• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.1
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• pp.74-80
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• 2009

This study analysis the fundamental properties of temperature-dependence corresponding the change of curing temperature classified by the replacement ratio of BS, and the results are summarized as following. As the properties of flow, plain satisfied with the target slump, and as the replacement ratio of BS increased, the flow increased, but the air content slightly decreased. The time of set delayed as the replacement ratio of BS increased, but the curing temperature $35^{\circ}C$, even with 80% BS replaced concrete, the time of set was faster than $5^{\circ}C$, $20^{\circ}C$ plain, so the temperature-dependence was much greater. The compressive strength was decreased as the replacement ratio of BS increased, especially as the curing temperature lower, the compressive strength was lower comparatively. Also as the age increased, the plain developed more strength, therefore it show the temperature-dependence is much larger.

• The Korean Journal of Archival Studies
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• no.5
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• pp.3-37
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• 2002

Today the market of EDMS is esteemed more than 100 billions won. It signifies a comming of age of electronic records. The traditional archival theories which are based on the paper records are confronted with a new challenge. In some leading countries of archival studies reorientation of archives management has been tried by a number of distinguished specialists such as Bearman and Hedstrom since 10 years. As a consequence new paradigm of archival theories has been developed. Also in Korea this new paradigm has been introduced by some expert such as Lee, Sang-Min, Sul, Moon-won, Lee, Seung-Eok. However their arguments are too general to offer a concrete clue for new paradigm. Faced by new age of electronic records, it's important to start a discussion for the reasonable methods of electronic records management at once. The most drastically changed part of record management by the electronic technique is the life-cycle of records. The commonly practiced three-stage life-cycle is to be reduced to the two-stage life-cycle, and the concept of the spatial movement of records is to be changed. It can be also pointed that the public emerges as user from the early creating stage of records beyond time and space. Thus is can be said that the method of the management features dynamic and cohesive. The method of appraisal must be also changed and reproduced, so that it can reflect the various levels considering dynamics of the electronic records. Supposedly it will be a core factor that causes the change of methodology in records management with the change of life-cycle theory. It must be noted that various subjects would be involved in the work of classification and description over time and space and that feedback between them is of important. Description also tends to be made at the crating stage of records and structured dynamically. It results from the change of life-cycle and the introduction of the concept of continuum. Such trend allows us to start discussions on the assumption that description of both creator and archival professionals act together an important role. Of course, it is linked with the methodology in which most descriptions are made automatically at the early drafting stage of the structure. The meat date is formed on the assumption that there should be feedback between areas of automatic description, description of creators and archival professionals. The most important thing in description is to develop a suitable way how it is structured. An alternative must be offered for managing data set. As iweb that is being operated by Myongji university shows, records created in daily business are managed not as electronic records but as date base. This is because they exist outside the repository in the EDMS system. Since data set often has various sources, an alternative for classification needs to be developed. It is now likely that database is filed according to the created year to be transferred automatically to the repository. Over a long-term the total management of database, electronic records and electronic information will be a topic. A right direction of new paradigm will be found for both iweb and E-government, when practice and studies of theories are combined and interacted.

• 한국노년학
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• v.29 no.2
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• pp.529-546
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• 2009

Depression in old age not only is prevalent but also causes a considerable amount of burden in physical, psychosocial, and economic terms. Intervention, however, is often delayed due to the understanding that considers depressive symptoms as a normal process of aging or signs of physical illnesses. Since the recognition of symptoms often initiate one's help seeking process, a correct identification of symptoms can contribute to early detection and intervention to depression in oneself as well as in others. This study interviewed 104 older adults living in an urban area, and explored their ability to correctly identify depressive symptoms and factors related to identification. The study results show that respondents who were able to correctly identify symptoms of depression were only 14%, and the rest defined the symptoms as social, economic, and other psychological issues. Of the factors in the logistic regression model, age being 75 and over and mass media as source of mental health information affected negatively their ability to correctly identify symptoms; mental health education programs affected positively their ability. Based on these results, it is suggested that such strategies as employing a face-to-face provision of concrete information and counseling can be more effective than delivering information via large-scale lectures. Additionally, a future research deems necessary to conduct an in-depth examination of mental health/illness-related contents on mass media.

