• Journal of the Korea Concrete Institute
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• v.23 no.1
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• pp.121-127
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• 2011

In this study, possible use of indigenous natural loess (Hwangtoh) as a new binding material via geopolymerization process is examined. Hwangtoh pastes with four different mix proportions of varying alkali liquid concentrations (6 M, 8 M) and the constituents of the binder as well as the alkali liquid at a constant liquid-to-binder ratio of 0.55 were prepared. Analysis of the natural loess (Hwangtoh) paste was carried out as follows : 1) Measurement of compressive strength and weight of cubic specimens versus curing time; 2) Analysis by X-ray diffraction (XRD) and scanning electron microscope (SEM) about reaction product; 3) Porosity analysis of hardened Hwangtoh paste. The result showed that it is possible to prepare Hwangtoh paste with 29.1 MPa at the age of 7 day by using alkali solution (made as 1 : 4.5 the mass ratio of liquefied $Na_2SiO_3$ and NaOH solution and applying the curing temperature of $60^{\circ}C$). Compressive strength development with respect to the degree of moisture evaporation from the paste seems to be independent of curing temperature. Therefore, it seems that higher early strength of the paste specimens cured at higher temperature can be attributed to both higher rate of reaction and moisture evaporation.

• Journal of the Korean Geographical Society
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• v.33 no.3
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• pp.377-394
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• 1998

The magnetic record of loess deposits may be one of the most detailed and useful records of Quatermary climate change on the continents. Stratigraphic variations of magnetic parameters define alternating zones of high and low concentrations of magnetic minerals. All the concentration-sensitive magnetic parameters show an increase within the interstadial Gilman Canyon Formation and interglacial Brady soil and a systematic decrease within the Wisconsinan Peoria loess. The influence of climate change on magnetic records is confirmed by a high correlation between the magnetic parameters and biological proxies. Rock magnetic data appear to be better correlated with temperature-sensitive biological proxies than does a precipitation-sensitive index such as the aridity index derived from opal phytoliths. Simultaneous, higher resolution sampling of magnetic and biological proxies proved to be a better sampling tactic, and enhanced the feasibility of rock magnetic parameters as independent climate proxies.

• Food Science and Biotechnology
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• v.17 no.5
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• pp.1010-1015
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• 2008

The effects of heat treatment on the physicochemical properties and mineral composition of sun-dried salt were investigated. The salts parched at high temperature were appeared the higher alkalinity and the lower oxidation-reduction potential (ORP) than the samples without heat treatment. The commercial salts (bamboo salt and yellow loess salt) and the sun-dried salt parched at high temperature had relatively higher sodium ion content (418-450 ppm) compared to that (418.0 ppm) of refined salt. The increase of calcium ion occurred in the salts parched at high temperature compared to the sun-dried salt without heat treatment, but the magnesium ion was vice versa. The commercial salt, yellow loess salt had highest turbidity (0.973) whereas sun-dried salt showed lowest level (0.097) among the tested samples. Turbidity of heat treatment samples decreased as solubility increased. The maximum concentration of dialyzed salt was reached after 4 hr regardless of various processed salts, but those had no difference significantly among the tested samples. The X-ray diffraction patterns of the parched sun-dried salts showed different peak intensity with common salts, and they were similar to the patterns of oxide salts, especially MgO. The maximum value (2.56%) of MgO appeared in the sun-dried salt parched at $1,400^{\circ}C$.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.107-108
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• 2017

In this search, by evaluating the field applicability of soil mixed pavement of Red mud is mixed into the soil mixed pavement field applicability, and tries to present the basic data about the site application of recycling of red mud and low carbon construction material to. As a result, the conventional soil concrete organization standards (SPS-KSCICO-001: 2003) meets the criteria for parking lot, making use of red mud, natural color as well as the natural loess is expressed.

• Journal of the Korea Institute of Building Construction
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• v.12 no.5
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• pp.503-509
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• 2012

In this study, the potential use of indigenous natural loess(Hwangtoh) as a new construction material, via alkali activation in conjunction with microwave heating, was investigated. Hwangtoh pastes with three different mix proportions of varying alkali liquid concentrations at a constant liquid-to-Hwangtoh ratio of 0.55 were prepared. Through the investigation it was found that it is possible to prepare Hwangtoh paste with $19.02N/mm^2$ at the age of 4 hours with the alkali solution of 8M NaOH and 1:4.5 mass ratio of liquefied $Na_2SiO_3$ at the curing temperature of $60^{\circ}C$ by microwave heating. The strength development at early age of the alkali activated Hwangtoh paste specimens may be attributed to both a higher rate of reaction and moisture evaporation due to microwave heating.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.96-97
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• 2015

In this search, by evaluating the field applicability of soil mixed pavement of Red mud is mixed into the soil mixed pavement field applicability, and tries to present the basic data about the site application of recycling of red mud and low carbon construction material to. As a result, the conventional soil concrete organization standards (SPS-KSCICO-001: 2003) meets the criteria for a bicycle road, making use of red mud, natural color as well as the natural loess is expressed.

