Cryptocurrency,a booming decentralised asset designed based on the blockchain architecture,is particularly important to the market at the present time by studying the volatility risk of cryptocurrencies.In this paper,...Cryptocurrency,a booming decentralised asset designed based on the blockchain architecture,is particularly important to the market at the present time by studying the volatility risk of cryptocurrencies.In this paper,we empirically analyse the volatility risk of cryptocurrencies through quantitative analysis models,comprehensively using the Markov state transition GARCH model with skewed distribution(Skew-MSGARCH)and the autoregressive conditional volatility density ARJI model introducing the Poisson jump factor,and selecting the earliest developed and the most mature currency price volatility daily return series,to deeply explore the volatility risk of digital cryptocurrencies.risk.Finally,it can be seen through in-depth analyses that the expectation factor and information inducement are the main reasons leading to the exacerbation of the volatility risk of digital cryptocurrencies.It is recommended that this situation be optimised and improved in terms of the value function of digital cryptocurrencies themselves and the implementation of systematic risk management and regulatory innovation.As an important component of the digital economy,blockchain technology can effectively regulate and improve the volatility of digital cryptocurrencies under macroeconomic policies,thereby maintaining the security and stability of emerging financial markets.展开更多
Objective To quantitatively analyze the policy of centralized drug procurement centralized drug procurement in order to provide reference for the subsequent policy formulation and improvement.Methods Text mining metho...Objective To quantitatively analyze the policy of centralized drug procurement centralized drug procurement in order to provide reference for the subsequent policy formulation and improvement.Methods Text mining method was used to process 15 centralized drugs procurement policies issued at the national level during 2015-2022,and a PMC index evaluation model of centralized drug procurement policies was established.Then,15 centralized drug procurement policies were quantitatively analyzed from the overall and comparative perspective through an evaluation model.Results and Conclusion The average PMC index of 15 centralized drug procurement policies was 6.95,which was acceptable on the whole.Among them,eight were excellent and seven were acceptable.As to the first-order variables,the centralized drugs procurement policy still lacks incentives and constraints.The comparative results show that there are differences in the content and structure of policies,but they are strongly related to each other.Chinese centralized drug procurement policy has been basically formed,which is closely related to medical insurance and medical policies.However,it is still necessary to pay attention to the structure of the policy to ensure the elaboration of the policy content.展开更多
Optimization and simplification of optical systems represent a milestone in advancing the development of handheld and portable laser-induced breakdown spectroscopy(LIBS)systems towards smaller,more integrated forms.Th...Optimization and simplification of optical systems represent a milestone in advancing the development of handheld and portable laser-induced breakdown spectroscopy(LIBS)systems towards smaller,more integrated forms.This research,for the first time,conducted a comprehensive optimization design and comparative analysis of three compact LIBS system optical paths:the paraxial optical path(OP),the off-axis OP,and the reflective OP.The differences in spectral intensity and stability among these paths were revealed,providing a scientific basis for selecting the optimal OP for LIBS systems.The research found that the paraxial OP excels in spectral performance and quantitative analysis accuracy,making it the preferred choice for compact LIBS systems.Specifically,the paraxial OP significantly enhances spectral intensity,achieving a 6 times improvement over the off-axis OP and an even more remarkable 150 times increase compared to the reflective OP,greatly enhancing detection sensitivity.Additionally,the relative standard deviation,spectral stability index,maintains a consistently low level,ranging from 10.9%to 13.4%,significantly outperforming the other two OPs and ensuring the reliability of analytical results.In the field of quantitative analysis,the paraxial OP also demonstrates higher accuracy,precision,and sensitivity,comparing to other OPs.The quantitative analysis models for Si,Cu,and Ti elements exhibit excellent fitting,providing users with high-quality quantitative analysis results that are of great significance for applications in material science,environmental monitoring,industrial inspection,and other fields.In summary,this study not only confirms the enormous application potential of the paraxial OP in compact LIBS systems but also provides valuable practical experience and theoretical support for the miniaturization and integration of LIBS systems.Looking ahead,with continuous technological advancements,the design of the paraxial OP is expected to further propel the widespread adoption of LIBS technology in portable,on-site detection applications.展开更多
3-Nitro-1,2,4-triazol-5-one(NTO)is a typical high-energy,low-sensitivity explosive,and accurate concentration monitoring is critical for crystallization process control.In this study,a high-precision quantitative anal...3-Nitro-1,2,4-triazol-5-one(NTO)is a typical high-energy,low-sensitivity explosive,and accurate concentration monitoring is critical for crystallization process control.In this study,a high-precision quantitative analytical model for NTO concentration in ethanol solutions was developed by integrating real-time ATR-FTIR spectroscopy with chemometric and machine learning techniques.Dynamic spectral data were obtained by designing multi-concentration gradient heating-cooling cycle experiments,abnormal samples were eliminated using the isolation forest algorithm,and the effects of various preprocessing methods on model performance were systematically evaluated.The results show that partial least squares regression(PLSR)exhibits superior generalization ability compared to other models.Vibrational bands corresponding to C=O and–NO_(2)were identified as key predictors for concentration estimation.This work provides an efficient and reliable solution for real-time concentration monitoring during NTO crystallization and holds significant potential for process analytical applications in energetic material manufacturing.展开更多
Huang-Lian-Jie-Du-Decoction （HLJDD） has been widely used for the treatment of Alzheimer＇s disease （AD） in clinic. However, the relationship between its chemical profile and neuroprotective bioactivity was not cle...Huang-Lian-Jie-Du-Decoction （HLJDD） has been widely used for the treatment of Alzheimer＇s disease （AD） in clinic. However, the relationship between its chemical profile and neuroprotective bioactivity was not clearly clarified yet. In present study, the water extract of HLJDD and subsequent three polarity fractions divided by different reagents were investigated. A total of 17 chromatographic peaks were confirmed by comparison with standards and their UV, MS spectra. Among them, 11 major compounds were determined by HPLC-DAD method with good linear regression relationship （r2, 0.9994-0.9999）, precisions （inter-day precision RSD, 0.79%-1.07%; intra-day precision RSD, 1.59%-2.10%）, repeatability （RSD, 1.66%-3.67%）, stability （RSD, 1.26%-4.77%） and recovery （95.24%-105.41%, RSD, 0.29%-2.69%）. Furthermore, PC12 cells and primary neurons cells were used for the neuroprotective effective assessment of aforementioned four samples from HLJDD. 3＂he total aqueous extract and n-butanol extract of HLJDD presented more significant effects than the other two parts. According to their quality and quantity determination results, iridoids and alkaloids have a positive correlation with the neuroprotective effectiveness of HLJDD.展开更多
