• Tribology and Lubricants
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• 제34권3호
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• pp.84-92
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• 2018

Bearings are essential for reducing vibration and wear, in order to achieve high durability and increase longevity. White metal treatment of tilting pads via centrifugal casting method has the possibility of increasing durability. However, this manufacturing method has drawbacks such as long processing time, high defect rate, and harmful health effects. Laser cladding deposition technique is a powerful method that can address these issues by decreasing the processing time and providing good adhesion. In this study, we suggest optimum conditions for laser cladding deposition that can be used in industrial applications. We deposited a soft white metal layer on SCM440 that is primarily used in shafts to minimize wear of bearing pads. During the laser deposition process, we controlled factors such as laser power, powder feed rate, and laser head speed to determine the optimum conditions. In addition, we measured the hardness using micro Vickers, and performed field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and friction tests to investigate the mechanical properties and surface characteristics for different parameters. Based on the experimental results, we suggest that laser power, powder feed rate, and laser head speed of 1.3 kW, 2.5 rpm, and 10 mm/s, respectively, constitute the optimum conditions for producing white metals using laser cladding.

• Korean Journal of Environmental Agriculture
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• 제33권1호
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• pp.57-62
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• 2014

BACKGROUND: Defoliation in grapevine cultivation is practically used to improve light environment within the canopy and thereby fruit quality. Effects of defoliation in five-year-old 'Pione' grapevine during cultivation with heating were investigated to find out optimum ratio of leaf area to fruit cluster weight (L/F). METHODS AND RESULTS: The grapevines were defoliated with berry-thinning 20 days after full bloom to provide various levels of L/F. At harvest, total leaf area values of fruit bearing branches were between 0.23 and $0.60m^2$. With increasing L/F, soluble solids and anthocyanin contents curvilinearly increased ($R^2=0.76^{**}$). At L/F over $0.6m^2/kg$, soluble solids content (SSC) leveled off. With increasing L/F, titratable acidity (TA) linearly decreased ($R^2=0.87^{**}$), but the ratio of SSC to TA linearly increased ($R^2=0.86^{**}$). Anthocyanin content was significantly correlated with SSC and the ratio of SSC to TA ($R^2=0.80^{**}$ and $0.82^{**}$, respectively). When total leaf area per fruit bearing branch was maintained $0.40m^2$, soluble solids and anthocyanin contents linearly decreased ($R^2=0.79^{**}$ and $0.85^{**}$, respectively), but TA linearly increased with increasing fruit cluster weight ($R^2=0.70^{**}$). Fruit was low in quality when the L/F was below $0.6m^2/kg$. CONCLUSION: L/F is recommended to be maintained at least $0.6m^2/kg$ in 'Pione' grapevine during cultivation with heating to produce higher-quality fruits.

• Horticultural Science & Technology
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• 제30권4호
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• pp.432-436
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• 2012

This study was conducted to determine the optimal aeration rate for mass propagation of ever-bearing strawberry by bioreactor culture. The aeration rate was treated in four levels: 0.1 vvm (air volume/medium volume/min), 0.2 vvm, 0.3 vvm, and 0.4 vvm. In 0.2 vvm conditions, shoot length was the longest at 9.03 cm in bioreactor culture, leave numbers were 40.4 ea and fresh weight was 6,106 mg. Plant growth rate at 0.2 vvm condition was faster than other treatments. In the aeration condition, 0.2 vvm was most effective to increase aerial part growth and to decrease medium consumption. As the culture periods increased, the fresh weight also increased rapidly. After six weeks of cultivation, shoots were emerged with 10.4 ea per plantlet, resulting in developing a complete plant. As a result, the bioreactor culture system for mass propagation of strawberry is required to continuously supply the air by 0.2 vvm speed and cultivate at least for six weeks.

• Journal of the Mineralogical Society of Korea
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• 제31권3호
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• pp.215-225
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• 2018

Musan iron deposit in North Korea and iron deposits in Anshan-Benxi area in China are Archean banded iron formations and included in Longgang block in Eastern block of North China Craton. Host formations of Musan iron deposit and Anshan-Benxi iron mineralized belt are Musan group and Anshan group, respectively. These groups consist of magnetite-bearing quartzite, amphibolite, schist, and migmatite. Host rock of banded iron formation in Musan deposit and Anshan-Benzi mineralized belt is magnetite-bearing quartzite. Shape of ore bodies in Musan deposit is horse's hoof due to the fold while shape of orebodies in Anshan-Benxi mineralized belt is layer. The previous studies revealed the both of banded iron formations are contemporaneously deposited during the late Archean (Musan deposit and iron deposits in Anshan-Benxi area: 2.66-2.52 Ga and 2.55-2.53 Ga, respectively). Musan deposit and iron deposits in Anshan-Benxi mineralized belt belolng to Algoma type BIFs. In conclusion, the characteristics of geology, formation ages, and deposit types of Musan deposit and Anshan-Benxi minerlized belt are very similar.

