• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.11
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• pp.736-739
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• 2014

In this paper, we propose a enhanced anti-corrosion property of the ground system by coating the CNT/PVDF composite film on it. Polymer material used for preventing the corrosion of ground system is polyvinylidene fluoride (PVDF), and conducting filler for obtaining conductivity of the composite film is multi-walled carbon nanotubes (MWCNTs). The MWCNTs were dispersed in the organic solvent of methyl ethyl ketone 2-butanone (MEK) with different concentration ratios, and the PVDF was solved in the MEK solvent with constant concentration ratio of 1 wt%. The CNT/PVDF composite solution was perpared by mixing and re-dispersing the CNT solution and the PVDF solution. Finally, the CNT/PVDF composite films were fabricated by the spray coating method using the above composite solution. Electrical conductivity, surface states, and anti-corrosion property of the CNT/PVDF composite films coated on the Cu substrate were evaluated. We found that the CNT/PVDF composite film showed relatively low resistance, hydrophobic surface state, and chemical stability. Consequently, we could improve the anti-corrosion property and maintain the electrical conductivity of the ground system by coating the CNT/PVDF composite film on it.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.2
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• pp.102-106
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• 2018

Recently, there has been an increasing interest in the use of graphene as electrode materials for supercapacitors. In this regard, graphene oxide (GO) films were prepared using GO slurry obtained by dispersing GO powder in deionized (DI) water. The degree of dispersion of GO powder in DI water depends on the concentration of GO slurry, pH, impurity content, GO particle size, types of functional groups contained in GO, and manufacturing method of GO powder. In this study, the dispersivity of the GO powder was improved by adjusting the pH using only DI water (without additives), and a uniform GO film was obtained. The GO film was reduced by exposure to xenon intense pulsed light for a few milliseconds, and the reduced GO film was used as electrodes of a supercapacitor. The supercapacitor was characterized using cyclic voltammetry (CV), charge-discharge cycle, and electrochemical impedance spectroscopy measurements, and the specific capacitance of the supercapacitor was found to be ~140 F/g from the CV data.

• Journal of the Korean Vacuum Society
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• v.20 no.1
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• pp.70-76
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• 2011

High-quality double-walled carbon nanotubes (DWCNTs) were synthesized by catalytic decomposition method at $800^{\circ}C$ using Tetrahydrofuran. The as-synthesized DWCNTs typically have catalytic impurities and amorphous carbon, which were removed by two-step purification process, consisting of thermal oxidation and H2O2, HNO3, HCl treatment. The DWCNT suspension was prepared by dispersing the purified DWCNTs in an aqueous sodium dodecylbenzenesulfonate solution with horn-type sonication. This was then sprayed on ITO glass to fabricate CNT field emitters. The quality of purified DWCNTs was estimated with X-ray diffraction and Thermal Gravity Analysis. The field emission properties were improved by increasing the process time of HCl treatment.

• Journal of Korean Medical classics
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• v.30 no.3
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• pp.167-180
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• 2017

Objectives : The purpose of this paper is to extinguish the debates surrounding the sentences found in Suwen Kailun that deal with flocking to stomach and closure in lung. The paper seeks to do this through studying the assertions of historical doctors and their theories regarding the topic. Methods : The interpretations of annotators regarding these sentences were studied, and text DB was searched to collect and analyze materials related to the theories of the relationship between stomach and lung. Results : The sentences of flocking to stomach and closure in lung, judging from their contexts, seem to be related to the symptom of Sanjiao ke or Liufu ke. However, they may be pointing to internal organs' ke as a whole based on the close relationship between stomach and lung. They could mean either the abnormality of mechanism of stomach and lung could cuase ke or that Zhuoqi could accumulate inside of stomach to cause phlegm-fluids thereby blocking thorax and causing cough. Theory of Warm disease, too, provides a number of treatment suggestions for stomach, lung damages such as supporting Yin and dispersing dampness. Conclusions : The study of the sentences regarding flocking to tomach and closure in lung is expected to not only provide an analysis of the sentences, but also provide a perspective and a method for clinical treatments.