A reliable and accurate HPLC/UV method was developed for the quantitative determination of astragaloside IV in ＇Huang-Qi-Si-Wu＇ Capsules, a widely used prescription of traditional Chinese medicines （TCM）. The chro...A reliable and accurate HPLC/UV method was developed for the quantitative determination of astragaloside IV in ＇Huang-Qi-Si-Wu＇ Capsules, a widely used prescription of traditional Chinese medicines （TCM）. The chromatographic separation conditions employed for HPLC/UV were optimized using a Hypersil-ODS column （250 mm^4.6 mm, 5.0 pm） with isocratic elution. Acetonitrile-water （32：68, v/v） were used as the mobile phase pumped at a flow rate of 1.0 mL/min and a detection wavelength at 203 nm was used. The method was fully validated with respect to linearity, precision, accuracy, specificity and robustness. The validated method was applied successfully to the quantification of astragaloside IV in the extract of ＇Huang-Qi- Si-Wu＇ Capsules from different production batches. The results indicate that the established HPLC/UV method is suitable for the quantitative analysis and quality control of ＇Huang-Qi-Si-Wu＇ Capsules and other related botanical drugs.展开更多
A combined method of high performance liquid chromatograph-elecrtrospray-ionization mass spectrometer（HPLC-ESI-MS/MS） coupled with a photodiode array detector（HPLC-DAD） and principal component analysis（PCA） was ...A combined method of high performance liquid chromatograph-elecrtrospray-ionization mass spectrometer（HPLC-ESI-MS/MS） coupled with a photodiode array detector（HPLC-DAD） and principal component analysis（PCA） was applied to the qualitative and quantitative analyses of alkaloids in Cortex Phellodendri（CP） samples, and to the differentiation of two species of CP, Cortex Phellodendri Chinensis（CPC） and Cortex Phellodendri Amurensis（CPA）. Twenty-two peaks appeared in the HPLC-MS base peak chromatogram of CP detected by the HPLC-ESI-MS/MS analysis, and the alkaloids were identified according to the MSn data, the known MS fragmentation rules and the literature data. Five alkaloids including berberine, palmatine, jatrorrhizine, phellodendrine and magnoflorine were simultaneously determinated by the HPLC-DAD. Berberine was the primary component in all CP samples, and the contents of berberine and palmatine were exploited to be two critical parameters for effective discrimination between the two species of CP. The average content of berberine in CPC（58.75 mg/g） was higher than that in CPA（9.16 mg/g）, while the content of palmatine was less, only 0.25 mg/g in CPC and 4.19 mg/g in CPA. With the use of PCA, samples datasets were separated successfully into two different clusters corresponding to the two species, and berberine, pahnatine, phellodendrine and magnoflorine contribute most to the above mentioned calssifying . The proposed method oroved to be a useful tool in the aualitv control of Chinese herbal medicines.展开更多
AIM: To study liver cell apoptosis caused by the toxicity of selenium and observe the alteration of choline compounds using in vitro 9.4T high resolution magnetic resonance spectroscopy. METHODS: Twenty male Wistar ra...AIM: To study liver cell apoptosis caused by the toxicity of selenium and observe the alteration of choline compounds using in vitro 9.4T high resolution magnetic resonance spectroscopy. METHODS: Twenty male Wistar rats were randomly divided into two groups. The rats in the treatment group were intraperitoneally injected with sodium selenite and the control group with distilled water. All rats were sacrifi ced and the livers were dissected. 1H-MRS data were collected using in vitro 9.4T high resolution magnetic resonance spectrometer. Spectra were processed using XWINNMR and MestRe-c 4.3. HE and TUNEL staining was employed to detect and confi rm the change of liver cells. RESULTS: Good 1H-MR spectra of perchloric acid extract from liver tissue of rats were obtained. The conventional metabolites were detected and assigned. Concentrations of different ingredient choline compounds in treatment group vs control group were as follows: total choline compounds,5.08 ± 0.97 mmol/L vs 3.81 ± 1.16 mmol/L (P = 0.05); and free choline,1.07 ± 0.23 mmol/L vs 0.65 ± 0.20 mmol/L (P = 0.00). However,there was no statistical signif icance between the two groups. The hepatic sinus and cellular structure of hepatic cells in treatmentgroup were abnormal. Apoptosis of hepatic cells was confi rmed by TUNEL assay. CONCLUSION: High dose selenium compounds can cause the rat liver lesion and induce cell apoptosis in vivo. High resolution 1H-MRS in vitro can detect diversified metabolism. The changing trend for different ingredient of choline compounds is not completely the same at early period of apoptosis.展开更多
Several studies have demonstrated that soil reflectance decreases with increasing soil moisture content, or increases when the soil moisture reaches a certain content; however, there are few analyses on the quantitati...Several studies have demonstrated that soil reflectance decreases with increasing soil moisture content, or increases when the soil moisture reaches a certain content; however, there are few analyses on the quantitative relationship between soil reflectance and its moisture, especially in the case of black soils in northeast China. A new moisture adjusting method was developed to obtain soil reflectance with a smaller moisture interval to describe the quantitative relationship between soil reflectance and moisture. For the soil samples with moisture contents ranging from air-dry to saturated, the changes in soil reflectance with soil moisture can be depicted using a cubic equation. Both moisture threshold (MT) and moisture inflexion (MI) of soil reflectance can also be determined by the equation. When the moisture range was smaller than MT, soil reflectance can be simulated with a linear model. However, for samples with different soil organic matter (OM), the parameters of the linear model varied regularly with the OM content. Based on their relationship, the soil moisture can be estimated from soil reflectance in the black soil region.展开更多
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
Due to the disturbances arising from the coherence of reflected waves and from echo noise,problems such as limitations,instability and poor accuracy exist with the current quantitative analysis methods.According to th...Due to the disturbances arising from the coherence of reflected waves and from echo noise,problems such as limitations,instability and poor accuracy exist with the current quantitative analysis methods.According to the intrinsic features of GPR signals and wavelet time–frequency analysis,an optimal wavelet basis named GPR3.3 wavelet is constructed via an improved biorthogonal wavelet construction method to quantitatively analyse the GPR signal.A new quantitative analysis method based on the biorthogonal wavelet(the QAGBW method)is proposed and applied in the analysis of analogue and measured signals.The results show that compared with the Bayesian frequency-domain blind deconvolution and with existing wavelet bases,the QAGBW method based on optimal wavelet can limit the disturbance from factors such as the coherence of reflected waves and echo noise,improve the quantitative analytical precision of the GPR signal,and match the minimum thickness for quantitative analysis with the vertical resolution of GPR detection.展开更多
