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191.
Janez Demšar 《Machine Learning》2010,78(3):421-428
Relief is a measure of attribute quality which is often used for feature subset selection. Its use in induction of classification
trees and rules, discretization, and other methods has however been hindered by its inability to suggest subsets of values
of discrete attributes and thresholds for splitting continuous attributes into intervals. We present efficient algorithms
for both tasks. 相似文献
192.
Aleš Gorkič Drago Kovačič Janez Diaci 《The International Journal of Advanced Manufacturing Technology》2009,42(1-2):138-144
We present an experiment where sonic waves generated during the laser engraving of printed circuit boards (PCB) were acquired and analyzed. The sonic waves were detected simultaneously using a microphone and a laser beam deflection probe. An efficient windowed peak-to-peak signal processing algorithm was developed to examine the relation between the detected signals and the engraving quality. The results of signal analysis were compared to the engraving surface topography, measured by means of optical microscopy with extended depth-of-field digital photography. The results show that it is possible to distinguish between shallow, good, and burnt engravings by examination of the acquired sonic signals. This observation opens the possibility of automated monitoring or even control of the process of laser engraving PCBs using sonic wave detection. 相似文献
193.
The paper presents results of an analysis of acoustic-emission (AE) signals obtained during laser cutting of a steel plates, which are frequently used in the production of automotive body components. In the course of laser cutting, continuous signals, which are related to the quality achieved of the laser cut, are measured. After laser cutting characteristic AE bursts in the specimen material, which are results of a thermal influence, can be detected. The presence of dross is an important indicator of poor quality of laser cutting. The investigation on laser cutting was conducted on an unalloyed steel DC04 sheet and on austenitic stainless steel X5CrNi18-10 sheet of 1.5 mm in thickness. The same physical mechanism in the cut formation at both steels, however, resulted in a considerable different cut quality, which was indicated by the AE signals captured after the cutting process. 相似文献
194.
Vid Bobnar Marko Hrovat Janez Holc Marija Kosec 《Journal of the European Ceramic Society》2009,29(4):725-729
All-ceramic lead-free percolative composite, comprising RuO2 with high electrical conductivity denoted as the conductive phase and ferroelectric (K, Na)NbO3 ceramics, was developed. Structural analysis revealed a uniform distribution of conductive ceramic grains within the ceramic matrix. Consequently, the dielectric response in the (K, Na)NbO3–RuO2 composite follows the predictions of the percolation theory. Thus, close to the percolation point exceptionally high values of the dielectric constant were obtained—values as high as 20,000 were detected at room temperature at 1 kHz. Fit of the data, obtained for samples of different compositions, revealed critical exponent and percolation point, which reasonably agree with the theoretically predicted values. 相似文献
195.
Martina Durcik Prof. Päivi Tammela Michaela Barančoková Assist. Prof. Tihomir Tomašič Assoc. Prof. Janez Ilaš Prof. Danijel Kikelj Nace Zidar 《ChemMedChem》2018,13(2):186-198
ATP‐competitive inhibitors of DNA gyrase and topoisomerase IV are among the most interesting classes of antibacterial drugs that are unrepresented in the antibacterial pipeline. We developed 32 new N‐phenylpyrrolamides and evaluated them against DNA gyrase and topoisomerase IV from E. coli and Staphylococcus aureus. Antibacterial activities were studied against Gram‐positive and Gram‐negative bacterial strains. The most potent compound displayed an IC50 of 47 nm against E. coli DNA gyrase, and a minimum inhibitory concentration (MIC) of 12.5 μm against the Gram‐positive Enterococcus faecalis. Some compounds displayed good antibacterial activities against an efflux‐pump‐deficient E. coli strain (MIC=6.25 μm ) and against wild‐type E. coli in the presence of efflux pump inhibitor PAβN (MIC=3.13 μm ). Here we describe new findings regarding the structure–activity relationships of N‐phenylpyrrolamide DNA gyrase B inhibitors and investigate the factors that are important for the antibacterial activity of this class of compounds. 相似文献
196.
