• Journal of Soil and Groundwater Environment
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• v.26 no.5
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• pp.29-38
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• 2021

This study investigated the mineralogical properties of bentonite and illite and evaluated the Cs sorption at various concentrations (C_w≈1-10⁵ ㎍/L). Bentonite samples, collected from South Korea and USA, majorly consisted of Ca- and Na-montmorillonite, showed large cation exchange capacity (CEC, 91.4 and 47.3 meq/100 g) and specific surface area (SSA, 46.1 and 39.7 m²/g). In contrast, illite sample (USA) had relatively low values for 14.4 meq/100g of CEC and 29.3 m²/g of SSA, respectively. Bentonite and illite had different non-linear sorption for Cs along with C_w. At low C_w<10 ㎍/L, illite showed higher sorption capacity than bentonite despite low CEC because of the existence of specific sorption sites at the weathered mineral edge. However, as C_w increased, bentonite represented high sorption capacity because the cation exchange between Cs and interlayer cations was effective at high C_w conditions. These results implicated that the Cs concentration is important to evaluate the sorption performance of bentonite and illite. Finally, the Cuadros' kinetic model for illitization using various K concentrations (2×10^-5 and 1.7×10^-3 mol/L) and temperature (100-200℃) showed that up to 50% of the montmorillonite in bentonite could be converted to illite, suggesting that the illitization should be considered to evaluate the sorption performance of the bentonite in deep geological disposal repository.

• Proceedings of the KSEEG Conference
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• 2001.05a
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• pp.11-113
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• 2001

No Abstract.See Full-text

• Explosives and Blasting
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• v.15 no.3
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• pp.48-58
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• 1997

• The monthly packaging world
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• s.96
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• pp.142-150
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• 2001

• Korean Journal of Optics and Photonics
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• v.20 no.3
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• pp.148-155
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• 2009

In this paper, we analysed what effect the design variables, such as refractive index, central thickness and radius of curvature, had on the first order properties and image quality of optical systems when temperature changed. The optical parameters were varied at each temperature, then the coupling and ruler methods were used to design an athermalized lens for a phone camera. This concept was first used to design the lens for a 1/3.2" 5M phone camera. The designed lens satisfies all the specifications for a phone camera, and the variations of the back focal length(${\Delta}BFL$) are reduced to $10{\mu}m$ for a temperature range of $-10^{\circ}C$ to $+60^{\circ}C$. Also, the TTL of 5.5 mm results in a compact system. All design concepts and results discussed in this paper are expected to be useful in development for the phone and CCTV camera.

• Journal of Korean Society on Water Environment
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• v.26 no.1
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• pp.140-147
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• 2010

In existing design method for aeration tank water temperature was considered as governing variable for applying safety factor. This study tried a few new approach of aeration tank design using SOUR at various temperature conditions. Specific substrate utilization rate (U) and specific oxygen uptake rate (SOUR) both were analyzed at various temperature and SRT. The laboratory scale reactor was operated on various temperature ($10^{\circ}C$, $20^{\circ}C$, $25^{\circ}C$) and SRT (5day, 10day, 20day, 30day). In this study, SOUR tended to increase with the temperature increased. On the other hand, SOUR tended to decrease when SRT increased from 5 days to 30 days. Empirical equations were obtained SOUR=a/SRT+b and $SOUR=(a/m){\cdot}U+(b-a(n/m))$ from the relationship between SRT, U and SOUR. Empirical equations shows the possibility as a new design method for the aeration basin.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.883-887
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• 2009

In this study, a new soil retaining system was proposed by soil cement mixing method. The new soil retaining system is based on deep cement mixing method by large diameter reinforcing blocks (piles). Large diameter reinforcing blocks (usually $\varnothing$300-500 mm) have the advantage to make reinforcements over a relatively short depth and thus reduce the amount of reinforcement necessary. A field case has been reviewed for actual application of the soil retaining system at a downtown site. Research was conducted to evaluate the behavior of the installed soil retaining wall, with reinforcing blocks (400 mm in diameter and 4 m in length) placed into a 10 m excavation wall at a $20^{\circ}$ angle. As a result, the potential for applying this method to the downtown excavation site was confirmed.

