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Mechanism of Biological Nitrogen Fixation in Azotobacter vinelandii (Azotobacter vinelandii에서의 생물학적 질소고정 작용 메카니즘)

  • Kim, Yong-Ung;Han, Jae-Hong
    • Applied Biological Chemistry
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    • v.48 no.3
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    • pp.189-200
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    • 2005
  • Biological nitrogen fixation is an important process for academic and industrial aspects. This review will briefly compare industrial and biological nitrogen fixation and cover the characteristics of biological nitrogen fixation studied in Azotobacter vinelandii. Various organisms can carry out biological nitrogen fixation and recently the researches on the reaction mechanism were concentrated on the free-living microorganism, A. vinelandii. Nitrogen fixation, which transforms atmospheric $N_2$ into ammonia, is chemically a reduction reaction requiring electron donation. Nitrogenase, the biological nitrgen fixer, accepts electrons from biological electron donors, and transfers them to the active site, FeMo-cofactor, through $Fe_4S_4$ cluster in Fe protein and P-cluster in MoFe protein. The electron transport and the proton transport are very important processes in the nitrogenase catalysis to understand its reaction mechanism, and the interactions between FeMo-cofactor and nitrogen molecule are at the center of biological nitrogen fixation mechanism. Spectroscopic studies including protein X-ray crystallography, EPR and $M{\ddot{o}}ssbauer$, biochemical approaches including substrate and inhibitor interactions as well as site-directed mutation study, and chemical approach to synthesize the FeMo-cofactor model compounds were used for biological nitrogen fixation study. Recent research results from these area were presented, and finally, a new nitrogenase reaction mechanism will be proposed based on the various research results.

The Effects of Ca and Mg Supplementation on Serum and Liver Lipid Parameters in Ovariectomized and Ca Deficiency Rats (난소절제 칼슘결핍 흰쥐에서 칼슘과 마그네슘의 보충이 혈액과 간의 지질함량에 미치는 영향)

  • Bae, Yun-Jung;Kim, Mi-Hyun;Sung, Chung-Ja
    • Journal of Nutrition and Health
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    • v.40 no.7
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    • pp.616-623
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    • 2007
  • This study was carried out to investigate the Ca and Mg supplementation on the serum and liver lipid parameters in ovariectomized and Ca deficiency rats. Total 50 Sprague Dawley female rats (6 weeks) were divided into 5 groups and bred for 12 weeks: sham operated control group (SNCa), OVX Ca deficiency poop (OLCa) with Ca deficiency diet (0.1% Ca modified AIN-93N diet), OVX Ca deficiency & Mg supplement group (OLCaMg), OVX adequate Ca group (OACa; 0.5% Ca AIN-93N diet) and OVX adequate Ca & Mg supplement group (OACaMg). There were no significant difference among the five groups in serum total cholesterol, triglyceride and HDL-cholesterol levels. LDL-cholesterol of OVX groups was significantly higher than that of SNCa group (p < 0.01). AI (Atherogenic index), TPH (Total cholesterol/HDL-C) and LPH (LDL-C/HDL-C) of OACa group were significantly lower than those of OLCa groups. OACaMg group had significantly lower levels LDL, AI and TPH than OLCa group. There was no significant difference in lever cholesterol level. However, liver total fat content of OACa was significantly lower than that of OLCa. From the above the results, it is concluded that the accumulation level of calcium shows how the supplement of magnesium affects hyperlipidemia. Therefore, in order to prevent women#s hyperlipidemia after menopause, and to keep healthy, it is encourage able to consider how the supplement of magnesium relates calcium intake.

Studies on lead uptake by crops and reduction of it's damage. -IV. Effects of application of calcium and phosphate materials on lead uptake by upland crops (농작물(農作物)에 대(對)한 납(Pb)의 흡수(吸收) 및 피해경감(被害輕減)에 관(關)한 연구(硏究) -IV. 밭작물(作物)의 납 흡수이행(吸收移行)과 석회(石灰) 및 인산(燐酸)의 영향(影響))

