The purpose of this study was to investigate the pollution level of trace metals As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Se and Zn in agricultural soil around the water reservoir. A total of 36 soil samples were colle...The purpose of this study was to investigate the pollution level of trace metals As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Se and Zn in agricultural soil around the water reservoir. A total of 36 soil samples were collected both during off-season agriculture and pluvial agriculture from April to October 2022. The samples were analyzed for trace metals according to the standard methods of the US EPA 2007 with a microwave plasma atomic emission spectrometer (MP-AES), Agilent Model 4210. The pollution level was assessed using contamination factor (Cf) and modified contamination degree (mCd). During the off-season, the concentration of trace metals followed in descending order as Mn > Cr > Cu > Pb > Zn. As, Cd, Co, Hg, Ni, Sb and Se were below the detectable limits. In pluvial season, the concentration of traces of metal follows the order Mn > Cr > Zn > Cu > Ni > Pb > Hg > As. Cd, Co, Sb and Se remain below the detectable limits. The concentrations of Cr, Mn and Zn were lower in the off-season agriculture than in pluvial agriculture. For Cu and Pb, the concentrations were higher in the off-season than in pluvial agriculture. The Cf ranges from 0.24 to 11.70 depending on the considered trace metal. The Cf values of As, Ni, Pb, Zn and Mn indicated that the agricultural study soil was lowery contaminated by these trace metals. The agricultural study soil was moderately contaminated by Cr and Cu, and highly contaminated by Hg. Globally the agricultural study soil presents a moderate degree of contamination (mCd 2.25) by the eight trace metals studied. This result provides information on understanding the risks of trace metal contamination of agricultural soil. It is important to anticipate the control of soil contamination through regular monitoring of toxic metals in agricultural soils, control the quality of chemicals used in agriculture and regulate their use.展开更多
In this paper,we find some mistakes in the paper “Several Inequalities of Matrix Traces” which was published in Chinese Quarterly Journal of Mathematics,Vol.10,No.2.
Currently, the selection of receiving traces in geometry design is mostly based on the horizontal layered medium hypothesis, which is unable to meet survey requirements in a complex area. This paper estimates the opti...Currently, the selection of receiving traces in geometry design is mostly based on the horizontal layered medium hypothesis, which is unable to meet survey requirements in a complex area. This paper estimates the optimal number of receiving traces in field geometry using a numerical simulation based on a field test conducted in previous research （Zhu et al., 2011）. A mathematical model is established for total energy and average efficiency energy using fixed trace spacing and optimal receiving traces are estimated. Seismic data acquired in a complex work area are used to verify the correctness of the proposed method. Results of model data calculations and actual data processing show that results are in agreement. This indicates that the proposed method is reasonable, correct, sufficiently scientific, and can be regarded as a novel method for use in seismic geometry design in complex geological regions.展开更多
This study was conducted during Dec2011-Nov2012 on three stations located in the south sector of Main Outfall Drain (MOD) River. Station 1 was near Al-Holandee Bridge which was the general carriage way in the center o...This study was conducted during Dec2011-Nov2012 on three stations located in the south sector of Main Outfall Drain (MOD) River. Station 1 was near Al-Holandee Bridge which was the general carriage way in the center of Al-Nassiriya city, station 2 was 20 km far from the first station, while station 3 was in the beginning of the new branch. This study reveals the Seasonal Variation of Total petroleum hydrocarbons (TPHs) in both surface waters, sediment and it is related with trace metals nickel and vanadium in water (dissolved, particulate) and sediment (residual and exchangeable) phases. Also, the study shows the relationships between the concentration of Ni and V with Total Organic Carbon (TOC%) in the sediment.展开更多
In this paper, the authors studied the traces of destruction in the fortress walls and houses of the Bosporan city of Kytaia. The study of this city has been ongoing since 1970. Over the past time, numerous damages ha...In this paper, the authors studied the traces of destruction in the fortress walls and houses of the Bosporan city of Kytaia. The study of this city has been ongoing since 1970. Over the past time, numerous damages have been identified at different sites of the ancient settlement. In the article, an attempt is made to compare some of them with the results of earthquakes on the Bosporus, about which the data of ancient authors were preserved.展开更多
