• Korean Journal of Materials Research
• /
• v.15 no.1
• /
• pp.6-13
• /
• 2005

Copper based leadframe sheets were immersed in two kinds of hot alkaline solutions to form brown-oxide or blackoxide layer on the surface. The oxide-coated leadframe sheets were molded with epoxy molding compound (EMC). After post mold curing, the oxide-coated EMC-leadframe joints were machined to form sandwiched double-cantilever beam (SDCB) specimens. The SDCB specimens were used to measure the fracture toughness of the EMC/leadframe interfaces under quasi-Mode I loading conditions. After fracture toughness testing, the fracture surface were analyzed by various equipment to investigate failure path. An adhesion model was suggested to explain the failure path formation. The adhesion model is based on the strengthening mechanism of fiber-reinforced composite. The present paper deals with the introduction of the adhesion model. The explanation of the failure path with the proposed adhesion model was introduced in the companion paper.

• Journal of Surface Science and Engineering
• /
• v.36 no.4
• /
• pp.347-355
• /
• 2003

Roughening of metal surfaces frequently enhances the adhesion strength of metals to polymers by mechanical interlocking. When a failure occurs at a roughened metal/polymer interface, the failure prone to be cohesive. In a previous work, an adhesion study on a roughened metal (oxidized copper-based leadframe)/polymer (Epoxy Molding Compound, EMC) interface was carried out, and the correlation between adhesion strength and failure path was investigated. In the present work, an attempt to interpret the failure path was made under the assumption that microvoids are formed in the EMC as well as near the roots of the CuO needles during compression-molding process. A simple adhesion model developed from the theory of fiber reinforcement of composite materials was introduced to explain the adhesion behavior of the oxidized copper-based leadframe/EMC interface and failure path. It is believed that this adhesion model can be used to explain the adhesion behavior of other similarly roughened metal/polymer interfaces.

• Journal of Practical Engineering Education
• /
• v.15 no.2
• /
• pp.419-427
• /
• 2023

In this study, optimal adhesion conditions to alleviate defects caused by heat shrinkage with FDM type 3D printers with machine learning are researched. Machine learning is one of the "statistical methods of extracting the law from data" and can be classified as supervised learning, unsupervised learning and reinforcement learning. Among them, a function model for adhesion between the bed and the output is presented using supervised learning specialized for optimization, which can be expected to reduce output defects with FDM type 3D printers by deriving conditions for optimum adhesion between the bed and the output. Machine learning codes prepared using Python generate a function model that predicts the effect of operating variables on adhesion using data obtained through adhesion testing. The adhesion prediction data and verification data have been shown to be very consistent, and the potential of this method is explained by conclusions.

• Proceedings of the KIEE Conference
• /
• 1998.11a
• /
• pp.347-349
• /
• 1998

This paper describes a fuzzy identification model for slip - adhesion curve of High - speed trains. The model has fuzzy inputs corresponding to rail condition and crisp inputs for train. Nonlinear function is obtained by using fuzzy outputs. Finally slip - adhesion curve is given by the function. First, Results are presented of slip - adhesion curves under the influence of changing rail condition. Second, Dynamic moving simulation by proposed fuzzy slip - adhesion model is presented. Simulation results show fine characteristics.

• YAKHAK HOEJI
• /
• v.53 no.3
• /
• pp.119-124
• /
• 2009

Cell-cell adhesion managed by various adhesion molecules plays an important role in regulating functional activation of cells. This event mediates attachment of inflammatory cells to endothelial cells, interaction of antigen-presenting cells with T cells and metastatic adherence of cancer cells to epithelial tissue cells. Therefore, this cellular response is considered as one of therapeutic target to treat various cancers and inflammatory diseases. To develop proper model for evaluation of functional activation of adhesion molecules, the ability of U937 and Jurkat T cells responsive to various adhesion inducers such as phorbal-12-myristate-13-acetate (PMA), staurosporin and monoclonal antibodies to CD29, CD43 and CD98 was investigated using quantitative cell-cell adhesion assay. U937 cells made more cell-cell clusters by the treatment of antibodies to CD29 and CD43 than Jurkat T cells, while Jurkat T cells exhibited increased cell-cell adhesion ability in CD98 antibody treatment. In agreement, the surface levels of CD29 and CD98 were highly observed in U937 and Jurkat T cells, respectively. Therefore, our data suggest that Jurkat T and U937 cells can be used for model system to evaluate functional activation of adhesion molecules such as CD29 and CD98.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 1993.10a
• /
• pp.1176-1185
• /
• 1993

The purpose of this study is to propose a new dynamic model of wheels and agricultural tractors through verification of the existence of " lift resistance " and "perpendicular adhesion" which also can be called " contra-retractive adhesion". The existence of these forces was proved through experiments including the development of a sensor which can measure the forces acting on a wheel accurately. Consequently " perpendicular adhesion ratio" which is defined as the ratio of the perpendicular adhesion to the distributed load was observed to be in the range of 0.05 to 0.3. This means the influence of the " lift resistance " is comparable to that of motion resistance in wheel dynamics. The perpendicular adhesion ratio was observed to decrease logarithmically with the increase of ground contact pressure, and to increase linearly with increase of the travel speed of the wheel . Some examples to express the new dynamic model compared to the conventional dynamics are explained.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.54 no.1
• /
• pp.48-55
• /
• 2005

