A molten salt method was developed to prepare porous La1‐xSrxMn0.8Fe0.2O3 （0≤ x ≤ 0.6） micro‐spheres using hierarchical porous δ‐MnO2 microspheres as a template in eutectic NaNO3‐KNO3. X‐ray diffraction patt...A molten salt method was developed to prepare porous La1‐xSrxMn0.8Fe0.2O3 （0≤ x ≤ 0.6） micro‐spheres using hierarchical porous δ‐MnO2 microspheres as a template in eutectic NaNO3‐KNO3. X‐ray diffraction patterns showed that single phase LaMn0.8Fe0.2O3 with good crystallinity was syn‐thesized at 450℃ after 4 h. Transmission electron microscope images exhibited that the LaMn0.8Fe0.2O3 sample obtained at 450？？ after 4 h possessed a porous spherical morphology com‐posed of aggregated nanocrystallites. Field emission scanning electron microscope images indicated that the growth of the porous LaMn0.8Fe0.2O3 microspheres has two stages. SEM pictures showed that a higher calcination temperature than 450？？ had an adverse effect on the formation of a po‐rous spherical structure. The LaMn0.8Fe0.2O3 sample obtained at 450？？ after 4 h displayed a high BET surface area of 55.73 m2/g with a pore size of 9.38 nm. Fourier transform infrared spectra suggested that Sr2＋ions entered the A sites and induced a decrease of the binding energy between Mn and O. The CO conversion with the La1‐xSrxMn0.8Fe0.2O3 （0≤x≤0.6） samples indicated that the La0.4Sr0.6Mn0.8Fe0.2O3 sample had the best catalytic activity and stability. Further analysis by X‐ray photoelectron spectroscopy demonstrated that Sr2＋doping altered the content of Mn4＋ions, oxygen vacancies and adsorbed oxygen species on the surface, which affected the catalytic performance for CO oxidation.展开更多
Catalytic combustion of dimethyl ether （DME） over hexaaluminate catalyst BaNi0.2Mn0.8Al11O19-δ has been investigated. The catalysts were prepared with the sol-gel method and reverse microemulsion method respectivel...Catalytic combustion of dimethyl ether （DME） over hexaaluminate catalyst BaNi0.2Mn0.8Al11O19-δ has been investigated. The catalysts were prepared with the sol-gel method and reverse microemulsion method respectively and characterized by thermogravimetry-differential thermal analysis, X-ray diffraction and transimission electron microscope. It was found that the formation of Mn, Ni modified hexaaluminate was a relatively slow process via two solid state reactions and spinel structure was a transition phase. At the same calcined temperature and time, the catalyst prepared with the reverse microemulsion method could form the hexaaluminate phase more easily than that prepared with the sol-gel method. The catalyst BaNi0.2Mn0.8Al11O19-δ prepared with the reverse micro-emulsion method appeared a plate-like morphology, while it appeared a needle-like morphology when using the sol-gel method. The catalytic activities of catalysts BaNi0.2Mn0.8Al11O19-δ prepared with two different methods for DME combustion were tested. It showed that catalyst prepared with the reverse microemulsion method had better catalytic activity, i.e. T10% of DME had decreased by 45℃, about 90% conversion of diemthyl ether at 380℃.展开更多
Dense membrane with the composition of SrFe0.6Cu0.3Ti0.1O3-δ （SFCTO） was prepared by solid state reaction method. Oxygen permeation flux through this membrane was investigated at operating temperature ranging from ...Dense membrane with the composition of SrFe0.6Cu0.3Ti0.1O3-δ （SFCTO） was prepared by solid state reaction method. Oxygen permeation flux through this membrane was investigated at operating temperature ranging from 750℃ to 950℃ and different oxygen partial pressure. XRD measurements indicated that the compound was able to form single-phased perovskite structure in which part of Fe was replaced by Cu and Ti. The oxygen desorption and the reducibility of SFCTO powder were characterized by thermogravimetric analysis and temperature programmed reduction analysis, respectively. It was found that SFCTO had good structure stability under low oxygen pressure at high temperature. The addition of Ti increased the reduction temperature of Cu and Fe. Performance tests showed that the oxygen permeation flux through a 1.5 mm thick SFCTO membrane was 0.35-0.96 ml·min ^-1·cm^-2 under air/helium oxygen partial pressure gradient with activation energy of 53.2 kJ·mol^-1. The methane conversion of 85%, CO selectivity of 90% and comparatively higher oxygen permeation flux of 5 ml·min^-1·cm^- 2 were achieved at 850℃, when a SFCTO membrane reactor loaded with Ni-Ce/Al2O3 catalyst was applied for the partial oxidation of methane to syngas.展开更多
