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Educational Practices in the Model of Music Learning Theory of E. Edwin Gordon: An Observational Research 被引量:1
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作者 Antonella Nuzzaci 《Journal of Literature and Art Studies》 2013年第5期263-277,共15页
This paper analyzes the supervision activity, to which educators and teachers enrolled with AIGAM (Gordon Italian Association for the Musical Learning) are subject to every year and intends to verify the application... This paper analyzes the supervision activity, to which educators and teachers enrolled with AIGAM (Gordon Italian Association for the Musical Learning) are subject to every year and intends to verify the application of those principles expressed in the learning model of the MLT (Music Learning Theory) developed by educational psychologist E. Edwin Gordon (1989, 1999, 2000, 2001, 2007) and promoted internationally by various institutions and organizations specifically accredited. It describes the influence of the videotaped supervision on the process, functions of monitoring, and evaluation of educational practices, starting with an empirical model that has guided the interventions in a study of supervision on training aimed at consolidating and developing professional skills in music education in early childhood. This paper sought to understand: the kind of practices, interactions, communications developing during an educational actions, the existence of a consistent relationship between the principles expressed in the MLT and their application, the type and benefits of supervision performed by of video recording on stakeholders in terms of change in professional behavior, and finally whether the active supervision could be comparable with other kinds of approaches. 展开更多
关键词 music education MLT (Music Learning theory empirical research in music education observational tool
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Observational Features of Large-Scale Structures as Revealed by the Catastrophe Model of Solar Eruptions
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作者 Jun Lin National Astronomical Observatories/Yunnan Observatory, Chinese Academy of Sciences, Kunming 650011 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2007年第4期457-476,共20页
Large-scale magnetic structures are the main carrier of major eruptions in the solar atmosphere. These structures are rooted in the photosphere and are driven by the unceasing motion of the photospheric material throu... Large-scale magnetic structures are the main carrier of major eruptions in the solar atmosphere. These structures are rooted in the photosphere and are driven by the unceasing motion of the photospheric material through a series of equilibrium configurations. The motion brings energy into the coronal magnetic field until the system ceases to be in equilibrium. The catastrophe theory for solar eruptions indicates that loss of mechanical equilibrium constitutes the main trigger mechanism of major eruptions, usually shown up as solar flares, eruptive prominences, and coronal mass ejections (CMEs). Magnetic reconnection which takes place at the very beginning of the eruption as a result of plasma instabilities/turbulence inside the current sheet, converts magnetic energy into heating and kinetic energy that are responsible for solar flares, and for accelerating both plasma ejecta (flows and CMEs) and energetic particles. Various manifestations are thus related to one another, and the physics behind these relationships is catastrophe and magnetic reconnection. This work reports on recent progress in both theoretical research and observations on eruptive phenomena showing the above manifestations. We start by displaying the properties of large-scale structures in the corona and the related magnetic fields prior to an eruption, and show various morphological features of the disrupting magnetic fields. Then, in the framework of the catastrophe theory, we look into the physics behind those features investigated in a succession of previous works, and discuss the approaches they used. 展开更多
关键词 Sun: large-scale magnetic structures - Sun: eruptive processes - Sun: theory and observations - magnetic reconnection and current sheets
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Alternative kind of hydrogen atoms as a possible explanation for the latest puzzling observation of the 21 cm radio line from the early Universe 被引量:1
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作者 Eugene Oks 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2020年第7期172-176,共5页
