Synthesis and electronic property of platinum nanowire and nanoparticle in mesoporous silica template

Platinum nanowires and nanoparticles were selectively synthesized in mesoporous silicas FSM-16 and HMM-1. The nanowires are 3 nm in diameter and several hundred nm to μm in length with high crystallinity. Pt nanowires and nanoparticles can be isolated by dissolving silica matrix with HF. The Pt wires extracted from organosilica HMM-1 have a nanonecklace structure, while the wires from siliceous FSM-16 have a nanorod structure. The extracted Pt nanoparticles (3 nm in size) on HOPG show the Coulomb staircase phenomena in STM/STS analysis. The mechanism for formation of the Pt nanowires is based on the migration of Pt ions in the mesoporous channels.     

Impact of fertilizer on a small watershed of Lake Biwa: use of sulfur and strontium isotopes in environmental diagnosis

Sulfur and strontium isotopes (delta(34)S and (87)Sr/(86)Sr) were determined in 39 river water samples collected over three different cultivation periods (April, May, and June), and in several materials used for comparison (fertilizers, detergents, soils, irrigation and agricultural waters), to evaluate the impact of fertilizers on a small agricultural watershed of Lake Biwa, in central Japan. delta(34)S values in river water decreased (from +5.8 to -2.0 per thousand) with increasing SO(4) concentrations (3.8 to 93.2 ppm) from upstream to downstream of the watershed. Comparison of river water S isotopes with those of possible source materials indicates that the enrichment of SO(4) can be attributed to the dissolution of two kinds of fertilizers: (1) compound fertilizers commonly used in this area and (2) ammonium sulfate which is applied on a small scale. In contrast, (87)Sr/(86)Sr values of river water decreased with time from April (avg. 0.71163), through May (avg. 0.71139), to June (avg. 0.71127). The tendency of the sample plots on the (87)Sr/(86)Sr vs. 1/Sr diagram suggests a time-dependent increase in the contribution of soil water to the river, which is partly affected by the Sr-bearing fertilizers. It is suggested that a maximum of 25% of dissolved Sr is derived from these fertilizers, while more than 75% of it is of rock origin. Mass balance calculations permitted us to evaluate the proportion of fertilizer contribution in each river. Combined use of S and Sr isotopes together with concentration data could be a new environmental diagnosis technique for rivers and soils in localized watersheds.     

Stacking faults in an epitaxially grown PbTiO3 thick film and their size distribution

The microstructure of an epitaxial PbTiO₃ thick film, grown on a SrRuO₃/SrTiO₃ substrate at 600 °C by pulsed-MOCVD method, was investigated by using transmission electron microscopy. A number of extrinsic or intrinsic stacking faults were observed in the epitaxial PbTiO₃ thick film and they were parallel to the (0 0 1) plane of the PbTiO₃. We also investigated the size distribution of these stacking faults. The width of these stacking faults along the [1 0 0] axis of the PbTiO₃ was very small, ranging from 2 to 13 nm. It was also revealed that the size distribution of stacking faults depends on the position in the film: near the surface, near the substrate, near threading dislocations, and near 90° domain boundaries.     

Controller design of desktop-size NC machine tool with multi-application function

In this paper, a desktop-size NC machine tool is first presented to have multi-application function, such as 3D-machining modes with and without handling a machining force, and profiling-control modes with and without using stick-slip motion. The NC machine tool consists of three single-axis devices with a high resolution of 1???m in position. A ball end mill called router bit or a thin wood-stick tool can be attached to the tip of the z-axis. The proposed machine tool realizes compliant motion required for the profiling control along a desired trajectory. The profiling-control mode can be applied to the lapping process of a metallic LED lens cavity. Next, a control strategy with fine stick-slip motion is further added to the profiling-control system to improve the lapping performance. The fine stick-slip motion is generated orthogonally to the direction of the tool movement. Generally, the stick-slip motion is an undesirable phenomenon to be eliminated in precision machineries. However, the proposed machine tool employs the fine stick-slip motion to partly regulate slight finishing energy. The effectiveness of the machine tool is demonstrated through an actual machining test of a wood material and a lapping test of a metallic LED lens cavity.     

Effect of Sliding History on Super-Low Friction of Diamond-Like Carbon Coating in Water Lubrication

Water lubrication using diamond-like carbon (DLC) coatings is regarded as being a promising eco-friendly technology. However, it has been reported that delamination of DLC coatings occurs in water. The authors clarified that the application of friction in ambient air prior to self-mating DLC water lubrication, in addition to the suppression of DLC delamination, caused the friction coefficient to decrease more than when no processing is performed in the boundary lubrication region. When compared to the case when there was no pre-sliding, in terms of the wear scar, in this case, a much more hydrophilic and smoother surface was formed. Therefore, the friction-reducing process in water due to the presence of a sliding history (pre-sliding in ambient air) was clarified by an analysis of the DLC geometry, structure, chemical state and an in situ analysis that can measure the friction properties and the chemical state of DLC. We clarified that the process in which the oxidation and structural changes of the DLC proceed at the time of pre-sliding in ambient air using in situ Fourier transform infrared spectroscopy–attenuated total reflection. It was also revealed that the OH termination subsequently accelerated rapidly due to the friction in water after pre-sliding process. In addition, a time-of-flight secondary ion mass spectrometry analysis revealed that this OH group was derived from the lubricating water and unlike the case in which there was no pre-sliding in ambient air, the rate at which OH terminates increased considerably.     

