This study explores the controllable synthesis of CuAlO_(2) using copper hydroxide and pseudo-boehmite powders as raw materials via a simple solid-phase ball milling method,along with its catalytic performance investi...This study explores the controllable synthesis of CuAlO_(2) using copper hydroxide and pseudo-boehmite powders as raw materials via a simple solid-phase ball milling method,along with its catalytic performance investigation in methanol steam reforming(MSR).Various catalysts were prepared under different conditions,such as calcination temperature,calcination atmosphere,and heating rate.Characterization techniques including BET,XRD,XPS,SEM and H2-TPR were employed to analyze the samples.The results revealed significant effects of calcination temperature on the phase compositions,specific surface area,reduction performance,and surface properties of the CA-T catalysts.Based on the findings,a synthesis route of CuAlO_(2) via the solid-phase method was proposed,highlighting the importance of high calcination temperature,nitrogen atmosphere,and low heating rate for CuAlO_(2) formation.Catalytic evaluation data demonstrated that CuAlO_(2) could catalyze MSR without pre-reduction,with the catalytic performance of CA-T catalysts being notably influenced by calcination temperature.Among the prepared catalysts,the CA-1100 catalyst exhibited the highest catalytic activity and stability.The findings of this study might be useful for the further study of the catalytic material for sustained release catalysis,including the synthesis of catalytic materials and the regulation of sustained release catalytic performance.展开更多
Biapenem, a new parenteral carbapenem, has been widely used for treating bacterial infections. A simple, effective and accurate method based on solid-phase extraction （SPE） and HPLC was developed for the quantitativ...Biapenem, a new parenteral carbapenem, has been widely used for treating bacterial infections. A simple, effective and accurate method based on solid-phase extraction （SPE） and HPLC was developed for the quantitative determination of biapenem in human plasma. Stability and feasibility of the method was validated through a series of experiments. Using Vitamin B6 as an internal standard, analyte was separated on a Capcell Pak C18 column after SPE on Oasis hydrophilic-lipophilic balance （HLB） cartridge. The mobile phase was comprised of 0.05 mol/L NaH2PO4 （pH 5.7） and methanol （98：2, v/v） at a flow rate of 1.0 mL/min. Ultraviolet absorbance was measured at 300 nm. The calibration curve was linear in the concentration range of 0.04-50.00 μg/mL, and the lower limit of quantification was as low as 0.04 μg/mL. Recovery rates of biapenem at 0.10, 5.00, and 25.00 μg/mL were about 70%. The validated method has been successfully applied for quantifying biapenem in human samples and a pharmacokinetic study of 12 healthy volunteers who received three different doses （150, 300 and 600 mg） of biapenem by intravenous infusion. Our method has featured good accuracy and precision, and the processed sample was stable. Therefore, it can be propagated for clinical use.展开更多
The new catalytic kinetic spectrophotometric method for Au（III） determination was developed and validated. It was based on the catalytic effect of gold on the oxidation of sudan red III by ammonium peroxodisulfate ...The new catalytic kinetic spectrophotometric method for Au（III） determination was developed and validated. It was based on the catalytic effect of gold on the oxidation of sudan red III by ammonium peroxodisulfate （（NH4）2S2O8） with nitrilo triacetic acid as an activator in microemulsion and H2SO4 medium. Under optimum conditions, there was the linearity of the calibration curve in the concentration range from 0 to 20 μg/L Au（Ⅲ） at 520 nm. The relative standard deviation was 3.0% with a correlation coefficient of 0.9986. The detection limit achieved was 9.75 × 10^-5 μg/mL. A new method using a column packed with sulfhydryl dextrose gel （SDG） as a solid-phase extractant has been developed for the preconcentration and separation of Au（Ⅲ） ions. The method has been applied to the determination of trace gold with satisfactory results.展开更多
TMSOTf-catalyzed intramolecular seleno-arylation of tethered alkenes was performed using polystyrene-supported succini- midyl selenide as the selenium source. This catalytic process provides an efficient method for th...TMSOTf-catalyzed intramolecular seleno-arylation of tethered alkenes was performed using polystyrene-supported succini- midyl selenide as the selenium source. This catalytic process provides an efficient method for the regioselective synthesis of dihydrocoumarins possessing a seleno-functionality, followed by traceless cleavage of selenium linker to provide dihydrocoumar- ins and coumarins in good yields and purifies.展开更多
Chlorinated paraffins（SCCPs） are widely used worldwide, and they can be released into the environment during their production, transport, usage and disposal, which pose potential risks for human health. In this work...Chlorinated paraffins（SCCPs） are widely used worldwide, and they can be released into the environment during their production, transport, usage and disposal, which pose potential risks for human health. In this work, an efficient, reliable and rapid pretreatment method based on matrix solid-phase dispersion（MSPD） was developed for the analysis of short-chain CPs（SCCPs） in human placenta by gas chromatograph-electron capture negative ion low-resolution mass spectrometry（GC-ECNI-LRMS） and gas chromatography–quadrupole time-of-flight mass spectrometry（GC–QTOF-HRMS）. The MSPD-relevant parameters including dispersing sorbent,sample-to-sorbent mass ratio, and elution solvent were optimized using the orthogonal test.Silica gel was found to be the optimal dispersing sorbent among the selected matrices. Under the optimal conditions, 44% acidic silica gel can be used as the co-sorbent to remove lipid and eluted by the mixture of hexane and dichloromethane（7：3, V/V）. The spiked recoveries of the optimized method were 77.4% and 91.4% for analyzing SCCPs in human placenta by GC-ECNI-LRMS and GC–QTOF-HRMS, and the corresponding relative standard deviations were10.2% and 5.6%, respectively. The method detection limit for the total SCCPs was 36.8 ng/g（dry weight, dw） and 19.2 ng/g（dw） as measured by GC-ECNI-LRMS and GC–QTOF-HRMS,respectively. The concentrations of SCCPs in four human placentas were in the range of展开更多
