• Journal of the Korean GEO-environmental Society
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• v.5 no.3
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• pp.51-60
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• 2004

In Korea there are recently many attempts to expand a temporary soil nailing system into a permanent soil nailing system since the first construction in 1993. In the soil nailing system, the rigid facing walls act on restraining the deformation of the ground. These are purposed to minimize the damage of adjacent buildings or underground structures. In Korea, to minimize the relaxation of the ground, the soil nailing system in the downtown area is often used experientially together with braced cuts, sheet pile walls, soil cement walls (SCW), or jet grouting walls. However, for the conservative design, the confining effects by the stiff facing have been ignored because the proper design approach of considering the facing stiffness has not been proposed. In this study, various laboratory model tests are carried out to examining the influence the rigidity of facings on the global safety of soil nailing system. Also, the parametric studies using the numerical technique as shear-strength reduction technique are carried out. In the parametric study, the thickness of concrete facing walls is changed to identify the effects of the facing wall stiffness.

• Journal of the Korean GEO-environmental Society
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• v.17 no.11
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• pp.45-53
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• 2016

A precast panel wall system resists against the horizontal earth pressure by increasing the shear strength of ground by reinforcement connected to the panel. The application of precast panel wall system is growing to lately minimize the earth work and environmental damage caused by large cut slope and to use the limited land effectively. The ground adhered panel wall system is the construction method that has the panel engraved with natural rock shape to improve the landscape. This system is developed to complete Top-Down method, and it is possible to have vertical cut, and to adhere to in-situ ground, improve construction ability by minimizing the ground relaxation and exclusion the trench and backfill process. In this study the field tests were performed to verify the construction ability about the vertical cut and complete Top-Down process and the construction behavior of ground adhered panel wall system was analyzed by large scale loading test and measurement results during loading test.

• Herbal Formula Science
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• v.21 no.1
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• pp.119-130
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• 2013

Objectives : Diabetes mellitus is the leading cause for vascular complications such as atherosclerosis. The present study is to investigate whether Doinseunggi-tang (DST) improves diabetic vascular dysfunction in type II diabetes. Methods : The db/db mice were treated with high fat/high cholesterol diet and DST (200 mg/kg/day) for 8 weeks. Results : DST significantly lowered blood glucose and systolic blood pressure. In addition, DST also markedly decreased total plasma cholesterol, triglyceride, and LDL-cholesterol, whereas increased the HDL-cholesterol. Vascular relaxation of aortic rings by acetylcholine or SNP was ameliorated by DST in a dose-dependent manner. Damage of vascular intima and hypertrophic of media was improved by DST. Immunohistological study revealed that DST attenuated the increase of ICAM-1, VCAM-1, and ET-1 expression in thoracic aorta. Conclusions : Taken together, DST suppressed hyperglycemia and diabetic vascular dysfunction in type II db/db mice. The present data suggests that Doinseunggi-tang may be prevent a development of diabetic atherosclerosis.

• Journal of Plant Biology
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• v.36 no.2
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• pp.133-140
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• 1993

The photosynthetic activities in relation to oxygen evolution rates, quantum yield, CO2 uptake rates and room temperature chlorophyll fluorescence were investigated in cotyledons of cucumber seedlings exposed to low temperature (at 4$^{\circ}C$) for 24 h. Light-chilling caused more inhibition on light-saturated maximum oxygen evolution rates, quantum yield, and CO2 uptake rates than dark-chilling did in the cucumber plant. Light-chilling induced more marked increase in Fo and decrease in (Fv)m/Fm than dark-chilling did in the room temperature chlorophyll induction kinetics. The above results affected by chilling in the light are considered to be associated with the partial damage of the reaction center of PS II and the decreased photosynthetic activities. There occurred a large decrease in qQ with little change in qNP in the light-chilling plant. When light- and dark-chilled plants were recovered at room temperature for 24 h and their chlorophyll fluorescences were induced with light doubling technique, light-chilled plants showed more smaller magnitude and rate of fluorescence relaxation than dark-chilled plants. These suggest that light-chilling might cause some alterations in transthylakoid pH formation, and that photosynthetic apparatus of cucumber cotyledons is more susceptible to light-chilling. In the fast fluorescence induction kinetics, FR was decreased by 60% in the light-chilled plants with reference to $25^{\circ}C$ light-grown plants, while the dark-chilled plants showed a decreased rate of only 20% with reference to $25^{\circ}C$ dark-treated plants for 24 h, indicating that cucumber seedling is very sensitive to chilling stress. So, it is certain that chilling injury to the photosynthetic apparatus is strongly dependent on the presence of light in cucumber seedlings.

