NEC Corporation is a Japanese multinational provider of information technology services and products, with its headquarters in Minato, Tokyo, Japan. NEC provides information technology and network solutions to business enterprises, communications services providers and to government agencies. The company was known as the Nippon Electric Company, Limited, before rebranding in 1983 as just NEC. Its NEC Semiconductors business unit was one of the worldwide top 20 semiconductor sales leaders before merging it with Renesas Electronics. NEC is a member of the Sumitomo Group. Wikipedia.
Okamoto Y.,NEC Corp
Journal of the Electrochemical Society | Year: 2012
First-principles calculations were done to examine the effect of oxygen vacancies in Li 2MnO 3 on the lithium extraction from the crystal. As the ratio of O-vacancy increases, the redox potential associated with the lithium extraction decreases and the Mn contribution in the charge compensation for the lithium extraction increases. These findings indicate that the introduction of O-vacancy activates the Mn sites as the redox center in the lithium extraction process. However, the lithium extraction from Li 2MnO 3 tends to cause successive O 2 evolution from the crystal. This results in a high O-vacancy density in the crystal, which in turn triggers a drastic volume reduction during the lithium extraction process. © 2011 The Electrochemical Society. Source
Okamotoz Y.,NEC Corp
Journal of the Electrochemical Society | Year: 2013
The Smart Energy Research Laboratories, NEC Corporation, Tsukuba, Ibaraki 305-8501, Japan Ab initio molecular orbital calculations were done to examine the thermal decomposition mechanism of LiPF6-based electrolyte such as LiPF6 dissolved into carbonate ester.We focused our study on LiPF6 decomposition (LiPF6 + H2O→LiF + POF3 + 2HF) and ethylene carbonate decomposition (EC + POF 3rarr;CO2 + CH2FCH2OPF 2O). Intrinsic reaction coordinate calculations showed that the latter reaction has a significantly high reaction barrier more than 3 eV. However, we found that it may be reduced by 0.97 eV by considering PF 6 - ion which acts as a kind of catalyst in the reaction. Although POF3 triggers EC ring opening reaction unless both Li + and PF6 - ions are considered in the model, it remains a spectator in the C-O bond breaking reaction of diethyl carbonate (DEC) by PF6-. © 2013 The Electrochemical Society. Source
NEC Corp | Date: 2016-01-12
A communication system is presented in which a base station is provided for communicating with a plurality of mobile communication devices in a cellular communication system. The base station operates one of more communication cells and communicates subframes, with each of the plurality of communication devices within the cell(s), each comprising the communication resources of a control region for communicating a control channel and the communication resources of a data region for communicating a respective data channel. The base station communicates a control channel having a first DMRS sequence in a control region of some subframes and a control channel having a second DMRS sequence in a control region of other subframes. The second control channel may be transmitted in a radio beam focussed spatially in a direction of a communication device. The first control channel may be transmitted omnidirectionally throughout the cell(s).
NEC Corp | Date: 2016-01-08
A core network includes a plurality of nodes that serve as nodes managing mobility of a terminal and that are different with regards to service functions that nodes provide to the terminal. Based on subscriber information and terminal information, a node to be connected to the terminal is selected on the core network side, depending on a service characteristic utilized by the terminal or on a type of the terminal and the terminal is connected to the selected node.
NEC Corp | Date: 2015-10-09
A radio communication device that communicates with other radio communication devices that become communication partners includes first detection means that detects moving states of said other radio communication devices; second detection means that detects a moving state of its own device; third detection means that detects a congestion level of communication between said other radio communication devices or a congestion level of communication between said other radio communication devices and said own device; transmission means that transmits a radio signal from said own device to said other communication devices; and control means that controls said transmission means to transmit the radio signal based on the moving states of said other radio communication devices, the moving state of said own device, and said congestion level.