UV-visible spectra character of larger diameter of gold nanoparticles (AuNPs)

The dependence of the optical properties of spherical gold nanoparticles (AuNPs) on particle size and wavelength were analyzed theoretically using Mie theory, where the complex refractive index of gold was corrected for the effect of a reduced mean free path of the conduction electrons in small particles. The simulation results indicated that larger diameter AuNPs have high sensitivity and the resolution compared to the small diameter AuNPs. Two different fabricated methods for synthesis larger diameter AuNPs have been proposed. One is the directly synthesis 50nm AuNPs, the other method is separated to two steps (prepared 13nm AuNPs seeds, then synthesis 50nm AuNPs). Comparing the UV-vis spectra and SEM image of the AuNPs synthesized by these two method, we find that the symmetry of the directly synthesis method is better than the other method. The experiment results show that the synthesis AuNPs are uniform. The major aim of this work is to provide a simple and fast method to synthesis larger diameter AuNPs and research the optical properties of the nanoparticles. © (2009) Trans Tech Publications

Wavelet-Based Methodology for Evolutionary Spectra Estimation of Nonstationary Typhoon Processes

Closed-form expressions are proposed to estimate the evolutionary power spectral density (EPSD) of nonstationary typhoon processes by employing the wavelet transform. Relying on the definition of the EPSD and the concept of the wavelet transform, wavelet coefficients of a nonstationary typhoon process at a certain time instant are interpreted as the Fourier transform of a new nonstationary oscillatory process, whose modulating function is equal to the modulating function of the nonstationary typhoon process multiplied by the wavelet function in time domain. Then, the EPSD of nonstationary typhoon processes is deduced in a closed form and is formulated as a weighted sum of the squared moduli of time-dependent wavelet functions. The weighted coefficients are frequency-dependent functions defined by the wavelet coefficients of the nonstationary typhoon process and the overlapping area of two shifted wavelets. Compared with the EPSD, defined by a sum of the squared moduli of the wavelets in frequency domain in literature, this paper provides an EPSD estimation method in time domain. The theoretical results are verified by uniformly modulated nonstationary typhoon processes and non-uniformly modulated nonstationary typhoon processes

Evolutionary Spectra Estimation of Field Measurement Typhoon Processes Using Wavelets

This paper presents a wavelet-based method for estimating evolutionary power spectral density (EPSD) of nonstationary stochastic oscillatory processes and its application to field measured typhoon processes. The EPSD, which is deduced in a closed form based on the definition of the EPSD and the algorithm of the continuous wavelet transform, can be formulated as a sum of squared moduli of the wavelet functions in time domain modulated by frequency-dependent coefficients that relate to the squared values of wavelet coefficients and two wavelet functions with different time shifts. A parametric study is conducted to examine the efficacy of the wavelet-based estimation method and the accuracy of different wavelets. The results indicate that all of the estimated EPSDs have acceptable accuracy in engineering application and the Morlet transform can provide desirable estimations in both time and frequency domains. Finally, the proposed method is adopted to investigate the time-frequency characteristics of the Typhoon Matsa measured in bridge site. The nonstationary energy distribution and stationary frequency component during the whole process are found. The work in this paper may promote an improved understanding of the nonstationary features of typhoon winds

6-(2-Fluoro­phen­yl)-5,6-dihydro­benzimidazolo[1,2-c]quinazoline

In the title compound, C20H14FN3, the pyrimidine ring adopts a half-chair conformation. The dihedral angle between the benzimidazole ring system and the fluoro­phenyl ring is 84.18 (10)°. In the crystal structure, mol­ecules are linked into a two-dimensional network parallel to the bc plane by N—H⋯N and C—H⋯F hydrogen bonds

Feasibility of Direct Utilization of Biomass Gasification Product Gas Fuels in Tubular Solid Oxide Fuel Cells for On-Site Electricity Generation

