In the present study, a method for the quantitative analysis of multi-components by single marker(QAMS) has been developed and validated for the simultaneous determination of echinacoside(ECH), tubuloside A, acteoside...In the present study, a method for the quantitative analysis of multi-components by single marker(QAMS) has been developed and validated for the simultaneous determination of echinacoside(ECH), tubuloside A, acteoside, isoacteoside, and2’-acetylacteoside in Cistanches Herba. ECH was used as the internal standard(IS) to obtain the relative correction factors(RCFs) of the other four phenylethanoid glycosides(PhGs);meanwhile, various influencing factors on RCFs were investigated under different conditions. The content of each component was calculated with RCF. The results were compared with those obtained by the external standard method(ESM) to verify the feasibility and accuracy of the established QAMS method. No significant difference was found in the quantitative results of 10 batches of Cistanches Herba between QAMS and ESM. The proposed QAMS method for simultaneous determination of PhGs in Cistanches Herba is accurate and feasible, providing an efficient and economical approach for the quality control of Cistanches Herba.展开更多
[Objectives]This study was conducted to establish a method of quantitative analysis of multi-components by single marker(QAMS)for the simultaneous determination of such seven chemical components as gallic acid,epicate...[Objectives]This study was conducted to establish a method of quantitative analysis of multi-components by single marker(QAMS)for the simultaneous determination of such seven chemical components as gallic acid,epicatechin,catechin,ferulic acid,chlorogenic acid,rutin and caffeic acid in Vidal grape.[Methods]The high performance liquid chromatography was carried out using a COSMOSIL C18-MS-II column(4.6 mm×250 mm,5μm)with the mobile phase acetonitrile-2%acetic acid aqueous solution(gradient elution)at a flow rate of 1.0 ml/min.The detection wavelength was 280 nm,and the column temperature was 25℃.Using caffeic acid as an internal reference,the relative correction factors between it and other six to-be-detected components,and the contents of the seven components were calculated using the correction factors.The established was compared the results with the external standard method to verify the feasibility and accuracy of the method.[Results]The seven components had a good linear relationship in the ranges of 1.060-10.60,1.419-14.19,1.062-10.62,0.2950-2.950,0.1019-1.019,0.2014-2.014,and 0.1498-1.498μg,respectively,and the relative correction factors of gallic acid,epicatechin,catechin,ferulic acid,chlorogenic acid and rutin were 0.9760,0.7806,0.3277,1.640,1.161,2.778,respectively.There was no significant difference between the results of the QAMS method and the external standard method.[Conclusions]The QAMS method using caffeic acid as an internal reference is accurate and feasible,and provides a reliable method for the quality evaluation of Vidal ice grape.展开更多
Objective: to establish multi-components by single marker (QAMS) and HPlC method for the determination of four substances (R, S) - Epigoitrin, Vitexicarpin, Indirubin and Artemisetin and to provide experimental basis ...Objective: to establish multi-components by single marker (QAMS) and HPlC method for the determination of four substances (R, S) - Epigoitrin, Vitexicarpin, Indirubin and Artemisetin and to provide experimental basis for the quality standard of Compound Yizhihao Granules. Methods: the sample treatment method was improved, and HPLC external standard method was established for the determination of four substances in Compound Yizhihao Granules. The chromatographic column was Wondersil C18 (4.6mm×250mm, 5μm), the flow rate was 1.0mL/min, the check wavelength was 245nm, the column temperature was 30℃, the sample was 20 μL, the mobile phase was acetonitrile-water. The relative correction factors (RCF) of (R, S) - Epigoitrin, Vitexicarpin, Artemisetin were determined with Indirubin as internal reference. The RCF was used to calculate the content of the substance under test, and then the content of the substance under test was determined by the external standard method to verify the feasibility of the multi-components by single marker. Results: the treatment method of the test sample was as follows: solid-liquid ratio was 1:5. Ultrasound was 45 min, trichloromethane extraction, and steam dry concentration with methanol constant volume. The results showed that the good linear ranges of (R, S) - Epigoitrin, Vitexicarpin, Indirubin and Artemisetin were 5.15-103 μ g / mL, 5.005-100.1 μ g / mL, 0.5-10 μ g / mL and 0.5115-10.23 μ g / mL, respectively. The average recoveries were 95.19%, 95.73%, 90.75%, 91.65%. The relative correction factors (RCF) of (R, S) - Epigoitrin, Vitexicarpin, Artemisetin were determined with Indirubin as internal reference was 0.2%, 0.6% and 0.3%. And the relative error of multi-components by single marker and external standard method was less than 1%. Conclusion: the multi-components by single marker method (QAMS) is simple, stable and can be used for the determination of multiple substances in Compound Yizhihao Granules.展开更多
Although inductively coupled plasma mass spectrometry(ICP-MS) retains high sensitivity and has been intensively used for the measurement of ^(99)Tc, it usually suffers from tedious, expensive, and timeconsuming sample...Although inductively coupled plasma mass spectrometry(ICP-MS) retains high sensitivity and has been intensively used for the measurement of ^(99)Tc, it usually suffers from tedious, expensive, and timeconsuming sample pretreatments due to the isobaric interferences from ^(99)Ru and ^(98)Mo^(1)H. Herein, capillary electrophoresis(CE) was applied as sample introduction system for the sensitive, and interferencefree determination of ^(99)TcO_(4)^(-) from RuO_(4)^(-), and MoO_(4)^(2-) by ICP-MS with a simple sample treatment. Compared to the conventional methods, the hyphenated CE-ICP-MS avoids the use of expensive separation resins and reduces the consumption of mineral acid, representing a simpler, more efficient and environmentally benign approach. Moreover, the proposed method exhibits higher accuracy compared with the mathematical correction method using the natural isotope ratio of ^(99)Ru and ^(101)Ru, and significantly reduces sample consumption and the amount of waste, thus remarkably alleviating the radioactive exposure to operators and the pressure of radioactive waste treatment. Under the optimized conditions, the detection limits of 25 μg/L and 0.06 μg/L were obtained for RuO_(4)^(-) and ReO_(4)^(-)(Tc was replaced by Re), respectively, with relative standard deviation(RSD) lower than 5%. In addition, efficient recoveries of RuO_(4)^(-),ReO_(4)^(-),and ^(99)TcO_(4)^(-) from simulated Hanford site groundwater were achieved. The method is expected to be a promising candidate for sensitive and accurate analysis of ^(99)Tc from contaminated environmental samples.展开更多
