• Journal of the Korean Society of Combustion
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• v.10 no.1
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• pp.20-26
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• 2005

In the present study, catalytic combustion of hydrogen-air premixture in a millimeter scale monolith coated with Pt catalyst was investigated. As the combustor size decreases, the heat loss increases in proportion with the inverse of the scale of combustion chamber and combustion efficiency decreases in a conventional type of combustor. Combustion reaction assisted by catalyst can reduce the heat loss by decreasing the reaction temperature at which catalytic conversion takes place. Another advantage of catalytic combustion is that ignition is not required. Platinum was coated by incipient wetness method on a millimeter scale monolith with cell size of $1{\times}1mm$. Using this monolith as the core of the reaction chamber, temperatures were recorded at various locations along the flow direction. Burnt gas was passed to a gas chromatography system to measure the hydrogen content after the reaction. The measurements were made at various volume flow rate of the fuel-air premixture. The gas chromatography results showed the reaction was complete at all the test conditions and the reacting species penetrated the laminar boundary layer at the honeycomb and made contact with the catalyst coated surface. At all the measuring locations, the record showed monotonous increase of temperature during the measurement duration. And the temperature profile showed that the peak temperature is reached at the point nearest to the gas inlet and decreasing temperature along the flow direction.

• Journal of Environmental Science International
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• v.18 no.4
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• pp.445-450
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• 2009

In this study, the fundamental experiments were performed for catalytic oxidation of NO (50 ppm) on $MnO_2$ in the presence of ozone. The experiments were carried out at various catalytic temperatures ($30-120^{\circ}C$) and ozone concentrations (50-150 ppm) to investigate the behavior of NO oxidation. The honeycomb type $MnO_2$ catalyst was rectangular with a cell density of 300 cells per square inch. Due to $O_3$ injection, NO reacted with $O_3$ to form $NO_2$, which was adsorbed at the $MnO_2$ surface. The excessive ozone was decomposed to $O^*$ onto the $MnO_2$ catalyst bed, and then that $O^*$ was reacted with $NO_2$ to form $NO_3^-$. It was found that the optimal $O_3$/NO ratio for catalytic oxidation of NO on $MnO_2$ was 2.0, and the NO removal efficiency on $MnO_2$ was 83% at $30^{\circ}C$. As a result, NO was converted mainly to $NO_3^-$.

• Journal of Apiculture
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• v.32 no.4
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• pp.391-394
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• 2017

Propolis is made by bees collecting protective material or essence of plants and mixing with saliva and enzymes produced by the salivary glands. It is used to repair the inside of the honeycomb, keep it sterile, and adjust the temperature and humidity. Propolis is a natural antibiotic substance that it is used to make a clean room by coating the cell before the queen bee lay eggs, and preventing the bacteria from invading by using with wax when sealing the nursery room. Propolis extract is a health functional food with antioxidant and oral antimicrobial effects. In order to use propolis in food, its active ingredients are extracted with ethanol. Water-soluble propolis was prepared by mixing and stirring honey and ethanol extracted propolis (EEP) solution. When 1kg of honey and 100ml of ethanol extracted propolis solution were mixed and stirred, the total flavonoid content of water-soluble propolis was $6.6{\pm}1.1mg/10g$, and the free radical scavenging effects of water-soluble propolis were 54 to 74%.

• Journal of Yeungnam Medical Science
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• v.39 no.2
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• pp.153-160
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• 2022

