This study is focused on the prediction of mining subsidence and its impact on the environment in the Hongqi mining area. The study was carried out by means of a probability integral model based, in first instance bas...This study is focused on the prediction of mining subsidence and its impact on the environment in the Hongqi mining area. The study was carried out by means of a probability integral model based, in first instance based on field surveys and the analysis of data collected from this area. Isolines of mining sub- sidence were then drawn and the impact caused by mining subsidence on the environment was analyzed quantitatively by spatial analysis with Geographic Information System （GIS）. The results indicate that the subsidence area of the first working-mine can be as large as 2.54 km2, the maximum subsidence is 3440 mrn which will cause 1524 houses to be relocated. The entire subsidence area of the mine can reach 8.09 km2, with a maximum subsidence of 3590 ram. Under these circumstances the value of the loss of ecosystem services Will reach 5.371 million Yuan and the cost of relocating buildings will increase to 6.858 million Yuan.展开更多
In pedestrian re-recognition,the traditional pedestrian re-recognition method will be affected by the changes of background,veil,clothing and so on,which will make the recognition effect decline.In order to reduce the...In pedestrian re-recognition,the traditional pedestrian re-recognition method will be affected by the changes of background,veil,clothing and so on,which will make the recognition effect decline.In order to reduce the impact of background,veil,clothing and other changes on the recognition effect,this paper proposes a pedestrian re-recognition method based on the cycle-consistent generative adversarial network and multifeature fusion.By comparing the measured distance between two pedestrians,pedestrian re-recognition is accomplished.Firstly,this paper uses Cycle GAN to transform and expand the data set,so as to reduce the influence of pedestrian posture changes as much as possible.The method consists of two branches:global feature extraction and local feature extraction.Then the global feature and local feature are fused.The fused features are used for comparison measurement learning,and the similarity scores are calculated to sort the samples.A large number of experimental results on large data sets CUHK03 and VIPER show that this new method reduces the influence of background,veil,clothing and other changes on the recognition effect.展开更多
Pleurotus spp.was one of the most precious and common edible fungi,polysaccharides were the main active component.The structural,biological activities and structure-activity relationship(SAR)of polysaccharides from Pl...Pleurotus spp.was one of the most precious and common edible fungi,polysaccharides were the main active component.The structural,biological activities and structure-activity relationship(SAR)of polysaccharides from Pleurotus spp.were systematically reviewed.On the basis of structure and biological activity,structure-activity relationships were also analyzed and discussed to look forward to its future research direction and application prospect.In the past 5 years,about 30 kinds of polysaccharides were isolated from Pleurotus spp.,and their preliminary structures were studied,but the fine structures seldomly reported.The polysaccharides showed the activities of immunomodulatory,hypoglycemic,anti-inflammatory,antioxidant,anti-ageing,hepatoprotective,anti-tumor,hypolipidemic and regulating intestinal flora,but the mechanism was needed further study.There were few studies on the SAR of polysaccharides from Pleurotus,and the polysaccharides of P.eryngii were studied.It was found that the biological activities of polysaccharides were affected by molecular weight,monosaccharide composition,sugar chain structure and configuration.In addition,sulfonation and selenization could significantly increase the bioactivities of polysaccharides.These findings might help to better understand the research status of polysaccharides from Pleurotus spp.and provided a scientific basis for their application as functional foods.展开更多
We report a fast in situ seeding approach based on zinc（II） porphyrin （ZnP） under white light irradiation, leading to uniform spherical platinum nanodendrites with tunable sizes. The platinum nanodendrites exhibit...We report a fast in situ seeding approach based on zinc（II） porphyrin （ZnP） under white light irradiation, leading to uniform spherical platinum nanodendrites with tunable sizes. The platinum nanodendrites exhibit significantly improved electrocatalytic activities toward oxygen reduction reaction （ORR） and methanol oxidation reaction （MOR） compared with commercial platinum black.展开更多
With rapid developments in the field of very large-scale integrated circuits,heat dissipation has emerged as a significant factor that restricts the high-density integration of chips.Due to their high thermal conducti...With rapid developments in the field of very large-scale integrated circuits,heat dissipation has emerged as a significant factor that restricts the high-density integration of chips.Due to their high thermal conductivity and low thermal expansion coefficient,diamond/Cu composites have attracted considerable attention as a promising thermal management material.In this study,a surface tungsten carbide gradient layer coating of diamond particles has been realized using comprehensive magnetron sputtering technology and a heat treatment process.Diamond/Cu composites were prepared using high-temperature and high-pressure technology.The results show that,by adjusting the heat treatment process,tungsten carbide and di-tungsten carbide are generated by an in situ reaction at the tungsten–diamond interface,and W–WC–W_(2)C gradient layer-coated diamond particles were obtained.The diamond/Cu composites were sintered by high-temperature and high-pressure technology,and the density of surface-modified diamond/Cu composites was less than 4 g cm^(-3).The W–WC–W_(2)C@diamond/Cu composites have a thermal diffusivity as high as 331 mm^(2)s^(-1),and their thermal expansion coefficient is as low as 1.76×10^(-6)K^(-1).The interface coherent structure of the gradient layer-coated diamond/copper composite can effectively improve the interface heat transport efficiency.展开更多
