• International Journal of Railway
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• 제5권4호
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• pp.163-166
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• 2012

Many different types of floating slab track have been developed and installed around the world to reduce vibrations and noise originating in the surrounding environment. The main objective of this study is to examine the influence of slab length on behavior of floating slab track based on rail-slab-isolator interaction. The floating slab track is modeled by the connection between rail, slab, isolator, and slab mat in the transition zone. All elements were assembled in a simplified two-dimensional (2D) finite element model (FEM). The maximum length of FST is then investigated based on the maximum additional rail stress criterion as described in UIC 774-3R since no fully accepted design criteria for the slab length in FST systems currently exist.

• 수산해양교육연구
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• 제23권4호
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• pp.642-647
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• 2011

In order to analyze the influence of floating marine debris (FMD) in the East China Sea (ECS), a sighting survey was conducted from July 1st to July 14th, 2009 navigating about 966 km using a training vessel "Kaya (1,737 ton)" of Pukyong National University. The sampled zones are divided into 5 transect by observation day during the survey days and again specified with 45 segments per unit hour on the survey routes. The results of distribution of FMD are as follows: 1. The quantities of FMD at the central China Sea(CE) and northern part of Taiwan(NT) were found as total mean of 90.8 ea/hr, 56.7 ea/hr, respectively, and also 36.8 ea/hr, western part of Kyushu district(WJ), 10.7 ea/hr, 8.0 ea/hr, western(OK1) and northern part(OK2) of Okinawa, respectively. 2. Temporal variation of FMD is represented by depicting the sinusoidal curve as shape as tide in CE and OK1. 3. The higher sea surface temperature (SST) is as likely as if Kuroshio current exists strongly, the less quantities are decreased. On the other hand, the coastal zone of ECS and near of Yellow Sea are increased by lower SST.

• 한국결정성장학회지
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• 제9권6호
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• pp.547-552
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• 1999

Langasite$(La_{3}Ga_{5}SiO_{14})$ single crystal was successfully grown by Floating Zone (FZ) method and characterized. The growth rate was 1.5 mm/h and the rotation speed was 15 rpm for an upper rotation and 13 rpm for a lower rotation. The grown crystal was 12 mm in length and 6 mm in diameter. The grown crystal was dark orange color and it was grown along [001] direction. The composition of grown crystal and the structure were analyzed using XRD and WDS. The electrical properties of grown crystal at various frequencies and temperatures were discussed.

• 한국결정성장학회지
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• 제18권4호
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• pp.137-139
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• 2008

Floating zone, neutron transmutation-doped and magnetic Czochralski silicon crystals are being widely used for fabrication power devices. To improve the quality of these devices and to decrease their production cost, it is necessary to use large-diameter wafers with high and uniform resistivity. Recent developments in the crystal growth technology of Czochralski silicon have enable to produce Czochralski silicon wafers with sufficient resistivity and with well-controlled, suitable concentration of oxygen. In addition, using Czoehralski silicon for substrate materials may offer economical benefits, First, Czoehralski silicon wafers might be cheaper than standard floating zone silicon wafers, Second, Czoehralski wafers are available up to diameter of 300 mm. Thus, very large area devices could be manufactured, which would entail significant saving in the costs, In this work, the conventional Czochralski silicon crystals were grown with higher oxygen concentrations using high pure polysilicon crystals. The silicon wafers were annealed by several steps in order to obtain saturated oxygen precipitation. In those wafers high resistivity over $5,000{\Omega}$ cm is kept even after thermal donor formation annealing.

• 한국결정학회지
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• 제11권4호
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• pp.231-237
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• 2000

CMR Materials RE/sub 1-x/Ca/sub x/MnO₃(RE=La, Nd, A=Ca, Sr) were grown using the floating zone image furnace with halogen lamps as heat source. The growth condition was at 2∼10 mm/hr growth rate in air atmosphere, were 445∼50 rpm and 20∼25 rpm of rotation rate of feedrod and growing crystal, respectively. The grown crystals showed shiny black color and annealed at 1500℃ in a box furnace to release the residual stress during cooling. Characterization analyses of the crystal were carried out using XRD and SEM. The crystal structure of Nd/sub 0.7/Ca/sub 0.3/MnO₃ was analyzed with smart CCD XRD was lattice parameter of a=5.425(4)Å, b=5.434(4)Å, and c=7.712(5)Å, an orthorombic system with space group of pbnm.

• 열처리공학회지
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• 제28권2호
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• pp.82-86
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• 2015

In this study, the temperature gradient of a floating zone (FZ) apparatus, which is very difficult to directly measure, could be estimated by using the relationships between the lamellar spacing of directionally solidified TiAl alloys and the solidification rate, It was found that the calculated temperature gradient of the FZ apparatus was much higher, and almost ten times higher than that of a Bridgman type directional solidification apparatus.

