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Evolution of Galaxy Types and HI Gas in Hickson Compact Groups

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Research in Astronomy and Astrophysics 2022年第10期22卷 189-201页

作者： Yao Liu ming zhu National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China CAS Key Laboratory of FAST NAOCChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

Compact groups have high galaxy densities and low velocity dispersions,and their group members have experienced numerous and frequent interactions during their *** provide a unique environment to study the evolution of *** examined the galaxies types and H I contents in groups to make a study on the galaxy evolution in compact *** used the group crossing time as an age indicator for galaxy *** sample is derived from the Hickson Compact Group *** obtained group morphology data from the Hyper-Leda database and the IR classification based on Wide-Field Infrared Survey Explorer fluxes from Zucker et *** cross-matching the latest released ALFALFA 100%H I source catalog with supplement by data found in literature,we obtained 40 galaxy groups with H I data *** confirmed that the weak correlation between H I mass fraction and group crossing time found by Ai&zhu in SDSS groups also exists in compact *** also found that the group spiral galaxy fraction is correlated with the group crossing time,but the actively star-forming galaxy fraction is not correlated with the group crossing *** results seem to fit with the hypothesis that the sequential acquisition of neighbors from surrounding larger-scale structures has affected the morphology transition and star formation efficiency in compact groups.

关键词： galaxies evolution-galaxies groups general-galaxies ISM

Multi-transition study of the peculiar merger Arp 299

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Research in Astronomy and Astrophysics 2017年第8期17卷 1-12页

作者： Qian Jiao ming zhu National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Key Laboratory of Radio Astronomy Chinese Academy of Sciences Beijing 100012 China University of Chinese Academy of Sciences Beijing 100049 China

We present a multi-transition study to investigate the physical properties of dust and molecular gas in the archetypical merger Arp 299 by using data including James Clerk Maxwell Telescope(JCMT)850 and 450 μm observations, Herschel 500, 350, 250, 160 and 70 μm continuum maps, as well as the CO(3–2), CO(4–3) low-J CO lines and CO(11–10), CO(13–12), CO(14–13) high-J CO lines. The CO(3–2) and CO(4–3) lines are observed by JCMT, and the CO(11–10), CO(13–12), CO(14–13) lines are available on the Herschel Science Archive. The resolution of the Herschel Spectral and Photometric Imaging Receiver(SPIRE) Fourier transform spectrometer(FTS) CO(11–10) data is similar to that of the JCMT CO(3–2) line, while the resolution of the SPIRE/FTS CO(13–12) and Photodetector Array Camera and Spectrometer(PACS) CO(14–13) data is similar to that of JCMT CO(4–3), allowing us to obtain accurate line ratios of I(CO(11-10))/I(CO(3-2)), I(CO(13-12))/I(CO(4-3))and I(CO(14-13))/I(CO(4-3)).By modeling the spectral energy distribution of the continuum data, we conclude that two components(cold and warm) exist in the dust, with the warm component occupying a small percent of the total dust mass. We further use a radiative transfer analysis code, RADEX, to calculate the density, temperature and column density of warm gas in the central region, which shows that the kinetic temperature Tkinis in the range 110 to 150 K and hydrogen density n(H2) is in the range 104.7-105.5cm-3. We show that the hot dust is located in the central region of IC 694 with a radius of ~ 4′′and estimate that the warm gas mass is in the range 3.8 × 10~7M⊙to 7.7 × 10~7M⊙, which contains 5.0%–15.0% of the total H2mass for the region of IC 694. We also calculate the star formation rate of the galaxy in particular,which is much higher than that of the Milky Way.

关键词： galaxies merge — galaxies Arp 299 — galaxies dust — galaxies molecular gas — galaxies warm center

Improved patch antenna performance by using a metamaterial cover

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第2期8卷 192-196页

作者： zhu Fang-ming HU Jun Department of Electrical Engineering Hangzhou Teachers College Hangzhou 310036 China Center for Optical and Electromagnettc Research Zhejiang University Hangzhou 310027 China

A new patch antenna system with a metamaterial cover is presented in this paper. The impedance, radiation pattem, and directivity of such an antenna are studied. A performance comparison between the conventional patch antenna and the new metamaterial patch antenna is given. The results show that the directivity of the metamaterial patch antenna is significantly improved. The effect of the metamaterial cover＇s layer numbers on the radiation pattern of the patch antenna is also studied.

