• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.4
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• pp.613-618
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• 2009

Impacted molars are not usual with the prevalence rate of less than 1%, however problems such as infraocclusion, extrusion of the opposite tooth and lack of space are caused. If molars are impacted, radiographic check-up and observations are needed as they play an important role in skeletal development and mastication. Causes of impaction are underdevelopment of roots, supernumerary teeth, cysts, odontomas, ankylosis and etc. In our first case, we present impacted molar which was surgically exposed and orthodontically traded. As the developmental state of the root was less than half at first visit, we observed until the root was 2/3 in its length and traction was carried out. The second case is orthodontic traded molar with compleate enucleation of the existing cysts. When trading impacted molars, direct bonding of attachments to the tooth and light continuous forces are recommended so as to ankylosis, external absorption and periodontal attachment loss avoid. Fixed appliances tract the teeth on arch and obtain eruption spaces without patient's cooperation. We report surgically exposed and orthodontically traded molars which resulted in good occlusion and patients satisfaction.

• Korean Parent-Child Health Journal
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• v.4 no.1
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• pp.1-18
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• 2001

Fatigue after delivery affect women's birth experience and interrupt the process of labor. Finally woman cannot have a positive birth result and will experience a postpartum fatigue. But researches about fatigue during the labor are lacked. Nurse help adapting a mother's role, bonding with new baby, recovering after birth, and improving woman's quality of life through decreasing fatigue during the labor and intercepting a continued postpartum fatigue. So it is very important that measuring a fatigue and confirming relationships between fatigue and factors affecting fatigue. The purpose of this study was measuring the level of fatigue within 4hours after delivery and identifing factors affecting fatigue. The ultimate goal was to contribute to improving a birth experience and adapting after birth through decreasing the level of fatigue and interventions. The data was collected for this study at the hospital of two universities and the third hospital in Seoul from Aug. 15. to Nov. 10. 2000. The subjects were 106 of mothers who deliveried a normal newborn and were tested within four hours after birth. The instruments were The Visual Analogue Scale for fatigue, The State Anxiety Inventory, and The Labor Support Inventory. The data were analyzed by using percentage, mean, SD, t-test, ANOVA, Pearson correlation. The results of this study were as follows; (1) The level of fatigue during the labor was 61.48point. (2) The deferences according to general and obstetric character affecting fatigue founded that there were Significant differences according to job(t=2.659, p=0.009), and the type of delivery(t=-2.035, p=0.044). (3) The deferences according to factors affecting fatigue revealed that there was significant difference according to quality of sleep(F=2.935, p=0.037). The significant fatigue and the fatigue after delivery was anxiety(r=0.343, p=0.000). The above findings indicate that the level of fatigue during the labor is higher than during pregnancy and postpartum. Woman having a job, delivering by vacuum was more fatigued. The level of fatigue according to a quality of sleep was significant difference. The poor quality of sleep, higher level of fatigue. And the more anxiety after delivery, the more fatigue. So, the variable nursing interventions for lessening the level of fatigue through appling the situation for rest, relaxation during the labor to reserve energy, and decreasing anxiety should be provided for mothers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.6788-6798
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• 2015

In recent high speed rail way, the operating speed of train is enhanced and the introduction of EMU train vehicles is increased. In addition, as expected the demand of the concrete slab track and the trend of design cross-section reduction, the clear behavior of evaluation of internal slab layer is demanded about the variation of design load and speed. The purpose of this study is to evaluate and identify the mechanical behavior pattern of concrete slab track and track-road bed with the variation of axle load and train speed. To this end, the behavior of TCL and HSB was evaluated in according to the variation of axle load and speed. And the analysis results and the data measured TCL strain sensor, which was embedded in TCL slab under installation on Honam high speed railway, was analyzed. The analysis result shows that the strain are increasing in according to the speed-up of train, and line regression was obtained from measured data. Analysis data of the state of bonding condition of slab layer and measured data was analyzed. It is conducted that the TCL layer stress of HEMU 430X, which of axle load, is lighter was similar to the stress of KTX-Honam, the standard deviation of measured stress is dramatically increased.