A new multi-residue method based on solid-phase extraction (SPE) with centrifugation was developed for determination and quantitation of 67 pesticides in water samples. Two SPE cartridges were tested: Chromabond C18 a...A new multi-residue method based on solid-phase extraction (SPE) with centrifugation was developed for determination and quantitation of 67 pesticides in water samples. Two SPE cartridges were tested: Chromabond C18 and Oasis HLB. Parameters that influence the extraction efficiency such as the eluent volume, the sample loading volume, the addition of organic solvent to water sample, sorbent drying and elute concentration were optimized. The innovation of this work was the examination of the use of a centrifugation technique in both the drying and elution steps. When combined with centrifugation, the volume of the elution solvent was reduced to 2 mL and the time for sorbent drying decreased also to 10 min under vacuum. Under the optimized conditions, this method showed good recoveries higher than 65% - 68% for the 67 analyzed pesticides using the C18 and HLB cartridges with relative standard deviations lower than 9.7% - 12.3%. Limits of quantification were between 2 and 20 ng.L–1. The simplicity of the described method, use of less of organic solvent, short procedure time, and good recoveries demonstrate the advantages of this environmentally friendly approach for routine analysis of numerous samples.展开更多
Improved analytical methods for the metabolomic profiling of tissue samples are constantly needed.Currently,conventional sample preparation methods often involve tissue biopsy and/or homogenization,which disrupts the ...Improved analytical methods for the metabolomic profiling of tissue samples are constantly needed.Currently,conventional sample preparation methods often involve tissue biopsy and/or homogenization,which disrupts the endogenous metabolome.In this study,solid-phase microextraction(SPME)fibers were used to monitor changes in endogenous compounds in homogenized and intact ovine lung tissue.Following SPME,a Biocrates AbsoluteIDQ assay was applied to make a downstream targeted metabolomics analysis and confirm the advantages of in vivo SPME metabolomics.The AbsoluteIDQ kit enabled the targeted analysis of over 100 metabolites via solid-liquid extraction and SPME.Statistical analysis revealed significant differences between conventional liquid extractions from homogenized tissue and SPME results for both homogenized and intact tissue samples.In addition,principal component analysis revealed separated clustering among all the three sample groups,indicating changes in the metabolome due to tissue homogenization and the chosen sample preparation method.Furthermore,clear differences in free metabolites were observed when extractions were performed on the intact and homogenized tissue using identical SPME procedures.Specifically,a direct comparison showed that 47 statistically distinct metabolites were detected between the homogenized and intact lung tissue samples(P<0.05)using mixed-mode SPME fibers.These changes were probably due to the disruptive homogenization of the tissue.This study's findings highlight both the importance of sample preparation in tissue-based metabolomics studies and SPME's unique ability to perform minimally invasive extractions without tissue biopsy or homogenization while providing broad metabolite coverage.展开更多
In the present work,a new transient calculation method for parameters that can be used to evaluate the ability of oxygen control in a non-isothermal lead-bismuth eutectic(LBE)loop with solid-phase oxygen control was p...In the present work,a new transient calculation method for parameters that can be used to evaluate the ability of oxygen control in a non-isothermal lead-bismuth eutectic(LBE)loop with solid-phase oxygen control was proposed.It incorporates the dissolution process of PbO particles and the oxygen mass transfer process,and an optimized method was used for finding out the optimized oxygen mass transfer coefficient.In numerical terms,three mass transfer models were simultaneously applied,and comparisons of calculated and experimental results from the CRAFT loop indicated that the optimized calculation method and these new oxygen mass transfer models were correct and applicable to other LBE loops.Through this calculation method,we aimed to optimize prediction of the distribution of oxygen and iron concentrations,time taken to establish the steady state of oxygen,and maximum dissolution/precipitation rates of corrosion products and corrosion depth across the entire LBE loop.We hope that this work will provide a potential reference for designing a more intelligent oxygen control system in the future.展开更多
The enrichment of chromium in the magnetic iron chromite(Fe(Cr_(x)Fe_(1-x))_(2)O_(4))phase is crucial for the recovery and recycling of chromium in stainless-steel pickling sludge.The kinetics and reaction mechanism o...The enrichment of chromium in the magnetic iron chromite(Fe(Cr_(x)Fe_(1-x))_(2)O_(4))phase is crucial for the recovery and recycling of chromium in stainless-steel pickling sludge.The kinetics and reaction mechanism of the solid-phase reaction between Fe_(3)O_(4)and Cr_(2)O_(3)were investigated using the diffusion couple method at 1473 K.Not only the diffusion behavior of Fe^(2+)ions and Cr^(3+)ions was elucidated,but also the solid solution behavior of Fe^(3+)ions was discussed clearly.The microscopic morphology of the diffusion couple and the change in the concentrations of Fe and Cr cations across the diffusion layers were analyzed using scanning electron microscopy and en-ergy dispersive spectroscopy.The self-diffusion coefficients of cations were calculated based on the concentration profiles of Fe and Cr,with the results indicating that the self-diffusion coefficient of the Fe ions was consistently higher than that of the Cr ions.Additionally,a mixture of Fe_(3)O_(4)and Cr_(2)O_(3)was annealed at 1373-1473 K for 1-5 h,and the kinetic parameters were calculated by studying the phase content of the product.The phase content of Fe(Cr_(x)Fe_(1-x))_(2)O_(4)in the product was determined by Rietveld refinement of X-ray diffraction data,revealing that an activation energy(E)of 177.20 kJ·mol^(-1) and a pre-exponential factor(B)of 610.78 min^(-1)of the solid-phase reac-tion that produced the Fe(Cr_(x)Fe_(1-x))_(2)O_(4)spinel.展开更多
