Showing papers by "Royal Holloway, University of London published in 1975"
TL;DR: In this article, the Grand Canonical Ensemble Monte Carlo for a Lennard-Jones fluid is presented. But the ensemble is not a complete ensemble, and there is no ensemble leader.
Abstract: (1975). Grand canonical ensemble Monte Carlo for a Lennard-Jones fluid. Molecular Physics: Vol. 29, No. 1, pp. 307-311.
395 citations
TL;DR: The results of a molecular-dynamics study of a simple model of a molten salt are reported in this paper, where the structure of the liquid is dominated by charge-ordering effects and the calculated equilibrium properties are in good agreement with the predictions of the hypernetted-chain approximation.
Abstract: The results of a molecular-dynamics study of a simple model of a molten salt are reported. The interionic pair potential which is used consists of the Coulombic term an an inverse-power repulsion which is assumed to be the same for all ions. The structure of the liquid is found to be dominated by charge-ordering effects and the calculated equilibrium properties are in good agreement with the predictions of the hypernetted-chain approximation. The relation between the self-diffusion coefficient and the electrical conductivity is discussed, and the observed deviations from the Nernst-Einstein relation in real molten salts are shown to have a natural explanation in terms of short-lived cross correlations. Data on the spectra of charge and particle density fluctuations are presented. At small wave numbers there is a propagating optic-type mode which shows a strong negative dispersion, but no Brillouin peak is seen even at the lowest wave number which is accessible. The data are analyzed in terms of a single-relaxation-time model incorporating the low-order spectral moments, for which we give explicit formulas. The fit achieved is fair, but the low-frequency behavior of the charge fluctuations at small wave numbers is incorrectly reproduced, and there is evidence for the necessity of introducing a second relaxation time. Comparison is made with results previously obtained for the classical one-component plasma.
272 citations
TL;DR: In this paper, a standard memory function analysis is made of the velocity autocorrelation functions and the main features of the long-time part of the memory function, representing the collective response of the liquid are found to be the same for both species.
Abstract: Molecular-dynamics calculations are reported for binary liquid mixtures formed from neon, argon and krypton. Two groups of computations have been made: those for mixtures of argon and krypton of various compositions at a temperature and volume close to the triple point of krypton, and those for low concentrations of neon in argon at a number of state points. The equilibrium distribution functions are discussed in terms of current conformal-solution theories and deficiencies in these theories are pointed out. The coefficients of self-diffusion are shown to be very well correlated with those of mixtures of hard spheres of appropriate diameters. A standard memory-function analysis is made of the velocity autocorrelation functions and the main features of the long-time part of the memory function, representing the collective response of the liquid, are found to be the same for both species. The relation between the coefficients of mutual diffusion and self-diffusion is also briefly considered.
93 citations
TL;DR: In this article, it was shown that if all the faces of a 3-polytope are either quadrilaterals or hexagons, then it does have a Hamiltonian circuit.
Abstract: It has been conjectured that ifP is a simple 3-polytope all of whose faces have an even number of sides, thenP has a Hamiltonian circuit. In this paper it is shown that, if all the faces ofP are either quadrilaterals or hexagons, thenP does have a Hamiltonian circuit.
58 citations
43 citations
TL;DR: In this article, the average force between two ions in a Stockmayer fluid has been computed as a function of interionic distance by Monte Carlo simulation, and the ion-solvent energy has also been calculated for each ionic configuration.
36 citations
26 citations
TL;DR: In this paper, the results of Monte-Carlo computations are used to show that an interionic potential to which corresponding-state theory can be rigorously applied is insufficiently flexible to account for details of the thermodynamic properties of molten alkali-metal salts.
