• Journal of radiological science and technology
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• v.9 no.1
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• pp.89-92
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• 1986

Generally the inverse square law (ISL) is applied by use of intensity scale method, that is distance scale method, when we practice sensitometry of X-ray film. It was reported that the failure of the ISL had occurred in the many experiments. Thus authors obtained some conclusions of the exponent value of distance by use of dosimeter and fluorescence meter in the range of tube voltage 60 - 120 kvp, that is the range of diagnostic energy. Those conclusions were as follows its exponents were produced as 2.1383 - 2.1763 in dosimeter, as 2.1190-2.2152 in fluorescence meter. This revealed that the perfect ISL was failded and that numerical differences were shown in each measurem apparatus. Therefore it is need to study the exponent at each tube voltage for the precise supply of fixed quantity on the characteristic curve's horizontal axis.

• Korean Journal of Plant Taxonomy
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• v.41 no.4
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• pp.429-439
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• 2011

We investigated the flora of Imja-do(Isl.), an island of the Shinan archipelago, located in Imja-myeon, Shinan-gun, Jollanamo-do and discussed the vascular plants found there. Twenty-four separate field trips (100days) were completed from August of 1997 to October of 2009. As a result, we identified the distribution of 526 taxa in Imja-do(Isl.), comprising 112 families, 331 genera, 463 species, 1 subspecies, 60 varieties, and 2 forms. There are a total of 78 taxa of floristic regional indicator plants and one taxon of level II endangered species, Millettia japonica, as designated by the Korean Ministry of the Environment. The floristic regional indicator plants are as follows; four taxa of level V such as Utricularia bifida, two taxa of level IV such as Cladium chinense, 14 taxa of level III such as Aletris spicata, three taxa of level II, and 55 taxa of level I. In addition, one endangered species (EN), Nymphoides coreana, five vulnerable species (VU),such as Ilex cornuta, and three near-threatened species (NT) such as Utricula riaracemosa, were found in the investigated area. The plants of Imja-do(Isl.) are classified into four types based on the plant geographical origin, as follows: 1) boreal plants advancing southward in a glacial period, 2) temperate plants spreading eastward from the Himalayas and China to Japan passing through the south coast of Korea, 3) subtropical plants, and 4) indigenously developed endemic species of the warm-temperate region of East Asia.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2002.10a
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• pp.47-47
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• 2002

• Animal Systematics, Evolution and Diversity
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• v.29 no.1
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• pp.92-95
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• 2013

Two ennomine species, Amblychia angeronaria Guen$\acute{e}$e and Peratostega deletaria (Moore), are reported for the first time from Korea. Amblychia angeronaria was collected from Isl. Gageo-do, in the south west of Korea. The species is distinguished by the large wingspan, the ochreous forewing with a row of large white dots on the postmedian and a grayish apical dot, and the grayish or dark ochreous hindwing with undulating postmedial line and dark grayish subterminal line. Peratostega deleraia was collected from Isl. Jeju-do, and can be distinguished by the dark brown forewing with a blackish dentate postmedian and a light brown apical dot, and the dark brown hindwing with the light brown subtermen and angulate termen. Diagnosis and description of the species are given along with figures of the male and female genitalia.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.3
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• pp.358-365
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• 2016

In this study, one-dimensional analysis under the assumption of an inviscid flow was conducted for the experiment initiated by the French-German Research Institute of Saint-Louis (ISL) in order to investigate the energy effect of aluminum combustion. Previous theoretical analysis based on the assumptions of isentropic compression and a constant specific heat derived by ISL claimed that the experiment was not affected by the heat of aluminum combustion. However, rigorous analysis in present investigation that considered the average properties behind the shock wave compression and temperature-dependent specific heat showed that the S225 experiment was partially affected by the aluminum combustion. The increase in heat due to aluminum combustion was estimated from the rigorous analysis.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.5-8
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• 1998

