• 한국안전학회지
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• 제38권2호
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• pp.44-51
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• 2023

With the recent increase in gas energy use, risk management for explosion accidents has been emphasized. Protective walls can be used to reduce damage from explosions. The KOSHA GUIDE D-65-2018 suggests the minimum thickness and height of protective walls, minimum reinforcement diameter, and maximum spacing of reinforcements for the structural safety of the protective walls. However, no related evidence has been presented. In this study, the blast load carrying capacity of the protective wall was analyzed by the pressure-impulse diagrams while changing the yield strength of the reinforcement, concrete compressive strength, reinforcement ratio, protective wall height, and thickness, to check the adequacy of the KOSHA GUIDE. Results show that failure may occur even with design based on the criteria presented by KOSHA GUIDE. In order to achieve structural safety of protective walls, additional criteria for minimum reinforcement yield strength and maximum height of protective wall are suggested for inclusion in KOSHA GUIDE. Moreover, the existing value for minimum reinforcement ratio and the thickness of the protective wall should be increased.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 가을학술발표대회논문집
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• pp.275-276
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• 2023

This study introduces the current progress of study on the development of protective wall aimed at preventing the spread of ultra-fast fires and ensuring fire safety in industrial facilities.

• 한국군사과학기술학회지
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• 제12권5호
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• pp.571-576
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• 2009

In terms of protective engineering, there are no noticeable researches regarding covered-positions for smaller units in South Korea. So, standards to maintain and build protective facilities for larger units have been applied in ones for smaller units without any adjustment. The previous study was to calculate penetration depth of the concrete walls because the experiment performed indoor. In this outdoor experiment, velocity of projectile impact as one of the other important factors was considered to prove the validity of 30cm concrete wall thickness as effective protective level of the covered-position. Random effects and extraneous variables which could be occurred in outdoors experiment were controlled with statistical techniques. As a result, velocity of projectile impact was significant variable and the given standard, 30cm thickness of concrete walls was as valid as ever.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.434-437
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• 2005

Chemical Mechanical Polishing (CMP) has become an essential step in the overall semiconductor wafer fabrication technology. In general, CMP is a surface planarization method in which a silicon wafer is rotated against a polishing pad in the presence of slurry under pressure. The polishing pad, generally a polyurethane-based material, consists of polymeric foam cell walls, which aid in removal of the reaction products at the wafer interface. It has been found that the material removal rate of any polishing pad decreases due to the so-called 'pad glazing' after several wafer lots have been processed. Therefore, the pad restoration and conditioning has become essential in CMP processes to keep the urethane polishing pad at the proper friction coefficient and to allow effective slurry transport to the wafer surface. Diamond pad conditioner employs a single layer of brazed bonded diamond crystals. Due to the corrosive nature of the polishing slurry required in low pH metal CMP such as copper, it is essential to minimize the possibility of chemical interaction between very low pH slurry (pH <2) and the bond alloy. In this paper, we report an exceptional protective coated conditioner for in-situ pad conditioning in low pH Cu CMP process. The protective Cr-coated conditioner has been tested in slurry with pH levels as low as 1.5 without bond degradation.

• ALGAE
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• 제23권3호
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• pp.163-175
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• 2008

Phenolic compounds play a major role in the interaction of plants with their environment. They are thought to have been a feature of higher plants since early colonization of the land. Phenolics are crucial for many important aspects of plant life. They can play structural roles in different supporting or protective tissues, for example in cell walls, they can be involved in defence strategies, and signalling properties particularly in the interactions between plants and their environment. In brown algae, phenolic compounds are contained within membrane bound vesicles known as physodes, and their roles in algae are thought to be similar to those of higher plant phenolics. They can be stained using various histochemical stains, however, none of these stains are phenolic specific so care must be taken during interpretation of such results. Many, but not all phenolics are also autofluorescent under UV or violet light. Physodes are involved in cell wall construction, both in primary and secondary walls in brown algae. They bind together with other wall components to make a tough wall. They have also been found to play a role at fertilization, in blocking polyspermy in some species. Sperm are very quickly rendered immobile after phenolic release from newly fertilized zygotes seconds after fertilization. Phenolic compounds are thought to be important herbivore deterrents in some species due to their astringent nature. Phenolic compounds also offer effective UV protection in the early life stages and also the adults of many algal species. In the future, this factor may also make them an important player in the pharmaceutical and skincare industries.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.2258-2270
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• 2008

After rapid running is begun in domestic, problem by the train wind that was not considered at existent train running appeared. If the High-Speed railway business speed rises by 350km/h in the future, is going to become more big issue. This study conducts an experiment that measure in local about KTX train beside Gyeongbu High-Speed railway track about aerodynamics effect that happen by passage of train and analyzed. In case KTX II runs with the 350km/h speed, forecasted effect that get in the simple vertical surfaces parallel to tracks according to distance from rail center. Compared construction size with structural analysis in case do not consider with case that consider the train wind about soundproofing walls representatively. As a result, proposed wind load standard that apply at soundproofing walls design.

