出版者
Institute of Electrical and Electronics Engineers
雑誌
IEEE Journal of Selected Topics in Quantum Electronics (ISSN:1077260X)
巻号頁・発行日
vol.12, no.1, pp.71-77, 2006
被引用文献数
47

We demonstrate coupled-mode characteristics and bistability in photonic molecule lasers composed of evanescent-coupled GaInAsP twin microdisks. First, we show room-temperature continuous-wave operation by photopumping and discuss the unique behavior of coupled modes, i.e., the anticrossing and splitting characteristics of bonding and antibonding modes. Next, we present the clear bistability, which is observed for the antibonding mode by nonuniform pumping with an effective power of nearly 40 mu W. It is explained by rate equation analysis, which assumes saturable absorption. The analysis also predicts mode switching by the carrier-induced refractive index change. A micron-sized device with a very low power consumption will allow large scale integration of optical memories, optical flip-flops, and so forth.
著者
Sasao Tsutomu Butler J.T.
出版者
Institute of Electrical and Electronics Engineers
雑誌
Transactions on Computers (ISSN:00189340)
巻号頁・発行日
vol.50, no.9, pp.935-948, 2001-09
被引用文献数
1 21

In an irredundant sum-of-products expression (ISOP), each product is a prime implicant (Pl) and no product can be deleted without changing the function. Among the ISOPs for some function f, a worst ISOP (WSOP) is an ISOP with the largest number of Pls and a minimum ISOP (MSOP) is one with the smallest number. We show a class of functions for which the Minato-Morreale ISOP algorithm produces WSOPs. Since the ratio of the size of the WSOP to the size of the MSOP is arbitrarily large when it, the number of variables, is unbounded, the Minato-Morreale algorithm can produce results that are very far from minimum. We present a class of multiple-output functions whose WSOP size is also much larger than its MSOP size. For a set of benchmark functions, we show the distribution of ISOPs to the number of Pls. Among this set are functions where the MSOPs have almost as many Pls as do the WSOPs. These functions are known to be easy to minimize. Also, there are benchmark functions where the fraction of ISOPs that are MSOPs is small and MSOPs have many fewer Pls than the WSOPs. Such functions are known to be hard to minimize. For one class of functions, we show that the fraction of ISOPs that are MSOPs approaches 0 as n approaches infinity, suggesting that such functions are hard to minimize
著者
Kiyan Tsuyoshi Takade Maya Namihira Takao Hara Masanori Sasaki Mitsuru Goto Motonobu Akiyama Hidenori キヤン ツヨシ タカデ マヤ ナミヒラ タカオ ハラ マサノリ ササキ ミツル ゴトウ モトノブ アキヤマ ヒデノリ 喜屋武 毅 高出 麻耶 浪平 隆男 佐々木 満 後藤 元信 秋山 秀典
出版者
Institute of Electrical and Electronics Engineers
雑誌
IEEE transactions on plasma science
巻号頁・発行日
vol.36, no.3, pp.821-827, 2008-06
被引用文献数
4 33

This paper deals with the effect of the polarity and gap geometry on dc breakdown voltage characteristics of a pointto-plane gap in supercritical carbon dioxide (SC CO2) that is required to design a plasma reactor. In the experiments, the gap width d and the curvature radius of the point tip r were changed in the range of 80 to 300 μm and 50 to 170 μm respectively,and the CO2 state was controlled within the gas, liquid, and SC phases. The experimental results showed that a remarkable polarity effect appeared under certain gap conditions. As a result, it was found that negative polarity and a higher stressed electrode are desired conditions for the dc plasma reactor since an active corona supplying rich chemical radicals appears in SC CO2 under such conditions.
著者
Namihira Takao Tsukamoto Shunsuke Wang Douyan Hori Hideo Katsuki Sunao Hackam Reuben Akiyama Hidenori Shimizu Masaru Yokoyama Kenichi ナミヒラ タカオ ツカモト シュンスケ ホリ ヒデオ カツキ スナオ アキヤマ ヒデノリ シミズ マサル ヨコヤマ ケンイチ オウ トエン 浪平 隆男 勝木 淳 秋山 秀典 王 斗艶
出版者
Institute of Electrical and Electronics Engineers
雑誌
IEEE TRANSACTIONS ON PLASMA SCIENCE
巻号頁・発行日
vol.29, no.4, pp.592-598, 2001-08
被引用文献数
8 49

