• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.4
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• pp.592-598
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• 2000

The existin Berenger's PML(Perfectly Matched Layer) cannot absorb evanescent modes effectively generated in waveguides or periodic array structures. Although some absorbing boundary conditons(ABC) were introduced to absorp the evanescent modes, they did not show sufficient performance or could not be applied easily because of their much difference from Berengers PML. In this paper, NPML(New PML) is introduced to absorb the evanescent modes by splitting the conductivity and permittivity profile of the Berengers PML. The proposed NPML is certified as an ABC having enough performance for evanescent and propagating modes by analyzing the global error and the reflectivity of a waveguide.

• Proceedings of the KSR Conference
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• 1998.05a
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• pp.377-384
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• 1998

The crushable front part of the conventional TGV is composed of 3 energy absorption zones; retractable coupler, protective headstock and honeycomb structure. This frontal part must absorb about 80% of the energy that should be done in a cra shworthy design. The conventional TGV can absorb 2MJ impact energy by the frontal end, but 5MJ is the design target for energy absorption in the next generation TGV. To accomplish this design goal, a new concept of design is necessary for energy absorbing components. In this paper, the design concept of the tube expansion energy absorber will be proposed and analyzed. The crash analysis of the energy absorber are performed by comparing the value of the theoretical equation wi th the simulation calculated from the commercial nonlinear FE-Code ‘PAM-CRASH’ S/W.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.10
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• pp.177-182
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• 2003

The front-end side members of automobiles absorb most of the energy in a case of front-end collision. The front-end side members are required to have a high stiffness together with easiness to collapse sequentially to absorb more impact energy. The axial static collapse test (5mm/min) was conducted by using UTM for form different types of members which have different cross section shapes; single hat, single cap, double cap, and double hat. The single hat shaped section member has the typical standard section, which the double hat shape section has a symmetry in the center to have more stiffness. As a result of the test, the energy absorbing characteristic was analyzed for different section shapes. It turned out that the change of section shape influence the absorbing energy, the mean collapse load and the maximum collapse load, and the relation between the change of section shape and the collapse mode.

• Journal of Powder Materials
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• v.27 no.4
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• pp.287-292
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• 2020

The subject of this study is a zeolite generated as a by-product of recycling LAS (lithium-aluminum-silicate) resources, a kind of glass and ceramic produced by induction. The zeolite by-product is modified into Mg-zeolite using Mg as a cation to absorb Pb, a heavy metal generated from water pollution caused by recent industrial wastewater. An ion-exchange method is used to carry out the modification process, from zeolite byproduct to Mg-zeolite, and simultaneously absorb the Pb in the heavy-metal solution (99.032 mg/L). It is found that the sodium zeolite in the raw material residue can be modified to magnesium zeolite by reacting it with a mixture solution at 1 M concentration for 24 h. As a result, it is found that the residual Pb (0.130 mg/L) in the heavy metal solution is shown to be absorbed by 99.86%, with successful formation of a Mg-modified zeolite.

• Journal of the Society of Disaster Information
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• v.6 no.1
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• pp.78-90
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• 2010

Exposure to the outside, the concrete is differential moisture distribution depending on the depth. Such a differential moisture distribution causes the differential drying shrinkage in concrete structures. This thesis is researched to compare the shrinkage of lightweight concrete depending on depth to normal concrete. It is used artificial lightweight aggregate which has 20% of pre-absorb value by lightweight concrete. When water-binder ratio is 30%, average shrinkage of lightweight concrete section decreased than normal concrete, but differential shrinkage of lightweight concrete section increased. However water-binder ratio is 40% and 50% average shrinkage and differential shrinkage of lightweight concrete section decreased than normal concrete.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.16 no.1
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• pp.1-6
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• 2008

