该文分析了膨胀石墨双极板(EGBPs)各向异性结构对燃料电池水热管理与输出性能的影响。建立了三维两相非等温数值模型,对比了4种典型复合材料结构下温度、电流密度、水含量等参数的分布特征,揭示了双极板传热特性与输出性能的耦合效应。...该文分析了膨胀石墨双极板(EGBPs)各向异性结构对燃料电池水热管理与输出性能的影响。建立了三维两相非等温数值模型,对比了4种典型复合材料结构下温度、电流密度、水含量等参数的分布特征,揭示了双极板传热特性与输出性能的耦合效应。结果表明:沿质子传递方向热导率(k_z)对燃料电池性能具有显著影响,在2.2 A cm^(-2)电流密度下,将k_z从常规结构的5 W·m^(-1)·K^(-1)提升至280 W·m^(-1)·K^(-1),可以使输出性能提高22 m V;沿流道气体流动方向的热导率(k_y)是影响散热能力的关键因素,将k_y与k_z提高至280 W·m^(-1)·K^(-1),或者实现各向同性结构(k_x=k_y=k_z=20 W·m^(-1)·K^(-1)),均能够使膜电极组件(MEA)核心区域的温度降低2℃左右。因此,提高k_y与k_z并实现各向同性结构是膨胀石墨双极板技术的未来发展目标之一。展开更多
Large tarsal plate defect reconstruction is one of the most challenging tasks for plastic surgeons.Based on our practical work and literature review,the techniques and postoperative results of the preserved sclera,ear...Large tarsal plate defect reconstruction is one of the most challenging tasks for plastic surgeons.Based on our practical work and literature review,the techniques and postoperative results of the preserved sclera,ear cartilage,and acellular dermal matrix(ADM)as tarsal plate substitutes were investigated.Two cases were reviewed.Case 1 was a 22-year-old female who had total loss of the right lower eyelid.Ear cartilage(23 mm25 mm)was implanted under the expanded skin during the forehead skin-expanding procedure to form a skin-cartilageexpander capsule compound structure for lower eyelid reconstruction.Case 2 was a 7-year-old boy with a unilateral divided nevus.The lid and conjunctiva of the lower eyelid were invaded.A piece of ADM(12 mm4 mm)was used to repair the tarsal plate defect(12 mm3 mm).The conjunctiva of ADM was covered by itself.An orbicularis oculi myocutaneous flap was used for anterior lamella reconstruction.In case 1,the compound tissue survived and supported the lower eyelid,the lid margin was clear,and the structure was complete over a 1-year follow-up.The aesthetic appearance of the eyelid improved after depilation.It is the first clinical research on the expander capsule as eyelid conjunctiva.In case 2,the conjunctiva completely covered the superior ADM,and the transplant merged with the surrounding tissues without complications after 5 months.The preserved sclera has the longest application history as a tarsal plate substitute.However,it should be preserved in an eye bank and transplanted with conjunctiva repair.Ear cartilage is an autologous tissue that requires conjunctival reconstruction.Our clinical practice was the first to prove the possibility of the expander capsule as eyelid conjunctiva.It is feasible to prefabricate the skin-tarsal conjunctiva complex during the skin expansion procedure.Allogeneic ADM is a common clinical material with advantages of good biological histocompatibility,supportive strength,conjunctivalization,and not requiring donor site surgery.Plastic surgeons are familiar with autologous ear cartilage and ADM,which are easy to obtain and treat.Both ear cartilage and ADM are expected to be the first-line choices in future studies.展开更多
With increasing awareness of energy conservation and environmental protection, the Organic Rankine Cycle (ORC) system has gained significant attention. This technology enables the recovery of industrial waste heat, wa...With increasing awareness of energy conservation and environmental protection, the Organic Rankine Cycle (ORC) system has gained significant attention. This technology enables the recovery of industrial waste heat, waste incineration heat, and renewable energy sources such as geothermal heat, biomass energy, and solar energy at lower temperatures. However, the low-grade heat source utilized in ORC systems faces a challenge to achieving high power generation efficiency and output power. Therefore, enhancing the power generation capacity of ORC systems is a key research focus in this field. An entranced heat exchanger ORC system with the screw expander driven by the low-temperature heat source is established to investigate the relevant performance. Hot water temperature from 77°C to 132°C is adopted for performance analysis, while the environmental temperature is approximately 25°C. Refrigerant R245fa is selected as the working fluid, and the screw expander is employed for power generation. It is worth noting that the entranced heat exchanger ORC system has significant potential for low-temperature heat recovery. Experimental results indicate that the maximum power output is 12.83 kW, which is obtained at around 105°C hot water inlet temperature. Correspondingly, the average power output remains 11.75 kW, revealing the system’s high stability for power generation. The implementation of a plate heat exchanger for enhanced heat transfer has enabled a 50% reduction in system size compared to traditional shell-tube type ORC systems. Besides, economic calculations demonstrate substantial benefits associated with the ORC system. The calculations indicate an internal benefit of 560,000 RMB/year, accompanied by notable external benefits such as an energy saving and emission reduction potential of up to 784 t CO2 per year. Moreover, the payback period is 2.23 years. It shows a remarkable improvement in terms of performance and excellent economic benefits. As a result, the novel ORC presents a promising alternative for low-grade heat utilization as compared to conventional small-scale ORC systems.展开更多
