To improve the anti-oxidation ability of silicon-based coating for carbon/carbon (C/C) composites at high temperatures, a ZrB2 modified silicon-based multilayer oxidation protective coating was prepared by pack ceme...To improve the anti-oxidation ability of silicon-based coating for carbon/carbon (C/C) composites at high temperatures, a ZrB2 modified silicon-based multilayer oxidation protective coating was prepared by pack cementation. The phase composition, microstructure and oxidation resistance at 1773, 1873 and 1953 K in air were investigated. The prepared coating exhibits dense structure and good oxidation protective ability. Due to the formation of stable ZrSiO4-SiO2 compound, the coating can effectively protect C/C composites from oxidation at 1773 K for more than 550 h. The anti-oxidation performance decreases with the increase of oxidation temperature. The mass loss of coated sample is 2.44% after oxidation at 1953 K for 50 h, which is attributed to the decomposition of ZrSiO4 and the volatilization of SiO2 protection layer.展开更多
[ Objective] In order to study the anti-oxidation and inhibitory effect on nonenzymatic glycation reaction of EGB fermentation extraction biotransformed by Hericium erinaceus. [ Method ] The free radical scavenging ab...[ Objective] In order to study the anti-oxidation and inhibitory effect on nonenzymatic glycation reaction of EGB fermentation extraction biotransformed by Hericium erinaceus. [ Method ] The free radical scavenging ability and reducing capacity of DPPH as well as inhibitory rate of nonenzymatic glycation reaction were measured targets for comparing changes of anti-oxidation and inhibitory effect on nonenzymatic glycation reaction of fermentation lyophilizer and fermentation extraction before and after EGB fermention adsorbed by AB-8 macroporous resin. The EGB fermention was biotransformed by Hericium erinaceus. [ Result ] After adsorbed by AB-8 macroporous resin, the bioactive matters were concentrated and separated. The free radical scavenging rate, reducing capacity and inhibitory rate of nonenzymatic glycation reaction were increased significantly after adsorbed by AB-8 macroporous resin. [ Conclusion] AB-8 macroporous resin could be used for preliminary concentration of EGB fermentation which was biotransformed by Hericium erinaceus.展开更多
Wheat germ meal is the by production of oil extracting, and a great quantity of it has been wasted, thus the quantity of lost protein is great. In order to use wheat germ meal proteins adequately, wheat germ proteins ...Wheat germ meal is the by production of oil extracting, and a great quantity of it has been wasted, thus the quantity of lost protein is great. In order to use wheat germ meal proteins adequately, wheat germ proteins were hydrolyzed to anti-oxidation peptides by using alkaline protease. Through the single factor analysis and regression analysis, the optimized experiment conditions of hydrolysising wheat germ meal to wheat germ peptides were enzymatic quantity 0.8%(w/w), material to liquid ratio 1∶12.3, enzymolysis time 2.1 h. Under these conditions, the scavenging effect was 49.78%,the DH was 22% and peptides content in enzymatic hydrolysate was 1.9%(w/w).By SDS-PAGE electrophoresis,the molecular weight range of wheat germ peptides were below 10 ku and most were between 4.54 and 5.63 ku.The wheat germ proteins could be used ful y and grain resources would be saved.展开更多
Objective To investigate the anti-hypoxia and anti-oxidation effects of aminophylline on human with acute high- altitude exposure. Mothoda Totally 100 young male army members newly recruited from Sichuan province (4...Objective To investigate the anti-hypoxia and anti-oxidation effects of aminophylline on human with acute high- altitude exposure. Mothoda Totally 100 young male army members newly recruited from Sichuan province (400 meters above sea level) were enrolled. They were randomly divided into two groups: 50 in aminophylline group (A group) and 50 in control group ( C group). A group and C group orally took aminophylline and placebo respectively for 10 days, 7 days before entering Lhasa (3 658 meters above sea level) by