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Recent advances in non-radiative wireless power transfer (WPT) technique essentially relying on magnetic resonance and near-field coupling have successfully enabled a wide range of applications. However, WPT systems based on double resonators are severely limited to short- or mid-range distance, due to the deteriorating efficiency and power with long transfer distance. WPT systems based on multi-relay resonators can overcome this problem, which, however, suffer from sensitivity to perturbations and fabrication imperfections. Here, we experimentally demonstrate a concept of topological wireless power transfer (TWPT), where energy is transferred efficiently via the near-field coupling between two topological edge states localized at the ends of a one-dimensional radiowave topological insulator. Such a TWPT system can be modelled as a parity-time-symmetric Su-Schrieffer-Heeger (SSH) chain with complex boundary potentials. Besides, the coil configurations are judiciously designed, which significantly suppress the unwanted cross-couplings between nonadjacent coils that could break the chiral symmetry of the SSH chain. By tuning the inter- and intra-cell coupling strengths, we theoretically and experimentally demonstrate high energy transfer efficiency near the exceptional point of the topological edge states, even in the presence of disorder. The combination of topological metamaterials, non-Hermitian physics, and WPT techniques could promise a variety of robust, efficient WPT applications over long distances in electronics, transportation, and industry.

We present and analyze the possibility of using optical ${\it u}$-band luminosities to estimate star-formation rates (SFRs) of galaxies based on the data from the South Galactic Cap ${\it u }$ band Sky Survey (SCUSS), which provides a deep ${\it u}$-band photometric survey covering about 5000 $deg^2$ of the South Galactic Cap. Based on two samples of normal star-forming galaxies selected by the BPT diagram, we explore the correlations between ${\it u}$-band, H$\alpha$, and IR luminosities by combing SCUSS data with the Sloan Digital Sky Survey (SDSS) and ${\it Wide}$-${\it field\ Infrared\ Survey\ Explorer}$ (${\it WISE}$). The attenuation-corrected ${\it u}$-band luminosities are tightly correlated with the Balmer decrement-corrected H$\alpha$ luminosities with an rms scatter of $\sim$ 0.17 dex. The IR-corrected ${\it u }$ luminosities are derived based on the correlations between the attenuation of ${\it u}$-band luminosities and ${\it WISE}$ 12 (or 22) $\mu$m luminosities, and then calibrated with the Balmer-corrected H$\alpha$ luminosities. The systematic residuals of these calibrations are tested against the physical properties over the ranges covered by our sample objects. We find that the best-fitting nonlinear relations are better than the linear ones and recommended to be applied in the measurement of SFRs. The systematic deviations mainly come from the pollution of old stellar population and the effect of dust extinction; therefore, a more detailed analysis is needed in the future work., Comment: 10 pages, 11 figures, 1 table; accepted for publication in ApJ

This paper presents multicolor optical photometry of the nearby galaxy cluster Abell 119 (z = 0:0442) with the Beijing-Arizona-Taiwan-Connecticut (BATC) system of 15 intermediate bands. Within the BATC viewing field of 58'* 58', there are 368 galaxies with known spectroscopic redshifts, including 238 member galaxies (called sample I). Based on the spectral energy distributions (SEDs) of 1376 galaxies brighter than iBATC = 19:5, photometric redshift technique and the color-magnitude relation of earlytype galaxies are applied to select faint member galaxies. As a result, 117 faint galaxies were selected as new member galaxies. Combined with sample I, an enlarged sample (called sample II) of 355 member galaxies is obtained. Spatial distribution and localized velocity structure for two samples demonstrate that A119 is a dynamically complex cluster with at least three prominent substructures in the central region within 1 Mpc. A large velocity dispersion for the central clump indicates a merging along the line of sight. No significant evidences for morphology and luminosity segregations are found in both samples. With the evolutionary synthesis model PEGASE, environmental effect on the star formation properties is confirmed. Faint galaxies in low-density region tend to have longer time scales of star formation, smaller mean stellar ages, and lower metallicities of interstellar medium, which is in agreement with the context of hierarchical cosmological scenario., Comment: 21 pages, 11 figures and 4 tables. Accepted for publication in RAA

Bell nonlocality, entanglement and nonclassical correlations are different aspects of quantum correlations for a given state. There are many methods to measure nonclassical correlations. In this paper, nonclassical correlations in two-qubit spin models are measured by use of measurement-induced disturbance (MID) [Phys. Rev. A, 77, 022301 (2008)] and geometric measure of quantum discord (GQD) [Phys. Rev. Lett. 105, 190502 (2010)]. Their dependencies on external magnetic field, spin-spin coupling, and Dzyaloshinski-Moriya (DM) interaction are presented in detail. We also compare Bell nonlocality, entanglement measured by concurrence, MID and GQD and illustrate their different characteristics., Comment: 1 text and 5 eps figures, accepted by Annals of Physics

