The Chinese Hα Solar Explorer(CHASE), dubbed “Xihe”—Goddess of the Sun, was launched on October 14, 2021 as the first solar space mission of China National Space Administration(CNSA). The CHASE mission is designed...The Chinese Hα Solar Explorer(CHASE), dubbed “Xihe”—Goddess of the Sun, was launched on October 14, 2021 as the first solar space mission of China National Space Administration(CNSA). The CHASE mission is designed to test a newly developed satellite platform and to acquire the spectroscopic observations in the Hα waveband. The Hα Imaging Spectrograph(HIS)is the scientific payload of the CHASE satellite. It consists of two observational modes: raster scanning mode and continuum imaging mode. The raster scanning mode obtains full-Sun or region-of-interest spectral images from 6559.7 to 6565.9 ? and from 6567.8 to 6570.6 ? with 0.024 ? pixel spectral resolution and 1 min temporal resolution. The continuum imaging mode obtains photospheric images in continuum around 6689 ? with the full width at half maximum of 13.4 ?. The CHASE mission will advance our understanding of the dynamics of solar activity in the photosphere and chromosphere. In this paper, we present an overview of the CHASE mission including the scientific objectives, HIS instrument overview, data calibration flow, and first results of on-orbit observations.展开更多
The Tunggurian Age was nominated in 1984, and the Second National Commission on Stratigraphy of China formally suggested establishing the corresponding chronostratigraphic unit, the Tunggurian Stage, based on the Tung...The Tunggurian Age was nominated in 1984, and the Second National Commission on Stratigraphy of China formally suggested establishing the corresponding chronostratigraphic unit, the Tunggurian Stage, based on the Tunggurian Age in 1999. The name of this stage comes from a lithostratigraphic unit, the Tunggur Formation, and the stratotype section is located at the Tunggur tableland, 15 km southeast of Saihan Gobi Township, Sonid Left Banner, Inner Mongolia. The Tunggurian Age is correlated to the Astaracian of the European land mammal ages, and they share the same definition of the lower boundary at the base of the paleomagnetic Chron C5Bn.1r with an age of 15.0 Ma. In the Tairum Nor section on the southeastern edge of the Tunggur tableland, this boundary is situated within the successive deposits of reddish-brown massive mudstone of the lower part of the Tunggur Formation, with a distance of 7.6 m from the base of the grayish-white sandstones in the middle part of the section. The Tunggurian is approximately correlated to the upper part of the marine Langhian and the marine Serravallian in the International Stratigraphical Chart. The Tunggurian Stage includes two Neogene mammal faunal units, i.e. NMU 6 （MN 6） and NMU 7 （MN 7/8）. The Tairnm Nor fauna from the Talrnm Nor section corresponds to NMU 6, and the Tunggur fauna （senso stricto） from the localities on the northwestern edge of the Tunggur tableland, such as Platybelodon Quarry, Wolf Camp and Moergen, corresponds to NMU 7. Among the Middle Miocene mammalian faunas in China, the Laogou fauna from the Linxia Basin, Gansu, the Quantougou fauna from the Lanzhou Basin, Gansu, the Halamagai fauna from the northern Junggar Basin, Xinjiang, and the Dingjiaergou fauna from Tongxin, Ningxia correspond to NMU 6.展开更多
A field-scale aged refuse （AR） biofilter constructed in Shanghai Refuse Landfill, containing about 7000 m^3 aged refuse inside, was evaluated for its performance in the treatment of landfill leachate. This AR biofil...A field-scale aged refuse （AR） biofilter constructed in Shanghai Refuse Landfill, containing about 7000 m^3 aged refuse inside, was evaluated for its performance in the treatment of landfill leachate. This AR biofilter can be divided into three stages and can manage 50 m^3 landfill leachate per day. The physical, chemical, and biological characteristics of AR were analyzed for evaluating the AR biofilter as leachate treatment host. The results revealed that over 87.8%-96.2% of COD and 96.9%-99.4% of ammonia nitrogen were removed by the three-stage AR biofilter when the infiuent leachate COD and ammonia nitrogen concentration were in the range 5478-10842 mg/L and 811-1582 mg/L, respectively. The final effluent was inodorous and pale yellow with COD and ammonia nitrogen below 267-1020 mg/L and 6-45 mg/L, respectively. The three-stage AR biofilter had efficient nitrification but relative poor denitrification capacity with a total nitrogen （TN） removal of 58%-73%. The external temperature of AR biofilter did not influence the total ammonia nitrogen removal significantly. It was concluded that the scale-up AR biofilter can work very well and can be a promising technology for the treatment of landfill leachate.展开更多
This paper discussed theory and methodologies of debris-flow risk assessment and established an implementation process according to indicators of debris-flow hazard degree, vulnerability, risk degree, etc. Among these...This paper discussed theory and methodologies of debris-flow risk assessment and established an implementation process according to indicators of debris-flow hazard degree, vulnerability, risk degree, etc. Among these methodologies, historical and potential hazard degree was comprehensively considered into hazard assessment and hazard index was presented to indicate the debris-flow hazard degree. Regarding debris-flow vulnerability assessment, its statistical data and calculating procedure were based on the hazard-degree regionalization instead of administrative divisions, which improved the assessing scientificity and precision. These quantitative methodologies integrated with Geography Information System （GIS） were applied to the risk assessment of debris flows in the upper reach of Yangtze River. Its results were in substantial agreement on investigation data and the actual distribution of debris flows, which showed that these principles and methodologies were reasonable and feasible and can provide basis or reference for debris-flow risk assessment and disaster management.展开更多
