• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2003.05a
• /
• pp.29-32
• /
• 2003

We introduce the subcategories IRe $l_{PR}$ (H), IRe $l_{PO}$ (H) and IRe $l_{E}$(H) of IRe $l_{R}$(H) and study their structures in a viewpoint of the topological universe introduced by L.D.Nel. In particular, the category IRe $l_{R}$(H)(resp. IRe $l_{P}$(H) and IRe $l_{E}$(H)) is a topological universe eve, Set. Moreover, we show that IRe $l_{E}$(H) has exponential objects.ial objects.

• The Korean Journal of Ceramics
• /
• v.2 no.3
• /
• pp.131-136
• /
• 1996

The electrical conductivity of polycrystalline TiO2 samples was measured over the temperature range 1000°-1400℃ and from 0.21 to 10-16 atm of oxygen. Based on the excellent fit observed between the theoretically derived relatin σ3=(Aσ+B)Po2-1/2+D'σ2 and the experimental conductivity data, the nonstoichimetric defect structure of TiO2 was rationalized in terms of a defect model involving quasi-free electrons and both singly and doubly ionized oxygen vacancies. The standard enthalpy of formation for the following defect reactions in TiO2. (a) OO={{{{ { 1} over {2 } }}O2(g)+VO+e'; Δ{{{{ { H}`_{o } ^{a } }}=5.15(eV) (b) OO={{{{ { 1} over {2 } }}O2(g)+VO+2e'; Δ{{{{ { H}`_{0 } ^{ a} }}=6.30(eV) (c) VO=VO+e'; Δ{{{{ { H}`_{0 } ^{a } }}=1.15(eV) were determined from the temperature dependence of A and B obtained from the above relation and from the experimental expression between the electron mobility and temperature. The electrical conductivity of TiO2 in air below approximately 950℃ appears, on the basis of this investigation, to be impurity controlled due to the presence of aluminum rather than intrinsic conduction.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.641-644
• /
• 2005

The aim of this research is to evaluate the relationship between the total effective moment $(M^E)$ and Bemoulli-Euler bending moment (M) when the ply orientations of UD CFRP in Piezoelectric Zirconate Titanate Composite Actuator (PZTCA) are changed. The obtained results as follows. Firstly, as the performance test results by the CFRP ply orientation, the performance of [0] and [90] were stable. However, while the performance of [+45] was suddenly decreased after 5 hours. Secondly, the change of $M^E$ by the CFRP ply orientation was evaluated. As the CFRP ply orientation was increased from [0] to [+60], the $M^E$ were gradually decreased. However, they became a little bit increased from [+60] to [90]. Finally, after the change of M by the CFRP ply orientation was evaluated, it was found that $M^E=2.2M$ was valid for just [0] and that there was a relationship between $M^E$ and M according to the ply orientation.

• Journal of Ecology and Environment
• /
• v.34 no.2
• /
• pp.223-235
• /
• 2011

Juncus effusus is mostly found in freshwater wetlands and is widely used for landscaping and creating artificial wetlands due to its high ecological value. J. effusus tends to dominate during the early stage (3-10 years) of the second succession in abandoned paddy fields. This study focused on the environmental characteristics of J. effusus to create habitat for an endangered species, Nannopya pygmaea, which lives in wetlands dominated by J. effusus. Considering the distribution of J. effusus and N. pygmaea, 63 quadrats at eight wetlands were investigated between May and June 2006 during the critically dry period. Fifty-three species from 28 families co-occurred with J. effusus, and Persicaria thunbergii was the most abundant (63.5%). The optimal ranges of distribution (ORD) for the water variables were water depth, -2 to 10 cm; dissolved oxygen, 0.99-3.55 mg/kg, conductivity (CON), 23.40-115.40 ${\mu}s/cm$, total dissolved solid, 12.53-57.60 mg/L; pH, 5.00-6.87; $K^+$, 0.11-1.46 mg/L; $Ca^{2+}$, 1.53-5.85 mg/L; $Na^+$, 3.16-7.47 mg/L; $Mg^{2+}$, 0.11-1.96 mg/L; $NO_3$-N, < 0.001-0.072 mg/L; $NH_4$-N, 0.005-0.097 mg/L; and $PO_4$-P, 0.006-0.047 mg/L. ORDs for the soil variables were water content, 1.05-2.96%; loss-on ignition method (LOI), 5.07-7.81%; CON, 23.70-59.70 ${\mu}s/cm$; pH, 4.40-5.16; extracted (e) $K^+$, 4.34-15.73 cmol/kg; $eCa^{2+}$, 31.56-191.56 cmol/kg; $eNa^+$, < 0.01-2.61 cmol/kg; eMg, 0.04-19.82 cmol/kg; $eNO_3$-N, 0.514-1.175 mg/kg; $eNH_4$-N, 0.033-0.974 mg/kg, $ePO_4$-P, 0.491-11.552 mg/kg; total nitrogen, 0.016-0.200%; and total carbon, 1.06-2.37%. The appearance of rush during early succession indicated relatively lower levels of these physicochemical parameters, and that ORDs should be maintained for the J. effusus community.

