• Title/Summary/Keyword: Two-Layer Model

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Geochemical Experiment for Effective Treatment of Abandoned Mine Wastes (광산폐석의 효과적 처리를 위한 지화학적 연구)

  • 이진국;이재영
    • Journal of Korea Soil Environment Society
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    • v.3 no.1
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    • pp.31-44
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    • 1998
  • The geochemical experiments were carried out to investigate a removal effect of heavy metals in abdndoned metallic mine wastes, and to conceive a treatment techniques of them. In order to prevent contamination, experiment appature was made of acrylic acid resin and polyethylene which resist to acid and alkali. Experiment models are devided into four groups based on the system environments, distribution patterns and a kind of filling materials. The first group is background model(model I ) which is filled with waste only and opened to air. The second one is four layer group which is subdivided into two models, opened and closed systems, and the third mix group which is subdivided into three models based on mixing ratio of filling materials and system environment like a layered group. The forth is composed of two layer model, lower one composed of waste and upper one limestone chips. Solution drained from Model Ishows a high contents of heavy metals on the all terms of experiments. Among the models, however, the closed mix model V and Ⅶ show the most effective removal of heavy metals liberated from wastes. Models having different mixing ratios of filling materials on closed systems does not affect in heavy metal removal effect. But, the distribution patterns of filling materials affect very much on removal effect of heavy metals. The closed models with same constitution ratios and distribution patterns of filling materials show more and less effective removal to the open models.

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Magnetic Anisotropy in High $T_c\;Y_1Ba_2Cu_3O_{7-y}$ Superconductor (고온초전도체 $Y_1Ba_2Cu_3O_{7-y}$의 자기이방성)

  • Kim, Mun-Seok;Yu, Seong-Cho;Im, U-Yeong;Baek, Jong-Seong
    • Journal of the Korean Magnetics Society
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    • v.2 no.3
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    • pp.228-232
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    • 1992
  • Magnetic properties of grain aligned high $T_c\;Y_1Ba_2Cu_3O_{7-y}$ superconductor are inverstigated. Grain-aligned superconductors have magnetic anisotropy in the Cu-O layer like single crystals. The lower critical field $H_{c1},$ measured at the temperature range of 2 K up to 77 K, is found to be decreasing linearly as temperature goes up. Moreover, it decreaes more rapidly when the Cu-O layer is perpendicular to the external magnetic field. The temperature dependence of the magnetic susceptibility shows that the value of magnetic susceptibility, $4{\pi}\;X,$ is close to -1 at low temperature. The intra grain critical current density $J_c,$ obtained from the Bean's critical state model, is found to be comparable to that of single crystal superconductors.

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Radioprotective effects of dimethyl sulfoxide in the artificial skin reconstructed with cultured human cells (배양된 사람 세포를 이용해 제작한 인공피부에서 방사선조사에 대한 dimethyl sulfoxide의 보호 효과)

  • Ryu Young-Ha;Choi Karp-Shik;Song In-Hwan
    • Imaging Science in Dentistry
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    • v.32 no.1
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    • pp.11-18
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    • 2002
  • Purpose: To evaluate cultured human artificial skin as an experimental model for studying radiation effects in vitro. Materials and Methods: The skin was constructed by culturing keratinocytes over collagen lattice which made by culturing fibroblasts. Two groups were irradiated to gamma rays at single dose of 25 Gy with or without 3.5% of DMSO. Ultrastructures were investigated by electron microscopy after irradiation. The number of epidermal layers and expression of cytokeratin (CK) 14 & 10 were also seem by light microscopy. Results: At 2 days after irradiation in experimental group without DMSO, necrotic cells were rarely found in the spinosal layer and undercornified cells were visible in the homey layer. Similar findings were also found in experimental group with DMSO but in mild form. The number of epidermal layers in experimental group without DMSO were significantly fewer than other group. CK 14 expressed in all the layer excluding homey layer but CK 10 expressed over 3∼4 basal layers. Such patterns of CK expression were similar to all groups. It is suggested that structures of the keratinocytes and epidermal formation could be disturbed by irradiation in artificial skin and that DMSO can protect these damages. Conclusion : Therefore this work could be used as an organotypic experimental model in vitro using human cells for studying radiation effect in skin. Furthermore structural findings provided in this study could be used as useful basic data in further study using this model.

