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Femtosecond and nanosecond lasers were compared for ablating brass alloys. All operating parameters from both lasers were equal except for the pulse duration. The ablated aerosol vapor was collected on silicon substrates for particle size measurements or sent into an inductively coupled plasma mass spectrometer. The diameters and size distribution of particulates were measured from scanning electron microscope (SEM) images of the collected ablated aerosol. SEM measurements showed that particles ablated using nanosecond pulses were single spherical entities ranging in diameter from several micrometers to several hundred nanometers. Primary particles ablated using femtosecond ablation were ∼100 nm in diameter but formed large agglomerates. ICPMS showed enhanced signal intensity and stability using femtosecond compared to nanosecond laser ablation.Laser ablation combined with inductively coupled plasma mass spectrometry (ICPMS) is a practical method for direct solid sample chemical analysis. [1][2][3][4][5] Significant improvements in this technology have led to numerous routine applications, especially in geochemistry. Efforts are still underway to study parameters such as wavelength, 6;7 gas ambient, 8 and energy fluence 9-11 for further improving accuracy and precision of analysis. The ablated aerosol particle sizes are believed to significantly influence analytical performance using ICPMS detection. 12-14 Chemical composition, entrainment, transport, and decomposition in the ICP all are related to the size of the aerosol particles. [15][16][17] For ablation, the laser wavelength and pulse duration play a dominant role in defining the size, size distribution, and chemistry of the ablated particulates. The goal of this work was to measure particles using femtosecond and nanosecond laser ablation and establish correlations with ICPMS performance.The use of femtosecond ablation to reduce thermal effects and minimize fractionation for chemical analysis has been tested, using both IR and UV pulses. [18][19][20][21][22] By using the same laser energy and spot size (same fluence), ICPMS performance with femtosecond laser ablation showed improvements in intensity, precision, and accuracy. To further investigate these improvements, the basis of this work was to examine the relationship between the particle size distribution and ICPMS response using UV femtosecond and nanosecond laser pulses. Brass alloys were ablated with fixed laser parameters of fluence, energy, spot size, and wavelength; pulse duration was the only difference. Brass alloys are commonly chosen as samples due to the thermal volatility difference of copper and zinc. [18][19][20][21][22][23][24] These alloys are ideal for studying effects of pulse duration on fractionation and signal stability using ICPMS. The ablated aerosols also were collected on silicon substrates for scanning electron microscopic (SEM) measurements of particle sizes. EXPERIMENTAL SECTIONThe experimental configuration is shown in Figure 1. Two lasers were used; a Nd:YAG laser with 6-n...

A branchlike MoO3/polypyrrole conductive nanocomposite was facilely prepared by wrapping a homogeneous polypyrrole (PPy) layer around MoO3 nanobelts via the in situ oxidative polymerization of a self-assembled pyrrole monomer. X-ray powder diffraction characterization demonstrated that the PPy polymer does not hinder the crystallization of the MoO3 nanobelts substrate. The electrochemical tests show that the specific capacitance of 129 F g(-1) for the MoO3/PPy hybrid is higher than both pristine MoO3 and pure PPy. Moreover, the hybrid electrode with good electrical conductivity displays good cyclic stability of 90% retention after 200 cycles of charge/discharge. These results indicate a promising potential application of the MoO3/PPy nanocomposite for use as an effective electrode material in supercapacitors.