• Journal of the Korea Concrete Institute
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• v.23 no.1
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• pp.99-107
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• 2011

This study is to performed to find the optimum mix proportion of the high strength and self compacting concrete for the above-ground LNG storage tank construction and field application. If LNG storage tank wall thicknesscan be reduced, the construction cost and quality can be improved by using self-compacting high strength concrete with compressive strength 60~80 MPa. For this purpose, low heat cement (Type IV) and class F fly ash are used in concrete mix to control hydration heat, flowability, and viscosity. Mix design variables of unit water, fly ash replacement ratio, water-binder ratio, and fine aggregate ratio are selected and tested for material properties and manufacturing cost of the concrete. Also, fly ash replacement ratio is considered using confined water ratio test. The test results showed that the optimum mix proportion of the self-compacting high strength concrete characteristics are as follows. 1) In case of the concrete with specified compressive strength of 60 MPa, the optimum mix proportion is fly ash replacement ratio of 20% and water- binder ratio of 27~30%. 2) In case of the concrete with the strength of 80 MPa, the optimum mix proportion is fly ash replacement ratio of 10% and water-binder ratio 25%. But unit water and fine aggregate ratio are 165 $kg/m^3$ and $51{\pm}2%$, respectively, regardless of the traget concrete compressive strength range. Also, test results showed that concrete manufacturing cost of 60 MPa and 80 MPa concrete require additional costs of 14~22% and 33%, respectively, compared to the manufacturing cost of 40 MPa concrete. Therefore, application of the self-compacting high strength concrete has proven to be economical in the perspective of the material cost, quality control, and site management.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.2
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• pp.99-107
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• 1998

This dissertationhas confirmed the non-flam mability of cast mold transformer that is increasingly used lately. As a research progress, the investigation has been performed on the installation status and each line of the subway system which have the most mold transformer accidents, and the impediment status of the transformer for rectifier and the high-voltage distribution transformer per each manufacturer. Then, a high voltage mold of the actual mold transformer has been installed in the horiwntal heating furnace and the heat has been applied by the standard heating temperature curve of KSF 2257(Fireproof testing meth od of the construction structures: 1993). Accordingly, the combustibility of the mold transformer based on the test results has been found that 78 minutes has been required for the complete burning per the KSF 2257 combustion test curve and that, after stopping the heat application of the horizontal furnace after ignition, the flame progress has not been made but shown as the self-extinguishing characteristics when the flame progress has been checked. Thus, the non-flammability and self-extinguishability of the mold transformer have been confirmed. The result of this dissertation has indicated that the accident involving mold transformer has been progressed and expanded by the dielectric breakdown or void due to the crack in the mold rather than a fire accident caused by a short-circuit or an overload.r an overload.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.8 no.1
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• pp.131-132
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• 1995

After studing of viewpoint of surgical disease in seven medical books related with Ju Dan Gye(朱丹溪) among four eminent physicians in the Jin and Yuan dynasties(金元四大家) I get conclsion as following. 1. Studied surgical diseases are total 40 kinds. 2. In 40 kinds surgical diseaes, case of having theory are 20 kinds, cases of having no theory and having only treatement by medicine are 20 kinds. 3. In therapy, cases that mainly use a method to eliminate pathogenic factors are 27 kinds; Acute mastitis(乳癰), Deep-seated mammary abscess(내巖), Acute appendicitis(陽癰), Bone cellulitis(附骨疽), Carbuncle of the lower abdomen near external genitalia(便毒), Leprosy(癩風), Macule(斑), Rash(疹), Urticaria(은疹), Scrofula(나역), Stagnant plegm(結核), Goiter andtumer(영유), Erysipelas(丹), Furuncle(정瘡), Scabies(疥瘡), Chancre(下疳瘡), Syphilitic skin disease(樣梅瘡), Incised wound (金瘡), Dermatopathy of lower limb and heel(脚足部瘡), Pemphigus(天疱瘡), Itching eruption due to blood-heat or wind heat(血風瘡), Dermatopathy of head(頭面瘡), Scald and burn(湯火瘡), Tetanus(破傷風) , Ecthyma(염瘡), Fistula(久漏瘡), Tinea(癬瘡), Cases that mainly use external therapy are 5 kinds; Rhagades of hand and foot(手足군裂), Vulvar ulceration(婦人陰瘡), Chilblain(凍瘡), Rabies(풍狗咬), Tinea capitis(白禿瘡), Cases that mainly use a reinforcing method are 4 kinds; Internal deep-rooted carbuncle(內疽), Pruritus and dryness of skin(皮膚乾燥), Anul fistula(漏瘡), Macule Caused by disorder of internal organ(內傷發斑), Cases that mainly use eliminating first and then reinforcing are 2 kinds; Pyogenic infection and ulcerous disease of slin( 疽瘡상癰疽瘡瘍), Lung abscess(肺癰), Case that mainly uses reinforcement and elimination in combination is only Haemorroid(痔瘡). Case divided into two groups that are reinforcing method and a method to eliminate pathogenic factor is only Trauma(打撲). Case that have no treatment by medicine is only Abscess of the scrotum(囊癰). 4. In 40 kinds surgical diseases, we can know that except a few important surgical diseases, Ju Dan Gye haven't distinguished viewpoint in many surgical diseases, because there are many cases that have no theory and have only simple treatment of medicine, and that mainly use a method to eliminate pathogenic factors and external therapy. 5. Representative theory of Ju Dan Gye, nourishing Yin and extinguishing fire(滋陰降火), has little effect on therapy of surgical disease. We need to try statistical division of internal and external remedy in the future, and by studing of surgical disase in medical books related with four eminent physicians in the Jin and Yuan dynasties, I think we can see their viewpoint of surgical disease.

