• 한국세라믹학회지
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• 제34권8호
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• pp.908-913
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• 1997

Multilayer NbCxC1-x/Y2O3/Ti were sputter-coated on the alumina substrate, starting with a 0.7 ㎛ thick NbCxC1-x layer grown on substrate, followed by 0.7 ㎛ thick Y2O3 layer and 1 ㎛ thick Ti layer. To find out the optimum conditions for thickness uniformity and adhesion, sputtering works have been done with the variation of sputtering power and Ar pressure. After vacuum annealing at 950℃ and 1000℃, the thermal stability of the NbCxC1-x/Y2O3/Ti coated alumina substrates has been investigated by peel off test. The coating scheme didn't cause any debonded layer after an annealing at 950℃ for 3hrs. However, it was peeled off after annealing at 1000℃ for 3hr. It was found that the thermal stability of Al2O3/NbCxC1-x/Y2O3/Ti coating scheme changed with the NbCxC1-x composition.

• Corrosion Science and Technology
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• 제9권6호
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• pp.233-238
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• 2010

Hot-dipped Al-Mg-Si coatings to alternate Zn and Zn alloy coatings for steel were examined on metallographic structure, corrosion resistance, sacrificial ability, formation and growth of inter-metallic compounds, and mechanical properties. Near the eutectic composition of quasi-binary system of Al-$Mg_2Si$, very fine eutectic structure of ${\alpha}$-Al and $Mg_2Si$ was obtained and it showed excellent corrosion resistivity and sacrificial ability for a steel in sodium chloride solutions. Formation and growth of Al-Fe inter-metallic compounds at the interface of substrate steel and coated layer was suppressed by addition of Si. The inter-metallic compounds layer was usually brittle, however, the coating layer did not peel off as long as the thickness of the inter-metallic compounds layer was small enough. During sacrificial protection of a steel, amount of hydrogen into the steel was more than ten times smaller than that of Zn coated steel, suggesting to prevent hydrogen embrittlement. Al-Mg-Si coating is expected to apply for several kinds of high strength steels.

• 한국식품저장유통학회지
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• 제4권1호
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• pp.53-59
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• 1997

Physicochemical properties affecting on the quality of Citrus unshiu Marc. var miyagawa and C. unshiu Marc. var, okitsu according to cultivation area in Cheju were investigated. Linear correlations (r>0.9) were showed between fruit size and peel thickness. There were much difference between cultivation areas in soluble solids of C. unshiu Marc. var. okitsu. The difference were not so much in soluble solids and acid contents of citrus fruits produced at same area below 65mm of fruit diameter, but the quality of large size fruits were inferior. Brix/Acid ratio could not be index for quality evaluation, because of individual deviation. Soluble solid content of citrus fruits produced in south Cheju was higher than that produced in north Cheju. Acid content and Brix/Acid ratio of citrus fruits produced in south Cheju was lower than that produced in north Cheju. The quality of C. unshiu Marc. var. miyagawa clad not so much difference between cultivation area, but the difference of quality were recognized significantly in C. unshiu Marc. var. okitsu.

• Advances in materials Research
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• 제11권3호
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• pp.171-190
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• 2022

In this paper, the problem of interfacial stresses in steel cantilever beams strengthened with bonded composite laminates is analyzed using linear elastic theory. The analysis is based on the deformation compatibility approach, where both the shear and normal stresses are assumed to be invariant across the adhesive layer thickness. The original study in this paper carried out an analytical solution to estimate shear and peel-off stresses, as, interfacial stress analysis concentration under the uniformly distributed load and shear lag deformation. The theoretical prediction is compared with authors solutions from numerous researches. This phenomenon of deformation of the members, which gives probably approach on the study of interface of the reinforced structures, is called "shear lag effect". The resolution in this paper shows that the shear stress and the normal stress are significant and, are concentrated at the end of the composite plate of reinforcement, called "edge effect". A parametric study is carried out to show the effects of the variables of design and the physical properties of materials. This research is helpful for the understanding on mechanical behaviour of the interface and design of such structures.

