• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.5
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• pp.411-417
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• 2020

In this study, we introduce a Na β"-alumina composite thick film as a solid electrolyte, to reduce the resistance of electrolyte for a Na/S battery. An alumina/zirconia composite material was used to enhance the mechanical properties of the electrolyte. A solid electrolyte of about 40 ㎛ thick was successfully fabricated through the conversion and tape-casting methods. In order to investigate the effect of the surface treatment process of the solid electrolyte on the battery performance, the electrolyte was polished by dry and wet processes, respectively, and then the Na/S batteries were prepared for analyzing the battery characteristics. The battery with the dry process performed much better than the battery made with the wet process. As a result, the battery manufactured by the dry process showed excellent performance. Therefore, it is confirmed that the surface treatment process of the solid electrolyte has an important effect on the battery capacity and coulombic efficiency, as well as the interface reaction.

• Journal of the Korean Ceramic Society
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• v.53 no.6
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• pp.712-718
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• 2016

In this study, we investigate the effect of the$Li_3BO_3$ additive on the densification and ionic conductivity of garnet-type $Li_7La_3Zr_2O_{12}$ solid electrolytes for all-solid-state lithium batteries. We analyze their densification behavior with the addition of $Li_3BO_3$ in the range of 2-10 wt.% by dilatometer measurements and isothermal sintering. Dilatometry analysis reveals that the sintering of $Li_7La_3Zr_2O_{12}-Li_3BO_3$ composites is characterized by two stages, resulting in two peaks, which show a significant dependence on the $Li_3BO_3$ additive content, in the shrinkage rate curves. Sintered density and total ion conductivity of the system increases with increasing $Li_3BO_3$ content. After sintering at $1100^{\circ}C$ for 8 h, the $Li_7La_3Zr_2O_{12}-8$ wt.% $Li_3BO_3$ composite shows a total ionic conductivity of $1.61{\times}10^{-5}Scm^{-1}$, while that of the pure $Li_7La_3Zr_2O_{12}$ is only $5.98{\times}10^{-6}Scm^{-1}$.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.6
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• pp.581-586
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• 2008

The MEMS solid propellant thrusters have very low thrust level for applying to the propulsion system of micro/nano satellites or the side jet thruster of smart bombs. In this research, the fabrication possibility of planar type MEMS solid propellant thrusters that have enlarged burning surface area was examined and the safety of the structure of thruster during the firing test was confirmed. The performance of a micro igniter which is the key component of the MEMS solid propellant thruster was estimated by the ANSYS Icepak and evaluated by the experiment. Finally, the thrust was measured by the micro force sensor. The levels of thrust were 300, 600 mN in the case of K=15, 20.

• Journal of Plant Biotechnology
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• v.37 no.2
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• pp.228-235
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• 2010

The establishment of cell suspension culture and plant regeneration of the halophytic Leymus chinensis (Trin.) are described in this study for the first time. Callus induction solid medium containing Murashige and Shoog (MS) basic salt, $2.0\;mg\;l^{-1}$ 2,4-dichlorophenoxyacetic acid (2,4-D), and $5.0\;mg\;l^{-1}$ L-glutamic acid with $30.0\;g\;l^{-1}$ sucrose and $4.0\;g\;l^{-1}$ gelrite for solidification induced the highest rate of cell division in Type 1 callus among calli of various types. Liquid medium with the same hormone distribution was therefore, used for cell suspension culture from Type 1 callus. Over a 30 d suspension culture at 100 rpm, great amounts of biomass were accumulated, with 71.07% average daily increment and 22.32-fold total fresh weight increment. Comparison of before and after suspension culture, the distribution of different size callus pieces and the maintenance of callus type were basically unaltered, but a slight increase in relative water contents was observed. To induce the potential of plant regeneration, the directly transferring on plant regeneration solid medium containing MS basic salt, $0.2\;mg\;l^{-1}$ $\alpha$-naphthalene acetic acid (NAA), $2.0\;mg\;l^{-1}$ kinetin (Kn), and $2.0\;g\;l^{-1}$ casamino acid and indirectly transferring were simultaneously performed. Even now growth rates of suspension-derived callus on solid medium were approximately half of those of Type 1 callus, but faster somatic embryogenesis was observed. Rooting of all regenerated shoots was successfully performed on half-strength MS medium. All plants appeared phenotypically normal.

