• Polymer(Korea)
• /
• v.26 no.4
• /
• pp.422-430
• /
• 2002

The kinetics of polycondensation of bishydroxyethyl naphthalate has been studied in the range of 241 -$260^{\circ}C$ using antimony trioxide catalyst. The reaction was performed in a batch reactor and the concentration of reaction mixture was measured with HPLC. The activation energy values of forward and reverse reaction determined from molecular species model were found to be 19.7 and 31.4 kcal/mole, respectively, and the equilibrium constants were in the range of 1.4-2.0, which were larger than that of polycondensation of PET and varied to some degree with temperature. It was confirmed by applying the Flory's distribution function that the reaction rate of the hyroxyethyl group does not depend on the molecular size. By applying functional group model, we observed that there was few difference between the activation energy of the forward reaction and that of reverse reaction, therefore the equilibrium constant has almost constant value of 1.4. The rate constants obtained from functional group model was about 3-4 times larger than that from molecular species model, which showed that both model explains the reaction system well. Although the molecular species model should predict the concentration of as many as ten molecules, it fits for the experimental results well.

• Polymer(Korea)
• /
• v.35 no.2
• /
• pp.99-105
• /
• 2011

To optimize the properties of compounds, effective mixing is of importance to achieve adequate distribution and dispersion of filler particles. A variety of mixing elements have been used for twin-screw extruders in order to improve the mixing efficiency. In this study, the effects of 10 screw configurations on the filler dispersion were investigated for the calcium carbonate filled polystyrene processed in a co-rotating twin-screw extruder. The state of filler dispersion was characterized by equipped with a photodiode. The experimental results indicated that the type and position of mixing elements primarily affected the degree of filler dispersion.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
• /
• v.30 no.3
• /
• pp.62-75
• /
• 2017

Objectives : The aim of this study is to evaluate possibility of DITI as prognosis evaluation tool of facial palsy. Methods : We investigate prognosis of facial palsy through EMR(Electronic Medical Record) of inpatient from December 2016 to June 2017. We evaluated the sex, age distribution, length of hospital stay, paralysis site, number of treatment after discharge, change of H-B Grade at entrance and exit, temperature difference of both sides of DITI, and Nerve Conduction Study(NCS) with reference to EMR recorded symptom change. Results : 1. Significant correlations were not found between DITI and House-Brackmann Grade change, NCS(%), the date of admission. 2. There was a negative correlation between NCS(%) and hospitalization period in patients with facial palsy. The higher the NCS, the faster the recovery rate of facial palsy. 3. In patients with facial palsy, the temperature difference between the two sides after the DITI image shows that the affected side tends to be lower than the normal side. Conclusions : In this study, only DITI temperature difference between both sides of face is not significant in determining the prognosis of facial palsy. Further research is needed to conduct DITI at the same time and to improve accuracy through a sufficient assessment of the degree of facial palsy.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.32 no.2 s.57
• /
• pp.93-97
• /
• 2006

Staphylococcus aureus is found on the skin of $78{\sim}100%$ of children and adults with atopic dermatitis (AD) but only on the skin of $2{\sim}25%$ of healthy subjects. It is known that S. aureus and their endotoxins as superantigen have important roles in the exacerbation and prolongation of AD. This study was carried out for the detection of S. aureus in the skin of AD, age, sex, outbreak age of AD, treatment duration, aggravation season, and the relation of ooze and S. aureus. Most patients (84%) with AD show colonization of the skin with S. aureus and there is a correlation between the degree of colonization and the serous exudate. It seems likely that the inhibition of S. aureus is associated with improvement in the skin of AD patients.

