• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.39-39
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• 2007

원자층 증착(Atomic Layer Deposition: ALD) 방법은 반응물질들을 펄스형태로 챔버에 공급하여 기판표면에 반응물질의 표면 포화반응에 의한 화학적 흡착과 탈착을 이용한 박막증착기술이다. ALD법은 기존의 화학적 기상증착(Chemical Vapor Deposition: CVD)과 달리 자기 제한적 반응(self-limiting reaction) 에 의하여 반응가스가 기판 표면에서만 반응하고 가스와 가스 간에는 반응하지 않는다. 따라서 박막의 조성 정밀제어가 쉽고, 파티클 발생이 없으며, 대면적의 박막 증착시 균일성이 우수하고, 박막 두께의 정밀 조절이 용이한 장점이 있다. 이러한 ALD 방식으로 3차원의 반도체 장치 구조물에 산화막 등을 형성하는 공정에서 중요한 요소 중의 하나는 전구체의 충분한 공급이다. 따라서 증기압이 높은 전구체를 선호하는 경향이 있다. 그러나 증기압이 낮은 전구체를 사용할 경우, 공급량이 부족하여 단차 도포성(step coverage)이 떨어지는 문제가 있다. 원자층 증착 공정에서 전구체를 충분히 공급하기 위해전구체 온도를 증가시키거나 전구체의 공급시간을 늘리는 방법을 사용한다. 그러나 전구체 온도를 상승시키는 경우, 전구체의 변질이나 수명을 단축시키는 문제점을 발생시킬 수 있으며. 전구체를 충분히 공급하기 위하여 전구체의 공급시간을 늘이는 방법을 사용하면, 원하는 박막을 형성하기 위하여 소요되는 공정시간과 전구체 사용량이 증가된다. 본 논문에서는 이러한 문제점을 해결하기 위해 반응기 안에서 전구체 노출 시간을 조절하는 새로운 ALD 공정을 소개한다. 특히 이러한 기술을 적용하면 나노튜브를 성장시키는데 매우 유리하다. 본 연구에서 전구체 노출 시간을 조절하기 위하여 사용된 ALD 장비는 Lucida-D200-PL (NCD Technology사)이며 (TEMA)Zr와 H2O를 사용하여 ZrO2 나노튜브를 폴리카보네이트 위에 성장시켰다. 전구체의 노출 시간은 반응기의 Stop 밸브를 이용하여 조절하였으며, SEM, TEM 등을 이용하여 나노튜브의 균일성과 단차피복성 등의 특성을 관찰하였다. 그 결과 전구체 노출시간을 조절함으로써 높은 종횡비를 갖는 나노튜브를 성장 시킬 수 있음을 확인하였다. 또한 낮은 증기압을 가지는 전구체를 이용하여도 우수한 특성의 나노튜브를 균일하게 성장시킬 수 있었다.

• Korean Journal of Materials Research
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• v.8 no.4
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• pp.368-374
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• 1998

The corrosion characteristics of zirconium alloys have been investigated in various aqueous solutions of LiOH. NaOH, KOH, RbOH. and CsOH at 3S$0^{\circ}C$. The concentrations of solutions were set to 4.3 mmol and 32.Smmol with equimolar $M^+$ and OH . The oxide characterization was performed using TEM on the samples corroded in 32. Smmol LiOH, NaOH, and KOH solution. The samples were prepared to have the same oxide thickness for the pretransition and post- transition regimes. Considering the trend of experimental data, the cation would playa major role in the corrosion process of Zr alloys in alkali hydroxide solutions. The microstructures of the oxides formed in various solutions were quite different. In LiOH solution the oxides grown in pre-transition as well as post-transition had the equiaxed structures with many pores and open grain boundaries. The oxides grown in NaOH solution had the protective columnar structures in pre-transition and the equiaxed structures with many open grain boundaries in post- transition. On the other hand. in KOH solution the columnar structure was maintained from pre- transition to post- transition. It was considered that the cation incorporation into zirconium oxide controlled the oxide characteristics and the corrosion acceleration in alkali hydroxide solutions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.396-402
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• 2021

