First-principles investigation of CO and CO2 adsorption on pristine and Fe-doped planar carbon allotrope net-Y.

A new planar carbon allotrope named net-Y with periodic four-six-eight-membered carbon rings has been synthesized in this study. In this paper, the adsorption properties of CO and CO2 on the pristine net-Y and two Fe-doped net-Y surfaces were studied using first-principles calculations. Using adsorption energy, charge analysis, adsorption distance, deformation charge density and density of states, it can be found that the adsorption of CO and CO2 on the pristine net-Y surface appears as physisorption with weak interactions. Based on this, in order to enhance the adsorption strength of CO and CO2 on the surface of net-Y, Fe-doping is performed on net-Y. The calculation results after doping show that the doping of Fe atoms at different positions can significantly improve the adsorption strength of the two gas molecules. After CO and CO2 are adsorbed on the doped net-Y surface, the adsorption energy is greatly improved compared with the pristine adsorption energy, which makes the two gas molecules form a chemical bond with the substrate. Subsequently, the results of charge density and density of states further prove that the adsorption system shows chemisorption with strong interactions. Comparing doped and pristine adsorption, after Fe doping, the adsorption of CO and CO2 is stronger, which makes it possible to use this material effectively for the adsorption and removal of CO and CO2 gases.

[Experiment Research and Analysis of Spectral Prediction on Soil Leaking Oil Content].

The spectral analysis method was applied experimentally to extract the spectral indices, measure and analyze the spectral characteristics and their difference of the mixture which are composed in soil in Central Shaanxi Plain and the diesel and motor oil respectively, aiming to provide solutions to practical difficulties in detecting, analyzing the spectral characteristics and difference between the soil leaking with equal content diesel and motor oil and predicting the leaking content of diesel in the soil. The spectral response curves of the soil leaking with different oil respectively and the soil leaking with diesel with different content were collected. Then the spectral prediction model for the leaking content of diesel in the soil was built based on the reflectance characteristics. The coefficient of the detection (R2) was introduced to evaluate the stability of the built model，and the parameter root mean squared error (RMSE) was introduced to estimate the precision and the predictability of the model built in this work. It is demonstrated that : (1) The reflectance of soil leaking with diesel is less than that of the equal content motor oil. And there is a double absorption trough of the reflectance curve of both soil leaking with diesel and motor oil at 1 740 and 2 328 nm. The spectral absorption indices and absorption depth of the soil leaking with diesel keep less than the equal content motor oil. (2) The built spectral prediction model for the leaking content of diesel in the soil demonstrates good stability with the coefficient of determination at R2=0.854, and performs favorable predictability (Root-Mean-Square Error, RMSE=0.016), which can benefit the effective prediction and quick estimation methods of the leaking content of diesel in the soil, enrich and progress the experimental method and theoretical research work of spectral prediction on soil leaking oil content and promote the application of remote sensing in safety production and environmental protection.

[Selection of interpolation methods used to mitigate spectral misregistration of imaging spectrometers].

Spectral curvature destroys the co-registration of the spectra measured by dispersion imaging spectrometer. Using interpolation to re-sample the measured spectra at the non-offset mid-wavelengths can mitigate the spectral misregistration. It is very important to select an optimum interpolation method. The performances of six common interpolation methods are evaluated by comparing the residual errors in the corrected spectral radiance. The results indicate that, four-point cubic Lagrange interpolation and cubic spline interpolation are better than other four interpolation methods (linear Interpolation, three points quadratic polynomial interpolation, five points four-order Lagrange interpolation and cubic Hermite interpolation). For spectral offset of 10% deltalambda (deltalambda = 5 nm), the normalized errors in measured spectral radiance is PV = 0.06, that is reduced to PV < 0.022 after interpolation with cubic Lagrange interpolation or cubic spline interpolation, but for other four methods they are PV > 0.035. Furthermore, for lower spectral resolution (deltalambda > 5 nm), cubic Lagrange interpolation is a little better than cubic spline interpolation; while for higher spectral resolution (deltalambda < 5 nm), cubic spline interpolation is a little better.

[Hadamard transform spectrometer mixed pixels' unmixing method].

Hadamard transform imaging spectrometer is a multi-channel digital transform spectrometer detection technology, this paper based on digital micromirror array device (DMD) of the Hadamard transform spectrometer working principle and instrument structure, obtained by the imaging sensor mixed pixel were analyzed, theory derived the solution of pixel aliasing hybrid method, simulation results show that the method is simple and effective to improve the accuracy of mixed pixel spectrum more than 10% recovery.