Thermal Degradation Under Pulse Operation in Low-Temperature p-Channel Poly-Si Thin-Film Transistors

We analyzed the heat generation of a low-temperature polycrystalline thin-film transistor in pulse operation and proposed a technique for accurately measuring its thermal temperature in high-frequency operation. From this measurement, we were able to calculate the time constants for heating and radiation for the first time. At a low frequency, the temperature difference between when the pulse was on and off was remarkable. As the frequency was increased, the maximum and minimum temperatures approached each other and became equal at a frequency of approximately 1 kHz. We also measured the degradation in pulse operation and discussed the relationship between the thermal temperature and the degradation in the pulse operation     

A Broadcasting Scheme Considering Units to Play Continuous Media Data

Due to the recent proliferation of digital broadcasting systems, various schemes for broadcasting continuous media data such as music or movies have been studied. In general broadcasting systems, since clients have to wait until their desired data are broadcast, these schemes reduce the waiting time by dividing the data into several segments of equal size. However, continuous media data often have units for playing portions of the data. For example, data encoded by MPEG2 can be played every GOP (group of pictures). In this paper, we propose a scheme to reduce the waiting time considering the units. Our proposed scheme divides a continuous media data at every unit. By scheduling divided data so that clients finish receiving a unit before starting to play the unit, waiting time is effectively reduced.     

A lossless handover method for video transmission in mobile ATMnetworks and its subjective quality assessment

Cell loss is one of the major causes of degradation in quality of service in ATM mobile communication systems. It can be suppressed by employing buffer memories in the network; however, cell delay occurs as a consequence. This article proposes a lossless handover method for mobile ATM communication networks that both prevents cell loss and can suppress cell delay variation. The method was simulated on an experimental system to subjectively evaluate MPEG2 images relative to buffer memory size and the results obtained are presented     

On the efficiency of cautious schedulers for database concurrency control—Why insist on two-phase locking?

Thecautious scheduler, recently proposed for the concurrency control of database systems, never resorts to abortions or rollbacks for the purpose of concurrency control. The comprehensive performance evaluation study among different cautious schedulers and conventional non-cautious schedulers, however, has not yet been attempted. In this paper, we consider five scheduling algorithms and investigate their performance by means of simulation studies. Two of these algorithms are non-cautious; that is, thetwo-phase locking algorithm (2PL) (the most popular transaction scheduling algorithm in practical systems) and theconflict serializable algorithm (CSR) (a typical scheduling algorithm among those not using a locking mechanism; also calledD-serializable algorithm, conflict preserving serializable algorithm, orWW-serializable algorithm). The others are cautious scheduling algorithms modified from the above2PL andCSR; that is,cautious two-phase locking algorithm (C2PL), exclusive preclaimed two-phase locking algorithm (EP2PL), andcautious conflict serializable algoritm (CCSR). The results demonstrate the superiority of the cautious conflict serializable algorithm over the conventional two-phase locking algorithm, especially in the on-line system environment.This work was supported in part by the Ministry of Education, Science and Culture of Japan under Scientific Research Grant-in-Aid and in part by the Advancd Systems Foundations of British Columbia, Canada.     

Mixed powder coating film using thermoplastic polyester and its alkaline resistance

To improve alkaline resistance, a newly mixed powder coating film using thermoplastic polyethylene terephthalate (PET) was investigated. Two kinds of polyvinyl butyral (PVB) and two kinds of polyamide (PA) were chosen as the secondary polymer. The melting temperatures (T _ms) of these materials were lower than that of primary PET polymer so the mixed powder coating was able to form a dual phase film through a fluidized bed coating process. Microscope and Fourier transform infrared spectroscopy (FTIR) observations revealed that the dual phase structure was indeed successfully formed and there was a secondary layer over the entire surface area of the film. This mixed powder coating film significantly enhanced the alkaline resistance to an environment filled with NaOH solution at 40°C in which a secondary material would be effective in protecting the film. With regard to both alkaline resistance and film formability, PET/PVB was superior to the PET/PA mixture.     

Current reliability issues and future technologies for systems on silicon – processes, circuits, chip architecture, and design

The progress of silicon technology is opening the era of “systems on silicon” in which a large-scale memory, a CPU, and other logic macros will be integrated on a single chip. These kinds of chips, called system LSIs, have an especially promising future in mobile and multimedia applications but face inherent technical problems related to the reliability of ultrathin oxide film, conflict in the processing of different components, increased gate and subthreshold leakage currents, memory bottlenecks, and design complexity. This paper reviews the system LSIs and then introduces related technologies in processing, circuits, chip architecture, and design. It also discusses the influence of the system LSIs on business strategies.     

