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971.
To detect database records containing approximate and exact duplicates because of data entry error or differences in the detailed
schemas of records from multiple databases or for some other reasons is an important line of research. Yet no comprehensive
comparative study has been performed to evaluate the effectiveness of Silhouette width, Calinski & Harbasz index (pseudo F-statistics)
and Baker & Hubert index (γ index) algorithms for exact and approximate duplicates. In this paper, a comparative study and effectiveness of these three
cluster validation techniques which involve measuring the stability of a partition in a data set in the presence of noise,
in particular, approximate and exact duplicates are presented. Silhouette width, Calinski & Harbasz index and Baker & Hubert
index are calculated before and after inserting the exact and approximate duplicates (deliberately) in the data set. Comprehensive
experiments on glass, wine, iris and ruspini database confirms that the Baker & Hubert index is not stable in the presence
of approximate duplicates. Moreover, Silhouette width, Calinski and Harbasz index and Baker & Hubert indice do not exceed
the original data indice in the presence of approximate duplicates. 相似文献
972.
Gotluru Kedarnath Liladhar B. Kumbhare Sandip Dey Amey P. Wadawale Vimal K. Jain Goutam K. Dey 《Polyhedron》2009,28(13):2749-2753
The reactions of Pb(OAc)2·3H2O with NaER yield homoleptic colorless to yellow complexes of composition, [Pb(ER)2] (ER = SCH2CH2NMe2 (1), SeCH2CH2NMe2 (2) and SeCH2CH2COOMe (3)). These complexes were characterized by elemental analyses, UV–Vis and 1H NMR data. Molecular structures of [Pb(ECH2CH2NMe2)2] (E = S or Se) have been established by single crystal X-ray diffraction analyses. These molecules have a distorted trigonal bipyramidal configuration around lead with the nitrogen atoms of the chelating chalcogenolate ligands occupying the axial positions. Thermal behavior of these complexes was studied by TG analysis. Pyrolysis in a furnace or in HDA (hexadecylamine) gave PbE nanoparticles which were characterized by UV–Vis, photoluminescence, XRD, EDAX, and TEM measurements. 相似文献
973.
The brownmillerite-type layered compound Ca2.375La0.125Sr0.5GaMn2O8 has been synthesized. The crystal and magnetic structures have been refined by the Rietveld analysis of the neutron powder diffraction patterns at 300 and 20 K. This compound crystallizes in the orthorhombic symmetry under the space group Pcm21 (a = 5.447(2), b = 11.359(4) and c = 5.322(2) Å). The compound is found to be antiferromagnetic at 20 K. The ordered Mn magnetic moment, aligned along the crystallographic b-direction, is derived to be 2.53(5) µB per Mn ion at 20 K. 相似文献
974.
Darshan Chetan Jain Sumit Dogra Manu Gupta Munish Kumar Mia Mozammel 《Journal of Thermal Analysis and Calorimetry》2019,138(1):273-285
Journal of Thermal Analysis and Calorimetry - Machinability of Inconel-718 superalloy in conventional approach is poor—this fact necessitates advanced technological adoption such as improved... 相似文献
975.
976.
977.
Most of the procedures employed so far in the literature for obtaining the amorphous volume of a polymer below its melting point have been based upon some kind of ad hoc assumptions. In this paper the principle of corresponding states, whose validity has been established for a number of polymers, is applied for obtaining the amorphous volume of polyethylene in the experimentally inaccessible region. The degree of crystallinity as a function of temperature is then calculated in a typical case using the actual sample volume data of Quinn and Mandelkern and the ideal crystal volume values obtained from X-ray measurements. Our results indicate the onset of a prominent relaxational transition at T1 = 152°K. A careful analysis of the volume-temperature relationship indicates a much weaker transition at T2 = 233°K. By making use of the isoprene volume concept, it is shown that the Simha-Boyer relation is valid in a more general form. 相似文献
978.
M. P. Kamath A. P. Kulkarni S. Jain P. K. Tripathi A. S. Joshi P. A. Naik P. D. Gupta 《Pramana》2010,75(5):883-888
Optical diagnostics of laser-produced plasma requires a coherent, polarized probe beam synchronized with the pump beam. The
probe beam should have energy above the background emission of plasma. Though the second harmonic probe beam satisfies most
of the requirements, the plasma emission is larger at the harmonic frequencies of the pump. Hence, at high intensities we
need a probe beam at non-harmonic frequencies. We have set up a Raman frequency shifted probe beam using a pressurized hydrogen
cell that is pumped by the second harmonic of the Nd glass laser that operates at only one Stokes line of 673.75 nm. 相似文献
979.
Ricky Jain Steven L. Girshick Joachim V. Heberlein Rajesh Mukherjee Bin Zhang Toshitaka Nakamura Amane Mochizuki 《Plasma Chemistry and Plasma Processing》2010,30(6):795-811
Advanced phosphor materials such as cerium-doped yttrium aluminum garnet (YAG) are of interest for a variety of applications,
including light-emitting diodes. Previous studies have shown that it is difficult to produce the desired YAG phase without
ex-situ annealing irrespective of the synthesis technique used. This study focuses on direct synthesis of YAG phosphor particles
using an inductively coupled thermal plasma system with a ceramic tube inserted coaxially into the chamber. Numerical modeling
indicates that the tube provides a more uniform high-temperature region, without flow recirculation. This is hypothesized
to aid in size and phase control through selective particle collection and in-flight annealing. Experiments conducted with
the tube-insertion setup indicate that phase and size control of the particles is possible to a certain extent, depending
on the size of the tube. Characterization results of the synthesized particles showed that submicron-sized YAG particles are
synthesized as the majority phase through the tube-insertion setup. 相似文献
980.
We report fluorescence quenching of the conjugated polymer poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylenevinylene (MDMO-PPV) in the presence of nitrated explosives, such as, 2,4,6-trinitrotoluene (TNT). It is found that the conjugated polymer changes color from orange to brownish black when sprayed on traces of TNT within a few seconds. Fluorescence quenching of the conjugated polymer in the presence of TNT is also studied by absorption and emission spectroscopy. The conjugated polymer is highly selective for sensing TNT in daylight and ambient conditions. 相似文献