Enhancing catalytic activity of multi-enzyme in vitro through substrate channeling effect is promis-ing yet challenging.Herein,conjugated microporous polymers(CMPs)-scaffolded integrated en-zyme cascade systems(I-ECSs...Enhancing catalytic activity of multi-enzyme in vitro through substrate channeling effect is promis-ing yet challenging.Herein,conjugated microporous polymers(CMPs)-scaffolded integrated en-zyme cascade systems(I-ECSs)are constructed through co-entrapping glucose oxidase(GOx)and horseradish peroxidase(HRP),in which hydrogen peroxide(H_(2)O_(2)) is the intermediate product.The interplay of low-resistance mass transfer pathway and appropriate pore wall-H_(2)O_(2) interactions facilitates the directed transfer of H_(2)O_(2),resulting in 2.4-fold and 5.0-fold elevation in catalytic activ-ity compared to free ECSs and separated ECSs,respectively.The substrate channeling effect could be regulated by altering the mass ratio of GOx to HRP.Besides,I-ECSs demonstrate excellent stabili-ties in harsh environments and multiple recycling.展开更多
The C–H bond activation in alkane dehydrogenation reactions is a key step in determining the reaction rate.To understand the impact of entropy,we performed ab initio static and molecular dynamics free energy simulati...The C–H bond activation in alkane dehydrogenation reactions is a key step in determining the reaction rate.To understand the impact of entropy,we performed ab initio static and molecular dynamics free energy simulations of ethane dehydrogenation over Co@BEA zeolite at different temperatures.AIMD simulations showed that a sharp decrease in free energy barrier as temperature increased.Our analysis of the temperature dependence of activation free energies uncovered an unusual entropic effect accompanying the reaction.The unique spatial structures around the Co active site at different temperatures influenced both the extent of charge transfer in the transition state and the arrangement of 3d orbital energy levels.We provided explanations consistent with the principles of thermodynamics and statistical physics.The insights gained at the atomic level have offered a fresh interpretation of the intricate long-range interplay between local chemical reactions and extensive chemical environments.展开更多
In order to address the issue of sensor configuration redundancy in intelligent driving,this paper constructs a multi-objective optimization model that considers cost,coverage ability,and perception performance.And th...In order to address the issue of sensor configuration redundancy in intelligent driving,this paper constructs a multi-objective optimization model that considers cost,coverage ability,and perception performance.And then,combining a specific set of parameters,the NSGA-II algorithm is used to solve the multi-objective model established in this paper,and a Pareto front containing 24 typical configuration schemes is extracted after considering empirical constraints.Finally,using the decision preference method proposed in this paper that combines subjective and objective factors,decision scores are calculated and ranked for various configuration schemes from both cost and performance preferences.The research results indicate that the multi-objective optimization model established in this paper can screen and optimize various configuration schemes from the optimal principle of the vehicle,and the optimized configuration schemes can be quantitatively ranked to obtain the decision results for the vehicle under different preference tendencies.展开更多
Objective:To explore the effects of dopamine receptor D2(DRD2)on astrocytic dedifferentiation based on SOX2-regulated genes in neural stem cells(NSCs)and astrocytes.Methods:Immunofluorescence staining and SOX2-GFP mic...Objective:To explore the effects of dopamine receptor D2(DRD2)on astrocytic dedifferentiation based on SOX2-regulated genes in neural stem cells(NSCs)and astrocytes.Methods:Immunofluorescence staining and SOX2-GFP mice were used to examine the lineage differentiation of SOX2-positive cells during the development of cerebral cortex.Primary NSCs/astrocytes culture,ChIP-seq and Western Blot were adopted to analyze and verify the expression of candidate genes.Pharmacological manipulation,neurosphere formation,photochemical ischemia,immunofluorescence staining and behavior tests were adopted to evaluate the effects of activating DRD2 signaling on astrocytic dedifferentiation.Results:Immunofluorescence staining demonstrated the NSC-astrocyte switch of SOX2-expression in the normal development of cerebral cortex.ChIP-seq revealed enrichment of DRD2 signaling by SOX2-bound enhancers in NSCs and SOX2-bound promoters in astrocytes.Western Blot and immunofluorescence staining verified the expression of DRD2 in NSCs and reactive astrocytes.Application of quinagolide hydrocholoride(QH),an agonist of DRD2,significantly promoted astrocytic dedifferentiation both in vitro and in vivo following ischemia.In addition,quinagolide hydrocholoride treatment improved locomotion recovery.Conclusion:Activating DRD2 signaling facilitates astrocytic dedifferentiation and may be used to treat ischemic stroke.展开更多