Approximately 7000 m^3 of aged refuse （AR） with a placement of over eight years was excavated from Shanghai Refuse Landfill, the largest landfill in China, and used for the construction of a two-stage bioreactor （A...Approximately 7000 m^3 of aged refuse （AR） with a placement of over eight years was excavated from Shanghai Refuse Landfill, the largest landfill in China, and used for the construction of a two-stage bioreactor （AR biofilter） media for the biological treatment of 100 m3 of refuse landfill leachate. It was found that over 64% of COD, 96.9%-99.8% of NH4^＋-N, and 95.8%-99.8% of BOD5 could be removed by the AR biofilter, when the leachate with initial COD, BOD5, and NH4^＋-N concentrations were 986-4128 mg/L, 264--959 mg/L,m and 538-1583 mg/L, respectively. The corresponding concentrations in the effluent were reduced to below 30（000 mg/L, 2-12 mg/L, and 10-20 mg/L, respectively. The effluent was clear and pale yellow with suspended solid below 150 mg/L and color below 150 Pt/Co degree. Meanwhile, the total nitrogen removal was only 49%-63%, indicating a relative poor denitrification capacity of AR biofilter. The effluent pH was neutral and the population of Escherichia coli was less than 10^-1 CFU/mL. Hence, it was considered that the demonstration project can work well for the effective treatment of leachate.展开更多
Soil contamination by metals is a worldwide environmental problem. Electrokinetic extraction is a promising technology for in-situ remediation of contaminated soils of low hydraulic permeability. However, the extracti...Soil contamination by metals is a worldwide environmental problem. Electrokinetic extraction is a promising technology for in-situ remediation of contaminated soils of low hydraulic permeability. However, the extraction of metals is usually hindered by the high buffer capacity of natural soils. Organophosphonates are strong metal chelates as ethylenediaminetetraacetic acid(EDTA) which has been widely studied in the enhancement of electrokinetic remediation. In this study, batch desorption experiments and bench-scale electrokinetic extraction experiments were carried out to study the effect of two organophosphonates, i.e.,(nitrilotrimethylene)triphosphonate(NTMP) &(ethylenedinitrilo)-tetramethylenephosphonate(EDTMP), on the extraction of cadmium from a natural clay in comparison with EDTA. Results of the batch desorption experiments showed that more than 75% of the sorbed cadmium could be dissolved into solution using 0.1 mol·L^(-1) organophosphonates or EDTA in the wide p H range of 1–11. Results of the electrokinetic extraction experiments showed that the cadmium spiked in the specimen migrated towards the anode with the enhancement of NTMP,EDTMP, and EDTA under a constant voltage gradient of approximately 1.0 V·cm-1. Although cadmium mobilization enhanced by EDTA was more efficient than that by the organophosphonates, accumulation of cadmium was observed in the vicinity of the anode. The average removal efficiencies of cadmium from the soil after approximately 5 days of electrokinetic extraction enhanced by 0.1 mol·L-1 NTMP(22.8%) and EDTMP(22.4%) were higher than that by 0.1 mol·L^(-1) EDTA(15.1%).展开更多
The Hα line is an important optical line in solar observations containing the information from the photosphere to the chromosphere. To study the mechanisms of solar eruptions and the plasma dynamics in the lower atmo...The Hα line is an important optical line in solar observations containing the information from the photosphere to the chromosphere. To study the mechanisms of solar eruptions and the plasma dynamics in the lower atmosphere, the Chinese Hα Solar Explorer(CHASE) was launched into a Sun-synchronous orbit on October 14, 2021. The scientific payload of the CHASE satellite is the Hα Imaging Spectrograph(HIS). The CHASE/HIS acquires, for the first time, seeing-free Hα spectroscopic observations with high spectral and temporal resolutions. It consists of two observational modes. The raster scanning mode provides full-Sun or region-of-interest spectra at Hα(6559.7-6565.9 ?) and Fe I(6567.8-6570.6 ?) wavebands. The continuum imaging mode obtains full-Sun photospheric images at around 6689 ?. In this paper, we present detailed calibration procedures for the CHASE/HIS science data, including the dark-field and flat-field correction, slit image curvature correction, wavelength and intensity calibration, and coordinate transformation. The higher-level data products can be directly used for scientific research.展开更多
The influence of different illumination intensities on cyanobacterial calcification induced removal of heavy metals from contaminated mine water was studied. Cyanobacterial calcification experiments were performed usi...The influence of different illumination intensities on cyanobacterial calcification induced removal of heavy metals from contaminated mine water was studied. Cyanobacterial calcification experiments were performed using a growth medium intended to simulate contaminated mine water. The results indicate that calcification can promote the removal of heavy metal ions. As the illumination intensity became stronger calcification rates increased and the removal of Zn2+ and Cd2+ became more obvious. When the illumination intensity was 10000 lux the removal of Pb2+ was the largest observed: stronger or weaker illumination reduced the amount of lead removed. The removal of three different heavy metals complies with an index function. For identical illumination intensities different ions were removed to different degrees.展开更多
The pots discovered in Inner Mongolia and Hebei Province are huge with a maximum diameter of 9 m and a depth of 3.5 m, singular in shape,caused by weathering and wind erosion and have certain direction. They are a kin...The pots discovered in Inner Mongolia and Hebei Province are huge with a maximum diameter of 9 m and a depth of 3.5 m, singular in shape,caused by weathering and wind erosion and have certain direction. They are a kind of typical climatic geomorphology. This展开更多
