Effect of Al and Mg Contents on Wettability and Reactivity of Molten Zn–Al–Mg Alloys on Steel Sheets Covered with MnO and SiO2 Layers

Joo‑Youl Huh,Min‑Je Hwang,Seung‑Woo Shim,Tae‑Chul Kim,Jong‑Sang Kim 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.6

The reactive wetting behaviors of molten Zn–Al–Mg alloys on MnO- and amorphous (a-) SiO2-covered steel sheets wereinvestigated by the sessile drop method, as a function of the Al and Mg contents in the alloys. The sessile drop tests werecarried out at 460 °C and the variation in the contact angles (θc) of alloys containing 0.2–2.5 wt% Al and 0–3.0 wt% Mg wasmonitored for 20 s. For all the alloys, the MnO-covered steel substrate exhibited reactive wetting whereas the a-SiO2-coveredsteel exhibited nonreactive, nonwetting (θc > 90°) behavior. The MnO layer was rapidly removed by Al and Mg contained inthe alloys. The wetting of the MnO-covered steel sheet significantly improved upon increasing the Mg content but decreasedupon increasing the Al content, indicating that the surface tension of the alloy droplet is the main factor controlling its wettability. Although the reactions of Al and Mg in molten alloys with the a-SiO2 layer were found to be sluggish, the wettabilityof Zn–Al–Mg alloys on the a-SiO2 layer improved upon increasing the Al and Mg contents. These results suggest that thewetting of advanced high-strength steel sheets, the surface oxide layer of which consists of a mixture of MnO and SiO2,withZn–Al–Mg alloys could be most effectively improved by increasing the Mg content of the alloys.

韓國産 市販 Cheese 의 揮發性 遊離脂肪酸에 關한 硏究

黃柱煥 건국대학교 1985 論文集 Vol.20 No.1

This study was conducted to investigate the volatile free fatty acid contents in the domestic market cheeses. The results are summarized as follows : 1. There was an average of pH 5.46, and nonsignificant. 2. Total volatile free fatty acid showed an average of 6.33ml, the highest (7.2ml) in sample D. 3. Volatile free fatty acid showed the highest (55.92%) in acetic acid, lowest (10.92%) in caprylic acid. Butylic acid and caproic acid represented 15.94%, 17.23%, respectively.

인터넷 활용의 변화양상과 요인 분석 : 2002년과 2005년 한국 네티즌에 대한 조사결과를 중심으로

황주성,유지연 한국정보사회진흥원 2007 정보화정책 Vol.14 No.1

본 연구는 우리나라의 인터넷 보급이 완료단계에 접어든 2002년과 3년 후인 2005년의 조사 자료를 토대로 국내 인터넷 활용의 전반적인 모습이 어떻게 변화하였고, 어떤 인구사회학적 집단이 그러한 변화를 주도하였는지를 밝히고자 하였다. 또한, 10여개의 주요 인터넷 활동별로 동일기간 동안의 변화양상과 변화주도 집단을 찾아냄으로써 인터넷 활용의 전체적인 모습과 변화추이를 살펴보았다. 분석결과, 지난 3년간 우리나라의 인터넷 활용은 이용도가 99.6%, 의존도와 일상화율도 각각 50.7%, 36.7%가 증가하여 동일기간 동안의 인터넷 접속율 22.6% 보다 전반적으로 높은 성장을 보여주었다. 성장을 주도한 인구사회학적 집단은 여성과 10, 20대가 두드러졌다. 지역의 경우 이용도와 의존도, 경험율에서는 중소도시 및 읍면지역이 상대적으로 높은 증가를 보인 반면, 일상화율에서는 오히려 서울 및 대도시지역이 더 높은 성장을 보였다. 인터넷 활동영역별로는 인터넷쇼핑, 시사정보, 일업무의 순으로 일상화율이 높았으며, 정규학습, 인터넷게임, 새로운 관계, 전자정부 등이 2002년에 비해 두 배 이상의 높은 증가율을 보였다. The study seeks to identify changes in overall picture of domestic Internet use and sociodemographic groups that led to that change based on the survey results of 2002, a period when the internet has become widely available and 2005. In addition to that, the study also examines general trends and changes in Internet use by pinpointing aspects of changes and groups leading the changes during the same period according to ten major Internet activities. As a result, Internet usage rate has increased by 99.6 percent in Korea over the last three years. Dependency rate and engagement rate have risen by 50.7 percent and 36.7 percent respectively, higher growth rates compared to Internet connection rate of 22.6 percent during the same period. The socio-demographic groups that took the lead in the growth have turned out to be women and people in their 10s and 20s. In regional perspective, small cities and rural areas have shown a relatively high growth in Internet use, dependency and experience while Seoul and the other large metropolitan areas have registered a steeper rise in engagement rate. In terms of Internet activities, e-shopping has recorded the highest engagement rate followed by current e-news and work-related use. e-school, online games, online friends and e-government have all grown twice as much as in 2002.

