• 한국산림과학회지
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• 제99권3호
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• pp.404-413
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• 2010

본 연구는 중요도-만족도 분석(Importance-Satisfaction Analysis)을 적용하여 한밭수목원 내 산책로에 대한 이용객의 기대정도와 만족정도를 조사하였다. 분석결과 서원은 평균점으로 볼 때 중요도가 3.85, 만족도가 3.67로 나타났으며 동원은 중요도가 3.99, 만족도가 3.78로 나타났다. 전반적으로 이용하기 전보다 이용 후 만족도가 낮은 것으로 평가되었다. 평가항목들의 대부분이 중요도가 만족도보다 높은 것으로 나타났다. 서원은 산책로의 안전시설, 산책로의 배수시설, 위험지 등에 대한 안내판 항목에서 집중적인 관리가 필요한 것으로 나타났다. 또한 동원은 산책로를 이용하여 휠체어나 유모차 등 이동의 용이성과 산책로의 안전시설 항목에서 집중적인 관리가 필요한 것으로 나타났다. 본 연구 결과가 앞으로 효율적인 관리 및 운영방안을 제시하고 이용객의 질적 만족도를 높일 수 있을 것으로 기대한다.

• 한국환경교육학회지:환경교육
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• 제22권1호
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• pp.12-30
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• 2009

The relationship between marine environmental improvement and environmental perception of the inhabitants was investigated. For this purpose, the seawater and bottom materials were analysed. Apart from this, the questionnaire surveys were also conducted around the Sun-so coastal area. In order to examine the improvement in the marine environment, 12 monitoring sites, which are located around Sun-so coast and can be divided into two parts such as inland (GW1-GW6) and outland (GW7-GW12) sea, were chosen. All the collected samples were analyzed to find out the quality of seawater (temperature, pH, salinity, dissolved oxygen: DO, chemical oxygen demand: COD and suspend solid: SS), nutrients (total nitrogen: TN and phosphate: $PO_4-P$) and bottom materials (COD, volatile solids: VS) as per the standard analytical procedures. In addition, the questionnaire mainly focused on the following three factors: 1) social economy, 2) dependent environmental awareness and 3) independent environmental awareness related with the environmental education. The monitoring studies indicated that the marine environment of the Sun-so coast showed various trends for analyzing parameter. No significant temporal changes in temperature, pH and salinity were observed. However, the other parameters showed decreasing (COD, SS, TN, $PO_4-P$ and VS) and increasing (DO) trends according to the quality of seawater and bottom materials. The questionnaire survey clearly showed that most of the residents in Sun-so recognized the improvement of marine environment as compared with the situation experienced in the past. The dredging project which is closely related with economic and living conditions of the local residents led to alter the environmental perceptions and attitudes. The survey also indicated that the inhabitants perceived the necessity of the environmental education (87% of respondents) and preferred regular schooling (55% of respondents) as effective and practical education methods.

• Nuclear Engineering and Technology
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• 제53권9호
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• pp.3003-3011
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• 2021

A FAC (flow-accelerated corrosion) test was performed for a straight pipe composed of the SA335 Gr P22 and SA106 Gr B (SA106-SA335-SA106) types of steel with welds as a function of the flow rate in the range of 7-12 m/s at 150 ℃ and with DO < 5 ppb at pH levels ranging from 7 to 9.5 up to a cumulative test time of 7200 h using the FAC demonstration test facility. Afterward, the experimental pipe was examined destructively to investigate opposite effects as well as entrance effects. In addition, the FAC rate obtained using a pipe specimen with a 50 mm inner diameter was compared with the rate obtained from a rotating cylindrical electrode. The effects of the complicated fluid flows at the elbow and orifice of the pipeline were also evaluated using another test section designed to examine the independent effects of the orifice and the elbow depending on the distance and the combined effects on orifice and elbow. The tests were performed under the following conditions: 130-150 ℃, DO < 5 ppb, pH 7 and a flow rate of 3 m/s. The FAC rate was determined using the thickness change obtained from commercial room-temperature ultrasonic testing (UT).

