• Transactions of Materials Processing
• /
• v.15 no.9 s.90
• /
• pp.660-666
• /
• 2006

This study examined the mechanical properties and bending formability evaluation of spring strip materials(SK5 CSPH, STS 301 CSP-EH, C7701-H). The hardness test and tensile test were performed at room temperature($20^{\circ}C$) for mechanical properties. The U-bending test were carried out at various conditions of punch corner radius(Rp), ratio of punch comer radius/thickness(Rp/t) and ratio of clearance/thickness(Rp/t) and ratio of clearance/thickness(C/t) for bending formability evaluation.

• Journal of Environmental Science International
• /
• v.12 no.3
• /
• pp.287-297
• /
• 2003

To investigate water quality and pollution states of rivers in Gwangju city, total of 30 water samples were taken from the main stream of Yeongsan river, Hwangryong river and Gwangju stream in dry and flood seasons. Physico-chemical characteristics of above streams according to pH-Eh and Piper's diagrams we, typically, assigned to natural river water. In the streams, BOD, COD, T-N and T-P indicating water quality mostly increase toward downstream. Notably, water qualities in area near connection between the Gwangju stream and the main stream of Yeongsan river are polluted over V level in rivers and lakes water quality standard. The pollutions are influenced by lift and agricultural foul waters from Gwangju City and farming areas around upstream branches of the Yeongsan river, reasonably. Besides, heavy metals are below the standard in those streams. So, it is considered that the streams are polluted by not industrial but life/agricultural foul waters.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2000.11a
• /
• pp.262-265
• /
• 2000

In order to estimate spatial physicochemical properties of the spring waters in the study area, spring waters at 57 sites were investigated for measuring ten items (temperature, pH, Eh, EC, TDS, DO, salinity, alkalinity, discharge rate, and surface elevation), To compare each component with one another, regression analysis was carried out. Kriging was used to estimate the spatial characteristics and continuity of data in the study area. To solve kriging equation, the semivariogram was calculated using geostatistical software GS$^{+}$(version 3.1). As a result of semivariogram analysis, the data of nine components but surface elevation could be assumed as stationary random function, and ordinary kriging method was used for making contour maps.s.

• The Transactions of the Korea Information Processing Society
• /
• v.7 no.5S
• /
• pp.1708-1718
• /
• 2000

In the operating of electronic commerce system, the information about consumer purchasing intention to product through e-mail has caused the problems in the management aspects. These are the using of information again and response to the situations promptly in consumer purchasing intension, etc. Moreover, it has brought out the issues timely to operate the electronic commerce system strategically with reapplication of consumer intention information. In this studies, the agent system AWEC(Agent Windows for EC) was proposed as an alternative paln, which charges of he getting and transmitting information of consumers intension in the electronic commerce system. In this proposed AWEC, the functional structure and working allocation were executed. And also eh performance of the proposed system is analyzed and evaluated through experiment.

• Korean Journal of Soil Science and Fertilizer
• /
• v.27 no.1
• /
• pp.40-47
• /
• 1994

The objective of this research was to examine the effect of ammonium thiosulfate(ATS) on urease activity and on biological and chemical properties of flooded paddy soil especially having high organic matter content by comparing with the effect of sodium thiosulfate(STS). The results obtained are summarized as follows. 1. The hydrolysis of urea was inhibited at 3 and 5 days after treatment of thiosulfate(ATS and STS) +glucose and thiosulfate only, respectively. The inhibitory effect of ATS on urea hydrolysis was slightly lower than that of STS in glusoce-added soils, but when the glucose was not added, the effects of ATS and STS were not different significantly. 2. The soil pH and Eh was lowered by 0.3~0.5 units and 30~120 mV, respectively, when incubated flooded soil with ATS and glucose at $25^{\circ}C$. 3. Soil respiration rate in/flooded soil was increased by 10~70% with the treatment of ATS during the 20 day experimental period. 4. The contents of acetic and butyric acid in thiosulfate treatment soil was below $10{\mu}g/g$, which was lower than that($220.3{\mu}g/g$) of critical growth inhibition of rice.

• KSBB Journal
• /
• v.19 no.1
• /
• pp.38-41
• /
• 2004

Enantioselective hydrolysis for the producing chiral epichlorohydrin from its racemic substrate was investigated using epoxide hydrolase activity of Rhodosporidium toruloides SJ-4. The effects of reaction parameters including pH, temperature, initial substrate concentration on initial hydrolysis rate and enantioselectivity were analyzed and optimized. The addition of detergent, Tween 20, enhanced the hydrolysis rate and enantioselectivity. Chiral (R)-epichlorohydrin with high optical purity (＞99% ee) and yield of 25% (theoretically 50% maximum yield) was obtained from its racemate of 20 mM.

