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In electrochemical CO2 reduction reactors, polymer electrolyte membrane (PEM) reactors, also known as zero-gap cells, have great potential for achieving significant CO2 reduction. Because these cells have a thin reactor core with a thickness of several hundred micrometers, it is difficult to determine their internal voltage distribution. To determine the anode voltage, ohmic loss in the membrane, and cathode voltage in the PEM reactors, we set three reference electrodes in the reactor and investigated the voltage values obtained from each reference electrode. We demonstrated that the reference electrode in contact with the anion exchange membrane extending to the outside of the cell provides the most reliable voltage. The voltage measured by this reference, combined with the resistance of the exchange membrane obtained through electrochemical impedance spectroscopy, provides a breakdown of the voltage inside the cell.

Electric-field-induced anti-Stokes Raman scattering in the visible region (E-CARSv) is a third-order nonlinear optical effect used for measuring electric field sensitively, especially at atmospheric or higher pressure. This study demonstrated E-CARSv generation from nitrogen molecules using a visible laser at 532 nm, a tunable infrared laser at approximately 4.3 μm, and an applied DC electric field. The results revealed that the square root of the signal intensity was proportional to the external electric field strength, which corresponded with the theoretical prediction. E-CARSv can be applied to a wide range of mediums containing nitrogen molecules, including plasmas generated in an open-air environment.

The reactive gas cluster injection process is an etching method that uses a neutral cluster beam without plasma. This process can avoid damage caused by energetic ion irradiation and vacuum UV light from the plasma. The characteristics of an etching by ClF3–Ar gas cluster injection were investigated at various target distances, pattern widths, and sample temperatures. As a result, the relationship between the etching conditions and the aspect ratio was clarified, and an equation that can predict the maximum limit of the aspect ratio was derived from the ClF3 flux and pattern widths. Then high aspect etching with an aspect ratio exceeding 20 is realized. And also, the 3D lever structure of 6 layers can be fabricated by double-angled etching with neutral cluster injection at the condition for high aspect etching.

A balancing group is an intermediate layer between the market and demand sides playing a key role in maintaining the demand and supply balance within the group after the massive penetration of photovoltaic (PV) systems. In this paper, the balancing group formulates an optimal plan to guarantee a highly efficient operation of conventional generators and the group's maximum output from PV generators simultaneously. The aggregator is provided a planned power flow (PPF) via a communication network by the balancing group in advance. Under these prerequisites, we propose a two-stage scheme for the demand side that consists of a day-ahead allocation algorithm of PPF and a real-time battery energy storage system (BESS) operation algorithm. The first stage of the scheme is almost the same as the case of the centralized effective BESS control, taking into account the maximum use of distributed BESSs. Owing to consumers' demand diversity, the second stage of the scheme refers to a distribution generated using past data to reduce wasteful operation. The proposed approach is verified via a numerical simulation using a measured dataset from Ota City, Japan.

The application of an electrochemical method to the iron-based chalcogenide superconductors has great potentials in enhancing their properties such as the superconducting transition temperature. Unfortunately, this method has been limited to polycrystalline powders or thin film samples with a large surface area. Here, we demonstrate that the electrochemical method can be usefully applied to single-crystal devices of FeSe1− x Te x superconductors by combining it with the focused ion beam (FIB) microfabrication techniques. Our results open a new route to developing the high-quality superconducting devices fabricated using layered iron-based chalcogenides, whose properties are electrochemically controlled.

Overcrowded ethylene 1 shows mechanochromic behavior with contrasting color change between yellow and violet arising from its conformational isomerization, which should also be accompanied by the change in the electronic structure. Here, we report a single-molecule electronic study of 1 using scanning tunneling microcopy (STM) and STM-based break junction techniques. The single-molecule junction of 1 sandwiched by Au electrodes showed two distinct high- and low-conductance states with the conductance values of 0.003 and 0.0002 G 0. The high-conductance state is one order of magnitude more conductive than the low-conductance state. The two states can be ascribed to two conformational isomers of 1 in the junction.

