상시미동 측정을 통한 천부 횡파속도 연구

황윤구 ( Yoon Gu Hwang ),김기영 ( Ki Young Kim ) 대한지질공학회 2006 지질공학 Vol.16 No.4

상시미동을 이용하는 수동적 표면파 탐사를 결정질암 기반암 지역에서 실시하여, 내진설계 지반분류 기준인 30 m 깊이까지의 평균 횡파속도(Vs30)를 구하고자 연구를 수행하였다. 시험자료는 조사지 A와 B에서 삼각형 배열과 ``ㄴ``자형직각 배열로 2 ms 간격으로 4초 동안 기록하였다. 조사지 A에서 기록한 자료를 공간 자기상관 방법으로 분석하여 위상속도 스펙트럼을 작성하고, 수신기 배열의 길이 및 형태, 기록 횟수, 수신기 수 등의 주요인자들의 영향을 고찰하였다. 조사지 B에서 상시미동 기록자료의 역산을 통해서 구한 횡파속도와 근처 시추공에서 수직탄성파 방법으로 구한 결과가 대체로 일치함을 보여 상시미동을 이용한 표면파 탐사법이 Vs30을 구하는데 효율적인 방법으로 판단된다. The passive surface wave survey using microtremor is conducted in areas of crystalline rock basements to obtain average shear-wave velocity structures to 30 m deep (Vs30), on which the earthquake-resistant design standard is based. Test data were recorded at two sites with triangular and L-shaped arrays for 4 seconds with an sampling interval of 2 ms. The microtremor recorded at a site were analysed using the spatial autocorrelation method to obtain phase-velocity spectra and effects of major factors such as size and shape of array and number of record and receiver were examined. At the other site, shear-wave velocities were derived from VSP and microtremor data separately. The results from these two methods agree to each other reasonably well, indicating that the microtremor method can be an effective geophysical tool to measure Vs30.

나노 기술을 이용한 고부가가치 농산물의 융합기술 발전

황윤구(Yun-Gu Hwang) 한국식품과학회 2014 식품과학과 산업 Vol.47 No.1

거시경제 변수를 이용한 부동산 프로젝트 파이낸싱 연체율 결정 요인에 관한 연구

황윤구(Hwang, Yun-Goo),이석원(Lee, Seok-Won),송명수(Song, Myeong-Soo) 한국부동산정책학회 2018 不動産政策硏究 Vol.19 No.2

Regarding the real estate PF loans, according to the examination criteria getting nearly the same with all of the commercial banks implementing the regulations in earnest, they can bring forth the important reliability with regard to the understanding the influences of the causal variables at the time point of the loan and after the loan, the analyses in the long-term viewpoint, the decision on the variables, and the prediction of the future. Especially, regarding the real estate PF, because the size of the business and the size of the loans are considerable, when a delay regarding this has occurred, there is no choice but for the influence to have the big spreading ability in the market economy, too, including the real estate market. As such, the securing of the reliability regarding the risks is important regarding short-term and long-term aspects. As such, by making the PF data of the banks into the time series, this research had intended to find the decision factors that combine the macroeconomic factors and their causal variables. The temporal research in this research had intended to secure the recentness from after the work of the computerization of the real estate PF from the fourth quarter of 2006 until the fourth quarter of 2017 and then had intended to take a look at the data in relation to the macroscopic flows. Regarding the spatial range, it had been proceeded with from the data of the fourth quarter of 2006 based on the real estate PF loans nationwide by the K bank. To suit this, the macroeconomic indices, too, had the data that had been accumulated by the Ministry of Land, Infrastructure, and Transportation and the Bank of Korea as the objects. Regarding the real estates, according to the different appearances of the fluctuations of the prices and the market situation according to the region, it is intended to carry out a comparative analysis by distinguishing into the capital city region and the non-capital city region. regarding the theory of the multivariate time series, by proceeding with the unit root test, the cointegration test, the Granger causal relationship analysis, the setting up of the model, the shock reaction, and the dispersion decomposition, in their order, the stability regarding the time-series variables and the model had been established. And, at the same time, the influences had been empirically analyzed. It can possess the meaning that the real estate PF market can be understood and forecasted through the long-term viewpoint. And, through such a result, it can be applied in planning, too, for the predictions and the policies in the future. Despite this, regarding the limitations of this research, there is the limitation regarding the expandability of the data because the proceeding had taken place by centering on the one place of the K bank and there is the limitation that the analyses through the diverse viewpoints considering the many-sided economic indices and the others of the like had not been included. And the limitations of such analyses are the parts that must be improved through the researches in the future.