• 한국균학회지
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• 제41권3호
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• pp.181-184
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• 2013

충남 금산군과 전남 완도군, 제주도 송악산 등지에서 서식하고 있는 야생화들로부터 Rhodosporidium fluviale 201-C-1과 Kluyveromyces thermotolerans 150-JE-2(1), Rodosporidium paludigenum과 Candida sp. 80-J-3등의 국내 미기록 효모들을 분리, 선발하여 이들의 미생물학적 특성들을 조사하였다. Rhodosporidium fluviale 201-C-1은 내염성의 무포자 효모로 의균사를 형성하였고 urease 활성을 갖고 있었다. Kluyveromyces thermotolerans 150-JE-2(1)는 내당성과 내염성을 가진 무포자효모로서 $30^{\circ}C$, pH 4.0~6.0에서 잘 생육하였다. Candida sp. 80-J-3과 Rhodosporidium paludigenum 86-J-1 균주들은 모두 무성생식을 하는 무포자 효모들이었고 YPD 배지, Vitamin-free 배지와 5% NaCl을 함유한 YPD 배지 등에서 잘 생육하였다. 또한 Candida sp. 80-J-3 균주의 urease 활성은 음성이었으나 Rhodosporidium paludigenum 86-J-1 균주는 urease 활성이 양성이면서 pH 7.0~8.0에서 잘 생육하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.197-197
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• 2011

In this study, in contrast with cases in which Scanning Tunneling Microscopy (STM) tip-induced reactions were instigated by the tunneling electrons, the local electric field, or the mechanical force between a tip and a surface, we found that the tungsten oxide (WO3) covered tungsten (W) tip of a STM acted as a chemical catalyst for the S-H dissociative adsorption of phenylthiol and 1-octanethiol onto a Ge(100) surface. By varying the distance between the tip and the surface, the degree of the tip-catalyzed adsorption could be controlled. We have found that the thiol head-group is the critical functional group for this catalysis and the catalytic material is the WO3 layer of the tip. After removing the WO3 layer by field emission treatment, the catalytic activity of the tip has been lost. 3-mercapto isobutyric acid is a chiral bi-functional molecule which has two functional groups, carboxylic acid group and thiol group, at each end. 3-Mercapto Isobutyric Acid adsorbs at Ge(100) surface only through carboxylic acid group at room temperature and this adsorption was enhanced by the tunneling electrons between a STM tip and the surface. Using this enhancement, it is possible to make thiol group-terminated surface where we desire. On the other hand, surprisingly, the WO3 covered W tip of STM was found to act as a chemical catalyst to catalyze the adsorption of 3-mercapto isobutyric acid through thiol group at Ge(100) surface. Using this catalysis, it is possible to make carboxylic acid group-terminated surface where we want. This functional group-selective adsorption of bi-functional molecule using the catalysis may be used in positive lithographic methods to produce semiconductor substrate which is terminated by desired functional groups.

• ALGAE
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• 제20권2호
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• pp.133-140
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• 2005

Daily variation of phytoplankton community and environmental parameters were investigated at the lower Nakdong River (Mulgum) from January 2002 to December 2003 to investigate the dynamics of a phytoplankton community in detail. The daily results of water quality in this investigation showed pH (8.1 $\pm$ 0.7), DO (10.3 $\pm$ 2.7 $mg{\cdot}l^{-1}$), water temp. (18.8 $\pm$ 7.4°C), BOD (2.4 $\pm$ 1.0 $mg{\cdot}l^{-1}$), COD (5.3 $\pm$ 1.2 $mg{\cdot}l^{-1}$) and chl. a (43.5 $\pm$ 35.1 mg ${\cdot}m^{-3}$). The results of nutrient factors were the following: TN (3.1 $\pm$ 0.8 $mg{\cdot}l^{-1}$), NO3-N (2.5 $\pm$ 0.5 $mg{\cdot}l^{-1}$), TP (90 $\pm$ 48 ${\mu}g\;{\cdot}\;l^{-1}$), PO4-P (43 $\pm$ 30 ${\mu}g\;{\cdot}\;l^{-1}$). Dominant phytoplankton species during the study period were diatom (Stephanodiscus hantzschii, Aulacoseira granulata var. angustissima and A. italica) and cyanobacteria (Microcystis aeruginosa, Aphanizomenon flos-aquae). The small centric diatom, Stephanodiscus hantzschii, was repeatedly dominant from late fall to the following spring (mean and maximum cell density, 2.3 × 103 $\pm$ 3.8 × 103, 4.5 × 105 cells $ml^{-1}$, respectively). Pinnate diatom, Aulacoseira granulata var. angustissima and A. italica, were frequently observed all season except January to March. Cyanobacteria, Microcystis aeruginosa and Aphanizomenon flos-aquae, proliferated in summer of 2002 except in 2003 due to heavy precipitation. The dominant zooplankton species (March-early May) was rotifer (Brachionus, Keratella, Polyarthra) and cladocerans (Diaphanosoma). The daily observed dynamics of the phytoplankton community in the lower Nakdong River in this study may play an important role in increasing the detailed resolution of limnological information and serving as ecological data for future studies.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2004년도 학술.기술논문발표회
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• pp.51-55
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• 2004

