• Journal of the Korean Society for Heat Treatment
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• v.31 no.2
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• pp.63-67
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• 2018

Recent mold industry uses many roll-to-roll processes that can produce high production speed and precision machining and automation process. In the circular cylinder mold, however, patterns of less than $10{\mu}m$ are difficult to manufacture and maintain. In this study, we fabricated a circular cylindrical mold with a DLC thin film which have high hardness, low coefficient of friction and high releasability by using lithography and lift-off process. The height, line width, and pitch of the fabricated DLC macro pattern are $3.1{\mu}m$, $9.1{\mu}m$ and $20.2{\mu}m$, respectively. The pattern size is finer than the current applied to the aluminum cylinder type, and this shows the possibility of practical use of DLC micro pattern roll mold.

• Nuclear Engineering and Technology
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• v.25 no.2
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• pp.193-203
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• 1993

A new heuristic method for loading pattern search has been developed to overcome short-comings of the algorithmic approach. To reduce the size of vast solution space, general shuffling rules, a regionwise shuffling method, and a pattern grouping method were introduced. The entropy theory was applied to classify possible loading patterns into groups with similarity between them. The pattern search program was implemented with use of the PROLOG language. A two-group nodal code MEDIUM-2D was used for analysis of power distribution in the core. The above mentioned methodology has been tested to show effectiveness in reducing of solution space down to a few hundred pattern groups. Burnable poison rods were then arranged in each pattern group in accordance with burnable poison distribution rules, which led to further reduction of the solution space to several scores of acceptable pattern groups. The method of maximizing cycle length(MCL) and minimizing power-peaking factor(MPF) were applied to search for specific useful loading patterns from the acceptable pattern groups. Thus, several specific loading patterns that have low power-peaking factor and large cycle length were successfully searched from the selected pattern groups.

• Design & Manufacturing
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• v.11 no.3
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• pp.1-7
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• 2017

The fabrication process of micro pattern structure with high precision and high aspect ratio using powder injection molding (PIM) is developed. In the PIM process, the metal powder is mixed with the binder systems and the mixture is injected into the metal mold. The injection molded green parts are debinded and sintered to reach final shape and properties. In this method, the optimization of physical properties such as fluidity and strength of the binder system is essential for perfect filling the high aspect ratio micro-pattern. For this purpose, the correlation between the properties of the binder system and feedstock and ${\mu}-PIM$ process was investigated, and a binder system with low viscosity at low temperature(about $110^{\circ}C$) and high strength after cooling was investigated and applied. Employing this process, high precision parts with line type micro pattern structure which has pattern size $160{\mu}m$ and aspect ratio more than 2 can be manufactured.

• Journal of the Korean Society for Heat Treatment
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• v.36 no.3
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• pp.137-144
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• 2023

Micro electro mechanical systems (MEMS) and precision machines require excellent friction and wear characteristics to improve energy efficiency generated during sliding motion. In this study, DLC thin film with high hardness and low friction was deposited on STS304 substrate material by CVD method, and dot-shaped convex and concave micropatterns were fabricated by photolithography process. The diameter of the pattern was 20 ㎛, the pitch was 40 ㎛, and a pattern having a mesh type arrangement was fabricated and an abrasion test was performed. The results of the wear test on the micro pattern confirmed that the friction coefficient characteristics were improved compared to STS 304 and DLC thin films. In addition, in this result, the micro-pattern showed 11.4% more improved friction coefficient than the DLC thin film. The friction coefficient characteristics for convex and concave patterns of the same size showed almost similar results.

• Journal of Korean Society of Forest Science
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• v.96 no.2
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• pp.227-234
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• 2007

The forest canopy gap has been well known as a substantial process of forest cyclic regeneration and important role in stand structure, dynamics, and biodiversity of the forest ecosystem. Based on 3,600 $5m{\times}5m$ square grids in a 9ha permanent experimental plot, the study was conducted to evaluate the regeneration pattern of woody species by developmental stage {seedlings (<1 m of height), saplingI (>1 m of height, <2 cm of DBH), and saplingII (2 cm$<200m^2$), $201-400m^2$, $400-600m^2$, $601-800m^2$, and $>800m^2$) in the mixed broadleaved-Korean pine forest. The results indicated that the regenerating trees of Populus ussuriensis occurred only in the canopy gap area, considered to be a typical gap-dependent species. The regeneration of Ulmus japonica, Ulmus laciniata, and Maackia amurensis could be generally satisfied with the gap size of $201-600m^2$, Betula costata and Prunus padus with gap size of $401-800m^2$, Picea koraiensis with gap size of $201-800m^2$, Fraxinus mandshurica and Syringa reticulata var. mandshurica with smaller than $800m^2$, respectively. Acer ukurunduense and Acer tegmentosum were likely to have no problem with the gap size to make gap regeneration. Acer mono and Tilia amurensis looked more capable of regenerating in the closed canopy disregarding the upper crown condition. The regeneration of Pinus koraiensis and Abies nephrolepis had no trouble under the canopy condition in less than $800m^2$of gap size. The density of regenerating shrubs was rather high, especially under the closed canopy, considered to be associated with great amount of regeneration production in such shade tolerant species as Lonicera maackii, Corylus mandshurica, Euonymus pauciflorus, and Philadelphus schrenkii under the closed canopy. Pearson correlation coefficient was computed to compare the similarity among non-gap area and five gap size classes by developmental stages for trees and shrubs. The similarity coefficients among closed canopy and the gap size classes were mostly significantly correlated to each other with a few exceptions.

