著者

Fumihiro CHINA Naoki TAKEUCHI Hideo SUZUKI Yuki YAMANASHI Hirotaka TERAI Nobuyuki YOSHIKAWA

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE TRANSACTIONS on Electronics (ISSN:09168516)

巻号頁・発行日

vol.E105-C, no.6, pp.264-269, 2022-06-01

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The adiabatic quantum flux parametron (AQFP) is an energy-efficient, high-speed superconducting logic device. To observe the tiny output currents from the AQFP in experiments, high-speed voltage drivers are indispensable. In the present study, we develop a compact voltage driver for AQFP logic based on a Josephson latching driver (JLD), which has been used as a high-speed driver for rapid single-flux-quantum (RSFQ) logic. In the JLD-based voltage driver, the signal currents of AQFP gates are converted into gap-voltage-level signals via an AQFP/RSFQ interface and a four-junction logic gate. Furthermore, this voltage driver includes only 15 Josephson junctions, which is much fewer than in the case for the previously designed driver based on dc superconducting quantum interference devices (60 junctions). In measurement, we successfully operate the JLD-based voltage driver up to 4 GHz. We also evaluate the bit error rate (BER) of the driver and find that the BER is 7.92×10-10 and 2.67×10-3 at 1GHz and 4GHz, respectively.

著者

Yuki YAMANASHI Shohei NISHIMOTO Nobuyuki YOSHIKAWA

出版者

The Institute of Electronics, Information and Communication Engineers

雑誌

IEICE TRANSACTIONS on Electronics (ISSN:09168516)

巻号頁・発行日

vol.E99-C, no.6, pp.692-696, 2016-06-01

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A single-flux-quantum (SFQ) arithmetic logic unit (ALU) was designed and tested to evaluate the effectiveness of introducing dynamically reconfigurable logic gates in the design of a superconducting logic circuit. We designed and tested a bit-serial SFQ ALU that can perform six arithmetic/logic functions by using a dynamically reconfigurable AND/OR gate. To ensure stable operation of the ALU, we improved the operating margin of the SFQ AND/OR gate by employing a partially shielded structure where the circuit is partially surrounded by under- and over-ground layers to reduce parasitic inductances. Owing to the introduction of the partially shielded structure, the operating margin of the dynamically reconfigurable AND/OR gate can be improved without increasing the circuit area. This ALU can be designed with a smaller circuit area compared with the conventional ALU by using the dynamically reconfigurable AND/OR gate. We implemented the SFQ ALU using the AIST 2.5kA/cm2 Nb standard process 2. We confirmed high-speed operation and correct reconfiguration of the SFQ ALU by a high-speed test. The measured maximum operation frequency was 30GHz.

著者

Chunfen Zhang Sota Sato Tatsuro Tsukuni Mamoru Sato Hatsuhiko Okada Toshiya Yamamoto Masato Wada Shogo Matsumoto Nobuyuki Yoshikawa Naozumi Mimida Kaori Takagishi Manabu Watanabe Qiufen Cao Sadao Komori

出版者

一般社団法人 園芸学会

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.MI-094, (Released:2016-04-26)

被引用文献数

3

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To select cultivars to produce doubled haploids (DHs) efficiently in an anther culture, a total of 28 apple cultivars (25 cultivars and 3 rootstock cultivars) were investigated to assess their callus formation rate, embryo formation rate, shoot formation rate from embryo and efficiency of shoot multiplication and acclimatization. The callus formation rates of ‘Red Astrachan’, ‘Kinsei’, ‘Tsugaru’, ‘Golden Delicious’ (‘GD’), ‘American Summer Pearmain’ (‘ASP’), ‘Gala’, ‘Rome Beauty’, and ‘Jonathan’ were high, but ‘JM2’ and ‘King of Tompkins’ formed no callus. Regarding the embryo formation rates, ‘ASP’, ‘Rome Beauty’, ‘M.9’, and ‘Starking Delicious’ (‘SD’) were high, but ‘GD’, ‘JM2’, ‘King of Tompkins’, ‘Ralls Janet’, and ‘Smith’s Cider’ formed no embryo. Regarding the shoot formation rate from embryos, ‘Senshu’, ‘Tsugaru’, and ‘Sansa’ showed high values, but ‘Fuji’, ‘Jonathan’, and ‘Wijcik’ did not form shoots at all. The rate of shoot formation from anthers showed a high–low order of ‘Senshu’, ‘SD’, ‘ASP’, and ‘Tsugaru’. Multiplication and acclimatization of the shoots were not easy. Many individuals died. Eventually, only ‘Senshu’ and ‘SD’ acclimatized. Therefore, cultivars that produced DHs efficiently were ‘Senshu’ and ‘SD’. The results indicated that all processes of “embryo formation”, “shoot induction”, and “shoot multiplication and acclimatization” are important for obtaining DHs in apple anther cultures.