Generally, aggregate may limit the strength of concrete, and aggregate with undesirable properties including strength, shape and grading etc. cannot produce good concrete. Also, the properties of aggregate greatly affect the durability and structural performance of concrete. Recently, it has increased the using of crushed aggregate for concrete due to the exhaustion of good natural aggregate. In case of Korea, the using ratio of crushed stone occupies about 97％ of whole coarse aggregate, and ratio of crushed sand occupies about 18.3％ of whole fine aggregate. This is an experimental study to compare and analyze the properties of crushed sand for concrete in capital region and concrete according to the replacement ratio of crushed sand to do suitable mix design and improve the concrete quality. According to results, it was found that nearly all the properties of crushed sand satisfied with the value recommended by KS.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.339-339
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• 2013

We study on the optical and electrical properties of indium-free ZTO(ZnSnO)/Ag/ZTO (ZAZ) multilayer electrodes for the low-cost transparent electrode. In the first step, each single layer was deposited using rf magnetron in-line sputter with various working pressure based on $O_2$/$Ar+O_2$ ratio (0~3%) and power at room temperature. Secondly, we studied the optical and electrical properties by analyzing the refractive index, extinction coefficient, transmittance and resistivity of each layer. Finally, we optimized the thickness of each layer using macleod simulation program based on the analyzed optical properties and fabricated the multilayer electrode. As a result, We achieved a low sheet resistance of $11{\Omega}$/sq and anaverage transmittance of 80% in the visible region of light (380~780 nm). This indicates that indium-free ZAZ multilayer electrode is a promising low-cost and low-temperature processing electrode scheme.

• 한국분말재료학회지
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• 제16권4호
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• pp.249-253
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• 2009

3-D shape soft magnetic composite parts can be formed by general compaction method of powder metallurgy. In this study, the results on the high density nanostructured Fe-Si/Fe composite prepared by a warm compaction method were presented. Ball-milled Fe-25 wt.%Si powder, pure Fe powder and Si-polymer were mixed and then the powder mixture was compacted at various temperatures and pressures. Pore free density of samples up to 95% theoretical value has been obtained. The warm compacted sample prepared at 650 MPa and 240$^{\circ}C$ had highest compaction properties in comparison with other compacts prepared at 300, 400 MPa and room temperature and 120$^{\circ}C$. The magnetic properties such as core loss, magnetization saturation and coercivity were measured by B-H curve analyzer and vibration sample magnetometer.

• 한국분말재료학회지
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• 제18권4호
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• pp.365-371
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• 2011

In this study, gradient porous Al-Cu sintered body was fabricated by powder metallurgy processing. Al-Cu powder mixtures were prepared by low energy ball milling with various milling time. After ball milling for 3h, the shape of powder mixtures changed to spherical type with size of 100~500 ${\mu}m$. Subsequently, Al-Cu powder mixtures were classified (under 150, 150~300 and over 300 ${\mu}m$) and compacted (20, 50 and 100 MPa). Then, they were sintered at $600^{\circ}C$ for various holding time (10, 30, 60 and 120 min) in $N_2$ atmosphere. The sintered bodies had 32~45% of porosity. As a result, the optimum holding time was determined to be 60 min at $600^{\circ}C$ and sintered bodies with various porosity were obtained by controlling the compacting pressure.