A Novel UWB Pulse Shape Modulation System

In this paper novel modified Hermite polynomial functions for use in impulse radio (ultra-wideband) communications are proposed. With these functions pulse shapes which are orthogonal and have nearly constant pulse width regardless of the pulse order are generated. These properties hold under the effects of differentiation. An M-ary communication system is constructed using these pulse shapes. A Matlab model for generating the pulses is designed and the effect of timing jitter on the performance of the system is investigated by computer simulation.     

A Study of Shadowing on Indoor Visible-Light Wireless Communication Utilizing Plural White LED Lightings

White LED is considered as a strong candidate for the future lighting technology. We have proposed an optical wireless communication system that employs white LEDs for indoor wireless networks. In this system, LED is used not only as a lighting device, but also as a communication device. The transmitter has large optical power and large emission characteristics to function as lighting device. And the system has specific wireless channel impulse response differing from infrared wireless communication. In this paper, we discuss about shadowing effect on the system utilizing plural LED lightings including the performance of ISI based on the impulse response. We consider the downlink transmission based on TDMA and evaluate the shadowing effect caused by pedestrians with computer simulation. When the shadowing often occurs at 800 Mb/s, the performance of outage call duration rate and blocking rate are improved by using 3 LED lightings compared with 1 or 2 LED lightings. And, we show that the system with the optimal number of the LED lighting is robust against shadowing and can accommodate more calls. Toshihiko Komine was born in Shizuoka, Japan, on November 17, 1978. He received the B.E. and M.E. degrees in Information and Computer Science from Keio University, Yokohama, Japan, in 2001 and 2003 respectively. He is currently studying for the Ph.D. degree at Department of Information and Computer Science, Keio University. His current research interests are optical wireless communications and LED communications. Shinichiro Haruyama is a professor at Department of Information and Computer Science, Faculty of Science and Technology, Keio University, Yokohama, Japan. He received an M.S. in engineering science from University of California at Berkeley in 1983 and a Ph.D. in computer science from the University of Texas at Austin in 1990. He worked for Bell Laboratories of AT{&}T and Lucent Technologies, U.S.A from 1991 to 1996, and for Sony Computer Science Laboratories, Inc. from 1998 to 2002. His research interests include reconfigurable system, system design automation, wireless communication, and visible light communication. Masao Nakagawa was born in Tokyo, Japan in 1946. He received the B.E., M.E. and Ph.D. degrees in electrical engineering from Keio University, Yokohama, Japan, in 1969, 1971 and 1974 respectively. Since 1973, he has been with the Department of Electrical Engineering, Keio University, where he is now a Professor. His research interests are in CDMA, consumer Communications, Mobile communications, ITS (Intelligent Transport Systems), Wireless Home Networks, and Visible light Communication. He received 1989 IEEE Consumer Electronics Society Paper Award, 1999-Fall Best Paper Award in IEEE VTC, IEICE Achievement Award in 2000, IEICE Fellow Award in 2001. He was the executive committee chairman on International Symposium on Spread Spectrum Techniques and Applications in 1992 and the technical program committee chairman of ISITA (International Symposium on Spread Spectrum Techniques and Applications) in 1994. He is an editor of Wireless Personal Communications and was a guest editor of the special issues on “CDMA Networks I, II, III and IV” published in IEEE JSAC in 1994 (I and II) and 1996 (III and IV). He chairs the Wireless Home Link sub-committee in MMAC (Multimedia Mobile Access Communication Promotion Committee).     

New ring-opening polymerization via a π-allylpalladium complex

Summary A binary system of a palladium complex as catalyst and zinc alkoxide as initiator conducted a novel ring-opening polymerization of cyclic carbonate, i. e., 5,5-dimethyl-4-ethenyl-1,3-dioxan-2-one. The polymerization proceeded along with releasing carbon dioxide to produce the corresponding polyether. The -allylpalladium complex generated from the monomer with the catalyst is the key intermediate for this new polymerization. The propagating end is zinc alkoxide, which nucleophilically attacks the monomer activated as the -allylpalladium complex in the propagation.     