There is a puzzling astrophysical result concerning the latest observation of the absorption profile of the redshifted radio line 21 cm from the early Universe(as described in Bowman et al.). The amplitude of the prof... There is a puzzling astrophysical result concerning the latest observation of the absorption profile of the redshifted radio line 21 cm from the early Universe(as described in Bowman et al.). The amplitude of the profile was more than a factor of two greater than the largest predictions. This could mean that the primordial hydrogen gas was much cooler than expected. Some explanations in the literature suggested a possible cooling of baryons either by unspecified dark matter particles or by some exotic dark matter particles with a charge a million times smaller than the electron charge. Other explanations required an additional radio background. In the present paper, we entertain a possible different explanation for the above puzzling observational result: the explanation is based on the alternative kind of hydrogen atoms(AKHA),whose existence was previously demonstrated theoretically, as well as by the analysis of atomic experiments. Namely, the AKHA are expected to decouple from the cosmic microwave background(CMB) much earlier(in the course of the Universe expansion) than usual hydrogen atoms, so that the AKHA temperature is significantly lower than that of usual hydrogen atoms. This seems to lower the excitation(spin) temperature of the hyperfine doublet(responsible for the 21 cm line) sufficiently enough for explaining the above puzzling observational result. This possible explanation appears to be more specific and natural than the previous possible explanations. Further observational studies of the redshifted 21 cm radio line from the early Universe could help to verify which explanation is the most relevant. 展开更多
关键词 Cosmology:Early Universe explanation of the puzzle of 21cm radio line Galaxies:intergalactic medium Cosmology:observations Cosmology:theory
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La Shalle's invariant-set-theory based asymptotic synchronization of duffing system with unknown parameters
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作者 禹东川 吴爱国 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第1期95-99,共5页
A novel La Shalle's invariant set theory (LSIST) based adaptive asymptotic synchronization (LSISAAS) method is proposed to asymptotically synchronize Duffing system with unknown parameters which also are consider... A novel La Shalle's invariant set theory (LSIST) based adaptive asymptotic synchronization (LSISAAS) method is proposed to asymptotically synchronize Duffing system with unknown parameters which also are considered as system states. The LSISASS strategy depends on the only information, i.e. one state of the master system. According to the LSIST, the LSISASS method can asymptotically synchronize fully the states of the master system and the unknown system parameters as well. Simulation results also validate that the LSISAAS approach can obtain asymptotic synchronization. 展开更多
关键词 chaotic synchronization adaptive state observer La Shalle's invariant set theory
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Classical Theory of Advance of Perihelion of Mercury with Velocity Dependent Inertial and Gravitational Masses
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作者 Erich R. Bagge (Institute for Pure and Applied Nuclear Physics, Christian Albrechts University, Kiel,Germany) 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 1995年第4期87-98,共12页
It is shown that Mercury's motion of the perihelion around the Sun, which is believed to be explicable quantitatively only by general relativity, can be fully understood within the frame of the dynamics of special... It is shown that Mercury's motion of the perihelion around the Sun, which is believed to be explicable quantitatively only by general relativity, can be fully understood within the frame of the dynamics of special relativity. It is only necessary to take into consideration the relativistic dependence of the planet's inertial and gravitational masses on its velocity (relative to the Sun) in the conservation equations for energy, and linear and angular momenta in the gravitational field. The physical Problem is reduced to a singular, nonlinear differential equation, which is solved numerically for the planet Mercury. The advance of the perihelion of Mercury is shown to be = 42.087' for a period of 100 years, which is in agreement with the as- tronomical observations and the result (by analytical approximations) of general relativity. 展开更多
关键词 Planet mercury Advance of perihelion Classical theory Velocity dependent inertial and gravitational masses Agreement with observations.