Emerging contaminants constitute a set of substances that are released into the environment for which regulations are currently not established for their environmental monitoring, being antimony one of them. A new met...Emerging contaminants constitute a set of substances that are released into the environment for which regulations are currently not established for their environmental monitoring, being antimony one of them. A new methodology for Sb(III) traces monitoring by solid surface fluorescence is proposed. The metal was complexed with alizarine (Az) as fluorosphore reagent in alcaline medium in presence of the bile salt sodium cholate. To isolate the analyte of matrix constituents, a preconcentration/separation strategy on filter paper was introduced prior to determination step. The solid surface fluorescence was measured λem = 450 nm and λexc = 363 nm using a solid sampler holder. Under optimal conditions, the limits of detection and quantification of proposed methodology were 0.08 and 0.24 μg·L-1, respectively, showing a linear range from 0.24 to 304.4 μg·L-1 with good sensitivity and adequate selectivity. It was applied to the Sb(III) traces determination present in drinking water and beverages samples packaged in polyethylene terephthalate (PET) bottles widely consumed in Argentina. The combination of a preconcentration step on common filter paper and the inherent sensitivity of photoluminescent methods have permitted to achieve sensitivity similar to atomic spectroscopies using a lower price instrument typical in control laboratories. Precision and accuracy were tested with excellent agreement. Results were truenessed by ETAAS with satisfactory concordance.展开更多
The disposal of urban or hospital waste in open landfills is the easiest way to throw back of them without environmental concerns. MTEs （Metal Trace Elements） are the most toxic mineral elemems. This study evaluates...The disposal of urban or hospital waste in open landfills is the easiest way to throw back of them without environmental concerns. MTEs （Metal Trace Elements） are the most toxic mineral elemems. This study evaluates the impact of MTE on a neighboring human population or playing near a municipal dump. Two panels were composed of adult men and children （males under sixteen years old）. Four trace metal elements were analyzed： copper, lead, cadmium and zinc. The site of the study was the municipal waste dump in Marrakech （Morocco）. The results reveal abnormal concentrations of these MTEs in blood and hair of adults and children.展开更多
Surfactant enhanced chemofiltration on Nylon membranes pre-treated with hexadecyltrimethylammonium bromide (HTAB) and eosin dye (eo) is proposed for zinc traces quantification by solid surphase spectro- fluorimetry (S...Surfactant enhanced chemofiltration on Nylon membranes pre-treated with hexadecyltrimethylammonium bromide (HTAB) and eosin dye (eo) is proposed for zinc traces quantification by solid surphase spectro- fluorimetry (SSF, λexc = 532 nm;λem = 548 nm). Operational variables which have influence on quantitative retention of metal complex have been studied and optimized. At optimal experimental conditions, quantita- tive recovery was reached with a detection limit of 0.662 pg?L–1 and quantification limit of 2.20 pg?L–1. The calibration sensitivity was of 1.22 L?pg–1 for the new methodology with a linear range of 2.20 pg?L–1 to 779 pg?L–1 Zn (II). The tolerance levels of potential interfering ions were studied with good results. Recuperation studies were carried out by standard addition method applied to natural water samples (San Juan, Argentine) without previous treatment. The reproducibility (between-days precision) was also evaluated over 3 days by performing five determinations each day. CV% was 0.37. The performing obtained in sensitivity and selec- tivity thanks to chemofiltration step, converts the proposed methodology in an adequate alternative to con- ventional techniques for Zn (II) traces determination.展开更多
IEA-R1 nuclear reactor operation has the routine to control uranium content in pool water to be in trace range below 50 μg/L. There are several routes to determine the uranium trace content in water in the lite...IEA-R1 nuclear reactor operation has the routine to control uranium content in pool water to be in trace range below 50 μg/L. There are several routes to determine the uranium trace content in water in the literature;voltammetry has been systematically employed. In the present study, the chosen chemical determination of uranium traces used the voltammetric method known as AdCSV (adsorptive cathodic stripping voltammetry). This technique, based on mercury voltammetry, is an adequate methodology to determine uranium traces. The chloranilic acid [CAA] (2,5-dichloro-3,6-dihydroxy-1,4-benzo-quinone) is indicated as chelating agent. The redox reaction of UO2+2?with CAA is sensitive in the range of 2 2(CAA)2] reduction potential. In this work, we present the uranium trace results for IEA-R1 reactor water, sampled after an operation routine shutdown. The uranium trace determination for IEA-R1 pool water showed content around 1 μg/L [U] with statistical significance. Therefore the IEA-R1-reactor-water purification showed to be adequate and safe.展开更多
The aim of this work has been to evaluate the aluminium (Al(III)) traces contents in 24-hour urine samples from subjects with different tobacco smoke expositions using a new methodology with 1,4-dihydroxy-9, 10-anthra...The aim of this work has been to evaluate the aluminium (Al(III)) traces contents in 24-hour urine samples from subjects with different tobacco smoke expositions using a new methodology with 1,4-dihydroxy-9, 10-anthraquinone (Quinizarine, QZ) as a fluorosphore. Biological samples were tested using commercial reagent strips and clinical parameters. Al(III) was determined complexing with QZ followed by a solid phase extraction step using Nylon membranes as a solid support. The analyte was subsequently quantified by solid surface fluorescence (SSF, λem= 573, λexc= 490) with a detection limit of 0.88 μg L-1 and quantification limit of 2.69 μg L-1. The calibration curve was linear from 2.69 to 499.13 μg L-1 Al(III) (R2 = 0.9973). Urine samples were successfully analysed with an average recovery close to 100%. Solid phase extraction step showed efficacy to eliminate foreign ions and the highly fluorescent matrix own of urine. Results were validated by electrothermal atomic absorption spectrometry (ETAAS) with an adequate concordance. The new methodology has low operation cost with simple instrumentation and without organic solvent.展开更多
