• 대한산업공학회지
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• 제28권1호
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• pp.36-43
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• 2002

We analyze bulk service $M/G^{b}/1$ queues using the arrival time approach of Chae et al. (2001). As a result, the decomposition property of the M/G/1 queue with generalized vacations is extended to the $M/G^{b}/1$ queue in which the batch size is exactly a constant b. We also demonstrate that the arrival time approach is useful for relating the time-average queue length PGF to that of the departure time, both for the $M/G^{b}/1$queue in which the batch size is as big as possible but up to the maximum of constant b. The case that the batch size is a random variable is also briefly mentioned.

• Bulletin of the Korean Chemical Society
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• 제35권3호
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• pp.886-890
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• 2014

The properties of magnetic material of Nd-Fe-B are highly affected by various factors such as particle size, magnetic anisotropy, phase purity and crystal structure. Incorporation of excess neodymium was carried out in various percentages so that it will adjust the proportion of neodymium in the host crystal after reduction treatment and finally help to improve magnetic property of a material. The interdiffusion of Nd-Fe and boron was studied for various compositions and their effect on magnetic property was understood with theoretical concepts. The factors such as amount of hard and soft phase in the reduction treated product is also responsible for the possible exchange coupling between hard and soft phase magnets for better magnetic properties.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제2B권4호
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• pp.143-148
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• 2002

Up to now, DC-biased magnetic properties have been measured in one dimension (scalar). However, scalar magnetic properties are insufficient to clarify DC-biased magnetic properties because scalar magnetic properties can only impossibly consider the phase difference between the magnetic flux density B vector and the magnetic field strength H vector. Thus the magnetic field strength H and magnetic flux density B in magnetic materials must be directly measured as a vector quantity (two-dimensional). This paper presents measurement system to clarify the two-dimensional DC-biased magnetic properties.

• 한국염색가공학회지
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• 제2권1호
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• pp.8-13
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• 1990

The fading of dyed material by light has long been subject of investigation, yet surprisingly little is known of the fundamental photochemical reactions, because of mainly the complex nature of dye-fibre system. The effect of the chemical structure of dye on lightfastness has been mostly studied when there is substituents on the place satisfied Hammett rule. Therefore, in this investigation the effectiveness of chemical structures of Congo Red and Benzopurpurine 4B unsatisfied Hammett rule on dyeing property and lightfastness of cotton was studied. The results obtained from this study were as follows; 1. Highly polar solvents showed hypsochromic shift. 2. Adsorption isotherm curves of the two dyes were Freundlich type. And Congo Red showed good dyeing property in comparision with Benzopurpurine 4B. 3. The type of the FR curve of the two dyes was first-ordr curve. And the CF curves of the two dyes showed normal fading state during irradiation. 4. During irradiation, the Hue was changed on the part of yellowish. The Value was increasing and the Chroma was decreasing. 5. Benzopurpurine 4B showed good lightfastness in comparision with Congo Red.

• 대한기계학회논문집B
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• 제20권9호
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• pp.3015-3029
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• 1996

The notion of effective transport property of a heterogeneous medium implies that the medium is large enough that the ergodic theorem holds and local fluctuation of the property can be neglected. In case that the medium is not large enough compared to its characteristic microstructure length scale, the effective property fluctuates and differs from the value of the medium being large enough. As a representative transport phenomenon, diffusion was considered and the fluctuation of varying effective diffusion property, diffusion coarseness $C_k$, was defined as a quantifying parameter. Scaled effective diffusion property, $^*$>/k$_1$ and $C_k$ were computed for the two phase random media consisting of matrix of diffusion coefficient k$_1$ and spheres of diffusion coefficient k$_2$. Numerical simulations were performed by use of the so-called first passage time technique and data were collected for existing microstructure models of hard spheres(HS), overlapping spheres(OS) and penetrable concentric shells(PCS).

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2002년도 학술대회 논문집
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• pp.3-4
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• 2002

The stainless steel sheathed MgB$_2$ tapes with Cu addition were fabricated by PIT method without heat treatment. The $J_{c}$ value of 5,600 A/ $cm^{2}$and 16,000 A/$cm^{2}$ at 4.2 K and 5 T were obtained for the $MgB_{2}$ tape and 10 vol % of Cu added $MgB_{2}$ tape respectively. The $J_{c}$-B curve shows enhancement in J$_{c}$ under magnetic field, which suggests enhancement in flux pinning property with Cu addition.n.

• 열처리공학회지
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• 제21권1호
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• pp.26-32
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• 2008

Effects of annealing treatment on microstructure and mechanical property of co-sputtered TiNi thin films were studied. As-deposited films showed amorphous state. However, above annealing temperature of $500^{\circ}C$ martensite phase (B19'), precipitate phase ($Ti_2Ni$) and a small amount of parent phase ($B_2$) were present, and phase transformation behaviors were three multi-step phase transformations $B19^{\prime}{\rightarrow}B_2$ and $B_2{\rightarrow}R-phase$ and $R-phase{\rightarrow}B19^{\prime}$. Increase of martensite transformation temperature, increase of microhardness and Young's modulus of TiNi films annealed above $500^{\circ}C$ were discussed in terms of precipitate phase.

• 한국초전도ㆍ저온공학회논문지
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• 제15권4호
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• pp.48-52
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• 2013

This paper compares the features of second generation (2G) High Temperature Superconducting (HTS) field coil with those of magnesium diboride ($MgB_2$) field coil for a 10 MW class superconducting generator. Both coils can function effectively in their respective magnetic flux density range: 10-12 T for 2G HTS field coil, 2 T for $MgB_2$ superconducting field coil. Even though some leading researchers have been developing 10 MW class superconducting generator with 2G HTS field coil, other research groups have begun to focus on $MgB_2$ wire, which is more economical and suitable for mass production. However 2G HTS wire is still appealing in functions such as in-field property and critical temperature, it shows higher in-field property and critical temperature than $MgB_2$ wire.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제17권2호
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• pp.151-156
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• 2010

The object of the present paper is to introduce ${\Lambda}$-dual and the concept of sectional analyticity (Abschinitts-anatytique or AA property) of an FK-space.The motivation for AA-property is that a sequence space having AK-property possess AA-property.

• 대한수학회보
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• 제58권3호
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• pp.559-572
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• 2021

It is well known that every invariant harmonic function on the unit ball of the multi-dimensional complex space has the volume version of the invariant mean value property. In 1993 Ahern, Flores and Rudin first observed that the validity of the converse depends on the dimension of the underlying complex space. Later Lie and Shi obtained the analogues on the unit ball of multi-dimensional real space. In this paper we obtain the half-space analogues of the results of Liu and Shi.