Catalytically active surface of small nickel (min 99 wt%) plates for steam methane reforming was enhanced by successive temperature programmed oxidation−reduction (TPO−TPR) pretreatment and combined physical vapor deposition of Pt and Al2O3. The effect of annealing time, temperature, order and number of coatings on the catalytic activity was investigated by means of a pulse technique at the reaction temperature of 760 °C. The most active and stable surface phases resulted after the successively deposited layers of Pt, Al2O3, and Pt had been annealed for 12 h onto 2-cycle TPO−TPR pretreated nickel plate at the temperature of 700 °C in a circulating atmosphere of N2. The durability performance of the so-prepared surface phases on a specifically structured plate catalyst element (diameter 43 mm and length 42 mm) was tested in a tubular reactor for some 70 h in temperature range 500−650 °C. Deactivation was mainly caused by carbon surface deposition. 相似文献
197.
Harvey Amorín Hana Uršič Pablo Ramos Janez Holc Rodrigo Moreno Daniel Chateigner Jesús Ricote Miguel Algueró 《Journal of the American Ceramic Society》2014,97(2):420-426
Pb(Mg1/3Nb2/3)O3–PbTiO3 is used as a model system of perovskite solid solutions with very high piezoelectric response at tailored morphotropic phase boundaries to demonstrate the processing of textured ceramics by ceramic‐only technology. A novel homogeneous templated grain growth approach that uses conventional ceramic procedures and a single‐source nanocrystalline powder for the matrix and also for obtaining the templates is described. Two batches of (100) faceted cube‐shaped microcrystals with average sizes of 27 and 10 μm were successfully used as templates, and aligned by tape casting for the processing of <001>‐textured Pb(Mg1/3Nb2/3)O3–PbTiO3 piezoelectric ceramics. Materials with effective piezoelectric coefficients up to 1000 pC/N and ferroelectric properties approaching those of single crystals are obtained. 相似文献
198.
Darko Belavic Marina Santo Zarnik Janez Holc Marko Hrovat Marija Kosec Silvo Drnovsek Jena Cilensek Srecko Macek 《International Journal of Applied Ceramic Technology》2006,3(6):448-454
Lead zirconate titanate (PZT) is a piezoelectric material that can sense or respond to mechanical deformations and can be used in ceramic electro-mechanical systems (C-MEMS). The microstructural, electrical, and piezoelectric characteristics of thick PZT films on low-temperature cofired ceramics (LTCC) and alumina substrates were studied. The PZT composition was prepared with low-melting-point additives in order to decrease the sintering temperature and to be compatible with thick-film technology. The integration of the PZT thick-film materials on ceramic substrates could lead to degradation of the PZT's characteristics due to the interactions between an active PZT layer and a substrate, particularly with glassy LTCC material. To minimize the interactions with LTCC substrates, an intermediate PZT barrier layer was integrated. The value of the piezoelectric coefficient d 33 was found to be up to 120 pC/N on an alumina substrate and approximately 50 on an LTCC substrate. Based on these results, a cantilever-type actuator was designed and fabricated on alumina substrates. Under an applied voltage of 200 V, the maximum tip deflection was about 5 μm. 相似文献
199.
Marko Hrovat Darko Belavi
Jaroslaw Kita Janez Holc Jena Cilenek Silvo Drnovek 《Journal of the European Ceramic Society》2009,29(15):3265-3271
The electrical and microstructural characteristics of 1 kΩ/sq. thick-film NTC thermistors (4993, EMCA Remex) fired either on LTCC (low-temperature cofired ceramic) substrates or buried within LTCC structures were evaluated. The thermistors were fired at different temperatures to study the influence of firing temperature on the electrical characteristics. The results were compared with the characteristics obtained on alumina substrates. The sheet resistivities were higher than the resistivities of thick-film thermistors on alumina substrates. The increase of the sheet resistivities was attributed to the diffusion of the glass phase from the rather glassy LTCC substrates into the NTC thermistors. This was confirmed by EDS analyses. However, the increase in the resistivity was linked to an increase of the beta factors. Therefore, the results show that the evaluated NTC thermistors on LTCC substrates can be used for temperature sensors in MCM-Cs as well as in MEMS LTCC structures. When the thermistors were buried in the LTCC substrates, the LTCC structures delaminated during firing, leading to high sheet resistivities and high noise indices. This delamination is attributed to the different sintering rates of the NTC and LTCC materials. 相似文献
200.