• Title/Summary/Keyword: self-stability

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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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Conceptions Toward Career Development and Occupational View between Giftedness in Computer Science and Normal Students in Elementary School (초등정보과학영재와 일반학생의 진로발달 및 직업관 인식에 대한 조사 연구)

  • Lee, Jaeho;Choi, Seung Hee
    • Journal of Gifted/Talented Education
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    • v.24 no.4
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    • pp.613-628
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    • 2014
  • The purpose of this study is to compare the differences of the career development and the occupational view between giftedness in computer science and normal students in elementary school, so the results of this study provide assistance to the teacher for the direction and guidance on the career education of the giftedness in computer science in elementary school. This survey is based on 82 giftedness in computer science and 167 normal elementary school students. The questionnaires used in the study contain questions asking regarding the career development and the occupational view. The results of this study were as follows : First, according to the consciousness analysis result about career, the giftedness in computer science choose to be scientific technicians, the normal students choose to be artists. The both groups get career information from their parents, but they usually don't get career counseling from teachers. The education of giftedness in computer science does not contribute to changing their dreams, while normal students have no interest in computer science. Second, according to the career development analysis result, in comparison with non-gifted students, the gifted in information science had more success in all domains of career development. Third, according to the occupational view analysis result, the information science gifted students had higher meaningful rate than the normal students. Intrinsic domain' had higher meaningful rate among the subordinate domains, there is no difference in 'extrinsic domain' and 'incidental domain' between the information science gifted students and the normal students. Fourth, according to the correlation analysis result of the career development and the occupational view, there is a positive correlation in all domains of them. The high they are in the career development, the more they have the certain occupational view. Likewise, if they have the certain occupational view, they will be more successful in career development. Based on the findings of this research, the directing and guidance on the career education of giftedness in computer science in elementary school is same as the followings. We should educate parents regarding information about career for students who are under the influence of parents greatly and indicate them to apply to their children appropriately. In addition, for making them to have the positive image of the computer science, teacher should provide more information about the area of information and form various curriculums to induce more interests about computer science. We need to strengthen the career education for guiding the gifted to assist them to establish their own goal and realize them how to study and choose their career in the future. In school education field, it must develop and manage the definite and empirical program, not the career development program which is focused on only entrance into advanced school, to boost self-realization ability and the suitable career education program based on the correct understanding on giftedness in computer science. For this, through steady trying and research, teachers should be eater to develop the career education for students. Also, we have to implement the internal stability career education program, so it will help students to be aware of their job and career; therefore, students will be able to plan and prepare for their career in this rapid changing world.

Analysis of Safety Education Contents of 『Field of home life』 in Technology·Home Economics Textbook developed by the revised curriculum in 2009 (2009 개정 기술·가정 교과서 『가정생활영역』의 안전교육 내용 분석)

  • Kim, Nam Eun
    • Journal of Korean Home Economics Education Association
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    • v.29 no.2
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    • pp.23-39
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    • 2017
  • The Purpose of this study is to present the basic data for selecting and improving the safety education contents which help practically middle school students through analysis of contents of safety education in 'field of home life' of 2009 revised middle school textbooks. The subjects of analysis are 12 types of middle school textbooks: in total 24 books written by 12 publishers in terms of the revised curriculum in 2009. The analysis criteria is developed by the researcher referring to preceding studies regarding safety education based on the seventh safety education standard presented by the Ministry of Education (2015). With such analysis criteria, all words related to the contents of the safety education of analysis criteria were extracted from each textbook, such as words directly mentioned as 'safety', words mean as 'psychological safety' and 'happy life', words related to 'attention', 'note', 'stability' etc. Under the analytic frame of safety education contents according to a home economics textbook, content analysis method was used for producing the frequency and percent of those words. The textbook analysis shows that the number of pages regarding safety education is 336.3 pages, as 9.8% in total 3,412 pages of 12 types of technology and home economics textbooks. As following the analysis of each textbook volume of the proportion in the contents related to safety education, 224.9 pages are on the first volume and 111.9 pages are on the second volume. As grades increase from year one to year three, the proportion of safety education in home economics textbooks is decreased. The highest number of safety education contents unit is 'Self-management of youth' which includes three parts of safety education. In the case of a unit for emphasizing practice, experience and practical exercise such as 'Life of youth' and 'Practice of eco-living', safety education content in the area of 'life safety' are mostly contained. Safety accidents related to the most student experienced, Household accidents (1.4%) and experiment or practice accidents (0.3%) are presented in a low figure. The contents of universal housing and school violence are duplicated on first and second volume of text. The most presented safety education content in the 12 types of textbooks are proper sexual attitude, dietary problems, family conflict and food choice. The least common contents are dangerous drugs, family welfare, internet addiction and industrial accident compensation insurance. As this study is to analyze 12 textbooks developed in 2009 revision curriculum, it is necessary to compare it with the textbook written by the revised curriculum in 2015 and to clarify the contents system of safety education and to avoid duplication of contents. In addition, it is necessary to develop and distribute a safety education program that can support textbooks.