In an attempt to elucidate the biological effects and underlying mutations involving flower color in ornamental plants following carbon ion beam radiation,shoots of geranium were exposed at dosages of 0,10,15,30,and40...In an attempt to elucidate the biological effects and underlying mutations involving flower color in ornamental plants following carbon ion beam radiation,shoots of geranium were exposed at dosages of 0,10,15,30,and40 Gy,and one flower color mutant was obtained.The morphological characteristics,physiological aspects,and DNA polymorphisms between wild-type and flower color mutants were analyzed.The colors of petal,peduncle,pistil,and stamen of the mutant displayed significant differences compared to those of the wild-type.Compared to the original plants,the total anthocyanin content in the petals of the mutant significantly decreased,resulting in a light pink petal phenotype.DNA polymorphisms detected by random amplified polymorphic DNA analysis showed that the ratio of different bands between the wild-type and mutant reached up to 13.2%.The present study demonstrates that carbon ion beam irradiation is effective in inducing genomic variations,resulting in flower color geranium mutants within a relatively short period of time.Meanwhile,the developed flower-color mutants may be potentially used in future mutational research studies involving ornamental plants.展开更多
Aims our study quantified the combined effects of fertilization and inoculation with arbuscular mycorrhizal fungi(AMF)on grain yield and allocation of biomass and nutrients in field-grown rice(Oryza sativa l.).Methods...Aims our study quantified the combined effects of fertilization and inoculation with arbuscular mycorrhizal fungi(AMF)on grain yield and allocation of biomass and nutrients in field-grown rice(Oryza sativa l.).Methods a two-factor experiment was conducted at a field site in northeast of China(in shuangcheng,Heilongjiang Province,songhua river basin):six nitrogen-phosphorus-potassium fertilizer levels were provided(0,20,40,60,80 and 100%of the local norm of ferti-lizer supply),with or without inoculation with Glomus mosseae.at maturity,we quantified the percentage of root length colonization by AMF,grain yield,shoot:root ratios,shoot N and P contents and nutrients allocated to panicles,leaves and stems.Important Findingsas expected,inoculation resulted in greatly increased AMF colo-nization,which in turn led to higher shoot:root ratios and greater shoot N contents.shoot:root ratios of inoculated rice increased with increasing fertilization while there was a significant interaction between fertilization and inoculation on shoot:root ratio.additionally,a F inoculation increased panicle:shoot ratios,panicle N:shoot N ratios and panicle P:shoot P ratios,especially in plants grown at low fertilizer levels.Importantly,inoculated rice exhibited higher grain yield,with the maximum improvement(near 62%)at the lower fertilizer end.our results showed that(i)AMFinoculated plants conform to the functional equilibrium theory,albeit to a reduced extent compared to non-inoculated plants and(ii)AMF inoculation resulted in greater allocation of shoot biomass to panicles and increased grain yield by stimulating N and P redis-tribution to panicles.展开更多
Non-equilibrium solidification structures of Cu55Ni45 and Cu55Ni43Co2 alloys were prepared by the molten glass purification cycle superheating method.The variation of the recalescence phenomenon with the degree of und...Non-equilibrium solidification structures of Cu55Ni45 and Cu55Ni43Co2 alloys were prepared by the molten glass purification cycle superheating method.The variation of the recalescence phenomenon with the degree of undercooling in the rapid solidification process was investigated using an infrared thermometer.The addition of the Co element affected the evolution of the recalescence phenomenon in Cu-Ni alloys.The images of the solid-liquid interface migration during the rapid solidification of supercooled melts were captured by using a high-speed camera.The solidification rate of Cu-Ni alloys,with the addition of Co elements,was explored.Finally,the grain refinement structure with low supercooling was characterised using electron backscatter diffraction(EBSD).The effect of Co on the microstructural evolution during nonequilibrium solidification of Cu-Ni alloys under conditions of small supercooling is investigated by comparing the microstructures of Cu55Ni45 and Cu55Ni43Co2 alloys.The experimental results show that the addition of a small amount of Co weakens the recalescence behaviour of the Cu55Ni45 alloy and significantly reduces the thermal strain in the rapid solidification phase.In the rapid solidification phase,the thermal strain is greatly reduced,and there is a significant increase in the characteristic undercooling degree.Furthermore,the addition of Co and the reduction of Cu not only result in a lower solidification rate of the alloy,but also contribute to the homogenisation of the grain size.展开更多
Low-temperature sintered(Na_(1/2)Bi_(1/2))_(0.935)Ba_(0.065)Ti_(0.975)(Fe_(1/2)Nb_(1/2))_(0.025)O_(3)(NBT-BT-0.025FN)lead-free incipient piezoceramics were investigated using high-purity Li_(2)CO_(3) as sintering aids...Low-temperature sintered(Na_(1/2)Bi_(1/2))_(0.935)Ba_(0.065)Ti_(0.975)(Fe_(1/2)Nb_(1/2))_(0.025)O_(3)(NBT-BT-0.025FN)lead-free incipient piezoceramics were investigated using high-purity Li_(2)CO_(3) as sintering aids.With the ≤0.5 wt%Li_(2)CO_(3) addition,the introduced Li^(+) cations precede to enter the A-sites of the perovskite lattice to compensate for the A-site deficiencies.Once the addition exceeds 0.5 wt%,the excess Lit cations will occupy B-sites and give rise to the generation of oxygen vacancies,which accelerate the mass transport and thus lower the sintering temperature effectively from 1100℃ down to 925℃.It was also found that a small amount of Lit addition has little effect on the phase structure and electromechanical properties of the system,but overweight seriously disturbs these characteristics because of the large lattice distortion.The sintered NBT-BT-0.025FN incipient piezoceramics with 1.25 wt%Li_(2)CO_(3) addition at 925℃ provides a large strain of 0.33% and a corresponding large signal piezoelectric coefficient d_(33)^(*) of 550 pm/V at 60 kV/cm,indicating this system is a very promising candidate for lead-free co-fired multilayer actuator application.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
