Sky location of massive black hole binaries in the foreground of Galactic white dwarf binaries

For space-based gravitational wave(GW)detection,the main noise source for massive black hole binaries(MBHBs)is attributed to approximately 107 double white dwarf binaries in the foreground.For a GW source,the amplitude of the detector response,recorded by a space-based gravitational wave detector,exhibits a modulation effect with a year period when observing the source from various orbital positions.Under the adverse conditions mentioned above,where there is a strong foreground noise and annual modulation in the signals,we employed the wavelet transform and the strong-amplitude relevant orbital position search methods,which allows the weak MBHB sources to achieve higher locating accuracy.In detail,for two MBHB sources of lower intensity,the precision of luminosity distance,represented by the ratioΔD_(L)/D_(L) at the 95%confidence level,is enhanced by factors of∼2.The angular resolutions,denoted byΔΩs,are enhanced by a factor of∼20.These improvements increase the number of detectable GW sources,facilitate multi-messenger follow-up observations and provide constraints on the cosmological constant.

Estimation of far-field wavefront error of tilt-to-length distortion coupling in space-based gravitational wave detection

In space-based gravitational wave detection, the estimation of far-field wavefront error of the distorted beam is the precondition for the noise reduction. Zernike polynomials are used to describe the wavefront error of the transmitted distorted beam. The propagation of a laser beam between two telescope apertures is calculated numerically. Far-field wavefront error is estimated with the absolute height of the peak-to-valley phase deviation between the distorted Gaussian beam and a reference distortion-free Gaussian beam. The results show that the pointing jitter is strongly related to the wavefront error. Furthermore, when the jitter decreases 10 times from 100 nrad to 10 nrad, the wavefront error reduces for more than an order of magnitude. In the analysis of multi-parameter minimization, the minimum of wavefront error tends to Z[5,3] Zernike in some parameter ranges. Some Zernikes have a strong correlation with the wavefront error of the received beam. When the aperture diameter increases at Z[5,3] Zernike, the wavefront error is not monotonic and has oscillation.Nevertheless, the wavefront error almost remains constant with the arm length increasing from 10-1Mkm to 10~3Mkm.When the arm length decreases for three orders of magnitude from 10-1Mkm to 10-4Mkm, the wavefront error has only an order of magnitude increasing. In the range of 10-4Mkm to 10~3Mkm, the lowest limit of the wavefront error is from 0.5 fm to 0.015 fm at Z[5,3] Zernike and 10 nrad jitter.

Numerical model of planar heterojunction organic solar cells

We present a numerical study of the effects of the energy barrier between the lowest unoccupied molecular orbital of the acceptor layer and the cathode, the thicknesses of the donor layer and acceptor layer on the distributions of carrier density, the electric fields and the electric potentials of organic planar heterojunction solar cells. We obtained the quantitative dependencies of the distribution of carrier density, electric fields and the electric potentials on these quantities. The results provide a theoretical foundation for the experimental study of open-circuit organic planar heterojunction solar cells.

Machine Knowledge and Human Cognition

Intelligent machines are knowledge systems with unique knowledge structure and function.In this paper,we discuss issues including the characteristics and forms of machine knowledge,the relationship between knowledge and human cognition,and the approach to acquire machine knowledge.These issues are of great significance to the development of artificial intelligence.