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Ion beam sputter cleaning, electrode surface heating by an infrared-ray, and an X-ray Photoelectron Spectroscopy (XPS) system were equipped in conjunction with a vacuum breakdown measurement apparatus (in situ experiment system). This system enables to carry out surface treatments, surface analysis and breakdown characteristics measurements without exposure of sample electrodes to air. It was confirmed...
We report on the novel, single photon counting, large area X-Ray camera called HyPix-3000 for in-house XRD. Its active area is 77.5 mm × 38.5 mm (approx. 3000 mm2) and it consists of 298,375 square-shaped pixels of the 100 µm pitch, each of which contains charge sensitive amplifier, shaper and two discriminators followed by two independent 16-bit long counters. It can operate in ultra-high dynamic...
Alumina ceramic is widely used for an insulator of vacuum interrupter. Occurrences of surface flashover along the insulator in vacuum have been a major obstacle to apply the vacuum interrupter for the higher rated voltage class, more than 100kV or further higher voltage. Therefore a superior alumina having high surface flashover voltage performance is required. Such a vacuum flashover occurrence is...
Based on the experimental data of the contraction ratio of fibroblast-collagen gels with different initial collagen concentrations and cell numbers, we analyzed the traction force exerted by individual cells through a novel elementary structural model. We postulate that the mechanical mechanism of the gel contraction is mainly because that populated cells apply traction force to some of the surrounding...
In this report an optical amplification with Bi doped silica fiber (BDF) fabricated by the Vapor Axial Deposition (VAD) method is presented. Bi concentration is measured as 0.07–1 mol%. The measured amplified gain was 6 dB with input low laser power at 1.3 µm using a double cladding BDF of 2 m.
Guiding mechanism of tube-leaky fibers composed only of a dielectric thin wall is explained by ray-optic method. The tube-leaky fiber supported by microstructured glass is fabricated and the loss at 2.94-μm wavelength was 0.87dB/m.
We clarified the relationship between the extinction ratio of upstream burst signals and Q factor of received signals to evaluate the impact of beat noise caused by residual noise interferences.
This paper presents magnetic levitation test results of a bearingless motor (BELM) based on d-q axis current control. The BELM based on d-q current control has been proposed by the authors. The stator winding arrangement and the control method have been conducted in detail. The rotational torque and the suspension force can be controlled by only one kind of stator winding. Hence, the winding arrangement...
Alumina ceramics is widely used as an insulating material for high voltage devices, because of low outgassing, hardness, low dielectric loss and high bulk breakdown voltage. However, there is serious problem to solve that the flashover voltage along the surface in vacuum is lower than that of a vacuum gap at the same length between electrodes. Many intensive researches have been carried out to improve...
Three Mega-Watt 77GHz gyrotrons were developed for an ECRH system in LHD. Their operation could be highly optimized by means of two-step rise of an anode voltage. Output power of 1.78MW with 37.9% efficiency were obtained in the 3rd gyrotron. The system improvement has been promoted including the development of a mmw-beam position and profile monitor.
This paper presents a radial position control method of bearingless motor (BELM) based on d-q axis current control and an integrated winding arrangement. The BELM performs the functions of motor as well as magnetic bearing. Rotor is suspended with non-contact by suspension force. In a conventional BELM, there are two kinds of stator windings such as motor and suspension windings. The motor winding...
The concept of design-manufacturing collaboration for nano-lithography era has been clarified. The novel design-manufacturing system that the manufacturing tolerance reflecting design intention properly can be allocated to the layout has been proposed. According to the system, one can assign the “weak portion” explicitly on the layout, and can control the process for reducing the burden of manufacturing...
As the operating frequency of LSI becomes higher and the power supply voltage becomes lower, the on-chip power supply variation has become a dominant factor which influences the signal delay of the circuits. The static timing analysis (STA) considering on-chip power supply variations (IR-drop) is therefore one of the most crucial issues in the LSI designs nowadays. We propose an efficient STA method...
The use of virtualization technology has been increasing in the IT industry to consolidate servers and reduce power consumption significantly. As a virtualization platform, a large-scale blade server is suitable because it can hold a dozen blades in a chassis with well managed configuration, enabling easy provisioning. To realize an energy-efficient blade server, the network component must deliver...
Accidents between battery-operated vehicles and pedestrians are expected to increase as electric vehicles (EV) or plug-in hybrid vehicles (PHV) are widely used in near future because of small ambient noise of EV/PHV. To prevent such accidents, a portable alert system for pedestrians to detect approaching vehicle is proposed in this paper. The alert system exploits ultra-wideband impulse radio (UWB-IR)...
The simulation results of the timing properties of a plastic scintillator are reported, when it is read by the WLS fiber. For the sake of completeness, we are beforehand with a simplified formula describing the light propagation in a fiber, and thereafter present the simulation results as the distributions for t1-t0 as well as t1+t2 to see the time resolution with t1 and t2 the times appeared at both...
The light yield (LY) of a wavelength shifter (WLS) fiber embedded in a plastic scintillator plate was studied by the MC simulation using the Mathematica package to find its optimum length and fiber density in the shashlik mode. It was identified whether or not the light absorbed in a fiber has been once reflected at any surface. The partial LY with reflections at upper and lower surfaces as well as...
In LHD, an ECH system for fusion-relevant plasma heating has been greatly progressed with the development of megawatt gyrotrons. Net power of 3.7 MW could be injected into LHD. For stable operation, a new position and profile monitor of the mmw-beams in evacuated transmission lines is developed.
This research investigates steady behaviors of a rotor at the resonance in a high-Tc superconducting bearing system. Such a low-damping multi-degree-of-freedom system, subjected to nonlinear force, can show complex dynamical behaviors. Our numerical and experimental results show that, in a system of a high-Tc superconducting bearing, subharmonic resonance and internal resonance with subharmonic resonance...
In this paper, we investigated the vacuum breakdown characteristics for some kinds of Ti electrodes which have different surface conditions. We focus on the influence of machining by the use of different tool bit, such as a cemented carbide tool bit and a cubic Boron Nitride (cBN) tool bit when the electrodes are manufactured with a lathing machine. Moreover we investigated the influence of the chemical...
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