A short duration of 100-ns pulsed power has been used to remove nitric oxide (NO) in a mixture of nitrogen, oxygen, water vapor, and NO, simulating flue gases from a power station. The effects of the gas flow rate, the reactor length, and the pulse repetition rate on the percentage of NO removal and its energy efficiency are reported. The percentage of NO removal at a fixed gas flow rate increased with increasing pulse repetition rate due to the increased energy into the discharge. At a fixed pulse rate, the removal of NO increased with decreasing gas flow rate due to the increased residence time of the gas in the discharge reactor, thus facilitating the creation of increased radicals of O and N which then decreased NO. The energy removal efficiency of NO (in mol/kWh) decreased with increasing gas flow rate and increasing removal ratio of NO. The removal of NO increased with increasing energy density (J/I) input into the discharge at different reactor length.
著者
Wang Douyan Jikuya Manabu Yoshida Seishi Namihira Takao Katsuki Sunao Akiyama Hidenori オウ トエン ジクヤ マナブ ヨシダ セイシ ナミヒラ タカオ カツキ スナオ アキヤマ ヒデノリ 王 斗艶 軸屋 学 吉田 政史 浪平 隆男 勝木 淳 秋山 秀典
出版者
Institute of Electrical and Electronics Engineers
雑誌
IEEE transactions on plasma science
巻号頁・発行日
vol.35, no.4, pp.1098-1103, 2007-08
被引用文献数
6 80

A Blumlein generator that has a pulsewidth of 100 nswas used to investigate the process of streamer discharge propagationin a coaxial cylindrical reactor using a streak camera. Bothpositive and negative polarities of the streamer discharges wereperformed in air at atmospheric pressure. The results showed thatthe primary and secondary streamers propagated with increasingvelocity from the central rod to the outer cylinder electrode inboth positive and negative polarities of applied voltages to the rodelectrode. The propagation velocity of the streamer heads was inthe range of 0.8–1.2 mm/ns for a positive peak applied voltage inthe range of 43–60 kV and 0.6 mm/ns for a negative peak appliedvoltage of−93 kV, respectively. The electric field at streamer onsetwas calculated to be 12 and 20 MV/m for positive and negativeapplied voltages, respectively
著者
堀口 進
出版者
Institute of Electrical and Electronics Engineers
雑誌
IEEE/ACM Transactions on Networking
巻号頁・発行日
vol.11, no.6, pp.982-993, 2003
被引用文献数
4 32

科研費報告書収録論文(課題番号:14380138・基盤研究(B)(2)・14~16/研究代表者:堀口, 進 死亡(奥様 堀口悦子)/超高速ノンブロック・ネットワーク構成方式に関する研究)
著者
Wei Feng Chun Meng Dou Niwa M. Yamada K. Ohmori K.
出版者
Institute of Electrical and Electronics Engineers
雑誌
IEEE Electron Device Letters (ISSN:07413106)
巻号頁・発行日
vol.35, no.1, pp.3-5, 2014-01
被引用文献数
3

The influence of random telegraph noise (RTN) in MOSFETs on drain current (Id) during the rise/fall edges of the pulsed gate voltage (Vg) cycle was investigated. We have revealed for the first time that the existence of RTN increases Id fluctuations under dynamic Vg by making a comparison between FETs with and without RTN. The initial trap occupation states before varying Vg, which are governed by the RTN profiles, significantly affect the Id values during the rise/fall edges of Vg. The revealed effects of RTN with different profiles on Id under dynamic Vg will be useful for designing ultrahigh speed circuits.
著者
Obane H. Okajima K. Oozeki T. Ishii T.
出版者
Institute of Electrical and Electronics Engineers
雑誌
IEEE journal of photovoltaics (ISSN:21563381)
巻号頁・発行日
vol.2, no.3, pp.341-347, 2012-07
被引用文献数
40 10

Photovoltaic (PV) systems are often nonuniformly illuminated owing to shadows of neighboring buildings, trees, clouds, etc. In order to reduce the effect of shadows on solar panels, we propose the concept of a PV system with reconnection; this system consists of PV arrays that can be reconnected to minimize the mismatch loss, depending on the output of each of its module, measured at regular time intervals. In this study, the relationship between the output improvement with reconnection and the switching interval is shown. For a 3-kW PV system, under conditions of cloudlessness and cloudiness, a sharp difference in the output improvement relative to the switching interval is not observed. However, under the condition of shading, the output improvement sharply decreases relative to the switching interval; the output improvement at a 1-min switching interval is 0.15 kWh·h (+22.4%). For the 90-kW building-integrated photovoltaic system, during the summer solstice, a sharp difference in the output improvement relative to the switching interval is not observed. However, during the vernal equinox and winter solstice, when a large area of the PV system is shaded for a long period of time, the output improvement sharply decreases relative to the switching interval. The output improvement at a 1-min switching interval is 6.5 kWh·d (+2.9%) during the vernal equinox and 2.3 kWh·d (+3.7%) during winter solstice.