• 한국농공학회:학술대회논문집
• /
• 한국농공학회 2002년도 학술발표회 발표논문집
• /
• pp.153-156
• /
• 2002

The purpose of this research was to evaluate on the properties of fresh and hardened high-performance concrete(HPC) incorporating high-reactivity metakaolin(HRM). Setting time, heat of hydration, compressive strength, resistance to chloride-ion penetration, and repeated freezing and thawing test were carried out in order to investigate the properties of fresh and hardened state concrete. The properties of the HRM concrete were also compared with those of the portland cement concrete and silica fume(SF) concrete. The laboratory test results indicate that HRM material can be used as a supplementary cementitious material to produce high-performance concrete.

• 한국과학교육학회지
• /
• 제10권1호
• /
• pp.33-45
• /
• 1990

To achieve the aim of science education, it is known that warious teaching, and learning materials should have to be used. As a sub-textbook for primary science education, 'Sil Hum-Kwan Chal (Experiment and Observation), teaching and learing material are developed and using now in science. This material have following characteristics; (a) Soruce-book contains reading materials for additional information, various pictures to enririch the science concepts, and supplementary and enrichment activities. (b) Work-book consists of the detailed procedures of activities of experiments presented in the textbook, student can record the experimental procedures and results. (c) Operational manuals provide operation techniques for experimental equipments which are used in science class. In this study the using status are surveyed for the 3rd grade of primary school, and based on this survey the improvement plan are discussed in view of design, quantity and utility, of sub-textbook.

• Corrosion Science and Technology
• /
• 제6권1호
• /
• pp.12-17
• /
• 2007

Portland cement incorporating supplementary cementing material develops excellent mechanical properties and long term durability characteristics. India is a leading rice producing country and rice husk is considered as waste in the rice milling industries. In this present work, the rice husk ash (RHA) was added to concrete as cement replacement from 0 to 30%. Corrosion performance of reinforcing steel embedded in RHA blended concretes was studied using linear polarization, AC impedance and gravimetric methods. The corrosion rate of steel bars embedded in RHA concretes were compared with control concrete. The results clearly indicate that the corrosion rate of reinforcing steel embedded in concrete is significantly reduced with the incorporation of RHA. A good correlation among gravimetric method and electrochemical methods was observed. Electrochemical impedance study showed 98 percentage reduction in corrosion rate to the RHA blended concrete with 15% replacement than control concrete.

• 한국국방경영분석학회지
• /
• 제18권1호
• /
• pp.1-14
• /
• 1992

As North Korea signed 'the Korea Peninsula Non-Nuclearization Joint Declaration' at the end of last year as well as full-scope safeguards agreement with the IAEA in Jan.30 1992, her nuclear activity was incorporated into the international monitoring system and opportunities were arranged to .obstruct her nuclear weapon development and nuclear material diversion, which have been international issues up to recent years. However, achieving goals of the Joint Declaration and safeguards agreement should presuppose North Korea's sincerity toward the abandonment of nuclear weapon development. In this study, first of all, her nuclear policy, current situation of nuclear development and the capability of nuclear development are analyzed. Also, based on the analysis. attempts have been made to find methods of effective performance of the South-North Korea mutual nuclear inspection and the suggested methods are as follows; 1) Analysis of the limits of IAEA inspection and suggestion of its supplementary strategies 2) Securing and training professional inspectors for the South-North mutual inspection 3) Establishment of the verification technology to detect nuclear material diversion.

• 한국소음진동공학회논문집
• /
• 제13권6호
• /
• pp.415-422
• /
• 2003

In an apartment buildings, the floor Impact sound from upstairs has been regarded as a main source of noise causing discontentment among occupants. To set the optimum design for sound insulation, it is necessary to suggest the useful tools or technique that predict the floor impact sound. The purpose of this study is to suggest the supplementary formula(equation) and constant k considering vibration transmissibility in order to predict more precisely heavy floor impact sound by Impedance Method that have been briskly studied in Japan from comparing the measured values with the predicted values. The analyzed results had showed that if the damping material was glass wool or rubber, k=5 was proper and if the damping material was polystyrene foam, k>5 was desirable.

