• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.2
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• pp.69-75
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• 2007

So far, anti-piercing depths for concrete slabs have been determined using Conventional Weapon's Effects Program(CONWEP) that was developed by the U. S. Army's Corps of Engineering. However, it has been suggested by a number of field officers that the values computed by CONWEP tend to be too high for protective facilities used in small military units and that indiscriminate application of these values to such facilities would lead to uneconomical penetration-proof designs. In this study, gunshots onto RC slabs were carried out using KM80 bullets in order to measure the piercing depths. The observed depths and the depths offered by the CONWEP system differed greatly from each other by up to 119 centimeters. Based on the depth values obtained through this experiment, we have proposed a new equation to calculate effective anti-piercing depths for RC slabs against small caliber bullets.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.35-36
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• 2019

Major influence factors for piercing depth of concrete against small caliber bullet are target's property such as compression strength of concrete and bullet's property such as the velocity and weight of it. In particular about the bullet's property, velocity and incidence angle could be controlled by specific position or distance between targets and shooter, but the angle of yaw of bullet dose not. Because the the angle of yaw of bullet causes lower piercing force of bullet, some errors on piercing depth of concrete could be appeared by live fire test for the evaluation of protective performance. Therefore, we have checked the error canceling effect on the piercing depth of concrete by single shot and barrage of small caiber bullets. As a result, we identified that the error of piercing depth by the angle of yaw of bullet could be cancelled by barrage.

• Tuberculosis and Respiratory Diseases
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• v.67 no.1
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• pp.27-31
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• 2009

Background: The large caliber catheter used in the treatment of pneumothorax causes great damage to the chest wall and organs. The purpose of this study was to prove that the use of a smaller caliber catheter is effective in treating pneumothorax with decreasing admission period and that the recurrence rate of spontaneous pneumothorax is low. Methods: Patients who had been admitted for treatment of first time occurrence of pneumothorax between May, 2004 and December, 2008 were included in the study. The caliber of catheter used this study is 18 Guage (1.2mm). The efficacy of treatment, admission period and recurrence rate of treating pneumothorax with small caliber catheter were compared to the control group using a tube thoracostomy for treatment. Results: The admission period for primary spontaneous pneumothorax was 10.8$\pm$3.6 days for the group (n=68) using tube thoracostomy compared to 4.5$\pm$1.3 days for the group (n=31) using the small caliber catheter (p<0.05). There was no statistically significant difference in recurrence rate between the two groups. Conclusion: The use of a smaller caliber catheter for the treatment of pneumothorax reduces the admission period without a significant increase in recurrence rates.

• Journal of Korean Neurosurgical Society
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• v.53 no.4
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• pp.241-244
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• 2013

The authors describe the use of a self-expandable stent in a temporary deployment for treatment of a very wide-neck A1 segment of anterior cerebral artery (ACA) aneurysm following incomplete clipping. A 39-year-old hypertensive man presenting with seizure-like movement underwent computed tomography, which showed acute subarachnoid hemorrhage and an A1 segment of ACA aneurysm with superior and inferior projection. He underwent surgical clipping of the aneurysm, but superior and posterior portion of wide-neck aneurysm remained. We decided to treat the remnant aneurysm using an endovascular modality. After selection of the aneurysm, coil packing was performed assisted by the temporary semi-jailing technique. The Enterprise stent (Cordis Neurovascular, Miami, FL, USA) was deployed and recaptured repeatedly for angiography to ensure safety of the small caliber parent artery. Successful semi-deployment and recapture of the stent allowed subtotal coil occlusion of the aneurysm with good anatomic and clinical results. No complications were encountered. The stent could be recaptured up to the point where the proximal end of the stent marker was aligned with distal marker band of the microcatheter, approximately 70% of the stent length. The temporary semi-jailing technique is feasible for wide-neck aneurysm with small caliber parent artery.