• Geophysics and Geophysical Exploration
• /
• v.7 no.1
• /
• pp.45-50
• /
• 2004

This paper describes a method of detecting formation boundaries, and permeable fractures, from frequency-domain Stoneley wave logs. Field data sets were collected between the depths of 330 and 360 m in well EE-4 in the Higashi-Hachimantai geothermal field, using a monopole acoustic logging tool with a source central frequency of 15 kHz. Stoneley wave amplitude spectra were calculated by performing a fast Fourier transform on the waveforms, and the spectra were then collected into a frequency-depth distribution of Stoneley wave amplitudes. The frequency-domain Stoneley wave log shows four main characteristic peaks at frequencies 6.5, 8.8, 12, and 13.3 kHz. The magnitudes of the Stoneley wave at these four frequencies are affected by formation properties. The Stoneley wave at higher frequencies (12 and 13.3 kHz) has higher amplitudes in hard formations than in soft formations, while the wave at lower frequencies (6.5 and 8.8 kHz) has higher amplitudes in soft formations than in hard formations. The correlation of the frequency-domain Stoneley wave log with the logs of lithology, degree of welding, and P-wave velocity is excellent, with all of them showing similar discontinuities at the depths of formation boundaries. It is obvious from these facts that the frequency-domain Stoneley wave log provides useful clues for detecting formation boundaries. The frequency-domain Stoneley wave logs are also applicable to the detection of a single permeable fracture. The procedure uses the Stoneley wave spectral amplitude logs at the four frequencies, and weighting functions. The optimally weighted sum of the four Stoneley wave spectral amplitudes becomes almost constant at all depths, except at the depth of a permeable fracture. The assumptions that underlie this procedure are that the energy of the Stoneley wave is conserved in continuous media, but that attenuation of the Stoneley wave may occur at a permeable fracture. This attenuation may take place at anyone of the four characteristic Stoneley wave frequencies. We think our multispectral approach is the only reliable method for the detection of permeable fractures.

• Geophysics and Geophysical Exploration
• /
• v.7 no.1
• /
• pp.80-87
• /
• 2004

During excavation work for the construction of a highway bridge in a limestone area in Korea, several cavities were found, and construction work was stopped temporarily. Cavities under the bridge piers might seriously threaten the safety of the planned bridge, because they could lead to excessive subsidence and differential settlement of the pier foundations. In order to establish a method for reinforcement of the pier foundations, borehole radar reflection and tomography surveys were carried out, to locate cavities under the planned pier locations and to determine their sizes where they exist. Since travel time data from the crosshole radar survey showed anisotropy, we applied an anisotropic tomography inversion algorithm assuming heterogeneous elliptic anisotropy, in order to reconstruct three kinds of tomograms: tomograms of maximum and minimum velocities, and of the direction of the symmetry axis. The distribution of maximum velocity matched core logging results better than that of the minimum velocity. The degree of anisotropy, defined by the normalized difference between maximum and minimum velocities, was helpful in deciding whether an anomalous zone in a tomogram was a cavity or not. By careful examination of borehole radar reflection and tomography images, the spatial distributions of cavities were delineated, and most of them were interpreted as being filled with clay and/or water. All the interpretation results implied that two faults imaged clearly by a DC resistivity survey were among the most important factors controlling the groundwater movement in the survey area, and therefore were closely related to the development of cavities. The method of reinforcement of the pier foundations was based on the interpretation results, and the results were confirmed when construction work was resumed.

• Korean Journal of Environment and Ecology
• /
• v.24 no.2
• /
• pp.108-116
• /
• 2010

This study was conducted to investigate the actual vegetation and Degree of Green Naturality(DGN) in Taeanhaean National Park in 2009. The actual vegetation of the surveyed site was classified into eleven plant communities and the others. Substitutional forest were classified into six plant communities; Pinus thunbergii community, P. densiflora community, Deciduous Broadleaf Forest, P. densiflora-Deciduous broadleaf Forest, etc. and the afforested lands were classified into five forest types: P. thunbergii, P. thunbergii-P. rigida Forest, Robinia pseudoacacia Forest, etc. The area of DGN 8 consisted of 40.66% while the area of DGN 9 consisted of 13.7% when compared with land area of Taeanhaean National Park. For the recovery of natural landscape and biological diversity of Taeanhaean National Park needs to be managed for eliminate to the exotic plants.

