The size of pores or the grille spacing of water–sediment separation structures directly affects their regulation effect on the debris flow performance.A suitable pore size or grille spacing can effectively improve t...The size of pores or the grille spacing of water–sediment separation structures directly affects their regulation effect on the debris flow performance.A suitable pore size or grille spacing can effectively improve the water–sediment separation ability of the structure.The new funnel-type grating water–sediment separation structure(FGWSS)combines vertical and horizontal structures and provides a satisfactory water–sediment separation effect.However,the regulation effect of the grille spacing of the structure on the debris flow performance has not been studied.The regulation effect of the structure grille spacing on the debris flow performance is studied through a flume test,and the optimal structure grille spacing is obtained.An empirical equation of the relationship between the relative grille spacing of the structure and the sediment separation rate is established.Finally,the influence of the water–sediment separation structure on the regulation effect of debris flows is examined from two aspects:external factors(properties of debris flows)and internal factors(structural factors).The experimental results show that the gradation characteristics of solid particles in debris flows constitute a key factor affecting the regulation effect of the structure on the debris flow performance.The optimum grille spacing of the FGWSS matches the particle size corresponding to the material distribution curves d85~d90 of the debris flow.The total separation rate of debris flow particles is related to the grille spacing of the structure and the content of coarse and fine particles in the debris flow.展开更多
The friction coefficients between the surfaces of a ball and a disc lubricated by a space lubricating oil No.4129 were measured at various operating conditions on a ball-disc friction test rig. Friction characteristic...The friction coefficients between the surfaces of a ball and a disc lubricated by a space lubricating oil No.4129 were measured at various operating conditions on a ball-disc friction test rig. Friction characteristic curves were obtained under sliding and rolling movements at point contact. A new model for calculation of the friction coefficient was presented. The results show that the bigger the load is, the larger the friction coefficient becomes. The rolling speed ranging from 1 m/s to10 m/s has an important effect on the friction coefficient. The friction coefficient increases with the increase in sliding speed and the decrease in rolling speed. The linear variation region of the friction coefficient versus the sliding speed at high rolling speed is wider than that at low rolling speed. The model for calculation of the friction coefficient is accurate for engineering use.展开更多
文摘目的:探究肝硬化相关血清学指标与肝硬化Child-Pugh分级之间的关系和临床意义。方法:收集重庆医科大学附属第二医院感染科2016年7月至2017年4月间肝硬化患者血清235例,其中Child-Pugh A组55例,B组90例,C组90例,以及同期健康体检人群35例,分别检测肝功能、肝纤维化、血小板计数等指标并分析其特征。结果:透明质酸(hyaluronic acid,HA)、层粘连蛋白(laminin,LN)、Ⅲ型胶原蛋白(typeⅢcollagen,PC-Ⅲ)、Ⅳ型胶原蛋白(typeⅣcollagen,Ⅳ-C)、天门冬氨酸氨基转移酶(aspartate aminotransferase,AST)、丙氨酰氨基转移酶(alanyl aminotransferase,ALT)及天门冬氨酸氨基转移酶与血小板计数比(aspartate aminotransferase to platelet ratio index,APRI)指数之间差异均具有统计学意义(P<0.05)。HA、PC-Ⅲ、Ⅳ-C、LN和AST指标对预测肝硬化的曲线下面积(AUC)分别为0.910、0.804、0.833、0.753、0.730。HA、PC-Ⅲ、Ⅳ-C与Child-Pugh分级呈高度正相关(r>0.7,P<0.01),APRI与分级呈显著性正相关(0.4<r<0.7,P<0.05)。结论:HA、PC-Ⅲ、Ⅳ-C、APRI可作为Child-Pugh分级的潜在临床指标,这将有助于临床更好地制定诊疗方案及预后评估。
基金supported by the National Natural Science Foundation of China(Grant Nos.42027806 and 42041006)。
文摘The size of pores or the grille spacing of water–sediment separation structures directly affects their regulation effect on the debris flow performance.A suitable pore size or grille spacing can effectively improve the water–sediment separation ability of the structure.The new funnel-type grating water–sediment separation structure(FGWSS)combines vertical and horizontal structures and provides a satisfactory water–sediment separation effect.However,the regulation effect of the grille spacing of the structure on the debris flow performance has not been studied.The regulation effect of the structure grille spacing on the debris flow performance is studied through a flume test,and the optimal structure grille spacing is obtained.An empirical equation of the relationship between the relative grille spacing of the structure and the sediment separation rate is established.Finally,the influence of the water–sediment separation structure on the regulation effect of debris flows is examined from two aspects:external factors(properties of debris flows)and internal factors(structural factors).The experimental results show that the gradation characteristics of solid particles in debris flows constitute a key factor affecting the regulation effect of the structure on the debris flow performance.The optimum grille spacing of the FGWSS matches the particle size corresponding to the material distribution curves d85~d90 of the debris flow.The total separation rate of debris flow particles is related to the grille spacing of the structure and the content of coarse and fine particles in the debris flow.
基金supported by the National Science Foundation of China (51105131)the Excellent Youth Foundation of Henan Scientific Committee (12410050002)the Creative Talent Foundation at Universities of Henan Province (2011HASTIT1016)
文摘The friction coefficients between the surfaces of a ball and a disc lubricated by a space lubricating oil No.4129 were measured at various operating conditions on a ball-disc friction test rig. Friction characteristic curves were obtained under sliding and rolling movements at point contact. A new model for calculation of the friction coefficient was presented. The results show that the bigger the load is, the larger the friction coefficient becomes. The rolling speed ranging from 1 m/s to10 m/s has an important effect on the friction coefficient. The friction coefficient increases with the increase in sliding speed and the decrease in rolling speed. The linear variation region of the friction coefficient versus the sliding speed at high rolling speed is wider than that at low rolling speed. The model for calculation of the friction coefficient is accurate for engineering use.
