• Title/Summary/Keyword: 암석

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Seed and Germination Characteristics of Allium koreanum H.J. Choi & B.U. Oh for Effective Propagation (효과적인 번식을 위한 돌부추의 종자 및 발아 특성)

  • Hee Sung Hwang;Jeong Hun Hwang;Ji Hye Yun;So Yeong Hwang;Ji Eun Park;Hyeon Eui Oh;Sang Jun Lee;Jeong Mi Park;Seung Jae Hwang
    • Journal of Bio-Environment Control
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    • v.32 no.4
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    • pp.359-365
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    • 2023
  • Native plants are unique genetic resources that have the potential to be used as ornamental, medical, and food resources. Allium koreanum H.J. Choi & B.U. Oh is one of the native plants distributed in the coastal rocky land of Korea, which has high conservation value due to climate change and reduction of its habitat. This study was conducted to investigate the effects of temperature and hydrogen peroxide on the germination of A. koreanum. The seeds were prepared as untreated (control) or those treated with 1% hydrogen peroxide for 90 minutes (H2O2), and the treatments were placed in plant growth chambers set at 15, 20, and 25℃. Regardless of the H2O2 treatment, the germination percentage at 15℃, which was 42%, was more than two times higher than that at 20℃ and 25℃, which were 18% and 0%, respectively, 23 days after sowing. The number of days to attain 50% of the final germination percentage (T50) was the shortest at 20℃, but the mean daily germination (MDG) was the highest at 15℃. Therefore, 1% of H2O2 treatment did not have a significant effect on the germination percentage of A. koreanum, and a temperature of 15℃ was considered to be optimum to increase the germination percentage of A. koreanum. The results of this study can be used as basic research data for the germination of A. koreanum.

Seismic Wave Velocity Characteristics of the Mudeungsan Tuff under the Influence of Freeze-Thaw (동결-융해에 따른 무등산 응회암의 탄성파 속도 특성)

  • Seong-Seung Kang;Jeongdu Noh
    • The Journal of Engineering Geology
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    • v.34 no.3
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    • pp.367-379
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    • 2024
  • We analyzed the changes in the properties of the Mudeungsan tuff by conducting an artificial weathering experiment based on the climatic conditions of Mudeungsan National Park, to evaluate the long-term stability of the columnar jointing in the tuff. The climate of Mudeungsan National Park over 20 years suggests the temperature conditions for freeze-thaw are -20 to 30℃. The change in tuff properties due to weathering were estimated by measuring the elastic wave velocity, which was measured after every 40 freeze-thaw cycles. Based on the origin of the Mudeungsan tuff and fracture distribution in the tuff, the elastic wave velocity in samples from 24 locations was measured at regular intervals in the axial and radial directions. The axial elastic wave velocity of the Mudeungsan tuff is 5,187~5,367 m/s, and the radial elastic wave velocity is 4,001~5,290 m/s. As a result of 200 freeze-thaw cycles, the axial elastic wave velocity decreased by 5.53% for sample MT-1, 4.89% for MT-2, and 5.36% for MT-3. The radial elastic wave velocity decreased by 20.00% for MT-1, 17.02% for MT-2, and 19.84% for MT-3. The decrease in elastic wave velocity due to the freeze-thaw cycles is greater for low values of elastic wave velocity. For the axial elastic wave velocity, the weathering is accelerated after 120 cycles and, for the radial elastic wave velocity, weathering actively progresses from the start of the freeze-thaw cycles. In summary, for a low elastic wave velocity, experimental weathering results in a large decrease in elastic wave velocity. In addition, the Mudeungsan tuff and its columnar joints have a distinct anisotropy.

