• 생물환경조절학회지
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• 제27권4호
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• pp.381-390
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• 2018

본 실험은 기존의 플러그 육묘 시스템과 원통형 종이 포트 시스템을 상호비교하여 주요 과채류 육묘의 생육 특성을 검토 하기 위해 수행되었다. 초장, 엽면적, 경경, 생체중 등의 지상부 생육은 토마토, 오이, 수박 모두 원통형 종이포트와 플러그 트레이 간의 차이가 없었다. 총 근장은 토마토와 오이는 육묘초기, 수박은 전 기간동안 플러그 트레이가 원통형 종이포트에 비해 길었다. 뿌리의 직경별로 각 뿌리의 길이를 구분한 결과, 토마토는 시험구간 차이가 없었지만 오이와 수박은 모든 굵기의 뿌리에서 플러그가 종이포트에 비해 20~251% 길었다. 토마토 뿌리의 생체중은 육묘기는 플러그 트레이가 원통형 종이포트에 약 30% 무거웠지만 생육이 진전될수록 차이가 감소하였고, 정식 이후는 시험구간 차이가 없어졌다. 오이 뿌리의 생체중은 육묘기부터 정식 이후까지 플러그묘가 약 20~30% 무거웠고, 정식 이후 까지도 생육이 진전될수록 차이가 커지는 경향을 보였다. 수박은 육묘기부터 정식 7일후까지는 원통형 종이포트 묘의 지상부 생체중 및 건물중이 무거웠지만, 정식 7일 이후부터 역전되었다. 결론적으로 원통형 종이포트 묘와 플러그 트레이 묘의 지상부 생육은 전반적으로 차이가 없었고, 지하부 생육은 플러그묘의 생육량이 많았다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2583-2588
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• 2008

In the present experimental study, the regime limit and pressure drop of dry-plug flow (dry wall condition at the gas portions of plug flow) in round mini-channels has been investigated. The air-water mixture was flowed through the round mini-channels made of Teflon, where the tube diameters ranged from 1.26 to 2.06 mm. For the present experimental range, with decreasing of the tube diameter, the transition between the plug and slug flows (wet and dry) happened at the higher gas superficial velocity region, which were in good agreement with the previous flow pattern maps tested. On the other hand, the transition between the wet- and dry-plug flows was little affected by the change of the tube diameter. In the pressure drop of dry-plug flows, among the correlations tested, the Lee and Lee's (2008) correlation best fitted the measured pressure drop data within the mean deviation of 10% for the present experimental range.

• Restorative Dentistry and Endodontics
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• 제21권1호
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• pp.187-201
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• 1996

The purpose of this study was to evaluate the sealing ability of a calcium hydroxide plug treated with a bonding agent. Ninety extracted human anterior teeth and premolars with single canal were used in this study. Crowns were removed. the canal's were instrumented. and the roots were randomly divided into three groups of 30 each. In control group. a single apical seat was prepared with #60 K file 1mm short of the apex and the root canal was obturated with Gutta-percha and Sealapex by the lateral condensation method. In experimental group 1 and group 2. to prepare an apical isthmus of 1mm in length. the first apical seat was prepared with a #45 K file 1mm short of the anatomical apex and with a #60 K file 2mm short for the second apical seat. Dry calcium hydroxide powders were packed in the apical isthmus with a hand plugger and #60 K file and then. the root canal was obturated with Gutta-percha and Seal apex by the lateral condensation method. In experimental group 2. following an application of the bonding agent to the plug. the root canal was obturated in the same way. The teeth of each group were immersed in a 2% methylene blue dye solution. for 1, 2, and 4 weeks. The distance from the tip of the cone to the deepest penetration was measured using the Tool maker's microscope. The results were as follows : 1. The teeth having the calcium hydroxide plug treated with the dentin bonding agent (experimental group 2) showed the lowest leakage with 1.4705mm and the control group without apical plug(no apical isthmus) showed the highest leakage with 3.1735mm. 2. The control group without apical plug showed higher leakage than experimental group 1 having the calcium hydroxide plug treated without the dentin bonding agent(p>0.05). 3. The control group without apical plug and experimental group 1, having the calcium hydroxide plug treated without the dentin bonding agent. showed higher leakage than experimental group 2. having the calcium hydroxide plug treated with the dentin bonding agent(p<0.001). 4. The immersion time had no significant effect on the degree of leakage. In conclusion, the results showed that the calcium hydroxide plug treated with the dentin bonding agent could decrease the microleakage from the root apex effectively.

• Journal of Welding and Joining
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• 제17권2호
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• pp.29-35
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• 1999

This study was intended to use for the fatigue test in real structures and offer basic data for optimum welding structure design. To this purpose, we obserded the effect of the size and distance of plug welding hole on the static strength and fatigue life of welding structure under the shear/bending load for the improvement of fatigue life of plug welding joint between S/MBR and C/MBR in the lower structure of large bus. The result below is shown through this study. 1) Static and fatigue strength are strongly influenced by the direction of plug weld hole distributed. 2) Distances and diameters of the distributed holes are little dependent on the static strengths 3) In case of the directions of the distributed plug weld holes are vertical to the loading pin, fatigue life is dependent on distance of the distributed hole. 4) In case of the directions of the distributed plug weld holes are parallel to the loading pin, fatigue life is dependent on distance of the hole diameter.