• Journal of the Korea Fashion and Costume Design Association
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• v.17 no.2
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• pp.155-172
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• 2015

This study analyzed the change pattern of Korean male body size in their 40s-60s and their current body shape based on the research materials of the 5th(2004) and 6th(2010) conducted by Size Korea. The purposes of this study are to make the related fashion industry recognize the changes of Korean male body size in their 40s-60s and suggest basic materials for clothing design that reflects such trend. As a result of analyzing changes of male body size in their 40s-60s by age, it was found that height, length, breadth and weight decreased across most of the items as the age increased. As for circumference, as the age increased, waist circumference (natural indentation), waist circumference (omphalion), and abdominal extension circumference increased, while other items decreased. In relation to the depth, as the age increased, hip depth and armscye depth decreased, while chest depth, bust depth, waist depth (natural indentation), and waist depth (omphalion) increased. Analyzing the change pattern of Korean male body size in their 40s-60s according to measurement year, height size increased in the 6th year across most of the body part items compared to the 5th year. It means that height of body parts related to body height increased in overall. As for circumference, most items showed decrease, which means that Korean male's body shape in their 40s-60s gets slim gradually. While the breadth of the chest decreased, the depth of the chest increased. which is assumed due to the increase in exercise according to high interest in health in a society. It will be possible to design proper clothes for consumer body type and trends if we design clothes that afford multilateral attention to the patterns, design, or material in clothing design by applying the aspects of Korean male body size in their 40s-60s and body type change.

• Tunnel and Underground Space
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• v.20 no.5
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• pp.325-331
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• 2010

In the present research paper large scale blasting was conducted on two different firing patterns, namely, straight V type and skewed V type pattern on the same sandstone overburden bench with similar explosives. The post-blast fragmentation assessments were made by use of digital imaging technique. The total cycle time of 10 $m^3$ rope shovels was also recorded in the field. The results reveal improvements in the fragmentation and excavator performance results for the blasts fired on skewed V type pattern. The paper discusses the skewed V firing pattern and the reasons for its superior performance vis-$\grave{a}$-vis the straight V type pattern.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.12
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• pp.1150-1154
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• 2003

The voltage profile during discharge of the zinc air battery has very flat pattern until reach to end of discharge voltage. But, when zinc air battery is discharged by high current, the discharge voltage and energy becomes low. Therefore, we focused on effects of catalyst size to solve this problems by increasing active sites of oxygen reduction reaction. The size of catalyst was reduced from 27 to l${\mu}{\textrm}{m}$ and we examined average discharge voltage, capacity, energy, resistance and characteristics during GSM pulse discharge of zinc air battery with change of current density. And we also measured porosity of the cathode according to the ASTM. So we have got improvement of average discharge voltage and energy when catalyst was minimized and we have got optimum size of catalyst at 5${\mu}{\textrm}{m}$.

• Preventive Nutrition and Food Science
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• v.3 no.3
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• pp.292-294
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• 1998

Surimi sol and gel were prepared by mixing egg albumin, starch, oil and carrageenan, which are used as representative ingredients in the surimi composite, at different ratio. Structural properties in surimi composite were investigated by examining the phase changes and dispersion pattern (average particle size, size range and the averge number of particle) of the particulate ingredients in sol and gel with an image analyzer. A staining technique of the specimen containing egg albumin in surimi gel was developed by adjusting pH of a toluidine staining solution. Image analysis revealed that size and density of ingredient particles were function of the level and dispersion of ingredients except of starch-incorporated surimi gel which showed maximum particle size at 6%.

• Journal of the Korean Society of Clothing and Textiles
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• v.41 no.4
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• pp.752-770
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• 2017

This study provides a size specification and ease for the development of pants for working clothes in the construction industry according to season. We collected and measured the size specification of 4 types of Spring/Fall pants, 4 types of winter brushed bonding pants, and 4 types of winter padded pants. Subjective comfort evaluation and analysis of ease sensation were performed for all products on 12 subjects. The average size specifications for the pants according to seasons were as follows. Spring/Fall pants had 74.0/80.0cm waist size (relaxed/maximum stretched) and 104.0cm hip size. Winter brushed bonding pants had 76.0/83.4cm for waist size and 106.0cm for hip size. Winter padded pants had 71.5/84.0cm for waist size and 112.8cm for hip size. When designing a pattern by comparing product size specification and subject body size, the recommended ease is 0.2/7.2cm for waist size (relaxed, maximum stretched) and 13.6cm for hip size for Spring/Fall pants, and 0.2/6.2cm for waist size and 11.6cm for hip size of winter brushed bonding pants, and -5.3/7.2cm for waist size and 19.4cm for the hip size of winter padded pants.