The development of efficient nonprecious bifunctional electrocatalysts for water electrolysis is crucial to enhance the sluggish kinetics of the oxygen evolution reaction(OER)and hydrogen evolution reaction(HER).A sel...The development of efficient nonprecious bifunctional electrocatalysts for water electrolysis is crucial to enhance the sluggish kinetics of the oxygen evolution reaction(OER)and hydrogen evolution reaction(HER).A self-supporting,multiscale porous NiFeZn/NiZn-Ni catalyst with a triple interface heterojunction on nickel foam(NF)(NiFeZn/NiZn-Ni/NF)was in-situ fabricated using an electroplating-annealing-etching strategy.The unique multiinterface engineering and three-dimensional porous scaffold significantly modify the mass transport and electron interaction,resulting in superior bifunctional electrocatalytic performance for water splitting.The NiFeZn/NiZn-Ni/NF catalyst demonstrates low overpotentials of 187 m V for HER and 320 mV for OER at a current density of 600 mA/cm^(2),along with high durability over 150 h in alkaline solution.Furthermore,an electrolytic cell assembled with NiFeZn/NiZn-Ni/NF as both the cathode and anode achieves the current densities of 600 and 1000 m A/cm^(2) at cell voltages of 1.796 and 1.901 V,respectively,maintaining the high stability at 50 mA/cm^(2) for over 100 h.These findings highlight the potential of NiFeZn/NiZn-Ni/NF as a cost-effective and highly efficient bifunctional electrocatalyst for overall water splitting.展开更多
Octahedral Mn_(3)O_(4)nanoparticles with an Ag-doping and nanoporous Ag(NPS)framework was simply fabricated through an alloying-etching engineering.The dual-modified Mn_(3)O_(4)(denoted as Ag−Mn_(3)O_(4)/NPS)consists ...Octahedral Mn_(3)O_(4)nanoparticles with an Ag-doping and nanoporous Ag(NPS)framework was simply fabricated through an alloying-etching engineering.The dual-modified Mn_(3)O_(4)(denoted as Ag−Mn_(3)O_(4)/NPS)consists of Ag-doped Mn_(3)O_(4)nanoparticles crosslinked with three dimensional nanoporous Ag framework.The incorporated Ag dopant is effective in improving the intrinsic ionic and electronic conductivities of Mn_(3)O_(4),while the NPS framework is introduced to improve the electron/mass transfer across the entire electrode.Profiting from the dual-modification strategy,the Ag−Mn_(3)O_(4)/NPS exhibits admirable rate capability and cycling stability.A high reversible capacity of 88.7 mA·h/g can still be retained for over 1000 cycles at a current density of 1 A/g.Moreover,a series of ex-situ experimental techniques indicate that for Ag−Mn_(3)O_(4)/NPS electrode during the zinc ion storage,Mn_(3)O_(4)is electrochemically oxidized into various MnOx(e.g.,Mn_(2)O_(3),MnO2)species in the initial charging,and the subsequent battery reaction is actually the intercalation/deintercalation of H+and Zn2+into MnOx.展开更多
Carbonate electrolytes are one of the most desirable electrolytes for high-energy lithium-sulfur batteries(LSBs)because of their successful implementation in commercial Li-ion batteries.The low-polysulfide-solubility ...Carbonate electrolytes are one of the most desirable electrolytes for high-energy lithium-sulfur batteries(LSBs)because of their successful implementation in commercial Li-ion batteries.The low-polysulfide-solubility feature of some carbonate solvents also makes them very promising for overcoming the shuttle effects of LSBs.However,regular sulfur electrodes experience undesired electrochemical mechanisms in carbonate electrolytes due to side reactions.In this study,we report a catalytic redox mechanism of sulfur in propylene carbonate(PC)electrolyte based on a compari-son study.The catalytic mechanism is characterized by the interactions between polysulfides and dual N/O functional groups on the host carbon,which largely prevents side reactions between polysulfides and the carbonate electrolyte.Such a mechanism coupled with the low-polysulfide-solubility feature leads to stable cycling of LSBs in PC electrolyte.Favorable dual N/O functional groups are identified via a density functional theory study.This work provides an alternative route for enabling LSBs in carbonate electrolytes.展开更多
