In multiphase pumps transporting gas-liquid two-phase flows,the high-speed rotation of the impeller induces complex deformations in bubble shapes within the flow domain,making the prediction of gasliquid two-phase dra...In multiphase pumps transporting gas-liquid two-phase flows,the high-speed rotation of the impeller induces complex deformations in bubble shapes within the flow domain,making the prediction of gasliquid two-phase drag forces highly challenging in numerical simulations.To achieve precise prediction of the drag forces on irregular bubbles within multiphase pumps,this study modifies the existing bubble drag force model and applies the revised model to the prediction of gas-liquid two-phase flow within multiphase pumps.The research findings indicate that the modified drag force model significantly enhances the accuracy of predicting flow characteristics within the pump,particularly under high gas volume fraction conditions.The simulation results for gas phase distribution and vorticity exhibit strong agreement with experimental data.The modified drag model better captures the accumulation of the gas phase at the suction side of the impeller outlet.It also accurately predicts the vortex characteristics induced by bubble backflow from the trailing edges of the diffuser.Additionally,the adjustment of the drag coefficient enhances the model’s ability to represent local flow field characteristics,thereby optimizing the performance simulation methods of multiphase pumps.Compared to traditional drag force models,the modified model reduces prediction errors in head and efficiency by 36.4%and 27.5%,respectively.These results provide important theoretical foundations and model support for improving the accuracy of gas-liquid two-phase flow simulations and optimizing the design of multiphase pumps under high gas volume fraction conditions.展开更多
An optimized device structure for reducing the RESET current of phase-change random access memory （PCRAM） with blade-type like （BTL） phase change layer is proposed. The electrical thermal analysis of the BTL cell ...An optimized device structure for reducing the RESET current of phase-change random access memory （PCRAM） with blade-type like （BTL） phase change layer is proposed. The electrical thermal analysis of the BTL cell and the blade heater contactor structure by three-dimensional finite element modeling are compared with each other during RESET operation. The simulation results show that the programming region of the phase change layer in the BTL cell is much smaller, and thermal electrical distributions of the BTL cell are more concentrated on the TiN/GST interface. The results indicate that the BTL cell has the superiorities of increasing the heating efficiency, decreasing the power consumption and reducing the RESET current from 0.67mA to 0.32mA. Therefore, the BTL cell will be appropriate for high performance PCRAM device with lower power consumption and lower RESET current.展开更多
目的探究火龙罐联合刃针在寒湿型腰肌劳损治疗中的应用效果。方法将2024年5月—2025年5月洛阳正骨医院收治的120例确诊为寒湿型腰肌劳损的患者按随机分配原则分成两组,每组60例。对照组实施刃针治疗,观察组实施刃针联合火龙罐治疗,为期...目的探究火龙罐联合刃针在寒湿型腰肌劳损治疗中的应用效果。方法将2024年5月—2025年5月洛阳正骨医院收治的120例确诊为寒湿型腰肌劳损的患者按随机分配原则分成两组,每组60例。对照组实施刃针治疗,观察组实施刃针联合火龙罐治疗,为期4周。治疗结束后,综合评估两组患者的临床疗效,包括对(visual analog scale,VAS)评分、(oswestry disability index,ODI)评分及(36-Item Short Form Health Survey,SF-36)评分的数据对比,以全面评价疗效和生理指标的改善情况。结果在完成治疗周期后,两组受试者的VAS评分、ODI评分及SF-36评分相较于治疗前均呈现出显著改善(P<0.05)。进一步分析发现,观察组在上述指标的改善程度上均显著优于对照组(P<0.05)。此外,观察组的临床治疗有效率91.67%,显著高于对照组的78.33%(P<0.05)。结论火龙罐联合刃针对治疗寒湿型腰肌劳损效果显著。此方法不仅能显著改善患者的疼痛和腰椎活动功能指标,还能有效提升患者的日常生活质量,显示出其在临床应用中的优越性和潜在价值。展开更多
基金funded by Sichuan Natural Science Foundation Outstanding Youth Science Foundation(No.2024NSFJQ0012)Key project of Regional Innovation and Development Joint Fund of National Natural Science Foundation(No.U23A20669)Sichuan Science and Technology Program(2022ZDZX0041).
