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029 RAHMAN, M.J.; CHOUDHURY, S. Sylhet). VARIATIONAL MONTE CARLO
(Dept. of Physics, Dhaka University, Dhaka); CALCULATIONS FOR THE BINDING ENERGY
BHUIYAN, A.H. (Dept. of Physics, BUET, DIFFERENCE OF THE HYPERNUCLEAR ISO-DOUBLET
H ^ - He ^. J. Bang. Acad. Sci., 2006, 30 (2), 159-165.
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Dhaka); RAHMAN, S.N. (Industrial Physics
Division, BCSIR, Dhaka) & KHAN, A.H. (Dept. The binding energies of hypernuclear iso-doublet
of Physics, Jahangirnagar University, Savar, 4 H ^ - He ^.have been calcutated variationally taking
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Dhaka). ELECTRICAL PROPERTIES OF the hypernuclei as the (Λ+p+n+n) and (Λ+n+p+p)
CERIUM DOPED BARIUM TITANATE. J. four-body models, respectively. Two different
Bang. Acad. Sci., 2007, 31 (1), 137-141. types of potentials such as Gaussian and Urbana
were used in each case. A three-body Wigner-type
Barium titanate (BaTiO 3) and cerium (Ce) doped potential was also taken into account with each of
barium titanate samples with general formula Ba 1- the above two potentials. The calculated binding
xCe x TiO 3 (where x = 0.0, 0.1, 0.2, 0.3, and 0.4) energy difference came as 0.33 and 0.33 MeV,
were prepared by solid-solid ceramic method at the respectively for the Gaussian and Urbana type
sintering temperature of 1250°C. 1-V characteristics potentials as against the experimental value of
of pure and Ce-doped BaTiO3 show ohmic 0.34±0.07 MeV. Results are within acceptable
behavior with two distinct slopes. At the higher limits. Results also compare well with other
voltage region receptivity of the samples is of the theoretical calculations. The binding energy
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order of 10 Ω-cm. The de receptivity variation of difference obtained in the present work reflects the
BaTiO 3 with temperature shows a transition from charge symmetry breaking in the Λ N interation.
tetragonal to cubic structure at about 120°C. The
Curie temperature of Ba 1-xCe xTiO 3 decreases 032 CHOWDHURY, M.Z.A. & SHYAM,
linearly with the increase of Ce. L.K. (Dept. of Chemistry, University of
Chittagong, Chittagong). EFFECT OF SAME-
539 PHYSICS : NUCLEAR SCIENCE SYMMETRY ATTRACTION ON THE BOND
LENGTH OF AB 3 MOLECULES. J. Bang. Acad.
030 ALAM, M.K. (Institute of Nuclear Sci,, 2006, 30 (2), 225-231.
Science & Technology, Atomic Energy Research
Establishment, Savar, Dhaka). NEW HORIZON The three A-B bonds in both pyramidal and planar
OF LANGMUIR WAVE AND ALFVEN WAVE. AB 3 molecules are found to the equal in length and
J. Bang. Acad. Sci., 2006, 30 (1), 1-7. this equality is explained by the attractions of those
valence orbitals which have the same-symmetry
The effects of dust charge fluctuation on a properties. The central atoms in such molecules
Langmuir wave, the symmetry of electrosound employ s and (P x, p y) orbitals for bonding where the
speed and torsional Alfven speed have studied. In s orbital is at a lower energy than the (p x, p y) set. In
that case the dispersion relation has been deduced the pyramidal AB 3 molecules, a non-bonding p z
in presence of massive dust grains. For the orbital has the same symmetry property (a 1) as the
presence of stationary and charging-discharging of bondling s orbital. The symmetry attraction of this
dust grains the researchers have analyzed growth P z orbital elevates the energy of S orbital so thai it
rate/damping rate of Langmuir wave. It is observed comes closer to that of (p x, p y) set This energy
that due to the presence of dust particles, at the cut- elevation is expected to be responsible for making
off condition the electrosound speed must be equal the three bonds equal in all pyramidal AB 3
to the speed of torsional Alfven wave. molecules. Similarly, in the planar AB 3 molecules
of transition metals, a non-bonding (d xy, d x2 - y2)
031 ALAM, M.K. (Institute of Nuclear set has the same symmetry property (e) as the
Science & Technology, Bangladesh Atomic bonding (p x, p y) set. The symmetry-attraction of
Energy Commission, Dhaka); ZAMAN, M.A. this non-bonding set causes a depression on the
(Dept. of Physics, Jahangirnagar University, Savar, bonding set so that (p x,p y) comes closer to the s
Dhaka) & AHSAN, M. H. (Dept. of Physics, orbital to form ihrce equal A-B bonds in the planar
Shahjalal University of Science & Technology, AB 3 molecules which have transition metals in
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