关键词： Directivity Metamaterial Patch antenna

Mechanism of Bainite Nucleation in Steel, Iron and Copper Alloys

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Journal of Materials Science & Technology 2005年第4期21卷 437-444页

作者： Mokuang KANG ming zhu mingxing ZHANG School of Materials Science and Engineering Northwestern Polytechnical University Xi'an 710072 China School of Engineering University of Quensland Brisbane Qld 4072 Australia

During the incubation period of isothermal treatment（or aging） within the bainitic transformation temperature range in a salt bath （or quenching in water） immediately after solution treatment, not only are the defects formed at high temperatures maintained, but new defects can also be generated in alloys, iron alloys and steels. Due to the segregation of the solute atoms near defects through diffusion, this leads to non-uniform distributions of solute atoms in the parent phase with distinct regions of both solute enrichment and solute depletion. It is proposed that when the Ms temperature at the solute depleted regions is equal to or higher than the isothermal （or aged） temperature,nucleation of bainite occurs within these solute depleted regions in the manner of martensitic shear. Therefore it is considered that, at least in steel, iron and copper alloy systems, bainite is formed through a shear mechanism within solute depleted regions, which is controlled and formed by the solute atoms diffusion in the parent phase.

关键词： Pre-bainite phenomenon Solute segregation Solute depleted region Martensitic shear Spinodal-like decomposition (Modulated structure)

Multi-disciplinary design optimization with variable complexity modeling for a stratosphere airship

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Chinese Journal of Aeronautics 2019年第5期32卷 1244-1255页

作者： Shi YIN ming zhu Haoquan LIANG School of Aeronautic Science and Engineering Beihang University School of Automation Science and Electrical Engineering Beihang University

This paper proposes a hybrid architecture based on Multi-disciplinary Design Optimization(MDO) with the Variable Complexity Modeling(VCM) method, to solve the problem of general design optimization for a stratosphere airship. Firstly, MDO based on the Concurrent SubSpace Optimization(CSSO) strategy is improved for handling the subsystem coupling problem in stratosphere airship design which contains aerodynamics, structure, and energy. Secondly, the VCM method based on the surrogate model is presented for reducing the computational complexity in high-fidelity modeling without loss of accuracy. Moreover, the global-to-local optimization strategy is added to the architecture to enhance the process. Finally, the result gives a prominent stratosphere airship general solution that validates the feasibility and efficiency of the optimization architecture. Besides, a sensitivity analysis is conducted to outline the critical impact upon stratosphere airship design.

关键词： Multi-disciplinary design optimization Sensitivity analysis Stratosphere airship Surrogate model Variable complexity modeling

Homoclinic and Periodic Orbits Arising Near the Heteroclinic Cycle Connecting Saddle-focus and Saddle Under Reversible Condition

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Acta Mathematica Sinica,English Series 2007年第8期23卷 1495-1504页

作者： De ming zhu Ying SUN Department of Mathematics East China Normal University Shanghai 200062 P. R. China School of Science University of Ji'nan Ji'nan 250022 P. R. China

In this paper, we study the dynamical behavior for a 4-dimensional reversible system near its heteroclinic loop connecting a saddle-focus and a saddle. The existence of infinitely many reversible 1-homoclinic orbits to the saddle and 2-homoclinic orbits to the saddle-focus is shown. And it is also proved that, corresponding to each 1-homoclinic （resp. 2-homoclinic） orbit F, there is a spiral segment such that the associated orbits starting from the segment are all reversible 1-periodic （resp. 2-periodic） and accumulate onto F. Moreover, each 2-homoclinic orbit may be also accumulated by a sequence of reversible 4-homoclinic orbits.

关键词： reversible condition homoclinic orbit Poincare map periodic orbit saddle-focus

An optimized sequential extraction scheme for molybdenum association in environmental samples

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Acta Geochimica 2016年第2期35卷 111-119页

作者： Liang Liang Jian-ming zhu State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of SciencesGuiyang 550081 People's Republic of China State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Beijing 100083China University of Chinese Academy of Sciences Beijing 100049People's Republic of China

