• Korean Journal of Soil Science and Fertilizer
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• v.19 no.4
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• pp.307-314
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• 1986

Cu(II) binding mechanisms with water soluble organic fractions (WSOF) extracted from an agricultural soil (W), a soil treated with sludge for 6 years ($WS_6$), a sludge-soil mixture incubated for one week ($WS_1$), and sewage sludge (SS) were studied by electron spin resonance (ESR) spectroscopy and potentiometric titrations. Cu(II)-WSOF complexes produced $g_{11}$ values which were larger than $g_{\perp}$ values, indicating that the coordination of Cu(II) complex was an elongated octahedron. At liquid $N_2$ temperature (77K), the Cu(II)-W complex showed an anisotropic ESR spectrum while the Cu(II)-SS complex showed an isotropic spectrum. These spectral results suggest that the oxygen donor ligands of W may form relatively strong bonds with $Cu^{2+}$ due to extensive chelation while ligands of SS may form little or no chelate bonds with $Cu^{2+}$. The ESR spectra of Cu(II)-SS complex also suggest that each of four in-plane ligands (e.g., $COO^-$, $H_2O$, $Cl^-$, etc.) may act independently as monodentate ligands. Oxygen donor ligands such as aromatic carboxyl groups were probably the major Cu(II) binding sites in W. Sulfonate, aliphatic carboxyl group, and N-containing ligands were probably the major binding sites in SS at pH 5. The Cu(II) complexation with N-containing groups increased as sludge was added to the soil. Much higher (6x) pyridine concentrations were required to displace W from Cu(II)-W complex as compared to the Cu(II)-SS complex.

• The Journal of the Korean dental association
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• v.50 no.4
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• pp.203-210
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• 2012

Objective: The aim of this study was to investigate the incidence of the C-shaped canal of permanent mandibular second molar (PMSM) in Korean sub-population using Cone-Beam CT (CBCT) data and analyze the types of C-shaped canal. Materials & Methods: The protocol for this study was approved by the Institutional Review Board at the Pusan National University Hospital (E-2011039). Among the CBCT images taken of patients who visited the St. Bennedict Dental Hospital (Busan, Korea) from May 2008 to April 2011 for implant surgery and surgical removal of impacted teeth, high-quality CBCTs from 705 patients (361 male and 342 female) were screened and 607 PMSMs of 383 patients were evaluated retrospectively. All PMSMs were anatomically analyzed in detail by using image viewer software (EasyDent; Vatech). PMSMs were evaluated in the axial plane to investigate the shape of root and canals. The C-shaped canals were classified into five types. The total incidence, gender ratio, bilateral and unilateral appearance. and the correlation between right-side and left-side occurrences of C-shaped PMSMs were computed and compared statistically using the chi-square test. Results: Among the 607 PMSMs of 383 CBCTs of 187 females and 196 males, 198 PMSMs(32.6%) had C-shaped root and 158 PMSMs(26.0%) had C-shaped canals. The shape of C-shaped root canals at the furcalion level did not have significant change at the level of mid root (P<0.0001). Female had more prevalence of C-shaped root canals than male (P<0.0001). The prevalence of bilateral occurrence of C-shaped root canals was higher than unilateral occurrence. Conclusions: The occurrence of C-shaped PMSMs among a Korean population was 32.6% and was higher than other countries and ethnicities. Understanding the prevalence of PMSMs with a C-shaped root and/or canal in a Korean population may be useful for successful endodontic treatments.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.10
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• pp.1455-1459
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• 2003

A $2{\times}3$ factorial design was used to study the impact of rearing systems, individual (I) vs. group (G) and different levels of milk/skim milk feeding (three schedules, F1, F2 and F3) on performance of crossbred (Bos indicus ${\times}$ Bos taurus) calves. Six calves (three from each sex) were taken in each group on the basis of their birth weight. All the calves were fed colostrum for three days and thereafter, were allotted to three different milk feeding schedules (F), i.e. milk fed upto 8 weeks of age (F1), milk upto 4 weeks followed by 50% (F2) and 100% (F3) replacement of milk with skim milk in the next 4 weeks. Calf starter and cereal green fodder were fed ad libitum to all the calves beginning from second week of age. A digestibility trial was conducted at 15th week of age to assess nutrient utilization during postweaning period. The digestibilty of dry matter (DM), organic matter, total carbohydrate, ether extract and crude protein (CP) were nonsignificant between the rearing systems and the feeding schedules. There was significantly higher digestibility of NDF and ADF in G than I and in F3 than F1 and F2. The concentration CP and total digestible nutrients of the diet ranged from 17.18 to 17.75% and 66.32 to 70.14%, respectively. The DM intake (kg/100 kg body weight) ranged from 1.74 to 2.14 kg during 0 to 8 weeks and 3.19 to 3.41 kg during 0 to 14 weeks of age. The effects during postweaning phase (9-14 weeks of age) showed increased performance in group housed calves compared to individually housed ones with a superior average daily gain (590 vs. 443 g) and dry matter intake (1.79 vs. 1.64 kg). Above all, replacement of milk with skim milk at 50% level after 4th week followed by complete removal after 6th week of age (F2) seemed to suit better in coping with immediate energy starvation due to sole feeding of skim milk (F3) and they performed the best under group housed system of rearing.

