• Journal of Korean Society of Forest Science
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• v.105 no.4
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• pp.401-413
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• 2016

Forest resources utilization and variable disturbance history have been affected the rarity and conservation value of forest relict trees, which served as habitat for forest biodiversity, important carbon stock and cultural role include human and natural history in South Korea. This study was conducted to establish the baseline data for forest resources conservation by clarifying species diversity, spatial distribution and ecological characteristics (individual and habitat) of forest relict trees (DBH > 300 cm) based on the data getting from mountain trail, high resolution aerial photos and field professionals and field survey. As results, 54 taxa (18 family 32 genus 48 species 1 subspecies 3 variety and 2 form) as about 22% of tree species in Korea was identified in the field. 837 individuals of forest relict trees were observed and the majority of the trees was in Pinaceae, deciduous Fagaceae and Rosaceae, which families are abundant in population diversity. High elevation area was important to relict trees as mean altitudinal distribution was 1,200 m a.s.l as likely affected by human activity gradients and mid-steep slope and North aspect was important environment for the trees remain. Many individuals exhibited 'damage larger branch' (55.6%) and consequent relatively lower mean canopy coverages (below 80%). Synthetically, present diversity and abundance of relict forest trees in South Korea were the result of complex process among climate variation, local weather and biological factors and the trees of big and old were estimated to important forest biodiversity elements. In the future, clarifying the role and function of relict trees in forest ecosystem, in- and ex- situ programmes for important trees and habitat, and activities for building the background of conservation policy such as "Guideline for identifying and measurement of forest relict trees".

• The Journal of Information Technology
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• v.1 no.2
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• pp.81-102
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• 1998

It is common description that modern society is In the era of limitless competition. In order to challenge the change of economy and its management at home and abroad, organization should be changed anew, and in this case, there accompanies conflict or trouble whether the subject of change wants it or not. Therefore, according to change, we should concern with settlement of small troubles as well as big ones, and by managing the conflict or trouble productively and originally, it should be utilized as new fatality and chance to develop something in organization. In the system organized by people, there exist various conflicts in accordance with the target and want of the system, therefore giving no freedom to each Individual member of the system, and this is an unavoidable tate in consideration of the modem society where the survival of mankind and human systems should be guaranteed. Therefore, it determines the coordinates of success of any of organizations to manage conflict or trouble well, and so, when decreasing or increasing conflicts so that the organization exerts its full influence, it is note worthy that conflict itself should be rationally and efficiently managed. In a view point of the theory of organization and its behavior, relating job satisfaction with the performance and validity of organization, the influence of individual conflict is so great on the rate of job transfer within an organization or nonattendance, even on the productivity of the organization. So, the manager to cope with conflict within an organization should devise following three plans to manage conflict for job satisfaction and conflict settlement. In conclusion, it is suggested that in order to manage conflict within an organization well, some plans to control conflict should be well utilized while giving more efforts to improving management of individual conflict, job satisfaction, validity of organization, productivity, etc and all the members of organization should remember that the Issue of conflict within an organization be recognized ad an opportunity of new development and a way to settle a trouble within an organization, and a direction of conflict management should be suggested so that new innovation ca be created.

• Applied Biological Chemistry
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• v.44 no.2
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• pp.73-80
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• 2001

Factors such as temperature $(20,\;60^{\circ}C)$), pH (4.5, 7.0), gaseous phase $(N_2,\;0_2)$, and light (0 lux, 5,000 lux), antioxidants and packaging conditions were investigated to study the effects of above factors on the chlorophyll components in spinach during storage. Regardless of other factors, as the storage temperature increased from $20^{\circ}C$ to $60^{\circ}C$ and pH decreased from 7.0 to 4.5, the contents of chlorophyll a and chlorophyll b in spinach decreased significantly (P<0.05). The amounts of chlorophyll a and chlorophyll b in spinach stored in nitrogen gas were significantly (P<0.05) lower than those in sample in oxygen phase. As the light intensity increased from 0 lux to 5,000 lux during storage, the contents of chlorophyll a and chlorophyll b in spinach significantly (P<0.05) decreased. The antioxidants reduced the degradation of chlorophyll a in a model system during dark storage by minimization of free radical oxidation. The effectiveness of antioxidants decreased as following orders; ${\alpha}-tocopherol$>ascorbic acid>${\beta}-carotene$>catechin>quercetin>rutin>kaempherol>caffeic acid>chlorogenic acid>p-coumaric acid>ferulic acid. The degradation of chlorophyll a in a model system during light storage was minimized by antioxidants due to the reduction of singlet oxygen oxidation. The antidiscoloring potential of antioxidants decreased as following orders; ${\beta}-carotene$>${\alpha}-tocopherol$>ascorbic acid>catechin>quercetin>rutin>kaem-pherol>caffeic acid>chlorogenic acid>p-coumaric acid>ferulic acid. The amounts of chlorophyll a and chlorophyll b in freeze dried spinach packed with polyethylene bag were significantly (P<0.05) lower than those in non-packed freeze dried spinach. The package of spinach in polyethylene bag with the combination of antioxidants could be used to minimize the degradation of chlorophyll components in spinach during storage.

