• Title/Summary/Keyword: Self-potential

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Highly Doped Nano-crystal Embedded Polymorphous Silicon Thin Film Deposited by Using Neutral Beam Assisted CVD at Room Temperature

  • Jang, Jin-Nyeong;Lee, Dong-Hyeok;So, Hyeon-Uk;Hong, Mun-Pyo
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.08a
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    • pp.154-155
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    • 2012
  • The promise of nano-crystalites (nc) as a technological material, for applications including display backplane, and solar cells, may ultimately depend on tailoring their behavior through doping and crystallinity. Impurities can strongly modify electronic and optical properties of bulk and nc semiconductors. Highly doped dopant also effect structural properties (both grain size, crystal fraction) of nc-Si thin film. As discussed in several literatures, P atoms or radicals have the tendency to reside on the surface of nc. The P-radical segregation on the nano-grain surfaces that called self-purification may reduce the possibility of new nucleation because of the five-coordination of P. In addition, the P doping levels of ${\sim}2{\times}10^{21}\;at/cm^3$ is the solubility limitation of P in Si; the solubility of nc thin film should be smaller. Therefore, the non-activated P tends to segregate on the grain boundaries and the surface of nc. These mechanisms could prevent new nucleation on the existing grain surface. Therefore, most researches shown that highly doped nc-thin film by using conventional PECVD deposition system tended to have low crystallinity, where the formation energy of nucleation should be higher than the nc surface in the intrinsic materials. If the deposition technology that can make highly doped and simultaneously highly crystallized nc at low temperature, it can lead processes of next generation flexible devices. Recently, we are developing a novel CVD technology with a neutral particle beam (NPB) source, named as neutral beam assisted CVD (NBaCVD), which controls the energy of incident neutral particles in the range of 1~300eV in order to enhance the atomic activation and crystalline of thin films at low temperatures. During the formation of the nc-/pm-Si thin films by the NBaCVD with various process conditions, NPB energy directly controlled by the reflector bias and effectively increased crystal fraction (~80%) by uniformly distributed nc grains with 3~10 nm size. In the case of phosphorous doped Si thin films, the doping efficiency also increased as increasing the reflector bias (i.e. increasing NPB energy). At 330V of reflector bias, activation energy of the doped nc-Si thin film reduced as low as 0.001 eV. This means dopants are fully occupied as substitutional site, even though the Si thin film has nano-sized grain structure. And activated dopant concentration is recorded as high as up to 1020 #/$cm^3$ at very low process temperature (< $80^{\circ}C$) process without any post annealing. Theoretical solubility for the higher dopant concentration in Si thin film for order of 1020 #/$cm^3$ can be done only high temperature process or post annealing over $650^{\circ}C$. In general, as decreasing the grain size, the dopant binding energy increases as ratio of 1 of diameter of grain and the dopant hardly be activated. The highly doped nc-Si thin film by low-temperature NBaCVD process had smaller average grain size under 10 nm (measured by GIWAXS, GISAXS and TEM analysis), but achieved very higher activation of phosphorous dopant; NB energy sufficiently transports its energy to doping and crystallization even though without supplying additional thermal energy. TEM image shows that incubation layer does not formed between nc-Si film and SiO2 under later and highly crystallized nc-Si film is constructed with uniformly distributed nano-grains in polymorphous tissues. The nucleation should be start at the first layer on the SiO2 later, but it hardly growth to be cone-shaped micro-size grains. The nc-grain evenly embedded pm-Si thin film can be formatted by competition of the nucleation and the crystal growing, which depend on the NPB energies. In the evaluation of the light soaking degradation of photoconductivity, while conventional intrinsic and n-type doped a-Si thin films appeared typical degradation of photoconductivity, all of the nc-Si thin films processed by the NBaCVD show only a few % of degradation of it. From FTIR and RAMAN spectra, the energetic hydrogen NB atoms passivate nano-grain boundaries during the NBaCVD process because of the high diffusivity and chemical potential of hydrogen atoms.

