The oxidation behavior of three biodiesels of different origins,viz.rapeseed oil derived biodiesel,soybean oil derived biodiesel and waste oil based biodiesel,were tested on an oxidation tester.The chemical compositio...The oxidation behavior of three biodiesels of different origins,viz.rapeseed oil derived biodiesel,soybean oil derived biodiesel and waste oil based biodiesel,were tested on an oxidation tester.The chemical compositions of the biodiesels were characterized by gas chromatography.Thereafter,the structural transformation of fatty acid methyl ester(FAME)of the biodiesels was analyzed by an infrared spectrometer and an ultraviolet absorption spectrometer.The results demonstrated that the oxidation behavior of biodiesels of different origins was closely related to the composition and distribution of FAMEs.Higher concentration of unsaturated FAME with multi-double bonds exhibited poorer oxidation resistance.Furthermore,cis-trans isomerization transformation occurred in the unsaturated FAME molecules and conjugated double-bond produced during the oxidation process of biodiesel.Greater cis-trans variations corresponded to deeper oxidation degree.The higher the content of unsaturated FAME with multi-double bonds in a biodiesel,the more the conjugated double bonds was formed.展开更多
We applied near-infrared(NIR)spectroscopy with chemometrics for the rapid and reagent-fee analysis of serum urea nitrogen(SUN).The modeling is based on the average effect of multiple sample partitions to achieve param...We applied near-infrared(NIR)spectroscopy with chemometrics for the rapid and reagent-fee analysis of serum urea nitrogen(SUN).The modeling is based on the average effect of multiple sample partitions to achieve parameter selection with stability.A multiparameter optimization platform with Norris derivative filter-partial least squares(Norris-PLS)was developed to select the most suitable mode(d=2,s=33,g=15).Using equidistant combination PLS(EC-PLS)with four parameters(initial wavelength I,number of wavelengths N,number of wavelength gaps G and latent variables LV),we performed wavelength screening after eliminating high-absorption wavebands.The optimal EC-PLS parameters were I=1228 nm,N=26,G=16 and LV=12.The root-mean square error(SEP),correlation coefficient(R_(p))for prediction and ratio of performance-to-deviation(RPD)for validation were 1.03 mmol L^(-1),0.992 and 7.6,respectively.We proposed the wavelength step-by-step phase-out PLS(WSP-PLS)to remove redun-dant wavelengths in the top 100 EC-PLS models with improved prediction performance.The combination of 19 wavelengths was identifed as the optimal model for SUN.The SEP,Rp and RPD in validation were 1.01 mmol L^(-1),0.992 and 7.7,respectively.The prediction effect and wavelength complexity were better than those of EC-PIS.Our results showed that NIR spectroscopy combined with the EC-PLS and WSP-PLS methods enabled the high-precision analysis ofSUN.WSP-PLS is a secondary optimization method that can further optimize any wavelength moc odel obtained through other continuous or discrete strategies to establish a simple and better model.展开更多
The leaching of cobalt from four-mixed Co-Cu oxidized ores containing cobalt at levels ranging from 0.5wt% to 34wt% was studied and the results has been reported. Conventional dissolution of these oxidized Co-Cu ores ...The leaching of cobalt from four-mixed Co-Cu oxidized ores containing cobalt at levels ranging from 0.5wt% to 34wt% was studied and the results has been reported. Conventional dissolution of these oxidized Co-Cu ores with diluted H2SO4 and SO2 as a reducing agent resulted in a substantial improvement in the solution based recovery of cobalt. UV/visible spectroscopic analysis of the leached solu-tions indicated that the increased cobalt content in the solution was a result of flushing the acidified cobalt leaching solution with SO2. Fur-thermore, UV/visible spectroscopy confirmed that as SO2 was flushed into the acidified leaching solution, Co3＋ bearing minerals were re-duced to the readily soluble Co2＋ bearing minerals, and this resulted in the increase of total cobalt in the collected solution. The mechanism of the reduction of Co3＋ to Co2＋ bearing minerals when SO2 is flushed during the leaching of mixed Co-Cu oxidized ores, including the stability trends of Co3＋, Co2＋, and Cu2＋ complexes, as shown by their UV/visible spectra, are also discussed.展开更多
It is well known that boron exists as polyborate anions in aqueous solution.Boron atom can coordinates to three or four oxygen atoms and borate can exist as not only the monomer but also the polymer.The polymerization
1 Introduction In recent years,the study has found that spherical graphite has a high charge and discharge capacity and electrochemical stability,is the ideal lithium battery anodematerial and important ultra-high cap...1 Introduction In recent years,the study has found that spherical graphite has a high charge and discharge capacity and electrochemical stability,is the ideal lithium battery anodematerial and important ultra-high capacitor material,with a high cost performance(Chuan et al,2012).Spherical展开更多
Several key problems involved in the analyses of spectra of asymmetric top molecules, i.e., the effective Hamiltonian, the representation and basis vector, identification of energy levels, the selection rules, the rel...Several key problems involved in the analyses of spectra of asymmetric top molecules, i.e., the effective Hamiltonian, the representation and basis vector, identification of energy levels, the selection rules, the relative intensity, and Zeeman tuning rate, were elucidated systematically. Introducing the high-order centrifugal distortion terms into the effective Hamiltonian, the precision for calculation has been improved substantially, which allows us to analyze the high-lying rotational transitions. A global analysis of all available spectra of 14N16O2 in the ground vibronic state has been made to obtain a set of molecular constants of 14N16O2 in the ground vibronic state which is the most precise and extensive so far. Using the improved parameters, some FIR LMR lines left unassigned hitherto have been identified successfully.展开更多
Phytochemical investigation of the branches of Viburnum awabuki K.Koch led to the isolation of thirteen known compounds,including five lignans(1-5),one phytosterol(6),two phenylpropanoids(7-8),one chromone derivative(...Phytochemical investigation of the branches of Viburnum awabuki K.Koch led to the isolation of thirteen known compounds,including five lignans(1-5),one phytosterol(6),two phenylpropanoids(7-8),one chromone derivative(9),three pentacyclic triterpenoids(10-12),and one glyceride(13).The structures of these compounds were elucidated through extensive spectroscopic analyses and comparison of experimental data with literature data.Additionally,the chemotaxonomic significance of the isolated secondary metabolites was also discussed.展开更多