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An Artificial Recharge Test and Its Numerical Simulation for the Analysis of Seepage in the Songsanri Tomb Site of Kongju (공주 송산리고분군 누수현상 원인 분석을 위한 인공함양시험 및 수치모델링)

  • 구민호;서만철
    • The Journal of Engineering Geology
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    • v.9 no.1
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    • pp.1-15
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    • 1999
  • An artificial recharge test was performed to analyze the source of seepage observed inside the Songsanri tombs Kongju during the rainy season. In order to simulate simulate the test, a two-dimensional unsaturated groundwater flow model was developed. By the measured water level variation in the observation wells and in the artificail water tank, the model was cailbrated to estimate the model parameters such as fitting parameters in the constitutive relations(n and $\alpha$), the saturated volumetric water content, the residual volumetric water content, and the saturated hydraulic conductivity. Using the calibrated parameters, the recharge test was simulated. The results of the test and simulation show that the major source of the seepage is the downward groundwater flow through cracks in the protection layer the tombs. It was also analyzed by the steady state simulation that, with a perfect protection layer, a long-term precipitation that, with a perfect protection layer, a long-term precitation could cause only 10% increase of the effective saturation around the north side of the Muryong royal tomb by infiltration of the unsaturated groundwater from the North. Therefore, it is concluded that the most urgent protection plan for the tombs with respect to seepage is to reconstruct an effective waterproof-layer rather than a trenched drainage system.

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A Simple Model for Parasitic Resistances of LDD MOSFETS (LDD MOSFET의 기생저항에 대한 간단한 모형)

  • Lee, Jung-Il;Yoon, Kyung-Sik;Lee, Myoung-Bok;Kang, Kwang-Nham
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.27 no.11
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    • pp.49-54
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    • 1990
  • In this paper, a simple model is presented for the gate-voltage dependence of the parasitic resistance in MOSFETs with the lightly-doped drain (LDD) structure. At the LDD region located under the gate electrode, an accumulation layer is formed due to the gate voltage. The parasitic resistance of the source side LDD in the channel is treated as a parallel combination of the resistance of the accumulation layer and that of the bulk LDD, which is approximated as a spreading resistance from the end of the channel inversion layer to the ${n^+}$/LDD junction boundary. Also the effects of doping gradients at the junction are discussed. As result of the model, the LDD resistance decreases with increasing the gate voltage at the linear regime, and increase quasi-linearly with the gate voltage at the saturation regime, considering th velocity saturation both in the channel and in the LDD region. The results are in good agreement with experimental data reported by others.

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Web3 Business Model Innovation Approach and Cases of Korean Game Giants

  • Song, Minzheong
    • International Journal of Internet, Broadcasting and Communication
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    • v.16 no.1
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    • pp.241-252
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    • 2024
  • We analyze the types of Web3 business model innovation (BMI) of the six major Korean game companies by market size. As a result of the analysis, Nexon is watched as the adapter. It introduces blockchain (BC) layer 2, 'Polygon' to the extended ecosystem such as the creator's secondary creation, item utility, and compensation experience using the existing core intellectual property (IP). KakaoGames and Neowiz are watched as the adventurers. KakaoGames introduces BC layer 2, 'Polygon' and 'Near Protocol' to various experiments using tokenomics models in casual games and massively multiplayer online role-playing games (MMORPGs) using several existing popular IPs. Neowiz also introduces BC layer 2, 'Polygon' and 'Avalanche' to the IntellaX platform using existing game IPs. As the reinventor, Netmable positions as a game publisher that releases third-party games based on multi-chain infrastructure such as Klaytn, BNB Chain, Near Protocol, Aptos Foundation, and introduces BC to new core IPs. Finally, there are Wemade and Com2us as the mavericks. They aim to be the Web3 platform operators that create a BC layer 1 ecosystem and provide services that encompass BC games, GameFi, and non-fungible tokens (NFTs). Here are the implications of the four types of BMI. In terms of infrastructure, Nexon, KakaoGames, and Neowiz try to introduce a part of cross-chain, whereas Netmable tries to move toward a complete multi-chain strategy, and Wemade and Com2us also try to consider multi-chain, even if they have the full BC introduction. In terms of defending against market decline, Nexon and Netmable have a different position. Nexon which has a greater market dominance, only tries to continuously experiment, but Netmable is aggressively focusing on monetizing new products. Attacks on growth aspirations also show two different positions. KakaoGames and Neowiz only try to aggressively explore, while WeMade and Com2us try to set new standards for industrial innovation.

