BACKGROUND Excessive oxidative stress plays a key role in the development of diabetic complications,including impaired ulcer healing.Previous studies have shown that fish scale ointment can promote wound healing.AIM T...BACKGROUND Excessive oxidative stress plays a key role in the development of diabetic complications,including impaired ulcer healing.Previous studies have shown that fish scale ointment can promote wound healing.AIM To preliminarily investigate the effect of fish scale ointment on wound healing in a diabetic foot ulcer(DFU)rat model by examining its regulation of the nuclear factor E2-related factor 2(Nrf2)pathway and induction of ferroptosis.METHODS Fish scale ointment(collagen product)was prepared from 500 g of silver carp scales.A diabetic rat model was induced by high-fat and high-sugar feeding combined with intraperitoneal streptozotocin injections.For the DFU rat model,ulcer wounds were created by removing dorsal foot hair and cutting the skin to the fascia.The diabetic rats were randomized into five groups:Model,fish scale collagen(FSC),control+liproxstatin-1(Lip-1),model+Lip-1,and FSC+Lip-1.In each group,treatments were administered once daily by topical application and intraperitoneal injection for 14 days.Wound healing was evaluated on days 7 and 14 after treatment.Hematoxylin and eosin staining was used to assess wound injury and capillary formation.Basic fibroblast growth factor(bFGF)and CD31 levels in wound tissue were measured by immunohistochemistry.Additionally,malondialdehyde(MDA),glutathione(GSH),ferroptosis-associated genes,and iron ion concentrations were quantified using assay kits.Protein levels of Nrf2,heme oxygenase-1(HO-1),and glutathione peroxidase 4(GPX4)were determined using Western blotting.RESULTS Compared with the control group,the model group showed slower wound healing,reduced angiogenesis,decreased bFGF and CD31 levels,increased iron ion concentration and MDA levels,reduced GSH levels,and decreased Nrf2,HO-1,and GPX4 protein expression(all P<0.05).The FSC,model+Lip-1,and FSC+Lip-1 groups showed increased wound healing and angiogenesis,elevated bFGF and CD31 expression,lowered iron ion concentration and MDA levels,increased GSH levels,and enhanced Nrf2,HO-1,and GPX4 protein levels compared with the model group(P<0.05).Improvements were more pronounced in the FSC+Lip-1 group compared with the FSC group(P<0.05).CONCLUSION Fish scale ointment promotes angiogenesis and wound healing in DFU rat models by inhibiting ferroptosis,possibly through the activation of the Nrf2 pathway.展开更多
To elucidate the effects of Cl^(-)and Ca^(2+) on the corrosion and scale formation of 3Cr steel in CO_(2) floodingproduced fluid,corrosion weight loss experiments,and titration experiments were conducted.The resulting...To elucidate the effects of Cl^(-)and Ca^(2+) on the corrosion and scale formation of 3Cr steel in CO_(2) floodingproduced fluid,corrosion weight loss experiments,and titration experiments were conducted.The resulting products were characterized using scanning electron microscopy(SEM),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS).This study examined the corrosion and scaling behavior of 3Cr steel under the influence of Cl^(-)and Ca^(2+).The results indicate that both Cl^(-)and Ca^(2+)promote the corro sion of 3Cr steel.Notably,Cl^(-)diminishes the promoting effect of Ca^(2+)on corro sion and inhibits scaling,revealing a mutual enhancement between corrosion and scaling.The mechanisms of localized corrosion under varying concentrations of Cl^(-)and Ca^(2+)differ;under-scale corrosion occurs in environments with 5000 mg·L^(-1) Cl^(-),while Cl^(-)induced corrosion is observed in 20000 mg·L^(-1) Cl^(-)environments.This study highlights that under the synergistic effects of Cl^(-),Ca^(2+),and scaling processes,the protective product film dissolves,thereby influencing both corrosion and scaling processes.展开更多
Microorganisms carrying cbbL,pmoA and coxL genes play crucial roles in regulating soil-atmosphere exchanges of carbon trace gases(CO_(2),CH_(4),and CO).However,the geographical distribution patterns of these functiona...Microorganisms carrying cbbL,pmoA and coxL genes play crucial roles in regulating soil-atmosphere exchanges of carbon trace gases(CO_(2),CH_(4),and CO).However,the geographical distribution patterns of these functional genes in agricultural ecosystems and their environmental drivers remain poorly understood.Here,we surveyed agricultural soils across four climate zones(tropical,subtropical,warm temperate,and mid-temperate)in eastern China to quantify the abundances of CO_(2)-assimilating bacteria(cbbL