217 research outputs found
Moving Target Simulation of Multi-Band Radar Based on Doppler Frequency Signal Generation Technology
This paper proposes a corner reflector and Luneburg ball reflector group. The omnidirectional radar cross-sectional (RCS) distribution characteristics of a fighter are simulated using the sharp and smooth RCS distribution features of the corner and the Luneburg ball reflectors, respectively. A new type of Doppler signal generation principle is proposed to design a Doppler frequency simulator to transmit frequency signals by connecting in parallel with the metal layer of the corner reflector and the Luneburg sphere ball, and then transmit through their other end. The existing radar target aircraft cannot simulate the RCS and speed of the targets that are less than 0.005 m2 by enhancing the echo intensity of the target location, which makes it impossible for the military to conduct practice drills and evaluate the effectiveness of the air defense systems. The experimental results show that the Doppler frequency simulator successfully simulates the target speed of 0-80 km/h and when the speed is greater than 20 km/h, the error of the simulation frequency is less than 1.5%. The proposed method can provide guidance and a theoretical basis for simulating the speed of various types of aircraft in future work
Revisiting the B {\to} {\pi} {\rho}, {\pi} {\omega} Decays in the Perturbative QCD Approach Beyond the Leading Order
We calculate the branching ratios and CP asymmetries of the ,
decays in the perturbative QCD factorization approach up to the
next-to-leading-order contributions. We find that the next-to-leading-order
contributions can interfere with the leading-order part constructively or
destructively for different decay modes. Our numerical results have a much
better agreement with current available data than previous leading-order
calculations, e.g., the next-to-leading-order corrections enhance the
branching ratios by a factor 2.5, which is helpful
to narrow the gaps between theoretic predictions and experimental data. We also
update the direct CP-violation parameters, the mixing-induced CP-violation
parameters of these modes, which show a better agreement with experimental data
than many of the other approaches.Comment: 23 pages, 4 figures, 4 table
Silk Fibroin Nanoparticles: A Biocompatible Multi-Functional Polymer for Drug Delivery
The versatility of nanomedicines allows for various modifications of material type, size, charge and functionalization, offering a promising platform for biomedical applications including tumor targeting. One such material, silk fibroin (SF) has emerged, displaying an excellent combination of mechanical and biological properties characterized by its high tensile and breaking strength, elongation, stiffness and ductility. High stability allows SF to maintain its chemical structure even at high temperatures (around 250°C) and compared with other biological polymers like polylactide (PLA), poly(lactic-co-glycolic acid) (PLGA), and collagen, SF shows excellent biocompatibility and lower immunogenic response making it a very suitable material for drug delivery and tissue engineering. Here we describe the structure, synthesis and properties of SF nanoparticles. We evaluate its emergence as a multi-functional polymer for its utility as a nanocarrier to deliver cancer therapies directly to tumors together with considerations for its clinical use
Loop effects and non-decoupling property of SUSY QCD in
One-loop SUSY QCD radiative correction to cross section is
calculated in the Minimal Supersymmetric Standard Model. We found that SUSY QCD
is non-decoupling if the gluino mass and the parameter , or
are at the same order and get large. The non-decoupling contribution can be
enhanced by large and therefore large corrections to the hadronic
production rates at the Tevatron and LHC are expected in the large
limit. The fundamental reason for such non-decoupling behavior is found to be
some couplings in the loops being proportional to SUSY mass parameters.Comment: 15 pages, 5 PS figures. A proof of non-decouplings of SUSY-QCD,
Comments on corresponding QCD correction and references adde
Higgs-boson production associated with a bottom quark at hadron colliders with SUSY-QCD corrections
The Higgs boson production p p (p\bar p) -> b h +X via b g -> b h at the LHC,
which may be an important channel for testing the bottom quark Yukawa coupling,
is subject to large supersymmetric quantum corrections. In this work the
one-loop SUSY-QCD corrections to this process are evaluated and are found to be
quite sizable in some parameter space. We also study the behavior of the
corrections in the limit of heavy SUSY masses and find the remnant effects of
SUSY-QCD. These remnant effects, which are left over in the Higgs sector by the
heavy sparticles, are found to be so sizable (for a light CP-odd Higgs and
large \tan\beta) that they might be observable in the future LHC experiment.