  • Kim, Bok-Young;Kim, Kyu-Sik;Han, Ki-Hak
    • Korean Journal of Soil Science and Fertilizer
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    • v.21 no.4
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    • pp.426-433
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    • 1988
  • A pot experiment was conducted to find out the effects of application of slacked lime and fused super-phosphate on the lead uptake of upland crops in a lead added soil. Lead concentration of the soils were adjusted to 0, 150, 300mg/kg respectively. The slacked lime was applied at the equivalent amount of lime requirement with extra 150kg/10a, and 2 times for the fused superphosphate. The results obtained were as follows: 1. Lead contents in crops increased in the order: sesame > maize > potato > sweet potato > soybean > green perilla > peanut > red bean. 2. Lead contents in parts of crops were increased in the order; root > stem > leaf > grain. 3. Increasing lead concentration in soils, lead content in the plant was increased and crops yield were decreased. 4. Lead contents in soybean and green perlilla were decreased in slacked lime application treatment. 5. The lead contents in leaf and grain of soybean and green perllila decreased with decreasing in the ratio of Pb/Ca+Mg equivalent in soil. 6. Grain yield were increased in slacked lime, but were decreased in fused superphosphate application treatment. 7. With increasing the soil Pb contents, calcium and phosphate contents were increased in leaf and stem, but calcium was decreased in roots. 8. $1N-NH_4$ OAC soluble Pb contents in soil were 26-50 ppm and 42-70 ppm, respectively, for 150mg/kg and 300mg/kg lead treatments. 9. The soil pH was increased in the order of slacked lime, fused superphosphate and nontreatment.

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Effect of Breathable Film for Modified Atmosphere Packaging Material on the Quality and Storability of Tomato in Long Distance Export Condition (MAP 포장재인 숨쉬는 필름이 장거리 수출 조건에서 토마토의 품질과 저장성 향상에 미치는 영향)

  • Islam, Mohammad Zahirul;Kim, Young-Shik;Kang, Ho-Min
    • Journal of Bio-Environment Control
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    • v.20 no.3
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    • pp.221-226
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    • 2011
  • The study was carried out to investigate the effect of MA packaging materials on quality and storability of tomato in long distance export condition. We found that the fresh weight loss in perforated film was higher than other breathable films. The fresh weight of tomato (cv 'Madison') packaged with breathable films, such as 5,000 cc, 10,000 cc, $20,000cc/m^2{\cdot}day{\cdot}atm$ oxygen permeable films, reduced less than 0.6%, but perforated film that already being used for packaging horticultural crops showed 1.4% fresh weight loss during $5^{\circ}C$ storage for 20 days and then $20^{\circ}C$ storage for last 5 days with 85% relative humidity. The carbon dioxide and oxygen concentration in tomato packages showed proper level for MA storage in $20,000cc/m^2{\cdot}day{\cdot}atm$ $O_2$ breathable film treatment at $5^{\circ}C$ storage. Although at $20^{\circ}C$ storage, the carbon dioxide concentration increased sharply, the oxygen concentration decreased remarkably, the change of these gases concentration was the lowest in 20,000 cc film treatment. The ethylene concentration was sharply increased at $20^{\circ}C$ from $21^{st}$ day to $25^{th}$ day after $5^{\circ}C$ storage for 20 day, and the concentration was lower in 20,000 cc film treatment among the breathable film treatments. Until 20 days, at $5^{\circ}C$ storage all treatments did not exceed the marketability. However, the last 5 days during at $20^{\circ}C$, the fruit appeared fungal rots and the quality rapidly decreased. The $20,000cc/m^2{\cdot}day{\cdot}atm$ $O_2$ permeability treated tomato performed higher firmness (9.56 N), vitamin C (16.31 mg/100 gFW), and soluble solids ($7^{\circ}Brix$) than other breathable films at final storage day. The results suggest that the $20,000cc/m^2{\cdot}day{\cdot}atm$ $O_2$ permeable film treatment of tomato (cv 'Madison') performed the highest quality and storability of tomato for long distance exporting.