In the spectral analysis of laser-induced breakdown spectroscopy,abundant characteristic spectral lines and severe interference information exist simultaneously in the original spectral data.Here,a feature selection m...In the spectral analysis of laser-induced breakdown spectroscopy,abundant characteristic spectral lines and severe interference information exist simultaneously in the original spectral data.Here,a feature selection method called recursive feature elimination based on ridge regression(Ridge-RFE)for the original spectral data is recommended to make full use of the valid information of spectra.In the Ridge-RFE method,the absolute value of the ridge regression coefficient was used as a criterion to screen spectral characteristic,the feature with the absolute value of minimum weight in the input subset features was removed by recursive feature elimination(RFE),and the selected features were used as inputs of the partial least squares regression(PLS)model.The Ridge-RFE method based PLS model was used to measure the Fe,Si,Mg,Cu,Zn and Mn for 51 aluminum alloy samples,and the results showed that the root mean square error of prediction decreased greatly compared to the PLS model with full spectrum as input.The overall results demonstrate that the Ridge-RFE method is more efficient to extract the redundant features,make PLS model for better quantitative analysis results and improve model generalization ability.展开更多
Quantitative analysis of the impact factors in energy-related CO2 emissions serves as an important guide for reducing carbon emissions and building an environmentally-friendly society. This paper aims to use LMDI meth...Quantitative analysis of the impact factors in energy-related CO2 emissions serves as an important guide for reducing carbon emissions and building an environmentally-friendly society. This paper aims to use LMDI method and a modified STIRPAT model to research the conventional energy-related CO_2 emissions in Kazakhstan after the collapse of the Soviet Union. The results show that the trajectory of CO2 emissions displayed U-shaped curve from 1992 to 2013. Based on the extended Kaya identity and additive LMDI method, we decomposed total CO2 emissions into four influencing factors. Of those, the economic active effect is the most influential factor driving CO2 emissions, which produced 110.86 Mt CO2 emissions, with a contribution rate of 43.92%. The second driving factor is the population effect, which led to 11.87 Mt CO2 emissions with a contribution rate of 4.7%. On the contrary, the energy intensity effect is the most inhibiting factor, which caused –110.90 Mt CO2 emissions with a contribution rate of –43.94%, followed by the energy carbon structure effect resulting in –18.76 Mt CO2 emissions with a contribution rate of –7.43%. In order to provide an in-depth examination of the change response between energy-related CO2 emissions and each impact factor, we construct a modified STIRPAT model based on ridge regression estimation. The results indicate that for every 1% increase in population size, economic activity, energy intensity and energy carbon structure, there is a subsequent increase in CO_2 emissions of 3.13%, 0.41%, 0.30% and 0.63%, respectively.展开更多
The granulation of blast furnace slag （BFS） with water quenching treatment has some disadvantages, such as high water consumption and difficulty for recovery heat. So developing a new dry granulation technique to tr...The granulation of blast furnace slag （BFS） with water quenching treatment has some disadvantages, such as high water consumption and difficulty for recovery heat. So developing a new dry granulation technique to treat BFS is very important. The applicability of BFS directly depends on the content of non-crystalline solids in the slag after treatment. So it is of theoretical and practical significance to analyze the content of non-crystalline solids in the slag quantitatively and simply. Metallographical test is mainly adopted to quantify the non-crystalline in BFS so far with the shortages such as complex sample, difficult determination, ect. The diffraction intensity of non-crystalline is proportionate to the content of non-crystalline in BFS, ~ray diffraction method was adopted to quantify the noncrystalline and the crystalline solids in BFS. The quantitative coefficient between the crystalline and the non-crystalline solids of BFS is 0.70 of BFS whose main composition （mass percent, %） is： CaO 38.2, SiO2 35.7, Al2Oa 16.3, and MgO 8.3. The relative error of X-ray diffractometer for quantitatively analyzing non-crystalline content of BFS is less than 1%.展开更多
Using the theory and method of the ecological footprint, and combining the changes of regional land use, resource environment, population, society and economy, this paper calculated the ecological footprint, ecologica...Using the theory and method of the ecological footprint, and combining the changes of regional land use, resource environment, population, society and economy, this paper calculated the ecological footprint, ecological carrying capacity and ecological surplus/loss in 1986-2002 on the Loess Plateau in northern Shaanxi Province. What is more, this paper has put forward the concept of ecological pressure index, set up ecological pressure index models, and ecological security grading systems, and the prediction models of different ecological footprints, ecological carrying capacity, ecological surplus and ecological safety change, and also has assessed the ecological footprint demands of 10,000 yuan GDE The results of this study are as follows： （1） the ecological carrying capacity in northern Shaanxi shows a decreasing trend, the difference of reducing range is the fastest; （2） the ecological footprint appears an increasing trend; （3） ecological pressure index rose to 0.91 from 0.44 during 1986-2002 on the Loess Plateau of northern Shaanxi with an increase of 47%; and （4） the ecological security in the study area is in a critical state, and the ecological oressure index has been increasing rapidlv.展开更多
Ecological footprint （EF） has attracted much attention internationally as a potential indicator for sustainable development. In China, EF has also gained recognition in related fields and disciplines. Moreover, some...Ecological footprint （EF） has attracted much attention internationally as a potential indicator for sustainable development. In China, EF has also gained recognition in related fields and disciplines. Moreover, some scholars in these fields have proposed alternative methods to calculate EF and have made some progress. This paper, therefore, begins with the introduction and development of EF in China. However, the established methods of EF calculation hold some limitations, such as indicator variance and result abnormality. In order to resolve those problems, the authors make a further modification considering the demand of EF as a comprehensive indicator： 1） More accurate analysis has been done to divide EF into several parts： imported EF, exported EF, and producible EF, which is the solution to the problem of abnormality in original EF results and can explain abnormal phenomena reasonably. 2） Considering the actual situa- tion of Shanghai, emended equivalence factor is brought forward and a matrix is formed with equivalence factors. The measure can reduce the deviation between the fact and the results. 3） The calculation compares local yield with global average yield to analyze the effects of yields. And based on local yields in different years, the results are more accurate. Finally, the calculation method is applied to calculating EF of Shanghai from 1980 to 2003, and the subsequent detailed analysis is presented. Available data and results suggest a statistically significant correlation coefficient between EF and GDP, population density and urbaniTation level. Through analyzing the process of calculating EF and its results, it can be seen that EF, as a macro-indicator, can not exactly indicate whether development within a region can meet the re- quests of sustainable development, which can be explained by the fact that the result of EF is impacted greatly by sub- jective factors including national policy,available technology, population, etc. Nevertheless, EF can demonstrate, at least to some degree, the regional status in terms of resources and energy consumption, as well as developmental potential. The calculation of EF, therefore, deserves further research to achieve more far-reaching significance in application.展开更多
