Quantitative Analysis of Methanol in Methanol Gasoline by Calibration Transfer Strategy Based on Kernel Domain Adaptive Partial Least Squares(kda-PLS)

The application of near-infrared(NIR)spectroscopy combined with multivariate calibration methods can achieve the rapid analysis of methanol gasoline.However,instrumental or environmental differences found for spectra make it impossible to continuously apply the previously developed calibration model.Therefore,the calibration transfer technique would be required to solve the time-consuming and laborious problem of reestablishing a new model.In this work,a calibration transfer method named kernel domain adaptive partial least squares(kda-PLS)was applied to the calibration transfer from the primary instrument to the secondary ones.Firstly,wavelet transform(WT)and variable importance in projection(VIP)were employed to enhance the predictive performance of the kda-PLS transfer model.Then,the results found for the calibration transfer by piecewise direct standardization(PDS)and domain adaptive partial least squares(da-PLS)were compared to verify the calibration transfer(CT)effect of kda-PLS.The results point that the kda-PLS method can transfer the PLS model developed on the primary instrument to the secondary ones,and achieve results comparable to the those of reestablishing a new PLS model on the secondary instrument,with R_(P)^(2)=0.9979(R_(P)^(2):coefficients of determination of the prediction set),RMSEP=0.0040(RMSEP:root mean square error of the prediction set),and MREP=3.03%(MREP:mean relative error of the prediction set).Therefore,kda-PLS will provide a new method for quantitative analysis of methanol content in methanol gasoline.

Calibration chain design based on integrating sphere transfer radiometer for SI-traceable on-orbit spectral radiometric calibration and its uncertainty analysis

In order to satisfy the requirement of SI-traceable on-orbit absolute radiation calibration transfer with high accuracy for satellite remote sensors,a transfer chain consisting of a fiber coupling monochromator（FBM） and an integrating sphere transfer radiometer（ISTR） was designed in this paper.Depending on the Sun,this chain based on detectors provides precise spectral radiometric calibration and measurement to spectrometers in the reflective solar band（RSB） covering 300–2500 nm with a spectral bandwidth of 0.5–6 nm.It shortens the traditional chain based on lamp source and reduces the calibration uncertainty from 5% to 0.5% by using the cryogenic radiometer in space as a radiometric benchmark and trap detectors as secondary standard.This paper also gives a detailed uncertainty budget with reasonable distribution of each impact factor,including the weak spectral signal measurement with uncertainty of 0.28%.According to the peculiar design and comprehensive uncertainty analysis,it illustrates that the spectral radiance measurement uncertainty of the ISTR system can reach to 0.48%.The result satisfies the requirements of SI-traceable on-orbit calibration and has wider significance for expanding the application of the remote sensing data with high-quality.

WRIST FORCE SENSOR'S DYNAMIC PERFORMANCE CALIBRATION BASED ON NEGATIVE STEP RESPONSE

Negative step response experimental method is used in wrist force sensor＇s dynamic performance calibration. The exciting manner of negative step response method is the same as wrist force sensor＇s load in working. This experimental method needn＇t special experiment equipments. Experiment＇s dynamic repeatability is good. So wrist force sensor＇s dynamic performance is suitable to be calibrated by negative step response method. A new correlation wavelet transfer method is studied. By wavelet transfer method, the signal is decomposed into two dimensional spaces of time-frequency. So the problem of negative step exciting energy concentrating in the low frequency band is solved. Correlation wavelet transfer doesn＇t require that wavelet primary function be orthogonal and needn＇t wavelet reconstruction. So analyzing efficiency is high. An experimental bench is designed and manufactured to load the wrist force sensor orthogonal excitation force/moment. A piezoelectric force sensor is used to setup soft trigger and calculate the value of negative step excitation. A wrist force sensor is calibrated. The pulse response function is calculated after negative step excitation and step response have been transformed to positive step excitation and step response. The pulse response function is transferred to frequency response function. The wrist force sensor＇s dynamic characteristics are identified by the frequency response function.