• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.353.2-353.2
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• 2016

We studied electrochemical detection of Botulinum neurotoxin, Vaccinia virus, and Streptococcus Pneumoniae based on nanogap device. Target bio substances were employed as representative targets of protein, virus, and bacteria, respectively. Redox current generated by ferri/ferrocyanide as an electroactive probe was enhanced according to gap distance which was controlled by surface-catalyzed chemical deposition. We found that enhanced electrochemical signal leads more sensitive signal changes according to selective interaction of target and its complementary elements on the electrode or gap area. In case of Botulinum neurotoxin, the redox signal showed a time-dependent increase due to cleavage of the immobilized peptide which blocked redox cycling. Redox cycling was also hindered by Vaccinia virus and Streptococcus Pneumoniae which were selectively immobilized in the gap area.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.1
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• pp.34-38
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• 2005

The finite element method is very flexible for new shapes and provides flux distribution, magnetomotive force, eddy currents, and torques. However, it requires lengthy computational time in order to achieve desired accuracy. The magnetic equivalent circuit method takes less computation time than the finite element method. Therefore, the finite element method is mainly used to confirm the completed design. The magnetic equivalent circuit method is convenient for complicated analysis of the transient state of the induction motor. The magnetic equivalent circuit method is restricted to only one direction of magnetic flux. In this paper, the construction elements (that is, stator iron, rotor iron, yoke, air gap, etc.) of the squirrel cage induction motor were represented by a flux tube and the air gap magnetomotive force was calculated by the magnetic equivalent circuit method. Starting transient torque and phase current of the squirrel cage induction motor were verified by the theoretical calculation and the experiment.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.50-57
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• 2010

Various installation faults may lie in fasteners in the construction of a direct-fixation track by the top-down method. At an extreme, they may cause excessive interaction between the train and track, compromise the running safety of the train, and cause damage to the track components. Therefore, the faults need to be kept within the allowable level through an investigation of their effects on the interactions between the train and track. In this study, the vertical dynamic stiffness of fasteners in installation faults was measured based on the dynamic stiffness test by means of an experimental apparatus that was devised to feasibly reproduce gap faults. This study proposes an effective analytical model for a train-track interaction system in which most elements, except the nonlinear wheel-rail contact and some components that behave bi-linearly, exhibit linear behavior. To investigate the effect of the behavior of fasteners in gap faults in a direct-fixation track on the vehicle and track, vehicle-track interaction analyses were carried out, targeting key review parameters such as the wheel load reduction factor, vertical rail displacement, rail bending stress, and mean stress of the elastomer. From the results, it was noted that the gap faults in the concrete bearing surface of a direct-fixation track need to be limited for the sake of the long-term durability of the elastomer than for the running safety of the train or the structural safety of the track.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.4
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• pp.667-676
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• 2002

Many studies on the finite element modeling for bolted joints have proceeded, but the structures with bolted joints are complicated in shape and it is difficult to find out the characteristics according to joint condition. Usually, experimental methods have been used for bolted joint analysis. A reliable and practical finite element modeling technique for structure with bolted joints is very important for engineers in industry. In this study, three kinds of model are presented; a detailed model, a practical model and a simple model. The detailed model is modeled by using 3-D solid element and gap element, and the practical model is modeled by using shell element (a portion of bolt head) and beam element (a portion of bolt body), the simple model is modeled by simplifying practical model without using gap elements. Among these models, the simple model has the least degree of freedom and show the effect of memory reduction of 59%, when compared with the detailed model.

