High brightness and reliable AlGaInP-based light-emitting diode for POF data links

High brightness and reliability operation ring light-emitting diode (LED) is fabricated for plastic optical fiber (POF) link using the distributed Bragg reflector (DBR) mirror and antireflection (AR) coating. The ring LED exhibited optical output as high as 3.5 mW at the bias current of 100 mA. Furthermore, the projection lifetime is also estimated to be 1/spl times/10/sup 6/ h at a 35-mA data-link operating current and ambient temperature of 60/spl deg/C.     

Properties of the peptides liberated from rice protein in sokujo-moto

In the supernatant of sokujo-moto, a high level of acid carboxypeptidase (ACP) activity and a large amount of peptides were observed, however, the amount of free amino acids liberated was small. In order to determine why these peptides were not hydrolyzed to any significant degree by the ACP, the properties of the peptides in sokujo-moto were investigated in this study. Peptides were fractionated from sokujo-moto by ion exchange column chromatography. ACP purified from rice-koji (rice overgrown with Aspergillus oryzae) was allowed to react with the peptides, and it was found that they were not hydrolyzed to any significant degree by the enzyme. Gel filtration chromatography was performed to ascertain the molecular size distribution of the peptides in sokujo-moto, and it was revealed that they were of low molecular sizes; molecular size: mainly in the range of 200-400, and chain length: 2-3. ACP purified from rice-koji was also allowed to react with various synthetic peptides, and it was found that ACP of rice-koji could not rapidly hydrolyze low-molecular-size peptides, such as dipeptides or tripeptides. Acid protease (AP) purified from rice-koji released peptides of molecular sizes mainly in the range of 300-600 or above from rice protein under acidic conditions (pH 3.6; the pH of sokujomoto). When AP and ACP were allowed to act at the same time on rice protein, mainly low-molecular-size peptides (molecular sizes mainly in the range of 200-400) were produced. From these results, it was estimated that AP released peptides with molecular sizes mainly in the range of 300-600 or above from rice protein and ACP degraded the relatively higher molecular size peptides among them to lower molecular size peptides; consequently only low-molecular-size peptides with molecular sizes mainly in the range of 200-400 were released in the supernatant of sokujo-moto.     

Myofibril-Bound Serine Proteinase (MBP) and its Degradation of Myofibrillar Proteins

Proteolysis of a myofibril-bound serine proteinase (MBP) from carp Cyprinus carpio on myofibrillar proteins and their gel formation ability were investigated. MBP readily decomposed myosin heavy chain as indicated by SDS-PAGE. In the preparation of kamaboko, the gel formation ability was diminished by addition of MBP. The optimum degradation temperatures of MBP to myosin heavy chain in myofibril and kamaboko gel were 55°C and 60°C, respectively. The degradation effects of MBP on actin, α-actinin and tropomyosin were studied by the immunoblotting method. Because of its myofibril-bound and myofibrillar protein degradation characteristics, MBP was regarded as the proteinase most probably involved in the modori effect.     

The use of caproic acid to prevent aerobic deterioration of silages after opening,with special reference to the amounts and time of application

The effectiveness of caproic acid (hexanoic acid) addition to silages prepared from Italian ryegrass or cocksfoot (dry matter 16.3–34.5%) in preventing aerobic deterioration after opening was investigated in five experiments with varying amounts and times of application. Silages prepared in PVC bag silos were transferred to expanded polystyrene containers and left in a room at 25°C for 7 days with access to air. Aerobic deterioration was judged by rise in temperature, increase in pH and changes in the counts of yeasts and moulds. A low dry matter silage containing a fairly large amount of butyric acid was stable, and another low dry matter silage was relatively stable. Silages made from wilted grass deteriorated. Application of 50 mmol/kg grass at ensiling prevented deterioration in all cases. The effect was also observed with 50 mmol addition at opening, 10 mmol at ensiling and 10 mmol at opening in that order.     

Negative giant surface potential of vacuum-evaporated tris(7-propyl-8-hydroxyquinolinolato) aluminum(III) [Al(7-Prq)3] film

Negative giant surface potential was realized in a vacuum-evaporated film of tris(7-propyl-8-hydroxyquinolinolato) aluminum(III) [Al(7-Prq)₃]. Electroabsorption response of the film presented an inverted polarity to that of tris(8-hydroxyquinolinolato) aluminum (Alq₃), suggesting opposite noncentrosymmetry of molecular orientation. Asymmetric dice model with molecular geometric effect has been proposed, and propyl substitution at 7 position of the ligands was indicated to affects the molecular posture on the surface to invert the polarity of noncentrosymmetry. Our results opened a new possibility of controlling molecular orientation in a film for device applications.     

EACLE : Energy-Aware Clustering Scheme with Transmission Power Control for Sensor Networks

In this paper, we propose a new energy efficient clustering scheme with transmission power control named “EACLE” (Energy-Aware CLustering scheme with transmission power control for sEnsor networks) for wireless sensor networks, which are composed of the following three components; “EACLE clustering” is a distributed clustering method by means of transmission power control, “EACLE routing” builds a tree rooted at a sink node and sets the paths from sensor nodes taking energy saving into consideration, and “EACLE transmission timing control” changes the transmission timing with different levels of transmission power to avoid packet collisions and facilitates packet binding. With an indoor wireless channel model which we obtained from channel measurement campaigns in rooms and corridors and an energy consumption model which we obtained from a measurement of a chipset, we performed computer simulations to investigate the performance of EACLE in a realistic environment. Our simulation results indicate that EACLE outperforms a conventional scheme such as EAD (Energy-Aware Data-centric routing) in terms of communication success rate and energy consumption. Furthermore, we fully discuss the impact of transmission power and timing control on the performance of EACLE.     

