• Journal of Magnetics
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• 제12권2호
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• pp.53-58
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• 2007

Theory of the generation linewidth of a current-driven spin-torque magnetic nano-oscillator in the presence of thermal fluctuations has been developed and a simple analytical formula for the generation linewidth in the supercritical regime of generation has been derived. It is shown that the strong dependence of the oscillator frequency on the precession power leads to substantial broadening of the generation linewidth of a spin-torque oscillator compared to the case of a linear oscillator, i.e. an oscillator with power-independent generation frequency. The relation between the nonlinearity-induced broadening of the generation linewidth and the nonlinearity-induced increase of the phase-locking band of a spin-torque oscillator to an external microwave signal has been revealed. The derived expression for the generation linewidth predicts a linewidth minimum when the nano-contact is magnetized at a certain angle to its plane, at which the nonlinear frequency shift vanishes. This result is in good agreement with recent experiments.

• Nuclear Engineering and Technology
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• 제53권11호
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• pp.3643-3652
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• 2021

Sizing the tube inlet orifice of a Once-Through Steam Generator (OTSG) is important to protect the integrity of the tubes from thermal cycling and vibration wear. In this study, a new sizing criterion is proposed for the tube inlet orifice to suppress the parallel channel instability in an OTSG. A perturbation method is used to capture the essential parts of the thermal-hydraulic phenomena of the parallel channel instability. The perturbation model of the heat transfer regime boundaries is identified as a missing part in existing models for sizing the OTSG tube inlet orifice. Limitations and deficiency of the existing models are identified and the reasons for the limitations are explained. The newly proposed model can be utilized to size the tube inlet orifice to suppress the parallel channel instability without excessive engineering margin.

• Nuclear Engineering and Technology
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• 제53권8호
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• pp.2464-2476
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• 2021

Direct-contact heat transfer of a single saturated droplet upon colliding with a heated wall in the regime of film boiling was experimentally investigated using high-resolution infrared thermometry technique. This technique provides transient local wall heat flux distributions during the entire collision period. In addition, various physical parameters relevant to the mechanistic modelling of these phenomena can be measured. The obtained results show that when single droplets dynamically collide with a heated surface during film boiling above the Leidenfrost point temperature, typically determined by droplet collision dynamics without considering thermal interactions, small spots of high heat flux due to localized wetting during the collision appear as increasing We_n. A systematic comparison revealed that existing theoretical models do not consider these observed physical phenomena and have lacks in accurately predicting the amount of direct-contact heat transfer. The necessity of developing an improved model to account for the effects of local wetting during the direct-contact heat transfer process is emphasized.

• 한국경제지리학회지
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• 제3권1호
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• pp.53-81
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• 2000

1980년대에서 1997년 사이에 한국 섬유 의류산업은 국내 가격경쟁력을 기반으로 한 수출주도형 성장체제에서 생산력의 지리적 확장을 가져오는 해외생산 그리고 고급의류 내수시장의 증가로 따른 기술 발달과 자동화에 기반을 둔 질적 성장체제로 전환하였다. 이러한 재구조화는 1987년 노동자 대투쟁으로 인한 임금의 급상승으로 1986년까지 진행된 수출주도형 성장체제에 위기가 왔다는데 일차적 원인을 둘수 있다. 특히 임금상승과 노동의 세력화에 따른 단체교섭의 형성은 장시간 노동시간과 저임금 구조에 기반을 둔 대량 생산과 대량수출의 결합체제에 위기를 가져왔다. 따라서 본 논문의 목적은 1980년과 1997년 사이에 발생한 한국 섬유 의류산업의 발전모델 또는 양식의 전환을 밝히고자 하는 것이다. 이를 위해 본 논문은 역사적 맥락에서 1987년 이전과 이후의 축적체제의 변화와 함께 조절양식의 제도적 형태인 임고용 관계, 기업간 관계 그리고 국가와 기업관계의 변화를 살펴보았다.

