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Out-of-plane equilibrium points and invariant manifolds about an asteroid with gravitational orbit–attitude coupling perturbation

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Astrodynamics 2022年第3期6卷 269-283页

作者： Yue Wang ruikang zhang School of Astronautics Beihang UniversityBeijing 102206China

By considering the spacecraft as an extended,rigid body with a prior known attitude instead of a point mass,the attitude-restricted orbital dynamics can improve the precision of the classical point-mass orbital dynamics in close proximity to an asteroid,because it includes the perturbation caused by the gravitational orbit–attitude coupling of the spacecraft(GOACP).The GOACP is defined as the difference between the gravity acting on a non-spherical,extended body(the real case of a spacecraft)and the gravity acting on a point mass(the approximation of a spacecraft in classical orbital dynamics).Inplane equilibrium points that are within the principal planes of the asteroid have been investigated for the attitude-restricted orbital dynamics in previous studies,including equatorial and in-plane non-equatorial equilibrium *** this study,out-of-plane equilibrium points outside the principal planes of the asteroid were ***-ofplane equilibrium points cannot exist in the classical point-mass orbital dynamics but do exist in the attitude-restricted orbital dynamics owing to the effects of the *** previously investigated in-plane equilibrium points and the out-of-plane ones examined in this study provide a complete map of the equilibrium points in close proximity to an asteroid with the *** and in-plane non-equatorial equilibrium points have extended the longitude and latitude ranges of the classical equilibrium points without the GOACP,respectively,while the out-of-plane ones examined in the present study extend both the longitude and latitude ***,the invariant manifolds of out-of-plane equilibrium points were calculated,and the results indicated that the attitude of spacecraft significantly affects the invariant *** practice,these equilibrium points can provide natural hovering positions for operations in proximity to asteroids,and their invariant manifolds can be used for transfers to or from the equilibrium points

关键词： asteroid mission attitude-restricted orbital dynamics gravitational orbit-attitude coupling perturbation(GOACP) out-of-plane equilibrium points invariant manifolds

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Investigation on wavelength switching of widely tunable SGDBR lasers

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Chinese Science Bulletin 2009年第20期54卷 3709-3715页

作者： JIANG Shan DONG Lei zhang ruikang XIE ShiZhong Accelink Technologies Co. Ltd. Wuhan 430074 China School of Information Science and Engineering Shandong University Jinan 250100 China Department of Electronic Engineering Tsinghua University Beijing 100084 China

The sampled-grating distributed Bragg reflector(SGDBR) laser is a typical and important photonic integrated device,and has potential wide application to agile optical networks.A new dynamic model for this device has been developed,which combines the traveling-wave method for the active region and the transfer-matrix method for the passive sections into a single *** behaviors of wave-length switching of the SGDBR laser,which include the transient spectrum and mode competition,have been studied in detail using this model.A new efficient way has been proposed to improve the wavelength switching performance only by increasing the coupling coefficients without changing the carrier density.

关键词：可调谐激光器分布布拉格反射镜光子集成器件动态模型波长交换取样光栅开关性能耦合系数

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Preparation,luminescence and photofunctional performances of a hybrid layered gadolinium-europium hydroxide

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Journal of Rare Earths 2022年第9期40卷 1437-1444,I0004页

作者： Lu Liu Jingjie Yu Shikao Shi Jiye Wang Huihua Song ruikang zhang Lianshe Fu Hebei Key Laboratory of Inorganic Nanomaterials College of Chemistry and Materials ScienceHebei Normal UniversityShijiazhuang 050024China Department of Physics CICECO–Aveiro Institute of MaterialsUniversity of Aveiro3810-193AveiroPortugal

The design and fabrication of rare earth ions incorporated into the inorganic/organic hybrid materials have attracted growing attention for seeking improved optical properties and photofunctional *** this paper,a novel hybrid composite based on the layered rare earth hydroxides was successfully prepared by the ion-exchange and intercalation chemical *** rare earth elements in the composite contain gadolinium(Gd)and europium(Eu)and the molar ratio of Gd to Eu is kept constant at 1.9:*** sodium dodecyl sulfonate and dye coumarin-3-carboxyllc acid are simultaneously incorporated into the layered rare earth hydroxides as supporting agent and light-harvesting antenna,*** resulting hybrid layered rare earth hydroxides exhibit the enlarged interlayer distance with about 2.60 nm,and the chemical composition was confirmed through X-ray diffraction,carbon,hydrogen and nitrogen(CHN)elemental analysis,infrared spectroscopy,and thermogravimetric *** layered solid compound shows the characteristic red emission corresponding to the^(5)D_(0)→^(7)F_(2)transition of Eu^(3+)ion,and the luminescence intensity of the optimized compound is greatly enhanced as compared to its corresponding nitrate and the hybrid composite without the introduction of dye *** hybrid layered rare earth hydroxides can be exfoliated into bright colloidal solution,which show superior recognition capability to Cu^(2+)ion with the distinct luminescence *** large quenching constant(1.4×10^(4)L/mol)and low detection limit(0.35μmol/L)are achieved for Cu^(2+)ion,implying a"turn-off"fluorescent sensor for Cu^(2+)***,a transparent film was prepared based on the colloidal solution and displays the typical red emission in folded *** new hybrid compound with enhanced luminescence and excellent photofunctional performances is expected to be applied in the fields of fluorescent sensing and flexible optical devices.

