• Korean Chemical Engineering Research
• /
• v.51 no.6
• /
• pp.692-699
• /
• 2013

In this study, isothermal (350, 375, 400, 425, 450, 500, $850^{\circ}C$) experiments were carried out using a custom-made thermobalance to analyze the thermal decomposition properties of refuse plastic fuel (RPF), which is to be used as a cofiring fuel with a sub-bituminous coal at commercial circulating fluidized bed (CFB) boiler in Korea. In isothermal pyrolysis results, no change in the reaction model was observed in the temperature range of $375{\sim}450^{\circ}C$ and it was revealed that the first order chemical reaction (F1) is the most suitable among 12 reaction models. The activation energy shows similar results irrespective of application of reaction model in that the activation energy was 39.44 kcal/mol and 36.96 kcal/mol when using Arrhenius equation and iso-conversional method ($0.5{\leq}X{\leq}0.9$) respectively. Mean-while, the devolatilization time ($t_{dev}$) according to particle size (d) of RPF could be expressed as $t_{dev}=10.38d^{2.88}$ at $850^{\circ}C$, operation temperature of CFB and for even distribution and oxidation of RPF in CFB boiler, we found that the relationship of average dispersion distance (x) and particle size was $x{\leq}1.58d^{1.44}$.

• Korean Chemical Engineering Research
• /
• v.55 no.4
• /
• pp.456-466
• /
• 2017

This work investigated the particle morphology change to difference in milling media in a metal based composite fabrication process using a stirred ball mill with ball behavior of DEM simulation. A simulation of the three dimensional motion of grinding media in the stirred ball mill for the research of grinding mechanism to clarify the force, kinetic energy, and medium velocity of grinding media were calculated. In addition, the rotational speed of the stirred ball mill was changed to the experimental conditions for the composite fabrication, and change of the input energy was also calculated while changing the ball material, the flow velocity, and the friction coefficient under the same conditions. As the rotating speed of the stirred ball mill increased, the impact energy between the grinding media to media, media to wall, and media and the stirrer increased quantitatively. Also, we could clearly analyze the change of the particle morphology under the same experimental conditions, and it was found that the ball behavior greatly influences in the particle morphology changes.

• Journal of Korean Ophthalmic Optics Society
• /
• v.6 no.1
• /
• pp.149-153
• /
• 2001

Three-dimensional thermoluminescence(TL) spectra of LiF: Mg, Cu, Na, Si TL material based on temperature, wavelength and intensity were measured and analyzed. The glow curves were obtained by integration of luminescence intensity for wavelength at each temperature, and various trapping parameters related to the trap formation were determined by analyzing these curves. Computerized glow curve deconvolution(CGCD) method which based on general order kinetics(GOK) model were used for the glow curve analysis. The glow curves of LiF:Mg, Cu, Na, Si TL material were deconvoluted to six isolated glow curves which have peak temperature at 333 K, 374 K, 426 K, 466 K, 483 K and 516 K, respectively. The 466 K main glow peak had an activation energy of 2.06 eV and a kinetic order of 1.05. This TL material was also found to have three recombination centers, 1.80 eV, 2.88 eV and 3.27 eV by TL spectra analysis based on Franck-Condon model. It showed that 2.88 eV is the dominant center, followed by 3.27 eV level, and 1.80 eV center is ascertained as emission center of this material even though its very weak emission intensity.

• Archives of Plastic Surgery
• /
• v.36 no.4
• /
• pp.432-436
• /
• 2009

Purpose: Negative pressure therapy has been used in various conditions to promote wound healing. It has also been used to secure a skin graft by improving microcirculation and improving tight adhesion between the graft and the recipient bed. To reduce post burn scar contracture and improve aesthetical result, many types of dermal substitutes have been invented and used widely. The goal of this study was evaluate usefulness of the VAC (Kinetic concepts Inc., San Antonio, TX) in improving the take rate and time to incorporation of Integra$^{(R)}$ in reconstruction of burn scar contracture. Methods: A retrospective study was performed from October, 2006 to December, 2008. The VAC was utilized for 11 patients. The average patient's age was 19.7 years (range 5 - 27) and average surface area was $785cm^2$ (range 24 - 1600). The burn scars were excised deep into normal subcutaneous tissue to achieve complete release of the scar, Integra$^{(R)}$ was sutured in place with skin staple와 Steri - strip$^{(R)}$. Then slit incisions were made on silicone sheet only with No.11 blade for effective drainage. The VAC was used as a bolster dressing over Integra$^{(R)}$. Negative - Pressure ranging from 100 to 125 mm Hg was applied to black polyurethane foam sponge trimmed to the appropriate wound size. An occlusive seal over the black polyurethane foam sponge was maintained by a combination of the occlusive dressing, OP - site$^{(R)}$. The VAC dressing changes were performed every 3 or 4 days until adequate incorporation was obtained. The neodermis appeared slightly yellow to orange color. When the Integra$^{(R)}$ deemed clinically incorporated, The VAC was removed and take was estimated with visual inspection. Very thin STSG(0.006 ~ 0.008 inches) was performed after silicone sheet removal. Result: The mean time for clinically assessed incorporation of Integra$^{(R)}$ was 10.00 days (range 9 - 12). The mean dressing change was 3.5 times until take was obtained. In All patients, Integra$^{(R)}$ had successful incorporation in tissue without serious complications. Conclusion: Integra$^{(R)}$ in combination with Vacuum - Assisted Closure(VAC) may be incorporated earlier than conventional dressing method.

