Quantitative analysis and time-resolved characterization of simulated tokamak exhaust gas by laser-induced breakdown spectroscopy

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.

Quantitative evaluation of geological fluid evolution and accumulated mechanism:in case of tight sandstone gas field in central Sichuan Basin

Tight gas exploration plays an important part in China’s unconventional energy strategy.The tight gas reservoirs in the Jurassic Shaximiao Formation in the Qiulin and Jinhua Gas Fields of central Sichuan Basin are characterized by shallow burial depths and large reserves.The evolution of the fluid phases is a key element in understanding the accumulation of hydrocarbons in tight gas reservoirs.This study investigates the fluid accumulation mechanisms and the indicators of reservoir properties preservation and degradation in a tight gas reservoir.Based on petrographic observations and micro-Raman spectroscopy,pure CH4 inclusions,pure CO2 inclusions,hybrid CH4–CO2 gas inclusions,and N2-rich gas inclusions were studied in quartz grains.The pressure–volume–temperature–composition properties(PVT-x)of the CH4 and CO2 bearing inclusions were determined using quantitative Raman analysis and thermodynamic models,while the density of pure CO2 inclusions was calculated based on the separation of Fermi diad.Two stages of CO2 fluid accumulation were observed:primary CO2 inclusions,characterized by higher densities(0.874–1.020 g/cm3)and higher homogenization temperatures(>210°C)and secondary CO2 inclusions,characterized by lower densities(0.514–0.715 g/cm3)and lower homogenization temperatures:~180–200°C).CO2 inclusions with abnormally high homogenization temperatures are thought to be the result of deep hydrothermal fluid activity.The pore fluid pressure(44.0–58.5 MPa)calculated from the Raman shift of C–H symmetric stretching(v1)band of methane inclusions is key to understanding the development of overpressure.PT entrapment conditions and simulation of burial history can be used to constrain the timing of paleo-fluid emplacement.Methane accumulated in the late Cretaceous(~75–65 Ma),close to the maximum burial depth during the early stages of the Himalayan tectonic event while maximum overpressure occurred at~70 Ma,just before uplift.Later,hydrocarbon gas migrated through the faults and gradually displaced the early emplaced CO2 in the reservoirs accompanied by a continuous decrease in overpressure during and after the Himalayan event,which has led to a decrease in the reservoir sealing capabilities.The continuous release of overpressure to present-day conditions indicates that the tectonic movement after the Himalayan period has led to a decline in reservoir conditions and sealing properties.

Quantitative Method of the Structural Damage Identification of Gas Explosion Based on Case Study:The Shanxi “11. 23” Explosion Investigation

In order to present a retrospective analysis of exposition accidents using input data from investigation processes,data from a specific accident was examined,in which we analyzed possible involved gas species（ liquefied petroleum gas; nature gas） and computed their concentrations and distributions based on the interactions between the structures and the effects of the explosion. In this study,5 scenarios were created to analyze the impact effect. Moreover,a coupling algorithm was put into practice,with a practical outflow boundary and joint strength are applied. Finally,the damage effects of each scenario were simulated. Our experimental results showed significant differences in the 5 scenarios concerning the damage effects on the building structures. The results from scenario 3 agree with the accident characteristics,demonstrating the effectiveness of our proposed modeling method. Our proposed method reflects gas properties,species and the concentration and distribution,and the simulated results validates the root cause,process,and consequences of accidental explosions. Furthermore,this method describes the evolution process of explosions in different building structures. Significantly,our model demonstrates the quantatative explosion effect of factors like gas species,gas volumes,and distributions of gases on explosion results. In this study,a feasible,effective,and quantitative method for structure safety is defined,which is helpful to accelerate the development of safer site regulations.

Explosion Hazard Analysis of Liquefied Petroleum Gas Transportation

This paper presents a quantitative risk analysis of liquefied petroleum gas(LPG)transportation.An accident that happened on June 13,2020,on the highway near Wenling,China is studied as a case.In this accident,LPG carried by a tank truck on the highway leaked and caused a large explosion,which led to 20 deaths.Different methods are combined to calculate the consequence of the accident.Multi-energy model and rupture of vessel model are employed to calculate the overpressure;the simulation result of the multi-energy model is closer to the damage caused by the accident.The safety distances in accidents of LPG transport storage tanks of different capacities are calculated in this study;the results show that the damage of explosion will increase with the filling degree of the tank.Even though the filling degree is 90%(value required by law),the 99%fatality rate range will reach 42 m,which is higher than regulated distance between road and building.The social risk of the tank truck has also been calculated and the results show that the risk is not acceptable.The calculating method used in this study could evaluate the risk of LPG tanker more accurately,which may contribute to the establishment of transportation regulation so that losses from similar accidents in the future could be reduced.