• Journal of the Korea Concrete Institute
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• v.16 no.6 s.84
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• pp.805-811
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• 2004

In this paper, effects of mixture proportion and material condition on both fundamental properties, drying and autogenous shrinkage of high performance concrete are discussed. According to the results, for the effect of mixture proportion on the fundamental properties, decrease in W/B and unit water content results in reduction of fluidity, while air content has no variation. Compressive strength exhibits an decreasing tendency with an increase in W/B and unit water content do not remarkable affect the compressive strength. For the effect of materials on the fluidity, the fluidity of low heat portland cement(LPC) is smaller than that of ordinary portland cement(OPC). The use of Polycarbonic acid based superplasticizer(PS) has more favorable effect on enhancing fluidity than Naphtalene based superplasticlzer(NS) and Melamine based superplasticizer(MS). Air content of concrete using LPC is larger than that using OPC. The effects of superplasticizer type on the air content is larger in order of MS, PS and NS. The use of LPC exhibited lower strength development at early age than OPC, whereas after 91days, similar level of compressive strength is achieved regardless of cement type. Compressive strength of concrete is not affected by SP type. For the effect of mixture proportion and materials on drying and autogenous shrinkage, an increase in W/B results in reduction of drying shrinkage and an decrease in water content leads to reduce drying shrinkage. Autogenous shrinkage is not observed until 49 days with the concrete mixture with $35\%$ of W/B and $145 kg/m^3$ of water content. This is due to the combination effects of expansion admixture and shrinkage reducing admixture, which causes an offset of autogenous shrinkage. The use of LPC results in a reduction in autogenous shrinkage compared with OPC. SP type has little influence on the autogenous shrinkage. It is found from the results that mixture proportioning of high performance concrete incorporating fly ash, silica fume, expansion admixture and shrinkage reducing admixture is need to focus on the increase in W/B and the reduction in water content and the use of LPC and MS is also required to use to secure the stability against shrinkage properties.

• Korean Journal of Agricultural Science
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• v.16 no.2
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• pp.212-224
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• 1989

This paper reports results of an investigation to determine properties of superplasticizered fly ash concrete. The mixture proportions of fly ash were 0, 10, 20 and 30%, by weight of cement, and superplasticizer was added as a percentage of fly ash, 0, 0.6, 12 and 1.8%. To investigate the effective use of the superplasticized fly ash concrete, the basic data were analyzed. The results obtained were summarized as follows : 1. The unit water content was decreased by 1%, 6% and increased by 2% to the ratio of addition of fly ash 10%, 20%, 30%, respectively, but in case of the superplasticized fly ash concrete, it was decreased by 3~16%, 4~14% and 10~17%, at 0.6, 12, and 1.8% dosage of superplasticizer, respectively. 2. In the properties of the fresh fly ash concrete, the slump loss was reduced with the ratio of replacement of fly ash increased, and with times went by. When using superplasticizer in fly ash substituting concrete, the fludity in the concrete was not decreased. 3. The compressive strength of fly ash concrete at early ages was lower than that of ordinary concrete. At the later age of 28 days, the compressive strength with 20% addition of fly ash was increased than that of ordinary concrete. In cased of 10%, 30% addition of fly ash, the compressive strength were reduced. From this, it was proved that the optimum amount of fly ash appears to be about 20%. The compressive strength at all ages of superplasticized fly ash concrete was significantly higher than that of fly ash concrete, with increasing fly ash content. 4. In case of the tensile strength, the effects of the increasing strength with the ages were similar to those of the compressive strtength, and at the later ages was seen a decreasing tendency of strengths. 5. The correlation between compressive and tensile strength of superplasticized fly ash concrete was highly significant. The multiple regression equations of compressive and tensile strength were obtained on a function of the mixture proportion of fly ash and the addition of superplasticizer. The relation between compressive and tensile strength is higher than for ordinary concrete. The strength ratio is 7~11, and it is higher than that of ordinary concrete, 8~10. 6. Bulk density was decreased by 1~3% compared with ordinary concrete with the mixture proportion of fly ash increased, 10~30%, and decreased by 1~2% with the superplasticizer added 0.6~1.8%.

• Cartoon and Animation Studies
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• s.39
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• pp.451-472
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• 2015

Lian Huan Hua(連環畵) has occurred in the history of China Cartoon was initially developed as a unique literary style of Chinese painting and narrative combined. Also Lian Huan Hua are also tend to form once the fusion 1920s was also a very creative fashion cartoon style. This is also referred to as chain cartoon. In 1950-1960, China 's Lian Huan Hua also mature a 'golden age' legal group reaches to indicate the unique formal features developed independently. This work is a dramatic expression of Lian Huan Hua narrative, shows a more realistic representation techniques and art forms such as portraiture is a very big breakthrough was achieved artistic maturity of the work increased significantly. by He You Zhi(賀友直) and by Hau San Chuan(華三川) is a masterpiece of artistry and maturity in the period leading side. Chapter 2 looked at the origin and development of Chinese Lian Huan Hua, it was seen by the fact that China achieved new progress in Lian Huan Hua upset every time the combination of content and form, In addition, the work of 1950-1960 in the development process of China's Lian Huan Hua confirmed the fact that they won the biggest achievement in artistry and maturity surface. Therefore, Chapter 3 how 'golden age' masterpiece of and the dramatic narrative of expression by analyzing a specific angle in the multifaceted image of the , realistic portraiture, such as the acquisition of Chinese concrete artistry Lian Huan Hua I want to show. Analysis of the figures depicting nature, landscape screens. consisted of highlights and background and techniques of utilization, production methods. The purpose of this research work is to identify two conditions of great Lian Huan Hua through analysis of concrete work and painting techniques such as framing and directing the Lian Huan Hua's artistic achievements is to investigate the influence of China in the early comics. These two works are focused on a realistic view of life and put out was to create a more effective representation of information it attempts to pass a new production techniques and will have the significance. Also completed was a new style absorbed throughout the aesthetic advantages are compelling own personality writers of Eastern and Western paintings are remarkable in that its performance. But the difference in the two works represent all types and painting techniques has a the mood of common China's lives.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.1
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• pp.33-40
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• 2013

