• 한국수학교육학회지시리즈E:수학교육논문집
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• 제24권1호
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• pp.195-220
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• 2010

방진 또는 마방진(magic square, 魔方陣)은 정사각형 모양으로 수를 배열하여 가로, 세로, 대각선의 합이 같아지도록 만든 수배열을 말한다. 마방진의 '방'에는 정사각형이라는 의미가 포함되어 있다. 만약 '방' 즉 정사각형이라는 조건을 제거한다면 어떤 수배열이 가능할 것인가? 중국의 "양휘산법"과 "산법통종"에는 취오도(聚五圖)와 취육도(聚六圖), 취팔도(聚八圖), 찬구도(攢九圖), 팔진도(八陣圈), 연환도(連環圖)와 같은 다양한 수배열이 제시되어 있다. 또한 조선 시대 수학자 최석정의 "구수략"에는 지수귀문도(地數龜文圖)라는 독창적이고 아름다운 수배열이 제시되어 있다. 이밖에도 원 모양의 마방진, 별 모양의 마방진 등 다양한 마방진이 존재한다. 본고에서는 이러한 정사각형 형태가 아닌 마방진을 소개하고 이들이 갖는 몇 가지 성질과 이에 대한 활용 방법을 제시하였다.

• 대한토목학회논문집
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• 제29권2A호
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• pp.131-143
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• 2009

지진하중과 같은 횡하중에 대하여 교량구조물의 아칭작용은 교대 사이의 상부구조에 의해 발생하며 이를 상부구조의 저항능력이라고도 한다. 교량구조물의 아칭작용의 크기는 경간의 수에 영향을 받으며 또한 상부구조, 교대와 교각의 연결조건 및 상부구조와 하부구조의 강성비에도 영향을 받는다. 프리캐스트 콘크리트 상자형 교량의 비탄성 지진응답에 대한 아칭작용의 영향을 분석하기 위하여 경간수에 따른 두 가지 종류의 예제교량(교량 SB와 교량 LB), 교각의 높이의 배열에 따른 세가지 종류(대칭, 비대칭)의 교량, 상부구조와 하부구조의 연결조건에 따른 세가지 교량(형식 A, B, C)등에 대한 구분을 조합하여 18가지 종류의 예제구조물을 작성하였으며, 이 예제구조물들에 대하여 역량스펙트럼해석, 비탄성 시간이력해석을 수행하여 지진응답을 비교하여 아칭작용의 영향을 분석하였다. 아칭작용의 영향(최대변위의 감소와 저항능력의 증가)은 교량 SB(short bridge)의 경우가 교량 LB(long bridge) 보다 크게 나타났으며 대칭교량의 경우가 비대칭교량에 비하여 크게 나타남을 알수 있었다.

• Membrane and Water Treatment
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• 제7권4호
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• pp.297-311
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• 2016

Modeling and simulation of air humidification by hollow fiber membrane contactors are investigated in the current study. A computational fluid dynamic model was developed by solving the k-epsilon turbulence 2D Navier-Stokes equations as well as mass conservation equations for steady-state conditions in membrane contactors. Finite element method is used for the study of the air humidification under different operating conditions, with a focus on the humidity density, total mass transfer flux and velocity field. There has been good agreement between simulation results and experimental data obtained from literature. It is found that the enhancement of air stream decreases the outlet humidity from 0.392 to 0.340 (module 1) and from 0.467 to 0.337 (module 2). The results also indicated that there has been an increase in air velocity in the narrow space of shell side compared with air velocity wide space of shell side. Also, irregular arrangement has lower dead zones than regular arrangement which leads to higher water flux.

• 비교문화연구
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• 제38권
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• pp.385-404
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• 2015

Compiled in 776 by Zhang Shen, Wu Jing Wen Zi was regarded as the epitome of model book for standardized regular script in Tang Dynasty. Following early works like Shuo Wen Jie Zi, Zhang Shen adopted radical-rule for the compilation of this work. 3,250 characters were selected from the Five Classics and 160 radicals were established. Yu Jiaxi (1884-1955) harshly criticized the radical system of Wu Jing Wen Zi for being inconsistant and confusing. With careful review and analysis of examples from Wu Jing Wen Zi, this paper discusses the pupose of the compilation of this work, its unique radical-rule system, principles of arrangement of characters with the same or similar radicals, and the differentiation of variant characters. It further discusses the value of Wu Jing Wen Zi by its innovative radical-rule and effective differentiation of variant characters. It concludes with a rebuttal of Yu Jiaxi's argument and restate the necessity of reevaluation of this work even to this day.

