• Title/Summary/Keyword: hybrid science

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Chromate-free Hybrid Coating for Corrosion Protection of Electrogalvanized Steel Sheets

  • Jo, Du-Hwan;Kwon, Moonjae;Kim, Jong-Sang
    • Corrosion Science and Technology
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    • v.11 no.1
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    • pp.15-19
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    • 2012
  • Both electrogalvanized and hot-dip galvanized steel sheets have been finally produced via organic-inorganic surface coating process on the zinc surface to enhance corrosion resistance and afford additional functional properties. Recently, POSCO has been developed a variety of chromate-free coated steels that are widely used in household, construction and automotive applications. New organic-inorganic hybrid coating solutions as chromate alternatives are comprised of surface modified silicate with silane coupling agent and inorganic corrosion inhibitors as an aqueous formulation. In this paper we have prepared new type of hybrid coatings and evaluated quality performances such as corrosion resistance, spot weldability, thermal tolerance, and paint adhesion property etc. The electrogalvanized steels with these coating solutions exhibit good anti-corrosion property compared to those of chromate coated steels. Detailed components composition of coating solutions and experimental results suggest that strong binding between organic-inorganic hybrid coating layer and zinc surface plays a key role in the advanced quality performances.

Analysis of Textile Supply Chain Network with ODM-OEM Hybrid Production System in FTA Environment (FTA 환경에서 ODM-OEM Hybrid 형태의 섬유류생산시스템의 공급망 분석)

  • Byun, Taesang;Oh, Jisoo;Jeong, Bongju
    • Korean Management Science Review
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    • v.30 no.1
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    • pp.25-41
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    • 2013
  • This paper presents a supply chain framework with the ODM (Original Design Manufacturing)-OEM (Original Equipment Manufacturing) hybrid production of textile industry in FTA (Free Trade Agreements) environments between Korea and other countries. The proposed supply chain framework with ODM-OEM hybrid production is a unique supply chain that has both domestic production with non-tariff advantages in FTA environment and oversea production with low labor costs. To investigate the validity of the proposed supply chain, we first construct its strategic profit model and supply chain planning and then show that each member of supply chain network-yarn manufacturer, fabric manufacturer, and apparel manufacturer-can maximize their own profits without conflicts among the members. The efficiency of the ODM-OEM hybrid production system is analytically verified in comparison with the general OEM and ODM production model using profit models. Comprehensive numerical examples are provided to illustrate the advantages of the proposed system.

A Design of Hybrid Production System using GT, MRP & JIT (GT, MRP, JIT의 혼합 생산 시스템 구축)

  • 이현용;송준엽;강경식
    • Journal of the Korea Safety Management & Science
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    • v.3 no.1
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    • pp.93-105
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    • 2001
  • Many production management systems for increasing productivity, minimizing inventory, keeping due dates and maximizing use of resources have been proposed, and GT, MRP and JIT are frequently used among these systems. The three systems have merits and demerits through comparing with each other. Because each system has mutual dependence, a hybrid production system Is necessary for using their merits maximally. In this study, a hybrid production system is designed by combining GT, MRP and JIT, which is suitable in the domestic production system and it is presented as followings. -. Basic research works for G7, MRP and JIT. -. Comparison and analysis are carried out for each system.- . The hybrid production system is designed. -. The hybrid production system is developed.

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Dynamic Simulation of a Hybrid Cooling System utilizing Heat Pump, Desiccant and Evaporative Cooler (열펌프, 데시칸트 및 증발식 냉각기를 조합한 하이브리드 냉방 시스템의 동특성 해석 연구)

  • Seo, Jung-Nam;Kim, Young-Il;Chung, Kwang-Seop
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.7 no.1
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    • pp.45-50
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    • 2011
  • Hybrid desiccant cooling system(HDCS) consists of desiccant rotor, regenerative evaporative cooler, heat pump and district heating hot water coil. In this study, TRNSYS and EES, dynamic and steady simulation programs were used for studying hybrid desiccant cooling system which is applied to an apartment house from June to August. The results show that power consumption of the hybrid desiccant cooling system is 70 kWh in June, 199 kWh in July and 241 kWh in August. Sensible and latent heats removed by the hybrid desiccant cooling system are 300 kWh, 301 kWh in June, 610 kWh, 858 kWh in July and 719 kWh, 1010 kWh in August. COP of the hybrid desiccant cooling system is 8.6 in June, 7.4 in July and 7.2 in August. COP of the hybrid desiccant cooling system decreases when latent heat load increases. Operation time of the system is 70 hours in June, 190 hours in July and 229 hours in August. Since the cooling load is largest in August, the operation time of August is longest for maintaining the indoor temperature at $26^{\circ}C$. Due to the characteristics of hybrid desiccant cooling system for efficiently handling both sensible and latent loads, this system can handle sensible and latent heat loads efficiently in summer.