Multicentric Castleman disease (MCD) is an uncommon systemic lymphoproliferative disorder that may cause multiple organ damage. Castleman disease-associated diffuse parenchymal lung disease (DPLD) has not been well studied. A 32-year-old man was referred to our hospital for progressive generalized weakness, light-headedness, and dyspnea on exertion for more than one year. Laboratory evaluations showed profound anemia, an elevated erythrocyte sedimentation rate, and an increased C-reactive protein level with polyclonal hypergammaglobulinemia. Chest radiography, computed tomography (CT), and positron emission tomography-CT scan demonstrated diffuse lung infiltration with multiple cystic lesions and multiple lymphadenopathy. In addition to these clinical laboratory findings, bone marrow, lung, and lymph node biopsies confirmed the diagnosis of idiopathic MCD (iMCD). Siltuximab, an interleukin-6 inhibitor, and glucocorticoid therapy were initiated. The patient has been tolerating the treatment well and had no disease progression or any complications in 4 years. Herein, we report this case of human herpesvirus-8-negative iMCD-associated DPLD accompanied by multiple cystic lesions, multiple lymphadenopathy, and polyclonal hypergammaglobulinemia with elevated immunoglobulin G (IgG) and IgG4 levels. We recommend a close evaluation of MCD in cases of DPLD with hypergammaglobulinemia.

• Steel and Composite Structures
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• v.49 no.4
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• pp.393-405
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• 2023

In this paper, the energy absorption capability of a novel cruciform composite lattice structure was evaluated through the simulation of compression tests. For this purpose, several test samples of Polylactic acid cellular reinforced with continuous glass fibers were prepared for compression testing using the additive manufacturing method of material extrusion. Using a conventional path design for material extrusion, multiple debonding is probable to be occurred at the joint regions of adjacent cells. Therefore, an innovative printing path design was proposed for the cruciform lattice structure. Afterwards, quasistatic compression tests were performed to evaluate the energy absorption behaviour of this structure. A finite element model based on local material property degradation was then developed to verify the experimental test and extend the virtual test method. Accordingly, different combinations of unit cells' dimensions using the design of the experiment were numerically proposed to obtain the optimal configuration in terms of the total absorbed energy. Having brilliant energy absorption properties, the studied cruciform lattice with its optimized unit cell dimensions can be used as an energy absorber in crashworthiness applications. Finally, a cellular structure will be suitable with optimal behavior in crush load efficiency and high energy absorption.

• Applied Microscopy
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• v.32 no.1
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• pp.57-66
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• 2002

The structures of sucker of two Cobiidae; Common freshwater goby and Triden goby were observed by light and electron microscopy. Scanning electron microscopy revealed the characteristic narrow ridges and grooves on the apical portion of sucker of Common freshwater goby, and hexagonal structures similar to a honeycomb representing the intercellular junctional area on the middle and basal portions. Some ridges were present on the epithelial surface on the middle and basal portions. The openings of several mucus-secreting cells were present between main epithelial cells. Light and transmission electron microscopy revealed the core of the fin; soft rays with a surrounding dense collagen fiber layer. Some loosely arranged fibers (collagen fiber) radiated toward the surface epithelium. The surface epithelium was cuboidal or columnar in shape. Scanning electron microscopy revealed the coiled irregular ridges and grooves, which was less developed and had sparser distribution than in Common freshwater goby, on the apical portion of sucker of Triden goby. The middle and basal portions had honeycomb structures as in Common freshwater goby. Fewer mucoussecreting cells were present. Light and transmission electron microscopy showed the core of soft rays, dense collagen fiber layer, however, the radiating fibers observed in the Common freshwater goby was rarely present. The sucker was thinner because the epithelium is squamous or polygonal in shape and rare presence of the radiating fibers.

• Journal of the Korean Vacuum Society
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• v.15 no.1
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• pp.37-44
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• 2006

The homoepitaxy of Si(5 5 12) at $495^{\circ}C$ has been studied by Scanning Tunneling Microscopy under ultrahigh vacuum. A Si-dimer is the basic building-block and preferentially adsorbs on a unique site, that is, the Si-dimer/adatom site at the (337) and the (225) subsections within the Si(5 5 12) unit cell. The Si(5 5 12) unit cell is faceted to $3\times(337)$ subsections filled with Si-addimers and $1\times(113)$ subsection. In this step the tetramer at the other (337) section within the unit cell is transformed to a dimer/adatom site which can accept Si-dimers. Each (337) section is faceted to $1\times(112)\;and\;1\times(113)$, and then finally the unit cell of Si(5 5 12) is faceted to $3\tiems(112)\;and\;4\times(113)$ and forms the facet of effective height, $2.34{\AA}$. In this step, mutual transformation between the honeycomb chain and the dimer/adatom occurs. Finally, the valley between (112) and (113) facets is filled. If once the last step is completed, the uniform and planar Si(5 5 12) terrace is recovered. From the present study, therefore, it can be concluded that the homoepitaxy on Si(5 5 12) is periodically achieved and such growth mode is quite unique since faceting of the substrate-unit-cell plays a critical role for controlling uniformity of the overlayer.

