Machine learning(ML)integrated with density functional theory(DFT)calculations have recently been used to accelerate the design and discovery of single-atom catalysts(SACs)by establishing deep structure–activity rela...Machine learning(ML)integrated with density functional theory(DFT)calculations have recently been used to accelerate the design and discovery of single-atom catalysts(SACs)by establishing deep structure–activity relationships.The traditional ML models are always difficult to identify the structural differences among the single-atom systems with different modification methods,leading to the limitation of the potential application range.Aiming to the structural properties of several typical two-dimensional MA_(2)Z_(4)-based single-atom systems(bare MA_(2)Z_(4) and metal single-atom doped/supported MA_(2)Z_(4)),an improved crystal graph convolutional neural network(CGCNN)classification model was employed,instead of the traditional machine learning regression model,to address the challenge of incompatibility in the studied systems.The CGCNN model was optimized using crystal graph representation in which the geometric configuration was divided into active layer,surface layer,and bulk layer(ASB-GCNN).Through ML and DFT calculations,five potential single-atom hydrogen evolution reaction(HER)catalysts were screened from chemical space of 600 MA_(2)Z_(4)-based materials,especially V_(1)/HfSn_(2)N_(4)(S)with high stability and activity(Δ_(GH*)is 0.06 eV).Further projected density of states(pDOS)analysis in combination with the wave function analysis of the SAC-H bond revealed that the SAC-dz^(2)orbital coincided with the H-s orbital around the energy level of−2.50 eV,and orbital analysis confirmed the formation ofσbonds.This study provides an efficient multistep screening design framework of metal single-atom catalyst for HER systems with similar two-dimensional supports but different geometric configurations.展开更多
Dispersing metals from nanoparticles into clusters or single atoms often exhibits unique properties such as the inhibition of structure-sensitive side reactions.Here,we reported the use of ion exchange(IE)methods and ...Dispersing metals from nanoparticles into clusters or single atoms often exhibits unique properties such as the inhibition of structure-sensitive side reactions.Here,we reported the use of ion exchange(IE)methods and direct hydrogen reduction to achieve high dispersion of Co species on zincosilicate.The obtained 2Co/Zn-4-IE catalyst achieved an initial propane conversion of 41.4%at a temperature of 550℃in a 25%propane and 75%nitrogen atmosphere for propane dehydrogenation.Visualization of the presence of Co species within specific rings(alpha-α,beta-βand delta-δ)was obtained by aberration-corrected scanning transmission electron microscopy.A series of Fourier transform infrared spectra confirmed the anchoring of Co by specific hydroxyl groups in zincosilicate and the specific coordination environment of Co and its presence in the rings essentially as a single site.The framework Zn for the modulation of the microenvironment and the presence of Co species as Lewis acid active sites(Co-O4)was also supported by density functional theory calculations.展开更多
CO_(2) photoreduction into carbon-based chemicals has been considered as an appropriate way to alleviate the energy issue and greenhouse effect.Herein,the 5,10,15,20-tetra(4-carboxyphenyl)porphyrin cobalt(II)(CoTCPP)h...CO_(2) photoreduction into carbon-based chemicals has been considered as an appropriate way to alleviate the energy issue and greenhouse effect.Herein,the 5,10,15,20-tetra(4-carboxyphenyl)porphyrin cobalt(II)(CoTCPP)has been integrated with BiOBr microspheres and formed the CoTCPP/BiOBr composite.The as-prepared CoTCPP/BiOBr-2 composite shows optimized photocatalytic performance for CO_(2) conversion into CO and CH_(4) upon irradiation with 300 W Xe lamp,which is 2.03 and 2.58 times compared to that of BiOBr,respectively.The introduced CoTCPP significantly enhanced light absorption properties,promoted rapid separation of photogenerated carriers and boosted the chemisorption of CO_(2) molecules.The metal Co^(2+) at the center of the porphyrin molecules also acts as adsorption center for CO_(2) molecules,accelerating the CO_(2) conversion into CO and CH_(4).The possible mechanism of CO_(2) photoreduction was explored by in-situ FT-IR spectra.This work offers a new possibility for the preparation of advanced photocatalysts.展开更多
Alloying and interface effects are effective strategies for enhancing the performance of electrocatalysts in energy-related devices.Herein,dendritic Au-doped platinum-palladium alloy/dumbbell-like bismuth telluride he...Alloying and interface effects are effective strategies for enhancing the performance of electrocatalysts in energy-related devices.Herein,dendritic Au-doped platinum-palladium alloy/dumbbell-like bismuth telluride heterostructures(denoted PtPdAu/BiTe)were synthesized using a visible-light-assisted strategy.The coupling alloy and interfacial effects of PtPdAu/BiTe significantly improved the performance and stability of both the ethanol oxidation reaction(EOR)and methanol oxidation reaction(MOR).Introducing a small amount of Au effectively enhanced the CO tolerance of PtPdAu/BiTe compared to dendritic platinum-palladium alloy/dumbbell-like bismuth telluride heterostructures.PtPdAu/BiTe exhibited mass activities of 31.5 and 13.3 A·mg_(Pt)^(-1)in EOR and MOR,respectively,which were 34.4 and 13.2 times higher than those of commercial Pt black,revealing efficient Pt atom utilization.In-situ Fourier transform infrared spectroscopy demonstrated complete 12e^(-)and 6e^(-)oxidation of ethanol and methanol on PtPdAu/BiTe.The PtPdAu/BiTe/C achieved mass peak power densities of 131 and 156 mW·mg_(Pt)^(-1),which were 2.4 and 2.2 times higher than those of Pt/C in practical direct ethanol fuel cell(DEFC)and direct methanol fuel cell(DMFC),respectively,highlighting their potential application in DEFC and DMFC.This study introduces an effective strategy for designing efficient and highly CO tolerant anodic electrocatalysts for practical DEFC and DMFC applications.展开更多
The embankment and bridge are the basic forms of railway lines.To date,no reports have addressed the optimal form to adopt when passing through sandy areas.Therefore,models of railway embankment and bridge were create...The embankment and bridge are the basic forms of railway lines.To date,no reports have addressed the optimal form to adopt when passing through sandy areas.Therefore,models of railway embankment and bridge were created,and wind tunnel experiments were conducted to compare the differences in wind speed,flow field,sand transport rate,and other wind–sand environmental effects of railway embankment and bridge.Results show that wind speed reduction areas in the upwind and downwind directions were observed for the railway embankment and bridge.In these areas,the extent and degree of wind speed reduction on the embankment were greater than those on the bridge.At the top of the embankment,especially on the windward slope shoulder,an obvious area of wind speed increase was observed.Similarly,a distinct area of wind speed increase was found between the top of the windward side slope shoulder and 3H downwind of the bridge.Within these regions,the range of wind speed increase on the embankment was smaller than that on the bridge,but the degree of increase was greater than that on the bridge.The range of variation in wind speed on the embankment was generally greater than that on the bridge.The wind–sand flow field around the embankment exhibited greater variability than that around the bridge.Moreover,higher wind–sand flow passage rates on the embankment than on the bridge.This study aims to offer recommendations to assist in the route selection,surveying,and design of railways in sandy regions.展开更多
