• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.1
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• pp.37-42
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• 2016

In this study, we examined the burning rate of the uncured propellant (with and without a curing agent application) in order to inspect the process of the HTPB solid propellant. The burning rate of the uncured propellant, that did not contain the curing agent, was approximately 9.7 mm/s at 1000 psi. In relation to the curing time, the burning rate was constant. The propellant, with the curing agent application, was approximately 8.1 mm/s showed a tendency of slowing as it burned. When the cure reaction rate was low, in accordance to the time, there were small changes in burn rate. However, when the cure reaction rate was high, the difference in burning rate was increased. The burning rate of a fully-cured propellant was approximately 6.8 mm/s, which appeared to be the lowest in order.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.23 no.3
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• pp.1-10
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• 2010

Objective : Erysipelas is an acute inflammation caused by pyogenic bacteria. This mainly involves the upper part of dermis. It begins as erythematous patches with tenderness, followed by fever, headache, chills and fatigue etc. It may results in edema, obstruction of lymphatics and sepsis. So this experiment is carried out for test whether the Bojeasodok-um subtracted Scrophulariae Radix, Lasiosphaera seu Calvatia, Isatidis Radix added indigo Naturalis, Lithospermi Radix have an anti-inflammatory effect and have suppression effect on immunocyte in the state of inflammation which induced by Erysipelas. Method : Experimental animals made use of 4-5 week-age(weight 20-25g) ICR(male) mouse. In the breeding farm, the lighting time was controlled from 7:00 am till 7:00 pm, the temperature was controlled So we concluded that BS is prospected as an anti-inflammatory agent to cure inflammation induced bywithin 18-23$23^{\circ}C$ and water and food were not limited.The freezing lyophilization powder which were extracted from Bojesodok-Um divided low dose group(200mg/kg-BSL) and high dose group(500mg/kg-BSH) and after melting in water, it was orally administered to the mouse. Compared with inflammation induced group which were induced by triggering-inflammation reagent Carageenan and Zymosan and normal contrast group, we measured the edema decrement effect,macrophage and spleen cell activation. Result : 1. BS has suppress inflammatory reaction induced by Carageenan. 2. BS has suppress increasing activation of abdominal cavity macrophage in the Carageenan and Zymosan induced inflammation. 3. BS has suppress increasing activation of spleen cell in the Carageenan and Zymosan induced inflammation. Based on the above result, BS was improved its suppression effect to the inflammatory reaction through the suppression of spleen cell and macrophage activation. So we concluded that BS is prospected as an anti-inflammatory agent to cure inflammation induced by Erysipelas.

• Journal of Sasang Constitutional Medicine
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• v.12 no.2
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• pp.171-183
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• 2000

1. Back ground and purpose An experimental study has done to examine the effect of defense and cure gastric mucasal damage of Mokdan-pijihwang-tang. 2. Methods Mice had intragastric injected with MJ extract before indomethacin treatment which induces homorrhage infarct and erosion artificially. Degree of lipid peroxidation, general morphology, change of mucous cell, the distribution of PNA, ICAM and distribution of apoptotic cell were objected. (Abbreviation) MJ : Mokdanpijihwang-tang, PNA : Peanut Agglutinin, ICAM : Intercellular Adhesion Molecule 3 Results 1) The degree of lipid peroxidation in INDO-group had increased conspicuously than control group. But the degree of lipid peroxidation in MJ-group had decreased than INDO-group and these decline had probability. 2) After indomethacin treatment, hemorrhage infarct and erosion had increased in stomach body. But in MJ-group, the configuration is normal, except the group intragastric injected with MJ extract at hour 24 before indomethacin treatment. 3) Surface mucous cell and neck mucous had disappeared in INDO-group. But in MJ-group tormal distribution had shown like control group except the group intragastric injected with MJ extract at hour 24 before indomethacin treatment. 4) PNA positive reaction had not shown in INDO-group. But medium PNA positive reaction had shown In Mj-group. 5) ICAM positive reacted cell had shown in INDO-group. The decrease of ICAM positive cell were shown than INDO-group. 6) A number of apoptotic cell was distributed in hemorrhagic erosion. A few number of apoptotic cell was distributed in MJ-group except some surface mucous. 4. Conclusion These results suggest that MJ has an effect on cure of gastric mucosal damage.