air and 3 days after it. Several parameters were measured at three time points: before drug taken, 7 days after drug taken, and 3 days after ascending high altitude. These parameters included serum levels of nitric oxide (NO), superoxide dismutase (SOD), catalase (CAT), hydrogen dioxide (H2O2), lactic acid (LA), as well as arterial oxygen saturation (SO2), arterial oxygen partial pressure (PaO2), and arterial carbon dioxide partial pressure (PaCO2). Statistical analysis was conducted to compare the difference between two groups with Stata 7.0 software system. Results There were no statistical differences between groups in hypoxia and oxidation indicators before and after drug taken in plain area. Three days after ascending high altitude, the serum levels of SOD, CAT, H202, LA, PaCO2 increased in both groups, yet to a much larger degree in C group than A group (P 〈0. 01 ) ; and NO, SO2 , PaO2 decreased more markedly in C group ( P 〈 0. 05 for NO, P 〈 0. 0001 for SO2 and PaO2 ). Conclusion Aminophylline has significant anti-hypoxia and anti-oxidation effects at high altitude.展开更多
A new kind of anti-oxidation inorganic nano-coating for the common low carbon steel was prepared. It included magnesite mineral, metallurgic dust and silicate adhesive as the main raw materials. The nano-coating could...A new kind of anti-oxidation inorganic nano-coating for the common low carbon steel was prepared. It included magnesite mineral, metallurgic dust and silicate adhesive as the main raw materials. The nano-coating could be sprayed directly onto the low carbon steel slab even though with hot surface as far as under 1000 ℃ . And at the same time, a compact thin nano-film was formed, and the film would inhibit the oxygen into the interface of the steel body and decrease the loss of weight because of oxidation. The loss was decreased by about 60% or more. The properties and mechanism of oxidation resistance of the coating were discussed through XRD, TG-DTA and SEM. The experimental results show that many reactions would happen among the companents of the coating and then many microspheres with the size of 80- 100nm generated in the system. By using the heat of the steel body, the silicate adhesive would interact with the microspheres, and the other components of the coating would be soft and sintered so that when the coating was sprayed onto the suface of the steel slab , the intact and compact film could be formed and adhesive with the steel body. Besides the special properties of anti- oxidation, the coating could prevent the volatilization of microelement in the steel such as silicate and carbon at a high temperature. So it can improve the quality and output of steel with this new kind of nano-coating.展开更多
A Mo-Si-C-N multi-layered anti-oxidation coating was in-situ fabricated by introducing nitrogen atmosphere during the fused sintering of Mo-Si slurry pre-layer on carbon/carbon composites. The phase composition and mi...A Mo-Si-C-N multi-layered anti-oxidation coating was in-situ fabricated by introducing nitrogen atmosphere during the fused sintering of Mo-Si slurry pre-layer on carbon/carbon composites. The phase composition and microstructure of the Mo-Si-C-N coating were characterized by X-ray diffractometry, optical microscopy, scanning electron microscopy with energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. The Mo-Si-C-N coating exhibited a three-layered structure. Besides the MoSi2/Si main-layer and the SiC bonding-layer, a surface layer of about 10 μm in thickness was synthesized on the coating surface. The surface layer mainly consisted of SiC nanowires and contained some Si3N4 and Si phases. SiC nanowires of 10 to 200 nm in diameter presented a terrace and distortion structure. Transmission electron microscopy indicated that the SiC nanowires grew along the preferred 〈111〉 direction. During oxidation test, SiC nanowires transmuted into SiO2 glass, which can play an important role in improving the oxidation resistance of C/C composites.展开更多
