• The Journal of the Korean dental association
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• v.19 no.4 s.143
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• pp.347-352
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• 1981

This experiment was performed to estimate the changes on blood flow of the oral structures in hemorrhagic shock. Rabbits were anesthetized by intravenous injection of nembutal(30mg/kg). The Femoral artery was exposed and cannulated with polyethylene tubing filled with heparinized saline. Hypovolemic shock was induced by collecting the bloos of which amount was equaled as 2 % of body weight through arterial cannula for about 30 minutes. During hemorrhage, arterial blood pressure was recorded on recorder. In hypovolemic shock, arterial blood pressure decreased from 116.2±4.1 mmHg to 62.6±4.0 mmHg. Distribution of blood flow in oral tissues decreased to 30-50 % of control group. But blood flow of the masseter muscle was increased and the mandibular angle was not changed.

• Journal of the Korea Institute of Military Science and Technology
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• v.7 no.2 s.17
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• pp.118-125
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• 2004

In anti-ship missile, the seeker and guidance control units are located in front of warhead. When the missile hits target, these structures play an important role to warhead structure like a shock absorber Because the shock waves are attenuated, the survival probability of warhead increases which guarantees the explosive train. In this thesis the role of frontal sections is studies. The theoretical analysis and numerical analyses using LS-DYNA code are performed. To prove the effect of shock absorber, the penetration test using subscale prototype warhead are executed.

• 한국전산유체공학회:학술대회논문집
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• 2005.04a
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• pp.213-218
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• 2005

The purpose of this study is the characteristics of an innovative inlet system with shock/boundary layer interactions by using various types of bumps which are substituted for the conventional bleeding system in supersonic inlet. This study performs a comprehensive numerical effort that be directed at better understanding the three-dimensional flowfield includes shock/boundary layer interaction and growth of turbulent boundary layer that occur around a three-dimensional bump in a supersonic inlet. The characteristics of boundary layer seen in the current numerical simulations indicates the potential capability of the three-dimensional bump to control shock/boundary layer interaction in supersonic inlets.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.2
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• pp.18-25
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• 2007

Computational study on the passive control of the oblique shock-wave/turbulent boundary-layer interaction utilizing slotted plates over a cavity has been carried out. The numerical boundary layer profile upstream of the interaction follows the compressible turbulent boundary-layer theory reasonably well, and the other results also show good agreements with the experimental observations, such as the wall surface pressures and Schlieren flow visualizations. Further, the effects of various slot configuration including number, location and angle of the slots on the characteristics of the interactions, such as the variation of the total pressures, the boundary-layer characteristics downstream of the interaction and the recirculating mass flux through the slots, are also tested and compared.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.5
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• pp.305-312
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• 2018

DC distribution systems has recently taken the spotlight. Concerns over human safety and stability facility are raised in DC distribution systems. Std. IEC 60479 provides basic guidance on "the effects of shock current on human beings and livestock" for use in the establishment of electrical safety requirements and suggests an electrical impedance of the human body. This study analyzes impedance spectrums based on the electrical equivalent impedance circuit for the human body; human body impedances measured by experiments are analyzed below the fundamental frequency (60 Hz). The analysis shows that the equivalent impedance circuit for the human body should be modified at least in low-frequency range below the fundamental frequency (60 Hz). The DC residual current detection method that can classify electric shock accidents of humans and electric leakages of facilities is proposed by applying the analysis result. The detection method is verified by experiments on livestock.

• Korean Journal of Applied Biomechanics
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• v.25 no.3
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• pp.283-291
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• 2015

Objective : The purpose of this study was to determine the differences in the head and tibial acceleration signal magnitudes, and their powers and shock attenuations between flat-footed and normal-footed running. Methods : Ten flat-footed and ten normal-footed subjects ran barefoot on a treadmill with a force plate at 3.22m/s averaged from their preferred running speed using heel-toe running pattern while the head and tibial acceleration in the vertical axis data was collected. The accelerometers were sampled at 2000 Hz and voltage was set at 100 mv, respectively. The peak magnitudes of the head and tibial acceleration signals in time domain were calculated. The power spectral density(PSD) of each signal in the frequency domain was also calculated. In addition to that, shock attenuation was calculated by a transfer function of the head PSD relative to the tibia PSD. A one-way analysis of variance was used to determine the difference in time and frequency domain acceleration variables between the flat-footed and normal-footed groups running. Results : Peaks of the head and tibial acceleration signals were significantly greater during flat-footed group running than normal-footed group running(p<.05). PSDs of the tibial acceleration signal in the lower and higher frequency range were significantly greater during flat-footed running(p<.05), but PSDs of the head acceleration signal were not statistically different between the two groups. Flat-footed group running resulted in significantly greater shock attenuation for the higher frequency ranges compared with normal-footed group running(p<.05). Conclusion : The difference in impact shock magnitude and frequency content between flat-footed and normal-footed group during running suggested that the body had different ability to control impact shock from acceleration. It might be conjectured that flat-footed running was more vulnerable to potential injury than normal-footed running from an impact shock point of view.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.5
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• pp.110-120
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• 1994

