• Journal of Korea Soil Environment Society
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• v.2 no.1
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• pp.51-61
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• 1997

The objective of this study is to evaluate the feasibility of Pumping-and-Treatment system (PTS) for remediation of the saturated zones contaminated with NAPLs. A simulation is carried out for the removal of DNAPLs (denser-than-water non-aqueous phase liquids) and LNAPLS (lighter-than-water non-aqueous phase liquids) distributing at and below the water table. In the study, LNAPL and DNAPL are assumed to be n-hexane and 1,1-dichloroacetone, respectively. The model system studied consists of four heterogeneous soil layers with different permeabilities. Groundwater flows through the bottom layer and a pumping well is located under the initial water table. The time-driven deformation of the water table and removal efficiency of contaminants are estimated after vacuum application to the inlet of the well. In the calculation, FVM (Finite Volumetric Method) with SIMPLEC algorithm is applied. Results show that removal efficiencies of both DNAPL and LNAPL are negligible for the first 5 days after the PTS operation. However, when the cone-shape water table is formed around the inlet of the pumping well, the rapid removal rate is obtained since NAPLs migrate rapidly through the curvature of the water table. The removal efficiency of DNAPL is estimated to be higher than that of LNAPL due to the gravity. The results also show that the fluctuation or cone-shaped depression of the water table enhances the removal efficiency of NAPLs in saturated zones. The simulation results could provide a basis of the PTS design for the removal of NAPLs in saturated zones.

• Solar Energy
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• v.10 no.1
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• pp.5-13
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• 1990

In the present investigation, experiments and numerical analysis during melting process of a phase change material were performed to research heat transfer phenomena generated by means of conduction and natural convection in the vertical tube at inward melting. The phase change material used in the experiments is 99 percent pure n-Docosane paraffin($C_{22}H_{46}$). In the results, it is found that the velocity of phase change interface at the top of tube is faster than at the bottom of tube because of the effect of natural convection, and the distribution of velocity at the liquid region is little affected by the initial temperature of phase change material. The velocity of phase change interface is slower as the initial temperature of phase change material is lower, and the effect of natural convection is larger as the aspect ratio of tube is larger. In tendency of heat transfer phenomena, the experimental results were well corresponded with numerical results. But there were a little disagrements between the results of experiment and numerical analysis because of the assumption of the constant volumetric expansion coefficient in numerical analysis.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.04a
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• pp.135-136
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• 2003

알코올 분무, 셀로판지 부착 등의 표면처리가 포장김치의 표면갈변과, pH, 산도, 균수 및 관능적 품질에 미치는 영향을 조사하였다. 실험에 사용된 포장김치는 200 g 들이 플라스틱 용기에 김치를 담은 후 무처리, 70% 알코올로 표면을 1회 분무한 것, 김치표면에 폴리에틸렌필름(두께 0.04 mm)을 부착하여 저장실 (10$\pm$1$^{\circ}C$)에서 21일간 저장하면서 3일 간격으로 조사하였다. 그 결과, 무처리와 알코올을 분무한 경우는 저장 15일째에 pH가 4.0수준에 도달하였으나 김치표면에 polyethylene film을 부착한 경우는 21일째까지도 pH가 4.0 이상을 유지하였다. 산도의 경우도 pH와 동일한 경향을 나타내어 polyethylene film으로 표면처리함으로서 김치의 숙성이 지연되었다. 무처리와 알코올을 처리한 것은 12일째부터 김치표면이 갈변하기 시작하였으며 18일째는 그 갈변정도가 심하였다. 그러나 polyethylene film을 표면에 부착한 경우는 저장 21일째까지도 갈변정토가 미약하였다. 저장기간에 따른 총균수의 변화는 무처리와 알코올을 처리한 경우가 polyethylene film을 부착한 경우에 비하여 증가폭이 컸으나 젖산균수는 반대로 polyethylene film을 부착한 경우가 무처리 또는 알코올을 분무한 경우에 비하여 높아 김치의 품질이 양호하였다. 무처리와 알코올을 분무한 김치의 표면에는 저장 15일 이후에 산막표모 및 곰팡이의 균사체가 번식하는 김치도 발견되었다. 처리별 이미 및 이취의 발생정도를 조사한 결과 무처리와 알코올을 처리한 경우는 저장 15일경에 특히 용기 표면에 위치하는 김치에서 이미와 이취가 있었으나 polyethylene film을 부착한 경우는 이미와 이취가 전혀 나타나지 않았다.채반에 넣고 밀도를 측정한 결과 1.002g/㎤을 나타냈다. 즉 물의 이론밀도인 1g/㎤에 근접한 값을 보여 정확한 밀도 계측이 가능한 것으로 판단되었다. 또한 밀도 계측시스템의 측정 반복간 정밀도를 파악하기 위해 수박 6개를 임으로 선정하여 3반복 측정 시험한 결과, 측정표준편차가 0.001~0.004g/㎤로 해상도보다는 다소 높았으나 대체로 양호한 결과를 나타냈다. 수박 35개를 이용하여 개발 계측시스템과 사람이 직접 부력법으로 밀도를 측정 비교한 결과, 계측시스템에 의해 측정된 수박 밀도가 사람이 측정했을 때 보다 낮게 측정되었다. 수박의 외관인자(무게, 길이, 직경, 체적), 밀도와 당도의 상관관계 구명시험을 위해 원예연구소 시험포장에서 재배된 삼복꿀수박 총 74개를 공시재료로 하였고, 시험은 출수일별로 10~14개씩 수확하여 외관인자, 밀도, 당도를 각각 측정하고, 이들 인자들간의 상관관계를 구명하였다. 외관인자들간에는 높은 상관관계를 보였으나, 외관인자들과 밀도, 외관인자들과 당도, 밀도와 당도와는 매우 낮은 상관관계를 나타냈다. 점성에 영향을 미치는 가장 주요한 조건이라고 생각된다.환원당인 sucrose 함량은 계속 증가하였고 fructose, glucose, sorbitol의 함량(추황의 sorbitol을 제외)은 생장이 촉진됨에 따라 증가하다가 다시 점차적으로 감소하였다. 이러한 결과는 총당과 환원당의 측정결과와 일치한 것으로 나타났다. 결론적으로 배의 성장에 따라 산 함량은 감소하였고 당 함량은 증가하였다.luco-pyranoside, quercetin 7-O- -glucopyranoside, acacetin 7-O-$\beta$-D-glucuronide and apigenin-6-C-$\beta$-D-glucopyranosyl-8-C-$\b