Industrial spent MoSi_(2)-based materials were used to fabricate oxidation-resistant coatings on molybdenum via slurry painting in air. The microstructure, phase constituent and high-temperature oxidation behaviors of...Industrial spent MoSi_(2)-based materials were used to fabricate oxidation-resistant coatings on molybdenum via slurry painting in air. The microstructure, phase constituent and high-temperature oxidation behaviors of the coatings at 1500 ℃ were explored. The results show that the bonding layer is generated in the coatings after sintering,which strengthens the metallurgical combination between the coating and the substrate because of the formation of diffusion layers. Rare cracks appear in the coating using pure MoSi_(2)(PM coating) while the coating using spent MoSi_(2)(SM coating) is free of cracks due to decreased thermal expansion mismatch. After oxidation, the oxide scale of PM coating possesses large-sized pores while a relatively dense oxide scale is acquired by SM coating. Compared with PM coating, thinner glassy oxide scale with lower mass gain is obtained by SM coating, exhibiting better anti-oxidation properties at 1500 ℃.展开更多
In order to enhance the oxidation resistance of C/Si C composites, mullite/yttrium silicate coatings were fabricated on C/Si C composites through dip-coating route. Al_2O_3-SiO_2 sol with high solid content was select...In order to enhance the oxidation resistance of C/Si C composites, mullite/yttrium silicate coatings were fabricated on C/Si C composites through dip-coating route. Al_2O_3-SiO_2 sol with high solid content was selected as the raw material for mullite and "silicone resin + Y_2O_3 powder" slurry was used to synthesize yttrium silicate. The microstructure and phase composition of coatings were characterized, and the investigation on oxidation resistance and anti-oxidation mechanism was emphasized. The as-fabricated coatings consisting of SiO_2-rich mullite phase and Y_2Si_2O_7 phase show high density and favorable bonding to C/Si C composites. After oxidized at 1 400 ℃ and 1 500 ℃ for 30 min in static air, the coating-containing C/Si C composites possess 91.9% and 102.4% of the original flexural strength, respectively. The desirable thermal stability of coatings and the further densification of coatings due to viscous flow of rich SiO_2 and Y-Si-Al-O glass are responsible for the excellent oxidation resistance. In addition, the coating-containing composites retain 99.0% of the original flexural strength and the coatings exhibit no cracking and desquamation after 12 times of thermal shock from 1 400 ℃ to room temperature, which are ascribed to the combination of anti-oxidation mechanism and preferable physical and chemical compatibility among C/Si C composites, mullite and Y_2Si_2O_7. The carbothermal reaction at 1 600 ℃ between free carbon in C/Si C substrate and rich SiO_2 in mullite results in severe frothing and desquamation of coatings and obvious degradation in oxidation resistance.展开更多
[Objectives]To optimize the extraction technology of total flavonoids component,and investigate its in vitro anti-oxidation activity.[Methods]The single factor was inspected firstly. By orthogonal experiment,the best ...[Objectives]To optimize the extraction technology of total flavonoids component,and investigate its in vitro anti-oxidation activity.[Methods]The single factor was inspected firstly. By orthogonal experiment,the best extraction conditions of total flavonoids from fruits and leaves of P. mume Sieb. et Zucc. were determined,and reducing ability of the extracted total flavonoids and its DPPH and ABTS scavenging abilities were explored. [Results] The best extraction technology conditions: solid-liquid ratio of 1∶ 50,ethanol concentration of 50%,extraction time of 2. 5 h,extraction temperature of 85 ℃,two-time extraction. By detecting DPPH and ABTS scavenging abilities of total flavonoids,the anti-oxidation activity of the total flavonoids from fruits and leaves of P. mume Sieb. et Zucc. was analyzed and evaluated. [Conclusions]Fruits and leaves of P. mume Sieb. et Zucc. had a certain in vitro anti-oxidation activity,and heat reflux extraction method of its total flavonoids had high extraction rate and simple and convenient operation,which had some practical value.展开更多
