• 한국표면공학회지
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• 제46권4호
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• pp.145-152
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• 2013

The growth behavior of nanocrystalline diamond (NCD) film has been studied for three different substrates, i.e. bare Si wafer, 1 ${\mu}m$ thick W and Ti films deposited on Si wafer by DC sputter. The surface roughness values of the substrates measured by AFM were Si < W < Ti. After ultrasonic seeding treatment using nanometer sized diamond powder, surface roughness remained as Si < W < Ti. The contact angles of the substrates were Si ($56^{\circ}$) > W ($31^{\circ}$) > Ti ($0^{\circ}$). During deposition in the microwave plasma CVD system, NCD particles were formed and evolved to film. For the first 0.5h, the values of NCD particle density were measured as Si < W < Ti. Since the energy barrier for heterogeneous nucleation is proportional to the contact angle of the substrate, the initial nucleus or particle densities are believed to be Si < W < Ti. Meanwhile, the NCD growth rate up to 2 h was W > Si > Ti. In the case of W substrate, NCD particles were coalesced and evolved to the film in the short time of 0.5 h, which could be attributed to the fact that the diffusion of carbon species on W substrate was fast. The slower diffusion of carbon on Si substrate is believed to be the reason for slower film growth than on W substrate. The surface of Ti substrate was observed as a vertically aligned needle shape. The NCD particle formed on the top of a Ti needle should be coalesced with the particle on the nearby needle by carbon diffusion. In this case, the diffusion length is longer than that of Si or W substrate which shows a relatively flat surface. This results in a slow growth rate of NCD on Ti substrate. As deposition time is prolonged, NCD particles grow with carbon species attached from the plasma and coalesce with nearby particles, leaving many voids in NCD/Ti interface. The low adhesion of NCD films on Ti substrate is related to the void structure of NCD/Ti interface.

• 한국방사선학회논문지
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• 제10권4호
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• pp.247-253
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• 2016

초음파 장비는 여러 질환을 진단하는 장비로서 널리 사용되고 있으나, 초음파영상 품질의 평가방법에서는 정량적 표준이 없는 실정이다. 따라서 본 연구에서는 ATS-539 다목적 팬텀 내 8 mm 표적의 파라미터로서 주파수, Dynamic range, 초점수를 변화하여 예민도의 SNR과 영상의 히스토그램을 분석하고 왜곡도를 측정하여 표적별 적합한 주파수 및 파라미터를 도출하여 초음파영상의 병변 진단율을 향상 하고자 한다. 실험재료는 초음파 장비, ATS-539 다목적 팬텀을 사용하며, 실험방법은 영상 평가 팬텀의 8 mm를 주파수(2, 3, 4 MHz, 하모닉 3, 4, 4.5 MHz), Dynamic range(58, 68, 78, 88, 98), Focus(2, 4, 6개)를 변화시키면서 85장의 영상을 획득한다. 8 mm 영상의 예민도를 Image J 프로그램에서 각 표적별 SNR을 측정하고, 왜곡도는 신호의 히스토그램에서 백그라운드 값을 뺄셈하여 측정한다. 측정 결과 값에서 상위 40% 결과에서 파라미터 변화에 따라 예민도의 SNR, 왜곡도의 변화양상의 데이터 값을 산출하여 초음파 장비에서 적절한 영상의 품질을 나타내는 파라미터를 도출하였다. 결과는 초점수가 증가하면 SNR이 높고 왜곡도가 감소하며, 주파수 4 MHz에서 SNR값이 높고 왜곡도가 감소하였다. 그리고 Dynamic range 88, 98에서 최적의 영상을 나타내었으며, 실험 결과값을 기초로 초음파영상의 품질을 평가한다면 보다 정확한 초음파 진단이 가능할 것으로 사료된다.

• 한국의류학회지
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• 제34권2호
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• pp.303-317
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• 2010

This study helps in the production of brassieres suitable for female adults by researching the actual wearing conditions and purchasing status, satisfaction rate, and preferences of female college students in their early 20's. The collected data was analyzed by a SPSSWIN 13.0 Program and the results of the research are as follows. 1. There is a noticeable difference between the breast satisfaction rate and breast size, in addition the satisfactory rate was higher in the normal breast size or a little ample size than in the very small or very big size. According to the shape, the satisfactory rate for the breast appeared to be high in the case of the recognition and evaluation of the hemisphere type than the flat, cone, pop out, and downward type. 2. For fitness, the looseness at the top of the cup (pressed between the breasts at the upper part of the front middle), pressing and looseness at the upper sides of the cup, inappropriate size of the cup, tightness of the wings, tightness at the bottom round of the breasts, the narrow width of the wire, wide space of the shoulder strings, and the sliding of the shoulder strings had problems that needed improvement. 3. The major priorities for purchasing brassieres are size, fitness, and aesthetic qualities. As a result, the size and the fitness are more important than the trend or decorations since the brassiere has the function to support the breasts that shows that hygiene and sanitation are recognized as an important standard for undergarment selection. The size and the fitness are important factors regardless of breast types in the examination of the selection standards of the brassieres for each breast type, but the cone and hemisphere types have higher preferences for design; the pop out type has more considerations for the material of the cloth. The result show that appearance is more important for smaller breasts, but the functionality of the brassier is more important than the appearance for medium and larger breast sizes.