• 한국결정학회지
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• 제11권3호
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• pp.151-156
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• 2000

Yb/YAG single crystals were grown from the melt composition of Y/sub 1-x/Yb/sub x/)₃Al/sub 5/O/sub 12/ where x equal to 5, 10, 15, 20, 25, 33, 50, 75 and 100 at % by floating zone method. Optimum growth parameters to get high quality single crystals were 3.5 mm/h of growth rate and 20 rpm of rotation rate under the N₂ atmosphere. After the growth, color of crystals was appeared with pale blue due to the lack of oxygen, but it was disappeared after annealing at 1450℃ for 2 hr. Absorption coefficients were linearly increased depending on the concentration of Yb/sup 3+/ ions. Broad emission band was measured in the range of 1020 to 1050 nm with the peak intensity at 1031 nm and 1051 nm because of ²F/sub 5/2/(1)→²F/sub 7/2/(3) and ²F/sub 5/2/(1)→²F/sub 7/2/(4) transition respectively. When Yb/sup 3+/ ions were substituted with high rates, there were tendency to decrease the measured fluorescent lifetime for Yb ions depending on the concentration of Yb/sup 3+/ ions.

• 한국항해항만학회지
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• 제36권6호
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• pp.449-458
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• 2012

최근 해상을 비롯한 수상공간에 다양한 플로팅 건축물이 계획되거나 설치되고 있다. 그러나 관련 법제도의 미비로 인하여 플로팅 건축물의 설계 및 건설 혹은 관리운영에서 많은 문제점이 발생되고 있으며 이는 플로팅 건축물의 활성화를 저해하는 중요한 요인이 되고 있다. 따라서 본 연구에서는 플로팅 건축물에 대한 국내 법제도 적용 사례 및 해외 관련 법제도 사례 조사를 실시하여 우리나라에서 플로팅 건축물의 법제도 개선을 위한 기초자료와 개선방향을 제시하였다. 연구결과 플로팅 건축물은 선박이 아닌 건물로서 법적 지위를 확보하며 플로팅 건축물 설치 특별구역을 설정하여 건물의 대지를 조성하고 별도 기술기준을 적용하며 건축인허가 및 등기 절차를 활용할 수 있도록 법제도 개선이 필요하다.

• 한국물환경학회지
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• 제32권2호
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• pp.205-215
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• 2016

In order to improve water quality in the Paldang Lake, a riparian vegetation belt, treatment wetland, and artificial floating island were designed for introduction in the upland field, the estuary of tributaries, and the section of water facing mountainous land, respectively. We synthesized vegetation information collected from a reference river and found that herbaceous, shrubby, and tree vegetation zones tended to be dominated by Phragmites japonica, Phalaris arundinacea, etc.; Salix gracilistyla, S. integra, etc.; and S. koreensis, S. subfragilis, and Morus alba, respectively. In our plan, the herbaceous vegetation zone, which is established on floodplains with a high frequency of disturbance, will be left in its natural state. A shrubby vegetation zone will be created by imitating the species composition of the reference river in the ecotone between floodplain and embankment. A tree vegetation zone will be created by imitating species composition on the embankment slope. In the treatment wetland, we plan to create emerged and softwood plant zones by imitating the species composition of the Zizania latifolia community, the Typha orientalis community, the P. communis community, the S. integra community, and the S. koreensis community. The floating island will be created by restoring Z. latifolia and T. orientalis for water purification purposes.

• 한국결정성장학회지
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• 제2권1호
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• pp.10-19
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• 1992

Soft Ferrites 가운데 대표적인 자성재료로써 최근에 개발된 Mn-Zn Ferrite는 높은 초기투자율과 포화자속밀도, 낮은 손실계수를 갖고 있으며 또한, 단결정으로써의 기계적 특성이 우수하며 VTR Head의 소재로 사용되는 중요한 전자부품이다. melt를 수용하는 도가니를 사용치 않아 결정으로의 불순물 침입이 없으며 halogen lamp로부터 방출된 적외선을 열원으로 하여 한 곳에 초점을 이루어 온도구배를 크게 유지하여 결정성장을 이루는 Floating Zone(FZ)법에 의해 Ar 및 $O_2$혼합가스 분위기 하에서 직경 8mm의 Mn-Zn Ferrite 단결정을 육성하였다. 성장 중 용융대에서의 최고온도는 $1650^{\circ}C$ 온도를 유지하였고 결정성장 속도는 10mm/hr, 회전속도는 20 rpm 이었으며 성장방위를 확인하기 위해 Laue 분석 및 XRD, TEM을 이용, 결정의 상등을 분석하였으며 화학적인 etching을 하여 광학현미경을 통해 etch pits 형상을 관찰하였다. 그리고 양질의 결정을 얻기 위해 원료봉 직경에 따른 결정화 속도와 적정한 melt직경과 길이에 대한 상관관계를 찾아내었고 또한 성장계면의 양상에 대해 고찰하였다.