Un-doped and ZnAl_(x)O_(1.5x+1):0.1 mol%Tb^(3+)(ZAOT)nano-powders were synthesized via citrate sol-gel method.The AIx moles were varied in the range of 0.25≤x≤5.0.The X-ray powder diffraction(XRD)data reveal that fo...Un-doped and ZnAl_(x)O_(1.5x+1):0.1 mol%Tb^(3+)(ZAOT)nano-powders were synthesized via citrate sol-gel method.The AIx moles were varied in the range of 0.25≤x≤5.0.The X-ray powder diffraction(XRD)data reveal that for x<1.5,the prepared samples crystal structure consists of mixed phases of the cubic ZnAl_(2)O_(4) and hexagonal ZnO phases,while for x>1.5 the structure consists of single phase of cubic ZnAl_(2)O_(4).The Raman and Fourier-trans form infrared(FTIR)vibrational spectroscopy show the presence of vibrations emanating ZnAl_(2)O_(4) spinel.Scanning electron microscopy(SEM)and transmission electron microscopy(TEM)show the presence of irregular sphere at x>2.0 attributed to ZnAl_(2)O_(4).The photoluminescence(PL)spectroscopy reveals emissions from both the host and Tb^(3+)transitions.Emissions from Tb^(3+)are observed at 382,414,439,458 nm and 489,545,585,621 nm,which were attributed to the^(5)D_(3)→^(7)F_(6,5,4,2) and ^(5^)D_(4)→^(7)F_(6,5,4,3),respectively.The results confirm that the Tb^(3+)occupation site depends on the Alx moles.The International Commission on Illumination(CIE)colour chromaticity shows that the emission colour can be tuned from blue to green by varying the AIx moles.展开更多
The energy transfer and upconversion of Er 3+ /Yb 3+ co-doped TeO2-TiO2-K2O glasses upon excitation with 976nm lasers diode were studied. The tellurite glasses were prepared by conventional melting methods. Their opti...The energy transfer and upconversion of Er 3+ /Yb 3+ co-doped TeO2-TiO2-K2O glasses upon excitation with 976nm lasers diode were studied. The tellurite glasses were prepared by conventional melting methods. Their optical properties and sensitization upconversion spectra were performed. The dependence of green upconversion luminescence intensity on the mole ratio of Yb 3+ to Er 3+ and Er 3+ concentration were discussed in detail. When the mole ratio of Yb 3+ to Er 3+ is 25/1 and Er 3+ concentration is 0.1% （mole fraction）, or when the mole ratio of Yb 3+ to Er 3+ is 10/1 and Er 3+ concentration is 0.15%, the optimal upconversion luminescence intensity is obtained. The obtained glasses can be one of the potential candidates for lasers-diode pumping microchip solid-state lasers.展开更多
The ternary solid complex was synthesized with sodium diethyldithiocarbamate (NaEt_2dtc), 1,10-phenanthroline (phen) and low hydrated dysprosium chloride in absolute ethanol by improved method of reference. The title ...The ternary solid complex was synthesized with sodium diethyldithiocarbamate (NaEt_2dtc), 1,10-phenanthroline (phen) and low hydrated dysprosium chloride in absolute ethanol by improved method of reference. The title complex was identified as the general formula of Dy(Et_2dtc)_3(phen) by chemical and elemental analyses. IR spectrum of the complex shows that the Dy^(3+) coordinated with six sulfur atoms of three NaEt_2dtc and two nitrogen atoms of phen. It is assumed that the coordination number of Dy^(3+) is eight.The enthalpy change of liquid-phase reaction of formation, Δ_rH~θ_m(l), is determined as (-19.091±0.015) kJ·mol^(-1) at 298.15 K by a microcalorimeter, and the enthalpy change of the solid-phase reaction of formation, Δ_rH~θ_m(s), is calculated as (139.641±0.482) kJ·mol^(-1) on the basis of a thermochemical cycle. The thermodynamic of reaction of formation was studied by changing the temperature of liquid-phase reaction. The constant-volume combustion energy of the complex, Δ_cU, is determined as (-16730.21±9.25) kJ·mol^(-1) by a precise rotating-bomb calorimeter at 298.15 K. Its standard enthalpies of combustion, Δ_cH~θ_m, and standard enthalpies of formation, Δ_fH~θ_m, are calculated as (-16749.42±9.25) kJ·mol^(-1) and (-2019.68±10.19) kJ·mol^(-1), respectively.展开更多
