Botha, E C; Odendaal, J W; Geggus, K M(Microwave and Optical Technology Letters, February 20, 1998)
[+]
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Abstract:
Compact-range radar backscatter measurements are taken
of aircraft scale models. In addition, computer software is used to predict
the RCS of the aircraft. Synthetic down-range profiles formed from the
two sources of backscatter data are compared and visualized in an
innovative manner. Similar discrimination rates between the two aircraft
are obtained on data from both source
Sugunan, Sankaran; Binitha, N N(React Kinet.Catal.Lett.& Akademiai Kiado, March 27, 2008)
[+]
[-]
Abstract:
Linear alkylbenzene sulfonic acid, the largest-volume synthetic surfactant, in addition to its excellent performance , is important due to its biodegradable environmental friendliness, as it has a straight chain and is prepared by the sulphonation of linear alkylbenzenes (LAB). To ensure environmental protection, the commercial benzene alkylation catalysts HF or AICI3 are replaced and we have developed a clean LAB production process using a pillared clay catalyst capable of not only replacing the conventional homogeneous catalyst, but also having high selectivity for the best biodegradable 2-phenyl LAB isomer .Pillared clay catalysts having high Bronsted acidity show efficient conversion in gas phase alkylation of benzene with 1-octene with a good 2-phenyl octane selectivity.
Jyothi, T M; Rao, B S; Sugunan, S; Sreekumar, K(Indian Journal of Chemistry, December , 1999)
[+]
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Abstract:
Alkylation of phenol with methanol has been carried out over
Sn-La and Sn-Sm mixed oxides of varying compositions at 623 K
in a vapour phase flow reactor. It is found that the product
selectivity is greatly influenced by the acid-base properties of the
catalysts. Ortho-cresol formation is favoured over catalysts with
weak acid sites whereas formation of 2,6-xylenol occurs in the
presence of stronger acid sites. The cyclohexanol decomposition
reaction and titrimetric method using Hammett indicators have
been employed to elucidate the acid-base properties of the
catalysts.
Description:
Indian Journal of Chemistry
Vol. 38A, December 1999, pp. 1253-1255
Pius S,Padayatti; Paulose,C S(Department of Biotechnolgy, April 2, 1999)
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Abstract:
The brain stems (13S) of streptozotocin (STZ)-diabetic rats were studied lo see the changes in
neurotransmitter content and their receptor regulation. The norepinephrine (NE) content
determined in the diabetic brain stems did ^ control. an E showed la
while
PI turnover
hri
content increased significantly compared N^r eNveFa o the recep
significant increase. The alpha2 adrenergic receptor
IneP utisoulinntreat d ratsetheNE contentt dec^ sled
was significantly reduced during diabetes. in
versedcto reanorm
sed
ulcrea e tK
reatment
the
state.
while EPI content remained increased as in die diabetic
B,, for a]pha2 adrenergic receptors slw^nificantly while
Unlabelled clonidine inhibited [31-I]NE binding in BS of control, diabetic and insulin treated
ulations bindi
diabetic rats showed that alpha2 adrenergicre^ punks cojnidiabetic animal the ligand bound
sites with Hill slopes significantly away from unity.
weaker to the low affinity site than in controls. Insulin treatment reversed[ this allumbmn to
control levels. The displacement analysis using (-)-epinephrine age in
control and diabetic animals revealed two populations of receptor affinidtyo=tat ss. In control
animals, when GTP analogue added with epinephrine, the curve nagnlde caofnfitnroit yS
model; but in the diabetic BS this effect `not
aobserved. In
bintact
oth the diabetic
data thus showlthat
the effects of monovalent cations on affinity
alphaz adrenergic receptors have a reduced affinity v
due
in stem ialtered Itscppeomson(5-
regulation. The serotonin (5-HT) coat
hydroxy) tryptophan (5-HTP) showed an increase and its breakdown metabolite (5-hydroxy)
indoleacetic acid (5-I{IAA) showed a significant decrease. This showed that in serotonergic
which l
nerves there is a disturbance in both synthetic and breankduomwnbers pretma'med ana
increased 5-HT. The high affinity serotonin receptor um ese serotonerg
decrease in the receptor affinity. The insulin ^treatmentsturtiy showsha decreased serotonergic
receptor kinetic parameters to control level.
receptor function. These changes in adrenergic and serotonergic receptor function were
suggested to be important in insulin function during STZ diabetes.
