PL
 |
EN
Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl
Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 13

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
1
Content available Microstructure and Corrosion Behaviors of Biodegradable Mg-1Zn-1Zr-xSn Alloys Prepared by Powder-In-Tube Rolling
100%
Zakiyuddin A. , Lee K.
Archives of Metallurgy and Materials
|
2018
|
tom Vol. 63, iss. 3
1467--1471
EN
The objective of the present study was to investigate the effects of Sn addition on the mechanical and corrosion properties of Mg-1Zn-1Zr-xSn (x = 1, 2, 3, 4, 5 wt.%) alloys prepared by powder-in-tube rolling (PTR) method. The PTR-treated Mg alloys reached 98.3% of theoretical density. The hardness of the alloy increased with Sn addition. Two main intermetallic phases, Mg2Sn and Zn2Zr3, were formed in the alloys. The Mg2Sn intermetallic particles were observed along the grain boundaries, while the Zn2Zr3 particles were distributed in the Mg matrix. The addition of 1 wt. % Sn caused the corrosion potential to shift toward a more positive value, and the resulting alloy exhibited low corrosion current density.
2
Content available Large-Area Sodium Titanate Nanorods Formed On Titanium Surface Via NaOH Alkali Treatment
100%
Lee K. , Yoo D.
Archives of Metallurgy and Materials
|
2015
|
tom Vol. 60, iss. 2B
1371--1374
EN
Ti surfaces covered with large sodium titanate nanorods act as efficient electrodes for energy conversion and environmental applications. In this study, sodium titanate nanorod films were prepared on a Ti substrate in a 5M NaOH aqueous solution followed by heat treatment. The morphological characterization and the crystal structures of the sodium titanate nanorods were investigated via scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS). Thin amorphous sodium titanate layers formed during the alkali-treatment, and sodium titanate nanorods were obtained after heat treatment at a temperature of 700°C. The sodium titanate nanorods obtained at this temperature had a thickness of about 80 nm and a length of 1 μm. The crystal structure of the sodium titanate was identified with the use of Na2Ti5O11. The nanorods were agglomerated at a temperature above 900°C, and large-scale nanorods formed on the Ti surface, which may be used for electrodes for energy conversion applications.
3
Content available RF Magnetron Sputtering Coating Of Hydroxyapatite On Alkali Solution Treated Titanate Nanorods
100%
Lee K. , Shin G.
Archives of Metallurgy and Materials
|
2015
|
tom Vol. 60, iss. 2B
1319--1322
EN
Hydroxyapatite (HA) is a material with outstanding biocompatibility. It is chemically similar to natural bone tissue, and has therefore been favored for use as a coating material for dental and orthopedic implants. In this study, RF magnetron sputtering was applied for HA coating. And Alkali treatment was performed in a 5 M NaOH solution at 60°C. The coated HA thin film was heat-treated at a range of temperatures from 300 to 600°C. The morphological characterization and crystal structures of the coated specimens were then obtained via FE-SEM, XRD, and FT-IR. The amorphous thin film obtained on hydrothermally treated nanorods transformed into a crystalline thin film after the heat treatment. The change in the phase transformation, with an enhanced crystallinity, showed a reduced wettability. The hydrothermally treated nanorods with an amorphous thin film, on the other hand, showed an outstanding wettability. The HA thin film perpendicularly coated the nanorods in the upper and inner parts via RF magnetron sputtering, and the FT-IR results confirmed that the molecular bonding of the coated film had an HA structure.
4
Content available Analysis of checklists for agricultural safety management
80%
Kim H. , Rasanen K. , Chae H. , Lee K.
Annals of Agricultural and Environmental Medicine
|
2018
|
tom 25
|
nr 3
5
Content available Hearing impairment among Korean farmers, based on a 3-year audiometry examination
80%
Lee S. , Lee K. , Lee S.-J.
|
|
nr 1
6
Expression profile analysis of human peripheral blood mononuclear cells in response to aspirin
80%
Choi S. , Park H. S. , Cheon M. S. , Lee K.
|
2005
|
tom 53
|
nr 2
7
Reconstruction of postglacial paleoproductivity in Long Lake, King George Island, West Antarctica
71%
Yoon H. , Khim B. , Lee K. , Park Y. , Yoo K.