关键词： Layered rare earth hydroxides Luminescence Eu^(3+)ion Gd^(3+)ion Ion-exchange Intercalation chemistry

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TiO_(2)/CuPc/NiFe-LDH photoanode for efficient photoelectrochemical water splitting

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Chinese Chemical Letters 2021年第3期32卷 1165-1168页

作者： Yanfei Li ruikang zhang Jianming Li Jingchao Liu Yucong Miao Jian Guo Mingfei Shao State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China College of Chemistry and Material Science Hebei Normal UniversityShijiazhuang 050024China Petroleum Geology Research and Laboratory Center Research Institute of Petroleum Exploration&Development(RIPED)PetroChinaBeijing 100083China

Photoelectrochemical(PEC)water splitting is a promising approach for renewable hydrogen ***,the practical PEC solar-to-fuel conversion efficiency is still low owing to poor light absorption and rapid recombination of charge carriers in *** this work,we report a ternary photoanode with simultaneously enhancement of light absorption and water oxidation efficiency by introducing copper phthalocyanine(CuPc)and nickel iron-laye red double hydroxide(NiFe-LDH)on TiO_(2)(denoted as TiO_(2)/CuPc/NiFe-LDH).An experimental study reveals that CuPc loading on TiO_(2)bring strong visible light absorption;NiFe-LDH as an oxygen evolution reaction catalyst efficiently accelerates the surface water oxidation *** synergistic effect of CuPc and NiFe-LDH gives enhanced photocurrent density(2.10 mA/cm^(2)at 0.6 V ***)and excellent stability in the ternary TiO_(2)/CuPc/NiFeLDH photoanode.

关键词： Photoelectrochemical Water splitting TiO_(2)photoanode Layered double hydroxide Photosensitizer

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Influence of reservoir construction on surrounding vegetation cover

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International Journal of Agricultural and Biological Engineering 2021年第3期14卷 214-220页

作者： Ping Liu Xinrui Li ruikang zhang Mengrou Yao Junfeng Chen Yanrong Li Xiangru Jia Yunfei Xing College of Data Science Taiyuan University of TechnologyTaiyuan 030024China College of Water Resources Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China College of Mining Engineering Taiyuan University of TechnologyTaiyuan 030024China

Vegetation is a significant factor in the energy and water *** in vegetation are affected by the natural environment and human *** this study,the Dalong Reservoir on the Ningyuan River in Sanya,Hainan,China,was taken as an example to set one type of buffer zone with the reservoir dam site as the center,and two types of horizontal and vertical buffer zones outwards from both banks of the river,and Landsat 5 remote sensing image data and the vegetation data were applied.A coverage estimation model was used to study the temporal and spatial changes in surface vegetation in three types of buffer zones,and the characteristics of the surface vegetation changes in the preterm,midterm and late-term reservoir construction periods were *** results showed that,(1)During the years 2000 and 2010,the vegetation coverage first decreased and then increased with time in the scope of the *** preterm construction(2000-2004),the vegetation coverage in the upstream region decreased while that in the downstream region *** midterm construction(2004-2006),the declining rate of vegetation coverage downstream was greater than that upstream,but the influence of reservoir construction on vegetation coverage decreased over time in the late-term construction period(2007-2010);(2)Along the direction of the river length,the vegetation coverage showed a downtrend along with the river flow direction during the whole period(2000-2010),and the influence of reservoir construction on vegetation coverage gradually decreased as the distance from the reservoir increased;(3)Along the direction of the river width,the vegetation coverage in the preterm and midterm construction periods(2000-2006)increased with increasing distance from the riverbanks;(4)The vegetation coverage showed a significant increasing trend with increasing distance from the *** research results can provide a theoretical reference for reducing the risk of vegetation degradat

关键词： reservoir remote sensing vegetation coverage ecological environment landscapes

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Macroscale fluorescence imaging against autofluorescence under ambient light

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Light(Science & Applications) 2018年第1期7卷 151-162页

