科创中国

飞行过程中飞机姿态角速度变化会对摆扫式航空相机产生干扰,另外相机在拍摄时飞行方向上的景物与感光介质之间存在相对运动.为消除姿态角速度的干扰和前向像移,设计了一种基于F28335的机载相机两轴稳定平台系统.探讨了伺服控制系统的算法选择,介绍了硬件结构和软件流程.通过摇摆台试验证明,该两轴稳定平台动态精度高、运行可靠,满足相机拍摄时序和精度的要求.

Published studies in regard to coupler systems have been mainly focused on the manufacturing process or coupler strength issues. With the ever increasing of tonnage and length of heavy haul trains, lateral in-train forces generated by longitudinal in-train forces and coupler rotations have become a more and more significant safety issue for heavy haul train operations. Derailments caused by excessive lateral in-train forces are frequently reported. This article studies two typical coupler systems used on heavy haul locomotives. Their structures and stabilizing mechanism are analyzed before the corresponding models are developed. Coupler systems models are featured by two distinct stabilizing mechanism models and draft gear models with hysteresis considered. A model set which consists of four locomotives and three coupler systems is developed to study the rotational behavior of different coupler systems and their implications for locomotive dynamics. Simulated results indicate that when the locomotives are equipped with the type B coupler system, locomotives can meet the dynamics standard on tangent tracks; while the dynamics performance on curved tracks is very poor. The maximum longitudinal in-train force for locomotives equipped with the type B coupler system is 2000 kN. Simulations revealed a distinct trend for the type A coupler system. Locomotive dynamics are poorer for the type A case when locomotives are running on tangent tracks, while the dynamics are better for the type A case when locomotives are running on curved tracks. Theoretical studies and simulations carried out in this article suggest that a combination of the two types of stabilizing mechanism can result in a good design which can significantly decrease the relevant derailments.

根据物流跨行业、跨部门、综合性较强的特点,阐述了大型体育赛事物流信息平台的目标、定位、设计原则,进而分析了大型体育赛事物流信息平台系统结构:中心管理平台结构与模块、赛区物流管理系统、物流服务提供商业务管理系统、供应商业务系统等构成及功能,最后探讨了大型体育赛事物流信息平台可能面临的风险与防范措施.

The rapid expansion of enterprises makes product collaborative design(PCD)a critical issue under the distributed heterogeneous environment,but as the collaborative task of large-scale network becomes more complicated,neither unified task decomposition and allocation methodology nor Agent-based network management platform can satisfy the increasing demands.In this paper,to meet requirements of PCD for distributed product development,a collaborative design mechanism based on the thought of modularity and the Agent technology is presented.First,the top-down 4-tier process model based on task-oriented modular and Agent is constructed for PCD after analyzing the mapping relationships between requirements and functions in the collaborative design.Second,on basis of sub-task decomposition for PCD based on a mixed method,the mathematic model of task-oriented modular based on multi-objective optimization is established to maximize the module cohesion degree and minimize the module coupling degree,while considering the module executable degree as a restriction.The mathematic model is optimized and simulated by the modified PSO,and the decomposed modules are obtained.Finally,the Agent structure model for collaborative design is put forward,and the optimism matching Agents are selected by using similarity algorithm to implement different task-modules by the integrated reasoning and decision-making mechanism with the behavioral model of collaborative design Agents.With the results of experimental studies for automobile collaborative design,the feasibility and efficiency of this methodology of task-oriented modular and Agent-based collaborative design in the distributed heterogeneous environment are verified.On this basis,an integrative automobile collaborative R&D platform is developed.This research provides an effective platform for automobile manufacturing enterprises to achieve PCD,and helps to promote product numeralization collaborative R&D and management development.

通过对当前水务企业普遍存在的投人不足问题的分析,阐述了在市场经济条件下,可以盘活企业存量资产,加强与金融部门合作,通过多种形式的融资,解决水务企业对资金的需求,促进企业的发展.