• Macromolecular Research
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• v.17 no.9
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• pp.714-717
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• 2009

Hole transport copolymers consisting of 3,4-ethylenedioxythiophene (EDOT) and N-4-butylphenyl-N,N-diphenylamine (BTPA) were synthesized by oxidative coupling reaction using $FeCl_3$ as an oxidant. These copolymers showed good solubility and their thin films showed sufficient morphological stability. The copolymers showed an absorption maximum around 320 nm. Copolymers had an oxidation peak at approximately $1.03{\sim}1.14V$ versus the Ag/AgCl electrode. The hole mobility increased with increasing portion of the EDOT unit. The hole mobility of the copolymer containing 57% of the EDOT unit showed the highest mobility of $3{\times}10^{-5}cm^2/V{\cdot}s$.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10b
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• pp.712-717
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• 1998

Represtressed preflex beams do not allow tensile stress under service load by introducing additional prestressing at the lower concrete of beams. In this study, optimal design of represetressed preflex beams are numerically investigated. Design variables are dimension of plate girder. Object function is the total weight of plate girder. Constraints of the stress of plate girder and upper and lower concrete flange and lower and upper bounds on the design variables are imposed. Structural analysis is performed by D.A.R.P.(Design and Analysis of Represtressed Preflex beams). For numerical optimization, ADS(Garret N. Vanderplaats) program is used. From result of application examples, optimum designs of different cases are successfully obtained. The design program developed in this study seems efficient and robust for the optimization of represtressed preflex beams.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.281-282
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• 2007

$Mg_4Nb_2O_9$ (MN) ceramics have been prepared by a sol-gel method. The powder characteristics, phase evolution, and microwave dielectric properties of the MN were investigated in various processing conditions such as sol-gel compositions, calcination, and sintering temperatures. A Qxfo value of 111,717 GHz with a ${\varepsilon}_r$ of 10.59 and a ${\tau}_f$ of $+1.736\;ppm/^{\circ}C$ was obtained after sintering at $1300^{\circ}C$ for 5 h.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.15 no.4
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• pp.356-361
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• 1986

An optimum design condition for a basic refrigeration cycle is defined as the condition which minimizes the total cost of heat exchanges (condenser and evaporator) and compressor for the refrigeration effect. Thermodynamic properties of ammonia (R717) are approximated by rational functions in order to obtain the optimum condition for a basic refrigeration cycle. Optimum condition depends on the heat capacity rates (mass flow rate times specific heat) of cooling water and brine used in condenser and evaporator. The difference between the cooling water temperature and condensation temperature at the optimum condition increases as the heat capacity rates and the coat of heat exchangers relative to the cost of compressor increase. Numerical examples of optimum conditions are obtained when the condensation temperature is $30^{\circ}C$ and the evaporator temperature is $-10^{\circ}C$.

• Bulletin of the Korean Mathematical Society
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• v.60 no.3
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• pp.717-732
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• 2023

The goal of this paper is to analyze the generalized m-quasi-Einstein structure in the context of almost Kenmotsu manifolds. Firstly we showed that a complete Kenmotsu manifold admitting a generalized m-quasi-Einstein structure (g, f, m, λ) is locally isometric to a hyperbolic space ℍ²ⁿ⁺¹(-1) or a warped product ${\tilde{M}}{\times}{_{\gamma}{\mathbb{R}}$ under certain conditions. Next, we proved that a (κ, µ)'-almost Kenmotsu manifold with h' ≠ 0 admitting a closed generalized m-quasi-Einstein metric is locally isometric to some warped product spaces. Finally, a generalized m-quasi-Einstein metric (g, f, m, λ) in almost Kenmotsu 3-H-manifold is considered and proved that either it is locally isometric to the hyperbolic space ℍ³(-1) or the Riemannian product ℍ²(-4) × ℝ.

• Journal of Physiology & Pathology in Korean Medicine
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• v.27 no.6
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• pp.717-729
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• 2013

Bioelectrical Impedance Analysis (BIA) is a non-invasive and low-cost technique that estimates body composition based on the distribution of water and electrolytes in the body by analyzing body's electrical responses to source voltages. In this work, we carried out a systematic literature review on BIA researches in traditional East Asian medicine (TEAM). For comparison, firstly we introduced the concept and principle of BIA, and offered a general overview of research trends in western medical perspectives. We searched through the databases of Oriental Medicine Advanced Searching Integrated System and DataBase Periodical Information Academic for the articles published between 1994 and 2013, with keywords such as 'BIA', 'bioelectrical impedance' and 'impedance'. Among the rough-searched 274 articles, we finally selected 21 articles appropriate to the intended research field. The selected articles were categorized into diagnosis in Sasang medicine, impedance analysis in meridian system, and change of body composition after taking herbal medicine. We found that most of BIA researches in TEAM were preliminary and remained in the peripheral levels which is far behind the western medical research activities. Therefore, more efforts are needed to study BIA in association with major subjects such as pattern identification or physiological/pathological phenomena. In addition, methodological breakthrough of BIA is possible by applying the diagnostic concepts of the TEAM in relation to the balance of Qi and Blood.

