A 5-GByte/s data-transfer scheme with bit-to-bit skew control forsynchronous DRAM

This paper describes a 5-GByte/s data-transfer scheme suitable for synchronous DRAM memory. To achieve a higher data-transfer frequency, the properties were improved based on the frequency analysis of the memory system. Then, a bit-to-bit skew compensation technique that eliminates incongruent skew between the signals is described with a new, multioutput controlled delay circuit to accomplish bit-to-bit skew compensation by controlling transmission timing of every data bit. Simulated maximum data-transfer rate of the proposed memory system resulted in 5.1/5.8 GByte/s (321/365 MHz, ×64 bit, double data rate) for data write/read operation, respectively     

Characteristics of transients among periodic attractors controlledby high-frequency injection in a chaotic laser diode

We numerically studied statistics of the transient response time when switching between periodic attractors obtained through chaos control with a high-frequency injection method in a laser diode that is subject to optical feedback. Each transient response time significantly depends on its position in the starting attractor, whereas the statistical distributions of the response times for many transients are determined almost entirely by the final attractor. The average transient response time is 40 times larger than the round time in the controlled periodic attractors. The transient response time is also strongly affected by the external cavity length. The shortest average transient response time is obtained at a minimum external cavity length and a zero phase difference between the laser field and the feedback light field     

Vapor phase nitration of benzene over solid acid catalysts IV. Nitration with nitric acid (3); supported sulfuric acid catalyst with co-feeding of a trace amount of sulfuric acid

In the vapor phase nitration of benzene with diluted nitric acid, we have succeeded in keeping a high nitration activity of the supported sulfuric acid catalyst for more than 2 months by co-feeding a trace amount of sulfuric acid (H₂SO₄/HNO₃ = 1/5000 (wt. ratio)). The results after 60 days on-stream over 10 wt.%–H₂SO₄/SiO₂ catalyst are as follows: yield of nitrobenzene (NB), 93% based on HNO₃; selectivity of NB, 97% based on HNO₃; productivity of NB (STY), 0.76 kg/kg cat h. These performances were demonstrated in bench scale experiments using molded silica or quartz supports. Finally, nitration reactions of toluene and chlorobenzene were conducted and compared with each other over several solid acid catalysts developed by us.     

NDE of degradation of thermal barrier coating by means of impedance spectroscopy

Nondestructive evaluation of thermal barrier coating (TBC) degradation during service operation has received a wide attention for service life prediction of advanced gas turbines. In this work, TBC on nickel base superalloy degraded at various degrees by thermal aging is investigated. Particularly, TBC and Metal–Chromium–Aluminum–Yttrium alloy (McrAlY) (M indicates iron (Fe), cobalt (Co), nickel (Ni) or these combinations) bond coating interface where a detrimental reaction takes place and forms various reaction products during thermal aging, is studied in detail. Formation kinetics and physical properties of the reaction layer are evaluated by means of Impedance Spectroscopy (IS). Specimens aged at higher temperature and a longer aging time shows larger impedance. The impedance behavior of TBC and bond coating is found to be markedly changed by the formation of the reaction layer. Physical properties and thickness of the reaction layer are evaluated using the change of the impedance. A mechanistic interpretation of the cause of change in the physical properties and IS behavior are described.     

Solubility of propylene in semicrystalline polypropylene

Gas solubilities and polymer swelling in propylene and semicrystalline polypropylene system at temperatures of 323.2 and 348.2 K and pressures up to propylene's vapor pressure were measured. Pressure, specific volume, and temperature (PVT) measurements of polypropylene were carried out at temperatures from 313 to 573 K and pressures up 200 MPa. Two kinds of polypropylenes, which had different stereoregularities, were used for both solubility and PVT measurements. The solubilities were correlated with the Sanchez–Lacombe equation of state (EOS) with temperature‐dependent binary interaction parameters to within 5% average relative percentage deviation. Swelling ratios estimated with Sanchez–Lacombe EOS coupled with optimized interaction parameters were 20% lower than the experimental values. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1134–1143, 2001     

Pollution control of actual flue gas using pulsed power at a thermal power plant

There are several important environmental problems in the world. One of them is acid rain caused by combustion flue gases from thermal power plants, factories, and automobiles. Different kinds of gas discharges, such as surface discharge, dc and ac corona discharge, silent discharge, and electron beam controlled discharge, have been studied for the removal of NO_x and SO₂ from flue gases. The recent development of repetitive pulsed power generators gives the pulsed steamer corona discharges a chance of success in the removal of NO_x and SO₂. In this paper, the experimental results of NO_x and SO₂ removal by a repetitive pulse power generator are described. The actual flue gas at a thermal power plant was used. It is shown that about 90% of the NO was removed at a flow rate of 0.8 liters/min and a repetition rate of 7 pps. © 2001 Scripta Technica, Electr Eng Jpn, 134(4): 28–35, 2001     

The possibility of an accidental scenario for marine transportation of fuel cell vehicle: Hydrogen releases from TPRD by radiant heat from lower deck

In case fires break out on the lower deck of a car carrier ship or a ferry, the fuel cell vehicles (FCVs) parked on the upper deck may be exposed to radiant heat from the lower deck. Assuming that the thermal pressure relief device (TPRD) of an FCV hydrogen cylinder is activated by the radiant heat without the presence of flames, hydrogen gas will be released by TPRD to form combustible air-fuel mixtures in the vicinity. To investigate the possibility of this accident scenario, the present study investigated the relationship between radiant heat and TPRD activation time and evaluated the possibility of radiant heat causing hydrogen releases by TPRD activation under the condition of deck temperature reaching the spontaneous ignition level of the tires and other automotive parts. It was found: a) the tires as well as polypropylene and other plastic parts underwent spontaneous ignition before TPRD was activated by radiant heat and b) when finally TPRD was activated, the hydrogen releases were rapidly burned by the flames of the tires and plastic parts on fire. Consequently it was concluded that the explosion of air-fuel mixtures assumed in the accident scenario does not occur in the real world.