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101.
In this paper, we propose the implementation of waveguide-coupled ring resonators in photonic crystal integrated circuits. Using two-dimensional finite difference time domain (2D FDTD) method, we study the spectral characteristics of a waveguide-coupled ring carved in two-dimensional photonic crystal of square lattice (2D SLPC) and based on the results, we suitably modify the structure geometry to establish its performance as a ring resonator. We further investigate the effects of ring dimension and crystal parameters on the resonance properties of the ring resonator. 相似文献
102.
103.
104.
M D Srinivas 《Pramana》1982,19(2):159-173
This paper is devoted to a study of some of the basic conditions which have to be satisfied by a hidden variable theory in
order that it can reproduce the quantum mechanical probabilities. Of course one such condition, which emerges from the important
theorem of Bell, is that a hidden variable theory has to be non-local. It is shown that a hidden variable theory is also incompatible
with the conventional interpretation of mixed states and the mixing operation in quantum theory. It is therefore concluded
that, apart from being non-local, a hidden variable theory would also necessarily violate the usual assumption of quantum
theory that the density operator provides an adequate characterization of any ensemble of systems, pure or mixed. 相似文献
105.
G. Naga Srinivas Hotha Srinivas Eluvathingal D. Jemmis 《Journal of Chemical Sciences》1994,106(2):169-181
The reactivity centres of Ti8C12, for the three structures suggested in conformity with experimental observations, are studied by extended Huckel theory,
The C2 unit can complex with transition metal fragments such as Pt(PH3)2 with the unusual net result of transferring two electrons to Ti8C12. The metal centre, Ti can accommodate extra two-electron donors like CO. Model systems are used to explain the carbon and
metal environment in Ti8C12. 相似文献
106.
Using polarised neutrons, the full three-dimensional magnetic structure amplitudes in the Ni1?c Ru c single crystals forc = 0·027, 0·033 and 0·046 were measured. Moment density maps in various portions of the Wigner-Seitz cell were obtained. It is seen from these maps that unlike Ni-based alloys with 3d impurities, the introduction of Ru to the Ni matrix produces extensive perturbations in the diffuse moment density, giving rise to a netpositive diffuse moment which tends to increase with Ru concentration. The asphericity of the host moment at first increases and then decreases with increasing Ru content. Another significant outcome of the present study is the evidence for the reversal of the sign of the Ru moment, from negative to positive, obtained by comparing the shape of the spherical site form factors of the three-alloy concentrations with the Ni spherical form factor itself. The sign reversal of the impurity moment is confirmed by the form factor analyses. Strong local environmental effects seem to play a major role in this alloy system. 相似文献
107.
A polarised neutron study of the ferromagnetic Heusler alloy Cu2Mn0.863Al1.057 has been made. It has been concluded that the magnetic moment density is primarily situated on the Mn ions. On assigning
the Mn-moment value, the observed magnetic form factor is found to be in good agreement with the Mn2+ free ion form factor calculated by Watson and Freeman. A slight asphericity has been observed in the moment density. It is
estimated that there are about 3% excess 3d-electrons in the Eg states compared to spherical distribution. There is evidence of a very small positive polarisation of
the Cu atoms. No appreciable conduction electron polarisation is found. 相似文献
108.
Lopez CF Nielsen SO Srinivas G Degrado WF Klein ML 《Journal of chemical theory and computation》2006,2(3):649-655
Knowledge of the mechanism of action of antimicrobial agents is crucial for the development of new compounds to combat microbial pathogens. To this end, computational studies on the interaction of known membrane-active antimicrobial polymers with phospholipid bilayers reveal spontaneous membrane insertion and cooperative action at low and high concentrations, respectively. In late-stage attack, antimicrobials cross the membrane core and occasionally align to provide a stepping-stone pathway for water permeation; this suggests a possible new mode of action that does not depend on pore formation for transport to and across the inner leaflet. The computations rationalize the observed activity of a new class of antimicrobial compounds. 相似文献
109.
S. Srinivas Rau 《Israel Journal of Mathematics》1991,76(1-2):229-235
We give an elementary proof of continuity of the determinant in the parameter for a smooth family of laplacians (of the same
nullity) on a smooth family of holomorphic vector bundles over a compact complex manifold. Families of unitary flat bundles
over a compact Riemann surface are discussed, as an example. 相似文献
110.
Apart from serving as a parameter in describing the evolution of a system, time appears also as an observable property of
a system in experiments where one measures ‘the time of occurrence’ of an event associated with the system. However, while
the observables normally encountered in quantum theory (and characterized by self-adjoint operators or projection-valued measures)
correspond to instantaneous measurements, a time of occurrence measurement involves continuous observations being performed
on the system to monitor when the event occurs. It is argued that a time of occurrence observable should be represented by
a positive-operator-valued measure on the interval over which the experiment is carried out. It is shown that while the requirement
of time-translation invariance and the spectral condition rule out the possibility of a self-adjoint time operator (Pauli’s
theorem), they do allow for time of occurrence observables to be represented by suitable positive-operator-valued measures.
It is also shown that the uncertainty in the time of occurrence of an event satisfies the time-energy uncertainty relation
as a consequence of the time-translation invariance, only if the time of occurrence experiment is performed on the entire
time axis. 相似文献