• 정보저장시스템학회논문집
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• 제8권1호
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• pp.16-21
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• 2012

SAW device is widely used as filters, sensors, actuators in various technologies. And capacitive sensor is tremendously used to measure pressure, gap, etc. The application of SAW device as signal conditioner of capacitive sensor reduces noise level and enables high precision measurement. The response increase of SAW based capacitive sensor is produced just before the two capacitive electrode contacts by the existence of parasitic resistance of capacitive electrode. In this paper, we analyze the effects of parasitic resistance and propose the calibrating method using lumped component and execute the high precision gap measurement using calibrated system. And xx nm resolution and yy ${\mu}m$ stroke was attained.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 B
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• pp.706-712
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• 1998

Previous counter-current flow limitation (CCFL) and critical heat flux (CHF) studies included investigations on the inlet entrance, inclined channel and gap effects for the most part. In this study, the local CHF correlation was presented to be used in the numerical analysis for the 3 dimensional hemispherical geometry. Also, first-principle analyses were performed to determine the maximum heat removal capability from the debris through the gap that may be formed during a core melt accident. The maximum heat removal capability by gap cooling can be applied in quantitatively assessing the severe accident management measures.

• 한국전기전자재료학회논문지
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• 제22권1호
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• pp.93-97
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• 2009

We analyzed voltage characteristics of toner particle type display according to particle layers and cell gap between two electrodes and ascertained the aging effects by measuring the response time of particles with and without aging process. The threshold/driving/breakdown voltage is proportional to layers of toner particles and cell gap and the response time at driving voltage is faster than that of threshold and breakdown voltage because of different q/m of color and black particles. The analysis of response time is a method of estimation of optical characteristics, driving voltage and particle lumping and these results are promoted by aging process. We use the laser and photodiode to measure response time and optical properties. It has not been studied and reported to analyze the relationship of response time, threshold/driving/breakdown voltage, lumping phenomena, cell gap, and aging process for toner particle type display.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부A
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• pp.386-392
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• 1998

Previous counter-current flow limitation (CCFL) and critical heat flux (CHF) studies included investigations on the inlet entrance, inclined channel and gap effects for the most part. In this study, the local CHF correlation was presented to be used in the numerical analysis for the 3 dimensional hemispherical geometry. Also, first-principle analyses were performed to determine the Maximum heat removal capability from the debris through the gap that may be formed during a core melt accident. The maximum heat removal capability by gap cooling can be applied in quantitatively assessing the severe accident management measures.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.316-320
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• 2008

A light rail transit, using a linear induction motor, is generally composed with reaction plates along railroad track and the three phase primary on the vehicle. This linear induction motor is driven to keep clearance between the primary and the secondary of the ground for preventing any contact. Therefore efficiency and power factor is very low. In addition, the reaction plate installed on the ground throughout entire railway is impossible to keep uniform gap and it may cause system deterioration. In this paper, A rotary-type small-scale model of a linear induction motor for various characteristic analysis is designed. Thrust force, normal force and input current of the model by air-gap variation have been analyzed by using a Finite Element Method (FEM). The effects of air-gap variation on system performance have been considered by analysis results.

• Nuclear Engineering and Technology
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• 제34권2호
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• pp.165-175
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• 2002

Effects of gap sizes (3.9-44.3 mm) of vertical annuli on nucleate pool boiling heat transfer of water at atmospheric pressure have been obtained experimentally. Through the study, tubes of the closed bottom have been investigated and results are compared with those of a single unconfined tube. According to the results, the annular condition gives much increase in heat transfer coefficient at moderate heat fluxes. The increase is much enhanced 3s the gap size decreases. At the same tube wall superheat (about 3.1 K) the heat transfer coefficient for the least gap size (i.e., 3.9 mm) is more than three times greater than that of the unconfined tube. However, deterioration of heat transfer occurs at high heat flux for confined boiling.