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Chaplygin gas of Tachyon Nature Imposed by Noether Symmetry and constrained via H(z)data
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作者 Lucas Gardai Collodel Gilberto Medeiros Kremer 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2016年第4期113-120,共8页
An action of general form is proposed for a Universe containing matter, radiation and dark energy. The latter is interpreted as a tachyon field non-minimally coupled to the scalar curvature. The Palatini approach is u... An action of general form is proposed for a Universe containing matter, radiation and dark energy. The latter is interpreted as a tachyon field non-minimally coupled to the scalar curvature. The Palatini approach is used when varying the action so the connection is given by a more generic form. Both the self-interaction potential and the non-minimally coupling function are obtained by constraining the system to present invariability under global point transformation of the fields (Noether Symmetry). The only possible solution is shown to be that of minimal coupling and constant potential (Chaplygin gas). The behavior of the dynamical properties of the system is compared to recent observational data, which infers that the tachyon field must indeed be dynamical. 展开更多
关键词 cosmology: cosmological parameters -- cosmology: theory -- cosmology: observations --dark energy
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Efficiency of Managers as Role Models:A Social Learning Theory Perspective
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作者 Myrto Boumpouri Michael Galanakis 《Psychology Research》 2022年第12期933-938,共6页
This systematic literature review aimed to analyze and synthesize studies that indicated the importance of behavioral observation in the organizational context.Based on Social Learning Theory and by considering releva... This systematic literature review aimed to analyze and synthesize studies that indicated the importance of behavioral observation in the organizational context.Based on Social Learning Theory and by considering relevant recent findings and theories,the impact of managers as role models for employees is researched and analyzed.The importance of this topic is to determine ways that learning and enhancing performance in the workplace can be applied for people management development.The literature for theory was numerous,however studies on the particular topic were limited and not expanded in the organizational context.The key message of this review is that the impact of managers and leaders can be positive and progressive both for the employees and for the organization. 展开更多
关键词 social learning theory role modeling management developmental leadership observational learning behavioral learning
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General Relativity as the Classical Limit of the Renormalizable Gauge Theory of Volume Preserving Diffeomorphisms
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作者 Christian Wiesendanger 《Journal of Modern Physics》 2014年第10期948-958,共11页
The different roles and natures of spacetime appearing in a quantum field theory and in classical physics are analyzed implying that a quantum theory of gravitation is not necessarily a quantum theory of curved spacet... The different roles and natures of spacetime appearing in a quantum field theory and in classical physics are analyzed implying that a quantum theory of gravitation is not necessarily a quantum theory of curved spacetime. Developing an alternative approach to quantum gravity starts with the postulate that inertial energy-momentum and gravitational energy-momentum need not be the same for virtual quantum states. Separating their roles naturally leads to the quantum gauge field theory of volume-preserving diffeomorphisms of an inner four-dimensional space. The classical limit of this theory coupled to a quantized scalar field is derived for an on-shell particle where inertial energy-momentum and gravitational energy-momentum coincide. In that process the symmetry under volume-preserving diffeomorphisms disappears and a new symmetry group emerges: the group of coordinate transformations of four-dimensional spacetime and with it General Relativity coupled to a classical relativistic point particle. 展开更多
关键词 QUANTUM Gravity QUANTUM Gauge theory of Volume-Preserving DIFFEOMORPHISM Group GR Emerging AS the Classical LIMIT of Above Different Roles of Inertial and Gravitational Momentum Observability of Spacetime at Microscopic Level
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Measuring observability by generalized information theoretic quantities
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作者 Badong CHEN Jinchun HU Hongbo LI Zengqi SUN 《控制理论与应用(英文版)》 EI 2008年第3期233-238,共6页
