Shigeyuki Minami

The global distribution of pure anorthosite on the Moon

It has been thought that the lunar highland crust was formed by the crystallization and floatation of plagioclase from a global magma ocean, although the actual generation mechanisms are still debated. The composition of the lunar highland crust is therefore important for understanding the formation of such a magma ocean and the subsequent evolution of the Moon. The Multiband Imager on the Selenological and Engineering Explorer (SELENE) has a high spatial resolution of optimized spectral coverage, which should allow a clear view of the composition of the lunar crust. Here we report the global distribution of rocks of high plagioclase abundance (approaching 100 vol.%), using an unambiguous plagioclase absorption band recorded by the SELENE Multiband Imager. If the upper crust indeed consists of nearly 100 vol.% plagioclase, this is significantly higher than previous estimates of 82–92 vol.% (refs 2, 6, 7), providing a valuable constraint on models of lunar magma ocean evolution.

Laboratory evidence of earthward electric field in the magnetotail current sheet

In a laboratory simulation experiment of the earths magnetosphere, an evidence of the existence of an earthward electric field is shown in the equatorial current sheet. The earthward electric field may be generated as a result of Hall electric field generation in the current sheet. A simple theoretical model for the existence of an earthward electric field is presented. The ions in the current sheet are accelerated by this earthward electric field, which then penetrate into the near earth dipole magnetic field. At the end of the current sheet near the earth, these ions are accumulated due to the difference of the inertia between ions and electrons. The polarization of charges reverses the electric field from earthward to tailward at this region. The experimental results have shown two directional electric fields along x-axis in the current sheet. The earthward direction of the electric field is due to the dawn-dusk current sheet carried by electrons. These experimental results prove the theoretical prediction. A discussion of the application of this result to the real magnetotail physics is also presented.

Comparison between two piezoelectric lead-zirconate-titanate detectors bombarded with high-energy xenon beam

The characteristics of piezoelectric lead–zirconate–titanate (PZT) detectors were studied by directly irradiating them with a 400 MeV/n Xe beam. The sensitivity of a multilayered detector was discussed in comparison with that of a monolayered detector. It was found that the sensitivity of the detectors depended on their structure.

An analytical method of EV velocity profile determination from the power consumption of electric vehicles

Concerning a carpsilas performance, acceleration and deceleration are the most important features in performance assessments. Fuel consumption has been a key issue in the performance of cars in recent years. Electric vehicles (EV) with high energy-efficiency have been developed for such a reason. However, problems related to the running distance per charging, the charging time, and so on have remained because of the smaller battery energy stored in. Under these circumstances, it is more important to analyze the running state of EV. To obtain longer running distance and good mileage, a theoretical equation to determine the EV performance to the input electric power is deduced. As to an EV, deriving the accelerated velocity, a, from a situation when electric input power, P, is given to an EV, driving at a velocity, v, is extremely important in order to find out the acceleration performance of a car. This paper analytically describes a method to obtain the performance of the EV from equations between the measured acceleration, a, and the input or regenerated electric power, P. It is shown that this method can demonstrate possibilities to predict the performance of electric vehicles using stored electric energy and the driving root.

EV range extender: Better mileage than plug-in hybrid?

This paper shows that EV range-extender (RXT) will provide better mileage than the plug-in hybrid (PHEV) when a model usage of vehicle is applied. The model is assumed to be: 30 km (6 days a week), 100 km (1 day a week). A RXT system was made for this evaluation using a pure EV and an electric generator on a trail. Japan 10-15 mode is used for the calculation. The result shows that 35.4 kWh/weeks is obtained for RXT, while 36.5 kWh/week for PHEV. This would be the first evaluation of RXT based on the fuel economy.

Measurement of temperature after hypervelocity collision of microparticles in the range from 10 to 40 km/s

The temperature recorded immediately after hypervelocity collision of microparticles comprising iron and nickel with a silver-coated piezoelectric plate was analyzed using photomultipliers of different spectral response characteristics. The conversion rate between the velocity and temperature is estimated to be ∼900 K/km∕s in the velocity range of 10–40 km/s. This rate is greater than that reported earlier.

Ionospheric stimulation by high power radio waves

Abstract We have performed an experiment to artificially stimulate the ionosphere using higher power radio waves at the HIPAS (High Power Auroral Stimulation) facility in Alaska. A radio transmission of 2.85 MHz was made at 80 MW (ERP). Diagnostics were made at the other site located 35 km from the transmission site. The results of cross-correlating the excited HF wave and observed with an 8 channel, 30 MHz scanning cosmic radio noise absorption records revealed the excited height of 90 km. Also atmospheric pressure waves observed on the ground show evident propagation of pressure waves which are generated in the ionosphere by the high-power HF wave. The results determine the excitation height of 90 km in the ionosphere and show evidence of the pressure wave coupling between the ionosphere and the lower atmosphere for periods of 10 min.

Performance of a newly developed plug-in hybrid boat

We have produced a new-type of plug-in hybrid boat. This boat has excellent environment characteristics running by electricity, while having the ability of long-distance cruising and long distance reliability because of the diesel engine. The excellent performances of this plug-in hybrid boat system are described.

Position Sensitive Element for Hypervelocity Microparticles Using a Piezoelectric Plate

The propagation of transverse waves generated acoustically in a piezoelectric element by colliding it with hypervelocity microparticles was studied. The propagation times were measured by a set of multiple electrodes on the surface of the element. The coordinates that the particles struck were determined by combining the propagation times and the velocity of the waves. By using the position-sensitive element, significant deviations between the prior indicated and actually measured orbits were observed. The potential of the present element as part of a steering system is discussed.

Effects of the local interstellar medium magnetic field on the structure of the heliosphere: A laboratory simulation

The ‘heliopause’ is the hypothesized boundary separating the outflowing solar wind from the interstellar medium. The outer heliosphere itself is a problem of topical interest because several spacecraft are presently cruising towards the terminal shock of the heliosphere. While there have been theoretical and computer simulation studies of this boundary, there has so far been no laboratory simulation. We have now performed such a simulation, and the results are presented here. The results indicate the possible existence of such a boundary as being highly axiasymmetrical in the case of the low Alfvenic Mach number of the local interstellar medium.