• Restorative Dentistry and Endodontics
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• v.17 no.2
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• pp.331-341
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• 1992

The purpose of this study was to measure the polymerization contraction stress of two types of composite resins; chemical cured type(Cliarfil F II, Kuraray, Japan) and photo-cured type(Photo-Clearfil Bright, Kuraray, Japan). The stresses of composite resin by contraction measured with specially designed measuring device(Fig. 1). The stresses caused by shrinkage during hardening of specimens were measured according to the type of composite resins, thickness of specimen(0.65, 1.30 and 1.95mm), and ratio of catalyst to base in case of only chemical cured composite resin(0.5, 1.0 and 1.5). As the composite resin specimen shrank on hardening, the load cell recorded force vs time automatically on pen-recorder(Toa, Japan) with a cross-head speed 60mm/hr at 0~10 voltages up to 2 hours. The experiments were conducted in a room maintained at $23{\pm}2^{\circ}C$ and relative humidity $50{\pm}10%$. The results were as follows. 1. The contraction stress during hardening was higher in photo cured composite resin than in chemical cured composite resin. 2. The contraction stress during hardening was increased with thickness of composite resin specimen. 3. In chemical cured composite resin, the polymerization contraction stress was decreased with ratio of catalyst and base. 4. The contraction stress during polymerization was higher in early time after insertion of photo cured composite resin and chemical cured composite resin.

• Women's Health Nursing
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• v.23 no.2
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• pp.109-116
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• 2017

Purpose: The purpose of this study was to test effects of music therapy on stress due to preterm labor and uterine contraction in pregnant women with preterm labor. Methods: An experimental research design was used. Participants were 35 pregnant women with preterm labor who were between 20 to 37 weeks of pregnancy: control group (n=18) received only tocolytic drugs, while experimental group (n=17) received additional music therapy. In the experimental group, Traumerei was applied before Non-Stress Test (NST) from the second day to fifth day after admission as music therapy. Results: There was a statistically significant difference in stress due to preterm labor (z=-3.368, p<.001) between the two groups. Conclusion: The music therapy is an effective method for reducing the stress of pregnant women with preterm labor.

• Geomechanics and Engineering
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• v.13 no.6
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• pp.907-928
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• 2017

The effects of seepage force and out-of-plane stress on cavity contracting and tunnel opening was investigated in this study. The generalized Hoek-Brown (H-B) failure criterion and non-associated flow rule were adopted. Because of the complex solution of pore pressure in an arbitrary direction, only the pore pressure through the radial direction was assumed in this paper. In order to investigate the effect of out-of-plane stress and seepage force on the cavity contraction and circular tunnel opening, three cases of the out-of-plane stress being the minor, intermediate, or major principal stress are assumed separately. A method of plane strain problem is adopted to obtain the stress and strain for cavity contracting and circular tunnel opening for three cases, respectively, that incorporated the effects of seepage force. The proposed solutions were validated by the published results and the correction is verified. Several cases were analyzed, and parameter studies were conducted to highlight the effects of seepage force, H-B constants, and out-of-plane stress on stress, displacement, and plastic radius with the numerical method. The proposed method may be used to address the complex problems of cavity contraction and tunnel opening in rock mass.

• Progress in Superconductivity and Cryogenics
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• v.2 no.2
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• pp.20-25
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• 2000

A CICC type superconducting bus-line electrically connecting a superconducting magnet to a power supply is cooled down to low temperature under the external magnetic field during operation. The thermal contraction during the cooling may be constrained by the supports which are installed to protect the bus-line from Lorenz magnetic forces. This constrained contraction causes thermal stresses in the bus-line to release thermal contraction. The minimum stress conditions in the bus-line may be optimized by controlling the supporting arrangement considering the thermal contraction and the external field. The analytical method to find optimal supports arrangement was suggested by using the beam theory, and numerical calculation using commercial code was performed to verify the suggested analytical optimization method.

• Korean Journal of Adult Nursing
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• v.12 no.2
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• pp.267-277
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• 2000

The purpose of this study was to help the women with stress urinary incontinence lead more comfortable life, by letting them to do pelvic muscle exercise and to learn by direct experience the effect that urinary incontinence is controlled. The research design was a one-group pretest-posttest design. The subjects were 16 middle-aged women(over 38) with stress urinary incontinence. The study was conducted from August 1, to October 11, 1999. Women trained themselves for muscular strength and endurance, every the other day for each exercise for six weeks at home(that means each exercise for more than three days a week) in the pelvic muscle exercise program which was developed by Dougherty et al., and filled out exercise participation card every week. They visited laboratory once a week to get visual feedback, by means of Perineometer, of how the pelvic muscle exercise was going on. Stress Urinary Incontinence Scale that Lee, Young-Sook revised and supplemented Hendrickson's original scale was used for measuring the frequency and situation scores of urinary incontinence, "30 minute pad test" was carried out for measuring the amount of urinary incontinence, and Perineometer was used for measuring maximum vaginal contraction pressure. Percentage, mean, standard deviation and Wilcoxon signed ranks test were used for data analysis by means of SPSS/PC+ WIN 9.0 program. The results were summarized as follows : The hypothesis 1 that after carrying out pelvic muscle exercise program on women with stress urinary incontinence, the weekly degree of urinary incontinence would reduce compared to before the exercise was supported. The hypothesis 1-1 that after carrying out pelvic muscle exercise program on women with stress urinary incontinence, the weekly frequency of urinary incontinence would reduce compared to before the exercise was supported (p=.003). The hypothesis 1-2 that after carrying out pelvic muscle exercise program on women with stress urinary incontinence, the situation scores of urinary incontinence would reduce compared to before the exercise was supported(p=.044). The hypothesis 2 that after carrying out pelvic muscle exercise program on women with stress urinary incontinence, the amount of urinary incontinence would reduce compared to before the exercise was supported(p=.001). The hypothesis 3 that after carrying out pelvic muscle exercise program on women with stress urinary incontinence, the maximum vaginal contraction pressure would increase compared to before the exercise was supported (p=.012). These results suggest that pelvic muscle exercise program has an effect on women with stress urinary incontinence in the degree and amount of urinary incontinence and maximum vaginal contraction pressure. So it is judged that training women with stress urinary incontinence for pelvic muscle exercise is an effective nursing intervention strategy in order to care urinary incontinence.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.239-240
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• 2008

