A procedure for the preconcentration of copper was described in this paper using multi-walled carbon nanotubes (MWCNTs) oxidized by potassium permanganate as the adsorbent for the enrichment of trace copper in water s...A procedure for the preconcentration of copper was described in this paper using multi-walled carbon nanotubes (MWCNTs) oxidized by potassium permanganate as the adsorbent for the enrichment of trace copper in water samples. Important parameters, such as the sample pH, the concentration and volume of eluent, sample flow rate and volume, and interference of coexisting ions, were investigated. The obtained results indicated that proposed method possessed an excellent analytical performance. The linear range, the detection limit, and precison (RSD) were 1–100 ng/mL (R(2) = 0.9993), 0.32 ng/mL and 2.88%, respectively. The results showed that copper could be adsorbed quantitatively on the pretreated MWCNTs with potassium permanganate, and proposed method was very useful in the monitoring of copper in the environment.展开更多
Solid helium bubbles were directly observed in the helium ion implanted tungsten(W), by different transmission electron microscopy(TEM) techniques at room temperature. The diameters of these solid helium bubbles r...Solid helium bubbles were directly observed in the helium ion implanted tungsten(W), by different transmission electron microscopy(TEM) techniques at room temperature. The diameters of these solid helium bubbles range from1 nm to 8 nm in diameter with the mean bubble size about 3 nm. The selected area electron diffraction(SAED) and fast Fourier transform(FFT) images revealed that solid helium bubbles possess body-centered cubic(bcc) structure with a lattice constant of 0.447 nm. High-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM)images further confirmed the existence of helium bubble in tungsten. The present findings provide an atomic level view of the microstructure evolution of helium in the materials, and revealed the existence of solid helium bubbles in materials.展开更多
A new method for analysis of trace mercury in water samples was developed, based on the combination of preconcentration/separation using dithizone-modified nanometer titanium dioxide (TiO2) as a solid phase extracta...A new method for analysis of trace mercury in water samples was developed, based on the combination of preconcentration/separation using dithizone-modified nanometer titanium dioxide (TiO2) as a solid phase extractant and determination by cold vapor atomic adsorption spectrometry (CVAAS). Dithizone was dissolved with alcohol and loaded on the surface of nano-sized TiO2 powders by stirring. The static adsorption behavior of Hg^2+on the dithizone-modified nanoparficles was investigated in detail. It was found that excellent adsorption ratio for Hg^2+ could be obtained in the pH range of 7-8 with an oscillation time of 15 rain, and a 5 mL of 3.5 mol·L^-1 HCI solution could quantitatively elute Hg^2+ from nanometer TiO2 powder. Common coexisting ions caused no obvious influence on the determination of mercury. The mechanisms for the adsorption and desorption were discussed. The detection limit (30) for Hg^2+ was calculated to be 5 ng·L^-1. The proposed method was applied to the determination of Hg^2+ in a mineral water sample and a Zhujiang River water sample. By the standard addition method, the average recoveries were found to be 94.4%-108.3% with RSD (n = 5) of 2.9%-3.5%.展开更多
The refractive index is one of the important parameters describing the optical properties of solid materials. However, it is difficult to obtain a quantitative relation between the refractive index and the structure a...The refractive index is one of the important parameters describing the optical properties of solid materials. However, it is difficult to obtain a quantitative relation between the refractive index and the structure and composition of materials. A qualitative relation between the refractive index and some atomic parameters of materials was proposed and demonstrated by some oxide optical crystals. A parameter P=r~-/F=r~-/(r~+ΔxD) is defined, in which Δx is the difference of the electronegativities between cations and anions in the materials and r~+ and r~- are the radii of cations and anions respectively. On the other hand, the factor D was introduced to describe the effect of mass difference of the ions. It is demonstrated by both theoretical discussion and experimental data that refractive index is a decreasing function of parameter P. The relation may be useful for the investigation of optical materials.展开更多
