The level of chemical oxygen demand(COD)is an important index to evaluate whether sewage meets the discharge requirements,so corresponding tests should be carried out before discharge.Fourier transform infrared spectr...The level of chemical oxygen demand(COD)is an important index to evaluate whether sewage meets the discharge requirements,so corresponding tests should be carried out before discharge.Fourier transform infrared spectroscopy(FTIR)and attenuated total reflectance(ATR)can detect COD in sewage effectively,which has advantages over conventional chemical analysis methods.And the selection of characteristic bands was one of the key links in the application of FTIR/ATR spectroscopy.In this work,based on the moving window partial least-squares(MWPLS)regression to select a characteristic wavelength,a method of equivalent wavelength selection was proposed combining with paired t-test equivalent concept.The results showed that the prediction effect of the selected wavelength was very close to that of the MWPLS method,while the number of wavelength points was much smaller.SEPAve,RP,Ave,SEPStd,and RP,Std which characterized the modeling effect were 26.3 mg L^-1,0.969,3.49 mg L^-1,and 0.006,respectively.The validation effect V-SEP and V-RP were 28.64 mg L^-1 and 0.960,respectively.The selected waveband was between 1809 cm^-1 and 1568 cm^-1.The method was of more reference value for the design of FTIR/ATR spectral instrument for COD detection.展开更多
Comparison of the ATR-FITR spectra of nature and artificial leather shows that their feature peak positions do not overlap,By analysing their spectra and their corresponding second derivative infrared spectra we can d...Comparison of the ATR-FITR spectra of nature and artificial leather shows that their feature peak positions do not overlap,By analysing their spectra and their corresponding second derivative infrared spectra we can discriminate them easily.Analysis and discrimination of leather products by ATR-FTIR is an accurate,sensitive,quick method.展开更多
The mechanism of enhancers （methanol,chloroform,azone and thiozone） was studied in vitro in mouse stratum corneum （SC）.Attenuated total reflectance Fourier-transform infrared spectroscopy （ATR-FTIR） was applied ...The mechanism of enhancers （methanol,chloroform,azone and thiozone） was studied in vitro in mouse stratum corneum （SC）.Attenuated total reflectance Fourier-transform infrared spectroscopy （ATR-FTIR） was applied to monitor the wavenumber shifts of CH2 stretching absorbance as well as the lipid content in the SC,which were used as criteria to explain the effect of the enhancers on mouse SC.The FTIR spectra record that treatment with these four enhancers would result in significant shifts toward higher wavenumber at vasCH2 and vsCH2 and the integration areas of vasCH2 and vsCH2 decrease when treatment of methanol and choloroform.It is concluded that these four enhancers could increase the gauche conformational isomer content of lipid CH2,made the lipid in the SC a more fluid state,thus the resistance of drug transdermal delivery was reduced.展开更多
基金This work was financially supported by the Natural Science Foundation of Hainan Province(417087)the Key Research and Development Program of Hainan Province(ZDYF2018007)Research Fund for Advanced Talents of Hainan University(No.kyqd1577).
文摘The level of chemical oxygen demand(COD)is an important index to evaluate whether sewage meets the discharge requirements,so corresponding tests should be carried out before discharge.Fourier transform infrared spectroscopy(FTIR)and attenuated total reflectance(ATR)can detect COD in sewage effectively,which has advantages over conventional chemical analysis methods.And the selection of characteristic bands was one of the key links in the application of FTIR/ATR spectroscopy.In this work,based on the moving window partial least-squares(MWPLS)regression to select a characteristic wavelength,a method of equivalent wavelength selection was proposed combining with paired t-test equivalent concept.The results showed that the prediction effect of the selected wavelength was very close to that of the MWPLS method,while the number of wavelength points was much smaller.SEPAve,RP,Ave,SEPStd,and RP,Std which characterized the modeling effect were 26.3 mg L^-1,0.969,3.49 mg L^-1,and 0.006,respectively.The validation effect V-SEP and V-RP were 28.64 mg L^-1 and 0.960,respectively.The selected waveband was between 1809 cm^-1 and 1568 cm^-1.The method was of more reference value for the design of FTIR/ATR spectral instrument for COD detection.
文摘Comparison of the ATR-FITR spectra of nature and artificial leather shows that their feature peak positions do not overlap,By analysing their spectra and their corresponding second derivative infrared spectra we can discriminate them easily.Analysis and discrimination of leather products by ATR-FTIR is an accurate,sensitive,quick method.
文摘The mechanism of enhancers （methanol,chloroform,azone and thiozone） was studied in vitro in mouse stratum corneum （SC）.Attenuated total reflectance Fourier-transform infrared spectroscopy （ATR-FTIR） was applied to monitor the wavenumber shifts of CH2 stretching absorbance as well as the lipid content in the SC,which were used as criteria to explain the effect of the enhancers on mouse SC.The FTIR spectra record that treatment with these four enhancers would result in significant shifts toward higher wavenumber at vasCH2 and vsCH2 and the integration areas of vasCH2 and vsCH2 decrease when treatment of methanol and choloroform.It is concluded that these four enhancers could increase the gauche conformational isomer content of lipid CH2,made the lipid in the SC a more fluid state,thus the resistance of drug transdermal delivery was reduced.