Automatic berthing guidance is an important aspect of automated ship technology to obtain the ship-shore position relationship.The current mainstream measurement methods for ship-shore position relationships are based...Automatic berthing guidance is an important aspect of automated ship technology to obtain the ship-shore position relationship.The current mainstream measurement methods for ship-shore position relationships are based on radar,multisensor fusion,and visual detection technologies.This paper proposes an automated ship berthing guidance method based on three-dimensional(3D)target measurement and compares it with a single-target recognition method using a binocular camera.An improved deep object pose estimation(DOPE)network is used in this method to predict the pixel coordinates of the two-dimensional(2D)keypoints of the shore target in the image.The pixel coordinates are then converted into 3D coordinates through the camera imaging principle,and an algorithm for calculating the relationship between the ship and the shore is proposed.Experiments were conducted on the improved DOPE network and the actual ship guidance performance to verify the effectiveness of the method.Results show that the proposed method with a monocular camera has high stability and accuracy and can meet the requirements of automatic berthing.展开更多
Analysis of the Si and AI phases in coal gangue fuel and its ash is important for use of coal gangue ashes. A comprehensive study by theoretical and experimental analyses with differential thermal analysis, X-ray diff...Analysis of the Si and AI phases in coal gangue fuel and its ash is important for use of coal gangue ashes. A comprehensive study by theoretical and experimental analyses with differential thermal analysis, X-ray diffraction and Infrared Spectroscopy has been made in the present article to explore the diagram of the Si and Al phases in coal gangue fuel and its ashes. It is found that kaolinite and quartz are the main phases in coal gangue fuel. The ratio of moles A1203 to SiO2 （i.e., Al2O3 （mole） / SiO2 （mole）） is usually no more than 0.5 in most coal gangue fuel and its ashes. The kaolinit at about 984℃ releases a large quantity of SiO2, which makes calcine coal gangue more active than coal gangue itself. The relationship between the ratio A1203 （mole）]SiO2（mole）and the components of coal gangue ash is analyzed, resulting in a formula to calculate the quantity of each phase. Applying the formula to the testing samples from an electric plant in north China supports the above conclusions.展开更多
Thermo-physical properties of Al-Mg alloys in molten state at 1073 K have been studied using thermodynamic modeling. Thermodynamic properties, such as free energy of mixing, heat of mixing, entropy of mixing, activiti...Thermo-physical properties of Al-Mg alloys in molten state at 1073 K have been studied using thermodynamic modeling. Thermodynamic properties, such as free energy of mixing, heat of mixing, entropy of mixing, activities and structural properties, such as concentration fluctuation in long wavelength limit, Warren-Cowely short range order parameter have been studied at 1073 K, 1173 K, 1273 K and 1373 K on the basis of regular associated solution model. The surface properties such as surface concentrations and surface tension of the liquid alloys have been studied by using Butler’s model. A consistent set of model parameters have also been obtained by using optimization procedure based on statistical thermodynamics. Our analysis reveals that Al-Mg alloy is moderately interacting and it shows ordering nature at 1073 K. The nature of the alloys changes from ordering to segregating as the temperature increases.展开更多
基金Project supported by the South African National Research Foundation(NRF)Thuthuka programme(UID 99266,113947)NRF Incentive Funding for Rated Researchers(IPRR)(114924)NRF Black Academics Advancement Programme(BAAP)(138233)。
文摘Un-doped and ZnAl_(x)O_(1.5x+1):0.1 mol%Tb^(3+)(ZAOT)nano-powders were synthesized via citrate sol-gel method.The AIx moles were varied in the range of 0.25≤x≤5.0.The X-ray powder diffraction(XRD)data reveal that for x<1.5,the prepared samples crystal structure consists of mixed phases of the cubic ZnAl_(2)O_(4) and hexagonal ZnO phases,while for x>1.5 the structure consists of single phase of cubic ZnAl_(2)O_(4).The Raman and Fourier-trans form infrared(FTIR)vibrational spectroscopy show the presence of vibrations emanating ZnAl_(2)O_(4) spinel.Scanning electron microscopy(SEM)and transmission electron microscopy(TEM)show the presence of irregular sphere at x>2.0 attributed to ZnAl_(2)O_(4).The photoluminescence(PL)spectroscopy reveals emissions from both the host and Tb^(3+)transitions.Emissions from Tb^(3+)are observed at 382,414,439,458 nm and 489,545,585,621 nm,which were attributed to the^(5)D_(3)→^(7)F_(6,5,4,2) and ^(5^)D_(4)→^(7)F_(6,5,4,3),respectively.The results confirm that the Tb^(3+)occupation site depends on the Alx moles.The International Commission on Illumination(CIE)colour chromaticity shows that the emission colour can be tuned from blue to green by varying the AIx moles.
