• Geophysics and Geophysical Exploration
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• v.10 no.4
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• pp.332-344
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• 2007

Various geophysical well logs have been made along the four deep wells in Pohang, Gyeongbuk. The primary focus of geophysical well loggings was to improve understanding the subsurface geologic structure, to evaluate in situ physical properties, and to estimate aquifer production zones using fluid temperature and conductivity gradient logs. Especially natural gamma logs interpreted with core logs of borehole BH-1 were useful to discriminate the lithology and to determine the lithologic sequences and boundaries consisting of semi-consolidated Tertiary sediments and intrusive rocks such as basic dyke and Cretaceous sediments. Cross-plot of physical properties inferred from geophysical well logs were used to identify rock types such as Cretaceous sandstone and mudstone, Tertiary sediments, rhyolite, and basic dyke. The temperature log indicated $82.51^{\circ}C$ at the depth of 1,981.3 meters in borehole BH-4. However, considering the temperature of borehole BH-2 measured under stable condition, we expect the temperature at the depth in borehole BH-4, if it is measured in stable condition, to be about 5 or $6^{\circ}C$ higher. Several permeable fractures also have been identified from temperature and conductivity gradient logs, and cutting logs.

• Journal of the Korean Chemical Society
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• v.54 no.1
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• pp.105-109
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• 2010

HEMA (2-hydroxyethyl methacrylate), EGDMA (ethylene glycol dimethacrylate) and propylene glycol was copolymerized in the presence of AIBN (azobisisobutyronitrile) initiator in a mould. The physical properties of the contact lens were measured. The water content of 37.06~38.71%, refractive index of 1.492~1.432, visible transmittance of 89.4~91.5%, tensile strength of 0.1416~0.2302 kgf, and contact angle of $38.60{\sim}53.53^{\circ}$ were obtained. Therefore, the contact lens material produced using propylene glycol as an additive satisfied the basic physical properties required for contact lenses application. It is interesting to note that an increase in wettability and tensile strength while having no significant changes in water content.

• Carbon letters
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• v.4 no.2
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• pp.57-63
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• 2003

In polymer precursor based activated carbon, the structure of starting material is likely to have profound effect on the surface properties of end product. To investigate this aspect phenolic resins of different types were prepared using phenol, mcresol and formaldehyde as reactants and $Et_3N$ and $NH_4OH$ as catalyst. Out of these resins two resol resins PFR1 and CFR1 (prepared in excess of formaldehyde using $Et_3N$ as catalyst in the basic pH range) were used as raw materials for the preparation of activated carbons by both chemical and physical activation methods. In chemical activation process both the resins gave activated carbons with high surface areas i.e. 2384 and 2895 $m^2/g$, but pore size distribution in PFR1 resin calculated from Horvath-Kawazoe method, contributes mainly in micropore range i.e. 84.1~88.7 volume percent of pores was covered by micropores. Whereas CFR1 resin when activated with KOH for 2h time, a considerable amount (32.8%) of mesopores was introduced in activated carbon prepared. Physical activation with $CO_2$ leads to the formation of activated carbon with a wide range of surface area (503~1119 $m^2/g$) with both of these resins. The maximum pore volume percentage was obtained in 3-20 ${\AA}$ region by physical activation method.

• Carbon letters
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• v.5 no.4
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• pp.159-163
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• 2004

The polymer-ceramic hybrid, known as 'ceramer', was synthesized by a sol-gel process by incorporating different amount of alkoxide as source of silicon in resorcinol-formaldehyde in presence of basic catalyst to get different percentage of silicon in ultimate carbonized composites. FTIR of the ceramer confirms that it is a network of Si-O-Si, Si-O-$CH_2$ and Si-OH type groups linked with benzene ring. Different amount of silicon in the ceramer exhibits varying temperature of thermal stability and lower coefficient of thermal expansion as compared to pure resorcinol-formaldehyde resin. The lower value of CTE in ceramer is due to existence of silica and resorcinol -formaldehyde in co-continuous phase. Unidirectional composites prepared with ceramer matrix and high-strength carbon fibers show lower value of flexural strength at polymer stage as compared to those prepared with resorcinol-formaldehyde resin. However, after heat treatment to $1450^{\circ}C$, the ceramer matrix composites show large improvement in the mechanical properties, i.e. with 7% silicon in the ceramer, the flexural strength is enhanced by 100% and flexural modulus value by 40% as compared to that of pure resorcinol-formaldehyde resin matrix composites.

• Journal of Biomedical Engineering Research
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• v.18 no.3
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• pp.205-210
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• 1997

This is to investigate the physical properties of the commercially available Soft, Thomas, Minerva, and Philadelphia cervical braces which are widely used in orthopedics, neurosurgery, and rehabilitation medicine clinics as assisting devices for physical stabilization of cervical vertebrates, to use as a basic data for designing new type brace. Tensile strengths were observed by universal mechanical measuring device and Thomas brace required the highest stress to break by tensile stress. Durabilities against continuous frictional forces were also determined, and Minerva brace demonstrated the longest frictional time until being perforated. According to these results, poly ethlene is recommendable as a frame and preparation of pores in the material is favorable to provide ventilation to skin.