gene),methanotrophs(pmoA gene),and CO-oxidizing bacteria(coxL gene).We found significant ecosystem-specific patterns:the cbbL gene was more abundant in upland soils(averaging 9.46×10^(9)copies g^(–1))than in paddy soils(6.44×10^(9) copies g^(–1)).In contrast,methanotrophs abundance was 1 to 3 orders of magnitude higher in paddy(averaging 1.17×10^(8) copies g^(–1))than in upland(5.78×10^(6)copies g^(–1))soils.The coxL gene maintained similar abundance levels across both soil types(averaging 6.12×10^(8) vs.5.91×10^(8) copies g^(–1)).Structural equation models revealed that spatial factors primarily shaped cbbL and pmoA in uplands,whereas total bacterial abundance was the dominant predictor for all three genes in paddy soils.These results highlight distinct ecological controls on microbial functional groups and provide a predictive framework for how land use and climate change may regulate microbial mediation of carbon gas fluxes across a continental-scale transect in eastern China.展开更多
To investigate the correlation between structure characteristics and wear resistance of CO2 corrosion product scales at high temperature and high pressure, an autoclave was used to prepare CO2 corrosion product scales...To investigate the correlation between structure characteristics and wear resistance of CO2 corrosion product scales at high temperature and high pressure, an autoclave was used to prepare CO2 corrosion product scales on N80 steel in carbon dioxide corrosion environment. The correlation between wear resistance of the scales and many other factors, such as temperature, pressure, morphology, structure, velocity of fluid medium, sand grain size, and so on, was comparatively analyzed by a self assembled wear device, and the scale morphologies before or after being worn were observed by scanning electron microscope （SEM）. And then the surface grain size and thickness of scale were measured. The results showed that the cross-section of the corrosion scale was of a double-layer structure, the outer layer of which was composed of regular crystals, whereas the inner layer was a thin scale of fine grains. The outer grain size and thickness of scale varied with temperature, and the initial wear loss was consistent with the surface grain size; at the same time, the total wear loss corresponded to the thickness of scale. Compared to wear resist- ance in different depths of the scale, it was found that the structure of scale was a double-layer structure in cross-section, and the wear resistance of inner layer was better than that of the outer layer; the closer the scale to the matrix, the greater was the wear resistance of scale; and the larger the size or the higher the rotary speed of solid grain in multiphase flowing medium, the more was the wear loss of scale.展开更多
Fish scale （FS） loaded TiO2 composites were investigated as photocatalysts in degradation of Methyl Orange under solar light irradiation. Composites were prepared through sol-gel method by varying mass ratio of TiO2...Fish scale （FS） loaded TiO2 composites were investigated as photocatalysts in degradation of Methyl Orange under solar light irradiation. Composites were prepared through sol-gel method by varying mass ratio of TiO2/FS at 90：10, 70：30 and 50：50, respectively. The catalysts prepared in this study were characterized by using XRD, SEM, FT-IR and nitrogen sorption. The effects of solar irradiation, mass ratio of TiO//FS composites, irradiation time and catalyst loadings were studied. Synergistic effect was found in TiO2/FS of 90：10 composite which performed higher photocatalytic degradation than synthesized TiO2 under solar light irradiation. However, further increasing fish scale content in the composites reduced the photocatalytic activity drastically. Under solar light irradiation, all the catalysts in this study exhibited photocatalytic activity, except TiO2/FS of 50：50 composite that only acted as a weak biosorbent without performing any photocatalytic property. Photocatalytic degradation increased with increasing catalyst loading and irradiation time but decreased with increased of initial dye concentration.展开更多
