Papers by Satoshi Nakamoto
Plasma and Fusion Research, 2019
Nihon Chikusan Gakkaiho, 1995
The invention provides a switching power supply unit which can suppress the deviation of the star... more The invention provides a switching power supply unit which can suppress the deviation of the start time of the slope compensation. The switching power supply device comprises a slope compensation circuit which is used for suppressing subharmonic oscillation according to a timing signal from the oscillation circuit (7) . The oscillating circuit (7) includes a first circuit(M1- M9, C2, Vref, 27) generating signals with a basic oscillation frequency, and a second circuit (29, 31 , 33) of the time signals generated by logic processing of the fundamental ocilalating frequency signals.
2008 IEEE Custom Integrated Circuits Conference, 2008
Substrate noise analysis has become increasingly important in recent LSI design. This is because ... more Substrate noise analysis has become increasingly important in recent LSI design. This is because substrate noise, which affects PLLs, causes jitter that results in timing error. Conventional analysis techniques of substrate noise are, however, impractical for large-scale designs that have hundreds of millions of transistors because the computational complexity is too huge. To solve this problem, we have developed a
Journal of Reproduction and Development, 1993
Plasma and Fusion Research, 2019
This document specifies the base 58 encoding scheme, including an introduction to the benefits of... more This document specifies the base 58 encoding scheme, including an introduction to the benefits of the approach, the encoding and decoding algorithm, alternative alphabets, and security considerations.
The Bitcoin ecosystem has grown tremendously in recent years. While the main sectors of growth an... more The Bitcoin ecosystem has grown tremendously in recent years. While the main sectors of growth and venture capital funding have been infrastructure for the Bitcoin ecosystem itself as well as financial services, there is also a more recent evolution in sectors beyond financial services. We classify the venture-capital backed start up ecosystem accordingly and present its evolution over time. Thereby, we identify interesting sectors, i.e. digital assets, marketplaces, and notary services. Each sector is further subdivided, and six representative venture-backed start-up companies are presented in comprehensive case studies. We extract the core innovations and Bitcoin features on which these are based. Finally, we critically discuss their disruptive potential.
Plasma and Fusion Research, 2020
To recover the energy of fast protons created in D-3 He fusion, a secondary electron (SE) direct ... more To recover the energy of fast protons created in D-3 He fusion, a secondary electron (SE) direct energy converter was proposed, in which protons penetrated aligned metal foil electrodes, and their energy was converted into that of emitted SEs. Simulated experiments showed the problem of energy recovery of the SEs, which arose because of the magnetic mirror effect disturbing the arrival of SEs at collectors in the guiding magnetic field. To solve this problem, we propose the use of ring-type magnets to realize lower mirror ratio structures. As a result, better energy recovery is obtained for low mirror ratios because a larger part of the energy of the SEs is converted into components parallel to the magnetic field, which correspond to the direction normal to the surface of the collector.
Fusion Engineering and Design, 2018
The structure of secondary electron (SE) direct energy converter (SEDEC), which was proposed as a... more The structure of secondary electron (SE) direct energy converter (SEDEC), which was proposed as an additional energy recovery device settled in the downstream of traveling wave direct energy converter for D-3 He fusion, was investigated to improve its performance. Additional electron collectors (A-ECs) were settled near foil electrodes for quick collection of SEs. As the location of the A-ECs was close to the proton beam, scattered protons were incident on the A-ECs, leading to a decrease in the net electron current. Blocking plates were used to suppress incident of protons. The net electron current recovered and overcame the level measured in the conventional structure. The recovered power increased by 75%.
Plasma and Fusion Research, 2016
As an energy recovery device for fast protons produced in D-3 He nuclear fusion, secondary electr... more As an energy recovery device for fast protons produced in D-3 He nuclear fusion, secondary electron (SE) direct energy converter (SEDEC) was proposed in addition to traveling wave direct energy converter (TWDEC). Some protons passing through a TWDEC come into an SEDEC, where protons penetrate to a number of foil electrodes and emitted SEs are recovered. Following to a development of SE orbit control by magnetic field, dependence on incident angle of protons was examined to optimize structure of SEDEC. Based on a theoretical expectation, experiments were performed by changing incident angle of protons and variation in emission and energy recovery were measured. Both emission and energy recovery increased as the angle increased, and differences with theoretical expectation are discussed.
