Cloud vertical structures and precipitation over the Tibetan Plateau （TP） are analyzed and compared with its neighboring land and tropical oceans based on CloudSat/CALIPSO satellite measurements and TRMM precipitati...Cloud vertical structures and precipitation over the Tibetan Plateau （TP） are analyzed and compared with its neighboring land and tropical oceans based on CloudSat/CALIPSO satellite measurements and TRMM precipitation data. Results show that the TP generally has a compression effect on cloud systems, as manifested by a shrinking cloud depth and lowering cloud top. Precipitation is weaker over the TP than its neighboring regions and exhibits large seasonal variations. In summer, cloud ice particles over the TP are mostly located at lower altitude （5-10 km）, with a larger variability of sizes and aggregation （particle number concentration） under no-rain conditions compared to other regions. Ice water content becomes abundant and the number concentration tends to be dense at higher altitudes when precipitation is enhanced. However, even for heavy rainstorms, the aggregation is most likely between 100 and 250 L-1, whereas it can reach as high as 500 L-1 over its neighboring land and tropical oceans. Given the same magnitude of precipitation, the spectrum of ice particle sizes is found to be wider over the TP than other regions.展开更多
The microscopic morphology and pore structure characteristics of concrete with composite admixtures(fly ash and mineral powder) after chlorine salt erosion were analyzed via scanning electron microscopy(SEM) and mercu...The microscopic morphology and pore structure characteristics of concrete with composite admixtures(fly ash and mineral powder) after chlorine salt erosion were analyzed via scanning electron microscopy(SEM) and mercury injection porosimetry(MIP), providing the basis for the design and maintenance of concrete shafts in coal mines. The above-mentioned characteristics were compared with the macroscopic characteristic of concrete fractures under uniaxial compression. The results show that the macroscopic fracture characteristics of concrete under uniaxial compression change from longitudinal split fracture and oblique section shear fracture to conjugate cant fracture, and the degree of breakage increases.Interface cracks, cement paste cracks, spherical surface cracks, and aggregate cracks appear in concrete under uniaxial compression. In the early stages of corrosion, the original cracks which are obvious are repaired. When the corrosion becomes more serious, cement paste cracks appear, and the number of harmful holes increases while the number of harmless holes decreases. This study also reveals the relationship between the macroscopic properties and microscopic structure of concrete under chloride salt erosion. Finally, the paper preliminarily discussed the relationship between the macroscopic properties and mesoscopic characteristics of concrete under chlorine salt erosion.展开更多
基金jointly supported by the National Natural Science Foundation of China[grant number 91637312],[grant number 91437219]the Key Research Program of Frontier Sciences of CAS,the Third Tibetan Plateau Scientific Experiment[grant number GYHY201406001]+1 种基金the Science and Technology Development Project of Shanghai Meteorological Bureau[grant number QM201711]the Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund(second phase)
文摘Cloud vertical structures and precipitation over the Tibetan Plateau （TP） are analyzed and compared with its neighboring land and tropical oceans based on CloudSat/CALIPSO satellite measurements and TRMM precipitation data. Results show that the TP generally has a compression effect on cloud systems, as manifested by a shrinking cloud depth and lowering cloud top. Precipitation is weaker over the TP than its neighboring regions and exhibits large seasonal variations. In summer, cloud ice particles over the TP are mostly located at lower altitude （5-10 km）, with a larger variability of sizes and aggregation （particle number concentration） under no-rain conditions compared to other regions. Ice water content becomes abundant and the number concentration tends to be dense at higher altitudes when precipitation is enhanced. However, even for heavy rainstorms, the aggregation is most likely between 100 and 250 L-1, whereas it can reach as high as 500 L-1 over its neighboring land and tropical oceans. Given the same magnitude of precipitation, the spectrum of ice particle sizes is found to be wider over the TP than other regions.
基金The authors gratefully acknowledge the financial support for this work,provided by the Outstanding Youth Science Foundation of China(No.51322401)the Key Project of Chinese National Programs for Fundamental Research and Development of China(No.2015CB251601)+1 种基金the Science and Technology Project of the Chinese Ministry of Housing and Urban-Rural Construction of China(Nos.2013-K4-22 and 2014-K4-042)the General Program of Chinese National Building Materials Industry Technology Innovation Program of China(Nos.2014-M5-1 and 2014-M5-2)
文摘The microscopic morphology and pore structure characteristics of concrete with composite admixtures(fly ash and mineral powder) after chlorine salt erosion were analyzed via scanning electron microscopy(SEM) and mercury injection porosimetry(MIP), providing the basis for the design and maintenance of concrete shafts in coal mines. The above-mentioned characteristics were compared with the macroscopic characteristic of concrete fractures under uniaxial compression. The results show that the macroscopic fracture characteristics of concrete under uniaxial compression change from longitudinal split fracture and oblique section shear fracture to conjugate cant fracture, and the degree of breakage increases.Interface cracks, cement paste cracks, spherical surface cracks, and aggregate cracks appear in concrete under uniaxial compression. In the early stages of corrosion, the original cracks which are obvious are repaired. When the corrosion becomes more serious, cement paste cracks appear, and the number of harmful holes increases while the number of harmless holes decreases. This study also reveals the relationship between the macroscopic properties and microscopic structure of concrete under chloride salt erosion. Finally, the paper preliminarily discussed the relationship between the macroscopic properties and mesoscopic characteristics of concrete under chlorine salt erosion.
