• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.218-218
• /
• 2016

실린더 형태의 유전체 관에 나선형으로 도전체 안테나를 설치하는 타입의 유도 결합 플라즈마원은 간단한 구조로 화학 조성 분석용부터 나노 분말 제조, 반도체용 식각/증착, 표면 처리, 자동차 및 일반 산업 부품용 증착 보조원등으로 널리 사용되고 있다. 고밀도 라디칼/이온의 공급을 위해서 투입 전력을 증가시키는 경우 높은 전력 밀도로 인해서 유전체 관에 인가되는 열응력이 대기압 및 관 고정용 구조물에 의한 구조 응력에 더해져서 파손에 이르는 경우가 발생될 수 있다. 실제 실린더 길이 전체를 안테나 코일로 감는 경우에도 플라즈마 발생 밀도가 높은 지역은 중심 일부 영역에 국한 되는 공정 영역도 있어서 이에 대한 분석이 필요하다. CFD-ACE+를 이용하여 플라즈마의 생성, 냉각수의 열전도, 외부 공냉식 팬의 역할등에 대해서 수치 모델을 작성하여 검토하였다. 나선형 냉각코일의 경우 냉각수량을 일정값 이상으로 증가시키는 경우 유속이 지나치게 빨라져서 열원이 있는 내경쪽 표면에서 열전도가 유속에 비례해서 증가하지 못하는 단점이 발생할 수 있으며 냉각팬의 경우 일반적으로 장치 내부에 대해서만 모델링을 하는 데 실제로 전체 시스템의 주변에서 공기의 흐름을 넓게 해석해야 실제 냉각 효과를 파악할 수 있다. 심한 경우 냉각용 공기 흡입구와 토출구의 간격이 좁아서 열원에 의해서 가열된 공기의 상당량이 다시 냉각용 공기 흡입구로 재순환 되는 경우도 발생하기 쉽다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.6 no.1
• /
• pp.18-22
• /
• 2013

Input impedance of the inverted L antenna which is modified from a monopole antenna varies to very high input impedance value when the ratio of vertical height to horizontal length is reduced. So its impedance matching becomes very difficult. In this paper, we analyzed the input impedance variation range depending on the ratio of vertical height to horizontal length in the normal and ferrite thin film added configuration for the input impedance control. For the exact analysis involving the permittivity, permeability and conductivity of ferrite material, FDTD numerical method is used.

• Journal of Navigation and Port Research
• /
• v.28 no.6
• /
• pp.503-507
• /
• 2004

We prepared EM wave absorbers by using recycled Sr ferrite for GHz frequency, and investigated the effects of carbon additions and preparation temperatures on their EM wave absorption properties. A Sr ferrite EM wave absorber with the ratio of Sr ferrite: silicon rubber: carbon = 80 : 13.6: 6.4 wt% prepared at 7$0^{\circ}C$ showed -24 dB at 9.4 GHz and -23 dB at 5.5 GHz for 2 mm and 3 mm thickness, respectively.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2004.04a
• /
• pp.17-22
• /
• 2004

We prepared EM wave absorbers by using recycled Ba and Sr ferrites for GHz frequency, and investigated the effects of carbon additions, thickness and preparation temperatures on their EM wave absorption properties. We clarified that it is very important to consider carbon amounts in Ba and Sr ferrites and preparation temperature for Ba and Sr ferrite EM wave absorbers with high quality. In this study, the developed a EM Wave absorber satisfying over 20 dB.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.06a
• /
• pp.287-287
• /
• 2008

HTS-케이블은 구리도체 대신 고온초전도도체를 사용하여 저항이 0이 되는 초전도현상을 이용하여 대용량 전력수송이 가능한 전력케이블로서 대도시의 전력부하 집중문제를 해결할 수 있는 환경 친화적 전력케이블이다. 최근 고온초전도선재의 고임계전류밀도화 및 장척화에 힘입어 HTS-케이블의 실용화를 목표로 경제성이 있는 전력케이블을 개발하려는 움직임뿐만 아니라 실증시험 등 활발한 연구가 진행 중이다. 그러나 초전도전력케이블에서 발생되는 교류손실은 케이블의 효율을 저하시킬 뿐만 아니라 냉동기비용 증가로 인한 기존 케이블과의 가격경쟁에서 경제성을 저하시키는 주된 요인으로 작용하기 때문에 이의 상용화에 앞서 교류손실에 대한 정확한 규명이 되어야 하며 또한 실계통 투입 시 중요한 선로임피던스에 대한 정확한 규명도 필요하다. 본 논문에서는 실제 한전 주관으로 고창시험장에 설치된 배전급 22.9 kV, 100 m, 50 MVA급 3 상 HTS-케이블에 대한 통전특성을 규명하기 위하여 먼저 HTS-케이블의 DC 통전특성을 조사하였다. 또한 3상평형운전상태에서 AC 통전특성(인덕턴스 및 교류손실)을 실험적으로 조사하였으며 5m-케이블에서 측정된 결과와 비교 검토하였다.

