• 한국표면공학회지
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• 제9권3호
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• pp.1-4
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• 1976

In order to get high wear-resistant gold alloy plating on electronic parts, on attempt has been made, in which Cu, Ni, and Zn EDTA salts were added in gold palting solution. The results obtained on the wear resistance are as follows: 1. The addition of 0.5g/ι or over Cu in plating solution, showed 1.5 times more wear resistance than in case of no addition. 2. The addition of 1.5g/ι or over Ni, showed 3.5 times more wear-resistance . 3. The addition of 1.5g/ι and 4.0g/ι Zn , showed 3.5 times and 6.8 times more wear resistance , respectively. 4. The addition of 1.5g/ι Ni and 1.0g/ι Zn simultaneously , showed about 10 times more wear resistance than in case of no addition.

• 분석과학
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• 제25권6호
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• pp.435-440
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• 2012

지표수 중에 과염소산이온을 LC-ESI-MS/MS을 사용하여 분석하였다. 시료는 단지 PTFE 필터를 사용하여 거른 후 LC-ESI-MS/MS 시스템에 직접 주입하여 분석하였다. 이 방법은 3% 이내의 정밀도를 보였고 정량한계는 0.17 ${\mu}g/L$이었다. 시료는 금강물 35 개 유역에서 2, 4, 6월에 각각 시료를 채취하였다. 그 결과 일반 하천수에서는 과염소산이온이 0.23-3.73 ${\mu}g/L$ (평균 0.20 ${\mu}g/L$) 농도범위로 15% 빈도로 검출되었고 공단 근처의 지표수에서는 0.36-25.10 ${\mu}g/L$ (평균 1.69 ${\mu}g/L$)로 36%의 빈도로 검출되었다.

• 한국조리학회지
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• 제17권5호
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• pp.206-217
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• 2011

본 연구는 설탕 간장을 주로 사용하는 데리야끼소스의 간장, 설탕, 가열시간의 최적화를 구하고자 하였다. 연구 결과를 요약하면 다음과 같다. 간장, 설탕, 가열시간을 독립변수로 하여 관능검사를 실사하였다. 관능검사결과 외관, 맛, 전반적인 기호도에서 유의적으로 차이를 보였고, 소스의 외관에는 가열시간이 가장 큰 영향을 미쳤고, 맛은 설탕, 가열시간, 간장순으로 영향을 미쳤으며, 전반적인 기호도는 간장, 가열시간, 설탕순으로 영향을 미쳤다. 종합하면 간장은 1,182.76 g -1,210.11 g, 설탕은 843.97 g - 851.17 g, 가열시간은 174.49 분 - 181.46 분의 범위에서 데리야끼소스를 제조함이 좋은 것으로 나타났고, 최적은 간장 1,196.44 g, 설탕은 847.57 g, 가열시간은 177.98 분으로 하여 데리야끼소스를 제조함이 적당한 것으로 나타났다.

• 한국재료학회지
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• 제29권10호
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• pp.623-630
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• 2019

Because of their excellent stability and highly specific surface area, carbon based materials have received attention as electrode materials of electrical double-layer capacitors(EDLCs). Biomass based carbon materials have been studied for electrode materials of EDLCs; these materials have low capacitance and high-rate performance. We fabricated tofu based porous activated carbon by polymer dissolution reaction and KOH activation. The activated porous carbon(APC-15), which has an optimum condition of 15 wt%, has a high specific surface area($1,296.1m^2\;g^{-1}$), an increased average pore diameter(2.3194 nm), and a high mesopore distribution(32.4 %), as well as increased surface functional groups. In addition, APC has a high specific capacitance($195F\;g^{-1}$) at low current density of $0.1A\;g^{-1}$ and excellent specific capacitance($164F\;g^{-1}$) at high current density of $2.0A\;g^{-1}$. Due to the increased specific surface area, volume ratio of mesopores, and surface functional groups, the specific capacitance and high-rate performance increased. Consequently, the tofu based activated porous carbon can be proposed as an electrode material for high-performance EDLCs.

• 한국응용과학기술학회지
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• 제27권3호
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• pp.310-317
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• 2010

The electrochemical properties of electric double layer capacitor(EDLC) was studied by controlling pore size distribution and specific surface area of the activated carbon fiber(ACF). The mesoporous ACF, which was prepared by the iron exchange method, showed the tendency of increasing average pore size and decreasing total surface area. The mesoporous ACF (surface area = 2225 $m^2$/g, pore size=1.93 nm) showed increased mesopore(pore size=1~3nm) volume from 0.055 cc/g to 0.408 cc/g compared to its raw ACF. The charging capacity of the EDLC which uses the prepared mesoporous ACF also increased from 0.39 F/$cm^2$ to 0.55 F/$cm^2$. From these results, it can be known that the electrochemical properties of EDLC are mainly dependent on the specific surface area, but above the surface area 2200 $m^2$/g, it is the mesopore volume that affects the performance of the capacitor considerably. Because the increased mesopore volume results in a decreased ion mobility resistance, the charge capacitance is enhanced.

