Wideband and compact folded loop antenna

A simple and successful design method that yields a wideband and compact antenna without a ground plane is proposed. The antenna, referred to as the folded loop antenna, can, with the right parameters, achieve wideband characteristics. Calculated and measured results agree well and more than 50% bandwidth (return loss /spl les/-10 dB) is obtained.     

Development of new‐type outdoor termination using composite insulator with SF6 gas: Commercial use for 77‐kV transmission lines and development for 154‐kV XLPE cable

Recently, composite insulators have been increasingly employed mainly for economic reasons. We have developed a new type of outdoor termination using a composite insulator, which can be installed horizontally on a steel tower in order to reduce the construction cost. In this outdoor termination, SF₆ gas is filled in the composite insulator and a cold shrinkable premolded rubber unit is applied instead of the combined use of a rubber‐molded stress relief cone, epoxy resin insulator and spring unit. The application of the composite insulator, SF₆ gas and cold shrinkable premolded rubber unit reduces the total weight and makes it possible to install the termination horizontally on the tower. The new‐type outdoor termination for 77‐kV XLPE cable has already been applied in commercial use and enabled a reduction of the construction costs for power transmission lines. A 154‐kV new‐type outdoor termination has been developed and its initial electrical tests were successfully completed. This paper describes the design and performance of both 77‐kV and 154‐kV new‐type outdoor termination, and a follow‐up survey of the 77‐kV new termination in a commercial use. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(4): 18– 26, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20511     

Wordline voltage generating system for low-power low-voltage flashmemories

A low-power wordline voltage generating system is developed for low-voltage flash memories. The limit for the stand-by current including the operation current for the band-gap reference and the stand-by wordline voltage generator is discussed. The system was implemented on a 1.8-V 32-Mb flash memory fabricated with a 0.25-μm flash memory process and achieved with very low stand-by current of 2 μA typically, and high operating frequency of 25 MHz in read operation at 1.8 V. A low-voltage level shifter with high-speed switching is also proposed     

Torsional impact response of a penny-shaped interface crack in a layered composite

The torsional impact response of a penny-shaped interface crack in a layered composite is considered in this study. The geometry of the composite consists of two bonded dissimilar elastic layers which are sandwiched between two half-spaces made of a different material. Laplace and Hankel transforms are used to reduce the problem to the solution of a pair of dual integral equations. These equations are solved by using an integral transform technique and the result is expressed in terms of a Fredholm integral equation of the second kind. A numerical Laplace inversion routine is used to recover the time dependence of the solution. The dynamic stress intensity factor is determined and its dependence on time, the material properties and the geometry parameters is discussed.     

Involvement of the adrenal glands and testis in gap junction formation via testosterone within the male rat anterior pituitary gland

We investigated the influence of testicular and adrenal androgens on the presence of gap junctions between folliculo‐stellate cells in the anterior pituitary glands of 60‐day‐old Wistar‐Imamichi strain male rats. The animals were separated into six groups: Group A served as the controls and had free access to a normal diet and water, Group B was given a normal diet and 0.9% NaCl for their drinking water as the controls of adrenalectomized groups, Group C was castrated, Group D was adrenalectomized, Group E was both castrated and adrenalectomized, and Group F was also both castrated and adrenalectomized. In addition, the animals of Group F were administered a dose of testosterone that is known to produce high physiological levels of the hormones in plasma. Five rats from each group were sacrificed 1, 2, 3, 4, 5, 6, and 7 days after their respective operation, and the anterior pituitary glands were removed and prepared for observation by transmission electron microscopy. We quantified the number of follicles and gap junctions and calculated the rate of occurrence as the ratio of the number of gap junctions existing between folliculo‐stellate cells per intersected follicle profile. Simultaneous removal of adrenal glands with castration resulted in a significantly decrease in the number of gap junctions, whereas the administration of testosterone to these rats compensated for this change. These observations indicate that the preservation of gap junctions between folliculo‐stellate cells is mainly dependent on androgens from both the testes and adrenal glands in adult male rats. Microsc. Res. Tech., 2012. © 2012 Wiley Periodicals, Inc.     

