• 헤리티지:역사와 과학
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• 제36권
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• pp.267-297
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• 2003

The plain coarse pottery from the Unjeonri Bronze Age relic sites in the Cheonan, Korea were studied on the basis of clay mineralogy, geochemistry and archaegeological interpretations. For the research, the potteries are utilized at the analysis for 6 pieces of plain coarse potteries. Color of the these potteries are mainly light brown, partly shows the yellowish brown to reddish brown. The interior, surface and inside of the pottery appear as different colors in any cases. Original source materials making the Unjeonri potteries are used of mainly sandy clay soil with extreme coarse grained irregularly quartz and feldspar. The magnetic susceptibility of the Unjeonri pottery range from 0.20 to 1.20. And the Unjeonri soil's magnetic susceptibility agree almost with 0.20 to 1.30. In the same magnetization of soil and pottery, the results revealed that the Unjeonri soil and low material of pottery are same produced by identical source materials. The Unjeonri potteries and soil are very similar patterns with all characteristics of soil mineralogy, geochemical evolution trend. The result seems to be same relationships between the behavior and enrichment patterns on the basis of a compatible and a incompatible elements. Consequently, the Unjeonri potteries suggest that made the soil to be distributed in the circumstance of the relic sites as the raw material are high in a greater part. In the Unjeonri soil, the kaolinite is common occurred minerals. However, in the Unjeonri pottery, the kaolinite was not detected in all broken pieces. The kaolinite was presumed to destroy crystal structure during the firing processes of over $550^{\circ}C$. The quartz is phase transition from ${\alpha}$-quartz to ${\beta}$-quartz at $573^{\circ}C$, but the Unjeonri pottery did not investigated any phase transition evidences of quartz. The chorite was detected within the mostly potteries and soils. As the results, the Unjeonri potteries can be interpreted by not experiencing a firing temperature over $800^{\circ}C$. The colloidal and cementing materials between the quartz and low materials during the heating did not exist in the internal part of the potteries. An any secondary compounds by heating does not appear within the crack to happen during the dry of the pottery. The hyphae group are kept as it is with the root tissue of an organic matters to live in the swampy land. In the syntheses of all results, the general firing condition to bake and make the Unjeonri pottery is presumed from $550^{\circ}C$ to $800^{\circ}C$. However, the firing condition making the Unjeonri pottery can be different firing temperature partially in one pottery. Even, the some part of the pottery does not take a direct influence on the fire.

• 한국지반공학회논문집
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• 제25권12호
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• pp.57-67
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• 2009

최근 시공기술이 발전함에 따라 댐 축조재료로 사용되는 조립재료의 최대입경은 수cm에서 1m이상에 달하고 있다. 실제 현장 원입도 시료에 대한 시험을 실시하는 것은 비용적으로 고가일 뿐만 아니라 기술적으로도 많은 문제가 존재하므로 일반적으로 상사입도 시료에 대하여 실내시험을 실시하고 그 결과를 실제 지반구조물의 설계 및 해석에 적용한다. 지반구조물에 대한 보다 정확한 거동특성을 예측하기 위해서는 입자크기에 따른 전단거동 특성의 변화를 파악하는 것이 필수적이라고 할 수 있다. 이에 본 연구에서는 국내 B댐 현장 댐 축조시료인 하상 사력재에 대하여 최대입경을 서로 달리하여 재구성한 상사입도시료를 대상으로 같은 상대밀도로 공시체를 제작하여 대형삼축시험을 실시하였으며, 최대입경의 변화에 따른 상사입도시료의 응력-변형특성, 전단강도특성을 비교.분석하였다. 시험결과 조립재료는 전단과정에서 응력연화 및 체적팽창 거동을 나타내고, 상사입도 시료의 최대입경이 증가할수록 그 현상이 더욱 뚜렷한 것으로 나타났다. 내부마찰각, 전단강도는 상사입도 시료의 최대입경이 증가함에 따라 증가하는 것으로 나타났다.

• Journal of Welding and Joining
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• 제34권6호
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• pp.47-54
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• 2016

Post-Weld Heat Treatment (PWHT) cracking susceptibility in the weld heat-affected zone (HAZ) of reduced activation ferritic-martensitic (RAFM) steels was evaluated through stress-rupture tests. 9Cr-1W based alloys including different C, Ta and Ti content were prepared. The coarse grained heat-affected zone (CGHAZ) samples were simulated with welding condition of 30 kJ/cm heat input. CGHAZ samples consisted of martensite matrix. Stress rupture experiments were carried out using a Gleeble simulator at temperatures of $650-750^{\circ}C$ and at stress levels of 125-550 MPa, corresponding to PWHT condition. The results revealed that PWHT cracking resistance was improved by Ti addition, i.e., Ti contributed to the formation of fine and stable MX precipitates and suppression of coarse M23C6 carbides, resulting in improvement of stress rupture ductility. Meanwhile, rupture strength increased with increasing solute C content.