• Clean Technology
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• v.25 no.1
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• pp.33-39
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• 2019

A.C (activated carbon) is mainly used to remove VOCs (volatile organic compounds), however, it has many problems such as fire risk due to increasing of adsorbent surface temperature during VOCs ad/desorption, increased cost by frequent replacement cycles requirement and performance degradation when containing moisture. In order to solve these problems, many researches, hydrophobic zeolite adsorbents, have been reported. In this study, $NH_4{^+}Y$-zeolite was synthesized with Y-zeolite through steam treatment and acid treatment, which is one of the hydrophobic modification methods, to secure high surface area, thermal stability and humidity resistance. The Y, Y-550-HN, Y-600-HN and Y-650-HN had adsorption capacities of $23mg\;g^{-1}$, $38mg\;g^{-1}$, $77mg\;g^{-1}$, $61mg\;g^{-1}$. The change of Si/Al ratio, which is an index to confirm the degree of modification, was confirmed by XRF (X-ray fluorescence spectrometer) analysis. As a result, the adsorbtion performance was improved when Y-zeolite modified, and the Si/Al ratio of Y, Y-550-HN, Y-600-HN, Y-650-HN were increased to 3.1765, 6.6706, 7.3079, and 7.4635, respectively. Whereas it was confirmed that structural crystallization due to high heat treatment temperature affected performance degradation. Therefore, there is an optimal heat treatment temperature of Y-zeolite, optimum modification condition study could be a substitute for activated carbon as a condition for producing an adsorbent having high durability and stability.

• Journal of Climate Change Research
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• v.4 no.4
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• pp.331-348
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• 2013

The frequency and intensity of abnormal climate caused by climate change is increasing in Korea. Also, the amount of damage from disaster is increasing rapidly. The research on vulnerability assessment analyzes environmentally, socially and economically vulnerable indicators and is ongoing to reduce the intensity of damage and establish adaptation policies for climate change. Therefore, in this study, we assessed vulnerability using weighting value derived by the regression equation. There are 3 evaluation items : vulnerability assessment for farmland erosion to flood, vulnerability assessment for health to heat wave, vulnerability assessment for forest fire to drought. For this study, indicators for each sectors were selected and spatial data for each sectors were established using GIS program. Results showed that vulnerability to heat wave was more affected by climate factors. On the other hand, vulnerability to flood and drought was more affected by social-economic factors. Then, to analysis efficiency of the regression analysis, vulnerability result was compared between the existing vulnerability research with no weighting applied and the vulnerability research with the influence of weighting value derived by the regression. This study showed that the regression analysis is efficient to provide practical and feasible alternatives in terms of planning climate change adaptation policies and it is expected to be utilized for vulnerability assessment in the future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.619-625
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• 2019

