Free radicals in ischemic and reperfused rat brain were measured by electron spinresonance(ESR) spectrometer.The inhibitory effect of allopurinol on the free radical genera-tion in reperfused rat brain was observed.Th...Free radicals in ischemic and reperfused rat brain were measured by electron spinresonance(ESR) spectrometer.The inhibitory effect of allopurinol on the free radical genera-tion in reperfused rat brain was observed.The experimental results revealed that the free radi-cal content of the brain in the ischemia group was markedly higher than that in the control group(P【0.01),that in the reperfusion group was markedly higher than that in the ischemia group(P【0.01)and that in the allopurinol group was markedly lower than that in the reperfusiongroup(P【0.01).These results suggest that free radicals increase.greatly after cerebralischemia-reperfusion and that allopurinol plays a certain inhibitory role in the free radical genera-tion in the reperfused rat brain.展开更多
Pyrolysis of cyclohexane was conducted with a plug flow tube reactor in the temperature range of 873-973 K. Based on the experimental data, the mechanism and kinetic model of cyclohexane pyrolysis reaction were propos...Pyrolysis of cyclohexane was conducted with a plug flow tube reactor in the temperature range of 873-973 K. Based on the experimental data, the mechanism and kinetic model of cyclohexane pyrolysis reaction were proposed. The kinetic analysis shows that overall conversion of cyclohexane is a first order reaction, of which the rate constant increased from 0.0086 to 0.0225 to 0.0623 s-1 with the increase of temperature from 873 to 923 to 973 K, and the apparent activation energy was determined to be 155.0±1.0 kJ mol-1. The mechanism suggests that the cyclohexane is consumed by four processes：the homolysis of C-C bond （Path I）, the homolysis of C-H bond （Path II） in reaction chain initia- tion, the H-abstraction of various radicals from the feed molecules in reaction chain propagation （Path III）, and the process associated with coke formation （Path IV）. The reaction path probability （RPP） ratio of XPath I：XPath II ： XPath III ： XPath IV was 0.5420：0.0045：0.3897：0.0638 at 873 K, and 0.4336 ： 0.0061 ： 0.4885 ： 0.0718 at 973 K, respectively.展开更多
A model of burn shock was reproduced in rats and the changes of water content andmalondialdehyde(MDA)concentration in tissues were measured.The results showed that there wasa significant increase of MDA concentration ...A model of burn shock was reproduced in rats and the changes of water content andmalondialdehyde(MDA)concentration in tissues were measured.The results showed that there wasa significant increase of MDA concentration and water content in lung and bumed skin post burnand a positive correlation was found between MDA level and water content.Pretreatment withsuperoxide dismutase(SOD)prevented effectively lung and skin from edema.The role of oxygen freeradicals in vascular permeability disturbance and development of edema in burns was discussed.展开更多
A new series of Schiff base ligands were synthesized by the condensation of 2-amino-5-mercaptan-l,3,4-thiadiazole and salicylaldehyde or 2,4-dihydroxybenzaldehyde and their derivatives with choroacetic acid, and furth...A new series of Schiff base ligands were synthesized by the condensation of 2-amino-5-mercaptan-l,3,4-thiadiazole and salicylaldehyde or 2,4-dihydroxybenzaldehyde and their derivatives with choroacetic acid, and further reaction with corresponding metal acetate to form metal complexes. The compositions and structures of the ligands and their complexes were characterized by elemental analysis, molar conductivities, electronic absorption spectra and infra-red spectra. Their inhibition rates to free radical, such as O2, were also tested. The results show that all of the obtained complexes display significant activities, among which the copper（Ⅱ） complexes have the best inhibitive effects.展开更多
The extracts from leaves of Manglietia insignis （Wall） Blume, Manglietia chingii Dandy and Manglietia yuyuanensis Law were prepared by organic solvent extraction and their components were analyzed by GC/MS and quant...The extracts from leaves of Manglietia insignis （Wall） Blume, Manglietia chingii Dandy and Manglietia yuyuanensis Law were prepared by organic solvent extraction and their components were analyzed by GC/MS and quantified. Meanwhile, the free radicals restraining activities were detected. The 21 compounds in M. insignis, 36 compounds in M. chigii and 20 compounds in M. yuyuanensis were identified. There were 11 common components in the extracts from three Manglietia species, and 12 components in two Manglietia species. The results of relative contents of every component in three extracts showed that the main constituents of M. insignis were terpenoids and alkene, amounting to 38.93%, followed by alkane （28.18%）, the nitrogen