Matrix effects can significantly hamper the accuracy and precision of the analysis results of perfluorinated acids （PFAs） in environmental solid samples. Several methods, such as standard addition, isotopically labe...Matrix effects can significantly hamper the accuracy and precision of the analysis results of perfluorinated acids （PFAs） in environmental solid samples. Several methods, such as standard addition, isotopically labeled internal standards, clean-up of SPE （solid phase extraction） eluents by dispersive graphitized carbon sorbent and substitution of eletrospray ionization （ESI） source by atmosphere pressure photoionization （APPI） source, were demonstrated for elimination of matrix effects in quantitative analysis of PFAs in solid samples. The resuRs indicate that matrix effects can be effectively eliminated by standard addition, but instrumental analysis time will be multiplied. Isotopically labeled internal standards can effectively negate matrix effects of PFAs with the same perfluorocarbon chain length, but is not valid for the other analytes. Although APPI can eliminate matrix effects for all analytes, it is only suitable for analysis of high pollution levels samples. Clean-up of SPE eluents by dispersive graphitized carbon sorbent not only effectively negate the impact of matrix effect, but also avoid frequent clean of the ESI in order to maintain instrumental sensitivity. Therefore, the best method for elimination of matrix effects is the usage of dispersive graphitized carbon sorbent for clean-up of SPE elution.展开更多
Severe matrix effects and high signal uncertainty are two key bottlenecks for the quantitative performance and wide applications of laser-induced breakdown spectroscopy(LIBS).Based on the understanding that the superp...Severe matrix effects and high signal uncertainty are two key bottlenecks for the quantitative performance and wide applications of laser-induced breakdown spectroscopy(LIBS).Based on the understanding that the superposition of both matrix effects and signal uncertainty directly affects plasma parameters and further influences spectral intensity and LIBS quantification performance,a data selection method based on plasma temperature matching(DSPTM)was proposed to reduce both matrix effects and signal uncertainty.By selecting spectra with smaller plasma temperature differences for all samples,the proposed method was able to build up the quantification model to rely more on spectra with smaller matrix effects and signal uncertainty,therefore improving final quantification performance.When applied to quantitative analysis of the zinc content in brass alloys,it was found that both accuracy and precision were improved using either a univariate model or multiple linear regression(MLR).More specifically,for the univariate model,the root-mean-square error of prediction(RMSEP),the determination coefficients(R^(2))and relative standard derivation(RSD)were improved from 3.30%,0.864 and 18.8%to 1.06%,0.986 and 13.5%,respectively;while for MLR,RMSEP,R^(2)and RSD were improved from 3.22%,0.871 and 26.2%to 1.07%,0.986 and 17.4%,respectively.These results prove that DSPTM can be used as an effective method to reduce matrix effects and improve repeatability by selecting reliable data.展开更多
The matrix effects of 14 organophosphorus pesticides in 9 kinds of vegetables matrices were preliminarily studied by gas chromatography/flame photomet- ric detection（FPD） in the paper. The matrix effects of 14 organ...The matrix effects of 14 organophosphorus pesticides in 9 kinds of vegetables matrices were preliminarily studied by gas chromatography/flame photomet- ric detection（FPD） in the paper. The matrix effects of 14 organophosphoms pesticides in 9 kinds of vegetable matrices at 0.05, 0.1 and 0.2 mg/L were compared, respectively. The results showed that matrix enhancement effect and matrix attenuation effect existed in all cases, while matrix effects did not have strong correlation with concentrations of pesticides, but were related to species of vegetables and structure and polarity of pesticides.展开更多
Formulation/pharmaceutical excipients play a major role in formulating drug candidates,with the objectives of ease of administration,targeted delivery and complete availability.Many excipients used in pharmaceutical f...Formulation/pharmaceutical excipients play a major role in formulating drug candidates,with the objectives of ease of administration,targeted delivery and complete availability.Many excipients used in pharmaceutical formulations are orphanized in preclinical drug discovery.These orphan excipients could enhance formulatability of highly lipophilic compounds.Additionally,they are safe in preclinical species when used below the LD50 values.However,when the excipients are used in formulating compounds with diverse physico-chemical properties,they pose challenges by modulating study results through their bioanalytical matrix effects.Excipients invariably present in study samples and not in the calibration curve standards cause over-/under-estimation of exposures.Thus,the mechanism by which excipients cause matrix effects and strategies to nullify these effects needs to be revisited.Furthermore,formulation excipients cause drug interactions by moderating the pathways of drug metabolizing enzymes and drug transport proteins.Although it is not possible to get rid of excipient driven interactions,it is always advised to be aware of these interactions and apply the knowledge to draw meaningful conclusions from study results.In this review,we will comprehensively discuss a)orphan excipients that have wider applications in preclinical formulations,b)bioanalytical matrix effects and possible approaches to mitigating these effects,and c)excipient driven drug interactions and strategies to alleviate the impacts of drug interactions.展开更多
Carbon dots(CDs), because of their unique properties, are being rapidly developed as important luminescent materials for imaging, sensing, and use in photonic devices. However, most of the reported fundamental propert...Carbon dots(CDs), because of their unique properties, are being rapidly developed as important luminescent materials for imaging, sensing, and use in photonic devices. However, most of the reported fundamental properties of the CDs are results of investigations conducted in the solution state, which may be completely different from those conducted in the solid state. In this work, we study the luminescence properties, photostability, and the dynamics of CDs in different matrix environments, from ensemble to the single-particle level. We observed that the properties associated with the emission centers and photostability of CDs were extremely sensitive to the local chemical environment. A better understanding of the dependence of the spectroscopic properties of CDs on the complex local chemical environment is an important step toward finding new ways of controlling the optical properties of CDs and optimizing their use in various applications.展开更多
