美国高速公路安全保险协会(Insurance Institute for Highway Safety,IIHS)2012年颁布的正面小重叠碰撞试验方法及评价规程,对进军美国市场的中国车企提出了挑战。本文根据IIHS协会的试验方法及评价规程,用相关性分析后的有限元模型,对...美国高速公路安全保险协会(Insurance Institute for Highway Safety,IIHS)2012年颁布的正面小重叠碰撞试验方法及评价规程,对进军美国市场的中国车企提出了挑战。本文根据IIHS协会的试验方法及评价规程,用相关性分析后的有限元模型,对某实车进行了正面小重叠碰撞仿真分析。试验中,汽车以64.4km/h的速度撞击刚性壁障,重叠率为25%。试验后对碰撞车的车体结构、约束系统/假人运动学、假人伤害测量三方面进行评价,加权得到正面小重叠碰撞工况的总等级。分析结果为:车体结构得到"边缘"的评级;针对初始结果,从车体结构和材料两方面进行优化,优化后车体结构评级为"良好"。提出结构耐撞性能、约束系统集成方面的建议,为后续车辆安全性能开发提供参考。展开更多
Aims There are numerous grassland ecosystem types on the Tibetan Plateau.These include the alpine meadow and steppe and degraded alpine meadow and steppe.This study aimed at developing a method to estimate aboveground...Aims There are numerous grassland ecosystem types on the Tibetan Plateau.These include the alpine meadow and steppe and degraded alpine meadow and steppe.This study aimed at developing a method to estimate aboveground biomass(AGB)for these grasslands from hyperspectral data and to explore the feasibility of applying air/satellite-borne remote sensing techniques to AGB estimation at larger scales.Methods We carried out a field survey to collect hyperspectral reflectance and AGB for five major grassland ecosystems on the Tibetan Plateau and calculated seven narrow-band vegetation indices and the vegetation index based on universal pattern decomposition(VIUPD)from the spectra to estimate AGB.First,we investigated correlations between AGB and each of these vegetation indices to identify the best estimator of AGB for each ecosystem type.Next,we estimated AGB for the five pooled ecosystem types by developing models containing dummy variables.At last,we compared the predictions of simple regression models and the models containing dummy variables to seek an ecosystem type-independent model to improve prediction of AGB for these various grassland ecosystems from hyperspectral measurements.Important findings When we considered each ecosystem type separately,all eight vegetation indices provided good estimates of AGB,with the best predictor of AGB varying among different ecosystems.When AGB of all the five ecosystems was estimated together using a simple linear model,VIUPD showed the lowest prediction error among the eight vegetation indices.The regression models containing dummy variables predicted AGB with higher accuracy than the simple models,which could be attributed to the dummy variables accounting for the effects of ecosystem type on the relationship between AGB and vegetation index(VI).These results suggest that VIUPD is the best predictor of AGB among simple regression models.Moreover,both VIUPD and the soil-adjusted VI could provide accurate estimates of AGB with dummy variables integrated in regression models.T展开更多
Background:Shenyankangfu Tablet(SYKFT)is a Chinese patent medicine that has been used widely to decrease proteinuria and the progression of chronic kidney disease.Objective:This trial compared the efficacy and safety ...Background:Shenyankangfu Tablet(SYKFT)is a Chinese patent medicine that has been used widely to decrease proteinuria and the progression of chronic kidney disease.Objective:This trial compared the efficacy and safety of SYKFT,for the control of proteinuria in primary glomerulonephritis patients,against the standard drug,losartan potassium.Design,setting,participants and intervention:This was a multicenter,double-blind,randomized,controlled clinical trial.Primary glomerulonephritis patients,aged 18-70 years,with blood pressure≤140/90 mmHg,estimated glomerular filtration rate(eGFR)>45 mL/min per 1.73 ㎡,and 24-hour proteinuria level of 0.5-3.0 g,were recruited in 41 hospitals across 19 provinces in China and were randomly divided into five groups:SYKFT,losartan potassium 50 mg or 100 mg,SYKFT plus losartan potassium 50 mg or 100 mg.Main outcome measu res:The primary outcome was change in the 24-hour proteinuria level,after 48 weeks of treatment.Results:A total of 735 participants were enrolled.The percent decline of urine protein quantification in the SYKFT group after 48 weeks was 8.78%±2.56%(P=0.006)more than that in the losartan 50 mg group,which was 0.51%±2.54%(P=1.000)less than that in the losartan 100 mg group.Compared with the losartan potassium 50 mg group,the SYKFT plus losartan potassium 50 mg group had a 13.39%±2.49%(P<0.001)greater reduction in urine protein level.Compared with the losartan potassium 100 mg group,the SYKFT plus losartan potassium 100 mg group had a 9.77%±2.52%(P=0.001)greater reduction in urine protein.With a superiority threshold of 15%,neither was statistically significant.eGFR,serum creatinine and serum albumin from the baseline did not change statistically significant.The average change in TCM syndrome score between the patients who took SYKFT(-3.00[-6.00,-2.00])and who did not take SYKFT(-2.00[-5.00,0])was statistically significant(P=0.003).No obvious adverse reactions were observed in any group.Conclusion:SYKFT decreased the proteinuria and improved the TCM syndrome scores 展开更多
文摘美国高速公路安全保险协会(Insurance Institute for Highway Safety,IIHS)2012年颁布的正面小重叠碰撞试验方法及评价规程,对进军美国市场的中国车企提出了挑战。本文根据IIHS协会的试验方法及评价规程,用相关性分析后的有限元模型,对某实车进行了正面小重叠碰撞仿真分析。试验中,汽车以64.4km/h的速度撞击刚性壁障,重叠率为25%。试验后对碰撞车的车体结构、约束系统/假人运动学、假人伤害测量三方面进行评价,加权得到正面小重叠碰撞工况的总等级。分析结果为:车体结构得到"边缘"的评级;针对初始结果,从车体结构和材料两方面进行优化,优化后车体结构评级为"良好"。提出结构耐撞性能、约束系统集成方面的建议,为后续车辆安全性能开发提供参考。
基金The field investigation was partly supported by a program on long-term monitoring of alpine ecosystems on the Tibetan Plateau from the Ministry of Environment,Japan to T.Y.Program for New Century Excellent Talents in University to C.J.Director-encouragement fund from National Institute for Environmental Studies to S.A.
