The standard Gibbs energies of transfer (Δ tr G 0) for potassium tetraphenylborate (KBPh 4) have been studied in the systems of water and water +1 propanol (PrOH) as well as water and water + t butyl alcohol (TBA) at...The standard Gibbs energies of transfer (Δ tr G 0) for potassium tetraphenylborate (KBPh 4) have been studied in the systems of water and water +1 propanol (PrOH) as well as water and water + t butyl alcohol (TBA) at 298.15?K. The results show that -Δ tr G 0 exhibits a complicated changing pattern with the mole fraction of TBA( x (TBA)) or PrOH ( x (PrOH)), and Δ tr G 0 has the a maximum value at x (TBA) = 0.2 or x (PrOH)=0.2. Especially, -Δ tr G 0 of KBPh 4 changes unusually with increasing x (TBA) when x (TBA) < 0.05. The reasons for these changes were analyzed and discussed.展开更多
Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision. It is important f...Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision. It is important for certification institutions to explore methods for updating and transferring present standards, to accelerate the transfer of standard information and ensure present standards are implemented in a timely manner.展开更多
选择南水北调中线工程沿线邯郸、正定、涿州为代表地区,利用1979-2021年冬季逐日气温数据,分析各代表区气温序列统计频率分布与理论概率分布的拟合情况,提出标准化温度指数(standardized temperature index,STI),并据此建立新的冬季冷...选择南水北调中线工程沿线邯郸、正定、涿州为代表地区,利用1979-2021年冬季逐日气温数据,分析各代表区气温序列统计频率分布与理论概率分布的拟合情况,提出标准化温度指数(standardized temperature index,STI),并据此建立新的冬季冷暖量化评估模型。结果表明:STI方法与国标法的冬季冷暖评估结果基本一致,但在各代表区强冷冬和强暖冬划定上,STI评估得出的年份数量均少于国标法;各代表区以1月份气温计算得出的冷暖等级阈值对应的气温值均明显低于按整个冬季3个月计算结果。工程所在纬度越高,冬季冷暖等级阈值对应的气温值越低;根据STI评估结果,邯郸、正定、涿州发生强冷冬概率分别为7.14%、9.52%和4.76%,发生弱冷冬及以上的概率分别为38.09%、40.48%和38.09%,发生平冬的概率分别为21.43%、28.57%和21.43%,发生弱暖冬及以上的概率分别为40.48%、30.95%和40.48%,发生强暖冬的概率分别为4.76%、7.14%和2.38%。研究成果与基于正态分布的国标法相比,考虑了气温序列的偏态性概率分布特征,对相对冷暖的判别更科学,有推广应用价值。展开更多
文摘The standard Gibbs energies of transfer (Δ tr G 0) for potassium tetraphenylborate (KBPh 4) have been studied in the systems of water and water +1 propanol (PrOH) as well as water and water + t butyl alcohol (TBA) at 298.15?K. The results show that -Δ tr G 0 exhibits a complicated changing pattern with the mole fraction of TBA( x (TBA)) or PrOH ( x (PrOH)), and Δ tr G 0 has the a maximum value at x (TBA) = 0.2 or x (PrOH)=0.2. Especially, -Δ tr G 0 of KBPh 4 changes unusually with increasing x (TBA) when x (TBA) < 0.05. The reasons for these changes were analyzed and discussed.
文摘Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision. It is important for certification institutions to explore methods for updating and transferring present standards, to accelerate the transfer of standard information and ensure present standards are implemented in a timely manner.
文摘选择南水北调中线工程沿线邯郸、正定、涿州为代表地区,利用1979-2021年冬季逐日气温数据,分析各代表区气温序列统计频率分布与理论概率分布的拟合情况,提出标准化温度指数(standardized temperature index,STI),并据此建立新的冬季冷暖量化评估模型。结果表明:STI方法与国标法的冬季冷暖评估结果基本一致,但在各代表区强冷冬和强暖冬划定上,STI评估得出的年份数量均少于国标法;各代表区以1月份气温计算得出的冷暖等级阈值对应的气温值均明显低于按整个冬季3个月计算结果。工程所在纬度越高,冬季冷暖等级阈值对应的气温值越低;根据STI评估结果,邯郸、正定、涿州发生强冷冬概率分别为7.14%、9.52%和4.76%,发生弱冷冬及以上的概率分别为38.09%、40.48%和38.09%,发生平冬的概率分别为21.43%、28.57%和21.43%,发生弱暖冬及以上的概率分别为40.48%、30.95%和40.48%,发生强暖冬的概率分别为4.76%、7.14%和2.38%。研究成果与基于正态分布的国标法相比,考虑了气温序列的偏态性概率分布特征,对相对冷暖的判别更科学,有推广应用价值。