The effect of the solid matrix and porosity of the porous medium are first introduced to the study of power-law nanofluids, and the Marangoni boundary layer flow with heat generation is investigated. Two cases of soli...The effect of the solid matrix and porosity of the porous medium are first introduced to the study of power-law nanofluids, and the Marangoni boundary layer flow with heat generation is investigated. Two cases of solid matrix of porous medium including glass balls and aluminum foam are considered. The governing partial differential equations are simplified by dimensionless variables and similarity transformations, and are solved numerically by using a shooting method with the fourth-fifth-order Runge-Kutta integration technique. It is indicated that the increase of the porosity leads to the enhancement of heat transfer in the surface of the Marangoni boundary layer flow.展开更多
The matrix thermal properties have an important impact on laser-induced plasma,as the thermal effect dominates the interaction between ns-pulsed laser and matter,especially in metals.We used a series of pure metals an...The matrix thermal properties have an important impact on laser-induced plasma,as the thermal effect dominates the interaction between ns-pulsed laser and matter,especially in metals.We used a series of pure metals and aluminum alloys to measure plasma temperature and electron density through laser-induced breakdown spectroscopy,in order to investigate the effect of matrix thermal properties on laser-induced plasma.In pure metals,a significant negative linear correlation was observed between the matrix thermal storage coefficient and plasma temperature,while a weak correlation was observed with electron density.The results indicate that metals with low thermal conductivity or specific heat capacity require less laser energy for thermal diffusion or melting and evaporation,resulting in higher ablation rates and higher plasma temperatures.However,considering ionization energy,thermal effects may be a secondary factor affecting electron density.The experiment of aluminum alloy further confirms the influence of thermal conductivity on plasma temperature and its mechanism explanation.展开更多
Steel strips are the main of steel products and flatness is an important quality indicator of steel strips. Flatness control is the key and highly difficult technique of strip mills. The bottle-neck restricting the im...Steel strips are the main of steel products and flatness is an important quality indicator of steel strips. Flatness control is the key and highly difficult technique of strip mills. The bottle-neck restricting the improvement of flatness control techniques is that the research on flatness theories and control mathematic models is not in accordance with the requirement of technique developments. To build a simple, rapid and accurate explicit formulation control model has become an urgent need for the development of flatness control technique. This paper puts forward the conception of dynamic effective matrix based on the effective matrix method for flatness control proposed by the authors under the consideration of the influence of the change of parameters in roiling processes on the effective matrix, and the concept is validated by industrial productions. Three methods of the effective matrix generation are induced： the calculation method based on the flatness prediction model; the calculation method based on the data excavation in rolling processes and the direct calculation method based on the network model. A fuzzy neural network effective matrix model is built based on the clusters, and then the network structure is optimized and the high-speed-calculation problem of the dynamic effective matrix is solved. The flatness control scheme for cold strip mills is proposed based on the dynamic effective matrix. On stand 5 of the 1 220 mm five-stand 4-high cold strip tandem mill, the industrial experiment with the control methods of tilting roll and bending roll is done by the control scheme of the static effective matrix and the dynamic effective matrix, respectively. The experiment result proves that the control effect of the dynamic effective matrix is much better than that of the static effective matrix. This paper proposes a new idea and method for the dynamic flatness control in the rolling processes of cold strip mills and develops the theory and model of the flatness control effective matrix method.展开更多
Objective With the development of analytic technologies, in-situ dating on U-bearing oxide minerals （e.g., cassiterite, rutile and baddeleyite） has been widely used in geological chronological researches and has at...Objective With the development of analytic technologies, in-situ dating on U-bearing oxide minerals （e.g., cassiterite, rutile and baddeleyite） has been widely used in geological chronological researches and has attracted remarkable attention to explore evolution of the earth and obtain age information of various geological processes. Matrix effect related studies are especially important during in-situ U- Pb dating based on Laser Ablation Multiple Collector Inductively Coupled Plasma Mass Spectrometry （LA-MC- ICPMS）. However, to our knowledge, only few thorough and systematical matrix effect study of U-bearing oxide minerals has been reported. In this study, we systematically analyzed the matrix effect of U-bearing oxide minerals in order to take place the standards which are difficult to prepare with available standards.展开更多
