Influence of heat‑treated Al-Si coating on the weldability and microstructural inhomogeneity for hot stamped steel resistance nut projection welds

Eun‑Joon Chun,Sung‑Sang Lim,Young‑Tae Kim,Ki‑Sung Nam,김영민,Young‑Whan Park,Siva Prasad Murugan,Yeong‑Do Park 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.1

Resistance nut projection weldability of Al–Si coated hot stamped steel (HSS) was investigated under the viewpoint of weldablecurrent range and joint strength (pull-out load). The microstructural inhomogeneities in the welds were also studied inorder to elucidate the factors affecting the joint strength of the welds. The weldability of the given Al–Si coated HSS wascompared with the weldability of an identical HSS without the Al–Si coating (Al–Si coating was polished out) and Zn coateddual phase steel. The weldable current range of Al–Si coated HSS was found to be narrower than that of the other materials. Furthermore, the average pull-out load within the weldable current range of the Al–Si coated HSS was the lowest among thethree materials. The reason for poor weld mechanical property of the Al–Si coated hot-stamped steel was attributed to themicrostructural inhomogeneities such as unmixed Al–Si coating layer at the edge of the nugget and the second phase Fe3(Al,Si) intermetallic compound. The formation of Fe3(Al, Si) phase was attributed to the solidification segregation of Al and Siduring the weld solidification and was confirmed with the numerical analysis of solidification segregation.

고양 꽃 전시회의 전시디자인 특성에 관한 연구: 2007-2012년 작품을 중심으로

박은영 ( Eun Yeong Park ) 한국기초조형학회 2012 기초조형학연구 Vol.13 No.5

꽃의 소비 수준과 정원의 수준이 그 나라의 문화적 수준을 가늠하는 척도가 되고 있다. 환경·문화·예술의 화두가 계속되는 현재 지자체들은 산업축제 중에서 꽃을 주제로 한 꽃 전시회에 주목하고 있다. 이에 본 연구는 2007년에서 2012년까지 최근 6년간 개최된 고양 꽃 전시회의 전시디자인 특성에 대해 살펴보았다. 주제가 어떻게 전달되고, 표현되고, 체험되는지에 관해 주제전개, 장면구성, 층위설정의 세 가지 틀을 바탕으로 분석하고, 공간구성과 재료사용의 관점에서 그 의미를 고찰하였다. 전시디자인 기법에서 주제의 전개를 리얼리티와 메타포의 관점에서 보면 오브제가 가장 중요 수단이다. 벽과 천장을 주로 활용하고 식물은 분위기를 표현하기 위해 사용하고 있다. 장면의 구성은 회화적 풍경을 위해 바닥에 식물을 중심으로 전통적인 구도와 원근법을 이용하여 아름다운 정원을 조성하고 있다. 시적 풍경을 위해 벽과 천장을 이용하여 식물의 형태를 재배치시켜 새로운 의미로 탄생시키고 있다. 층위의 구성 차원에서 보면 틀짜기는 벽과 천장을 이용하여 컨텍스트에서 텍스트를 분리해 내기 위한 수법으로 강한 시선의 초점을 오브제를 통해 나타내며 난색계열의 강한 꽃색과 수직의 형태를 선호하고 있다. 켜만들기는 풍부한 미적체험을 위해 유사한 색의 식물을 반복하여 사용하고 식물의 질감을 중요하게 다루고 있다. 고양 꽃 전시회의 발전가능성을 제시해보면, 미적체험을 위한 오브제와 식물의 예술적 결합, 꽃의 의미와 상징성에 대한 개연성 있는 스토리의 시각적 전달, 사회적 맥락과 추세를 반영한 재료의 선택, 고양 호수공간의 어메니티 활용 등이다. The level of flower consumption and gardens plays as a yardstick to judge the level of a country`s culture. As environment, culture and art became a topic, local governments are paying their attention to flower-themed exhibitions amongst many industrial shows. This study is intended to investigate the exhibition design characteristics presented in the Goyang Flower Shows in the last six years from 2007 to 2012. To understand how subjects were delivered, expressed and experienced, the designer conducted analysis based on the three-level framework of theme development, scene composition and layer setting and investigated the significance of space organization and material use. From the perspectives of reality and metaphor, objects are the most important tool to develop theme in exhibition design. Main objects include walls and ceilings, while plants are used to create an atmosphere. In terms of scene composition, beautiful gardens were composed using traditional structures and perspective centering on plants on the ground, thereby creating a painterly landscape. To make a poetic landscape, walls and ceilings were used to reorganize the form of plants, from which new implications were derived. In terms of layer setting, framing was used as a method to separate context from text using walls and ceilings and express a strong focus of view through objects. Hot-colored flowers and vertical structures were preferred. For aesthetic experiences, layering repeatedly used plants in similar colors and gave emphasis on the texture of plants. Potential for the development of the Goyang Flower Show include: an artistic combination of objects and plants for visitors` aesthetic experiences; the delivery of probable visual stories on the meaning and symbolism of flowers; the selection of materials in consideration of social contexts and trends; and the utilization of amenities in the Goyang Lake Park.

