• 대한한의학회지
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• 제25권2호
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• pp.1-8
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• 2004

Objectives : This study was performed to investigate the effects of Smilacis GlabraeRhizoma on antioxidation and antimicrobial activity. Methods : In this study, we investigated the effects of peroxide radicals on hydrogen donating activity and linoleic acid, and the MDA contents on the hepatic lipids of rats, via methanol extractions and subfractions of Smilacis Glabrae Rhizoma. Results : 1. Hydrogen donating activity was very great for the radical scavenging effects, depending on the additional concentration at the fraction level of chloroform and ethyl acetate. 2. The peroxide radicals in linoleic acid were lower depending on the additional concentration, at the fraction level of ethyl acetate, than the controls. We concluded that both had significant anti-oxidation effects. 3. MDA contents of the hepatic lipid had also inhibition effects on lipid radicals, in proportion to the concentration of n-hexane, chloroform, and ethyl acetate fraction level. 4. After extracting Smilads Glabrae Rhizoma with 80% methanol, we experimented with the extracts the antibiosis each concentration, for 5 bacilli, Bacilus subtilis, staphylococcus aureus, Escherichia coli, Salmonela typhimurium, and Alcaligenes faecalis. While the effects showed differentiations by concentration, they had usually the significant inhibition effect for the multiplication at 37.5~75ug/ml. To identify the effective constituents, we identified the antibiosis of the fractions assaying cyclically hexane, chloroform, ethyl acetate, and butanol. The result showed that antimicrobial activation of both Gram-positive and Gram-negative bacillus except for E. coli was measured highest at the fraction level of BuOH and water. Conclusions : This result suggest that the extractions of Smilacis Glabrae Rhizoma, at ethyl acetate fraction, had significant anti-oxidation effects and at BuOH and water fraction had relatively strong antimicrobial activity against Bacilus subtilis, staphylococcus aureus, Salmonela typhimurium, and Alcaligenes faecalis.

• Nuclear Engineering and Technology
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• 제51권5호
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• pp.1241-1250
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• 2019

This study mainly focused on the neutronics modeling of bubbles in bubbly flow in boiling water reactors. The bubble, ring and homogenous models were used for radial void fraction distribution. Effect of the bubble and ring models on the infinite multiplication factor and two-group flux distribution was investigated by comparing with the homogenous model. Square pitch unit cell geometry was used in the calculations. In the bubble model, spherical and non-spherical bubbles at random positions, sizes and shapes were produced by Monte Carlo method. The results show that there are significant differences among the proposed models from the viewpoint of physical interaction mechanism. For the fully-developed bubbly flow, $k_{inf}$ is overestimated in the ring model by about $720{\pm}6pcm$ with respect to homogeneous model whereas underestimated in the bubble model by about $-65{\pm}9pcm$ with a standard deviation of 15 pcm. In addition, the ring model shows that the coolant must be separated into regions to properly represent the radial void distribution. Deviations in flux distributions principally occur in certain regions, such as corners. As a result, the bubble model in modeling the void fraction can be used in nuclear engineering calculations.

• 한국수학교육학회지시리즈C:초등수학교육
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• 제22권2호
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• pp.129-147
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• 2019

본 연구에서는 CCSSM-CA와 그에 따른 미국 초등 교과서에 제시된 분수의 연산 내용을 분석하였다. 분석 결과, 분수를 단위분수나 분모가 같은 분수의 합으로 표현하게 하여 분수 개념과 연산을 연결 짓는 특징이 있었다. 또 분수의 곱셈에서는 곱하는 한 수의 크기에 기초하여 다른 수의 곱의 결과를 비교하도록 하거나, 나눗셈에서는 단위분수가 포함된 나눗셈을 먼저 다루고, 다양한 방법으로 계산을 하도록 제시하는 특징 등이 있었다.

• 대한수학교육학회지:학교수학
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• 제11권4호
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• pp.685-706
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• 2009

이 연구는 분수의 곱셈 나눗셈에 관련한 교수-학습을 의미 있게 도울 수 있는 맥락화가 왜 필요하며, 어떻게 가능한지, 또한 효과적인 맥락화의 활용 방안은 무엇인지를 탐구하는 것을 목적으로 한다. 이를 위해 자연수에 대하여 분수의 곱셈 나눗셈 상황의 차이는 무엇인지를 살펴보고, 그 차이에 따라 분수의 곱셈에서는 승수인 연산자의 역할을 이해할 수 이는 맥락을 설정하여, 단위의 변화에 대한 인식을 하도록 하였다. 분수의 나눗셈에서 포함제는 그 몫이 이산량인 경우이면 남은 양이 생길 수 있고, 연속량인 경우에는 분수로 그 몫을 표현해야 하는 맥락으로 구분지었다. 그리고 등분제의 맥락은 자연수의 등분제의 맥락과 연결시켜 새롭게 제시하여, 자연수의 나눗셈에서 분수의 나눗셈으로 형식화되는 3단계의 효과적인 학습 방법을 제안하였다. 이로써 교사와 학생들의 분수의 곱셈과 나눗셈의 교수-학습 과정에 있어서 유의미한 알고리즘의 습득에 도움을 줄 수 있을 것으로 기대한다.

