• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.119-126
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• 2012

Portland cement production-1.5billion tonnes yearly worldwide-contributes substantially to global atmospheric pollution(7% of total of $CO_2$ emissions). Attempts to increase the utilization of fly ash, by-products from thermal power plant to partially replace the cement in concrete are gathering momentum. But most of fly ash is currently dumped in landfills, thus creating a threat to the environment. Many researches on alkali-activated concrete that does not need the presence of cement as a binder have been carried out recently. Instead, the sources of material such as fly ash, that are rich in Silicon(Si) and Aluminium(Al), are activated by alkaline liquids to produce the binder. Hence concrete with no cement is effect reduction of $CO_2$ gas. In this study, we investigated the influence of the compressive strength of mortar on alkaline activator and curing condition in oder to develop cementless fly ash based alkali-activated concrete. In view of the results, we found out that it was possible for us to make alkali-activated mortar with 70MPa at the age of 28days by using alkaline activator manufactured as 1:1 the mass ratio of 9M NaOH and sodium silicate and applying the atmospheric curing after high temperature at $60^{\circ}C$ for 48hours.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.3
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• pp.102-109
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• 2011

In this study, in order to develop ultra rapid hardening mortar(URHM) for tunnel repairs using bottom ash of low recycle ratio and Admixture as Eco concept, watertightness and durability properties of URHM on temperature condition of construction field were performed. Test result, seepage quantity and water absorption coefficient regarding watertightness of URHM were as in the following : series II > series I. Seepage quantity for the standard condition were smaller than low temperatures. all specimens were satisfied below 20g as standards of seepage quantity on KS F 4042. Because of the decrease of unit cement content by to replacement of blast furnace slag, the neutrlization resistance for durability properties was reduced. The result of alkali resistance and acide resistance, compressive strengths for specimens soaked in calcium hydroxide solution of seriesI were lower than compressive strengths for specimens not soaked. On the other hand, the case of series II show that the deterioration of compressive strengths for specimens was not almost showed. Compressive strengths of specimens soaked were similar with specimens not soaked except series II-C in $5^{\circ}C$. Therefore, specimens using both blast furnace slag and bottom ash were good in alkali resistance and acide resistance.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.2
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• pp.389-395
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• 2017

A study was carried out to improve the field implementation of asphalt surface reinforcement method which is a preventive maintenance. Mean Texture Depth (MTD) was measured to quantify the surface condition and used to determine the optimum application rate. Determining the application rate using MTD can reduce the material loss from 30% to 15%. In order to reduce the curing time to 30 minutes, the heat capacity of $317kcal/m^2$ is required. Therefore, the design capacity of the heating curing device requires more than 380,000 kcal/hr. The asphalt surface reinforcement method is preferably applied at a time when slight cracking occurs before the permanent deformation becomes serious. Through the analysis of the pavement survey data, it was decided to apply the surface reinforcement method at the crack rate of 3~4%. Heating the surface reinforcement agent to $50^{\circ}C$ improves workability and ensures sufficient penetration depth even at a crack width of 1 mm. The results will be utilized as basic data for the development of automated construction equipment for efficiency improvement.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.2
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• pp.112-119
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• 2023

In this study, the variations in CO₂ uptake according to the type and amount of alkali-based activator (Ca(OH)₂, CSA) of geopolymer paste were evaluated. As the amount of activator added to the geopolymer paste increased, the fluidity of the paste is decreased and the compressive strength increased. According to the type of activator, it was confirmed that the addition of Ca(OH)₂ had a greater effect on improving the compressive strength than CSA. As a result of changes in chemical properties according to carbonation curing, the amount of C-S-H and C-A-S-H gels produced before carbonation increased as the amount of activator increased, and amount of CaCO₃ produced after carbonation increased. The reactivity of the blast furnace slag and zeolite increased due to the addition of the activator, and the reactivity tended to increase as the amount of addition increased. As a result of CO₂ uptake, 10.3 wt% when Ca(OH)₂ 10 % was added and 8.77 wt% when CSA 10 % was added was confirmed. It increased by 421 % and 388 % respectively, compared to the case where no activator was added.