• Radiation Oncology Journal
• /
• v.8 no.1
• /
• pp.1-6
• /
• 1990

In the present study, a perfluorchemical emulsion (Fluosol-DA $20\%$) did not alter $D_o\;and\;D_q$ values on cell survival curve, indicating that the lack of a direct effect of Fluosol-DA $20\%$ on cellular radiosensitivity in vitro. The effect of Fluosol-DA $20\%$ injection in combination with carbogen breathing was determined on the hypoxic cell fraction in SCK tumors. The hypoxic cell fraction in control SCK tumors was 0.39. This value decreased to 0.05 when the mice were i.v. injected with 12 ml/kg of Fluosol-DA $20\%$ in a carbogen atomosphere. The measured mean and median $PO_2$ values with a microelectrode in the control tumors was 9 mmHg and 4 mmHg, respectively. The treatment of the SCK tumors in the host mice with injected Fluosol-DA $20\%$ in combination with carbogen breathing increased the mean and median $PO_2$ values to 67 mmHg and 62 mmHg, respectively. Using carbogen breathing alone caused a moderate increase of tumor $PO_2$. But Fluosol-DA $20\%$ injection alone caused little change $PO_2$ in the tumor. It was concluded that the combination of Fluosol-DA injection and carbogen breathing is an effective means to improve oxygenation of tumors.

• Korean Journal of Materials Research
• /
• v.22 no.7
• /
• pp.346-351
• /
• 2012

$Li_{1+x}Al_xTi_{2-x}(PO_4)_3$(LATP) is a promising solid electrolyte for all-solid-state Li ion batteries. In this study, LATP is prepared through a sol-gel method using relatively the inexpensive reagents $TiCl_4$. The thermal behavior, structural characteristics, fractured surface morphology, ion conductivity, and activation energy of the LATP sintered bodies are investigated by TG-DTA, X-ray diffraction, FE-SEM, and by an impedance method. A gelation powder was calcined at $500^{\circ}C$. A single crystalline phase of the $LiTi_2(PO_4)_3$(LTP) system was obtained at a calcination temperature above $650^{\circ}C$. The obtained powder was pelletized and sintered at $900^{\circ}C$ and $1000^{\circ}C$. The LTP sintered at $900{\sim}1000^{\circ}C$ for 6 h had a relatively low apparent density of 75~80%. The LATP(x = 0.3) pellet sintered at $900^{\circ}C$ for 6 h was denser than those sintered under other conditions and showed the highest ion conductivity of $4.50{\times}10^{-5}$ S/cm at room temperature. However, the ion conductivity of LATP (x = 0.3) sintered at $1000^{\circ}C$ decreased to $1.81{\times}10^{-5}$ S/cm, leading to Li volatilization and abnormal grain growth. For LATP sintered at $900^{\circ}C$ for 6 h, x = 0.3 shows the lowest activation energy of 0.42 eV in the temperature range of room temperature to $300^{\circ}C$.

• Transactions on Electrical and Electronic Materials
• /
• v.2 no.1
• /
• pp.12-15
• /
• 2001

Bi-2212 and Bi-2223 thin films are prepared by IBS(ion beam sputtering) technique. Three phases of Bi-2201, Bi-2212 and Bi-2223 appear as stable ones in spite of the conditions for thin film fabrication of Bi-2212 and Bi-2223 compositions, depending on substrate temperature (T $_{sub}$) and ozone pressure(PO$_3$). It is found out that these phases are limited within very narrow temperature.e.

• Korean Journal of Environmental Biology
• /
• v.24 no.3
• /
• pp.300-305
• /
• 2006

Jassa slatteryi was redescribed as a new record to Korean fauna, accompanied by the morphological account in comparison with Jassa falcata Montagu, 1808. This work was based on the specimens which were collected from the screw of the international trade ship, named Hanjin, anchored in Samcheon-po bay of the south coast of Korea in 2004.

• The Korean Journal of Ecology
• /
• v.14 no.3
• /
• pp.243-255
• /
• 1991

The vegetation of haenam peninsula(126 30e.l. and 34 30n.l ) was investigated from July, 1990 to 1991. the units of vegetatin were classified by the phytosociological method of broun- blanquet's. the forest vegetation was classified into 7 communities, sasa borealis-quercus acuta, cinnamomum japonicum, camellia japonica, rhododendron mucronulatum-pinus thunbergii, pinus densiflora community, torreya nucifera, chamaecyparis obtusa afforestatio, and the actual vegetation map was drawn in 1 : 50,00 scaie.

• Journal of applied mathematics & informatics
• /
• v.15 no.1_2
• /
• pp.159-172
• /
• 2004

A map is singular if each edge is on the same face on a surface (i.e., those have only one face on a surface). Because any map with loop is not colorable, all maps here are assumed to be loopless. In this paper po-vides the explicit expression of chromatic sum functions for rooted singular maps on the projective plane, the torus and the Klein bottle. From the explicit expression of chromatic sum functions of such maps, the explicit expression of enumerating functions of such maps are also derived.