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中国农村劳动力向城镇二三产业转移的长期性分析
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作者 黄宁阳 马强 陈武霞 《湖南农业科学》 2015年第9期107-110,共4页
农村劳动力向城镇二三产业转移是解决我国"三农"问题的重要途径。从人口、经济和制度等方面阐述了我国农村劳动力向城镇二三产业转移是一个长期过程的原因。从人口方面看,我国农村劳动力人口总量大、劳动参与率高以及经济活... 农村劳动力向城镇二三产业转移是解决我国"三农"问题的重要途径。从人口、经济和制度等方面阐述了我国农村劳动力向城镇二三产业转移是一个长期过程的原因。从人口方面看,我国农村劳动力人口总量大、劳动参与率高以及经济活动人口受教育程度低导致农村劳动力转移难度大,任务艰巨。从经济方面看,我国三次产业的就业弹性降低以及三次产业中就业结构与产业结构偏离度较大,也使我国农村劳动力向城镇二三产业转移就业具有长期性。从制度方面看,城乡分割的户籍制度加大了农村劳动力转移成本,延缓了我国农村人口城镇化的进程。 展开更多
关键词 农村劳动力转移 城镇二三产业 长期性分析
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国产SOHM-4型氢钟长期性能分析 被引量:5
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作者 刘峰宇 王宇谱 李锡瑞 《导航定位学报》 CSCD 2020年第5期102-106,116,共6页
针对目前对国产氢原子钟性能评估,尤其是对国产氢钟长期在线运行性能评估相对缺乏的问题,提出1种氢钟性能评估方法:以上海天文台研制的国产SOHM-4型氢钟为例,基于连续相位比,对数据对其性能进行评估;通过分析由频率准确度、频率漂移率... 针对目前对国产氢原子钟性能评估,尤其是对国产氢钟长期在线运行性能评估相对缺乏的问题,提出1种氢钟性能评估方法:以上海天文台研制的国产SOHM-4型氢钟为例,基于连续相位比,对数据对其性能进行评估;通过分析由频率准确度、频率漂移率和频率稳定度指标组成的评估模型,达到对国产氢钟长期在线运行性能精确评估的目的。结果表明,在长达2 a多的连续运行中,国产SOHM-4型氢钟的频率准确度基本优于5×10^-13、频率漂移率优于1×10^-14/d,且线性关系不明显,频率稳定度在±2.5℃温差环境影响下,以天稳计算,大概率处于1×10^-14~2×10^-14之间。 展开更多
关键词 氢原子钟 长期性分析 频率准确度 频率漂移率 频率稳定度
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EXCEL在气相色谱-质谱检测中的应用 被引量:3
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作者 刘玉龙 王苏明 +2 位作者 刘菲 陈宏坤 范俊欣 《岩矿测试》 CAS CSCD 北大核心 2011年第1期116-120,共5页
为了实现自动处理有机色谱分析数据,以Agilent 6890/5973N气相色谱-质谱仪检测地下水中挥发性有机化合物和多环芳烃的数据源为基础,编写了EXCEL应用程序,按批进行数据自动汇总、定性确认和结果计算,设置了对误确认数据的可逆恢复功能;... 为了实现自动处理有机色谱分析数据,以Agilent 6890/5973N气相色谱-质谱仪检测地下水中挥发性有机化合物和多环芳烃的数据源为基础,编写了EXCEL应用程序,按批进行数据自动汇总、定性确认和结果计算,设置了对误确认数据的可逆恢复功能;对实验室空白、野外空白、实验室空白加标、实验室平行样、样品基体加标和质控样品回收率等各项质量控制指标进行统计和评价,并对分析方法长期性能的稳定性进行评价;同时生成质量控制报告,提供向数据库录入数据功能。 展开更多
关键词 气相色谱-质谱法 EXCEL应用 质量控制 分析方法长期性 数据确认
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Analysis and research of long-term stability about the gob site in Northern Shaanxi Province
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作者 ZHANG Zhi-pei PENG Hui 《Journal of Coal Science & Engineering(China)》 2011年第1期16-21,共6页
Based on the analysis of the basic characteristics for the gob site in Northern Shaanxi Province and the room and pillar mining way about coal mine, the variety rule of the coal beds below the site was studied by the ... Based on the analysis of the basic characteristics for the gob site in Northern Shaanxi Province and the room and pillar mining way about coal mine, the variety rule of the coal beds below the site was studied by the using of FEM during the process of coal mining. The statuses of the stresses and strains and the varieties of the plastic area were simulated in the whole rock and coal pillars. The characters of stresses and deformation of the gob area of the coalmine were analyzed and evaluated after the site built in weathering. Moreover, the long-term stability of the gob area was predicted. As a result, the deformation of the gob area under the site is not been finished, and there is the danger that the gob site will collapsing as a whole; therefore, relative measures must be taken. 展开更多
关键词 Northem Shaanxi the gob site room and pillar mining analysis and research of long-term stability numericalsimulation
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Comparison of Design Response Spectrum for Long Period Structures Based on Scenario Earthquakes
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作者 Xu Dandan Lv Yuejun +1 位作者 Chen Yang Pan Long 《Earthquake Research in China》 2014年第3期403-412,共10页
Two kinds of determining methods for scenario earthquakes are presented in this paper,namely the weighted average method and maximum probability method. This paper briefly introduces the two methods,then taking a high... Two kinds of determining methods for scenario earthquakes are presented in this paper,namely the weighted average method and maximum probability method. This paper briefly introduces the two methods,then taking a high-rise building in the Yantai area as a case study,we use the weighted average method and maximum probability method to realize seismic hazard analysis, determine earthquake magnitude, the epicenter and specific space position,and then give two response spectrums of the two methods. By comparing the differences of response spectrums between the two methods,we find that the weighted average method is more suitable for long period structures,while considering long period safety. The maximum probability method is more suitable for short period structures. It is reasonable to choose a corresponding different method when the structures have different natural vibration periods. 展开更多
关键词 Long period Scenario earthquake Weighted average method Maximumprobability method Response spectrum
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