Role of landing gear is to absorb energy which is generated by aircraft ground maneuvering and landing. Generally, in order to absorb the impact energy, oleo-pneumatic type shock absorber is used in aircraft landing gear. Oleo-pneumatic type shock absorber has a good energy absorption efficiency and is light in weight because structure of oleo-pneumatic type shock strut is relatively simple. In this study, dynamic load analysis for swinging arm type landing gear was performed to predict landing loads. Modeling of landing gear was conducted with MSC.ADAMS, and dynamic landing loads were analyzed based on ADS-29. Optimum landing loads were generated through adjustment of damping orifice and the analysis results were presented with various aircraft attitude.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.178-179
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• 2021

Comparing the absorption volume of test pieces immersed over time in room temperature moisture with weight, WF absorbed about 40% more than PLAIN, and PLAIN stopped absorbing after 10 minutes, but WF continued to absorb. It is thought that the woven fabric layer of the core material continued to absorb moisture. In the heat transfer test, the test piece to which only WF was applied had a temperature difference of about 2℃ compared to PLAIN, and when the insulating liquid was sprayed, there was a difference in heat transfer properties of up to 5℃. This is judged to have low heat transfer properties of the basic woven fabric, but the heat insulating liquid also further reduces heat transfer properties.

• Proceedings of the Korea Contents Association Conference
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• 2006.11a
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• pp.849-852
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• 2006

In this research electromagnetic waves in interception and that do so that keep in step in trend that develop material that draw water by sucking and material that can absorb electromagnetic waves use and do goods anger focus. Character that electromagnetic waves use and make material that can absorb electromagnetic waves to be happened much in portable phone for instance using sticking on hand phone bar Terry part electromagnetic waves intercept wish to. Wish to study character that can conglutinate by evil worldly affairs reason combined us introducing character concept beside function originally electromagnetic waves interception and use region that intercept this time. Because character application process executes question investigation, design preference degree reflects the highest thing and arranged to conclusion.

• Korean Journal of Applied Biomechanics
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• v.13 no.3
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• pp.311-325
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• 2003

A relation between the movement range of arms and arising moment has been studied to find out efficient movement range to minimize impact concerning arm landing in sports aerobics. Four male athletes who won top three in national-level sports aerobics competition were chosen for the experiment. They were allowed to jump in between two force platform so that the right hand and the right leg could land onto the front and rear force platform, respectively. The sampling frequency was 200 Hz. The main conclusions based on the analysis of the angle and joint moment parameters of wrist, elbow, and shoulder are as follows: 1. The wrist moment was small when its angle was small, indicating that the dorsi-flexion of the wrist joint offered a positive influence to reduce wrist moment. 2. The elbow angle increased as wrist angle decreased and vice versa. This means that the movement range of the wrist joint affects that of the elbow joint. The darsi-flexion of the wrist is the position to absorb the impact of the elbow effectively rather than to absorb the impact of the wrist itself. The impact is absorbed by the flexion of wrist joint rather than the wrist. 3. The degree of moment transfer of the shoulder joint, having absorbed the impact from the elbow and elbow joint, became dependent on the efficiency of the fore-joints impact absorption.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.7
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• pp.120-126
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• 2001

The widely used spot welded section members of vehicles are structures which absorb most of the energy in a front-end collision. In front-end collision, sufficiently absorbed in the front parts, the impact energy does not reach the passengers. Simultaneously, the frame gets less damaged. This structures have to be very stiff, but collapse progressively to absorb the kinetic energy as expected. In the view of stiffness, the double-hat shaped section member is stiffer than the hat shaped section member. In progress of collapse, the hat shaped section member is collapsing progressively, but the double-hat shaped section member does not due to stiffness. An analysis on the hat shaped section member was previously completed. This paper concerns the collapse characteristic of the double-hat shaped section member. In the program system presented in this study, an explicit finite element code, LS-DYNA3D is adopted for simulating complicate collapse behavior of double hat shaped section members with respect to spot weld pitches. And comparing with the results from the quasi-static and impact experiment, the simulation has been verified.