A large amount of wastewater containing various toxic organic contaminants is produced during coal-to-liquids process. In this study, several spectroscopic methods were used to monitor the transformation of organic po...A large amount of wastewater containing various toxic organic contaminants is produced during coal-to-liquids process. In this study, several spectroscopic methods were used to monitor the transformation of organic pollutants during an integrated chemical oxidation and biological process. The results showed that the hydrophobic acid fraction increased after Fenton oxidation, which was likely due to the production of small-molecule organic acids. Soluble microbial products were generated during biological treatment processes,which were degraded after ozonation; meanwhile, the hydrophilic base and acid components increased. Ultraviolet-visible spectroscopic analysis indicated that peaks at the absorption wavelengths of 280 and 254 nm, which are associated with aromatic substances, were detected in the raw water. The aromatic substances were gradually removed, becoming undetectable after biological aeration filter（BAF） treatment. Fourier transform infrared spectroscopy analysis revealed that the functional groups of phenols;benzene, toluene, ethylbenzene, and xylene（BTEX）; aromatic hydrocarbons; aliphatic acids;aldehydes; and esters were present in raw wastewater. The organic substances were oxidized into small molecules after Fenton treatment. Aromatic hydrocarbons were effectively removed through bioadsorption and biodegradation after BAF process.Biodegradable organic matter was reduced and finally became undetectable after anoxic–oxic treatment in combination with a membrane bioreactor. Four fluorescent components were fractionated and obtained via excitation–emission matrix parallel factor analysis（EEM-PARAFAC）. Dissolved organic matter fractionation in conjunction with EEM-PARAFAC was able to monitor more precisely the evolution of characteristic organic contaminants.展开更多
Emblic medicine is a popular natural source in the world due to its outstanding healthcare and therapeutic functions.Our preliminary results indicated that the quality of emblic medicines might have an apparent region...Emblic medicine is a popular natural source in the world due to its outstanding healthcare and therapeutic functions.Our preliminary results indicated that the quality of emblic medicines might have an apparent regional variation.A rapid and effective geographical traceability system has not been designed yet.To trace the geographical origins so that their quality can be controlled,an integrated spectroscopic strategy including spectral pretreatment,outlier diagnosis,feature selection,data fusion,and machine learning algorithm was proposed.A featured data matrix(245220)was successfully generated,and a carefully adjusted RF machine learning algorithm was utilized to develop the geographical traceability model.The results demonstrate that the proposed strategy is effective and can be generalized.Sensitivity(SEN),specificity(SPE)and accuracy(ACC)of 97.65%,99.85%and 97.63%for the calibrated set,as well as 100.00%predictive efficiency,were obtained using this spectroscopic analysis strategy.Our study has created an integrated analysis process for multiple spectral data,which can achieve a rapid,nondestructive and green quality detection for emblic medicines originating from seventeen geographical origins.展开更多
Near-infrared (NIR) spectroscopy was applied to reagent-free quantitative analysis of polysaccharide of a brand product of proprietary Chinese medicine (PCM) oral solution samples. A novel method, called absorbance up...Near-infrared (NIR) spectroscopy was applied to reagent-free quantitative analysis of polysaccharide of a brand product of proprietary Chinese medicine (PCM) oral solution samples. A novel method, called absorbance upper optimization partial least squares (AUO-PLS), was proposed and successfully applied to the wavelength selection. Based on varied partitioning of the calibration and prediction sample sets, the parameter optimization was performed to achieve stability. On the basis of the AUO-PLS method, the selected upper bound of appropriate absorbance was 1.53 and the corresponding wavebands combination was 400 - 1880 & 2088 - 2346 nm. With the use of random validation samples excluded from the modeling process, the root-mean-square error and correlation coefficient of prediction for polysaccharide were 27.09 mg·L<sup>-</sup><sup>1</sup> and 0.888, respectively. The results indicate that the NIR prediction values are close to those of the measured values. NIR spectroscopy combined with AUO-PLS method provided a promising tool for quantification of the polysaccharide for PCM oral solution and this technique is rapid and simple when compared with conventional methods.展开更多
The moving window bis corelation coefficients(MW BiCC)was proposed and employed for the discriminant analysis of transgenic sugarcane leaves and B-thalassemia with visible and near-infrared(Vis NIR)spectroscopy.The we...The moving window bis corelation coefficients(MW BiCC)was proposed and employed for the discriminant analysis of transgenic sugarcane leaves and B-thalassemia with visible and near-infrared(Vis NIR)spectroscopy.The well-performed moving window principal component analysis linear discriminant analysis(MWPCA-LDA)was also conducted for comparison.A total of 306 transgenic(positive)and 150 nont ransgenic(negative)leave samples of sugarcane were collected and divided to calibration,prediction,and validation.The diffuse reflection spectra were corected using Savitzky-Golay(SG)smoothing with first-order derivative(d=1),third-degree polynomial(p=3)and 25 smpothing points(m=25).The selected waveband was 736-1054nm with MW-BiCC,and the positive and negative validation recognition rates(V_REC^(+),VREC^(-))were 100%,98.0%,which achieved the same effect as MWPCA-LDA.Another example,the 93 B-thalassemia(positive)and 148 nonthalassemia(negative)of human hemolytic samples were colloctod.The transmission spectra were corrected using SG smoothing withd=1,p=3 and m=53.Using M W-BiCC,many best wavebands were selected(e.g.,1116-1146,17941848 and 22842342nm).The V_REC^(+)and V_REC^(-)were both 100%,which achieved the same effect as MW-PCA-LDA.Importantly,the BICC only required ca lculating correlation cofficients between the spectrum of prediction sample and the average spectra of two types of calibration samples.Thus,BiCC was very simple in algorithm,and expected to obtain more applications.The results first confirmed the feasibility of distinguishing B-thalassemia and normal control samples by NIR spectroscopy,and provided a promising simple tool for large population thalassemia screening.展开更多