A new fluorescence silver nanosensor assisted by surfactant has been synthesized and applied to ultra trace nickel determination. Operational variables which influence nanomaterial synthesis have been studied and opti...A new fluorescence silver nanosensor assisted by surfactant has been synthesized and applied to ultra trace nickel determination. Operational variables which influence nanomaterial synthesis have been studied and optimized. Synthesis was very fast and simple using non polluting solvents; silver chemical reduction was carried out at room temperature. Spectroscopic studies were carried out in order to assure the uniformed of nanomaterial obtained. Fluorescent signal of silver nanoparticles resulted enhanced in presence of Ni（II）. At optimal experimental conditions, a detection limit of 0.036 pg＇L1 and quantification limit 0.12 pg＇L~ were obtained. The calibration sensitivity was 2 x 1014 L.pg-l.cm1 for the new methodology, with a range of linearity of six orders of magnitude between 0.12 and 2.93 × 10^5 pg L^-1. The tolerance levels for potential interferent ions were studied with good results. The proposed methodology represents a promising approach for Ni（II） traces quantification due to its low operation cost, simplicity of instrumentation, high sampling speed and non-polluting solvents.展开更多
For TA15 titanium alloy, slip is the dominant plastic deformation mechanism because of relatively high Al content. In order to reveal the grain-scale stress field and geometrically necessary dislocation（GND） density...For TA15 titanium alloy, slip is the dominant plastic deformation mechanism because of relatively high Al content. In order to reveal the grain-scale stress field and geometrically necessary dislocation（GND） density distribution around the slip traces and phase boundaries where the slip lines are blocked due to Burgers orientation relationship（OR） missing. We experimentally investigated tensile deformation on TA15 titanium alloy up to 2.0% strain at room temperature. The slip traces were observed and identified using high resolution scanning electron microscopy（SEM） and electron backscatter diffraction（EBSD） measurements. The grain-scale stress fields around the slip traces and phase boundaries were calculated by the cross-correlationbased method. Based on strain gradient theories, the density of GND was calculated and analyzed. The results indicate that the grain-scale stress is significantly concentrated at phase/grain boundaries and slip traces. Although there is an obvious GND accumulation in the vicinity of phase and subgrain boundaries, no GND density accumulation appears near the slip traces.展开更多
On the basis of topological criteria, metazoan traces can be classified as four ichnoorders (clusters) and twenty two ichnofamilies (kinds), which consist of nine basic and three combined topological configurations. ...On the basis of topological criteria, metazoan traces can be classified as four ichnoorders (clusters) and twenty two ichnofamilies (kinds), which consist of nine basic and three combined topological configurations. At a topological level, the behavioral diversity and complexity indicated by metazoan traces have remained quite stable since the Early Cambrian. Dramatic changes of these traits took place in the Neoproterozoic, in which 75% (12/16) of the topoichnotaxa and all nine basic topological configurations of metazoan traces occurred, but the most complex and highest level topological configuration occurred in the Early Cambrian of the coelomate animal explosive evolution, showing that in the Neoproterozoic and Early Cambrian gestated not only the Ediacarian fauna and all the basic types of multi cellular animals known today, but also all the basic and the most complex metazoan traces through geological time.展开更多
The application of reinforcement learning is widely used by multi-agent systems in recent years. An agent uses a multi-agent system to cooperate with other agents to accomplish the given task, and one agent′s behavio...The application of reinforcement learning is widely used by multi-agent systems in recent years. An agent uses a multi-agent system to cooperate with other agents to accomplish the given task, and one agent′s behavior usually affects the others′ behaviors. In traditional reinforcement learning, one agent takes the others location, so it is difficult to consider the others′ behavior, which decreases the learning efficiency. This paper proposes multi-agent reinforcement learning with cooperation based on eligibility traces, i.e. one agent estimates the other agent′s behavior with the other agent′s eligibility traces. The results of this simulation prove the validity of the proposed learning method.展开更多
In this paper we derive some inequalities for traces and singular values of the quaternion matrices,extend and improve some of the corresponding results appeared in other papers we know.