Objective:The aim of the study was to compare the effects of photodynamic therapy(PDT) with δ-aminolevulinic acid(ALA) for patients with different kinds of skin cancers and pre-cancers.Methods:The present study enrol...Objective:The aim of the study was to compare the effects of photodynamic therapy(PDT) with δ-aminolevulinic acid(ALA) for patients with different kinds of skin cancers and pre-cancers.Methods:The present study enrolled seventyfive cases,which included 17 cases of actinic keratosis(AK),9 cases of Bowen's disease,11 cases of superficial basal cell carcinomas(BCC),23 cases of nodule basal cell carcinomas and 15 cases of squamous cell carcinomas(SCC),and every patient had single lesion.All patients were treated with 20% ALA topically and He-Ne laser weekly for three times,and followed up 1-3 years.Results:After therapy,the rates of complete reaction(CR) were 100% in AK lesions,77.8% in Bowen's diseases,90.9% in superficial BCCs,47.8% in nodule BCCs,and 50.3% in SCCs,which had significant differences among these five kinds of lesions(H = 18.27,P < 0.05).The therapeutic effectiveness of ALA-PDT for AK was superior to that of Bowen's disease(Q = 4.364,P < 0.05),superficial BCC(Q = 5.55,P < 0.01),SCC(Q = 8.94,P < 0.01) and nodule BCC(Q = 17.91,P < 0.01);the effect of Bowen's disease was better than that of SCC(Q = 7.8,P < 0.01),nodule BCC(Q = 13.44,P < 0.01);the effect of superficial BCC was better than that of SCC(Q = 9.73,P < 0.01),nodule BCC(Q = 16.28,P < 0.01),but similar with Bowen's disease(Q = 0.96,P > 0.05);the effect of SCC was better than that of nodule BCC(Q = 17.74,P < 0.01).Conclusion:Our study shows that therapeutic effectiveness of ALA-PDT for AK is best in five diseases,and Bowen's disease and superficial BCC are secondary,while nodule BCC and SCC are at the bottom.展开更多
Objective To use δ-aminolevulinic acid induced photodynamic therapy (ALA-PDT) increasingly in treating skin cancers and other diseases in many countries and to explore the efficacy of ALA-PDT for skin cancers in Chi...Objective To use δ-aminolevulinic acid induced photodynamic therapy (ALA-PDT) increasingly in treating skin cancers and other diseases in many countries and to explore the efficacy of ALA-PDT for skin cancers in China. Methods Eighty-eight patients, including 34 cases of basal cell carcinoma (BCC), 32 cases of squamous cell carcinoma (SCC), two cases of basal-squamous cell carcinoma (BSCC), one case of verrucuous carcinoma, nine cases of Bowen disease, two cases Paget disease of the nipple and eight cases of extramammary Paget disease, were treated by the δ-aminolevulinic acid induced photodynamic therapy first in China from 1997 to 2000. Results All BCC, including 11 cases of superficial lesions and 29 solid lesions, achieved complete reaction (CR) by 1-4 times of the ALA-PDT. Except one patient with adenoid SCC (grade Ⅲ), all SCC (grade Ⅰ and grade Ⅱ) patients achieved complete remission by 3-6 times of ALA-PDT. All Bowen diseases achieved complete reaction by 1-4 times. Although for Paget diseases it could not cure the disease simply by ALA-PDT, it could control the symptoms. The recurrence rates were 11% (4/34) for BCC, and 22% (7/32) for SCC by following up 1-3 years after the therapy. The continuous therapy is still effective. Conclusions ALA-PDT is an effective, non-traumatic treatment for patients with BCC, SCC, Bowen and Paget diseases. It is especially suitable for older and weaker patients or those who are not tolerable to other therapies. It also has a unique advantage for tumors in specific anatomical areas. It is a new alternative modality for skin cancer therapies.展开更多
The denitrifier method is widely used as a novel pretreatment method for the determination of nitrogen and oxygen isotope ratios as it can provide quantitative and high-sensitivity measurements. Nevertheless, the meth...The denitrifier method is widely used as a novel pretreatment method for the determination of nitrogen and oxygen isotope ratios as it can provide quantitative and high-sensitivity measurements. Nevertheless, the method is limited by relatively low measurement accuracy for δ18 O. In this study, we analyzed the factors influencing the accuracy of δ18 O determination, and then systematically investigated the effects of dissolved oxygen concentrations and nitrate sample sizes on estimates of the δ15 N and δ18 O of nitrate reference materials. The δ18 O contraction ratio was used to represent the relationship between the measured difference and true difference between two reference materials. We obtained the following main results:(1) a gas-liquid ratio of 3:10(v/v) in ordinary triangular flasks and a shaking speed of 120 r/min produced an optimal range(1.9 to 2.6 mg/L) in the concentration of dissolved oxygen for accurately determining δ18 O, and(2) the δ18 O contraction ratio decreased as nitrate sample size decreased within a certain range(1.0 to 0.1 μmol). Our results suggested that δ18 O contraction is influenced mainly by dissolved oxygen concentrations in pure culture, and provided a model for improving the accuracy of oxygen isotope analysis.展开更多