축구선수의 Detraining과 Retraining이 혈청지질 및 호르몬농도에 미치는 영향

정정화,박재현,채종훈,성혜련,황지인,윤미숙,노금선,윤종관,윤영학,노순덕,정경숙,박일규,김은희,박현태,박상갑 대한스포츠의학회 1999 대한스포츠의학회지 Vol.17 No.1

The purpose of this study was to investigate the effects of detraining and retraining on serum lipid and hormones in soccer players. Subjects were seven male high-school soccer players. V˙O_2max was determined for each subjects by administering a treadmill test(initial speed: 90m/min, grade: 5%, increasing speed per 3 min: 30m/min). Serum lipid(T-C, TG, HDL-C LDL-C) and hormones(epinephrine, norepinephrine, growth hormones, cortisol) were assayed pre and post detraining in 10, 20, 30 days after retraining. The repeated ANOVA was used to determine significant differences. The 0.05 level of significance was as critical level for the study. The results of the study were as follows: 1. V˙O_2max(ml/min) were 3576.3±204.2ml/min pre detraining, 3234.1±198.9 ml/min post detraining. There are significant(p<.05) difference between pre and post detraining. In 10, 20, 30 days after retraining, V˙O_2max(ml/min) were 3601.4±170.9 ml/min. There were significantly(p<.05) increased in retraining periods. 2. V˙O_2max(ml/kg/min) were significantly(p<.05) decreased from 62.3±2.9 ml/kg/min to 55.9±4.7 ml/kg/min in detraining. In 10, 20, 30 days after retraining, V˙O_2max(ml/kg/min) were 62.4±3.4ml/kg/min, 62.7±2.3ml.kg/min, 67.3±7.2ml/kg/min respectively. There were significantly(p<.05) increased in retraining periods. 3. T-C were significantly (p<.05) increased from 166.6±8.5mg/dl to 175.3±10.3 mg/dl in detraining. In 10, 20, 30 days after retraining, T-C were 160.1± 3.2mg/dl, 156.7±3.7mg/dl, 140.3±9.0mg/dl. There were significantly(p<.05) decreased in retraining periods. 4. HDL-C were 61.4±6.6mg/di pre detraining, 5.3±6.6mg/dl post detraining. There are significant(p<.05) difference between pre and post detraining. In 10, 20, 30 days after retraining, HDL-C were 56.9±7.1mg/dl, 56.4±9.2mg/dl, 57.7±9.1mg/dl respectively. There were no significant difference in retraining periods. 5. The hormones(epinephrine. norepinephrine, growth hormone, cortisol) were changed as same patterns. Epinephrine were 26.0±7.0[g/ml pre detraining, 24.6±3.2pg/ml post detraining. In 10, 20, 30 days after retraining, epinephrine were 26.9±5.6pg/ml, 30.6±6.2pg/ml, 29.4±5.6pg/ml respectively. There were no significant difference in retraining periods. In conclusion, HDL-C, epinephrine, norepinephrine, growth hormone and cortisol were decreased, T-C, LDL-C and TG were increased in detraining. But HDL-C, epinephrine, norepinephrine, growth hormone and cortisol were increased, T-C, LDL-C and TG were decreased in retraining.