The task to estimate all the parameters of an unknown quantum state, also called quantum state tomography, is essential for characterizing and controlling quantum systems. In this paper, we utilize observable time tra...The task to estimate all the parameters of an unknown quantum state, also called quantum state tomography, is essential for characterizing and controlling quantum systems. In this paper, we utilize observable time traces to identify the initial quantum state of a closed quantum system, based on the state space approach in the control theory. In the informationally complete scenario, we show that with a linear regression estimation (LRE), the mean squared error (MSE) scales as , where N is the resource number. In the informationally incomplete scenario, we introduce regularization LRE to perform the state tomography task. We employ PBH test to demonstrate that closed quantum systems with only one observable are informationally incomplete and propose using observables, where d is the dimension of the quantum state, for informational completeness. Numerical examples demonstrate the effectiveness of our method.展开更多
In this paper,we study the traces and the extensions for weighted Sobolev spaces on upper half spaces when the weights reach to the borderline cases.We first give a full characterization of the existence of trace spac...In this paper,we study the traces and the extensions for weighted Sobolev spaces on upper half spaces when the weights reach to the borderline cases.We first give a full characterization of the existence of trace spaces for these weighted Sobolev spaces,and then study the trace parts and the extension parts between the weighted Sobolev spaces and a new kind of Besov-type spaces(on hyperplanes)which are defined by using integral averages over selected layers of dyadic cubes.展开更多
In this study,precise control over the thickness and termination of Ti3C2TX MXene flakes is achieved to enhance their electrical properties,environmental stability,and gas-sensing performance.Utilizing a hybrid method...In this study,precise control over the thickness and termination of Ti3C2TX MXene flakes is achieved to enhance their electrical properties,environmental stability,and gas-sensing performance.Utilizing a hybrid method involving high-pressure processing,stirring,and immiscible solutions,sub-100 nm MXene flake thickness is achieved within the MXene film on the Si-wafer.Functionalization control is achieved by defunctionalizing MXene at 650℃ under vacuum and H2 gas in a CVD furnace,followed by refunctionalization with iodine and bromine vaporization from a bubbler attached to the CVD.Notably,the introduction of iodine,which has a larger atomic size,lower electronegativity,reduce shielding effect,and lower hydrophilicity(contact angle:99°),profoundly affecting MXene.It improves the surface area(36.2 cm^(2) g^(-1)),oxidation stability in aqueous/ambient environments(21 days/80 days),and film conductivity(749 S m^(-1)).Additionally,it significantly enhances the gas-sensing performance,including the sensitivity(0.1119Ωppm^(-1)),response(0.2% and 23%to 50 ppb and 200 ppm NO_(2)),and response/recovery times(90/100 s).The reduced shielding effect of the–I-terminals and the metallic characteristics of MXene enhance the selectivity of I-MXene toward NO2.This approach paves the way for the development of stable and high-performance gas-sensing two-dimensional materials with promising prospects for future studies.展开更多
The Nuri deposit is the only Cu-W-Mo polymetallic deposit with large-scale WO3 resources in the eastern section of the Gangdese metallogenic belt,Tibet,China.However,the genetic type of this deposit has been controver...The Nuri deposit is the only Cu-W-Mo polymetallic deposit with large-scale WO3 resources in the eastern section of the Gangdese metallogenic belt,Tibet,China.However,the genetic type of this deposit has been controversial since its discovery.Based on a study of the geological characteristics of the deposit,this study presents mineralization stages,focusing on the oxide stage and the quartz-sulfide stage where scheelite is mainly formed,referred to as Sch-A and Sch-B,respectively.Through LA-ICP-MS trace element and Sr isotope analyses,the origin,evolutionary process of the oreforming fluid and genesis of the ore deposit are investigated.Scanning Electron Microscope-Cathodoluminescence(SEMCL)observations reveal that Sch-A consists of three generations,with dark gray homogenous Sch-A1 being replaced by relatively lighter and homogeneous Sch-A2 and Sch-A3,with Sch-A2 displaying a gray CL image color with vague and uneven growth bands and Sch-A3 has a light gray CL image color with hardly any growth band.In contrast,Sch-B exhibits a‘core-rim’structure,with the core part(Sch-B1)being dark gray and displaying a uniform growth band,while the rim part(Sch-B2)is light gray and homogeneous.The normalized distribution pattern of rare earth elements in scheelite and Sr isotope data suggest that the early ore-forming fluid in the Nuri deposit originated from granodiorite porphyry and,later on,some country rock material was mixed in,due to strong water-rock interaction.Combining the O-H isotope data further indicates that the ore-forming fluid in the Nuri deposit originated from magmatic-hydrothermal sources,with contributions from metamorphic water caused by water-rock interaction during the mineralization process,as well as later meteoric water.The intense water-rock interaction likely played a crucial role in the precipitation of scheelite,leading to varying Eu anomalies in different generations of scheelite from the oxide stage to the quartz-sulfide stage,while also causing a gradual decrease in oxygen fugacity(fO2)and a slow rise in pH value.Additionally,the high Mo and low Sr contents in the scheelite are consistent with typical characteristics of magmatic-hydrothermal scheelite.Therefore,considering the geological features of the deposit,the geochemical characteristics of scheelite and the O-H isotope data published previously,it can be concluded that the genesis of the Nuri deposit belongs to porphyry-skarn deposit.展开更多
