Lathika Cicily, Thomas; Bijoy Nandan, S(Cochin University of Science And Technology, February , 2015)
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Abstract:
The overall attempt of the study was aimed to understand the
microphytoplankton community composition and its variations along a highly
complex and dynamic marine ecosystem, the northern Arabian Sea. The data
generated provides a first of its kind knowledge on the major primary
producers of the region. There appears significant response among the
microphytoplankton community structure towards the variations in the
hydrographic conditions during the winter monsoon period. Interannually,
variations were observed within the microphytoplankton community associated
with the variability in temperature patterns and the intensity of convective
mixing. Changing bloom pattern and dominating species among the
phytoplankton community open new frontiers and vistas towards more intense
study on the biological responses towards physical processes. The production
of large amount of organic matter as a result of intense blooming of Noctiluca
as well as diatoms aggregations augment the particulate organic substances in
these ecosystem. This definitely influences the carbon dynamics of the
northern Arabian Sea. Detailed investigations based on time series as well as
trophodynamic studies are necessary to elucidate the carbon flux and
associated impacts of winter-spring blooms in NEAS. Arabian sea is
considered as one among the hotspot for carbon dynamics and the pioneering
records on the major primary producers fuels carbon based export production
studies and provides a platform for future research. Moreover upcoming
researches based on satellite based remote sensing on productivity patterns
utilizes these insitu observations and taxonomic data sets of phytoplankton for
validation of bloom specific algorithm development and its implementation.
Furthermore Saurashtra coast is considered as a major fishing zone of Indian
EEZ. The studies on the phytoplankton in these regions provide valuable raw
data for fishery prediction models and identifying fishing zones. With the
Summary and Conclusion
177
baseline data obtained further trophodynamic studies can be initiated in the
complex productive North Eastern Arabian Seas (NEAS) ecosystem that is still
remaining unexplored.
Chandra, Shekara Bhat C; Sumam, Mary Idicula; Vineetha, S(Elsevier, December 20, 2012)
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Abstract:
MicroRNAs are short non-coding RNAs that can regulate gene expression during various crucial cell processes
such as differentiation, proliferation and apoptosis. Changes in expression profiles of miRNA play an important
role in the development of many cancers, including CRC. Therefore, the identification of cancer related
miRNAs and their target genes are important for cancer biology research. In this paper, we applied
TSK-type recurrent neural fuzzy network (TRNFN) to infer miRNA–mRNA association network from paired
miRNA, mRNA expression profiles of CRC patients. We demonstrated that the method we proposed achieved
good performance in recovering known experimentally verified miRNA–mRNA associations. Moreover, our
approach proved successful in identifying 17 validated cancer miRNAs which are directly involved in the
CRC related pathways. Targeting such miRNAs may help not only to prevent the recurrence of disease but
also to control the growth of advanced metastatic tumors. Our regulatory modules provide valuable insights
into the pathogenesis of cancer
A novel antenna configuration comprised of two circular
microstrip antennas (CMAs) resonating in the TMtt and TM2, modes,
producing radiation characteristics suitable for a mobile telephone handset,
is presented. The antennas operating at the same frequency are
placed back to back with a separation comparable to the thickness of a
typical handset. The radiation pattern consists of a region of reduced
radiation intensity, which minimizes the radiation hazards to the user
Description:
Microwave and Optical Technology Letters,VOL 23,issue 6.pp 370-372
Mridula, S; Jacob,George; Mohanan, P(Microwave and Optical Technology Letters, December 20, 1999)
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Abstract:
A novel antenna configuration comprised of two circular
micro strip antennas (CMAs) resonating in the TMtt and TM2, modes,
producing radiation characteristics suitable for a mobile telephone handset,
is presented. The antennas operating at the same frequency are
placed back to back with a separation comparable to the thickness of a
typical handset. The radiation pattern consists of a region of reduced
radiation intensity, which minimizes the radiation hazards to the user
Jitha, B; Bybi, P C; Aanandan,C K; Mohanan, P(John Wiley & Sons, June , 2008)
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Abstract:
Design of a compact microstrip band reject filter is proposed. The device consists of an Open Loop Rectangular Resonator (OLRR) coupled to a microstrip line. The transmission line has a U-bend which enhances the coupling with the OLRR element and reduces the size of the filter. The filter can be made tunable by mounting variable capacitance to the system. Simulated and experimental results are presented.