• Journal of Power System Engineering
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• v.18 no.5
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• pp.144-149
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• 2014

The silencer of 155mm caliber howitzer is developed to reduce its firing loud noise. This kind of research of a large gun was seldom because its big firing noise does not make significant effect even if to use silencer. Nowadays, military facilities became closely located civilian residential area. The noise would be regarded environmental pollution. So the noise reducing research becomes reconsidered. The previous silencer researches were only dealt with small guns as pistols and rifles moreover their theories was not properly analyzed for a large caliber silencer. The reason was previous researches of a large caliber silencer as 155mm howitzer were limited because their data based on simulation results without actual test by using computational fluid dynamics. In this study, the entire processes of silencer of 155mm caliber howitzer which were design, manufacturing, actual firing test, and analysis of its theories, were performed and showed. In particular, the actual noise of with silencer and without was measured and the results were compared to analyze the effect of silencer.

• Journal of Chest Surgery
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• v.51 no.6
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• pp.423-426
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• 2018

This study determined the feasibility of the cuff technique for small-caliber vascular grafts in a rat model. A graft was implanted with the cuff technique or suture technique in a 1-cm segment of the abdominal aorta in 12 rats. The mean aortic clamp time was 29 minutes with the cuff technique and 44 minutes with the suture technique; the cuff technique was significantly shorter. Abdominal angiography at 1 week after implantation showed no significant stenosis in 9 rats, focal stenosis of the mid-portion of the graft in 1 rat with each technique, and total occlusion of the graft in 1 rat with the suture technique. We have successfully used the cuff technique for anastomosis for small-caliber vascular grafts in an animal model.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.5
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• pp.578-583
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• 2016

In order to provide a basis data for design of small arms and their silencer, an experimental study on firing noise of small arms was performed around the muzzle of a gun. For this experimental comparison analysis, the target small arms were included most operating small arms in our country. The sound pressure levels were measured at a certain distance which was predetermined according to US army firing test procedure, TOP 3-2-045. By this experimental study, the sound pressure levels of 5.56 mm caliber small arms are 143 dB ~ 145.4 dB and 7.62 mm caliber small arms are 144 dB ~ 145.2 dB. Between the heavy machine gun K12 and M60, the sound pressure level of K12 is slightly lower than M60.Also silencer for K14 snifer rifle was tested. Using this result, it has been found that the reduction effect of the silencer is 15.4 dB but the improvements of silencer performance in the high frequency range have to be studied later on.

• Journal of Sensor Science and Technology
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• v.16 no.1
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• pp.17-23
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• 2007

This paper presents a miniaturized turn-counting sensor (TCS) where the geomagnetism and high-rpm rotation of ammunition are used to detect the turn number of ammunition for applications to small-caliber turn-counting fuzes. The TCS, composed of cores and a coil, has a robust structure with no moving part for increasing the shock survivability in the gunfire environments of ${\sim}30,000$ g's. The TCS is designed on the basis of the simulation results of an electromagnetic analysis tool, $Maxwell^{(R)}$3D. In experimental study, the static TCS test using a solenoid-coil apparatus and the dynamic TCS test (firing test) have been made. The presented TCS has shown that the induction voltage of $6.5{\;}mV_{P-P}$ is generated at the magnetic flux density of 0.05 mT and the rotational velocity of 30,000 rpm. From the measured signal, the TCS has shown the SNR of 44.0 dB, the nonlinearity of 0.59 % and the frequency-normalized sensitivity of $0.26{\pm}0.01{\;}V/T{\cdot}Hz$ in the temperature range of $-30{\sim}+43^{\circ}C$. Firing test has shown that the TCS can be used as a turn-counting sensor for small-caliber ammunition, verifying the shock survivability of TCS in high-g environments.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.4
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• pp.453-461
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• 2016

The paper represents the experimental analysis of the shock noise of medium caliber guns when a projectile is passed through the shielding material. In the study, the shielding material was constructed and tested in three separate experiments. The shielding material was not installed for medium caliber gun in Case 1. A medium caliber gun was fully covered with shielding material in Case 2, and another one was put with shielding material near muzzle in Case 3. In each experiment, the experimental data was compared with each other. Results showed the firing shielding material achieved a significant noise reduction in $90^{\circ}$ to the noise source. Case 3 is confirmed to be better effective than Case 2 in the near field. But, the noise reduction in the far field is small in quantity due to the low frequency. The paper is considered that further study is necessary for the shielding material which can absorb a low frequency noise in the future.

• Magazine of the Korea Concrete Institute
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• v.25 no.3
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• pp.43-47
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• 2013