文摘The purpose of this study was to investigate the pollution level of trace metals As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sb, Se and Zn in agricultural soil around the water reservoir. A total of 36 soil samples were collected both during off-season agriculture and pluvial agriculture from April to October 2022. The samples were analyzed for trace metals according to the standard methods of the US EPA 2007 with a microwave plasma atomic emission spectrometer (MP-AES), Agilent Model 4210. The pollution level was assessed using contamination factor (Cf) and modified contamination degree (mCd). During the off-season, the concentration of trace metals followed in descending order as Mn > Cr > Cu > Pb > Zn. As, Cd, Co, Hg, Ni, Sb and Se were below the detectable limits. In pluvial season, the concentration of traces of metal follows the order Mn > Cr > Zn > Cu > Ni > Pb > Hg > As. Cd, Co, Sb and Se remain below the detectable limits. The concentrations of Cr, Mn and Zn were lower in the off-season agriculture than in pluvial agriculture. For Cu and Pb, the concentrations were higher in the off-season than in pluvial agriculture. The Cf ranges from 0.24 to 11.70 depending on the considered trace metal. The Cf values of As, Ni, Pb, Zn and Mn indicated that the agricultural study soil was lowery contaminated by these trace metals. The agricultural study soil was moderately contaminated by Cr and Cu, and highly contaminated by Hg. Globally the agricultural study soil presents a moderate degree of contamination (mCd 2.25) by the eight trace metals studied. This result provides information on understanding the risks of trace metal contamination of agricultural soil. It is important to anticipate the control of soil contamination through regular monitoring of toxic metals in agricultural soils, control the quality of chemicals used in agriculture and regulate their use.
文摘In this paper,we find some mistakes in the paper “Several Inequalities of Matrix Traces” which was published in Chinese Quarterly Journal of Mathematics,Vol.10,No.2.
基金supported by the National Natural Science Foundation of China(No.41304115)National Key S&T Special Projects(No.2016ZX050 24001-003)+2 种基金Open Fund for Sichuan Province Key Laboratory of Natural Gas Geology(No.2015trqdz02)the Research Project,CNPC(No.2016A-33)"Young and Middle-aged Key Teachers"Training Program in Southwest Petroleum University
文摘Currently, the selection of receiving traces in geometry design is mostly based on the horizontal layered medium hypothesis, which is unable to meet survey requirements in a complex area. This paper estimates the optimal number of receiving traces in field geometry using a numerical simulation based on a field test conducted in previous research （Zhu et al., 2011）. A mathematical model is established for total energy and average efficiency energy using fixed trace spacing and optimal receiving traces are estimated. Seismic data acquired in a complex work area are used to verify the correctness of the proposed method. Results of model data calculations and actual data processing show that results are in agreement. This indicates that the proposed method is reasonable, correct, sufficiently scientific, and can be regarded as a novel method for use in seismic geometry design in complex geological regions.
文摘This study was conducted during Dec2011-Nov2012 on three stations located in the south sector of Main Outfall Drain (MOD) River. Station 1 was near Al-Holandee Bridge which was the general carriage way in the center of Al-Nassiriya city, station 2 was 20 km far from the first station, while station 3 was in the beginning of the new branch. This study reveals the Seasonal Variation of Total petroleum hydrocarbons (TPHs) in both surface waters, sediment and it is related with trace metals nickel and vanadium in water (dissolved, particulate) and sediment (residual and exchangeable) phases. Also, the study shows the relationships between the concentration of Ni and V with Total Organic Carbon (TOC%) in the sediment.
基金the financial support from theRussian Foundation for Basic Research (projects #15-05-06197 and #18-05-01004)
文摘In this paper, the authors studied the traces of destruction in the fortress walls and houses of the Bosporan city of Kytaia. The study of this city has been ongoing since 1970. Over the past time, numerous damages have been identified at different sites of the ancient settlement. In the article, an attempt is made to compare some of them with the results of earthquakes on the Bosporus, about which the data of ancient authors were preserved.
