• Transactions of the Korean Society of Automotive Engineers
• /
• v.24 no.4
• /
• pp.416-424
• /
• 2016

A robust design of head gasket is pursued by using FEA model of engine assembly. Engine assembly model consists of cylinder head, block, gasket, and head bolt is constructed to understand a complex behavior of this engine compound. Thermal loading is performed on the assembled engine cylinder and block to obtain temperature field. Firing load is added to the results of heat transfer analysis to simulate the engine operation condition. Temperature filed results from heat transfer analysis are mapped into the structural mesh. Contact pressure distribution along the bead has been monitored for the engine operation condition. Based on the results obtained from the analysis, Taguchi method has been adopted for a robust design process of head gasket. Among the control factors, bolt size affects most robustness of head gasket sealing.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2022.10a
• /
• pp.237-237
• /
• 2022

Cynodon transvaalensis belongs to the warm-season grasses and is one of the economically and ecologically important crops. Cynodon species with high heterozygosity are difficult to assemble, so genome research has not been actively conducted. In this study, hybrid assembly was performed by sequencing with Illumina and PacBio. As a result of the assembly, the number of scaffolds and the length of N50 were 1,392, 928 kb, respectively. The completeness of the assembly was confirmed by BSUCO at 98.3%. In addition, as a result of estimating the size of the assembled genome by K-mer analysis (k=25), it was approximately ~413 Mb. A total of 37,060 cds sequences were annotated in the assembled genome, and their functions were identified through blast. After that, we try to complete the assembled genome into a pseudochromosome-level genome through Hi-C technology. These results will not only help to understand the complex genome composition of african bermudagrass, but also provide a resource for genomic and evolutionary studies of grass and other plant species.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.21 no.2
• /
• pp.79-86
• /
• 2022

Numerous fabrication techniques have been used to mimic cylindrical natural tissues, such as blood vessels, tendons, ligaments, and skeletal muscles. However, most processes have limitations in achieving the biomimetic properties of multilayered and porous architectures. In this study, to embrace both features, a novel self-assembly method was proposed using electrospun microfibrous sheets. A bilayer microfibrous structure, comprising two sheets with different internal stresses, was fabricated by electrospinning a polycaprolactone (PCL) sheet on a uniaxially stretched thermoplastic polyurethane (TPU) sheet. Then, by removing the stretching tension, the sheet was rolled into a hollow cylindrical structure with a specific internal diameter. The internal diameter could be quantitatively controlled by adjusting the thickness of the PCL sheet against that of the TPU sheet. Through this self-assembly method, biomimetic cylindrical structures with multilayer and porous features can be manufactured in a stable and controllable manner. Therefore, the resulting structures may be applied to various tissue engineering scaffolds, especially vascular and connective tissues.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.11
• /
• pp.4027-4034
• /
• 2011

$CaCO_3$ crystalline structures having novel assemblies were in situ fabricated as analogs of naturally occurring proteins and polysaccharides for biomineralization. The calcite crystal was mineralized in a poly(vinyl alcohol)-$Ca^{2+}$ complex film immersed in a $Na_2CO_3$ solution containing poly(aspartic acid). The morphology and size of the $CaCO_3$ crystals were tuned by varying the concentration of poly(aspartic acid). The mechanisms of their nucleation orientation and formation were investigated experimentally and through molecular dynamics (MD) simulations in order to obtain a better understanding of the interactions between the polymers and the crystal at the molecular level. Both the MD results and experimental results indicate that the interaction between PVA and calcite mainly depends on the concentration of the polymer. The novel approach proposed herein for the fabrication of inorganic crystalline assembly structures can be used to fabricate precise crystalline structures.

