• The Journal of Korean Physical Therapy
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• v.28 no.5
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• pp.269-273
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• 2016

Purpose: This study was conducted to examine the effect of kinesio taping (KT) on vertical jumping performance. Methods: Young women (n=24) performed vertical jumping under three conditions: kinesio taping, placebo taping, and no taping. All tapes were applied to both quadriceps and the gastrocnemius of the subjects. Vertical jump height and power were measured using an OptoGait, and the non-parametric Friedman test was used to identify differences between conditions. Results: No significant differences in maximum jump height or peak jump power between were observed between taping conditions. Conclusion: The results showed that KT did not facilitate muscle performance by generating higher jumping power or yielding a better jumping performance. As the functional performance is related to muscle strength, this finding may be explained by the fact that KT has no effects on muscle strength.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.293-296
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• 2001

This paper presents the results of field application test on the manufacturing of high fluidity concrete by applying flowing methods with segregation reducing type superplasticizer. Base concrete is made with 20% of fly ash, which is flowed during the transportation. According to test results, fluidity, placeability and segregation reducing performance meet the range of high fluidity concrete after flowing, while air loss occurs due to fly ash. There are no noticeable differences in compressive strengths between non-compacting and compacting methods. According to non-destructive tests with rebound and core strength test, we cannot detect any differences in strength according to the height in the structures.

• Journal of Mechanical Science and Technology
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• v.15 no.7
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• pp.1022-1031
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• 2001

The elastic modulus and fatigue properties of canine and human trabecular bone tissues (single trabecular) were experimentally determined on a microstructural level using four-point bending cyclic test, and they were compared based on microstructural characteristics and mineral density. The results showed that canine trabecular bone tissue had significantly lower modulus and lower fatigue strength than human tissue. The observed microstructural differences between the two tissues may be more responsible for the differences, although the lower mineral density in canine tissue might also have contributed to the lower modulus and fatigue strength.

• Journal of the Korean Society of Safety
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• v.31 no.1
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• pp.81-86
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• 2016

The WMSDs are known to occur more in upper extremity than lower extremity, and such a ratio is increasing each year. The motions or repeated work requiring excessive strength beyond worker's maximum grip strength were known as a major cause of the WMSDs in upper extremity. To prevent the WMSDs in upper extremity, research on the grip strength characteristics analysis of field workers that can be used as basic data for work design and manual tool design is needed. The purpose of this study is to identify various variables affecting grip strength and is to find out the impacts of grip strength on WMSDs. This research measured the grip strength of 327 field workers at Heavy Industries, and also conducted a questionnaire survey on individual characteristics and job characteristics. As a result of analyzing grip strength, the grip strength was statistically significant (P<0.1) according to the body surface area (BSA) of the research subjects. The differences between percentile groups of grip strength were statistically significant (P<0.1) according to pain levels of hand/wrist/finger and arm/elbow. The comparison results between the average grip strength of Korean adult males and the average grip strength of the survey-targeted heavy industry workers show that the average grip strength of the heavy industry workers was higher by 9.75 kg. This study analyzed relationship between grip strength and the pain levels of hand/wrist/finger and arm/elbow, and compared the findings in this study with those of existing preceding studies. Also, this research comparatively analyzed the grip strength of Korean adult males and survey-targeted heavy industry workers. The findings of this study can be used as useful data for ergonomic work design and manual tool design to prevent WMSDs at industrial worksites, given that almost no data on the grip strength of workers in the industrial sites are found in Korea.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.3
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• pp.52-58
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• 2013

To evaluate the anisotropic characteristics of Korean traditional paper-Hanji, the physical and mechanical characteristics of hand-made hanji, and machine-made hanji were investigated in this research. The densities of copying paper and newsprint paper appeared to be two times higher than the densities of hand-made hanji using Ssangbal sheet forming and hanji made of paper mulberry fiber. The breaking length, and tear index of both Hanji using Owangbal sheet forming, and hand-made Hanji using Ssangbal sheet forming appeared to be different according to the directions in paper. The breaking lengths of Hanji using Owangbal sheet forming showed little differences according to the directions. Breaking length of Hanji using Ssangbal sheet were slightly higher than those of Hanji using Owangbla sheet forming. The breaking lengths of machine-made hanji, copying paper, and newsprint paper were two to four times higher than those of hand-made Hanji. The breaking length showed higher differences according to the direction than the tear index. The tensile strength according to the directions in paper showed significant differences (${\alpha}$=0.05) in all papers used in this research.