[Objectives]To study content of total saponins from cultivated and wild Paris herbs in Southwest China,evaluate its in vitro antioxidation activity,and explore the correlation between quality of Paris herbs and produc...[Objectives]To study content of total saponins from cultivated and wild Paris herbs in Southwest China,evaluate its in vitro antioxidation activity,and explore the correlation between quality of Paris herbs and production place,variety,cultivated and wild varieties.[Methods]Colorimetric method of perchloric acid reaction was used,and content of total saponins from Paris herbs was determined by ultraviolet spectrophotometer at 406 nm. [Results]The lowest content of total saponins from cultivated and wild Paris herbs in Southwest China was0. 55%,while the maximum was 12. 24%,with obvious difference. Total saponins from Paris herbs had stronger clearance ability on free radical DPPH and stronger reduction ability on Fe^(3+),and the results showed good dose-effect relationship with concentration. Among them,S6 had the highest clearance ability on DPPH,which reached 89. 66%. In the determination of reduction ability,the absorbance of S16 reached3. 643 and was the highest,with very good reducing property. Content and anti-oxidation capacity of total saponins from Paris herbs in Southwest China did not have obvious correlation with production place,altitude and cultivation but was related to variety. [Conclusions]The quality of Paris herbs in Southwest China was unstable,and their anti-oxidation abilities were also different,and cultivation could not guarantee high quality. It should normalize cultivation,and develop planting industry of Paris herbs,which could guarantee stable supply of Paris herbs and stability and controllability of quality.展开更多
Stoichiometric and silicon-rich(Si-rich) SiC films were deposited by microwave electron cyclotron resonance(MWECR) plasma enhanced RF magnetron sputtering method.As-deposited films were oxidized at 800℃,900 ℃,and 10...Stoichiometric and silicon-rich(Si-rich) SiC films were deposited by microwave electron cyclotron resonance(MWECR) plasma enhanced RF magnetron sputtering method.As-deposited films were oxidized at 800℃,900 ℃,and 1000 ℃in air for 60 min.The chemical composition and structure of the films were analyzed by x-ray photoelectron spectroscopy(XPS),Raman spectroscopy and Fourier transform infrared spectroscopy(FT-IR).The surface morphology of the films before and after the high temperature oxidation was measured by atomic force microscopy.The mechanical property of the films was measured by a nano-indenter.The anti-oxidation temperature of the Si-rich SiC film is 100 ℃ higher than that of the stoichiometric SiC film.The oxidation layer thickness of the Si-rich SiC film is thinner than that of the stoichiometric SiC film in depth direction.The large amount of extra silicon in the Si-rich SiC film plays an important role in the improvement of its high temperature anti-oxidation property.展开更多
基金Projects(51221001,50972120)supported by the National Natural Science Foundation of ChinaProject(73-QP-2010)supported by the Research Fund of the State Key Laboratory of Solidification Processing of Northwestern Polytechnical University,ChinaProject(B08040)supported by Program of Introducing Talents of Discipline to Universities,China
文摘To improve the anti-oxidation ability of silicon-based coating for carbon/carbon (C/C) composites at high temperatures, a ZrB2 modified silicon-based multilayer oxidation protective coating was prepared by pack cementation. The phase composition, microstructure and oxidation resistance at 1773, 1873 and 1953 K in air were investigated. The prepared coating exhibits dense structure and good oxidation protective ability. Due to the formation of stable ZrSiO4-SiO2 compound, the coating can effectively protect C/C composites from oxidation at 1773 K for more than 550 h. The anti-oxidation performance decreases with the increase of oxidation temperature. The mass loss of coated sample is 2.44% after oxidation at 1953 K for 50 h, which is attributed to the decomposition of ZrSiO4 and the volatilization of SiO2 protection layer.
