• 한국정밀공학회지
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• 제20권11호
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• pp.142-149
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• 2003

Domain switching effect on crack growth in ferroelectric ceramics under combined electric and mechanical loading is investigated. The shape and size of the switching zone is shown to depend strongly on the relative magnitude between the applied electric field and stress field as well as on the ratio of the coercive electric field to the yield electric field. The toughening mechanism is thought to be ferroelectric domain switching leading to the development of a process zone around the crack. Crack-tip stress intensity factor induced by domain switching for the steady state crack growth is numerically obtained.

• Earthquakes and Structures
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• 제6권3호
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• pp.251-266
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• 2014

Dynamic analyses for a suite of ground of motions were conducted on concrete gravity dam sections to examine the earthquake induced stresses and effective damping. For this purpose, frequency domain methods that rigorously incorporate dam-reservoir-foundation interaction and time domain methods with approximate hydrodynamic foundation interaction effects were employed. The maximum principal tensile stresses and their distribution at the dam base, which are important parameters for concrete dam design, were obtained using the frequency domain approach. Prediction equations were proposed for these stresses and their distribution at the dam base. Comparisons of the stress results obtained using frequency and time domain methods revealed that the dam height and ratio of modulus of elasticity of foundation rock to concrete are significant parameters that may influence earthquake induced stresses. A new effective damping prediction equation was proposed in order to estimate earthquake stresses accurately with the approximate time domain approach.

• 대한가정학회지
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• 제43권1호
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• pp.35-51
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• 2005

The purpose of this study was to investigate the effects of marital parenting stress with preschool children on parenting attitudes, as measured by the 'Parent As A Teacher Inventory' (PAAT). From the mothers in Daegu, with 3-to 6-year-old preschool children, 138 subjects were selected. The major findings of this study were as follows. First, there was no significant difference in the maternal parenting stress according to demographic variables. Second, there were significant differences in the parenting attitudes according to the child's age, income, parent's occupation, and maternal educational level. Third, the child's domain of parenting stress affected the control and teaching/learning area of parenting attitudes. The parent's domain of parenting stress affected the creativity, frustration, and control area of parenting attitudes.

• Coupled systems mechanics
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• 제11권3호
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• pp.199-215
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• 2022

The present paper deals with the axisymmetric deformation in homogeneousisotropic thermoelastic solid with two temperatures, with and without energy dissipation using modified couple stresstheory. The effect of energy dissipation and two temperature isstudied due to the concentrated normalforce, normalforce overthe circularregion, thermal pointsource and thermalsource over the circular region. The Laplace and Hankel transform techniques have been used to find the solution to the problem. The displacement components, conductive temperature distribution, stress components and couple stress are computed in the transformed domain and further calculated in the physical domain using numerical inversion techniques. Effects of two temperature and energy dissipation on the conductive temperature,stress components and couple stress are depicted graphically.

• Steel and Composite Structures
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• 제45권6호
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• pp.851-863
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• 2022

This research deals with the study of the Thomson heating effect in magneto-thermoelastic homogeneous isotropic rotating medium, influenced by linearly distributed load and as a result of modified couple stress theory. The charge density is taken as a function of the time of the induced electric current. The heat conduction equation with energy dissipation and with hyperbolic two-temperature (H2T) is used to formulate the model of the problem. Laplace and Fourier transforms are used to solve this mathematical model. Various components of displacement, temperature change, and axial stress as well as couple stress are obtained from the transformed domain. To get the solution in physical domain, numerical inversion techniques have been employed. The Thomson effect with GN (Green-Nagdhi) -III theory and Modified Couple Stress Theory (MCST) is shown graphically on the physical quantities.

• 여성건강간호학회지
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• 제14권1호
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• pp.56-65
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• 2008

Purpose: The study was to develop an instrument to measure grandmothering stress for Korean day-care grandmothers and to test the validity and reliability of the instrument Method: The items of the instrument were based on a literature review and secondary data, After content validity tests and a pilot test, 20 items were developed. In order to test the reliability and validity of the scale, data were collected from 126 grandmothers. Result: After a factor analysis, five factors and 15 items were selected. These explained 67.2% of the total variance. The first domain was termed 'Health problems', and explained 18.1 % of the total variance, and the second domain of 'Possibility of role substitution' explained 13.8%. The third and the fourth domains were 'Relations with adult children' and 'Grandchildren's characteristics' explaining 12.5% and 12.1 %, respectively. The last domain explained 10.8% of the total variance with the theme 'Restriction of social life' After accomplishing the reliability analysis, Cronbach's alpha coefficient was determined to be .75. Conclusions : This initial step in the development of a Grandmothering Stress Index is valuable to reflect the subject of Grandmothering stress in senior citizens in Korea. Future study should to refine the constitution of the instrument.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 춘계학술대회 논문집
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• pp.478-481
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• 2004