A simple and sensitive solid phase extraction utilizing C18 filled cartridges incorporated with dithizone for preconcentration of lead and its subsequent determination by flame atomic absorption spectrometry (FAAS) wa...A simple and sensitive solid phase extraction utilizing C18 filled cartridges incorporated with dithizone for preconcentration of lead and its subsequent determination by flame atomic absorption spectrometry (FAAS) was developed. Several parameters such as type, concentration and volume of eluent, pH of the sample solution, flow rate of extraction and volume of the sample were evaluated. The effect of a variety of ions on preconcentration and recovery was also investigated. At pH = 7.4 and 1.0 mol?L–1 HCl eluting them, lead ions were recovered quantitatively. The limit of detection (LOD) defined as 3Sbl was determined to be 8.1 μg L–1 for 500 mL of sample solution and eluted with 5 mL of 1.0 mol?L–1 HCl under optimum conditions. The accuracy and precision (RSD %) of the method were >90% and <10%, respectively. In the end, the proposed method was applied to a number of real sugar samples and the amount of lead was determined by spiking a known concentration of lead into the solution.展开更多
A sensitive and simple solid phase extraction method for the simultaneous determination of trace and toxic metals in environmental samples has been reported. The method is based on the adsorption of Zinc, Iron and Cop...A sensitive and simple solid phase extraction method for the simultaneous determination of trace and toxic metals in environmental samples has been reported. The method is based on the adsorption of Zinc, Iron and Copper on SDS-coated alumina nanoparticles, which is also modified with 3-mercapto-D-valine. The retained analyte ions on modified solid phase were eluted using 5 mL of 4 mol·L﹣1 HNO3. The analyte determination was carried out by flame atomic absorption spectrometry. The influences of some metal ion and anions on the recoveries of understudy analyte ion were investigated. The influences of the analytical parameters including pH, ligand and SDS amount, eluting solution (type and concentrations) and sample volume on metal ions recoveries were investigated. The extraction efficiency was > 98% with relative standard deviation lower than 3% the method has been successfully applied for the extraction and determination of these ions content in some real samples. Prepared adsorbent was characterized by SEM and FT-IR measurements.展开更多
In this study we investigated the enrichment ability of oxidized multiwalled carbon nanotubes (MWCNTs) and established a new method for the determination of trace cadmium in environment with flame atomic absorption ...In this study we investigated the enrichment ability of oxidized multiwalled carbon nanotubes (MWCNTs) and established a new method for the determination of trace cadmium in environment with flame atomic absorption spectrometry. The MWCNTs were oxidized by potassium permanganate under appropriate conditions before use as preconcentration packing. Parameters influencing the recoveries of target analytes were optimized. Under optimal conditions, the target analyte exhibited a good linearity (R^2=0.9992) over the concentration range 0.5-50 ng/ml. The detection limit and precision of the proposed method were 0.15 ng/ml and 2.06%, respectively. The proposed method was applied to the determination of cadmium in real-world environmental samples and the recoveries were in the range of 91.3%-108.0%. All these experimental results indicated that this new procedure could be applied to the determination of trace cadmium in environmental waters.展开更多
We study here effects of nozzle layout on the droplet ejection of a micro atomizer, which was fabricated with the arrayed nozzles by the MEMS technology and actuated by a piezoelectric disc. A theoretical model was fi...We study here effects of nozzle layout on the droplet ejection of a micro atomizer, which was fabricated with the arrayed nozzles by the MEMS technology and actuated by a piezoelectric disc. A theoretical model was first built for this piezoelectric-liquid-structure coupling system to characterize the acoustic wave propagation in the liquid chamber, which determined the droplet formation out of nozzles. The modal analysis was carried out numerically to predict resonant frequencies and simulate the corresponding pressure wave field. By comparing the amplitude contours of pressure wave on the liquid-solid interface at nozzle inlets with the designed nozzle layout, behaviors of the device under different vibration modes can be predicted. Experimentally, an impedance analyzer was used to measure the resonant frequencies of the system. Three types of atomizers with different nozzle layouts were fabricated for measuring the effect of nozzle distribution on the ejection performance. The visualization experiment of droplet generation was carried out and volume flow rates of these devices were measured. The good agreement between the experiment and the prediction proved that only the increase of nozzles may not enhance the droplet generation and a design of nozzle distribution from a view-point of frequency is necessary for a resonant related atomizer.展开更多
