Nan-jing Zhao

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The spectroscopy emission characteristics and the detection limit of trace heavy metal nickel in water was studied based on laser induced breakdown spectroscopy technique, with a 1,064 nm wavelength Nd : YAG laser as excitation source, and the echelle spectrometer and ICCD detector were used for spectral separation and high sensitive detection with high(More)
Mercaptopropionic acid (MPA) capped CdTe quantum dots (QDs) with particle size 3 nm have been successfully synthesized in aqueous medium by hydrothermal synthesis method. And the effects of different metal ions on MPA capped CdTe QDs fluorescence were studied using fluorescence spectrometry. The results demonstrated that at the same concentration level,(More)
Taihu Lake is one of the five biggest lakes in China. Surface water samples from 26 sampling sites of Taihu Lake were collected. Furthermore wet chemical analysis (COD(Cr) and BOD5) and measurement of three dimensional excitation-emission matrix (3DEEM) spectra in the laboratory have been conducted. Using parallel factor analysis (PARAFAC) model, three(More)
According to that the spectral line broadening of laser induced breakdown spectroscopy (LIBS) was lorentz nonlinear function model, using Levenberg-Marquardt (L-M) agorithm to optimally estimate the undetermined parameter in the function, the continuum background radiation and peak position and peak intensity were corrected, and the method of data points(More)
The present paper analyzed the characteristics of laser-induced breakdown spectroscopy (LIBS) of metal element Cu in soil using the Nd:YAG (wavelength: 1064 nm) laser as the excitation source, where the spectral signals were detected by the highly resolved and wide spectral echelle spectrograph and intensified charge coupled device (ICCD). The time(More)
The soil samples at six different humidities were prepared for studying the influence of soil humidity on laser-induced plasmas. By analyzing the characteristic spectral lines of Pb with the wavelength of 405.78 nm, it was demonstrated that the intensities of spectral line, SNR and RSD are linearly inversely proportional to the soil humidity. Under the(More)
The fluorescence spectra of dissolved organic matter (DOM) in several types of water samples in combination with laser-induced fluorescence (LIF) measurements were measured in the laboratory, and the spectral characteristics of DOM were analysed. The curve of normalized fluorescence intensity against corresponding concentration of humic acid is showed. The(More)
By means of field sampling and laboratory analysis, the content distribution characteristics of Cd, Cr, Cu, Ni, Pb and Zn in agricultural region soils of Huaihe basin in Anhui province were analyzed. Assessment of heavy metal pollutions was conducted using enrichment factor, geoaccumulation index and potential ecological risk index. The results showed that(More)
The fluorescence intensity information was collected by scanning its fluorescence spectra at different excitation wavelengths. Based on its high sensitivity and selectivity, excitation-emission fluorescence can be widely used for detection of pollutants in the environment. The characterizations of the three phenolic compounds were investigated by this(More)
The present paper primarily tests and verifies the effect of NMF in blind source separation of three-dimensional simulative fluorescence spectra, and then four different computational algorithms (multiplicative iterative; alternating least square; second order method; projected gradient algorithm) were used in three practical phenolic compounds (cresol,(More)