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        검색결과 1,616

        421.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The objective of this study is to develop an optimized method of mix design for rapid-set lightweight-formed mortar mix. To achieve this objective, the workability, setting time, and compressive strength of mixes under various conditions of mix design were evaluated. METHODS: The water-bonder ratio, fly-ash substitution ratio, and forming agent injection amount were selected as design variables in the study. The fluidity, setting time, density, and strength of the mortar mix were considered as major evaluation criteria of the mixture, and were subsequently utilized to evaluate the characteristics of the mortar mix under various conditions. RESULTS : The observations made from the mix design process are as follows: 1) the air content and fluidity increase as the forming agent ratio and forming agent ratio increase, respectively; 2) the maximum air content is approximately 20%; 3) the accelerating agent decreases the fluidity of the mortar mix by 15% on average; 4) the forming agent injection ratio and fly-ash substitution ratio yield significant effects on the initial and final set times of the mortar mix; 5) as the forming agent injection ratio and fly-ash substitution ratio increase, the compressive strength of the mortar mix decreases; and 6) the 28-day compressive strengths of the forming agent injection ratio and fly-ash substitution ratio yield the most significant effects. CONCLUSIONS: It is concluded that the governing design variables for the rapid-set lightweight-formed mortar mix are the forming agent injection ratio and fly-ash substitution ratio.
        4,000원
        422.
        2017.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Seismic analyses of a pile under a large rigid basement foundation embedded in the homogeneous soil layer were performed practically by a response displacement method assuming a sinusoidal wave form. However, it is hard to take into account the characteristics of a large mat foundation and a heterogeneous soil layer with the response displacement method. The response displacement method is relevant to the 2D problems for longitudinal structures such as tunnel, underground cave structure, etc., but might not be relevant with isolated foundations for building structures. In this study, seismic pile analysis by a pseudo 3D finite element method was carried out to compare numerical results with results of the response displacement method considering 3D characteristics of a foundation-soil system which is important for the building foundation analyses. Study results show that seismic analyses results of a response displacement method are similar to those of a pseudo 3D numerical method for stiff and dense soil layers, but they are too conservative for a soft soil layer inducing large soil pressures on the foundation wall and large pile displacements due to ignored foundation rigidity and resistance.
        4,000원
        423.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        환경부 지정 멸종위기 II급 종인 남생이의 복원을 위하여 개체증식 프로그램들을 개발해왔지만, 남생이의 번식생리에 대한 이해는 여전히 부족한 상태이다. 본 연구에서는 2014년 11월부터 2015년 10월 사이에 동면을 한 개체와 동면을 하지 않은 개체를 이용하여 성호르몬, 여포와 알의 수와 크기, 암ž수간의 행동상호작용의 계절적 변화를 연구하였다. 비록 동면 여부에 따라 다소의 편차는 있었지만, 암컷의 혈청 에스트라디올 농도는 7월부터 증가하기 시작하여 8월-10 월에 최고 농도를 보였으며, 수컷의 테스토스테론의 농도는 8-9월에 최고 농도를 보였으며, 3월에 가장 낮았다. 동면을 한 암컷들은 5월초에서 7월 중순 사이에 완전히 발달한 알을 가지고 있었으며, 산란은 6월 초순부터 7월 하순 사이에 이루어졌다. 반면, 동면을 하지 않은 암컷들은 이른 4월부터 이른 6월 사이와 8월 중순에서 11월 하순 사이에 알을 가지고 있었으며, 산란은 6월초, 10월 중순, 2월 초에 이루어졌다. 이러한 결과는 동면이 여포와 알의 정상적인 발달에 매우 중요한 역할을 함을 보여준다. 행동연구에서 암ž수간의 구애행동을 포함하는 행동상호작용은 8월 하순부터 증가되 어 10-11월에 최대를 보였다. 연구결과는 남생이의 짝짓기 기간이 성호르몬의 증가와 직접 연계되어 있지만, 여포와 알의 발달은 그렇지 않다는 것을 보여준다. 이러한 연구결과는 멸종위기종인 남생이의 성공적인 번식프로그램을 운영 하는데 매우 중요하게 사용될 것으로 판단된다.