• Restorative Dentistry and Endodontics
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• 제14권2호
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• pp.38-48
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• 1989

이 연구의 목적은 연화 gutta-percha 주입 근관충전법에서 효과적인 근관폐쇄를 얻기위해 함께 사용하는 sealer의 척절한 조도률 측정하는데 있다. 실험에 사용된 sealer는 $0.5m{\ell}$의 유지놀에 산화아연 분말을 혼화하여 얻은 $0.5m{\ell}$의 혼합물이 두 유리판 사이에서 120gm의 무게에 의하여 퍼지는 정도로써 측정한 조도에 상응하는 분말액비(比) 대로 산화아연 분말과 유지놀을 혼합하여 조도 65.45mm, 46.80mm, 28.95mm 및 22.60mm의 sealer를 제조하였다. 발거된 125개의 하악 대구치에서 원심근을 절취하여 step-back 방법으로 근관형성, 제조된 sealer를 근관벽에 피복하고 $70^{\circ}C$에서 연화된 gutta-percha를 주입, 근관충전하였다. 실험치근은 2% methylene-blue 색소용액에 침적시켜 $37^{\circ}C$의 항온기에서 48시간 경과시킨후 근단공을 통한 색소침투의 정도를 측정하여 다읍의 결과를 얻었다. 연화 gutta-percha 주입 근관충전법에서 sealer를 사용하지 않은 군이 sealer를 사용한 군보다 색소침투는 더 크게 나타났다(p<0.05). 일정한 조도의 범위 65.45mm~22.60mm에서 조도 65.45mm의 sealer는 조도 28.9mm 및 22.60mm보다 폐쇄효과는 더 높게 나타났고(p<0.05) 조도 46.80mm의 sealer 보다도 더 높게 나타났으나 통계학적 유의성은 없었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 춘계학술회의 초록집
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• pp.16-16
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• 2010

GaN-based light-emitting diodes (LEDs) are attracting great interest as candidates for next-generation solid-state lighting, because of their long lifetime, small size, high efficacy, and low energy consumption. However, for general illumination applications, the external quantum efficiency of LEDs, determined by the internal quantum efficiency (IQE) and the light extraction efficiency, must be further increased. The IQE is determined by crystal quality and epitaxial layer structure and high value of IQE more than 70% for blue LEDs have been already reported. However, there is much room for improvement of light extraction efficiency because most of the generated photons from active layer remain inside LEDs by total internal reflection at the interface of semiconductor with air due to the high refractive index difference between LEDs epilayer (for GaN, n=2.5) and air (n=1). The light confining in LEDs will be reabsorbed by the metal electrode or active layer, reducing the efficacy of LEDs. Here, we present the first demonstration of enhanced light extraction by forming a MgO nano-pyramids structure on the surface of vertical-LEDs. The MgO nano-pyramids structure was successfully fabricated at room temperature using conventional electron-beam evaporation without any additional process. The nano-sized pyramids of MgO are formed on the surface during growth due to anisotropic characteristics between (111) and (200) plane of MgO. The ZnO layer with quarter-wavelength in thickness is inserted between GaN and MgO layers to increase the critical angle for total internal reflection, because the refractive index of ZnO (n=1.94) could be matched between GaN (n=2.5) and MgO (n=1.73). The MgO nano-pyramids structure and ZnO refractive-index modulation layer enhanced the light extraction efficiency ofV-LEDs with by 49%, comparing with the V-LEDs with a flat n-GaN surface. The angular-dependent emission intensity shows the enhanced light extraction through the side walls of V-LEDs as well as through the top surface of the n-GaN, because of the increase in critical angle for total internal reflection as well as light scattering at the MgO nano-pyramids surface.