基金the Natural Science Foundation of Jiangsu Province (BK2003047)~~
文摘[ Objective] In order to study the anti-oxidation and inhibitory effect on nonenzymatic glycation reaction of EGB fermentation extraction biotransformed by Hericium erinaceus. [ Method ] The free radical scavenging ability and reducing capacity of DPPH as well as inhibitory rate of nonenzymatic glycation reaction were measured targets for comparing changes of anti-oxidation and inhibitory effect on nonenzymatic glycation reaction of fermentation lyophilizer and fermentation extraction before and after EGB fermention adsorbed by AB-8 macroporous resin. The EGB fermention was biotransformed by Hericium erinaceus. [ Result ] After adsorbed by AB-8 macroporous resin, the bioactive matters were concentrated and separated. The free radical scavenging rate, reducing capacity and inhibitory rate of nonenzymatic glycation reaction were increased significantly after adsorbed by AB-8 macroporous resin. [ Conclusion] AB-8 macroporous resin could be used for preliminary concentration of EGB fermentation which was biotransformed by Hericium erinaceus.
文摘Wheat germ meal is the by production of oil extracting, and a great quantity of it has been wasted, thus the quantity of lost protein is great. In order to use wheat germ meal proteins adequately, wheat germ proteins were hydrolyzed to anti-oxidation peptides by using alkaline protease. Through the single factor analysis and regression analysis, the optimized experiment conditions of hydrolysising wheat germ meal to wheat germ peptides were enzymatic quantity 0.8%(w/w), material to liquid ratio 1∶12.3, enzymolysis time 2.1 h. Under these conditions, the scavenging effect was 49.78%,the DH was 22% and peptides content in enzymatic hydrolysate was 1.9%(w/w).By SDS-PAGE electrophoresis,the molecular weight range of wheat germ peptides were below 10 ku and most were between 4.54 and 5.63 ku.The wheat germ proteins could be used ful y and grain resources would be saved.
文摘Objective To investigate the anti-hypoxia and anti-oxidation effects of aminophylline on human with acute high- altitude exposure. Mothoda Totally 100 young male army members newly recruited from Sichuan province (400 meters above sea level) were enrolled. They were randomly divided into two groups: 50 in aminophylline group (A group) and 50 in control group ( C group). A group and C group orally took aminophylline and placebo respectively for 10 days, 7 days before entering Lhasa (3 658 meters above sea level) by air and 3 days after it. Several parameters were measured at three time points: before drug taken, 7 days after drug taken, and 3 days after ascending high altitude. These parameters included serum levels of nitric oxide (NO), superoxide dismutase (SOD), catalase (CAT), hydrogen dioxide (H2O2), lactic acid (LA), as well as arterial oxygen saturation (SO2), arterial oxygen partial pressure (PaO2), and arterial carbon dioxide partial pressure (PaCO2). Statistical analysis was conducted to compare the difference between two groups with Stata 7.0 software system. Results There were no statistical differences between groups in hypoxia and oxidation indicators before and after drug taken in plain area. Three days after ascending high altitude, the serum levels of SOD, CAT, H202, LA, PaCO2 increased in both groups, yet to a much larger degree in C group than A group (P 〈0. 01 ) ; and NO, SO2 , PaO2 decreased more markedly in C group ( P 〈 0. 05 for NO, P 〈 0. 0001 for SO2 and PaO2 ). Conclusion Aminophylline has significant anti-hypoxia and anti-oxidation effects at high altitude.
文摘A new kind of anti-oxidation inorganic nano-coating for the common low carbon steel was prepared. It included magnesite mineral, metallurgic dust and silicate adhesive as the main raw materials. The nano-coating could be sprayed directly onto the low carbon steel slab even though with hot surface as far as under 1000 ℃ . And at the same time, a compact thin nano-film was formed, and the film would inhibit the oxygen into the interface of the steel body and decrease the loss of weight because of oxidation. The loss was decreased by about 60% or more. The properties and mechanism of oxidation resistance of the coating were discussed through XRD, TG-DTA and SEM. The experimental results show that many reactions would happen among the companents of the coating and then many microspheres with the size of 80- 100nm generated in the system. By using the heat of the steel body, the silicate adhesive would interact with the microspheres, and the other components of the coating would be soft and sintered so that when the coating was sprayed onto the suface of the steel slab , the intact and compact film could be formed and adhesive with the steel body. Besides the special properties of anti- oxidation, the coating could prevent the volatilization of microelement in the steel such as silicate and carbon at a high temperature. So it can improve the quality and output of steel with this new kind of nano-coating.
