Entangled porous metallic wire material(EPMWM)has the potential as a thermal insulation material in defence and engineering.In order to optimize its thermophysical properties at the design stage,it is of great signifi...Entangled porous metallic wire material(EPMWM)has the potential as a thermal insulation material in defence and engineering.In order to optimize its thermophysical properties at the design stage,it is of great significance to reveal the thermal response mechanism of EPMWM based on its complex structural effects.In the present work,virtual manufacturing technology(VMT)was developed to restore the physics-based 3D model of EPMWM.On this basis,the transient thermal analysis is carried out to explore the contact-relevant thermal behavior of EPMWM,and then the spiral unit containing unique structural information are further extracted and counted.In particular,the thermal resistance network is numerically constructed based on the spiral unit through the thermoelectric analogy method to accurately predict the effective thermal conductivity(ETC)of EPMWM.Finally,the thermal diffusivity and specific heat of the samples were obtained by the laser thermal analyzer to calculate the ETC and thermal insulation factor of interest.The results show that the ETC of EPMWM increases with increasing temperature or reducing density under the experimental conditions.The numerical prediction is consistent with the experimental result and the average error is less than 4%.展开更多
目的通过分析比较非糜烂性反流病(NERD)、反流高敏感(RH)和功能性烧心(FH)患者的食管24 h pH-阻抗监测反流模式,探讨内镜阴性烧心患者症状可能的发生机制。方法选取我院消化科门诊和胃肠功能室的以烧心为主要症状的患者,通过胃镜、24 h ...目的通过分析比较非糜烂性反流病(NERD)、反流高敏感(RH)和功能性烧心(FH)患者的食管24 h pH-阻抗监测反流模式,探讨内镜阴性烧心患者症状可能的发生机制。方法选取我院消化科门诊和胃肠功能室的以烧心为主要症状的患者,通过胃镜、24 h pH-阻抗监测,最终纳入79例患者,包括NERD 35例,RH 16例和FH 28例,进行pH-阻抗数据分析。结果NERD组较RH组、FH组酸反流次数显著性增加、弱碱反流次数显著性减少,差异有统计学意义(P均<0.05);NERD组、RH组合计反流次数、混合反流次数、近端酸反流次数及百分比、近端弱酸反流次数及百分比、近端合计反流次数及百分比较FH组显著性增加,差异有统计学意义(P均<0.05);分析反流的酸度,NERD、RH和FH三组中各种反流所占的比例之间差异有统计学意义(P<0.05),在NERD组以酸反流为主,但在RH和FH组,则以弱酸反流为主,且弱碱反流也较NERD组显著性增加。结论NERD患者与RH患者、FH患者反流模式不同,前者以酸反流为主,后两者弱碱反流明显增多;对于pH-阻抗监测期间无症状或未记录症状的食管酸暴露正常患者,合计反流次数、混合反流次数、近端反流次数及百分比等阻抗监测指标将有助于鉴别RH和FH。展开更多
基金National Natural Science Foundation of China(Grant Nos.52175162,51805086 and 51975123)Natural Science Foundation of Fujian Province,China(Grant No.2019J01210)Health Education Joint Project of Fujian Province,China(Grant No.2019-WJ-01).
文摘Entangled porous metallic wire material(EPMWM)has the potential as a thermal insulation material in defence and engineering.In order to optimize its thermophysical properties at the design stage,it is of great significance to reveal the thermal response mechanism of EPMWM based on its complex structural effects.In the present work,virtual manufacturing technology(VMT)was developed to restore the physics-based 3D model of EPMWM.On this basis,the transient thermal analysis is carried out to explore the contact-relevant thermal behavior of EPMWM,and then the spiral unit containing unique structural information are further extracted and counted.In particular,the thermal resistance network is numerically constructed based on the spiral unit through the thermoelectric analogy method to accurately predict the effective thermal conductivity(ETC)of EPMWM.Finally,the thermal diffusivity and specific heat of the samples were obtained by the laser thermal analyzer to calculate the ETC and thermal insulation factor of interest.The results show that the ETC of EPMWM increases with increasing temperature or reducing density under the experimental conditions.The numerical prediction is consistent with the experimental result and the average error is less than 4%.
文摘目的通过分析比较非糜烂性反流病(NERD)、反流高敏感(RH)和功能性烧心(FH)患者的食管24 h pH-阻抗监测反流模式,探讨内镜阴性烧心患者症状可能的发生机制。方法选取我院消化科门诊和胃肠功能室的以烧心为主要症状的患者,通过胃镜、24 h pH-阻抗监测,最终纳入79例患者,包括NERD 35例,RH 16例和FH 28例,进行pH-阻抗数据分析。结果NERD组较RH组、FH组酸反流次数显著性增加、弱碱反流次数显著性减少,差异有统计学意义(P均<0.05);NERD组、RH组合计反流次数、混合反流次数、近端酸反流次数及百分比、近端弱酸反流次数及百分比、近端合计反流次数及百分比较FH组显著性增加,差异有统计学意义(P均<0.05);分析反流的酸度,NERD、RH和FH三组中各种反流所占的比例之间差异有统计学意义(P<0.05),在NERD组以酸反流为主,但在RH和FH组,则以弱酸反流为主,且弱碱反流也较NERD组显著性增加。结论NERD患者与RH患者、FH患者反流模式不同,前者以酸反流为主,后两者弱碱反流明显增多;对于pH-阻抗监测期间无症状或未记录症状的食管酸暴露正常患者,合计反流次数、混合反流次数、近端反流次数及百分比等阻抗监测指标将有助于鉴别RH和FH。