A normalized measure is established to provide the quantitative information about the degree of observability for the discrete-time, stochastically autonomous system. This measure is based on the generalized informati... A normalized measure is established to provide the quantitative information about the degree of observability for the discrete-time, stochastically autonomous system. This measure is based on the generalized information theoretic quantities (generalized entropy, mutual information) of the system state and the observations, where the system state can be a discrete or a continuous random vector. Some important properties are presented. For the linear case, the explicit formula for the degree of observability is derived, and the equivalence between the proposed measure and the traditional rank condition is proved. The curves for the degree of observability are depicted in a simple example. 展开更多
关键词 Stochastic system OBSERVABILITY Information theory
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The Impact of a Heterogeneous Surface on Spatiotemporal Uncertainties of Sensible Heat, Latent Heat, and CO<sub>2</sub>Flux Measured over the Secondary Forest
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作者 Nanami Sakai Daisuke Komori +1 位作者 Masafumi Kon Wonsik Kim 《Journal of Water Resource and Protection》 2020年第3期171-182,共12页
The turbulent fluxes, such as sensible and latent heat fluxes and CO2 flux, are globally observed over various terrestrial areas in order to understand the interaction between biosphere and atmosphere. Although the tu... The turbulent fluxes, such as sensible and latent heat fluxes and CO2 flux, are globally observed over various terrestrial areas in order to understand the interaction between biosphere and atmosphere. Although the turbulent flux observations are generally performed on a horizontally homogeneous surface, the spatial distribution of the soil moisture is not homogeneous even on cultivated land with homogeneous vegetation, indicating that the development of each plant would be different and that the plant physiology, such as photosynthesis and growth, would be heterogeneous. In this study, to clarify the impact of a heterogeneous surface on spatiotemporal uncertainty of turbulent fluxes, a simultaneous flux observation experiment was conducted at different heights (20 m and 30 m) above the ground surface in a secondary seasonal tropical forest located in the Tak Province, Thailand. We defined ε as the spatial uncertainty of the turbulent flow flux, as proposed by Kim et al. (2011b) [1], and observed that ε of CO2 flux was high, whereas ε of sensible and latent heat fluxes were low. This is likely to be caused by spatial uncertainty such as a heterogeneous surface. The CO2 environment was heterogeneous;however, sensible and latent heat environments were homogeneous because the source area received insolation uniformly. Therefore, the analytical results for the CO2 flux presented a different pattern from those exhibited by the analytical results of the latent and sensible heat fluxes. 展开更多
关键词 EDDY COVARIANCE Fractional Uncertainty Monin-Obukhov Similarity theory Simultaneous Flux observation
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What do parameterized Om(z) diagnostics tell us in light of recent observations?
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作者 Jing-Zhao Qi Shuo Cao +4 位作者 Marek Biesiada Teng-Peng Xu Yan Wu Si-Xuan Zhang Zong-Hong Zhu 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2018年第6期49-58,共10页
In this paper, we propose a new parametrization for Om(z) diagnostics and show how the most recent and significantly improved observations concerning the H(z) and SN Ia measurements can be used to probe the consistenc... In this paper, we propose a new parametrization for Om(z) diagnostics and show how the most recent and significantly improved observations concerning the H(z) and SN Ia measurements can be used to probe the consistency or tension between the ΛCDM model and observations. Our results demonstrate that H0 plays a very important role in the consistency test of ΛCDM with H(z)data. Adopting the Hubble constant priors from Planck 2013 and Riess, one finds considerable tension between the current H(z) data and ΛCDM model and confirms the conclusions obtained previously by others. However, with the Hubble constant prior taken from WMAP9, the discrepancy between H(z) data and ΛCDM disappears, i.e., the current H(z) observations still support the cosmological constant scenario. This conclusion is also supported by the results derived from the Joint Lightcurve Analysis(JLA) SN Ia sample. The best-fit Hubble constant from the combination of H(z)+JLA(H00 = 68.81+1.5-1.49 km s-1 Mpc-1) is very consistent with results derived both by Planck 2013 and WMAP9, but is significantly different from the recent local measurement by Riess. 展开更多
关键词 cosmology: theory cosmology: observations cosmology: cosmological parameters
