In order to investigate the adsorption mechanism of trace metals to surficial sediments （SSs）, a selective extraction procedure was improved in the present work. The selective extraction procedure has been proved to...In order to investigate the adsorption mechanism of trace metals to surficial sediments （SSs）, a selective extraction procedure was improved in the present work. The selective extraction procedure has been proved to selectively remove and separate Fe, Mn oxides and organic materials （OMs） in the non-residual fraction from the SSs collected in Songhua River, China. After screening different kinds of conventional extractants of Fe and Mn oxides and OMs used for separation of heavy metals in the soils and sediments, NH2OH .HCl （0.1 mol/L） ＋ HNO3 （0.1 mol/L）, （NH4）2C2O4 （0.2 mol/L） ＋ H2C2O4 （pH 3.0）, and 30% of H2O2 were respectively applied to selectively extract Mn oxides, Fe/Mn oxides and OMs. After the extraction treatments, the target components were removed with extraction efficiencies between 86.09%--3.36% for the hydroxylamine hydrochloride treatment, 80.63%- 101.09% for the oxalate solution extraction, and 94.76%-102.83% for the hydrogen peroxide digestion, respectively. The results indicate that this selective extraction technology was effective for the extraction and separation ofFe, Mn oxides and OMs in the SSs, and important for further mechanism study of trace metal adsorption onto SSs.展开更多
In the extraction method for preparing KH2PO4, one of the key processes is the selective extraction of HCI over H3PO4. In our work, extraction kinetic studies have been carried out in a microfluidic device with a coax...In the extraction method for preparing KH2PO4, one of the key processes is the selective extraction of HCI over H3PO4. In our work, extraction kinetic studies have been carried out in a microfluidic device with a coaxial microchannel, using the extractant of 33.3% （by volume） trioctylamine （TOA） dissolved in n-octanol, with differ- ent aqueous phases： the HCI solution, the H3P04 solution, and H3PO4 and KCI solutions of different concentra- tions. The changes of the extraction efficiency of HC1 and H3P04 and the selectivity for HC1 along with the residence time were investigated. We found that fast extraction kinetics could be realized in microfluidic devices, and that HC1 could be extracted faster than H3P04 due to smaller mass transfer resistance and much stronger re- action between HCI and TOA. For the extraction of H3PO4 and KC1 solutions, the selectivity for HC1 first increased and then decreased when TOA was in excess of H3PO4 in the initial feeds, and in contrast, always increased when H3PO4 was in excess of TOA in the initial feeds. The diverse changes of selectivity for HCI along with the residence time indicate that a dynamic control of selectivity in microfluidic devices may be important and accessible for im- proving the KH2P04 conversion efficiency in extraction method.展开更多
An ammonia-based system was used to selectively leach cobalt(Co)from an African high-silicon low-grade Co ore,and the other elemental impurities were inhibited from leaching in this process.This process was simple and...An ammonia-based system was used to selectively leach cobalt(Co)from an African high-silicon low-grade Co ore,and the other elemental impurities were inhibited from leaching in this process.This process was simple and environmentally friendly.The results revealed that the leaching ratio of Co can reach up to 95.61%using(NH_(4))_(2)SO_(4)as a leaching agent under the following materials and conditions:(NH_(4))_(2)SO_(4)concentration 300 g/L,reductant dosage 0.7 g,leaching temperature 353 K,reaction time 4 h,and liquid-solid ratio 6 mL/g.The leaching kinetics of Co showed that the apparent activation energy of Co leaching was 76.07 kJ/mol(i.e.,in the range of 40-300 kJ/mol).This indicated that the leaching of Co from the Co ore was controlled by an interfacial chemical reaction,and then the developed leaching kinetics model of the Co can be expressed as 1-(1-α)^(1/3)=28.01×10~3×r_0^(-1)×C_((NH_(4))_(2)SO_(4))^(1.5)×exp(-76073/8.314 T)×t,whereαis the leaching ratio(%)of Co,r_0 is the average radius(m)of the Co ore particles,T is the temperature(K),and C_((NH_(4))_(2)SO_(4))is the initial reactant concentration(kg/m^(3)).展开更多
Fast development of nuclear power plants requires sustainable support of uranium for nuclear fuel.Uranium is the most critical radionuclide to prepare nuclear fuel.However,the extraction of low concentration of uraniu...Fast development of nuclear power plants requires sustainable support of uranium for nuclear fuel.Uranium is the most critical radionuclide to prepare nuclear fuel.However,the extraction of low concentration of uranium in uranium ore or complex systems needs highly efficient selective binding of uranium in the presence of other competing metal ions.The excellent oxidative capacity of excited*UO_(2)^(2+)active species makes uranyl-based materials high photocatalytic performance in phototransformation of organic chemicals into high valuable products under visible light irradiation.In this mini review,the selective preconcentration of uranium through photocatalytic and electrocatalytic strategies was mainly described.The application of uranyl-based materials in photocatalytic conversion and degradation of organic pollutants was summarized.This review reports the utilization of uranium from its first step(i.e.,extraction of uranium for nuclear fuel supply)to its last additional application(i.e.,uranyl-based materials as photocatalysts in transformation and conversion of organic pollutants for environmental pollution treatment)from the viewpoint of“turning uranium wastes into treasure,from waste recycling to reutilization.”In the end of this review,the challenges and perspectives of uranium separation and catalytic properties were described.展开更多
This study describes the development and validation of a sensitive and reliable method for determination of polybrominated diphenyl ethers（PBDEs）in atmospheric particulate matter using selective pressurized liquid e...This study describes the development and validation of a sensitive and reliable method for determination of polybrominated diphenyl ethers（PBDEs）in atmospheric particulate matter using selective pressurized liquid extraction（SPLE）and gas chromatography–mass spectrometry with a negative chemical ionization（GC-NCI-MS）.Extraction and clean-up were performed using PLE with 2 g florisil and 3 g silica placed in the extraction cells.Under optimal conditions,14 PBDEs were extracted at 70℃ using hexane/dichloromethane（50：50,v/v）as solvent.Validation of SPLE returned excellent recoveries for most analytes,with relative standard deviations mostly below20%.Method detection limits ranged from 0.13 to15.38 ng·mL^-1 for the GC-MS analyses.The method was successfully applied to atmospheric particulate matter of Beijing,where analytes were detected in the range of182.79 to 468.99 pg·m^-3.展开更多
In this paper, separation of Sr from associated elements （Na, K, Ca, Mg, and Ba） was carried out using an extraction chromatographic column packed with Sr selective specific resin consisting of an octanol solution o...In this paper, separation of Sr from associated elements （Na, K, Ca, Mg, and Ba） was carried out using an extraction chromatographic column packed with Sr selective specific resin consisting of an octanol solution of 4,4＇（5＇）-bis（t-butylcyclohexo）-lS-crown-6 sorbed on an inert polymeric support. Using 8.0 mol/L HNO3 as the eluent, Ba and associated elements were eluted immediately from the column, whereas Sr was strongly retained. The adsorbed Sr could then be stripped from the column as the eluent was changed to 0.05 mol/L HNO~. Complete Sr/Ba separation was demonstrated to be feasible in that Ba could be washed from the column leaving pure Sr by adequate rinsing with 8.0 mol/L HN03. Furthermore, matrix effect could be effectively eliminated and the selectivity of the method was improved. The method was applied for the determination of Sr in the high purity barium carbonate （BaCO3） product and seawater. The recoveries of Sr in 2 samples were determined to be 93.2% and 109%, respectively.展开更多