• Bulletin of the Korean Chemical Society
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• v.13 no.1
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• pp.75-79
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• 1992

Differences in chromatographic properties in RPLC of four brands of cyano bonded silica stationary phases are rationalized in terms of the type and relative strength of the solute-stationary phase interactions, which can be readily inferred from multiple linear regression analyses of retention data for a set of standard compounds on the stationary phases under study based on the linear solvation energy relationships (LSERs). Although four brands of cyano bonded columns studied (CPS-Hypersil, Ultrasphere cyano, Spherisorb-CN and ${\mu}$-Bondapak-CN) have similar bonding density and have been prepared from monofunctional cyanopropylsilane reagents, they possess quite different, relative hydrogen bonding (HB) donor and acceptor strengths. Comparison of the retention behavior on a cyano-bonded silica column with that on an ODS column shows that there are significant differences in the strength of HB interactions between the solute and the stationary phase on the two columns with different functionalities. Information on the differences in the interaction characteristics among brands of the cyano-bonded silica columns and between the ODS and cyano-bonded columns can be utilized to optimize the selectivity for a given separation on these columns.

• The korean journal of orthodontics
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• v.22 no.2 s.37
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• pp.449-474
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• 1992

The purpose of this study was to evaluate the in vitro shear bond strengths to enamel and the failure sites of three ceramic brackets and one metal bracket in combination with light cured orthodontic adhesive. The brackets were divided into four groups. Each ceramic bracket group had different bonding mechanisms with adhesive. Group A; metal bracket with foil-mesh base (control group) Group B; ceramic bracket with micromechanical retention Group C; ceramic bracket with chemical bonding Group D; ceramic bracket with mechanical retention and chemical bonding. Forty extracted human lower first premolars were prepared for bonding and 10 brackets for each group were bonded to prepared enamel surfaces with $Transbond^{\circledR}$ light cured ortho dontic adhesive. Twenty four hours after bonding, the Instron universal testing machine was used to test the shear bond strength of brackets to enamel. After debonding, brackets and enamel surfaces were examined under stereoscopic microscope to determine the failure sites, Statistical analysis of the data was carried out with ANOVA test and $Scheff\acute{e}$ test using SPSS PC+. The results were as follows. 1 . There were statistically significant differences in mean shear bond strengths of three ceramic bracket groups (p < 0.05). Shear bond strengths of group C and D were significantly higher than that of group B and shear bond strength of group C was significantly higher than that of group D. 2. Group C and D both had significantly higher shear bond strengths than metal bracket (group A), but there were no significant differences in shear bond strengths between group A and B (p < 0.05). 3. The failure sites of four bracket groups were also different. Group C and D failed primarily at enamel-adhesive interface, but group A and B failed primarily at bracket base-adhesive interface. 4. Among all ceramic bracket groups, group B was very similar to metal bracket in the aspect of shear bond strength and failure site.

• Restorative Dentistry and Endodontics
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• v.24 no.1
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• pp.233-239
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• 1999