CoCu/TiO_2 catalysts promoted using alkali metals（Li, Na, K, Rb, and Cs） were prepared by the homogeneous deposition-precipitation method followed by the incipient wetness impregnation method. The influences of the ...CoCu/TiO_2 catalysts promoted using alkali metals（Li, Na, K, Rb, and Cs） were prepared by the homogeneous deposition-precipitation method followed by the incipient wetness impregnation method. The influences of the alkali metals on the physicochemical properties of the CoCu/TiO_2 catalysts and the catalytic performance for CO_2 hydrogenation to long-chain hydrocarbons（C_（5＋））were investigated in this work. According to the characterization of the catalysts based on X-ray photoelectron spectroscopy, X-ray diffraction, CO_2 temperature-programmed desorption（TPD）, and H_2-TPD, the introduction of alkali metals could increase the CO_2 adsorption and decrease the H_2 chemisorption, which could suppress the formation of CH_4, enhance the production of C_（5＋）, and decrease the hydrogenation activity. Among all the promoters, the Na-modified CoCu/TiO_2 catalyst provided the maximum C_（5＋） yield of 5.4%, with a CO_2 conversion of 18.4% and C_（5＋） selectivity of42.1%, because it showed the strongest basicity and a slight decrease in the amount of H_2 desorption;it also exhibited excellent catalytic stability of more than 200 h.展开更多
The lateral response of combined pile-raft foundations(CPRFs)adjacent to tunnel excavation is a challenging problem owing to the complexity of the pile-raft connections.In current engineering practices,the impact of t...The lateral response of combined pile-raft foundations(CPRFs)adjacent to tunnel excavation is a challenging problem owing to the complexity of the pile-raft connections.In current engineering practices,the impact of these connections on the lateral performance of CPRFs is frequently overlooked,despite their importance.To address this issue,this study conducted three-dimensional finite element analyses to evaluate the contribution of pile-raft connections to the tunnelling-induced lateral performance of CPRFs in saturated clay.In the analysis,both passive and active loading at the pile head could be considered by varying the tunnel depth.Several parameter studies,such as relative pile-raft modulus,pile embedded modulus,pile embedded depths,and pile shaft skin friction,were conducted to determine the optimal design parameters for CPRFs.The results indicate that pile-raft connections significantly affect the tunnellinginduced deflections and bending moments of pile groups.Inspired by the results,a simplified design method,the pile-raft connection coefficient Kc was proposed.Additionally,the pile-head restraint percentage was established to make a relationship with the pile-raft connection coefficient in order to assess the pile-raft connection and guide the pile-raft design.In this paper,the recommended range value of Kc is 10–200 and the range value of pile-head restraint percentage is 24%–42%.展开更多
In this study,the interaction between TPE-Ph COF and ammonia molecules,as well as the mechanism of fluorescence detection of ammonia,were comprehensively investigated using density functional theory(DFT)and time-depen...In this study,the interaction between TPE-Ph COF and ammonia molecules,as well as the mechanism of fluorescence detection of ammonia,were comprehensively investigated using density functional theory(DFT)and time-dependent density functional theory(TD-DFT).It was found that the binding between TPE-Ph COF and ammonia molecules occurs primarily through coordination bonds or hydrogen bonds.Specifically,the formation of coordination bonds significantly changes the intramolecular charge transfer of TPE-Ph COF,leading to fluorescence quenching.Computational analysis revealed the changes in electron and hole distributions upon the binding of ammonia to TPE-Ph COF,as well as the competition between nonradiative and radiative transitions during the photophysical processes,thereby elucidating the intrinsic mechanism of fluorescence response.展开更多
In situ phase separation precipitates play an important role in enhancing the thermoelectric properties of copper sulfides by suppressing phonon transmission.In this study,Cu1.8S composites were fabricated by melting ...In situ phase separation precipitates play an important role in enhancing the thermoelectric properties of copper sulfides by suppressing phonon transmission.In this study,Cu1.8S composites were fabricated by melting reactions and spark plasma sintering.The complex structures,namely,micron-PbS,Sb_(2)S_(3),nano-FeS,and multiscale pores,originate from the introduction of FePb_(4)Sb_(6)S_(14)into the Cu1.8S matrix.Using effective element(Fe)doping and multiscale precipitates,the Cu_(1.8)S+0.5 wt%FePb_(4)Sb_(6)S_(14)bulk composite reached a high dimensionless figure of merit(ZT)value of 1.1 at 773 K.Furthermore,the modulus obtained for this sample was approximately 40.27 GPa,which was higher than that of the pristine sample.This study provides a novel strategy for realizing heterovalent doping while forming various precipitates via in situ phase separation by natural minerals,which has been proven to be effective in improving the thermoelectric and mechanical performance of copper sulfides and is worth promoting in other thermoelectric systems.展开更多
With the continuous advancement of China’s“peak carbon dioxide emissions and Carbon Neutrality”process,the proportion of wind power is increasing.In the current research,aiming at the problem that the forecasting m...With the continuous advancement of China’s“peak carbon dioxide emissions and Carbon Neutrality”process,the proportion of wind power is increasing.In the current research,aiming at the problem that the forecasting model is outdated due to the continuous updating of wind power data,a short-term wind power forecasting algorithm based on Incremental Learning-Bagging Deep Hybrid Kernel Extreme Learning Machine(IL-Bagging-DHKELM)error affinity propagation cluster analysis is proposed.The algorithm effectively combines deep hybrid kernel extreme learning machine(DHKELM)with incremental learning(IL).Firstly,an initial wind power prediction model is trained using the Bagging-DHKELM model.Secondly,Euclidean morphological distance affinity propagation AP clustering algorithm is used to cluster and analyze the prediction error of wind power obtained from the initial training model.Finally,the correlation between wind power prediction errors and Numerical Weather Prediction(NWP)data is introduced as incremental updates to the initial wind power prediction model.During the incremental learning process,multiple error performance indicators are used to measure the overall model performance,thereby enabling incremental updates of wind power models.Practical examples show the method proposed in this article reduces the root mean square error of the initial model by 1.9 percentage points,indicating that this method can be better adapted to the current scenario of the continuous increase in wind power penetration rate.The accuracy and precision of wind power generation prediction are effectively improved through the method.展开更多