• Proceedings of the KSEEG Conference
• /
• 2004.12a
• /
• pp.9-28
• /
• 2004

Concern about arsenic is increasing throughout the world, including areas of the United States. Elevated levels of arsenic above current drinking-water regulations in ground and surface water can be the result of purely natural phenomena, but often are due to anthropogenic activities, such as mining and agriculture. The current study correlates arsenic speciation in acid mine drainage and mining influenced water with the important water-chemistry properties Eh, pH, and iron(III) concentration. The results show that arsenic speciation is generally in equilibrium with iron chemistry in low pH AMD, which is often not the case in other natural-water matrices. High pH mine waters and groundwater do not 짐ways hold to the redox predictions as well as low pH AMD samples. The oxidation and precipitation of oxyhydroxides depletes iron from some systems, and this also affects arsenite and arsenate concentrations differently through sorption processes.

• Journal of Sericultural and Entomological Science
• /
• v.34 no.1
• /
• pp.57-71
• /
• 1992

These studies were carried out to establish Korean opinion about "The electronic method of raw silk testing and grading" which was taken shape along with the report by Silk Standard Committee(S.S.C.) at the meeting of International Silk Association(I.S.A) Directing Board session held in Zurich Swiss. This establishment was througly examine whether or not the above are the essential factors to be fulfilled in force as a international standard method of raw silk testing and grading.d grading.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.15
• /
• pp.6053-6057
• /
• 2014

Aim: To determine utility of the frozen section (FS) in the operative management of endometrial pre-malignant lesions. Materials and Methods: We retrospectively analyzed patients who underwent abdominal hysterectomy with preoperative diagnosis of complex atypical endometrial hyperplasia (CAEH) and simple endometrial hyperplasia (SEH) between May 2007 and December 2013. Frozen and paraffin section (PS) results were compared. Sensitivity, specificity, the positive predictive value (PPV), the negative predictive value (NPV) and the accuracy in predicting EC on FS were evaluated with 95% confidence intervals (CIs) for each parameter. The correlation between FS and PS was calculated as an ${\kappa}$ coefficient. Results: Among 143 preoperatively diagnosed CAEH cases, 60 (42%) were malignant and 83 (58%) were benign in PS; and among 60 malignant cases diagnosed in PS, 43 (71%) were "malignant" in FS. Sensitivity, specificity, PPV and NPV for FS were 76%, 100%, 100% and 87.5%, respectively. Conclusions: We found that FS is reliable and applicable in the management of endometrial hyperplasias. It is important that the pathologist should be experienced because FS for endometrial pre-malignant lesions has significant inter-observer variability. The other conclusion is that patients with the diagnosis of EH, especially those who are postmenopausal, should undergo surgery where FS investigation is available.

• Economic and Environmental Geology
• /
• v.32 no.5
• /
• pp.469-483
• /
• 1999

Two different types of deep groundwaters occur together in the Jungwon area: $CO_2$-rich water and alkali water. Each water shows distrinct hydrogeochemical and environmental isotopic characteristics. The $CO_2$-rich waters are characterized by lower pH(6.0~6.4), higher Eh (25~85mV) and higher TDS content (up to 3,300 mg/l), whereas the alkali type waters have higher pH (9.1~9.5), lower Eh (-136~-128mV) and lower TDS content (168~254 mg/l). The CO2-rich waters ($Pco_2$=up to 1atm) were probably evolved by the local supply of deep $CO_2$ during the deep circulation, resulting in enhanced dissolution of surrounding rocks to yield high concentrations of $Ca^{2+}, Na^+, Mg^{2+}, K^+\; and \;HCO_3\;^-$ under low pH conditions. On the other hand, the alkali type waters ($Pco_2$=about 10-4.6 atm) were evolved through lesser degrees of simple wate/rock (granite) interaction under the limited suppy of $CO_2$. The alkali waters are relatively enriched in F- (up to 14mg/l), whereas the F- concentration of$CO_2$-rich water is lower (2.2~4.8 mg/l) due to the buffering by precipitation of fluorite. The oxygen-hydrogen isotopes and tritium data indicate that compared to shaltion ($\delta$18O=-9.5~-7.8$\textperthousand$),two different types fo deep groudwaters (<1.0TU)were both derived from pre-thermonuclear (more than 40 years old) meteoric waters with lighter O-H isotopic composition ($\delta$18O=-9.5~-7.8$\textperthousand$) and have evolved through prolonged water/rock interaction. The $CO_2$-rich waters also show some degrees of isotopic re-equilibration with $CO_2$ gas. The $\delta^{34}S$ values of dissolved sulfates (+24.2~+27.6$\textperthousand$) in the $CO_2$-rich waters suggest the reduction of sulfate by organic activity at depths. The carbon isotope data show that dissolved carbon in the $CO_2$-rich waters were possibly derived either from dissolution of calcite or from deep $CO_2$ gas. However, strontium isotope data indicate Ca in the $CO_2$-rich waters were derived mainly from plagioclase in granite, not from hydrothermal calcites.