• 한국막학회:학술대회논문집
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• 한국막학회 2008년도 춘계 총회 및 학술발표회
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• pp.33-47
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• 2008

Non-equilibrium (irreversible) themodynamics is used to investigate colloidal back-diffusion during crossflow membrane filtration. The chemical potential is generalized as a superposition of equilibrium and irreversible contributions, originating from Brownian and shear-induced diffusion, respectively. As a result, an effective drag force is derived using the irreversible thermodynamics for a particle undergoing both Brownian and shear-induced diffusion in a sheared concentrated suspension. Using the drag force, a hydrodynamic force bias Monte Carlo method is developed for crossflow membrane filtration to determine the critical flux of hard sphere suspensions. Effects of shear rate and particle size on the critical flux are studied, and results show a good agreement with experimental observations reported in the literature.

• Food Science and Biotechnology
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• 제18권1호
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• pp.202-206
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• 2009

Drying characteristics of fresh Korean-type rehmannia (jiwhang) noodle was investigated to determine drying kinetic parameters under the experimental conditions of 5 temperatures (30, 40, 60, 80, and $90^{\circ}C$). Drying curve of the noodle showed a biphasic pattern of decrease in drying rate with initial rapid drying followed by slow dehydration as the progress in drying. In all drying conditions, only falling drying rate period was observed and the drying rate of the noodle was greatly influenced by the drying temperature. The effective diffusion coefficients ($D_{eff}$) were determined by the diffusion model and their temperature dependency was determined using an Arrhenius equation. The activation energy ($E_a$) values for the drying of the noodle were 19.94 and 21.09 kJ/mol at the initial and the latter stage of dehydration, which were comparable to those of pasta or Japanese udong dehydration.

• Transactions on Electrical and Electronic Materials
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• 제5권6호
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• pp.211-214
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• 2004

We developed a new systematic calibration procedure which was applied to the calibration of the diffusivity, segregation and TED model of the indium impurity. The TED of the indium impurity has been studied using 4 different groups of experimental conditions. Although the indium is susceptible to the TED, the RTA is effective to suppress the TED effect and maintain a steep retrograde profile. Like the boron, the indium shows significant oxidationenhanced diffusion in silicon and has segregation coefficients at the $Si/SiO_2$ interface much less than 1. In contrast, however, the segregation coefficient of indium decreases as the temperature increases. The accuracy of the proposed technique is validated by SIMS data and $0.13 {\mu}m$ device characteristics such as $V_{th}$ and $Id_{sat}$ with errors less than $5 \%$ between simulation and experiment.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.233-236
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• 2004

The purpose of this paper is to evaluate performance on reducing the chloride diffusion of surface treatment systems with elapsed time, treatment thickness, treatment frequency, and the types of surface treatment - coating, penetrator, and both all. Based on this paper, the guideline to applicate surface treatment systems will be established and comprehended how effective the resistance of chloride diffusion is. The selection of surface treatment materials and thickness to acquire service life of target will be possible. It is also expected to select optimum surface treatment system groups to resist chloride diffusion effectively and to estimate increased service life as the effect of durability enhancement.

• E2M - 전기 전자와 첨단 소재
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• 제10권7호
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• pp.682-691
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• 1997

We have investigated the guided optical properties of a Ti:LiNbO$_3$optical waveguide which was fabricated by Ti-diffusion in an air atmosphere and proposed an effective polishing method of waveguide endfaces. And the results of guided optical mode and fabrication condition were obtained as follows; \circled1 propagation loss : 0.53 dB/cm \circled2 mode size : horizontal/vertical=12.5${\mu}{\textrm}{m}$ \circled3 mode mismatch : 1.7 dB \circled4 diffusion temperature : 105$0^{\circ}C$, time : 8 hours \circled5 atmosphere : air

• 한국표면공학회지
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• 제32권3호
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• pp.433-439
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• 1999

In this study, the diffusion barrier properties of $1000\AA$ thick molybdenum compounds (Mox=1-5 Si) were investigated using sheet resistance measurements, X-ray diffractometry (XRD), and Rutherford back scattering spectrometry (RBS). Each barrier material was deposited by the de and rf magnetron co-sputtering of Mo and Si, respectively, and annealed at $500-700^{\circ}C$ for 30 min in vacuum. Each barrier material was failed at low temperatures due to Cu diffusion through grain boundaries and defects of barrier thin films or through the reaction of Cu with Si within Mo-barrier thin films. It was found that Mo rich thin films were less effective than Si rich films to Cu penetration activating Cu reaction with the substrate at a temperature higher than $500^{\circ}C$.

