不理想的枝晶生长、不稳定的固体电解质界面以及循环过程中锂金属体积的无限变化等问题极大地限制了锂金属电池的实际应用。作者设计了亲锂Ti_(3)C_(2)T_(x)-MXene修饰的炭泡沫(Ti_(3)C_(2)T_(x)-MX@CF)来调节锂的成核行为,有效缓解锂...不理想的枝晶生长、不稳定的固体电解质界面以及循环过程中锂金属体积的无限变化等问题极大地限制了锂金属电池的实际应用。作者设计了亲锂Ti_(3)C_(2)T_(x)-MXene修饰的炭泡沫(Ti_(3)C_(2)T_(x)-MX@CF)来调节锂的成核行为,有效缓解锂金属负极的体积变化,获得了高稳定的锂金属电池。其中,三维的CF骨架具有较高的比表面积,不仅降低了局部电流密度来避免浓度极化,而且为缓解循环过程中的体积膨胀提供了足够的空间。更重要的是,丰富的官能团赋予了Ti_(3)C_(2)T_(x)-MX优异的亲锂性,能够有效的降低锂成核过电位,引导锂均匀沉积而不形成锂枝晶,并使负极表面的界面保持稳定。因此,组装的Li-Ti_(3)C_(2)T_(x)-MX@CF对称电池在电流密度为4 mA cm^(-2),容量为1 mAh cm^(-2)时,表现出超过2400 h的良好循环稳定性,过电位低至9 mV。此外,Li-Ti_(3)C_(2)T_(x)-MX@CF||NCM111全电池在1 C下循环330圈后仍能提供129.6 mAh g^(-1)的容量,表明Ti_(3)C_(2)T_(x)-MX对构建稳定的锂金属负极具有重要意义。展开更多
Statistical studies were conducted on the southwest vortex(SWV) during the summers of 2000–13 using high-resolution reanalysis data with a horizontal resolution of 0.5°× 0.5°. A total of 578 SWVs were ...Statistical studies were conducted on the southwest vortex(SWV) during the summers of 2000–13 using high-resolution reanalysis data with a horizontal resolution of 0.5°× 0.5°. A total of 578 SWVs were detected, with a maximum interannual frequency of 55. The variation of the interannual frequency featured a period of around six years. The most active period of SWVs was early July and the maximum occurrence of SWVs appeared in early morning(0200–0800 Beijing Standard Time(BST)). Most of the SWVs were short-lived, with only 66 cases(11.4%) lasting for more than 24 h. In addition, the moving tracks and three-dimensional shape of long-lived(≥ 36 h) SWVs are also presented. For those SWVs that lasted for more than 12 h, four types of SWVs(Types I–IV) were identified using a new method, and the results indicated that the dynamical and thermodynamical conditions before the formation of SWVs are effective indicators of the subsequent evolution of the vortex and associated severe weathers. Moreover, a further level of classification was also constructed for Type II SWVs, which accounted for the largest proportion out of Types I–IV, and the results indicated that the lifespan, radius and maximum 6-h precipitation were all closely related to the intensity of precipitation before the formation of SWVs.展开更多
文摘目的:采用CT定量分析多发性肌炎/皮肌炎相关间质性肺病(Polymyositis/dermatomyositis-associated interstitial lung disease,PM/DM-ILD)患者的肺部改变,探究其评价PM/DM-ILD患者胸部改变的应用价值。方法:收集301例PM/DM-ILD及76例非ILD患者胸部CT图像纳入数字肺分析平台,测量两组研究对象全肺及各肺叶的肺容积、平均肺密度及肺血管体积百分比。利用定量CT肺密度直方图计算高衰减区百分比(Percentage of high attenuation area,HAA%)。采用多元Logistic回归分析筛选与PM/DM-ILD诊断相关的定量参数并构建复合模型。使用受试者工作特征曲线(ROC)及曲线下面积(AUC)确定鉴别诊断PM/DM-ILD组和非ILD组的最佳定量参数及其阈值、并评价复合模型的诊断效能。