Schottky barrier heights of contact metals to p-type ZnSe

Schottky barrier heights (SBHs) of a variety of metals (In, Cd, Nb, Ti, W, Cu, Ag, Au, Ni, Pt, and Se) contacting to p-ZnSe grown by a molecular beam epitaxy method were determined by analyzing capacitance-voltage (C-V) and/or current density-voltage (J-V) curves. The SBH values of the Au and Ni contacts were determined from intersections of straight lines of the C⁻²-V curves to be 1.23 and 1.13 eV, respectively. The J-V calculations provided a large SBH value of 1.2 ± 0.1 eV for a variety of metals, indicating that the Fermi-level could be pinned at the contact interface. Reduction of the SBH values to a level lower than 0.4 eV and/or increase of doping concentrations to a level higher than 10²⁰ cm⁻³ are essential to obtain an ohmic contact with contact resistivity of around 10⁻³ Ω·cm².     

Is it possible to differentiate between choledochal cyst and congenital biliary atresia (type I cyst) by antenatal ultrasonography?

Both choledochal cyst and congenital biliary atresia (type I cyst) may share the same ultrasonographic pattern. We report 2 cases which were shown to have cystic structures on the upper abdomen by antenatal ultrasonography. The size of the choledochal cyst found at 24 weeks' gestation increased steadily as gestational age advanced. But the size of the cyst in congenital biliary atresia found at 29 weeks' gestation remained unchanged throughout the remaining pregnancy. Cyst enlargement, therefore, may suggest the possibility of a choledochal cyst.     

Study of sexual function in male hemodialysis patients--a sexual function survey using a questionnaire

Sexual dysfunction is a well-documented complication among male hemodialysis patients. To evaluate it in detail, we conducted a sexual function survey using the Sapporo Medical University Sexual Function Questionnaire. Two hundred five male patients receiving outpatient hemodialysis were entered into this study. Patients with diabetes mellitus and severe anemia (Hb value < 8.0 g/dl) were excluded. The control group consisted of 3,462 healthy male subjects. Of male hemodialysis patients, 33.7% showed deterioration of libido, while 44.4% showed deterioration of potency, both of them decreased greatly with age. Ejaculatory ability correlated with potency. We compared the frequency of sexual intercourse in male hemodialysis patients with that in normal males. Twelve point nine percent of hemodialysis patients (HP) ranging from 30 to 39 in age versus 3.5% of age-matched normal males had no sexual intercourse and 22.4% of HPs from 40 to 49 versus 3.0% of age-matched normal males, 52.2% of HPs from 50 to 59 versus 7.5% of age-matched normal males, and 89.3% of HPs from 60 to 69 versus 18.0% of age-matched normal males had no sexual intercourse. These results revealed that the sexual frequency in hemodialysis patients decreased more than that in normal males in all age groups and with age.     

Assignment of most genes encoding major peroxisomal polypeptides to chromosomal band V of the asporogenic yeast Candida tropicalis

The peroxisomes of the asporogenic yeast Candida tropicalis contain about 20 major polypeptides (PXPs). We have isolated a number of genes encoding them; 11 POX genes encoded independent PXPs and three POY genes were likely to encode three other PXPs. To locate these genes on the chromosomes, chromosomes of C. tropicalis were separated by pulsed-field gel electrophoresis. Eight chromosomal bands were observed over the range of 1.0 Mbp (band 1) to 2.8 Mbp (band VIII); the genome size was estimated to be about 20 Mbp. Southern blot analysis showed that ten genes were on band V, three genes were on band IV, and the other gene was on band VI. Three genes gave hybridization signals of nearly equal intensity on two different chromosomal bands: POX6A and POX8B, on bands V and VII; and POX8A, on bands IV and VI. Ribosomal RNA genes also hybridized to two bands, VI and VII. Most genes assigned to only one band hybridized to two restriction fragments produced by either NotI or SfiI endonuclease. The results suggested that C. tropicalis was diploid and that restriction sites were conserved little between homologues. The three POX genes that were found on two chromosomal bands hybridized to not more than two restriction fragments, implying that the allelic genes were present on different chromosomal bands.     