作者： ruikang zhang Raja Chouket Marie-Aude Plamont Zsolt Kelemen Agathe Espagne Alison G.Tebo Arnaud Gautier Lionel Gissot Jean-Denis Faure Ludovic Jullien Vincent Croquette Thomas Le Saux PASTEUR Département de ChimieÉcole Normale SupérieurePSL UniversitySorbonne UniversitéCNRS75005 ParisFrance Institut Jean-Pierre Bourgin INRAAgroParisTechCNRSSaclay Plant Science(SPS)UniversitéParis-SaclayVersaillesFrance Laboratoire de Physique Statistique École Normale SupérieurePSL Research UniversityUniversitéParis Diderot Sorbonne Paris-CitéSorbonne UniversitéCNRS75005 ParisFrance Institut de biologie de l’École normale supérieure(IBENS) École Normale SupérieureCNRSINSERMPSL Research University75005 ParisFrance

Macroscale fluorescence imaging is increasingly used to observe biological ***,it may suffer from spectral interferences that originate from ambient light or autofluorescence of the sample or its *** this manuscript,we built a simple and inexpensive fluorescence macroscope,which has been used to evaluate the performance of Speed OPIOM(Out of Phase Imaging after Optical Modulation),which is a reference-free dynamic contrast protocol,to selectively image reversibly photoswitchable fluorophores as labels against detrimental autofluorescence and ambient *** tuning the intensity and radial frequency of the modulated illumination to the Speed OPIOM resonance and adopting a phase-sensitive detection scheme that ensures noise rejection,we enhanced the sensitivity and the signal-to-noise ratio for fluorescence detection in blot assays by factors of 50 and 10,respectively,over direct fluorescence observation under constant ***,we overcame the strong autofluorescence of growth media that are currently used in microbiology and realized multiplexed fluorescence observation of colonies of spectrally similar fluorescent bacteria with a unique configuration of excitation and emission ***,we easily discriminated fluorescent labels from the autofluorescent and reflective background in labeled leaves,even under the interference of incident light at intensities that are comparable to *** proposed approach is expected to find multiple applications,from biological assays to outdoor observations,in fluorescence macroimaging.

关键词： ambient illumination light

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双小行星探测轨道动力学研究进展

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力学学报 2022年第5期54卷 1155-1185页

作者：王悦伏韬张瑞康北京航空航天大学宇航学院北京102206

双小行星系统由在万有引力作用下彼此环绕的两颗小行星组成,对研究太阳系起源、行星系统演化和行星防御都具有重要的价值,近年来成为行星科学和航天动力学研究的热门对象,对双小行星系统的原位探测也即将迎来热潮.双小行星系统的独特构... 详细信息

双小行星系统由在万有引力作用下彼此环绕的两颗小行星组成,对研究太阳系起源、行星系统演化和行星防御都具有重要的价值,近年来成为行星科学和航天动力学研究的热门对象,对双小行星系统的原位探测也即将迎来热潮.双小行星系统的独特构型和附近的复杂动力学环境为探测器轨道动力学和任务设计带来了全新的挑战,为应对这些挑战所进行的研究也推动了轨道动力学基础理论的发展.本文对双小行星探测轨道动力学的研究进展进行综述,首先介绍了双小行星研究和探测的背景及意义,简要阐述了双小行星系统形成理论及其附近轨道动力学的研究概况.其次,介绍了双小行星系统不规则引力场和相互引力势的建模方法,进而展示了双星的姿态轨道耦合动力学,即完全二体问题,包括双星相对运动的平衡构型和稳定性.接着,介绍了描述双星附近探测器轨道运动的限制性完全三体问题的动力学模型,以及该模型下的平动点、平动点周期轨道、大范围周期轨道、转移轨道和轨道维持等方面的研究进展.第四部分综述了环绕双小行星系统单颗星的受摄二体问题,以轨道摄动理论和行星系统中受摄二体问题的研究现状为背景,介绍了环绕双小行星系统主星的半解析轨道动力学建模与轨道稳定性分析.之后,介绍了目前面向探测任务需求和考虑实际约束的轨道动力学研究和轨道设计.最后,基于目前研究进展,分析了面临的若干问题,对未来双小行星探测轨道动力学及相关技术的发展进行了讨论和展望.