In this paper, a double artificial neural network （DANN） algorithm was used to parse near infrared （NIR） reflectance spectrum of Cofrel medicines. The contents of benproperine phosphate, which is the effective ing...In this paper, a double artificial neural network （DANN） algorithm was used to parse near infrared （NIR） reflectance spectrum of Cofrel medicines. The contents of benproperine phosphate, which is the effective ingredient in Cofrel medicines, were accurately nondestructive quantitatively predicted. Compared the results with those of HPLC, the relative errors （RE %） were less than 0.18%. The analytical results could be applied to qualitative control of Cofrel medicines.展开更多
Tokamak exhaust is an important part of the deuterium-tritium fuel cycle system in fusion reactions.In this work,we present a laser-induced breakdown spectroscopy(LIBS)-based method to monitor the gas compositions fro...Tokamak exhaust is an important part of the deuterium-tritium fuel cycle system in fusion reactions.In this work,we present a laser-induced breakdown spectroscopy(LIBS)-based method to monitor the gas compositions from the exhaust system in the tokamak device.Helium(He),a main impurity in the exhaust gas,was mixed with hydrogen(H_(2))in different ratios through a self-designed gas distribution system,and sealed into a measurement chamber as a standard specimen.A 532 nm wavelength laser pulse with an output power of 100 mJ was used for plasma excitation.The time-resolved LIBS is used to study the time evolution characteristics of the signal strength,signal-to-background ratio(SBR),signal-to-noise ratio(SNR)and relative standard deviation(RSD)of the helium and hydrogen characteristic lines.The Boltzmann twoline method was employed to estimate the plasma temperature of laser-induced plasma(LIP).The Stark-broadened profile of He I 587.56 nm was exploited to measure the electron density.From these studies,an appropriate time was determined in which the low RSD%was consistent with the high signal-to-noise ratio.The He I 587.56 nm and Hαemission lines with good signalto-noise ratio were extracted from the spectrum and used in the external standard method and internal standard method for quantitative analysis.The test results for mixed gas showed that the average relative error of prediction was less than 11.15%,demonstrating the great potential of LIBS in detecting impurities in plasma exhaust gas.展开更多
Mercury ions are highly toxic and can accumulate along food chains in water,soil,crops and animals.Effective detection of mercury ions in various media is of great significance for maintaining the ecological environme...Mercury ions are highly toxic and can accumulate along food chains in water,soil,crops and animals.Effective detection of mercury ions in various media is of great significance for maintaining the ecological environment and protecting people's health.In this work,a mercury ions specific fluorescent probe was developed by a simple one-step reaction of commercial substrates of 4-chloro-7-nitro-2,1,3-benzoxadiazole and 1-(2-aminoethyl)-4-methylpiperazine.Investigation on sensing behavior showed that this probe had high sensitivity and selectivity towards mercury ions.Furthermore,this probe could be used as a tool to track the level of mercury ions in living system.In living cells,the probe with green emission emitted a bright red fluorescence when it was bound to mercury ions.In Arabidopsis thaliana,similar red emission could be detected from the root tip and stalk when A.thaliana was grown in culture medium containing mercury ions.The imaging in zebrafish showed that mercury ions were mainly concentrated in the stomach and head of zebrafish.Especially,this probe could be applied in quantitative analysis of mercury ions in tap water,green tea,sea shrimp and soil.This work provided a practical tool for the detection of mercury ions in living systems and quantitative analysis in real samples.展开更多
Surface-enhanced Raman scattering(SERS)is a powerful spectroscopic tool in quantitative analysis of molecules,where the substrate plays a critical role in determining the detection performance.Herein,a silver nanocube...Surface-enhanced Raman scattering(SERS)is a powerful spectroscopic tool in quantitative analysis of molecules,where the substrate plays a critical role in determining the detection performance.Herein,a silver nanocubes/polyelectrolyte/gold film sandwich structure was prepared as a reproducible,highperformance SERS substrate by the wate r/oil inte rfacial assembly method.In addition to the hot spots on the nanocubes surface,the edge-to-edge interspace of the Ag nanocubes led to marked enhancement of the SERS intensity,with a limit of detection of 10~(11)mol/L and limit of quantitation of 10~(10)mol/L for crystal violet.When rhodamine 6 G and crystal violet were co-adsorbed on the Ag nanocube surfaces,the characteristic SERS peaks of the two molecules remained well resolved and separated,and the peak intensities varied with the respective concentration,which could be exploited for concurrent detection of dual molecules.Results from this work indicate that organized ensembles of Ag nanocubes can serve as effective SERS substrate can for sensitive analysis for complex molecular systems.展开更多
文摘Cryptocurrency,a booming decentralised asset designed based on the blockchain architecture,is particularly important to the market at the present time by studying the volatility risk of cryptocurrencies.In this paper,we empirically analyse the volatility risk of cryptocurrencies through quantitative analysis models,comprehensively using the Markov state transition GARCH model with skewed distribution(Skew-MSGARCH)and the autoregressive conditional volatility density ARJI model introducing the Poisson jump factor,and selecting the earliest developed and the most mature currency price volatility daily return series,to deeply explore the volatility risk of digital cryptocurrencies.risk.Finally,it can be seen through in-depth analyses that the expectation factor and information inducement are the main reasons leading to the exacerbation of the volatility risk of digital cryptocurrencies.It is recommended that this situation be optimised and improved in terms of the value function of digital cryptocurrencies themselves and the implementation of systematic risk management and regulatory innovation.As an important component of the digital economy,blockchain technology can effectively regulate and improve the volatility of digital cryptocurrencies under macroeconomic policies,thereby maintaining the security and stability of emerging financial markets.
