• The Journal of Asian Finance, Economics and Business
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• 제7권10호
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• pp.803-810
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• 2020

This objective of this study is to enrich the literature by the debt ratio and enterprise performance of Joint stock companies of Vietnam National Coal and Mineral Industries Holding Corporation Limited (Vinacomin). The debt ratio is an important index of capital structure, and it influences and decides the enterprise performance. Therefore, the determination of reasonable debt ratio level is beneficial to the stable operation of Vinacomin's enterprises. Based on the research conclusion about the effect on capital structure of debt ratio from domestic and foreign scholar, collecting data from 2014-2018 of Vinacomin's enterprises as a research sample, the article conducts research on the relationship between debt ratio and business performance of Vinacomin, as measured by return on total Assets. In addition, the study uses free cash flow, company size, growth opportunity, investment opportunities, operating costs to sales ratio as control variables.The study shows the debt ratio of Joint stock companies of Vietnam National Coal and Mineral Industries Holding Corporation Limited has a negative effect on the enterprise performance. Furthermore, the research results of the article are references for Vinacomin' enterprises in the course of production and business activities, determining a reasonable debt ratio, and improving the operational performance of enterprises.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집B
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• pp.447-452
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• 2000

In this study, the design of Free-Fall Simulator was carried out using concept of vertical wind tunnel. Free-Fall Simulator is not an experimental equipment but a training equipment. Therefore Free-Fall Simulator needs a large training section compared with test section of wind tunnel and has critical limit of height. These limits bring about the difficulty of design for a return passage. Due to small area ratio, the downstream flow of training section with high speed is not decelerated adequately to the fan section. High-speed flow leads to great losses in the small area ratio diffuser and corner. So design of diffusers and corners located between training section and fan section has a great effect on the Free-Fall Simulator performance. This study used an estimation method of subsonic wind tunnel performance. It considered each section of Free-Fall Simulator as an independent section. Therefore loss of one section didn't affect loss of other sections. Because losses of corner with vane and $1^{st}$ diffuser are most parts of overall Free-Fall Simulator, this study focused on the design of these sections.

• Journal of Mechanical Science and Technology
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• 제16권7호
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• pp.950-958
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• 2002

The combustion characteristics of a low NOx burner using reburning technology have been experimentally studied. The return burner usually has three distinct reaction zones which include the primary combustion zone, the reburn zone and the burnout zone by provided secondary air. NOx is mainly produced in a primary combustion zone and a certain portion of NOx can be converted to nitrogen in the rebury zone. In the burnout zone, the unburned mixtures are completely oxidated by supplying secondary air. Liquefied Petroleum Gas (LPG) was used as main and reburn fuels. The experimental parameters investigated involve the main/reburn fuel ratio, the primary/secondary air ratio, and the injection location of rebury fuel and secondary air. When the amount of return fuel reaches to the 20-30% of the total fuel used, the overall NO reduction of 50% is achieved. The secondary air is injected by two different ways including vertical and parallel injection. The injector of secondary air is located at the downstream region of furnace for a vertical-injection mode, which is also placed at the inlet primary-air injection region for a parallel-injection mode. In case of the vertical injection of the secondary air flow, the NOx formation of stoichiometric condition at a primary combustion zone is nearly independent of the rebury conditions (locations, fuel/air ratios) while the NOx emission of the fuel-lean condition is considerably influenced by the reburn conditions. In case of the parallel injection of the secondary air, the NOx emission is sensitive to the air ratio rather than the fuel ratio and the reburning process often coupled with the multiple air-staging and fuel-staging combustion processes.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1998년도 학술발표회 발표논문집
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• pp.1-7
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• 1998

To investigate the water balance in a paddy rice field with the pumping station for irrigation water supply, flow measurements and analysis on various components of water balance were carried out. The investigated area is 103.7 ha, and the irrigation water was supplied for 102 days during the total irrigation period starting from June 1. It was found that the consumption rate was increased as the growing stage was progressed. The variation of evapotranspiration rate was shown same tendency as the consumption rate, while no apparent tendency was found in infiltration rate upon different growing stages. And the ground water input to the area was predominant during the early stage of growing period, while ground water output from the study area was predominant at the end of the growing stage. The range of return flow rate, the ratio of total outflow to total inflow in every decad, was 57.6 to 85.7%. These values are slightly higher than reported values from the other investigation projects.

• 대한기계학회논문집B
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• 제27권1호
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• pp.105-116
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• 2003

The flow structure around the free end of a finite circular cylinder (FC) embedded in an atmospheric boundary layer (ABL) over open terrain was investigated experimentally with varying the free end shape. The experiments were carried out in a closed-return type subsonic wind tunnel. A finite cylinder with an aspect ratio (L/D) of 6 was mounted vertically on a long flat plate. The Reynolds number based on the cylinder diameter is about Re=7,500. The velocity fields near the FC free end were measured using the single-frame double-exposure PIV method. As a result, for the FC with a right-angled free end, there is a peculiar vortical structure, showing counter-rotating twin vortices near the FC free end. It is caused by the interaction between the entrained irrotational fluids from both sides of FC and the downwash flow from the FC free-end.