Strong mechanical vibration and acoustical signals of grinding process contain useful information related to load parameters in ball mills. It is a challenge to extract latent features and construct soft sensor model ...Strong mechanical vibration and acoustical signals of grinding process contain useful information related to load parameters in ball mills. It is a challenge to extract latent features and construct soft sensor model with high dimensional frequency spectra of these signals. This paper aims to develop a selective ensemble modeling approach based on nonlinear latent frequency spectral feature extraction for accurate measurement of material to ball volume ratio. Latent features are first extracted from different vibrations and acoustic spectral segments by kernel partial least squares. Algorithms of bootstrap and least squares support vector machines are employed to produce candidate sub-models using these latent features as inputs. Ensemble sub-models are selected based on genetic algorithm optimization toolbox. Partial least squares regression is used to combine these sub-models to eliminate collinearity among their prediction outputs. Results indicate that the proposed modeling approach has better prediction performance than previous ones.展开更多
Acid extraction methods have been used in the last half century to selectively extract the CO_(2)produced from different carbonate minerals in mixed samples.However,these methods are often time-consuming and labor int...Acid extraction methods have been used in the last half century to selectively extract the CO_(2)produced from different carbonate minerals in mixed samples.However,these methods are often time-consuming and labor intensive.Their application to clumped isotope(Δ47)analysis has not been demonstrated.We propose here an acid extraction method with phosphoric acid for bulk stable and clumped isotope analysis that treats mixtures of calcite and dolomite the same regardless of the proportional composition.CO_(2)evolved from calcite is extracted by allowing a reaction with phosphoric acid to proceed for 10 min at 50℃.We then extract CO_(2)evolved from dolomite by rapid ramping the acid temperature from 50 to 90℃and allowing the reaction to complete.The experimental results show that our method yields accurate calcite and dolomiteΔ_(47)values from mixed samples under different proportional compositions.Our method also displays equal or higher accuracy for calciteδ^(13)C and dolomiteδ^(13)C andδ^(18)O values from mixtures when compared to previous studies.Our approach exhibits higher sample throughput than previous methods,is adequate for clumped isotopic analysis and simplifies the reaction progression from over 24 h to less than 2 h,while maintaining relatively high isotopic obtaining accuracy.It yet poorly resolves calciteδ18O values,as found with previous methods.展开更多
As a typical bioflavonoid,diosmetin is desirable in the field of natural medicine,healthy food,and cosmetics by anti-cancer,antibacterial,antioxidant,estrogen-like and anti-inflammatory activities,and it comes from a ...As a typical bioflavonoid,diosmetin is desirable in the field of natural medicine,healthy food,and cosmetics by anti-cancer,antibacterial,antioxidant,estrogen-like and anti-inflammatory activities,and it comes from a wide range of sources in traditional Chinese medicine like spider fragrance,spearmint and chrysanthemum,as well as in Citrus fruit.However,traditional analytical methods such as silica gel column chromatography face multiple challenges in the selective extraction of diosmetin from biological materials and traditional Chinese medicinal materials.Therefore,it is urgent to develop a new type of absorbent with high efficiency,recyclability and good specificity to diosmetin.In this investigation,a magnetic surface molecularly imprinted polymer(labeled as Diosmetin/SMIPs)was synthesized employing magnetic nanoparticles as the carrier and 4-vinylpyridinyl(4-VP)as the functional monomer by surface imprinting technology.The functional monomer was screened by the binding energy(△E)between functional monomers and template molecules via computational simulation.The Diosmetin/SMIPs had a high level of specific recognition and adsorption capability towards diosmetin with a 20.25 mg g^(-1) adsorption capacity and an imprinting factor(IF)of 2.28.Additionally,it demonstrated excellent regeneration performance with 8 adsorption/desorption cycles.In addition,91.20%-94.16% of spiked diosmetin was recovered from the lemon peel samples.The strategy of constructing Diosmetin/SMIPs based on computational simulation can effectively enhance the specific adsorption performance of diosmetin.Meanwhile,Diosmetin/SMIPs synthesized by imprinting polymerization showed excellent anti-interference and reusability,and realized efficient targeted extraction of diosmetin from lemon peel samples.The results of this investigation provide a promising adsorbent for selective enrichment of diosmetin from Citrus fruit and complicated materials.展开更多
D2EHPA(P204),tri-butyl-phosphate(TBP)and sodium chloride(NaCl)were attractive for selective extraction of scandium from acid leaching solution of red mud.The extraction parameters of P204 concentration(X_(P204)),NaCl ...D2EHPA(P204),tri-butyl-phosphate(TBP)and sodium chloride(NaCl)were attractive for selective extraction of scandium from acid leaching solution of red mud.The extraction parameters of P204 concentration(X_(P204)),NaCl concentration(C_(NaCl)),pH value,reaction time,stirring speed and O/A were investigated to extract scandium and separate iron from the acid leaching solution.The extraction mechanism was analyzed by Fourier transform infrared spectroscopy(FT-IR)and thermodynamic theory.The single-stage extraction efficiency of scandium,iron andβ(Sc/Fe)were 99.1%,9.4%and 1061.2,respectively,with C_(NaCl) of 75 g/L and XP204 of 0.75 at solution pH value of 1.2 and stirring speed of 200 r/min for 6 min,in which a good separation effect of scandium and iron was obtained.The vibration absorption peak Sc─O was contributed to the extraction of scandium with P204.The complex[FeCln]^(3−n) existed in the solution with adding NaCl into the acid leaching solution.The value of n was higher and the valence state of the complex[FeCln]^(3−n) was lower with an increase of chloride concentration,which restricts the extraction efficiency of iron with P204.The extraction of three stages in the counter-current simulation experiments was carried out according to the McCabe-Thiele diagram.Gibbs free energy change(ΔG)of−5.93 kJ/mol,enthalpy change(ΔH)of 23.45 kJ/mol and entropy change(ΔH)of 98.54 J/(mol·K)were obtained in the solvent extraction proces,which indicate that the extraction reaction is easily spontaneous and endothermic and a proper increase of temperature is conducive to the extraction of scandium.展开更多