• Journal of the Korean Geosynthetics Society
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• v.17 no.2
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• pp.41-49
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• 2018

The purpose of this study is to fabricate a full scale road embankment using lightweight air foamed soil as a soil material on soft ground and to investigate its material characteristics and behavior in order to promote dredged soil utilization and minimize ground improvement. As a result of the laboratory test of the onsite mixed samples, the total unit weight of the specimens decreased almost linearly until curing 28 days. In particular, the total unit weight after 28 days of curing was reduced to about 81% of the slurry state before curing, which will be useful in the formulation of similar native soil materials in the future. The unconfined compressive strength began to decrease with the 14th day of curing as shown in the previous study. When the cement content is increased, the strength decreases sharply at a small strain change after the occurrence of the maximum compressive strength, and the maximum strength is exhibited in a range of a smaller axial strain than normal range. The settlement at the surface layer of the ground due to the lightweight embankment was about 1 / 2.75 of the soil embankment and was in agreement with the unit weight ratio (1 / 2.7) of the embankment materials. This indicates the cause and effect of the settlement due to the difference in self weight of the embankments. Also, the difference in settlement between soil and lightweight embankment increased with increasing depth. This shows that the difference in the point at which the settlement is terminated is clear. The ground horizontal displacement under the lightweight embankment was about 15~20% smaller than that of the soil embankment and the depth of occurrence was also 4.5~5.0m shallower in the lightweight embankment.

• Journal of Korean Medical classics
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• v.21 no.4
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• pp.193-196
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• 2008

최근에 "내경(内经)"의 연구(研究)가 이론연구(理论研究)에 편중되어서 그 내용(内容)이 문자훈고(文字訓詁), 판본류전(版本流傳), 음양오행(陰陽五行), 장상학설(藏象學說), 체질학설(體質學說), 병인병기(病因病機), 병증방약(病證方藥), 치칙치법(治則治法), 양생(養生)의 많은 분야를 섭렵하고 있으나,각가학설(各家學說)의 측면에서 "내경(內經)"을 연구한 사람은 비교적 적다. "내경(內經)"은 한 사람의 손에서 나온 것이 아니며, 한 시대의 저작(著作)도 아니고, 상당한 시간 동안에 많은 의가(醫家)들의 경험(經驗)이 집결(集結)되어 편집됨으로써 각가학설(各家學說)의 성질(性質)을 띄고 있다. 비록 그렇다 하더라도 "내경(內經)"의 각편(各篇)의 경문(經文)에 종합된 이론 체계는 그 일치성이 있으나, 구체적인 관점에서 같지 않은 것이 적지 않은데, 몇 가지의 학술관점(學術觀點)은 모두 고대의가(古代醫家)들의 귀중한 경험(經驗)의 결정(結晶)으로서 옛날부터 중점적으로 연구(研究)하였다. 각가학설(各家學說)의 측면에서 "내경(內經)"을 연구하면 중의학(中醫學)이 후세(後世)에 발전(發展)한 중(中)에 약간의 내용상의 불일치를 설명하는데 유용하고,여러 학술이론과 각종 학술류파(學術流派)의 형성(形成), 발전(發展) 과정(過程)을 심도 있게 이해하는 할 수 있어서 이론과 임상의 측면에 많은 도움을 준다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.1
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• pp.419-424
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• 2012

This study is a research on the buckling analysis of a portable prestressing device using finite element analysis program, ABAQUS. In order to produce 50m-span PSC girders using pretensioning method, a portable prestressing device has to endure a large jacking force about 10MN. Therefore it shall be safe and stable about the jacking force. In this study, the buckling analysis technique is developed and the buckling analysis of a portable prestressing device is performed using previous studies about the analytical model that the validity of the analytical model was demonstrated by comparing analytical results with experimental results. The stability of the device to produce 10m span PSC girders is investigated.