• 소성∙가공
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• 제31권4호
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• pp.179-185
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• 2022

The influence of post-roll bonding heat treatment conditions such as temperature and time on the variation in the diffusion layer, generated at the bonding interface and the subsequent mechanical properties of the roll-bonded Ti grade 1/Al1050/Ti grade 1 sheets, was systematically investigated. The intermetallic compound (IMC) phase generated by post heat treatment conditions adopted in this study was obviously indexed as monolithic TiAl₃. Whereas the thickness of IMC layer generated by annealing at 500 ℃ was approximately 100 nm scale, it drastically increased above 1.5 ㎛ when annealed at 600 ℃. Uniaxial tensile and peel tests were then performed to compare mechanical properties. As a result, the bonding strength drastically increased above 7.9 N/mm by annealing at 600 ℃, which implies that proper annealing condition was a prerequisite, to improving interface bonding strength as well as global elongation properties for Ti/Al/Ti 3-ply sheet.

• 접착 및 계면
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• 제11권3호
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• pp.120-125
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• 2010

UV-curable acrylic Pressure-sensitive adhesives (Acrylic PSAs) are used in many different parts in the world. A wafer manufacture process which is based on semiconductor industry is one thing. We have used acrylic PSAs whose thickness is different from $20{\mu}m$ to $30{\mu}m$ in wafer manufacture process so far. But as wafers become more thinner, acrylic PSAs are supposed to satisfy the requirements such as proper adhesion performance. The main purpose of this research is studying proper adhesion performance and UV-curing behavior of UV-curable acrylic PSAs with very thin thickness and then determining optimized conditions to raise the efficiency of thin wafer production. Acrylic PSAs contain 2-Ethylhexyl Acrylate (2-EHA), Acrylic Acid (AA) and Butyl Acrylate (BA). Ethyl acetate (EtAc) is used as solvent. The acrylic PSAs are obtained using solvent polymerization. Thickness of UV-curable acrylic PSAs is different from $10{\sim}30{\mu}m$. By peel strength and probe tack, adhesion performance and UV curing behavior of acrylic PSA are concerned.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.58.1-58.1
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• 2010

In solar cell module manufacturing, single solar cells has to be joined electrically to strings. Copper stripes coated with tin-silver-copper alloy are joined on screen printed silver of solar cells which is called busbar. The bus bar collects the electrons generated in solar cell and it is connected to the next cell in the conventional module manufacturing by a metal stringer using conventional hot air or infrared lamp soldering systems. For thin solar cells, both soldering methods have disadvantages, which heats up the whole cell to high temperatures. Because of the different thermal expansion coefficient, mechanical stresses are induced in the solar cell. Recently, the trend of solar cell is toward thinner thickness below 180um and thus the risk of breakage of solar cells is increasing. This has led to the demand for new joining processes with high productivity and reduced error rates. In our project, we have developed a new method to solder solar cells with a laser heating source. The soldering process using diode laser with wavelength of 980nm was examined. The diode laser used has a maximum power of 60W and a scanner system is used to solder dimension of 6" solar cell and the beam travel speed is optimized. For clamping copper stripe to solar cell, zirconia(ZrO)coated iron pin-spring system is used to clamp both joining parts during a scanner system is traveled. The hot plate temperature that solar cell is positioned during lasersoldering process is optimized. Also, conventional solder joints after $180^{\circ}C$ peel tests are compared to the laser soldering methods. Microstructures in welded zone shows that the diffusion zone between solar cell and metal stripes is better formed than inIR soldering method. It is analyzed that the laser solder joints show no damages to the silicon wafer and no cracks beneath the contact. Peel strength between 4N and 5N are measured, with much shorter joining time than IR solder joints and it is shown that the use of laser soldering reduced the degree of bending of solar cell much less than IR soldering.

