• 대한기계학회논문집
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• 제19권11호
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• pp.3003-3013
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• 1995

The characteristics of the flow field in the tangentially fired furnace are presented. Experiments are conducted in the simplified cold type isothermal flow model. In the measurement of flow field, a hot wire anemometer is used. The hot wire was calibrated by lookup table method. The mean velocity field and turbulence characteristics are showed with changing the nozzle angle. In the center of the model, the low speed, unstable flow region is formed. The size and position of these regions are varied with changing the nozzle angle. It can be used as fundamental data in the design of the large furnace. From the experimental results, various turbulent characteristics of swirling flow field is obtained. And the entrainment mechanism of the jet flow field is described from the distribution of the skewness and the flatness. It can be used the raw data of approximate calculation and turbulent modelling.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제36회 춘계학술대회논문집
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• pp.363-366
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• 2011

마하 2의 초음속 풍동 장치에서 벤트 혼합기를 사용하여 혼합 연소실험을 수행하였다. 혼합실험에서는 헬륨을 사용하였고, 연소실험에서는 수소와 플라즈마 토치를 사용하여 연소 특성을 연구하였다. 혼합실험에서는 벤트 혼합기에 의해 수직분사임에도 불구하고 후류 혼합층에 많은 연료가 잔존하였다. 연소 실험의 경우 낮은 온도의 초음속 유동에서 플라즈마 토치를 사용한 점화와 연소되지 않은 연료-공기 혼합물의 충격파 유도 연소가 후류 영역에서 발생하였다. 열질식이 일어난 경우, shock train이 발생하며 이는 연소기내 연소 불안정성을 유도한다.

• The Journal of Asian Finance, Economics and Business
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• 제8권5호
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• pp.117-126
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• 2021

Microfinance focuses on economic development at a minute level. Microfinance is adopted to reduce the poverty level in the economic system. This study is conducted to investigate the microfinance institutions' outreach, its growth, and challenges faced by the Microfinance Banks (MFBs) and Microfinance Institutions (MFIs). Data is collected from MFBs and MFIs working in Muzaffarabad as well as from interviews and focus group discussions. Findings are based upon lending, headcount ratio, offers, the value of their offer, and the possible growth chances of microfinance in Muzaffarabad. In addition to this, the challenges associated with microfinance outreach have been highlighted during analysis and guidelines have been provided to the MFBs and MFIs to increase their outreach. The sector is financially unstable which is attributable to its reliance on conventional sources of funding. The industry faces several endogenous as well as exogenous challenges from its environment which obstructs its growth. Further, it helps the policymakers to work on the development of the region and provide the base for further future research work.

• Steel and Composite Structures
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• 제31권2호
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• pp.187-199
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• 2019

This paper presents the semi-analytical development of the dynamic instability behavior and the dynamic response of functionally graded (FG) cylindrical shallow shell panel subjected to different type of periodic axial compression. First, in prebuckling analysis, the stresses distribution within the panels are determined for respective loading type and these stresses are used to study the dynamic instability behavior and the dynamic response. The prebuckling stresses within the shell panel are the same as applied in-plane edge loading for the case of uniform and linearly varying loadings. However, this is not true for the case of parabolic loadings. The parabolic edge loading produces all the stresses (${\sigma}_{xx}$, ${\sigma}_{yy}$ and ${\tau}_{xy}$) within the FG cylindrical panel. These stresses are evaluated by minimizing the membrane energy via Ritz method. Using these stresses the partial differential equations of FG cylindrical panel are formulated by applying Hamilton's principal assuming higher order shear deformation theory (HSDT) and von-$K{\acute{a}}rm{\acute{a}}n$ non-linearity. The non-linear governing partial differential equations are converted into a set of Mathieu-Hill equations via Galerkin's method. Bolotin method is adopted to trace the boundaries of instability regions. The linear and non-linear dynamic responses in stable and unstable region are plotted to know the characteristics of instability regions of FG cylindrical panel. Moreover, the non-linear frequency-amplitude responses are obtained using Incremental Harmonic Balance (IHB) method.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2009년도 추계학술대회
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• pp.821-824
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• 2009

