• International Journal of Concrete Structures and Materials
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• 제6권4호
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• pp.239-246
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• 2012

Pervious concrete is a tailored-property concrete with high water permeability which allow the passage of water to flow through easily through the existing interconnected large pore structure. This paper reports the results of an experimental investigation into the development of pervious concrete with reduced cement content and recycled concrete aggregate for sustainable permeable pavement construction. High fineness ground granulated blast furnace slag was used to replace up to 70 % cement by weight. The properties of the pervious concrete were evaluated by determining the compressive strength at 7 and 28 days, void content and water permeability under falling head. The compressive strength of pervious concrete increased with a reduction in the maximum aggregate size from 20 to 13 mm. The relationship between 28-day compressive strength and porosity for pervious concrete was adversely affected by the use of recycled concrete aggregate instead of natural aggregate. However, the binder materials type, age, aggregate size and test specimen shape had marginal effect on the strength-porosity relationship. The results also showed that the water permeability of pervious concrete is primarily influenced by the porosity and not affected by the use of recycled concrete aggregate in place of natural aggregate. The empirical inter-relationships developed among porosity, compressive strength and water permeability could be used in the mix design of pervious concrete with either natural or recycled concrete aggregates to meet the specification requirements of compressive strength and water permeability.

• 한국식품영양학회지
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• 제16권3호
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• pp.171-179
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• 2003

본 실험에서는 천연 추출물중 항산화성이 우수한 추출물을 선발하여 계육 양념육 제품을 개발하고, 둘째. 양념육의 침투속도를 높이기 위하여 수용성 미네랄 성분과 Ge-132를 이용하여 양념계육 제품에 대한 이화학적 특성을 검토하였다. 이상의 게르마늄, 녹차, 수용성 미네랄 및 녹차+게르마늄+수용성 미네랄 복합 첨가 양념 닭고기 제품의 이화학적 결과를 보면, pH는 염지전 가슴부분이 6.00～5.94, 다리부분이 6.55～6.38로 염지 기간 중 처리구간의 pH의 차이는 나타나지 않았으며, 닭고기 부위에 따른 차이는 가슴부분보다 다리부분이 조금 높게 나타났다. 염도와 당도는 염지기간 중 증가하는 경향이었으며, 염도의 경우 염지 24시간째 대조구의 가슴과 다리부분이 각각 1.11%, 1.21%를 나타내었다. 그러나 수용성 미네랄 첨가구 모두 저장 6시간과 12시간째 대조구의 염도보다도 높은 값을 나타내었다. 당도의 경우도 마찬가지로 대조구 24시간째 19.94 brix, 18.89 brix를 저장 6시간째 천연물과 기능수 첨가구 모두 가슴과 다리부분에서 높은 당도를 나타내었다. 가열조리 후 각 처리양념 닭고기제품의 경도 변화는 대조구에 비하여 모든 처리구가 부위에 관계없이 낮은 값을 나타내 었으며 특히, 녹차 첨가구는 가슴부분과 다리부분이 각각 122.59, 142.59kg/$cm^2$로 가장 낮은 값을 나타내었다. 항균성의 경우 대조구의 가슴부분 4.23CFU/g, 다리부분 4.24CFU/g에 비하여 가슴부분은 녹차 첨가구가 3.76CFU/g, 녹차+게르마늄+수용성 미네랄 복합첨 가구가 3.61CFU/g으로 낮은 값을 나타내었고, 다리부분은 녹차 첨가구가 3.49CFU/g, 녹차+게르마늄+수용성 미네랄 복합 첨가구가 3.55 CFU/g으로 낮은 값을 나타내었다. 지방산화도의 경우는 부위에 관계없이 대조구에 비하여 낮은 TBARS값을 나타내었고 특히, 녹차 첨가구가 가슴부분 0.43, 다리부분 0.47로 TBARS값이 낮게 나타났다. 다즙성, 연도 및 종합적인 기호도에서는 대조구에 비하여 녹차, 수용성 미네랄 및 녹차+게르마늄+수용성미네랄 복합 첨가구가 양념 닭고기제품의 다리와 가슴부분 모두에서 유의하게 높은 수치를 나타내었다. 대조구의 유리아미노산 함량 1462.7mg에 비하여 녹차첨가구의 유리아미노산 함량은 1661.46 mg으로 증가하였고, 고기의 추출물에서 맛과 풍미에 중요한 역할을 하는 아미노산인 glutamic acid의 함량이 대조구에 비하여 녹차 첨가구가 534.24mg으로 높은 값을 나타내었다.