Investigating the dynamic mechanical behavior of single-crystal aluminum oxynitride(AlON)is fascinating and crucial for understanding material performance in relevant applications.Nevertheless,few studies have explore...Investigating the dynamic mechanical behavior of single-crystal aluminum oxynitride(AlON)is fascinating and crucial for understanding material performance in relevant applications.Nevertheless,few studies have explored the dynamic mechanical properties of AlON single crystals.In this study,a series of nanoimpact experiments(representative strain rateε˙r≈102s^(-1))were performed on three principal orientations((010),(101),and(111))of grains to extract the dynamic mechanical responses of AlON single crystals.Our results reveal that the dynamic plasticity of an AlON single crystal is governed by a combination of mechanisms,including dislocation motion and amorphization.Significantly,the localized amorphization induced by mechanical deformation has a softening effect(a lower dynamic hardness).The crystallographic orientation affects the dynamic hardness similarly to the static hardness.In particular,the(111)orientation results in the highest hardness,whereas the(010)orientation is the softest among the three principal orientations.This dependency aligns with the expectations derived from applying Schmid law.Furthermore,both the dynamic and static hardnesses exhibit typical indentation size effects(ISEs),which can be effectively described via the strain gradient theory associated with the geometrically necessary dislocations.In addition,the size and rate dependencies of the dynamic hardness can be decoupled into two independent terms.展开更多
Anticancer platinum prodrugs that can be controllably activated are highly desired for personalized precision medicine and patient compliance in cancer therapy.However,the clinical application of platinum(Ⅳ)prodrugs(...Anticancer platinum prodrugs that can be controllably activated are highly desired for personalized precision medicine and patient compliance in cancer therapy.However,the clinical application of platinum(Ⅳ)prodrugs(Pt(Ⅳ))is restricted by tissue penetration of external irradiation.Here,we report a novel Pt(Ⅳ)activation strategy based on endogenous luminescence of tumor microenvironment responsiveness,which completely circumvents the limitation of external irradiation.The designed Pt(Ⅳ)–Lu,a mixture of trans,trans,trans-[Pt(N_(3))_(2)(OH)_(2)(py)_(2)]and luminol(Lu),has controllable activation property:it remains inert in reductant environment and normal tissues,but under tumor microenvironment,Lu will be oxidized to produce blue luminescence,which rapidly reduce Pt(Ⅳ)to Pt(Ⅱ)without the need of any external activator.Pt(Ⅳ)–Lu shows excellent responsive antitumor ability both in vitro and in vivo.Compared to cisplatin,the median lethal dose in BALB/c mice increased by an order of magnitude.Our results suggest that Pt(Ⅳ)–Lu exhibits highly controllable activation property,superior antitumor activity,and good biosafety,which may provide a novel strategy for the design of platinum prodrugs.展开更多
The fluvio-lacustrine sedimentary sequences in the Nihewan Basin, northern China, are important for studying Quaternary land mammal evolution and Paleolithic settlements in the high-latitude temperate East Asia. Here ...The fluvio-lacustrine sedimentary sequences in the Nihewan Basin, northern China, are important for studying Quaternary land mammal evolution and Paleolithic settlements in the high-latitude temperate East Asia. Here we report new magnetostrati- graphic results that constrain age of the Hougou Paleolithic site in this basin. Magnetite and hematite were identified as carriers of the characteristic remanent magnetizations, with the former being dominant. Magnetic polarity stratigraphy shows that the Hougou sequence recorded the very late Matuyama reverse chron and the Brunhes normal chron. The age of the Hougou Paleolithic site was estimated to be 395 ka based on an averaged rate of sediment accumulation. The combination of our mag- netostratigraphy and previously published chronological data for early Paleolithic or human sites in the high-latitude northern China may document a persistent colonization of the hostile high-latitude areas of the eastern Old World during the mid- die-early Pleistocene.展开更多
基金supported by China National Space Administration(CNSA)。
文摘The Chinese Hα Solar Explorer(CHASE), dubbed “Xihe”—Goddess of the Sun, was launched on October 14, 2021 as the first solar space mission of China National Space Administration(CNSA). The CHASE mission is designed to test a newly developed satellite platform and to acquire the spectroscopic observations in the Hα waveband. The Hα Imaging Spectrograph(HIS)is the scientific payload of the CHASE satellite. It consists of two observational modes: raster scanning mode and continuum imaging mode. The raster scanning mode obtains full-Sun or region-of-interest spectral images from 6559.7 to 6565.9 ? and from 6567.8 to 6570.6 ? with 0.024 ? pixel spectral resolution and 1 min temporal resolution. The continuum imaging mode obtains photospheric images in continuum around 6689 ? with the full width at half maximum of 13.4 ?. The CHASE mission will advance our understanding of the dynamics of solar activity in the photosphere and chromosphere. In this paper, we present an overview of the CHASE mission including the scientific objectives, HIS instrument overview, data calibration flow, and first results of on-orbit observations.