사용자 인식 스마트 홈 미러

최건영,고성화,김종옥,박은서,김완규,백경동,박동규 순천향대학교 부설 산업기술연구소 2021 순천향 산업기술연구소논문집 Vol.27 No.2

The Internet of Things, the core of the Fourth Industrial Revolution, is growing by incorporating various technologies into various fields. Among them, smart home systems that apply IoT technology to home environments are being actively studied. The home hub market, a means of communication for smart homes, is also developing at the same time. As the home hub market develops, security threats are also increasing accordingly. In this paper, 'Smart Home Mirror' is implemented by combining mirror and IoT technologies so that users can use them to communicate with smart home applications and other devices. To meet security issues, users in it are recognized by using face recognition technology and AES between all data communications in it is applied. The proposed device’s usefulness is approved by implementing it in smart home environments.

유아의 성격유형에 따른 놀이성에 관한 연구

박화윤,천은영 한국영유아보육학회 2004 한국영유아보육학 Vol.0 No.37

The purpose of this study is to examine personality types of young children and to determine if there is any relationship of the personality with the playfulness of young children's. For this purpose, personality tests were conducted to 5-year old Kindergarten children according to the Korean version of MMTIC. Their playfulness was also measured by Barnett's playfulness measuring instrument(1991). As a result, most children turned out to have intuitive, feeling and perceiving personalities as personality indicators. U-Band indicators were also revealed as a type of indecisive personality. In the difference of playfulness according to children's personality the preferred indicator of thinking-feeling type was found to be associated with psychological functional type of personality. A significant relationship was shown between the perceptive spontaneity and expression of joyfulness. These findings indicated that INFP and ENFP are dominant types of personality in 5-year old children, but the personality tended to be indecisive may continue to change and, thus, their playfulness shall be understood on the basis of functional types of personality.

아크릴아미드 고정 구멍갈파래에 의한 중금속 Cd(Ⅱ), Pb(Ⅱ) 이온의 흡착특성 (Ⅰ)-Column법

박광하,권영두,정영진,장은경 한국공업화학회 2004 공업화학 Vol.15 No.1

본 연구에서는 동해안 해조류인 구멍갈파래를 아크릴아미드에 고정하여, Cd(Ⅱ) 및 Pb(Ⅱ) 중금속 이온의 흡착 특성을 살펴보았다. 수순한 Ulva pertusa 및 Si-Ulva pertusa 흡착제보다는 아크릴아미드에 고정화된 Ulva pertusa의 경우 많은 양의 중금속이 흡착되었으며, Pb(Ⅱ) 이온이 Cu(Ⅱ) 이온보다 더 잘 흡착되는 것으로 나타났다. 흡착제의 농도가 작은 경우 중금속 이온의 흡착량은 pH에 큰 영향이 없었으나, 흡착제의 농도가 클 경우 중금속 이온의 흡착량은 pH에 큰 영향을 받았다. pH에 따른 중금속 이온의 흡착량은 pH 10.5 > 8.5 > 7.0 > 5.5 > 3.5 순으로 나타났다. 아크릴아미드에 고정화된 Ulva pertusa의 단위 질량에 대해 Cd(Ⅱ) 및 Pb(Ⅱ) 이온의 최대 흡착량은 각각 최대 8.73 ㎎과 13.20 ㎎으로 나타났다. 또한 Cd(Ⅱ) 및 Pb(Ⅱ) 이온의 회수율은 pH에 따라 다소 차이가 있었으나, 각각 61.3~75.5% 및 61.4~54.1%로 나타났다. 중금속 이온의 회수에 있어서 산성 조건이 알칼리성 조건보다 효율적이었으며, 본 실험에 의한 중금속 이온의 흡착 특성은 Freundlich 흡착 특성과 잘 일치하는 것으로 나타났다. Adsoprtion characteristics of Cd(II) and Pb(II: heavy metal ions onto the Acrylamide-immobilized Ulva pertusa, and algae of the eastern coastal area. was examined in this work. Much amounts of heavy metal ions were adsorbed onto the Acrylamide-immobilized than either bare Ulva pertusa or Si-Ulva pertusa. It was also observed that Pb(II) was more readily adsorbed on the algae that Cu(II). The adsorption amounts of heavy metal ions showed no great dependence on the pH value at low adsorbent concentration, but those were high dependent on pH value at high adsorbent concentration. The adsorption amounts of heavy metal ions were in the following order; pH 10.5 > 8.5 > 7.0 > 5.5 > 3.5. The maximum adsorption amounts of Cd(II) and PB(II) onto Ig of Acrylamide-immobilized Ulva pertusa were 8.73 mg and 13.20 mg, respectively. It was found that recovery yields of Cd(II) and Pb(II) ions were in the range of 61.3∼75.5% and 61.4∼54.1% depending on the pH level. In the heavy metal recovery, acidic condition was more efficient that alkaline condition. The adsorption behavior of these heavy metal ions was well matched with the Freundlich adsorption isotherm.