The anodic electrochemical ozone production(EOP)and the cathodic three-electron oxygen reduction reaction(3e^(-)ORR)are effective processes for generating active oxygen species(ROS).However,the activation of ozone(O_(...The anodic electrochemical ozone production(EOP)and the cathodic three-electron oxygen reduction reaction(3e^(-)ORR)are effective processes for generating active oxygen species(ROS).However,the activation of ozone(O_(3))by hydroxyl radical(OH)to form ROS poses significant challenges.The micelle balllike bimetallic La-Nb oxides(LNOx)have been developed as a bifunctional electrocatalyst for both the EOP and 3e^(-)ORR reactions.The LNO20 demonstrated a 9.8%of Faradaic efficiency(FE)in O_(3)production and a transfer number of 2.8 electrons in the 3e^(-)ORR.Theoretical calculations support the notion that the five-membered ring mechanism in LNO20 facilitates O_(3)production.Additionally,the incorporation of La provides active sites that enhance the activation of hydrogen peroxide(^(*)H_(2)O_(2))and the generation of OH.This innovative approach synergistically integrates EOP and 3e^(-)ORR,enhancing the activation of O_(3)to produce ROS,demonstrating exceptional efficacy in the degradation of organic pollutants and antimicrobial activity.The study paves the way for designing advanced electrocatalysts for EOP and 3e^(-)ORR and offers insights into utilizing electrochemical method to support other antibacterial strategies.展开更多
With the rapid development of 5G technology and the interconnection of industrial production,electro-magnetic pollution has become a serious problem.Achieving lightweight and controllable loads of ab-sorbers while obt...With the rapid development of 5G technology and the interconnection of industrial production,electro-magnetic pollution has become a serious problem.Achieving lightweight and controllable loads of ab-sorbers while obtaining corrosion-resistant absorbers with high electromagnetic response properties is still considered a huge challenge.In this work,carbon fiber with a multichannel hollow structure is ob-tained by PAN/PS hybrid electrospinning and subsequent high-temperature roasting process.The spatial structure inside the carbon fiber plays an active role in optimizing the impedance matching character-istics of the absorber.In addition,bimetallic metal-organic frameworks(MOFs)derivatives are obtained by a precisely controlled ion exchange as well as a high-temperature gas-phase selenization process.The resulting introduction of a non-homogeneous interface induces interfacial polarization and improves the absorption behavior of the absorber.The analysis of the experimental results shows that the electro-magnetic wave(EMW)absorption performance can be effectively enhanced due to the mechanisms of interface polarization and dipole polarization.The prepared NiSe/ZnSe/MHCFs composite can obtain ex-cellent EMW absorption properties in C,X,and Ku bands by adjusting the thickness.Structural design and component modulation play a crucial role in realizing the strong absorption and wide bandwidth of the absorber.Radar cross-section calculations indicate that NiSe/ZnSe/MHCFs have tremendous potential in practical military stealth technology.And the prepared composite coating can provide periodic corrosion resistance to Q235 steel sheet when dealing with complex and extreme environments.展开更多
Soil cadmium pollution has increasingly become a serious problem for crop production,which drastically attenuates plant growth and food safety.Although N6-methyladenosine(m^(6)A)methylation is crucial for plant respon...Soil cadmium pollution has increasingly become a serious problem for crop production,which drastically attenuates plant growth and food safety.Although N6-methyladenosine(m^(6)A)methylation is crucial for plant response to various stresses,the regulatory mechanism underlying m^(6)A modification during cadmium(Cd)stress remains unclear.This study investigated the physiological responses,transcriptome-wide m^(6)A methylome,and proteome changes in tomato roots exposed to 50 μmol·L^(-1)CdCl2.Excess Cd restricted plant growth,altered the antioxidant system and disrupted mineral nutrient absorption.We identified a negative correlation between m^(6)A levels and gene transcription for that 150 out of 198 differentially expressed genes(DEGs)were hypomethylated but mRNA up-regulated.Cd stress also enhanced translational efficiency,particularly for differentially abundant proteins(DAPs).Kyoto Encyclopedia of Genes and Genomes(KEGG)analysis revealed that differentially m^(6)A modified genes(DMGs),DEGs,and DAPs were commonly enriched in phenylpropanoid biosynthesis,glutathione metabolism,and ABC transporters,reflecting cell wall barriers,chelation,and transport of Cd,respectively.Finally,we confirmed the Cd-transport activity of eight putative metal transporters identified in DMGs,DEGs,or DAPs by yeast complementaion experiments,and pharmacologically investigated the effect of m^(6)A modification on their expression.Treatment with the m^(6)A methylation inhibitor 3-deazaneplanocin A(3-DA)reduced SlIRT1/2 expression and increased SlNRAMP3/SlZIP4 expression,while the m^(6)A demethylase inhibitor meclofenamic acid(MA)treatment decreased SlNRAMP3 expression but elevated SlIRT2 expression under Cd stress.Our findings provide novel insights into the interplay between m^(6)A modification,transcription,and translation under Cd stress and the associated plant stress response.展开更多
The development of next-generation electromagnetic wave(EMW)absorbers requires a shift in interface design.By employing hierarchical work function programming,we propose an approach to tune interfacial polarization dy...The development of next-generation electromagnetic wave(EMW)absorbers requires a shift in interface design.By employing hierarchical work function programming,we propose an approach to tune interfacial polarization dynamics.This method utilizes multi-gradient work functions to guide carrier migration and polarization effectively,thereby enhancing energy dissipation under alternating electromagnetic fields.Here,we constructed a 1T/2H-MoS_(2)/PPy/VS_(2) composite absorber with integrated gradient interfaces.The composite achieved a powerful absorption(RLmin)of-58.59 dB at 2.3 mm,and an effective absorption bandwidth(EAB)of 7.44 GHz at 2.5 mm,demonstrating improved broadband absorption.Radar cross-section(RCS)simulations show an EMW loss of-7.2 dB m^(2) at 0°,highlighting its potential for stealth and communication applications.This study introduces hierarchical work function programming as a promising strategy in EMW absorber design,contributing to advancements in material performance and functionality.展开更多
Dispersing metals from nanoparticles to clusters is often achieved using ligand protection methods,which exhibit unique properties such as suppressing structure-sensitive side reactions.However,this method is limited ...Dispersing metals from nanoparticles to clusters is often achieved using ligand protection methods,which exhibit unique properties such as suppressing structure-sensitive side reactions.However,this method is limited by the use of different metal precursor salts corresponding to different ligands.An alternative approach,the ion exchange(IE)method,can overcome this limitation to some extent.Nevertheless,there is still an urgent need to address the stabilization of metals(especially precious metals)by using IE method.Here,we reported a Pt cluster catalyst prepared mainly by anchoring Pt atoms via O located near the framework Zn in zincosilicate zeolites and riveted by zeolite surface rings after reduction(reduced Pt/Zn-3-IE).The catalyst can achieve an initial propane conversion of 26%in a pure propane atmosphere at 550℃and shows little deactivation even after 7.5 d of operation.Moreover,the alteration of catalyst by the introduction of framework Zn was also highlighted and interpreted.展开更多
An effective cation-exchange chromatographic method for lysozyme isolation from chicken egg white is presented, using supermacroporous cryogel grafted with sulfo functional groups. The chromatographic processes were c...An effective cation-exchange chromatographic method for lysozyme isolation from chicken egg white is presented, using supermacroporous cryogel grafted with sulfo functional groups. The chromatographic processes were carried out by one-step and sequential elution, respectively. Sodium phosphate buffer （pH 7.8） containing different concentrations of NaC1 is used as elution agent. The corresponding breakthrough characteristics and elution behaviors in the cryogel bed were investigated and analyzed. Purity of lysozyme in the elution effluent was assayed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis （SDS-PAGE）. The maximum purity of the obtained lysozyme was about 96%, and the cryogel is demonstrated as a potential separation medium for purification of high-purit lysozyme from chicken egg white.展开更多
