We demonstrate the tungsten disulfide (WS2) thin film catalysts prepared by the sulfurization of vacuum deposited WO3 thin films for efficient hydrogen production with over 90% Faradaic efficiency. The 23-nm-thick WS2 thin film catalyst heterojunction with p-type silicon photocathode could exhibit a photocurrent density of 8.3 mA/cm2 at 0 V versus a reversible hydrogen electrode (RHE), a low onset potential of 0.2 V versus RHE when photocurrent density reaches −1 mA/cm2 and long-term stability over 10 h. The enhanced catalytic activities of WS2/p-Si photocathodes compared with the bare p-Si photocathode originate from a number of edge sites in the synthesized polycrystalline thin films, which could act as hydrogen evolution catalyst.

Pb is released from bone stores during pregnancy, which constitutes a period of increased bone resorption. A high Na intake has been found to be negatively associated with Ca and adversely associated with bone metabolism. It is possible that a high Na intake during pregnancy increases the blood Pb concentration; however, no previous study has reported on the relationship between Na intake and blood Pb concentration. We thus have investigated this relationship between Na intake and blood Pb concentrations, and examined whether this relationship differs with Ca intake in pregnant Korean women. Blood Pb concentrations were analysed in 1090 pregnant women at mid-pregnancy. Dietary intakes during mid-pregnancy were estimated by a 24 h recall method covering the use of dietary supplements. Blood Pb concentrations in whole-blood samples were analysed using graphite furnace atomic absorption spectrophotometry. Multiple regression analysis performed after adjustment for covariates revealed that maternal Na intake was positively associated with blood Pb concentration during pregnancy, but only when Ca intake was below the estimated average requirement for pregnant Korean women (P= 0·001). The findings of the present study suggest that blood Pb concentration during pregnancy could be minimised by dietary recommendations that include decreased Na and increased Ca intakes.

The effect of wet chemical treatment on the magnetic tunneling junction (MTJ) was examined. The tunneling magneto-resistance (TMR) increased and the resistance of anti-parallel state and parallel state decreased when a wet cleaning treatment was carried out after a reactive ion etching process. Furthermore, the exfoliation between the capping layer and Inter layer Dielectric (ILD) was prevented. Presumably, these were due to the elimination of the damaged layer and the residues. This investigation showed that the wet treatment after the MTJ patterning using RIE process could improve the MTJ properties without degradation of Hc, such as TMR and Rlow.

The hydrophobicity of poly Si is reported to introduce different polishing behavior with careful control of post CMP cleaning process. The purpose of this study was to investigate the effect of poly Si wettability on its CMP behavior. The adhesion force of polymeric particle on the poly Si wafer surfaces was measured in the KOH solution (pH 11) as a function of solution A concentration. Adhesion force decreased and saturated as a function of concentration of solution A. The change of surface wettability affects not only the polishing rates but also the level of contamination on wafer because the interactions between particles and substrates are dependent on the wettability of the surface. Also, hydrophobic poly Si surfaces attracted much more pad particles with water marks than hydrophilic

The aim of this study was to investigate the usefulness of a three-dimensional (3D) reconstruction of computed tomography (CT) images in determining the anatomy and topographic relationship between various important structures. Using 40 ears from 20 patients with various otological diseases, a 3D reconstruction based on the image data from spiral high-resolution CT was performed by segmentation, volume-rendering and surface-rendering algorithms on a personal computer. The 3D display of the middle and inner ear structures was demonstrated in detail. Computer-assisted measurements, many of which could not be easily measured in vivo, of the reconstructed structures provided accurate anatomic details that improved the surgeon’s understanding of spatial relationships. A 3D reconstruction of temporal bone CT might be useful for education and increasing understanding of the anatomical structures of the temporal bone. However, it will be necessary to confirm the correlation between the 3D reconstructed images and histological sections through a validation study.

A geometric approach to Low Earth Orbiter (LEO) precision orbit determination (POD) based exclusively on triple-differenced GPS carrier phase observables is presented. The algorithm is fast and efficient because there is no ambiguity-resolution requirement, which is a complicated and time-consuming task for long-range kinematic GPS. However, the triple-difference kinematic LEO POD requires careful screening for cycle slips, as the orbit quality depends on the accuracy and the geometry of the observations. It is shown that the signal-to-noise-ratio (SNR) combined with residual screening offers a good approach to data cleaning. Data from a CHAMP (Challenging Minisatellite Payload, altitude ~450 km) mission are used to present the accuracy, speed and efficiency of the processing algorithms. The methods of data screening and the effects of geometry on the orbit quality are discussed and the final achievable accuracy including the limitations and benefits of this method are quantified. It is demonstrated that the triple-difference method offers short processing times and is currently capable of achieving a 3D RMS fit to the dynamic orbit of 15–30 cm and 1 mm/s to the velocity.

This study presents the effect of pad properties, such as elastic modulus and surface roughness, on planarity in a CMP process. A systematic method to measure planarization length, which represents the die-scale planarity in a quantitative manner, has been proposed. It has been shown that the planarization length is highly dependent on the bulk modulus of the pad. The effect of elastic modulus and roughness of the pad on dishing amount, which represents the feature-scale planarity, has been shown. Dishing amount is determined by the elastic modulus of the superficial layer of the pad, which is typically tens of microns thick, rather than by the bulk elastic modulus of the pad. A double layer pad model has been proposed based on the observed results, which can explain that the dishing amount is reduced by increasing elastic modulus of the pad superficial layer, or by decreasing the surface roughness of the pad.

Simulation of chemical-mechanical polishing is important because the chip-level planarity are difficult to control. The simulator has been developed for predicting and optimizing the thickness distribution after the STI and damascene CMP as well as ILD CMP using chip-level pattern density, elastic spring model and erosion model. In this study, the results of CMP simulation is shown to agree well with the measured data. The simulator can be used to optimize CMP process conditions and to generate design rules for filling dummy patterns which are used to improve the planarity and uniformity.

In order to investigate microstructural variation by 2-1-1 addition in partially melted Y–Ba–Cu–O, a specimen resulting from 2-1-1 added to 1-2-3 was heat-treated through the peritectic temperature. Microstructure was observed on the directionally solidified region near the interface of the two samples. The 2-1-1 addition results in a homogeneous microstructure where no remnant liquid phase is present. It reduced the 1-2-3 plate thickness, as well as suppressed the formation of microcracks due to the tetragonal-to-orthorhombic phase transition or the thermal contraction during cooling from the peritectic temperature. The formation of microcracks induced by the phase transition seems to be closely related to the process of oxygen diffusion into a sample. We discuss the formation of microcracks in terms of the oxygen diffusion along the plate boundaries and of the thickness of 1-2-3 plates. The decrease in the plate thickness and the fine dispersion of 2-1-1 particles contribute suppression of the formation of microcracks and their propagation.