Hydroliquefaction of low-sulfur coals using iron carbonyl complexes—Sulfur as catalysts

Hydroliquefaction of low-sulfur Australian coals (Wandoan and Yallourn) was studied using iron carbonyl complexes as catalyst. The addition of Fe(CO)₅ (2.8 wt% Fe of coal) increased coal conversion from 48.6 to 85.2% for Wandoan coal, and from 36.7 to 69.7% for Yallourn coal in 1-methylnaphthalene at 425°C under an initial hydrogen pressure of 50 kg cm^?2. When molecular sulfur was added to iron carbonyls (Fe(CO)₅, Fe₂(CO)₉ and Fe₃(CO)₁₂), higher coal converions ( > 92%) and higher oil yields (>46%) were obtained, along with an increase in the amount of hydrogen transferred to coal from the gas phase (0.2 to 2.8%, d.a.f. coal basis). In the liquefaction studies using a hydrogen donor solvent, tetralin, Fe(CO)₅S catalyst increased the amount of hydrogen absorbed from the gaseous phase and decreased the amount of naphthalene dehydrogenated from tetralin. The direct hydrogen transfer reaction from molecular hydrogen to coal fragment radicals seems to be a major reaction pathway. Organic sulfur compounds, dimethyldisulfide and benzothiophene, and inorganic FeS₂ and NiS were found to be good sulfur sources to Fe(CO)₅. From X-ray diffraction analyses of liquefaction residues, it is concluded that Fe(CO)₅ was converted into pyrrhotite (Fe_1?xS) when sulfur was present, but into Fe₃O₄ in the absence of sulfur.     

Generation of adaptive gait patterns for quadruped robot with CPG network including motor dynamic model

This paper describes the generation of adaptive gait patterns using new Central Pattern Generators (CPGs) including motor dynamic models for a quadruped robot under various environments. The CPGs act as the flexible oscillators of the joints and adjust joint angles to required values. The CPGs are interconnected with each other and sets of their coupling parameters are adjusted by a genetic algorithm so that the quadruped robot can realize stable and adequate gait patterns. Generation of gait patterns results in the formation of the CPG networks suitable for the formation of not only a straight walking pattern but also of rotating gait patterns. Experimental results demonstrate that the proposed CPG networks are effective for the automatic adjustment of the adaptive gait patterns for the tested quadruped robot under various environments. Furthermore, the target tracking control based on image processing is achieved by combining the general gait patterns. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(1): 35–43, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20225     

A 220-MHz pipelined 16-Mb BiCMOS SRAM with PLL proportionalself-timing generator

This 512 Kw×8 b×3 way synchronous BiCMOS SRAM uses a 2-stage wave-pipeline scheme, a PLL self-timing generator and a 0.4-μm BiCMOS process to achieve 220 MHz fully-random read/write operations with a GTL I/O interface. Newly developed circuit technologies include: 1) a zig-zag double word-line scheme, 2) a centered bit-line load layout scheme, and 3) a phase-locked-loop (PLL) with a multistage-tapped ring oscillator which generates a clock cycle proportional pulse (CCPP) and a clock edge lookahead pulse (CELP)     

Direct observation of time-dependent space charge profiles in XLPEcable under high electric fields

Space charge distribution was measured, applying an electric field of >1 MV/cm to 3 mm thick XLPE cable insulation. Improving the conventional pulse electro-acoustic method, a new method was developed to measure space charge when applying HV to cables. Under high field, hetero charges were formed soon after voltage application, followed by an injection from the cathode. Then intermittent injections of charge packets from the anode took place. The space charge distribution kept changing without becoming stabilized. A simulation was done assuming hysteresis of the injection characteristics. The observed intermittent injection near the anode was qualitatively reproduced using computer simulation     

Mean molal activity coefficients of aqueous scandium chloride, nitrate, bromide and perchlorate solutions at 25.0°

The mean molal activity coefficients of aqueous scandium chloride, nitrate, bromide and perchlorate solutions were determined at 25.0° for dilute to saturated concentrations, together with the activities of water. In the dilute solutions of scandium halides, the activity coefficients were obtained from electromotive force measurements on galvanic cells, and the osmotic coefficients of all four solutions above 0.1 mol kg⁻¹ were determined from the isopiestic measurements. Least-squares equations were fitted to these coefficients, which were then used to calculate the mean molal activity coefficients and water activities. The relationships between these results and the corresponding activity data for other rare earth salts, and to the cation hydration and ionic interactions, are discussed. The results on scandium perchlorate solutions suggested that the inner-sphere hydration number of tervalent scandium ion may be seven.