It is difficult to design because of the plug-holing phenomenon in which the amount of smoke discharged from the vertical vent is smaller than the designed amount of smoke. In this study, the effect of cross-sectional area ratio of tunnel and natural ventilation and heat release rate of fire source on plug-holing phenomenon occurring in natural ventilation system was experimentally analyzed. In the experiment model reduced to 1/20 size, the aspect ratio of the tunnel and the vertical vent was fixed, and the influence on the plug-holing phenomenon was confirmed by varying the sectional area ratio of the tunnel and the vertical vent. Experimental results show that the plug-holing phenomenon is caused by the comparison of the smoke boundary layer temperature with the temperature in the vertical vents, and the flow and temperature distribution characteristics under the vertical vents are changed as the cross-sectional area ratio of the tunnel and vertical vents increases. The plug-holing phenomenon is affected by the cross-sectional area ratio between the tunnel and the vertical ventilation. The greater the cross-sectional area ratio, the greater the probability of plug-holing.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.2
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• pp.61-70
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• 2019

Geopolymer is an eco-friendly construction material that has various advantages such as reduced $CO_2$ emission, fire resistance and low thermal conductivity compared to cement. However, it has not been many studies on the thermal behavior of the surface of the geopolymer panel when flame is applied to the surface. In this study, surface characteristics of hardened geopolymer on flame exposure was investigated to observe its characteristics as heat-resistant architectural materials. External structure changes and crack due to the heat shock were not observed during the exposure on flame. According to the residue of calcite and halo pattern of aluminosilicate gel, decarboxylation and dehydration were extremely limited to the surface and, therefore, it is thought that durability of hardened geopolymer was sustained. Gehlenite and calcium silicate portion was inversely proportional to quartz and calcite and significantly directly proportional to BFS replacement ratio. Microstructure changes due to the thermal shock caused decarboxylation and dehydration of crystallization and it was developed the pore and new crystalline phase like calcium silicate and gehlenite. It is thought that those crystalline phase worked as a densification and strengthening mechanism on geopolymer panel surface.

• Korean Journal of Materials Research
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• v.33 no.1
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• pp.15-20
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• 2023

'Tracers' are bullets that emit light at the backside so that the shooter can see the trajectory of their flight. These light-emitting bullets allow snipers to hit targets faster and more accurately. Conventional tracers are all combustion type which use the heat generated upon ignition. However, the conventional tracer has a fire risk at the impact site due to the residual flame and has a by-product that can contaminate the inside of the gun and lead to firearm failure. To resolve these problems, it is necessary to develop non-combustion-type tracers that can convert heat to luminance, so-called 'thermoluminescence (TL)'. Here, we highly improve the thermoluminescence properties of MgB₄O₇ through co-doping of Dy³⁺+Ce³⁺ and Dy³⁺+Na⁺. The presence of doping materials (Dy³⁺, Ce³⁺, Na⁺) was confirmed by XPS (X-ray photoelectron spectroscopy). The as-synthesized co-doped MgB₄O₇ was irradiated with a specific radiation dose and heated to 500 ℃under dark conditions. Different thermoluminescence characteristics were exhibited depending on the type or amounts of doping elements, and the highest luminance of 370 cd/m² was obtained when Dy 10 % and Na 5 % were co-doped.

• 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.

• Herbal Formula Science
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• v.16 no.1
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• pp.1-13
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• 2008

The Oriental Medical Literature Relating to Treatment of Gyogamdan in Ki Stagnation : focused on Suseunghwagang The normal drift of a current Ki can maintain a function of body. An abnormal drift of a current Ki which is called a Ki Stagnation by lots of thinking or agony gets to a various disease syndrome. A Ki Stagnation is similar to a mental stress disease. It is a common disease for us to contact easily, so, it is very valuable to study. Gyogamdan which is composed of Cyperi Rhizoma L. and Poria cum Radix pini has been used by basic prescription of a symptom related to all kinds of Ki disease, after being recorded to Hongssijibhumbang first. Gyogamdan has an ability to regulate Ki , through 'Suseunghwagang-centric'(Ascending the Water and Descending the Fire) in body. Gyogamdan compares to Gamijajoohwan which can treat eyes dizzy by ascending heat and Gongjindan which can regulate lack of basic Ki through 'Suseunghwagang-centric'. It is general for the herb and acupuncture to give medical treatment coming together in oriental medicine, so do Gyogamdan and Sagwan Acupoints. Gyogamdan in composition Cyperi Rhizoma L. and Poria cum Radix pini and Sagwan Acupoints in composition Hapkok and T'aech'ung get to synergistic effects. Therefore, a Ki Stagnation treatment through unions of Gyogamdan and Sagwan Acupoints may have more effects than when a treatment used each one alone. Be considered that we have to study Gyogamdan and Sagwan Acupoints carried out an experiment to set up the previous theory in future