The origin, age and evolution of the Precambrian metamorphic basement of southern China provide useful insights into early crustal development. Here, we present new laser ablation-inductively coupled plasma-mass spect...The origin, age and evolution of the Precambrian metamorphic basement of southern China provide useful insights into early crustal development. Here, we present new laser ablation-inductively coupled plasma-mass spectrometry （LA-ICP-MS） U-Pb age data for detrital zircons from five samples of the Precambrian metamorphic basement of the Xiangshan uranium orefield. Two of these samples, from the northern Xiangshan volcanic basin, yielded a total of 140 U-Pb ages that cluster within the Neoproterozoic （773-963 Ma; 79.3% of data points）, with the rest being scattered through the Paleoproterozoic and Mesoproterozoic, along with a single Archean age. These ages indicate that this basement material is associated with the Cathaysia Block. In comparison, the 172 concordant ages from the other three samples from the southern part of the Xiangshan volcanic basin cluster within the Neoproterozoic （767-944 Ma; 59.8%） as well as the Proterozoic （37.8%） and the Archean （2502-2712 Ma; 14.5%）. These samples are also free of zircons with Grenvillian ages, indicating that these units are associated with the southeastern Yangtze Block. Combining these data with the geochemistry of these units, which suggests that the metamorphosed sedimentary rocks within the northern and southern parts of the Xiangshan basin have a common component from a magmatic island arc that formed during the early Neoproterozoic, we infer that the basin was located along the boundary between the Cathaysian and Yangtze blocks. In addition, the zircons within the samples from the southern and northern parts of the Xiangshan basin show different pre-Neoproterozoic （963 Ma） age populations but similar post- Neoproterozoic zircon populations, indicating that the amalgamation of the Cathaysian and Yangtze blocks occurred after the Neoproterozoic （960 Ma）, with magmatism peaking at 830 Ma and rifting starting at -770 Ma, leading to the subsequent deposition （from bottom to top） of the Shenshan, Kuli, and Shangshi formations.展开更多
Acoustic Emission(AE)waveforms contain information on microscopic structural features that can be related with damage of coal rock masses.In this paper,the Hilbert-Huang transform(HHT)method is used to obtain detailed...Acoustic Emission(AE)waveforms contain information on microscopic structural features that can be related with damage of coal rock masses.In this paper,the Hilbert-Huang transform(HHT)method is used to obtain detailed structural characteristics of coal rock masses associated with damage,at different loading stages,from the analyses of the characteristics of AE waveforms.The results show that the HHT method can be used to decompose the target waveform into multiple intrinsic mode function(IMF)components,with the energy mainly concentrated in the c1−c4 IMF components,where the c1 component has the highest frequency and the largest amount of energy.As the loading continues,the proportion of energy occupied by the low-frequency IMF component shows an increasing trend.In the initial compaction stage,the Hilbert marginal spectrum is mainly concentrated in the low frequency range of 0−40 kHz.The plastic deformation stage is associated to energy accumulation in the frequency range of 0−25 kHz and 200−350 kHz,while the instability damage stage is mainly concentrated in the frequency range of 0−25 kHz.At 20 kHz,the instability damage reaches its maximum value.There is a relatively clear instantaneous energy peak at each stage,albeit being more distinct at the beginning and at the end of the compaction phase.Since the effective duration of the waveform is short,its resulting energy is small,and so there is a relatively high value from the instantaneous energy peak.The waveform lasts a relatively long time after the peak that coincides with failure,which is the period where the waveform reaches its maximum energy level.The Hilbert three-dimensional energy spectrum is generally zero in the region where the real energy is zero.In addition,its energy spectrum is intermittent rather than continuous.It is therefore consistent with the characteristics of the several dynamic ranges mentioned above,and it indicates more clearly the low-frequency energy concentration in the critical stage of instability failure.This study well reflects the response law of geophysical signals in the process of coal rock instability and failure,providing a basis for monitoring coal rock dynamic disasters.展开更多
Aconite is a valuable drug and also a toxic material, which can be used only after detoxification processing. Although traditional processing methods can achieve detoxification effect as desired, there are some obviou...Aconite is a valuable drug and also a toxic material, which can be used only after detoxification processing. Although traditional processing methods can achieve detoxification effect as desired, there are some obvious drawbacks, including a significant loss of alkaloids and poor quality consistency. It is thus necessary to develop a new detoxification approach. In the present study, we designed a novel one-step detoxification approach by quickly drying fresh-cut aconite particles. In order to evaluate the technical advantages, the contents of mesaconitine, aconitine, hypaconitine, benzoylmesaconine, benzoylaconine, benzoylhypaconine, neoline, fuziline, songorine, and talatisamine were determined using HPLC and UHPLC/Q-TOF-MS. Multivariate analysis methods, such as Clustering analysis and Principle component analysis, were applied to determine the quality differences between samples. Our results showed that traditional processes could reduce toxicity as desired, but also led to more than 85.2% alkaloids loss. However, our novel one-step method was capable of achieving virtually the same detoxification effect, with only an approximately 30% alkaloids loss. Cluster analysis and Principal component analysis analyses suggested that Shengfupian and the novel products were significantly different from various traditional products. Acute toxicity testing showed that the novel products achieved a good detoxification effect, with its maximum tolerated dose being equivalent to 20 times of adult dosage. And cardiac effect testing also showed that the activity of the novel products was stronger than that of traditional products. Moreover, particles specification greatly improved the quality consistency of the novel products, which was immensely superior to the traditional products. These results would help guide the rational optimization of aconite processing technologies, providing better drugs for clinical treatment.展开更多
In this work, a series of MIL-101-SO3H（x） polymeric materials were prepared and further used for the first time as efficient heterogeneous catalysts for the conversion of fructose-based carbohydrates into 5-ethoxyme...In this work, a series of MIL-101-SO3H（x） polymeric materials were prepared and further used for the first time as efficient heterogeneous catalysts for the conversion of fructose-based carbohydrates into 5-ethoxymethylfurfural（EMF） in a renewable mixed solvent system consisting of ethanol and tetrahydrofuran（THF）. The influence of –SO3H content on the acidity as well as on the catalytic activity of the porous coordination polymers in EMF production was also studied. High EMF yields of 67.7% and 54.2% could be successively obtained from fructose and inulin in the presence of MIL-101-SO;H（100） at 130 °C for 15 h.The catalyst could be reused for five times without significant loss of its activity and the recovery process was facile and simple. This work provides a new platform by application of porous coordination polymers（PCPs） for the production of the potential liquid fuel molecule EMF from biomass in a sustainable solvent system.展开更多
Plant virus disease is one of the major causes of biological disasters in agriculture worldwide. Given the complexity of transmission media and plant disease infection mechanisms, the prevention and control of plant v...Plant virus disease is one of the major causes of biological disasters in agriculture worldwide. Given the complexity of transmission media and plant disease infection mechanisms, the prevention and control of plant viral diseases is a great challenge, and an efficient green pesticide is urgently needed. For this reason, when developing candidate drug leads to regulate plant viruses, pesticide experts have focused on characteristics such as low pesticide resistance, eco-friendliness, and novel mechanism. Researchers have also theoretically investigated the molecular targets of viruses infecting agricultural crops. Antiviral screening models have been constructed based on these molecular targets, and the mechanisms of commercial drugs and high-activity compounds have been extensively investigated. After screening, some compounds have been applied in the field and found to have good commercial prospects; these drugs may be used to create new green antiviral pesticides to control plant viruses. This paper reviews the screening, mode of action, development and application of recently used plant-based antiviral agents.展开更多