By combining the strong and light carbon fibers （CFs） with polymers, composite materials with extraordinary mechanical properties are achieved. However, the mechanical properties of the as-prepared CF-reinforced pol...By combining the strong and light carbon fibers （CFs） with polymers, composite materials with extraordinary mechanical properties are achieved. However, the mechanical properties of the as-prepared CF-reinforced polymer composites can not satisfy the applications in certain fields, especially for the poor interactions between CFs and the polymers. To enhance the mechanical properties of composite materials, a solid phase grafting method has been developed to improve the adhesion forces between CFs and the polymer, by modifying the surfaces of CFs. The effects of the reaction temperature, reaction time, as well as the dosage of the initiator and maleic anhydride （MAH） on the grafting efficiency have been investigated systematically. The structure and the surface chemistry of functionalized CFs have been characterized by Fourier Transform Infrared （FT-IR）, Scanning Electron Microscope （SEM）, X-ray Photoelectron Spectroscopy （XPS）, Thermogravimetric （TG）, and contact angle test. All of these results demonstrate that MAH is grafted onto the surface of CFs successfully by the solid phase grafting method. The MAH grafted CFs significantly improve its wettability, which further improves the interfacial adhesion between CFs and the polymeric matrix. The optimal reaction conditions are determined, such as the MAH/CF molar ratio, the dosage of initiator, the reaction temperature and the reaction time to be 3/1, 2%, 90℃ and 4 h, respectively. These attractive interracial characteristics of modified CFs suggest that the method proposed herein is a novel and efficient approach to develop CF-reinforced polymer composites with outstanding mechanical properties for cutting-edge industrial applications.展开更多
Rice flour, puparium of yellow mealworm, peanut shell and sunflower seed shell are made into the culture medium, and the optimal solid-phase fermen- tation formula for M. flavoviride is figured out. In the solid-phase...Rice flour, puparium of yellow mealworm, peanut shell and sunflower seed shell are made into the culture medium, and the optimal solid-phase fermen- tation formula for M. flavoviride is figured out. In the solid-phase fermentation, Design-Expert is applied to analyze the significance of all components on the sporu- lotion, and response surface method used to optimize the fermentation medium of M. flavoviride. The results show that puparlum of yellow mealworm is the most sig- nificant component for the sporulation; and the optimal medium formula for the fermentation of M. flavoviride： 0.25-g rice flour, 0. 14-g yellow mealworm pupari- urn, 1.00-g peanut shell, and 0.25-g sunflower seedshell. In this optimal medium, the sporulation achieves 100. 013 × 10^8 spores/mL fungal liquid, 31.7% higher than that of the initial design. Application of the optimal formula will reduce the production cost, obtain higher yield of spores, produce no pollution, and offer tech- nical support for the future large-scale production.展开更多
In this paper,we consider the maximal positive definite solution of the nonlinear matrix equation.By using the idea of Algorithm 2.1 in ZHANG(2013),a new inversion-free method with a stepsize parameter is proposed to ...In this paper,we consider the maximal positive definite solution of the nonlinear matrix equation.By using the idea of Algorithm 2.1 in ZHANG(2013),a new inversion-free method with a stepsize parameter is proposed to obtain the maximal positive definite solution of nonlinear matrix equation X+A^(*)X|^(-α)A=Q with the case 0<α≤1.Based on this method,a new iterative algorithm is developed,and its convergence proof is given.Finally,two numerical examples are provided to show the effectiveness of the proposed method.展开更多
Convex feasibility problems are widely used in image reconstruction,sparse signal recovery,and other areas.This paper is devoted to considering a class of convex feasibility problem arising from sparse signal recovery...Convex feasibility problems are widely used in image reconstruction,sparse signal recovery,and other areas.This paper is devoted to considering a class of convex feasibility problem arising from sparse signal recovery.We rst derive the projection formulas for a vector onto the feasible sets.The centralized circumcentered-reection method is designed to solve the convex feasibility problem.Some numerical experiments demonstrate the feasibility and e ectiveness of the proposed algorithm,showing superior performance compared to conventional alternating projection methods.展开更多
Marine thin plates are susceptible to welding deformation owing to their low structural stiffness.Therefore,the efficient and accurate prediction of welding deformation is essential for improving welding quality.The t...Marine thin plates are susceptible to welding deformation owing to their low structural stiffness.Therefore,the efficient and accurate prediction of welding deformation is essential for improving welding quality.The traditional thermal elastic-plastic finite element method(TEP-FEM)can accurately predict welding deformation.However,its efficiency is low because of the complex nonlinear transient computation,making it difficult to meet the needs of rapid engineering evaluation.To address this challenge,this study proposes an efficient prediction method for welding deformation in marine thin plate butt welds.This method is based on the coupled temperature gradient-thermal strain method(TG-TSM)that integrates inherent strain theory with a shell element finite element model.The proposed method first extracts the distribution pattern and characteristic value of welding-induced inherent strain through TEP-FEM analysis.This strain is then converted into the equivalent thermal load applied to the shell element model for rapid computation.The proposed method-particularly,the gradual temperature gradient-thermal strain method(GTG-TSM)-achieved improved computational efficiency and consistent precision.Furthermore,the proposed method required much less computation time than the traditional TEP-FEM.Thus,this study lays the foundation for future prediction of welding deformation in more complex marine thin plates.展开更多
A procedure of low temperature solid-phase sintering（LTSS） was carried out to fabricate sintered metal fibrous media（SMFM） with high specific surface area.Stainless steel fibers which were produced by cutting proc...A procedure of low temperature solid-phase sintering（LTSS） was carried out to fabricate sintered metal fibrous media（SMFM） with high specific surface area.Stainless steel fibers which were produced by cutting process were first plated with a coarse copper coating layer by electroless plating process.A low-temperature sintering process was then completed at about 800 °C for 1 h under the protection of hydrogen atmosphere.The results show that a novel SMFM with complex surface morphology and high specific surface area（0.2 m2/g） can be obtained in this way.The effect of sintering temperature on the surface morphology and specific surface area of SMFM was studied by means of scanning electron microscopy and Brunauer-Emmett-Teller.The damage of micro-structure during the sintering process mainly contributed to the loss of specific surface area of SMFM and the optimal sintering temperature was 800 °C.展开更多