Laser-induced breakdown spectroscopy(LIBS)has been used for soil analysis,but its measurement accuracy is often influenced by matrix effects of different kinds of soils.In this work,a method for matrix effect suppress...Laser-induced breakdown spectroscopy(LIBS)has been used for soil analysis,but its measurement accuracy is often influenced by matrix effects of different kinds of soils.In this work,a method for matrix effect suppressing was developed using laser-induced plasma acoustic signals to correct the original spectrum,thereby improving the analysis accuracy of the soil elements.A good linear relationship was investigated firstly between the original spectral intensity and the acoustic signals.The relative standard deviations(RSDs)of Mg,Ca,Sr,and Ba elements were then calculated for both the original spectrum and the spectrum with the acoustic correction,and the RSDs were significantly reduced with the acoustic correction.Finally,calibration curves of MgⅠ285.213 nm,CaⅠ422.673 nm,SrⅠ460.733 nm and BaⅡ455.403 nm were established to assess the analytical performance of the proposed acoustic correction method.The values of the determination coefficient(R~2)of the calibration curves for Mg,Ca,Sr,and Ba elements,corrected by the acoustic amplitude,are improved from 0.9845,0.9588,0.6165,and 0.6490 to 0.9876,0.9677,0.8768,and 0.8209,respectively.The values of R~2 of the calibration curves corrected by the acoustic energy are further improved to 0.9917,0.9827,0.8835,and 0.8694,respectively.These results suggest that the matrix effect of LIBS on soils can be clearly improved by using acoustic correction,and acoustic energy correction works more efficiently than acoustic amplitude correction.This work provides a simple and efficient method for correcting matrix effects in the element analysis of soils by acoustic signals.展开更多
Matrix effect primarily impacts the accuracy and precision of zircon LA-ICP-MS U-Pb data.This paper describes three types of matrix effect in zircon LA-ICPMS U-Pb dating,i.e.,the element matrix effect,high Ddpa or ura...Matrix effect primarily impacts the accuracy and precision of zircon LA-ICP-MS U-Pb data.This paper describes three types of matrix effect in zircon LA-ICPMS U-Pb dating,i.e.,the element matrix effect,high Ddpa or uranium matrix effect and alpha dose matrix effect,and illustrates the correction of these three effects.In addition,we point out the limitation and possible problems of the existing correction methods.展开更多
The panel-type structures used in aerospace engineering can be subjected to severe highfrequency acoustic loadings in service. This paper evaluates the frequency-dependent random fatigue of panel-type structures made ...The panel-type structures used in aerospace engineering can be subjected to severe highfrequency acoustic loadings in service. This paper evaluates the frequency-dependent random fatigue of panel-type structures made of ceramic matrix composites（CMCs） under acoustic loadings. Firstly, the high-frequency random responses from the broadband random excitation will result in more stress cycles in a deinite period of time. The probability density distributions of stress amplitudes will be different in different frequency bandwidths, though the peak stress estimations are identical. Secondly, the fatigue properties of CMCs can be highly frequency-dependent. The fatigue evaluation method for the random vibration case is adopted to evaluate the fatigue damage of a representative stiffened panel structure. The frequency effect through S-N curves on random fatigue damage is numerically veriied. Finally, a parameter is demonstrated to characterize the mean vibration frequency of a random process, and hence this parameter can further be considered as a reasonable loading frequency in the fatigue tests of CMCs to obtain more reliable S-N curves.Therefore, the inluence of vibration frequency can be incorporated in the random fatigue model from the two perspectives.展开更多
Precisely optimizing the morphology of functional hybrid polymeric systems is crucial to improve its photophysical property and further extend their optoelectronic applications. The physic-chemical property of polymer...Precisely optimizing the morphology of functional hybrid polymeric systems is crucial to improve its photophysical property and further extend their optoelectronic applications. The physic-chemical property of polymeric matrix in electrospinning (ES) processing is a key factor to dominate the condensed structure of these hybrid microstructures and further improve its functionality. Herein, we set a flexible poly(ethylene oxide) (PEO) as the matrix to obtain a series of polydiarylfluorenes (including PHDPF, PODPF and PNDPF) electrospun hybrid microfibers with a robust deep-blue emission. Significantly different from the rough morphology of their poly(N-vinylcarbazole) (PVK) ES hybrid fibers, polydiarylfluorenes/PEO ES fibers showed a smooth morphology and small size with a diameter of 1∼2 µm. Besides, there is a relatively weak phase separation under rapid solvent evaporation during the ES processing, associated with the hydrogen-bonded-assisted network of PEO in ES fibers. These relative “homogeneous” ES fibers present efficient deep-blue emission (PLQY>50%), due to weak interchain aggregation. More interestingly, low fraction of planar (β) conformation appears in the uniform PODPF/PEO ES fibers, induced by the external traction force in ES processing. Meanwhile, PNDPF/PEO ES fibers present a highest sensitivity than those of other ES fibers, associated with the smallest diameter and large surface area. Finally, compared to PODPF/PVK fibers and PODPF/PEO amorphous ES fibers, PODPF/PEO ES fibers obtained from DCE solution exhibit an excellent quenching behavior toward a saturated DNT vapor, mainly due to the synergistic effect of small size, weak separation, β-conformation formation and high deep-blue emission efficiency.展开更多
Isopropyl alcohol matrix effect was found to be element specific by using the defined matrix effect factor in ICP-MS, which could not be corrected by using the conventional internal reference method. Unlike the conven...Isopropyl alcohol matrix effect was found to be element specific by using the defined matrix effect factor in ICP-MS, which could not be corrected by using the conventional internal reference method. Unlike the conventional internal reference method, the presented method allows for the analyte to behave differently from the internal reference under the influence of the matrix.展开更多
Objective To evaluate the long-term therapeutic effect and histologic result of ADM combined with autologous thin split-thickness skin graft.Methods 23 patients were treated with acellalar dermal matrix(ADM) combined ...Objective To evaluate the long-term therapeutic effect and histologic result of ADM combined with autologous thin split-thickness skin graft.Methods 23 patients were treated with acellalar dermal matrix(ADM) combined with autoiogous展开更多