Potential Study for the Sedimentary Exhalative Pb-Zn Mineralization in Dyusembay Area, Kazakhstan (카자흐스탄 듀셈바이지역의 퇴적분기형 연-아연 광화작용에 대한 잠재력 연구)

  • No, Sang-gun;Lee, Seung-han;Park, Ki-woong;Jeong, Hyeon-guk;Yun, Ji-seong;Kim, Sun-ok;Park, Maeng-eon
    • Economic and Environmental Geology
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    • v.51 no.3
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    • pp.213-222
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    • 2018
  • Metasediment-hosted Pb-Zn mineralized zone has been found in Dyusembay of Kazakhstan. Its petrological properties, metal index, alteration index and redox-sensitivity are compared with those of SEDEX type deposit. Mineralization is developed along foliation of host rock (graphitic phyllite) and controlled by folds and faults; major ore minerals including pyrite, pyrrhotite, sphalerite, and galena are disseminated or interlayered with fine-grained quartz. The margin of the mineralized zone is metamorphosed accompanying sericite and chlorite. Hydrothermal brecciation and Pb-Zn mineralization formed in quartz-calcite stockworks are confirmed at the around of Maytyubin granitoid intrusions. The mineralization is classified into three types according to those of occurrence, paragenesis, chemical composition and isotopic characteristics. Type 1 whose fine-grained pyrite, pyrrhotite and sphalerite are formed in parallel yet discontinuous to well-developed foliations of the host rock; its geochemistry is similar to those of the earlier stage in SEDEX-type mineralization. In case of type 2, the ore minerals of which are concentrated being parallel to a foliation by regional metamorphism, and most of them associated with quartz and muscovite (${\pm}$ biotite) paragenetically. Type 3 is formed in the hydrothermal breccia zone whose ore minerals are controlled by foliation and breccia and developed in quartz ${\pm}$ calcite veins having a form such as stratification, stockwork or veinlets. Host rocks in the mineralized zone indicate homogeneous metamorphic grade and there is no specific alteration zonation. Also, all types (type 1, type 2, and type 3) represent similar REEs patterns, it can be interpreted that these are originated from a same source. Sulphides occurred in mineralized zone indicate a limited range of sulphur isotope values (type 2, ${\delta}^{34}S=-13.3{\sim}-11.7$‰; type 3, ${\delta}^{34}S=-13.9{\sim}-8.2$‰), and a result of geothermometry presents different temperature ranges: type 2($251{\pm}38^{\circ}C{\sim}277{\pm}40^{\circ}C$); type 3($360{\pm}2^{\circ}C$ to $537{\pm}29^{\circ}C$). It is estimated to be due to the effect of metamorphism and Maytyubin granitoid intrusions, respectively. In addition, ternary chart of thorium, scandium, and zircon for discrimination of tectonic setting and redox sensitivity using V/Mo values indicate that hydrothermal sediments put on reduction environment after precipitation, before being affected by metamorphism and intrusion activity. Geochemical data are plotted on a distal trend of SEDEX-type with discrimination plot using SEDEX index. As a result, petrological-geochemical properties demonstrate that Dyusembay Pb-Zn mineralized zone is comparable to distal-type of SEDEX deposit.

The Geochemical and Zircon Trace Element Characteristics of A-type Granitoids in Boziguoer, Baicheng County, Xinjiang (중국 신장 위그루자치구 바이청현 보즈구얼의 A형화강암류의 지화학 및 지르콘 미량원소특징에 대한 연구)

