• 한국지능시스템학회논문지
• /
• 제7권5호
• /
• pp.14-20
• /
• 1997

This paper proposes a new design method for the SMC-type FLC and shows that a SMC-type LFC is an extension of the SMC with BL. The conventional SMC-type FLC uses error and change-of-error as inputs of the FLC and generates the absolute value of a switching magnitude. Then, the fuzzy rule table is constructed on a two-dimensional space of the phase plane and has commonly the skew symmetric property. In this paper, we introduce a new variable, signed distance, from the skew symmetric property of the rule table. And thd variable becomes only a fuzzy variable that is used to generate the control input of a SMC-type FLC. that is, we design a new SMC-type FLC that uses a signed distance and a control input as the variables representing the contents of the rule-antecedent and the rule-con-sequent, respectively. Then the number of total rules is reduced and the control performance is almost the same as that of the conventional SMC-type FLC. Additionally, we derive the control law of the ordinary SMC with BL from a new SMC-type FLC. Namely, we show that a FLC is an extension of the SMC with BL.

• Bulletin of the Korean Chemical Society
• /
• 제7권5호
• /
• pp.331-334
• /
• 1986

The crystal structure of thiamin tetrahydrofurfuryl disulfide, one of the ring-opened derivatives of thiamin, has been determined by the X-ray diffraction methods. The crystal is monoclinic with cell dimensions of a = 8.704 (1), b = 11.207 (2), c = 21.260 (3) ${\AA}$ and ${\beta}$ = 92.44 (2)$^{circ}$, space group P2$_{1}$/c and Z = 4. The structure was solved by direct methods and refined to R = 0.076 for 1252 observed reflections measured on a diffractometer. The molecule assumes a folded conformation in which the pyrimidine and the tetrahydrofurfuryl rings are on the same side of the ethylenic plane. The pyrimidinyl, N-formyl and ethylenic planes are mutually perpendicular to each other and the N(3)-C(4) bond retains a single bond character. The structure is stabilized by an intramolecular N(4'${\alpha})-H{\cdots}O(2{\alpha}$) hydrogen bond. The molecules are connected via N(4'${\alpha}$)-H{\cdots}(N3')$ and O(5${\gamma})-H{\cdots}(N1')$ hydrogen bonds, forming a two-dimensional hydrogen-bonding network. The tetrahydrofurfuryl ring is dynamically disordered. The overall conformation as well as the packing mode is very similar to that of thiamin propyl disulfide.

• 한국자기학회지
• /
• 제7권3호
• /
• pp.129-133
• /
• 1997

Hf 함량과 열처리 효과가 $Co_{1-x}$ H $f_{x}$(X=0.16, 0.24 ㅁㅅ.%)계 박막의 자기적 특성에 미치는 영향을 조사하기 위하여, 제작된 시료를 다양한 조건에서 열처리한 후, 강자성 공명 실험을 통해 관측된 강자성 공명 흡수선의 변화를 고찰했다. 모든 시료에 대해 다수의 volume mode 스핀파와 한 개 또는 두 개의 surface mode 스핀파가 관측되었는데, 대체적으로 이와 같은 현상은 시료 양면의 표면이방성이 0보다 작은 경우에 나타나는 특성이다. $Co_{84}$H $f_{16}$박막의 경우 열처리 온도를 225 .deg. C까지 증가시키는 동안 기판과 접촉하는 시료면의 표면 자기이방성 상수 $K_{s2}$는 -0.07 erg/$cm^{2}$에서 -0.32 erg/$cm^{2}$로 감소했으며, 공기와 접촉하는 시료면의 표면 자기 이방성 상수 $K_{s1}$은 0.18 erg/$cm^{2}$에서 -0.47 erg/$cm^{2}$로 변화하는 모습을 보였다. $Co_{76}$H $f_{24}$ 박막에서는 $K_{s2}$는 열처리 온도가 증가함에 따라 -0.31 erg/$cm^{2}$에서 -0.41 erg/$cm^{2}$로 미소하게 감소했으며, $K_{s1}$은 열처리 온도가 225 .deg. C 까지 증가하는 동안 -0.19 erg/$cm^{2}$에서 -0.60 erg/$cm^{2}$로 급격히 감소했다. 대체적으로 CoHf계 박막의 경우 공기와 접촉하는 면의 표면이방성은 열처리 온도와 Hf 함량에 매우 민감한 특성을 보이는데, 이와 같은 현상은 저온 열처리 과정(150 .deg. C ~ 175 .deg. C)에서 공기쪽 표면층에 존재하는 Hf이 산화하여 공기쪽 표면층의 Co 함량이 증가했고, 고온 열처리 과정(200 .deg. C ~ 225 .deg. C)에서 Co 원자가 확산하므로서 나타나는 현상으로 해석된다.다..다.된다.다..다.

