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.

Crystallization behavior and mechanical properties of bio‐based green composites based on poly(L‐lactide) and kenaf fiber

Abstract: Bio-based polymer composite was successfully fabricated from plant-derived kenaf fiber (KF) and renewable resource-based biodegradable polyester, poly(L-lactide) (PLLA), by melt-mixing technique. The effect of the KF weight contents (0, 10, 20, and 30 wt %) on crystallization behavior, composite morphology, mechanical, and dynamic mechanical properties of PLLA/KF composites were investigated. It was found that the incorporation of KF significantly improves the crystallization rate and tensile and storage modulus. The crystallization of PLLA can be completed during the cooling process from the melt at 5°C/min with the addition of 10 wt % KF. It was also observed that the nucleation density increases dramatically and the spherulite size drops greatly in the isothermal crystallization with the presence of KF. In addition, with the incorporation of 30 wt % KF, the half times of isothermal crystallization at 120°C and 140°C were reduced to 46.5% and 28.1% of the pure PLLA, respectively. Moreover, the tensile and storage modulus of the composite are improved by 30% and 28%, respectively, by the reinforcement with 30% KF. Scanning electron microscopy observation also showed that the crystallization rate and mechanical properties could be further improved by optimizing the interfacial interaction and compatibility between the KF and PLLA matrix. Overall, it was concluded that the KF could be the potential and promising filler for PLLA to produce biodegradable composite materials, owing to its good ability to improve the mechanical properties as well as to accelerate the crystallization of PLLA. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007

Method and system for image querying using region based and boundary based image matching

Abstract: A method and apparatus for querying a database of images, in which the results of the query are based upon a combination of region based image matching and boundary based image matching. Additionally similarity calculations are made between individual results of the query so that the results may be clustered based upon similarity.

Method of preventing interference of adjacent frequencies in a cellular system by selection between adjacent carrier frequency and non-adjacent carrier frequency

Abstract: A method of preventing interference of adjacent frequencies which selects and uses a carrier frequency which is not adjacent to another carrier frequency is disclosed. A cellular system A is composed of a plurality of base stations and a mobile station, and a cellular system B is composed of a plurality of other base stations and another mobile station. For cellular system A, a carrier frequency adjacent to a carrier frequency used in cellular system B and a carrier frequency not adjacent thereto are determined. If a received power of a perch channel sent by a base station of cellular system B is larger than a threshold value, the mobile station uses the carrier frequency which is not adjacent to carrier frequency used in cellular system B.

SSDT-site selection diversity transmission power control for CDMA forward link

Abstract: This paper proposes site selection diversity transmission power control (SSDT), an advanced form of transmission power control (TPC) for CDMA forward link, SSDT realizes site selection transmission diversity instead of full site transmission diversity used in conventional TPC during soft hand over (SHO) mode. The major intention of the site selection is to mitigate interference caused by multiple site transmission done at conventional TPC. Simulation results indicated that the higher the capacity gain of SSDT is in comparison to conventional TPC, the lower the mobile station (MS) speed is. Capacity gain of about 55% for a pedestrian MS is achieved by SSDT in case of MS reception diversity and 6 finger RAKE reception. This paper also presents the benefits of SSDT in terms of its high path capturing efficiency and the mitigation of power imbalance among active BSs due to TPC command reception error.

Fast Tunable Coupler for Superconducting Qubits

Abstract: A major challenge in the field of quantum computing is the construction of scalable qubit coupling architectures. Here, we demonstrate a novel tunable coupling circuit that allows superconducting qubits to be coupled over long distances. We show that the interqubit coupling strength can be arbitrarily tuned over nanosecond time scales within a sequence that mimics actual use in an algorithm. The coupler has a measured on/off ratio of 1000. The design is self-contained and physically separate from the qubits, allowing the coupler to be used as a module to connect a variety of elements such as qubits, resonators, amplifiers, and readout circuitry over distances much larger than nearest-neighbor. Such design flexibility is likely to be useful for a scalable quantum computer.