• 한국군사과학기술학회지
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• 제8권2호
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• pp.58-66
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• 2005

This paper presents miniaturized setback generators based on the conversion of mechanical energy into electrical energy for military applications, especially power supply for electronic fuzes. In order to minimize the volume of setback generators, a ring-shaped magnet enclosing a coil assembly is adopted. A mechanical safety system, shear plate, is used as a release mechanism of the setback generators to prevent the generators from operating accidentally. The setback generators are intended not to ignite an electrical detonator but to charge a capacitor which is capable of driving electronic circuit of fuze. We design the setback generators using the simulation results of an electromagnetic analysis tool, $Maxwell^{(R)}$ 2D. In experimental study, we perform safety tests of the shear plate and firing tests of the fabricated setback generators. The present setback generators show that the voltage of 14.2V is charged at the capacitor of $30{\mu}F$ within the charging time of 0.68msec and the critical acceleration for safety is 5,000G, thus verifying that the setback generators with a ring-shaped permanent magnet can be applicable to the power supply of small-caliber electronic fuze.

• Journal of Cerebrovascular and Endovascular Neurosurgery
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• 제20권4호
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• pp.235-240
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• 2018

The safety and feasibility of simple coil embolization and stent deployment for the treatment of posterior inferior cerebellar artery (PICA) aneurysms, as well as their radiologic and clinical results, have not been adequately understood. Especially, if dissecting aneurysm of proximal PICA is associated with small caliber PICA and stenosis of ipsilateral vertebral artery orifice (VAO), endovascular coiling with saving of PICA is not always easy. This 64-year-old man presented with subarachnoid hemorrhage due to a ruptured dissecting aneurysm of left proximal PICA. The aneurysm was irregularly fusiform in nature with a shallow PICA orifice (1.4 mm) and narrow caliber (0.9-1.5 mm). Moreover, the ipsilateral VAO showed severe stenosis (1.8 mm). We performed bifemoral puncture and chose additional route from right vertebral artery to left vertebrobasilar junction for retrograde approach and deployment of LVIS Jr. intraluminal support at proximal PICA. And then, the antegrade approach and coiling of aneurysm was done. Despite of transient thrombus of PICA, the aneurysm was successfully secured with preservation of whole PICA course. For preservation of narrow PICA with ipsilateral VAO stenosis, the contralateral approach and deployment of LVIS Jr. intraluminal support may be considered.

• 한국국방경영분석학회지
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• 제23권1호
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• pp.25-46
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• 1997

In this paper, we consider a tow-person zero-sum game in which an attack helicopter with a missile wishes to destroy a tank. The tank has much small-caliber ammunition for protection itself from the attack helicopter. And the attack helicopter possesses a missile for attacking the tank. We develop models for the behavior of the attack helicopter, in terms of missile launch time, and of the tank, in terms of ammunition firing rate, in several situations. In particular, we examine the Weiss-Gillman model.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 가을학술발표대회논문집
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• pp.145-146
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• 2023

One of the causes of recent construction site collapses was that the compressive strength of concrete was less than half of the allowable design standard strength range. In the safety diagnosis of structures, the compressive strength of concrete is a factor that determines the durability of a building. Therefore, in this study, we aim to examine the characteristics of compressive strength according to the particle size distribution of coarse aggregate among the compressive strength factors using small-diameter cores. To avoid problems when collecting cores, core specimens with diameters of 100×200, 50×100, and 25×50 (mm) were manufactured directly. As a result of measuring the compressive strength of concrete for each diameter, the larger the core diameter, the higher the compressive strength. has increased.

• 한국군사과학기술학회지
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• 제12권2호
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• pp.146-151
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• 2009

It is known that muzzle flash can be generated by the reaction between the oxygen in the air and unburned gunpowder contained in the propellant gas if a barrel is not long enough to burn gunpowder fully inside of the barrel. A hugh muzzle flash, which is a characteristic of small arms with short barrel length, disturbs a shooter in aiming at the target at night by making the shooter blind for a while and endangers the shooter's life by revealing firing position to enemies. In addition, the heat of muzzle flash can deteriorate the performance of thermal sights, which are attached to small arms for effective night combat. In this paper, flash suppressors of different shapes were designed for a newly developed 5.56mm caliber rifle with short barrel length and the performance of each flash suppressor to reduce the muzzle flash was compared by on-site test firing. Through the test firing, a highly efficient design of flash suppressor for reducing the muzzle flash was identified. The result of the paper can be referred when designing flash suppressors for small arms with short barrel length.