Simultaneous determination of five phenylethanoid glycosides in Cistanches Herba using quantitative analysis of multi-components by single marker

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.

Gas Chromatography–Mass Spectrometry for Quantitative and Qualitative Analysis of Essential Oil from Curcuma wenyujin Rhizomes

Objectives:A rapid and sensitive gas chromatography–mass spectrometry(GC–MS)method for quantitative and qualitative analysis of essential oil from Curcuma wenyujin rhizomes was established.Methods:The essential oil of C.wenyujin rhizomes was extracted by supercritical CO2 extraction(SFE).Six main bioactive compounds(eucalyptol,β-elemene,curzerene,germacrone,curdione,and curcumol)were analyzed in selected ion monitoring mode(SIM).Results:Curzerene is not originally present in C.wenyujin rhizomes,but is a product of the transformation of furanodiene at high temperature.The six target components demonstrated good linearity(R2>0.9979)over a relatively wide concentration range.The interday and intraday variations had relative standard deviation values less than 5%and the average recovery ranged from 96.95%to 100.04%.The limit of quantitation ranged from 0.032 to 0.235μg/mL.The developed method was successfully used to analyze the six compounds in 17 samples collected from different origins.Significant variation was observed for the concentrations of the six compounds.In addition,51 constituents were identified in C.wenyujin rhizome essential oil,consisting of 87.66%of the total essential oil,including curdione,curzerene,dehydrocurdione,germacrone,1,4-bis(2-benzimidazoyl)benzene,neocurdione,curcumenone,andβ-elemene.Conclusions:The proposed method will be useful in the quality control of C.wenyujin rhizome essential oil production.

Numerical simulation to determine the gas explosion risk in longwall goaf areas:A case study of Xutuan Colliery

Underground gassy longwall mining goafs may suffer potential gas explosions during the mining process because of the irregularity of gas emissions in the goaf and poor ventilation of the working face,which are risks difficult to control.In this work,the 3235 working face of the Xutuan Colliery in Suzhou City,China,was researched as a case study.The effects of air quantity and gas emission on the three-dimensional distribution of oxygen and methane concentration in the longwall goaf were studied.Based on the revised Coward’s triangle and linear coupling region formula,the coupled methane-oxygen explosive hazard zones(CEHZs)were drawn.Furthermore,a simple practical index was proposed to quantitatively determine the gas explosion risk in the longwall goaf.The results showed that the CEHZs mainly focus on the intake side where the risk of gas explosion is greatest.The CEHZ is reduced with increasing air quantity.Moreover,the higher the gas emission,the larger the CEHZ,which moves towards the intake side at low goaf heights and shifts to the deeper parts of the goaf at high heights.In addition,the risk of gas explosion is reduced as air quantities increase,but when gas emissions increase to a higher level(greater than 50 m3/min),the volume of the CEHZ does not decrease with the increase of air quantity,and the risk of gas explosion no longer shows a linear downward trend.This study is of significance as it seeks to reduce gas explosion accidents and improve mine production safety.

Experimental study on mercury content in flue gas of coal-fired units based on laser-induced breakdown spectroscopy

Accurate measurement of trace heavy metal mercury(Hg) in flue gas of coal-fired units is great significance for ecological and environmental protection.Mixed gas was used to simulate the actual flue gas of a power plant in this study.A laser-induced breakdown spectroscopy(LIBS)system for Hg measurement in mixed gas was built to study the effect of mixed gas pressure,Hg concentration in mixed gas and delay time on Hg measurement.The experimental results show that the appropriate low mixed gas pressure can obtain high Hg signal intensity and signal to noise ratio.The Hg signal intensity and signal to noise ratio increased with the increase of Hg concentration in mixed gas.The Hg signal intensity and signal to noise ratio decreased with the increase in delay time.According to the above results,the optimized measurement conditions can be determined.Different Hg concentrations in mixed gas were quantitatively analyzed by the internal standard method and traditional calibration method respectively.The relative error of prediction of the test sample obtained by the internal standard method was within 11.11%.The relative error of prediction of the traditional calibration method was less than 14.54%.This proved that the internal standard method can improve the accuracy of quantitative analysis of Hg concentration in flue gas using LIBS.

