Various experimental conditions were described for the vanadium determinationby graphite furnace atomic absorption spectroscopy (GFAAS). The experiments showed that whenatomization took place under the conditions wher...Various experimental conditions were described for the vanadium determinationby graphite furnace atomic absorption spectroscopy (GFAAS). The experiments showed that whenatomization took place under the conditions where the combination of a pyrolytic coating graphitetube and fast raising temperature were used and the temperature was stable, the signal peak shapescould be improved, the sensitivity was enhanced, and the memory effect was removed. The vanadium infood and traditional Chinese medicinal herbs can be accurately determined using the standard curvemethod.展开更多
We develop a high-performance ultraviolet(UV)frequency stabilization technique implemented directly on UV diode lasers by combining the dichroic atomic vapor laser lock and the resonant transfer cavity lock.As an exam...We develop a high-performance ultraviolet(UV)frequency stabilization technique implemented directly on UV diode lasers by combining the dichroic atomic vapor laser lock and the resonant transfer cavity lock.As an example,we demonstrate a stable locking with measured frequency standard deviations of approximately 200 kHz and 300 kHz for 399 nm and 370 nm diode lasers in 20 min.We achieve a long-term frequency drift of no more than 1 MHz for the target 370 nm laser within an hour,which is further verified with fluorescence count rates of a single trapped ^171Yb+ion.We also find strong linear correlations between lock points and environmental factors such as temperature and atmospheric pressure.Our approach provides a simple and stable solution at a relatively low cost,and features flexible control,high feedback bandwidth and minimal power consumption of the target UV laser.展开更多
[Objectives] To establish a method for determining the lead content in lime-preserved eggs, to provide a theoretical basis for the quality control of production enterprises and the sampling and testing of supervision ...[Objectives] To establish a method for determining the lead content in lime-preserved eggs, to provide a theoretical basis for the quality control of production enterprises and the sampling and testing of supervision departments. [Methods] The lead content in lime-preserved eggs was measured by the microwave digestion and flame atomic absorption spectroscopy. [Results] The method had a correlation coefficient of r2=0.998 in the injection concentration range of 0-4 mg/L. The detection limit of the method was 0.008 2 mg/kg. In the range of 0.2 to 1.0 mg/kg addition concentration, the recovery rate of the method was 92.5%-108.0%, and the relative standard deviation(RSD) was <5%. [Conclusions] This method is accurate and reliable, simple and efficient, and is suitable for the detection of lead in lime-preserved eggs.展开更多
New unification theories predict large extra dimensions （LEDs）. If that is the case, gravity would be stronger at short ranges than what Newtonian gravity predicts. LEDs could also have effects at atomic level. In t...New unification theories predict large extra dimensions （LEDs）. If that is the case, gravity would be stronger at short ranges than what Newtonian gravity predicts. LEDs could also have effects at atomic level. In this paper we propose a new method to constrain the size of ‘gravity-only’ LEDs by analysing how these LEDs modify the energy of the atomic transitions 1s-2s and 2s-2p （Lamb shift）, in the particular case of the hydrogen and muonium atoms. We estimate these effects by using Bethe＇s non-relativistic treatment of Lamb shift. In the particular case of three LEDs, which may be a candidate to explain the interaction mechanism of dark matter particles, we have found that current knowledge in atomic spectroscopy could constrain their sizes to less than 10 μm. Although our contributions do not reach the sensitivity given by SN1987a, they are still slightly better than recent constraints given by Inverse Square Law tests of the Eoet-Wash group at Washington University, which gave R3 〈 36.6 μm.展开更多
In the study, the contents of 5 trace elements including Fe, Cu, Mg, Mn and Ca were directly analyzed by flame atomic absorption spectroscopy in Gu- oshangye. The sample was subjected to microwave digestion with HNO3 ...In the study, the contents of 5 trace elements including Fe, Cu, Mg, Mn and Ca were directly analyzed by flame atomic absorption spectroscopy in Gu- oshangye. The sample was subjected to microwave digestion with HNO3 and H2O2, and detected by the standard curve method. The results showed that Guoshangye contained abundant trace elements which rates of these trace elements were in the curacy and satisfactory. were necessary for human. The recovery range of 96%-103%. The method is ac-展开更多
The laser induced breakdown spectroscopy(LIBS) is an element analysis technique with the advantages of real time detection,simultaneous multi-element identification,and in-situ and stand-off capacities.To evaluate its...The laser induced breakdown spectroscopy(LIBS) is an element analysis technique with the advantages of real time detection,simultaneous multi-element identification,and in-situ and stand-off capacities.To evaluate its potential of ocean applications,in this paper,the time resolved laser-induced breakdown spectroscopy for calcium concentration detection in water is investigated.With the optimum experimental parameters,the plasma emission lifetime is determined to be about 500 ns with 532 nm laser excitation,and 1000 ns with 1064 nm laser excitation.The lowest detection concentration of 50 ppm is achieved for calcium detection in CaCl2 water solution using the 532 nm LIBS.Even better detection sensitivity is achieved using the 1064 nm LIBS,and the resulted lowest detection concentration of calcium is 25 ppm.The results suggest that it is feasible to develop LIBS as an on-line sensor for metal element monitoring in the sea.展开更多
