• Journal of Industrial and Engineering Chemistry
• /
• v.67
• /
• pp.140-147
• /
• 2018

The performance of a hydrate anti-agglomerant (AA) on cyclopentane (CyC5) hydrate anti-agglomeration at various concentrations (0-1 wt%, based on the oil phase) using MMF apparatus has been investigated. At low AA concentrations up to 0.01 wt%, the AA reduces the cohesion force (capillary force) by reducing the CyC5-water interfacial tension. At concentrations higher than 0.1 wt%, hydrate hydrophobicity alternation and AA's thermodynamic inhibition effects are the main part of AA's mechanism. Additionally, a "temporary agglomeration" phenomenon caused by surface melting of the hydrate particles is also observed, which may indicate the AA's weak ability to produce stable water-CyC5 interface.

• Journal of the Korean Geographical Society
• /
• v.52 no.1
• /
• pp.55-71
• /
• 2017

This paper points out the semantic unclearness of the jargon "cluster" and suggests the substitution of "industrial cluster" for "cluster". Industrial cluster is the intersection of industrial agglomeration and cluster phenomenon while the actual concept of cluster includes not only industry cluster but also political administration cluster, science research cluster, art cluster, religion cluster, education cluster, etc. Partially reconstructing the concept and significance of industry cluster, industrial cluster is a geographic agglomeration of interconnected productional businesses in a particular industry, forming close industrial networks. The advantage of the agglomeration includes reducing the transaction cost between the businesses, promoting technological innovation and dispersion, facilitating the utilization of the professional workforce, sharing and connecting the external customer. Moreover, this paper discusses the range of the industrial cluster and its distinctness from the other similar concepts. There is a need to discriminate it from the other related jargons and to clarify their relationship. In particular, there is a task to eradicate the mixed usage of industrial cluster with the jargons related to space for learning and innovation.

• Journal of the Korean Ceramic Society
• /
• v.56 no.2
• /
• pp.153-159
• /
• 2019

In this study, fly ash of a fluidized bed boiler produced in a power plant was stabilized by hydration and carbonation reaction. Then, each raw material was pulverized by two kinds of grinding equipment (Planetary mills and pot mills); the degree of grinding and the agglomeration behavior were observed. It was found that there were changes of specific surface area and particle size distribution according to grinding time. The surface of the raw material was observed using an optical microscope. As a result, agglomerates of about 75 ㎛ or more due to electrostatic phenomenon were formed as the grinding time became longer; it was confirmed that the crushing efficiency slightly increased with use of antistatic agent.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1999.05a
• /
• pp.442-446
• /
• 1999

Melting behavior and bridge phenomenon of solder paste, which is essential for surface mount technology in packaging, were investigated. solder paste of Sn-37%Pb was printed on Sn-coated Cu-pattern of PCB, and heated over melting point. Melting behavior of the paste was observed using CCD-camera. In order to modelize the melting and agglomeration phenomena of the paste, two solder balls of 0.76mm diameter were used. As experimental results, the paste start to melt from the margin of the printed shape. The hight of the melted paste decreased from 270 $\mu$m to 200 $\mu$m firstly, and finally recovered to 250 $\mu$m. During the melting procedure, pores were evolved from the molten paste. Bridge Phenomenon of the molten Paste depends upon the pitch of the pattern.

• Journal of Surface Science and Engineering
• /
• v.57 no.5
• /
• pp.406-415
• /
• 2024

Using DC magnetron sputtering, we deposited a bilayer composed of a seed layer consisting of Ti, Cr, Co, and Zr, and an overlayer of Ag on MgO(001) single crystal substrates, creating self-assembled nanostructures. When Ti was used as the seed layer, it was observed that the formed nano-dots inherently aggregated into dot shapes. Additionally, Cr, Co, and Zr were chosen to investigate their influence on SLAA(Seed layer Assisted Agglomeration) depending on the seed layer material, revealing different shapes of the formed nano-dots. Moreover, it was observed that aggregation was inhibited as the thickness of the seed layer exceeded a critical point. X-ray diffraction analysis of the Ti seed layer revealed epitaxial growth of Ag along the (001) direction of the MgO substrate. In contrast, no epitaxial growth was observed when Cr, Co, and Zr were used as seed layer materials. Ultimately, Ti was identified as the most suitable seed layer material for the fabrication of self-assembled nanostructures utilizing the aggregation phenomenon of the bilayer. This research is deemed sufficiently valuable in addressing the limitations associated with the low productivity and high cost of current nano thin film processes.