Biomass is one of the most abundant and cheap renewable energy sources, and gasification product gases from the pyrolysis process of biomass, such as mallee wood and wheat straw, contain typically 20-27% H2 and a small amount of CO and CH4 (8-13%). Here, preliminary results on the performance of Ni/Y2O3-ZrO2 cermet anode-supported tubular solid oxide fuel cells (SOFCs) for the electricity generation from gasification product gases are presented. Two product gases derived from mallee wood and wheat straw are used as the fuels. The tubular SOFCs deliver a maximum power density over 576 mW cm-2 at 800 °C, close to the power density based on the equivalent amount of pure H2 or CH4 fuel. The power density is affected by the flow rate of product gas, but there are no significant differences of power output among the product gas sources used. However, the cell performance decreases gradually, and the degradation in the electricity generation performance of the tubular SOFC is most likely due to the presence of impurities, such as sulfur- and chlorine-containing compounds in the biomass feedstock. The results demonstrate the feasibility of the gasification product gas-fueled SOFCs for the on-site electricity generation, and the deterioration effect of impurities could be mitigated by cleaning the product gases or developing the contaminant-tolerant electrodes

A Facile Nanodelivery Platform Based on Functionalized Hyperbranched Poly(ether-ester) for Individualized Antitumor Drugs: Pingyangmycin as a Model

Nanodelivery of antitumor drugs is a new treatment mode for cancer. The aim of this investigation was to construct and evaluate a facile nanodelivery platform for individualized antitumor drugs based on functionalized hyperbranched poly(ether-ester)s. Poly(ether-ester)s, as a kind of hyperbranched polymers, have received extensive attention. Three terminal-functionalized (OH–, NH2– and COOH–) hyperbranched poly(ether-ester)s were prepared and characterized by dynamic light scattering and attenuated total reflectance Fourier transform infrared spectroscopy. The relationship between chemical terminal variation and physical surface charges was investigated. Biocompatibility of these polymers was confirmed by methyl tetrazolium assays and scanning electron microscopy. As a model drug, pingyangmycin has antitumor and antiangiogenic effects. In the paper, pingyangmycin was mixed with carboxyl-modified hyperbranched poly(ether-ester) through ionic binding. Polymer-mixed pingyangmycin exhibited significant inhibition of HN-6 head and neck cancer human cells in vitro. These studies demonstrate that functionalized hyperbranched (ether-ester)s can be exploited as a facile nanodelivery platform for antitumor therapy

Effects of Combined Anisodamine and Neostigmine Treatment on the Inflammatory Response and Liver Regeneration of Obstructive Jaundice Rats after Hepatectomy

Background. Cholestasis is associated with high rates of morbidity and mortality in patients undergoing major liver resection. This study aimed to evaluate the effects of a combined anisodamine and neostigmine (Ani+Neo) treatment on the inflammatory response and liver regeneration in rats with obstructive jaundice (OJ) after partial hepatectomy. Materials and Methods. OJ was induced in the rats by bile duct ligation. After 7 days biliary drainage and partial hepatectomy were performed. These rats were assigned to a saline group or an Ani+Neo treatment group. The expressions of inflammatory mediators, liver regeneration, and liver damage were assessed at 48 h after hepatectomy. Results. The mRNA levels of TNF-, IL-1 , IL-6, MCP-1, and MIP-1 , in the remnant livers, and the serum levels of TNF-and IL-1 were substantially reduced in the Ani+Neo group compared with saline group ( < 0.05). The Ani+Neo treatment obviously promoted liver regeneration as indicated by the liver weights and Ki-67 labeling index ( < 0.05). The serum albumin and -GT levels and liver neutrophil infiltration also significantly improved in the Ani+Neo group ( < 0.05) compared with the saline group. Conclusions. These results demonstrate that the combined anisodamine and neostigmine treatment is able to improve the liver regeneration in rats with OJ by substantially alleviating the inflammatory response