The exploration of such remnant effects is important for probing SUSY,
especially in case that the sparticles are too heavy (above TeV) to be directly
discovered at the LHC.Comment: Results for the Tevatron adde
Study of the B^0 Semileptonic Decay Spectrum at the Upsilon(4S) Resonance
We have made a first measurement of the lepton momentum spectrum in a sample
of events enriched in neutral B's through a partial reconstruction of B0 -->
D*- l+ nu. This spectrum, measured with 2.38 fb**-1 of data collected at the
Upsilon(4S) resonance by the CLEO II detector, is compared directly to the
inclusive lepton spectrum from all Upsilon(4S) events in the same data set.
These two spectra are consistent with having the same shape above 1.5 GeV/c.
From the two spectra and two other CLEO measurements, we obtain the B0 and B+
semileptonic branching fractions, b0 and b+, their ratio, and the production
ratio f+-/f00 of B+ and B0 pairs at the Upsilon(4S). We report b+/b0=0.950
(+0.117-0.080) +- 0.091, b0 = (10.78 +- 0.60 +- 0.69)%, and b+ = (10.25 +- 0.57
+- 0.65)%. b+/b0 is equivalent to the ratio of charged to neutral B lifetimes,
tau+/tau0.Comment: 14 page, postscript file also available at
http://w4.lns.cornell.edu/public/CLN
Measurement of the branching fraction for
We have studied the leptonic decay of the resonance into tau
pairs using the CLEO II detector. A clean sample of tau pair events is
identified via events containing two charged particles where exactly one of the
particles is an identified electron. We find . The result is consistent with
expectations from lepton universality.Comment: 9 pages, RevTeX, two Postscript figures available upon request, CLNS
94/1297, CLEO 94-20 (submitted to Physics Letters B
Measurement of the Decay Asymmetry Parameters in and
We have measured the weak decay asymmetry parameters (\aLC ) for two \LC\
decay modes. Our measurements are \aLC = -0.94^{+0.21+0.12}_{-0.06-0.06} for
the decay mode and \aLC = -0.45\pm 0.31 \pm
0.06 for the decay mode . By combining these
measurements with the previously measured decay rates, we have extracted the
parity-violating and parity-conserving amplitudes. These amplitudes are used to
test models of nonleptonic charmed baryon decay.Comment: 11 pages including the figures. Uses REVTEX and psfig macros. Figures
as uuencoded postscript. Also available as
http://w4.lns.cornell.edu/public/CLNS/1995/CLNS95-1319.p
Observation of the Charmed Baryon Decays to , , and
We have observed two new decay modes of the charmed baryon into
and using data collected with the
CLEO II detector. We also present the first measurement of the branching
fraction for the previously observed decay mode . The branching fractions for these three modes relative to
are measured to be , , and , respectively.Comment: 12 page uuencoded postscript file, postscript file also available
through http://w4.lns.cornell.edu/public/CLN
Search for CP Violation in D^0--> K_S^0 pi^+pi^-
We report on a search for CP violation in the decay of D0 and D0B to Kshort
pi+pi-. The data come from an integrated luminosity of 9.0 1/fb of e+e-
collisions at sqrt(s) ~ 10 GeV recorded with the CLEO II.V detector. The
resonance substructure of this decay is well described by ten quasi-two-body
decay channels (K*-pi+, K*0(1430)-pi+, K*2(1430)-pi+, K*(1680)-pi+, Kshort rho,
Kshort omega, Kshort f0(980), Kshort f2(1270), Kshort f0(1370), and the ``wrong
sign'' K*+ pi-) plus a small non-resonant component. We observe no evidence for
CP violation in the amplitudes and phases that describe the decay D0 to K_S^0
pi+pi-.Comment: 10 pages, 3 figures, also available at
http://w4.lns.cornell.edu/public/CLNS/, submitted to PR
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