• Journal of Mechanical Science and Technology
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• v.17 no.7
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• pp.1044-1053
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• 2003

There are two major differences between the centerless infeed grinding process and the centerless through-feed grinding process. One is an axial movement of workpieces, and the other is that several workpieces are ground simultaneously and continuously by through-feeding. Because of these differences, through-feed ground parts inherently possess not only the roundness error but also the tapering error. The aims of the research reported in this paper are to examine this inherent tapering characteristic and to find the effects of grinding variables (center height angle, regulating wheel tilt angle, and shape of grinding wheel surface). To accomplish the objectives, experiments were carried out using two types of cylindrical workpiece shapes. Also, computer simulations were performed using the 3-D through-feed grinding model.

• Korean Journal of Plant Resources
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• v.11 no.3
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• pp.326-334
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• 1998

Vascular cambium in 16 species of Salicaceae is nonstoried in all of them and is made up of fusiform and ray initials. The growth of cambial girth occurred by pseudotransverse division of fusiform initials and subsequent apical intrusive growth of daughter initials. The measurements of fusiform initials in tangerntial sections have revealed that the average length varies from 252.2-437.1${\mu}{\textrm}{m}$ in investigated species, with the maximum being in Populus euramericana and the minimum in Salix purprea var. Multinervis. The length of fusiform initials depends on the length of the tapering end wall , therefore, the longer the length of the tapering end wall, therefore, the longer the length of the taperding end wall, the longer the length of fusiform initials. Ray initials have their own size, magnitude, and frequency of occrrence in each species. The relative proportion of ray initials fall about 15.0-24.5% in Salicaceae. Shrubby species of Salix have a lower ratio of ray initials than the species which possess wider trunks. New ray initials are originated from cut off the side or the end of fusiform initials and central partition of a fusiform initials.

• The Journal of Korean Academy of Prosthodontics
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• v.22 no.1
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• pp.109-122
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• 1984

The purpose of this study was to analyze the magnitude and mode of the stress distribution induced in the supporting alveolar bone and periodontal ligament and, to determine the displacement of abutment teeth and telescope denture base by applying chewing force to the telescope denture quantitatively and qualitatively. Two finite element models of telescope denture that were restored the missing mandibular second molar with two abutment teeth which were constructed. In two different models, parallel and tapering type telescope crowns were constructed. These finite element models of two cases used for these experiment were a two-dimensional mesiodistal section of the mandibular second bicuspid and first molar. Chewing force of 25Kg that was devided in the ratio of 45/155 (29%) in bicuspid and 55/155 (35.5%) in molars was applied to telescope denture and abutment teeth respectively. The displacement of the telescope denture base and abutment teeth and the stress distribution in the periodontal ligament and alveolar bone were analized to investigate the influence of chewing force acting on the telescope denture and abutment teeth. The results were as follows: 1. Abutment teeth displaced mesially and the magnitude of displacement of abutment teeth in vertical direction were more than that of horizontal direction in two cases. The displacement of abutment teeth on the telescope denture treated with tapering type telescope crown were less than that of the parallel type crown. 2. The displacement of the telescope denture base that were treated with parallel type telescope crown were less than that of treated with tapering type telescope crown. 3. The stress induced in the alveolar bone and periodontal ligament on abutment teeth that treated with parallel type telescope crown were more than that of treated with tapering type telescope crown and more stress induced in the alveolar bone than in the periodontal ligament. 4. In the telescope denture, the magnitude of displacement of abutment teeth and stress induced in the periodontal ligament and alveolar bone were within physiologic limit.

• Structural Engineering and Mechanics
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• v.67 no.4
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• pp.347-358
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• 2018

The main aim of this research was to investigate the shear strength of non-prismatic steel fiber reinforced concrete beams under monotonic loading considering different parameters. Experimental program included tests on fifteen non-prismatic reinforced concrete beams divided into three groups. For the first and the second groups, different parameters were taken into consideration which are: steel fibers content, shear span to minimum depth ratio ($a/d_{min}$) and tapering angle (${\alpha}$). The third group was designed mainly to optimize the geometry of the non-prismatic concrete beams with the same concrete volume while the steel fiber ratio and the shear span were left constant in this group. The presence of steel fibers in concrete led to an increase in the load-carrying capacity in a range of 10.25%-103%. Also, the energy absorption capacity was increased due to the addition of steel fibers in a range of 18.17%-993.18% and the failure mode was changed from brittle to ductile. Tapering angle had a clear effect on the shear strength of test specimens. The increase in tapering angle from ($7^{\circ}$) to ($12^{\circ}$) caused an increase in the ultimate shear capacity for the test specimens. The maximum increase in ultimate load was 45.49%. The addition of steel fibers had a significant impact on the post-cracking behavior of the test specimens. Empirical equation for shear strength prediction at cracking limit state was proposed. The predicted cracking shear strength was in good agreement with the experimental findings.

