产品尺寸和几何技术规范(Dimensional and Geometrical Product Specification and Verification,GPS)是有关产品几何特性的一系列技术标准,它贯穿于产品的研究、开发、设计、制造、验收到使用和维护的全过程。本文介绍了新一代GPS标准...产品尺寸和几何技术规范(Dimensional and Geometrical Product Specification and Verification,GPS)是有关产品几何特性的一系列技术标准,它贯穿于产品的研究、开发、设计、制造、验收到使用和维护的全过程。本文介绍了新一代GPS标准体系表面模型的概念及其数字化描述方法,探讨了基于新一代GPS的表面模型的操作技术。其中几何要素、特征、恒定类和恒定度等概念的引入。为实现几何技术规范的数字化描述、设计、评定与控制提供了必要的理论基础。有效地解决了产品更新换代在功能描述、规范设计和认证评定全过程中数学表达规范统一的难题。展开更多
For Riemann problem in n(n ≥ 3) dimensional(n-D) conservation laws, dimension of equations can be only reduced one dimension by applying self-similar approach, so transformed equations are at least two dimensional (2...For Riemann problem in n(n ≥ 3) dimensional(n-D) conservation laws, dimension of equations can be only reduced one dimension by applying self-similar approach, so transformed equations are at least two dimensional (2D) equations which are also very hard although some pioneer works have been done in references [1-3].展开更多
文摘产品尺寸和几何技术规范(Dimensional and Geometrical Product Specification and Verification,GPS)是有关产品几何特性的一系列技术标准,它贯穿于产品的研究、开发、设计、制造、验收到使用和维护的全过程。本文介绍了新一代GPS标准体系表面模型的概念及其数字化描述方法,探讨了基于新一代GPS的表面模型的操作技术。其中几何要素、特征、恒定类和恒定度等概念的引入。为实现几何技术规范的数字化描述、设计、评定与控制提供了必要的理论基础。有效地解决了产品更新换代在功能描述、规范设计和认证评定全过程中数学表达规范统一的难题。
基金Supported by the National Natural Science Foundation of China(No. 10001023), Huo Yingdong Fellowship(81004), Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry, Natural Science Foundation of Guangdong(No. 000804) and Natural Science Foundation of Guangdong Education Bureau(No. 200030).
文摘For Riemann problem in n(n ≥ 3) dimensional(n-D) conservation laws, dimension of equations can be only reduced one dimension by applying self-similar approach, so transformed equations are at least two dimensional (2D) equations which are also very hard although some pioneer works have been done in references [1-3].