• Tuberculosis and Respiratory Diseases
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• v.63 no.5
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• pp.417-422
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• 2007

Background: It is not known with certainty whether patients with persistently positive sputum smear results who have also had negative sputum culture results require prolongation of treatment for tuberculosis in order to avoid an increased risk of eventual relapse. The purpose of the present study was to retrospectively describe the treatment characteristics and evaluate the appropriate duration of treatment in these patients. Methods: Sixty of 69 patients with sputum smear positive and culture negative tests at 5 months after first line anti-tuberculous chemotherapy from 2002 to 2003 were retrospectively analyzed. Exclusion criteria included incomplete treatment or resistance to rifampicin or two additional antibiotics, as determined by a drug susceptibility test (DST). Results: Smear conversion of the study subjects was observed after $8.3{\pm}2.3$ months treatment, and the patients were culture negative after $2.0{\pm}0.8$ months. The relapse rates of the study subjects were 3.8, 10.0, and 25.8% after 1, 2, and 5 years of anti-tuberculosis chemotherapy, respectively. The relapse rates were not significantly affected by a series of risk factors such as age, sex, presence of diabetes, a sputum culture examination after 2 months treatment, previous treatment history, chest radiograph, and duration of the treatment (P>0.05). Conclusion: Regimen change is not required for patients with persistent smear positive but culture negative tests in the fifth month for first line antituberculous treatment. However, a further study will be needed to clarify the high relapse rate in this specific group of patients.

• Journal of Haehwa Medicine
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• v.9 no.1
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• pp.201-214
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• 2000

Precise and detailed clinical research and evaluation based on objective standards are imperative factors in securing reliability of a clinical test. Built on this principle, this clinical test has been conducted during the period between March 1999 and March 2000 dealing with 31 outpatients treated with ShiHo-GuizhiTang or ShiHo-GuizhiTang modify and ShiHo-GuizhiTang mixed prescriptions at the Sung-bo ORIENTAL MEDICAL CLINIC. A variety of information relating to those patients has been collected and analyzed under such criteria as precise diagnoses and their clinical effectiveness. The analysis was duly based on "The theory of cold syndrome". Then, the 31 patients' individual clinical information was compared one another by breaking down the results into sub-categories including gender, age, disease, main symptom, blood pressure, pulse beats, syndrome of abdomen, treatment period, modify and mixed prescription, and evaluation. The result of this clinical test can be summarized as follows: First, ShiHo-GuizhiTang appears to be more frequently prescribed in the case of female patients than in the case of male patients despite the fact that it does not necessarily need to be applied only to female. In addition, the numbers of prescriptions of ShiHo-GuizhiTang in the two age groups consisting of elementary school children and economically active adults respectively were the highest among other age groups. Second, ShiHo-GuizhiTang proved to be most effective in treatment for respiratory ailments and arthritis. Third, ShiHo-GuizhiTang brought down blood pressure of hypertension patients and at the same time benefited patients with normal or lower-than-normal blood pressure who were vulnerable to diseases due to low disease-resistance. Fourth, ShiHo-GuizhiTang was effective in the case of frequent pulse(rapid pulse) and thereby indicating the fact it carries Taiyang superficies syndrome. 지맥 arises from suppressed immune responses owing to adrenocortical hormones. ShiHo-GuizhiTang controls and revitalizes those suppressed immune systems which stem from slow pulse and, as a consequence of that process, helps them return to normal condition of pulse. Fifth, from the standpoint of syndrome of abdomen, feeling of obstruction in the epigastrium serves as an important standard in the process of diagnosing diseases and evaluating effectiveness of treatments. Sixth, according to the results of the clinical test with the 31 patients, a total of 81 percent of test subjects benefited from the treatment. The figure is the sum of 52 percent of I-class (both main symptom and accompanying symptoms had been eliminated) and 29 percent of II-class (part of main symptom and accompanying symptoms had been eliminated) respectively. All told it is safe to say that ShiHo-GuizhiTang can elect to be a viable clinical treatment. In conclusion, it is estimated that this clinical study has drawn up guidelines for objective diagnostic standards and evaluation on specific treatments' effectiveness. This will lead to more general application of ShiHo-GuizhiTang. On top of that, this study could also provide an opportunity to stress the significance of ShiHo-GuizhiTang and ShiHo-GuizhiTang modify and ShiHo-GuizhiTang mixed prescriptions as an alternative treatment for collagen disease which comes from environmental degradation and pollution.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.2
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• pp.249-263
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• 2017

