Quantized transport, strain-induced perfectly conducting modes and valley filtering on shape-optimized graphene Corbino devices

The extreme mechanical resilience of graphene and the peculiar coupling it hosts between lattice and electronic degrees of freedom have spawned a strong impetus towards strain-engineered graphene where, on the one hand, strain augments the richness of its phenomenology and makes possible new concepts for electronic devices and, on the other hand, new and extreme physics might take place. Here, we demonstrate that the shape of substrates supporting graphene sheets can be optimized for approachable experiments where strain-induced pseudomagnetic fields (PMF) can be tailored by pressure for directionally selective electronic transmission and pinching-off of current flow down to the quantum channel limit. The Corbino-type layout explored here furthermore allows filtering of charge carriers according to valley and current direction, which can be used to inject or collect valley-polarized currents, thus realizing one of the basic elements required for valleytronics. Our results are based on a framework developed to realistically determine the combination of strain, external parameters, and geometry optimally compatible with the target spatial profile of a desired physical property --- the PMF in this case. Characteristic conductance profiles are analyzed through quantum transport calculations on large graphene devices having the optimal shape.Comment: 5+7 figures. Supporting information include

Comprehensive User Engagement Sites (CUES) in Philadelphia: A Constructive Proposal

This paper is a study about Philadelphia’s comprehensive user engagement sites (CUESs) as the authors address and examine issues related to the upcoming implementation of a CUES while seeking solutions for its disputed questions and plans. Beginning with the federal drug schedules, the authors visit some of the medical and public health issues vis-à-vis safe injection facilities (SIFs). Insite, a successful Canadian SIF, has been thoroughly researched as it represents a paradigm for which a Philadelphia CUES can expand upon. Also, the existing criticisms against SIFs are revisited while critically unpackaged and responded to in favor of the establishment. In the main section, the authors propose the layout and services of the upcoming CUES, much of which would be in congruent to Vancouver’s Insite. On the other hand, the CUES would be distinct from Insite, as the authors emphasize, in that it will offer an information center run by individuals in recovery and place additional emphasis on early education for young healthcare professionals by providing them a platform to work at the site. The paper will also briefly investigate the implementation of a CUES site under an ethical scope of the Harm Reduction Theory. Lastly, the authors recommend some strategic plans that the Philadelphia City government may consider employing at this crucial stage

Congress Needs to Find a Productive Role in Restoring Confidence to Our Financial System

As our very resilient economy begins the long road to recovery, we will need to evaluate the lessons learned from the financial market turmoil.Senate, banking, Senate Banking Committee, GSE, discal discipline, financial system, federal, congress, confidence

Analysing pedagogical change: Physics teachers' responses to a new curriculum.

This paper describes teachers' attempts to implement the 1994 New Zealand physics curriculum in the first year of its introduction to secondary schools in 1998. Analysis of interviews with 10 physics teachers and the three curriculum writers led to the identification of a number of barriers to changes in pedagogical practices. The barriers identified aligned with factors that had been identified by other researchers as important influences on teachers undergoing change. It is argued that a sociocultural perspective suggests that there were three main reasons why significant pedagogical change was not occasioned by the curriculum document. Firstly, there was very limited knowledge about why changes were being implemented. Secondly, there was little social and system support for the curriculum change. Finally, teachers had no time to focus on and reflect on the change

A Certain Amount of the Unknown - The Argument of the Bodily in Don DeLillo

Zadanie pt. „Digitalizacja i udostępnienie w Cyfrowym Repozytorium Uniwersytetu Łódzkiego kolekcji czasopism naukowych wydawanych przez Uniwersytet Łódzki” nr 885/P-DUN/2014 dofinansowane zostało ze środków MNiSW w ramach działalności upowszechniającej nauk

Multiphase gas in the circumgalactic medium: relative role of tcool/tfft_{\rm cool}/t_{\rm ff} and density fluctuations

We perform a suite of simulations with realistic gravity and thermal balance in shells to quantify the role of the ratio of cooling time to the free-fall time ($t_{\rm cool}/t_{\rm ff}$) and the amplitude of density perturbations ($\delta \rho/\rho$) in the production of multiphase gas in the circumgalactic medium (CGM). Previous idealized simulations, focussing on small amplitude perturbations in the intracluster medium (ICM), found that cold gas can condense out of the hot ICM in global thermal balance when the background $t_{\rm cool}/t_{\rm ff} \lesssim 10$. Recent observations suggest the presence of cold gas even when the background profiles have somewhat large values of ${t_{\rm cool}/t_{\rm ff}}$. This partly motivates a better understanding of additional factors such as large density perturbations that can enhance the propensity for cooling and condensation even when the background ${t_{\rm cool}/t_{\rm ff}}$ is high. Such large density contrasts can be seeded by galaxy wakes or dense cosmological filaments. From our simulations, we introduce a condensation curve in the $(\delta \rho/\rho)$ - min$(t_{\rm cool}/t_{\rm ff})$ space, that defines the threshold for condensation of multiphase gas in the CGM. We show that this condensation curve corresponds to ${(t_{\rm cool}/t_{\rm ff})}_{\rm blob} \lesssim 10$ applied to the overdense blob instead of the background for which $t_{\rm cool}/t_{\rm ff}$ can be higher. We also study the modification in the condensation curve by varying entropy stratification. Steeper (positive) entropy gradients shift the condensation curve to higher amplitudes of perturbations (i.e., make condensation difficult). A constant entropy core, applicable to the CGM in smaller halos, shows condensation over a larger range of radii as compared to the steeper entropy profiles in the ICM.Comment: 17 pages, 14 figures, 2 tables, the version accepted in MNRA

Research on the Problems and Countermeasures of Using Management Accounting Methods to Promote the Reform of State-owned Enterprises

This paper deeply discusses how to use the power of management accounting to promote the deepening of the reform of state-owned enterprises, and proposes effective solutions to the existing problems. The reform of state-owned enterprises, as an indispensable part of China's economic map, is of great importance. Management accounting, as a mature and efficient management tool, is gradually becoming an indispensable supporting force in the reform of state-owned enterprises. This paper provides an in-depth analysis of the unique role of management accounting in the reform of state-owned enterprises. We find that by introducing management accounting concepts and methods, we can effectively optimize resource allocation, improve decision-making efficiency, and inject new vitality into the reform of state-owned enterprises. The research results of this paper are of great significance for guiding the reform practice of state-owned enterprises and improving the operating performance of state-owned enterprises. We believe that with the help of management accounting, the reform of state-owned enterprises will be able to take more solid steps and contribute more to the sustainable development of China's economy