NEC

About: NEC is a company organization based out in Tokyo, Japan. It is known for research contribution in the topics: Signal & Layer (electronics). The organization has 33269 authors who have published 57670 publications receiving 835952 citations. The organization is also known as: NEC Corporation & NEC Electronics Corporation.

Selective deposition of a gadolinium(III) cluster in a hole opening of single-wall carbon nanohorn

Abstract: Selective synthesis of particles of angstrom to nanometer size consisting of one to many metal atoms is instrumental in various applications, but it has been hampered by the tendency of the metal atom to form large clusters. We found, as studied by the state-of-the-art electron microscopic technique, a strategy to produce metal-containing nanoparticles isolated from each other by depositing metal atoms in a hydrophilic hole on or in the interior of a carbon nanotube as demonstrated by the reaction of Gd(OAc)3 with oxidized single-wall nanohorns. Besides the potential utilities of the deposited metal clusters, the metal deposition protocol provides a method to control permeation of molecules through such openings.

Piezoelectric transformer driving circuit

Abstract: A piezoelectric transformer driving circuit includes a boosting circuit receiving an input DC voltage to generate an AC voltage for driving a piezoelectric transformer, a frequency control circuit for controlling the frequency of the AC voltage applied to the piezoelectric transformer to control a step-up ratio of the piezoelectric transformer, and a drive voltage control circuit for controlling the voltage of the AC voltage applied to the piezoelectric transformer at a predetermined level, regardless of variation of the input DC voltage.

Variation in Tc, structure and oxygen content in Tl2Ba2CuO6 and their correlations

Abstract: The preparation condition of Tl 2 Ba 2 CuO 6 (2201 compound) and its properties including superconductivities and structural variations were studied. Preparation at relatively low heat-treatment temperatures produced the 2201 compound with an orthorhombic symmetry, while heat-treatment above 840°C produced a tetragonal symmetry. It was revealed that the appearance of superconductivity was independent of the structural symmetry, and was strongly affected by oxygen content. Decrease of oxygen content by quenching or Ar-annealing increased the superconducting transition temperatures up to about 70 K. A positive correlation between T c and the c -axis length was also found for all samples including both orthorhombic and tetragonal structures.

A 25.6 W 13.56 MHz wireless power transfer system with a 94% efficiency GaN Class-E power amplifier

Abstract: In this work, we propose the design and implementation of a 13.56 MHz GaN Class-E power amplifier, which takes into account transistor parasitic effects. The design uses the parasitic capacitance of the transistor to replace the charging capacitance, simplifying the circuit structure and obtaining a 93.6% efficiency at output power of 26.8 W. In addition, a wireless power transfer system using the proposed Class-E amplifier is demonstrated, achieving a 73.4% system efficiency when the power delivered to the load is 25.6 W.

Path establishment method for establishing paths of different fault recovery types in a communications network

Abstract: In a communications network where multiple shared risk link groups are formed by links having a common risk, unreserved bandwidths are defined corresponding to all SRLG's and a maximum bandwidth of each link is set as an initial value of each of the defined unreserved bandwidths when a working path or a protection path of “1+1” or “1:1” recovery type is requested. When a protection path of “shared” recovery type is requested, unreserved bandwidths are defined corresponding to the SRLG's to which the links of its corresponding working path belong and a maximum bandwidth of each link is set as an initial value to each of the defined unreserved bandwidths. The bandwidth of the working or protection path is subtracted from each of the unreserved bandwidths. The request is rejected if a minimum of the subtracted values is smaller than a threshold.