        4,000원
        424.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The analysis on the international safety management code (ISM Code) and case of foreign national safety management for fishing vessel was conducted to serve as a basic data on the introduction of safety management system (SMS) for a deep-sea fishing vessel in Korea. As a result, Maritime New Zealand (MNZ) has managed operations of SMS in the maritime rules according to the Maritime Transport Act since 1994. MNZ underwent a safe ship management (SSM), which includes elements applied to shipping companies, ship and verification of the ISM Code for ships, except ISM Code application since 1998. In 2014 the introduction of the advanced maritime operator safety system (MOSS) superior to the SSM by MNZ was promoted actively switch and enforcement. Meanwhile, the safe operation manual of Japanese fishing vessel includes large part of the contents of the ISM Code, and voluntary implementation to fit the realities of the fishing vessel. The law application of SMS for a deep-sea fishing vessel after the newly establishment of the Ocean Industry Development Act to SMS would be advantageous to the schematic management, supervision, maintenance and application and, in 2016 from the implementation of maritime safety supervisor for a deep-sea fishing vessel that the management and supervision through the fishing vessel will be the efficient operation. The configuration of the safety management system in a deep-sea fishing vessel should be included as an element of ISM Code. The introduction of such a system is gradually applicable, such as nationality overseas vessel case study of the ISM Code, and vessels that are excluded from the application will be implemented as autonomous as Japan. The results are expected to contribute to sustainable development in the ocean industry safety culture spread throughout the ocean industry through the enhancement of safety fishing competency and safety management responsibility of fisher.
        4,000원
        425.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        OBJECTIVES: This study is to develop the optimum mixing proportions for cement concrete pavement with using recycled aggregates. METHODS: The mixture varied recycled coarse aggregates content from 50 % to 100 % to replace the natural coarse aggregates by weight. Tests for fundamental properties as a cement concrete pavement were conducted before and after hardening of the concrete. RESULTS: It was found that the variation in the amount of the recycled aggregate affected the compressive and flexural strength development, as well as the chloride ion penetration resistance. As the amount of the recycled aggregate content increased the compressive and flexural strength and the resistance to chloride ion penetration decreased. However, the resistance to freeze-thaw reaction was affected significantly. In addition, the gradation of the aggregate became worse and hence so did the coarseness factor as the recycled aggregate amount increased. CONCLUSIONS : The fundamental properties of the concrete with recycled aggregate does not seem to be appropriate when the recycled aggregate quality is not guaranteed up to a some level and its replacement ratio is over 50%. The optimized gradation of the aggregates should also be sought when the recycled aggregate is used for the cement concrete pavement materials.
        4,000원
        426.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We summarize our preliminary study on the research cooperation method in the astronomy field between Republic of Korea (South Korea) and Democratic People's Republic of Korea (North Korea). To investigate the recent astronomical activities of North Korea, we have surveyed the published records of research papers and international collaborations associated with North Korean astronomers. We found only 4 astronomical papers among the identified 260 SCI papers related to North Korean researchers for the past 11 years. North Korean astronomers had very few interactions with the international astronomical society before rejoining IAU in 2012. Recently, North Korea made several astronomical research exchanges with China and Netherlands. They seemed to attend several international conferences and present their research results. We have studied possibilities to establish international networks to encourage the cooperation between South and North, and suggest to start collaboration in the historical astronomy. The collaboration can be expanded gradually to other fields in astronomy. There are many obvious political difficulties to have interactions with North Koreans. However, it will be necessary to make a long-term plan considering the reunification.
