper,we prove a general existence theorem of Khler-Einstein metrics on complete Khler *** use the heat equation method smoothing certain positive (1,1) current in the canonical class.

关键词： Khler-Einstein metric

YAU'S UNIFORMIZATION CONJECTURE FOR MANIFOLDS WITH NON-MAXIMAL VOLUME GROWTH

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Acta Mathematica Scientia 2018年第5期38卷 1468-1484页

作者： binglong chen Xiping ZHU Department of Mathematics Sun Yat-sen UniversityGuangzhou 510275China

The well-known Yau＇s uniformization conjecture states that any complete noncompact Kahler manifold with positive bisectional curvature is bi-holomorphic to the Euclidean space. The conjecture for the case of maximal volume growth has been recently confirmed, by G. Liu in [23]. In the first part, we will give a survey on thc progress. In the second part, we will consider Yau＇s conjecture for manifolds with non-maximal volume growth. We will show that the finiteness of the first Chern number Cn1 is an essential condition to solve Yau＇s conjecture by using algebraic embedding method. Moreover, we prove that, under bounded curvature conditions, Cn1 is automatically finite provided that there exists a positive line bundle with finite Chern number. In particular, we obtain a partial answer to Yau＇s uniformization conjecture on Kahler manifolds with minimal volume growth.

关键词： uniformization conjecture non-maximal volume growth Chern number

Canonical solitons associated with generalized Ricci flows

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Science China Mathematics 2013年第10期56卷 2007-2013页

作者： chen binglong GU HuiLing Department of Mathematics Sun Yat-sen University

We construct the canonical solitons,in terms of Cabezas-Rivas and Topping,associated with some generalized Ricci flows.

关键词： canonical soliton generalized Ricci flow harmonic map heat flow differential form heat flow

Atmospheric temperature dependence of the aerosol backscattering coefficient

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Particuology 2016年第5期14卷 72-76页

作者： binglong chen Siying chen Yinchao Zhang He chen Pan Guo Hao chen Key Laboratory of Photoelectronic Imaging Technology Beijing Institute of Technology Beijing 100081 China

In extracting vertical profiles of aerosol backscattering coefficient from lidar signals, the effects of atmo- spheric temperature are usually ignored, In this study, these effects are analyzed using a rotational Raman-Mie lidar system, which is capable of simultaneously measuring atmospheric temperature and vertical profiles of aerosols, A method is presented to correct the aerosol backscattering coefficient using atmospheric temperature profiles, obtained from Raman scattering signals. The differences in the extracted aerosol backscattering coefficient with and without considering temperature effects are fur- ther discussed. The backscattering coefficients for scattering off clouds are shown to be more sensitive to temperature than that of aerosols and atmosphere molecules; the aerosol backscattering coefficient is more sensitive to temperature in summer due to higher atmospheric temperatures,

关键词： Lidar Atmospheric temperature Aerosol Raman scattering Backscattering coefficient

A Precise and Robust Control Strategy for Rigid Spacecraft Eigenaxis Rotation

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Chinese Journal of Aeronautics 2011年第4期24卷 484-492页

作者： CONG binglong LIU Xiangdong chen Zhen School of Automation Beijing Institute of Technology Beijing 100081 China

Eigenaxis rotation is generally regarded as a near-minimum time strategy for rapid attitude maneuver due to its constitution of the shortest angular path between two orientations. In this paper, the robust control problem of rigid spacecraft eigenaxis rotation is investigated via time-varying sliding mode control （TVSMC） technique. Both external disturbance and parameter variation are taken into account. Major features of this robust eigenaxis rotation strategy are first demonstrated by a TVSMC algorithm. Global sliding phase is proved as well as the closed-loop system stability. Additionally, the necessary condition for eigenaxis rotation is provided. Subsequently, to suppress the global chattering and improve the control accuracy, a disturbance observer-based time-varying sliding mode control （DOTVSMC） algorithm is presented, where the boundary layer approach is used to soften the chattering and a disturbance observer is designed to attenuate undesired effect. The spacecraft attitude is represented by modified Rodrigues parameter （MRP） for the non-redundancy. Finally, a numerical simulation is employed to illustrate the effectiveness of the proposed strategy, where the pulse-width pulse-frequency （PWPF） technique is utilized to modulate the on-off thrusters.