The influence of the energy of femtosecond laser pulses on the intensity of Fe I （371.99 nm） emission line and the continuous spectrum of the plasma generated on the surface of Fe^3＋ water solution by a Ti： sapphi...The influence of the energy of femtosecond laser pulses on the intensity of Fe I （371.99 nm） emission line and the continuous spectrum of the plasma generated on the surface of Fe^3＋ water solution by a Ti： sapphire laser radiation with pulse duration 〈45 fs and energies up to 7 mJ is determined. A calibration curve was obtained for Fe3＋ concentration range from 0.5 g/L to the limit of detection in water solution, and its saturation was detected for concentrations above 0.25 g/L, which is ascribed to self-absorption. The 3σ- limit of detection obtained for Fe in water solution is 2.6 mg/L in the case of 7 mJ laser pulse energy. It is found that an increase of laser pulse energy insignificantly affects on LOD in the time-resolved LIBS and leads to a slight improvement of the limit of detection.展开更多
The adsorption behavior of multiwalled carbon nanotubes （MWNTs） toward heavy elements has been investigated systemically, and a new method has been developed for the determination of trace elements in water samples ...The adsorption behavior of multiwalled carbon nanotubes （MWNTs） toward heavy elements has been investigated systemically, and a new method has been developed for the determination of trace elements in water samples based on preconcentration with mini-column packed with MWNTs prior to its determination by flame atomic absorption spectrometry （FAAS） The recommended parameters of proposed method influencing the preconcentration of the analytes, such as pH of the sample, sample flow rate and volume, elute solution and interfering ions, have been used. Under the optimized conditions, the calibration graphs were linear with the correlation coefficient range 0.9981-0.9995. According to the results, the metals were found 0.019-0.051, 0.011-0.031, 0.00-0.081, 0.00-0.0002, 0.007-0.0925, 0.00-0.0104 μg/L in water samples for Pb, Mn, Zn, Cd, Fe, Cu respectively. The percentage relative standard deviation （%RSD） for five replicate samples were 〈 5% in all cases. The method has been successfully applied to the determination of trace elements in some environmental samples with satisfactory results.展开更多
An innovative method for the ultrasensitive detection of mercury by solution anode glow discharge atomic emission spectroscopy(SAGD-AES) coupled with hydride generation(HG) was first investigated.In this method,the me...An innovative method for the ultrasensitive detection of mercury by solution anode glow discharge atomic emission spectroscopy(SAGD-AES) coupled with hydride generation(HG) was first investigated.In this method,the mercury vapor generated by the HG was transmitted to the SAGD through the miniature hollow tungsten tube for excitation and detected by a miniaturized spectrograph.A thorough parametric evaluation of the HG and SAGD system was performed,including the type and concentration of ca rrier acid,He flow rate,concentrations of NaBH4,discha rge current and discharge gap.Under optimal operating conditions,the detection limit for Hg^(2+) achieved 0.03 μg/L,with a relative standard deviation of 1.1% at the Hg^(2+) concentration of 5 μg/L.Moreover,the correlation coefficient of the calibration curve was 0.9996 in the range between 0.1 and 10 μg/L.The accuracy and practicability of HG-SAGD-AES were verified by measuring GBW09101 b(human hair),GBW10029(fish),soil and rice samples.The results showed good agreement with the certified values and values from direct mercury analyzer(DMA).展开更多
Experimental investigations were conducted in this study to explore the effect of magnetization on water sample properties and to envisage whether the effect is beneficial for mercury detection in a sample of water or...Experimental investigations were conducted in this study to explore the effect of magnetization on water sample properties and to envisage whether the effect is beneficial for mercury detection in a sample of water or not. Subjecting the water sample to 0.3 Tesla magnetic field for 14 hours led to instantaneous effects on the examined water properties, where a reduction in the values of pH （7%） and interfacial tension （0.2%） was observed, whereas an increase （8%） in water electrical conductivity was recorded. Similar behaviours with slight changes in trend were observed after storing the samples for six days, which indicates a creation of permanent effects. Other experiments were conducted to explore the impact of magnetizing water sample containing inorganic mercury prior to detection by emission spectroscopy. Samples were prepared with different mercury concentrations and derivatized by using tin chloride （SnCI2）. The generated mercury vapour species were transported with aid of carrier gas into a dielectric barrier discharge plasma atomizer, in which the mercury signal at 253.65 nm was recorded. The results have shown 3.5%-7.5% increase in the signal intensities recorded for the magnetized samples, mostly attributed to a reduction in the sample surface tension and other reasons, which facilitates analyte derivatization.展开更多
An improved method has been developed for enriching and determining trace In,Pt,Sn,Co,Hg,Pb,Ni, Bi,Pd,Cu and Ag in high-purity gallium.Sample was treated by PDM(partial dissolution of matrix)with HCl(11mol/L)-HNO_3(0....An improved method has been developed for enriching and determining trace In,Pt,Sn,Co,Hg,Pb,Ni, Bi,Pd,Cu and Ag in high-purity gallium.Sample was treated by PDM(partial dissolution of matrix)with HCl(11mol/L)-HNO_3(0.5mol/L)to a small residue of which Ga was then removed by extraction with 1 ml isopropyl ether.The concentrated impurities were determined by AES procedure.The recoveries for the ele- ments at the range of 0.02～0.2 μg are 95～103％;the relative standard deviations for determined impurities overa rangeofn.10^(-7)～n·10^(-8)％ are 4.3～12％;the detection limit of most elements can reach n·10^(-7)～ n·10^(-8)％ level with the exception of Hg and Pt.This method has been successfully used to analyze many sam- ples sent by factories and institutes.展开更多