Hydrogen peroxide(H_(2)O_(2))is an efficient oxidant with multiple uses ranging from chemical synthesis to wastewater treatment.The in-situ H_(2)O_(2)production via a two-electron oxygen reduction reaction(ORR)will br...Hydrogen peroxide(H_(2)O_(2))is an efficient oxidant with multiple uses ranging from chemical synthesis to wastewater treatment.The in-situ H_(2)O_(2)production via a two-electron oxygen reduction reaction(ORR)will bring H_(2)O_(2)beyond its current applications.The development of carbon materials offers the hope for obtaining inexpensive and high-performance alternatives to substitute noble-metal catalysts in order to provide a full and comprehensive picture of the current state of the art treatments and inspire new research in this area.Herein,the most up-to-date findings in theoretical predictions,synthetic methodologies,and experimental investigations of carbon-based catalysts are systematically summarized.Various electrode fabrication and modification methods were also introduced and compared,along with our original research on the air-breathing cathode and three-phase interface theory inside a porous electrode.In addition,our current understanding of the challenges,future directions,and suggestions on the carbon-based catalyst designs and electrode fabrication are highlighted.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
Moistube irrigation was driven by the gradient of water potential inside and outside the pipe wall,which has the advantages of continuous irrigation during the crop growth period.However,the response mechanism of soil...Moistube irrigation was driven by the gradient of water potential inside and outside the pipe wall,which has the advantages of continuous irrigation during the crop growth period.However,the response mechanism of soil nutrients and enzyme activities of greenhouse tomatoes under the integration of water and fertilizer by moistube irrigation is still unclear.In order to explore the changes in soil nutrients and enzyme activities of greenhouse tomatoes regulated by irrigation and fertilization in moistube irrigation greenhouse,a completely randomized experimental design was conducted to explore the effects of different irrigation amounts(I,controlling the work-ing pressure head of moistube to achieve different irrigation amount gradients,capillary working pressure was 1(I1),2(I2),3(I3)m)and fertilization amounts(F,single fertilization amount was 100(F1),200(F2),300(F3)kg/hm2)on soil nutrients,enzyme activities and yield of greenhouse tomato.It was found that with the increase of I,the total organic carbon content(TOC),soilβ-glucosidase(BG),leucine amino peptidase(LAP),N-acetylglucosaminidase(NAG),and alkaline phosphatase(AP)activities enzyme of greenhouse tomato soil increasedfirst and then decreased.When the I increased from I1 to I3,the soil total nitrogen(TN)decreased by 5.07%and 4.91%,respectively,and the soil total phosphorus(TP)by 4.37%and 4.22%,respectively.With the increase of fertilizer amounts,the TOC of tomato soil increasedfirst and then decreased,the activities of BG,LAP,NAG and AP in soil increasedfirst and then decreased,and the contents of TN and TP in soil decreased by 4.79%and 4.68%,12.32%and 10.47%,respectively.The yield of tomatoes treated with I2 was significantly higher than that of I1 and I3 by about 13.99%and 1.29%,respectively.The tomato yield of F2 treatment was significantly higher than that of F1 and F3 treatments by about 22.57%and 1.72%,respectively.Based on the analysis of stoichiometry,it was found that soil carbon was more scarcity than nitrogen in greenhouse tomatoes under the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
This paper focuses on the problems encountered in the production process of electronic-grade polycrystalline silicon.It points out that the characterization of electronic-grade polycrystalline silicon is mainly concen...This paper focuses on the problems encountered in the production process of electronic-grade polycrystalline silicon.It points out that the characterization of electronic-grade polycrystalline silicon is mainly concentrated at the macroscopic scale,with relatively less research at the mesoscopic and microscopic scales.Therefore,we utilize the method of physical polishing to obtain polysilicon characterization samples and then the paper utilizes metallographic microscopy,scanning electron microscopy-electron backscatter diffraction technology,and aberration-corrected transmission electron microscopy technology to observe and characterize the interface region between silicon core and matrix in the deposition process of electronic-grade polycrystalline silicon,providing a full-scale characterization of the interface morphology,grain structure,and orientation distribution from macro to micro.Finally,the paper illustrates the current uncertainties regarding polycrystalline silicon.展开更多
Large-size electronic-grade polycrystalline silicon is an important material in the semiconductor industry with broad application prospects.However,electronic-grade polycrystalline silicon has extremely high requireme...Large-size electronic-grade polycrystalline silicon is an important material in the semiconductor industry with broad application prospects.However,electronic-grade polycrystalline silicon has extremely high requirements for production technology and currently faces challenges such as carbon impurity breakdown,microstructure and composition nonuniformity and a lack of methods for preparing large-size mirror-like polycrystalline silicon samples.This paper innovatively uses physical methods such as wire cutting,mechanical grinding and ion thinning polishing to prepare large-size polycrystalline silicon samples that are clean,smooth,free from wear and have clear crystal defects.The material was characterized at both macroscopic and microscopic levels using metallographic microscopy,scanning electron microscopy(SEM)with backscattered electron diffraction(EBSD)techniques and scanning transmission electron microscopy(STEM).The crystal structure changes from single crystal silicon core to the surface of the bulk in the large-size polycrystalline silicon samples were revealed,providing a technical basis for optimizing and improving production processes.展开更多