• Journal of muscle and joint health
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• v.29 no.1
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• pp.11-17
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• 2022

Purpose: This study aimed to provide objective and basic data for an effective treatment method by examining changes in the mechanical properties of muscles and the degree of tenderness when a combination of stretching exercise and ultrasound therapy is applied to patients with tension headaches. Methods: The participants were classified into two groups based on the intervention received: the therapeutic ultrasound combined with suboccipital stretching (n=15, experimental group) and infrared combined with suboccipital stretching (n=15, control group) groups. The intragroup differences in mechanical muscle properties and modified total tenderness score were compared and analyzed. Results: The comparison and analyses of the changes in muscle tone and stiffness revealed statistically significant intragroup decreases in the upper trapezius and suboccipitalis in the experimental group. Similarly, the comparison and analyses of the changes in muscle stiffness revealed statistically significant intragroup decreases in the upper trapezius in the control group. Conclusion: Therapeutic ultrasound combined with suboccipitalis stretching effectively increased the flexibility of the muscles around the cervical vertebrae and reduced muscle tension and stiffness in tension-type headache patients

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.48.1-48.1
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• 2021

The Main-belt asteroid (298) Baptistina (hereafter 'Baptistina') is regarded as an X- (or C-) type asteroid and the largest member of the Baptistina asteroid family. Its basic physical properties play an important role in understanding the rotational evolution and orbital dynamics of the Baptistina family. In this study, we determined the physical characteristics of Baptistina from the optical observations. We conducted BVRI and R band photometric observations from 2017 to 2021 for a total of 47 nights using the 0.5 - 2.0 m-class telescopes. As a result, the color indices of Baptistina were derived as, , and ; this result is consistent with the previous classification of Baptistina as an X- (or C-) type. We also determined absolute magnitude () and slope parameter () by using a simplified version of the IAU H & G function (Bowell et al. 1989) are mag and respectively. We calculated the effective radius of Baptistina of km considering the visual geometric albedo of 0.131 from the NEOWISE data. Using the light-curve inversion method, the sidereal rotation period of 16.224235 h and the 3D shape model with a pole orientation (,) were also determined. In this presentation we will introduce our observations and results, and also discuss about the physical properties of Baptistina asteroid family members such as color indices.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.146-147
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• 2021

An increase in carbon emissions leads to the problem of global warming and is an issue to be solved in other countries. The problem of carbon dioxide has many effects not only on global warming but also on people. According to the World Health Organization (WHO), 4.3 million people have died because harmful substances generated indoors cannot be discharged to the outside and accumulate in the human body through the respiratory tract. In response to this situation, in order to reduce the generation of pollutants in the building itself, soak into lightweight bubble concrete to adsorb and purify indoor pollutants, mix charcoal, investigate the appropriate amount and physical characteristics, and check carbon dioxide This is an experiment for grasping the adsorption capacity, and the results are as follows. As the replacement rate of rice husk charcoal increased, the compressive strength tended to decrease, and the carbon dioxide reduction rate tended to increase. It is judged that the charcoal of rice husks shows a low density and the physical adsorption is smooth due to the porous structure. Since it is excellent in the basic physical properties and carbon dioxide adsorption surface of this experiment, it is judged that it has sufficient potential for use as an indoor finishing material.

• Advances in nano research
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• v.14 no.6
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• pp.541-555
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• 2023

The extensive use of polymeric matrix composites in the athletic sector may be attributed to its high strength-to-weight ratio, production economy, and a longer lifespan than conventional materials. This study explored the impact of carbon nanotubes on the properties of different composite field sports equipment components. The test specimens were fabricated using the compression molding technique. The insertion of carbon nanotubes increases mechanical properties related to the process parameters to account for an improvement in the stick sections' overall performance. The dynamic response of functionally graded reinforced nanocomposite wire structure is examined in this paper on the bases of high-order hyperbolic beam theory lined to the size-dependent nonclassical nonlocal theory under the external mechanical load due to the physical activities. Finally, the impact of different parameters on the stability of nanocomposite structures is discussed in detail.

• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2367-2374
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• 2013

Lysine (Lys) immobilized on zeolite 4A was prepared by a simple adsorption method. The physical and chemical properties of Lys/zeolite 4A were investigated by X-ray diffraction (XRD), FT-IR, Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-vis. The obtained organic-inorganic composite was effectively employed as a heterogeneous basic catalyst for synthesis of ${\alpha},{\beta}$-unsaturated carbonyl compounds. No by-product formation, high yields, short reaction times, mild reaction conditions, operational simplicity with reusability of the catalyst are the salient features of the present catalyst.