6,220 research outputs found
Compact Circularly Polarized Patch Antenna Using a Composite Right/Left-Handed Transmission Line Unit-Cell
A compact circularly polarized (CP) patch antenna using a composite right/left-handed (CRLH) transmission line (TL) unit-cell is proposed. The CRLH TL unit-cell includes a complementary split ring resonator (CSRR) for shunt inductance and a gap loaded with a circular-shaped slot for series capacitance. The CSRR can decrease the TM10 mode resonance frequency, thus reducing the electrical size of the proposed antenna. In addition, the asymmetry of the CSRR brings about the TM01 mode, which can be combined with the TM10 mode by changing the slot radius. The combination of these two orthogonal modes with 90° phase shift makes the proposed antenna provide a CP property. The experimental results show that the proposed antenna has a wider axial ratio bandwidth and a smaller electrical size than the reported CP antennas. Moreover, the proposed antenna is designed without impedance transformer, 90° phase shift, dual feed and ground via
Mgb2 Nonlinear Properties Investigated under Localized High RF Magnetic Field Excitation
In order to increase the accelerating gradient of Superconducting Radio
Frequency (SRF) cavities, Magnesium Diboride (MgB2) opens up hope because of
its high transition temperature and potential for low surface resistance in the
high RF field regime. However, due to the presence of the small superconducting
gap in the {\pi} band, the nonlinear response of MgB2 is potentially quite
large compared to a single gap s-wave superconductor (SC) such as Nb.
Understanding the mechanisms of nonlinearity coming from the two-band structure
of MgB2, as well as extrinsic sources, is an urgent requirement. A localized
and strong RF magnetic field, created by a magnetic write head, is integrated
into our nonlinear-Meissner-effect scanning microwave microscope [1]. MgB2
films with thickness 50 nm, fabricated by a hybrid physical-chemical vapor
deposition technique on dielectric substrates, are measured at a fixed location
and show a strongly temperature-dependent third harmonic response. We propose
that at least two mechanisms are responsible for this nonlinear response, one
of which involves vortex nucleation and penetration into the film. [1] T. M.
Tai, X. X. Xi, C. G. Zhuang, D. I. Mircea, S. M. Anlage, "Nonlinear Near-Field
Microwave Microscope for RF Defect Localization in Superconductors", IEEE
Trans. Appl. Supercond. 21, 2615 (2011).Comment: 6 pages, 6 figure
CP Violation in Fermion Pair Decays of Neutral Boson Particles
We study CP violation in fermion pair decays of neutral boson particles with
spin 0 or 1. We study a new asymmetry to measure CP violation in decays and discuss the possibility of measuring it
experimentally. For the spin-1 particles case, we study CP violation in the
decays of to octet baryon pairs. We show that these decays can
be used to put stringent constraints on the electric dipole moments of
, and .Comment: 14p, OZ-93/22, UM-93/89, OITS 51
Extraction of Principle Knowledge from Process Patents for Manufacturing Process Innovation
Process patents contain substantial knowledge of the principles behind manufacturing process problems-solving; however, this knowledge is implicit in lengthy texts and cannot be directly reused in innovation design. To effectively support systematic manufacturing process innovation, this paper presents an approach to extracting principle innovation knowledge from process patents. The proposed approach consists of (1) classifying process patents by taking process method, manufacturing object and manufacturing feature as the references; (2) extracting generalized process contradiction parameters and the principles behind solving such process contradictions based on patent mining and technology abstraction of TRIZ (the theory of inventive problem solving); and (3) constructing a domain process contradiction matrix and mapping the relationship between the matrix and the corresponding process patents. Finally, a case study is presented to illustrate the applicability of the proposed approach
Expression analysis of four flower-specific promoters of Brassica spp. in the heterogeneous host tobacco
The 5’-flanking region of ca. 1200 bp upstream of the translation start site (TSS) of a putative cell wall protein gene was cloned from Brassica campestris, B. chinensis, B. napus and B. oleracea, and transferred to tobacco via Agrobacterium-mediation after fused to promoter-less beta-glucuronidase(GUS) reporter gene. Histochemical GUS staining and fluorometric quantification of the transgenic tobacco showed that all four promoters conferred GUS expression in petal, anther, pollen and stigma ofthe flower, not in any vegetative organs or tissues of the plants. A series of 5’-end deletion of the promoter from B. napus disclosed that the region -104 to -17 relative to TSS was sufficient to confer flower-specific expression, and the region -181 to -161 played a key role in maintaining strong drivingpower of the promoter. Besides, several enhancer and suppressor regions were also identified in the promoter
Finite dimensional integrable Hamiltonian systems associated with DSI equation by Bargmann constraints
The Davey-Stewartson I equation is a typical integrable equation in 2+1
dimensions. Its Lax system being essentially in 1+1 dimensional form has been
found through nonlinearization from 2+1 dimensions to 1+1 dimensions. In the
present paper, this essentially 1+1 dimensional Lax system is further
nonlinearized into 1+0 dimensional Hamiltonian systems by taking the Bargmann
constraints. It is shown that the resulting 1+0 dimensional Hamiltonian systems
are completely integrable in Liouville sense by finding a full set of integrals
of motion and proving their functional independence.Comment: 10 pages, in LaTeX, to be published in J. Phys. Soc. Jpn. 70 (2001
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