• IUGG한국위원회:학술대회논문집
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• IUGG한국위원회 2003년도 정기총회 및 학술발표회
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• pp.15-15
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• 2003

The first crustal refraction survey in the Korean Peninsula was carried out over the survey line connecting Seosan-Yeongdong-Kyeongiu on Dec. 15, 2002. The total length of the survey line was about 300 Km and 198 portable seismometers were deployed with approximately 1.5-km interval. The survey line itself was geologically important since it was almost normal to the so-called Sino-Korean structural trend. Two shots, one at Seosan (west end point) and the other at Yeongdong (mid-point), were exploded. They were 100-m deep drill well explosions. The Seosan shot consisted of a ton emulsion type explosive, while Youngdong consisted of 500 kg one. Both shots generated signals with good S/N ratios to the farthest receivers. Seismic signals were recorded by 195 receivers out of 198 ones. Although the originally planned Kyeongju shot (east end point) could not be exploded due to public discontent, the experiment was evaluated very successful. First breaks in all recorded traces were picked up and two preliminary analyses were carried out. The one is conventional flat layer analysis and the other was refraction tomographic analysis. The one resulted in average 32-km thick two-layer crust and the underlying mantle with 8.05-km/s P-velocity. The top crust layer with 3.86 kw/s P-velocity was 2.5-km thick and the lower crust layer with 6.0l km/s P-velocity was 29.5-km thick. The other resulted in a velocity cross-section. The confidence level of the velocity cross-section could not be evaluated at this time because only two shot were exploded. Detailed analyses such as surface wave dispersion are on going. Continuing crustal scale refraction surveys are planned in Korea.

• 천문학논총
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• 제30권2호
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• pp.559-563
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• 2015

Monitor of All-sky X-ray Image (MAXI) is a Japanese X-ray all-sky surveyer mounted on the International Space Station (ISS). It has been scanning the whole sky since 2009 during every 92-minute ISS rotation. X-ray transients are quickly found by the real-time nova-search program. As a result, MAXI has issued 133 Astronomer's Telegrams and 44 Gamma-ray burst Coordinated Networks so far. MAXI has discovered six new black holes (BH) in 4.5 years. Long-term behaviors of the MAXI BHs can be classified into two types by their outbursts; a fast-rise exponential-decay type and a fast-rise flat-top one. The slit camera is suitable for accumulating data over a long time. MAXI issued a 37-month catalog containing 500 sources above a ~0.6 mCrab detection limit at 4-10 keV in the region ${\mid}{b}{\mid}$ > $10^{\circ}$. The SSC instrument utilizing an X-ray CCD has detected diffuse soft X-rays extending over a large solid angle, such as the Cygnus super bubble. MAXI/SSC has also detcted a Ne emission line from the rapid soft X-ray nova MAXI J0158-744. The overall shapes of outbursts in Be X-ray binaries (BeXRB) are precisely observed with MAXI/GSC. BeXRB have two kinds of outbursts, a normal outburst and a giant one. The peak dates of the subsequent giant outbursts of A0535+26 repeated with a different period than the orbital one. The Be stellar disk is considered to either have a precession motion or a distorted shape. The long-term behaviors of low-mass X-ray binaries (LMXB) containing weakly magnetized neutron stars are investigated. Transient LMXBs (Aql X-1 and 4U 1608-52) repeated outbursts every 200-1000 days, which is understood by the limit-cycle of hydrogen ionization states in the outer accretion disk. A third state (very dim state) in Aql X-1 and 4U 1608-52 was interpreted as the propeller effect in the unified picture of LMXB. Cir X-1 is a peculiar source in the sense that its long-term behavior is not like typical LMXBs. The luminosity sometimes decreases suddenly at periastron. It might be explained by the stripping of the outer accretion disk by a clumpy stellar wind. MAXI observed 64 large flares from 22 active stars (RS CVns, dMe stars, Argol types, young stellar objects) over 4 years. The total energies are $10^{34}-10^{36}$ erg $s^{-1}$. Since MAXI can measure the spectrum (temperature and emission measure), we can estimate the size of the plasma and the magnetic fields. The size sometimes exceeds the size of the star. The magnetic field is in the range of 10-100 gauss, which is a typical value for solar flares.

• 한국수산과학회지
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• 제31권1호
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• pp.114-120
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• 1998

밀어 어미를 경상남도 김해군 상동면 매리에 위치한 하천에서 끌망과 쪽대을 사용하여 채집하여 사육하여 1995년 2월부터 5월까지 6차례에 걸쳐 산란행동과 난발생 과정을 관찰하였으며, 부화한 자어를 사육하면서 성장에 따른 형태발달을 관찰하였다. 1. 산란된 알은 수조내의 작은 돌 아랫면에 거의 원형에 가깝게 한층으로 조밀하게 매달려 있었으며, 방정후 수컷은 알을 보호하였다. 2. 수정난은 난경이 $1.28\~$1.56\times0.62\~0.67mm$로 부착사를 지닌 투명한 침성란으로 많은 소유구를 가지고 있었다. 3. 부화에 소요된 시간은 사육수온 $16.0\~18.0^{\circ}C$ (평균 $17.0^{\circ}C$)에서 수정후 146시간 30분부터 부화하기 시작하였다. 4. 밀어의 알은 발생 후반에 배체의 머리 부분이 난황의 선단부를 향하는 정상난과 반대로 난막의 기부, 즉 부착사 쪽을 향하는 역자난이 출현하였다. 5. 부화직후의 자어는 전장 $3.10\~3.30mm$ (평균 3.22 mm)로 입과 항문이 열려있지 않았고, 흑색소포는 부레위, 항문 주변, 꼬리 중앙부분의 배쪽에 산재되어 있었으며, 근절수는 $25\~27$개 였다. 6. 부화후 $3\~4$일째의 자어는 전장 $3.30\~3.85mm$(평균 3.60mm)로 난황과 유구가 거의 흡수되어 입과 항문이 열리고, rotifer를 먹기 시작하였으며, 후기자어기로 이행하였다. 7 부화후 $20\~22$일째 개체는 평균 전장 5.85mm로 성장하였으며, 척소미단이 $45^{\circ}$ 정도로 위로 굽어져 있었다.

