• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.11a
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• pp.177-185
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• 2000

The characteristics of multi-leaf feil bearing are investigated. The Foil bearing is preloaded and has several leaf foils modeled by curved beams. An analysis of the air foil bearing was performed, considering effects of foil deflection and compressible lubrication equation simultaneously. A parametric study shows that the number of foils significantly affect the static characteristics of air foil bearings and describes what the minimum film thickness means. The results include pressure profile, load capacity, dimensionless torque and minimum film thickness in the foil bearing.

• Advances in nano research
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• v.7 no.3
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• pp.181-190
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• 2019

The thermal buckling temperature values of the graded carbon nanotube reinforced composite shell structure is explored using higher-order mid-plane kinematics and multiscale constituent modeling under two different thermal fields. The critical values of buckling temperature including the effect of in-plane thermal loading are computed numerically by minimizing the final energy expression through a linear isoparametric finite element technique. The governing equation of the multiscale nanocomposite is derived via the variational principle including the geometrical distortion through Green-Lagrange strain. Additionally, the model includes different grading patterns of nanotube through the panel thickness to improve the structural strength. The reliability and accuracy of the developed finite element model are varified by comparison and convergence studies. Finally, the applicability of present developed model was highlight by enlighten several numerical examples for various type shell geometries and design parameters.

• Wind and Structures
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• v.38 no.3
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• pp.193-202
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• 2024

Modern high-rise tower designs incorporating recessed balcony cavity spaces can be prone to high-frequency and narrow-band Rossiter aerodynamic excitations under glancing incident winds that can harmonize and compete with recessed balcony volume acoustic Helmholtz modes and facade elastic responses. Resulting resonant inertial wind loading to balcony facades responding to these excitations is additive to the peak design wind pressures currently allowed for in wind codes and can present as excessive facade vibrations and sub-audible throbbing in the serviceability range of wind speeds. This paper presents a methodology to determine Cavity Amplification Factors to account for façade resonant inertial wind loads resulting from balcony cavity aero-acoustic-elastic resonances by drawing upon field observations and the results of full-scale monitoring and model-scale wind tunnel tests. Recessed balcony cavities with single orifice type openings and located within curved façade tower geometries appear particularly prone. A Cavity Amplification Factor of 1.8 is calculated in one example representing almost a doubling of local façade design wind pressures. Balcony façade and tower design recommendations to mitigate wind induced aero-acoustic-elastic resonances are provided.

• Journal of the Korean Home Economics Association
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• v.37 no.7
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• pp.29-43
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• 1999

The purpose of this study was to develop disposable diapers for the elderly in need by experimenting with wearing disposable diapers and analyzing the properties of materials of these diapers. The diapers were of two different types: one was a panty type for the elderly who were bed ridden, and the other was a pad type for the elderly who had incontinence. The subjects for the wearing test of the panty type were forty who were bed ridden, and there were forty subjects for the wearing test of the pad type who had incontinence. The disposable diapers for these experiments were chosen from those already found in the market place. Four panty types and three pad types were selected. From these experiments for the disposable diapers, the first prototypes were developed, and the second prototypes were proposed by experimenting with the first prototypes. The first panty prototype was designed to improve absorbing power, and we added waist rubber bands to prevent evacuation from back leaking and a frontal tape to prevent waistline film from tearing. The first pad prototype was designed to improve absorbing power also, and we added side rubber bands to prevent the side leaking and an adhesive tape on the fore part of the bottom to prevent the diapers from moving, and made the outline of the back area curved and thin to help hide the diaper from detection thus making the wearer feel better. From these test cases and analyzing the properties of materials with the first prototypes, we gained some success, but several points on further improvements were proposed to refine the final prototypes. The second panty prototype we proposed was to make 1he length longer, especially in the crotch area to prevent excess leaking and to fit the body more snugly. Also, the second pad prototype was proposed to reduce the total thickness of the diaper, and to improve the feeling and appearance.

