• Proceedings of the Korean Geotechical Society Conference
• /
• 1999.10a
• /
• pp.217-223
• /
• 1999

Mostly, water leakage took place in construction joints. In case of cable tunnels constructed by open-cut method, waterstops have been used to prevent the water leakage. But, we haven't any experience to install the waterstops in NATM cable tunnels. So, it is necessary to develope the waterstops and test the performance of it in laboratory. We manufactured cable tunnel lining quarter scale model by pouring concrete, and installed the waterstops. After filling the inside of concrete lining about two-third with water, we put the air pressure on the water, In addition, it is also carried out water leakage test for concrete lining model without waterstops. As a result, we confirmed the performance of waterstops and its adaptability. It is also tested that the performance of rubber gaskets used in concrete segments of Shield tunnelling. In addition, we determined the allowable infiltration rate for cable tunnel with non-drainage system.

• 한국태양에너지학회:학술대회논문집
• /
• 2008.04a
• /
• pp.324-329
• /
• 2008

Recently with the demand of well-being is increased, the demand for indoor thermal environment and air quality is increased. According to this circumstance, many people in Korea note the traditional architecture that is made by natural materials, such as a soil, stone and wood. However, few researches regarding the indoor thermal environmental characteristics of the Korean traditional houses is reported. In this study we analyzed the indoor thermal environment for Han-ok through field measurement. Moreover, based on the field measurement results. indoor thermal comfort in Han-ok is analyzed.

• Proceedings of the KSR Conference
• /
• 2007.05a
• /
• pp.1760-1769
• /
• 2007

The cut slope sliding which has been frequently encountered in Pohang area has been reported due to the rapid reduction of shear strength in mudstone after being exposed to the air. Mudstone has characteristics that it has high enough strength and stiffness in a dry condition, but the strength and stiffness decrease in a wet condition with groundwater infiltration. The case study in this paper shows that mudstone which had enough strength in a boring stage has lost the strength after installing PRD steel pipe pile inducing an insufficient bearing capacity, which has been ascertained by the static load test. Test construction has been performed to investigate the most favorable method for increasing a pile bearing capacity in mudstone with various methods such as MSG (Micro Silica Grouting) around the tip and side of a pile, the perimeter grouting combined with Micro pile reinforcement, and concrete filling after tip reinforcing grouting. From the test construction, MSG has been turned out to be the most favorable method for increasing a pile bearing capacity in mudstone, which has been confirmed by the static load test.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.45 no.4
• /
• pp.107-114
• /
• 2003

This study was performed to develop the plantable concrete block using rice straw ash and apply for inclined plane. For the planting, plantable concrete block needs infiltration of water and air through void of block. The materials used for plantable concrete block are cement, rice straw ash, and coarse aggregate (5-10, 10-20 mm). Plantable block size is $23\times23\times4$ cm, and species of planting are Tall fescue, Lespedeza cyrtobotrya and Lespedeza cuneata. At the 6 months after seeding, germination ratio and grown-up length of Tall fescue, Lespedeza cyrtobotrya and Lespedeza cuneata are shown in 90%, 60%, 50%, and 40~50 cm, 90~120 cm, 60~75 cm, respectively.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2006.09a
• /
• pp.374-375
• /
• 2006

Three-dimensional artificial crystals with periodicity corresponding to terahertz wave lengths were fabricated by self-assembling monosized metal spherical particles. The metal crystals were weakly sintered to utilize them as templates. The metal templates were inverted to air spheres crystal embedded in dielectric resin though infiltration and etching. The resulting resin inverted crystals clearly presented the photonic stop gaps within terahertz wave region and the frequencies of the gaps were confirmed to agree well with calculation by plane wave expansion method.

• Archives of Craniofacial Surgery
• /
• v.20 no.3
• /
• pp.199-202
• /
• 2019

Traumatic subcutaneous emphysema, which is the infiltration of air into subcutaneous tissues due to trauma, is caused by various factors such as chest and/or abdominal trauma, facial fractures, and barotrauma caused by mechanical ventilation. In this case report, a 32-year-old woman developed traumatic subcutaneous emphysema after undergoing abdominal liposuction at a local clinic. She was subsequently admitted to Busan Paik Hospital, and with early diagnosis and conservative treatment, she was discharged on the seventh day of hospitalization with no complications. However, because traumatic subcutaneous emphysema may accompany other injuries for various reasons, radiological examination and various tests should be performed to prevent serious complications and sequelae.