The determination of copper by MIP-AES was investigated in detail. Aqueous samples were introduced from an ultrasonic nebulizer and the solvent was removed by a desolvation device before introduction of the aerosol in...The determination of copper by MIP-AES was investigated in detail. Aqueous samples were introduced from an ultrasonic nebulizer and the solvent was removed by a desolvation device before introduction of the aerosol into the MIP. The desolvation system consisted of a condenser associated with a concentrated H2SO4 absorption cell. Various experimental conditions and interferences from easily ionised elements (EIEs) were also studied and some practical samples were analyzed.展开更多
The analysis of trace elements in human tooth for use as biomarkers continues to generate considerable interest in environmental and bioanalytical studies, medical diagnostic and forensic science. This study investiga...The analysis of trace elements in human tooth for use as biomarkers continues to generate considerable interest in environmental and bioanalytical studies, medical diagnostic and forensic science. This study investigated concentrations of essential and toxic elements (Zn, Cu, Pb, Ni, Co and Cd) using flame atomic absorption spectroscopy (FAAS) and (Na and K) flame atomic emission spectroscopy (FAES) in human tooth obtained from Misan province, Iraq. The influence of smoking habits and born children on the levels of trace elements in additional to dental erosion by some beverages in the tooth samples were investigated. The overall of mean concentrations of (Zn 185.2 ppm, Cu 36.11 ppm, Pb 18.63 ppm, Ni 13.44 ppm, Co 3.45 ppm, and Cd 0.58 ppm, Na 11.683 ppm and K 115.27 ppm), (Zn 178.243 ppm, Cu 35.877 ppm, Pb 15.64 ppm, Ni 12.89 ppm, Co 3.421 ppm, Cd 0.455 ppm, Na 11,558.04 ppm and K 114.04 ppm) in smokers and non-smokers tooth groups respectively, (Zn 81.12 ppm, Cu 24.37 ppm, Pb 11.18 ppm, Ni 13.68 ppm, Co 3.32 ppm, Cd 0.44 ppm, Na 8227 ppm and K 76.42 ppm), (Zn 80.58 ppm, Cu 24.30 ppm, Pb 10.86 ppm, Ni 12.74 ppm, Co 2.71 ppm, Cd 0.23 ppm, Na 8165 ppm and K 72.80 ppm) in mothers and wives tooth groups respectively. However the w/w% loss of tooth immersed in following order of beverages (green tea, black tea, cinnamon, hibiscus, vinegar and citrus aurantifolia (9.09, 9.68, 12.36, 15.01, 16.77 and 17.38), (8.19, 8.25, 9.76, 13.37, 14.02 and 15.33) in smokers and non-smokers groups respectively, (11.25, 11.47, 13.30, 15.75, 19.58, and 20.91), (8.31, 7.96, 11.39, 13.49, 17.40, and 17.67) in mothers and wives groups respectively. However, there is a statistically significant variance found Zn (t<sub>cal</sub> 5.029, t<sub>tab</sub> 2.131), Pb (t<sub>cal</sub> 4.8538, t<sub>tab</sub> 2.131), Ni (t<sub>ca</sub><sub>l</sub> 5.243, t<sub>tab</sub> 2.131), Cd (t<sub>cal</sub> 3.9062, t<sub>tab</sub> 2.131) and Na (t<sub>cal</sub> 3.0832, t<sub>tab</sub> 2.131) between smokers and non-smokers tooth groups. However, the Co (t<sub>cal</sub> 2.7403, t<sub>tab</sub> 2.131) also shows statistically significant variance between mothers and wives groups. There is no statistically significant variance in w/w% loss after immersed the tooth in some beverages but in general it was higher in smokers than non-smokers and in mothers higher than wives.展开更多
A velocity-selective spectroscopy technique for studying the spectra of Rydberg gases is presented. This method provides high-resolution spectrum measurements. We present experimental results for a ladder system 6S1/2...A velocity-selective spectroscopy technique for studying the spectra of Rydberg gases is presented. This method provides high-resolution spectrum measurements. We present experimental results for a ladder system 6S1/2→ 6P3/2→ nS（D）electromagnetically-induced transparency involving highly-excited Rydberg states. Based on a radio-frequency modulation technique, we measure the hyperfine structure splitting of intermediate states and the fine structure splitting of Rydberg states in a room temperature ^133Cs vapor cell. The experimental data and theoretical predictions show excellent agreement.展开更多
Standard perturbation theory is employed to calculate the mass shifts of the 2^(1)S_(0)-^(3)S_(1)and 2^(3)S_(1)-2^(3)P_(J)transitions for^(4,6,8)He.High-precision results are obtained for the mass shifts in the isotop...Standard perturbation theory is employed to calculate the mass shifts of the 2^(1)S_(0)-^(3)S_(1)and 2^(3)S_(1)-2^(3)P_(J)transitions for^(4,6,8)He.High-precision results are obtained for the mass shifts in the isotope pairs 6He-4He and 8He-4He,with uncertainties below 1 part per million(ppm).Our analysis provides a complete set of isotope-shift results and systematically examines their sensitivity to nuclear charge-radius differences.Once experimental measurements reach a precision comparable to that of the calculated mass shifts,the squared differences of nuclear charge radii can be determined with an accuracy of approximately 0.4%-0.6%,representing an order-of-magnitude improvement over current values.展开更多
The factors that influence the colorimetric gene detection of gold label silver stain and improve the detection signals were studied. The influence of amino DNA probes and thiol DNA modified gold nanoparticles was inv...The factors that influence the colorimetric gene detection of gold label silver stain and improve the detection signals were studied. The influence of amino DNA probes and thiol DNA modified gold nanoparticles was investigated based on a sandwich hybridization system. An increase in amino probe concentration brought about an increase in hybridization signal which reached a threshold corresponding to the saturated concentration of amino probes bounded onto a glass slide surface. Since the steric hindrance effect of nanoparticles was dominant over the influence of a surface area, the bigger gold nanoparticles led to weaker hybridization signals. The hybridization efficiency enhanced significantly with the increase of the thiol DNA modified nanoparticle concentrations. Experimental results showed that 125 μmol/L of the amino DNA probe concentration, 15 nm of the gold nanoparticle diameter, and 4.07 nmol/L of the thiol DNA modified gold nanoparticle concentration were optimal for the detection system. The hybridization signals can be improved remarkably by choosing optimal hybridization conditions.展开更多