This article reports recent developments and advances in the simulation of the CO2-formation fluid displacement behaviour at the pore scale of subsurface porous media. Roughly, there are three effective visualization ...This article reports recent developments and advances in the simulation of the CO2-formation fluid displacement behaviour at the pore scale of subsurface porous media. Roughly, there are three effective visualization approaches to detect and observe the CO2-formation fluid displacement mechanism at the micro-scale, namely, magnetic resonance imaging, X-ray computed tomography and fabricated micromodels, but they are not capable of investigating the dis- placement process at the nano-scale. Though a lab-on-chip approach for the direct visualization of the fluid flow behaviour in nanoscale channels has been developed using an advanced epi-fluorescence microscopy method combined with a nanofluidic chip, it is still a qualitative analysis method. The lattice Boltzmann method （LBM） can simulate the CO2 displacement processes in a two-dimensional or three-dimensional （3D） pore structure, but until now, the CO2 displace- ment mechanisms had not been thoroughly investigated and the 3D pore structure of real rock had not been directly taken into account in the simulation of the CO2 displacement process. The status of research on the applications of CO2 displacement to enhance shale gas recovery is also analyzed in this paper. The coupling of molecular dynamics and LBM in tandem is proposed to simulate the CO2-shale gas displacement process based on the 3D digital model of shale obtained from focused ion beams and scanning electron microscopy.展开更多
Density, ρ, ultrasonic speed, u, and viscosity, η, of binary mixtures of 2-methyl-2-propanol (2M2P) with acetonitrile (AN), propionitrile (PN) and butyronitrile (BN) including those of pure liquids are measured over...Density, ρ, ultrasonic speed, u, and viscosity, η, of binary mixtures of 2-methyl-2-propanol (2M2P) with acetonitrile (AN), propionitrile (PN) and butyronitrile (BN) including those of pure liquids are measured over the entire composition range at temperatures 298.15, 303.15 and 308.15 K. From these experimental data, the excess available volume, E a V , excess free volume, E f V , excess isothermal compressibility, E T β , excess thermal expansion coefficient, E α , and excess internal pressure, E i π , are calculated. The variation of these properties with composition and temperature are discussed in terms of molecular interactions between unlike molecules of the mixtures. It is found that the values of E a V , E f V , E T β and E α are positive and those of E i π are negative for all the mixtures at each temperature studied, indicating the presence of weak interactions between 2M2P and AN/PN/BN molecules. The variations of E a V , E f V , E T β , E α and E i π values with composition indicate that the interactions in these mixtures follow the order: AN<PN<BN, i.e., the 2M2P-nitrile interaction decreases with the increase of alkyl chain length in these nitrile molecules. In addition, the theoretical ultrasonic velocity is calculated using the scaled particle theory and compared with the experimental values.展开更多
The study of scale up for the oxidative coupling of methane （OCM） has been carried out in a 200 ml stainless steel fixed-bed reactor over a 5wt% Na2WO4-1.9wt% Mn/SiO2 （W-Mn/SiO2） catalyst. The effects of reaction ...The study of scale up for the oxidative coupling of methane （OCM） has been carried out in a 200 ml stainless steel fixed-bed reactor over a 5wt% Na2WO4-1.9wt% Mn/SiO2 （W-Mn/SiO2） catalyst. The effects of reaction conditions were investigated in detail. The results showed that, with increasing reaction temperature, the gas-phase reaction was enhanced and a significant amount of methane was converted into COx; with the CH4/O2 molar ratio of 5, the highest C2 （ethylene and ethane） yield of 25% was achieved; the presence of steam （as diluent） had a positive effect on the C2 selectivity and yield. Under lower methane gaseous hourly space velocity （GHSV）, higher selectivity and yield of C2 were obtained as the result of the decrease of released heat energy. In 100 h reaction time, the C2 selectivity of 66%-61% and C2 yield of 24.2%-25.4% were achieved by a single pass without any significant loss in catalytic performance.展开更多
Photocatalytic degradation of organic pollutants has become a hot research topic because of its low energy consumption and environmental-friendly characteristics.Bismuth oxide(Bi2O3)nanocrystals with a bandgap ranging...Photocatalytic degradation of organic pollutants has become a hot research topic because of its low energy consumption and environmental-friendly characteristics.Bismuth oxide(Bi2O3)nanocrystals with a bandgap ranging from 2.0 eV to 2.8 eV have attracted increasing attention due to high activity of photodegradation of organic pollutants by utilizing visible light.Though several methods have been developed to prepare Bi2O3-based semiconductor materials over recent years,it is still difficult to prepare highly active Bi2O3 catalysts in large scale with a simple method.Therefore,developing simple and feasible methods for the preparation of Bi2O3 nanocrystals in large scale is important for the potential applications in industrial wastewater treatment.In this work,we successfully prepared porous Bi2O3 in large scale via etching commercial Bi Sn powders,followed by thermal treatment with air.The acquired porous Bi2O3 exhibited excellent activity and stability in photocatalytic degradation of methylene blue.Further investigation of the mechanism witnessed that the suitable band structure of porous Bi2O3 allowed the generation of reactive oxygen species,such as O2^-·and·OH,which effectively degraded MB.展开更多
