• Economic and Environmental Geology
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• v.36 no.3
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• pp.159-170
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• 2003

Heavy metals are extracted from Chonju stream sediment, roadside soils and sediments along Honam expressway, soils and tailings from mining area using three different methods (partial extraction in Standard Method, partial extraction method with maintaining 0.1 N of extraction solution and Sequential Extraction Method). In samples having buffer capacity against acid, pH 1 (0.1 N HCl) of extraction solution can not be maintained and pH of extraction solution increases up to 8.0 when partial extraction in Standard Method is used. The averages and ranges of HPE(heavy metals extracted using partial extraction in Standard Method)/HPEM(heavy metals extracted using partial extraction method with maintaining 0.1 N of extraction solution) values are 0.479 and 0.145~0.929 for Cd, 0.534 and 0.078~0.928 for Zn, 0.432 and 0.041~0.992 for Mn, 0.359 and 0.011~0.874 for Cu, 0.150 and 0.018~0.530 for Cr, 0.219 and 0.003~0.853 for Pb, and 0.088 and 1.73${\times}$10$^{-5}$~0.303 for Fe. These data indicate that the difference between HPE and HPEM is large in the order of Fe, Cr, Pb, Cu, Mn, Cd and Zn. The amounts of heavy metals extracted decreases in the follow order; Sum III(sum of fraction I, II, III in sequential extraction)>HPEM>Sum III (sum of fraction I and II)>HPE for Zn, Cd and Mn and Sum III>HPEM>HPE for Cr and Fe. In the case Cr, Sum II is lower than HPEM and higher than HPE. In case of Cu, extracted heavy metals is large in the order Sum IV>HPEM>Sum III HPE. HPE/HPEM value decreases with increasing the amount of HCl used for maintaining 0.1 N of extraction solution. For samples with high buffer capacity, HPE/HPEM value in all elements is lower than 0.2. On the other hand, for samples with low buffer capacity, HPE/HPEM value are over 0.2 and many samples have values higher than 0.6 for Zn, Cd Mn and Cu due to the small difference between Sum II and Sum III, and relatively higher mobility. However, for Fe and Cr, HPE/HPEM value is below 0.2 even for samples with low buffer capacity due to their low mobility and big difference between Sum II and Sum III. This study indicates that the partial extraction method in Korean Standard Method of soil is not suitable for an assessment of soil contamination in area where buffer capacity of soil can be decreased or lost because of a long term exposure to environmental damage such as acidic rain.

• Journal of Environmental Health Sciences
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• v.26 no.4
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• pp.82-87
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• 2000

생물학적 슬러지를 대상으로 간헐포기 소화와 호기성 소화의 회분실험을 실시하였다. 생물학적 슬러지의 간헐포기 및 호기성 소화 초기단계에서 미생물의 감량은 주로 내생 호흡에 의해 이루어졌다. 이 단계에서 질소는 곧바로 용출되지 않고 슬러지내에 잔존함으로서 슬러지의 질소함량은 일시적으로 증가한다. 그러나 소화후반에서는 최초의 질소함량수준으로 다시 감소하였다. 34일간의 회분식 소화에서 호기성 소화의 총질소 제거효율은 0.1%로서 거의 제거가 안된 반면, 포기 비율 0.25, 05 및 0.75인 간헐포기 소화에서는 각각 42.7%, 42.5% 및 17.6%로 나타나 간헐포기 소화가 호기성 소화보다 질소 제거측면에서 우수하였다. VSS의 감소에 따라 슬러지내의 인도 수중으로 용출하였으나, 인 용출율은 VSS 감소율 보다 훨씬 낮았고 그 결과 소화슬러지의 인 함량은 지속적으로 증가하였다. 호기성 소화와 간헐포기 소화는 소화슬러지의 인 함량이 증가하는 공정이므로 반송수의 인 부하는 상대적으로 낮아지게 되고 이는 하수의 영양염류 제거측면에서 긍정적인 효과를 미칠 것으로 기대된다.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.4
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• pp.234-239
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• 2015

Various leaching tests were applied to the soil affected by accidental leakage of HF in an industrial area in Korea. Three different leaching methods including pH-stat, continuous batch leaching, and column tests were adopted to assess leaching characteristics and mobility of fluorine(F) in soil and the potential risks to ecosystem. Both natural and spiked samples were used for the leaching tests. F concentrations in the batch tests increased by leaching rapidly in the early stage of leaching and then maintained rather constant levels. Column leaching test also show similar result to that of the batch test. pH also controlled the leaching behavior of the soil. With increasing pH, more F was released in the pH-stat test. This is mainly due to the competition and exchange with hydroxyl ions, as pH increase to the alkaline range. Most of the F released by the accident seem to have removed in the very early stage of leaching, whereas some natural proportion from soil minerals are thought to have been released very slowly. Therefore, little F released during the accident remained, based on the results of this study on the samples after two years of the accident. We could conclude that soil contaminated by external effects such as chemical accidents should be managed immediately, especially with F.