A cross section in RC flexural members must be designed to satisfy flexural strength and ductility requirements simultaneously. In design provisions, ductile behavior is ensured by a sufficient reinforcement ratio or depth of the neutral axis. If the reinforcement ratio is less than the balanced reinforcement ratio, ductile behavior is secured, and this value is theoretically the maximum reinforcement ratio. But for a cross section with less steel, brittle failure can occur regardless of ductile behavior because of unqualifying a cracking moment. Recently, designs with a minimum steel ratio have been increasing along with the use of high-strength material, so in design provisions, a minimum amount of reinforcement is suggested. In the KCI(2012) standard, a minimum amount of reinforcement was suggested in terms of strength of steel and concrete. But in the revised KCI(2017) standard, a minimum amount of reinforcement was suggested by a relationship between the design flexural strength and cracking moment indirectly. This code can reflect the effect of cover thickness, but a material model must be defined. Therefore, the minimum amount of reinforcement in KCI(2012) and KCI(2017) was examined, and a rational review method was studied by parametric analysis.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.1
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• pp.39-46
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• 2021

The quantitative measurement of interfacial adhesion energy (Gc) of multilayer thin films for Cu interconnects was investigated using a double cantilever beam (DCB) and 4-point bending (4-PB) test. In the case of a sample with Ta diffusion barrier applied, all Gc values measured by the DCB and 4-PB tests were higher than 5 J/㎡, which is the minimum criterion for Cu/low-k integration without delamination. However, in the case of the Ta/Cu sample, measured Gc value of the DCB test was lower than 5 J/㎡. All Gc values measured by the 4-PB test were higher than those of the DCB test. Measured Gc values increase with increasing phase angle, that is, 4-PB test higher than DCB test due to increasing plastic energy dissipation and roughness-related shielding effects, which matches well interfacial fracture mechanics theory. As a result of the 4-PB test, Ta/Cu and Cu/Ta interfaces measured Gc values were higher than 5 J/㎡, suggesting that Ta is considered to be applicable as a diffusion barrier and a capping layer for Cu interconnects. The 4-PB test method is recommended for quantitative adhesion energy measurement of the Cu interconnect interface because the thermal stress due to the difference in coefficient of thermal expansion and the delamination due to chemical mechanical polishing have a large effect of the mixing mode including shear stress.

• Journal of Life Science
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• v.19 no.4
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• pp.526-531
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• 2009

This study was conducted to identify the optimum condition for dehydration and storage for maintaining the seed vigor in pelleted carrot seeds. The water content of solid materials of un-pelleted seeds was 4.9% (F.W. basis), and that of pelleted seeds was 24%. When we dehydrated pelleted seeds for 3 hr at $25^{\circ}C$, $35^{\circ}C$, and $45^{\circ}C$, all seeds were dehydrated to 5% - the same level of water content as that before pelleting. Pelleted seeds did not show any significant difference in germination from un-pelleted seeds, and neither was there any significant time or germination difference between pelleted and un-pelleted seeds at the tested dehydration temperatures. However, the $T_{50}$ value of pelleted seeds increased about 3 days larger than that of un-pelleted seeds. Germination speed of pelleted seeds in which the dehydration period was prolonged at $45^{\circ}C$ was delayed compared to those prolonged at $25^{\circ}C$ or $35^{\circ}C$ for the same period. The optimum dehydration condition, which could be applied for large scale in the industry, was dehydration at $35^{\circ}C$ for 3 hr, and the optimum storage temperature which could maintain the seed performance was $5^{\circ}C$.

• Journal of Korean Home Economics Education Association
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• v.16 no.3
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• pp.131-146
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• 2004

The Purpose of this study is to suggest strategies for environmental education through the Practical Arts(TechnologyㆍHome economics) Subject in a viewpoint of the clothing & textiles resources to resolve problems in the clothing life area. For this, this study was carried out through review of literature which is related with the consumption, the environmental problems, the environmental policies, and regulations of the government and new environmental technologies, of clothing & textiles industries and environmental education. The major findings of the study were as follows; 1) The environmental education system model in a viewpoint of the Clothing & Textiles resources was developed. This model system is consisted with interactions on school, government, industry, home and non-government organizations. Thus, the fact that Practical Arts(TechnologyㆍHome economics) Subject were the most effective subject to teaching the environmental education viewpoint of the Clothing & Textiles resources was confirmed. 2) The standards were analysed out to analyse the contents in the clothing area of the Practical Arts(TechnologyㆍHome economics) Subject. It were consist of 4 factors and 12 elements under the factors: Awareness of clothing & textile resources(clothing consumption, production of clothing & textile and environmental problems). Planning and buying of clothing(planning, buying), Management of clothing(understand of textile. human body & environment, laundering and Environmental pollution, arrangement & conservation) Recycling & exhaust of clothing(contribution, redesign, recycling, exhaust) 3) Analysing the current Practical Arts (TechnologyㆍHome economics) subject from the Environmental education in the clothing section, the environmental education related with clothing were taught the most in the middle school course, and environmental contents were concentrated in the recycling factors. but not so much on other factors. 4) After analysing the Practical Arts (TechnologyㆍHome economics) subject, the strategies were suggested for reinforcing the environmental education in the clothing of the Practical Arts(TechnologyㆍHome economics) subject.

