Filtration and cross-flow ultrafiltration techniques were used to separate culture media of Prorocentrurn donghaiense at the exponential growth, stationary and decline stages into 〈0.45 μm filtrate, 100 kDa-0.45 μm...Filtration and cross-flow ultrafiltration techniques were used to separate culture media of Prorocentrurn donghaiense at the exponential growth, stationary and decline stages into 〈0.45 μm filtrate, 100 kDa-0.45 μm, 1%100 kDa and 1-10 kDa retentate and 〈1 kDa ultrafiltrate fractions. The fluorescence properties of different molecular weights of dissolved organic matter （DOM） were measured by excitation-emission matrix spectra. Protein-like and humic-like fluorophores were observed in the DOM produced by P. donghaiense. The central positions of protein-like fluorophores showed a red shift with prolonged growth duration, shifting from tyrosine-like properties at the exponential growth stage to tryptophan-like properties at the stationary and decline stages. The excitation wavelengths of protein-like fluorophores exhibited some change in the exponential growth and stationary stages with increased molecular size, but showed little change in the decline stage. However, the emission wavelengths in the decline stage exhibited a blue shift. Very distinct C type and A type peaks in humic-like fluorophores were observed. With a prolonged culture time, the intensities of both of the peaks became strong and the excitation wavelengths of peak A showed a red shift, while the A：C ratios fell. More than 94% of fluorescent DOM was in the lower than 1 kDa molecular weight fraction.展开更多
The self-affine measure μM,D associated with an expanding matrix M ∈ Mn(Z) and a finite digit set D ? Znis uniquely determined by the self-affine identity with equal weight. The set of orthogonal exponential functio...The self-affine measure μM,D associated with an expanding matrix M ∈ Mn(Z) and a finite digit set D ? Znis uniquely determined by the self-affine identity with equal weight. The set of orthogonal exponential functions E(Λ) := {e2πiλ,x : λ∈Λ} in the Hilbert space L2(μM,D) is simply called μM,D-orthogonal exponentials. We consider in this paper the finiteness of μM,D-orthogonality. A necessary and sufficient condition is obtained for the set E(Λ) to be a finite μM,D-orthogonal exponentials. The research here is closely connected with the non-spectrality of self-affine measures.展开更多
The furnace process is very important in boiler operation,and furnace pressure works as an important parameter in furnace process.Therefore,there is a need to analyze and monitor the pressure signal in furnace.However...The furnace process is very important in boiler operation,and furnace pressure works as an important parameter in furnace process.Therefore,there is a need to analyze and monitor the pressure signal in furnace.However,little work has been conducted on the relationship with the pressure sequence and boiler’s load under different working conditions.Since pressure sequence contains complex information,it demands feature extraction methods from multi-aspect consideration.In this paper,fuzzy c-means analysis method based on weighted validity index(VFCM)has been proposed for the working condition classification based on feature extraction.To deal with the fluctuating and time-varying pressure sequence,feature extraction is taken as nonlinear analysis based on entropy theory.Three kinds of entropy values,extracted from pressure sequence in time-frequency domain,are studied as the clustering objects for work condition classification.Weighted validity index,taking the close and separation degree into consideration,is calculated on the base of Silhouette index and Krzanowski-Lai index to obtain the optimal clustering number.Each time FCM runs,the weighted validity index evaluates the clustering result and the optimal clustering number will be obtained when it reaches the maximum value.Four datasets from UCI Machine Learning Repository are presented to certify the effectiveness in VFCM.Pressure sequences got from a 300 MW boiler are then taken for case study.The result of the pressure sequence case study with an error rate of 0.5332%shows the valuable information on boiler’s load and pressure sequence in furnace.The relationship between boiler’s load and entropy values extracted from pressure sequence is proposed.Moreover,the method can be considered to be a reference method for data mining in other fluctuating and time-varying sequences.展开更多