Recently, a second generation composite resin system(ceromer) was introduced with significantly improved mechanical properties. The purpose of this study was to compare a ceromer with the other restorative materials and to assess its clinical usefulness. In this study, we used four restorative materials : amalgam (BESTALOY$^{(R)}$), indirect composite resin (Clearfil CR Inlay$^{(R)}$), ceromer (Targis$^{(R)}$) and ceramic (Vintage$^{(R)}$). And then we devided into four groups. The materials of each group were as follows : Amalgam group : BESTALOY$^{(R)}$ (Dong Myung Dental Industrial Co.) Composite Resin group : Clearfil CR Inlay$^{(R)}$ (Kuraray) Ceromer group : Targis$^{(R)}$ Dentin (Ivoclar-Vivadent) Ceramic group : Vintage$^{(R)}$ (Shofu Inc.) According to the above classification, we made samples through the polymerization of BESTALOY$^{(R)}$, Clearfil CR Inlay$^{(R)}$ and Targis$^{(R)}$ with separable cylindrical metal mold and firing of Vintage$^{(R)}$ in a investment mold. And then, we measured and compared the value of compressive strength, diametral tensile strength and Vicker's microhardness of each sample. The results were as follows : 1. Amalgam showed the highest value of compressive strength (390.37${\pm}$42.22MPa) and the value of ceromer was somewhere between ceramic and indirect composite resin. There were significant differences among the experimental groups(p<0.001). 2. Indirect composite resin showed the highest value of diametral tensile strength (74.21${\pm}$15.33MPa) and there was no significant difference with ceromer. Ceromer was higher diametral tensile strength than amalgam and ceramic (p<0.001). 3. Ceramic showed the highest value of microhardness (538.44${\pm}$37.38Hv) and the value of ceromer was somewhere between ceramic and indirect composite resin. There were significant differences among the experimental groups (p<0.001).

• The Journal of Korean Academy of Prosthodontics
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• v.30 no.2
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• pp.225-232
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• 1992

The purpose of this study was to compare the bond strength of the glass ionomer luting cements after the functional loads were applied to the crowns respectively 10 min, 30 min, 1 hr, 24 hrs later after mixing of cements. The conventional (GC Fuji I; GC Int. Co., Japan), water hardening type (Ketac Cem; ESPE, W. Germany) glass ionomer luting cement and C-dent ZPC (Confi-Dental Products Co., U.S.A.) as a control were used. The results of this study were obtained as follows: 1. In the bond strength of GC Fuji I, 24 hr-group was highest and there were no statistically significant differences among 10 min-, 30 min- and 1 hr- groups. 2. l3 the bond strength of Ketac Cem and C-dent ZPC, there was no statistically significant differences among 10 min-, 30 min-, 1 hr- and 24 hr-groups respectively. 3. Comparing the bond strength among cements in 10 min-, 30 min-groups respectively, GC Fuji I was lowest and there was no statistically significant difference between Ketac Cem and C-dent ZPC. 4. The bond strengths between GC Fuji I and Ketac Cem were not significantly different in 1 hr-, 24 hr-group. 5. The bond strengths among 3 types of cements were not significantly different in 24 hr-groups.

• Journal of the Korea Institute of Building Construction
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• v.4 no.2
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• pp.129-136
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• 2004

High fluidity concrete(HFC) requires high dosage of superplasticizer to acquire sufficient fluidity, and high contents of fine powder and viscosity enhancing admixtures to resist segregation. The use of high amount of admixtures to make HFC at batcher plant in ready mixed concrete company is one of the reasons to raise the manufacturing cost of HFC. For this reason, new type of manufacturing method of HFC are described using both flowing concrete method and segregation reducing superplasticizer(SRS) in order to gain economical profit and offer the convenience for quality control.. As dosage of melamine based superplasticizer increases, it shows that fluidity and bleeding increase, while air contents and ratio of segregation resistance decrease. It also shows that addition of viscosity agent into superplasticizer reduce bleeding and improve segregation resistance of concrete. Dosage of AE agent into superplasticizer containing viscosity agent recovers loss of air contents during flowing procedure. Combination of proper contents of superplasticizer, viscosity agent and AE agent make possible to develope segregation reducing type superplasticizer. Compressive strength of high fluidity concrete applying flowing method with it is higher than that of base concrete. No differences of compressive strength between compacting methods are found. For the estimation of construction cost of high fluidity concreting using segregation reducing type superplasicizer, under same strength levels, although material cost of high fluidity concrete is somewhat higher than that of plain concrete due to segregation reducing type superplasticizer cost, labor cost and equipment cost of high fluidity concrete is cheaper than that of plain concrete. However, based on the strength differences, high fluidity concrete shows lower material cost, labor cost and equipment cost than that of plain concrete due to decreasing in size of member and re-bar caused by high strength development of concrete.