Earticle

일반적으로 지붕우수는 지표수에 비해 수질이 양호하다고 알려져 있지만, 지붕우수를 이용하기 위해서는 유출수의 수질조사가 선행되어야 한다. 본 연구에서는 지붕우수를 대상으로 유출 시간별로 수질을 조사 평가함으로서 빗물재이용을 위한 기초자료로 활용하기 위해 수행되었다. 조사내용은 일반 수질항목(pH, 전기전도도, TDS, KMnO4 소비량, BOD, SS, 경도, 암모늄이온)과 음이온 성분(불소, 염소이온, 질산성질소, 황산이온), 양이온(보론(붕소), 알루미늄, 크롬, 망간, 철, 구리, 아연, 비소, 셀레늄, 카드뮴, 수은, 납), 미생물(일반세균, 총대장균군) 및 입경분포에 대해 조사하였다. 4개월간 4번에 걸쳐 초기 우수를 포함하여 강우조건에 따라 일정 시간 간격으로 채수하여 초기 및 초기이후 수질과 유출특성을 비교 분석하였다. 조사 결과 거의 모든 수질 항목에서 초기 지붕우수가 이후의 지붕우수보다 10배 이상의 높은 농도를 가진 것으로 판명되었다. 반면 초기 이후의 지붕우수 수질은 양호하기에, 초기우수를 배제한다면 대체 상수로 이용이 가능할 것으로 판단된다.

The roof runoff generally has a relatively good water quality compared with the surface water. However, water quality should be investigated before reuse. In this study, we analyzed and evaluated water qualities of the roof runoff from March to July in 2013 in order to utilize those as the basic data for the roof runoff reuse. pH, Electric conductivity, TDS, KMnO4 consumption, BOD, SS, Hardness, ammonium ion, anion ions(F, Cl, NO3, SO4), cation ions(B, Al, Cr, Mn, He, Cu, Zn, As, Se, Cd, Hg, Pb), microorganisms(general bacteria and total coliform), and particle distribution were investigated. Samples were collected four times during the four month period by considering influence of first flush water on rainfall condition. The analytical data were evaluated between first and last flush waters and runoff characteristics. Our data shows that the water qualities of the first flush had 10 times more pollutants than those of the last flush, suggesting that the first flush water should be excluded for the roof runoff reuse.

ㅍ본 연구는 K-WISC-IV 단축형을 네 가지로 구성하고 타당도를 살펴보았다. A와 B형은 무선으로 추출된 정상아동 998명의 자료를 바탕으로 확인적 요인분석과 다중회귀분석을 통하여 구성되었다. A 단축형 공식은 (2.308×VC)+(1.805×SI)+58.688이며, B 단축형 공식은(2.211×VC)+(1.569×LN)+(1.337×MR)+(1.360×SS)+35.118이다. C 단축형은 Sattler(2001)가 제안한 ([VC+BD+SI+CD+LN]× 1.4)+30이며, D 단축형은 Crawford 등(2010)이 제안한 15/Sold×(VC+SI+BD+MR+DS+CD+SS-70)+100 이다. 정상 아동을 대상으로 한타당도 검증에서 A, B, C, D 단축형 모두가 전체 IQ와 실제 전체 IQ가 유의한 차이가 없으면서, 상관이 높았지만, B, C, D 단축형이 웩슬러의 지능 기술적 분류 일치율이 70% 이상으로 나타났다. 지적장애 아동을 대상으로 타당도를 검증했을 때는 B 단축형만이 타당한 것으로나타났으며, 지적장애 3급으로 분류하는 일치율도 83.3%로 높게 나타났다. B 단축형은 대략적인 지능을 빠른 시간 안에 파악할 때 유용하게 쓰일 것으로 생각되나, 세부적인 인지기능에 관련된 정보의 손실, 범주화 분류의 위험성과 같은 단점들이 존재하므로 항상 주의해서 사용해야 할 것으로 생각된다.

