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Nonuniform aperture synthesis radiometers (NASRs) are emerging in Earth remote sensing. The main disadvantage of NASRs is the complexity of the image reconstruction. In this letter, the gridding method is introduced as an efficient method to reconstruct brightness temperature images for NASRs. In the gridding method, a Voronoi diagram is applied to dividing the sampling region in the spatial frequency domain into a number of small cells, and the area of each cell is regarded as the density compensation factor. Meanwhile, a method is proposed to produce the outermost Voronoi cells for the outermost visibility samples. The errors induced by using the gridding method are analyzed. The nonuniformity factor (NF) is defined to indicate the nonuniformity of a sampling pattern. The numerical results verify that the gridding method can be applied to image reconstruction for NASRs and that the accuracy of reconstructed images is dependent on NF. The comparison between the gridding method and the nonuniform fast Fourier transform algorithm shows that the gridding method has lower computational complexity. [ABSTRACT FROM PUBLISHER]

Abstract: The volatilization behavior of chlorine in three Chinese bituminous coals during pyrolysis and CO2-gasification in a fluidized bed reactor was investigated. The modes of occurrence of chlorine in raw coals and their char samples were determined using sequential chemical extraction method. The Cl volatility increases with increasing temperature. Below 600°C the Cl volatility is different, depending on the coal type and the occurrence mode of Cl. Above 700°C, the Cl volatilities for the three coals tested are all higher than 80%. About 41% of the chlorine in Lu-an coal and 73% of that in Yanzhou coal are organic forms, and most of them are covalently-bonded organic chlorine, which shows high volatile behavior even at low pyrolysis temperatures (below 500°C), while the inorganic forms of chlorine in two coal samples are hardly volatilized even at low pyrolysis temperatures (below 400°C). The restraining efficiency of addition of CaO on chlorine volatility is greatly dependent on pyrolysis temperature. The optimal restraining efficiency can be obtained at temperature range from 450 to 650°C during pyrolysis of Lu-an coal. The volatile behavior of Cl is mainly dependent on temperature. Above 700°C high volatility of Cl is obtained in both N2 and CO2 atmospheres. [Copyright &y& Elsevier]

A gas-sensor utilizing cataluminescence (CTL) on nanosized γ-Al2O3 + Nd2O3 for measuring low concentrations of gaseous ethylene dichloride (EDC) was developed. The results showed that γ-Al2O3 nanoparticles as a catalyst offered high sensitivity and selectivity in the detection of EDC. The addition of a small quantity of Nd2O3 increased the intensity of CTL more than two-fold. Quantitative analysis was performed at a wavelength of 400 nm and at an optimal temperature of 279°C, and the optimal flow rate of carrier gas was 320 mL[sol ]min. Under the optimized conditions, the linear range of CTL intensity vs. concentration is 6-5000 ppm ( R = 0.9996; n = 7), with a detection limit of 2 ppm. The response time is <5 s. No interference or only very low levels of significant interference were observed when substances such as formaldehyde, n-hexane, methyl benzene, carbon tetrachloride, chloroform and benzene were passed through the sensor. Copyright © 2005 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: The volatilization behavior of fluorine in five Chinese coals was investigated during fluidized-bed pyrolysis and CO2-gasification at a temperature range of 500–900°C. The effect of co-existed and added calcium on fluorine volatility during pyrolysis was also determined. With increasing pyrolysis temperature, the volatility of fluorine increases. However, the volatility is greatly dependent on the fluorine chemical forms occurred in coal. Except for Datong and Zhungeer coal, more than 65% of fluorine in other three coals occurs as the steady forms. Fluorapatite is not the major carrier of fluorine in the coals studied. Fluorine volatility is retarded by coexisting calcium during coal pyrolysis, indicating that at least part of the stable forms of fluorine in coal might occur as calcium fluoride or calcium fluoride with complex compounds which are stable even at high pyrolysis temperature. The addition of CaO and limestone can suppress the release of fluorine during pyrolysis. The effect of CaO is better than that of limestone. The volatility of fluorine of coal during CO2-gasification depends on not only the occurrence mode of fluorine, but also the gasification reactivity of the coal. Compared with N2 atmosphere, CO2 is more favorable to the release of fluorine from coal. [Copyright &y& Elsevier]

We set up a tripartite entangled state representation |p, χ[sub 2], χ[sub 3]> in three-mode Fock space which is composed of the common eigenvectors of three particles' relative coordinates X[sub 1] - X[sub 2] and X[sub 1] - X[sub 3] as well as the total momentum P[sub 1] + P[sub 2] + P[sub 3]. The Schmidt decomposition of |p, χ[sub 2], χ[sub 3] > is made and its application in quantum teleporting a two-particle entangled state or a two-mode squeezed state is analyzed. [ABSTRACT FROM AUTHOR]

A gas-sensor utilizing cataluminescence (CTL) on nanosized gamma-Al2O3 + Nd2O3 for measuring low concentrations of gaseous ethylene dichloride (EDC) was developed. The results showed that gamma-Al2O3 nanoparticles as a catalyst offered high sensitivity and selectivity in the detection of EDC. The addition of a small quantity of Nd2O3 increased the intensity of CTL more than two-fold. Quantitative analysis was performed at a wavelength of 400 nm and at an optimal temperature of 279 degrees C, and the optimal flow rate of carrier gas was 320 mL/min. Under the optimized conditions, the linear range of CTL intensity vs. concentration is 6-5000 ppm (R = 0.9996; n = 7), with a detection limit of 2 ppm. The response time is <5 s. No interference or only very low levels of significant interference were observed when substances such as formaldehyde, n-hexane, methyl benzene, carbon tetrachloride, chloroform and benzene were passed through the sensor., (Copyright 2005 John Wiley & Sons, Ltd.)