• 터널과지하공간
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• 제24권6호
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• pp.405-417
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• 2014

고준위폐기물처분장에서 갭채움재는 완충재와 뒷채움재의 성능을 좌우하는 중요한 공학적방벽의 구성요소이다. 본 논문에서는 갭채움재에 대한 해외 기술현황을 조사하고, 이를 통하여 갭채움재의 개념, 제조기술, 성형특성, 설치기술에 대한 연구결과들을 정리하였다. 갭채움재 개념은 처분방식과 처분개념에 따라서 나라마다 약간씩 차이가 있었다. 갭채움재 물질로는 대부분 벤토나이트를 사용하였고, 충전제로 점토를 사용하였다. 갭채움재는 펠렛, 과립상, 또는 펠렛-과립상 혼합물의 형태로 사용되었다. 갭채움재 펠렛 제조에는 정압축, 롤러압축, 압출-컷팅 방법 등이 사용되었으며, 이 중, 실험과 실제 현장에서의 펠렛 소요량을 감안하여 많은 나라들이 롤러압축방법과 압출-컷팅방법에 대한 기술 확보에 집중하였다. 펠렛 성형특성 실험결과, 펠렛의 건조밀도와 건전성은 수분함량, 구성물질, 제조방법, 펠렛 크기에 민감하였고, 제작 시 압축하중에는 상대적으로 덜 민감하였다. 갭채움재의 설치방법으로는 수직처분공 완충재 갭에서는 부어넣기(pouring) 방법, 붓고 다지기(pouring and tamping) 방법, 진동을 주며 부어넣기(pouring with vibration) 방법 등이 시도되었으며, 수평처분공 완충재와 처분터널의 뒷채움재 갭에서는 숏크리트 기술을 이용한 불어넣기(blowing by use of shotcrete technology) 방법과 오거를 이용한 정치 및 다지기(auger placement and compaction) 방법 등이 시도되었다. 그러나 이 방법들은 아직 기술적으로 초기단계에 있어 앞으로도 계속적인 연구가 이루어질 것으로 예상되었다.

• KSTLE International Journal
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• 제3권1호
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• pp.60-67
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• 2002

Wear on the tube-to-spring contact is investigated experimentally, The vibration of the tube causes the wear while the springs support it As for the supporting conditions, the contacting normal farce of 5 N,0 N and the gap of 0.1 mm are applied. The gap condition is for considering the influence of simultaneous impacting and sliding on wear. The wear volume and depth decreases in the order of the 5 N,0 N and the gap conditions. This is explained from the contact geometry of the spring, which is convex of smooth contour, The contact shear force is regarded smaller in the case of the gap existence compared with the other conditions. The wear mechanism is considered from SEM observation of the worn surface. The variation of the normal contact traction is analysed using the finite element analysis to estimate the slip displacement range on the contact with consulting the fretting map.

• Corrosion Science and Technology
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• 제10권5호
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• pp.180-188
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• 2011

In the present study, denting corrosion experiments were performed as a function of crevice gap size (50, 100 and 200 ${\mu}m$) in a solution containing 3,500 ppm NaCl + 0.2 M $CuCl_2$ (pH = 3 adjusted by HCl). The effects of chloride ion concentrations (3, 3,500 and 35,000 ppm as NaCl) were also outlined with two different crevice gap sizes (100, 200 ${\mu}m$). In addition, the effect of NiB on the denting corrosion was also investigated in a solution of 35,000 ppm NaCl + 0.2 M $CuCl_2$ (pH = 3 adjusted by HCl). The results showed that denting rate increased with the increasing crevice gap size at an initial stage and became nearly constant afterwards. As the concentration of chloride ion increased, the denting rate also increased. However, the addition of a NiB powder of 4 g/L in to the acid-chloride solution was observed to suppress the denting rate significantly.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 학술대회 논문집 전문대학교육위원
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• pp.88-93
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• 2002

$Zn_{0.5}Cd_{0.5}Al_{2}Se_{4}$ and $Zn_{0.5}Cd_{0.5}Al_{2}Se_{4}:Co^{2+}$ + single crystals were grown by CTR method. The grown single crystals have defect chalcopyrite structure with lattice constant a= 5.5966A. c= 10.8042${{\AA}}$ for the pure. a= 5.6543${{\AA}}$. c= 10.8205${{\AA}}$ for the Co-doped single crystal. respectively. The optical energy band gap was given as indirect band gap. The optical energy band gap was decreased according to add of Co-impurity. Temperature dependence of optical energy band gap was fitted well to the Varshni equation. From this relation. we can deduced the entropy. enthalpy and heat capacity. Also. we can observed the Co-impurity optical absorption peaks assigned to the $Co^{2+}$ ion sited at the $T_d$ symmetry lattice and we consider that they were attributed to the electron transitions between energy levels of ions.

