Spin angular impulse due to spin-dependent reflection off a barrier

The spin-dependent elastic reflection of quasi two-dimensional electrons from a lateral impenetrable barrier in the presence of band-structure spin-orbit coupling results in a spin angular impulse exerted on the electrons which is proportional to the nontrivial difference between the electrons' momentum and velocity. Even for an unpolarized incoming beam we find that the spin angular impulse is nonzero when averaged over all components of the reflected beam. We present a detailed analysis of the kinematics of this process.Comment: 4 pages, 2 figures, final versio

AC logic flip-flop circuits Patent

Bistable multivibrator circuits operating at high speed and low power dissipatio

Transport user benefits calculation with the “Rule of a Half” for travel demand models with constraints

The importance of user benefits in transport projects assessments is well-known by transport planners and economists. Generally they have the greatest impact on the result of costbenefit analysis. It is common practice to adopt the consumer surplus measure for calculating transport user benefits. Normally the well-known “Rule of a Half”, as a practical approximation for the integral of the demand curve, is used to determine the change of consumer surplus. In this paper we enter into the question of whether the Rule of a Half is valid in the case of travel demand models with multiple constraints. Such models are often used for travel demand modeling of large-scale areas. The most discussed and well-known model in transport modeling field is the doubly constrained gravity model. Beside this model with inelastic constraints there are also more flexible models with elastic constraints. The theoretical analysis in this paper provides a mathematical proof for the validity of the concept of the Rule of a Half for travel demand models with multiple elastic and inelastic constraints. In this case the Rule of a Half is also a correct approximation of the change of consumer surplus

Error estimates for the finite element approximation of bilinear boundary control problems

In this article a special class of nonlinear optimal control problems involving a bilinear term in the boundary condition is studied. These kind of problems arise for instance in the identification of an unknown space-dependent Robin coefficient from a given measurement of the state, or when the Robin coefficient can be controlled in order to reach a desired state. To this end, necessary and sufficient optimality conditions are derived and several discretization approaches for the numerical solution the optimal control problem are investigated. Considered are both a full discretization and the postprocessing approach meaning that we compute an improved control by a pointwise evaluation of the first-order optimality condition. For both approaches finite element error estimates are shown and the validity of these results is confirmed by numerical experiments.Comment: 39 pages, 1 figur

An Artist's View of the History of Art from the Perspective of 'Analogic Representation'

This article is basically an artist's statement published in connection with a major interdisciplinary art project currently in development (completion date estimated to be 2020)

On the need for an international lender of last resort: Lessons from domestic financial markets

The increasing incidence and intensity of crises in the international financial markets during the 1990s have given new impetus to the debate on reform of the international financial system. Much of the discussion focuses on the idea of an international lender of last resort which could provide liquidity to ensure the stability of the international financial system. This paper responds to the question of whether an international lender of last resort is necessary by presenting both the differences and the similarities between a domestic financial market and an international one. This comparison will show that in regard to those aspects which justify the existence of a lender of last resort at the national level, the two types of financial markets are no different: If commercial banks are engaging in maturity and liquidity transformation, then the existence of a lender of last resort is a prerequisite to stable and crisis-free development of financial markets. Both the recent financial crises, and the developments which can be observed in the banking sectors of Latin America and Eastern Europe, provide empirical evidence for this thesis. In these regions, banking sectors are emerging which are increasingly dominated by foreign banks, and thus have indirect access to an international lender of last resort. At the same time, there is an increasing tendency within emerging markets to introduce regulations which limit the extent to which transformation is performed in financial markets, and thus to limit as far as possible the risks which make an international lender of last resort necessary. --lender of last resort,maturity transformation,liquidity transformation,financial crisis,currency crisis