• 자원환경지질
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• 제18권2호
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• pp.139-150
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• 1985

Skarn at the Dielette formed largely in calc-silicate hornfels at the contact with the Flamanville granite. The skarn consists mainly of garnet and pyroxene, and less frequently vesuvianite. Traversing toward calc-silicate hornfels wall rock from a central zone of the skarn, the general sequence of formation of mineral assemblages is: (1) dark brown garnet (2) pale brown garnet-vesuvianite-pyroxene, and (3) pyroxene-prehnite-scapolite-wollastonite envelopes (designated as transition zone) developed between skarn and calc-silicate hornfels. The central zone of the skarn consists mainly of dark brown garnets (garnet I) that contain little or no pyroxene. The pale brown garnet (garnet II) is associated with pyroxene and vesuvianite. The sequence of these garnets results from the zonal growth outward. There is an abrupt discontinuity in composition between garnet I formed in early stage and garnet II in late stage, while each garnet shows relatively uniform composition. At the zone in contact with the granite, the iron contents of garnets decrease toward the marginal zone of the skarn, from an average value of 36 mole % andradite in garnet I to 18 mole % andradite in garnet II. At the zone distant from the granite, the andradite component decreases from 28 mole % in garnet 1 to 19 mole % in garnet II. The variation of the iron contents of pyroxenes is also similar to that of garnets. The sharp discontinuity in composition of garnets and pyroxenes suggests that the skarn of study area was formed by infiltration metasomatic process. The results of the analyses of mineral assemblages of the transition zone by chemical potential diagrams suggest that the transition zone was made by the diffusion of the elements Ca, K and Fe from the skarn to the calc-silicate hornfels contact zone. The estimated temperatures and $Xco_2$ for the formation of the transition zone show $300^{\circ}C$$440^{\circ}C$ and $0.07{\pm}0.05<Xco_2<0.02{\pm}0.01$ at 1 Kb respectively.

• 대한원격탐사학회지
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• 제39권2호
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• pp.129-142
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• 2023

본 연구는 2018년 4월부터 2022년 4월까지 Orbiting Carbon Observatory-2/3의 건조공기 이산화탄소 몰분율(column-averaged carbon dioxide dry-air mole fraction, XCO₂) 자료와 TROPOspheric monitoring instrument의 일산화탄소(carbon monoxide, CO) 및 이산화질소(nitrogen dioxide, NO₂) 연직컬럼농도(본 연구에서 XCO, XNO₂로 명명) 자료를 활용하여 한국과 중국의 도시 및 권역에 대해 CO와 CO₂, CO와 NO₂의 비율을 분석하고, 사회경제적 지표(인구, 차량 등록 대수, 지역내총생산)와 비율의 관계, 한국과 중국에서의 특성 차이를 제시하였다. 먼저 CO₂, CO 그리고 NO₂ 세 기체상 물질의 대기 중 체류시간 차이로 CO₂, CO는 배경값과 추세선을 제거한 ΔXCO₂, ΔXCO로 분석하였다. 지역별로 세 값을 비교한 결과 ΔXCO, ΔXCO₂는 중국 지역이 XNO₂는 한국 지역이 상대적으로 높은 값을 보였으며, 두 값의 비율(ΔXCO/ΔXCO₂, ΔXCO/XNO₂) 모두 한국보다 중국에서 높은 것으로 나타났다. ΔXCO/ΔXCO₂, ΔXCO/XNO₂와 사회경제적 지표는 양의 상관관계를 보였으며, 이는 도시 규모가 크고 경제활동이 활발할수록 대기오염기체 및 온실기체의 농도가 높다는 점을 시사한다. 한국과 중국의 비율 특성 차이를 분석하기 위해 두 나라의 지역별로 분석한 ΔXCO와 ΔXCO₂ 관계는 한국은 음의 관계성을 중국은 양의 관계성을 나타냈다. ΔXCO와 XNO₂의 상관성을 여름과 겨울에 대해 각각 살펴본 결과, 한국은 계절에 따른 ΔXCO 증감이 크지 않은 것에 비해 중국은 북동부 지역을 중심으로 계절에 따른 ΔXCO와 XNO₂의 증감이 크게 나타나며 관계성의 차이를 보였다. 이는 온실기체와 대기오염기체의 비율을 분석할 때, 계절 변동성 및 국가별 배출 특성을 감안해야 함을 시사한다.