The expansion behavior of inflatable steel pipe rockbolt shows geometric nonlinearity due to its ${\Omega}-shaped$ section. Previous studies on the anchoring behavior of inflatable steel pipe rockbolt were mainly performed using theoretical method. However, those studies oversimplified the actual behavior by assuming isotropic expansion of inflatable steel pipe rockbolt. In this study, the anchoring behavior of the inflatable steel pipe rockbolt were investigated by the numerical method considering the irregularity of pipe expansion and other influencing factors. The expansion of inflatable steel pipe rockbolt, the contact stress distribution and the change of the average contact stress and the contact area during installation were analyzed. The contact stresses were developed differently depending on the constitutive behavior of rocks. Small contact stresses occurred in steel pipes installed in elasto-plastic rock compared to steel pipes installed in elastic rock. Also, the anchoring behaviors of the inflatable steel pipe rockbolt were different according to the stiffness of the rock. The steel pipe was completely unfolded in the case of the stiffness smaller than 0.5 GPa, but it was not fully unfolded in the case of the stiffness larger than 0.5 GPa for the given analysis condition. When the steel pipe is completely unfolded, the contact stress increases as the rock stiffness increases. However, the contact stress decreases as the rock stiffness increases when the steel pipe is not fully expanded.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.9
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• pp.768-773
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• 2016

Engine valve seat and face, which are the important factors affecting engine performance, are required to have wear, heat and corrosion resistance. In order to produce surface layer with these characteristics, PTA(plasma transferred arc) surfacing procedure is generally employed, but problems, such as large HAZ and high dilution etc., frequently occurr. Laser cladding, which overcomes the drawbacks of conventional technologies, can be employed to create a superior clad layer with low dilution, small heat affected zone, and minimal distortion. However, in case cladding is to be applied to a large area, it is necessary to overlap 1 pass clad layer because of limited clad layer width. Two criteria for the overlapping ratio-beam size and clad layer width-have been considered thus far. Upon inspection of multi pass clads, produced by different overlapping criteria, it was observed that the greater the increase in overlapping ratio, the greater was the decrease in clad layer width and increase in clad layer height regardless of the criterion used. However, a multi pass clad overlapped by the beam size criterion demonstrated a higher hardness value than a clad overlapped by the clad layer width owing to decreasing dilution of the substrate. In conclusion, the beam size was defined as the criterion for the overlapping, because the clad layer width increased or decreased depending upon process parameters.

• Solar Energy
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• v.17 no.4
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• pp.3-11
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• 1997

Because grain boundaries in polycrystalline silicon act as potential barriers and recombination centers for the photo-generated charge carriers, these defects degrade conversion effiency of solar cell. To reduce these effects of grain boundaries, we investigated various influencing factors such as thermal treatment, various grid pattern, selective wet etching for grain boundaries, buried contact metallization along grain boundaries, grid on metallic thin film. Pretreatment above $900^{\circ}C$ in $N_2$ atmosphere, gettering by $POCl_3$ and Al treatment for back surface field contributed to obtain a high quality poly-Si. To prevent carrier losses at the grain boundaries, we carried out surface treatment using Schimmel etchant. This etchant delineated grain boundaries of $10{\mu}m$ depth as well as surface texturing effect. A metal AI diffusion into grain boundaries on rear side reduced back surface recombination effects at grain boundaries. A combination of fine grid with finger spacing of 0.4mm and buried electrode along grain boundaries improved short circuit current density of solar cell. A ultra-thin Chromium layer of 20nm with transmittance of 80% reduced series resistance. This paper focused on the grain boundary effect for terrestrial applications of solar cells with low cost, large area, and high efficiency.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.2
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• pp.143-166
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• 1999

The success of porcelain laminate veneer depends on the bond strength between tooth structure and ceramic restoration and the design of tooth preparation. In particular, incisal coverage and incisal finish line are the two most important factors in long-term fracture resistance. Although the majority of clinicians are practicing incisal coverage and there are various opinions on the geo-metrical ratio between the clinical crown length of the remaining tooth structure and the length of incisal extension in porcelain laminate veneer and the optimal incisal finish lines. scientific evidence still loaves much to be desired. The purpose of this study was to determine the effects of the amounts of incisal coverage and the types of incisal finish line on the stress distribution in maxillary anterior porcelain laminate veneers under two different loading conditions. Three-dimensional finite element models of a maxillary anterior porcelain veneer with differ-ent amounts of incisal coverage ; 0, 1, 2, and 3mm and different incisal finish lines feathered edge, incisal bevel, reverse bevel and lingual chamfer with various amounts of lingual extension were developed. 300N force was applied at the point 0.5mm cervical of the linguoincisal edge in two loading conditions ; A) 125 degrees, B) 132 degrees. Tensile and compressive stress in ceramic and shear stress in the resin cement layer were analyzed using three-dimensional finite element method. The results were as follows : 1. The types of incisal finish line had more influence on the stress distribution in porcelain laminate veneer than the amounts of incisal coverage. 2. In case of no incisal coverage, incisal beveled laminate exhibited more evenly distributed tensile stress than feathered edged laminate. And in case of incisal coverage, reverse beveled laminate and lingual chamfered laminate with 1mm lingual extension exhibited more evenly distributed tensile stress than lingual chamfered laminates with 2mm and 3mm lingual extension. 3. As long as the lingual chamfer goes, less tensile stress was found at the incisal edge, while much more tensile stress was found at the lingual margin area in proportion to the length of lingual extension. 4. Under 125 degree load, tensile stress in porcelain laminate veneer had increased compared with that under 132 degree load and the difference exhibited by the change of the amount of tooth support was larger. 5. The types of incisal finish line and the distance from the incisal finish line to the loading point had more influence on the shear stress distribution in the resin cement layer than the amounts of incisal coverage. In contrast loading condition had little influence.

