• 전기화학회지
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• 제5권4호
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• pp.178-182
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• 2002

The electrochemical behavior of binder-free carbon anode, comprising of only artificial and natural graphite (AG and NG) particles, for intercalation and deintercalation of lithium ion $(Li^+)$ in aluminum chloride (AICI_3)-I-ethyl­3-methylimidazolium chloride (EMIC)-lithium chloride (LiCl)-thionyl chloride $(SOCI_2)$ room-temperature molten salt (RTMS) was studied. Binder-free carbon electrodes were fabricated using electrophoretic deposition (EPD) method. The binder-free carbon anodes provided a relatively flat charge and discharge potentials $(0\;to\;0.2V\;vs.\;Li/Li^+)$ and current capabilities $(250-340mAh{\cdot}g^{-1})$ for the intercalation and deintercalation of $Li^+$. Stability of the binder-free carbon anodes for intercalation and deintercalation of 50 cycles was confirmed.

• Carbon letters
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• 제27권
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• pp.98-107
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• 2018

Free-standing electrodes of CuO nanorods in carbon nanotubes (CNTs) are developed by synthesizing porous CuO nanorods throughout CNT webs. The electrochemical performance of the free-standing electrodes is evaluated for their use in flexible lithium ion batteries (LIBs). The electrodes comprising CuO@CNT nanocomposites (NCs) were characterized by charge-discharge testing, cyclic voltammetry, and impedance measurement. These structures are capable of accommodating a high number of lithium ions as well as increasing stability; thus, an increase of capacity in long-term cycling and a good rate capability is achieved. We demonstrate a simple process of fabricating free-standing electrodes of CuO@CNT NCs that can be utilized in flexible LIBs with high performance in terms of capacity and cycling stability.

• 디지털산업정보학회논문지
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• 제14권4호
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• pp.229-239
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• 2018

In this paper, we propose a strategy of charging by analyzing the difference of path coefficient according to whether consumers are free or not, rather than presenting strategies for charging. Mobile devices have become so popular that they are called necessities. Companies have to adapt to the mobile environment and respond to the situation, and have to expand market opportunities strategically. In this study, we extend the technology acceptance model to analyze the incentives of consumers' behavior by analyzing the difference in the effect consumers perceive as a moderating variable, whether paid or free. Efforts to maximize company's inherent profit continue, and in particular, charging is a strategy that all companies should pursue in the mobile environments. It is necessary to grasp the degree of the consumer's response to free and charge. The model of satisfaction with the continuous use and the word-of-mouth intention, which is the behavior intention, is presented by adding parameters of satisfaction to the technology acceptance model. In addition, we try to derive implications by analyzing the influence of moderating effects of whether free or not.

• 유통과학연구
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• 제14권10호
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• pp.47-57
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• 2016

Purpose - This study's purpose is to investigate the market structure of the Korean duty free shop industry that has received recent attention from researchers and practitioners. By raising the question of whether or not the Korean duty free shop industry is unequivocally monopolistic, a wider viewpoint is provided. The study seeks to offer insights and managerial implications for marketers and policy makers who are in charge of regulating major Korean duty free shops. Research design, data, and methodology - The authors use secondary data from various sources, including Korea Customs Service and the Moodie Report, to investigate the structure of the duty free shop industry of Korea. Based on several theories, they present various criteria and statistical evidence such as K-firm concentration ratio, HHI, consumer substitutability, excess profit, and marketing costs. Results - In terms of consumer substitutability, it is difficult to confirm whether or not the Korean duty free shop industry is monopolistic. Notwithstanding monopoly characteristics in terms of market share, neither the company Lotte nor Shilla appear to have market dominating power. It is not easy for either of them to control prices or to achieve a much lower operational profit ratio due to a dominant bargaining power. Moreover, the license is not an economic rent. In this situation, it is not easy for these companies to obtain an excessive profit. Conclusions - Considering that most global duty free shops are trying to go upscale to improve bargaining power, it does not seem likely that rigid regulations are needed in the industry. Even though the Korean duty free industry ostensibly has a monopolistic structure, government and policy-makers should look beyond the surface. They should take global and other reasonable criteria into consideration when they establish or change regulation policies. Thorough understanding and appropriate support are needed for the Korean duty free shop industry. Additionally, duty free shops should position themselves as global companies struggling against unlimited international competition, rather than Korean domestic companies. At the same time, they need to give customers appropriate information about the benefits they provide.

• 대한기계학회논문집B
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• 제26권2호
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• pp.227-237
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• 2002

A numerical technique for simulating the aggregation of charged particles was presented with a Brownian dynamic simulation in the free molecular regime. The Langevin equation was used for tracking each particle making up an aggregate. A periodic boundary condition was used for calculation of the aggregation process in each cell with 500 primary particles of 16 nm in diameter. We considered the thermal force and the electrostatic force for the calculation of the particle motion. The electrostatic force on a particle in the simulation cell was considered as a sum of electrostatic forces from other particles in the original cell and its replicate cells. We assumed that the electric charges accumulated on an aggregate were located on its center of mass, and aggregates were only charged with pre-charged primary particles. The morphological shape of aggregates was described in terms of the fractal dimension. In the simulation, the fractal dimension for the uncharged aggregate was D$\_$f/ = 1.761. The fractal dimension changed slightly for the various amounts of bipolar charge. However, in case of unipolar charge, the fractal dimension decreased from 1.641 to 1.537 with the increase of the average number of charges on the particles from 0.2 to 0.3 in initial states. In the bipolar charge state, the average sizes of aggregates were larger than that of the uncharged state in the early and middle stages of aggregation process, but were almost the same as the case of the uncharged state in the final stage. On the other hand, in the unipolar charge state, the average size of aggregates and the dispersion of particle volume decreased with the increasing of the charge quantities.