High-resolution flow field data has important applications in meteorology,aerospace engineering,high-energy physics and other fields.Experiments and numerical simulations are two main ways to obtain high-resolution fl...High-resolution flow field data has important applications in meteorology,aerospace engineering,high-energy physics and other fields.Experiments and numerical simulations are two main ways to obtain high-resolution flow field data,while the high experiment cost and computing resources for simulation hinder the specificanalysis of flow field evolution.With the development of deep learning technology,convolutional neural networks areused to achieve high-resolution reconstruction of the flow field.In this paper,an ordinary convolutional neuralnetwork and a multi-time-path convolutional neural network are established for the ablative Rayleigh-Taylorinstability.These two methods can reconstruct the high-resolution flow field in just a few seconds,and further greatlyenrich the application of high-resolution reconstruction technology in fluid instability.Compared with the ordinaryconvolutional neural network,the multi-time-path convolutional neural network model has smaller error and canrestore more details of the flow field.The influence of low-resolution flow field data obtained by the two poolingmethods on the convolutional neural networks model is also discussed.展开更多
A new Ni-based superalloy Ni48Cr28W5Co3Mn1Si1.6 was developed and the influence of a trace amount of rare earth (RE) metal addition on the oxidation resistance of this alloy was investigated. Isothermal oxidation beha...A new Ni-based superalloy Ni48Cr28W5Co3Mn1Si1.6 was developed and the influence of a trace amount of rare earth (RE) metal addition on the oxidation resistance of this alloy was investigated. Isothermal oxidation behavior was investigated at 950?1150 °C in air, and then analyzed using scanning electronic microscopy and X-ray diffraction. The results showed that oxidation mass gain kinetics of the samples with and without RE elements follow the parabolic law. The effect of 0.20% RE on oxidation resistance is relatively small, and the oxidation rate constant of the alloy modified with 0.20% RE addition decreases by 5.9%?9.0%. Oxidation at 950?1150 °C for 100 h results in the formation of MnCr2O4, Cr2O3 and SiO2. A continuous and protective MnCr2O4 spinel layer forms as outer layer. The continuous middle oxide layer is confirmed to be Cr2O3, and the innermost layer consists of discontinuous SiO2.展开更多
Eigenstructure-based coherence attributes are efficient and mature techniques for large-scale fracture detection. However, in horizontally bedded and continuous strata, buried fractures in high grayscale value zones a...Eigenstructure-based coherence attributes are efficient and mature techniques for large-scale fracture detection. However, in horizontally bedded and continuous strata, buried fractures in high grayscale value zones are difficult to detect. Furthermore, middleand small-scale fractures in fractured zones where migration image energies are usually not concentrated perfectly are also hard to detect because of the fuzzy, clouded shadows owing to low grayscale values. A new fracture enhancement method combined with histogram equalization is proposed to solve these problems. With this method, the contrast between discontinuities and background in coherence images is increased, linear structures are highlighted by stepwise adjustment of the threshold of the coherence image, and fractures are detected at different scales. Application of the method shows that it can also improve fracture cognition and accuracy.展开更多
In order to meet the requirements of combustion optimization for saving energy and reducing pollutant emission simultaneously,an immune cell subsets based multiobjective optimization algorithm(ICSMOA)is proposed.In ...In order to meet the requirements of combustion optimization for saving energy and reducing pollutant emission simultaneously,an immune cell subsets based multiobjective optimization algorithm(ICSMOA)is proposed.In the ICSMOA,the subset division operator and the immunological tolerance operation are defined.Preference can be easily addressed by using the subset division operator,and the distribution of the solutions can be guaranteed by the immunological tolerance operation.Using the ICSMOA,a group of Pareto optimal solutions can be obtained.However,by the traditional weighting method(WM),only one solution can be obtained and it cannot be judged as Pareto optimal or not.In contrast to the solutions obtained by the repeatedly performed WM,the simulation results show that most solutions obtained by the ICSMOA are better than the solutions obtained by the WM.In addition,the Pareto front obtained by the ICSMOA is not as uniform as most classical multiobjective optimization algorithms.More optimal solutions which meet the preference set by the decision-maker can be obtained and they are very useful for industrial application.展开更多
