• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.2219-2226
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• 2003

Two perforated plates are placed in parallel and staggered arrangements with a gap distance of 2 times of the hole diameter, and initial crossflow passes between the plates. Both the injection and effusion hole diameters are 10 mm, and the Reynolds number based on the hole diameter and hole-to-hole pitch are fixed to 10,000 and 6 times of the hole diameter, respectively. To investigate the effect of crossflow, the flow rate of crossflow is changed from 0.2 to 2 times of that of the impinging jet. A naphthalene sublimation method is used to determine the local heat/mass transfer coefficients on the upward facing surface of the effusion plate. With the initial crossflow, the heat/mass transfer rates on the effusion (target) plate decrease as the velocity of crossflow increases, since the crossflow induces the locally low transfer regions formed at the mid-way between the effusion holes. However, the impingement/effusion cooling with crossflow presents higher heat/mass transfer rates than the array jet impingement cooling with the same initial crossflow.

• 대한기계학회논문집B
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• 제26권1호
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• pp.101-109
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• 2002

Two perforated plates are used to investigate local heat/mass transfer characteristics in an impingement/effusion cooling system. A naphthalene sublimation method is conducted to determine the local heat/mass transfer coefficients on the upward facing surface of the effusion plate. Two plates are placed in parallel position with gap distances of 1, 2, 4 and 6 times of effusion hole diameter. The effects of hole arrangements of the plates are studied fur staggered, square, and hexagonal arrays. The experiments are conducted at Reynolds number of 10,000 based on the effusion hole diameter. The results show that the smaller hole size in the staggered array has the higher transfer coefficients on the stagnation region due to the formation of higher momentum flows through the impingement holes. In the square array, heat/mass transfer on the target plate is more uniform as the number of impingement holes increases. High and uniform heat/mass transfer coefficients are obtained for the hexagonal array.

• 원예과학기술지
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• 제29권1호
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• pp.74-76
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• 2011

An interspecific hybrid lily cultivar 'Green Star' was bred in 2005 at the National Institute of Horticultural and Herbal Science (NIHHS), Rural Development Administration (RDA), Korea. The crossing and in vitro embryo rescue was conducted between Lilium FA97-2 (L. ${\times}$ formolongi 'Silky White' ${\times}$ L. Asiatic 'Sunray') and L. Asiatic 'Bomi (Byeongga ${\times}$ Connecticut King)' by cut style pollination method (CSM) at Suwon in 2000. The first selection was done and was tentatively named as 'FA03-5' in 2003. After in vitro multiplication and bulbing production of 'FA03-5' line, growth and flowering characteristic tests were conducted from 2003 to 2005. The evaluation of characteristics and consumer preferences were surveyed at a lily flower show of NIHHS in 2005. 'Green Star' flowered in the middle of June and grew more than 120 cm stem in length. Flowers bloomed facing upward, unspotted in petals and greenish yellow (RHS, Y6D). 'Green Star' was male sterile. Year-round flowering can be done by storing the bulb under $-1.5^{\circ}C$ conditions. It was needed to control the Botrytis disease in wet season.

• 화훼연구
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• 제16권4호
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• pp.299-303
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• 2008

'Pacific Wave'는 농촌진흥청 국립원예특작과학원에서 2007년에 육성된 절화용 오리엔탈나리 품종이다. 수출용 상향개화성 오리엔탈나리 품종을 육성하기 위하여 1999년 백색의 'Simplon'과 분홍색의 'Spinoza'를 주두수분에 의해 교잡을 하여 획득한 교배실생 중에서 화색이 백색이고 상향개화성이며 향기가 강하고 화형이 안정된 'O-03-16' 계통을 2003년에 선발하였다. 이 계통의 특성검정은 조직배양에 의한 대량증식, 순화 및 양구를 거쳐 특정검정을 수행하였다. 2007년 '원교C1-92호'로 수원에서 3차 특성검정 및 계통 평가회의 기호성 조사를 통해 최종적으로 절화용 오리엔탈나리로 선발하여 'Pacific Wave'라 명명하였다. 'Pacific Wave'품종의 개화기는 2월부터 가온했을 때 6월 중순이었고, 꽃의 향기가 강하다. 화색은 백색에 황색(RHS, W155C + Y9A)심이 있고, 포장수송상 유리한 상향개화성이다. 식물의 초장은 115cm이고, 꽃의 크기는 20.1 cm이다. 꽃의 화피장은 12.2 cm, 화피폭은 4.2 cm이다. 엽장은 12.3 cm이고, 엽폭은 2.9cm 이다. 꽃에는 돌기반점이 있으며, 주두는 진한 회색이고 화분은 붉은 갈색이다. 구근의 크기는 19.6cm, 중량은 82.5 g이다. 구근 수확 후 -1 또는 $-2^{\circ}C$의 조건에서 동결저장을 하여 정식시기를 달리하면 주년개화가 가능하다. 엽소현상을 방지하기 위해서는 칼슘시비 및 대구의 외인편을 제거해 주는 것이 필요하고, 여름 장마시기에는 잎마름병 방제가 필요하다.

