In this letter, two OTAs with MOSFETs operating in the weak inversion region are proposed. One of the OTAs uses the exponential-logarithm transformation algorithm. Furthermore, the other realizes the high-linearity characteristics due to a small fluctuation of the common-terminal voltage of differential pair. The performance of the proposed OTAs was confirmed by HSPICE simulation.
This paper describes miniaturized 90 degree hybrid coupler using edge-coupled microstriplines. A high dielectric constant substrate (K=38) and high-density coupled-line configuration are adopted to realize small chip size. A conventional meandered coupled-line type and a new spiral coupled-line type were discussed for a high-density configuration. A bandwidth from 1.8 GHz to 3.6 GHz with /spl plusmn/0.5 dB power dividing balance and 90/spl plusmn/3 degrees phase difference were achieved with a chip size of 1.5/spl times/1.5 mm.
In recent years, the use of cross laminated timber (CLT) has been evolving. In addition, CLT manufactured with various species such as Japanese cedar has been developed to utilize the local resources in each country. However most factories in Japan produce CLT by bonding the laminae in width direction for orthogonal layers, where grain of element is perpendicular to the grain of outer layer, and this process is considered to be one of the factors that reduce productivity. A new wood based material (hereinafter referred to as Ply-lam) using wooden panel such as plywood for the orthogonal layer was developed in order to improve productivity in CLT manufacturing and improve quality. Japanese cypress lamina was used for the parallel layer, where grain of element is parallel to the grain of outer layer, of CLT and Korean larch plywood was used for the orthogonal layer, in order to effectively use Korean larch and expand the utilization of Japanese cypress. The cross-sectional construction of the Ply-lam was 5-layers 5-plies, and the dimensions were 1000 mm (width) × 150 mm (depth) × 4000 mm (length). As a performance evaluation of the manufactured Ply-lam, strength tests such as out-of-plane bending, in-plane bending, out-of-plane shearing and in-plane shearing tests were carried out. As the result of this study, Ply-lam composed of Japanese cypress lamina panels and Korean larch plywood showed very higher out-of-plane bending strength compared to the standard strength of CLT. And the result obtained in other tests seems to show a sufficiently high value.
In order to examine the impact sound insulation performance of building floors against heavy and soft impacts such as those of children jumping and running, a method whereby a heavy and impact source (an automobile tire) is dropped is specified in JIS A 1418, in addition to the standard method of using the ISO tapping machine. In order to improve the latter method, a research project has been carried out in the Architectural Institute of Japan. After various trial experiments, a new heavy and soft impact source (a rubber ball, weight: 2.5 kg; size: 183 mm in diameter; impact time: 20 ms) has been developed. In this paper, the basic impact characteristics of the source and the experimental results obtained in field measurements are introduced in comparison to the existing impact sources (automobile tire and the tapping machine).
Microwave low insertion loss SAW filters are realized by using ZnO epitaxial films on a sapphire substrate. The epitaxial growth conditions and dopant are carefully determined to realize low propagation loss and high stability. 1.5 to 2.5 GHz range SAW filters are fabricated with an insertion loss of only 1 to 2 dB and outline dimensions of 0.01 to 0.02 cc.
Conference paper written by Hitoshi Furuta, Masakatsu Kaneyoshi, Hiroshi Tanaka and Eiichi Watanabe presented at IABSE Conference: Cable-Supported Bridges - Challenging Technical Limits, Seoul, South Korea, 12-14 June 2001.
