A systematic experimental investigation to understand the effect of heat loss and the thermoelectric aspect ratio (cross sectional area and length) on a flat plate solar thermoelectric system performance was carried o...A systematic experimental investigation to understand the effect of heat loss and the thermoelectric aspect ratio (cross sectional area and length) on a flat plate solar thermoelectric system performance was carried out. The investigation involved a series of experiments on systems with 4 different sizes of thermoelectric generators, and it was tested in 5 different vacuum levels during the steady-state. The detailed experimental investigation provided a substantial amount of data, which revealed that the system performance of both heat and electricity power were improved when the heat lost was minimised. The system’s performance strongly depended on the aspect ratio of the thermoelectric generators. This finding might have a significant impact on the cost of the system by saving the user’s and the manufacturer’s time in examining different TEGs with different aspect ratios in order to get the optimum size optimisation of the hybrid system, as well as reduce the manufacturing cost.展开更多
We study the optical properties of a two-level atomic ensemble controlled by a high-finesse cavity. Even though the cavity is initially in the vacuum state in the absence of external driving, the probe response of the...We study the optical properties of a two-level atomic ensemble controlled by a high-finesse cavity. Even though the cavity is initially in the vacuum state in the absence of external driving, the probe response of the atomic ensemble can be dramatically modified. When the collectively enhanced atom–cavity coupling is strong enough and the cavity decay rate is much smaller than the atomic damping rate, an electromagnetically induced transparency-like coherent phenomenon emerges with a dip absorption for the response of the two-level atoms in the cavity without driving, and thus is called vacuum induced transparency. We also show the slow light with very low group velocity in such an atomic ensemble.展开更多
In this paper,energy loss of alpha particles in different vacuum levels is studied experimentally and via theoretical analysis.A better understanding of energy loss of a particle in vacuum will help detect more exact ...In this paper,energy loss of alpha particles in different vacuum levels is studied experimentally and via theoretical analysis.A better understanding of energy loss of a particle in vacuum will help detect more exact numbers of alpha particles.Two ^(239)Pu sources are used to measure the energy loss of a particle crossing different vacuum levels (different air pressures).The experimental data are obtained from an instrument-PAM-100 developed by authors. The experimental results have shown that increasing vacuum levels will lead to more alpha residual energy but less energy loss.When the vacuum level reaches 0.04 MPa,alpha particles(^(239)Pu,5.115 MeV)will lose the energy of about 0.175 MeV with traversing 5 mm distance.Theoretical calculations have shown a good agreement with experimental results.This implies that the instrument has a high accuracy and could be applied in field work.展开更多
圆片级真空封装是提高微电子机械系统(Micro-Electro-Mechanical Systems,MEMS)电场传感器品质因数及批量化制造效率的重要途径.本文提出了一种基于绝缘体上硅(Silicon On Insulator,SOI)-玻璃体上硅(Silicon On Glass,SOG)键合的圆片...圆片级真空封装是提高微电子机械系统(Micro-Electro-Mechanical Systems,MEMS)电场传感器品质因数及批量化制造效率的重要途径.本文提出了一种基于绝缘体上硅(Silicon On Insulator,SOI)-玻璃体上硅(Silicon On Glass,SOG)键合的圆片级真空封装MEMS电场传感器,设计并实现了从传感器敏感结构制备到真空封装的整套圆片级加工工艺.本文建立了传感器的结构电容模型,进行了有限元仿真,分析了传感器的特性,突破了传感器微结构制备与释放、SOI与SOG键合等工艺技术难点.该传感器具有工作电压低、品质因数高的突出优点.实验结果表明,工作电压仅为5 V直流与0.05 V交流电压.在60天测试过程中,传感器品质因数始终保持在5000以上.在0~50 kV/m范围内,传感器灵敏度为0.15 mV/(kV/m),线性度为2.21%,不确定度为4.74%.展开更多
文摘A systematic experimental investigation to understand the effect of heat loss and the thermoelectric aspect ratio (cross sectional area and length) on a flat plate solar thermoelectric system performance was carried out. The investigation involved a series of experiments on systems with 4 different sizes of thermoelectric generators, and it was tested in 5 different vacuum levels during the steady-state. The detailed experimental investigation provided a substantial amount of data, which revealed that the system performance of both heat and electricity power were improved when the heat lost was minimised. The system’s performance strongly depended on the aspect ratio of the thermoelectric generators. This finding might have a significant impact on the cost of the system by saving the user’s and the manufacturer’s time in examining different TEGs with different aspect ratios in order to get the optimum size optimisation of the hybrid system, as well as reduce the manufacturing cost.
基金Project supported by the National Natural Science Foundation of China(Grant No.11304010)
文摘We study the optical properties of a two-level atomic ensemble controlled by a high-finesse cavity. Even though the cavity is initially in the vacuum state in the absence of external driving, the probe response of the atomic ensemble can be dramatically modified. When the collectively enhanced atom–cavity coupling is strong enough and the cavity decay rate is much smaller than the atomic damping rate, an electromagnetically induced transparency-like coherent phenomenon emerges with a dip absorption for the response of the two-level atoms in the cavity without driving, and thus is called vacuum induced transparency. We also show the slow light with very low group velocity in such an atomic ensemble.
基金Supported by the National Natural Science Foundation of China(Grant No.40974065)the National Science Foundation for Distinguished Young Scholars of China(Grant No.41025015)
文摘In this paper,energy loss of alpha particles in different vacuum levels is studied experimentally and via theoretical analysis.A better understanding of energy loss of a particle in vacuum will help detect more exact numbers of alpha particles.Two ^(239)Pu sources are used to measure the energy loss of a particle crossing different vacuum levels (different air pressures).The experimental data are obtained from an instrument-PAM-100 developed by authors. The experimental results have shown that increasing vacuum levels will lead to more alpha residual energy but less energy loss.When the vacuum level reaches 0.04 MPa,alpha particles(^(239)Pu,5.115 MeV)will lose the energy of about 0.175 MeV with traversing 5 mm distance.Theoretical calculations have shown a good agreement with experimental results.This implies that the instrument has a high accuracy and could be applied in field work.
文摘圆片级真空封装是提高微电子机械系统(Micro-Electro-Mechanical Systems,MEMS)电场传感器品质因数及批量化制造效率的重要途径.本文提出了一种基于绝缘体上硅(Silicon On Insulator,SOI)-玻璃体上硅(Silicon On Glass,SOG)键合的圆片级真空封装MEMS电场传感器,设计并实现了从传感器敏感结构制备到真空封装的整套圆片级加工工艺.本文建立了传感器的结构电容模型,进行了有限元仿真,分析了传感器的特性,突破了传感器微结构制备与释放、SOI与SOG键合等工艺技术难点.该传感器具有工作电压低、品质因数高的突出优点.实验结果表明,工作电压仅为5 V直流与0.05 V交流电压.在60天测试过程中,传感器品质因数始终保持在5000以上.在0~50 kV/m范围内,传感器灵敏度为0.15 mV/(kV/m),线性度为2.21%,不确定度为4.74%.