文摘Aims There are numerous grassland ecosystem types on the Tibetan Plateau.These include the alpine meadow and steppe and degraded alpine meadow and steppe.This study aimed at developing a method to estimate aboveground biomass(AGB)for these grasslands from hyperspectral data and to explore the feasibility of applying air/satellite-borne remote sensing techniques to AGB estimation at larger scales.Methods We carried out a field survey to collect hyperspectral reflectance and AGB for five major grassland ecosystems on the Tibetan Plateau and calculated seven narrow-band vegetation indices and the vegetation index based on universal pattern decomposition(VIUPD)from the spectra to estimate AGB.First,we investigated correlations between AGB and each of these vegetation indices to identify the best estimator of AGB for each ecosystem type.Next,we estimated AGB for the five pooled ecosystem types by developing models containing dummy variables.At last,we compared the predictions of simple regression models and the models containing dummy variables to seek an ecosystem type-independent model to improve prediction of AGB for these various grassland ecosystems from hyperspectral measurements.Important findings When we considered each ecosystem type separately,all eight vegetation indices provided good estimates of AGB,with the best predictor of AGB varying among different ecosystems.When AGB of all the five ecosystems was estimated together using a simple linear model,VIUPD showed the lowest prediction error among the eight vegetation indices.The regression models containing dummy variables predicted AGB with higher accuracy than the simple models,which could be attributed to the dummy variables accounting for the effects of ecosystem type on the relationship between AGB and vegetation index(VI).These results suggest that VIUPD is the best predictor of AGB among simple regression models.Moreover,both VIUPD and the soil-adjusted VI could provide accurate estimates of AGB with dummy variables integrated in regression models.T
基金supported by the National Science and Technology Major Projects of China(No.2014ZX09201021)Beijing Municipal Science and Technology Commission Major Projects(No.D181100000118002)。
文摘Background:Shenyankangfu Tablet(SYKFT)is a Chinese patent medicine that has been used widely to decrease proteinuria and the progression of chronic kidney disease.Objective:This trial compared the efficacy and safety of SYKFT,for the control of proteinuria in primary glomerulonephritis patients,against the standard drug,losartan potassium.Design,setting,participants and intervention:This was a multicenter,double-blind,randomized,controlled clinical trial.Primary glomerulonephritis patients,aged 18-70 years,with blood pressure≤140/90 mmHg,estimated glomerular filtration rate(eGFR)>45 mL/min per 1.73 ㎡,and 24-hour proteinuria level of 0.5-3.0 g,were recruited in 41 hospitals across 19 provinces in China and were randomly divided into five groups:SYKFT,losartan potassium 50 mg or 100 mg,SYKFT plus losartan potassium 50 mg or 100 mg.Main outcome measu res:The primary outcome was change in the 24-hour proteinuria level,after 48 weeks of treatment.Results:A total of 735 participants were enrolled.The percent decline of urine protein quantification in the SYKFT group after 48 weeks was 8.78%±2.56%(P=0.006)more than that in the losartan 50 mg group,which was 0.51%±2.54%(P=1.000)less than that in the losartan 100 mg group.Compared with the losartan potassium 50 mg group,the SYKFT plus losartan potassium 50 mg group had a 13.39%±2.49%(P<0.001)greater reduction in urine protein level.Compared with the losartan potassium 100 mg group,the SYKFT plus losartan potassium 100 mg group had a 9.77%±2.52%(P=0.001)greater reduction in urine protein.With a superiority threshold of 15%,neither was statistically significant.eGFR,serum creatinine and serum albumin from the baseline did not change statistically significant.The average change in TCM syndrome score between the patients who took SYKFT(-3.00[-6.00,-2.00])and who did not take SYKFT(-2.00[-5.00,0])was statistically significant(P=0.003).No obvious adverse reactions were observed in any group.Conclusion:SYKFT decreased the proteinuria and improved the TCM syndrome scores