基金This work is supported by the Knowledge Innovation Program of the Chinese Academy of Sciences （KZCX2- YW-120）the National Commission on Stratigraphy of China+1 种基金the Ministry of Science and Technology of China （2006FY120300, 2006CB806400）the National Natural Science Foundation of China （40232023）.
文摘The Tunggurian Age was nominated in 1984, and the Second National Commission on Stratigraphy of China formally suggested establishing the corresponding chronostratigraphic unit, the Tunggurian Stage, based on the Tunggurian Age in 1999. The name of this stage comes from a lithostratigraphic unit, the Tunggur Formation, and the stratotype section is located at the Tunggur tableland, 15 km southeast of Saihan Gobi Township, Sonid Left Banner, Inner Mongolia. The Tunggurian Age is correlated to the Astaracian of the European land mammal ages, and they share the same definition of the lower boundary at the base of the paleomagnetic Chron C5Bn.1r with an age of 15.0 Ma. In the Tairum Nor section on the southeastern edge of the Tunggur tableland, this boundary is situated within the successive deposits of reddish-brown massive mudstone of the lower part of the Tunggur Formation, with a distance of 7.6 m from the base of the grayish-white sandstones in the middle part of the section. The Tunggurian is approximately correlated to the upper part of the marine Langhian and the marine Serravallian in the International Stratigraphical Chart. The Tunggurian Stage includes two Neogene mammal faunal units, i.e. NMU 6 （MN 6） and NMU 7 （MN 7/8）. The Tairnm Nor fauna from the Talrnm Nor section corresponds to NMU 6, and the Tunggur fauna （senso stricto） from the localities on the northwestern edge of the Tunggur tableland, such as Platybelodon Quarry, Wolf Camp and Moergen, corresponds to NMU 7. Among the Middle Miocene mammalian faunas in China, the Laogou fauna from the Linxia Basin, Gansu, the Quantougou fauna from the Lanzhou Basin, Gansu, the Halamagai fauna from the northern Junggar Basin, Xinjiang, and the Dingjiaergou fauna from Tongxin, Ningxia correspond to NMU 6.
基金supported by the Ministry of Education of China (No. 305005)the Science and Technology Commission of Shanghai Municipality (No. 05DZ12003).
文摘A field-scale aged refuse （AR） biofilter constructed in Shanghai Refuse Landfill, containing about 7000 m^3 aged refuse inside, was evaluated for its performance in the treatment of landfill leachate. This AR biofilter can be divided into three stages and can manage 50 m^3 landfill leachate per day. The physical, chemical, and biological characteristics of AR were analyzed for evaluating the AR biofilter as leachate treatment host. The results revealed that over 87.8%-96.2% of COD and 96.9%-99.4% of ammonia nitrogen were removed by the three-stage AR biofilter when the infiuent leachate COD and ammonia nitrogen concentration were in the range 5478-10842 mg/L and 811-1582 mg/L, respectively. The final effluent was inodorous and pale yellow with COD and ammonia nitrogen below 267-1020 mg/L and 6-45 mg/L, respectively. The three-stage AR biofilter had efficient nitrification but relative poor denitrification capacity with a total nitrogen （TN） removal of 58%-73%. The external temperature of AR biofilter did not influence the total ammonia nitrogen removal significantly. It was concluded that the scale-up AR biofilter can work very well and can be a promising technology for the treatment of landfill leachate.