文摘In multiphase pumps transporting gas-liquid two-phase flows,the high-speed rotation of the impeller induces complex deformations in bubble shapes within the flow domain,making the prediction of gasliquid two-phase drag forces highly challenging in numerical simulations.To achieve precise prediction of the drag forces on irregular bubbles within multiphase pumps,this study modifies the existing bubble drag force model and applies the revised model to the prediction of gas-liquid two-phase flow within multiphase pumps.The research findings indicate that the modified drag force model significantly enhances the accuracy of predicting flow characteristics within the pump,particularly under high gas volume fraction conditions.The simulation results for gas phase distribution and vorticity exhibit strong agreement with experimental data.The modified drag model better captures the accumulation of the gas phase at the suction side of the impeller outlet.It also accurately predicts the vortex characteristics induced by bubble backflow from the trailing edges of the diffuser.Additionally,the adjustment of the drag coefficient enhances the model’s ability to represent local flow field characteristics,thereby optimizing the performance simulation methods of multiphase pumps.Compared to traditional drag force models,the modified model reduces prediction errors in head and efficiency by 36.4%and 27.5%,respectively.These results provide important theoretical foundations and model support for improving the accuracy of gas-liquid two-phase flow simulations and optimizing the design of multiphase pumps under high gas volume fraction conditions.
基金Supported by the Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No XDA09020402the National Integrate Circuit Research Program of China under Grant No 2009ZX02023-003+1 种基金the National Natural Science Foundation of China under Grant Nos 61261160500,61376006,61401444 and 61504157the Science and Technology Council of Shanghai under Grant Nos 14DZ2294900,15DZ2270900 and 14ZR1447500
文摘An optimized device structure for reducing the RESET current of phase-change random access memory （PCRAM） with blade-type like （BTL） phase change layer is proposed. The electrical thermal analysis of the BTL cell and the blade heater contactor structure by three-dimensional finite element modeling are compared with each other during RESET operation. The simulation results show that the programming region of the phase change layer in the BTL cell is much smaller, and thermal electrical distributions of the BTL cell are more concentrated on the TiN/GST interface. The results indicate that the BTL cell has the superiorities of increasing the heating efficiency, decreasing the power consumption and reducing the RESET current from 0.67mA to 0.32mA. Therefore, the BTL cell will be appropriate for high performance PCRAM device with lower power consumption and lower RESET current.
文摘目的探究火龙罐联合刃针在寒湿型腰肌劳损治疗中的应用效果。方法将2024年5月—2025年5月洛阳正骨医院收治的120例确诊为寒湿型腰肌劳损的患者按随机分配原则分成两组,每组60例。对照组实施刃针治疗,观察组实施刃针联合火龙罐治疗,为期4周。治疗结束后,综合评估两组患者的临床疗效,包括对(visual analog scale,VAS)评分、(oswestry disability index,ODI)评分及(36-Item Short Form Health Survey,SF-36)评分的数据对比,以全面评价疗效和生理指标的改善情况。结果在完成治疗周期后,两组受试者的VAS评分、ODI评分及SF-36评分相较于治疗前均呈现出显著改善(P<0.05)。进一步分析发现,观察组在上述指标的改善程度上均显著优于对照组(P<0.05)。此外,观察组的临床治疗有效率91.67%,显著高于对照组的78.33%(P<0.05)。结论火龙罐联合刃针对治疗寒湿型腰肌劳损效果显著。此方法不仅能显著改善患者的疼痛和腰椎活动功能指标,还能有效提升患者的日常生活质量,显示出其在临床应用中的优越性和潜在价值。
