[Objective] The aim was to develop a rapid, simple method for determination of chromium and zinc in soil samples by flame atomic absorption spectrometry.[Method] The method for determination of Cr and Zn in soil by co...[Objective] The aim was to develop a rapid, simple method for determination of chromium and zinc in soil samples by flame atomic absorption spectrometry.[Method] The method for determination of Cr and Zn in soil by combined flame atomic absorption spectrometry and microwave digestion was used. [Result] The concentration curve was linear within the range of 0-0.8 mg/L for Cr and 0-0.8 mg/L for Zn, the detection limits of Cr and Zn was 0.0025 mg/L and 0.002 3 mg/L, respectively. Recoveries of 102.4%-103.2% for Cr and 97.7%-98.3% for Zn were obtained for there soil samples. [Conclusion] The proposed method has the advantages of simple operation, high sensitivity, and high efficiency; it was successfully used for determination of Cr and Zn in soil samples.展开更多
[Objective] The aim was to develop a rapid,simple method for determination of cadmium and lead in sugarcane samples by graphite furnace atomic absorption spectrometry.[Method] The method for determination of Cd and Pb...[Objective] The aim was to develop a rapid,simple method for determination of cadmium and lead in sugarcane samples by graphite furnace atomic absorption spectrometry.[Method] The method for determination of Cd and Pb in sugarcane by combined graphite furnace atomic absorption spectrometry and microwave digestion was used.[Result] The concentration curve was linear within the range of 0-0.80 μg/L the detection limits of Cd and Pb was 0.015 and 0.030 μg/L,respectively.The precision for elevenfold determination of Cd and of Pb at the 0.40 μg/L level were 1.8% and 2.3%(RSD),respectively.Recoveries of 96.7%-98.2% for Cd and 104.6%-106.7% for Pb were obtained for two sugarcane samples and one certified reference material.[Conclusion] The proposed method has the advantages of simple operation,high sensitivity,and high efficiency;it was successfully used for determination of Cd and Pb in sugarcane samples.展开更多
The characteristics of ALA absorption spectra under different conditions are studied with spectrometers. The results indicate that the wavelength of ALA,corresponding to the strongest absorption peak, is 282 nm under ...The characteristics of ALA absorption spectra under different conditions are studied with spectrometers. The results indicate that the wavelength of ALA,corresponding to the strongest absorption peak, is 282 nm under different conditions. The content of PplX synthesized is in direct proportion to the density of Jurkat cells. The most suitable culture time is 8 hours in order to synthesize more PplX. FCS has a block effect on the synthesis of PpIX.展开更多
In quantum calculations a transformed Hamiltonian is often used to avoid singularities in a certain basis set or to reduce computation time. We demonstrate for the Fourier basis set that the Hamiltonian can not be arb...In quantum calculations a transformed Hamiltonian is often used to avoid singularities in a certain basis set or to reduce computation time. We demonstrate for the Fourier basis set that the Hamiltonian can not be arbitrarily transformed. Otherwise, the Hamiltonian matrix becomes non-hermitian, which may lead to numerical problems. Methods for cor- rectly constructing the Hamiltonian operators are discussed. Specific examples involving the Fourier basis functions for a triatomic molecular Hamiltonian (J=0) in bond-bond angle and Radau coordinates are presented. For illustration, absorption spectra are calculated for the OC10 molecule using the time-dependent wavepacket method. Numerical results indicate that the non-hermiticity of the Hamiltonian matrix may also result from integration errors. The conclusion drawn here is generally useful for quantum calculation using basis expansion method using quadrature scheme.展开更多
Because of the former gas chemistry examination method defects, tunable diode laser absorption spectrum technology (TDLAS) was used. It used an isolated absorption spectrum of the gas molecule to measure the gas abs...Because of the former gas chemistry examination method defects, tunable diode laser absorption spectrum technology (TDLAS) was used. It used an isolated absorption spectrum of the gas molecule to measure the gas absorption spectrum in order to distinguish the gas conveniently. The second harmonic (20 was measured in this system. Due to the fact which the harmonious signal is proportional to the concentration of the absorption gas, the gas concentration may be obtained through examining harmonious signal. The theoretical analysis and the experimental result indicate that under the same level of pressure, survey with the signal-to-noise ratio(SNR) of 2fsignal increases the accuracy by one order of magnitude and may reach 10 ^-3 and the sensitivity may reach the 10^-6 level compared to that of direct absorption. 5% methane density and a 30 cm absorption cell were used in the experiment. It has several advantages including high sensitivity, best resolution, and faster response and so on. The gas concentration monitoring of coal mine may be accomplished.展开更多