• Macromolecular Research
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• v.17 no.11
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• pp.856-862
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• 2009

This study examined the effects of liquid and solid additives on the morphological, mechanical and thermal insulating properties of rigid polyurethane foams (PUFs). The PUFs synthesized with tetramethylsilane (TEMS) as a liquid-type additive showed a smaller average cell size and lower thermal conductivity than those with the aerosil 200 and clay 30B as solid-type additives. When TEMS was added, the average cell size of the PUF became more uniform and finer due to the reduced surface tension of the polymer solution, which increased the nucleation rate and number of bubbles produced and reduced cell size. The PUFs with TEMS showed the highest closed cell contents among the PUFs prepared using TEMS, aerosil 200 and clay 30B. This suggests that the insulation properties of PUF can be determined by both the size of the cell structure and the amount of closed cell contents in the system. The compression and flexural strengths of the PUF increased slightly when the aerosil 200, clay 30B and TEMS were added compared those of the neat PUF. The reaction profiles of the PUFs showed a similar gel and tack tree time with the reaction time among the PUFs synthesized with three different additives and neat PUF. This suggests that the nucleating additives used in this study do not affect the bubble growth of the chemical reaction, and the additives may act as nucleating agents during the formation of PUF. From the above results of the cell size, thermal conductivity, closed cell contents and reaction profile of the PUFs, liquid-type nucleating agent, such as TEMS, is more effective in decreasing the thermal conductivity of the PUF than solid-type nucleating agent, such as aerosil 200 and clay 30B.

• Journal of Trauma and Injury
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• v.23 no.2
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• pp.57-62
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• 2010

Purpose: This study analyzed the characteristics of stable pelvic bone fractures with intra-abdominal solid organ injury. Methods: Medical records were retrospectively reviewed from January 2000 to December 2009 of patients with stable pelvic bone fractures. A stable pelvic bone fracture according to Young's classification is defined as a lateral compression type I and antero-posterior compression type I. Subjects were divided into two groups, one with (injured group) and one without (non-injured group) intra-abdominal solid organ injury, to evaluate the dependences of the characteristics on the presence of an intra-abdominal solid organ injury. Data including demographics, mechanism of injury, initial hemodynamic status, laboratory results, Revised Trauma Score (RTS), Abbreviated Injury Scale (AIS), Injury Severity Score (ISS), amount of transfusion, admission to intensive care unit (ICU), and mortality were analyzed. Results: The subjects were 128 patients with a mean age of 42 years old, of whom were 67 male patients (52.3%). The injured group had 21 patients(16.4%), and the most frequent injured solid organ was the liver. Traffic accident was the most common mechanism of injury and lateral compression was the most common type of fracture in all groups. Initial systolic blood pressure was lower in the injured group, and the ISS was greater in the injured group. Arterial pH was lower in the injured group, and shock within 24 hours after arrival at the emergency department was more frequent in the injured group. Transfused packed red blood cells within 24 hours were 8 patients(38.1%) in the injured group and 11 patients(10.3%) in the non-injured group. Conservative treatment was the most common therapeutic modality in all groups. Stay in the ICU was longer in the injured group, and three mortalities occurred. Conclusion: There is a need to decide on a diagnostic and therapeutic plan regarding the possibility of intra-abdominal solid organ injury for hemodynamically unstable patients with stable pelvic bone fractures and for patients with stable pelvic bone fractures along with multiple associated injuries.

