• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.1
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• pp.63-67
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• 2009

The effects of adhesive substrates and bottom materials on the release of fertilized eggs by the Pacific cod, (Gadus macrocephalus) were examined to find an effective release method. Palm twin as an adhesive substrate displayed a significantly elevated adhesive rate compared to gulf weed. However, the survival rate of the fertilized eggs attached to palm twin was as low as 17.5% 8 days after fertilization (DAF). In contrast, fertilized eggs in the absence of adhesive substrate displayed the highest survival rate (47.0%). Concerning bottom materials, the survival rate of fertilized eggs on sand was significantly high (approximately 51.1%) on 8 and 9 DAF. The observations indicates that adhesive substrates are not needed and spawning ground bottom materials such as sand or mud should be considered when releasing fertilized eggs of Pacific cod.

• Ocean and Polar Research
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• v.45 no.1
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• pp.1-9
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• 2023

Marine microalgae have different collection methods depending on their habitat. In the case of adhesive microalgae, it is difficult to separate organisms from the substrate surface, and contamination is likely to occur during the sampling process. In this study, we analyzed the collection efficiency of adhesive microalgae using three artificial fiber materials (nylon, blend fabric, and viscose rayon). Each fiber showed different fiber diameter and pore characteristics (nylon 26.09 ㎛, blend fabric 56.6 ㎛, viscose rayon 101.3 ㎛). In addition, attached organisms were collected on the surface of artificial substrates at Bukseong Port in Incheon using each tested fiber material. After that, we investigated the population and species composition. The highest number of cells was found in nylon, which was 8 times higher than in the least collected viscose rayon material. In addition, we identified 24 microalgal species from the substrate, demonstrating that the species composition differed from that of surface water. The number of collected microalgae species varied depending on the fiber materials, with nylon containing all the adhesive microalgae. In contrast, only a few microalgae were observed in other fibers. These results suggest that, of the tested fibers, nylon material may be suitable for collecting adhesive microalgae. As a result, this study may be useful for future research on adhesive microalgae.

• Polymer(Korea)
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• v.39 no.3
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• pp.514-521
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• 2015

In this study, we would like to describe peel strength and dynamic shear property on various substrates of multi-layered structural double-sided adhesive tape with or without adhesive (AD) prepared by UV curing for an automobile, construction, and display junction. According to adapt the adhesive, the peel and dynamic shear strength of adhesion tape prepared with acrylic foam or various plastic substrates increased with increasing molecular weight, however, decreased over 650000 molecular weight. The adhesion property shows high value at the thin AD layer with decreasing temperature. The interface property shows highest at MW 615000 (AD-4), and the interface junction below MW 615000 resulted to divide from acrylic foam and adhesive layer. From this study, the multi-layered structural double-sided adhesive tapes seem to be a useful for industrial area such as a low surface energy plastic material and curved substrate.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.113-116
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• 2006

Some nano hair systems in the nature are found to show excellent adhesive characteristic, which is called dry adhesive, and synthetic nano hairs to mimic these adhesiveness are believed to have many applications. To develop a practical synthetic dry adhesive system, we mold nano hairs on plastic substrates using thermoplstic materials including COC, PP, PC and PMMA. and estimate the moldability and the adhesive characteristic. As a template for molding nano hairs, AAO membrane is first adopted, which is 60um thick and 13mm in diameter. This membrane has about a billion of through-holes of which diameter is around 200nm. This AAO membrane and the pellet of materials are stacked in the mold and pressed to mold after heating up to be melted. The AAO membrane is removed using KOH to obtain the molded nano hairs. As a result, the diameter of the molded hairs is around 200nm and the length is $2um{\sim}60um$ depending on the molding conditions and materials. The molded nano hair substrates is estimated to show much better adhesive characteristic than a substrate without nano hairs.

• Journal of Welding and Joining
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• v.26 no.1
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• pp.56-62
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• 2008

In this paper, elastic and plastic adhesion index was very important in deciding adhesive characteristics and varying elastic and plastic index, dimensionless load and pull-off force were analyzed and simulated. Finally, using AFM, experimental surface roughness parameters of substrates and pull-off force between tip and substrates were produced. Using these values, pull-off forces were calculated and were compared with experimental pull-off forces. Through simulation and experiment, it was found that interaction of asperity also had very important influence on adhesive contact.