Fischer–Tropsch synthesis in slurry-phase reactors over Mn- and Zr-modified Co/SiO2 catalysts

Fischer–Tropsch (F–T) synthesis was carried out in a gas-flowed slurry-phase reaction system over Mn- and Zr-modified Co/SiO₂ catalysts. A 0.5 L stirred tank slurry reactor (STSR) was used for catalyst screening and a 12.5 L slurry bubble column reactor (SBCR) was used for trial pilot operation. While using the 0.5 L reactor for catalyst screening, Co supported on the SiO₂ with an average pore size of 10 nm showed a high catalytic performance for the F–T synthesis due to the suitable Co particle size in the catalyst. Zr promoter improved the activity and Mn promoter improved the stability of Co/SiO₂ catalyst for the F–T synthesis. H₂-TPR profiles indicated that Zr and Mn promoters improved the reduction degree of Co₃O₄ particles (on SiO₂ surface) to Co⁰ active species in H₂ flow at low temperature. While using the 12.5 L reactor for trial pilot operation over Mn–Zr–Co/SiO₂ catalyst, the space-time yield (STY) of C₅₊ hydrocarbons (liquid fuel) showed almost the same values when various solvents (n-C₁₆H₃₄, n-C₁₄H₃₀, diesel from petrol station, F–T crude oil) were used. Diesel and F–T crude oil are suitable for using in a large-scaled F–T synthesis plant owing to the low prices. Mn–Zr–Co/SiO₂ catalyst achieved a STY of C₅₊ hydrocarbons larger than 1000 g-C₅₊ kg-cat^? 1 h^? 1 in the 12.5 L reactor. The production capacity of liquid fuel from the 12.5 L reactor reached to 15.6 L per day (assumed for 24 h continuous operation). The stirring was very important for the F–T synthesis both reaction in the 0.5 L reactor and reaction in the 12.5 L reactor. The shape of slurry reactor also influenced the CO conversion for the F–T synthesis: reaction in the 12.5 L SBCR gave a higher CO conversion than that of reaction in the 0.5 L STSR (at the same W/F value under the same stirring speed) because the slender column reactor (SBCR) extended the residue time of reaction gas in the slurry-phase containing catalyst.     

Fcgamma receptor IIA H/R131 polymorphism in patients with antiphospholipid antibodies

A role for Fcgamma receptor in the pathophysiology of thrombosis in APS has been hypothesized. The polymorphism of this receptor, FcgammaRIIA H/R131, is associated with the binding affinity for human IgG2 (i.e. FcgammaRIIA-H131 isoform has a higher affinity than FcgammaRIIA-R131). Since anti-beta2 glycoprotein I antibodies (anti beta2GPI), which play a major pathogenic role in APS, show IgG2 dominant distribution, we investigated the prevalence of receptor isoforms in patients with antiphospholipid antibodies (aPL) by a PCR-RFLP method. We studied 100 Caucasian patients with aPL (57 primary APS, 32 secondary APS to SLE and 11 other diseases with aPL) and 41 healthy controls. H131/H131, H131/R131 and R131/R131 genotypes were found in 21 (21%), 50 (50%) and 29 (29%) in the patient group, and 9 (22%), 23 (56%) and 9 (22%) in control group, respectively. Thus there was no statistically significant difference in the prevalence of each genotype in these groups. None of the clinical manifestations of primary APS (arterial/venous thrombosis, recurrent pregnancy loss and thrombocytopenia) was significantly correlated with any FcgammaRIIA genotype. In conclusion, FcgammaRIIA polymorphism did not correlate with the manifestations of APS, and FcgammaRIIA genotype is not a genetic marker of APS.