• 한국추진공학회지
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• 제12권6호
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• pp.12-20
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• 2008

강내탄도 전산해석 코드 개발을 위한 효율적인 방안과 수치 기법에 관해 연구하였다. 탄자이동에 의한 이동경계면에 대한 수치 해석 기법은 자유 피스톤 운동 문제를 통해서 비교 검증하였다. 강내탄도의 초기 연소를 수치적으로 계산하여 고체추진제의 연소와 기공률 효과에 의한 압력구배를 예측할 수 있었다. 본 연구를 통해서 강내탄도 전산 해석 코드 개발에 관한 방안과 기초 기법에 대한 전산화 기술을 확보하였다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1999년도 추계 학술대회논문집
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• pp.77-84
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• 1999

Numerical design optimization techniques are implemented for the improvement of the ram accelerator performance. The design object is to find the minimum ram tube length required to accelerate projectile from initial velocity $V_0$ to target velocity $V_e$. The premixture is composed of $H_2,\;O_2,\;N_2$ and the mole numbers of these species are selected as design variables. The objective function and the constraints are linearized during the optimization process and gradient-based Simplex method and SLP(Sequential Linear Programming) have been employed. With the assumption of two dimensional inviscid flow for internal flow field, the analyses of the nonequilibrium chemical reactions for 8 steps 7 species lave been performed. To determined the tube length, ram tube internal flow field is assumed to be in a quasi-steady state and the flow velocity is divided into several subregions with equal interval. Hence the thrust coefficients and accelerations for corresponding subregions are obtained and integrated for the whole velocity region. With the proposed design optimization techniques, the total ram tube length had been reduced $19\%$ within 7 design iterations. This optimization procedure can be directly applied to the multi-stage, multi-premixture ram accelerator design optimization problems.

• 한국군사과학기술학회지
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• 제14권4호
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• pp.639-647
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• 2011

In this paper, we have designed the Anti-Aircraft Artillery(AAA) model for the surface-to-air virtual engagement. The AAA model for the virtual combat simulation needs to detect the present target and estimate the target flight trajectory to find the aiming point. To find collision point of projectile fired from the artillery with the moving air target, we have presented the estimating technique for artillery aiming point. And we have analyzed the target probability of kill using Calton Hit function. Anti-air threat envelops are presented when the target velocity, position and the arrangement of four AAA are varying. Then we have compared the analyzed result using developed model with AEM model of MSA program.

• 한국추진공학회지
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• 제12권5호
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• pp.60-66
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• 2008

각종 무기체계에서 포구속도는 보다 정확한 사격제원을 산출하기 위한 자동사격통제시스템의 기초 데이터로 활용될 수 있다. 그러나 전장환경의 여러 변수들을 고려한다 해도 동일한 탄약(추진제)에서 발생하는 불규칙적인 성능특성은 정확한 포구속도 데이터를 얻는 것을 곤란하게 한다. 본 논문에서는 강내 압력을 측정하고 약실압력과 탄저압력의 실험적 관계식을 구하여 포구속도를 산출하는 방법에 대하여 연구하였다. 이러한 방법을 통해 추진제의 불규칙적인 성능특성을 보정한 포구속도를 얻음으로써 보다 정확한 데이터를 제공할 수 있으리라 생각한다.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제17권3호
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• pp.196-200
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• 2014

Co-existing pyloric submucosal masses with hypertrophic pyloric stenosis (HPS) are very rare and treating these lesions is always a problem. A 20-day-old boy presented with recurrent episodes of projectile non-bilious vomiting lasting for 5 days. HPS was suspected due to the presenting age and the symptoms. The sonography demonstrated not only circumferential wall thickening of the pylorus, but also a pyloric submucosal mass. At laparotomy, a 0.8 cm sized pyloric submucosal mass was identified along with a hypertrophied pylorus. Pyloric excision was performed due to the possibility of sustaining the symptoms and malignancy. The pathological report of the submucosal mass was ectopic pancreas. Coexisting pyloric lesions can be diagnosed along with HPS, and surgical excision, not just pyloromyotomy, should be considered in these circumstances. To the best of our knowledge, this is the first case report of pyloric ectopic pancreas and HPS to be diagnosed concurrently.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1994년도 제7회 학술발표회 및 한·일 CVD 심포지움 논문개요집
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• pp.92-92
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• 1994