  • Yin, Jingwu;Liu, Chunhua;Park, Jung Hyun;Shao, Xingkun;Yang, Haitao;Xu, Haiming;Wang, Jun
    • Economic and Environmental Geology
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    • v.46 no.2
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    • pp.179-198
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    • 2013
  • The Boziguoer A-type granitoids in Baicheng County, Xinjiang, belong to the northern margin of the Tarim platform as well as the neighboring EW-oriented alkaline intrusive rocks. The rocks comprise an aegirine or arfvedsonite quartz alkali feldspar syenite, an aegirine or arfvedsonite alkali feldspar granite, and a biotite alkali feldspar syenite. The major rock-forming minerals are albite, K-feldspar, quartz, arfvedsonite, aegirine, and siderophyllite. The accessory minerals are mainly zircon, pyrochlore, thorite, fluorite, monazite, bastnaesite, xenotime, and astrophyllite. The chemical composition of the alkaline granitoids show that $SiO_2$ varies from 64.55% to 72.29% with a mean value of 67.32%, $Na_2O+K_2O$ is high (9.85~11.87%) with a mean of 11.14%, $K_2O$ is 2.39%~5.47% (mean = 4.73%), the $K_2O/Na_2O$ ratios are 0.31~0.96, $Al_2O_3$ ranges from 12.58% to 15.44%, and total $FeO^T$ is between 2.35% and 5.65%. CaO, MgO, MnO, and $TiO_2$ are low. The REE content is high and the total ${\sum}REE$ is $(263{\sim}1219){\times}10^{-6}$ (mean = $776{\times}10^{-6}$), showing LREE enrichment HREE depletion with strong negative Eu anomalies. In addition, the chondrite-normalized REE patterns of the alkaline granitoids belong to the "seagull" pattern of the right-type. The Zr content is $(113{\sim}1246){\times}10^{-6}$ (mean = $594{\times}10^{-6}$), Zr+Nb+Ce+Y is between $(478{\sim}2203){\times}10^{-6}$ with a mean of $1362{\times}10^{-6}$. Furthermore, the alkaline granitoids have high HFSE (Ga, Nb, Ta, Zr, and Hf) content and low LILE (Ba, K, and Sr) content. The Nb/Ta ratio varies from 7.23 to 32.59 (mean = 16.59) and the Zr/Hf ratio is 16.69~58.04 (mean = 36.80). The zircons are depleted in LREE and enriched in HREE. The chondrite-normalized REE patterns of the zircons are of the "seagull" pattern of the left-inclined type with strong negative Eu anomaly and without a Ce anomaly. The Boziguoer A-type granitoids share similar features with A1-type granites. The average temperature of the granitic magma was estimated at $832{\sim}839^{\circ}C$. The Boziguoer A-type granitoids show crust-mantle mixing and may have formed in an anorogenic intraplate tectonic setting under high-temperature, anhydrous, and low oxygen fugacity conditions.

The Study on the Debris Slope Landform in the Southern Taebaek Mountains (태백산맥 남부산지의 암설사면지형)

