This paper presents a novel approach based on differential evolution for short-term combined economic emission hydrothermal scheduling, which is formulated as a bi-objective problem: 1) minimizing fuel cost and 2) min...This paper presents a novel approach based on differential evolution for short-term combined economic emission hydrothermal scheduling, which is formulated as a bi-objective problem: 1) minimizing fuel cost and 2) minimizing emission cost. A penalty factor approach is employed to convert the bi-objective problem into a single objective one. In the proposed approach, heuristic rules are proposed to handle water dynamic balance constraints and heuristic strategies based on priority list are employed to repair active power balance constraints violations. A feasibility-based selection technique is also devised to handle the reservoir storage volumes constraints. The feasibility and effectiveness of the proposed approach are demonstrated and the test results are compared with those of other methods reported in the literature. Numerical experiments show that the proposed method can obtain better-quality solutions with higher precision than any other optimization methods. Hence, the proposed method can well be extended for solving the large-scale hydrothermal sched-uling.展开更多
The preparation of TiO_2 film has been an important research area.In our work,we obtained the TiO_2 film by hydrothermal treating the amorphous film prepared by sol-gel method or the hydrolysis of titanium alkoxide.Th...The preparation of TiO_2 film has been an important research area.In our work,we obtained the TiO_2 film by hydrothermal treating the amorphous film prepared by sol-gel method or the hydrolysis of titanium alkoxide.The influence of temperature and duration time on the film properties was investigated.The photo degradation of methyl orange in aqueous solution of the film was studied.The films were characterized by XRD and Uv-Vis spectroscope.展开更多
A simple and rapid process for synthesizing lead zirconate titanate,Pb（Zr0.52Ti0.48）O3（PZT）,ferroclectric powders was developed.This process,combining the sol-gel and combustion process.offers several advantages o...A simple and rapid process for synthesizing lead zirconate titanate,Pb（Zr0.52Ti0.48）O3（PZT）,ferroclectric powders was developed.This process,combining the sol-gel and combustion process.offers several advantages over conventional methods.including rapid solution synthesis,use of commercially available materials lower synthesis temperature and ease of obtaining ultrafine powders.The precursor solution for synthesizing powders was prepared from lead nitrate.zireonium nitrate.titanium oxynitrate,citric acid and deionized water.The precarsor was investigated by DSC-TG,and the PZT powders were investigated by powder-XRD,IR spectra and TEM.XRD analysis shous that the powders possess a single phase perovskite type structure,no pyrochlore phase exists.and TEM image shows that the grain size of the powders is about 40nm.展开更多
Hydrothermal and sol-gel synthesis methods have been used to prepare nano-particulate hydroxyapatite (HA) powders for detailed characterisation. Bulk elemental analysis data are compared from X-ray diffraction, X-ray ...Hydrothermal and sol-gel synthesis methods have been used to prepare nano-particulate hydroxyapatite (HA) powders for detailed characterisation. Bulk elemental analysis data are compared from X-ray diffraction, X-ray fluorescence and Fourier transform infrared spectroscopy. These show the presence of secondary phases in the sol-gel powders which can be attributed to evaporative loss of precursor phosphite phases during specimen preparation and breakdown of the primary HA phase during calcination. Only the primary HA phase is detected in the hydrothermally prepared powder. In addition, Ca/P ratios of each powder are determined at the particle level using transmission electron microscopy with energy dispersive X-ray spectroscopy (TEM-EDX), having first established a threshold electron fluence below which significant electron-beam-induced alteration of the composition of HA does not occur. The TEM-EDX results show a greater compositional variability of particles from the sol-gel preparation route compared to the hydrothermal route. Overall it is the combination of the analysis techniques that shows the hydrothermal synthesis route produces near- stoichiometric, single phase, hydroxyapatite.展开更多