The purpose of this study was to introduce 4 short forms for K-WISC-IV and to test the validity of each short form(SF). Both SF A and B were developed based on confirmatory factor analysis and multiple regression analysis on data collected from 998 normal children. The formula for SF A was (2.308×VC)+(1.805×SI)+58.688, and that for SF B was (2.211×VC)+(1.569×L N)+(1.337×MR)+(1.360×SS)+35.118. The formula for SF C, developed by Sattler(2001), was ((VC+BD+SI+CD+ LN)×1.4)+30. Lastly, the formula for SF D, developed by Crawford et al(2010) was, 15/Sold×(VC+SI+BD+MR+DS+CD +SS-70)+100. For 998 normal children, the 4 SFs showed no significant differences between actual and estimated IQ. The SF B, C, and D proved to be valid, showing more than 70% concordance rate with Wechsler's intelligence descriptive classification. For 66 children with mild intellectual disability, only SF B showed the best results, showing no significant difference between actual and estimated IQ and 83.3% concordance rate. Therefore, SF B may be the most useful version to identify approximate IQ in a short time. However, it should be always used with cautions because of information loss of detailed cognitive functions and limitations of descriptive classification.

The turn-to-turn contact resistance of 2G high temperature superconducting (HTS) coils with metal insulation (MI) is closely related to the stability of the coils, current charging rate and delay time [1]. MI coils were fabricated using five kinds of metal tapes such as aluminum (Al) tape, brass tape, stainless steel (SS) tape, copper (Cu)-plated tape and one-sided Cu-plated SS tape. The turn-to-turn contact surface resistances of co-winding model coils using Al tape, brass tape, and SS tape were 342.6, 343.6 and 724.8 μΩ·cm2, respectively. The turn-to-turn contact resistance of the model coil using the one-sided Cu-plated SS tape was 248.8 μΩ·cm2, which was lower than that of Al and brass tape. Al or brass tape can be used to reduce contact resistance and improve the stability of the coil. Considering strength, SS tape is recommended. For strength and low contact resistance, SS tape with copper plating on one side can be used.

A Gate-All-Around (GAA) structure for 3D DRAM was fabricated using an ALD-based oxide semiconductor channel to enable low-temperature processing and suppress leakage current. Spacer engineering with ALD and dry-oxidized SiO2 effectively reduced leakage paths compared to PECVD. The use of Al2O3 as the gate insulator further improved insulation. The device demonstrated promising performance with Ion = 1.30 μA and SS = 113 mV/decade at VDS = 1.1 V, indicating its potential for next-generation memory applications.

전북 군산 및 부안 지역을 중심으로 이루어지는 새만금간척공사 수역과 그 주변 해역의 수질 및 저질 분포 특성을 구명하기 위하여 2001년 9월에 총 101개 퇴적물 시료와 69개의 해수 시료를 채취, 분석하였다. 주요 수질 항목별 평균 및 표준편차는 수온 25.51±0.68℃, 염분 29.88±5.01psu, COD 1.40±0.78 mg/L, 용존무기질소 (DIN) 0.352±0.417 mg/L, 그리고 인산인 0.027±0.023 mg/L 이었다. 영양염류 및 COD는 동진강 및 만경강 하구에서 매우 높은 농도를 보였으며, 곰소만과 새만금 입구 수역은 매우 낮은 값을 보였다. COD, 영양염류 농도 및 N/P 등은 염분과 유의적 역상관관계를 보였으며, 이는 대부분의 오염 물질이 육상 기원임을 시사하였다. 주성분 분석에 의한 수질 분포 역시 새만금 수역으로 유입되는 지류에서 높은 영양염류 및 유기물 농도를 보여 타 수역에 비하여 수질 오염도가 높았다. 퇴적물의 경우 주요 중금속류 및 일반저질항목별 농도는 알루미늄 2.28±0.92%, 카드뮴 0.61±0.27 ppm, 구리 8.95±4.06 ppm, 철 1.19±0.37%, 망간 182.31±77.45 ppm, 니켈 10.83±4.97 ppm, 납 15.20±4.35 ppm, 아연 41.34±34.62 ppm, COD 2.68±1.85 mg/g dry, AVS 0.04±0.08 mg/g dry, 강열감량 1.29±1.08%, 함수율 24.11±4.49%, 총질소 0.02±0.02% 그리고 총탄소 0.22±0.30% 이었다. 저질의 공간 분포 특성 은 수질처럼 명확하지는 않았으나, 금강하구 수역에서 전반적으로 높은 농도를 보였다. 저질 항목별 상관관계는 중금속과 유기물함량 간에 유의적 관계가 있었으며 (p＜0.05), 퇴적물내의 농축비 (enrichment factor)가 대부분 수역에서 1-2의 범위를 보여 중금속의 외부 유입이 심각하지 않은 것으로 밝혀졌다. 또한 퇴적물 내의 중금속 농도 역시 일반적인 해양 퇴적물에서 검출되는 범위 이내로 새만금 및 주변 수역의 저질 상태는 매우 양호한 것으로 판단된다.

