Soil water repellency （SWR） is one of the most important physical properties of soils found all over the world, and it may have significant effects on the eco-hydrological processes of land ecosystems. In this study...Soil water repellency （SWR） is one of the most important physical properties of soils found all over the world, and it may have significant effects on the eco-hydrological processes of land ecosystems. In this study, the Capillary Rise Method was used to measure the SWR in the artificial vegetation area in Shapotou, located in the southeast area of the Tengger Desert, Ningxia Prov- ince of western China. The variation of the soil water repellency among different minor topographies, different depths and differ- ent particle sizes was analyzed. The results of the study indicate that the SWR shows distinct changes with vegetation restoration, and it increases with an increase in the period of dune stabilization. In the same vegetation area, the SWR of soils in inter-dune depressions or windward slopes is slightly greater than that in crest or leeward slopes. The SWR of 0-3 cm topsoil is significantly greater than that in the 3-6 cm soil layer. The SWR decreases with an increase in grain size and the differences among the SWRs of different sieved soil fractions are found to be significant. There is also a significantly positive correlation between the SWR and the proportion of soils with grain sizes of 0-0.05, 0.05-0.01 and 0.01-0.15 mm, and a significantly negative correlation between the SWR and the propotion of soils with grain sizes exceeding 0.15 mm. The increase of SWR in revegetation areas may depend on the continuous depositing of atmospheric dust on the stabilized dune surface as well as the formation of biological soil crusts, especially on the formation of algal and lichen crusts. Enhanced SWR influences the effectiveness of water use of sand plants in- habiting the sand dunes.展开更多
Since natural restoration combined with artificial auxiliary measures may achieve a relatively rapid restoration effect at a lower cost, it has become an essential measure for the ecological restoration of rock slopes...Since natural restoration combined with artificial auxiliary measures may achieve a relatively rapid restoration effect at a lower cost, it has become an essential measure for the ecological restoration of rock slopes. Previous studies have focused heavily on the relationship between substrate nutrients and water conditions and the development of mosses on the rock surface, but quantitative characterization of substantial effect of rock surface texture(e.g., microrelief) on moss growth is absent. The undulating microrelief on the rock surface can increase the heterogeneity of the microhabitat, which may be an important factor affecting the development of mossdominated biocrusts. In this study, the roughness of rock surfaces, moss coverage and biomass, weight and major nutrient contents of soils within the biocrusts were measured in the western mountainous area of Sichuan Province, Southwest China to further examine the role of rock surface microrelief in the biocrusts. The results showed that three main factors affecting the development of the biocrusts were bryophyte emergence, soil accumulation, and lithology. The presence of moss accelerates soil formation on rock surfaces and lead to the accumulation of nutrients so that all parts of the moss-dominated biocrusts system can develop synergistically. It was found that a microrelief structure with a roughness between 1.5 and 2.5 could gather soil and bryophyte propagules effectively, which may have a strong relationship with the angle of repose. When the roughness is 1.5, the corresponding undulation angle is very close to the theoretical minimum value of the undulation angle calculated according to the relationships between the undulation angle of the protrusion, slope and angle of repose.展开更多
目的:探讨微创全瓷贴面配合数字化微笑设计(Digital smile design,DSD)技术修复前牙切缘切角缺损的美学效果。方法:选取2019年1月-2022年1月笔者医院接诊的78例前牙切缘切角缺损患者为研究对象,采用区组随机化法分为观察组(116颗患牙)...目的:探讨微创全瓷贴面配合数字化微笑设计(Digital smile design,DSD)技术修复前牙切缘切角缺损的美学效果。方法:选取2019年1月-2022年1月笔者医院接诊的78例前牙切缘切角缺损患者为研究对象,采用区组随机化法分为观察组(116颗患牙)和对照组(120颗患牙),每组39例。对照组采用微创全瓷贴面修复,观察组给予微创全瓷贴面联合DSD技术进行修复。比较两组患者治疗6个月后的满意度、美学效果[美国公共卫生署评估标准(United states public health service,USPHS)],对比治疗前后两组患者的红色美学指数、牙周健康指数[牙龈指数(Gingival index,GI)、牙菌斑指数(Plaque index,PLI)、龈沟出血指数(Sulcus bleeding index,SBI)]的变化。结果:治疗6个月后,两组美学效果各维度评级有显著差异,观察组治疗满意率、红色美学指数评分均显著高于对照组(P<0.05);治疗6个月后,两组GI、PLI、SBI均明显降低,且观察组显著低于对照组(P<0.05)。结论:微创全瓷贴面联合DSD技术修复前牙切缘切角缺损可有效改善牙齿美学效果,提高患者治疗满意度,适合临床推广。展开更多
