Gyro's fault diagnosis plays a critical role in inertia navigation systems for higher reliability and precision. A new fault diagnosis strategy based on the statistical parameter analysis (SPA) and support vector ...Gyro's fault diagnosis plays a critical role in inertia navigation systems for higher reliability and precision. A new fault diagnosis strategy based on the statistical parameter analysis (SPA) and support vector machine (SVM) classification model was proposed for dynamically tuned gyroscopes (DTG). The SPA, a kind of time domain analysis approach, was introduced to compute a set of statistical parameters of vibration signal as the state features of DTG, with which the SVM model, a novel learning machine based on statistical learning theory (SLT), was applied and constructed to train and identify the working state of DTG. The experimental results verify that the proposed diagnostic strategy can simply and effectively extract the state features of DTG, and it outperforms the radial-basis function (RBF) neural network based diagnostic method and can more reliably and accurately diagnose the working state of DTG.展开更多
This paper describes the fabrication, characterization and properties of a novel hybrid poly（ethylene glycol） （PEG） based hydrogel via in situ polymerization. The hybrid hydrogel was fabricated by free-radical red...This paper describes the fabrication, characterization and properties of a novel hybrid poly（ethylene glycol） （PEG） based hydrogel via in situ polymerization. The hybrid hydrogel was fabricated by free-radical redox polymerization using ammonium persulfate （APS） and N, N, N/, NCtetramethylethylenediamine （TEMED） as initiators and N, NCmethylene bisacrylamide （BIS） as cross-linker at 60~C. To create a hybrid hydrogel, 0.2% （mass fraction） of MgA1 layered double hydroxide （LDH） was added to the aqueous solution by ultrasonic disper- sion. The physicochemical properties of hybrid hydrogel under vacuum freeze-drying processing were characterized by Fourier transform infrared （FTIR） spectroscopy, thermal gravimetric analysis （TGA） and scanning electron microscopy （SEM）, while swelling kinetics and gel content were calculated. Swelling degree in distilled water varied from 94%--125% with a gel mass fraction of 83%--91%. SEM images showed that the micron pore size of hydrogel could be adjusted within the range of several micrometers by changing the cross-linker mass fraction from 2% to 10% （based on glycol）. The results showed that the hybrid hydrogels exhibited excellent physicochemical behavior and might be a promising material for applications in tissue engineering and drug delivery.展开更多
文摘Gyro's fault diagnosis plays a critical role in inertia navigation systems for higher reliability and precision. A new fault diagnosis strategy based on the statistical parameter analysis (SPA) and support vector machine (SVM) classification model was proposed for dynamically tuned gyroscopes (DTG). The SPA, a kind of time domain analysis approach, was introduced to compute a set of statistical parameters of vibration signal as the state features of DTG, with which the SVM model, a novel learning machine based on statistical learning theory (SLT), was applied and constructed to train and identify the working state of DTG. The experimental results verify that the proposed diagnostic strategy can simply and effectively extract the state features of DTG, and it outperforms the radial-basis function (RBF) neural network based diagnostic method and can more reliably and accurately diagnose the working state of DTG.
基金the National Natural Science Foundation of China(No.31000427)the China Postdoctoral Science Foundation(No.20100481214)the Fundamental Research Funds for the Central Universities of China(Nos.2012QN052 and 2012TD013)
文摘This paper describes the fabrication, characterization and properties of a novel hybrid poly（ethylene glycol） （PEG） based hydrogel via in situ polymerization. The hybrid hydrogel was fabricated by free-radical redox polymerization using ammonium persulfate （APS） and N, N, N/, NCtetramethylethylenediamine （TEMED） as initiators and N, NCmethylene bisacrylamide （BIS） as cross-linker at 60~C. To create a hybrid hydrogel, 0.2% （mass fraction） of MgA1 layered double hydroxide （LDH） was added to the aqueous solution by ultrasonic disper- sion. The physicochemical properties of hybrid hydrogel under vacuum freeze-drying processing were characterized by Fourier transform infrared （FTIR） spectroscopy, thermal gravimetric analysis （TGA） and scanning electron microscopy （SEM）, while swelling kinetics and gel content were calculated. Swelling degree in distilled water varied from 94%--125% with a gel mass fraction of 83%--91%. SEM images showed that the micron pore size of hydrogel could be adjusted within the range of several micrometers by changing the cross-linker mass fraction from 2% to 10% （based on glycol）. The results showed that the hybrid hydrogels exhibited excellent physicochemical behavior and might be a promising material for applications in tissue engineering and drug delivery.
