Both the band filling effect and Fe/Mo disorder have a close correlation with the physical properties of the double perovskite Ca2FeMoO6. Two series of Ca2FeMoO6and Nd0.3Ca1.7FeMoO6ceramics sintered at(1050℃, 1200℃,...Both the band filling effect and Fe/Mo disorder have a close correlation with the physical properties of the double perovskite Ca2FeMoO6. Two series of Ca2FeMoO6and Nd0.3Ca1.7FeMoO6ceramics sintered at(1050℃, 1200℃, and 1300℃) were specially designed to comparatively investigate the band-filling effect and Fe/Mo disorder on the physical properties of Ca2FeMoO6. The x-ray diffraction indicates that Fe/Mo disorder is sensitive to the sintering temperature. The magnetization behavior is mainly controlled by the Fe/Mo disorder not by the band filling effect, manifested by a close correlation of saturated magnetization(Ms) with the Fe/Mo disorder. Interestingly, magnetoresistance(MR) property of the same composition is dominantly contributed by the grain boundary strength, which can be expressed by the macroscopic resistivity values. However, the band filling effect caused by the Nd-substitution can decrease the spin polarization, and thus suppress the MR performance fundamentally. Contrary to the MR response, the Curie temperature(TC) shows an obvious optimization due to the band filling effect, which increases the carrier density near the Fermi level responsible for the ferromagnetic coupling interaction strengthen. Maybe, our work can provoke further research interests into the correlation of the band-filling effects and Fe/Mo disorder with the physical properties of other Fe/Mo-based double perovskites.展开更多
The work focuses on the utilization of the conventional solid-state sintering procedure to synthesize white phosphors Ca_(2)InTaO_(6):xDy^(3+)(0.02≤x≤0.12).Utilizing X-ray diffraction,the phase structure of samples ...The work focuses on the utilization of the conventional solid-state sintering procedure to synthesize white phosphors Ca_(2)InTaO_(6):xDy^(3+)(0.02≤x≤0.12).Utilizing X-ray diffraction,the phase structure of samples was examined,and the crystal structure was refined using the Rietveld method.A scanning electron microscope was used to analyze the microstructure of sample.First-principles calculations confirm that the indirect bandgap of Ca_(2)InTaO_(6)is 3.786 eV,The luminous properties and energy transfer mechanism of Ca_(2)InTaO_(6):xDy^(3+)were studied using photoluminescence spectroscopy.The^(4)F_(9/2)→^(6)H_(13/2)transition of Dy^(3+)ions is responsible for the greatest emission peak,which was measured at 575 nm.According to research,the lifespan falls as the concentration of Dy^(3+)doping amount rises because of frequent interaction and ene rgy transfer between Dy^(3+)ions.The correlated color temperature of the WLEDs packaged with Ca_(2)InTaO_(6):0.08Dy^(3+)is 4677 K and CIE 1931 chromaticity coordinates are(0.3578,0.3831).Meantime,the phosphor also shows outstanding te mperature stability property,which maintains 83.8%of its initial emission intensity at 450 K(activation energy of 0.1467 eV).The W-LEDs retain their performance for 100 min when powered at 3.4 V voltage and 600 mA current,demonstrating the packed W-LEDs'sustaine d operation at high temperatures.展开更多
Nineteen diterpenoids, including saldigitin A(1) bearing an unprecedented 10-methylated 6/7/6 carbon ring system, two new icetexanes(2, 3), and two new nor-abietanes(5, 6) were characterized from the roots of Salvia d...Nineteen diterpenoids, including saldigitin A(1) bearing an unprecedented 10-methylated 6/7/6 carbon ring system, two new icetexanes(2, 3), and two new nor-abietanes(5, 6) were characterized from the roots of Salvia digitaloides. Their structures were elucidated by the analysis of the spectroscopic data,X-ray crystallography, and TDDFT calculations of ECD spectra. The novel architecture of 1 should be biogenetically derived through the cleavage and re-cyclization of the B/C rings from the normal abietane skeleton. Biologically, 1–5 exhibited noticeable inhibitions on Ca_(v)3.1 low voltage-gated Ca2+channel(LVGCC), with IC50values in the range of 3.43–11.70 μmol/L. They are the first example of diterpenoids with 6/7/6 carbon rings system as Ca_(v)3.1 antagonists.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.U1504107)the Doctoral Scientific Research Foundation(Grant No.qd15214)
文摘Both the band filling effect and Fe/Mo disorder have a close correlation with the physical properties of the double perovskite Ca2FeMoO6. Two series of Ca2FeMoO6and Nd0.3Ca1.7FeMoO6ceramics sintered at(1050℃, 1200℃, and 1300℃) were specially designed to comparatively investigate the band-filling effect and Fe/Mo disorder on the physical properties of Ca2FeMoO6. The x-ray diffraction indicates that Fe/Mo disorder is sensitive to the sintering temperature. The magnetization behavior is mainly controlled by the Fe/Mo disorder not by the band filling effect, manifested by a close correlation of saturated magnetization(Ms) with the Fe/Mo disorder. Interestingly, magnetoresistance(MR) property of the same composition is dominantly contributed by the grain boundary strength, which can be expressed by the macroscopic resistivity values. However, the band filling effect caused by the Nd-substitution can decrease the spin polarization, and thus suppress the MR performance fundamentally. Contrary to the MR response, the Curie temperature(TC) shows an obvious optimization due to the band filling effect, which increases the carrier density near the Fermi level responsible for the ferromagnetic coupling interaction strengthen. Maybe, our work can provoke further research interests into the correlation of the band-filling effects and Fe/Mo disorder with the physical properties of other Fe/Mo-based double perovskites.