• International Journal of Internet, Broadcasting and Communication
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• 제12권3호
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• pp.74-86
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• 2020

This study discussesresearch and development of large-sized 3D printers that can be applied to construction and civil engineering for various designs of protective casing on foam liner for concrete exteriors. The consistent use of concrete represents the current surroundings. However, concrete exteriors in Korea have not considered the regional characteristics, but the concrete has been poured solely for economical aspects for the last decade or two. There are many cases of poor installation and not enough design development projects to correct it. This study was conducted to apply various patterns, regional characteristics, and 3D printing for protective casing design for foam liner to create various designs for the concrete walls. Therefore, we started researching on a large 3D printer, and designed and developed this system. Considering the chronological process, the properties of concrete structures were identified, the application of designs for concrete in Korea and abroad and the 3D printing materials for the protective casing were surveyed and analyzed, and a stereotype was produced in the first year to study designs for the beauty of concrete surfaces. In the second year, images of regional characteristics were gathered, design ideas for regional promotion were derived, virtual images were produced along with design modeling to simulate the appearances, and verify the effect of application and promotion. Finally, in the third year, the 3D printer for concrete foam liner was constantly improved to analyze the 3D printing program and the various library elements to complete an actual large-sized 3D printer.

• 건축역사연구
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• 제16권2호
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• pp.119-136
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• 2007

The purpose of this study is to examine the planning principles and historical meaning of Eupchi constructed during the Joseon Dynasty. I investigated the general character of Eupchi based on analyses of published materials from the Joseon Dynasty. The Joseon Dynasty, which started in 1392, set up Eupchi in a position to effectively govern the whole country. Eupchi was differentiated from the surrounding villages, and became the center of administration and education. Eupchi was established based on techniques taken from the capital. Following precedence in the capital, Eupchi was transformed with spaces for Confucian ceremonies. The cityscape of Eupchi was also differentiated from the surrounding villages. Such transformation of Eupchi represents the progress of urbanization. The developments found in Eupchi spread around Korea, and mark an important stage in the historical evolution of Korean urbanization. The Joseon Dynsasty used similar techniques from the capital to establish Eupchi. However, I found some differences between Eupchi and the capital. The Joseon Dynasty recognized that walls could protect not only the capital city bnt also the country from foreign enemies. Protective walls were required for a capital, but not for Eupchi. In addition, Eupchi did not have commercial institutions supported by the Dynasty. This further demonstrates that different planning principles were used at Eupchi.

• 보존과학회지
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• 제18권
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• pp.51-62
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• 2006

강진 무위사의 벽화보존각내에 보존된 벽화를 비파괴진단하기 위해 초음파탐사와 열적외선 조사를 실시하였다. 벽체의 진흙은 gravel 1.78 g, sand 5.39 g, silt 4.91 g, clay 6.26 g 이다. 조사된 8개 벽화의 초음파 속도 평균은 보살도(No.5)<관음보살도(No.5)<보살도(No.14)<주악비천도(No.20)<주악비천도(No.17)<오불도(No.3)<삼존도(No.1)<아미타내영도(No.2)로 순서이고 범위는 $71.63\sim3610.11m/s$, 평균 417.44m/s이며 일축압축강도 $70.34\sim533.28kg/cm^2$, 평균 $84.23kg/cm^2$이다. 신선한 진흙벽체의 초음파 속도는 약 850m/s를 내외하고 800 m/s이하의 속도가 나타나는 곳은 최초 발생한 미세균열이 확장되어 물성이 저하된 것으로 예상된다. 600 m/s내외에서는 한 화면에서 물성저하 또는 물성편차가 현저해 질 수 있다. 400m/s 내외의 속도는 진흙벽체가 서서히 압축되어 견고하게 느껴지나 물성은 취약하며 진흙벽체에 입상분해가 발생하기 쉬운 상태는 200 m/s이하의 속도를 나타내었다.

• 한국지열·수열에너지학회논문집
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• 제17권4호
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• pp.79-90
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• 2021

This paper presents a study to reduce the effect of blast pressure on the blast valves installed in protection tunnels, where the shape of the tunnel entrance and the blast pocket is optimized based on the predetermined basic shape of the protective tunnels. The reliability of the numerical tunnel models was examined by performing analyses of mesh convergence and overpressure stability and with comparison to the data in blast-load design charts in UFC 3-340-02 (DoD, 2008). An optimal mesh size and a stabilized distance of overpressure were proposed, and the numerical results were validated based on the UFC data. A parametric study to reduce the blast overpressures in tunnel was conducted using the validated numerical model. Analysis was performed applying 1) the entrance slope of 90, 75, 60, and 45 degrees, 2) two blast pockets with the depth 0.5, 1.0, and 1.5 times the tunnel width, 3) the three types of curved back walls of the blast pockets, and 4) two types of the upper and lower surfaces of the blast pockets to the reference tunnel model. An optimal solution by combining the analysis results of the tunnel entrance shape, the depth of the blast pockets, and the upper and lower parts of the blast pockets was provided in comparison to the reference tunnel model. The blast overpressures using the proposed tunnel shape have been reduced effectively.