The cement industry brought very severe environment problems with massive carbon dioxide during its production. To solve this problem, attempts on Alkali-Activated Slag (AAS) concrete that perfectly substitutes industrial by-products such as ground granulated blast furnace slag (GGBFS) for cement are being actively made. AAS concrete is possible to have high strength development at room temperature, however, it is difficult to ensure the working time due to the fast setting time and the loss of workabillity because of the alkali reaction. In this study, the early age properties of alkali activated slag mortar are investigated to obtain the fundamental data for AAS concrete application to structural members. The water-binder ratio (W/B) was fixed at 0.35 and sodium hydroxide and waterglass as alkali activator was used. The compressive strength, the flow and the ultrasonic pulse velocity were measured according to the type of superplasticisers, which were naphthalene(N), lignin(L), melamine(M) and PC(P), up to a maximum of 2 percent by the mass of GGBFS. The results showed that adding melamine type of superplasticizer improved the fluidity of AAS mortar without decreasing the compressive strength, while naphthalene and polycarbonate type of superplasticizer had little effect on the fluidity of AAS mortar.

• Journal of the Korean Ceramic Society
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• v.42 no.3 s.274
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• pp.182-187
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• 2005

There are many kinds of polycarboxylate superplasticizer as a functional classification which are introduced to domestic; Water Reducer, Retention, Ultra High Strength Superplasicizer. These are showed different physical behaviors because of the difference in the chemical system and the manners after cement mixing. In the case of water reducer, when $1.2\% of cement weight used, water reducing which is over $30\% is observed, but it take with segregation and the reduction of slump flow shows over 30 cm after 45 min of concrete produce. In the case of retention, when the same quantity used, water reducing which is about $25\% is observed and slump flow which is up to 45 min shows under 15 cm. And in the case of ultra high strength, when $1.2\% of cement weight used, water reducing which is over $30\% is observed, and slump flow which is up to 45 min recorded fewer than 15 cm. Compressive strength of ultra high strength superplasticizer has take effect of early age strength, and in the condition of specific mixing, 18 h-compressive strength is insured for more than $60\;Kgf/cm^2$ and 24 h-compressive strength is insured for more than $80\;Kgf/cm^2$.

• Journal of the Korea Concrete Institute
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• v.27 no.1
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• pp.65-73
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• 2015

This study discussed the pozzolanic properties of calcined sewage sludge (CSS) according to calcination and fineness conditions. The chemical and mineralogical analysis of CSS according to calcination temperature and time were carried out and compared with that of the existing pozzolanic materials such as fly-ash, blast furnance slag and meta-kaolin. Various mortars were made by mixing those CSS and $Ca(OH)_2$ (1:1 wt. %), and their compressive strength and hydrates according to experimental factors such as fineness of CSS and curing age were also investigated in detail. The results show clearly the potentiality of calcined sewage sludge (CSS) as an admixture materials in concrete, but the CSS should be controlled by calcination temperature and time, and fineness etc. In this experimental condition, the calcination temperature of $800^{\circ}C$, calcination time of 2 hours and fineness of $5,000cm^2/g$ were optimum conditions in consideration of the mechanical properties and economic efficiency of CSS. The compressive strength of CSS mortars was higher than that of fly-ash mortars and blast furnace slag mortars, especially at the early ages. Then, the utilization of CSS in construction fields was greatly expected.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.4
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• pp.132-139
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• 2017

In this study, in order to prevent the frost damage of the concrete, the characteristics of the form using heating sheet utilizing the chemical reaction of quicklime and the insulation were evaluated through experiments at low temperature. In the case of form at $-10^{\circ}C$, the form with attached heating sheet showed a temperature history of more than $10^{\circ}C$ higher than that of wood form at the early of concreting due to heat of the quicklime in the heating sheet. In the case of the insulated form, the concrete was kept at a high temperature by preserving the hydration heat. When the heating sheet and the isopink(extruded polystyrene) were attached together on the form, the effect was the same as that of the vacuum insulation. The compressive strength of the form with vacuum insulation and form with isopink, heating sheet as measured about 5 MPa at age 3. The experimental in Mongolia, as with the pervious results, the form with the heating sheet and the insulation showed the highest temperature history over $25^{\circ}C$ for 48 hours. Therefore, it was confirmed that the heating sheet and insulation are attached to the form, which helps the concrete strength development at low temperature by heat generation and the insulation effect.