基金financially supported by the National Natural Science Foundation of China (Grant No. 51862012)the Natural Science Foundation of Jiangxi Province (Grants No. 20202BAB204008, 20165ABC28010)the Innovation Leadership Program of Ganzhou。
基金Project supported by the Science and Technology Foundation of Guizhou Province(20201Y271)。
文摘The work focuses on the utilization of the conventional solid-state sintering procedure to synthesize white phosphors Ca_(2)InTaO_(6):xDy^(3+)(0.02≤x≤0.12).Utilizing X-ray diffraction,the phase structure of samples was examined,and the crystal structure was refined using the Rietveld method.A scanning electron microscope was used to analyze the microstructure of sample.First-principles calculations confirm that the indirect bandgap of Ca_(2)InTaO_(6)is 3.786 eV,The luminous properties and energy transfer mechanism of Ca_(2)InTaO_(6):xDy^(3+)were studied using photoluminescence spectroscopy.The^(4)F_(9/2)→^(6)H_(13/2)transition of Dy^(3+)ions is responsible for the greatest emission peak,which was measured at 575 nm.According to research,the lifespan falls as the concentration of Dy^(3+)doping amount rises because of frequent interaction and ene rgy transfer between Dy^(3+)ions.The correlated color temperature of the WLEDs packaged with Ca_(2)InTaO_(6):0.08Dy^(3+)is 4677 K and CIE 1931 chromaticity coordinates are(0.3578,0.3831).Meantime,the phosphor also shows outstanding te mperature stability property,which maintains 83.8%of its initial emission intensity at 450 K(activation energy of 0.1467 eV).The W-LEDs retain their performance for 100 min when powered at 3.4 V voltage and 600 mA current,demonstrating the packed W-LEDs'sustaine d operation at high temperatures.
基金financially supported by the National Natural Science Foundation of China (Nos. 32070392 and 32070393)the Second Tibetan Plateau Scientific Expedition and Research(STEP) Program (Nos. 2019QZKK0502-0303 and 2019QZKK0502-0304)+2 种基金Natural Science Foundation of Yunnan Province (Nos.202001AS070040 and 202101AV070010)Yunnan Young&Elite Talents Project (No. YNWR-QNBJ-2020-277)CAS “Light of West China” Program (2021)。
文摘Nineteen diterpenoids, including saldigitin A(1) bearing an unprecedented 10-methylated 6/7/6 carbon ring system, two new icetexanes(2, 3), and two new nor-abietanes(5, 6) were characterized from the roots of Salvia digitaloides. Their structures were elucidated by the analysis of the spectroscopic data,X-ray crystallography, and TDDFT calculations of ECD spectra. The novel architecture of 1 should be biogenetically derived through the cleavage and re-cyclization of the B/C rings from the normal abietane skeleton. Biologically, 1–5 exhibited noticeable inhibitions on Ca_(v)3.1 low voltage-gated Ca2+channel(LVGCC), with IC50values in the range of 3.43–11.70 μmol/L. They are the first example of diterpenoids with 6/7/6 carbon rings system as Ca_(v)3.1 antagonists.