Test alloys ZG40Cr24 with alloying of 3 wt% aluminium were cast by intermediate frequency induction furnace. The oxidation resistance of test alloys at 1 000 ℃ for 500 hours was examined according to oxidation weight...Test alloys ZG40Cr24 with alloying of 3 wt% aluminium were cast by intermediate frequency induction furnace. The oxidation resistance of test alloys at 1 000 ℃ for 500 hours was examined according to oxidation weight gain method. The scale morphology and composition were studied using scanning electron microscope （SEM） and X-ray diffraction （XRD） respectively. By energy dispersive spectroscopy （EDS） studies, a kind of composite oxide scale compounded highly by Cr2O3, Al2O3 and spinel MCr2O4 in molecule scale came into being at high temperature. With flat and compact structure, fine and even grains, such composite scale granted complete oxidation resistance to alloy ZG40Cr24. The oxidation resistance mechanism was studied deeply in electrochemistry corrosion. The P＋N semiconductor composite scale composed plenty of inner PN junctions, of which the unilateral conductive and the out-of-order arrangement endowed itself insulating in all directions. The positive and negative charges in scale could not move, and the mobile number and transferring rate of them both dropped enormously, as a result, the oxidation rate of the matrix metal was cut down greatly. So the composite scale presented excellent oxidation resistance.展开更多
基金Supported by the National Natural Science Foundation of China,No.82172095Qingdao Municipal Traditional Chinese Medicine Science and Technology Project,No.2022-zyym03.
文摘BACKGROUND Excessive oxidative stress plays a key role in the development of diabetic complications,including impaired ulcer healing.Previous studies have shown that fish scale ointment can promote wound healing.AIM To preliminarily investigate the effect of fish scale ointment on wound healing in a diabetic foot ulcer(DFU)rat model by examining its regulation of the nuclear factor E2-related factor 2(Nrf2)pathway and induction of ferroptosis.METHODS Fish scale ointment(collagen product)was prepared from 500 g of silver carp scales.A diabetic rat model was induced by high-fat and high-sugar feeding combined with intraperitoneal streptozotocin injections.For the DFU rat model,ulcer wounds were created by removing dorsal foot hair and cutting the skin to the fascia.The diabetic rats were randomized into five groups:Model,fish scale collagen(FSC),control+liproxstatin-1(Lip-1),model+Lip-1,and FSC+Lip-1.In each group,treatments were administered once daily by topical application and intraperitoneal injection for 14 days.Wound healing was evaluated on days 7 and 14 after treatment.Hematoxylin and eosin staining was used to assess wound injury and capillary formation.Basic fibroblast growth factor(bFGF)and CD31 levels in wound tissue were measured by immunohistochemistry.Additionally,malondialdehyde(MDA),glutathione(GSH),ferroptosis-associated genes,and iron ion concentrations were quantified using assay kits.Protein levels of Nrf2,heme oxygenase-1(HO-1),and glutathione peroxidase 4(GPX4)were determined using Western blotting.RESULTS Compared with the control group,the model group showed slower wound healing,reduced angiogenesis,decreased bFGF and CD31 levels,increased iron ion concentration and MDA levels,reduced GSH levels,and decreased Nrf2,HO-1,and GPX4 protein expression(all P<0.05).The FSC,model+Lip-1,and FSC+Lip-1 groups showed increased wound healing and angiogenesis,elevated bFGF and CD31 expression,lowered iron ion concentration and MDA levels,increased GSH levels,and enhanced Nrf2,HO-1,and GPX4 protein levels compared with the model group(P<0.05).Improvements were more pronounced in the FSC+Lip-1 group compared with the FSC group(P<0.05).CONCLUSION Fish scale ointment promotes angiogenesis and wound healing in DFU rat models by inhibiting ferroptosis,possibly through the activation of the Nrf2 pathway.