• 대한기계학회논문집B
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• 제40권5호
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• pp.339-345
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• 2016

본 연구에서는 천공과 유동 가이드를 활용한 방사형 히트싱크의 자연대류 열전달 향상에 관해 수치적으로 탐구하였다. 천공과 침니 기반의 유동 가이드를 활용한 개선된 형상의 방사형 히트싱크의 성능을 평가하고, 기존의 방사형 히트싱크와 열 성능을 비교하였다. 연구 결과, 천공형 히트싱크는 연구범위 내에서 천공의 개수와 직경이 클수록 열 성능이 좋아짐을 알 수 있었다. 침니 기반의 유동 가이드를 활용한 히트싱크에 대해서는, 핀의 개수, 침니와 바닥면 사이의 거리의 영향을 분석하였다. 그 결과 핀의 개수와 침니와 바닥면 사이의 거리에 최적화된 값이 있다는 것을 확인할 수 있었다. 또한 히트싱크의 방향이 상 방향($0^{\circ}$)에서 최고의 열 성능을, 측 방향($90^{\circ}$)일 때 최악의 열 성능이 나타나는 것을 알 수 있었다. 천공형 히트싱크와 최적의 구조를 갖는 유동 가이드를 갖는 히트싱크는 기존의 방사형 히트싱크와 비교하였을 때, 각각 최대 17%, 20% 개선된 열 성능을 가짐을 알 수 있었다. 본 논문은 공학과 관련한 획기적인 아이디어를 제시함으로써 창업기술개발, 벤처 및 기업가정신 함양에도 중요한 의미를 지닐 수 있다.

• Animal cells and systems
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• 제5권4호
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• pp.319-325
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• 2001

Transport of colored papers and decomposition of leaf litter of Quercus mongolica, Acer pseudo-sieboldianum, and Kalopanax pictus were investigated on three patches differentiated by aspect and understory in a temperate hardwood forest. Two patches are represented by dwarf bamboo (Patch SS) and herbaceous plants (Patch S), respectively, Iying on a south-west-facing slope. The other patch (Patch N) is located on a northeastfacing slope with herbaceous plants. Colored papers were placed on the patches to understand the pattern of litter movement on the ground. Papers were move dispersed in Patch S than in the other two patches. Some of the colored papers placed in Patch S moved upward. The results suggest that the litter movement is affected by aspect and that the leaf litter is retained by dwarf bamboo in Patch SS. Decay constant of Q. mongolica was significantly (p＜0.05) lower than those of K. pictus and A. pseudo-sieboldianum. Decay rates of Q. mongolica were significantly different between Patches N and S and between Patches SS and S (p＜0.05). On the other hand, decay rates of the other species were not significantly different among the three patches. The results suggest that aspect and understory exert an influence on redistribution and decomposition of leaf litter and that the effects could be different among the plant species.

• Geomechanics and Engineering
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• 제7권3호
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• pp.263-277
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• 2014

In the conventional design of retaining structures in a seismic zone, seismic inertia forces are commonly assumed to act upwards and towards the wall facing to cause a maximum active thrust or act upwards and towards the backfill to cause a minimum passive resistance. However, under certain circumstances this design approach might underestimate the dynamic active thrust or overestimate the dynamic passive resistance acting on a rigid retaining structure. In this study, a new analytical method for dynamic active and passive forces in c-${\phi}$ soils with an infinite slope was proposed based on the Rankine earth pressure theory and the Mohr-Coulomb yield criterion, to investigate the influence of seismic inertia force directions on the total active and passive forces. Four combinations of seismic acceleration with both vertical (upwards or downwards) and horizontal (towards the wall or backfill) directions, were considered. A series of dimensionless dynamic active and passive force charts were developed to evaluate the key influence factors, such as backfill inclination ${\beta}$, dimensionless cohesion $c/{\gamma}H$, friction angle ${\phi}$, horizontal and vertical seismic coefficients, $k _h$ and $k_v$. A comparative study shows that a combination of downward and towards-the-wall seismic inertia forces causes a maximum active thrust while a combination of upward and towards-the-wall seismic inertia forces causes a minimum passive resistance. This finding is recommended for use in the design of retaining structures in a seismic zone.

