High Power,Frequency Tunable,Submillimeter Wave ESR Device Using a Gyrotron as a Radiation Source

ESR device using a submillimeter wave gyrotron as a radiation source and a pulse magnet for high field up to 30 T has been constructed. Our gyrotrons (Gyrotron FU series) were developed as millimeter and submillimeter wave radiation sources and have attractive advantages for ESR spectroscopy, for example, high power and frequency tunability over broad range. The ESR device has been successfully applied to three cases of ESR measurements. In the first case, the temperature dependence of ESR was measured for a typical antiferromagnetic material MnO at the frequency of 301 GHz. In the second case, the dependence of the fine structure constant of the ruby on the magnetic field intensity was measured in the millimeter to submillimeter wave region. In these two cases, the gyrotron was operated by complete cw mode. In the final case, a pulse technique was applied to the ESR, the gyrotron was operated in pulse mode and the pulsed magnetic field was generated in the synchronized phase with the gyrotron operation.     

Effects of phosphorus content on generation and growth of cracks in nickel–phosphorus platings owing to thermal cycling

We observed crack generation and structural changes in electroless nickel–phosphorus (Ni–P) plating layers formed on copper-metalized silicon nitride substrates both during thermal cycling from ? 40 to 250 °C and during storage (not cycling) at 250 °C in order to investigate the effect of the phosphorus contents on crack generation and growth in the Ni–P platings. The used platings contained phosphorus at three different contents: 2.1 wt% [Ni–P(low)], 6.5 wt% [Ni–P(med)], and 10.9 wt% [Ni–P(high)]. The generation time and the amount of cracks were strongly dependent on their phosphorus contents. More cracks appeared after thermal cycling than after storage at 250 °C. In Ni–P(low), cracks were generated after 200 thermal cycles, whereas no cracks were observed even after 250 h of storage at 250 °C. In Ni–P(med) and Ni–P(high), both during thermal cycling and storage at 250 °C, cracks formed during or after crystallization of the amorphous layers. These results suggest that the primary factors affecting the generation of cracks in electroless Ni–P platings are crystallization of the Ni–P platings and repeated changes in thermal stress.     

High-performance carbon counter electrode for dye-sensitized solar cells

Here, we reported that a new carbon electrode prepared with an activated carbon was superior to a Pt sputtered electrode as the counter electrode of dye-sensitized solar cells. The photovoltaic performance was largely influenced by the roughness factor of carbon electrode. The open-circuit voltage increased by about 60 mV using the carbon counter electrode compared to the Pt counter electrode because of positive shift of the formal potential for I₃⁻/I⁻ couple.     

Depression of melting point of eutectic metal alloy by the interaction with polyacrylates in metal-polymer composites

The composites of polyacrylates and eutectic metal alloy composed by Bi, In, and Sn were prepared by mixing the metal and polymer above the melting point of the metal alloy (80 °C) with a homogenizer. Two melting peaks, which were assigned as the melting peak of the original metal alloy and that of the interfacial phase of the metal alloy interacting with polyacrylates (70 °C) by differential scanning calorimetry. Metal particles with the diameter of about 100 nm which were stabilized by the interfacial interaction with polyacrylates were observed by transmission electron microscopy. The melting peak at 70 °C was assigned as the melting peak of these small particles.     

Applying heat integration total site based pinch technology to a large industrial area in Japan to further improve performance of highly efficient process plants

“Area-wide pinch technology” which consists of R-curve analysis and Site Source Sink Profile (SSSP) analysis, was applied to Kashima industrial area, one of the biggest heavy chemical complexes in Japan. This case study demonstrates that despite the very high efficiency of the individual sites in the complex, there is a huge amount of energy saving potential through energy sharing among the various sites. In addition it was found that appropriate use of the available pinch technology tools and techniques allows an industrial area of enormous scale and complexity to be analysed conveniently. This has resulted in practical area-wide energy saving projects being proposed and implemented.     

High-Performance Induction Motor Drive System Using a PWM Inverter

A high-performance speed control system for cage induction motors is described which utilizes a PWM inverter. The effects of primary current coincidence and machine constant variation on system characteristics such as response time, torque precision, and operating noise were investigated. Based on the results obtained, new control methods have been devised; one varies the gain of the current controller in proportion to the primary frequency, and a second compensates for the slip frequency by using the deviation between the flux reference value and the actual value. Effectiveness of the compensation methods was confirmed in tests.     