• 한국산업정보학회논문지
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• 제14권4호
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• pp.116-127
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• 2009

본 연구는 스틸 파이프 생산의 과거 이력을 분석하여 주요 특성별 높은 수율을 갖는 제품을 선별하고 각 공정별 최소 불량률을 가진 제품 모델을 구현함으로써 제품 생산의 효율성을 제고하기 위한 목적으로 수행되었다. 이를 위해 본 논문에서는 주문을 통해 생산되는 각종 스틸 파이프 제품들의 특성을 비교 및 분석하여 어떠한 특성을 가지는 제품들이 가장 높은 수율을 창출해내고 적은 불량을 발생시키는지 의사결정트리 데이터마이닝 기법을 적용하여 분석하였다. 실험 결과로부터 중소구경이 많은 ERW 스틸 파이프는 기호에 의해, 그 외 주로 대구경 범위인 롤벤더, 스파이럴 스틸 파이프 경우에는 외경 범위에 따라 수율과 불량률이 분류되고 있다는 사실을 확인하였다. 본 연구는 주요 특성별 수율과 불량률이 어떠한 형태를 나타내는지 수치적으로 분류 및 구체화하여 그 영향정도를 구분하였다.

• 한국건축시공학회지
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• 제20권1호
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• pp.43-51
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• 2020

소부대 방호시설의 주된 목적은 적의 모든 무기체계에 대한 완벽한 방호가 아니며, 한국군의 경우, 지근탄에 대한 방호를 적용하고 있다. 특히 소구경 탄자의 경우, KM 80탄을 기준으로 설정하고 있는데, 이에 대한 경험적 설계방법과 구조공학적 설계방법 모두 현실을 제대로 반영하지 못한다는 선행연구들이 있다. 이에 실사격 실험을 수행한 선행연구에서는 콘크리트 슬래브의 소구경 탄자에 대한 관입저항력 계산식을 제안한 바 있다. 그러나, 해당 실험에서는 콘크리트 강도만을 변수로 설정하였고 콘크리트의의 두께, 굵은골재의 종류, 탄자의 편주각, 고강도 콘크리트 등에 대한 변수가 고려되지 않았다. 따라서 본 연구에서는 콘크리트의 두께와 자철광의 함량에 따른 방탄성능을 평가하였다. 그 결과 탄자의 편주각에 의한 오차를 연발사격에 의해 상쇄시킬 수 있다는 것과 자철광의 함량과 콘크리트 두께는 방호성능 향상에 영향을 주지 않는다는 것을 통계적으로 확인하였다.

• 대한기계학회논문집A
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• 제31권7호
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• pp.764-776
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• 2007

On the human-rifle system, the human body is affected by the firing impact. The firing impact will reduce the firing accuracy and change the initial shooting posture. Therefore the study of biomechanical characteristics using human-rifle modeling and numerical investigation is needed. The musculoskeletal model is developed by finite element method using beam and spar elements. In this study structural analysis has been performed in order to investigate the human body impact by firing of 5.56mm small caliber machine gun. The firing experiments with the standing shooting postures were performed to verify analytical results. The result if this study shows analytical displacements of the human-rifle system and experimental displacements of the real firing. As the results, the analytical displacement and stress of human body are presented.

• 대한의용생체공학회:의공학회지
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• 제17권3호
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• pp.355-364
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• 1996

Construction of the stable monolayer of endothelial cells onto physicochemically modified polymeric surFace is one of the appropriate method to develop the small caliber vascular graft with the long-term patency. In this study, we constructed the monolayer of endothelial cells on the fibronectin rind the extracellular matrix-coated polyurethane surface derived from human fibroblast cells. To elucidate the adhesion strength of endothelial cells on the extracellular matrix-coated polyurethane, a laminar flow chamber apparatus was developed to exposure the shear stress on the apical membrane of ondothelial cells. Endothelial cells show the strongest adhesion after two days of seeding onto the fibronectin-coated polyurethane surface, whereas endothelial cells on the extracellular matrix derived from the human flbroblast cells show the minimal doubling time of cellular growth.

• 한국군사과학기술학회지
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• 제19권2호
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• pp.177-184
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• 2016

This paper presents a strike velocity estimation using the recursive Bayesian filter that operates both correction and prediction models to probabilistically remove noises of sensors and accurately estimate the strike velocity during the real-time experiments. Four different types of bullets such as 5.56 mm M193, 7.62 mm M80, 5.45 mm 7N10 and 7.62 mm MSC were used to validate the proposed method. Compared to the existing method, the proposed method statistically results in higher stability of the strike velocity estimation as well as its reliability for the ballistic limit velocity computation.