• 생물환경조절학회지
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• 제17권2호
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• pp.157-161
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• 2008

참외를 껍질째 먹기 위하여 착과 5일후부터 과실에 배, 사과, 포도봉지를 씌워 재배한 결과, 봉지내의 온도는 외기온에 비하여 주간에는 낮고 야간에는 높았으며 습도는 주간에는 높고 야간에는 낮았다. 무처리구에 비하여 봉지재배로 과장은 짧고 과폭은 좁고 과육두께는 얇고 과중은 가벼운 경향이었으나 처리간 차이는 없었다. 과육 및 태좌부의 당도는 봉지재배 처리구에서 낮은 경향이었으나 처리간 차이는 없었다. 그러나 과실의 당도는 봉지제거 직후 보다는 봉지제거 5일후 조사에서 높아지는 것을 알 수 있었다. 봉지재배로 과피의 경도 및 색도가 낮았다. 이와 같이 봉지재배로 과피의 경도가 낮아 껍질째 먹기는 쉬워졌으나 과피의 색도 및 당도가 낮아 금후 보완이 필요한 것으로 생각된다.

• 한국식품과학회지
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• 제25권1호
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• pp.33-38
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• 1993

제주산 금감을 소재로 원료특성, 냉동금감의 기호성, 금감잼 등의 가공식품의 제조와 특성 등을 검토하였다. 시설재배한 영파금감은 과실의 청경이 29.5 mm, 과중이 16.10g, 껍질의 두께가 4.63 mm, 단산비가 20으로서 생식용 및 가공용 금감으로서 우수하였다. 유기산 함량은 citric acid 58.27%, malic acid 32.49%, tartaric acid 9.14%, maleic acid 0.08%로서 malic acid 함량이 높아 온주밀감쥬스와는 매우 다른 특성을 나타내었다. $-18^{\circ}C$에서 6개월간 저장한 냉동금감에 대한 기호성에서 외관, 맛, 물성 모두 보통 이상으로 평가되어 좋은 것으로 판단되었으며, 냉동금감의 비타민 C 함량은 74.94 mg/100g으로 법동기간 중에 초기에 감소하다가 후기에는 큰 변화를 보이지 않았다. 오렌지쥬스만으로 제조한 잼의 경도는 1,294 g-force이며, 금감쥬스의 혼합비율이 높을수록 경도는 비례적으로 감소하였고 다른 texture parameter는 큰 차이를 보이지 않았다. 관능검사 결과, 금감쥬스를 $40{\sim}60%$, 함유한 금감잼은 오렌지쥬스 만으로 제조한 잼에 비하여 기호성이 우수하였다.

• Applied Biological Chemistry
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• 제37권3호
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• pp.161-167
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• 1994

제주지역에서 생산되는 대표적인 품종인 궁천조생과 흥진조생에 대한 품질에 관여하는 물리화학적인 특성을 분석하였고, 과일의 크기, 색깔, 생산지역에 따른 감귤의 맛 등에 대한 관능검사를 실시하였다. 수확적기에 수확한 조생온주의 가용성고형물은 $10.7{\sim}11.0$였으며, 산함량은 1.04%, 비타민 C함량은 $41.19{\sim}44.94\;mg/100\;g$였다. 당은 절반이 자당이었고, 포도당과 과당이 각각 1/4씩 함유하고 있었다. 과일크기에 따라 과중, 껍질두께, 가용성고형물, pH, 산함량, 당산비는 각각 직선적인 상관관계를 가지고 있었으며, 경도와 과육율과는 유의성이 없었다. 관능검사 결과 중간정도 크기의 감귤을 선호하며, 껍질의 색깔은 진한 홍등색일수록 선호하고 있음을 알 수 있었다. 또한, 같은 품종이라고 할지라도 재배적지에서 생산된 감귤일수록 선호도가 높아 직선적인 유의성을 보였으며, 과즙의 경우 당산비가 높을수록 선호하여 고품질 감귤생산을 위한 노력이 필요한 것으로 여겨졌다.