• 청정기술
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• 제8권2호
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• pp.67-76
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• 2002

Dewatered sludge of 400,000t/y from water treatment plants in Korea is being disposed through landfill and ocean dumping. However, the disposal is posing more and more serious environmental problems at the same time not only because of landfill site shortage in municipal suburbs, but because of the concern it will contaminate the oceans. In this study, the research on utilizing the sludge dried by flash dryer as covering soil in the landfill sites was carried out to solve these problems on environmental affinity. Both dewatered and dried sludge were exposed to the natural condition and observed according to the atmospheric changes. An experiment of soil engineering characteristics of the dried sludge and tests on mixed sludge(silty sandy soil : dried sludge = 10:90 ~ 30:70) such as particle size distribution, liquid and plastic limit, moisture content, specific gravity and compaction test were carried out. According to the compaction test, the compaction was confirmed as the optimum water content ratio was observed in the condition of SM-silty sand of particle size distribution, NP of liquid and plastic limit, 101.4% of moisture content, 2.04~2.12 of specific gravity. The results showed that dried sludges mixed with at least 30% of natural soil could be used as daily covering soil in the landfill sites.

• 한국농촌건축학회논문집
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• 제21권1호
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• pp.37-44
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• 2019

Recently, various tourist products using hanok have increased rapidly. In the meantime, there is a steady demand for Hanok architecture. However, there are many negative perceptions about wood deformation and biodeterioration. Wood deformation and biodeterioration are related to moisture content. And the cracks occur in the process of removing water from the wood. Therefore, this study investigates the moisture content and cracks of dried hanok made of wood according to the drying method of wood. Drying methods include natural seasoning and artificial seasoning. There was a difference in moisture removal depending on drying period and method of natural seasoning. Drying time should be about 3 years for natural seasoning, so the moisture content of the wood is stable. In addition, the moisture absorption rate was low even in a humid environment where the voids were removed. However, natural seasoning is time consuming. Artificial seasoning, on the other hand, can quickly remove moisture from the wood and reduce porosity, but it is costly. Cracks that occur during the drying of wood may become problematic in appearance and stability due to wider spacing over time. As a result, the difference in the moisture content of the timber depending on the drying method and drying period of the wood was maintained even after the formation. These gaps appeared to be differences in moisture absorption in a wet environment.

• Journal of Radiation Protection and Research
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• 제38권4호
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• pp.185-188
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• 2013

Heating method using electric heater was used to reduce water content in fingernail clippings. Authors found that low water content is helpful to measure EPR signal of fingernail sample with enhanced variability. Generally, natural dehydration happens in normal room condition at least one month and needs much time for using in experiment. So, artificial heating method is applied in this study for time savings. Fingernail samples were tested to find effect of water content to the EPR signal on microwave power levels for dosimetry. Low water content in fingernail reduced variability of EPR signal and makes it possible to measure accurate EPR signal. It also made it possible to measure constant movement of EPR signals on several microwave power levels. Although this method was difficult to apply directly in fingernail/EPR dosimetry, we, authors, believe that this heating method would be useful to differentiate MIS2 and RIS which are generally located at the same g-factor and almost impossible to be identified with each other.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1194-1196
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• 2003

Variations in soil physical and chemical properties can affect agricultural productivity and the environmental implications of crop production. These variations are present and may be important at regional, field, and sub-field (precision agriculture) scales. Because traditional measurements are time-consuming and expensive, reflectance-based estimates of soil properties such as texture, organic matter content, water content, and nutrient status are attractive. Soil properties have been related to reflectance measured with laboratory, in-field, airborne, and satellite sensors. Both multispectral and hyperspectral instruments have been used, with both natural and artificial illumination. Varying levels of accuracy have been obtained, with the best results (r > 0.95) using hyperspectral reflectance data to estimate soil organic matter and water content.

• Bulletin of the Korean Chemical Society
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• 제29권6호
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• pp.1233-1242
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• 2008

The hydration effect on the intrinsic magnetism of natural salmon double-strand DNA was explored using electron magnetic resonance (EMR) spectroscopy and superconducting quantum interference device (SQUID) magnetic measurements. We learned from this study that the magnetic properties of DNA are roughly classified into two distinct groups depending on their water content: One group is of higher water content in the range of 2.6-24 water molecules per nucleotide (wpn), where all the EMR parameters and SQUID susceptibilities are dominated by spin species experiencing quasi one-dimensional diffusive motion and are independent of the water content. The other group is of lower water content in the range of 1.4-0.5 wpn. In this group, the magnetic properties are most probably dominated by cyclotron motion of spin species along the helical π -way, which is possible when the momentum scattering time (${\tau}_k$) is long enough not only to satisfy the cyclotron resonance condition (${\omega}_c{\tau}_k$ > 1) but also to induce a constructive interference between the neighboring double helices. The same effect is reflected in the S-shaped magnetization-magnetic field strength (M-H) curves superimposed with the linear background obtained by SQUID measurements, which leads to larger susceptibilities at 1000 G when compared with the values at 10,000 G. In particular, we propose that the spin-orbital coupling and Faraday's mutual inductive effect can be utilized to interpret the dimensional crossover of spin motions from quasi 1D in the hydrate state to 3D in the dry state of dsDNA.

