• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.147-148
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• 2009

We have fabricated a down tapered polymer tip on optical fiber end-face by a guided UV light. One side of fiber was aligned with a mercury-xenon lamp and another was put into UV curable polymer. A shape of tip was controlled by adjusting an irradiance of lamp and time of exposure. A bending effect also affects the result. Optical characteristic was achieved preliminarily with solution of minute particles.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.18 no.2
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• pp.245-252
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• 1996

The purpose of this study was to develop the implant which has superior stress distribution and primary stability to others by using Instron test and finite element method. The model used in the experiment were cylinder type implant, tapered screw type implant, screw type implants. Recognizing that the number of samples were small and the lack of applying press-fit conditions to the cylinder type, we can make the following conclusions.

• Journal of Korean Vacuum Science & Technology
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• v.2 no.1
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• pp.1-8
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• 1998

The uniform distributed pumping model is used to derive analytic expressions of the pressure profile for the molecular flow regime in linearly tapered or flared(conical or pyramidal) tubes with wall sorption. The concept of transmission conductance for sticky tubes of arbitrary shape is newly introduced to calculate the transmission probability using the pressure profile. The transmission probability obtained analytically for a conical sticky tube is compared with that from the Monte Carlo simulation.

• Journal of Advanced Marine Engineering and Technology
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• v.9 no.4
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• pp.339-347
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• 1985

Precise measurement of flowrate is considered as an important measuring factor in mechanical and chemical experiment. Although there are many methods to measure flowrate, Float type flowmeter is widely used because of its easy attachment to piping and high measuring precision. To design the precise float type flowmeter, much design information such as tapered-tube dimensions, float size, float shape and float material is required. In this paper, fundamental design theory for float type flowmeter according to the given flowrate range is suggested and compensation coefficients of volumetric and weight flowrate for water, R-113 and air are calculated.

• Journal of the Korean Institute of Navigation
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• v.18 no.2
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• pp.151-158
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• 1994

A wide band design method of an electromagnetic wave absorber using exponentially tapered ferrite, which has very wide band frequency characteristics, is proposed and discussed. The wide band electroma-gnetic wave absorber can be designed by the proposed equivalent material constants method for the re-gions varying spatially in the shape of ferrite. Futhermore, the wide band ferrite electromagnetic wave absorber with taper, which have not only exce-llent reflectivity frequency characteristics but also the band width of 30MHz to 2150 or 2450MHz under the tolerance limits of -20dB reflectivity, were designed.

• International Journal of High-Rise Buildings
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• v.8 no.4
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• pp.235-253
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• 2019

This paper reviews shape optimization studies for tall and super-tall building design. Firstly, shape effects on aerodynamic and response characteristics are introduced and discussed. Effects of various configurations such as corner modifications, taper, setback, openings, and twists are examined. Comprehensive comparative studies on various configurations including polygon building models, and composite type building models such as corner-cut and taper, corner-cut and taper and helical, and so on, are also discussed under the conditions of the same height and volume. Aerodynamic characteristics are improved by increasing the twist angle of helical buildings and increasing the number of sides of polygon buildings, but a twist angle of $180^{\circ}$ and a number of sides of 5 (pentagon) seem to be enough. The majority of examined configurations show better aerodynamic characteristics than straight-square. In particular, composite type buildings and helical polygon buildings show significant improvement. Next, shape effects on pedestrian-level wind characteristics around tall and super-tall buildings are introduced and discussed. Corner modification buildings show significant reductions in speed-up areas. On the other hand, setback and tapered models with wider projected widths near the ground show adverse effects on pedestrian-level wind characteristics.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.4 no.1
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• pp.93-101
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• 1984

New formulas to determine the critical elastic buckling load of long tapered columns are given. This study is restricted to solid round or rectangular columns with fixed-free ends as often used in highway design. The exact solution of the differential equation of the deflection curve is expressed in terms of Bessel Function and the solution is numerically evaluated using Bisection method by computer. In the F.E.M analysis of columns under their own weight, the stability problem can be resulted in a eigen value problem of conservative system. Approximate solution by the F.E.M is evaluted numerically using Jacobi method and compared with exact solution of the prismatic column to increase the precision. In addition, critical buckling load of the tapered column for every shape factor and ratio of cross-sectional change (Diameter of bottom end/Diameter of upper end) was converted into a comparable expression to critical buckling load of the prismatic column.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.2
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• pp.207-216
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• 2006

