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151.
基于2010年第六次全国人口普查微观数据和夜间灯光数据等,运用多层级logistic回归模型估计中国城镇化水平和速度与老年人自评健康的关联,分析城镇化健康效应在不同老年人群体间的差异,并运用倾向得分匹配方法,控制“自选择”机制对分析结果的干扰。结果表明:1)中国县区城镇化水平和速度与老年人自评健康呈显著正相关关系,居住于城镇化水平中等和城镇化速度较快县区的老年人更可能自评为健康;2)城镇化水平和速度与老年人自评健康的关系在不同受教育程度和户口状态的老年人群体间存在显著差异,城镇化水平和速度对受教育程度较低、持有本地户口老年人健康水平的提升效益更大;3)控制了老年人居住“自选择”的干扰后,县区城镇化水平和速度与老年人自评健康的正向关联依然稳健,表明“自选择偏误”对中国县区城镇化水平和速度与老年人自评健康的关系没有显著的影响。 相似文献
152.
Wu Sha Wang Qing Wang Xu Guo Ruixue Zhang Tongwei Pan Yongxin Li Feng Li Ying 《中国海洋湖沼学报》2021,39(6):2082-2096
Journal of Oceanology and Limnology - Based on analysis of gene structure of mamXY operon in Magnetospirillum gryphiswaldense strain MSR-1, we constructed a mamZ deletion mutant strain (ΔmamZ)... 相似文献
153.
实际用海效益包括海域资源在生产过程中产生的直接经济收益和生态环境系统的负面效应,文章通过建立海洋高质量用海效益评估模型反映和量化实际用海效益,并将该模型在台州市海域应用,研究结果发现,台州市涉海县、市、区中椒江区实际单位用海效益最高为68.85万元/hm2,玉环市最低为4.02万元/ hm2。原因在于椒江区不仅其海域资源价值表现良好,而且生态环境损害程度得到了有效控制。从而得出,海洋经济高质量发展绝对不是海域资源过度使用,也不是海洋生态环境的绝对保护,两者是相互统一、相互协调的,保证海域资源使用价值保值增值是海洋经济合理运行的基础,保护海洋生态环境系统是海域资源使用价值保值增值的根本,这是引导海洋经济高质量发展的重要路径。 相似文献
154.
Social capital has played an increasingly important role in regional development. China is a country with high stocks of social
capital. Using several different indicators of social capital, this study tries to research the regional disparities in social
capital and the influence of social capital on economic growth of China in 1978–2004. Measuring social capital with indicators
of associations, charities and blood donation rates, this study finds significant regional disparities in social capital at
provincial level in China. Those indicators for social capital are highly correlated with regional economic performance. Statistical
analysis shows that social capital has a significant and positive effect on a long-term provincial economic growth. This relationship
exists after controlling policy, macro location factors, and per capita GDP in the initial year. The empirical findings indicate
that institutions, culture and social relations are critical for regional development in China. Therefore, the creation and
support of social capital should be paid more attention to when making regional policy. 相似文献
155.
西安地铁隧道穿越饱和软黄土地段的地表沉降监测 总被引:1,自引:0,他引:1
以西安地铁一号线朝阳门站—康复路站区段饱和软黄土地铁隧道为研究对象,通过施工期现场地表沉降变形监测,分析了在饱和软黄土特殊地层条件下隧道浅埋暗挖法施工引起的该区段地表沉降变形规律以及地表沉降槽分布特征。结果表明:在饱和软黄土隧道开挖时,随着掌子面的推进,隧道顶地表沉降可分为沉降微小阶段、沉降显著发展阶段、沉降缓慢阶段和沉降稳定阶段;单线隧道开挖后的最大地表沉降量为18.89mm,双线隧道开挖后的最大地表沉降量为36.4mm;已开挖隧道对围岩土体的扰动作用使得后开挖隧道的地表沉降发展较大;双线隧道的地表沉降槽宽度接近单线隧道沉降槽宽度的2倍,因此可以将其近似为单线隧道地表沉降槽宽度与双线隧道轴线中点距离之和;单线隧道开挖后地表沉降槽宽度为8.4~9.3m,双线隧道开挖后地表沉降槽宽度为16.2~17.5m;隧道开挖施工的沉降槽宽度参数为0.435~0.467,单线隧道开挖后的地层损失率为0.765%~1.324%,双线隧道开挖后的地层损失率为1.231%~2.200%。 相似文献
156.
