• Tunnel and Underground Space
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• v.20 no.5
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• pp.318-324
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• 2010

Dynamic properties of materials by shock loads such as rock blasting and earthquake are recently attracted in the design of aboveground and underground structures. The advance of measuring devices enables to obtain the whole histories of stress and strain in rock specimen of which the failure is completed in several hundred microseconds. The SHPB has been a popular and promising technique to study the dynamic behavior of rock. And the dynamic compressive, tensile and other test with this experiment system are planned to be Suggested Methods of ISRM. This technical paper is to introduced one study article which focuses the design of 3S (special shaped striker) to produce the half-sine wave to eliminate the problems of the rectangular wave. This article is also describing the advantage of half-sine incident wave and size effect of rock dynamic strength.

• Journal of The Korean Society of Integrative Medicine
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• v.8 no.1
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• pp.27-36
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• 2020

Purpose : The purpose of this study is to apply kinesiology taping and dynamic taping to subjects with ankle instability and to find out the change of static balance and dynamic balance ability and to use it more usefully in daily life. Methods : The subjects were based on 30 Cumberland Ankle Instability Tool questionnaire scores of 24 or less, and were randomly assigned to the kinesiology taping group (n=15) and the dynamic taping group (n=15) to change the static balance and dynamic balance before and after taping Measured. The eyes were closed for 30 seconds and the average balance was measured three times through the Wii balance board in static balance, and the balance ability was evaluated by measuring functional reach test and star excursion balance test in dynamic balance. Results : As a result, the static balance showed significant results in the dynamic speed and the moving distance in the dynamic taping group (p<.05). However, there was no significant difference in the shaking area and the difference in the kinesiology taping group (p<.05) However, both groups showed significant differences in dynamic balance (p<.05). Conclusion : It was confirmed that the application of taping was effective for static and dynamic balance in subjects with ankle instability, and the application of dynamic taping was more effective than kinesiology taping.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.533-534
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• 2010

• 한국항공운항학회:학술대회논문집
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• 2006.11a
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• pp.115-119
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• 2006

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1997.10a
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• pp.101-108
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• 1997

A pair of piezoelectric transducers was developed for geotechnical site characterization in rock materials. SH-wave measurement capability of the transducers can provide a more complete characterization. The performance of the transducers was tested at a limestone site.

• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.3
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• pp.244-252
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• 2015

This paper describes design and construction results of the measurement system developed on the purpose of measuring properties of AC magnetic field sensors used in the weapon system. The system for measuring the properties of AC magnetic field sensors consist of 3-axis helmholtz coil, signal generator, signal amplifier, sensor data acquisition unit and AC magnetic field sensor property measurement & analysis equipment including the operating software. By using this system, we can measure various properties of AC magnetic field sensor such as sensitivity, linearity and dynamic response in the frequency from 1 Hz to 10 kHz. Finally we also verified its performance by measuring the property of a MAG 639, standard magnetic field sensor of bartington instruments, with the developed measurement system.

• Journal of the Korean Geotechnical Society
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• v.21 no.1
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• pp.105-114
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• 2005

An in-hole seismic method, which has been developed for measuring dynamic properties of subsurface materials, was improved in terms of cost effectiveness and practicality. The upgraded features include the motorized triggering system rather than the manual prototype version in the previous studies and a connecting rod between source and receiver in the module. The probe, thus, can be used for the field measurements of soil properties as well as those of rocks. The performance of the probe has been evaluated through extensive cross-hole tests and in-hole tests at various sites.

• Journal of Chest Surgery
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• v.21 no.2
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• pp.223-230
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• 1988

Emax, end-systolic pressure-volume relationship, has been established as a new concept which can be representative of ventricular contractility itself since 1970s. Comparing to ejection fraction[EF], Emax is independent of preload and afterload. However Emax has not been proved precisely in non-thoracotomized condition because current methods have limitation in measuring ventricular chamber volume accurately in in viva state. The Dynamic Spatial Reconstructor[DSR], high speed computerized tomography, can measure ventricular chamber volume accurately throughout cardiac cycle in non-thoracotomized state. So Emax and EF of the left ventricle was tried to measure precisely in in vivo condition with DSR. Emax was compared to EF to estimate its ability to evaluate ventricular contractility. 5 mongrel dogs, weighing 15-16kg, were used for measuring Emax and EF of the left ventricle in 3 or 4 different loading conditions using DSR. Emax value in 5 dogs was from 2.62 to 10.49. Each dog has one Emax value regardless of loading conditions. However EF in 5 dogs varies depending on loading conditions. The conclusions are that Emax is useful in in viva state and EF varies depending on loading conditions. So Emax should be tried to use in clinical situation rather than EF because it is always representative of contractility itself regardless loading conditions in in viva state.

• Journal of the Korean Society of Visualization
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• v.9 no.4
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• pp.63-68
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• 2011

The flow-field of a liquid-metal system is very important for the safety analysis and the design of the steam generator of liquid-metal fast breeder reactor. Dynamic neutron radiography (DNR) is suitable for a visualization and measurement of a liquid metal flow and a two-phase flow in a metallic duct. However, the three dimensional DNR techniques is not enough to obtain the velocity information in the wide channel up to now. In this research, a high speed DNR technique was applied to visualize the heavy liquid-metal flow field in the narrow channel with the HANARO-beam facility. The images were taken with a high frame-rate neutron radiography at 250 fps and analyzed with a Particle Image Velocimetry(PIV) method. The images were compared with the results of the commercial CFX code to study the feasibility of DNR technique for the measuring the heavy liquid-metal flow field. The PIV images could discern the turbulent vortex flow in the two-dimensional narrow channel.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.634-637
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• 2004

This paper presents a Split Hopkinson Pressure Bar(SHPB) technique to obtain compressive stress-strain data for rubber materials. An experimental technique that modifies the conventional Split Hopkinson Pressure Bar(SHPB) has been developed for measuring the compressive stress-strain responses of materials with low mechanical impedance and low compressive strengths such as rubber. This paper introduces an all-polymeric pressure bar which achieves a closer impedance match between the pressure bar and the specimen materials. In addition, we are a pulse shaper to lengthen the rising time of the incident wave to ensure stress equilibrium and homogeneous deformation of a rubber materials. It is found that the modified technique can be determine the dynamic deformation behavior of an NBR rubber more accurately.