• Tunnel and Underground Space
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• v.33 no.1
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• pp.29-41
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• 2023

The brittleness of rocks plays an important role in determining the fragmentation and failure behavior of rock. However, there is still no standard method to evaluate the brittleness of rock, and previous studies have suggested the several definitions for estimation of brittleness of rock. Even in the process of mechanical rock excavation and drilling, the brittleness of rock is considered as an important property for evaluating the excavation efficiency of mechanical excavators or boreability of rock. The previous studies have been carried out to investigate the correlation between different brittleness of rock and cutting efficiency and boreability of rock. This study introduced a method for calculating the brittleness of rock from punch penetration test, and analyzed the correlation between the brittleness of rock calculated by the uniaxial compressive and Brazilian tensile strengths and that from punch penetration test. From the results of correlation analysis, the relationship between various brittleness was confirmed, and it was found that PSI and BI₃ showed a good correlation with the strength-based brittleness index. In addition, the results indicated that B₃ and B₄ are suitable to represent the brittleness of rock in the field of mechanical rock excavation.

• Journal of the Korean Magnetics Society
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• v.5 no.2
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• pp.128-133
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• 1995

Yttrium Iron Garnet($Y_{3}Fe_{5)O_{12}$) films have been succsssfully grown on(111)GGG wafer by KrF excimer laser ablation of stoichiometric garnet target at the oxygen partial pressure, $P(O_{2}$, ranging 20 to 500 mTorr. During the deposition of the films the substrate temperature was maintained at $700^{\circ}C$ and the laser beam energy density at $7.75\;J/cm_{2}$. Microstructure, composition and magnetic properties of the films obtained were investigated as a function of oxygen pressure and thickness of the films. Epitaxial films with a dense and a smooth surface were reproducible at a low oxygen pressure. The films of $2.75\;{\mu}$ min thickness deposited at 20 mTorr of $P(O_{2})$ showed $4{\pi}M_{s}$ of 1500 Gauss and $H_{c}$ of 3 Oe after annealing at $800\;^{\circ}C$ for 20 minutes. As-deposited films of $0.8\;\mu\textrm{m}$ in thickness exhibited the $4{\pi}M_{s}$ of 1730 Gauss and $H_{c}$ of 7 Oe. The magnetic properties of the films obtained were almost identical to those of a single crystal YIG.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2023.04a
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• pp.49-49
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• 2023

본 실험은 콤부차의 발효시 에너지원으로 첨가되는 당(sucrose) 대신 꾸지뽕(Cudrania tricuspidata Bureau; silkworm thorn) 과일 발효액을 첨가하여 꾸지뽕-콤부차의 기능성을 구명하고자 하였다. 대조구인 콤부차는 끓여서 식힌 물 900mL에 홍차 2.4g을 넣어 한시간 동안 추출한 후 초기당도가 10°Bx가 되도록 sucrose를 첨가하였고, 처리구는 sucrose대신 꾸지뽕 과일 무게 대 sucrose의 비율을 1 대 0.9의 비율로 조제하여 발효시킨 꾸지뽕 발효액(당도 50°Bx)을 10°Bx가 되도록 희석하여 첨가하였다. 여기에 발효균인 SCOBY를 첨가한 후 실온에 3주간 보관하면서 1주일 간격으로 시료를 채취하여 총폴리페놀성 화합물 및 카테킨류 함량, 항산화 활성 및 인체 정상 폐세포주인 MRC-5와 폐암세포주인 A549의 세포 증식에 미치는 영향을 구명하였다. 발효 3주 동안 채취한 꾸지뽕-콤부차를 MRC-5 세포에 처리하였을 때 발효 2주까지는 꾸지뽕-콤부차가 대조구에 비해 약 10~30% 세포 증식효과를 보였고 발표 3주째에는 유사한 증식효과를 보였다. 폐암세포주 A549에 처리시에는 발효 2주째 대조구에 비해 낮은 증식율을 보였으나 그 차이는 크지 않았다. 이 결과는 꾸지뽕-콤부차가 인체 폐세포 증식을 촉진하나 폐암세포의 증식을 크게 억제하지는 않음을 의미한다. 총폴리페놀성화합물 함량은 대조구의 경우 발효기간이 경과함에 따라 증가하는 반면 꾸지뽕-콤부차는 조제직후 대조구에 비해 유의적으로 높은 함량을 보이다 서서히 감소하였는데 발효 2주째 대조구와 유사한 수준에 도달하였으며 3주째에는 대조구에 비해 낮은 함량을 보였다. 카테킨류(Epigallocatechin, Epigallocatechin gallate, 그리고 Epicatechin gallate, epicatechin)는 총 페놀성화합물과는 반대의 경향을 보였는데, 발표 2주까지는 꾸지뽕-콤부차의 함량이 유의적으로 높았다가 발표 3주째 크게 낮아졌다. 활성산소 제거능은 발효 2주째까지는 대조구에 비해 낮았으나 3주째 유의적으로 높아져 꾸지뽕-콤부차의 항산화활성은 카테킨류 함량에 비례함을 알 수 있었다. 기능성분 함량과 MRC-5 증식에 관한 상관분석시 총풀리페놀함량이 세포증식에 정의 상관관계를 나타내었다.