  • Jeon, Young-Gweon
    • Journal of the Korean Geographical Society
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    • v.28 no.2
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    • pp.77-98
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    • 1993
  • The intent of this study is to analyze the characteristics of distribution, patter, and deposits of the exposed debris slope landform by aerial photography interpretation, measure-ment on the topographical maps and field surveys in the southern part Taebaek mountains. It also aims to research the arrangement types of mountain slope and the landform development of debris slopes in this area. In conclusion, main observations can be summed up as follows. 1. The distribution characteristics 1)From the viewpoint of bedrocks, the distribution density of talus is high in case of the bedrock with high density of joints, sheeting structures and hard rocks, but that of the block stream is high in case of intrusive rocks with the talus line. 2)From the viewpoint of bedrocks, the distribution density of talus is high in case of the bedrock with high density of joints, sheeting structures and hard rocks, but that of the block stream is high in case of inrtusive rocks with the talus line. 2) From the viewpoint of distribution altitude, talus is mainly distributed in the 301~500 meters part above the sea level, while the block stream is distributed in the 101~300 meters part. 3) From the viewpoint of slope oriention, the distribution density of talus on the slope facing the south(S, SE, SW) is a little higher than that of talus on the slope facing the north(N, NE, NW). 2. The Pattern Characteristics 1) The tongue-shaped type among the four types is the most in number. 2) The average length of talus slope is 99 meters, especially that of talus composed of hornfels or granodiorite is longer. Foth the former is easy to make free face; the latter is easdy to produce round stones. The average length of block stream slope is 145 meters, the longest of all is one km(granodiorite). 3) The gradient of talus slope is 20~45${^\circ}$, most of them 26-30${^\croc}$; but talus composed of intrusive rocks is gentle. 4) The slope pattern of talus shows concave slope, which means readjustment of constituent debris. Some of the block stream slope patterns show concave slope at the upper slope and the lower slope, but convex slope at the middle slope; others have uneven slope. 3. The deposit characteristics 1) The average length of constituent debris is 48~172 centimeters in diameter, the sorting of debris is not bad without matrix. That of block stream is longer than that of talus; this difference of debris average diameter is funda-mentally caused by joint space of bedrocks. 2) The shape of constituent debris in talus is mainly angular, but that of the debris composed of intrusive rocks is sub-angular. The shape of constituent debris in block stream is mainly sub-roundl. 3) IN case dof talus, debris diameter is generally increasing with downward slope, but some of them are disordered and the debris diameter of the sides are larger than that of the middle part on a landform surface. In block stream, debris diameter variation is perpendicularly disordered, and the debris diameter of the middle part is generally larger than that of the sides on a landform surface. 4)The long axis orientation of debris is a not bad at the lower part of the slope in talus (only 2 of 6 talus). In block stream(2 of 3), one is good in sorting; another is not bad. The researcher thinks that the latter was caused by the collapse of constituent debris. 5) Most debris were weathered and some are secondly weathered in situ, but talus composed of fresh debris is developing. 4. The landform development of debris slopes and the arrangement types of the mountain slope 1) The formation and development period of talus is divided into two periods. The first period is formation period of talus9the last glacial period), the second period is adjustment period(postglacial age). And that of block stream is divided into three periods: the first period is production period of blocks(tertiary, interglacial period), the second formation period of block stream(the last glacial period), and the third adjustment period of block stream(postglacialage). 2) The arrangement types of mountain slope are divided into six types in this research area, which are as follows. Type I; high level convex slope-free face-talus-block stream-alluvial surface Type II: high level convex slope-free face-talus-alluvial surface Type III: free face-talus-block stream-all-uvial surface Type IV: free face-talus-alluval surface Type V: talus-alluval surface Type VI: block stream-alluvial surface Particularly, type IV id\s basic type of all; others are modified ones.

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Geochemical Equilibria and Kinetics of the Formation of Brown-Colored Suspended/Precipitated Matter in Groundwater: Suggestion to Proper Pumping and Turbidity Treatment Methods (지하수내 갈색 부유/침전 물질의 생성 반응에 관한 평형 및 반응속도론적 연구: 적정 양수 기법 및 탁도 제거 방안에 대한 제안)