[ Objective ] The aim was to study the effects of polysaccharides of Dendrobium Huoshanense and Dendrobium moniliforme on oxygen free radicals and lipid peroxidation in vitro. [ Method] The scavenging action on .OH of...[ Objective ] The aim was to study the effects of polysaccharides of Dendrobium Huoshanense and Dendrobium moniliforme on oxygen free radicals and lipid peroxidation in vitro. [ Method] The scavenging action on .OH of polysaccharides, the inhibition action on O2^- of polysaccharides, MDA production of lipid peroxidation were measured by Fenton reaction, self oxidation system of C6H3( OH)3 and TBA method respectively. [ Result] The half scavenging concentration on ·OH of potysaccharides of Dendrobium Huoshanense and Dendrobium moniliforme was 6.79 and 6.75 mg/ml respectively. As to their half inhibition concentration on O2 , the data was 3, 04 and 3.44 mg/ml respectively. Two kinds of Dendrobium polysaccharides bothhad inhibitory actions on lipid peroxidation of liver homogenate induced by auto-oxidation and inducedoxidation, and they could alleviate oxidation damages of mice liver mitochondria induced by Vc-Fe2+ system. [Conclusion] Two kinds of Dendrobium polysacchaddes both had remarkable anti-oxidation activity in vitro.展开更多
[Objective]The aim of this study was to understand the role of polyamine oxidative degradation in the process of lettuce seed germination. [Method]After lettuce seed soaking treatments with aminoguanidine (AG,a speci...[Objective]The aim of this study was to understand the role of polyamine oxidative degradation in the process of lettuce seed germination. [Method]After lettuce seed soaking treatments with aminoguanidine (AG,a specific inhibitor of polyamine oxidases),seed germination rate,activities of polyamine oxidase (PAO) and diamine oxidase (DAO),change of endogenous polyamine and H2O2 content were determined. [Result]Compared with the control,AG treatment strongly inhibited the seed germination,which also had an extremely significant difference in seed germination rate after incubation for 12 h. During the seed germination,activities of PAO and DAO significantly changed,while their activities firstly increased and then decreased,then DAO and PAO reached peaks at 24 h and 48 h respectively. AG treatment was strongly inhibitory for activities of DAO and PAO,whose activities even disappeared after incubation with AG for 24 h and 36 h. During the seed germination,endogenous Put reduced sharply in the first 24 h,then reduced slowly in 24-60 h,while Spd decreased slowly in the early stage of germination,and then sharply declined after 48 h. However,Spm content was low but slightly increased,and the total polyamine gradually decreased. AG treatment could significantly increase endogenous polyamines,especially Put and Spd contents. During the seed germination,H2O2 content gradually increased,and had a peak from 36 to 48 h,then kept a high level at last. AG treatment could significantly reduce H2O2 content. [Conclusion]During the seed germination,the changes of endogenous polyamine and H2O2 content correspond with the changes of PAO and DAO activities,which indicate that there is an active polyamine metabolism of oxidative degradation during the lettuce seed germination.展开更多
文摘Enhancing catalytic activity of multi-enzyme in vitro through substrate channeling effect is promis-ing yet challenging.Herein,conjugated microporous polymers(CMPs)-scaffolded integrated en-zyme cascade systems(I-ECSs)are constructed through co-entrapping glucose oxidase(GOx)and horseradish peroxidase(HRP),in which hydrogen peroxide(H_(2)O_(2)) is the intermediate product.The interplay of low-resistance mass transfer pathway and appropriate pore wall-H_(2)O_(2) interactions facilitates the directed transfer of H_(2)O_(2),resulting in 2.4-fold and 5.0-fold elevation in catalytic activ-ity compared to free ECSs and separated ECSs,respectively.The substrate channeling effect could be regulated by altering the mass ratio of GOx to HRP.Besides,I-ECSs demonstrate excellent stabili-ties in harsh environments and multiple recycling.
文摘The C–H bond activation in alkane dehydrogenation reactions is a key step in determining the reaction rate.To understand the impact of entropy,we performed ab initio static and molecular dynamics free energy simulations of ethane dehydrogenation over Co@BEA zeolite at different temperatures.AIMD simulations showed that a sharp decrease in free energy barrier as temperature increased.Our analysis of the temperature dependence of activation free energies uncovered an unusual entropic effect accompanying the reaction.The unique spatial structures around the Co active site at different temperatures influenced both the extent of charge transfer in the transition state and the arrangement of 3d orbital energy levels.We provided explanations consistent with the principles of thermodynamics and statistical physics.The insights gained at the atomic level have offered a fresh interpretation of the intricate long-range interplay between local chemical reactions and extensive chemical environments.