• 대한지리학회지
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• 제29권3호
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• pp.233-252
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• 1994

토지이용수문학을 위한 하나의 대안으로, 모형의 단순성, 모형변형의 용이성, 그리 고 모의된 모형으로부터 지속적인 유량 예측 능력을 지닌 Lumped모형을 이용해 토지이용 변화에 따른 수문특성의 변화를 추적하였다. Blackie(1972)의 모형을 근간으로, R1131(11-parameter, 3-storage, l-input option) 모형을 구축하였다. 연구 대상 유역분지는 케냐에 있는 Kimakia Catchement K11이며, 이곳의 토지이용은 3번 변화하였다. 3단계의 토 지이용 기간에 대해 모형을 보정한 결과, 모형유효도는 96.78%, 97.20%, 94.62%이며, 전체유 량오차는 각각 -1.78%, -3.36%, 5.32% 였다. 보정된 모형을 이용해 각 토지이용 단계별로 확장유출량을 발생시키고, 빈도해석을 시도했다. 홍수 규모가 작은 경우 식생변화에 따라 31.3%와 32.1% 정도로 홍수량이 줄어들었으나, 홍수 규모가 커짐에 따라 홍수량의 감소 정 도는 점차 작아지고 있다. 이와 같은 현상은 갈수량의 변화에서도 발견된다. 또한 식생이 어 느 정도까지 성장한 이후에는 계속된 식생 성장에도 불구하고 홍수량과 갈수량은 큰 변화가 없다.

• The Journal of Asian Finance, Economics and Business
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• 제7권10호
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• pp.697-706
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• 2020

This study investigates the relationship between related loan, ownership concentration and real estate firm performance. The data was collected from 35 real estate firms listed on Indonesia Stock Exchange from 2007 to 2012. Related loans are viewed from the angle of related lending and loan. Related lending and loan is measured by the related lending on total lending ratio and related loan on total loan ratio. Firm performance is measured by the asset turnover ratio and return on assets ratio. Ownership concentration is measured by the right cash flow. The data analysis was done with regression analysis and panel data. The results of the study found that related loans had a positive effect on sales but had no effect on profits. This supports the efficient transaction hypothesis. On the other hand, related lending has a positive effect on profits that supports opportunistic transactions. Ownership concentration moderates the effect of related loan on company's performance. The related lending are beneficial for mutually supporting activities in the real estate sector business group in Indonesia, but related loans have the potential to be used in tunneling activities. The paper contributes to the related party transaction in benefits-risks of related lending and related loan in uncertainty context.

• 대한기계학회논문집B
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• 제23권8호
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• pp.1063-1071
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• 1999

Fine grid calculations are reported for the developing turbulent flow in a curved duct of square cross-section with a radius of curvature to hydraulic diameter ratio ${\delta}=Rc/D_H=3.357 $ and a bend angle of 720 deg. A sequence of modeling refinements is introduced; the replacement of wall function by a fine mesh across the sublayer and a low Reynolds number algebraic second moment closure up to the near wall sublayer in which the non-linear return to isotropy model and the cubic-quasi-isotropy model for the pressure strain are adopted; and the introduction of a multiple source model for the exact dissipation rate equation. Each refinement is shown to lead to an appreciable improvement in the agreement between measurement and computation.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.1169-1173
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• 2007

본 연구의 시험유역은 기존에 제시되고 있는 회귀율 분석에서 각 지역별 및 업종별 다양한 회귀율을 나타내고 있어 어느 일정한 값을 결정하기 어렵고, 또한 최근 들면서 하수관거정비사업 등을 통하여 하수 차집비율이 과거에 비해 매우 높아짐에 따라 기존에 제시된 회귀율과 하수관거사업에 의해 변화되는 회귀율을 비교 분석하기위해 시험유역을 운영하였다. 물 사용량에 대한 회귀율의 정확성을 위하여 한강수계의 하남시를 대상으로 총 4개 지점에 대한 시험유역을 구성하여 생활용수의 회귀율 및 최근 환경부에서 중점적으로 추진하고 있는 하수관거 정비 사업에 따른 회귀율 변화에 대하여 계절별 회귀율을 제시하고 분석을 하였다.

• 경영과학
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• 제30권2호
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• pp.1-10
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• 2013

Case studies are made to investigate the relationship between the accuracy of energy production estimation and project feasibility indicators such as rate of return on equity (ROE) and debt service coverage ratio (DSCR) for three wind farm projects. It is found out that 1% improvement in the accuracy of energy production estimation may enhance the ROE by more than 0.5% in the case of P95, thanks to improved financing terms. AHP survey shows that MCP correlation of measured in situ wind data with long term wind speed distribution and hands-on experiences of flow analysis are more important than other factors for more precise annual energy production estimation.