A simulation model of concentrated colloidal rod-like nanoparticles is developed. As the governing equation of motion of a nanoparticle, the Langevine equation with external force is used. The external force includes capillary force, contact force, electrostatic force, van der Waals force, and elastic force which occurs inside an elastic rod. Numerical simulations are performed for the system of concentrated colloidal rod-like nanoparticles, which experiences solvent evaporation with a constant rate. Consequently, some structures of self-organized rod-like nanoparticles are obtained for the specified aspect ratios. The time evolution of the system is quantitatively analyzed by using the orientational order parameter and the non-dimensional boundary area. Moreover the two quantities are found to resolve the structures obtained in the simulation.

In order to apply the dual-energy technique to material identification, a new computed tomography scanning system was proposed using a conventional X-ray tube and a CdTe detector. This system can provide information of projection data at two distinct energy bands for scanned materials. After introducing an approximation, the measured projection data were reconstructed to obtain the distributions of the X-ray linear attenuation coefficients of the materials at two different energies. Then, the corresponding atomic number and electron density can be derived with the dual-energy X-ray computed tomography (DXCT) method adopted. By comparing the obtained results with theoretical ones, the feasibility of using this system for identifying low-Z materials was demonstrated in this study.

In this paper, the fundamental optical properties of photonics polymers are reviewed on the basis of the relationship between lightwave and polymer materials. We have proposed and demonstrated photonics polymers with new optical functions for applications in microoptics fields, such as graded-index plastic optical fibers (GI POFs), highly scattered optical transmission (HSOT) polymers, zero-birefringence optical polymers, and graded-index plastic optical fiber amplifiers (GI POFAs). In the materials we proposed, the lightwave refracts, scatters or polarizes according to the size of heterogeneities of refractive index within the polymer matrix. With these photonics polymers, we propose the concept of "fiber to the display", which will lead us back to "face-to-face communication".

The adhesion strength of Cu/(Ta–x% N, Ta/TaN)/SiO2/Si was investigated and the feasibility of the nanoscratch technique was evaluated. Because of the grain orientation dependence of critical load owing to elastic/plastic anisotropy, the interface adhesion measured in the mix-textured films of and showed a wide-range data spread to higher adhesion strength compared with the highly textured films. The adhesive energy derived from the measured critical load by considering the residual stress and the effect of grain orientation by the aid of finite element method calculation showed a reasonable agreement with theoretical work of adhesion. It was revealed that the adhesion strength of Cu/Ta–x% N decreases with increasing nitrogen concentration. This tendency can be associated with increasing number of weak Cu–N bonding along the Cu/barrier interface.

Mechanical processes of the nanoscratch test are investigated using a finite element analysis of Cu/Ta/SiO2/Si multilayer films. The calculated stress distribution at the moment of delamination suggests that delamination occurs in a small region of approximately 100 nm. The driving force for delamination is the stress concentration due to strain-incompatibility at the Cu/Ta interface resulting from the large plastic deformation in Cu. The degree of stress concentration is found to depend on internal variables, such as plastic deformation, residual stress, and the elastic modulus, and on the magnitude of lateral force.

We have demonstrated the laminated organic light-emitting devices (OLEDs) with a MgAg precoated poly(ethylene terephthalate) (PET) film. The MgAg-coated PET film maintained a low work function after several days of storage. Although the performance of the laminated OLEDs strongly depended on the adhesion of the cathode film, the best performance of the laminated OLED with the PET cathode film based on poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) showed comparable performance to the cathode vacuum deposited reference device. The electronic junction formed by lamination might still be inferior to that formed by the thermal evaporation of metals at present from the viewpoint of operation voltage. However, the comparable current efficiency and maximum luminance of the laminated OLED implied that the prepared PET with the MgAg cathode probably maintained a high activity. We believe that better laminated OLEDs might be obtained if better light-emitting polymers are employed.