Polish Polar Research
|
2006
|
tom 27
|
nr 3
189-206
EN
A sediment core (LS-1) collected from Long Lake in King George Island, South Shetland Islands (West Antarctica) was analyzed for a variety of textural, geochemical, iso- topic and paleontological properties together with 14C age dates. These data combined with published records of other studies provide a detailed history of local/regional postglacial paleoproductivity variation with respect to terrestrial paleoclimate change. The lithologic contrast of a lower diamicton and an upper fine-grained sediment demonstrates glacial recession and subsequent lake formation. The upper fine-grained deposit, intercalated by mid-Holocene tephra-fallout followed by a tephra gravity flow, was formed in a lacustrine environment. Low total organic carbon (TOC) and biogenic silica (Sibio) contents with high C/N ratios characterize the diamicton, whereas an increase of TOC and Sibio contents characterize the postglacial lacustrine fine-grained sediments, which are dated at c. 4000 yrBP. More notable are the distinct TOC maxima, which may imply enhanced primary productivity during warm periods. Changes in Sibio content and S13C values, which support the increasing paleoproductivity, are in sympathy with these organic matter variations. The uniform and low TOC contents that are decoupled by Sibio contents are attributed to the tephra gravity flows during the evolution of the lake rather than a reduced paleoproductivity. A very recent TOC maximum is also characterized by high Sibio content and S13C values, clearly indicating increased paleoproductivity consequent upon gradual warming across King George Island. Comparable with changes in sediment geochemistry, the occurrence and abundance of several diatom species corroborate the paleoproductivity variations together with the lithologic development. However, the paleoclimatic signature in local terrestrial lake environment during the postglacial period (for example the Long Lake) seems to be less distinct, as compared to the marine environment.
8
Content available Enhanced Microwave Absorption of CNT Composites Mixing with Fe3O4 and Carbonyl Iron
61%
Park J. H. , Choi J. , Lee K. , Park J. , Song J. K. , Jeon E.
Archives of Metallurgy and Materials
|
2018
|
tom Vol. 63, iss. 3
1513--1516
EN
We fabricated two different kinds of composite materials for absorbing microwave in a frequency range of 2 to 18 GHz using coaxial airline and thru-reflect-line (TRL) method. The composite materials having carbon nanotube (CNT) with carbonyl iron (CI) or iron oxide (Fe3 O4 ) were fabricated by mixing each components. Magnetic properties were measured by SQUID equipment. Complex permittivity and complex permeability were also obtained by measuring S-parameters of the toroidal specimen dispersing CI/CNT and Fe3 O4 /CNT into the 50 weight percent (wt%) epoxy resin. The real permittivity was improved by mixing the CNT however, the real permeability was same as pure magnetic powders. The CI/CNT had a maximum value of real permittivity and real permeability, 11 and 1.4 at 10 GHz, respectively. The CNT composites can be adapted to the radar absorbing materials, band width 8-12 GHz.
9
Content available Development of a large beam facility
61%
Oh B. , In S. , Lee K. , Jeong S. , Seo C. , Chang D.
|
2006
|
tom Vol. 51, nr 1
37-42
EN
A large beam facility for the application of high power ion beams has been developed at the Korea Atomic Energy Research Institute (KAERI). The primary usage of this facility is to develop an 8 MW neutral beam heating system for a tokamak, but other applications using a large beam would also be possible in the near future. The facility is composed of a bucket ion source (120 kV, 65 A), related beam line components including a large vacuum chamber (3 m x 4 m x 5 m), power supplies for the ion source, control and DAS (Data Acquisition System), beam diagnostics system, and a water circulation system (2 MW) for cooling of the beam line components. The maximum beam parameters at present are a beam energy of 87 kV and a beam current of 17.5 A with a beam size of 13 x 45 cm2. A maximum pulse length of 10 s could be achieved with a 1 MW beam power. The beam power with a hydrogen ion will be increased up to 7.5 MW during 5 s.
10
Content available Effect of Alloying Elements on Plastic Workability and Corrosion Behavior of Ti-X (X = 6 Co, 8 Cr, 4 Fe, 6 Mn, 10 Mo, and 36 Nb) Binary Alloys
60%
Zhao Z. , Lee K.
|
11
Effect of variants in the ovine skeletal-muscle-specific calpain gene on body weight
51%
Chun H. , Choi B. , Jang G. , Lee K. , Kim H. , Yoon S. , Im S. , Davies M. , Hines H.
|
2007
|
tom 48
|
nr 1
63-68
EN
The ovine skeletal-muscle-specific calpain gene (p94), which is known also as the n-calpain or calpain 3 gene (CAPN3), was screened with primers. Selection of the PCR primers was based on the ovine cDNA sequence (GenBank accession No. AF087570). After sequence alignment between the ovine and human (AY902237) genes, exon and intron boundaries were determined. Polymorphisms were observed in the intron region for the CAPN31112 and CAPN31213 segments, and the sequences for these segments were submitted to the GenBank (AF309635 and AY102617, respectively). Body weight was recorded at birth, weaning and post-weaning. Calpain 3 genotypes of the CAPN31112 segment were associated with birth weight (P < 0.01), and a dominant gene effect was observed. Breeding group, birth type, and rearing type were significantly associated with weight traits. Allele frequencies were similar in purebred and crossbred animals.
12
Content available Compressive Deformation Behavior of Thick Micro-Alloyed HSLA Steel Plates at Elevated Temperatures
41%
Lee J.-H. , Lee K. , Kim D.-O.
|
13
Content available Large-Area Sodium Titanate Nanorods Formed On Titanium Surface Via NaOH Alkali Treatment
36%
Lee K. , Yoo D.
|
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.