• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.4
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• pp.285-296
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• 2005

Reduced pressure chemical vapor deposition technology has been used to study SiGe heterostructure epitaxy and device issues, including SiGe relaxed buffers, proper control of Ge component and crystalline defects, two dimensional delta doping, and their influence on electrical properties of devices. From experiments, 2D profiles of B and P presented FWHM of 5 nm and 20 nm, respectively, and doses in 5×10/sup 11/ ∼ 3×10/sup 14/ ㎝/sup -2/ range. The results could be employed to fabricate SiGe/Si heterostructure field effect transistors with both Schottky contact and MOS structure for gate electrodes. I-V characteristics of 2D P-doped HFETs revealed normal behavior except the detrimental effect of crystalline defects created at SiGe/Si interfaces due to stress relaxation. On the contrary, sharp B-doping technology resulted in significant improvement in DC performance by 20-30 ％ in transconductance and short channel effect of SiGe HMOS. High peak concentration and mobility in 2D-doped SiGe heterostructures accompanied by remarkable improvements of electrical property illustrate feasible use for nano-sale FETs and integrated circuits for radio frequency wireless communication in particular.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.5
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• pp.345-352
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• 2014

In this paper, the CAD data for the optimal shape design obtained by isogeometric shape optimization is directly used to fabricate the specimen by using 3D printer for the experimental validation. In a conventional finite element method, the geometric approximation inherent in the mesh leads to the accuracy issue in response analysis and design sensitivity analysis. Furthermore, in the finite element based shape optimization, subsequent communication with CAD description is required in the design optimization process, which results in the loss of optimal design information during the communication. Isogeometric analysis method employs the same NURBS basis functions and control points used in CAD systems, which enables to use exact geometrical properties like normal vector and curvature information in the response analysis and design sensitivity analysis procedure. Also, it vastly simplify the design modification of complex geometries without communicating with the CAD description of geometry during design optimization process. Therefore, the information of optimal design and material volume is exactly reflected to fabricate the specimen for experimental validation. Through the design optimization examples of elasticity problem, it is experimentally shown that the optimal design has higher stiffness than the initial design. Also, the experimental results match very well with the numerical results. Using a non-contact optical 3D deformation measuring system for strain distribution, it is shown that the stress concentration is significantly alleviated in the optimal design compared with the initial design.

• Child Health Nursing Research
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• v.2 no.1
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• pp.55-68
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• 1996

Although nursing researchers have performed studies on parent-child relationship actively since early 1980s in Korea, nothing hasn't been tried on the analysis of the contents of researches. We researchers tried examining the trend of researches by investigating treaties on mother-child relationship conducted from 1981 to 1994. The purpose of this study was to analyze the trend of research on the mother-child relationship and to suggest direction for future study. The total numbers of the studies were 27 cases, These studies were analyzed for 1) time of publication 2) research design 3)main concept 4)thesis for a degree or nondegree 5) measurement tool The finding of the analysis were as follows. 1) In the chronological situation, the research on mother-child relationship began to perform in 1981 in the country and had been made most for five years to 1986 with 14 treaties and has decreased since 1990. 2) In the research plan, there are 21 survey(the most) ,5 quasi experimental(before 1986), 1 qualitative. 3) In the subject, the researches on mother-child are the most, 22 and of them 17 treaties on normal infant,4 comparative research on high risk infant and normal infant,5 treaties on mother, 4) The conception of mother-child relationship was used as various conceptions such as affection, union, bonding in early research of 1980s, but it hasn't been used as union bonding but studied mostly as the conception of 'mother-child interaction'since 1986. 5) The measurement tool of research was used variously, the Cropley's tool was used in early 1980s, but Walker's MIPS, Barnard's NCAST were used mostly in 1990. 6) Mother-child interaction influence on mother's self-conception, stress, care and feeding of child, frequency of delivery, planned pregnancy and delivery and health condition of child, birth weight, fetal period, period of mother-child life. Aspects of mother-child interaction composed on visual contact, looking at each other, skinship and caress with finger and fingertip. The leading action of mother-child interaction was mostly uttering action. 7) I suggest that the program for professional education is necessary for the establishment of the aspects of mother-child interaction.

• Applied Microscopy
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• v.35 no.3
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• pp.165-176
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• 2005

Studies on molecular plasticity of Bermann glia (BG) after harmaline-induced Purkinje cell (PC) degeneration in the rat cerebellum. The intimate structural relationship between BG and PC, evidenced by the sheathing of the PC dendrites by veil-like process from the BG has been suggestive of the close functional relationship between these two cell types. However, little is known about metabolic couplings between these cells. This study designed to investigate molecular plasticity of BG in the rat cerebellum in which PCs were chemically ablated by harmaline treatment. Immunohistochemical examination reveals that harmaline induced PC degeneration causes a marked glial reaction in the cerebellum with activated BG and microglia aligned in parasagittal stripes within the vermis. In these strips, activated BG were associated with upregulaion of metallotheionein, while GLAST and was down regulated, as compared with nearby intact area where both BG are in contact with PCs. The data from this study demonstrate that BG can change their phenotypic expression when BG loose their contact with PCs. It is conceivable that activated BG may upregulate structural proteins, metallothionein expression to use for their proliferation and hypertrophy; metallothionein expression to cope with oxidative stress induced by PC degeneration and microglial activation. On the contrary, BG may down regulated expression of GLAST because sustained loss of contact with PCs would eliminate the necessity for the cellular machinery involved glutamate metabolism. In conclusion, BG might respond man to death of PCs by undergoing a change in metabolic state. It seems possible that signaling molecules released from PCs regulates the phenotype expression of BG. Also ultrastructures in the organelles of normal PC and BG are distinguished by mitochondrial appearance, and distributed vesicles at the synaptic area in the cytoplasm.