• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.6
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• pp.30-37
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• 1989

The PIN type a-SiC:H/a-Si:H heterojunction solar cells were fabricated by using the rf glow discharge decomposition of $SiH_4$ mixed with $CH_4,B_2,H_6\;and\;PH_3.$ The efficiency of the solar cell of the $SnO_2/ITO$ was higher than that of ITO transparent oxide layer by 1.5%. The P layer was prepared with the thickness of $100{\AA}$ and $CH_4/SiH_4$ ration of 5. The I layer has been deposited on the P layer and it is not pure intrinsic but near N type. So $SiH_4$ mixed with $B_2H_6$ of 0.3ppm was used to change this N type nature to intrinsic having the thickness of 5000${\AA}$. And consecutively, the N layer was deposited with t ethickness of $400{\AA}$ using $SiH_4/PH_3$ mixtures. The solar cell demonstrated 0.94V of $V_{oc'}$ 14.6mA/cm of $J_{sc}$ and 58.2% of FF, resulting the efficiency of 8.0%. To minimize loss by the reflection of light, $MgF_2$ layer was coated on the lgass and the efficiency was improved by 0.5%. Therefore, the solar cell indicated overall efficiency of 8.5%.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.3
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• pp.352-358
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• 2020

Glanzmann's thrombasthenia (GT) is a rare, autosomal recessive inherited congenital disorder, characterized by impaired blood coagulation due to platelet dysfunction. It was first reported by the pediatrician Glanzmann in 1918. GT affects both males and females, and it is more common in regions of the Middle East, India, and France, where intermarriage is common. It has an incidence of about 1 in 1,000,000 people. In South Korea, according to the Division of Rare Diseases, Korea Centers for Disease Control and Prevention, around 200 cases have been reported in 2018. Clinical symptoms include petechia, ecchymosis, epistaxis, and gingival bleeding. The spontaneous loss of deciduous teeth can result in excessive bleeding with that blood transfusion should be considered. Preventing hemorrhages and hemostasis are most important factors in dental treatment. Local bleeding can be controlled by compression, but platelet transfusion can be required by prolonged bleeding. Pediatric dentists can minimize the gingival bleeding by control of the oral hygiene to prevent gingivitis and dental caries. The importance of oral hygiene and periodic recall check-up should be emphasized. During dental treatment, the examination and the treatment plan of patient should be modified to prevention of hemorrhages carefully. A 6-year-old girl with GT was referred for the treatment of dental caries, and resin restoration was performed under nitrous oxide inhalation sedation. After treatment, compression was required for the bleeding control.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.3
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• pp.20-40
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• 2003

Since unloaded Q-value of a high-temperature superconductor(HTS) filter is very high, a bandpass filter(BPF) and a lowpass filter(LPF) with an increase of pole numbers can be fabricated without an increase of an insertion loss(IL) ; recently a 70-pole BPF is developed in USA. They have an abrupt skirt property and an excellent attenuation level for out-of band. Moreover, they can be miniaturized when lumped element resonators or the slow-wave characteristic are used. Technology of fabricating a HTS epitaxial film as well as a film of a 4 inch area also makes the planar type filter with a various structure and an enhanced power handling capability possible. Recently, the HTS filter subsystems composed of a planar-type HTS filters, a GaAs-based LNA and a mini-cryocooler are developed. The extended receiver front- end subsystems for mobile radio communications decrease the noise-figure level of the communication system and the frequency interference interacted adjacent bands, and increase the efficiency of frequency and the capacity of communication system. In this paper, theory for developing the HTS filter, its kinds, its design rules, its characteristics are reviewed. The feature of the research and market trends related to the HTS filter systems for the receiver front-end subsystem of mobile base station are surveyed.

