Nowadays, Autonomous Underwater Vehicles(AUVs) are frequently used for exploring the oceans. The hydrodynamics of AUVs moving in the vicinity of the water surface are significantly different at higher depths. In this ...Nowadays, Autonomous Underwater Vehicles(AUVs) are frequently used for exploring the oceans. The hydrodynamics of AUVs moving in the vicinity of the water surface are significantly different at higher depths. In this paper, the hydrodynamic coefficients of an AUV in non-dimensional depths of 0.75, 1, 1.5, 2, and 4D are obtained for movement close to the free-surface. Reynolds Averaged Navier Stokes Equations(RANS) are discretized using the finite volume approach and the water-surface effects modeled using the Volume of Fraction(VOF) method. As the operating speeds of AUVs are usually low, the boundary layer over them is not fully laminar or fully turbulent, so the effect of boundary layer transition from laminar to turbulent flow was considered in the simulations. Two different turbulence/transition models were used: 1) a full-turbulence model, the k-ε model, and 2) a turbulence/transition model, Menter's Transition-SST model. The results show that the Menter's Transition-SST model has a better consistency with experimental results. In addition, the wave-making effects of these bodies are studied at different immersion depths in the sea-surface vicinity or at finite depths. It is observed that the relevant pitch moments and lift coefficients are non-zero for these axi-symmetric bodies when they move close to the sea-surface. This is not expected for greater depths.展开更多
An entanglement purification protocol for mixed entangled states is presented via double quantum dot molecules inside a superconducing transmission line resonator （TLR）. In the current scenario, coupling for arbitra...An entanglement purification protocol for mixed entangled states is presented via double quantum dot molecules inside a superconducing transmission line resonator （TLR）. In the current scenario, coupling for arbitrary double quantum dot molecules can be tuned via the TLR in the large detuning region by controlling the qubit level splitting. The TLR is always empty and only virtually excited, so the interaction is insensitive to both the TLR decay and thermal field. Discussion about the feasibility of our scheme shows that the entanglement purification can be implemented with high fidelity and successful probability.展开更多
Objectives To evaluate the anti- ischemic effect of ISDN on the patients with coronary heart disease . The change in the size of the defect area as percentage of the entire myocardium as determined by the unfolded sur...Objectives To evaluate the anti- ischemic effect of ISDN on the patients with coronary heart disease . The change in the size of the defect area as percentage of the entire myocardium as determined by the unfolded surface mapping between the baseline and after ISDN infusion reflects the anti-ischemic effect of ISDN. Methods and Results 99m Tc-MIBI myocardial perfusion SPECT images were acquired, and reconstruction of the bull's eye map and unfolded surface mapping were performed according to the dates of tomography images. In the group (99mTc-MIBI was injected at 30 minutes after the start of ISDN iv drip) : at the 65% threshold value, the percentage of the defect area size in the whole ventricle was 33.01 ± 5.35% at baseline, (28.9 ±5.23)% after ISDN was infused (P < 0.05); at the 55% threshold value, the percentage of the defect area size in the whole ventricle was (22.06±5.58)% at baseline, (19.60±4.07)% after ISDN was infused (P < 0.05); the sum of defect blood ST segments is 60 at baseline, 51 after ISDN was infused. In the group (99mTc-MIBI was injected at 60 minutes after the start of ISDN iv drip): at the 65% threshold value, the percentage of the defect area size in the whole ventricle was (29.20±5.08)% at baseline, (20.81±4.16)% after ISDN was infused (P < 0.001); at the 55% threshold value, the percentage of the defect area size in the whole ventricle was (21.2 ± 5.49)% at baseline, (17.52±5.59)% after ISDN was infused (P < 0.001); the sum of defect blood ST segments is 58 at baseline, 47 after ISDN was infused. In the group (99mTc-MIBI was injected at 150 minutes after the start of ISDN iv drip) : at the 65% threshold value, the percentage of the defect area size in the whole ventricle was (32.87 ±6.46)% at baseline, (20.81±4.16)% after ISDN was infused (P < 0.001); at the 55% threshold value, the percentage of the defect area size in the whole ventricle was (18.42± 5.17)% at baseline, (14.18±3.61)% after ISDN was infused (P< 0.001); the sum of defect blood ST segments was 64 at baseline, 41 after ISDN was infused. Conclusions The unfolded surface mapping of 99mTc- MIBI myocardial perfusion image can be used as a method of quantitatively evaluating the anti-ischemic effect of drugs and ISDN iv drip can improve the blood flow in myocardium (myocardium perfusion).展开更多
文摘Nowadays, Autonomous Underwater Vehicles(AUVs) are frequently used for exploring the oceans. The hydrodynamics of AUVs moving in the vicinity of the water surface are significantly different at higher depths. In this paper, the hydrodynamic coefficients of an AUV in non-dimensional depths of 0.75, 1, 1.5, 2, and 4D are obtained for movement close to the free-surface. Reynolds Averaged Navier Stokes Equations(RANS) are discretized using the finite volume approach and the water-surface effects modeled using the Volume of Fraction(VOF) method. As the operating speeds of AUVs are usually low, the boundary layer over them is not fully laminar or fully turbulent, so the effect of boundary layer transition from laminar to turbulent flow was considered in the simulations. Two different turbulence/transition models were used: 1) a full-turbulence model, the k-ε model, and 2) a turbulence/transition model, Menter's Transition-SST model. The results show that the Menter's Transition-SST model has a better consistency with experimental results. In addition, the wave-making effects of these bodies are studied at different immersion depths in the sea-surface vicinity or at finite depths. It is observed that the relevant pitch moments and lift coefficients are non-zero for these axi-symmetric bodies when they move close to the sea-surface. This is not expected for greater depths.
