Research on the DF-TSOM method for detecting subsurface defects of optical components.

In response to the growing need for detecting subsurface defects at the hundred-nanometer scale, this study introduces what we believe to be a novel dark field through-focus scanning optical microscopy (DF-TSOM) technique. Subsurface defect samples were prepared with a depth of 100 µm and diameters of 1 µm, 0.4 µm, 0.

Transgenic Cry1Ac + CpTI cotton does not compromise parasitoid-mediated biological control: An eight-year case study.

Background: The on-farm deployment of genetically modified crops may negatively affect nontarget arthropods, potentially disrupting food web structure and ecosystem functions. Aphid-parasitoid interactions are well-suited to study these potential impacts in agro-ecosystems. Over the span of 8 years, we systematically compared infestation levels of the aphid Aphis gossypii, its associated parasitoid community and overall parasitism rate between transgenic Cry1Ac + CpTI cotton and nontransgenic cotton.

[Study on measurement of trace heavy metal Ni in water by laser induced breakdown spectroscopy technique].

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 resolution and wide spectral range. A round flat solid state graphite as matrix was used for element enrichment for reducing water splashing, extending the plasma lifetime and improving the detection sensitivity, and the experimental sample was prepared by titrating a fixed volume of nickel nitrate solution of different concentrations on a fixed area of the graphite matrix. The results show that the better detection delay time is about 700 ns, the spectrum intensity raises with the concentration increase, a good linear relationship is presented at low concentration with a correlation coefficient 0.

[Study on the automatic recognition method of elemental spectra in laser induced breakdown spetroscopy].

According to the spectral line broadening mechanism of laser induced breakdown spectroscopy, the emission lines from the standard spectral database of NIST were simulated, and they were compared with the spectral data of experiment. In the process of comparison similarity measure was used to measure the similarity between the simulative spectra and the experimental spectra. The automatic recognition method of elemental spectra was studied, and the spectral data of soil between 340 and 345 nm was recognized by computing the proportional coefficients of the spectral lines.

[Study on the automatic extraction method of spectral data features in laser induced breakdown spectroscopy].

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 automatic extraction for fitting was analysed. Automatic fitting and feature parameter extraction for spectral data of LIBS based on L-M algorithm that was hybrid programming with matrixVB and VB were accomplished,and the result was compared with the origin 7.5 data analysis software which was manual and commonly used and verified its stability and reliability.

[Measurement and analysis of copper in soil using laser-induced breakdown spectroscopy].

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 evolution of the characteristic spectral line of Cu was obtained by changing the delay time of ICCD at the same concentration and the gate of ICCD with wavelength of 329. 396 nm of Cu as the characteristic spectral line, from which the best delay time 1.

[Influence of humidity on characteristic of laser-induced soil plasmas].

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.