Sun Li-juan

Boosting ridge extreme learning machine

Extreme Learning Machine (ELM) was proposed recently for efficiently training single-hidden-layer feed forward neural networks (SLFNs). However, this algorithm often requires a large number of hidden nodes and sometimes performs unstable. In this paper, a novel training algorithm called boosting ridge extreme learning machine (BR-ELM) is proposed which can construct stable generalization performance with a compact network with boosting ridge regression. In the experiments, the BR-ELM remains robust to all the test data and performs stable and response fast with much less nodes.

Soft X-Ray Magneto-optical Faraday Effect around Ni M2,3 Edges

We present magneto-optical (MO) Faraday spectra measured around the M2,3 edges (60–70eV) of Ni films at the Beijing Synchrotron Radiation Facility (BSRF). A polarization analysis of the final state of the transmitted radiation from the Ni film is employed to determine the Faraday rotation at the edges. The MO effect becomes resonantly enhanced at the M2,3 edges, and accordingly large values for the rotation angle β of 1.85 ± 0.19° for this ferromagnetic Ni film with thickness of 31 nm are measured. Without the magnetic field, the azimuthal angles do not shift; with parallel and antiparallel magnetic field the rotation angles shift in the opposite way and they are symmetrical. The uncertainty of Faraday rotation angles mainly comes from the data fitting and the state change of the beamline when the angles are measured.

Performance of a polarizer using synthetic mica crystal in the 12–25 nm wavelength range

To develop polarizer functioning in the extreme ultraviolet (EUV) and soft X-ray region, the polarization performance of synthetic mica has been investigated theoretically with a simulation code using Fresnel equations and optical constants from the Henke database. The reflectance of synthetic mica crystal for s and p polarization was measured to investigate its polarization performance in a home-made synchrotron radiation soft X-ray polarimeter at beamline 3W1B, Beijing Synchrotron Radiation Facility (BSRF). The reflectivity of the synthetic mica crystal at an angle of grazing incidence of 48° was obtained from the experimental data, which is about 4.8×10−3 at 25 nm and 6.0×10−4 at 12 nm, and the linear polarizance of the X-ray reflected by the synthetic mica crystal that we measured using an analyzer-rotating method increases from 80% to 96.6% in this EUV region, while higher than 98.2% in the simulation. The result indicates that this synthetic mica crystal works as a practical polarizer in this EUV region of 12–25 nm, and also in an extensive wavelength region higher than 25 nm.