基金the National Natural Science Foundation of China (40671153)the Scientific Research Fund of Hunan Provincial Education Department (05C175) the Knowledge Innovation Program of Chinese Academy Sciences (KZCX2- YW-302)
文摘This paper discussed theory and methodologies of debris-flow risk assessment and established an implementation process according to indicators of debris-flow hazard degree, vulnerability, risk degree, etc. Among these methodologies, historical and potential hazard degree was comprehensively considered into hazard assessment and hazard index was presented to indicate the debris-flow hazard degree. Regarding debris-flow vulnerability assessment, its statistical data and calculating procedure were based on the hazard-degree regionalization instead of administrative divisions, which improved the assessing scientificity and precision. These quantitative methodologies integrated with Geography Information System （GIS） were applied to the risk assessment of debris flows in the upper reach of Yangtze River. Its results were in substantial agreement on investigation data and the actual distribution of debris flows, which showed that these principles and methodologies were reasonable and feasible and can provide basis or reference for debris-flow risk assessment and disaster management.
文摘Approximately 7000 m^3 of aged refuse （AR） with a placement of over eight years was excavated from Shanghai Refuse Landfill, the largest landfill in China, and used for the construction of a two-stage bioreactor （AR biofilter） media for the biological treatment of 100 m3 of refuse landfill leachate. It was found that over 64% of COD, 96.9%-99.8% of NH4^＋-N, and 95.8%-99.8% of BOD5 could be removed by the AR biofilter, when the leachate with initial COD, BOD5, and NH4^＋-N concentrations were 986-4128 mg/L, 264--959 mg/L,m and 538-1583 mg/L, respectively. The corresponding concentrations in the effluent were reduced to below 30（000 mg/L, 2-12 mg/L, and 10-20 mg/L, respectively. The effluent was clear and pale yellow with suspended solid below 150 mg/L and color below 150 Pt/Co degree. Meanwhile, the total nitrogen removal was only 49%-63%, indicating a relative poor denitrification capacity of AR biofilter. The effluent pH was neutral and the population of Escherichia coli was less than 10^-1 CFU/mL. Hence, it was considered that the demonstration project can work well for the effective treatment of leachate.
基金Supported by the National Natural Science Foundation of China(41201303)Shandong Province Natural Science Foundation,China(ZR2017QEE016)+1 种基金the Fundamental Research for the Central Universities(14CX02191A,17CX02075)State Key Laboratory of Pollution Control and Resource Reuse Foundation(PCRRF13023)
文摘Soil contamination by metals is a worldwide environmental problem. Electrokinetic extraction is a promising technology for in-situ remediation of contaminated soils of low hydraulic permeability. However, the extraction of metals is usually hindered by the high buffer capacity of natural soils. Organophosphonates are strong metal chelates as ethylenediaminetetraacetic acid(EDTA) which has been widely studied in the enhancement of electrokinetic remediation. In this study, batch desorption experiments and bench-scale electrokinetic extraction experiments were carried out to study the effect of two organophosphonates, i.e.,(nitrilotrimethylene)triphosphonate(NTMP) &(ethylenedinitrilo)-tetramethylenephosphonate(EDTMP), on the extraction of cadmium from a natural clay in comparison with EDTA. Results of the batch desorption experiments showed that more than 75% of the sorbed cadmium could be dissolved into solution using 0.1 mol·L^(-1) organophosphonates or EDTA in the wide p H range of 1–11. Results of the electrokinetic extraction experiments showed that the cadmium spiked in the specimen migrated towards the anode with the enhancement of NTMP,EDTMP, and EDTA under a constant voltage gradient of approximately 1.0 V·cm-1. Although cadmium mobilization enhanced by EDTA was more efficient than that by the organophosphonates, accumulation of cadmium was observed in the vicinity of the anode. The average removal efficiencies of cadmium from the soil after approximately 5 days of electrokinetic extraction enhanced by 0.1 mol·L-1 NTMP(22.8%) and EDTMP(22.4%) were higher than that by 0.1 mol·L^(-1) EDTA(15.1%).
基金supported by China National Space Administration。
文摘The Hα line is an important optical line in solar observations containing the information from the photosphere to the chromosphere. To study the mechanisms of solar eruptions and the plasma dynamics in the lower atmosphere, the Chinese Hα Solar Explorer(CHASE) was launched into a Sun-synchronous orbit on October 14, 2021. The scientific payload of the CHASE satellite is the Hα Imaging Spectrograph(HIS). The CHASE/HIS acquires, for the first time, seeing-free Hα spectroscopic observations with high spectral and temporal resolutions. It consists of two observational modes. The raster scanning mode provides full-Sun or region-of-interest spectra at Hα(6559.7-6565.9 ?) and Fe I(6567.8-6570.6 ?) wavebands. The continuum imaging mode obtains full-Sun photospheric images at around 6689 ?. In this paper, we present detailed calibration procedures for the CHASE/HIS science data, including the dark-field and flat-field correction, slit image curvature correction, wavelength and intensity calibration, and coordinate transformation. The higher-level data products can be directly used for scientific research.
基金supported by the National Basic Research Program of China (No.2007CB209401)Research on basic theory about the mechanism of water inrush and its prevention in coal mines and supported by the Fundamental Research Funds for the Central Universities
文摘The influence of different illumination intensities on cyanobacterial calcification induced removal of heavy metals from contaminated mine water was studied. Cyanobacterial calcification experiments were performed using a growth medium intended to simulate contaminated mine water. The results indicate that calcification can promote the removal of heavy metal ions. As the illumination intensity became stronger calcification rates increased and the removal of Zn2+ and Cd2+ became more obvious. When the illumination intensity was 10000 lux the removal of Pb2+ was the largest observed: stronger or weaker illumination reduced the amount of lead removed. The removal of three different heavy metals complies with an index function. For identical illumination intensities different ions were removed to different degrees.
