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Disturbance Observer-based Pointing Control of Leighton Chajnantor Telescope

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Research in Astronomy and Astrophysics 2024年第1期24卷 135-150页

作者： Weirui Chen zheng Wang School of Automation Southeast UniversityNanjing 210096China Key Laboratory of Measurement and Control of Complex Systems of Engineering Ministry of EducationSoutheast UniversityNanjing 210096China

Leighton Chajnantor Telescope(LCT), i.e., the former Caltech Submillimeter Observatory telescope, will be refurbished at the new site in Chajnantor Plateau, Chile in 2023. The environment of LCT will change significantly after its relocation, and the telescope will be exposed to large wind disturbances directly because its enclosure will be completely open during observation. The wind disturbance is expected to be a challenge for LCT's pointing control since the existing control method cannot reject this disturbance very well. Therefore, it is very necessary to develop a new pointing control method with good capability of disturbance rejection. In this research, a disturbance observer—based composite position controller(DOB-CPC) is designed, in which an h∞feedback controller is employed to compress the disturbance, and a feedforward linear quadratic regulator is employed to compensate the disturbance precisely based on the estimated disturbance signal. Moreover, a controller switching policy is adopted, which applies the proportional controller to the transient process to achieve a quick response and applies the DOB-CPC to the steady state to achieve a small position error. Numerical experiments are conducted to verify the good performance of the proposed pointing controller(i.e., DOB-CPC) for rejecting the disturbance acting on LCT.

关键词： instrumentation:miscellaneous methods:analytical methods:numerical telescopes

Towards combining multiple geophysical datasets to determine earthquake source parameters in China

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Science China Earth Sciences 2016年第11期59卷 2260-2262页

作者： zheng Yong LIU ChengLi State Key Laboratory of Geodesy and Earth's Dynamics Institute of Geodesy and Geophysics Chinese Academy of Sciences

*** of conventional seismic studies on earthquake source parameters Earthquake source parameters,including magnitude,location,focal mechanism,rupture process are key factors for understanding seismogenic environment,mitigating seismic hazards,estimating earthquake triggering,and tectonic ***,source parameters are determined by seismological *** example,Fang L h et al.（2014）relocated the 2012 Ms6.6 Xinjiang Xinyuan earthquake sequence using local seismograms based on the double difference method,

关键词： geophysical tectonic rupture triggering magnitude estimating moderate epicenter constrain spatially

Factors influencing peak bone mass gain

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Frontiers of Medicine 2021年第1期15卷 53-69页

作者： Xiaowei Zhu houfeng zheng Disease&Population(DaP)Geninfo Lab School of Life SciencesWestlake UniversityHangzhou 310024China Institute of Basic Medical Sciences Westlake Institute for Advanced StudyWestlake UniversityHangzhou 310024China School of Life Sciences Fudan UniversityShanghai 200433China

Bone mass is a key determinant of osteoporosis and fragility *** studies have shown that a 10%increase in peak bone mass(PBM)at the population level reduces the risk of fracture later in life by 50%.Low PBM is possibly due to the bone loss caused by various conditions or processes that occur during adolescence and young ***,gender,and family history(genetics)are responsible for the majority of PBM,but other factors,such as physical activity,calcium and vitamin D intake,weight,smoking and alcohol consumption,socioeconomic status,age at menarche,and other secondary causes(diseases and medications),play important roles in PBM gain during childhood and ***,the optimization of lifestyle factors that affect PBM and bone strength is an important strategy to maximize PBM among adolescents and young people,and thus to reduce the low bone mass or osteoporosis risk in later *** review aims to summarize the available evidence for the common but important factors that influence bone mass gain during growth and development and discuss the advances of developing high PBM.

关键词： peak bone mass children adolescents genetic risk factors

GRAIN　BOUNDARY　SEGREGATION　AND　INTERGRANULAR　BRITTLENESS　IN　hIGh　STRENGTh　ALUMINIUM　ALLOY

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中国有色金属学会会刊：英文版 1995年第3期5卷 97-100页

作者： Song, Renguo zheng, Meiguang Northeastern Univ Shenyang China

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关键词： high strength aluminium alloy grain boundary segregation intergranular brittleness

Structure Prediction Based on hydrophobic to hydrophilic Volume Ratios in Small Molecule Amphiphilic Organic Crystals

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Chinese journal of Structural Chemistry 2002年第6期21卷 592-596页

作者： zheng－TaoXu StephenLee DepartmentofChemistryandChemicalBiology BakerLaboratoryCornellUniversityIthacaNY14853－1301 Authortowhomcorrespondenceshouldbeaddressed

The structure type for the crystal of 4,4'-bis-(2-hydroxy-ethoxyl)-biphenyl 1 has been predicted by using the previously developed interfacial model for small organic molecules. Based on the calculated hydrophobic to hydrophilic volume of 1, this model predicts the crystal structure to be of lamellar or bicontinuous type, which has been confirmed by the X-ray single-crystal structure analysis (C20h26O6, monoclinic, P21/C, a = 16.084(1), b = 6.0103(4), c = 9.6410(7) A, β9 = 103.014(2)°, V= 908.1(1) A3, Z = 2, Dc= 1.325 g/cm3, F(000)=388,μ = 0.097 mm-1, MoKα radiation, λ = 0.71073 A, R = 0.0382 and wR = 0.0882 with I > 2σ(I) for 7121 reflections collected, 1852 unique reflections and 170 parameters). As predicted, the hydrophobic and hydrophilic portions of 1 form in the lamellae. The same interfacial model is applied to other amphilphilic small molecule organic systems for structural type prediction.