The reaction rate constant is a crucial kinetic parameter that governs the charge and discharge performance of batteries,particularly in high-rate and thick-electrode applications.However,conventional estimation or fi...The reaction rate constant is a crucial kinetic parameter that governs the charge and discharge performance of batteries,particularly in high-rate and thick-electrode applications.However,conventional estimation or fitting methods often overestimate the charge transfer overpotential,leading to substantial errors in reaction rate constant measurements.These inaccuracies hinder the accurate prediction of voltage profiles and overall cell performance.In this study,we propose the characteristic time-decomposed overpotential(CTDO)method,which employs a single-layer particle electrode(SLPE)structure to eliminate interference overpotentials.By leveraging the distribution of relaxation times(DRT),our method effectively isolates the characteristic time of the charge transfer process,enabling a more precise determination of the reaction rate constant.Simulation results indicate that our approach reduces measurement errors to below 2%,closely aligning with theoretical values.Furthermore,experimental validation demonstrates an 80% reduction in error compared to the conventional galvanostatic intermittent titration technique(GITT)method.Overall,this study provides a novel voltage-based approach for determining the reaction rate constant,enhancing the applicability of theoretical analysis in electrode structural design and facilitating rapid battery optimization.展开更多
[Objectives]To establish a multi-indicator quality control method for the retention of Longqing Capsule based on the principle of prescription of Chinese medicine.[Methods]High performance liquid chromatography(HPLC)w...[Objectives]To establish a multi-indicator quality control method for the retention of Longqing Capsule based on the principle of prescription of Chinese medicine.[Methods]High performance liquid chromatography(HPLC)with ShimNex CS C 18 as the column;column temperature:35℃;wavelength:270 nm;methanol-0.1%phosphoric acid solution as the mobile phase with gradient elution.[Results]The 12 components of the retention of Longqing Capsule showed good linearity within the investigated range(r≥0.9995),with the average spiked recoveries of 97.83%-100.52%and the RSD of 0.9%-2.1%.[Conclusions]The method is exclusive,sensitive,reproducible,simple and easy to use,and can provide a reference for the construction of the quality standard and control system of Longqing Capsule based on the theory of traditional Chinese medicine.展开更多
In the realm of nonlinear integrable systems,the presence of decompositions facilitates the establishment of linear superposition solutions and the derivation of novel coupled systems exhibiting nonlinear integrabilit...In the realm of nonlinear integrable systems,the presence of decompositions facilitates the establishment of linear superposition solutions and the derivation of novel coupled systems exhibiting nonlinear integrability.By focusing on single-component decompositions within the potential BKP hierarchy,it has been observed that specific linear superpositions of decomposition solutions remain consistent with the underlying equations.Moreover,through the implementation of multi-component decompositions within the potential BKP hierarchy,successful endeavors have been undertaken to formulate linear superposition solutions and novel coupled Kd V-type systems that resist decoupling via alterations in dependent variables.展开更多
Multi-component transition group metal borides(MMB_(2))have become a research hotspot due to their new composition design concepts and superior properties compared with conventional ceramics.Most of the current method...Multi-component transition group metal borides(MMB_(2))have become a research hotspot due to their new composition design concepts and superior properties compared with conventional ceramics.Most of the current methods,however,are complicated and time-consuming,the mass production remains a chal-lenge.Herein,we proposed a new high-efficiency strategy for synthesis of MMB_(2)using molten aluminum as the medium for the first time.The prepared Al-containing multi-component borides(TiZrHfNbTa)B_(2)microcrystals had a homogeneous composition with a hexagonal AlB_(2)structure and ultra-high hardness value of∼35.3 GPa,which was much higher than data reported in the literature and the rule of mix-ture estimations.Furthermore,combined with the First-principles calculation results,we found that the Poisson’s ratio(v)values exhibit a clearly ascending trend from 0.17 at VEC=3.5 to 0.18 at VEC=3.4,then to 0.201 at VEC=3.2 with the increasing of Al content.This indicates that the intrinsic toughness of multi-component boride microcrystals is obviously enhanced by the trace-doped Al elements.Besides,the fabricated Al-containing multi-component boride microcrystals have superior oxidation activation en-ergy and structural stability.The enhanced oxidation resistance is mainly attributed to the formation of a protective Al2 O3 oxide layer and the lattice distortion,both of which lead to sluggish diffusion of O_(2).These findings propose a new unexplored avenue for the fabrication of MMB_(2)materials with supe-rior comprehensive performance including ultra-hardness and intrinsically improved thermo-mechanical properties.展开更多
Fenton/Fenton-like reactions have gained popularity for their remarkable proficiency in decomposing organic pollutants,especially when enhanced by reductants addition for accel-erating the Fe2+regeneration.Nevertheles...Fenton/Fenton-like reactions have gained popularity for their remarkable proficiency in decomposing organic pollutants,especially when enhanced by reductants addition for accel-erating the Fe2+regeneration.Nevertheless,these works predominantly centered on the formation and utilization of hydroxyl radicals(•OH)in the process,neglecting the evolution of oxidant and reductant due to the difficulty in the simultaneous determination of these two components.By employing the quenching-iodometric method,we could simultaneously determine the concentrations of HSO_(3)-and peroxydisulfate(PDS).This method first employed an excess of peroxymonosulfate(PMS)to effectively quench HSO_(3)-,and then used the iodometric spectrophotometry to simultaneously determine the concentrations of PMS and PDS in the reaction system.Finally,through precise stoichiometric relationships,we could accurately calculate the concentration of HSO_(3)-.Based on this method,we achieved concentration measurements that,upon linear fitting,yielded a correlation coefficient(R^(2))surpassing 0.99,unequivocally affirming the method’s accuracy and trustworthiness.In this work,an innovation approach for determining the concentrations of HSO_(3)-(reductant)and PDS(oxidant)was explored.Additionally,the resilience of the method was verified across different pH levels and in the presence of diverse impurity ions.The results ensured precise concentration measure-ments in the real wastewater.This method was characterized by its simplicity,rapid analysis,and environmental friendliness,offering a newanalytical strategy for the determination of PDS and HSO_(3)-in environmental samples.The method enables more meticulous monitoring of chemical usage in water treatment,facilitating optimized dosing strategies and assessments of reductant-enhanced Fenton or Fenton-like system in water purification.展开更多