• Radiation Oncology Journal
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• v.16 no.3
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• pp.251-258
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• 1998

Purpose : This study was performed to analyze the factors affecting local control in malignant tumors of the parotid gland treated with surgery and postoperative radiation. Materials and methods : Twenty-six patients were treated for malignant tumors of the parotid gland from 1986 to 1995 at Department of Therapeutic Radiology, Chonnam University Hospital. Age of the patients ranged from 14 to 72 years (median : 55 years). Histologically 10 patients of mucoepidermoid carcinoma, 7 of squamous cell carcinoma, 4 of acinic cell carcinoma, 4 of adenoid cystic carcinoma and 1 of adenocarcinoma were treated. Total parotidectomy was performd in 15 of 26 patients, superficial in 7, subtotal in 4. Facial nerve was sacrificed in 5 patients. Postoperatively 4 patients had residual disease, 4 had positive resection margin. Radiation was delivered through an ipsilateral wedged pair of photon in 11 patients. High energy electron beam was mixed with photon in 15 patients. Electron beam dose ranged from 900 cGy to 3800 cGy (median 1700 cGy). Total radiation dose ranged from 5000 cGy to 7560 cGy (median : 6020 cGy). Minimum follow-up period was 2 years. Local control and survival rate were calculated using Kaplan-Meier method. Generalized Wilcoxon test and Cox proportional hazard model were used to test factors affecting local control. Results : Five (19$\%$) of 26 patients had local recurrence. Five year local control rate was 77$\%$. Overall five year survival rate was 70$\%$. Sex, age, tumor size, surgical involvement of cervical lymph node, involvement of resection margin, surgical invasion of nerve, and total dose were analyzed as suggested factors affecting local control rate. Among them patients with tumor size less than 4 cm (p=0.002) and negative resection margin (p=0.011) were associated with better local control rates in univariate analysis. Multivariate analysis showed only tumor size factor is associated with local control rate (p=0.022). Conclusion : This study suggested that tumor size is important in local control of malignant tumors of parotid gland.

• Tuberculosis and Respiratory Diseases
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• v.44 no.6
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• pp.1234-1244
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• 1997

Background : Nowadays drug resistant tuberculosis is making problems in the treatment of pulmonary tuberculosis and its number is increasing. Several reasons for this are considered including irregular medication, poor drug compliance and wrong regimens. But there are treatment failure cases in spite of regular medication with short-term standard regimens. We reviewed clinical data of 50 patients to find out possible causes of this. Method : Subject of this study was 50 patients who failed in the primary treatment of pulmonary tuberculosis in spite of regular medication with short-term standard regimens. All of them were under treatment with secondary regimens in National Masan Tuberculosis Hospital on Oct 1996. The patient's records were analyzed retrospectively and direct interviews with patients were done. Results : There were relatively more patients in the age of 20th. Male overwhelmed in number. There were smoking in 22 patients and drinking in 24 patients during medication. 17(34%) patients had family history of tuberculosis. Public health center was the most common site for the initial diagnosis among medical institutes. 42 patients had subjective symptoms for pulmonary tuberculosis. 38 patients got sufficient explanation from medical institute about tuberculosis and medication courses. 24 patients had bilateral lesions on chest X-ray film and 43 patients had cavitary lesions. 29 patients had past history for pulmonary tuberculosis with regular medication. The results of drug sensitivity test showed resistance in 41 patients of whom we could get the results. Conclusion : Main cause of treatment failure of pulmonary tuberculosis in spite of regular medication with short-term standard regimens was drug resistance. Several factors were considered to be related to high prevalence of drug resistance, including age of 20th, male, family history for tuberculosis, bilateral lesions or remaining cavitary lesion on chest X-ray film.

