CO2 is a safe natrual refrigerant which had been and will be widely used in air condi-tioning and heat pump systems. The thernodynamic analysis of the CO2 transcritical cycleis presented in this paper. The result show...CO2 is a safe natrual refrigerant which had been and will be widely used in air condi-tioning and heat pump systems. The thernodynamic analysis of the CO2 transcritical cycleis presented in this paper. The result shows that the CO2 cycles offers heat recovery benefitas a heat pump system. It is possible that the COP value of CO2 cycle can compete withthose of R22 or R134a if two stage compression system or an expander system are used.展开更多
Scars are the final result of the four processes that constitute cutaneous wound healing,namely,coagulation,inflammation,proliferation,and remodeling.Permanent scars are produced if the wounds reach the reticular derm...Scars are the final result of the four processes that constitute cutaneous wound healing,namely,coagulation,inflammation,proliferation,and remodeling.Permanent scars are produced if the wounds reach the reticular dermis.The nature of these scars depends on the four wound healing processes.If the remodeling process is excessive,collagen degradation exceeds collagen synthesis and atrophic scars are produced.If the inflammation phase is prolonged and/or more potent for some reason,inflammatory/pathological scars such as keloids or hypertrophic scars can arise.If these pathological scars are located on joints or mobile regions,scar contractures can develop.When used with the appropriate timing and when selected on the basis of individual factors,surgical techniques can improve mature scars.This review paper focuses on the surgical techniques that are used to improve mature scars,burn scars,and scar contractures.Those methods include z-plasties,w-plasties,split-thickness skin grafting,full-thickness skin grafting,local flaps(including the square flap method and the propeller flap),and expanded flaps,distant flaps,regional flaps,and free flaps.展开更多
FLNG(LNG Floating Production Storage and Offloading Unit)液化工艺的关键技术包括液化工艺的选择、晃荡条件下工艺及关键设备的适应性,其对装置的投资、运行稳定性及安全产生很大的影响。根据海上工艺设计标准,对不同液化流程进行比...FLNG(LNG Floating Production Storage and Offloading Unit)液化工艺的关键技术包括液化工艺的选择、晃荡条件下工艺及关键设备的适应性,其对装置的投资、运行稳定性及安全产生很大的影响。根据海上工艺设计标准,对不同液化流程进行比选,分别建造氮膨胀和混合制冷剂两套液化实验装置,并开展晃荡实验,验证工艺及关键设备的海上适应性,实验结果表明:晃荡工况下,丙烷预冷双氮膨胀工艺和双混合制冷剂工艺的液化和处理能力均能保持较高水平,前者适用于处理量小且海况恶劣的海域,后者适用于处理量大且海况平稳的海域;壳侧降膜流动的不稳定性是导致绕管式换热器适应性较板翅式换热器低的主要因素;倾斜和横摇会在较大程度上降低填料塔内液体分布均匀性及传质性能;共振周期直接影响薄膜型液舱的装满度,横摇会提高气液两相分离过程的平衡程度;晃荡对膨胀机工作性能无影响。展开更多
文摘CO2 is a safe natrual refrigerant which had been and will be widely used in air condi-tioning and heat pump systems. The thernodynamic analysis of the CO2 transcritical cycleis presented in this paper. The result shows that the CO2 cycles offers heat recovery benefitas a heat pump system. It is possible that the COP value of CO2 cycle can compete withthose of R22 or R134a if two stage compression system or an expander system are used.
文摘Scars are the final result of the four processes that constitute cutaneous wound healing,namely,coagulation,inflammation,proliferation,and remodeling.Permanent scars are produced if the wounds reach the reticular dermis.The nature of these scars depends on the four wound healing processes.If the remodeling process is excessive,collagen degradation exceeds collagen synthesis and atrophic scars are produced.If the inflammation phase is prolonged and/or more potent for some reason,inflammatory/pathological scars such as keloids or hypertrophic scars can arise.If these pathological scars are located on joints or mobile regions,scar contractures can develop.When used with the appropriate timing and when selected on the basis of individual factors,surgical techniques can improve mature scars.This review paper focuses on the surgical techniques that are used to improve mature scars,burn scars,and scar contractures.Those methods include z-plasties,w-plasties,split-thickness skin grafting,full-thickness skin grafting,local flaps(including the square flap method and the propeller flap),and expanded flaps,distant flaps,regional flaps,and free flaps.
文摘FLNG(LNG Floating Production Storage and Offloading Unit)液化工艺的关键技术包括液化工艺的选择、晃荡条件下工艺及关键设备的适应性,其对装置的投资、运行稳定性及安全产生很大的影响。根据海上工艺设计标准,对不同液化流程进行比选,分别建造氮膨胀和混合制冷剂两套液化实验装置,并开展晃荡实验,验证工艺及关键设备的海上适应性,实验结果表明:晃荡工况下,丙烷预冷双氮膨胀工艺和双混合制冷剂工艺的液化和处理能力均能保持较高水平,前者适用于处理量小且海况恶劣的海域,后者适用于处理量大且海况平稳的海域;壳侧降膜流动的不稳定性是导致绕管式换热器适应性较板翅式换热器低的主要因素;倾斜和横摇会在较大程度上降低填料塔内液体分布均匀性及传质性能;共振周期直接影响薄膜型液舱的装满度,横摇会提高气液两相分离过程的平衡程度;晃荡对膨胀机工作性能无影响。