Nanocrystallization of Pd74Si18Au8 metallic glass

The crystallization process of Pd₇₄Si₁₈Au₈ amorphous alloy has been investigated by transmission electron microscopy, small angle X-ray scattering and three-dimensional atom probe techniques. Although literature suggests that the alloy decomposes into two glassy phases prior to the crystallization, we found that the crystallization occurs directly from a single amorphous phase by the primary crystallization of fcc Pd–Au solid solution, followed by the polymorphous crystallization of the remaining amorphous phase to a Pd₃Si phase.     

纯镍钝化膜的电化学性能

为了搞清镍的钝化行为,本文用极化曲线法及交流阻抗技术,通过对纯镍在中性H₃BO₃-Na₂B₄O₇溶液及添加了K₃Fe(CN)₆/K₄Fe(CN)₆氧化-还原系溶液中的极化行为及交流阻抗特性的研究,讨论了钝化膜的电模型和电极反应。     

Evaluation of Young’s modulus of imprinted hydrogen silsesquioxane pillar after residual layer removal by reactive ion etching

Nanoimprint lithography has two basic steps. The first is the imprint step in which a mold with nanostructures on its surface is pressed into a resin film on a substrate, followed by removal of the mold. The second step is the residual layer removal by a reactive ion etching (RIE). There is no report whether the properties of the imprinted structure after RIE change or not. In this work, the authors evaluated the Young’s modulus of the imprinted pillar after residual layer removal by RIE. In this experiment, hydrogen silsesquioxane (HSQ), a type of spin-on-glass, was used as an imprint material. The residual layer was etched by RIE using CHF₃ gas. The Young’s modulus of imprinted pillar after RIE was measured via cantilever method. The Young’s modulus of HSQ pillar after RIE was twice as much as that of HSQ pillar before RIE. From the Fourier transform infrared measurement, it was founds the chemical structure of HSQ was changed by forming network structure due to heating by RIE plasma energy. These results indicate that the mechanical property of imprinted structure was changed in the residual layer removal step by using RIE.     

Fabrication of fluorine-terminated diamond-like carbon thin film using a hyperthermal atomic fluorine beam

Surface modification of diamond-like carbon (DLC) film was performed using a hyperthermal atomic fluorine beam on the purpose of production of hydrophobic surface by maintaining the high hardness of DLC film. By the irradiation of atomic fluorine beam of a 1.0 × 10²⁰ atoms/cm², the contact angle of a water drop against the DLC surface increased from 73° to 111°. The formation of CF₃, CF₂ and CF bonding on the modified DLC surface was confirmed from the measurements of X-ray photoelectron spectra and near-edge X-ray absorption fine structure spectra. Irradiation of hyperthermal atomic fluorine beam was concluded to produce insulator fluorine-terminated DLC film, which has high F content on the surface, by the taking of the use of neutral atomic beam as a fluorine source.     

Health-related quality of life varies with personality types: a comparison among cancer patients, non-cancer patients and healthy individuals in a Japanese population

In an attempt to examine differential effects of personality on health-related quality of life (HRQoL) without regard to disease type, we used the HRQoL-20, a general questionnaire (Japanese original scale) we developed (comprising 20 questions related to physiological, psychological or social HRQoL) and the Eysenck Personality Questionnaire (EPQ), which measures personality traits of extraversion (E), neuroticism (N) and psychoticism (P). The subjects (399 males and 429 females), stomach cancer patients, non-cancer patients (who had received acupuncture or moxibustion treatment) and healthy controls, were classified into three personality types. The results indicated that the HRQoL score of the tolerable/tolerant type (high E, low N and high P scorers) was greater than the intolerable/intolerant type (low E, high N and low P scorers) and also the unclassified type (neither of above scorers). The HRQoL correlated positively with the E and P scales and negatively with the N scale, in the case of all subjects, with the exception of N in male cancer patients and E in male non-cancer patients. The results supported the hypothesis that the HRQoL varies with personality variables, in that each patient, in different treatment settings, strives for the situation that is congruent with his/her personality to attain a better HRQoL.     

The potential distribution in local cells on corroding metals

In the galvanic corrosion, the distribution of potential within the electrolyte was calculated for the condition that each local cell is independent and there is no interaction between the local cells. This analysis on the problem extended the Waber's treatment, and the distribution of potential was obtained for each local cell.