Early hydration mechanism of cement-based materials with silica fume, nano-SiO2 and silica sol of different contents was investigated, and the detailed effect of these Si-rich mineral admixtures in three stages of ear...Early hydration mechanism of cement-based materials with silica fume, nano-SiO2 and silica sol of different contents was investigated, and the detailed effect of these Si-rich mineral admixtures in three stages of early hydration（NG, I, D） using kinetics model was focused. The results showed that silica fume, nano-SiO2, and silica sol have significant effect on kinetic parameters n, k1, k2 and k3, the fineness and existing form of SiO2 particles in these Si-rich mineral admixtures are two important factors to affect the hydration process and on the parameters. Through integrated use of methods of hydration heat-Krstulovic-Dabic Modelsynthetical thermal analysis, data of hydration heat were collected, hydration degree was characterized, as well as the resulting crystallization behavior of early hydration, to build a numerical relationship between parameter n and CH contents that n decreases with increasing CH, and thus, a direct connection between hydration heat release behavior and crystallization behavior has been established.展开更多
Reliable national estimates of CH_4 emissions from natural wetlands depend on model validation based on site observations.We therefore evaluated the performance of the CH_4 MODwetlandmodel in simulating CH_4 emissions...Reliable national estimates of CH_4 emissions from natural wetlands depend on model validation based on site observations.We therefore evaluated the performance of the CH_4 MODwetlandmodel in simulating CH_4 emissions from 11 representative wetland sites in five regions of China.Model performance analysis showed that this method effectively simulates differences in the CH_4 fluxes between different sites and regions.The model efficiency for estimating the daily CH_4 fluxes in the northeastern China（NE）,Inner Mongolia and northwestern China（NW）,the North China plain and the Middle-Lower Yangtze Plain（E） and the Qinghai Tibetan Plateau（SW） was 0.51,0.20,0.52 and 0.65,respectively.The efficiency for estimating the annual mean CH_4 fluxes in southern China（S） was 0.99.Systematic negative deviation between the simulated and observed CH_4 emissions existed in all regions,especially in the NW region,which had a mean deviation（RMD） value of-36.7%.On the national scale,the root mean square error（RMSE）,the RMD,the model efficiency（EF）between the simulated and observed seasonal values were 28.7%,-7.8% and 0.93,respectively.The CH_4 emissions showed the highest sensitivity to air temperature in the NE and SW regions,and to water table depth in the E region.Based on the sensitivity analysis,future climate warming and wetting are likely to increase the wetland CH_4 emissions at different levels in all regions of China.展开更多
目的 应用疾病诊断相关分组(diagnosis related groups,DRG)预分组模型预测分组结果,掌握国家医疗保障疾病诊断相关分组(China healthcare security diagnosis related groups,CHS-DRG)细分组1.0修订版医保编码2.0分组方案详细规则,做...目的 应用疾病诊断相关分组(diagnosis related groups,DRG)预分组模型预测分组结果,掌握国家医疗保障疾病诊断相关分组(China healthcare security diagnosis related groups,CHS-DRG)细分组1.0修订版医保编码2.0分组方案详细规则,做好临床DRG前期的指导工作,提高病案首页诊断和手术编码正确率。方法 依据分组方案的思路和流程,通过Excel函数公式建立诊断、手术与DRG对应关系,以某院2021年9月—2022年8月出院病案首页数据为预测数据,采用独立样本t检验(independent-samples t test)对预测与分组结果进行对比分析。结果 DRG分组预测模型预测结果与医保分组结果的总体总权重符合率、分组符合率、DRG组数中组别符合率均高于99%,通过对总权重、CMI值与DRG组数对比分析,预测结果与医保分组无显著性差异。结论 预分组模型对某院预测DRG分组具有较强的实用价值,具有可行性。展开更多
基金Funded by the National Key Research Program(973 Program)(No.2015CB655101)the National Natural Science Foundation of China(No.51379163)
文摘Early hydration mechanism of cement-based materials with silica fume, nano-SiO2 and silica sol of different contents was investigated, and the detailed effect of these Si-rich mineral admixtures in three stages of early hydration（NG, I, D） using kinetics model was focused. The results showed that silica fume, nano-SiO2, and silica sol have significant effect on kinetic parameters n, k1, k2 and k3, the fineness and existing form of SiO2 particles in these Si-rich mineral admixtures are two important factors to affect the hydration process and on the parameters. Through integrated use of methods of hydration heat-Krstulovic-Dabic Modelsynthetical thermal analysis, data of hydration heat were collected, hydration degree was characterized, as well as the resulting crystallization behavior of early hydration, to build a numerical relationship between parameter n and CH contents that n decreases with increasing CH, and thus, a direct connection between hydration heat release behavior and crystallization behavior has been established.
基金supported by the Chinese Academy of Sciences(CAS) strategic pilot technology special funds(No.XDA05020204)the National Natural Science Foundation of China(Nos.31000234,41321064 and 41573069)the Climate Change Special Foundation of China Meteorological Administration(No.CCSF201604)
文摘Reliable national estimates of CH_4 emissions from natural wetlands depend on model validation based on site observations.We therefore evaluated the performance of the CH_4 MODwetlandmodel in simulating CH_4 emissions from 11 representative wetland sites in five regions of China.Model performance analysis showed that this method effectively simulates differences in the CH_4 fluxes between different sites and regions.The model efficiency for estimating the daily CH_4 fluxes in the northeastern China（NE）,Inner Mongolia and northwestern China（NW）,the North China plain and the Middle-Lower Yangtze Plain（E） and the Qinghai Tibetan Plateau（SW） was 0.51,0.20,0.52 and 0.65,respectively.The efficiency for estimating the annual mean CH_4 fluxes in southern China（S） was 0.99.Systematic negative deviation between the simulated and observed CH_4 emissions existed in all regions,especially in the NW region,which had a mean deviation（RMD） value of-36.7%.On the national scale,the root mean square error（RMSE）,the RMD,the model efficiency（EF）between the simulated and observed seasonal values were 28.7%,-7.8% and 0.93,respectively.The CH_4 emissions showed the highest sensitivity to air temperature in the NE and SW regions,and to water table depth in the E region.Based on the sensitivity analysis,future climate warming and wetting are likely to increase the wetland CH_4 emissions at different levels in all regions of China.
文摘目的 应用疾病诊断相关分组(diagnosis related groups,DRG)预分组模型预测分组结果,掌握国家医疗保障疾病诊断相关分组(China healthcare security diagnosis related groups,CHS-DRG)细分组1.0修订版医保编码2.0分组方案详细规则,做好临床DRG前期的指导工作,提高病案首页诊断和手术编码正确率。方法 依据分组方案的思路和流程,通过Excel函数公式建立诊断、手术与DRG对应关系,以某院2021年9月—2022年8月出院病案首页数据为预测数据,采用独立样本t检验(independent-samples t test)对预测与分组结果进行对比分析。结果 DRG分组预测模型预测结果与医保分组结果的总体总权重符合率、分组符合率、DRG组数中组别符合率均高于99%,通过对总权重、CMI值与DRG组数对比分析,预测结果与医保分组无显著性差异。结论 预分组模型对某院预测DRG分组具有较强的实用价值,具有可行性。