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A study on consumers' consumption culture of Panax ginseng -Focused on college students' attitude and purchase intent for ginseng, and related products - (소비자의 인삼 소비문화 -대학생 소비자의 인삼에 대한 태도 및 구매의도를 중심으로-)

  • Kim, Siwuel
    • Journal of Ginseng Culture
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    • v.2
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    • pp.71-83
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    • 2020
  • College students are the potential income classes preparing for income activities and are the main consumers of the future that are very important. In order to understand the current state of ginseng-related consumption culture of young consumers, this study wanted to examine university students' attitudes toward ginseng-related products and services in the future, and to find out their purchasing status, satisfaction, and intent to purchase them. In doing so, we looked at the relative influence of the relevant variables that affect the intent of the purchase. As a result, the variables that affect college student consumers' intention to purchase ginseng-related products were shown in the order of their reliability, economy, purchasing experience, subjective interest, monthly income, monthly allowance, pride in ginseng, and age. Of these, most of the variables had positive effects, but the average monthly income, monthly allowance, and age had negative effects. In other words, the higher the reliability, economy, and self-esteem of ginseng, the higher the willingness to buy ginseng, the higher the subjective interest in ginseng, the higher the age, the lower the monthly allowance, and the lower the income, the lower the willingness to buy ginseng. To promote college students' consumption of ginseng products, it is necessary to cut prices for the younger generation, enhance the quality of the products for the younger generation, improve the taste to overcome the negative aspects of rejecting the bitter and bitter taste, and, above all, induce consumers' attention. It is also necessary to expand accessibility through the development of convenient and easy-to-eat products for young people and the expansion of sales outlets. Recently, young consumers are interested in new products they have never experienced before, products that are good to certify because of their unique design or packaging, and retro products that stimulate nostalgia in the past, so they need to promote and provide information related to consumption of ginseng products in this regard. Considering the practicality and convenience of consumers, we propose consideration of personal consumers' taste curation services, which reflect their preference for products that are convenient to carry with them in line with various living environments, and can have synergy with other products.

Efficient Culture Method for Early Passage hESCs after Thawing (초기 계대 인간 배아줄기세포의 해동 후 효율적인 배양 방법)

  • Baek, Jin-Ah;Kim, Hee-Sun;Seol, Hye-Won;Seo, Jin;Jung, Ju-Won;Yoon, Bo-Ae;Park, Yong-Bin;Oh, Sun-Kyung;Ku, Seung-Yup;Kim, Seok-Hyun;Choi, Young-Min;Moon, Shin-Yong
    • Clinical and Experimental Reproductive Medicine
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    • v.36 no.4
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    • pp.311-319
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    • 2009
  • Objective: Human embryonic stem cells (hESCs) have the capacity to differentiate into all of the cell types and therefore hold promise for cell therapeutic applications. In order to utilize this important potential of hESCs, enhancement of currently used technologies for handling and manipulating the cells is required. The cryopreservation of hESC colonies was successfully performed using the vitrification and slow freezing-rapid thawing method. However, most of the hESC colonies were showed extremely spontaneous differentiation after freezing and thawing. In this study, we were performed to rapidly collect of early passage hESCs, which was thawed and had high rate of spontaneously differentiation of SNUhES11 cell line. Methods: Four days after plating, partially spontaneously differentiated parts of hESC colony were cut off using finely drawn-out dissecting pipette, which is mechanical separation method. Results: After separating of spontaneously differentiated cells, we observed that removed parts were recovered by undifferentiated cells. Furthermore, mechanical separation method was more efficient for hESCs expansion after thawing when we repeated this method. The recovery rate after removing differentiated parts of hESC colonies were 55.0%, 74.5%, and 71.1% when we have applied this method to three passages. Conclusion: Mechanical separation method is highly effective for rapidly collecting and large volumes of undifferentiated cells after thawing of cryopreserved early passage hESCs.

