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AN INCREMENTAL METHOD OF X-RAY DIFFRACTION QUANTITATIVE PHASE ANALYSIS OF SAMPLESCONTAINING AMORPHOUS MATERIAL
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作者 G. Chu(Department of Applied Chemistry Fushun Petroleum Institute, Fushun 113001, China) 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1997年第1期35-38,共4页
A new method for quantitative X-ray diffraction phase analysis of a powder misture has been developed according to Popovic's doping method. The weight fraction of amorphous material in the analysed sample is obtai... A new method for quantitative X-ray diffraction phase analysis of a powder misture has been developed according to Popovic's doping method. The weight fraction of amorphous material in the analysed sample is obtained. For a multicomponent system in which (n-2) pure phases are added into an n-phase compnent sample and theweight fractions of all n phases can be determined by the method. The test results of confirmation agree well with the theory. 展开更多
关键词 x-ray diffraction quantitative phase analysis amorphous material mass absorption coefficient
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A SOLUTION OF MINIMUM NORM FOR QUANTITATIVE PHASE ANALYSIS BY STANDARDLESS X-RAY DIFFRACTION
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作者 ZHAO Han GONG Yansheng SHEN Jingyuan RUAN Qikuan JIN Jialing ZHU Hanyu Research Institute of Qiqihar Steel Works,Fulaerji,China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1991年第9期225-229,共5页
A new expression of quantitative phase analysis by standardless X-ray diffraction has been derived using intensity matrix of vector modulus.The criterion of standardless X-ray diffraction analysis was suggested,so as ... A new expression of quantitative phase analysis by standardless X-ray diffraction has been derived using intensity matrix of vector modulus.The criterion of standardless X-ray diffraction analysis was suggested,so as to separate the diffraction pattern of every phase from that of sample.The optimal solution could be obtained by the least squares regression. 展开更多
关键词 x-ray diffraction standardless phase analysis least square regression
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A SOLUTION OF MINIMUM NORM FOR QUANTITATIVE PHASE ANALYSIS BY STANDARDLESS X-RAY DIFFRACTION
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作者 ZHAO Han GONG Yansheng SHEN Jingyuan RUAN Qikuan JIN Jialing ZHU Hanyu Research Institute of Qiqihar Steel Works,Fulaerji,China GONG Yansheng Senior Engineer,Research Institute of Qiqihar Steel Works,Filaerji 161041,China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1990年第9期225-229,共5页
A new expression of quantitative phase analysis by standardless X-ray diffraction has been derived using intensity matrix of vector modulus,The criterion of standardless X-ray diffraction analysis was suggested,so as ... A new expression of quantitative phase analysis by standardless X-ray diffraction has been derived using intensity matrix of vector modulus,The criterion of standardless X-ray diffraction analysis was suggested,so as to separate the diffraction pattern of every phase from that of sample.The optimal solution could be obtained by the least squares regression. 展开更多
关键词 x-ray diffraction standardless phase analysis least square regression