关键词： amphiphilic system minimal surface organic crystal structure prediction

Categorical computation

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Frontiers of physics 2023年第2期18卷 181-187页

作者： Liang Kong hao zheng Shenzhen Institute for Quantum Science and Engineering Southern University of Science and TechnologyShenzhen 518055China International Quantum Academy Shenzhen 518048China Guangdong Provincial Key Laboratory of Quantum Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Institute for Applied Mathematics Tsinghua UniversityBeijing 100084China Beijing Institute of Mathematical Sciences and Applications Beijing 101408China Department of Mathematics Peking UniversityBeijing 100871China

In quantum computing, the computation is achieved by linear operators in or between hilbert spaces. In this work, we explore a new computation scheme, in which the linear operators in quantum computing are replaced by (higher) functors between two (higher) categories. If from Turing computing to quantum computing is the first quantization of computation, then this new scheme can be viewed as the second quantization of computation. The fundamental problem in realizing this idea is how to realize a (higher) functor physically. We provide a theoretical idea of realizing (higher) functors physically based on the physics of topological orders.

关键词： quantum computation categorical computation topological order

homotopy analysis solutions for the asymmetric laminar flow in a porous channel with expanding or contracting walls

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Acta Mechanica Sinica 2011年第2期27卷 208-214页

作者： X.-h. Si L.-C. zheng X.-X. Zhang Y. Chao Applied Science School University of Science and Technology Beijing 100083 Beijing China Department of Mechanical Engineering University of Science and Technology Beijing100083 Beijing China Research Institute of Chemical Defense of the EL.A 102205 Beijing China

In this paper, the asymmetric laminar flow in a porous channel with expanding or contracting walls is investigated. The governing equations are reduced to ordinary ones by using suitable similar transformations. homotopy analysis method （hAM） is employed to obtain the expres- sions for velocity fields. Graphs are sketched for values of parameters and associated dynamic characteristics, especially the expansion ratio, are analyzed in detail.

关键词： homotopy analysis method · Expanding or contracting wall · Asymmetric laminar flow · Porous channel · Expansion ratio

Prediction of dispersed phase holdup in pulsed disc and doughnut solvent extraction columns under different mass transfer conditions

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Chinese journal of Chemical Engineering 2016年第2期24卷 226-231页

作者： Yong Wang Kathryn h.Smith Kathryn Mumford Teobaldo F.Grabin zheng Li Geoffrey W.Stevens Particulate Fluids Processing Centre Department of Chemical and Biomolecular EngineeringThe University of Melbourne

Using experimental data from a number of pulsed disc and doughnut solvent extraction columns, a unified correla- tion for the prediction of dispersed phase holdup that considers the effects of mass transfer is presented. Pulsed disc and doughnut solvent extraction columns （PDDC） have been used for a range of important applications such as ura- nium extraction and nuclear fuel recycling. Although the dispersed phase holdup in a PDDC has been presented by some researchers, there is still the need to develop a robust correlation that can predict the experimental dispersed phase holdup over a range of operating conditions including the effects of mass transfer direction. In this study, dis- persed phase holdup data from different literature sources for a PDDC were used to refit constants for the correlation presented by Kumar and hartland lind. Eng. Chem. Res.,27 （1988）,131-138] which did not consider the effect of col- umn geometry. In order to incorporate the characteristic length of the PDDC （i.e. the plate spacing）, the unified cor- relation for holdup proposed by Kumar and hartland based on data from eight different types of columns [Ind. Eng. Chem. Res.,34 （1995） 3925-3940] was refitted to the PDDC data. New constants have been presented for each hold- up correlation for a PDDC based on regression analysis using published holdup data from PDDCs that cover a range of onerating conditions and nhwical nronerties and consider the direction of mass transfer.

关键词： Solvent extraction Liquid extraction Pulsed disc and doughnut columns Solvent extraction column design holdup Dispersed phase holdup hydrodynamics of extraction columns

Inorganic Nanotube/Organic Nanoparticle hybrids for Enhanced Photoelectrochemical Properties

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journal of Materials Science & Technology 2017年第7期33卷 728-733页

作者： Yingzhi Chen Aoxiang Li Ming jin Lu-Ning Wang zheng-hong huang Key Laboratory of Advanced Materials （MOE） School of Materials Science and Engineering Tsinghua University Beijing 100084 China

Inorganic/organic nanohybrids composed of arrayed TiO_2 nanotubes（Ti NTs）/porphyrin nanoparticles（NPs） have been fabricated via a wet chemical approach. The inorganic component, particularly the arrayed one-dimensional（1D） nanostructures, provides high charge-carrier mobility and rapid charge transport. The organic component exhibits extensive visible light absorption and good solution processability. Additionally, the geometric restraint by supramolecular assembly renders an improved photostability. A combination of these two components could thus allow for an efficient solar energy conversion. In this work, a colloid of porphyrin NPs prepared by a solvent exchange method is coated on anodic Ti NTs by means of a dip-coating treatment to form inorganic/organic hybrids. The hybrids exhibit an improvement on solar absorption and a significant enhancement on photocurrent generation at a small bias compared with individual component. herein, the inorganic/organic nanohybrids are proved to be excellent photoanodes highly responsive to visible light and thus pave a way to discover new inorganic/organic assemblies for high-performance optoelectronic applications, as well as for device integration.

关键词： Anodic TiO_2 nanotubes Porphyrin nanoparticles Inorganic/organic nanohybrid Photoelectrochemical water splitting