• Korean Journal of Applied Biomechanics
• /
• v.17 no.4
• /
• pp.201-208
• /
• 2007

The purpose of this study is to compare 4 different body punch types(type 1: a punch using a shoulder, type 2: a punch using a waist, type 3: a punch using lower extremities, and type 4: a punch with elbows by your side at chest level) in horseback-riding stance and establish suitable teaching theory and method, which would be a useful reference to Taekwondo instructors on the spot(in Taekwondo dojangs all around Korea). Five exhibition players from Korean national Taekwondo exhibition team participated in this study. Each participant was asked to perform the four different types of punches and their kinematic and kinetic data were recorded with 7 vicon cameras(125Hz) and two force plates(AMTI, 1200Hz). We analyzed displacement, time, resultant center of body mass trajectory, velocity, trunk angular velocity, and ground reaction force(GRF) from each body segment in body punch and the result. I performed 1-way ANOVA(RM) for average values of each player after standardization and statistical significance was set as p<.05. was as the following ; First, they showed a tendency to take the body punch posture with the biggest motion at a shoulder and on descending order a waist and a knee. Second, a mean time for each body punch on ascending order 0.46sec. for type 2, 0.49sec for type 3, 0.50sec. for type 4, and 0.56sec. for type 1. Third, a mean resultant center of body mass trajectory for each body punch the longest 4.07cm for type 3 and the shortest 2.458cm for type 1. Fourth, a mean of maximal velocity of a fist strike was the fastest 5.99m/s for type 3, 5.93m/s for type 4, 5.67m/s for type 2, and 5.01m/s for type 1 on the descending order. Fifth, a mean of maximal trunk angular velocity of the fastest 495.6deg./sec. for type 4 and 337.7deg./sec. for type 1 on the descending order. Sixth, strongest value was type 3, 2 for anterior-posterior ground reaction force(left -54.89N, right 60.58N), type 4 for medial-lateral GRF(left 83.59N, right -80.12N), and type 3 for vertical GRF(left 341.79N, right 426.11N).

• Applied Chemistry for Engineering
• /
• v.1 no.2
• /
• pp.190-196
• /
• 1990

The biological active monomer, 1-(methacryloyloxymethyl)-5-fluorouracil(MAOMFU) was synthesized from 2, 4-bis(trimethylsilyloxy)-5-fluoropyrimidine. Poly(MAOMFU) poly(1-methacryloyloxymethyl-5-f1uorouracil-co-methyl methacrylate), and poly(MAOMFU-co-MMA) were also obtained by radical polymerization at $60^{\circ}C$. The monomer reactivity ratios, $r_1$ and $r_2$ were determined by $Kelen-T\ddot{u}d\ddot{o}s$ method ; $r_1(MAOMFU)=0.72$, and $r_2(MMA)=1.24$. These reactivity values imply that the copolymerization was mainly affected by the steric hindrance of MAOMFU. It was found from kinetic measurements that the rate constants of solvolysis are given as $6.42{\times}10^{-5}sec^{-1}$ and $7.40{\times}10^{-6}sec^{-6}$, respectively, for MAOMFU and poly(MAOMFU).

• Applied Biological Chemistry
• /
• v.38 no.2
• /
• pp.118-122
• /
• 1995

Escherichia Coli ornithine transcarbamylase is the enzyme which catalyzes the L-citrulline biosynthesis from L-ornithine and carbamyl phosphate. To facilitate the purification of enzyme which will be used for many biochemical studies such as structure and function relationships and catalytic mechanisms, the cloning and expression of E. coli argI gene for ornithine transcarbamylase was conducted. argI was amplified from genomic DNA of E. coli strain of $DH5{\alpha}$, by polymerization chain reaction (PCR) method. The amplified argI gene was ligated to the prokaryotic expression vector pKK223-3 and used for transformation of E. coli TB2 which was deficient of ornithine transcarbamylase. The over-produced enzyme by the tnansformant was purified by ammonium sulfate fractionation, heat denaturation and affinity chromatography. The result of SDS denaturation gel electrophoresis for the purified enzyme showed a single band of about 38 kDa of ornithine transcarbamylase. Kinetic data for the expressed enzyme gave almost the s?????? values as those of the wild type enzyme. The $k_{cat}$, of the enzyme was $1.0{\times}10^5min^{-1}$, and $K_ms$ for ornithine and carbamyl phosphate were 0.35 mM and 0.06 mM, respectively.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.15 no.4
• /
• pp.165-174
• /
• 2011

