• 중소기업융합학회논문지
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• 제4권2호
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• pp.7-12
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• 2014

본 논문에서는 3차원 광선추적 기법을 이용한 실내 환경에서의 전파특성 분석을 위한 3D 시뮬레이터를 이용한 분석 결과를 제시하였다. 지금까지 소개된 대부분의 전파특성 분석 결과들은 2차원 평면에서 거리에 따른 신호의 손실(Path Loss) 위주로 연구가 진행 되었다. 본 연구에서는 실내에서 전파특성을 분석하기 위해 다양한 ITU 모델을 사용하여 입체구조의 실내 환경에서 전파의 수신신호의 세기에 대한 분석을 수행하였다. 본 연구에서 개발된 시뮬레이터를 이용해 150MHz와 2GHz대역의 손실 특성이 비교 되었고 예상한 결과를 얻을 수 있었다. 그리고 각 수신기의 위치에서 수신 신호는 전파경로상의 벽면에서 손실되는 전력에 따라 차이가 생기기 때문에 송신기의 출력이 중요한 요인으로 분석되었다.

• KIEAE Journal
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• 제13권3호
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• pp.33-40
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• 2013

The world population is consuming more than 1/3 of the total energy for heating housings. Particularly in our country, 21% of the consumption energy is occupied by building section. Therefore, it is necessary to increase the energy efficiency in buildings, thus promoting a comfortable residential environment while minimizing energy consumption. Accordingly, this study presents considerations for implementing high-insulated and airtight passive houses. This study selected four houses with passive house design applied, performed building energy performance through PHPP2007, a German passive house design simulation program, and compared the building-specific heat loss and heat gain. As a result, the most vulnerable part to heat loss was turned out to be a window and the heat loss was caused by outer wall, roof, and ventilation. Accordingly, for the implementation of passive house, it is necessary to make a careful plan and airtight construction that are complementary to various parts through the energy performance analysis started from the design phase.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.160-167
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• 2008

The effects of squealer rim height on three-dimensional flows and aerodynamic losses downstream of a high-turning turbine rotor blade have been investigated for a typical tip gap-to-chord ratio of h/c=2.0%. The squealer rim height-to-chord ratio is changed to be $h_{st}/c$=0.00(plane tip), 1.37, 2.75, 5.51, and 8.26%. Results show that as $h_{st}/c$ increases, the tip leakage vortex tends to be weakened and the interaction between the tip leakage vortex and the passage vortex becomes less severe. The squealer rim height plays an important role in the reduction of aerodynamic loss when $h_{st}/c{\leq}2.75%$. In the case of $h_{st}/c{\geq}5.51%$, higher squealer rim cannot provide an effective reduction in aerodynamic loss. The aerodynamic loss reduction by increasing $h_{st}/c$ is limited only to the near-tip region within a quarter of the span from the casing wall.

• Corrosion Science and Technology
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• 제13권4호
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• pp.130-138
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• 2014

Wall thinning can be classified into three types: flow-accelerated corrosion, cavitation erosion and solid particle erosion. This article presents a study of solid particle erosion, which frequently causes damages to power plants' pipe system. Unlike previous studies, this study uses a mechanism to make solid particles in a fluid flow collide with pipe materials in underwater condition. Experiment is conducted in three cases of velocity according to solid-water ratio using the three types of the materials of A106B, SS400, and A6061. The experiments were performed for 30 days, and the surface morphology and hardness of the materials were examined for every 7 days. Based on the velocity change of the solid particles in a fluid flow, the surface changes, the change in the amount of erosion, the erosion rate and the variation in the hardness of carbon steel and aluminum family pipe materials can all be determined. In addition, factor-based erosion rates are verified and a wall-thinning relation function is suggested for the pipe materials.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.488-492
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• 2007

Since Equipment-Noises occurring in machine room penetrate wall-body and travel to the adjacent room in the form of air-borne sound and structure-borne sound, it is appearing as the main factor that injures a peaceful residential environment, and due to this, such noise-damage is currently increasing rapidly. Consequently, despite the measures for sound-insulation and soundproof against the equipment-noise penetrated wall-body is urgently required, but as the subjective evaluation considered for psychological response about the equipment-noise was not practiced, many dissatisfactions are still raising even after some measure was taken. On such point of view, this Research, at the spot, has actually measured the equipment-noise that had permeated various wall-bodies, and examined its physical characteristics, thence based upon this, has conducted Psycho-Acoustics Experiment and investigated the interrelation between the physical evaluation value and psychological reaction value. It is considered that such study result could be utilized as the useful material at the time of establishment of the Grading Standard for the insulation performance against the Architectural Plumbing Noise, in the future.