Superconductivity in W-containing diamond-like nanocomposite films

Superconductivity in a tungsten-containing carbon-oxide film was reported. The film with 500 nm thickness was deposited onto polycrystalline silicon oxides using chemical vapor deposition and the co-sputtering of a tungsten metal target. The bonding state of the carbon atoms and the macroscopic and microscopic crystal structure of the film were investigated by Raman spectroscopy, X-ray diffraction and transmission electron microscopy measurements. From the experimental results, we determined that this film essentially had an amorphous structure. The temperature dependence on resistivity was measured in the temperature range of 2–300 K. Resistive superconducting transition was observed at 3.8 K. The dc magnetizations were measured in the temperature range of 1.8–6.5 K. The diamagnetism resulting from a superconductive state was observed below 3.75 K, which is consistent with a resistive superconducting transition. It is thought that the finite sized clusters of the different superconductive transition temperatures cooperatively produce a macroscopic superconducting phenomenon.     

Partial oxidation of ethane to synthesis gas over Co-loaded catalysts

Attention has been increasingly paid to the partial oxidation of lower alkanes to synthesis gas, due to its intrinsic energy saving process. We studied the partial oxidation of ethane (POE) on Co loaded on various supports. The POE performance varied as follows: Y₂O₃, CeO₂, ZrO₂, La₂O₃  SiO₂, Al₂O₃, TiO₂ > MgO. Comparing Y₂O₃ and CeO₂, the carbon deposition during the POE was negligible on CeO₂ and therefore CeO₂ was the most preferable support. By changing space velocity and O₂ partial pressure, reaction mechanism of POE was studied and it was revealed that two-step mechanism was prevailing; combustion of ethane to H₂O and CO₂ and subsequent reforming of ethane with H₂O and CO₂ to synthesis gas. Co/CeO₂ catalyst exhibited high and stable catalytic activity for 10 h; high ethane conversion of 18% (maximum ethane conversion 20% at O₂/C₂H₆ = 0.2) with H₂ and CO selectivities of 93 and 84%, respectively.     

Accumulation of triosephosphate isomerase, with sequence homology to Beta amyloid peptides, in vessel walls of the newborn piglet hippocampus

We investigated whether beta-amyloid (Abeta)-like immunoreactivity was seen in the brains of newborn piglets. The immunoreactivity for Abeta(1-42) and Abeta(1-40) proteins, but not Abeta precursor protein, was present in CD68-positive perivascular cells of the hippocampus and in parts of the meninges. It was colocalized with immunoreactivity for receptor for advanced glycation end product and tumor necrosis factor-alpha. The protein with a molecular mass of 27 kDa, which was recognized by the Abeta antibodies, was identified as triosephosphate isomerase (TPI) with sequence homology to Abeta peptides by N-terminal amino acid sequencing, mass fingerprint analysis using matrix-associated laser desorption/ionization mass spectrometry, and Western blotting. Western blotting assay also revealed that detectable expression of Abeta proteins were not seen in the piglet brains. These findings indicate that TPI with sequence homology to Abeta peptides accumulates in perivascular cells of the microglia/macrophage lineage located around arterial vessels of the newborn piglet hippocampus.     

Demand creation and location: a variable consumer-distribution approach in spatial competition

This paper deals with a variable spatial distribution of consumers according to the location decisions of firms in spatial competition. Specifically, we present a location-then-quantity game in which some of the consumers are attracted to the firms’ locations. We show that all firms agglomerate in a circular city when the transport cost is low. This is in sharp contrast to the results shown in previous studies with fixed distributions of consumers, where such a full agglomeration never occurs in equilibrium. Welfare analysis shows excess dispersion compared with the second-best scenario.     

Mechanical role of reinforcement in seismic behavior of steel-strip reinforced earth wall

In the current design practices of steel-strip reinforced earth walls (SSREWs), the length of the reinforcing material is determined based on the equilibrium between the reinforcement tension and the earth pressure acting on the wall. Here, the resistance of the reinforcing material laid in the active failure zone (AFZ) is not considered. Moreover, the mechanical role of the reinforcing material against the integrity of the SSREW has not been sufficiently verified. Regarding the seismic stability of SSREW, although it is investigated by treating the entire reinforced earth wall as a rigid body, this inspection method is for gravity-retaining walls, and the difference in the seismic behavior between the SSREW and the rigid body is not clear. In this study, therefore, dynamic centrifuge model tests on 6 types of SSREWs were conducted to clarify the following items: (1) the basic earthquake behavior of a SSREW, (2) the mechanical role of the reinforcing material laid in the AFZ and (3) the mechanical role of the reinforcing material against the integrity of the SSREW. The results indicated that the reinforcing material laid in the AFZ can restrain the amount of deformation of the wall during earthquakes. Furthermore, the more stable the AFZ is, the smaller the maximum wall displacement will be.