2001) Retardation of the surface rearrangement of O2 plasma-treated LDPE by a two-step temperature Abstract-The effects of the specimen temperature of low-density polyethylene (LDPE) in O 2 plasma treatment were studied to enhance the amount of hydrophilic functional groups introduced and to reduce the aging effect. The specimen temperature was varied from 25 ± C to 100 ± C. The smallest water contact angle was obtained with the 45 ± C specimen and the largest amount of hydrophilic functional groups was introduced with the 100 ± C specimen, as determined by X-ray photoelectron spectroscopy (XPS). Therefore, a two-step plasma treatment with two different specimen temperatures, i.e. 100 ± C followed by 45 ± C, decreased the water contact angle and reduced the aging effect. It appears that the hydrophilic functional groups introduced were located at the specimen surface (about 0.5 nm) at low temperature and that the aging effect was reduced due to the hydrophilic functional groups formed inside (0.5-8 nm) at high specimen temperature. The aging rate and the diffusion coef cient were also estimated, depending on the specimen temperature, using the experimental aging data.

Microelectromechanical system (MEMS) represents an exciting new technology derived from the same fabricating processes used to make integrated circuits. The trends of growing importance of the wireless communications market is toward the system with minimal size, cost and power consumption. For the purpose of MEMS R&D used for wireless communications, a history and present situation of MEMS device development are reviewed in this paper, and an overview of MEMS research topics on RF communication applications and the state ofthe art technologies are also presented here.

In this paper, vibration suppression of an elastic beam fixed on a moving cart and carrying a concentrated or moving mass is considered. An input preshaping method with RIC (Robust Internal–loop Compensator) is proposed to suppress single mode residual vibration and to get accurate positioning of the beam–mass–cart system. The performance of the proposed input preshaping method is compared with that by previous ones by both numerical simulations and experiments. Using the proposed method, accurate PTP positioning of the moving mass without residual vibration is obtained experimentally by modifying the proposed input preshaping method. It is also able to suppress initial vibration of the beam–mass–cart system carrying a concentrated mass. Finally, the proposed input preshaping method is applied to the system to follow square trajectories of the moving mass without residual vibration.