A solid-phase sintering process for the low-cost fabrication of composite micro-channels was developed. Three kinds of composite micro-channels with metallic porous structures were designed. The sintering process was ...A solid-phase sintering process for the low-cost fabrication of composite micro-channels was developed. Three kinds of composite micro-channels with metallic porous structures were designed. The sintering process was studied and optimized to obtain porous-structured micro-channels with high porosity. The flow resistance and heat transfer performance in the composite micro-channels were investigated. The composite micro-channels show acceptable flow resistance, significant enhancement of heat transfer and dramatic improvement of flow boiling stability, which indicates a promising prospect for the application in forced convective heat transfer.展开更多
A new method for simultaneous determination of four phthalate esters （ PAEs） in commercial fat-containing foods was developed by the combination of a packed nanofibers column based on solid-phase extraction with gas...A new method for simultaneous determination of four phthalate esters （ PAEs） in commercial fat-containing foods was developed by the combination of a packed nanofibers column based on solid-phase extraction with gas chromatography-flame ionization detector （ GC-FID ）. Conditions for obtaining optimum extraction efficiency such as extraction solvents, morphologies of adsorbent, ion strength and pH were investigated and optimized in detail. Under the optimized conditions, the limits of detection （LODs） found for dibutyl phthalate （DBP） , butyl benzyl phthalate （BBP）, diethyl hexyl phthalate （DEHP） and di-n-octyl phthalate （DNOP） were 50, 25, 50 and 25 ng/g, respectively. Good linearity of four PAEs was achieved in the range of 50 to 4 000 ng/g. The proposed method was applied for analyzing different kinds of fat-containing samples. PAEs in commercial fat-containing samples can be highly extracted by a packed solid-phase extraction column of 5 mg polystyrene （ PS） nanofibers. The satisfactory average recoveries were obtained in the range of 96. 7% to 102. 3% , and the relative standard deviations （RSDs） below 5% were achieved. The proposed method reduces the organic solvent consumption, the complex and tedious procedures for sample pretreatment, and achieves high sensitivity and reproducibility for the investigated PAEs.展开更多
A new chemiluminescence flow system has been developed for sequential determina-tion of benzoic acid based on the reaction of the compound with copper carbonate entrapped in a solid-phase reactor. It was found that t...A new chemiluminescence flow system has been developed for sequential determina-tion of benzoic acid based on the reaction of the compound with copper carbonate entrapped in a solid-phase reactor. It was found that the unsaturated complex of Cu(II) and benzoic acid (1:1) has strong catalytic effect on the luminol-H2O2 chemiluminescence reaction. The calibration graph is linear over the range of 0.025 ~ 60 g/mL of benzoic acid, with a relative standard deviation of less than 3.0 %, and the detection limit is 0.01礸穖L-1. The proposed method was applied to the determination of benzoic acid content in different pharmaceutical formulations.展开更多
A new pre-column derivation HPLC method with solid-phase extraction to determine captopril in human plasma was established. Derivation products were extracted by a solid-phase extraction method after the reagent, p-a-...A new pre-column derivation HPLC method with solid-phase extraction to determine captopril in human plasma was established. Derivation products were extracted by a solid-phase extraction method after the reagent, p-a-dibromoacetophenone(p-BPB), was added in the plasma samples. The samples were analyzed in a VP-ODS column with UV-detector. The calibration curve of captopril was linear within the range of 5~1000 ngmL-1 with r=0.9987, the recovery of this method was 98.652.04%, within day and between day RSD were no more than 3.4% and 8.4% respectively. To study the pharmacokinetics and the relative bioavailability of captopril tablets, two formulations of captopril tablets were given to 18 healthy male volunteers according to a randomized 2-way cross-over design with a 1-week washout period. The respective AUC0~6 , Cmax and Tmax values of the two formulations were 424.5125.7 and 439.4113.3 mghL-1; 505.9244.6 and 504.8172.2 mgL-1; 0.6620.181 and 0.5280.176 h. Results from statistics analysis showed that there were no significant difference between the AUC0~6 , Cmax and Tmax values of the two formulations, The relative bioavailability of tablets I with respect to II was 96.114.6% from AUC0~6 measurement. Bioequivalance was observed between the two tablets.展开更多
Chitosan was prepared with stressing method by blending chitin and solid alkali in a single-screw extruder at given temperature and characterized by potentiometric titration,gel permeation chromatography(GPC),infrared...Chitosan was prepared with stressing method by blending chitin and solid alkali in a single-screw extruder at given temperature and characterized by potentiometric titration,gel permeation chromatography(GPC),infrared spectrum(IR)and carbon-13 magnetic resonance sperctroscopy(^(13)C NMR).Chitosan with a deacetylation degree(DD)of 76.1%was obtained at a mass ratio 0.2∶1∶1 for H_2 O/chitin/NaOH at 160℃for 12 min.Compared to conventional solution method(usually 1∶10 for chitin/NaOH),the alkali assumption greatly decreased.Molecular weight of chitosan obtained by solid-phase method(S3,M_w1.54×10^(5))was lower than that obtained by suspension method(Y2,M_w3.34×10^(5)).During deacetylation,molecular weight decreased with high reaction temperature and long reaction time but remained same at different initial ratios of NaOH/chitin.It might be concluded that degradation of chitosan was caused by breakout of the main chain of the oxidized chitosan catalyzed by alkali during the deactylation.IR and^(13)C NMR showed that structures of chitosans prepared by solid-phase method were not changed.展开更多
基金supported by the Scientific Research Foundation for High-level Talents of Anhui University of Science and Technology(2023yjrc51)the National Natural Science Foundation of China(22172184)+2 种基金the Foundation of State Key Laboratory of Coal Conversion(J24-25-603)the Fundamental Research Project of ICC-CAS(SCJC-DT-2023-01)Weiqiao-UCAS Special Projects on Low-Carbon Technology Development(GYY-DTFZ-2022-015)。
