• 생명과학회지
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• 제9권3호
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• pp.333-340
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• 1999

The toxic effect of TBTO on Chlorella and Rotifer was observed. The value of 48hr-LC50 for Chlorella (3.3$\mu\textrm{g}$/L) estimated to be almost 500 times as high as that for Rotifer (6.7ng/L). A fertilized egg of olive flounder exposed in an embryo-formation stage was mostly influenced by TBTO toxicity when the fertilized egg at each stage until hatching was exposed to TBTO at the concentrations of 5 to 200ng/L. The values of LT50 were estimated to be 68.0, 41.0, 21.0, 13.0, 7.7 and 4.7 hours at 5, 10, 25, 50, 100 and 200ng/L of TBTO, respectively when the fertilized egg in a morula stage was exposed to TBTO, and the 48hr-LC50 was 8 ng/L. In case of TBTO treatment in an embryo-formation stage, the values of LT50 were 33.0, 12.5, 3.5, 1.3, 0.5 and 0.2 hours at 5, 10, 25, 50, 100 and 200ng/L of TBTO, respectively, and the value of 48hr-LC50 was 4ng/L. The values of LT50 were estimated to be 17.0, 11.0, 6.2, 4.0, 2.6 and 1.7 hours at 5, 10, 25, 50, 100 and 200ng/L of TBTO, respectively when the fertilized egg in a stage just before hatching was exposed to TBTO, and the 48hr-LC50 was below 1ng/L. The percentages of hatching were 46.2, 20.6, 21.9, 20.6 and 13.2% at 25, 50, 100, 250 and 500ng/L of TBTO, respectively when the fertilized egg in the stage just before hatching was exposed to TBTO and the measurement was done at second day after the completion of hatching. However no survival after the completion of hatching was found in all cases. With the treatment of 1, 5 and 10ng/L of TBTO, the percentages of hatching were 80.5, 70.0 and 44.1%, respectively. The percentages of survival until second day after the completion of hatching were 80.0, 63.3 and 9.1%, respectively. The percentages of hatching and survivability after the completion of hatching for the control were 84.5 and 82.5%, respectively.

• Journal of Welding and Joining
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• 제19권3호
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• pp.325-333
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• 2001

The effect of base metal grain size on isothermal solidification behavior of Ni-base superalloy, CMSX-2 during transient liquid phase (TLP) bonding was investigated employing MBF-80 insert metal. TLP-bonding of single crystal. coarse-grained and fine-grained CMSX-2 was carried out at 1373∼1548k for various holding time in vacuum. The eutectic width diminished linearly with the square root of holding time during isothermal solidification process for single crystal, coarse-grained and fine-grained base metals. The completion time for isothermal solidification decreased in the order ; single crystal, coarse-grained and fine-grained base metals. The difference of isothermal solidification rates produced when bonding the different base metals could be explained quantitatively by the effect of base metal grain boundaries on the apparent average diffusion coefficient of boron in CMSX-2.

• Progress in Superconductivity
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• 제9권2호
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• pp.188-192
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• 2008

We investigated the size effect on quench development in $Au/YBa_2Cu_3O_7$ (YBCO) thin film meander lines on sapphire substrates. The meander lines were fabricated by patterning YBCO films coated with gold layers. The lines were subjected to simulated AC fault current, and immersed in liquid nitrogen during the experiment. After the initial rapid rise, the resistance increased moderately and then slowly. In 4 inch-diameter meander lines, the period during which the resistance increased moderately was considerably longer than in 2 inch-diameter line. Moderate increase of resistance was originated from quench propagation. The film temperature was about 180 K at the point when the propagation was completed. The rate of resistance increase after the quench completion was not affected by the film size.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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• pp.504-510
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• 2009

Dredging and Reclamation which have been conducted steadily for creation of new coastal area have demerit that takes a long time. Hence, a lot of researches on acceleration of self-weight consolidation is proceeding continuously. In this paper, 30 cases of laboratory self-weight consolidation tests were conducted to understand application of PDF method, one of the self-weight consolidation acceleration methods, to domestic dredged soils. Acceleration effect of self-weight consolidation was confirmed through comparison and analysis on completion time and settlement of self-weight consolidation for none installed case and 4 kinds of common used PBD installed cases.

• ETRI Journal
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• 제36권6호
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• pp.979-987
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• 2014

This paper describes new tactile feedback patterns and the effect of their input performance for a button GUI activated by a tap gesture on mobile touch devices. Based on an analysis of touch interaction and informal user tests, several tactile feedback patterns were designed. Using these patterns, three user experiments were performed to investigate appropriate tactile feedback patterns and their input performance during interaction with a touch button. The results showed that a tactile pattern responding to each touch and release gesture with a rapid response time and short falling time provides the feeling of physically clicking a button. The suggested tactile feedback pattern has a significantly positive effect on the number of typing errors and typing task completion time compared to the performance when no feedback is provided.

