• Journal of the Microelectronics and Packaging Society
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• v.13 no.1 s.38
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• pp.7-15
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• 2006

In-situ observation of electromigration in thin film pattern of 63Sn-37Pb solder was performed using a scanning electron microscope system. The 63Sn-37Pb solder had the incubation stage of electromigration for edge movement when the current density of $6.0{\times}10^{4}A/cm^2$ was applied the temperature between $90^{\circ}C\;and\;110^{\circ}C$. The major diffusion elements due to electromigration were Pb and Sn at temperatures of $90-110^{\circ}C\;and\;25-50^{\circ}C$, respectively, while no major diffusion of any element due to electromigration was detected when the test temperature was $70^{\circ}C$. The reason was that both the elements of Sn and Pb were migrated simultaneously under such a stress condition. The existence of the incubation stage was observed due to Pb migration before Sn migration at $90-110^{\circ}C$. Electromigration behavior of 63Sn-37Pb solder had an incubation time in common for edge drift and void nucleation, which seemed to be related the lifetime of flip chip solder bump. Diffusivity with $Z^*$(effective charges number) of Pb and Sn were strongly affect the electromigration-induced major diffusion element in SnPb solder by temperature, respectively.

• Nuclear Engineering and Technology
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• v.47 no.5
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• pp.588-595
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• 2015

This study presents an effective method for additional recovery of residual actinides in liquid electrodes after the electrowinning process of pyroprocessing. The major distinctive feature of this method is a reactor with multiple reaction cells separated by partition walls in order to improve the recovery yield, thereby using the interelement difference in diffusion coefficients within the liquid electrode and controlling the selectivity and purity of element recovery. Through an example of numerical simulation of the diffusion scenarios of individual elements, we verified that the proposed method could effectively separate the actinides (U and Pu) and rare-earth elements contained in liquid cadmium. We performed a five-step consecutive recovery process using a simplified conceptual reaction cell and recovered 58% of the initial amount of actinides (U + Pu) in high purity (${\geq}99%$).

• Journal of Technologic Dentistry
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• v.32 no.4
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• pp.351-356
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• 2010

Purpose: The purpose of this study was to evaluate the fracture strength between the core and veneering ceramic according to 2 core materials, In-Ceram Alumina and In-Ceram Zirconia, fabricated by electro ceramic layering technique. 2 different fixed partial denture cores of three units were veneered by veneering ceramic(Ceranion, Noritake) (n=10). Methods: The fracture strengths between the core and veneering ceramic were measured through the 3 point bending test. The interfaces between the core and veneering ceramic were observed with the X-ray dot mapping of EPMA. Results: The result of fracture strength was observed that IZP group, In-Ceram Zirconia core, had higher fracture strength. IPA group, In-Ceram Alumina core, had fracture strength of 359.9(${\pm}$86.2) N. IZP group, In-Ceram Zirconia core, had fracture strength of 823.2(${\pm}$243.0) N. X-ray dot mapping observation showed that a major element in the core and veneering ceramic of IPA group was alumina and silica, respectively. No binder was observed in interfaces between the core and veneering ceramic, and no ion diffusion or transition was observed between the core and veneering ceramic. However, apparent ion diffusion or transition was observed between the core and veneering ceramic of IZP group.

• Nuclear Engineering and Technology
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• v.50 no.6
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• pp.915-922
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• 2018

Metallic fuel has been considered for sodium-cooled fast reactors because it can maximize the uranium resources. It generates rare earth elements as fission products, where it is reported by aggravating the fuel-cladding chemical interaction at the operating temperature. Rare earth elements form a multicomponent alloy (Ce-Nd-Pr-La-Sm-etc.) during reactor operation, where it shows a higher reaction thickness than a single element. Experiments have been carried out by simplifying multicomponent alloys for mono or binary systems because complex alloys have difficulty in the analysis. In previous experiments, xCe-yNd was fabricated with two elements, Ce and Nd, which have a major effect on the fuel-cladding chemical interaction, and the thickness of the reaction layer reached maximum when the rare earth elements ratio was 1:1. The objective of this study is to evaluate the effect and relationship of rare earth elements on such synergistic behavior. Single and binary rare earth model alloys were prepared by selecting five rare earth elements (Ce, Nd, Pr, La, and Sm). In the single system, Nd and Pr behaviors were close to diffusion, and Ce showed a eutectic reaction. In the binary system, Ce and Sm further increased the reaction layer, and La showed a non-synergy effect.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.2
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• pp.93-103
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• 2023

Warships widely spread numerous chaffs using a blast, which form chaff clouds that create false radar cross-sections to deceive enemy radars. In this study, we established a numerical framework based on a one-way coupling of computational fluid dynamics and discrete element method to simulate the spatiotemporal distribution of chaff clouds for warships in the air. Using the framework, we investigated the effects of wind, initial chaff cartridge angle, and blast pressure on the distribution of chaff clouds. We observed three phases for the chaff cloud diffusion: radial diffusion by the explosion, omnidirectional diffusion by turbulence and collision, and gravity-induced diffusion by the difference in the fall speed. The wind moved the average position of the chaff clouds, and the diffusion due to drag force did not occur. The direction of radial diffusion by the explosion depended on the initial angle of the cartridge, and a more vertical angle led to a wider distribution of the chaffs. As the blast pressure increased, the chaff clouds spread out more widely, but the distribution difference in the direction of gravity was not significant.