结果:与非ILD组相比,ILD组全肺及各肺叶的肺容积均明显减小、平均肺密度及HAA%均明显增高,双肺上叶肺血管体积百分比明显增大、而双肺下叶肺血管体积百分比明显减小,差异均具有统计学意义(P<0.05)。多元Logistic回归分析显示右下肺平均密度(OR=1.015,95%CI:1.003~1.028,P=0.019)、右下肺血管体积百分比(OR=0.763,95%CI:0.584~0.997,P=0.047)及年龄(OR=1.025,95%CI:1.003~1.048,P=0.026)对诊断ILD具有统计学意义。ROC曲线分析显示,右下肺平均密度为鉴别诊断PM/DM-ILD组和非ILD组的最佳CT定量参数,AUC为0.84(95%CI:0.80~0.89),以-770.7 HU为阈值,敏感度为78.1%,特异度为77.8%。基于CT定量参数及年龄构建的复合诊断模型具有更佳的诊断效能,AUC为0.87(95%CI:0.83~0.91)。结论:定量CT能够客观准确评估PM/DM-ILD患者肺容积、平均肺密度及肺血管体积改变。基于CT定量参数及年龄构建的复合模型对ILD的识别显示出良好的诊断效能,为PM/DM-ILD患者的病情评估和诊断提供了便捷的新途径。
文摘不理想的枝晶生长、不稳定的固体电解质界面以及循环过程中锂金属体积的无限变化等问题极大地限制了锂金属电池的实际应用。作者设计了亲锂Ti_(3)C_(2)T_(x)-MXene修饰的炭泡沫(Ti_(3)C_(2)T_(x)-MX@CF)来调节锂的成核行为,有效缓解锂金属负极的体积变化,获得了高稳定的锂金属电池。其中,三维的CF骨架具有较高的比表面积,不仅降低了局部电流密度来避免浓度极化,而且为缓解循环过程中的体积膨胀提供了足够的空间。更重要的是,丰富的官能团赋予了Ti_(3)C_(2)T_(x)-MX优异的亲锂性,能够有效的降低锂成核过电位,引导锂均匀沉积而不形成锂枝晶,并使负极表面的界面保持稳定。因此,组装的Li-Ti_(3)C_(2)T_(x)-MX@CF对称电池在电流密度为4 mA cm^(-2),容量为1 mAh cm^(-2)时,表现出超过2400 h的良好循环稳定性,过电位低至9 mV。此外,Li-Ti_(3)C_(2)T_(x)-MX@CF||NCM111全电池在1 C下循环330圈后仍能提供129.6 mAh g^(-1)的容量,表明Ti_(3)C_(2)T_(x)-MX对构建稳定的锂金属负极具有重要意义。
基金supported by a project of the Chengdu Institute of Plateau Meteorology, CMA (Grant No. LPM2011006)the State Grid Science & Technology Project (GC71-13-007)the National Natural Science Foundation of China (Grant Nos. 41205027, 41375053, and 41375058)
文摘Statistical studies were conducted on the southwest vortex(SWV) during the summers of 2000–13 using high-resolution reanalysis data with a horizontal resolution of 0.5°× 0.5°. A total of 578 SWVs were detected, with a maximum interannual frequency of 55. The variation of the interannual frequency featured a period of around six years. The most active period of SWVs was early July and the maximum occurrence of SWVs appeared in early morning(0200–0800 Beijing Standard Time(BST)). Most of the SWVs were short-lived, with only 66 cases(11.4%) lasting for more than 24 h. In addition, the moving tracks and three-dimensional shape of long-lived(≥ 36 h) SWVs are also presented. For those SWVs that lasted for more than 12 h, four types of SWVs(Types I–IV) were identified using a new method, and the results indicated that the dynamical and thermodynamical conditions before the formation of SWVs are effective indicators of the subsequent evolution of the vortex and associated severe weathers. Moreover, a further level of classification was also constructed for Type II SWVs, which accounted for the largest proportion out of Types I–IV, and the results indicated that the lifespan, radius and maximum 6-h precipitation were all closely related to the intensity of precipitation before the formation of SWVs.