This study presents the combined effect of electric Held application and mechanical compressive stress loading on deformation in a multilayer ceramic actuator, designed with stacking alternatively 0.2(PbMn$\_$1/3/Nb$\_$2/3/O$_3$)-0.8(PbZr$\_$0.475/Ti$\_$0.525/O$_3$) ceramics and Ag-Pd electrode. The deformation behaviors were thought to be attributed to relative 180$^{\circ}$domain quantities which is determined by pre-loaded stress and electric field. The non-linearity of piezoelectricity and strain are dependent upon the young's modulus resulting from the domain reorientation.

• 대한전기학회논문지
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• 제40권5호
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• pp.496-500
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• 1991

The effects of annealing with and without magnetic field on magnetic properties of amorphous Fe-B-Si cores have been investigated as a function of toroidal stress. By decreasing the toroidal stress, the magnetic properties of the amorphous ribbon have beenimproved. Near 180 domain walls exist in the thermally annealed toroidal cores, but the domain walls exist in the thermally annealed toroidal cores, but the domain walls are not parallel to the longitudinal direction of the ribbon. In the specimen annealed with a magnetic field strength of 10 Oe in the longitudinal ribbon length axis, the domains are nearly parallel to the longitudinal direction due to the field induced uniaxial anisotropy resulting in further increase in the remanent magnetization and decrease in the coercive force and loss.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2007년도 정기 학술대회 논문집
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• pp.495-500
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• 2007

A Meshfree is a method used to establish algebraic equations of system for the whole problem domain without the use of a predefined mesh for the domain discretization. A point interpolation method is based on combining radial and polynomial basis functions. Involvement of radial basis functions overcomes possible singularity. Furthermore, the interpolation function passes through all scattered points in an influence domain and thus shape functions are of delta function property. This makes the implementation of essential boundary conditions much easier than the meshfree methods based on the moving least-squares approximation. This study aims to investigate a stress analysis of structural element between a meshfree method and the finite element method. Examples on cantilever type plate and stress concentration problems show that the accuracy and convergence rate of the meshfree methods are high.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• 제14권2호
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• pp.218-228
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• 2003

목 적：본 연구에서는 정신과를 방문한 아동들의 정서 및 행동 문제와 어머니의 우울증, 양육 스트레스간의 관계를 알아보고, 특히, 이러한 변인들이 어머니의 양육 스트레스에 어떠한 영향을 주는지 알아보았다. 방 법：DSM-IV 진단 준거에 근거한 정신과 전문의의 소견과 심리학적 평가에 의해 외현화 행동 장애, 내면화 행동 장애, 혼재형 행동 장애로 각각 진단된 73명의 아동과 그 어머니들을 대상으로 하였다. 모든 아동의 어머니는 다면적 인성검사(MMPI)와 한국아동인성검사(KPI-C) 및 양육스트레스 척도(PSI)를 작성하였고, 변량분석, 상관분석, 단계적 회귀분석을 실시하였다. 결 과：외현화 행동 장애와 내면화 행동 장애, 혼재형 행동 장애를 가진 아동의 각 집단별 어머니들의 우울감은 유의미한 차이를 보이지 않았다. 양육 스트레스를 종속변인으로한 2요인 변량분석 결과, 외현화 행동장애와 혼재형 행동장애에서 아동 영역 양육 스트레스 하위 요인 중 주의산만/과잉행동 요인이 내현화 행동장애 아동보다 더 심각한 스트레스로 작용하였고, 어머니의 우울 여부의 주효과는 전반적 양육 스트레스 총점, 부모 영역 양육 스트레스 총점, 부모 영역 양육 스트레스의 하위 요인 중 우울, 부모의 건강, 배우자와의 관계의 요인에서 각각 유의미하였다. 아동의 증상 심각도가 양육 스트레스에 미치는 영향을 알아본 결과, 아동 영역 양육 스트레스에 대해서는 아동의 과잉행동과 불안이, 부모 영역 양육 스트레스에 대해서는 어머니의 우울 수준이 각각 유의미한 효과를 갖는 것으로 나타났다. 결 론：본 결과는 우울한 어머니들의 경우, 아동의 증상 심각도 보다는 어머니의 우울 수준이 전반적인 양육 스트레스에 더 많은 영향을 미치므로, 우울한 어머니들에서는, 아동의 증상에 대한 치료와는 별도로 어머니의 심리적 적응에 개별적인 치료적 접근이 필요함을 시사한다.