Pixel‐Structured Scintillator with Polymeric Microstructures for X‐Ray Image Sensors

We introduce a pixel‐structured scintillator realized on a flexible polymeric substrate and demonstrate its feasibility as an X‐ray converter when it is coupled to photosensitive elements. The sample was prepared by filling Gd₂O₂S:Tb scintillation material into a square‐pore‐shape cavity array fabricated with polyethylene. For comparison, a sample with the conventional continuous geometry was also prepared. Although the pixelated geometry showed X‐ray sensitivity of about 58% compared with the conventional geometry, the resolving power was improved by about 70% above a spatial frequency of 3 mm^?1. The spatial frequency at 10% of the modulation‐transfer function was about 6 mm^?1.     

Interconnection Technology Based on InSn Solder for Flexible Display Applications

A novel interconnection technology based on a 52InSn solder was developed for flexible display applications. The display industry is currently trying to develop a flexible display, and one of the crucial technologies for the implementation of a flexible display is to reduce the bonding process temperature to less than 150°C. InSn solder interconnection technology is proposed herein to reduce the electrical contact resistance and concurrently achieve a process temperature of less than 150°C. A solder bump maker (SBM) and fluxing underfill were developed for these purposes. SBM is a novel bumping material, and it is a mixture of a resin system and InSn solder powder. A maskless screen printing process was also developed using an SBM to reduce the cost of the bumping process. Fluxing underfill plays the role of a flux and an underfill concurrently to simplify the bonding process compared to a conventional flip‐chip bonding using a capillary underfill material. Using an SBM and fluxing underfill, a 20 μm pitch InSn solder SoP array on a glass substrate was successfully formed using a maskless screen printing process, and two glass substrates were bonded at 130°C.     

CMOS digital duty cycle correction circuit for multi-phase clock

A digital duty cycle correction circuit with a fixed-delay rising-edge output is proposed for use in applications with the multi-phase clock and the standby mode. Two integrators are used in the duty cycle detector to eliminate the effect of reference voltage variations. The output duty cycle is adjusted to 50/spl plusmn/0.25% throughout the input duty cycle range from 20% to 80% at the frequency of 1.25 GHz. 0.18 /spl mu/m CMOS technology is used in this work.     

Modular Layer‐by‐Layer Assembly of Polyelectrolytes,Nanoparticles, and Molecular Catalysts into Solar‐to‐Chemical Energy Conversion Devices

The design and fabrication of solar‐to‐chemical energy conversion devices are enabled through interweaving multiple components with various morphologies and unique functions using a versatile layer‐by‐layer assembly method. Cationic and anionic polyelectrolytes are used as an electrostatic adhesive to assemble the following functional materials: plasmonic Ag nanoparticles for improved light harvesting, upconversion nanoparticles for utilization of near‐infrared light, and polyoxometalate water oxidation catalysts for enhanced catalytic activity. Polyelectrolytes also have an additional function of passivating the surface recombination centers of the underlying photoelectrode. These functional components are precisely assembled on a model photoanode (e.g., Fe₂O₃ and BiVO₄) in a desired order and various combinations without degradation of their intrinsic properties. As a result, the performance of water oxidation photoanodes is synergistically enhanced. This study can enable the design and fabrication of novel solar‐to‐chemical energy conversion devices.     

Functionalization of Tailored Porous Carbon Monolith for Decontamination of Radioactive Substances

