• Journal of the Korean Academy of Clinical Electrophysiology
• /
• v.9 no.2
• /
• pp.39-46
• /
• 2011

Purpose : The purpose of this study was to compare the effect of three types of therapeutic exercises by applying them to lower back pain patients. Methods : This program was conducted for 30 patients 30 to 55 years old, who visited a rehabilitation center due to lower back pain. We separated participants into three groups with different therapeutic exercises: one with lumbar stabilization exercises, another with stretching exercises, and the other with both exercises. Each exercise was held once a day, 3 days a week, for 6 weeks. We analyzed the effect of these exercises by checking the change of lumbar muscle strength and pain relief. Lumbar muscle strength was measured by AS-Med and pain strength was estimated by VAS. Results : The result of the programs was established according to the following list: 1) Lumbar stabilization exercises and stretching exercises lead to higher lumbar muscle strength and pain relief (p<0.05). 2) Lumbar muscle strength in the lumbar stabilization exercise group was significantly higher than the stretching exercise group (p<0.05). 3) Pain relief in the stretching exercise group was significantly higher than the lumbar stabilization exercise group (p<0.05). Conclusion : This study shows all of the groups experienced higher lumbar muscle strength and pain relief. Specifically, there was higher lumbar muscle strength in the lumbar stabilization exercise group and higher pain relief in the stretching exercise group. Therefore the ideal intervention to improve lumbar muscle strength and pain relief for patients is to implement both lumbar stabilization exercises and stretching exercises.

• Earthquakes and Structures
• /
• v.12 no.2
• /
• pp.201-211
• /
• 2017

This paper experimentally investigates the effect of yield strength of reinforcing bars and stirrups on the seismic performance of reinforced concrete (RC) circular piers. Reversed cyclic loading tests of nine-large scale specimens with longitudinal and transverse reinforcement of different yield strengths (varying between HRB335, HRB500E and HRB600 rebars) were conducted. The test parameters include the yield strength and amount of longitudinal and transverse reinforcement. The results indicate that the adoption of high-strength steel (HSS) reinforcement HRB500E and HRB600 (to replace HRB335) as longitudinal bars without reducing the steel area (i.e., equal volume replacement) is found to increase the moment resistance (as expected) and the total deformation capacity while reducing the residual displacement, ductility and energy dissipation capacity to some extent. Higher strength stirrups enhance the ductility and energy dissipation capacity of RC bridge piers. While the product of steel yield strength and reinforcement ratio ($f_y{\rho}_s$) is kept constant (i.e., equal strength replacement), the piers with higher yield strength longitudinal bars are found to achieve as good seismic performance as when lower strength bars are used. When higher yield strength transverse reinforcement is to be used to maintain equal strength, reducing bar diameter is found to be a better approach than increasing the tie spacing.

• Journal of Technologic Dentistry
• /
• v.39 no.3
• /
• pp.153-159
• /
• 2017

Purpose: In this study, a corresponding porcelain coating material was applied to dental Co-Cr metal among PFM. Methods: The bonding strength of the fired specimens was measured by a three-point flexural rigidity test. SEM/EDS was used to observe the surface component of specimens. Results: First, All groups were higher than the minimum bonding strength of 25 MPa specified in ISO 9693 for dental metal-ceramics specimens. Second, The bonding strength of control group(WO) is 44.64 MPa. Experimental group DM was 35.45 MPa and DP was 31.82 MPa(P<0.05). Tukey's HSD tests results have shown that the bonding strength in control group(WO) is higher than that of experimental group(DM, DP). Third, In the case of metal - porcelain bonding strength, the application of opaque porcelain and firing were higher than those of the group treated with degassing process. Conclusion: The bonding strength was higher when the powder opaque porcelain was applied than the paste opaque porcelain.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2004.05a
• /
• pp.112-115
• /
• 2004

Bond between reinforcing bar and surrounding concrete is supposed to transfer load safely in the process of design of reinforced concrete structures. Bond failure of reinforcing bar generally take place by splitting of the concrete cover as bond force between concrete and reinforcing bars exceeds the confinement of the concrete cover and reinforcement. However, the confinement force has a limitation. Thus, the only variable is the bearing angle corresponding to the change of bond force. Higher rib height bars possessing higher shearing resistance can maintain higher bearing angle and higher splitting resistance when bars are highly confined, and consequently higher bond strength, than lower rib higher bars. In this study, from the evaluate bond strength of high Relative Rib Area Bars Using beam-end test specimens are compared with the current provisions for development of reinforcement, and the improved design method of bond strength is proposed.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2009.11a
• /
• pp.107-110
• /
• 2009