• Journal of Biomedical Engineering Research
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• v.25 no.1
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• pp.11-19
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• 2004

Stage 1 sleep provides important information regarding interpretation of nocturnal polysomnography, particularly sleep onset. It is a short transition period from wakeful consciousness to sleep. Lack of prominent sleep events characterizing stage 1 sleep is a major obstacle in automatic sleep stage scoring. In this study, we attempted to utilize simultaneous EEC and EOG processing and analyses to detect stage 1 sleep automatically. Relative powers of the alpha waves and the theta waves were calculated from spectral estimation. Either the relative power of alpha waves less than 50％ or the relative power of theta waves more than 23％ was regarded as stage 1 sleep. SEM (slow eye movement) was defined as the duration of both eye movement ranging from 1.5 to 4 seconds and regarded also as stage 1 sleep. If one of these three criteria was met, the epoch was regarded as stage 1 sleep. Results f ere compared to the manual rating results done by two polysomnography experts. Total of 169 epochs was analyzed. Agreement rate for stage 1 sleep between automatic detection and manual scoring was 79.3％ and Cohen's Kappa was 0.586 (p＜0.01). A significant portion (32％) of automatically detected stage 1 sleep included SEM. Generally, digitally-scored sleep s1aging shows the accuracy up to 70％. Considering potential difficulties in stage 1 sleep scoring, the accuracy of 79.3％ in this study seems to be robust enough. Simultaneous analysis of EOG provides differential value to the present study from previous oneswhich mainly depended on EEG analysis. The issue of close relationship between SEM and stage 1 sleep raised by Kinnariet at. remains to be a valid one in this study.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1994.07a
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• pp.75-91
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• 1994

제주도의 지하수는 상위지하수, 기저지하수, 연안용출수, 심부지하수 등으로 분류될 수 있다. 이들을 효율적으로 활용하고 또 보존, 관리하기 위하여는 탐사가 선행되어야 한다. 구성물질의 물성대비를 탐사의 원리로 하는 물리탐사는 간접적 정보를 제공한다는 점에서 조사단계에서 흔히 간과되어 왔으나, 지표 상부에서 지하 심부까지의 정보를 제공할 수 있는 유일한 탐사방법이라는 점에서 그 중요성이 재인식되어야 한다. 물리탐사는 비파괴적인 탐사방법일 뿐 아니라 날은 탐사범위를 상대적으로 짧은 기간에 탐사할 수 있는 경제성을 갖고 있기 때문에 결과적으로 조사단계에서 소요되는 총비용을 현저히 줄일 수 있기 때문이다. 필자는 여기서, 제주도의 지하수문제에 대하여 물리탐사가 담당할 수 있는 역할에 대하여 최근의 탐사실례들을 통하여 기술하고자 한다. 이들 중에는 '복합 물리탐사방법에 의한 지하수탐사', '항공원격탐사에 의한 해안 용출수탐사', '물리탐사에 의한 해수침입영역 조사' 그리고 지하수 부존과 밀접한 관련이 있는 '지질구조선 탐사' 등이 포함되어 있다. 후속의 지질조사와 시추조사에서 얻은 직접적 정보들이 물리탐사에 의한 해석에 feedback 될 수 있는 조사체계를 갖춘다면 향후 제주도의 지하수와 관련한 문제에 물리탐사가 보다 효과적으로 사용될 수 있을 것임을 강조한다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.1
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• pp.71-82
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• 2017

It is necessary to conduct a detailed geotechnical investigation on the tunnel section in order to secure the tunnel design and construction stability. It is necessary for the importance of geotechnical investigation that needed for the analysis of distribution and size of fractured fault zone and distribution of groundwater in tunnel. However, if it is difficult to perform the ground survey in the tunnel design due to ground condition of the tunnel section and the limited conditions such as civil complaint, the tunnel design is performed using the result of the minimum survey. Therefore, if weathered fault zone exists in the face the reinforcement method is determined in the design process to secure the stability of the tunnel. The most important factor in reinforcing the tunnel excavation surface is to secure the stability of the tunnel by performing quick reinforcement. In particular, if groundwater leaching occurs on the excavation surface, more rapid reinforcement is needed. In this study, fractured fault zone exists on the tunnel excavation surface and displacement occurs due to weathered fracture zone. When the amount of groundwater leaching rapidly increased under the condition of displacement, the behavior of tunnel displacement was analyzed based on tunnel collapse. In the study, reinforcement measures were taken because the first stage displacement did not converge continuously. After the first reinforcement, the displacement was not converged due to increased groundwater leaching and the second stage displacement occurred and chimney collapse occurred.