• Journal of the Korean Magnetics Society
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• v.14 no.1
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• pp.33-37
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• 2004

Cu$_{0.1}$Fe$_{0.9}$Cr$_2$S$_4$ has been studied with Mossbauer spectroscopy, x-ray diffraction, vibrating sample magnetometer (VSM), and magnetoresistance (MR) measurement. The crystal structure was determined to be a cubic spinel with lattice parameter a$_{0}$=9.9880 $\AA$. The MR measurements show a semiconductor behavior below 110 K and metal behaved above 100 K. The temperature dependence of magnetization of Cu$_{0.1}$Fe$_{0.9}$Cr$_2$S$_4$ was reported. In addition to a large irreversibility between the zero-field-cooling (ZFC) and the field-cooling (FC) magnetization at applied field H=100 Oe, a cusp-like anomaly was observed in both the FC and ZFC curves. It shifted toward the lower temperature region with increasing magnetic field, and then showed convex type maximum at 110 K, under the applied field of 5 kOe. The Mossbauer spectra were measured from 15 K to room temperature. The asymmetric line broadening was observed for the sample Cu$_{0.1}$Fe$_{0.9}$Cr$_2$S$_4$, and it was considered to be dynamic Jahn-Teller relaxation. The charge state of Fe ions was ferrous in character. The unusual reduction of magnetic hyperfine field below 110 K was interpreted in terms of cancellation effect between the mutually opposite orbital current field (H$_{L}$) and Fermi contact field (H$_{C}$).

• Journal of the Korean Magnetics Society
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• v.17 no.2
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• pp.86-89
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• 2007

[ $FeCr_2Se_4$ ] prepared under the high pressure (3 GPa) has been studied with x-ray, neutron diffraction techniques, superconducting quantum interference device (SQUID) magnetometer, resistance, and Mossbauer spectroscopy. The temperature dependence of resistance is explained by Mott-VRH and small polaron model for the regions I (T<20 K) and II (T>42 K), respectively. Neutron diffraction results show an antiferromagnetic spin-lattice coupling near the Neel temperature. So finally the distance of atom is enlarged in region (110$FeCr_2Se_4$ shows convex type of temperature dependence.

• Journal of the Korean Geotechnical Society
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• v.18 no.2
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• pp.75-86
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• 2002

This paper presents sedimentation and consolidation characteristics of dredged soils mixed with sand materials through the self-weight consolidation tests adopting stepwise filling method. After completely throwing away dredged soils daily by flour kinds of S-C, which is the quantity of sand contained, results fi:om laboratory tests are compared with those from a new method using hyperbolic, which considers stage settling and consolidating characteristics, and those from the existing analyzing method. Liquid limit up to 65% had a large effect on consistency properties. Assuming that the settlement occurred only by clay content of dredged soils, it is shown that the clay void ratio is less than 2 and 4 respectively in case S-C is 0% and 50%. In the applied hyperbolic method, reinitialized curve has a linear behavior of a coefficient of correlation of almost 1, and the coefficient of slope and intercept except fur the specimen with the height of 10cm and 20cm had a tendency to fellow exponent function and a shape of zone settling and dispersing settling. The results computed by the applied hyperbolic method rather than the existing analyzing method coincide with those of laboratory tests. It is shown that the former is more suitable than the latter for the area considering the influence, of sand materials.