Eu2+, Dy3+-doped SrAl2O4 was prepared by a hydrothermal reaction through the process of calcination at lower temperature. The physicochemical properties of the SrAl2O4: Eu2+, Dy3+ phosphor were characterized and compa...Eu2+, Dy3+-doped SrAl2O4 was prepared by a hydrothermal reaction through the process of calcination at lower temperature. The physicochemical properties of the SrAl2O4: Eu2+, Dy3+ phosphor were characterized and compared to those of the SrAl2O4: Eu2+, Dy3+ prepared by sol-gel method. The photocatalytic properties of the SrAl2O4: Eu2+, Dy3+ were evaluated in photocatalytic water decomposition for hydrogen production. The SrAl2O4: Eu2+, Dy3+ prepared by hydrothermal reaction exhibited excellent phosphor properties which were similar with that prepared by sol-gel method. Its photocatalytic activity for hydrogen evolution was higher than that of TiO2 photocatalyst.展开更多
A new blue photoluminescent material, a mixed tin and manganese oxide xerogel, is prepared via sol-hydrothermalgel process assisted by citric acid. The composition xerogel exhibits strong blue emission at room tempera...A new blue photoluminescent material, a mixed tin and manganese oxide xerogel, is prepared via sol-hydrothermalgel process assisted by citric acid. The composition xerogel exhibits strong blue emission at room temperature, with an emission maximum at 434 nm under short （234 nm） or long-wavelength （343 nm） ultraviolet excitation. The photoluminescent excitation spectrum of the mixed tin and manganese oxide xerogel, monitored at an intensity maximum wavelength of 434 nm of the emission, consists of two excitation peaks at 234 nm and 343 am. With heat treatment temperature increasing from 110 ℃ to 200 ℃, the blue emission intensity increases remarkably, whereas it is almost completely quenched after being treated at 300 ℃. The carbon impurities in the mixed tin and manganese oxide xerogel, confirmed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, should be responsible for the bright blue photoluminescence.展开更多
Tungsten （VI） oxide （WO3） nanomaterials were synthesized by a sol-gel method using WC16 and C2HsOH as precursors followed by calcination or hydrothermal treatment. X-Ray diffraction （XRD）, scanning electron micr...Tungsten （VI） oxide （WO3） nanomaterials were synthesized by a sol-gel method using WC16 and C2HsOH as precursors followed by calcination or hydrothermal treatment. X-Ray diffraction （XRD）, scanning electron microscopy （SEM） and high resolution transmission electron microscopy （HRTEM） equipped with energy dispersive X-ray spectroscopy （EDX） were used to characterize the structure and morphology of the materials. There were significant differences between the WO3 materials that were calcinated and those that were subjected to a hydrothermal process. The XRD results revealed that calcination temperatures of 300℃and 400℃ gave hexagonal structures and temperatures of 500℃ and 600℃ gave monoclinic structures. The SEM images showed that an increase in calcination temperature led to a decrease in the WO3 powder particle size. The TEM analysis showed that several nanoparticles agglomerated to form bigger clusters. The hydrothermal process produced hexagonal structures for holding times of 12, 16, and 20 h and monoclinic structures for a holding time of 24 h. The SEM results showed transparent rectangular panicles which according to the TEM results originated from the aggregation of several nanotubes.展开更多
文摘This paper presents a novel approach based on differential evolution for short-term combined economic emission hydrothermal scheduling, which is formulated as a bi-objective problem: 1) minimizing fuel cost and 2) minimizing emission cost. A penalty factor approach is employed to convert the bi-objective problem into a single objective one. In the proposed approach, heuristic rules are proposed to handle water dynamic balance constraints and heuristic strategies based on priority list are employed to repair active power balance constraints violations. A feasibility-based selection technique is also devised to handle the reservoir storage volumes constraints. The feasibility and effectiveness of the proposed approach are demonstrated and the test results are compared with those of other methods reported in the literature. Numerical experiments show that the proposed method can obtain better-quality solutions with higher precision than any other optimization methods. Hence, the proposed method can well be extended for solving the large-scale hydrothermal sched-uling.
文摘The preparation of TiO_2 film has been an important research area.In our work,we obtained the TiO_2 film by hydrothermal treating the amorphous film prepared by sol-gel method or the hydrolysis of titanium alkoxide.The influence of temperature and duration time on the film properties was investigated.The photo degradation of methyl orange in aqueous solution of the film was studied.The films were characterized by XRD and Uv-Vis spectroscope.