• Transactions of Materials Processing
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• v.18 no.1
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• pp.20-25
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• 2009

A finite element analysis was carried out for a 4:1 planar contraction die for polymer melts using the viscoelastic constitutive equation of Leonov. Viscoelastic fluids showed significant differences in pressure drop and birefringence in contraction and expansion flows. The pressure drop was higher and the birefringence smaller in expansion than in contraction flow. The difference increased with increasing flow rate. The nonlinear Leonov model was shown to describe the viscoelastic effects observed in experiments.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.2
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• pp.221-232
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• 2006

The purpose of this study was to investigate the effect of step-curing mode on polymerization shrinkage and contraction of composite resin restoration. Class I cavities were prepared on the extracted human premolars. The cavities were ailed with Filtek $Z-250^{TM}$ (hybrid resin, 3M ESPE, USA) and Filtek $flow^{TM}$ (flowable resin, 3M ESPE, USA) and cured with one of the following irradiation modes; Halogen 40sec with continuous curing, LED 10sec with continuous curing, and LED 13sec with step-curing. Contraction stress was measured with strain gauge which was connected to TML $Datalogger^{TM}$ (TDS-102, SOKKI, Japan) and resin-dentin interfaces were observed by scanning electron microscope. The results of present study can be summarized as follows : 1. Composite resin restoration showed transient expansion just after irradiation of curing light. Contraction stress was increased rapidly at the early phase of polymerization and reduced slowly as time elapsed (P<0.05) 2. $Filtek\;flow^{TM}$ showed lower contraction stress than Filtek $Z-250^{TM}$ regardless of curing modes. 3. LED step-curing mode showed lowest contraction stress in Filtek $Z-250^{TM}$ compared with other curing modes(P<0.05). 4. LED step-curing mode showed lowest contraction stress in $Filtek\;flow^{TM}$ compared with other curing modes(P<0.05), but difference in contraction stress was not so greate as in $Filtek\;Z-250^{TM}$. 5. Polymerization of composite resin by LED light with step-curing mode and halogen light with continuous ode resulted in better marginal sealing than LED light with continuous mode.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.2
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• pp.233-243
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• 2006

The aim of this study was to investigate the relationship between the C-factor and shrinkage strain values of composite resin and examine the strain values in different incremental filling techniques. Experiment consisted two aims. First, we compared with strain value in two different C-factors(3.7 and 1.0). Second, we examined the strain values in three different filling techniques. The results of the present study can be summarized as follows : 1. High C-factor groups showed higher contraction stress values than low C-factor groups at 900 sec after polymerization. 2. Hybrid resin showed higher contraction stress values than flowable resin in high C-factor cavities. But contraction stress was not revealed significant difference between hybrid resin and flowable resin in low C-factor cavities (P>0.05). 3. Bulk felling with hybrid resin(Group 1) showed high contraction stress and lining with flowable resin followed hybrid resin (Group 5) showed lower contraction stress. 4. Contraction stress were increased during 900 sec after polymerization in high C-factor groups but decreased gradually after 900 sec. 5. Low C-factor groups showed tight marginal seal between resin and cavity wall but high C-factor groups showed gaps formed between resin and cavity wall in part. On the basis above results, layering techniques in high C-factor cavity showed advantages in reducing contraction stress and gap formation between cavity wall and resin restoration.

• Structural Engineering and Mechanics
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• v.19 no.6
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• pp.707-720
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• 2005

The bending stress formula that taking into account the transverse deformation is developed for plane-curved, untwisted isotropic beams subjected to loadings that result in deformations in the plane of curvature. In order to account the transverse Poisson contraction effect, a new constitutive relation between force resultants, moment resultants, mid-plane strains and deformed curvatures for a curved plate is derived in a $6{\times}6$ matrix form. This constitutive relation will provide the fundamental basis to the analyses of curved structures composing of isotropic or anisotropic materials. Then, the bending stress formula of a curved isotropic beam can be deduced from this newly developed curved plate theory. The stress predictions by the present analysis are compared to those by the analysis that neglected the Poisson contraction effect. The results show that the Poisson effect becomes more significant as the Poisson ratio and the curvature are getting larger.