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A synchrotron self-Compton scenario for the very high energy γ-ray emission of the intermediate BL Lacertae object W Comae
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作者 Jin Zhang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2009年第7期777-782,共6页
W Comae has significant variability in multi-wavelengthes, from radio to gamma-ray bands. A bright outburst in optical and X-ray bands was observed in 1998, and most recently, a strong TeV flare was detected by VERITA... W Comae has significant variability in multi-wavelengthes, from radio to gamma-ray bands. A bright outburst in optical and X-ray bands was observed in 1998, and most recently, a strong TeV flare was detected by VERITAS in 2008. It is the first TeV intermediate-frequency-peaked BL Lacertae source. I find that both the broadband spectral energy distributions (SEDs) which were quasi-simultaneously obtained during the TeV flare and during the optical/X-ray outburst are well fit by using a single-zone synchrotron + synchrotron-self-Compton model. The satisfactory fitting requires a large beaming factor, i.e., δ- 25 and δ- 20 for the TeV flare and the optical/X-ray outburst, respectively, suggesting that both the optical/X-ray outburst and the TeV flare are from a relativistic jet. The size of the emission region of the TeV flare is three times larger than that of the optical/X-ray outburst, and the strength of the magnetic field for the TeV flare is - 14 times smaller than that of the X-ray/optical outburst, likely indicating that the region of the TeV flare is more distant from the core than that of the X-ray/optical outburst. The inverse Compton component of the TeV flare peaks around 1.3 GeV, but it is around 20 MeV for the X-ray/optical outburst, lower than that for the TeV flare by two orders of magnitude. The model predicts that the optical/X-ray outburst might be accompanied by a strong MeV/GeV emission, but the TeV flare may be not associated with the X-ray/optical outburst. The GeV emission is critical for characterizing the SEDs of the optical/X-ray outburst and the TeV flare. The predicted GeV flux is above the sensitivity of Fermi/LAT, and it could be verified with the observations by Fermi/LAT in the near future. 展开更多
关键词 BL Lacertae objects: individual: W Comae - gamma-rays observations - gamma-rays theory - radiation mechanisms non-thermal
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Searching for α variation and cosmic acceleration in the generalized BSBM theory with tachyonic potential
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作者 Hossein Farajollahi Fatemeh Tayebi 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2015年第2期191-198,共8页
Abstract We consider the BSBM (Bekenstein, Sandvik, Barrow and Magueijo) cos- mological model in the presence of tachyon potential with the aim of studying the sta- bility of the model and test it against observatio... Abstract We consider the BSBM (Bekenstein, Sandvik, Barrow and Magueijo) cos- mological model in the presence of tachyon potential with the aim of studying the sta- bility of the model and test it against observations. The phase space analysis shows that from fourteen critical points that represent the state of the universe, only one is stable. With a small perturbation, the universe transits from a state of unstable deceleration to stable acceleration. The stability analysis combined with the best fitting process imposes constraints on the cosmological parameters that are in agreement with ob- servation. In the BSBM theory, the variation of fundamental constants is driven from variation of a scalar field. The tachyonic scalar field, responsible for both variation of fundamental constants and universal acceleration, is reconstructed. 展开更多
关键词 cosmology:theory—cosmology:observations—cosmological parameters
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Cosmological parameters for spatially flat dust filled Universe in Brans-Dicke theory
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作者 Gopi Kant Goswami 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2017年第3期55-66,共12页
We have investigated late time acceleration for a spatially fiat dust filled Universe in Brans- Dicke theory in the presence of a positive cosmological constant A. Expressions for Hubble's constant, luminosity distan... We have investigated late time acceleration for a spatially fiat dust filled Universe in Brans- Dicke theory in the presence of a positive cosmological constant A. Expressions for Hubble's constant, luminosity distance and apparent magnitude have been obtained for our model. The theoretical results are compared with observed values of the latest 287 high redshift (0.3 ≤ z ≤1.4) Type Ia supernova data taken from the Union 2.1 compilation to estimate present values of matter and dark energy parame- ters, (Ωm)0 and (ΩA)0. We have also estimated the present value of Hubble's constant H0 in light of an updated sample of Hubble parameter measurements including 19 independent data points. The results are found to be in good agreement with recent astrophysical observations. We also calculated various physical parameters such as matter and dark energy densities, present age of the Universe and decelera- tion parameter. The value for Brans-Dicke-coupling constant ω is set to be 40 000 based on accuracy of solar system tests and recent experimental evidence. 展开更多