Electrical and Optical Properties of Transparent Conducting Films having GZO/Metal/GZO Hybrid-structure; Effects of Metal Layer(Ag, Cu, Al, Zn) (GZO/Metal/GZO 하이브리드 구조 투명 전도막의 전기적, 광학적 특성; Ag, Cu, Al, Zn 금속 삽입층의 효과)

  • Kim, Hyeon-Beom;Kim, Dong-Ho;Lee, Gun-Hwan;Kim, Kang-Ho
    • Journal of the Korean institute of surface engineering
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    • v.43 no.3
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    • pp.148-153
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    • 2010
  • Transparent conducting films having a hybrid structure of GZO/Metal/GZO were prepared on glass substrates by sequential deposition using DC magnetron sputtering. Silver, copper, aluminum and zinc thin films were used as the intermediate metal layers in the hybrid structure. The electrical and optical properties of hybrid transparent conducting films were investigated with varying the thickness of metal layer or GZO layers. With increasing the metal thickness, hybrid films showed a noticeable improvement of the electrical conductivity, which is mainly dependent on the electrical property of the metal layer. GZO(40 nm)/Ag(10 nm)/GZO(40 nm) film exhibits a resistivity of $5.2{\times}10^{-5}{\Omega}{\cdot}cm$ with an optical transmittance of 82.8%. For the films with Zn interlayer, only marginal reduction in the resistivity was observed. Furthermore, unlike other metals, hybrid films with Zn interlayer showed a decrease in the resistivity with increasing the GZO thickness. The optimal thickness of GZO layer for anti-reflection effect at a given thickness of metal (10 nm) was found to be critically dependent on the refractive index of the metal. In addition, x-ray diffraction analysis showed that the insertion of Ag layer resulted in the improvement of crystallinity of GZO films, which is beneficial for the electrical and optical properties of hybrid-type transparent conducting films.

Feasibility of Improving the Accuracy of Dose Calculation Using Hybrid Computed Tomography Images: A Phantom Study

  • Jeon, Hosang;Kim, Dong Woon;Joo, Ji Hyeon;Ki, Yongkan;Kim, Wontaek;Park, Dahl;Nam, Jiho;Kim, Dong Hyeon
    • Progress in Medical Physics
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    • v.32 no.1
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    • pp.18-24
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    • 2021
  • Purpose: Kilovoltage computed tomography (kV-CT) is essential for radiation treatment planning. However, kV-CT images are significantly distorted by artifacts when a metallic prosthesis is present in the patient's body. Thus, the accuracies of target delineation and treatment dose calculation are inevitably lowered. We evaluated the accuracy of the calculated doses using an image restoration method with hybrid CT, which was introduced in our previous study. Methods: A cylindrical phantom containing four metals, namely, silver, copper, tin, and tungsten, was scanned using kV-CT and megavoltage CT to produce hybrid CT images. We created six verification plans for three head and neck patients on kV-CT and hybrid CT images of the phantom and calculated their doses. The actual doses were measured with film patches during beam delivery using tomotherapy. We used the gamma evaluation method to compare dose distribution between kV-CT and hybrid CT with three gamma criteria, namely, 3%/3 mm, 2%/2 mm, and 1%/1 mm. Results: The gamma pass rates decreased as the gamma criteria were strengthened, and the pass rate of hybrid CT was higher than that of kV-CT in all cases. When the 1%/1 mm criterion was used, the difference in gamma pass rates between them was up to 13%p. Conclusions: According to our findings, we expect that the use of hybrid CT can be a suitable approach to avoid the effect of severe metal artifacts on the accuracy of dose calculation and contouring.

Morphological, Cytological and Molecular Evidence for Intersubgeneric F1 Hybrid between Glycine max x G. tomentella (콩 Glycine max와 G. tomentella의 종간교잡으로부터 얻은 Fl식물체 검증을 위한 형태적 · 세포학적 · 분자유전학적 연구)