• 한국구조물진단유지관리공학회 논문집
• /
• 제18권3호
• /
• pp.10-19
• /
• 2014

파형강판은 제형, 정현형 등의 형상으로 얇은 강판을 주름지게 가공한 것으로 두꺼운 평판을 대신하여 사용하여도 높은 면외방향의 강성을 확보할 수 있다. 또한, 아코디언효과로 축방향 강성이 거의 없어 플레이트거더의 웨브에 적용할 경우 웨브가 전단력만을 부담하는 방법으로 쉽게 설계할 수 있다. 그러나 파형강판의 전단좌굴은 평판과는 달리 국부좌굴과 전체좌굴 외에도 이들의 연성에 의해서도 좌굴이 발생하는 매우 복잡한 특성이 있으며, 이러한 연성좌굴에 대한 원인과 특성의 규명은 정현형의 경우 제형보다 연구결과가 부족한 실정이다. 따라서 본 연구에서는 정현형 파형강판의 전단좌굴 특성과 연성좌굴이 발생하는 경향에 대해서 연구하였다. 전단좌굴강도를 계산하기 위해서는 유한요소프로그램을 이용하였고 해석결과를 정해와 비교하였다. 또한, 주름의 두께와 형상 파라메타에 따른 좌굴응력 변화의 특성과 좌굴모드형상의 변화를 분석하였으며, 이들의 결과를 이론식의 결과와 비교하여 좌굴양상의 변화시점에 대해서 분석하였다.

• 한국자기학회지
• /
• 제7권1호
• /
• pp.38-43
• /
• 1997

열처리 효과가 DC 마그네트론 스파터링 방법으로 제작한 $Co_{1-x}$ $Ti_{x}$(X = 0.13, 0.16, 0.21 at.%)계 박막의 표면자기특성에 미치는 영향을 조사하기 위하여, 제작된 시료를 150 .deg. C, 175 .deg. C, 200 .deg. C, 225 .deg. C 및 250 .deg. C의 공기 분위기에서 각각 1 시간씩 열처리한 후, 강자성 공명 실험을 통해 관측된 스핀파 공명 흡수선의 거동을 고찰했다. 모든 시료에 대해 다수의 volume mode 스핀파와 한 개 또는 두 개의 surgace mode 스핀파가 관측되었는데, 대체적으로 이와같은 현상은 시료 양면의 표면이방성이 0보다 작은 경우에 나타나는 특성이다. 열처리 온도가 150 .deg. C에서 250 .deg. C로 증가함에 따라 $K_{s2}$는 -0.11 erg/c $m_{2}$에서 -0.25 erg/$cm^{2}$로 미약하게 감소했으며, $K_{s1}$은 0.16 erg/$cm^{2}$에서 -0.53 erg/$cm^{2}$로 변화하는 모습을 보였다. 이와 같은 현상은 저온 열처리 과정(150 .deg. C ~ 200 .deg. C) 에서 공기쪽 표면층에 존재하는 Ti이 산화하여 공기쪽 표면층의 Co함량이 증가했고, 고온 열처리 과정 (225 .deg. C ~ 250 .deg. C)에서 Co 원자가 확산하므로서 나타나는 현상으로 해석된다.석된다.