Growth of Soybean Sprouts and Concentration of $CO_2$ Produced in Culture Vessel Affected by Watering Methods (살수방식에 따른 재배용기내 Gas 조성 및 콩나물의 생육 변화)

  • 배경근;남승우;김경남;황영현
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.49 no.3
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    • pp.167-171
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    • 2004
  • The growth of soybean sprout was greatly influenced by watering systems: Fixed watering system (water tub was loaded at ceiling upper of culture box and water was showered by bottom holes) was estimated the better than that of reciprocating watering and tub immersing watering because it could cool down the temperature in culture box and wash the organic substances on the body of sprout. The fixed watering system showed good body color and preventing effect of partial rotting of sprout because it could discharge $\textrm{CO}_2$ gas effectively in culture box and keep the concentration below 5%. The concentration of gases at the bottom (about 30 cm height from basal plate) of culture box in fourth or fifth days was L6% for $\textrm{CO}_2$ and 13-16% for $\textrm{O}_2$, respectively. The optimum gas concentration in culture box was considered to be over 10% for $\textrm{O}_2$ and below 5% for $\textrm{CO}_2$.

Development of Needs Extraction Algorithm Fitting for Individuals in Care Management for the Elderly in Home (재가노인 사례관리의 욕구사정 정확도 향상을 위한 욕구추출 알고리즘 개발 - 데이터 마이닝 분석기법을 활용하여 -)

  • Kim, Young-Sook;Jung, Kook-In;Park, So-Rah
    • Korean Journal of Social Welfare
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    • v.60 no.1
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    • pp.187-209
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    • 2008
  • The authors developed 28 needs assessment tools for integrated assessment centered on needs, which is the core element in care management for the elderly in home. Also, the authors collected the assessment data of 676 elderly persons in home from 120 centers under the Korea Association of Senior Welfare Centers by using the needs assessment tools, and finally developed needs extraction algorithm through decision tree analysis in data mining to identify their actual needs and provide social welfare service suitable for such needs. The needs extraction algorithm for 28 needs of the elderly in home are summarized in

    . The Need No. 8 "Having need of help in going out" of the decision-making model, for example, was divided into 80.3% of asking for help and 11.4% not asking for help with Appeal No. 23 as a major variable. The need increased by 87.9% when the elderly appealed for help to go out and they had a caregiver but decreased by 47.4% when they had no caregiver. When the elderly asked for help in going out, they had a caregiver, and they needed complete help in cleaning, their need of help in going out was shown as 94.2%. However, seen from their answer that they needed complete help in bathing of ADL even if they did not ask for help in going out, it was found that the need of help in going out sharply increased from 11.4% to 80.0%. On the other hand, when they needed partial help or self-supported in bathing, the potential for them to be classified as asking for help in going out was shown to be low as 7.7%. In the said decision-making model, the number of cases for parent node and child node was designated as 50 and 25, respectively, with level 5 of the maximum tree depth as stopping rule. By this, it was shown that their decision-making was found to be effective as 182.13% for the need "Having need of help in going out". The algorithm presented in this study can be useful as systematic and scientific fundamental data in assessment of needs of the elderly in home.

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  • Brain Regions Associated With Anhedonia in Healthy Adults : a PET Correlation Study (정상 성인에서 양전자방출단층촬영을 통해 관찰한 무쾌감증 관련 뇌 영역)

    • Jung, Young-Chul;Seok, Jeong-Ho;Chun, Ji-Won;Park, Hae-Jeong;Lee, Jong-Doo;Kim, Jae-Jin
      • The Korean Journal of Nuclear Medicine
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      • v.39 no.6
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      • pp.438-444
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      • 2005
    • Purpose: Anhedonia has been proposed to be the result of a basic neurophysiologic dysfunction and a vulnerability marker that precede and contribute to the liability of developing schizophrenia. We hypothesized that anhedonia, as a construct reflecting the decreased capacity to experience pleasure, should be associated with decreased positive hedonic affect trait. This study examined the relationship between anhedonia and positive hedonic affect trait and searched for the brain legions which correlate with anhedonia in normal subjects. Materials and Methods: Using $^{18}F$-FDG PET scan, we investigated the brain activity of twenty one subjects during resting state. Questionnaires were administrated after the scan in order to assess the self-rated individual differences in physical/social anhedonia and positive/negative affect traits. Results: Negative correlation between physical anhedonia score and positive affect trait score was significant (Pearson coefficient =-0.440, p<0.05). The subjects physical and social anhedonia scores showed positive correlation with metabolic rates in the cerebellum and negative correlation with metabolic rates in the inferior temporal gyrus and middie frontal gyrus. In addition, the positive affect trait score positively correlated with various areas, most prominent with the inferior temporal gyrus. Conclusion: These results suggest that neural substrates, such as the inferior temporal gyrus and prefrontal-cerebellar circuit, which dysfunction has been proposed to be involved with the cognitive deficits of schizophrenia, may also play a significant role in the liability of affective deficits like anhedonia.