Environmental quality(water and sediment) was analyzed in the tidal flat of Saemangum of Jeonbuk Province, the west coast of Korea, using the 101 sediment samples and 69 water samples collected in September 4~13, 2001. Major water quality parameters with the means of 69 surface water samples are as follows; 25.51±0.68 ℃ for water temperature, 29.88±5.01 for salinity, 1.40±0.78mg/L for COD, 0.352±0.417mg/L for DIN, and 0.027±0.023mg/L for phosphate, respectively. Higher values were found at the subestuary of Dongjin and Mangyung River, and lower values at the Saemangum embayment and Gomso Bay. There was a significant negative correlation between salinity and the other water quality parameters(p＜0.0001) such as COD, nutrients, SS and N/P. This correlation suggested that the major pollution sources be from terrestrial inputs through tributaries in this area. Principal component analysis clearly revealed a spatial variation of water quality; stations with higher values of nutrients and COD located subestuary of tributaries. 14 sediment quality parameters including 8 trace metals were measured using the 101 surface sediment samples. Average values for the parameters are as follows; Al 2.28±0.92%, Cd 0.61±0.27 ppm, Cu 8.95±4.06 ppm, Fe 1.19±0.37%, Mn 182.31±77.45 ppm, Ni 10.83±4.97 ppm, Pb 15.20±4.35 ppm, Zn 41.34±34.62 ppm, COD 2.68±1.85 mg/g dry, AVS 0.04±0.08 mg/g dry, IL 1.29±1.08%, water content 24.11water quality. Some higher values were found at the subestuary of Gum River and lower values at the other area. There was a significant positive correlation between the heavy metal concentrations and organic materials within the sediment(p＜0.05). Enrichment factors showed the ranges of 1~2 for most of the metals in the sediment except zinc(1~6), indicating no serious exogenous input of heavy metals in the study area. Also, the heavy metal concentrations in the sediment were within the ranges found at the natural marine environments.

攻攀場面에 노출된 후 후속공격이 증가한다는 社會的學習理論과 이와 反對로 攻擊행동이 減少된다는 傳統的 혹은 修正된 憎惡解消理論을 再評價分析하기 위하여 中立的映畫와 攻擊的映畫 등 2종의 자극 모델을 통해 81 명의 서울대학생에게 攻擊性을 측정했다. 특히 情緖誘發水準의 差異에 따른 攻擊量의 變化樣相을 관찰하고 攻繫性測定指標로서 이미 인정된 電氣자극강도와 相關지워 전기자극의 持續時間이 攻擊性의 指標로서의 可能性도 아울러 검토하였다. 그 결과 攻繫映畫를 본 피험자는 情報誘發水準에 관계없이 모두 中立映畫를 본 피험자보다 攻擊量이 많았으며, 情緒誘發水準이 높아질수록 攻擊量의 증가를 보였으며, 攻擊測定指標로서의 전기자극 持續時間은 아직 부적절한 것으로 나타났다. 따라서 暴力映盡가 社會的暴力行爲를 助長한다는 Bandura와 Walters의 주장은 지지받는 반면 攻擊映畫를 본 후 攻擊行動減少는 전혀 없었기 때문에 Feshbach 등의 憎惡解消理論은 支持받지 못했다.