文摘The pots discovered in Inner Mongolia and Hebei Province are huge with a maximum diameter of 9 m and a depth of 3.5 m, singular in shape,caused by weathering and wind erosion and have certain direction. They are a kind of typical climatic geomorphology. This
文摘CoCu/TiO_2 catalysts promoted using alkali metals（Li, Na, K, Rb, and Cs） were prepared by the homogeneous deposition-precipitation method followed by the incipient wetness impregnation method. The influences of the alkali metals on the physicochemical properties of the CoCu/TiO_2 catalysts and the catalytic performance for CO_2 hydrogenation to long-chain hydrocarbons（C_（5＋））were investigated in this work. According to the characterization of the catalysts based on X-ray photoelectron spectroscopy, X-ray diffraction, CO_2 temperature-programmed desorption（TPD）, and H_2-TPD, the introduction of alkali metals could increase the CO_2 adsorption and decrease the H_2 chemisorption, which could suppress the formation of CH_4, enhance the production of C_（5＋）, and decrease the hydrogenation activity. Among all the promoters, the Na-modified CoCu/TiO_2 catalyst provided the maximum C_（5＋） yield of 5.4%, with a CO_2 conversion of 18.4% and C_（5＋） selectivity of42.1%, because it showed the strongest basicity and a slight decrease in the amount of H_2 desorption;it also exhibited excellent catalytic stability of more than 200 h.
基金funded by the National Natural Science Foundation of China(Grant No.51878157,52308341)the Natural Science Foundation of Jiangsu Province(Grant No.BK20181282)the China Scholarship Council(CSC202106090083).
文摘The lateral response of combined pile-raft foundations(CPRFs)adjacent to tunnel excavation is a challenging problem owing to the complexity of the pile-raft connections.In current engineering practices,the impact of these connections on the lateral performance of CPRFs is frequently overlooked,despite their importance.To address this issue,this study conducted three-dimensional finite element analyses to evaluate the contribution of pile-raft connections to the tunnelling-induced lateral performance of CPRFs in saturated clay.In the analysis,both passive and active loading at the pile head could be considered by varying the tunnel depth.Several parameter studies,such as relative pile-raft modulus,pile embedded modulus,pile embedded depths,and pile shaft skin friction,were conducted to determine the optimal design parameters for CPRFs.The results indicate that pile-raft connections significantly affect the tunnellinginduced deflections and bending moments of pile groups.Inspired by the results,a simplified design method,the pile-raft connection coefficient Kc was proposed.Additionally,the pile-head restraint percentage was established to make a relationship with the pile-raft connection coefficient in order to assess the pile-raft connection and guide the pile-raft design.In this paper,the recommended range value of Kc is 10–200 and the range value of pile-head restraint percentage is 24%–42%.
文摘In this study,the interaction between TPE-Ph COF and ammonia molecules,as well as the mechanism of fluorescence detection of ammonia,were comprehensively investigated using density functional theory(DFT)and time-dependent density functional theory(TD-DFT).It was found that the binding between TPE-Ph COF and ammonia molecules occurs primarily through coordination bonds or hydrogen bonds.Specifically,the formation of coordination bonds significantly changes the intramolecular charge transfer of TPE-Ph COF,leading to fluorescence quenching.Computational analysis revealed the changes in electron and hole distributions upon the binding of ammonia to TPE-Ph COF,as well as the competition between nonradiative and radiative transitions during the photophysical processes,thereby elucidating the intrinsic mechanism of fluorescence response.
基金the National Key R&D Program of China(No.2022YFF0503804)the National Natural Science Foundation of China(No.52162029),the Yunnan Provincial Natural Science Key Fund(No.202101AS070015)+1 种基金the Basic Research Project of Yunnan Science and Technology Program(No.202401AT070403)the Outstanding Youth Fund of Yunnan Province(No.202201AV070005).
文摘In situ phase separation precipitates play an important role in enhancing the thermoelectric properties of copper sulfides by suppressing phonon transmission.In this study,Cu1.8S composites were fabricated by melting reactions and spark plasma sintering.The complex structures,namely,micron-PbS,Sb_(2)S_(3),nano-FeS,and multiscale pores,originate from the introduction of FePb_(4)Sb_(6)S_(14)into the Cu1.8S matrix.Using effective element(Fe)doping and multiscale precipitates,the Cu_(1.8)S+0.5 wt%FePb_(4)Sb_(6)S_(14)bulk composite reached a high dimensionless figure of merit(ZT)value of 1.1 at 773 K.Furthermore,the modulus obtained for this sample was approximately 40.27 GPa,which was higher than that of the pristine sample.This study provides a novel strategy for realizing heterovalent doping while forming various precipitates via in situ phase separation by natural minerals,which has been proven to be effective in improving the thermoelectric and mechanical performance of copper sulfides and is worth promoting in other thermoelectric systems.