The Andromeda galaxy was observed by the Guoshoujing Telescope （formerly named the Large Sky Area Multi-Object Fiber Spectroscopic Telescope -- LAMOST）, during the 2009 commissioning phase. Due to the absence of sta...The Andromeda galaxy was observed by the Guoshoujing Telescope （formerly named the Large Sky Area Multi-Object Fiber Spectroscopic Telescope -- LAMOST）, during the 2009 commissioning phase. Due to the absence of standard stars for flux calibration, we use the photometric data of 15 intermediate bands in the Beijing-Arizona-Taipei-Connecticut （BATC） survey to calibrate the spectra. In to- tal, 59 spectra located in the bulge and disk of the galaxy are obtained. Kinematic and stellar population properties of the stellar content are derived with these spectra. We obtain the global velocity field and calculate corresponding rotation velocities out to about 7 kpc along the major axis. These rotation velocity measurements comple- ment those of the gas content, such as the H I and CO. The radial velocity dispersion shows that the stars in the bulge are more dynamically thermal and the disk is more rotationally-supported. The age distribution shows that the bulge was formed about 12 Gyr ago, the disk is relatively younger and the ages of some regions along the spi- ral arms can reach as young as about 1 Gyr. These young stellar populations have a relatively richer abundance and larger reddening. The overall average metallicity of the galaxy approximates the solar metallicity and a very weak abundance gradient is gained. The reddening map gives a picture of a dust-free bulge and a distinct dusty ring in the disk.展开更多
The spectra of HeI（587.6 nm）,Hα（656.28 nm） and Dα（656.1 nm） of the helium discharges as well as the normal deuterium discharges have been measured with two optical spectroscopic multi-channel analysis（OMA） s...The spectra of HeI（587.6 nm）,Hα（656.28 nm） and Dα（656.1 nm） of the helium discharges as well as the normal deuterium discharges have been measured with two optical spectroscopic multi-channel analysis（OMA） systems on the experimental advanced superconducting tokamak（EAST）.The influx ratio of the sum of H and D to He spectral lines and the influx ratio of H to D are given.In this way the ratio of hydrogen/deuterium ion（S/X B）H/D to（S/X B）He as well as（S/X B）H/D is not very sensitive to the variation in the edge density and temperature. The low-density helium discharges are operated in order to reduce the recycling hydrogen fluxes; however,the effect is not obvious.The possible reason is that the number of helium discharges is not enough and the content of hydrogen in the wall is still very abundant,which is caused by frequent wall conditionings and the vacuum leakage.The H/（H＋D） ratio decreases quickly after one lithium coating and reduces to less than 10%using several accumulated lithium wall conditioning.It is found that the deposited He atoms on the carbon wall will remain at a low level after several D2 discharges.展开更多
The process of accurately defining and outlining mare basalt units is nec- essary for constraining the stratigraphy and ages of basalt units, which are used to determine the duration and the flux of lunar volcanism. W...The process of accurately defining and outlining mare basalt units is nec- essary for constraining the stratigraphy and ages of basalt units, which are used to determine the duration and the flux of lunar volcanism. We use a combination of Clementine＇s five-band ultraviolet/visible data and Ti02 and FeO abundance distri- bution maps to define homogenous mare basalt units and characterize their composi- tional variations （with maturity） in the Aristarchus region. With 20 groups of distinct mare basaltic soils identified using the method in this paper, six additional spectrally defined areas and five basaltic units are constructed, and their mineralogic quanfiza- tion values provide new constraints on their temporal and spatial evolution. Our results indicate that the Aristarchus region has diverse basalt units and a complex history of volcanic evolution. We also demonstrate that the techniques, from which spectrally distinct mare basalts can be mapped, performed well in this study and can be confi- dently expanded to other mare regions of the Moon.展开更多
The advances in transmission electron microscopy(TEM)have greatly improved the characterization of heterogeneous catalysts,offering valuable insights into their operational efficacy through the correlation of their ph...The advances in transmission electron microscopy(TEM)have greatly improved the characterization of heterogeneous catalysts,offering valuable insights into their operational efficacy through the correlation of their physicochemical characteristics with performance,specificity,and robustness at nanoscales.Understanding tangible catalyst attributes and corresponding catalytic processes necessitates the identification and rationalization of catalyst behavior modifications during reaction conditions.Recent innovations in in-situ TEM techniques have opened new avenues to observe the progress of heterogeneous catalysis with unparalleled spatial precision,superior energy resolution,and precise temporal resolution in controlled or realistic catalytic environments.Herein,we have reviewed the established and evolving techniques for monitoring catalysts through the utilization of in-situ TEM.By combining in-situ TEM with cutting-edge spectroscopic methodologies like atomic electron tomography(AET),4D-STEM,cryogenic electron microscopy,and monochromated electron energy loss spectroscopy(EELS),a comprehensive approach to catalyst observation is achieved.Likewise,this advancement is expected to highlight and expand the crucial role of in-situ TEM in elucidating catalyst surface structures,active sites,and reaction pathways across key catalytic reactions,shaping the field of research in heterogeneous catalysis.Finally,the potential applications,advantages,and challenges of using in-situ TEM are emphasized and addressed in detail.展开更多