This experiment aimed at investigating the effects of vicarious aggression through aggressive film, and also at finding that the relationship between the effects and the level of emotional arousal. It was designed by 2×3 factorial design. Eighty-one SNU students were initially subjected to non-arousing(control), mild-arousing and severearousing experiences. Then they viewed a. nonaggressive film a farmland sceneryete. 6 min.) and an aggressive film (boxing. 2 min. and fighting film. 4 min.). The dependent measures were the intensity andduration of electric shocks that the subjects ostensibly administered to their provacateurs(partners) whenever their partners made errors on an assigned answering task. The results revealed as follows: (1) Regardless of arousal level. Ss who observed the modeled aggression behaved more punitively than did Ss who had witnessed the non aggressive film. (2) The more aroused the Ss the more punitively they behaved. So we can say the level of aggression is dependent of the level oi emotional arousal. (3) Generally，aroused Ss responded more punitively than ded non-aroused viewers. (4) The correlations between the intensity and duration of electric shocks are different from one group to another. Because they arc very inconsistent，we have some doubt on the duration measure as an aggression index while the overall findings contradict the catharsis hypothesis both classical (Dollard, J. et al.) and revised(Feshbah, S. et al), they suggest the social learning theory of aggression by Bandrua, A. can be supported.

본 연구의 목적은 한국 웩슬러 아동 지능검사 4판(K-WISC-IV)의 단축형을 임상 집단에 적용하여 그 타당도를 살펴보는 데 있다. 연구 대상은 수도권에 소재한 종합병원 및 정신건강시설에 방문하여 종합심리평가가 의뢰된 518명의 아동·청소년으로, 평균 연령은 9.90세(SD=2.94)였다. 먼저 이들을 대상으로 국내외 연구자들에 의해 일반 집단에서의 타당도가 확인된 단축형(A 단축형: 황규태, 오상우, 2017; B 단축형: Sattler, 2001; C 단축형: Crawford 등, 2010)을 검증하였으며, 그 결과 세 가지 단축형 모두 임상 집단에서는 타당하지 않은 것으로 나타났다. 이에 확인적 요인분석과 다중회귀분석을 실시하여 수정된 단축형(D 단축형) 공식을 산출하였고, 이는 Resnick과 Entin(1971)이 제안한 단축형 지능검사의 타당도 기준을 모두 만족하였다. 그리고 A~D 단축형을 전체 연구 대상 중 ADHD로 확진 받은 사례들만 추출하여 구성한 ADHD 진단군에 적용하였을 때에도 오직 D 단축형만 그 타당도가 확인되었다. 마지막으로 본 연구의 함의와 한계점, 추후 연구에 대한 제안이 논의되었다.

This study applied the Korean-Wechsler Intelligence Scale For Children-Fourth Edition(K-WISC-IV) short forms to a clinical sample and examined the validity. The samples were 518 children and adolescents who were referred to the clinical psychology practitioners for the full battery psychological assessment from the general hospitals and the mental health facility. The group’s average age was 9.90 years old(SD=2.94). The group first took the three different types of K-WISC-IV short forms that had been proved its validity among the general groups by the various researchers in the country and abroad: the first was type A by Hwang and Oh(2017), the second was type B by Sattler(2001), and the last was type C by Crawford et al.(2010). However, the result showed that all three types were not valid in the clinical sample. Therefore, the type D was calculated through confirmatory factor analysis and multiple regression analysis. The formular of type D was (1.820*VC)+(1.552*LN)+(1.446*SS)+(1.543*MR)+34.322. The type D satisfied every validity standards that Resnick and Entin(1971) suggested. Furthermore, when the types A, B, C, and D were applied to the group of the samples who are diagnosed with ADHD(N=72), only the type D confirmed its validity. The discussion proposes this study’s implications and limits as well as the suggestions for the further studies.