• Korean Journal of Materials Research
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• v.2 no.3
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• pp.191-196
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• 1992

The new epoxy resin, diglycidyl ether of bisphenol A(DGEBA)/4, 4'-methylene dianiline (MDA)/succinonitrile system, containing the reactive additive succionitrile was investigated through the impact test and the stress-strain test on the basis of the behavior of cure reaction and the cure mechanism. The new epoxy resin system, having the different succinonitrile contents, were cured at $80^{\circ}C$for 1.5 hour and then in order to cure completely at $150^{\circ}C$ for 1 hour. It was shown that as the succinonitrile content increased, impact strength was gradually increased, tensile strength was decreased, almost constantly Young's modulus was sustained and elongation was increased until the succinonitrile content was increased to 10phr, and then decreased. From the experimental results, it can be concluded that the chemical bonding length between the main chains was extended by adding the reactive additive succinonitrile. It was also found that the flexibility of epoxy resin was improved by adding the succinonitrile.

• Korean Journal of Materials Research
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• v.2 no.4
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• pp.257-262
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• 1992

The cure kinetics of a diglycidyl ether of bisphenol A (DGEBA) with 4, 4'-methylene dianiline (MDA) added succinonitrile was studied through the dynamic run method by applying the data to the Kissinger equation which analyses the effect of the heating rate on the temperature at maximum reaction rate using Differential Scanning Calorimetry (DSC) analyzer in the range of 3$0^{\circ}C$-35$0^{\circ}C$. In the DGEBA/MDA system with SN, the activation energy ($E_a$) and the pre-exponential factor (A) were calculated. From these results, the rate constants (k) were obtained according to the different SN contents.

• Bulletin of the Korean Chemical Society
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• v.30 no.2
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• pp.334-338
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• 2009

Trifunctional epoxy resin triglycidyl paraaminophenol (TGPAP)/$CaCO_3$ nanocomposites were prepared using the melt blending method. The effects of nano-$CaCO_3$ content on the thermal behaviors, such as cure behavior, glass transition temperature ($T_g$), thermal stability, and the coefficient of thermal extension (CTE), were investigated by several techniques. Differential scanning calorimetry (DSC) results indicated that the cure reaction of the TGPAP epoxy resin was accelerated with the addition of nano-$CaCO_3$. When the nano-$CaCO_3$ content was increased, the $T_g$ of the TGPAP/$CaCO_3$ nanocomposites did not obviously change, whereas the crosslinking density was linearly increased. The nanocomposites showed a higher thermal stability than that of the neat epoxy resin. This result could be attributed to the increased surface contact area between the nano-$CaCO_3$ particles and the epoxy matrix, as well as the high crosslinking density in the TGPAP/$CaCO_3$ nanocomposites. The CTE of the nanocomposites in the rubbery region was significantly decreased as the nano-$CaCO_3$ content was increased.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.6
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• pp.827-834
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• 2011

Epoxy/graphite/expanded graphite composites have been prepared in various weight ratios and thermal degradation and electrical properties were estimated in order to use for the bipolar plate materials in PEMFC. Thermogravimetric analysis (TGA) showed that the epoxy/graphite system cured by a curing agent GX-533 was most proper because its weight loss until $80^{\circ}C$ at which PEMFC would be operated was 0.3 wt%, and differential scanning calorimetry (DSC) analysis showed its cure temperature would be sufficient at $80^{\circ}C$. The activation energy for the cure reaction was 132.0 kJ/mol and the pre-exponential factor was $1.76{\times}10^{17}min^{-1}$. Electrical conductivity on the surface of the bipolar plate prepared under a pressure of 200 $kgf/cm^2$ was increased from 4 to 25 $S/cm^2$ by increasing expanded graphite (EG) content from 50 phr to 90 phr. The percolation threshold was initiated around 75 phr and the corrosion rate at 80 phr was 1.903 $uA/cm^2$.