• Nuclear Engineering and Technology
• /
• 제54권12호
• /
• pp.4393-4411
• /
• 2022

In recent years, beryllium oxide has been widely utilized in multiple compact nuclear reactors as the neutron moderator, the neutron reflector or the matrix material with dispersed nuclear fuels due to its prominent properties. In the past 70 years, beryllium oxide has been studied extensively, but rarely been systematically organized. This article provides a systematic review of the application history, thermal properties, mechanical properties, corrosion behavior and fabrication methods of beryllium oxide. Data from previous literature are extracted and sorted out, and all of these original data are attached as the supplementary material, so that subsequent researchers can utilize this paper as a database for beryllium oxide research in reactor design or simulation analysis, etc. In addition, this review article also attempts to point out the insufficiency of research on beryllium oxide, and the possible key research areas about beryllium oxide in the future.

• 한국항공운항학회지
• /
• 제13권1호
• /
• pp.43-49
• /
• 2005

There are several ways to mold the complex material, and it is divided to vacuum pack mold, compression mold, and hand lay up for a high molecular substance as a basic material. Moreover, it can be divided to general manufacturing (Single form) and mold manufacturing(Mold form) under normal temperature for Firefly. Firefly was manufactured with hand lay up and general manufacturing that using the foam core, glass fabric, and template without mold. However, mold manufacturing that is producing the surface by semi-sandwich using thin foam core and glass fabric then reinforce the inside with spar and rib is on developing. Mold manufacturing can make easy to production, standardize the quality, and possible to mass producing. In this paper, we present the mold producing process for canard aircraft "Firefly", and the problems and solutions during producing Firefly. Moreover, it complements the defect that the problems caused by master manufacturing error when produce several masters of a large part, and make the manufacturing process to be shortened by the replacement from the supplementary plate to the foam that is installed when producing lay up mold.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
• /
• pp.773-777
• /
• 2002

In this study, we analyzed the LPG and LNG sensitivity measurement and voltage variation using catalytic type gas sensor characteristics in catalytic combustion type gas detecter sensors. gas detector shall operate as intended when exposed for 24 hours to air having a relative humidity of 0~85 percent at a temperature of $20[{\mu}m]$ and humidity of 45 percent at a temperature of $-10{\sim}40[^{\circ}C]$ the gas detecter sensors are to be subjected to operation for 210 days in an area that has been detemined to be equivalent to a typical residential atmosphere with an air velocity of 50 [cm/sec]. The source of energy for a gas detector sensors employing a supplementary basic circuit is energized from a separate source of supply direct applied voltage 2.1[V], 2.2[V], 2.3[V]. As a result, it was confirmed that the relative humidity and temperature by regression each analysis, compared to the LPG characteristic graph and methane characteristics graph by a relative humidity of 0 ~ 85 [%] at a temperature range of $-10{\sim}40[^{\circ}C]$ show a similar linear pattern on the whore.

• 복식문화연구
• /
• 제27권6호
• /
• pp.599-614
• /
• 2019

The aim of this study to provide basic reference data for the development of video contents used in pattern drafting education and to explore the possibility of utilizing YouTube videos in such education. Subject videos were selected using the number of views. A total of 596 videos and 28 channels were analyzed for the period July to September 2019 and the results are as follows. With regard to content, there were 27 pattern drafting items, the majority being dress, pants, skirt, blouse and sleeve drafting, although high-level content such as cowl, bustier, corset patterns were also available. Therefore, there is a high likelihood that YouTube videos could be used as educational material, especially as supplementary references to provide specific examples and easy explanations for difficult concepts or method, for students majoring in this field. However, as most videos currently focus on a few items, expanding video content to features a wider variety of clothing items at different levels is necessary. With regard to video length, it mostly ranged from 10 to 15 minutes. It is not advisable to create lengthy lecture-style videos expounding on different principles or variations in pattern drafting when developing educational video material.

• 콘크리트학회논문집
• /
• 제14권3호
• /
• pp.349-356
• /
• 2002

본 연구는 고반응성 메타카올린(HRM)을 혼입한 고성능 콘크리트(HPC)의 굳지 않은 콘크리트와 경화된 콘크리트의 특성을 평가하기 위해 수행되었다. 굳지 않은 콘크리트에 대해서는 공기량과 슬럼프 플로우, 응결시간 및 수화열 측정 시험을 실시하였다. 경화된 콘크리트에 대해서는 압축강도 및 염화물 투수시험, 마모저항성, 동결ㆍ응해 저항성 시험을 하였다. HRM 콘크리트의 특성은 또한 보통 포틀랜드 시멘트 콘크리트와 실리카 흄 콘크리트와 비교하여 나타내었다. 실험 결과 HRM 재료가 고성능 콘크리트를 생산하기 위한 시멘트 대체 재료로서 사용할 수 있음을 보여주었다.