19,421 research outputs found
Sampled-Data and Harmonic Balance Analyses of Average Current-Mode Controlled Buck Converter
Dynamics and stability of average current-mode control of buck converters are
analyzed by sampled-data and harmonic balance analyses. An exact sampled-data
model is derived. A new continuous-time model "lifted" from the sampled-data
model is also derived, and has frequency response matched with experimental
data reported previously. Orbital stability is studied and it is found
unrelated to the ripple size of the current-loop compensator output. An
unstable window of the current-loop compensator pole is found by simulations,
and it can be accurately predicted by sampled-data and harmonic balance
analyses. A new S plot accurately predicting the subharmonic oscillation is
proposed. The S plot assists pole assignment and shows the required ramp slope
to avoid instability.Comment: Submitted to International Journal of Circuit Theory and Applications
on August 9, 2011; Manuscript ID: CTA-11-016
Controllable Goos-H\"{a}nchen shifts and spin beam splitter for ballistic electrons in a parabolic quantum well under a uniform magnetic field
The quantum Goos-H\"{a}nchen shift for ballistic electrons is investigated in
a parabolic potential well under a uniform vertical magnetic field. It is found
that the Goos-H\"{a}nchen shift can be negative as well as positive, and
becomes zero at transmission resonances. The beam shift depends not only on the
incident energy and incidence angle, but also on the magnetic field and Landau
quantum number. Based on these phenomena, we propose an alternative way to
realize the spin beam splitter in the proposed spintronic device, which can
completely separate spin-up and spin-down electron beams by negative and
positive Goos-H\"{a}nchen shifts.Comment: 6 pages, 6 figure
Renewable Composite Quantile Method and Algorithm for Nonparametric Models with Streaming Data
We are interested in renewable estimations and algorithms for nonparametric
models with streaming data. In our method, the nonparametric function of
interest is expressed through a functional depending on a weight function and a
conditional distribution function (CDF). The CDF is estimated by renewable
kernel estimations combined with function interpolations, based on which we
propose the method of renewable weighted composite quantile regression (WCQR).
Then we fully use the model structure and obtain new selectors for the weight
function, such that the WCQR can achieve asymptotic unbiasness when estimating
specific functions in the model. We also propose practical bandwidth selectors
for streaming data and find the optimal weight function minimizing the
asymptotic variance. The asymptotical results show that our estimator is almost
equivalent to the oracle estimator obtained from the entire data together.
Besides, our method also enjoys adaptiveness to error distributions, robustness
to outliers, and efficiency in both estimation and computation. Simulation
studies and real data analyses further confirm our theoretical findings.Comment: 24 pages, 0 figure
2-Ethyl-5-nitroaniline
The molecule of the title compound, C8H10N2O2, is nearly planar [maximum deviation of 0.163 (3) Å for one of the O atoms of the NO2 group]. In the crystal structure, weak intermolecular N—H⋯N and C—H⋯O hydrogen bonds link the molecules into chains, forming R
2
2(10) ring motifs
Expanding CRISPR/Cas9 Genome Editing Capacity in Zebrafish Using SaCas9.
The type II CRISPR/Cas9 system has been used widely for genome editing in zebrafish. However, the requirement for the 5'-NGG-3' protospacer-adjacent motif (PAM) of Cas9 from Streptococcus pyogenes (SpCas9) limits its targeting sequences. Here, we report that a Cas9 ortholog from Staphylococcus aureus (SaCas9), and its KKH variant, successfully induced targeted mutagenesis with high frequency in zebrafish. Confirming previous findings, the SpCas9 variant, VQR, can also induce targeted mutations in zebrafish. Bioinformatics analysis of these new Cas targets suggests that the number of available target sites in the zebrafish genome can be greatly expanded. Collectively, the expanded target repertoire of Cas9 in zebrafish should further facilitate the utility of this organism for genetic studies of vertebrate biology
Glueball Masses from Hamiltonian Lattice QCD
We calculate the masses of the , and glueballs from
QCD in 3+1 dimensions using an eigenvalue equation method for Hamiltonian
lattice QCD developed and described elsewhere by the authors. The mass ratios
become approximately constants in the coupling region ,
from which we estimate and
.Comment: 12 pages, Latex, figures to be sent upon reques
- …