Thermodynamical versus log-Poisson distribution in turbulence

The thermodynamical model of intermittency in fully developed turbulence due to Castaing (B. Castaing, J. Phys. II France 6 (1996) 105) is investigated and compared with the log-Poisson model (Z-S, She, E. Leveque, Phys. Rev. Lett. 72 (1994) 336). It is shown that the thermodynamical model obeys general scaling laws and corresponds to the degenerate class of scale-invariant statistics. We also find that its structure function shapes have physical behaviors similar to the log-Poisson's one. The only difference between them lies in the convergence of the log-Poisson's structure functions and divergence of the thermodynamical one. As far as the comparison with experiments on intermittency is concerned, they are indifferent.

Reconstructing The Vertical Distribution Of The Aeolian Saltation Mass Flux Based On The Probability Distribution Of Lift-Off Velocity

The probability distribution of lift-off velocity of the saltating grains is a bridge to linking microscopic and macroscopic research of aeolian sand transport. The lift-off parameters of saltating grains (i.e., the horizontal and vertical lift-off velocities, resultant lift-off velocity, and lift-off angle) in a wind tunnel are measured by using a Phase Doppler Particle Analyzer (PDPA). The experimental results show that the probability distribution of horizontal lift-off velocity of saltating particles on a bed surface is a normal function, and that of vertical lift-off velocity is an exponential function. The probability distribution of resultant lift-off velocity of saltating grains can be expressed as a log-normal function, and that of lift-off angle complies with an exponential function. A numerical model for the vertical distribution of aeolian mass flux based on the probability distribution of lift-off velocity is established. The simulation gives a sand mass flux distribution which is consistent with the field data of Namikas (Namikas, S.L., 2003. Field measurement and numerical modelling of acolian mass flux distributions on a sandy beach, Sedimentology 50, 303-326). Therefore, these findings are helpful to further understand the probability characteristics of lift-off grains in aeolian sand transport. (c) 2007 Elsevier B.V. All rights reserved.

Effects on the proton production from explosions of hydrogen clusters subjected to intense femtosecond laser fields

The dependence of the maximum and average energies of protons, which were produced in the interaction of an intense laser pulse (similar to 1 x 10(16) W cm(-2), 65 fs) with hydrogen clusters in a gas jet backed up to 80 bar at liquid nitrogen temperature (similar to 80 K), on the backing pressure has been studied. The general trend of the proton energy dependence on the square of the average cluster radius, which is determined by a calibrated Rayleigh scattering measurement, is similar to that described by theory under the single size approximation. Calculations are made to fit the experimental results under a simplified model by taking into account both a log-normal cluster size distribution and the laser intensity attenuation in the interaction volume. A very good agreement between the experimental proton energy spectra and the calculations is obtained in the high- energy part of the proton energy distributions, but a discrepancy of the fits is revealed in the low-energy part at higher backing pressures which are associated with denser flows. A possible mechanism which would be responsible for this discrepancy is discussed. Finally, from the fits, a variation of the cluster size distributions was revealed to be dependent on the gas backing pressure as well as on the evolving time of the gas flow of clusters.

Impact of polarized illumination on high NA imaging in ArF immersion lithography at 45 nm node

Immersion lithography has been considered as the mainstream technology to extend the feasibility of optical lithography to further technology nodes. Using proper polarized illumination in an immersion lithographic tool is a powerful means to enhance the image quality and process capability for high numerical aperture (NA) imaging. In this paper, the impact of polarized illumination on high NA imaging in ArF immersion lithography for 45 nm dense lines and semi-dense lines is studied by PROLITH simulation. The normalized image log slope (NILS) and exposure defocus (ED) window are simulated under various polarized illumination modes, and the impact of polarized illumination on image quality and process latitude is analyzed. (C) 2007 Elsevier GmbH. All rights reserved.

Quantitative structure-property relationships (QSPRs) on direct photolysis of PCDDs

By the use of partial least squares (PLS) method and 27 quantum chemical descriptors computed by PM3 Hamiltonian, a statistically significant QSPR were obtained for direct photolysis quantum yields (Y) of selected Polychlorinated dibenzo-p-dioxins (PCDDs). The QSPR can be used for prediction. The direct photolysis quantum yields of the PCDDs are dependent on the number of chlorine atoms bonded with the parent structures, the character of the carbon-oxygen bonds, and molecular polarity. Increasing bulkness and polarity of PCDDs lead to decrease of log Y values. Increasing the frontier molecular orbital energies (E-lumo and E-homo) and heat of formation (HOF) values leads to increase of log Y values. (C) 2001 Elsevier Science Ltd. All rights reserved.