SS10 microbial strain, which is isolated from soil of sweet sorghum field, was characterized and identified as Staphylococcus sp. by analysis of 16S rDNA sequence and biochemical studies, and named as Staphylococcus sp. SS10 which has high xylanase activities. The optimum temperature and pH for xylanase activity of Staphylococcus sp. SS10 were 50℃ and 10.0, respectively. The xylanase activity was strongly inhibited by Al+++. The xylanase gene was cloned from Staphylococcus sp. SS10 genomic DNA by polymerase chain reaction (PCR). The amplified PCR product was ligated with the T&A cloning vector system and the constructed plasmids were transformed into E. coli DH5α. The sequence analysis of the insert DNAs revealed the identification of a 640-bp region containing xylanase open reading frame. According to xylanase gene sequence analysis, Staphylococcus sp. SS10 had gene sequence similarity of 99% with Bacillus subtilis Xyl gene for xylanase (AB457186.1).

제올라이트로 충진된 수직 흐름 갈대 여과상에 인공하수를 주입하면서 처리효율을 조사하였다. 여과상 표면적 ㎡당 1일 314 L의 인공하수가 6시간마다 10분 동안 간헐적으로 주입되었다. 처리수의 pH는 원수보다 감소하였으며, 용존산소 농도는 원수보다 증가하였다. 수직 흐름 여과상에서 각 항목별 연중 평균 처리효율은 SS 89.9%, CODCr 86.1%, CODMn 81.2%, BOD 93.3%, T-N 34.0%, NH4 +-N, 97.3%,T-P 34.6%이었다. 처리수 중 T-N의 대부분은 NO3--N이었으며 NO2--N의 농도는 0.10 ㎎/L 이하이었다. 처리효율의 계절적 차이는 없었다. 수직 흐름 칼럼실험에서 여재인 제올라이트에 흡착된 인의 형태별 함량은 모든 깊이에서 Ca-P 〉Fe-P 〉환원가용성 Fe-P 〉Occluded p 〉Saloid P 〉Al-P 순이었다. 여과상 깊이별 Al-P를 제외한 모든 종류의 인화합물의 함량은 위층일수록 높았으며, 함량 비율은 깊이가 깊을수록 높아지는 경향이었다. 유기물 함량도 상층 (0~5 ㎝ 깊이)에 가장 높았으며, 그 이하의 깊 이에서는 별 변화가 없었다. 가동기간이 경과할수록 모든 깊이에서 유기물 함량이 증가하였다.

A sewage was treated using a vertical flow zeolite-filled reed bed. The sewage from the student dormitory of Changwon National University was fed into the reed bed for 10 minutes every 6 hours at the hydraulic load of 314 L/㎡․day. The filtering height of the reed bed was 100 ㎝ and the zeolite mixture was filled in the reed bed. The mixture consisted of the same volume of two types of zeolite ; 0.5~1 ㎜ and 1~3 ㎜ in diameter. Annual average removal efficiency was SS 89.9%, CODCr 86.1%, CODMn 81.2%, T-N 34.0%, NH4 +-N 97.3% and T-P 34.6%. T-N of effluent was mostly NO3--N and the concentration of NO2--N in effluent was lower than 0.1 mg/L. All removal efficiencies did not show a remarkable seasonal change. The ranking of phosphorous fractions fixed to the zeolite in column test was Ca-P 〉Fe-P 〉reductant soluble Fe-P〉occluded P 〉saloid P 〉Al-P at all depths of the filter. All phosphorous fractions except for Al-P reduced at deeper filter layer, while their content ratios increased at deeper filter layer. Organic matter content was the highest at the highest layer(0~5 ㎝ from the top of the filter) and only small differences were observed at the deeper filter layer than 5 ㎝ from the top. Organic matter content increased at all depths of the filter with the operating time.

