Localized thermal processing with a laser‐trapped and heated metal nanoparticle

We report localized thermal processing using a laser‐trapped and heated metal nanoparticle. A metal nanoparticle trapped by a focused, continuous wave (CW), near‐infrared laser was heated by photothermal conversion and acted as a remotely controllable nanosized thermal tool for processing a workpiece. We demonstrated the processing of a glass substrate with an optically trapped gold nanoparticle (diameter 200 nm) irradiated by a Nd:YAG laser (λ = 1.064 µm, CW). Laser irradiation caused local melting of the substrate and a crater‐like nanosized imprint on the substrate, demonstrating thermal nanoprocessing of an optically transparent material. Copyright © 2007 Institute of Electrical Engineers of Japan© 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Miniaturised 45° power divider using three-dimensional MMICtechnology

A miniaturised 45° power divider using three-dimensional MMIC technology is described. The divider comprises stacked thin-film microstrip lines that sandwich a ground plane between them. It has an area of only 0.43 mm², and it exhibits a coupling of 4.5±0.2 dB and a phase difference of 45±1° from 28 to 33 GHz     

Steady‐state N2O decomposition on Pt and Rh surfaces using a free‐jet molecular‐beam excited by nozzle heating

Steady‐state N₂O decomposition reaction on polycrystalline Pt and Rh surfaces has been studied using a supersonic free‐jet molecular beam (2.1 × 10¹⁸ molecules/cm² s). The energy of the incident N₂O beam was controlled by a nozzle heating technique in conjunction with a seeding technique. The decomposition rate shows both translational and vibrational energy dependence on the Pt surface. However, there is also the surface temperature dependence of the decomposition rate even varying the incident beam energy, indicating precursor‐mediated dissociation of N₂O on the Pt surface. On the other hand, no energy dependence was observed on the Rh surface, suggesting that the decomposition dynamics are different between Pt and Rh surfaces. This revised version was published online in August 2006 with corrections to the Cover Date.     

Estimation of Magnetizing Characteristics of Pole Transformers in Islanding Area

For the detection of islanding, it is very important to choose the threshold value for the change in the harmonic voltage. In this paper, we propose an analytical model of a pole transformer using a Fourier series and clarify the nonlinear magnetizing characteristics of the pole transformer in an islanding area. After determining the proposed model coefficients from the tests of the pole transformer excited by a sinusoidal voltage, distorted wave voltage tests were performed under conditions in which the third harmonic voltage or the fifth harmonic voltage was superimposed. The results of the testing showed that the magnetic properties vary greatly upon increasing the harmonic component of the voltage. The analytical and measurement results were in good agreement. By using the proposed method, the distributed generators (DGs) can estimate the magnetizing characteristics of the pole transformer by monitoring the connected terminal voltage. Thus, as an active signal for islanding detection, DGs can inject a harmonic current synchronized to the excitation current harmonics of the pole transformer into the distribution network. In the case of DGs equipped with the above functions, there is no need to change the settings of the islanding detection threshold for changes in the harmonic voltage even when there is a change in the excitation voltage or an increase in the number of DGs.     

Method of evaluation of distribution characteristics of flaky inclusions*

In order to evaluate the maximum size of the flaky inclusions in a Si-added noncombustible Mg casting alloy, we propose a method for evaluation of distribution characteristics of flaky inclusions. The validity of this method is verified through simulations with arbitrary inclusion distributions. The proposed method enables prediction of the maximum size of the flaky inclusions in an arbitrary volume of material.     

Distribution of a novel angiotensin I-converting enzyme inhibitory substance (2″-hydroxynicotianamine) in the flour,plant parts,and processed products of buckwheat

2″-Hydroxynicotianamine (HNA) is a recently discovered angiotensin I-converting enzyme inhibitory compound present in buckwheat which displays hypotensive activity. Here, HNA levels in buckwheat flour, plants, and products were quantified to examine the potential functionality of this food. The HNA content of buckwheat flour ranged from 16–28 mg per 100 g dry weight. When the content was evaluated by the milling stage, common buckwheat contained 24.3, 24.1, and 34.1 mg in the inner, middle, and outer layers, respectively, whereas tartary buckwheat contained 16.8, 30.5, and 51.8 mg of HNA, respectively. Comparison of the distribution of HNA within buckwheat plants revealed that HNA was predominantly localised in seeds (buckwheat flour). The residual HNA levels after cooking ranged from 21% to 41% in dried buckwheat noodles. This study clarified that buckwheat flour contains high levels of HNA and is a readily available source of HNA if incorporated into one’s diet, which may help reduce hypertension.     