• 한국전기전자재료학회논문지
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• 제16권7호
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• pp.593-598
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• 2003

In this paper, 3rd overtone mode energy-trapped filter using modified PbTiO$_3$ system ceramics was manufactured to apply for intermediate frequency(IF) SMD type fillet with splitted electrode and gap size. To investigate the effects of splitted electrode and gap size on filter characteristics of 3rd overtone mode energy-trapped filter, ceramic wafers were fabricated by etching splitted rectangular electrode size(b$\times$d) of b=0.4, 0.6, 0.8, 1mm, d=0.3, 0.4, 0.5, 0.6mm and gap size(c) c=0.2, 0.3, 0.4, 0.6mm, respectively. And then, SMD type ceramic filter were fabricated with the size of 3.7$\times$3.1$\textrm{mm}^2$. SMD type ceramic filter with the size of b=0.8mm, d=0.4mm and gap(c)=0.4mm, which showed insertion loss of 2.951dB, 3dB bandwidth of 54.7kHz and 20dB stop bandwidth of 129.27kHz, was suitable for IF bandpass filter application.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권7호
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• pp.275-281
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• 2003

$Zn_{0.5}Cd_{0.5}Al_{2}Se_{4}$ and $Zn_{0.5}Cd_{0.5}Al_{2}Se_{4}$:$Co^{2+}$ single crystals were grown by CTR method. The grown single crystals have defect chalcopyrite structure with lattice constant a=5.5966$\AA$, c=10.8042$\AA$ for the pure, a=5.6543$\AA$, c=10.8205$\AA$ for the Co-doped single crystal, respectively. The optical energy band gap was given as indirect band gap. The optical energy band gap was decreased according to add of Co-impurity Temperature dependence of optical energy band gap was fitted well to the Varshni equation. From this relation, we can deduced the entropy, enthalpy and heat capacity. Also, we can observed the Co-impurity optical absorption peaks assigned to the $Co^{2+}$ ion sited at the $T_{d}$ symmetry lattice and we consider that they were attributed to the electron transitions between energy levels of ions.

• 한국진공학회지
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• 제3권1호
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• pp.130-137
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• 1994

SbSBr, BiSBr, SbSBr : Co, BiSBr : Co, SbSBr : Ni 및 BiSBr : Ni 단결정을 수직 Bridgman 방법으로 성장시켰다. 성장된 단결정의 구조는 orthorhombic 구조이며 광학적 energy band gap 구조는 간접적이형이었고 energy gap의 온도의존성은 일차 및 이차 상전이점에서 anomalous 한 특성이 나 타 났다. 불순물로 첨가한 cobalt와 nickel은 Td 대칭점에 Co2+ ion, Co3+ ion 및 Ni2+ ion으로 위치하며 이들 ion의 energy 준위간의 전자전이에 의하여 불순물 광흡수 peak들이 나타난다.

• 대한전자공학회논문지SD
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• 제38권5호
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• pp.338-346
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• 2001

온도에 따른 반도체 에너지갭의 변화를 디지털 영상처리를 이용해 직접 측정하는 적외선 영상기법을 제안하고 있다. 본 방법은 반도체 에너지갭의 온도계수를 경제적이고 간단하게 평가할 수 있도록 한다. 본 기법의 핵심 구성 부품은 다색광원기(Polychromator), 프레임 그래버가 내장된 컴퓨터 및 가변 온도 저온유지장치(Cryostat)이다. 방법의 타당성을 검증하기 위해 LEC 방법으로 제조한 GaAs에 시험적으로 행한 실험은 온도 계수가 이론 모델에서 구한 값과 전반적으로 잘 일치함을 보여 주었다.

• 한국전기전자재료학회논문지
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• 제11권6호
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• pp.442-446
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• 1998

$\alpha$--sulfur single crystal which has orthorohmbic structure was grown using Bridgman method. The indirect optical energy band gap of this crystal are 2.65 and 2.82 eV at 10 and 300K, respectively. The wavelengths of photoluminecence(PL) peaks are 543 and 596 nm at 10k, By thermally stimulated current (TSC) method, two electron traps($D_1,D_2$) located at 0/23 and 0.43eV below the conduction band and a hole trap(A) located at 0.31 eV above the valence band are observed. PL mechanism of $\alpha$-sulfur single crystal is analyzed using the values of optical energy band gap at 10k two electron traps and a hole trap.

• 전기학회논문지P
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• 제51권3호
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• pp.137-141
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• 2002

CdS and $CdS:Co^{2+}$ single crystals were grown by CTR method using iodine as transport material. The grown single crystals have defect chalcopyrite structure with direct band gap. The optical energy band gap was decreased according to add of Co-impurity. We can observed the Co-impurity optical absorption peaks assigned to the $Co^{2+}$ ion sited at the $T_d$ symmetry lattice and we consider that they were attributed to the electron transitions between energy levels of ions.