• Korean Journal of Environmental Biology
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• v.40 no.4
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• pp.455-463
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• 2022

To understand functional changes of forest ecosystems due to climate change, correlation between decomposition rate of leaf litter, an important function of forest ecosystems, and microclimatic factors was analyzed. After 48 months elapsed, percent remaining weight of Quercus mongolica leaf litter was 27.1% in the east aspect and 37.0% in the west aspects. Decay constant of Q. mongolica leaf litter was 0.33 in the east aspect and 0.25 in the west aspect after 48 months elapsed. Initial C/N ratio of Q. mongolica leaf litter was 38.5. After 48 months elapsed, C/N ratio of decomposing Q. mongolica leaf litter decreased to 13.43 in the east aspect and 16.72 in the west aspect. Average air temperature and soil temperature during the investigation period of the research site were 8.2±9.0 and 9.1±9.3 in the east and 8.5±7.4 and 9.3±7.3℃ in the west aspect, respectively, with the west aspect showing higher air and soil temperatures. Soil moisture showed no significant difference between east and west aspects (average soil moisture: 19.4±11.0% vs. 20.5±5.7%). However, as a result of analyzing the correlation between decomposition rate and microclimatic factors, it was found that the decomposition rate and soil moisture has a positive correlation(r=0.426) in the east aspect but not in the west aspect. Our study shows that the correlation between decomposition rate and microclimatic factors can be significantly different depending on the direction of the aspect.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.197-197
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• 2010

음식물쓰레기의 삼성분은 수분, 휘발분, 회분이며 이들이 차지하는 비율은 계절, 지역별로 다소 상이하지만 수분 약 80%, 회분3%, 휘발분 17%이다. 음식물쓰레기 전처리과정으로 이물질제거, 탈수공정이 있으며 탈수공정에서 다량의 탈리액이 발생한다. 본 연구에서는 탈리액을 데칸타를 이용하여 1차로 원심분리하여 고.액 분리한 액을 실험대상으로 하였다. 실험대상 탈리액의 물성은 BOD 78,800[mg/l], COD 41,000[mg/l], 부유물질 25,900[mg/l], 총질소 928[mg/l]이었다. 탈리액에는 기름성분(육류, 식용유등), 입자상물질등이 포함되어 있으며 이들은 난분해성 유기물질로, 이를 제거하는데 기존의 처리방법으로 많은 어려움이 있어 주요한 수질오염 발생원이 되고 있다. 예를들면 하수처리장 폭기조 수면에 유막을 형성하여 산소공급을 방해함으로 미생물번식을 방해하는 요인이 된다. 본 연구는 음식물쓰레기 탈리액의 수분, 고형분, 유분으로의 삼상분리에 관한 것이다. 유분은 에멀젼형태로 안정되게 수층에 분산되어 존재한다. 미세기포를 이용한 부상법의 경우 미세기포 표면과 유분의 화학적친화력이 낮아 기포표면에 유분이 잘 부착되지 않으며, 원심분리 방법만으로는 유분 분리효율이 낮고, 추출에 의한 분리시 추출액이 다량 소요되고 처리시간이 길며 추출액 비용이 많이 소요된다. 탈리액을 유분, 슬러지, 수분으로 분리하면 환경오염을 일으키는 주요성분을 신재생에너지 원료로 활용할 수 있다. 유분의 주성분이 동식물성 유지이므로 전처리시 산촉매를 이용 수분과 유리지방산을 제거하고 염기성촉매를 이용하여 전이에스테르화 반응을 거치면 바이오디젤인 FAME과 글리세롤으로 변환하므로 글리세롤을 분리하면 바이오디젤을 얻을 수 있다. 슬러지는 입자상 물질로 착화가 잘 되고 건조하면 발열량이 높으며 중금속등에 오염되지 않아 청정연료로 활용이 가능하다. 실험실에서의 탈리액 삼상분리방법은 다음과 같다. 탈리액 30ml당 추출액으로 노말헥산을 1ml를 가한 다음 플라스크에서 $80^{\circ}C$로 가열 후 방냉한다. 가열중 노말헥산의 손실을 방지하기 위하여 증발가스를 콘덴서에서 응축하여 플라스크로 재순환한다. 탈리액을 플라스크에서 꺼내어 원심분리기 rack에 300-400g씩 병에 각각 넣고 4,000rpm으로 30분간 운전한다. 탈리액은 상부로부터 유분층, 미세입자층, 수층, 슬러지층으로 분리된다. 각 층의 계면에서 2종의 성분이 약간 섞일 수 있다. 유분을 분리한 후 유분층 잔존물과 미세입자층, 수층 상층부의 혼합물을 취하여 50g씩 병에 넣고 3,500rpm으로 10분간 운전한 후 유분을 분리한다. 마지막으로 미세입자층만을 3,500rpm으로 10분간 원심분리한 후 유분을 따로 분리한다. 얻어진 유분은 rotary evaporator에서 $120^{\circ}C$로 가열하여 유분과 노말헥산을 분리하며 분리효율을 제고하기 위하여 감압하에서 운전한다. 분리된 유분의 고위발열량이 9,450[Kcal/kg]이었으며 원소분석 결과 탄소 74.7%, 수소 12.55%, 질소 0.08%, 유황분 0.0003%이었다. 분리된 유분의 양은 계절별로 시료별로 다르며 가을철에는 1.6-1.9%, 여름철은 1.0-1.3%이었다. 분리된 슬러지로부터 Hg, As, Cr, Cd, Pb 중금속 성분이 검출되지 않았으며 수분 2.8%, 휘발분 76.85%, 회분 7.52%, 고정탄소 12.83%이었고 원소분석결과 탄소 45.25%, 수소 7.46%, 질소 5.05%, 산소 34.39%, 유황분 0.33%이었으며 저위발열량은 4,480[Kcal/kg]이었다. 분리된 슬러지 양은 11-19% 이었다.

