15,352 research outputs found
Novel Compact and High Selectivity Dual-band BPF with Wide Stopband
A novel type of compact and high selectivity dual-band bandpass filter (BPF) incorporating a dual-mode defected ground structure resonator (DDGSR) and a dual-mode open-stub loaded stepped impedance resonator (DOLSIR) is proposed in this paper. Utilizing capacitive source-load coupling and the intrinsic characteristics of the two types of dual-mode resonators, compact dual-band BPF with multi transmission zeros near the passband edges as well as a wide stopband which can be used to achieve high selectivity is realized. An experimental dual-band BPF located at 2.4 and 3.2 GHz was designed and fabricated. The validity of the design approach is verified by good agreement between simulated and measurement results
Two problems related to prescribed curvature measures
Existence of convex body with prescribed generalized curvature measures is
discussed, this result is obtained by making use of Guan-Li-Li's innovative
techniques. In surprise, that methods has also brought us to promote
Ivochkina's estimates for prescribed curvature equation in \cite{I1, I}.Comment: 12 pages, Corrected typo
Thermal-magnetic noise measurement of spin-torque effects on ferromagnetic resonance in MgO-based magnetic tunnel junctions
Thermal-magnetic noise at ferromagnetic resonance (T-FMR) can be used to
measure magnetic perpendicular anisotropy of nanoscale magnetic tunnel
junctions (MTJs). For this purpose, T-FMR measurements were conducted with an
external magnetic field up to 14 kOe applied perpendicular to the film surface
of MgO-based MTJs under a dc bias. The observed frequency-field relationship
suggests that a 20 A CoFeB free layer has an effective demagnetization field
much smaller than the intrinsic bulk value of CoFeB, with 4PiMeff = (6.1 +/-
0.3) kOe. This value is consistent with the saturation field obtained from
magnetometry measurements on extended films of the same CoFeB thickness.
In-plane T-FMR on the other hand shows less consistent results for the
effective demagnetization field, presumably due to excitations of more complex
modes. These experiments suggest that the perpendicular T-FMR is preferred for
quantitative magnetic characterization of nanoscale MTJs.Comment: 10 pages, 3 figures, accepted by AP
KDM2B/FBXL10 targets c-Fos for ubiquitylation and degradation in response to mitogenic stimulation.
KDM2B (also known as FBXL10) controls stem cell self-renewal, somatic cell reprogramming and senescence, and tumorigenesis. KDM2B contains multiple functional domains, including a JmjC domain that catalyzes H3K36 demethylation and a CxxC zinc-finger that recognizes CpG islands and recruits the polycomb repressive complex 1. Here, we report that KDM2B, via its F-box domain, functions as a subunit of the CUL1-RING ubiquitin ligase (CRL1/SCF(KDM2B)) complex. KDM2B targets c-Fos for polyubiquitylation and regulates c-Fos protein levels. Unlike the phosphorylation of other SCF (SKP1-CUL1-F-box)/CRL1 substrates that promotes substrates binding to F-box, epidermal growth factor (EGF)-induced c-Fos S374 phosphorylation dissociates c-Fos from KDM2B and stabilizes c-Fos protein. Non-phosphorylatable and phosphomimetic mutations at S374 result in c-Fos protein which cannot be induced by EGF or accumulates constitutively and lead to decreased or increased cell proliferation, respectively. Multiple tumor-derived KDM2B mutations impaired the function of KDM2B to target c-Fos degradation and to suppress cell proliferation. These results reveal a novel function of KDM2B in the negative regulation of cell proliferation by assembling an E3 ligase to targeting c-Fos protein degradation that is antagonized by mitogenic stimulations
The algebraic Bethe ansatz for open vertex models
We present a unified algebraic Bethe ansatz for open vertex models which are
associated with the non-exceptional
Lie algebras.
By the method, we solve these models with the trivial K matrix and find that
our results agree with that obtained by analytical
Bethe ansatz. We also solve the models with
some non-trivial diagonal K-matrices (one free parameter case) by the algebraic
Bethe ansatz.Comment: Latex, 35 pages, new content and references are added, minor
revisions are mad
Thermodynamics, spin-charge separation and correlation functions of spin-1/2 fermions with repulsive interaction
We investigate the low temperature thermodynamics and correlation functions
of one-dimensional spin-1/2 fermions with strong repulsion in an external
magnetic field via the thermodynamic Bethe ansatz method. The exact
thermodynamics of the model in a weak magnetic field is derived with the help
of Wiener-Hopf techniques. It turns out that the low energy physics can be
described by spin-charge separated conformal field theories of an effective
Tomonaga-Luttinger liquid and an antiferromagnetic SU(2) Heisenberg spin chain.
However, these two types of conformally invariant low-lying excitations may
break down as excitations take place far away from the Fermi points. The long
distance asymptotics of the correlation functions and the critical exponents
for the model in the presence of a magnetic field at zero temperature are
derived in detail by solving dressed charge equations and by conformal mapping.
Furthermore, we calculate the conformal dimensions for particular cases of
correlation functions. The leading terms of these correlation functions are
given explicitly for a weak magnetic field and for a magnetic field
close to the critical field . Our analytical results
provide insights into universal thermodynamics and criticality in
one-dimensional many-body physics.Comment: revised version, 47 pages, 4 figures, additional tex
Exploration and Research on the Mixed Mode Curriculum of “Competition, Training and Teaching”
In response to the many problems encountered in the teaching of the “SSM Framework” course, a project-driven hybrid teaching model is proposed. The reform integrates “Competition, Training and Teaching” into one, utilizes online teaching platforms to arrange pre-class activities, carry out interactive teaching in class, and improve post-class practice. In teaching, the roles of teachers and students should be exchanged to fully mobilize students’ learning initiative and cultivate their ability to solve and analyze problems. In the assessment, a process evaluation mechanism is introduced to incorporate project construction into the assessment scope and improve practical application capabilities. The practical results indicate that the application of the new model in curriculum significantly enhances students’ learning interest and practical abilities, which is feasible for promotion
First-principles study of the optoelectronic properties and photovoltaic absorber layer efficiency of Cu-based chalcogenides
Cu-based chalcogenides are promising materials for thin-film solar cells with
more than 20% measured cell efficiency. Using first-principles calculations
based on density functional theory, the optoelectronic properties of a group of
Cu-based chalcogenides Cu-II-IV-VI is studied. They are then screened
with the aim of identifying potential absorber materials for photovoltaic
applications. The spectroscopic limited maximum efficiency (SLME) introduced by
Yu and Zunger is used as a metric for the screening. After constructing the
current-voltage curve, the maximum spectroscopy dependent power conversion
efficiency is calculated from the maximum power output. The role of the nature
of the band gap, direct or indirect, and also of the absorptivity of the
studied materials on the maximum theoretical power conversion efficiency is
studied. Our results show that Cu-II-GeSe with II=Cd and Hg, and
Cu-II-SnS with II=Cd and Zn have a higher theoretical efficiency
compared to the materials currently used as absorber layer
Integrable variant of the one-dimensional Hubbard model
A new integrable model which is a variant of the one-dimensional Hubbard
model is proposed. The integrability of the model is verified by presenting the
associated quantum R-matrix which satisfies the Yang-Baxter equation. We argue
that the new model possesses the SO(4) algebra symmetry, which contains a
representation of the -pairing SU(2) algebra and a spin SU(2) algebra.
Additionally, the algebraic Bethe ansatz is studied by means of the quantum
inverse scattering method. The spectrum of the Hamiltonian, eigenvectors, as
well as the Bethe ansatz equations, are discussed
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