The micro-sprinkler irrigation mulched(MSM)has been suggested as a novel water-saving approach in con-trolled environment agriculture.However,the effects of microbial community structure and enzyme activity in the rhi...The micro-sprinkler irrigation mulched(MSM)has been suggested as a novel water-saving approach in con-trolled environment agriculture.However,the effects of microbial community structure and enzyme activity in the rhizosphere soil on crop growth under MSM remain unclear.This study conducted a randomized experimen-tal design using greenhouse tomatoes to investigate changes in bacterial community structure and enzyme activity in rhizosphere soil under different irrigation frequencies(F)and amounts(I)of MSM.Thefindings revealed that with the increase of F or I,The total count of soil bacteria in tomatoesfirst rose and then fell in terms of Opera-tional Taxonomic Units(OTUs)classification.Compared to other F,the most abundance of nitrogen and phos-phorus metabolism genes and enzyme activities were observed with a 5-day F.Moreover,the diversity of soil bacterial community structure initially rose before eventually declining with the increase of the I.Applying 1.00 Epan(cumulative evaporation of a 20 cm standard pan)under MSM helped boost the abundance of nitrogen and phosphorus metabolism functional genes in soil bacteria,ensuring higher enzyme activities related to nitro-gen,carbon,and phosphorus metabolism in the rhizosphere soil of tomatoes.Tomatoes’yield initially rose before eventually declining with the increase in F or I,whereas I had a more significant effect on yield.A 1.00%increase in I yielded a minimum of 39.24%increase in tomato yield.The study showed a positive correlation between soil bacterial community,soil enzyme activity,and greenhouse tomato yield under MSM.Considering the results comprehensively,the combined irrigation mode of F of 5 d and I of 1.00 Epan was recommended for greenhouse tomatoes under MSM.This conclusion provides theoretical support for water-saving practices and yield improve-ment in facility agriculture,especially tomato cultivation.展开更多
Oxalic acid(C_(2))is a significant tracer of secondary organic aerosols(SOA),yet its precursors,evolutionary processes,and formation mechanisms are not fully understood.This knowledge gap leads to uncertainties in eva...Oxalic acid(C_(2))is a significant tracer of secondary organic aerosols(SOA),yet its precursors,evolutionary processes,and formation mechanisms are not fully understood.This knowledge gap leads to uncertainties in evaluating the climate effect and global budget of SOA.Here we compared the size distribution,mixing fraction,and evolutionary mechanism of C_(2)-containing particles between summer and winter.In summer,the number of C_(2) particles and their homologs decreased compared to winter.However,the proportion of C_(2) relative to the total number of determined particles increased,indicating that the summertime particles are more aged.Higher relative aerosol acidity(Rra)and lower in-situ pH(pHis)in summer suggest that particles are more acidic during this season.Correlation analysis and temporal variation characteristics suggest that from 9:00 to 15:00 in summer,C_(2) particles mostly originate from the photochemical decomposition of larger dicarboxylic aids,driven by O3 concentration.Conversely,from 16:00 to 20:00,C_(2) particles are predominantly formed through aqueous-phase oxidation,influenced by higher relative humidity(RH),aerosol liquid water content(ALWC),and acidity.Additionally,heavy metal particles were the predominant type of C_(2) particles,and C_(2) particles exhibited an opposite diurnal variation to Fe in summer,suggesting that the photolysis of iron oxalate complexes is an important sink of C_(2) particles during this period.In winter,biomass burning(BB)particles were the most abundant,and a robust correlation between levoglucosan and C_(2) particles indicated a substantial influence of BB on C_(2) particles.The aqueous generation of C_(2) particles fromα-dicarbonyls driven by acidity was most effective when RH varied from 40%to 60%in the wintertime state of particles.These findings highlight the hourly and seasonal variations in the sources and evolutionary processes of SOA.Such variations must be considered in developing control measures and simulating the climate effect of SOA.展开更多
This paper aims at understanding the price dynamics generated by the interaction of traders relying on heterogeneous expectations in an asset pricing model.In the present work the authors analyze a financial market po...This paper aims at understanding the price dynamics generated by the interaction of traders relying on heterogeneous expectations in an asset pricing model.In the present work the authors analyze a financial market populated by five types of boundedly rational speculators-two types of fundamentalists,two types of chartists and trend followers which submit buying/selling orders according to different trading rules.The authors formulate a stock market model represented as a 2 dimensional piecewise linear discontinuous map.The proposed contribution to the existing financial literature is two aspects.First,the authors perform study of the model involving a 2 dimensional piecewise linear discontinuous map through a combination of qualitative and quantitative methods.The authors focus on the existence conditions of chaos and the multi-stability regions in parameter plane.Related border collision bifurcation curves and basins of multi-attractors are also given.The authors find that chaos or quasi-period exists only in the case of fixed point being a saddle(regular or flip)and that the coexistence of multiple attractors may exist when the fixed point is an attractor,but it is common for spiral and flip fixed points.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
基金Support for this work, provided by the Science and Technology Project of the Land and Resources Department of Henan Province (No.0979)
文摘This study is focused on the prediction of mining subsidence and its impact on the environment in the Hongqi mining area. The study was carried out by means of a probability integral model based, in first instance based on field surveys and the analysis of data collected from this area. Isolines of mining sub- sidence were then drawn and the impact caused by mining subsidence on the environment was analyzed quantitatively by spatial analysis with Geographic Information System （GIS）. The results indicate that the subsidence area of the first working-mine can be as large as 2.54 km2, the maximum subsidence is 3440 mrn which will cause 1524 houses to be relocated. The entire subsidence area of the mine can reach 8.09 km2, with a maximum subsidence of 3590 ram. Under these circumstances the value of the loss of ecosystem services Will reach 5.371 million Yuan and the cost of relocating buildings will increase to 6.858 million Yuan.