  • Choi, In-Soo;Kim, Yong-Chul
    • Journal of Life Science
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    • v.18 no.4
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    • pp.454-460
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    • 2008
  • This study was carried out to demonstrate morphological, cytological and molecular evidence for intersubgeneric $F_1$ hybrid between Glycine tomentella and G. max cv. ‘Baemkong’. Morphological features of $F_1$ plant for pistil and stamen, flower color and growth habit showed intermediate type between G. tomentella and G. max cv. ‘Baemkong’. Chromosome number of $F_1$ plant was 2n=39, which explained the evidence of $F_1$ hybrid between G. tomentella (2n=38) and G. max cv. ‘Baemkong’ (2n=40). Polyacrylamide isoelectric focusing pattern for esterase and peroxidase also showed that the $F_1$ plant was true $F_1$ hybrid between G. tomentella and G. max cv. ‘Baemkong’. From RAPD analysis, we identified that 62 primers showing bands in $F_1$ hybrid had both bands from G. tomentella and G. max cv. ‘Baemkong’, which suggested that this was true $F_1$ hybrid. Based on our results from morphological, cytological and molecular analyses, we suggest that the $F_1$ plant was true intersubgeneric hybrid between G. tomentella and G. max cv. ‘Baemkong’. Our results still remain us further study to recover fertility of $F_1$ hybrids. The occurrence of maternal and/or paternal inheritance in $F_1$ hybrid from intersubgeneric cross between G. tomentella and G. max cv. ‘Baemkong’ need to be explained.

Performance Analysis of Type-I Hybrid ARQ System Considering Transmission Delay Time (전송 지연시간을 고려한 Type-I Hybrid ARQ 시스템의 성능 분석)

  • 조치원;유흥균
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.10 no.6
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    • pp.879-888
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    • 1999
  • A Study on the ARQ scheme of data error control is important for more reliable information transmission. Since performance difference is large by the long transmission delay time in satellite communication, the performances of SR ARQ and conventional type-I hybrid ARQ with fixed code rate are investigated by using the parameters of packet length, channel capacity, BER, and transmission delay time especially. BCH code is used in type-I hybrid ARQ for FEC method. This paper presents the throughput analyses according to such various parameters as BCH code rate, window size, data rate and round-trip delay time. Especially we derive a performance equation of type-I hybrid ARQ with the factor of the transmission delay time using the equation of SAW ARQ. Also, the performance of type-I hybrid ARQ specially considering transmission delay time is analyzed through numerical analysis and computer simulation so we can get a important characteristics variation.

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Comparison of learning effects between hybrid flipped learning and flipped learning (하이브리드 플립드 러닝과 플립드 러닝의 학습 효과 비교)

  • Bo-ram Choi
    • Journal of Korean Physical Therapy Science
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    • v.31 no.2
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    • pp.90-104
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    • 2024
  • Background: Hybrid learning is an educational approach that combines the teaching methods of online and lecture-style classes to compensate for each method's strengths and weaknesses. Compared to lecture-style classes, flipped learning improves overall class satisfaction and self-directed learning but is associated with lower learning motivation. It is necessary to determine whether hybrid flipped learning can solve the learning motivation problem of flipped learning by incorporating flipped learning into hybrid learning. The purpose of this study is to compare the effects of hybrid flipped learning and flipped learning on students' learning ability. Design: Cross-sectional study Methods: For students in the Department of Physical Therapy, classes were conducted using both flipped learning and hybrid flipped learning. In both learning methods, students took online classes first and participated in them every week. Flipped learning classes was conducted offline at school every week, while hybrid flipped learning alternated between live classes on YouTube and offline classes at school every other week. Results: Hybrid flipped learning resulted in significantly lower learning satisfaction and course evaluation than flipped learning, with no significant difference in grades. Conclusion: Hybrid flipped learning was able to cope with the situation well with the non-face-to-face teaching method caused by COVID-19, but it was difficult to improve learning ability because there were restrictions on activities that could interact with students. Flipped learning is a smooth offline activity that enables two-way activities between professors and students to improve learning ability, but the effect of improving test scores is still unclear.

Current Status of Comparative Mapping in Livestock

  • Lee, J.H.;Moran, C.;Park, C.S.
    • Asian-Australasian Journal of Animal Sciences
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    • v.16 no.10
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    • pp.1411-1420
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    • 2003
  • Comparative maps, representing chromosomal locations of homologous genes in different species, are useful sources of information for identifying candidate disease genes and genes determining complex traits. They facilitate gene mapping and linkage prediction in other species, and provide information on genome organization and evolution. Here, the current gene mapping and comparative mapping status of the major livestock species are presented. Two techniques were widely used in comparative mapping: FISH (Fluorescence In Situ Hybridization) and PCR-based mapping using somatic cell hybrid (SCH) or radiation hybrid (RH) panels. New techniques, using, for example, ESTs (Expressed Sequence Tags) or CASTS (Comparatively Anchored Sequence Tagged Sites), also have been developed as useful tools for analyzing comparative genome organization in livestock species, further enabling accurate transfer of valuable information from one species to another.