• Ocean Systems Engineering
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• v.7 no.3
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• pp.179-193
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• 2017

Dynamic response analysis of offshore triceratops with stiffened buoyant legs under impact and non-impact waves is presented. Triceratops is relatively new-generation complaint platform being explored in the recent past for its suitability in ultra-deep waters. Buoyant legs support the deck through ball joints, which partially isolate the deck by not transferring rotation from legs to the deck. Buoyant legs are interconnected using equally spaced stiffeners, inducing more integral action in dispersing the encountered wave loads. Two typical nonlinear waves under very high sea state are used to simulate impact and non-impact waves. Parameters of JONSWAP spectrum are chosen to produce waves with high vertical and horizontal asymmetries. Impact waves are simulated by steep, front asymmetric waves while non-impact waves are simulated using Stokes nonlinear irregular waves. Based on the numerical analyses presented, it is seen that the platform experiences both steady state (springing) and transient response (ringing) of high amplitudes. Response of the deck shows significant reduction in rotational degrees-of-freedom due to isolation offered by ball joints. Weak-asymmetric waves, resulting in non-impact waves cause steady state response. Beat phenomenon is noticed in almost all degrees-of-freedom but values in sway, roll and yaw are considerably low as angle of incidence is zero degrees. Impact waves cause response in higher frequencies; bursting nature of pitch response is a clear manifestation of the effect of impact waves on buoyant legs. Non-impact waves cause response similar to that of a beating phenomenon in all active degrees-of-freedom, which otherwise would not be present under normal loading. Power spectral density plots show energy content of response for a wide bandwidth of frequencies, indicating an alarming behaviour apart from being highly nonlinear. Heave, being one of the stiff degrees-of-freedom is triggered under non-impact waves, which resulted in tether tension variation under non-impact waves as well. Reduced deck response aids functional requirements of triceratops even under impact and non-impact waves. Stiffened group of buoyant legs enable a monolithic behaviour, enhancing stiffness in vertical plane.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.4
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• pp.415-422
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• 2008

This study was carried out to investigate the effect of operating and design conditions of gas dispersion type of absorber on $SO_2$ removal efficiency. pH difference between upper and lower part of gas dispersing plate of absorber was 0.2, which was relatively low. This was supposed that recirculation capacity of absorbing liquid between froth zone and reaction zone of absorber be increased by oxidation air injection through liquid riser which acted as liquid pump. Test results showed that $SO_2$ removal efficiency was more sensitive than absorber ${\Delta}P$. High $SO_2$ removal even at lower pH resulted from very low concentration of $HSO_3^-$ ion in absorbing liquid because of direct supply of dissolved oxygen into froth zone. 96% of $SO_2$ removal efficiency was obtained under the condition of absorber pH 5.2, flue gas flow rate of $1,530\;Nm^3/hr$, inlet $SO_2$ concentration of 800 ppm, absorber ${\Delta}P$ of 250mmAq. The following equation by a multiple linear regression was obtained to describe the relationship between $SO_2$ removal and operating variables. $$f=1-{\exp}(-1.3939+1.060pH+0.0139{\Delta}P-0.00267G-0.000064SO_2Conc.),\;R^2=0.9719$$

• Korean Journal of Human Ecology
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• v.13 no.3
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• pp.477-484
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• 2004

This paper is an attempt to discuss theoretical and empirical issues embedded in a rapidly dispersing well-being lifestyle in Korea. Increase of people's interests in health and well-being reflects the fact that Korea has been developed socially and economically to the level for common people to pursue the quality of life beyond survival or basic standards of life. The term, well-being life style, was first constructed and has been dispersed through mass media. Media contributes to popularize health issues and to deliver the importance of lifestyle for health promotion to the general public. Well-being lifestyle, initiated by media and joined with commercialism, however, reveal certain negative sides as well. Health or healthy lifestyle in Western societies has been rooted theoretically in the change of health paradigm and the political emphasis on the lifestyle for health promotion in policy implications. Well-being lifestyle in Korea, in lack of theoretical and institutional foundations, is being substantially formed into distorted consumerism. Based on the sociological theories of stratification, it might be necessary to discuss the well-being consumerism in respect of tension among people with different consuming power and the destruction of solid market principles. Considering well-being consumerism as a risk factor to societal well-being, it is also necessary to examine conflicting or misleading information about well-being and to explore the scientific knowledge and principles. All these discussions and examination need to be done with interdisciplinary efforts. Especially, tasks for developing application principles for everyday life are on hands of researchers in living sciences.

