• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.25 no.6
• /
• pp.426-430
• /
• 2012

The properties of green sheet were investigated in order to understanding an effects of organic solvent mixture ratio for solid oxide fuel cells fabrication. The purpose of this work is to optimize the slurry condition using the design of experiment to improve green sheet properties. The elongation increased with increasing amount of binder and solvent. With increasing amount of solvent, the air permeability increased but the tensile strength decreased. The best properties of the green sheet appeared amount of the binder 17 wt%, solvent 35 wt% and powder 48 wt%. The optimum condition of green and sintered density for solid oxide fuel cells fabrication was obtained in the sample pressured at 800 $kgf/cm^2$.

• IMMUNE NETWORK
• /
• v.8 no.2
• /
• pp.39-45
• /
• 2008

Background: Down regulation of major histocompatibility complex class II transactivator (CIITA) has been identified as a major factor of immunosuppression in sepsis and the level of CIITA expression inversely correlates with the degree of severity. However, it has not been fully elucidated whether the lower expression of CIITA is a cause of disease process or a just associated sign. Here we determined whether the CIITA deficiency decreased survival rate using murine sepsis model. Methods: Major histocompatibility complex class II (MHC-II) deficient, CIITA deficient and wild type B6 mice were subjected to cecal ligation puncture (CLP) surgery. CIITA and recombination activation gene (RAG)-1 double deficient mice were generated to test the role of lymphocytes in CIITA-associated sepsis progression. Results: Sepsis mortality was enhanced in CIITA deficient mice, not by impaired bacterial clearance resulted from CD4 T cell depletion, but hyper-inflammatory response such as excessive release of a pro-inflammatory cytokine, high-mobility group box 1 (HMGB1). Conclusion: Our results demonstrate that CIITA deficiency affects the course of sepsis via the unexpected function of CIITA, regulation of cytokine release.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.24 no.2
• /
• pp.167-175
• /
• 2011

The purpose of this study is to examine the impact that change in speed and modeling methods has on maglevs' runnability. The study constructed equations of motion on 4-DOF, 6DOF, and 10-DOF vehicles respectively and carried out numerical analysis, applying 4th Runge Kutta method, in order to run six different model maglev as changing the vehicles speed on the same bridge that had 2000 to 1 deflection. The analysis revealed that maglev's runnability improved as speed was lower and the specific model had higher number of bogey and EMS.

• Journal of Information Display
• /
• v.4 no.2
• /
• pp.35-42
• /
• 2003

The field emission and luminescent properties of carbon nanotubes (CNTs) that were straightened by argon ion irradiation were investigated. Argon ion irradiation permanently straightened both as-grown and screen-printed CNTs (SP-CNTs) in the presence of a strong electric field. The straightening process enhanced the emission properties of as-grown CNT films by showing a decrease in turn-on field, an increase in total emission current, and a stable emission. Recurring problems associated with SP-CNTs, such as bent or/and buried CNTs and the degradation in binder-residue-induced emission, were improved by the permanent straightening of CNTs and protruding CNTs from binders by the irradiation treatment, in addition to its surface cleaning effect. Furthermore, we confirmed that the number of emission sites increases by observing the luminescent properties of CNT films after the straightening. These findings here suggest that ion irradiation treatment is an effective method for achieving uniform field emission and to reduce the electrical aging time.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.20 no.6
• /
• pp.496-501
• /
• 2007

In order to enhance sintering characteristics on the $ZnO-Pr_6O_{11}$ based multilayer chip varistors (MLVs), a response surface analysis using central composite design method were carried out. As a result, varistor voltage($V_{1mA}$), nonlinear coefficient ($\alpha$), leakage current ($I_L$) and capacitance (C) were considered to be mainly affected by sintered temperature and holding time. MLVs sintered at $1200^{\circ}C$ and above $1200^{\circ}C$ revealed poor electrical characteristics, possibly due to the reaction between electrode materials(Pd) and $ZnO-Pr_6O_{11}$ based ceramics. On the sintering temperature range $1150{\sim}1175^{\circ}C$, nonlinear coefficient ($\alpha$) and leakage current ($I_L$) were shown to be $60{\sim}69$ and below $0.3{\mu}A$, respectively. In particular, MLVs sintered at $1175^{\circ}C$, 1.5 hr and $2^{\circ}C/hr$ (cooling speed) showed stable ESD(Electrical Static Discharge) characteristics under the condition of 10 times at 8 Kv with deviation varistor voltage, and deviation nonlinear coefficient were 0.3% and 0.33% (at positive), 0.55% (at negative), respectively.