  • 채기탁;윤성택;염승준;김남진;민중혁
    • Journal of the Korean Society of Groundwater Environment
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    • v.7 no.3
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    • pp.103-115
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    • 2000
  • The formation of brown-colored precipitates is one of the serious problems frequently encountered in the development and supply of groundwater in Korea, because by it the water exceeds the drinking water standard in terms of color. taste. turbidity and dissolved iron concentration and of often results in scaling problem within the water supplying system. In groundwaters from the Pajoo area, brown precipitates are typically formed in a few hours after pumping-out. In this paper we examine the process of the brown precipitates' formation using the equilibrium thermodynamic and kinetic approaches, in order to understand the origin and geochemical pathway of the generation of turbidity in groundwater. The results of this study are used to suggest not only the proper pumping technique to minimize the formation of precipitates but also the optimal design of water treatment methods to improve the water quality. The bed-rock groundwater in the Pajoo area belongs to the Ca-$HCO_3$type that was evolved through water/rock (gneiss) interaction. Based on SEM-EDS and XRD analyses, the precipitates are identified as an amorphous, Fe-bearing oxides or hydroxides. By the use of multi-step filtration with pore sizes of 6, 4, 1, 0.45 and 0.2 $\mu\textrm{m}$, the precipitates mostly fall in the colloidal size (1 to 0.45 $\mu\textrm{m}$) but are concentrated (about 81%) in the range of 1 to 6 $\mu\textrm{m}$in teams of mass (weight) distribution. Large amounts of dissolved iron were possibly originated from dissolution of clinochlore in cataclasite which contains high amounts of Fe (up to 3 wt.%). The calculation of saturation index (using a computer code PHREEQC), as well as the examination of pH-Eh stability relations, also indicate that the final precipitates are Fe-oxy-hydroxide that is formed by the change of water chemistry (mainly, oxidation) due to the exposure to oxygen during the pumping-out of Fe(II)-bearing, reduced groundwater. After pumping-out, the groundwater shows the progressive decreases of pH, DO and alkalinity with elapsed time. However, turbidity increases and then decreases with time. The decrease of dissolved Fe concentration as a function of elapsed time after pumping-out is expressed as a regression equation Fe(II)=10.l exp(-0.0009t). The oxidation reaction due to the influx of free oxygen during the pumping and storage of groundwater results in the formation of brown precipitates, which is dependent on time, $Po_2$and pH. In order to obtain drinkable water quality, therefore, the precipitates should be removed by filtering after the stepwise storage and aeration in tanks with sufficient volume for sufficient time. Particle size distribution data also suggest that step-wise filtration would be cost-effective. To minimize the scaling within wells, the continued (if possible) pumping within the optimum pumping rate is recommended because this technique will be most effective for minimizing the mixing between deep Fe(II)-rich water and shallow $O_2$-rich water. The simultaneous pumping of shallow $O_2$-rich water in different wells is also recommended.

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REE Mineralization and Geology of Chulmasan Area, Taean, Chungchungnamdo (충남 태안 철마산 일대의 지질 및 희토류 광화작용)

  • Yoo, Bong Chul
    • Journal of the Mineralogical Society of Korea
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    • v.32 no.2
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    • pp.127-143
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    • 2019
  • The geology of the Chulmasan area consists of Precambrain Sogeunri formation, granitic gneiss, foliated biotite granite, foliated mica granite, basic dyke and acidic dyke. REE mineralization in the area occurs at granitic gneiss and foliated mica granite. Minerals with minor amounts of REE and Th from granitic gneiss and foliated mica granite are zircon ($Y_2O_3$ 0.00~1.18 wt.%, $Gd_2O_3$ 0.00~0.59 wt.%, $Er_2O_3$ 0.00~0.22 wt.%, $Yb_2O_3$ 0.00~0.34 wt.%, $Lu_2O_3$ 0.00~0.48 wt.%, $ThO_2$ 0.00~0.33 wt.%), thorianite ($Nd_2O_3$ 0.00~0.24 wt.%, $Lu_2O_3$ 0.00~0.26 wt.%), berthierine ($La_2O_3$ 0.04~0.26 wt.%, $Nd_2O_3$ 0.00~0.20 wt.%, $Tb_2O_3$ 0.04~0.12 wt.%, $Dy_2O_3$ 0.17~0.26 wt.%, $Er_2O_3$ 0.33~0.44 wt.%, $Lu_2O_3$ 0.00~0.19 wt.%, $ThO_2$ 0.61~0.93 wt.%), chlorite ($La_2O_3$ 0.44~0.68 wt.%, $Ce_2O_3$ 0.12~0.13 wt.%, $Nd_2O_3$ 0.31~0.44 wt.%, $Eu_2O_3$ 0.03~0.08 wt.%, $Dy_2O_3$ 0.09~0.21 wt.%, $Ho_2O_3$ 0.04~0.14 wt.%, $Er_2O_3$ 0.18~0.32 wt.%, $Lu_2O_3$ 0.07~0.21 wt.%, $ThO_2$ 0.00~0.97 wt.%), biotite ($Nd_2O_3$ 0.02~0.08 wt.%, $Gd_2O_3$ 0.07~0.08 wt.%, $Tb_2O_3$ 0.02~0.07 wt.%, $Dy_2O_3$ 0.35~0.43 wt.%, $Ho_2O_3$ 0.15~0.26 wt.%, $Er_2O_3$ 0.24~0.28 wt.%, $Yb_2O_3$ 0.06~0.18 wt.%, $ThO_2$ 0.00~0.12 wt.%), orthoclase ($Dy_2O_3$ 0.05~0.12 wt.%, $Ho_2O_3$ 0.05~0.06 wt.%, $Er_2O_3$ 0.28 wt.%, $Yb_2O_3$ 0.06~0.12 wt.%) and plagioclase ($Ho_2O_3$ 0.01~0.03 wt.%, $Er_2O_3$ 0.10~0.27 wt.%, $ThO_2$ 0.11~0.13 wt.%). REE minerals (bastnaesite and fergusonite) were sealed fractures in mainly fledspar, mica, zircon, apatite and ilmenite. Therefore, bastnaesite and fergusonite from the Chulmasan area were formed from redissolution/reconcentration of REE-and Th-bearing minerals from granitic gneiss and foliated mica granite at late stage by several igneous activies and metamorphism.

