Random environments and automata

In this paper, we propose a machine like a stochastic automaton as the generalized random environment and show that every random environment discussed up to the present is a special case of this machine. The system consisting of this environment and an automaton is equivalent to an autonomous stochastic automaton. Moreover, we introduce some examples for this system.     

Practical method to determine the filter shape function used in the three-dimensional Fourier filtering method

The procedure to determine the appropriate filter shape function used in the three-dimensional Fourier filtering method (3D-FFM) is discussed from a practical point of view, so as to reduce the artificial contrast induced by the processing and to achieve a high signal-to-noise ratio. The effects of cutting off the high spatial frequency of the filter shape function and damping at low spatial frequency were investigated by using through-focus images of a gold (110) thin film. In addition, the effect of the width of the filtered area was discussed using through-focus images of a carbon nanotube. For reliable image processing, the filter shape function should be cut off beyond the information limit and attenuated with damping at low spatial frequency. Furthermore, the extraction area should include the distributed area of the relevant structural components appearing in the 3-D Fourier spectrum.     

High quality gate insulator film formation on SiC using by microwave-excited high-density plasma

High quality gate insulator film formation on 4H-SiC substrate is demonstrated. The insulator films were formed by the PECVD and radical oxynitridation using microwave-excited high-density plasma with NO gas at low temperature. The oxide fixed charge and the interface trap density can be dramatically reduced by NO gas radical oxynitridation after the oxide film formed by the PECVD compared with by direct oxynitridation on 4H-SiC. SIMS profiles show carbon profile in these fabricated gate insulator films. It is confirmed that the electrical property is improved as the amount of remaining carbon in the insulator film decreases.     

Development of a predictive prevention method for the midterm stability problem using only local information

There has recently been a consolidation of power system stability in connection with the extension and complication of power systems, although unstable behavior after a serious fault has been expanding from the transient area to the dynamic area. We therefore undertook the development of a dynamic stabilization method based exclusively on local information. In this paper we propose a new concept of real‐time modeling after a fault, using only local information. The control actions for stabilization of the power system are determined by behavioral prediction based on differential equations. The control actions of each generator are based on stability judgments at each local site. Case studies are presented to demonstrate the validity of the proposed method. © 2000 Scripta Technica, Electr Eng Jpn, 133(1): 43–52, 2000     

Protein Kinase C (Pkc)-δ Mediates Arginine-Induced Glucagon Secretion in Pancreatic α-Cells

The pathophysiology of type 2 diabetes involves insulin and glucagon. Protein kinase C (Pkc)-δ, a serine–threonine kinase, is ubiquitously expressed and involved in regulating cell death and proliferation. However, the role of Pkcδ in regulating glucagon secretion in pancreatic α-cells remains unclear. Therefore, this study aimed to elucidate the physiological role of Pkcδ in glucagon secretion from pancreatic α-cells. Glucagon secretions were investigated in Pkcδ-knockdown InR1G9 cells and pancreatic α-cell-specific Pkcδ-knockout (αPkcδKO) mice. Knockdown of Pkcδ in the glucagon-secreting cell line InR1G9 cells reduced glucagon secretion. The basic amino acid arginine enhances glucagon secretion via voltage-dependent calcium channels (VDCC). Furthermore, we showed that arginine increased Pkcδ phosphorylation at Thr⁵⁰⁵, which is critical for Pkcδ activation. Interestingly, the knockdown of Pkcδ in InR1G9 cells reduced arginine-induced glucagon secretion. Moreover, arginine-induced glucagon secretions were decreased in αPkcδKO mice and islets from αPkcδKO mice. Pkcδ is essential for arginine-induced glucagon secretion in pancreatic α-cells. Therefore, this study may contribute to the elucidation of the molecular mechanism of amino acid-induced glucagon secretion and the development of novel antidiabetic drugs targeting Pkcδ and glucagon.     

Recent activities in the field of radiation,accelerator, and beam technologies

Many of the outstanding researches and developments in the field of radiation, accelerator, and beam technology are published in scientific journals, including the Journal of Nuclear Science and Technology. Some topics from the latest activities in these fields are introduced.     

