11,968 research outputs found
A 35 GHz solid state transmitter/driver
Solid state transmitter/driver /multiplier/ signal source has been designed and fabricated to produce a stable crystal-controlled CW power output of 100 mw at 35 GHz
Data Management and Mining in Astrophysical Databases
We analyse the issues involved in the management and mining of astrophysical
data. The traditional approach to data management in the astrophysical field is
not able to keep up with the increasing size of the data gathered by modern
detectors. An essential role in the astrophysical research will be assumed by
automatic tools for information extraction from large datasets, i.e. data
mining techniques, such as clustering and classification algorithms. This asks
for an approach to data management based on data warehousing, emphasizing the
efficiency and simplicity of data access; efficiency is obtained using
multidimensional access methods and simplicity is achieved by properly handling
metadata. Clustering and classification techniques, on large datasets, pose
additional requirements: computational and memory scalability with respect to
the data size, interpretability and objectivity of clustering or classification
results. In this study we address some possible solutions.Comment: 10 pages, Late
Surface Plasmon Excitation of Second Harmonic light: Emission and Absorption
We aim to clarify the role that absorption plays in nonlinear optical
processes in a variety of metallic nanostructures and show how it relates to
emission and conversion efficiency. We define a figure of merit that
establishes the structure's ability to either favor or impede second harmonic
generation. Our findings suggest that, despite the best efforts embarked upon
to enhance local fields and light coupling via plasmon excitation, nearly
always the absorbed harmonic energy far surpasses the harmonic energy emitted
in the far field. Qualitative and quantitative understanding of absorption
processes is crucial in the evaluation of practical designs of plasmonic
nanostructures for the purpose of frequency mixing
Metals used in maxillofacial surgery
The goal of maxillofacial surgery is to restore the shape and functionality of maxillofacial region. In the past years, there has been a tremendous progress in this field because of significant advances in biotechnology that provided innovative biomaterials to efficiently reconstruct the maxillofacial injured region. By using appropriate selection of the implant biomaterial, it is possible to reconstruct the native tissue, both in form and function. The ideal biomaterial should mimic native tissues regarding density, strength, and modulus of elasticity. Autografts are currently the gold standard for replacement of missing tissues, but synthetic biomaterials have been widely used because they eliminate the discomfort to take the replacement tissue from the donor site. Among synthetic biomaterials, different metals may be utilized to efficiently reconstruct the maxillofacial injured region. This article makes an effort to summarize the most important metals in use in maxillofacial surgery, and point out advantages and disadvantage of each typ
Light quark hadrons in hadronic Z decays
The results on the inclusive production of light quark hadrons in the hadronic decays of the Z are reviewed. Particular attention is paid to the new results on the inclusive production in Z -> bbbar events
Two topics in multiparticle dynamics at LEP: multiplicity in bb events and screwiness at the end of the QCD cascade
This talk deals with two topics in multiparticle dynamics investigated by means of the DELPHI detector at LEP. Related to the first topic, we have used the data collected at 183 GeV to measure the average charged particle multiplicity in e/sup +/e/sup -/ to bb events. The result is remarkably in agreement with QCD predictions, while it is more than two standard deviations larger than calculations assuming that the multiplicity accompanying the decay of a heavy quark is independent of the mass of the quark itself. The second topic deals with a recent theoretical model by Andersson et al. (1998), in which soft gluons order themselves in the form of a helix at the end of the QCD cascades. In our data at the Z peak, we have found no evidence for such an effect. (26 refs)
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