containing compounds （15.73%） and aromatic compounds （7.23 %）. The main constituents of leaf extract from M. chingii were the terpenoids and alkene, carboxylic acid, alkane and aromatic compounds, amounting to 30.22%, 14.17%, 13.87% and 13.29%, respectively, The main constituents of M. yuyuanensis were alcohol compounds, the terpenoids and alkene, and aromatic compounds, amounting to 28.00%, 25.38% and 18.00% respectively. The results showed that the three extracts had strong function of restraining oxygen free radicals. The ultra oxygen anions activity was restrained at the highest level, when the three extracts were diluted by hundred-fold, whereas the restraining capacity of hydroxyl free radicals reached maximum, when the three extracts were diluted by twenty-fold. The above results provide scientific evidences for further approaching the ecological healthy function of three MangUetia species展开更多
Owing to the high oxygen-respiration in the brain of mammals, oxidative damage to prion protein hasbeen suggested to be an additional factor. A large body of intriguing features of scrapie and prion diseases haveprovi...Owing to the high oxygen-respiration in the brain of mammals, oxidative damage to prion protein hasbeen suggested to be an additional factor. A large body of intriguing features of scrapie and prion diseases haveprovided multiple lines of indirect chemistry evidence, suggesting that the infectious agents may be putative forms ofsequence-specific prion radicals (SSPR) and/or their immediate precursors in the transmissible spongiform encepha-lopathies (TSE). Here a molecular mechanism corresponding to the self-replication of scrapie protein mediated byprion free-radical processes, consonant with "protein-only" hypotheses is proposed. This new theory may not onlyaid our understanding of the occurrence of prions, but also provides new insight into the possible chemistry principlesunderlying the neurodegenerative disorders. It is anticipated that future studies based on this suggestion and chem-istry principles of genetic diseases may allow us to determine an effective approach to stop mad cow disease and itshuman version, new variant of Creutzfeldt-Jakob disease (v CJD).展开更多
The inhibiting effects of CHinonin,Quercetin and Tannic Acid on the lipid oxidation (LPO) induced by irradiation were investigated by means of a modified TBA spectrophotometry.The scavenging effects of theses three ac...The inhibiting effects of CHinonin,Quercetin and Tannic Acid on the lipid oxidation (LPO) induced by irradiation were investigated by means of a modified TBA spectrophotometry.The scavenging effects of theses three active compounds on free radicals were studied by ESR technique.The results showed that antioxidation effects of Chinonin and Quercetin were better than that of Tannic Acid;though scavenging effects of the threee active compounds were similar.展开更多
Objective: To investigate the effect of ultraviolet blood irradiation and oxygenation (UBIO) on the metabolism of oxygen free radicals in rabbits with acute soman intoxication. Methods: One hundred rabbits were random...Objective: To investigate the effect of ultraviolet blood irradiation and oxygenation (UBIO) on the metabolism of oxygen free radicals in rabbits with acute soman intoxication. Methods: One hundred rabbits were randomly divided into 5 groups: normal control group, intoxication group, routine therapy group. UBIO therapy group and combined therapy group. After 14 d, the concentration of malondiadehyde(MDA) and activity of superoxide dismutase(SOD), glutathionperoxidase(GSH-Px), catalase (CAT) and total antioxidative capacity (T-AOC) in serum were determined respectively. Results: Compared with the normal control group, the concentration of MDA and activity of CAT in the intoxication group were significantly higher (P < 0. 05). but SOD. GSH-Px activity and T-AOC were significantly lower (P<0. 05). After UBIO or combined therapy, serum MDA level was significantly lower in comparison with intoxication group (P<0. 05). but the activity of SOD. GSH-Px, CAT and T-AOC were higher than intoxication group(P<0. 05). Conclusion: There is an obvious oxygen free radical injury in rabbits with a-cute soman intoxication. UBIO can improve the antioxidation ability of rabbits and may be applied to treat acute soman intoxication as adjunctive therapy.展开更多