Viswanathan,M; Paulose,C S; Lal,K J; Sharma,S K; Dakshinamurti,K(Department of Biotechnology, November 27, 1989)
[+]
[-]
Abstract:
Moderate pyridoxine deficiency in adult male Sprague-Dawley rats results in significant hypertension,
associated with a general sympathetic stimulation , including an increase in the turnover of norepinephrine
in the heart. Treatment of these rats with pyridoxine reversed blood pressure to normal within 24 h. Treatment
of pyridoxine-deficient rats with clonidine or x-methyl dihydroxyphenylalanine (x-methyl DOPA)
also reduced the blood pressure of these animals to normal . There was also a significant increase in the
Bma, of high and low affinity [3H]p-amino-clonidine binding to crude synaptosomal membrane preparations
of the brain stem of deficient rats indicating chronic underexposure of)(, adrenoreceptors to endogenous
norepinephrin.
Renuka, T R; Ani Das, V; Paulose, C S(Department of Biotechnology, March 2, 2004)
[+]
[-]
Abstract:
Muscarinic M1 and M3 receptor changes in the brain stem during pancreatic regeneration were investigated.
Brain stem acetylcholine esterase activity decreased at the time of regeneration . Sympathetic activity also
decreased as indicated by the norepinephrine (NE) and epinephrine (EPI) content of adrenals and also in the
plasma. Muscarinic Ml and M3 receptors showed reciprocal changes in the brain stem during regeneration.
Muscairnic M1 receptor number decreased at time of regeneration without any change in the affinity. High affinity
M3 receptors showed an increase in the number. The affinity did not show any change . The number of low affinity
receptors decreased with decreased Kd at 72 hours after partial pancreatectomy. The Kd reversed to control value
with a reversal of the number of receptors to near control value . Gene expression studies also showed a similar
change in the mRNA level of Ml and M3 receptors . These alterations in the muscarinic receptors regulate
sympathetic activity and maintain glucose level during pancreatic regeneration. Central muscarinic M1 and M3
receptor subtypes functional balance is suggested to regulate sympathetic and parasympathetic activity, which in
turn control the islet cell proliferation and glucose homeostasis.
Harikrishnan, K P; Nandakumaran, V M(Elsevier, December 25, 1989)
[+]
[-]
Abstract:
This is a sequel to our earlier work on the modulated logistic map. Here, we first show that the map comes under the universality class of Feigenbaum. We then give evidence for the fact that our model can generate strange attractors in the unit square for an uncountable number of parameter values in the range μ∞<μ<1. Numerical plots of the attractor for several values of μ are given and the self-similar structure is explicity shown in one case. The fractal and information dimensions of the attractors for many values of μ are shown to be greater than one and the variation in their structure is analysed using the two Lyapunov exponents of the system. Our results suggest that the map can be considered as an analogue of the logistic map in two dimensions and may be useful in describing certain higher dimensional chaotic phenomena.
Manju,Paulson; Sona,Kundukulam O; Aanandan,C K; Mohanan,P(Microwave and Optical Technology Letters, January 20, 2002)
[+]
[-]
Abstract:
A dual-port dual-polarized compact microstrip antenna
for avoiding cross coupling between the two frequency bands is proposed
and analyzed. This antenna offers channel isolation better than 25 dB,
and is more compact compared to a conventional rectangular patch.
Analytical equations for calculating the resonant frequencies at both
ports are also presented. The theoretical calculations are verified using
experimental results
Donghyun,Kim; Sangseol,Lee(Microwave and Optical Technology Letters, July 20, 2002)
[+]
[-]
Abstract:
Most adaptive linearization circuits for the nonlinear amplifier
have a feedback loop that returns the output signal oj'tne eunplifier
to the lineurizer. The loop delay of the linearizer most be controlled
precisely so that the convergence of the linearizer should be assured lot
this Letter a delay control circuit is presented. It is a delay lock loop
(ULL) with it modified early-lute gate and can he easily applied to a
DSP implementation. The proposed DLL circuit is applied to an adaptive
linearizer with the use of a polynomial predistorter, and the simulalion
for a 16-QAM signal is performed. The simulation results show that
the proposed DLL eliminates the delay between the reference input signal
and the delayed feedback signal of the linearizing circuit perfectly,
so that the predistorter polynomial coefficients converge into the optimum
value and a high degree of linearization is achieved
A novel optical add-drop multiplexer (OADM) based on
the Mach-Zelauler interferometer (MZI) and the fiber Bragg grating
(FBG) is proposed for the first tittle to the authors ' knowledge. In the
structure, the Mach-Zehnder interferometer acts as an optical switch.
