1,961 research outputs found
Spinor field realizations of the non-critical string based on the linear algebra
In this paper, we investigate the spinor field realizations of the
algebra, making use of the fact that the algebra can be linearized
through the addition of a spin-1 current. And then the nilpotent BRST charges
of the spinor non-critical string were built with these realizations.Comment: 10 pages, no figures, revtex4 style, accepted by Commun.Theor.Phy
Gauge fields, ripples and wrinkles in graphene layers
We analyze elastic deformations of graphene sheets which lead to effective
gauge fields acting on the charge carriers. Corrugations in the substrate
induce stresses, which, in turn, can give rise to mechanical instabilities and
the formation of wrinkles. Similar effects may take place in suspended graphene
samples under tension.Comment: contribution to the special issue of Solid State Communications on
graphen
A REAL TIME MONITORING MODEL OF THE CALCIUM CARBONATE FOULING INDUCTION PERIOD BASED ON THE CONDUCTANCE TITRATION
A new method has been developed to monitor the calcium carbonate fouling induction period (CCFIP) in real time. Based on the conductance titration, this paper investigated the forming process of CCFIP by a staticdynamic combined simulation experiment unit. With the help of titration analysis (that is titrimetry), an accurate definition of CCFIP and the corresponding real time monitoring model were built up. The investigation results show that the proposed model applies not only to measure the CCFIP in real time, but also applies to an investigation of the influence of various factors on the CCFIP
Electronic states and optical properties of GaAs/AlAs and GaAs/vacuum superlattices by the linear combination of bulk bands method
The linear combination of bulk bands method recently introduced by Wang,
Franceschetti and Zunger [Phys. Rev. Lett.78, 2819 (1997)] is applied to a
calculation of energy bands and optical constants of (GaAs)/(AlAs) and
(GaAs)/(vacuum) (001) superlattices with n ranging from 4 to 20.
Empirical pseudopotentials are used for the calculation of the bulk energy
bands. Quantum-confined induced shifts of critical point energies are
calculated and are found to be larger for the GaAs/vacuum system. The
peak in the absorption spectra has a blue shift and splits into two peaks for
decreasing superlattice period; the transition instead is found to be
split for large-period GaAs/AlAs superlattices. The band contribution to linear
birefringence of GaAs/AlAs superlattices is calculated and compared with recent
experimental results of Sirenko et al. [Phys. Rev. B 60, 8253 (1999)]. The
frequency-dependent part reproduces the observed increase with decreasing
superlattice period, while the calculated zero-frequency birefringence does not
account for the experimental results and points to the importance of
local-field effects.Comment: 10 pages, 11 .eps figures, 1 tabl
Upconversion nanoparticle platform for efficient dendritic cell antigen delivery and simultaneous tracking
Upconversion nanoparticles (UCNPs) represent a group of NPs that can convert near-infrared (NIR) light into ultraviolet and visible light, thus possess deep tissue penetration power with less background fluorescence noise interference, and do not induce damage to biological tissues. Due to their unique optical properties and possibility for surface modification, UCNPs can be exploited for concomitant antigen delivery into dendritic cells (DCs) and monitoring by molecular imaging. In this study, we focus on the development of a nano-delivery platform targeting DCs for immunotherapy and simultaneous imaging. OVA 254–267 (OVA24) peptide antigen, harboring a CD8 T cell epitope, and Pam3CysSerLys4 (Pam3CSK4) adjuvant were chemically linked to the surface of UCNPs by amide condensation to stimulate DC maturation and antigen presentation. The OVA24-Pam3CSK4-UCNPs were thoroughly characterized and showed a homogeneous morphology and surface electronegativity, which promoted a good dispersion of the NPs. In vitro experiments demonstrated that OVA24-Pam3CSK4-UCNPs induced a strong immune response, including DC maturation, T cell activation, and proliferation, as well as interferon gamma (IFN-γ) production. In vivo, highly sensitive upconversion luminescence (UCL) imaging of OVA24-Pam3CSK4-UCNPs allowed tracking of UCNPs from the periphery to lymph nodes. In summary, OVA24-Pam3CSK4-UCNPs represent an effective tool for DC-based immunotherapy. GRAPHICAL ABSTRACT: [Image: see text] SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00604-022-05441-z
On optical black holes in moving dielectrics
We study the optical paths of the light rays propagating inside a nonlinear
moving dielectric media. For the rapidly moving dielectrics we show the
existence of a distinguished surface which resembles, as far as the light
propagation is concerned, the event horizon of a black hole. Our analysis
clarifies the physical conditions under which electromagnetic analogues of the
gravitational black holes can eventually be obtained in laboratory.Comment: 5 pages, 2 figures, revtex
Verbalizing phylogenomic conflict: Representation of node congruence across competing reconstructions of the neoavian explosion
Phylogenomic research is accelerating the publication of landmark studies that aim to resolve deep divergences of major organismal groups. Meanwhile, systems for identifying and integrating the products of phylogenomic inference-such as newly supported clade concepts-have not kept pace. However, the ability to verbalize node concept congruence and conflict across multiple, in effect simultaneously endorsed phylogenomic hypotheses, is a prerequisite for building synthetic data environments for biological systematics and other domains impacted by these conflicting inferences. Here we develop a novel solution to the conflict verbalization challenge, based on a logic representation and reasoning approach that utilizes the language of Region Connection Calculus (RCC-5) to produce consistent alignments of node concepts endorsed by incongruent phylogenomic studies. The approach employs clade concept labels to individuate concepts used by each source, even if these carry identical names. Indirect RCC-5 modeling of intensional (property-based) node concept definitions, facilitated by the local relaxation of coverage constraints, allows parent concepts to attain congruence in spite of their differentially sampled children. To demonstrate the feasibility of this approach, we align two recent phylogenomic reconstructions of higher-level avian groups that entail strong conflict in the "neoavian explosion" region. According to our representations, this conflict is constituted by 26 instances of input "whole concept" overlap. These instances are further resolvable in the output labeling schemes and visualizations as "split concepts", which provide the labels and relations needed to build truly synthetic phylogenomic data environments. Because the RCC-5 alignments fundamentally reflect the trained, logic-enabled judgments of systematic experts, future designs for such environments need to promote a culture where experts routinely assess the intensionalities of node concepts published by our peers-even and especially when we are not in agreement with each other
Measurement of coherent charge transfer in an adiabatic Cooper pair pump
We study adiabatic charge transfer in a superconducting Cooper pair pump,
focusing on the influence of current measurement on coherence. We investigate
the limit where the Josephson coupling energy between the various parts
of the system is small compared to the Coulomb charging energy . In this
case the charge transferred in a pumping cycle , the charge of one
Cooper pair: the main contribution is due to incoherent Cooper pair tunneling.
We are particularly interested in the quantum correction to , which is due
to coherent tunneling of pairs across the pump and which depends on the
superconducting phase difference between the electrodes: . A measurement of tends to destroy the phase
coherence. We first study an arbitrary measuring circuit and then specific
examples and show that coherent Cooper pair transfer can in principle be
detected using an inductively shunted ammeter
The transition form factors for semi-leptonic weak decays of in QCD sum rules
Within the Standard Model, we investigate the semi-leptonic weak decays of
. The various form factors of transiting to a single charmed
meson () are studied in the framework of the QCD sum rules.
These form factors fully determine the rates of the weak semi-leptonic decays
of and provide valuable information about the non-perturbative QCD
effects. Our results indicate that the decay rate of the semi-leptonic weak
decay mode is at order of .Comment: 28 pages, 6 figures, revised version to be published in Eur.Phys.J.
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