1,022 research outputs found
Single-, Dual- and Triple-band Frequency Reconfigurable Antenna
The paper presents a frequency reconfigurable slot dipole antenna. The antenna is capable of being switched between single-band, dual-band or triple-band operation. The antenna incorporates three pairs of pin-diodes which are located within the dipole arms. The antenna was designed to operate at 2.4 GHz, 3.5 GHz and 5.2 GHz using the aid of CST Microwave Studio. The average measured gains are 1.54, 2.92 and 1.89 dBi for low, mid and high band respectively. A prototype was then constructed in order to verify the performance of the device. A good level of agreement was observed between simulation and measurement
Representations of Quantum Bicrossproduct Algebras
We present a method to construct induced representations of quantum algebras
having the structure of bicrossproduct. We apply this procedure to some quantum
kinematical algebras in (1+1)--dimensions with this kind of structure:
null-plane quantum Poincare algebra, non-standard quantum Galilei algebra and
quantum kappa Galilei algebra.Comment: LaTeX 2e, 35 page
Interacting Growth Walk - a model for hyperquenched homopolymer glass?
We show that the compact self avoiding walk configurations, kinetically
generated by the recently introduced Interacting Growth Walk (IGW) model, can
be considered as members of a canonical ensemble if they are assigned random
values of energy. Such a mapping is necessary for studying the thermodynamic
behaviour of this system. We have presented the specific heat data for the IGW,
obtained from extensive simulations on a square lattice; we observe a broad
hump in the specific heat above the -point, contrary to expectation.Comment: 4 figures; Submitted to PR
Stevens Johnson syndrome in Pakistan: a ten-year survey
Objective: A pre-tested questionnaire-based, retrospective study to highlight the causative factors, mode of presentation, complications and outcome of patients with Stevens Johnson syndrome.SETTING: Aga Khan University Hospital over a 10 year period.Methods: All case records with a diagnosis of Steven Johnson Syndrome in the period 1990 to 2000 were retrospectively reviewed. Data was retrieved on a comprehensive questionnaire. The demographic variatbles and drugs taken within the previous 21 days were noted. Date analysis was done by Epi-Info Version 6.0.Results: Of the 101 studied patient files, the most common offender was found to be the Penicillins as a group and Sulfadoxine-Pyrimethamine (Fansidar) when considering all drugs individually. Most common complications included electrolyte disturbances (13.9%) and congestive heart failure (6.9%). Mortality rate was high at 10.1%.CONCLUSION: SJS was found to be a rare condition but having a mortality rate of 10.1%. As it can be induced by a large number of drugs, caution should be practiced while prescribing
Dynamic Scaling of an Adsorption-Diffusion Process on Fractals
A dynamic scaling of a diffusion process involving the Langmuir type
adsorption is studied. We find dynamic scaling functions in one and two
dimensions and compare them with direct numerical simulations, and we further
study the dynamic scaling law on fractal surfaces. The adsorption-diffusion
process obeys the fracton dynamics on the fractal surfaces.Comment: 9 pages, 7 figure
Lagrangian and Hamiltonian Formalism on a Quantum Plane
We examine the problem of defining Lagrangian and Hamiltonian mechanics for a
particle moving on a quantum plane . For Lagrangian mechanics, we
first define a tangent quantum plane spanned by noncommuting
particle coordinates and velocities. Using techniques similar to those of Wess
and Zumino, we construct two different differential calculi on .
These two differential calculi can in principle give rise to two different
particle dynamics, starting from a single Lagrangian. For Hamiltonian
mechanics, we define a phase space spanned by noncommuting
particle coordinates and momenta. The commutation relations for the momenta can
be determined only after knowing their functional dependence on coordinates and
velocities.
Thus these commutation relations, as well as the differential calculus on
, depend on the initial choice of Lagrangian. We obtain the
deformed Hamilton's equations of motion and the deformed Poisson brackets, and
their definitions also depend on our initial choice of Lagrangian. We
illustrate these ideas for two sample Lagrangians. The first system we examine
corresponds to that of a nonrelativistic particle in a scalar potential. The
other Lagrangian we consider is first order in time derivative
Implementation of MPI environment for solving large systems of ODEs using block method.
Parallel 2-point and 3-point block method will simultaneously compute the numerical solutions at two and three points respectively are suitable for solving large system of first order ordinary differential equations (ODEs) using variable step size. The Gauss Seidel iteration will be implemented for the block methods. The parallelism across the system is considered for the parallelization of the proposed methods using the Message Passing Interface (MPI) communication environment which runs on High Performance Computing (HPC). Numerical examples are given to illustrate the efficiency of the parallel implementation of the proposed method using 2, 4 and 6 processors with respect to the sequential one
Effect of quantum group invariance on trapped Fermi gases
We study the properties of a thermodynamic system having the symmetry of a
quantum group and interacting with a harmonic potential. We calculate the
dependence of the chemical potential, heat capacity and spatial distribution of
the gas on the quantum group parameter and the number of spatial dimensions
. In addition, we consider a fourth-order interaction in the quantum group
fields , and calculate the ground state energy up to first order.Comment: LaTeX file, 20 pages, four figures, uses epsf.sty, packaged as a
single tar.gz uuencoded fil
q-Functional Wick's theorems for particles with exotic statistics
In the paper we begin a description of functional methods of quantum field
theory for systems of interacting q-particles. These particles obey exotic
statistics and are the q-generalization of the colored particles which appear
in many problems of condensed matter physics, magnetism and quantum optics.
Motivated by the general ideas of standard field theory we prove the
q-functional analogues of Hori's formulation of Wick's theorems for the
different ordered q-particle creation and annihilation operators. The formulae
have the same formal expressions as fermionic and bosonic ones but differ by a
nature of fields. This allows us to derive the perturbation series for the
theory and develop analogues of standard quantum field theory constructions in
q-functional form.Comment: 15 pages, LaTeX, submitted to J.Phys.
Enhanced production of poly (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer with manipulated variables and its properties
Cupriavidus sp. USMAA1020, a local isolate was able to biosynthesis poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] copolymer with various 4HB precursors as the sole carbon source. Manipulation of the culture conditions such as cell concentration, phosphate ratio and culture aeration significantly affected the synthesis of P(3HB-co-4HB) copolymer and 4HB composition. P(3HB-co-4HB) copolymer with 4HB compositions ranging from 23 to 75 mol% 4HB with various mechanical and thermal properties were successfully produced by varying the medium aeration. The physical and mechanical properties of P(3HB-co-4HB) copolymers were characterized by NMR spectroscopy, gel-permeation chromatography, tensile test, and differential scanning calorimetry. The number-average molecular weights (M (n)) of copolymers ranged from 260 x 10(3) to 590 x 10(3)Da, and the polydispersities (M (w)/M (n)) were between 1.8 and 3.0. Increases in the 4HB composition lowered the molecular weight of these copolymers. In addition, the increase in 4HB composition affected the randomness of copolymer, melting temperature (T (m)), glass transition temperature (T (g)), tensile strength, and elongation to break. Enzymatic degradation of P(3HB-co-4HB) films with an extracellular depolymerase from Ochrobactrum sp. DP5 showed that the degradation rate increased proportionally with time as the 4HB fraction increased from 17 to 50 mol% but were much lower with higher 4HB fraction. Degradation of P(3HB-co-4HB) films with lipase from Chromobacterium viscosum exhibited highest degradation rate at 75 mol% 4HB. The biocompatibility of P(3HB-co-4HB) copolymers were evaluated and these copolymers have been shown to support the growth and proliferation of fibroblast cells
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