• Korean Journal of Construction Engineering and Management
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• v.25 no.1
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• pp.50-61
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• 2024

The market for compact houses is growing due to the demand for floor plans prioritizing user needs. However, clients often have difficulty communicating their spatial requirements to professionals including architects because they lack the means to provide evidence, such as spatial configurations or cost estimates. This research aims to create a framework that can translate sketched data-driven spatial requirements into 3D building components in BIM models to facilitate spatial understanding and provide building performance analysis to aid in budgeting in the early design phase. The research process includes developing a process model, implementing, and validating the framework. The process model describes the data flow within the framework and identifies the required functionality. Implementation involves creating systems and user interfaces to integrate various systems. The validation verifies that the framework can automatically convert sketched space requirements into walls, floors, and roofs in a BIM model. The framework can also automatically calculate material and energy costs based on the BIM model. The developed frame enables clients to efficiently create 3D building components based on the sketched data and facilitates users to understand the space and analyze the building performance through the created BIM models.

• Journal of Radiation Protection and Research
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• v.30 no.1
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• pp.1-7
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• 2005

Radiation absorption parameters of carbon fiber panel were measured in comparison to acrylic panel. $30{\times}30cm$ sized 2mm thick carbon fiber panel and identical sized 6mm thick acrylic panel were placed in tray holder position and 0cm, 5cm, 10cm from surface of phantom. Radiation field size was $10{\times}10cm$. 50MU of 4MV photon was irradiated to the phantom with dose rate of 300MU/min. Source-to-phantom distance was 120cm. Radiation dose was measured with 0.6cc Farmer-type ionization chamber with 1cm build-up. Measurement was repeated thrice and normalization was done to the dose of the open field. Radiation transmission rate of carbon fiber panel is approximately 1% lower than acrylic panel of equivalent thickness. However, considering the strength of the material, transmission rate is higher for carbon fiber panel. Although carbon fiber panel increases the radiation dose when attached to the surface for about 2%, it normalizes the radiation dose to 97-99% of irradiated dose which could have been lowered to as much as 5-7.5% with acrylic panel. As carbon fiber panel is stronger than acrylic panel, radiation fixation device could be made thinner and thus lighter and furthermore, with increased radiation transmission. This in turn makes carbon fiber more ideal material for radiation fixation device over conventionally used acrylic.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.517-520
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• 2008

Wireless sensor network supporting healthcare environment should provide customized service in accordance with context information such as continuous location change and status information for people or movable object. In addition, we should consider data transmission guarantees a person's bio information and privacy security provided through sensor network. In this paper analyzes LEACH protocol which guarantees the dynamic self-configuration, energy efficiency through configuration of inter-node hierarchical cluster between nodes and key distribution protocol used for security for data transmission between nodes. Based on this analysis result, we suggested self-configuration routing protocol supporting node mobility which is weakness of the existing LEACH protocol and data transmission method by applying key-pool pre-distribution method whose memory consumption is low, cluster unit public key method to sensor node.