• Nuclear Engineering and Technology
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• v.49 no.4
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• pp.810-816
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• 2017

A graphite calorimetry system was built and tested under irradiation. The noise level of the temperature measurement system was approximately 0.08 mK (peak to peak). The temperature of the core part rose by approximately 8.6 mK at 800 MU (monitor unit) for 6-MV X-ray beams, and it increased as X-ray energy increased. The temperature rise showed less spread when it was normalized to the accumulated charge, as measured by an external monitoring chamber. The radiation energy absorbed by the core part was determined to have values of $0.798J/{\mu}C$, $0.389J/{\mu}C$, and $0.352J/{\mu}C$ at 6 MV, 10 MV, and 18 MV, respectively. These values were so consistent among repeated runs that their coefficient of variance was less than 0.15%.

• Korean Journal of Materials Research
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• v.1 no.2
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• pp.71-76
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• 1991

The superconducting powders in $YBa_2Cu_3O_{7-x}$ and Bi-Pb-Sr-Ca-Cu-O system were easily prepared from water in oil type emulsion by loading each cation into the aqueous phase. In $YBa_2Cu_3O_{7-x}$ system, the superconducting orthorhombic phase was formed by calcining at $750^{\circ}C$ for 10h in $O_2$. The size of the superconducting phase powders was submicron. The density of the sintered specimen using this powders was about 95% of the theoretical density and the resistance sharply decreases at about 90K, In Bi-Pb-Sr-Ca-Cu-O system the low Tc phase($(Bi, Pb)_2Sr_2Ca_1Cu_2O_y$) was formed by calcining at $800^{\circ}C$ for 10h in a low oxygen partial pressure of 1/20 atm The shape of clacined powder is thin plate of which size is about $2\mu\textrm{m}$ and thickness is smaller than $\mu\textrm{m}$. It was observed that the high Tc phase ($(Bi, Pb)_2Sr_2Ca_2Cu_3O_y$) was formed by sintering at $850^{\circ}C$ for 30h in oxygen pressure of 1/20 atm without intermediary grinding. The above sintered sample exhibited superconductivity with a Tc(zero)=105K.

• Fisheries and Aquatic Sciences
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• v.19 no.5
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• pp.23.1-23.7
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• 2016

The effects of daily feeding frequency (Exp I), water temperature (Exp II), and stocking density (Exp III) on the growth of river puffer, Takifugu obscurus, juvenile fish of 10 and 40 g in body weight were examined to develop effective techniques to produce river puffer in a non-exchange water system. In Exp I, fish were fed commercial floating feed with 45 % protein one to five times per day to apparent satiation each by hand daily for 8 weeks at $25^{\circ}C$. In both the 10- and 40-g size groups, the final body weight, daily feed consumption, and weight gain of fish fed one meal per day were significantly lower than those of fish fed five meals per day (P < 0.05). However, there were no significant differences in the final body weight, daily feed consumption, and weight gain among fish fed two, three, and five meals per day. Feed efficiency showed decreasing tendency with increasing size of fish. In Exp II, fish of 10 and 40 g in initial body weight were reared with the commercial feed at $15-30^{\circ}C$ for 8 weeks. The weight gain of fish increased with raising water temperature up to $25^{\circ}C$ and decreased drastically at $30^{\circ}C$ for both sizes. The Q10 of specific growth rate was decreased with raising water temperature from 5.04 (temperature interval, $15-20^{\circ}C$) to 0.66 ($25-30^{\circ}C$) for the 10-g fish and from 4.98 to 0.31 for the 40-g fish. In Exp III, the effect of stocking density on growth was examined with fish of 10 and 40 g in initial body weight. The final body weight for initial stocking densities of 4, 8, and $12kg/m^3$ was significantly higher than that of $20kg/m^3$ for the 10-g fish, and the final stocking density reached 10.1, 19.2, 28.7, and $39.9kg/m^3$, respectively. For the 40-g fish, the final body weight for initial stocking densities of 3 and $6kg/m^3$ was significantly higher than that of 9 and $15kg/m^3$ and the final stocking density reached 7.38, 13.5, 17.1, and $27.5kg/m^3$, respectively (P < 0.05). In both groups, weight gain tended to decrease with increasing stocking density; however, survival showed no significant difference.