In paleoseismic research,defining the age of an event is relatively straightforward,but pinpointing its magnitude with precision is challenging.This difficulty primarily arises because physical parameters,such as rupt...In paleoseismic research,defining the age of an event is relatively straightforward,but pinpointing its magnitude with precision is challenging.This difficulty primarily arises because physical parameters,such as rupture area and displacement,which are intimately linked to the seismic moment,are hard to derive from paleoseismic studies.Our preceding study identified two earthquake sites in Huoshan and Guzhen,Anhui Province.While we qualitatively described the timing of these occurrences and the characteristics of sand veins,dislocations,and earthquake-induced cracks,we did not provide quantitative estimates of their magnitude or seismogenic faults.Consequently,these findings were insufficient for assessing regional seismic risks or determining the potential magnitude of specific faults.This study employs two empirical relationships:one between the farthest distribution distance based on liquefaction from earthquake-induced events and magnitude,and the other concerning the intensityepicenter distance-magnitude relationship.Through these relationships,we analyze the sandy soil liquefaction and earthquake-induced cracks quantitatively.The analysis includes magnitude estimation and seismogenic fault evaluation for the sandy soil liquefaction and crack remnants of the Huoshan Daijiayuan earthquake,as well as the dislocation and crack remnants of the Guzhen Gaixia earthquake.The findings indicate that the Huoshan Daijiayuan site records two paleoseismic events.The first event transpired after 850 BC,and the second after 550 BC,with a gap of approximately 300 years between them;both had a seismic magnitude(M_(S))of around 6.0.The likely seismogenic fault for the Huoshan Daijiayuan earthquake is the Luoerling-Tudiling fault.Meanwhile,the paleoseismic site in Guzhen Gaixia documents two seismic events occurring during 2350-2050 BC,both with a seismic magnitude(MS)of approximately 6½.The Tancheng-Lujiang fault zone is likely the seismogenic fault associated with the Guzhen Gaixia earthquake site.展开更多
The hardening mechanism of multi-component carbide ceramic has been investigated in detail through a combination of experiments,first-principles calculations,and ab initio molecular dynamics(AIMD).Eight dense carbide ...The hardening mechanism of multi-component carbide ceramic has been investigated in detail through a combination of experiments,first-principles calculations,and ab initio molecular dynamics(AIMD).Eight dense carbide ceramics were prepared by spark plasma sintering.Compulsorily,all the multi-component carbide samples have similar carbon content,grain size,and uniform compositional distribution by optimizing the sintering process and adjusting the initial raw materials.Hence the interference of other factors on the hardness of multi-component carbide ceramics is minimized.The effects of changes in the elemental species on the lattice distortion,bond strength,bonding properties,and electronic structure of multi-component carbide ceramics were thoroughly analyzed.These results show that the hardening of multi-component carbide ceramic can be attributed to the coupling of solid solution strengthening caused by lattice distortion and covalent bond strengthening.Besides,the“host lattice”of multi-component carbide ceramics is defined based on the concept of supporting lattice.The present work is of great significance for a deeper understanding of the hardening mechanism of multi-component carbide ceramics and the design of superhard multi-component carbides.展开更多
A convenient photocatalytic multi-component reaction of alkenes,quinoxalin-2(1H)-ones,and diazo compounds has been developed in the presence of water.A number of ester-containing quinoxalin-2(1H)-ones could be efficie...A convenient photocatalytic multi-component reaction of alkenes,quinoxalin-2(1H)-ones,and diazo compounds has been developed in the presence of water.A number of ester-containing quinoxalin-2(1H)-ones could be efficiently obtained in moderate to good yields at room temperature.This metal-free visiblelight-driven tandem reaction was conducted through proton-coupled electron transfer(PCET)process using water as the hydrogen donor and 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene(4CzIPN)as the photocatalyst.展开更多
This study demonstrates the fabrication of mesoporous tungsten trioxide(WO_(3))-decorated flexible polyimide(PI)electrodes for the highly sensitive detection of catechol(CC)and hydroquinone(HQ),two environmental pollu...This study demonstrates the fabrication of mesoporous tungsten trioxide(WO_(3))-decorated flexible polyimide(PI)electrodes for the highly sensitive detection of catechol(CC)and hydroquinone(HQ),two environmental pollutants.Organic-inorganic composite dots are formed on flexible PI electrodes using evaporation-induced self-assembly(EISA)and electrospray methods.The EISA process is induced by a temperature gradient during electrospray,and the heated substrate partially decomposes the organic parts etched by O_(2) plasma,creating mesoporous structures.Differential pulse voltammetry and cyclic voltammetry demonstrate a linear correlation between analyte concentration and the electrochemical response.Computational studies support the spontaneous adsorption of CC and HQ molecules on model WO_(3) surfaces.The proposed sensor shows high sensitivity,a wide linear range,and a low detection limit for both individual and simultaneous determination of CC and HQ.Real sample analysis on river water confirms practical applicability.The WO_(3)-decorated PI electrode presents an efficient and reliable approach for detecting these pollutants,contributing to environmental safety measures.展开更多
Objective:A TLCS method was established for the determination of the content of Shenbei Beigua ointment,and the product quality of six samples from two formulations was evaluated.Methods:The determination method was t...Objective:A TLCS method was established for the determination of the content of Shenbei Beigua ointment,and the product quality of six samples from two formulations was evaluated.Methods:The determination method was thin-layer chromatography scanning(TLCS),using a developing solvent composed of ethyl acetate–methanol–strong ammonia water(17:2:1).The plates were heated at 105°C for 5 minutes,then sprayed with a mixture of dilute bismuth potassium iodide and 1%ferric chloride in ethanol(10:1),and scanned at a wavelength of 500 nm.Results:Peimine showed good linearity in the concentration range of 0.21–2.1μg with a correlation coefficient of r=0.9997,and Peiminine also exhibited good linearity in the same range with r=0.9995.The accuracy was≥95.0%,and the relative standard deviation(RSD)was≤5.0%(n=6).Conclusion:This method allows for the simultaneous determination of peimine and peiminine,providing a reliable reference for the quality control of the product.展开更多
Instantaneous Global Navigation Satellite System(GNSS)attitude determination method which achieves real-time attitude determination using GNSS signal has been extensively studied,particularly the one using a priori at...Instantaneous Global Navigation Satellite System(GNSS)attitude determination method which achieves real-time attitude determination using GNSS signal has been extensively studied,particularly the one using a priori attitude information replacing the code measurements to enhance the successful rate for ambiguity resolution.However,there exists a key limitation that this method relies on considerable Monte Carlo sampling particles to construct the pdf of ambiguities,resulting in significant computational burdens.To address this limitation,this paper provides a rapid single-epoch GNSS attitude determination method based on a priori attitude information.It utilizes a second-order Taylor expansion to analytically estimate the covariance of the baseline conditioned on a priori attitude information.This is followed by deriving the float solution and covariance of ambiguities,which are then processed using the standard LAMBDA method for integer ambiguity resolution.Experimental results demonstrate that our method is both efficient and accurate,significantly reducing computational costs compared to previous methods,thereby enhancing its applicability for GNSS-based attitude determination.展开更多