基金supported by the National Science Foundation for Young Scientists of China (51202171)~~
文摘A molten salt method was developed to prepare porous La1‐xSrxMn0.8Fe0.2O3 （0≤ x ≤ 0.6） micro‐spheres using hierarchical porous δ‐MnO2 microspheres as a template in eutectic NaNO3‐KNO3. X‐ray diffraction patterns showed that single phase LaMn0.8Fe0.2O3 with good crystallinity was syn‐thesized at 450℃ after 4 h. Transmission electron microscope images exhibited that the LaMn0.8Fe0.2O3 sample obtained at 450？？ after 4 h possessed a porous spherical morphology com‐posed of aggregated nanocrystallites. Field emission scanning electron microscope images indicated that the growth of the porous LaMn0.8Fe0.2O3 microspheres has two stages. SEM pictures showed that a higher calcination temperature than 450？？ had an adverse effect on the formation of a po‐rous spherical structure. The LaMn0.8Fe0.2O3 sample obtained at 450？？ after 4 h displayed a high BET surface area of 55.73 m2/g with a pore size of 9.38 nm. Fourier transform infrared spectra suggested that Sr2＋ions entered the A sites and induced a decrease of the binding energy between Mn and O. The CO conversion with the La1‐xSrxMn0.8Fe0.2O3 （0≤x≤0.6） samples indicated that the La0.4Sr0.6Mn0.8Fe0.2O3 sample had the best catalytic activity and stability. Further analysis by X‐ray photoelectron spectroscopy demonstrated that Sr2＋doping altered the content of Mn4＋ions, oxygen vacancies and adsorbed oxygen species on the surface, which affected the catalytic performance for CO oxidation.
基金Supported by the Project of Science and Technology of Guangdong Province （2004B33401003, 2005B10201053）, the Natural Science Foundation of Guangdong Province （04205301, 06021468）, and the Special Functional Material Foundation of Shenzhen University （0602）.
文摘Catalytic combustion of dimethyl ether （DME） over hexaaluminate catalyst BaNi0.2Mn0.8Al11O19-δ has been investigated. The catalysts were prepared with the sol-gel method and reverse microemulsion method respectively and characterized by thermogravimetry-differential thermal analysis, X-ray diffraction and transimission electron microscope. It was found that the formation of Mn, Ni modified hexaaluminate was a relatively slow process via two solid state reactions and spinel structure was a transition phase. At the same calcined temperature and time, the catalyst prepared with the reverse microemulsion method could form the hexaaluminate phase more easily than that prepared with the sol-gel method. The catalyst BaNi0.2Mn0.8Al11O19-δ prepared with the reverse micro-emulsion method appeared a plate-like morphology, while it appeared a needle-like morphology when using the sol-gel method. The catalytic activities of catalysts BaNi0.2Mn0.8Al11O19-δ prepared with two different methods for DME combustion were tested. It showed that catalyst prepared with the reverse microemulsion method had better catalytic activity, i.e. T10% of DME had decreased by 45℃, about 90% conversion of diemthyl ether at 380℃.
基金Supported by the Natural Science Foundation of Guangdong Province （030514） and the Science and Technology Program of Guangdong Province （2004B33401006）.
文摘Dense membrane with the composition of SrFe0.6Cu0.3Ti0.1O3-δ （SFCTO） was prepared by solid state reaction method. Oxygen permeation flux through this membrane was investigated at operating temperature ranging from 750℃ to 950℃ and different oxygen partial pressure. XRD measurements indicated that the compound was able to form single-phased perovskite structure in which part of Fe was replaced by Cu and Ti. The oxygen desorption and the reducibility of SFCTO powder were characterized by thermogravimetric analysis and temperature programmed reduction analysis, respectively. It was found that SFCTO had good structure stability under low oxygen pressure at high temperature. The addition of Ti increased the reduction temperature of Cu and Fe. Performance tests showed that the oxygen permeation flux through a 1.5 mm thick SFCTO membrane was 0.35-0.96 ml·min ^-1·cm^-2 under air/helium oxygen partial pressure gradient with activation energy of 53.2 kJ·mol^-1. The methane conversion of 85%, CO selectivity of 90% and comparatively higher oxygen permeation flux of 5 ml·min^-1·cm^- 2 were achieved at 850℃, when a SFCTO membrane reactor loaded with Ni-Ce/Al2O3 catalyst was applied for the partial oxidation of methane to syngas.