In order to obtain better carbonation effect, extraction behavior of slag batch is necessary to study. Relevant parameters like selective extraction yield were originally discussed. The relationship between selective ...In order to obtain better carbonation effect, extraction behavior of slag batch is necessary to study. Relevant parameters like selective extraction yield were originally discussed. The relationship between selective extraction yield and conversion ratio was systemically focused on. The results show that alkaline earth metal conversion ratio is changed with leaching time and NH4CI concentration by first order exponential, and the maximum conversion for calcium keeps about 68% at 120 min in 0.4 mol/L NH4C1 solution, while leaching temperature and particle size have a linear effect on conversion ratio. Selective extraction yield of calcium is more than 93%, and the value of Mg is less than 5%. Apparent layer bands of silicon and calcium appear in the surface area through morphology detection of slag after leaching, and the case for 38-75 μm slag batch is more obvious than 75 150 μm slag and slag with larger particle size when leaching in 0.4 mol/L NH4Cl solution for 90 rain at 60 ℃.展开更多
Four types of undisturbed soil in Ain Oussera region around the Es-Salam reactor facility,located in the south of Algiers, Algeria, at about 200 km, were artificially contaminated for one year with stable CsCl and SrC...Four types of undisturbed soil in Ain Oussera region around the Es-Salam reactor facility,located in the south of Algiers, Algeria, at about 200 km, were artificially contaminated for one year with stable CsCl and SrCl2 in order to simulate an accidental release of these elements. This study was performed using sequential extraction procedure based on Shultz method and containing six fractions. The selectivity of the extraction protocol was confirmed by analyzing some elements（Ca, C, Fe, Mn, Si and Al） designed as indicators of the targeted phases. The obtained results showed an acceptable reproducibility, in view of the coefficients of variation that were in most cases less than 15%. The results revealed a clear proportional correlation between the extracted Cs and Sr in fractions for each soil and some of soils physicochemical properties. Organic matter appears to play an important role in the soil retention, particularly for Cs where the extracted percentage exceeds to 30% in whole soils. In contrast, strontium expresses a remarkable affinity for the fraction bound to carbonates. The obtained data also indicate that the availability of Cs in the four soils is less important compared to Sr availability. This is illustrated by the higher value of extracted Sr in the easily extractible phase, including the water-soluble and the exchangeable fraction.展开更多
Andrographolide is the main active ingredient of Andrographis paniculata(Burm.f.)Nees,known as“natural antibiotic”.Here,for the purpose of discovering a more efficient,low-cost extraction and separation method,the r...Andrographolide is the main active ingredient of Andrographis paniculata(Burm.f.)Nees,known as“natural antibiotic”.Here,for the purpose of discovering a more efficient,low-cost extraction and separation method,the research status of andrographolide was reviewed.At present,researches only take extraction rate as the only index to optimize extraction parameters,but ignores the importance of extraction selectivity.It is usually meaningless to blindly pursue the extraction rate without considering the difficulty and cost of subsequent separation.So,factors affecting extraction selectivity such as solvent choice,temperature and physicochemical effects caused by extraction technique itself,are first discussed.Different extraction techniques for andrographolide were discussed by comparing the selectivity,efficiency and cost of extraction.The separation procedures of andrographolide such as decolorization,impurity removal,crystallization,membrane separation,solid-phase extraction and partition chromatography and their challenges and possible strategies are also discussed.It is hoped that this review can provide guidance for researchers who are committed to advancing the field of andrographolide extraction and purification.展开更多
Liquid-solid phase separation of permalloy in liquid Mg results in selectively dissolved Ni,which provides a unique opportunity for the design of immiscible heterogeneous composite materials and the comprehensive meta...Liquid-solid phase separation of permalloy in liquid Mg results in selectively dissolved Ni,which provides a unique opportunity for the design of immiscible heterogeneous composite materials and the comprehensive metal recycling of permalloy scraps.A guideline of the alloy design for the liquid-solid phase separation system was proposed.The effects of immersion temperature and time on the Ni extraction were studied by an experimental method.The diffusion behavior of Ni from the permalloy to liquid Mg and the microstructure evolution in the permalloy during the liquid-solid phase separation were discussed.The results show that the Ni in the permalloy was quickly extracted into the liquid Mg and formed an Mg-Ni alloy,while the other components such as Fe,Co,and Mn were held back in the phase-separated permalloy.The phase-separated permalloy with the solidified Mg exhibits a three-dimensional(3D)Fe/Mg bicontinuous composite structure.Furthermore,simple treatments were carried out for the reaction products such as the Fe/Mg bicontinuous composite and the Mg-Ni alloy,and the recycling strategies for functionalization of these treated reaction products were provided.A 3D porous Fe-based alloy with electromagnetic interference(EMI)shielding efficiency of 52 dB can be obtained if Mg is removed from the Fe/Mg bicontinuous composite.Instead of the complete separation of pure Ni from the recycled Mg-Ni alloy by vacuum distilling,the Mg-Ni alloy can be enriched into Mg2 Ni as an initial hydrogen storage material.展开更多
A method of quantification of perfluorinated compounds(PFCs)from atmospheric particulate matter(APM)is described.A single step pretreatment method,selective pressurized liquid extraction(SPLE),was developed to reduce ...A method of quantification of perfluorinated compounds(PFCs)from atmospheric particulate matter(APM)is described.A single step pretreatment method,selective pressurized liquid extraction(SPLE),was developed to reduce the high matrix background and avoid contamination from commonly used multiple sample pretreatment steps.An effective sorbent was selected to purify the PFCs during SPLE,followed by liquid chromatography-tandem mass spectrometry(LC–MS/MS),for quantification of PFCs.Conditions affecting the SPLE efficiency,including temperature,static extraction time,and number of extraction cycles used,were studied.The optimum conditions were found to be 120℃,10 min,and 3 cycles,respectively.LC-MS/MS method was developed to obtain the optimal sensitivity specific to PFCs.The method detection limits(MDLs)were 0.006 to 0.48 ng/g for the PFCs studied and the linear response range was from 0.1 to 100 ng/g.To ensure accurate values were obtained,each step of the experiment was evaluated and controlled to prevent contamination.The optimized method was tested by performing spiking experiments in natural particulate matter matrices and good rates of recovery and reproducibility were obtained for all target compounds.Finally,the method was successfully used to measure 16 PFCs in the APM samples collected in Beijing over five years from 2015 to 2019.It is observed that some PFCs follow the trend of total PFC changes,and can be attributed to the environment influencing events and policy enforcement,while others don't seem to change as much with time of the year or from year to year.展开更多