• 전자공학회논문지 IE
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• v.44 no.3
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• pp.42-50
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• 2007

In this paper, elastic and plastic adhesion index was very important in deciding adhesive characteristics and varying elastic and plastic index, dimensionless load and pull-off force were analyzed and simulated. Finally, using AFM, experimental surface roughness parameters of substrates and pull-off force between tip and substrates were produced. Using these values, pull-off forces were calculated and were compared with experimental pull-off forces. Through simulation and experiment, it was found that interaction of asperity also had very important influence on adhesive contact.

• Animal cells and systems
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• v.16 no.6
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• pp.479-487
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• 2012

Biological attachment device is optimized in insect legs for attachment onto the variety of natural substrate. We have studied the microstructural characteristics of the tarsal appendages in the ladybug Harmonia axyridis using scanning electron microscopy to reveal the attachment system of their legs. The attachment devices are composed of claws and adhesive pads. The claws are connected with pretarsal segment, and their apical diverged hooks are developed to hold rough substrates. In contrast, the adhesive pads have an adhesive function onto smooth surface. The pads are interspersed at the ventral part of each tarsomere, and are composed of two kinds of hairy setae. The discoid tip seta (DtS) has a spoon-shaped endplate usually with a rounded concave structure, whereas the pointed tip seta (PtS) has a pointed tip, usually with a hooked endplate. While the PtS is broadly localized concentrically on the marginal area of both the proximal and distal pads, the DtS can be seen at the central areas of each adhesive pad except for the hind legs. Our findings demonstrate the presence of the direction-dependence pattern of the fibrillar system as well as a functional modification of the tenent setae to achieve proper contact with almost any kind of substrates.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.2
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• pp.215-223
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• 2019

A high temperature adhesive development which is crosslinked in low temperature is necessary for aerospace application because of thermal expansion mismatches of various substrates. For this purpose, we have designed and fabricated several formulations with high temperature epoxy resins, crosslinkers and additives considering various working conditions and high service temperature. As a result, some formulations showed higher adhesive strengths than Hysol EA 9394/C2 which is widely used for aerospace applications. We also have studied and summarized the mechanical properties of the best development adhesive in both room and high temperatures.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1580-1581
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• 2008

We investigated the effects of intermittent hydrostatic pressure with various duration of resting period on changes in calcium ($Ca^{2+}$) concentration and adhesive forces of cells on substrates. The quantitive adhesive forces of cells were measured under various resting periods. When the pressure applied to the cells, the concentration of $Ca^{2+}$ increased. Under intermittent hydrostatic pressure, the concentration of $Ca^{2+}$ was maintained under a resting period of 15 min, while it was not decreased with other resting periods of less than 15 min. With a resting period of 15 min, the magnitudes of adhesive forces were significantly increase. In addition, the adhesive forces were measured with and without $Ca^{2+}$ chelating agents to evaluate the effect of $Ca^{2+}$ on cell adhesiveness. When $Ca^{2+}$ ions were chelated, the adhesive forces dramatically decreased, even under intermittent hydrostatic pressure. We conclude that $Ca^{2+}$ plays an crucial role in modulating the adhesive forces of cells, and that the concentration of $Ca^{2+}$ can be increased by intermittent hydrostatic stimuli.

• Journal of Adhesion and Interface
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• v.5 no.2
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• pp.31-42
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• 2004

Many animals possess on their legs adhesive pads, which have undergone evolutionary optimization to be able to attach to variable substrates and to control adhesive forces during locomotion. Insect adhesive pads are either relatively smooth or densely covered with specialized adhesive hairs. Theoretical models predict that adhesion can be increased by splitting the contact zone into many microscopic, elastic subunits, which provides a functional explanation for the widespread 'hairy' design. In many hairy and all smooth attachment systems, the adhesive contact is mediated by a thin film of liquid secretion between the cuticle and the substrate. By using interference reflection microscopy (IRM), the thickness and viscosity of the secretion film was estimated in Weaver ants (Oecophylla smaragdina). 'Footprint' droplets deposited on glass are hydrophobic and form low contact angles. IRM of insect pads in contact showed that the adhesive liquid is an emulsion consisting of hydrophilic, volatile droplets dispersed in a persistent, hydrophobic phase. I tested predictions derived from film thickness and viscosity by measuring friction forces of Weaver ants on a smooth substrate. The measured friction forces were much greater than expected assuming a homogenous film between the pad and the surface. The findings indicate that the rubbery pad cuticle directly interacts with the substrate. To achieve intimate contact between the cuticle and the surface, secretion must drain away, which may be facilitated by microfolds on the surface of smooth insect pads. I propose a combined wet adhesion/rubber friction model of insect surface attachment that explains both the presence of a significant static friction component and the velocity-dependence of sliding friction.