• Journal of Korean Medical classics
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• v.28 no.2
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• pp.61-66
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• 2015

Objectives : Through the analyze of formative factor of time sense and the vital movement temporal rhythm in Huang Di Nei Jing(黃帝內經). Methods : We find out the principle and methods of Chronomedicine and Health Preserving in Huang Di Nei Jing(黃帝內經), and this finding will direct the life nurturing for later generations. We find that time sense had been established in Huang Di Nei Jing(黃帝內經), which had yin-yang and five elements characteristic. Results : There have temporal rhythm of functions of zang-fu viscera, meridian and collateral, qi and blood. Based on the theory of correspondence between human body and natural environment, established principle of health maintenance about based on yin and yang, temporal rhythm of visceral qi. Conclusions : Established health maintenance methods based on time such as adjusting-spirit according to time, regular daily life, dietary regimen according to time, needling and moxibustion according to time. These methods will guide syndrome differentiation and therapeutic method and Medication which based on suitable time.

• Journal of Korean Medical classics
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• v.21 no.4
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• pp.233-236
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• 2008

본 논문은 "주역(周易)" 원도(圓道)의 기본원리(基本原理)를 이용하여 임독맥(任督脈)이 순환(循環)하는 원도(圓道)의 특징을 논한 것이다. "건(乾)은 머리가 되고,곤(坤)은 배가 된다"는 것과 "사람 몸의 음양으로 말하면 등은 양(陽)이 되고 배는 음(陰)이 된다."는 규칙에 의하여,임맥(任脈)은 음효(陰爻)에 속하고 독맥(督脈)은 양효(陽爻)에 속한다고 보면 임독(任督) 이맥(二脈)이 건곤(乾坤) 이괘(二卦)와 같으니 십이경맥(十二經脈)의 부모(父母)가 된다고 볼 수 있다. 임독(任督) 이맥(二脈)이 서로 만나는 구조는 순환하고 포괄하며 폐쇄된 원도(圓道)의 형식을 이루고 있다. 위로 향하여 순환하는 것은 이미 임맥(任脈)은 오르고 독맥(督脈)은 내려가는 (정방향의) 영기(營氣)의 순환방식이 존재할 뿐만 아니라 또한 독맥(督脈)은 오르고 임맥(任脈)은 내려가는 (반대방향의) 원기(元氣)의 순환 방식도 존재하므로 정(正)과 반(反)이 서로 혼합(混合)된 태극의 양식을 구성하고 있다. 임독(任督)은 또한 생명(生命)이 기원(起源)하는 기초(基礎)이며 곡기(穀氣) 이도(二道)의 요로(要路)이며 기기(氣機) 승강(升降)의 동력(動力)이며 삼초명문(三焦命門)의 지도리이고, 생리(生理), 병리(病理)와 양생(養生), 치료(治療) 등에 있어서 모두 십이정경(十二正經)의 강령이 된다.

• Journal of Korean Medical classics
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• v.35 no.2
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• pp.77-98
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• 2022

Objectives : This paper intends to examine the essence of Joseon's cultivation techniques as written in the vast encyclopedia Imwon-gyeongje-ji. Methods : Items related to cultivation techniques in the Imwon-gyeongje-ji were brought together and analyzed through various cases that match the theme and structure of this paper, focusing on the relationship of Body-Environment-Society Results & Conclusions : Based on the contents of the Imwon-gyeongje-ji, it could be said that Seo Yu-gu consistently attempted to secure and improve health, well-being, and welfare in all levels of an individual's body, environment, and society while stating to have integrated Buddhist and Daoist methods based on Confucius cultivation. This thought is linked to the ideals of Zhongyong, one of the main scriptures of Confucianism, which could be summarized by the concept of the Heaven-Earth Cultivation. In specific, contents within the 16 treaties of the Imwon-gyeongje-ji such as the Boyang-ji, Inje-ji, Jeongjo-ji, Yewon-ji, Yiwun-ji, Yuye-ji, Yegyu-ji, etc., that could be categorized as personal, environmental and societal cultivation has great implications for people today in that it could lead us to an integrated path of cultivation through the inter-connection of body, environment, and society.