This research aims at the optimal constitution of sensors required to identify the structural shortcoming of roller-coaster. In this research we analyzed the dynamic characteristics of roller-coaster by three dimensional FE modelling, decided on the appropriate location and number of sensors through optimal transducer theory, abstracted the mathematical value of modal features before and after damage on the basis of optimally placed and numbered sensors. and then presented it as a primary information about the basic structure which would be applied to damage estimation. As a target structure, the roller-coater at Seoul Children's Grand Park was chosen and built as a model reduced by one twentieth in size. In order to consider the Kinetics features particular to the roller-coaster structure, we made an exact three-dimensional FE modelling for the model structure by means of Spline function. As for the proper location and number of sensors, it was done by applying EIM and EOT. We also estimated the damage from the combination of strength, flexibility, and model corelation after abstracting the value of modal features. Finally the optimal transducer theory presented here in this research was proved to be valid, and the structural damage was well identified through changes in strength and flexibility. As a result, we were able to present the optimal constitution of sensors needed for the analysis of dynamic characteristics and the development of techniques in dynamic characteristics, which would ultimately contribute to the development of health monitoring for roller-coaster.

• Korean Journal of Head & Neck Oncology
• /
• v.10 no.2
• /
• pp.200-205
• /
• 1994

Proliferating cell nuclear antgen(PCNA) plays an important role in DNA synthesis in nucleoli and is highly conserved non-histone nuclear protein composed of 261 amino acid. and is considered to correlated with the cells proliferative state, because it is synthesized particulary during the proliferative period of late Gland S-phase. Therefore, PCNA index meaningfully increases in the active or proliferative kinetic cells. By the use of recently developed monoclonal antibodies against PCNA, the immunohistochemical staining methods can make possible. These staining methods are the useful and productive one for ascertaining the cell's proliferating abillity. Moreover, immunohistochemical staining method with a antiPCNA antibody has particulrar advantages as follows. By means of these methods, we can stain the tissue that was already fixed in formalin or paraffin wax. We can see with naked eye that which cell is, where is differentiated through a microscope. Lastly, it maintains the whole tissue architecture and makes a search for the correlation. As we have seen above, the immunohistochemical staining methods for PCNA have been studied as an impotant factor that can find the cell proliferative kinetics in malignancy and biologic behavior of tumors. To investigate of the proliferative activity in thyroid nodule, Authors evaluated cell proliferative activity by immunostaing for PNCA in 45 pathologically confirmed solitary thyroid nodule. The results were as follows. 1) The benign nodules were 25 cases(Adenomatous Goiter: 20 cases, Follicular adenoma: 5 cases) and malignant nodules were 20 cases(Papillary Ca : 14 cases, Follicular Ca : 4 cases, Anaplastic Ca : 2 cases). 2) The Most prevalent age groups were 4th decade(11 cases), and the next group was 5th decade. 3) The average PCNA labelling indices were as follows. Adenomatous goiter(I6.9%), Follicular adenoma(37.6%), papillary Ca(26.3%), Follicular Ca(8.8%) and Anaplastic Ca(86.7%). There were no significant differences in benign(20.4) and malignant nodules (28.8%) except anaplastic Ca(p=0.3226). 4) When the average tumor size 2cm in papillary Ca, the PCNA indices were 26.0% (below 2cm) : 26.6% (above 2cm) (p=0.9642). The PCNA incidies were 23.9% (with lymphatic spread) : 28.7% (without lymphatic spread) (p=0.7056). There were no signlficant differences in the above cases. In conclusion, there were no significant differences in cell proliferative activity by staining for PCNA between benign and malignat nodules except anaplastic Ca.

• Applied Chemistry for Engineering
• /
• v.25 no.4
• /
• pp.430-436
• /
• 2014

Allura Red (AR) is a water-soluble harmful tar-based food colorant (FD & C Red 40). Batch adsorption studies were performed for the removal of AR using bituminous coal based granular activated carbon as adsorbent by varying the operation parameters such as adsorbent dosage, initial concentration, contact time and temperature. Experimental equilibrium adsorption data were analyzed by Langmuir, Freundlich and Temkin isotherms. The equilibrium process was described well by Freundlich isotherm. From determined separation factor ($R_L$), adsorption of AR by granular activated carbon could be employed as effective treatment method. Temkin parameter, B was determined to 1.62~3.288 J/mol indicating a physical adsorption process. By estimation of adsorption rate experimental data, the value of intraparticle diffusion rate constant ($k_m$) increased with the increasing adsorption temperature. The adsorption process were found to confirm to the pseudo second order model with good correlation. Thermodynamic parameters like change of free energy, enthalpy, and entropy were also calculated to predict the nature adsorption in the temperature range of 298~318 K. The negative Gibbs free energy change (${\Delta}G$ = -2.16~-6.55 kJ/mol) and the positive enthalpy change (${\Delta}H$ = + 23.29 kJ/mol) indicated the spontaneous and endothermic nature of the adsorption process, respectively.