Relative intensities of photons emitted from tilted carbon foils have been measured in the wavelength region 300800 nm by 0,6-2,4 MeV $H^{+}\;and\;He^{+}$ ion impacts, Ions were directed onto target surfaces at tilt angles with respect to the sllrface normal, Experimental results support the model that the observed continuum radiation is emitted from the exited carbon foil itself. At each incident projectile energy, the photon intensities of continuum spectra for tilted carbon foi Is were compatred to the stoppi ng powers of carbon for $H^{+}\;and\;He^{+}$ ions, It was found that the photon emission intensity for $H^{+}$ ion is linearly proportional to the stopping power, whereas that for $He^{+}$ ions is proportional to a higher power of the stopping power, and that this tendency increases wi th decreasing velocity of the projectiIes[1, 2].[1, 2].

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제2권1호
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• pp.99-103
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• 1999

저자들은 출생 후부터 1년에 수 회 반복되는 담즙이 포함된 사출성 구토가 있었던 9세 여아에서 발견된 십이지장 격막과 동반된 장이상회전 1례를 경험하였기에 보고하는 바이며, 장의 완전 폐쇄가 아닌 경우에는 년장아에서도 선천성 장폐쇄의 소견이 나타날 수 있으므로 구토가 심하게 반복되는 경우에는 항상 주의깊게 감별진단해야 한다.

• Advances in pediatric surgery
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• 제8권1호
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• pp.23-27
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• 2002

Infantile hypertrophic pyloric stenosis (IHPS) a common childhood disorders characterized by nonbilious projectile vomiting, an olive shaped mass in the right upper quadrant of the abdomen and visible gastric peristaltic wave in the upper abdomen. Its etiology and pathogenesis are not clear but abnormal nerve distribution of the pylorus has been $postulated^{2-6}$. We performed immunocytochemical staning to the pyloric muscle from 10 IHPS and 3 controls patients, utilizing specific monoclonal antibody to NCAM(neural cell adhesion molecule). In IHPS patients, the number of NCAM protein immunoreactive nerve fibers were less than that in normal subjects. Auerbach myenteric plexuse was well developed and interbundle nerve plexuse was present but nerve fibers supplying individual muscle cells in smooth muscle bundles were poorly developed. These results indicate reduction of innervation in smooth muscles in IHPS patients that possibly contributes to the pathogenesis of IHPS.

• Advances in Computational Design
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• 제1권2호
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• pp.139-154
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• 2016

The usage of sandwich structure is extensively increasing in lightweight protective structures due to its low density and other useful properties. Sandwich panels made of metal sheets with unfilled cellular cores are found to exhibit lower deflections by comparing to an equivalent monolithic plate of same metal and similar mass per unit density. However, the process of localized impact on solid structures involving plastic deformation, high strain rates, temperature effect, material erosion, etc. does not hold effectively as that of monolithic plate. In present work, the applications of the sandwich plate with corrugated core have been extended to develop optimized lightweight armour using foam as medium of its core by explicit finite element analysis (FEA). The mechanisms of hardened steel projectile penetration of aluminum corrugated sandwich panels filled with foams have been numerically investigated by finite element analysis (FEA). A comparative study is done for the triangular corrugated sandwich plate filled with polymeric foam and metallic foam with different densities in order to achieve the optimum penetration resistance to ballistic impact. Corrugated sandwich plates filled with metallic foams are found to be superior when compared to the polymeric one. The optimized results are then compared with that of equivalent solid and unfilled cores structure to observe the effectiveness of foam-filled corrugated sandwich plate which provides an effective resistance to ballistic response. The novel structure can be the alternative to solid aluminum plate in the applications of light weight protection system.

• 한국재료학회지
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• 제27권7호
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• pp.359-363
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• 2017

The resistance of metallic materials to ballistic penetration generally depends on a number of parameters related to projectile, impact, and armor plate. Recently, armor materials have been required to have various properties such as hardness, strength, and impact toughness in order to maintain an excellent ballistic resistance even after impact. In the present study, the influence of tempering on the microstructure and mechanical properties of an ARMOX 500T armor steel plate was investigated and then compared with those of S45C and SCM440 steels. As the tempering temperature increased, the hardness and strength gradually decreased, whereas the ductility and impact toughness clearly increased because the hardness, tensile, and impact properties were affected by the microstructural evolution and precipitation occurring during tempering. On the other hand, temper embrittlement appeared at tempering temperatures of 300 to $400^{\circ}C$ for the impact specimens tested at low temperature.