基金the support from the National Natural Science Foundation of China (51774249)the Sichuan Science and Technology Program (21JCQN0066)。
文摘To elucidate the effects of Cl^(-)and Ca^(2+) on the corrosion and scale formation of 3Cr steel in CO_(2) floodingproduced fluid,corrosion weight loss experiments,and titration experiments were conducted.The resulting products were characterized using scanning electron microscopy(SEM),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS).This study examined the corrosion and scaling behavior of 3Cr steel under the influence of Cl^(-)and Ca^(2+).The results indicate that both Cl^(-)and Ca^(2+)promote the corro sion of 3Cr steel.Notably,Cl^(-)diminishes the promoting effect of Ca^(2+)on corro sion and inhibits scaling,revealing a mutual enhancement between corrosion and scaling.The mechanisms of localized corrosion under varying concentrations of Cl^(-)and Ca^(2+)differ;under-scale corrosion occurs in environments with 5000 mg·L^(-1) Cl^(-),while Cl^(-)induced corrosion is observed in 20000 mg·L^(-1) Cl^(-)environments.This study highlights that under the synergistic effects of Cl^(-),Ca^(2+),and scaling processes,the protective product film dissolves,thereby influencing both corrosion and scaling processes.
基金financially supported by the National Key R&D Program of China(2023YFD1902802)the Science Fund for Distinguished Young Scholars in Hunan,China(2024JJ2052)+3 种基金the Natural Science Foundation of Fujian Province,China(2022J05263)the Nanping City Science and Technology Plan Project,China(NP2021KTS02)the Talent Introduction Project of Wuyi University,China(YJ202117)the Open Foundation of State Key Laboratory of Microbial Technology in Shandong University,China(M2022-05)。
文摘Microorganisms carrying cbbL,pmoA and coxL genes play crucial roles in regulating soil-atmosphere exchanges of carbon trace gases(CO_(2),CH_(4),and CO).However,the geographical distribution patterns of these functional genes in agricultural ecosystems and their environmental drivers remain poorly understood.Here,we surveyed agricultural soils across four climate zones(tropical,subtropical,warm temperate,and mid-temperate)in eastern China to quantify the abundances of CO_(2)-assimilating bacteria(cbbL gene),methanotrophs(pmoA gene),and CO-oxidizing bacteria(coxL gene).We found significant ecosystem-specific patterns:the cbbL gene was more abundant in upland soils(averaging 9.46×10^(9)copies g^(–1))than in paddy soils(6.44×10^(9) copies g^(–1)).In contrast,methanotrophs abundance was 1 to 3 orders of magnitude higher in paddy(averaging 1.17×10^(8) copies g^(–1))than in upland(5.78×10^(6)copies g^(–1))soils.The coxL gene maintained similar abundance levels across both soil types(averaging 6.12×10^(8) vs.5.91×10^(8) copies g^(–1)).Structural equation models revealed that spatial factors primarily shaped cbbL and pmoA in uplands,whereas total bacterial abundance was the dominant predictor for all three genes in paddy soils.These results highlight distinct ecological controls on microbial functional groups and provide a predictive framework for how land use and climate change may regulate microbial mediation of carbon gas fluxes across a continental-scale transect in eastern China.
