Tight Coupling Dual-Band Coupler With Large Frequency Ratio and Arbitrary Power Division Ratios Over Two Bands

To satisfy the requirements of the emerging wireless communication system, the simultaneous implementation of large frequency ratio and tight coupling is demanded for a dual-band coupler. But most of the existing dual-band coupler structures can only achieve one of them. In this paper, a new coupled line based dual-band coupler structure is proposed. The detailed theoretical analysis is conducted for different ranges of frequency ratio. It was shown that a wide frequency ratio from 1.4 to 11.7 can be achieved even for the designs which require a tight coupling of 3 dB. For higher flexibility, the same circuit topology is further investigated to implement the arbitrary power division ratios over the two bands. More importantly, the design parameters for the large frequency ratio and arbitrary power division ratio are found to be almost independent resulting in a simple design procedure. For demonstration purposes, a dual-band 3 dB coupler with a large frequency ratio of 6 is designed, fabricated and measured. Furthermore, another dual-band coupler with coupling coefficients of 3 dB and 6 dB at 2 GHz and 4 GHz is designed, fabricated and measured. Good agreement between simulation and measurement can be observed for both prototypes.11Ysciescopu

Auxiliary potential in no-core shell-model calculations

The Lee-Suzuki iteration method is used to include the folded diagrams in the calculation of the two-body effective interaction $v^{(2)}_{\rm eff}$ between two nucleons in a no-core model space. This effective interaction still depends upon the choice of single-particle basis utilized in the shell-model calculation. Using a harmonic-oscillator single-particle basis and the Reid-soft-core {\it NN} potential, we find that $v^{(2)}_{\rm eff}$ overbinds ^4\mbox{He} in 0, 2, and $4\hbar\Omega$ model spaces. As the size of the model space increases, the amount of overbinding decreases significantly. This problem of overbinding in small model spaces is due to neglecting effective three- and four-body forces. Contributions of effective many-body forces are suppressed by using the Brueckner-Hartree-Fock single-particle Hamiltonian.Comment: 14 text pages and 4 figures (in postscript, available upon request). AZ-PH-TH/94-2

Nuclear shell-model calculations for 6Li and 14N with different NN potentials

Two ``phase-shift equivalent'' local NN potentials with different parametrizations, Reid93 and NijmII, which were found to give nearly identical results for the triton by Friar et al, are shown to yield remarkably similar results for 6Li and 14N in a (0+2)hw no-core space shell-model calculation. The results are compared with those for the widely used Hamada-Johnson hard-core and the original Reid soft-core potentials, which have larger deuteron D-state percentages. The strong correlation between the tensor strength and the nuclear binding energy is confirmed. However, many nuclear-structure properties seem to be rather insensitive to the details of the NN potential and, therefore, cannot be used to test various NN potentials. (Submitted to Phys. Rev. C on Nov. 9, 1993 as a Brief Report.)Comment: 12 text pages and 1 figure (Figure available upon request), University of Arizona Physics Preprint (Number not yet assigned

Simple approximation for the starting-energy-independent two-body effective interaction with applications to 6Li

We apply the Lee-Suzuki iteration method to calculate the linked-folded diagram series for a new Nijmegen local NN potential. We obtain an exact starting-energy-independent effective two-body interaction for a multi-shell, no-core, harmonic-oscillator model space. It is found that the resulting effective-interaction matrix elements can be well approximated by the Brueckner G-matrix elements evaluated at starting energies selected in a simple way. These starting energies are closely related to the energies of the initial two-particle states in the ladder diagrams. The ``exact'' and approximate effective interactions are used to calculate the energy spectrum of 6Li in order to test the utility of the approximate form.Comment: 15 text pages and 2 PostScript figures (available upon request). University of Arizona preprint, Number unassigne

Elementary operations for quantum logic with a single trapped two-level cold ion beyond Lamb-Dicke limit