• Journal of the Korean Society of Safety
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• v.35 no.5
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• pp.106-114
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• 2020

The two major trends that have emerged in recent years in relation to disaster recovery and recovery are 'regional infrastructure', 'regional leadership' and 'community recovery'. In the former case, it is to avoid disaster recovery and recovery by using external personnel and resources, and to maximize the resources in the area under the initiative of the residents of the affected area. And through this process, it is to prepare a new growth engine for disaster-affected areas. In addition, the latter expands disaster recovery targets to the general population living in affected areas and is not limited to victims. Through this, we can expect to recover the 'community' beyond the individual's recovery. In the Ansan of Gyeonggi-do, where many families of 'Sewolho' live, and in the Heunghae-eup of Pohang, Gyeongbuk-do, where the damage was severe, projects are underway to restore communities. And In these areas local activists and civic groups are actively utilized to efforts are being made to increase efficiency. Nevertheless, in the case of the community recovery program being promoted in Korea, there are limitations that it can be promoted only on the basis of special laws and that participation of various actors is necessary. This study intends to propose the limitations of current projects and ways to solve them by analyzing domestic and foreign cases related to the community recovery program for disaster-affected communities using local resources. we suggest two way. One is the relaxation of the national dependence of the community recovery program, and the other is to expand the area of disaster relief through.

• The Journal of Korean Physical Therapy
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• v.31 no.5
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• pp.266-272
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• 2019

Purpose: This study compared the effects of Static stretching and Mulligan's Two-leg rotation about the Hamstring flexibility, Hip range of motion, and pain. Methods: The subjects were allocated randomly into two groups: Static stretching group (n=13) and Mulligan's two leg rotation group (n=14). The study was designed with stretching protocols for four minutes and thirty seconds per day five times a week for three weeks in total. Measurements, including the Sit and reach test, Active/Passive Straight leg raise, and Visual analogue scale, were conducted before and after the intervention. The data were analyzed using a paired t-test and independent t-test. Results: The flexibility of the two leg rotation group was higher than the static stretching group after the intervention. The post-sit and reach test value of the two leg rotation group was significantly higher than the pre-sit and reach test value of the static stretching group. In addition, the variance of the sit and reach test of the two leg rotation group was significantly higher than that of the static stretching group. Conclusion: These results showed that two leg rotation techniques have a positive effect on the changes in the sit and reach test and active straight leg raise test. Two leg rotation techniques can be recommended as a self-stretching and easier way to stabilize the lumbopelvic rhythm, reduce the stiffness of the muscle and relieve pain. This is effective in preventing muscle damage, enabling muscle relaxation and reducing the risk of injury to the spine during daily lives and in sports activities.

• Journal of environmental and Sanitary engineering
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• v.7 no.2
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• pp.95-110
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• 1992

Much progress has been made in understanding the subcellular events of the human lung injuries after acute exposure to environmental air pollutants. Host of those events represent oxidative damages mediated by reactive oxygen species such as superoxide, hydrogen peroxide, and the hydroxy, free radical. Recently, nitric oxide (NO) was found to be endogenously produced by endothelial cells and cells of the reticulo-endothelial system as endothelialderived relaxation factor (EDRF) which is a vasoactive and neurotransmitter substance. Together with superoxide, NO can form another strong oxidant, peroxonitrite. The relative importance of exogenous sources of $N0/N0_2$ and endogenous production of NO by the EDRF producing enzymes in the oxidative stresses to the heman lung has to be elucidated. The exact events leading to chronic irreversible damage are still yet to be known. From chronic exposure to oxidant gases, progressive epithelial and interstitial damages develop. Type I epithelial cells become thicker and cover a smaller average alveolar surface area while thee II cells proliferate instead. Under acute damages, the extent of loss of the alveolar epithelial cell lining, especially type II cells appears to be a good predictor of the ensuing irreversible damage to alveolar compartment. Interstitial matrix undergo remodeling during chronic exposure with increased collagen fibers and interstitial fibroblasts. However, Inany of these changes can be reversed after cessation of exposure. Among chronic lung injuries, genetic damages and repair responses received particular attention in view of the known increased lung cancer risks from exposure to several air pollutants. Heavy metals from foundry emission, automobile traffics, and total suspended particulate, especially polycystic aromatic hydrocarbons have been positively linked with the development of lung cancer. Asbestos in another air pollutant with known risk of lung cancer and mesothelioma, but asbestos fibers are nonauthentic in most bioassays. Studies using the electron spin resonance spin trapping method show that the presence of iron in asbestos accelerates the production of the hydroxy, radical in vitro. Interactions of these reactive oxygen species with particular cellular components and disruption of cell defense mechanisms still await further studies to elucidate the carcinogenic potential of asbestos fibers of different size and chemical composition. The distribution of inhaled pollutants and the magnitude of their eventual effects on the respiratory tract are determined by pollutant-independent physical factors such as anatomy of the respiratory tract and level and pattern of breathing, as well as by pollutant-specific phyco-chemical factors such as the reactivity, solubility, and diffusivity of the foreign gas in mucus, blood and tissue. Many of these individual factors determining dose can be quantified in vitro. However, mathematical models based on these factors should be validated for its integrity by using data from intact human lungs.