The production of colored flames is the primary purpose of military signaling, projectile tracing, and illuminating devices. Certain elements and compounds when heated to high temperature have the unique property of e...The production of colored flames is the primary purpose of military signaling, projectile tracing, and illuminating devices. Certain elements and compounds when heated to high temperature have the unique property of emitting lines or narrow bands in the visible region(380-780 nm). This study, reports on the development of novel yellow colored flame compositions with enhanced spectral performance in terms of luminous intensity, and color quality to standard Russian yellow tracer. The light intensity and the imprint spectra of developed yellow flares were measured using digital luxmeter and UV e Vis. spectrometer respectively. The main giving of this study is that the light intensity, and color quality of Russian yellow tracer were improved by 287%, and 170% respectively. This was accomplished by means of optimizing the ratio of novel binder to color source using aluminum metal fuel. Aluminumbased formulations were found to maximize the formation of yellow reactive emitting specimens, and to eliminate any interfering incandescent emission resulted from Mg O. Quantification of yellow color emitting specimens in the combustion gaseous products was achieved using chemical equilibrium thermodynamic code named ICT(Institute of Chemical Technology in Germany, Virgin 2008); in an attempt to judge the light quality. This improvement in yellow flare performance established the rule that the emission intensity increases as the reaction temperature increases. In the meantime upper limit of temperature was avoided to maximize the color quality.展开更多
We investigate theoretically two-photon absorption spectroscopy modified by a control field in a confined Y-type four-level system. Dicke-narrowing effect occurs both in two-photon absorption lines and the dips of tra...We investigate theoretically two-photon absorption spectroscopy modified by a control field in a confined Y-type four-level system. Dicke-narrowing effect occurs both in two-photon absorption lines and the dips of transparency against two-photon absorption due to enhanced contribution of slow atoms. We also find that the suppression and the enhancement of two-photon absorption can be modified by changing the strength of the control field and the detuning of three laser fields. This control of two-photon absorption may have some applications in information processing and optical devices.展开更多
Atomic spectroscopy serves as the basis for quantum precision measurements,where frequency-stabilized lasers are crucial for obtaining accurate atomic spectra.This work introduces a compact laser frequency stabilizati...Atomic spectroscopy serves as the basis for quantum precision measurements,where frequency-stabilized lasers are crucial for obtaining accurate atomic spectra.This work introduces a compact laser frequency stabilization system that employs a multifunctional metasurface to adjust the polarization,amplitude,and propagation direction of incident light.By combining with a Rb atomic vapor cell,the system achieves a tunable sub-Doppler spectrum for laser frequency stabilization.The experimental result demonstrates that a laser frequency stability of 3×10−11 is attained from 1 to 200 s at 780 nm with the input power at 20µW.The devices hold significant potential for compactness,integration,and mass production,making them highly suitable for quantum measurement applications.展开更多
The phylogenetic relationship for classification traits and eight mineral elements in brown rice （Oryza sativa L.） from Yunnan Province in China was carried out using microwave assisted digestion followed by inducti...The phylogenetic relationship for classification traits and eight mineral elements in brown rice （Oryza sativa L.） from Yunnan Province in China was carried out using microwave assisted digestion followed by inductively coupled plasma atomic emission spectroscopy, and the analytical procedures were carefully controlled and validated. In general, the results show that the mean levels of K, Ca, Mg, Fe and Cu in brown rice for 789 accessions of rice landraces was distinctly lower than that of improved cultivars. They further demonstrate that Ca plays an important role in the differentiation of subspecies indica-japonica, especially to enhance adaptation of cold stress, and that five mineral elements in brown rice enhance the eurytopicity from landrace to improved cultivar. Hierarchical cluster analysis, using average linkage from SPSS software based on eight mineral elements in brown rice, showed that Yunnan rice could be grouped into rice landrace and improved cultivar, with the rice landrace being further clustered into five subgroups, and that, interestingly, purple rice does not cluster with either of the groups. Our present data confirm that indica is the closest relative of late rice and white rice, and that they constitute rice landraces together, whereas japonica is the closest relatives of non-nuda, early-mid and glutinous rice. It is further shown that japonica, non-nuda, early-mid, glutinous, white and red rice might be more primitive than indica, nuda, late, non-glutinous and purple rice, respectively.展开更多
文摘Various experimental conditions were described for the vanadium determinationby graphite furnace atomic absorption spectroscopy (GFAAS). The experiments showed that whenatomization took place under the conditions where the combination of a pyrolytic coating graphitetube and fast raising temperature were used and the temperature was stable, the signal peak shapescould be improved, the sensitivity was enhanced, and the memory effect was removed. The vanadium infood and traditional Chinese medicinal herbs can be accurately determined using the standard curvemethod.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11704408 and 91836106)the Beijing Natural Science Foundation,China(Grant No.Z180013)the Joint Fund of the Ministry of Education,China(Grant No.6141A020333xx).
