针对地质灾害易发性评价因子分级数不确定的问题,引入自适应膨胀因子模糊覆盖分级方法(fuzzy cover approach for clustering based on adaptive inflation factor,AIFFC)对易发性评价因子分级进行优化。以湖南省湘乡市为研究区,提取了...针对地质灾害易发性评价因子分级数不确定的问题,引入自适应膨胀因子模糊覆盖分级方法(fuzzy cover approach for clustering based on adaptive inflation factor,AIFFC)对易发性评价因子分级进行优化。以湖南省湘乡市为研究区,提取了坡度、坡向、高程、年平均降雨量、归一化植被指数、道路、断层、岩性和土地利用9类评价因子,运用AIFFC及自然断点法(natural breakpoint classification,NBC)对连续型因子进行分级,并分别代入加权信息量模型和随机森林模型,获取研究区易发性区划图。采用单因子分级结果精度、灾积比分析和易发性分区结果对AIFFC分级法的优越性进行检验,结果表明:各因子采用AIFFC算法分级的AUC值均高于自然断点法;基于AIFFC的随机森林模型及加权信息量模型的高易发区灾积比分别提升了56.3%、74.6%,低易发区灾积比分别降低了48%、58.1%,AUC值分别提升了7.6%、2.7%。采用AIFFC分级方法优化了地质灾害易发性评价因子分级,显著提高了地质灾害易发性评价的合理性。展开更多
A hydrotalcite with Mg/Al molar ratio 2 was prepared by co-precipitation method and was characterized by XRD, TG/DTA, Zeta potential and BET surface area. The hydrotalcite was calcined at 500℃, with the dehydration f...A hydrotalcite with Mg/Al molar ratio 2 was prepared by co-precipitation method and was characterized by XRD, TG/DTA, Zeta potential and BET surface area. The hydrotalcite was calcined at 500℃, with the dehydration from interlayer, the dehydroxilation from the brucite-like layer and the decomposition of carbonate successively, transformed into the mixed oxide type. The removal of thiocyanate from aqueous solution by using the original hydrotalcite and calcined hydrotalcite(HTC-500) was investigated. The results showed that the thiocyanate adsorption capacity of calcined hydrotalcite was much higher than that of the original form. Calcined hydrotalcite was particularly effective at removing thiocyanate, and that the effective range of pH for the thiocyanate removal are between 5.5—10.0. The experimental data of thiocyanate removal fit nicely with Langmuir isotherm, and the saturated adsorption uptake was 96.2 mg SCN-/g HTC-500. The adsorption of thiocyanate by calcined hydrotalcite follows first-order kinetics. And the intercalation to the structure recovery for calcined hydrotalcite. But the presence of additional anions could affect the adsorption behavior of thiocyanate.展开更多
目的探讨BMI对首次急性卒中住院患者3个月预后的影响。方法基于多中心、连续性、前瞻性登记研究——中国卒中患者营养调查(investigation of nutrition status in stroke patients of China,INSIS),连续收集首次急性卒中(发病7 d内)住...目的探讨BMI对首次急性卒中住院患者3个月预后的影响。方法基于多中心、连续性、前瞻性登记研究——中国卒中患者营养调查(investigation of nutrition status in stroke patients of China,INSIS),连续收集首次急性卒中(发病7 d内)住院患者的资料,包括年龄、性别、受教育程度、医疗保险等一般资料,脑血管病危险因素,以及入院时BMI、NIHSS评分、住院期间肺炎等临床资料。随访发病3个月后mRS评分,mRS评分0~2分为预后良好。根据入院时BMI将患者分为4组:低BMI组(BMI<18.5 kg/m^(2))、正常BMI组(18.5 kg/m^(2)≤BMI<24.0 kg/m^(2))、超重组(24.0 kg/m^(2)≤BMI<28.0 kg/m^(2))及肥胖组(BMI≥28.0 kg/m^(2))。采用logistic回归分析BMI对卒中发病3个月结局的影响。结果共733例患者纳入本研究,平均年龄(63.5±12.8)岁,女性259例(35.3%),脑出血者181例(24.7%),入院时平均NIHSS评分(7.85±6.45)分,平均BMI为(24.67±3.59)kg/m^(2)。低BMI组22例(3.0%),正常BMI组303例(41.3%),超重组291例(39.7%),肥胖组117例(16.0%)。4组间平均年龄、性别分布、受教育程度、高脂血症发生率、入院时NIHSS评分、是否存在吞咽障碍等指标差异具有统计学意义,其他指标4组间整体差异未达统计学意义。校正混杂因素之后,与正常BMI相比,低BMI、超重或肥胖均对患者发病3个月预后没有独立影响。结论在本研究人群中,与正常BMI相比,入院时低BMI、超重、肥胖对3个月卒中结局无显著影响。展开更多