As the control over radioactive species becomes critical for the contemporary human life, the development of functional materials for decontamination of radioactive substances has also become important. In this work, a three-dimensional (3D) porous carbon monolith functionalized with Prussian blue particles was prepared through removal of colloidal silica particles from exfoliated graphene/silica composite precursors. The colloidal silica particles with a narrow size distribution were used to act a role of hard template and provide a sufficient surface area that could accommodate potentially hazardous radioactive substances by adsorption. The unique surface and pore structure of the functionalized porous carbon monolith was examined using electron microscopy and energy-dispersive X-ray analysis (EDS). The effective incorporation of PB nanoparticles was confirmed using diverse instrumentations such as X-ray diffraction (XRD), Fourier-transform infrared (FT-IR), and X-ray photoelectron spectroscopy (XPS). A nitrogen adsorption/desorption study showed that surface area and pore volume increased significantly compared with the starting precursor. Adsorption tests were performed with ¹³³Cs ions to examine adsorption isotherms using both Langmuir and Freundlich isotherms. In addition, adsorption kinetics were also investigated and parameters were calculated. The functionalized porous carbon monolith showed a relatively higher adsorption capacity than that of pristine porous carbon monolith and the bulk PB to most radioactive ions such as ¹³³Cs, ⁸⁵Rb, ¹³⁸Ba, ⁸⁸Sr, ¹⁴⁰Ce, and ²⁰⁵Tl. This material can be used for decontamination in expanded application fields.     

Who will cross the border? – The transition of political discussion into the newly emerged venues

This study explores the political implications of new communication technologies with a focus on their role as political discussion venues. Assuming that new technologies could expand the sphere for political discourse, we investigate the transition of citizens’ face-to-face political discussion into the computer-mediated online context. With analyses of a representative sample of US adults, this study explicates the link between the traditional and newly emerged discussion venues online. Our results reveal that significant differences in the transition pattern arise from variances in citizens’ political interest and age. In addition, in an attempt to reconcile the two seemingly conflicting hypotheses, we examine the role of political interest and age in the transition process within one integrated theoretical framework. Our findings highlight the conditions under which the democratic potential of the new venues becomes magnified, and draws attention to the importance of examining the dynamics underlying the transition of discussion venues.     

A simple method to prepare indium oxide nanoparticles: Structural,microstructural and magnetic properties

Indium oxide nanoparticles of ～12 nm were synthesized by a simple chemical route using indium(III) nitrate. Nanoparticles are formed after calcining the dried precursor in air at 400 °C for 10 h. TEM analysis showed that the morphology and size of the In₂O₃ samples were affected by ultrasonication. FTIR and Raman studies reveal that the nanoparticles are single-phase cubic structure of In₂O₃. NEXAFS study was used to quantify the Indium and oxygen valence state. Magnetic behavior of indium oxide nanoparticles was found to be diamagnetic. UV spectra show a weak band at ～308 nm corresponds to optical band gap energy of 4.03 eV.     

pH-sensitive photocatalytic activities of TiO2/poly(vinyl alcohol)/poly(acrylic acid) composite hydrogels

The pH-sensitive photocatalytic system was prepared by embedding TiO₂ into poly(vinyl alcohol)/poly(acrylic acid) hydrogel. Two different type TiO₂/hydrogel composites, such as matrix and nanofiber, were prepared to investigate the morphological effects on the photocatalytic activity. TiO₂ was distributed uniformly in the composite hydrogel and kept the original anatase structure without any structural change. The photocatalytic activity of TiO₂ was evaluated based on the efficiency of photobleaching of dye. The photobleaching of dye was improved greatly as the pH was changed into basic condition and the larger surface area of hydrogel was available for TiO₂ by using nanofiber supports.     

Codes based on BCK-algebras

The notion of a BCK-valued function on a set is introduced, and related properties are investigated. Codes generated by BCK-valued functions are established.     

Development of an apparatus for removing magnetic sludge by permanent magnets setup in the condenser of the power plant

In this paper, permanent magnets are used to remove magnetic sludge in the condenser of the power plant. To obtain the flow characteristics and magnetic information that are needed for determining a proper design of the magnetic sludge removal apparatus, we performed numerical simulations through the use of two commercial codes, ANSYS Workbench-Emag and CFX. We also performed experiments on various kinds and sizes of magnets to obtain the magnetic information through a gauss meter. By analyzing the results of simulations and experiments, the minimum magnetic force that is able to remove the any size of the magnetic sludge in the condenser was calculated, and the design of the removal apparatus was confirmed. We made the test model which was confirmed by the simulations and experiments for the tests of efficiency of the removal apparatus. After testing, the test results were compared with those of numerical simulations and have good agreements.