Nighttime navigation faces challenges from limited data and interference,especially when satellite signals are unavailable.Leveraging lunar polarized light,polarization navigation offers a promising solution for night...Nighttime navigation faces challenges from limited data and interference,especially when satellite signals are unavailable.Leveraging lunar polarized light,polarization navigation offers a promising solution for nighttime autonomous navigation.Current algorithms,however,are limited by the requirement for known horizontal attitudes,restricting applications.This study introduces an autonomous 3-D attitude determination method to overcome this limitation.Our approach utilizes the Angle of Polarization(AOP)at night to extract neutral points from the AOP pattern.This allows for the calculation of polarization meridian plane information for attitude determination.Subsequently,we present an optimized Polarization TRIAD(Pol-TRIAD)algorithm to acquire the 3-D attitude.The proposed method outperforms the existing approaches in outdoor experiments by achieving lower Root Mean Square Error(RMSE).For one baseline attitude,it improves pitch by 31.7%,roll by 21.7%,and yaw by 2.6%,while for the attitude with a larger tilt angle,the improvements are 64.4%,30.4%,and 9.1%,respectively.展开更多
Navigation satellites generally use satellite-ground and inter-satellite observation data for precise orbit determination.In orbit determination,the satellite position is often referenced to the satellite’s centroid,...Navigation satellites generally use satellite-ground and inter-satellite observation data for precise orbit determination.In orbit determination,the satellite position is often referenced to the satellite’s centroid,while the observational measurements are referenced to the satellite’s antenna phase center.The deviation between the satellite’s centroid and the antenna phase center forms the satellite antenna phase center error,which affects the precision of orbit determination.This paper takes a global navigation satellite system(GNSS)MEO satellite as an example and analyzes the actual situation of the satellite antenna phase center deviation and phase center variation based on the ground calibration data of the in-orbit satellite antenna phase center and the satellite’s in-orbit working status.The analysis shows that the antenna phase center variation caused by the satellite’s in-orbit operation is only at the centimeter level,which has a limited impact on orbit determination accuracy.The main source of precise orbit determination error is the satellite antenna phase center deviation,which can be corrected using ground calibration data.展开更多
The exploratory synthesis and structural characterization of twodimensional(2D)honeycomb structured Ru-based compounds are key focuses in inorganic materials research,due to the various exotic electronic states arisin...The exploratory synthesis and structural characterization of twodimensional(2D)honeycomb structured Ru-based compounds are key focuses in inorganic materials research,due to the various exotic electronic states arising from the interplay of electron correlations and spinorbit coupling.Among these compounds,α-RuCl_(3) and RuBr_(3) are considered as the most promising candidates for quantum spin liquid(QSL)materials[1–3].As a homolog,α-RuI3 has attracted significant interest,but it still remains relatively unexplored.Recently,it was synthesized by high-temperature and high-pressure solid-state reaction,but reported to be different crystal structures by independent groups.Ni et al.and Nawa et al.considerα-RuI3 to be R-3(3R)and P-31c(2H)space group,respectively[4,5].Both structures have typical 2D characteristics,in which the edge-sharing RuI6 octahedra form honeycomb layers stacked along the c-axis.The primary difference lies in that the honeycomb layers stack in ABCABC mode in the 3R phase,while in ABAB mode in the 2H phase(Fig.S1).Yang et al.discussed the stability of 3R and 2H polymorphs in terms of the total energies and dynamics,finding both structures are stable.However,the total energy of the 2H phase is slightly higher,2.58 meV than that of the 3R analog[6].When it comes to the conductivity behaviour,α-RuCl3 andα-RuBr_(3) are semiconductors as normally observed in QSL materials.In contrast,α-RuI_(3) exhibits metallic response.In 2D materials,the band structure may be drastically modified by altering the stacking order[7].Hence,determining the crystal structure ofα-RuI_(3) is urgently required,which is a key step in comprehensive and in-depth analysis of its physical properties.展开更多
The deployment of the low earth orbit(LEO)satellites provides a large number of signals of opportunity(SOPs),unmanned aerial vehicle(UAV)positioning and navigation via LEO-SOPs have re-ceived much attention.Current re...The deployment of the low earth orbit(LEO)satellites provides a large number of signals of opportunity(SOPs),unmanned aerial vehicle(UAV)positioning and navigation via LEO-SOPs have re-ceived much attention.Current research is focused on Doppler positioning techniques,which require the collaboration of multiple satellites(≥3).However,the dynamic changes of LEO satellites weaken the generalization ability of Doppler positioning.In this paper,a direct position determination(DPD)method with uniform circular array(UCA)is proposed for UAV positioning from the perspective of the spatial spectrum estimation of LEO-SOPs.The proposed method employs the orthogonality between the signal and noise subspaces of the covariance matrix of the different received SOPs to establish the cost function for UAV’s coordinate.Instead of the multiple dimen-sional search,a root mean square propagation(RM-SProp)gradient optimizer with an adaptive learning rate is developed to find the coordinate of UAV.The effectiveness and robustness of the proposed method are verified using numerical data generated from the systems tool kit(STK).展开更多
基金National Key R&D Program of China(Grant Nos.2017YFC1702400,2018YFC1707300 and 2018YFC1707904)
文摘In the present study, a method for the quantitative analysis of multi-components by single marker(QAMS) has been developed and validated for the simultaneous determination of echinacoside(ECH), tubuloside A, acteoside, isoacteoside, and2’-acetylacteoside in Cistanches Herba. ECH was used as the internal standard(IS) to obtain the relative correction factors(RCFs) of the other four phenylethanoid glycosides(PhGs);meanwhile, various influencing factors on RCFs were investigated under different conditions. The content of each component was calculated with RCF. The results were compared with those obtained by the external standard method(ESM) to verify the feasibility and accuracy of the established QAMS method. No significant difference was found in the quantitative results of 10 batches of Cistanches Herba between QAMS and ESM. The proposed QAMS method for simultaneous determination of PhGs in Cistanches Herba is accurate and feasible, providing an efficient and economical approach for the quality control of Cistanches Herba.