关键词： attitude control eigenaxis maneuver time-varying sliding mode control global robust disturbance observer pulse-width pulse-frequency modulator

对失控航天器在轨服务的自适应滑模控制器设计

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航空学报 2015年第5期36卷 1639-1649页

作者：陈炳龙耿云海哈尔滨工业大学卫星技术研究所哈尔滨150080

为实现对自由翻滚的失控目标航天器进行在轨服务,基于二阶滑模控制算法设计了相对位置与姿态耦合的自适应控制器。考虑相对转动对相对平动的耦合作用,建立了两航天器对接端口间相对位置与姿态耦合的动力学模型,并在此基础上设计了自适应... 详细信息

为实现对自由翻滚的失控目标航天器进行在轨服务,基于二阶滑模控制算法设计了相对位置与姿态耦合的自适应控制器。考虑相对转动对相对平动的耦合作用,建立了两航天器对接端口间相对位置与姿态耦合的动力学模型,并在此基础上设计了自适应Super twisting控制器,以减弱已知界限的有界干扰所产生的震颤效应,使闭环系统在有限时间内收敛到平衡点。利用李雅普诺夫方法证明了有界干扰下的闭环系统稳定性,并对收敛时间的上界进行了估计。仿真结果表明,与Super twisting算法相比,所设计的自适应二阶滑模控制器对参数不确定性及线性增长有界干扰具有较强的鲁棒性,且控制精度满足在轨服务的任务需求。

关键词：航天器在轨服务滑模控制自适应控制相对平动相对转动有限时间收敛鲁棒性

发酵条件和青贮时间对黑麦草色素和植物醇含量的影响

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中国饲料 2020年第10期 25-28页

作者：陈秉龙青海省海北州草原工作站青海海北810299

本研究旨在探讨青贮时间及青贮时添加乳酸菌对黑麦草化学成分、色素及植物醇含量的影响。试验1:将用塑料袋包装的黑麦草进行为期5周的青贮,测定化学成分及色素含量变化。试验2:将不添加任何添加剂青贮的黑麦草作为对照组,处理组在青贮... 详细信息

本研究旨在探讨青贮时间及青贮时添加乳酸菌对黑麦草化学成分、色素及植物醇含量的影响。试验1:将用塑料袋包装的黑麦草进行为期5周的青贮,测定化学成分及色素含量变化。试验2:将不添加任何添加剂青贮的黑麦草作为对照组,处理组在青贮过程添加乳酸菌,两组黑麦草共青贮60d。结果 :青贮第5周时,黑麦草的pH最低(P <0.05),乳酸、乙酸和丁酸含量最高(P <0.05)。黑麦草在青贮第5周粗蛋白质含量显著提高(P <0.05),而粗脂肪含量在青贮0~2周时随青贮时间的延长显著升高(P <0.05)。黑麦草青贮前,叶绿素a、叶绿素b及叶绿素a+b含量最高,之后随着青贮时间的延长显著降低(P <0.05),但脱镁叶绿素a在青贮前最低,之后随青贮时间的延长显著升高(P <0.05)。乳酸菌组pH较对照组显著降低31.52%(P <0.05),乳酸含量较对照组显著提高438.89%(P <0.05)。青贮后(加或不加乳酸菌)较青贮前粗脂肪含量显著提高46.04%和40.59%(P <0.05),中性洗涤纤维含量显著降低6.42%和5.17%(P <0.05)。黑麦草青贮后的叶绿素a、叶绿素a+b和β-胡萝卜素含量显著降低(P <0.05)。结论 :乳酸菌发酵黑麦草降低了pH,提高了β-胡萝卜素含量。无论何种发酵条件,青贮黑麦草中的叶黄素和叶绿醇含量均保持较好。