Shock Reflection and Penetration Impinging into a Vortex (I) - Experimental Model- (와동에 입사하는 충격파의 반사 및 투과(I))

  • Jang, Se-Myeong;Jang, Geun-Sik
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.26 no.9
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    • pp.1311-1318
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    • 2002
  • An experimental model is investigated in this paper using the experimental method with a shock tube and the numerical technique. The shock-vortex interaction generated by this model is visualized with various methods: holographic interferometry, shodowgraphy, and numerical computation. In terms of shock dynamics, there are two meaningful physics in the present problem. They are reflective wave from the slip layer at the vortex edge and transmitted shock penetrating the vortex core. The discussion in this study is mainly focused on the two kinds of waves contributing to the quadrupolar pressure distribution around the vortex center during the interaction.

A Development of One-dimensional Thermal Analysis Tool for Flight Vehicle with Cork Insulation (코르크 삭마를 고려한 비행체 1D 온도해석 도구 개발)

  • Jeong, Taebin
    • Journal of the Korea Institute of Military Science and Technology
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    • v.21 no.4
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    • pp.464-470
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    • 2018
  • A development of one-dimensional thermal analysis tool is performed to estimate the thickness of cork insulation for flight vehicle. In the calculation of cork temperature, the cork density model, heat of ablation and pyrolysis gas enthalpy model were applied. The calculation for the two-layer model of cork and metal was performed by the tool and compared with the experimental data. The results for the two aerodynamic heating conditions were 17 % and -12 % different from the experimental data, respectively. The effect of mechanical ablation not included in the calculation can be expected as the cause of the difference. The temperature-density curve of cork which adjusted by experimental data was also presented.

Reflected Wave and Transmitted Shock in the Shock-Vortex Interaction (충격파-와동 간섭에서 발생하는 반사파 및 관통 충격파)

  • Chang Se-Myong;Chang Keun-Shik;Lee Soogab
    • Proceedings of the KSME Conference
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    • 2002.08a
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    • pp.139-142
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    • 2002
  • An experimental model and a conceptual model are investigated in this paper with both shock tube experiment and numerical technique. The shock-vortex interaction generated by this model is visualized with various methods: holographic interferometry, shodowgraphy, and numerical computation. In terms of shock dynamics, there are two meaningful physics in the present problem. They are reflective wave from the slip layer at the vortex edge and transmitted shock penetrating the vortex core. The discussion in this study is mainly focused on the two kinds of waves contributing to the quadrupolar pressure distribution around the vortex center during the interaction.

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Polysilicon anti-sticking structure by grain etching technique (결정립 식각 기술을 이용한 다결정 실리콘 부착 방지 구조)

  • 이영주;박명규;전국진
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.35D no.2
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    • pp.60-69
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    • 1998
  • Polysilicon surface mdoification tecnique is developed to reduce the sticking of microstructures fabricated by micromachining. Modified anti-sticking grain holes are simply formed by two-step dry eth without additional photolithography nor deposition of thin films. Both process-induced sticking and in-use sticking are successfully reduced more than two times by adopting grain holed polysilicon substrate. A sticking model for cantilever beam is derived. This model includes bending moment stems from stress gradient along the thickness directionof structural polysilicon. Because the surface tension of rinse liquid and the surface energy of the solids to be stuk tend to decrease in recently developed anti-sticking techniques, the effect of stress gradient will play an important role to analyze the sticking phenomena. Effect of the temperature during post-release rinse and dry is modelled and verified experimentally. Based on developed anti-sticking polysilicon structure and the sticking model, sticking of microstructure, fabricated by simple wet process including sacrificial layer etch and rinse with deionized water without special equimpment for post-release rinse and dry was alleviated more than 3.5 times.

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