For the purpose of decomposing the processing gases CF4 from semiconductor manufacturers, ceramic honeycomb regenerative burner system is suggested by using the principle of HTAC. A simulated high temperature air comb...For the purpose of decomposing the processing gases CF4 from semiconductor manufacturers, ceramic honeycomb regenerative burner system is suggested by using the principle of HTAC. A simulated high temperature air combustion furnace has been used to determine the features of HTAC flames and the results of the decomposition of CF4. The preheat air temperature of it is above 900℃. The exhaust gas released into the atmosphere is lower than 150℃. Moreover, the efficiency of recovery of waste heat is higher than 80%, the NOx level in exhaust gas is less than 198 mg/m3 and the distribution of temperature in the furnace is nearly uniform. The factors influencing on heat transfer, temperature profile in chamber and NOX emission were discussed. Also some CF4 can be decomposed in this system.展开更多
A novel white-light emitting single-phase phosphor La_3 Si_6 N_(11):Dy^(3+),exhibiting two emission peaks centering at 475 and 575 nm, was prepared via conventional solid-state reactions. The structure and morphology ...A novel white-light emitting single-phase phosphor La_3 Si_6 N_(11):Dy^(3+),exhibiting two emission peaks centering at 475 and 575 nm, was prepared via conventional solid-state reactions. The structure and morphology of La_3 Si_6 N_(11):Dy^(3+)/Tb^(3+) were investigated by X-ray diffraction(XRD) and scanning electron microscopy(SEM). The emission colors can be tuned from white to yellow-green through increasing the Tb^(3+) concentration in La_3 Si_6 N_(11):Dy^(3+),Tb^(3+), The mechanism of energy transfer(ET) from Dy^(3+) to Tb^(3+) is confirmed according to the excitation,emission spectra and decay lifetimes curve. The temperaturedependent luminescence measurements of La_(2.83)Si_6 N_(11):0.1 Dy^(3+),0.07 Tb^(3+) were also performed, and a good thermal stability is shown, suggesting superior properties for the application as white lightemitting diodes(w-LEDs) phosphor.展开更多
La_(2)Mg_(1-x/2)Zr_(1-x/2)O_(6):xBi^(3+)(x=0.01-0.035,abbreviated as LMZ:Bi^(3+))and La_(2-y)Mg_(0.99)Zr_(0.99)O_(6):0.02Bi^(3+),yEu^(3+)(y=0.1-0.11,abbreviated as LMZ:Bi^(3+),Eu^(3+))double-perovskite phosphors were ...La_(2)Mg_(1-x/2)Zr_(1-x/2)O_(6):xBi^(3+)(x=0.01-0.035,abbreviated as LMZ:Bi^(3+))and La_(2-y)Mg_(0.99)Zr_(0.99)O_(6):0.02Bi^(3+),yEu^(3+)(y=0.1-0.11,abbreviated as LMZ:Bi^(3+),Eu^(3+))double-perovskite phosphors were prepared through high-temperature solid-phase method.The emission spectrum of LMZ:xBi^(3+)(x=0.01-0.035)phosphors excited at 353 nm is asymmetric in the range between 375 and 650 nm,showing strong green light.There are two luminescent centers of[Mg1/Zr2-O_(6)]and[Mg2/Zr1-O_(6)]for Bi^(3+)occupation,which were analyzed through different excitation wavelengths,Gaussian fitting peaks,fluorescence decay curves and Rietveld refinement of powder X-ray diffraction data.Through deep study of the luminescent lattices in the LMZ matrix,the green to blue tunning-emission is observed by different excitation wavelengths.In addition,red emission is obtained by co-doping Bi^(3+)/Eu^(3+),and adjustable emission was investigated by changing the content of Eu^(3+)in the co-doped phosphor formulation,so it is converted from green emission to red emission.The above results demonstrate how to tune emission color by co-doping rare earth ions in the double perovskite phosphor,which is attractive for future applications.展开更多
Efficient electronic coupling is the key to constructing optoelectronic functionalπsystems.Generally,the delocalization ofπelectrons must comply with the framework constructed by covalent bonds(typicallyσbonds),rep...Efficient electronic coupling is the key to constructing optoelectronic functionalπsystems.Generally,the delocalization ofπelectrons must comply with the framework constructed by covalent bonds(typicallyσbonds),representing classic through-bond conjuga-tion.However,through-space conjugation offers an alternative that achieves spatial electron communica-tionwith closely stacked π systems instead of covalent bonds thus enabling multidimensional energy and charge transport.展开更多
文摘For the purpose of decomposing the processing gases CF4 from semiconductor manufacturers, ceramic honeycomb regenerative burner system is suggested by using the principle of HTAC. A simulated high temperature air combustion furnace has been used to determine the features of HTAC flames and the results of the decomposition of CF4. The preheat air temperature of it is above 900℃. The exhaust gas released into the atmosphere is lower than 150℃. Moreover, the efficiency of recovery of waste heat is higher than 80%, the NOx level in exhaust gas is less than 198 mg/m3 and the distribution of temperature in the furnace is nearly uniform. The factors influencing on heat transfer, temperature profile in chamber and NOX emission were discussed. Also some CF4 can be decomposed in this system.
