Switching Surge Duty of Metal Oxide Surge Arresters in Multi-Phases' System and Its Equivalent Conditions in a Test

Switching surge duty test imposing the highest power dissipation on high voltage metal oxide arresters has usually been done with a single phase circuit due to the limit of test facilities, in spite of complex multi-phases in a service system. The purpose of this paper is to propose new equivalent line constants and reasonable conditions of charging voltage in a test circuit, which were derived from the application study of surge arresters on double circuits and transposed 500kV lines. So-called positive, negative, zero, self and mutual mode impedances are not equivalent. Other impedances must be used and some correctiorts for charging voltage are required in a transmission line discharge test.     

Monoclonality of both pale cells and cuboidal cells of sclerosing hemangioma of the lung

Sclerosing hemangioma of the lung remains poorly understood, and it is still unclear whether this lesion is neoplastic or not. It consists of two major cell types, pale cells and cuboidal cells. We analyzed the clonality of each cell types from six female cases of surgically resected sclerosing hemangioma. The pale cells and cuboidal cells were separated by microdissection from methanol-fixed sections, and DNA was extracted for clonal analysis based on an X-chromosome-linked polymorphic marker, the human androgen receptor (HUMARA) gene or the phosphoglycerate kinase (PGK) gene. The HUMARA and PGK genes were found to be amplified with or without digestion by the methylation-sensitive restrictive endonuclease HpaII. Five of six cases were informative. Pale cells and cuboidal cells showed the same monoclonality in all of the informative cases, whereas the control cells showed a polyclonal pattern. Our results demonstrated that sclerosing hemangioma is caused by monoclonal expansion of cells, confirming that it is a neoplasia. Moreover, the present data indicate that both pale cells and cuboidal cells are derived from the same cell.     

Effects of buoyancy and of acceleration owing to thermal expansion on forced turbulent convection in vertical circular tubes—criteria of the effects,velocity and temperature profiles,and reverse transition from turbulent to laminar flow

In this paper, turbulent heat and momentum transfer for a fluid forced through a vertical tube is considered. First, the authors study a shearing-stress distribution in a tube, by taking the buoyancy force and also the inertia force due to acceleration into consideration. It is proved that the effects of both forces operate quite similarly and result in a very rapid decrease of the shearing stress near the wall. By considering how the velocity profile depends upon the shearing-stress gradient at the wall, the authors deduce the criteria for the prominent effects of buoyancy and acceleration. Second, by assuming that the turbulent boundary layer is constructed by the superposition of the locally developed layers, the authors propose an approximate theory to calculate velocity and temperature profiles under the large effects of buoyancy and acceleration. Thirdly, based on the above theory, a criterion of the reverse transition from turbulent to laminar flow is proposed.     

Direct Synthesis of N‐Acyl‐N,O‐hemiacetals via Nucleophilic Addition of Unactivated Amides and Their O‐Acetylation: Access to α,α‐Difunctionalized N‐Acylimines

A mild, metal‐free synthesis of polyfunctionalized N‐acyl‐N,O‐hemiacetals was developed via the nucleophilic addition of unactivated amides to ketones. The protocol demonstrated a wide substrate scope, with good isolated yields. Additionally, their O‐acetylated products serve as a precursor of α,α‐difunctionalized N‐acylimines. An addition reaction of broad scope of nucleophiles to generate N‐acylimines is also reported.

     

The experimental humanoid robot H7: a research platform for autonomous behaviour

This paper gives an overview of the humanoid robot 'H7', which was developed over several years as an experimental platform for walking, autonomous behaviour and human interaction research at the University of Tokyo. H7 was designed to be a human-sized robot capable of operating autonomously in indoor environments designed for humans. The hardware is relatively simple to operate and conduct research on, particularly with respect to the hierarchical design of its control architecture. We describe the overall design goals and methodology, along with a summary of its online walking capabilities, autonomous vision-based behaviours and automatic motion planning. We show experimental results obtained by implementations running within a simulation environment as well as on the actual robot hardware.     

Cu(In,Ga)Se2 solar cell grown on flexible polymer substrate with efficiency exceeding 17%

Development of a Cu(In,Ga)Se₂ thin film solar cell on a polyimide film with a conversion efficiency of 17.1%, measured under standard test conditions at the European Solar Test Installation (ESTI) of the Joint Research Centre (JRC) of the European Commission, Ispra, is reported. The drastic improvement from the previous record of 14.1% efficiency is attributed to a more optimized compositional grading, better structural and electronic properties of the absorber layer as well as reduced reflection losses. Basic film and device properties, which led to the improvement in the efficiency record of flexible solar cells are presented for the new process and compared to the old process. Copyright © 2011 John Wiley & Sons, Ltd.     

Formation and atomic structures of boron nitride nanohorns

Boron nitride (BN) nanohorns were synthesized by an arc-melting method, and atomic structure models for BN nanohorns with tetragonal BN rings were proposed from high-resolution electron microscopy. Stability and electronic structures of the BN nanohorns were investigated by molecular orbital/mechanics calculations. The calculation showed that multiwalled BN nanohorns would be stabilized by stacking of BN nanohorns. The energy gap of BN nanohorn was calculated to be 0.8 eV, which is lower compared to those of BN clusters and nanotubes.