文摘This study explores the controllable synthesis of CuAlO_(2) using copper hydroxide and pseudo-boehmite powders as raw materials via a simple solid-phase ball milling method,along with its catalytic performance investigation in methanol steam reforming(MSR).Various catalysts were prepared under different conditions,such as calcination temperature,calcination atmosphere,and heating rate.Characterization techniques including BET,XRD,XPS,SEM and H2-TPR were employed to analyze the samples.The results revealed significant effects of calcination temperature on the phase compositions,specific surface area,reduction performance,and surface properties of the CA-T catalysts.Based on the findings,a synthesis route of CuAlO_(2) via the solid-phase method was proposed,highlighting the importance of high calcination temperature,nitrogen atmosphere,and low heating rate for CuAlO_(2) formation.Catalytic evaluation data demonstrated that CuAlO_(2) could catalyze MSR without pre-reduction,with the catalytic performance of CA-T catalysts being notably influenced by calcination temperature.Among the prepared catalysts,the CA-1100 catalyst exhibited the highest catalytic activity and stability.The findings of this study might be useful for the further study of the catalytic material for sustained release catalysis,including the synthesis of catalytic materials and the regulation of sustained release catalytic performance.
基金National Natural Science Foundation of China (Grant No.30973597)
文摘Biapenem, a new parenteral carbapenem, has been widely used for treating bacterial infections. A simple, effective and accurate method based on solid-phase extraction （SPE） and HPLC was developed for the quantitative determination of biapenem in human plasma. Stability and feasibility of the method was validated through a series of experiments. Using Vitamin B6 as an internal standard, analyte was separated on a Capcell Pak C18 column after SPE on Oasis hydrophilic-lipophilic balance （HLB） cartridge. The mobile phase was comprised of 0.05 mol/L NaH2PO4 （pH 5.7） and methanol （98：2, v/v） at a flow rate of 1.0 mL/min. Ultraviolet absorbance was measured at 300 nm. The calibration curve was linear in the concentration range of 0.04-50.00 μg/mL, and the lower limit of quantification was as low as 0.04 μg/mL. Recovery rates of biapenem at 0.10, 5.00, and 25.00 μg/mL were about 70%. The validated method has been successfully applied for quantifying biapenem in human samples and a pharmacokinetic study of 12 healthy volunteers who received three different doses （150, 300 and 600 mg） of biapenem by intravenous infusion. Our method has featured good accuracy and precision, and the processed sample was stable. Therefore, it can be propagated for clinical use.
文摘The new catalytic kinetic spectrophotometric method for Au（III） determination was developed and validated. It was based on the catalytic effect of gold on the oxidation of sudan red III by ammonium peroxodisulfate （（NH4）2S2O8） with nitrilo triacetic acid as an activator in microemulsion and H2SO4 medium. Under optimum conditions, there was the linearity of the calibration curve in the concentration range from 0 to 20 μg/L Au（Ⅲ） at 520 nm. The relative standard deviation was 3.0% with a correlation coefficient of 0.9986. The detection limit achieved was 9.75 × 10^-5 μg/mL. A new method using a column packed with sulfhydryl dextrose gel （SDG） as a solid-phase extractant has been developed for the preconcentration and separation of Au（Ⅲ） ions. The method has been applied to the determination of trace gold with satisfactory results.
基金the National Natural Science Foundation of China(Nos.20802063,21162032)the Foundation of the Key Laboratory of Medicinal Chemistry of Natural Resource(Yunnan University),Ministry of Education,China
文摘TMSOTf-catalyzed intramolecular seleno-arylation of tethered alkenes was performed using polystyrene-supported succini- midyl selenide as the selenium source. This catalytic process provides an efficient method for the regioselective synthesis of dihydrocoumarins possessing a seleno-functionality, followed by traceless cleavage of selenium linker to provide dihydrocoumar- ins and coumarins in good yields and purifies.
基金supported by the National Natural Science Foundation of China(Nos.21625702,21337002,21621064)the National Basic Research Program of China(No.2015CB453102)the Strategic Priority Research Program of the Chinese Academy of Science(No.XDB14010400)for the joint financial support
文摘Chlorinated paraffins（SCCPs） are widely used worldwide, and they can be released into the environment during their production, transport, usage and disposal, which pose potential risks for human health. In this work, an efficient, reliable and rapid pretreatment method based on matrix solid-phase dispersion（MSPD） was developed for the analysis of short-chain CPs（SCCPs） in human placenta by gas chromatograph-electron capture negative ion low-resolution mass spectrometry（GC-ECNI-LRMS） and gas chromatography–quadrupole time-of-flight mass spectrometry（GC–QTOF-HRMS）. The MSPD-relevant parameters including dispersing sorbent,sample-to-sorbent mass ratio, and elution solvent were optimized using the orthogonal test.Silica gel was found to be the optimal dispersing sorbent among the selected matrices. Under the optimal conditions, 44% acidic silica gel can be used as the co-sorbent to remove lipid and eluted by the mixture of hexane and dichloromethane（7：3, V/V）. The spiked recoveries of the optimized method were 77.4% and 91.4% for analyzing SCCPs in human placenta by GC-ECNI-LRMS and GC–QTOF-HRMS, and the corresponding relative standard deviations were10.2% and 5.6%, respectively. The method detection limit for the total SCCPs was 36.8 ng/g（dry weight, dw） and 19.2 ng/g（dw） as measured by GC-ECNI-LRMS and GC–QTOF-HRMS,respectively. The concentrations of SCCPs in four human placentas were in the range of
文摘A new multi-residue method based on solid-phase extraction (SPE) with centrifugation was developed for determination and quantitation of 67 pesticides in water samples. Two SPE cartridges were tested: Chromabond C18 and Oasis HLB. Parameters that influence the extraction efficiency such as the eluent volume, the sample loading volume, the addition of organic solvent to water sample, sorbent drying and elute concentration were optimized. The innovation of this work was the examination of the use of a centrifugation technique in both the drying and elution steps. When combined with centrifugation, the volume of the elution solvent was reduced to 2 mL and the time for sorbent drying decreased also to 10 min under vacuum. Under the optimized conditions, this method showed good recoveries higher than 65% - 68% for the 67 analyzed pesticides using the C18 and HLB cartridges with relative standard deviations lower than 9.7% - 12.3%. Limits of quantification were between 2 and 20 ng.L–1. The simplicity of the described method, use of less of organic solvent, short procedure time, and good recoveries demonstrate the advantages of this environmentally friendly approach for routine analysis of numerous samples.
