In order to improve the running durability of organic electroluminescent devices (OELDs), the doping sites of molecular OELDs were optimized, and the frequency responses of the optimized devices were examined for Mg-In/bis (10-hydroxybenzo[h]quinolinate) beryllium (BeBq2)/N, N'-diphenyl-N, N'-(3-methylphenyl)-1, 1'-biphenyl-4, 4'-diamine (TPD)/4, 4', 4"-tris (3-methylphenylphenylamino) triphenylamine (MTDATA)/ITO. The TPD hole transport layer was the optimum doping site for 5, 6, 11, 12-tetraphenylnaphthacene (rubrene) dopant, and a very high efficiency of 13 cd/A at 0. 13 kcd/m2 was obtained for yellow emission. Half-decay times under a constant direct current density of 1. 0 mA/cm2 from an initial luminance of 0. 13 kcd/m2 extended to longer than 26,000 hours. The luminance of the optimized device decreases lineally with respect to the logarithm of the frequency as the frequency increases in the range from 1 kHz to 0. 3 MHz when a square wave with a duty ratio of 50% and a maximum voltage of 5.0 V is applied. A new driving method involving frequency modulation is proposed. This may offer accurate control of pixel luminance, and enable simple driving circuits adapted to highly integrated digital LSI chips, or the concept of system on glass.

Recently, wearable devices which use the human body as a transmission channel have been developed. However, there has been a lack of information related the transmission mechanism of such devices in the physical layer. Electro-magnetic communication trials using human body as transmission media have more than a decade's history. However, most of the researches have been conducted by researchers who just want to utilize the fact and practically no physical mechanisms have been researched until recently. Hence, in previous study, the authors proposed calculation models of the wearable transmitter and the receiver attached to the arm using the FDTD method. Moreover, the authors compared the calculated received signal levels to the measured ones by using a biological tissue-equivalent phantom. However, there was little analysis on each component of the propagated signal. In this paper, the authors clarified the transmission mechanism of the wearable device using the human body as a transmission channel from the view point of the interaction between electromagnetic wave and the human body. First, the authors focused their attention on measuring the each component of the propagated signal using a shielded loop antenna. From these results, the favorable direction of electrodes of the transmitter was proposed to use the human body as a transmission channel. As a result, longitudinal direction is effective for sending the signal to the receiver, compared to the transversal direction. Next, the authors investigated the dominant signal transmission channel, because the question of whether the dominant signal channel is in or around the arm had remained unsettled. To clear this question, the authors proposed the calculation model of an arm wearing the transmitter and receiver placed into a hole of a conductor plate. The electric field distribution and received signal voltage was investigated as a function of the gap between the hole of the conductor plate and the surface of the arm. The result indicated that the dominant signal transmission channel is not inside but the surface of the arm because signal seems to be distributed as a surface wave.

Newly designed cyclometalated iridium phosphors bearing 2,3-diphenylquinoxalines were characterized to provide highly efficient and vivid-red emitting materials for electrophosphorescent organic light-emitting devices. Excellent quantum efficiencies for photoluminescence (PL) within a range 50-79% were observed in dichloromethane solutions at room temperature. A greatly improved PL decay lifetime of 1.1 µsec was also observed in CBP coevaporated film. Luminescence peak wavelengths of the phosphors lay within a preferable range 653-675 nm in evaporated films. The most vivid-red electroluminescence with 1931 CIE chromaticity coordinates of (x=0.70, y=0.28) was successfully attained.

We propose a sea surveillance system that automatically detects intruding objects in the sea. The difficulty with an automatic system is detecting objects such as moving boats while reducing false positives caused by some waves and reflections in the sea. A false positive is reporting an object which doesn't actually exist, while a false negative is a failure in detecting an intruding object. Firstly, we identify factors of false positives. Secondly, we propose a new surveillance system considering these factors. Our proposed system combines three detecting methods. The first method is detection of Differences between Surveillance images and Flapping Reference images (DSFR). The second method is detection of Contours from Averaging images (CA). The third method is Silhouette object Detection (SD). The combination of DSFR and CA detects various moving objects under normal light conditions, while SD detects objects under backlight conditions. Finally we apply our proposed method to actual situations. Our proposed method detected boats while reducing false positives effectively.

A single-chip GaAs Transmit/Receive (T/R)-MMIC front-end has been developed which is applicable to 1. 9-GHz personal communication terminals such as digital cordless phones. This chip is fabricated using a planar self-aligned gate FET useful for low-cost and high-volume production. The chip integrates RF front-end analog circuits a power amplifier, a T/R-switch, and a low-noise amplifier. Additionally integrated are a newly developed voltage-doubler negative-voltage generator (VDNVG) and a control logic circuit to control transmit and receive functions, enabling both a single-voltage operation and an enhanced power handling capability of the switch, even under a single low-voltage supply condition of 2 V. The power amplifier incorporated onto the chip is capable of delivering a 21 dBm output power at a 39% efficiency, and a 30 dB associated gain with a 2 V single power supply in the transmit mode. The gain and efficiency are higher than those of the previously reported amplifier operating with a 2 V single power supply. The VDNVG produces a step-up voltage of 2. 9 V as well as a negative voltage of -1. 8 V from a 2 V power supply, operating with a charge time of less than 0. 25 µs. The control logic circuit on the chip has a newly designed interface circuit utilizing the step-up voltage and negative voltage, thereby enabling the chip to handle high power outputs over 24 dBm with a low operating voltage of 2 V. In the receive mode, a 1. 7 dB noise figure and a 0. 6 dB insertion loss are achieved with a current dissipation of 3. 6 mA. The developed MMIC, which is the first reported 2 V single-voltage operation T/R-MMIC front-end, is expected to contribute to the size and weight reductions in personal communication terminals.

Open circuit voltage (OCV) of electrical devices is an issue in various fields, whose numerical evaluation needs careful treatment. The open-circuited structure is ill-conditioned because of the singular electric field at the corners, and the TEM component of the electric field has to be extracted before integrated to give the voltage in the direct method of obtaining the OCV. This paper introduces the indirect methods to calculate the OCV, the admittance matrix method and the Norton theorem method. Both methods are based on the short-circuited structure which is well-conditioned. The explicit expressions of the OCV are derived in terms of the admittance matrix elements in the admittance matrix method, and in terms of the short circuit current and the antenna impedance of the electrical device under consideration in the Norton theorem method. These two methods are equivalent in theory, but the admittance matrix method is suitable for the nearby transmitter cases while the Norton theorem method is suitable for the distant transmitter cases. Several examples are given to show the usefulness of the present theory.

The capacity (i.e., maximum flow) of a unicast network is known to be equal to the minimum s-t cut capacity due to the max-flow min-cut theorem. If the topology of a network (or link capacities) is dynamically changing or unknown, it is not so trivial to predict statistical properties on the maximum flow of the network. In this paper, we present a probabilistic analysis for evaluating the accumulate distribution of the minimum s-t cut capacity on random graphs. The graph ensemble treated in this paper consists of undirected graphs with arbitrary specified degree distribution. The main contribution of our work is a lower bound for the accumulate distribution of the minimum s-t cut capacity. The feature of our approach is to utilize the correspondence between the cut space of an undirected graph and a binary LDGM (low-density generator-matrix) code. From some computer experiments, it is observed that the lower bound derived here reflects the actual statistical behavior of the minimum s-t cut capacity of random graphs with specified degrees.