• 자원환경지질
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• 제16권1호
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• pp.1-10
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• 1983

The Yeonhwa (I, II) and Keodo mines, neighboring in the middle part of the Taebaegsan mineral belt, contain three distinct classes of skarn deposits: the zinc-lead skarn at Yeonhwa (I, II), the iron skarn at Keodo south (Jangsan orebodies), and the copper skarn at Keodo north (78 orebodies). The present study characterizes the three classes of skarn deposits mainly in terms of skarn/ore associations examined from chemical compositional point of view, and applies existing quantitative phase diagrams to some pertinent mineral assemblages in these mines. At Yeonhwa I the Wolam I orebody shows a vertical variation in skarn minerals ranging from clinopyroxene/garnet zone on the lower levels through clinopyroxene (without garnet) zone on the intermediate levels, and finally to rhodochrosite veins on the upper levels and surface. Ore minerals, sphalerite and galena, associate most closely with the intermediate clinopyroxene zone. At Keodo, the Jangsan iron skarn hosted in quartz monzodiolite as a typical endoskarn, shows a skarn zoning, from center of orebody to outer side, magnetite zone, magnetite/garnet zone, garnet clinopyroxene zone, and clinopyroxene/epidote/plagioclase zone. The 78 copper skarn in the Hwajeol limestone indicates a zoning, from quartz porphyry side toward limestone side, orthoclase/epidote zone, epidote/clinopyroxene zone, and clinopyroxene/garnet zone; chalcopyrite and other copper sulfides tend to be in clinopyroxene/garnet zone. Mioroprobe analyses of clinopyroxenes and garnets from the various skarn zones mentioned above revealed that the Yeonhwa zinc/lead skarns are characterized by johansenitic clinopyroxene (Hd 25-78, Jo 15-23) and manganoan andraditic garnet (Ad 13-97, Sp 1-24), whereas the Jangsan iron skarn at Keodo by Mn-poor diopsidic clinopyroxene (Di 78-93, Jo 0.2-1.0) and Mn-poor grossularitic grandite (Gr 65-77, Sp 0.5-1.0). The 78 copper skarn at Keodo is characterized by Mn-poor diopsidic-salite (Di 66-91, Jo 0.2-1.1) and Mn-poor andraditic grandite(Ad 40-74, Sp 0.5-1.1). The compositional charateristics of iron, copper, and zinc-lead skarns in the Yeonhwa-Keodo mines are in good correlations with those of the foreign counterparts. Compiling a $T-XCO_2$ phase diagram for the Jangsan endoskarns, a potential upper limit of temperature of the main stage of skarn formation is estimated to be about $530^{\circ}C$, and a lower limit to be $400^{\circ}C$ or below assuming $XCO_2=0.05$ at P total=1kb. Applying a published log $fS_2$-log $fo_2$ diagram to the Keodo 78 and Yeonhwa exoskarns, it is revealed that copper sulfides and zinc-lead sulfides do not co-exist stably below log $fS_2=-4$ and log $fO_2=-23$ at $T=400^{\circ}C$ and ${\times}CO=1$ atm.

• 자원리싸이클링
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• 제7권4호
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• pp.22-26
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• 1998

M-type Ba-ferrite(${BaFe}_{12-2X}{Ti}_{X}{Co}_{X}{O}_{19}$)의 ${Fe}^{3+}$ 이온 대신에 A이온의 위치에는 비자성 이온인 ${Ti}^{4+}$을, Me이온은 위치에는 ${Co}^{2+}$을 치환시켜 치환량 x의 변화에 따른 결정자기이방성 감소를 관찰하고, 고주파 대역에서 전파흡수재로서 사용가능 여부를 실험하였다. 치환결과 보자력은 결정자기이방성이 감소함에 따라 급격히 감소하는 경향을 보였으며, 포화자화값은 ${Fe}^{3+}$이온 대신에 비자성인 ${Ti}^{4+}$이온이 치환됨에 따라 거의 직선적으로 감소하였다. 특히, 치환량이 1.2일 때 보자력은 185 Oe로 가장 낮았고, 포화자화는 43.5emu/g의 값을 나타내었다. 반사손실을 계산한 결가 Ti-Co 치환량 0.8일 때 2mm흡수체의 경우 10~16㎓의 대역에서 반사손실-10㏈(90%흡수)이하였으며, 감쇠능의 측정결과 12~16㎓의 대역에서 20㏈(99% 감쇠)로 12~16㎓의 고주파 대역에서 전파흡수재로 사용이 가능함을 예측할 수 있었다.