By comparing three sequential extraction pro- cedures, a new optimized extraction scheme for the molyb- denum association in environmental samples was proposed. Five operational steps were described as exchangeable （KH2PO4 ＋ K2HPO4： including water-soluble）, associated with organic matter （NaOH）, Fe-Mn oxides and/or carbonates （HC1）, sulfides （H2O2） and residue （HNO3 ＋ HF ＋ H2O2）. An optimized extraction scheme was com- pared with Tessier＇s procedure and the Commission of European Communities Bureau of Reference （BCR） was applied to black shales. Results showed Tessier＇s procedure gave the lowest concentration values for exchangeable molybdenum and the highest values for the residual molybdenum, which could not present the efficiency of the extraction reagents. BCR＇s procedure showed the highest values in oxidizable molybdenum and presented four fractions of molybdenum, which did not demonstrate the fractions of molybdenum in the black shales in detail. The optimized extraction scheme demonstrated a certain improvement on extraction efficiency over Tessier＇s proce- dure for the lowest residual molybdenum, and revealed morefeatured fraction information of molybdenum in black shales than BCR＇ s. Therefore, after a comparison with other two extraction procedures, the optimized extraction scheme proved suitable for the molybdenum in black shales and it also showed an accurate determination of the molybdenum in the fractions and source of bioavailable Mo.

关键词： Molybdenum Sequential extractionprocedure Black shales

An Adaptive Single Neural Control for Variable Step-Size P&O MPPT of Marine Current Turbine System

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China Ocean Engineering 2021年第5期35卷 750-758页

作者： LI ming-zhu WANG Tian-zhen ZHOU Fu-na SHI ming Logistics Engineering College Shanghai Maritime UniversityShanghai 201306China Shanghai Investigation Design and Research Institute Co.LtdShanghai 200434China

Marine current energy has been increasingly used because of its predictable higher power *** to the external disturbances of various flow velocity and the high nonlinear effects on the marine current turbine(MCT)system,the nonlinear controllers which rely on precise mathematical models show poor performance under a high level of parameters’*** paper proposes an adaptive single neural control(ASNC)strategy for variable step-size perturb and observe(P&O)maximum power point tracking(MPPT)***,to automatically update the neuron weights of SNC for the nonlinear systems,an adaptive mechanism is proposed to adaptively adjust the weighting and learning ***,aiming to generate the exact reference speed for ASNC to extract the maximum power,a variable step-size law based on speed increment is designed to strike a balance between tracking speed and accuracy of P&O *** robust stability of the MCT control system is guaranteed by the Lyapunov *** simulation results show that this strategy has favorable adaptive performance under variable velocity conditions,and the MCT system operates at maximum power point steadily.

关键词： marine current turbine system perturb and observe single neural control adaptive mechanism maximum power point tracking

Integrated HI emission in galaxy groups and clusters

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Research in Astronomy and Astrophysics 2017年第10期17卷 15-26页

作者： Mei Ai ming zhu Jian Fu National Astronomical Observatories Chinese Academy of Sciences Key Laboratory of Radio Astronomy Chinese Academy of Sciences University of Chinese Academy of Sciences Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical Observatory Chinese Academy of Sciences

The integrated HI emission from hierarchical structures such as groups and clusters of galax- ies can be detected by FAST at intermediate redshifts. Here we propose to use FAST to study the evolution of the global HI content of clusters and groups over cosmic time by measuring their integrated HI emissions. We use the Virgo Cluster as an example to estimate the detection limit of FAST, and have estimated the integration time to detect a Virgo type cluster at different redshifts （from z = 0.1 to z ---- 1.5）. We have also employed a semi-analytic model （SAM） to simulate the evolution of HI contents in galaxy clusters. Our simulations suggest that the HI mass of a Virgo-like cluster could be 2-3 times higher and the physical size could be more than 50% smaller when redshift increases from z = 0.3 to z = 1. Thus the integration time could be reduced significantly and gas rich clusters at intermediate redshifts can be detected by FAST in less than 2 hours of integration time. For the local Universe, we have also used SAM simulations to create mock catalogs of clusters to predict the outcomes from FAST all sky surveys. Comparing with the optically selected catalogs derived by cross matching the galaxy catalogs from the SDSS survey and the ALFALFA survey, we find that the HI mass distribution of the mock catalog with 20 s of integration time agrees well with that of observations. However, the mock catalog with 120 s of integration time predicts many more groups and clusters that contain a population of low mass HI galaxies not detected by the ALFALFA survey. A future deep HI blind sky survey with FAST would be able to test such prediction and set constraints on the numerical simulation models. The observational strategy and sample selections for future FAST observations of galaxy clusters at high redshifts are also discussed.

关键词： galaxy clusters -- neutral hydrogen (HI) -- galaxy evolution