• The Korean Journal of Nuclear Medicine
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• v.1 no.2
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• pp.41-59
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• 1967

This study was aimed; firstly to observe various clinical symptomatology with reiation to the number of Ancylostoma duodenale larvae orally given to the human beings, secondly to evaluate the effects of some drugs like steroid hormones, antihistaminic3 and antitussives, and, thirdly to study the influences of some iron compounds in prevention and treatment of anemia of such origin. Ten healthy volunteers free from the previous history of hookworm infection were divided into 4 groups, to whom various numbers of actively moving filariform Ancylostoma duodenale larvae were orally given; 500 to 4 cases, 250 to 3 cases and 100 to 3 cases. Following were the results: 1. Clinical symptomatology 1. The most frequently encountered symptoms and signs were general malaise, cough and hoar seness. The tracheal itching and pain low back pain, arthralgia, sputum and salivation, acid belching, loss of appetite, abdominal pain and vomiting were also noted. 2. If the larger number of the larvae was given, the clinical symtomatology was more severe. 3. Prednisolone medication caused some improvement of such symptomatology, while the antihistaminics and antitussives like codeine or ephedrine were ineffective. 4. In volunteers whose nutritional conditions were rather poor appeared to show more severe symptomatology. 2. Effects of iron compounds 1. The oral administration of ferrous fumarate induced a slight increase of serum iron levels in the initial stage of the infection, then a decrease from $15{\sim}20$ days later and a recovery after 2 months. 2. The intravenous administration of saccharated ferric oxide induced a steady upkeep of the serum iron levels. 3. The hemoglobin contents also showed the upkeeps after either the oral or intravenous administration of the iron compounds. 4. The iron compounds, therefore, are considered to have the preventive as well as the therapeutic effects on hookworm anemia, which may strongly suggest that hookworm anemia is essentially the iron deficiency type. 3. Hematological changes 1. The severity of hookworm anemia generally correlated with the number of larvae given. 2. The moderate leucocytosis was observed in all cases regardless of the number of larvae given, which reached to a peak in $25{\sim}35$ days. 3. Eosinophilia was observed in all cases, but was more severe in cases given larger number of larvae, which was slightly less evident after the medication of prednisolone. 4. Red cell survival time The red cell survival time determined by $^{51}Cr$ was generally in the normal ranges except for the severe anemia patients.

• 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.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.4
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• pp.353-357
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• 1983

A field study was conducted for 20 soil columns to investigate the denitrification in the grassland with a method introducing $C_2H_2$ in the denitrifying system. Since acetylene blocked the pathway from $N_2O$ to $N_2$, all the free products of denitrification consisted of nitrous oxide. In this study, denitrification was measured as $N_2O$. Results are as follows. 1. In most of boils examined, denitrification was observed as $N_2O$ when acetylene was introduced into the denitrification system while $N_2O$ was scarcely evolved without acetylene in the system. 2. Denitrification occurred even in the grassland soils when they were saturated with water. Denitrification was nil or negligible without water saturation. 3. Denitrification loss far 3 days incubation(from 13th to 16th day after urea application) was 4.2% in average and 14.2% in maximum. 4. Soil chemical properties such as nitrate nitrogen, nitrite nitrogen, total nitrogen, total carbon and mineralizable carbon did not show clear relationships with denitrificatien, probably since soil chemical properties were analysed for the soils after incubation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.1
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• pp.14-17
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• 2014

In this study, lead-free Piezoelectric $(Na_{0.47}K_{0.47}Sr_{0.03}Ca_{0.03})(Nb_{0.94}Ti_{0.06})O_3$-0.1 $MnO_2$ ceramics were fabricated using mixed oxide method and the effects of various sintering temperature on the structural and electrical properties were investigated. For the $(Na_{0.47}K_{0.47}Sr_{0.03}Ca_{0.03})(Nb_{0.94}Ti_{0.06})O_3$-0.1 $MnO_2$ (NKN-SCT-$MnO_2$) ceramics sintered at temperatures of $1,025{\sim}1,100^{\circ}C$. The results indicated that all specimens were perovskite single phase formation without any second phase. It has been shown that relative density is increased to increasing sintering temperature. When the sintered temperature at $1,075^{\circ}C$, highest sintered density and maximum value of $4.45g/cm^3$. Average grain size is increased to increasing sintering temperature. The electromechanical coupling factor, dielectric constant, dielectric loss, d33 and curie temperature at the sintering temperature $1,075^{\circ}C$ of NKN-SCT-$MnO_2$ specimens were 0.22, 511, 0.033, 103 and $380^{\circ}C$, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.4
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• pp.550-555
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• 2013

