This paper explores the application and effect evaluation of corpus linguistics in English teaching.It first introduces the basic concepts and development history of corpus linguistics,then analyzes its connection wit...This paper explores the application and effect evaluation of corpus linguistics in English teaching.It first introduces the basic concepts and development history of corpus linguistics,then analyzes its connection with language teaching theories,discussing the advantages and challenges of using corpora in language teaching.Next,it delves into the methods and technologies for building and utilizing corpora,as well as their role in developing teaching resources.Lastly,within the framework and methods of teaching effect evaluation,specific application cases of corpus linguistics in teaching design are analyzed,and their effects are assessed.Recommendations for teaching improvement and future development directions are also proposed.展开更多
Through the establishment of music teaching effect evaluation model and the multimedia courseware evaluation model, which can effectively avoid the influence of subjective evaluation, the evaluation process will be si...Through the establishment of music teaching effect evaluation model and the multimedia courseware evaluation model, which can effectively avoid the influence of subjective evaluation, the evaluation process will be simple and objective. Through the issuance of assessment questionnaire, each index is divided into four grades of excellent, good, poor, according to percentile scoring, the score of every index multiply corresponding weight, and then addition, and finally we can obtain the evaluation results.展开更多
[Objectives]This study was conducted to explore the optimization of ultrasonic-assisted organic solvent extraction of pomegranate peel polyphenols(PPPs),and to study the protective effect of PPPs on acute alcoholic li...[Objectives]This study was conducted to explore the optimization of ultrasonic-assisted organic solvent extraction of pomegranate peel polyphenols(PPPs),and to study the protective effect of PPPs on acute alcoholic liver injury in mice.[Methods]The optimal extraction conditions of PPPs were determined by single factor and orthogonal experiments,and an acute alcoholic liver injury model in mice was established.Bifendate was used as the positive control group to investigate the protective effect of low,medium and high doses of PPPs on acute alcoholic liver injury.[Results]The optimum extraction process parameters were followed as 60%ethanol concentration,solid-liquid ratio of 1:40(w/v),extraction temperature of 50℃,and extraction time of 1.5 h,and the yield was 1.42%.The results of animal experiments showed that PPPs could effectively reduce the degree of alcoholic liver injury in mice,reduce the levels of serum alanine aminotransferase(ALT)and aspartate aminotransferase(AST),and reduce the inflammation and necrosis of liver tissue in mice.Meanwhile,the total polyphenols from pomegranate peel also significantly reduced the expression levels of malondialdehyde(MDA),tumor necrosis factor(TNF-α)and interleukin-6(IL-6)in mice,and increased the levels of superoxide dismutase(SOD)and reduced glutathione(GSH)in liver tissue of mice,indicating its antioxidant and anti-inflammatory effects,further illustrating its protective effect on alcoholic liver injury.[Conclusions]PPPs could reduce the expression levels of TNF-α,IL-6 and MDA in mice,and increase the expression levels of SOD and GSH to achieve the protective effect on acute alcoholic liver injury in mice.This study will provide new ideas for the development of new anti-alcoholic liver injury drug resources.展开更多
[Objectives]Optimum extraction conditions of total flavonoids from Fructus Aurantii Immaturus(TFFAI)and its resistance activity to ultraviolet radiation were investigated in present research.[Methods]The optimal extra...[Objectives]Optimum extraction conditions of total flavonoids from Fructus Aurantii Immaturus(TFFAI)and its resistance activity to ultraviolet radiation were investigated in present research.[Methods]The optimal extraction conditions of TFFAI were determined by single factor and orthogonal experiments,and the survival rate of TFFAI on HaCaT cells irradiated with UVB rays was investigated.It s antioxidant capacity was determined by ABTS.[Results]The results showed that the highest yield of TFFAI was obtained with 70%ethanol at a solid-to-liquid ratio of 1:50(w/v)and 40℃for 1.5 h by single-factor and orthogonal experiments.Total flavonoids(0.25-1.00 mg/ml)could significantly improve the survival rate of HaCaT cell line.Meanwhile,the maximum absorption peak of TFFAI was found at 283 nm,and in-vitro antioxidant experiment identified that TFFAI had a good clearance rate to ABTS.It suggestes that TFFAI could protect the cells from UVB damage by absorption of UVB rays and anti-oxidation.[Conclusions]TFFAI played a protective role on UVB irradiated cells through UVB ultraviolet absorption and antioxidant pathways.展开更多
Antioxidant andα-glucosidase inhibitiory active compounds of Cercis chinensis flowers were investigated with bio-assay guiding method.Ethyl acetate fraction(CLEa)and n-butanol fraction(CLBu)exhibited antioxidant and...Antioxidant andα-glucosidase inhibitiory active compounds of Cercis chinensis flowers were investigated with bio-assay guiding method.Ethyl acetate fraction(CLEa)and n-butanol fraction(CLBu)exhibited antioxidant andα-glucosidase inhibitiory activity in vitro,and the corresponding active fractions,EaFr.3,EaFr.5 and BuFr.1,exhibited higher antioxidant andα-glucosidase inhibitiory activity than those of other fractions.Eight compounds,ethyl gallate(1),stearic acid(2),docosanoic acid(3),5α-stigmast-9(11)-en-3β-ol(4),kaempferol-3-O-α-rhamnopyranoside(5),vanillic acid(6),fisetin(7),andβ-sitosterol(8),were isolated and identified from CLEa and CLBu.Ethyl gallate shown the highest antioxidant activity by scavenging DPPH radical and reducing ferric compared.Docosanoic acid and vanillic acid shown strongerα-glucosidase inhibitory activity than that of acarbose.展开更多