Abstract: Aspects of the corresponding-states correlation of certain properties of ionic liquids and liquid mixtures are examined. The results of Monte-Carlo computations are used to show that an interionic potential to which corresponding-states theory can be rigorously applied is insufficiently flexible to account for details of the thermodynamic properties of molten alkali-metal salts. The specific model studied is one frequently referred to in discussions of the application of dimensional methods in the statistical mechanics of ionic salts. Use of the same idealized potential model in the case of mixtures leads to values of the excess thermodynamic properties which are consistent with the predictions of conformal solution theory but differ qualitatively from those observed experimentally. The possibility of using results obtained by computer simulation to extend the range of validity of existing corresponding-states relations is discussed and the example of ionic diffusivity is treated as an illustration.
25 citations
TL;DR: An exo-β-glucan hydrolase, present in the digestive juice of the snail, Helix pomatia, has been purified to homogeneity by chromatography on Bio-Gel P-60, Sephadex G-200, DEAE-cellulose, and DEAE -Sephadesadex as discussed by the authors.
21 citations
TL;DR: The artificial dimers were able to activate myosin adenosine triphosphatase by 25 %, as compared with F-actin, at protein concentrations where no polymerization could be detected, and activation was even observed after polymerization had been completely blocked by reaction with diazonium.
Abstract: reaction was stopped by addition of Tris-HCI buffer (pH7.0) to a final concentration of 50m. The protein was centrifuged down and de-polymerized by resuspension in O.~~M-ATP-~.~~M-C~C~,-O.~ m~-mercaptoethan0~-2m~-Tri~-HC1 buffer, pH7.4. The artificial dimers were purified by several chromatographic runs through Sephadex G-100; their purity was checked by sodium dodecyl sulphate disc electrophoresis. The polymerization of the dimers was strongly inhibited, but could be restored by periodate splitting of the cross-link. The dimers, however, showed full binding of ATP. They also bound myosin subfragment 1, as shown by analytical ultracentrifugation, with a ratio of 1 subfragment-1 molecule per actin monomer. The dimers were able to activate myosin adenosine triphosphatase by 25 %, as compared with F-actin, at protein concentrations where no polymerization could be detected. This activation was even observed after polymerization had been completely blocked by reaction with diazonium[lHItetrazole, as previously described for G-actin (Bender et al., 1975).
21 citations
TL;DR: There is some genetical variation between different strains of the Large White butterfly, and the pupa responds to the colour of its background in a somewhat different manner from that of many other Pierid species, displaying heterochromy rather than homochromy.
Abstract: THE Large White butterfly (Pieris brassicae L.) is a toxic species1, aposematic at all stages of its life-cycle. Probably for this reason, the pupa responds to the colour of its background in a somewhat different manner from that of many other Pierid species, displaying heterochromy (background contrasting) rather than homochromy (background matching). In this respect, there is some genetical variation between different strains (M. R., unpublished).
TL;DR: In this article, the effects of relaxing two constraints on an earlier force field for benzene and fluorobenzenes have been explored and the interesting features of the earlier field are retained with the possible exception that the dependence of the CC stretching constant is less clearly dependent on fluoro substitution on the bond.
TL;DR: Finding Mammals-Their Signs and Remains, Finding Mammals -Their Signs And Remains, the authors, is a recent work about finding mammals-their signs and remains.
Abstract: Finding Mammals-Their Signs and Remains , Finding Mammals-Their Signs and Remains , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
TL;DR: The extracellular mucilage from Beijerinckia mobilis, a member of the Azotobacteriaceae, after removal of contaminating protein, was separated into a neutral polysaccharide (N-2, 10%); a neutral, dialysable fraction (n-1, 5%), consisting of glucose and oligosaccharides containing glucose, arabinose, and rhamnose; and an acidic polysacchide (85%). N-2 (mol. wt, 1900) was highly branched and comprised glucopyr
TL;DR: In this article, the effects of polarization by the permanent dipoles are included to first order and the perturbation series is summed approximately to all orders in the dipole moments by means of two Pade approximants.
