Tatsuya Hagiwara

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Recent studies on traffic measurement analysis in the various networks have shown that packet traffic exhibits Long Range Dependent properties called Self-Similarity. Some papers reported that Self-Similarity degrades the network performance, such as buffer overflow. Thus, we need new network control considering Self-Similar properties. Network control(More)
The syntheses of [2]- and [3]catenanes by olefin metathesis and oxidative acetylide coupling have been studied in detail. Pseudorotaxanes that were obtained by mixing crown ether and ammonium salts containing two terminal reactive end-groups were converted to [2]- and [3]catenane. Their yields were influenced not only by the chain length of the ammonium(More)
Using high-speed scanning atomic force microscopy, we directly observed single-molecular enzymatic elongation of hyaluronan polymer chains at intervals of 10 s on a mica or lipid bilayer surface, on which Pasteurella multocida hyaluronic acid synthase (pmHAS) was immobilized. The reaction was started by the addition of both UDP-glucuronic acid and(More)
A 15GHz 4-channel transmit/receive RF core-chip is presented for high SHF wide-band massive MIMO in 5G. Both phase shifters (PS) and variable gain amplifiers (VGA) with high resolution and high accuracy are integrated in each TX and RX path of the chip. A calibration technique to compensate the error of 6bit PS caused by I/Q mismatch in the poly phase(More)
Combined experiments of high power ion cyclotron heating and ion acceleration in a magnetic nozzle are performed in order to develop an advanced plasma propulsion system for the manned space mission. Ion heating is clearly observed in hydrogen plasma as well as in helium plasma, where those light ions are preferable for high specific impulse operation of(More)
In this paper, an L-band transmitter and receiver MMIC, which is known as a core chip for phased array communication and radar applications is presented. The MMIC is fabricated in 0.18 μm SiGe-BiCMOS process, comprises an RX amplifier, a 5-bit active phase shifter, SPDT switches, and a TX amplifier. The RX amplifier realized low noise and high(More)
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