文摘We develop a high-performance ultraviolet(UV)frequency stabilization technique implemented directly on UV diode lasers by combining the dichroic atomic vapor laser lock and the resonant transfer cavity lock.As an example,we demonstrate a stable locking with measured frequency standard deviations of approximately 200 kHz and 300 kHz for 399 nm and 370 nm diode lasers in 20 min.We achieve a long-term frequency drift of no more than 1 MHz for the target 370 nm laser within an hour,which is further verified with fluorescence count rates of a single trapped ^171Yb+ion.We also find strong linear correlations between lock points and environmental factors such as temperature and atmospheric pressure.Our approach provides a simple and stable solution at a relatively low cost,and features flexible control,high feedback bandwidth and minimal power consumption of the target UV laser.
文摘[Objectives] To establish a method for determining the lead content in lime-preserved eggs, to provide a theoretical basis for the quality control of production enterprises and the sampling and testing of supervision departments. [Methods] The lead content in lime-preserved eggs was measured by the microwave digestion and flame atomic absorption spectroscopy. [Results] The method had a correlation coefficient of r2=0.998 in the injection concentration range of 0-4 mg/L. The detection limit of the method was 0.008 2 mg/kg. In the range of 0.2 to 1.0 mg/kg addition concentration, the recovery rate of the method was 92.5%-108.0%, and the relative standard deviation(RSD) was <5%. [Conclusions] This method is accurate and reliable, simple and efficient, and is suitable for the detection of lead in lime-preserved eggs.
基金Project supported by the National Natural Science Foundation of China (Grant No 10475114)the Foundation of Minor Planets of Purple Mountain Observatory, China
文摘New unification theories predict large extra dimensions （LEDs）. If that is the case, gravity would be stronger at short ranges than what Newtonian gravity predicts. LEDs could also have effects at atomic level. In this paper we propose a new method to constrain the size of ‘gravity-only’ LEDs by analysing how these LEDs modify the energy of the atomic transitions 1s-2s and 2s-2p （Lamb shift）, in the particular case of the hydrogen and muonium atoms. We estimate these effects by using Bethe＇s non-relativistic treatment of Lamb shift. In the particular case of three LEDs, which may be a candidate to explain the interaction mechanism of dark matter particles, we have found that current knowledge in atomic spectroscopy could constrain their sizes to less than 10 μm. Although our contributions do not reach the sensitivity given by SN1987a, they are still slightly better than recent constraints given by Inverse Square Law tests of the Eoet-Wash group at Washington University, which gave R3 〈 36.6 μm.
基金Supported by the Research Project for Postgraduate Students of Minzu University of China in 2015Scientific and Technological Cooperation Planning Project of Guizhou Province(QKJ LH[2015]7265)~~
文摘In the study, the contents of 5 trace elements including Fe, Cu, Mg, Mn and Ca were directly analyzed by flame atomic absorption spectroscopy in Gu- oshangye. The sample was subjected to microwave digestion with HNO3 and H2O2, and detected by the standard curve method. The results showed that Guoshangye contained abundant trace elements which rates of these trace elements were in the curacy and satisfactory. were necessary for human. The recovery range of 96%-103%. The method is ac-
基金supported by the National High Technology Research and Development Program of China (No.2006AA09Z243)the Natural Science Foundation of Shandong Province (No.Y2006A26)
文摘The laser induced breakdown spectroscopy(LIBS) is an element analysis technique with the advantages of real time detection,simultaneous multi-element identification,and in-situ and stand-off capacities.To evaluate its potential of ocean applications,in this paper,the time resolved laser-induced breakdown spectroscopy for calcium concentration detection in water is investigated.With the optimum experimental parameters,the plasma emission lifetime is determined to be about 500 ns with 532 nm laser excitation,and 1000 ns with 1064 nm laser excitation.The lowest detection concentration of 50 ppm is achieved for calcium detection in CaCl2 water solution using the 532 nm LIBS.Even better detection sensitivity is achieved using the 1064 nm LIBS,and the resulted lowest detection concentration of calcium is 25 ppm.The results suggest that it is feasible to develop LIBS as an on-line sensor for metal element monitoring in the sea.