고도의 경쟁 환경에서 포지셔닝 전략은 호텔 실적과 관련 된 주요 지표 중의 하나로 인식되고 있으며, 오늘날 COVID- 19 팬데믹은 호텔 브랜드가 소비자 공간 경험에 더 집중하도 록 만들었다. 객실은 손님과 가장 긴밀하고 직접적으로 연결 되는 공간이며, 객실 디자인은 소비자의 호텔 브랜드에 대한 인식에 직접적인 영향을 줄 수 있다. 본 연구는 다양한 포지 셔닝 전략에 기반하여 도심 비즈니스 호텔 객실 디자인에 대 한 중국 소비자들의 인식을 연구하였다. 우선, 문헌연구를 통 해 객실 디자인의 5차원을 추출하고, 이 5차원에 대한 128개 의 객실 디자인 요소를 도출한 후, 45명의 소비자를 대상으로 객실 디자인 요소와 5가지 포지셔닝 전략 사이의 연관성을 MDS 기법으로 조사하였다. 마지막으로 수집된 데이터를 SP SS 소프트웨어의 ALSCAL 기능을 통해 분석하였다. 그 결 과, '공간계면맵', '색상맵', '재료와 패턴맵', '조명맵', '가구 및 장식맵'과 같은 5장의 포지셔닝 맵을 제작하였으며 이를 분석하여 서로 다른 포지셔닝 전략과 객실 디자인의 특정 요소 사이의 연관성을 도출하였다. 결론으로, 본 연구는 5가지 포지셔닝 전략에 기반한 객실 디자인 요소 활용을 통하여 소 비자에게 더 나은 공간 경험을 제공하고 호텔 브랜드의 포지 셔닝 전략의 활용성을 증대하는 방안을 제시하였다.

Positioning strategy has been acknowledged as a releva nt indicator of hotel success in highly competitive enviro nment. Today, the COVID-19 pandemic is prompting hot el brands to place a greater emphasis on the consumer sp ace experience. The hotel guest room is the most intimat e and direct contact point with the customer, and its desi gn can have a significant impact on the consumer's perce ption of the hotel's brand positioning. The purpose of this study is to examine chinese consumers' perceptions of do wntown business hotel guest room design under different positioning strategies. This study used literature research to extract five dimensions of hotel room design, then inte rviewed senior designers to create 128 hotel room design factors based on these five dimensions, and then surveye d 45 consumers to correlate these hotel room design facto rs with the five positioning strategies using the MDS me thod. Finally, the acquired data was analyzed using SPSS software's ALSCAL function. Five maps were created as a result of the experiment: "Spatial Interface Map", "Colo ur Map", "Materials and Patterns Map", "Lighting Map " and "Furniture and Decoration Map." According to the ex amination of the five maps, different positioning strategie s and specific room design factors show some correlatio n. The correlation factors of guest room design under fiv e positioning strategies are provided based on the finding s of this study so that customers may have a better spati al experience and hotel brands' positioning strategies can play a better role.

용융탄산염 연료전지에서 분리판으로 사용되는 316L 스테인리스 스틸의 내식성을 향상시키기 위해 Ni과 Al을 전기도금법에 의해 코팅하였으며 열처리를 통해 스테인리스 스틸표면에 $Ni_2Al_3$, NiAl 등의 금속간화합물을 형성시켰다. $62mol\%Li_2CO_3-38mol\%K_2CO_3$ 전해질 내에서 100시간 동안 침지실험을 수행한 결과 Al의 도금두께가 $10{\mu}m$ 이상인 경우에는 내식성이 상당히 향상되었음을 확인하였다.

In the case of using high temperature by coating ceramic/metal, large stress was produced due to difference of thermal expansion coefficient between those. And then lead to delamination. In order to relaxation of the stress A1$_2$O$_3$/SS316 composite powders with $10wt.%Al_2O_3$ compositional gradient and $10wt.%Al_2O_3$ agglomerated powder were made by spray drying method. These powders were sintered to improve the strength and to be plasma sprayed in order to fabricate the FGC(functionally graded coating). The influence of gun power, working distance and Ar pressure on the microstructure of the coating layer was studied in order to optimize the plasma spray conditions. It was proven that the optimum conditions were 40kw gun power, 5cm working distance and $100ft^3/h$ Ar flow for both powders. FGC with 10 compositional steps was fabricated and the total thickness was 1.3mm. FGC was heat treated at $1100^{\circ}C$for 10hours to evaluate the heat resisting characteristics.