Voluminous platinum-group mineral （PGM） inclusions including erlichmanite （Os,Ru）S2, laurite （Ru,Os）S2, and irarsite （Ir, Os,Ru,Rh）AsS, as well as native osmium Os（Ir） and inclusions of base metal sulphides ...Voluminous platinum-group mineral （PGM） inclusions including erlichmanite （Os,Ru）S2, laurite （Ru,Os）S2, and irarsite （Ir, Os,Ru,Rh）AsS, as well as native osmium Os（Ir） and inclusions of base metal sulphides （BMS）, including millerite （NiS）, heazlewoodite （NiaS2）, covellite （CuS） and digenite （Cu3S2）, accompanied by native iron, have been identified in chromitites of the Zedang ophiolite, Tibet. The PGMs occur as both inclusions in magnesiochromite grains and as small interstitial granules between them; most are less than 10 ~m in size and vary in shape from euhedral to anhedral. They occur either as single or composite （biphase or polyphase） grains composed solely of PGM, or PGM associated with silicate grains. Os-, Ir-, and Ru-rich PGMs are the common species and Pt-, Pd-, and Rh-rich varieties have not been identified. Sulfur fugacity and temperature appear to be the main factors that controlled the PGE mineralogy during crystallization of the host chromitite in the upper mantle. If the activity of chalcogenides （such as S, and As） is low, PGE clusters will remain suspended in the silicate melt until they can coalesce to form alloys. Under appropriate conditions of fS2 and fO2, PGE alloys might react with the melt to form sulfides-sulfarsenides. Thus, we suggest that the Os, Ir and Ru metallic clusters and alloys in the Zedang chromitites crystallized first under high temperature and low fS2, followed by crystallization of sulphides of the laurite-erlichmanite, solid-solution series as the magma cooled and fS2 increased. The abundance of primary BMS in the chromitites suggests that fS2 reached relatively high values during the final stages of magnesiochromite crystallization. The diversity of the PGE minerals, in combination with differences in the petrological characteristics of the magnesiochromites, suggest different degrees of partial melting, perhaps at different depths in the mantle. The estimated parental magma composition suggests formation in a suprasubduction zone environment, perhaps in a forearc.展开更多
The coal mining process is afected by various water sources such as groundwater and coal seam water injection.Understanding the dynamic mechanical parameters of water-immersed coal is helpful for coalmine safe product...The coal mining process is afected by various water sources such as groundwater and coal seam water injection.Understanding the dynamic mechanical parameters of water-immersed coal is helpful for coalmine safe production.The impact compression tests were performed on coal with diferent moisture contents by using theϕ50 mm Split Hopkinson Pressure Bar(SHPB)experimental system,and the dynamic characteristics and energy loss laws of water-immersed coal with diferent compositions and water contents were analyzed.Through analysis and discussion,it is found that:(1)When the moisture content of the coal sample is 0%,30%,60%,the stress,strain rate and energy frst increase and then decrease with time.(2)When the moisture content of the coal sample increases from 30%to 60%,the stress“plateau”of the coal sample becomes more obvious,resulting in an increase in the compressive stress stage and a decrease in the expansion stress stage.(3)The increase of moisture content of the coal sample will afect its impact deformation and failure mode.When the moisture content is 60%,the incident rod end and the transmission rod end of the coal sample will have obvious compression failure,and the middle part of the coal sample will also experience expansion and deformation.(4)The coal composition ratio suitable for the coal immersion softening impact experiment is optimized.展开更多
Oxygen evolution from water driven by electrocatalysis or photocatalysis poses a significant challenge as it requires the use of efficient electro-/photo-catalysts to drive the four-electron oxygen evolution reaction(...Oxygen evolution from water driven by electrocatalysis or photocatalysis poses a significant challenge as it requires the use of efficient electro-/photo-catalysts to drive the four-electron oxygen evolution reaction(OER).Herein,we report the development of an effective strategy for the in situ chemical transformation of Fe-based bimetallic MIL-88 metal-organic frameworks(MOFs)into corresponding bimetallic hydroxides,which are composed of amorphous ultrasmall nanoparticles and afford an abundance of catalytically active sites.Optimized MOF-derived NiFe-OH-0.75 catalyst coated on glassy carbon electrodes achieved a current density of 10 mA cm^(-2)in the electrocatalytic OER with a small overpotential of 270 mV,which could be decreased to 235 mV when loading the catalysts on a nickel foam substrate.Moreover,these MOF-derived Fe-based bimetallic hydroxides can be used as efficient cocatalysts when combined with suitable photosensitizers for photocatalytic water oxidation.展开更多
To better retain useful weak low-frequency magnetotelluric(MT)signals with strong interference during MT data processing,we propose a SVM-CEEMDWT based MT data signal-noise separation method,which extracts the weak MT...To better retain useful weak low-frequency magnetotelluric(MT)signals with strong interference during MT data processing,we propose a SVM-CEEMDWT based MT data signal-noise separation method,which extracts the weak MT signal affected by strong interference.First,the approximate entropy,fuzzy entropy,sample entropy,and Lempel-Ziv(LZ)complexity are extracted from the magnetotelluric data.Then,four robust parameters are used as the inputs to the support vector machine(SVM)to train the sample library and build a model based on the different complexity of signals.Based on this model,we can only consider time series with strong interference when using the complementary ensemble empirical mode decomposition(CEEMD)and wavelet threshold(WT)for noise suppression.Simulation results suggest that the SVM based on the robust parameters can distinguish the time periods with strong interference well before noise suppression.Compared with the CEEMD WT,the proposed SVM-CEEMDWT method retains more low-frequency low-variability information,and the apparent resistivity curve is smoother and more continuous.Moreover,the results better reflect the deep electrical structure in the field.展开更多
基金supported by the National Key R&D Program of China(2021YFA1500900)National Natural Science Foundation of China(U21A20298,22141001).
文摘Machine learning(ML)integrated with density functional theory(DFT)calculations have recently been used to accelerate the design and discovery of single-atom catalysts(SACs)by establishing deep structure–activity relationships.The traditional ML models are always difficult to identify the structural differences among the single-atom systems with different modification methods,leading to the limitation of the potential application range.Aiming to the structural properties of several typical two-dimensional MA_(2)Z_(4)-based single-atom systems(bare MA_(2)Z_(4) and metal single-atom doped/supported MA_(2)Z_(4)),an improved crystal graph convolutional neural network(CGCNN)classification model was employed,instead of the traditional machine learning regression model,to address the challenge of incompatibility in the studied systems.The CGCNN model was optimized using crystal graph representation in which the geometric configuration was divided into active layer,surface layer,and bulk layer(ASB-GCNN).Through ML and DFT calculations,five potential single-atom hydrogen evolution reaction(HER)catalysts were screened from chemical space of 600 MA_(2)Z_(4)-based materials,especially V_(1)/HfSn_(2)N_(4)(S)with high stability and activity(Δ_(GH*)is 0.06 eV).Further projected density of states(pDOS)analysis in combination with the wave function analysis of the SAC-H bond revealed that the SAC-dz^(2)orbital coincided with the H-s orbital around the energy level of−2.50 eV,and orbital analysis confirmed the formation ofσbonds.This study provides an efficient multistep screening design framework of metal single-atom catalyst for HER systems with similar two-dimensional supports but different geometric configurations.