基金supported by the Russian Science Foundation(agreement#14-50-00034)(measurements of limit of detection)Russian Foundation for Basic Research(NK 15-32-20878/15)obtained in the frame of "Organization of Scientific Research"in the Far Eastern Federal University supported by Ministry of Education and Science of Russian Federation
文摘The influence of the energy of femtosecond laser pulses on the intensity of Fe I （371.99 nm） emission line and the continuous spectrum of the plasma generated on the surface of Fe^3＋ water solution by a Ti： sapphire laser radiation with pulse duration 〈45 fs and energies up to 7 mJ is determined. A calibration curve was obtained for Fe3＋ concentration range from 0.5 g/L to the limit of detection in water solution, and its saturation was detected for concentrations above 0.25 g/L, which is ascribed to self-absorption. The 3σ- limit of detection obtained for Fe in water solution is 2.6 mg/L in the case of 7 mJ laser pulse energy. It is found that an increase of laser pulse energy insignificantly affects on LOD in the time-resolved LIBS and leads to a slight improvement of the limit of detection.
文摘The adsorption behavior of multiwalled carbon nanotubes （MWNTs） toward heavy elements has been investigated systemically, and a new method has been developed for the determination of trace elements in water samples based on preconcentration with mini-column packed with MWNTs prior to its determination by flame atomic absorption spectrometry （FAAS） The recommended parameters of proposed method influencing the preconcentration of the analytes, such as pH of the sample, sample flow rate and volume, elute solution and interfering ions, have been used. Under the optimized conditions, the calibration graphs were linear with the correlation coefficient range 0.9981-0.9995. According to the results, the metals were found 0.019-0.051, 0.011-0.031, 0.00-0.081, 0.00-0.0002, 0.007-0.0925, 0.00-0.0104 μg/L in water samples for Pb, Mn, Zn, Cd, Fe, Cu respectively. The percentage relative standard deviation （%RSD） for five replicate samples were 〈 5% in all cases. The method has been successfully applied to the determination of trace elements in some environmental samples with satisfactory results.
基金the Instrument Development Project of the Chinese Academy of Sciences(No.YZ201539)the National Natural Science Foundation of China(No.21175145)Shanghai Technical Platform for Testing on Inorganic Materials(No.19DZ2290700)。
文摘An innovative method for the ultrasensitive detection of mercury by solution anode glow discharge atomic emission spectroscopy(SAGD-AES) coupled with hydride generation(HG) was first investigated.In this method,the mercury vapor generated by the HG was transmitted to the SAGD through the miniature hollow tungsten tube for excitation and detected by a miniaturized spectrograph.A thorough parametric evaluation of the HG and SAGD system was performed,including the type and concentration of ca rrier acid,He flow rate,concentrations of NaBH4,discha rge current and discharge gap.Under optimal operating conditions,the detection limit for Hg^(2+) achieved 0.03 μg/L,with a relative standard deviation of 1.1% at the Hg^(2+) concentration of 5 μg/L.Moreover,the correlation coefficient of the calibration curve was 0.9996 in the range between 0.1 and 10 μg/L.The accuracy and practicability of HG-SAGD-AES were verified by measuring GBW09101 b(human hair),GBW10029(fish),soil and rice samples.The results showed good agreement with the certified values and values from direct mercury analyzer(DMA).
文摘Experimental investigations were conducted in this study to explore the effect of magnetization on water sample properties and to envisage whether the effect is beneficial for mercury detection in a sample of water or not. Subjecting the water sample to 0.3 Tesla magnetic field for 14 hours led to instantaneous effects on the examined water properties, where a reduction in the values of pH （7%） and interfacial tension （0.2%） was observed, whereas an increase （8%） in water electrical conductivity was recorded. Similar behaviours with slight changes in trend were observed after storing the samples for six days, which indicates a creation of permanent effects. Other experiments were conducted to explore the impact of magnetizing water sample containing inorganic mercury prior to detection by emission spectroscopy. Samples were prepared with different mercury concentrations and derivatized by using tin chloride （SnCI2）. The generated mercury vapour species were transported with aid of carrier gas into a dielectric barrier discharge plasma atomizer, in which the mercury signal at 253.65 nm was recorded. The results have shown 3.5%-7.5% increase in the signal intensities recorded for the magnetized samples, mostly attributed to a reduction in the sample surface tension and other reasons, which facilitates analyte derivatization.
文摘An improved method has been developed for enriching and determining trace In,Pt,Sn,Co,Hg,Pb,Ni, Bi,Pd,Cu and Ag in high-purity gallium.Sample was treated by PDM(partial dissolution of matrix)with HCl(11mol/L)-HNO_3(0.5mol/L)to a small residue of which Ga was then removed by extraction with 1 ml isopropyl ether.The concentrated impurities were determined by AES procedure.The recoveries for the ele- ments at the range of 0.02～0.2 μg are 95～103％;the relative standard deviations for determined impurities overa rangeofn.10^(-7)～n·10^(-8)％ are 4.3～12％;the detection limit of most elements can reach n·10^(-7)～ n·10^(-8)％ level with the exception of Hg and Pt.This method has been successfully used to analyze many sam- ples sent by factories and institutes.