• Journal of Environmental Science International
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• v.5 no.6
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• pp.813-826
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• 1996

The toxic effects of aluminium (Al) on growth, chlorophyll content, $\delta-aminolevulinic$ acid dehydratase (ALAD) activity and anatomy of root and shoot were investigated in 7-day-old azuki bean (Vigna angularis) seedlings. Significant depressions in root elongation was observed in the low concentrations of Al (50, 100 $\muM)$ and increasing Al concentrations caused a sharp decline of root and shoot growth. The degree of inhibition was dependent upon Al supply. Exposure to 50 $\muM$ Al or more inhibited root elongation within 1 day. In the 50 $\muM$ Al treatments, a recovery of root growth was seen after 7 days exposure. In contrast, lateral root initials was little affected by Al exposure. Al toxicity symptoms and growth responses were more well developed in the roots than in the shoots. Analysis of Al localization in root cells by hematoxylin stAlning showed that Al entered root apices and accumulated in the epidermal and cortical cells immeadiately below the epidermis. There was a good positive correlation between the level of chlorophyll and ALAD activity. Increasing Al concentrations caused a decrease in total chlorophyll contents, accompanied by proportional changes in ALAD activity, suggesting a cootr-dinated reduction of a photosynthetic machinery. Al exerted specific influence on the morphology of root ann shoot. At higher concentrations of Al the roots induced drastic anatomical changes. The epidermal cells were disorganized or destructed while the cortical cells exhibited distortion of cell shape and/or disintegration. The diameter of root and transectional area of cortical cells decreased considerably with Al treatment. In the shoot Al also enhanced reduction of diameter of shoot and cell size. Gross anatomy of leaves treated with Al did not differ significantly from the controls, except for fewer and smaller chloroplast. Our results indicate that toxic effect of Al appear to be manifested primarily in roots and secondarily on shoots, and changes in root morphology are related to changes in the root growth patterns. Results are further discussed in re181ion to the findings in other plant species, and it is concluded that Al causes morphological, structural and, presumably, functional damage to the roots of the species investigated.

• Journal of Life Science
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• v.30 no.6
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• pp.563-569
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• 2020

Oncoplastic surgery (OPS) combines oncologically safe tumor resection with aesthetically satisfying reconstruction of defects using established plastic surgery techniques. OPS is characterized by initial excision as extensive as is beneficial for oncological safety, and, once sufficient resection is complete, displacement or replacement techniques are selected based on remnant volume. The size of the lesion and the individual patient are important factors when considering the appropriate approach, and when pre-operative imaging, including MRI, is used to determine the technique, the complete removal of cancer cells by permanent pathology is essential. A frozen section is used during the operation to reduce the reoperation rate, but it is difficult to cover the entire margin surface theoretically and even harder in practice. A recent report about adequate margins has empowered OPS in its oncological safety. Considering the patients to whom each modality could be applied, basic breast volume is an important factor, and this is influenced by ethnic differences. In Europe or the US, for example, the average breast size is 36D (600 ㎤) and reduction mammoplasty is predominantly used. However, the average size of patients in our institution is 33A (300 ㎤), and so quite different approaches are selected in most cases. New techniques involving radiofrequency and fluorescence have been proposed as safe and easily accessible ways of reducing complications.

• Korean Journal of Food Science and Technology
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• v.38 no.5
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• pp.712-716
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• 2006

Saccharomyces cerevisiae and Zygosaccharomyces rouxii were electrofused and fermented in germaniumfortified nutrients to produce high-yield, organic germanium. The conditions for the preparation of protoplasts from both strains and for electrofusion were studied. The protoplasts of both cells formed long pearl chains and the cell membranes were lysed and fused through cellulase and high frequency voltage $(450{\sim}750V/128{\sim}512\;{\mu}sec)$. The fusants with the fastest growth were selected, and then characterized for their carbohydrate usage and tolerance to glucose and salts. The glucose tolerance of the fusants was better than that of S. cerevisiae and similar to that of Z. rouxii. The fusants appeared to have resistance to 12% NaCl. The cell size of the fusants was greater than that of the parental strains. The fusant cells contained more gemlanium than the parental cells did. The electrofusion of S. cerevisiae and Z. rouxii increased the cell capacity and accumulation of germanium in the yeasts. This method was proved to be effective to produce a high quantity of organic germanium.

• Journal of Korean Tunnelling and Underground Space Association
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• v.8 no.3
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• pp.259-271
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• 2006

This paper aims to predict the corrosion of a fully cement-grouted rockbolt induced by chloride diffusion in a cement mortar grout. From the viewpoint of the long-term durability, a rockbolt may be deteriorated by chemical components, such as sulphate and chloride, in groundwater. Especially, the steel rod of a rockbolt is corroded mainly by chloride. The rockbolt corrosion results in the volume expansion of a rod and then the cracking of a cement grout. In this study, the chloride diffusion coefficient of a cement mortar grout was used to evaluate the possibility of rockbolt corrosion by chloride, and to predict the long-term durability of a rockbolt. The electric acceleration test method was adopted to measure the chloride diffusion coefficient. In addition, a simple pullout testing system was newly proposed to measure the pullout capacity of a rockbolt more easily in a laboratory condition. From the experiments, it was showed that the chloride could diffuse in the cement grout more easily than in ordinary concrete materials. As a result, it was considered that a rockbolt might be easily corroded in a short term by the diffusion of chemical components with high concentration, although it was fully grouted.