文摘Objective To quantitatively analyze the policy of centralized drug procurement centralized drug procurement in order to provide reference for the subsequent policy formulation and improvement.Methods Text mining method was used to process 15 centralized drugs procurement policies issued at the national level during 2015-2022,and a PMC index evaluation model of centralized drug procurement policies was established.Then,15 centralized drug procurement policies were quantitatively analyzed from the overall and comparative perspective through an evaluation model.Results and Conclusion The average PMC index of 15 centralized drug procurement policies was 6.95,which was acceptable on the whole.Among them,eight were excellent and seven were acceptable.As to the first-order variables,the centralized drugs procurement policy still lacks incentives and constraints.The comparative results show that there are differences in the content and structure of policies,but they are strongly related to each other.Chinese centralized drug procurement policy has been basically formed,which is closely related to medical insurance and medical policies.However,it is still necessary to pay attention to the structure of the policy to ensure the elaboration of the policy content.
基金financially supported by National Natural Science Foundation of China (Nos.62305392 and 62305123)Independent Research and Development Project of Naval Engineering University (No.2023504050)the Nursery Plan Project of Navel University of Engineering (2022)。
文摘Optimization and simplification of optical systems represent a milestone in advancing the development of handheld and portable laser-induced breakdown spectroscopy(LIBS)systems towards smaller,more integrated forms.This research,for the first time,conducted a comprehensive optimization design and comparative analysis of three compact LIBS system optical paths:the paraxial optical path(OP),the off-axis OP,and the reflective OP.The differences in spectral intensity and stability among these paths were revealed,providing a scientific basis for selecting the optimal OP for LIBS systems.The research found that the paraxial OP excels in spectral performance and quantitative analysis accuracy,making it the preferred choice for compact LIBS systems.Specifically,the paraxial OP significantly enhances spectral intensity,achieving a 6 times improvement over the off-axis OP and an even more remarkable 150 times increase compared to the reflective OP,greatly enhancing detection sensitivity.Additionally,the relative standard deviation,spectral stability index,maintains a consistently low level,ranging from 10.9%to 13.4%,significantly outperforming the other two OPs and ensuring the reliability of analytical results.In the field of quantitative analysis,the paraxial OP also demonstrates higher accuracy,precision,and sensitivity,comparing to other OPs.The quantitative analysis models for Si,Cu,and Ti elements exhibit excellent fitting,providing users with high-quality quantitative analysis results that are of great significance for applications in material science,environmental monitoring,industrial inspection,and other fields.In summary,this study not only confirms the enormous application potential of the paraxial OP in compact LIBS systems but also provides valuable practical experience and theoretical support for the miniaturization and integration of LIBS systems.Looking ahead,with continuous technological advancements,the design of the paraxial OP is expected to further propel the widespread adoption of LIBS technology in portable,on-site detection applications.
基金supported by the Aeronautical Science Foundation of China(Grant No.20230018072011)。
文摘3-Nitro-1,2,4-triazol-5-one(NTO)is a typical high-energy,low-sensitivity explosive,and accurate concentration monitoring is critical for crystallization process control.In this study,a high-precision quantitative analytical model for NTO concentration in ethanol solutions was developed by integrating real-time ATR-FTIR spectroscopy with chemometric and machine learning techniques.Dynamic spectral data were obtained by designing multi-concentration gradient heating-cooling cycle experiments,abnormal samples were eliminated using the isolation forest algorithm,and the effects of various preprocessing methods on model performance were systematically evaluated.The results show that partial least squares regression(PLSR)exhibits superior generalization ability compared to other models.Vibrational bands corresponding to C=O and–NO_(2)were identified as key predictors for concentration estimation.This work provides an efficient and reliable solution for real-time concentration monitoring during NTO crystallization and holds significant potential for process analytical applications in energetic material manufacturing.
基金Key Projects in the National Science & Technology Pillar Program during the 11thFive-Year Plan Period (Grant No.2008BAI51B02)National Natural Science Fund Project of China (Grant No. 81202904)
文摘Huang-Lian-Jie-Du-Decoction （HLJDD） has been widely used for the treatment of Alzheimer＇s disease （AD） in clinic. However, the relationship between its chemical profile and neuroprotective bioactivity was not clearly clarified yet. In present study, the water extract of HLJDD and subsequent three polarity fractions divided by different reagents were investigated. A total of 17 chromatographic peaks were confirmed by comparison with standards and their UV, MS spectra. Among them, 11 major compounds were determined by HPLC-DAD method with good linear regression relationship （r2, 0.9994-0.9999）, precisions （inter-day precision RSD, 0.79%-1.07%; intra-day precision RSD, 1.59%-2.10%）, repeatability （RSD, 1.66%-3.67%）, stability （RSD, 1.26%-4.77%） and recovery （95.24%-105.41%, RSD, 0.29%-2.69%）. Furthermore, PC12 cells and primary neurons cells were used for the neuroprotective effective assessment of aforementioned four samples from HLJDD. 3＂he total aqueous extract and n-butanol extract of HLJDD presented more significant effects than the other two parts. According to their quality and quantity determination results, iridoids and alkaloids have a positive correlation with the neuroprotective effectiveness of HLJDD.
