• Elastomers and Composites
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• v.30 no.3
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• pp.185-194
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• 1995

Membrane process has been employed to separate a specific substance from gas or liquid mixture, and treat wastewater. This is due to the fact that the substance of mixture can be permeated and separated selectively by membrane. Since Initial equipment and operation costs are not expensive, membrane process has been adopted in various fields such as petroleum Industry, chemistry, polymer, electronics, foods, biochemical industry and wastewater treatment. In this study, $CaCO_3$ particles impregnated in silicone rubber network were extracted by using supercritical carbon dioxide and pore distribution of silicone $rubber-CaCO_3$ was investigated with varying amount of extract. Silicone rubber has excellent mechanical properties such as heat-resistance, cold-resistance etc. and $CaCO_3$ has microporous structure. It is possible to make silicone $rubber-CaCO_3$ composite sheets via work-intensive kneading processes. In so doing $CaCO_3$ particles become distributed and impregnated in silicone rubber network. Supercritical carbon dioxide diffuse through composite sample, then sample is swollen. $CaCO_3$ in silicone rubber network Is dissolved in supercritical carbon dioxide, and its sites become pores. Pore distribution, pore shape and surface area are observed by SEM(scanning electron microscope) micrograph and BET surface area analyzer examination respectively. Pore characteristics of membrane suggest the possibilities that the membrane can be used for process of mixture separation and wastewater treatment.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.59.4-60
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• 2018

Ultra-diffuse galaxies (UDGs) are an unusual galaxy population. They are ghostlike galaxies with fainter surface brightness than normal dwarf galaxies, but they are as large as MW-like galaxies. The key question on UDGs is whether they are 'failed' giant galaxies or 'extended' dwarf galaxies. To answer this question, we study UDGs in massive galaxy clusters. We find an amount of UDGs in deep HST images of three Hubble Frontier Fields clusters, Abell 2744 (z=0.308), Abell S1063 (z=0.347), and Abell 370 (z=0.374). These clusters are the farthest and most massive galaxy clusters in which UDGs have been discovered until now. The color-magnitude relations show that most UDGs have old stellar population with red colors, while a few of them show bluer colors implying the existence of young stars. The stellar masses of UDGs show that they have less massive stellar components than the bright red sequence galaxies. The radial number density profiles of UDGs exhibit a drop in the central region of clusters, suggesting some of them were disrupted by strong gravitational potential. Their spatial distributions are not homogeneous, which implies UDGs are not virialized enough in the clusters. With virial masses of UDGs estimated from the fundamental manifold, most UDGs have M_200 = 10^10 - 10^11 M_Sun indicating that they are dwarf galaxies. However, a few of UDGs more massive than 10^11 M_Sun indicate that they are close to failed giant galaxies.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.42.1-42.1
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• 2018

Collisionless shocks with low sonic Mach numbers, M<4, are expected to accelerate cosmic ray (CR) protons via diffusive shock acceleration (DSA) in the intracluster medium (ICM). However, observational evidence for CR protons in the ICM has yet to be established. Performing particle-in-cell simulations, we study the injection of protons into DSA and the early development of a nonthermal particle population in weak shocks in high ${\beta}$ plasmas. Reflection of incident protons, self-excitation of plasma waves via CR-driven instabilities, and multiple cycles of shock drift acceleration are essential to the early acceleration of CR protons in supercritical quasi-parallel shocks. We find that only in ICM shocks with $M{\geq}2.3$, a sufficient fraction of incoming protons are reflected by the overshoot in the shock electric potential and magnetic mirror at locally perpendicular magnetic fields, leading to efficient excitation of magnetic waves via CR streaming instabilities and the injection into the DSA process. Since a significant fraction of ICM shocks have M < 2.3 CR proton acceleration in the ICM might be less efficient than previously expected. This may explain why the diffuse gamma-ray emission from galaxy clusters due to proton-proton collisions has not been detected so far.