• The Journal of Internal Korean Medicine
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• v.22 no.3
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• pp.353-360
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• 2001

Objectives: Recently, it was known that the major cause of hepatitis is apoptosis reaction mediated by Fas-FasL. Since Artemisia Capillaris Fructus has long been applied to cure the jaundice in oriental medicine. Therefore, this study was carried out to examine the effect of fractions of Artemisia Capillaris Fructus on Fas-FasL-mediated apoptosis in hepatocytes. Methods: This study employed propidium iodide negative cell count assay and some the other biochemical assays. Results : This study confirms that hepatitis has been occured by apoptosis mediated by Fas-FasL in cultured hepatocyte and fractions of Artemisia Capillaris Fructus restrain apoptosis induced Fas-FasL. Conclusions : Water-extracted fraction, methanol extracts, ether-soluble fraction, and buthanol-soluble fractions of Artemisia Capillaris Fructus restrain Fas-FasL-mediated apoptosis in hepatocyte. Silica gel chromatograph of Buthanol-soluble fraction of Artemisia Capillaris Fructus restrain Fas-FasL-mediated apoptosis in hepatocyte. Artemisia Capillaris Fructus could be applied to cure hepatitis.

• KSBB Journal
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• v.26 no.3
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• pp.193-198
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• 2011

Polyester was prepared through the esterification reaction between watsepaper liquefied by ethylene glycol and carboxylic acid. Liquefaction was carried out at the previously determined condition of 100 minutes, $160^{\circ}C$, and 3% sulfuric acid, and the hydroxyl value of the liquefied product was 411 mg KOH/g. In order to remove bubbles produced during the curing step, the method to introduce a slight nitrogen stream into reaction vessel and/or the method to preheat a polyester film at $85^{\circ}C$ before curing step were used alone or in combination. But if curing temperature was $130^{\circ}C$, simple method to cure a film for 5 hours at $130^{\circ}C$ without using both methods was found to be most effective. The polyesters prepared with various carboxylic acids showed significant different physical properties, and maleic acid was best among them. Also, the effect of reaction time and temperature, C/H (carboxyl group/hydroxyl group) ratio, and type of additive on the crosslinkage of polyester was investigated. Lithium hydroxide or citric acid as additive was used to enhance the crosslinkage of polyester and citric acid was proved to be much more effective than lithium hydroxide. The effect of reaction temperature on the crosslinkage was marginal, but the crosslinkage decreased above $130^{\circ}C$. The crosslinkage was 86% when the polyester was prepared at an optimum condition such as $130^{\circ}C$ and 15 minutes of reaction condition, 1.5 of C/H ratio, $130^{\circ}C$ and 5 hours of curing condition, and 10% addition of citric acid.

• Polymer(Korea)
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• v.34 no.5
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• pp.469-473
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• 2010

The curing mechanism and characteristics of UV curable acrylate resins were studied using Photo-DSC, FTIR, and Raman spectroscopy. Effects of chemical structures of acrylate, numbers of functional group, and UV intensity on curing kinetics were investigated with Photo-DSC. FTIR and Raman spectroscopy has been used to understand curing mechanisms and reaction conversion. In order to investigate the effect of oxygen on the photo-curing reaction, the curing process was compared between the acrylate and thiol-ene resins. The reaction conversion was found to be less than 80% for acrylate resins. The photo-curing reaction of the acrylate resin could not proceed to the end because of oxygen which acts as a reaction inhibitor while the thiol-ene resin was hardly affected from oxygen during the curing process.