The thermal decomposition process was studied by the TG–DTA analyzer. The results show that the decomposition process of sodium hydroxyethyl sulfonate consisted of three stages: the mass loss for the first, the secon...The thermal decomposition process was studied by the TG–DTA analyzer. The results show that the decomposition process of sodium hydroxyethyl sulfonate consisted of three stages: the mass loss for the first, the second and third stages may be about the groups of CH_3CH_2OH, CH_3CHO and SO_2 volatilized, respectively. The decomposition residuum of three stages was analyzed by FT-IR, and the results of FT-IR agreed with the decomposition process predicted by theoretical weight loss. The specific heat capacity of sodium hydroxyethyl sulfonate was determined by differential scanning calorimetry(DSC). The melting temperature and melting enthalpy were obtained to be 465.41 K and 25.69 kJ·mol^(-1), respectively. The molar specific heat capacity of sodium hydroxyethyl sulfonate was determinated from 310.15 K to 365.15 K and expressed as a function of temperature.展开更多
High performance of lithium-sulfur batteries have been dragged down by their shuttling behavior which is complicated multiphase transition-based 16-electron redox reactions of the S8/Li2 S.In this article,the triple-p...High performance of lithium-sulfur batteries have been dragged down by their shuttling behavior which is complicated multiphase transition-based 16-electron redox reactions of the S8/Li2 S.In this article,the triple-phase interfaces of graphene-like carbon clusters on antimony trisulfide(C-Sb_(2)S_(3))nanowires are tailored to design a multifunctional polysulfide host which can inhibit migration of polysulfides and accelerate conversion kinetics of redox electrochemical reactions.Benefiting from the triple-interface design of polysulfides/Sb_(2)S_(3)/carbon clusters,the C-Sb_(2)S_(3) electrode not only anchors polysulfide migration by the synergistic effect of Sb,S,and C atoms as interfacial active sites,but also the graphene-like carbon clusters shorten the diffusion paths to further favor redox electron/ion transport through the liquid(electrolyte/polysulfide)and solid(Li2 S/S8,carbon clusters,and Sb_(2)S_(3))-based triple-phases.Therefore,these Li_(2)S_(6)-based C-Sb_(2)S_(3) cells possess high sulfur loading,excellent cycling stability,impressive specific capacity,and great rate capability.This work of interfacial engineering reveals insight for powering reaction kinetics in the complicated multistep catalysis reaction with multiphase evolution-based chargetransfer/non-transfer processes.展开更多
The thermal stability of Ti@A1 core/shell nanoparticles with different sizes and components during continuous heating and cooling processes is examined by a molecular dynamics simulation with embedded atom method. The...The thermal stability of Ti@A1 core/shell nanoparticles with different sizes and components during continuous heating and cooling processes is examined by a molecular dynamics simulation with embedded atom method. The thermodynamic properties and structure evolution during continuous heating and cooling processes are investigated through the character- ization of the potential energy, specific heat distribution, and radial distribution function (RDF). Our study shows that, for fixed Ti core size, the melting temperature decreases with A1 shell thickness, while the crystallizing temperature and glass formation temperature increase with A1 shell thickness. Diverse melting mechanisms have been discovered for different Ti core sized with fixed A1 shell thickness nanoparticles. The melting temperature increases with the Ti core radius. The trend agrees well with the theoretical phase diagram of bimetallic nanoparticles. In addition, the glass phase formation of A1-Ti nanoparticles for the fast cooling rate of 12 K/ps, and the crystal phase formation for the low cooling rate of 0.15 K/ps. The icosahedron structure is formed in the frozen 4366 A1-Ti atoms for the low cooling rate.展开更多
The purpose of the study is to implement a new model based on the Navier-Stokes equations for the characterization of landslide sediments interacting with a moving fluid.The model is implemented by combining Hypermesh...The purpose of the study is to implement a new model based on the Navier-Stokes equations for the characterization of landslide sediments interacting with a moving fluid.The model is implemented by combining Hypermesh,the LS-DYNA software and MATLAB.The results show that the main factors affecting the permeability of landslide sediments are the genetic mechanism,the structure and composition of materials,material lithology,and stress.The characteristics and mechanism of permeability changes are determined by adjusting the water levels of fluids.It is found that the permeability of landslide sediments increases at the front and decreases in the middle and at the rear of the considered domain.The magnitude of the internal flow for the whole system decreases first and then increases with a change in the water level during seepage.展开更多
This paper reports the detailed preparation and phosphorescence properties of Eu2+-activated Ca2ZnSi2O7 phosphors by a modified solid-state reaction.Phase-pure crystalline Ca2ZnSi2O7 is obtained at 600℃,a much lower ...This paper reports the detailed preparation and phosphorescence properties of Eu2+-activated Ca2ZnSi2O7 phosphors by a modified solid-state reaction.Phase-pure crystalline Ca2ZnSi2O7 is obtained at 600℃,a much lower temperature than by conventional solid-state reaction and the preparation process of Ca2ZnSi2O7 is simple.The obtained phosphors showed three emission peaks at 480,580 and 620 nm,respectively.Auxiliary activator R3+(R=Dy,Nd,Tm) would enhance their luminescent properties.展开更多