The principle of the OADM is analyzed in this paper. The OADM can
add/drop one of the multi-input channels or pass the channel directly by
adjusting the difference of the two arms of the interferometer. The channel
isolation is more than 20 dB
Aanandan,C K; K G Nair; Mohanan,P; Jacob,George(Department of Electronics, November , 1998)
[+]
[-]
Abstract:
A new compact microstrip antenna element is analyzed.
The analysis can accurately predict the resonant frequency,
input impedance, and radiation patterns. The predicted results
are compared with experimental results and excellent agreement
is observed . These antenna elements are more suitable in applications
where limited antenna real estate is available
Mohanan,P; K G Nair; Aanandan,C K; Jacob,George(Department of Electronics, 1998)
[+]
[-]
Abstract:
Abstract-A new compact microstrip antenna element is analyzed.
The analysis can accurately predict the resonant frequency,
input impedance, and radiation patterns. The predicted results
are compared with experimental results and excellent agreement
is observed . These antenna elements are more suitable in applications
where limited antenna real estate is available.
K G Nair; Aanandan,C K; Mohanan,P; Jacob,George(Department of Electronics, 1998)
[+]
[-]
Abstract:
Abstract-A new compact microstrip antenna element is analyzed.
The analysis can accurately predict the resonant frequency,
input impedance, and radiation patterns. The predicted results
are compared with experimental results and excellent agreement
is observed . These antenna elements are more suitable in applications
where limited antenna real estate is available.
Jacob,George; Aanandan,C K; Mohanan,P; K G Nair(IEEE Journals/ Transactions (USA), 1998)
[+]
[-]
Abstract:
A new compact micro strip antenna element is analyzed.
The analysis can accurately predict the resonant frequency,
input impedance, and radiation patterns. The predicted results
are compared with experimental results and excellent agreement
is observed . These antenna elements are more suitable in applications
where limited antenna real estate is available
Aanandan,C K; Mohanan,P; K G Nair; Supriyo,Dey(Department of Electronics, February 3, 1994)
[+]
[-]
Abstract:
The closed form expression for the radiated power of a half-wave
microstrip patch is modified to calculate the impedance
bandwidth of a printed dipole. Analyses of cavity backed flared
and end-loaded printed dipoles are presented
K G Nair; Aanandan,C K; Mohanan,P; Supriyo,Dey(Department of Electronics, February 3, 1994)
[+]
[-]
Abstract:
The closed form expression for the radiated power of a half-wave
microstrip patch is modified to calculate the impedance
bandwidth of a printed dipole. Analyses of cavity backed flared
and end-loaded printed dipoles are presented
Mohanan,P; K G Nair; Aanandan,C K; Supriyo,Dey(Department of Electronics, February 3, 1994)
[+]
[-]
Abstract:
The closed form expression for the radiated power of a half-wave
microstrip patch is modified to calculate the impedance
bandwidth of a printed dipole. Analyses of cavity backed flared
and end-loaded printed dipoles are presented
Supriyo,Dey; Aanandan,C K; Mohanan,P; K G Nair(Department of Electronics, November 23, 1993)
[+]
[-]
Abstract:
The closed form expression for the radiated power of a half-wave
microstrip patch is modified to calculate the impedance
bandwidth of a printed dipole. Analyses of cavity backed flared
and end-loaded printed dipoles are presented
Huo,Y; Taylor,G W(Microwave and Optical Technology Letters, May 20, 2003)
[+]
[-]
Abstract:
The operation of a previously proposed terahertz (THZ)
detector is formulated in detail. The detector is based on the hot-electron
effect of the 2D electron gas (2DEG) in the quantum well (QW) of
a GaAs/AIGaAs heterostructure. The interaction between the THz radiation
and the 2DEG, the current enhancement due to hot -electron effect, and
the noise performance of the detector are analyzed
Sona,Kundukulam O; Manju,Paulson; Aanandan,C K; Mohanan,P(Microwave Engineering Group,Department of Electronics, April 20, 2002)
[+]
[-]
Abstract:
Design equations are presented for calculating the resonance frequencies for a
compact dual frequency arrow-shaped microstrip antenna. This provides a fast and simple
way to predict the resonant frequencies of the antenna. The antenna is also analyzed using the
IE3D simulation package. The theoretical predictions are found to be very close to the
IE3D results and thus establish the validity of the design formulae