Measurements of bremsstrahlung spectra on SECRAL

The axial emitted bremsstrahlung spectra were measured on SECRAL (Superconducting ECR ion source with Advanced design in Lanzhou) using an HPGe detector. The spectral temperature T-spe was obtained from the linear fit of the spectra in the semi-log present. The evolution of T-spe with microwave power and magnetic field configuration is investigated in this paper.

Investigation on the influence of methanol on adsorption and leaching of pesticides with soil column liquid chromatography

The effect of methanol of low concentration on adsorption and leaching of atrazine and tebuconazole was studied in this paper. The adsorption coefficients and the retardation factors (R-m) of pesticides on EUROSOIL 3# log-linearly decreased as volumetric fraction of methanol (f(c)) was increased in the binary solvent mixtures of methanol and water. These data are consistent with solvophobic theory formerly outlined for describing the adsorption and transport of hydrophobic organic chemicals from mixed solvents. Nevertheless, the adsorption of these pesticides in soil-water system slightly increased when the soil was pre-washed with methanol in comparison with that pre-washed with water (pure water system). Furthermore, their adsorption coefficients were still higher in binary solvent systems with methanol of very low concentrations, i.e. f(c) < 0.03 for atrazine and f(c) < 0.01 for tebuconazole, than those in pure water system. The adsorption coefficients (logK(w)) of atrazine and tebuconazole predicted by solvophobic theory were 0.5792 and 1.6525, respectively, and their experimental logK(w) were 0.3701 and 1.6275 in pure water system. Obviously, the predicted log K-w of the two pesticides was higher than the experimental log K-w in pure water system. The predicted K-w and the retardation factor (R-w) in pure water system by solvophobic theory are thus possibly inaccurate. (C) 2004 Elsevier Ltd. All rights reserved.

Electrochemiluminescent detection based on solid-phase extraction at tris(2,2 '-bipyridyl)ruthenium(II)-modified ceramic carbon electrode

A sensitive electrochemiluminescent detection scheme by solid-phase extraction at Ru(bpy)(3)(2+)-modified ceramic carbon electrodes (CCEs) was developed. The as-prepared Ru(bpy)(3)(2+)-modified CCEs show much better long-term stability than other Nafion-based Ru(bpy)(3)(2+)-modified electrodes and enjoy the inherent advantages of CCEs. The log-log calibration plot for dioxopromethazine is linear from 1.0 x 10(-9) to 1.0 x 10(-4) mol L-1 using the new detection scheme. The detection limit is 6.6 x 10(-10) mol L-1 at a signal-to-noise ratio of 3. The new scheme improves the sensitivity by similar to 3 orders of magnitude, which is the most sensitive Ru(bpy)(3)(2+) ECL method. The scheme allows the detection of dioxopromethazine in a urine sample within 3 min. Since Ru(bpy)(3)(2+) ECL is a powerful technique for determination of numerous amine-containing substances, the new detection scheme holds great promise in measurement of free concentrations, investigation of protein-drug interactions and DNA-drug interactions, pharmaceutical analysis, and so on.

Kinetics of atomic force microscope-based scanned probe oxidation on an octadecylated silicon(111) surface

Atomic force microscope (AFM)-based scanned probe oxidation (SPO) nanolithography has been carried out on an octadecyl-terminated Si(111) surface to create dot-array patterns under ambient conditions in contact mode. The kinetics investigations indicate that this SPO process involves three stages. Within the steadily growing stage, the height of oxide dots increases logarithmically with pulse duration and linearly with pulse voltage. The lateral size of oxide dots tends to vary in a similar way. Our experiments show that a direct-log kinetic model is more applicable than a power-of-time law model for the SPO process on an alkylated silicon in demonstrating the dependence of oxide thickness on voltage exposure time within a relatively wide range. In contrast with the SPO on the octodecysilated SiO2/silicon surface, this process can be realized by a lower voltage with a shorter exposure time, which will be of great benefit to the fabrication of integrated nanometer-sized electronic devices on silicon-based substrates. This study demonstrates that the alkylated silicon is a new promising substrate material for silicon-based nanolithography.

Study on QSPR of alcohols with a novel edge connectivity index F-m

A novel edge degree f(i) for heteroatom and multiple bonds in molecular graph is derived on the basis of the edge degree delta(e(r)). A novel edge connectivity index F-m is introduced. The multiple linear regression by using the edge connectivity index F-m and alcohol-type parameter delta, alcohol-distance parameter L can provide high-quality QSPR models for the normal boiling points (BPs), molar volumes (MVs), molar refraction (MRs), water solubility(log(1/S)) and octanol/water partition (logP) of alcohols with up to 17 non-hydrogen atoms. The results imply that these physical properties may be expressed as a liner combination of the edge connectivity index and alcohol-type parameter, 6, alcohol-distance parameter, L. For the models of the five properties, the correlation coefficient r and the standard errors are 0.9969,3.022; 0.9993, 1.504; 0.9992, 0.446; 0.9924,0.129 and 0.9973,0.123 for BPs, MVs, MRs, log(1/S) and logP, respectively. The cross-validation by using the leave-one-out method demonstrates the models to be highly reliable from the point of view of statistics.