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AN EXTERNAL STANDARD METHOD OF QUANTITATIVE PHASE ANALYSIS OF THE SAMPLE CONTAINING AN AMORPHOUS PHASE BY X—RAY DIFFRACTION 被引量:5
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作者 CHU Gang, SUI QinFushun Petroleum Institute. Fushun. China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1994年第3期179-182,共4页
A new method of the quantitative phase analysis of the sample containing an amorphous phase or a standardless phase by X-ray diffraction is proposed in the paper. The addtion of a reference phase or some analytical ph... A new method of the quantitative phase analysis of the sample containing an amorphous phase or a standardless phase by X-ray diffraction is proposed in the paper. The addtion of a reference phase or some analytical phase to the analyzed sample is not required in this method and the experimental results are satisfactory. 展开更多
关键词 quantitative phase analysis x-ray diffraction
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Quantitative Phase Analysis Based on Rietveld Structure Refinement for Carbonate Rocks 被引量:1
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作者 Mehmet Tamer 《Journal of Modern Physics》 2013年第8期1149-1157,共9页
QPA (Quantitative Phase Analysis) of carbonate rocks bearing calcite and dolomite using X-ray diffractometry (XRD) can be performed using the combined Rietveld Structure Refinement (RSR) and semiquantitative Reference... QPA (Quantitative Phase Analysis) of carbonate rocks bearing calcite and dolomite using X-ray diffractometry (XRD) can be performed using the combined Rietveld Structure Refinement (RSR) and semiquantitative Reference Intensity Ratio (RIR) methods, providing an estimation of crystalline phase in a mixture. Different ratios of five samples were prepared by mixing these crystal minerals with high sensitively. The scan speeds, adequate to determine mineral phases in rock samples, were used as 6 degrees per minute with 0.08 steps. The XRD analysis with commercial TOPAS 3.0 program, defined by a new generation of profile and structure analysis software, based on RSR provides Bragg reflection profiles and the dimension of the unit cell of a phase. The weight fractions of each phase were found by Le Bail and Pawley methods in RSR using a pseudo-Voigt peak shape model. The samples were also characterized by using X-ray fluorescence (XRF) and atomic absorption spectrometer (AAS). These analyses were conducted to compare these results with those obtained from the RSR. In addition to these, RSR of phases is very important to improve the goodness of fit (GOF). Therefore, the discussions of refinement of the carbonate mixing were made and a refinement procedure was given for these mixing in detail. Taking advantage of the RSR with the addition of an internal standard, the phase fraction of all the crystalline phases as well as the amorphous component, has been accurately determined. RSR technique offers a valid support for the characterization of marble in the light of industrial products. 展开更多
关键词 quantitative phase analysis RIETVELD Structure REFINEMENT Reference INTENSITY Ratio CALCITE DOLOMITE TOPAS
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Quantitative Phase Analysis of the Calcium Silicate Slag as the Residue of Extracting Alumina from High-Alumina Fly Ash
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作者 黄冬波 宗燕兵 +2 位作者 刘晓明 彭丹丹 杨志杰 《Journal of Shanghai Jiaotong university(Science)》 EI 2016年第6期729-736,共8页