Due to the increasing demands in comfortable drivability, most motor companies are developing their own unique shift controller to suppress the shift shock induced by gear change. For a typical automatic transmission system, the dynamic constraints of friction clutch was clarified for efficient program development and major factors effecting the shift transient was confirmed by simulation study. The MIMO LQG/LTR controller was designed to control the turbine and corresponding gear speed. By establishing the control strategy recalling transient response during shift the speed controller mentioned above was used as an indirect torque controller. Consequently a new concept for a systematic design method of shift controller applicable to wide-varying systems was suggested which is time efficient and cost efficient saving a lot of experimental study.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.6
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• pp.649-659
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• 2016

This paper describes control algorithm and control structure of vehicle control unit for range-extended electric vehicle equipped with engine-generator system, and specially presents methods which determine optimal operating points and decreases a vibration or a shock for operating the engine-generating system. The vehicle control algorithm is consisted of several parts which are sequence control, calculation of wheel demand torque, determination of operating points, and management of operating points and so vehicle controller has be made possible to efficiently manage calibration parameters. The control algorithm is evaluated by driving test modes, launching performance and operating engine-generator system and so on. In conclusion, this paper present methods for extending a mileage, improving a launching performance and reducing vibration or shock when the engine-generating system is starting or is stopping.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.4
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• pp.130-141
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• 1997

Work on the reduction of particulate matter(PM) from a diesel vehicl has led to a new trp system and a control method to control the combustion rate of the PM filtrated in the trap, which was named as 'Active Exhaust Feeding Regeneration(AEFR) System' by its operation mechanism. Ceramic cordierite filter is a major component of the trap and susceptible to thermal shock. Therefore the system should be designed to reduce the peak temperature and temperature gradients in the trap ; these have been considered to be the main factors causing thermal shock of the filter during the regeneration. It uses the engine's exhaust gas partially for the regeneration of the ceramic filter. It controlled bypass flow rate of the engine's exhaust gas precisely to control the temperature of the gas entrained into the filter. Gas temperatures were measured inside filter, and the oxygen concentration at the outlet of the filter was also monitored during the regeneration to analyze the combustion process of the PM. The temperature distributions and temperature gradients in the filter during the regeneration varied widely according to the regeneration control schemes. Finally, this system shows relatively low peak temperature and temperature gradients in the filter during its regeneration. It is considered that this system uses a mew method to control the combustion rate of the PM, which is different from the methods used in the previous studies.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.2
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• pp.192-196
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• 2005

A study was conducted to monitor the changes in serum protein profile, cholesterol and blood glucose during endotoxic shock in buffalo calves and also to assess the role of prophylactic supplementation of vitamin E and selenium in alleviating the endotoxic effects. Fifteen male buffalo calves (6-8 months of age) were divided into three groups: Group I (control)-infused with 0.9% saline solution; Group II-infused with E. coli endotoxin at 5${\mu}g/kg$ body weight in normal saline solution; Group III- supplemented prophylactically with 250 mg vitamin E and 7.5 mg selenium by i/m injections at weekly intervals for one month prior to the induction of endotoxic shock. The blood samples were collected at 0, 1, 3, 6, 9, 12, 24, 48 and 72 h after the induction of shock. Endotoxin caused a significant (p<0.05) hypoproteinemia from 3-12 h post infusion in group II but this hypoproteinemia was less pronounced and only from 3-9 h post infusion in vitamin E and selenium supplemented calves. Hypoglycemia was observed in group II from 3-24 h and blood glucose level returned to normal at 72 h. However hypoglycemia was mild in group III and blood glucose returned to normal at 48h. Hypocholesterolaemia and hypoalbuminemia were found in both groups II and III but these changes were less pronounced in group III i.e. vitamin E and Se supplemented calves. Serum electrophoretic protein patterns of group III were quite similar to those of control group but animals of group II had different electrophoretic pattern. It was concluded that the antioxidant effects of vitamin E and Se prevent the liver against oxidative stress during endotoxic shock.