Time filter

Source Type

Seoul, South Korea

Stable and uniform electron field emitters were fabricated by the screen-printing of a carbon nanotube (CNT) paste. The CNT paste was prepared by mixing thin multi-walled CNTs, organic binder and glass frits in terpineol followed by three-roll milling. The paste was screen-printed onto an indium tin oxide (ITO)-coated glass substrate and exposed to firing. The emitters formed by the adhesive tape treatment of the printed pastes generally showed non-uniform heights of emitting tips due to the large-sized glass frit distributed in the paste. On the other hand, small glass frits with a uniform particle size distribution could be obtained by high energy milling. In addition, the CNT paste prepared using the high energymilled glass frits showed very uniform tip heights. The uniform CNT tip height was found to play an important role in acquiring the long-term emission stability and uniformity of field emitters. © 2013 Elsevier B.V. All rights reserved. Source

Sikora M.,Silesian University of Technology | Sikora M.,Randnter
Expert Systems with Applications

The paper presents results of application of a rule induction and pruning algorithm for classification of a microseismic hazard sate in coal mines. Due to imbalanced distribution of examples describing states "hazardous" and "safe", the special algorithm was used for induction and rule pruning. The algorithm selects optimal parameters' values influencing rule induction and pruning based on training and tuning sets. A rule quality measure which decides about a form and classification abilities of rules that are induced is the basic parameter of the algorithm. The specificity and sensitivity of a classifier were used to evaluate its quality. Conducted tests show that the admitted method of rules induction and classifier's quality evaluation enables to get better results of classification of microseismic hazards than by methods currently used in mining practice. Results obtained by the rules-based classifier were also compared with results got by a decision tree induction algorithm and by a neuro-fuzzy system. © 2010 Elsevier Ltd. All rights reserved. Source

Girijashankar V.,Randnter
Physiology and Molecular Biology of Plants

An efficient in vitro regeneration protocol enables mass multiplication, genetic modification and germplasm conservation of desired plants. In vitro plant regeneration was achieved from nodal segments of 18-months-old superior genotypes of Eucalyptus camaldulensis trees through direct organogenesis (DO) and direct somatic embryogenesis (DSE) pathways. Initial bud break (BB) stage occurred via DO while shoot multiplication phase followed both DO and DSE pathways. Interestingly, both BB and shoot multiplication stages were achieved on shoot induction and multiplication (SIM) media composed of Murashige and Skoog (MS) basal medium supplemented with 2 mg l -1 benzyl aminopurine (BAP) and 0. 1 mg l -1 naphthalene acetic acid (NAA). Best shoot elongation response was observed on half strength MS fortified with 0. 5 mg l -1 BAP, while root induction and elongation was superior in 1/2 MS + 1 mg l -1 Indole butyric acid (IBA). Full strength MS fortified with cytokinins (BAP) and weak auxin (NAA) in the ratio of 20:1 favored direct regeneration pathways. Further, half strength MS supported shoot and root development. The absence of intervening callus phase in this protocol can help in minimizing the chance occurrence of somaclones. When compared to other compositions tried, hardening in 100 % coco peat resulted in maximum survival (80 %) of the in vitro raised plantlets. For mass multiplication, fortnight subculturing of a single nodal explants for eight passages on SIM medium resulted in 60-148 shoot initials. Repeated subculturing in SIM medium induced the formation of direct somatic embryos which in turn improved the turnover capacity and enabled large scale clonal multiplication of elite and desirable trees of E. camaldulensis. Following this protocol, it takes a minimum time period of four-months between in vitro explant inoculation to hardening stage. In the present study, DO and DSE pathway of plant regeneration was reported occurring simultaneously in the same nodal explants of E. camaldulensis. © 2011 Prof. H.S. Srivastava Foundation for Science and Society. Source

Nordstrom B.,Randnter
Nordic Pulp and Paper Research Journal

Compression strength represents one of the most important properties for linerboard. Knowledge promoting efficient selection and utilization of the fiber raw material is of key importance, as the furnish cost is a major component of the production cost. Nevertheless, the effect of fiber dimensions on compression strength was found to be unclear in the literature. This investigation examines effects of fiber length and fiber cross-sectional dimensions on compression strength for handsheets over a density range from 600 to 900 kg/m3, with the density varied by the wet-pressing pressure. Two pulps with different fiber length distributions (1.5 vs. 2.4 mm in length-weighted average) but with otherwise similar fiber characteristics were prepared from the same original softwood kraft pulp. The fiber length was found to have no effect on compression strength at a given density. The effect of cross-sectional fiber dimensions was investigated using four softwood pulps whose cross-sectional dimensions covered a substantial range. It was found that the fiber cross-sectional dimensions had no appreciable effect on compression strength at a given density. Contrary to earlier belief, this result suggests that buckling of free fiber segments between bonds is not a controlling factor for compression strength at densities from 600 kg/m3 and above. © 2014, SPCI. All rights reserved. Source

Jeong M.S.,Sungkyunkwan University | Han J.H.,Chonnam National University | Choi Y.C.,Randnter

Single-walled carbon nanotubes (SWCNTs) were synthesized by arc discharge and then purified by a two-step process including thermal and acid treatments. As-synthesized, thermal-treated, and fully purified (thermal- and acid-treated) samples were characterized using thermogravimetric analysis, continuous resonant Raman scattering, and ultraviolet-visible-near infrared (UV-Vis-NIR) absorption spectroscopy. Thermal and acid treatments eliminate carbonaceous particles and metal catalyst particles, respectively, resulting in high-purity SWCNTs. Continuous resonant Raman scattering and UV-Vis-NIR absorption spectroscopy demonstrated that the metallic content of the arc-synthesized SWCNTs varied according to the purification process; as-synthesized (∼15%), thermal-treated (∼30%), and thermal/acid-treated (∼25%). Transparent conducting films were prepared using three different purity grades and their properties were analyzed. Thermal-treated nanotubes displayed superior performance compared with the other samples owing to its higher metallic content and smaller bundle diameters. © 2013 Elsevier Ltd. All rights reserved. Source

Discover hidden collaborations