The deployable mechanisms consisting of square units are widely applied in aeronautics and astronautics,biomedicine, architecture and other fields, and joint clearance in such a mechanism is unavoidable. This study is...The deployable mechanisms consisting of square units are widely applied in aeronautics and astronautics,biomedicine, architecture and other fields, and joint clearance in such a mechanism is unavoidable. This study is carried out to accurately investigate the dynamic property of the mechanism.Firstly,a dynamics model was built by considering the motion characteristics between elements of joint with clearances. Secondly,based on Floures contact force model and LuGre friction force model,the tangential and normal contact force of revolute pair element with clearance were calculated respectively. Finally,square combined mechanisms' dynamic analytical method considering joint clearance was investigated, and constraint renege problem was resolved by adopting Baumgarte stable constraint method in integration process.Analytical result indicates that the impact of joint clearance on dynamic property of square combined mechanism should not be neglected.展开更多
Let Q 2 = [0, 1]2 be the unit square in two dimension Euclidean space ?2. We study the L p boundedness properties of the oscillatory integral operators T α,β defined on the set S(?3) of Schwartz test functions f by ...Let Q 2 = [0, 1]2 be the unit square in two dimension Euclidean space ?2. We study the L p boundedness properties of the oscillatory integral operators T α,β defined on the set S(?3) of Schwartz test functions f by $$ \mathcal{T}_{\alpha ,\beta } f(x,y,z) = \int_{Q^2 } {f(x - t,y - s,z - t^k s^j )e^{ - it^{ - \beta _1 } s^{ - \beta 2} } t^{ - 1 - \alpha _1 } s^{ - 1 - \alpha _2 } dtds} , $$ where β1 > α1 ? 0, β2 > α2 ? 0 and (k, j) ∈ ?2. As applications, we obtain some L p boundedness results of rough singular integral operators on the product spaces.展开更多
Let T denote a finite set of points in a unit isoscele right triangle (i.e., the right sides are both one), f(T) the minimum distance between pairs of points of T, and In this paper, the exact values of f△ (n) for 2...Let T denote a finite set of points in a unit isoscele right triangle (i.e., the right sides are both one), f(T) the minimum distance between pairs of points of T, and In this paper, the exact values of f△ (n) for 2≤n≤7 and the corresponding configurations are given.展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No.51175422)
文摘The deployable mechanisms consisting of square units are widely applied in aeronautics and astronautics,biomedicine, architecture and other fields, and joint clearance in such a mechanism is unavoidable. This study is carried out to accurately investigate the dynamic property of the mechanism.Firstly,a dynamics model was built by considering the motion characteristics between elements of joint with clearances. Secondly,based on Floures contact force model and LuGre friction force model,the tangential and normal contact force of revolute pair element with clearance were calculated respectively. Finally,square combined mechanisms' dynamic analytical method considering joint clearance was investigated, and constraint renege problem was resolved by adopting Baumgarte stable constraint method in integration process.Analytical result indicates that the impact of joint clearance on dynamic property of square combined mechanism should not be neglected.
基金the National Natural Science Foundation of China (Grant Nos. 10571122, 10371046)the Natural Science Foundation of Fujian Province of China (Grant No. Z0511004)
文摘Let Q 2 = [0, 1]2 be the unit square in two dimension Euclidean space ?2. We study the L p boundedness properties of the oscillatory integral operators T α,β defined on the set S(?3) of Schwartz test functions f by $$ \mathcal{T}_{\alpha ,\beta } f(x,y,z) = \int_{Q^2 } {f(x - t,y - s,z - t^k s^j )e^{ - it^{ - \beta _1 } s^{ - \beta 2} } t^{ - 1 - \alpha _1 } s^{ - 1 - \alpha _2 } dtds} , $$ where β1 > α1 ? 0, β2 > α2 ? 0 and (k, j) ∈ ?2. As applications, we obtain some L p boundedness results of rough singular integral operators on the product spaces.
文摘Let T denote a finite set of points in a unit isoscele right triangle (i.e., the right sides are both one), f(T) the minimum distance between pairs of points of T, and In this paper, the exact values of f△ (n) for 2≤n≤7 and the corresponding configurations are given.