    Retention Characteristics of Tc-99m-Pullulan-Derivatives in CT26 Tumor of Mice (마우스 CT26 종양에서 Tc-99m 표지 플루란유도체의 저류 특성)

    • Heo, Young-Jun;Song, Ho-Chun;Bom, Hee-Seung;Na, Kun;Kim, Seong-Min
      • The Korean Journal of Nuclear Medicine
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      • v.37 no.6
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      • pp.393-401
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      • 2003
    • Objective: Pullulan derivatives (PD) can be used to make self-assembled hydrogel nanoparticles which are responsive to ionic strength. The aim of this study is to evaluate the potential of PD as a retaining carrier of radioisotope inside tumors. Materials and Methods: Four types of PD were evaluated which included pullulan acetate (PA), succinylated PA (SPA), PA-DTPA and SPA-DTPA conjugates. They were radiolabeled with Tc-99m. Labelling efficiencies were determined at 30 min, 1, 2, 4 and 12 hours after radiolabeling. CT-25 colon cancer cells were subcutaneously injected into Balb/c mice. After 2 weeks of subcutaneous injection, Tc-99m-labelled PD (Tc-99m-PD) were injected into the tumors. Whole body images of mice were obtained at 30 min, 1, 2, and 12 hr after intratumoral injection. All twenty mice were grouped into four groups by largest diameter; control A (largest diameter = 5 mm, n = 5), control B (largest diameter = 10 mm, n = 5), pullulan A (largest diameter = 5 mm, n = 5), pllulan B (largest diameter = 10 mm, n = 5). Dynamic images were obtained for 1 hour after intratumoral injection. Static images were obtained at 1 hr, 2 hr, 3 hr and 4 hr after intratumoral injection with Tc-99m pertechnetate and Tc-99m-PA. Target-to-background ratios and retention rates were calculated. Results: Labeling efficiencies of PA, SPA, PA-DTPA and SPA-DTPA were $94.5{\pm}5.9%,\;97.8{\pm}3.5%\;94.2{\pm}3.8%,\;and\;92.5{\pm}6.2%$, respectively (p>0.05). Percent retention rates (%RR) of PA and PA-DTPA were significantly higher than those of control, however, those of SP-DTPA and SPA became similar to control at 4 and 12 hr, respectively. %RR of pullulan A and pullulan B at 1, 4 and 8 hr is significantly higher than that of control (p < 0.05). However, %RR between pullulan A and pullulan B were similar. Conclusion: The lonic strength dependent PD-nanoparticles are retained in the tumor. No difference of %RR according to tumor size was noted. Therapeutic application of PD labelled with beta- or alpha- emitting radionuclides can be expected.

    A Study on the Change of AIDS Knowledge and Sexual Behavior among Middle and High School Students through AIDS Prevention Education (중고등학생의 에이즈 예방교육(豫防敎育)을 통한 에이즈 지식(知識)과 성의식(性意識) 변화(變化)에 관(關)한 연구(硏究))