Some famous local spices were selected to determine their potentials in terms of their aroma and utilization. They included Tea Bush (Ocimum basilicum), Guinea Black Pepper (Piper guineense), African Pepper (Xylo...Some famous local spices were selected to determine their potentials in terms of their aroma and utilization. They included Tea Bush (Ocimum basilicum), Guinea Black Pepper (Piper guineense), African Pepper (Xylopia aethiopica), Alden Tree (Tetrapleura tetraptera) and the African Meg Nut or Onion Tree (Blighia unijugata). Essential oils were extracted from the samples and used for aroma absorption test in a uv-visible spectrometer V2.03. The intensity of aroma was indicated at some peak values of absorption at particular wavelengths. The compounds responsible for the aroma at this peak values were identified by matching their wavelengths with those of known compounds at similar wavelengths of absorption. Thus, a compound such as Quinoline that has hot strong aroma and little bleaching effect was proved to be present in Guinea black pepper ;at the wavelength of 313.0 nm. Benzene with hot strong aroma and flammable effect was also indicated in this spice at the wavelength of 253.0 rim. Proximate analysis carried out showed that these spices have high nutritive values. Some of them such as Guinea black pepper, African Nutmeg and Ethiopian (African) pepper had high ether extract of 20.01, 25.97 and 31.25 respectively, and could be regarded as oil seeds, they contain much of essential oils.展开更多
Complex absorbing potential is usually required in a time-dependent wave packet method to accomplish the calculation in a truncated region.Usually it works effectively but becomes inefficient when the wave function in...Complex absorbing potential is usually required in a time-dependent wave packet method to accomplish the calculation in a truncated region.Usually it works effectively but becomes inefficient when the wave function involves translational energy of broad range,particularly involving ultra-low energy.In this work,a new transparent boundary condition(TBC)is proposed for the time-dependent wave packet method.It in principle is of spectral accuracy when typical discrete variable representations are applied.The prominent merit of the new TBC is that its accuracy is insensitive to the translational energy distribution of the wave function,in contrast with the complex absorbing potential.Application of the new TBC is given to one-dimensional particle wave packet scatterings from a barrier with a potential well,which supports resonances states.展开更多
An all optical fiber gas sensor is presented to detect the concentration of NH3 and CO. Based on the spectral absorption, The wideband light source is used to reflect two narrowband spectra by fiber grating of differe...An all optical fiber gas sensor is presented to detect the concentration of NH3 and CO. Based on the spectral absorption, The wideband light source is used to reflect two narrowband spectra by fiber grating of different duty. and piezoelectric ceramics to obtain narrowband output light. The high sensitivity detection can be measured from the second harmonic signal. The two narrowband spectra are corresponding to the absorption spectra of NH3 and CO. Concentration detection are realized by the detection of variety of light intensity. Sensitivity is proved and cost is reduced.展开更多
An air-silica microstructure optical fiber based on the anti-resonant reflecting optical waveguide (ARROW) principle was used to develop a spectral absorption gas sensor. The ARROW fiber has an air core and an air c...An air-silica microstructure optical fiber based on the anti-resonant reflecting optical waveguide (ARROW) principle was used to develop a spectral absorption gas sensor. The ARROW fiber has an air core and an air cladding layer. An ARROW fiber with a length of 725mm was used to construct a sensing system to detect acetylene gas. The gas was injected into the fiber from one end of the fiber. The transmission spectra were collected using an optical spectrum analyzer. The results indicate that the system can detect the gas of different concentrations and has the good system linearity. The response time of the system is about 200 s.展开更多
Scanning the absorption spectral line of water vapor through wavelength around 1368.597nm is successfully used to measure the value of micro-moisture content. The synchronous superposition average of original signal a...Scanning the absorption spectral line of water vapor through wavelength around 1368.597nm is successfully used to measure the value of micro-moisture content. The synchronous superposition average of original signal algorithm based on labview is innovated and applied to detecting weak spectrum absorption signal instead of low pass filter. Two data processing methods are used to get the concentration of water vapor in ppm: one is a general formula method which has newly deduced a general formula to calculate the concentration of gas with temperature and beam intensity ratio when the pressure is equal to or greater than 1 atm; the other is engineering calibration method which is proved to have high resolution and accuracy with the fitted curve of beam intensity ratio and concentration in ppm when the temperature changes form 258K to 305K and the pressure ranges from 1 atm to 5 atm.展开更多
基金Supported by Key Fund of Guangxi Academy of Agricultural Sciences(2014JZ01 and2013YZ07)~~
文摘[Objective] The aim was to develop a rapid, simple method for determination of chromium and zinc in soil samples by flame atomic absorption spectrometry.[Method] The method for determination of Cr and Zn in soil by combined flame atomic absorption spectrometry and microwave digestion was used. [Result] The concentration curve was linear within the range of 0-0.8 mg/L for Cr and 0-0.8 mg/L for Zn, the detection limits of Cr and Zn was 0.0025 mg/L and 0.002 3 mg/L, respectively. Recoveries of 102.4%-103.2% for Cr and 97.7%-98.3% for Zn were obtained for there soil samples. [Conclusion] The proposed method has the advantages of simple operation, high sensitivity, and high efficiency; it was successfully used for determination of Cr and Zn in soil samples.