Hydrogen isotope dissolution and release behavior in Y-doped BaCeO3

Oxides having a perovskite structure are known to exhibit good proton conductivity in a high-temperature region, which makes them potential candidates in the tritium recovery and purification system of the electrochemical devices of fusion reactors such as hydrogen pumps, hydrogen sensors, and tritium monitoring systems. But the dissolution of hydrogen into the proton conductor and its release behavior is not well known yet. In this study, the dissolution and release behavior of hydrogen was investigated in BaCe_0.9Y_0.1O_3−α proton conductor by exposing deuterium gas (D₂) and heavy water vapor (D₂O) at 600 or 700°C for 5 h. The dissolved deuterium amount in the sample was measured using a temperature-programmed desorption analysis (TDS) method. The relationship between the amount of deuterium dissolved in the sample with the exposure pressure was also investigated. At room temperature (RT), the diffusivity of hydrogen (e.g., deuterium) was calculated from the change of the amount of residual hydrogen in the exposed sample due to the change of storage time. The Tritium Migration Analysis Program, Version 4 (TMAP4) simulation code was used to simulate and compare the experimental value of the obtained diffusivity. Although diffusivity at RT has not been reported in the past, the diffusivity is close to the extrapolation value of the literature data. From the comparison of this research results with literature, it may consider that the dominant diffusion mechanism does not change regardless of the temperature range.     

Formation speed of atomically flat surface on Si (1 0 0) in ultra-pure argon

The flattening speed of the low temperature atomically flattening technology is evaluated in order to apply atomically flat surface of (1 0 0) orientation on large-diameter silicon wafers to the LSI manufacturing. The atomically flatness of the whole surface of wafers with the diameter of 200 mm can be obtained after annealing at 800 °C or above. The process time required to obtain the atomically flatness for the whole wafer surface can be shortened by increasing the annealing temperature as well as by increasing the gas flow rate. With the off angle of 0.50° or below, it was found that only mono-atomic steps appear on the surfaces and the flattening speed is independent of the off angle. These indicate that the process speed is independent of the migration speed of Si atoms on the surface, but depends on the gas replacement efficiency near the Si surface in this technique.     

Dissolution behavior of (U,Zr)O2-based simulated fuel debris in nitric acid

To explore the possibility of dissolving fuel debris into nitric acid as a potential pre-treatment for waste treatment in which the U and Pu are removed from the inventory, dissolution tests of U_1?xZr_xO₂ and (U,Pu)_1?xZr_xO₂ were carried out in 6 M HNO₃ at 353 K. At the end of the dissolution test (after 4 h), the ratio of dissolved uranium decreased with an increase in the Zr contents, x. While the dissolution of U-rich samples was congruent, a preferential leaching of U was observed with Zr-rich samples. Taking into account these different dissolution phenomena, the dissolution rate analysis was carried out using surface-area model to calculate the instantaneous dissolution rate (IDR). The IDR decreased from 10^?5 down to 10^?10 mol cm^?2 min^?1 as x increased from 0 to 0.95. From these findings, dissolution with HNO₃ is expected to be only applicable in U-rich part of fuel debris (x < 0.3) if the dissolution in 6 M HNO₃ at 353 K is assumed. Application of complexing acids, such as mixture of HNO₃ and HF, should be considered to increase the dissolution rate of the Zr-rich part.     

Evaluation of enhanced conduction-corrected modified effective temperature ETFe as the outdoor thermal environment evaluation index

The purpose of this paper is made to clarify that the relationship between the human physiological and psychological responses and the enhanced conduction-corrected modified effective temperature ETFe as the outdoor thermal environment evaluation index upon the human body. Environmental factors and human physiological and psychological responses were measured. It was made clear that the variables by which summer outdoor environmental factors influence the thermal sensation vote are heat conduction, humidity and short-wave solar radiation. The variables that affect the thermal comfort vote are air velocity, heat conduction and humidity. ETFe, into which the environmental factors that are the variables for human response are incorporated, showed good correspondence with the thermal sensation vote. Similarly, ETFe has a good correspondence with thermal comfort vote. The usage of ETFe as a thermal environment evaluation index for summer outdoor spaces is valid. The threshold for the human body with regards to thermal environment stimuli in an outdoor space is higher than the thermal environment stimuli in a summer indoor space.