• 한국농촌건축학회논문집
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• 제15권4호
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• pp.17-24
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• 2013

Rural community in Korea being changed to aging community, declining population and income loss by the industrialization and the urbanization. The weak class in rural is confronted with more poorly environment. So it is needed to check the quality of the weak class's house in rural. Basically proposes of this paper is to find ways about rural housing improving and the vitality of rural community. This paper contents rural housing problems through the paper review and house repair characteristics for the weak class. Data for statics analysis were obtained from house repair support program for the weak class in Jeonnam province from 2011 to 2012. The results of this paper are as follow: First, house repair items ranking for the weak class in rural was insulation & heating, toilet, structure, indoor environment, electricity, outside and kitchen & waterproof. This result was reflected that weak class's energy bills is high ratio compared with income. Second, health facilities were improved for the socially disadvantaged's convenience in considering that most of weak class is a senior. Last, most of houses for weak class in rural are old clay wall and block wall. So these houses are reinforced the wall for structural safety.

• Journal of Microbiology and Biotechnology
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• 제30권6호
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• pp.878-884
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• 2020

Penicillium digitatum and P. italicum are the two important postharvest pathogens in citrus, causing about 90% of the total loss of citrus fruit during storage and transportation. Natural fungicides such as essential oils have been widely used instead of chemical fungicides for preventing and controlling postharvest diseases. In this research, p-anisaldehyde exhibited a strong inhibitory effect on P. digitatum and P. italicum, with the minimum inhibitory concentration and minimum fungicidal concentration values of both being 2.00 μl/ml. Additionally, p-anisaldehyde visibly inhibited both the green mold and blue mold development of citrus fruits inoculated with P. digitatum and P. italicum. The mycelia morphologies of these pathogens were greatly altered, and the membrane permeability and cell wall integrity of mycelia were severely disrupted under p-anisaldehyde treatment. These results suggest that the antifungal activity of p-anisaldehyde against P. digitatum and P. italicum can be attributed to the disruption of the cell wall integrity.

• 한국임상수의학회지
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• 제26권1호
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• pp.81-85
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• 2009

A spayed female, 8-year-old, maltese, weighing 1.84 kg with a history of acute severe vomiting, anorexia, depression for 2 day was referred. An abdominal mass was palpated with abdominal pain on physical examination. Radiographic findings included two soft tissue density masses in the mid-abdominal cavity and gas dilated colon. Ultrasonographs showed one heterogeneous hypoechoic round mass including intestinal wall. There were loss of normal wall layering and motility and absence of internal lumen of the intestinal wall. And another heterogeneous hyperechoic mass was identified to the medial side of the intestinal mass. Based on clinical signs, image findings, and the result of fine needle aspiration, intestinal obstruction due to alimentary lymphoma was diagnosed. On surgery, a cecal lymphoma and mesenteric lymphadenopathy were confirmed and the cecal mass was resected.

• 치과방사선
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• 제24권1호
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• pp.47-55
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• 1994

Post operative maxillary cyst may arise after the surgical treatment for maxillary sinusitis with the symtoms of swelling, pain, and pus discharge in the buccal region. It is examined by Waters' view, panoramic view and other intraoral radiographs, but quite variable radiologically. Most of the cyst is seen round or ovoid shape radiolucency, destruction, expansion and thinning of the lateral wall or posterior wall, and roots of the adjacent teeth may be resorbed. We studied about 117 cases of the post operative maxillary cysts which diagnosed in department of oral and maxillofacial radiology, Seoul National University Hospital. We analyzed and obtained following results. 1. These cysts occured more frequently in male than in female and the incidence is highest in the 4th and 5th decade. 2. Initial radical operation of maxillary sinus were performed mainly between the age of 10 and 45 years, and about 60% of the patients were 15 to 25 years. 3. Pain and swelling on buccal area, pus discharge, and toothache are most chief compaints, seven cases were found at routine examination without symtoms. 4. Most of these cysts were unilocular with smooth and well-defined border. 5. The majority of the cysts occurred in the anterolateral wall of maxillary sinus. 6. Dental changes of the lesional area were loss of lamina dura and root resorption, but about 55% were not changed.

• 한국디지털건축인테리어학회논문집
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• 제13권2호
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• pp.35-43
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• 2013

The green building is one of biggest factors to go the goal of energy saving and environmental conservation, "reduction of energy consumption, friendly energy technology, recycling of resource, and environmental pollution reduction technology. The purpose of these green buildings realized by the energy-saving technology such as the thermal bridge breaker(or thermal bridge block). Thermal bridges are localized elements that penetrate insulated portions of building envelope that results in heat loss. The purpose of this paper is to describe the technical interactions for patents of a thermal bridge breaker(TTB) used in green building practices, and be subject to investigation to TTB in the leading countries, that is, United State, Europe Union, Japan, and Korea. As a result, there are four TTB categories(roof, wall-slab connection, opening, footing) in house or building. The TTB categories is remarkable technology that is apparatus in slab-wall joints and sealing element of opening frame in walls.