基金Supported by the Natinoal Natural Science Foundation of China.
文摘The determination of copper by MIP-AES was investigated in detail. Aqueous samples were introduced from an ultrasonic nebulizer and the solvent was removed by a desolvation device before introduction of the aerosol into the MIP. The desolvation system consisted of a condenser associated with a concentrated H2SO4 absorption cell. Various experimental conditions and interferences from easily ionised elements (EIEs) were also studied and some practical samples were analyzed.
文摘The analysis of trace elements in human tooth for use as biomarkers continues to generate considerable interest in environmental and bioanalytical studies, medical diagnostic and forensic science. This study investigated concentrations of essential and toxic elements (Zn, Cu, Pb, Ni, Co and Cd) using flame atomic absorption spectroscopy (FAAS) and (Na and K) flame atomic emission spectroscopy (FAES) in human tooth obtained from Misan province, Iraq. The influence of smoking habits and born children on the levels of trace elements in additional to dental erosion by some beverages in the tooth samples were investigated. The overall of mean concentrations of (Zn 185.2 ppm, Cu 36.11 ppm, Pb 18.63 ppm, Ni 13.44 ppm, Co 3.45 ppm, and Cd 0.58 ppm, Na 11.683 ppm and K 115.27 ppm), (Zn 178.243 ppm, Cu 35.877 ppm, Pb 15.64 ppm, Ni 12.89 ppm, Co 3.421 ppm, Cd 0.455 ppm, Na 11,558.04 ppm and K 114.04 ppm) in smokers and non-smokers tooth groups respectively, (Zn 81.12 ppm, Cu 24.37 ppm, Pb 11.18 ppm, Ni 13.68 ppm, Co 3.32 ppm, Cd 0.44 ppm, Na 8227 ppm and K 76.42 ppm), (Zn 80.58 ppm, Cu 24.30 ppm, Pb 10.86 ppm, Ni 12.74 ppm, Co 2.71 ppm, Cd 0.23 ppm, Na 8165 ppm and K 72.80 ppm) in mothers and wives tooth groups respectively. However the w/w% loss of tooth immersed in following order of beverages (green tea, black tea, cinnamon, hibiscus, vinegar and citrus aurantifolia (9.09, 9.68, 12.36, 15.01, 16.77 and 17.38), (8.19, 8.25, 9.76, 13.37, 14.02 and 15.33) in smokers and non-smokers groups respectively, (11.25, 11.47, 13.30, 15.75, 19.58, and 20.91), (8.31, 7.96, 11.39, 13.49, 17.40, and 17.67) in mothers and wives groups respectively. However, there is a statistically significant variance found Zn (t<sub>cal</sub> 5.029, t<sub>tab</sub> 2.131), Pb (t<sub>cal</sub> 4.8538, t<sub>tab</sub> 2.131), Ni (t<sub>ca</sub><sub>l</sub> 5.243, t<sub>tab</sub> 2.131), Cd (t<sub>cal</sub> 3.9062, t<sub>tab</sub> 2.131) and Na (t<sub>cal</sub> 3.0832, t<sub>tab</sub> 2.131) between smokers and non-smokers tooth groups. However, the Co (t<sub>cal</sub> 2.7403, t<sub>tab</sub> 2.131) also shows statistically significant variance between mothers and wives groups. There is no statistically significant variance in w/w% loss after immersed the tooth in some beverages but in general it was higher in smokers than non-smokers and in mothers higher than wives.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61475091 and 61227902)the National Key Research and Development Program of China(Grant No.2017YFA0304502)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi,China(Grant No.2017101)
文摘A velocity-selective spectroscopy technique for studying the spectra of Rydberg gases is presented. This method provides high-resolution spectrum measurements. We present experimental results for a ladder system 6S1/2→ 6P3/2→ nS（D）electromagnetically-induced transparency involving highly-excited Rydberg states. Based on a radio-frequency modulation technique, we measure the hyperfine structure splitting of intermediate states and the fine structure splitting of Rydberg states in a room temperature ^133Cs vapor cell. The experimental data and theoretical predictions show excellent agreement.
基金supported by the National Natural Science Foundation of China(Grant Nos.12204412,12274423,12174402,12393821,and 12004124)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB0920100 and XDB0920101)support from the Natural Sciences and Engineering Research Council of Canada.All calculations were performed on the APM-Theoretical Computing Cluster(APM-TCC).
文摘Standard perturbation theory is employed to calculate the mass shifts of the 2^(1)S_(0)-^(3)S_(1)and 2^(3)S_(1)-2^(3)P_(J)transitions for^(4,6,8)He.High-precision results are obtained for the mass shifts in the isotope pairs 6He-4He and 8He-4He,with uncertainties below 1 part per million(ppm).Our analysis provides a complete set of isotope-shift results and systematically examines their sensitivity to nuclear charge-radius differences.Once experimental measurements reach a precision comparable to that of the calculated mass shifts,the squared differences of nuclear charge radii can be determined with an accuracy of approximately 0.4%-0.6%,representing an order-of-magnitude improvement over current values.
