<span style="font-family:Verdana;">A simple </span><span style="font-family:Verdana;">portable X-Ray Fluorescence (</span><span style="font-family:;" "=&qu...<span style="font-family:Verdana;">A simple </span><span style="font-family:Verdana;">portable X-Ray Fluorescence (</span><span style="font-family:;" "=""><span style="font-family:Verdana;">XRF) spectrometer was successfully used for </span><i><span style="font-family:Verdana;">in-situ</span></i><span style="font-family:Verdana;"> and nondestructive identification of the painting materials in two 15</span><sup><span style="font-family:Verdana;">th</span></sup><span style="font-family:Verdana;"> century icons from the Onufri Museum in Beart, Albania. </span></span><span style="font-family:Verdana;">The spectrometer is based on a low power X-ray tube, a thermoelectrically cooled Si PIN detector and the spectrum acquisition system. It was assembled and adjusted at our laboratory for the investigation of the icons. </span><span style="font-family:Verdana;">A small number of pigments were clearly identified by </span><span style="font-family:Verdana;">X-Ray Fluorescence (</span><span style="font-family:Verdana;">XRF) measurements in both icons. This include</span><span style="font-family:Verdana;">s</span><span style="font-family:;" "=""><span style="font-family:Verdana;"> Lead white for the white color, gold and yellow ochre for the yellow color, red lead, cinnabar and red ochre for the red color, as well as cooper based pigments for the green color. At the same time, the investigation raised some new questions that need further investigations by </span><span style="font-family:Verdana;">the use of additional analytical techniques. The results show that in both</span><span style="font-family:Verdana;"> icons are used similar pigments, which are in accordance with the Byzantine icon painting tradition.</span></span>展开更多
The performance of a portable near-infrared (NIR) spectrometer to determine organic carbon (OC) in marine sediments was evaluated. The NIR reflection spectra of 180 samples in the range 950 - 1650 nm were acquired usi...The performance of a portable near-infrared (NIR) spectrometer to determine organic carbon (OC) in marine sediments was evaluated. The NIR reflection spectra of 180 samples in the range 950 - 1650 nm were acquired using an ultra-compact spectrometer. NIR spectroscopy combined with the partial least squares (PLS) regression and Savitzky-Golay (SG) smoothing was successfully applied to rapid and reagent-free determination of OC. Using the PLS-SG model with 1nd order derivative, 2th polynomial and eleven smoothing points, the root-mean-square errors (RMSEPM) and correlation coefficients (RP,M) of prediction for modeling were 0.073% and 0.894, respectively, the root-mean-square errors (RMSEPV) and correlation coefficients (RP,V) of prediction for validation were 0.075% and 0.883, respectively. Results showed that the small portable NIR instrument achieved well prediction effect for the analysis of OC in marine sediments, which had advantages of rapid, easy to carry and operate suitable for large-scale applications to analyze marine sediments.展开更多
As a simple,fast,and non-destructive measuring technology,dielectric spectroscopy is usually used to analyze the dielectric properties of agricultural products and food,and then to predict the main components of mater...As a simple,fast,and non-destructive measuring technology,dielectric spectroscopy is usually used to analyze the dielectric properties of agricultural products and food,and then to predict the main components of materials.However,the large and expensive vector network analyzers(VNA)with expensive analysis software applied in measuring dielectric properties make research limited to the laboratory.To acquire dielectric spectra in situ,a model for solving relative complex permittivity was derived,and its performance was validated.Then,a low-cost portable dielectric spectrometer with a mini VNA,a Raspberry Pi,and a coaxial probe as core parts was developed over the frequency range of 100-3000 MHz.The stability and accuracy of the developed spectrometer were tested using milk and juice.The results indicated that the relative errors of the model were within±5%for dielectric constant(ε′)and loss factor(ε″).The coefficients of variation of measuredε′andε″by the developed spectrometer at 100-3000 MHz were less than 1%and 2%,respectively.Compared with the dielectric properties obtained by using a commercial dielectric measurement system,the relative errors of measuredε′andε″were within±3.4%and±6.0%,respectively.This study makes fast,non-destructive,and on-site food quality detection using dielectric spectra possible.展开更多
Iodine-131 is a highly toxic and volatile artificial radionuclide that is easily inhaled or ingested by the human body and selectively accumulates in thyroid tissue.With the development of nuclear medicine and nuclear...Iodine-131 is a highly toxic and volatile artificial radionuclide that is easily inhaled or ingested by the human body and selectively accumulates in thyroid tissue.With the development of nuclear medicine and nuclear power plants,the unintended release of ^(131)I has been widely studied,and the in vivo measurement of ^(131)I in the thyroid has become a research hotspot in the field of radiation protection.In recent decades,several methods and devices have been developed for in vivo measurements with respect to different measurement purposes and requirements.In this work,for more accurate determinations of individual ^(131)I in the thyroid in the field,the uncertainties of measurements by using portable gamma spectrometers were reviewed and analyzed,and monitoring strategies for improving the accuracy were proposed and prospected.展开更多
