• Animal cells and systems
• /
• v.6 no.3
• /
• pp.215-219
• /
• 2002

In mid-April, 2000, hundreds of thousands of fish floated dead on the Chungnang River, one of the small branches of the Han River in Seoul. We examined the causes of the accident in detail, through analysis of monitorinq data from the Han River Monitoring Project, which employed the transplanted aquatic moss, Fontinalis antipyretica. This allowed investigation of another possible cause of the fish kill: release of trace metals into the river from industrial sources during the rainfall event. In addition, we aimed to verify the usefulness of aquatic mosses as bioindicators of the event. Water samples collected 48 h after the fish kill exhibited low pH and high Total-N and Total-p, indicating that acidic compounds rich in nitrogen and phosphorus might be a major contaminant. BOD and COD were also very high. On the whole, the conditions of the river water were degraded at that time. Distinct trends were not observed in the chlorophyll phaeophy-tinization quotient and photosynthesis rate of transplanted mosses. How-ever mosses sampled soon after the accident exhibited the lowest values for those variables (P < 0.01), suggesting that stress factors in the river were diluted out over time. Heavy metals with characteristics of industrial effluents (Cr, Pb, Zn, Fe, Cu, and Cd) increased (p ＜ 0.01), indicating that they were unlikely to be major causes of the accident.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2004.08a
• /
• pp.220-222
• /
• 2004

Feasibility of BaO-ZnO-$B_2O_3$ (BZB) based glass system in the light of dielectric and thermal expansion properties are reported in the literature. Effects of addition of various types of ceramic fillers to the BZB-based glass on the thermochemical stability and mechanical properties were investigated in the present work. The studied filler-glass system demonstrated a capability to host various types of ceramic fillers to form thermochemically stable microcomposites at the processing temperature suitable for PDP systems. At the same time, mechanical strength of the filler-glass composites was much improved as compared to the glass itself These observations brighten the feasibility of the Pb-free BZB-based glass system as a host to employ various types of crystalline ceramic fillers so that it can be applied to barrier rib material in plasma display panels.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.11 no.11
• /
• pp.1014-1021
• /
• 1998

We evaluated the effect of processing variables on microstructural evolution interface irregularity between Ag sheath and superconductor core and resultant critical current density(J$_{c}$) of (Bi,Pb)$_2$Sr$_2$Ca$_2$Cu$_3$O$_{x}$(2223) superconductor tape. The value of J$_{c}$ was significantly influenced by the interface irregularity, degree of texturing and relative 2223 content. The interface became more irregular(sausage effect), while the degree of texturing gradually improved as the dimension of tape decreased during forming process. As the dimension of wire/tape were changed from diameter of 3.25 mm to thickness of 0.20 mm, J$_{c}$ value was observed to be increased by 10 times. In addition, optimum sintering temperature for improved J$_{c}$ was observed to be 835$^{\circ}C$ in a ambient atmosphere probably due to combined effect of both improved texturing and high 2223 content. Microstructural investigation showed the degree of texturing was degraded by the existence of both second phases and interface irregularity. It was observed that larger grain size and better texturing was developed near relatively flat interface compared to those inside superconducting core.ting core.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.52 no.4
• /
• pp.153-158
• /
• 2003

This thesis deal with ferroelectric and ferromagnetic materials. PZT/Ferrite ceramics were made by the making process using PZT powder and garnet ferrite powder. PZT and ferrite are mixed as much 90%-10%, 50%-50%, and so on. After making samples, we are polishing samples until thickness is 0.1~0.2mm. We measured all kinds of samples in room temperature and applied magnetic field from -4500 to 4500 Oersted and conducted test of magnetical and electrical measurement using VSM and lpC resolution electrometer calibrated with RT66A pulsed tester. From this measurement, we can calculate tunability of these samples using C value obtained from P-E loop. As a result, it was able to measure magnetic characteristic when two matter had each other component ratio, and it was compound. However, it confirmed the possibility that was able to have ferroelectric characteristic with you in PZT 90% and ferrite 10%. Therefore, If this thing comes for PZT 50% and ferrite 50% have ferroelectric characteristic as him in a compound sample ore, can use this in an oscillator, supersonic waves detector in addition to a piezoelectric element. It may contribute to multipurpose of an element and demands such as a miniaturization of equipment, efficiency, reduce of a price which can use a characteristic of two components.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.34 no.3
• /
• pp.508-517
• /
• 2010

One-step reduction/dyeing method was optimized for wool dyeing with natural indigo dye in this study. The effects of reduction/dyeing conditions including dye temperature and time, the pH of bath, concentration of dye, and reducing agent on dye uptake and color were investigated. The dye uptake was higher with no addition of alkali. Dyeing was carried out through the use of only sodium hydrosulfite in the bath. The maximum dye uptake was obtained at $60^{\circ}C$ for 30min and the dyed fabrics appeared in the PB Munsell color range. Dye uptake improved with the increase of a natural indigo dye concentration with the same sodium hydrosulfite concentration. At a higher dye uptake, the fabric color became more purplish and the maximum absorption shifted from 660nm to 620nm. Color reproducibility was reliable with a color difference in the range of 0.41~1.43. Regardless of color strength, washing and dry cleaning fastnesses were good with a 4/5 rating, and fastnesses to rubbing and light were acceptable with a 3/4~4 rating.