An analytical method, using sector field inductively coupled plasma mass spectrometry （SF-ICP-MS） for rapid simultaneous determination of Be, Na, Mg, Si, Ca, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, As, Sn, Sb, Pb and Bi in e...An analytical method, using sector field inductively coupled plasma mass spectrometry （SF-ICP-MS） for rapid simultaneous determination of Be, Na, Mg, Si, Ca, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, As, Sn, Sb, Pb and Bi in electrolytic manganese metal, was described. At the beginning, the samples were decomposed by HNO3 and H2504, and then analyzed by SF-ICP-MS. Most of the spectral interferences could be avoided by measuring in different mass resolution modes. The matrix effects due to the excess of sulfuric acid and Mn were evaluated. Correction of matrix effects was conducted by using the internal standard elements. The optimum condition for the determination was investigated and discussed. The detection limit is in the range of 0.001-0.169 gg/L. The current method is applied to the determination of trace impurities in electrolytic manganese metal. And experiments show that good results can be obtained much faster, more accurately and conveniently by current method.展开更多
A microwave plasma torch （MPT） simultaneous spectrometer was used to study the spectral character and the matrix effect on alkali metal ions in solution. The main parameters were optimized. The microwave forward pow...A microwave plasma torch （MPT） simultaneous spectrometer was used to study the spectral character and the matrix effect on alkali metal ions in solution. The main parameters were optimized. The microwave forward power was 100 W. The argon flow rate that was used to sustain the Ar-MPT included the flow rate of carrier gas and the flow rate of support gas, which were 0. 8 and 1.0 L/min, respectively. The HC1 concentration in the solution was 0.02 mol/L. The observation height was 9. 0 ram. The detection limits of Li, Na, K, Rb, and Cs were 0. 0003, 0. 0004, 0. 009, 0.07 and 2.4 mg/L, respectively, and the resuhs obtained by the Ar-MPT were compared with those obtained by argon inductively coupled plasma（Ar-ICP） and argon microwave induced plasma（Ar-MIP）. The interference effects of several matrix elements were also studied.展开更多
Chromatographic behavior of co-eluted compounds from un-extracted drug-free plasma samples was studied by LC-MS and LC-MS/MS with positive APCI.Under soft gradient,total ion chromatogram（TIC） consisted of two major ...Chromatographic behavior of co-eluted compounds from un-extracted drug-free plasma samples was studied by LC-MS and LC-MS/MS with positive APCI.Under soft gradient,total ion chromatogram（TIC） consisted of two major peaks separated by a constant lower intensity region.Early peak（0.15-0.4 min） belongs to polar plasma compounds and consisted of smaller mass ions（m/z〈 250）;late peak（3.6-4.6 min） belongs to thermally unstable phospholipids and consisted of fragments with mlz〈300.Late peak is more sensitive to variations in chromatographic and MS parameters.Screening of most targeted cardiovascular drugs at levels lower than 50 ng/mL has been possible by LC-MS for drugs with retention factors larger than three.Matrix effects and recovery,at 20 and 200 ng/mL,were evaluated for spiked plasma samples with 15 cardiovascular drugs,by MRM-LC-MS/MS.Average recoveries were above 90%and matrix effects expressed as percent matrix factor（%MF） were above 100%,indicating enhancement character for APCI.Large uncertainties were significant for drugs with smaller masses（m/z〈 250） and retention factors lower than two.展开更多
The concentrations of SiO,Al2O,KO,NaO,CaO,MgO,Fe2Oand TiO,and loss on ignition(L.O.I.) are the main inorganic components of geological samples.Concentrations of the eight oxides and L.O.I.are also the main indicators ...The concentrations of SiO,Al2O,KO,NaO,CaO,MgO,Fe2Oand TiO,and loss on ignition(L.O.I.) are the main inorganic components of geological samples.Concentrations of the eight oxides and L.O.I.are also the main indicators of concern in the production of building ceramics.Quantitative analysis of the eight oxides and L.O.I.was performed using fiber-laserbased laser-induced breakdown spectroscopy(LIBS).A combination of continuous background deduction,full width at half maximum(FWHM) intensity integral and spectral sum normalization was proposed for data processing.After the data processing combined the continuous background deduction,FWHM intensity integral and spectral sum normalization,the mean absolute errors(MAEs) of the calibration of L.O.I.,SiO,Al2O,KO,NaO,CaO,MgO,Fe2Oand TiOwas reduced from 2.03%,12.06%,4.84%,1.10%,0.69%,0.31%,0.11%,0.20%and 0.10% to 1.80%,9.48%,2.12%,0.36%,0.58%,0.11%,0.08%,0.19% and 0.05%,respectively.This multivariate method was further introduced and discussed to improve the analysis performance.The MAEs of L.O.I.,SiO,Al2O,KO and NaO were further reduced to1.12%,2.07%,1.38%,0.35% and 0.43%,respectively.The results show that the overall prediction error can meet the requirements for the production of building ceramics.The LIBS desktop analyzer has great potential in detection applications on geological samples.展开更多
The contents ofMg, Al, Si, Ti, Cr, Mn, Fe, Co, Cu, Ga, As, Se, Cd, Sb, Pb and Bi in high purity nickel were determined by high resolution inductively coupled plasma mass spectrometry （HR-ICP-MS）. The sample was diss...The contents ofMg, Al, Si, Ti, Cr, Mn, Fe, Co, Cu, Ga, As, Se, Cd, Sb, Pb and Bi in high purity nickel were determined by high resolution inductively coupled plasma mass spectrometry （HR-ICP-MS）. The sample was dissolved in HNO3 and HCI by microwave digestion. Most of the spectral interferences could be avoided by measuring in the high resolution mode. The matrix effects because of the presence of excess HC1 and nickel were evaluated. Correction for matrix effects was made using Sc, Rh and T1 as internal standards. The optimum conditions for the determination were tested and discussed. The detection limits range from 0.012 to 1.76 ~tg/g depending on the type of elements. The applicability of the proposed method is also validated by the analysis of high purity nickel reference material （NIST SRM 671）. The relative standard deviation （RSD） is less than 3.3%. Results for determination of trace elements in high purity nickel were presented.展开更多
基金Foundation item: Projects(51108197, 51205215) supported by the National Natural Science Foundation of ChinaProjects(2011J05135, 2011J01318) supported by the Natural Science Foundation of Fujian Province, China+1 种基金Project(11QZR08) supported by the Scientific Research Foundation of Overseas Chinese Affairs Office of the State Council,ChinaProject(10BS213) supported by the Scientific Research Foundation for Advanced Talents,Huaqiao University,China
