• Imaging Science in Dentistry
• /
• v.37 no.1
• /
• pp.15-18
• /
• 2007

Purpose : Disc and condylar position were observed on MRIs of temporomandibular joint disorder patients and condylar position agreement between MRI and tranascranal radiography was evaluated. Materials and Methods MRI and transcranial radiographs of both TM joints from 67 patients with temporemandibular disorder were used. On MRI, the position and shape of disc and condylar position as anterior, middle, posterior was evaluated at medial, center, and lateral views. On transcranial radiographs, condylar position was evaluated using the shortest distance from condyle to fossa in anterior, superior, and posterior directions. Results. 1. On MRI, 96 joints (71.6%) of 134 had anterior disc dispalcement with reduction and 38 joints (28.4%) without reduction. 2. Fourteen (14.6%) of 96 reducible joints showed anterior condylar position, 19 (19.8%) showed central position, 63 joints (65.6%) showed posterior position. Two joints (5.3%) of 38 non-reducible joints showed anterior condylar position, while 9 (23.7%) showed central position, and 27 (71.1%)-posterior position. 3. In 85 joints (63.4%) of 134, the transcranial condylar position agreed with that of the central MRI view, 10 joints (7.5%) with that of medial, 16 joints (11.9%) with that of lateral, and 23 joints (17.2%) disagreed with that of MRI. Conclusion : On MRT, most oi the reducible and non-reducible joints showed posterior condylar position. Transcranial radiographs taken with machine designed for TMJ had better agreement of condylar position with that of MRI. Extremely narrow joint spaces or very posterior condylar positions observed on transcranial radiographs had a little more than fifty percent agreement with those of MRIs.

• Journal of the Chungcheong Mathematical Society
• /
• v.9 no.1
• /
• pp.69-76
• /
• 1996

We obtain some properties of reducible differential equations in the sense of Liapunov.

• Journal of the Korean Mathematical Society
• /
• v.13 no.1
• /
• pp.141-144
• /
• 1976

• The Mathematical Education
• /
• v.24 no.3
• /
• pp.17-18
• /
• 1986

• Bulletin of the Korean Mathematical Society
• /
• v.50 no.6
• /
• pp.2001-2011
• /
• 2013

Cho and Kim [4] have introduced the concept of the competition index of a digraph. Similarly, the competition index of an $n{\times}n$ Boolean matrix A is the smallest positive integer q such that $A^{q+i}(A^T)^{q+i}=A^{q+r+i}(A^T)^{q+r+i}$ for some positive integer r and every nonnegative integer i, where $A^T$ denotes the transpose of A. In this paper, we study the upper bound of the competition index of a Boolean matrix. Using the concept of Boolean rank, we determine the upper bound of the competition index of a nearly reducible Boolean matrix.

• Communications of the Korean Mathematical Society
• /
• v.25 no.2
• /
• pp.185-191
• /
• 2010

Srivastava noticed the existence of three additional complete triple hypergeometric functions $H_A$, $H_B$ and $H_C$ of the second order in the course of an extensive investigation of Lauricella's fourteen hypergeometric functions of three variables. In 2004, Rathie and Kim obtained four summation formulas containing a large number of very interesting reducible cases of Srivastava's triple hypergeometric series $H_A$ and $H_C$. Here we are also aiming at presenting two unified summation formulas (actually, including 62 ones) for some reducible cases of Srivastava's $H_C$ with the help of generalized Dixon's theorem and generalized Whipple's theorem on the sum of a $_3F_2$ obtained earlier by Lavoie et al.. Some special cases of our results are also considered.

• Kyungpook Mathematical Journal
• /
• v.52 no.2
• /
• pp.149-153
• /
• 2012

We show that the above lemma and its well-known refinement are valid, in a general setting, in non-commutative rings. Some interesting consequences are also observed.