基金Supported by Fund of Guangxi Sugarcane Research Institute(G2008011)~~
文摘[Objective] The aim was to develop a rapid,simple method for determination of cadmium and lead in sugarcane samples by graphite furnace atomic absorption spectrometry.[Method] The method for determination of Cd and Pb in sugarcane by combined graphite furnace atomic absorption spectrometry and microwave digestion was used.[Result] The concentration curve was linear within the range of 0-0.80 μg/L the detection limits of Cd and Pb was 0.015 and 0.030 μg/L,respectively.The precision for elevenfold determination of Cd and of Pb at the 0.40 μg/L level were 1.8% and 2.3%(RSD),respectively.Recoveries of 96.7%-98.2% for Cd and 104.6%-106.7% for Pb were obtained for two sugarcane samples and one certified reference material.[Conclusion] The proposed method has the advantages of simple operation,high sensitivity,and high efficiency;it was successfully used for determination of Cd and Pb in sugarcane samples.
基金Supported by the National Science Foundation of China(60378018 ,60578026) ,Natural Science itemof Department of Education ofGuangdong Province(Z03018 ,04J003)
文摘The characteristics of ALA absorption spectra under different conditions are studied with spectrometers. The results indicate that the wavelength of ALA,corresponding to the strongest absorption peak, is 282 nm under different conditions. The content of PplX synthesized is in direct proportion to the density of Jurkat cells. The most suitable culture time is 8 hours in order to synthesize more PplX. FCS has a block effect on the synthesis of PpIX.
基金This work was supported by the National Basic Research Program of China (No.2013CB922200), the National Natural Science Foundation of China (No.21222308, No.21103187, and No.21133006), the Chinese Academy of Sciences, and the Key Research Program of the Chinese Academy of Sciences.
文摘In quantum calculations a transformed Hamiltonian is often used to avoid singularities in a certain basis set or to reduce computation time. We demonstrate for the Fourier basis set that the Hamiltonian can not be arbitrarily transformed. Otherwise, the Hamiltonian matrix becomes non-hermitian, which may lead to numerical problems. Methods for cor- rectly constructing the Hamiltonian operators are discussed. Specific examples involving the Fourier basis functions for a triatomic molecular Hamiltonian (J=0) in bond-bond angle and Radau coordinates are presented. For illustration, absorption spectra are calculated for the OC10 molecule using the time-dependent wavepacket method. Numerical results indicate that the non-hermiticity of the Hamiltonian matrix may also result from integration errors. The conclusion drawn here is generally useful for quantum calculation using basis expansion method using quadrature scheme.
基金Supported by National Natural Science Foundation of China (50574005) Natural Science Foundation of Education Department of Anhui, China (2005KJ081)
文摘Because of the former gas chemistry examination method defects, tunable diode laser absorption spectrum technology (TDLAS) was used. It used an isolated absorption spectrum of the gas molecule to measure the gas absorption spectrum in order to distinguish the gas conveniently. The second harmonic (20 was measured in this system. Due to the fact which the harmonious signal is proportional to the concentration of the absorption gas, the gas concentration may be obtained through examining harmonious signal. The theoretical analysis and the experimental result indicate that under the same level of pressure, survey with the signal-to-noise ratio(SNR) of 2fsignal increases the accuracy by one order of magnitude and may reach 10 ^-3 and the sensitivity may reach the 10^-6 level compared to that of direct absorption. 5% methane density and a 30 cm absorption cell were used in the experiment. It has several advantages including high sensitivity, best resolution, and faster response and so on. The gas concentration monitoring of coal mine may be accomplished.