文摘Matrix effects can significantly hamper the accuracy and precision of the analysis results of perfluorinated acids （PFAs） in environmental solid samples. Several methods, such as standard addition, isotopically labeled internal standards, clean-up of SPE （solid phase extraction） eluents by dispersive graphitized carbon sorbent and substitution of eletrospray ionization （ESI） source by atmosphere pressure photoionization （APPI） source, were demonstrated for elimination of matrix effects in quantitative analysis of PFAs in solid samples. The resuRs indicate that matrix effects can be effectively eliminated by standard addition, but instrumental analysis time will be multiplied. Isotopically labeled internal standards can effectively negate matrix effects of PFAs with the same perfluorocarbon chain length, but is not valid for the other analytes. Although APPI can eliminate matrix effects for all analytes, it is only suitable for analysis of high pollution levels samples. Clean-up of SPE eluents by dispersive graphitized carbon sorbent not only effectively negate the impact of matrix effect, but also avoid frequent clean of the ESI in order to maintain instrumental sensitivity. Therefore, the best method for elimination of matrix effects is the usage of dispersive graphitized carbon sorbent for clean-up of SPE elution.
基金financial support from the Scientific Research Program for Young Talents of China National Nuclear Corporation(2020)National Natural Science Foundation of China(Nos.51906124 and 62205172)+1 种基金Shanxi Province Science and Technology Department(No.20201101013)Guoneng Bengbu Power Generation Co.,Ltd(No.20212000001)。
文摘Severe matrix effects and high signal uncertainty are two key bottlenecks for the quantitative performance and wide applications of laser-induced breakdown spectroscopy(LIBS).Based on the understanding that the superposition of both matrix effects and signal uncertainty directly affects plasma parameters and further influences spectral intensity and LIBS quantification performance,a data selection method based on plasma temperature matching(DSPTM)was proposed to reduce both matrix effects and signal uncertainty.By selecting spectra with smaller plasma temperature differences for all samples,the proposed method was able to build up the quantification model to rely more on spectra with smaller matrix effects and signal uncertainty,therefore improving final quantification performance.When applied to quantitative analysis of the zinc content in brass alloys,it was found that both accuracy and precision were improved using either a univariate model or multiple linear regression(MLR).More specifically,for the univariate model,the root-mean-square error of prediction(RMSEP),the determination coefficients(R^(2))and relative standard derivation(RSD)were improved from 3.30%,0.864 and 18.8%to 1.06%,0.986 and 13.5%,respectively;while for MLR,RMSEP,R^(2)and RSD were improved from 3.22%,0.871 and 26.2%to 1.07%,0.986 and 17.4%,respectively.These results prove that DSPTM can be used as an effective method to reduce matrix effects and improve repeatability by selecting reliable data.
文摘The matrix effects of 14 organophosphorus pesticides in 9 kinds of vegetables matrices were preliminarily studied by gas chromatography/flame photomet- ric detection（FPD） in the paper. The matrix effects of 14 organophosphoms pesticides in 9 kinds of vegetable matrices at 0.05, 0.1 and 0.2 mg/L were compared, respectively. The results showed that matrix enhancement effect and matrix attenuation effect existed in all cases, while matrix effects did not have strong correlation with concentrations of pesticides, but were related to species of vegetables and structure and polarity of pesticides.
文摘Formulation/pharmaceutical excipients play a major role in formulating drug candidates,with the objectives of ease of administration,targeted delivery and complete availability.Many excipients used in pharmaceutical formulations are orphanized in preclinical drug discovery.These orphan excipients could enhance formulatability of highly lipophilic compounds.Additionally,they are safe in preclinical species when used below the LD50 values.However,when the excipients are used in formulating compounds with diverse physico-chemical properties,they pose challenges by modulating study results through their bioanalytical matrix effects.Excipients invariably present in study samples and not in the calibration curve standards cause over-/under-estimation of exposures.Thus,the mechanism by which excipients cause matrix effects and strategies to nullify these effects needs to be revisited.Furthermore,formulation excipients cause drug interactions by moderating the pathways of drug metabolizing enzymes and drug transport proteins.Although it is not possible to get rid of excipient driven interactions,it is always advised to be aware of these interactions and apply the knowledge to draw meaningful conclusions from study results.In this review,we will comprehensively discuss a)orphan excipients that have wider applications in preclinical formulations,b)bioanalytical matrix effects and possible approaches to mitigating these effects,and c)excipient driven drug interactions and strategies to alleviate the impacts of drug interactions.
基金financial support from National Natural Science Foundation of China (No.22073046)Fundamental Research Funds for the Central Universities。
文摘Carbon dots(CDs), because of their unique properties, are being rapidly developed as important luminescent materials for imaging, sensing, and use in photonic devices. However, most of the reported fundamental properties of the CDs are results of investigations conducted in the solution state, which may be completely different from those conducted in the solid state. In this work, we study the luminescence properties, photostability, and the dynamics of CDs in different matrix environments, from ensemble to the single-particle level. We observed that the properties associated with the emission centers and photostability of CDs were extremely sensitive to the local chemical environment. A better understanding of the dependence of the spectroscopic properties of CDs on the complex local chemical environment is an important step toward finding new ways of controlling the optical properties of CDs and optimizing their use in various applications.
