• The Journal of the Petrological Society of Korea
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• v.17 no.4
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• pp.222-230
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• 2008

Intruding ages for the Jurassic(${\sim}Triassic$) granites in South Korea can be reestablished as $210{\sim}170\;Ma$ and $180{\sim}160\;Ma$ according to the tectonic provinces of magma emplacement. Most Jurassic granites in the Gyeonggi massif have the intrusion ages of $180{\sim}160\;Ma$, indicative of middle Jurassic igneous activity. On the other hand the intrusion ages ($210{\sim}170\;Ma$) for the Jurassic granites in the Yeongnam massif represent late Triassic to middle Jurassic igneous activity. Using the concept of granite suite/supersuite, the Jurassic granites in South Korea can be hierarchically divided into two supersuites and two suites. Huge batholith of NE-SW direction in the Gyeonggi massif could be designated to be 'Gyeonggi Supersuite', which was originated from the mixture of igneous protolith and more evoloved crustal materials and formed in the post-orogenic environment after collision of the north China and south China blocks. There are one supersuite and two suites in the Yeongnam massif 'Yeongnam Supersuite' could be designated from the NE-SW trend batholith in the massif. This supersuite was originated from the mixture of igneous protolith and evolved crustal materials. Granitic rocks between Andong and Girncheon areas could be defined as 'Andong Suite'. This suite was originated from the mixture of depleted mantle and igneous protolith. The Daegang and Hamchang granties could be designated as 'Daegang Suite'. This suite was formed in the anorogenic environment which was different from the orogenic environment of the other supersuite/suite in the Yeongnam massif.

• Korean Journal of Bronchoesophagology
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• v.3 no.2
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• pp.277-286
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• 1997

We have reviewed a 9-year experience with 47 patients treated for salivary tumors which arose In the parotid gland (23 patients; 48.9%), submandibular gland (15 Patients, 31.9%), minor salivary gland (8 patients; 17.0%), and sublingual gland (1 patient; 2.1%). The age of patients ranged from 12 to 71 with a mean of 42.9 years. The male to female ratio showed a female preponderance, 19:28 (1:1.5). An asymptomatic mass (91.5%) was most common presentation. With fine-needle aspiration, the predictive value of a neoplasm was 88.9%. Histopathologically, the most common salivary gland tumors was Pleomorphic adenoma(57.4%). The pleomorphic adenoma was most common in benign tumor group, and the mucoepidermoid carcinoma was most common in malignant tumor group. Of the salivary gland tumors, the incidence of cervical metastasis was 22.2%. Major postoperative complications were facial nerve paralysis and wound infection.

• Journal of Korea Water Resources Association
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• v.40 no.11
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• pp.861-867
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• 2007

This Research analyzes the consumers' willingness to pay(WTP) for residential water on severe drought condition. The 7 large cities and 32 chronicle drought regions have been selected for this research survey. Results show that the consumers of large cities, which are relatively rich, think water quality is more important than quantity, but the consumers of 32 chronicle drought regions expressed just opposite. Dichotomous choice and open-ended questionnaire are mixed for the survey and Tobit model is applied in the analysis. As we expected, the higher the education level, the number of household member, and the income, the higher the WTP. When there is 25% reduction of supply, the WTP is about $2 per month. Contrary to the expectation, WTP is just slightly increased for 50% of water supply reduction. This is because of the resistance of tax as well as the limited actual experiences of water shortage so, they underestimated it. In any cases, actual WTP for actual water shortage is much higher than this result. More effective water supply and distribution schedule must be ready as a national and local level to prepare severe drought in the near future. Consumers are willing to pay higher price than the current level for water security. Water distributional system should be reconsidered and alternative source of water also be prepared.