基金supported by the Natural Sciences and Engineering Research Council of Canada,NSERC(Grant No.:IRCPJ 184412-15).
文摘Improved analytical methods for the metabolomic profiling of tissue samples are constantly needed.Currently,conventional sample preparation methods often involve tissue biopsy and/or homogenization,which disrupts the endogenous metabolome.In this study,solid-phase microextraction(SPME)fibers were used to monitor changes in endogenous compounds in homogenized and intact ovine lung tissue.Following SPME,a Biocrates AbsoluteIDQ assay was applied to make a downstream targeted metabolomics analysis and confirm the advantages of in vivo SPME metabolomics.The AbsoluteIDQ kit enabled the targeted analysis of over 100 metabolites via solid-liquid extraction and SPME.Statistical analysis revealed significant differences between conventional liquid extractions from homogenized tissue and SPME results for both homogenized and intact tissue samples.In addition,principal component analysis revealed separated clustering among all the three sample groups,indicating changes in the metabolome due to tissue homogenization and the chosen sample preparation method.Furthermore,clear differences in free metabolites were observed when extractions were performed on the intact and homogenized tissue using identical SPME procedures.Specifically,a direct comparison showed that 47 statistically distinct metabolites were detected between the homogenized and intact lung tissue samples(P<0.05)using mixed-mode SPME fibers.These changes were probably due to the disruptive homogenization of the tissue.This study's findings highlight both the importance of sample preparation in tissue-based metabolomics studies and SPME's unique ability to perform minimally invasive extractions without tissue biopsy or homogenization while providing broad metabolite coverage.
基金supported by the National Natural Science Foundation of China (Nos. 12027813 and 12105101)the Fundamental Research Funds for the National key project (No. 2019YFB1901301)
文摘In the present work,a new transient calculation method for parameters that can be used to evaluate the ability of oxygen control in a non-isothermal lead-bismuth eutectic(LBE)loop with solid-phase oxygen control was proposed.It incorporates the dissolution process of PbO particles and the oxygen mass transfer process,and an optimized method was used for finding out the optimized oxygen mass transfer coefficient.In numerical terms,three mass transfer models were simultaneously applied,and comparisons of calculated and experimental results from the CRAFT loop indicated that the optimized calculation method and these new oxygen mass transfer models were correct and applicable to other LBE loops.Through this calculation method,we aimed to optimize prediction of the distribution of oxygen and iron concentrations,time taken to establish the steady state of oxygen,and maximum dissolution/precipitation rates of corrosion products and corrosion depth across the entire LBE loop.We hope that this work will provide a potential reference for designing a more intelligent oxygen control system in the future.
基金supported by the National Natural Science Foundation of China(No.52274306)Open Fund of State Key Laboratory of Silicate Materials for Architectures(Wuhan University of Technology),China(No.SYSJJ2020-03).
文摘The enrichment of chromium in the magnetic iron chromite(Fe(Cr_(x)Fe_(1-x))_(2)O_(4))phase is crucial for the recovery and recycling of chromium in stainless-steel pickling sludge.The kinetics and reaction mechanism of the solid-phase reaction between Fe_(3)O_(4)and Cr_(2)O_(3)were investigated using the diffusion couple method at 1473 K.Not only the diffusion behavior of Fe^(2+)ions and Cr^(3+)ions was elucidated,but also the solid solution behavior of Fe^(3+)ions was discussed clearly.The microscopic morphology of the diffusion couple and the change in the concentrations of Fe and Cr cations across the diffusion layers were analyzed using scanning electron microscopy and en-ergy dispersive spectroscopy.The self-diffusion coefficients of cations were calculated based on the concentration profiles of Fe and Cr,with the results indicating that the self-diffusion coefficient of the Fe ions was consistently higher than that of the Cr ions.Additionally,a mixture of Fe_(3)O_(4)and Cr_(2)O_(3)was annealed at 1373-1473 K for 1-5 h,and the kinetic parameters were calculated by studying the phase content of the product.The phase content of Fe(Cr_(x)Fe_(1-x))_(2)O_(4)in the product was determined by Rietveld refinement of X-ray diffraction data,revealing that an activation energy(E)of 177.20 kJ·mol^(-1) and a pre-exponential factor(B)of 610.78 min^(-1)of the solid-phase reac-tion that produced the Fe(Cr_(x)Fe_(1-x))_(2)O_(4)spinel.