• Journal of the Korea Concrete Institute
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• v.14 no.3
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• pp.382-391
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• 2002

This study is devoted to the problems of thermal and shrinkage stresses in order to avoid cracking at early ages. The early-age damage induced by volume change has great influence on the long-term structural performance of the concrete structures such as its durability and serviceability To solve this complex problem, the computer programs for analysis of thermal and shrinkage stresses were developed. In these procedures, numerous material models are needed and the realistic numerical models have been developed and validated by comparison with relevant experimental results in order to solve practical problems. A framework has been established for formulation of material models and analysis with 3-D finite element method. After the analysis of the temperature, moisture and degree of hydration field in hardening concrete structure, the stress development is determined by incremental structural formulation derived from the principle of virtual work. In this study, the stress development is related to thermal and shrinkage deformation, and resulting stress relaxation due to the effect of early-age creep. From the experimental and numerical results it is found that the early-age creep p)ays important role in evaluating the accurate stress state. The developed analysis program can be efficiently utilized as a useful tool to evaluate the thermal and shrinkage stresses and to find measures for avoiding detrimental cracking of concrete structures at early ages.

• Korean Journal of Optics and Photonics
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• v.13 no.4
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• pp.356-362
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• 2002

The molecular orientational dynamics of the nonlinear optical(NLO) side-chain polymer N-(4-nitrophenyl)-(L)-prolinol-poly (pphenylene terephthalates) have been studied using nonlinear optical responses as measured by second harmonic generation (SHG). A new pulsed corona poling is used to orient the NLO chromophores and the polymer segments into the noncentrosymmetric structure required to obtain the SHG signal. By corona poling of negative high voltage pulses with variable repetition rates (between 0.5 and 10 ㎑) at temperature between 25$^{\circ}C$ and 80$^{\circ}C$, well below and about the glass transition temperature 70$^{\circ}C$, the side-chain chromophores and the polymer chain contour rearrange themselves and create the domain structure observed by atomic force microscopy(AFM). The pulsed corona voltage enhances the orientational ordering of the NLO chromophores and also significantly influences the growth of SHG signal and the improved relaxation behavior after the poling field is removed, reducing the visible damage to the polymer film dramatically. This new pulsed corona poling experiment gave direct in situ evidence that the NLO chromophore and the polymer backbone undergo anisotropic rearrangement during the poling process.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.6
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• pp.497-503
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• 2004

One of the most difficult problems to damage in dentistry is an odontogenic infection. These infections may range from low-grade, well-localized infections that require only minimal treatment to a severe, life-threatenig fascial space infection. Although the overwhelming majority of odontogenic infections are easily managed by minor surgical procedures and supportive medical therapy that includes antibiotic administration, the practitioner must constantly bear in mind that these infections may become severe in a very short time. We made an investigation was targeting on 78 male and 47 female patients (125 patients in total) who had been hospitalized because of the fascial space abscess on the oral and maxillofacial area and gained a complete recovery in Daegu Catholic University Hospital, Oral & Maxillofacial Surgery from January 1999 to December 2003. By tracing their charts, we could grasp the characteristics such as age, gender, the time of breakout and specific areas of the attacks, making a conclusive study of the statistical analysis and finally, we could reach conclusions. Now, we report the conclusion from the investigation with the literature. The proportion of males and females was approximately 3 to 2, and in age group, patients under 10 years old marked the highest, 22.4%. The patients between the age of 10 and 40 were only 14.4%, yet those who were between 40 and 80 marked 53.6% in contrast. In the monthly distribution, the order was Dec.(13.6%)-Sep.(12%)-Jan.(10.4%) and in seasonal distribution, it was winter(30.4%)-fall(28%)- summer(24.4%)- spring(19.2%). Considering the medical history, D.M. was the highest which was 30.3%, hypertension marked 24.4%, and the patients with both D.M. and hypertension were 9.0%. The major cause of infection of oral and maxillofacial areas was odontogenic infection, which marked about 96%, and especially the cases related to dental caries occurred most frequently, which was 51.2%. In the number of relaxed fascial space, single fascial space was 81.6%, and in the degree of relaxation of fascial space, the buccal space abscess marked 40.8%, following submandibular space abscess, which was 30.4%.