The development of laser sampling for optical emission spectrometry is reviewed . Advantages and limitations of pulsed laser sampling are compared with those of continuous laser sampling . A novel method of laser samp...The development of laser sampling for optical emission spectrometry is reviewed . Advantages and limitations of pulsed laser sampling are compared with those of continuous laser sampling . A novel method of laser sampling of liquid samples for inductively coupled plasma -atomic emission spectrometry has been proposed , and its analytical performance investigated.Experimental results showed that,as a method of sample introduction , laser vaporization of liquid samples enjoyed certain advantages , e.g.,much higher sensitivity, much lower detection limit and reduced sample volume , over solution nebulization . A perspective of the application of laser sampling-inductively coupled plasma - actomic emission spectrometry for rock and mineral analysis is estimated as well.展开更多
The quantum phase transition from the Mott insulator to the superfluid phases of the bosonic atoms trapped in an optical lattice, in which the on-site interaction carl be tuned by a Feshbach resonance, is investigated...The quantum phase transition from the Mott insulator to the superfluid phases of the bosonic atoms trapped in an optical lattice, in which the on-site interaction carl be tuned by a Feshbach resonance, is investigated by a variational approach within mean-field theory. We derive an extended Bos^Hubbard model to describe this ultracold atomic system. By theoretical calculation and analysis, the phase diagram is shown clearly, and we find an exciting and novel phenomenon that is the appearance of the Mort insulator-sea (MI-sea). Meanwhile, the experimental feasibility of observing the MI-sea is discussed by analyzing the published data related to the Fashbaeh resonance at present. Finally, the potential application of the MI-sea for quantum information processing and quantum computation is also discussed in detail展开更多
It is important to know the maximum solid solubility( C max ) of various transition metals in a metal when one designs multi component alloys. There have been several semi empirical approaches to qualitatively predict...It is important to know the maximum solid solubility( C max ) of various transition metals in a metal when one designs multi component alloys. There have been several semi empirical approaches to qualitatively predict the C max , such as Darken Gurry(D G) theorem, Miedema Chelikowsky(M C) theorem, electron concentration rule and the bond parameter rule. However, they are not particularly valid for the prediction of C max . It was developed on the basis of energetics of alloys as a new method to predict C max of different transition metals in metal Ti, which can be described as a semi empirical equation using the atomic parameters, i e, electronegativity difference, atomic diameter and electron concentration. It shows that the present method can be used to explain and deduce D G theorem, M C theorem and electron concentration rule.展开更多
Maximum solid solubility (C_ max) of different transition metals in metal solvent can be described by a semi-empirical equation using function Z_f that contains electronegativity difference, atomic diameter and electr...Maximum solid solubility (C_ max) of different transition metals in metal solvent can be described by a semi-empirical equation using function Z_f that contains electronegativity difference, atomic diameter and electron concentration. The relation between C_ max and these parameters of transition metals in vanadium solvent was studied. It is shown that the relation of C_ max and function Z_f can be expressed as lnC_ max=Z_f= 7.3165- 2.7805(ΔX) 2- 71.278δ 2-0.85556n 2/3. The factor of atomic size parameter has the largest effect on the C_ max of the V binary alloy; followed by the factor of electronegativity difference; the electrons concentration has the smallest effect among the three bond parameters. Function Z_f is used for predicting the unknown C_ max of the transition metals in vanadium solvent. The results are compared with Darken-Gurry theorem, which can be deduced by the obtained function Z_f in this work.展开更多
文摘A procedure for the preconcentration of copper was described in this paper using multi-walled carbon nanotubes (MWCNTs) oxidized by potassium permanganate as the adsorbent for the enrichment of trace copper in water samples. Important parameters, such as the sample pH, the concentration and volume of eluent, sample flow rate and volume, and interference of coexisting ions, were investigated. The obtained results indicated that proposed method possessed an excellent analytical performance. The linear range, the detection limit, and precison (RSD) were 1–100 ng/mL (R(2) = 0.9993), 0.32 ng/mL and 2.88%, respectively. The results showed that copper could be adsorbed quantitatively on the pretreated MWCNTs with potassium permanganate, and proposed method was very useful in the monitoring of copper in the environment.