• 자원환경지질
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• 제9권3호
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• pp.157-163
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• 1976

In this study, the oil bearing rock-sequence, U-hand-ri Formation (D.S. Lee et al., 1976), was subdivided into three members; the lower, the intermediate and the upper. The lower consists mainly of reddish purple tuff and sandy calcareous shales, the intermediate of an alternation of tuffs, sandstons, calcareous black shales, cherts and limestone and the upper of coarse grained variegated tuff and agglomerate. Oily matter was found from the black shales of the intermediate. Ten samples of black shales from drilled cores, 8 samples of black shales from different outcrops of the member, and 1 sample of grease-like seeping oil from black shales at U-hang-ri coast were chemically analyized. Among them, 9 samples contain remarkable amount of organic carbon (0.96~1.60%) and E.O.M. extract (0.176~0.718%), and mostly the bituminous material is saturated hydrocarbons as well as shown in infared spectroscopic analyses. The elemental analyses of MAE extracts and asphaltenes of some of thoese samples indicate that the transformation of organic material to crude oil is highly progressed. The authors suggest that the seeping oil and oily tinges in black shale layers are the products of natural cracking related with the igneous activities in the area nearby.

• 보존과학회지
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• 제36권1호
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• pp.60-72
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• 2020

The Inscribed stones of Hanyangdoseong has been weathered for a long time because of external environment and living organisms. To establish a long-term conservation-management strategy for the inscription stones, the material characteristics of the inscription stones of Naksan Mountain Area were identified, and its deterioration state was diagnosed. Consequently, it was confirmed that the Inscription stones of Naksan Mountain Area mainly comprised coarse-to medium-grained pinkish granite and biotite granite, and, in part, comprised reddish granite, quartz porphyry, and aplite. Presently, the Inscription stones of Naksan Mountain Area, Hanyangdoseong, is undergoing a considerable decrease in physical properties because of physical, chemical, and biological weathering. Moreover, it has been confirmed that the type of damage, such as blistering, soiling, and dicolouration, on the surface shows a significantly high deterioration rate, and that conservation treatment might be required in future. In addition, because the possibility of damage recurrence is high even after the treatment, the conservation state must be regularly monitored.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1042-1049
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• 2007

Recently, a theoretically-sound design approach, using an elastic multilayer model, is attempted in trackbed designs for the construction of high speed railways and new lines of conventional railways. In the elastic multilayer model, the stress-dependent resilient modulus($E_R$) is an important input parameter, that is, reflects substructure performance under repeated traffic loading. However, the evaluation method for resilient modulus using repeated loading triaxial test is not fully developed for practical purpose, because of costly equipment and the significantly fluctuated values depending on the testing equipment and laboratory personnel. In this study, the paper will present an indirect method to estimate the resilient modulus using dynamic properties. The resilient modulus of crushed stone, which is the typical material of sub-ballast, was calculated with the measured dynamic properties and the range of stress level of the sub-ballast, and approximated with the power model combined with bulk and deviatoric stresses. The resilient modulus of coarse grained material decreases with increasing deviatoric stress at a confining pressure, and increases with increasing bulk stress. Sandy soil(SM classified from Unified Soil Classification System) of subgrade was also evaluated and best fitted with the power model of deviatoric stress only.

• 비파괴검사학회지
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• 제20권5호
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• pp.390-396
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• 2000

원자로 재료인 SA 508 Class 3 강용접부 및 열영향부 모사 시험편에 대해서 초음파공명분광법으로 동적탄성계수를 측정하였다. 등방성 탄성계수를 가정하여 초기 추정 탄성 계수, $c_{11},\;c_{12}$ 및 $c_{44}$로부터 장방형 시편의 공명 주파수를 계산하였으며 계산된 주파수와 초음파공명분광법으로 측정된 주파수를 비교, 반복 수렴 절차를 거쳐 정밀한 탄성계수를 구했다. 열처리 조건의 차이 및 미세 조직의 차이에 따라 영률 및 전단 계수의 차이가 확실하게 나타났다. 미세한 베이나이트 조직에서의 영률 및 전단 계수는 조대한 마르텐사이트 조직보다 높았으며 이러한 경향은 미세 경도 시험 등의 다른 실험 결과와도 일치하였다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제24권1호
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• pp.35-42
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• 2019

