The initiation mechanism of debris flow is regarded as the key step in understanding the debrisflow processes of occurrence, development and damage. Moreover, migration, accumulation and blocking effects of fine parti...The initiation mechanism of debris flow is regarded as the key step in understanding the debrisflow processes of occurrence, development and damage. Moreover, migration, accumulation and blocking effects of fine particles in soil will lead to soil failure and then develop into debris flow. Based on this hypothesis and considering the three factors of slope gradient, rainfall duration and rainfall intensity, 16 flume experiments were designed using the method of orthogonal design and completed in a laboratory. Particle composition changes in slope toe, volumetric water content, fine particle movement characteristics and soil failure mechanism were analyzed and understood as follows: the soil has complex, random and unstable structures, which causes remarkable pore characteristics of poor connectivity, non-uniformity and easy variation. The major factors that influence fine particle migration are rainfall intensity and slope. Rainfall intensity dominates particle movement, whereby high intensity rainfall induces a large number of mass movement and sharp fluctuation, causing more fine particles to accumulate at the steep slope toe. The slope toe plays an important role in water collection and fine particleaccumulation. Both fine particle migration and coarse particle movement appears similar fluctuation. Fine particle migration is interrupted in unconnected pores, causing pore blockage and fine particle accumulation, which then leads to the formation of a weak layer and further soil failure or collapses. Fine particle movement also causes debris flow formation in two ways: movement on the soil surface and migration inside the soil. The results verify the hypothesis that the function of fine particle migration in soil failure process is conducive for further understanding the formation mechanism of soil failure and debris flow initiation.展开更多
AIM: To evaluate the correlation of shear wave elastography (SWE) results with liver fibrosis histology and quantitative function reserve. METHODS: Weekly subcutaneous injection of 60% carbon tetrachloride (1.5 mL/kg)...AIM: To evaluate the correlation of shear wave elastography (SWE) results with liver fibrosis histology and quantitative function reserve. METHODS: Weekly subcutaneous injection of 60% carbon tetrachloride (1.5 mL/kg) was given to 12 canines for 24 wk to induce experimental liver fibrosis, with olive oil given to 2 control canines. At 24 wk, liver condition was evaluated using clinical biochemistry assays, SWE imaging, lidocaine metabolite monoethylglycine-xylidide (MEGX) test, and histologic fibrosis grading. Clinical biochemistry assays were performed at the institutional central laboratory for routine liver function evaluation. Liver stiffness was measured in triplicate from three different intercostal spaces and expressed as mean liver stiffness modulus (LSM). Plasma concentrations of lidocaine and its metabolite MEGX were determined using high-performance liquid chromatography repeated in duplicate. Liver biopsy samples were fixed in 10% formaldehyde, and liver fibrosis was graded using the modified histological activity index Knodell score (F0-F4). Correlations among histologic grading, LSM, and MEGX measures were analyzed with the Pearson linear correlation coefficient. RESULTS: At 24 wk liver fibrosis histologic grading was as follows: F0, n = 2 (control); F1, n = 0; F2, n = 3; F3, n = 7; and F4, n = 2. SWE LSM was positively correlated with histologic grading (r = 0.835, P < 0.001). Specifically, the F4 group had a significantly higher elastic modulus than the F3, F2, and F0 groups (P = 0.002, P = 0.003, and P = 0.006, respectively), and the F3 group also had a significantly higher modulus than the control F0 group (P = 0.039). LSM was negatively associated with plasma MEGX concentrations at 30 min (r = -0.642; P = 0.013) and 60 min (r = -0.651; P = 0.012), time to 1/2 of the maximum concentration (r = -0.538; P = 0.047), and the area under the curve (r = -0.636; P = 0.014). Multiple comparisons showed identical differences in these three measures: significantly lower with F4 (P = 0.037) and F3 (P = 0.03展开更多
为减少因热拌沥青混合料产生的热量和烟雾对施工人员身体健康的危害,开发了一种拌和温度低、阻燃效果好、降噪效果好的温拌阻燃降噪型沥青混合料。通过室内试验,分析了沥青的阻燃效果,对阻燃温拌降噪型沥青混合料OGFC-13与热拌沥青混合...为减少因热拌沥青混合料产生的热量和烟雾对施工人员身体健康的危害,开发了一种拌和温度低、阻燃效果好、降噪效果好的温拌阻燃降噪型沥青混合料。通过室内试验,分析了沥青的阻燃效果,对阻燃温拌降噪型沥青混合料OGFC-13与热拌沥青混合料AC-13在不同拌和温度下阻燃方面、降噪效果方面的优越性进行了试验研究,并通过江西省赤水隧道项目试验路的铺筑验证温拌阻燃降噪型沥青混合料在施工中优良的铺筑效果。结果表明,采用添加温拌剂和阻燃剂的温拌阻燃技术,能够使得温拌阻燃降噪型沥青混合料在没有影响路用性能的基础上,较普通热拌沥青混合料具良好的降温、阻燃和降噪性能,在试验路的铺筑过程中该种混合料没有产生大量的热量和烟雾,通过试验路铺筑后的噪音测试,该种混合料可以降低5 d B左右的噪音。展开更多