• 한국벤처창업학회:학술대회논문집
• /
• 2018.11a
• /
• pp.261-266
• /
• 2018

우리나라 기업 창업 후 5년까지 생존율(27.5%)은 OECD 평균 생존율(43.9%)보다 낮으며 최근 5년간('11~'15년) 연평균 창업은 81만개, 폐업은 70만개로 다산다사(多産多死) 특징 보유하고 있다. 사업 실패로 인한 폐업은 개인적인 차원을 넘어 사회적인 문제로 확대되고 국가 경제에 부담으로 작용하고 있다. 이에 본 연구에서는 사업실패경험이 학습효과와 자산으로 승화하여 재창업의지에 직접적인 영향을 미치는지, 사업실패자에 대한 사회적지지가 재창업 의지에 어느 정도 상승효과를 주는지에 대해 분석하기 위해 사업실패자자들을 대상으로 자료를 수집, 실증 분석하였다. 본 연구 결과는 첫째, 사업실패경험 속성중 비재무적 손실이 발생한 경우 재창업의지에 부(-)의 영향을 미치는 것으로 나타났다. 이는 비재무적 손실이 크다면 재창업의지는 낮아지게 된다. 둘째, 재무적 손실이 발생한 경우에는 재창업의지에 영향을 미치지 못하였다. 셋째, 조절변수인 정서적지지는 비재무적 손실이 발생한 경우 재창업의지에 정(+)영향을 미치는 것으로 나타났다. 따라서 재창업지원은 이들이 경험한 비재무적 손실을 회복 할 수 있도록 정서적지지를 활용하는 다양한 정책안들이 고안 되어야 하고 사업실패로 재무적 손실이 크게 나기 전에 사업을 빠른 시일 내에 정리토록 하는 것이 재도전 시책에서 무엇보다 중요하다는 시사점을 주고 있다.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
• /
• v.8 no.8
• /
• pp.301-312
• /
• 2018

This The main objective of the study is to examine success clues of the firm influenced by top manager(Masayoshi Sohn) who belongs to Korean-Japanese third generation diaspora. A company's management style depends greatly on the value of its top manager, who also affects success and failure of the firm. SOFTBANK's management style could be influenced by the identity and values of Masayoshi Sohn. The results of the study are as follows ; firstly, his firm remains born-global firm owing to his global value rooted from his de-ethnification and studying in America. Secondly, the firm has challenge spirit owing to his experience of overcoming discrimination and repression during childhood time. and his role model 'Ryoma". Thirdly, there is a roly poly spirit in his firm because he has overcome complex coming from Korean-Japanese third generation diaspora. Finally, his company has human-oriented management philosophy because he has influenced a lot form his grand mother, Won-Cho Lee who emphasized much on human-beings. His identity and values have infiltrated Softbank's management style, which has led to the success of the company. This study will provide you with different viewpoints on the study for Korean-Japanese third generation diaspora. Especially, this study can be meaningful in which it is a study on the third generation of Korean-Japanese diaspora and the global corporations he is running since there are few such studies up to now.

• Korean Journal of Soil Science and Fertilizer
• /
• v.21 no.2
• /
• pp.135-140
• /
• 1988

A laboratory experiment was conducted to find out the number of soil microorganisms, identification and enumeration of soil microbial species on the mineral and volcanic ash soil with different cropping system of the Jeju Island. The results obtained were summarized as follows: 1. The number of bacteria was high in mineral soil with rotation of upland crops than that of volcanic ash soil with continuous cropping system. 2. According to identification of soil bacteria, the most of bacteria were composed to short rod with Gram negative. Among the bacteria species, Rhizobium spp. and Flavobacterium spp. were most high population in both of mineral and volcanic ash soil. 3. The number of fungi in mineral soils were reduced by the rotated cultivation of upland crops but no significant differences were observed in volcanic ash soil with continuous cropping system. On the other hand, Aspergillus spp., Fusarium spp., and Penicillium spp. were most high population in both of mineral and volcanic ash soil. 4. Comparing of the number and species ot microorganism to the cash crops soil in main land, about 10 to 100 times for bacteria and more than two times for the number and species of fungi were lowered in Jeju Island soil.

• Korea journal of population studies
• /
• v.30 no.3
• /
• pp.179-205
• /
• 2007

Demography has grown as an independent academic discipline in Korea during past 30 years by describing and examining changes of population components such as fertility, mortality, migration, and census, and the "Population Association of Korea" stands on the midst of the growth. High fertility of the 1960s and 70s, which was considered as a hurdle of economic growth, particularly boosted the prosper of demography in Korea by inviting a number of non-demographers as well as demographers to population-related research projects. However, as fertility gradually decreases and becomes no-threat anymore beginning the early 1990s, social interests in demography has withered to lose its academic soils in Korea. A recent phenomenon of the lowest low fertility has revived social need and interest in demography. Unfortunately, once curtailed capacity of Korean demography is not sufficient enough to provide academic and/or practical resources now. This research is conducted to cerebrate the 30th anniversary of "Population Association of Korea" and to seek ways to cultivate academic soils again and to rebuild the capacity of demography in Korea. To do this, this research examines the causes of current struggles of Korean demography by comparing its academic environments with that of America, and offers suggestions for its brighter future.

• Clean Technology
• /
• v.19 no.4
• /
• pp.410-415
• /
• 2013

The supercapacitors were fabricated using silver (Ag) nano paste and activated carbon paste on the polyimide (PI) film and 5% potassium polyacrylate (PAAK) was used for gel electrolyte. In this paper, the current collector film and the electrode film were fabricated using screen printing. The thickness of printed silver paste was $7.3{\mu}m$ and the sheet resistance has the range of $5-7m{\Omega}/square$. An activated carbon with a surface area of $1,968m^2/g$, an electronic conducting agent (SUPER P, TIMCAL) and poly (4-vinylphenol) were mixed in 2-(2-buthoxyethoxy) ethyl acetate (BCA) with a ratio of 7:1:3 to fabricate the electrode paste. To analyze electrochemical characteristics, cyclic voltammetry was performed to evaluate the stability of the devices under the voltage range of -0.5-0.5 V. The calculated specific capacitances were 44.04 and 8.62 F/g for 10 and 500 mV/s scan rates, respectively.