In installation of groundwater wells, grouting materials are injected between the groundwater borehole and the inner casing in order to prevent infiltration of contaminated groundwater from the top soil layers into wells. The injection device of grouting materials is commonly composed of an inlet head device with an expansion packer, a cylinder capable of storing the grouting materials, and an air cylinder. In this work, two types of common grouting materials, silicon and cement materials, were tested for their performances as grouting media. For silicon. silicon was mixed with clay or calcite, and tested for their tensile strength and underwater reactivity. Both silicon-clay and silicon-calcite mixtures had adequate flow and adhesiveness. For cement material, general cement, ultra-rapid harding cement, and natural cement were respectively mixed with three different soil types including coarse-grained granite, fine-grained granite, and gneiss, and direct shearing tests were conducted after hardening. Under grouting depth condition of 30 m, the minimum adhesive strength was greater for weathered gneiss than non-weathered gneiss with its maximum values obtained from the mixtures of ultra rapid-harding cement.

• 암석학회지
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• 제15권3호
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• pp.139-153
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• 2006

서울특별시 종로구 훈정동에 위치한 종묘는 세계문화유산으로 등록되어 있다. 이 연구에서는 종묘의 어도에 깔려 있는 약 2,361개의 박석에 대해 규격과 재질특성을 규명하고자 하였다. 박석에서는 암종, 암색, 입도, 광물조성, 화학조성, 대자율, 박석의 크기, 표면상태, 파손상태 등이 조사를 실시하여 박석의 특성을 해석하고, 박석의 규격조건을 설정하였다 박석은 4종의 화강암류, 즉, 담회색 세중립질 각섬석흑운모화강암, 담회색 세중립질 흑운모화강암, 담홍색 중립질 내지 중조립질 흑운모화강암, 홍색 중립질 내지 중조립질 흑운모화강암과 페그마타이트, 편암류로 구성된다. 이들 중 화강암이 99.8%이다. 박석의 평균크기는 $65{\times}46cm$(표준편차 $12{\times}7cm$)이며, 박석의 표면상태는 양호 34.7%, 보통 41.4%, 보통 이하 23.8%이다. 종묘 삼도박석에서 2조각 이상으로 깨져 있는 박석은 약 720장 30.5%이다. 담홍색과 홍색을 띄는 흑운모화강암, 화강암 이외의 암석과 표면상태가 보통이하인 박석은 원래의 박석부재는 아니었을 것으로 생각되며 후세에 보수 과정에서 교체된 것으로 보인다. 이러한 박석의 수는 약 560여장이다. 박석의 주요 부재로 사용할 수 있는 화강암의 규격은 담회색 흑운모화강암(미량의 각섬석 허용)으로 입도는 세중립질$(0.5{\sim}3mm)$이며, 구성광물은 석영, 사장석, 미사장석, 퍼다이트, 흑운모 등으로 된 IUGS 분류상의 화강암 영역에 속해야 할 것으로 판단된다. 또한 $SiO_2$ 성분은 70wt.% 이상, 대자율은 $0.1{\tims}10^{-3}\;SI$ 내외(최대 $2{\times}10^{-3}\;SI$ 내외 허용)의 암석이 가장 적절 할 것으로 생각된다.

• 한국수산과학회지
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• 제40권3호
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• pp.160-166
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• 2007

The coarse deposit with a lower mud content adjacent to the shelf of the southern East Sea is probably a "relict" sediment deposited in response to a lower stand of sea level during the Pleistocene. The sediment that developed on the slope and in the deep sea was river-borne primarily and was secondarily reworked or redistributed by the Tsushima Warm Current from the East China Sea. The clay mineralogy of the area suggests various sources of fine-grained sediment from adjacent rivers, the Korea Strait, volcanic material from Ulleung Island, and the Japan coast. Massive sand, bioturbated mud, homogeneous mud, and laminated mud were the dominant facies found in the core sediments from the study area. The massive sand was mainly volcanic ash from an eruption on Ulleung Island (9300 yr BP) and consisted of colorless pumiceous glass and a black scoriaceous type. The sedimentation rates on the slope, based on the Ulleung-Oki ash layer, were about 10cm/ky higher than in the basin. Other than the coarse-grain sediment, the mean size of the fine sediment dominating the bioturbated and homogeneous muds in the basin and the laminated mud on the slope was 6-10 phi. This indicates a difference in the major sedimentary process: hemipelagic sedimentation in the Ulleung Basin and mass flow deposition, such as turbidite, on the slope of the southern East Sea.