Flue Gas Monitoring System With Empirically-Trained Dictionary

The monitoring of flue gas of the thermal power plants is of great significance in energy conservation and environmental protection.Spectral technique has been widely used in the gas monitoring system for predicting the concentrations of specific gas components.This paper proposes flue gas monitoring system with empirically-trained dictionary(ETD)to deal with the complexity and biases brought by the uninformative spectral data.Firstly,ETD is extracted from the raw spectral data by an alternative optimization between the sparse coding stage and the dictionary update stage to minimize the error of sparse representation.D1,D2 and D3 are three types of ETD obtained by different methods.Then,the predictive model of component concentration is constructed on the ETD.In the experiments,two real flue gas spectral datasets are collected and the proposed method combined with the partial least squares,the background propagation neural network and the support vector machines are performed.Moreover,the optimal parameters are chosen according to the 10-fold root-mean-square error of cross validation.The experimental results demonstrate that the proposed method can be used for quantitative analysis effectively and ETD can be applied to the gas monitoring systems.

Simultaneous Determination of Five Components in Operculina turpethum

[Objectives]This study was conducted to establish a method for the simultaneous determination of caffeic acid, rutin, ononin, luteolin, and apigenin in Operculina turpethum(L.) S. Manso. [Methods]With ononin from O. turpethum as the internal reference, the five components were separated by HPLC, and the contents of various components were calculated according to the relative correction factors of ononin with caffeic acid, rutin, luteolin, and apigenin. Meanwhile, the calculated results of quantitative analysis of multi-components by single marker(QAMS) were compared with the determined values of the external standard method. [Results] The linear relationship of the five components in their respective ranges was good(r=0.999 9). The average recovery was in the range of 97.48%-101.05%, and the RSD values were in the range of 1.04%-2.71%. The results obtained by QAMS were close to those obtained by the external standard method. [Conclusions] The method is accurate, stable and adaptable, and can be used for the determination of five flavonoids in O. turpethum.

一测多评技术在鼻咽解毒胶囊质量评价中的应用

目的建立鼻咽解毒胶囊一测多评的含量测定方法 ,验证该方法在鼻咽解毒胶囊质量控制中应用的可行性和准确性。方法以盐酸小檗碱为内参物,建立盐酸小檗碱与黄芩苷的相对校正因子,同时根据盐酸小檗碱与巴马汀、黄连碱、表小檗碱的内在函数关系,应用于含量测定,建立其一测多评法的多指标质量控制方法。结果建立了鼻咽解毒胶囊中多种成分一测多评法方法学的考察模式。结论以盐酸小檗碱、巴马汀、黄连碱、表小檗碱和黄芩苷为指标,采用一测多评法控制鼻咽解毒胶囊质量可行。

高纯氮载气中Kr的简便PVT定量方法

A simple PVT quantitative method of Kr in the high pure N2 was studied. Pressure, volume and temperature of the sample gas were measured by three individual methods to obtain the sum sample with food uncertainty. The ratio of Kr/N2 could be measured by GAM400 quadrupole mass spectrometer. So the quantity of Kr could be calculated with the two measured data above. This method can be suited for quantitative analysis of other simple composed noble gas sample with high pure carrying gas.

A Quantitative Method for Simultaneous Determination of Four Anthraquinones with One Marker in Rhei Radix et Rhizoma

Objective To develop a quantitative method for simultaneously determining multi-components in Rhei Radix et Rhizoma using one chemical reference substance.Methods The contents of multi-components were calculated by the UV relative correction factors(RCFs)of chrysophanol,physcion,and rhein to emodin.Results The values of RCFs at 274 nm for rhein,chrysophanol,and physcion to emodin were 0.712,0.674,and 1.051.The calibration curves were linear over the ranges of 0.02-4.08,0.02-4.12,0.07-12.92,and 0.02-3.68μg/mL for rhein,emodin, chrysophanol,and physcion,respectively.The contents of emodin in 18 samples were determined by the external standard method,and the contents of the other three anthraquinone aglycones were calculated according to their RCFs. Conclusion No significant difference is found in comparison with the classical method,indicating that the RCFs have high reliability within their linear ranges and could be used in quality control of Rhei Radix et Rhizoma.The quantitative analysis of multi-component with a single marker is especially suitable for herbal medicines containing unstable or hard to be purified components as quality control markers.

