• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.200-200
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• 2011

Hierarchical mesoporous ZSM-5 with enhanced mesoporosity was synthesized by microwave through the rapid assembly via ionic interaction between sulfonic acid functionalized ZSM-5 nano particles and cationic surfactant. The catalytic performance of enhanced accessibility due to mesoporosity and acidity were investigated in the alkylation of mesitylene with benzyl alcohol as alkylating agent. The effect of mole ratio of aromatic with benzyl alcohol, reaction time and alkylation agent were also studied. The enhanced mesoporosity and acidity of sulfonic acid functionalized mesoporous ZSM-5 induced activity enhancement compared with non-functionalized mesoporous ZSM-5, sulfonic functionalized mesoporous ZSM-5 synthesized by hydrothermal method and conventional microporous ZSM-5. The sulfonic acid functionalized mesoporous ZSM-5 showed much higher chemoselectivity of benzylated mesitylene than others, whereas the others mainly show dibenzyl ether as product. This significant difference in catalytic selectivity was resulted from the existence of mesopores, which definitely allowed the benzylation in mesopores.

• Journal of Contemporary Eastern Asia
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• v.13 no.1
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• pp.57-68
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• 2014

This paper positions the triple-Helix as a meso-level notion, an epicycle in a grander circle of technological change, institutional change, and psychological change. Because of the differing speeds of these several kinds of change, speed is proposed as a high-level system metric. This implies that what we commonly call bridging agencies or facilitators - lawyers, venture capitalists, incubators, etc. - are better called buffering agencies, as they help to engage entities changing at different speeds. They use human judgment as well as information technologies to choose feasible timing for these engagements. The paper highlights implications for thinking about innovation diffusion: The grand cycle of socio-technical change means we should, rather, think in terms of innovation reinforcement, or a circle of innovation.

• Journal of Ocean Engineering and Technology
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• v.20 no.5 s.72
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• pp.23-29
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• 2006

A quasi depth-varying mathematical model for wind-generated circulation in coastal areas, expressed in terms of the depth-averaged horizontal velocity components and free surface elevation was validated and used to understand the diurnal circulation process. The wind velocity is considered as a dominant factor for driving the current. In this paper, three-dimensional numerical experiments that included the land topography were used to investigate the mesoscale air flaw over the coastal regions. The surface temperature of the inland area was determined through a surface heat budget consideration with the inclusion of a layer of vegetation.A series of numerical experiments were then carried out to investigate the diurnal response of the air flaw and wind-generated circulation to various types of surface inhomogeneities.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.04a
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• pp.419-421
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• 2017

최근 서버 가상머신의 단점을 보완하고 클라우드 컴퓨팅 서비스의 민첩성을 향상시키기 위해서 공유 환경 각각의 운영체제 위에 애플리케이션이 동작하는 대신 공통으로 사용하는 운영체제를 공유하는 컨테이너 기술이 부각되고 있다. 그러나 여러 컨테이너 노드를 사용자가 동시에 제어, 운용하는데 있어서는 시스템 운용 복잡도가 높고 어렵다. 이를 해결하기 위해 Kubernetes, Swarm, Mesos와 같은 다수의 컨테이너 노드를 통합 배포 및 제어 할 수 있는 컨테이너 오케스트레이션 기술이 등장하였다. 본 연구에서는 더 나아가 컨테이너 서비스의 워크로드 형태에 따라 적합한 컨테이너 오케스트레이터를 선택하고 컨테이너 클러스터 서비스를 통합 운영 할 수 있는 기술을 개발하였다.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.5
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• pp.97-103
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• 2006

A meso-scale analysis method using the natural element method, which is a kind of meshless method, is proposed for the analysis of material damage of brittle microcracking solids such as ceramic materials, concrete and rocks. The microcracking is assumed to occur along Voronoi edges in the Voronoi diagram generated using the nodal points as the generators. The mechanical effect of microcracks is considered by controlling the material constants in the neighborhood of the microcracks. The macro elastic moduli of anisotropic as well as isotropic solids containing a number of randomly distributed microcracks are calculated in order to demonstrate the validity of the proposed method.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.6
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• pp.716-723
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• 2006

A meso-scale analysis method using the natural element method is proposed for the analysis of material damage of brittle microcracking solids. The microcracking is assumed to occur along Voronoi edges in the Voronoi diagram generated using the nodal points as the generators. The mechanical effect of microcracks is considered by controlling the material constants in the neighborhood of the micorcracks. The macro elastic moduli of isotropic solids containing a number of randomly distributed microcracks are calculated considering the effect of microcrack closure to demonstrate the validity of the proposed method.

• Journal of Sensor Science and Technology
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• v.19 no.2
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• pp.112-117
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• 2010

A high-throughput sorting (HTS) system has been designed to separate target particles using a negative dielectrophoretic (n-DEP) force. The system consists of a meso-sized channel and a cantilever-type electrode(CE) array designed to separate a large number of target particles by discerning subtle difference of weight and dielectric material property of the particles. Using the polystyrene beads with various sizes of 10, 25 and $50{\mu}m$, the developed system exhibits high-throughput sorting of about 200 beads/sec and more than 80 % of separation efficiency.

• Transactions of Materials Processing
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• v.15 no.3 s.84
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• pp.247-254
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• 2006

Rather than traditional manufacturing processes, miniature manufacturing processes usually require sophisticated equipments and characteristics of the processes of high cost and of low productivity. Contrarily, miniature stamping process can be realized in a low cost high productivity with relatively inexpensive equipments. In the meso scale, mechanical properties, especially work hardening characteristics, are discovered to be statically scattered and size dependent by intensive experimental and numerical investigations, which make the stamping process hard to apply to the miniature manufacturing. In this study, dual purpose experimental device that can be used for both miniature scale tensile test and miniature scale stamping by simple change of attachment has been developed. For the tensile test, the elongation has been measured with a combined use of a CCD camera and a linear encoder in order to account for the possibility of slippage between specimen and the grip and to ensure the accuracy of the measurement, while load has been measured with a load cell. To satisfy the required material properties for stamping, optimal annealing condition has been found by examining the microstructure of annealed specimen.

• International Journal of Precision Engineering and Manufacturing
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• v.6 no.2
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• pp.5-11
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• 2005

Among the micro machining techniques, micro EDM is generally used for machining micro holes, pockets, and micro structures on difficult-cut-materials. Micro EDM parameters such as applied voltage, capacitance, peak current, pulse width, duration time are very important to fabricate the tool electrode and produce the micro structures. Developed micro EDM machine is composed of a 3-axis driving system and RC circuit equipped with pulse generator. In this paper, using micro EDM machine, the characteristics of micro EDM process are investigated and it is applied to micro holes, slots, and pockets machining. Through experiments, relations between machined surface and voltages and between MRR and feedrate are investigated. Also the trends of tool wear are investigated in case of hole and slot machining.

• Journal of Electrochemical Science and Technology
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• v.5 no.3
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• pp.65-72
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• 2014

The use of nanoscale electrocatalysts is a promising strategy for achieving high catalyst activity due to their large surface area. However, catalyst activity is not directly correlated to particle size. To understand this discrepancy, many studies have been conducted, but a full understanding has still not been achieved, despite the importance of particle size effects in designing an active catalyst. In this review, we focus on the discussion of particle size effects on the oxygen reduction reaction, and also discussed the nanoscale design beyond the nanoparticle to the meso and macroscale design.