• 마케팅과학연구
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• 제19권4호
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• pp.1-10
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• 2009

本研究的目的是对咖啡店的 "重要性"（顾客在光顾咖啡店以前的感知）和积极或消极的 "满意度"（顾客在光顾咖啡店以后的感受）之间的差距进行分类, 并分析这些差距对对购买行为的影响. 为此, 我使用重要性和满意度之间的差距作为选择咖啡店的解释变量, 并通过使用有序Probit模型（OPM）来实证分析差距对购买行为（整体满意度和愿意到再次光顾）的影响方向和大小. 先前使用IPA的研究评估了差距影响的方向和大小的象限, 但是在分析差距对顾客的影响方面却失败了. 在本研究中, 我评估了积极和消极的差距对顾客满意度和愿意去再光顾的影响. 通过使用OPM,我量化了积极和消极的差距对顾客整体满意度和愿意去再光顾的影响. 每个人的支出, 光顾的频率和购买咖啡的地方对顾客整体满意度有最积极的影响. 光顾的频率, 在每人的支出之后, 然后是购买咖啡的地方对顾客整体满意度有最积极的影响. 因此每个人的支出和光顾的频率对顾客整体满意度有最积极的影响. 这一发现意味着一个在咖啡店每次或每周花费5000韩元的顾客的实际的满意度越高（差距), 其整体满意度和愿意去再光顾就越高. 虽然经济效益对总体满意度和愿意去再光顾有显著影响, 但是大专和大学的学生仍然愿意去咖啡馆并愿意消费5000韩元, 因为他们不只是购买咖啡本身而且将咖啡店作为其他活动的场所, 例如工作, 和朋友见面或是放松的地方. 学院和大学的学生还可以在咖啡店通过个人电脑上网, 看电影, 学习, 因此, 咖啡馆应对顾客提供适当的设施和服务. 咖啡店品牌的积极差距对愿意去再光顾有积极的影响表明顾客满意度越高, 顾客越愿意去再光顾. 另一方面, 这一因素的消极差距意味着顾客满意度越低, 顾客再光顾的意愿也越低. 因此, 在本研究中, 与其他评估的因素相比, 品牌因素对满意度有较大的影响. 鉴于国内咖啡文化变得越来越高级, 大专院校的学生对这一趋势也很敏感, 所以学生有很多可选择的品牌. 在韩国最高级的咖啡店, 外墙是玻璃建造的并可以打开, 内部是充满异国情调的开放式厨房. 这些高级咖啡店作为标志的功能复合大专院校学生的品味. 韩国咖啡店已成为一个文化品牌. 从品牌因素来看, 为了让顾客觉得这些咖啡店是高级的, 高质量的设备和提供更好服务的措施应当建立起来. 韩国咖啡馆作为蓬勃发展的行业品牌竞争加剧的结果表明, 提供与竞争对手不同的额外服务是有必要的. 顾客可以免费使用扫描仪. 另一个可以用来提高品牌的战略是提供和经营为集体学习而准备的讨论会议室. 如果咖啡馆采取这些类型的策略, 学院/大学的学生将更有可能认为他们承担的费用是值得的, 随后, 他们将可能更满足这些咖啡馆的品牌, 并更愿意再次光顾. 性别和学习年数对总体满意度和再光顾的意愿有最消极的营销. 女学生比男学生更容易满足和再光顾. 三, 四年级的学生比一, 二年级的学生更容易满足和再光顾. 喝咖啡的学生, 单独在咖啡店看书, 用笔记本电脑是很容易被注意到的. 高年级学生为了有效地利用时间用于自我发展和寻找工作往往独自光顾咖啡店. 从积极的差距来看, 经济效率这一因素对总体满意度和愿意再光顾有最大的影响. 与咖啡价格一起, 学生实际满意度（差距）越高, 总体满意度和再光顾的意愿也越高. 有消极差距的经济效率队再光顾有消极营销的结果表明较小的消极差距可以让再光顾的意愿更高. 在持续恶化的市场环境中, 坐落在大专院校附近的咖啡店采取诸如积分或会员卡, 和信用卡 公司的战略联盟, 发展套餐菜单或季节菜单和免费咖啡服务这些战略来提高竞争力. 就消极差距而言产品功率也有消极的影响, 这表明较高的负差距会导致较低的再光顾的意愿. 因为还有更多的客户比前几十年, 在这十年里更喜欢咖啡, 新一代的客户, 即学院/大学的学生, 希望除了咖啡还有更重菜单项目. 因此, 咖啡店应当增加配菜项目, 如华夫饼, 糕, 蛋糕, 三明治和沙拉. 例如, 星巴克韩国正在努力加强卖草莓糕, 艾草香味, 南瓜产品, 并提供免费的咖啡或奶油. 总而言之, 咖啡馆应注重提高其经济效率, 品牌和产品功率, 以加强大专院校学生的满意度. 由于店铺毗邻学大专院校可享受地缘优势, 就经济效率, 品牌和产品功率而言提供不同的服务, 很可能会提高客户满意度和回访. 咖啡厅的品牌, 因此, 应不断创新和变化, 以满足顾客的愿望. 由于这项研究只是针对在首尔的大专院校的学生, 需要针对不同地区和年龄组的比较研究来概括本研究的结果和建议.

