• Bulletin of the Korean Chemical Society
• /
• v.34 no.7
• /
• pp.1995-2000
• /
• 2013

Layered $Li_{1.2}(Fe_{0.16}Mn_{0.32}Ni_{0.32})O_2$ was prepared by the mixed hydroxide method at various temperatures. Xray diffraction (XRD) pattern shows that this material has a ${\alpha}-NaFeO_2$ layered structure with $R{\bar{3}}m$ space group and that cation mixing is reduced with increasing synthesis temperature. Scanning electron microscopy (SEM) reveals that nano-sized $Li_{1.2}(Fe_{0.16}Mn_{0.32}Ni_{0.32})O_2$ powder has uniform particle size distribution. X-ray absorption near edge structure (XANES) analysis is used to study the local electronic structure changes around the Mn, Fe, and Ni atoms in this material. The sample prepared at $700^{\circ}C$ delivers the highest discharge capacity of 207 $mAhg^{-1}$ between 2-4.5 V at 0.1 $mAcm^{-2}$ with good capacity retention of 80% after 20 cycles.

• Korean Journal of Materials Research
• /
• v.9 no.1
• /
• pp.57-64
• /
• 1999

The electrical conductivity of TiO$_2$ doped with 0.05~1.5mol% WO$_3$ was measured in the oxygen partial pressure range of 10\ulcorner~10\ulcorner atm and temperature range of 1100~130$0^{\circ}C$ to investigate the defect types and the electrical properties. The grain size and density were increased as the liquid phase was formed by the doped WO$_3$. The secondary phase and WO$_3$peaks at the sample doped up to 4.0 mol% were not detected from the XRD results. The data(log$\sigma$/logPo$_2$) over 110$0^{\circ}C$ were divided into the four regions. From these experimental results, we proposed the following defect regions. 1) Magneli phase(extended defect), 2) Reduced rutile region which is similar to the behavior of undoped rutile, 3) Nearly stoichiometric Ti\ulcornerW\ulcornerO$_2$region in which extra charge of W\ulcorner cation is expected to be compensated by an electron, 4) Overstoichiometric Ti\ulcornerW\ulcornerO\ulcorner region which is a metal deficiency not to be observed in pure TiO$_2$. The electrical conductivity of w-doped TiO$_2$ was influenced by the measuring temperature, oxygen partial pressure, and the dopig content.

• The Journal of the Korean Society for Microbiology
• /
• v.6 no.1
• /
• pp.41-60
• /
• 1971

The author prepared a tuberculin sample using synthetic medium for the test material in this experiment. For the test animals, guinea pigs, healthy calf sensitized with heat killed tubercle bacilli, naturally infected dairy cattle, goat, and calf were used. A reduced reactivity to tuberculin was observed when the second tuberculin test was done within 28 days after the first. The results obtained are summarized as follows. 1. The experimental HCSM tuberculin was shown the similar activities as the control products of standard tuberculin. 2. The potency of the experimental tuberculin preserved at $5^{\circ}C$ in refrigerator maintained the activity for three years. 3. By the intradermal test, the experimental tuberculin was proved to be specific to detect tuberculous dairy cattles and goats. 4. The appearance of skin reaction to tuberculin in naturally infected dairy cattles, goat and beef cattles was soft and diffuse swellings or circumscribed swellings accompanied by induration. 5. In the case of observing tuberculous dairy cattles, goats and beef cattles, as the criterion of the reaction to the caudal fold test, results were taken as positive when findings are either hard and circumscribed or soft and diffuse swellings of 3 mm at least in size. 6. The acid fast organisms isolated from tuberculin positive animals were identified mostly as M. tuberculosis var. bovis. 7. When the tuberculin test was repeated in the tuberculin positive animals, the reactivity decreased rapidly, lasting 4 weeks at least.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.15 no.3
• /
• pp.269-274
• /
• 2002

(Sm/Y)-Ba-Cu-O system high Tc composite superconductors with/without $CeO_2$ additive were directionally grown by zone-melting process, haying large temperature gradient, In air atmosphere. Cylindrical green rods of $({Sm/y})_{1.8}Ba_{2.4}Cu_{3.4}O_x$ [(Sm/Y)1.8] composite oxides by cold isostatic pressing(CIP) method using rubber mold were fabricated. The microstructure and superconducting properties were investigated by XRD, SEM, TEM and SQUID magnetometer. The size of nonsuperconducting $({Sm/y})_2BaCuO_5$ inclusions of the melt-textured (Sm/Y)1.8 sample with CeO$_2$ additive were remarkably reduced and uniformly distributed within the superconducting (Sm/Y)1.8 matrix. Both samples, with/without $CeO_2$ additive, showed an onset Tc $\geq$ 90 K and sharp superconducting transition. The critical current density Jc value of the $CeO_2$ addictive were $1{\times}10^5A/\textrm{cm}^2$ in 77 K, 0 Tesla.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.2 no.4
• /
• pp.199-202
• /
• 2007

In this paper, we examined the operating principle of a passive tag antenna for RFID system in UHF band. Based on the study, we proposed a novel RFID tag antenna which adopts the inductively coupled feeding structure to match antenna impedance to a capacitively loaded commercial tag chip. The proposed tag antenna consists of microstrip lines on a thin PET substrate for low-cost fabrication. The detail structure of the tag antenna were optimized using a full electromagnetic wave simulator of IE3D in conjunction with a Pareto genetic algorithm, and the size of the tag antenna can be reduced up to kr=0.27(2 cm2). We built some sample antennas and measured the antenna characteristics such as a return loss, an efficiency, and radiation patterns. The readable range of the tag antenna with a commercial RFID system showed about 1 to 3 m.