基金Scientific and Technological Innovation Project Foundation of Shanxi,China(Grant No.20090321099)
文摘A reliable and accurate HPLC/UV method was developed for the quantitative determination of astragaloside IV in ＇Huang-Qi-Si-Wu＇ Capsules, a widely used prescription of traditional Chinese medicines （TCM）. The chromatographic separation conditions employed for HPLC/UV were optimized using a Hypersil-ODS column （250 mm^4.6 mm, 5.0 pm） with isocratic elution. Acetonitrile-water （32：68, v/v） were used as the mobile phase pumped at a flow rate of 1.0 mL/min and a detection wavelength at 203 nm was used. The method was fully validated with respect to linearity, precision, accuracy, specificity and robustness. The validated method was applied successfully to the quantification of astragaloside IV in the extract of ＇Huang-Qi- Si-Wu＇ Capsules from different production batches. The results indicate that the established HPLC/UV method is suitable for the quantitative analysis and quality control of ＇Huang-Qi-Si-Wu＇ Capsules and other related botanical drugs.
基金Supported by the National Natural Science Foundation of China(No30725045)the Foundation of Eleventh Five-Year-Plan of China(No2008ZX09202-002)+1 种基金the Shanghai Leading Academic Discipline Project, China(NoB906)the Scientific Foundation of Shanghai City, China(No07DZ19702)
文摘A combined method of high performance liquid chromatograph-elecrtrospray-ionization mass spectrometer（HPLC-ESI-MS/MS） coupled with a photodiode array detector（HPLC-DAD） and principal component analysis（PCA） was applied to the qualitative and quantitative analyses of alkaloids in Cortex Phellodendri（CP） samples, and to the differentiation of two species of CP, Cortex Phellodendri Chinensis（CPC） and Cortex Phellodendri Amurensis（CPA）. Twenty-two peaks appeared in the HPLC-MS base peak chromatogram of CP detected by the HPLC-ESI-MS/MS analysis, and the alkaloids were identified according to the MSn data, the known MS fragmentation rules and the literature data. Five alkaloids including berberine, palmatine, jatrorrhizine, phellodendrine and magnoflorine were simultaneously determinated by the HPLC-DAD. Berberine was the primary component in all CP samples, and the contents of berberine and palmatine were exploited to be two critical parameters for effective discrimination between the two species of CP. The average content of berberine in CPC（58.75 mg/g） was higher than that in CPA（9.16 mg/g）, while the content of palmatine was less, only 0.25 mg/g in CPC and 4.19 mg/g in CPA. With the use of PCA, samples datasets were separated successfully into two different clusters corresponding to the two species, and berberine, pahnatine, phellodendrine and magnoflorine contribute most to the above mentioned calssifying . The proposed method oroved to be a useful tool in the aualitv control of Chinese herbal medicines.
基金The National Natural Science Foundation of China,No.30570480
文摘AIM: To study liver cell apoptosis caused by the toxicity of selenium and observe the alteration of choline compounds using in vitro 9.4T high resolution magnetic resonance spectroscopy. METHODS: Twenty male Wistar rats were randomly divided into two groups. The rats in the treatment group were intraperitoneally injected with sodium selenite and the control group with distilled water. All rats were sacrifi ced and the livers were dissected. 1H-MRS data were collected using in vitro 9.4T high resolution magnetic resonance spectrometer. Spectra were processed using XWINNMR and MestRe-c 4.3. HE and TUNEL staining was employed to detect and confi rm the change of liver cells. RESULTS: Good 1H-MR spectra of perchloric acid extract from liver tissue of rats were obtained. The conventional metabolites were detected and assigned. Concentrations of different ingredient choline compounds in treatment group vs control group were as follows: total choline compounds,5.08 ± 0.97 mmol/L vs 3.81 ± 1.16 mmol/L (P = 0.05); and free choline,1.07 ± 0.23 mmol/L vs 0.65 ± 0.20 mmol/L (P = 0.00). However,there was no statistical signif icance between the two groups. The hepatic sinus and cellular structure of hepatic cells in treatmentgroup were abnormal. Apoptosis of hepatic cells was confi rmed by TUNEL assay. CONCLUSION: High dose selenium compounds can cause the rat liver lesion and induce cell apoptosis in vivo. High resolution 1H-MRS in vitro can detect diversified metabolism. The changing trend for different ingredient of choline compounds is not completely the same at early period of apoptosis.
基金Project supported by the National Key Technology Research and Development Program of China (Nos.40801167 and 2006BAD05B05)the Knowledge Innovation Program of the Chinese Academy of Sciences (No.KZCX3-SW-356)the Foundation of the Chinese Academy of Sciences for the Field Stations of Resources and Environment
文摘Several studies have demonstrated that soil reflectance decreases with increasing soil moisture content, or increases when the soil moisture reaches a certain content; however, there are few analyses on the quantitative relationship between soil reflectance and its moisture, especially in the case of black soils in northeast China. A new moisture adjusting method was developed to obtain soil reflectance with a smaller moisture interval to describe the quantitative relationship between soil reflectance and moisture. For the soil samples with moisture contents ranging from air-dry to saturated, the changes in soil reflectance with soil moisture can be depicted using a cubic equation. Both moisture threshold (MT) and moisture inflexion (MI) of soil reflectance can also be determined by the equation. When the moisture range was smaller than MT, soil reflectance can be simulated with a linear model. However, for samples with different soil organic matter (OM), the parameters of the linear model varied regularly with the OM content. Based on their relationship, the soil moisture can be estimated from soil reflectance in the black soil region.