• 한국작물학회지
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• 제46권2호
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• pp.121-124
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• 2001

Potato (Solanum tuberosum L.) tubers of 10, 20, 30, 40, and 50 g were planted in plug trays with vermiculite-based root medium on 10 August 2000 and grown for 15 days in a glasshouse to determine the effects of mini-tuber size on plug seedling growth and field performance of plug seedlings. For a control, common potato tubers weighing 50 g were also planted. As size of seed tubers planted increased from 10 to 50 g, seedling height decreased from 24.6 to 20.0cm while shoot number per seedling increased from 2.0 to 3.5, main stem diameter from 4.3 to 6.1mm, and fresh weight of root + top from 9.3 to 19.4 g/seedling. At 90 days after transplanting plug seedlings, the total number of tubers per plant increased from 3.62 to 4.72, average tuber weight from 62.9 to 72.8g, and total tuber yield 20.5 to 23.6 t/ha with increase in seed tuber size. Plug seedlings raised from 50g tubers produced 22% more tubers per plant and had 21 % higher＞80g tuber yield than the directly planted potatoes.

• 대한기계학회논문집B
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• 제28권10호
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• pp.1163-1171
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• 2004

The variation of spark plug location have one of the effects on combustion characteristics. Several parameters of the effect on combustion characteristics are shape of combustion chamber, the spark plug position, turbulence flow and so on. This paper presents an experimental study according to variation of spark plug protrusion and PDA valve which have effects on characteristics of combustion and emission in single cylinder gasoline engine. Also, this paper emphasized that combustion stabilization was making by way of the reinforcement of the turbulent flow with the PDA valve. A feasibility and necessity of combustion pressure based cylinder spark timing control according to spark plug protrusion has been examined. So, this was obtained COV$\_$imep/ and the mass fraction burned(MFB) and the specific fuel consumption(sfc). Using the results of the test, the effects of the variable spark plug location and PDA valve can be improved fuel consumption and be available for the combustion stability.

• 현장농수산연구지
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• 제12권1호
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• pp.39-45
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• 2010

본 연구는 Dianthus spp와 Coreopsis spp의 삽목시기와 용토, Plug 규격이 생육 및 발근 상태에 미치는 영향을 구명하고자 실시하였다. Dianthus spp와 Coreopsis spp 두 품종 모두 삽목 시기가 늦어질 수록 발근율과 발근 수가 낮아졌다. 5월 20일에서 8월20일 삽목 처리구에서는 두 품종 모두 90% 이상 발근하였으나 9월 20일 삽목한 처리구에서는 Dianthus spp와 Coreopsis spp 두 품종이 각각 87%와 82%의 저조한 발근율을 보였고 발근 수 역시 9월 20일 처리구가 가장 저조하였다. 또한 Dianthus spp와 Coreopsis spp 두 품종 모두 모래를 제외한 모든 용토에서 90%이상 발근되었고 peatmoss(1)+perlite(1) 혼합용토에서 발근수가 가장 많았다. Coreopsis spp는 plug 162공에서 발근율이 98%로 가장 높았고 Dianthus spp는 162공과 200공에서 각각 발근율이 95.8%와 96%로 높고 근권부 형성율이 좋았다.

• 전력전자학회논문지
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• 제26권4호
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• pp.294-297
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• 2021

A grid voltage estimation method for modular plug-in active power decoupling (APD) circuits is proposed in this study as direct replacements of electrolytic capacitors. Since modular plug-in APD circuits cannot have additional grid voltage sensors and should be operated independently without information exchange with the front-end converter, it is impossible to obtain the phase information of the grid directly. Therefore, the proposed method uses the second-order harmonic component of the DC-link voltage to estimate the grid voltage necessary to control the APD circuit. By employing the proposed method, the concept of modular plug-in APD circuits can be realized and implemented without direct detection of the grid voltage. The experimental results based on hardware-in-the-loop simulation (HILS) validate the effectiveness of the proposed control method.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1585-1589
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• 2007

The HANARO, a 30 MW multi-purpose research reactor in Korea, will be equipped with a neutron guide system, in order to transport cold neutrons from the neutron source to the neutron scattering instruments in the neutron guide hall near the reactor building. The neutron guide system of HANARO consists of the in-pile plug assembly with in-pile guides, the primary shutter with in-shutter guides, the neutron guides in the guide shielding room with dedicated secondary shutters, and the neutron guides connected to the instruments in the neutron guide hall. The functions of the in-pile plug assembly are to shield the reactor environment from a nuclear radiation and to support the neutron guides and maintain them precisely oriented. The primary shutter is a mechanical device to be installed just after the in-pile plug assembly, which stops neutron flux on demand. This paper describes the mechanical design of the in-pile plug assembly and the primary shutter for the neutron guide system at HANARO. The design of the guide shielding assembly for the primary shutter and the neutron guides is also presented.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.1882-1887
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• 2007

In the present experimental study, the effect of interfacial tensions on pressure drop of air-water two-phase flow in round mini-channels was investigated. A glass (highly wettable) tube and a Teflon (poorly wettable) tube, both in 350 mm length but 1.8 mm and 1.59 mm in inner diameters each, were used for the tests. All the experiments were performed only in the plug flow regime, confirmed by visualization. In the glass tube, the gas plugs were surrounded by the liquid film along the inner periphery. On the other hand, the inner wall remained dry at the gas portion in the Teflon tube. The pressure drop of the plug flow in the Teflon tube without the liquid film) appeared much larger than in the glass tube (with the liquid film) due to dissipation of energy by movement of the wetting lines. In this paper, various correlations on the two-phase pressure drop of plug flows were compared and a modified correlation was proposed, taking account of the surface wettability.