• Journal of the KSME
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• v.29 no.6
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• pp.573-580
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• 1989

현재 한국의 자동차 공업은 80년대 초반부터 급격한 발전으로 세계의 다른 자동차 생산국으로부 터 경계의 대상이 되고 있다. 그러나 그 내면을 살펴보면 아직도 중요한 기술은 거의 대부분 일 본이나 독일, 미국 등 자동차 선진국의 기술에 의존하고 있으며 특히 엔진 분야는 대부분 외국 기술에 의존하고 있다고 해도 과언이 아니다. 엔진은 자동차 생산원가의 약 30%를 차지하며 자동차의 성능을 좌우하는 경우 기술료 지급은 물론이며 부품구매 선택의 여지가 없어진다. 또한 요즈음과 같이 상품의 수명주기가 짧게 되어 가는 추세 하에서는 시장의 요구에 대처해나가는 엔지니어링 적응력이 부족하게 되면 결국 경쟁성을 상실하게 된다. 그러나 이러한 문제점을 인 식하면서도 80년대 초까지 독자적인 엔진개발을 하지 못했던 원인은 크게 2가지로 분석할 수 있다. 첫째는 한국의 자동차 회사들의 기술 축적의 미약과 둘째는 독자개발의 낮은 투자효율성 이다. 즉 엔진과 변속기를 기술 도입할 때 기술료 지급은 자동차 생산댓수당 5-6만원에 달하지만 엔진과 변속기를 독자개발시의 투자비는 약 300-500억원에 달하므로 간단한 산술적 계산으로는 모델당 100만대를 생산하여야만 투자의 가치가 있는 것으로 보여진다. 물론 위에서 언급한 바와 같은 여러 가지 요인에 의하면 이 숫자보다 훨씬 적은 생산량으로도 경쟁성이 확보될 것으로 예상된다. 이제 한국의 자동차 생산량도 연간 백만 대를 상회하는 수준이며 앞으로도 급격한 양과 질적인 팽창이 기대되고 있는 시점에 자동차 메이커들은 각사 모두 독자적인 고유 엔진 개발을 착수하였으며 일부 회사는 이미 성공을 거두어 양산 준비를 하고 있는 것으로 알고 있다. 그러나 아직도 엔진의 설계부터 양산까지 걸리는 기간이 타 선진 메이커에 비하면 상당히 길며 이로 인해 신제품의 경쟁력 저하가 우려되고 있는 상태이다. 이러한 문제점 해결에 도움을 주기 위해서 학계는 기업체의 기술 개발방향과 전략을 이해하는 것이 필요하다.grightarrow$cn-semistratifiable over$\longrightarrow$semistratifiable over $\alpha$ 2, 어떤 공간이 cn-Semistratifiable over $\alpha$이기 위한 필요충분 조건은 그것이 linearly cushioned cn-pairnet를 갖는 것이다. 3. cn-semistratifiable over $\alpha$의 부분공간 역시 cn-semistratifiabie over $\alpha$ 하다. 4. on-semistratifiable over $\alpha$의 유한개의 적공간 역시 cn-semistratifiabie over $\alpha$한다. 5. 폐 cn-semistratifiable over $\alpha$ 부분공간들의 합공간 역시 on-semistrbtifiable over $\alpha$ 하다. 6. 폐연속 net-cevering 함수에 의하여 cn-semistratifiable over $\alpha$ 성질이 보존된다. 보잘것이 없었고, 현재에도 각 시도별 또는 대학주관의 경시대회가 있으나 거국적인 호응을 받지 못했다. 물론 국제 대회에 참석시키는 것은 엄두도 내지 않았다.로 나타났다. 4. 코코넛과 소나무수피의 경우 암모니아 가스에 대한 흡착 능력은 거의 비슷한 것으로 사료되며, 코코넛의 경우 전량을 수입에 의존하고 있다는 점에서 국내 조달이 용이하며, 구입 비용도 적게 소요되는 소나무수피를 사용하는 것이 경제적이라고 사료된다. 5. 마지막으로 악취제거 미생물균주를 접종한 소나무수피 50%와 펄라이트 30%의 혼합재료를 24시간 동안 장기간 운전 실험을 수행한 결과 암모니아 99.06%, 황화수소 96.61%의 제거

• Journal of the Mineralogical Society of Korea
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• v.30 no.1
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• pp.11-19
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• 2017

