U型块石路基结构对多年冻土的降温作用   总被引：8，自引：6，他引：2  

吴青柏  崔巍  刘永智 《冰川冻土》2010,32(3)

通过对比北麓河试验段U型块石路基结构和普通路基下部土体温度监测研究,U型块石路基显著地抬升路基下部多年冻土上限,具有较强的降低多年冻土温度的作用.2005—2007年间,U型块石路基下多年冻土上限平均抬升幅度达0.9~1.4 m.路基中心下部0.5 m深土体温度降温幅度达1.13℃,原天然上限附近土体温度降温达1.28℃,5 m深的多年冻土降温幅度达0.77℃,且U型块石路基下部土体温度呈现逐年降低的趋势.然而,普通路基下部土体温度远比U型块石路基下部要高,2005年普通路基下部0.5 m深土体年平均温度比U型块石路基高1~3℃,1.5 m处高0.8~1.9℃,5 m处高1.2~1.5℃.同时,U型块石路基下部多年冻土上限抬升比普通路基大,2004—2006年间U型块石路基左路肩下多年冻土上限抬升比普通路基大0.86 m,路基中心大0.5 m.  相似文献   

Forskolin处理真鲷胚胎条件的研究          下载免费PDF全文

谭训刚  杜少军  张培军 《海洋科学》2005,29(4):5-7

研究Forskolin处理真鲷胚胎的条件。对加药时期以及Forskolin浓度进行了优化，得到了处理真鲷胚胎的加药时期为受精后6h，Forskolin的浓度为0．01nmol／L和0．02mol／L，在此条件下处理过的胚胎体节由正常的V型变成U型。该研究结果将有利于研究Hh信号对真鲷成肌因子的影响。  相似文献   

Performance of solid and perforated U-type breakwaters under regular and irregular waves   总被引：1，自引：0，他引：1  

K. Günayd&#x;n  M. S. Kabda l&#x; 《Ocean Engineering》2004,31(11-12):1377-1405

An experimental investigation of U-type breakwaters was carried out in a laboratory channel. Both regular and irregular waves were used during testing. Two types of breakwaters such as solid and perforated were studied to analyse the porosity effect of structures. In order to investigate performance of these breakwaters for different immersion depths, four depths of immersions of the solid and perforated breakwaters were selected. Different wave groups were generated over these breakwaters, and the transmission, reflection and energy dissipation characteristics of each breakwater were determined. Three coefficients such as transmission, reflection and energy dissipation coefficients, which were named as C_t, C_r, and C_l, respectively, were used during the evaluation of the test results. The most important parameters governing performance of these breakwaters were determined by using earlier investigations and experimental results. These parameters were expressed as a dimensionless group by using π theory. Based on the test results, empirical expressions were formulated to describe the C_t, C_r, and C_l for different immersion depths of solid and perforated breakwaters under regular and irregular waves.  相似文献   

Investigation of Π-type breakwaters performance under regular and irregular waves     

K. Günayd&#x;n  M.S. Kabdal&#x; 《Ocean Engineering》2007,34(7):1028-1043

In this paper, performance of solid and perforated Π-type breakwaters was investigated experimentally. Both regular and irregular waves were used during testing. Four depths of immersions were selected for each breakwater and wave type. Different wave groups were generated over these breakwaters, and the transmission, reflection and energy-dissipation characteristics were determined. The results of the experimental study were evaluated and some empirical expressions based on the results were suggested to define the transmission, reflection and energy-dissipation coefficients for different immersion depths of solid and perforated breakwaters under regular and irregular waves. Moreover, performance of solid and perforated Π-type breakwaters were compared with that of solid and perforated U-type breakwaters investigated by Günaydın and Kabdaşlı [2006. Performance of solid and perforated U-type breakwaters under regular and irregular waves. Ocean Engineering 31, 1377–1405]. These comparisons showed that the most reasonable model and wave type are selected to determine requiring performance parameters.  相似文献