• Korean Journal of Soil Science and Fertilizer
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• v.24
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• pp.5-38
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• 1991

비료(肥料)를 공업적(工業的)으로 제조(製造)하여 농업(農業)에 사용(使用)하기 시작(始作)한 이래(以來) 신비종(新肥種)의 개발(開發)에 대한 관심(關心)은 부단(不斷)히 계속(繼續)되어 왔으며 현재(現在)에도 어느 국가(國家)나 생산업계(生産業界)에서 개발(開發)을 위한 노력(努力)을 많이 기우리고 있음이 현실(現實)일 것이다. 어느 국가(國家)와 어느 시대(時代)에 있어서나 현존(現存) 비종(肥種)을 생산(生産)함에는 소비(消費)와 생산면(生産面)에서 상응(相應)하는 사정(事情)이 있었을 것이며 또한 미래(未來)에도 신비종(新肥種)을 개량(改良)하거나 창제(創製)함에는 여러 가지 관련문제(關聯問題)를 검토(檢討)하여 새로운 요구(要求)에 합리적(合理的)으로 부합(符合)되도록 설계(設計)해야 할 것이다. 비료(肥料)는 현대(現代) 농업(農業)에서 불가피(不可避)하게 사용(使用)되는 기본자재(基本資材)이며 세계적(世界的)으로 그 소비(消費)가 증가(增加)되나 국가별(國家別) 농업(農業)의 특수성(特殊性)에 맞추어서 비료(肥料)의 형태(形態)와 생산량(生産量)에 차이(差異)가 있게 되며 또 변화(變化), 개량(改良)될 것이다. 우리나라의 농업(農業)이 최근(最近) 급속(急速)히 변화(變化)되면서 생산수단(生産手段)과 경영(經營)에도 큰 변혁(變革)이 불가피(不可避)하게 따라야 할 것으로 판단(判斷)된다. 생산수단(生産手段)의 개량(改良)은 농산물(農産物) 생산가(生産價)를 낮추고 노력(勞力)의 투입(投入)을 줄이며 우수품질(優秀品質)의 농산물(農産物)을 안정적(安定的)으로 생산(生産)하기 위한 대응책(對應策)이 될 것이다. 비료(肥料)의 사용(使用)은 이러한 시대적(時代的) 요구(要求)에 맞추어 신비종(新肥種)이 개발(開發)되고 시용기술면(施用技術面)에서 발전(發展)이 있어야 될 것이다. 미래(未來)의 우리 나라 농업(農業)을 위하여 개발(開發)되어야 할 비종(肥種)의 형태(形態)와 그에 관련(關聯)되는 요건(要件)은 다음과 같이 요약(要約)된다. 1. 시비효율(施肥效率)을 높히기 위하여서나 성력재배(省力裁培)를 위하여 완효성(緩效性) 비료(肥料) 특히 질소비료(窒素肥料)의 신비종(新肥種) 개발(開發)이 절실(切實)히 필요(必要)하다고 판단(判斷)됨. 신비종(新肥種)은 대상작물(對象作物)의 종류(種類), 재배방식(裁培方式) 및 기계화(機械化) 상태(狀態)에 적합(適合)한 형태별(形態別)로 제조(製造)됨이 바람직함. 완효성(緩效性) 질소비료(窒素肥料)의 제조(製造)에는 화학합성(化學合成), 성형화(成形化), 흡착화(吸着化) 및 피복화(被覆化) 방식중(方式中) 성형화(成形化)에 의한 것이 최다(最多)이나 피복화(被覆化)도 재료(材料)와 기술(技術)의 발전(發展)에 따라 증가(增加)의 경향(傾向)임. 2. 현존(現存) 복합비료(複合肥料)의 토양(土壤) 및 작물(作物)에 대한 적합성(適合性)을 재검토(再檢討)하여 효율(效率)을 높히도록 개량(改良)함. 3. 소시비방식(少施肥方式)의 영농(營農)으로서 환경(環境)을 오염(汚染)으로부터 방호(防護)할 것이며 4. 작물종류(作物種類)(품종포함(品種包含)) 유전자형별(遺傳子型別) 비료감응성(肥料感應性)을 검정(檢定)하여 소시비(少施肥), 고효율(高效率)을 기(期)하도록함. 5 작물(作物)의 영양생리학(營養生理學) 분야(分野)에서도 비료외적(肥料外的)인 성장관련요인(成長關聯要因)의 작용(作用)을 연구(硏究)하여 응용(應用)의 가능성(可能性)을 추구(追究)함이 미래(未來)의 한 과제(課題)가 될 것으로 생각됨. 예(例): 유전공학적(遺傳工學的) 기법(技法)에 의한 성장인자(成長因子)의 개량(改良) 또는 시비효율(施肥效率)의 증대(增大) 작물성장(作物成長)과 미생물활동(微生物活動)과의 상호관계(相互關係) 등(等). 6. 가용(可用) 자원(資源)의 비료화(肥料化)를 위하여 타산업(他産業)의 부산물(副産物) 및 폐기물(廢棄物) (특히 유기질(有機質) 자원(資源))을 효율적(效率的)으로 재활용(再活用)하도록 함.

