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537 PHYSICS : ELECTRICITY plasma membrane. These cells were characterized
026 CHOUDHURY, M.A. & AKHTER, S.
(Atomic Energy Centre, Dhaka). STUDY OF THE
MAGNETIC PROPERTIES OF Ni 1-XCu X Mn 0.02
Fe 1.9O 4 FERRITES. J. Bang. Acad. Sci., 2007, 31
(2), 261-266.
Copper substituted nickel ferrites have been
investigated by many worker (1-2) because of their
microwave applications. It is observed that
incorporation of Cu in nickel-ferrite lowers the
firing temperature at which the system can be
sintered which in turn helps to avoid the second
phase formation. However, ferrites containing Cu
have shown interesting electrical and magnetic
properties. (3-5) The rescarchers report here the
studies on magnetization, Curie temperature, initial
permeability and FMR line width of the Ni 1-xCu x
Mn 0. 02 Fe 19 O 4 ferrite system for x = 0, 0.1, 0.2, 0.3
and 0.4.
027 CHOWDHURY, N. ; PAL, S.G. (Dept.
of Zoology, Calcutta University, India) &
MAJUMDER, M.Z.R. (Institute of Food and
Radiation Biology, Atomic Energy Research
Establishment, Dhaka). TRANSMISSION
ELECTRON MICROSCOPIC STUDIES OF
HAEMOLYMPH CELLS OF CTENOLEPISMA
LONGICAUDATA. Bang. J. Zool., 2006, 34 (2),
195-204.
Light microscopic study revealed the occurrence of
five morphologically distinct types of haemocytes,
viz. prohaemocyte. plasmatocyte, granulocyte,
spherule cells and oenocytoids. However, electron
microscopy so far showed occurrence of
prohaemocyte, plasmatocyte and granulocyte only.
The recognition of haemocytes under Transmission
Electron Microscopy (TEM) was primarily based
on the size and shape of the cell, proportion of
nucleus and cytoplasm, presence or absence or
abundance of cyloplasmic granules. It was not
always possible to include some cells into a certain
type because the criteria employed for cell
classification did not always match with either of
the cell types. In spite of the above difficulties the
following three types of cells were recognized and
described as follows:1. Prohaemocytes were
nucleated cells, surrounded by a definite trilaminar
7
by comparatively large nucleus with scanty
cytoplasm. 2. Plasmatocytes showed a wide range
of forms such as unipolar, bipolar or even oval.
The cells were characterized by the possession of
electron dense granules of various sizes and forms
in the cytoplasm. Though most of the cells
possessed pseudopodial extensions, plasmatocytes
without pseudopodia were also not uncommon. 3.
Granulocytes were characterized by the presence
of large number of granules in the cytoplasm and
absence of conspicuous pseudopodial extensions.
Binucleate granulocytes were also evident in the
TEM studies.
028 HAQUE, M.M (Dept. of Electronics &
Applied Physics, Islamic University, Kustia).;
HUQ, M. (Dept. Physics, BUET, Dhaka) &
Hakim, M.A. (Materials Science Division,
Atomic Energy Centre, Dhaka). INITIAL
MAGNETIC PERMEABILITY AND
MAGNETIZATION STUDIES OF Mn-
SUBSTITUTED Mg-Cu-Zn SPINEL FERRITES.
J. Bang. Acad. Sci., 2007, 31 (2), 181-190.
Mn-substituted Mg 0. 35Cu 020Zn 0.45O(Fe 2. xMn xO 3) 0. 97
(x=0.0, 0.02,0.04, 0.06, 0.08 and 0.10) ferrites
have been synthesized by standard double
sintering ceramic method and characterized by X-
ray diffraction. The single-phase cubic spinel
structure of all the samples has been confirmed
from X-ray diffraction analyses. Curie
temperatures T c of the studied ferrite system has
been determined from the µ i,-T curves where
Hopkinson type of effect at the T c has been
observed with the manifestation of sharp fall of
permeability. The sharp decrease of µ i at T=T c
indicates that the samples have high homogeneity
according to Globus. The Curie temperature T c is
found to increase with increasing Mn content x.
Saturation magnetization (M s) is found to
increase with increase in Mn content up to x =
0.06 and then slightly decreases with further
increase in Mn. Initial permeability value changes
significantly with Mn addition. The values of
relative loss factor (RLF) found in the
-4
investigated ferrites are in the order of 10 , up to
frequency 2 MHz which extends to higher
frequency range as the Mn content is increased.