• 대한수학회보
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• 제33권1호
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• pp.97-106
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• 1996

The study of surface in a Euclidean space whose Gauss map G satisfies the condition : \DeltaG = AG(*)$ for some matrix A was studied by C. Baikoussis, D. E. Blair, B. Y. Chen, F. Dillen, L. Verstraelen ([1]1, [2], [7]) and so on.

• 한국환경과학회지
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• 제23권8호
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• pp.1419-1428
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• 2014

Electron beam-induced grafting polymerization was employed to prepare Acrylic acid-grafted bacterial cellulose (BC-g-AAc). BC-g-AAc as an adsorbent was applied to remove heavy metals (e.g., As, Pb, and Cd). This study examined followings; morphological change of surface, adsorptive behavior of BC-g-AAc, and interpretation of adsorptive kinetics. Specific surface areas of BC and BC-g-AAc were $0.9527m^2g^{-1}$ for BC and $0.2272m^2g^{-1}$ for BC-g-AAc, respectively as measured by BET nitrogen adsorption, revealing the morphological change of the surface of BC-g-AAc. Batch adsorption test was performed to investigate adsorptive behavior of BC-g-AAc in aqueous solution. The amounts of Pb and Cd adsorbed on BC-g-AAc were $69mg\;g^{-1}$ and $56mg\;g^{-1}$, respectively. However, As was not adsorbed on BC-g-AAc due to its neutral nature. Both the Benaissa model and the Kurniawan model were applied in the study to interpret adsorptive kinetics. From the value of correction coefficient ($R^2$), adsorptive kinetics of Pb and Cd were subjected to Kurniawan model referred to pseudo-second-order. Taken together, the results of this study show that BC-g-AAc has potential as a heavy metal (eg., Pb, Cd)-adsorbent made of an environmentally friendly material.

• 대한수학회보
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• 제34권1호
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• pp.9-17
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• 1997

Define $\bar{g}{\upsilon, \omega) = -\upsilon_1\omega_1 + \cdots + \upsilon_n\omega_n$ for $\upsilon, \omega in R^n$. $R^n$ together with this metric is called the Lorentzian n-space, denoted by $L^n$, and $R^n$ together with the Euclidean metric is called the Euclidean n-space, denoted by $E^n$. A Lorentzian surface in $L^n$ means an orientable connected 2-dimensional Lorentzian submanifold of $L^n$ equipped with the induced Lorentzian metrix g from $\bar{g}$.

• 한국환경과학회지
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• 제10권4호
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• pp.305-310
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• 2001

pH($H_2O$), pH(KCI), CEC(cation exchange capacity), O.M.(organic matter) and exchangeable cations(K, Na, Ca, Mg) of paddy soil, upland soil and forest soil in Kumi city were investigated for the purpose of knowing soil acidification and the correlation between soil acidification and leaching of inorganic salts. The mean pH($H_2O$) values of paddy soil were 5.23(surface soil) and 5.69(subsoil) and 4.74(subsoil). The were 6.37(surface soil) and 6.11(subsoil), and those of forest soil were 4.67(surface soil) and 4.74(subsoil). The mean pH(KCl) values of paddy soil were 4.59(surface soil) and 4.98(subsoil) were 5.48(surface soil) and 5.04(subsoil), and those of forest soil were 3.82(surface soil) and 3.89(subsoil). The acidification of forest soil was more rapid than that of paddy soil and upland soil/ The total mean amounts of exchangeable cations(K, Na, Ca, Mg) in paddy soils were 6.14me/100g(surface soil) and 5.64me/100g(subsoil), and those in upland soils were 6.86me/100g(surface soil) and 6.65me/100g(subsoil), and those in forest soils were 4.06me/100g(surface soil) and 3.34me/100g(subsoil). The contents of inorganic salts in forest soil were much less than those of paddy soil and upland soil. The correlation coefficients(r) between pH($H_2O$) values and the total amounts of exchangeable cations in soils were $0.6635^{**}$(surface soil) and $0.6946^{**}$(subsoil), and those between pH(KCl) values and exchangeable cations in soils were 0.6629(surface soil) and $0.5675^{**}$(subsoil). The correlation between soil acidification and leaching of inorganic salts in soil was positively significant at 1% level.

• 대한수학회지
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• 제45권4호
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• pp.965-976
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• 2008

In this article, we constructively prove that on a surface S with genus g$\geq$2, there exit maximal geodesic laminations with 7g-7,...,9g-9 leaves. Thus, S can have ideal cell-decompositions (i.e., S can be (ideally) triangulated by maximal geodesic laminations) with 7g-7,...,9g-9 (ideal) 1-cells. Once there is a triangulation for a compact surface, the Euler characteristic for the surface can be calculated as the alternating sum F-E+V, where F, E, and V denote the number of faces, edges, and vertices, respectively. We also prove that the same formula holds for the ideal cell decompositions.