48,999 research outputs found
Three-point bridge calibration with one resistor
Method calibrates transducer bridge curing unbalanced condition and line resistance errors are negligible. Series resistance method can be automated easily and controlled by 2-bit information source which provide 4 states for switches
Spin-density wave Fermi surface reconstruction in underdoped YBa2Cu3O6+x
We consider the reconstruction expected for the Fermi surface of underdoped
YBa2Cu3O6+x in the case of a collinear spin-density wave with a characteristic
vector Q=(pi[1+/-2 delta],pi), assuming an incommensurability delta~0.06
similar to that found in recent neutron scattering experiments. A Fermi surface
possibly consistent with the multiple observed quantum oscillation frequencies
is obtained. From the low band masses expected using this model as compared
with experiment, a uniform enhancement of the quasiparticle effective mass over
the Fermi surface by a factor of ~7 is indicated. Further predictions of the
Fermi surface topology are made, which may potentially be tested by experiment
to indicate the relevance of this model to underdoped YBa2Cu3O6+x.Comment:
Investigating Nonlinearity: A Note on the Implementation of Hamilton's Methodology
In this paper we give an account of the new approach to nonlinear econometric modelling proposed by Hamilton (2001) and briefly describe some of the methods of nonlinear optimization that may be used in the Gauss computer program provided by Hamilton for the implementation of his methodology. The performance of this program is investigated using data relating to Hamilton's example concerning the US Phillips curve, two versions of the Gauss software and a range of alternative numerical optimization options and values for the important Gauss parameter _oprteps. Finally, the effects of changes in the sample data on the results produced by Hamilton's procedure are explored. The results presented suggest some clear conclusions, which will be of value to those contemplating working with Hamilton's new method.
Probabilistic models of planetary contamination
Likely fundamental inadequacies in the model of planetary contamination advanced by Sagan and Coleman are discussed. It is shown that a relatively minor modification of the basic Sagan-Coleman formula yields approximations that are generally adequate with data in the range of interest. This approximation formula differs from the original Sagan-Coleman version only through an initial conditioning on landing outcome. It always yields an upper (conservative) bound for the total probability of contamination, this appealing feature is lost if the conditioning on landing outcome is deleted
Some new results on decidability for elementary algebra and geometry
We carry out a systematic study of decidability for theories of (a) real
vector spaces, inner product spaces, and Hilbert spaces and (b) normed spaces,
Banach spaces and metric spaces, all formalised using a 2-sorted first-order
language. The theories for list (a) turn out to be decidable while the theories
for list (b) are not even arithmetical: the theory of 2-dimensional Banach
spaces, for example, has the same many-one degree as the set of truths of
second-order arithmetic.
We find that the purely universal and purely existential fragments of the
theory of normed spaces are decidable, as is the AE fragment of the theory of
metric spaces. These results are sharp of their type: reductions of Hilbert's
10th problem show that the EA fragments for metric and normed spaces and the AE
fragment for normed spaces are all undecidable.Comment: 79 pages, 9 figures. v2: Numerous minor improvements; neater proofs
of Theorems 8 and 29; v3: fixed subscripts in proof of Lemma 3
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Manufacturing flexible light-emitting polymer displays with conductive lithographic film technology
We report on a new low-cost manufacturing process for flexible displays that has the potential to rapidly expand the market into areas that have traditionally been outside the scope of such technology. In this paper we consider the feasibility of using offset-lithography to deposit contacts for polymer light-emitting displays. We compare and contrast manufacturing criteria and present a case study detailing our initial results. It is expected that these developments will stimulate further progress in multilayer device
fabrication.
Cheap, flexible conductive interconnects have the potential to find applications in a wide variety of device structures. For the more challenging exploitation areas in multilayer devices, such as displays, it was found that the properties of conductive lithographic films were not optimal in their current form. Three parameters (conductivity, surface roughness and surface work function) were identified as critical to device fabrication. Calendering and electroless plating were investigated as methods to improve these properties. Both methods aimed to modify the surface roughness and conductivity, with the plating study also modifying the work function
Capital Structure and Political Risk in Asia-Pacific Real Estate Markets
This study investigates the determinants of capital structure decisions by real estate firms, with a specific focus on the impact of political risk on leverage. Using a sample of Asia-Pacific REITs and listed property trusts, we find those firms with properties located in countries characterized by relatively high degrees of political risk, such as political instability, and/or greater uncertainty in the ability to repatriate and monetize profits from international investment activities, employ less debt than their counterparts operating in more politically stable environments. This core finding remains robust to alternative sample selection criteria including the division of the sample into high versus low market-to-book value firms, and also holds within the subset of organizations that are active in raising additional capital in the secondary markets
Advisor Choice in Asia-Pacific Property Markets
This paper examines advisor choice decisions by publicly traded REITs and listed property companies in Asia-Pacific real estate markets. Using a sample of 168 firms, we find robust evidence that firms strategically evaluate and compare the increased agency costs associated with external advisement against the potential benefits associated with collocating decision rights with location specific soft information. Our empirical results reveal real estate companies tend to hire external advisors when they invest in countries: 1) that are more economically and politically unstable, 2) whose legal system is based on civil law, 3) where the level of corruption is perceived to be high, and 4) when disclosure is relatively poor. Additionally, we find the probability of retaining an external advisor is directly related to the expected agency costs. Lastly, we find evidence of return premiums in excess of 13 % for firms whose organizational structure matches their investment profile. As such, we conclude that the decision to hire an external advisor represents a value relevant trade-off between the costs and benefits of this organizational arrangement
Clawback Provisions in Real Estate Investment Trusts
Using a sample of 195 unique real estate investment trusts (REITs), we examine factors related to the adoption of clawback provisions within managerial compensation contracts. In general, we find strong and consistent empirical evidence that clawback provision are directly related to firm size, complexity, leverage, growth options, monitoring incentives, and CEO performance incentives. We also find that clawbacks are associated with enhanced market and accounting performance, with stronger performance relations observed for adoption decisions tied directly to regulatory mandates. In sum, we conclude compensation clawback provisions represent a value-relevant, strategic governance mechanism for REITs
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