A Study on the Natural Landscape System and Space Organization of Musudong Village's Yuhoidang Garden(Hageohwon) (무수동 유회당 원림(하거원(何去園))의 산수체계와 공간구성)

  • Shin, Sang-Sup;Kim, Hyun-Wuk;Kang, Hyun-Min
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.29 no.3
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    • pp.106-115
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    • 2011
  • This study, based on (edited in 18th century), analysed the landscape system and cultural landscape elements of Yuhoidang(Hageowon 何去園) Garden in Musu-dong, Daejeon, and the findings are as in the following. YuHoidang(Gwon Yijin 權以鎭) managed Hageowon Garden in Musu-dong, located on the southern branch of Mt. Bomun, to realize his utopia. The completion of Hageowon Garden was only possible due to his installation of a variety of facilities in family gravesite on the hill behind his house: Shimyoso(Samgeunjeongsa 三近精舍, in 1707), Naboji(納汚池, in 1713), Banhwanwon(in 1714) and expended exterior space(in 1727). With regard to the landscape system of the village, the main range of mountains consists of Mt. Daedun, Mt. Odae and Mt. Bomun. The main high mountain of the three is Mt. Bomun, where 'Blue Dragon' hill branches off on the east side(Eungbong), 'White Tiger' in the west(Cheongeun and Sajeong) and Ansan(inner mountain) in the south. The landscape system is featured by 'mountains in back and rivers in front'. The river in the south-west, with its source in Mt. Juryun is called as the 'Stream of outer perfect spot', while the 'Stream of inner perfect spot' rises from Eungbong, passing through the east part of the village into the south-western direction. Banhwanwon Garden(盤桓園) was created with the stream in the east and natural bedrocks, and its landscape elements includes Naboji, Hwalsudam, Gosudae, Sumi Waterfall, Dogyeong(path of peach trees), Odeeokdae(platform with persimmon trees), Maeryong(Japanese apricot tree), springs and observatories. An expanded version of Banhwanwon was Hageowon garden, where a series of 'water-trees-stone' including streams, four ponds, five observation platforms, three bamboo forests and Chukgyeongwon(縮景園) of an artificial hill gives the origin forest a scenic atmosphere. When it comes to semantics landscape elements, there are (1) Yuhoidang to cherish the memory of a deceased parents, (2) Naboji for family unification, (3) Gosudae to keep fidelity, (4) Odeokdae to collect virtue and wisdom, (5) Sumi Waterfall to aspire to be a man of noble character, (6) Yocheondae for auspicious life, (7) Sumanheon and Gigungjae to be in pursuit of hermitic life, (8) Hwalsudam for development of family and study, (9) Mongjeong to repay favor of ancestors, (10) Seokgasan, a symbol of secluded life, (11) Hageowon to enjoy guarding graves in retired life. The spatial composition of Hageowon was realized through (1) Yuhoidang's inside gardens(Naboji, Jucheondang, Odeokdae, Dogyeong, Back yard garden and others) (2) Sumanheon(收漫軒) Byeolup or Yuhoidang's back yard gardens (Seokyeonji, Yocheondae, Sumanheon, Baegyeongdae, Amseokwon and others) (3) Chukgyeongwon of the artificial hill(which is also the east garden of Sumanheon, being composed of Hwalsudam, Sumi Waterfall and Gasan or 12 mountaintops) (4) the scenic spots for unifying Confucianism, Buddhism and Taoism are Cemetry garden in the back hill of the village, the temple of Yeogyeongam, Sansinkak(ancestral ritual place of folk religion) and Geoeopjae(family school). On top of that, Chagyeongwon Garden(借景園) commands a panoramic distant view of nature's changing beauty through the seasons.