文摘Dispersing metals from nanoparticles into clusters or single atoms often exhibits unique properties such as the inhibition of structure-sensitive side reactions.Here,we reported the use of ion exchange(IE)methods and direct hydrogen reduction to achieve high dispersion of Co species on zincosilicate.The obtained 2Co/Zn-4-IE catalyst achieved an initial propane conversion of 41.4%at a temperature of 550℃in a 25%propane and 75%nitrogen atmosphere for propane dehydrogenation.Visualization of the presence of Co species within specific rings(alpha-α,beta-βand delta-δ)was obtained by aberration-corrected scanning transmission electron microscopy.A series of Fourier transform infrared spectra confirmed the anchoring of Co by specific hydroxyl groups in zincosilicate and the specific coordination environment of Co and its presence in the rings essentially as a single site.The framework Zn for the modulation of the microenvironment and the presence of Co species as Lewis acid active sites(Co-O4)was also supported by density functional theory calculations.
基金financially supported by National Natural Science Foundation of China(Nos.22138011,22108106 and 22108108)China Postdoctoral Science Foundation(Nos.2022M721380 and 2020M680065)Hong Kong Scholar Program(XJ2021021).
文摘CO_(2) photoreduction into carbon-based chemicals has been considered as an appropriate way to alleviate the energy issue and greenhouse effect.Herein,the 5,10,15,20-tetra(4-carboxyphenyl)porphyrin cobalt(II)(CoTCPP)has been integrated with BiOBr microspheres and formed the CoTCPP/BiOBr composite.The as-prepared CoTCPP/BiOBr-2 composite shows optimized photocatalytic performance for CO_(2) conversion into CO and CH_(4) upon irradiation with 300 W Xe lamp,which is 2.03 and 2.58 times compared to that of BiOBr,respectively.The introduced CoTCPP significantly enhanced light absorption properties,promoted rapid separation of photogenerated carriers and boosted the chemisorption of CO_(2) molecules.The metal Co^(2+) at the center of the porphyrin molecules also acts as adsorption center for CO_(2) molecules,accelerating the CO_(2) conversion into CO and CH_(4).The possible mechanism of CO_(2) photoreduction was explored by in-situ FT-IR spectra.This work offers a new possibility for the preparation of advanced photocatalysts.
基金supported by the National Natural Science Foundation of China(No.22465009)the Education Department of Guizhou Province(No.2021312)the Foundation of Guizhou Province(No.2019-5666).
文摘Alloying and interface effects are effective strategies for enhancing the performance of electrocatalysts in energy-related devices.Herein,dendritic Au-doped platinum-palladium alloy/dumbbell-like bismuth telluride heterostructures(denoted PtPdAu/BiTe)were synthesized using a visible-light-assisted strategy.The coupling alloy and interfacial effects of PtPdAu/BiTe significantly improved the performance and stability of both the ethanol oxidation reaction(EOR)and methanol oxidation reaction(MOR).Introducing a small amount of Au effectively enhanced the CO tolerance of PtPdAu/BiTe compared to dendritic platinum-palladium alloy/dumbbell-like bismuth telluride heterostructures.PtPdAu/BiTe exhibited mass activities of 31.5 and 13.3 A·mg_(Pt)^(-1)in EOR and MOR,respectively,which were 34.4 and 13.2 times higher than those of commercial Pt black,revealing efficient Pt atom utilization.In-situ Fourier transform infrared spectroscopy demonstrated complete 12e^(-)and 6e^(-)oxidation of ethanol and methanol on PtPdAu/BiTe.The PtPdAu/BiTe/C achieved mass peak power densities of 131 and 156 mW·mg_(Pt)^(-1),which were 2.4 and 2.2 times higher than those of Pt/C in practical direct ethanol fuel cell(DEFC)and direct methanol fuel cell(DMFC),respectively,highlighting their potential application in DEFC and DMFC.This study introduces an effective strategy for designing efficient and highly CO tolerant anodic electrocatalysts for practical DEFC and DMFC applications.
基金supported by the National Natural Science Foundation of China(Grant Nos.42077448 and 42477505)the Western Young Scholars project of the Chinese Academy of Sciences of China(Grant No.xbzglzb2022024)+2 种基金the Natural Science Foundation of Gansu Province for Distinguished Young Scholars(Grant No.22JR5RA049)the Ordos Science and Technology Plan(Grant No.2021EEDSCXQDFZ013)the Longyuan Youth Talent Project of Gansu Province(Grant No.E339020101)。
文摘The embankment and bridge are the basic forms of railway lines.To date,no reports have addressed the optimal form to adopt when passing through sandy areas.Therefore,models of railway embankment and bridge were created,and wind tunnel experiments were conducted to compare the differences in wind speed,flow field,sand transport rate,and other wind–sand environmental effects of railway embankment and bridge.Results show that wind speed reduction areas in the upwind and downwind directions were observed for the railway embankment and bridge.In these areas,the extent and degree of wind speed reduction on the embankment were greater than those on the bridge.At the top of the embankment,especially on the windward slope shoulder,an obvious area of wind speed increase was observed.Similarly,a distinct area of wind speed increase was found between the top of the windward side slope shoulder and 3H downwind of the bridge.Within these regions,the range of wind speed increase on the embankment was smaller than that on the bridge,but the degree of increase was greater than that on the bridge.The range of variation in wind speed on the embankment was generally greater than that on the bridge.The wind–sand flow field around the embankment exhibited greater variability than that around the bridge.Moreover,higher wind–sand flow passage rates on the embankment than on the bridge.This study aims to offer recommendations to assist in the route selection,surveying,and design of railways in sandy regions.
基金the financial support from the National Key R&D Program of China(2022YFA1504200)the Zhejiang Provincial Natural Science Foundation(No.LR22B060003)+2 种基金the National Natural Science Foundation of China(22322810,22078293,22141001,and 22008211)the Fundamental Research Funds for the Provincial Universities of Zhejiang(RF-C2023004)the Midea Group-Zhejiang University of Technology Joint Development Funding(KYY-HX-20240263)。
文摘The anodic electrochemical ozone production(EOP)and the cathodic three-electron oxygen reduction reaction(3e^(-)ORR)are effective processes for generating active oxygen species(ROS).However,the activation of ozone(O_(3))by hydroxyl radical(OH)to form ROS poses significant challenges.The micelle balllike bimetallic La-Nb oxides(LNOx)have been developed as a bifunctional electrocatalyst for both the EOP and 3e^(-)ORR reactions.The LNO20 demonstrated a 9.8%of Faradaic efficiency(FE)in O_(3)production and a transfer number of 2.8 electrons in the 3e^(-)ORR.Theoretical calculations support the notion that the five-membered ring mechanism in LNO20 facilitates O_(3)production.Additionally,the incorporation of La provides active sites that enhance the activation of hydrogen peroxide(^(*)H_(2)O_(2))and the generation of OH.This innovative approach synergistically integrates EOP and 3e^(-)ORR,enhancing the activation of O_(3)to produce ROS,demonstrating exceptional efficacy in the degradation of organic pollutants and antimicrobial activity.The study paves the way for designing advanced electrocatalysts for EOP and 3e^(-)ORR and offers insights into utilizing electrochemical method to support other antibacterial strategies.