Determination of free fatty acids in milk and dairy products by reversed-phase HPLC with fluorescence detection

A highly sensitive HPLC with fluorescence detection was developed for the determination of free fatty acids (FFAs) in milk and dairy products. For this purpose, the FFAs were extracted from small amounts of milk (1.0 mL), cheese (0.5 g) and butter (0.5 g) using Sep-Pak cartridge columns, and then derivatized to 9-anthrylmethyl esters with 9-anthryldiazomethane (ADAM). Good separations of the ADAM derivatives of 16 FFAs (C4-C18) that exist in milk, cheese and butter, which permitted quantitative estimation of their individual FFAs, were achieved by HPLC on a C18 column (Cadenza CD-C18, 150 x 3 mm i.d.) using gradient elution with methanol and water. The acid values calculated from the contents of individual FFAs were in good agreement with those obtained by the conventional titration method. These results demonstrate that the present HPLC method is simple, sensitive and precise, and could be utilized widely for determination of the FFAs in milk and dairy products.     

Numerical analysis of plasmon-resonance absorption in bisinusoidal metal gratings

We numerically investigate plasmon-resonance absorption of incident light energy by a bisinusoidal metal grating, i.e., one whose surface profile is sinusoidally corrugated in two orthogonal directions with a common period. Employing Yasuura's modal expansion method, we solve the problem of plane-wave diffraction by the grating and evaluate the absorption, which is observed as dips in diffraction efficiency curves. We examine the field distribution and energy flow in detail at the angles of incidence at which the absorption occurs. We show that the absorption is caused by coupling of the TM component of an evanescent order with surface plasmons. A phase-matching condition is used in the prediction of the incident angle at which the absorption occurs. This, together with the field profile in the presence of the resonance absorption, explains the mechanism of the absorption. We then illustrate interesting features of the absorption: enhancement of polarization conversion between the incident light and the reflected light and simultaneous excitation of two plasmon waves in directions that are symmetric with respect to the plane of incidence.     

Infrared sea surface emissivity including multiple reflection effect for isotropic Gaussian slope distribution model

A method is described for incorporating surface-emitted surface-reflected (SESR) radiation into the calculation of infrared sea surface emissivity. Firstly, the direct emissivity is obtained by ignoring SESR emission. Next, the first order SESR emissivity is obtained by using the direct emission as a radiation source. Finally, the ith order SESR emissivity is iteratively obtained by using the i − 1st order SESR emission.Computational results are in good agreement with a Monte Carlo calculation, where the SESR emissivity increases from an emission angle of 50° showing a maximum value of about 0.03 at an emission angle of 80°. The direct emissivity is smaller than the measured emissivity by 0.02∼0.03 around a wavelength of 10 μm at an emission angle of 73.5°. By incorporating the SESR emission into the emissivity model, the discrepancy between the computed and the measured emissivity is significantly reduced.The advantage of the present method over the previous works is that we need not to specify a cutoff angle to differentiate the radiation from the sea and that from the sky for calculating SESR emission. Instead of using a cutoff angle, the probability that radiation originates from the sea is derived from the probability distribution function of sea surface slope. As a result, the uncertainty in the computation of sea surface emissivity attributed to the uncertainty in cutoff angle could be effectively suppressed.     

Aggregate formation of rCHO cells and its maintenance in repeated batch culture in the absence of cell adhesion materials

Aggregate formation of recombinant Chinese hamster ovary (rCHO) cells capable of producing granulocyte colony-stimulating factor (G-CSF), using medium lacking cell adhesion materials in a repeated batch culture, was examined together with cell growth, cell viability and G-CSF production. The rCHO culture was conducted in a rotary shaker and the medium was changed every five days. The formation of stable cell aggregates with high reproducibility was observed after the first medium change. The size of the cell aggregates (consisting of several 10s to 40,000 cells) formed during the repeated batch culture ranged from 30 to 600 microm. The cell density of the aggregates reached as high as 2 x 10(6) cells/ml and the viability was maintained at more than 80% for 19 d. Changing the medium to avoid glucose exhaustion effectively maintained the cell density, cell viability and G-CSF productivity at high levels.