• Health Policy and Management
• /
• v.26 no.4
• /
• pp.279-288
• /
• 2016

Graphic health warning on the tobacco product package is a cost-effective tobacco control policy to convey information on harmful effect of tobacco use to health, and it is known not only to motivate smokers to quit but also to deter adolescents from start smoking. In case of Korea, amendments to National Health Promotion Act requiring implementation of graphic health warning had been submitted 13 times, from 2002 to May 2015. In May 2015, the amendment had been approved by the National Assembly and it enters into force on December 23, 2016. This research analyzed the discussions from Health and Welfare Committee of the National Assembly during the implementation of the graphic health warning in order to study decision making process of legislators. Study found that there was a shift from a general opposition on implementing graphic health warning at first to a harsh conflict over relaxation of the regulation once discussing the implementation in earnest. Particularly, while the group supporting the implementation of the graphic health warning or opposing relaxation advocated the amendment with scientific and knowledge-based evidences including the World Health Organization Framework Convention on Tobacco Control, the group opposing the adoption of the amendment itself or suggesting relaxation tended to defend their position with empathy on smokers or tobacco industries.

• Carbon letters
• /
• v.27
• /
• pp.26-34
• /
• 2018

To formulate folate receptor (FR)-specific graphene-based electrochemical electrodes, a folic acid (FA) derivative attached with two pyrene molecules on the glutamate tail of FA was synthesized. The resulting pyrene-functionalized FA (FA-Py) presented the spontaneous noncovalent binding on chemically reduced graphene oxides (rGO) through an ${\pi}-{\pi}$ interaction. Ultrathin morphology, high water-resistance, and preservation of intact FR-specific pteroates from the rGO/FA-Py assembly allow this assembly to be exploited as robust and FR-specific electrochemical electrode materials. The limits of detecting rGO/FA-Py modified electrodes were found to be as low as 3.07 nM in FR concentrations in cyclic voltammetry analysis.

• The Korean Nurse
• /
• v.23 no.3 s.126
• /
• pp.32-41
• /
• 1984

• Proceedings of the KIEE Conference
• /
• 2003.07d
• /
• pp.2450-2452
• /
• 2003

We present a method to increase the productivity of multihead-gantry chip mounters for PCB assembly lines. To minimize the assembly time, we generate the mount sequence using the genetic algorithm. The chromosome, fitness function, and operators are newly defined to apply the algorithm. Simulation results are presented to verified the usefulness of the method.

• Journal of the Korea Society of Computer and Information
• /
• v.21 no.3
• /
• pp.57-64
• /
• 2016

This paper deals with the PCB assembly time minimization problem that the PAP (pick-and-placement) machine pickup the K-weighted group of N-components, loading, and place into the PCB placement location. This problem considers the rotational turret velocity according to component weight group and moving velocity of distance in two component placement locations in PCB. This paper suggest heavy-weight component group first pick-and-place strategy that the feeder sequence fit to the placement location Hamiltonean cycle sequence. This algorithm applies the quadratic assignment problem (QAP) that considers feeder sequence and location sequence, and the linear assignment problem (LAP) that considers only feeder sequence. The proposed algorithm shorten the assembly time than iATMA for QAP, and same result as iATMA that shorten the assembly time than ATMA.

• International Journal of Automotive Technology
• /
• v.7 no.2
• /
• pp.217-226
• /
• 2006

To maintain competitiveness in the modern automotive market, it is important to carry out process planning concurrently with new car development processes. Process planners need to make decisions concurrently and collaboratively in order to reduce manufacturing preparation time for developing a new car. Automated generation of a simulation model by using the integrated process plan database can reduce time consumed for carrying out a simulation and allow a consistent model to be used throughout. In this research, we developed a web-based system for concurrent and collaborative process planning and flow analysis for an automotive general assembly using web, database, and simulation technology. A single integrated database is designed to automatically generate simulation models from process plans without having to rework the data. This system enables process planners to evaluate their decisions quickly, considering various factors, and easily share their opinions with others. By using this collaborative system, time and cost put into the assembly process planning can be reduced and the reliability of the process plan would be improved.