• Entomological Research
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• 제48권5호
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• pp.429-438
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• 2018

Fine structural characteristics of the cardiac muscle and its sarcomere organization in the black widow spider, Latrodectus mactans were examined using transmission electron microscopy. The arrangement of cardiac muscle fibers was quite similar to that of skeletal muscle fibers, but they branched off at the ends and formed multiple connections with adjacent cells. Each cell contained multiple myofibrils and an extensive dyadic sarcotubular system consisting of sarcoplasmic reticulum and T-tubules. Thin and thick myofilaments were highly organized in regular repetitive arrays and formed contractile sarcomeres. Each repeating band unit of the sarcomere had three apparent striations, but the H-zone and M-lines were not prominent. Myofilaments were arranged into distinct sarcomeres defined by adjacent Z-lines with relatively short lengths of $2.0{\mu}m$ to $3.3{\mu}m$. Cross sections of the A-band showed hexagon-like arrangement of thick filaments, but the orbit of thin filaments around each thick filament was different from that seen in other vertebrates. Although each thick filament was surrounded by 12 thin filaments, the filament ratio of thin and thick myofilaments varied from 3:1 to 5:1 because thin filaments were shared by adjacent thick filaments.

• 노동경제논집
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• 제24권1호
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• pp.67-96
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• 2001

최근 3년에 걸친 경제위기 과정에서 노동시장에 나타난 가장 뚜렷한 현상은 노동시장의 비정규화이다. 저임금, 저조한 부가급부 혜택, 미비한 고용안정성 등 부정적인 특성을 갖는 비정규근로의 확산에 따라 이에 대한 보호논의가 전개되고 있으나 정의와 실태자료가 미비한 상태에서 엄밀한 연구는 많지 않다. 본고는 "한국노동패널" 자료에 포함된 임금근로자를 표본으로 전환회귀모형을 이용하여 고용형태의 선택식과 시간당 임금 결정식을 추정하고, 임금격차를 생산성 특성의 차이에 의한 임금격차와 임금차별의 두 요인으로 분해한다. 여성, 청년층, 고연령층, 저학력, 건강상 문제의 근로취약요인과 최근 경채위기 중 입직한 경우가 비정규근로률 선택할 확률을 높이는 것으로 나타난다. 비정규근로와 정규근로의 시간당 임금의 격차는 35%에 이르며 다른 임금절정요인을 통제하였을 때 고용형태별 임금격차는 19%에 이른다. Oaxaca에 따라 임금격차를 분해한 결과는 임금격차의 4분의 1 내지 3분의 1이 동일한 생산성 특성에 대하여 고용형태에 따라 체계적으로 상이한 가격을 지불하는 가격효과에 의한 것으로 나타난다.

• 한국지역사회생활과학회지
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• 제17권1호
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• pp.87-99
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• 2006

The purpose of this study was to explore the relationship between self-rated health and Activity of Daily Living (ADL) and self-care behavior of rural elderly in Korea, focused on the difference among three distinctive living arrangements; living alone, living only with his/her spouse, and living with their married children. For this purpose, data were gathered from a nationwide survey, a total of 586 elderly aged 65 or older and living in rural area, using the structured questionnaire. Also, self-care behavior were categorized into 4 groups; life-style practice, medical self-care, adaption to functional limitation, and emotional management. The major findings are as follows; 1) Rural elderly perceived their health little and more 'bad' but their ADL capacity were 'not difficult', especially among elderly living with spouse. 2) The level of 20 items in self-care behavior ($1{\sim}5$score) was ranged from 2.51 to 3.81 score. The behavior level of regular exercise, setting up additional phone, taking a nutrient, and testing BP or pulse regularly were low but that of taking a medicine according to prescription, close contact with other people, and regular eating were proportionally high. 3) The majority of self-care behavior were correlated with subjective health positively but medical self-care behavior were correlated with subjective health or ADL negatively. Based on these results, policy implications are discussed.