Twenty-three progressive extractions were performed to study individual humic acids (HAs) and humin fractions from a typical black soil (Mollisol) in Heilongjiang Province, China using elemental analysis and spectrosc...Twenty-three progressive extractions were performed to study individual humic acids (HAs) and humin fractions from a typical black soil (Mollisol) in Heilongjiang Province, China using elemental analysis and spectroscopic techniques. After 23 HA extractions the residue was separated into high and low organic carbon humin fractions. HA yield was the highest for the first extraction and then gradually decreased with further extractions. Organic carbon (OC) of the humin fractions accounted for 58% of total OC …展开更多
The laser induced breakdown spectroscopy(LIBS) is an element analysis technique with the advantages of real time detection,simultaneous multi-element identification,and in-situ and stand-off capacities.To evaluate its...The laser induced breakdown spectroscopy(LIBS) is an element analysis technique with the advantages of real time detection,simultaneous multi-element identification,and in-situ and stand-off capacities.To evaluate its potential of ocean applications,in this paper,the time resolved laser-induced breakdown spectroscopy for calcium concentration detection in water is investigated.With the optimum experimental parameters,the plasma emission lifetime is determined to be about 500 ns with 532 nm laser excitation,and 1000 ns with 1064 nm laser excitation.The lowest detection concentration of 50 ppm is achieved for calcium detection in CaCl2 water solution using the 532 nm LIBS.Even better detection sensitivity is achieved using the 1064 nm LIBS,and the resulted lowest detection concentration of calcium is 25 ppm.The results suggest that it is feasible to develop LIBS as an on-line sensor for metal element monitoring in the sea.展开更多
Three new secoiridoid glycosides,named lonijapoglycol A(1),aldosecolohanin C(2)and aldosecolohanin B(3),together with three known ones(4–6),have been isolated from the flower the buds of Lonicera japonica.All the str...Three new secoiridoid glycosides,named lonijapoglycol A(1),aldosecolohanin C(2)and aldosecolohanin B(3),together with three known ones(4–6),have been isolated from the flower the buds of Lonicera japonica.All the structures were identified by spectroscopic analyses.Lonijapoglycol A(1)expressed significant anti-inflammatory activity to inhibit the release ofβ-glucuronidase induced by platelet-activating factor in rat polymorphonuclear leukocytes with an IC50 value of 3.76μmol·L^-1.展开更多
The radionuclide(RN)migration study is not only helpful to understand environmental behavior of RNs,but also can establish the basis for the safety assessment of geological disposal of high-level radioactive waste(HLW...The radionuclide(RN)migration study is not only helpful to understand environmental behavior of RNs,but also can establish the basis for the safety assessment of geological disposal of high-level radioactive waste(HLW).In the context of China’s HLW disposal,this review briefly summaries the progress of China’s RN migration studies over the past decade regarding three aspects,RN sorption,RN transport and radioactive colloid.Domestic studies from other disciplines(such as geology and environmental science)are also included in this review because they can provide references for the RN migration study.Overall,China has achieved clear progress in RN migration study over the past decade,although large-scaled field experiments are lacked and a gap still exists comparing with the international advanced level.Finally,several suggestions are proposed for future RN migration research in China.展开更多
Strongly Mg-enhanced stars with [Mg/Fe] 〉 1.0 show peculiar abundance patterns and hence are of great interest for our understanding of stellar formation and chemical evolution of the Galaxy. A systematic search for ...Strongly Mg-enhanced stars with [Mg/Fe] 〉 1.0 show peculiar abundance patterns and hence are of great interest for our understanding of stellar formation and chemical evolution of the Galaxy. A systematic search for strongly Mg-enhanced stars based on low-resolution （R≈2000） spectra from the Sloan Digital Sky Survey （SDSS） is carried out by finding the synthetic spectrum that best matches the observed one in the region of Mg I b lines around λ5170 ,A via a profile matching method. The advantage of our method is that fitting parameters are refined by reproducing the [Mg/Fe] ratios of 47 stars from the very precise high-resolution spectroscopic （HRS） analysis by Nissen ＆ Schuster; and these parameters are crucial to the precision and validity of the derived Mg abundances. As a further check of our method, Mg abun- dances are estimated with our method for member stars in four Galactic globular clus- ters （M92, M 13, M3, M71） which cover the same metallicity range as our sample, and the results are in good agreement with those of HRS analysis in the literature. The val- idation of our method is also demonstrated by the agreement of [Mg/Fe] between our values and those of HRS analysis by Aoki et al. Finally, 33 candidates of strongly Mg- enhanced stars with [Mg/Fe]〉 1.0 are selected from 14 850 F and G stars. Follow-up observations will be carried out on these candidates with high-resolution spectroscopy by large telescopes in the near future, so as to check our selection procedure and to perform a precise and detailed abundance analysis and to explore the origins of these stars.展开更多
基金the financial support from the National Natual Science Foundation of China(No.51375491)the Natural Science Foundation of Chongqing(Project No.2011JJA90020)the Science Foundation for Young Teachers of Logistical Engineering University
文摘The oxidation behavior of three biodiesels of different origins,viz.rapeseed oil derived biodiesel,soybean oil derived biodiesel and waste oil based biodiesel,were tested on an oxidation tester.The chemical compositions of the biodiesels were characterized by gas chromatography.Thereafter,the structural transformation of fatty acid methyl ester(FAME)of the biodiesels was analyzed by an infrared spectrometer and an ultraviolet absorption spectrometer.The results demonstrated that the oxidation behavior of biodiesels of different origins was closely related to the composition and distribution of FAMEs.Higher concentration of unsaturated FAME with multi-double bonds exhibited poorer oxidation resistance.Furthermore,cis-trans isomerization transformation occurred in the unsaturated FAME molecules and conjugated double-bond produced during the oxidation process of biodiesel.Greater cis-trans variations corresponded to deeper oxidation degree.The higher the content of unsaturated FAME with multi-double bonds in a biodiesel,the more the conjugated double bonds was formed.
