当前使用的大型储电系统很昂贵，要求高温和大的基础，有时还有潜在危险。美国国家能源技术研究所（National Energy Technology Laboratory）从事此替代技术研究，旨在于降低价格、使大型储能系统安全和更加实用，研究内容包括适用的...当前使用的大型储电系统很昂贵，要求高温和大的基础，有时还有潜在危险。美国国家能源技术研究所（National Energy Technology Laboratory）从事此替代技术研究，旨在于降低价格、使大型储能系统安全和更加实用，研究内容包括适用的阳极、阴极以及镁、钠和锂电池以及新型过渡金属氧化物和氮化物基电容电极材料。同时，研究人员还研究廉价的高能密度储能器的多种潜在途径。该所还在研究制造电池的新阳极材料，使镁、钠电池工作更为理想，改善锂电池性能；在双联电容器中使用过渡族元素氧化物和超结构氧化物，以获得可长期储能（电）的备用脉冲储电设施，如电池和燃料电池。此储能（电）系统可保持稳定的基础负荷，以满足多种要求和使电分布更可靠，更有效。WWW．netl．doe．展开更多
The activated nitrogen-enriched novel carbons (NENCs) were prepared by direct carbonization using polyaniline coating activated mesocarbon microbead composites as the precursor. Herein the influences of the carbonizat...The activated nitrogen-enriched novel carbons (NENCs) were prepared by direct carbonization using polyaniline coating activated mesocarbon microbead composites as the precursor. Herein the influences of the carbonization temperature on the structure and morphology of the NENCs samples were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and N2 adsorption/desorption isotherm at 77 K. The electrochemical properties of the supercapacitors were characterized by cyclic voltammetry, galvanostatic charge/discharge, electrochemical impedance spectroscopy (EIS), cycle life, leakage current and self-discharge measurements in 6 mol/L KOH solution. The results demonstrate that the NENC samples carbonized at 600 °C show the highest specific capacitance of 385 F/g at the current density of 1 A/g and the lowest ESR value (only 0.93?). Furthermore, the capacity retention ratio of the NENCs-600 supercapacitor is 92.8 % over 2500 cycles.展开更多
Based on the proper assumptions and approximations, the coupling mechanism of the electromagnetic acoustic transducer (EMAT) for ultrasonic generation within ferromagnetic material was studied by analyzing the eddy cu...Based on the proper assumptions and approximations, the coupling mechanism of the electromagnetic acoustic transducer (EMAT) for ultrasonic generation within ferromagnetic material was studied by analyzing the eddy current distribution, Lorentz force, magnetostriction force and magnetization force. Some useful numerical calculations are presented to explain the EMAT behavior with general geometric arrangements. It is indicated that for the ferromagnetic material the magnetostriction effect dominates the EMAT phenomenon for ultrasonic wave generation in low magnetic field intensity, while the material does not reach its magnetizing saturation. But, with the increase of the bias magnetic field and saturation, the magnetostrictive terms will make no contributions to the ultrasonic generation and the Lorentz force becomes the only exciting mechanism. It is important to determine both the Lorentz and magnetostriction forces and select the appropriate working manner for achieving an optimized design.展开更多
The use of piezoelectric material sensors in smart composite structures is investigated. An experimental structure bonded with lead zirconate titanate piezoelectric ceramic(PZT) sensors is developed. These bonded sens...The use of piezoelectric material sensors in smart composite structures is investigated. An experimental structure bonded with lead zirconate titanate piezoelectric ceramic(PZT) sensors is developed. These bonded sensors are employed to monitor load variations and transient impacts in the structure. Incorporated with pattern recognition approach, PZT sensors have succeeded in detecting the onset and location of damages.展开更多
文摘当前使用的大型储电系统很昂贵，要求高温和大的基础，有时还有潜在危险。美国国家能源技术研究所（National Energy Technology Laboratory）从事此替代技术研究，旨在于降低价格、使大型储能系统安全和更加实用，研究内容包括适用的阳极、阴极以及镁、钠和锂电池以及新型过渡金属氧化物和氮化物基电容电极材料。同时，研究人员还研究廉价的高能密度储能器的多种潜在途径。该所还在研究制造电池的新阳极材料，使镁、钠电池工作更为理想，改善锂电池性能；在双联电容器中使用过渡族元素氧化物和超结构氧化物，以获得可长期储能（电）的备用脉冲储电设施，如电池和燃料电池。此储能（电）系统可保持稳定的基础负荷，以满足多种要求和使电分布更可靠，更有效。WWW．netl．doe．
基金Projects(51072173,51272221)supported by the National Natural Science Foundation of ChinaProject(20094301110005)supported by Specialized Research Fund for the Doctoral Program of Higher Education,ChinaProject(2013FJ4062)supported by Science and Technology Plan Foundation of Hunan Province,China
文摘The activated nitrogen-enriched novel carbons (NENCs) were prepared by direct carbonization using polyaniline coating activated mesocarbon microbead composites as the precursor. Herein the influences of the carbonization temperature on the structure and morphology of the NENCs samples were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and N2 adsorption/desorption isotherm at 77 K. The electrochemical properties of the supercapacitors were characterized by cyclic voltammetry, galvanostatic charge/discharge, electrochemical impedance spectroscopy (EIS), cycle life, leakage current and self-discharge measurements in 6 mol/L KOH solution. The results demonstrate that the NENC samples carbonized at 600 °C show the highest specific capacitance of 385 F/g at the current density of 1 A/g and the lowest ESR value (only 0.93?). Furthermore, the capacity retention ratio of the NENCs-600 supercapacitor is 92.8 % over 2500 cycles.
文摘Based on the proper assumptions and approximations, the coupling mechanism of the electromagnetic acoustic transducer (EMAT) for ultrasonic generation within ferromagnetic material was studied by analyzing the eddy current distribution, Lorentz force, magnetostriction force and magnetization force. Some useful numerical calculations are presented to explain the EMAT behavior with general geometric arrangements. It is indicated that for the ferromagnetic material the magnetostriction effect dominates the EMAT phenomenon for ultrasonic wave generation in low magnetic field intensity, while the material does not reach its magnetizing saturation. But, with the increase of the bias magnetic field and saturation, the magnetostrictive terms will make no contributions to the ultrasonic generation and the Lorentz force becomes the only exciting mechanism. It is important to determine both the Lorentz and magnetostriction forces and select the appropriate working manner for achieving an optimized design.
文摘The use of piezoelectric material sensors in smart composite structures is investigated. An experimental structure bonded with lead zirconate titanate piezoelectric ceramic(PZT) sensors is developed. These bonded sensors are employed to monitor load variations and transient impacts in the structure. Incorporated with pattern recognition approach, PZT sensors have succeeded in detecting the onset and location of damages.