Extraction of uranium from radioactive waste-water is of significant importance for environmental protection and the recovery of uranium resource.Different from the previous reports to use the solid absorbent/photocat...Extraction of uranium from radioactive waste-water is of significant importance for environmental protection and the recovery of uranium resource.Different from the previous reports to use the solid absorbent/photocatalyst for U(VI)removal,herein,we proposed a new eco-friendly method for the rapid and selective extraction of uranium from aqueous solutions under visible light without solid materials.At optimal pH value and in the presence of organics like alcohols,the U(VI)could be extracted efficiently to form brown uranium solid over wide uranium concentrations under anaerobic condition and visible light,by utilizing the excitation of the given U(VI)species.With comprehensive modelling of the electronic ultraviolet-visible(UV-Vis)properties,it is proved that pH adjusting towards U(VI)could induce efficient ligand-to-metal-charge-transfer(LMCT)within the uranyl complex under visible light and the reduction of U(VI)to form U(V),which can be transformed into U(IV)via disproportionation reaction.The resulting U(IV)in solid phase makes the extraction much more convenient in operation.More importantly,the excellent selectivity for uranium extraction over interfering alkali metal ions,transition metal ions and the lanthanide metal ions shows a powerful application potential.展开更多
In light of the increasing demand for environmental protection and energy conservation,the recovery of highly valuable metals,such as Li,Co,and Ni,from spent lithium-ion batteries(LIBs)has attracted widespread attenti...In light of the increasing demand for environmental protection and energy conservation,the recovery of highly valuable metals,such as Li,Co,and Ni,from spent lithium-ion batteries(LIBs)has attracted widespread attention.Most conventional recycling strategies,however,suffer from a lack of lithium recycling,although they display high efficiency in the recovery of Co and Ni.In this work,we report an efficient extraction process of lithium from the spent LIBs by using a functional imidazolium ionic liquid.The extraction efficiency can be reached to 92.5%after a three-stage extraction,while the extraction efficiency of Ni-Co-Mn is less than 4.0%.The new process shows a high selectivity of lithium ion.FTIR spectroscopy and ultraviolet are utilized to characterize the variations in the functional groups during extraction to reveal that the possible extraction mechanism is cation exchange.The results of this work provide an effective and sustainable strategy of lithium recycling from spent LIBs.展开更多
The dynamics of Cd scavenging from solutions by Fe/Mn oxides in natural surface coatings （NSCs） was investigated under laboratory conditions. Selective extraction methods were employed to estimate the contributions ...The dynamics of Cd scavenging from solutions by Fe/Mn oxides in natural surface coatings （NSCs） was investigated under laboratory conditions. Selective extraction methods were employed to estimate the contributions of Fe/Mn oxides, where hydroxylamine hydrochloride （0.01 mol/L NH2OH-HCl ＋ 0.01 mol/L HNO3）, sodium dithionite （0.4 mol/L Na2S2O4） and nitric acid （10% HNO3） were used as extraction reagents. The Cd scavenging was accomplished with developing periods of the NSCs （totally 21 data sets）. The resulting process dynamics fitted well to the Elovich equation, demonstrating that the amount of Cd scavenged was proportional to the increments of Fe/Mn oxides that were accumulated in the NSCs. The amount of Cd bound to Fe oxides （MCdFe） and Mn oxides （MCdMn） could be quantified by solving two equations based on the properties of two extraction reagents. The amount of Cd scavenged by Fe/Mn oxides could also be estimated using MCdFe and MCdMn divided by the total amounts of Fe and Mn oxides in the NSCs, respectively. The results indicated that the Cd scavenging by Fe/Mn oxides was dominated by Fe oxides, with less roles attributed to Mn oxides. The estimated levels of Cd scavenging through Fe and Mn oxides agreed well with those predicted through additive-adsorption and linear-regression models.展开更多
Now LiCoO2 is the most widely used electrode material in commercial rechargeable lithium-based batteries; however, the toxicity of cobalt and the scarcity of cobalt sources, as well as the limited charge/discharge cap...Now LiCoO2 is the most widely used electrode material in commercial rechargeable lithium-based batteries; however, the toxicity of cobalt and the scarcity of cobalt sources, as well as the limited charge/discharge capacity（130-140 mA.h.g-1） of LiCoO2 electrode drive many efforts to develop various alternative electrode materials, including diverse transition metal oxides and their lithiated counterparts. Amongst them, iron oxides,展开更多
Day by day,biometric-based systems play a vital role in our daily lives.This paper proposed an intelligent assistant intended to identify emotions via voice message.A biometric system has been developed to detect huma...Day by day,biometric-based systems play a vital role in our daily lives.This paper proposed an intelligent assistant intended to identify emotions via voice message.A biometric system has been developed to detect human emotions based on voice recognition and control a few electronic peripherals for alert actions.This proposed smart assistant aims to provide a support to the people through buzzer and light emitting diodes(LED)alert signals and it also keep track of the places like households,hospitals and remote areas,etc.The proposed approach is able to detect seven emotions:worry,surprise,neutral,sadness,happiness,hate and love.The key elements for the implementation of speech emotion recognition are voice processing,and once the emotion is recognized,the machine interface automatically detects the actions by buzzer and LED.The proposed system is trained and tested on various benchmark datasets,i.e.,Ryerson Audio-Visual Database of Emotional Speech and Song(RAVDESS)database,Acoustic-Phonetic Continuous Speech Corpus(TIMIT)database,Emotional Speech database(Emo-DB)database and evaluated based on various parameters,i.e.,accuracy,error rate,and time.While comparing with existing technologies,the proposed algorithm gave a better error rate and less time.Error rate and time is decreased by 19.79%,5.13 s.for the RAVDEES dataset,15.77%,0.01 s for the Emo-DB dataset and 14.88%,3.62 for the TIMIT database.The proposed model shows better accuracy of 81.02%for the RAVDEES dataset,84.23%for the TIMIT dataset and 85.12%for the Emo-DB dataset compared to Gaussian Mixture Modeling(GMM)and Support Vector Machine(SVM)Model.展开更多
基金The National Basic Research Program (973) of China (No. 2004CB3418501)
文摘In order to investigate the adsorption mechanism of trace metals to surficial sediments （SSs）, a selective extraction procedure was improved in the present work. The selective extraction procedure has been proved to selectively remove and separate Fe, Mn oxides and organic materials （OMs） in the non-residual fraction from the SSs collected in Songhua River, China. After screening different kinds of conventional extractants of Fe and Mn oxides and OMs used for separation of heavy metals in the soils and sediments, NH2OH .HCl （0.1 mol/L） ＋ HNO3 （0.1 mol/L）, （NH4）2C2O4 （0.2 mol/L） ＋ H2C2O4 （pH 3.0）, and 30% of H2O2 were respectively applied to selectively extract Mn oxides, Fe/Mn oxides and OMs. After the extraction treatments, the target components were removed with extraction efficiencies between 86.09%--3.36% for the hydroxylamine hydrochloride treatment, 80.63%- 101.09% for the oxalate solution extraction, and 94.76%-102.83% for the hydrogen peroxide digestion, respectively. The results indicate that this selective extraction technology was effective for the extraction and separation ofFe, Mn oxides and OMs in the SSs, and important for further mechanism study of trace metal adsorption onto SSs.