    • Kwon, Kwan-Woo;Lee, Kyoung-Mu;Kim, Joung-Soon
      • Journal of the Korean Society of School Health
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      • v.12 no.1
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      • pp.109-129
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      • 1999
    • AIDS is worldwide problem. It has threatens societies and is potentially a big problem among youth. UNAIDS has warned that collective global responses are necessary; with half of the newly infected being children and young people in 1998, educating youth below age 24 is essential. Because of both their unexpected, strong sexual activities and an easjer tendency to change their behavior than adults, UNAIDS emphasizes the importance of prevention education for youth. In Korea, 4 cases of HIV infection have officially been reported among high school students. Considering the potential seriousness of HIV infection among youth, the Korean AntiAIDS Federation (KAAF) began an education programme for Korean youth (middle & high school pupils) as one intervention method in 1993. The purpose of this study is to evaluate the impact of the education programs performed and to develop a better programme. The intervention method used in this study was mainly a lecture in a big or small auditorium or through broadcasting systems using audio-visual teaching aids. The period of this survey was from Nov. 10 to Dec. 26. in 1998. The subjects surveyed were 792 pupils who were sampled from 12 different middle and high schools in Seoul by a two-stage cluster sampling. Self-recording the structured questionnaire was used for data collection. Data were analyzed by using a paired t-test to compare the knowledge difference before and after the interrention method. A chi-square test to compare the consciousness difference between pre-post-education results was used, and an ANOVA was ased to compare the knowledge difference among the selected groups. Major results of this study are summarized as follows: (1) AIDS knowledge significantly changed after AIDS prevention education. (2) The direct lecture in a big or small auditorium is more effective than an indirect lecture through a broadcasting system or through audio-visual teaching aids. (3) Those who had not seen obscene materials (e.g. pornography films, magazines etc.) acguired much more knowledge than others after AIDS prevention education. (4) Those who had no girlfriend/or boyfriend acquired much more knowledge than the others after AIDS prevention education. (5) As to the attitudes toward chastity, more girls than boys and students who had not seen obscene materials rather than those who already had were liable to support the state ment: "all should remain chase" and their consciousness on "being chaste" changed much more than that of others after intervention. (6) As to the individual evaluation of lectures, 23.1% shows "very good", 44.1% "good", 26.9% "normar" '-' thus, the positive evaluation was to 94.2%. The negative response was 5.8%. (7) As to the desire for AIDS education sponsored by KAAF in the future, more than 90.5% showed a positive reaction. (8) As to the educators in future education methods, pupils wanted lecturers from outside their schood. (9) Students from vocational high schools have seen obscene materials much more than other groups and the percentage of those who had a girlfriend/or boyfriend was higher than that of the others as wello. (10) 90% of those who watched obscene materials responded that they experienced these materials while at middle school and 100% before reaching the second grade of high school. (11) The number of boys who have experienced obscene materials is twice as many as that of girls. (12) The percentage of boys who have a girlfriend is much higher than the percentage of girls who have a boyfriend. (13) Among those who have friends of the opposite sex, 11.1% say that they hare had sexual contact and 20.8% hare experienced kissing and caressing.

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    The Construction Direction of the ROK NAVY for the Protection of Marine Sovereignty (국가의 해양주권 수호를 위한 한국해군의 전력건설 방향)

    • Shin, In-Kyun
      • Strategy21
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      • s.30
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      • pp.99-142
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      • 2012
    • Withe increased North Korea's security threats, the South Korean navy has been faced with deteriorating security environment. While North Korea has increased asymmetric forces in the maritime and underwater with the development of nuclear weapons, and China and Japan have made a large investment in the buildup of naval forces, the power of the Pacific fleet of the US, a key ally is expected to be weakened. The biggest threat comes from China's intervention in case of full-scale war with North Korea, but low-density conflict issues are also serious problems. North Korea has violated the Armistice Agreement 2,660 times since the end of Korean War, among which the number of marine provocations reaches 1,430 times, and the tension over the NLL issue has been intensifying. With tension mounting between Korea and Japan over the Dokdo issue and conflict escalating with China over Ieo do Islet, the US Navy has confronted situation where it cannot fully concentrate on the security of the Korean peninsula, which leads to need for strengthening of South Korea's naval forces. Let's look at naval forces of neighboring countries. North Korea is threatening South Korean navy with its increased asymmetric forces, including submarines. China has achieved the remarkable development of naval forces since the promotion of 3-step plan to strengthen naval power from 1989, and it now retains highly modernized naval forces. Japan makes an investment in the construction of stat of the art warship every year. Since Japan's warship boasts of its advanced performance, Japan's Maritime Self Defense Force is evaluated the second most powerful behind the US Navy on the assumption that submarine power is not included in the naval forces. In this situation, naval power construction of South Korean navy should be done in phases, focusing on the followings; First, military strength to repel the energy warship quickly without any damage in case of battle with North Korea needs to be secured. Second, it is necessary to develop abilities to discourage the use of nuclear weapons of North Korea and attack its nuclear facilities in case of emergency. Third, construction of military power to suppress armed provocations from China and Japan is required. Based on the above naval power construction methods, the direction of power construction is suggested as follows. The sea fleet needs to build up its war potential to defeat the naval forces of North Korea quickly and participate in anti-submarine operations in response to North Korea's provocations. The task fleet should be composed of 3 task flotilla and retain the power to support the sea fleet and suppress the occurrence of maritime disputes with neighboring countries. In addition, it is necessary to expand submarine power, a high value power asset in preparation for establishment of submarine headquarters in 2015, develop anti-submarine helicopter and load SLAM-ER missile onto P-3C patrol aircraft. In case of maine corps, division class military force should be able to conduct landing operations. It takes more than 10 years to construct a new warship. Accordingly, it is necessary to establish plans for naval power construction carefully in consideration of reality and future. For the naval forces to safeguard maritime sovereignty and contribute to national security, the acquisition of a huge budget and buildup of military power is required. In this regard, enhancement of naval power can be achieved only through national, political and military understanding and agreement. It is necessary to let the nation know that modern naval forces with improved weapon system can serve as comprehensive armed forces to secure the command of the sea, perform defense of territory and territorial sky and attack the enemy's strategic facilities and budget inputted in the naval forces is the essential source for early end of the war and minimization of damage to the people. If the naval power construction is not realized, we can be faced with a national disgrace of usurpation of national sovereignty of 100 years ago. Accordingly, the strengthening of naval forces must be realized.