• Asian Pacific Journal of Cancer Prevention
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• 제17권3호
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• pp.1255-1259
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• 2016

Background: Oral physiotherapy or mouth exercise is considered to be an adjunct but mandatory treatment modality for oral submucous fibrosis (OSMF). This study planned to evaluate the clinical efficacy of a newly designed mouth exercising device (MED) in OSMF patients receiving local ointment, intra-lesional drugs and surgical treatment. Materials and Methods: A total of 231 OSMF patients were selected and treated with basic regime including topical corticosteroids, oral antioxidants and the icecream-stick exercise regime and allotted randomly to two equal groups A and B. Group-A patients were additionally given MED. Subgroups A1 and B1 patients with an inter-incisal distance (IID) 20-35mm were not given any additional therapy; subgroup A2 and B2 patients (IID 20-35mm) were treated additionally with intra-lesional injections. Subgroups A3 and B3 with IID<20mm were managed surgically. IID was measured at baseline and at 6 months recall. The change in IID measurements was calculated and statistically analyzed using 2-way ANOVA and Tukeys multiple post hoc analysis. Results: Average improvement in IID after six months of recall visits was observed to be 8.4 mm in subgroup-A1 (n-53) compared to 5.5 mm in B1(n-50) (p<0.01). The IID improvement in subgroup-A2 was found to be 9.3mm (n-46) compared to 5.1 mm in B2 (n-48) (p<0.01). In the surgery group, mouth opening improvement was observed to be 9.6 mm in subgroup A3 (n-18) compared to 4.8 mm for B3 (n-16) (p<0.01). Conclusions: Use of the MED appears to be effective for increasing oral opening in OMSF patients in conjunction with local, injection and/or surgical treatment.

• 한국수산과학회지
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• 제53권4호
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• pp.506-514
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• 2020

We investigated seed management and feeding regime of larval red spotted grouper Epinephelus akaara using live food organisms. Fertilized eggs were produced in March 2020 by manipulating photoperiod and water temperature. Broodstock (F0) produced approximately 0.30×10⁶ eggs, of which 0.25×10⁶ were fertilized; first-generation broodstock (F1) produced 2.00×10⁶ eggs, of which 1.90×10⁶ were fertilized. Larvae were reared at temperatures of 21.0-24.5℃. The feeding regime consisted of rotifers Artemia, and commercial pellet feed. From 5-8 days after hatching (dah), rotifers collected from high-density incubation tanks were fed to grouper larvae at a density of 10-20 individuals/mL. From 9-30 dah, rotifers collected from low-density incubation tanks were fed to larvae at a density of 10-20 individuals/mL. Newly hatched Artemia were provided from 20-24 dah and enriched Artemia from 25-50 dah. Commercial pellet feed was given starting at 13 dah. The average mouth size in hatchlings was 263.4±3.7 ㎛ at 5 dah, 406.7±21.0 ㎛ at 11 dah, and 856.9±136.6 ㎛ at 21 dah. At 1 dah, larvae had a mean total length of 1.95±0.06 mm. At 66 dah, the mean TL was 4.0 cm. The final number of surviving red spotted grouper larvae was 218,380 fishes.

• 생태와환경
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• 제53권4호
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• pp.390-407
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• 2020

This study was carried out to evaluate the restoration effect in the restored Yangjae stream and to draw up an adaptive management plan based on the results. As the result of evaluation on the restoration effect, the restored Yangjae stream was evaluated with low naturalness in both terms of the morphology of the stream and the composition and spatial distribution of vegetation. The diverse functional groups were introduced in the vegetation restoration, but the flooding regime, which is significant in the spatial distribution of riparian vegetation, were not correctly reflected. Exotic species or species that were not ecologically suitable for the location were introduced on the embankment and thus a measure to improve those problems is required. As the ecological principle was not reflected in the restoration plan, the stream was constructed as the double terrace structure. Therefore, the width of the waterway was narrowed further, and the waterfront was not designed to accommodate changes from flooding disturbance, making the micro-topography of the stream simpler and the naturalness lower. The adaptive management plan was prepared to improve those problems, and a plan for creating an ecological network was recommended to enhance the restoration effect.