Mobility of an indoor wheeled robot is affected by adhesion force that is related to various floor conditions. When the adhesion force between driving wheels and floor decreases suddenly, the robot begins slip. In order to overcome this slip problem, optimal slip velocity must be decided for stable movement of wheeled robot. First of all, this paper shows that conventional PI control can not be applied to a wheeled robot of the light weight. Secondly, proposed fuzzy logic is applied to the Takagi-Sugeno model for the configuration of fuzzy sets. For the design of Takagi-Sugeno model and fuzzy rule, proposed algorithm uses FCM(Fuzzy c-mean clustering method) algorithm. In additionally, this algorithm adjusts the driving torque for restraining re-slip. The proposed fuzzy logic controller(FLC) is pretty useful with prevention of the slip phenomena for the controller performance in the re-adhesion control strategy, These procedures are implemented using a Pioneer 2-DXE wheeled robot parameter.

• Journal of Korean Neurosurgical Society
• /
• v.49 no.6
• /
• pp.323-328
• /
• 2011

Objective : Epidural fibrosis and adhesion are the main reasons for post-laminectomy sustained pain and functional disability. In this study, the authors investigate the effect of irradiated freeze-dried human amniotic membrane on reducing epidural adhesion after laminectomy on a rat model. Methods : A total of 20 rats were divided into two groups. The group A did not receive human amniotic membrane implantation after laminectomy and group B underwent human amniotic membrane implantation after laminectomy. Gross and microscopic findings were evaluated and compared at postoperative 1, 3 and 8 weeks. Results : The amount of scar tissue and tenacity were reduced grossly in group of rats with human amniotic membrane implantation (group B). On a microscopic evaluation, there were less inflammatory cell infiltration and fibroblast proliferation in group B. Conclusion : This experimental study shows that implantation of irradiated freeze-dried human amniotic membrane reduce epidural fibrosis and adhesion after spinal laminectomy in a rat model.

• Proceedings of the KIEE Conference
• /
• 2005.05a
• /
• pp.30-32
• /
• 2005

Mobility of an indoor wheeled robot is affected by adhesion force that is related to various floor conditions. When the adhesion force between driving wheels and floor decreases suddenly, the robot begins slip. In order to overcome this slip problem, optimal slip velocity must be decided for stable movement of wheeled robot. First of all, this paper shows that conventional PI control can not be applied to a wheeled robot of the light weight. Secondly, proposed fuzzy logic is applied to the Takagi-Sugeno model for the configuration of fuzzy sets. For the design of Takagi-Sugeno model and fuzzy rule, proposed algorithm uses FCM(Fuzzy c-mean clustering method) algorithm. The proposed fuzzy logic controller(FLC) is pretty useful with prevention of the slip phenomena for the controller performance in the re-adhesion control strategy.

• Archives of Plastic Surgery
• /
• v.37 no.4
• /
• pp.329-334
• /
• 2010

Purpose: Adhesion after flexor tendon injury is a result of fibrosis between tendon and tendon sheath. This, finally interfere with gliding mechanism of tendon and results in functional problem of hands. Therefore, there have been many trials to reduce adhesion around the tendon. However, there is no standard procedure clinically practiced in hospitals. Mitomycin-C is an antineoplastic alkylating agent that decrease fibroblast proliferation and scar formation. It is commonly used in many surgery to reduce postoperative adhesion. This study was designed to observe the effect of Mitomycin-C on preventing adhesion in injured flexor tendon. Methods: The deep flexor tendon of digit 2 and 4 in the left forepaw of 15 New Zealand White rabbits were subjected to partial tenotomy. In study group, injury site was exposed to a single 5-minute application of Mitomycin-C, and in control group was left untreated. Digit 2 and 4 in the right forepaw of each rabbit were considered as nonadhesion control group. After 2 weeks, the animals were sacrificed and digits were amputated for biomechanical test and histological study. Results: In biomechanical study to measure yield point, mean yield point of non-adhesion control was $17.43{\pm}2.33$ and $25.07{\pm}4.03$ for adhesion control, which proves increase of adhesion in adhesion control group (p<0.05) in 95% confidence. In Mitomycin-C group, mean yield point was $12.71{\pm}4.97$. Compared with adhesion control, there was decrease in adhesiveness in Mitomycin-C group (p<0.05) in 95% confidence. In histological study, the result of adhesion control revealed massive adhesions of bony structure, fibrotic tissue and tendon structure with ablation of the border. However in Mitomycin-C group, we could find increased fibrotic tissue, but adhesion is much lesser than adhesion group and borders between structures remain intact. Conclusion: This study suggests that Mitomycin-C can significantly reduce adhesion of injured flexor tendon in rabbit model.