Plasma and Fusion Research, 2015
A traveling wave direct energy converter (TWDEC) is expected to be used as an energy recovery dev... more A traveling wave direct energy converter (TWDEC) is expected to be used as an energy recovery device for fast protons produced during the D-3 He nuclear fusion reaction. Some protons, however, are not fully decelerated and pass through the device. A secondary electron direct energy converter (SEDEC) was proposed as an additional device to recover the protons passing through a TWDEC. In our previous study, magnetic field was applied for efficient secondary electron (SE) collection, but the SEs were reflected close to the collector due to the magnetic mirror effect and the collection was degraded. Herein, a new arrangement of magnets is proposed to be set away from the collector, and experiments in various conditions are performed. An appropriate arrangement away from the collector resulted in the improvement of SE collection.
IEEJ Transactions on Fundamentals and Materials, 1996
To prevent severe faults in GIS, studies on the relation between UV irradiation and degradation o... more To prevent severe faults in GIS, studies on the relation between UV irradiation and degradation of insulating material are presented. By using the measurement system of discharge-light-emission , quantitative measurement of the discharge light is carried out, and the absolute emission power of the discharge is obtained. On the one hand, the degradation of insulating material is evaluated employing sample materials which are irradiated by a UV-laser. The result is obtained that the volume or the surface resistance decreases as the amount of irradiation increases .
Fusion Science and Technology, 2015
With an aim to improve the total efficiency of a D-3 He nuclear fusion direct energy conversion s... more With an aim to improve the total efficiency of a D-3 He nuclear fusion direct energy conversion system, a secondary electron direct energy converter (SEDEC) is proposed. The incident high-energy protons in an SEDEC penetrate a large number of foil electrodes aligned in the direction of the proton beam, and emitted secondary electrons are recovered. The results of the initial experiments showed that most of the secondary electrons flowed into anteroposterior electrodes and did not arrive at the electron collector located alongside and perpendicular to the direction of the proton beam. A magnetic field was introduced to push the electrons toward the electron collector, but it was not effective for energy recovery. This technical note analyzes the trajectories of electrons in the presence of the magnetic field and proposes and examines a revised arrangement of permanent magnets. The arrangement of the magnets along one side of the proton beam greatly improved the energy recovery; however, the recovery level was lower than that without magnets.
IEEJ Transactions on Electronics, Information and Systems, 2007
Non-member For the treatment of cancer using hyperthermia, high frequency electromagnetic fields ... more Non-member For the treatment of cancer using hyperthermia, high frequency electromagnetic fields are used to heat the cancer cells. These electromagnetic fields fall into two general frequency ranges, one relatively low, and the other in the microwave range. Both produce some side effects such as the heating of healthy cells or the impact on the body of invasive surgery required to expose deep-lying cells. To reduce these side reactions, the use of lower microwave frequencies with phase control was proposed. In this paper, we present a very basic study to prove the viability of the proposed scheme. This includes the selection of a suitable frequency, demonstration of localized heating using the selected frequency, and a three-dimensional numerical analysis of the electromagnetic fields involved. In the heating demonstration, a tissue-equivalent phantom made from agar was irradiated by phase-controlled electromagnetic waves from a pair of circular patch antennas operating at 430 MHz. This produced localized heating. The numerical analysis produced a field distribution that corresponded closely to the results from the heating experiment. It confirmed that the phase control technique for long-wavelength microwaves was effective in producing localized heating.
In laser fusion scheme, uniform laser irradiation is important. A stalk which supports a pellet a... more In laser fusion scheme, uniform laser irradiation is important. A stalk which supports a pellet affects uniformity. In our laboratory, Magnetically Suspended Pellet (MSP) which is a non-contact technique to suspend a Ni coated pellet has been studied. Coating, characterization and also charge-and-supply are described for the MSP. The first description is about coating Ni thin film on a pellet.
Journal of Reproduction and Development, 1992
Caffeine is known to improve sperm motility and fertilizing ability in vitro [1-6]. Hence this dr... more Caffeine is known to improve sperm motility and fertilizing ability in vitro [1-6]. Hence this drug has been widely used as a sperm-stimulant additive to in vitro fertilization medium in domestic animals [7-11]. Niwa and Ohgoda [12] reported that caffeine and heparin elevated the rate of penetrated oocytes synergistically in fertilization in vitro in the cattle. Caffeine also accelerates the
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Papers by Satoshi Nakamoto