Reddish brown clay-silt sediments covered granitoid weathering crust in the Jangdongri area, Naju, Korea. Mineralogical and geochemical properties of the ~2 m sediment section were investigated. The sediments were composed mainly of quartz (50%) and clay minerals (45%) with minor contents of K-feldspar, goethite, hematite, and gibbsite. The clay minerals were illite, illite-smectite mixed-layers, vermiculite, hydroxy-Al vermiculite, kaolinite, and halloysite. Mineral composition varied little through the section with the minor upward enrichment of plagioclase and chlorite. Abundant illitic clay minerals indicated the remote source of the sediments because clays derived by granite weathering in Korea were dominated by kaolin minerals. A comparison with the mineral composition of Asian dust (Hwangsa) suggested that plagioclase and K-feldspar disappeared by chemical weathering after deposition, resulting in the quartz and clay-rich sediments. Plagioclase and chlorite altered to kaolin and vermiculite, respectively. Goethite and hematite derived by the weathering of iron-bearing minerals stained the sediment to reddish brown color. The mineralogical and geochemical properties of the reddish brown clay-silt sediments were consistent with those of eolian deposits identified in Korea, supporting eolian origin of the Jangdongri sediments, requiring future confirmation including age dating and isotopic analysis.

• Journal of Life Science
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• v.15 no.4 s.71
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• pp.566-571
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• 2005

A natural habitat bacterium, Enterobacter cloaceae K41 was isolated from fresh water plant root and identified. This strain was used to investigate heavy metal resistance. The optimal growth conditions of the bacterium were LB medium containing$1\%$ yeast extract, $1\%$ lactose, $1\%$ NaCl, pH 7.0, at $37^{\circ}C$, and for 24 hours on a shaker. The minimal inhibitory concentration (MIC) of heavy metals against E. cloaceae KCTC2519 and E. cloaceae K41 was compared. The MIC of E. cloaceae K41 was 150 ppm in Cu, 50 ppm in Cd whereas that of the standard strain was 50 ppm in Cu but no growth was observed either Cd or two mixed heavy metal solution. The presence of plasmid was cleared from the isolated strain whereas no possession from the standard strain. The plasmid from E. cloaceae K41 was transformed into E. coli $DH5{\alpha}$. The MIC of transformed strain increased resistance 7 times in Cu and 6 times in Cd by insertion of this plasmid. The metal adsorption of the transformant was increased 1.3 times in Cu and 1.5 times in Cd indicating the plasmid was responsible for heavy metal resistance.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 1998.05a
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• pp.108-108
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• 1998

일반적으로 탄소강은 수용액 중에 노출될 경우 전면부식에 의한 손상을 받는다. 그러나 부식방지를 위하여 부식억제제를 적용할 경우, 탄소강의 부식거동은 현저한 변화를 겪게된다. 이러한 부식거동의 변화는 첨가되는 부식억제제의 종류에 따라 분 류할 수가 있는데, 양극부식억제제, 음극부식억제제 그리고 이들의 혼합부식억제제로 분류할 수가 있다. 현장에 적용된 부식억제제 시스템 중에는 자동차용 부동액과 가스히터용 열전달 매체액이 있다. 이러한 부식억제제가 적용된 시스댐은 정확한 부식억제능의 평가에 의한 그 교체 시기의 결정이 매우 중요하다. 교체 시기가 빠를 경우, 유지비용이 과다하게 소요되는 문제가 있으며, 교체시기가 늦을 경우 설비의 부식을 초래하는 문제 가 있다. 따라서 부식억제제의 정확한 성능 평가법은 매우 중요하며, 이에 대한 다양 한 연구가 진행 중이다. 부식억제제가 함유된 용액의 부식억제성능을 평가하는 방법에는 대표적으로 무게 감량법을 이용하고 있다. 이 방법은 다종의 금속이 적용된 자동차용 부동액을 실제 사용조건과 유사한 실험 조건에서 단기간, 가혹조건에서의 무게 감량에 의해 부식억 제능을 평가하는 방법이다. 그러나 이러한 방법은 특히 국부부식이 진행될 경우 부 식억제능을 정량화 하는데 어려움이 있다. 한편 전기화학적 측정방법으로는 분극곡선법을 이용한 $E_P$(공식개시전위), $E_R$(재부동태 화전위)의 측정법이 있다. 또한 부식억제피막의 안정성을 측정하기 위한 방법으로 인 위적인 양극전류 인가에 의한 피막의 파괴후에 피막이 복원가능 여부 및 그 속도 측 정에 의해 부식억제제의 건전성을 확인할 수가 었다. 본 연구에서는 가스히터의 주구성 재료인 A210 Gr Al의 탄소강을 사용하여, 사용기간이 5년 이상되어 부식억제 기능을 거의 상실한 것으로 여겨지는 열전달 매체액 과 신규 부식억제제가 적용된 시스템 등 객관적으로 확인된 부식억제제 시스랩에 대 하여 다양한 평가 방법을 동원 비교분석하고자 하였다. 실험은 KSM 2142에 의한 무게감량법, 분극곡선 측정에 의한 $E_P$(공식개시전위), $E_R$(재부동태화전위) 측정, 시간에 따른 자연전위 변화 측정 빛 이때의 부식속도(선형분극법), 인위적인 피막 파괴 전,후 의 전위 변화 및 부식속도 측정법에 의한 국부부식 발달 저지능 등을 평가하여 각 실험결과를 비교분석하여 보았다.