Journal of Oceanology and Limnology - The geochemical characteristics and potential controlling factors of colloidal Zn, Cd, and Pb in Huanghe (Yellow) River estuary (HRE), China were investigated.... 相似文献
157.
Arsenic removal from Pinctada martensii enzymatic hydrolysate by using Zr(IV)-loaded chelating resin
The present study investigated the removal of inorganic arsenic from Pinctada martensii enzymatic hydrolysate through unmodified resin (D296) and Zr(IV)-loaded chelating resin (Zr-D401). By loading Zr to macroporous chelating resin D401, the as exchange adsorption active sites are generated. This transforms D401 from a material that does not have the arsenic adsorption capacity into a material that has excellent arsenic exchange adsorption capacity. The static adsorption experiments were conducted to investigate the optimal removal condition for D296 and Zr-D401. The experimental results show that: the optimum condition for D296 is that T= 25°C, pH = 5, resin additive amount = 1 g (50 mL)?1, and contact time = 10 h, the corresponding arsenic removal rate being 65.7%, and protein loss being 2.33%; the optimum condition for Zr-D401 is that T=25°C, pH = 8, resin additive amount = 1 g (50 mL)?1, and contact time=10 h, the corresponding arsenic removal rate being 70.3%, and protein loss being 4.65%. These results show that both of the two resins are effective in arsenic removal for preserving useful substance. Our research provides scientific evidence and advances in the processing technology for heavy metal removal in shellfish. 相似文献
158.
A total of 348 species belonging to 8 phyla and 125 genera were observed in seasonally sampled phytoplankton of tidal rivers from 13 sampling sites around Luoyuan Bay, and all field samplings were carried out in productive period(March/June/August/December) at ebb tide. Bacillariophyta species were the most abundant species, followed by Chlorophyta, Cyanophytes, Euglenophyta, Cryptophyta, Dinophyta, Xanthophyta and Chrysophytas. Seasonal distribution index(SDI) value ranged from 0.63 to 0.86, which meant that species found at those sites in 4 seasons tended to be largely different. Phytoplankton individuals ranged from 5.939×10~4 ind L~(-1) in winter to 75.31×10~4 ind L~(-1) in autumn. Phytoplankton biomass ranged from 0.620 mg L~(-1) in summer to 2.373 mg L~(-1) in autumn. The grey correlation analysis(GCA) showed that the nutrient variables played an important role in the influence on phytoplankton community in every season. The canonical correspondence analysis(CCA) revealed impact of environmental variables on the different species, most of Bacillariophyta species were negative correlation with nutrients(TP and NH_3-N) in the four seasons, Chlorophyta species and Cyanophyta species did not show obvious correlation with environment variables in every season. The combination of GRA analysis and CCA analysis provided a method to quantitatively reveal the correlation between phytoplankton community and environmental variables in water body of tidal rivers at this region. 相似文献
159.
根据厦门东孚井水氡多年的观测资料,分析了水氡异常与地震活动的关系。分析结果认为,该井点映震效果较好,特别是对发生在长乐-诏安断裂带上的地震,映震能力尤为明显。 相似文献
160.
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????????????У????????????乤??????????У??????????????λ??????????????????????????????????λ?????????????????????????ε??????λ??????????????????????Matlab GUI?????????????????????????ò??????????????????????????????????á? 相似文献