• Journal of Adhesion and Interface
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• v.7 no.4
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• pp.32-38
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• 2006

A series of organic-inorganic hybrids, PCL/EP/$SiO_2$, involving epoxy resin and triethoxysilane-terminated polycaprolactone elastomer (PCL-TESi) were prepared via polymerization of diglycidyl ether of bisphenol A (DGEBA) with amine curing agent KB-2 and sol-gel process of PCL-TESi. The curing reactions were started from the initially homogeneous mixture of DGEBA, KB-2 and the PCL-TESi. The organicinorganic hybrids containing up to 4.95% (wt) of $SiO_2$ were obtained and characterized by FT-IR, transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA). It was experimentally shown that the swelling property in toluene, morphologies and thermal properties of the resulting hybrids were quite dependent on the contents of $SiO_2$. The crosslink network density decreases with increasing of the PCL-TESi. And in TEM, the phase separated morphology of these hybrids was found, which resulted from the coagulation of Si-O-Si networks resulting from $-Si(OC_2H_5)_3$ of PCL-TESi self-curing by hydrolytic silanol condensation, with the advancement of the curing reaction in the modified epoxy resin systems. Meanwhile, the change of the $SiO_2$ content made the morphologies changed from aggregated particles of Si-O-Si in the hybrid to nanocluster of interconnected Si-O-Si particles, then to aggregated Si-O-Si dispersing in the continuous cured epoxy phase again, and last to co-continuous interpenetrating network. The glass transition behavior of the hybrid material was cooperative motion of large chain segments, which were hindered by the inorganic Si-O-Si network. And in TG analysis, the characteristic temperature at 5% of weight loss was evidently increased from $120.5^{\circ}C$ of pure cured epoxy to $277.6^{\circ}C$ of 3.84% (wt) of $SiO_2$ modified epoxy due to the existence of Si-O-Si when PCL-TESi was added in the hybrid.

• The Korea Journal of Herbology
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• v.22 no.1
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• pp.49-52
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• 2007

Objectives: Asari Herba comes from the dried perennial herbaceous plant, Asarum sieboldii $M_{IQ}$., A. heterotropides $F_R$. SCHMIDT var. mandshuricum($M_{AXIM}$) $K_{ITAG}$. and A sieboldii $M_{IQ}$ var. seoulense $N_{AKAI}$., family Aristolochiaceae. This medicine is pungent in flavor(味辛), warm in nature(性溫), mildly toxic and affects the lung, kidney, and heart meridians. It is able to repel wind dispel cold(祛風散寒), remove the obstruction of the nose(宣通鼻竅), relieve pain(止痛) and warm the lungs to remove the retention of fluids(溫肺化飮). In a clinic it is prescribed for exterior syndrome of wine-cold type(風寒表證) manifested as headache and general pain. It is indicated for headaches, toothaches, bisyndrome of wind-cold-dampness type(風寒濕痺), etc. For many generations medical books have warned doctors that the dosage of Asari Herba should not be excessive because the pungent flavor has the effect of dispersing exopathogens from superficies of the body. The principle, 'Asari Herba should not exceed Jeon(錢, Qian, 3.0 gram)' is still considered to be relevant. Methods : Extensive research of several ancient medical texts has lead to the following conclusion. Results : The statement 'Asari Herba should not exceed Jeon' is a dosage which is used to prepare single recipe and powder. Conclusion : The definition of Jeon is not 1 Jeon(3.0 gram), but 1 Jeonbi(錢匕, Qianbi, 1.0 gram), moreover, the usage, collection. and refinement process are not in accordance with the contents of the ancient medical texts. A deeper study of Asari Herba's dosage in the future is expected to have interesting results.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.353-353
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• 2008

Carbon nanotubes (CNTs) are attractive for field emitter because of their outstanding electrical, mechanical, and chemical properties. Several applications using CNTs as field emitters have been demonstrated such as field emission display (FED), backlight unit (BLU), and X-ray source. In this study, we fabricated a CNT cathode using transparent ultra-thin CNT film. First, CNT aqueous solution was prepared by ultrasonically dispersing purified single-walled carbon nanotubes (SWCNTs) in deionized water with sodium dodecyl sulfate (SDS). To obtain the CNT film, the CNT solution in a milliliter or even several tens of micro-litters was deposited onto a porous alumina membrane through vacuum filtration process. Thereafter, the alumina membrane was solvated by the 3 M NaOH solution and the floating CNT film was easily transferred to an indium-tin-oxide (ITO) glass substrate of $0.5\times0.5cm^2$ with a film mask. The transmittance of as-prepared ultra-thin CNT films measured by UV-Vis spectrophotometer was 68~97%, depending on the amount of CNTs dispersed in an aqueous solution. Roller activation, which is a essential process to improve the field emission characteristics of CNT films, increased the UV-Vis transmittance up to 93~98%. This study presents SEM morphology of CNT emitters and their field emission properties according to the concentration of CNTs in an aqueous solutions. Since the ultra-thin CNT emitters prepared from the solutions show a high peak current density of field emission comparable to that of the paste-base CNT emitters and do not contain outgassing sources such as organic binders, they are considered to be very promising for small-size-but-high-end applications including X-ray sources and microwave power amplifiers.