ABSTRACT
The " V -shaped switching" mode in high polarization ferroelectric liquid crystals was studied with the aim of stabilizing the monostable bookshelf structure with the spontaneous polarization parallel to the glass plates. The director field in such cells was confirmed to be sensitive to both the liquid crystal properties and the cell parameters. In cells with only polyimide alignment layers, hysteresis free switching was never obtained, with bistable and asymmetric monostable structures compromising the zero-field dark state and preventing an ideal, hysteresis-free analog response. By incorporating a SiO(2) layer between the ITO electrode and the polyimide, the undesired states were suppressed and essentially hysteresis-free switching was obtained for driving frequencies in the range 0.2-200 Hz . Cells rubbed only on one side give more uniform alignment than cells rubbed on both sides but their inherent asymmetry shifts the long-term dark state away from 0 V and causes the response to gray level voltage modulation to be slightly asymmetric. The formation of different types of states as a function of the values of the surface parameters, and the observed stabilization of the V -shaped switching structure by the dielectric surface layers, are in good agreement with an earlier analysis by Copic [Phys. Rev. E 65, 021701 (2002)].
ABSTRACT
Nowadays people very often seek health information on the Internet. They use electronic mail, mailing and news groups as well as web services. Internet allows to acquire quick answers to almost all questions. It can be anonymous. The use of Internet is fairly cheap. The answer of each Internet question causes ethical and the moral problems. An expert has no direct contact with an ill person. He does not know if the person who asked is ill or wants to receive information about someone else. People ask about diseases which they or their families suffer from. They ask about drugs they take or they will take, about side-effects, interactions and prices. Some questions are asked by students, doctors and other people who are interested in psychiatry. Internet is an enormous place, where patients and doctors search for and obtain information.