基金Project supported by the ITER-National Magnetic Confinement Fusion Program(Grant Nos.2010GB109000,2011GB108009,and 2014GB123000)the National Natural Science Foundation of China(Grant No.11075119)
文摘Solid helium bubbles were directly observed in the helium ion implanted tungsten(W), by different transmission electron microscopy(TEM) techniques at room temperature. The diameters of these solid helium bubbles range from1 nm to 8 nm in diameter with the mean bubble size about 3 nm. The selected area electron diffraction(SAED) and fast Fourier transform(FFT) images revealed that solid helium bubbles possess body-centered cubic(bcc) structure with a lattice constant of 0.447 nm. High-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM)images further confirmed the existence of helium bubble in tungsten. The present findings provide an atomic level view of the microstructure evolution of helium in the materials, and revealed the existence of solid helium bubbles in materials.
基金the Natural Science Foundation of the Department of Education, Guangdong Province, China (No. 02025).
文摘A new method for analysis of trace mercury in water samples was developed, based on the combination of preconcentration/separation using dithizone-modified nanometer titanium dioxide (TiO2) as a solid phase extractant and determination by cold vapor atomic adsorption spectrometry (CVAAS). Dithizone was dissolved with alcohol and loaded on the surface of nano-sized TiO2 powders by stirring. The static adsorption behavior of Hg^2+on the dithizone-modified nanoparficles was investigated in detail. It was found that excellent adsorption ratio for Hg^2+ could be obtained in the pH range of 7-8 with an oscillation time of 15 rain, and a 5 mL of 3.5 mol·L^-1 HCI solution could quantitatively elute Hg^2+ from nanometer TiO2 powder. Common coexisting ions caused no obvious influence on the determination of mercury. The mechanisms for the adsorption and desorption were discussed. The detection limit (30) for Hg^2+ was calculated to be 5 ng·L^-1. The proposed method was applied to the determination of Hg^2+ in a mineral water sample and a Zhujiang River water sample. By the standard addition method, the average recoveries were found to be 94.4%-108.3% with RSD (n = 5) of 2.9%-3.5%.
文摘The refractive index is one of the important parameters describing the optical properties of solid materials. However, it is difficult to obtain a quantitative relation between the refractive index and the structure and composition of materials. A qualitative relation between the refractive index and some atomic parameters of materials was proposed and demonstrated by some oxide optical crystals. A parameter P=r~-/F=r~-/(r~+ΔxD) is defined, in which Δx is the difference of the electronegativities between cations and anions in the materials and r~+ and r~- are the radii of cations and anions respectively. On the other hand, the factor D was introduced to describe the effect of mass difference of the ions. It is demonstrated by both theoretical discussion and experimental data that refractive index is a decreasing function of parameter P. The relation may be useful for the investigation of optical materials.