基金Supported by the National Natural Science Foundation of China(91334201)
文摘In the extraction method for preparing KH2PO4, one of the key processes is the selective extraction of HCI over H3PO4. In our work, extraction kinetic studies have been carried out in a microfluidic device with a coaxial microchannel, using the extractant of 33.3% （by volume） trioctylamine （TOA） dissolved in n-octanol, with differ- ent aqueous phases： the HCI solution, the H3P04 solution, and H3PO4 and KCI solutions of different concentra- tions. The changes of the extraction efficiency of HC1 and H3P04 and the selectivity for HC1 along with the residence time were investigated. We found that fast extraction kinetics could be realized in microfluidic devices, and that HC1 could be extracted faster than H3P04 due to smaller mass transfer resistance and much stronger re- action between HCI and TOA. For the extraction of H3PO4 and KC1 solutions, the selectivity for HC1 first increased and then decreased when TOA was in excess of H3PO4 in the initial feeds, and in contrast, always increased when H3PO4 was in excess of TOA in the initial feeds. The diverse changes of selectivity for HCI along with the residence time indicate that a dynamic control of selectivity in microfluidic devices may be important and accessible for im- proving the KH2P04 conversion efficiency in extraction method.
基金financially supported by the National Nature Science Foundation of China(Nos.51804136,52064021,51974140,and 52064018)the Key Projects of Jiangxi Key R&D Plan,China(No.20192ACB70017)+3 种基金the Jiangxi Provincial Cultivation Program for Academic and Technical Leaders of Major Subjects,China(No.20204 BCJL23031)the Jiangxi Province Science Fund for Distinguished Young Scholars,China(No.20202ACB213002)the Program of Qingjiang Excellent Young Talents,Jiangxi University of Science and Technology,China(JXUSTQJBJ 2020004)the Distinguished Professor Program of Jinggang Scholars in institutions of higher learning,Jiangxi Province,China。
文摘An ammonia-based system was used to selectively leach cobalt(Co)from an African high-silicon low-grade Co ore,and the other elemental impurities were inhibited from leaching in this process.This process was simple and environmentally friendly.The results revealed that the leaching ratio of Co can reach up to 95.61%using(NH_(4))_(2)SO_(4)as a leaching agent under the following materials and conditions:(NH_(4))_(2)SO_(4)concentration 300 g/L,reductant dosage 0.7 g,leaching temperature 353 K,reaction time 4 h,and liquid-solid ratio 6 mL/g.The leaching kinetics of Co showed that the apparent activation energy of Co leaching was 76.07 kJ/mol(i.e.,in the range of 40-300 kJ/mol).This indicated that the leaching of Co from the Co ore was controlled by an interfacial chemical reaction,and then the developed leaching kinetics model of the Co can be expressed as 1-(1-α)^(1/3)=28.01×10~3×r_0^(-1)×C_((NH_(4))_(2)SO_(4))^(1.5)×exp(-76073/8.314 T)×t,whereαis the leaching ratio(%)of Co,r_0 is the average radius(m)of the Co ore particles,T is the temperature(K),and C_((NH_(4))_(2)SO_(4))is the initial reactant concentration(kg/m^(3)).
基金support from the National Natural Science Foundation of China(Nos.U24B20195,U23A20105,U2341289,22341602,22327807)was acknowledged.
文摘Fast development of nuclear power plants requires sustainable support of uranium for nuclear fuel.Uranium is the most critical radionuclide to prepare nuclear fuel.However,the extraction of low concentration of uranium in uranium ore or complex systems needs highly efficient selective binding of uranium in the presence of other competing metal ions.The excellent oxidative capacity of excited*UO_(2)^(2+)active species makes uranyl-based materials high photocatalytic performance in phototransformation of organic chemicals into high valuable products under visible light irradiation.In this mini review,the selective preconcentration of uranium through photocatalytic and electrocatalytic strategies was mainly described.The application of uranyl-based materials in photocatalytic conversion and degradation of organic pollutants was summarized.This review reports the utilization of uranium from its first step(i.e.,extraction of uranium for nuclear fuel supply)to its last additional application(i.e.,uranyl-based materials as photocatalysts in transformation and conversion of organic pollutants for environmental pollution treatment)from the viewpoint of“turning uranium wastes into treasure,from waste recycling to reutilization.”In the end of this review,the challenges and perspectives of uranium separation and catalytic properties were described.
基金supported by the National Natural Science Foundation of China(41325010)
文摘This study describes the development and validation of a sensitive and reliable method for determination of polybrominated diphenyl ethers（PBDEs）in atmospheric particulate matter using selective pressurized liquid extraction（SPLE）and gas chromatography–mass spectrometry with a negative chemical ionization（GC-NCI-MS）.Extraction and clean-up were performed using PLE with 2 g florisil and 3 g silica placed in the extraction cells.Under optimal conditions,14 PBDEs were extracted at 70℃ using hexane/dichloromethane（50：50,v/v）as solvent.Validation of SPLE returned excellent recoveries for most analytes,with relative standard deviations mostly below20%.Method detection limits ranged from 0.13 to15.38 ng·mL^-1 for the GC-MS analyses.The method was successfully applied to atmospheric particulate matter of Beijing,where analytes were detected in the range of182.79 to 468.99 pg·m^-3.
