• The Bulletin of The Korean Astronomical Society
• /
• v.36 no.2
• /
• pp.102.2-102.2
• /
• 2011

Sunspots usually appear in a group which can be classified by certain morphological criteria. In this study we examine the moments which are statistical parameters computed by summing over every pixels of contours, in order to quantify the morphological characteristics of a sunspot group. The moments can be additional characteristics to the sunspot group classification such as McIntosh classification. We are developing a program for image processing, detection of contours and computation of the moments using continuum images from SOHO/MDI. We apply the program to count the sunspot numbers from 303 continuum images in 2003. The sunspot numbers obtained by the program are compared with those by SIDC. The comparison shows that they have a good correlation (r=89%). We are extending this application to automatic sunspot classification (e.g., McIntosh classification) and flare forecasting.

• The Bulletin of The Korean Astronomical Society
• /
• v.34 no.1
• /
• pp.153.1-153.1
• /
• 2009

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.4 no.2
• /
• pp.137-147
• /
• 1994

This study was designed to identify and quantitate airborne isocyanate simultaneously by HPLC. These samples were collected using 1-(2-pyridyl)piperazine(1-2PP) coated glass fiber filter from polyurethane painting works at 8 wood furniture factories in Kimpo and Inchun. The results obtained were as follows : 1. The most suitable mobile phase condition of simultaneously analyzing isocyanates was 0.01 M ammonium acetate buffer ACN(70/30) adjusted to pH 6.2 from the beginning of the analysis to 20 min and 0.01 M ammonium acetate buffer/ACN(50/50) adjusted to pH 6.2 from 21 min to 40 min using the gradient mode. The peaks of isocyanates were able to obtain within 30 min. 2. The recovery efficiencies for 2,6-TDI, 2,4-TDI, HDI and MDI urea derivates spiked at the target concentration on coated glass fiber tillers were 91.00, 93.42, 91.31 and 94.21 %, respectively. 3. The qualitative analysis of the isocyanates samples from polyurethane spray painting works in wood furnture factories identified Ihree isocyanates, 2,6-TDI, 2,4-TDI and MOI. And their concentration ranges were 0-312.6, 0-56.3 and $0-62.1{\mu}g/m^3$, respectively. A disadvantage of using the colorimetric method for isocyanate analysis is its inability of separating isocyanates. This study identified such three isocyanates as 2,6-TDI, 2,4-TDI and MDI from polyurethane spray painting works in wood furniture factories. These isocyanates were successfully quantitated by HPLC by modifying the mobile phase condition and switching to gradient mode.

• Elastomers and Composites
• /
• v.47 no.3
• /
• pp.238-245
• /
• 2012

Graphene oxide was synthesized from natural graphite, and its surface was modified using diisocyanatodicyclohexylmethane( $H_{12}MDI$). Isocyanate-graphene sheet(i-RGO) was obtained by reduction of surface modified GO. To select nanofiller having good dispersion with polyurethane, GO, i-RGO, natural graphite and thermal reduced graphite were analyzed, and then i-RGO was selected as a suitable nanofiller. PU/i-RGO nanocomposite was synthesized with various i-RGO contents to estimate effect of reinforcement on nanocomposite. Thermal stability, hardness, contact angle were increased with i-RGO contents due to i-RGO characteristic and crosslink bridge effect. But, tensile strength and elongation were decreased at i-RGO contents more than the 4 wt%. This phenomenon was interpreted by the excess formation of crosslink bridge.

• Journal of the Korean Applied Science and Technology
• /
• v.34 no.4
• /
• pp.851-856
• /
• 2017

The mechanical properties of coating resin on stainless steel were measured by SEM, FT-IR spectra, tensile properties, mole ％ of [NCO/OH], and particle size analyzer. Growing concerns in the environment-friendly coating resin, we have synthesized the solvent-free coating resin to be coating on metals such as stainless steel. The properties of the synthesized coating resin to be contained polyols, MDI, silicone surfactant, fillers and vegetable oil(castor oil), that they have highly stronger in intensity and longer durability than general coating resin of polyurethane resin on stainless steel. The rigid segments of polyurethane in mechanical properties of coatings were due to unsaturated vegetable oil and the increase mole % of [NCO/OH]. In conclusion, the coating microstructure with castor oil can be good material for coatings of anticorrosion of metal substrates such as stainless steel.

• Tuberculosis and Respiratory Diseases
• /
• v.85 no.1
• /
• pp.25-36
• /
• 2022

Background: Only a few studies directly compared the therapeutic efficacy and safety of two pressurized metered-dose inhalers (pMDIs) in asthma. We analyzed the asthma treatment outcomes, safety, and patient preferences using formoterol/beclomethasone (FORM/BDP), a pMDI with extra-fine particles, compared with formoterol/budesonide (FORM/BUD), another pMDI with non-extra-fine particles. Methods: In this randomized, double-blind, double-dummy parallel group study, 40 adult asthmatics were randomized to FORM/BDP group (n=18; active FORM/BDP and placebo FORM/BUD) or FORM/BUD group (n=22; active FORM/BUD and placebo FORM/BDP). During the two visits (baseline and end of 8-week treatment), subjects were asked to answer questionnaires including asthma control test (ACT), asthma control questionnaires (ACQ), and Quality of Life Questionnaire for Adult Korean Asthmatics (QLQAKA). Lung function, compliance with inhaler, and inhaler-handling skills were also assessed. Results: Ten subjects in the FORM/BDP group and 14 in the FORM/BUD group completed follow-up visits. ACT, ACQ, QLQAKA (a primary outcome), and adverse events did not differ between two groups. We found that the increase in forced expiratory volume in 1 second/forced vital capacity and forced expiratory flow at 25% to 75% of the pulmonary volume in the FORM/BDP group was higher than in the FORM/BUD group. Regarding preference, subjects responded that the flume velocity of FORM/BDP was higher, but more adequate than that of FORM/BUD. They also answered that FORM/BDP reached the trachea and bronchus and irritated them significantly more than FORM/BUD. Conclusion: The use of pMDI with extra-fine particles may relieve small airway obstruction more than the one with non-extra-fine particles despite no significant differences in overall treatment outcomes. Some asthmatics have a misconception about the adequacy of high flume velocity of pMDIs.

