• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.9
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• pp.546-550
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• 2017

Ferroelectric properties are governed by domain structures and domain wall motions, so it is of significance to understand domain evolution processes under mechanical stress. In the present study, in situ piezoresponse force microscopy (PFM) observation under compressive stress was carried out for a near-morphotropic PZT. Both $180^{\circ}$ and $non-180^{\circ}$ domain structures were observed from PFM images, and their habit planes were identified using electron backscatter diffraction in conjunction with PFM data. By externally applied mechanical stress, needle-like $non-180^{\circ}$ domain patterns were broadened via domain wall motions. This was interpreted via phenomenological approach such that the total energy minimization can be achieved by domain wall motion rather than domain nucleation mainly due to the local gradient energy. Meanwhile, no motion was observed from curvy $180^{\circ}$ domain walls under the mechanical stress, validating that $180^{\circ}$ domain walls are not directly influenced by mechanical stress.

• The Journal of Korean Academic Society of Nursing Education
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• v.4 no.2
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• pp.317-330
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• 1998

A descriptive-explanatory design was employed in this study. The purpose of this study was identify the level of assertiveness and clinical stress and the relationships between assertiveness and clinical stress in nursing students. A convenient sample of 143 nursing students was used for the study. The results of this study are as follows : 1) The level of assertiveness of nursing students was 3.65 in domain of contents, 3.68 in domain of voice, and 4.13 in domain of body language. Thus the level of asertiveness of nursing students was higher in body language. 2) The level of clinical stress of nursing students was 3.73 in domain of clinical education and evaluation by professors, 3.59 in domain of nurses, 3.32 in domain of human relationships, and 3.30 in domain of environment. Thus the level of clinical stress of nursing students was higher in clinical education and evaluation by professors. 3) The assertiveness of nursing students was found significantly related to human relationships. 4) The clinical stress of nursing students was found significantly related to satisfaction of nursing, satisfaction of clinical practice and priority of candidate for nursing. 5) The assertiveness of nursing students was not found significantly related to clinical stress in nursing students.

• Geomechanics and Engineering
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• v.19 no.5
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• pp.369-381
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• 2019

The objective of this paper is to study the two dimensional deformation in transversely isotropic thermoelastic medium without energy dissipation due to time harmonic sources using new modified couple stress theory, a continuum theory capable to predict the size effects at micro/nano scale. The couple stress constitutive relationships have been introduced for transversely isotropic thermoelastic medium, in which the curvature tensor is asymmetric and the couple stress moment tensor is symmetric. Fourier transform technique is applied to obtain the solutions of the governing equations. Assuming the deformation to be harmonically time-dependent, the transformed solution is obtained in the frequency domain. The application of a time harmonic concentrated and distributed sources have been considered to show the utility of the solution obtained. The displacement components, stress components, temperature change and couple stress are obtained in the transformed domain. A numerical inversion technique has been used to obtain the solutions in the physical domain. The effects of angular frequency are depicted graphically on the resulted quantities.

• Nuclear Engineering and Technology
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• v.30 no.3
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• pp.202-211
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• 1998

Interfacial stresses at two-material interfaces and initial displacement field over the entire domain are obtained by modifying the potential energy functional with a penalty function, which enforces continuity of the stresses at the interface of two materials. Based on the initial displacement field and interfacial stresses, a new methodology to generate a continuous stress field over the entire domain has been proposed by combining the modified projection method of stress-smoothing and Loubignac's iterative method of improving the displacement field. Stress analysis is carried out on two examples made of dissimilar materials : one is a two-material cantilever composed of highly dissimilar materials and the other is a zirconium-lined cladding tube made of slightly dissimilar materials. Results of the analysis show that the proposed method provides an improved continuous stress field over the entire domain, and accurately predicts the nodal stresses at the interface, while the conventional displacement-based finite element method produces significant stress discontinuities at the interface. In addition, the total strain energy evaluated from the improved continuous stress field converges to the exact value in a few iterations.

• Corrosion Science and Technology
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• v.7 no.6
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• pp.307-314
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• 2008

The influence of a moist atmosphere on $90^{\circ}$ domain switching under a sustained electric field, stress corrosion cracking of an indentation crack in water and an aggressive solution, and the relation between penetrating crack propagation and domain switching were studied using $BaTiO_3$ single crystal. The results indicate that enlarging the domain switching zone and crack propagation could be facilitated by a moist atmosphere or an aggressive solution due to the indentation residual stress. A moist atmosphere exerts remarkable influence upon the polarization of $BaTiO_3$ single crystal under a sustained electric field, and the surface energy of the c domain was much lower than that of the a domain. Domain switching ahead of a penetrating indentation crack tip was an essential requirement for crack propagation under constant stress.