文摘A simple and sensitive solid phase extraction utilizing C18 filled cartridges incorporated with dithizone for preconcentration of lead and its subsequent determination by flame atomic absorption spectrometry (FAAS) was developed. Several parameters such as type, concentration and volume of eluent, pH of the sample solution, flow rate of extraction and volume of the sample were evaluated. The effect of a variety of ions on preconcentration and recovery was also investigated. At pH = 7.4 and 1.0 mol?L–1 HCl eluting them, lead ions were recovered quantitatively. The limit of detection (LOD) defined as 3Sbl was determined to be 8.1 μg L–1 for 500 mL of sample solution and eluted with 5 mL of 1.0 mol?L–1 HCl under optimum conditions. The accuracy and precision (RSD %) of the method were >90% and <10%, respectively. In the end, the proposed method was applied to a number of real sugar samples and the amount of lead was determined by spiking a known concentration of lead into the solution.
文摘为对我国环境保护与控制提供技术支持,进一步完善固体废物中重点参数,本文对HJ 702—2014《固体废物砷、汞、硒、铋、锑的测定微波消解/原子荧光法》中砷的测定进行6个方面的验证:线性关系、方法检出限、测定下限、精密度、准确度和实际样品加标回收率。结果表明,线性关系达到0.9998;当称取0.5 g固体废物样品验证砷(全量)时,测得0.009μg/g检出限、0.036μg/g的测定下限,当移取40 m L固体废物浸出液验证砷(浸出液)时,测得0.08μg/L的检出限、0.32μg/L的测定下限;砷(全量)、砷(浸出液)的相对标准偏差分别为0.35%~1.0%、1.2%~2.9%;实验室砷(全量)有证标准物质相对误差分别为-4.6%~0.85%,砷(浸出液)标准浓度的相对误差分别为0.25%~3.0%;固体废物砷(全量)加标回收率分别为93.7%~97.5%,固体废物砷(浸出液)加标回收率分别为96.0%~98.1%。各项指标均满足标准方法要求,证实实验室具备原子荧光光度法测定固体废物中砷的试验条件和技术能力。
文摘A sensitive and simple solid phase extraction method for the simultaneous determination of trace and toxic metals in environmental samples has been reported. The method is based on the adsorption of Zinc, Iron and Copper on SDS-coated alumina nanoparticles, which is also modified with 3-mercapto-D-valine. The retained analyte ions on modified solid phase were eluted using 5 mL of 4 mol·L﹣1 HNO3. The analyte determination was carried out by flame atomic absorption spectrometry. The influences of some metal ion and anions on the recoveries of understudy analyte ion were investigated. The influences of the analytical parameters including pH, ligand and SDS amount, eluting solution (type and concentrations) and sample volume on metal ions recoveries were investigated. The extraction efficiency was > 98% with relative standard deviation lower than 3% the method has been successfully applied for the extraction and determination of these ions content in some real samples. Prepared adsorbent was characterized by SEM and FT-IR measurements.
基金Project supported by the Hi-Tech Research and Development Program (863) of China (No.2006AA06Z424)Personal Innovation Foundation of Universities in Henan Province (No.[2005]-126)+1 种基金Youth Science Foundation of Henan Normal University (No.2004005)Natural Science Foundation of Henan Province (No.072300460010).
文摘In this study we investigated the enrichment ability of oxidized multiwalled carbon nanotubes (MWCNTs) and established a new method for the determination of trace cadmium in environment with flame atomic absorption spectrometry. The MWCNTs were oxidized by potassium permanganate under appropriate conditions before use as preconcentration packing. Parameters influencing the recoveries of target analytes were optimized. Under optimal conditions, the target analyte exhibited a good linearity (R^2=0.9992) over the concentration range 0.5-50 ng/ml. The detection limit and precision of the proposed method were 0.15 ng/ml and 2.06%, respectively. The proposed method was applied to the determination of cadmium in real-world environmental samples and the recoveries were in the range of 91.3%-108.0%. All these experimental results indicated that this new procedure could be applied to the determination of trace cadmium in environmental waters.
基金the National Natural Science Foundation of China(50405001).