文摘In pedestrian re-recognition,the traditional pedestrian re-recognition method will be affected by the changes of background,veil,clothing and so on,which will make the recognition effect decline.In order to reduce the impact of background,veil,clothing and other changes on the recognition effect,this paper proposes a pedestrian re-recognition method based on the cycle-consistent generative adversarial network and multifeature fusion.By comparing the measured distance between two pedestrians,pedestrian re-recognition is accomplished.Firstly,this paper uses Cycle GAN to transform and expand the data set,so as to reduce the influence of pedestrian posture changes as much as possible.The method consists of two branches:global feature extraction and local feature extraction.Then the global feature and local feature are fused.The fused features are used for comparison measurement learning,and the similarity scores are calculated to sort the samples.A large number of experimental results on large data sets CUHK03 and VIPER show that this new method reduces the influence of background,veil,clothing and other changes on the recognition effect.
基金supported by National Key R&D Program of China(2018YFD0400200)Major Public Welfare Projects in Henan Province(201300110200)+1 种基金Research on Precision Nutrition and Health Food,Department of Science and Technology of Henan Province(CXJD2021006)The Key Project in Science and Technology Agency of Henan Province(202102110283 and 212102110019).
文摘Pleurotus spp.was one of the most precious and common edible fungi,polysaccharides were the main active component.The structural,biological activities and structure-activity relationship(SAR)of polysaccharides from Pleurotus spp.were systematically reviewed.On the basis of structure and biological activity,structure-activity relationships were also analyzed and discussed to look forward to its future research direction and application prospect.In the past 5 years,about 30 kinds of polysaccharides were isolated from Pleurotus spp.,and their preliminary structures were studied,but the fine structures seldomly reported.The polysaccharides showed the activities of immunomodulatory,hypoglycemic,anti-inflammatory,antioxidant,anti-ageing,hepatoprotective,anti-tumor,hypolipidemic and regulating intestinal flora,but the mechanism was needed further study.There were few studies on the SAR of polysaccharides from Pleurotus,and the polysaccharides of P.eryngii were studied.It was found that the biological activities of polysaccharides were affected by molecular weight,monosaccharide composition,sugar chain structure and configuration.In addition,sulfonation and selenization could significantly increase the bioactivities of polysaccharides.These findings might help to better understand the research status of polysaccharides from Pleurotus spp.and provided a scientific basis for their application as functional foods.
基金Acknowledgements This work was partially supported by the National Basic Research Program （973 Program） of China （No. 2012CB215500）, the National High-tech R＆D Program（863 Program） of China （No. 2011AA11A273）, and the National Natural Science Foundation of China （NSFC, Nos. 21003114 and 21103163）. The authors thank Professor John A. Shelnutt at Georgia University, USA for fruitful discussions.
文摘We report a fast in situ seeding approach based on zinc（II） porphyrin （ZnP） under white light irradiation, leading to uniform spherical platinum nanodendrites with tunable sizes. The platinum nanodendrites exhibit significantly improved electrocatalytic activities toward oxygen reduction reaction （ORR） and methanol oxidation reaction （MOR） compared with commercial platinum black.
基金National Natural Science Foundation of China(Grant No.52072327)the China National Key R&D Program(2021YFB3701802)+6 种基金Scientific and Technological Projects of Henan Province(No.232102231050)the Higher Education and Teaching Reformation Project(2014SJGLX064)the Project for Work-station of Zhongyuan scholars of Henan Province(Nos.214400510002,224400510023)the Science and Technology Major Project of Henan Province(No.221100230300)the Postgraduate Education Reform and QualityAcademic Degrees&Graduate Education Reform Project of Henan Province(No.2021SJGLX060Y)the Postgraduate Education Reform and Quality Improvement Project of Henan Province(No.YJS2022JD34)the Science and Technology on Plasma Physics Laboratory(Grant No.JCKYS2021212010).
文摘With rapid developments in the field of very large-scale integrated circuits,heat dissipation has emerged as a significant factor that restricts the high-density integration of chips.Due to their high thermal conductivity and low thermal expansion coefficient,diamond/Cu composites have attracted considerable attention as a promising thermal management material.In this study,a surface tungsten carbide gradient layer coating of diamond particles has been realized using comprehensive magnetron sputtering technology and a heat treatment process.Diamond/Cu composites were prepared using high-temperature and high-pressure technology.The results show that,by adjusting the heat treatment process,tungsten carbide and di-tungsten carbide are generated by an in situ reaction at the tungsten–diamond interface,and W–WC–W_(2)C gradient layer-coated diamond particles were obtained.The diamond/Cu composites were sintered by high-temperature and high-pressure technology,and the density of surface-modified diamond/Cu composites was less than 4 g cm^(-3).The W–WC–W_(2)C@diamond/Cu composites have a thermal diffusivity as high as 331 mm^(2)s^(-1),and their thermal expansion coefficient is as low as 1.76×10^(-6)K^(-1).The interface coherent structure of the gradient layer-coated diamond/copper composite can effectively improve the interface heat transport efficiency.