Degradation evaluation of poly-Si TFTs by comparing normal and reverse characteristics and behavior analysis of hot-carrier degradation

We propose degradation evaluation of poly-Si TFTs by comparing normal and reverse characteristics. Since symmetrical normal and reverse characteristics indicate Joule-heating degradation whereas asymmetrical characteristics indicate hot-carrier degradation, they can be clearly and easily classified. Moreover, degradation occurrence is contrasted between standard and fine TFTs. Finally, behavior of the hot-carrier degradation is analyzed.     

New Paradigms in Wireless Communication Systems

This paper discusses what a new paradigm can be in wireless communication systems of the twenty-first century. First, it suggests two directions for the new paradigm; one is “micro- and nano-device communication system” which is the projected scenario considering that the entities in source and destination have been shrinking throughout the history of wireless communication systems. The second direction is “networked robot system”, which emerges as a natural extension of mobile ad hoc networking where the networking is closely related to motion control of robots. Secondly, it shows two interesting research topics, “the new communication protocol design” and “signal processing”, respectively, that arise in the wake of the fusion between the two directions in the novel communication paradigm. Finally, it considers a new science of wireless communications in the twenty-first century. Shinsuke Hara received the B.Eng., M.Eng. and Ph.D. degrees in communications engineering from Osaka University, Osaka, Japan, in 1985, 1987 and 1990, respectively. From April 1990 to March 1997, he was an assistant professor in the Department of Communication Engineering, School of Engineering, Osaka University, and from October 1997 to September 2005, he was an associate professor in the Department of Electronic, Information and Energy Engineering, Graduate School of Engineering, Osaka University. Since October 2005, he has been a professor in the Department of Physical Electronics and Informatics, Graduate School of Engineering, Osaka City University. In addition, from April 1995 to March 1996, he was a visiting scientist at Telecommunications and Traffic Control Systems Group, Delft University of Technology, Delft, The Netherlands. His research interests include wireless communications systems and digital signal processing. Hiroyuki Yomo received B.S. degree in communication engineering from Department of Communication Engineering, Osaka University, Osaka, Japan, in 1997, and M.S. and Ph.D. degrees in communication engineering from Department of Electronic, Information, and Energy Engineering, Graduate School of Engineering, Osaka University, Osaka Japan, in 1999 and 2002, respectively. From April 2002 to March 2004, he was a Post-doctoral Fellow in Department of Communication Technology, Aalborg University, Denmark. From April 2004 to September 2004, he was at Internet System Laboratory, NEC Corporation, Japan. Since October 2004, he has been an Assistant Research Professor in Center for TeleInfrastructure (CTIF), Aalborg University, Denmark. His main research interests are access technologies, radio resource management, and link-layer techniques in the area of short-range communication, cellular network, cognitive radio, and sensor network. Petar Popovski received the Dipl.-Ing. in electrical engineering and M.Sc. in communication engineering from the Faculty of Electrical Engineering, Sts. Cyril and Methodius University, Skopje, Republic of Macedonia, in 1997 and 2000, respectively. He received a Ph.D. degree from Aalborg University, Denmark, in 2004. From 1998 to 2001 he was a teaching and research assistant at the Institute of Telecommunications, Faculty of Electrical Engineering in Skopje. He is currently Assistant Professor at the Department of Communication Technology at the Aalborg University. His research interests are related to the PHY-MAC aspects of wireless protocols, wireless sensor networks, random access protocols, and network coding. Kazunori Hayashi received the B.E., M.E. and Ph.D. degrees in communication engineering from Osaka University, Osaka, Japan, in 1997, 1999 and 2002, respectively. He spent 3 months in 2000 at Aalborg University, Denmark, as a Visiting Scholar. Since 2002, he has been with the Department of Systems Science, Graduate School of Informatics, Kyoto University. He is currently an Assistant Professor there. His research interests include digital signal processing for communications systems.     

A 63-mW H.264/MPEG-4 audio/visual codec LSI with module-wise dynamic Voltage/frequency scaling

A single-chip H.264 and MPEG-4 audio-visual LSI for mobile applications including terrestrial digital broadcasting system (ISDB-T / DVB-H) with a module-wise, dynamic voltage/frequency scaling architecture is presented for the first time. This LSI can keep operating even during the voltage/frequency transition, so there is no performance overhead. It is realized through a dynamic deskewing system and an on-chip voltage regulator with slew rate control. By the combination with traditional low power techniques such as embedded DRAM and clock gating, it consumes only 63 mW in decoding QVGA H.264 video at 15 frames/sec and MPEG-4 AAC LC audio simultaneously.     

A 146-mm/sup 2/ 8-gb multi-level NAND flash memory with 70-nm CMOS technology

An 8-Gb multi-level NAND Flash memory with 4-level programmed cells has been developed successfully. The cost-effective small chip has been fabricated in 70-nm CMOS technology. To decrease the chip size, a one-sided pad arrangement with compacted core architecture and a block address expansion scheme without block redundancy replacement have been introduced. With these methods, the chip size has been reduced to 146 mm/sup 2/, which is 4.9% smaller than the conventional chip. In terms of performance, the program throughput reaches 6 MB/s at 4-KB page operation, which is significantly faster than previously reported and very competitive with binary Flash memories. This high performance has been achieved by the combination of the multi-level cell (MLC) programming with write caches and with the program voltage compensation technique for neighboring select transistors. The read throughput reaches 60 MB/s using 16I/O configuration.