High velocity oxy-fuel (HVOF) spraying was used to coat Ti(Al,O)/$Al_2O_3$ powder onto the SS41 steel plate. Macrostructure of the coated specimen has been investigated by scanning electron micrograph (SEM). High temperature oxidation behavior of the coated specimen and SS41 steel have been studied. From the results of SEM observation, Ti(Al,O)/$Al_2O_3$ powder was coated well onto the substrate SS41 steel. Porosity onto the coated layer was only 0.38%. The oxidation results showed that Ti(Al,O)/$Al_2O_3$ powder coated SS41 steel have improved little oxidation resistance at $900^{\circ}C$ in air, but improved remarkably oxidation resistance at $800^{\circ}C $ in air compare to the substrate SS41 steel.

This study intends to investigate the weldability and mechanical characteristics of butt weld joints by LAFSW for dissimilar materials (Al6061-T6 and SS400). At optimum welding conditions, the tensile strength of dissimilar materials joints made by FSW is found to be lower than that of LAFSW. Due to the increase in plastic flow and formation of finer recrystallized grains at the TMAZ and SZ by laser preheating in LAFSW, the hardness in LAFSW appeared to be higher than that of FSW. Compared with FSW, finer grain size is observed and elongated grains in parent metal are deformed in the same direction around the nugget zone in TMAZ of Al6061-T6 by LAFSW. Whereas, at weld nugget zone, coarse grain size is appeared in LAFSW compared to FSW, which is owing to more plastic flow due to laser preheating effect. In dissimilar materials joints by LAFSW, ductile mode of fracture is found to occur at Al6061 side with fewer brittle particles. Mixed mode of cleavage area and ductile fracture is observed at SS400 side.

This study intends to investigate the weldability and mechanical characteristics of butt weld joints by LAFSW for dissimilar materials (Al6061-T6 and SS400). At optimum welding conditions, the tensile strength of dissimilar materials joints made by FSW is found to be lower than that of LAFSW. Due to the increase in plastic flow and formation of finer recrystallized grains at the TMAZ and SZ by laser preheating in LAFSW, the hardness in LAFSW appeared to be higher than that of FSW. Compared with FSW, finer grain size is observed and elongated grains in parent metal are deformed in the same direction around the nugget zone in TMAZ of Al6061-T6 by LAFSW. Whereas, at weld nugget zone, coarse grain size is appeared in LAFSW compared to FSW, which is owing to more plastic flow due to laser preheating effect. In dissimilar materials joints by LAFSW, ductile mode of fracture is found to occur at Al6061 side with fewer brittle particles. Mixed mode of cleavage area and ductile fracture is observed at SS400 side.

This paper was studied on the characteristics of crevice corrosion prevention of SS 400 in marine environment. In NaCl solution, polarization behavior under the crevice corrosion was investigated. And Weight loss rate of SS 400 applied cathodic protection and non cathodic protection was measured according to the NaCl concentration. The main results obtained are as follows : The weight loss rate of Al-alloy galvanic anode was increased as the concentration of NaCl solution increased by 3.5% but the concentration increased over 3.5%, that of Al-alloy galvanic anode become decreased. The protective potential of SS 400 used Al-alloy galvanic anode becomes more cathodic polarization with increasing concentration of NaCl solution. Effects of oxygen on the weight loss rate of Al-alloy sacrificial anode for cathodic protection as the concentration of 3.5% NaCl solution become sensitive than that of 0% NaCl solution.

$TiO_2$, $Al_2O_3$, and $TiO_2-Al_2O_3$ nanolaminated films were grown by atomic layer deposition (ALD) on the 316L stainless steel (SS316L) substrates at a temperature of $150^{\circ}C$. The growth kinetics of $ALD-TiO_2$ and $Al_2O_3$ thin films were systematically investigated in order to precisely control the thickness of each layers in the $TiO_2-Al_2O_3$ nanolaminated films using a high-resolution transmission electron microscopy. And, the exact deposition rates of $ALD-TiO_2$ on $Al_2O_3$ surface and $ALD-Al_2O_3$ on $TiO_2$ surface were revealed to be 0.0284 nm/cycle and 0.11 nm/cycle, respectively. At given growth conditions, the microstructures of $TiO_2$, $Al_2O_3$ and $TiO_2-Al_2O_3$ nanolaminated films were amorphous. The potentiodynamic polarization test revealed that the $TiO_2-Al_2O_3$ nanolaminated film coated SS316L had a best corrosion resistance, although all ALDcoated SS316L exhibited a clear improvement of the corrosion resistance compared with a bare SS316L.