Studies on the Method of Ground Vegetation Establishment of Denuded Forest Land in the Mudstone Region - The Characteristics of Mudstone and Speeded-up Reforestation - (니암지대황폐림지(泥岩地帶荒廢林地)의 지피식생(地被植生) 조성방법(造成方法)에 관(關)한 연구(硏究) - 니암특성((泥岩特性)과 조기녹화(早期綠化) -)

  • Chung, In Koo
    • Journal of Korean Society of Forest Science
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    • v.19 no.1
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    • pp.1-23
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    • 1973
  • The results of ground vegetation experiment conducted at completely denuded forestland in the mudstone region are summerized as follows: On the reaults of soiling quantity the effect of soiling was observed where depth of soiling over 10 cm was practiced, and a plot where treated with 15cm soiling and without fertilizer showed poor growth and it was even worser than the plot where soiling was practiced only 1 cm in thikness but applied adequate amount of fertilizers. The depth of slits between 30cm and 40cm showed no significant difference in the effect. A plot where covered with vegetation bag showed somewhat better results in seed loss and early growth but no differences observed in the fall result over the none covered plot. And then, it is recommendable to have soiling over 10cm in thikness with slit of 30cm and 30cm in depth and to apply 30 gram of fertilizer (22;22:11, 50 gram) per slit. On various soiling materials trial there were no striking differences in the effect of soiling between weathered granite soil, wheathered tuffs soil and weathered mudstone soil. In the treatment with various green materials, a plot treated with straw mat showed a significant difference at 1 percent. The results show that weathered mudstone soil is effective to use as soiling materials and straw mat treatment was better. On forest fertilization trial, in the mudstone region where red and black pine trees already existing at a rate of 2,000-3,000 trees per hectare had applied 110kg of compound fertilizers (9:12:3 and 22:22:11) per hectare basis in terms of plant nutrient. As a result, the difference in effect between the compound fertilizers was not found however the leaf color and leaf length of the fertilizer added plot showed darker and longer at 30 percent over the no fertilizer received plot. Compound fertilizers, 14:37:12 and 9:12:3 were applied to alder trees at a rate of 20 gram and 40 gram per tree in terms of plant nutrient and a remarkable growth accelerantion was observed where 40 grams of plant nutrient applied. The effect difference between the compound fertilizers was not found. On investigation of tree root elongation, forty years old red pine trees showed only 15cm tap root elongation through mudstone while black pine had 23 cm tap root elongation. The total length of supporting root elongtion of red and black pines showed 20 and 13 meters, respectively. The tap roots of Black locusts were not able to elongate through mudstone, however, the supporting roots tended to develop to the underneath of pine tree where some moisture content is available. Black locusts And grown on the residual soil of mudstone normally die between 8 to 10 years. The red pine trees show flat in tree shape while black pine had triangle in the shape. With the results it can be said that in an artificial reforestation in denuded forest land of the mudstone region the adequate slit and enough amount of fertiliizer application must be provided for the succesful performance of the program. On integrated experimental results of 1972. for the establishment of ground vegetation on the completely denuded forest land in mudstone region, soiling could be effectively practiced with weathered mudstone soil and it would not specially necessiate to have either weathered granite or tuffssoil for the soiling. And the soiling depth should be more than 10 cm in thickness. Among green materials used the straw mat proved to be the most effective reatment. Three major factors which enable to establish ground vegetation by the shortest period of time: A. Physical improvement of soil is necessary to breakdown of the horizontal cracks sushas Slit, contour line plot, seeding hole and etc., and soiling with weathered mudstone soil. B. Chemical improvement of soil: is needed sufficient amount of fertilizer application 300~400kg ha, $N+P_2O_5+K_2O$), and increased production of ground covering and expedite resolution of the vegetation (ground vegetation, fallen leaves and twigs). C. Complete establishment of the basic structure for the erosion control (Prevention of surface soil erosion)

