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It is known that the hold-off voltages of vacuum gaps can be improved by the spark conditioning with repetitive electrical breakdowns. At the early stage of spark conditioning process, small pulse currents (not breakdowns) are sometimes observed, and in turn hold-off voltages were improved. To clarify the mechanism of the pulse current occurrence two experiments were carried out.
It is said that surface charging on insulator has an influence on vacuum surface discharge. To clarify mechanism of that event, it is necessary to investigate the progress of surface charge distribution on insulator during voltage application. In this research, real-time measurement of surface charge distributions on insulators (Alumina plate and PET film) in vacuum under AC voltage application was...
It has been known that the performance of hold-off voltage of vacuum breakdown for electrodes strongly depends on the surface contamination. Therefore, after manufacturing and cleaning of the electrodes, it is important to handle and keep them under clean condition until the use of them. In order to investigate the influence of keeping methods and terms on the vacuum breakdown characteristics of oxygen-free...
This paper reported the surface and volume resistivity of typical insulators under atmospheric condition and vacuum condition. The measured materials are some kinds of alumina ceramics which have different purity of Al2O3 component. It was confirmed that the surface resistivity for almost all of the insulator materials under vacuum condition was higher than that under atmospheric condition. In addition,...
A new method is proposed to analyze mode contents of high power electromagnetic waves that are propagating through corrugated waveguides in the electron cyclotron resonance heating (ECH) system for nuclear fusion devices. The method was applied to a 168 GHz transmission line of the ECH system in Large Helical Device (LHD) to evaluate the waveguide misalignment. Mode contents of the propagating wave...
We present a frequency tunable scheme for the gyrotron at millimeter/submillimeter regime. Unlike step-tunable type where oscillation jumps discretely in different transverse modes, this scheme allows a smooth tuning within a single transverse mode using its backward-wave component. The characteristics of backward-wave interaction will be shown. A proof of principle experiment was conducted with a...
On the basis of successful development of Gyrotron FU CW II, a similar gyrotron FU CW IIA is being developed for both 600 MHz and 300 MHz DNP-NMR experiments at the University of Warwick in UK. The frequencies of the gyrotron are 394.6 GHz at the second harmonic and 200 GHz at fundamental that correspond to frequencies 600 MHz and 200 GHz DNP-NMR spectroscopy. The output powers are around 30 W and...
Energy spectra of X-rays emitted from the surface of the FRP insulator were measured for 3 different positions and compared with those of the vacuum gap between electrodes. Near the anode, the X-ray spectrum was dominated by the monoenergetic electrons. Near the cathode, the spectrum peak shifted to low energy compared with that near the anode. This result showed that a large amount of low energy...
A sensitive NMR spectroscopy using a dynamic nuclear polarization (DNP) is an effective method to enhance the sensitivity of such versatile analytical technique. Its high performance realization requires a frequency tunable and powerful radiation source. A new gyrotron is developed with the aim of achieving the wide frequency tuning. The gyrotron FU CW IV operates at magnetic fields in the range of...
In rescue operation with a group of rescue robots, the robot has an ability to move around freely even if there are doors parting rooms. Since Great Hanshin Awaji earthquake, the rescue robot series named UMRS have been developed. This time the robot with a door opening system has been developed. This robot has the manipulator to locate the end effecter precisely to door knob position and the hand...
Polysilane 1 times 3 optical switch circuits were fabricated based on the thermo-optic effect. The waveguide insertion losses were less than -3.1 dB. Optical switch was performed with supplied power of 100 mW or less. Crosstalk attenuation was measured as less than 8.95 dB [1], [2], [3].
This paper examines technology licensing contracts and R&D investment in an industry with Cournot competition. We compare two licensing contracts, that is, fixed fee and royalty contracts. Specifically, we analyze a game in which in the first stage, a patent holding firm offers a licensing contract to its rival firm, the rival firm accepts or rejects the contract in the second stage, the two firms...
Recently, composite insulators have been increasingly employed mainly from the economic viewpoint. We have developed a new type outdoor termination with composite insulator, which can be installed horizontally on the steel tower, in order to reduce the construction cost. In this outdoor termination, SF6 gas is filled in the composite insulator and a cold shrinkable pre-molded rubber unit is applied...
The key issue in achieving a pedestrian navigation service is to grasp the spatial context of pedestrians, which is mainly characterized by the places of their interest. We have developed a pedestrian navigation system uNavi, based on our proposed infrastructure that is capable of associating information services to the places of human interest. This paper focuses on the implementation and deployment...
A power assist system for automobile slide doors that can provide comfortable operational feelings has been developed. The system incorporates a reference door model having preferable operational feelings. In order to follow virtual motion of the ideal door, both feedforward- and feedback-controllers are employed to drive a power assisting motor. Simulations and experiments have proved that the motion...
Reinforcement learning is a useful tool for complex control problems that cannot be modeled mathematically nor solved theoretically. Direct policy search(DPS) is an approach for reinforcement learning that represents a policy using some model and searches an optimal parameter directly by optimization techniques such as genetic algorithms(GA). Instance-based policy is a policy representation model...
Real-time reinforcement learning is difficult because number of episodes is too much to complete learning within limited time in practice. On the other hand, in spite of trial-and-error learning, animals can complete learning within limited time. Conventional framework cannot explain it. In this paper, we address the pursuit problem using optical information tau and information of direction that is...
Summary form only given. Recently, medium power, sub-THz gyrotrons were developed for application to DNP-NMR experiment for enhancing the sensitivity of NMR. In FIR FU, 394.6 GHz CW gyrotron FU CW II which is the second gyrotron of Gyrotron FU CW Series has been developed for DNP/NMR at 600 MHz under a collaboration with Institute of Protein Research, Osaka University. The output power and the frequency...
Random telegraph noise (RTN) in scaled FETs is one of the biggest concerns in the present and future LSIs. However, RTN in high-kappa gate dielectric FETs have not been fully studied yet. In this paper, we have studied RTN in high-kappa pFETs in comparison with that in SiO2 pFETs. It is found for the first time that the reduction of the RTN amplitude (DeltaId/Id) by the surface holes is smaller in...
Recently, a gyrotron in FIR FU with a 21 T pulse magnet achieved the breakthrough of 1 THz. In the gyrotron, a demountable gyrotron tube is installed on the center axis of 21 T pulse magnet. In the operation test, a high voltage pulse is applied to electron gun installed in the region of the additional coils for controlling the injection point of electron beam in the cavity region. When B in the cavity...
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