• Wind and Structures
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• 제30권4호
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• pp.367-378
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• 2020

Two-dimensional Delayed Detached Eddy Simulation (DDES) was carried out to investigate the uniform flow over a twin-box bridge deck (TBBD) with various gap ratios of L/C=5.1%, 12.8%, 25.6%, 38.5%, 73.3% and 108.2% (L: the gap-width between two girders, C: the chord length of a single girder) at Reynolds number, Re=4×104. The aerodynamic coefficients of the prototype deck with gap ratio of 73.3% obtained from the present simulation were compared with the previous experimental and numerical data for different attack angles to validate the present numerical method. Particular attention is devoted to the fluctuating pressure distribution and forces, shear layer reattachment position, wake velocity and flow pattern in order to understand the effects of gap ratio on dynamic flow interaction with the twin-box bridge deck. The flow structure is sensitive to the gap, thus a change in L/C thus leads to single-side shedding regime at L/C≤25.6%, and co-shedding regime at L/C≥35.8% distinguished by drastic changes in flow structure and vortex shedding. The gap-ratio-dependent Strouhal number gradually increases from 0.12 to 0.27, though the domain frequencies of vortices shedding from two girders are identical. The mean and fluctuating pressure distributions is significantly influenced by the flow pattern, and thus the fluctuating lift force on two girders increases or decreases with increasing of L/C in the single-side shedding and co-shedding regime, respectively. In addition, the flow mechanisms for the variation in aerodynamic performance with respect to gap ratios are discussed in detail.

• Transactions on Electrical and Electronic Materials
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• 제18권3호
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• pp.125-128
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• 2017

This study is on how ohmic area etching affects the buffer breakdown voltage of AlGaN/GaN HEMT. The surface morphology of the ohmic metal can be improved by whole etching on the ohmic area. The buffer breakdown voltages of the samples with whole etching on the ohmic area were improved by the suppression of the metal spikes formed under the ohmic contact regions during high-temperature annealing. The samples with selective etching on the ohmic area were investigated for comparison. In addition, the buffer leakage currents were measured on the different radii of the wafer, and the uniformity of the buffer leakage currents on the wafer were investigated by PL mapping measurement.

• Journal of Ecology and Environment
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• 제32권2호
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• pp.87-96
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• 2009

Pinus thunbergii plantations in Pohang-si, Gyeongsangbuk-do, Korea, are of low ecological quality, with arrested succession and a high proportion of ruderal species. To improve the quality of the habitat, we created canopy gaps ($\sim42\;m^2$) and monitored changes in abiotic (light availability, canopy openness) and biotic (survival and growth of seedlings and understory communities) variables in 2007 and 2008 in plots that had received one of five types of treatment: cutting of canopy trees and removal of the understory (CU), cutting of canopy trees only (C), girdling of canopy trees and removal of the understory (GU), girdling of canopy trees (G) or control. Each treatment was applied to three replicate plots. Abiotic variables did not significantly differ among treatments. Survival rates of target species were slightly lower in the CU, G and control conditions. Based on logistic regression analysis, the only significant growth factor affecting survival was height growth. Positive effects of seedling height and leaf area growth on survival were also detected, but did not reach statistical significance. In treatment G, gradual improvement of overstory conditions and mitigation of competition by limitation of disturbance to the understory community were likely to have promoted seedling growth. There were no significant effects of gap treatments on changes in species abundance (cover and richness) and composition of understory between the study years. This result implies that the small gaps created in our study may be below the threshold size to affect understory growth. However, the results of this study are based on a short-term investigation of only two years. Long-term research is strongly recommended to clarify the effects of gap treatment on plant communities in afforested areas.