• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.6
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• pp.119-126
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• 2004

In order to elucidate the modes of double-droplet combustion speed in premixed spray flame, the difference between flame propagation speed and droplet cluster disappearance speed are experimentally investigated using a premixed spray burner system, It was confirmed that flame speed concerned with premixed-mode combustion in the spray flame was approximately 2.0 m/s in average while mean disappearance speed of droplet clusters, which were dominated by diffusion-mode combustion in downstream of the flame, was evaluated as much as 0.45 m/s. It was clarified that both characteristics of premixed-mode and diffusion-mode combustion in spray flames are of much difference in nature, even though both speed, which are supposed to depend on local properties of the spray itself and flow conditions surrounding droplet clusters, are scattered in experiments.

• 한국연소학회:학술대회논문집
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• 1998.10a
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• pp.131-138
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• 1998

Flame characteristics in a double concentric burner has been studied experimentally. Air is supplied through a central nozzle, methane/air premixture is supplied in a inner annular part, and coflowing shield air is supplied to minimize outside disturbances. Depending on flow rate and concentration, various flame shapes can be observed. As the flow rate difference between central air jet and annular premixed jet is varied, several distinctive flames are observed. Conditions of partially premixed flames are further investigated; nozzle attached rich premixed flame, inner lifted flame, and outer lifted flame. Using the Abel transformation of digitized images of flames, cross- sectional images of flames can be obtained, from which overall structure of flames can be identified. PLIF measurement of OR radical was also conducted. OR radicals were mainly distributed in diffusion flame region. From the difference of OR distribution between nozzle attached and lifted flames, similarity of OR distribution between tribrachial flame and lifted flames in this study are observed.

• Advanced Composite Materials
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• v.17 no.3
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• pp.301-317
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• 2008

The energy release rate associated with crack growth in adhesive double cantilever beam (DCB) specimens, including the effect of residual stresses, was formulated using beam theory. Because of the rotation of the asymmetric arms in the adhesive DCB specimens due to temperature change, it is necessary to correct the evaluated fracture toughness of the DCB specimens, specifically in the case of a large temperature change. This study shows that the difference between the true toughness and an apparent toughness due to the consequence of ignoring residual stresses can be calculated for a given specimen geometry and thermo-mechanical properties (e.g. coefficient of thermal expansion). The calculated difference in the energy release rates based on the present correction method is compared with that from FEM in order to verify the present correction method. The residual stress effects on the evaluation of the adhesive fracture toughness are discussed.

• Journal of applied mathematics & informatics
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• v.8 no.1
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• pp.45-57
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• 2001

A parametric scheme is proposed for the numerical solution of the nonlinear Boussinesq equation. The numerical method is developed by approximating the time and the space partical derivatives by finite-difference re placements and the nonlinear term by an appropriate linearized scheme. The resulting finite-difference method is analyzed for local truncation error and stability. The results of a number of numerical experiments are given for both the single and the double-soliton wave. AMS Mathematics Subject Classification : 65J15, 47H17, 49D15.

• Kyungpook Mathematical Journal
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• v.48 no.4
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• pp.613-622
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• 2008

In this article we introduce some difference sequence spaces defined by Orlicz function and study different properties of these spaces like completeness, solidity, symmetricity etc. We establish some inclusion results among them.

• The Journal of the Acoustical Society of Korea
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• v.14 no.3
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• pp.28-36
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• 1995

In this paper, a double loop control model using leaky delay LMS algorithm are proposed for active noise control. The proposed double loop control model estimates the loudspeaker characteristic and the error path transfer function with on-line using only gain and acoustic time delay to reduce computation burden. The control of error signal through double loop control scheme makes the more robust cntrol system. The input signal of filter to estimate acoustic time delay is used difference between input signal of input microphone and adaptive filter output. And also, in nonstationary environments, the leaky delay LMS algorithm is employed to counteract parameter drift of delay LMS algorithm. For practical noise signal, the proposed double loop control model reduces noise level about 12.9 dB.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.13 no.2
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• pp.180-187
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• 2002

