• The Korean Journal of Nuclear Medicine
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• v.21 no.1
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• pp.39-46
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• 1987

The stress fracture is a disease caused by and abnormal stress to the normal bone with constant, repeated pull. Early detection of stress fracture plays an important role in treatment and prevention of its complication. Bone scintigraphy was performed to evaluate 18 patients with stress fracture of the lower extremities from May, 1985 to April, 1987, in the Department of Internal Medicine of National Police Hospital. The results were as follows: 1) Seventeen of the 18 cases showed positive bone scans at the initial study performed from 1 week to S months after the onset of symtom. 2) Ten of the 18 patients had findings of stress fracture at the initial X-ray film. Two out of 8 negative case revealed positive findings in the follow-up studies. 3) The bone scans in the 2 cases taken 5 months after the onset of symton; the one showed only slightly increased radiouptake, the other showed no abnormal findings. In conclusion, bone scanning is a more sensitive indicator of early stress fracture than radiologic study. The healing phase is characterized by a gradual decline in radioactivity at the fracture site in concordance with subsidence of symptom.

• Restorative Dentistry and Endodontics
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• v.37 no.2
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• pp.74-78
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• 2012

Objectives: This study aimed to evaluate the relationship between the cyclic fatigue of a K3 file and internal stress intentionally induced until the activation of the autostop function of the torque-controlled motor. Materials and Methods: K3 (Sybron Endo) .04 and .06 taper, size 25, 30, 35, 40 and 45 were used in this study. To give the internal stress, the K3 files were put into the .02 taper Endo-Training-Bloc (Dentsply Maillefer) until the activation of the auto-stop function of the torque-controlled motor. The rotation speed was 300 rpm and torque value was 1.0 $N{\cdot}cm$. K3 were grouped by the number of induced internal stress and randomly distributed to 4 experimental groups (n = 10, Stress 0 [control], Stress 1, Stress 2 and Stress 3). For measuring the cyclic fatigue failure, the K3 files were worked against a sloped glass block and time for file separation was recorded. Data was statistically analyzed Statistical analyses were performed using two-way ANOVA and Duncan post-hoc test at p < 0.05 level. Results: Except .04 taper size 30 in Stress 1 group, there were statistically significant differences in time for file separation between control and all experimental groups. K3 with .04 taper showed higher cyclic fatigue resistance than those of .06 taper. Conclusion: In the limitation of this study, the cyclic fatigue of the K3 file was influenced by the accumulated internal stress from use until the auto-stop function was activated by the torque-controlled motor. Therefore, clinicians should avoid the reuse of the K3 file that has undergone auto-stops.

• Corrosion Science and Technology
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• v.11 no.6
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• pp.275-279
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• 2012

Ni-W alloy deposits have lately attracted the interest as an alternative surface treatment method for hard chromium electrodeposits because of higher wear resistance, hardness at high temperature, and corrosion resistance. This study deals with influences of process variables, such as electodeposition current density, plating temperature and pH, on the internal stress of Ni-W nanocrystalline deposits. The internal stress was increased with increasing the applied current density. With increasing applied current density, the grain size of the deposit decreases and concentration of hydrogen in the deposit increases. The subsequent release of the hydrogen results in shrinkage of the deposit and the introduction of tensile stress in the deposit. Consequently, for layers deposited at high current density, cracking occurs readily owing to high tensile stress value. By increasing the temperature of the electrodeposition from $60^{\circ}C$ to $80^{\circ}C$, the internal stress was decreased. It seems that an increase in the number of active ions overcoming the activation energy at elevated temperature caused a decline in the concentration polarization and surface diffusion. It decreased the level of hydrogen absorption due to the lessened hydrogen evolution reaction. Therefore, the lower level of hydrogen absorption degenerated the hydride on the surface of the electrode, resulting in the reduction of the internal stress of the deposits. By increasing the pH of the electrodeposition from 5.6 to 6.8, the internal stress in the deposits were slightly decreased. It is considered that the decrease in internal stess of deposits was due to supply of W complex compound in cathode surface, and hydrogen ion resulted from decrease of activity.

• Human Ecology Research
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• v.57 no.4
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• pp.485-498
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• 2019

This study examined the mediating effect of internal locus of control in the relationship between family and friend support and acculturative stress of North Korean adolescent refugees. Participants consisted of 101 North Korean adolescent refugees (40 males and 61 females) aged 13 to 24, who live in Seoul, Gyeonggi Province, and Busan. SPSS 25.0 and Mplus 5.12 were used to analyze data. Descriptive statistics and Pearson's correlation coefficients were calculated and structural equation modeling (SEM) examined the mediating effect. The results of this study are as follows. First, a higher level of family support and friend support were associated with a higher level of internal locus of control. A higher level of internal locus of control was associated with a lower level of acculturative stress among North Korean adolescent refugees. Second, the level of internal locus of control mediated the relationship between friend support and acculturative stress. This study is meaningful in that it examines the specific paths affecting acculturative stress of North Korean adolescent by examining family and friend support, which are environmental factors, and internal locus of control, which is internal factor of individuals. The study results suggest that improving friend support as well as increasing the level of internal locus of control for North Korean adolescent refugees can be an effective way to prevent or intervene acculturative stress.

