Annular gate nMOSFETs are frequently used in spaceborne integrated circuits due to their intrinsic good capability of resisting total ionizing dose (TID) effect. However, their capability of resisting the hot carrie...Annular gate nMOSFETs are frequently used in spaceborne integrated circuits due to their intrinsic good capability of resisting total ionizing dose (TID) effect. However, their capability of resisting the hot carrier effect (HCE) has also been proven to be very weak. In this paper, the reason why the annular gate nMOSFETs have good TID but bad HCE resistance is discussed in detail, and an improved design to locate the source contacts only along one side of the annular gate is used to weaken the HCE degradation. The good TID and HCE hardened capability of the design are verified by the experiments for I/O and core nMOSFETs in a 0.18 μm bulk CMOS technology. In addition, the shortcoming of this design is also discussed and the TID and the HCE characteristics of the replacers (the annular source nMOSFETs) are also studied to provide a possible alternative for the designers.展开更多
Chemical effects on the Kβ/Kα intensity ratios and △E energy differences for Co, Ni, Cu, and Zn complexes were investigated. The samples were excited by 59.5 keV γ-rays from a ^241Am annular radioactive source. K ...Chemical effects on the Kβ/Kα intensity ratios and △E energy differences for Co, Ni, Cu, and Zn complexes were investigated. The samples were excited by 59.5 keV γ-rays from a ^241Am annular radioactive source. K X-rays emitted by samples were counted by an Ultra-LEGe detector with a resolution of 150 eV at 5.9 keV. We observed the effects of different ligands on the Kβ/Kα intensity ratios and △E energy differences for Co, Ni, Cu, and Zn complexes. We tried to investigate chemical effects on central atoms using the behaviors of different ligands in these complexes. The experimental values of Kβ/Kα were compared with the theoretical and other experimental values of pure Co, Ni, Cu, and Zn.展开更多
Based on the extended closed-orbit theory together with spectral analysis, this paper studies the correspondence between quantum mechanics and the classical counterpart in a two-dimensional annular billiard. The resul...Based on the extended closed-orbit theory together with spectral analysis, this paper studies the correspondence between quantum mechanics and the classical counterpart in a two-dimensional annular billiard. The results demonstrate that the Fourier-transformed quantum spectra are in very good accordance with the lengths of the classical ballistic trajectories, whereas spectral strength is intimately associated with the shapes of possible open orbits connecting arbitrary two points in the annular cavity. This approach facilitates an intuitive understanding of basic quantum features such as quantum interference, locations of the wavefunctions, and allows quantitative calculations in the range of high energies, where full quantum calculations may become impractical in general. This treatment provides a thread to explore the properties of microjunction transport and even quantum chaos under the much more general system.展开更多
As the width-thickness ratio of the discrete nozzle atomizer’s discrete hole greatly influences the loss of atomizing gas flow rate,the discrete nozzle atomizer was transformed into an annular slit atomizer with the ...As the width-thickness ratio of the discrete nozzle atomizer’s discrete hole greatly influences the loss of atomizing gas flow rate,the discrete nozzle atomizer was transformed into an annular slit atomizer with the same total nozzle outlet area.A numerical simulation study on the effect of various parameters on the atomization in the annular slit atomizer was carried out by coupling both the large eddy simulation(LES)and volume of fluid(VOF)model,which is based on the applicability of LES in capturing the breakup behavior of transient liquid droplets and the advantage of VOF method in directly capturing the phase interface.The simulation results showed that the increase in the atomization pressure makes the gas gain higher momentum,while the increase in the nozzle intersection angle decreases the distance between the nozzle exit and the computational domain axis.The increase in these two variables results in enhancing the gas-liquid interaction in the primary atomization zone and the formation of more aluminum droplets simultaneously.It is considered that the atomization effect becomes better when atomization pressure is 2.5 MPa,and the nozzle intersection angle is 60°.Industrial tests showed that the aluminum powder prepared by the optimized annular slit atomizer has a finer mean particle size and a higher yield of fine powder.The numerical simulation results agree well with the industrial test data of the powder particle size.展开更多
基金supported by the Key Program of the National Natural Science Foundation of China(Grant No.60836004)the National Natural Science Foundation of China(Grant Nos.61006070 and 61076025)
文摘Annular gate nMOSFETs are frequently used in spaceborne integrated circuits due to their intrinsic good capability of resisting total ionizing dose (TID) effect. However, their capability of resisting the hot carrier effect (HCE) has also been proven to be very weak. In this paper, the reason why the annular gate nMOSFETs have good TID but bad HCE resistance is discussed in detail, and an improved design to locate the source contacts only along one side of the annular gate is used to weaken the HCE degradation. The good TID and HCE hardened capability of the design are verified by the experiments for I/O and core nMOSFETs in a 0.18 μm bulk CMOS technology. In addition, the shortcoming of this design is also discussed and the TID and the HCE characteristics of the replacers (the annular source nMOSFETs) are also studied to provide a possible alternative for the designers.
文摘Chemical effects on the Kβ/Kα intensity ratios and △E energy differences for Co, Ni, Cu, and Zn complexes were investigated. The samples were excited by 59.5 keV γ-rays from a ^241Am annular radioactive source. K X-rays emitted by samples were counted by an Ultra-LEGe detector with a resolution of 150 eV at 5.9 keV. We observed the effects of different ligands on the Kβ/Kα intensity ratios and △E energy differences for Co, Ni, Cu, and Zn complexes. We tried to investigate chemical effects on central atoms using the behaviors of different ligands in these complexes. The experimental values of Kβ/Kα were compared with the theoretical and other experimental values of pure Co, Ni, Cu, and Zn.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 10374061 and 10774093)
文摘Based on the extended closed-orbit theory together with spectral analysis, this paper studies the correspondence between quantum mechanics and the classical counterpart in a two-dimensional annular billiard. The results demonstrate that the Fourier-transformed quantum spectra are in very good accordance with the lengths of the classical ballistic trajectories, whereas spectral strength is intimately associated with the shapes of possible open orbits connecting arbitrary two points in the annular cavity. This approach facilitates an intuitive understanding of basic quantum features such as quantum interference, locations of the wavefunctions, and allows quantitative calculations in the range of high energies, where full quantum calculations may become impractical in general. This treatment provides a thread to explore the properties of microjunction transport and even quantum chaos under the much more general system.
基金the financial support provided by the National Natural Science Foundation of China(U21A20317)supported by High-Performance Computing Center of Wuhan University of Science and Technology.
文摘As the width-thickness ratio of the discrete nozzle atomizer’s discrete hole greatly influences the loss of atomizing gas flow rate,the discrete nozzle atomizer was transformed into an annular slit atomizer with the same total nozzle outlet area.A numerical simulation study on the effect of various parameters on the atomization in the annular slit atomizer was carried out by coupling both the large eddy simulation(LES)and volume of fluid(VOF)model,which is based on the applicability of LES in capturing the breakup behavior of transient liquid droplets and the advantage of VOF method in directly capturing the phase interface.The simulation results showed that the increase in the atomization pressure makes the gas gain higher momentum,while the increase in the nozzle intersection angle decreases the distance between the nozzle exit and the computational domain axis.The increase in these two variables results in enhancing the gas-liquid interaction in the primary atomization zone and the formation of more aluminum droplets simultaneously.It is considered that the atomization effect becomes better when atomization pressure is 2.5 MPa,and the nozzle intersection angle is 60°.Industrial tests showed that the aluminum powder prepared by the optimized annular slit atomizer has a finer mean particle size and a higher yield of fine powder.The numerical simulation results agree well with the industrial test data of the powder particle size.