Chinese martial arts have a long history, profound, which is an integral part of Chinese traditional culture of grandeur. China joined the WTO and the Beijing Olympic Games "has a rich cultural heritage of thousands ...Chinese martial arts have a long history, profound, which is an integral part of Chinese traditional culture of grandeur. China joined the WTO and the Beijing Olympic Games "has a rich cultural heritage of thousands of years of Chinese martial arts with its unique charm and much of the world' s attention." In the face of opportunities and challenges, the international spread of martial arts has become an irresistible trend. "First of propagation, the spread of the concept of martial arts and martial arts were defined international spread, and it were explains martial international spread of cultural level societal level and significance of the economic level, dialectical judge the outcome of the international transmission acquired with the problems." Secondly, the traditional martial arts culture for martial international dissemination presented aphasia phenomenon, by means of the analysis of the advanced nature of martial arts culture, the martial arts and cultural heritage considered as the center of gravity advantages, not only to absorb the multicultural essence of martial arts culture useful, but also highlight the ethnic characteristics of martial arts culture, martial arts culture to enhance capacity external radiation, the Chinese martial arts as a complete all- round cultural forms, multi-level, multi-an^le display, promote the Chinese martial arts to the world in a more in-depth. "展开更多
In the US and British literature, there are many works using China or the Chinese people as depict objects. With the development of American and British literature, the shape of the image of China is diverse. Currentl...In the US and British literature, there are many works using China or the Chinese people as depict objects. With the development of American and British literature, the shape of the image of China is diverse. Currently, the research of the image of China or Chinese people in the US and British literature has yielded fruitful results, the majority concentrated on the study before the new century writers and representative works. In the new century, the causes and significance of the image of China and the Chinese people in American literature have the positive impact on self-awareness and self-construction of the China' s image.展开更多
Multidimensional Scale Evaluation Rules as a performer in the field of learning assessment is feasible, but for each dimension settings, level settings and value setting need to be developed according to the actual ra...Multidimensional Scale Evaluation Rules as a performer in the field of learning assessment is feasible, but for each dimension settings, level settings and value setting need to be developed according to the actual raters, object evaluation, the focus of the evaluation. Scores of overall dimensions use variance analysis, and the results show a significant difference. In sub-dimension score comparison, the high group and low group both got higher scores in the degree of difficulty performing works and read music accuracy. The high group and low group are different on dimensions of the lowest score. Total scores in the scale of multi-dimensional evaluation of rules are positively correlated on the scores on the improvising horizontal dimension, but the correlation is not very high level, that is not all students who is better in playing levels, and they can get higher scores on the improvising horizontal dimension. Using multi-dimensional scale scores and teacher direct evaluation rules score are significantly different for student achievement.展开更多
The distance effect of the doped heteroatoms away from the catalytic centers has rarely been reported.In this work,we conducted density functional theory calculations to thoroughly investigate the influence of heteroa...The distance effect of the doped heteroatoms away from the catalytic centers has rarely been reported.In this work,we conducted density functional theory calculations to thoroughly investigate the influence of heteroatom(N,P,B,and S atoms)doping distance on the oxygen reduction reaction(ORR)activity of graphene-based FeN_(4)sites.We uncovered a Sabatier-like relationship between heteroatom doping distance and ORR activity of FeN_(4)sites.The nearest doping does not significantly improve and even block the ORR activity of FeN_(4)sites.Optimal ORR activity is achieved when the heteroatoms are 4-5Å(N,P,and S atoms)or 6-7Å(B atoms)away from the Fe atoms.Analysis of electronic structure indicates that distance effect can modulate the local chemical environment of Fe atoms,thereby account for the changes in ORR activity along with the doping distance and doping atoms.This study provides insights into the influence of heteroatom doping on the chemical environment of reaction active centers,and provides the theoretical guidance for controlling the doping distance of heteroatoms to achieve optimal catalytic activity and selectivity.展开更多
Developing stable electrodes for seawater splitting remains a great challenge due to the detachment of catalysts at a large operating current and severe anode corrosion caused by chlorine.Herein,divalent anion interca...Developing stable electrodes for seawater splitting remains a great challenge due to the detachment of catalysts at a large operating current and severe anode corrosion caused by chlorine.Herein,divalent anion intercalation and etching-hydrolysis strategies are deployed to synthesize the ultra-stable anode,dendritic Fe(OH)_(3) grown on Ni(SO_4)_(0.3)(OH)_(1.4)–Ni(OH)_(2).Experimental results reveal that the anode exhibits good activity and excellent stability in alkaline simulated seawater.After 500 h,the current density operated at 1.72 V remains 99.5%,about 210 m A cm^(-2).The outstanding stability originates from the etchinghydrolysis strategy,which strengthens the interaction between the catalyst and the carrier and retards thus the detachment of catalysts at a large current density.Besides,theoretical simulations confirm that the intercalated divalent anions,such as SO_4^(2-) and CO_(3)^(2-),can weaken the adsorption strength of chlorine on the surface of catalysts and hinder the coupling and hybridization between chlorine and nickel,which slows down the anode corrosion and improves catalytic stability.Furthermore,the twoelectrode system shows the remarkable 95.1% energy efficiency at 2,000 A m-2and outstanding stability in 6 mol L^(-1) KOH +seawater at 80 ℃.展开更多