A simple alternative scheme for implementing quantum gates with a single trapped cold two-level ion beyond the Lamb-Dicke (LD) limit is proposed. Basing on the quantum dynamics for the laser-ion interaction described by a generalized Jaynes-Cummings model, one can introduce two kinds of elementary quantum operations i.e., the simple rotation on the bare atomic state, generated by applying a resonant pulse, and the joint operation on the internal and external degrees of the ion, performed by using an off-resonant pulse. Several typical quantum gates, including Hadamard gate, controlled-Z and controlled-NOT gates $etc.$, can thus be implemented exactly by using these elementary operations. The experimental parameters including the LD parameter and the durations of the applied laser pulses, for these implementation are derived analytically and numerically. Neither the LD approximation for the laser-ion interaction nor the auxiliary atomic level is needed in the present scheme.Comment: 5 pages, no figure, to appear in Opt. Com

Pyrene Mineralization by Mycobacterium sp. Strain KMS in a Barley Rhizosphere

To determine whether the soil Mycobacterium isolate KMS would mineralize pyrene under rhizosphere conditions, a microcosm system was established to collect radioactive carbon dioxide released from the labeled polycyclic aromatic hydrocarbon. Microcosms were designed as sealed, flow-through systems that allowed the growth of plants. Experiments were conducted to evaluate mineralization of 14C-labeled pyrene in a sand amended with the polycyclic aromatic hydrocarbons degrading Mycobacterium isolate KMS, barley plants, or barley plants with roots colonized by isolate KMS. Mineralization was quantified by collecting the 14CO2 produced from 14C-labeled pyrene at intervals during the 10-d incubation period. Roots and foliar tissues were examined for 14C incorporation. Mass balances for microcosms were determined through combustion of sand samples and collection and quantification of 14CO2 evolved from radiolabeled pyrene. No pyrene mineralization was observed in the sterile control systems. Greater release of 14CO2 was observed in the system with barley colonized by KMS than in microcosms containing just the bacterium inoculum or sterile barley plants. These findings suggest that phytostimulation of polycyclic aromatic hydrocarbons mineralization could be applied in remediation schemes

In-Plane Magnetic Anisotropy In RF Sputtered Fe-N Thin Films

We have fabricated Fe(N) thin films with varied N2 partial pressure and studied the microstructure, morphology, magnetic properties and resistivity by using X-ray diffraction, atomic force microscopy, transmission electron microscopy, vibrating-sample magnetometer and angle-resolved M-H hysteresis Loop tracer and standard four-point probe method. In the presence of low N2 partial pressure, Fe(N) films showed a basic bcc a-Fe structure with a preferred (110) texture. A variation of in-plane magnetic anisotropy of the Fe(N) films was observed with the changing of N component. The evolution of in-plane anisotropy in the films was attributed to the directional order mechanism. Nitrogen atoms play an important role in refining the a-Fe grains and inducing uniaxial anisotropy.Comment: 11 pages, 6 figure

Distributed phase-covariant cloning with atomic ensembles via quantum Zeno dynamics

We propose an interesting scheme for distributed orbital state quantum cloning with atomic ensembles based on the quantum Zeno dynamics. These atomic ensembles which consist of identical three-level atoms are trapped in distant cavities connected by a single-mode integrated optical star coupler. These qubits can be manipulated through appropriate modulation of the coupling constants between atomic ensemble and classical field, and the cavity decay can be largely suppressed as the number of atoms in the ensemble qubits increases. The fidelity of each cloned qubit can be obtained with analytic result. The present scheme provides a new way to construct the quantum communication network.Comment: 5 pages, 4 figure

Large-space shell-model calculations for light nuclei

An effective two-body interaction is constructed from a new Reid-like $NN$ potential for a large no-core space consisting of six major shells and is used to generate the shell-model properties for light nuclei from $A$=2 to 6. (For practical reasons, the model space is partially truncated for $A$=6.) Binding energies and other physical observables are calculated and compare favorably with experiment.Comment: prepared using LaTex, 21 manuscript pages, no figure

Approximate Particle Number Projection for Rotating Nuclei

Pairing correlations in rotating nuclei are discussed within the Lipkin-Nogami method. The accuracy of the method is tested for the Krumlinde-Szyma\'nski R(5) model. The results of calculations are compared with those obtained from the standard mean field theory and particle-number projection method, and with exact solutions.Comment: 15 pages, 6 figures available on request, REVTEX3.