7N01 Al 합금의 미세조직 및 기계적 성질에 미치는 시효처리의 영향

김인배,황윤구,강민철,강정윤 한국열처리공학회 2000 熱處理工學會誌 Vol.13 No.2

Effect of aging treatment on the microstructures and mechanical properties of 7N01 Al alloy was investigated by differential scanning calorimetry, transmission electron microscopy, microhardness measurement and tensile test. Maximum hardness(125.7Hv) and tensile strength(447.3㎫) were obtained from the specimen aged at 120℃ for 32hrs. The major precipitation hardening phase was confirmed as coherent MgZn₂(η') phase. Microhardness changes after peakaged condition showed very large decrease upon increased aging time. This result was attributed to the high transformation rate from coherent η' to incoherent η. It was found that the precipitation sequence of 7N01 Al alloy was GP zone→metastable spherical hcp MgZn₂(η')→equilibrium rodlike hcp MgZn₂(η).

Enhancement of Stability of Quantum Dots by the Organic Treatment

박현수,김남훈,황윤구,김범성,이재원,이찬기 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.1

양자점(Quantum Dots)은 수 나노미터(nm)의 크기를 가진 0 차원(0-Dimentional) 구조의 소재로써 다양한 물리적, 전기적, 광학적 특성으로 인해 다양한 분야에 적용될 수 있다. 특히 입도제어에 따라 밴드갭(Band-gap) 조절이 가능한 Quantum Confinement Effect로 인해 다양한 에너지 밴드갭을 구현할 수 있어, 조명 및 에너지 소재로 응용할 경우 높은 연색성 및 변환효율을 달성할 수 있다. 그러나 양자점은 높은 표면에너지(Surface Energy)를 가지고 있어 산소와 수분과 같은 외부인자에 의해 특성 및 내구성이 쉽게 저하되는 문제점을 가지고 있다, 본 연구에서는 양자점의 특성 저하 문제를 해결하기 위해 양자점 표면을 유기물 표면처리 하여 양자점 특성 저하를 방지하였다. 그 결과 경과 시간에 따른 발광 특성이 유기물을 이용하여 표면처리를 실시한 양자점이 표면처리를 실시하지 않은 양자점보다 발광 특성이 개선되었음을 확인하였다.

거시경제 변수를 활용한 주택담보대출 연체율에 미치는 결정요인에 관한 연구

이석원(Lee, Seok-Won),황윤구(Hwang, Yun-Goo),윤영의(Yoon, Young-Eui) 한국부동산정책학회 2017 不動産政策硏究 Vol.18 No.3

In the second quarter of 2017, the size of the household debts has been reaching 1,388 trillion won. And, because the size of the housing mortgage loans has been closing in upon 560 trillion won, around 40.3% has been crowded in the housing demand funds. Regarding this, there is no choice but for the influence on the entire economy to be high according to the increase of the delinquency rate in case the economy worsens or the recession continues. This study intends to suggest the implications regarding the housing mortgage loans in the long-term viewpoint through the influence evaluations of the macroeconomic variables related to such housing mortgage loan delinquencies. The macroeconomic variables that were used were the housing mortgage loan delinquency rate (TOD), the price index of the average buying and selling of the real apartment transactions (APT_PRICE), the new housing mortgage loan interest rate (HINTEREST), the index of the industrial products (IIP), the amount of money in circulation (M2), the monetary amount of the housing mortgage loans (HML), the amount of the apartment transactions (TRADE), and these were unfolded in the viewpoint of the relationship with the real estate market and the currency policy. As a result of the unit root test, it appeared that, regarding the amount of the apartment transactions, the time series raw data had been maintaining the stability. And it was able to find out that the data of the remaining variables, including the housing mortgage loan delinquency rate (TOD), had been getting stabilized through the primary difference. Because, as a result of a co-integration test, at least 6 variables possess the linear, the selection of the model used the VEC model, and, regarding the optimal differential, the 1st model was selected based on the SC (Schwarz Criterion) value. As a result of taking a look at the granger causality relationship, it appeared that the variables that had the influences on the housing mortgage loan delinquency rate were the price index of the average buying and selling of the real apartment transactions (APT_PRICE), the new housing mortgage loan interest rate (HINTEREST), the index of the industrial products (IIP), the amount of money in circulation (M2), and the amount of the apartment transactions (TRADE). As a result of analyzing the VECM (Vector error correction Model) short-run equilibrium relationship, it appeared that the housing mortgage loan delinquency rate were influenced by the index of the average price of the buying and selling of the real transactions of the apartments and by the index of industrial products. As a result of a reaction to a shock, the positive (+) correlation appeared between the housing mortgage loan delinquency rate and the amount of the transactions of the apartments (TRADE) and, also, the interest rate of the new housing mortgage loan (HINTEREST). Eventually, regarding the housing mortgage loan delinquency rate, if the interest rate goes up, right away, an increase of the delinquency rate takes place. And, it appeared that, if the monetary amount of the housing mortgage loan becomes big, the delinquency rate decreases. This is because the delinquency rate has the influences on the incomes and others of the like, it can be under the control of the interest rate policies. The meaning of this research is that it investigated about the relationship with the housing mortgage loan delinquency rates by considering the indices in the real estate market and the currency policies at the same time. And, it is that, in the condition in which the scale of the housing mortgage loan having become big at present, raising the interest rate can aggravate the confusion more in the market. As a result, with regard to the proceeding with the real estate policies, the prudent and macroscopic approach is needed. And the researches on the relationships of the indices will be needed more in the macroscopic viewpoint.