• Advances in nano research
• /
• v.2 no.2
• /
• pp.89-98
• /
• 2014

A novel and simple method for the synthesis of nano-magnetite particles is disclosed. In the novel procedure, $Fe^{2+}$ is the only source of metal cation. Carboxymethylcellulose (CMC) is used as the structure directing agent. The phase analysis of the nano-particles was performed using XRD and electron diffraction techniques. Size and morphology analysis was performed using light scattering and TEM techniques. The effect of $NH_4OH$ solution (32 wt. %) at different CMC concentrations on the size distribution of the final magnetite powders is studied. An optimal base concentration exists for each CMC concentration leading to minimal agglomeration. There exists a minimum CMC concentration (0.0016 wt. %), lower than that no magnetite forms. It is shown that using the new method, it is possible to immobilize a lipase enzyme (Candida Rugosa) with immobilization efficiency larger than 98 % with a loading more than 3 times the reported value in the literature. The latter phenomenon is explained based on the agglomerate state of the nano-particles in the liquid phase.

• Proceedings of the IEEK Conference
• /
• 2003.07b
• /
• pp.675-678
• /
• 2003

본 논문에서는 N-type 기판에서 Nickel-Silicide를 적용하였을 경우에 나타나는 문제점과 PAI (Pre-amorphization Implant)의 효과에 대하여 알아보았다. N-type 기판에 RTP (Rapid Thermal Process)를 통하여 Nickel-Silicide 를 형성하게 되는데, 여기까지는 안정한 Nickel mono-Silicide (NiSi)가 형성됨을 확인하였다. 하지만 후속 열처리 공정 후 심한 응집 현상 (Agglomeration)과 이상 산화 현상 (Abnormal Oxidation Phenomenon), Silicide Island 등 열안정성 (Thermal Stability) 측면에서 여러 가지 많은 문제점들이 나타났다. 이 후속 열처리의 열안정성 취약점들을 극복하는 방안으로 Ge 및 N₂ PAI를 적용하였다. PAI를 적용하였을 경우에는 그렇지 않은 경우에 비하여 고온 열처리 후에도 면저항이 비교적 잘 유지되었으며, 두께가 얇고 안정한 Nickel-Silicide 특성을 확보할 수 있었다. 특히 Ge PAI 에 비하여 N₂ PAI 의 경우가 보다 특성 개선 효과가 크게 나타났다.

• Journal of Environmental Health Sciences
• /
• v.22 no.4
• /
• pp.1-9
• /
• 1996

Experiments have been made to test the practical feasibility of using calcined manganese ore to desulfurize hot reducing gas. In this study, the effects of particle size of sorbents, temperature of sulfidation, flow rate and sorbent characteristics on the $H_2S$ removal efficiency of calcined manganese ore were investigated. Experimental results showed that the removal efficiency of $H_2S$ was optimum when the temperature was about 800$\circ$C and that the smaller particle size the higher the $H_2S$ removal efficiency. When the temperature was above 800$\circ$C, the reactivity of sorbent has lowered because agglomeration of sorbent increased intraparticle transport resistance, and this phenomenon was confirmed by SEM photographs. As the temperature increases, capacity for the $H_2S$ removal was increased but the equilibrium concentration of $H_2S$ was not affective.

• Journal of Industrial Convergence
• /
• v.14 no.1
• /
• pp.39-45
• /
• 2016

This paper deals with the consideration of mathematical models with regards to growth of cluster and firms by reviewing the Metcalf and Breuner's articles. prior studies have been argued the phenomenon of local industrial clusters and districts. Several concepts have been adopted to support the success of and changes to these clusters and firm growth. Through the review of two papers, evolution of both cluster and firm growth may be achieved in terms of utilizations of the different local aspects and mechanisms. This paper supports the theoretical back bone with regards to the regional cluster policy implementing in Korea for the purpose of regional developments. In particular, a mathematical model that, on a more abstract level, captures the fundamental dynamic structure of all the observed mechanisms. On the basis of this model, the emergence and evolution of local clusters can be described. Also this model has given that the knowledge sharing between firms has an important role to firms and cluster' growth.

• Korean Journal of Food Science and Technology
• /
• v.30 no.2
• /
• pp.385-390
• /
• 1998

The effect of agglomeration treatment was examined to prevent the parched cereal powder from clumping when it is blended with water. Parched cereal powder was composed of 66.9% carbohydrate, 7% water, 12.1% crude protein, 12.1% crude fat and 1.9% ash, respectively. Particle size of parched cereal powder was generally enlarged by agglomeration treatment. This phenomenon was confirmed by particle size analyzer and microscopic observation. The color of agglomerated sample was shown to be slightly darker than the untreated sample. The water absorption indices of agglomerated samples which were steamed for 2min and re-dried were significantly increased as compared with the untreated sample. The water solubility indices of agglomerated samples showed generally lower values than those of untreated samples. In views of quality and processing time, the optimum condition of agglomeration treatment for manufacturing well-dispersable parched cereal powder in water was 15min re-drying after 2min steaming. It is concluded that the agglomeration treatment improves the dispersibility of parched cereal powder and thus facilitates the intake of it after mixing with water.