基金Natural Science Foundation Project of Liaoning Provincial Science and Technology Department(20180550846)。
文摘[Objectives]This study was conducted to establish a method of quantitative analysis of multi-components by single marker(QAMS)for the simultaneous determination of such seven chemical components as gallic acid,epicatechin,catechin,ferulic acid,chlorogenic acid,rutin and caffeic acid in Vidal grape.[Methods]The high performance liquid chromatography was carried out using a COSMOSIL C18-MS-II column(4.6 mm×250 mm,5μm)with the mobile phase acetonitrile-2%acetic acid aqueous solution(gradient elution)at a flow rate of 1.0 ml/min.The detection wavelength was 280 nm,and the column temperature was 25℃.Using caffeic acid as an internal reference,the relative correction factors between it and other six to-be-detected components,and the contents of the seven components were calculated using the correction factors.The established was compared the results with the external standard method to verify the feasibility and accuracy of the method.[Results]The seven components had a good linear relationship in the ranges of 1.060-10.60,1.419-14.19,1.062-10.62,0.2950-2.950,0.1019-1.019,0.2014-2.014,and 0.1498-1.498μg,respectively,and the relative correction factors of gallic acid,epicatechin,catechin,ferulic acid,chlorogenic acid and rutin were 0.9760,0.7806,0.3277,1.640,1.161,2.778,respectively.There was no significant difference between the results of the QAMS method and the external standard method.[Conclusions]The QAMS method using caffeic acid as an internal reference is accurate and feasible,and provides a reliable method for the quality evaluation of Vidal ice grape.
文摘Objective: to establish multi-components by single marker (QAMS) and HPlC method for the determination of four substances (R, S) - Epigoitrin, Vitexicarpin, Indirubin and Artemisetin and to provide experimental basis for the quality standard of Compound Yizhihao Granules. Methods: the sample treatment method was improved, and HPLC external standard method was established for the determination of four substances in Compound Yizhihao Granules. The chromatographic column was Wondersil C18 (4.6mm×250mm, 5μm), the flow rate was 1.0mL/min, the check wavelength was 245nm, the column temperature was 30℃, the sample was 20 μL, the mobile phase was acetonitrile-water. The relative correction factors (RCF) of (R, S) - Epigoitrin, Vitexicarpin, Artemisetin were determined with Indirubin as internal reference. The RCF was used to calculate the content of the substance under test, and then the content of the substance under test was determined by the external standard method to verify the feasibility of the multi-components by single marker. Results: the treatment method of the test sample was as follows: solid-liquid ratio was 1:5. Ultrasound was 45 min, trichloromethane extraction, and steam dry concentration with methanol constant volume. The results showed that the good linear ranges of (R, S) - Epigoitrin, Vitexicarpin, Indirubin and Artemisetin were 5.15-103 μ g / mL, 5.005-100.1 μ g / mL, 0.5-10 μ g / mL and 0.5115-10.23 μ g / mL, respectively. The average recoveries were 95.19%, 95.73%, 90.75%, 91.65%. The relative correction factors (RCF) of (R, S) - Epigoitrin, Vitexicarpin, Artemisetin were determined with Indirubin as internal reference was 0.2%, 0.6% and 0.3%. And the relative error of multi-components by single marker and external standard method was less than 1%. Conclusion: the multi-components by single marker method (QAMS) is simple, stable and can be used for the determination of multiple substances in Compound Yizhihao Granules.
基金the National Natural Science Foundation of China (Nos. U1867205, 21622508, and 21575092)Study on Physical/Chemical Characteristics Related to the Migration of Key Nuclides under Simulated Disposal Conditions (Phase Ⅱ) (Contract No. KGES 2019(170), dated February 21, 2019.) for financial support。
文摘Although inductively coupled plasma mass spectrometry(ICP-MS) retains high sensitivity and has been intensively used for the measurement of ^(99)Tc, it usually suffers from tedious, expensive, and timeconsuming sample pretreatments due to the isobaric interferences from ^(99)Ru and ^(98)Mo^(1)H. Herein, capillary electrophoresis(CE) was applied as sample introduction system for the sensitive, and interferencefree determination of ^(99)TcO_(4)^(-) from RuO_(4)^(-), and MoO_(4)^(2-) by ICP-MS with a simple sample treatment. Compared to the conventional methods, the hyphenated CE-ICP-MS avoids the use of expensive separation resins and reduces the consumption of mineral acid, representing a simpler, more efficient and environmentally benign approach. Moreover, the proposed method exhibits higher accuracy compared with the mathematical correction method using the natural isotope ratio of ^(99)Ru and ^(101)Ru, and significantly reduces sample consumption and the amount of waste, thus remarkably alleviating the radioactive exposure to operators and the pressure of radioactive waste treatment. Under the optimized conditions, the detection limits of 25 μg/L and 0.06 μg/L were obtained for RuO_(4)^(-) and ReO_(4)^(-)(Tc was replaced by Re), respectively, with relative standard deviation(RSD) lower than 5%. In addition, efficient recoveries of RuO_(4)^(-),ReO_(4)^(-),and ^(99)TcO_(4)^(-) from simulated Hanford site groundwater were achieved. The method is expected to be a promising candidate for sensitive and accurate analysis of ^(99)Tc from contaminated environmental samples.