• Food Science and Preservation
• /
• v.16 no.2
• /
• pp.253-258
• /
• 2009

This study investigated the effects of mycelium and culture supernatant of Cordyceps ochraceostromat(Co) on air way hyper-responsiveness, pulmonary immune cell infiltration, and Th2 cytokine expression in animal models of atopy and asthma. After ConA(+/-) activation of mouse primary spleen cells, decreased IL-4 and IL-13 cytokine production were seen in the presence of Co mycelium extracts and culture supernatant. The asthma model involved mice sensitized to ovalbumin by i.p. injection treatment; Co mycelium extract was also injected. The atopy model was the dinitrofenylbenzene-treated mouse ear. Ear thicken ing induced by DNFB was decreased by Co mycelium extract, and the extract also inhibited lung cell infiltration in ovalbumin-induced asthmatic mice. The results thus indicated that the Co mycelial extract reduced the undesirable immune responses seen in asthma and atopy.

• Composites Research
• /
• v.26 no.5
• /
• pp.322-327
• /
• 2013

Carbon fiber-reinforced SiC matrix composites have good oxidation resistance and thermal shock resistance. These properties have allowed the composites to be applied to high-temperature structures. In this study, $C_f/SiC$ composites were fabricated via precursor infiltration and pyrolysis (PIP) process, including liquid phase infiltration and chemical vapor curing using cyclohexene. The final $C_f/SiC$ composites, which have gone through the PIP process five times, showed a density of $1.79g/cm^3$, as compared to a density of $0.43g/cm^3$ for pre-densified bare carbon fiber preform. As for the oxidation resistance characteristics, the weight of $C_f/SiC$ composite was maintained at 81% at $1400^{\circ}C$ in air for 6 hours. Chemical vapor curing (CVC) using cyclohexene has shown to be an effective method to achieve high densification, leading to increased oxidation resistance.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.12
• /
• pp.3593-3599
• /
• 2010

In an original effort, this lab attempted to employ polystyrene nanoparticles as a template for the synthesis of ordered and highly porous macroporous $SiO_2$ thin films, utilizing their high combustion temperature and narrow size distribution. However, polystyrene nanoparticle thin films were not obtained due to the low interaction between individual particles and between the particle and silicon substrate. However, polystyrene-polyacrylic acid (PS-AA) colloidal particles of a core-shell structure were synthesized by a one-pot miniemulsion polymerization approach, with hydrophilic polyacrylic acid tails on the particle surface that improved interaction between individual particles and between the particle and silicon substrate. The PS-AA thin films were spin-coated in the thickness ranges from monolayer to approximately $1.0\;{\mu}m$. Using the PS-AA thin films as sacrificial templates, macroporous $SiO_2$ thin films were successfully synthesized by vapor deposition or conventional solution sol-gel infiltration methods. Inspection with field emission scanning electron microscopy (FE-SEM) showed that the macroporous $SiO_2$ thin films consist of interconnected air balls (~100 nm). Typical macroporous $SiO_2$ thin films showed ultralow refractive indices ranging from 1.098 to 1.138 at 633 nm, according to the infiltration conditions, which were confirmed by spectroscopy ellipsometry (SE) measurements. This research shows how the synthetic control of the macromolecule such as hydrophilic polystyrene nanopaticles and silicate sol precursors innovates the optical properties and processabilities for actual applications.

• Journal of Environmental Health Sciences
• /
• v.27 no.2
• /
• pp.145-152
• /
• 2001

The purpose of this study was to determine nitrogen dioxide(NO$_2$) decay rate by reaction between NO$_2$ and interior materials in Korean residence. The results of this research could be helpful to choose the interior construction materials and to study on reduction of indoor air pollutants. The results of this research are as follows; For 30 residences in Seoul and Incheon from October 2000 to march 2001, the mean of infiltration rate was 0.70$\pm$0.44 ACH, and single-detached houses (7 houses) and apartments (19 houses) were 0.97$\pm$0.55 ACH and 0.61$\pm$0.34 ACH, respectively. The $CO_2$ decay followed approximately first-order process ($R^2$=0.97$\pm$0.02). There existed a statistic significance in filtration rate between houses built in 1980’s and built in 1990’s by t-test (p<0.02). Mean of NO$_2$ decay rates in 26 residence3s except 4 residences was 0.94$\pm$0.49hr$^{-1}$ , and also 0.86$\pm$0.49hr$^{-1}$ , 0.97$\pm$0.50hr$^{-1}$ in single-detached houses and apartments, respectively. Mean NO$_2$ decay rates in houses built in 1980’s were 0.78$\pm$0.37hr$^{-1}$ , 1.33$\pm$1.03hr$^{-1}$ , respectively. Nothing were showed statistical significance among indoor temperature, indoor humidity, and NO$_2$ decay rate. However, NO$_2$ decay rates had a tendency to increase by increase of temperature and humidity. Average volume/surface of participated houses was 0.55$\pm$0.07m and mean NO$_2$ deposition velocity was calculated as 1.46$\pm$0.59msec$^{-1}$ .