티타늄 상에 강유전성 barium titanate 박막 형성과 분극처리에 의한 유사체액 내에서의 calcium phosphate 생성 증진

박영준,이용렬,황규석,김은주,임용무,이기헌 대한치과기재학회 2001 대한치과재료학회지 Vol.28 No.2

This study was performed to fabricate a ferroelectric barium titanate (BaTiO₃, BTO) thin film on Ti substrate and to evaluate the effect of poling treatment for the improvement of calcium phosphate (Ca-P) formation. BTO thin-film was spin-coated on Ti substrate by dipping-pyrolysis technique using coating sol obtained by mixing Ba-naphthenate and Ti-naphthenate as starting substances. Pre-heating temperature of the BTO thin film was performed at 500℃ because organic-solvent was completely volatilized without any crystal growth, and the final heat treatment was performed at 600, 650, 700, 750, 800, 850℃, respectively. By repeating the coating and pre-heating procedure gor 20 times, homogeneous thin film of 0.7㎛ thickness could be fabricated, and it performed well during the poling treatment without breakdown. The final heating treatment of the BTO thin film at 750℃ produced a homogeneous crystalline structure without heterogeneous TiO₂formation, which was confirmed by field emission scanning electron microscope (FE-SEM) and X-ray diffraction analyser (XRD). An average grain size of 20∼30 ㎚ were confirmed by SEM observation. The final heat-treated BTO thin-films were polarized (Ep = 5 V/㎛) from 160℃ to 25℃ in heating chamber for 2 h. The negatively poled BTO thin film (N-BTO), non-poled BTO thin film (BTO), Ti substrate (Ti), and 600℃ heat-treated Ti (Ti-O) were immersed in SBF and Eagle's MEM solution for 15 days at 37℃. After the immersion period, the morphological and compositional changes of the surfaces were investigated using a FE-SEM and an energy dispersive X-ray spectrometer (EDX). After immersion in simulated body fluid (SBF), sodium chloride (Nacl) crystals were formed on Ti, Ti-O, and BTO surfaces due to anion adsorption (Cl), while Ca-P crystals were formed on N-BTO surfaces. We assumed that rapidly adsorded cations (Ca²□ ions) on the negatively charged surface at the initial stage acted as nuclei for the formation of Ca-P crystals. In MEM, sodium chloride (NaCl) was formed on Ti, and Ca-P layer including NaCl was formed on Ti-O. Weak and sparse Ca-P layers were formed on BTO, while thick, homogeneous, and dense Ca-P layer was formed on N-BTO, which was confirmed by FE-SEM and EDX. These results demonstrated that introducing a N-BTO on Ti is an effective method for the improvement of Ca-P formation in SBF and MEM. In conclusion, negatively charged ferroelectric BTO thin-film on Ti would improve the possibility of implant osseointegration.

