Effect of Elastic Energy due to Atomic Size Factor on Ordering and Decomposition Behaviour of Binary Solid Solutions

A theory recently developed by the present authors is applied to the study of the effect of elastic energy due to atomic size factor on the transformation behaviour of binary solid solutions. lt is found that elastic interaction energy (EIE), which is a part of the total elastic energy plays a key role in both ordering elastic interaction ordering (EIO) and spinodal decomposition. The present study gives a reasonable explanation to the historical dilemmas, "elastic energy paradox" and "atomic size factor paradox . By solving these confusing problems, the coexistence of ordering (EIO) and decomposition, which has been regarded as impossible by conventional theories. can be well understood. The mechanism is as follows: lowering of elastic energy demands EIO, and such an ordering provides a driving force for spinodal decomposition. Therefore, in alloys with large atomic size factor, spinodal decomposition is preceded and induced by ordering. Ordering and spinodal decomposition are thus closely related processes to each other     

Electrodeposition of mercury from the HgNO3-CH3OH-H2O system at low temperature

Peculiar dendritic deposits of mercury were obtained galvanostatically from the mercurous nitratemethanol-water system at –50° C. These deposits could not be maintained at a constant shape because, when the current was interrupted, they transformed and shrank immediately to a spherical shape with hydrogen evolution. It seems that when the electrical potential was removed, the mercury deposits liquefied and the hydrogen stored in them was released during the period of shrinking.     

Effect of water vapor and hydrocarbons in removing NOxby using nonthermal plasma and catalyst

Removal of NO_x in flue gas was investigated by using nonthermal plasma with catalysts. In this experiment, flue gas contained 5%-15% water vapor and hydrocarbons, as well as nitrogen, oxygen, and carbon dioxide. Catalysts tested in this paper were copper- and sodium-coated zeolite (CuZSM-5, NaZSM-5) and a conventional three-way catalyst (Pt-Rh, alumina cordierite). The simulated flue gases had from 0% to 15% water vapor, 70% NO removal was achieved with NaZSM-5 catalyst at 200°C-500°C, with 10% moisture and the power to the reactor turned off. High-temperature removal of NO_x was the result of plasma chemical reactions and adsorption in the catalyst. However, nonthermal plasma degrades the NO_x removal with CuZSM-5 catalyst, when the gas temperature is 300°C or above. When the gas temperature was 100°C, the nonthermal plasma process was enhanced by the combination of nonthermal plasma with any type of catalyst. The catalysts investigated in this paper do not work at lower temperatures by themselves. Adsorption characteristics were also investigated and only NaZSM-5 catalyst showed significant adsorption     

High-gain hybrid amplifier consisting of cascaded fluoride-based TDFA and silica-based EDFA in 1458-1540 nm wavelength region

A hybrid optical fibre amplifier is described that consists of a fluoride-based thulium-doped fibre amplifier and a silica-based erbium-doped fibre amplifier connected in a cascade. The amplifier has a gain of more than 25 dB and a noise figure of less than 9 dB over a wide wavelength region of 1458-1540 nm.     

Enhanced Hole‐Transporting Behavior of Discotic Liquid‐Crystalline Physical Gels

Discotic liquid‐crystalline (LC) physical gels have been prepared by combining the self‐assembled fibers of a low‐molecular‐weight gelator and semiconducting LC triphenylene derivatives. The hole mobilities of the discotic LC physical gels measured by a time‐of‐flight method become higher than those of LC triphenylenes alone. The introduction of the finely dispersed networks of the gelator in the hexagonal columnar phases may affect the molecular dynamics of the liquid crystals, resulting in the enhancement of hole transporting behavior in the LC gel state.     