Graphical Analysis and Determination of Optimum Mixing Ratio of Bulking Agent for Composting of Food Waste

황은주,이주헌 대구대학교 환경기술연구소 2004 미래환경기술 Vol.1 No.1

Composting of food waste was studied in a controlled batch reactor with the addition of cooked rice as a biodegradable carbon source to investigate the effect of carbon to nitrogen (C/N) ratio control on composting. And, composting of bulking agents such as sawdust and wheat straw were tested with the addition of ammonium sulfate as a nitrogen source. As expected, biodegradation of the food waste having low C/N ratio was improved to some extent when foreign carbon was added. But, bulking agents used in this study exerted themselves slightly biodegradable carbon potential, indicating that the estimation of the dose of additional carbon considering desirable C/N ratio was not reasonable when lignocellulosic bulking material was added to food waste. Also, as another parameter for the estimation of bulking agent addition, the optimum moisture contents at different mixing ratios of bulking agent were evaluated. As a result, it was found that the optimum moisture content increased with sawdust addition meaning the C/N ratio increment. At these points, it was suggested that 78g sawdust / 100g food waste be mixed to make C/N ratio to 25 and moisture content to 56% for effective composting of the food waste studied in this paper.

優先順位를 附與한 ATM 멀티캐스트 스위치의 呼處理 構造에 關한 硏究

황성호,오주현,임해진 三陟大學校 1999 論文集 Vol.32 No.1

An ATM multicast switch which can effectively accommodate diverse classes of traffic, is the core component of broadband ISDN. In this paper, we proposed a new call scheduling algorithm assigning priority according to the quality of service under the diverse traffic environment in multicast switch. The algorithm presented in this paper is using unfairness of switch structure, and delay-sensitive traffic may be given the high priority such that it can be transmitted as soon as possible. Also, we proposed a new hardware structure for the algorithm which can be constructed with combinational logic gates and it is beneficial for high-speed operation and VLSI implementation. The results of simulation for performance evaluation show that mean waiting time of delay-sensitive call is considerably reduced.

사회복귀시설의 현황과 전망

황태연,이종국,고영,이주호,지성학 용인정신의학연구소 1997 용인정신의학보 Vol.4 No.1

청소년의 애착관계에 따른 갈등해결전략 분석

황주혜,유순화 釜山大學校 敎育硏究所 2006 敎育硏究 Vol.16 No.1

일부 제조업 사업장의 작업환경실태 및 특수건강진단에 대한 조사 연구

황주성,황규윤,안규동,이병국 순천향대학교 산업의학연구소 1997 순천향산업의학 Vol.3 No.1

The purpose of this study was to obtain information on the working environment, rate of environmental measurement over TLVs, the number of workers who were exposed to hazardous agents and, the examined rate of special health examination(SHE) in different types of industries. Authors investigate the reports on the working environmental status of the 101 industries in Cheonan area and result of SHE of those industries. The results were as follows : 1. Out of 101 industries under study, only 54 industries took special health examination. 2. While 85.3%(6,590) of 7,726 workers working in 101 industries were exposed to one or more hazardous agents, 88.4% of 5,867 workers working in 54 industries with special health examination were exposed to those agents & 75..4% of 1,859 workers working in 47 industries without any special health examination were exposed to those agents. But according to the criteria of selecting eligible workers for special health examination, only 32%(1,935/5,867) of total workers in the later industries were classified as eligible for the special health examination. 3. While rate of environment measurement of 101 industries TLVs who 25.5%, that of 54 industries with SHE was 29.8 & that of 47 industries without SHE was 16.1%, while the rate of noise and dust measurement over TLVs of 54 industries with SHE was 31.7%, and 25.3%, those of 47 industries without SHE was 13.6% & 35.6%, among 54 industries with SHE the rate of environmental measurement over TLVs was highest in clothes & leathers(47.0%) and that of foods(32.3%) and primary metal(31.3%). One the other hand, among 47 industries without SHE the rate of environmental measurement over TLVs was highest in paper & printing(44.9%) and that primary metal(15.8%), metaloid mineral(15.5%). 4. The examined rate of SHE of 54 industries was 92.7% as a whole. By type of industries the rate of primary metal(221.4%), foods(181.7%), chemicals(120.4%) were exceeded expected percent(100%) but the rate of metalloid mineral(53.0%), paper & printing(63.8%), machinery(72.2%) were far below the expected percent. 5. Only 4.7% of total workers working in 47 industries without SHE were classified as eligible workers for SHE. Among those eligible workers 48.9% were belonged to potential workers for SHE of noise. 6. The response rate of questionnaire was 70.4%(38/54) in 54 industries wirh SHE & 48.9%(23/47) in 47 industries. The necessity of environment measure was positively answer in 81.6% of 38 with SHE & 87% of 23 without SHE. On the other hand, the necessity of SHE was positively answered in 68.4% with SHE & 21.7% without SHE.