基金funded by Liaoning Provincial Department of Science and Technology(2023JH2/101600058)。
文摘With the continuous advancement of China’s“peak carbon dioxide emissions and Carbon Neutrality”process,the proportion of wind power is increasing.In the current research,aiming at the problem that the forecasting model is outdated due to the continuous updating of wind power data,a short-term wind power forecasting algorithm based on Incremental Learning-Bagging Deep Hybrid Kernel Extreme Learning Machine(IL-Bagging-DHKELM)error affinity propagation cluster analysis is proposed.The algorithm effectively combines deep hybrid kernel extreme learning machine(DHKELM)with incremental learning(IL).Firstly,an initial wind power prediction model is trained using the Bagging-DHKELM model.Secondly,Euclidean morphological distance affinity propagation AP clustering algorithm is used to cluster and analyze the prediction error of wind power obtained from the initial training model.Finally,the correlation between wind power prediction errors and Numerical Weather Prediction(NWP)data is introduced as incremental updates to the initial wind power prediction model.During the incremental learning process,multiple error performance indicators are used to measure the overall model performance,thereby enabling incremental updates of wind power models.Practical examples show the method proposed in this article reduces the root mean square error of the initial model by 1.9 percentage points,indicating that this method can be better adapted to the current scenario of the continuous increase in wind power penetration rate.The accuracy and precision of wind power generation prediction are effectively improved through the method.
基金supported by the Defense Industrial Technology Development Program(No.JCKYS2023212805)the National Natural Science Foundation of China(No.12205027)the Sichuan Science and Technology Program(Nos.2022NSFSC1240 and 2023ZYD0137).
文摘Investigating the dynamic mechanical behavior of single-crystal aluminum oxynitride(AlON)is fascinating and crucial for understanding material performance in relevant applications.Nevertheless,few studies have explored the dynamic mechanical properties of AlON single crystals.In this study,a series of nanoimpact experiments(representative strain rateε˙r≈102s^(-1))were performed on three principal orientations((010),(101),and(111))of grains to extract the dynamic mechanical responses of AlON single crystals.Our results reveal that the dynamic plasticity of an AlON single crystal is governed by a combination of mechanisms,including dislocation motion and amorphization.Significantly,the localized amorphization induced by mechanical deformation has a softening effect(a lower dynamic hardness).The crystallographic orientation affects the dynamic hardness similarly to the static hardness.In particular,the(111)orientation results in the highest hardness,whereas the(010)orientation is the softest among the three principal orientations.This dependency aligns with the expectations derived from applying Schmid law.Furthermore,both the dynamic and static hardnesses exhibit typical indentation size effects(ISEs),which can be effectively described via the strain gradient theory associated with the geometrically necessary dislocations.In addition,the size and rate dependencies of the dynamic hardness can be decoupled into two independent terms.
基金supported by the National Natural Science Foundation of China(Nos.32201171 and 82372115)the Science and Technology Program of Guangzhou(No.202102021266)。
文摘Anticancer platinum prodrugs that can be controllably activated are highly desired for personalized precision medicine and patient compliance in cancer therapy.However,the clinical application of platinum(Ⅳ)prodrugs(Pt(Ⅳ))is restricted by tissue penetration of external irradiation.Here,we report a novel Pt(Ⅳ)activation strategy based on endogenous luminescence of tumor microenvironment responsiveness,which completely circumvents the limitation of external irradiation.The designed Pt(Ⅳ)–Lu,a mixture of trans,trans,trans-[Pt(N_(3))_(2)(OH)_(2)(py)_(2)]and luminol(Lu),has controllable activation property:it remains inert in reductant environment and normal tissues,but under tumor microenvironment,Lu will be oxidized to produce blue luminescence,which rapidly reduce Pt(Ⅳ)to Pt(Ⅱ)without the need of any external activator.Pt(Ⅳ)–Lu shows excellent responsive antitumor ability both in vitro and in vivo.Compared to cisplatin,the median lethal dose in BALB/c mice increased by an order of magnitude.Our results suggest that Pt(Ⅳ)–Lu exhibits highly controllable activation property,superior antitumor activity,and good biosafety,which may provide a novel strategy for the design of platinum prodrugs.
基金supported by the National Natural Science Foundation of China (Grant Nos. 40925012 and 40821091)the Ministry of Science and Technology of China (Grant No. 2007FY110200)the Chinese Academy of Sciences (Grant No. KZCX2-EW-117)
文摘The fluvio-lacustrine sedimentary sequences in the Nihewan Basin, northern China, are important for studying Quaternary land mammal evolution and Paleolithic settlements in the high-latitude temperate East Asia. Here we report new magnetostrati- graphic results that constrain age of the Hougou Paleolithic site in this basin. Magnetite and hematite were identified as carriers of the characteristic remanent magnetizations, with the former being dominant. Magnetic polarity stratigraphy shows that the Hougou sequence recorded the very late Matuyama reverse chron and the Brunhes normal chron. The age of the Hougou Paleolithic site was estimated to be 395 ka based on an averaged rate of sediment accumulation. The combination of our mag- netostratigraphy and previously published chronological data for early Paleolithic or human sites in the high-latitude northern China may document a persistent colonization of the hostile high-latitude areas of the eastern Old World during the mid- die-early Pleistocene.