• Korean Journal of Breeding Science
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• v.42 no.6
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• pp.717-720
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• 2010

A new cultivar of Euphorbia milii, 'Panorama' was developed at Cactus Research Institute, Gyeonggi-do Agricultural Research & Extension Services in 2009. 'Gabi' and 'Maxi' were crossed in 2001 and three $F_1$ seedlings were obtained. Pedigree selection was performed in 2002. One line was finally selected and named as 'Panorama' through the test of specific character from 2007 to 2009. The new cultivar 'Panorama' has green and pink colored bract, and it has 2~3 each of inflorescence number, 2.0 cm of bract width, 4.3 each of lateral shoot and 14.9 cm of plant height. Characters of the cultivar can be maintained by vegetative propagation.

• Journal of the Korean Institute of Gas
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• v.18 no.4
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• pp.13-20
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• 2014

In natural gas distribution system, gas pressure is regulated correspond to requirement using throttle valve which is releasing huge pressure energy as useless form. The waste pressure can be recovered by using turbo machinery devices such as a turbo expander. In this process, excessive temperature drop occurs due to Joule-Thompson effect during the expansion process. Installing natural gas boiler before or after the turbo expander prevents temperature drop. Fuel cell or gas engine hybrid system further improve the efficiency, but 1~2% of total transporting natural gas is used for operating the hybrid system. In this study, a heat pump system is proposed as a preheating device which can be operated without using transporting natural gas. Thermodynamic analysis on evaporating and condensing temperatures and refrigerants is conducted. Results show that R717 is proper refrigerant for the hybrid system with high COP and low turbine work within the defined operating conditions. In domestic usage in Korea, the heat pump system has more economic feasibility owing to natural gas being imported with a high price of LNG form.

• Journal of Periodontal and Implant Science
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• v.33 no.4
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• pp.717-728
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• 2003

This study was performed to evaluate the difference of the bone-to-implant contact according to the surface roughness of the implants. Two beagles were used in the experiment. Extraction of the all premolars was performed in the mandible. In 3 months of healing, screw-shaped pure titanium machined surface implants (Implantium(R), Dentium Co. Korea), implants blasted with 45${\mu}m$ $TiO_2$ particles, (Implantium(R), Dentium Co. Korea) and implants blasted with 100${\mu}m$ $TiO_2$ particles (Implantium(R), Dentium Co. Korea) in diameter 3.4mm and length 6mm were installed in the edentulous mandible. Each dog was sacrificed at 4, 12 weeks after placement and then nondecalcified specimens were prepared for histologic analysis. The results of this study were as follows. 1. At 4 , 12 weeks after the surgery, bone-to-implant contact in the surface blasted with $TiO_2$ particles was higher than that in the pure titanium machined surface respectively. 2. Osseointegration in the surface blasted with 45${\mu}m$ $TiO_2$ particles was more increased than that in the surface blasted with 100${\mu}m$ $TiO_2$ particles. 3. Bone-to-implant contact was increased with time independent of surface roughness. 4. Bone formation was in the outfolded area more than inside the threads independent of surface roughness. From the above results, we were able t o find the most bone-to-implant contact in 45${\mu}m$ $TiO_2$ blasted implant.

• Horticultural Science & Technology
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• v.30 no.6
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• pp.709-717
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• 2012

To establish the standard of ripe kiwifruit sorting, near infrared (NIR) spectroscopy was performed on kiwifruit sampled from three farms. Destructive measurements of flesh firmness, soluble solids content (SSC), and acidity were performed and compared to measurement using NIR reflectance spectrums from 408 to 2,492 nm. NIR predictions of those quality factors were calculated using the modified partial least square regression method. Flesh firmness was predicted with a standard error of prediction (SEP) of 3.32 N and with a correlation coefficient ($R^2$) of 0.88. SSC was predicted with SEP of $0.49^{\circ}Brix$ and with $R^2$ of 0.98. Acidity was predicted with SEP of 0.28% and with $R^2$ of 0.91. Kiwifruit ripened at $20^{\circ}C$ for 15 days showed uneven qualities with normal distribution. Considering the SEP of each parameter, kiwifruit after ripening treatment could be non-destructively predicted their qualities and sorted by flesh firmness or soluble solids content through NIR prediction.