关键词：黑麦草发酵色素化学成分

塔里木板块东北缘坡北杂岩体矿物成分和铂族元素特征:对硫化物熔离和构造环境的约束

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岩石学报 2018年第8期34卷 2223-2244页

作者：王梦玺陈炳龙焦建刚长安大学地球科学与资源学院西安710064 国土资源部岩浆作用成矿与找矿重点实验室西安710064 教育部西部矿产资源与地质工程重点实验室西安710064

坡北杂岩体位于塔里木板块东北缘北山裂谷带,主要由橄榄岩相、单辉辉石岩相、二辉岩相、辉长岩相、苏长岩相和辉长苏长岩相组成。坡一岩体中硫化物矿体赋存于超镁铁质岩中,而坡东岩体中硫化物矿体赋存于辉长苏长岩相中。坡一和坡东岩体... 详细信息

坡北杂岩体位于塔里木板块东北缘北山裂谷带,主要由橄榄岩相、单辉辉石岩相、二辉岩相、辉长岩相、苏长岩相和辉长苏长岩相组成。坡一岩体中硫化物矿体赋存于超镁铁质岩中,而坡东岩体中硫化物矿体赋存于辉长苏长岩相中。坡一和坡东岩体不同岩相中单斜辉石的MgO和CaO含量、斜长石的An值和SiO_2含量连续变化且呈负相关,说明二者可能是同一原始岩浆分离结晶的产物。根据前人计算的原始岩浆成分,我们利用MELTS软件模拟了坡北杂岩体的分离结晶过程。结果表明矿物结晶顺序为:橄榄石→橄榄石+单斜辉石→橄榄石+单斜辉石+斜长石→单斜辉石+斜长石+斜方辉石,与岩相观察一致。坡北杂岩体原始岩浆经过20%分离结晶达到S饱和而发生早期硫化物熔离,形成坡一岩体中矿体。因此,在利用具有最高Fo值(90.9mol%)的橄榄石成分进行的模拟中,坡一岩体早期结晶的纯橄榄岩中橄榄石成分与分离结晶趋势线一致,而斜长橄榄岩中橄榄石成分低于趋势线,可能形成于早期硫化物熔离之后。随后岩浆中S再一次不饱和,但坡一岩体橄榄单辉辉石岩和辉长岩中橄榄石Fo和Ni含量在分离结晶趋势线之下,同时坡东岩体不含矿岩石中铂族元素总量主要在8.9×10^(-9)～29.0×10^(-9)之间,且相对于Ni和Cu明显亏损,说明在岩浆分离结晶晚期再次发生硫化物熔离,而且可能是地壳混染引起的,并形成了坡东岩体中的硫化物矿体。坡东岩体橄榄二辉岩和橄榄辉长苏长岩中橄榄石Fo值(74.5mol%～81.0mol%)较低,但变化范围较大,且Fo和Ni呈负相关关系,这可能是由于橄榄石和硫化物熔体在不平衡状态下发生成分交换造成的。坡北杂岩体超镁铁质岩石中单斜辉石Ti O2含量为0.21%～0.83%,阳离子中呈四次配位的Al(AlZ)为0.8mol%～7.8mol%,与裂谷环境堆晶岩中单斜辉石成分相似。因此,坡北杂岩体可能形成于和塔里木二叠纪地幔柱活动相关的裂谷环境。然而,超镁铁质岩石全岩Nd同位素指示其来源于亏损地幔,并不是地幔柱物质熔融的直接产物。纯橄榄岩和异剥橄榄岩La/Sm,Sm/Yb和La/Yb比值指示其源区为尖晶石二辉橄榄岩地幔。因此,坡北杂岩体源区应为浅部以尖晶石二辉橄榄岩为主的亏损岩石圈地幔,地幔柱在源区部分熔融过程中提供了大量的热。

关键词：矿物成分铂族元素(PGE) 硫化物熔离坡北杂岩体大地构造环境