Calcium silicate slag is the residue of process of pre-desilication alkali lime sintering applied in the high-alumina fly ash to extract the alumina.The quantitative phase analysis(QPA) of the calcium silicate slag ha... Calcium silicate slag is the residue of process of pre-desilication alkali lime sintering applied in the high-alumina fly ash to extract the alumina.The quantitative phase analysis(QPA) of the calcium silicate slag has been performed by the Rietveld method based on the powder X-ray diffraction(XRD) with the aid of noncommercial software GSAS-EXPGUI.A known weight of crystalline internal standard(10% CaF_2) was added to the calcium silicate slag to calculate the fraction of amorphous phase and other crystalline phases on an absolute basis.Besides,the calcium silicate slag was characterized by X-ray fluorescence(XRF) and thermo gravimetric(TG) differential scanning calorimetry(DSC) to test the QPA results and investigate its other characters.Finally,the results show that the amorphous fraction is 17.5%(hereinafter,the percentages refer to the mass fraction),and the major crystalline phases detected in the calcium silicate slag consist of 23.5% Beta-Ca_2 SiO_4,10.0% bredigite,10.3% Ca_3Al_2O_6(C_3A) and 21.6% CaCO_3. 展开更多
关键词 calcium silicate slag x-ray diffraction(XRD) quantitative phase analysis(QPA) Rietveld method
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Energy-dispersive X-ray Spectroscopy for the Quantitative Analysis of Pyrite Thin Specimens
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作者 LUO Tingting GUO Yi +4 位作者 DENG Zhao LIU Xiaoqing SUN Zhenya QI Yanyuan YANG Meijun 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2023年第6期1304-1310,共7页
To explore ways to improve the accuracy of quantitative analysis of samples in the micrometer to nanometer range of magnitudes,we adopted analytical transmission electron microscopy(AEM/EDS)for qualitative and quantit... To explore ways to improve the accuracy of quantitative analysis of samples in the micrometer to nanometer range of magnitudes,we adopted analytical transmission electron microscopy(AEM/EDS)for qualitative and quantitative analysis of pyrite materials.Additionally,the k factor of pyrite is calculated experimentally.To develop an appropriate non-standard quantitative analysis model for pyrite materials,the experimentally calculated k factor is compared with that estimated from the non-standard quantitative analytical model of the instrument software.The experimental findings demonstrate that the EDS attached to a TEM can be employed for precise quantitative analysis of micro-and nanoscale regions of pyrite materials.Furthermore,it serves as a reference for improving the results of the EDS quantitative analysis of other sulfides. 展开更多
关键词 analytical transmission electron microscopy(AEM) energy dispersive x-ray spectroscopy(EDS) PYRITE thin specimen quantitative analysis
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Automatic recognition and quantitative analysis of Ω phases in Al-Cu-Mg-Ag alloy
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作者 刘冰滨 谷艳霞 +1 位作者 刘志义 田小林 《Journal of Central South University》 SCIE EI CAS 2014年第5期1696-1704,共9页