基金supported by the National Natural Science Foundation of China(Grant Nos.11205218,11275171,and 11405234)the Knowledge Innovation Project of the Chinese Academy of Sciences(CAS)(No.KJCX2-EW-N05)+1 种基金CAS‘‘Light of West China’’Program(No.29Y506020)the Youth Innovation Promotion Association of CAS(No.29Y506030)supported this study
文摘In an attempt to elucidate the biological effects and underlying mutations involving flower color in ornamental plants following carbon ion beam radiation,shoots of geranium were exposed at dosages of 0,10,15,30,and40 Gy,and one flower color mutant was obtained.The morphological characteristics,physiological aspects,and DNA polymorphisms between wild-type and flower color mutants were analyzed.The colors of petal,peduncle,pistil,and stamen of the mutant displayed significant differences compared to those of the wild-type.Compared to the original plants,the total anthocyanin content in the petals of the mutant significantly decreased,resulting in a light pink petal phenotype.DNA polymorphisms detected by random amplified polymorphic DNA analysis showed that the ratio of different bands between the wild-type and mutant reached up to 13.2%.The present study demonstrates that carbon ion beam irradiation is effective in inducing genomic variations,resulting in flower color geranium mutants within a relatively short period of time.Meanwhile,the developed flower-color mutants may be potentially used in future mutational research studies involving ornamental plants.
基金National Natural Science Foundation of China(51179041)Major Science and Technology Program for Water Pollution Control and Treatment(2013ZX07201007)+4 种基金National Creative Research Group from the National Natural Science Foundation of China(51121062)State Key Lab of Urban Water Resource and Environment,Harbin Institute of Technology,China(HIT)(2011TS07)Natural Science Foundation of Hei Longjiang Province,China(E201206)Special Fund for Science and Technology Innovation of Harbin(2012RFLXS026)Australian Research Council Centre of Excellence in Plant Energy Biology(CE140100008 to O.K.A.).
文摘Aims our study quantified the combined effects of fertilization and inoculation with arbuscular mycorrhizal fungi(AMF)on grain yield and allocation of biomass and nutrients in field-grown rice(Oryza sativa l.).Methods a two-factor experiment was conducted at a field site in northeast of China(in shuangcheng,Heilongjiang Province,songhua river basin):six nitrogen-phosphorus-potassium fertilizer levels were provided(0,20,40,60,80 and 100%of the local norm of ferti-lizer supply),with or without inoculation with Glomus mosseae.at maturity,we quantified the percentage of root length colonization by AMF,grain yield,shoot:root ratios,shoot N and P contents and nutrients allocated to panicles,leaves and stems.Important Findingsas expected,inoculation resulted in greatly increased AMF colo-nization,which in turn led to higher shoot:root ratios and greater shoot N contents.shoot:root ratios of inoculated rice increased with increasing fertilization while there was a significant interaction between fertilization and inoculation on shoot:root ratio.additionally,a F inoculation increased panicle:shoot ratios,panicle N:shoot N ratios and panicle P:shoot P ratios,especially in plants grown at low fertilizer levels.Importantly,inoculated rice exhibited higher grain yield,with the maximum improvement(near 62%)at the lower fertilizer end.our results showed that(i)AMFinoculated plants conform to the functional equilibrium theory,albeit to a reduced extent compared to non-inoculated plants and(ii)AMF inoculation resulted in greater allocation of shoot biomass to panicles and increased grain yield by stimulating N and P redis-tribution to panicles.
文摘Non-equilibrium solidification structures of Cu55Ni45 and Cu55Ni43Co2 alloys were prepared by the molten glass purification cycle superheating method.The variation of the recalescence phenomenon with the degree of undercooling in the rapid solidification process was investigated using an infrared thermometer.The addition of the Co element affected the evolution of the recalescence phenomenon in Cu-Ni alloys.The images of the solid-liquid interface migration during the rapid solidification of supercooled melts were captured by using a high-speed camera.The solidification rate of Cu-Ni alloys,with the addition of Co elements,was explored.Finally,the grain refinement structure with low supercooling was characterised using electron backscatter diffraction(EBSD).The effect of Co on the microstructural evolution during nonequilibrium solidification of Cu-Ni alloys under conditions of small supercooling is investigated by comparing the microstructures of Cu55Ni45 and Cu55Ni43Co2 alloys.The experimental results show that the addition of a small amount of Co weakens the recalescence behaviour of the Cu55Ni45 alloy and significantly reduces the thermal strain in the rapid solidification phase.In the rapid solidification phase,the thermal strain is greatly reduced,and there is a significant increase in the characteristic undercooling degree.Furthermore,the addition of Co and the reduction of Cu not only result in a lower solidification rate of the alloy,but also contribute to the homogenisation of the grain size.
基金the generous support by the National Natural Science Foundation of China under grant no.51672092 and U1732117by the Project of Henan Province Science and Technology(Grant No.172102210380)+1 种基金China Postdoctoral Science Foundation funded project no.2018M632847the generous support by Wuhan Morning Light Plan of Youth Science and Technology(No.2017050304010299).
文摘Low-temperature sintered(Na_(1/2)Bi_(1/2))_(0.935)Ba_(0.065)Ti_(0.975)(Fe_(1/2)Nb_(1/2))_(0.025)O_(3)(NBT-BT-0.025FN)lead-free incipient piezoceramics were investigated using high-purity Li_(2)CO_(3) as sintering aids.With the ≤0.5 wt%Li_(2)CO_(3) addition,the introduced Li^(+) cations precede to enter the A-sites of the perovskite lattice to compensate for the A-site deficiencies.Once the addition exceeds 0.5 wt%,the excess Lit cations will occupy B-sites and give rise to the generation of oxygen vacancies,which accelerate the mass transport and thus lower the sintering temperature effectively from 1100℃ down to 925℃.It was also found that a small amount of Lit addition has little effect on the phase structure and electromechanical properties of the system,but overweight seriously disturbs these characteristics because of the large lattice distortion.The sintered NBT-BT-0.025FN incipient piezoceramics with 1.25 wt%Li_(2)CO_(3) addition at 925℃ provides a large strain of 0.33% and a corresponding large signal piezoelectric coefficient d_(33)^(*) of 550 pm/V at 60 kV/cm,indicating this system is a very promising candidate for lead-free co-fired multilayer actuator application.
