29,095 research outputs found

    Measurement and Calibration of A High-Sensitivity Microwave Power Sensor with An Attenuator

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    In this paper, measurement and calibration of a high-sensitivity microwave power sensor through an attenuator is performed using direct comparison transfer technique. To provide reliable results, a mathematical model previously derived using signal flow graphs together with non-touching loop rule analysis for the measurement estimate (i.e. calibration factor) and its uncertainty evaluation is comparatively investigated. The investigation is carried out through the analysis of physical measurement processes, and consistent mathematical model is observed. Later, an example of Type-N (up to 18 GHz) application is used to demonstrate its calibration and measurement capability

    Doublet bands in 126^{126}Cs in the triaxial rotor model coupled with two quasiparticles

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    The positive parity doublet bands based on the πh11/2νh11/2\pi h_{11/2}\otimes\nu h_{11/2} configuration in 126^{126}Cs have been investigated in the two quasi-particles coupled with a triaxial rotor model. The energy spectra E(I)E(I), energy staggering parameter S(I)=[E(I)E(I1)]/2IS(I)=[E(I)-E(I-1)]/2I, B(M1)B(M1) and B(E2)B(E2) values, intraband B(M1)/B(E2)B(M1)/B(E2) ratios, B(M1)in/B(M1)outB(M1)_{\textrm{in}}/B(M1)_{\textrm{out}} ratios, and orientation of the angular momentum for the rotor as well as the valence proton and neutron are calculated. After including the pairing correlation, good agreement has been obtained between the calculated results and the data available, which supports the interpretation of this positive parity doublet bands as chiral bands.Comment: Phys.Rev.C (accepted

    Chiral bands for quasi-proton and quasi-neutron coupling with a triaxial rotor

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    A particle rotor model (PRM) with a quasi-proton and a quasi-neutron coupled with a triaxial rotor is developed and applied to study chiral doublet bands with configurations of a h11/2h_{11/2} proton and a h11/2h_{11/2} quasi-neutron. With pairing treated by the BCS approximation, the present quasi-particle PRM is aimed at simulating one proton and many neutron holes coupled with a triaxial rotor. After a detailed analysis of the angular momentum orientations, energy separation between the partner bands, and behavior of electromagnetic transitions, for the first time we find aplanar rotation or equivalently chiral geometry beyond the usual one proton and one neutron hole coupled with a triaxial rotor.Comment: 25 pages, 10 figures, accepted for publication in Physical Review

    The effect of asymmetry of the coil block on self-assembly in ABC coil-rod-coil triblock copolymers

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    Using the self-consistent field approach, the effect of asymmetry of the coil block on the microphase separation is focused in ABC coil-rod-coil triblock copolymers. For different fractions of the rod block fBf_{\text B}, some stable structures are observed, i.e., lamellae, cylinders, gyroid, and core-shell hexagonal lattice, and the phase diagrams are constructed. The calculated results show that the effect of the coil block fraction fAf_{\text A} is dependent on fBf_{\text B}. When fB=0.2f_{\text B}=0.2, the effect of asymmetry of the coil block is similar to that of the ABC flexible triblock copolymers; When fB=0.4f_{\text B}=0.4, the self-assembly of ABC coil-rod-coil triblock copolymers behaves like rod-coil diblock copolymers under some condition. When fBf_{\text B} continues to increase, the effect of asymmetry of the coil block reduces. For fB=0.4f_{\text B}=0.4, under the symmetrical and rather asymmetrical conditions, an increase in the interaction parameter between different components leads to different transitions between cylinders and lamellae. The results indicate some remarkable effect of the chain architecture on self-assembly, and can provide the guidance for the design and synthesis of copolymer materials.Comment: 9 pages, 3 figure

    Mean-field embedding of the dual fermion approach for correlated electron systems

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    To reduce the rapidly growing computational cost of the dual fermion lattice calculation with increasing system size, we introduce two embedding schemes. One is the real fermion embedding, and the other is the dual fermion embedding. Our numerical tests show that the real fermion and dual fermion embedding approaches converge to essentially the same result. The application on the Anderson disorder and Hubbard models shows that these embedding algorithms converge more quickly with system size as compared to the conventional dual fermion method, for the calculation of both single-particle and two-particle quantities.Comment: 10 pages, 10 figure
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