Endocrine Function and Growth in Children with Craniopharyngioma (소아 두개인두종 환자에서 치료 전후의 뇌하수체 기능과 성장 및 체중 변화)

  • Chung, Yoo Mi;Shin, Choong Ho;Yang, Sei Won
    • Clinical and Experimental Pediatrics
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    • v.46 no.3
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    • pp.277-283
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    • 2003
  • Purpose : Craniopharyngiomas are often accompanied by severe endocrine disorders. Although there is universal growth hormone deficiency(GHD), the resulting growth pattern is very heterogeneous. We report the growth and endocrine outcome of 44 children with craniopharyngioma, with emphasis on initial symptoms, growth before and during growth hormone(GH) treatment and spontaneous growth in spite of GHD. Methods : We performed a retrospective study of 44 children treated at our centre between 1984 and 2002. Results : About 30% of patients had symptoms suggesting endocrine disorder at diagnosis. After surgery, multiple endocrinopathies were almost universal. Before GH therapy, height velocity was $8.00{\pm}2.71cm/yr$ in the normal growth group(n=11) and $1.79{\pm}1.10cm/yr$ in the subnormal growth group(n=7) during the first year and during the second year, $6.76{\pm}2.49cm/yr$ and $2.29{\pm}1.33cm/yr$, respectively. There was no difference of body mass index(BMI) change between before and after surgery in the two groups. Height standard deviation score(SDS) was $-1.46{\pm}0.74$ in the normal growth group and $-0.43{\pm}0.97$ in the subnormal growth group. Before GH treatment height SDS was $-1.31{\pm}1.25$ and BMI was $20.46{\pm}3.60$. During GH treatment, height SDS increased to $-0.60{\pm}1.37$ in the first, and to $-0.41{\pm}1.54$ in the second year(P<0.05), but BMI did not change significantly. Conclusion : The endocrine morbidity could develop in most children with craniopharyngioma before and after the operation and should be managed properly. Although all treated patients benefit from GH therapy, further studies are necessary to find out the possible mechanism of growth regulation in normally growing children, despite GH deficient.

Effects of Additives on the Improvement of Frozen Dough Quality (첨가물이 냉동반죽의 품질향상에 미치는 영향)

  • Lee, Young-Chun;Jeong, Hyung-Won;Yoon, Suk-Kwon
    • Korean Journal of Food Science and Technology
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    • v.36 no.2
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    • pp.217-225
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    • 2004
  • This study was carried out to reduce the loss of frozen dough quality during frozen storage. Using response surface method, ascorbic acid 160.4 ppm, L-cysteine 63.1 ppm, and SSL 0.6% were found to be optimum, with xanthan gum 0.3% (formula A) and Ultra tex-3 5% (formula B) added as cryoprotectants. During frozen storage at $-20^{\circ}C$, control rapidly deteriorated after 4 weeks, while formulas A and B showed slight deterioration with immutable quality after 10 weeks.

Total Spinal Block and Cortical Epidural Block for Whiplash Syndrome and Reflex Sympathetic Dystrophy (Report of Four Cases) (전척수(全脊髓) 및 경막외차단(硬膜外遮斷)으로 편타성(鞭打性) 손상(損傷)의 통증치험(痛症治驗) (4례(例) 보고(報告)))