The lithium-sulfur battery has attracted enormous attention as being one of the most significant energy storage technologies due to its high energy density and cost-effectiveness.However,the "shuttle effect"...The lithium-sulfur battery has attracted enormous attention as being one of the most significant energy storage technologies due to its high energy density and cost-effectiveness.However,the "shuttle effect" of polysulfide intermediates represents a formidable challenge towards its wide applications.Herein,we have designed and synthesized two-dimensional Cu,Zn and Sn-based multimetallic sulfide nanosheets to construct multi-active sites for the immobilization and entrapment of polysulfides with offering better performance in liquid Li2S6-based lithium-polysulfide batteries.Both experimental measurements and theoretical computations demonstrate that the interfacial multi-active sites of multimetallic sulfides not only accelerate the multi-chained redox reactions of highly diffusible polysulfides,but also strengthen affinities toward polysulfides.By adopting multimetallic sulfide nanosheets as the sulfur host,the liquid Li2 S6-based cell exhibits an impressive rate capability with 1200 mAh/g and retains 580 mAh/g at 0.5 mA/cm^(2) after 1000 cycles.With high sulfur mass loading conditions,the cell with 2.0 mg/cm^(2) sulfur loading delivers a cell capacity of 1068 mAh/g and maintains 480 mAh/g with 0.8 mA/cm^(2) and 500 cycles.This study provides new insights into the multifunctional material design with multi-active sites for elevated lithium-polysulfide batteries.展开更多
Objective:α-Glucosidase inhibitors can be used as a new class of antidiabetic drug.By competitively inhibiting glycosidase activity,these inhibitors help to prevent the fast breakdown of sugars and thereby control th...Objective:α-Glucosidase inhibitors can be used as a new class of antidiabetic drug.By competitively inhibiting glycosidase activity,these inhibitors help to prevent the fast breakdown of sugars and thereby control the blood sugar level.This study provides a wealth of information aboutα-glucosidase inhibitors isolated from medicinal plants;this knowledge will be useful in finding more potent antidiabetic candidates from the natural resources for the clinical development of antidiabetic therapeutics.Results:411 compounds exhibitingα-glucosidase inhibitory activity were summarized and isolated them from medicinal plants.The compound classes isolated include:terpenes(61)from 14 genus,alkaloids(37)from 11 genus,quinines(49)from 4 genus,flavonoids(103)from 24 genus,phenols(37)from 9 genus,phenylpropanoids(73)from 20 genus,sterides(8)from 5 genus,and other types of compounds(43).Conclusion:Compounds withα-glucosidase inhibitory activity are abundant in nature and can be obtained from several sources.They have highα-glucosidase inhibitory potential,and can be clinically developed for treating diabetes mellitus.展开更多
Cordyceps militaris,belongs to Clavicipitaceae family,was investigated for its chemical compounds,and six compounds were isolated and purified by silica gel column chromatography,Sephadex LH-20 and recrystallization,a...Cordyceps militaris,belongs to Clavicipitaceae family,was investigated for its chemical compounds,and six compounds were isolated and purified by silica gel column chromatography,Sephadex LH-20 and recrystallization,and their structures were elucidated by spectral techniques and physicochemical properties as ergosterol(1),adenosine(2),cordycepin(3),ergosterol peroxide(4),tetracosanoic acid 2,3-dihydroxypropylester(5),mannitol(6).Procoagulant activity was screened by assaying the activated partial thromboplastin time(APTT),prothrombin time(PT),thrombin time(TT)and fibrinogen(FIB)in vitro.The results indicated that ergosterol,adenosine,cordycepin,ergosterol peroxide and mannitol showed strong procoagulant activity.展开更多
The mechanical properties of magnesium alloys at both ambient and elevated temperatures can be improved with the existence of Mg2Si phase in the matrix.However,these properties can be deteriorated if the Mg2Si phase i...The mechanical properties of magnesium alloys at both ambient and elevated temperatures can be improved with the existence of Mg2Si phase in the matrix.However,these properties can be deteriorated if the Mg2Si phase is of coarse Chinese script type.Effects of the silicocalcium addition on the microstructure and properties of an Mg-6Al-0.5Mn alloy(AM60)were studied.The microstructure of the alloy with the addition of silicocalcium is featured with dispersedly distributed small polygonal type Mg2Si phases.The microhardness,tensile strength,percentage elongation and toughness of as-cast AM60+1.0Si-Ca alloy are 20%,13.3%,28.5% and 50% higher than these of AM60 alloy respectively.Further corrosion measurements showed that the silicocalcium-modified AM60 alloy increases the corrosion potential by 0.04V and decreases the lost weight corrosion rate by 45%.展开更多
This paper investigates the thermal performance of prefabricated exterior walls using the Computational Fluid Dynamics method to reduce energy consumption.The thermal performance of the prefabricated exterior wall was...This paper investigates the thermal performance of prefabricated exterior walls using the Computational Fluid Dynamics method to reduce energy consumption.The thermal performance of the prefabricated exterior wall was numerically simulated using the software ANSYS Fluent.The composite wall containing the cavity is taken as the research object in this paper after analysis.The simulation suggests that when the cavity thickness is 20 mm and 30 mm,the heat transfer coefficient of the air-sandwich wall is 1.3 and 1.29,respectively.Therefore,the optimal width of the cavity is 20 mm,and the most suitable material is the aerated concrete block.In addition,a comparative analysis is conducted on the cavity temperature in the wall under different conditions.It is proven that an intelligent environment control system can significantly improve thermal efficiency and provide a solid theoretical basis for further research in the external insulation of prefabricated buildings.展开更多
文摘This paper explores the application and effect evaluation of corpus linguistics in English teaching.It first introduces the basic concepts and development history of corpus linguistics,then analyzes its connection with language teaching theories,discussing the advantages and challenges of using corpora in language teaching.Next,it delves into the methods and technologies for building and utilizing corpora,as well as their role in developing teaching resources.Lastly,within the framework and methods of teaching effect evaluation,specific application cases of corpus linguistics in teaching design are analyzed,and their effects are assessed.Recommendations for teaching improvement and future development directions are also proposed.