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Dynamical Study on the Blasting with One-Free-Face to Utilize AN-FO Explosives (초유폭약류(硝油爆藥類)를 활용(活用)한 단일자유면발파(單一自由面發破)의 역학적(力學的) 연구(硏究))

  • Huh, Ginn
    • Economic and Environmental Geology
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    • v.5 no.4
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    • pp.187-209
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    • 1972
  • Drilling position is one of the most important factors affecting on the blasting effects. There has been many reports on several blasting factors of burn-cut by Messrs. Brown and Cook, but in this study the author tried to compare drilling positions of burn-cut to pyramid-cut, and also to correlate burn-cut effects of drilling patterns, not being dealt by Prof. Ito in his theory, which emphasized on dynamical stress analysis between explosion and free face. According to former theories, there break out additional tensile stress reflected at the free face supplemented to primary compressive stress on the blasting with one-free-face. But with these experimented new drilling patterns of burn-cut, more free faces and nearer distance of each drilling holes make blasting effects greater than any other methods. To promote the above explosive effect rationary, it has to be considered two important categories under-mentioned. First, unloaded hole in the key holes should be drilled in wider diameter possibly so that it breaks out greater stress relief. Second, key holes possibly should have closer distances each other to result clean blasting. These two important factors derived from experiments with, theories of that the larger the dia of the unloaded hole, it can be allowed wider secondary free faces and closes distances of each holes make more developed stress relief, between loaded and unloaded holes. It was suggested that most ideal distance between holes is about 4 clearance in U. S. A., but the author, according to the experiments, it results that the less distance allow, the more effective blasting with increased broken rock volume and longer drifted length can be accomplished. Developed large hole burn-cut method aimed to increase drifting length technically under the above considerations, and progressive success resulted to achieve maximum 7 blasting cycles per day with 3.1m drifting length per cycle. This achievement originated high-speed-drifting works, and it was also proven that application of Metallic AN-FO on large hole burn-cut method overcomes resistance of one-free-face. AN-FO which was favored with low price and safety handling is the mixture of the fertilizer or industrial Ammonium-Nitrate and fuel oil, and it is also experienced that it shows insensible property before the initiation, but once it is initiated by the booster, it has equal explosive power of Ammonium Nitrate Explosives (ANE). There was many reports about AN-FO. On AN-FO mixing ratio, according to these experiments, prowdered AN-FO, 93.5 : 6.5 and prilled AN-FO 94 : 6, are the best ratios. Detonation, shock, and friction sensities are all more insensitive than any other explosives. Residual gas is not toxic, too. On initation and propagation of the detonation test, prilled AN-FO is more effective than powered AN-FO. AN-FO has the best explosion power at 7 days elapsed after it has mixed. While AN-FO was used at open pit in past years prior to other conditions, the author developed new improved explosives, Metallic AN-FO and Underwater explosive, based on the experiments of these fundmental characteristics by study on its usage utilizing AN-FO. Metallic AN-FO is the mixture of AN-FO and Al, Fe-Si powder, and Underwater explosive is made from usual explosive and AN-FO. The explanations about them are described in the other paper. In this study, it is confirmed that the blasting effects of utilizing AN-FO explosives are very good.

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