基金supported by Public Welfare Scientific Research Project of the Ministry of Land and Resource of China(Nos.200911044 and 201111028)the Fund of Key Laboratory of Global Change and Marine-Atmospheric Chemistry, State Oceanic Administration(No.GCMAC1206)
文摘In this paper, separation of Sr from associated elements （Na, K, Ca, Mg, and Ba） was carried out using an extraction chromatographic column packed with Sr selective specific resin consisting of an octanol solution of 4,4＇（5＇）-bis（t-butylcyclohexo）-lS-crown-6 sorbed on an inert polymeric support. Using 8.0 mol/L HNO3 as the eluent, Ba and associated elements were eluted immediately from the column, whereas Sr was strongly retained. The adsorbed Sr could then be stripped from the column as the eluent was changed to 0.05 mol/L HNO~. Complete Sr/Ba separation was demonstrated to be feasible in that Ba could be washed from the column leaving pure Sr by adequate rinsing with 8.0 mol/L HN03. Furthermore, matrix effect could be effectively eliminated and the selectivity of the method was improved. The method was applied for the determination of Sr in the high purity barium carbonate （BaCO3） product and seawater. The recoveries of Sr in 2 samples were determined to be 93.2% and 109%, respectively.
基金Supported partially by the Post Doctoral Natural Science Foundation of China(2013M532118,2015T81082)the National Natural Science Foundation of China(61573364,61273177,61503066)+2 种基金the State Key Laboratory of Synthetical Automation for Process Industriesthe National High Technology Research and Development Program of China(2015AA043802)the Scientific Research Fund of Liaoning Provincial Education Department(L2013272)
文摘Strong mechanical vibration and acoustical signals of grinding process contain useful information related to load parameters in ball mills. It is a challenge to extract latent features and construct soft sensor model with high dimensional frequency spectra of these signals. This paper aims to develop a selective ensemble modeling approach based on nonlinear latent frequency spectral feature extraction for accurate measurement of material to ball volume ratio. Latent features are first extracted from different vibrations and acoustic spectral segments by kernel partial least squares. Algorithms of bootstrap and least squares support vector machines are employed to produce candidate sub-models using these latent features as inputs. Ensemble sub-models are selected based on genetic algorithm optimization toolbox. Partial least squares regression is used to combine these sub-models to eliminate collinearity among their prediction outputs. Results indicate that the proposed modeling approach has better prediction performance than previous ones.
基金funded by the fellowship of the China Postdoctoral Science Foundation(No.2020M682134)the National Natural Science Foundation of China(Nos.41872149,42076220)the Shandong Postdoctoral Innovation Research Project。
文摘Acid extraction methods have been used in the last half century to selectively extract the CO_(2)produced from different carbonate minerals in mixed samples.However,these methods are often time-consuming and labor intensive.Their application to clumped isotope(Δ47)analysis has not been demonstrated.We propose here an acid extraction method with phosphoric acid for bulk stable and clumped isotope analysis that treats mixtures of calcite and dolomite the same regardless of the proportional composition.CO_(2)evolved from calcite is extracted by allowing a reaction with phosphoric acid to proceed for 10 min at 50℃.We then extract CO_(2)evolved from dolomite by rapid ramping the acid temperature from 50 to 90℃and allowing the reaction to complete.The experimental results show that our method yields accurate calcite and dolomiteΔ_(47)values from mixed samples under different proportional compositions.Our method also displays equal or higher accuracy for calciteδ^(13)C and dolomiteδ^(13)C andδ^(18)O values from mixtures when compared to previous studies.Our approach exhibits higher sample throughput than previous methods,is adequate for clumped isotopic analysis and simplifies the reaction progression from over 24 h to less than 2 h,while maintaining relatively high isotopic obtaining accuracy.It yet poorly resolves calciteδ18O values,as found with previous methods.
基金supported by the National Natural Science Foundation of China(Nos.32301259,32101228,32271527 and 32371536)the“Pioneer”and“Leading Goose”R&D Program of Zhejiang(Nos.2022C02023 and 2023C02015)+1 种基金the Research Foundation of Talented Scholars of Zhejiang A&F University(No.2021LFR058)the Dean-ship of Scientific Research at Northern Border University,Arar,KSA for funding this research work through the project number“NBU-FPEJ-2024-177-01”.
文摘As a typical bioflavonoid,diosmetin is desirable in the field of natural medicine,healthy food,and cosmetics by anti-cancer,antibacterial,antioxidant,estrogen-like and anti-inflammatory activities,and it comes from a wide range of sources in traditional Chinese medicine like spider fragrance,spearmint and chrysanthemum,as well as in Citrus fruit.However,traditional analytical methods such as silica gel column chromatography face multiple challenges in the selective extraction of diosmetin from biological materials and traditional Chinese medicinal materials.Therefore,it is urgent to develop a new type of absorbent with high efficiency,recyclability and good specificity to diosmetin.In this investigation,a magnetic surface molecularly imprinted polymer(labeled as Diosmetin/SMIPs)was synthesized employing magnetic nanoparticles as the carrier and 4-vinylpyridinyl(4-VP)as the functional monomer by surface imprinting technology.The functional monomer was screened by the binding energy(△E)between functional monomers and template molecules via computational simulation.The Diosmetin/SMIPs had a high level of specific recognition and adsorption capability towards diosmetin with a 20.25 mg g^(-1) adsorption capacity and an imprinting factor(IF)of 2.28.Additionally,it demonstrated excellent regeneration performance with 8 adsorption/desorption cycles.In addition,91.20%-94.16% of spiked diosmetin was recovered from the lemon peel samples.The strategy of constructing Diosmetin/SMIPs based on computational simulation can effectively enhance the specific adsorption performance of diosmetin.Meanwhile,Diosmetin/SMIPs synthesized by imprinting polymerization showed excellent anti-interference and reusability,and realized efficient targeted extraction of diosmetin from lemon peel samples.The results of this investigation provide a promising adsorbent for selective enrichment of diosmetin from Citrus fruit and complicated materials.
基金Projects(51904097,51804103)supported by the National Natural Science Foundation of ChinaProject(2019GGJS056)supported by the Training Program for Young Backbone Teachers in Colleges and Universities of Henan Province,China+2 种基金Project(HB201905)supported by Open Foundation of State Environmental Protection Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution Control,ChinaProject(202102310548)supported by Scientific and Technological Project of Henan Province,ChinaProject(21IRTSTHN006)supported by Program for Innovative Research Team in the University of Henan Province,China。
文摘D2EHPA(P204),tri-butyl-phosphate(TBP)and sodium chloride(NaCl)were attractive for selective extraction of scandium from acid leaching solution of red mud.The extraction parameters of P204 concentration(X_(P204)),NaCl concentration(C_(NaCl)),pH value,reaction time,stirring speed and O/A were investigated to extract scandium and separate iron from the acid leaching solution.The extraction mechanism was analyzed by Fourier transform infrared spectroscopy(FT-IR)and thermodynamic theory.The single-stage extraction efficiency of scandium,iron andβ(Sc/Fe)were 99.1%,9.4%and 1061.2,respectively,with C_(NaCl) of 75 g/L and XP204 of 0.75 at solution pH value of 1.2 and stirring speed of 200 r/min for 6 min,in which a good separation effect of scandium and iron was obtained.The vibration absorption peak Sc─O was contributed to the extraction of scandium with P204.The complex[FeCln]^(3−n) existed in the solution with adding NaCl into the acid leaching solution.The value of n was higher and the valence state of the complex[FeCln]^(3−n) was lower with an increase of chloride concentration,which restricts the extraction efficiency of iron with P204.The extraction of three stages in the counter-current simulation experiments was carried out according to the McCabe-Thiele diagram.Gibbs free energy change(ΔG)of−5.93 kJ/mol,enthalpy change(ΔH)of 23.45 kJ/mol and entropy change(ΔH)of 98.54 J/(mol·K)were obtained in the solvent extraction proces,which indicate that the extraction reaction is easily spontaneous and endothermic and a proper increase of temperature is conducive to the extraction of scandium.