Recent advancements in additive manufacturing(AM)have revolutionized the design and production of complex engineering microstructures.Despite these advancements,their mathematical modeling and computational analysis r...Recent advancements in additive manufacturing(AM)have revolutionized the design and production of complex engineering microstructures.Despite these advancements,their mathematical modeling and computational analysis remain significant challenges.This research aims to develop an effective computational method for analyzing the free vibration of functionally graded(FG)microplates under high temperatures while resting on a Pasternak foundation(PF).This formulation leverages a new thirdorder shear deformation theory(new TSDT)for improved accuracy without requiring shear correction factors.Additionally,the modified couple stress theory(MCST)is incorporated to account for sizedependent effects in microplates.The PF is characterized by two parameters including spring stiffness(k_(w))and shear layer stiffness(k_(s)).To validate the proposed method,the results obtained are compared with those of the existing literature.Furthermore,numerical examples explore the influence of various factors on the high-temperature free vibration of FG microplates.These factors include the length scale parameter(l),geometric dimensions,material properties,and the presence of the elastic foundation.The findings significantly enhance our comprehension of the free vibration of FG microplates in high thermal environments.In addition,the findings significantly enhance our comprehension of the free vibration of FG microplates in high thermal environments.In addition,the results of this research will have great potential in military and defense applications such as components of submarines,fighter aircraft,and missiles.展开更多
The effects of anthocyanin from Mah,a sylvestris on plasma lipids and free radical were investigated by Reagent Kit method and in vitro assay. High tat model was set up with albino rats that were fed with different do...The effects of anthocyanin from Mah,a sylvestris on plasma lipids and free radical were investigated by Reagent Kit method and in vitro assay. High tat model was set up with albino rats that were fed with different dosages of anthocyanin from Malva sylvestris 10.03 g·d^-1, 0.04 g·d ^-1 and 0.05 g·d^-1）. The results showed that the total cholesterol was decreased by 19.7% at an anthocyanin of 0.04 g. d and triglyceride was decreased by 34.4% at an anthocyanin of 0.05 g·d^-1. In vitro assay, some indexes of anthocyanin were measured including the capability of scavenging free radical, reducing force and the capability of anti-lipid peroxidation by orthophenanthroline Fe^＋2 oxidation-reduction method. The results indicated that the clearance rate of free radical reached to 43.46% when the content of anthocyanin was 0.20 mg·mL^-1 and the inhibition ratio of lipid peroxidation reached 18.82% when the content was 0.5 mg·mL^-1. Therefore anthocyanin is a kind of natural and effective free radical remover and antioxidant and can prevent from the formation of the thrombus and reduced the emergence of the cardiovascular disease.展开更多
The chemical activation of various precursors is effective for creating additional closed pores in hard carbons for sodium storage.However,the formation mechanism of closed pores under the influence of pore-forming ag...The chemical activation of various precursors is effective for creating additional closed pores in hard carbons for sodium storage.However,the formation mechanism of closed pores under the influence of pore-forming agents is not well understood.Herein,an effective chemical activation followed by a high-temperature self-healing strategy is employed to generate interconnected closed pores in lignin-derived hard carbon(HCs).By systematic experimental design combined with electron paramagnetic res-onance spectroscopy,it can be found that the content of free radicals in the carbon matrix influences the closure of open pores at high temperatures.Excessively high activation temperature(>700 C)leads to a low free radical concentration,making it difficult to achieve self-healing of open pores at high tempera-tures.By activation at 700°C,a balance between pore making and self-healing is achieved in the final hard carbon.A large number of free radicals triggers rapid growth and aggregation of carbon microcrys-tals,blocking pre-formed open micropores and creating additional interconnected closed pores in as-obtained hard carbons.As a result,the optimized carbon anode(LK-700-1300)delivers a high reversible capacity of 330.8 mA h g^(-1) at 0.03 A g^(-1),which is an increase of 86 mA h g^(-1) compared to the pristine lignin-derived carbon anode(L-700-1300),and exhibits a good rate performance(202.1 mA h g^(-1) at 1 A g^(-1)).This work provides a universal and effective guidance for tuning closed pores of hard carbons from otherprecursors.展开更多