Experimental study of the flow in helical circular pipes: Torsion effect on the flow velocity and turbulence

An objective of the present paper is to experimentally clarify the torsion effect on the flow in helical circular pipes. We have made six helical circular pipes having different pitches and common non-dimensional curvature δ of about 0.1. The torsion parameter β0, which is defined by β0 = τ/（2δ）1/2 with non-dimensional torsion r, are taken to be 0.02, 0.45, 0.69, 1.01, 1.38 and 1.89 covering from small to very large pitch. The velocity distributions and the turbulence of the flow are measured using an X-type hot-wire anemometer in the range of the Reynolds number from 200 to 20000. The results obtained are summarized as follows： The mean secondary flow pattern in a cross section of the pipe changes from an ordinary twin-vortex type as is seen in a curved pipe without torsion （toroidal pipe） to a single vortex type after one of the twin-vortex gradually disappears as β0 increases. The circulation direction of the single vortex is the same as the direction of torsion of the pipe. The mean velocity distribution of the axial flow is similar to that of the toroidal pipe at small β0, but changes its shape as β0 increases, and attains the shape similar to that in a straight circular pipe when ,β0 = 1.89. It is also found that the critical Reynolds number, at which the flow shows a marginal behavior to turbulence, decreases as ,β0 increases for small ,β0, and then increases after taking a minimum at ,β0 ≈ 1.4 as ,β0 increases. The minimum of the critical Reynolds number experimentally obtained is about 400 at ,β0 ≈ 1.4.     

Rheological properties of ethylene ionomer neutralized with binary metal cation

The roles of ionic bonding in molten ethylene ionomers without ionic aggregates were rheologically characterized in linear regions under shear. We have measured melt viscosities of ethylene-methacrylic acid (EMAA) ionomers by means of dynamic shear experiment. The samples used in this study were binary mixtures selected from Na, Mg and Zn salts of EMAA (MAA=5.4 mol%). The dynamic shear properties revealed that the time-material superposition is applicable to these ionomer blends in a temperature range from 140 to 200 °C. It was also found that these binary mixtures unexpectedly give decreases of zero shear viscosities obtained from a time-material superposition, if the cations were selected from different metal groups such as alkali, alkaline earth and transition metals. This behavior can be explained by the acid-cation exchange mechanism.     

Condensation enhancement on a vertical plate (1st report,heat transfer characteristic on a dispersed finned surface)

In this study, a condensation heat transfer experiment on vertical continuous and dispersed finned surfaces using FC5312 was carried out. Experimental parameters were the pitch and height of the fin, and the dispersed fin length. In the results, the phenomena of condensate retention were observed in the bottom of each row of the dispersed fin. The condensate flow from the upper row was concentrated into the valley of the fin and then flowed down into the valley of the next fin. Moreover, it was found from the experiment that the heat transfer coefficient on the dispersed finned surface was lower than the one on the continuous finned surface as the fin pitch was smaller, but was larger than that of the continued finned surface for a larger fin pitch. Furthermore, the heat transfer enhancing effect became more significant for the higher fin with the larger fin pitch, and the heat transfer reducing effect became more significant for the lower fin with the smaller fin pitch. These special characteristics of condensation mentioned above were caused by the phenomena of condensate retention in each row of the fin and the flow pattern of the condensate between two adjacent fins on the dispersed finned surface based on experimental observations. © 2008 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20221     

Effects of low- or medium-pressure ultraviolet lamp irradiation on Microcystis aeruginosa and Anabaena variabilis

A pure culture of Microcystis aeruginosa or Anabaena variabilis, the representatives of water blooming algae, was exposed to low-pressure (LP) or medium-pressure (MP) UV lamps. Irradiated pure culture suspension was subsequently incubated for 7d under white light fluorescent lamps. During incubation, profiles of the number of cells, DNA damage and photosynthetic activity were determined. When UV fluence was 600mJ/cm(2), M. aeruginosa cell numbers decreased throughout the 7-d incubation period, to produce 1.5log reduction (LP) or 1.2log reduction (MP) compared with control. The amount of DNA damage was 2.02x10(-4) ESS/base (LP) and 3.42x10(-4) ESS/base (MP) just after UV irradiation, which became 0.05x10(-4) ESS/base and 0.23x10(-4) ESS/base, respectively, after 3d incubation. However, cell number kept decreasing, even after DNA repair. Photosynthetic activity decreased by 1.5log within 1d (LP) or 3d (MP). Thus, reduction in photosynthetic activity could contribute to the reduction in M. aeruginosa cell numbers. A. variabilis cell numbers reduced by 2.3log (LP) or 2.2log (MP) during the 7-d incubation period; however, after DNA damage repair, cell number began to increase. The amount of DNA damage was 6.07x10(-4) ESS/base (LP) and 4.48x10(-4) ESS/base (MP) just after UV irradiation, which became 0.23x10(-4) ESS/base and 0.40x10(-4) ESS/base, respectively, after 3d incubation. No reduction was observed in photosynthetic activity/cell. Therefore, DNA damage is the main contributor of the reduction in cell number of A. variabilis.