• KSCE Journal of Civil and Environmental Engineering Research
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• v.8 no.1
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• pp.33-40
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• 1988

The new technique has been used to determine the soil-reinforcement interaction. The testing apparatus is essentially a triaxial cell fitted with the capability to house a hollow cylinderical sample. A hollow cylinderical sand specimen with a concentrical layer of reinfarcing material sandwitched in the middle is used in this investigation. The reinforcement is fastened at the base. The hollow specimen can be viewed as a "unit sheet" of a soil-reinforcement composite system of infinite horizontal extent. Axial load as well as inner and outer chamber pressures can be applied to perform a test. The specimen is first subjected to an isotropic stress state corresponding to the overburden pressure. Next, an extension test by reducing the axial load is carried out. The specimen is "loaded" to failure by either the breakage of reinforcing material (tensile failure) or slippage which takes place at the soil-reinforcement interface (i.e. the overcoming of the bonding capacity). Since the reinforcement is fastened at its lower end to the base, any tendency of relative movement between the reinforcement and the sand during an extension test can induce tensile force in the reinforcement thus forming a "reversed pull-out" test condition. Preliminary test results have demonstrated positively of the new approach to test the soil-reinforcement interaction. Reinforcing elements of different extensibility were used to study the deformbility of reinforced soil. Furthermore, both the breakage and the pull-out modes of failure were observed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.8 s.227
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• pp.895-901
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• 2004

Single-phase convection and nucleate boiling heat transfer were locally investigated for confined planar water jets. The detailed distributions of the wall temperature and the convection coefficient as well as the typical boiling curves were discussed. The curve for the single-phase convection indicated the developing laminar boundary layer, accompanied by monotonic increase of the wall temperature in the stream direction. Boiling was initiated from the furthest downstream as heat flux increased. Heat transfer variation according to the streamwise location was reduced as heat flux increased enough to create the vigorous nucleate boiling. Velocity effects were considered for the confined free-surface jet. Higher velocity of the jet caused the boiling incipient to be delayed more. The transition to turbulence precipitated by the bubble-induced disturbance was obvious only for the highest velocity, which enabled the boiling incipient to start in the middle of the heated surface, rather than the furthest downstream as was the case of the moderate and low velocities. The temperature at offset line were somewhat tower than those at the centerline for single-phase convection and partial boiling, and these differences were reduced as the nucleate boiling developed. For the region prior to transition, the convection coefficient distributions were similar in both cases while the temperatures were somewhat lower in the submerged jet. For single-phase convection, transition was initiated at $x/W{\cong}2.5$ and completed soon for the submerged jet, but the onset of transition was retarded to the distance at $x/W{\cong}6$ for the fee-surface jet.

• Horticultural Science & Technology
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• v.17 no.4
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• pp.485-488
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• 1999

This study was conducted to obtain a basic information on the structural and histological characteristics of Gerbera hybrida Hort. leaf injured by american serpentine leafminer (ASL), Liriomyza trifolii, by using light and scanning electron microscope (SEM). Based on the anatomical observation of leaf blade injured by L. trifolii, the injury process could be divided into three stages. In the initial stage, the punctured tiny holes where ASL layed eggs after suction in the upperside of leaf were observed in the palisade parenchyma. In the middle stage, the hatched larvae made mines in the palisade parenchyma only. In the final stage, the mature larvae grew up making the mines bigger, and just before going out from the epidermis, it injured the inside of leaf containing one layer palisade parenchyma and two layers of spongy parenchyma.

• Korean Journal of Acupuncture
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• v.29 no.2
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• pp.239-249
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• 2012

Objectives : This study was investigated to observe Foot Soeum Meridian Muscle in human. Methods : In order to expose components related to Foot Soeum Meridian Muscle, cadaver was dissected in the order of their depth; being respectively divided into superficial, middle, and deep layer. Results : Anatomical components related to Foot Soeum Meridian Muscle in human are composed of muscles such as flexor digitorum brevis tendon, abductor hallucis muscle, psoas major m., erector spinae m., and flexor retinaculum, fascia such as plantar aoneurosis, ligament such as sacrotuberal ligament, sacrospinous lig., nuchal lig., nerves such as plantar cut. br. of med. plantar nerve, med. crural cut. br. of saphenous n., br. of tibial n., post. femoral cut. n., spinal n.(dorsal rami of C4-6, T7-12, L1-3, and S1-3), and autonomic nervous system(sacral plexus, pelvic splanchnic n., etc.), and etc. Conclusions : This study shows comparative differences from established studies on anatomical components related to Foot Soeum Meridian Muscle, and the methodical aspects of analytic process. In addition, Foot Soeum Meridian Muscle in human is a comprehensive concept including the relevant nerves, but it remains questionable.

• Journal of Biosystems Engineering
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• v.21 no.4
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• pp.429-435
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• 1996

A wind tunnel consisting of two air flow conditioners with polycarbonate pipes, a plant growth room, a suction fan and fan controller, and fluorescent lamps, was designed to investigate the interactions between the growth of plug seedlings under artificial light and their Physical environments. Light transmissivities in the plant growth room based on the photosynthetic photon flux density and photosynthetically active radiation was appeared to be 96.3% and 96.8%, respectively. Measurement showed a uniformity in the vertical profiles of air current speed at the middle and rear regions of plug trays in wind tunnel. This result indicated that the development of a wind tunnel based on the design criteria of the American Society of Mechanical Engineers was adequate. Air current speed inside the plug stand was significantly decreased due to the resistance by the leaves of plug seedlings and boundary layer developed over and below the plug stand. Driving force to facilitate the diffusion of gas inside the plug stand might be regarded as extremely low. Aerodynamic characteristics above the plug stand under artificial light were investigated. As the air current speed increased, zero plane displacement decreased but roughness length and frictional velocity increased. Zero plane displacement linearly increased with the average height of plug seedlings. The wind tunnel developed in this study would be useful to investigate the effects of air current speed on the microclimate over and inside the plug stand and to collect basic data for a large-scale plug production under artificial light in a semi-closed ecosystem.

