The fluorozirconate glasses ZBLANP( ZrF\-4-BaF\-2-LaF\-3-AlF\-3-NaF-PbF\-2) doped with different Yb\+ 3+ concentration were prepared. The Raman spectra and absorption spectra are measured to substantiate the existenc...The fluorozirconate glasses ZBLANP( ZrF\-4-BaF\-2-LaF\-3-AlF\-3-NaF-PbF\-2) doped with different Yb\+ 3+ concentration were prepared. The Raman spectra and absorption spectra are measured to substantiate the existence of phonon-assisted emission. After analyzing the normalized absorption spectra of samples with different Yb\+ 3+-doped concentration, we calculated the maximum cooling effect in the 3 wt% Yb\+ 3+-doped sample pumped at 1 012.5 nm. The corresponding cooling capability is about -4.09 ℃/W and the cooling efficiency reaches 1.76%.展开更多
Rice grain yield and quality declines are due to unsuitable temperatures from wide regions and various sowing dates.This study aimed to evaluate the effects of temperature on rice yield and quality at different phenol...Rice grain yield and quality declines are due to unsuitable temperatures from wide regions and various sowing dates.This study aimed to evaluate the effects of temperature on rice yield and quality at different phenological periods and obtain suitable temperatures for phenological periods in the Yangtze River Basin,China.This study conducted experiments on different sowing dates under different areas in the Yangtze River Basin to observe and compare the differences in rice growth,yield,and quality,controlling for regional varieties.The results showed significant differences in rice growth,yield,and quality among sowing dates and areas,which were related to the average daily temperature during the vegetative period(VT)and the first 20 days of the grain-filling period(GT20).In addition,there was a smaller variation in the average daily temperature in the reproductive period(RT)than in the two phenological periods.Therefore,according to the VT and GT20 thresholds of different yields and qualities,the experimental results were divided into four scenarios(Ⅰ,Ⅱ,Ⅲ,andⅣ)in this study.In Scenario I,high head rice production(rice grain yield multiplied by head rice rate)and rice quality could be obtained.The head rice production of ScenariosⅢandⅣwas lower than that of ScenarioⅠ,by 30.1 and 27.6%,respectively.In Scenario II,the head rice production increased insignificantly while the chalky grain rate and chalkiness were 50.6 and 56.3%higher than those of Scenario I.In conclusion,the Scenario I combination with VT ranges of 22.8-23.9℃and GT20 ranges of 24.2-27.0℃or the combination with VT ranges of 23.9-25.3℃and GT20 ranges of 24.2-24.9℃,which can be obtained by adjusting sowing date and selecting rice varieties with suitable growth periods,is recommended to achieve high levels of rice grain yield and quality in the Yangtze River Basin.展开更多
Charge build-up process in the emitter of a double-barrier resonant tunneling structure is studied by using photoluminescence spectroscopy.Clear evidence is obtained that the charge accumulation in the emitter keeps a...Charge build-up process in the emitter of a double-barrier resonant tunneling structure is studied by using photoluminescence spectroscopy.Clear evidence is obtained that the charge accumulation in the emitter keeps almost constant with bias voltages in the resonant regime,while it increases remarkably with bias voltages beyond resonant regime.The optical results are in good agreement with the electrical measurement.It is demonstrated that the band gap renormalization plays a certain role in the experiment.展开更多
文摘The fluorozirconate glasses ZBLANP( ZrF\-4-BaF\-2-LaF\-3-AlF\-3-NaF-PbF\-2) doped with different Yb\+ 3+ concentration were prepared. The Raman spectra and absorption spectra are measured to substantiate the existence of phonon-assisted emission. After analyzing the normalized absorption spectra of samples with different Yb\+ 3+-doped concentration, we calculated the maximum cooling effect in the 3 wt% Yb\+ 3+-doped sample pumped at 1 012.5 nm. The corresponding cooling capability is about -4.09 ℃/W and the cooling efficiency reaches 1.76%.
基金supported by the Science and Technology Plan Project of Hubei Province,China(2012BLB228)the National Key Research and Development Program of China(2017YFD0301402)+2 种基金the National Natural Science Foundation of China(31701359)the Fundamental Research Funds for the Central Universities,China(2662017JC007)the China Postdoctoral Science Foundation(2017M612477)。
文摘Rice grain yield and quality declines are due to unsuitable temperatures from wide regions and various sowing dates.This study aimed to evaluate the effects of temperature on rice yield and quality at different phenological periods and obtain suitable temperatures for phenological periods in the Yangtze River Basin,China.This study conducted experiments on different sowing dates under different areas in the Yangtze River Basin to observe and compare the differences in rice growth,yield,and quality,controlling for regional varieties.The results showed significant differences in rice growth,yield,and quality among sowing dates and areas,which were related to the average daily temperature during the vegetative period(VT)and the first 20 days of the grain-filling period(GT20).In addition,there was a smaller variation in the average daily temperature in the reproductive period(RT)than in the two phenological periods.Therefore,according to the VT and GT20 thresholds of different yields and qualities,the experimental results were divided into four scenarios(Ⅰ,Ⅱ,Ⅲ,andⅣ)in this study.In Scenario I,high head rice production(rice grain yield multiplied by head rice rate)and rice quality could be obtained.The head rice production of ScenariosⅢandⅣwas lower than that of ScenarioⅠ,by 30.1 and 27.6%,respectively.In Scenario II,the head rice production increased insignificantly while the chalky grain rate and chalkiness were 50.6 and 56.3%higher than those of Scenario I.In conclusion,the Scenario I combination with VT ranges of 22.8-23.9℃and GT20 ranges of 24.2-27.0℃or the combination with VT ranges of 23.9-25.3℃and GT20 ranges of 24.2-24.9℃,which can be obtained by adjusting sowing date and selecting rice varieties with suitable growth periods,is recommended to achieve high levels of rice grain yield and quality in the Yangtze River Basin.
基金Supported by the State Science and Technology Commission,and the National Natural Science Foundation of China.
文摘Charge build-up process in the emitter of a double-barrier resonant tunneling structure is studied by using photoluminescence spectroscopy.Clear evidence is obtained that the charge accumulation in the emitter keeps almost constant with bias voltages in the resonant regime,while it increases remarkably with bias voltages beyond resonant regime.The optical results are in good agreement with the electrical measurement.It is demonstrated that the band gap renormalization plays a certain role in the experiment.