关键词 COSMOLOGY osmological parameters - cosmology observations- dark energy-Brans-Dicke theory
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Leader-following formation control of multi-agent networks based on distributed observers 被引量:4
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作者 罗小元 韩娜妮 关新平 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第10期7-15,共9页
To investigate the leader-following formation control, in this paper we present the design problem of control protocols and distributed observers under which the agents can achieve and maintain the desired formation f... To investigate the leader-following formation control, in this paper we present the design problem of control protocols and distributed observers under which the agents can achieve and maintain the desired formation from any initial states, while the velocity converges to that of the virtual leader whose velocity cannot be measured by agents in real time. The two cases of switching topologies without communication delay and fixed topology with time-varying communication delay are both considered for multi-agent networks. By using the Lyapunov stability theory, the issue of stability is analysed for multi-agent systems with switching topologies. Then, by considering the time-varying communication delay, the sufficient condition is proposed for the multi-agent systems with fixed topology. Finally, two numerical examples are given to illustrate the effectiveness of the proposed leader-following formation control protocols. 展开更多
关键词 formation control distributed observer multi-agent system graph theory
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Analyses of geographical observations in the Heihe River Basin: Perspectives from complexity theory 被引量:4
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作者 Gao Jianbo FANG Peng YUAN Lihua 《Journal of Geographical Sciences》 SCIE CSCD 2019年第9期1441-1461,共21页
Since 2005,dozens of geographical observational stations have been established in the Heihe River Basin(HRB),and by now a large amount of meteorological,hydrological,and ecological observations as well as data pertain... Since 2005,dozens of geographical observational stations have been established in the Heihe River Basin(HRB),and by now a large amount of meteorological,hydrological,and ecological observations as well as data pertaining to water resources,soil and vegetation have been collected.To adequately analyze these available data and data to be further collected in future,we present a perspective from complexity theory.The concrete materials covered include a presentation of adaptive multiscale filter,which can readily determine arbitrary trends,maximally reduce noise,and reliably perform fractal and multifractal analysis,and a presentation of scale-dependent Lyapunov exponent(SDLE),which can reliably distinguish deterministic chaos from random processes,determine the error doubling time for prediction,and obtain the defining parameters of the process examined.The adaptive filter is illustrated by applying it to obtain the global warming trend and the Atlantic multidecadal oscillation from sea surface temperature data,and by applying it to some variables collected at the HRB to determine diurnal cycle and fractal properties.The SDLE is illustrated to determine intermittent chaos from river flow data. 展开更多
关键词 Heihe River BASIN GEOGRAPHICAL observation complexity theory adaptive multiscale filter FRACTAL analysis scale-dependent LYAPUNOV EXPONENT
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Trajectory Tracking of Vertical Take-off and Landing Unmanned Aerial Vehicles Based on Disturbance Rejection Control 被引量:4
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作者 Lu Wang Jianbo Su 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI 2015年第1期65-73,共9页
We investigate the trajectory tracking problem of vertical take-off and landing (VTOL) unmanned aerial vehicles (UAV), and propose a practical disturbance rejection control strategy. Firstly, the nonlinear error model... We investigate the trajectory tracking problem of vertical take-off and landing (VTOL) unmanned aerial vehicles (UAV), and propose a practical disturbance rejection control strategy. Firstly, the nonlinear error model is established completely by the modified Rodrigues parameters, while considering dynamics of the servo actuators. Then, a hierarchical control scheme is applied to design the translational and rotational controllers based on the time-scale property of each subsystem, respectively. And the linear extended state observer and auxiliary observer are used to deal with the uncertainties and saturation. At last, global stability of the closed-loop system is analyzed based on the singular perturbation theory. Simulation results show the effectiveness of the proposed control strategy. © 2014 Chinese Association of Automation. 展开更多