基金supported by the National Natural Sci-ence Foundation of China(Nos.52377026 and 52301192)Tais-han Scholars and Young Experts Program of Shandong Province(No.tsqn202103057)+4 种基金Postdoctoral Fellowship Program of CPSF(No.GZB20240327)Shandong Postdoctoral Science Foundation(No.SDCX-ZG-202400275)Qingdao Postdoctoral Application Re-search Project(No.QDBSH20240102023)China Postdoctoral Sci-ence Foundation(No.2024M751563)the Qingchuang Talents Induction Program of Shandong Higher Education Institution(Re-search and Innovation Team of Structural-Functional Polymer Com-posites).
文摘With the rapid development of 5G technology and the interconnection of industrial production,electro-magnetic pollution has become a serious problem.Achieving lightweight and controllable loads of ab-sorbers while obtaining corrosion-resistant absorbers with high electromagnetic response properties is still considered a huge challenge.In this work,carbon fiber with a multichannel hollow structure is ob-tained by PAN/PS hybrid electrospinning and subsequent high-temperature roasting process.The spatial structure inside the carbon fiber plays an active role in optimizing the impedance matching character-istics of the absorber.In addition,bimetallic metal-organic frameworks(MOFs)derivatives are obtained by a precisely controlled ion exchange as well as a high-temperature gas-phase selenization process.The resulting introduction of a non-homogeneous interface induces interfacial polarization and improves the absorption behavior of the absorber.The analysis of the experimental results shows that the electro-magnetic wave(EMW)absorption performance can be effectively enhanced due to the mechanisms of interface polarization and dipole polarization.The prepared NiSe/ZnSe/MHCFs composite can obtain ex-cellent EMW absorption properties in C,X,and Ku bands by adjusting the thickness.Structural design and component modulation play a crucial role in realizing the strong absorption and wide bandwidth of the absorber.Radar cross-section calculations indicate that NiSe/ZnSe/MHCFs have tremendous potential in practical military stealth technology.And the prepared composite coating can provide periodic corrosion resistance to Q235 steel sheet when dealing with complex and extreme environments.
基金supported by the National Natural Science Foundation of China(Grant No.32002113)the Natural Science Research Project of Jiangsu Higher Education Institutions(Grant No.19KJB210001)+7 种基金the Natural Science Foundation of Jiangsu Province(Grant No.BK20190958)the Key Research and Development Program of Zhejiang Province(Grant No.2021C02052)National Key Research and Development Program of China(Grant Nos.2018YFD1000800,2017YFE0114500)Zhejiang Provincial major Agricultural Science and Technology Projects of New Varieties Breeding(2021C02065)China Agriculture Research System of MOF and MARA(Grant No.CARS-23-G44)the Ministry of Science and Technology of the People’s Republic of China(Grant No.DL2022026004L)the National Natural Science Foundation of China(Grant No.31950410555)the Innovative Research Team(Science and Technology)in the University of Henan Province(Grant No.23IRTSTHN024).
文摘Soil cadmium pollution has increasingly become a serious problem for crop production,which drastically attenuates plant growth and food safety.Although N6-methyladenosine(m^(6)A)methylation is crucial for plant response to various stresses,the regulatory mechanism underlying m^(6)A modification during cadmium(Cd)stress remains unclear.This study investigated the physiological responses,transcriptome-wide m^(6)A methylome,and proteome changes in tomato roots exposed to 50 μmol·L^(-1)CdCl2.Excess Cd restricted plant growth,altered the antioxidant system and disrupted mineral nutrient absorption.We identified a negative correlation between m^(6)A levels and gene transcription for that 150 out of 198 differentially expressed genes(DEGs)were hypomethylated but mRNA up-regulated.Cd stress also enhanced translational efficiency,particularly for differentially abundant proteins(DAPs).Kyoto Encyclopedia of Genes and Genomes(KEGG)analysis revealed that differentially m^(6)A modified genes(DMGs),DEGs,and DAPs were commonly enriched in phenylpropanoid biosynthesis,glutathione metabolism,and ABC transporters,reflecting cell wall barriers,chelation,and transport of Cd,respectively.Finally,we confirmed the Cd-transport activity of eight putative metal transporters identified in DMGs,DEGs,or DAPs by yeast complementaion experiments,and pharmacologically investigated the effect of m^(6)A modification on their expression.Treatment with the m^(6)A methylation inhibitor 3-deazaneplanocin A(3-DA)reduced SlIRT1/2 expression and increased SlNRAMP3/SlZIP4 expression,while the m^(6)A demethylase inhibitor meclofenamic acid(MA)treatment decreased SlNRAMP3 expression but elevated SlIRT2 expression under Cd stress.Our findings provide novel insights into the interplay between m^(6)A modification,transcription,and translation under Cd stress and the associated plant stress response.
基金supported by the National Natural Science Foundation of China(Nos.22275156,52025132,21,621,091,52300138,22021001 and 22121001)the Fundamental Research Funds for the Central Universities of China(No.20720220019)+2 种基金the National Science Foundation of Fujian Province of China(No.2022J02059)the 111 Project(Nos.B17027,B16029)the New Cornerstone Science Foundation through the XPLORER PRIZE。
文摘The development of next-generation electromagnetic wave(EMW)absorbers requires a shift in interface design.By employing hierarchical work function programming,we propose an approach to tune interfacial polarization dynamics.This method utilizes multi-gradient work functions to guide carrier migration and polarization effectively,thereby enhancing energy dissipation under alternating electromagnetic fields.Here,we constructed a 1T/2H-MoS_(2)/PPy/VS_(2) composite absorber with integrated gradient interfaces.The composite achieved a powerful absorption(RLmin)of-58.59 dB at 2.3 mm,and an effective absorption bandwidth(EAB)of 7.44 GHz at 2.5 mm,demonstrating improved broadband absorption.Radar cross-section(RCS)simulations show an EMW loss of-7.2 dB m^(2) at 0°,highlighting its potential for stealth and communication applications.This study introduces hierarchical work function programming as a promising strategy in EMW absorber design,contributing to advancements in material performance and functionality.
文摘Dispersing metals from nanoparticles to clusters is often achieved using ligand protection methods,which exhibit unique properties such as suppressing structure-sensitive side reactions.However,this method is limited by the use of different metal precursor salts corresponding to different ligands.An alternative approach,the ion exchange(IE)method,can overcome this limitation to some extent.Nevertheless,there is still an urgent need to address the stabilization of metals(especially precious metals)by using IE method.Here,we reported a Pt cluster catalyst prepared mainly by anchoring Pt atoms via O located near the framework Zn in zincosilicate zeolites and riveted by zeolite surface rings after reduction(reduced Pt/Zn-3-IE).The catalyst can achieve an initial propane conversion of 26%in a pure propane atmosphere at 550℃and shows little deactivation even after 7.5 d of operation.Moreover,the alteration of catalyst by the introduction of framework Zn was also highlighted and interpreted.
基金Supported by the National lqatural Science Foundation of China （21036005, 20876145）, the Science and Technology Cooperation Project between China-Europe Country＇s Governments from the Ministry of Science and Technology of China （1017） and the Natural Science Foundation of Zhejiang Provincial （Y4080326）.