文摘<span style="font-family:Verdana;">A simple </span><span style="font-family:Verdana;">portable X-Ray Fluorescence (</span><span style="font-family:;" "=""><span style="font-family:Verdana;">XRF) spectrometer was successfully used for </span><i><span style="font-family:Verdana;">in-situ</span></i><span style="font-family:Verdana;"> and nondestructive identification of the painting materials in two 15</span><sup><span style="font-family:Verdana;">th</span></sup><span style="font-family:Verdana;"> century icons from the Onufri Museum in Beart, Albania. </span></span><span style="font-family:Verdana;">The spectrometer is based on a low power X-ray tube, a thermoelectrically cooled Si PIN detector and the spectrum acquisition system. It was assembled and adjusted at our laboratory for the investigation of the icons. </span><span style="font-family:Verdana;">A small number of pigments were clearly identified by </span><span style="font-family:Verdana;">X-Ray Fluorescence (</span><span style="font-family:Verdana;">XRF) measurements in both icons. This include</span><span style="font-family:Verdana;">s</span><span style="font-family:;" "=""><span style="font-family:Verdana;"> Lead white for the white color, gold and yellow ochre for the yellow color, red lead, cinnabar and red ochre for the red color, as well as cooper based pigments for the green color. At the same time, the investigation raised some new questions that need further investigations by </span><span style="font-family:Verdana;">the use of additional analytical techniques. The results show that in both</span><span style="font-family:Verdana;"> icons are used similar pigments, which are in accordance with the Byzantine icon painting tradition.</span></span>
文摘The performance of a portable near-infrared (NIR) spectrometer to determine organic carbon (OC) in marine sediments was evaluated. The NIR reflection spectra of 180 samples in the range 950 - 1650 nm were acquired using an ultra-compact spectrometer. NIR spectroscopy combined with the partial least squares (PLS) regression and Savitzky-Golay (SG) smoothing was successfully applied to rapid and reagent-free determination of OC. Using the PLS-SG model with 1nd order derivative, 2th polynomial and eleven smoothing points, the root-mean-square errors (RMSEPM) and correlation coefficients (RP,M) of prediction for modeling were 0.073% and 0.894, respectively, the root-mean-square errors (RMSEPV) and correlation coefficients (RP,V) of prediction for validation were 0.075% and 0.883, respectively. Results showed that the small portable NIR instrument achieved well prediction effect for the analysis of OC in marine sediments, which had advantages of rapid, easy to carry and operate suitable for large-scale applications to analyze marine sediments.
基金financial support provided by the National Natural Science Foundation of China(Grant No.32172308)Startup Foundation for Doctors of Yan'an University(No.YDBK2022-79).
文摘As a simple,fast,and non-destructive measuring technology,dielectric spectroscopy is usually used to analyze the dielectric properties of agricultural products and food,and then to predict the main components of materials.However,the large and expensive vector network analyzers(VNA)with expensive analysis software applied in measuring dielectric properties make research limited to the laboratory.To acquire dielectric spectra in situ,a model for solving relative complex permittivity was derived,and its performance was validated.Then,a low-cost portable dielectric spectrometer with a mini VNA,a Raspberry Pi,and a coaxial probe as core parts was developed over the frequency range of 100-3000 MHz.The stability and accuracy of the developed spectrometer were tested using milk and juice.The results indicated that the relative errors of the model were within±5%for dielectric constant(ε′)and loss factor(ε″).The coefficients of variation of measuredε′andε″by the developed spectrometer at 100-3000 MHz were less than 1%and 2%,respectively.Compared with the dielectric properties obtained by using a commercial dielectric measurement system,the relative errors of measuredε′andε″were within±3.4%and±6.0%,respectively.This study makes fast,non-destructive,and on-site food quality detection using dielectric spectra possible.
基金partially supported by the National Natural Science Foundation of China(No.11775053).
文摘Iodine-131 is a highly toxic and volatile artificial radionuclide that is easily inhaled or ingested by the human body and selectively accumulates in thyroid tissue.With the development of nuclear medicine and nuclear power plants,the unintended release of ^(131)I has been widely studied,and the in vivo measurement of ^(131)I in the thyroid has become a research hotspot in the field of radiation protection.In recent decades,several methods and devices have been developed for in vivo measurements with respect to different measurement purposes and requirements.In this work,for more accurate determinations of individual ^(131)I in the thyroid in the field,the uncertainties of measurements by using portable gamma spectrometers were reviewed and analyzed,and monitoring strategies for improving the accuracy were proposed and prospected.
