3,184 research outputs found
Comparative analysis of different preparation methods of chalcogenide glasses: Molecular dynamics structure simulations
Two different preparation methods (liquid-quenching and evaporation) of
chalcogenide glasses have been investigated by molecular dynamics simulations.
Our particular aim was to determine how the structural changes occur due to the
different preparation methods. We applied a classical empirical three-body
potential of selenium to describe the interactions between atoms.
Our simulation shows that a significant difference can be observed in the
homogeneities
Physical rehabilitation for critical illness myopathy and neuropathy (Protocol)
Protocol for a review - no abstract
RG transport theory for open quantum systems: Charge fluctuations in multilevel quantum dots in and out of equilibrium
We present the real-time renormalization group (RTRG) method as a method to
describe the stationary state current through generic multi-level quantum dots
with a complex setup in nonequilibrium. The employed approach consists of a
very rudiment approximation for the RG equations which neglects all vertex
corrections while it provides a means to compute the effective dot Liouvillian
self-consistently. Being based on a weak-coupling expansion in the tunneling
between dot and reservoirs, the RTRG approach turns out to reliably describe
charge fluctuations in and out of equilibrium for arbitrary coupling strength,
even at zero temperature. We confirm this in the linear response regime with a
benchmark against highly-accurate numerically renormalization group data in the
exemplary case of three-level quantum dots. For small to intermediate bias
voltages and weak Coulomb interactions, we find an excellent agreement between
RTRG and functional renormalization group data, which can be expected to be
accurate in this regime. As a consequence, we advertise the presented RTRG
approach as an efficient and versatile tool to describe charge fluctuations
theoretically in quantum dot systems
Extensions of Power Transition: Applications to Political Economy
This is a paper about theory in political economy terms and political economy in theoretical terms. It unifies power transition theory and applies it to the central questions that now confront political economists. Will trade wars emerge as the security challenge declines? What are the economic effects of integration, trade and growth? How will economic patterns influence international power relationships? This paper offers a preliminary bridge whereon practitioners and theorist may meet to assess the challenges that lie at the intersection between politics and economics. The economic collapse and political dissolution of the Soviet Union left policymakers and scholars searching for new fundamentals about the nature of the international system. During the Cold War era the supreme threat to international peace and security overshadowed economic concerns. The nature of that threat was a powerful mobilizing tool for government, business, and society. The loss of the immediate security threat has forced policymakers to search for explanations which fit the new international circumstances without violating old, cherished and proven concepts. In the last 10 years the foreign policy community has gone through a difficult and wrenching exercise. The sense of uncertainty about the future of the new world stems not just from the radical changes it has undergone, but equally from the realization that the new environment requires the same level understanding of the politics of security and the politics of economics. This paper is designed to accomplish two goals. First, it offers the reader a composite picture of power transition theory, integrating the various extensions and amplifications into a coherent whole. It brings together that new research and weaves it into the rich text of the underlying theory. By providing a systematic outline of the hierarchical relationship among power and satisfaction we offers a foundation for exploring conflictual and economic interactions in world politics
Structure and photo-induced volume changes of obliquely deposited amorphous selenium
Atomic scale computer simulations on structures and photo induced volume
changes of flatly and obliquely deposited amorphous selenium films have been
carried out in order to understand how the properties of chalcogenide glasses
are influenced by their preparation method. Obliquely deposited a-Se thin films
contain more coordination defects, larger voids than the flatly deposited ones.
To model the photo induced volume changes the electron excitation and hole
creation were treated independently within the framework of tight-binding
formalism. Covalent and interchain bond breakings and formations were found.
The obliquely deposited samples containing voids showed a wide spectrum of
photo induced structural changes in microscopic and volume changes in
macroscopic levels.Comment: 14 page
Use by the U.S. Nuclear Regulatory Commission of the Obviously Superior Criterion for Alternative Sites
In its consideration of alternative sites for new nuclear power plants, the U.S. Nuclear
Regulatory Commission (NRC) uses a standard that the applicantâs proposed site will not be
rejected in favor of an alternative site unless the NRC staff determines that the alternative site is
âobviously superiorâ to the proposed site1. In this paper I will summarize the historical
development of this standard and how this standard has fared in the courts. I will then examine
the extent to which this standard complies with the requirements of National Environmental
Policy Act (NEPA) of 1969, as amended2 and the associated regulations published by the
Council on Environmental Quality3. I will also examine how the standard compares to the
approaches used by other agencies, such as the U.S. Army Corps of Engineers (which uses a
standard of the least environmentally damaging practicable alternative). In conclusion, I will
discuss whether the NRC should consider modifying the standard either because of challenges to
its past implementation, or foreseeable changes in future implementation
GDP Data Revisions and Forward-Looking Monetary Policy in Switzerland
This paper analyzes forward-looking rules for Swiss monetary policy in a small structural VAR model consisting of four variables taking into account data revisions for GDP. First, the paper develops an analytical method to analyze the effect of data revision errors in GDP on the ex ante or conditional inflation-output-growth volatility trade-off and applies it to Swiss data. Second, the effects of different targets in a forward-looking monetary policy on ex post or unconditional volatility of inflation and output growth is explored by a simulation exercise. In general, the results obtained suggest that focusing monetary policy on GDP growth instead on inflation may lead to an inefficient policy with both increased medium term inflation and GDP growth volatility in the presence of GDP data revisions.Structural VAR, forward-looking monetary policy, efficiency frontier, GDP data revisions
The Analysis of Forward-Looking Monetary Policy in a SVAR Framework
This paper analyzes forward-looking monetary policy rules in structural VARâs. First, an approach for modeling a monetary policy which aims at a strict medium term inflation or output growth target is developed. Second, the ex ante inflation-output-growth volatility trade-off for a forward-looking policy aiming at a convex combination these strategies is derived. Finally, an illustration of our approach using Swiss data is given.Structural VAR, forward-looking monetary policy, efficiency frontier
Measurement errors in GDP and forward-looking monetary policy: The Swiss case
This paper analyzes forward-looking rules for Swiss monetary policy in a small structural VAR consisting of four variables. First, the paper looks at the ex ante inflation-output-growth volatility trade-off for a forward-looking policy aiming at a convex combination of a strict inflation and output growth targeting rule implied by this SVAR model. Thereby the paper introduces a new analytical method. Second, the paper considers the effect of measurement errors in GDP on this inflation-output-growth volatility trade-off. Third, the paper works at the impact of changing beliefs about the potential growth rate on the variability of output growth and inflation. Finally the effects of different targets in a forward-looking monetary policy on ex post or unconditional volatility of inflation and output growth is explored by a simulation exercise. --Structural VAR,forward-looking monetary policy,efficiency frontier,GDP measurement errors
Derivation of exact flow equations from the self-consistent parquet relations
We exploit the parquet formalism to derive exact flow equations for the
two-particle-reducible four-point vertices, the self-energy, and typical
response functions, circumventing the reliance on higher-point vertices. This
includes a concise, algebraic derivation of the multiloop flow equations, which
have previously been obtained by diagrammatic considerations. Integrating the
multiloop flow for a given input of the totally irreducible vertex is
equivalent to solving the parquet equations with that input. Hence, one can
tune systems from solvable limits to complicated situations by variation of
one-particle parameters, staying at the fully self-consistent solution of the
parquet equations throughout the flow. Furthermore, we use the resulting
differential form of the Schwinger-Dyson equation for the self-energy to
demonstrate one-particle conservation of the parquet approximation and to
construct a conserving two-particle vertex via functional differentiation of
the parquet self-energy. Our analysis gives a unified picture of the various
many-body relations and exact renormalization group equations
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