基金supported by the National Key Research and Development Plan(2017YFB0404300,2017YFB0404301)
文摘A novel white-light emitting single-phase phosphor La_3 Si_6 N_(11):Dy^(3+),exhibiting two emission peaks centering at 475 and 575 nm, was prepared via conventional solid-state reactions. The structure and morphology of La_3 Si_6 N_(11):Dy^(3+)/Tb^(3+) were investigated by X-ray diffraction(XRD) and scanning electron microscopy(SEM). The emission colors can be tuned from white to yellow-green through increasing the Tb^(3+) concentration in La_3 Si_6 N_(11):Dy^(3+),Tb^(3+), The mechanism of energy transfer(ET) from Dy^(3+) to Tb^(3+) is confirmed according to the excitation,emission spectra and decay lifetimes curve. The temperaturedependent luminescence measurements of La_(2.83)Si_6 N_(11):0.1 Dy^(3+),0.07 Tb^(3+) were also performed, and a good thermal stability is shown, suggesting superior properties for the application as white lightemitting diodes(w-LEDs) phosphor.
基金Project supported by the National Natural Science Foundation of China(51672063,52161145401)the Key Platform Program of Department of Education of Guangdong Province,China(2021ZDZX1003)。
文摘La_(2)Mg_(1-x/2)Zr_(1-x/2)O_(6):xBi^(3+)(x=0.01-0.035,abbreviated as LMZ:Bi^(3+))and La_(2-y)Mg_(0.99)Zr_(0.99)O_(6):0.02Bi^(3+),yEu^(3+)(y=0.1-0.11,abbreviated as LMZ:Bi^(3+),Eu^(3+))double-perovskite phosphors were prepared through high-temperature solid-phase method.The emission spectrum of LMZ:xBi^(3+)(x=0.01-0.035)phosphors excited at 353 nm is asymmetric in the range between 375 and 650 nm,showing strong green light.There are two luminescent centers of[Mg1/Zr2-O_(6)]and[Mg2/Zr1-O_(6)]for Bi^(3+)occupation,which were analyzed through different excitation wavelengths,Gaussian fitting peaks,fluorescence decay curves and Rietveld refinement of powder X-ray diffraction data.Through deep study of the luminescent lattices in the LMZ matrix,the green to blue tunning-emission is observed by different excitation wavelengths.In addition,red emission is obtained by co-doping Bi^(3+)/Eu^(3+),and adjustable emission was investigated by changing the content of Eu^(3+)in the co-doped phosphor formulation,so it is converted from green emission to red emission.The above results demonstrate how to tune emission color by co-doping rare earth ions in the double perovskite phosphor,which is attractive for future applications.
基金This work was financially supported by the National Natural Science Foundation of China(21788102 and 21673082)the National Basic Research Program of Chi-na(973 Program,2015CB655004)founded by MOST+2 种基金the Guangdong Natural Science Funds for Distinguished Young Scholar(2014A030306035)the Natural Science Foundation of Guangdong Province(2016A030312002)the Innovation and Technology Commission of Hong Kong(ITC-CNERC14SC01).
文摘Efficient electronic coupling is the key to constructing optoelectronic functionalπsystems.Generally,the delocalization ofπelectrons must comply with the framework constructed by covalent bonds(typicallyσbonds),representing classic through-bond conjuga-tion.However,through-space conjugation offers an alternative that achieves spatial electron communica-tionwith closely stacked π systems instead of covalent bonds thus enabling multidimensional energy and charge transport.
