LED照射光催化剂用于苯、甲苯、乙苯和二甲苯分解(英文)

Studies on the use of gas phase applications of light emitting diodes(LEDs) in photocatalysis are scarce although their photocatalytic decomposition kinetics of environmental pollutants are likely different from those in aqueous solutions.The present study evaluated the use of chips of visible light LEDs to irradiate nitrogen doped titania(N-TiO2) prepared by hydrolysis to decompose gaseous benzene,toluene,ethyl benzene,m-xylene,p-xylene,and o-xylene.Photocatalysts calcined at different temperatures were characterized by various analytical instruments.The degradation efficiency of benzene was close to zero for all conditions.For the other compounds,a conventional 8 W daylight lamp/N-TiO2 unit gave a higher photocatalytic degradation efficiency as compared with that of visible-LED/N-TiO2 units.However,the ratios of degradation efficiency to electric power consumption were higher for the photocatalytic units that used two types of visible-LED lamps(blue and white LEDs).The highest degradation efficiency was observed with the use of a calcination temperature of 350 oC.The average degradation efficiencies for toluene,ethyl benzene,m-xylene,p-xylene,and o-xylene were 35%,68%,94%,and 93%,respectively.The use of blue-and white-LEDs,high light intensity,and low initial concentrations gave high photocatalytic activities for the photocatalytic units using visible-LEDs.The morphological and optical properties of the photocatalysts were correlated to explain the dependence of photocatalytic activity on calcination temperature.The results suggest that visible-LEDs are energy efficient light source for photocatalytic gas phase applications,but the activity depends on the operational conditions.     

MoWeD, a computer program to rapidly deconvolute low resolution electrospray liquid chromatography/mass spectrometry runs to determine component molecular weights

A computer program is described that can rapidly process low-resolution electrospray liquid chromatography/mass spectrometry (LC/MS) for peptides and proteins and assign molecular weights for observed components. The program first analyzes individual scans using a deconvolution algorithm similar to that previously described by Zhang and Marshall. Results for the entire run are then sorted by mass and those values found in adjacent scans are grouped together. The list of found components can also be compared to a user defined list of target molecular weight values making it easy to compare the results from different analyses. The program also has the capability to process a rolling average of scans that improves the performance when analyzing high molecular weight components. Other program features facilitate closer examination of selected spectra or regions of the chromatogram to check the MoWeD mass assignments. The utility of the program was demonstrated by the analysis of LC/MS data derived from a complex mixture of proteins derived from a bacterial whole cell lysate that had previously been analyzed manually. The MoWeD analysis was 30 times faster and provided a more comprehensive list of the components present.     

On subwavelet sets

In this note we give a characterization of subwavelet sets and show that any point has a neighborhood which is contained in a regularized wavelet set.

     

On wavelet sets

It is proved that associated with every wavelet set is a closely related “regularized” wavelet set which has very nice properties. Then it is shown that for many (and perhaps all) pairs E, F, of wavelet sets, the corresponding MSF wavelets can be connected by a continuous path in L²(ℝ) of MSF wavelets for which the Fourier transform has support contained in E ∪ F. Our technique applies, in particular, to the Shannon and Journe wavelet sets.     

发光二极管用于活性炭负载光催化剂反应器中挥发性有机化合物的降解

The applicability of ultraviolet-light emitting diodes(LEDs)as a light source for photocatalysis using granular activated charcoal (GAC)impregnated with transition metal-enhanced photocatalysts for the control of volatile organic compounds(VOCs)was investigated. Two target compounds(toluene and methyl mercaptan)were selected to evaluate the removal activities of the TiO2/GAC composites.The photocatalysts were prepared by a sol-gel method.Methyl trimethoxy silane was added as a precursor sol solution to bind...