Molecular theory of elastic constants of liquid crystals. III. Application to smectic phases with tilted orientational order

Using the density functional formalism we derive expression for the distortion free energy for systems with continuous broken symmetry and use it to derive expression for the elastic constants of smectic phases in which director is tilted with respect to the smectic layer normal. As in the previous papers of the series (Phys. Rev. A {\bf 45}, 974 (1992), E {\bf 49}, 501, (1994)) the expressions for the elastic constants are written in terms of order and structural parameters. The structural parameters involve the generalised spherical harmonic coefficients of the direct pair correlation function of an effective isotropic liquid. The density of this effective isotropic liquid depends on the nature and amount of ordering present in the system and is evaluated self- consistently. We estimate the value of elastic constants using reasonable guess for the order and structural- parameters.Comment: 31 pages; 1 Fig. in GIF format, To be appear in Phys. Rev.

Exchange biasing of single-domain Ni nanoparticles spontaneously grown in an antiferromagnetic MnO matrix

Exchange biased composites of ferromagnetic single-domain Ni nanoparticles embedded within large grains of MnO have been prepared by reduction of Ni$_x$Mn$_{1-x}$O$_4$ phases in flowing hydrogen. The Ni precipitates are 15-30 nm in extent, and the majority are completely encased within the MnO matrix. The manner in which the Ni nanoparticles are spontaneously formed imparts a high ferromagnetic- antiferromagnetic interface/volume ratio, which results in substantial exchange bias effects. Exchange bias fields of up to 100 Oe are observed, in cases where the starting Ni content $x$ in the precursor Ni$_x$Mn$_{1-x}$O$_4$ phase is small. For particles of approximately the same size, the exchange bias leads to significant hardening of the magnetization, with the coercive field scaling nearly linearly with the exchange bias field.Comment: 6 pages PDFLaTeX with 9 figure

ΔI=4\Delta I=4 and ΔI=8\Delta I=8 bifurcations in rotational bands of diatomic molecules

It is shown that the recently observed $\Delta I=4$ bifurcation seen in superdeformed nuclear bands is also occurring in rotational bands of diatomic molecules. In addition, signs of a $\Delta I=8$ bifurcation, of the same order of magnitude as the $\Delta I=4$ one, are observed both in superdeformed nuclear bands and rotational bands of diatomic molecules.Comment: LaTex twice, 10 pages and 5 PS figures provided upon demand by the Author

1/z-renormalization of the mean-field behavior of the dipole-coupled singlet-singlet system HoF_3

The two main characteristics of the holmium ions in HoF_3 are that their local electronic properties are dominated by two singlet states lying well below the remaining 4f-levels, and that the classical dipole-coupling is an order of magnitude larger than any other two-ion interactions between the Ho-moments. This combination makes the system particularly suitable for testing refinements of the mean-field theory. There are four Ho-ions per unit cell and the hyperfine coupled electronic and nuclear moments on the Ho-ions order in a ferrimagnetic structure at T_C=0.53 K. The corrections to the mean-field behavior of holmium triflouride, both in the paramagnetic and ferrimagnetic phase, have been calculated to first order in the high-density 1/z-expansion. The effective medium theory, which includes the effects of the single-site fluctuations, leads to a substantially improved description of the magnetic properties of HoF_3, in comparison with that based on the mean-field approximation.Comment: 26pp, plain-TeX, JJ

Occurrence of extra-ovarian ovules in sunflower plants (Helianthus annuus L.) treated with chlorflurenol

Foliar spray of aqueous chlorflurenol solution induced the development of 1-7 (rarely up to 14) extra-ovarian ovules in the disc florets of sunflower in contrast with a single intra-ovarian ovule found in the controls. The incidence was highest at 3×10-5 M concentration

Staggering effects in nuclear and molecular spectra

It is shown that the recently observed Delta J = 2 staggering effect (i.e. the relative displacement of the levels with angular momenta J, J+4, J+8, ..., relatively to the levels with angular momenta J+2, J+6, J+10, ...) seen in superdeformed nuclear bands is also occurring in certain electronically excited rotational bands of diatomic molecules (YD, CrD, CrH, CoH), in which it is attributed to interband interactions (bandcrossings). In addition, the Delta J = 1 staggering effect (i.e. the relative displacement of the levels with even angular momentum J with respect to the levels of the same band with odd J) is studied in molecular bands free from Delta J = 2 staggering (i.e. free from interband interactions/bandcrossings). Bands of YD offer evidence for the absence of any Delta J = 1 staggering effect due to the disparity of nuclear masses, while bands of sextet electronic states of CrD demonstrate that Delta J = 1 staggering is a sensitive probe of deviations from rotational behaviour, due in this particular case to the spin-rotation and spin-spin interactions.Comment: LaTeX, 16 pages plus 30 figures given in separate .ps files. To appear in the proceedings of the 4th European Workshop on Quantum Systems in Chemistry and Physics (Marly-le-Roi, France, 1999), ed. J. Maruani et al. (Kluwer, Dordrecht

QED Corrections to Neutrino Electron Scattering

We evaluate the O(alpha) QED corrections to the recoil electron energy spectrum in the process nu_l + e --> nu_l + e (+gamma), where (+gamma) indicates the possible emission of a photon and l=e, mu or tau. The soft and hard bremsstrahlung differential cross sections are computed for an arbitrary value of the photon energy threshold. We also study the O(alpha) QED corrections to the differential cross section with respect to the total combined energy of the recoil electron and a possible accompanying photon. Their difference from the corrections to the electron spectrum is investigated. We discuss the relevance and applicability of both radiative corrections, emphasizing their role in the analysis of precise solar neutrino electron scattering experiments.Comment: 14 pages + 10 figures. Minimal changes, published versio

Acyclic pyrazolo[3,4-d]pyrimidine nucleoside as potential leishmaniostatic agent

A new synthesis of 6-amino-1-hydroxyethoxymethyl-4 (5H)-oxopyrazolo[3, 4]pyrimidine (4) has been mentioned. Compound 4 exhibited inhibition of amastigotes of Leishmania donovani to the extent of 89% at 30 μg/mL, whereas iso-guanine analogue 5 had the inhibition only to the extent of 52.8% at 100 μg/mL in vitro. In hamster model the maximum inhibitory response for compound 4 against amastigotes multiplication was observed to be 94% at 50 Mug/kg single dose for 5 consecutive days

Color Image Encryption using Chaotic Algorithm and 2D Sin-Cos Henon Map for High Security

In every form of electronic communication, data security must be an absolute top priority. As the prevalence of Internet and other forms of electronic communication continues to expand, so too does the need for visual content. There are numerous options for protecting transmitted data. It's important that the transmission of hidden messages in images remain unnoticed to avoid raising any red flags. In this paper, we propose a new deep learning-based image encryption algorithm for safe image retrieval. The proposed algorithm employs a deep artificial neural network model to extract features via sample training, allowing for more secure image network transmission. The algorithm is incorporated into a deep learning-based image retrieval process with Convolution Neural Networks(CNN), improving the efficiency of retrieval while also guaranteeing the security of ciphertext images. Experiments conducted on five different datasets demonstrate that the proposed algorithm vastly improves retrieval efficiency and strengthens data security. Also hypothesised a 2D Sin-Cos-Henon (2D-SCH)-based encryption algorithm for highly secure colour images. We demonstrate that this algorithm is secure against a variety of attacks and that it can encrypt all three colour channels of an image simultaneously