文摘An effective cation-exchange chromatographic method for lysozyme isolation from chicken egg white is presented, using supermacroporous cryogel grafted with sulfo functional groups. The chromatographic processes were carried out by one-step and sequential elution, respectively. Sodium phosphate buffer （pH 7.8） containing different concentrations of NaC1 is used as elution agent. The corresponding breakthrough characteristics and elution behaviors in the cryogel bed were investigated and analyzed. Purity of lysozyme in the elution effluent was assayed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis （SDS-PAGE）. The maximum purity of the obtained lysozyme was about 96%, and the cryogel is demonstrated as a potential separation medium for purification of high-purit lysozyme from chicken egg white.
基金financially supported by the National Natural Science Foundation of China(Grant No.41602069 and 41572185)the Fundamental Science on Radioactive Geology and Exploration Technology Laboratory(Grant No.RGET1402)+1 种基金the Natural Science Foundation of Jiangxi Province(Grant No.20171BAB213026)Science and technology research projectfrom the Education Department of Jiangxi Province(Grant No.GJJ150554)
文摘The origin, age and evolution of the Precambrian metamorphic basement of southern China provide useful insights into early crustal development. Here, we present new laser ablation-inductively coupled plasma-mass spectrometry （LA-ICP-MS） U-Pb age data for detrital zircons from five samples of the Precambrian metamorphic basement of the Xiangshan uranium orefield. Two of these samples, from the northern Xiangshan volcanic basin, yielded a total of 140 U-Pb ages that cluster within the Neoproterozoic （773-963 Ma; 79.3% of data points）, with the rest being scattered through the Paleoproterozoic and Mesoproterozoic, along with a single Archean age. These ages indicate that this basement material is associated with the Cathaysia Block. In comparison, the 172 concordant ages from the other three samples from the southern part of the Xiangshan volcanic basin cluster within the Neoproterozoic （767-944 Ma; 59.8%） as well as the Proterozoic （37.8%） and the Archean （2502-2712 Ma; 14.5%）. These samples are also free of zircons with Grenvillian ages, indicating that these units are associated with the southeastern Yangtze Block. Combining these data with the geochemistry of these units, which suggests that the metamorphosed sedimentary rocks within the northern and southern parts of the Xiangshan basin have a common component from a magmatic island arc that formed during the early Neoproterozoic, we infer that the basin was located along the boundary between the Cathaysian and Yangtze blocks. In addition, the zircons within the samples from the southern and northern parts of the Xiangshan basin show different pre-Neoproterozoic （963 Ma） age populations but similar post- Neoproterozoic zircon populations, indicating that the amalgamation of the Cathaysian and Yangtze blocks occurred after the Neoproterozoic （960 Ma）, with magmatism peaking at 830 Ma and rifting starting at -770 Ma, leading to the subsequent deposition （from bottom to top） of the Shenshan, Kuli, and Shangshi formations.
基金Projects(51904167, 51474134, 51774194) supported by the National Natural Science Foundation of ChinaProject(SKLCRSM19KF008) supported by the Research Fund of the State Key Laboratory of Coal Resources and Safe Mining,CUMT,China+5 种基金Project(cstc2019jcyj-bsh0041) supported by the Natural Science Foundation of Chongqing,ChinaProject(2011DA105287-BH201903) supported by the Postdoctoral ScienceFunded by State Key Laboratory of Coal Mine Disaster Dynamics and Control,ChinaProject(2019SDZY034-2) supported by the Key R&D plan of Shandong Province,ChinaProject(2020M670781) supported by the China Postdoctoral Science FoundationProject supported by the Taishan Scholars ProjectProject supported by the Taishan Scholar Talent Team Support Plan for Advantaged&Unique Discipline Areas,China
文摘Acoustic Emission(AE)waveforms contain information on microscopic structural features that can be related with damage of coal rock masses.In this paper,the Hilbert-Huang transform(HHT)method is used to obtain detailed structural characteristics of coal rock masses associated with damage,at different loading stages,from the analyses of the characteristics of AE waveforms.The results show that the HHT method can be used to decompose the target waveform into multiple intrinsic mode function(IMF)components,with the energy mainly concentrated in the c1−c4 IMF components,where the c1 component has the highest frequency and the largest amount of energy.As the loading continues,the proportion of energy occupied by the low-frequency IMF component shows an increasing trend.In the initial compaction stage,the Hilbert marginal spectrum is mainly concentrated in the low frequency range of 0−40 kHz.The plastic deformation stage is associated to energy accumulation in the frequency range of 0−25 kHz and 200−350 kHz,while the instability damage stage is mainly concentrated in the frequency range of 0−25 kHz.At 20 kHz,the instability damage reaches its maximum value.There is a relatively clear instantaneous energy peak at each stage,albeit being more distinct at the beginning and at the end of the compaction phase.Since the effective duration of the waveform is short,its resulting energy is small,and so there is a relatively high value from the instantaneous energy peak.The waveform lasts a relatively long time after the peak that coincides with failure,which is the period where the waveform reaches its maximum energy level.The Hilbert three-dimensional energy spectrum is generally zero in the region where the real energy is zero.In addition,its energy spectrum is intermittent rather than continuous.It is therefore consistent with the characteristics of the several dynamic ranges mentioned above,and it indicates more clearly the low-frequency energy concentration in the critical stage of instability failure.This study well reflects the response law of geophysical signals in the process of coal rock instability and failure,providing a basis for monitoring coal rock dynamic disasters.
基金supported by National Nature Science Fundation of China(Nos.81274026 and 81403115)
文摘Aconite is a valuable drug and also a toxic material, which can be used only after detoxification processing. Although traditional processing methods can achieve detoxification effect as desired, there are some obvious drawbacks, including a significant loss of alkaloids and poor quality consistency. It is thus necessary to develop a new detoxification approach. In the present study, we designed a novel one-step detoxification approach by quickly drying fresh-cut aconite particles. In order to evaluate the technical advantages, the contents of mesaconitine, aconitine, hypaconitine, benzoylmesaconine, benzoylaconine, benzoylhypaconine, neoline, fuziline, songorine, and talatisamine were determined using HPLC and UHPLC/Q-TOF-MS. Multivariate analysis methods, such as Clustering analysis and Principle component analysis, were applied to determine the quality differences between samples. Our results showed that traditional processes could reduce toxicity as desired, but also led to more than 85.2% alkaloids loss. However, our novel one-step method was capable of achieving virtually the same detoxification effect, with only an approximately 30% alkaloids loss. Cluster analysis and Principal component analysis analyses suggested that Shengfupian and the novel products were significantly different from various traditional products. Acute toxicity testing showed that the novel products achieved a good detoxification effect, with its maximum tolerated dose being equivalent to 20 times of adult dosage. And cardiac effect testing also showed that the activity of the novel products was stronger than that of traditional products. Moreover, particles specification greatly improved the quality consistency of the novel products, which was immensely superior to the traditional products. These results would help guide the rational optimization of aconite processing technologies, providing better drugs for clinical treatment.
基金financially supported by the Natural Science Foundation of China(no.21576059)the Key Technologies R&D Program(no.2011BAE06B02)+1 种基金the International Science&Technology Cooperation Program of China(2010DFB60840)the Science and Technology Project of Guizhou Province(nos.[2012]6012 and[2011]3016)
文摘In this work, a series of MIL-101-SO3H（x） polymeric materials were prepared and further used for the first time as efficient heterogeneous catalysts for the conversion of fructose-based carbohydrates into 5-ethoxymethylfurfural（EMF） in a renewable mixed solvent system consisting of ethanol and tetrahydrofuran（THF）. The influence of –SO3H content on the acidity as well as on the catalytic activity of the porous coordination polymers in EMF production was also studied. High EMF yields of 67.7% and 54.2% could be successively obtained from fructose and inulin in the presence of MIL-101-SO;H（100） at 130 °C for 15 h.The catalyst could be reused for five times without significant loss of its activity and the recovery process was facile and simple. This work provides a new platform by application of porous coordination polymers（PCPs） for the production of the potential liquid fuel molecule EMF from biomass in a sustainable solvent system.