文摘A simple and rapid process for synthesizing lead zirconate titanate,Pb（Zr0.52Ti0.48）O3（PZT）,ferroclectric powders was developed.This process,combining the sol-gel and combustion process.offers several advantages over conventional methods.including rapid solution synthesis,use of commercially available materials lower synthesis temperature and ease of obtaining ultrafine powders.The precursor solution for synthesizing powders was prepared from lead nitrate.zireonium nitrate.titanium oxynitrate,citric acid and deionized water.The precarsor was investigated by DSC-TG,and the PZT powders were investigated by powder-XRD,IR spectra and TEM.XRD analysis shous that the powders possess a single phase perovskite type structure,no pyrochlore phase exists.and TEM image shows that the grain size of the powders is about 40nm.
文摘Hydrothermal and sol-gel synthesis methods have been used to prepare nano-particulate hydroxyapatite (HA) powders for detailed characterisation. Bulk elemental analysis data are compared from X-ray diffraction, X-ray fluorescence and Fourier transform infrared spectroscopy. These show the presence of secondary phases in the sol-gel powders which can be attributed to evaporative loss of precursor phosphite phases during specimen preparation and breakdown of the primary HA phase during calcination. Only the primary HA phase is detected in the hydrothermally prepared powder. In addition, Ca/P ratios of each powder are determined at the particle level using transmission electron microscopy with energy dispersive X-ray spectroscopy (TEM-EDX), having first established a threshold electron fluence below which significant electron-beam-induced alteration of the composition of HA does not occur. The TEM-EDX results show a greater compositional variability of particles from the sol-gel preparation route compared to the hydrothermal route. Overall it is the combination of the analysis techniques that shows the hydrothermal synthesis route produces near- stoichiometric, single phase, hydroxyapatite.
文摘Eu2+, Dy3+-doped SrAl2O4 was prepared by a hydrothermal reaction through the process of calcination at lower temperature. The physicochemical properties of the SrAl2O4: Eu2+, Dy3+ phosphor were characterized and compared to those of the SrAl2O4: Eu2+, Dy3+ prepared by sol-gel method. The photocatalytic properties of the SrAl2O4: Eu2+, Dy3+ were evaluated in photocatalytic water decomposition for hydrogen production. The SrAl2O4: Eu2+, Dy3+ prepared by hydrothermal reaction exhibited excellent phosphor properties which were similar with that prepared by sol-gel method. Its photocatalytic activity for hydrogen evolution was higher than that of TiO2 photocatalyst.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10904008)Joint Funds of the National Natural Science Foundation of China (Grant No. 11076008)the Young Scientists Foundation of Sichuan Province of China(Grant No. 2010JQ0006)
文摘A new blue photoluminescent material, a mixed tin and manganese oxide xerogel, is prepared via sol-hydrothermalgel process assisted by citric acid. The composition xerogel exhibits strong blue emission at room temperature, with an emission maximum at 434 nm under short （234 nm） or long-wavelength （343 nm） ultraviolet excitation. The photoluminescent excitation spectrum of the mixed tin and manganese oxide xerogel, monitored at an intensity maximum wavelength of 434 nm of the emission, consists of two excitation peaks at 234 nm and 343 am. With heat treatment temperature increasing from 110 ℃ to 200 ℃, the blue emission intensity increases remarkably, whereas it is almost completely quenched after being treated at 300 ℃. The carbon impurities in the mixed tin and manganese oxide xerogel, confirmed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, should be responsible for the bright blue photoluminescence.
文摘Tungsten （VI） oxide （WO3） nanomaterials were synthesized by a sol-gel method using WC16 and C2HsOH as precursors followed by calcination or hydrothermal treatment. X-Ray diffraction （XRD）, scanning electron microscopy （SEM） and high resolution transmission electron microscopy （HRTEM） equipped with energy dispersive X-ray spectroscopy （EDX） were used to characterize the structure and morphology of the materials. There were significant differences between the WO3 materials that were calcinated and those that were subjected to a hydrothermal process. The XRD results revealed that calcination temperatures of 300℃and 400℃ gave hexagonal structures and temperatures of 500℃ and 600℃ gave monoclinic structures. The SEM images showed that an increase in calcination temperature led to a decrease in the WO3 powder particle size. The TEM analysis showed that several nanoparticles agglomerated to form bigger clusters. The hydrothermal process produced hexagonal structures for holding times of 12, 16, and 20 h and monoclinic structures for a holding time of 24 h. The SEM results showed transparent rectangular panicles which according to the TEM results originated from the aggregation of several nanotubes.
