• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.777-781
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• 1997

In this study, the effect of strain-rate and inital solid fraction on the deformation behaviour of semi-solid material is investigated, when semi-solid forging is performed by the process of closed-die compression using A356 alloy of which the above results can be practically applied for industrical purpose. In order to simulate densification in the deformation of semi-solid material, the semi-solid material is assumed to be composed of solid region following rigid visco-plastic material, the liquid region following Darcy's law for the liquid flow saturated in the interstitial space. Simulation results of closed-die compression and simple upsetting under different strain-rate and initial solid fraction are compared.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1997년도 춘계학술대회논문집
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• pp.98-105
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• 1997

The behaviour of alloys in the semi-solid state strongly depends on the imposed stress state and on the morphology of the phase which can very from dendritic to globular. The estimation of behaviour characteristic in the compression simulation with seim-solid materials are calculated by finite element method with proposed algorithm. The proposed theoretical model and a various boundary conditions for compression process is investigated with the coupling calculation between the liquid phase flow and the solid phase deformation. The simulation process considering soldification phenomena is performed to the isothermal conditions of two dimensional problems. To analysis of compression process by using semi-solid materials, a new stress-strain relationship is described, and compression analysis is performed by viscoelastic model for the solid phase and the Darcy's law for the liquid flow. The calculated results for compression force and ram displacement will be compared to experimental data.

• 소성∙가공
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• 제6권4호
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• pp.338-345
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• 1997

The behaviour of alloys in the semi-solid state strongly depends on the imposed stress stage and on the morphology of the phase which can vary from dendritic to globular. To optimal net shape forging of semi-solid materials, it is important to investigate for material behaviour for variation of strain rate. Therefore, to investigate the effect of compression speed on deformation of aluminum alloy with globular microstructure, the compression test for semi-solid aluminum alloy with controlled solid fraction is perform by material test system which is attracted with furance. The behavior of semi-solid aluminum alloy were discussed for the various solid fraction and die speed. The material constants in stress-strain were are also proposed.

• 산업공학
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• 제16권spc호
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• pp.87-92
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• 2003

Progressive mesh representation and generation have become one of the most important issues in network-based computer graphics. However, current researches are mostly focused on triangular mesh models. On the other hand, solid models are widely used in industry and are applied to advanced applications such as product design and virtual assembly. Moreover, as the demand to share and transmit these solid models over the network is emerging, the generation and the transmission of progressive solid models depending on specific engineering needs and purpose are essential. In this paper, we present a Cellular Topology-based approach to generating and transmitting progressive solid models from a feature-based solid model for internet-based design and collaboration. The proposed approach introduces a new scheme for storing and transmitting solid models over the network. The Cellular Topology (CT) approach makes it possible to effectively generate progressive solid models and to efficiently transmit the models over the network with compact model size.

• Korean Chemical Engineering Research
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• 제53권4호
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• pp.440-444
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• 2015

Effects of operating variables on the solid circulation rate were investigated in a three-phase circulating fluidized bed, of which inside diameter was 0.102m and height was 3.5m, respectively. Gas velocity, primary and secondary liquid velocities, particle size and height of solid particles piled up in the solid recycle device were chosen as operating variables. The solid circulation rate increased with increasing primary and secondary liquid velocities and height of solid particles piled up in the solid recycle device, but decreased with increasing particle size. The value of solid circulation rate decreased only slightly with increasing gas velocity in the riser. The values of solid circulation rate were well correlated in terms of dimensionless groups within the experimental conditions.

• 한국정밀공학회지
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• 제13권3호
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• pp.150-157
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• 1996

In this paper, to develop a smart CAD/CAM system for systematically performing from the 3-D solid shape design of products to the CNC cutting operation of products by a machining center, a B-Rep solid modeler is realized based on the half edge data structure. Because the B-Rep solid modeler has the various capabilities related to the solid definition functions such as the creation operation of primitives and the translational and rotational sweep operation, the solid manipulation functions such as the split operation and the Boolean set operation, and the solid inversion function for effectively using the data structure, the 3-D solid shape of products can be easily designed and constructed. Also, besides the automatic generation of CNC code, the B-Rep solid modeler can be used as a powerful tool for realizing the automatic generation of finite elements, the interfer- ence check between solids, the structural design of machine tools and robots and so on.