基金Projects(2004Z2-D0131 and 2004A10602002) supported by the Science and Technology Programof Guangzhou , Guang-dong Province project(60307004 and 50472053) supported by the National Natural Science Foundation of China project(04200036) sup-ported by the Natural Foundation of Guangdong Province
文摘The energy transfer and upconversion of Er 3+ /Yb 3+ co-doped TeO2-TiO2-K2O glasses upon excitation with 976nm lasers diode were studied. The tellurite glasses were prepared by conventional melting methods. Their optical properties and sensitization upconversion spectra were performed. The dependence of green upconversion luminescence intensity on the mole ratio of Yb 3+ to Er 3+ and Er 3+ concentration were discussed in detail. When the mole ratio of Yb 3+ to Er 3+ is 25/1 and Er 3+ concentration is 0.1% （mole fraction）, or when the mole ratio of Yb 3+ to Er 3+ is 10/1 and Er 3+ concentration is 0.15%, the optimal upconversion luminescence intensity is obtained. The obtained glasses can be one of the potential candidates for lasers-diode pumping microchip solid-state lasers.
文摘The ternary solid complex was synthesized with sodium diethyldithiocarbamate (NaEt_2dtc), 1,10-phenanthroline (phen) and low hydrated dysprosium chloride in absolute ethanol by improved method of reference. The title complex was identified as the general formula of Dy(Et_2dtc)_3(phen) by chemical and elemental analyses. IR spectrum of the complex shows that the Dy^(3+) coordinated with six sulfur atoms of three NaEt_2dtc and two nitrogen atoms of phen. It is assumed that the coordination number of Dy^(3+) is eight.The enthalpy change of liquid-phase reaction of formation, Δ_rH~θ_m(l), is determined as (-19.091±0.015) kJ·mol^(-1) at 298.15 K by a microcalorimeter, and the enthalpy change of the solid-phase reaction of formation, Δ_rH~θ_m(s), is calculated as (139.641±0.482) kJ·mol^(-1) on the basis of a thermochemical cycle. The thermodynamic of reaction of formation was studied by changing the temperature of liquid-phase reaction. The constant-volume combustion energy of the complex, Δ_cU, is determined as (-16730.21±9.25) kJ·mol^(-1) by a precise rotating-bomb calorimeter at 298.15 K. Its standard enthalpies of combustion, Δ_cH~θ_m, and standard enthalpies of formation, Δ_fH~θ_m, are calculated as (-16749.42±9.25) kJ·mol^(-1) and (-2019.68±10.19) kJ·mol^(-1), respectively.
基金The EDD of China(No.80912020104)the Science and Technology Commission of Shanghai Municipality(Grant No.22ZR1427700 and No.23692106900)。
文摘Automatic berthing guidance is an important aspect of automated ship technology to obtain the ship-shore position relationship.The current mainstream measurement methods for ship-shore position relationships are based on radar,multisensor fusion,and visual detection technologies.This paper proposes an automated ship berthing guidance method based on three-dimensional(3D)target measurement and compares it with a single-target recognition method using a binocular camera.An improved deep object pose estimation(DOPE)network is used in this method to predict the pixel coordinates of the two-dimensional(2D)keypoints of the shore target in the image.The pixel coordinates are then converted into 3D coordinates through the camera imaging principle,and an algorithm for calculating the relationship between the ship and the shore is proposed.Experiments were conducted on the improved DOPE network and the actual ship guidance performance to verify the effectiveness of the method.Results show that the proposed method with a monocular camera has high stability and accuracy and can meet the requirements of automatic berthing.
基金part of a key project carried out during 2006-2008supported by the National Postdoct Foundation of China (No.20070420417)the Project of the Yunxi Corporation (2007-13A)
文摘Analysis of the Si and AI phases in coal gangue fuel and its ash is important for use of coal gangue ashes. A comprehensive study by theoretical and experimental analyses with differential thermal analysis, X-ray diffraction and Infrared Spectroscopy has been made in the present article to explore the diagram of the Si and Al phases in coal gangue fuel and its ashes. It is found that kaolinite and quartz are the main phases in coal gangue fuel. The ratio of moles A1203 to SiO2 （i.e., Al2O3 （mole） / SiO2 （mole）） is usually no more than 0.5 in most coal gangue fuel and its ashes. The kaolinit at about 984℃ releases a large quantity of SiO2, which makes calcine coal gangue more active than coal gangue itself. The relationship between the ratio A1203 （mole）]SiO2（mole）and the components of coal gangue ash is analyzed, resulting in a formula to calculate the quantity of each phase. Applying the formula to the testing samples from an electric plant in north China supports the above conclusions.
文摘Thermo-physical properties of Al-Mg alloys in molten state at 1073 K have been studied using thermodynamic modeling. Thermodynamic properties, such as free energy of mixing, heat of mixing, entropy of mixing, activities and structural properties, such as concentration fluctuation in long wavelength limit, Warren-Cowely short range order parameter have been studied at 1073 K, 1173 K, 1273 K and 1373 K on the basis of regular associated solution model. The surface properties such as surface concentrations and surface tension of the liquid alloys have been studied by using Butler’s model. A consistent set of model parameters have also been obtained by using optimization procedure based on statistical thermodynamics. Our analysis reveals that Al-Mg alloy is moderately interacting and it shows ordering nature at 1073 K. The nature of the alloys changes from ordering to segregating as the temperature increases.