基金supported by the National Key R&D Program of China 2022YFB2404300the National Natural Science Foundation of China U22B2069the China Postdoctoral Science Foundation 2024M761006。
文摘The reaction rate constant is a crucial kinetic parameter that governs the charge and discharge performance of batteries,particularly in high-rate and thick-electrode applications.However,conventional estimation or fitting methods often overestimate the charge transfer overpotential,leading to substantial errors in reaction rate constant measurements.These inaccuracies hinder the accurate prediction of voltage profiles and overall cell performance.In this study,we propose the characteristic time-decomposed overpotential(CTDO)method,which employs a single-layer particle electrode(SLPE)structure to eliminate interference overpotentials.By leveraging the distribution of relaxation times(DRT),our method effectively isolates the characteristic time of the charge transfer process,enabling a more precise determination of the reaction rate constant.Simulation results indicate that our approach reduces measurement errors to below 2%,closely aligning with theoretical values.Furthermore,experimental validation demonstrates an 80% reduction in error compared to the conventional galvanostatic intermittent titration technique(GITT)method.Overall,this study provides a novel voltage-based approach for determining the reaction rate constant,enhancing the applicability of theoretical analysis in electrode structural design and facilitating rapid battery optimization.
基金Supported by Provincial University Scientific Research Platform Team Project of Guizhou Provincial Department of Education(Qianjiaoji[2022]No.010).
文摘[Objectives]To establish a multi-indicator quality control method for the retention of Longqing Capsule based on the principle of prescription of Chinese medicine.[Methods]High performance liquid chromatography(HPLC)with ShimNex CS C 18 as the column;column temperature:35℃;wavelength:270 nm;methanol-0.1%phosphoric acid solution as the mobile phase with gradient elution.[Results]The 12 components of the retention of Longqing Capsule showed good linearity within the investigated range(r≥0.9995),with the average spiked recoveries of 97.83%-100.52%and the RSD of 0.9%-2.1%.[Conclusions]The method is exclusive,sensitive,reproducible,simple and easy to use,and can provide a reference for the construction of the quality standard and control system of Longqing Capsule based on the theory of traditional Chinese medicine.
基金sponsored by the National Natural Science Foundations of China under Grant Nos.12301315,12235007,11975131the Zhejiang Provincial Natural Science Foundation of China under Grant No.LQ20A010009。
文摘In the realm of nonlinear integrable systems,the presence of decompositions facilitates the establishment of linear superposition solutions and the derivation of novel coupled systems exhibiting nonlinear integrability.By focusing on single-component decompositions within the potential BKP hierarchy,it has been observed that specific linear superpositions of decomposition solutions remain consistent with the underlying equations.Moreover,through the implementation of multi-component decompositions within the potential BKP hierarchy,successful endeavors have been undertaken to formulate linear superposition solutions and novel coupled Kd V-type systems that resist decoupling via alterations in dependent variables.
基金financially supported by the National Natural Science Foundation of China(Nos.52271033 and 52071179)the Key program of National Natural Science Foundation of China(No.51931003)+2 种基金Natural Science Foundation of Jiangsu Province,China(No.BK20221493)Jiangsu Province Leading Edge Technology Basic Research Major Project(No.BK20222014)Foundation of“Qinglan Project”for Colleges and Universities in Jiangsu Province.
文摘Multi-component transition group metal borides(MMB_(2))have become a research hotspot due to their new composition design concepts and superior properties compared with conventional ceramics.Most of the current methods,however,are complicated and time-consuming,the mass production remains a chal-lenge.Herein,we proposed a new high-efficiency strategy for synthesis of MMB_(2)using molten aluminum as the medium for the first time.The prepared Al-containing multi-component borides(TiZrHfNbTa)B_(2)microcrystals had a homogeneous composition with a hexagonal AlB_(2)structure and ultra-high hardness value of∼35.3 GPa,which was much higher than data reported in the literature and the rule of mix-ture estimations.Furthermore,combined with the First-principles calculation results,we found that the Poisson’s ratio(v)values exhibit a clearly ascending trend from 0.17 at VEC=3.5 to 0.18 at VEC=3.4,then to 0.201 at VEC=3.2 with the increasing of Al content.This indicates that the intrinsic toughness of multi-component boride microcrystals is obviously enhanced by the trace-doped Al elements.Besides,the fabricated Al-containing multi-component boride microcrystals have superior oxidation activation en-ergy and structural stability.The enhanced oxidation resistance is mainly attributed to the formation of a protective Al2 O3 oxide layer and the lattice distortion,both of which lead to sluggish diffusion of O_(2).These findings propose a new unexplored avenue for the fabrication of MMB_(2)materials with supe-rior comprehensive performance including ultra-hardness and intrinsically improved thermo-mechanical properties.
基金supported by National Natural Scienc Foundation of China(No.52400097)the Nanqiang Young Talents Supporting Program from Xiamen University.
文摘Fenton/Fenton-like reactions have gained popularity for their remarkable proficiency in decomposing organic pollutants,especially when enhanced by reductants addition for accel-erating the Fe2+regeneration.Nevertheless,these works predominantly centered on the formation and utilization of hydroxyl radicals(•OH)in the process,neglecting the evolution of oxidant and reductant due to the difficulty in the simultaneous determination of these two components.By employing the quenching-iodometric method,we could simultaneously determine the concentrations of HSO_(3)-and peroxydisulfate(PDS).This method first employed an excess of peroxymonosulfate(PMS)to effectively quench HSO_(3)-,and then used the iodometric spectrophotometry to simultaneously determine the concentrations of PMS and PDS in the reaction system.Finally,through precise stoichiometric relationships,we could accurately calculate the concentration of HSO_(3)-.Based on this method,we achieved concentration measurements that,upon linear fitting,yielded a correlation coefficient(R^(2))surpassing 0.99,unequivocally affirming the method’s accuracy and trustworthiness.In this work,an innovation approach for determining the concentrations of HSO_(3)-(reductant)and PDS(oxidant)was explored.Additionally,the resilience of the method was verified across different pH levels and in the presence of diverse impurity ions.The results ensured precise concentration measure-ments in the real wastewater.This method was characterized by its simplicity,rapid analysis,and environmental friendliness,offering a newanalytical strategy for the determination of PDS and HSO_(3)-in environmental samples.The method enables more meticulous monitoring of chemical usage in water treatment,facilitating optimized dosing strategies and assessments of reductant-enhanced Fenton or Fenton-like system in water purification.
基金supported by the Spark Program of Earthquake Sciences(No.XH23020YA)Joint Open Fund of Mengcheng National Geophysical Observatory(No.MEMGO-202411)Hefei government special technology research project(2024BFFFD02048).