• Advances in aircraft and spacecraft science
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• v.5 no.4
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• pp.499-513
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• 2018

One of the major problems in glass fiber reinforced epoxy (GFRE) composite pipes is the durability under water absorption. This condition is generally recognized to cause degradations in strength and mechanical properties. Therefore, there is a need for an intelligent system for detecting the absorption rate and computing the mass of water absorption (M%) as a function of absorption time (t). The present work represents a new non-destructive evaluation (NDE) technique for detecting the water absorption rate by evaluating the dielectric properties of glass fiber and epoxy resin composite pipes subjected to internal hydrostatic pressure at room temperature. The variation in the dielectric signatures is employed to design an electrical capacitance sensor (ECS) with high sensitivity to detect such defects. ECS consists of twelve electrodes mounted on the outer surface of the pipe. Radius-electrode ratio is defined as the ratio of inner and outer radius of pipe. A finite element (FE) simulation model is developed to measure the capacitance values and node potential distribution of ECS electrodes on the basis of water absorption rate in the pipe material as a function of absorption time. The arrangements for positioning12-electrode sensor parameters such as capacitance, capacitance change and change rate of capacitance are analyzed by ANSYS and MATLAB to plot the mass of water absorption curve against absorption time (t). An analytical model based on a Fickian diffusion model is conducted to predict the saturation level of water absorption ($M_S$) from the obtained mass of water absorption curve. The FE results are in excellent agreement with the analytical results and experimental results available in the literature, thus, validating the accuracy and reliability of the proposed expert system.

• Journal of Distribution Science
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• v.14 no.4
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• pp.67-79
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• 2016

Purpose - Over recent years, we have concerned about safety and quality on food products because of delivery complexity. The dependence of foreign food products escalate supply of products. And there are often negligent accident of marine and agricultural products. Therefore, the complexity increases the importance of safety on food and information quality for consumers. In spite of the interest augmentation of various interested parties, there is decrease in reliability and effectiveness, if it would be established without the right directivity. For the study, we tried to examine the first considerations the point of - view in service environment and information quality with accepting and diffusing the Traceability System. Then, we tried to verify the relationships between the factors of TS and the determinants of behavior decision. Next, we made efforts to find the mutual relationship among distributors, producers, consumers and the other prerequisite factors from the point of view in service environment and information quality in order to operate effectively the information perspective and system. Research design, data, and methodology - For the purpose of this study, the samples of consumers were targeted to Traceability System, and 661 people have been investigated. Through theoretical discussion of previous research, nine hypotheses were established, the influence of Continuous User Intention in TS. In order to test the hypotheses, a survey had conducted for 661 consumers as opinion leaders in their 20s-60s as data, and structural equation modeling was used. The difference analysis between Agricultural and Marine Products in TS; SPSS 22.0 and AMOS 22.0 were used for statistical analysis. Results - The major findings from this study were as follow; all factors of information quality excluding completeness and a social-impact had effects on the ease of use; all factors excluding understand ability in information quality and a social-impact had effects on the usefulness; completeness and social-impact had effects on perceived value; the ease of use had effects on usefulness and perceived value; usefulness had effects on perceived value and the intention of continuous use. From the results of different analysis, the CPLT(Completeness) factor has positive effects on Easy of USE and PV(Perceived Value) strongly in agricultural products. On the other hand, Social Duty has positive effects on Easy of Use strongly in marine products. Conclusion - In the age of information overflowing, TS will be a burden for users if it places too much emphasis upon accessibility. To accept and diffuse TS safely, therefore, Information System should be settled first into initial market formation. In addition, if TS elements are considered in conjunction with information factors and user environment, the acceptance and diffusion of TS would make synergy effect, even better. That is, this study contributes to the acceptance and diffusion of Traceability System. Accordingly, information quality will be settled into initial market formation. Also, social-impact element will be considered in conjunction with information quality's factors, and it will make synergy effect.

