We consider a Ginzburg-Landau modified model of layered high-temperature superconductor under pressure. We have theoretically studied the relation between the pressure and the temperature of layered high-temperature s...We consider a Ginzburg-Landau modified model of layered high-temperature superconductor under pressure. We have theoretically studied the relation between the pressure and the temperature of layered high-temperature superconductor. If the pressure is not a constant, we have a relation of quadratic equation between the pressure and the temperature of layered high-temperature superconductor. In a special case, we find the critical temperature decreases with further increasing pressure. In another special ease, the critical temperature increases with further increasing pressure.展开更多
In this study, experiments have been performed for an investigation on heat transfer of water in an inclined downward tube with an inner diameter of 20 mm and an inclined angle of 45° from the horizon, with the r...In this study, experiments have been performed for an investigation on heat transfer of water in an inclined downward tube with an inner diameter of 20 mm and an inclined angle of 45° from the horizon, with the range of pressure from 11.5 to 28 MPa, mass flux from 450 to 1550 kg/(m2 s), and heat flux from 50 to 585 k W/m2. Based on the experimental data, the temperature distribution in the tube wall was derived. The heat transfer characteristics of inclined downward flow were compared with that of vertical downward flow. The effects of heat flux on wall temperature were analyzed and the corresponding empirical correlations were presented. The results show that heat transfer characteristics of water in the inclined downward tube are not uniform along the circumference from the top surface to the bottom surface. An increase in heat flux exacerbates the non-uniformity. At subcritical pressures, both dry-out and departure from nucleate boiling(DNB) occur at the top surface of the inclined downward tube; inversely, only dry-out takes place on the bottom surface of the inclined downward tube and in the vertical downward tube. At near-critical pressures, DNB and dry-out occur in the comparing tubes with greater possibility. At supercritical pressures, heat transfer gets enhanced in the pseudo-critical enthalpy region; in the high enthalpy region, the top surface temperature of the inclined downward tube decreases obviously.展开更多
We investigated the superconducting properties of Fe_(1+y)Te_(0:6)Se_(0:4) single-crystalline microbridges with a width of 4 m and thicknesses ranging from 20.8 to 136.2 nm. The temperature-dependent in-plane resistan...We investigated the superconducting properties of Fe_(1+y)Te_(0:6)Se_(0:4) single-crystalline microbridges with a width of 4 m and thicknesses ranging from 20.8 to 136.2 nm. The temperature-dependent in-plane resistance of the bridges exhibited a type of metalinsulator transition in the normal state. The critical current density(J_c) of the microbridge with a thickness of 136.2 nm was82.3 kA/cm^2 at 3K and reached 105 kA/cm^2 after extrapolation to T = 0 K. The current versus voltage characteristics of the microbridges showed a Josephson-like behavior with an obvious hysteresis. These results demonstrate the potential application of ultra-thin Fe-based microbridges in superconducting electronic devices such as bolometric detectors.展开更多
The voltage-biased current-voltage （I-V） characteristics of intrinsic Josephson junctions （IJJs）, which are fabricated with misa- ligned high temperature superconducting Tl2Ba2CaCu2O8 （T1-2212） thin film, are in...The voltage-biased current-voltage （I-V） characteristics of intrinsic Josephson junctions （IJJs）, which are fabricated with misa- ligned high temperature superconducting Tl2Ba2CaCu2O8 （T1-2212） thin film, are investigated experimentally. Three charac- teristic regions in the I-V curve are observed at 47 K. In the low voltage part, the current firstly increases and then decreases slowly with increasing the biased voltage, which is shown as a bump. In the next region, the current slightly increases with in- creasing the biased voltage until a sudden decrease of the current appears. Thereafter, branch structure forms with increasing the voltage on the I-V characteristic. The influence of the self-heating on the I-V characteristics is investigated and the temper- ature dependence of the I-V characteristics is measured to explore these characteristics in detail.展开更多
文摘We consider a Ginzburg-Landau modified model of layered high-temperature superconductor under pressure. We have theoretically studied the relation between the pressure and the temperature of layered high-temperature superconductor. If the pressure is not a constant, we have a relation of quadratic equation between the pressure and the temperature of layered high-temperature superconductor. In a special case, we find the critical temperature decreases with further increasing pressure. In another special ease, the critical temperature increases with further increasing pressure.
基金supported by the "Strategic Priority Research Program" Demonstration of Key Technologies for Clean and Efficient Utilization of Low-rank Coal (Grant No. XDA07030100)
文摘In this study, experiments have been performed for an investigation on heat transfer of water in an inclined downward tube with an inner diameter of 20 mm and an inclined angle of 45° from the horizon, with the range of pressure from 11.5 to 28 MPa, mass flux from 450 to 1550 kg/(m2 s), and heat flux from 50 to 585 k W/m2. Based on the experimental data, the temperature distribution in the tube wall was derived. The heat transfer characteristics of inclined downward flow were compared with that of vertical downward flow. The effects of heat flux on wall temperature were analyzed and the corresponding empirical correlations were presented. The results show that heat transfer characteristics of water in the inclined downward tube are not uniform along the circumference from the top surface to the bottom surface. An increase in heat flux exacerbates the non-uniformity. At subcritical pressures, both dry-out and departure from nucleate boiling(DNB) occur at the top surface of the inclined downward tube; inversely, only dry-out takes place on the bottom surface of the inclined downward tube and in the vertical downward tube. At near-critical pressures, DNB and dry-out occur in the comparing tubes with greater possibility. At supercritical pressures, heat transfer gets enhanced in the pseudo-critical enthalpy region; in the high enthalpy region, the top surface temperature of the inclined downward tube decreases obviously.
基金supported by the National Natural Science Foundation of China(Grant Nos.11234006,61501220,U1432135,11674054,and 11611140101)Jiangsu Provincial Natural Science Fund(Grant No.SBK2015040804)Opening Project of Wuhan National High Magnetic Field Center(Grant No.2015KF19)
文摘We investigated the superconducting properties of Fe_(1+y)Te_(0:6)Se_(0:4) single-crystalline microbridges with a width of 4 m and thicknesses ranging from 20.8 to 136.2 nm. The temperature-dependent in-plane resistance of the bridges exhibited a type of metalinsulator transition in the normal state. The critical current density(J_c) of the microbridge with a thickness of 136.2 nm was82.3 kA/cm^2 at 3K and reached 105 kA/cm^2 after extrapolation to T = 0 K. The current versus voltage characteristics of the microbridges showed a Josephson-like behavior with an obvious hysteresis. These results demonstrate the potential application of ultra-thin Fe-based microbridges in superconducting electronic devices such as bolometric detectors.
基金supported by the National Natural Science Foundation of China(Grant Nos.61176119,61171028,51002081 and 61101018)
文摘The voltage-biased current-voltage （I-V） characteristics of intrinsic Josephson junctions （IJJs）, which are fabricated with misa- ligned high temperature superconducting Tl2Ba2CaCu2O8 （T1-2212） thin film, are investigated experimentally. Three charac- teristic regions in the I-V curve are observed at 47 K. In the low voltage part, the current firstly increases and then decreases slowly with increasing the biased voltage, which is shown as a bump. In the next region, the current slightly increases with in- creasing the biased voltage until a sudden decrease of the current appears. Thereafter, branch structure forms with increasing the voltage on the I-V characteristic. The influence of the self-heating on the I-V characteristics is investigated and the temper- ature dependence of the I-V characteristics is measured to explore these characteristics in detail.