• The Journal of Internal Korean Medicine
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• v.25 no.1
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• pp.1-15
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• 2004

Objective : This study was aimed to evaluate the anti-starvation stress effect of Liriopis Tuber on mice. Method : The first experiment was done to mice which have a high corticosterone level at a short term starvation. The plasma corticosterone level of each mouse was measured over time at 12, 24, 36, 48, 72 hours of starvation respectively. The second experiment was done in the two groups(LT A and LT B) of mice which were in famine for 36.5 hours after being administered Liriopis Tuber three times with different doses(LT A: 1.0 g/.kg and LT B: 3.0g/kg) for three days. The plasma corticosterone levels and rectal temperature were measured when a 36.5-hour of starvation period was finished. Results : 1. The corticosterone level in the mice was significantly increased after a 36.5-hour of starvation. (P<0.001). 2. The plasma corticosterone level was decreased significantly in the group of 3.0g/kg, compared to the control group.(P<0.05) 3. The rectal temperature in the groups of 1.0g/kg and 3.0g/kg were increased slightly in both group. But the two groups didn't show significant change. Conclusion: Based on the above results, Liriopis Tuber might have anti-starvation stress effect and it may be used as anti-starvation stress medicine and anti-stress medicine. Conclusion : Based on the above results, Liriopis Tuber might have anti-starvation stress effect and it may be used as anti-starvation stress medicine and anti-stress medicine.

• Transactions of the Korean Society of Mechanical Engineers
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• v.7 no.2
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• pp.123-129
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• 1983

The effect of the micro-internal stress which is induced in the ferrite grain by plastic constraint, on fracture behavior was investigated. The specimen used has combined microstructure with matrix of ferrite encapsulated by second phase of martensite. The micro-internal stress in the ferrite grain was estimated using a simple mechanical model, and its effect on micro and macro fracture behaviors was discussed. The results obtained are summarized as follows; The micro-internal stress promotes the formation of cleavage cracks in the ferrite during deformation. Consequently, it was concluded that the internal stress is one of the significant factors which cause the fracture ductility to decrease.

• Journal of the Korean Ceramic Society
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• v.33 no.1
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• pp.49-55
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• 1996

The aim of this study is to investigate the change of bending strength and fatigue strength in the unpoled and poled Pb(Zr, Ti)O3 ferroelectrics of tetragonal morphotropic phase boundary (MPM) and rhombohedral com-position in terms of internal stress which is measured by XRD method. Before poling treatment the highest bending strength was found in rhombohedral composition. After poling treatment the bending strength decreas-ed in all compositions but it decreased most remarkably in tetragonal composition. The most prominent de-crease of bending strength after poling treatment in tetragonal was attributed to the occurrence of microcracks due to highanisotropic internal stress around grain boundary which was induced of bending strength after poling in MPB and rhombohedral composition was not due to the occurrence of microcracks but to the increase in tensile internal stress perpendicular to the direction of crack propagation by domain alignment. Fatigue strength was higher before poling treatment than after poling treatment for various compositions.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.2
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• pp.62-67
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• 2013

The influence of internal stress and joint strength(shear, tensile) according to the deposition conditions was investigated by the Polyimide substrate and ZnO thin film. Deposition thickness and temperature affect the internal stress and the internal stress was minimum at the 60nm and $200^{\circ}C$ of the deposition conditions. Tensile strength is large at the deposition condition that shear strength is large and the shear strength was about 50% of the tensile strength. The shear strength and tensile strength were large at deposition condition that internal stress was small. Crack occurred near the joint interface of Polyimide substrate and progressed along the interface until the final fracture.

• Restorative Dentistry and Endodontics
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• v.37 no.2
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• pp.79-83
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• 2012

Objectives: The purpose of this study was to evaluate the relation between intentionally induced internal stress and cyclic fatigue failure of .06 taper ProFile. Materials and Methods: Length 25 mm, .06 taper ProFile (Dentsply Maillefer), and size 20, 25, 30, 35 and 40 were used in this study. To give the internal stress, the rotary NiTi files were put into the .02 taper, Endo-Training-Bloc (Dentsply Maillefer) until auto-stop by torque controlled motor. Rotary NiTi files were grouped by the number of induced internal stress and randomly distributed among one control group and three experimental groups (n = 10, Stress 0 [control], Stress 1, Stress 2 and Stress 3). For cyclic fatigue measurement, time for separation of the rotary NiTi files was recorded. The fractured surfaces were observed by field emission scanning electron microscope (FE-SEM, SU-70, Hitachi). The time for separation was statistically analyzed using two-way ANOVA and post-hoc Scheffe test at 95% level. Results: In .06 taper ProFile size 20, 25, 30, 35 and 40, there were statistically significant difference on time for separation between control group and the other groups (p < 0.05). Conclusion: In the limitation of this study, cyclic fatigue failure of .06 taper ProFile is influenced by internal stress accumulated in the files.

• Journal of the Korean Home Economics Association
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• v.47 no.4
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• pp.37-48
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• 2009

This purpose of this study was to examine the connections between positive maternal psychology, internal control, and parenting stress of mothers with young children. The subjects were 398 mothers living in Buchon city. Collected data were subjected to descriptive statistical analysiss, Pearson’s correlation, and multiple regression analysis. Results showed that employed mothers had higher positive psychology and lower parenting stress than unemployed mothers. In addition, positive maternal psychology, internal-external control, and parenting stress were all related to each other. In particular, positive psychology was the strongest predictor for parental stress.