文摘针对地质灾害易发性评价因子分级数不确定的问题,引入自适应膨胀因子模糊覆盖分级方法(fuzzy cover approach for clustering based on adaptive inflation factor,AIFFC)对易发性评价因子分级进行优化。以湖南省湘乡市为研究区,提取了坡度、坡向、高程、年平均降雨量、归一化植被指数、道路、断层、岩性和土地利用9类评价因子,运用AIFFC及自然断点法(natural breakpoint classification,NBC)对连续型因子进行分级,并分别代入加权信息量模型和随机森林模型,获取研究区易发性区划图。采用单因子分级结果精度、灾积比分析和易发性分区结果对AIFFC分级法的优越性进行检验,结果表明:各因子采用AIFFC算法分级的AUC值均高于自然断点法;基于AIFFC的随机森林模型及加权信息量模型的高易发区灾积比分别提升了56.3%、74.6%,低易发区灾积比分别降低了48%、58.1%,AUC值分别提升了7.6%、2.7%。采用AIFFC分级方法优化了地质灾害易发性评价因子分级,显著提高了地质灾害易发性评价的合理性。
文摘A hydrotalcite with Mg/Al molar ratio 2 was prepared by co-precipitation method and was characterized by XRD, TG/DTA, Zeta potential and BET surface area. The hydrotalcite was calcined at 500℃, with the dehydration from interlayer, the dehydroxilation from the brucite-like layer and the decomposition of carbonate successively, transformed into the mixed oxide type. The removal of thiocyanate from aqueous solution by using the original hydrotalcite and calcined hydrotalcite(HTC-500) was investigated. The results showed that the thiocyanate adsorption capacity of calcined hydrotalcite was much higher than that of the original form. Calcined hydrotalcite was particularly effective at removing thiocyanate, and that the effective range of pH for the thiocyanate removal are between 5.5—10.0. The experimental data of thiocyanate removal fit nicely with Langmuir isotherm, and the saturated adsorption uptake was 96.2 mg SCN-/g HTC-500. The adsorption of thiocyanate by calcined hydrotalcite follows first-order kinetics. And the intercalation to the structure recovery for calcined hydrotalcite. But the presence of additional anions could affect the adsorption behavior of thiocyanate.
文摘目的探讨BMI对首次急性卒中住院患者3个月预后的影响。方法基于多中心、连续性、前瞻性登记研究——中国卒中患者营养调查(investigation of nutrition status in stroke patients of China,INSIS),连续收集首次急性卒中(发病7 d内)住院患者的资料,包括年龄、性别、受教育程度、医疗保险等一般资料,脑血管病危险因素,以及入院时BMI、NIHSS评分、住院期间肺炎等临床资料。随访发病3个月后mRS评分,mRS评分0~2分为预后良好。根据入院时BMI将患者分为4组:低BMI组(BMI<18.5 kg/m^(2))、正常BMI组(18.5 kg/m^(2)≤BMI<24.0 kg/m^(2))、超重组(24.0 kg/m^(2)≤BMI<28.0 kg/m^(2))及肥胖组(BMI≥28.0 kg/m^(2))。采用logistic回归分析BMI对卒中发病3个月结局的影响。结果共733例患者纳入本研究,平均年龄(63.5±12.8)岁,女性259例(35.3%),脑出血者181例(24.7%),入院时平均NIHSS评分(7.85±6.45)分,平均BMI为(24.67±3.59)kg/m^(2)。低BMI组22例(3.0%),正常BMI组303例(41.3%),超重组291例(39.7%),肥胖组117例(16.0%)。4组间平均年龄、性别分布、受教育程度、高脂血症发生率、入院时NIHSS评分、是否存在吞咽障碍等指标差异具有统计学意义,其他指标4组间整体差异未达统计学意义。校正混杂因素之后,与正常BMI相比,低BMI、超重或肥胖均对患者发病3个月预后没有独立影响。结论在本研究人群中,与正常BMI相比,入院时低BMI、超重、肥胖对3个月卒中结局无显著影响。