基金supported by the Foundation of Heilongjiang Province (No. LC04C16)the Foundation of Aerospace Technology (No. HTJSZC-0506) the Post-Doctor Foundation of Heilongjiang Province, China
文摘A Mo-Si-C-N multi-layered anti-oxidation coating was in-situ fabricated by introducing nitrogen atmosphere during the fused sintering of Mo-Si slurry pre-layer on carbon/carbon composites. The phase composition and microstructure of the Mo-Si-C-N coating were characterized by X-ray diffractometry, optical microscopy, scanning electron microscopy with energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. The Mo-Si-C-N coating exhibited a three-layered structure. Besides the MoSi2/Si main-layer and the SiC bonding-layer, a surface layer of about 10 μm in thickness was synthesized on the coating surface. The surface layer mainly consisted of SiC nanowires and contained some Si3N4 and Si phases. SiC nanowires of 10 to 200 nm in diameter presented a terrace and distortion structure. Transmission electron microscopy indicated that the SiC nanowires grew along the preferred 〈111〉 direction. During oxidation test, SiC nanowires transmuted into SiO2 glass, which can play an important role in improving the oxidation resistance of C/C composites.
基金financially supported by the National Natural Science Foundation of China (Nos. 51874305, 51972338)Graduate Research and Innovation Projects of Jiangsu Province, China (No. KYCX21_22413)。
文摘Industrial spent MoSi_(2)-based materials were used to fabricate oxidation-resistant coatings on molybdenum via slurry painting in air. The microstructure, phase constituent and high-temperature oxidation behaviors of the coatings at 1500 ℃ were explored. The results show that the bonding layer is generated in the coatings after sintering,which strengthens the metallurgical combination between the coating and the substrate because of the formation of diffusion layers. Rare cracks appear in the coating using pure MoSi_(2)(PM coating) while the coating using spent MoSi_(2)(SM coating) is free of cracks due to decreased thermal expansion mismatch. After oxidation, the oxide scale of PM coating possesses large-sized pores while a relatively dense oxide scale is acquired by SM coating. Compared with PM coating, thinner glassy oxide scale with lower mass gain is obtained by SM coating, exhibiting better anti-oxidation properties at 1500 ℃.
基金Funded by the Aid Program for Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Provincethe Aid Program for Innovative Group of National University of Defense Technologythe Science Innovation Foundation of Shanghai Academy of Spaceflight Technology(No.SAST2015043)
文摘In order to enhance the oxidation resistance of C/Si C composites, mullite/yttrium silicate coatings were fabricated on C/Si C composites through dip-coating route. Al_2O_3-SiO_2 sol with high solid content was selected as the raw material for mullite and "silicone resin + Y_2O_3 powder" slurry was used to synthesize yttrium silicate. The microstructure and phase composition of coatings were characterized, and the investigation on oxidation resistance and anti-oxidation mechanism was emphasized. The as-fabricated coatings consisting of SiO_2-rich mullite phase and Y_2Si_2O_7 phase show high density and favorable bonding to C/Si C composites. After oxidized at 1 400 ℃ and 1 500 ℃ for 30 min in static air, the coating-containing C/Si C composites possess 91.9% and 102.4% of the original flexural strength, respectively. The desirable thermal stability of coatings and the further densification of coatings due to viscous flow of rich SiO_2 and Y-Si-Al-O glass are responsible for the excellent oxidation resistance. In addition, the coating-containing composites retain 99.0% of the original flexural strength and the coatings exhibit no cracking and desquamation after 12 times of thermal shock from 1 400 ℃ to room temperature, which are ascribed to the combination of anti-oxidation mechanism and preferable physical and chemical compatibility among C/Si C composites, mullite and Y_2Si_2O_7. The carbothermal reaction at 1 600 ℃ between free carbon in C/Si C substrate and rich SiO_2 in mullite results in severe frothing and desquamation of coatings and obvious degradation in oxidation resistance.