基金supported by the National Natural Science Foundation of China (21132003, 31460460, 21502032 and 21732002)the Subsidy Project for Outstanding Key Laboratory of Guizhou Province in China (20154004)+1 种基金the Provincial University Cooperation Plan of Guizhou Province in China (20147001)the Collaborative Innovation Center for Natural Products and Biological Drugs of Yunnan, China
文摘Plant virus disease is one of the major causes of biological disasters in agriculture worldwide. Given the complexity of transmission media and plant disease infection mechanisms, the prevention and control of plant viral diseases is a great challenge, and an efficient green pesticide is urgently needed. For this reason, when developing candidate drug leads to regulate plant viruses, pesticide experts have focused on characteristics such as low pesticide resistance, eco-friendliness, and novel mechanism. Researchers have also theoretically investigated the molecular targets of viruses infecting agricultural crops. Antiviral screening models have been constructed based on these molecular targets, and the mechanisms of commercial drugs and high-activity compounds have been extensively investigated. After screening, some compounds have been applied in the field and found to have good commercial prospects; these drugs may be used to create new green antiviral pesticides to control plant viruses. This paper reviews the screening, mode of action, development and application of recently used plant-based antiviral agents.
基金financially supported by the National Natural Science Foundation of China (Grant No.41262002,40930313,41302052,41502062)National Industry Special Projects (Sino Probe-05-02)+2 种基金China Bureau of Geological Survey Projects (DD20160023-01)IGCP-649Institute of Geology, Chinese Academy of Geological Science (J1526)
文摘Voluminous platinum-group mineral （PGM） inclusions including erlichmanite （Os,Ru）S2, laurite （Ru,Os）S2, and irarsite （Ir, Os,Ru,Rh）AsS, as well as native osmium Os（Ir） and inclusions of base metal sulphides （BMS）, including millerite （NiS）, heazlewoodite （NiaS2）, covellite （CuS） and digenite （Cu3S2）, accompanied by native iron, have been identified in chromitites of the Zedang ophiolite, Tibet. The PGMs occur as both inclusions in magnesiochromite grains and as small interstitial granules between them; most are less than 10 ~m in size and vary in shape from euhedral to anhedral. They occur either as single or composite （biphase or polyphase） grains composed solely of PGM, or PGM associated with silicate grains. Os-, Ir-, and Ru-rich PGMs are the common species and Pt-, Pd-, and Rh-rich varieties have not been identified. Sulfur fugacity and temperature appear to be the main factors that controlled the PGE mineralogy during crystallization of the host chromitite in the upper mantle. If the activity of chalcogenides （such as S, and As） is low, PGE clusters will remain suspended in the silicate melt until they can coalesce to form alloys. Under appropriate conditions of fS2 and fO2, PGE alloys might react with the melt to form sulfides-sulfarsenides. Thus, we suggest that the Os, Ir and Ru metallic clusters and alloys in the Zedang chromitites crystallized first under high temperature and low fS2, followed by crystallization of sulphides of the laurite-erlichmanite, solid-solution series as the magma cooled and fS2 increased. The abundance of primary BMS in the chromitites suggests that fS2 reached relatively high values during the final stages of magnesiochromite crystallization. The diversity of the PGE minerals, in combination with differences in the petrological characteristics of the magnesiochromites, suggest different degrees of partial melting, perhaps at different depths in the mantle. The estimated parental magma composition suggests formation in a suprasubduction zone environment, perhaps in a forearc.
基金This research was funded by the National Natural Science Foundation of China(51974176,51934004)ShandongProvince Natural Science Foundation of Outstanding Youth Fund(ZR2020JQ22)+1 种基金Shandong Province Colleges and Universities Youth Innovation and Technology Support Program(2019KJH006)Taishan Scholars Project(TS20190935).
文摘The coal mining process is afected by various water sources such as groundwater and coal seam water injection.Understanding the dynamic mechanical parameters of water-immersed coal is helpful for coalmine safe production.The impact compression tests were performed on coal with diferent moisture contents by using theϕ50 mm Split Hopkinson Pressure Bar(SHPB)experimental system,and the dynamic characteristics and energy loss laws of water-immersed coal with diferent compositions and water contents were analyzed.Through analysis and discussion,it is found that:(1)When the moisture content of the coal sample is 0%,30%,60%,the stress,strain rate and energy frst increase and then decrease with time.(2)When the moisture content of the coal sample increases from 30%to 60%,the stress“plateau”of the coal sample becomes more obvious,resulting in an increase in the compressive stress stage and a decrease in the expansion stress stage.(3)The increase of moisture content of the coal sample will afect its impact deformation and failure mode.When the moisture content is 60%,the incident rod end and the transmission rod end of the coal sample will have obvious compression failure,and the middle part of the coal sample will also experience expansion and deformation.(4)The coal composition ratio suitable for the coal immersion softening impact experiment is optimized.
文摘Oxygen evolution from water driven by electrocatalysis or photocatalysis poses a significant challenge as it requires the use of efficient electro-/photo-catalysts to drive the four-electron oxygen evolution reaction(OER).Herein,we report the development of an effective strategy for the in situ chemical transformation of Fe-based bimetallic MIL-88 metal-organic frameworks(MOFs)into corresponding bimetallic hydroxides,which are composed of amorphous ultrasmall nanoparticles and afford an abundance of catalytically active sites.Optimized MOF-derived NiFe-OH-0.75 catalyst coated on glassy carbon electrodes achieved a current density of 10 mA cm^(-2)in the electrocatalytic OER with a small overpotential of 270 mV,which could be decreased to 235 mV when loading the catalysts on a nickel foam substrate.Moreover,these MOF-derived Fe-based bimetallic hydroxides can be used as efficient cocatalysts when combined with suitable photosensitizers for photocatalytic water oxidation.
基金funded by the National Key R&D Program of China(No.2018YFC0603202)the National Natural Science Foundation of China(No.41404111)+1 种基金Natural Science Foundation of Hunan Province(No.2018JJ2258)Hunan Provincial Science and Technology Project Foundation(No.2018TP1018)
文摘To better retain useful weak low-frequency magnetotelluric(MT)signals with strong interference during MT data processing,we propose a SVM-CEEMDWT based MT data signal-noise separation method,which extracts the weak MT signal affected by strong interference.First,the approximate entropy,fuzzy entropy,sample entropy,and Lempel-Ziv(LZ)complexity are extracted from the magnetotelluric data.Then,four robust parameters are used as the inputs to the support vector machine(SVM)to train the sample library and build a model based on the different complexity of signals.Based on this model,we can only consider time series with strong interference when using the complementary ensemble empirical mode decomposition(CEEMD)and wavelet threshold(WT)for noise suppression.Simulation results suggest that the SVM based on the robust parameters can distinguish the time periods with strong interference well before noise suppression.Compared with the CEEMD WT,the proposed SVM-CEEMDWT method retains more low-frequency low-variability information,and the apparent resistivity curve is smoother and more continuous.Moreover,the results better reflect the deep electrical structure in the field.