It is shown that a shear vertical (SV) wave propagating along a surface of a test object can be transmitted and received by angle probes whose angle of refraction is close to a critical angle. In order to investigate this phenomenon, simulation is carried out using the finite difference time domain method. According to the acoustic fields obtained by the simulation, the beam width of a SV wave increases with propagation, and energy associated with the SV wave exists at the surface. Therefore, the transmitted pulse can be received. The phenomenon of SV wave propagation is referred to as SVC (SV wave for a critical angle). This simulation result is verified by an experiment, which showed that the transmitted pulse is applicable to the measurement of SV wave velocity.

Changes in rheological properties of fumed silica particles dispersed in aqueous KOH solution at pH 11 by the addition of KCl have been studied as functions of the silica and KCl concentrations. Since the fumed silica particles are stable in the state of aggregates of the primary particles, coagulation of such aggregates by addition of KCl should cause a gel. Thus, the resulting gel can be regarded as the weak-link gel according to the fractal gel model. States of the fumed silica suspensions in the presence of KCl were roughly classified into four phases, such as sol (S), pre-gelled (PG), gelled (G), and two-phase separated (TP) silica suspension from visual observation. The PG and G silica suspensions were conducted by strain and frequency sweep measurements of dynamic moduli, whereas the S silica suspensions were mainly examined by steady-state viscosity measurements. The critical strains obtained from the strain sweep measurements of storage modulus G' were almost independent of the silica volume fraction at lower KCl concentrations than 0.4 M, whereas they increased with the positive power-law of at higher KCl concentrations than 0.5 M. The positive power-law exponent is in agreement with the prediction for the weak-link gel. The PG and G silica suspensions show that the G' values in the linear response regions indicate little frequency dependence. The values of G' at the fixed KCl concentration exhibit a power-law behavior and the resulting power-law exponent increases with an increase in KCl concentration.

We studied the characteristics of Mott scattering systematically by constructing a special chamber, where target film thickness and the position of electron detectors can be controlled by an engineering workstation using stepping motors. Using this instrument, key parameters such as effective Sherman function and intensity were measured as functions of the scattered electron energy, target film thickness, and electron scattering angle. In the range of the electron energies we studied, i.e., 60–120 keV, a lower energy is preferable to achieve a large figure of merit. The results are compared with previously reported simulations.

In this paper we showed electron projection lithography (EPL) applicability to via formation in a back-end-of-line (BEOL) process for 45-nm technology node through fabricating a two-layer metallization device. We developed a single-layer via-resist process for 45-nm technology node. In order to prevent resist profile deteriorations, we optimized process conditions of a bottom anti-reflective coating (BARC) and an electrical conductive film (ECF). As a result, fine 60-nm (1:1) via-patterns were obtained after low-k dry-etching and 67-nm via-holes filling with Cu could be confirmed by using cross-sectional transmission electron microscope (TEM). These results suggested the single-layer via-resist process we developed could be applied for 45-nm technology node. In addition, for 32-nm technology node, we developed a tri-layer via-resist process that had a high resolution compared with a single-layer resist process. There, we could obtain extremely fine 40-nm (1:1) top-layer via-resist patterns. We believe that EPL has high applicability to via formation in BEOL process for not only 45-nm but also 32-nm technology node.

GaN striped structures along the and directions were fabricated by a combination etching technique, consisting of reactive ion etching followed by KOH wet etching. After wet etching, the sidewalls of the striped structures along the direction became very smooth and straight, compared with normal wet etching and dry etching. From the differences of the etching along the direction, it was found that etching mainly occurs in the (1 100) plane. This phenomenon can be explained by the action of OH- ions, which are repelled by N dangling bonds on the surface and which attack Ga back bonds as well as the mechanism of (000 1) polar GaN etching.