基金supported by the Science and Technology Project of Guangdong Province of China(Nos.2014A020213016,2014A020212445)the University-enterprise Joint Research Project"Intelligent detection network technology joint research centre"(No.40115031).
文摘We applied near-infrared(NIR)spectroscopy with chemometrics for the rapid and reagent-fee analysis of serum urea nitrogen(SUN).The modeling is based on the average effect of multiple sample partitions to achieve parameter selection with stability.A multiparameter optimization platform with Norris derivative filter-partial least squares(Norris-PLS)was developed to select the most suitable mode(d=2,s=33,g=15).Using equidistant combination PLS(EC-PLS)with four parameters(initial wavelength I,number of wavelengths N,number of wavelength gaps G and latent variables LV),we performed wavelength screening after eliminating high-absorption wavebands.The optimal EC-PLS parameters were I=1228 nm,N=26,G=16 and LV=12.The root-mean square error(SEP),correlation coefficient(R_(p))for prediction and ratio of performance-to-deviation(RPD)for validation were 1.03 mmol L^(-1),0.992 and 7.6,respectively.We proposed the wavelength step-by-step phase-out PLS(WSP-PLS)to remove redun-dant wavelengths in the top 100 EC-PLS models with improved prediction performance.The combination of 19 wavelengths was identifed as the optimal model for SUN.The SEP,Rp and RPD in validation were 1.01 mmol L^(-1),0.992 and 7.7,respectively.The prediction effect and wavelength complexity were better than those of EC-PIS.Our results showed that NIR spectroscopy combined with the EC-PLS and WSP-PLS methods enabled the high-precision analysis ofSUN.WSP-PLS is a secondary optimization method that can further optimize any wavelength moc odel obtained through other continuous or discrete strategies to establish a simple and better model.
文摘The leaching of cobalt from four-mixed Co-Cu oxidized ores containing cobalt at levels ranging from 0.5wt% to 34wt% was studied and the results has been reported. Conventional dissolution of these oxidized Co-Cu ores with diluted H2SO4 and SO2 as a reducing agent resulted in a substantial improvement in the solution based recovery of cobalt. UV/visible spectroscopic analysis of the leached solu-tions indicated that the increased cobalt content in the solution was a result of flushing the acidified cobalt leaching solution with SO2. Fur-thermore, UV/visible spectroscopy confirmed that as SO2 was flushed into the acidified leaching solution, Co3＋ bearing minerals were re-duced to the readily soluble Co2＋ bearing minerals, and this resulted in the increase of total cobalt in the collected solution. The mechanism of the reduction of Co3＋ to Co2＋ bearing minerals when SO2 is flushed during the leaching of mixed Co-Cu oxidized ores, including the stability trends of Co3＋, Co2＋, and Cu2＋ complexes, as shown by their UV/visible spectra, are also discussed.
基金Financial supports from the NNSFCs (Grants 201276194 and 201306136)the Funds of Tianjin Key Laboratory of Marine Resources and Chemistry in TUST (Grants 201303 and 201206)the Natural Science Fund of TUST (Grant 20130112)
文摘It is well known that boron exists as polyborate anions in aqueous solution.Boron atom can coordinates to three or four oxygen atoms and borate can exist as not only the monomer but also the polymer.The polymerization
基金financial support from the National Natural Science Foundation of China (51274015)National Program on Key Basic Research Pr oject (973 Program) (2014CB846000)Test Fund of Peking University
文摘1 Introduction In recent years,the study has found that spherical graphite has a high charge and discharge capacity and electrochemical stability,is the ideal lithium battery anodematerial and important ultra-high capacitor material,with a high cost performance(Chuan et al,2012).Spherical
基金the National Natural Science Foundation of China (Grant No. 19704016).