• International Journal of High-Rise Buildings
• /
• v.6 no.2
• /
• pp.165-175
• /
• 2017

The importance of designing urban building complexes so that they obtain 'urban' power, rather than become isolated from the surrounding urban context, has been well recognized by both researchers and practitioners. Nevertheless, most current discussions are made from architects' personal experiences and intuition, and lack a quantitative understanding, to which obstacles include an in-depth exploration of the 'urban' power between building complexes and the urban environment. This paper attempts to measure this feature of 'urban', i.e., 'urbanity,' through a new analytical approach derived from the opendata environment. Three measurements that can be easily collected though the Google Maps API and Open Street Map are applied herein to evaluate high or low values of urbanity. Specifically, these are 'metric depth', i.e., the scale of extended public space, 'development density', i.e., density and distribution of point of interests (POIs), and 'type diversity', i.e., diversity of different commercial types. Six cases located in Japan, China and Hong Kong respectively are ranked based on this analytical approach and compared with each other. It shows that Japanese cases, i.e., Osaka Station City and Namba Parks, Osaka, obtained clearly higher values than cases in Shanghai and Hong Kong. On one hand, the insight generated from measuring and explaining 'urban' power would help to assist better implementation of this feature in the design of urban building complexes. On the other hand, this analytical approach can be easily extended to achieve a large-scale measurement and comparison among different urban building complexes, which is also helpful for design practitioners.

• Nuclear Engineering and Technology
• /
• v.28 no.1
• /
• pp.44-55
• /
• 1996

For the purpose of controlling the release of radioiodine to the environment in nuclear power plants, adsorption characteristics of elemental iodine and methyl iodide on the base carbon and 2%, 5% TEDA impregnated carbons were studied. The amounts of adsorption of elemental iodine and methyl iodide on the carbons were compared with Langmuir, Freundlich, Sips and Dubinin-Astakhov(DA) isotherm equations. Adsorption data were well correlated by the DA equation based on the potential theory. Adsorption energy distributions were obtained from the parameters of the DA equation derived from the condensation approach method. For the adsorption of methyl iodide and elemental iodine-carbon system, the DA equation can be well expressed by the degree of heterogeneity of the micropore system because the surface is nonuniform when its potential energy is unequal. The adsorption energy distribution wes investigated to find a surface heterogeneity on the carbon. The surface heterogeneity for iodine-carbon system is highly affected by the adsorbate-adsorbent interaction as well as the pore structure. The surface heterogeneity increases as a content of TEDA impregnated increases. The adsorption nature of methyl iodide on carbon turned out to be more heterogeneous than that of elemental iodine.

• Journal of Welding and Joining
• /
• v.3 no.1
• /
• pp.22-31
• /
• 1985

Hot straining embrittlement is one of the most important factors which cause the brittle fracture initiation even in the service temperature in the case of mild steel and high tensile steel. Therefore it is necessary to analyze thoroughly the hot straining embrittlement occurred in weld HAZ of the structural steels. The behaviors of plastic deformation and fracture toughness at the notch tip of the hot strained weld HAZ in structural steels (SB 41 KS, SA 588-Grade A ASTM) have been studied by the recrystallization technique and crack opening displacement (COD) test method. The obtained results are summarized as follows; 1. The plastic zone is formed at the notch tip of weld HAZ owing to nomotonic and cyclic hot stran, and the maximum plastic strain increases with the accumulated hot straining amounts. 2. The distribution of the effective strain at the plastic deformed zone in HAZ can be determined as follows; (.epsilon. over bar $_{p}$ )$_{\chi}$=.epsilon. over bar $_{cr}$ ( $R_{/chi}$/.chi.)$^{m}$ where, .epsilon. over bar $_{cr}$ : (SB 41; .epsilon. over bar $_{cr}$ = 0.2, SA 588; .epsilon. over bar $_{cr}$ = 0.1) 3. The embrittlement of weld HAZ in SB 41 and SA 588 is influenced by hot strain, and the degree of embrittlement becomes deeper with hot straining amounts. 4. The embrittlement of weld HAZ of SB 41 is not influenced by the hot straining amounts until .epsilon. over bar $_{max}$ = 0.36, $R_{\chi}$ = 0.065mm, however the embrittlement of structure in SA 588 is considerably influenced even by a small quantity of the hot straining amounts.s.