Seven-year temporal variation of Caesium-137 discharge inventory from the port of Fukushima Daiichi Nuclear Power Plant: continuous monthly estimation of Caesium-137 discharge in the period from April 2011 to June 2018

ABSTRACT

After direct discharges of highly contaminated water of the Fukushima Daiichi Nuclear Power Plant (1 F) from April to May 2011, Kanda suggested that relatively small amounts of run-off of radionuclides from the 1 F port into the Fukushima coastal region subsequently continued by his estimation method. However, the estimation period was limited to up to September 2012. Therefore, this paper estimatesthe discharge inventory up to June 2018. In the missing period, the Japanese government and Tokyo Electric Power Company Holdings have continued efforts to stop the discharge, and consequently, the radionuclide concentration in seawater inside the 1 F port has gradually diminished. We show the monthly discharge inventory of ¹³⁷Cs up to June 2018 by two methods, i.e., Kanda method partially improved by the authors and a more sophisticated method using Voronoi tessellation reflecting the increase in the number of monitoring points inside the 1 F port. The results show that the former always yields overestimated results compared with the latter, but the ratio of the former to the latter is less than one order of magnitude. Using these results, we evaluate the impact of the discharge inventory from the 1 F port into the coastal area and radiation dose upon fish ingestion.     

High-performance composites from polyimide matrix resins that utilize a cross linking reaction of biphenylene end-caps with acetylene units in the main chain

Graphite-reinforced composites were prepared with oligomeric polyimides having biphenylene end-caps and acetylene linkages in the polymer chain. The oligomers were crosslinked by the reaction of the biphenylenes with the diphenyl acetylenes to form 9,10-diphenylphenanthrene units. The resulting composites had good mechanical properties. Thermal oxidative aging studies show that the unidirectional graphite fiber composites maintained good mechanical properties up to 1200 h at 316°C.     

Application of genetic algorithm to speed servo system and positioning system

This paper considers a genetic algorithm application to feedforward controllers of speed servo and positioning systems. The system consists of a conventional feedback controller and a feedforward controller. The parameters of the feedforward controller are regarded as the chromosome on a gene. The genetic algorithm is used to tune the parameters of the feedforward controller, the objective of which is to make the feedforward controller a dynamic inverse of the plant. The tracking error between the desired output and the actual output at every sampling period is used to calculate the fitness of one gene. The range of mutation is dependent on the magnitude of the tracking error, which ensures parameter convergence. The effect of fitness function and the width of mutation on tracking performances is investigated. The experimental results demonstrate the effectiveness of the proposed genetic algorithm in improving tracking performances.     

How map designers can represent their ideas in thematic maps

Problem analysis in designing thematic maps and user interfaces which assist map designers in incorporating their ideas into maps are presented. Problems in designing choropleth maps are analyzed from the map designers point of view. A graphical user interface, called “Histogram Interface”, is implemented as countermeasure for problems in designing choropleth maps. The user interface can assist map designers in representing their ideas and achieving the desired maps through the designing process. The user interface operations, which correspond to the map designer's ideas, are explained. The user interface effectiveness is confirmed by resulting map examples and the corresponding graphical patterns on the interface. A concept is proposed concerning the importance in any computer graphics field, which the designers should consider in determining how to incorporate their ideas into pictures.     

p60v-src causes tyrosine phosphorylation and inactivation of the N-cadherin-catenin cell adhesion system

Transformation of chick embryonic fibroblasts with Rous sarcoma virus strongly suppresses N-cadherin-mediated cell-cell adhesion, without inhibiting its expression. This suppression is correlated with tyrosine phosphorylation of N-cadherin and catenins, the cadherin-associated proteins, which are known to regulate cadherin function. Experiments with non-myristylation and temperature-sensitive mutants of RSV and with herbimycin A, a potent inhibitor of tyrosine kinases, suggest that both the suppression of cell adhesion and tyrosine phosphorylation of catenins are highly transformation-specific.     

Development of a high‐speed laser interferometer using an acousto‐optic deflector

An acousto‐optic laser deflector was used as a shutter for high‐speed imaging of laser interference fringes using an ordinary CCD camera. The exposure duration was set by the pulse width of the high‐frequency signal applied to the acousto‐optic deflector. Changes in laser interference fringes due to an impulse discharge in air were obtained at an exposure duration of 4 µs. By applying a sequence of high‐frequency signals with different frequency, the beam was deflected to four different angles at different times, allowing four interference images to be captured on a single video frame. This was used for time‐resolved imaging of the interference fringe pattern. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 148(2): 76–83, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20011     

Discrete‐Valued Model Predictive Control Using Sum‐of‐Absolute‐Values Optimization

In this paper, we propose a new design method of discrete‐valued model predictive control for continuous‐time linear time‐invariant systems based on sum‐of‐absolute‐values (SOAV) optimization. The finite‐horizon discrete‐valued control design is formulated as an SOAV optimal control, which is an expansion of L¹ optimal control. It is known that under the normality assumption, the SOAV optimal control exists and takes values in a fixed finite alphabet set if the initial state lies in a subset of the reachable set. In this paper, we analyze the existence and discreteness property for systems that do not necessarily satisfy the normality assumption. Then, we extend the finite‐horizon SOAV optimal control to infinite‐horizon model predictive control (MPC). We give sufficient conditions for the recursive feasibility and the stability of the MPC‐based feedback system in the presence of bounded noise. Simulation results show the effectiveness of the proposed method.     

A novel low‐power gate driver architecture for large 8 K 120 Hz liquid crystal display employing IGZO technology

A novel low‐power gate driver architecture was developed for large 8 K 120 Hz liquid crystal display panel. For this application, not only high‐speed driving but also low power consumption is required. We employed a high mobility In‐Ga‐Zn‐O, dual V_GL level driving method, and gate driver circuit driven by DC supply. The simulation results show that our proposals meet 8 K 120 Hz driving requirements. Also, we have fabricated a prototype panel and confirmed both high‐speed driving and low power consumption.     

Perspectives and Prospects on Transformer Architecture for Cross-Modal Tasks with Language and Vision

International Journal of Computer Vision - Transformer architectures have brought about fundamental changes to computational linguistic field, which had been dominated by recurrent neural networks...     

Evaluation and Statistical Analysis of Dielectric Permittivity of BaTiO3 Powders

A slurry method was used to determine the dielectric permittivity (ɛ_r) of BaTiO₃ powders with different characteristics, such as tetragonality ( c / a ratio), density, particle size, and specific surface area. The ɛ_r of powders highly depended on their characteristics. In order to extract the effect of each characteristic, a statistical analysis was carried out to represent the ɛ_r of powders with an empirical formula. A fairly good agreement was obtained between observed data and those estimated from the formula. The ɛ_r decreased with particle size because of the size effect of BaTiO₃ and high tetragonality and density was essential to obtain high ɛ_r of powders.