文摘In order to address the issue of sensor configuration redundancy in intelligent driving,this paper constructs a multi-objective optimization model that considers cost,coverage ability,and perception performance.And then,combining a specific set of parameters,the NSGA-II algorithm is used to solve the multi-objective model established in this paper,and a Pareto front containing 24 typical configuration schemes is extracted after considering empirical constraints.Finally,using the decision preference method proposed in this paper that combines subjective and objective factors,decision scores are calculated and ranked for various configuration schemes from both cost and performance preferences.The research results indicate that the multi-objective optimization model established in this paper can screen and optimize various configuration schemes from the optimal principle of the vehicle,and the optimized configuration schemes can be quantitatively ranked to obtain the decision results for the vehicle under different preference tendencies.
文摘Objective:To explore the effects of dopamine receptor D2(DRD2)on astrocytic dedifferentiation based on SOX2-regulated genes in neural stem cells(NSCs)and astrocytes.Methods:Immunofluorescence staining and SOX2-GFP mice were used to examine the lineage differentiation of SOX2-positive cells during the development of cerebral cortex.Primary NSCs/astrocytes culture,ChIP-seq and Western Blot were adopted to analyze and verify the expression of candidate genes.Pharmacological manipulation,neurosphere formation,photochemical ischemia,immunofluorescence staining and behavior tests were adopted to evaluate the effects of activating DRD2 signaling on astrocytic dedifferentiation.Results:Immunofluorescence staining demonstrated the NSC-astrocyte switch of SOX2-expression in the normal development of cerebral cortex.ChIP-seq revealed enrichment of DRD2 signaling by SOX2-bound enhancers in NSCs and SOX2-bound promoters in astrocytes.Western Blot and immunofluorescence staining verified the expression of DRD2 in NSCs and reactive astrocytes.Application of quinagolide hydrocholoride(QH),an agonist of DRD2,significantly promoted astrocytic dedifferentiation both in vitro and in vivo following ischemia.In addition,quinagolide hydrocholoride treatment improved locomotion recovery.Conclusion:Activating DRD2 signaling facilitates astrocytic dedifferentiation and may be used to treat ischemic stroke.
基金financially supported from the National Natural Science Foundation of China(No.52201254)the Natural Science Foundation of Shandong Province,China(Nos.ZR2023ME155,ZR2020MB090,ZR2020QE012,ZR2020MB027)+1 种基金the Project of“20 Items of University”of Jinan,China(No.202228046)the Taishan Scholar Project of Shandong Province,China(No.tsqn202306226)。
文摘The development of efficient nonprecious bifunctional electrocatalysts for water electrolysis is crucial to enhance the sluggish kinetics of the oxygen evolution reaction(OER)and hydrogen evolution reaction(HER).A self-supporting,multiscale porous NiFeZn/NiZn-Ni catalyst with a triple interface heterojunction on nickel foam(NF)(NiFeZn/NiZn-Ni/NF)was in-situ fabricated using an electroplating-annealing-etching strategy.The unique multiinterface engineering and three-dimensional porous scaffold significantly modify the mass transport and electron interaction,resulting in superior bifunctional electrocatalytic performance for water splitting.The NiFeZn/NiZn-Ni/NF catalyst demonstrates low overpotentials of 187 m V for HER and 320 mV for OER at a current density of 600 mA/cm^(2),along with high durability over 150 h in alkaline solution.Furthermore,an electrolytic cell assembled with NiFeZn/NiZn-Ni/NF as both the cathode and anode achieves the current densities of 600 and 1000 m A/cm^(2) at cell voltages of 1.796 and 1.901 V,respectively,maintaining the high stability at 50 mA/cm^(2) for over 100 h.These findings highlight the potential of NiFeZn/NiZn-Ni/NF as a cost-effective and highly efficient bifunctional electrocatalyst for overall water splitting.