• Journal of the Korean Geotechnical Society
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• 제17권4호
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• pp.289-299
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• 2001

본 연구는 균질 및 2개층 비균질지반에서 사질토지반 상에 놓인 정방형 기초의 극한지지력과 침하에 대하여 고찰하였다. 본 연구는 얕은기초의 거동에 대한 정방형 기초의 크기, 지반 상대밀도, 기초 폭에 대한 상부층의 두께 비(H/B), 상부층 아래 경계면의 경사($\theta$) 그리고 지반강성비의 영향을 규명하기 위하여 모형실험을 수행하였다. 동일 상대밀도에서 지지력 계수($N_{{\gamma}}$)는 일정하지 않으며 기초 폭에 직접적으로 관련되며 지지력계수는 기초 폭이 증가함에 따라 감소하였다. 기초크기의 영향과 구속압력의 영향을 고려하는 Ueno 방법에 의한 극한지지력의 예측값은 고전적인 지지력 산정식보다 더 잘 일치하며 그 값은 실험값의 65% 이상으로 나타났다. $\theta$=$0^{\circ}$인 2개층 지반의 결과에 근거하여, 극한지지력에 대한 하부층 지반의 영향을 무시할 수 있는 한계 상부층 두께는 기초 폭의 2배로 결정되었다. 그러나, 73%의 상부층 상대밀도인 경우는 침하비($\delta$B) 0.05 이하에서만 이 결과가 유효하였다. 경계면이 경사진 2개층 지반의 결과에 근거하여, 상부층의 상대밀도가 느슨할수록 그리고 상부층의 두께가 클수록 극한지지력에 대한 경계면 경사의 영향은 크지 않는 것으로 나타났다. 경계면의 경사가 증가함에 따른 극한침하량의 변화는 경계면이 수평인 경우($\theta$=$0^{\circ}$)를 기준으로 0.82~1.2(상부층 $D_{r}$=73%인 경우) 그리고 0.9~1.07(상부층 $D_{r}$=50%인 경우) 정도로 나타났다.Markup Language 문서로부터 무선 마크업 언어 문서로 자동 변환된 텍스트를 인코딩하는 경우와 같이 특정한 응용 분야에서는 일반 문자열에 대한 확장 인코딩 기법을 적용할 필요가 있을 수 있다.mical etch-stop method for the etching of Si in TMAH:IPA;pyrazine solutions provides a powerful and versatile alternative process for fabricating high-yield Si micro-membranes. the RSC circle, but also to the logistics system in the SLC circle. Thus, the RSLC model can maximize combat synergy effects by integrating the RSC and the SLC. With a similar logic, this paper develops "A Revised System of Systems with Logistics (RSSL)" which combines "A New system of Systems" and logistics. These tow models proposed here help explain several issues such as logistics environment in future warfare, MOE(Measure of Effectiveness( on logistics performance, and COA(Course of Actions) for decreasing mass and increasing velocity. In particular, velocity in logistics is emphasized.

• The Korean Journal of Mycology
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• 제23권4호통권75호
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• pp.285-297
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• 1995

Ganoderan, an immunomodulating ${\beta}-glucan$ of G. lucidum, induces potent antitumor immunity in tumor-bearing mice. The present study was set up to elucidate the chemical composition and bioactivities of ganoderan obtained from the mycelial fractionation of G. lucidum IY009. Ganoderan was isolated and purified from its extracellular, cell wall and cytoplasmic sources. These ganoderans were composed mainly of glucose. The cell wall-alkali soluble-water soluble fraction (CW-AS-WS) showed the highest antitumor activity (inhibition rate of 94%) in sarcoma-bearing mice and 37% of anticomplementary activity. The CW-AS-WS fraction was found to be approximately average 20,000 dalton in aq. 0.3N NaOH solution and composed of 88% carbohydrate and 4% protein. The carbohydrate of the CW-AS-WS was composed of 74% glucose. These results indicate that the ganoderans extracted from the mycelial fractionations of G. lucidum IY009 had different chemical characteristics and showed different potentiality in antitumor and anticomplementary activity.