• 한국물환경학회지
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• 제32권5호
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• pp.442-449
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• 2016

The goal of this study is to provide basic data to establish a foundation for the provision of safe drinkable water. The raw water of natural mineral water was analyzed to determine the quantities of anions (F^-, Cl^-, NO_3-N^-, and SO₄^2- ) and cations (Ca²⁺, K⁺, Mg²⁺, and Na⁺) during the former and latter half of 2016. Analysis of the current quality of the raw water of natural mineral water among domestic manufacturers showed average anions contents of 0.46mg/L of fluorine, 8mg/L of chlorine ion, 1.5mg/L of nitrate nitrogen, and 12mg/L of sulfate ion. While the fluorine content was greater than the water quality criterion of 2.0mg/L at four points, the fluorine level was overall stable. The average cations contents included 21.3mg/L of calcium, 1.0mg/L of potassium, 3.4mg/L of magnesium, and 9.6mg/L of sodium. The chemical characteristics were compared among the major ions, and the results are presented in a piper diagram. The content ratio of cations was in the order of Ca²⁺> Na⁺>Mg²⁺>K⁺, whereas that of anions was in the order of SO₄^2->Cl^->NO_3-N^->F^-. While the cations were slightly scattered, the anions were generally concentrated except for at a few points. The Ca-Na-HCO₃ type was dominant overall in water sources from diorite, gneiss, and granite, while the Na-Mg-Ca-HCO₃-Cl type was dominant in basalt sources. Mineral water manufacturers source their water under various conditions, including in-hole casing, excavation depth, and contact state of bedrock; even within the same rocky area, some differences in the water quality type can occur. When the depth of the water source was taken into account, the mean anions contents of F^-, Cl^-, NO_3-N^-, and SO₄^2- were similar, with no significant differences according to depth. Of the cations, K⁺ and Na⁺ showed no significant differences across all the tubular wells, whereas Ca²⁺ and Mg²⁺ decreased in content with depth.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.128-134
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• 2005

This study was performed to evaluate the strength and durability properties of recycled concrete containing water - redispersible copolymer powder(WRP) and blast furnace slag powder(BSP) [RCWS]. Material used were cemente, recycled coarse aggregare, natural fine aggregate, water-redispersible copolymer powder, blast-furnace slag powder. Especially, Water-redispersible powder was used for blending with Inorganic binders such as cemente, gypsum and hydrated lime etc. First of all, Mixed ratio method of RCWS made Two Type. One was called type-1 which used to BSP content 5% and WRP(Water-redispersible powder) content 0%, 1%, 2%, 3%, 4%, 5%, 6%. respectively. Another was called Type-2 which used to BSP(blast furnace slag powder)content 10% and WRP(Water-redispersible powder) content 0%, 1%, 2%, 3%, 4%, 5%, 6%. respectively. According to the experimental results of (RCWS), Incase Type-2 at curing age 28days, Compressive strength, pulse velocity and dynamic modulous of elasticity were shown higher than Type-1 and The more WRP content increasing($0%{\sim}6%$) was the lower Compressive strength, Pulse velocity and Dynamic modulous of elasticity. Water absorption ratio was in the range of $3.85%\;{\sim}\;3.23%$, it was almost equal to Type-1, 2 but Increasing the WRP content($0%{\sim}6%$), The water absorption ratio is decreased.

• 한국식품위생안전성학회지
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• 제12권1호
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• pp.55-62
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• 1997

This study was carried out to investigate the microbiological and chemical properties of natural water during storage. The water samples were taken at the time of purchase and the opened bottles and unopened bottles stored at the temperature of 4$^{\circ}C$, 18$^{\circ}C$, and 3$0^{\circ}C$. The bacterial content normally rose to 2.06$\times$102 CFU/$m\ell$ for the unopened bottles and 2.91$\times$102 CFU/$m\ell$ for the opened bottles after 2 weeks of storage, and 1.21$\times$102 CFU/$m\ell$ and 2.64$\times$102, respectively, after 24 weeks of storage. The number of viable cells of bacteria peaked more rapidly at the storage temperature of 3$0^{\circ}C$ than 18$^{\circ}C$. But the total samples were found to be negative for coliforms test during the study period. The average range of pH value was from 7.39 to 7.76. The results showed that the nitrates and chlorides satisfied the Korea Drinking Water Quality Standards during the storage period of 24 weeks. However, the undesirable changes of the taste and odor were detected within 2 weeks and 3 weeks, respectively.