• Applied Chemistry for Engineering
• /
• v.9 no.4
• /
• pp.491-496
• /
• 1998

The composition of isocyanates and polyols influence prepolymeric properties of adhesive and calking sealant based on polyurethanes (PU). One component moisture curing prepolymers, which reacted with surface humidity of substrate, were synthesized in several kinds of composition. Reactivity, structural change and properties of the prepolymers were studied as a preliminary step to manufacture PU based adhesive and sealant. To study the effects of mole ratio ([NCO]/[OH]), we used toluene diisocyanate (TDI), 4, 4'-diphenylmethane diisocyanate (MDI), and ether-polyols such as PTMG and PPG which have good resistance to hydrolysis and excellent low-temperature properties. The each prepolymers could be prepared in different molecular weight without any significant structural change. The mole ratio 1.78 of [NCO] to [OH] showed the fastest reactivity. It was confirmed that effect of polyols was larger than that of isocyanates on the prepolymer in reactivity. Several kinds of compounds were manufactured with each prepolymer, and tensile and properties were tested. And the optimum quantity of curing accelerator for the PU was 0.05~0.1%. In the tensile test, TDI based PU was superior to MDI based PU, and also PTMG based PU was superior PPG based PU.

• Journal of Life Science
• /
• v.25 no.3
• /
• pp.299-306
• /
• 2015

Chrysanthemum zawadskii, a herbaceous perennial plant belonging to the Compositae, grows wild in Asian countries, including Japan, China, and Korea. The biological, antioxidative, anti-inflammatory, and antibacterial activities of C. zawadskii have been reported, its antiobesity activity has not been elucidated. In the present study, the effect of C. zawadskii methanol extract (CZME) on pancreatic lipase enzyme activity, adipocyte differentiation, and adipogenesis was investigated using an in vitro assay and a cell model system. CZME effectively suppressed lipase enzyme activity in a dose-dependent manner. CZME also inhibited insulin, dexamethasone, 3-isobutyl-1-methylxanthine (MDI)-induced adipocyte differentiation, lipid accumulation, and the level of triglyceride in 3T3-L1 preadipocytes in a dose-dependent manner, without cytotoxicity. The antiobesity effect of CZME might be modulated by gene and protein expression of cytidine-cytidine-adenosine-adenosine-thymidine (CCAAT)/enhancer binding proteins (C/EBP) α, C/EBPβ, and the peroxisome proliferator-activated receptor γ (PPAR γ). CZME also triggered lipolysis in a dose-dependent manner in MDI-induced 3T3-L1 preadipocytes. Taken together, these results provide important new insights into the antiobesity activities of C. zawadskii, showing that they involve pancreatic lipase inhibition, as well as antiadipogenic and lipolysis effects. CZME might be a promising source in the field of nutraceuticals. However, the active compounds that confer the antiobesity activities of CZME need to be identified.

• Proceedings of KHEA Conference
• /
• 2005.10a
• /
• pp.127-127
• /
• 2005

• Fibers and Polymers
• /
• v.2 no.3
• /
• pp.141-147
• /
• 2001

The effect of compositions of isophorone diisocyanate (IPDl)/4.4'-diphenylmethane diisocyalate (MDI) and polypropylene oxide diol (PPG, $M_w$: 3000)/1,4-butane diol (BD) on the properties of UV-cured polyurethane acrylate films based on 2-hydroxyethyl acrylate (HEA) was examined. UV-curable polyurethane acrylates were formulated from the prepolymer. trimethylol propane triacrylate (TMPTA) as a reactive diluent, and 1-hydroxycyclohexyl ketone (Irgacure 184) as a photoinitiator. Dynamic mechanical thermal properties and elastic properties of UV-cured polyurethane acrylates was fecund to depend on the chemical composition of IPDl/MDl and PPG/BD. As the BD content increased, the tensile storage modulus of all series samples increased significantly. The storage modulus increased in the order of samples A (IPDI based samples)> samples B (IPDI/MDl (7/3 molar ratio) based samples) > samples C (IPDI/MDl (5/5 molar ratio) based samples at the same composition. Two distinct louts modulus peaks for all samples are observed owing to the softs segment glass transition temperature ($T_gh$) and hard segment glass transition temperature ($T_gh$). The difference between $T_gh$, and $T_gh$, (Δ$T_g$) increases in the order of A > B > C at the same composition. In cycle test, the initial onset strain (%) was found to decrease with increasing BD content in PPG/BD and with increasing MDI content in IPDI/MDl.