Study on the relationship between family dining and personality in adolescence (중·고등학생의 가족식사와 인성특성에 관한 연구)

  • Shin, Hyoshick;Yu, Nan Sook;Jung, Lanhee;Heo, Youngsun;Lee, Joohee
    • Journal of Korean Home Economics Education Association
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    • v.29 no.4
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    • pp.1-14
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    • 2017
  • This study described the status of family dining and personality of adolescents, determined the differences in family dining according to personal variables, and examined the relationship between family dining and personality in adolescence. The Data were collected from self-reported inventory of the middle and high school students in a city and 1,259 data copies were used for analyses. Data were analyzed for frequency, percentage, mean, standard deviation, Cronbach's ${\alpha}$, t-test, ANOVA, scheffe test, and multiple regression analysis using SPSS/PC 18.0 program. The results obtained were as follows. First, as for the weekly family dining frequency, more than 7 times had the most number of responses(44.2%), followed by 1~2 times(20.8%), 3~4 times(18.1%), 5~6 times(12.9%). The average scores for family dining perception and family dining attitudes were 3.75 and 3.42 on a 5-Likert scale, respectively, which means moderately high. But, family dining rules was 2.80, which means moderate. Agreeableness was the highest(3.68) among the personality components followed by Openness/intellect(3.42), Extraversion(3.33), Conscientiousness(3.14), and Emotional Stability(3.05) out of 5-point Likert scale. Second, there were statistically significant differences in family dining frequency, family dining perception, family dining rules, and family dining attitudes depending on the gender, school level, and the father's academic attainment. Third, family dining frequency, family dining perception, and family dining attitudes had statistically significant influence on the personality of adolescents after personal variables were considered. But, there was no significant relationship between family dining rules and the personality. The outcomes indicate that family dining affects the personality of adolescents. School needs to offer quality programs with various teaching methods to enhance family dining frequency, family dining perception, and family dining attitudes.

Morphological and Nutritional Characteristics and Crossability with Brassica Species of Baemoochae, xBrassicoraphanus (배무채의 형태와 영양적 특성 및 교잡 친화성)

  • Lee, Soo-Seong;Kim, Tae Yoon;Yang, Jungmin;Kim, Jongkee;Lim, Sooyeon;Yoon, Moo Kyoung
    • Horticultural Science & Technology
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    • v.30 no.5
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    • pp.543-548
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    • 2012
  • Morphological characters of Baemoochae, xBrassicoraphanus are mostly intermedium of the both parents, Chinese cabbage, Brassica rapa ssp. pekinensis and radish, Raphanus sativus. The upper and lower parts of the leaf resemble the shape of Chinese cabbage and radish, respectively. The midrib of the leaf is round like to that of radish, but very big more than 3 cm in diameter and white in color like that of Chinese cabbage. The root was changed from the swollen type like that of radish to the enlarged taproot like that of the land race of Chinese cabbage after attaining genetical stability. The flower is white. The seed pod is divided into 2 different parts; the upper part is radish and about 4 cm in length and holds 3-4 seeds and the lower part is Chinese cabbage and about 3 cm in length and holds 7-8 seeds. The color of seed is brown, weight per 1.000 seeds is 5.5 g and the number of seeds per mL is 120. The matured plant in the fall season is around 5 kg in weight and outer leaves are very vigorous and stiffly and inner leaves are erect and form a loose head. The leaf and the root contain a high level of sulforaphene which is well known as a functional substance for anti-cancer and anti-super-bacteria. Baemoochae is an amphidiploid and does not have the self incompatibility function. It has a high level of cross compatibility with Chinese cabbage as the female parent, but not the male parent. It is cross incompatible to cabbage, B. oleracea, black mustard, B. nigra and radish. However it is highly compatible to oil seed rape, B. napus, yellow mustard, B. carinata and partial compatible to muatard, B. juncea in the reciprocal cross.