文摘Several key problems involved in the analyses of spectra of asymmetric top molecules, i.e., the effective Hamiltonian, the representation and basis vector, identification of energy levels, the selection rules, the relative intensity, and Zeeman tuning rate, were elucidated systematically. Introducing the high-order centrifugal distortion terms into the effective Hamiltonian, the precision for calculation has been improved substantially, which allows us to analyze the high-lying rotational transitions. A global analysis of all available spectra of 14N16O2 in the ground vibronic state has been made to obtain a set of molecular constants of 14N16O2 in the ground vibronic state which is the most precise and extensive so far. Using the improved parameters, some FIR LMR lines left unassigned hitherto have been identified successfully.
基金supported by the National Natural Science Foundation of China(No.32370425).
文摘Phytochemical investigation of the branches of Viburnum awabuki K.Koch led to the isolation of thirteen known compounds,including five lignans(1-5),one phytosterol(6),two phenylpropanoids(7-8),one chromone derivative(9),three pentacyclic triterpenoids(10-12),and one glyceride(13).The structures of these compounds were elucidated through extensive spectroscopic analyses and comparison of experimental data with literature data.Additionally,the chemotaxonomic significance of the isolated secondary metabolites was also discussed.
基金supported by the National Water Pollution Control and Treatment Science and Technology Major Project of China(No.2017ZX07402002)
文摘A large amount of wastewater containing various toxic organic contaminants is produced during coal-to-liquids process. In this study, several spectroscopic methods were used to monitor the transformation of organic pollutants during an integrated chemical oxidation and biological process. The results showed that the hydrophobic acid fraction increased after Fenton oxidation, which was likely due to the production of small-molecule organic acids. Soluble microbial products were generated during biological treatment processes,which were degraded after ozonation; meanwhile, the hydrophilic base and acid components increased. Ultraviolet-visible spectroscopic analysis indicated that peaks at the absorption wavelengths of 280 and 254 nm, which are associated with aromatic substances, were detected in the raw water. The aromatic substances were gradually removed, becoming undetectable after biological aeration filter（BAF） treatment. Fourier transform infrared spectroscopy analysis revealed that the functional groups of phenols;benzene, toluene, ethylbenzene, and xylene（BTEX）; aromatic hydrocarbons; aliphatic acids;aldehydes; and esters were present in raw wastewater. The organic substances were oxidized into small molecules after Fenton treatment. Aromatic hydrocarbons were effectively removed through bioadsorption and biodegradation after BAF process.Biodegradable organic matter was reduced and finally became undetectable after anoxic–oxic treatment in combination with a membrane bioreactor. Four fluorescent components were fractionated and obtained via excitation–emission matrix parallel factor analysis（EEM-PARAFAC）. Dissolved organic matter fractionation in conjunction with EEM-PARAFAC was able to monitor more precisely the evolution of characteristic organic contaminants.
基金This work is financially supported by the National Wild Plant Germplasm Resources Infrastructure which is the follow-up work of a project called Standardization and Community for the Collection and Preservation of Important Wild Plant Germplasm Resources(2005DKA21006).
文摘Emblic medicine is a popular natural source in the world due to its outstanding healthcare and therapeutic functions.Our preliminary results indicated that the quality of emblic medicines might have an apparent regional variation.A rapid and effective geographical traceability system has not been designed yet.To trace the geographical origins so that their quality can be controlled,an integrated spectroscopic strategy including spectral pretreatment,outlier diagnosis,feature selection,data fusion,and machine learning algorithm was proposed.A featured data matrix(245220)was successfully generated,and a carefully adjusted RF machine learning algorithm was utilized to develop the geographical traceability model.The results demonstrate that the proposed strategy is effective and can be generalized.Sensitivity(SEN),specificity(SPE)and accuracy(ACC)of 97.65%,99.85%and 97.63%for the calibrated set,as well as 100.00%predictive efficiency,were obtained using this spectroscopic analysis strategy.Our study has created an integrated analysis process for multiple spectral data,which can achieve a rapid,nondestructive and green quality detection for emblic medicines originating from seventeen geographical origins.
文摘Near-infrared (NIR) spectroscopy was applied to reagent-free quantitative analysis of polysaccharide of a brand product of proprietary Chinese medicine (PCM) oral solution samples. A novel method, called absorbance upper optimization partial least squares (AUO-PLS), was proposed and successfully applied to the wavelength selection. Based on varied partitioning of the calibration and prediction sample sets, the parameter optimization was performed to achieve stability. On the basis of the AUO-PLS method, the selected upper bound of appropriate absorbance was 1.53 and the corresponding wavebands combination was 400 - 1880 & 2088 - 2346 nm. With the use of random validation samples excluded from the modeling process, the root-mean-square error and correlation coefficient of prediction for polysaccharide were 27.09 mg·L<sup>-</sup><sup>1</sup> and 0.888, respectively. The results indicate that the NIR prediction values are close to those of the measured values. NIR spectroscopy combined with AUO-PLS method provided a promising tool for quantification of the polysaccharide for PCM oral solution and this technique is rapid and simple when compared with conventional methods.
基金supported by the Science and Technology Project of Guangdong Province of China(Nos.2014A020213016 and 2014A020212445).