        4,000원
        428.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Secure operation of hospitals during and right after earthquake is essential. Past lessons from earthquake damages have shown that most of the injured and the death occurred within 30 minutes after earthquake and the portion of nonstructural damage has become significant. However, hospital buildings in Korea have not prepared fully to address such rising issues. This paper is to study what type of damage patterns are related to hospital buildings and how to develop a preparedness plan to keep hospitals operational at all earthquakes if possible. This paper first reviews on past earthquake damages reported as critical to hospital buildings while classifying them into four groups: (1) structural element; (2) architectural-nostructural element; (3) medical equipments and contents; and (4) utility facility. Upon such classification, some detailed concerns can be specified under each group explicitly. Then a hierarchy for hospital building is also developed for the classified groups, which enables us to identify required things for the enhancement of seismic performance of hospital building that consists of heterogeneous elements. To upgrade the level of seismic performance for existing hospital buildings, the concept of performance-based approach can be adopted to address the heterogeneous problems in a systematic and stepwise manner. Finally a conceptual framework for the seismic risk assessment for hospital building is proposed toward the seismic enhancement of hospital buildings using performance-based approach.
        4,000원
        429.
        2016.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 연구는 기초의 묻힘이 면진 원전구조물의 응답에 미치는 효과를 지표기초와 비교하여 평가하였다. 면진장치의 비선형 성을 고려한 비선형 SSI 해석은 진동수영역해석과 시간영역해석의 복합법인 경계반력법(BRM)을 이용하여 수행하였다. BRM 해석모델은 BRM을 이용한 등가선형 SSI 해석결과를 재래의 주파수영역 SSI 해석결과와 비교함으로 검증하였다. 마 지막으로 비선형 SSI해석에 의한 묻힌기초 모델의 면진장치의 변위 및 구조물 응답을 지표기초의 해석결과와 비교하였다. 비교결과, 면진장치의 변위응답은 묻힌기초효과를 고려할 경우 감소할 수 있음을 알 수 있었다.
        4,300원
        430.
        2016.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Kunrak, a type of Korea traditional cheese, is made using Tarak, a yogurt produced with makgeolli as the fermentation source. Kunrak is produced by removing whey from Tarak, followed by drying process for safe storage and consumption over a longer period. In this study, we produced kunrak based on the method described in「Imwonsibyukji」. Prepared Kunrak was ripening for 96 hours at 20, 30, and 40oC. In order to study characteristics of Kunrak, physiochemical properties (pH, acidity, water contents) and contents of metabolites (organic acids, sugars, amino acids, and fatty acids) were analyzed. During ripening, water contents decreased. The main organic acids in Kunrak were citric acid and lactic acid, and the main free sugar was lactose. Main amino acids were glutamate and phenylalanine, and main fatty acid was saturated capric acid. At later ripening, all metabolites increased immediately after preparation. The sensory evaluation score of overall preference was highest for Kunrak, which was ripening at 40oC for 96 hours. This study was aimed to assay metabolites of Kunrak under various ripening conditions. The results provide basic data to produce conditions for standardized manufacturing of Kunrak.
        4,000원
        431.
        2016.10 구독 인증기관·개인회원 무료
        농업사회, 산업사회, 정보화 사회를 거쳐 이제 인류는 인공지능, 생체 조작, 로보틱스, 사물인터넷, 3D 프린팅과 하드웨어 및 소프트웨어 융합으로 대변되는 제4의 물결 혹은 4차 산업혁명기로 접어들고 있다. 한국도 빠른 추격자의 접근 방식으로 집중적 고속성장을 이루어 낸 반도체, 디스플레이, 스마트폰 등의 IT 산업과 바이오융합의 새로운 흐름에서 이제 혁신적 신기술 개발과 함께 새로운 패러다임에 적응해야 하는 숙제를 안고 있다. 자연친화적 지속가능성 과 에너지 효율적 시스템이 중요하게 대두되는 미래기술은 사실 자연에서는 오랜 기간 진화해온 생물의 적응전략과 기능성, 그리고 생태학적 원리와 그 흐름을 같이 한다. 나노 및 마이크로 기술, IT 기술, 바이오 기술의 융합적 발전은 자연의 오랜 지혜를 구현하여 인간생활에 응용할 수 있는 기반을 이루어 자연모사 혹은 생체모방 기술은 미래기술의 중요한 접근 방식이 되고 있으며 곤충학을 비롯한 기초생태학과 응용기술의 만남은 그를 위한 핵심적 가치를 창출하게 되리라 기대된다. “본 연구는 미래창조과학부 및 정보통신기술진흥센터의 ICT명품인재양성사업의 연구결과로 수행되었음”(IITP-R0346-16-1008)
        432.
