Fatigue tests were conducted on tapered plain concrete prism specimens under tri axial constant-amplitude tension-compression cyclic loading. The low stress of the cyclic loading was taken as 0.2f c and the upper st...Fatigue tests were conducted on tapered plain concrete prism specimens under tri axial constant-amplitude tension-compression cyclic loading. The low stress of the cyclic loading was taken as 0.2f c and the upper stress ranged from 0. 20f t to 0.65f t. Three constant lateral pressures were 0.1f c, 0.2f c and 0.3f c respec tively. Based on the results, the th ree-stage evolution rule of the fatigue stiffness, maximum(minimum) longitudina l strain and damage were analyzed, and a unified S-N curve to calculate fati gue strength factors was worked out. The results show that the fatigue strength and fa tigue life under triaxial constant-amplitude tension-compression cyclic loadin g are smaller than those under uniaxial fatigue condition. Moreover, the secondary strain creep rate is related to the fatigue life, a formula for describing thei r relation was derived. The investigation of this paper can provide information for the fatigue design of concrete structures.展开更多
Dubrovin establishes a certain relationship between the GUE partition function and the partition function of Gromov-Witten invariants of the complex projective line.In this paper,we give a direct proof of Dubrovin’s ...Dubrovin establishes a certain relationship between the GUE partition function and the partition function of Gromov-Witten invariants of the complex projective line.In this paper,we give a direct proof of Dubrovin’s result.We also present in a diagram the recent progress on topological gravity and matrix gravity.展开更多
For an arbitrary solution to the Volterra lattice hierarchy,the logarithmic derivatives of the tau-function of the solution can be computed by the matrix-resolvent method.In this paper,we define a pair of wave functio...For an arbitrary solution to the Volterra lattice hierarchy,the logarithmic derivatives of the tau-function of the solution can be computed by the matrix-resolvent method.In this paper,we define a pair of wave functions of the solution and use them to give an expression of the matrix resolvent;based on this we obtain a new formula for the k-point functions for the Volterra lattice hierarchy in terms of wave functions.As an application,we give an explicit formula of k-point functions for the even GUE(Gaussian Unitary Ensemble)correlators.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.50078010)
文摘Fatigue tests were conducted on tapered plain concrete prism specimens under tri axial constant-amplitude tension-compression cyclic loading. The low stress of the cyclic loading was taken as 0.2f c and the upper stress ranged from 0. 20f t to 0.65f t. Three constant lateral pressures were 0.1f c, 0.2f c and 0.3f c respec tively. Based on the results, the th ree-stage evolution rule of the fatigue stiffness, maximum(minimum) longitudina l strain and damage were analyzed, and a unified S-N curve to calculate fati gue strength factors was worked out. The results show that the fatigue strength and fa tigue life under triaxial constant-amplitude tension-compression cyclic loadin g are smaller than those under uniaxial fatigue condition. Moreover, the secondary strain creep rate is related to the fatigue life, a formula for describing thei r relation was derived. The investigation of this paper can provide information for the fatigue design of concrete structures.
文摘Dubrovin establishes a certain relationship between the GUE partition function and the partition function of Gromov-Witten invariants of the complex projective line.In this paper,we give a direct proof of Dubrovin’s result.We also present in a diagram the recent progress on topological gravity and matrix gravity.
基金supported by the National Key R and D Program of China(2020YFA0713100).
文摘For an arbitrary solution to the Volterra lattice hierarchy,the logarithmic derivatives of the tau-function of the solution can be computed by the matrix-resolvent method.In this paper,we define a pair of wave functions of the solution and use them to give an expression of the matrix resolvent;based on this we obtain a new formula for the k-point functions for the Volterra lattice hierarchy in terms of wave functions.As an application,we give an explicit formula of k-point functions for the even GUE(Gaussian Unitary Ensemble)correlators.
文摘目的:探讨竹荪多糖对砷中毒大鼠肝损伤的影响。方法:将24只清洁级健康SD大鼠均分为对照组、模型组、竹荪干预组3组,每组雌雄各半;对照组以常规饲料饲养,竹荪干预组和模型组喂饲砷含量50 mg/kg的饲料,竹荪干预组每日以10 g/L的竹荪多糖20 m L/kg灌胃,各组大鼠喂养3个月时取血检测血清谷草转氨酶(AST)及谷丙转氨酶(ALT)活力、总蛋白(TP)及白蛋白(ALB)水平、白蛋白与球蛋白比值(A/G)、粘连蛋白(LN)、透明质酸酶(HA)、Ⅲ型前胶原(PCⅢ)以及Ⅳ型胶原(PCIV)的水平;取大鼠同一肝小叶行HE及Masson染色,观察肝组织病理学改变,并计算肝纤维化增生面积。结果:与对照组相比,竹荪干预组和模型组大鼠血清内AST的活力均升高,ALB水平降低,LN、HA、PCIV水平增高,差异有统计学意义(P<0.05);与模型组相比,竹荪干预组大鼠血清内AST和ALT的活力均降低,TP、A/G、ALB水平升高,LN、PCIV水平降低,差异有统计学意义(P<0.05);HE和Masson染色结果显示,竹荪干预组和模型组均出现不同程度的肝损伤;通过图像分析系统测量,对照组、竹荪干预组、模型组大鼠肝脏增生纤维面积呈增加趋势,竹荪干预组和模型组与对照组相比胶原纤维沉积面积差异均有统计学意义(P<0.05)。结论:竹荪多糖对砷中毒大鼠肝脏有一定的保护作用。
