• The Journal of Korean Academy of Prosthodontics
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• v.49 no.4
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• pp.316-323
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• 2011

Purpose: The purpose of this study was to investigate the effect of different thread designs on the marginal bone stresses around dental implant. Materials and methods: Standard ITI implant(ITI Dental Implant System; Straumann AG, Waldenburg, Switzerland), 4.1 mm in diameter and 10 mm in length, was selected as control. Test implants of four different thread patterns were created based on control implant, i.e. maintaining all geometrical design of control implant except thread pattern. Four thread designs used in test implants include (1) small V-shape screw (model A), (2) large V-shape screw (model B), (3) buttress screw (model C), and (4) trapezoid screw (model D). Surface area for unit length of implant was 14.4 $mm^2$ (control), 21.7 (small V-shape screw), 20.6 (large V-shape screw), 17.0 (buttress screw) and 28.7 $mm^2$ (trapezoid screw). Finite element models of implant/bone complex were created using an axisymmetric scheme with the use of NISA II/DISPLAY III (Engineering Mechanics Research Corporation, Troy, MI, USA). A load of 100 N applied to the central node on the crown top either in parallel direction or at 30 degree to the implant axis (in order to apply non-axial load to the implant NKTP type 34 element was employed). Quantification and comparison of the peak stress in the marginal bone of each implant model was made using a series of regression analyses based on the stress data calculated at the 5 reference points which were set at 0.2, 0.4, 0.6, 0.8 and 1.0 mm from implant wall on the marginal bone surface. Results: Results showed that although severe stress concentration on the marginal bone cannot be avoided a substantial reduction in the peak stress is achievable using different thread design. The peak marginal bone stresses under vertical loading condition were 7.84, 6.45, 5.96, 6.85, 5.39 MPa for control and model A, B, C and D, respectively. And 29.18, 26.45, 25.12, 27.37, 23.58 MPa when subject to inclined loading. Conclusion: It was concluded that the thread design is an important influential factor to the marginal bone stresses.

• Korean journal of food and cookery science
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• v.7 no.3
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• pp.7-12
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• 1991

Castera is a favorite food which is well known to the general public made by egg, sugar and wheat flour. This study is carried out in order to investigate to the physical properties of eastern. The results are summarized as follows: 1) As a result of the sensory evaluation for eastern with 19 kinds of material in Kyushu on the market, it could be classified into 3 types: A) high grade (Castera), C) low grade (Sponge cake), and B) midium grade (Something middle of those). 2) In the texturometer measurement for eastern, hardness of A type was highest, B and C are 22∼35% lower than A type, while cohesiveness and springiness are not significantly different. 3) In the creep test, 3 types are all the S-element Voigt model, consisting of Hookean body, Newtonian body and two sets of Voigt body. Eo of A type is 13∼36% higher than other types, it tends to the same result of hardness. The parts of retardation strain of A type are 21∼41% lower than B type, 8∼l3% higher than C type, respectively. 4) About the day change of eastern of A type, mechanical model is not changed.

• Magazine of the Korea Concrete Institute
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• v.7 no.2
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• pp.117-125
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• 1995

In this study, the damage to a concrete br~dge pier due to flre caused by the fall of an oil truck were investigated by the use of FEM and by tensile tests for reinfortements. And thtse results were analyzed and compared with the measured values. In the FEM calculations, the selected variable was the fire temperature $T_a=500-800^{\circ}C$. The fixed values were the heat transition coefficient ${\alpha}=2000W/m^2{\cdot}K$. the initial temperature of concrete $T_0=5{\circ}C$ and the fire duration t=30 minutes. As the results obtained from numerical calculations, the property darrlage zone ap,)eared to be 1.5-4.1cm and the structure damage zone appeared to be 8.7- 10.1cm from the concrete surface. And this results give values very similar to those measured, nanlelv 2-4cm and 8~10cm respectively. The results frorn tensile tests give no serious loss of the tensile strength.

• Journal of Sensor Science and Technology
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• v.7 no.5
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• pp.356-363
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• 1998

Using the results analyzed by FEM(Finite Element Method). the microheaters with the stress-balanced $Si_3N_4$(150 nm)/$SiO_2$(300 nm)/$Si_3N_4$(150 nm) diaphragms were fabricated by silicon micromachining techniques. Pt was used as microheater materials. Pt temperature sensor was fabricated to measure the temperature of microheaters. Resistance of temperature sensor and power dissipation of microheater were measured and calculated at the various temperatures. The thermal distribution of heater was examined by a IR thermoviewer. Measured and simulated results are compared and analyzed. The temperature coefficient of resistance of heater was about $0.00379/^{\circ}C$. Pt heater showed the power dissipation of about 51 mW at $300^{\circ}C$ and a uniform thermal distribution on the surface.

