Efficient photocatalytic H2 production using visible‐light irradiation and (CuAg)xIn2xZn2(1 − 2x)S2 photocatalysts with tunable band gaps

The band structures of semiconductor photocatalysts fundamentally determine the photocatalytic activity and the H₂ production from the visible‐light‐driven water‐splitting reaction. We synthesize a suite of multicomponent sulfide photocatalysts, (CuAg)_xIn_2xZn_{2(1 ? 2x)}S₂ (0 ≤ x ≤ 0.5), with tunable band gaps and small crystallite sizes to produce H₂ using visible‐light irradiation. The band gap of the photocatalysts decreases from 3.47 eV to 1.51 eV with the increasing x value. The (CuAg)_0.15In_0.3Zn_1.4S₂ (x = 0.15) photocatalyst yielded the highest photocatalytic activity for H₂ production owing to the broad visible‐light absorption range and suitable conduction band potential. Under the optimized reaction conditions, the highest H₂ production rate is 230 µmol m^?2 h^?1 with a visible‐light irradiation of 2.7 × 10^?5 einstein cm^?2 s^?1, and the quantum yield reaches 12.8% at 420 ± 5 nm within 24 h. Furthermore, the photocatalytic H₂ production is shown to strongly depend on their band structures, which vary with the elemental ratios and could be analyzed by the Nernst relation. Copyright © 2014 John Wiley & Sons, Ltd.     

An Ecr-sputtered zno epitaxial film and its characteristics

Abstract

The properties of ZnO film deposited by an RF-magentron-mode Electron Cyclotron Resonance (ECR) sputtering system, which has added magnets to the outside of a cylindrical Zn metal target of the RF-mode ECR sputtering system reported previously^[1], are investigated. The ZnO film on the glass substrate deposited by this system was capable of driving a 1.3 GHz fundamental Rayleigh SAW for the first time. These films exhibit almost the same effective electromechanical coupling factors Keff as the theoretical Keff values calculated by finite element method (FEM).     

Surgical treatment for Scheie's syndrome (mucopolysaccharidosis type I-S): report of two cases

Scheie's syndrome (mucopolysaccharidosis type I-S) is a rare genetic lysosomal storage disease affecting mucopolysaccharide metabolism, and is known to include cardiovascular disease. Surgical treatment was carried out in 2 patients with Scheie's syndrome. Patient 1 was a 56-year-old man with triple-vessel coronary artery disease, who successfully underwent coronary artery bypass grafting. Patient 2 was a 52-year-old man with aortic and mitral valve stenosis, who successfully underwent combined aortic and mitral valve replacement. The literature on Scheie's syndrome associated with valvular and coronary artery disease is also reviewed.     

Dietary Mg and/or K restriction enhances paraquat toxicity in rats

Effect of mineral restriction was studied to clarify which mineral in the diet is most indispensable in preventing paraquat (PQ) toxicosis. ODS rats were chosen as the experimental animal owing to the inability to synthesize vitamin C similarly to humans. Rats were fed with either mineral-adequate or restricted diets dosed with 125 ppm PQ. The mineral-adequate diet was based on the American Institute of Nutrition-76, and the restricted diet was one-half the amounts. Measurements were made on the onset day of PQ toxicosis, body weight changes during the feeding experiment, and changes of two acute phase reactant proteins cysteine proteinase inhibitor and alpha1-proteinase inhibitor. The minerals tested were divided into three classes: I, largely needed, Ca, K, Na, and Mg; II, moderately needed, Mn, Fe, Zn, and Cu; and III, minutely needed, Cr and Se, respectively. Rats fed with a Mg-restricted diet showed a severe toxicosis but those with a K-restricted diet, a mild toxicosis. No appreciable effect was observed by restriction of other minerals. A synergistic effect was observed in the restriction of Mg and K.     

Deposition and piezoelectric characteristics of ZnO films by usingan ECR sputtering system

Piezoelectric properties of ZnO films, were investigated by using an Electron Cyclotron Resonance (ECR) sputtering system. It was confirmed that this system was capable of depositing a ZnO film with a large specific resistance, and good c-axis orientation on an interdigital transducer (IDT)/glass substrate at a low temperature (less than 200°C) and in a low gas pressure (~10^-4 torr). Furthermore, these ZnO films exhibited excellent SAW characteristics (insertion losses) and effective electromechanical coupling factors (k _eff) compared with ZnO films deposited by a conventional RF magnetron sputtering system. Further, this ECR sputtering system was capable of depositing a ZnO film, without heating the substrate, that was capable of propagating a Rayleigh SAW at 700 MHz for the first time     

The leech excitatory peptide, a member of the GGNG peptide family: isolation and comparison with the earthworm GGNG peptides

A member of the GGNG peptide family was isolated from Hirudo nipponia (leech). GGNG peptides had only been isolated previously from earthworms. The C-terminus structure of the leech peptide, LEP (leech excitatory peptide), was -Gly-Gly-Asn-amide, while that of the earthworm peptides, EEP (earthworm excitatory peptide), was -Gly-Gly-Asn-Gly. LEP exerted 1000-fold more potent activities on leech gut than did EEP-2. On the other hand, EEP-2 was 1000-fold more potent than LEP on the crop-gizzard of the earthworm. Analog peptides of LEP and EEP-2 were synthesized, and the myoactive potency of each analog on the leech and earthworm tissues was compared.     

Pentacene thin film transistors fabricated by solution process with directional crystal growth

We have fabricated solution-processed pentacene thin film transistor arrays with mobilities as high as 1.0 cm²/V s, evaluated at a low drain voltage of ?10 V. This is achieved by controlling the growth direction of the pentacene films from solution, and by optimizing conditions for drop casting. Crystal growth of the solution-processed pentacene films is found to proceed in one direction on a tilted substrate. Grazing incidence X-ray diffraction and electron diffraction reveal that the crystal growth azimuth corresponds to the direction along the minor axis of the a–b plane in the unit cell of the pentacene crystal. This directional growth method is extended to solution processing on large glass substrates with an area of 150 × 150 mm², thereby yielding transistor arrays with two-dimensional uniformity and high carrier mobility.     

Structures and electronic properties of thin-films of polycyclic aromatic hydrocarbons

We report the fabrication and characterization of organic thin-film transistors (TFTs) using several polycyclic aromatic hydrocarbons (PAHs). Pentacene, ovalene, dibenzocoronene and hexabenzocoronene were deposited as organic semiconductors on silicon wafers with gold electrodes as the bottom-contact configuration of the TFTs. The pentacene TFT showed the highest field-effect mobility of more than 0.1 cm²/Vs in comparison with the other PAHs. The results clarified that the high field-effect mobility of the pentacene thin film is due to large grain size and intrinsic electronic properties.