• Defense and Technology
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• no.10 s.164
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• pp.45-47
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• 1992

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.735-738
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• 2011

본 논문에서는 LS-DYNA를 이용하여 원자력 운반용기의 탄자충격에 대한 해석을 수행하였다. 문명의 발달과 더불어 원자력 발전소는 많이 생겼으며 미래에도 유망하다. 원자력 발전소에서 발생되는 사용 후 핵연료에는 환경이나 사람들에게 유해한 방사성 물질이 포함되어 있기 때문에 이를 운반하는 운반용기에 대한 구조적 안전성 확보가 필요하다. 운반용기의 이동과정에서 여러 가지 사고가 날 수 있으므로 이에 대한 대비가 필요하다. 해석에는 운반플라스크와 컨테이너가 사용되었다. 운반플라스크 안에 컨테이너가 들어가 있는 형상을 갖는데 이 부분에 탄자 충격을 가하고, 이 때 운반용기에서 받는 충격량과 변화에 대해 관찰하였다. 탄자도 실제 상황과 비슷하게 하기 위해 보편적으로 사용되는 k-2 소총에 들어가는 것으로 사용하였다. 이를 통하여 운반용기에 탄자충격이 가해졌을 때 구조적 안전성을 평가하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.163-166
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• 2009

Bullet and fragment impact test with rocket motors was performed and characteristics of the results were analyzed. The material of the motor case was carbon epoxy composite. The motor was loaded with HTPE propellants to improve the insensitive munitions characteristics. In the tests, sound pressure and heat flux sensors were used to determine the category of response according to the standard. The reaction response of all of the HTPE motors impacted by bullet and fragment was judged as Type V burning.

• The Journal of Aerospace Industry
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• s.47
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• pp.23-39
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• 1998

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.3
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• pp.345-352
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• 2011

This paper focuses on the properties analysis of 9mm bullet dual structure core to substitute current lead core by environment-friendly combination of W-Cu-Ni system high density composite materials. So the four combination samples were made of dual core with the different center of gravity location backward or forward compare to that of lead type bullet, and we experimented about the performance of 9mm bullet dual structure core. In the experimental results, the outer shape of core of four environment friendly samples on the target maintain marginally, while the current lead core bullets are completely crushed after hitting the target. The penetration depth of environment friendly samples excel seven times to lead type bullet and the three out of four samples with forward adjusted center of gravity penetrate deep as twice as ones backward. The impact tolerance of all four samples satisfies military specification, however, more firing tests are required to improve reliability of scattering distribution.

• Composites Research
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• v.22 no.3
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• pp.66-73
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• 2009

Total thickness, areal density and mass moment of inertia of materials are important material factors for structural characteristics. In this work, a material-structural optimization was performed up to the maximum ballistic limit of multi-layered composite structures under high impact velocity followed by the investigation of the influence of these factors on an impact absorption performance. A unified model combined with Florence's and Awerbuch-Bonder's models was used in optimizing the multi-layered composite structure consisting of CMC, rubber, aluminum and Al-foam. Total thickness, areal density and mass moment of inertia were used for the optimization constraint. As shown in the results, the ballistic limit determined from a newly developed unified model was closely similar to the finite clement analysis. Additionally, the ballistic limit and impact absorption energy obtained by the optimized structure were improved approximately 16.8% and 26.7%, respectively comparing with a not optimized multi-layered structure.

• Journal of International Area Studies (JIAS)
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• v.12 no.4
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• pp.395-420
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• 2009

Academic discourses on Swahili identity have been focused on either its Bantu or Arabic-originated theories. Both theories, nevertheless, have a common feature: a unilineal origin of Swahili identity. This paper questions on this Swahili identity and argues that Swahili identity has been developed through historical experience and discourses. For this, the paper utilizes Barth's theory of situationalism. Barth(1998(1969)) suggests that maintaining an ethnic identity is a personal or group choice out of multiple layers of social identities according to his or their social environments. Tanzanian Swahili identity is a good case for this analysis. Based on fieldwork conducted at Magomeni and Msasani in Dar es Salaam, a capital of Tanzania, the paper shows that residents in both areas hold strong Swahili identities although they have different social and historical experience. In case of Magomeni, most of the residents came from Zanzibar, a core Swahili cultural area. They trace their original genealogy from Arabia peninsular. Besides, they argue that they speak a proper kiSwahili(Swahili language) distinguishable from inland kiSwahili. On the contrary, residents of Msasani show variety of ethnic identities, far from a proper Swahili. They have adapted Swahili identities since the independence of Tanzania. With the help of strong socialist policies, including a language policy, most of Tanzanian ethnic groups have ignored their own identities and accommodated a national identity, Tanzanian(waTanzania) or Swahili people(waSwahili). Makonde immigrants from Mozambique who consists the majority of residents in Msasani also easily accommodate Swahili identity in the course. Therefore, Makonde have began to rebirth as waSwahili by claiming that they are living in Tanzania and speak kiSwahili as a mother tongue.

• Journal of the KSME
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• v.50 no.4
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• pp.42-45
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• 2010

초속 수 킬로미터에 달하는 탄자 충돌 해석과 같은 고속 충돌 문제는 매우 짧은 작용시간, 지배적인 과도 응답 상태, 관성효과의 중요성 등을 특징으로 들 수 있다. 이 글에서는 고속 충돌 해석을 위한 삼각형/사면체 요소를 적용한 operator-splitting 유한 요소 해석 기술에 대해 소개하였다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.3
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• pp.261-268
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• 1985

본 연구의 목적은 외적요인으로서 바람과 내적요인들이 탄자에 영향을 미칠때 탄의 동적특성변화를 예측하는데 있다. 즉 탄의 X.Y.Z축 자취, .alpha.각(angle of atta- ck)의 변화, .PHI.와 .theta.의 관계 그리고 사각과 바람에 의한 탄의 동적특성변화등을 해석 하는데에 있다.

• Korean Journal of Microbiology
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• v.14 no.2
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• pp.57-64
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• 1976

About 300 specimens belong to the Basidiomycetes are collected from Solbaek and Andong areas. 44 genera and 50 species including lepista subnuda, Pholiota squarrosoides and Craterellus aureus, which are unrecorded in Korea, are identified according to the Imazaki-Hongo's classification key.