        2016.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The objective of this study is to evaluate the effect of size and depth of cavities on the pavement failure using the full-scale accelerated pavement testing. METHODS: A full-scale testbed was constructed by installing the artificial cavities at a depth of 0.3 m and 0.7 m from the pavement surface for accelerated pavement testing. The cavities were made of ice with a dimension of 0.5 m*0.5 m*0.3 m, and the thickness of asphalt and base layer were 0.2 m and 0.3 m, respectively. The ground penetrating radar and endoscope testing were conducted to determine the shape and location of cavities. The falling weight deflectometer testing was also performed on the cavity and intact sections to estimate the difference of structural capacity between the two sections. A wheel loading of 80 kN was applied on the pavement section with a speed of 10 km/h in accelerated pavement testing. The permanent deformation was measured periodically at a given number of repetitions. The correlation between the depth and size of cavities and pavement failure was investigated using the accelerated pavement testing results. RESULTS : It is found from FWD testing that the center deflection of cavity section is 10% greater than that of the intact section, indicating the 25% reduction of modulus in subbase layer due to the occurrence of the cavity. The measured permanent deformation of the intact section is approximately 10 mm at 90,000 load repetitions. However, for a cavity section of 0.7 m depth, a permanent deformation of 30 mm was measured at 90,000 load repetitions, which is three times greater than that of the intact section. At cavity section of 0.3 m, the permanent deformation reached up to approximately 90 mm and an elliptical hole occurred at pavement surface after testing. CONCLUSIONS : This study is aimed at determining the pavement failure mechanism due to the occurrence of cavities under the pavement using accelerated pavement testing. In the future, the accelerated pavement testing will be conducted at a pavement section with different depths and sizes of cavities. Test results will be utilized to establish the criteria of risk in road collapse based on the various conditions.
        4,000원
        433.
        2016.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: This study identifies the causes and the mechanism of the occurrence of underground cavities. METHODS: A case study on cave-in and a series of model tests with a small soil chamber were conducted. RESULTS: A hypothesis about the mechanism of the cave-in in road was established, and the basic influencing factors on underground cavity expansion were identified. CONCLUSIONS: It was found that the characteristics of shear strength of soil and direction of water flow had a larger influence on cavity formation and expansion than the characteristics of internal erosion. In addition, large cavities suddenly expanded when cavities were caused owing to breakage of buried sewer pipe.
        4,000원
        434.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Soil-foundation-structure interaction (SFSI) is one of the important issues in the seismic design for evaluating the exact behavior of the system. A seismic design of a structure can be more precise and economical, provided that the effect of SFSI is properly taken into account. In this study, a series of the dynamic centrifuge tests were performed to compare the seismic response of the single degree of freedom(SDOF) structure on the various types of the foundation. The shallow and pile foundations were made up of diverse mass and different conjunctive condition, respectively. The test specimen consisted of dry sand deposit, foundation, and SDOF structure in a centrifuge box. Several types of earthquake motions were sequentially applied to the test specimen from weak to strong intensity of them, which is known as a stage test. Results from the centrifuge tests showed that the seismic responses of the SDOF structure on the shallow foundation and disconnected pile foundation decreased by the foundation rocking. On the other hand, those on the connected pile foundation gradually increased with intensity of input motion. The allowable displacement of the foundation under the strong earthquake, the shallow and the disconnected pile foundation, have an advantage in dissipating the earthquake energy for the seismic design.