• Journal of the Korean Institute of Intelligent Systems
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• v.12 no.3
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• pp.210-218
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• 2002

This paper proposes an efficient separation method of the composite images by using independent component analysis(ICA) based on neural networks of the approximate learning algorithm. The Proposed learning algorithm is the fixed point(FP) algorithm based on Secant method which can be approximately computed by only the values of function for estimating the root of objective function for optimizing entropy. The secant method is an alternative of the Newton method which is essential to differentiate the function for estimating the root. It can achieve a superior property of the FP algorithm for ICA due to simplify the composite computation of differential process. The proposed algorithm has been applied to the composite signals and image generated by random mixing matrix in the 4 signal of 500-sample and the 10 images of $512{\times}512-pixel$, respectively The simulation results show that the proposed algorithm has better performance of the learning speed and the separation than those using the conventional algorithm based method. It also solved the training performances depending on initial points setting and the nonrealistic learning time for separating the large size image by using the conventional algorithm.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.11
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• pp.1192-1197
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• 2006

Adsorbability of ionic and nonionic pharmaceuticals was studied using granular activated carbon(GAC). In a batch adsorption test of muticomponent solution, 500 mg/L of GAC dose removed all target compounds between 94 and 98% at initial concentration of 10 ${\mu}g/L$. Adsorption of ionic pharmaceuticals increased as pH was lowered toward to pKa, however adsorption capacity of nonionic pharmaceuticals showed insignificant variation with the changing pH. The enhanced adsorption capacity of ionic pharmaceuticals at lower pH was attributed to the corresponding increase in the molecular form of ionic pharmaceuticals with carboxylic group at low pH. In addition, decrease of pH increased hydrogen ion concentration in the bulk solution and the protons bound to the available sites on the carbon enhanced the removal of the ionic pharmaceuticals from solution. After 40 days of continuous operation, GAC column showed the removal of target compounds were removed by $93{\sim}99%$ at 15 min of EBCT mainly due to adsorption mechanism of GAC. At shorter EBCT than 15 min, breakthrough of CA, IBP and GFZ occurred earlier than the other ionic and nonionic pharmaceuticals. effect of EBCT on adsorption of nonionic pharmaceuticals was greater than ionic ones. This study showed that persitent pharmaceuticals found in drinking water treatment could be effectively controlled by adsorption in GAC process.

• Journal of the Korean Society for Marine Environment & Energy
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• v.5 no.1
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• pp.51-67
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• 2002

In order to understand behaviors of heavy metals around the artificial Lake Shihwa in the vicinity of Kyunggi Bay in Korea in relation with huge environmental changes due to construction of huge artificial lake, water samples were collected from Lake Shihwa and its tributaries from 1996 to 1998 and analyzed. Due to extreme pollutant discharge from various kinds of anthropogenic sources such as the Banweol and Shihwa Industrial Complexes and cities, the Shihwa and its tributaries have been polluted in waters with various heavy metals. The enrichment factors of particulate heavy metals in water of streams and storm sewers were very high. All of the heavy metals observed in the waters showed relatively high temporal and spatial variations. In surface waters of the lake during the desalination after the dike establishment, spatial distributions of heavy metal concentrations were mainly controlled by various biogeochemical factors as well as input of industrial and municipal wastewaters, while, physical mixing was minor factor Pb and Co showed a strong affinity to particle phase, however the affinity to dissolved phase was dominated in Ni, Cu and Cd. Water quality of the artificial Lake Shihwa has been deteriorated by direct discharge of untreated wastewater and heavy metals have been accumulated in the lake system. Therefore, luther environmental improvement plan should be programmed subsequently.