基金financially supported by the Natural Science Foundation of Shandong Province,China (Nos.ZR2023ME155,ZR2023ME085)the National Natural Science Foundation of China (No.52201254)+1 种基金the Project of“20 Items of University”of Jinan,China (No.202228046)the Taishan Scholar Project of Shandong Province,China (No.tsqn202306226)。
文摘Octahedral Mn_(3)O_(4)nanoparticles with an Ag-doping and nanoporous Ag(NPS)framework was simply fabricated through an alloying-etching engineering.The dual-modified Mn_(3)O_(4)(denoted as Ag−Mn_(3)O_(4)/NPS)consists of Ag-doped Mn_(3)O_(4)nanoparticles crosslinked with three dimensional nanoporous Ag framework.The incorporated Ag dopant is effective in improving the intrinsic ionic and electronic conductivities of Mn_(3)O_(4),while the NPS framework is introduced to improve the electron/mass transfer across the entire electrode.Profiting from the dual-modification strategy,the Ag−Mn_(3)O_(4)/NPS exhibits admirable rate capability and cycling stability.A high reversible capacity of 88.7 mA·h/g can still be retained for over 1000 cycles at a current density of 1 A/g.Moreover,a series of ex-situ experimental techniques indicate that for Ag−Mn_(3)O_(4)/NPS electrode during the zinc ion storage,Mn_(3)O_(4)is electrochemically oxidized into various MnOx(e.g.,Mn_(2)O_(3),MnO2)species in the initial charging,and the subsequent battery reaction is actually the intercalation/deintercalation of H+and Zn2+into MnOx.
文摘Carbonate electrolytes are one of the most desirable electrolytes for high-energy lithium-sulfur batteries(LSBs)because of their successful implementation in commercial Li-ion batteries.The low-polysulfide-solubility feature of some carbonate solvents also makes them very promising for overcoming the shuttle effects of LSBs.However,regular sulfur electrodes experience undesired electrochemical mechanisms in carbonate electrolytes due to side reactions.In this study,we report a catalytic redox mechanism of sulfur in propylene carbonate(PC)electrolyte based on a compari-son study.The catalytic mechanism is characterized by the interactions between polysulfides and dual N/O functional groups on the host carbon,which largely prevents side reactions between polysulfides and the carbonate electrolyte.Such a mechanism coupled with the low-polysulfide-solubility feature leads to stable cycling of LSBs in PC electrolyte.Favorable dual N/O functional groups are identified via a density functional theory study.This work provides an alternative route for enabling LSBs in carbonate electrolytes.
基金National Natural Science Foundation of China(1180500311947102+4 种基金12004005)Natural Science Foundation of Anhui Province(2008085MA162008085QA26)University Synergy Innovation Program of Anhui Province(GXXT-2022-039)State Key Laboratory of Advanced Electromagnetic Technology(Grant No.AET 2024KF006)。
文摘High-resolution flow field data has important applications in meteorology,aerospace engineering,high-energy physics and other fields.Experiments and numerical simulations are two main ways to obtain high-resolution flow field data,while the high experiment cost and computing resources for simulation hinder the specificanalysis of flow field evolution.With the development of deep learning technology,convolutional neural networks areused to achieve high-resolution reconstruction of the flow field.In this paper,an ordinary convolutional neuralnetwork and a multi-time-path convolutional neural network are established for the ablative Rayleigh-Taylorinstability.These two methods can reconstruct the high-resolution flow field in just a few seconds,and further greatlyenrich the application of high-resolution reconstruction technology in fluid instability.Compared with the ordinaryconvolutional neural network,the multi-time-path convolutional neural network model has smaller error and canrestore more details of the flow field.The influence of low-resolution flow field data obtained by the two poolingmethods on the convolutional neural networks model is also discussed.
基金funded by the foundation of HUST-WISCO Joint Laboratory
文摘A new Ni-based superalloy Ni48Cr28W5Co3Mn1Si1.6 was developed and the influence of a trace amount of rare earth (RE) metal addition on the oxidation resistance of this alloy was investigated. Isothermal oxidation behavior was investigated at 950?1150 °C in air, and then analyzed using scanning electronic microscopy and X-ray diffraction. The results showed that oxidation mass gain kinetics of the samples with and without RE elements follow the parabolic law. The effect of 0.20% RE on oxidation resistance is relatively small, and the oxidation rate constant of the alloy modified with 0.20% RE addition decreases by 5.9%?9.0%. Oxidation at 950?1150 °C for 100 h results in the formation of MnCr2O4, Cr2O3 and SiO2. A continuous and protective MnCr2O4 spinel layer forms as outer layer. The continuous middle oxide layer is confirmed to be Cr2O3, and the innermost layer consists of discontinuous SiO2.