• Journal of the Korean institute of surface engineering
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• v.42 no.1
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• pp.8-12
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• 2009

Electronic structures and chemical bonding of Li-intercalated $LiTiS_2$ and $LiTiO_2$ were investigated by using discrete variational $X{\alpha}$ method as a first-principles molecular-orbital method. ${\alpha}-NaFeO_2$ structure is the equilibrium structure for $LiCoO_2$, which is widely used as a commercial cathode material for lithium secondary battery. The study especially focused on the charge state of Li ions and the magnitude of covalency around Li ions. The average voltage of lithium intercalation was calculated using pseudopotential method and the average intercalation voltage of $LiTiO_2$ was higher than that of $LiTiS_2$. It can be explained by the differences in Mulliken charge of lithium and the bond overlap population between the intercalated Li ions and anions in $LiTiO_2$ as well as $LiTiS_2$. The Mulliken charge, which means the ionicity of Li atom, was approximately 0.12 in $LiTiS_2$ and the bond overlap population (BOP) indicating the covalency between Ti and S was about 0.339. One the other hands, the Mulliken charge of lithium was about 0.79, which means that Li is fully ionized. The BOP, the covalency between Ti and O, was 0.181 in $LiTiO_2$. Because of high ionicity of Li and the weak covalency between Ti and the nearest anion, $LiTiO_2$ has a higher intercalation voltage than that of $LiTiS_2$.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.835-841
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• 2013

Modern solid-state gyroscopes (HRG) with hemispherical resonators from high-purity quartz glass and special surface superfinishing and ultrathin gold coating become the best instruments for precise-grade inertial reference units (IRU) targeting long-term space missions. Designing of these sensors could be a notable contribution into development of Korea as a space nation. In participial, 40mm diameter thin-shell resonator from high-purity fused quartz, fabricated as a single-piece with its supporting stem has been designed, machined, etched, tuned, tested, and delivered by STM Co. (ATS of Ukraine) several years ago; an extremely-high Q-factor (upto 10~20 millions) has been shown. Understanding of the best way how to match such a unique sensor with inner glass assembly of the gyro means how to use the high potential in a maximal extent; and this has become the urgent task. Inner quartz glass assembly has a very thin indium (In) layer soldered the resonator and its silica base (case), but effects of internal resonances between operational modal pair of the shell-cup and its side (parasitic) modes can notable degrade the potential of the sensor as a whole, instead of so low level of resonator's intrinsic losses. Unfortunately, there are special combinations of dimensions of the parts (so-called, "resonant sizes"), when intensive losses of energy occurs. The authors proposed to use the length of stem's fixture as an additional design parameter to avoid such cases. So-called, a cyclic scheme of finite element method (FEM) and ANSYS software were employed to estimate different combinations of gyro assembly parameters. This variant has no mismatches of numerical origin due to FEM's discrete mesh. The optimum length and dangerous "resonant lengths" have been found. The special attention has been paid to analyses of 3D effects in a cup-stem transient zone, including determination of a difference between the positions of geometrical Pole of the resonant hemisphere and of its "dynamical Pole", i.e., its real zone of oscillation node. Boundary effects between the shell (cup) and 3D short "beams" (inner and outer stems) have been ranged. The results of the numerical experiments have been compared with the classic model of a quasi-hemispherical shell band with inextensional midsurface, and the solution using Rayleigh's functions of the $1^{st}$ and $2^{nd}$ kinds. To guarantee the truth of the recommended sizes to a designer of the real device, the analytical and FEM results have been compared with experimental data for a party of real resonators. The consistency of the results obtained by different means has been shown with errors less than 5%. The results notably differ from the data published earlier by different researchers.

• Journal of the Korean Wood Science and Technology
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• v.35 no.6
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• pp.100-107
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• 2007

People have spent lots of time inside building about 90% of these day. Industry has been developed rapidly after I960. Construction materials had changed from natural materials to chemical materials and confidentiality of building has been more higher than before by policy of saving energy. These have caused sick-building syndrome (SBS) for us. So people want environmental construction materials for their house. We designed a environmental loess (yellow soil) finishing material which was composed of loess, water, water-soluble resin, hardener and filler. The purposes of this study were that making an environmental loess finishing material with optimum ratio, evaluating the usability of loess finishing material for wall. Furthermore it was suitable for wall to evaluate mechanical properties that are impact test, cracking test, abrasion test and de-bonding test, environmental properties that were emission of VOCs, formaldehyde and far infrared radiation.

• Polymer(Korea)
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• v.25 no.2
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• pp.186-198
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• 2001

pH/Thermal sensitive copolymers with the various acidic comonomer compositions composed of N-isopropylacrylamide (NIPAAm) with acrylic acid (AAc), 2-acrylamido glycolic acid (AAmGAc), and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) were synthesized by free radial polymerization. In this study, to characterize the effect of different acidic comonomer composition and pH on the lower critical solution temperature (LCST) behaviors of their copolymers. phase transition experiments were performed with a thermo-optical analyzer (TOA). The phase transition temperature (T$^{p}$ ) of aqueous poly(NIPAAm-co-AAc) solution was lowered with increasing the ionization of the acid group in AAc, that is, the ionized state induced the electrostatic repulsion of ionized groups. In contrast, when AAmGAc was introduced into PNIPAAm, T$^{p}$ was little changed at pH 1-3, whereas climbed up significantly from pH 1 to pH 3. In the range of pH 6-10, Tp was lower than that of pH 3-5. This result was considered to be \"Ionic Screen Effect\" and this effect had been also observed in the case of poly(NIPAAm-co-AMPS).-co-AMPS).