文摘The factors that influence the colorimetric gene detection of gold label silver stain and improve the detection signals were studied. The influence of amino DNA probes and thiol DNA modified gold nanoparticles was investigated based on a sandwich hybridization system. An increase in amino probe concentration brought about an increase in hybridization signal which reached a threshold corresponding to the saturated concentration of amino probes bounded onto a glass slide surface. Since the steric hindrance effect of nanoparticles was dominant over the influence of a surface area, the bigger gold nanoparticles led to weaker hybridization signals. The hybridization efficiency enhanced significantly with the increase of the thiol DNA modified nanoparticle concentrations. Experimental results showed that 125 μmol/L of the amino DNA probe concentration, 15 nm of the gold nanoparticle diameter, and 4.07 nmol/L of the thiol DNA modified gold nanoparticle concentration were optimal for the detection system. The hybridization signals can be improved remarkably by choosing optimal hybridization conditions.
基金funding the research project entitled“Enhanced Visible Tracers for Illumination and Tracking”
文摘The production of colored flames is the primary purpose of military signaling, projectile tracing, and illuminating devices. Certain elements and compounds when heated to high temperature have the unique property of emitting lines or narrow bands in the visible region(380-780 nm). This study, reports on the development of novel yellow colored flame compositions with enhanced spectral performance in terms of luminous intensity, and color quality to standard Russian yellow tracer. The light intensity and the imprint spectra of developed yellow flares were measured using digital luxmeter and UV e Vis. spectrometer respectively. The main giving of this study is that the light intensity, and color quality of Russian yellow tracer were improved by 287%, and 170% respectively. This was accomplished by means of optimizing the ratio of novel binder to color source using aluminum metal fuel. Aluminumbased formulations were found to maximize the formation of yellow reactive emitting specimens, and to eliminate any interfering incandescent emission resulted from Mg O. Quantification of yellow color emitting specimens in the combustion gaseous products was achieved using chemical equilibrium thermodynamic code named ICT(Institute of Chemical Technology in Germany, Virgin 2008); in an attempt to judge the light quality. This improvement in yellow flare performance established the rule that the emission intensity increases as the reaction temperature increases. In the meantime upper limit of temperature was avoided to maximize the color quality.
基金supported by the National Natural Science Foundation of China (No. 10874139) the Major Program of Science Foundation of Xi’an University of Arts and Science
文摘We investigate theoretically two-photon absorption spectroscopy modified by a control field in a confined Y-type four-level system. Dicke-narrowing effect occurs both in two-photon absorption lines and the dips of transparency against two-photon absorption due to enhanced contribution of slow atoms. We also find that the suppression and the enhancement of two-photon absorption can be modified by changing the strength of the control field and the detuning of three laser fields. This control of two-photon absorption may have some applications in information processing and optical devices.
基金supported by the Fundamental Research Funds for the Central Universities(No.KG21008401).
文摘Atomic spectroscopy serves as the basis for quantum precision measurements,where frequency-stabilized lasers are crucial for obtaining accurate atomic spectra.This work introduces a compact laser frequency stabilization system that employs a multifunctional metasurface to adjust the polarization,amplitude,and propagation direction of incident light.By combining with a Rb atomic vapor cell,the system achieves a tunable sub-Doppler spectrum for laser frequency stabilization.The experimental result demonstrates that a laser frequency stability of 3×10−11 is attained from 1 to 200 s at 780 nm with the input power at 20µW.The devices hold significant potential for compactness,integration,and mass production,making them highly suitable for quantum measurement applications.
基金Supported by the National Natural Science Foundation of China (30660092)the Cooperation Program between Province and Zhejiang University from Yunnan Provincial Scientific and Technology Department (2006YX12)the Yunnan Introduction and Foster Talent Program (2005PY01-14)
文摘The phylogenetic relationship for classification traits and eight mineral elements in brown rice （Oryza sativa L.） from Yunnan Province in China was carried out using microwave assisted digestion followed by inductively coupled plasma atomic emission spectroscopy, and the analytical procedures were carefully controlled and validated. In general, the results show that the mean levels of K, Ca, Mg, Fe and Cu in brown rice for 789 accessions of rice landraces was distinctly lower than that of improved cultivars. They further demonstrate that Ca plays an important role in the differentiation of subspecies indica-japonica, especially to enhance adaptation of cold stress, and that five mineral elements in brown rice enhance the eurytopicity from landrace to improved cultivar. Hierarchical cluster analysis, using average linkage from SPSS software based on eight mineral elements in brown rice, showed that Yunnan rice could be grouped into rice landrace and improved cultivar, with the rice landrace being further clustered into five subgroups, and that, interestingly, purple rice does not cluster with either of the groups. Our present data confirm that indica is the closest relative of late rice and white rice, and that they constitute rice landraces together, whereas japonica is the closest relatives of non-nuda, early-mid and glutinous rice. It is further shown that japonica, non-nuda, early-mid, glutinous, white and red rice might be more primitive than indica, nuda, late, non-glutinous and purple rice, respectively.