• Tuberculosis and Respiratory Diseases
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• v.85 no.2
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• pp.122-136
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• 2022

Although chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD) have distinct clinical features, both diseases may coexist in a patient because they share similar risk factors such as smoking, male sex, and old age. Patients with both emphysema in upper lung fields and diffuse ILD are diagnosed with combined pulmonary fibrosis and emphysema (CPFE), which causes substantial clinical deterioration. Patients with CPFE have higher mortality compared with patients who have COPD alone, but results have been inconclusive compared with patients who have idiopathic pulmonary fibrosis (IPF). Poor prognostic factors for CPFE include exacerbation, lung cancer, and pulmonary hypertension. The presence of interstitial lung abnormalities, which may be an early or mild form of ILD, is notable among patients with COPD, and is associated with poor prognosis. Various theories have been proposed regarding the pathophysiology of CPFE. Biomarker analyses have implied that this pathophysiology may be more closely associated with IPF development, rather than COPD or emphysema. Patients with CPFE should be advised to quit smoking and undergo routine lung function tests, and pulmonary rehabilitation may be helpful. Various pharmacologic agents and surgical approaches may be beneficial in patients with CPFE, but further studies are needed.

• Tuberculosis and Respiratory Diseases
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• v.52 no.4
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• pp.411-418
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• 2002

Pulmonary alveolar proteinosis(PAP) is a disorder in which an insoluble, proteinaceous material, rich in phospholipids, is deposited in the alveoli and bronchioles. The deficiency in the clearance and degradation of the intra-alveolar phospholipoproteinaceous material in PAP most likely represents a dysfunction of the type II pneumocytes. Although the pathogenesis and causative treatment of PAP is unclear a whole lung bronchopulmonary lavage is a relatively safe and effective treatment. Here we experienced a case of pulmonary alveolar proteinosis in a 62 year old female patient who had pulmonary tuberculosis approximately 20 years ago. She complained of aggravated dyspnea and chronic cough, and presented fine inspiratory crackles at both lung fields, diffuse ground glass opacity with some area of consolidation and smooth interlobular septal thickenings in both upper, right middled lobes, and a portion of right lower lobe. Optical microscopy of the lung tissue obtained by and open lung biopsy revealed many granulomas containing acid-fast smear positive bacilli and diffuse homogeneous PAS-positive fluid in the alveolar space. Immunohistochemical stain showed surfactant. A in the alveolar space. Antituberculosis drugs with bronchoalveolar lavage were used to treat the disease. Thereafter she showed improvement in her symptoms and a partial improvement in the chest X-ray and HRCT findings. We present a case of PAP associated with pulmonary tuberculosis.

• Fire Science and Engineering
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• v.23 no.2
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• pp.67-77
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• 2009

The purpose of this study is to deal with fire fighting safety education primarily among the fields of child safety education. So, first of all, this study considered the theoretical background of fire fighting safety education. And this study analyzed the present state and cases of safety accidents in elementary schools. And by focusing on the fire fighting science class for elementary schools which Gyeonggi-do Goyang fire station is executing now, this study analyzed the educational outline, present state, educational goal, and content of fire fighting science class, and conducted the satisfaction survey through questionnaire over the elementary school students participating in fire fighting science class and the fire fighting officers in charge of fire fighting science class. On basis of this research, by developing the new field of fire fighting education and publicity into the program which can diffuse the fire fighting-related chemical experiment based on the science of chemistry and physics in the future and so provide the pleasure and surprise of experiencing directly not only natural fire fighting education and publicity but also learning and the common sense of fire fighting, this study tried to present the alternatives about the measures for activating the fire fighting safety education in elementary schools.

• Journal of the Mineralogical Society of Korea
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• v.15 no.1
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• pp.44-58
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• 2002

A new polymorph of tridymite, an incommensurately modulated phase (IC phase), has been identified. While the symmetry of the IC lattice is same as that of the Ll phase, the geometry of the IC lattice structure is same as the basis of the L3 structure with a different modulation (modulation vector q=0.22 $c*_{H}$;$\lambda$ 37 ). On the other hand, the characteristic curved diffuse diffration observed from the Ll atoms could occur even at room phase suggests that the dynamic disordering of atoms, especially oxygen atoms could occur even at room temperature. The phase transition of Ll to L3 by grinding is gradual but very conspicuous: LllongrightarrowL1+IClongrightarrowIC+L3longrightarrowL3. However, it is revealed that real transition processes of individual grains are directly related to the local stress fields and preexisting microstructures.

