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991.
We demonstrate how optimization problems arise in the field of pattern classification, in particular in using piecewise-linear classification and classification based on an optimal linear separator. We motivate the need in this area for a general purpose optimization approach. We discuss ALOPEX, a biased random search approach, from the point of view of this need. While ALOPEX itself failed to fulfil our need, a newly-introduced generalization of it (iterated ALOPEX) was found to be appropriate for the optimization problems of our particular concern. We conclude the paper with a brief critical evaluation of this approach as compared to our original aims. 相似文献
992.
Mathematical Notes - 相似文献
993.
Naba K. Mondal 《Pramana》1998,51(1-2):65-76
In this article, we review some of the recent results from CDF and DØ experiments at the Tevatron and their prospects at the upgrade. Among the topics discussed are top quark physics, electroweak physics, qcd physics and new physics beyond standard model. 相似文献
994.
The 351 nm laser-damage thresholds (at 0.7 nm pulse length) of monomeric liquid crystals are reported and results from aromatic-core samples are compared with those from fully saturated systems. The role of π-electron conjugation is examined and identified as the key cause for laser damage. For UV laser compatibility of devices, the damage behaviour of an alignment-layer polymer (nylon 6/6) was also investigated. 相似文献
995.
Y2BaCuO5 (211) inclusions are prominent microstructural features found in melt-textured YBa2Cu3Ox (123) superconductors. These particles are of interest because the 123/211 interfaces and the interface-associated defects have been proposed to be flux pinning centers. In addition, the 211 particles are believed to be heterogeneous nucleation centers of dislocation which can increase the critical current density of 123. Unfortunately, only limited studies have been performed on these particles to ascertain their roles in flux pinning. In this investigation, 211 particles, the interfacial structure and defects in undeformed and mechanically deformed melt-textured 123 have been studied by transmission electron microscopy. It was found that there appears to be a preferred orientation between large oblong 211 particles and the 123 matrix. In addition, while the 123/211 interfaces in undeformed 123 are sharp and relatively undistorted, the interfaces in deformed 123 samples are much thicker. Also, the distribution of strained regions and dislocations around oblong 211 particles in undeformed 123 is nonuniform; the interfaces of low surface curvature are relatively free of defects while the surfaces of high curvature are abundant in dislocations. In contrast, the 123/211 interfaces in deformed 123 samples contain high density of dislocations regardless of interface curvature. 相似文献
996.
K. M. A. Salam Hidekazu Konishi Masahiro Mizuno Hisashi Fukuda Shigeru Nomura 《Applied Surface Science》2002,190(1-4):88-95
Polycrystalline (1−x)Ta2O5−xTiO2 thin films were formed on Si by metalorganic decomposition (MOD) and annealed at various temperatures. As-deposited films were in the amorphous state and were completely transformed to crystalline after annealing above 600 °C. During crystallization, a thin interfacial SiO2 layer was formed at the (1−x)Ta2O5−xTiO2/Si interface. Thin films with 0.92Ta2O5–0.08TiO2 composition exhibited superior insulating properties. The measured dielectric constant and dissipation factor at 1 MHz were 9 and 0.015, respectively, for films annealed at 900 °C. The interface trap density was 2.5×1011 cm−2 eV−1, and flatband voltage was −0.38 V. A charge storage density of 22.8 fC/μm2 was obtained at an applied electric field of 3 MV/cm. The leakage current density was lower than 4×10−9 A/cm2 up to an applied electric field of 6 MV/cm. 相似文献
997.
On range searching with semialgebraic sets 总被引:1,自引:0,他引:1
998.
B. M. Forster J. M. Bailey G. A. Beer J. L. Beveridge J. H. Brewer W. N. Hardy T. M. Huber K. R. Kendall A. R. Kunselman J. A. Macdonald G. M. Marshall G. R. Mason A. Olin M. Senba J. B. Warren 《Hyperfine Interactions》1991,65(1-4):1007-1013
Muonic hydrogen isotopes (μ− p, μ− d, and μ−t) are simple quantum mechanical systems ideally suited for studies of numerous fundamental phenomena in electroweak and strong
interactions as well as in applied areas such as muon chemistry or muon catalyzed fusion.
Emission of muonic hydrogen isotopes into vacuum helps to overcome the limitations which are normally imposed on conventional
investigations with gaseous and liquid targets. A proof of principle experiment for this new technique was performed at TRIUMF
last year. Negative muons with 30 MeV/c momentum were stopped in a thin film of solid hydrogen and produced very low energy μ−d in vacuum. The distribution center of the normal velocity components of emitted μ−d atoms was measured to be ∼1 cm/μs. The yield of μ−d in vacuum is an increasing function of H2 film thickness δ up to a value of δ≥1 mm. 相似文献
999.
This paper reports the results of a survey intended to discover the extent to which Checkland's Soft Systems Methodology (SSM) is used in practice. Some 300 questionnaires were sent to people who had had some exposure to SSM and, surprisingly, nearly half were returned. The majority described in detail their uses of SSM and most felt that it had been successful. This paper describes the overall quantitative results from the survey as well as presenting a qualitative analysis of the experiences of using SSM. 相似文献
1000.
The synthesis and characterization of metal poly-yne polymers containing disilane, disiloxane and phosphine groups in the main chain are described. The platinum and palladium poly-yne polymers were synthesized by polycondensation reactions between a metal chloride and an α, ω-bisethynyl complex in amines in the presence of cuprous iodide as a catalyst. The nickel poly-yne polymers were synthesized by an alkynyl ligand exchange reaction between a nickel acetylide and an α, ω-bisethynyl complex in diethylamine in the presence of cuprous iodide as a catalyst. The reaction of the platinum poly-yne polymer, containing disiloxane groups in the main chain, with copper (I) salts afforded adducts of η-2-bonded σ-acetylide polymer complexes. The reactions of the palladium poly-yne polymer, containing phosphine groups in the main chain, with transition-metal carbonyl complexes afforded polymer complexes which have phosphorus in the main chain-transition-metal bonds. A concentrated solution of the platinum poly-yne polymer containing disiloxane groups in the main chain forms a lyotropic liquid crystal in dichloromethane or 1, 2-dichloroethane. 相似文献