基金Supported by the National Natural Science Foundation of China under Grant No 51305080
文摘The effect of the solid matrix and porosity of the porous medium are first introduced to the study of power-law nanofluids, and the Marangoni boundary layer flow with heat generation is investigated. Two cases of solid matrix of porous medium including glass balls and aluminum foam are considered. The governing partial differential equations are simplified by dimensionless variables and similarity transformations, and are solved numerically by using a shooting method with the fourth-fifth-order Runge-Kutta integration technique. It is indicated that the increase of the porosity leads to the enhancement of heat transfer in the surface of the Marangoni boundary layer flow.
基金supported by the National Key Research and Development Project(Grant No.2018YFC2001100).
文摘The matrix thermal properties have an important impact on laser-induced plasma,as the thermal effect dominates the interaction between ns-pulsed laser and matter,especially in metals.We used a series of pure metals and aluminum alloys to measure plasma temperature and electron density through laser-induced breakdown spectroscopy,in order to investigate the effect of matrix thermal properties on laser-induced plasma.In pure metals,a significant negative linear correlation was observed between the matrix thermal storage coefficient and plasma temperature,while a weak correlation was observed with electron density.The results indicate that metals with low thermal conductivity or specific heat capacity require less laser energy for thermal diffusion or melting and evaporation,resulting in higher ablation rates and higher plasma temperatures.However,considering ionization energy,thermal effects may be a secondary factor affecting electron density.The experiment of aluminum alloy further confirms the influence of thermal conductivity on plasma temperature and its mechanism explanation.
基金supported by National Natural Science Foundation of China(Grant No. 50675186)Hebei Provincial Major Natural Science Foundation of China (Grant No. E2006001038)
文摘Steel strips are the main of steel products and flatness is an important quality indicator of steel strips. Flatness control is the key and highly difficult technique of strip mills. The bottle-neck restricting the improvement of flatness control techniques is that the research on flatness theories and control mathematic models is not in accordance with the requirement of technique developments. To build a simple, rapid and accurate explicit formulation control model has become an urgent need for the development of flatness control technique. This paper puts forward the conception of dynamic effective matrix based on the effective matrix method for flatness control proposed by the authors under the consideration of the influence of the change of parameters in roiling processes on the effective matrix, and the concept is validated by industrial productions. Three methods of the effective matrix generation are induced： the calculation method based on the flatness prediction model; the calculation method based on the data excavation in rolling processes and the direct calculation method based on the network model. A fuzzy neural network effective matrix model is built based on the clusters, and then the network structure is optimized and the high-speed-calculation problem of the dynamic effective matrix is solved. The flatness control scheme for cold strip mills is proposed based on the dynamic effective matrix. On stand 5 of the 1 220 mm five-stand 4-high cold strip tandem mill, the industrial experiment with the control methods of tilting roll and bending roll is done by the control scheme of the static effective matrix and the dynamic effective matrix, respectively. The experiment result proves that the control effect of the dynamic effective matrix is much better than that of the static effective matrix. This paper proposes a new idea and method for the dynamic flatness control in the rolling processes of cold strip mills and develops the theory and model of the flatness control effective matrix method.
基金financially supported by the National Natural Science Foundation of China(grants No.41503052 and 41373053)the National Science and Technology Infrastructure(grant No.DDK14-39)
文摘Objective With the development of analytic technologies, in-situ dating on U-bearing oxide minerals （e.g., cassiterite, rutile and baddeleyite） has been widely used in geological chronological researches and has attracted remarkable attention to explore evolution of the earth and obtain age information of various geological processes. Matrix effect related studies are especially important during in-situ U- Pb dating based on Laser Ablation Multiple Collector Inductively Coupled Plasma Mass Spectrometry （LA-MC- ICPMS）. However, to our knowledge, only few thorough and systematical matrix effect study of U-bearing oxide minerals has been reported. In this study, we systematically analyzed the matrix effect of U-bearing oxide minerals in order to take place the standards which are difficult to prepare with available standards.
基金financially supported by National Natural Science Foundation of China(No.12064029)by Jiangxi Provincial Natural Science Foundation(No.20202BABL202024)by the Open project program of Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province(No.ED202208094)。
文摘Laser-induced breakdown spectroscopy(LIBS)has been used for soil analysis,but its measurement accuracy is often influenced by matrix effects of different kinds of soils.In this work,a method for matrix effect suppressing was developed using laser-induced plasma acoustic signals to correct the original spectrum,thereby improving the analysis accuracy of the soil elements.A good linear relationship was investigated firstly between the original spectral intensity and the acoustic signals.The relative standard deviations(RSDs)of Mg,Ca,Sr,and Ba elements were then calculated for both the original spectrum and the spectrum with the acoustic correction,and the RSDs were significantly reduced with the acoustic correction.Finally,calibration curves of MgⅠ285.213 nm,CaⅠ422.673 nm,SrⅠ460.733 nm and BaⅡ455.403 nm were established to assess the analytical performance of the proposed acoustic correction method.The values of the determination coefficient(R~2)of the calibration curves for Mg,Ca,Sr,and Ba elements,corrected by the acoustic amplitude,are improved from 0.9845,0.9588,0.6165,and 0.6490 to 0.9876,0.9677,0.8768,and 0.8209,respectively.The values of R~2 of the calibration curves corrected by the acoustic energy are further improved to 0.9917,0.9827,0.8835,and 0.8694,respectively.These results suggest that the matrix effect of LIBS on soils can be clearly improved by using acoustic correction,and acoustic energy correction works more efficiently than acoustic amplitude correction.This work provides a simple and efficient method for correcting matrix effects in the element analysis of soils by acoustic signals.