예비 유아 교사의 자아상태 유형에 관한 연구

박화윤,최인숙,천은영 한국영유아보육학회 2003 한국영유아보육학 Vol.0 No.34

The purpose of this study is to analyze the preservice teacher' ego state type and to provide basic data for personality education and teacher training. The subjects of this study were 234 students majoring in early childhood in 2 universities and 112 students majoring in early childhood in 2 colleges of Jeonbuk province. The instrument of this study were 「Ego gram Check list」that were developed by Dusay(1977). The results of this study were as follows : 1. As compared among the grade, all groups were showed that NP type was predominant position, and both A type and FC type were showed to be a significant difference. 2. As compared between university students and college students, two Groups were also showed that NP type was predominant position, and both A type and FC type were showed to be a significant difference.

강원지역 중소기업의 환경경영 실태와 과제

전영승,박은정 한국산학경영학회 2004 산학경영연구 Vol.17 No.1

본 연구의 목적은 ISO14001 인증 취득 현황조사를 통해 강원지역 중소기업의 환경경영 실태와 과제를 파악하고 환경경영의 활성화를 위한 방안을 모색하는 것이다. 주요 결과를 요약하면 다음과 같다. 첫째, 2003년 4월 현재 우리나라의 ISO14001 인증획득 업체수는 1,215개 업체인데 비해 강원지역 중소기업의 ISO14001 인증획득 업체는 광역지방자치단체 중 최하위 수준인 26개 업체에 불과하였다. 둘째, 인증 미획득 기업들이 인증을 받지 않으려는 이유로 '인증 획득 및 유지에 소요되는 비용이 효익보다 크다'는 점을 제시하였다. 셋째, ISO14001 인증을 획득한 기업이나 ISO14001 인증 미획득 기업이나 인증을 획득한(하려는) 가장 큰 이유는 '기업의 이미지 향상'이었으며, 인증 획득기업이 환경경영시스템 도입 후 얻은 효과도 '기업의 이미지 향상'으로 나타났다. 넷째, ISO14001 인증을 획득한 기업들은 환경경영시스템을 도입할 때 문제점으로 '문서작성 및 비용에 관한 부담'과 '인력 부족'에 관한 응답이 많았다. 위와 같은 연구의 주요 결과를 바탕으로 강원지역 중소기업의 환경경영 활성화를 위한 과제와 방안을 제시하면 다음과 같다. 첫째, ISO14001 인증 미획득 기업 대부분이 ISO14001에 대한 인지도가 낮아 이에 대한 지속적이고 적극적인 홍보와 교육 및 연수제도가 필요하다는 점이다. 둘째, 환경경영 관련 인력이 부족함으로 전문 인력의 양성을 위한 교육프로그램의 실시, 보조금 지급의 확대, 상담부서 및 상담창구의 개설, 관련 정보의 데이터 베이스화나 소프트웨어의 개발이 필요하다. 셋째, 저렴한 비용과 간단한 절차를 통해 인증을 받을 수 있는 중소기업용 공적 인증제도의 신설, 혹은 단체인증제도, 공단 인증제도 등을 적극 고려할 필요가 있다. The purpose of this study is to understand the realities and the subject of environmental management for small and medium-sized companies in Gwangwon area, through surveying the present status as to acquiring the certification of ISO14001, and to seek for a plan to facilitate environmental management. Given summarizing key results, those are as follows. First, while the number of companies in our country which acquired the certification of ISO14001, amounts to 1,215 businesses as of April of 2003, the number of small and medium-sized companies in Gwangwon area which obtained the certification of ISO14001 reached only 26 businesses, the lowest level among metropolitan municipalities. Second, for the reason that companies who didn't acquire the certification, strive not to receive the certification, it did present the point that 'costs to be needed in acquiring and maintaining the certification are larger than practical benefit. Third, the biggest reason for either companies which did not acquire the certification of ISO14001 or companies which did (try to) acquire the certification of IS01400, was 'enhancement of a corporate image,' and the effect after a company who obtained the certification introduced the environmental management system, was also shown to be 'the improvement of a corporate image.' Fourth, many companies who acquired the certification of IS01400 pointed out the response related to 'burden on document creation and costs' and 'lack of manpower' as problems when introducing the environmental management system. On the basis of major results of a study as the above, given presenting the subject and a plan for activating the environmental management of small and medium-sized companies in Gwangwon area, those are as follows. First, because most of companies who did not obtain the certification of IS01400 have low recognition of ISO14001, it needs continuous and positive publicity, education and a training system. Second, it requires to carry out an educational program to nurture professional manpower due to lack of manpower relevant to environmental management, to expand payment of subsidies, to open exclusive-charge department and consulting contact, to have the relevant information be database and to develop software. Third, in order to make the certification obtained through inexpensive costs and simple procedures, it needs to positively consider the creation of public approval system for a small and medium-sized company, group approval system, industrial-complex approval system, and others.