International Monetary System Reform and the G20 (국제통화제도의 개혁과 G20)

  • Cho, Yoon Je
    • KDI Journal of Economic Policy
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    • v.32 no.4
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    • pp.153-195
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    • 2010
  • The recent global financial crisis has been the outcome of, among other things, the mismatch between institutions and the reality of the market in the current global financial system. The International financial institutions (IFIs) that were designed more than 60 years ago can no longer effectively meet the challenges posed by the current global economy. While the global financial market has become integrated like a single market, there is no international lender of last resort or global regulatory body. There also has been a rapid shift in the weight of economic power. The share of the Group of 7 (G7) countries in global gross domestic product (GDP) fell and the share of emerging market economies increased rapidly. Therefore, the tasks facing us today are: (i) to reform the IFIs -mandate, resources, management, and governance structure; (ii) to reform the system such as the international monetary system (IMS), and regulatory framework of the global financial system; and (iii) to reform global economic governance. The main focus of this paper will be the IMS reform and the role of the Group of Twenty (G20) summit meetings. The current IMS problems can be summarized as follows. First, the demand for foreign reserve accumulation has been increasing despite the movement from fixed exchange rate regimes to floating rate regimes some 40 years ago. Second, this increasing demand for foreign reserves has been concentrated in US dollar assets, especially public securities. Third, as the IMS relies too heavily on the supply of currency issued by a center country (the US), it gives an exorbitant privilege to this country, which can issue Treasury bills at the lowest possible interest rate in the international capital market. Fourth, as a related problem, the global financial system depends too heavily on the center country's ability to maintain the stability of the value of its currency and strength of its own financial system. Fifth, international capital flows have been distorted in the current IMS, from EMEs and developing countries where the productivity of capital investment is higher, to advanced economies, especially the US, where the return to capital investment is lower. Given these problems, there have been various proposals to reform the current IMS. They can be grouped into two: demand-side and supply-side reform. The key in the former is how to reduce the widespread strong demand for foreign reserve holdings among EMEs. There have been several proposals to reduce the self-insurance motivation. They include third-party insurance and the expansion of the opportunity to borrow from a global and regional reserve pool, or access to global lender of last resort (or something similar). However, the first option would be too costly. That leads us to the second option - building a stronger globalfinancial safety net. Discussions on supply-side reform of the IMS focus on how to diversify the supply of international reserve currency. The proposals include moving to a multiple currency system; increased allocation and wider use of special drawing rights (SDR); and creating a new global reserve currency. A key question is whether diversification should be encouraged among suitable existing currencies, or if it should be sought more with global reserve assets, acting as a complement or even substitute to existing ones. Each proposal has its pros and cons; they also face trade-offs between desirability and political feasibility. The transition would require close collaboration among the major players. This should include efforts at the least to strengthen policy coordination and collaboration among the major economies, and to reform the IMF to make it a more effective institution for bilateral and multilateral surveillance and as an international lender of last resort. The success on both fronts depends heavily on global economic governance reform and the role of the G20. The challenge is how to make the G20 effective. Without institutional innovations within the G20, there is a high risk that its summits will follow the path of previous summit meetings, such as G7/G8.