• 대한물리의학회지
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• 제15권2호
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• pp.11-21
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• 2020

PURPOSE: This study examined the effects of posture improvement exercise using virtual reality programs on the posture and balance of patients with forward head postures. METHODS: Thirty men and women in their 20 s, who had a forward head posture, were divided randomly into a group with posture correction exercise and a group with posture correction exercise combined with virtual reality programs. The posture correction exercise was composed of squats, XCO training, and chin-tuck exercise. In contrast, exercise with virtual reality games involved the Hot Squat, Climbey, and Baskhead programs while wearing a headset. Both groups performed the exercises 15 min a day, three times per week, for four weeks. The balance ability, distance between the acromion and earlobe, and neck joint range of motion were assessed before and after the exercises. RESULTS: Both groups showed significant reductions in the distance between the acromion and the earlobe, along with significant improvements in the range of joint motion. The group that performed the virtual reality exercises showed a significant increase in the limit of stability. Both groups showed a significant decrease in the sway length. In contrast, the group given the virtual reality exercises showed a significant reduction in the sway speed while standing with their eyes closed. CONCLUSION: Exercise applying virtual reality programs can be used in clinical and home programs to correct the postures of individuals with a forward head posture because they can trigger interest in inducing active participation.

• 한국광물학회지
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• 제8권2호
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• pp.57-72
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• 1995

춘천 지역 선캠브리아기의 구봉산층군 내의 백운석질 대리암에는 광역변성작용의 산물로서 조립질의 투각섬석이 주된 규산염 광물상을 이루며 산출된다. 이들은 배태 층준과 원암의 조성에 따라 두 가지 유형으로 구분된다. : (1) 투각섬석(흑회색)+방해석+백운석+활석, (2)투각섬석(백색)+금운모+백운석+방해석+K-장석, 백색의 투각섬석이 흑회색형보다 상대적으로 높은 Al과 알칼리 함유도를 보이지만, 전반적으로 모두 Mg-단종에 가까운 화학 조성을 갖는다. 투각섬석들이 격자 구조상의 결함 구조를 갖지 않는데 비해서, 금운모는 1M 구조형을 이루고 저면 격자 간격상에 녹니석 단위의 빈번한 개재에 의한 격자상의 구조적 결함이 흔히 관찰된다.방해석-백운석 지온계에 대한 연구와 TWEEQU 프로그램을 이용한 상평형도 작성을 통해서, 투각섬석들은 500~$600^{\circ}C$의 온도 범위, 8kb 정도의 압력 및 Xco2=0.2~0.5 조건에서 생성된 것으로 해석하였다. 이 지역의 투각섬석은 위와 같은 조건에서 지속적으로 평형 상태가 유지되고 상안정도가 증대되므로서, (1) 투휘석을 수반하지 않고, (2) 격자 구조상의 결합을 갖지 않는, (3) 자형의 큰 결정을 이루게 된 것으로 해석된다.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.635-636
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• 2006

In this study, the diffusion behaviors of C and Co in liquid phase sintering of WC-Co system were investigated whether these two components diffused in the same direction in case of having opposite gradient each other with not being $\eta$ phase. The green compacts with controlled compositions in not being of $\eta$ phase and gradient composition which one is WC-5Co-1.2%C, the other is WC-XCo-0.2%C (where X = 5, 10, 15, 20, 25) were sintered at $1350^{\circ}C$ and $1400^{\circ}C$ and then the diffusion behaviors of C and Co were investigated by analyses of compositional change, also determined for microstructure and microhardness. Also, same testing was carried out on the specimens with dual layers sintered in upright and reverse positions to evaluate the effect of gravity on the diffusion in liquid Co. From the results of this study, we can find the fact that the direction of diffusion for C and Co in WC-Co system during liquid phase sintering was different and the effect of gravity for the liquid was insignificant. Also other physical properties were changed on the diffusion of elements.