• 무역상무연구
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• 제53권
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• pp.101-133
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• 2012

The paper aims to analyse the obligations and Responsibilities of shipper in the Rotterdam Rules. The Rotterdam Rules, has underlying intention that it will provide uniform law for the international carriage of goods by sea. It is highly expected that the Rotterdam Rules will create the new international legal regime replacing Hague-Visby Rules and Hamburg Rules. Rotterdam Rules provide the obligations and responsibilities of shipper in express. The shippers obliged to provide, (a) duty as to the condition in which the cargo has to be delivered to the carrier, (b) cooperation of the shipper and the carrier in providing information and instruction, and (c) shipper's obligation to provide information, instructions and documents. The shipper is liable for loss or damage sustained by the carrier if the carrier proves that such loss or damages was caused by a breach of the shipper's obligations. However, the shipper is relieved of all or part of its liability if the cause or one of the causes of the loss or damage is not attributable to its fault or to the fault. But, the shipper shall indemnify the carrier against loss or damage resulting from the inaccuracy of such information. Rotterdam Rules is providing rather concrete as to the shipper's responsibilities and burden of proof in separate chapter. The question is whether such burden of proof of the fault should be imposed to the shipper.

• Nuclear Engineering and Technology
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• 제53권10호
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• pp.3229-3235
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• 2021

The key process used in nuclear industries for the management of radiotoxicity associated with spent fuel in a closed fuel cycle is solvent extraction. An understanding of hydrodynamics and mass transfer is of primary importance for the design of mass transfer equipment used in solvent extraction processes. Understanding the interfacial phenomenon and the associated hydrodynamics of the liquid drops is essential for model-based design of mass transfer devices. In this work, the phenomenon of drop formation at the tip of a nozzle submerged in quiescent immiscible liquid phase is revisited. Previously reported force balance based models and empirical correlations are analyzed. Experiments are carried out to capture the process of drop formation using high-speed imaging technique. The images are digitally processed to measure the average drop diameter. A correlation based on the force balance model is proposed to estimate drop diameter and jet length. The average drop diameter obtained from the proposed model is in good agreement with experimental data with an average error of 6.3%. The developed model is applicable in both the necking as well as jetting regime and is validated for liquid-liquid systems having low, moderate and high interfacial tension.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2016년도 학술발표회
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• pp.296-296
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• 2016

한강유역의 다목적댐인 소양강댐, 충주댐, 횡성댐의 운영이 하류부에 미치는 조절효과를 분석하기 위해 3개의 다목적댐이 모두 운영되고 있는 현재의 유역상황과 소양강댐, 충주댐, 횡성댐이 각각 없을 경우를 가정하여 시나리오별로 팔당댐 지점에서 유황곡선 차이를 검토함으로써, 3개 다목적댐의 조절효과를 정량적으로 분석하였다. 각 시나리오별 유출분석시 소양강댐, 충주댐, 횡성댐의 운영이 이루어질 경우에는 각 댐의 방류량 자료가 모형에 고려되도록 하였으며, 반대로 댐 운영이 이루어지지 않을 경우에는 각 댐의 유입량 자료가 모형에 반영되도록 하였다. 또한, 북한강 본류구간에 위치한 의암댐과 청평댐에 대해서는 발전용댐이기 때문에 유입량이 모두 방류되는 것으로 가정하여 적용하였다. 분석기간은 횡성댐의 자료 기간을 고려하여 2001~2009년을 선정하였으며, 시나리오별 각 댐의 조절효과를 정량화하기 위해 하류부인 팔당댐 지점에서의 유황곡선 차이를 계산하여 비교하는 방법을 이용하였다. 소양강댐 운영에 따른 팔당댐 지점에서의 조절유량은 약 10.3억$m^3$이며 조절기간은 304일로 분석되었고, 충주댐 운영에 따른 조절유량은 약 11.9억$m^3$에 조절기간은 336일, 횡성댐 운영에 따른 조절유량은 약 0.53억$m^3$에 조절기간은 303일로 분석되었다. 3개 다목적댐이 모두 운영될 경우의 유황 조절효과는 약 22.5억$m^3$에 333일로 분석되었다.