基金Item Sponsored by National Natural Science Foundation of China (50231020) , National Basic Research Programof China(G1999065004) ,2001'Key Laboratory Opening Fund of Corrosion and Protection of Tabular Goods Research Center of ChinaNational Petroleum Corporation (ZYT-01070)
文摘To investigate the correlation between structure characteristics and wear resistance of CO2 corrosion product scales at high temperature and high pressure, an autoclave was used to prepare CO2 corrosion product scales on N80 steel in carbon dioxide corrosion environment. The correlation between wear resistance of the scales and many other factors, such as temperature, pressure, morphology, structure, velocity of fluid medium, sand grain size, and so on, was comparatively analyzed by a self assembled wear device, and the scale morphologies before or after being worn were observed by scanning electron microscope （SEM）. And then the surface grain size and thickness of scale were measured. The results showed that the cross-section of the corrosion scale was of a double-layer structure, the outer layer of which was composed of regular crystals, whereas the inner layer was a thin scale of fine grains. The outer grain size and thickness of scale varied with temperature, and the initial wear loss was consistent with the surface grain size; at the same time, the total wear loss corresponded to the thickness of scale. Compared to wear resist- ance in different depths of the scale, it was found that the structure of scale was a double-layer structure in cross-section, and the wear resistance of inner layer was better than that of the outer layer; the closer the scale to the matrix, the greater was the wear resistance of scale; and the larger the size or the higher the rotary speed of solid grain in multiphase flowing medium, the more was the wear loss of scale.
文摘Fish scale （FS） loaded TiO2 composites were investigated as photocatalysts in degradation of Methyl Orange under solar light irradiation. Composites were prepared through sol-gel method by varying mass ratio of TiO2/FS at 90：10, 70：30 and 50：50, respectively. The catalysts prepared in this study were characterized by using XRD, SEM, FT-IR and nitrogen sorption. The effects of solar irradiation, mass ratio of TiO//FS composites, irradiation time and catalyst loadings were studied. Synergistic effect was found in TiO2/FS of 90：10 composite which performed higher photocatalytic degradation than synthesized TiO2 under solar light irradiation. However, further increasing fish scale content in the composites reduced the photocatalytic activity drastically. Under solar light irradiation, all the catalysts in this study exhibited photocatalytic activity, except TiO2/FS of 50：50 composite that only acted as a weak biosorbent without performing any photocatalytic property. Photocatalytic degradation increased with increasing catalyst loading and irradiation time but decreased with increased of initial dye concentration.
基金The authors gratefully acknowledge the financial support of the National Natural Science Foundation of China （Grant Nos. 51374213 and 51674251）, the State Key Research Development Program of China （Grant No. 2016YFC0600705）, the National Natural Science Fund for Distinguished Young Scholars of China （Grant No. 51125017）, the Fund for Innovative Research and Development Group Program of Jiangsu Province （Grant No. 2014- 27）, the Science Fund for Creative Research Groups of the National Natural Science Foundation of China （Grant No. 51421003）, and the Priority Academic Program Development of the Jiangsu Higher Education Institutions （PAPD 2014）.
文摘This article reports recent developments and advances in the simulation of the CO2-formation fluid displacement behaviour at the pore scale of subsurface porous media. Roughly, there are three effective visualization approaches to detect and observe the CO2-formation fluid displacement mechanism at the micro-scale, namely, magnetic resonance imaging, X-ray computed tomography and fabricated micromodels, but they are not capable of investigating the dis- placement process at the nano-scale. Though a lab-on-chip approach for the direct visualization of the fluid flow behaviour in nanoscale channels has been developed using an advanced epi-fluorescence microscopy method combined with a nanofluidic chip, it is still a qualitative analysis method. The lattice Boltzmann method （LBM） can simulate the CO2 displacement processes in a two-dimensional or three-dimensional （3D） pore structure, but until now, the CO2 displace- ment mechanisms had not been thoroughly investigated and the 3D pore structure of real rock had not been directly taken into account in the simulation of the CO2 displacement process. The status of research on the applications of CO2 displacement to enhance shale gas recovery is also analyzed in this paper. The coupling of molecular dynamics and LBM in tandem is proposed to simulate the CO2-shale gas displacement process based on the 3D digital model of shale obtained from focused ion beams and scanning electron microscopy.
文摘Density, ρ, ultrasonic speed, u, and viscosity, η, of binary mixtures of 2-methyl-2-propanol (2M2P) with acetonitrile (AN), propionitrile (PN) and butyronitrile (BN) including those of pure liquids are measured over the entire composition range at temperatures 298.15, 303.15 and 308.15 K. From these experimental data, the excess available volume, E a V , excess free volume, E f V , excess isothermal compressibility, E T β , excess thermal expansion coefficient, E α , and excess internal pressure, E i π , are calculated. The variation of these properties with composition and temperature are discussed in terms of molecular interactions between unlike molecules of the mixtures. It is found that the values of E a V , E f V , E T β and E α are positive and those of E i π are negative for all the mixtures at each temperature studied, indicating the presence of weak interactions between 2M2P and AN/PN/BN molecules. The variations of E a V , E f V , E T β , E α and E i π values with composition indicate that the interactions in these mixtures follow the order: AN<PN<BN, i.e., the 2M2P-nitrile interaction decreases with the increase of alkyl chain length in these nitrile molecules. In addition, the theoretical ultrasonic velocity is calculated using the scaled particle theory and compared with the experimental values.