• 한국운동역학회지
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• 제21권3호
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• pp.309-315
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• 2011

The purpose of this study was to evaluate the effect of asymmetric muscle force in lower extremity on dynamic balance during walking. Sixteen elementary students(age: 12.3${\pm}$0.7 yrs, height: 149.4${\pm}$9.7 cm, weight 40.6${\pm}$7.8 kg) who have no musculoskeletal disorder were recruited as the subjects. Temporal parameters, M-L inclination angle of XCoM-CoP, M-L and A-P CoP, loading rate, and decay rate were determined for each trial. For each dependent variable, a independent-sample t-test was performed to test if significant difference existed between each conditions(p<.05). The displacement of antero-posterior COP during RTO-LHC1 in SG was siginificantly smaller than corresponding value in AG. In contrast, the displacement of medio-lateral COP during RTO-LHC1 in SG was greater than those of AG. It seems that imbalance of muscle force may result in increasing the medio-lateral stance in order to minimize the instability. We found that the asymmetric muscle force in the lower extremity may be a reason for the awkward control of impact force.

• 한국연소학회지
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• 제21권1호
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• pp.38-45
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• 2016

Flame characteristics and NO emission behavior in $CH_4$/air-air premixed counterflow flames with applying FIR and FGR with $CO_2$ and $H_2O$ were investigated numerically by varying the ratios of FIR and FGR as well as global strain rate. Chemical effects of added $CO_2$ and $H_2O$ via FIR and FGR were analyzed through comparing flame characteristics and NO behaviors from real species($CO_2$ and $H_2O$) with those from their artificial species($XCO_2$ and $XH_2O$) which have the same thermochemical, radiative, and transport properties to those for the real species. The results showed that flame temperature and NO emission with FIR varied much more sensitively than that with FGR. Those varied little irrespective of adding $CO_2$, $H_2O$, and their artificial species to the fuel stream via FIR. However, Those were varied complicatedly by chemical effects of added $CO_2$ and $H_2O$ via FGR. Detailed analyses for them were made and discussed.

• 자원환경지질
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• 제20권3호
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• pp.169-177
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• 1987

The Manjang copper magnetite-fluorite orebodies are imbedded within the limestone beds of the Hwajonri Formation. The ore deposits are characterized by magnetite-fluorite bearing skarn orebody in the west orebody and copper sulfide veins of the central and main orebodies. This study includes fluid inclusion geothermometry, salinity analysis, stable isotope analysis, and application of phase rule to mineral associations in skarn ore. Ore minerals are closely associated with the skarn silicates such as garnet, wollastonite and epidote. Magnetite and fluorite are remarkable in the west orebody whereas chalcopyrite is dominate in the central and main orebodies where pyrite and pyrrhotite also appear as sulfide gangues. Homogenization temperature and salinity of fluid inclusions are measured ranging between $240^{\circ}C$ and $350^{\circ}C$, 6.3~12.9 wt. percent in quartz and $220^{\circ}C$ and $350^{\circ}C$, 8.5~9.9wt. percent in fluorite, respectively. This indicates that the filling temperature and salinity are higher in quartz than in fluorite with the tendency of both to be linearly decreased suggesting an attribution of meteoric water to the mineralization. $T-fo_2$ diagram in the Ca-Fe-Si system at 1 kb and $Xco_2$=0.02 shows that the mineral assemblages with decreasing temperature are andradite-hedenbergite-calcite, hedenbergite-andradite-quartz, magnetite-andradite-quartz, and magnetite-quartz-calcite, indicating that magnetite crystallizes mostly late skarn stage at lower temperature. According to the carbon and oxygen isotopic values of the host limestone and calcite in ores, the sourec of carbon might be mixture of host limestone and deep seated carbons. Sulfur isotope data imply that ore fluids be relatively homogeneous in sulfur isotopic composition, mainly derived from igneous source.