文摘Emerging contaminants constitute a set of substances that are released into the environment for which regulations are currently not established for their environmental monitoring, being antimony one of them. A new methodology for Sb(III) traces monitoring by solid surface fluorescence is proposed. The metal was complexed with alizarine (Az) as fluorosphore reagent in alcaline medium in presence of the bile salt sodium cholate. To isolate the analyte of matrix constituents, a preconcentration/separation strategy on filter paper was introduced prior to determination step. The solid surface fluorescence was measured λem = 450 nm and λexc = 363 nm using a solid sampler holder. Under optimal conditions, the limits of detection and quantification of proposed methodology were 0.08 and 0.24 μg·L-1, respectively, showing a linear range from 0.24 to 304.4 μg·L-1 with good sensitivity and adequate selectivity. It was applied to the Sb(III) traces determination present in drinking water and beverages samples packaged in polyethylene terephthalate (PET) bottles widely consumed in Argentina. The combination of a preconcentration step on common filter paper and the inherent sensitivity of photoluminescent methods have permitted to achieve sensitivity similar to atomic spectroscopies using a lower price instrument typical in control laboratories. Precision and accuracy were tested with excellent agreement. Results were truenessed by ETAAS with satisfactory concordance.
文摘The disposal of urban or hospital waste in open landfills is the easiest way to throw back of them without environmental concerns. MTEs （Metal Trace Elements） are the most toxic mineral elemems. This study evaluates the impact of MTE on a neighboring human population or playing near a municipal dump. Two panels were composed of adult men and children （males under sixteen years old）. Four trace metal elements were analyzed： copper, lead, cadmium and zinc. The site of the study was the municipal waste dump in Marrakech （Morocco）. The results reveal abnormal concentrations of these MTEs in blood and hair of adults and children.
文摘Surfactant enhanced chemofiltration on Nylon membranes pre-treated with hexadecyltrimethylammonium bromide (HTAB) and eosin dye (eo) is proposed for zinc traces quantification by solid surphase spectro- fluorimetry (SSF, λexc = 532 nm;λem = 548 nm). Operational variables which have influence on quantitative retention of metal complex have been studied and optimized. At optimal experimental conditions, quantita- tive recovery was reached with a detection limit of 0.662 pg?L–1 and quantification limit of 2.20 pg?L–1. The calibration sensitivity was of 1.22 L?pg–1 for the new methodology with a linear range of 2.20 pg?L–1 to 779 pg?L–1 Zn (II). The tolerance levels of potential interfering ions were studied with good results. Recuperation studies were carried out by standard addition method applied to natural water samples (San Juan, Argentine) without previous treatment. The reproducibility (between-days precision) was also evaluated over 3 days by performing five determinations each day. CV% was 0.37. The performing obtained in sensitivity and selec- tivity thanks to chemofiltration step, converts the proposed methodology in an adequate alternative to con- ventional techniques for Zn (II) traces determination.
文摘IEA-R1 nuclear reactor operation has the routine to control uranium content in pool water to be in trace range below 50 μg/L. There are several routes to determine the uranium trace content in water in the literature;voltammetry has been systematically employed. In the present study, the chosen chemical determination of uranium traces used the voltammetric method known as AdCSV (adsorptive cathodic stripping voltammetry). This technique, based on mercury voltammetry, is an adequate methodology to determine uranium traces. The chloranilic acid [CAA] (2,5-dichloro-3,6-dihydroxy-1,4-benzo-quinone) is indicated as chelating agent. The redox reaction of UO2+2?with CAA is sensitive in the range of 2 2(CAA)2] reduction potential. In this work, we present the uranium trace results for IEA-R1 reactor water, sampled after an operation routine shutdown. The uranium trace determination for IEA-R1 pool water showed content around 1 μg/L [U] with statistical significance. Therefore the IEA-R1-reactor-water purification showed to be adequate and safe.
文摘The aim of this work has been to evaluate the aluminium (Al(III)) traces contents in 24-hour urine samples from subjects with different tobacco smoke expositions using a new methodology with 1,4-dihydroxy-9, 10-anthraquinone (Quinizarine, QZ) as a fluorosphore. Biological samples were tested using commercial reagent strips and clinical parameters. Al(III) was determined complexing with QZ followed by a solid phase extraction step using Nylon membranes as a solid support. The analyte was subsequently quantified by solid surface fluorescence (SSF, λem= 573, λexc= 490) with a detection limit of 0.88 μg L-1 and quantification limit of 2.69 μg L-1. The calibration curve was linear from 2.69 to 499.13 μg L-1 Al(III) (R2 = 0.9973). Urine samples were successfully analysed with an average recovery close to 100%. Solid phase extraction step showed efficacy to eliminate foreign ions and the highly fluorescent matrix own of urine. Results were validated by electrothermal atomic absorption spectrometry (ETAAS) with an adequate concordance. The new methodology has low operation cost with simple instrumentation and without organic solvent.