국내 외 커피전문점 간 요인 특성에 관한 비교연구

김동환,안상진,전광호,황윤구 한국산업경영시스템학회 2015 한국산업경영시스템학회 학술대회 Vol.2015 No.추계

국내 외 커피전문점 간 요인특성에 따른 비교연구

김동환,안상진,전광호,황윤구 한국산업경영시스템학회 2015 한국산업경영시스템학회 학술대회 Vol.2015 No.추계

금 콜로이드 용액 처리에 따른 고려인삼의 생육, 진세노사이드 함량 및 물성 변화

성봉재,이가순,한승호,김선익,김관후,이석수,원준연,황윤구 한국약용작물학회 2014 한국약용작물학술대회 발표집 Vol.2014 No.05

금 나노입자를 처리한 홍삼의 산화스트레스 완화 및 PC-12 신경세포 보호

김지원(Ji Won Kim),조치흥(Chi Heung Cho),황윤구(Yun-Gu Hwang),박우정(Woo Jung Park),강희(Hee Kang),김대옥(Dae-Ok Kim) 한국식품과학회 2017 한국식품과학회지 Vol.49 No.2

본 연구에서는 금 나노입자 용액을 생장하는 6년근 인삼에 직접 시비해서 금 나노입자가 전이된 황금인삼을 열수 추출하여 총 페놀 함량, 총플라보노이드 함량, 산화방지능 및 신경세포 보호능을 평가하였다. 1°Bx의 황금홍삼 추출물은 총페놀과 총플라보노이드 함량이 각각 212.2 mg GAE와 3.5 mg CE였다. ABTS, DPPH 및 ORAC 법으로 측정시, 황금홍삼 추출물의 산화방지능은 각각 272.3, 141.2, 868.4 mg VCE/°Bx였다. 황금홍삼 추출물은 과산화수소로부터 유래한 세포 내 산화스트레스를 감소시켜 PC-12 신경세포의 생존율을 농도 의존적으로 증가시켰다. 또한, 황금홍삼 추출물은 신경전달물질인 아세틸콜린을 가수분해하는 AChE 및 BChE 활성을 억제하였다. 이러한 결과는 금 나노입자를 처리한 홍삼을 이용한 산화방지 및 신경손상억제 소재로 활용할 가능성을 제시하였다. Red ginseng prepared from fresh 6-year-old ginseng treated with colloidal gold nanoparticles was extracted using hot water to evaluate its total phenolic and flavonoid contents, antioxidant capacity, and neuroprotective effects. Water extract of red ginseng treated with gold nanoparticles (WERGGN) had total phenolic and total flavonoid contents of 212.2 mg gallic acid equivalents/°Bx and 3.5 mg catechin equivalents/°Bx, respectively. The antioxidant capacities of WERGGN measured using ABTS, DPPH, and ORAC assays were 272.3, 141.2, and 868.4 mg vitamin C equivalents/°Bx, respectively. The WERGGN showed protective effects on the viability of neuron-like PC-12 cells against oxidative stress induced by hydrogen peroxide in a dose-dependent manner, partly because of a reduction in intracellular oxidative stress. Acetylcholinesterase and butyrylcholinesterase, which degrade the neurotransmitter acetylcholine to terminate neurotransmission, were inhibited by treatment with WERGGN. These results suggest that WERGGN is useful as a functional material to decrease oxidative stress and neuronal damage.