Accepted: 2005-11-23, 資料番号: SA1000507000

Pseudocubic SrRuO3 (100) epitaxial thin films were fabricated on Si (100) with a SrO buffer layer by pulsed laser deposition (PLD). Reflection high-energy electron diffraction (RHEED) revealed that the SrO layer is epitaxially grown on naturally oxidized Si substrates with an orientation relationship of SrO (110)/Si (100) and SrO //Si . Subsequent SrRuO3 deposition resulted in a (100) epitaxial thin film possessing good crystallinity with a full-width at half maximum (FWHM) of 1.9° in the SrRuO3 (200) rocking curve by X-ray diffraction (XRD). Based on the Gibbs free energy change in the reaction of silicon with alkaline earth metal oxides, deoxidization of SiO2 on Si by Sr is thought to play an important role in the epitaxial growth of SrO. Cross-sectional observation for the optimized SrRuO3/SrO/Si sample using transmission electron microscopy (TEM) revealed that the thickness of the SrO layer is less than 2 nm and that the SrRuO3 electrode forms an epitaxial thin film almost directly on Si.

We have investigated the effect of ozone on already existing silicon oxide films as preoxide on Si(100). The use of highly concentrated ozone (25 vol%) at atmospheric pressure has made it possible to modify a native oxide film on Si(100) at 350°C, resulting in upgraded film quality and reduced thickness of structural transition layers. This was shown by the change of an etching rate by hydrofluoric acid (HF) solution of the oxide film exposed to ozone. However, the exposure of ozone to Si(100) at 350°C with an already existing thermally grown oxide film caused no change in the distribution of transition layers in the oxide. This contrast suggests the possibility of upgrading the properties of a preoxide film without structural transition layers at the appropriate substrate temperature.

We have demonstrated the advanced highly scattering optical transmission (HSOT) polymer backlight that was designed by the HSOT designing simulation program. This backlight exhibited approximately three times higher luminance and 20% higher efficiency than the conventional flat-type HSOT backlight of 14.1-inch diagonal because of the microscopic prism structures at the bottom of the advanced HSOT light guide plate. The HSOT polymer containing the optimized heterogeneous structures produced homogeneous scattered light with forward directivity and sufficient color uniformity. Optimization of the heterogeneous structure is important in order to utilize the taper effect and the microscopic prism structures.

In this paper we describe the memory effect of vertically stacked InAs nanodots in the barrier layer of an Al0.5Ga0.5As/GaAs field-effect (FE) structure, by comparing this effect with that of single-layer InAs nanodots in the same FE structure. These FE structures are grown by molecular beam epitaxy, and Stranski-Krastanow islands are used for the InAs nanodots. The charge-storage effect of the nanodots is analyzed by capacitance–voltage (C–V) measurement and results in a hysteresis loop caused by stable electron trapping at nanodot potentials. The amount of "net" charge surviving at the stacked nanodots at 300 K is estimated to be ~ 14 nC/cm2, whereas that at the single-layer nanodots is nearly zero. These C–V characteristics are in good agreement with photoluminescence properties.

We report a new compact model for a ferroelectric-gate field-effect transistor (FeFET) considering multiple ferroelectric domain structures that can be thermally activated. The dynamics of the electric polarization and the thermal activation rate are calculated on the basis of the Landau–Khalatnikov (LK) theory. We implement this compact model in a circuit simulator, SmartSPICE, using Verilog-A language for analog circuit simulations. The device characteristics of FeFETs reported in experiments are well fitted by our compact model. We also perform the circuit simulation for the inverter utilizing FeFETs by using this compact model. Unlike normal inverters composed of MOSFETs, the switching speed of the inverter changes with the voltage pulse before the operation.

Authors propose the use of an ultrasonic transducer to achieve a passive safety system for a collision using a corner sensor. However, the sensitivity of the transducer decreases owing to Doppler shift in the case of a travelling car. On the contrary, authors also propose a resonance control method for the transducer using a generalized impedance converter (GIC) circuit. In this study, the resonance control frequency method is used to correct the sensitivity of the transducer. In the sensitivity control, the input impedance control of the GIC circuit is tried using a voltage-controlled resistance. The automatic sensitivity correction control is expected to be realized by a combination of the GIC circuit and frequency–voltage (F/V) converter. As a result, the sensitivity of a Langevin transducer with a GIC circuit as a receiver is slightly improved, compared with that of a retailed transducer. Moreover, the resonance frequency of the transducer can be controlled in the range of about 3 kHz using the GIC circuit and F/V converter.