A double integral method for quantitative evaluation of influence on thin-walled casing response caused by bearing uncertainties

Bearings in a gas turbine engine are the key connecting components transmitting force and motion between rotors and thin-walled flexible casing.The bearing stiffness and damping of squeeze film damper(SFD)nearby bearings are easily affected by many factors,such as assembly process,load condition and temperature variation,resulting in uncertainties.The uncertainties may influence the response of the measuring point on the casing.Hence,it is difficult to carry out the fault diagnosis,whole machine balancing and other related works.In this paper,a double integral quantitative evaluation method is proposed to simultaneously analyze the influence of two uncertain dynamic coefficients on the response amplitude and phase of casing measuring points.Meanwhile,the coupling influence of stiffness and damping accompanied by dramatic changes with rotational speeds are essentially discussed.As an example,a typical engine bearing-casing system with complex dynamic characteristics is analyzed.The impact of uncertain dynamic coefficients on the unbalance response is quantitatively evaluated.

Fast Quantification of the Mixture of Polycyclic Aromatic Hydrocarbons Using Surface-Enhanced Raman Spectroscopy Combined with PLS-GA-BP Network

To realize the fast and accurate quantitative analysis of the mixture of polycyclic aromatic hydrocarbons(PAHs),surface-enhanced Raman spectroscopy(SERS)coupled with multivariate calibrations were employed.In this study,three kinds of calibration algorithms were used to quantitative analysis of the mixture of naphthalene(Nap),phenanthrene(Phe),and pyrene(Pyr).Firstly,partial least squares(PLS)algorithm was used to select characteristic variables,then the global search capability of genetic algorithm(GA)was used for the determining of the initial weights and thresholds of back propagation(BP)neural network so that local minima was avoided.The PLS-GA-BP model exhibited superiority to quantify PAHs mixture,which achieved R2=0.9975,0.9710,0.9643,ARE=10.07%,19.28%,16.72%and RMSE=13.10,5.40,5.10 nmol L−1 for Nap,Phe,Pyr(in the PAHs mixture)concentration prediction respectively.The forecast error,ARE and RMSE have been reduced more than 50%and 60%respectively compared with the whole spectral BP model.The study indicates that accurate quantitative spectroscopic analysis of the mixture of PAHs samples can be achieved through the combination of SERS technique and PLS-GA-BP algorithm.

Application of Fingerprint Combined with QAMS in Quality Evaluation of Zhenrongdan Mixture

[Objectives] The research aimed to evaluate the quality of Zhenrongdan mixture by fingerprint combining QAMS. [Methods] The quality evaluation method was established and validated with echinacoside as internal reference to determine the contents of other components(ferulic acid, salvianolic acid B, and icariin) according to the relative correction factor. The accuracy and feasibility of QAMS were evaluated by comparison on the results between the measured value and calculation value by external standard method and QAMS. [Results] A common pattern of characteristic fingerprint of Zhenrongdan mixture by HPLC was established. Thirteen common peaks were identified, and they account for 91% of the total peak area, and four components were verified in five batches of Zhenrongdan mixture. Good similarities with correlation coefficients higher than 0.99 were found in the fingerprints. There was no significant difference between the quantitative results of the four ingredients in the five batches by external standard method and QAMS. [Conclusions] The method of fingerprint combined with QAMS could be used for the quality control of multiple components determination and fingerprint chromatography for Zhenrongdan mixture.

Overview of the quality standard research of traditional Chinese medicine

Traditional Chinese medicine(TCM)has been widely used for the prevention and treatment of various diseases for a long time in China.Due to its proven efficacy,wide applications,and low side effect,TCM has increasingly attracted worldwide attention.However,one of the biggest challenges facing the clinical practice of TCM is the uncontrollable quality.In this review,the progress of the development and the current status of quality standard as well as new quality control techniques introduced in Chinese Pharmacopoeia(2010 edition),such as liquid chromatography hyphenated mass spectrometry(LC-MS),fingerprint,quantitative analysis of multi-components by single-marker(QAMS),thin layer chromatography bio-autographic assay(TLC-BAA),and DNA molecular marker technique,are briefly overviewed.