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Regulation of Professional Advertising: Focusing on Physician Advertising (전문직 표시·광고규제의 몇 가지 쟁점: 의료광고를 중심으로)

  • Lee, Dongjin
    • The Korean Society of Law and Medicine
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    • v.17 no.2
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    • pp.177-219
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    • 2016
  • A commercial advertisement is not only a way of competition but also a medium of communication. Thus, it is under the constitutional protection of the freedom of business (article 15 of the Constitution) as well as the freedom of press [article 21 (1) of the Constitution]. In terms of the freedom of business or competition, it should be noted that an unfair advertising (false or misleading advertisement) can be regulated as an unfair competition, while any restraint on advertising other than unfair one might be doubted as an unjustifiable restraint of trade. In terms of the freedom of press or communication, it is important that article 21 (2) of the Constitution forbids any kind of (prior) censorship, and the Constitutional Court applies this restriction even to commercial advertising. In this article, the applicability of these schemes to advertising of the so-called learned professions, especially physician, are to be examined, and some proposals for the reformation of the current regulatory regime are to be made. Main arguments of this article can be summarized as follows: First, the current regime which requires advance review of physician advertising as prescribed in article 56 (2) no. 9 of Medical Act should be reformed. It does not mean that the current interpretation of article 21 of the Constitution is agreeable. Though a commercial advertising is a way of communication and can be protected by article 21 (1) of the Constitution, it should not be under the prohibition of censorship prescribed by article 21 (2) of the Constitution. The Constitutional Court adopts the opposite view, however. It is doubtful that physician advertising needs some prior restraint, also. Of course, there exists severe informational asymmetry between physicians and patients and medical treatment might harm the life and health of patients irrevocably, so that medical treatment can be discerned from other services. It is civil and criminal liability for medical malpractice and duty to inform and not regulation on physician advertising, to address these differences or problems. Advance review should be abandoned and repelled, or substituted by more unproblematic way of regulation such as an accreditation of reviewed advertising or a self-regulation preformed by physician association independently from the Ministry of Health and Welfare or any other governmental agencies. Second, the substantive criteria for unfair physician advertising also should correspond that of unfair advertising in general. Some might argue that a learned profession, especially medical practice, is totally different from other businesses. It is performed under the professional ethics and should not persue commercial interest; medical practice in Korea is governed by the National Health Insurance system, the stability of which might be endangered when commercial competition in medical practice be allowed. Medical Act as well as the condition of medical practice market do not exclude competition between physicians. The fact is quite the opposite. Physicians are competing even though under the professional ethics and obligations and all the restrictions provided by the National Health Insurance system. In this situation, regulation on physician advertising might constitute unjustifiable restraint of competition, especially a kind of entry barrier for 'new physicians.'

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Breeding of 'Joyskin' Pear as fruit for Eating with the Skin (껍질째 먹는 배 '조이스킨' 육성)

  • Kim, Yoon-Kyeong;Kang, Sam-Seok;Cho, Kwang-Sik;Won, Kyung-Ho;Shin, Il-Sheob;Kim, Myung-Su;Ma, Kyeong-Bok;Lee, In Bog
    • Horticultural Science & Technology
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    • v.34 no.6
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    • pp.959-965
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    • 2016
  • In 1994, a new cultivar 'Joyskin' was created from a cross between the cultivars 'Whangkeumbae' and 'Waseaka' at the Pear Research Institute of the National Institute of Horticultural and Herbal Science, Rural Development Administration. In 2006, the 'Joyskin' was selected from among the 317 seedlings resulting from the cross for its skin and taste qualities. Regional adaptation tests were conducted in nine regions and in ten experimental plots from 2006 to 2011. The cultivar was named in 2011. 'Joyskin' showed a vigorous growth habit and semi-spread characteristics similar to 'Whangkeumbae'. The average full bloom date for 'Joyskin' was April 21st, which was also similar to 'Whangkeumbae'. The optimum fruit ripening time was September 6-8th, which was six or eight days earlier than 'Whangkeumbae'. The fruit was round in shape and the skin was a golden yellow color at maturity. The average fruit weight was 320 g and the flesh firmness was $2.5kg/8mm{\varphi}$. The firmness of the fruit skin determined by a blade-type plunger of texture analyzer was 22.9 N, which was significantly different from that of 'Whangkeumbae' 29.9N. Stone cell analysis of 'Joyskin' by phloroglucinol-HCl, showed that 'Joyskin' stone cells were small in size and few in numbers cpmpared to those of cultivars of was 'Manpungbae', 'Niitaka', and 'Whangkeumbae'. The patent application for 'Joyskin' was submitted in April, 2012 (Grant No. 2012-337). In 2016, 'Joyskin' (Grant No. 5895) was registered as a separate record, with uniformity and stability per Korean Seed Industry Law.