• Journal of the Korean Electrochemical Society
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• v.25 no.3
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• pp.95-104
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• 2022

The development of non-flammable all-solid-state batteries (ASSLBs) has become a hot topic due to the known drawbacks of commercial lithium-ion batteries. As the possibility of applying sulfide solid electrolytes (SSEs) for electric vehicle batteries increases, efforts for the low-cost mass-production are actively underway. Until now, most studies have used high-energy mechanical milling, which is easy to control composition and impurities and can reduce the process time. Through this, various SSEs that exceed the Li⁺ conductivity of liquid electrolytes have been reported, and expectations for the realization of ASSLBs are growing. However, the high-energy mechanical milling method has disadvantages in obtaining the same physical properties when mass-produced, and in controlling the particle size or shape, so that physical properties deteriorate during the full process. On the other hand, wet chemical synthesis technology, which has advantages in mass production and low price, is still in the initial exploration stage. In this technology, SSEs are mainly manufactured through producing a particle-type, solution-type, or mixed-type precursor, but a clear understanding of the reaction mechanism hasn't been made yet. In this review, wet chemical synthesis technologies for SSEs are summarized regarding the reaction mechanism between the raw materials in the solvent.

• Korean Journal of Materials Research
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• v.13 no.3
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• pp.160-168
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• 2003

The co-firing processes for the supported type planar solid oxide fuel cell were investigated. A flat cell of $7.7${\times}$10.8\textrm{cm}^2$ was fabricated successfully by the co-firing process, in which green films were co-sintered in the forms of two layers of anode/electrolyte or of three layers of anode/electrolyte/cathode with gas distributor. A co-fired cell of two layers yielded a power of 200 ㎽/$\textrm{cm}^2$ at 608 ㎷. Its performance loss was mainly due to iR drop in the anodic gas distributor, which was attributed to poor contact between anodic gas distributor and current collector. The performance in the co-fired cell of three layers was much lower than that of two layers, which resulted from the large iR drop and activation overvoltage at the cathodic side. In the co-fired cell of two layers, the impedance analysis indicated that the performance decay during cell operation is due to both anode overvoltage and iR drop at anode side. Also the electrode reaction of the co-fired two layers' cell is considered to be controlled by activation overvoltage within the low current of 50 ㎃.

• Mycobiology
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• v.39 no.1
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• pp.20-25
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• 2011

Spores of Aspergillus sp. SU14 were treated repeatedly and sequentially with $Co^{60}$ ${\gamma}$-rays, ultraviolet irradiation, and N-methyl-N'-nitro-N-nitrosoguanidine. One selected mutant strain, Aspergillus sp. SU14-M15, produced cellulase in a yield 2.2-fold exceeding that of the wild type. Optimal conditions for the production of cellulase by the mutant fungal strain using solid-state fermentation were examined. The medium consisted of wheat-bran supplemented with 1% (w/w) urea or $NH_4Cl$, 1% (w/w) rice starch, 2.5 mM $MgCl_2$, and 0.05% (v/w) Tween 80. Optimal moisture content and initial pH was 50% (v/w) and 3.5, respectively, and optimal aeration area was 3/100 (inoculated wheat bran/container). The medium was inoculated with 25% 48 hr seeding culture and fermented at $35^{\circ}C$ for 3 days. The resulting cellulase yield was 8.5-fold more than that of the wild type strain grown on the basal wheat bran medium.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.121-124
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• 2007

Stacks of solid oxide fuel cell under 1kW max power were designed on planar type employing anode supported cell and metallic interconnects. The stacks composed of 3-cells, 8-cells, and 16-cells were fabricated by using single cell purchased from Indec, sealant and interconnect prepared at RIST. In performance test of the final 16-cells stacks, OCV was recorded to be 16.7 V. Peak power and power density were 1 kW, 0.77 $W/cm^{2}$ at $820^{\circ}C$, respectively. In addition, the long term degradation rate of the power exhibited 2.25 % in 500 h at $750^{\circ}C$.