        4,000원
        435.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        해상에서는 UN산하 IMO(International Maritime Organization, 국제해사기구)는 선박에서 배출하는 CO₂량을 2030년까지 30 %까지 줄이는 것을 목표로 설정하고 있다. 본 연구는 이러한 상황에 대응하고 친환경기술의 개발을 목표로 선박용 내연기관에서의 폐열을 이용하는 열전발전시스템 개발에 최종목표를 두고, 본 논문에서는 선박용 열전발전시스템 개발에 앞서 기초 열해석을 실시하고 분석하였다. 그 결과 다음과 같은 열전발전시스템의 효율향상에 관한 유효한 방법을 얻어 낼 수 있었다. 1) 고온측 열원과 모듈간 온도차를 줄여 모듈의 온도차를 늘리는 것으로 열전발전시스템의 효율이 8.917 %로 향상되는 것을 알 수 있었다. 2) 외부부하저항의 변화에 따른 시스템 효율은 약 6 %로 그 변화폭이 크게 발생하지 않는 것을 확인할 수 있었다. 3) 동일 계산 조건에서 방형관의 재질이 스테인레스인 경우의 시스템 효율이 8.707 %로 두랄루민(8.605 %), 동(8.607 %)보다 높을 것을 확인할 수 있었다.
        4,000원
        436.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 2차원 나노 물질을 응용하여 수처리 막의 성능을 향상시킬 수 있는가에 대한 연구가 활발하다. 그 노력의 한 가운데에 원자 두께를 가지고 있으면서 손쉽게 구할 수 있고 층으로 쌓을 수도 있는 2차원 물질인 그래핀이 자리하고 있다. 이 총설에서 우리는 그래핀으로부터 만들 수 있는 두 가지 막 구조에 관한 기초 물질 전달 현상을 최근 연구 성과를 중심으 로 다룬다. 그 물질 자체로 이미 물질 전달 차단성을 갖는 그래핀에 정확히 제어된 크기의 구멍을 뚫을 수 있다면 아마도 원 자 크기 수준으로 얇은 두께 때문에 그래핀 막은 같은 기공 크기의 어느 막보다도 빠른 궁극적 투과도를 나타낼 것이며, 이 로부터 선택도를 담보할 수 있다면 다양한 막 분리 공정에 적용할 수 있을 것이다. 그 한 예로, 나노미터 이하의 기공을 가정 한 초박막 침투성 그래핀 막에 대한 분자동역학 연구와 몇몇 초기 실험 결과들이 해수담수화 막으로서의 가능성을 보인 점은 주목할 만하다. 그래핀 물질로부터 다른 구성을 가진 막을 설계할 수 있는데, 이 막은 적당히 산화된 그래핀 마이크로 판들을 무작위로 적층함으로써 구현할 수 있다. 그래핀 판 적층 간격을 나노미터 이하로 쉽게 제어할 수 있기 때문에 이 구조 역시 수처리 및 해수담수화 막으로서의 가능성을 시사한다. 기존 막기술에 존재하지 않던 구조와 물질 전달 성질을 가짐으로써 두 종류의 그래핀 막은 앞으로 수처리 기술을 비롯한 다양한 막 기술의 응용분야에서 효과적으로 기여할 가능성이 충분하다.
        4,600원
        437.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: In this study, we evaluated changes in the retroreflectivity and luminance of phosphorescent road line markings with changes in glass beads and line marking thickness. METHODS : The color of line markings affects their retroreflectivity. Using a chromaticity test, we conducted the analysis of whether phosphorescent road line markings adhered to the「 KS M 6080」standard. Then, we measured the dry retroreflectivity and wet retroreflectivity for various glass bead refractive indices. We conducted wet retroreflectivity test using the EN 1436 standard as the basis. We also conducted luminance tests for different glass bead refractive indices and line marking thicknesses. RESULTS : 1. Phosphorescent road line markings specimens satisfied the 「KS M 6080」standard. 2. In dry retroreflectivity test, phosphorescent road line markings sprayed with glass beads satisfied the national police agency standard (240 mcd/(m2₩Lux)). Wet retroreflectivity test results showed that except for one type of No.1 glass beads, phosphorescent road line markings specimens sprayed with glass beads of one type of No.3 and two types of No.1 satisfied the national police agency standard (100 mcd/(m2₩Lux)). 3. Phosphorescent road line markings had higher retroreflectivity than non-phosphorescent road line markings in the dry condition. 4. Phosphorescent road line markings sprayed with glass beads demonstrated improved luminance. Luminance increased with higher glass bead refractive index and with increased line marking thickness. However, when the thickness crossed a certain threshold, phosphorescence ceased to increase; this is a characteristic of the phosphorescence phenomenon. CONCLUSIONS : Visibility across short distances can be ensured when phosphorescent road line markings are sprayed with glass beads, because of the retroreflection phenomenon. It is also possible to ensure far visibility using phosphorescent road line markings.