• Korea-Australia Rheology Journal
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• 제19권2호
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• pp.51-59
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• 2007

A polyelectrolyte chain confined in a slit nanochannel exhibits a structural transition from the one in free space. In this paper, the effect of the long-range electrostatic interactions between the xanthan polyelectrolyte and the slit wall on the confined xanthan conformation is investigated via the Brownian dynamics simulation. A neutral and two negatively charged surfaces of polydimethylsiloxane (PDMS) and glass are combined to make four kinds of slit channels with different charge characteristics: i) neutral-neutral, ii) glass-glass, iii) neutral-PDMS and iv) neutral-glass walls. Their walls are characterized by uniform surface charge densities determined from experimental data of zeta potential. Both the nonmonotonic chain size variation and the loss of long-range bond vector correlation, previously observed under confinement in the PDMS-PDMS slit, are also found in the neutral slit, demonstrating the nonelectrostatic origin of such crossover behaviors. As expected, the effect of wall charges is negligible at sufficiently high medium ionic strength of 100mM but it becomes significant in the opposite limit of 0.01mM. In the latter case, the high charge density of glass walls strengthens the effective confinement of a negatively charged polyelectrolyte and produces a xanthan structure comparable to that confined in a much narrower neutral slit. The obtained structural data suggest the possibility of controlling the structure of confined polyelectrolytes by the modification of surface charge characteristics of micro/nanofluidic devices in combination with the adjustment of the medium ionic strength.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.128-128
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• 2012

We investigated the atomic and electronic properties of graphene grown by Pd silicidation and intercalation using LEED, STM, and ARPES. Pd was deposited on the 6H-SiC(0001) surface at RT. The formation of Pd silicide gives rise to breaking of Si-C bonds of the SiC crystal, which enables to release C atoms at low temperature. The C atoms are transformed into graphene from $860^{\circ}C$ according to the LEED patterns as a function of annealing temperature. Even though the graphene spots were observed in the LEED pattern and the Fourier transformed STM images after annealing at $870^{\circ}C$, the topography images showed various superstructures so that graphene is covered with Pd silicide residue. After annealing at $950^{\circ}C$, monolayer graphene was revealed at the surface. The growth of graphene is not limited by surface obstacles such as steps and defects. In addition, we observed that six protrusions consisting of the honeycomb network of graphene has same intensity meaning non-broken AB-symmetry of graphene. The ARPES results in the vicinity of K point showed the non-doped linear ${\pi}$ band structure indicating monolayer graphene decoupled from the SiC substrate electronically. Note that the charge neutrality of graphene grown by Pd silicidation and intercalation was sustained regardless of annealing temperature in contrast with quasi-free- standing graphene induced by H and Au intercalation. Further annealing above $1,000^{\circ}C$ accelerates sublimation of the Pd silicide layer underneath graphene. This results in appearance of the $(6r3x6r3)R30^{\circ}$ structure and dissolution of the ${\pi}$ bands for quasi-free-standing graphene.

• 대한화학회지
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• 제32권6호
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• pp.513-519
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• 1988

헥사메틸벤젠과 1,3,5-트리니트로벤젠과의 사이에 전하이동착물의 안정도에 미치는 압력과 온도의 영향을 사염화탄소용액내에서 분광광도법으로 연구하였다. 압력은 1, 200, 500, 1000, 1400 bar. 온도는 25, 40, $50^{\circ}C$사이에서 측정하였다. 착물의 평형상수는 압력 및 온도 증가와 더불어 증가 또는 감소하고 흡수계수는 대체로 증가함을 알았다. 이들 각 평형상수로부터 착물형성에 따른 부피, 엔탈피, 자유에너지 및 엔트로피 변화량을 구하였다. 도한 압력 증가에 의한 red-shift, 온도 증가에 의한 blue-shift 현상 및 압력 변화에 의한 진동자세기의 관계를 열역학함수와 관계지어 설명하였다.

• 한국산학경영학회:학술대회논문집
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• 한국산학경영학회 2004년도 추계학술연구발표회
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• pp.4-22
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• 2004

과거에는 많은 온라인 컨텐츠 회사들이 자신의 컨텐츠 서비스에 대하여 무료로 제공하는 경향이 있었다. 그러나 최근 수익모델의 한계에 부딪히며, 특히 온라인 광고수입에 대한 한계를 느끼기 시작하면서 자신들의 서비스에 요금을 부과하기 시작했다. 이 논문은 이론적인 모델을 통하여 온라인 컨텐츠 회사들이 왜 자신의 컨텐츠 서비스에 요금을 부과하게 되었는지를 광고수익과 시장변수에 따른 조건에 따라 살펴본다. 또한 기존의 오프라인 컨텐츠 회사들이 온라인시장에 진입할 때의 조건들과 균형가격을 살펴보면서, 온라인 컨텐츠 시장에서의 가격전략과 비즈니스모델에 관련된 시사점을 논의한다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -1
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• pp.367-370
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• 2000

It is shown that $I_{DDQ}$ testing is very useful for shipping fault-free CMOS ICs. However, test time of $I_{DDQ}$ testing is extremely larger than one of logic testing. In this paper, a new test input sequence generation methodology is proposed to reduce the test time of $I_{DDQ}$ testing. At first, it is Shown that $I_{DDQ}$ test time Will be denominated by charge supply current for load capacitance of gates whose output logic values are changed by test input vector application and the charge current depends on input sequence of test vectors. After that, a test input sequence generation methodology is proposed. The feasibility is checked by some experiments.riments.