The main methods of the second phase quantitative analysis in current material science researches are manual recognition and extracting by using software such as Image Tool and Nano Measurer. The weaknesses such as hi... The main methods of the second phase quantitative analysis in current material science researches are manual recognition and extracting by using software such as Image Tool and Nano Measurer. The weaknesses such as high labor intensity and low accuracy statistic results exist in these methods. In order to overcome the shortcomings of the current methods, the Ω phase in A1-Cu-Mg-Ag alloy is taken as the research object and an algorithm based on the digital image processing and pattern recognition is proposed and implemented to do the A1 alloy TEM (transmission electron microscope) digital images process and recognize and extract the information of the second phase in the result image automatically. The top-hat transformation of the mathematical morphology, as well as several imaging processing technologies has been used in the proposed algorithm. Thereinto, top-hat transformation is used for elimination of asymmetric illumination and doing Multi-layer filtering to segment Ω phase in the TEM image. The testing results are satisfied, which indicate that the Ω phase with unclear boundary or small size can be recognized by using this method. The omission of these two kinds of Ω phase can be avoided or significantly reduced. More Ω phases would be recognized (growing rate minimum to 2% and maximum to 400% in samples), accuracy of recognition and statistics results would be greatly improved by using this method. And the manual error can be eliminated. The procedure recognizing and making quantitative analysis of information in this method is automatically completed by the software. It can process one image, including recognition and quantitative analysis in 30 min, but the manual method such as using Image Tool or Nano Measurer need 2 h or more. The labor intensity is effectively reduced and the working efficiency is greatly improved. 展开更多
关键词 auto pattern recognition top-hat transformation second phases in A1 alloy quantitative analysis
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MULTI-PEAK MATCH INTENSITY RATIO METHOD OF QUANTI-TATIVE X-RAY DIFFRACTION PHASE ANALYSIS 被引量:5
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作者 G. Chu, Y.F. Cong and H.J. YouResearch Center of Analysis and Test, Liaoning University of Petroleum & Chemical Technology, Fushun 113001, China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2003年第6期489-494,共6页
A new method for quantitative phase analysis is proposed by using X-ray diffraction multi-peak match intensity ratio. This method can obtain the multi-peak match intensity ratio among each phase in the mixture sample ... A new method for quantitative phase analysis is proposed by using X-ray diffraction multi-peak match intensity ratio. This method can obtain the multi-peak match intensity ratio among each phase in the mixture sample by using all diffraction peak data in the mixture sample X-ray diffraction spectrum and combining the relative intensity distribution data of each phase standard peak in JCPDS card to carry on the least square method regression analysis. It is benefit to improve the precision of quantitative phase analysis that the given single line ratio which is usually adopted is taken the place of the multi-peak match intensity ratio and is used in X-ray diffraction quantitative phase analysis of the mixture sample. By analyzing four-group mixture sample, adopting multi-peak match intensity ratio and X-ray diffraction quantitative phase analysis principle of combining the adiabatic and matrix flushing method, it is tested that the experimental results are identical with theory. 展开更多