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    Denitrification and COD, TN and SS fluxes in Komso Bay, Korea (곰소만에서의 오염물질 플럭스 및 탈질산화)

    • Kim Do-Hee;Yang Jae-Sam
      • Journal of the Korean Society for Marine Environment & Energy
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      • v.4 no.4
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      • pp.32-41
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      • 2001
    • We measured the fluxes of COD, TN and 55 in addition to composition and quality of sediment in Komso Bay, West Coast of Korea. The fluxes of TN, SS and COD were measured during flood tide and ebb tide in April and August, 2000. Denitrification rates in the sediments was also measured by direct produced $N_2$ gas technique on April and August from 1999 to 2000 in the same sea area. The composition of the sediments were 0.33~5.67 % of sand, 20.2~25.6 of gravel and 68.7~77.0 % of silt. Ignition loss of the sediments were 6.58~7.50 %. The concentration of hydrogen sulfide in the sediments were 0.028~0.326 mg/gㆍdry and oxidation reduction potential of the sediments were -28~-15 mV Diurnal fluxes of COD, total nitrogen, and suspended solids with tidal current and denitrification rate in the tidal flat have been determined in Komso Bay The diurnal net flux of COD was same in April. While 14.4 ton COD/hr of net influx into the tidal flat was recorded in August. The diurnal net influx of total nitrogen was 0.16 ton N/hr in April and 1.13 ton N/hr in August. The diurnal net influx of suspended solids was 0.05 ton SS/hr in April, and also net influx of suspended solids was 0.29 ton SS/hr in August. The overall purification ability of the tidal flat were estimated 0.00~5.69 g COD/$m^2/day$, 0.06~0.45 g N/m²/day and 0.02~0.12 g SS/$m^2/day$ for COD, TN and SS, respectively. Denitrification rate was 0.009~1.720 m mole ${N_2}/m^2/day$ (average 0.702 m mole ${N_2}/m^2/day$) in April and 0.033~0.133 m mole ${N_2}/m^2/day$ (average 0.077 m mole ${N_2}/m^2/day$) in August, 1999. 0.000~l.909 m mole ${N_2}/m^2/day$ (average 0.756 m mole ${N_2}/m^2/day$) in April, 0.000~1.691 m mole ${N_2}/m^2/day$ (average 0.392 m mole ${N_2}/m^2/day$) in August, 2000. Even with a wide range of denitrification rate depending on the sampling location and studied periods, the average denitrification rate was estimated 0.482 m mole ${N_2}/m^2/day$ in the tidal flat of Komso Bay.

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