科创中国

利用广州南沙区气象探测基地2010年O3浓度和常规气象观测资料,分析了O3浓度变化特征及其气象因子的关系.结果表明,广州南沙区2010年O3浓度最高时均值的最大值出现在8月,超标时数最多的是9月;O3浓度日变化呈单峰型分布,O3浓度日变化最大的季节是秋季,其次为夏季、春季、冬季;O3浓度呈现秋季〉春季〉夏季〉冬季的变化特征.气温、相对湿度、日照时数和云量与O3浓度相关系数大,是影响南沙O3浓度的主要气象因子.秋季O3浓度高,O3主要以局地光化学反应生成为主;春季、夏季和冬季O3主要以外来源的输送为主.气团后向轨迹分析表明南沙区秋季气团主要来自污染的大陆地区,春季、夏季和冬季气团主要是来自东南沿海附近或较为清洁的南海.

Quadruped robots consume a lot of energy,which is one of the factors restricting their application.Energy efficiency is one of the key evaluating indicators for walking robots.The relationship between energy and elastic elements of walking robots have been studied,but different walking gait patterns and contact status have important influences on locomotion energy efficiency,and the energy efficiency considering the foot-end trajectory has not been reported.Therefore,the energy consumption and energy efficiency of quadruped robot with trot gait and combined cycloid foot trajectory are studied.The forward and inverse kinematics of quadruped robot is derived.The combined cycloid function is proposed to generate horizontal and vertical foot trajectory respectively,which can ensure the acceleration curve of the foot-end smoother and more successive,and reduce the contact force between feet and environment.Because of the variable topology mechanism characteristic of quadruped robot,the leg state is divided into three different phases which are swing phase,transition phase and stance phase during one trot gait cycle.The non-continuous variable constraint between feet and environment of quadruped robot is studied.The dynamic model of quadruped robot is derived considering the variable topology mechanism characteristic,the periodic contact and elastic elements of the robot.The total energy consumption of walking robot during one gait cycle is analyzed based on the dynamic model.The specific resistance is used to evaluate energy efficiency of quadruped robot.The calculation results show the relationships between specific resistance and gait parameters,which can be used to determine the reasonable gait parameters.

Wear is a major factor of disc cutters' failure. No current theory offers a standard for the prediction of disc cutter wear yet. In the field the wear prediction method commonly used is based on the excavation length of tunnel boring machine(TBM) to predict the disc cutter wear and its wear law, considering the location number of each disc cutter on the cutterhead(radius for installation); in theory, there is a prediction method of using arc wear coefficient. However, the preceding two methods have their own errors, with their accuracy being 40% or so and largely relying on the technicians' experience. Therefore, radial wear coefficient, axial wear coefficient and trajectory wear coefficient are defined on the basis of the operating characteristics of TBM. With reference to the installation and characteristics of disc cutters, those coefficients are modified according to penetration, which gives rise to the presentation of comprehensive axial wear coefficient, comprehensive radial wear coefficient and comprehensive trajectory wear coefficient. Calculation and determination of wear coefficients are made with consideration of data from a segment of TBM project(excavation length 173 m). The resulting wear coefficient values, after modification, are adopted to predict the disc cutter wear in the follow-up segment of the TBM project(excavation length of 5621 m). The prediction results show that the disc cutter wear predicted with comprehensive radial wear coefficient and comprehensive trajectory wear coefficient are not only accurate(accuracy 16.12%) but also highly congruous, whereas there is a larger deviation in the prediction with comprehensive axial wear coefficient(accuracy 41%, which is in agreement with the prediction of disc cutters' life in the field). This paper puts forth a new method concerning prediction of life span and wear of TBM disc cutters as well as timing for replacing disc cutters.