• 대한미생물학회지
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• 제3권1호
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• pp.43-49
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• 1968

Japanese encephalitis(JE) shows its explosive epidemicity in the temperate zone of Asia but little is known on the overwintering mechanism. One of the hypotheses on the overwintering mechanism is that the virus overwinters in the hibernating animals. There has been no report on the proliferation of JE virus(JEV) or antibody formation in the snakes. The purpose of this experiment is to explore the mutual relationship between JEV and snake and to clarify whether JEV proliferates and induce antibody formation in snakes. Three species of non-poisonous common snakes were employed. Precipitation test was carried out after injecting calf serum and, HI and neutralization tests were done by injecting JEV into the snakes. The gamma globulin fraction of pre- and post-injection serum were compared by paper chromatography. According to the results, precipitating antibody reaction to calf serum could be observed only at $4^{\circ}C$. It was failed to demonstrate HI antibody formation but neutralizing antibody could be detected in one of the 9 snakes. Although antibody could not be detected in test-tube, tile result of paper chromatography shows the remarkable increase of gamma globulin fraction after the injection. Above results are strongly indicating the antibody formation in the snakes.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2014년도 추계학술대회
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• pp.10-11
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• 2014

In a 2-dimensional (2D) Discrete Cosine Transform (DCT) hardware, a significant fraction of the total hardware area is contributed by the combinational logic used to perform 1-dimensional (2D) transform. The size of the non-combinational logic i.e. the transpose memory is dictated by the size of the largest transform supported. Hence, the optimization of hardware area is performed mainly for 1D-transform combinational logic. This paper demonstrates the use of Multiple Constant Multiplication (MCM) algorithm to reduce the combinational logic area. Partial optimizations are also described for the cases where the direct use of MCM algorithm doesn't meet the timing constraint. Experimental results show that 46% improvement in gate count is achieved for 32 point 1D DCT transform logic after using MCM optimization.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 B
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• pp.778-780
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• 1999

Arithmetic unit speed depends strongly on the algorithms employed to realize the basic arithmetic operations.(add, subtract multiply, and divide) and on the logic design. Recent advances in VLSI have increased the feasibility of hardware implementation of floating point arithmetic units and microprocessors require a powerful floating-point processing unit as a standard option. This paper describes the design of floating-point multiplier for IEEE 754-1985 Single-Precision operation. Booth encoding algorithm method to reduce partial products and a Wallace tree of 4-2 CSA is adopted in fraction multiplication part to generate the $32{\times}32$ single-precision product. New scheme of rounding and sticky-bit generation is adopted to reduce area and timing. Also there is a true sign generator in this design. This multiplier have been implemented in a ALTERA FLEX EPF10K70RC240-4.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제16권4호
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• pp.245-263
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• 2012

The Korean mathematical curriculum has been changed three times during the resent five years. It led to changes in textbook system. In the 2007 revised mathematics curriculum, workbook was developed focusing on student's self-oriented learning, effective practice in differentiated classroom, and mathematics problem solving considering individual difference. This paper examines the characteristics of the tasks and the way the tasks are organized in the textbooks and the workbook in accordance with the 2007 revised mathematics curriculum; comparing with the function section before and after the amendment. Researchers examine whether the textbook and workbook were accomplished the purpose with "cognitive expectation", "level of cognitive demand", "and "response types". Researchers revised framework of [Son, J. W. & Senk, S. (2010). How reform curricula in the USA and Korea present multiplication and division of fraction. Educ. Stud. Math 74(2), 117-142] to make them suitable for the function section at the seventh grade.

• 한국수학교육학회지시리즈C:초등수학교육
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• 제3권1호
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• pp.63-77
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• 1999

We introduce what is the meaning of problem and problem solving and also different type of problems and problem-solving strategies were discussed in this paper, with suggestions for teaching both Polya's four-step strategy and specific problem solving strategies. Many real and concrete examples of routine and nonroutine problems in elementary school mathematics are introduced. Especially, we have researched on the actual condition how children in elementary school think about multiplication of fraction for the routine problem. As a result, we have noticed that children have diverse thinking in their own way and also concrete expressions are much better effective than algorithm showing in textbook.

• 대한수학교육학회지:학교수학
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• 제6권3호
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• pp.235-249
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• 2004

본 연구는 우리나라의 예비 초등 교사들이 분수 나눗셈 1$\frac{3}{4}$$\div$$\frac{1}{2}$에 적합한 문장제를 만들 때 나타나는 오류 유형과 만든 문장제의 유형을 분석한 것이다. 우리나라 예비 초등 교사들은 미국이나 중국의 교사들처럼 '$\frac{1}{2}$로 나누기'를 '2로 나누기'로 오해하는 일상 언어와 수학적 언어 사용의 불일치에 기인하는 구조적인 오류를 다수 보였으며, 계산결과만 생각하여 구조적으로 다른 1$\frac{3}{4}$$\times$2에 적합한 문장제를 만드는 새로운 유형의 오류도 보이고 있다. '포함제' 자체에는 익숙하지만 몫이 자연수가 아닌 분수 나눗셈 상황에서 포함제가 지니는 문제점에 대한 인식은 매우 부족한 것으로 나타났으며, '단위 비율의 결정', '곱셈의 역 상황'이라는 분수 나눗셈의 의미에 대한 이해가 매우 부족한 것으로 나타났다. 따라서 예비 초등 교사들을 위한 교육에서는 분수의 나눗셈에서 단위 비율의 결정, 곱셈의 역연산으로서의 나눗셈의 의미를 다양한 실제 상황 및 맥락과 관련지어 이해하게 하는 지도가 이루어질 필요가 있다.