• Toxicological Research
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• 제35권3호
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• pp.287-294
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• 2019

The possibility of eye exposure for workers participating in manufacturing of nanoparticles or consumers using products containing nanoparticles has been reported, but toxicity studies on the eye are scarce. In this study, cytotoxicity of five nanoparticles including silver, ceria, silica, titanium and zinc were tested using Statens Seruminstitut Rabbit Cornea (SIRC) cells. When cells were treated with nanoparticles with concentrations of $1-100{\mu}g/mL$ for 24 hr, zinc oxide nanoparticles showed higher toxicity to cornea cells. $LC_{50}$ of zinc oxide nanoparticles was less than $25{\mu}g/mL$ but those of other nanoparticles could not be calculated in this test, which means more than $100{\mu}g/mL$. Generation of reactive oxygen species was observed, and expression of apoptosis related biomarkers including Bax and Bcl-2 were changed after treatment of zinc oxide nanoparticles, while no other significant toxicity-related changes were observed in cornea cells treated with Ag, $CeO_2$, $SiO_2$ and $TiO_2$ nanoparticles.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1245-1248
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• 1996

This paper describes a cell programming environment that deals with problems associated with programming Flexible Manufacturing Cells(FMCs). The environment consists of the cell programming editor and the automatic generation module. In the cell programming editor, cell programmers can develop cell programs using task level description set which supports task-oriented specifications for manipulation cell activities. This approach to cell programming reduces the amount of details that cell programmers need to consider and allows them to concentrate on the most important aspects of the task at hand. The automatic generation module is used to transform task specifications into executable programs used by cell constituents. This module is based on efficient algorithm and expert systems which can be used for optimal path planning of robot operations and optimal machining parameters of machine tool operations. The development tool in designing the environment is an object-oriented approach which provides a simple to use and intuitive user interface, and allows for an easy development of object models associated with the environment.

• 한국기계가공학회지
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• 제13권3호
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• pp.70-76
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• 2014

The intensity of sunlight becomes lower when weather conditions change, which affects whether a solar-electric vehicle can be driven on a shady road. The power delivered by solar cells can be vary depending on the amount of shade. As a result, the battery system is often used to compensate for variations in the power delivered by solar cells. Therefore, studies of power control systems for solar-electric vehicles are required. In this paper, mathematical models for such a power control system are studied and important variables are considered. Simulation and test results show that the mathematical model and actual designs developed here would be effective when used with solar-electric vehicles.

• 산업경영시스템학회지
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• 제22권53호
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• pp.89-97
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• 1999

We are concerned with the optimal design of flexible manufacturing cells in this study, thus try to suggest the detail information for each resource on the optimal conditions. Object oriented simulation technology is used to write models more easily and to execute simulation running time more rapidly, and the optimal level of relevant decision variables is probed by response surface methodology(RSM), which is well known for the optimization technology based on experiment design and regression equation. We investigate the optimal level for the number of pallets and the speed of AGVs of FMC systems, carry out the performance analysis of this system. Consequently we suggest systematic procedures for the optimization of FMCs in detail design stage.

• 한국국방경영분석학회지
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• 제27권2호
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• pp.25-36
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• 2001

In this paper a new heuristic algorithm has been developed and presented for logistics for multiple objectives in an automated manufacturing systems. We proposed Simallest Processing and Average setup time Ratio First(SPARF) algorithm for multiple criteria under sequence setup time. The heuristic algorithm is implemented on the various problem cases by number of jobs and machines. The proposed algorithm provided smaller than the previously documented heuristics. The results obtained show a superior solution by the new heuristic over previous heuristics on all problem sizes. we perform analyses of variance to fortify the above results of comparison with the previous algorithms to the four cases using Statistical Analysis System(SAS) package. The results show that the larger is the number of groups or cells, the bigger is the amount of improvement by the proposed algorithms. It suggests that the algorithms proposed is strongly influenced by the number of cells, groups and interaction of these factors.

• 한국기계가공학회지
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• 제19권10호
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• pp.8-15
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• 2020

The diffusion cell method is the main technique employed for the in vitro diffusion test of transdermal drug delivery preparations. Most existing transdermal diffusion devices use a water bath heating structure and direct current motor magnetic stirrer. However, these devices are confronted with problems, such as large volume, incompatible vertical and horizontal diffusion cells, few diffusion cell sets, and poor reliability. To overcome these deficiencies, the system adopts a dry heating method and uses a rotating magnetic field generated by the electromagnetic stirrer to drive the magnetic stirrer. Accordingly, the resulting device is characterized by a simple structure and small volume, convenient operation, compatible vertical and horizontal diffusion cells, and numerous diffusion cell sets. The reliability and practicability of the system is verified by the in vitro percutaneous permeability test of the bisoprolol patch.

• Carbon letters
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• 제16권3호
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• pp.135-146
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• 2015

Graphite can be classified into natural graphite from mines and artificial graphite. Due to its outstanding properties such as light weight, thermal resistance, electrical conductivity, thermal conductivity, chemical stability, and high-temperature strength, artificial graphite is used across various industries in powder form and bulk form. Artificial graphite of powder form is usually used as anode materials for secondary cells, while artificial graphite of bulk form is used in steelmaking electrode bars, nuclear reactor moderators, silicon ingots for semiconductors, and manufacturing equipment. This study defines artificial graphite as bulk graphite, and provides an overview of bulk graphite manufacturing, including isotropic and anisotropic materials, molding methods, and heat treatment.

• International Journal of Precision Engineering and Manufacturing
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• 제1권2호
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• pp.124-131
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• 2000

A shop floor can be considered as and importand level to develop a Computer Integrated Manufacturing system (CIMs). The shop foor is a dynamic environment where unexpected events contrinuously occur, and impose changes to planned activities. The shop floor should adopt an appropriate control system that is responsible for scheduling coordination and moving the manufacturing material and information flow. In this paper, the architecture of the hybrid control model identifies three levels; i.e., the shop floor controller (SFC), the cell controller(CC) and the equipment controller (EC). The methodology for developing these controller is employ an object-oriented approach for static models and IDEF0 for function models for dispatching a job. SFC and CC are coordinated by employing a multi-factors bidding and an adapted Analytic Hierarchy Process(AHP) prove applicability of the suggested method. Test experiment has been conducted by with the shopfloor, consisting of six manufacturing cells.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1409-1410
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• 2008

Layer manufacturing technology has been recently spotlighted as a promising candidate to fabricate porous scaffolds for tissue engineering, because it can provide three dimensional interconnectivity and different pore structures and on-demand scaffold design. This study aims to fabricate HA/PCL composite scaffolds for bone tissue engineering by a layer manufacturing technology, paste extruding deposition, and to characterize in vitro and in vivo biocompatibilities of the scaffolds. This study discusses the mechnical properties, proliferation and differentiation of osteogenic cells, and tissue in-growth and bone regeneration behavior using animal models.

• 한국CDE학회논문집
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• 제12권4호
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• pp.298-307
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• 2007

In recent years, researchers are actively investigating new methods that are applicable for manufacturing micrometer to nanometer scale structures. Among them, optical tweezers that can manipulate microscopic objects using a laser is receiving one of the key attentions. Optical tweezers have been used actively in the field of science. For example, for measuring mechanical characteristics in the scale of piconewtons or for manipulating and sorting large numbers of particles, bacteria, cells. etc. However, little works have been reported for "manufacturing" objects. In this paper, we present a new method for manufacturing micrometer scale structures using micrometer scale biotin coated polystyrene particles. Particles will be controlled with a user interface that utilizes a CyberGlove and glued together by the bonding force between biotin and streptavidin.