• Korean Journal of Computational Design and Engineering
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• v.20 no.2
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• pp.145-158
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• 2015

ISO 15926 is an international standard for the sharing and integration of plant lifecycle information. Plant design data consist of logical configuration, equipment specifications, 2D piping and instrument diagrams (P&IDs), and 3D plant models (shape data). Although 3D computer-aided design (CAD) data is very important data across the plant lifecycle, few studies on the exchange of 3D CAD data using ISO 15926 have been conducted so far. For this, we analyze information requirements regarding plant 3D design in the process industry. Based on the analysis, ISO 15926 templates are defined for the representation of constructive solid geometry (CSG) - based 3D design data. Since system environments for 3D CAD modeling and Semantic Web technologies are different from each other, we present system architecture for processing and visualizing plant 3D design data in the Web Ontology Language (OWL) format. Through the visualization test of ISO 15926-based 3D design data for equipment with a prototype system, feasibility of the proposed method is verified.

• Korean Journal of Computational Design and Engineering
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• v.12 no.2
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• pp.101-108
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• 2007

As 3D solid modeling has been widely used in designing products, solid models of the products are directly used in various applications such as engineering analysis and process planing. However, the fully-detailed solid models may not be necessary in some application. For example, it is often more efficient to use simplified model of part of engineering analysis. Generation of mesh for the complex original model requires a quite amount of time, and the consequence of finite element analysis may not be desirable due to small and detailed geometry in the model. In this paper, a method to simplify solid models of machined part is presented. This method decomposes the delta volume of machined part, and uses the decomposed volumes to simplify the solid model. Since this method directly recognizes the features to be removed from the final model, it is independent of not only design features of specific CAD system, but also designer's design practice of design sequences.

• The Microorganisms and Industry
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• v.18 no.1
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• pp.2-8
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• 1992

The present study was undertaken to characterize the biodegradation of phenoxy herbicides, 2,4-D and MCPP, under aerobic conditions. Specifically, the work had the following objectives; i) to develop and characterize bacterial mixed cultures for the 2,4-D and MCPP degradation, ii) to evaluate the degradation of 2,4-D and MCPP in shake-flasks and stirred tank reactors; and iii) to evaluate the treatment of industrial fertilizer solid wste material containing 2,4-D and MCPP.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.169-170
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• 2013

• Journal of Pharmaceutical Investigation
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• v.27 no.4
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• pp.295-301
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• 1997

Nitrendipine, a slightly soluble calcium channel blocking agent forms a solid dispersion system with $hydroxypropyl-{\beta}-cyclodextrin$, which exhibits better dissolution characteristics than the uncomplexed drug. The dissolution rate of nitrendipine was markedly increased in solid dispersion system in pharmacopeial disintegration media at pH 1.2 and pH 6.8. Four different dosage forms of nitrendipine were administered to rats: (a) nitrendipine in the solution of PEG 400; (b) nitrendipine solid dispersion system with $hydroxypropyl-{\beta}-cyclodextrin$ in a molar ratio of 1:2 by solvent evaporation method and administered in capsule form; (c) physical mixture of nitrendipine with $hydroxypropyl-{\beta}-cyclodextrin$ in a molar ratio of 1:2 and administered in capsule form; (d) nitrendipine alone administered in capsule form. Relative bioavailability after the oral administration of various dosage forms to rats with a dose of 10 mg/kg equivalent to nitrendipine was compared with that of nitrendipine in the solution of PEG 400. The AUC of solid dispersion was significantly bigger than that of nitrendipine powder. $T_{max}$ of solid dispersion was significantly shorter and $C_{max}$ was higher than that of nitrendipine powder. These results indicate that the bioavailability of nitrendipine could be improved markedly by inclusion complexation. An interesting correlation also appears to exist between the in vitro dissolution data and the area under the plasma concentration-time curves.

• Tribology and Lubricants
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• v.25 no.1
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• pp.61-65
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• 2009

Tribological properties of the semi-metallic friction materials containing different solid lubricants (graphite, $WS_2$, $MoS_2$) were investigated. The friction materials were fabricated with an experimental formulation and tested with gray cast iron disks. Results showed that graphite contributed to stabilize the friction coefficient during run-in processes. Also, graphite provided better fade resistance than that of $WS_2$ and $MoS_2$. At intermediate temperature ranges, however, friction materials with $WS_2$ or $MoS_2$ maintained higher friction effectiveness than that of graphite. On the other hand, friction materials containing $MoS_2$ showed increased wear rates than that with graphite or $WS_2$. Friction materials with proper combinations of two solid lubricants showed better friction and wear properties than that of the friction materials containing single solid lubricant.

• Proceedings of the KIEE Conference
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• 2000.11c
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• pp.425-427
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• 2000

We describe the preparation of a cobalt oxide in which the solid-pore architecture of the material is controllably varied. All $CoO_2$ gels derived from $CoCl_2$-based sol-gel synthesis, but exhibit markedly different final pore structures based on how the pore fluid is removed from forces that result from extraction are either low or nonexistent. These nanoscale mesoporous materials have higher $CoO_2$ crystallites. Controlling both the pore and solid architecture on the nanoscale offers a strategy for the design of new supercapacitor and charge-storage materials.

• Structural Engineering and Mechanics
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• v.76 no.3
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• pp.379-393
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• 2020

In this paper, we propose an automatic procedure to improve the accuracy of finite element solutions using enriched 2D solid finite elements (4-node quadrilateral and 3-node triangular elements). The enriched elements can improve solution accuracy without mesh refinement by adding cover functions to the displacement interpolation of the standard elements. The enrichment scheme is more effective when used adaptively for areas with insufficient accuracy rather than the entire model. For given meshes, an error for each node is estimated, and then proper degrees of cover functions are applied to the selected nodes. A new error estimation method and cover function selection scheme are devised for the proposed adaptive enrichment scheme. Herein, we demonstrate the proposed enrichment scheme through several 2D problems.

• Electrical & Electronic Materials
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• v.16 no.1
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• pp.60.2-60
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• 2003

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.91-96
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• 2005

In this paper, describes the design and performance of a 1.5 kW solid-state pulsed power amplifier, operating over 2.7-2.9 GHz at a duty of 10% and with a pulse width of 100 us for radar application. The solid-state pulsed power amplifier configures a series of 8-stage cascaded power amplifier with different RF output power levels. Low loss Wilkinson combiners are used to combine output powers of six 300W high power solid state modules. Tests show peak output power of 1.61 kW, corresponding to PAE of 26.2% over 2.7-2.9 GHz with pulse width of 100 us and a PRF of 1 kHz.