• Journal of Soil and Groundwater Environment
• /
• v.21 no.6
• /
• pp.169-178
• /
• 2016

The Standards, Measurement and Testing Programme (SM&T-formerly BCR) extraction procedure was applied to fractionate Cr, Cu, Ni, Pb and Zn in 23 top soil samples into: (i) exchangeable phase; (ii) reducible phase; (iii) oxidisable(sulfides and organics bound) phase; and (iv) residual phase. Fractions of Cr and Ni were in the order of residual > oxidisable > reducible > exchangeable phase. The oxidisable phase was identified as dominant for Cu and Pb. Zn had the highest ratio of exchangeable phase in comparision to the other metals. The bioavailability and mobility were assessed to be the greatest for Zn, followed by a decreasing order of Pb, Cu, Ni and Cr. All metal average concentrations in topsoil samples was higher in industrial sites than in agricultural sites. Our results revealed higher concentrations in topsoil samples (0~15 cm) than in sub soils (15~30 cm, 30~60 cm) for most metals at six sites (No. 5, 6, 17, 19, 20, 23). The fractions of exchangeable, reducible ad oxidisable phases showed relatively high correlation with soil pH, Fe/Mn oxide concentrations and organic matter contents, respectively.

• Korean Journal of Ecology and Environment
• /
• v.38 no.3 s.113
• /
• pp.334-340
• /
• 2005

The chemical forms of Cd, Cu, Pb, and Zn were analysed by sequential extraction technique to evaluate the effects of drying and heating of dredged sediments from Lake Chungcho. The most abundant fraction of Cd, Cu, and Zn in the wet and untreated sediment was organic/sulfidic fraction that is state in reducing environment such as the bottom condition of Lake Chungcho, while Pb dominated in residual fraction. This means that the source of Cd, Cu, and Zn in the Chungcho lake sediment is related to the organic degradation and Pb to the erosion from surrounding rocks. With drying and oxidation by dredging, heating treatment, and disposal of the lake sediment, the chemical forms of studied metals changed greatly from organic/sulfidic fraction to adsorbed and reducible fractions which are more labile in oxygenated environment. Organic/sulfidic fraction of Cd, Cu and Pb in the wet sediment was transformed with drying and heating treatments to the labile ones like adsorbed and reducible fraction, but Zn to carbonate and reducible fraction. Heating of the sediment at $320^{\circ}C$ greatly increased the labile fraction of Cd and Cu, while that at $105^{\circ}C$ for Pb and Zn. It is believed that the increase in labile forms of heavy metals in the sediments by drying and heating is caused by the contact with oxygen during drying and heating and by the increase of pH of the pore water at the expense of organic/sulfidic fraction. It is concluded that the drying and oxidation currently used in the treatment of dredged sediment can increase labile forms of heavy metals in the sediment, and the potential of the metal availability from the sediment.

• Economic and Environmental Geology
• /
• v.36 no.1
• /
• pp.17-25
• /
• 2003

Researches were carried out to investigate the characteristics and concentration of heavy metal elements of stream water through Dongmyoung abandoned metal mine and soil adjacent to the mine. The pH range of water was 5.9∼7.1 that implies the water environment was acidic to neutral. The contents and distribution aspects of heavy metals in water samples varied with geochemical characteristics of element, but the concentration of heavy metals has the tendency of increase closer to the mine in general. The results of soil analysis show that total heavy metal concentration of agricultural soil near mine was far lower than those of ore tailing and dumping site. Therefore, the effects of the abandoned mine on stream water and agricultural products were supposed to be insignificant, particularly because the portion of absorbed carbonates and reducible fractions among total heavy metal concentration was relatively lower than the other. Since, however total heavy metal concentrations of mining site were relatively higher than those of adjacent region, there is a possibility of heavy metal difussion when the chemical environment of the site changes due to migration of surface and underground water. It is suggested that the preventive measures for water and soil pollution by the heavy metals would be considered around the region.