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 financially supported by the National Natural Science Foundation of China(No.52070140)the Open Project of State Key Laboratory of Urban Water Resource and Environment,Harbin Institute of Technology(No.HC202151)the Postdoctoral Science Foundation of China(2021M702439).
文摘Hydrogen peroxide(H_(2)O_(2))is an efficient oxidant with multiple uses ranging from chemical synthesis to wastewater treatment.The in-situ H_(2)O_(2)production via a two-electron oxygen reduction reaction(ORR)will bring H_(2)O_(2)beyond its current applications.The development of carbon materials offers the hope for obtaining inexpensive and high-performance alternatives to substitute noble-metal catalysts in order to provide a full and comprehensive picture of the current state of the art treatments and inspire new research in this area.Herein,the most up-to-date findings in theoretical predictions,synthetic methodologies,and experimental investigations of carbon-based catalysts are systematically summarized.Various electrode fabrication and modification methods were also introduced and compared,along with our original research on the air-breathing cathode and three-phase interface theory inside a porous electrode.In addition,our current understanding of the challenges,future directions,and suggestions on the carbon-based catalyst designs and electrode fabrication are highlighted.
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The research is funded by the Natural Science Foundation of China(No.41807041)the Science and Technology Research Project of Henan Province(No.242102111101)Social Science Foundation of Shaanxi Province(2023SJ03).
文摘Moistube irrigation was driven by the gradient of water potential inside and outside the pipe wall,which has the advantages of continuous irrigation during the crop growth period.However,the response mechanism of soil nutrients and enzyme activities of greenhouse tomatoes under the integration of water and fertilizer by moistube irrigation is still unclear.In order to explore the changes in soil nutrients and enzyme activities of greenhouse tomatoes regulated by irrigation and fertilization in moistube irrigation greenhouse,a completely randomized experimental design was conducted to explore the effects of different irrigation amounts(I,controlling the work-ing pressure head of moistube to achieve different irrigation amount gradients,capillary working pressure was 1(I1),2(I2),3(I3)m)and fertilization amounts(F,single fertilization amount was 100(F1),200(F2),300(F3)kg/hm2)on soil nutrients,enzyme activities and yield of greenhouse tomato.It was found that with the increase of I,the total organic carbon content(TOC),soilβ-glucosidase(BG),leucine amino peptidase(LAP),N-acetylglucosaminidase(NAG),and alkaline phosphatase(AP)activities enzyme of greenhouse tomato soil increasedfirst and then decreased.When the I increased from I1 to I3,the soil total nitrogen(TN)decreased by 5.07%and 4.91%,respectively,and the soil total phosphorus(TP)by 4.37%and 4.22%,respectively.With the increase of fertilizer amounts,the TOC of tomato soil increasedfirst and then decreased,the activities of BG,LAP,NAG and AP in soil increasedfirst and then decreased,and the contents of TN and TP in soil decreased by 4.79%and 4.68%,12.32%and 10.47%,respectively.The yield of tomatoes treated with I2 was significantly higher than that of I1 and I3 by about 13.99%and 1.29%,respectively.The tomato yield of F2 treatment was significantly higher than that of F1 and F3 treatments by about 22.57%and 1.72%,respectively.Based on the analysis of stoichiometry,it was found that soil carbon was more scarcity than nitrogen in greenhouse tomatoes under the
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.
基金support of the unveiling project of“Application Research on Carbon and Other Trace Impurities and Microstructure Characterization Technology on the Surface of Electronic Grade Polysilicon”by Qinghai Xince Technology Co.,Ltd.of the Huanghe Hydropower Development Co.,Ltd.,project number:XCKJ-FY(2024)No.1(total No.25).
文摘This paper focuses on the problems encountered in the production process of electronic-grade polycrystalline silicon.It points out that the characterization of electronic-grade polycrystalline silicon is mainly concentrated at the macroscopic scale,with relatively less research at the mesoscopic and microscopic scales.Therefore,we utilize the method of physical polishing to obtain polysilicon characterization samples and then the paper utilizes metallographic microscopy,scanning electron microscopy-electron backscatter diffraction technology,and aberration-corrected transmission electron microscopy technology to observe and characterize the interface region between silicon core and matrix in the deposition process of electronic-grade polycrystalline silicon,providing a full-scale characterization of the interface morphology,grain structure,and orientation distribution from macro to micro.Finally,the paper illustrates the current uncertainties regarding polycrystalline silicon.
基金support from the unveiling project by Qinghai Xince Technology Co.,Ltd.,Huanghe Hydropower Development Co.,Ltd.,Project No.XCKJ-FY(2024)No.1(total No.25).
