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大坝一等水平位移监测网数据处理流程及精度保障措施
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作者 刘明波 巨天力 李晓鸽 《西北水电》 2024年第3期21-25,41,共6页
大坝水平位移监测网是大坝变形监测的平面基准,监测网的精度关系大坝变形监测结果的可靠性和大坝安全鉴定结论的正确性。为了提高监测网数据处理精度,依托大型水电站大坝监测网复测项目,研究分析相对湿度、斜距化平方法、地球曲率半径... 大坝水平位移监测网是大坝变形监测的平面基准,监测网的精度关系大坝变形监测结果的可靠性和大坝安全鉴定结论的正确性。为了提高监测网数据处理精度,依托大型水电站大坝监测网复测项目,研究分析相对湿度、斜距化平方法、地球曲率半径对边长改化的影响。结果表明:相对湿度修正对边长的影响值最大可达2 ppm,斜距化平时采用高差计算的边长比采用垂直角计算的边长精度高0.05~1.95 ppm,用测区地球平均曲率半径代替测距边法截线地球曲率半径对投影边长的影响值最大可达0.08 ppm;高精度大坝水平位移监测网数据处理时,应用相对湿度修正实测边长,优先选用高差斜距化平,可用测区地球平均曲率半径代替测距边法截线地球曲率半径。研究成果可为类似项目提供有益参考。 展开更多
关键词 水平位移 监测控制网 相对湿度修正 折光系数 地球平均曲率半径
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Nighttime peroxy radicals chemistry at Rishiri Island during the campaign RISFEX 2003
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作者 LIU Yan WANG JiangTao +4 位作者 WANG ZhuQing GONG XiaoDong YANG Bing TAN LiJu QI Bin 《Science China Chemistry》 SCIE EI CAS 2012年第11期2450-2461,共12页
Peroxy radicals (ROx) concentrations were measured by Peroxy Radical Chemical Amplifier (PERCA) technique during the field campaign RISFEX 2003 (RiShifi Fall Experiment 2003), which was performed in September 20... Peroxy radicals (ROx) concentrations were measured by Peroxy Radical Chemical Amplifier (PERCA) technique during the field campaign RISFEX 2003 (RiShifi Fall Experiment 2003), which was performed in September 2003 at Rishiri island (45.07 N, 141.12 E, and 35 m asl) in the sea of Japan. The concentrations of nighttime ROx radicals had temporal variations around an average of 7.9±5.8 (1σ) pptv and showed a positive correlation with the summed mixing ratio of four monoterpene species. Model calculations suggested that local nighttime ROx radicals were dominated by the reactions of monoterpene with ozone (03) and nitrate radical (NO3), contributing ca. 76% and 19%, respectively. The comparisons between the observed ROx and ones modeled had implied that the current model may be overestimated the yields of peroxy radicals from the reactions of monoterpenes with ozone and an important source of peroxy radicals was possibly missed. Abnormal high concentrations of observed ROx radicals were found during high relative humidity (RH) period (especially 〉 95%), and the possible explanation was that the humidity correction of ROx radicals under high RH conditions may be inaccurate and overestimates ROx concen- 展开更多
关键词 peroxy radicals nighttime chemistry MONOTERPENE OZONOLYSIS humidity correction
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