关键词 x-ray diffraction multi-peak match intensity ratio quantitative phase analysis
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CORRELATION OF THE COMPONENTS OF PORTLAND CEMENT CLINKER AND SINTERING PROCESS BY MEANS OF XRD QUANTITATIVE ANALYSIS
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作者 Jiang Yonghui Chen Yuankui 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 1995年第1期10-16,共7页
In this paper,the cement clinkers from various industrial Kilns were investigated by a superposing peaks method for X-ray quantitative analysis(XRQA)of clinker minerals,the results show that the clinker mineral conten... In this paper,the cement clinkers from various industrial Kilns were investigated by a superposing peaks method for X-ray quantitative analysis(XRQA)of clinker minerals,the results show that the clinker mineral contents measured by XRQA method better accord with the reality of clinkers made in different conditions than theoretic contents calculated by Bouge formula do.The measured contents of C3S of clinkers manufactured in rotary kilns are higher than theoretically calculated values,whereas,the results of clinker man manufactured in shaft kilns are contrary to that.This is because in rotary kiln,the raw meals are fully pre-heated and have high sintering temperature,the clinkers are well solid-solutioned and rapidly cooled,on the contrary,owing to the struetural defects,it is easy to exist reducing atmosphere and lower temperature in shaft kiln,moreover the cooling rate is slower,all these can evidently Lead to worse clinker quality.Adding CaF2-Ca-SO4 complex mineralizer can remarkably modify the sintering situation in shaft kiln,especially can evidently increase C3S content and make it well crystallized,therefore,im prove the sintered quality of clinker. 展开更多
关键词 x-ray quantitative analysis CLINKER MINERAL SINTERED QUALITY
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A New Method for Clay Mineral Analysis and Its Application in Geology 被引量:3
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作者 王河锦 鲁安怀 陈涛 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2002年第4期429-436,共8页
X-ray diffraction (XRD) peaks in a low-angle diffraction section of clayminerals, especially those of authigenic origin, have broadening and tailing features in shape.Using the five basic parameters, peak position, pe... X-ray diffraction (XRD) peaks in a low-angle diffraction section of clayminerals, especially those of authigenic origin, have broadening and tailing features in shape.Using the five basic parameters, peak position, peak height, width, shape coefficient and asymmetry,to describe an XRD peak is more accurate, comprehensive and integrated than using only 3 of them,position, height and width. Following the concept of the five basic parameters of an XRD peak, theprogram Decoform proposed in this study provides more information in mineralogical analyses byfitting actual XRD profiles. In combination with the HW-IR plot, Decoform can he systematically andaccurately used in the comprehensive analyses of crystallinity, domain size, lattice strain andquantitative phase. It is also of value for the geological investigations of diagenesis,metamorphism, basin maturity, structural stress field and so on. 展开更多