文摘We study here effects of nozzle layout on the droplet ejection of a micro atomizer, which was fabricated with the arrayed nozzles by the MEMS technology and actuated by a piezoelectric disc. A theoretical model was first built for this piezoelectric-liquid-structure coupling system to characterize the acoustic wave propagation in the liquid chamber, which determined the droplet formation out of nozzles. The modal analysis was carried out numerically to predict resonant frequencies and simulate the corresponding pressure wave field. By comparing the amplitude contours of pressure wave on the liquid-solid interface at nozzle inlets with the designed nozzle layout, behaviors of the device under different vibration modes can be predicted. Experimentally, an impedance analyzer was used to measure the resonant frequencies of the system. Three types of atomizers with different nozzle layouts were fabricated for measuring the effect of nozzle distribution on the ejection performance. The visualization experiment of droplet generation was carried out and volume flow rates of these devices were measured. The good agreement between the experiment and the prediction proved that only the increase of nozzles may not enhance the droplet generation and a design of nozzle distribution from a view-point of frequency is necessary for a resonant related atomizer.
文摘The development of laser sampling for optical emission spectrometry is reviewed . Advantages and limitations of pulsed laser sampling are compared with those of continuous laser sampling . A novel method of laser sampling of liquid samples for inductively coupled plasma -atomic emission spectrometry has been proposed , and its analytical performance investigated.Experimental results showed that,as a method of sample introduction , laser vaporization of liquid samples enjoyed certain advantages , e.g.,much higher sensitivity, much lower detection limit and reduced sample volume , over solution nebulization . A perspective of the application of laser sampling-inductively coupled plasma - actomic emission spectrometry for rock and mineral analysis is estimated as well.
基金Supported by the National Basic Research Program of China under Grant No 2005CB724500, the National Natural Science Foundation of China under No 140874009, and the Open Research Found of State Key Laboratory of Precision Spectroscopy (East China Normal University).
文摘The quantum phase transition from the Mott insulator to the superfluid phases of the bosonic atoms trapped in an optical lattice, in which the on-site interaction carl be tuned by a Feshbach resonance, is investigated by a variational approach within mean-field theory. We derive an extended Bos^Hubbard model to describe this ultracold atomic system. By theoretical calculation and analysis, the phase diagram is shown clearly, and we find an exciting and novel phenomenon that is the appearance of the Mort insulator-sea (MI-sea). Meanwhile, the experimental feasibility of observing the MI-sea is discussed by analyzing the published data related to the Fashbaeh resonance at present. Finally, the potential application of the MI-sea for quantum information processing and quantum computation is also discussed in detail
文摘It is important to know the maximum solid solubility( C max ) of various transition metals in a metal when one designs multi component alloys. There have been several semi empirical approaches to qualitatively predict the C max , such as Darken Gurry(D G) theorem, Miedema Chelikowsky(M C) theorem, electron concentration rule and the bond parameter rule. However, they are not particularly valid for the prediction of C max . It was developed on the basis of energetics of alloys as a new method to predict C max of different transition metals in metal Ti, which can be described as a semi empirical equation using the atomic parameters, i e, electronegativity difference, atomic diameter and electron concentration. It shows that the present method can be used to explain and deduce D G theorem, M C theorem and electron concentration rule.
文摘Maximum solid solubility (C_ max) of different transition metals in metal solvent can be described by a semi-empirical equation using function Z_f that contains electronegativity difference, atomic diameter and electron concentration. The relation between C_ max and these parameters of transition metals in vanadium solvent was studied. It is shown that the relation of C_ max and function Z_f can be expressed as lnC_ max=Z_f= 7.3165- 2.7805(ΔX) 2- 71.278δ 2-0.85556n 2/3. The factor of atomic size parameter has the largest effect on the C_ max of the V binary alloy; followed by the factor of electronegativity difference; the electrons concentration has the smallest effect among the three bond parameters. Function Z_f is used for predicting the unknown C_ max of the transition metals in vanadium solvent. The results are compared with Darken-Gurry theorem, which can be deduced by the obtained function Z_f in this work.