  • Park, Wook;Ok, See-Young;Song, Hoo-Bin
    • The Korean Journal of Pain
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    • v.1 no.1
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    • pp.106-119
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    • 1988
  • For the relief of pain in 3 cases of whiplash syndromes (case I, II and IV) and in one of reflex sympathetic dystrophy (case III), we have carried out six intentional. total spinal blocks (TSB) which attempted two times in case I, three in case II and one in carte III whoso various symptoms were chronically unresponsive to the usual conservative treatments, and a time of cervical epidural and right suprascapular nerve block in case W whose acute symptom lasted 4 drys following the cervical injury (see fables from 1 to 9). During the 753, we have observed clinically the sequential charges of respiration, lid and pupil reflexes, body motion and consciousness. And checked the blood pressure, pulse rate and arterial Pco2. The effectiveness of those blocks has been assessed by using the Visual Analog Scale which is designed to measure the patient$\acute{s}$ subjective intensity of pain and also we have found out the sequelae following those blocks. The methods of the blocks were as the following: 1. Under the N.P.O. for 8~10 hours, the preparations of immediate cardiopulmonary resuscitation and premedication with atropine 0.5mg at thirty minutes before the TSB, it was performed by injecting the mixture of 2% mepivacaine 10 or 15ml and normal saline 10 or 5ml through No. 23 G. spinal needle into the subarachnoid space of $C_7-T_1$ interspinous region with fully flexed neck on the lateral posture. Immediately after the injection of the local anesthetic in the lateral position, the patient$\acute{s}$ were hasten to change Trendelenburg$\acute{s}$ position in order to act the drugs cephalad and to make easy controlled respiration with oxygen. 2. The cervical epidural block was done by injecting the mixture of 0.5% bupivacaine 4ml, normal saline 4ml and triamcinolone 15mg through No. 18 G. Tuohy needle into the epidural space on the same region and posture as the above without premedication.7he suprascapular nerve block was done by injecting of 0.5% bupivacaine 3ml only into the right suprascapular fossa on the sitting posture. The results were as the following: 1. The cessation of respiration was seen within 5 minutes following the subarachnoidal injection of the above 20ml mixture in 2 to 3 minutes and then soon the consciousness began to disappear. The loss of Lid and pupil reflexes noted between 5 to 10 minutes and the size of the dilated pupils was equal between 5 to 20 minutes, but the pupil of the dependent side on tile lateral position was dilated 1 to 3 minutes earlier than that of the independent. The patients had r=ever responded to any stimulations during the TSB except their heart funtion. 2. The recovery of the TSB was as the following, firstly the ankle and lower limb of the independent side began to move slightly with in 34 to 75 minutes after the injection and then that of the dependent Secondly the neck and upper limb moved 6 to 15 minutes later than the lower limb. Thirdly the self respiration began to appear between 40 to 80 minutes from the block. The lid and pupil reacted to touch and light respectively between 40 to 80 minutes but the pupil of the independent side responded earlier than that of the depends. Lastly the consciousness recovered completely between 80 to 125 minutes from the block. 3. In the cardiopulmonary function during the TSB, the blood pressure were stable except the 210/130 tory at the and block of case I. There were bradycardias between 65 to 85 minutes in case I and II but no arrythmia on the EKG. The level of the arterial Pco2 was maintained to 43~45 torr during the TSB. 4. The effectiveness of the above blocks was no pain(0%) in case IV, and light (10~20%) in case I and II but no improvement in case III. 5. The right arm weakness has been complicated as to be Injected accidently the "COLD" local anesthetic at the End block of case I.

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Study on ${\ulcorner}Bonchojeonghwa{\lrcorner}$ ${\ulcorner}Inbu{\lrcorner}$ ("본초정화(本草精華)" "인부(人部)"에 대한 고찰)