关键词 clay minerals x-ray diffraction analysis XRD peak fitting CRYSTALLINITY domain size lattice strain quantitative analysis application in geology
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Performance analysis of quantitative phase retrieval method in Zernike phase contrast X-ray microscopy
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作者 陈恒 高昆 +2 位作者 王大江 宋礼 王志立 《Chinese Physics C》 SCIE CAS CSCD 2016年第2期107-112,共6页
Since the invention of Zernike phase contrast method in 1930,it has been widely used in optical microscopy and more recently in X-ray microscopy.Considering the image contrast is a mixture of absorption and phase info... Since the invention of Zernike phase contrast method in 1930,it has been widely used in optical microscopy and more recently in X-ray microscopy.Considering the image contrast is a mixture of absorption and phase information,we recently have proposed and demonstrated a method for quantitative phase retrieval in Zernike phase contrast X-ray microscopy.In this contribution,we analyze the performance of this method at different photon energies.Intensity images of PMMA samples are simulated at 2.5 keV and 6.2 keV,respectively,and phase retrieval is performed using the proposed method.The results demonstrate that the proposed phase retrieval method is applicable over a wide energy range.For weakly absorbing features,the optimal photon energy is 2.5 keV,from the point of view of image contrast and accuracy of phase retrieval.On the other hand,in the case of strong absorption objects,a higher photon energy is preferred to reduce the error of phase retrieval.These results can be used as guidelines to perform quantitative phase retrieval in Zernike phase contrast X-ray microscopy with the proposed method. 展开更多
关键词 x-ray microscopy Zernike phase contrast quantitative phase retrieval
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长期服役后T91钢的组织及其力学性能
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作者 顾宝兰 孙浩宇 +2 位作者 安栋 宋明 翟建明 《机械工程材料》 北大核心 2025年第11期25-31,共7页
以541~550℃高温下长期服役(6.2×10^(4)~12×10^(4) h)的T91钢再热器/过热器管段为研究对象,通过多尺度微观结构表征和析出相定量统计,研究了长期服役后T91钢的组织及其力学性能。结果表明:长期服役后,T91钢组织中马氏体板条... 以541~550℃高温下长期服役(6.2×10^(4)~12×10^(4) h)的T91钢再热器/过热器管段为研究对象,通过多尺度微观结构表征和析出相定量统计,研究了长期服役后T91钢的组织及其力学性能。结果表明:长期服役后,T91钢组织中马氏体板条宽化、板条内位错密度降低、亚晶尺寸增加,晶界处析出Laves相,晶界析出相(主要为M_(23)C_(6)和Laves相)呈链状分布并发生粗化。M_(23)C_(6)和Laves相中关键合金元素含量与服役时间呈正相关。长期服役后,T91钢的强度和硬度均下降。服役时间较短(6.2×10^(4) h)时因亚晶尺寸和晶界析出相尺寸最大,T91钢表现出最低的强度和硬度。 展开更多
关键词 长期服役 T91钢 组织老化 LAVES相 定量分析
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Leaching behavior of phosphorous compounds from sewage sludge ash based on quantitative X-ray diffraction analysis 被引量:2
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作者 Pinjing He Xiaotong Zhang +2 位作者 Fan Lü Liming Shao Hua Zhang 《Waste Disposal and Sustainable Energy》 2020年第2期113-125,共13页
Phosphorus(P)is an essential and limited resource.Incineration sewage sludge ash(ISSA)contains a high amount of P,which can be recovered using chemical leaching methods.However,the recovery ratio depends on the specia... Phosphorus(P)is an essential and limited resource.Incineration sewage sludge ash(ISSA)contains a high amount of P,which can be recovered using chemical leaching methods.However,the recovery ratio depends on the speciation of P and the leaching conditions.In this study,hydrochloric acid was used as a leaching agent,and the effects of the hydrochloric acid concentration,leaching time,temperature,and liquid-solid ratio on the P