基金Project(2006BAE03A07)supported by National Key Technology Research and Development Program of 11th Five-year Plan of China
文摘In order to obtain better carbonation effect, extraction behavior of slag batch is necessary to study. Relevant parameters like selective extraction yield were originally discussed. The relationship between selective extraction yield and conversion ratio was systemically focused on. The results show that alkaline earth metal conversion ratio is changed with leaching time and NH4CI concentration by first order exponential, and the maximum conversion for calcium keeps about 68% at 120 min in 0.4 mol/L NH4C1 solution, while leaching temperature and particle size have a linear effect on conversion ratio. Selective extraction yield of calcium is more than 93%, and the value of Mg is less than 5%. Apparent layer bands of silicon and calcium appear in the surface area through morphology detection of slag after leaching, and the case for 38-75 μm slag batch is more obvious than 75 150 μm slag and slag with larger particle size when leaching in 0.4 mol/L NH4Cl solution for 90 rain at 60 ℃.
基金part of an internal project in Birine Nuclear Research Center(CRNB)and was supported by funding from the Algerian Atomic Energy Commission
文摘Four types of undisturbed soil in Ain Oussera region around the Es-Salam reactor facility,located in the south of Algiers, Algeria, at about 200 km, were artificially contaminated for one year with stable CsCl and SrCl2 in order to simulate an accidental release of these elements. This study was performed using sequential extraction procedure based on Shultz method and containing six fractions. The selectivity of the extraction protocol was confirmed by analyzing some elements（Ca, C, Fe, Mn, Si and Al） designed as indicators of the targeted phases. The obtained results showed an acceptable reproducibility, in view of the coefficients of variation that were in most cases less than 15%. The results revealed a clear proportional correlation between the extracted Cs and Sr in fractions for each soil and some of soils physicochemical properties. Organic matter appears to play an important role in the soil retention, particularly for Cs where the extracted percentage exceeds to 30% in whole soils. In contrast, strontium expresses a remarkable affinity for the fraction bound to carbonates. The obtained data also indicate that the availability of Cs in the four soils is less important compared to Sr availability. This is illustrated by the higher value of extracted Sr in the easily extractible phase, including the water-soluble and the exchangeable fraction.
基金the National Natural Science Foundation of China(No.81872956)。
文摘Andrographolide is the main active ingredient of Andrographis paniculata(Burm.f.)Nees,known as“natural antibiotic”.Here,for the purpose of discovering a more efficient,low-cost extraction and separation method,the research status of andrographolide was reviewed.At present,researches only take extraction rate as the only index to optimize extraction parameters,but ignores the importance of extraction selectivity.It is usually meaningless to blindly pursue the extraction rate without considering the difficulty and cost of subsequent separation.So,factors affecting extraction selectivity such as solvent choice,temperature and physicochemical effects caused by extraction technique itself,are first discussed.Different extraction techniques for andrographolide were discussed by comparing the selectivity,efficiency and cost of extraction.The separation procedures of andrographolide such as decolorization,impurity removal,crystallization,membrane separation,solid-phase extraction and partition chromatography and their challenges and possible strategies are also discussed.It is hoped that this review can provide guidance for researchers who are committed to advancing the field of andrographolide extraction and purification.
基金supported by the Space Application System of China Manned Space Program(No.KJZ-YY-NCL06)the National Natural Science Foundation of China(Nos.51974288,52174280)+1 种基金the Scientific Instrument Developing Project of the Chinese Academy of Sciences(No.YJKYYQ20210012)the IMR Innovation Fund(No.E255A901).
文摘Liquid-solid phase separation of permalloy in liquid Mg results in selectively dissolved Ni,which provides a unique opportunity for the design of immiscible heterogeneous composite materials and the comprehensive metal recycling of permalloy scraps.A guideline of the alloy design for the liquid-solid phase separation system was proposed.The effects of immersion temperature and time on the Ni extraction were studied by an experimental method.The diffusion behavior of Ni from the permalloy to liquid Mg and the microstructure evolution in the permalloy during the liquid-solid phase separation were discussed.The results show that the Ni in the permalloy was quickly extracted into the liquid Mg and formed an Mg-Ni alloy,while the other components such as Fe,Co,and Mn were held back in the phase-separated permalloy.The phase-separated permalloy with the solidified Mg exhibits a three-dimensional(3D)Fe/Mg bicontinuous composite structure.Furthermore,simple treatments were carried out for the reaction products such as the Fe/Mg bicontinuous composite and the Mg-Ni alloy,and the recycling strategies for functionalization of these treated reaction products were provided.A 3D porous Fe-based alloy with electromagnetic interference(EMI)shielding efficiency of 52 dB can be obtained if Mg is removed from the Fe/Mg bicontinuous composite.Instead of the complete separation of pure Ni from the recycled Mg-Ni alloy by vacuum distilling,the Mg-Ni alloy can be enriched into Mg2 Ni as an initial hydrogen storage material.
基金supported by the NQI Project of National key R&D Program of China (No.2016YFF0201102)the project for the“Development of analytical method and certified reference materials for tracing air pollutant source” (No.21AKY1514)from the National Institute of Metrology,Beijing,China。
文摘A method of quantification of perfluorinated compounds(PFCs)from atmospheric particulate matter(APM)is described.A single step pretreatment method,selective pressurized liquid extraction(SPLE),was developed to reduce the high matrix background and avoid contamination from commonly used multiple sample pretreatment steps.An effective sorbent was selected to purify the PFCs during SPLE,followed by liquid chromatography-tandem mass spectrometry(LC–MS/MS),for quantification of PFCs.Conditions affecting the SPLE efficiency,including temperature,static extraction time,and number of extraction cycles used,were studied.The optimum conditions were found to be 120℃,10 min,and 3 cycles,respectively.LC-MS/MS method was developed to obtain the optimal sensitivity specific to PFCs.The method detection limits(MDLs)were 0.006 to 0.48 ng/g for the PFCs studied and the linear response range was from 0.1 to 100 ng/g.To ensure accurate values were obtained,each step of the experiment was evaluated and controlled to prevent contamination.The optimized method was tested by performing spiking experiments in natural particulate matter matrices and good rates of recovery and reproducibility were obtained for all target compounds.Finally,the method was successfully used to measure 16 PFCs in the APM samples collected in Beijing over five years from 2015 to 2019.It is observed that some PFCs follow the trend of total PFC changes,and can be attributed to the environment influencing events and policy enforcement,while others don't seem to change as much with time of the year or from year to year.