• Korean Chemical Engineering Research
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• v.47 no.6
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• pp.715-719
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• 2009

The phase change electrode board for the bio-information detection through electrical property response of phase change material was developed in this study. We manufactured the electrode board using Aluminum first that is widely used in conventional semiconductor device process. Without further treatment, these aluminum electrodes tend to contain voids in PETEOS(plasma enhanced tetraethyoxysilane) material that are easily detected by cross-sectional SEM(Scanning Electron Microscope). The voids can be easily attacked and transformed into holes in between PETEOS and electrodes after etch back and washing process. In order to resolve this issue of Al electrode board, we developed a electrode board manufacturing method using low resistivity TiN, which has advantages in terms of the step-coverage of phase change($Ge_2Sb_2Te_5$, GST) thin film as well as thermodynamic stability, without etch back and washing process. This TiN material serves as the top and bottom electrode in PRAM(Phase-change Random Access Memory). The good connection between the TiN electrode and GST thin film was confirmed by observing the cross-section of TiN electrode board using SEM. The resistances of amorphous and crystalline GST thin film on TiN electrodes were also measured, and 1000 times difference between the amorphous and crystalline resistance of GST thin film was obtained, which is well enough for the signal detection.

• Journal of the Korea Concrete Institute
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• v.20 no.3
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• pp.393-404
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• 2008

The approaches in many design codes for the estimation of the deflection of flexural reinforced concrete (RC) members utilize the concept of the effective moment of inertia which considers the reduction of flexural rigidity of RC beams after cracking. However, the effective moment of inertia in design codes are primarily based on the ratio of maximum moment and cracking moment of beam subjected to loading without proper consideration on many other possible influencing factors such as span length, member end condition, sectional size, loading geometry, materials, sectional properties, amount of cracks and its distribution, and etc. In this study, therefore, an experimental investigation was conducted to provide fundamental test data on the effective moment of inertia of RC beams for the evaluation of flexural deflection, and to develop a modified method on the estimation of the effective moment of inertia based on test results. 14 specimens were fabricated with the primary test parameters of concrete strength, cover thickness, reinforcement ratio, and bar diameters, and the effective moments of inertia obtained from the test results were compared with those by design codes, existing equations, and the modified equation proposed in this study. The proposed method considered the effect of the length of cracking region, reinforcement ratio, and the effective concrete area per bar on the effective moment of inertia, which estimated the effective moment of inertia more close to the test results compared to other approaches.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.5
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• pp.375-380
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• 2017

This paper reports the results of an acceleration test to predict the contact-induced failure that could occur at the cylinder-to-hole joint for the fuel rod of a sodium-cooled fast reactor (SFR). To incorporate the fuel life of the SFR currently under development at KAERI (around 35,000 h), the acceleration test method of reliability engineering was adopted in this work. A finite element method was used to evaluate the flow-induced vibration frequency and amplitude for the test parameter values. Five specimens were tested. The failure criterion during the life of the SFR fuel was applied. The S-N curve of the HT-9, the material of concern, was used to obtain the acceleration factor. As a result, a test time of 16.5 h was obtained for each specimen. It was concluded that the $B_{0.004}$ life would be guaranteed for the SFR fuel rods with 99％ confidence if no failure was observed at any of the contact surfaces of the five specimens.