Highly efficient configuration of a Pr3+-doped fluoridefiber amplifier module with an optical circulator

A highly efficient Pr³⁺-doped fluoride fiber amplifier configuration with an optical circulator, in which the input signal light is amplified both forward and backward through a Pr³⁺-doped fluoride fiber, is investigated with a view to decreasing the drive current and improving the reliability of pump laser diodes (LD's). With this double-path configuration, a 25-dB signal gain is achieved at an LD drive current of 110 mA. This LD drive current is about half that needed for a conventional single-path configuration. It is also found that this double-path configuration provides a double-gain coefficient, a slightly low saturation power, and a slightly narrow spectral gain width     

Temperature dependence of signal gain in Er3+-dopedoptical fiber amplifiers

Temperature-dependent signal gain characteristics at signal wavelengths of 1.536 and 1.552 μm in Er³⁺-doped optical fibers with a temperature range of -40 to 80°C are reported for 0.98 and 1.48 μm pumping. The temperature dependences of signal gain strongly depend on fiber length, pump wavelength, and signal wavelength. The fiber length at which signal gain temperature insensitivity occurs is found for the amplification of a 0.98-μm-pump-1.536-μm-signal, a 0.98-μm-pump-1.552-μm-signal, and a 1.48-μm-pump-1.536-μm-signal. It is confirmed theoretically that the temperature dependences result from linear changes in the fluorescence, and absorption cross sections at the signal and pump wavelengths, and a shift in the effective pump wavelength     

A 500-MHz 4-Mb CMOS pipeline-burst cache SRAM with point-to-pointnoise reduction coding I/O

A 32-b 500-MHz 4-1-1-1 operation 4-Mb pipeline burst cache SRAM has been developed. In order to achieve both high bandwidth operation and short latency operation, we developed the following technologies: 1) a prefetched pipeline-burst scheme with double late-write buffers, 2) gate size reduction and a bit-line equalization by source resetting, 3) point-to-point bidirectional coding I/O's to reduce bus noise and power consumption, and 4) a three-level metal 0.25-μm CMOS process technology with six transistor memory cells     

A side-wall transfer-transistor cell (SWATT cell) for highlyreliable multi-level NAND EEPROMs

A multi-level NAND Flash memory cell, using a new Side-WAll Transfer-Transistor (SWATT) structure, has been developed for a high performance and low bit cost Flash EEPROM. With the SWATT cell, a relatively wide threshold voltage (V_th) distribution of about 1.1 V is sufficient for a 4-level memory cell in contrast to a narrow 0.6 V distribution that is required for a conventional 4-level NAND cell. The key technology that allows this wide V_th distribution is the Transfer Transistor which is located at the side wall of the Shallow Trench Isolation (STI) region and is connected in parallel with the floating gate transistor. During read, the Transfer Transistors of the unselected cells (connected in series with the selected cell) function as pass transistors. So, even if the V_th of the unselected floating gate transistor is higher than the control gate voltage, the unselected cell will be in the ON state. As a result, the V_th distribution of the floating gate transistor can be wider and the programming can be faster because the number of program/verify cycles can be reduced. Furthermore, the SWATT cell results in a very small cell size of 0.57 μm² for a 0.35 μm rule. Thus, the SWATT cell combines a small cell size with a multi-level scheme to realize a very low bit cost. This paper describes the process technology and the device performance of the SWATT cell, which can be used to realize NAND EEPROM's of 512 Mbit and beyond     

A new write/erase method to improve the read disturbcharacteristics based on the decay phenomena of stress leakage currentfor flash memories

This paper describes a new write/erase method for flash memory to improve the read disturb characteristics by means of drastically reducing the stress leakage current in the tunnel oxide. This new write/erase operation method is based on the newly discovered three decay characteristics of the stress leakage current. The features of the proposed write/erase method are as follows: 1) the polarity of the additional pulse after applying write/erase pulse is the same as that of the control gate voltage in the read operation; 2) the voltage of the additional pulse is higher than that of a control gate in a read operation, and lower than that of a control gate in a write operation; and 3) an additional pulse is applied to the control gate just after a completion of the write/erase operation. With the proposed write/erase method, the degradation of the read disturb life time after 10⁶ write/erase cycles can be drastically reduced by 50% in comparison with the conventional bipolarity write/erase method used for NAND type flash memory. Furthermore, the degradation can he drastically reduced by 90% in comparison with the conventional unipolarity write/erase method fur NOR-, AND-, and DINOR-type flash memory. This proposed write/erase operation method has superior potential for applications to 256 Mb flash memories and beyond