유구치 상아질의 각 부위에 적용된 수종의 복합레진 접착제의 미세인장접착강도에 관한 연구

유정은,최영철,최성철,박재홍 大韓小兒齒科學會 2009 大韓小兒齒科學會誌 Vol.36 No.3

본 연구는 유구치 상아질의 각기 다른 부위(표층부, 심층부, 치경부)에서 복합레진 접착제의 접착강도를 비교, 평가하기 위하여 임상에서 흔히 사용하고 있는 서로 다른 4종의 접착방식(3-step total etch: 1군, 2-step total etch: 2군, 2 step self-etch: 3군, all-in-one: 4군)을 적용하고 복합 레진(Light-Core™ Core Build-Up Composite)을 적층한 후, 미세인장접착강도를 비교하였을 때 다음과 같은 결과를 얻었다. 1. 접착방식간의 비교에서 레진의 접착방식에 따른 상아질 각 부위에서의 미세인장접착강도는 제 1군이 표층부에서 뚜렷이 높았으나(p<0.05) 2, 3, 4군은 부위에 따른 차이가 없었다. 2. 부위별 미세인장접착강도를 비교하여 보았을 때 상아질 표층부에서의 미세인장접착강도는 레진의 접착 방식간에 차이가 없었으나, 심층부에서는 2군, 3군, 4군 및 1군의 순으로 나타났고(p<0.05), 치경부에서는 2군과 3군이 1군과 4군에 비하여 현저히 높았다(p<0.05). The purpose of this study was to evaluate the micro-tensile bond strength (μTBS) of four luting resin to regional dentin of human primary teeth. Dentin from non-carious primary molars were prepared from different regions(s, superficial dentin; d, deep dentin; c, cervical dentin), and divided into groups based on anatomical locations and types of luting resins(Scotchbond Multi-purpose: SB ; One-Step: as ; AdheSE Bond: ASE ; G-Bond : GB) : SB-s, SB-d, SB-c; OS-s, OS-d, OS-c; ASE-s, ASE-d, ASE-c ; GB-s, GB-d, GB-c. Luting resins were used according to the manufacturers' instructions, to bond Light-Core™ Core Build-Up Composite) to the exposed dentin specimens in the light-curing mode. After storage for 1 day, μTBS was tested at a cross-head speed of 1 mm/min. Data were analyzed with T-test and two-way ANOVA. The bonding interface and fractography analyses were performed with SEM. The results were as follows : 1. μTBS to superficial dentin was significantly higher than to deep dentin for SB(p<0.05). But there were no significant differences in regional μTBS among as, ASK GB(p>0.05). 2. There were no significant differences in μTBS to superficial dentin among each groups. But, in deep dentin, μTBS of SB-d was significantly lower than those of OS-d, ASE-d, and GB-d(p<0.05). μTBS of OS-d was significantly higher than those of GB-d(p<0.05), but there were no significant differences in μTBS of ASE-d. There were no significant differences among μTBS of ASE-d, OS-d, and GB-d.