Recoil corrections to magnetic moments of charmed baryons in themit bag model

Recoil corrections to magnetic moments of charmed baryons are studied in themit bag model. It is noticed that such corrections which improve the octet baryon magnetic moments have considerably significant contributions to charmed baryon’s moments also.     

Classification of Three-Dimensional Integrable Scalar Discrete Equations

We classify all integrable three-dimensional scalar discrete affine linear equations Q ₃ = 0 on an elementary cubic cell of the lattice . An equation Q ₃ = 0 is called integrable if it may be consistently imposed on all three-dimensional elementary faces of the lattice . Under the natural requirement of invariance of the equation under the action of the complete group of symmetries of the cube we prove that the only non-trivial (non-linearizable) integrable equation from this class is the well-known dBKP-system. SPT acknowledges partial financial support from a grant of Siberian Federal University (NM-project No 45.2007) and the RFBR grant 06-01-00814.     

Adiabatic time-dependent Hartree-Fock theory with the consistency condition

Adiabatic time-dependent Hartree-Fock (atdhf) theory, including the authors’ work in this field, has been summarised. In response to the criticism of Yamamuraet al the role of curvature in preventing the choice ofpure rpa mode as the solution near the static Hartree-Fock minimum has been discussed.     

The application ofclean to crystallographic problems

It is suggested that the radio astronomical technique of image reconstruction calledclean could be profitably used in crystallography to improve sharpened Patterson maps andE-maps. The method is here generalized to handle the symmetries which arise in crystallographic maps. Simulations on model one and two dimensional structure are presented to illustrate the power of the method.     

Exact energy eigenvalues by summation of thejwkb series

For the potentialV(x)=V ₀ tan² x, the corrections to the lowest orderjwkb (Bohr-Sommerfeld) energy quantization rule are non-zero. These higher order corrections are explicitly computed using the formalism of Dunham. The resultingjwkb series for the energy eigenvalues is summable, and yields the exact bound state spectrum.     

Semiempirical molecular orbital calculations for four-, six- and eight-atom systems

The geometry, bond order, binding energy, ionisation potential, dipole moment and net charges have been calculated for cis-N₂O₂, trans-N₂O₂, N₂O₄, BF₃, CH₃, NH₃, BH₃ and B₂H₆ systems using semiempirical molecular orbital methodsindo and the results compared with available experimental,ab initio andmindo/3 data.     

The Hamiltonian constraint in the teleparallel equivalent of general relativity

In the teleparallel equivalent of general relativity the integral form of the Hamiltonian constraint contains explicitly theadm energy in the case of asymptotically flat space-times. We show that such expression of the constraint leads to a natural and straightforward construction of a Schrödinger equation for time-dependent physical states. The quantized Hamiltonian constraint is thus written as an energy eigenvalue equation. We further analyse the constraint equations in the case of a space-time endowed with a spherically symmetric geometry. We find the general functional form of the time-dependent solutions of the quantized Hamiltonian and vector constraints.     

A programmable digital pulse generator for pulsednmr spectroscopy

The pulse programmer generates highly stable pulses and is capable of producing various scheme of pulses (i.e. a given specific number of pulses with independently variable widths and separations) employed in pulsednmr spectroscopy. The construction and working of the programmer is described with reference to the two most commonly used schemes, namely, a two-pulse sequence and the Carr-Purcell sequence.     

Off-diagonal long-range order and currents in weakly coupled superconductors

Within the framework of quasi equilibrium approximation, Josephson’s expression for current in a weakly coupled superconducting system is derived without the use of any specific microscopic model. It is based only on the existence of the off-diagonal long-range order in the two-particle reduced density matrix. Allowing for deviations from the quasi equilibrium approximation, generalised Josephson equations are obtained which include ohmic terms. The effect of relaxation and thermal fluctuations is examined in detail to emphasise the physical origin of various terms in the expression for current.     

Angular distribution in ternary fission

The angular distribution of long-range alpha particles emitted in keV-neutron induced fission of²³⁵U has been measured using a technique which employs only a particle telescope to derive the angular information. The neutron energy region investigated is 100 keV-1 MeV. The angular distribution oflras has been found to be peaked perpendicular to the neutron-direction with a substantial amount of anisotropy near 200 keV.     

deSitter space-time and rotation

A metric containing a parameterb is presented. It represents two distinct families of space-times, the Taub-nut family and the deSitter family, according asb=1 andb=4 respectively. The metric of the deSitter family of space-times contains a further parameterm. Whenm=0, the space-time is the usual homogeneous and isotropic deSitter space-time. But ifm≠0, the metric represents a space-time which is homogeneous but not isotropic satisfyingR _ik =Λg _ik . In this space-time, the 4-velocity of an observer at rest will have non-zero twist. The metric withb=4,m≠0 is interpreted as a metric representing a “rotating deSitter space-time”.     

