Microdosimetry of neutron field for boron neutron capture therapy at Kyoto university reactor

Microdosimetric single event spectrum in a human body simulated by an acrylic phantom has been measured for the clinical BNCT field at the Kyoto University Reactor (KUR). The recoil particles resulting from the initial reaction and subsequent interactions, namely protons, electrons, alpha particles and carbon nuclei are identified in the microdosimetric spectrum. The relative contributions to the neutron dose from proton, alpha particles and carbon are estimated to be about 0.9, 0.07 and 0.3, respectively, four depths between 5 and 41 mm. We estimate that the dose averaged lineal energy, yD decreased with depth from 64 to 46 keV microm(-1). Relative biological effectiveness (RBE) of this neutron field using a response function for the microdosimetric spectrum was estimated to decrease from 3.6 to 2.9 with increasing depth.     

A Review of Broad-Band Fiber System Activity in Japan

In the future information society, various kinds of services will be required in offices, factories, homes, and communities. Fiber optic broad-band systems will play the most important role in the integrated services networks that will provide such services. This paper reviews field trials of fiber optic broad-band systems in Japan, focusing on subscriber loop system technology.     

SoI--gel modification of pH electrode glass membranes for sensing anions and metal ions

To obtain glass membrane electrodes selective for anions and metal ions, pH electrode glass membranes were modified by a sol-gel method using a quaternary ammonium salt and a bis(crown ether). A chloride ion-sensing glass membrane was designed, in which a pH electrode glass membrane was modified chemically by an alkoxysilyl quaternary ammonium chloride. X-ray photoelectron spectroscopy confirmed the chemical bonding of the quaternary ammonium moiety to the starting glass surface, which afforded the first example of glass-based "anion"-sensing membranes. A neutral carrier-type sodium ion-selective glass membrane was also fabricated which encapsulates a bis(12-crown-4) derivative in its sol-gel-derived surface. Both sol-gel-modified anion and metal ion-selective glass electrodes exhibited high sensitivity to their ion activity changes. The present sol-gel modification paves the way for designing glass-based ion sensors with tailor-made ion selectivities toward anions as well as cations.     

Crosstalk Countermeasures for High-Density Inductive-Coupling Channel Array

Inductive coupling among stacked chips in a package enables 1 Gb/s/channel data communications. Array arrangement of the channel increases data bandwidth, while signal may be degraded by crosstalk. In this paper, crosstalk is measured and analyzed, and crosstalk countermeasures are discussed. Received signal waveforms through the inductive coupling are measured by embedded voltage detectors on a test chip. Interference-to-signal ratio (ISR) has good agreement between the measurements and calculations. It is found that crosstalk is reduced negligibly at a certain distance. If the channels are arranged at intervals of this distance, ISR is minimized. A technique based on time interleaving is also proposed to further reduce crosstalk. A 3times17 channel array is implemented with the crosstalk countermeasures. The channel pitch is taken down to 50 mum. Inter-chip communication with data rate of 1 Gb/s/channel and bit error rate (BER) lower than 10^-9 is demonstrated     

Color displays and flexible displays using quick‐response liquid‐powder technology for electronic paper

Abstract— Color displays and flexible displays that use electronic liquid powder have been developed. Novel types of color displays using either a colored powder or a color filter are discussed. We have also developed a flexible display with low‐cost substrate films with a high‐throughput roll‐to‐roll manufacturing method. These technologies enable a QR‐LPD to be widely used as an electronic‐paper display.     

Evolution of cooperation in reputation system by group-based scheme

Reputation systems are very useful in large online communities in which users may frequently have the opportunity to interact with users with whom they have no prior experience. Recently, how to enhance the cooperative behaviors in the reputation system has become to one of the key open issues. Emerging schemes focused on developing efficient reward and punishment mechanisms or capturing the social or economic properties of participants. However, whether this kind of method can work widely or not has been hard to prove until now. Research in evolutionary game theory shows that group selection (or multilevel selection) can favor the cooperative behavior in the finite population. Furthermore, some recent works give fundamental conditions for the evolution of cooperation by group selection. In the paper, we extend the original group selection theory and propose a group-based scheme to enhance cooperation for online reputation systems. Related concepts are defined to capture the social structure and ties among participants in reputation system, e.g., group, assortativity, etc. Also, we use a Fermi distribution function to reflect the bounded rationality of participants and the existence of stochastic factors in evolutionary process. Extended simulations show that our scheme can enhance cooperation and improve the average performance of participants (e.g. payoff) in reputation system.     

Chemical Reactivity and Load Carrying Capacity of Lubricating Oils Containing Organic Phosphorus Compounds

The work described in this paper is a study of the high temperature corrosion reaction of iron in oils containing phosphorus compounds such as the phosphite, phosphate, thiosulphate, acid phosphate and acid phosphite, by using the hot-wire method. The neutral type esters show very little chemical reactivity towards iron in marked contrast to the very high reactivity of the acid type esters and thiophosphite. X-ray analysis revealed basic iron phosphate, 2FeFe₄(PO₄)(OH)₅, and iron sulfide as the main reaction products for the neutral type and acid type esters and thiophosphite, respectively. The surface polishing action, peculiarly attributed to phosphorus compounds, could not be confirmed in the present work. The results from X-ray analysis seem to support the iron phosphate lubrication mechanism of phosphorus type EP additives. Some considerations are given for the correlations between the chemical reactivity, load carrying capacity and anti-wear property of oils containing phosphorus compounds. As to the lubrication characteristics of chloride, sulfide, phosphide and phosphate films, some postulations are made.     

2 Gb/s 15 pJ/b/chip Inductive-Coupling Programmable Bus for NAND Flash Memory Stacking

An inductive-coupling programmable bus for NAND flash memory access in solid state drive (SSD) is presented. Compared to the conventional SSD, this wireless interface using relayed transmission reduces power consumption to 1/2, I/O circuit-layout area to 1/40, and achieves a data rate of 2 Gb/s in 0.18 ?m CMOS process. In addition, since this wireless interface enables one package to contain 64 chips, the number of packages is reduced to 1/8.