• Journal of Korean Academy of Nursing
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• v.11 no.2
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• pp.5-8
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• 1981

This study concerns itself with the development of a new model of comprehensive health service for rural communities of Korea. The study was conceived to resolve the problems of both underservice in rural communities and underutilization of valuable health manpower, namely the nurses, the disenchanted elite health personnel in Korea. On review of the current situation, the greatest deficiencies in the Korean health care system were found in the availability of primary care at the peripheries of md communities, in the dissemination of knowledge of disease prevention and health care, and in the induction of and guidance for active participation by the clientele in health maintenance at the personal, family and community level Abundant untapped health resources were identified that could be brough to bear upon the national effort to extend health services to every member of the Korean Population. Therefore, it was Postulated that the problem of underservice in rural communities of Korea can be structurcturally resolved by the effective mobilization and organization of untapped health resources, and that. a primary care Nursing Service System offers the best possibility for fulfillment of rural health service goals within the current health man-power situation. In order to identify appropriate strategies to combat the present difficulties in Korean rural health services and to utilize nurses and other health personnel in community-centered health programs, a search was made for examples of innovative service models throughout the world. An extensive literature survey and field visits to project sites both in Korea and in the United States were made. Experts in the field of world health, health service, planners, administrators, and medical and nursing practitioners in Korea, in the United States as well as visitors from other Asian countries were widely consulted. On the basis of information and inputs from these experts a new rural health service model has been constructed within the conceptual framework of community development, especially of the innovation diffusion Model. It is considered especially important that citizens in each community develop capacities for self-care with assistance and supports from available health professionals and participate in health service-related decisions that affect their own well-being. The proposed model is based upon the regionalization of health care planning utilizing a comprehensive Nursing Service System at the immediate delivery level The model features: (1) a health administration unit at each administrative level; (2) mechanisms for community participation; (3) a continuous source of primary health care at the local community level; (4) relative centralization of specialty care and provision of tertiary or super-specialty care only at major national metropolitan centers; and (5) a system for patient referral to the appropriate level of care. This model has been built around professional nurses as the key community health workers because their training is particularly suited and because large numbers of well-trained nurses are currently available and being trained. The special element in this model is a professional nurse-guided, self-care facilitating primary care Community Nursing Service System. This is supported by a Nursing Extension Service as a new training and support structure. (See attached diagrams). A broad spectrum of programs was proposed for the Community Nursing Service System. These were designed to establish a balance of activities between the clinic-centered individual care component and the field activity-centered educational and supportive component of health care services. Examples of possible program alternatives and proposed guidelines for health care in specific situations were presented, as well as the roles and functions of the key health personnel within the Community Nursing Service System. This Rural Health Service Model was proposed as a real alternative to the maldistributed, inequitable, uncoordinated solo-practice, physician-centered fee-for-service health care available to Koreans today.

• The Journal of the Petrological Society of Korea
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• v.9 no.4
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• pp.211-237
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• 2000

Major element zoning has been analyzed in garnet porphroblasts obtained from the Grt-St and Ky-Grt-St grade assemblages in Zones I on the northern flank of the Pelham Dome, north central Massachusetts. These porphyroblasts grew during multiple phases of deformation and meta-morphism revealed by the inclusion trail geometry plus the chemical zoning patterns within garnet porphyroblasts. Unusual zoning patterns, including zoning reversals and gradient changes in XMn, zlgzag patterns in Fe/(Fe +Mg) and staircase-shaped patterns in XCa, are coincident with textural truncations and other changes in microstructure within the garnet porphrublasts. Chemical variations in plagioclase, biotite, muscovite and staurolite combined with inclusion trail geometry and petrography reveal that the garnet zoning patterns are modified by combinations of the following. (1) Uni-and divariant reactions involving garnet consumption(Grt+ Chl+Ms=St+Bt+Qtz + $H_2$O) and production(St+Ms + Qtz= Bt+ Grt +A1$_2$$SiO_{5}$ + $H_2$O). (2) Deformation induced episudic ionit dissolution, preferential diffusion and re-distribution during foliation development. (3) P-T changes during growth of the porphyroblasts. The P-T paths combined with petrographic and inclusion trail morphology observations consist of two pattens; (1) heating/compression during NW-SE shortening; and (2) decompression with cooling during NNW-SSE shortening. Based on temperature-time(T-t) geochronological data and late-Paleozoic tectonic model, Alleghanian metamorphism, which is the result of heterogeneous shearing concentrated along the boundary between the Abalone Terrane(Pelham dome) and cover rocks(Bronson Hill Terrane), has produced Ky-St-Ms mineral assemblage during Pennsylvanian(290-300 Ma) in Shutesbury area. However, temperature of alleghanian metamorphism was not high enough to form garnet and staurolite in the Northfiled syncline area. Alleghanian metamorphism has affected only the matrix due to heterogeneous shearing in the study area.