• The Journal of Korean Academy of Prosthodontics
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• v.17 no.1
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• pp.7-21
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• 1979

This investigation was to analyse normal protrusive and lateral condylar pantographic records written on the sagittal plane and to study components of Fisher's angle and their interrelations. The purpose of this study was limited to (1) discussing the significance of sagittal pantographic record in diagnosis of occlusal disease and(2) basing for reasoning validity of measuring Fisher's angle which has been reported so far. As a result followings were concluded. 1. In each protrusive and lateral condylar movement path, five complicate factors such as initial straightness, distributed simple sigmoid type, simple curvature, initial tiny protruding convexity and tiny repeated sigmoid patterns were noted. Generally each condylar movement path was composed of two to three of these factors. 2. The distribution of positional interrelations of protrusive and lateral condylar paths could be divided into five categories; (a) protrusive-upper, (b) completely coinciding, (c) partially initial coinciding, (d) partially inverted crossing, and (e) completely inverting. Among these, protrusive path-upper positioned condyles were prevailed (79.2%). 3. The distribution of interrelations of protrusive and lateral condylar paths could be devided into five categories according to their distances in the course of movement. Among these, opening (95.8%) and paralleling (66.7%) were prevailing. 4. The involved number of characteristic heterogenous patterns of five categories in protrusive and lateral condylar movement recording relations at one simultaneous recordings was limited to three. However, in case of homogeneous patterns were repeated, usually three to four were included. 5. The maximum distance between protrusive and lateral condylar paths was 1.45mm at the location of 4mm advanced position from centric relation point and 3.90mm at the location of protrusive movement terminal. 6. It seemed to be that ,pantographic records should be consulted other clinical symptoms in order to make certain occlusion diagnosis. 7. At the present moment of investigation, expressing Fisher's angle as a degree revealed a lack due to inherent complexity of protrusive and lateral condylar movement paths. 8. The typical pattern of protrusive and lateral condylar paths written on a pantographic sagittal plate might be described as follows; (a) protrusive condylar path should be positioned upwardly, (b) both mainly be simple curvature, (c) interrelations mainly be opening or paralleling. 9. The mean amounts of separation between protrusive and lateral condylar movement path were $0.75{\pm}0.46$ at 4mm advanced location from centric relation and $1.74{\pm}0.64mm$ at the location of protrusive path terminal.

• Journal of Dental Rehabilitation and Applied Science
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• v.17 no.4
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• pp.245-256
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• 2001

The purpose of this study is to analyze the mechanical stress and displacement on the jaws during the simulated bilateral clenching task on the three-dimensional finite element model of the dentated skull with unilateral molar loss. For this study, the computed tomography(G.E.8800 Quick, USA) was used to scan the total length of human skull in the frontal plane at 2.0mm intervals. The fully assembled finite element model consists of the articular disc, maxilla, mandible, teeth, periodontal ligament and cranium. The FE model was used to simulate the bilateral clenching in intercuspal position. The loading condition was the force of the masseter muscle exerted on the mandible as reported by Korioth et al. degrees of freedom of the zygomatic region where the masseter muscle is attached were fixed as restraints. In order to reflect the actual action of the muscles force, the displacement of the region was attached where the muscle is connected to the temporal bone and restraint conditions were given values identical to values at the attachment region of the masticatory muscle but with the opposite direction of the reaction from when the muscle force is acted on the mandible. Although the mandible generally has higher displacement and von Mises stress than the maxilla, its mandibular corpus on the molar-loss side has a higher stress and displacement than the molar-presence side. Because the displacement and von Mises Stress was the highest on the lateral surface of mandibular corpus with molar loss, the stress level of the condyle on the molar-loss side is greater than that of the molar-presence side, which in turn caused the symphysis of the mandible to bend. In conclusion, the unilateral posterior bite collapse with molar loss under para-functional activities such as bruxism and clenching can affect the stress concentration on the condyle and mandibular corpus. It is therefore necessary to consider the biomechanical function of dento-skeleton under masticatory force while designing the occlusal scheme of restoration on alveolar bone with the posterior collapse.

