In the novel approach to the diagnostic tests of continuous welded rail （CWR） track by the use of the tamping machine, the fundamental statement related to the recording of the curvature with a definite value of the...In the novel approach to the diagnostic tests of continuous welded rail （CWR） track by the use of the tamping machine, the fundamental statement related to the recording of the curvature with a definite value of the lateral displacement being subjected to verification, can provide a basis for the determination of the longitudinal axial force in the rail. An attempt has also been made to define an alternative factor which by means of the measured signals, could be used for the determination of the axial forces in the rail sections. A power engineering approach has been adopted to this concept. Within the framework of the experimental investigations, measurements were carried out in the track test section. The investigations were based on stretching the rail sections by stretchers and on lateral displacements of the track by the tamping machine. The operation of the measuring apparatus was also tested in the experimental railway track section while carrying out the geometrical adjustments by the tamping machine. As a result of next series of the investigation carried out in 2006-2007, the authors worked out a procedure of estimating the longitudinal forces in rails of CWR track.展开更多
为认识西北地区的云水资源(Cloud Water Resource,简称CWR)特征以及科学规划人工增雨开发空中水资源作业布局,利用2000—2019年中国1°×1°CWR观测诊断评估数据集,采用线性拟合和经验正交函数分解(EOF)等方法,统计分析了...为认识西北地区的云水资源(Cloud Water Resource,简称CWR)特征以及科学规划人工增雨开发空中水资源作业布局,利用2000—2019年中国1°×1°CWR观测诊断评估数据集,采用线性拟合和经验正交函数分解(EOF)等方法,统计分析了西北地区CWR的分布及演变气候特征。结果表明:(1)从全区整体看,CWR的相关物理量(状态量、平流量、总量和降水效率)主要表现为夏季最高,春、秋季次之,冬季最低的季节变化特征。其中,春季CWR总量约为1736亿t(折合柱水量约为51.2 mm),仅次于夏季;春季水凝物降水效率为48.7%,相较于秋季,春季的CWR开发潜力更大。(2)从区域内1°×1°网格的计算结果得到空间分布,受地势与环流的影响,近20年CWR年总量及水汽年总量、水凝物年总量的多年平均空间分布呈“两高一低”的特征,高值位于西风急流区与季风影响边缘区,低值区主要位于高原气候区。(3)近20年,西北地区格点的CWR年总量平均以23.6 mm/a速率增加,其中春季的增加趋势最显著,增速为8.5 mm/a。季节分布上,CWR夏季最多,春、秋季次之,冬季最少;水凝物降水效率夏季高,秋、春季较低,冬季最低。(4)CWR年总量的EOF分解第一模态(EOF1)贡献率为78.2%,分布特征为区域东部较高,在2008年出现年际转折,开始转变为CWR东部多、西部少的分布格局。(5)在西北地区典型区域中,天山区域年平均及格点平均后的CWR年总量以及水凝物降水效率均高于祁连山区,年际变化上祁连山区的CWR在增多,天山区的在减少。展开更多
Freely movable wave energy converters(WECs) will greatly improve their adaptability to the marine environment.In this paper, a dual-mode oscillating water column(OWC) WEC with potential sailing capability is proposed....Freely movable wave energy converters(WECs) will greatly improve their adaptability to the marine environment.In this paper, a dual-mode oscillating water column(OWC) WEC with potential sailing capability is proposed. By opening and closing a gate on the side facing the waves, the WEC converts wave energy in the vertical duct(called VD mode) with low sailing resistance or in the backward bend duct(called BBD mode) with high sailing resistance.A small model and a medium model were designed and manufactured. The capture width ratio(CWR) of the small model in the two modes was experimentally studied. The CWR under bidirectional airflow and conversion characteristics under unidirectional airflow of the medium model in the BBD mode were obtained. Tests of the small model show that the peak CWR is 145.2% under regular waves and 90.1% under random waves in BBD mode, and in VD mode the peak CWR is about 60% of that in the BBD mode. Tests of the medium model show that the peak CWR is 228.96% under regular waves, the maximum wave-to-battery efficiency is 63.36% under regular waves and 30.17%under random waves, respectively.展开更多
文摘In the novel approach to the diagnostic tests of continuous welded rail （CWR） track by the use of the tamping machine, the fundamental statement related to the recording of the curvature with a definite value of the lateral displacement being subjected to verification, can provide a basis for the determination of the longitudinal axial force in the rail. An attempt has also been made to define an alternative factor which by means of the measured signals, could be used for the determination of the axial forces in the rail sections. A power engineering approach has been adopted to this concept. Within the framework of the experimental investigations, measurements were carried out in the track test section. The investigations were based on stretching the rail sections by stretchers and on lateral displacements of the track by the tamping machine. The operation of the measuring apparatus was also tested in the experimental railway track section while carrying out the geometrical adjustments by the tamping machine. As a result of next series of the investigation carried out in 2006-2007, the authors worked out a procedure of estimating the longitudinal forces in rails of CWR track.
基金financially supported by the National Natural Science Foundation of China (Grant Nos. 51879253 and U20A20106)。
文摘Freely movable wave energy converters(WECs) will greatly improve their adaptability to the marine environment.In this paper, a dual-mode oscillating water column(OWC) WEC with potential sailing capability is proposed. By opening and closing a gate on the side facing the waves, the WEC converts wave energy in the vertical duct(called VD mode) with low sailing resistance or in the backward bend duct(called BBD mode) with high sailing resistance.A small model and a medium model were designed and manufactured. The capture width ratio(CWR) of the small model in the two modes was experimentally studied. The CWR under bidirectional airflow and conversion characteristics under unidirectional airflow of the medium model in the BBD mode were obtained. Tests of the small model show that the peak CWR is 145.2% under regular waves and 90.1% under random waves in BBD mode, and in VD mode the peak CWR is about 60% of that in the BBD mode. Tests of the medium model show that the peak CWR is 228.96% under regular waves, the maximum wave-to-battery efficiency is 63.36% under regular waves and 30.17%under random waves, respectively.
