79,440 research outputs found
Generalized linear isotherm regularity equation of state applied to metals
A three-parameter equation of state (EOS) without physically incorrect
oscillations is proposed based on the generalized Lennard-Jones (GLJ) potential
and the approach in developing linear isotherm regularity (LIR) EOS of Parsafar
and Mason [J. Phys. Chem., 1994, 49, 3049]. The proposed (GLIR) EOS can include
the LIR EOS therein as a special case. The three-parameter GLIR, Parsafar and
Mason (PM) [Phys. Rev. B, 1994, 49, 3049], Shanker, Singh and Kushwah (SSK)
[Physica B, 1997, 229, 419], Parsafar, Spohr and Patey (PSP) [J. Phys. Chem. B,
2009, 113, 11980], and reformulated PM and SSK EOSs are applied to 30 metallic
solids within wide pressure ranges. It is shown that the PM, PMR and PSP EOSs
for most solids, and the SSK and SSKR EOSs for several solids, have physically
incorrect turning points, and pressure becomes negative at high enough
pressure. The GLIR EOS is capable not only of overcoming the problem existing
in other five EOSs where the pressure becomes negative at high pressure, but
also gives results superior to other EOSs.Comment: 9 pages, 3 figure
Modelling and control of the flame temperature distribution using probability density function shaping
This paper presents three control algorithms for the output probability density function (PDF) control of the 2D and 3D flame distribution systems. For the 2D flame distribution systems, control methods for both static and dynamic flame systems are presented, where at first the temperature distribution of the gas jet flames along the cross-section is approximated. Then the flame energy distribution (FED) is obtained as the output to be controlled by using a B-spline expansion technique. The general static output PDF control algorithm is used in the 2D static flame system, where the dynamic system consists of a static temperature model of gas jet flames and a second-order actuator. This leads to a second-order closed-loop system, where a singular state space model is used to describe the dynamics with the weights of the B-spline functions as the state variables. Finally, a predictive control algorithm is designed for such an output PDF system. For the 3D flame distribution systems, all the temperature values of the flames are firstly mapped into one temperature plane, and the shape of the temperature distribution on this plane can then be controlled by the 3D flame control method proposed in this paper. Three cases are studied for the proposed control methods and desired simulation results have been obtained
Comparison between copper and cisplatin transport mediated by human copper transporter 1 (hCTR1)
Copper transporter 1 (CTR1) is a transmembrane protein that imports copper(i) into yeast and mammalian cells. Surprisingly, the protein also mediates the uptake of platinum anticancer drugs, e.g. cisplatin and carboplatin. To study the effects of several metal-binding residues/motifs of hCTR1 on the transport of both Cu + and cisplatin, we have constructed Hela cells that stably express a series of hCTR1 variant proteins including H22-24A, NHA, C189S, hCTR1ΔC, H139R and Y156A, and compared their abilities to regulate the accumulation and cytotoxicity of these metal compounds. Our results demonstrated that the cells expressing the hCTR1 mutants of histidine-rich motifs in the N-terminus (H22-24A, NHA) resulted in a higher basal copper level in the steady state compared to those expressing wild-type protein. However, the cellular accumulation of both copper and cisplatin in these variants was found at a similar level to that of wild type when incubated with an excess of metal compounds (100 μM). The cells expressing hCTR1 variants of H139R and Y156A exhibit lower capacities towards accumulation of copper but not cisplatin. Significantly, cells with the C189S variant partially retained the ability of the wild-type hCTR1 protein to accumulate both copper and cisplatin, while for cells expressing the C-terminus truncated variant of hCTR1 (hCTR1ΔC) this ability was absolutely abolished, suggesting that this motif is crucial for the function of the transporter. This journal is © 2012 The Royal Society of Chemistry.published_or_final_versio
A Sino-German 6cm polarisation survey of the Galactic plane - VIII. Small-diameter sources
Information of small-diameter sources is extracted from the Sino-German 6cm
polarisation survey of the Galactic plane carried out with the Urumqi 25-m
telescope. We performed two-dimensional elliptical Gaussian fits to the 6cm
maps to obtain a list of sources with total-intensity and polarised flux
densities. The source list contains 3832 sources with a fitted diameter smaller
than 16 arcmin and a peak flux density exceeding 30 mJy, so about 5 times the
rms noise, of the total-intensity data. The cumulative source count indicates
completeness for flux densities exceeding about 60 mJy. We identify 125
linearly polarised sources at 6cm with a peak polarisation flux density greater
than 10 mJy, so about 3 times the rms noise, of the polarised-intensity data.
Despite lacking compact steep spectrum sources, the 6cm catalogue lists about
20 percent more sources than the Effelsberg 21cm source catalogue at the same
angular resolution and for the same area. Most of the faint 6cm sources must
have a flat spectrum and are either HII regions or extragalactic. When compared
with the Green Bank 6cm (GB6) catalogue, we obtain higher flux densities for a
number of extended sources with complex structures. Polarised 6cm sources
density are uniformly distributed in Galactic latitude. Their number density
decreases towards the inner Galaxy. More than 80 percent of the polarised
sources are most likely extragalactic. With a few exceptions, the sources have
a higher percentage polarisation at 6cm than at 21cm. Depolarisation seems to
occur mostly within the sources with a minor contribution from the Galactic
foreground emission.Comment: A&A accepted, 9 pages, 5 figures, Tables 1 and 2 are accessible from
http://zmtt.bao.ac.cn/6cm
The Tensor Current Divergence Equation in U(1) Gauge Theories is Free of Anomalies
The possible anomaly of the tensor current divergence equation in U(1) gauge
theories is calculated by means of perturbative method. It is found that the
tensor current divergence equation is free of anomalies.Comment: Revtex4, 7 pages, 2 figure
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