文摘In paleoseismic research,defining the age of an event is relatively straightforward,but pinpointing its magnitude with precision is challenging.This difficulty primarily arises because physical parameters,such as rupture area and displacement,which are intimately linked to the seismic moment,are hard to derive from paleoseismic studies.Our preceding study identified two earthquake sites in Huoshan and Guzhen,Anhui Province.While we qualitatively described the timing of these occurrences and the characteristics of sand veins,dislocations,and earthquake-induced cracks,we did not provide quantitative estimates of their magnitude or seismogenic faults.Consequently,these findings were insufficient for assessing regional seismic risks or determining the potential magnitude of specific faults.This study employs two empirical relationships:one between the farthest distribution distance based on liquefaction from earthquake-induced events and magnitude,and the other concerning the intensityepicenter distance-magnitude relationship.Through these relationships,we analyze the sandy soil liquefaction and earthquake-induced cracks quantitatively.The analysis includes magnitude estimation and seismogenic fault evaluation for the sandy soil liquefaction and crack remnants of the Huoshan Daijiayuan earthquake,as well as the dislocation and crack remnants of the Guzhen Gaixia earthquake.The findings indicate that the Huoshan Daijiayuan site records two paleoseismic events.The first event transpired after 850 BC,and the second after 550 BC,with a gap of approximately 300 years between them;both had a seismic magnitude(M_(S))of around 6.0.The likely seismogenic fault for the Huoshan Daijiayuan earthquake is the Luoerling-Tudiling fault.Meanwhile,the paleoseismic site in Guzhen Gaixia documents two seismic events occurring during 2350-2050 BC,both with a seismic magnitude(MS)of approximately 6½.The Tancheng-Lujiang fault zone is likely the seismogenic fault associated with the Guzhen Gaixia earthquake site.
基金financially supported by the National Natural Science Foundation of China(Nos.52032002,52372060,51972081,and U22A20128)the National Safety Academic Foundation(No.U2130103)+1 种基金the National Key Laboratory of Precision Hot Processing of Metals(No.61429092300305)Heilongjiang Touyan Team Program are gratefully acknowledged.
文摘The hardening mechanism of multi-component carbide ceramic has been investigated in detail through a combination of experiments,first-principles calculations,and ab initio molecular dynamics(AIMD).Eight dense carbide ceramics were prepared by spark plasma sintering.Compulsorily,all the multi-component carbide samples have similar carbon content,grain size,and uniform compositional distribution by optimizing the sintering process and adjusting the initial raw materials.Hence the interference of other factors on the hardness of multi-component carbide ceramics is minimized.The effects of changes in the elemental species on the lattice distortion,bond strength,bonding properties,and electronic structure of multi-component carbide ceramics were thoroughly analyzed.These results show that the hardening of multi-component carbide ceramic can be attributed to the coupling of solid solution strengthening caused by lattice distortion and covalent bond strengthening.Besides,the“host lattice”of multi-component carbide ceramics is defined based on the concept of supporting lattice.The present work is of great significance for a deeper understanding of the hardening mechanism of multi-component carbide ceramics and the design of superhard multi-component carbides.
基金supported by Sichuan Science and Technology Program(No.2023NSFSC0101)the 2024 Provincial platform project of Chengdu Normal University(No.GNFZ202404)+1 种基金Natural Science Foundation of Shandong Province(No.ZR2021MB065)National Natural Science Foundation of China(No.22101237)。
文摘A convenient photocatalytic multi-component reaction of alkenes,quinoxalin-2(1H)-ones,and diazo compounds has been developed in the presence of water.A number of ester-containing quinoxalin-2(1H)-ones could be efficiently obtained in moderate to good yields at room temperature.This metal-free visiblelight-driven tandem reaction was conducted through proton-coupled electron transfer(PCET)process using water as the hydrogen donor and 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene(4CzIPN)as the photocatalyst.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF),funded by the Ministry of Education(RS-202300243390 and 2020R1A5A1018052)supported by the Basic Science Research Program through the National Research Foundation of Korea,funded by the Ministry of Education(2022R1A3B1078163)supported by the Technology Innovation Program(Publicprivate joint investment semiconductor R&D program[K-CHIPS])to foster high-quality human resources(RS-2023-00235484)funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea)(1415187770)。
文摘This study demonstrates the fabrication of mesoporous tungsten trioxide(WO_(3))-decorated flexible polyimide(PI)electrodes for the highly sensitive detection of catechol(CC)and hydroquinone(HQ),two environmental pollutants.Organic-inorganic composite dots are formed on flexible PI electrodes using evaporation-induced self-assembly(EISA)and electrospray methods.The EISA process is induced by a temperature gradient during electrospray,and the heated substrate partially decomposes the organic parts etched by O_(2) plasma,creating mesoporous structures.Differential pulse voltammetry and cyclic voltammetry demonstrate a linear correlation between analyte concentration and the electrochemical response.Computational studies support the spontaneous adsorption of CC and HQ molecules on model WO_(3) surfaces.The proposed sensor shows high sensitivity,a wide linear range,and a low detection limit for both individual and simultaneous determination of CC and HQ.Real sample analysis on river water confirms practical applicability.The WO_(3)-decorated PI electrode presents an efficient and reliable approach for detecting these pollutants,contributing to environmental safety measures.
文摘Objective:A TLCS method was established for the determination of the content of Shenbei Beigua ointment,and the product quality of six samples from two formulations was evaluated.Methods:The determination method was thin-layer chromatography scanning(TLCS),using a developing solvent composed of ethyl acetate–methanol–strong ammonia water(17:2:1).The plates were heated at 105°C for 5 minutes,then sprayed with a mixture of dilute bismuth potassium iodide and 1%ferric chloride in ethanol(10:1),and scanned at a wavelength of 500 nm.Results:Peimine showed good linearity in the concentration range of 0.21–2.1μg with a correlation coefficient of r=0.9997,and Peiminine also exhibited good linearity in the same range with r=0.9995.The accuracy was≥95.0%,and the relative standard deviation(RSD)was≤5.0%(n=6).Conclusion:This method allows for the simultaneous determination of peimine and peiminine,providing a reliable reference for the quality control of the product.