• Bulletin of the Korean Chemical Society
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• v.32 no.spc8
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• pp.2955-2959
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• 2011

Second-order rate constants for nucleophilic substitution reactions of 2,4-dinitrophenyl benzenesulfonate 1a with a series of alicyclic secondary amines in MeCN have been measured spectrophotometrically and compared with those reported previously for the corresponding reactions performed in aqueous medium to investigate the effect of medium on reactivity and reaction mechanism. The amines employed in this study are found to be more reactive in the aprotic solvent than in $H_2O$. The reactions of 1a in MeCN result in a linear Br${\o}$nsted-type plot with ${\beta}_{nuc}$ = 0.58, which contrasts to the curved Br${\o}$nsted-type plot reported previously for the corresponding reactions performed in the aqueous medium (i.e., ${\beta}_2$ = 0.86 and ${\beta}_1$ = 0.38). Accordingly, it has been concluded that the reaction mechanism changes from a stepwise mechanism to a concerted pathway upon changing the medium from $H_2O$ to MeCN. Reactions of Y-substituted phenyl benzenesulfonates 1a-c with piperidine in MeCN result in a linear Br${\o}$nsted-type plot with ${\beta}_{lg}$ = -1.31, indicating that expulsion of the leaving group is significantly more advanced than bond formation in the transition state. The trigonal bipyramidal intermediate ($TBPy^{\pm}$) proposed previously for the reactions in $H_2O$ would be highly unstable in MeCN due to strong repulsion between the negative charge in $TBPy^{\pm}$ and the negative dipole end of MeCN. Thus, destabilization of $TBPy^{\pm}$ in MeCN has been concluded to change the reaction mechanism from a stepwise mechanism to a concerted pathway.

• The Research Journal of the Costume Culture
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• v.5 no.4
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• pp.112-129
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• 1997

This research, focused on the curved of the lower body, designated abdomen and hip gradient, crotch depth and crotch width the factors for which are able to influence on the appearence and the function of Divided Skirt and analized the changes when that were applied to a real pattern, and so the purpose of this research is to show the basic documents needed to design a Divided Skirt pattern fitting with the wear purpose and usage. The following are the results of this research. 1. The abdomen and hip gradient turned out as the most influential factor on the appearance and the function of Divided Skirt. The pattern of which the abdomen and hip gradient was designated as vertical zero degree, showed an excellent appearance and in case of function, the pattern of which thw angle of the abdomen and hip gradient of human body type was applied to itself without a particular designation turned out excellent. 2. In case of crotch depth, the pattern which had crotch depth＋2㎝, had a better appearance but influced nothing on function. 3. The factor of crotch width didn\`t have any influence on the appearance and function of Divided Skirt. 4. Referring to the results of the above, the Divided Skirt pattern of which the appearance and the function turned excellent, had the angle of abdomen gradient 4 degrees, the angle abdomen gradient 4 degrees, the angle of hip gradient/2+2.5 degrees, crotch depth+2㎝ and crotch width following human body type. In case of Divied Skirt worn when going out, the pattern which had the angle of abdomen and hip gradient vertical zero degree, crotch depth+2㎝ and crotch width following human body type, turned out suitable. Also, the suitable pattern of Divided Skirt for working had the abdomen and hip gradient following human body type, crotch depth+2㎝ and covering girth diameter/2±1㎝.

• Fashion & Textile Research Journal
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• v.11 no.6
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• pp.925-933
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• 2009

This research was carried out by analyzing a form and composition in baseball cap targeting 97 marketing products, and we have typified it by frequency analysis. We have carried out comparing and wearing test between comparative pattern and the most preferred three products of sports brand, fashion brand A, and fashion brand B (flex fit). And also, in order to provide basic indices for developing new pattern, we have carried out analysis of variance. 1. As a result of analyzing a form in baseball cap, the most general pattern type for crown is central cutting with six pieces. In a cap, a basic type with no decoration was the most general. In the size adjustment and decoration, belt type and embroidery type (front or side embroidery of the crown) was the most common, respectively. 2. As a result of comparing and analyzing six-piece typed crown pattern, the comparative pattern was the same and symmetric in size and form of three patterns in front, side, and back. However, the patterns of marketing products of three brands were different in size and form of three patterns in front, side, and back. The patterns of sports brand were the largest in crown height and width, thus it was good at providing activity and motion. The patterns of fashion brand A were the shortest in the crown length and well-curved in front pattern, so it was well-matched with head shape. The patterns of fashion brand B were well-described back side of head since its convex and long patterns in the back head. 3. As a result of wearing test by five-point Likert scale among brand, pattern of fashion brand B outperformed the others since it was well-matched with head shape. In the cap, pattern of fashion brand A is the most preferred which was 7.5 cm of length and 18cm of width.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.4
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• pp.376-381
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• 2010

