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Sub-seafloor exploration is an important area of biological and geological research, and often requires samples of seafloor mud to be recovered. The minerals and marine sediments trapped in this mud are also potentially valuable resources. However, seabed exploration has been limited by the complexity and cost of the traditional equipment used. Wide area exploration can be made possible by deploying...
Wind is fundamental in many atmospheric phenomena. Global wind profile observation is important to improve numerical weather prediction (NWP) and various meteorological studies. Wind profile observations are measured mainly by radiosonde networks. Most of the weather stations are on land, while weather stations on oceans and remote land areas are sparsely distributed. The current global wind observing...
We have developed an excavation robot for lunar-subsurface exploration. This robot moves using a mechanism based on the peristaltic crawling of earthworms, which can move stably. In our previous study, we demonstrated that the robot can excavate down to 938 mm using this technique. However, it can only excavate in a straight configuration. If it can excavate while curving, its exploration range would...
Standard lithographic free wet etching process applied to thin (100 µm) p-type 156*156mm2 Czochralski (CZ) silicon to generate random micro pyramids with variable heights from 2 to 5 µm, which leads to reduce the surface reflection upto 10% by scattering. The present study mainly focus on to optimize etching recipe for maskless damage free neutral beam etching (NBE) to drill low aspect ratio nano...
We have been developing an excavation robot for lunar subsurface investigations. The robot locomotion is based on the peristaltic crawling of an earthworm, which enables stable movement. The robot comprises three units: propulsion, excavation, and discharging units. In our previous research, we demonstrated that the propulsion and excavation units can excavate down to 650 mm without the discharging...
The test operation were started from this January. During this operation some debugings of the software program and hardware circuit were carried out and the construction of this system was successifully completed by this April. We took much cares of the electrical isolation between equipments. Namely, we used the optical fiber cables to extend the serial highways. And in a power supply interface...
The Associative Memory (AM) system of the Fast TracKer (FTK) processor has been designed to perform pattern matching using as input the data from the silicon tracker in the ATLAS experiment. The AM is the primary component of the FTK system and is designed using ASIC technology (the AM chip) to execute pattern matching with a high degree of parallelism. The FTK system finds track candidates at low...
Half-metallic nature has been experimentally reported for some Cobalt (Co)-based full Heusler alloys, such as Co2MnSi [1], Co2(Fe-Mn)Si [2], Co2Fe(Al-Si) [3]. As has been reported in references [2, 3], it is effective to tune the material composition using a “4th element” for maximizing the spin polarization of the conduction electron. At the same time, such a 4th element sometimes increases the exchange...
We developed nearly-independent electrical "signature parameters" for surface pitting, hot electron damage, and electron trapping in GaN HEMT RF power devices. We then used the surface pitting signature parameter to find the rate of this degradation mechanism, without influence from the other mechanisms, occurring concurrently. This is important so the extracted thermal activation energy...
This paper presents a successful automatic voltage regulation of high-efficiency interior permanent-magnet (IPM) synchronous generators for pico-hydro power generation system. A 1-kW 4-pole V-type IPM generator with low voltage regulation is used for laboratory test in stand-alone hydro energy conversion system. It has been found from experimental results that the constant output voltage is supplied...
This paper presents the optimal rotor configuration and phase angle of the applied voltage for singlephase line-start high efficiency interior permanent magnet motors with start-up and synchronization capabilities under full-load torque. The rotor configuration with the excellent start-up and synchronization capability has been obtained from the simulation results using the finite element method....
This paper presents a successful design of a high-efficiency interior permanent-magnet generator which keeps terminal voltage constant from no load to rated load under a constant speed. This means the generator does not need the voltage control due to the voltage drop associated with the increase in load. Time-stepping finite-element analysis has been used to successfully predict the electromotive...
As an effective application of Neutral Beam Etching (NBE) to MEMS, we here propose a combined approach with conventional plasma process and NBE: removal of plasma-induced damage by NBE. If it is possible, we can obtain a damage-free surface for MEMS devices without a high-temperature annealing process. In order to evaluate the effect of this combined approach quantitatively; we focused on the resonance...
We have developed an exclusive planetary subsurface explorer robot with propulsion and excavation units. In this paper, we first explain the concept of our underground explorer robot. Next we develop an excavation unit with a tapered earth auger and a propulsion unit with dual pantograph. Several experiments are performed to demonstrate these features. Finally, we develop a subsurface explorer robot...
Lunar or planetary exploration missions including landers and rovers have been earnestly under study in Japan. One of the main missions for lunar robotics exploration is to demonstrate the technologies for lunar or planetary surface exploration, which will cover landing technology and surface exploration rover technology. Lunar geologic survey will be also performed for utilization and scientific...
In this paper we detailed a new three-dimensional Subgridding or Multigrid-FDTD method based on our recently proposed method in two-dimensions. First a 3D spatial subgridding method based on Monk's two-dimensional method is described. Then by using conservation principle we showed the spatial subgridding method is stable, as well as the temporal subgridding method used. Finally, by separating the...
We propose an algorithm for extracting the image of an object from the reconstructed image in the in-line digital holography using two holograms reported by Y. Zhang. In the proposed algorithm the non-diffraction wave can be analytically calculated by using the intensity of the reference wave and be removed from the reconstructed image. We confirmed the validity of the proposed algorithm by numerical...
We discuss the dynamical simulation model of the thermal environment for automobile passenger compartments which is useful for the development of automobile air-conditioning systems. In our previous research, we proposed the model of this type considering the accuracy and the amount of computation, however, proposed model was insufficient to simulate the effect of thermal radiation and insolation...
This paper presents a novel single-phase reluctance generator with low-cost ferrite magnets between adjacent stator teeth. The stator has both 4-pole field and 8-pole armature windings. The armature windings are connected to the input terminals of a single-phase full-bridge rectifier circuit as AC power source. The DC output terminals are connected to the field windings to increase the excited flux...
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