• Journal of Chest Surgery
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• v.41 no.2
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• pp.202-209
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• 2008

Background: The introduction of Drug Eluting Stents (DES) decreased the number of patients referred for coronary artery bypass grafting (CABG). The impact of DES on CABG (Step 1) was studied and compared with the 1-year outcome after CABG with DES (Step 2). Material and Method: Surgical results for patients who underwent off-pump CABG (OPCAB) before the introduction of DES(n=298) were compared with those who underwent OPCAB after the introduction of DES (n=288) (Step 1). Postoperative 30-day and 1-year results were also compared between the patients who underwent percutaneous coronary intervention (PCI) using DES (n=220) and those who underwent OPCAB (n=255) (Step 2). Result: Since the introduction of DES, the ratio of CABG versus PCI decreased. In the CABG group, the number of high risk patients such as elderly patients (age 62 vs. 64, p=0.023), those with chronic renal failure (4% vs. 9%, p=0.021), calcification of the ascending aorta (9% vs. 15%, p=0.043), or frequency of urgent or emergent operations (12% vs. 22%, p=0.002) increased. However, there were no differences in the cardiac death and graft patency rates between the two groups (step 1). During the one-year follow up period, the rate of target vessel revascularization (12.3% vs. 2.4%, p<0.001) and major adverse cardiac events (MACE: death, myocardial infarct, TVR) were higher in the DES than the CABG group (13.6% vs 4.3%) (stage 2). Conclusion: Introduction of DES decreased the number of patients referred for surgery, and increased the comorbidity in patients who underwent CABG. DES increased the rate of target vessel revascularization, and the occurrence of MACE during the 1-year follow-up. However, there was no difference in the incidence of myocardial infarction and cardiac death between the two groups.

• Food Engineering Progress
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• v.13 no.4
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• pp.262-268
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• 2009

A dark brownish pigment in the crude polysaccharide from Auricularia auricula was adsorbed by activated charcoal. The leaching of the pigment adsorbed on activated charcoal and regeneration of activated charcoal used was investigated with eight kinds of solvents. The highest leaching capacity was obtained with the alkaline solution (KOH). The optimum volume of 1 M KOH solution per activated carbon was 45 mL/g, and the treatment for 10 min during single stage leaching was sufficient to achieve the leaching equilibrium. Second-order kinetic model provided the best fitting for the pigment leaching. The pigment leaching capacity of 88.9% was obtained by seven times of treatment with 1 M KOH solution at 25$^{\circ}C$, while at 95$^{\circ}C$, leaching capacity of 82.6% was achieved with single stage alone showing the significant increase of leaching capacity with increasing temperature. The regenerated activated charcoal was nearly as effective as fresh activated charcoal in pigment adsorption of crude polysaccharide from Auricularia auricula.

• The Journal of the Petrological Society of Korea
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• v.10 no.3
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• pp.133-147
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• 2001

Recently developing method of age determination using stepwise dissolution technique to expand the applicability of absolute age determination significantly is evaluated whether it is applicable to the Korean samples. The materials selected for the study are uranium-bearing black slates from Changni Formation of Ogcheon metamorphic belt, tourmaline separated from Naedeongni granite of Yeongnam massif, garnet and ilmenite separated from ilmenite-bearing anorthositic rock of Yeongnam massif, scheelites from Ogbang mine, and magnetite separated from Gyemyeongsan Formation of Ogcheon metamorphic belt. For the stepwise dissolution, various acid steps with different normalities and different durations were applied to leach the samples. The leachate from each step was analyzed to determine the Pb isotopic composition and concentrations of Pb and U using thermal ionization mass spectrometer. The black slates from the Changni Formation and the tourmaline from the Naedeongni granite reveal significant variation of Pb isotopic composition, which reveals the potential of such stepwise dissolution technique as a dating method. The behaviors of uranium and lead during the each stage of step leaching are different, which seem to reflect the differences in positions within the crystal lattices depending upon mineral species.

• Journal of Life Science
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• v.13 no.1
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• pp.67-72
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• 2003

Helicobacter pylori is the etiologic agent of human gastritis and peptic ulceration and produces urease as the major protein component on its surface. H. pylori urease is known to serve as a major virulence factor and a potent immunogen. Recombinant H. pylori urease expressed in E. coli was purified by simple purification procedures utilizing (CNBr-activated Sepharose-anti-urease IgG immunoaffinity chromatography or epoxy- activated Sepharose-urea affinity chromatography. Urease was apparently bound so tightly to the anti-urease IgG resin that it could not be eluted at various elution conditions except at certain extreme pH 1, including 100 mM carbonate (pH 10.5) buffer solution, which was shown to elute slightly inactivated but relatively pure enzyme. Urease eluted from the epoxy-activated Sepharose-urea affinity column showed higher activity, but the smaller UreA subunit of the enzyme appeared as a Fainter band of diminished intensity when subjected to SDS-polyamide gel electrophoresis.