We build a partition function model by product approximation first,then put the normal temperature calculated by moment square R^(2)/_(V),which has no rotational transition,approximately as a constant and applied to h...We build a partition function model by product approximation first,then put the normal temperature calculated by moment square R^(2)/_(V),which has no rotational transition,approximately as a constant and applied to high temperature,and lastly program the compiler and compute the spectral line intensities and absorption coefficients of the 001-000 band for the hydride BH_(2) free radical molecule at several temperatures.The results show that the calculated values of total partition function agree with the data obtained from Gauss calculations and the fitted values by five factorial polynomials.Such excellent agreement has made it feasible to calculate the spectral line intensities and absorption coefficients at different temperatures.From the spectral figures at different temperatures,we find that they accord with the spectrum characteristic of asymmetric top molecules in some literature.This analysis has significance in measuring the high-temperature spectrum intensities of radical molecules by experiment.展开更多
The correlation of oxygen free radical items between blood and kidney of 5/6 nephrectomy-induced chronic renal failure rats was studied. It was found that oxygen free radicals played an important role in the impairmen...The correlation of oxygen free radical items between blood and kidney of 5/6 nephrectomy-induced chronic renal failure rats was studied. It was found that oxygen free radicals played an important role in the impairment of remnant kidney,and antioxidant vitamin E could protect remnant kidney from the impairment caused by oxygen free radicals,and that,both in normal and chronic renal failure conditions,plasma lipid peroxides and vitamin E concentration and superoxide dismutase activity of red blood cells correlated very well with corresponding items of remnant kidney.These results suggested that blood oxygen free radical items could reflect renal oxygen free radical metabolic status in chronic renal failure patients.展开更多
The structures in engineering can be simplified into elastic beams with concentrated masses and elastic spring supports. Studying the law of vibration of the beams can be a help in guiding its design and avoiding reso...The structures in engineering can be simplified into elastic beams with concentrated masses and elastic spring supports. Studying the law of vibration of the beams can be a help in guiding its design and avoiding resonance. Based on the Laplace transform method, the mode shape functions and the frequency equations of the beams in the typical boundary conditions are derived. A cantilever beam with a lumped mass and a spring is selected to obtain its natural frequencies and mode shape functions. An experiment was conducted in order to get the modal parameters of the beam based on the NExT-ERA method. By comparing the analytical and experimental results, the effects of the locations of the mass and spring on the modal parameter are discussed. The variation of the natural frequencies was obtained with the changing stiffness coefficient and mass coefficient, respectively. The findings provide a reference for the vibration analysis methods and the lumped parameters layout design of elastic beams used in engineering.展开更多
文摘Free radicals in ischemic and reperfused rat brain were measured by electron spinresonance(ESR) spectrometer.The inhibitory effect of allopurinol on the free radical genera-tion in reperfused rat brain was observed.The experimental results revealed that the free radi-cal content of the brain in the ischemia group was markedly higher than that in the control group(P【0.01),that in the reperfusion group was markedly higher than that in the ischemia group(P【0.01)and that in the allopurinol group was markedly lower than that in the reperfusiongroup(P【0.01).These results suggest that free radicals increase.greatly after cerebralischemia-reperfusion and that allopurinol plays a certain inhibitory role in the free radical genera-tion in the reperfused rat brain.
基金supported by the Natural Science Foundation of Zhejiang Province(Y4110276)for financial support
文摘Pyrolysis of cyclohexane was conducted with a plug flow tube reactor in the temperature range of 873-973 K. Based on the experimental data, the mechanism and kinetic model of cyclohexane pyrolysis reaction were proposed. The kinetic analysis shows that overall conversion of cyclohexane is a first order reaction, of which the rate constant increased from 0.0086 to 0.0225 to 0.0623 s-1 with the increase of temperature from 873 to 923 to 973 K, and the apparent activation energy was determined to be 155.0±1.0 kJ mol-1. The mechanism suggests that the cyclohexane is consumed by four processes：the homolysis of C-C bond （Path I）, the homolysis of C-H bond （Path II） in reaction chain initia- tion, the H-abstraction of various radicals from the feed molecules in reaction chain propagation （Path III）, and the process associated with coke formation （Path IV）. The reaction path probability （RPP） ratio of XPath I：XPath II ： XPath III ： XPath IV was 0.5420：0.0045：0.3897：0.0638 at 873 K, and 0.4336 ： 0.0061 ： 0.4885 ： 0.0718 at 973 K, respectively.