The effect of Post-Weld Heat Treatment(PWHT) of SS400 Steel was investigated with parameters such as micro vickers hardness corrosion potential polarization behaviors galvanic current Al anode generating current Al anode weight loss etc. Hardness of each parts(HAZ, BM, WM)by PWHT is lower than that of each parts by Non Post-Weld Heat Treatment(NPWHT) However hardness of WM of HAZ part was the highest among those three parts and HAZ area were also acted as cathode without any case of heat treatment. Potential difference between each three parts by PWHT was also smaller compared to NPWHT. Therefore it is suggested that Corrosion resistance property is increased by PWHT. However both Al anode generating current and anode weight loss was also decreased by PWHT compared to NPWHT when SS400 steel is cathodically protected by Al anode.

In this paper, we have characterized the electrical properties related to gate leakage current in AlGaN/GaN MISHFETs with varying the thickness (0 to 10 nm) of $Al_2O_3$ gate insulator which also serves as a surface protection layer during high-temperature RTP. The sheet resistance of the unprotected TLM pattern after RTP was rapidly increased to $1323{\Omega}/{\square}$ from the value of $400{\Omega}/{\square}$ of the as-grown sample due to thermal damage during high temperature RTP. On the other hand, the sheet resistances of the TLM pattern protected with thin $Al_2O_3$ layer (when its thickness is larger than 5 nm) were slightly decreased after high-temperature RTP since the deposited $Al_2O_3$ layer effectively neutralizes the acceptor-like states on the surface of AlGaN layer which in turn increases the 2DEG density. AlGaN/GaN MISHFET with 8 nm-thick $Al_2O_3$ gate insulator exhibited extremely low gate leakage current of $10^{-9}A/mm$, which led to superior device performances such as a very low subthreshold swing (SS) of 80 mV/dec and high $I_{on}/I_{off}$ ratio of ${\sim}10^{10}$. The PF emission and FN tunneling models were used to characterize the gate leakage currents of the devices. The device with 5 nm-thick $Al_2O_3$ layer exhibited both PF emission and FN tunneling at relatively lower gate voltages compared to that with 8 nm-thick $Al_2O_3$ layer due to thinner $Al_2O_3$ layer, as expected. The device with 10 nm-thick $Al_2O_3$ layer, however, showed very high gate leakage current of $5.5{\times}10^{-4}A/mm$ due to poly-crystallization of the $Al_2O_3$ layer during the high-temperature RTP, which led to very poor performances.

When SS400 steel was welded with low hydrogen type and ilmennite type welding, the effect of post-weld heat treatment(PWHT) was investigated with parameters such as micro vickers hardness, corrosion potential, polarization behaviors, galvanic current, Al anode generating current and Al anode weight loss etc. Hardness of each parts(HAZ, BM, WM) by PWHT in case of low hydrogen type and ilmennite type welding was lower than that of each parts by As-welded However hardness of WM area in case of low hydrogen type and ilmennite type welding was the highest among those three parts regardless of PWHT, Whereas in case of ilmennite type welding, WM area was the highest potential among these three parts on galvanic potential series with As-welded while BM area was the highest potential among these three parts by PWHT on the contrary. And in case of low hydrogen type welding, galvanic corrosion and micro cell corrosion of welding parts was decreased with PWHT. However, It was increased with PWHT in case of ilmennite type welding. Moreover Al anode generating current and anode weight loss in case of low hydrogen type was decreased by PWHT compared to As-wedled but, which was increased than that of As-welded in case of ilmennite type welding. Therefore, it is suggested that Corrosion resistance property in case of low hydrogen type welding is increased by PWHT. However its property was devreased with PWHT in case of ilmennite type welding.