Zhongyou,Yan(Microwave Engineering Group,Department of Electronics, January 5, 2002)
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Abstract:
patch resonator with a via connecting ground plane is
proposed and studied experimentally. The resonant frequency of this
patch resonator is tunable up to about 34 % by adjusting the via position
in the center line. The lowest resonant frequency of this patch resonator
has been reduced by more than 64% of the same size patch resonator
Anantharaman, M R; Senoy, Thomas; Al-Harthi, S H; Sakthi Kumar, D; Al-Omari, I A; Ramanujan, R V; Yasuhiko, Yoshida(IOP Publishing LTD, July 17, 2008)
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Abstract:
Nanocrystalline Fe–Ni thin films were prepared by partial crystallization of vapour deposited
amorphous precursors. The microstructure was controlled by annealing the films at different
temperatures. X-ray diffraction, transmission electron microscopy and energy dispersive x-ray
spectroscopy investigations showed that the nanocrystalline phase was that of Fe–Ni. Grain
growth was observed with an increase in the annealing temperature. X-ray photoelectron
spectroscopy observations showed the presence of a native oxide layer on the surface of the
films. Scanning tunnelling microscopy investigations support the biphasic nature of the
nanocrystalline microstructure that consists of a crystalline phase along with an amorphous
phase. Magnetic studies using a vibrating sample magnetometer show that coercivity has a
strong dependence on grain size. This is attributed to the random magnetic anisotropy
characteristic of the system. The observed coercivity dependence on the grain size is explained
using a modified random anisotropy model
Anantharaman, M R; Vinayasree, S; Soloman, M A; Vijutha, Sunny; Mohanan, P; Philip, Kurian(Elsevier, April 21, 2013)
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Abstract:
Flexible and thin single layer microwave absorbers based on strontium ferrite–carbon black–nitrile rubber
composites have been fabricated employing a specific recipe and their reflection loss characteristics
were studied in the S (2–4 GHz) and X-bands (8–12 GHz). The incorporation of carbon black not only
reinforces the rubber by improving the mechanical properties of the composite but also modifies the
dielectric permittivity of the composite. Strontium ferrite when impregnated into a rubber matrix
imparts the required magnetic permeability to the composite. The combination of strontium ferrite
and carbon black can then be employed to tune the microwave absorption characteristics of the resulting
composite. The complex dielectric permittivity and permeability were measured by employing a cavity
perturbation technique. The microwave absorption characteristics of composites were modelled in that
an electromagnetic wave incident normally on the metal terminated single layer absorber. The influence
of filler volume fraction, frequency, absorber thickness on the bandwidth of absorption are discussed and
correlated
Anantharaman, M R; Vamsi Krishna, G; Philip, Kurian(2013)
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Abstract:
Ferrite composites are magnetic composites consisting of fine particles of metal
ferrites dispersed in the polymer matrix. These composites have a variety of applications as
flexible magnets, pressure/photo sensors and microwave absorbers. Polymers and
magnetic materials play a very important role in our day to day life. Both natural and
synthetic polymers are today indispensable to mankind. The polymers, which include
rubber, plastics and fibers, make life easier and more comfortable.
