Internal and external wall surface temperatures (Tws) in April, August and December in Kunming, a city in low latitude plateau, were investigated. Results showed that the Tws in April were of the highest among the thr...Internal and external wall surface temperatures (Tws) in April, August and December in Kunming, a city in low latitude plateau, were investigated. Results showed that the Tws in April were of the highest among the three, followed by August and December. The Tws differences among walls with different orientation were higher in April and December when the weather tends to be sunny, and lower in August with more cloudy days in the time. In April and August, Tws of E-wall was the highest, followed by S- and N-wall. But in December Tws of S-wall might be sometimes higher than E one. Diurnal range of internal Tws was usually smaller than that of the external, with also a time lag for the occurrence of its maximum and minimum. The results can serve as a basis for further research on building microclimate and urban architecture designs. It also gives suggestions for similar studies in other areas.展开更多
The receiver is an important element in solar energy plants.The principal receiver’s tubes in power plants are devised to work under extremely severe conditions,including excessive heat fluxes.Half of the tube’s cir...The receiver is an important element in solar energy plants.The principal receiver’s tubes in power plants are devised to work under extremely severe conditions,including excessive heat fluxes.Half of the tube’s circumference is heated whilst the other half is insulated.This study aims to improve the heat transfer process and reinforce the tubes’structure by designing a new receiver;by including longitudinal fins of triangular,circular and square shapes.The research is conducted experimentally using Reynolds numbers ranging from 28,000 to 78,000.Triangular fins have demonstrated the best improvement for heat transfer.For Reynolds number value near 43,000 Nusselt number(Nu)is higher by 3.5%and 7.5%,sequentially,compared to circular and square tube fins,but varies up to 6.5%near Re=61000.The lowest friction factor is seen in a triangular fin receiver;where it deviates from circular fins by 4.6%,and square fin tubes by 3.2%.Adding fins makes the temperature decrease gradually,and in the case of no fins,the temperature gradient between the hot tube and water drops sharply in the planed tube by 7%.展开更多
Objective To study the redistribution of ET1 receptors in two subcellular organelles, the sarcolemmal membrane and the light vesicle, of rat heart during the progress of septic shock Methods Male Sprague Dawley ...Objective To study the redistribution of ET1 receptors in two subcellular organelles, the sarcolemmal membrane and the light vesicle, of rat heart during the progress of septic shock Methods Male Sprague Dawley rats weighing from 270 to 320?g were randomly divided into three groups: control, early sepsis, and late sepsis Each group included six rats Sepsis was induced by cecal ligation and puncture (CLP) Control rats were sham operated After operation for 9 hours or 18 hours, animals of the three groups were anesthetized with sodium pentobarbital (60?mg/kg IP) and the hearts were removed for preparation of sarcolemma and light vesicle Hemodynamic parameters were determined with polygraph via femoral artery and intraventricular cannula ET1 receptor was assayed by [ 125 I] ET1 binding Results Heart rate, cardiac output and left ventricular +dp/dt max undergo biphasic changes: an increase in early phase of sepsis (9?h after CLP) followed by a decrease in late phase of sepsis (18?h after CLP) Mean arterial blood pressure and left ventricular dp/dt max remained relatively unaltered during early phase of sepsis but was decreased during late phase of sepsis Although septic rat heart exhibited biphasic cardiodynamic changes, myocardial function showed signs of progressive deterioration during the development of sepsis, as indicated by a progressive elevation of LVEDP [ 125 I] ET1 bindings to cardiac membranes exhibited a saturable process with a single component binding characteristic for all three experimental groups In sarcolemmal membrane fraction, the maximum binding capacity (B max ) calculated from scatchard plot was increased 30% ( P <0 01) during early phase of sepsis but decreased 24% ( P <0 01) during late phase of sepsis The affinity [the reciprocal of the dissociation contant (Kd)] for [ 125 I] ET1 binding in sarcolemmal membranes remained unaffected during early and late phases of sepsis In light vesicle fraction, the B max for [ 125 I] ET1 binding was decreased by 19% ( P <0 05) during early phase of sepsis but increased by 38% ( P <0 01) during late phase of sepsis The affinity for [ 125 I] ET1 binding in light vesicles was unaltered in early and late phases of sepsis It should be mentioned that the sum of Bmax of sarcolemmal and light vesicle fractions was increased by 25% ( P <0 01) during early phase of sepsis but was decreased by 17% ( P <0 01) during late phase of sepsis Conclusions These data indicated that a biphasic intracellular redistribution of ET1 receptor in the heart might contribute to the development of the initial hyperdynamic and subsequent hypodynamic state during sepsis展开更多
基金Key project from the Natural Science Foundation of China (59836250)
文摘Internal and external wall surface temperatures (Tws) in April, August and December in Kunming, a city in low latitude plateau, were investigated. Results showed that the Tws in April were of the highest among the three, followed by August and December. The Tws differences among walls with different orientation were higher in April and December when the weather tends to be sunny, and lower in August with more cloudy days in the time. In April and August, Tws of E-wall was the highest, followed by S- and N-wall. But in December Tws of S-wall might be sometimes higher than E one. Diurnal range of internal Tws was usually smaller than that of the external, with also a time lag for the occurrence of its maximum and minimum. The results can serve as a basis for further research on building microclimate and urban architecture designs. It also gives suggestions for similar studies in other areas.
