Boundary States in Graphene Heterojunctions

A new type of states in graphene-based planar heterojunctions has been studied in the envelope wave function approximation. The condition for the formation of these states is the intersection between the dispersion curves of graphene and its gap modification. This type of states can also occur in smooth graphene-based heterojunctions.Comment: 5 pages, 3 figure

Partial Regularity of solutions to the Four-dimensional Navier-Stokes equations at the first blow-up time

The solutions of incompressible Navier-Stokes equations in four spatial dimensions are considered. We prove that the two-dimensional Hausdorff measure of the set of singular points at the first blow-up time is equal to zero.Comment: 19 pages, a comment regarding five or higher dimensional case is added in Remark 1.3. accepted by Comm. Math. Phy

Conceptual aspects of QCD factorization in hadronic B decays

I review the meaning of ``QCD factorization'' in hadronic two-body B decays and then discuss recent results of theoretical (rather than phenomenological) nature: the proof of factorization at two loops; the identification of ``chirally enhanced'' power corrections; and the role of annihilation contributions.Comment: 10 pages, LaTeX. Based on talks presented at the UK Phenomenology Workshop on Heavy Flavour and CP Violation, 17 - 22 September 2000, Durham, proceedings to appear in J. Phys. G; the 5th International Symposium on Radiative Corrections (RADCOR2000), Carmel, California, September 11 - 15, 2000; the 4th Workshop on Continuous Advances in QCD, Minneapolis, 12-14 May 2000; the Vth International Workshop on Heavy Quark Physics, Dubna, 6-8 April 200

A review of the six-minute walk test: Its implication as a self-administered assessment tool

Promoting self-management and monitoring physical activity are important strategies in chronic heart disease (CHD) management. The six-minute walk test (6MWT) is a commonly used sub-maximal exercise test for measuring physical functional capacity. The aim of this paper is to review the current literature on 6MWT relating to methodological issues as well as exploring the potential of the protocol to be adopted as a self-administered exercise test. The Medline, CINAHL, Science Direct and the World Wide Web using the search engine Google, were searched for articles describing the administration, reliability and validity of the 6MWT. Findings of the integrative literature review the 6MWT is a simple, safe tool. To date, the capacity for self-administration of the 6MWT has not been investigated. Adapting the 6MWT as a patient-reported outcome measure may enhance the capacity, not only for clinicians to monitor functional status, but also promote self-management by enabling individuals to monitor changes in their functional capacity

QCD factorization for B -> PP

In this work, we give a detailed discussion for QCD factorization involved the complete chirally enhanced power corrections for B decays to two light pseudoscalar mesons, and present some detailed calculations of radiative corrections at the order of alpha_s. We point out that the infrared finiteness of the vertex corrections in the chirally enhanced power corrections requires twist-3 light-cone distribution amplitudes (LCDAs) of the light pseudoscalar symmetric. However, even in the symmetric condition, there is also logarithmic divergence from the endpoints of the twist-3 LCDAs in the hard spectator scattering. We point out that the decay amplitudes of B --> PP predicted by QCD factorization are really free of the renormalization scale dependence, at least at the order of alpha_s. At last, we briefly compare the QCD factorization with the generalized factorization and PQCD method.Comment: 31 pages, 3 eps figure

Signatures of Electronic Nematic Phase at Isotropic-Nematic Phase Transition

The electronic nematic phase occurs when the point-group symmetry of the lattice structure is broken, due to electron-electron interactions. We study a model for the nematic phase on a square lattice with emphasis on the phase transition between isotropic and nematic phases within mean field theory. We find the transition to be first order, with dramatic changes in the Fermi surface topology accompanying the transition. Furthermore, we study the conductivity tensor and Hall constant as probes of the nematic phase and its transition. The relevance of our findings to Hall resistivity experiments in the high-$T_c$ cuprates is discussed.Comment: 5 pages, 3 figure

Analytical model for large-scale design of sidewalk delivery robot systems

With the rise in demand for local deliveries and e-commerce, robotic deliveries are being considered as efficient and sustainable solutions. However, the deployment of such systems can be highly complex due to numerous factors involving stochastic demand, stochastic charging and maintenance needs, complex routing, etc. We propose a model that uses continuous approximation methods for evaluating service trade-offs that consider the unique characteristics of large-scale sidewalk delivery robot systems used to serve online food deliveries. The model captures both the initial cost and the operation cost of the delivery system and evaluates the impact of constraints and operation strategies on the deployment. By minimizing the system cost, variables related to the system design can be determined. First, the minimization problem is formulated based on a homogeneous area, and the optimal system cost can be derived as a closed-form expression. By evaluating the expression, relationships between variables and the system cost can be directly obtained. We then apply the model in neighborhoods in New York City to evaluate the cost of deploying the sidewalk delivery robot system in a real-world scenario. The results shed light on the potential of deploying such a system in the future