leaching ratio were investigated.Furthermore,the co-leaching of macro-metals Ca,Al,Fe,and Mg was analyzed.The results showed that P leached rapidly within 30 min,where the leaching rate reached more than 80%and then gradually stabilized.The leaching concentrations of Ca and Mg had a significant correlation(correlation coefficient r^(2)>0.90),and both were leached completely.Al and P had similar leaching patterns,where the leaching rates increased initially and then decreased with time at 0.2 mol/L HCl.According to X-ray diffraction analysis and Rietveld refinement,the P in ISSA was mainly present in the forms of Mg_(3)Ca_(3)(PO_(4))_(4) and AlPO_(4).When leached using 0.2 mol/L HCl at 55℃ with a liquid-to-solid ratio of 20 L/kg,the AlPO_(4) and Fe_(3)(H_(2)O)_(3)(PO_(4))_(2) in ISSA dissolved initially and then precipitated on the surface of the solid phase,thereby impeding further P leaching. 展开更多
关键词 Sewage sludge ash Acid leaching Phosphorous speciation quantitative x-ray diffraction analysis Rietveld refinement
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Quantitative analysis results of CE-1 X-ray fluorescence spectrometer ground base experiment
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作者 崔兴柱 王焕玉 +8 位作者 张承模 陈勇 张家宇 彭文溪 曹学蕾 梁小华 汪锦州 高旻 杨家卫 《Chinese Physics C》 SCIE CAS CSCD 北大核心 2008年第1期24-27,共4页
As the nearest celestial body to the earth, the moon has become a hot spot again in astronomy field recently. The element analysis is a much important subject in many lunar projects. Remote X-ray spectrometry plays an... As the nearest celestial body to the earth, the moon has become a hot spot again in astronomy field recently. The element analysis is a much important subject in many lunar projects. Remote X-ray spectrometry plays an important role in the geochemical exploration of the solar bodies. Because of the quasi-vacuum atmosphere on the moon, which has no absorption of X-ray, the X-ray fluorescence analysis is an effective way to determine the elemental abundance of lunar surface. The CE-1 X-ray fluorescence spectrometer (CE-1/XFS) aims to map the major elemental compositions on the lunar surface. This paper describes a method for quantitative analysis of elemental compositions. A series of ground base experiments are done to examine the capability of XFS. The obtained results, which show a reasonable agreement with the certified values at a 30% uncertainty level for major elements, are presented. 展开更多
关键词 x-ray fluorescence elemental abundance lunar surface quantitative analysis
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磁性固相萃取-超高效液相色谱-串联质谱法检测污水中14个芬太尼类毒品 被引量:1
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作者 董洛豪 刘猛 +4 位作者 周婧 王海星 周凯 柯星 范一雷 《药物分析杂志》 北大核心 2025年第7期1221-1232,共12页
目的:建立一种磁性固相萃取-超高效液相色谱-串联质谱(MSPE-UHPLC-MS/MS)快速检测污水中14个芬太尼类毒品的方法。方法:污水样品经新型混合模式弱阳离子交换磁性固相萃取材料Fe_(3)O_(4)@poly(ST/DVB/MA-COOH)净化和浓缩后,采用Waters A... 目的:建立一种磁性固相萃取-超高效液相色谱-串联质谱(MSPE-UHPLC-MS/MS)快速检测污水中14个芬太尼类毒品的方法。方法:污水样品经新型混合模式弱阳离子交换磁性固相萃取材料Fe_(3)O_(4)@poly(ST/DVB/MA-COOH)净化和浓缩后,采用Waters Acquity UPLC HSS T3(150 mm×2.1 mm,1.8μm)色谱柱进行分离,以0.1%甲酸-水溶液(A)和0.1%甲酸-乙腈溶液(B)为流动相,梯度洗脱,柱温40℃,流速0.3 mL·min^(-1),进样量2.5μL,随后进入质谱电喷雾离子源,在多反应检测模式下进行检测。结果:14个芬太尼类毒品质量浓度在0.04~4 ng·L^(-1)范围内线性关系良好(r≥0.9984),检出限(LOD)为0.013 ng·L^(-1),定量限(LOQ)为0.04 ng·L^(-1)。14个分析物在低、中、高3种加标浓度下方法的回收率为85.4%~114.7%,日内精密度(n=6)为2.0%~6.4%,日间精密度(n=3)为0.4%~2.4%。在5份实际污水样品中检测出芬太尼,浓度范围为0.21~0.46 ng·L^(-1)。结论:本方法具有前处理时间短,操作简单,溶剂用量少,灵敏度高和重现性好等优点,适用于污水样品中芬太尼类毒品的高通量筛查和定量分析。 展开更多