文摘Some famous local spices were selected to determine their potentials in terms of their aroma and utilization. They included Tea Bush (Ocimum basilicum), Guinea Black Pepper (Piper guineense), African Pepper (Xylopia aethiopica), Alden Tree (Tetrapleura tetraptera) and the African Meg Nut or Onion Tree (Blighia unijugata). Essential oils were extracted from the samples and used for aroma absorption test in a uv-visible spectrometer V2.03. The intensity of aroma was indicated at some peak values of absorption at particular wavelengths. The compounds responsible for the aroma at this peak values were identified by matching their wavelengths with those of known compounds at similar wavelengths of absorption. Thus, a compound such as Quinoline that has hot strong aroma and little bleaching effect was proved to be present in Guinea black pepper ;at the wavelength of 313.0 nm. Benzene with hot strong aroma and flammable effect was also indicated in this spice at the wavelength of 253.0 rim. Proximate analysis carried out showed that these spices have high nutritive values. Some of them such as Guinea black pepper, African Nutmeg and Ethiopian (African) pepper had high ether extract of 20.01, 25.97 and 31.25 respectively, and could be regarded as oil seeds, they contain much of essential oils.
基金supported by the National Natural Science Foundation of China (No.21733006,No.21825303 and No.21688102)the Strategic Priority Research Program of Chinese Academy of Sciences (No.XDB17010200).
文摘Complex absorbing potential is usually required in a time-dependent wave packet method to accomplish the calculation in a truncated region.Usually it works effectively but becomes inefficient when the wave function involves translational energy of broad range,particularly involving ultra-low energy.In this work,a new transparent boundary condition(TBC)is proposed for the time-dependent wave packet method.It in principle is of spectral accuracy when typical discrete variable representations are applied.The prominent merit of the new TBC is that its accuracy is insensitive to the translational energy distribution of the wave function,in contrast with the complex absorbing potential.Application of the new TBC is given to one-dimensional particle wave packet scatterings from a barrier with a potential well,which supports resonances states.
文摘An all optical fiber gas sensor is presented to detect the concentration of NH3 and CO. Based on the spectral absorption, The wideband light source is used to reflect two narrowband spectra by fiber grating of different duty. and piezoelectric ceramics to obtain narrowband output light. The high sensitivity detection can be measured from the second harmonic signal. The two narrowband spectra are corresponding to the absorption spectra of NH3 and CO. Concentration detection are realized by the detection of variety of light intensity. Sensitivity is proved and cost is reduced.
基金This work was supported by the Major Program of the National Natural Science Foundation of China (Grant No. 61290311).
文摘An air-silica microstructure optical fiber based on the anti-resonant reflecting optical waveguide (ARROW) principle was used to develop a spectral absorption gas sensor. The ARROW fiber has an air core and an air cladding layer. An ARROW fiber with a length of 725mm was used to construct a sensing system to detect acetylene gas. The gas was injected into the fiber from one end of the fiber. The transmission spectra were collected using an optical spectrum analyzer. The results indicate that the system can detect the gas of different concentrations and has the good system linearity. The response time of the system is about 200 s.
基金This work was supported by Natural Science Foundation of China (60977058), Science Fund for Distinguished Young Scholars of Shandong Province of China (JQ200819), Research Award Fund for Outstanding Middle-aged' and Young Scientist of Shandong Province of China (2007BS08003), Independent Innovation Foundation of Shandong University (IIFSDU2010JC002).
文摘Scanning the absorption spectral line of water vapor through wavelength around 1368.597nm is successfully used to measure the value of micro-moisture content. The synchronous superposition average of original signal algorithm based on labview is innovated and applied to detecting weak spectrum absorption signal instead of low pass filter. Two data processing methods are used to get the concentration of water vapor in ppm: one is a general formula method which has newly deduced a general formula to calculate the concentration of gas with temperature and beam intensity ratio when the pressure is equal to or greater than 1 atm; the other is engineering calibration method which is proved to have high resolution and accuracy with the fitted curve of beam intensity ratio and concentration in ppm when the temperature changes form 258K to 305K and the pressure ranges from 1 atm to 5 atm.