基金This work was supported by the National Natural Science Foundation of China(21976054,21976014,U1930402)the National Key Research and Development Program of China(2017YFA0207002)+1 种基金the Science Challenge Project(TZ2016004)the Fundamental Research Funds for the Central Universities(2020MS036).
文摘Extraction of uranium from radioactive waste-water is of significant importance for environmental protection and the recovery of uranium resource.Different from the previous reports to use the solid absorbent/photocatalyst for U(VI)removal,herein,we proposed a new eco-friendly method for the rapid and selective extraction of uranium from aqueous solutions under visible light without solid materials.At optimal pH value and in the presence of organics like alcohols,the U(VI)could be extracted efficiently to form brown uranium solid over wide uranium concentrations under anaerobic condition and visible light,by utilizing the excitation of the given U(VI)species.With comprehensive modelling of the electronic ultraviolet-visible(UV-Vis)properties,it is proved that pH adjusting towards U(VI)could induce efficient ligand-to-metal-charge-transfer(LMCT)within the uranyl complex under visible light and the reduction of U(VI)to form U(V),which can be transformed into U(IV)via disproportionation reaction.The resulting U(IV)in solid phase makes the extraction much more convenient in operation.More importantly,the excellent selectivity for uranium extraction over interfering alkali metal ions,transition metal ions and the lanthanide metal ions shows a powerful application potential.
基金supported by the Science Fund for Major Program of National Natural Science Foundation of China(21890762)Innovation Academy for Green Manufacture,Chinese Academy of Sciences(IAGM-2020-C28).
文摘In light of the increasing demand for environmental protection and energy conservation,the recovery of highly valuable metals,such as Li,Co,and Ni,from spent lithium-ion batteries(LIBs)has attracted widespread attention.Most conventional recycling strategies,however,suffer from a lack of lithium recycling,although they display high efficiency in the recovery of Co and Ni.In this work,we report an efficient extraction process of lithium from the spent LIBs by using a functional imidazolium ionic liquid.The extraction efficiency can be reached to 92.5%after a three-stage extraction,while the extraction efficiency of Ni-Co-Mn is less than 4.0%.The new process shows a high selectivity of lithium ion.FTIR spectroscopy and ultraviolet are utilized to characterize the variations in the functional groups during extraction to reveal that the possible extraction mechanism is cation exchange.The results of this work provide an effective and sustainable strategy of lithium recycling from spent LIBs.
基金The National Basic Research Program (973) of China (No. 2004CB3418501)
文摘The dynamics of Cd scavenging from solutions by Fe/Mn oxides in natural surface coatings （NSCs） was investigated under laboratory conditions. Selective extraction methods were employed to estimate the contributions of Fe/Mn oxides, where hydroxylamine hydrochloride （0.01 mol/L NH2OH-HCl ＋ 0.01 mol/L HNO3）, sodium dithionite （0.4 mol/L Na2S2O4） and nitric acid （10% HNO3） were used as extraction reagents. The Cd scavenging was accomplished with developing periods of the NSCs （totally 21 data sets）. The resulting process dynamics fitted well to the Elovich equation, demonstrating that the amount of Cd scavenged was proportional to the increments of Fe/Mn oxides that were accumulated in the NSCs. The amount of Cd bound to Fe oxides （MCdFe） and Mn oxides （MCdMn） could be quantified by solving two equations based on the properties of two extraction reagents. The amount of Cd scavenged by Fe/Mn oxides could also be estimated using MCdFe and MCdMn divided by the total amounts of Fe and Mn oxides in the NSCs, respectively. The results indicated that the Cd scavenging by Fe/Mn oxides was dominated by Fe oxides, with less roles attributed to Mn oxides. The estimated levels of Cd scavenging through Fe and Mn oxides agreed well with those predicted through additive-adsorption and linear-regression models.
基金the National Natural Science Foundation of China(Nos.20401015 and 50574082)Beijing Nova Pro-gram(No.2005B20)Program for New Century Excellent Talents in Universities of China
文摘Now LiCoO2 is the most widely used electrode material in commercial rechargeable lithium-based batteries; however, the toxicity of cobalt and the scarcity of cobalt sources, as well as the limited charge/discharge capacity（130-140 mA.h.g-1） of LiCoO2 electrode drive many efforts to develop various alternative electrode materials, including diverse transition metal oxides and their lithiated counterparts. Amongst them, iron oxides,
基金Deanship of Scientific Research at Majmaah University for supporting this work under Project No.R-2022-166.
文摘Day by day,biometric-based systems play a vital role in our daily lives.This paper proposed an intelligent assistant intended to identify emotions via voice message.A biometric system has been developed to detect human emotions based on voice recognition and control a few electronic peripherals for alert actions.This proposed smart assistant aims to provide a support to the people through buzzer and light emitting diodes(LED)alert signals and it also keep track of the places like households,hospitals and remote areas,etc.The proposed approach is able to detect seven emotions:worry,surprise,neutral,sadness,happiness,hate and love.The key elements for the implementation of speech emotion recognition are voice processing,and once the emotion is recognized,the machine interface automatically detects the actions by buzzer and LED.The proposed system is trained and tested on various benchmark datasets,i.e.,Ryerson Audio-Visual Database of Emotional Speech and Song(RAVDESS)database,Acoustic-Phonetic Continuous Speech Corpus(TIMIT)database,Emotional Speech database(Emo-DB)database and evaluated based on various parameters,i.e.,accuracy,error rate,and time.While comparing with existing technologies,the proposed algorithm gave a better error rate and less time.Error rate and time is decreased by 19.79%,5.13 s.for the RAVDEES dataset,15.77%,0.01 s for the Emo-DB dataset and 14.88%,3.62 for the TIMIT database.The proposed model shows better accuracy of 81.02%for the RAVDEES dataset,84.23%for the TIMIT dataset and 85.12%for the Emo-DB dataset compared to Gaussian Mixture Modeling(GMM)and Support Vector Machine(SVM)Model.