关键词：双小行星系统完全二体问题限制性三体问题受摄二体问题任务轨道设计

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Regrowth-free AlGaInAs MQW polarization controller integrated with a sidewall grating DFB laser

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Photonics Research 2023年第4期11卷 622-630页

作者： XIAO SUN SONG LIANG WEIQING CHENG SHENGWEI YE YIMING SUN YONGGUANG HUANG ruikang zhang JICHUAN XIONG XUEFENG LIU JOHN HMARSH LIANPING HOU James Watt School of Engineering University of GlasgowGlasgow G128QQUK Institute of Semiconductors Chinese Academy of SciencesBeijing 100083China School of Electronic and Optical Engineering Nanjing University of Science and TechnologyNanjing 210094China

Polarization control is at the heart of high-capacity data optical communication systems,such as polarizationdivision multiplexers and Stokes vector modulation *** passive polarization control being mature,the realization of monolithically integrated polarization controllers and single longitudinal mode light sources,such as distributed-feedback(DFB)lasers,is of *** this research,we report an AlGaInAs multiple-quantum-well photonic integrated circuit device which can control the state of polarization of the output light source,consisting of a polarization mode converter(PMC),a differential phase shifter(DPS),and a sidewall grating DFB *** demonstrate an asymmetrical stepped-height ridge waveguide PMC to realize TE to TM polarization conversion and a symmetrical straight waveguide DPS to enable polarization rotation from approximately counterclockwise circular polarization to linear *** on the identical epitaxial layer scheme,all the PMC,DPS,and DFB lasers can be integrated monolithically using only a single step of metalorganic vapor-phase epitaxy and two steps of III-V material dry *** the DFB-PMC device,a high TE to TM polarization conversion efficiency(98.4%)over a wide range of DFB injection currents is reported at 1555 nm *** the DFB-PMC-DPS device,a nearly 60°rotation of the Stokes vector on the Poincarésphere was obtained with a range of bias voltage from 0 to-3.0 V at a laser drive current of 170 mA.

关键词： polarization waveguide rotation

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基于有限元的套管柔性针穿刺软组织弯曲建模研究

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仪器仪表学报 2020年第3期41卷 202-211页

作者：赵燕江房玉康张永德张瑞康哈尔滨理工大学先进制造智能化技术教育部重点实验室哈尔滨150080 哈尔滨理工大学智能机械研究所哈尔滨150080

套管柔性针作为柔性针的一个重要分支,与其他传统的柔性针相比,在针体路径矫正、穿刺灵活性以及斜尖转角控制精度等方面具有巨大的优势。为深入研究套管柔性针穿刺机理,建立基于有限元的穿刺弯曲模型。分析软组织的生物力学特性,建立了... 详细信息

套管柔性针作为柔性针的一个重要分支,与其他传统的柔性针相比,在针体路径矫正、穿刺灵活性以及斜尖转角控制精度等方面具有巨大的优势。为深入研究套管柔性针穿刺机理,建立基于有限元的穿刺弯曲模型。分析软组织的生物力学特性,建立了精确的软组织模型;对套管柔性针穿刺软组织进行受力分析,建立力学模型;在力学模型的基础上,建立套管柔性针穿刺软组织的弯曲模型,进行仿真研究。最后通过实验得到穿刺力-时间曲线和针弯曲变形曲线,并与仿真曲线进行比较。结果表明,仿真结果符合实验穿刺力的变化趋势,系统弯曲误差在2 mm以内,满足医学上的要求,验证了套管柔性针穿刺软组织的力学模型以及弯曲模型的正确性和合理性,为路径规划及控制奠定理论基础。

关键词：套管柔性针软组织建模力学建模弯曲模型有限元分析

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创业利润的源起、扩展及其生产率效应

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政治经济学评论 2023年第4期14卷 197-224页

作者：杨巨张睿康何召鹏湘潭大学商学院中央财经大学经济学院

创业利润是马克思主义经济学家希法亭在《金融资本》中提出的关键概念,经济金融化背景下,研究创业利润有利于解释金融利润的具体来源与深层影响。首先,本文回顾了创业利润的理论源起,在政治经济学框架内对创业利润的实现过程进行了扩展... 详细信息

创业利润是马克思主义经济学家希法亭在《金融资本》中提出的关键概念,经济金融化背景下,研究创业利润有利于解释金融利润的具体来源与深层影响。首先,本文回顾了创业利润的理论源起,在政治经济学框架内对创业利润的实现过程进行了扩展分析,将创业利润划分为留存创业利润和让渡创业利润,阐述了创业利润分配对上市企业生产率的影响。然后,本文以我国A股上市公司为样本,计算了留存创业利润和让渡创业利润,发现让渡创业利润在过去较长时间里脱离留存创业利润,成为我国经济金融化的重要推手;基于基准回归、工具变量和政策冲击方法,发现让渡创业利润占比(留存创业利润占比)对企业生产率存在显著负面(正面)影响。因此,优化企业上市定价与发行制度,确保创业利润更多地流入上市企业,可以更好地发挥创业利润的积极作用,进而提高上市公司质量;同时,完善机构投资相关法律制度,通过机构投资分享留存创业利润再投资所带来的长期收益,可以增加城乡居民财产性收入,发挥股票市场在促进共同富裕中的重要作用。

关键词：创业利润金融利润经济金融化让渡创业利润留存创业利润

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