Statement of Problem: To conduct a successful function of implant prosthesis in oral cavity for a long time, it is important that not only structure materials must have the biocompatibility, but also the prosthesis must be designed for the stress, which is occurred in occlusion, to scatter adequately within the limitation of alveolar bone around implant and bio-capacity of load support. Now implant which is used in clinical part has a very various shapes, recently the fixture that has tapered form of internal connection is often selected. However the stress analysis of fixtures still requires more studies. Purpose: The purpose of this study is to stress analysis of the implant prosthesis according to the different implant systems using finite element method. Material and methods: This study we make the finite element models that three type implant fixture ; $Br{\aa}nemark$, Camlog, Frialit-2 were placed in the area of mandibular first premolar and prosthesis fabricated, which we compared with stress distribution using the finite element analysis under two loading condition. Conclusion: The conclusions were as follows: 1. In all implant system, oblique loading of maximum Von mises stress of implant, alveolar bone and crown is higher than vertical loading of those. 2. Regardless of loading conditions and the type of system. cortical bone which contacts with implant fixture top area has high stress, and cancellous bone has a little stress. 3. Under the vertical loading, maximum Von mises stress of $Br{\aa}nemark$ system with external connection type and tapered form is lower than Camlog and Frialit-2 system with internal connection type and tapered form, but under oblique loading Camlog and Frialit-2 system is lower than $Br{\aa}nemark$ system.

• The Journal of Korean Academy of Prosthodontics
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• v.34 no.3
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• pp.457-463
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• 1996

An esthetically pleasing result in denture service is dependent upon several consideration. Esthetic considerations for the edentulous patient include tooth size, shape, arrangement, positioning, gingival contour, age, sex, personality differences, and ethnic type. Especially, the form of anterior artificial teeth is an important factor on the esthetics. The selection of artificaial teeth requires understanding and knowledge on physical and biologic factors and has to meet the indivisul esthetics and functional needs of each patient. However, the selection of artificial teeth is based on the large degree of subjective judgement of the dentist, Therefore, this is one of the most unscientific processes. Many attempts have been made to find a guideline for the selection of artificial teeth. Temperamental theory by White and Hall utillized with the physical characteristics such as body size, body form, color of eyes and hair, and disposition. SPA theory by Frush and Fisher utilized with the basis of sex, personalities, and age of the indivisual. There has not been provided for a guideline and study on the selection of artificial teeth for Koreans yet. This study was aimed to evaluate the William's typal matching theory in Koreans. 1. The facial forms of korean adult were ovoid(46.3%), square(36.7%) and tapered(17.0%) form. 2. The anatomic forms of natural maxillary incisors were ovoid(45.3%), tapered(31.3%), square(23.3%) form. 3. The forms of face and natural maxillary incisors were ovoid(21.9%), squared(11%), tapered(6.3%). 4. The natural maxillary incisors were similar in form to the facial form only in 39%. There was no correlation between the form of the face and the form of natural maxillary central inisors in Koreans. 5. Artificaial teeth which was selected according to the typal matching theory did not represent the form of the natural teeth in 61 per cents of the fatal, but it felt that they harmonized with the form of the patient's face and produced good results.

• Journal of Powder Materials
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• v.15 no.1
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• pp.46-52
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• 2008

The restrictor, which is a fluid channel from a reservoir to a chamber inside a thermal micro actuator, has been fabricated using ArF and KrF excimer lasers, Diode-Pumped Solid State Lasers (DPSSL) and femtosecond lasers for a feasibility study. A numerical model of fluid dynamics for the actuator chamber and restrictor is presented. The model includes bubble formation and growth, droplet ejection through nozzle, and dynamics of fluid refill through the restrictor from a reservoir. Since an optimized and well-fabricated restrictor is important for a high frequency actuator, some special beam delivery setups and post processing techniques have been researched and developed. The effects of variations of the restrictor length, diameter, and tapered shapes are simulated and the results are analyzed to determine the optimal design. The numerical results of droplet velocity and volume are compared with the experimental results of a cylindrical-shaped actuator. It is found that the micro actuators having tapered restrictors show better high frequency characteristics than those having a cylindrical shape without any notable decrease of droplet volume. The laser-fabricated restrictors demonstrate initial feasibility for the laser direct ablation technique although more development is required.