文摘Matrix effect primarily impacts the accuracy and precision of zircon LA-ICP-MS U-Pb data.This paper describes three types of matrix effect in zircon LA-ICPMS U-Pb dating,i.e.,the element matrix effect,high Ddpa or uranium matrix effect and alpha dose matrix effect,and illustrates the correction of these three effects.In addition,we point out the limitation and possible problems of the existing correction methods.
基金supports from the National Natural Science Foundation of China (No. 11572086 , No. 11402052 )the New Century Excellent Talent in University (NCET-11-0086)+3 种基金the Natural Science Foundation of Jiangsu province (No. BK20140616 )the Fundamental Research Funds for the Central Universities and the Scientiic Research Innovation Program of Jiangsu Province College Postgraduates (KYLX_0093, KYLX15_0092)the China Scholarship Council ( 201506090047 )the Ministry of Education, Science and Technological Development of Republic of Serbia ( TR 35011 and ON 74001 )
文摘The panel-type structures used in aerospace engineering can be subjected to severe highfrequency acoustic loadings in service. This paper evaluates the frequency-dependent random fatigue of panel-type structures made of ceramic matrix composites（CMCs） under acoustic loadings. Firstly, the high-frequency random responses from the broadband random excitation will result in more stress cycles in a deinite period of time. The probability density distributions of stress amplitudes will be different in different frequency bandwidths, though the peak stress estimations are identical. Secondly, the fatigue properties of CMCs can be highly frequency-dependent. The fatigue evaluation method for the random vibration case is adopted to evaluate the fatigue damage of a representative stiffened panel structure. The frequency effect through S-N curves on random fatigue damage is numerically veriied. Finally, a parameter is demonstrated to characterize the mean vibration frequency of a random process, and hence this parameter can further be considered as a reasonable loading frequency in the fatigue tests of CMCs to obtain more reliable S-N curves.Therefore, the inluence of vibration frequency can be incorporated in the random fatigue model from the two perspectives.
基金supported by the National Natural Science Foundation of China(Nos.22075136 and 61874053)the open research fund from Anhui Province Key Laboratory of Environment-friendly Polymer Materials,Anhui Province Key Laboratory of Optoelectronic Materials Science and Technologythe State Key Laboratory of Luminescent Materials and Devices(South China University of Technology).
文摘Precisely optimizing the morphology of functional hybrid polymeric systems is crucial to improve its photophysical property and further extend their optoelectronic applications. The physic-chemical property of polymeric matrix in electrospinning (ES) processing is a key factor to dominate the condensed structure of these hybrid microstructures and further improve its functionality. Herein, we set a flexible poly(ethylene oxide) (PEO) as the matrix to obtain a series of polydiarylfluorenes (including PHDPF, PODPF and PNDPF) electrospun hybrid microfibers with a robust deep-blue emission. Significantly different from the rough morphology of their poly(N-vinylcarbazole) (PVK) ES hybrid fibers, polydiarylfluorenes/PEO ES fibers showed a smooth morphology and small size with a diameter of 1∼2 µm. Besides, there is a relatively weak phase separation under rapid solvent evaporation during the ES processing, associated with the hydrogen-bonded-assisted network of PEO in ES fibers. These relative “homogeneous” ES fibers present efficient deep-blue emission (PLQY>50%), due to weak interchain aggregation. More interestingly, low fraction of planar (β) conformation appears in the uniform PODPF/PEO ES fibers, induced by the external traction force in ES processing. Meanwhile, PNDPF/PEO ES fibers present a highest sensitivity than those of other ES fibers, associated with the smallest diameter and large surface area. Finally, compared to PODPF/PVK fibers and PODPF/PEO amorphous ES fibers, PODPF/PEO ES fibers obtained from DCE solution exhibit an excellent quenching behavior toward a saturated DNT vapor, mainly due to the synergistic effect of small size, weak separation, β-conformation formation and high deep-blue emission efficiency.
基金supported by the National Natural Science Foundation of China(Nos.40521001,40703006 and 20575061)the Chinese Ministry of Education(Nos.IRT0441 and 306021).
文摘Isopropyl alcohol matrix effect was found to be element specific by using the defined matrix effect factor in ICP-MS, which could not be corrected by using the conventional internal reference method. Unlike the conventional internal reference method, the presented method allows for the analyte to behave differently from the internal reference under the influence of the matrix.
文摘Objective To evaluate the long-term therapeutic effect and histologic result of ADM combined with autologous thin split-thickness skin graft.Methods 23 patients were treated with acellalar dermal matrix(ADM) combined with autoiogous
基金Project(21075138)supported by the National Natural Science Foundation of ChinaProject(cstc2013jcyjA10088)supported by Chongqing Natural Science Foundation,ChinaProject(KJ121311)supported by Scientific and Technological Research Program of Chongqing Municipal Education Commission,China
文摘An analytical method, using sector field inductively coupled plasma mass spectrometry （SF-ICP-MS） for rapid simultaneous determination of Be, Na, Mg, Si, Ca, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, As, Sn, Sb, Pb and Bi in electrolytic manganese metal, was described. At the beginning, the samples were decomposed by HNO3 and H2504, and then analyzed by SF-ICP-MS. Most of the spectral interferences could be avoided by measuring in different mass resolution modes. The matrix effects due to the excess of sulfuric acid and Mn were evaluated. Correction of matrix effects was conducted by using the internal standard elements. The optimum condition for the determination was investigated and discussed. The detection limit is in the range of 0.001-0.169 gg/L. The current method is applied to the determination of trace impurities in electrolytic manganese metal. And experiments show that good results can be obtained much faster, more accurately and conveniently by current method.