• Communications of Mathematical Education
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• v.31 no.3
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• pp.331-347
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• 2017

The purpose of this study is to develop a sample chapter of mathematics textbook at the first middle school according to the model of supporting learners' self-directed learning. The self-directed learning is a learning strategy to develop learner's ability to solve unstructured problems by himself or herself. Basically, the textbook should included learning objectives distinctively. Second textbook should consist of some appropriate method for learners to learn content. Third, it suggests some plans to utilize learning strategies of this model effectively when authors or developers develop textbooks in future. Based on those condition, it is also requested that the sample chapter of the textbook be develop in order to study interestingly as well as to implement self-directed study, and content materials using mixed diverse subjects would be included in the chapter. Furthermore, the sample chapter which is suitable to the semester of managing self-directed learning middle school would be developed. For this purpose, in this study the 'Plane shapes' was selected dealt with in the first middle school. The sample chapter is developed at first by the researchers and then revised and completed through the checking from the professionalists two times.

• Journal of the Mineralogical Society of Korea
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• v.28 no.2
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• pp.127-133
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• 2015

Li-bearing muscovite is commonly found along with trioctahedral lepidolite in granitic pegmatites. Structurally, $Li^+$ ions can replace $K^+$ ions in the interlayer (Int) of muscovite or incorporate into vacancies of the dioctahedral sheet (Sub). However, detailed mechanism of the lithium incorporation into muscovite is challenging to investigate using experimental techniques alone. In the current study, density functional theory (DFT) has been applied to examine the crystal structure and energy variation when $Li^+$ resides in the interlayer or the octahedral sheet. Depending on the position of $Li^+$ (i.e., Int vs. Sub), DFT showed significant differences in the mica's structures such as lattice parameters, sheet thickness, interlayer separation, and OH angles with respect to the ab plane. DFT further showed that, in pure muscovite, $Li^+$ has a lower energy when it is located in Int than Sub. By contrast, in the case of $Fe^{2+}$ substitution into the octahedral sheet, $Li^+$ has a lower energy in Sub than in Int. These results imply that $Li^+$ incorporates into the Al octahedral sheets only when the octahedral sheets possess structural charges, suggesting cation substitution in the octahedral sheets plays an important role in the Li incorporation mechanism into muscovite. They can also explain the experimental observation about the positive relationship between $Fe^{2+}$ and $Li^+$ amounts in Li-bearing muscovite.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.5
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• pp.2298-2304
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• 2011

This paper describes and presents the design of a miniaturized low pass filter (LPF) for microwave frequency region using a common defected ground structure (CDGS). In this study a half-sized LPF is obtained using CDGS, while the previous LPFs with the conventional DGS showed a mild size-reduction. The common DGS (CDGS) is realized on the common ground plane of two microstrip lines, i. e double-sided microstrip lines, which exist back-to-back to each other. In order to show the validity of the proposed design, an example of LPF using CDGS and double-sided microstrip lines is designed, fabricated and measured using the dielectric substrate with the dielectric constant of 2.2 and with the thickness of 31mils. The size of the designed LPF using CDGS is only 52.6% compared to that of the previous LPF with the conventional DGS. In addition, it is shown that the performances of the proposed LPF are well preserved after the size-reduction with the measured S11 and S21 of -22dB, min and -0.19dB, max, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3176-3183
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• 2010

A multi-scale fatigue life prediction methodology of composite pressure vessels subjected to multi-axial loading has been proposed in this paper. The multi-scale approach starts from the constituents, fiber, matrix and interface, leading to predict behavior of ply, laminates and eventually the composite structures. The multi-scale fatigue life prediction methodology is composed of two steps: macro stress analysis and micro mechanics of failure based on fatigue analysis. In the macro stress analysis, multi-axial fatigue loading acting at laminate is determined from finite element analysis of composite pressure vessel, and ply stresses are computed using a classical laminate theory. The micro stresses are calculated in each constituent from ply stresses using a micromechanical model. Three methods are employed in predicting fatigue life of each constituent, i.e. a maximum stress method for fiber, an equivalent stress method for multi-axially loaded matrix, and a critical plane method for the interface. A modified Goodman diagram is used to take into account the generic mean stresses. Damages from each loading cycle are accumulated using Miner's rule. Monte Carlo simulation has been performed to predict the overall fatigue life of a composite pressure vessel considering statistical distribution of material properties of each constituent, fiber volume fraction and manufacturing winding angle.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.1
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• pp.36-41
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• 2018

This paper presents an implementation of a millimeter-wave(W band) multiflare-angle horn antenna. The proposed antenna is a multimode dual-polarized square horn having equal E- and H-plane beamwidths and consists of a multimode generating section, a four-square-waveguide exciter, orthomode transducers, and power combiners for the sum pattern formation. The antenna structure has been designed to allow for easy fabrication and the designed antenna has been fabricated to a precision of ${\pm}0.02mm$ by layer-by-layer machining and diffusion bonding. The input reflection coefficient and the radiation pattern of the fabricated antenna have been measured using a network analyzer and a far-field test facility. Measurements show that the proposed antenna has 17.7~18.3 dBi gain, $25.2{\sim}28.5^{\circ}$ beamwidth, and an input VSWR between 1.02~1.75, within ${\pm}0.5GHz$ from the center frequency.