• Journal of Information Science Theory and Practice
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• v.8 no.1
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• pp.6-19
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• 2020

When information professionals deal with other disciplines in the course of digital humanities projects, they often assume that they are dealing with 'needful users' who have an 'information gap' to fill. This paper argues that the traditional view that information/knowledge is transferred from an information specialist donor to a domain specialist receiver is no longer appropriate in the digital humanities context, where the gap-and-search (or gap-and-filler) approach to information has given way to more direct, explorative engagement with information. The paper asks whether information science and the practising profession are ready for this paradigm shift and examines information science conservatism in two common collaboration scenarios, library support and digital development. It is shown that information science theory still assumes a traditional donor role in both scenarios. How information scientists deal with conservatism in practice is discussed in the example of the Prior project, in which the information science team exerted an ambiguous, hybrid approach with both conservative and non-conservative elements. Finally, two rather hypothetical answers are offered to the question of how information professionals should approach scholarly collaboration in the digital humanities context, where users have ceased to be supplicants. From a purely pragmatic perspective, information scientists need to shift their focus from information needs to research practices and the implications of these practices for digital information systems. More fundamentally, the emergence of digital humanities challenges information professionals to transform information systems designed for searching into digital objects that can be explored more freely by the digital humanities community.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.2
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• pp.78-85
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• 2012

Low-Voltage power lines should equip surge protection devices which protect electronic equipments and human lives against lightning and abnormal voltages. Data transmission capacity of the power line is determined by frequency characteristics of the surge protective devices. To analyze the effects of surge protective devices on the data transmission performance, various combinations of installation methods are tested which include ZnO varistor elements that is compatible with class I, class II and class III. The result claims that ZnO varistor for class III is found to be one of the main factors that deteriorates the transmission performance. To overcome this problem a serial connection methed between Gap type SPD and ZnO varistor is proposed. With the proposed scheme, laboratory experimental results show that the data transmission performance can be improved up to 91.9[%] with proper SPD combination.

• Journal of electromagnetic engineering and science
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• v.5 no.1
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• pp.43-47
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• 2005

Microwave or optical photonic band-gap(PBG) structures are conventionally realized by cascading distributive elements in a periodic pattern. However, the frequency bandwidth obtained through such plainly periodic arrangement is typically narrow, corporate with a relatively high rejection side-lobe band. To alleviate such problems, a design involving a chirping and tapering technique is hence introduced and employed. The design has been applied in both a planar stratified dielectric medium as well as a strip-line transmission line structure, and results are validated when compared with the corresponding conventional PBG structure.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.12 s.177
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• pp.163-169
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• 2005

Micro hole is ode of basic elements for micro device or micro parts. Micro electrochemical machining (ECM) can be applied to the machining of micro holes less than 50 ${\mu}m$ in diameter, which it is not easy to apply other techniques to. For the machining of passivating metals such as stainless steel, machining conditions should be chosen carefully to prevent a passive layer. The machining conditions also affect the machining resolution, In this paper, machining characteristics of micro ECM were investigated according to machining conditions such as electrolyte concentration and pulse conditions. From the investigation, optimal machining conditions were suggested for micro ECM of stainless steel.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1202-1205
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• 2005

Micro hole is one of basic elements for micro device or micro parts. By micro ECM, micro holes less than $50\mu{m}$ in diameter can be machined easily. Machining characteristics of micro ECM were investigated according to machining conditions such as electrolyte concentration and pulse conditions. From the investigation, optimal machining conditions were suggested for micro ECM of stainless steel. For the micro machining with high resolution, the change of machining gap should be predicted. By using electrochemical principle equations, the change of machining gap was simulated.

• Transactions of Materials Processing
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• v.15 no.5 s.86
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• pp.387-394
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• 2006

In order to see the effect of die deformation on the forming analysis of sheet metals, the draw-ins, strains, and spring-backs of an automotive fender panels are numerically simulated by considering the die deformation found by the simultaneous structural analysis of press and dies. By coupling the forming analysis and the structural analysis, the die deformation is simultaneously taken into account in the forming process. Furthermore, for the consideration of load difference transferred among the upper die, punch, and blank holder due to the changes in sheet thickness, the gap elements are employed instead of the blank sheet in the structural analysis. The numerical simulation results of an automotive finder draw panel are compared with the measurements. The comparison of the forming and spring-back analysis results between the rigid die and the deformed die shows that the consideration of tool deformation can predict more accurately the forming and spring-back of sheet metals.