• The Korean Journal of Cytopathology
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• v.4 no.2
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• pp.105-110
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• 1993

The major limitation of fine needle aspiration of the thyroid is in the evaluation of follicular tumors. it may be difficult or occasionally, impossible to distinguish on a cytologic basis, between hyperplastic nodular getter, follicular adenoma and well differentiated follicular carcinoma. We reviewed cytologic presentations of 15 histologically confirmed follicular neoplasms of the thyroid. Aspiration smears of 6 follicular adenomas were cell-rich with ball-like or syncytial aggregates of monotonous follicular cells, in contrast to honeycomb-like flat sheets of adenomatous goiter Mild nuclear pleomorphism and a small visible nucleolus were noted in 2 cases, respectively. Nine cases of follicular carcinoma showed very high cellularity, irregularly shaped cell clusters, and numerous isolated tumor cells. Nuclear pleomorphism and visible nucleoli were noted in 6 and 5 cases, respectively. Another characteristic finding, entrapped endothelial cells within the ceil clusters, was noted in 7 carcinomas and 1 adenoma. The background of the smears of all follicular neoplasms was hemorrhagic, with no or scanty colloid. We confirmed that the cytologic features of follicular adenoma and carcinoma were similar in general, with subtle differences in cell morphology, but the presence of isolated tumor cells and entrapped endothelial cells was suggestive of malignancy.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.4
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• pp.314-320
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• 2011

In this work, optimization of two-stage shock absorption system for lunar lander has been carried out. Because of complexity of impact phenomena of shock absorption system, a 1-D constitutive model is proposed to describe the behavior of shock absorption system. Quadratic polynomial regression meta-model is constructed by using a commercial software ABAQUS with the proposed 1-D constitutive model, and sequential approximate optimization of two-stage shock absorption system has been carried out along with the constructed meta-model. Through the optimization, it is verified that landing impact force on lunar lander can be considerably reduced by changing the cell size and foil thickness of honeycomb structure in two-stage shock absorption system.

• Korean journal of applied entomology
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• v.34 no.3
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• pp.266-277
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• 1995

The adult brown planthopper possesses tow oval shaped compound eyes which, on their ventral borders, curve around the base of the antennae. Compound eye of the adult brown planthopper is recognised apposition eye which each ommatidium is optically isolated from it surroundings, the rhabdoms receiving light only from their own corneal lens. Each ommatidium possesses its own dioptric apparatus formed from the cuticular cornea and an underlying crystalline cone. The retinula cells lying immediately beneath the crystalline cone have their individual rhabdomeres tightly opposed to form one central, closed rhbdom. The rhabdom stretches from the spex of the crystalline cone nearly to the basement membrane and is approximately 110~120 $\mu\textrm{m}$ in length. The crystalline cone is surrounded by a pair of primary pigment cells an these in turn are surrounded by accessory pigment cells. Accessory pigment cells extend beyond the crystalline cone surrounding the retinular cells in the distal region of the eye. The crystalline cone is surrounded by the distal-most regions of the retinula cells show the presence of seven cells and sections taken proximally in the last quarter of the omatidium before the basement membrane is reached, reveal the presence of a small, eighth retinula cell which also contributes to the central rhabdom. Each ommatidium has a central rhabdom formed from the modified inner border of all of the retinula cells. Th rhabdom consists of micrvilli arising from the inner wall of each retinula cell. In cross section th microvilli exhibit a characteristic honeycomb appearance. Pigment cells comprise the primary pigment cells enveloping the crystalline cone, the accessory pigment cells extending from the inner surface of the comea to the basement membrane and the small pigment cells of the basement membrane.