• Journal of electromagnetic engineering and science
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• v.5 no.1
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• pp.43-47
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• 2005

Microwave or optical photonic band-gap(PBG) structures are conventionally realized by cascading distributive elements in a periodic pattern. However, the frequency bandwidth obtained through such plainly periodic arrangement is typically narrow, corporate with a relatively high rejection side-lobe band. To alleviate such problems, a design involving a chirping and tapering technique is hence introduced and employed. The design has been applied in both a planar stratified dielectric medium as well as a strip-line transmission line structure, and results are validated when compared with the corresponding conventional PBG structure.

• Steel and Composite Structures
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• v.19 no.4
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• pp.897-916
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• 2015

A procedure for critical buckling moment of a tapered beam is proposed with the application of potential energy calculations using Ritz method. Respective solution allows to obtain critical moments initiating lateral buckling of the simply supported, modestly tapered steel I-beams. In particular, lateral-torsional buckling of beams with simultaneously tapered flanges and the web are considered. Detailed, numerical, parametric analyses are carried out. Typical engineering, uniformly distributed design loads are considered for three cases of the load, applied to the top flange, shear centre, as well as to the bottom flange. In addition simply supported beam under gradient moments is investigated. The parametric analysis of simultaneously tapered beam flanges and the web, demonstrates that tapering of flanges influences much more the critical moments than tapering of the web.

• Journal of the Optical Society of Korea
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• v.14 no.4
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• pp.337-341
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• 2010

A high sensitivity fiber optic temperature sensor based on a side-polished fiber (SPF) coupled to a tapered multimode overlay waveguide (MMOW) is proposed and studied. Both tapered and non-tapered MMOW were considered to study the effect of tapering of MMOW on the characteristics of the device and to investigate the criticality of the uniformity of the multimode overlay waveguide over the SPF. Present study shows that tapering of the MMOW can be used to tune the desired wavelength range without any loss in the sensitivity. Sensitivity up to 9 nm/$^{\circ}C$ within the temperature range of 25 to $100^{\circ}C$ can be achieved with the proposed sensor, almost 6 times higher compared even to state-of-the-art high-sensitivity grating-based fiber optic temperature sensors.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.524-527
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• 2003

In this paper, a new design for a Coplanar Waveguide (CPW) fed wide-band slot antenna is presented. To enhance the impedance bandwidth of the slot antenna, we proposed the tapering slot structure. A various resonance modes are generated in the tapering slot. The impedance bandwidth of the proposed antenna is about 12:1 ($2.0GHz{\sim}24.3GHz$) with $VSWR{\le}2$. Simulation results for return loss and radiation pattern are presented.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.2
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• pp.212-216
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• 2004

In this paper, a new design for a Coplanar Waveguide(CPW) fed wide-band slot antenna is presented. To enhance the impedance bandwidth of the slot antenna, we proposed the tapering slot structure. A various resonance modes are generated in the tapering slot. The measured impedance bandwidth of the proposed antenna is about 13:1(2.0 GHz∼25.9 GHz) with VSWR$\leq$2. Simulation and measurement results for return loss and radiation pattern are presented.

• Wind and Structures
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• v.21 no.5
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• pp.505-521
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• 2015

A general approach of aerodynamic optimization of tall buildings is presented in this paper, focusing on how to best compromise wind issues with other design aspects in the most efficient manner. The given approach is reinforced by establishing an empirical method that can quickly assess the across-wind loads and accelerations as a function of building frequencies, building dimensions, aspect ratios, depth-to-width ratios, and site exposures. Effects of corner modifications, including chamfered corner and recessed corner, can also be assessed in early design stages. Further, to assess the effectiveness of optimization by tapering, stepping or twisting building elevations, the authors introduce a method that takes use of sectional aerodynamic data derived from a simple wind tunnel pressure testing to estimate reductions on overall wind loads and accelerations for various optimization options, including tapering, stepping, twisting and/or their combinations. The advantage of the method is to considerably reduce the amount of wind tunnel testing efforts and speed up the process in finding the optimized building configurations.