基金Supported by the National Natural Science Foundation of China under Grant Nos 60678022 and 10704001, the Specialized Research Pund for the Doctoral Program of Higher Education under Grant No 20060357008, the Key Program of the Education Department of Anhui Province under Grant Nos KJ2009A048Z, the Talent Project of the Anhui Province for Outstanding Youth under Grant Nos 2010SQRL153ZD and 2010SQRL187.
文摘An entanglement purification protocol for mixed entangled states is presented via double quantum dot molecules inside a superconducing transmission line resonator （TLR）. In the current scenario, coupling for arbitrary double quantum dot molecules can be tuned via the TLR in the large detuning region by controlling the qubit level splitting. The TLR is always empty and only virtually excited, so the interaction is insensitive to both the TLR decay and thermal field. Discussion about the feasibility of our scheme shows that the entanglement purification can be implemented with high fidelity and successful probability.
文摘Objectives To evaluate the anti- ischemic effect of ISDN on the patients with coronary heart disease . The change in the size of the defect area as percentage of the entire myocardium as determined by the unfolded surface mapping between the baseline and after ISDN infusion reflects the anti-ischemic effect of ISDN. Methods and Results 99m Tc-MIBI myocardial perfusion SPECT images were acquired, and reconstruction of the bull's eye map and unfolded surface mapping were performed according to the dates of tomography images. In the group (99mTc-MIBI was injected at 30 minutes after the start of ISDN iv drip) : at the 65% threshold value, the percentage of the defect area size in the whole ventricle was 33.01 ± 5.35% at baseline, (28.9 ±5.23)% after ISDN was infused (P < 0.05); at the 55% threshold value, the percentage of the defect area size in the whole ventricle was (22.06±5.58)% at baseline, (19.60±4.07)% after ISDN was infused (P < 0.05); the sum of defect blood ST segments is 60 at baseline, 51 after ISDN was infused. In the group (99mTc-MIBI was injected at 60 minutes after the start of ISDN iv drip): at the 65% threshold value, the percentage of the defect area size in the whole ventricle was (29.20±5.08)% at baseline, (20.81±4.16)% after ISDN was infused (P < 0.001); at the 55% threshold value, the percentage of the defect area size in the whole ventricle was (21.2 ± 5.49)% at baseline, (17.52±5.59)% after ISDN was infused (P < 0.001); the sum of defect blood ST segments is 58 at baseline, 47 after ISDN was infused. In the group (99mTc-MIBI was injected at 150 minutes after the start of ISDN iv drip) : at the 65% threshold value, the percentage of the defect area size in the whole ventricle was (32.87 ±6.46)% at baseline, (20.81±4.16)% after ISDN was infused (P < 0.001); at the 55% threshold value, the percentage of the defect area size in the whole ventricle was (18.42± 5.17)% at baseline, (14.18±3.61)% after ISDN was infused (P< 0.001); the sum of defect blood ST segments was 64 at baseline, 41 after ISDN was infused. Conclusions The unfolded surface mapping of 99mTc- MIBI myocardial perfusion image can be used as a method of quantitatively evaluating the anti-ischemic effect of drugs and ISDN iv drip can improve the blood flow in myocardium (myocardium perfusion).
