• Korean Journal of Mineralogy and Petrology
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• v.33 no.2
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• pp.129-141
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• 2020

The Mogok metamorphic belt is a highland area mainly consisting of Archean crystalline rocks, where many ruby mines were distributed in the past, and jewelry has been identified in its alluvium as placer deposit. Minerals that are usually identified with ruby include spinel, garnet, and rubellite. The conglomerates that form the alluvium in which jewelry is found mainly consist of gneiss and clastic pegmatites. In Singu, Mogok, and Momeik areas, a number of pegmatites containing jewelry are distributed in the intrusions of Mogok metamorphic rocks, diorites, and granites. In Singu pegmatites, rubellite, goshenite, and blue and violet apatite occur as gems. In Momeik pegmatites, mushroom-type rubellite, petalite, hambergite, pollucite, and aquamarine can be found. In Mogok pegmatites, topaz, aquamarine, goshenite, and herderite occur are present.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.14 no.4
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• pp.191-198
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• 2019

The purpose of this study is to explain the bootstrapping method to understand the process of overcoming the difficulties experienced by the limited resources of the initial start-up, through the example of Black Ruby Studio. Most nascent start-ups have constrained resources. This problem is a subject that is constantly being repeated in entrepreneurship research. Despite these problems, there are relatively few studies detailing the process of overcoming the initial difficulties of start-up. Bootstrapping is described as a way to reduce external inflows, reduce risk, and resolve funding issues internally. Many start-ups initially rely on bootstrapping as a way to solving scarce funds and limited resources. Therefore, this study reviewed the prior literatures in bootstrapping, and used 32 detailed item bootstrapping methods suggested in Winborg & Landstrom(2001) on bootstrapping in order to understand bootstrapping concept of start-up. This study gives insightful implication to prospective founders by using the bootstrapping method for survival of start-up and the process of overcoming the difficulties in the start-up.

• Food Science and Preservation
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• v.30 no.1
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• pp.78-87
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• 2023

This study was conducted to evaluate the effect of different 1-methylcyclopropene (1-MCP) concentrations on fruit quality of small-sized RubyS apples during cold storage. After harvesting, the fruits were treated with 1-MCP at 0.5 or 1 µL/L concentrations and, subsequently, stored at 0℃ for 6 months. After 6 months, the flesh firmness of untreated fruits, which was 85.4 N at harvest, had gradually decreased to 46.5 N; however, that of 1-MCP-treated fruits was maintained at 59.1 and 59.5 N. Titratable acidity (TA) of untreated fruits had also decreased from 0.42 to 0.24%, whereas that of 1-MCP-treated fruits was maintained at 0.26 and 0.27%. Soluble solids content (SSC) did not differ in all fruits. However, the 1-MCP-treated fruits had lower levels of SSC/TA ratio than untreated fruits. Moreover, after 6 months, the ethylene production had increased to 47.0 µL/kg/h in the untreated fruits, whereas 1-MCP blocked the ethylene production at 1.4 and 1.7 µL/kg/h. The weight loss and peel color variables remained unaffected by 1-MCP treatments. Thus, these results indicated that, for RubyS apples, the storability was only 2 months at 0℃ without treatment, which can be extended to 6 months with 1-MCP treatments. The application of 1-MCP at 0.5 µL/L concentration is effectively and economically sufficient to maintain the quality of RubyS apples.

• ETRI Journal
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• v.42 no.1
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• pp.118-128
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• 2020

A semitransparent photovoltaic-thermal (PV/T) air collector can produce electricity and heat simultaneously. To maximize the thermal and overall efficiency of the semitransparent PV/T air collector, its availability should be maximum; this can be determined through a Markov analysis. In this paper, a Markov model is developed to select an optimized number of semitransparent PV modules in service with five states and two states by considering two parameters, namely failure rate (λ) and repair rate (μ). Three artificial neural network (ANN) models are developed to obtain the minimum cost, minimum temperature, and maximum thermal efficiency of the semitransparent PV/T air collector by setting its type appropriately and optimizing the number of photovoltaic modules and cost. An attempt is also made to achieve maximum thermal and overall efficiency for the semitransparent PV/T air collector by using ANN after obtaining its minimum temperature and available solar radiation.

• Journal of Advanced Marine Engineering and Technology
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• v.20 no.1
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• pp.56-66
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• 1996

In this study, the characteristics of generation and propagarion of transient wave induced in the assembly of four collecting plate upon the propagation of waves are analyzed. Also double exposure holographic inteferometry using ruby pulse laser is built in order to investigate the propagation of transient waves generated by impact load. When impact load was applied at edge of connecting band, the vibration of collecting plates was generated from the contact points between collecting plate and band which connects four collecting plates. Waves generated from the lower part and those reflected from the upper part were mixed as time went on and then formed very complex shapes. Also, when impact load was aplied at center of collecting plate, the waves propagating across the convexo-concave plane were reflected partly at curved section. Therefore the vibration amplitude was decreased as the transiet waves were propagated through the convexo-concave plane.