Distance-dependent fluorescence quenching ofN-acetyl-l-tryptophanamide by acrylamide

We examined the time-dependent intensity decays ofN-acetyl-l-tryptophanamide (NATA) when collisionally quenched by acrylamide in propylene glycol over a range of temperatures. The intensity decays of NATA became increasingly heterogeneous in the presence of acrylamide. The NATA intensity decays were not consistent with the Collins-Kimball radiation boundary condition (RBC) model for quenching. The steady-state Stern-Volmer plots show significant upward curvature, and quenching of NATA by acrylamide was observed even in vitrified propylene glycol, where translational diffusion cannot occur during the lifetime of the excited state. These frequencydomain and steady-state data indicate a through-space quenching interaction between NATA and acrylamide, and the results are consistent with a rate constant for quenching that depends exponentially on the fluorophore-quencher separation distance. The exponential distance-dependent rate of quenching also explains the upward curvature of the Stern-Volmer plot, and the steady-state data aid in determining the interaction distance between NATA and acrylamide. These results suggest that the distance-dependent quenching rates need to be considered in the interpretation of acrylamide quenching of proteins.     

Change of confinement scale in nuclei and the EMC effect

We study a model in which the confinement scale of quarks in a nucleus of massA changes asA ^1/3. This explains theA dependence of structure functions (emc effect) as seen in muon, electron and antineutrino deep inelastic scattering from nuclear targets. We also investigate a prediction of this model—anA dependence of theqcd scale parameter A.     

Approximate angular momentum projection from an intrinsic random phase approximation Hartree-Fock state

An approximation procedure is described to calculate the projected energies from an intrinsicrpa hf wave function. The method of moments is used to find the relevant parameters. A model calculation is carried out for illustrative purposes.     

Electrical second harmonic generation in the autostabilized state of ferroelectric solid solutions (lead,strontium) titanate and (lead,calcium) titanate

tandel effect and second harmonic generation studies on ferroelectric solid solutions (lead, strontium) titanate and (lead, calcium) titanate were carried out near the Curie temperature. The generated second harmonics are linear for low biasing fields with a zero off-set, while they decrease sharply at higher biasing fields. In the autostabilized state, thetandel elements adjust their impedance against the variations of a.c. field. Zero off-set might have been caused due to the presence of delects giving rise to an internal bias which in turn generates second harmonic.     

Ga0.47 In0.53 As—The material for high-speed devices

Electron transport properties of Ga_0.47In_0.53As are reviewed. The available physical constants of the material and results on electron mobility in bulk materials, 2deg systems and under hot-electron conditions are presented. Applications of the material in the construction offet’s and photo-conductive detectors are briefly discussed.     

Electron energy loss spectroscopy (eels) of organic molecules in vapour phase: Design and fabrication of an indigenouseel spectrometer

An indigenous electron energy loss spectrometer has been designed and fabricated for the study of free molecules. The spectrometer enables the recording of low-resolution electronic spectra of molecules in the vapour phase with ready access to the vacuum ultraviolet region. Electron energy loss spectra of aliphatic alcohols and carbonyl compounds as well as of benzene derivatives have been recorded with the indigenous spectrometer and the electronic transitions in these molecules discussed. Contribution No. 274 from the Solid State and Structural Chemistry Unit, dedicated to Dr. Raja Ramanna on his 60th birthday.     

Electrical and photoelectrical studies of plasma polymerized acrylonitrile

The electrical and photoelectrical properties of plasma polymerized acrylonitrile (PAN) are reported. The polymer films were studied in silver-PAN-silver systems. Electrical conductivity at room temperature was of the order of 10⁻¹¹ ohm⁻¹ cm⁻¹. The space charge limited current (SCLC) studies at room temperature and thermally stimulated current studies (TSC) over a temperature range of 290–500°K led to a clear understanding of carrier concentration, carrier mobility, trapping levels and activation energies. Photoelectric measurements were used to draw a band picture in plasma depositedPAN.     

EXAFS study of intermetallics of the type RGe2 (R=La,Ce, Pr,Nd, Sm,Gd, Tb,Dy, Ho,Er and Y) Part II: Determination of Ge-R distances

The extended x-ray absorption fine structure (EXAFS) associated with the GeK x-ray absorption discontinuity in pure germanium and in the intermetallics RGe₂ (R=La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er and Y) has been studied. The Ge-R distances in these compounds have been determined by comparing the experimental phase shifts with the theoretical ones. The Ge-R distances in the compounds TbGe₂, HoGe₂ and ErGe₂ are being reported for the first time in this work.