• Journal of the Korean Society of Radiology
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• v.8 no.6
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• pp.347-355
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• 2014

Traditionally heating method, pasteurization, irradiation fumigation method and radiation sterilization through a variety of methods to be performed. Irradiation energy requirements compared to the other sterilization methods is small and a strong permeability as a continuous process is possible. Irradiation energy requirements compared to the other sterilization methods is small and a strong permeability as a continuous process is possible. Also sterile, conflict, and control the germination inhibition effective food safety in the food chain has been highlighted as a conservation technique. Foreign countries is carried out extensive research on the safety and the use of irradiation food, gradually increasing. As a result, awareness of the food is irradiated with a low average showed 2.73 point. Therefore through a variety of media to improve the awareness of irradiated food and the active promotion seems to require an appropriate educational program.

• Korean Chemical Engineering Research
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• v.45 no.2
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• pp.197-202
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• 2007

This research was basically carried out to extend the application of $CO_2$ absorption processes for flue-gas system, which are mainly applied to a reforming process in petro-chemical industries. In general, MEA absorbent has some problems in flue-gas treatment, such as, degradation, regeneration energy and absorption capacities. As we known, sterical hindered amine, typically AMP (2-amino 2-methyl 1-propanol), have a good potential to improve these problems. In this paper, the characteristics of $CO_2$ absorption in aqueous AMP solution were measured and compared with that of MEA. It has been found that the $CO_2$ absorption capacity in AMP is double than that of MEA in the low $CO_2$ partial pressure system such as flue-gas. Also, the equilibriums of $CO_2$-AMP system were partially suggested, which are essentially needed to design the absorption process.

• Applied Chemistry for Engineering
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• v.21 no.1
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• pp.58-62
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• 2010

CNT-$TiO_{2}$ nano complexes were prepared from $TiOSO_4$ and multi-walled carbon nanotube (MWCNT) by hydrolysis. The CNTs were dispersed uniformly with anatase $TiO_{2}$ in the prepared $TiO_{2}$-CNT complexes. The increasing MWCNT ratio leads to increased crystalline carbon and O/Ti ratio. The decomposition degree of methylene blue was experienced according to UV radiation time for study adsorption and photocatalytic activity. The samples having high MWCNT ratio show high adsorption and photodegradation. The high specific surface area, functional group having oxygen, low band gap energy, high electric conductivity, high volume to surface ratio, uniform structure and properties of MWCNT assist photocatalytic activity of CNT-$TiO_{2}$ complex.

• Journal of the Korean Society of Safety
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• v.22 no.4
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• pp.110-116
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• 2007

There have been 3E problems of energy, economy and environment since the earth has its history. Especially, as the industrial society is highly developing, human need in daily life has also changed drastically. With the introduction of 40 hour working week system, more households enjoy picnics on weekends. More gas accidents take place on Saturdays and on Sundays than any other days of week. Consequently, this study tries to find out the influence of flame caused by the explosion of butane canister on the adjacent combustibles and people by simulating relevant quantity of TNT. In addition, the damage estimation was conducted by using API regulations. If the scale of the radiation heat is known by calculating the distance of flame influence from the explosion site, the damage from the site can be easily estimated. And the accident damage was estimated by applying the influence on the adjacent structures and people into the PROBIT model. According to the pro bit analyze, the spot which is 50cm away from the flame has 97% of the damage probability by the first-degree burn, 8% of the damage probability by the second-degree burn and 4% of the death probability by the fire.