the power network fault detection system can only analyze all kinds of fault signal in stationary sequence： the internal grid and external disturbance presents degeneration, tiny, signal intensity changes randomly fl...the power network fault detection system can only analyze all kinds of fault signal in stationary sequence： the internal grid and external disturbance presents degeneration, tiny, signal intensity changes randomly fluctuate, that will cause the system to detect the fault isolation ability of confusion and small fault signal is not strong; The article propose a method of power network fault detection for based on GSM, Through the underlying sensing equipment acquisition abnormal information of current, voltage power in the network and GSM networking scheme can filter the interference factors in extraction of fault information from and attribute value. The embedded gateway take STM32 chip as the core to monitoring data processing, to achieve a unified data management and user remote access, realizing method of system software are given, to construct the monitor management information platform. The actual test system show that, identification diagnosis ability of fault signal separation ability and small signal increases 17%, also meet the requirements.展开更多
We apply polyelectrolyte multilayer films by consecutive alternate adsorption of positively charged polyallylamine hydrochloride and negatively charged sodium polystyrene sulfonate to the surface of graphene field eff...We apply polyelectrolyte multilayer films by consecutive alternate adsorption of positively charged polyallylamine hydrochloride and negatively charged sodium polystyrene sulfonate to the surface of graphene field effect transistors. Oscillations in the Dirac voltage shift with alternating positive and negative layers clearly demonstrate the electrostatic gating effect in this simple model system. A simple electrostatic model accounts well for the sign and magnitude of the Dirac voltage shift. Using this system, we are able to create p-type or n-type graphene at will. This model serves as the basis for understanding the mechanism of charged polymer sensing using graphene devices, a potentially technologically important application of graphene in areas such as DNA sequencing, biomarker assays for cancer detection, and other protein sensing applications.展开更多
文摘the power network fault detection system can only analyze all kinds of fault signal in stationary sequence： the internal grid and external disturbance presents degeneration, tiny, signal intensity changes randomly fluctuate, that will cause the system to detect the fault isolation ability of confusion and small fault signal is not strong; The article propose a method of power network fault detection for based on GSM, Through the underlying sensing equipment acquisition abnormal information of current, voltage power in the network and GSM networking scheme can filter the interference factors in extraction of fault information from and attribute value. The embedded gateway take STM32 chip as the core to monitoring data processing, to achieve a unified data management and user remote access, realizing method of system software are given, to construct the monitor management information platform. The actual test system show that, identification diagnosis ability of fault signal separation ability and small signal increases 17%, also meet the requirements.
文摘We apply polyelectrolyte multilayer films by consecutive alternate adsorption of positively charged polyallylamine hydrochloride and negatively charged sodium polystyrene sulfonate to the surface of graphene field effect transistors. Oscillations in the Dirac voltage shift with alternating positive and negative layers clearly demonstrate the electrostatic gating effect in this simple model system. A simple electrostatic model accounts well for the sign and magnitude of the Dirac voltage shift. Using this system, we are able to create p-type or n-type graphene at will. This model serves as the basis for understanding the mechanism of charged polymer sensing using graphene devices, a potentially technologically important application of graphene in areas such as DNA sequencing, biomarker assays for cancer detection, and other protein sensing applications.