• Proceedings of the KSPS conference
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• 2002.11a
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• pp.64-69
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• 2002

This study concerns the constraints of English Poetic Meter. In English poems, the metrical pattern doesn't always match the linguistic stress on the lines. These mismatches are found differently among the poets. For the lexical stress mismatched with the weak metrical position, $*W{\Rightarrow}{\;}Strength$ is established by the concept of the strong syllable. The peaks of monosyllabic words mismatched with the weak metrical position are divided according to which side of the boundary of a phonological domain they are adjacent to. Adjacency Constraint I is suggested for the mismatched peak which is adjacent to the left boundary of a phonological domain; *Peak] and Adjacency ConstraintII for the mismatched peak which are adjacent to the right boundary of a phonological domain. These constraints are various according to the poets(Pope, Milton and Shakespeare) : *[Peak [-stress], $W{\Rightarrow}{\;}*Strength$ and *Peak] in Pope; *[+stress][Peak [-stress] and *Peak] in Milton ; *[+stress][Peak [-stress], $W{\;}{\Rightarrow}{\;}*Strength$ and ACII in Shakespeare.

• Korean Journal of English Language and Linguistics
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• v.2 no.4
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• pp.555-574
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• 2002

This study concerns the constraints of English Poetic Meter. In English poems, the metrical pattern doesn't always match the linguistic stress on the lines. These mismatches are found differently among the poets. For the lexical stress mismatched with the weak metrical position, W⇒ Strength is established by the concept of the strong syllable. The peaks of monosyllabic words mismatched with the weak metrical position are divided according to which side of the boundary of a phonological domain they are adjacent to. Adjacency Constraint I is suggested for the mismatched peak which is adjacent to the left boundary of a phonological domain; /sup */Peak] and Adjacency ConstraintⅡ for the mismatched peak which is adjacent to the right boundary of a phonological domain. These constraints are various according to the poets (Pope, Milton and Shakespeare) : /sup */[Peak [-stress], /sup */W⇒ Strength and /sup */Peak] in Pope; /sup */[+stress][Peak[-stress] and /sup */Peak] in Milton; /sup */[ +stress][Peak[-stress], /sup */W⇒Strength and Adjacency ConstraintⅡ in Shakespeare.

• The Journal of Korean Academic Society of Nursing Education
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• v.7 no.1
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• pp.7-21
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• 2001

The purpose of this study was identify the level of stress, anger and anger expression in the clinical setting and identify the relation ships between anger and stress of nursing students in the clinical setting. A convenient sample of 213 junior college of nursing students was used for the study. The data were analyzed by descriptive statistics and Pearson Correlation Coefficients. The results of this study were summarized as follows : 1. The average stress score in the clinical setting of subjects was 3.87. The higher level of stress in the clinical setting was 4.10 in domain of nurses, 4.10 in domain of human relationships, 4.07 in domain of report and 3.89 in domain of relationship between nursing theory and practice. 2. The average state-anger score of subjects was 1.54. 3. The average anger-out score of anger expression mode was 1.66 and 2.36 in anger-in. 4. The state-anger was found significantly related to stress of nursing students in the clinical setting (r=0.256 p<0.001). In the relationship between state- anger and stress in the clinical setting, environment, patient relationship, between nursing theory and practice, nurses, report, orientation were significantly positive correlation . 5. The anger-out of anger expression mode was not found significantly related to stress of nursing students in the clinical setting. 6. The anger-in of anger expression mode was found significantly related to stress of nursing students in the clinical setting (r=0.205 p<0.01). In the relationship between anger-in of anger expression mode and stress in the clinical setting, environment, patient, nurses, human relationships, conference were significantly positive correlation.

• The Korean Journal of Community Living Science
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• v.17 no.1
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• pp.39-53
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• 2006

The purpose of this study was to examine the relation of elementary school children's stress and coping behavior in urban and rural areas. The subject included 286 children selected from 4 elementary schools in urban and rural areas. The instruments included the children's stress index and coping behavior questionnaire of the elementary school children. The statistics used from this data were t-test, one-way ANOVA(Duncan test), correlation analysis and multiple regression analysis. This study showed significant differences between urban and rural children's stress in school attainment domain, teacher-school domain, home environment domain and surroundings domain. And urban and rural children was different in active, passive/avoidant and aggressive coping behavior. The stress of urban's children was influenced significantly by the grade and school attainment variales, and the rural children's stress was influenced significantly by the gender variable. The coping behavior of urban's children was influenced by the gender, grade and school attainment variables, and also the rural children's coping behavior was influenced by the above variables. Correlation analysis indicated that children's stress and aggressive coping behavior were relative positive high correlation in urban areas, and children's stress and passive/avoidant coping behavior were positive high correlation in rural areas. It was also found that school attainment, aggressive coping behavior and passive/avoidant coping behavior were significant predictors of urban children's stress, and gender, passive/avoidant coping behavior and aggressive coping behavior were significant predictors of rural children's stress.

• Structural Engineering and Mechanics
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• v.10 no.4
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• pp.393-404
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• 2000

Linear stress analysis without body force can be easily solved by means of the boundary element method. Some cases of linear stress analysis with body force can also be solved without a domain integral. However, domain integrals are generally necessary to solve the linear stress problem with arbitrary body forces. This paper shows that the linear stress problem with arbitrary body forces can be solved approximately without a domain integral by the triple-reciprocity boundary element method. In this method, the distribution of arbitrary body forces can be interpolated by the integral equation. A new computer program is developed and applied to several problems.