• Proceedings of the KIPE Conference
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• 2014.11a
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• pp.117-118
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• 2014

This paper presents a new smart power module for 100[kVA] inverter. In the inverter, the three smart modules are used and those are installed at the each pole of the inverter. Each module receives the switching functions from the inverter main controller, and generates duty ratio for IGBTs' switching of the pole. For the reliable operation of the inverter, CAN communication is used for transferring the switching functions form the main controller to the modules. Experiments verify the performance of the smart power module installed in 100[KVA] inverter.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.10
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• pp.3211-3223
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• 1996

In this paper, the propagation of elastic wave generated by loading impact to plates made of isotropic of anisotropic material was studied. And the influence of boundary conditions (free or clamped edge) upon the reflection of elastic wave was anlyzed. Also, double exposure holographic interferometer using ruby pulse laser was formed in order to investigate transient waves. Before the elasitc wave was reflected from the edges, the elastic wave of isotropic plate such as aluminum plate showed circular interferometric fringe pattern, whereas that of anisotropic plate such as epoxy composite laminates showed elliptical one. And the transverse displacement curves obtained from experiment and theory for both plates agreed well. Also, the waves reflected from the boundary edges showed much differences according to the boundary condition of edges.

• Advances in concrete construction
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• v.4 no.3
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• pp.161-172
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• 2016

An experimental investigation was carried out on the strength and behavior plain and fiber reinforced geopolymer concrete beam column joints and the results were compared with plain and steel fiber reinforced conventional concrete beam column joints. The volume fraction of fibers used was 0.5%. A total of six Geopolymer concrete joints and four conventional concrete joints were cast and tested under reversed cyclic loading to evaluate the performance of the joints. First crack load, ultimate load, energy absorption capacity, energy dissipation capacity stiffness degradation and moment-curvature relation were evaluated from the test results. The comparison of test results revealed that the strength and behavior of plain and fiber reinforced geopolymer concrete beam column joints are marginally better than corresponding conventional concrete beam column joints.

• Advances in concrete construction
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• v.9 no.2
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• pp.115-123
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• 2020

The performance of steel fiber reinforced geopolymer concrete beam column joints under cyclic loading was investigated. The volume fraction of fibers considered were 0.25% (19.62 kg/㎥), 0.5% (39.24 kg/㎥), 0.75% (58.86 kg/㎥) and 1% (78.48 kg/㎥). A total of fifteen specimens were prepared and tested under reverse cyclic loading. Test results were analyzed with respect to first crack load, ultimate load, energy absorption capacity, energy dissipation capacity, stiffness degradation and load deflection behavior. Test results revealed that the addition of steel fibers enhanced the performance of geopolymer concrete beam column joints significantly. The joints were analyzed using finite element software ANSYS. The analytical results were found to compare satisfactorily with the experimental values.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.130-130
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• 2000

타이타늄(CP Ti)과 타？늄합금은 인체의 골격을 구성하고 있는 물질과 가장 흡사한 물리적 성질과 우수한 생체적합성으로 인해 임플란트용 재료로 많이 사용되고 있으며, 최근에 인공관절이나 치근으로의 사용이 증가하고 있다. 그러나 교합면에서의 취약한 마모특성으로 인해 wear debris에 의한 골 흡수 및 이완 등을 야기하는 문제점으로, 이의 개선에 관한 연구가 활발히 진행되어 왔다. 다이아몬드상 카본 (Diamond-Like-Carbon) 박막은, 다이아몬드와 유사한 높은 경도, 내마모성 그리고 화학적 안정성 등의 매우 우수한 물리화학적 특성을 가지고 있는 박막재료로 고체 윤활박막으로서 hard disk나 VCR head drum의 보호막, 우주항공기의 bearing 재료코팅 등으로의 적용이 최근에 급격히 증가하고 있다. 본 연구에서는 이와 같은 특성을 지닌 다이아몬드상 카본 박막의 생체재료로의 적용을 위해, CP Ti과 Ti-6Al-4V에 13.56MHz를 사용하는 r.f PACVD법으로 DLC를 증착하여 생체적합적 특성을 조사하였다. C6H6 가스를 사용하여 1$\mu\textrm{m}$의 두께로 DLC 박막을 증착하였으며, 기판과의 밀찰력 향상을 위해 Si을 증간층으로 합성하였다. 마모특성은 pin-on-disk type wear tester을 사용하였으며 직경 5mm의 ruby ball로 실험을 수행하였다.