Extrinsic skin aging is characterized by the loss of skin tone and resilience, irregular pigmentation, and deep wrinkles. The aim of this study was to investigate the effects of Ehwa Makgeolli containing oriental herbs (Glycyrrhiza uralensis Fisch., Lycium chinense MILL., Morus alba L., and Saururus chinensis Baill) on skin whitening and wrinkling in human skin cells. We prepared Makgeolli extracts (HEE) with 70% ethanol. HEE significantly inhibited in vitro mushroom tyrosinase activity and reduced the cellular and secreted melanin content of mouse melanoma melanocytes (B16F1 cells). HEE down-regulated the protein expression of tyrosinase related protein (TRP)-1/-2, a key player in melanogenesis. Treatment with HEE in human keratinoctyes (HaCaT cells) inhibited the proteolytic activities of matrix metalloproteinase (MMP)-2/-9 in a dose-dependent manner and dramatically reduced the expression of MMP-2/-9. In addition, HEE attenuated lipopolysaccharide (LPS)-induced nitric oxide production in murine macrophages (RAW264.7 cells). These results indicate that HEE may be a great cosmeceutical ingredient for its whitening, anti-wrinkle, and anti-inflammatory effects.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.12
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• pp.1415-1420
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• 2014

Super-critical $CO_2$ ($S-CO_2$) Brayton cycle has been considered to replace the current steam Rankine cycle in Sodium-cooled Fast Reactor (SFR) in order to improve the inherent safety and thermal efficiency. Several austenitic alloys are considered as the structural materials for high temperature $S-CO_2$ environment.. Microstructural change after long-term exposure to high temperature $S-CO_2$ environment could affect to the mechanical properties. In this study, candidate materials (austenitic stainless steels and Alloy 800HT) were exposed to $S-CO_2$ to assess oxidation resistance and the change in tensile properties. Loss of ductility was observed for some austenitic stainless steels even after 250 h exposure. The contribution of $S-CO_2$ environment on such changes was analyzed based on the characterization of the surface oxide and carburization of the materials in which 316H and 800H showed different oxidation behaviors.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.3
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• pp.250-256
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• 2000

The purpose of this study was to investigate the adsorption kinetics of heavy metals (Cu, Cd and Pb) using three tidal flat sediments and two yellow loesses. The relationship between adsorption rate calculated by non-linear regression model and chemical parameters was estimated. The contents of ignitiot loss (I.L.) am Fe, Mn and Al oxides of yellow loess were higher $1.5{\~}6 times$ than those of tidal flat sediments. But the contents of silt and clay of tidal flat sediment in Eueunri was higher than others. Heavy metals adsorption were occured rapidly in the intial 30 min and the concentration of adsorbed heavy metals were $4.1{\~}14.7\;{\mu}g/g\;for\;Cu,\;2.8{\~}16.7\;{\mu}g/g\;for\;Cd\;and\;43.4{\~}101.7\;{\mu}g/g$ for Pb, showing a high cumulative adsorption of $8{\~}70{\%}\;for\;Cu,\;18{\~}31{\%}\;for\;Cd and\;19{\~}52{\%}$ for Pb after 3hr. In initial concentration of $0.5{\times}10^(-5)M$, adsorption rate of heavy metals by the tidal flat sediments and yellow loesses was the sequence Pb>Cu^gt;Cd. The adsorption kinetics of Cu, Cd and Pb was found to be one-site kinetic model. Especially, in the case of Cu, there was a high negative ($R^2= -0.88{\~}-0.99$) linear correlation between chemical parameter such as I.L., Al oxide, silt and clay, and adsorption rate coefficients ($K_a$) calculated by non-linear model.