• Membrane Journal
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• v.15 no.3
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• pp.206-212
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• 2005

Acid-resistant poly(vinyl alcohol) (PVA) membranes connected with ethylene and ether groups were prepared via a thermal crosslinking reaction by varying the ratio of PVA to ethylene glycol diglycidyl ether (EGDE). The crosslinked membranes were characterized using FT-IR and swelling tests, respectively. Pervaporation behaviors with the PVA membranes were investigated for aqueous TFEA (2,2,2-trifluoroethanol) as a function of EGDE content and operating temperature. The pervaporation properties far MA (methacrylic acid)/water mixture were also carried out with the optimized PVA membrane. The PVA membranes prepared with EGDE showed more excellent acid-resistance than those crosslinked with gluaraldehyde. The membranes showed high permeation fluxes of 0.1 and $0.3\;km^2h$ and high separation factors of 100 and 900 in the $96\;wt\%$ TFEA and MA aqueous fred mixtures at high temperature above $80^{\circ}C$, respectively. These confirmed theses membranes could be used in esterification membrane reactor process for the production of 2,2,2-trifluoroethylmetacrylate (TFEMA).

• Journal of the Korea Concrete Institute
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• v.17 no.4 s.88
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• pp.489-498
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• 2005

Recently, the deterioration of concrete structures have been increased by the damage from salt, carbonization, freezing & thawing and the others. Therefore, the measures for the deterioration of concretes have been taken. Among them, it has been often used that surface treatment which cut off the deterioration factors of durability by protecting the surface of concrete. The water proof and repair materials for concrete mainly use organic materials such as epoxy, these materials excel in intial bonding force and resistance to chemical agents. But they cause difference in the modulus of elasticity and the rate of shrinkage and expansion of concrete, and thus result in such problems as scaling and spatting in the progress of time. Therefore in this study it develop the performance Improving agent of concrete surface that can block a deterioration cause such as $CO_2$ gas, chloride ion and water from the outside and enhance waterproofing ability by reinforcing the concrete surface when applying it to concrete structures.

• Journal of the Korea Institute of Building Construction
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• v.18 no.3
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• pp.203-210
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• 2018

Corrosion of the rebar is one of the main factors affecting the durability of reinforced concrete in the world which lead to the failure of the reinforced concrete structures. In this research, a new method of fixing $CO_2$ is practiced to improve the carbonation resistance of the concrete. Brucite($Mg(OH)_2$), a kind of common $CO_2$ fixation materials, was added into ordinary Portland cement paste. Samples containing 0%, 5%, 10%, and 15% $Mg(OH)_2$ were exposed to an accelerated carbonation curing regime with 20% concentration of $CO_2$, 60% relative humidity, and a temperature of $20^{\circ}C$ until tested at 3d, 7d, 14d and 28d. After 28d of $CO_2$ accelerated curing, in the paste containing $Mg(OH)_2$, magnesian calcite was detected by SEM-EDX. Meanwhile, the paste containing $Mg(OH)_2$ exhibit the better pore distribution than ordinary Portland cement paste and the compressive strength of the cement paste containing $Mg(OH)_2$ were more than 50Mpa.

• Journal of the Korean Electrochemical Society
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• v.16 no.3
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• pp.111-122
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• 2013

Sodium sulfur (NAS) battery is a high energy storage system (ESS). These days, as the use of renewable green energy like wind energy, solar energy and ocean energy is rapidly increasing, the demand of ESS is increasing and NAS battery is considered to be one of the most promising ESS. Since NAS battery has a high energy density(3 times of lead acid battery), long cycle life and no self-charge and discharge, it is a good candidate for ESS. A NAS battery consists of sulfur as the positive electrode, sodium as the negative electrode and ${\beta}$"-alumina as the electrolyte and a separator simultaneously. Since sulfur is an insulator, carbon felt should be used as conductor with sulfur and so the composition and property of the cathode could largely influence the cell performance and life cycle. Therefore, in this paper, the composition of NAS battery, the property of carbon felt and sodium polysulfides ($Na_2S_x$, intermediates of discharge), and the effects of these factors on cycle performance of cells are described in detail.