TDMA-based adaptive modulation with dynamic channel assignment forhigh-capacity communication systems

This paper proposes a time-division multiple-access (TDMA)-based adaptive modulation scheme with dynamic channel assignment (AMDCA) to achieve high-capacity communication systems under dynamically changing propagation path and traffic conditions. The proposed method measures the received carrier-to-noise plus interference power ratio (C/(N+I)) of each TDMA slot to search available slots as well as to find out the optimum modulation parameters for each terminal, thereby effectively combining the effect of mitigating both spatially distributed electric field strength variation by the slow adaptive modulation and spatially and temporally distributed traffic variation by the dynamic channel assignment (DCA). Computer simulation confirms that the proposed AMDCA system can achieve approximately three times higher system capacity than the conventional fixed channel assignment (FCA) using QPSK     

Torque control strategy for a parallel-hybrid vehicle using fuzzy logic

In this article, we introduce a fuzzy logic controller to the driving strategy of a hybrid electric vehicle (HEV). The decision making of this fuzzy logic controller is useful to nonlinear and uncertain systems such as electric vehicle applications, and the fuzzy logic controller is immune to various vehicle load and road conditions. To construct the proper rule base of the fuzzy logic controller, the torque-producing, pollutant-emission, and fuel-consumption characteristics of the diesel engine and the hybrid system are clarified through dynamo testing. Then, the driving patterns of the driver and vehicle load on the service course are investigated. These results are also reflected in constructing the rule bases of the proposed fuzzy logic controller. To prove the usefulness of the proposed fuzzy logic controller, actual road tests of the parallel HEV are carried out. Note that the battery maintains its nominal voltage through 20 days of running without extra charging process.     

Ethyl cellulose films as alignment layers for liquid crystals

Films were formed by coating hydroxypropyl cellulose (HPC) or ethyl cellulose (EC) with different kinds of solvents at high coating speeds and thin coating thicknesses. These films were used as alignment layers for liquid crystals. Atomic force microscopy (AFM) and polarizing optical microscopy (POM) were used to identify the banded texture structure of the films. The alignments of a nematic liquid crystal 5CB droplet on those films were observed by POM. Further, a novel cycle disclination line was recorded and studied. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2770–2774, 2001     

Evaluation of radiation damaged p-in-n and n-in-n siliconmicrostrip detectors

Two p-in-n and one n-in-n silicon microstrip detectors were radiation-damaged and tested in a beam. A comparison was made between the p-in-n and the n-in-n in high resistivity wafers, and the p-in-n in a low and a high resistivity wafer. The charge collection showed a clear difference in the n-in-n and the p-in-n detectors, which suggested that the signals were shared between strips more in the irradiated p-in-n detectors. Although a difference of the low and the high resistivity wafers was observed in the body capacitance measurement, little difference was observed in the beam test results     

Electrochemical study of reversible hydrogenase reaction of Desulfovibrio vulgaris cells with methyl viologen as an electron carrier.

An electrode modified with immobilized whole cells of Desulfovibrio vulgaris (Hildenborough) produces an S-shaped voltammogram with both cathodic- and anodic-catalytic-limiting currents in a methyl viologen-containing buffer saturated with H2. Methyl viologen penetrates into the bacterial cells to serve as an electron carrier in the reversible reaction of hydrogenase in the cells and functions as an electron-transfer mediator between the bacterial cells and the electrode, thus producing the catalytic currents for the evolution and consumption of H2. An equation for the catalytic current that takes into account the reversible hydrogenase reaction explains well the shape of the voltammogram. The potential at null current on the voltammogram agrees with the potential determined by potentiometry with the same electrode, which is equal to the redox potential of the H+/H2 couple in the solution--the standard potential of a hydrogen electrode at the pH of the solution. When D. vulgaris cells are suspended in an argon-saturated buffer containing methyl viologen, the suspension produces a catalytic current at a bare glassy carbon electrode for the evolution of H2. Analysis of the current by a theory for a catalytic current for a unidirectional nonlinear enzyme catalysis allows us to determine the kinetic parameters of the reaction between methyl viologen and hydrogenase in intact D. vulgaris cells. Thus we obtain the apparent Michaelis constant for methyl viologen cation radical, K'MV.+ = 0.16 mM, and the apparent catalytic constant (that is, the turnover number per D. vulgaris cell), zkcat,H+ = 1.2 x 10(7) s-1, for the H2 evolution reaction at pH 5.5 and at 25 degrees C, z being the number of hydrogenases contained in a D. vulgaris cell. The bimolecular reaction rate constant, kcat,H+/K'MV.+, of the reaction between methyl viologen cation radical and oxidized hydrogenase in intact D. vulgaris cells is estimated as 4.2 x 10(7) M-1 s-1. Similarly, the bimolecular reaction rate constant, kcat,H2/K'MV2+, of the reaction between methyl viologen and reduced hydrogenase is estimated to be 1.2 x 10(7) M-1 s-1 at pH 9.5 and 25 degrees C. Both rate constants are large enough for the reactions to be diffusion-limited processes.     