• Korean Journal of Soil Science and Fertilizer
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• v.15 no.2
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• pp.117-127
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• 1982

Mulberry plants (Morus alba L.) were grown in pots with the following different nitrogen sources: ammonium sulphate, urea, ammonium nitrate, sodium nitrate + ammonium nitrate ($NO_3:NH_4$=2:1), and sodium nitrate. The effects of the nitrogen sources on mulberry yields, nitrogen recovery, distribution of ions and cation-anion balance (C-A) along leaf sequence and growth stage were investigated. The results were as follows: 1. Leaf yields and nitrogen recovery decreased with increasing $NO_3$-N application rates. 2. Relative cation contents in leaves in the early growth stages showed the following pattern : Na < Mg < Ca < K. However, the order of Ca and K reversed in the later stages. The order of anion contents chifted from $SO_4$ < $NO_3$ < Cl < $H_2PO_4$ in the early stages to $NO_3$ < Cl < $SO_4$ < $H_2PO_4$ in the later stages. 3. Contents of K, $H_2PO_4$, $SO_4$, $NO_3$, T-N and the sum of anion contents (${\sum}A$) were higher in upper leaves whereas Ca, Mg, Cl, the sum of cation contents (${\sum}C$) and (C-A) were higher in lower leaves. 4. When $NO_3$ in leaves decreased, Cl and K as counter-cations increased and consequently Ca decreased. 5. The (C-A) in leaves varied with leaf sequence and growth stage from 700 to 900 me/kg D.M.

• Journal of Korean Society of Steel Construction
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• v.28 no.4
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• pp.243-251
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• 2016

Longitudinally structural cracks are sometimes observed in the pavement on steel plate deck bridges because traffic truck loadings can cause large local deformations of the thin deck plate stiffened by longitudinal and transverse beams. In this study, an improved finite strip method using flat-shell strip, prism, and link elements is presented to investigate local deformations of steel decks with pavements in which flexural and torsional stiffness effects of thin floor beams are rigorously taken into account. A simplified deck model extracted from steel plate-girder bridges is analyzed using the developed FSM and the commercial FE program, ABAQUS and also, their numerical results are compared and discussed.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.13 no.2
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• pp.172-179
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• 2010

Purpose: Visceral adipose tissue may be strongly linked to increased metabolic risks in adults. However, because little is known regarding the effect of visceral adipose tissue in children and adolescents, we performed this study to determine the association between abdominal fat distribution and metabolic risk factors in this population. Methods: One hundred one children and adolescents (78 males and 23 females; mean age, 10.8${\pm}$2.4 years) were enrolled. The anthropometric data and metabolic risk factors were evaluated. Theabdominal fat distribution was assessed according to the CT measurement. Age-adjusted, partial correlations were performed among the visceral adipose fat area (VFA), subcutaneous adiposefat area (SFA), metabolic risk factors, and anthropometrics. Results: The SFA increased more rapidly than the VFA with advancing years in both genders. In males, the VFA and SFA were positively correlated with anthropometrics. The VFA was correlated with low HDL-cholesterol and the SFA was correlated with diastolic blood pressure (DBP). However, there was no statistical significance between the VFA, SFA, anthropometrics, and other metabolic risk factors. The VFA and SFA were strongly linked to a number of metabolic risk factors, such as other anthropometrics. Conclusion: This study investigated how a low HDL-C was correlated with VFA and how a high DBP was associated with SFA in Korean male children and adolescents. Our results suggest that the correlation between the VFA, SFA, and metabolic risk factors was relatively weak compared to that reported in previous adult studies.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.1
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• pp.89-96
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• 1995

The application of the 4-pole parameter method with 1 - D theory is acceptable for intake system analysis. However, the limitaion appears during the analysis of complicated intake system since this method is developed based on the plane wave thoery. For the intake system analysis, the usage of BEM(Boundary Element Method) is introduced describing its disadvantage. To combine benefits of both method. a hybrid method is introduced. This hybrid method consists of the 4-pole parameter with I-D theory and BEM. The developed method is applied to an automobile intake system analysis to obtain the transmission loss.

• Journal of computational fluids engineering
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• v.4 no.2
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• pp.39-46
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• 1999

The FVM(Finite Volume Method) have been used mainly for the flow analyses in the piston-cylinder. The objective of the present study is to analyze numerically the piston-driven intake flows using the FEM(Finite Element Method). The FEM algorithm used in this study is 4-step time-splitting method which requires much less execution time and computer storage than the velocity-pressure integrated method and the penalty method. And the explicit Lax-Wendroff scheme is applied to nonlinear convective term in the momentum equations to prevent checkerboard pressure oscillations. Also, the ALE(arbitrary Lagrangian Eulerian) method is adopted for the moving grids. The calculated results show good agreement in comparison with those by the FVM and the experimental results by the LDA.

• Journal of the Korea Convergence Society
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• v.2 no.4
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• pp.47-52
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• 2011

Periodontal disease is a common inflammatory disorder that is being considered as a risk factor for atherosclerotic complication. Recent epidemiological evidence also supports that its potential association with increased blood pressure levels and hypertensive prevalence. Data from cross-sectional studies suggest that in hypertensive patients periodontal disease may enhance the risk and degree of target organ damage. So dental infections have been associated with cardiovascular diseases. There are potential pathophysiologic links between hypertension and periodontits. The role of the inflammatory pathway include C-reactive protein(CRP). CRP is an inflammatory mediator that has been shown to predict the development of hypertension independently of baseline BP and traditional risk factors, has been consistently reported as at least mildly elevated in patients with periodontal disease. Reactive oxygen species produced by locally infiltrating neutrophils participate in periodontal tissue destruction. Periodontits can lead to inflammatory responses in the atrial myocardium, which disturbs the structural and electrophysiologic properties of the atrium and facilitates atrial fibrillation in the animal experiment.