文摘Through the establishment of music teaching effect evaluation model and the multimedia courseware evaluation model, which can effectively avoid the influence of subjective evaluation, the evaluation process will be simple and objective. Through the issuance of assessment questionnaire, each index is divided into four grades of excellent, good, poor, according to percentile scoring, the score of every index multiply corresponding weight, and then addition, and finally we can obtain the evaluation results.
基金Supported by Provincial Key College Students Innovation and Entrepreneurship Training Program Project (202211834033).
文摘[Objectives]This study was conducted to explore the optimization of ultrasonic-assisted organic solvent extraction of pomegranate peel polyphenols(PPPs),and to study the protective effect of PPPs on acute alcoholic liver injury in mice.[Methods]The optimal extraction conditions of PPPs were determined by single factor and orthogonal experiments,and an acute alcoholic liver injury model in mice was established.Bifendate was used as the positive control group to investigate the protective effect of low,medium and high doses of PPPs on acute alcoholic liver injury.[Results]The optimum extraction process parameters were followed as 60%ethanol concentration,solid-liquid ratio of 1:40(w/v),extraction temperature of 50℃,and extraction time of 1.5 h,and the yield was 1.42%.The results of animal experiments showed that PPPs could effectively reduce the degree of alcoholic liver injury in mice,reduce the levels of serum alanine aminotransferase(ALT)and aspartate aminotransferase(AST),and reduce the inflammation and necrosis of liver tissue in mice.Meanwhile,the total polyphenols from pomegranate peel also significantly reduced the expression levels of malondialdehyde(MDA),tumor necrosis factor(TNF-α)and interleukin-6(IL-6)in mice,and increased the levels of superoxide dismutase(SOD)and reduced glutathione(GSH)in liver tissue of mice,indicating its antioxidant and anti-inflammatory effects,further illustrating its protective effect on alcoholic liver injury.[Conclusions]PPPs could reduce the expression levels of TNF-α,IL-6 and MDA in mice,and increase the expression levels of SOD and GSH to achieve the protective effect on acute alcoholic liver injury in mice.This study will provide new ideas for the development of new anti-alcoholic liver injury drug resources.
基金Supported by National Key Program of Innovation and Entrepreneurship Training for College Students (202211834021)Project Funds of Zhengzhou Science and Technology Bureau (ZZSZX202109).
文摘[Objectives]Optimum extraction conditions of total flavonoids from Fructus Aurantii Immaturus(TFFAI)and its resistance activity to ultraviolet radiation were investigated in present research.[Methods]The optimal extraction conditions of TFFAI were determined by single factor and orthogonal experiments,and the survival rate of TFFAI on HaCaT cells irradiated with UVB rays was investigated.It s antioxidant capacity was determined by ABTS.[Results]The results showed that the highest yield of TFFAI was obtained with 70%ethanol at a solid-to-liquid ratio of 1:50(w/v)and 40℃for 1.5 h by single-factor and orthogonal experiments.Total flavonoids(0.25-1.00 mg/ml)could significantly improve the survival rate of HaCaT cell line.Meanwhile,the maximum absorption peak of TFFAI was found at 283 nm,and in-vitro antioxidant experiment identified that TFFAI had a good clearance rate to ABTS.It suggestes that TFFAI could protect the cells from UVB damage by absorption of UVB rays and anti-oxidation.[Conclusions]TFFAI played a protective role on UVB irradiated cells through UVB ultraviolet absorption and antioxidant pathways.
基金This work was supported by Key Project in Science and Technology Agency of Henan Province(192102110112,192102110214 and 182102410083)Innovation Training Program for College Students(201910475107 and MSCXSY2019036).
文摘Antioxidant andα-glucosidase inhibitiory active compounds of Cercis chinensis flowers were investigated with bio-assay guiding method.Ethyl acetate fraction(CLEa)and n-butanol fraction(CLBu)exhibited antioxidant andα-glucosidase inhibitiory activity in vitro,and the corresponding active fractions,EaFr.3,EaFr.5 and BuFr.1,exhibited higher antioxidant andα-glucosidase inhibitiory activity than those of other fractions.Eight compounds,ethyl gallate(1),stearic acid(2),docosanoic acid(3),5α-stigmast-9(11)-en-3β-ol(4),kaempferol-3-O-α-rhamnopyranoside(5),vanillic acid(6),fisetin(7),andβ-sitosterol(8),were isolated and identified from CLEa and CLBu.Ethyl gallate shown the highest antioxidant activity by scavenging DPPH radical and reducing ferric compared.Docosanoic acid and vanillic acid shown strongerα-glucosidase inhibitory activity than that of acarbose.