금융마크업률과 경제성장

황진영,조주현 한국경상학회, 한국국민경제학회 2004 경제연구 Vol.22 No.1

일반적으로 금융과 실물부문의 이론적 연결은 잘 정립되어 있지만 최근의 몇몇 실증분석의 결과는 다소 논쟁의 여지가 있다. 이러한 실증분석 결과의 차이는 금융억압에 대한 변수 선택의 문제점으로 지적될 수 있다. 이에 본 논문에서는 금융억압을 나타내는 또 다른 형태의 변수(혹은 측정치)로서 금융마크업률을 도입하여 그 유용성을 검토하고자 한다. 다시 말해 국가간자료를 이용하여 금융마크업률이 산출량 및 투자에 어떠한 영향을 미치는가를 실증분석을 통하여 알아보고자 한다. 여기서 금융마크업률은 예대이자율 차이를 예금이자율로 나눈 값으로 정의된다. 실증분석 결과 금융마크업률은 경제성장률 및 투자증가율에 대해 각각 통계적으로 유의한 부(-)의 효과가 있는 것으로 나타났다. 이러한 결과는 여러 다른 설명변수를 포함시키는 추정방정식이나, 복수방정식 체계 그리고 개발도상국만으로 구성된 표본 등에서도 만족하였다. 따라서 본 연구에서는 금융마크업률로 나타난 금융억압은 한 국가의 장기적인 경제성장에 방해가 될 수 있음을 제시하고 있다. The recent empirical studies on the impacts of financial repression on the real sector are controversial, mainly due to the reliability of the proxies of financial repression. Introducing the Financial Mark-Up Ratio(FMUR) as an alternative plausible measure of financial repression. an attempt is made to estimate the impacts of FMUR on output and investment growth. The FMUR is defined as the ratio of the difference between loan and deposit interest rates to deposit interest rate. Using cross-national evidence, it is found that the FMUR has negatively and significantly associated with the economic growth and the gross domestic investment growth rates. The results are robust t o the inclusion of some explanatory variables, for a few different econometric methods and for two different samples.

대덕 IT 클러스터의 구조와 특성 분석 : Taeduk Valley in Korea

황주성 한국경제지리학회 2004 한국경제지리학회지 Vol.7 No.3

본 연구는 대덕밸리의 주축을 이루는 IT벤처기업을 중심으로 형성된 대덕 IT클러스터의 구조와 특성을 분석함으로써 그것이 혁신클러스터로서의 요건을 어느 정도 갖추고 있는지를 밝히기 위해 수행되었다. 대덕 IT클러스터 엔진은 대덕연구단지내에서도 ETRI와 KAIST등 연구기관에서 스핀옵된 벤처기업들이라고 볼 수 있다. 1997년 IMF경제위기 이후 시작된 정부의 벤처육성 정책과 대덕연구단지내 정부출연연구기관의 대규모 구조조정이 1998년 이후 벤처창업을 가속화시킨 외부적인 요인으로 파악된다. 벤처기업이 일정한 규모를 형성되기 시작한 2000년도를 전후하여 초기의 개인 또는 모태기관을 중심으로 개별적으로 형성되던 네트워킹 현상이 보다 조직적, 집단적으로 표출되기 시작하였고, 이러한 네트워킹이 대덕 IT클러스터 형성을 위한 지원기관이나 공식적 모임의 모습으로 표출되고 있다. 신기술혁신 등이 활발하게 이루어지고 있는 등 혁신시너지가 나타나는 혁신 클러스터로의 발전 가능성이 높은 것으로 판단된다. 종합적으로 대전 IT클러스터는 산업군집 수준을 넘어선 상태로 판단된다. 하지만, 클러스터의 성숙과 성과를 위해서는 시장 연계와 생산기반의 미흡, 그리고 보다 실질적인 기술협력네트워크의 구축이 필요한 것으로 결론지을 수 있다. This study examines the structure and characteristics of Taeduk IT cluster emerging as the new regional cluster in Korea following the restructuring measures of the IMF. The engine of Taeduck IT cluster can be viewed as a network of small IT ventures spin-offed from major institutes of the science park such as ETRI, KAIST, and Chungnam University. When the number of IT ventures came to a critical mass in 2001, networking efforts and collective activities began to emerge through bridging organizations such as Taeduk Valley Venture Association and Taeduk-Net. The technology innovation system is based on the local area with high innovation performance and active spin-offs. Backward and forward linkages in terms of the industrial production system has been significantly localized. And also, local labour market looks like being formed. However, production system is not much developed to fully support the commercialization of innovative technological idea. Overall, Taejon IT cluster can be considered in a state in between industrial district and milieu innovateur according to the developmental model of Capello, R. It shows strength in the technology innovation system which is deeply embedded on Taeduk Research Park. The industrial production system is weak in suppliers for electronic parts such as PCBs, semiconductors, etc. But, those institutional and collective efforts from local actors are turned out to be high. Market access for commercialization and production infrastructure is considered to be the key factors for futher development of Taeduk IT cluster.