文摘A new fluorescence silver nanosensor assisted by surfactant has been synthesized and applied to ultra trace nickel determination. Operational variables which influence nanomaterial synthesis have been studied and optimized. Synthesis was very fast and simple using non polluting solvents; silver chemical reduction was carried out at room temperature. Spectroscopic studies were carried out in order to assure the uniformed of nanomaterial obtained. Fluorescent signal of silver nanoparticles resulted enhanced in presence of Ni（II）. At optimal experimental conditions, a detection limit of 0.036 pg＇L1 and quantification limit 0.12 pg＇L~ were obtained. The calibration sensitivity was 2 x 1014 L.pg-l.cm1 for the new methodology, with a range of linearity of six orders of magnitude between 0.12 and 2.93 × 10^5 pg L^-1. The tolerance levels for potential interferent ions were studied with good results. The proposed methodology represents a promising approach for Ni（II） traces quantification due to its low operation cost, simplicity of instrumentation, high sampling speed and non-polluting solvents.
基金Funded by National Natural Science Foundation of China(No.51401226)
文摘For TA15 titanium alloy, slip is the dominant plastic deformation mechanism because of relatively high Al content. In order to reveal the grain-scale stress field and geometrically necessary dislocation（GND） density distribution around the slip traces and phase boundaries where the slip lines are blocked due to Burgers orientation relationship（OR） missing. We experimentally investigated tensile deformation on TA15 titanium alloy up to 2.0% strain at room temperature. The slip traces were observed and identified using high resolution scanning electron microscopy（SEM） and electron backscatter diffraction（EBSD） measurements. The grain-scale stress fields around the slip traces and phase boundaries were calculated by the cross-correlationbased method. Based on strain gradient theories, the density of GND was calculated and analyzed. The results indicate that the grain-scale stress is significantly concentrated at phase/grain boundaries and slip traces. Although there is an obvious GND accumulation in the vicinity of phase and subgrain boundaries, no GND density accumulation appears near the slip traces.
基金The study is supported by the National Natural Science Foundation of China( No.49472 0 86) the Key Science and Technology Pro
文摘On the basis of topological criteria, metazoan traces can be classified as four ichnoorders (clusters) and twenty two ichnofamilies (kinds), which consist of nine basic and three combined topological configurations. At a topological level, the behavioral diversity and complexity indicated by metazoan traces have remained quite stable since the Early Cambrian. Dramatic changes of these traits took place in the Neoproterozoic, in which 75% (12/16) of the topoichnotaxa and all nine basic topological configurations of metazoan traces occurred, but the most complex and highest level topological configuration occurred in the Early Cambrian of the coelomate animal explosive evolution, showing that in the Neoproterozoic and Early Cambrian gestated not only the Ediacarian fauna and all the basic types of multi cellular animals known today, but also all the basic and the most complex metazoan traces through geological time.
文摘The application of reinforcement learning is widely used by multi-agent systems in recent years. An agent uses a multi-agent system to cooperate with other agents to accomplish the given task, and one agent′s behavior usually affects the others′ behaviors. In traditional reinforcement learning, one agent takes the others location, so it is difficult to consider the others′ behavior, which decreases the learning efficiency. This paper proposes multi-agent reinforcement learning with cooperation based on eligibility traces, i.e. one agent estimates the other agent′s behavior with the other agent′s eligibility traces. The results of this simulation prove the validity of the proposed learning method.
文摘In this paper we derive some inequalities for traces and singular values of the quaternion matrices,extend and improve some of the corresponding results appeared in other papers we know.
基金supported by the National Natural Science Foundation of China(Nos.62173229,12288201)the Australian Research Council Future Fellowship Funding Scheme under Project FT220100656 and the Discovery Project Funding Scheme under Project DP210101938.
文摘The task to estimate all the parameters of an unknown quantum state, also called quantum state tomography, is essential for characterizing and controlling quantum systems. In this paper, we utilize observable time traces to identify the initial quantum state of a closed quantum system, based on the state space approach in the control theory. In the informationally complete scenario, we show that with a linear regression estimation (LRE), the mean squared error (MSE) scales as , where N is the resource number. In the informationally incomplete scenario, we introduce regularization LRE to perform the state tomography task. We employ PBH test to demonstrate that closed quantum systems with only one observable are informationally incomplete and propose using observables, where d is the dimension of the quantum state, for informational completeness. Numerical examples demonstrate the effectiveness of our method.