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Projects(51678071,51278071)supported by the National Natural Science Foundation of ChinaProjects(14KC06,CX2015BS02)supported by Changsha University of Science&Technology,China
文摘Due to the disturbances arising from the coherence of reflected waves and from echo noise,problems such as limitations,instability and poor accuracy exist with the current quantitative analysis methods.According to the intrinsic features of GPR signals and wavelet time–frequency analysis,an optimal wavelet basis named GPR3.3 wavelet is constructed via an improved biorthogonal wavelet construction method to quantitatively analyse the GPR signal.A new quantitative analysis method based on the biorthogonal wavelet(the QAGBW method)is proposed and applied in the analysis of analogue and measured signals.The results show that compared with the Bayesian frequency-domain blind deconvolution and with existing wavelet bases,the QAGBW method based on optimal wavelet can limit the disturbance from factors such as the coherence of reflected waves and echo noise,improve the quantitative analytical precision of the GPR signal,and match the minimum thickness for quantitative analysis with the vertical resolution of GPR detection.
基金supported by National Key Research and Development Program of China(No.2016YFF0102502)the Key Research Program of Frontier Sciences,CAS(No.QYZDJ-SSW-JSC037)the Youth Innovation Promotion Association,CAS,Liao Ning Revitalization Talents Program(No.XLYC1807110)。
文摘In the spectral analysis of laser-induced breakdown spectroscopy,abundant characteristic spectral lines and severe interference information exist simultaneously in the original spectral data.Here,a feature selection method called recursive feature elimination based on ridge regression(Ridge-RFE)for the original spectral data is recommended to make full use of the valid information of spectra.In the Ridge-RFE method,the absolute value of the ridge regression coefficient was used as a criterion to screen spectral characteristic,the feature with the absolute value of minimum weight in the input subset features was removed by recursive feature elimination(RFE),and the selected features were used as inputs of the partial least squares regression(PLS)model.The Ridge-RFE method based PLS model was used to measure the Fe,Si,Mg,Cu,Zn and Mn for 51 aluminum alloy samples,and the results showed that the root mean square error of prediction decreased greatly compared to the PLS model with full spectrum as input.The overall results demonstrate that the Ridge-RFE method is more efficient to extract the redundant features,make PLS model for better quantitative analysis results and improve model generalization ability.
基金CAS Strategic Priority Research Program,No.XDA19030204CAS Western Light Program,No.2015-XBQN-B-17
文摘Quantitative analysis of the impact factors in energy-related CO2 emissions serves as an important guide for reducing carbon emissions and building an environmentally-friendly society. This paper aims to use LMDI method and a modified STIRPAT model to research the conventional energy-related CO_2 emissions in Kazakhstan after the collapse of the Soviet Union. The results show that the trajectory of CO2 emissions displayed U-shaped curve from 1992 to 2013. Based on the extended Kaya identity and additive LMDI method, we decomposed total CO2 emissions into four influencing factors. Of those, the economic active effect is the most influential factor driving CO2 emissions, which produced 110.86 Mt CO2 emissions, with a contribution rate of 43.92%. The second driving factor is the population effect, which led to 11.87 Mt CO2 emissions with a contribution rate of 4.7%. On the contrary, the energy intensity effect is the most inhibiting factor, which caused –110.90 Mt CO2 emissions with a contribution rate of –43.94%, followed by the energy carbon structure effect resulting in –18.76 Mt CO2 emissions with a contribution rate of –7.43%. In order to provide an in-depth examination of the change response between energy-related CO2 emissions and each impact factor, we construct a modified STIRPAT model based on ridge regression estimation. The results indicate that for every 1% increase in population size, economic activity, energy intensity and energy carbon structure, there is a subsequent increase in CO_2 emissions of 3.13%, 0.41%, 0.30% and 0.63%, respectively.
基金Item Sponsored by National Key Technology Research and Development Programin 11th Five-Year Plan of China(2006BAE03A00,2008BAE67B01)
文摘The granulation of blast furnace slag （BFS） with water quenching treatment has some disadvantages, such as high water consumption and difficulty for recovery heat. So developing a new dry granulation technique to treat BFS is very important. The applicability of BFS directly depends on the content of non-crystalline solids in the slag after treatment. So it is of theoretical and practical significance to analyze the content of non-crystalline solids in the slag quantitatively and simply. Metallographical test is mainly adopted to quantify the non-crystalline in BFS so far with the shortages such as complex sample, difficult determination, ect. The diffraction intensity of non-crystalline is proportionate to the content of non-crystalline in BFS, ~ray diffraction method was adopted to quantify the noncrystalline and the crystalline solids in BFS. The quantitative coefficient between the crystalline and the non-crystalline solids of BFS is 0.70 of BFS whose main composition （mass percent, %） is： CaO 38.2, SiO2 35.7, Al2Oa 16.3, and MgO 8.3. The relative error of X-ray diffractometer for quantitatively analyzing non-crystalline content of BFS is less than 1%.
基金National Natural Science Foundation of China, No.40371003 Ministry of Education of China, No.01158 Master Research Project of Shaanxi Normal University
文摘Using the theory and method of the ecological footprint, and combining the changes of regional land use, resource environment, population, society and economy, this paper calculated the ecological footprint, ecological carrying capacity and ecological surplus/loss in 1986-2002 on the Loess Plateau in northern Shaanxi Province. What is more, this paper has put forward the concept of ecological pressure index, set up ecological pressure index models, and ecological security grading systems, and the prediction models of different ecological footprints, ecological carrying capacity, ecological surplus and ecological safety change, and also has assessed the ecological footprint demands of 10,000 yuan GDE The results of this study are as follows： （1） the ecological carrying capacity in northern Shaanxi shows a decreasing trend, the difference of reducing range is the fastest; （2） the ecological footprint appears an increasing trend; （3） ecological pressure index rose to 0.91 from 0.44 during 1986-2002 on the Loess Plateau of northern Shaanxi with an increase of 47%; and （4） the ecological security in the study area is in a critical state, and the ecological oressure index has been increasing rapidlv.