  • Kwon, Young-Bae;Eom, Dong-Myung;Kim, Hong-Kyoon
    • Korean Journal of Oriental Medicine
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    • v.11 no.2
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    • pp.1-22
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    • 2005
  • Study on ${\ulcorner}$Bonchojeonghwa${\lrcorner}$, which is one of the most specialized medical books in Boncho(Herbal Medicines), has been done by comparing it with some other medical books published in the Chosun dynasty. Though there was not meaningful result on e names of Korean medicine by this study and more study should follow in the future, from medicines recorded in ${\ulcorner}$Inbu (a chapter of medical ingredients from human body)${\lrcorner}$, we can reach on some results as follows by comparing in names of Korean medicines, their medical components, relevant explanations and etc. 1. Though it is difficult to know the author and the published year due to absence of the preface and epilogue, the publication is presumed to date from mid-l7th century, from the facts that Muheeong's ${\ulcorner}$Shinnongbonchokyongso${\lrcorner}$ is in the ${\ulcorner}$Bonchojeonghwa${\lrcorner}$'s reference list, and that there is not Hangul expression in the names of medicines nor the Ching dynasty’s books as a reference. 2. As a result of studying on the names of medicines recorded in ${\ulcorner}$Inbu${\lrcorner}$ of the Chosun dynasty's famous medical books, before ${\ulcorner}$ Bonchojeonghwa${\lrcorner}$, 19 medicines in ${\ulcorner}$Hyangyakjipsungbang${\lrcorner}$, 25 in ${\ulcorner}$Donguibogam${\lrcorner}$, and after ${\ulcorner}$Bonchojeonghwa${\lrcorner}$, 6 in ${\ulcorner}$Uimumbogam${\lrcorner}$, 4 in ${\ulcorner}$Kwangjebikup${\lrcorner}$, 11 in ${\ulcorner}$Bangyakhappyon${\lrcorner}$. And there are 37 medicines which are unique, ${\ulcorner}$Bonchojeonghwa${\lrcorner}$ has 31, the biggest records among them. 3. As a result of studying on the names of medicines recorded in 「Inbu」 of the ${\ulcorner}$Bonchojeonghwa${\lrcorner}$ and ${\ulcorner}$ Donguibogam${\lrcorner}$, 22 medicines were recorded in the both books, 9 were only recorded in ${\ulcorner}$Bonchojeonghwa${\lrcorner}$ and 3 were only recorded in ${\ulcorner}$Donguibogam${\lrcorner}$. 3 out of the total 37 medicines recorded in ${\ulcorner}$Inbu${\lrcorner}$ are only recorded in ${\ulcorner}$Hangyakjipsungbang${\lrcorner}$, and more study on this is needed. 4. From the contents recorded in ${\ulcorner}$Bonchojeonghwa${\lrcorner}$ and ${\ulcorner}$Donguibogam${\lrcorner}$, Benchojeonghwa is more in detail than Donguibogam. Thus, it was specialized in Boncho (Herbal Medicines) enough to be compared with general medical books, and played a good role in leading medical science's specialization. 5. Late Chosun dynasty's medical study on Boncho (Herbal Medicines) just like ${\ulcorner}$Bonchojeonghwa${\lrcorner}$ didn't lead to an active development of knowledge communication due to Confucian ethics. This limitation created the trend relying on general medical books or Yaksungga (songs of memorizing Boncho information) for Boncho information, but Boncho information of late Chosun dynasty became more in detail. That is, while Bokhapbang, combination of various medicines, were developed in China, Danmibang, single medicine but different intensity, were developed in Chosun. And thus, even though the kinds of medicines became smaller, but its contents became rather rich. 5. The medicines recorded in ${\ulcorner}$Bonchojeonghwa${\lrcorner}$ and ${\ulcorner}$Donguibogam${\lrcorner}$ are, from the view point of today, unclean or rather uncomfortable to use. Out those medicines, Bunchung, Hwasijangsanginkol, Hongyon, Gonidoogun, Inkondang had been used for a very long time and which proves their medical efficacy, and it is a great pity that they can’t be tried today due to the limitation by modern ethics.

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The Analysis of Forest Vegetation in Mt. Kumjeong (금정산(金井山) 일대(-帶)의 삼림식생분석(森林植生分析))

  • Yun, Chung Weon;Bae, Kwan Ho;Hong, Sung Cheon
    • Current Research on Agriculture and Life Sciences
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    • v.13
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    • pp.31-44
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    • 1995
  • Mt. Kumjeong is located in south-eastern part of the Korean Peninsular($129^{\circ}$01' to $129^{\circ}$05' E, $35^{\circ}$03' to $35^{\circ}$17' N) and the altitude of the summit is 802 meter. In order to find out the vegetation units which made it possible to classify subtropical forest and south-temperate forest, Mt. Kumjeong (which is located in a border of between subtropical forest and south-temperate forest) was selected as a study area. The primary result of actual vegetation analysis in Mt. Kumjeong based upon the vegetation community analysis methods by the ZM-school, and the relationships between vegetation community and two parameters(altitude, topography) analyzed by using coincidence analysis method were summarized as followings. 1. Based upon analytic methods of the vegetation community by the ZM-schools, the primary analytic result of the analysis of vegetation community in Mt. Kumjeong was divided into 10 communities, 9 groups, 2 subgroups. 2. Eurya japonica group of Pinus densiflora community out of 16 vegetation units was thought as a indicator vegetation group which made it possible to border subtropical forest and south-temperate forest. 3. Natural regeneration of Stewartia koreana group was thought to be difficult because seedling and sapling was rarely showed, 4. In relationship between vegetation units and altitude, Carpinus tschonoskii community, Quercus variabilis community, Quercus serrata community, Wisteria floribunda community,. Eurya japonica group of Pinus densiflora community, Pinus thunbergii community mainly distributed below altitude 500 meter, and Quercus mongolica community, Typical group of Pinus densiflora community, Quercus dentata community, Carpinus coreana community, Quercus acutissima community mainly distributed above altitude 500 meter. 5. In relationship between vegetation units and topography, Carpinus tschonoskii community, Quercus variabilis community, Quercus serrata community, Wisteria floribunda community,. Eurya japonica group of Pinus densiflora community distributed below middle slope, Quercus mongolica community, Typical group of Pinus densifiora community, Quercus dentata community, Carpinus coreana community, Pinus thunbergii community Quercus acutissima communily clistributed above midclle slope.