Antineuronal antibodies in acute cerebellar ataxia following Epstein-Barr virus infection

A 29-year-old man developed acute cerebellar ataxia following Epstein-Barr virus infection. Serum IgG and IgM antibodies reacted with both nuclear and cytoplasmic elements of neurons. Western blot revealed IgG binding to the 34- and 29-kd bands and IgM binding to the 44-, 37-, and 29-kd bands. The IgM reactivity gradually reduced. There was no identifiable neoplasm and the ataxia gradually improved. These findings suggest a role for autoimmune mechanisms in the pathogenesis of acute cerebellar ataxia.     

Smoking cessation increases the resistance of low-density lipoprotein to oxidation

The effects of smoking cessation on the susceptibility to oxidation of low-density lipoprotein (LDL) was investigated in 14 men who quit smoking for 3 months. LDL was isolated and susceptibility of LDL to V-70 (4-methoxy-2,4-dimethylvalerinitrile)-mediated oxidation was assessed by measuring conjugated diene production at 234 nm, the lag phase being a measure of the resistance of LDL to oxidation. The mean duration of the lag phase became 1.9-fold longer after 3 months (P < 0.001). The result suggests that the increase in resistance of LDL to oxidation contributes to the reduction of the risk of coronary heart disease by smoking cessation.     

Inappropriate secretion of antidiuretic hormone (SIADH) in a patient with pleurisy related to adult onset Still''s disease

OBJECTIVE: To assess the prevalence of self-treatment in men with new episode non gonococcal urethritis (NGU). METHOD: Three hundred consecutive men with new episode NGU attending an open access genitourinary medicine clinic were interviewed using a semi-structured questionnaire. Details of treatment used before attending the clinic were obtained. RESULTS: Thirty (10%) men had used treatment, for an average of 7 days, prior to the clinic attendance. Agents used included antibiotics (11), savion or iodine (4), vitamin tablets (4), cisapride (2), local anaesthetic gel (2), antiseptic cream (2), cod liver oil (1), ferrous sulphate (1), naproxen (1), clotrimazole cream (1) and a poultice (1). Over 70% of the men reporting antibiotic use had self-medicated and in one case a fixed drug eruption had ensued. CONCLUSION: A significant number of men with NGU self-treat. In addition to the adverse effects of such treatment and the potential effect on culture tests, clinic attendance may be postponed, the use of appropriate therapy delayed, and sexual contacts will remain at risk. Early attendance for treatment and contact tracing is essential and should be actively promoted.     

Single wavelength grating filter laser array withGa0.3In0.7As/GaInAsP/InP strained MQW structure

Stable in-phase lateral- and single-longitudinal-mode operation up to four times the threshold (P_o~100 mW) was achieved in a five-element 1.5-μm-wavelength Ga_0.3In_0.7As/GaInAsP/InP compressive strained MQW grating filter laser array. The threshold current and external differential quantum efficiency under pulsed condition were 330 mA (emitter width of 18 μm, active region length of 480 μm) and 17%, respectively