文摘A model of burn shock was reproduced in rats and the changes of water content andmalondialdehyde(MDA)concentration in tissues were measured.The results showed that there wasa significant increase of MDA concentration and water content in lung and bumed skin post burnand a positive correlation was found between MDA level and water content.Pretreatment withsuperoxide dismutase(SOD)prevented effectively lung and skin from edema.The role of oxygen freeradicals in vascular permeability disturbance and development of edema in burns was discussed.
基金Funded by the Natural Science Foundation of Chongqing City ([2003]7974).
文摘A new series of Schiff base ligands were synthesized by the condensation of 2-amino-5-mercaptan-l,3,4-thiadiazole and salicylaldehyde or 2,4-dihydroxybenzaldehyde and their derivatives with choroacetic acid, and further reaction with corresponding metal acetate to form metal complexes. The compositions and structures of the ligands and their complexes were characterized by elemental analysis, molar conductivities, electronic absorption spectra and infra-red spectra. Their inhibition rates to free radical, such as O2, were also tested. The results show that all of the obtained complexes display significant activities, among which the copper（Ⅱ） complexes have the best inhibitive effects.
基金This paper was supported by the National "Eleven .Five" Scientific and Technological Supporting project "Test and demonstration for typical region city forest construction technol-ogy(2006BAD03A19) "
文摘The extracts from leaves of Manglietia insignis （Wall） Blume, Manglietia chingii Dandy and Manglietia yuyuanensis Law were prepared by organic solvent extraction and their components were analyzed by GC/MS and quantified. Meanwhile, the free radicals restraining activities were detected. The 21 compounds in M. insignis, 36 compounds in M. chigii and 20 compounds in M. yuyuanensis were identified. There were 11 common components in the extracts from three Manglietia species, and 12 components in two Manglietia species. The results of relative contents of every component in three extracts showed that the main constituents of M. insignis were terpenoids and alkene, amounting to 38.93%, followed by alkane （28.18%）, the nitrogen containing compounds （15.73%） and aromatic compounds （7.23 %）. The main constituents of leaf extract from M. chingii were the terpenoids and alkene, carboxylic acid, alkane and aromatic compounds, amounting to 30.22%, 14.17%, 13.87% and 13.29%, respectively, The main constituents of M. yuyuanensis were alcohol compounds, the terpenoids and alkene, and aromatic compounds, amounting to 28.00%, 25.38% and 18.00% respectively. The results showed that the three extracts had strong function of restraining oxygen free radicals. The ultra oxygen anions activity was restrained at the highest level, when the three extracts were diluted by hundred-fold, whereas the restraining capacity of hydroxyl free radicals reached maximum, when the three extracts were diluted by twenty-fold. The above results provide scientific evidences for further approaching the ecological healthy function of three MangUetia species
基金Supported partly by the National Natural Science Foundation of China(No.20042002)and the Ministry of Science and Technology of China
文摘Owing to the high oxygen-respiration in the brain of mammals, oxidative damage to prion protein hasbeen suggested to be an additional factor. A large body of intriguing features of scrapie and prion diseases haveprovided multiple lines of indirect chemistry evidence, suggesting that the infectious agents may be putative forms ofsequence-specific prion radicals (SSPR) and/or their immediate precursors in the transmissible spongiform encepha-lopathies (TSE). Here a molecular mechanism corresponding to the self-replication of scrapie protein mediated byprion free-radical processes, consonant with "protein-only" hypotheses is proposed. This new theory may not onlyaid our understanding of the occurrence of prions, but also provides new insight into the possible chemistry principlesunderlying the neurodegenerative disorders. It is anticipated that future studies based on this suggestion and chem-istry principles of genetic diseases may allow us to determine an effective approach to stop mad cow disease and itshuman version, new variant of Creutzfeldt-Jakob disease (v CJD).