• Bulletin of the Korean Space Science Society
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• 2011.04a
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• pp.20.1-20.1
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• 2011

We present the results of far-ultraviolet (FUV) observations of comet C/2001 Q4 (NEAT) obtained with Far-ultraviolet Imaging Spectrograph (FIMS) on board the Korean microsatellite STSAT-1, which operated at an altitude of 700 km in a sun-synchronous orbit. FIMS is a dual-channel imaging spectrograph (S channel 900-1150 ${\AA}$, L channel 1350-1750 ${\AA}$, ${\lambda}/{\Box}{\lambda}$ ~ 550) with large image fields of view (S: $4^{\circ}.0{\times}4'.6$, L: $7^{\circ}.5{\times}4'.3$, angular resolution 5'-10') optimized for the observation of diffuse emission of astrophysical radiation. Comet C/2001 Q4 (NEAT) was observed with a scanning survey mode when it was located around the perihelion between 8 and 15 May 2004. Several important emission lines were detected including S I (1425, 1474 ${\AA}$), C I (1561, 1657 ${\AA}$) and several emission lines of CO $A1{\cap}-X1{\sum}+$ system in the L channel. We estimated QCO = ($2.58\;{\pm}\;0.64)\;{\times}\;1028$ s-1 from the production rate of CO 1510 ${\AA}$. We obtained L-channel image which have map size of $5^{\circ}{\times}5^{\circ}$. The image was constructed for the wavelength band of L-channel (1350-1750 ${\AA}$).We also obtained radial profile of S I, C I, CO with line fitting from central coma.

• Journal of Biosystems Engineering
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• v.33 no.4
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• pp.260-268
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• 2008

Optical diffuse reflectance sensing has potential for rapid and reliable on-site estimation of soil properties. For good results, proper calibration to measured soil properties is required. One issue is whether it is necessary to develop calibrations using samples from the specific area or areas (e.g., field, soil series) in which the sensor will be applied, or whether a general "factory" calibration is sufficient. A further question is if specific calibration is required, how many sample points are needed. In this study, these issues were addressed using data from 42 paddy fields representing 14 distinct soil series accounting for 74% of the total Korean paddy field area. Partial least squares (PLS) regression was used to develop calibrations between soil properties and reflectance spectra. Model evaluation was based on coefficient of determination ($R^2$) root mean square error of prediction (RMSEP), and RPD, the ratio of standard deviation to RMSEP. When sample data from a soil series were included in the calibration stage (full information calibration), RPD values of prediction models were increased by 0.03 to 3.32, compared with results from calibration models not including data from the test soil series (calibration without site-specific information). Higher $R^2$ values were also obtained in most cases. Including some samples from the test soil series (hybrid calibration) generally increased RPD rapidly up to a certain number of sample points. A large portion of the potential improvement could be obtained by adding about 8 to 22 points, depending on the soil properties to be estimated, where the numbers were 10 to 18 for pH, 18-22 for EC, and 8 to 22 for total C. These results provide guidance on sampling and calibration requirements for NIR soil property estimation.

• Tuberculosis and Respiratory Diseases
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• v.54 no.3
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• pp.338-345
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• 2003

A 65-year-old man was admitted due to low grade fever, dry coughing, and dyspnea on exertion. The chest radiograph and CT scan showed diffuse ground glass opacities and small nodules in the both lung fields resulting in a diagnosis of severe interstitial pneumonia. Conservative treatment with antibiotics and bronchodilators decreased the symptoms, but the dyspnea and cough reappeared when he returned home. An inspection of his house revealed the presence of fungi under the wallpaper. His symptoms disappeared completely after these were removed. His clinical course raised the suspicion of hypersensitivity pneumonitis and these fungi believed to be the cause of hypersensitivity pneumonitis. The histological findings of a lung specimen by video-assisted thorachoscopy were compatible with hypersensitivity pneumonitis. The fungi were identified as Alternaria.