Characterization and ionic conductivity of an amorphous comblike polymer - II: Based on ethylene maleic anhydride copolymer backbone with monoethyl ether of poly(ethylene glycol) of M-W=550 as side chain

Using a graft modification method, a comblike polymer host (CBPE550) was synthesized by reacting monomethyl ether of poly(ethylene glycol) (PEGMA) with ethylene-maleic anhydride copolymer (EMAC) and endcapping the residual carboxylic acid with methanol. The product was characterized by IR and elementary analysis. Result showed that the product was amorphous and semi-ester product is accord with reaction equation. There were two peaks in the plot of the ionic conductivity against Li salt concentration. The plot of log a against 1/(T - T-0) shows a dual VTF behavior when using the glass transition temperature of PEO of side chain as T beta. The comblike polymer is a white rubbery solid. It can be well-dissolved in acetone. (C) 1999 Elsevier Science Ltd. All rights reserved.

Study on a comb-like polymer electrolyte based on the backbone of ethylene-maleic anhydride copolymer

A comb-like polymer host(CBPE) as polymer electrolyte was synthesized by reacting poly(ethylene glycol) monomethyl ether (PEGME) with ethylene-maleic anhydride copolymer(EMAC) and endcapping the residual carboxylic acid with methanol. The synthetic process was followed by IR and the amorphous product characterized by IR and elemental analysis. There were two peaks in the plot of the ionic conductivity against Li salt concentration. The plot of log sigma vs. 1/(T - T-0) may exhibit dual VTF behavior when using the glass transition temperature of PEO of side chain as T-0. The comb-like polymer is a white rubbery solid which dissolves in acetone. (C) 1998 Elsevier Science B.V. All rights reserved.

The effect of substrate and solvent properties on the response of an organic phase tyrosinase electrode

The responses of a cryohydrogel tyrosinase enzyme electrode to four substrates in three pure water immiscible organic solvents were investigated. Kinetic parameters, the maximum kinetic current, I-max, the apparent Michaelis-Menten constant, K-m(app), and I-max/K-m(app), were calculated. The I-max/K-m(app) value was taken as an indicator of the catalytic efficiency of the sensor. The effect of the substrate hydrophobicity on I-max/K-m(app) and response time of the sensor were discussed. The effects of both hydrophobicity (log P) and dielectric constant (epsilon) of the organic solvent on the catalytic efficiency of the enzyme in the organic phase were studied. (C) 1997 Elsevier Science S.A.

The relation between molecular motion and ion conductivity on a new comblike polymer

A new amorphous comblike polymer(CBP) based on methylvinyl ether/maleic anhydride alternating copolymer backbone and on oligooxyethylene side chain was synthesized The dynamic mechanical properties of CBP-Li salt complexes showed that there were two glass transitions. There are two peaks in the plot of the ionic conductivity vs. Li salt concentration. The plot of Log sigma against 1/(T-To) shows an unusual dual VTF behavior when using sidechain glass transition temperature (T-beta) as To.

Low-amplitude BSRs and gas hydrate concentration on the northern margin of the South China Sea

The passive northern continental margin of the South China Sea is rich in gas hydrates, as inferred from the occurrence of bottom-simulating reflectors (BSR) and from well logging data at Ocean Drilling Program (ODP) drill sites. Nonetheless, BSRs on new 2D multichannel seismic reflection data from the area around the Dongsha Islands (the Dongsha Rise) are not ubiquitous. They are confined to complex diapiric structures and active fault zones located between the Dongsha Rise and the surrounding depressions, implying that gas hydrate occurrence is likewise limited to these areas. Most of the BSRs have low amplitude and are therefore not clearly recognizable. Acoustic impedance provides information on rock properties and has been used to estimate gas hydrate concentration. Gas hydrate-bearing sediments have acoustic impedance that is higher than that of the surrounding sediments devoid of hydrates. Based on well logging data, the relationship between acoustic impedance and porosity can be obtained by a linear regression, and the degree of gas hydrate saturation can be determined using Archie's equation. By applying these methods to multichannel seismic data and well logging data from the northern South China Sea, the gas hydrate concentration is found to be 3-25% of the pore space at ODP Site 1148 depending on sub-surface depth, and is estimated to be less than values of 5% estimated along seismic profile 0101. Our results suggest that saturation of gas hydrate in the northern South China Sea is higher than that estimated from well resistivity log data in the gas hydrate stability zone, but that free gas is scarce beneath this zone. It is probably the scarcity of free gas that is responsible for the low amplitudes of the BSRs.