• 한국재료학회지
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• 제13권9호
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• pp.593-597
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• 2003

Anodic aluminum oxide (AAO) membrane was made of aluminum sheet (99.6%, 0.2 mm thickness). The regular array of hexagonal nano pores or channels were prepared by two step anodization process. A detail description of the AAO fabrication is presented. After the 1st anodization in oxalic acid (0.3 M) at 45 V, The formed AAO was removed by etching in a solution of 6 wt% $H_3$$PO_4$＋1.8 wt% $H_2$$CrO_4$. The regular arrangement of the pores was obtained by the 2nd anodization, which was carried out in the same condition as the 1st anodization. Subsequently, the alumina barrier layer at the bottom of the channel layer was removed in phosphoric acid (1M) after removing of aluminum. Pore diameter, density, and thickness could be controlled by the anodization process parameters such as applied voltage, anodizing time, pore widening time, etc. The pore diameter is proportional to the applied voltage and pore widening time. The pore density and thickness can be controlled by anodization temperature and voltage.

• 한국가금학회지
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• 제11권1호
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• pp.33-39
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• 1984

The pattern of economic integration in the broiler industry can be grouped into three categories; 1) non-integration, 2) quasi-integration and 3) complete-integration. It is general to see that the non-integration is quite common under the market conditions of perfect competition, whereas the complete integration is more preferable in the imperfect competition. The quasi-integration, however, exists at all phases where the complete integration is not fully formed and implemented, but the non-integration has begun to alter its nature into integrated structure. The broiler industry in Korea has been characterized with the typically non-integrated independent operation, resulting in considerable price fluctuation and unstable industry as a whole. As a means of solving out the problem stemed from the non-integrated, growers and agribusinessmen involved in broiler industry have tended to develope the regular customer relationship prevailed between two parties. In fact, it has been practiced for years that most growers have been dealt with factor suppliers or processors on a regular basis for advantages of better price and quality, useful information, management help and so forth. Under the customary transaction, no formal contract has been made due to simple buyers and sellers relations, not like the one used to be performed in the form of contractual agreement. The broiler industry realizes the direction to go ahead toward the formal arrangement of integrated system from current regular transactions. As more Vowers, suppliers and processors recognize the necessity of it, the non-integrated industry appears to become the partially integrated by developing the existing customer relationship in such a way that functions of integrators are. further expanded and better organized. As a result, a type of quasi-integration started to show up by an integrator dominated in the field of hatching, feedmilling, dressing and by a grower's coop, It is concluded, therefore, that the evolution of quasi-integration in Korea's broiler industry is continuously taking place, implying the close approach to the completely integrated broiler production and marketing system.

• Journal of Periodontal and Implant Science
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• 제26권1호
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• pp.255-265
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• 1996

The purpose of the present study is to evaluate dimensional consistency, bristle finishes and bristle rebound rate of four brands of $Dentichek^{(R)}$ toothbrushes(regular-male, regular-female, soft-male, soft-female) to provide referneces in product enhancement and quality control for the manufacturer and to provide suggestions in selecting appropriate toothbrushes for general public. The results are as follows : 1. The size of the head is : $25.10{\times}8.10mm$ for male toothbrushes and $19.90{\times}8.10mm$ for male toothbrushes, while the size of the bristle portion is: $29.90{\times}10.65mm$ for male toothbrushes and $25.25{\times}10.65mm$ for female toothbrushes. 2. The length of the bristles is 10.70mm in all four groups. 3. The length of the toothbrush is 192mm in all four groups. 4. The number of tuft is 43 for male toothbrushes and 35 for female toothbrushes. Tuft arrangement is 4-row configuration in all four groups. 5. The number of bristles in a tuft ranges from 40-56, with higher numbers in male toothbrushes compared to the female counterparts, and higher numbers in the "soft" variety compared to the regular ones. 6. The diameter of the bristle is : 0.21mm for the outer row and 0.19mm for the inner row in the regular brand, and 0.17mm for the soft brand. 7. Irregularly finished bristle ends comprised 20-22% of the total bristles. 8. The bristle rebound rate ranges from 55.9% to 62.3%, with higher numbers in the "soft" variety compared to the regular ones. The above results show that $Dentichek^{(R)}$ toothbrushes meet the requirements of Korean Dental Association standards for toothbrushes, but further evaluations of their effects on periodontium and plaque elimination in actual in-use situation may be needed.