        4,000원
        438.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A variety of methods for detecting the location of an underground water pipeline are being used across the world; the current main methods used in South Korea, however, have the problems of low precision and efficiency and the limitations in actual application. On this, this study developed locator capable of detecting the location of a water pipe by the use of an IMU sensor, and technology for using the extended karman filter to correct error in location detection and to plot the location on the coordinate system. This study carried out a tract test and a road test as basic experiments to measure the performance of the developed technology and equipment. As a result of the straight line, circular and ellipse track tests, the 1750 IMU sensor showed the average error of 0.08-0.11%; and thus it was found that the developed locator can detect a location precisely. As a result of the 859.6-m road test, it was found that the error was 0.31 m in case the moving rate of the sensor was 0.3-0.6 m/s; and thus it was judged that the equipment developed by this study can be applied to long-distance water pipes of over 1 km sufficiently. It is planned to evaluate its field applicability in the future through an actual pipe network pilot test, and it is expected that locator capable of detecting the location of a water pipe more precisely will be developed through research for the enhancement of accuracy in the algorithm of location detection.
        4,000원
        439.
        2016.06 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        기는 우주만물을 구성하는 본질로 눈으로 볼 수도 없고 손으로 만질 수 없는 아주 미세한 물질과 운동의 통일체다. 음양의 대립통일로 기의 승강운동이 생명조절 시스템인 장부에서 일어나며, 각 장 부 기의 승강운동의 협조 평형으로 우리가 정상적인 생명활동을 유지하고 있는 것이다. 배꼽호흡테 라피는 복식호흡법과 마사지로 누구나 손쉽게 할 수 있는 몸과 마음의 호흡마사지 치유프로그램으로 인체의 생체에너지(氣)순환의 촉진과 조절로 자연치유능력을 향상시켜준다. 오장육부에 질병이 생기 면 복부에서 그에 상응하는 단서를 찾을 수 있는데 바로 배의 주름과 그 주위의 응어리가 반응점이 다. 망진과 복진으로 반응점을 찾아 복식호흡과 마사지로 다스리면 자연스럽고 신기하게 배꼽주위가 부드러워져 질병이 치유되어 건강을 유지할 수 있다.
        4,000원
        440.
        2016.06 구독 인증기관 무료, 개인회원 유료
        본 연구는 금융이해력 수준을 단계별로 나누어 금융이해력 수준에 따라 다양한 금 융자산을 보유하는데 영향을 주는 지 살펴보고 각 금융자산을 보유하는 데 금융이 해력 단계별 수준이 어떠한 영향력을 미치는지 분석하고자 하였다. 이러한 분석을 위하여 한국금융투자자보호재단이 실시한 2014 펀드 투자자 조사(Fund Investor Survey)자료를 통해 서울 및 6대 광역시와 수도권 신도시에 거주하는 만 25세 이 상 64세 이하 일반인 2,530명을 분석대상으로 하였다. 그 결과 기초 금융이해력 수준이 심화 금융이해력 수준에 비해 높게 나타났고, 기초 금융이해력 수준보다 심 화 금융이해력 수준이 다양한 금융자산을 보유하는데 영향을 주었으며 금융자산의 유형에 띠라 금융이해력 수준의 영향력이 다르게 나타남을 알 수 있었다.
        6,000원