• 한국주조공학회지
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• 제16권6호
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• pp.565-575
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• 1996

In this study, to gain the semi-solid alloy we employed the electromagnetic rotation by a induction motor of 3-phases and 2-poles for Al-7wt%Si alloy and observed the size of primary solid particle, distribution state of primary solid particle, the degree of sphericity, and fraction of primary solid for the evaluation of its results. The size of primary solid particle increases from $98{\mu}m$ to $118{\mu}m$ as solid fraction increases from 0.2 to 0.5. The degree of sphericity increased as the solid fraction increased. Solid particles obtained from the microstructures of isothermally held sample were coarsened and the degree of sphericity was enhanced as isothermal holding time increased. However, when the sample was stirred for more than 40min, solid particles merged together and liquid phase was entrapped within the cluster of solid particles. The size of primary solid particle was not changed significantly with the variation of input voltages by 160V over which solid particles began to merge together to be a large cluster of about $170{\mu}m$ at 180V. The standard deviation and the degree of sphericity were not changed significantly with the variation of input voltage.

• Journal of Pharmaceutical Investigation
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• 제37권1호
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• pp.1-5
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• 2007

Solid dispersions of piroxicam were prepared by melting method using poloxamer as a carrier. The results of DSC and XRD studies showed that the amorphous farm of piroxicam coexisted with the crystalline form in the solid dispersions. However, the ratio of crystalline form of piroxicam in the solid dispersion prepared by melting method decreased in comparison with the same ratio of the solid dispersion prepared by solvent method. As the ratio of poloxamer in the solid dispersion increased, the ratio of the amorphous form of piroxicam in the solid dispersion increased. The dissolution rate of piroxicam from the solid dispersions was significantly higher than that from piroxicam powder. In comparison to the solid dispersion prepared by solvent method, the dissolution rate of piroxicam from the solid dispersion prepared by melting method was higher. As the ratio of poloxamer in the solid dispersion prepared by melting method increased, the initial dissolution rate decreased, however, the total amount dissolved at the end of the study increased.

• 한국분말재료학회지
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• 제31권4호
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• pp.293-301
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• 2024

All-solid-state lithium batteries (ASSLBs) are receiving attention as a prospective next-generation secondary battery technology that can reduce the risk of commercial lithium-ion batteries by replacing flammable organic liquid electrolytes with non-flammable solid electrolytes. The practical application of ASSLBs requires developing robust solid electrolytes that possess ionic conductivity at room temperature on a par with that of organic liquids. These solid electrolytes must also be thermally and chemically stable, as well as compatible with electrode materials. Inorganic solid electrolytes, including oxide and sulfide-based compounds, are being studied as promising future candidates for ASSLBs due to their higher ionic conductivity and thermal stability than polymer electrolytes. Here, we present the challenges currently facing the development of oxide and sulfide-based solid electrolytes, as well as the research efforts underway aiming to resolve these challenges.

• Korean Chemical Engineering Research
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• 제47권2호
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• pp.195-202
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• 2009

선택적 고체순환이 가능한 2탑 유동층 공정 개발을 위한 기초연구로 금속 망이 장착된 입자크기분리 시스템에 의해 입자크기 차이를 이용하여 고운입자와 굵은입자를 분리할 수 있는 고체분리기를 개발하였으며 고체분리속도에 미치는 유속, 고체분리기의 설치높이 및 분리면적의 영향을 측정 및 고찰하였다. 고체분리기에 의한 고체분리속도는 기체유속, 고체분리기의 설치높이, 분리면적이 증가함에 따라 증가하였다. 기체유속 및 고체분리기 설치높이 증가에 따른 고체분리속도의 변화경향은 기포크기의 변화경향과 유사하였다. 본 연구에서 개발한 고체분리기를 이용하여 굵은입자($212{\sim}300{\mu}m$)와 고운입자($63{\sim}106{\mu}m$)의 분리가 가능하였으며 고체분리속도는 4.4~127 g/min의 범위를 나타내었다. 개발된 고체분리기를 회수증진 수성가스변환 공정에 적용하여 선택적 고체순환이 가능한 2탑 유동층 공정구성을 제안하였다.