关键词 磁性固相萃取 超高效液相色谱-串联质谱 污水 芬太尼类毒品 质谱电喷雾离子源 多反应检测模式 定量分析
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固相萃取-超高效液相色谱-串联三重四极杆质谱法测定水体中18种氨基酸 被引量:1
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作者 梁锦汉 刘则华 +1 位作者 刘婉琼 董燕珊 《质谱学报》 北大核心 2025年第2期242-253,I0006,共13页
在自来水消毒过程中,氨基酸可以与氯、氯胺等消毒剂发生反应,生成具有生物毒性和异味的消毒副产物,需要特别关注。然而,水体中的氨基酸浓度较低,这给检测提出了极高的要求。为此,本研究建立了一种基于固相萃取-超高效液相色谱-串联三重... 在自来水消毒过程中,氨基酸可以与氯、氯胺等消毒剂发生反应,生成具有生物毒性和异味的消毒副产物,需要特别关注。然而,水体中的氨基酸浓度较低,这给检测提出了极高的要求。为此,本研究建立了一种基于固相萃取-超高效液相色谱-串联三重四极杆质谱测定水体中18种氨基酸的方法,并对样品前处理条件和仪器条件进行优化。优化后的最适水样pH 2.8、淋洗液为甲醇-乙酸溶液(1:9,V/V),洗脱液为氨水-甲醇溶液(1:9,V/V),流动相为0.2%甲酸水溶液和含0.2%甲酸的甲醇-乙腈溶液(1:9,V/V)。结果表明,18种氨基酸标准曲线的线性关系良好,相关系数(R^(2))大于0.9913,检出限和定量限分别为0.06~0.23 nmol/L和0.19~0.76 nmol/L,回收率在60.1%~123.2%之间,相对标准偏差为1.7%~18.7%,日间和日内精密度分别为3.7%~7.0%和3.3%~7.1%。采用本方法测定华南地区某自来水厂源水,氨基酸总浓度为300~500 nmol/L,其中,丙氨酸、缬氨酸、天冬氨酸和天冬酰胺的浓度水平占比较高。 展开更多
关键词 固相萃取 氨基酸 定量分析 含氮有机物前体 超高效液相色谱-串联质谱(UPLC-MS/MS)
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基于恰好标度法的消费者评价结合气相色谱-质谱分析植物乳的风味品质
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作者 徐昕蓥 杨傲林 +7 位作者 郭洋帆 王颖 金泽源 张檬 王瑛瑶 王蓓 张秦 李玲楠 《食品科学》 北大核心 2025年第12期240-248,共9页
本实验以5种不同市售植物乳为样品,首先用顶空固相微萃取-气相色谱-质谱(gas chromatography-mass spectrometry,GC-MS)联用技术对植物乳样品的香气成分进行测定,分析不同植物乳样品挥发性成分的差异;随后通过专家感官评价小组定量描述... 本实验以5种不同市售植物乳为样品,首先用顶空固相微萃取-气相色谱-质谱(gas chromatography-mass spectrometry,GC-MS)联用技术对植物乳样品的香气成分进行测定,分析不同植物乳样品挥发性成分的差异;随后通过专家感官评价小组定量描述分析(quantitative descriptive analysis,QDA)找出气味和QDA属性之间相关联特征;结合消费者测评进行惩罚分析,探究各产品优先改进的感官属性及改进方向。通过GC-MS技术在5种不同的植物乳样品中共鉴定出92种挥发性成分,其中香气化合物种类最多、含量最丰富的是醛类、醇类和吡嗪类,这几类挥发性化合物为植物乳提供花生味、苦杏仁味、核桃味等多种坚果味。最后惩罚分析结果表明混合植物乳无需改进,由单一植物来源制成的乳制品需要进一步改进。 展开更多
关键词 顶空固相微萃取-气相色谱-质谱联用技术 定量描述分析 惩罚分析 植物乳 感官属性改进
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X波段相控阵天气雷达多波束扫描模式的观测偏差及订正
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作者 朱家杉 刘黎平 +5 位作者 吴翀 周钦强 刘艳中 高思楠 耿飞 黄辉 《热带气象学报》 北大核心 2025年第5期647-660,共14页
目前,相控阵天气雷达在国内的应用已初具规模,其高效灵活的相控阵电子扫描模式显著提高了雷达的观测效率,使其适应不同的观测任务。然而,相控阵天线性能参数的不稳定性也为数据质控带来了新的挑战。为了检验相控阵雷达多波束扫描模式的... 目前,相控阵天气雷达在国内的应用已初具规模,其高效灵活的相控阵电子扫描模式显著提高了雷达的观测效率,使其适应不同的观测任务。然而,相控阵天线性能参数的不稳定性也为数据质控带来了新的挑战。为了检验相控阵雷达多波束扫描模式的合理性及对数据质量的影响,定量对比了广东省广州市三部X波段双偏振相控阵天气雷达和一部S波段新一代双偏振多普勒天气雷达的观测数据,评估了单波束和多波束扫描模式下灵敏度变化、各个仰角观测量的偏差及其原因。研究结果表明,多波束模式下相控阵雷达的ZH和ZDR观测偏差会随着波束指向偏离天线阵面法向而增大;天线增益在宽发射波束内分布不均匀,造成各个仰角的数据呈现出与发射波束宽度一致的周期波动。通过订正,将多波束模式下不同仰角Z_(H)的平均观测偏差控制到-0.6 dB左右,本研究为相控阵雷达的数据质控和深入应用提供了思路和依据。 展开更多
关键词 相控阵天气雷达 双偏振天气雷达 反射率因子 数据质量 定量分析
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磁共振相位对比血流定量技术定量股骨头旋股内侧动脉深支的可行靠性研究
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作者 廖振洪 杨洁 +2 位作者 刘高元 马春 孙家瑜 《中国实验诊断学》 2025年第4期428-433,共6页
目的探讨磁共振相位对比血流定量(quantitative flow,Q-flow)技术在定量股骨头主要供血动脉——旋股内侧动脉深支血流的可靠性。方法前瞻性收集2024年8月至12月间健康志愿者20例(年龄40.7±12.52岁,女性14例),利用3T磁共振与16通道... 目的探讨磁共振相位对比血流定量(quantitative flow,Q-flow)技术在定量股骨头主要供血动脉——旋股内侧动脉深支血流的可靠性。方法前瞻性收集2024年8月至12月间健康志愿者20例(年龄40.7±12.52岁,女性14例),利用3T磁共振与16通道接收线圈对他们的24侧旋股动脉深支进行了Q-flow成像的定量分析。目标动脉行两次Q-flow扫描,以评价重复扫描一致性。一名13年经验的医师和14年经验的技师独立测量Q-flow图中的目标血管,其结果用于评价两测量者间和测量者两次测量的内部的一致性。使用配对样本t/Wilcoxon检验、组内相关系数(intraclass correlation coefficients,ICC)和Bland-Altman分析评估重复扫描测量者间和测量者的内部的一致性。结果在重复扫描、测量者间和测量者内部的分析中,配对样本t/Wilcoxon检验显示差异无统计学意义(P=0.117~0.962);而相关系数分析中,一致性均较好,ICC值为0.85~1。在Bland-Altman分析中,95%一致性阈值以外的点百分比为4.17%~8.33%。结论高分辨率磁共振Q-flow技术能够可靠的定量股骨头主要供血动脉,为评估股骨头血供变化提供了一种有前景的非侵入性技术手段。 展开更多
关键词 相位对比磁共振成像 股骨头 血供 可靠性 定量分析
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