High hydrostatic pressure treatment impairs AcrAB-TolC pump resulting in differential loss of deoxycholate tolerance in Escherichia coli

We reported previously that high hydrostatic pressure-injured stationary phase cells of Escherichia coli K-12 lost their intrinsic deoxycholate tolerance. The AcrAB-TolC multi-drug resistance pump driven by proton motive force has been argued to be responsible for the tolerance to deoxycholate. In this report, we tested the sensitivity of the AcrAB-TolC (three components) pump to high hydrostatic pressure treatment (HPT). E. coli K-12 treated with HPT became sensitive to AcrAB-TolC-specific drugs such as ethidium bromide, but not to tetracycline which is pumped out by a one-component transporter, Tet. Only E. coli K-12 overproducing both AcrAB and TolC exhibited restored tolerance to deoxycholate after HPT but not E. coli overproducing either TolC or AcrAB. These observations strongly suggest that three-component pumps such as AcrAB-TolC are more susceptible to HPT than one-component pumps such as Tet, resulting in the differential loss of deoxycholate tolerance in high hydrostatic pressure-injured E. coli cells.     

Fabrication of Ge nanoneedles by ion-irradiation method

The Ge surfaces irradiated by Ar⁺ ions at 600 eV with simultaneous Ni supply at room temperature were characterized by various kind of densely distributed nanostructures, such as tiny cones, nanorods with a bottlenecked and nanoneedles, depending on the Ni supply rate during Ar⁺ ion irradiation. As the Ni supply rate decreased, the width of nanostructure formed on the cone tip became thin, and finally slender Ge nanoneedles of 60-80 nm in diameter and 100-300 nm in length were realized. Because the simultaneously supplied Ni fulfills the prerequisite for the so-called “seed” which enhances the surface texturing, size of clustered Ni atoms during of Ar⁺ ion irradiation might affect the size of nanostructures formed after the prolonged sputtering.     

Fully automated on-chip imaging flow cytometry system with disposable contamination-free plastic re-cultivation chip

We have developed a novel imaging cytometry system using a poly(methyl methacrylate (PMMA)) based microfluidic chip. The system was contamination-free, because sample suspensions contacted only with a flammable PMMA chip and no other component of the system. The transparency and low-fluorescence of PMMA was suitable for microscopic imaging of cells flowing through microchannels on the chip. Sample particles flowing through microchannels on the chip were discriminated by an image-recognition unit with a high-speed camera in real time at the rate of 200 event/s, e.g., microparticles 2.5 μm and 3.0 μm in diameter were differentiated with an error rate of less than 2%. Desired cells were separated automatically from other cells by electrophoretic or dielectrophoretic force one by one with a separation efficiency of 90%. Cells in suspension with fluorescent dye were separated using the same kind of microfluidic chip. Sample of 5 μL with 1 × 10(6) particle/mL was processed within 40 min. Separated cells could be cultured on the microfluidic chip without contamination. The whole operation of sample handling was automated using 3D micropipetting system. These results showed that the novel imaging flow cytometry system is practically applicable for biological research and clinical diagnostics.     

Hydrogenolysis of sugar beet fiber by supported metal catalyst

Sugar beet fiber is an agricultural by-product in the sugar manufacturing and an available biomass source with a rich hemicellulose component. So far, there has been no report on the catalytic conversion of the beet fiber for the synthesis of chemicals. In this work, the hydrogenolysis of the beet fiber was studied by using supported metal catalysts under pressurized hydrogen conditions. Activated carbon supported Ru was found to show the highest catalytic activity to give arabitol as a major product in the hydrogenolysis of hemicellulose part of this material. The reuse ability of the catalyst was also investigated.