• Korean journal of food and cookery science
• /
• v.22 no.3 s.93
• /
• pp.386-395
• /
• 2006

The purpose of this study was to examine the perceptions and attitudes held by dietitians on seasoned processed meats. The questionnaires were distributed to x (Ed- give the sample size) dietitians at business foodservice operations in Kyungnam province. According to survey, 37.5% of the dietitians answered that it is 'very necessary' to develop seasoned processed meat products. Regarding desired product characteristics, the dietitians were asked about reduced additive use, good hygienic quality, nutritious and healthy quality, low salt content and adequate supply of nutritional information. Over half of the dietitians (59.2%) preferred Korean style seasoned processed meats. The cooking types of Korean seasoned processed meats chosen as new developments were steamed (21.3%), roasted (20.6%) and pilled (18.1%), while the expected frequencies of product usage were in the order of grilled (18.8%), roasted (15.6%), and fried (14.4%). The dietitians wanted no or only little increase in the price compared to current commercial products, units packed in 1 or 3kg sizes and a shelf life under refrigerated or frozen storage of 3-7 days. A minority of the dietitians (40.6%) responded positively to buy the seasoned processed meats if the products meet their needs.

• Journal of the Korean Ceramic Society
• /
• v.42 no.2 s.273
• /
• pp.127-131
• /
• 2005

We examined the effect of low temperature heat-treatment on the optical properties of the photonic crystals self-assembled using a monodispersed spherical $SiO_2$ nanoparticle. When the heat treatment temperature increased, the reflectance peak, which is induced by the photonic band gap, moved to a shorter wavelength direction, and the peak intensity of Fabry-Perot fringes also increased. The highest reflectance peak intensity was obtained in the sample heat-treated at $250\~300^{\circ}C$. The heat-treatment reduced the average particle size and the quantity of defects, and increased the packing density of the photonic crystal.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.29 no.2
• /
• pp.110-113
• /
• 2016

(YNdSm)-Ba-Cu-O system high Tc composite superconductors were directionally grown by zone melting process, having large temperature gradient, in air atmosphere. Cylindrical green rods of $(YNdSm)_{1.8}Ba_{2.4}Cu_{3.4}O_x$ [(YNS)1.8]composite oxides by CIP (cold isostatic pressing) method using rubber mold were fabricated. The microstructure and superconducting properties were investigated by XRD, TEM and SQUID magnetometer. The size of nonsuperconducting $(YNdSm)_2BaCuO_5$ inclusions of the melt-textured (YNS)1.8 sample with $CeO_2$ additive were remarkably reduced and uniformly distributed within the superconducting (YNS)1.8 matrix. (YNS)1.8 samples, with / without $CeO_2$ additive, showed an onset $T_c{\geq}90K$ and sharp superconducting transition. The critical current density $J_c$ value of the (YNdSm)1.8 superconductor with $CeO_2$ additive were 840 A, $1.2{\times}104A/cm^2$ in 77 K, 0 Tesla by direct current transport method.

• Journal of the Korean Ceramic Society
• /
• v.12 no.1
• /
• pp.16-22
• /
• 1975

The network structure of a glass is known to be cracked by a chemical reaction, diffusion, and ion exchange of alkali ion, formed at the crack tip of the glass surface, when water is present on the glass surface. Since the durability of glass is reduced, due to the fatigue phenomenon mentioned above, pollution problem of glass goods, especially bottle glass, is becoming acute gradually. A static fatigue phenomenon was studied thermodynamically in this paper, and a mechanism of static fatigue, a quality control, and a method of preventing pollution for the main local glass goods were also investigated. The PH of reacted solution and the quantity of extracted alkali were measured at different conditions such as temperature, reacting time, particle size of a crushed glass sample, and the nature of reacting solution. The enthalpy change was calculated from the Arrhenius equation. The results are given below; 1) The absolute value of enthalpy change for the bottle glass was found to be higher than the for the flat glass. 2) The fatigue phenomenon of a glass was more sensitive to the temperature than to the reacting time. 3) The durability of glass in acid solution is stronger than in alkaline solution. 4) The substance which cracks the network structure of glas is considered the hydroxyl ion.

• Journal of Microbiology
• /
• v.35 no.3
• /
• pp.206-212
• /
• 1997

Heliobacillus mobilis is a strictly anaerobic Gram-positive bacterium which contains a primitive Photosystem I-type reaction center. The membrane-bound cytochrome $C_{553}$ from the heliobacterium suggested to be the immediate electron donor to the photooxidized pigment (P798+) has been isolated and characterized. The heme protein was visualized as a major component with an apparent molecular size of 17kDa in TMBZ-staining analysis of the membrane preparation and showed characteristic $\alpha$ (552.5 nm), $\beta$ (522nm), and Soret absorption (416 nm) peaks of a typical reduced c-type cytochrome in the partially purified sample. The internal 43 amino acid sequence of the electron donor was obtained by chemical agent and protease treatments followed by N-terminal sequencing of the resulting fragments. The internal sequence carries lots of lysine residues and a Cys-X-X-Cys-His sequence motif which are the characteristics of typical c-type cytochromes. The analysis of the sequence by FAST or FASTA program, however, did not show any significant similarity to other known heme proteins.