Background and Objectives : The operation Double Opposing Z-Plasty, has been used for improving VPI function in the submucous cleft palate. However, few reports on the effects of the speech change were presented. The purpose of this study is to compare the difference of nasality and nasalance, parents satisfaction between before and after this operation and to consider how much improvement in speech. Materials and Methods : Ten submucous cleft palate children who underwent double opposing Z-plasty were analyzed. We retrospectively studied nasalance, auditory perception (nasality) with hypernasality, patients satisfaction, speech evaluation by using charts review, video tape, telephone interview. Results : In 8 patients of 10 submucous cleft palate, hypernasality reduced and speech intelligibility was higher and mean 0.35 point was increased in the velum length after operation. After operation, nasality was improved (2.0 point) and level of nasal emission decreased. Regarding satisfaction of this operation, scale was mean 2.8 (5 point-scale) : 8 parents were satisfied in the resonance, 3 parents were satisfied articulation. The reason of dissatisfaction was mostly compensatory articulation. Conclusion : To improve of speech in the submucous cleft palate, speech therapy afterthis operation as well as successful surgery should be considered.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.05a
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• pp.57-60
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• 2008

This study investigated the results of insulation heat curing method using double layer bubble sheet in slab concrete and mass concrete in cold weather environment. First of all, when double bubble sheets are applied, it was shown that slab concrete was protected from early freezing by remaining between 6 and 15℃ even in case outside temperature drops -9℃ below zero until the 2nd day from piling, and in the case of mass concrete, with the maximum temperature difference between the center and surface less than 4℃, crack occurrence index was close to 2 and no hydration heat crack occurred by internal constraint. The insulation heat preservation curing method using the double bubble sheet applied in this field prevented early freezing owing to stable curing temperature management, deterring concrete strength development delay at low temperature, and obtained the needed strength. Also, it was proven that the method is highly effective and economic for cold weather concrete quality maintenance through curing cost reduction like construction period shortening and labor cost reduction, etc by reducing the process of temporary equipment installation and disassembling.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.909-914
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• 2006

The purpose of this study is to analyze the thermal of DFS(double Facade System) and curtain wall in the heating period. The physical difference between curtain wall and double facade on thermal performance has been tested at the newly constructed laboratory, which can turn $360^{\circ}$ to confirm the characteristic of a facade with the various directions. This study divide on 'ventilated, airtight' and 'heated or unheated' conditions from the CASE 1, 2, 3, 4. The results showed thermal performance of double facade system which has been better than curtain wall. The heating energy of DFS reduced $8%{\sim}10%$ of energy consumption. comparable to SFS in experemted results. In view of the researching results so far achieved, the research came to a conclusion, that the curtain wall can save the energy in the heating period than a curtain wall.

• Development and Reproduction
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• v.13 no.3
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• pp.191-198
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• 2009

In an attempt to simultaneously produce two human proteins, hGH and hG-CSF, in the milk of transgenic mice, we constructed goat $\beta$-casein-directed hGH and hG-CSF expression cassettes individually and generated transgenic mice by co-injecting them into mouse zygotes. Out of 33 transgenic mice, 29 were identified as double transgenic harboring both transgenes on their genome. All analyzed double transgenic females secreted both hGH and hG-CSF in their milks. Concentrations ranged from 2.1 to $12.4\;mg/m{\ell}$ for hGH and from 0.04 to $0.13\;mg/m{\ell}$ for hG-CSF. hG-CSF level was much lower than hGH level but very similar to that of single hG-CSF mice, which were introduced with hG-CSF cassette alone. In order to address the causes of concentration difference between hGH and hG-CSF in milk, we examined mRNA level of hGH and hG-CSF in the mammary glands of double transgenic mice and tissue specificity of hG-CSF mRNA expression in both double and single transgenic mice. Likewise protein levels in milk, hGH mRNA level was much higher than hG-CSF mRNA, and hG-CSF mRNA expression was definitely specific to the mammary glands of both double and single transgenic mice. These results demonstrated that two transgenes have distinct transcriptional potentials without interaction each other in double transgenic mice although two transgenes co-integrated into same genomic sites and their expressions were directed by the same goat $\beta$-casein promoter. Therefore goat $\beta$-casein promoter is very useful for the multiple production of human proteins in the milk of transgenic animals.