基金Supported by the Science and Technology Plan Projects of Fujian Province(No.2012H6008)
文摘By combining the strong and light carbon fibers （CFs） with polymers, composite materials with extraordinary mechanical properties are achieved. However, the mechanical properties of the as-prepared CF-reinforced polymer composites can not satisfy the applications in certain fields, especially for the poor interactions between CFs and the polymers. To enhance the mechanical properties of composite materials, a solid phase grafting method has been developed to improve the adhesion forces between CFs and the polymer, by modifying the surfaces of CFs. The effects of the reaction temperature, reaction time, as well as the dosage of the initiator and maleic anhydride （MAH） on the grafting efficiency have been investigated systematically. The structure and the surface chemistry of functionalized CFs have been characterized by Fourier Transform Infrared （FT-IR）, Scanning Electron Microscope （SEM）, X-ray Photoelectron Spectroscopy （XPS）, Thermogravimetric （TG）, and contact angle test. All of these results demonstrate that MAH is grafted onto the surface of CFs successfully by the solid phase grafting method. The MAH grafted CFs significantly improve its wettability, which further improves the interfacial adhesion between CFs and the polymeric matrix. The optimal reaction conditions are determined, such as the MAH/CF molar ratio, the dosage of initiator, the reaction temperature and the reaction time to be 3/1, 2%, 90℃ and 4 h, respectively. These attractive interracial characteristics of modified CFs suggest that the method proposed herein is a novel and efficient approach to develop CF-reinforced polymer composites with outstanding mechanical properties for cutting-edge industrial applications.
基金Sponsored by Anhui Province Natural Science Foundation(1408085QC52)Science and Technology Key Projects of China Tobacco Corporation(IPM-201411)
文摘Rice flour, puparium of yellow mealworm, peanut shell and sunflower seed shell are made into the culture medium, and the optimal solid-phase fermen- tation formula for M. flavoviride is figured out. In the solid-phase fermentation, Design-Expert is applied to analyze the significance of all components on the sporu- lotion, and response surface method used to optimize the fermentation medium of M. flavoviride. The results show that puparlum of yellow mealworm is the most sig- nificant component for the sporulation; and the optimal medium formula for the fermentation of M. flavoviride： 0.25-g rice flour, 0. 14-g yellow mealworm pupari- urn, 1.00-g peanut shell, and 0.25-g sunflower seedshell. In this optimal medium, the sporulation achieves 100. 013 × 10^8 spores/mL fungal liquid, 31.7% higher than that of the initial design. Application of the optimal formula will reduce the production cost, obtain higher yield of spores, produce no pollution, and offer tech- nical support for the future large-scale production.
基金Supported in part by Natural Science Foundation of Guangxi(2023GXNSFAA026246)in part by the Central Government's Guide to Local Science and Technology Development Fund(GuikeZY23055044)in part by the National Natural Science Foundation of China(62363003)。
文摘In this paper,we consider the maximal positive definite solution of the nonlinear matrix equation.By using the idea of Algorithm 2.1 in ZHANG(2013),a new inversion-free method with a stepsize parameter is proposed to obtain the maximal positive definite solution of nonlinear matrix equation X+A^(*)X|^(-α)A=Q with the case 0<α≤1.Based on this method,a new iterative algorithm is developed,and its convergence proof is given.Finally,two numerical examples are provided to show the effectiveness of the proposed method.
基金Supported by the Natural Science Foundation of Guangxi Province(Grant Nos.2023GXNSFAA026067,2024GXN SFAA010521)the National Natural Science Foundation of China(Nos.12361079,12201149,12261026).
文摘Convex feasibility problems are widely used in image reconstruction,sparse signal recovery,and other areas.This paper is devoted to considering a class of convex feasibility problem arising from sparse signal recovery.We rst derive the projection formulas for a vector onto the feasible sets.The centralized circumcentered-reection method is designed to solve the convex feasibility problem.Some numerical experiments demonstrate the feasibility and e ectiveness of the proposed algorithm,showing superior performance compared to conventional alternating projection methods.
基金Supported by the National Natural Science Foundation of China under Grant No.51975138the High-Tech Ship Scientific Research Project from the Ministry of Industry and Information Technology under Grant No.CJ05N20the National Defense Basic Research Project under Grant No.JCKY2023604C006.
文摘Marine thin plates are susceptible to welding deformation owing to their low structural stiffness.Therefore,the efficient and accurate prediction of welding deformation is essential for improving welding quality.The traditional thermal elastic-plastic finite element method(TEP-FEM)can accurately predict welding deformation.However,its efficiency is low because of the complex nonlinear transient computation,making it difficult to meet the needs of rapid engineering evaluation.To address this challenge,this study proposes an efficient prediction method for welding deformation in marine thin plate butt welds.This method is based on the coupled temperature gradient-thermal strain method(TG-TSM)that integrates inherent strain theory with a shell element finite element model.The proposed method first extracts the distribution pattern and characteristic value of welding-induced inherent strain through TEP-FEM analysis.This strain is then converted into the equivalent thermal load applied to the shell element model for rapid computation.The proposed method-particularly,the gradual temperature gradient-thermal strain method(GTG-TSM)-achieved improved computational efficiency and consistent precision.Furthermore,the proposed method required much less computation time than the traditional TEP-FEM.Thus,this study lays the foundation for future prediction of welding deformation in more complex marine thin plates.
基金Project (50930005) supported by the National Natural Science Foundation of ChinaProject (U0834002) supported by the Key Programof NSFC-Guangdong Joint Funds of China+1 种基金Project (LYM09024) supported by Training Program for Excellent Young Teachers withInnovation of Guangdong University, ChinaProject (2009ZM0121) supported by the Fundamental Research Funds for the CentralUniversities of South China University of Technology,China
文摘A procedure of low temperature solid-phase sintering（LTSS） was carried out to fabricate sintered metal fibrous media（SMFM） with high specific surface area.Stainless steel fibers which were produced by cutting process were first plated with a coarse copper coating layer by electroless plating process.A low-temperature sintering process was then completed at about 800 °C for 1 h under the protection of hydrogen atmosphere.The results show that a novel SMFM with complex surface morphology and high specific surface area（0.2 m2/g） can be obtained in this way.The effect of sintering temperature on the surface morphology and specific surface area of SMFM was studied by means of scanning electron microscopy and Brunauer-Emmett-Teller.The damage of micro-structure during the sintering process mainly contributed to the loss of specific surface area of SMFM and the optimal sintering temperature was 800 °C.