Abstract: The thermodynamic perturbation theory of Stell, Rasaiah and Narang is generalized to the case of multi-component Stockmayer fluids. The effects of polarization by the permanent dipoles is included to first order and the perturbation series is summed approximately to all orders in the dipole moments by means of two Pade approximants. The two-body and triplet terms in the expansion have been evaluated by Monte Carlo integration for a specific choice of the reference Lennard-Jones mixture and the results are used to study systematically the effect of dipolar interactions on excess thermodynamic properties. The utility of a one-fluid theory based on the van der Waals model is investigated and it is shown that the approach is useful for obtaining semi-quantitative information on mixtures of weakly polar fluids. The special case of mixtures of hydrogen chloride and xenon is considered and it is shown that the potential model used is inadequate to account for the large deviations from ideality which are observed...
TL;DR: In this article, a direct method of formulating predictors of autoregressive integrated moving average processes is given which has certain advantages over the three basic forms proposed by Box & Jenkins (1970).
Abstract: SUMMARY A direct method of formulating predictors of autoregressive integrated moving average processes is given which has certain advantages over the three basic forms proposed by Box & Jenkins (1970). Some ways of making use of this representation are discussed.
TL;DR: The development of the posterior abdominal sternites and genital phallomeres in the males of two species, Ectobius lapponicus and E. panzeri, are described and the structure of the male genitalia of E.Panzeri is atypical of other members of the subfamily Ectobiinae.
Abstract: The development of the posterior abdominal sternites and genital phallomeres in the males of two species, Ectobius lapponicus and E. panzeri (Dictyoptera: Blattidae), is described. The sex of all the nymphal instars can be determined by using characters of the posterior sternites. The structure of the male genitalia of E. panzeri is atypical of other members of the subfamily Ectobiinae. The taxonomic position of E. panzeri as an annectant species between the Plectopterinae and Ectobiinae is discussed.
TL;DR: In this article, the standard enthalpies of formation of crystalline phenylphosphinic (C6H5PO2H2) acids were determined as −(133.3 ± 4.9), −(212.6 ± 2.6), and −(124.2 ± 5.8) kcalth mol−1 at 298.15 K respectively by a combustion-calorimetric method.
TL;DR: The retention and storage of carotenoids in different concentrations by different organs suggest they may perform specialized functions in these areas of the body.
Abstract: 1. 1. Some or all of the following carotenoids, α, β-carotene, lutein, zeaxanthin and flavoxanthin, were identified in the antennae, legs, heads, wings, bodies and cocoons of two silk moths (Saturnidae). 2. 2. The greatest concentrations (per individual insect) were found in the wings, bodies or cocoons. 3. 3. The retention and storage in different concentrations by different organs suggest they may perform specialized functions in these areas of the body.
TL;DR: The response of V. agaricinum ribosomes was similar to ribosome activation in several higher plant systems, and Amino acid incorporation studies utilizing the synthetic mRNA, poly (U), suggest that the transformation was preceded by an activation of pre-existing Ribosomes.
Abstract: The level of protein synthetic activity in dark-grown cultures of Verticillium agaricinum was significantly enhanced by light. As expected the enhancement of protein synthetic activity was accompanied by a transformation of cytoplasmic monoribosomes to polyribosomes. Amino acid incorporation studies utilizing the synthetic mRNA, poly (U), suggest that the transformation was preceded by an activation of pre-existing ribosomes. The change in ribosome activity related, at least in part, to an increase in the level of peptidyl-tRNA associated with the ribosomes. In this regard the response of V. agaricinum ribosomes was similar to ribosome activation in several higher plant systems. The initial response at the level of the ribosome remains to be elucidated.
TL;DR: The expulsion of aliens from England in 1378 forms one episode in the history of the alien priories, a story which began with the norman conquest and continued into the fifteenth century.
Abstract: The expulsion of aliens from England in 1378 forms one episode in the history of the alien priories, a story which began with the norman conquest and continued into the fifteenth century. The alien priories—they may be defined as the english dependencies of foreign religious houses—had been subjected to interference from the english crown since 1295, when Edward I’s seizure of them on the outbreak of the anglo-french war became the precedent, both of occasion and method, for the future. By 1378 the priories had been in crown hands during four periods of hostilities: 1295 to 1303, 1324 to 1327, 1337 to 1360, and again from 1369.