• Fashion & Textile Research Journal
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• v.14 no.4
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• pp.669-676
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• 2012

This study aims to compare the properties of natural dye stuffs, such as color, dyeability, fastness, and marketability, to analyze the differences noted by expert groups regarding the properties of the stuffs, and to make a positioning of the stuffs. A survey of experts in academia, business, and the art of natural dyeing was conducted, with an evaluation of 23 types of the stuff's properties. There is a correlation between the properties of the stuffs, and evaluating dye stuffs differs according to the group to which it belongs. X-axis relates to color and Y-axis refers to fastness in the positioning of the stuff. There are different relationships between properties according to their group. Color is significantly associated with marketability in art experts however, fastness is closely connected with marketability in business. The stuffs can be divided into five clusters. Cluster I includes indigo and persimmon, and is marked by excellent color, dyeability, fastness, and marketability, Cluster II contains safflower and sappan wood, which are excellent colors, yet suffer from low marketability on account of their medium to low fastness. Cluster III includes red, purple, and brown dyes, and onion and rhubarb, and has medium properties. Cluster IV is mugwort and yellow dyes, except onion and rhubarb, and features low properties. Cluster V is loess, featuring medium color and low fastness.

• Journal of the Korean Institute of Oriental Medical Informatics
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• v.16 no.1
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• pp.105-133
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• 2010

Koreans has regarded a fair skin as the supreme beauty emphasizing the white beauty so long, and mugwort and garlic were used as whitening materials. Also, it was recorded that the people of Eub-Rue (挹婁) applied some lard to protect their skin from cold and prevent frostbite, and this must be a great way of beauty care in the light of modern sense. The basic beauty care materials currently used as skin care materials, include natural minerals like loess or mud, and the ones composed of a highly polymerized compound. However, by reason that they are produced without consideration of an individual skin condition, and rather bring about a number of problems leading to skin diseases. To complement this issue, using natural resources would have priority to make up for the weak points. For this, we decided to select and study "Dongeuibogam".

• Atmosphere
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• v.34 no.2
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• pp.107-121
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• 2024

In this study, we empirically analyzed the impact of physical risks due to climate change on the soundness and operational performance of the financial industry by combining economics and climatology. Particularly, unlike previous studies, we employed the Seasonal-Trend decomposition using LOESS (STL) method to extract trends of climate-related risk variables and economic-financial variables, conducting a two-stage empirical analysis. In the first stage estimation, we found that the delinquency rate and the Bank for International Settlement (BIS) ratio of commercial banks have significant negative effects on the damage caused by natural disasters, frequency of heavy rainfall, average temperature, and number of typhoons. On the other hand, for insurance companies, the damage from natural disasters, frequency of heavy rainfall, frequency of heavy snowfall, and annual average temperature have significant negative effects on return on assets (ROA) and the risk-based capital ratio (RBC). In the second stage estimation, based on the first stage results, we predicted the soundness and operational performance indicators of commercial banks and insurance companies until 2035. According to the forecast results, the delinquency rate of commercial banks is expected to increase steadily until 2035 under assumption that recent years' trend continues until 2035. It indicates that banks' managerial risk can be seriously worsened from climate change. Also the BIS ratio is expected to decrease which also indicates weakening safety buffer against climate risks over time. Additionally, the ROA of insurance companies is expected to decrease, followed by an increase in the RBC, and then a subsequent decrease.

• Analytical Science and Technology
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• v.21 no.6
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• pp.474-479
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• 2008

Radioactivity of naturally occurring radioactive nuclides (NORN) such as $^{226}Ra$, $^{228}Ac$ and $^{40}K$ were investigated for surface sediments collected from Ordos, Alashan, Taklimakan deserts and Loess plateau regions in China. By a Gamma-ray spectrometry, specific activity (SA) and SA ratio (SAR) of the NORN were determined for each source region of Asian dust. Characterization of the source regions of Asian dust was performed with the SA and SAR values. SA of $^{226}Ra$ in the three desert regions have almost same values in the range of mean value 17.9~21.9 Bq/kg, however, the SA in Loess Plateau has much higher values in the mean value of 35 Bq/Kg. SA of $^{228}Ac$ in the Ordos and Alashan desert regions have almost same values in the range of mean value 27.1~27.2 Bq/kg, and those in Taklimakan desert and Loess Plateau were 31.7 and 49.0 Bq/kg, respectively. In case of 40K, the SA in all regions have similar values in the range of 636~943 Bq/kg. The mean SAR value of $^{226}Ra/^{228}Ac$ in four source regions was almost same in the range of 0.708-0.721. It is shown that relationship between $^{226}Ra$ and $^{228}Ac$ is clearly presented in the source regions. The mean SAR values of $^{226}Ra/^{40}K$, $^{228}Ac/^{40}K$ are 0.0209-0.056, 0.0287-0.0773, respectively.