基金supported by the National Basic Research Program of China(Grant No.2009CB421303)the National Natural Sciences Foundation(Grant Nos.40971031,40701002)
文摘Soil water repellency （SWR） is one of the most important physical properties of soils found all over the world, and it may have significant effects on the eco-hydrological processes of land ecosystems. In this study, the Capillary Rise Method was used to measure the SWR in the artificial vegetation area in Shapotou, located in the southeast area of the Tengger Desert, Ningxia Prov- ince of western China. The variation of the soil water repellency among different minor topographies, different depths and differ- ent particle sizes was analyzed. The results of the study indicate that the SWR shows distinct changes with vegetation restoration, and it increases with an increase in the period of dune stabilization. In the same vegetation area, the SWR of soils in inter-dune depressions or windward slopes is slightly greater than that in crest or leeward slopes. The SWR of 0-3 cm topsoil is significantly greater than that in the 3-6 cm soil layer. The SWR decreases with an increase in grain size and the differences among the SWRs of different sieved soil fractions are found to be significant. There is also a significantly positive correlation between the SWR and the proportion of soils with grain sizes of 0-0.05, 0.05-0.01 and 0.01-0.15 mm, and a significantly negative correlation between the SWR and the propotion of soils with grain sizes exceeding 0.15 mm. The increase of SWR in revegetation areas may depend on the continuous depositing of atmospheric dust on the stabilized dune surface as well as the formation of biological soil crusts, especially on the formation of algal and lichen crusts. Enhanced SWR influences the effectiveness of water use of sand plants in- habiting the sand dunes.
基金supported by the Project of Assessment on Post-quake Ecosystem and Environment Recovery in Jiuzhaigou under Grant 5132202020000046the National Key Research and Development Programme of China under Grant 2017YFC0504902。
文摘Since natural restoration combined with artificial auxiliary measures may achieve a relatively rapid restoration effect at a lower cost, it has become an essential measure for the ecological restoration of rock slopes. Previous studies have focused heavily on the relationship between substrate nutrients and water conditions and the development of mosses on the rock surface, but quantitative characterization of substantial effect of rock surface texture(e.g., microrelief) on moss growth is absent. The undulating microrelief on the rock surface can increase the heterogeneity of the microhabitat, which may be an important factor affecting the development of mossdominated biocrusts. In this study, the roughness of rock surfaces, moss coverage and biomass, weight and major nutrient contents of soils within the biocrusts were measured in the western mountainous area of Sichuan Province, Southwest China to further examine the role of rock surface microrelief in the biocrusts. The results showed that three main factors affecting the development of the biocrusts were bryophyte emergence, soil accumulation, and lithology. The presence of moss accelerates soil formation on rock surfaces and lead to the accumulation of nutrients so that all parts of the moss-dominated biocrusts system can develop synergistically. It was found that a microrelief structure with a roughness between 1.5 and 2.5 could gather soil and bryophyte propagules effectively, which may have a strong relationship with the angle of repose. When the roughness is 1.5, the corresponding undulation angle is very close to the theoretical minimum value of the undulation angle calculated according to the relationships between the undulation angle of the protrusion, slope and angle of repose.
文摘目的:探讨微创全瓷贴面配合数字化微笑设计(Digital smile design,DSD)技术修复前牙切缘切角缺损的美学效果。方法:选取2019年1月-2022年1月笔者医院接诊的78例前牙切缘切角缺损患者为研究对象,采用区组随机化法分为观察组(116颗患牙)和对照组(120颗患牙),每组39例。对照组采用微创全瓷贴面修复,观察组给予微创全瓷贴面联合DSD技术进行修复。比较两组患者治疗6个月后的满意度、美学效果[美国公共卫生署评估标准(United states public health service,USPHS)],对比治疗前后两组患者的红色美学指数、牙周健康指数[牙龈指数(Gingival index,GI)、牙菌斑指数(Plaque index,PLI)、龈沟出血指数(Sulcus bleeding index,SBI)]的变化。结果:治疗6个月后,两组美学效果各维度评级有显著差异,观察组治疗满意率、红色美学指数评分均显著高于对照组(P<0.05);治疗6个月后,两组GI、PLI、SBI均明显降低,且观察组显著低于对照组(P<0.05)。结论:微创全瓷贴面联合DSD技术修复前牙切缘切角缺损可有效改善牙齿美学效果,提高患者治疗满意度,适合临床推广。