文摘Objective:The aim of the study was to compare the effects of photodynamic therapy(PDT) with δ-aminolevulinic acid(ALA) for patients with different kinds of skin cancers and pre-cancers.Methods:The present study enrolled seventyfive cases,which included 17 cases of actinic keratosis(AK),9 cases of Bowen's disease,11 cases of superficial basal cell carcinomas(BCC),23 cases of nodule basal cell carcinomas and 15 cases of squamous cell carcinomas(SCC),and every patient had single lesion.All patients were treated with 20% ALA topically and He-Ne laser weekly for three times,and followed up 1-3 years.Results:After therapy,the rates of complete reaction(CR) were 100% in AK lesions,77.8% in Bowen's diseases,90.9% in superficial BCCs,47.8% in nodule BCCs,and 50.3% in SCCs,which had significant differences among these five kinds of lesions(H = 18.27,P < 0.05).The therapeutic effectiveness of ALA-PDT for AK was superior to that of Bowen's disease(Q = 4.364,P < 0.05),superficial BCC(Q = 5.55,P < 0.01),SCC(Q = 8.94,P < 0.01) and nodule BCC(Q = 17.91,P < 0.01);the effect of Bowen's disease was better than that of SCC(Q = 7.8,P < 0.01),nodule BCC(Q = 13.44,P < 0.01);the effect of superficial BCC was better than that of SCC(Q = 9.73,P < 0.01),nodule BCC(Q = 16.28,P < 0.01),but similar with Bowen's disease(Q = 0.96,P > 0.05);the effect of SCC was better than that of nodule BCC(Q = 17.74,P < 0.01).Conclusion:Our study shows that therapeutic effectiveness of ALA-PDT for AK is best in five diseases,and Bowen's disease and superficial BCC are secondary,while nodule BCC and SCC are at the bottom.
文摘Objective To use δ-aminolevulinic acid induced photodynamic therapy (ALA-PDT) increasingly in treating skin cancers and other diseases in many countries and to explore the efficacy of ALA-PDT for skin cancers in China. Methods Eighty-eight patients, including 34 cases of basal cell carcinoma (BCC), 32 cases of squamous cell carcinoma (SCC), two cases of basal-squamous cell carcinoma (BSCC), one case of verrucuous carcinoma, nine cases of Bowen disease, two cases Paget disease of the nipple and eight cases of extramammary Paget disease, were treated by the δ-aminolevulinic acid induced photodynamic therapy first in China from 1997 to 2000. Results All BCC, including 11 cases of superficial lesions and 29 solid lesions, achieved complete reaction (CR) by 1-4 times of the ALA-PDT. Except one patient with adenoid SCC (grade Ⅲ), all SCC (grade Ⅰ and grade Ⅱ) patients achieved complete remission by 3-6 times of ALA-PDT. All Bowen diseases achieved complete reaction by 1-4 times. Although for Paget diseases it could not cure the disease simply by ALA-PDT, it could control the symptoms. The recurrence rates were 11% (4/34) for BCC, and 22% (7/32) for SCC by following up 1-3 years after the therapy. The continuous therapy is still effective. Conclusions ALA-PDT is an effective, non-traumatic treatment for patients with BCC, SCC, Bowen and Paget diseases. It is especially suitable for older and weaker patients or those who are not tolerable to other therapies. It also has a unique advantage for tumors in specific anatomical areas. It is a new alternative modality for skin cancer therapies.
基金Project supported by the National Key R&D Program of China(No.2016YFD0200106)the National Natural Science Foundation of China(No.41571450)
文摘The denitrifier method is widely used as a novel pretreatment method for the determination of nitrogen and oxygen isotope ratios as it can provide quantitative and high-sensitivity measurements. Nevertheless, the method is limited by relatively low measurement accuracy for δ18 O. In this study, we analyzed the factors influencing the accuracy of δ18 O determination, and then systematically investigated the effects of dissolved oxygen concentrations and nitrate sample sizes on estimates of the δ15 N and δ18 O of nitrate reference materials. The δ18 O contraction ratio was used to represent the relationship between the measured difference and true difference between two reference materials. We obtained the following main results:(1) a gas-liquid ratio of 3:10(v/v) in ordinary triangular flasks and a shaking speed of 120 r/min produced an optimal range(1.9 to 2.6 mg/L) in the concentration of dissolved oxygen for accurately determining δ18 O, and(2) the δ18 O contraction ratio decreased as nitrate sample size decreased within a certain range(1.0 to 0.1 μmol). Our results suggested that δ18 O contraction is influenced mainly by dissolved oxygen concentrations in pure culture, and provided a model for improving the accuracy of oxygen isotope analysis.