基金sponsored by the National Science&Technology Major Special Project(Grant No.2011ZX05025-001-04)
文摘Eigenstructure-based coherence attributes are efficient and mature techniques for large-scale fracture detection. However, in horizontally bedded and continuous strata, buried fractures in high grayscale value zones are difficult to detect. Furthermore, middleand small-scale fractures in fractured zones where migration image energies are usually not concentrated perfectly are also hard to detect because of the fuzzy, clouded shadows owing to low grayscale values. A new fracture enhancement method combined with histogram equalization is proposed to solve these problems. With this method, the contrast between discontinuities and background in coherence images is increased, linear structures are highlighted by stepwise adjustment of the threshold of the coherence image, and fractures are detected at different scales. Application of the method shows that it can also improve fracture cognition and accuracy.
基金The National Natural Science Foundation of China(No.51036002,51076027)the Key Project of Ministry of Education of China(No.108060)
文摘In order to meet the requirements of combustion optimization for saving energy and reducing pollutant emission simultaneously,an immune cell subsets based multiobjective optimization algorithm(ICSMOA)is proposed.In the ICSMOA,the subset division operator and the immunological tolerance operation are defined.Preference can be easily addressed by using the subset division operator,and the distribution of the solutions can be guaranteed by the immunological tolerance operation.Using the ICSMOA,a group of Pareto optimal solutions can be obtained.However,by the traditional weighting method(WM),only one solution can be obtained and it cannot be judged as Pareto optimal or not.In contrast to the solutions obtained by the repeatedly performed WM,the simulation results show that most solutions obtained by the ICSMOA are better than the solutions obtained by the WM.In addition,the Pareto front obtained by the ICSMOA is not as uniform as most classical multiobjective optimization algorithms.More optimal solutions which meet the preference set by the decision-maker can be obtained and they are very useful for industrial application.
文摘[ Objective ] The aim was to study the effects of polysaccharides of Dendrobium Huoshanense and Dendrobium moniliforme on oxygen free radicals and lipid peroxidation in vitro. [ Method] The scavenging action on .OH of polysaccharides, the inhibition action on O2^- of polysaccharides, MDA production of lipid peroxidation were measured by Fenton reaction, self oxidation system of C6H3( OH)3 and TBA method respectively. [ Result] The half scavenging concentration on ·OH of potysaccharides of Dendrobium Huoshanense and Dendrobium moniliforme was 6.79 and 6.75 mg/ml respectively. As to their half inhibition concentration on O2 , the data was 3, 04 and 3.44 mg/ml respectively. Two kinds of Dendrobium polysaccharides bothhad inhibitory actions on lipid peroxidation of liver homogenate induced by auto-oxidation and inducedoxidation, and they could alleviate oxidation damages of mice liver mitochondria induced by Vc-Fe2+ system. [Conclusion] Two kinds of Dendrobium polysacchaddes both had remarkable anti-oxidation activity in vitro.
基金Supported by Doctorate Fund of Suzhou University (13120740)~~
文摘[Objective]The aim of this study was to understand the role of polyamine oxidative degradation in the process of lettuce seed germination. [Method]After lettuce seed soaking treatments with aminoguanidine (AG,a specific inhibitor of polyamine oxidases),seed germination rate,activities of polyamine oxidase (PAO) and diamine oxidase (DAO),change of endogenous polyamine and H2O2 content were determined. [Result]Compared with the control,AG treatment strongly inhibited the seed germination,which also had an extremely significant difference in seed germination rate after incubation for 12 h. During the seed germination,activities of PAO and DAO significantly changed,while their activities firstly increased and then decreased,then DAO and PAO reached peaks at 24 h and 48 h respectively. AG treatment was strongly inhibitory for activities of DAO and PAO,whose activities even disappeared after incubation with AG for 24 h and 36 h. During the seed germination,endogenous Put reduced sharply in the first 24 h,then reduced slowly in 24-60 h,while Spd decreased slowly in the early stage of germination,and then sharply declined after 48 h. However,Spm content was low but slightly increased,and the total polyamine gradually decreased. AG treatment could significantly increase endogenous polyamines,especially Put and Spd contents. During the seed germination,H2O2 content gradually increased,and had a peak from 36 to 48 h,then kept a high level at last. AG treatment could significantly reduce H2O2 content. [Conclusion]During the seed germination,the changes of endogenous polyamine and H2O2 content correspond with the changes of PAO and DAO activities,which indicate that there is an active polyamine metabolism of oxidative degradation during the lettuce seed germination.