The structural strength tests are usually performed to evaluate the structural strength and to verify the structural design and analysis of the vehicle structures. In this paper, the development of a compressed loading type apparatus to load distributed force over the surface of vehicle structure subjected to external loads was described. This apparatus is for structural materials which are easily to fail because of concentrated stresses. This apparatus can apply loads to specimens without any damage on the test specimen's surfaces by using flexible membrane and can be applicable to several kinds of surface profile of structures. The structural strength tests for the flat structure and curved structure with this apparatus were successfully performed, and the test results showed that this type of loading apparatus can be adequate to verify the structural integrity of the fragile structures.

• Journal of the Korean Home Economics Association
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• v.20 no.3
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• pp.9-18
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• 1982

In this study, we attempted to make an original pattern of clothing for an abnormal type of figure, especially for the type of kyphosis. We measured the curvature of the spine of a woman with kyphosis with a Martin measuring instrument and a silhouetter in the following ways. First, we counted the rate of shrinkage of the standard lines drawn on the surface of the body according as the body moved. Secondly, placing the front and back darts, the front and back shoulder darts and the side darts according to“Munhwa”pattern, we made cubic cuttings of four moving postures as well as the standing one. Thirdly, we superposed the developed patterns of the standing and the moving postures, measuring the position change and the amount of the chaange of the darts, and compared them. The results are as follows: 1) In the developed pattern of a cubic cutting of the basic pattern and the standing posture, the neckhole became larger than that of the basic pattern, and the waist line was lowered than that of the basic pattern because the center back line was shortened due to the curved backbone. 2) As for the change of the standard line according to the movement, we found that the waist line, the center front line, the center back line, the bust width line, the upper back width line and the back width line became longer. Special consideration must be given to the function of the clothing for an abnormal type of figure. 3) The difference of the measurements between the cubic cutting and the body measurement regardless of the body movement is due to a gap by an acute angle at the jutted place between the developed pattern and the body surface. We found that the body measurement of the upper back width line, the back width line and the bust line became larger. Consequently, in making an original clothing pattern, it is desirable that we must not place the front and the back waist darts at the jutted place on the back from the functional and the aesthetic viewpoint of clothing. It is also desirable that we must widen the neckhole because the shoulder angle is close to a straight line due to a jut of the upper back width line.

• Bulletin of the Korean Chemical Society
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• v.29 no.7
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• pp.1359-1363
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• 2008

Second-order rate constants have been determined spectrophotometrically for reactions of 2,4-dinitrophenyl 2- thiophenecarboxylate (2) with a series of alicyclic secondary amines in 80 mol % $H_2O$/20 mol % DMSO at 25.0 ${\pm}$ 0.1 ${^{\circ}C}$. The Brønsted-type plot exhibits a downward curvature, i.e., the slope decreases from 0.74 to 0.34 as the amine basicity increases. The $pK_a$ at the center of the Brønsted curvature, defined as $pK_a^o$, has been determined to be 9.1. Comparison of the Brønsted-type plot for the reactions of 2 with that for the corresponding reactions of 2,4-dinitrophenyl 2-furoate (1) suggests that reactions of 1 and 2 proceed through a common mechanism, although 2 is less reactive than 1. The curved Brønsted-type plot has been interpreted as a change in RDS of a stepwise mechanism. The replacement of the O atom in the furoyl ring by an S atom (1 $\rightarrow$ 2) does not alter the reaction mechanism but causes a decrease in reactivity. Dissection of the apparent second-order rate constants into the microscopic rate constants has revealed that the $k_2/k_{-1}$ ratio is not influenced upon changing the nonleaving group from furoyl to thiophenecarbonyl. However, $k_1$ has been calculated to be smaller for the reactions of 2 than for the corresponding reactions of 1, indicating that the C=O bond in the thiophenecarboxylate 2 is less electrophilic than that in the furoate 1. The smaller k1 for the reactions of 2 is fully responsible for the fact that 2 is less reactive than 1.