开发了一种在温和条件下利用可见光催化合成3-酰基吲哚类化合物的新方法。这一过程在常温下进行,使用吲哚和α-酮酸作为起始原料,以g-C_(3)N_(4)作为光催化剂。在20 W 460 nm波长的蓝色LED灯照射下,成功合成了多种3-酰基吲哚衍生物,其...开发了一种在温和条件下利用可见光催化合成3-酰基吲哚类化合物的新方法。这一过程在常温下进行,使用吲哚和α-酮酸作为起始原料,以g-C_(3)N_(4)作为光催化剂。在20 W 460 nm波长的蓝色LED灯照射下,成功合成了多种3-酰基吲哚衍生物,其中最高产率达到了88%。此外,该催化剂可以循环使用至少6次而没有明显的活性损失。此合成策略不仅底物适用性广泛,而且成本效益高,为3-酰基吲哚衍生物的合成提供了一种经济而简便的新途径。展开更多
A set of standard chronologies for tree-ring width(TRW),earlywood width(EWW)and latewood width(LWW)in Pinus tabuliformis Carr.along an altitudi-nal gradient(1450,1400,and 1350 m a.s.l.)on Baiyunshan Mountain,Central C...A set of standard chronologies for tree-ring width(TRW),earlywood width(EWW)and latewood width(LWW)in Pinus tabuliformis Carr.along an altitudi-nal gradient(1450,1400,and 1350 m a.s.l.)on Baiyunshan Mountain,Central China to analyze the effect of varying temperature and precipitation on growth along the gradi-ent.Correlation analyses showed that at all three altitudes and the TRW and EWW chronologies generally had signifi-cant negative correlations with mean and maximum tem-peratures in the current April and May and with minimum temperatures in the prior July and August,but significant positive correlations with precipitation in the current May.Correlations were generally significantly negative between LWW chronologies and all temperatures in the prior July and August,indicating that the prior summer temperature had a strong lag effect on the growth of P.tabuliformis that increased with altitude.The correlation with the standard-ized precipitation evapotranspiration index(SPEI)confirmed that wet conditions in the current May promoted growth of TR and EW at all altitudes.Significant altitudinal differences were also found;at 1400 m,there were significant positive correlations between EWW chronologies and SPEI in the current April and significant negative correlations between LWW chronologies and SPEI in the current September,but these correlations were not significant at 1450 m.At 1350 m,there were also significant negative correlations between the TRW and the EWW chronologies and SPEI in the prior October and the current July and between LWW chronology and SPEI in the current August,but these cor-relations were not significant at 1400 m.Moving correlation results showed a stable response of EWW in relation to the SPEI in the current May at all three altitudes and of LWW to maximum temperature in the prior July-August at 1400 m from 2002 to 2018.The EWW chronology at 1400 m and the LWW chronology at 1450 m were identified as more suitable for climate reconstruction.These results provide a strong scientific basis for forest management decisions and climate reconstructions in Central China.展开更多
文摘开发了一种在温和条件下利用可见光催化合成3-酰基吲哚类化合物的新方法。这一过程在常温下进行,使用吲哚和α-酮酸作为起始原料,以g-C_(3)N_(4)作为光催化剂。在20 W 460 nm波长的蓝色LED灯照射下,成功合成了多种3-酰基吲哚衍生物,其中最高产率达到了88%。此外,该催化剂可以循环使用至少6次而没有明显的活性损失。此合成策略不仅底物适用性广泛,而且成本效益高,为3-酰基吲哚衍生物的合成提供了一种经济而简便的新途径。
基金This research was funded by National Key Research and Development Program of China(No.2018YFA0605601)National Natural Science Foundation of China(No.42077417,41671042).
文摘A set of standard chronologies for tree-ring width(TRW),earlywood width(EWW)and latewood width(LWW)in Pinus tabuliformis Carr.along an altitudi-nal gradient(1450,1400,and 1350 m a.s.l.)on Baiyunshan Mountain,Central China to analyze the effect of varying temperature and precipitation on growth along the gradi-ent.Correlation analyses showed that at all three altitudes and the TRW and EWW chronologies generally had signifi-cant negative correlations with mean and maximum tem-peratures in the current April and May and with minimum temperatures in the prior July and August,but significant positive correlations with precipitation in the current May.Correlations were generally significantly negative between LWW chronologies and all temperatures in the prior July and August,indicating that the prior summer temperature had a strong lag effect on the growth of P.tabuliformis that increased with altitude.The correlation with the standard-ized precipitation evapotranspiration index(SPEI)confirmed that wet conditions in the current May promoted growth of TR and EW at all altitudes.Significant altitudinal differences were also found;at 1400 m,there were significant positive correlations between EWW chronologies and SPEI in the current April and significant negative correlations between LWW chronologies and SPEI in the current September,but these correlations were not significant at 1450 m.At 1350 m,there were also significant negative correlations between the TRW and the EWW chronologies and SPEI in the prior October and the current July and between LWW chronology and SPEI in the current August,but these cor-relations were not significant at 1400 m.Moving correlation results showed a stable response of EWW in relation to the SPEI in the current May at all three altitudes and of LWW to maximum temperature in the prior July-August at 1400 m from 2002 to 2018.The EWW chronology at 1400 m and the LWW chronology at 1450 m were identified as more suitable for climate reconstruction.These results provide a strong scientific basis for forest management decisions and climate reconstructions in Central China.