文摘A microwave plasma torch （MPT） simultaneous spectrometer was used to study the spectral character and the matrix effect on alkali metal ions in solution. The main parameters were optimized. The microwave forward power was 100 W. The argon flow rate that was used to sustain the Ar-MPT included the flow rate of carrier gas and the flow rate of support gas, which were 0. 8 and 1.0 L/min, respectively. The HC1 concentration in the solution was 0.02 mol/L. The observation height was 9. 0 ram. The detection limits of Li, Na, K, Rb, and Cs were 0. 0003, 0. 0004, 0. 009, 0.07 and 2.4 mg/L, respectively, and the resuhs obtained by the Ar-MPT were compared with those obtained by argon inductively coupled plasma（Ar-ICP） and argon microwave induced plasma（Ar-MIP）. The interference effects of several matrix elements were also studied.
基金supported by Dean of Scientific Research at Jordan University of Science and Technology(JUST)(No.159/ 2012)
文摘Chromatographic behavior of co-eluted compounds from un-extracted drug-free plasma samples was studied by LC-MS and LC-MS/MS with positive APCI.Under soft gradient,total ion chromatogram（TIC） consisted of two major peaks separated by a constant lower intensity region.Early peak（0.15-0.4 min） belongs to polar plasma compounds and consisted of smaller mass ions（m/z〈 250）;late peak（3.6-4.6 min） belongs to thermally unstable phospholipids and consisted of fragments with mlz〈300.Late peak is more sensitive to variations in chromatographic and MS parameters.Screening of most targeted cardiovascular drugs at levels lower than 50 ng/mL has been possible by LC-MS for drugs with retention factors larger than three.Matrix effects and recovery,at 20 and 200 ng/mL,were evaluated for spiked plasma samples with 15 cardiovascular drugs,by MRM-LC-MS/MS.Average recoveries were above 90%and matrix effects expressed as percent matrix factor（%MF） were above 100%,indicating enhancement character for APCI.Large uncertainties were significant for drugs with smaller masses（m/z〈 250） and retention factors lower than two.
基金supported by National Natural Science Foundation of China(No.62173321)the Key Research Program of Frontier Sciences,CAS(No.QYZDJ-SSW-JSC037)+2 种基金the Science and Technology Service Network Initiative Program,CAS(No.KFJ-STS-QYZD-2021-19-002)the Liaoning Provincial Natural Science Foundation(No.2021-BS-022)the Youth Innovation Promotion Association,CAS。
文摘The concentrations of SiO,Al2O,KO,NaO,CaO,MgO,Fe2Oand TiO,and loss on ignition(L.O.I.) are the main inorganic components of geological samples.Concentrations of the eight oxides and L.O.I.are also the main indicators of concern in the production of building ceramics.Quantitative analysis of the eight oxides and L.O.I.was performed using fiber-laserbased laser-induced breakdown spectroscopy(LIBS).A combination of continuous background deduction,full width at half maximum(FWHM) intensity integral and spectral sum normalization was proposed for data processing.After the data processing combined the continuous background deduction,FWHM intensity integral and spectral sum normalization,the mean absolute errors(MAEs) of the calibration of L.O.I.,SiO,Al2O,KO,NaO,CaO,MgO,Fe2Oand TiOwas reduced from 2.03%,12.06%,4.84%,1.10%,0.69%,0.31%,0.11%,0.20%and 0.10% to 1.80%,9.48%,2.12%,0.36%,0.58%,0.11%,0.08%,0.19% and 0.05%,respectively.This multivariate method was further introduced and discussed to improve the analysis performance.The MAEs of L.O.I.,SiO,Al2O,KO and NaO were further reduced to1.12%,2.07%,1.38%,0.35% and 0.43%,respectively.The results show that the overall prediction error can meet the requirements for the production of building ceramics.The LIBS desktop analyzer has great potential in detection applications on geological samples.
基金Project(21075138) supported by the National Natural Science Foundation of ChinaProject(cstc2011jjA0780) supported by Natural Science Foundation of Chongqing City,ChinaProject(KJ121311) supported by Educational Commission of Chongqing City of China
文摘The contents ofMg, Al, Si, Ti, Cr, Mn, Fe, Co, Cu, Ga, As, Se, Cd, Sb, Pb and Bi in high purity nickel were determined by high resolution inductively coupled plasma mass spectrometry （HR-ICP-MS）. The sample was dissolved in HNO3 and HCI by microwave digestion. Most of the spectral interferences could be avoided by measuring in the high resolution mode. The matrix effects because of the presence of excess HC1 and nickel were evaluated. Correction for matrix effects was made using Sc, Rh and T1 as internal standards. The optimum conditions for the determination were tested and discussed. The detection limits range from 0.012 to 1.76 ~tg/g depending on the type of elements. The applicability of the proposed method is also validated by the analysis of high purity nickel reference material （NIST SRM 671）. The relative standard deviation （RSD） is less than 3.3%. Results for determination of trace elements in high purity nickel were presented.