文摘The thermal decomposition process was studied by the TG–DTA analyzer. The results show that the decomposition process of sodium hydroxyethyl sulfonate consisted of three stages: the mass loss for the first, the second and third stages may be about the groups of CH_3CH_2OH, CH_3CHO and SO_2 volatilized, respectively. The decomposition residuum of three stages was analyzed by FT-IR, and the results of FT-IR agreed with the decomposition process predicted by theoretical weight loss. The specific heat capacity of sodium hydroxyethyl sulfonate was determined by differential scanning calorimetry(DSC). The melting temperature and melting enthalpy were obtained to be 465.41 K and 25.69 kJ·mol^(-1), respectively. The molar specific heat capacity of sodium hydroxyethyl sulfonate was determinated from 310.15 K to 365.15 K and expressed as a function of temperature.
基金supported by the National Natural Science Foundation of China(Grant No.61904080)the Natural Science Foundation of Jiangsu Province(Grant No.BK20190670)+1 种基金the Natural Science Foundation of Colleges and Universities in Jiangsu Province(Grant No.19KJB530008)the Technology Innovation Project for Overseas Scholar in Nanjing,the Start-up Foundation of Nanjing Tech University。
文摘High performance of lithium-sulfur batteries have been dragged down by their shuttling behavior which is complicated multiphase transition-based 16-electron redox reactions of the S8/Li2 S.In this article,the triple-phase interfaces of graphene-like carbon clusters on antimony trisulfide(C-Sb_(2)S_(3))nanowires are tailored to design a multifunctional polysulfide host which can inhibit migration of polysulfides and accelerate conversion kinetics of redox electrochemical reactions.Benefiting from the triple-interface design of polysulfides/Sb_(2)S_(3)/carbon clusters,the C-Sb_(2)S_(3) electrode not only anchors polysulfide migration by the synergistic effect of Sb,S,and C atoms as interfacial active sites,but also the graphene-like carbon clusters shorten the diffusion paths to further favor redox electron/ion transport through the liquid(electrolyte/polysulfide)and solid(Li2 S/S8,carbon clusters,and Sb_(2)S_(3))-based triple-phases.Therefore,these Li_(2)S_(6)-based C-Sb_(2)S_(3) cells possess high sulfur loading,excellent cycling stability,impressive specific capacity,and great rate capability.This work of interfacial engineering reveals insight for powering reaction kinetics in the complicated multistep catalysis reaction with multiphase evolution-based chargetransfer/non-transfer processes.
基金Project supported by the National Natural Science Foundation of China(Grant No.21401064)the Science&Technology Development Program of Henan Province,China(Grant No.142300410282)the Program of Henan Educational Committee,China(Grant No.13B140986)
文摘The thermal stability of Ti@A1 core/shell nanoparticles with different sizes and components during continuous heating and cooling processes is examined by a molecular dynamics simulation with embedded atom method. The thermodynamic properties and structure evolution during continuous heating and cooling processes are investigated through the character- ization of the potential energy, specific heat distribution, and radial distribution function (RDF). Our study shows that, for fixed Ti core size, the melting temperature decreases with A1 shell thickness, while the crystallizing temperature and glass formation temperature increase with A1 shell thickness. Diverse melting mechanisms have been discovered for different Ti core sized with fixed A1 shell thickness nanoparticles. The melting temperature increases with the Ti core radius. The trend agrees well with the theoretical phase diagram of bimetallic nanoparticles. In addition, the glass phase formation of A1-Ti nanoparticles for the fast cooling rate of 12 K/ps, and the crystal phase formation for the low cooling rate of 0.15 K/ps. The icosahedron structure is formed in the frozen 4366 A1-Ti atoms for the low cooling rate.
基金This work is supported by Science and Technology Public Project Fund of Henan Province(202102310567).
文摘The purpose of the study is to implement a new model based on the Navier-Stokes equations for the characterization of landslide sediments interacting with a moving fluid.The model is implemented by combining Hypermesh,the LS-DYNA software and MATLAB.The results show that the main factors affecting the permeability of landslide sediments are the genetic mechanism,the structure and composition of materials,material lithology,and stress.The characteristics and mechanism of permeability changes are determined by adjusting the water levels of fluids.It is found that the permeability of landslide sediments increases at the front and decreases in the middle and at the rear of the considered domain.The magnitude of the internal flow for the whole system decreases first and then increases with a change in the water level during seepage.
文摘This paper reports the detailed preparation and phosphorescence properties of Eu2+-activated Ca2ZnSi2O7 phosphors by a modified solid-state reaction.Phase-pure crystalline Ca2ZnSi2O7 is obtained at 600℃,a much lower temperature than by conventional solid-state reaction and the preparation process of Ca2ZnSi2O7 is simple.The obtained phosphors showed three emission peaks at 480,580 and 620 nm,respectively.Auxiliary activator R3+(R=Dy,Nd,Tm) would enhance their luminescent properties.