文摘Large-size electronic-grade polycrystalline silicon is an important material in the semiconductor industry with broad application prospects.However,electronic-grade polycrystalline silicon has extremely high requirements for production technology and currently faces challenges such as carbon impurity breakdown,microstructure and composition nonuniformity and a lack of methods for preparing large-size mirror-like polycrystalline silicon samples.This paper innovatively uses physical methods such as wire cutting,mechanical grinding and ion thinning polishing to prepare large-size polycrystalline silicon samples that are clean,smooth,free from wear and have clear crystal defects.The material was characterized at both macroscopic and microscopic levels using metallographic microscopy,scanning electron microscopy(SEM)with backscattered electron diffraction(EBSD)techniques and scanning transmission electron microscopy(STEM).The crystal structure changes from single crystal silicon core to the surface of the bulk in the large-size polycrystalline silicon samples were revealed,providing a technical basis for optimizing and improving production processes.
基金funded by the Natural Science Foundation of China(No.41807041)the Science and Technology Research Project of Henan Province(242102111101)the Mechanical Design,Manufacturing,and Automation Key Discipline of Henan Province(JG[2018]No.119).
文摘The micro-sprinkler irrigation mulched(MSM)has been suggested as a novel water-saving approach in con-trolled environment agriculture.However,the effects of microbial community structure and enzyme activity in the rhizosphere soil on crop growth under MSM remain unclear.This study conducted a randomized experimen-tal design using greenhouse tomatoes to investigate changes in bacterial community structure and enzyme activity in rhizosphere soil under different irrigation frequencies(F)and amounts(I)of MSM.Thefindings revealed that with the increase of F or I,The total count of soil bacteria in tomatoesfirst rose and then fell in terms of Opera-tional Taxonomic Units(OTUs)classification.Compared to other F,the most abundance of nitrogen and phos-phorus metabolism genes and enzyme activities were observed with a 5-day F.Moreover,the diversity of soil bacterial community structure initially rose before eventually declining with the increase of the I.Applying 1.00 Epan(cumulative evaporation of a 20 cm standard pan)under MSM helped boost the abundance of nitrogen and phosphorus metabolism functional genes in soil bacteria,ensuring higher enzyme activities related to nitro-gen,carbon,and phosphorus metabolism in the rhizosphere soil of tomatoes.Tomatoes’yield initially rose before eventually declining with the increase in F or I,whereas I had a more significant effect on yield.A 1.00%increase in I yielded a minimum of 39.24%increase in tomato yield.The study showed a positive correlation between soil bacterial community,soil enzyme activity,and greenhouse tomato yield under MSM.Considering the results comprehensively,the combined irrigation mode of F of 5 d and I of 1.00 Epan was recommended for greenhouse tomatoes under MSM.This conclusion provides theoretical support for water-saving practices and yield improve-ment in facility agriculture,especially tomato cultivation.
基金supported by the National Natural Science Foundation of China (grant No.42177083)the Junior Faculty Support Program for Scientific and Technological Innovations in Shandong Provincial Higher Education Institutions (grant No.2021KJ085).
文摘Oxalic acid(C_(2))is a significant tracer of secondary organic aerosols(SOA),yet its precursors,evolutionary processes,and formation mechanisms are not fully understood.This knowledge gap leads to uncertainties in evaluating the climate effect and global budget of SOA.Here we compared the size distribution,mixing fraction,and evolutionary mechanism of C_(2)-containing particles between summer and winter.In summer,the number of C_(2) particles and their homologs decreased compared to winter.However,the proportion of C_(2) relative to the total number of determined particles increased,indicating that the summertime particles are more aged.Higher relative aerosol acidity(Rra)and lower in-situ pH(pHis)in summer suggest that particles are more acidic during this season.Correlation analysis and temporal variation characteristics suggest that from 9:00 to 15:00 in summer,C_(2) particles mostly originate from the photochemical decomposition of larger dicarboxylic aids,driven by O3 concentration.Conversely,from 16:00 to 20:00,C_(2) particles are predominantly formed through aqueous-phase oxidation,influenced by higher relative humidity(RH),aerosol liquid water content(ALWC),and acidity.Additionally,heavy metal particles were the predominant type of C_(2) particles,and C_(2) particles exhibited an opposite diurnal variation to Fe in summer,suggesting that the photolysis of iron oxalate complexes is an important sink of C_(2) particles during this period.In winter,biomass burning(BB)particles were the most abundant,and a robust correlation between levoglucosan and C_(2) particles indicated a substantial influence of BB on C_(2) particles.The aqueous generation of C_(2) particles fromα-dicarbonyls driven by acidity was most effective when RH varied from 40%to 60%in the wintertime state of particles.These findings highlight the hourly and seasonal variations in the sources and evolutionary processes of SOA.Such variations must be considered in developing control measures and simulating the climate effect of SOA.
基金supported by the Fundamental Research Funds for the Central Universities,South-Central Minzu University under Grant No. CZT20006
文摘This paper aims at understanding the price dynamics generated by the interaction of traders relying on heterogeneous expectations in an asset pricing model.In the present work the authors analyze a financial market populated by five types of boundedly rational speculators-two types of fundamentalists,two types of chartists and trend followers which submit buying/selling orders according to different trading rules.The authors formulate a stock market model represented as a 2 dimensional piecewise linear discontinuous map.The proposed contribution to the existing financial literature is two aspects.First,the authors perform study of the model involving a 2 dimensional piecewise linear discontinuous map through a combination of qualitative and quantitative methods.The authors focus on the existence conditions of chaos and the multi-stability regions in parameter plane.Related border collision bifurcation curves and basins of multi-attractors are also given.The authors find that chaos or quasi-period exists only in the case of fixed point being a saddle(regular or flip)and that the coexistence of multiple attractors may exist when the fixed point is an attractor,but it is common for spiral and flip fixed points.
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.