A microwave dielectric ceramic resonator based on BaCe2Ti5O15 and Ba5Nb4O15 have been prepared by conventional solid state ceramic route. The dielectric resonators (DRs) have high dielectric constant 32 and 40 for BaCe2Ti5O15 and Ba5Nb4O15, respectively. The whispering gallery mode (WGM) technique was employed for the accurate determination of the dielectric properties in the microwave frequency range. The BaCe2Ti5O15 and Ba5Nb4O15 have quality factors (Q X F) of 30,600 and 53,000 respectively. The quality factor is found to depend on the azimuthal mode numbers. The temperature coefficient of resonant frequency (Tr) of BaCe2Ti5O15 and Ba5Nb4O15 have been measured accurately using different
resonant modes and are + 41 and + 78 ppm/K, respectively
The microwave dielectric properties of (I -x)CaTiO3-xSm(Mg1/2Tit,2)O3(0.1 <-x< 1.0) have been investigated. The
system forms a solid solution throughout the entire compositional range. The dielectric constant decreases from 86 to 25 as x
varies from 0.1 to 1.0. The Qxf varies non-linearly and increases for composition with x> 0.6. The nonmonotonic variation
with composition x is more pronounced in Tt than in er. The microwave dielectric properties indicate the possibility of a phase
transformation for x between 0.4 and 0.5
microwave dielectric properties of ceramics based on Ba(Mgv3Ta(2-2x)t3W,t3Tixt3)O3 is investigated as a function of x. The
15 densification as well as dielectric properties deteriorate with increase in the substitution levels of (Ti 1,3W113)333 + at (Ta213)3.33+ site
16 in Ba(Mg113Ta213)03. The rt is approaching zero between x = 0.1 and 0.15 in Ba(Mg it3Ta(2-2,,.)t3W,it3Ti,Tt3)O3 where quality factor is
17 reasonably good (Qu x f = 80,000-90,000 GHz). The Ba(Mg1,3Ta(2_,013W,13Ti,,13)03 with x = 1.0 has e, = 15.4, rf= -25.1 ppm/
18 "C, Q„ x f = 35,400 GHz
The BaO-2CeO2-nTiO2 ceramics with n = 3, 4 and 5 have been prepared with CeO2 as starting material . The ceramics have been
characterized using scanning electron microscopy , X-ray diffraction , Raman and X-ray photoelectron spectroscopy techniques. The
microwave dielectric properties have been measured using standard dielectric resonator techniques . BaO-2CeO2-3TiO2 (123),
BaO-2CeO2-4TiO2 ( 124) and BaO-2CeO2-5TiO2 ( 125) ceramics showed dielectric constants of 38, 27 and 32, respectively . All the
ceramics showed fairly good unloaded Q - factors . 124 and 125 compounds exhibited low tf values, while 123 showed a high rf value
Isuhak, Naseembeevi Jawahar; Narayana Iyer, Santha; Mailadil, Thomas Sebastian(Materials Reserach Society, December , 2002)
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Abstract:
Single-phase polycrystalline ceramics in the MO-La2O3-Ti02 (M = Ca, Sr, Ba)
system, such as cation-deficient hexagonal perovskites CaLa4Ti4O15, SrLa4Ti4O15,
BaLa4Ti4O15, and Ca2La4Ti5O18 and the orthorhombic phases CaLa4Ti5O17 and
CaLa8Ti9O31, were prepared through the solid-state ceramic route. The phases
and structure of the ceramics were analyzed through x-ray diffraction and scanning
electron microscopy. The microwave dielectric properties of the ceramics were studied
using a network analyzer. The investigated ceramics show high Er in the range 42 to
54, high quality factors with Q x f in the range 16,222 to 50,215 GHz, and low Tf in
the range -25 to +6 ppm3/°C. These high dielectric constant materials with high Q x f
up to 50,215 GHz are suitable for applications where narrow bandwidth and extremely
low insertion loss is necessary, especially at frequencies around 1.9 GHz
Microwave dielectric ceramics based on RETiTaO6 (RE = La, Cc, Pr, Nd, Sm, Eu,
Gd, Tb, Dy, Ho, Y, Er, Yb, Al, and In) were prepared using a conventional solid-state
ceramic route. The structure and microstructure of the samples were analyzed using
x-ray diffraction and scanning electron microscopy techniques. The sintered samples
were characterized in the microwave frequency region. The ceramics based on Ce, Pr,
Nd, Sm, Eu, Gd, Tb, and Dy, which crystallize in orthorhombic aeschynite structure,
had a relatively high dielectric constant and positive T f while those based on Ho, Er,
and Yb, with orthorhombic euxenite structure, had a low dielectric constant and
negative Tf. The RETiTaO6 ceramics had a high-quality factor. The dielectric constant
and unit cell volume of the ceramics increased with an increase in ionic radius of the
rare-earth ions, but density decreased with it. The value of Tf increased with an
increase in RE ionic radii, and a change in the sign of Tf occurred when the ionic
radius was between 0.90 and 0.92 A. The results indicated that the boundary of the
aeschynite to euxenite morphotropic phase change lay between DyTiTaO6 and
HoTiTaO6. Low-loss ceramics like ErTiTaO6 (Er = 20.6, Qxf = 85,500), EuTiTaO6
(Er = 41.3, Qxf = 59,500), and YTiTaO6 (Er = 22.1, Q„xf = 51,400) are potential
candidates for dielectric resonator applications
Dielectric resonator ceramics with composition formula Ba[(D3+0.3 Bi0.2)Nb0.5]O3,where D3+=Y,Pr,Sm,Gd,Dy and Er,were prepared by the conventional ceramic preparation route