• Journal of Ecology and Environment
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• 제30권1호
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• pp.49-56
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• 2007

We placed and monitored 2,137 nest boxes to determine how the size of the entrance hole and the box placement influenced nest box selection by secondary cavity-nesting birds and to derive recommendations for the use of nest boxes for management of cavity-nesting birds in forested environments. A total of 566 pairs of seven bird species used the nest boxes from 1997 to 2006, 562 of which were secondary cavity-nesters. Sympatric tits such as varied tits (Parus varius), great tits (P. major), and marsh tits (P. palustris) were common breeding birds in nest boxes, and showed clear preferences for 4.0 cm, 3.5 cm and 3.0 cm nest holes, respectively. Tree sparrows (Passer montanus) and Eurasian nuthatches (Sitta europaea) preferred 4 cm and 3.5 cm holes, respectively. We did not detect selection for the directional orientation for the entrance hole, but the birds appeared to avoid nest boxes that faced steep or gentle upward slopes and those less than 1.8 m from the ground. These results are probably related to avoidance of disturbance and predation. We suggest that diverse species can be supported by the placement of nest boxes with entrance holes of various sizes and that specific species can be targeted by selecting the hole sizes preferred by those species. To attract secondary cavity-nesters, managers should avoid placing nest boxes close to the ground and facing hills. This study also suggests that careful selection and placement of nest boxes is needed to avoid biases in research using nest boxes.

• 한국환경농학회:학술대회논문집
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• 한국환경농학회 2009년도 정기총회 및 국제심포지엄
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• pp.228-239
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• 2009

The observations on climate change show a clear increase in the temperature of the Earth's surface and the oceans, a reduction in the land snow cover, and melting of the sea ice and glaciers. The effects of climate change are likely to include more variable weather, heat waves, increased mean temperature, rains, flooding and droughts. The threat of climate change and global warming on human and animal health is now recognized as a global issue. This presentation is described an overview of the latest scientific knowledge on the impact of climate change on zoonotic diseases. Climate strongly affects agriculture and livestock production and influences animal diseases, vectors and pathogens, and their habitat. Global warming are likely to change the temporal and geographical distribution of infectious diseases, including those that are vector-borne such as West Nile fever, Rift Valley fever, Japanese encephalitis, bluetongue, malaria and visceral leishmaniasis, and other diarrheal diseases. The distribution and prevalence of vector-borne diseases may be the most significant effect of climate change. The impact of climate change on the emergence and re-emergence of animal diseases has been confirmed by a majority of countries. Emerging zoonotic diseases are increasingly recognized as a global and regional issue with potential serious human health and economic impacts and their current upward trends are likely to continue. Coordinated international responses are therefore essential across veterinary and human health sectors, regions and countries to control and prevent emerging zoonoses. A new early warning and alert systems is developing and introducing for enhancing surveillance and response to zoonotic diseases. And international networks that include public health, research, medical and veterinary laboratories working with zoonotic pathogens should be established and strengthened. Facing this challenging future, the long-term strategies for zoonotic diseases that may be affected by climate change is need for better prevention and control measures in susceptible livestock, wildlife and vectors in Korea. In conclusion, strengthening global, regional and national early warning systems is extremely important, as are coordinated research programmes and subsequent prevention and control measures, and need for the global surveillance network essential for early detection of zoonotic diseases.

• 경영과정보연구
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• 제5권
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• pp.139-160
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• 2000

Todays our private universities have been facing with serious survival competition according to the opening of education market, the diminishment of college voluntarists and the increase of education supply. In coming the beginning of the year of 2000, though the equal formula. 'The fixed number of students of universities = The number of graduates of high schools' will he formed, even though the tendency of the fixed number of students of universities is maintained as it is, and it has been expected the unlimited competition would be unvaoidable, so private universities and private junior colleges which are weak in financial power are roaring the crisis consciousness that they may have to close doors before making every effort. Based on such presentation of problem as its study object, the range of study is limitted to the educational financial portion related to higher education field. Especially, the financial portion of private universities of higher educational field is discussed in priority. Besides, the present status of financial condition of our universities was portionally compared with that of in the advanced nations. It is true that pursuing the academic superiority of university education in our country, and attaining object of university as well as developing reflection in future should stand side by side. Therefore, payment of fee, supporting subsidy, etc. is attached too much importance to the financial problem. In our country, the financial allotment is attached too much importance to national universities. This is against the principle of equity to the tax payers, and equality of opportunity, so the level of supporting national funds should be upward formed and supported from 1.0% to higher than 20%. In conclusion, our private universities should adopt as many alternatives of rationalization of finance as possible, such as securing lots of funds and subsidies, and rationalized management of finance, and ensuring finance according to the increasing number of students after university specialization, etc.