• Journal of the Korea Concrete Institute
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• v.15 no.1
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• pp.25-34
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• 2003

The degradation of reinforced concrete (RC) structures due to physical and chemical attacks has been a major issue in construction engineering. Deterioration of RC structures by chloride attack followed by reinforcement corrosion is one of the serious problems. An objective of this study is to develop a form of mathematical model of chloride ingress into concrete. In order to overcome some limits of the previous approaches, a chloride ingress model, consisting of chloride solution intrusion through the capillary pore and chloride ion diffusion through the pore water, was proposed. Moreover, the variability of chloride ion diffusivity due to the degree of hydration of cement, relative humidity in pore, exposure condition, and variation of chloride binding, was considered in the model. In order to verify the proposed model, the results predicted by the proposed model were compared with analysis results of Life-365, a computer program for predicting the service life of reinforced concrete structures exposed to chlorides. In conclusion, the proposed model would be promising to predict the chloride ion profile and to estimate the service life of RC structures.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.5
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• pp.312-320
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• 2013

Particulates in drinking water distribution system (DWDS) are mostly influenced by internal corrosion of metal pipes and sediment in pipelines due to the solution of this effect is limited. The particle size, component and properties of compounds for particulates in distributed water are different and the difference of these characteristics will be occurred by the kind of facilities, pipe condition, external factors and supply system etc. In this study, conducting the investigation of water quality in DWDS researches with particulates in the water. Monitoring sites were each water supply reservoir and the end of water supply area in DWDS. To collect particulate material at each sampling site, $47{\phi}$ glass microfiber filter type GF/C was performed using a filtration. Substances that the effect of the turbidity in the water according to particulate suspended solids and inorganic materials is due to the increasing particulates in the end of DWDS were increased. The result of compounds analysis by using X-ray diffraction (XRD) were Goethite (${\alpha}$-FeOOH), Magnetite ($Fe_3O_4$) in the end of DWDS and Quartz ($SiO_2$), Yeelimite ($Ca_4Al_6O_{12}SO_4$) at the effluent of waterworks and reservoirs. There were differences the compounds and sediments in the releasing or remaining water distribution facilities.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.2
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• pp.91-97
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• 2005

We investigated the question whether protein removing activities of enzyme cleaner - protein remover for soft contact lens - are associated with the material of soft contact lens as well as action time, temperature and pH of enzyme solution. We used a subtilisin cleaner as protein remover and estimated the protein amount remained on soft contact lens after using the subtilisin cleaner under the different conditions. The remained protein in soft contact lens was greatly decreased until treatment for 60min, but no significant differences were found from 60min to 24hr. The cleaning effect of the enzymatic treatment in the range of $15{\sim}30^{\circ}C$ was constant. however, there was a significant decline of the protein removing effect at $10^{\circ}C$ and less. The pH of the solution was also important for the efficacy of the enzymatic treatment. The activity of the enzyme cleaner was highest in pH 8.0 and significantly decreased a pH below 7. The pH dependence was found to be related to the conformational change of subtilisin. Furthermore, significant differences in the protein deposit removing efficacy of the subtilisin cleaner were found among the soft contact lens materials.