• Environmental Engineering Research
• /
• v.23 no.3
• /
• pp.323-329
• /
• 2018

The municipal solid waste (MSW) management system in one of the Class II Indian cities i.e. Rishikesh was studied and analysed to identify the key issues in solid waste management in the city. A total of 329 solid waste samples from 47 households were collected to characterize the household solid waste (HSW). The average (HSW) generation rate was 0.26 kg/c/d and it was composed of organic waste (57.3%), plastics (14%), paper (10.9%), and glass and ceramic (1.3%) and other materials (16.5%). There was an inverse relationship between household waste generation rate and family size (p < 0.05). The MSW management system practiced in Rishikesh is unsound. There is no waste segregation at source, no provisions of composting and no recycling by formal sector. The collection and transportation of waste is inadequate and inappropriate. Collected waste is dumped in open dumping site without scientific management. Following are some recommendations for developing a sustainable solid waste management system in Rishikesh city: (1) sensitize people for segregation at source; (2) promote reduction, reuse and recycling of wastes; (3) promote community based composting; (4) provision for 100% door to door collection and; (5) formalize the informal sectors such as rag pickers and recycling industries.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.22 no.6
• /
• pp.495-500
• /
• 2009

The ceramic($BaTiO_3$)-polymer(epoxy) composites have been widely investigated as dielectric materials for embedded capacitors in printed circuit boards (PCBs). The dielectric properties of $BaTiO_3$/epoxy composites prepared using the agglomerated $BaTiO_3$ particles were investigated in the present study. The dielectric constants of the composites prepared using the agglomerated $BaTiO_3$ particles were about 2 times higher than those of the composites with the dispersed $BaTiO_3$ particles. The insulation resistance of the composites prepared using the agglomerated $BaTiO_3$ particles were lower than those of the composites with dispersed $BaTiO_3$ particles. As a result, there is tradeoff between high dielectric constant and insulation resistance in the $BaTiO_3$/epoxy composites. So it is important to select proper agglomerated or dispersed $BaTiO_3$ particles in accordance with needs.

• Textile Coloration and Finishing
• /
• v.7 no.4
• /
• pp.74-86
• /
• 1995

Antibacterial and deodorization properties of silk fabrics dyed with Sappan wood are investigated by Halo, Shake flask, Bioassay and Detection column methods.The results are obtained as follows; 1. Although K/S values increase with Al mordant and concentrate concentrations, these are decreased in 10% Al mordant concentration in case of 4mlg dye concentration. 2. Reduction ratios of bacteria increase with K/S values in various tests. 3. When undyed silk fabrics are treated with Al mordant, reduction ratios of bacteria are not varied with Al mordant concentrations. 4. Deodorization property of Al pre-mordanted dyeing silk fabrics is better than one of unmordanted dyeing and raw silk fabrics. 5. Antibacterial properties of Cu and Cr mordanted dyeing fabrics are better than ones of the dyeing fabrics treated with the other mordants. 6. Natural dyes extracted from Sappan wood show the good antibacterial and deodorization properties, and colorant among various components contained in Sappan wood has a excellent antibacterial and deodorization properties.

• Journal of Digestive Cancer Research
• /
• v.4 no.2
• /
• pp.99-106
• /
• 2016

Minimally invasive surgery for gastric cancer has increased in popularity during the last two decades mainly in the Asia for patients with early-stage cancer. Nevertheless, the development of laparoscopic surgery for gastric cancers in the Western world has been slow because of the advanced stage at diagnosis for which LG is not yet considered an acceptable alternative to standard open surgery. RAG has been reported as a safe alternative to conventional surgery for treating of early gastric carcinoma. We assess the current status of robotic surgery in the treatment of gastric cancer focusing on the technical details, postoperative outcome, oncological considerations and future perspectives. In gastrectomy the biggest advantage of the robotic approach is the ease and reproducibility of lymphadenectomy. Reports also show that even the intra corporeal digestive restoration is facilitated by use of the robotic approach, particularly following TG. Additionally, the accuracy of robotic dissection is confirmed by decreased blood loss in comparison to conventional laparoscopy. The learning curve and technical reproducibility also appear to be shorter with robotic surgery and, consequently, robotics can help to standardize and diffuse minimally invasive surgery in the treatment of gastric cancer. While published reports have shown no significant differences in surgical morbidity, mortality, or oncological adequacy between robot-assisted and conventional gastrectomy. There are some advantages in terms of postoperative recovery of patients after robotic surgery. More studies are needed to assess the true indications and oncological effectiveness of robotic use in the treatment of gastric carcinoma.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.22 no.8
• /
• pp.665-670
• /
• 2009

Lead-free piezoelectric ($Na_{1/2}K_{1/2}$)$NbO_3$ ceramics doped with CuO and $MnO_2$ were fabricated using the conventional oxide-mixing technique. With increasing content of CuO and $MnO_2$, the dielectric constant(${\varepsilon}_{33}$) and mechanical quality factor($Q_m$) value increased, while electromechanical coupling factor($K_p$) and piezoelectric constant($d_{33}$) decreased. The piezoelectric and dielectric properties ($Na_{1/2}K_{1/2}$)$NbO_3$ ceramics doped with CuO 2.461 wt% and $MnO_2$ 0.538 wt% at sintered temperature $1050\;^{\circ}C$ were attained ${\varepsilon}_{33}$ = 403, $K_p$ = 15, $Q_m$ = 122 and $d_{33}$ = 36 pC/N. Based on response surface methodology results using design of experiment, it was concluded that ($Na_{1/2}K_{1/2}$)$NbO_3$ doped with CuO 0.477 wt% and $MnO_2$ 0.269 wt% has possibility composition of being used for piezoelectric transformer.