文摘The inhibiting effects of CHinonin,Quercetin and Tannic Acid on the lipid oxidation (LPO) induced by irradiation were investigated by means of a modified TBA spectrophotometry.The scavenging effects of theses three active compounds on free radicals were studied by ESR technique.The results showed that antioxidation effects of Chinonin and Quercetin were better than that of Tannic Acid;though scavenging effects of the threee active compounds were similar.
文摘Objective: To investigate the effect of ultraviolet blood irradiation and oxygenation (UBIO) on the metabolism of oxygen free radicals in rabbits with acute soman intoxication. Methods: One hundred rabbits were randomly divided into 5 groups: normal control group, intoxication group, routine therapy group. UBIO therapy group and combined therapy group. After 14 d, the concentration of malondiadehyde(MDA) and activity of superoxide dismutase(SOD), glutathionperoxidase(GSH-Px), catalase (CAT) and total antioxidative capacity (T-AOC) in serum were determined respectively. Results: Compared with the normal control group, the concentration of MDA and activity of CAT in the intoxication group were significantly higher (P < 0. 05). but SOD. GSH-Px activity and T-AOC were significantly lower (P<0. 05). After UBIO or combined therapy, serum MDA level was significantly lower in comparison with intoxication group (P<0. 05). but the activity of SOD. GSH-Px, CAT and T-AOC were higher than intoxication group(P<0. 05). Conclusion: There is an obvious oxygen free radical injury in rabbits with a-cute soman intoxication. UBIO can improve the antioxidation ability of rabbits and may be applied to treat acute soman intoxication as adjunctive therapy.
文摘Recent advancements in additive manufacturing(AM)have revolutionized the design and production of complex engineering microstructures.Despite these advancements,their mathematical modeling and computational analysis remain significant challenges.This research aims to develop an effective computational method for analyzing the free vibration of functionally graded(FG)microplates under high temperatures while resting on a Pasternak foundation(PF).This formulation leverages a new thirdorder shear deformation theory(new TSDT)for improved accuracy without requiring shear correction factors.Additionally,the modified couple stress theory(MCST)is incorporated to account for sizedependent effects in microplates.The PF is characterized by two parameters including spring stiffness(k_(w))and shear layer stiffness(k_(s)).To validate the proposed method,the results obtained are compared with those of the existing literature.Furthermore,numerical examples explore the influence of various factors on the high-temperature free vibration of FG microplates.These factors include the length scale parameter(l),geometric dimensions,material properties,and the presence of the elastic foundation.The findings significantly enhance our comprehension of the free vibration of FG microplates in high thermal environments.In addition,the findings significantly enhance our comprehension of the free vibration of FG microplates in high thermal environments.In addition,the results of this research will have great potential in military and defense applications such as components of submarines,fighter aircraft,and missiles.
文摘The effects of anthocyanin from Mah,a sylvestris on plasma lipids and free radical were investigated by Reagent Kit method and in vitro assay. High tat model was set up with albino rats that were fed with different dosages of anthocyanin from Malva sylvestris 10.03 g·d^-1, 0.04 g·d ^-1 and 0.05 g·d^-1）. The results showed that the total cholesterol was decreased by 19.7% at an anthocyanin of 0.04 g. d and triglyceride was decreased by 34.4% at an anthocyanin of 0.05 g·d^-1. In vitro assay, some indexes of anthocyanin were measured including the capability of scavenging free radical, reducing force and the capability of anti-lipid peroxidation by orthophenanthroline Fe^＋2 oxidation-reduction method. The results indicated that the clearance rate of free radical reached to 43.46% when the content of anthocyanin was 0.20 mg·mL^-1 and the inhibition ratio of lipid peroxidation reached 18.82% when the content was 0.5 mg·mL^-1. Therefore anthocyanin is a kind of natural and effective free radical remover and antioxidant and can prevent from the formation of the thrombus and reduced the emergence of the cardiovascular disease.
