20,165 research outputs found

    High-spin structure and Band Termination in 103^{103}Cd

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    Excited states of the neutron deficient 103^{103}Cd nucleus have been investigated via the 72^{72}Ge(35^{35}Cl, p3n) reaction at beam energy of 135 MeV by use of in-beam spectroscopic methods. Gamma rays depopulating the excited states were detected using the Gammasphere spectrometer with high-fold γ\gamma-ray coincidences. A quadrupole γ\gamma-ray coincidence analysis (γ4\gamma^{4}) has been used to extend the known level scheme. The positive parity levels have been established up to J=35/2J = 35/2\hbar and Ex=7.071E_{x} = 7.071 MeV. In addition to the observation of highly-fragmented level scheme belonging to the positive-parity sequences at Ex_{x}\sim 5 MeV, the termination of a negative-parity sequence connected by E2E2 transitions has been established at J=47/2J = 47/2 \hbar and Ex=11.877E_{x} = 11.877 MeV. The experimental results corresponding to both the positive- and negative-parity sequences have been theoretically interpreted in the framework of the core particle coupling model. Evidence is presented for a shape change from collective prolate to non-collective oblate above the Jπ=39/2J^{\pi} = 39/2^{-} (8011 keV) level and for a smooth termination of the negative-parity band.Comment: 19 pages, 8 figures. Submitted to Phys. Rev.

    Coherence resonance in an unijunction transistor relaxation oscillator

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    The phenomenon of coherence resonance (CR) is investigated in an unijunction transistor relaxation oscillator (UJT-RO) and quantified by estimating the normal variance (NV). Depending upon the measuring points two types of NV curves have been obtained. We have observed that the degradations in coherency at higher noise amplitudes in our system is probably the result of direct interference of coherent oscillations and the stochastic perturbation. Degradation of coherency may be minimal if this direct interference of noise and coherent oscillations is eliminated.Comment: 4 pages, Coherence resonace, Uni junction relaxation oscillato

    Cornwall-Jackiw-Tomboulis effective potential for canonical noncommutative field theories

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    We apply the Cornwall-Jackiw-Tomboulis (CJT) formalism to the scalar λϕ4\lambda \phi^{4} theory in canonical-noncommutative spacetime. We construct the CJT effective potential and the gap equation for general values of the noncommutative parameter θμν\theta_{\mu\nu}. We observe that under the hypothesis of translational invariance, which is assumed in the effective potential construction, differently from the commutative case (θμν=0\theta_{\mu\nu}= 0), the renormalizability of the gap equation is incompatible with the renormalizability of the effective potential. We argue that our result, is consistent with previous studies suggesting that a uniform ordered phase would be inconsistent with the infrared structure of canonical noncommutative theories.Comment: 15 pages, LaTe

    High-spin structure and Band Termination in 103^{103}Cd

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    Excited states of the neutron deficient 103^{103}Cd nucleus have been investigated via the 72^{72}Ge(35^{35}Cl, p3n) reaction at beam energy of 135 MeV by use of in-beam spectroscopic methods. Gamma rays depopulating the excited states were detected using the Gammasphere spectrometer with high-fold γ\gamma-ray coincidences. A quadrupole γ\gamma-ray coincidence analysis (γ4\gamma^{4}) has been used to extend the known level scheme. The positive parity levels have been established up to J=35/2J = 35/2\hbar and Ex=7.071E_{x} = 7.071 MeV. In addition to the observation of highly-fragmented level scheme belonging to the positive-parity sequences at Ex_{x}\sim 5 MeV, the termination of a negative-parity sequence connected by E2E2 transitions has been established at J=47/2J = 47/2 \hbar and Ex=11.877E_{x} = 11.877 MeV. The experimental results corresponding to both the positive- and negative-parity sequences have been theoretically interpreted in the framework of the core particle coupling model. Evidence is presented for a shape change from collective prolate to non-collective oblate above the Jπ=39/2J^{\pi} = 39/2^{-} (8011 keV) level and for a smooth termination of the negative-parity band.Comment: 19 pages, 8 figures. Submitted to Phys. Rev.

    CMAC Trained Optimum Mid course Guidance for Tactical Flight Vehicle

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    This paper discusses design and validation of neural network based mid-course guidance law of a surface to air flight vehicle. In present study, initially different optimal trajectories have been generated off-line of different pursuer-evader engagements by ensuring minimum flight time, maximum terminal velocity and favorable handing over conditions for seeker based terminal guidance. These optimal trajectories have been evolved by nonlinear programming based direct method of optimisation. The kinematic information of both pursuer and evader, generated based on these trajectories have been used to train cerebellar model articulate controller (CMAC) neural network. Later for a given engagement scenario an on-line near optimal mid-course guidance law has been evolved based on output of trained network. Training has been carried out by CMAC type supervisory neural network. The tested engagement condition is within input/output training space of neural network. Seeker based homing guidance has been used for terminal phase. Complete methodology has been validated along pitch plane of pursuer-evader engagement. During mid-course phase, the guidance demand has been tracked by attitude hold autopilot and during terminal phase, the guidance demanded lateral acceleration has been tracked by acceleration autopilot. System robustness has been studied in presence of plant parameter variations and sensor noise under Monte Carlo Platform
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