• Asian Journal of Innovation and Policy
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• 제8권1호
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• pp.141-161
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• 2019

A considerable amount of research has been directed at subsistence markets in the recent past with the belief that these markets can be tapped profitably by marketers. Consequently, such markets have seen the launch of a number of innovative products. However, marketers of such forecasts need timely and accurate forecasts regarding the diffusion of their products. The Bass model has been widely used in marketing management to forecast diffusion of innovative products. Given the idiosyncrasies of subsistence markets, such forecasting requires an understanding of effective estimation techniques of the Bass model and their use in subsistence markets. This article reviews the literature to achieve this objective and find out gaps in research. A finding is that there is a lack of timely estimates of Bass model parameters for marketers to act on. Consequently, this article sets a research agenda that calls for timely forecasts at the takeoff stage using appropriate estimation techniques for the Bass model in the context of subsistence markets.

• Telecommunications review
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• 제25권4호
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• pp.605-621
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• 2015

The diffusion of smart devices has greatly influenced the market dynamics of the telecommunications industry. The competition paradigm has shifted from individual firm-based competition to ecosystem-based competition. To satisfy the diverse needs of market customers, it has become more important for telecommunications companies to form alliances with complementary partners in the ecosystem. This study empirically investigates the influence of ecosystem-based alliance formations on the financial performance of firms in the Korean telecommunications market. Specifically, the impact of a CPND (Content, Platforms, Networks, and Devices) alliance in the ICT (Information and Communications Technology) sector on firms' profitability is examined using a structural equation model. The results indicate that before the diffusion of smart devices, ecosystem-based alliance formations with other firms in the ICT ecosystem were not effective for enhancing profitability. However, after this diffusion, alliance formation between members of the value chain in the ICT ecosystem contributed significantly to firms' financial performance. This implies that recent alliances with firms that are constituents of the ICT ecosystem are an important element of profit generation in the ICT market in Korea.

• Korean Chemical Engineering Research
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• 제56권3호
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• pp.430-434
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• 2018

본 연구에서는 잔류 메틸렌 클로라이드 제거를 위한 마이크로웨이브를 이용한 파클리탁셀 건조에서 유효확산계수 및 물질전달계수를 조사하였다. 모든 온도(35, 45, $55^{\circ}C$)에서 건조 초기에 많은 양의 잔류 메틸렌 클로라이드가 제거되었으며 건조 온도가 증가할수록 건조 효율은 증가하였다. 건조 온도가 증가할수록 파클리탁셀의 유효확산계수($1.299{\times}10^{-13}{\sim}2.571{\times}10^{-13}m^2/s$)와 물질전달계수($1.625{\times}10^{-11}{\sim}4.857{\times}10^{-11}m/s$)는 증가하였다. 또한 낮은 Biot 수(0.0100~0.0151)로부터 건조의 진행이 주로 파클리탁셀의 외부확산에 의해 조절됨을 알 수 있었다.

• 농업과학연구
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• 제47권3호
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• pp.519-532
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• 2020

Because lotus root has a short shelf life, the quality easily deteriorates. Thus, the harvested lotus roots are processed into a variety of products. Drying is one of the simplest food preservation methods, which can increase food stability. However, the convective drying method takes a long time and requires high energy consumption. Combination drying methods have emerged to overcome the limitations of the convective drying method. This study investigated the drying characteristics of lotus root and determined the optimal drying model of lotus root depending on the microwave and hot-air combination drying conditions. The lotus root slices (5 mm in thickness and 40 mm in diameter) were dried by different drying conditions that were combined with three microwave power levels (50, 100, and 150 W) and two hot air temperatures (50 and 60℃) at a velocity of 5 m·s^-1. Eight drying models were tested to evaluate the fit to the experimental drying data, and the effective moisture diffusion (D_eff) values of the lotus root slices dried by combination drying were estimated. The combination drying time of the lotus root was significantly reduced with the high air temperature and microwave power. The effective moisture diffusion (D_eff) of lotus root was more affected by the air temperature than microwave power intensity. Logarithmic model was most suitable to describe the drying curve of lotus root in the microwave-hot air combination drying method.