The Effects of Temperature on Maintaining the Stability of Water Quality in Biofloc-based Zero-water Exchange Culture Tanks (Biofloc을 기반으로 한 무 환수 사육 시스템의 수질 안정 유지에 미치는 수온의 영향)

  • Cho, Seo-Hyun;Jeong, Jong-Heon;Kim, Myung-Hee;Lee, Kyu-Tae;Kim, Dae-Jung;Kim, Kwang-Hyun;Oh, Sang-Pil;Han, Chang-Hee
    • Journal of Life Science
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    • v.25 no.5
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    • pp.496-506
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    • 2015
  • This study explored adequate water temperature ranges for maintaining stable water quality in a biofloc- based zero-water exchange culture system. Five experimental tanks with the following temperatures were set up: 10℃, 15℃, 20℃, 25℃, and 30℃. First, a biofloc-based culture system was developed in the experimental tanks; then, the tanks were stocked with goldfish and went without a water exchange for 60 days. Conditions for developing a biofloc-based culture system and stable water quality in low concentrations of inorganic nitrogen compounds at 10℃, 15℃, 20℃, 25℃, and 30℃ were maintained after 17, 26, 43, 68, and 78 days, respectively. Beginning from when the goldfish were stocked in the biofloc-based culture tanks, concentrations of $NH_4{^+}-N$ remained constant and at low levels at 10℃ and 15℃, but they showed a gradual increase at 20℃, 25℃, and 30℃. Concentrations of $NO_2{^-}-N$ and $NO_3{^-}-N$ at 10℃ and 15℃ did not remain at low levels and immediately increased. While $NO_2{^-}-N$ concentrations at above 20℃ remained constant and stable at relatively low levels, $NO_3{^-}-N$ concentrations showed a gradual increase. Conditions of 15℃ and below could not maintain low and stable concentrations of $NO_2{^-}-N$. In the pH range of 4.0 to 6.0, $NH_4{^+}-N$ concentration decreased as the pH rose. However, there was no correlation between pH and $NH_4{^+}-N$ concentration in the pH range of 6.0 to 8.0. These results indicate that pH levels should be kept at pH 6.0 and above to maintain a low and stable concentration of $NH_4{^+}-N$ at above 20℃.

Motion Analysis of Light Buoys Combined with 7 Nautical Mile Self-Contained Lantern (7마일 등명기를 결합한 경량화 등부표의 운동 해석)

  • Son, Bo-Hun;Ko, Seok-Won;Yang, Jae-Hyoung;Jeong, Se-Min
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.24 no.5
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    • pp.628-636
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    • 2018
  • Because large buoys are mainly made of steel, they are heavy and vulnerable to corrosion by sea water. This makes buoy installation and maintenance difficult. Moreover, vessel collision accidents with buoys and damage to vessels due to the material of buoys (e.g., steel) are reported every year. Recently, light buoys adopting eco-friendly and lightweight materials have come into the spotlight in order to solve the previously-mentioned problems. In Korea, a new lightweight buoy with a 7-Nautical Mile lantern adopting expanded polypropylene (EPP) and aluminum to create a buoyant body and tower structure, respectively, was developed in 2017. When these light buoys are operated in the ocean, the visibility and angle of light from the lantern installed on the light buoys changes, which may cause them to function improperly. Therefore, research on the performance of light buoys is needed since the weight distribution and motion characteristics of these new buoys differ from conventional models. In this study, stability estimation and motion analyses for newly-developed buoys under various environmental conditions considering a mooring line were carried out using ANSYS AQWA. Numerical simulations for the estimation of wind and current loads were performed using commercial CFD software, Siemens STAR-CCM+, to increase the accuracy of motion analysis. By comparing the estimated maximum significant motions of the light buoys, it was found that waves and currents were more influential in the motion of the buoys. And, the estimated motions of the buoys became larger as the sea state became worser, which might be the reason that the peak frequencies of the wave spectra got closer to those of the buoys.