After inquiring into physical characteristics of using fly ash and alkali solution, it was found that higher pH density is favorable to strength development at early age and the higher the age is, the higher the compressive strength gets. Also, it was found that when there is more addition of activator, the compressive strength is higher. I was shown that more than atmospheric curing, steam curing was favorable for development of compressive strength. When the temperature of curing temperature was higher, most of the compressive strengths were higher. Thus, based on this study, it was understood that environmental-friendly chemically combined concrete using fly ash and alkali solution can be utilized without using cement.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.23 no.7
• /
• pp.998-1006
• /
• 1999

This study has investigated the relation between the sewing speed and seam breaking strength applied perpendicular to the seam direction. Breaking strength efficiency breaking mode of seams were examined under various sewing conditions using three kinds of sewing threads and four kinds of fabrics. The results obtained are as follows : 1. According to the increase in sewing speed seam strength was remarkably decreased. Seam strength and its loss difference were shown variously as threads and fabrics were mixed. 2. In case of fabrics with higher strength seam strength showed higher. And the seam strength was determined by the loop strength. 3. In case of fabrics with lower strength seam strength and its difference for every sample showed lower. So the strength of fabrics dominated the seam strength than those of threads. 4. In the experiment using various fabrics and sewing threads there was a type of thread appropriate to each fabric. Fabrics and threads with have similar physical properties were shown proper seam efficiency. 5. The breaking mode was different for every sample seam that was tested.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.23 no.5
• /
• pp.827-831
• /
• 1994

Investigation on the extractability, Mg2+-, Ca2+ , EDTA-ATPase activity and solubility of actomyosin prepared from leg and breast muscle of silky fowol were as follows. The extractability of actomyosin in leg and breast muscle was 779mg/100g and 1, 318mg/100g respectively, breast muscle was higher than leg muscle . Mg2+-ATPase activity of actomyosin was high inionic strength 0.02-0.10 and Mg2+ATPase activity of low ionic strength was higher than high ionic strength not related to the part. Ca2+ ATPase activity was high in ionic strength 0.05-0.13, the activity of leg muscle was higher that breast muscle. And EDTA-ATPase activity showed low in low ionic strength and showed high in high ionic strength, and increased greatly depend ionic strength up to 0.4. The solubility of actomyosin was not different in leg and breast muscle , the solution started in KCI concentration of 0.3M and ended in DCI concentration of 0.4M.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1998.10c
• /
• pp.60-65
• /
• 1998

This experimental Study presents the strength properties of mortar Using the Blast-furnace Slag Sand. It gives following result. The 3-days and 7-days compression strength is increase as substitution rate is higher. As W/C ratio increase, the strength is decrease. The flexural strength is increase as substitution rate is higher specially. As flexural strength ratio for compression strength is each 16.7%, 21.1%, 25.4% on 3-days, 7-days, 28-days, long age flexural strength is higher than short age.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2001.11a
• /
• pp.239-244
• /
• 2001

Opens the construction market recently, the construction industry of Korea has faced up to the barrier of globalism, and has been enforced to follow the various global standards in many aspects. Accordingly, it is expected that the test method related to the cement and concrete will be changed to conform to the international standards in Korea. Therefore, in this study, the strength tests are executed for the cement mortars, made by KS and ISO standards respectively, and then obtains such results. 1) The flow of the cement mortar according to ISO is about 8% higher ,than that of KS. 2) The flexural strength of the cement mortar according to ISO is about 10~20% higher than that of KS, and the compressive strength is about 30% higher. 3) The compressive strength relation between the cement mortars of KS and ISO may be expressed in the first-order recurrence formula as follows: Y = 1.33X - 8 In which X is the compressive strength(kgf/$\textrm{cm}^2$) of the mortar according to KS and Y is the compressive strength(kgf/$\textrm{cm}^2$) of the mortar according to ISO.

• Transactions on Electrical and Electronic Materials
• /
• v.13 no.6
• /
• pp.301-304
• /
• 2012

Epoxy/microsilica (65 phr)/nanosilica (0~5 phr) composites (EMNC) were prepared in order to develop a high-voltage insulation material, where phr means parts per hundred relative to the epoxy oligomer. Tensile and flexural tests of the composites were carried out, and the AC electrical breakdown strength was measured, after which all the data were estimated by Weibull statistical analysis. As the nanosilica content increased, the tensile strength increased, and the highest value was 117.7 MPa in the EMNC system with 3 phr nanosilica, which was ca. 10% higher than that of the system without nanosilica. The value then decreased after 3 phr. The flexural strength and AC electrical breakdown strength showed the same tendencies as the tensile strength. The highest value of the flexural strength was 184.6 MPa in the EMNC system with 3 phr of nanosilica, which was ca. 15% higher than that of the system without nanosilica. The strongest value of the AC electrical breakdown strength was 79.0 kV/0.5 mm in the EMNC system with 3 phr of nanosilica, which was ca. 34% higher than that of the system without nanosilica.