基金partly supported by NNSF of China(Grant No.11822105)partly supported by NNSF of China(Grant Nos.12071121 and 11720101003)supported by NNSF of China(Grant No.12101226)。
文摘In this paper,we study the traces and the extensions for weighted Sobolev spaces on upper half spaces when the weights reach to the borderline cases.We first give a full characterization of the existence of trace spaces for these weighted Sobolev spaces,and then study the trace parts and the extension parts between the weighted Sobolev spaces and a new kind of Besov-type spaces(on hyperplanes)which are defined by using integral averages over selected layers of dyadic cubes.
基金supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT)(No. 2021R1I1A1A0105621313, No. 2022R1F1A1074441, No. 2022K1A3A1A20014496, and No. 2022R1F1A1074083)supported by the Ministry of Education Funding (No. RIS 2021-004)supported by the Brain Pool program funded by the Ministry of Science and ICT through the National Research Foundation of Korea (RS-2023-00284318).
文摘In this study,precise control over the thickness and termination of Ti3C2TX MXene flakes is achieved to enhance their electrical properties,environmental stability,and gas-sensing performance.Utilizing a hybrid method involving high-pressure processing,stirring,and immiscible solutions,sub-100 nm MXene flake thickness is achieved within the MXene film on the Si-wafer.Functionalization control is achieved by defunctionalizing MXene at 650℃ under vacuum and H2 gas in a CVD furnace,followed by refunctionalization with iodine and bromine vaporization from a bubbler attached to the CVD.Notably,the introduction of iodine,which has a larger atomic size,lower electronegativity,reduce shielding effect,and lower hydrophilicity(contact angle:99°),profoundly affecting MXene.It improves the surface area(36.2 cm^(2) g^(-1)),oxidation stability in aqueous/ambient environments(21 days/80 days),and film conductivity(749 S m^(-1)).Additionally,it significantly enhances the gas-sensing performance,including the sensitivity(0.1119Ωppm^(-1)),response(0.2% and 23%to 50 ppb and 200 ppm NO_(2)),and response/recovery times(90/100 s).The reduced shielding effect of the–I-terminals and the metallic characteristics of MXene enhance the selectivity of I-MXene toward NO2.This approach paves the way for the development of stable and high-performance gas-sensing two-dimensional materials with promising prospects for future studies.
基金financially supported by the National Key Research and Development Program of China(Grant No.2021YFC2901903)the Geological Comprehensive Research Project of China’s Metallurgical Geology Bureau(Grant No.[2022]CMGBDZYJ005),the National Natural Science Foundation of China(Grant No.42002097)the Geological Investigation Project(Grant Nos.DD20230031,DD20221690,DD20230049,DD20230337).
文摘The Nuri deposit is the only Cu-W-Mo polymetallic deposit with large-scale WO3 resources in the eastern section of the Gangdese metallogenic belt,Tibet,China.However,the genetic type of this deposit has been controversial since its discovery.Based on a study of the geological characteristics of the deposit,this study presents mineralization stages,focusing on the oxide stage and the quartz-sulfide stage where scheelite is mainly formed,referred to as Sch-A and Sch-B,respectively.Through LA-ICP-MS trace element and Sr isotope analyses,the origin,evolutionary process of the oreforming fluid and genesis of the ore deposit are investigated.Scanning Electron Microscope-Cathodoluminescence(SEMCL)observations reveal that Sch-A consists of three generations,with dark gray homogenous Sch-A1 being replaced by relatively lighter and homogeneous Sch-A2 and Sch-A3,with Sch-A2 displaying a gray CL image color with vague and uneven growth bands and Sch-A3 has a light gray CL image color with hardly any growth band.In contrast,Sch-B exhibits a‘core-rim’structure,with the core part(Sch-B1)being dark gray and displaying a uniform growth band,while the rim part(Sch-B2)is light gray and homogeneous.The normalized distribution pattern of rare earth elements in scheelite and Sr isotope data suggest that the early ore-forming fluid in the Nuri deposit originated from granodiorite porphyry and,later on,some country rock material was mixed in,due to strong water-rock interaction.Combining the O-H isotope data further indicates that the ore-forming fluid in the Nuri deposit originated from magmatic-hydrothermal sources,with contributions from metamorphic water caused by water-rock interaction during the mineralization process,as well as later meteoric water.The intense water-rock interaction likely played a crucial role in the precipitation of scheelite,leading to varying Eu anomalies in different generations of scheelite from the oxide stage to the quartz-sulfide stage,while also causing a gradual decrease in oxygen fugacity(fO2)and a slow rise in pH value.Additionally,the high Mo and low Sr contents in the scheelite are consistent with typical characteristics of magmatic-hydrothermal scheelite.Therefore,considering the geological features of the deposit,the geochemical characteristics of scheelite and the O-H isotope data published previously,it can be concluded that the genesis of the Nuri deposit belongs to porphyry-skarn deposit.