基金supported by the Research Grants Council of the Hong Kong Special Administrative Region,China(Nos.25202520,15214523)the Fundamental Research Funds for the Central Universities,China(No.YWF-22-L-805)。
文摘Instantaneous Global Navigation Satellite System(GNSS)attitude determination method which achieves real-time attitude determination using GNSS signal has been extensively studied,particularly the one using a priori attitude information replacing the code measurements to enhance the successful rate for ambiguity resolution.However,there exists a key limitation that this method relies on considerable Monte Carlo sampling particles to construct the pdf of ambiguities,resulting in significant computational burdens.To address this limitation,this paper provides a rapid single-epoch GNSS attitude determination method based on a priori attitude information.It utilizes a second-order Taylor expansion to analytically estimate the covariance of the baseline conditioned on a priori attitude information.This is followed by deriving the float solution and covariance of ambiguities,which are then processed using the standard LAMBDA method for integer ambiguity resolution.Experimental results demonstrate that our method is both efficient and accurate,significantly reducing computational costs compared to previous methods,thereby enhancing its applicability for GNSS-based attitude determination.
基金supported in part by the National Key Research and Development Program of China(Nos.2020YFA0711200,2022YFB4701301)in part by the Defense Industrial Technology Development Program,China(No.JCKY2021601B016)+1 种基金in part by the Fundamental Research Funds for the Central Universities,China(No.YWF-23-JC-07)in part by the National Natural Science Foundation of China(No.62425302)。
文摘Nighttime navigation faces challenges from limited data and interference,especially when satellite signals are unavailable.Leveraging lunar polarized light,polarization navigation offers a promising solution for nighttime autonomous navigation.Current algorithms,however,are limited by the requirement for known horizontal attitudes,restricting applications.This study introduces an autonomous 3-D attitude determination method to overcome this limitation.Our approach utilizes the Angle of Polarization(AOP)at night to extract neutral points from the AOP pattern.This allows for the calculation of polarization meridian plane information for attitude determination.Subsequently,we present an optimized Polarization TRIAD(Pol-TRIAD)algorithm to acquire the 3-D attitude.The proposed method outperforms the existing approaches in outdoor experiments by achieving lower Root Mean Square Error(RMSE).For one baseline attitude,it improves pitch by 31.7%,roll by 21.7%,and yaw by 2.6%,while for the attitude with a larger tilt angle,the improvements are 64.4%,30.4%,and 9.1%,respectively.
文摘Navigation satellites generally use satellite-ground and inter-satellite observation data for precise orbit determination.In orbit determination,the satellite position is often referenced to the satellite’s centroid,while the observational measurements are referenced to the satellite’s antenna phase center.The deviation between the satellite’s centroid and the antenna phase center forms the satellite antenna phase center error,which affects the precision of orbit determination.This paper takes a global navigation satellite system(GNSS)MEO satellite as an example and analyzes the actual situation of the satellite antenna phase center deviation and phase center variation based on the ground calibration data of the in-orbit satellite antenna phase center and the satellite’s in-orbit working status.The analysis shows that the antenna phase center variation caused by the satellite’s in-orbit operation is only at the centimeter level,which has a limited impact on orbit determination accuracy.The main source of precise orbit determination error is the satellite antenna phase center deviation,which can be corrected using ground calibration data.
基金supported by the National Natural Science Foundation of China(No.22090041)the Program for Guangdong Introducing Innovative and Entrepreneurial Teams(No.2017ZT07C069)+1 种基金the Guangdong Basic and Applied Basic Research Foundation(No.2022B1515120014)the Natural Science Foundation of Zhejiang Province(No.LQ21A040010).
文摘The exploratory synthesis and structural characterization of twodimensional(2D)honeycomb structured Ru-based compounds are key focuses in inorganic materials research,due to the various exotic electronic states arising from the interplay of electron correlations and spinorbit coupling.Among these compounds,α-RuCl_(3) and RuBr_(3) are considered as the most promising candidates for quantum spin liquid(QSL)materials[1–3].As a homolog,α-RuI3 has attracted significant interest,but it still remains relatively unexplored.Recently,it was synthesized by high-temperature and high-pressure solid-state reaction,but reported to be different crystal structures by independent groups.Ni et al.and Nawa et al.considerα-RuI3 to be R-3(3R)and P-31c(2H)space group,respectively[4,5].Both structures have typical 2D characteristics,in which the edge-sharing RuI6 octahedra form honeycomb layers stacked along the c-axis.The primary difference lies in that the honeycomb layers stack in ABCABC mode in the 3R phase,while in ABAB mode in the 2H phase(Fig.S1).Yang et al.discussed the stability of 3R and 2H polymorphs in terms of the total energies and dynamics,finding both structures are stable.However,the total energy of the 2H phase is slightly higher,2.58 meV than that of the 3R analog[6].When it comes to the conductivity behaviour,α-RuCl3 andα-RuBr_(3) are semiconductors as normally observed in QSL materials.In contrast,α-RuI_(3) exhibits metallic response.In 2D materials,the band structure may be drastically modified by altering the stacking order[7].Hence,determining the crystal structure ofα-RuI_(3) is urgently required,which is a key step in comprehensive and in-depth analysis of its physical properties.
基金supported by Jiangsu Province Fron-tier Leading Technology Basic Research Project(BK20222013)partly supported by National Natural Science Foundation of China(No.62101251)+1 种基金Fundamental Research Funds for the Central Universities(No.NS20240240)partly supported by Post-graduate Research&Practice Innovation Program of NUAA(No.016001)。
文摘The deployment of the low earth orbit(LEO)satellites provides a large number of signals of opportunity(SOPs),unmanned aerial vehicle(UAV)positioning and navigation via LEO-SOPs have re-ceived much attention.Current research is focused on Doppler positioning techniques,which require the collaboration of multiple satellites(≥3).However,the dynamic changes of LEO satellites weaken the generalization ability of Doppler positioning.In this paper,a direct position determination(DPD)method with uniform circular array(UCA)is proposed for UAV positioning from the perspective of the spatial spectrum estimation of LEO-SOPs.The proposed method employs the orthogonality between the signal and noise subspaces of the covariance matrix of the different received SOPs to establish the cost function for UAV’s coordinate.Instead of the multiple dimen-sional search,a root mean square propagation(RM-SProp)gradient optimizer with an adaptive learning rate is developed to find the coordinate of UAV.The effectiveness and robustness of the proposed method are verified using numerical data generated from the systems tool kit(STK).