基金supported by the National Natural Science Foundation of China (22379157,22179139)the Key Research and Development (R&D) Projects of Shanxi Province(202102040201003)+1 种基金the Research Program of Shanxi Province(202203021211203)the ICC CAS (SCJC-XCL-2023-10 and SCJC-XCL-2023-13)
文摘The chemical activation of various precursors is effective for creating additional closed pores in hard carbons for sodium storage.However,the formation mechanism of closed pores under the influence of pore-forming agents is not well understood.Herein,an effective chemical activation followed by a high-temperature self-healing strategy is employed to generate interconnected closed pores in lignin-derived hard carbon(HCs).By systematic experimental design combined with electron paramagnetic res-onance spectroscopy,it can be found that the content of free radicals in the carbon matrix influences the closure of open pores at high temperatures.Excessively high activation temperature(>700 C)leads to a low free radical concentration,making it difficult to achieve self-healing of open pores at high tempera-tures.By activation at 700°C,a balance between pore making and self-healing is achieved in the final hard carbon.A large number of free radicals triggers rapid growth and aggregation of carbon microcrys-tals,blocking pre-formed open micropores and creating additional interconnected closed pores in as-obtained hard carbons.As a result,the optimized carbon anode(LK-700-1300)delivers a high reversible capacity of 330.8 mA h g^(-1) at 0.03 A g^(-1),which is an increase of 86 mA h g^(-1) compared to the pristine lignin-derived carbon anode(L-700-1300),and exhibits a good rate performance(202.1 mA h g^(-1) at 1 A g^(-1)).This work provides a universal and effective guidance for tuning closed pores of hard carbons from otherprecursors.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11147158 and 10965002the Jiangxi-Provincial Natural Science Foundation(No 2010GQW0031)+1 种基金the Jiangxi-Provincial Scientific Research Program of the Education Bureau(No GJJ12483)the Fund Commission and Key Subject of Atomic and Molecular Physics in Jiangxi Province(2011-1015).
文摘We build a partition function model by product approximation first,then put the normal temperature calculated by moment square R^(2)/_(V),which has no rotational transition,approximately as a constant and applied to high temperature,and lastly program the compiler and compute the spectral line intensities and absorption coefficients of the 001-000 band for the hydride BH_(2) free radical molecule at several temperatures.The results show that the calculated values of total partition function agree with the data obtained from Gauss calculations and the fitted values by five factorial polynomials.Such excellent agreement has made it feasible to calculate the spectral line intensities and absorption coefficients at different temperatures.From the spectral figures at different temperatures,we find that they accord with the spectrum characteristic of asymmetric top molecules in some literature.This analysis has significance in measuring the high-temperature spectrum intensities of radical molecules by experiment.
文摘The correlation of oxygen free radical items between blood and kidney of 5/6 nephrectomy-induced chronic renal failure rats was studied. It was found that oxygen free radicals played an important role in the impairment of remnant kidney,and antioxidant vitamin E could protect remnant kidney from the impairment caused by oxygen free radicals,and that,both in normal and chronic renal failure conditions,plasma lipid peroxides and vitamin E concentration and superoxide dismutase activity of red blood cells correlated very well with corresponding items of remnant kidney.These results suggested that blood oxygen free radical items could reflect renal oxygen free radical metabolic status in chronic renal failure patients.
基金Supported by the National Natural Science Foundation of China(51109034)
文摘The structures in engineering can be simplified into elastic beams with concentrated masses and elastic spring supports. Studying the law of vibration of the beams can be a help in guiding its design and avoiding resonance. Based on the Laplace transform method, the mode shape functions and the frequency equations of the beams in the typical boundary conditions are derived. A cantilever beam with a lumped mass and a spring is selected to obtain its natural frequencies and mode shape functions. An experiment was conducted in order to get the modal parameters of the beam based on the NExT-ERA method. By comparing the analytical and experimental results, the effects of the locations of the mass and spring on the modal parameter are discussed. The variation of the natural frequencies was obtained with the changing stiffness coefficient and mass coefficient, respectively. The findings provide a reference for the vibration analysis methods and the lumped parameters layout design of elastic beams used in engineering.