기존의 바이폴라 논리회로에서 신호변환시 베이스 영역의 소수 캐리어를 빨리 제거 하기 위해서, 베이스 부분의 매몰충을 줄여서 npn트랜지스터의 베이스와 에피충과 기판사이에 병합 pnp 트랜지스터를 생성한 트랜지스터와 게이트 당 전달 지연 시간을 측정하기 위한 링-발진기를 설계, 제작하였다. 게이트의 구조는 수직 npn 트랜지스터와 기판과 병합 pnp 트랜지스터이다. 소자 시뮬레이션의 자료를 얻기 위하여 수직 npn 트랜지스터와 병합 pnp 트랜지스터의 전류-전압 특성을 분석하여 특성 파라미터를 추출하였다. 결과로서 npn 트랜지스터의 에미터의 면적이 기존의 접합넓이에 비해서 상당히 적기 때문에 에미터에서 진성베이스로 유입되는 캐리어와 가장자리 부분으로 유입되는 캐리어가 상대적으로 많기 때문에 이 많은 양은 결국 베이스의 전류가 많이 형성되며, 또 콜렉터의 매몰층이 거의 반으로 줄었기 때문에 콜렉터 전류가 적게 형성되어 이득이 낮아진다. 병합 pnp 트랜지스터는 베이스폭이 크고 농도 분포에서 에미터의 농도와 베이스의 농도 차이가 적기 때문에 전류 이득이 낮아졌다. 게이트를 연결하여 링-발진기를 제작하여 측정한 AC특성의 출력은 정현파로 논리전압의 진폭은 200mV, 최소 전달 지연시간은 211nS이며, 게이트당 최소 전달지연 시간은 7.26nS의 개선된 속도 특성을 얻었다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.244-247
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• 2008

Based on ISL' S225 superdetonative mode ram accelerator, numerical simulation is conducted for strong mixture cases ($2H_2+O_2+3CO_2,\;2H_2+O_2+2.5CO_2$). For 3.0CO2 case, projectile is not acclerated, but 2.5CO2 case has sucessful acceleration. It shows that superdetonative mode ram accelerator can be operated when using mixture which strong enough to ignition.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1998.11a
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• pp.151-154
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• 1998

기존의 바이폴라 논리회로에서 신호변환시 베이스 영역의 소수 캐리어를 빨리 제거하기 위해서, 베이스 부분의 매몰층을 줄여서 npn트랜지스터의 베이스와 에피층과 기판사이에 병합 pnp 트랜지스터를 생성한 트랜지스터와 게이트 당 전달 지연 시간을 측정하기 위한 링-발진기를 설계, 제작하였다. 게이트의 구조는 수직 npn 트랜지스터와 기판과 병합 pnp 트랜지스터이다. 결과로서 npn 트랜지스터의 에미터의 면적이 기존의 접합넓이에 비해서 상당히 적기 때문에 에미터에서 진성베이스로 유입되는 캐리어와 가장자리 부분으로 유입되는 캐리어가 상대적으로 많기 때문에 이 많은 양은 결국 베이스의 전류가 많이 헝성되며, 또 콜렉터의 매몰층이 거의 반으로 줄었기 때문에 콜렉터 전류가 적게 형성되어 이득이 낮아진다. 병합 pnp 트랜지스터는 베이스폭이 크고 농도 분포에서 에미터의 농도와 베이스의 농도 차이가 적기 때문에 전류 이득이 낮아졌다. 게이트를 연결하여 링-발진기를 제작하여 측정한 AC특성의 출력은 정현파로 논리전압의 진폭은 200mV, 최소 전달 지연시간은 211nS이며, 게이트당 최소 전달지연 시간은 7.26nS의 개선된 속도 특성을 얻었다.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.833-836
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• 1999

In this paper, the communication performance and its characteristics of the polar Low Earth Orbit(LEO) mobile satellite have been described in terms of the generalized performance parameters via geometric modeling and analysis. Especially, the general formula related to the parameters such as the number of orbits(M) and the number of satellites per orbit(N) were derived in the LEO satellite system for voice service, and then we applied the general result to IRIDIUM system(M＝6, N＝11) that would be scheduled to commercialize soon. The offered traffic of Inter Satellite Link(ISL), ISL link blocking probability as well as both new call blocking probability and the probability of forced termination for the on going call are calculated as the result of performance analysis.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.21-25
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• 1999

In order to remove minority carries of the base region at changing signal in conventional bipolar logic circuit, we made transistor which is composed of NPN transistor shortened buried layer under the Base region, PNP transistor which is merged in base, epi layer and substrate. Also the Ring-Oscillator for measuring transmission time-delay per gate was designed as well. In the result, we get amplitude of logic voltage of 200mV, the minimum of transmission delay-time of 211nS, and the minimum of transmission delay-time per gate of 7.26ns in AC characteristic output of Ring-Oscillator connected Gate.