• Journal of Bio-Environment Control
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• 제28권1호
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• pp.28-37
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• 2019

We designed a system that can automatically collect, convey, and control cool air of $15^{\circ}C-20^{\circ}C$ containing carbon dioxide from a mushroom cultivation house to a strawberry plastic house. We recorded the temperature at various positions from July to August 2017. The average temperature of the green house during day and at night was maintained at $33^{\circ}C$ and $26^{\circ}C$, respectively. In the moveable three-tier cylindrical bed, the average temperature around root was maintained at $26^{\circ}C$ and $21^{\circ}C$ during day and at night, respectively. On the high-bench in the green house, the temperature was maintained at $32^{\circ}C$ and $30^{\circ}C$ during day and at night, respectively. The carbon dioxide concentration was maintained around 800-1,600 ppm in the mushroom cultivation system and 400-800 ppm in the strawberry plastic house. The growth characteristics of the strawberry treated with moveable three-tier cylindrical bed were significantly different from those of the untreated high-bench bed. In addition, during the summer season, moveable three-tier cylindrical bed showed more tendency to increase in normal fruit number (NFN) and to decrease in defective fruit number (DFN) compare to the high-bench bed. Therefore, the moveable three-tier cylindrical bed showed a tendency to be more than 2 times higher yields than that of the high-bench bed. It was confirmed that ever-bearing strawberry cultivars could be cultivated in green house due to the cool air supply from the mushroom cultivation system in the summer season.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제20권5호
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• pp.577-584
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• 2019

Recently, CSB(Cable-Stayed Bridge) have been attempted to be atypical forms for landscape elements in Korea. CSB with new geometry need to analyze their characteristics clearly to ensure structural safety. This study's bridge is the S-shaped curved pedestrian CSB that has a girder with S-shape plane curve and reverse triangular truss cross section, inclined independent pylon, modified Fan type main cable and vertical backstay cable. Curved CSB can have excessive lateral displacement and moment when the tension is adjusted, focusing only on longitudinal behavior, such as a straight CSB. In order to analyze the effect of the cable on the lateral behavior of bridges, the cable is divided into two groups according to the lateral displacement direction of the pylon due to tension. The influence of the combination ratio of GR1 and GR2 on the girder, bearing, pylon, and vertical anchor cable was analyzed. When the tension applied to the bridge is 1.0GR1 plus 1.0GR2, In the combination of 1.2GR1 plus 0.8GR2, the stress on the left and right upper member of the truss girder and the deviation of the both were minimized. In addition, the horizontal force of the bearing, the lateral displacement and moment of the pylon, and the tension of the vertical backstay cable also decreased. This study is expected to be used as basic data for determination of tension of CSB with similar geometry.

• Journal of Korean Society of Forest Science
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• 제100권4호
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• pp.558-564
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• 2011

This study was conducted to evaluate the effects of early revegetation by analyzing the characteristics of germination and growth of Lespedeza cyrtobotrya using boring technique in rock slopes. After making up a growing basis of approximately 20 cm depth and 10 cm diameter by using a boring machine, the surface of rock slopes was planted with vegetation-plant. The number of germinating populations by soil media was 23 in H.s, 22 in T.s, 12 in M.s, and 1 in M.g.s. The germination rate (%) by soil media was 19.2% in H.s, 18.3% in T.s, 10.0% in M.s and 0.8% in M.g.s. In monthly changes of growth rate, the aspect was northwest direction, the soil media was M.s, and the treatment was microorganism plot. The main factors affecting survivorship and growth of population were soil media and treatment plot. The interaction between each factor had a good effects in bearing ${\times}$ soil media, bearing ${\times}$ treatment plot, soil media ${\times}$ treatment plot. but, it is recommended that the mulching of vegetation plant is highly needed to help the germination of seed and growth of vegetation because of loss of seed and soil media occurred due to rainfall. Therefore, The result suggests that the revegetation technique using boring in rock slope was very efficient in respect of the early revegetation and the landscape.

• Journal of Korean Tunnelling and Underground Space Association
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• 제24권3호
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• pp.231-245
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• 2022

When vertical shafts are constructed in soft clay with low strength, there is a risk of basal heave, which causes the excavation surface to heave due to the low bearing capacity of the ground against the imbalance of earth pressure at the excavation surface. Methods of deriving a safety factor have been proposed to evaluate the stability against the basal heave. However, there are limitations in that it is difficult to accurately evaluate the heave stability because many assumptions are included in the theoretical derivation. In this study, assuming that a circular vertical shaft is constructed in soft clay, the existing safety factor equation proposed through a theoretical approach was supplemented. Bearing capacity according to the shaft geometry, inhomogeneity of the soil, and the effect of soil plug were considered theoretically and applied in a previous safety factor equation. A three-dimensional numerical analysis was conducted to simulate the occurrence of basal heave and review the supplemented equation through various case studies. Several series of case studies were conducted targeting various factors affecting heave stability. It was verified that the additionally considered characteristics were properly reflected in the supplemented equation. Furthermore, the effects of each factor constituting the safety factor equation were examined using the results of the numerical analysis performed by simulating various cases. It was confirmed that considering the undrained shear strength increment according to depth had the most significant effect on the calculation of the safety factor.