• 한국강구조학회 논문집
• /
• 제15권6호통권67호
• /
• pp.673-681
• /
• 2003

본 논문은 냉간성형 각형강관 T형 접합부의 최대내력에 관한 실험 연구이다. 새로운 접합부로 지관을 트러스 평면에 대해 $45{^{\circ}}$회전시켜서 주관에 용접하고 주관 웨브 측면에는 플레이트로 보강한 형상을 연구 대상으로 설정하였다. $16.7{\leq}2{\gamma}(B/T){\leq}33.3$이고 $0.63{\leq}{\beta}(b1/B){\leq}0.7$ 범위의 지관 $45{^{\circ}}$회전시킨 T형 접합부에 대하여, 기존 최대내력식과의 비교 검토를 통하여 웨브 측면 보강에 따른 내력증대 및 파괴모드의 변화 등에 대하여 실험을 통해 조사하고자 한다. 실험결과, 보강판 두께 증가에 따라 보강 실험체의 접합부 내력이 상승하는 것으로 나타났다. $2{\gamma}=33.3$이고 플레이트로 웨브 보강한 실험체는는 접합부 파괴모드가 플랜지 파괴(M2)에서 복합파괴(M3) 형태로 전환되었으며, $2{\gamma}=16.7$이고 플레이트로 웨브 보강한 실험체에서는 웨브파괴(M1)에서 플랜지파괴(M2)로 지배 파괴모드가 변화하는 것으로 나타났다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
• /
• pp.334-334
• /
• 2013

In the past decade, the infrared detectors based on intersubband transition in quantum dots (QDs) have attracted much attention due to lower dark currents and increased lifetimes, which are in turn due a three-dimensional confinement and a reduction of scattering, respectively. In parallel, focal plane array development for infrared imaging has proceeded from the first to third generations (linear arrays, 2D arrays for staring systems, and large format with enhanced capabilities, respectively). For a step further towards the next generation of FPAs, it is envisioned that a two-dimensional metal hole array (2D-MHA) structures will improve the FPA structure by enhancing the coupling to photodetectors via local field engineering, and will enable wavelength filtering. In regard to the improved performance at certain wavelengths, it is worth pointing out the structural difference between previous 2D-MHA integrated front-illuminated single pixel devices and back-illuminated devices. Apart from the pixel linear dimension, it is a distinct difference that there is a metal cladding (composed of a number of metals for ohmic contact and the read-out integrated circuit hybridization) in the FPA between the heavily doped gallium arsenide used as the contact layer and the ROIC; on the contrary, the front-illuminated single pixel device consists of two heavily doped contact layers separated by the QD-absorber on a semi-infinite GaAs substrate. This paper is focused on analyzing the impact of a two dimensional metal hole array structure integrated to the back-illuminated quantum dots-in-a-well (DWELL) infrared photodetectors. The metal hole array consisting of subwavelength-circular holes penetrating gold layer (2DAu-CHA) provides the enhanced responsivity of DWELL infrared photodetector at certain wavelengths. The performance of 2D-Au-CHA is investigated by calculating the absorption of active layer in the DWELL structure using a finite integration technique. Simulation results show the enhanced electric fields (thereby increasing the absorption in the active layer) resulting from a surface plasmon, a guided mode, and Fabry-Perot resonances. Simulation method accomplished in this paper provides a generalized approach to optimize the design of any type of couplers integrated to infrared photodetectors.

• Geomechanics and Engineering
• /
• 제15권5호
• /
• pp.1113-1124
• /
• 2018

Geological dynamic hazards during deep coal mining are caused by the failure of a composite system consisting of the rock and coal layers, whereas the joint in coal affects the stability of the composite system. In this paper, the compression test simulations for the rock-coal combined body with single joint in coal were conducted using $PFC^{2D}$ software and especially the effects of joint length and joint angle on strength and failure characteristics in a rock-coal combined body were analyzed. The joint length and joint angle exhibit a deterioration effect on the strength and affect the failure modes. The deterioration effect of joint length of L on the strength can be neglected with a tiny variation at ${\alpha}$ of $0^{\circ}$ or $90^{\circ}$ between the loading direction and joint direction. While, the deterioration effect of L on strength are relatively large at ${\alpha}$ between $30^{\circ}$ and $60^{\circ}$. And the peak stress and peak strain decrease with the increase of L. Additionally, the deterioration effect of ${\alpha}$ on the strength becomes larger with the increase of L. With the increase of ${\alpha}$, the peak stress and peak strain first decrease and then increase, presenting "V-shaped" curves. And the peak stress and peak strain at ${\alpha}$ of $45^{\circ}$ are the smallest. Moreover, the failure mainly occurs within the coal and no apparent failure is observed for rock. At ${\alpha}$ between $30^{\circ}$ and $60^{\circ}$, the secondary shear cracks generated in or close to the joint tips, cause the structural instability failure of the combined body. Therefore, their failure models present as a shear failure along partial joint plane direction and partially cutting across the coal body or a shear failure along the joint plane direction. However, at ${\alpha}$ of $60^{\circ}$ and L of 10 mm, the "V-shaped" shear cracks cutting across the coal body cause its final failure. While crack nucleations at ${\alpha}$ of $0^{\circ}$ or $90^{\circ}$ are randomly distributed in the coal, the failure mode shows a V-shaped shear failure cutting across the coal body.