• 대한지역사회영양학회지
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• 제17권6호
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• pp.752-771
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• 2012

This study was conducted to investigate the effect of sodium reduction education program of a public health center on the blood pressure, blood biochemical profile and sodium intake of hypertensive adults. The program continued for 16 weeks with an 8-week nutrition education and an 8-week follow-up to forty two subjects, 6 males and 36 females aged 46 to 80 years. Subjects received nutrition education including lectures, activities, cooking classes and nutrition counseling. Physical fitness, management of stress, and nutrition counseling were provided during the follow-up. The program was evaluated three times, before and after the nutrition education, and after the follow-up. Systolic blood pressure (p < 0.0001) and diastolic blood pressure (p < 0.001) were decreased after completion of the program. Body weight (p < 0.005), percent body fat (p < 0.005) and body mass index (p < 0.001) were decreased, too. There were no significant differences in blood glucose, HDL-cholesterol and triglycerides, while elevated levels of total cholesterol (p < 0.001) and LDL-cholesterol (p < 0.001) appeared after the program completion. Decreased intakes of vitamin A (p < 0.05), ${\beta}$-carotene (p < 0.001) and sodium (p < 0.001) were observed. Consumption frequency of noodles, soups, stews, kimchi, fishes/shellfish, seasoned vegetables, and salted seafoods/pickles (p < 0.05~p < 0.001) were decreased, while that of all food groups were not changed during the follow-up. Total score of nutrition knowledge related to sodium intake and hypertension (p < 0.001), and that of dietary behavior associated with high sodium intakes were changed positively (p < 0.001) only during the nutrition education. This sodium reduction education program, including the follow-up study showed positive effects on the blood pressure, sodium intake, nutrition knowledge and dietary behavior of hypertensive adults.

• 한국멀티미디어학회논문지
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• 제19권8호
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• pp.1337-1344
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• 2016

As the visual effect frequently used in movies or animations, special effects are well suited for the creation of buildings or materials' destruction and collapse scenes. With the relevant programs developing technologically, the adoption of a real-time physically based-system makes it possible to realistically express dynamic simulations. In the large scale, the visual expression of such effects of destroying is satisfying enough, but most common programs of those effects fail to maximize visual effect generated with the cutting of small materials. Besides, to perform a heavy simulation process needs high-performance hardware and programs, where high costs would become a serious issue. For this reason, this paper suggests a solution optimized for the effect of small materials-cutting. The progress of each step shows technologies which trace movement with the state of the completion of the character's motions and then cut the material in real-time, finally led to the very realistic visual effect. Besides, using vector inner calculation to follow the motions of object and to realize cutting effect, this study provides an experiment that constructs visual effect for visualization from the basis of mathematical algorithm and it would be certainly as an educational material used for further researches.

• 유통과학연구
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• 제19권3호
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• pp.25-34
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• 2021

Purpose: The purpose of this study is to analyze the economic ripple effect(ERE) of logistics industry by construction of Trans-Korea Railway (TKR) and present policy measures to minimize the economic loss of South Korea (SK). Research design, data and methodology: As the analysis method, exponential smoothing was used for demand forecasting, Input-Output analysis was used to estimate the economic ripple effect coefficient, and scenario analysis was used to an efficient way to invest in TKR to minimize SK's economic losses. Results: 1) the production(logistics fares) of TKR for 10 years after its completion is about 11.42 trillion won in positive relations, and 26.89 billion won in negative relations. 2) the ERE of SK in positive relations is 24.32 trillion won in production inducement effect, 8.1 trillion won in value-added inducement effect, 3.54 trillion won in import inducement effect, and 70,930 persons in employment inducement effect. But the ERE was insufficient in the negative relations. 3) SK's efficient investment method is providing materials and equipment by SK and building the TKR by North Korea in positive inter-Korea relations. Conclusions: For the successful operation of TKR, international cooperation, legalization and stable peace settlement on the Korean Peninsula are required.

• 컴퓨터교육학회논문지
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• 제22권2호
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• pp.39-50
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• 2019

본 논문에서는 효과적인 컴퓨터 프로그래밍 학습을 위하여 팀 프로젝트 기반 학습을 설계하여 적용하고 학습효과에 미치는 영향을 분석하였다. 이론 강의 및 실습 최소화, 무작위 추첨에 의한 팀 구성, 각 팀원별 책임과 권한의 설정, 주어진 과제에 대한 경쟁 방식 문제 해결 프로젝트 진행, 팀 프로젝트가 끝날 때까지 매주 단계별 진행사항 발표를 통한 자연스러운 정보 공유 및 학습 사이클 반복 등을 통하여 학생들이 능동적으로 학습에 참여하는 모습이 관찰되었다. 과정 종료 후, 학습효과에 대한 분석을 위하여 학습자를 대상으로 설문조사를 실시하였으며, 그 결과 팀 프로젝트 기반 교육이 컴퓨터 프로그래밍 학습에 긍정적인 영향을 미치는 것으로 파악되었다. 본 논문에서는 도출된 요인 간 관계분석을 바탕으로 보다 효과적인 컴퓨터 프로그래밍 학습 방법을 논하고자 한다.

• 한국환경보건학회지
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• 제35권5호
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• pp.417-425
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• 2009

The purpose of this study was to investigate the whitening effect of Angelicae dahuricae Radix water extract (ADWE) by its application on artificial tanning spots which were induced by 1,500 $mJ/cm^2$ of UVB radiation on the backs of brown guinea pigs weighing approximately 450~500 g. Thirty ${\mu}l$ of ADWE, at each application, were applied twice a day, 5 days a week, for 8 weeks to the guinea pigs. The artificial tanning spots were divided into 3 groups which were vehicle control group [propylene glycol: ethanol: water (5:3:2)], positive control group (2% hydroquinone) and experimental group (2% ADWE). The visible whitening effect and changes in melanin index were evaluated once a week. On completion of the experiment, the animals were sacrificed under anesthetization, and the artificial tanning spots were excised by biopsy punch and stained with Hematoxylin and Eosin (H&E) to observe histological change and also stained with Fontana-Masson's silver (F-M) and S-100 to observe melanin pigmentation and melanocytes. In the gross observation, the experimental group showed higher pigmentation than the positive control group but lower pigmentation than the vehicle control group. Histological observation confirmed that ADWE had a positive whitening effect by showing a lower distribution of melanin and melanocytes in the epidermis of experimental group than in the vehicle control group.