Photoemission Study of Perovskite-Type Manganites with Stripe Ordering

We have studied the chemical potential shift and changes in the electronic density of states near the Fermi level (E _F) as functions of temperature and carrier concentration in Pr_1−x Ca _x MnO₃ (PCMO) and Nd_1−x Sr _x MnO₃ (NSMO) by measurements of photoemission spectra. Suppression of the chemical potential shift as a function of carrier concentration has been observed in PCMO and NSMO near and in the composition range where the CE-type antiferromagnetic charge-ordered (CO) phase appears at low temperatures. This result indicates that there is charge self-organization on a microscopic scale such as stripe formation in this composition range. In the ferromagnetic metallic phase of NSMO, we found a large temperature-dependent chemical potential shift at low temperatures and attributed this to double-exchange mechanism. Suppression of the temperature-dependent chemical potential shift near Curie temperature was observed, possibly associated with the formation of correlated polarons. In the valence band near the E _F of PCMO, spectral weight was transferred with hole doping, leading to a finite intensity at E _F even in the paramagnetic insulating phase above the CO phase for x≳0.3, and as the temperature was lowered, a clear gap opening was observed in the CO phase.     

Examining efficient instructional methods for computer-aided brush coating skill training system in elementary and secondary education

In recent Japan, many elementary and secondary school children strongly feel an awareness of resistance toward manufacturing class. It is considered as one of the aversion causes to science and engineering. We suspect that the shortage of teacher’s manufacturing experience is related to this background. So, the authors previously have developed a brush coating skill training system with a haptic device to improve the ability. In the skill training, historically, the instruction method while reproducing the video of trainee’s action has been considered to be effective. Thus, our developed system includes a software system to visualize the brush coating motion. This software system can record trainee’s brush coating motion and visualize the data in virtual three-dimensional space, so the advisor and the trainee can share his/her skill level and the wrong motion such as extra shaking and tilt by reproducing his/her past training data on a computer screen. In this paper, to improve the learning effectiveness of our brush coating skill training system, some kinds of instructional methods are designed, and the difference of the instructional methods is analyzed based on the proposed criteria. This paper performed some experiments with 10 college students who have less experience of brush coating. From the analysis results, the most effective instruction method was clarified.     

Stability Analysis of Linear Shift‐Invariant Dynamics in Honeycomb Structure

This paper deals with the stability of linear shift‐invariant multidimensional dynamical systems defined on honeycomb structure. Two different honeycomb structures are discussed. The local dynamical states are assumed to be distributed to honeycomb cells in the first consideration, and they are assumed to be distributed to the nodes of honeycomb mesh in the second consideration. In each honeycomb structure, the fundamental linear shift‐invariant dynamics is introduced and then the stability criterion is presented.     

Impact charging of particulate materials

When a particle impacts on a wall, electrostatic charges may be generated. This is called contact/impact/frictional electrification. One question to be answered is how and what process dominate the amount of the charge. In this respect, the separating process, rather than the contacting one, is important. It is shown that the potential difference between the surfaces can increase so rapidly in the separation process that it can cause gas discharge. Once such a gas discharge takes place, the charge on each surface can relax on the path: the amount of charge after the separation is a kind of residual charge after the charge relaxation. This process has been modeled and the model is called the “charge relaxation model.” It can estimate the amount of the impact charge without any empirical parameters, although the gas discharge itself is only an assumption so far which has not been directly observed or confirmed experimentally. In the experimental aspect, an “impact charging experiment” with single particles was carried out to provide a basis for the fundamental discussions. Polymer as well as metal particles about 3 mm in diameter ones were initially used, and the results showed good agreement with the “charge relaxation model.” The sensitivity of the instrument was enhanced to allow measurements with micrometer particles. These results are also reviewed here.     

OC-192 transmitter and receiver in standard 0.18-/spl mu/m CMOS

This paper presents the first fully integrated SONET OC-192 transmitter and receiver fabricated in a standard 0.18-/spl mu/m CMOS process. The transmitter consists of an input data register, 16-b-wide first-in-first-out (FIFO) circuit, clock multiplier unit (CMU), and 16:1 multiplexer to give a 10-Gb/s serial output. The receiver integrates an input amplifier for 10-Gb/s data, clock and data recovery circuit (CDR), 1:16 demultiplexer, and drivers for low-voltage differential signal (LVDS) outputs. An on-chip LC-type voltage-controlled oscillator (VCO) is employed by both the transmitter and receiver. The chipset operates at multiple data rates (9.95-10.71 Gb/s) with functionality compatible with the multisource agreement (MSA) for 10-Gb transponders. Both chips demonstrate SONET-compliant jitter characteristics. The transmitter 10.66-GHz output clock jitter is 0.065 UI/sub pp/ (unit interval, peak-to-peak) over a 50-kHz-80-MHz bandwidth. The receiver jitter tolerance is more than 0.4 UI/sub pp/ at high frequencies (4-80 MHz). A high level of integration and low-power consumption is achieved by using a standard CMOS process. The transmitter and receiver dissipate a total power of 1.32 W at 1.8 V and are packaged in a plastic ball grid array with a footprint of 11/spl times/11 mm/sup 2/.     

Flame stabilization and emission of small Swiss-roll combustors as heaters

The characteristics of small Swiss-roll combustors were investigated experimentally in detail. Three types of Swiss-roll combustors of different designs and two cases of heat transfer conditions were studied. The effects of design parameters on the performance of these combustors were examined. Each combustor consisted of a combustion region at the center (called the combustion room) and double spiral-shaped channels, the widths of which were smaller than the minimum quenching distance of a propane premixed flame at a normal state. Flames could be stabilized successfully for a wide range of equivalence ratios and mean velocities by using the recirculated heat from the burned gas, and blow-off was not observed. Temperature distributions of the combustors, variation of gas temperature, and the concentrations of the exhaust gas from the combustors were also investigated. Mean temperatures of the combustors were found to be governed by both the radiant heat loss from the combustors and the total chemical energy liberated by the combustors. Efficiencies of the combustors as heaters were evaluated. As a combustor became smaller, its thermal efficiency as a heater increased and its NO_x emission decreased, while the emission of CO increased. By adding a catalytic reactor at the exhaust port, it was found that the emission of CO could be eliminated. This study provides new experimental results for a small Swiss-roll combustor, which represents an essential step toward the development of a microcombustor.