• Title, Summary, Keyword: structural characterization

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Tensile and fracture characterization using a simplified digital image correlation test set-up

  • Kumar, Abhishek;Vishnuvardhan, S.;Murthy, A. Ramachandra;Raghava, G.
    • Structural Engineering and Mechanics
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    • v.69 no.4
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    • pp.467-477
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    • 2019
  • Digital image correlation (DIC) is now a popular and extensively used full-field metrology technique. In general, DIC is performed by using a turnkey solution offered by various manufacturers of DIC. In this paper, a simple and economical set-up for DIC is proposed which uses easily accessible digital single-lens reflex (DSLR) camera rather than industrial couple-charged device (CCD) cameras. The paper gives a description of aspects of carrying a DIC experiment which includes experimental set-up, specimen preparation, image acquisition and analysis. The details provided here will be helpful to carry DIC experiments without specialized DIC testing rig. To validate the responses obtained from proposed DIC set-up, tension and fatigue tests on specimens made of IS 2062 Gr. E300 steel are determined. Tensile parameters for a flat specimen and stress intensity factor for an eccentrically-loaded single edge notch tension specimen are evaluated from results of DIC experiment. Results obtained from proposed DIC experiments are compared with those obtained from conventional methods and are found to be in close agreement. It is also noted that the high resolution of DSLR allows the use of proposed approach for fracture characterization which could not be carried out with a typical turnkey DIC solution employing a camera of 2MP resolution.

Structural characterization of aluminum oxide precipitation formed on the surface of nickel-carbon film (니켈/탄소 복합체 박막 표면에 형성된 알루미늄 산화물의 구조 분석)

  • Lee, Min-Hui;Na, Hyeon-Ung;Choe, Han-Sin;Kim, Gyu-Hyeon
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • pp.174-175
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    • 2014
  • We fabricated a Ni/C composite thick film on ${\alpha}-Al_2O_3$ substrate. A number of precipitations were observed on the film surface. Structural characterization was performed on the observed precipitations using transmission electron microscopy (TEM) with help of the elemental mapping, electron diffraction (ED) and ED simulation. The structural characterization revealed that the precipitation is ${\theta}-Al_2O_3$ having the space group of C2/m (Monoclinic).

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Structural Characterization and EDLC-Electrode Performance of Coal-Tar-Pitch Activated Carbon Using K2CO3 Treatment (K2CO3 처리된 Coal Tar Pitch 활성탄 전극의 결정성 및 EDLC 성능)

  • Choi, Poo Reum;Jung, Ji Chul;Lim, Yun-Soo;Kim, Myung-Soo
    • Korean Journal of Materials Research
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    • v.26 no.9
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    • pp.460-467
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    • 2016
  • Activated carbons (ACs) have been used as EDLC (electric double-layer capacitor) electrode materials due to their high specific area, stability, and ecological advantages. In order to prepare ACs with high density and crystallinity, coal tar pitch (CTP) was activated by $K_2CO_3$ and the textural and electrochemical properties of the obtained ACs were investigated. Although the CTP ACs formed by $K_2CO_3$ activation had much smaller specific surface area and pore volume than did the CTP ACs formed by KOH activation, their volumetric specific capacitance (F/cc) levels as electrode materials for EDLC were comparable due to their higher density and micro-crystallinity. Structural characterization and EDLC-electrode performance were studied with different activation conditions of $CTP/K_2CO_3$ ratio, activation temperature, and activation period.

Isolation and Structural Characterization of an Oligosaccharide Produced by Bacillus subtilis in a Maltose-Containing Medium

  • Shin, Kwang-Soon
    • Preventive Nutrition and Food Science
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    • v.21 no.2
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    • pp.124-131
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    • 2016
  • Among 116 bacterial strains isolated from Korean fermented foods, one strain (SS-76) was selected for producing new oligosaccharides in a basal medium containing maltose as the sole source of carbon. Upon morphological characterization using scanning electron microscopy, the cells of strain SS-76 appeared rod-shaped; subsequent 16S rRNA gene sequence analysis revealed that strain SS-76 was phylogenetically close to Bacillus subtilis. The main oligosaccharide fraction B extracted from the culture supernatant of B. subtilis SS-76 was purified by high performance liquid chromatography. Subsequent structural analysis revealed that this oligosaccharide consisted only of glucose, and methylation analysis indicated similar proportions of glucopyranosides in the 6-linkage, 4-linkage, and non-reducing terminal positions. Matrix-assisted laser-induced/ionization time-of-flight/mass spectrometry and electrospray ionization-based liquid chromatography-mass spectrometry/mass spectrometry analyses suggested that this oligosaccharide consisted of a trisaccharide unit with 1,6- and 1,4-glycosidic linkages. The anomeric signals in the $^1H$-nuclear magnetic resonance spectrum corresponded to ${\alpha}$-anomeric configurations, and the trisaccharide was finally identified as panose (${\alpha}$-D-glucopyranosyl-1,6-${\alpha}$-D-glucopyranosyl-1,4-D-glucose). These results suggest that B. subtilis SS-76 converts maltose into panose; strain SS-76 may thus find industrial application in the production of panose.

CHARACTERIZATION THEOREMS FOR CERTAIN CLASSES OF INFINITE GRAPHS

  • Jung, Hwan-Ok
    • Journal of applied mathematics & informatics
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    • v.30 no.1_2
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    • pp.245-252
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    • 2012
  • In this paper we present a necessary and sufficient conditions for an infinite VAP-free plane graph to be a 3LV-graph as well as an LV-graph. We also introduce and investigate the concept of the order and the kernel of an infinite connected graph containing no one-way infinite path.

Structural Characterization of Branched Polyesters Using TOF-SIMS Combined with Transesterification

  • Lee, Yeonhee;Seunghee Han;Yoon, Jung-Hyeon;Hyuneui Lim;Moojin Suh
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.203-203
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    • 1999
  • Mass spectrometry technique provides the molecular weight distribution, data on the sequence of repeat units, polymer additives, and impurities, and structural information. time-of-Flight secondary Ion Mass Spectrometry (TOF-SIMS) has been used for structural characterization of various polymers1-2. the masses of repeat units and terminal groups and molecular weight distributions of polymers have been determined from their TOF-SIMS spectra. TOF-SMIS provides good sensitivity and structural specificity for high mass ions so that intact oligomers and large polymer fragments are observed. In this study, we investigated the detailed structural information on the oligomers and fragment ions of branched poly(1,3-butylene adipate) and branched poly[di(ethylene glycol) adipate] and the transesterification products of branched polyesters with trifluoroacetic acid or chloro difluoroacetic acid. Branched polyesters were chosen because they are important polymers but difficult to characterize; thus branched polyesters provide challanging test for TOF-SIMS. TOF-SIMS spectra of polyesters are obtained from thin polymer films cast from solution on a silver substrate. A good solvent for a polumer solution disrupts intermolecular forces between polymer chains but leaves the polumer intact. Transesterification reactions are potentially useful for characterization of high molecular weight and intractable polyesters. Transesterification products of polyesters and trifluoroacetic acid or an integral number of polyester repeat units and an additional diol. The progress of such reactions was monitored using peak intensities of reactants and products in TOF-SIMS spectra. The increasing abundance of tagged ions indicates that the reaction has progressed with time.

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