25,510 research outputs found
Compact and High Performance Dual-band Bandpass Filter Using Resonator-embedded Scheme for WLANs
A compact microstrip dual-band bandpass filter (DBBPF) with high selectivity and good suppression for wireless local area networks (WLANs) is proposed utilizing a novel embedded scheme resonator. Two passbands are produced by a pair of embedded half-wavelength meandered stepped-impedance resonator (MSIR) and a quadwavelength short stub loaded stepped-impedance resonator (SIR) separately. The resonator is fed by folded Tshaped capacitive source-load coupling microstrip feed line, and four transmission zeros are obtained at both sides of the bands to improve selectivity and suppression. Simultaneously, the size of the filter is extermely compact because embedding half-wavelength MSIR only changes the interior configuration of quad-wavelength SIR. To validate the design method, the designed filter is fabricated and measured. Both simulated and measured results indicate that good transmission property has been achieved
Statistical Topography of Glassy Interfaces
Statistical topography of two-dimensional interfaces in the presence of
quenched disorder is studied utilizing combinatorial optimization algorithms.
Finite-size scaling is used to measure geometrical exponents associated with
contour loops and fully packed loops. We find that contour-loop exponents
depend on the type of disorder (periodic ``vs'' non-periodic) and they satisfy
scaling relations characteristic of self-affine rough surfaces. Fully packed
loops on the other hand are unaffected by disorder with geometrical exponents
that take on their pure values.Comment: 4 pages, REVTEX, 4 figures included. Further information can be
obtained from [email protected]
Quantum asymmetric cryptography with symmetric keys
Based on quantum encryption, we present a new idea for quantum public-key
cryptography (QPKC) and construct a whole theoretical framework of a QPKC
system. We show that the quantum-mechanical nature renders it feasible and
reasonable to use symmetric keys in such a scheme, which is quite different
from that in conventional public-key cryptography. The security of our scheme
is analyzed and some features are discussed. Furthermore, the state-estimation
attack to a prior QPKC scheme is demonstrated.Comment: 8 pages, 1 figure, Revtex
Semileptonic Decays to and in Bethe-Salpeter Method
Using the relativistic Bethe-Salpeter method, the electron energy spectrum
and the semileptonic decay widths of and
are calculated. We obtained large branching
ratios, and , which can be easily detected in the future
experiment.Comment: 3 pages, 3 figures
B\"{a}cklund transformations for high-order constrained flows of the AKNS hierarchy: canonicity and spectrality property
New infinite number of one- and two-point B\"{a}cklund transformations (BTs)
with explicit expressions are constructed for the high-order constrained flows
of the AKNS hierarchy. It is shown that these BTs are canonical transformations
including B\"{a}cklund parameter and a spectrality property holds with
respect to and the 'conjugated' variable for which the point
belongs to the spectral curve. Also the formulas of m-times
repeated Darboux transformations for the high-order constrained flows of the
AKNS hierarchy are presented.Comment: 21 pages, Latex, to be published in J. Phys.
Intrinsic Percolative Superconductivity in KxFe2-ySe2 Single Crystals
Magnetic field penetration and magnetization hysteresis loops (MHLs) have
been measured in KxFe2-ySe2 single crystals. The magnetic field penetration
shows a two-step feature with a very small full-magnetic-penetration field
(Hp1= 300 Oe at 2 K), and accordingly the MHL exhibits an abnormal vanishing of
the central peak near zero field below 13 K. The width of the MHL in KxFe2-ySe2
at the same temperature is in general much smaller than that measured in the
relatives Ba0.6K0.4Fe2As2 and Ba(Fe0.92Co0.08)2As2, and the MHLs in the latter
two samples show the normal central peak near zero field. All these anomalies
found in KxFe2-ySe2 can be understood in the picture that the sample is
percolative with weakly coupled superconducting islands.Comment: 5 page, 4 figure
Empirical study in assessment of safety climate in construction site
With the rate of safety accidents during the
engineering construction becoming higher and higher,
more and more attention was paid on engineering safety.
To better cognize the present safety situation of engineering
construction without which prevention are hard to develop,
this paper developed 2 surveys which aims at evaluating
the present safety situation of a series of construction
dominated by urban construction bureau of Dong’guan
city in Guangdong province. Based on so many existing
papers, safety climate is the most important impaction of
safety accidents, furthermore, safety altitude reflect safety
climate to a great extent, thus the first survey is developed
to testify the conclusion. Based on the conclusion, another
survey is developed to evaluate safety situation in
Dong’guan city
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