基金Project(51146010)supported by the National Natural Science Foundation of ChinaProject(S2011040003189)supported by the Doctoral Research Fund of Guangdong Natural Science Foundation,ChinaProject supported by the Fundation of Key Laboratory of Surface Functional Structure Manufacturing of Guangdong Higher Education Institutes,South China University of Technology
文摘A solid-phase sintering process for the low-cost fabrication of composite micro-channels was developed. Three kinds of composite micro-channels with metallic porous structures were designed. The sintering process was studied and optimized to obtain porous-structured micro-channels with high porosity. The flow resistance and heat transfer performance in the composite micro-channels were investigated. The composite micro-channels show acceptable flow resistance, significant enhancement of heat transfer and dramatic improvement of flow boiling stability, which indicates a promising prospect for the application in forced convective heat transfer.
基金The National Basic Research Program of China(973Program)(No.2012CB933302)the National Instrumental Research Program(No.2014YQ06077303)+1 种基金the National Natural Science Foundation of China(No.81172720,21307086)Suzhou Science and Technology Department Foundation(No.ZXG201441)
文摘A new method for simultaneous determination of four phthalate esters （ PAEs） in commercial fat-containing foods was developed by the combination of a packed nanofibers column based on solid-phase extraction with gas chromatography-flame ionization detector （ GC-FID ）. Conditions for obtaining optimum extraction efficiency such as extraction solvents, morphologies of adsorbent, ion strength and pH were investigated and optimized in detail. Under the optimized conditions, the limits of detection （LODs） found for dibutyl phthalate （DBP） , butyl benzyl phthalate （BBP）, diethyl hexyl phthalate （DEHP） and di-n-octyl phthalate （DNOP） were 50, 25, 50 and 25 ng/g, respectively. Good linearity of four PAEs was achieved in the range of 50 to 4 000 ng/g. The proposed method was applied for analyzing different kinds of fat-containing samples. PAEs in commercial fat-containing samples can be highly extracted by a packed solid-phase extraction column of 5 mg polystyrene （ PS） nanofibers. The satisfactory average recoveries were obtained in the range of 96. 7% to 102. 3% , and the relative standard deviations （RSDs） below 5% were achieved. The proposed method reduces the organic solvent consumption, the complex and tedious procedures for sample pretreatment, and achieves high sensitivity and reproducibility for the investigated PAEs.
文摘A new chemiluminescence flow system has been developed for sequential determina-tion of benzoic acid based on the reaction of the compound with copper carbonate entrapped in a solid-phase reactor. It was found that the unsaturated complex of Cu(II) and benzoic acid (1:1) has strong catalytic effect on the luminol-H2O2 chemiluminescence reaction. The calibration graph is linear over the range of 0.025 ~ 60 g/mL of benzoic acid, with a relative standard deviation of less than 3.0 %, and the detection limit is 0.01礸穖L-1. The proposed method was applied to the determination of benzoic acid content in different pharmaceutical formulations.
文摘A new pre-column derivation HPLC method with solid-phase extraction to determine captopril in human plasma was established. Derivation products were extracted by a solid-phase extraction method after the reagent, p-a-dibromoacetophenone(p-BPB), was added in the plasma samples. The samples were analyzed in a VP-ODS column with UV-detector. The calibration curve of captopril was linear within the range of 5~1000 ngmL-1 with r=0.9987, the recovery of this method was 98.652.04%, within day and between day RSD were no more than 3.4% and 8.4% respectively. To study the pharmacokinetics and the relative bioavailability of captopril tablets, two formulations of captopril tablets were given to 18 healthy male volunteers according to a randomized 2-way cross-over design with a 1-week washout period. The respective AUC0~6 , Cmax and Tmax values of the two formulations were 424.5125.7 and 439.4113.3 mghL-1; 505.9244.6 and 504.8172.2 mgL-1; 0.6620.181 and 0.5280.176 h. Results from statistics analysis showed that there were no significant difference between the AUC0~6 , Cmax and Tmax values of the two formulations, The relative bioavailability of tablets I with respect to II was 96.114.6% from AUC0~6 measurement. Bioequivalance was observed between the two tablets.
基金Supported by the National Natural Science Foundation of China(29977014)
文摘Chitosan was prepared with stressing method by blending chitin and solid alkali in a single-screw extruder at given temperature and characterized by potentiometric titration,gel permeation chromatography(GPC),infrared spectrum(IR)and carbon-13 magnetic resonance sperctroscopy(^(13)C NMR).Chitosan with a deacetylation degree(DD)of 76.1%was obtained at a mass ratio 0.2∶1∶1 for H_2 O/chitin/NaOH at 160℃for 12 min.Compared to conventional solution method(usually 1∶10 for chitin/NaOH),the alkali assumption greatly decreased.Molecular weight of chitosan obtained by solid-phase method(S3,M_w1.54×10^(5))was lower than that obtained by suspension method(Y2,M_w3.34×10^(5)).During deacetylation,molecular weight decreased with high reaction temperature and long reaction time but remained same at different initial ratios of NaOH/chitin.It might be concluded that degradation of chitosan was caused by breakout of the main chain of the oxidized chitosan catalyzed by alkali during the deactylation.IR and^(13)C NMR showed that structures of chitosans prepared by solid-phase method were not changed.