• 천문학회보
• /
• 제38권1호
• /
• pp.36.2-36.2
• /
• 2013

The SPICA (SPace Infrared Telescope for Cosmology & Astrophysics) project is a next-generation infrared space telescope optimized for mid- and far-infrared observation with a cryogenically cooled 3m-class telescope. The focal plane instruments onboard SPICA will enable us to resolve many astronomical key issues from the formation and evolution of galaxies to the planetary formation. The FPC-S (Focal Plane Camera - Sciecne) is a near-infrared instrument proposed by Korea as an international collaboration. Owing to the capability of both low-resolution imaging spectroscopy and wide-band imaging with a field of view of $5^{\prime}{\times}5^{\prime}$, it has large throughput as well as high sensitivity for diffuse light compared with JWST. In order to strengthen advantages of the FPC-S, we propose the studies of probing population III stars by the measurement of cosmic near-infrared background radiation and the star formation history at high redshift by the discoveries of active star-forming galaxies. In addition to the major scientific targets, to survey large area opens a new parameter space to investigate the deep Universe. The good survey capability in the parallel imaging mode allows us to study the rare, bright objects such as quasars, bright star-forming galaxies in the early Universe as a way to understand the formation of the first objects in the Universe, and ultra-cool brown dwarfs. Observations in the warm mission will give us a unique chance to detect high-z supernovae, ices in young stellar objects (YSOs) even with low mass, the $3.3{\mu}$ feature of shocked circumstance in supernova remnants. Here, we report the current status of SPICA/FPC project and its extragalactic sciences.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
• /
• pp.430-430
• /
• 2008

Using multi plasma enhanced chemical vapor deposition system (Multi-PECVD), p-a-Si:H deposition layer as a $p^+$ region which was annealed by laser (Q-switched fiber laser, $\lambda$ = 1064 nm) on an n-type single crystalline Si (100) plane circle wafer was prepared as new doping method for single crystalline interdigitated back contact (IBC) solar cells. As lots of earlier studies implemented, most cases dealt with the excimer (excited dimer) laserannealing or crystallization of boron with the ultraviolet wavelength range and $10^{-9}$ sec pulse duration. In this study, the Q-switched fiber laser which has higher power, longer wavelength of infrared range ($\lambda$ = 1064 nm) and longer pulse duration of $10^{-8}$ sec than excimer laser was introduced for uniformly deposited p-a-Si:H layer to be annealed and to make sheet resistance expectable as an important process for IBC solar cell $p^+$ layer on a polished n-type Si circle wafer. A $525{\mu}m$ thick n-type Si semiconductor circle wafer of (100) plane which was dipped in a buffered hydrofluoric acid solution for 30 seconds was mounted on the Multi-PECVD system for p-a-Si:H deposition layer with the ratio of $SiH_4:H_2:B_2H_6$ = 30:120:30, at $200^{\circ}C$, 50 W power, 0.2 Torr pressure for 20 minutes. 15 mm $\times$ 15 mm size laser cut samples were annealed by fiber laser with different sets of power levels and frequencies. By comparing the results of lifetime measurement and sheet resistance relation, the laser condition set of 50 mm/s of mark speed, 160 kHz of period, 21 % of power level with continuous wave mode of scanner lens showed the features of small difference of lifetime and lowering sheet resistance than before the fiber laser treatment with not much surface damages. Diode level device was made to confirm these experimental results by measuring C-V, I-V characteristics. Uniform and expectable boron doped layer can play an important role to predict the efficiency during the fabricating process of IBC solar cells.