基金supported by the key international collaborative project of Natural Science Foundation of China(No.41520104002)
文摘The initiation mechanism of debris flow is regarded as the key step in understanding the debrisflow processes of occurrence, development and damage. Moreover, migration, accumulation and blocking effects of fine particles in soil will lead to soil failure and then develop into debris flow. Based on this hypothesis and considering the three factors of slope gradient, rainfall duration and rainfall intensity, 16 flume experiments were designed using the method of orthogonal design and completed in a laboratory. Particle composition changes in slope toe, volumetric water content, fine particle movement characteristics and soil failure mechanism were analyzed and understood as follows: the soil has complex, random and unstable structures, which causes remarkable pore characteristics of poor connectivity, non-uniformity and easy variation. The major factors that influence fine particle migration are rainfall intensity and slope. Rainfall intensity dominates particle movement, whereby high intensity rainfall induces a large number of mass movement and sharp fluctuation, causing more fine particles to accumulate at the steep slope toe. The slope toe plays an important role in water collection and fine particleaccumulation. Both fine particle migration and coarse particle movement appears similar fluctuation. Fine particle migration is interrupted in unconnected pores, causing pore blockage and fine particle accumulation, which then leads to the formation of a weak layer and further soil failure or collapses. Fine particle movement also causes debris flow formation in two ways: movement on the soil surface and migration inside the soil. The results verify the hypothesis that the function of fine particle migration in soil failure process is conducive for further understanding the formation mechanism of soil failure and debris flow initiation.
基金Supported by National Natural Science Foundation of ChinaNo.81401425
文摘AIM: To evaluate the correlation of shear wave elastography (SWE) results with liver fibrosis histology and quantitative function reserve. METHODS: Weekly subcutaneous injection of 60% carbon tetrachloride (1.5 mL/kg) was given to 12 canines for 24 wk to induce experimental liver fibrosis, with olive oil given to 2 control canines. At 24 wk, liver condition was evaluated using clinical biochemistry assays, SWE imaging, lidocaine metabolite monoethylglycine-xylidide (MEGX) test, and histologic fibrosis grading. Clinical biochemistry assays were performed at the institutional central laboratory for routine liver function evaluation. Liver stiffness was measured in triplicate from three different intercostal spaces and expressed as mean liver stiffness modulus (LSM). Plasma concentrations of lidocaine and its metabolite MEGX were determined using high-performance liquid chromatography repeated in duplicate. Liver biopsy samples were fixed in 10% formaldehyde, and liver fibrosis was graded using the modified histological activity index Knodell score (F0-F4). Correlations among histologic grading, LSM, and MEGX measures were analyzed with the Pearson linear correlation coefficient. RESULTS: At 24 wk liver fibrosis histologic grading was as follows: F0, n = 2 (control); F1, n = 0; F2, n = 3; F3, n = 7; and F4, n = 2. SWE LSM was positively correlated with histologic grading (r = 0.835, P < 0.001). Specifically, the F4 group had a significantly higher elastic modulus than the F3, F2, and F0 groups (P = 0.002, P = 0.003, and P = 0.006, respectively), and the F3 group also had a significantly higher modulus than the control F0 group (P = 0.039). LSM was negatively associated with plasma MEGX concentrations at 30 min (r = -0.642; P = 0.013) and 60 min (r = -0.651; P = 0.012), time to 1/2 of the maximum concentration (r = -0.538; P = 0.047), and the area under the curve (r = -0.636; P = 0.014). Multiple comparisons showed identical differences in these three measures: significantly lower with F4 (P = 0.037) and F3 (P = 0.03
文摘为减少因热拌沥青混合料产生的热量和烟雾对施工人员身体健康的危害,开发了一种拌和温度低、阻燃效果好、降噪效果好的温拌阻燃降噪型沥青混合料。通过室内试验,分析了沥青的阻燃效果,对阻燃温拌降噪型沥青混合料OGFC-13与热拌沥青混合料AC-13在不同拌和温度下阻燃方面、降噪效果方面的优越性进行了试验研究,并通过江西省赤水隧道项目试验路的铺筑验证温拌阻燃降噪型沥青混合料在施工中优良的铺筑效果。结果表明,采用添加温拌剂和阻燃剂的温拌阻燃技术,能够使得温拌阻燃降噪型沥青混合料在没有影响路用性能的基础上,较普通热拌沥青混合料具良好的降温、阻燃和降噪性能,在试验路的铺筑过程中该种混合料没有产生大量的热量和烟雾,通过试验路铺筑后的噪音测试,该种混合料可以降低5 d B左右的噪音。