등각사상은 함수론의 기본적인 문제의 하나로 물리학, 공학 등에 응용되고 있다. 예를 들어 선박이나 비행기의 모양을 고려할 때 나타나는 유체의 문제등에 유용하게 쓰이고 있다. 본 논문에서는 단위원 내부로부터 Jordan 영역 내부에로의 수치등각사상을 구하는 문제를 다루는데 이것은 비선형 적분방정식인 Theodorsen방정식을 푸는 것으로 귀착된다. Theodorsen방정식을 구하는 해법 중 Wegmann의 방법은 계산량에 있어서 가장 유효하다고 알려져 있다. 그러나 수치실험을 통하여 난이도가 높은 문제에 있어 수렴하지 않는 문제점을 발견하게 되었다. 본 논문에서는 수렴하지 않는 불안정의 원인을 이론적으로 분석하고 저주파필터에 의하여 개선한 방법을 제안한다. 개선한 방법에 의한 수치 실험결과를 보고한다.

• 융합경영연구
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• 제11권4호
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• pp.65-76
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• 2023

Purpose: It suggests that in order to compare economic development between large cities, this paper aims to exclude factors such as GDP, trade, manpower, R&D, then present newly an analysis of others (inflation, exports, middle-class, competitiveness, digital). Research design, data, and methodology: In the period of rapid digitalization of the world, we would like to deal with different analysis factors than before. This is because digitalization and prices have the greatest impact on the region in terms of national competitiveness. Random sampling was used as the sample size of this study to generate various values for the annual income of the middle class and the competitiveness index, and the analysis method was used. This is because the income of the middle class can lead the digitalization of the country and accelerate it to standardization. Results: Based on these analysis, it is necessary to reduce the inflation rate of digitalization, it is necessary to lower inflation rates. This can be more fundamental than interest rates. If the demand for digitalization is reduced, national competitiveness, national competitiveness will lower national competitiveness. By building a hub for middle class, you can reduce this inflation rate without China's oversupply. Conclusion: This is because it is difficult to maintain competitiveness through interest rate control, as prices rise, and inflation can become unstable. This study can seek digital acceptance by the middle class as a solution to problems like the regional economic confrontation of new globalization inflation environment.

• 수완나부미
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• 제11권1호
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• pp.7-40
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• 2019

The essay reflects on the work of Adrian Lapian (1929-2011), an Indonesian scholar of archipelagic/maritime Southeast Asia and its "sea people-sea pirates-sea kings." The essay suggests that Lapian's writing mirrors navigation at sea, and the constant re-orientation and ever-changing, multiple points of view that are part of it. This is contrasted to Foucault's "panopticism" and academic desire for discipline. Taking cue from Lapian's writing and from the present author's experience of seafaring, the essay envisions Southeast Asian studies as a fluid, precarious, disorienting, even nauseating multiplicity of experiences, dialogues, and moving, unstable, and uncertain points of view; a style of learning that is less (neo)colonial, more humble, and closer to experiences in the region, than super-scholarship that imposes universalizing, panoptic standards, theories and methods (typically self-styled as "new") that reduce the particular into a specimen of the general, a cell in the Panopticon. The essay concludes with reflections on certain learning initiatives/traditions at the National University of Singapore, including seafaring voyages-experiences, encounters, and conversations that make students and scholars alike to move and see differently, to be touched, blown away, rocked, swayed, disoriented, swallowed, transformed, and feel anew their places, roots, bonds, distances, fears, blindness, powerlessness.

• 농촌계획
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• 제30권2호
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• pp.79-96
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• 2024

The purpose of this study is to analyze the factors affecting residential mobility between urban and rural. After classifying urban and rural region based on discriminatory attributes of the regions, we applied a multinomial logistic model, using the sample data of 2020 Korea Population and Housing Census. The major findings are as follows. The young highly educated in cities avoided rural. The young less educated in rural engaged in 2, 3th industries as well as agricultural industry, but remained in low-paying and unstable jobs. In addition, various classes moved to rural and rising house prices in cities pushed people to rural. Therefore, it is necessary to develop diversified regional industry models and provide opportunities for high quality and stable jobs in rural by linking industrial demand, education and jobs. Also, preserving the rural environment, settlement conditions and residential environment are needed for satisfying various needs of urban residents who migrate to rural areas. While regional policies so far have focused on maintaining the population size and promoting a population influx, rural development and population policies should be established in a way that responds to diverse population classes in an era of population decline.