• Nuclear Engineering and Technology
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• v.13 no.3
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• pp.145-152
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• 1981

Even though a lately reported method of high temperature exchange labelling of o-iodo-hippuric acid (Hippuran) in the absence of oxidizing agent was considered to be an attractive one, the exchange mechanism was somewhat unclear. In this study iodine isotope exchanges between o-iodohippuric acid (OIH) and radioiodide ($^{125}$ $I^{ }$) or between OIH and molecular radioiodine ($^{125}$ $I_2$) were carried out at two different temperatures. Rate constants and activation parameters were measured by applying a radio-paper chromatography technique. Since o-iodobenzoic acid is known as a by-product in the exchange labelling of OIH, data were also obtained for the OIB-iodide systems for comparison. The rate constant was increased in the order of OIB...$^{125}$ $I^{[-10]}$ >OIB...$^{125}$ $I_2$>OIH..$^{125}$ $I^{[-10]}$ >OIH...$^{125}$ $I_2$ and the activation parameters for OIH were generally larger than those for OIB :$\Delta$H$\neq$$_{OIH}$>$\Delta$H$\neq$$_{OIB}$, $\Delta$S$\neq$$_{OIH}$>$\Delta$S$\neq$$_{OIB}$. These results suggest that the mechanism of the high temperature exchange is predominantly nucleophilic even though some electrophilic character can also be involved depending upon reaction conditions. Such a fact may well be caused by a feasible formation of hydrogen bonding type transition state due probably to the ortho substituent effect of-CONHC $H_2$COOH. Thus, the high temperature exchange method is estimated to be quite effective for labelling Hippuran especially at a small research center where reducing agent-free $^{131}$ I is unavailable.ailable..

• International Journal of Highway Engineering
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• v.12 no.4
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• pp.101-110
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• 2010

In this paper, it has been studied about the CRCO to maintain or rehabilitate the aged JCP. The CRCO and JCO was constructed at useless section of Seo-Hae-Ahn express highway in South Korea. The performance evaluation was conducted. Especially, it was focused on the roll of longitudinal reinforced steels inserted into the CRCO. On crack survey results from field construction section, the reflection cracks at joint of the existing pavement occurred in CRCO. However, due to the constraints of longitudinal reinforced steels, crack width was small. Total crack length and quantity in the CRCO more than that in the JCO. And crack spacing in the CRCO was narrower than it in the CRCP. Through the bonding strength test results, if the cold milling and cleaning as well as surface treatment is applied, there will be no debonding problem at interlayer in the early age. From analysis of the horizontal behavior at the joint, the longitudinal reinforced steels constrained crack width which became wider than initial state over time. Also, that steel in the CRCO reduced the horizontal movement due to temperature variation(4 times than that in the JCO). But, if interface is debonded, the roll decreased. Vertical VWG data showed that CRCO did not occur debonding problem at steel location, but there was some problem in JCO. It was confirmed by field coring. The tensile strain appeared in the CRCO, But the compressive strain occurred in the JCO in early age. Through the FWD test result, deflection in the CRCO was less than that in the JCO. And K value in the CRCO was greater than it in the JCO.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.299-305
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• 2019

As the damage factors of the three­storey stone pagoda of the Bulguksa Temple in Gyeongju could cause a reduction in the historical and artistic value and accelerate the deterioration of the stone, an appropriate solution is needed. The aim of stone conservation is to conserve the original shape and convey originality from the ancestors to their descendants. This procedure includes a record of the condition, being available in the future. In particular, the damage assessment could be used in conservational research, educational data, conservational treatment, and preventive data. As a result of quantitative damage assessment, biological damage indicated 159 %, chemical damage 114 %, and physical damage 16 %. The west direction revealed 95 % because of the amount of sunshine, moisture, and expansion of rock. Complex factors and high range damage were observed on the foundation and body of the pagoda. Since the top of pagoda was restored in the 1970s, the state presented a good condition. By doing this, the number of organisms could be reduced by cleaning and the physical damage could be minimized by bonding. On the other hand, continuous monitoring will be needed because there is a possibility of reforming the damage in the future.