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Numerical modeling of tidal discharge through a permeable dyke from varying surface gradients (내·외 수위차를 이용한 투수성 제체의 조류량 모델링)

  • Hong, Seong Soo;Kim, Tae In;Nguyen, Thao Thi Hoang;Gu, Jeong Bon
    • Proceedings of the Korea Water Resources Association Conference
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    • 2021.06a
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    • pp.219-219
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    • 2021
  • 서해안 중부 아산만 안쪽에 위치하는 평택·당진항에서 장래 개발 예정인 면적 6.9km2의 내항2공구 수역은 내항2공구 외곽호안 - 내항가호안 - 내항2공구 중앙 분리호안으로 둘러싸여 있으며, 투수성 제체인 내항가호안 사석 공극을 통하여 해수가 유통되어 조석 현상이 나타나고 있다. 2020년 8~9월의 2개월간 내항2공구 외곽호안 내·외측에서 조석 관측 결과, 2공구 수역의 최대 조차는 1.97m로서 외측 해역 최대 조차 9.79m의 20.1%이고 내·외측의 순간 수위차는 최대 5.82m에 달한다. 내항가호안은 내항2공구 개발이 거의 완료되는 시기까지 유지될 예정이므로 2공구 개발에 따른 내측 조차와 내·외측 수위차의 변화를 정확하게 예측하는 것은 내항가호안 제체 안전에 매우 중요하다. 이 연구의 목적은 장래 개발단계별 변화 예측에 앞서, 관측이 이루어진 2개월간의 실시간 내측 조석과 내·외측 수위차 시계열을 Delft3D-Flow를 이용하여 기 구축된 아산만 수치모델에서 재현하는 것이다. 내항가호안 제체 통과 유량은 내·외측 수위차에 비례하는 것으로 가정하고, 수위차 - 유량 관계식을 도출하였다. 수위차는 평택 조위관측소와 내항2공구 수역의 1분 간격 관측 조위로부터 산출하였고, 제체 통과 유량은 내측 조위(z, 평택항 DL 기준, m) - 수용적(V, 106m3) 관계식으로 계산하였다. 내측 조위 - 수용적 관계식은 수심측량 성과로부터 V = 0.28z2 + 3.73z + 2.96 (r2=1.00)으로 얻어졌다. 다양한 함수식의 적합성을 검토한 결과, 다음과 같은 수위차(𝚫z, m) - 제체 통과 유량(Q, m3/s) 관계식을 도출하였다. [내항가호안 내측으로 유입시] $Q_{IN}=\{\begin{array}{lll}{\exp}\{0.54\;{\ln}({\Delta}z)+6.00\}&&\text{; }{\Delta}z{\leq}1.8\\219.82{\Delta}z+158.56&&\text{; }{\Delta}z>1.8\end{array}\;\;(r^2=0.86)$ [내항가호안 외측으로 유출시] QOUT = -exp{0.44 ln(-𝚫z) + 5.70} (r2=0.59) 매 𝚫t 마다 제체 통과 유량을 계산하는 알고리즘을 Delft3D 소스 코드에 추가하고, 8개 분조 합성조석(M2, S2, K1, O1, N2, K2, P1, Q1)을 외력조건으로 설정하여 2개월간 조석 수치모델링을 수행하였다. 내항2공구 수역의 매 시별 조위 관측치와 모델치를 비교한 결과, 오차는 -0.37~0.37m의 범위이고, 오차 평균은 0.02m, 절대오차 평균은 0.08m로 상당히 정확하게 실시간 조위 변동을 모의하였다. 보정·검정된 이 모델을 이용하여 향후 내항2공구 개발에 따른 내측 조석과 내·외측 수위차 변화에 대한 예측모의를 진행할 예정이다.

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