• Journal of Sasang Constitutional Medicine
• /
• v.22 no.3
• /
• pp.132-140
• /
• 2010

1. Objective: To compare the contents and transfer rate of hazardous substances in crude, washing solution, crude after washing, decoction and remnant after boiling. 2. Methods: The heavy metal contents of each step were measured by inductively coupled plasma mass spectrometer (ICP-MS) and mercury analyzer (MA-2). In order to analyze pesticides in each sample we used simultaneous multi-residue analysis of pesticides by GC/ECD, which was followed by GC/MSD analysis to confirm the identity of the detected pesticide in each sample. In addition, the contents of sulfur dioxide (SO2) were performed by Monier-Williams distillation method. 3. Results: 1) Contents (mg/kg) of heavy metals in decoction of all herbal medicine prescriptions were not detected. 2) Transfer rates (%) of heavy metals from crude to remnant were As (83.3%), Cd (100.0%), Pb (182.6%) and Hg (100.0%). 3) Contents (mg/kg) of residual pesticides were not detected. 4) Transfer rate (%) of sulfur dioxide (SO2) from crude to remnant was 44.2%. 4. Conclusion: Our results showed that boiled herbal medicine prescriptions which we take is safe from the hazardous substances.

• Journal of Microbiology and Biotechnology
• /
• v.11 no.6
• /
• pp.1031-1037
• /
• 2001

By a sequential action of ${\beta}$-ketothiolase and acetoacetyl-CoA reductase, two molecules of acetyl-CoA re converted into D-3-hydroxybutyryl-CoA, a substrate for PHB synthase to form poly-3-hydroxybutyryl-CoA, a substrate for PHB synthase to form poly-3-hydroxybutyrate (PHB) of rhodobacter sphaeroides. The ${\beta}$-ketothiolase gene, phbA, and acetoacetyl-CoA reductase gene, phbB, were cloned and analyzed for their expression. Enzyme activities of ${\beta}$-ketothiolase and acetoacetyl-CoA reductase showed constitutive levels during aerobic and photoheterotrophic growth of R. sphaeroides. In addition, no difference of each enzyme activity was observed between cells grown aerobically and photoheterotrophically. The constitutive level of the enzyme activities are regulated according to the growth phases along with growth conditions. Thus, phbAB expression is not determinative in regulating the PB content. On the other hand, phbA-deleted cell AZI accumulated only $10\%$ PHB of the wild-type, and an elevated dosage of phbAB in trans in R. sphaeroides resulted in a higher content of PHB, indicating that phbAB codes for the enzymes responsible for providing the main supply of subsyrate for PHB synthase. PHB formation by an alternative pathway that does not does not depend on the phbA-and phbB-coding enzymes is also proposed.

• Journal of Korea Foundry Society
• /
• v.18 no.6
• /
• pp.570-577
• /
• 1998

An investigation has been conducted to describe solidification characteristics in Sn-Zn binary system and Sn-Zn-Ag ternary system added by Ag produced by the continuous casting process using heated mold as a basic study for developing Pb-free solder materials. To obtain the continuous casting rods with mirror surface and near net shape at higher casting speed, water flow rates must be increased and mold temperature must be lowered. However, surface tearing in the casting rods occured at lower continuous casting speed while break out occured at higher continuous casting speed even if optimum conditions such as water flow rate and heated mold temperature are determined. Primary ${\alpha}Sn$ and eutectic structure in unidirectioally solidified Sn-Zn alloys were finer with increased casting speed. But, directionality may not be expected for primary Zn in hypereutectic Sn-Zn alloy. It was found that the addition of $0.2{\sim}0.8%$ Ag promoted the growth of primary ${\alpha}Sn$ dendrites. The changes of tensile strength and elongation in Sn-Zn binary alloys were not observed while the increase of tensile strength and the decrease of elongation in Sn-Zn-Ag ternary alloys were observed with increased casting speed.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.6
• /
• pp.1769-1776
• /
• 2014

Binding modes of a series of catechol derivatives such as protein tyrosine phosphatase 1B (PTP1B) inhibitors were identified by molecular modeling techniques. Docking, molecular dynamics simulations and free energy calculations were employed to determine the modes of these new inhibitors. Binding free energies were calculated by involving different energy components using the Molecular Mechanics-Poisson-Boltzmann Surface Area and Generalized Born Surface Area methods. Relatively larger binding energies were obtained for the catechol derivatives compared to one of the PTP1B inhibitors already in use. The Molecular Mechanics/Generalized Born Surface Area (MM/GBSA) free energy decomposition analysis indicated that the hydroxyl functional groups and biphenyl ring system had favorable interactions with Met258, Tyr46, Gln262 and Phe182 residues of PTP1B. The results of hydrogen bound analysis indicated that catechol derivatives, in addition to hydrogen bonding interactions, Val49, Ile219, Gln266, Asp181 and amino acid residues of PTP1B are responsible for governing the inhibitor potency of the compounds. The information generated from the present study should be useful for the design of more potent PTP1B inhibitors as anti-diabetic agents.

• Progress in Superconductivity and Cryogenics
• /
• v.1 no.2
• /
• pp.1-7
• /
• 1999

we evaluated the effects of joining process such as contact method. shape of joined area and pressure on the electrical and mechanical properties of Bi-2223 superconducting tape, Specifically. the current capacity of the jointed tape was measured as a function of uniaxial pressure. and the thermal shock, bonding strength and the thermal of the tape were evaluated and correlated to the microstructural evolution. It was observed that the current capacity was significanrly dependent on the uniaxial pressure The jointed tape, fabricated with a pressure of 1,000-1,600 Mpa. showed the highest value of current capacity results from improvements in core density, contacting area and grain alignment, ect. In addition, the strength of jointed tape was measured to be 86 Mpa, which is about 88% of the unjoined ape's strength. The irreversible strain($\varepsilon$irrev) for the jointed tape was measured to be 0.1%, smaller than that of unjoined tape ($\varepsilon$irrev= 0.3%). The decrease in the strength and irreversible strain for jointed tape is believed to be due to the irregular geometry/morphology of the transition area of the tape.