Quantum correlation in two-qubit spin models is investigated by use of measurement-induced disturbance [S. Luo, Phys. Rev. A, 77(2008) 022301]. Its dependences on external magnetic field, spin-spin coupling, and Dzyaloshinski-Moriya (DM) interactions are presented in detail. We also compare measurement-induced disturbance and thermal entanglement in spin models and illustrate their different characteristics., Comment: 6 eps figures

In this paper we present a multicolor photometry for A2589 ($z=0.0414$) with 15 intermediate bands in the Beijing-Arizona-Taiwan-Connecticut (BATC) system which covers an optical wavelength range from 3000 \AA\ to 10000 \AA. The spectral energy distributions (SEDs) for more than 5000 sources are achieved down to {\it V} $\sim$ 20 mag in about 1 deg$^{2}$ field. A2589 has been also covered by the Sloan Digital Sky Survey (SDSS) in photometric mode only. A cross-identification of the BATC-detected galaxies with the SDSS photometric catalog achieves 1199 galaxies brighter than $i=19.5$ mag, among which 68 member galaxies with known spectroscopic redshifts are found. After combining the SDSS five-band photometric data and the BATC SEDs, the technique of photometric redshift is applied to these galaxies for selecting faint member galaxies. The color-magnitude relation is taken as a further restriction of early-type cluster galaxies. As a result, 106 galaxies are newly selected as member galaxies. Spatial distribution of member galaxies shows a north-south elongation which agrees with the X-ray brightness profile and the orientation of central cD galaxy, NGC 7647. No substructures are detected on the basis of positions and radial velocities of cluster galaxies, indicating that A2589 is a well-relaxed system. The luminosity function of A2589 exhibits a peak at $M_{R} \sim -20$ mag and a dip at $M_{R} \sim -19 $ mag. The low-density outer regions are the preferred habitat of faint galaxies. With the evolutionary population synthesis model, PEGASE, the environmental effect on the star formation properties for 68 spectroscopically confirmed member galaxies is studied. The outlier faint galaxies tend to have longer time scales of star formation, shorter mean stellar ages, and lower metallicities of interstellar medium, which can be interpreted in the context of hierarchical cosmological scenario., Comment: 2011 Accepted to AJ

We show a spin superconductor (SSC) in ferromagnetic graphene as the counterpart to the charge superconductor, in which a spin-polarized electron-hole pair plays the role of the spin $2 (\hbar/2)$ `Cooper pair' with a neutral charge. We present a BCS-type theory for the SSC. With the `London-type equations' of the super-spin-current density, we show the existence of an electric `Meissner effect' against a spatial varying electric field. We further study a SSC/normal conductor/SSC junction and predict a spin-current Josephson effect., Comment: 6 pages, 4 figures

We report the results of a time-series CCD photometric survey of variable stars in the field of the open cluster NGC 2126. In about one square degree field covering the cluster, a total number of 21 variable candidates are detected during this survey, of which 16 are newly found. The periods, classifications and spectral types of 14 newly discovered variables are discussed, which consist of six eclipsing binaries systems, three pulsating variable stars, three long period variables, one RS CVn star, and one W UMa or $\delta$ Scuti star. In addition, there are two variable candidates, the properties of which cannot be determined in this paper. By a method based on fitting spectral energy distributions(SEDs) of stars with theoretical ones, the membership probabilities and the fundamental parameters of this cluster are determined. As a result, five variables are probably members of NGC 2126. The fundamental parameters of the this cluster are determined as: the metallicity to be 0.008 $Z_\odot$, the age $\log(t)$= 8.95, the distance modulus $(m-M)_{0}$= 10.34 and the reddening value $E(B-V)$=0.55 mag., Comment: 12 pages, accepted for publication in RAA

We investigate the dynamical properties of electroencephalogram (EEG) signals of human in sleep. By using a modified random walk method, We demonstrate that the scale-invariance is embedded in EEG signals after a detrending procedure. Further more, we study the dynamical evolution of probability density function (PDF) of the detrended EEG signals by nonextensive statistical modeling. It displays scale-independent property, which is markedly different from the turbulent-like scale-dependent PDF evolution., Comment: 4 pages and 6 figures