• Tunnel and Underground Space
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• v.22 no.3
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• pp.221-225
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• 2012

Magnesium is one of the light weight materials, which can improve fuel economy and reduce emissions in automotive industry. Recently, magnesium alloys have gained considerable attention due to good mechanical properties. In this work, we have performed an explosive welding using the magnesium alloys (AZ31) and stainless steel (SUS 304). As a result, SUS304/AZ31 were successfully combined each other; however, a resolidified interlayer was observed at the point of welded layer. To reduce the resolidified interlayer, we have changed the thickness (0.5 mm and 1 mm) of stainless steel, distance (45 mm and 60 mm) between explosive and the center of materials and initial angle ($20^{\circ}$ and $30^{\circ}$) of explosive. In the case of the thickness 0.5 mm and angle of $30^{\circ}$, the resolidfied interlayer was not observed due to the increase of distance from the explosive. To accurately estimate the resolidified interlayer, electron probe micro-analyzer (EPMA) method and hardness were used. For the EPMA analysis, mixed materials were confirmed at the resolidified interlayer, and the measurement exhibited the middle value compared with the AZ31 and SUS304.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.1
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• pp.126-137
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• 2011

This study simulate three-dimensional ocean circulation patterns using the EFDC model in the Kwangyang Bay and Jinju Bay, considering tide, water temperature and salinity. The numerical model results were verified using observed data. The model results well reproduced the observed data. As a result, ocean circulation patterns in the study area show convergence and divergence in the middle area of Noryang waterway and Daebang waterway, the residual flow patterns show typical two-layer circulation. According to the change of the density stratification in the Kwangyang Bay and Jinju Bay, the effect of fresh water is dominant in study area. In the case of Jinju Bay, although it is strongly influenced by the Namgang fresh water, also it is affected by Seomjin River when there is no discharge by Namgang Dam. On the other hand, the stratification of the Kwangyang Bay is relatively enhanced by the discharge of Namgang Dam.

• Korean Journal of Oriental Medicine
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• v.16 no.3
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• pp.123-126
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• 2010

Objective : There are controversial opinions on the location of PC8 (Nogung). The one is to localize the point between the 2nd and 3rd metacarpal bone, the other is to localize the point between the 3rd and 4th metacarpal bone. The study was performed to provide an experimental evidence to standardize the location of PC8 point. Methods : We employed 30 healthy adults evenly in sex. To identify the location of PC8 in the hand, we took X-ray photograph in both hands of participants. Thin layer of leads were pasted on to PC7 and tip of middle finger prior to take X-ray photograph. The line connecting two points corresponding to the leads in X-ray film was read by a radiologist to decide that the line passes which side between the 2nd metacarpal space and the 3rd one. Results and Conclusions: The line passed the 3rd metacarpal space in 49 cases out of 60 hands (82 %). Data suggest that PC8 could be localized at the point between the 3rd and 4th metacarpal bone.

• Journal of the Korean Geotechnical Society
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• v.18 no.1
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• pp.133-140
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• 2002

Phosphogypsum is a by-product from the phosphoric acid process for manufacturing fertilizers. It consists mainly of $(CaSO_4.2H_2O)$ and contains some impurities such as$(P_2O_5)$, 불소$(F_-)$, and organic substances. The annual world production of this material is up to 150 million tons and is up to 1.57 million tons in Korea. Therefore studies describe application of phosphogypsum to daily and middle cover materials in landfill. For this Purpose, experiments were performed to evaluate the engineering properties of the material by sieve analysis, specific gravity, consistency of soil, compaction, CBR, permeability, mi environmental characteristics of leaching test, reactor test. The results of this study are as follows : The mixing and layer conditions of CBR value are 6.2~6.3%, coefficient of permeability is $\alpha$$\times10_{-5}~10_{-6}cm/sec$. And leaching test results are far below than those of regulatory requirement of Waste Management Act, Soil Environment Preservation Act in Korea and RCRA in USA. Therefore phosphogypsum can be used as daily and intermediate cover materials in landfill.

• Korean Journal of Environmental Agriculture
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• v.16 no.1
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• pp.44-47
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• 1997

The change in microbial flora has been studied through dwelling house composting by the composter with double layer walls. The results are summarized as followes. 1. Mesophilic bacteria increased and decreased mildly, thermophilic bacteria showed a tendency to decrease except for spring, and the number of mesophilic bacteria and thermophilic bacteria had a tendency to increase and decrease simultaneously. 2. The number of mesophilic actinomycetes were increased at the early stage of compositing in winter, mildly decreased in spring and slightly decreased in summer, and the number of thermophilic actinomycetes were decreased at the early stage of composting. 3. The decrease in the number of mesophilic fungi was observed at the middle stage in summer, but the mild increase was observed in spring and winter. The number of thermophilic fungi was generally decreased. 4. Ammonia oxidizer and nitrite oxidizer were observed in this field composting much more than in the other composting experiments.