文摘The moving window bis corelation coefficients(MW BiCC)was proposed and employed for the discriminant analysis of transgenic sugarcane leaves and B-thalassemia with visible and near-infrared(Vis NIR)spectroscopy.The well-performed moving window principal component analysis linear discriminant analysis(MWPCA-LDA)was also conducted for comparison.A total of 306 transgenic(positive)and 150 nont ransgenic(negative)leave samples of sugarcane were collected and divided to calibration,prediction,and validation.The diffuse reflection spectra were corected using Savitzky-Golay(SG)smoothing with first-order derivative(d=1),third-degree polynomial(p=3)and 25 smpothing points(m=25).The selected waveband was 736-1054nm with MW-BiCC,and the positive and negative validation recognition rates(V_REC^(+),VREC^(-))were 100%,98.0%,which achieved the same effect as MWPCA-LDA.Another example,the 93 B-thalassemia(positive)and 148 nonthalassemia(negative)of human hemolytic samples were colloctod.The transmission spectra were corrected using SG smoothing withd=1,p=3 and m=53.Using M W-BiCC,many best wavebands were selected(e.g.,1116-1146,17941848 and 22842342nm).The V_REC^(+)and V_REC^(-)were both 100%,which achieved the same effect as MW-PCA-LDA.Importantly,the BICC only required ca lculating correlation cofficients between the spectrum of prediction sample and the average spectra of two types of calibration samples.Thus,BiCC was very simple in algorithm,and expected to obtain more applications.The results first confirmed the feasibility of distinguishing B-thalassemia and normal control samples by NIR spectroscopy,and provided a promising simple tool for large population thalassemia screening.
基金supported by the National Natural Science Foundation of China (GrantNos. 10873016,10633020,10603006,10803007,10903011,11003021 and 11073032)by the National Basic Research Program of China (973 Program Nos. 2007CB815403,2010CB833004 and 2009CB82480X)
文摘The Andromeda galaxy was observed by the Guoshoujing Telescope （formerly named the Large Sky Area Multi-Object Fiber Spectroscopic Telescope -- LAMOST）, during the 2009 commissioning phase. Due to the absence of standard stars for flux calibration, we use the photometric data of 15 intermediate bands in the Beijing-Arizona-Taipei-Connecticut （BATC） survey to calibrate the spectra. In to- tal, 59 spectra located in the bulge and disk of the galaxy are obtained. Kinematic and stellar population properties of the stellar content are derived with these spectra. We obtain the global velocity field and calculate corresponding rotation velocities out to about 7 kpc along the major axis. These rotation velocity measurements comple- ment those of the gas content, such as the H I and CO. The radial velocity dispersion shows that the stars in the bulge are more dynamically thermal and the disk is more rotationally-supported. The age distribution shows that the bulge was formed about 12 Gyr ago, the disk is relatively younger and the ages of some regions along the spi- ral arms can reach as young as about 1 Gyr. These young stellar populations have a relatively richer abundance and larger reddening. The overall average metallicity of the galaxy approximates the solar metallicity and a very weak abundance gradient is gained. The reddening map gives a picture of a dust-free bulge and a distinct dusty ring in the disk.
基金supported by National Natural Science Foundation of China(Nos.10975155,11175208,10990212)National Magnetic Confinement Fusion Science Program of China(Nos.2012GB101000,2011GB101000,2011GB107000,2009GB104003)
文摘The spectra of HeI（587.6 nm）,Hα（656.28 nm） and Dα（656.1 nm） of the helium discharges as well as the normal deuterium discharges have been measured with two optical spectroscopic multi-channel analysis（OMA） systems on the experimental advanced superconducting tokamak（EAST）.The influx ratio of the sum of H and D to He spectral lines and the influx ratio of H to D are given.In this way the ratio of hydrogen/deuterium ion（S/X B）H/D to（S/X B）He as well as（S/X B）H/D is not very sensitive to the variation in the edge density and temperature. The low-density helium discharges are operated in order to reduce the recycling hydrogen fluxes; however,the effect is not obvious.The possible reason is that the number of helium discharges is not enough and the content of hydrogen in the wall is still very abundant,which is caused by frequent wall conditionings and the vacuum leakage.The H/（H＋D） ratio decreases quickly after one lithium coating and reduces to less than 10%using several accumulated lithium wall conditioning.It is found that the deposited He atoms on the carbon wall will remain at a low level after several D2 discharges.
基金Supported by the National Natural Science Foundation of China
文摘The process of accurately defining and outlining mare basalt units is nec- essary for constraining the stratigraphy and ages of basalt units, which are used to determine the duration and the flux of lunar volcanism. We use a combination of Clementine＇s five-band ultraviolet/visible data and Ti02 and FeO abundance distri- bution maps to define homogenous mare basalt units and characterize their composi- tional variations （with maturity） in the Aristarchus region. With 20 groups of distinct mare basaltic soils identified using the method in this paper, six additional spectrally defined areas and five basaltic units are constructed, and their mineralogic quanfiza- tion values provide new constraints on their temporal and spatial evolution. Our results indicate that the Aristarchus region has diverse basalt units and a complex history of volcanic evolution. We also demonstrate that the techniques, from which spectrally distinct mare basalts can be mapped, performed well in this study and can be confi- dently expanded to other mare regions of the Moon.