文摘Chinese martial arts have a long history, profound, which is an integral part of Chinese traditional culture of grandeur. China joined the WTO and the Beijing Olympic Games "has a rich cultural heritage of thousands of years of Chinese martial arts with its unique charm and much of the world' s attention." In the face of opportunities and challenges, the international spread of martial arts has become an irresistible trend. "First of propagation, the spread of the concept of martial arts and martial arts were defined international spread, and it were explains martial international spread of cultural level societal level and significance of the economic level, dialectical judge the outcome of the international transmission acquired with the problems." Secondly, the traditional martial arts culture for martial international dissemination presented aphasia phenomenon, by means of the analysis of the advanced nature of martial arts culture, the martial arts and cultural heritage considered as the center of gravity advantages, not only to absorb the multicultural essence of martial arts culture useful, but also highlight the ethnic characteristics of martial arts culture, martial arts culture to enhance capacity external radiation, the Chinese martial arts as a complete all- round cultural forms, multi-level, multi-an^le display, promote the Chinese martial arts to the world in a more in-depth. "
文摘In the US and British literature, there are many works using China or the Chinese people as depict objects. With the development of American and British literature, the shape of the image of China is diverse. Currently, the research of the image of China or Chinese people in the US and British literature has yielded fruitful results, the majority concentrated on the study before the new century writers and representative works. In the new century, the causes and significance of the image of China and the Chinese people in American literature have the positive impact on self-awareness and self-construction of the China' s image.
文摘Multidimensional Scale Evaluation Rules as a performer in the field of learning assessment is feasible, but for each dimension settings, level settings and value setting need to be developed according to the actual raters, object evaluation, the focus of the evaluation. Scores of overall dimensions use variance analysis, and the results show a significant difference. In sub-dimension score comparison, the high group and low group both got higher scores in the degree of difficulty performing works and read music accuracy. The high group and low group are different on dimensions of the lowest score. Total scores in the scale of multi-dimensional evaluation of rules are positively correlated on the scores on the improvising horizontal dimension, but the correlation is not very high level, that is not all students who is better in playing levels, and they can get higher scores on the improvising horizontal dimension. Using multi-dimensional scale scores and teacher direct evaluation rules score are significantly different for student achievement.
文摘The distance effect of the doped heteroatoms away from the catalytic centers has rarely been reported.In this work,we conducted density functional theory calculations to thoroughly investigate the influence of heteroatom(N,P,B,and S atoms)doping distance on the oxygen reduction reaction(ORR)activity of graphene-based FeN_(4)sites.We uncovered a Sabatier-like relationship between heteroatom doping distance and ORR activity of FeN_(4)sites.The nearest doping does not significantly improve and even block the ORR activity of FeN_(4)sites.Optimal ORR activity is achieved when the heteroatoms are 4-5Å(N,P,and S atoms)or 6-7Å(B atoms)away from the Fe atoms.Analysis of electronic structure indicates that distance effect can modulate the local chemical environment of Fe atoms,thereby account for the changes in ORR activity along with the doping distance and doping atoms.This study provides insights into the influence of heteroatom doping on the chemical environment of reaction active centers,and provides the theoretical guidance for controlling the doping distance of heteroatoms to achieve optimal catalytic activity and selectivity.
基金supported from the China Postdoctoral Science Foundation (2020M682250)the Natural Science Foundation of Shandong Province (ZR2022QB062,ZR2021MB070)the DNL Cooperation Fund,CAS (DNL202010)。
文摘Developing stable electrodes for seawater splitting remains a great challenge due to the detachment of catalysts at a large operating current and severe anode corrosion caused by chlorine.Herein,divalent anion intercalation and etching-hydrolysis strategies are deployed to synthesize the ultra-stable anode,dendritic Fe(OH)_(3) grown on Ni(SO_4)_(0.3)(OH)_(1.4)–Ni(OH)_(2).Experimental results reveal that the anode exhibits good activity and excellent stability in alkaline simulated seawater.After 500 h,the current density operated at 1.72 V remains 99.5%,about 210 m A cm^(-2).The outstanding stability originates from the etchinghydrolysis strategy,which strengthens the interaction between the catalyst and the carrier and retards thus the detachment of catalysts at a large current density.Besides,theoretical simulations confirm that the intercalated divalent anions,such as SO_4^(2-) and CO_(3)^(2-),can weaken the adsorption strength of chlorine on the surface of catalysts and hinder the coupling and hybridization between chlorine and nickel,which slows down the anode corrosion and improves catalytic stability.Furthermore,the twoelectrode system shows the remarkable 95.1% energy efficiency at 2,000 A m-2and outstanding stability in 6 mol L^(-1) KOH +seawater at 80 ℃.
