香港大学预科

Four new bistable twisted nematic liquid crystal display (BTN-LCD) modes with no n crossed polarizers are developed for the first time. Most of them present high contrast ratio and high transmittance with high stability; some display between black and white states, the performance reaches the level of twist nematic liqu id crystal display device. They are better than those modes using crossed polari zers presented before.

In this paper, the control of delaying period-doubling bifurcations and unstable periodic orbits embedded in a chaotic attractor of a discrete nonlinear dynamical system is effectively realized by using the state variables feedback and parameter variation. Moreover, the 2n periodic orbits of the system can be controlled into the　2m (m

Measuring system and method as well as data processing of the laser intensity modulation method(LIMM) have been set up.The polarization distribution and the process of depolarization for VDF/TrFE ferroelectric copolymers are investigated by LIMM.The pyroe

SiC buried layers were snythesized by a metal vapor vacuum arc ion source,with C+ ions implanted into crystalline Si substrates.According to X-ray photoelectron spectroscopy,the characteristic electron energy loss spectra of the SiC buried layers were studied.It was found that the characteristic electron energy loss spectra depend on the profiles of the carbon content,and correlate well with the order of the buried layers.