文摘The study of scale up for the oxidative coupling of methane （OCM） has been carried out in a 200 ml stainless steel fixed-bed reactor over a 5wt% Na2WO4-1.9wt% Mn/SiO2 （W-Mn/SiO2） catalyst. The effects of reaction conditions were investigated in detail. The results showed that, with increasing reaction temperature, the gas-phase reaction was enhanced and a significant amount of methane was converted into COx; with the CH4/O2 molar ratio of 5, the highest C2 （ethylene and ethane） yield of 25% was achieved; the presence of steam （as diluent） had a positive effect on the C2 selectivity and yield. Under lower methane gaseous hourly space velocity （GHSV）, higher selectivity and yield of C2 were obtained as the result of the decrease of released heat energy. In 100 h reaction time, the C2 selectivity of 66%-61% and C2 yield of 24.2%-25.4% were achieved by a single pass without any significant loss in catalytic performance.
基金the National Natural Science Foundation of China(No.51801235,No.11875258,No.11505187,No.51374255,No.51802356,No.51572299,and No.41701359)the Innovation-Driven Project of Central South University(No.2018CX004)+4 种基金the Start-up Funding of Central South University(No.502045005)the Fundamental Research Funds for the Central Universities(No.WK2310000066,No.WK2060190081)Posdoctoral Science Foundation of China(No.2019M652797)Central South University Postdoctoral Research Opening Fundthe Fundamental Research Funds for the Central Universities of Central South University(No.2018zzts402)。
文摘Photocatalytic degradation of organic pollutants has become a hot research topic because of its low energy consumption and environmental-friendly characteristics.Bismuth oxide(Bi2O3)nanocrystals with a bandgap ranging from 2.0 eV to 2.8 eV have attracted increasing attention due to high activity of photodegradation of organic pollutants by utilizing visible light.Though several methods have been developed to prepare Bi2O3-based semiconductor materials over recent years,it is still difficult to prepare highly active Bi2O3 catalysts in large scale with a simple method.Therefore,developing simple and feasible methods for the preparation of Bi2O3 nanocrystals in large scale is important for the potential applications in industrial wastewater treatment.In this work,we successfully prepared porous Bi2O3 in large scale via etching commercial Bi Sn powders,followed by thermal treatment with air.The acquired porous Bi2O3 exhibited excellent activity and stability in photocatalytic degradation of methylene blue.Further investigation of the mechanism witnessed that the suitable band structure of porous Bi2O3 allowed the generation of reactive oxygen species,such as O2^-·and·OH,which effectively degraded MB.
文摘Test alloys ZG40Cr24 with alloying of 3 wt% aluminium were cast by intermediate frequency induction furnace. The oxidation resistance of test alloys at 1 000 ℃ for 500 hours was examined according to oxidation weight gain method. The scale morphology and composition were studied using scanning electron microscope （SEM） and X-ray diffraction （XRD） respectively. By energy dispersive spectroscopy （EDS） studies, a kind of composite oxide scale compounded highly by Cr2O3, Al2O3 and spinel MCr2O4 in molecule scale came into being at high temperature. With flat and compact structure, fine and even grains, such composite scale granted complete oxidation resistance to alloy ZG40Cr24. The oxidation resistance mechanism was studied deeply in electrochemistry corrosion. The P＋N semiconductor composite scale composed plenty of inner PN junctions, of which the unilateral conductive and the out-of-order arrangement endowed itself insulating in all directions. The positive and negative charges in scale could not move, and the mobile number and transferring rate of them both dropped enormously, as a result, the oxidation rate of the matrix metal was cut down greatly. So the composite scale presented excellent oxidation resistance.