基金Supported by 2014 Sichuan Science and Technology Support Plan Program(2014SZ0131)Education Innovation Project of Southwest Minzu University(2015)
文摘[Objectives]To optimize the extraction technology of total flavonoids component,and investigate its in vitro anti-oxidation activity.[Methods]The single factor was inspected firstly. By orthogonal experiment,the best extraction conditions of total flavonoids from fruits and leaves of P. mume Sieb. et Zucc. were determined,and reducing ability of the extracted total flavonoids and its DPPH and ABTS scavenging abilities were explored. [Results] The best extraction technology conditions: solid-liquid ratio of 1∶ 50,ethanol concentration of 50%,extraction time of 2. 5 h,extraction temperature of 85 ℃,two-time extraction. By detecting DPPH and ABTS scavenging abilities of total flavonoids,the anti-oxidation activity of the total flavonoids from fruits and leaves of P. mume Sieb. et Zucc. was analyzed and evaluated. [Conclusions]Fruits and leaves of P. mume Sieb. et Zucc. had a certain in vitro anti-oxidation activity,and heat reflux extraction method of its total flavonoids had high extraction rate and simple and convenient operation,which had some practical value.
基金Supported by Sichuan Science and Technology Support Plan(2016FZ0045)Sichuan Key Technology Innovation Project Plan(2014XM041)Research and Development Fund of Application Technology in Aba Prefecture(2015)
文摘[Objectives]To study content of total saponins from cultivated and wild Paris herbs in Southwest China,evaluate its in vitro antioxidation activity,and explore the correlation between quality of Paris herbs and production place,variety,cultivated and wild varieties.[Methods]Colorimetric method of perchloric acid reaction was used,and content of total saponins from Paris herbs was determined by ultraviolet spectrophotometer at 406 nm. [Results]The lowest content of total saponins from cultivated and wild Paris herbs in Southwest China was0. 55%,while the maximum was 12. 24%,with obvious difference. Total saponins from Paris herbs had stronger clearance ability on free radical DPPH and stronger reduction ability on Fe^(3+),and the results showed good dose-effect relationship with concentration. Among them,S6 had the highest clearance ability on DPPH,which reached 89. 66%. In the determination of reduction ability,the absorbance of S16 reached3. 643 and was the highest,with very good reducing property. Content and anti-oxidation capacity of total saponins from Paris herbs in Southwest China did not have obvious correlation with production place,altitude and cultivation but was related to variety. [Conclusions]The quality of Paris herbs in Southwest China was unstable,and their anti-oxidation abilities were also different,and cultivation could not guarantee high quality. It should normalize cultivation,and develop planting industry of Paris herbs,which could guarantee stable supply of Paris herbs and stability and controllability of quality.
文摘Stoichiometric and silicon-rich(Si-rich) SiC films were deposited by microwave electron cyclotron resonance(MWECR) plasma enhanced RF magnetron sputtering method.As-deposited films were oxidized at 800℃,900 ℃,and 1000 ℃in air for 60 min.The chemical composition and structure of the films were analyzed by x-ray photoelectron spectroscopy(XPS),Raman spectroscopy and Fourier transform infrared spectroscopy(FT-IR).The surface morphology of the films before and after the high temperature oxidation was measured by atomic force microscopy.The mechanical property of the films was measured by a nano-indenter.The anti-oxidation temperature of the Si-rich SiC film is 100 ℃ higher than that of the stoichiometric SiC film.The oxidation layer thickness of the Si-rich SiC film is thinner than that of the stoichiometric SiC film in depth direction.The large amount of extra silicon in the Si-rich SiC film plays an important role in the improvement of its high temperature anti-oxidation property.