基金the Natural Science Foundation of Education D epartm ent of Jiangsu Province(04KJD180105),and State Key La-boratory of Palaeob iology and Stratigraphy(Nan jing Institute of Geology and Palaeontology,CAS)(053111)
基金Supported by the High Technology Research and Development Program of China (863 Program) (Nos 2006AA09Z180 and 2004AA639790)the National Natural Science Foundation of China (No 40106013)the National Basic Research Program of China (973 Program) (No 2001CB409703)
文摘Filtration and cross-flow ultrafiltration techniques were used to separate culture media of Prorocentrurn donghaiense at the exponential growth, stationary and decline stages into 〈0.45 μm filtrate, 100 kDa-0.45 μm, 1%100 kDa and 1-10 kDa retentate and 〈1 kDa ultrafiltrate fractions. The fluorescence properties of different molecular weights of dissolved organic matter （DOM） were measured by excitation-emission matrix spectra. Protein-like and humic-like fluorophores were observed in the DOM produced by P. donghaiense. The central positions of protein-like fluorophores showed a red shift with prolonged growth duration, shifting from tyrosine-like properties at the exponential growth stage to tryptophan-like properties at the stationary and decline stages. The excitation wavelengths of protein-like fluorophores exhibited some change in the exponential growth and stationary stages with increased molecular size, but showed little change in the decline stage. However, the emission wavelengths in the decline stage exhibited a blue shift. Very distinct C type and A type peaks in humic-like fluorophores were observed. With a prolonged culture time, the intensities of both of the peaks became strong and the excitation wavelengths of peak A showed a red shift, while the A：C ratios fell. More than 94% of fluorescent DOM was in the lower than 1 kDa molecular weight fraction.
基金supported by National Natural Science Foundation of China(Grant No.11171201)the Fundamental Research Fund for the Central University(Grant No.GK201401004)
文摘The self-affine measure μM,D associated with an expanding matrix M ∈ Mn(Z) and a finite digit set D ? Znis uniquely determined by the self-affine identity with equal weight. The set of orthogonal exponential functions E(Λ) := {e2πiλ,x : λ∈Λ} in the Hilbert space L2(μM,D) is simply called μM,D-orthogonal exponentials. We consider in this paper the finiteness of μM,D-orthogonality. A necessary and sufficient condition is obtained for the set E(Λ) to be a finite μM,D-orthogonal exponentials. The research here is closely connected with the non-spectrality of self-affine measures.
基金supported by the National Natural Science Foundation of China(Grant No.51176030)Jiangsu Science and Technology Department(Grant No.BY2015070-17)
文摘The furnace process is very important in boiler operation,and furnace pressure works as an important parameter in furnace process.Therefore,there is a need to analyze and monitor the pressure signal in furnace.However,little work has been conducted on the relationship with the pressure sequence and boiler’s load under different working conditions.Since pressure sequence contains complex information,it demands feature extraction methods from multi-aspect consideration.In this paper,fuzzy c-means analysis method based on weighted validity index(VFCM)has been proposed for the working condition classification based on feature extraction.To deal with the fluctuating and time-varying pressure sequence,feature extraction is taken as nonlinear analysis based on entropy theory.Three kinds of entropy values,extracted from pressure sequence in time-frequency domain,are studied as the clustering objects for work condition classification.Weighted validity index,taking the close and separation degree into consideration,is calculated on the base of Silhouette index and Krzanowski-Lai index to obtain the optimal clustering number.Each time FCM runs,the weighted validity index evaluates the clustering result and the optimal clustering number will be obtained when it reaches the maximum value.Four datasets from UCI Machine Learning Repository are presented to certify the effectiveness in VFCM.Pressure sequences got from a 300 MW boiler are then taken for case study.The result of the pressure sequence case study with an error rate of 0.5332%shows the valuable information on boiler’s load and pressure sequence in furnace.The relationship between boiler’s load and entropy values extracted from pressure sequence is proposed.Moreover,the method can be considered to be a reference method for data mining in other fluctuating and time-varying sequences.