文摘The receiver is an important element in solar energy plants.The principal receiver’s tubes in power plants are devised to work under extremely severe conditions,including excessive heat fluxes.Half of the tube’s circumference is heated whilst the other half is insulated.This study aims to improve the heat transfer process and reinforce the tubes’structure by designing a new receiver;by including longitudinal fins of triangular,circular and square shapes.The research is conducted experimentally using Reynolds numbers ranging from 28,000 to 78,000.Triangular fins have demonstrated the best improvement for heat transfer.For Reynolds number value near 43,000 Nusselt number(Nu)is higher by 3.5%and 7.5%,sequentially,compared to circular and square tube fins,but varies up to 6.5%near Re=61000.The lowest friction factor is seen in a triangular fin receiver;where it deviates from circular fins by 4.6%,and square fin tubes by 3.2%.Adding fins makes the temperature decrease gradually,and in the case of no fins,the temperature gradient between the hot tube and water drops sharply in the planed tube by 7%.
文摘Objective To study the redistribution of ET1 receptors in two subcellular organelles, the sarcolemmal membrane and the light vesicle, of rat heart during the progress of septic shock Methods Male Sprague Dawley rats weighing from 270 to 320?g were randomly divided into three groups: control, early sepsis, and late sepsis Each group included six rats Sepsis was induced by cecal ligation and puncture (CLP) Control rats were sham operated After operation for 9 hours or 18 hours, animals of the three groups were anesthetized with sodium pentobarbital (60?mg/kg IP) and the hearts were removed for preparation of sarcolemma and light vesicle Hemodynamic parameters were determined with polygraph via femoral artery and intraventricular cannula ET1 receptor was assayed by [ 125 I] ET1 binding Results Heart rate, cardiac output and left ventricular +dp/dt max undergo biphasic changes: an increase in early phase of sepsis (9?h after CLP) followed by a decrease in late phase of sepsis (18?h after CLP) Mean arterial blood pressure and left ventricular dp/dt max remained relatively unaltered during early phase of sepsis but was decreased during late phase of sepsis Although septic rat heart exhibited biphasic cardiodynamic changes, myocardial function showed signs of progressive deterioration during the development of sepsis, as indicated by a progressive elevation of LVEDP [ 125 I] ET1 bindings to cardiac membranes exhibited a saturable process with a single component binding characteristic for all three experimental groups In sarcolemmal membrane fraction, the maximum binding capacity (B max ) calculated from scatchard plot was increased 30% ( P <0 01) during early phase of sepsis but decreased 24% ( P <0 01) during late phase of sepsis The affinity [the reciprocal of the dissociation contant (Kd)] for [ 125 I] ET1 binding in sarcolemmal membranes remained unaffected during early and late phases of sepsis In light vesicle fraction, the B max for [ 125 I] ET1 binding was decreased by 19% ( P <0 05) during early phase of sepsis but increased by 38% ( P <0 01) during late phase of sepsis The affinity for [ 125 I] ET1 binding in light vesicles was unaltered in early and late phases of sepsis It should be mentioned that the sum of Bmax of sarcolemmal and light vesicle fractions was increased by 25% ( P <0 01) during early phase of sepsis but was decreased by 17% ( P <0 01) during late phase of sepsis Conclusions These data indicated that a biphasic intracellular redistribution of ET1 receptor in the heart might contribute to the development of the initial hyperdynamic and subsequent hypodynamic state during sepsis