关键词 Aircraft control AIRSHIPS Closed loop control systems Closed loop systems Disturbance rejection LANDING Perturbation techniques State estimation TAKEofF Trajectories Unmanned vehicles VEHICLES
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Foreground removal of 21cm fluctuation with multifrequency fitting
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作者 Li-Ping He 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2009年第6期653-664,共12页
The 21 centimeter (21 cm) line emission from neutral hydrogen in the intergalactic medium (IGM) at high redshifts is strongly contaminated by foreground sources such as the diffuse Galactic synchrotron emission an... The 21 centimeter (21 cm) line emission from neutral hydrogen in the intergalactic medium (IGM) at high redshifts is strongly contaminated by foreground sources such as the diffuse Galactic synchrotron emission and free-free emission from the Galaxy, as well as emission from extragalactic radio sources, thus making its observation very complicated. However, the 21 cm signal can be recovered through its structure in frequency space, as the power spectrum of the foreground contamination is expected to be smooth over a wide band in frequency space while the 21 cm fluctuations vary significantly. We use a simple polynomial fitting to reconstruct the 21 cm signal around four frequencies 50, 100, 150 and 200 MHz with an especially small channel width of 20 kHz. Our calculations show that this multifrequency fitting approach can effectively recover the 21 cm signal in the frequency range 100 - 200 MHz. However, this method doesn't work well around 50 MHz because of the low intensity of the 21 cm signal at this frequency. We also show that the fluctuation of detector noise can be suppressed to a very low level by taking long integration times, which means that we can reach a sensitivity of ≈ 10 mK at 150 MHz with 40 antennas in 120 hours of observations. 展开更多
关键词 COSMOLOGY theory observations diffuse radiation -- methods data analysis
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Probing the Lambda-DGP Braneworld model
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作者 Arvin Ravanpak Hossein Faraiollahi Golnaz Fadakar 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2016年第9期31-38,共8页
We study cosmic dynamics in the context of the normal branch of the DGP braneworld model. Using current Planck data, we find the best fitting model and associated cosmological parameters in non-fiat ADGP. With the tra... We study cosmic dynamics in the context of the normal branch of the DGP braneworld model. Using current Planck data, we find the best fitting model and associated cosmological parameters in non-fiat ADGP. With the transition redshift as a basic variable and statefinder parameters, our result shows that the Universe starts its accelerated expansion phase slightly earlier than expected in ACDM cosmology. The result also alleviates the coincidence problem of the ACDM model. 展开更多
关键词 (cosmology:) cosmological parameters -- observations -- theory -- dark energy -- methods numerical
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A Tired Light/Contracting Universe Model from the Union2.1 Supernovae Data
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作者 John Glover 《Journal of Modern Physics》 2017年第2期147-155,共9页
A tired light/contracting universe (TLCU) model is shown to be an excellent fit to the redshift/distance modulus data for the 580 supernovae 1a in the Union2.1 compilation. The data reveal that the Milky Way is in a s... A tired light/contracting universe (TLCU) model is shown to be an excellent fit to the redshift/distance modulus data for the 580 supernovae 1a in the Union2.1 compilation. The data reveal that the Milky Way is in a static region with a radius of about 450 Mpc. Beyond the static region the universe is contracting with a space velocity which is linearly proportional to distance over the whole range of the data (K=&minus;7.6&plusmn;2.3km&sdot;s&minus;1&sdot;Mpc&minus;1). The other constant of the model is the Hubble constant for which a value of H=69.51&plusmn;0.86 km&sdot;s&minus;1&sdot;Mpc&minus;1 is obtained. The fit of the TLCU model to the Union2.1 data is at least as good as the fit of the two constant ΛCDM model to the same data. A formula for photon travel distance is derived and an experiment for the possible detection of the tired light process is proposed. 展开更多
关键词 COSMOLOGY observationS theory
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