• 한국환경보건학회지
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• 제21권4호
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• pp.1-9
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• 1995

This study was carried to investigate the biodegradability of phenol in the wastewater with the two sludge blanket-packed bed reactor in series. Each reactor had a dimension of 0.09 m i.d. and 1.5 m height and consisted of two regions. The lower region was a sludge blanket of 0.5 m height and the upper region was a packed-bed of 1 m height. The packed bed region was charged with ceramic raschig rings of 10 mm i.d., 15 mm o.d. and 20 mm length. The reactors were operated at 35$\circ$C and the hydraulic retention time(HRT) was maintained 24 hours. The synthetic wastewater composed of glucose and phenol as major components was fed into the reactor in a continuous mode with incereasing phenol concentration. In addition, the nutrient trace metals($Na^+, Mg^{2+}, Ca^{2+}, PO_4^{3-}, NH_4^+, Co^{2+}, Fe^{2+}$ etc.) were added for growing anaerobes. The phenol concentration of the effluent, the overall gas production, the composition of product gas, the efficiency of COD reduction and the duration of acclimation period were measured to determine the performance of the anaerobic wastewater treatment system as the phenol concentration of the influent was increased from 600 to 2400 mg//l. Successfully stable biodegradation of phenol could be achieved with the anaerobic treatment system from 600 to 1, 800 mg/l of the influent phenol concentration. The upper level of influent phenol loading was high enough to meet most of the practical requirement. The duration of acclimation increased with the phenol loading. At steady state of the influent phenol concentration of 1800 mg/l, the treatment performance indicated the phenol reduction efficiency of 99%, the COD reduction efficiency of 99% and the gas production rate of 37 l/day. At the influent phenol concentration of 2400 mg/l, however, the operation of the treatment system was noted unstable. While the concentration of methane in biogas decreased with increasing the influent phenol loading, the carbon dioxide was increased. However, the concentration of hydrogen was varied negligibly. The concentration of methane was high enough to be used as a fuel. As a result, it is suggested that anaerobic phenol wastewater treament was economical in the sense of energy recovery and wastewater treatment.

• 한국결정학회지
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• 제2권1호
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• pp.1-11
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• 1991

GaAs 단결정을 LEC법으로 성장시킬 때 종단쌍정이 자주 발생하여 문제가 된다. 종단쌍정이 발생 하면 (100) 방향의 성장축이 (221)로 바뀐다. 본 실 험에서는 (100) 방향의 성장축으로 직경 3 inch의 CaAs 단결정을 LEC법에 의해 성장시키고, SPW photo-etching법에 의해 GaAs 단결정성장에서 생성 된 striation과 edge facet를 관찰하여 상호관계를 연 구하였다. 이들의 불안정한 생성이 종단방정 발생의 원 인 이었다. Striation의 형태는 결정직경, 융액량등의 성장조건에 따라 변화하였다. 결정주변부에서는 미시적인 striation 형태의 변화가 있었는데, 이는 용액대류의 불안정에 기인한 것이었다. {lll} 면으로 구성된 edge facet은 결정주변부에서 striation의 형태가 볼록 해질 때 잘 생성되었다. 이것은 striation과 {lll} edgp facet이 이루는 각도가 작아지기 때문이었다. 종단방정은 결정축에 수직한 (110) 방향의 결정 표면에서 발생하였다. 이들은 불안정한 융액대류에 의해 생성되어 결정이 성장함에 따라 결정속으로 전파되었다. 종단방정은 {lll} edge facet의 재용융 후 재성장의 성장속도가 매우 빠를 때 발생하였다. 따라서 이러한 종단쌍정의 발생을 억제하기 위해서 는 고액계면에서의 급격한 융액대류의 변화가 생기 지 않도록 하여야 한다.