基金supported by the Start-up Foundation of Nanjing Tech Universitythe National Natural Science Foundation of China (61904080, 61801210, 91833302)+3 种基金the Natural Science Foundation of Jiangsu Province (BK20190670, BK20180686)the Natural Science Foundation of Colleges and Universities in Jiangsu Province (19KJB530008)the Innovation Scientists and Technicians Team Construction Projects of Henan Province (CXTD2017002)the funding for “Distinguished professors” and “High-level talents in six industries” of Jiangsu Province and Technology Innovation Project for Overseas Scholar in Nanjing。
文摘The lithium-sulfur battery has attracted enormous attention as being one of the most significant energy storage technologies due to its high energy density and cost-effectiveness.However,the "shuttle effect" of polysulfide intermediates represents a formidable challenge towards its wide applications.Herein,we have designed and synthesized two-dimensional Cu,Zn and Sn-based multimetallic sulfide nanosheets to construct multi-active sites for the immobilization and entrapment of polysulfides with offering better performance in liquid Li2S6-based lithium-polysulfide batteries.Both experimental measurements and theoretical computations demonstrate that the interfacial multi-active sites of multimetallic sulfides not only accelerate the multi-chained redox reactions of highly diffusible polysulfides,but also strengthen affinities toward polysulfides.By adopting multimetallic sulfide nanosheets as the sulfur host,the liquid Li2 S6-based cell exhibits an impressive rate capability with 1200 mAh/g and retains 580 mAh/g at 0.5 mA/cm^(2) after 1000 cycles.With high sulfur mass loading conditions,the cell with 2.0 mg/cm^(2) sulfur loading delivers a cell capacity of 1068 mAh/g and maintains 480 mAh/g with 0.8 mA/cm^(2) and 500 cycles.This study provides new insights into the multifunctional material design with multi-active sites for elevated lithium-polysulfide batteries.
基金This research was supported by Key Project in Science and Technology Agency of Henan Province(Nos.132102310261 and 142102310147)Natural Science Project in Department of Education of Henan Province(Nos.13B360981 and 14B360011)+1 种基金Henan Province Department of Education Teachers,the backbone of Youth Fund(2013GGJS-220)and Key Project in Science and Technology Agency of Zhengzhou City(No.120140790).
文摘Objective:α-Glucosidase inhibitors can be used as a new class of antidiabetic drug.By competitively inhibiting glycosidase activity,these inhibitors help to prevent the fast breakdown of sugars and thereby control the blood sugar level.This study provides a wealth of information aboutα-glucosidase inhibitors isolated from medicinal plants;this knowledge will be useful in finding more potent antidiabetic candidates from the natural resources for the clinical development of antidiabetic therapeutics.Results:411 compounds exhibitingα-glucosidase inhibitory activity were summarized and isolated them from medicinal plants.The compound classes isolated include:terpenes(61)from 14 genus,alkaloids(37)from 11 genus,quinines(49)from 4 genus,flavonoids(103)from 24 genus,phenols(37)from 9 genus,phenylpropanoids(73)from 20 genus,sterides(8)from 5 genus,and other types of compounds(43).Conclusion:Compounds withα-glucosidase inhibitory activity are abundant in nature and can be obtained from several sources.They have highα-glucosidase inhibitory potential,and can be clinically developed for treating diabetes mellitus.
基金National Key R&D Program of China(2018YFD040020)Industry&University Research Project in Henan Province(182107000033).
文摘Cordyceps militaris,belongs to Clavicipitaceae family,was investigated for its chemical compounds,and six compounds were isolated and purified by silica gel column chromatography,Sephadex LH-20 and recrystallization,and their structures were elucidated by spectral techniques and physicochemical properties as ergosterol(1),adenosine(2),cordycepin(3),ergosterol peroxide(4),tetracosanoic acid 2,3-dihydroxypropylester(5),mannitol(6).Procoagulant activity was screened by assaying the activated partial thromboplastin time(APTT),prothrombin time(PT),thrombin time(TT)and fibrinogen(FIB)in vitro.The results indicated that ergosterol,adenosine,cordycepin,ergosterol peroxide and mannitol showed strong procoagulant activity.
文摘The mechanical properties of magnesium alloys at both ambient and elevated temperatures can be improved with the existence of Mg2Si phase in the matrix.However,these properties can be deteriorated if the Mg2Si phase is of coarse Chinese script type.Effects of the silicocalcium addition on the microstructure and properties of an Mg-6Al-0.5Mn alloy(AM60)were studied.The microstructure of the alloy with the addition of silicocalcium is featured with dispersedly distributed small polygonal type Mg2Si phases.The microhardness,tensile strength,percentage elongation and toughness of as-cast AM60+1.0Si-Ca alloy are 20%,13.3%,28.5% and 50% higher than these of AM60 alloy respectively.Further corrosion measurements showed that the silicocalcium-modified AM60 alloy increases the corrosion potential by 0.04V and decreases the lost weight corrosion rate by 45%.
基金This study was sponsored by the“Civil Engineering,Brand Major Construction Site of Private Universities of Education Department of Henan Province 2017”(Henan Finance and Education:[2016]119).
文摘This paper investigates the thermal performance of prefabricated exterior walls using the Computational Fluid Dynamics method to reduce energy consumption.The thermal performance of the prefabricated exterior wall was numerically simulated using the software ANSYS Fluent.The composite wall containing the cavity is taken as the research object in this paper after analysis.The simulation suggests that when the cavity thickness is 20 mm and 30 mm,the heat transfer coefficient of the air-sandwich wall is 1.3 and 1.29,respectively.Therefore,the optimal width of the cavity is 20 mm,and the most suitable material is the aerated concrete block.In addition,a comparative analysis is conducted on the cavity temperature in the wall under different conditions.It is proven that an intelligent environment control system can significantly improve thermal efficiency and provide a solid theoretical basis for further research in the external insulation of prefabricated buildings.