基金National Natural Science Foundation of China(52161145409,21976116)SAFEA of China(“Belt and Road”Innovative Talent Exchange Foreign Expert Project#2023041004L)(High-end Foreign Expert Project#G2023041021L)Alexander-von-Humboldt Foundation of Germany(Group-Linkage Program)。
文摘The advances in transmission electron microscopy(TEM)have greatly improved the characterization of heterogeneous catalysts,offering valuable insights into their operational efficacy through the correlation of their physicochemical characteristics with performance,specificity,and robustness at nanoscales.Understanding tangible catalyst attributes and corresponding catalytic processes necessitates the identification and rationalization of catalyst behavior modifications during reaction conditions.Recent innovations in in-situ TEM techniques have opened new avenues to observe the progress of heterogeneous catalysis with unparalleled spatial precision,superior energy resolution,and precise temporal resolution in controlled or realistic catalytic environments.Herein,we have reviewed the established and evolving techniques for monitoring catalysts through the utilization of in-situ TEM.By combining in-situ TEM with cutting-edge spectroscopic methodologies like atomic electron tomography(AET),4D-STEM,cryogenic electron microscopy,and monochromated electron energy loss spectroscopy(EELS),a comprehensive approach to catalyst observation is achieved.Likewise,this advancement is expected to highlight and expand the crucial role of in-situ TEM in elucidating catalyst surface structures,active sites,and reaction pathways across key catalytic reactions,shaping the field of research in heterogeneous catalysis.Finally,the potential applications,advantages,and challenges of using in-situ TEM are emphasized and addressed in detail.
文摘Twenty-three progressive extractions were performed to study individual humic acids (HAs) and humin fractions from a typical black soil (Mollisol) in Heilongjiang Province, China using elemental analysis and spectroscopic techniques. After 23 HA extractions the residue was separated into high and low organic carbon humin fractions. HA yield was the highest for the first extraction and then gradually decreased with further extractions. Organic carbon (OC) of the humin fractions accounted for 58% of total OC …
基金supported by the National High Technology Research and Development Program of China (No.2006AA09Z243)the Natural Science Foundation of Shandong Province (No.Y2006A26)
文摘The laser induced breakdown spectroscopy(LIBS) is an element analysis technique with the advantages of real time detection,simultaneous multi-element identification,and in-situ and stand-off capacities.To evaluate its potential of ocean applications,in this paper,the time resolved laser-induced breakdown spectroscopy for calcium concentration detection in water is investigated.With the optimum experimental parameters,the plasma emission lifetime is determined to be about 500 ns with 532 nm laser excitation,and 1000 ns with 1064 nm laser excitation.The lowest detection concentration of 50 ppm is achieved for calcium detection in CaCl2 water solution using the 532 nm LIBS.Even better detection sensitivity is achieved using the 1064 nm LIBS,and the resulted lowest detection concentration of calcium is 25 ppm.The results suggest that it is feasible to develop LIBS as an on-line sensor for metal element monitoring in the sea.
基金supported by the Standardization Project Fund of Administration of Traditional Chinese Medicine(No.ZYBZH-Y-SD-32)the Specialized Fund for Dependent Innovation of Shandong Province(No.2013CXC20401)
文摘Three new secoiridoid glycosides,named lonijapoglycol A(1),aldosecolohanin C(2)and aldosecolohanin B(3),together with three known ones(4–6),have been isolated from the flower the buds of Lonicera japonica.All the structures were identified by spectroscopic analyses.Lonijapoglycol A(1)expressed significant anti-inflammatory activity to inhibit the release ofβ-glucuronidase induced by platelet-activating factor in rat polymorphonuclear leukocytes with an IC50 value of 3.76μmol·L^-1.
基金supported by the National Natural Science Foundation of China(Nos.21806064,U1730245,21906074,22176079)Fundamental Research Funds for the Central Universities(No.lzujbky-2021-sp27)。
文摘The radionuclide(RN)migration study is not only helpful to understand environmental behavior of RNs,but also can establish the basis for the safety assessment of geological disposal of high-level radioactive waste(HLW).In the context of China’s HLW disposal,this review briefly summaries the progress of China’s RN migration studies over the past decade regarding three aspects,RN sorption,RN transport and radioactive colloid.Domestic studies from other disciplines(such as geology and environmental science)are also included in this review because they can provide references for the RN migration study.Overall,China has achieved clear progress in RN migration study over the past decade,although large-scaled field experiments are lacked and a gap still exists comparing with the international advanced level.Finally,several suggestions are proposed for future RN migration research in China.
基金Supported by the National Natural Science Foundation of China
文摘Strongly Mg-enhanced stars with [Mg/Fe] 〉 1.0 show peculiar abundance patterns and hence are of great interest for our understanding of stellar formation and chemical evolution of the Galaxy. A systematic search for strongly Mg-enhanced stars based on low-resolution （R≈2000） spectra from the Sloan Digital Sky Survey （SDSS） is carried out by finding the synthetic spectrum that best matches the observed one in the region of Mg I b lines around λ5170 ,A via a profile matching method. The advantage of our method is that fitting parameters are refined by reproducing the [Mg/Fe] ratios of 47 stars from the very precise high-resolution spectroscopic （HRS） analysis by Nissen ＆ Schuster; and these parameters are crucial to the precision and validity of the derived Mg abundances. As a further check of our method, Mg abun- dances are estimated with our method for member stars in four Galactic globular clus- ters （M92, M 13, M3, M71） which cover the same metallicity range as our sample, and the results are in good agreement with those of HRS analysis in the literature. The val- idation of our method is also demonstrated by the agreement of [Mg/Fe] between our values and those of HRS analysis by Aoki et al. Finally, 33 candidates of strongly Mg- enhanced stars with [Mg/Fe]〉 1.0 are selected from 14 850 F and G stars. Follow-up observations will be carried out on these candidates with high-resolution spectroscopy by large telescopes in the near future, so as to check our selection procedure and to perform a precise and detailed abundance analysis and to explore the origins of these stars.