We present 13-band CCD intermediate-band spectrophotometry of a field centered on the open cluster NGC 7789 from 400 to nearly 1000 nm, taken with Beijing-Arizona-Taiwan-Connecticut (BATC) Multi-Color Survey photometric system. By comparing observed spectral energy distributions of NGC 7789 stars with theoretical ones, the fundamental parameters of this cluster are derived: an age of $1.4\pm0.1$ Gyr, a distance modulus $(m-M)_{0}=11.27\pm0.04$, a reddening $E(B-V)=0.28\pm0.02$, and a metallicity with the solar composition $Z=0.019$. When the surface density profile for member stars with limiting magnitudes of 19.0 in the BATC $e$ band ($\lambda_{\textrm{eff}}=4925$ \AA) is fitted by King model, the core radius $R_{c}=7.52\arcmin$ and the tidal radius $R_{t}=28.84\arcmin$ are derived for NGC 7789. The observed mass function (MF) for main sequence stars of NGC 7789 with masses from 0.95 to 1.85 $M_{\odot}$ is fitted with a power-law function $\phi(m)\propto m^{\alpha}$ and the slope $\alpha=-0.96$ is derived. Strong mass segregation in NGC 7789 is reflected in the significant variation of the concentration parameters $C_{0}=\log (R_{t}/R_{c})$ for member stars of NGC 7789 within different mass ranges: $C_{0}=1.02$ for most of massive stars; $C_{0}=0.37$ for the lowest-mass MS stars. Strong mass segregation in NGC 7789 is also indicated in the significant variation of the slopes $\alpha$ in different spatial regions of the cluster: the MF for stars within the core region has $\alpha=-0.71$, much flatter than that for stars in external regions of the cluster ($\alpha=-1.20$)., Comment: 24 pages. AJ accepted

Beijing-Arizona-Taiwan-Connecticut (BATC) multi-band photometric data in the field of open cluster M48 are used to determine its membership. By comparing observed spectral energy distributions (SEDs) of stars with theoretical ones, membership probabilities of 750 stars with limiting magnitude of 15.0 in BATC $c$ band ($\lambda_{eff}=4194$ \AA) are determined. 323 stars with membership probabilities higher than 30% are considered as candidate members of M48. Comparing membership probabilities of 229 common stars obtained by the present method and the proper-motion based methods, a 80% agreement among these methods is obtained., Comment: 27 pages,7figures, accepted for publication in PASP

This paper presents 13 color CCD intermediate-band spectrophotometry of a field centered on the open cluster M48 (NGC 2548), from 400nm to nearly 1000nm, taken with Beijing-Arizona-Taiwan-Connecticut (BATC) Multi-Color Survey Photometric system. The fundamental parameters of this cluster are derived with a new method which based on the comparison between the spectral energy distributions (SEDs) of cluster stars and the theoretical SEDs of Padova models. We find that the best-fitting age of M48 is 0.32 Gyr, the distance is 780 pc and a reddening E(B-V)=0.04 with a solar metallicity Z=0.019, Comment: 17 pages, 2 figures, will appear in the January 2005 issue of PASP

In the comment by Konig, Gefen, and Silva, their main point is to question the approximation we used in solving the Green's function. They believe that this approximative method is inappropriate to describe spin-flip-related dephasing processes caused by intradot interaction, so they believe that our conclusions are ill-founded because of that. We agree that we indeed used an approximation in calculating the Green's function. However, we believe our approximation to be reasonable and the main conclusion, namely, an intradot electron-electron interaction can not induce dephasing, should hold. In particular, we emphasize that we have taken the higher-order terms in solving the Green's function than appeared in their previous publications. We will compare the approximation used their papers with that in our work., Comment: 2 pages, 1 figure

Based on synthetic flux spectra calculated from theoretical atmospheric models, a calibration of temperature and metallicity for the dwarfs observed in the Beijing-Arizona-Taiwan-Connecticut (BATC) multicolor photometric system is presented in this paper. According to this calibration, stellar effective temperatures can be obtained from some temperature-sensitive color indices. The sample stars have colors and magnitudes in the ranges 0.15 kpc, it could not be interpreted according to the different contributions from the three components because of the large uncertainty. So it is possible that there is little or no gradient for z>5 kpc. The overall distribution shows a metallicity gradient d[Fe/H]/dz=-0.17+-0.04dex/kpc for z<15 kpc., Comment: 22 pages, 9 figure, accepted by Astronomical Journal

We investigate the degree of coherence of electronic transport through a quantum dot (QD) in the presence of an intradot electron-electron interaction. By using an open multi-terminal Aharonov-Bohm (AB) setup, we find that the intradot interaction does not induce any dephasing effect and the electron transport through the QD is fully coherent. We also observe that the asymmetric amplitude of the AB oscillation in the conductance through the two-terminal AB setup originates from the interplay between the confined structure and the electron-electron interaction. Thus, one can not associate a dephasing process with this asymmetric amplitude, as has been done in previous studies., Comment: 4 pages, 3 figures