文摘该文分析了膨胀石墨双极板(EGBPs)各向异性结构对燃料电池水热管理与输出性能的影响。建立了三维两相非等温数值模型,对比了4种典型复合材料结构下温度、电流密度、水含量等参数的分布特征,揭示了双极板传热特性与输出性能的耦合效应。结果表明:沿质子传递方向热导率(k_z)对燃料电池性能具有显著影响,在2.2 A cm^(-2)电流密度下,将k_z从常规结构的5 W·m^(-1)·K^(-1)提升至280 W·m^(-1)·K^(-1),可以使输出性能提高22 m V;沿流道气体流动方向的热导率(k_y)是影响散热能力的关键因素,将k_y与k_z提高至280 W·m^(-1)·K^(-1),或者实现各向同性结构(k_x=k_y=k_z=20 W·m^(-1)·K^(-1)),均能够使膜电极组件(MEA)核心区域的温度降低2℃左右。因此,提高k_y与k_z并实现各向同性结构是膨胀石墨双极板技术的未来发展目标之一。
基金the Shanghai Committee of Science and Technology,China(grant no.19ZR1430100)。
文摘Large tarsal plate defect reconstruction is one of the most challenging tasks for plastic surgeons.Based on our practical work and literature review,the techniques and postoperative results of the preserved sclera,ear cartilage,and acellular dermal matrix(ADM)as tarsal plate substitutes were investigated.Two cases were reviewed.Case 1 was a 22-year-old female who had total loss of the right lower eyelid.Ear cartilage(23 mm25 mm)was implanted under the expanded skin during the forehead skin-expanding procedure to form a skin-cartilageexpander capsule compound structure for lower eyelid reconstruction.Case 2 was a 7-year-old boy with a unilateral divided nevus.The lid and conjunctiva of the lower eyelid were invaded.A piece of ADM(12 mm4 mm)was used to repair the tarsal plate defect(12 mm3 mm).The conjunctiva of ADM was covered by itself.An orbicularis oculi myocutaneous flap was used for anterior lamella reconstruction.In case 1,the compound tissue survived and supported the lower eyelid,the lid margin was clear,and the structure was complete over a 1-year follow-up.The aesthetic appearance of the eyelid improved after depilation.It is the first clinical research on the expander capsule as eyelid conjunctiva.In case 2,the conjunctiva completely covered the superior ADM,and the transplant merged with the surrounding tissues without complications after 5 months.The preserved sclera has the longest application history as a tarsal plate substitute.However,it should be preserved in an eye bank and transplanted with conjunctiva repair.Ear cartilage is an autologous tissue that requires conjunctival reconstruction.Our clinical practice was the first to prove the possibility of the expander capsule as eyelid conjunctiva.It is feasible to prefabricate the skin-tarsal conjunctiva complex during the skin expansion procedure.Allogeneic ADM is a common clinical material with advantages of good biological histocompatibility,supportive strength,conjunctivalization,and not requiring donor site surgery.Plastic surgeons are familiar with autologous ear cartilage and ADM,which are easy to obtain and treat.Both ear cartilage and ADM are expected to be the first-line choices in future studies.
文摘With increasing awareness of energy conservation and environmental protection, the Organic Rankine Cycle (ORC) system has gained significant attention. This technology enables the recovery of industrial waste heat, waste incineration heat, and renewable energy sources such as geothermal heat, biomass energy, and solar energy at lower temperatures. However, the low-grade heat source utilized in ORC systems faces a challenge to achieving high power generation efficiency and output power. Therefore, enhancing the power generation capacity of ORC systems is a key research focus in this field. An entranced heat exchanger ORC system with the screw expander driven by the low-temperature heat source is established to investigate the relevant performance. Hot water temperature from 77°C to 132°C is adopted for performance analysis, while the environmental temperature is approximately 25°C. Refrigerant R245fa is selected as the working fluid, and the screw expander is employed for power generation. It is worth noting that the entranced heat exchanger ORC system has significant potential for low-temperature heat recovery. Experimental results indicate that the maximum power output is 12.83 kW, which is obtained at around 105°C hot water inlet temperature. Correspondingly, the average power output remains 11.75 kW, revealing the system’s high stability for power generation. The implementation of a plate heat exchanger for enhanced heat transfer has enabled a 50% reduction in system size compared to traditional shell-tube type ORC systems. Besides, economic calculations demonstrate substantial benefits associated with the ORC system. The calculations indicate an internal benefit of 560,000 RMB/year, accompanied by notable external benefits such as an energy saving and emission reduction potential of up to 784 t CO2 per year. Moreover, the payback period is 2.23 years. It shows a remarkable improvement in terms of performance and excellent economic benefits. As a result, the novel ORC presents a promising alternative for low-grade heat utilization as compared to conventional small-scale ORC systems.
