通过对湿重度分别为5.5 k N/m^(3)、6 k N/m^(3)的泡沫轻质土进行渗透及吸失水试验,研究了泡沫轻质土的孔隙状态、渗透系数及吸失水性能。试验结果表明:气泡混合轻质土是一种高孔隙率材料,其孔隙占比在75%以上,渗透系数约为10^(-5)~10^(...通过对湿重度分别为5.5 k N/m^(3)、6 k N/m^(3)的泡沫轻质土进行渗透及吸失水试验,研究了泡沫轻质土的孔隙状态、渗透系数及吸失水性能。试验结果表明:气泡混合轻质土是一种高孔隙率材料,其孔隙占比在75%以上,渗透系数约为10^(-5)~10^(-6)数量级,介于粉质粘土与粘土的渗透系数之间;受水浸泡后,泡沫轻质土容重最大增加约25%,失水后容重仍然有约9.5%增加量,在工程设计中应根据不同置换路基施工环境对设计容重按照1.0~1.25之间进行修正。展开更多
Body mass, volume and surface area are important for many aspects of the physiology and performance of species. Whereas body mass scaling received a lot of attention in the literature, surface areas of animals have no...Body mass, volume and surface area are important for many aspects of the physiology and performance of species. Whereas body mass scaling received a lot of attention in the literature, surface areas of animals have not been measured explicitly in this context. We quantified surface area-volume （SA/V） ratios for the first time using 3D surface models based on a structured light scanning method for 126 species of pollinating insects from 4 orders （Diptera, Hymenoptera, Lepidoptera, and Coleoptera）. Water loss of 67 species was measured gravimetrically at very dry conditions for 2 h at 15 and 30 ℃ to demonstrate the applicability of the new 3D surface measurements and relevance for predicting the performance of insects. Quantified SA/V ratios significantly explained the variation in water loss across species, both directly or after accounting for isometric scaling （residuals of the SA/V - mass2/3 relationship）. Small insects with a proportionally larger surface area had the highest water loss rates. Surface scans of insects to quantify allometric SA/Vratios thus provide a promising method to predict physiological responses, improving the potential of body mass isometry alone that assume geometric similarity.展开更多
LED lighting has problems such as short life span, power reduction due to the LED chip's heat, and decreased luminance efficiency etc. Many studies on the optimization of the thermal performance of LEDs have been ...LED lighting has problems such as short life span, power reduction due to the LED chip's heat, and decreased luminance efficiency etc. Many studies on the optimization of the thermal performance of LEDs have been conducted actively to solve these problems. The present study changes the fin shape and intervals of various heat sink designs so that LED can effectively produce a thermal effect. The water-cooling heat release system and the heat pipe methods show higher thermal performance results than the existing systems; however, the system is of high cost and requires a large-scale apparatus. This study carried out a numerical analysis of the thermal control system by applying heat flux and heat sink properties as an active heat release system using the commercial code ANSYS ver. 13.0 and verified the validity of the new heat sink design for temperature distribution analysis.展开更多
文摘通过对湿重度分别为5.5 k N/m^(3)、6 k N/m^(3)的泡沫轻质土进行渗透及吸失水试验,研究了泡沫轻质土的孔隙状态、渗透系数及吸失水性能。试验结果表明:气泡混合轻质土是一种高孔隙率材料,其孔隙占比在75%以上,渗透系数约为10^(-5)~10^(-6)数量级,介于粉质粘土与粘土的渗透系数之间;受水浸泡后,泡沫轻质土容重最大增加约25%,失水后容重仍然有约9.5%增加量,在工程设计中应根据不同置换路基施工环境对设计容重按照1.0~1.25之间进行修正。
文摘Body mass, volume and surface area are important for many aspects of the physiology and performance of species. Whereas body mass scaling received a lot of attention in the literature, surface areas of animals have not been measured explicitly in this context. We quantified surface area-volume （SA/V） ratios for the first time using 3D surface models based on a structured light scanning method for 126 species of pollinating insects from 4 orders （Diptera, Hymenoptera, Lepidoptera, and Coleoptera）. Water loss of 67 species was measured gravimetrically at very dry conditions for 2 h at 15 and 30 ℃ to demonstrate the applicability of the new 3D surface measurements and relevance for predicting the performance of insects. Quantified SA/V ratios significantly explained the variation in water loss across species, both directly or after accounting for isometric scaling （residuals of the SA/V - mass2/3 relationship）. Small insects with a proportionally larger surface area had the highest water loss rates. Surface scans of insects to quantify allometric SA/Vratios thus provide a promising method to predict physiological responses, improving the potential of body mass isometry alone that assume geometric similarity.
基金Financial aid from the Korea Ministry of Education through the Brain Korea 21 Project [HRD Center for Convergence Mechanical System Design] is gratefully acknowledgedthe financial support of Sungkyunkwan University for his sabbatical year
文摘LED lighting has problems such as short life span, power reduction due to the LED chip's heat, and decreased luminance efficiency etc. Many studies on the optimization of the thermal performance of LEDs have been conducted actively to solve these problems. The present study changes the fin shape and intervals of various heat sink designs so that LED can effectively produce a thermal effect. The water-cooling heat release system and the heat pipe methods show higher thermal performance results than the existing systems; however, the system is of high cost and requires a large-scale apparatus. This study carried out a numerical analysis of the thermal control system by applying heat flux and heat sink properties as an active heat release system using the commercial code ANSYS ver. 13.0 and verified the validity of the new heat sink design for temperature distribution analysis.