基金Under the auspices of the Major State Basic Research Development Program of China (973 Program) (No 2005CB724201)
文摘Ecological footprint （EF） has attracted much attention internationally as a potential indicator for sustainable development. In China, EF has also gained recognition in related fields and disciplines. Moreover, some scholars in these fields have proposed alternative methods to calculate EF and have made some progress. This paper, therefore, begins with the introduction and development of EF in China. However, the established methods of EF calculation hold some limitations, such as indicator variance and result abnormality. In order to resolve those problems, the authors make a further modification considering the demand of EF as a comprehensive indicator： 1） More accurate analysis has been done to divide EF into several parts： imported EF, exported EF, and producible EF, which is the solution to the problem of abnormality in original EF results and can explain abnormal phenomena reasonably. 2） Considering the actual situa- tion of Shanghai, emended equivalence factor is brought forward and a matrix is formed with equivalence factors. The measure can reduce the deviation between the fact and the results. 3） The calculation compares local yield with global average yield to analyze the effects of yields. And based on local yields in different years, the results are more accurate. Finally, the calculation method is applied to calculating EF of Shanghai from 1980 to 2003, and the subsequent detailed analysis is presented. Available data and results suggest a statistically significant correlation coefficient between EF and GDP, population density and urbaniTation level. Through analyzing the process of calculating EF and its results, it can be seen that EF, as a macro-indicator, can not exactly indicate whether development within a region can meet the re- quests of sustainable development, which can be explained by the fact that the result of EF is impacted greatly by sub- jective factors including national policy,available technology, population, etc. Nevertheless, EF can demonstrate, at least to some degree, the regional status in terms of resources and energy consumption, as well as developmental potential. The calculation of EF, therefore, deserves further research to achieve more far-reaching significance in application.
文摘In this paper, a double artificial neural network （DANN） algorithm was used to parse near infrared （NIR） reflectance spectrum of Cofrel medicines. The contents of benproperine phosphate, which is the effective ingredient in Cofrel medicines, were accurately nondestructive quantitatively predicted. Compared the results with those of HPLC, the relative errors （RE %） were less than 0.18%. The analytical results could be applied to qualitative control of Cofrel medicines.
基金supported by the National Key R&D Program of China(Nos.2017YFE0301506 and 2017YFE0301306)。
文摘Tokamak exhaust is an important part of the deuterium-tritium fuel cycle system in fusion reactions.In this work,we present a laser-induced breakdown spectroscopy(LIBS)-based method to monitor the gas compositions from the exhaust system in the tokamak device.Helium(He),a main impurity in the exhaust gas,was mixed with hydrogen(H_(2))in different ratios through a self-designed gas distribution system,and sealed into a measurement chamber as a standard specimen.A 532 nm wavelength laser pulse with an output power of 100 mJ was used for plasma excitation.The time-resolved LIBS is used to study the time evolution characteristics of the signal strength,signal-to-background ratio(SBR),signal-to-noise ratio(SNR)and relative standard deviation(RSD)of the helium and hydrogen characteristic lines.The Boltzmann twoline method was employed to estimate the plasma temperature of laser-induced plasma(LIP).The Stark-broadened profile of He I 587.56 nm was exploited to measure the electron density.From these studies,an appropriate time was determined in which the low RSD%was consistent with the high signal-to-noise ratio.The He I 587.56 nm and Hαemission lines with good signalto-noise ratio were extracted from the spectrum and used in the external standard method and internal standard method for quantitative analysis.The test results for mixed gas showed that the average relative error of prediction was less than 11.15%,demonstrating the great potential of LIBS in detecting impurities in plasma exhaust gas.
文摘Mercury ions are highly toxic and can accumulate along food chains in water,soil,crops and animals.Effective detection of mercury ions in various media is of great significance for maintaining the ecological environment and protecting people's health.In this work,a mercury ions specific fluorescent probe was developed by a simple one-step reaction of commercial substrates of 4-chloro-7-nitro-2,1,3-benzoxadiazole and 1-(2-aminoethyl)-4-methylpiperazine.Investigation on sensing behavior showed that this probe had high sensitivity and selectivity towards mercury ions.Furthermore,this probe could be used as a tool to track the level of mercury ions in living system.In living cells,the probe with green emission emitted a bright red fluorescence when it was bound to mercury ions.In Arabidopsis thaliana,similar red emission could be detected from the root tip and stalk when A.thaliana was grown in culture medium containing mercury ions.The imaging in zebrafish showed that mercury ions were mainly concentrated in the stomach and head of zebrafish.Especially,this probe could be applied in quantitative analysis of mercury ions in tap water,green tea,sea shrimp and soil.This work provided a practical tool for the detection of mercury ions in living systems and quantitative analysis in real samples.
基金supported by the Natural Science Foundation of China(NSFC,Nos.21471103,51631001,11574173 and 21603014)the Scientific Research Base Development Program and the science and technology innovation service ability construction project of the Beijing Municipal Commission of Education。
文摘Surface-enhanced Raman scattering(SERS)is a powerful spectroscopic tool in quantitative analysis of molecules,where the substrate plays a critical role in determining the detection performance.Herein,a silver nanocubes/polyelectrolyte/gold film sandwich structure was prepared as a reproducible,highperformance SERS substrate by the wate r/oil inte rfacial assembly method.In addition to the hot spots on the nanocubes surface,the edge-to-edge interspace of the Ag nanocubes led to marked enhancement of the SERS intensity,with a limit of detection of 10~(11)mol/L and limit of quantitation of 10~(10)mol/L for crystal violet.When rhodamine 6 G and crystal violet were co-adsorbed on the Ag nanocube surfaces,the characteristic SERS peaks of the two molecules remained well resolved and separated,and the peak intensities varied with the respective concentration,which could be exploited for concurrent detection of dual molecules.Results from this work indicate that organized ensembles of Ag nanocubes can serve as effective SERS substrate can for sensitive analysis for complex molecular systems.