• 헤리티지:역사와 과학
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• 제35권
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• pp.28-56
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• 2002

There is no definite theory, which archeologists have believed to be built either for the protection or ceremonial purpose, of enclosure historical site exhibited from Bronze Age to Samhan era in Korea. The main conditions of choosing right enclosure were natural levee-backswamp-plateau, which all found in village on a hill. For this reasons Kimhae Daesoeng-dong enclosure discovered in 2001 is not an exception, and therefore this enclosure has been believed to be a beginning point of the farming society. In Korea there have been 2 types of enclosure. One is that enclosure entirely surrounds whole historic site itself and the other is that enclosure partially does. Although Kimhae Daesoeng-dong historic site has been discovered only part of it, it's not believed to have the first type-which surrounds the whole enclosure historic site In this research, 3 developing steps of enclosure historic site were defined. Enclosure surrounds only a part of the historic site is 1st step. Enclosure surrounds all around the site is 2nd step. The site discovered with big round clay pottery and developed into multiple enclosure is 3rd step. Since some researches have not been accomplished, the hypothesis above was suggested to have a better understanding of the development of enclosure historic site. The purpose of enclosure has been separately explained for the protection or for the ceremony. It is difficult to assert that excavation sites could be applied to only one of two purposes. But it is possible that both purposes of enclosure such as protection and as division from ceremonial area could be applied together. Kimhae Daesoeng-dong enclosure was shown for the purpose of division from ceremonial area. But we can not ignore that since Kimhae Daesoeng-dong enclosure exposed to the Sea and dwelling area was not shown from village hill, it would be probably for the protection. However enclosure of Gujibong village area in Daesoeng-dong had used for ceremonial purpose since the Bronze Age, even this enclosure would be possible to play an important role of being a center of legend of Gaya foundation. Many unsolved questions are still lying ahead. The enclosure was used for a short time, even if dwelling area was found in and out of enclosure, there were no differences between them, and although duplicate and triplicate enclosure were found, we could not sure which were before and after. Also we could not confirm the type of enclosure with location condition which was the flat land or the top of hill on floodplain. We should not divide the types of enclosure historic site due to differences from cross section of stratum. And I expect that we will have much data such as distribution of enclosure historic site in Yeongnam area where is concerned with origin and diffusion of Japan and China.

• 한국해양학회지:바다
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• 제24권1호
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• pp.18-29
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• 2019

독도와 심흥택 해산의 정상부 및 사면에서 HD 급 비디오카메라, 2기의 LED 조명, 1개의 다목적 로봇팔, 8개의 추진기가 장착된 소형 ROV로 해저면 조사를 수행하였다. 조사에 사용된 장비는 스웨덴에서 제작된 500 m급 소형 무인잠수정 "V8 SII"과 지원모선인 "코쌀 5호"였으며, 수심 범위가 45~370 m인 조사해역의 4정점에서 총 6회 잠수를 수행하였고, 잠수시간은 운용조건에 따라 약 30~120분 소요되었다. 조사 결과, 독도 주변 해저 경사면과 해산 정상부 부근에는 다양한 크기의 암석 및 밀도 높은 부착생물인 심해성 말미잘(Actinostolidae sp.), 거미불가사리류(Ophiuridae sp.), 대게류의 서식이 확인되었다. 본 조사를 통해 얻어진 결과는 1) 주요 수산자원인 대게류의 서식 확인 및 심해생물상 자료, 2) 해저면의 퇴적상 및 지형 특성 확인, 3) 육상기원 어구 폐기물 확인 등이다. 본 탐사는 수산자원 및 생태학적으로 중요한 독도 해저면과 주변 해산의 수중환경의 첫 기록으로서, 동해의 해산 정상부의 심해 저서환경 및 생물의 직접관찰에 소형 ROV가 활용 가능함을 시사하였다.