• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.1
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• pp.83-88
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• 2016

Because of the increasing tool cost for cutting hard-to-cut materials, abrasive water jet (AWJ) milling recently has been regarded as a potential alternative machining method. However, it is difficult to control the depth and width of cut in AWJ milling because they vary depending on many AWJ cutting parameters. On 27 conditions within a limited range of pressure, feed rate, and abrasive flow rate, AWJ cutting was conducted on titanium, and depth profiles were measured with a laser sensor. From the depth profile data, depth and width of cut were acquired at each condition. The relationships between depth and parameters and between width and parameters were derived through regression analysis. The former can provide proper cutting conditions and the latter the proper pick feed necessary to generate a milled surface. It is verified that pressure mostly affects depth, whereas abrasive flow rate mostly affects width.

• Journal of the Korea Fashion and Costume Design Association
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• v.8 no.1
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• pp.69-79
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• 2006

The purpose of this study is to find the proper width of fabric which can bring high efficiency on productivity. We focus on the marking method by comparing and analyzing the marking efficiency of A-line skirt. This study employs 4 criteria to mark the A-line skirt, which are cutting method, angle, width, and direction, respectively. There can be 2 different cutting methods(fold pattern and add seam pattern at the front and back center line), and 2 different angles(warp angle and bias angle). Also, width of the fabric can be classified into 2 groups(110cm, 150cm), and marking direction can be grouped into 2(one direction marker and one direction per each size marker). These 4 criteria make 16($2^*2^*2^*2$) cases for this study. Main findings are follows. First, the skirt with folded at the center line had higher efficiency rate than the skirt with add seam at the center line. Second, the skirt with the 150cm width has higher efficiency rate than that of 110cm. Third, fixing the warp angle has higher efficiency rate than that of fixing the bias angle at the front and back center line. Finally, one direction per each size marker has much higher efficiency than the one direction marker.

• Korean Journal of Medicinal Crop Science
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• v.3 no.3
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• pp.195-199
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• 1995

These experiments were conducted to promote the rooting in tea cutting bymeans of several root media, growth regulators, cutting material and cutting condition The results are summarized as follows. The rate of rooting was higher in the softwood than in the hardwood, and the best cutting sea­son was about August 10 in the hardwood, about April 10 in the softwood. The most suitable root medium was the Masato at which the rate of rooting was 71%, 87% each in the softwood and in the hardwood. When growth regulators, such as oxyberon, rootone were sprayed upon the hardwood, the rate of rooting was promoted to 4 - 9 % better than that of no treatment. But such a good effect was not recognized significantly in the softwood.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.5
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• pp.391-399
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• 2017

This paper presents the effects of the cutting speed and feed rate on the axial shape of flat end-milled down cut side walls. Experiments were performed using the cutting speed, tool diameter, and feed per tooth as variables, and the thrust force and axial shape were measured as the experimental results. The results of this study confirmed that a smaller feed per tooth, which is proportional to the value obtained by dividing the feed rate by the cutting speed, results in a higher axial shape accuracy. In addition, the axial shape can be simplified to a form in which two straight lines having different slopes meet at a singular point. Therefore, it was concluded that the shape accuracy could easily be estimated during the operation and improved by adjusting the feed per tooth.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.1
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• pp.114-120
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• 2010

Optimization of the turning process has been concentrated on the selection of the optimal cutting parameters, such as cutting speed, feed rate and depth of cut. However, optimization of the cutting parameters does not necessarily guarantee the maximum profit. For the maximization of the profit, parameters other than cutting parameters have to be taken care of. In this study, 8 price-related parameters were considered to maximize the profit of the product. Regression equations obtained from RSM technique to relate the cutting parameters and maximum cutting volume with a given insert were used. The experiments with four combinations of cutting inserts and material were executed to compare the results that made the profit and cutting volume maximized. The results showed that the cutting parameters for volume and profit maximization were totally different. Contrary to our intuition, global optimization was achieved when the number of inserts change was larger than those for volume maximization. It is attributed to the faster cutting velocity, which decreases processing time and increasing the number of tool used and the total tool changing time.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.9
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• pp.89-95
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• 2001

Ceramic tool has to equip with not only high toughness and strength but also low thermal expansion and good thermal conductivity which leads to the high thermal shock resistance. These characteristics make it have longer tool life under thermal stress condition. In this study, commercial Si$_3$N$_4$ceramic cutting tool and home-made SiC based ceramic cutting tools which have different sintering time and chemical composition are tested under various cutting speed and the feed rate increase, the cutting force and the flank wear growth ratio increase, too. The performance of home-made SiC based ceramic cutting tool shows the possibility to be a new ceramic tool.

• Structural Engineering and Mechanics
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• v.61 no.4
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• pp.519-526
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• 2017

In the present paper, the effects of cutting parameters and coating material on the performances of cutting tools in turning of AISI 52100 steel are discussed experimentally. A comparative study was carried out between uncoated and coated (with TiCN-TiN coating layer) cermet tools. The substrate composition and the geometry of the inserts compared were the same. A mathematical model was developed based on the Response Surface Methodology (RSM). ANOVA method was used to quantify the effect of cutting parameters on the machining surface quality and the cutting forces. The results show that feed rate has the most effect on surface quality. However, cutting depth has the significant effect on the cutting force components. The effect of coating layers on the surface quality was also studied. A lower surface roughness was observed when using PVD (TiCN-TiN) coated insert. A second order regression model was developed and a good accuracy was obtained with correlation coefficients in the range of 95% to 97%.

• Journal of The Korean Society of Grassland and Forage Science
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• v.8 no.3
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• pp.104-109
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• 1988

A field experiment was conducted in order to investigate the seasonal changes of leaf growth and related characteristics in three cultivars of orchardgrass; Potomac, Kay and Sumas. The results were summarized as follows: 1. Leaf elongation was increased in a nearly linear phase during first and third cutting stages. It was increased slowly in early 10 days to 15 days after cutting and increased rapidly thereafter during the rest cutting stages. In cultivars, Potomac was showed hlgher leaf elongation than other cultivars during all cutting stages. There was no difference of leaf width within cutting stages, but the leaf width of fall regrowth was narrow. Sumas had relatively short and wide leaves. 2. Leaf dry weight and leaf area in first cutting stage were larger than others. Leaf area was increased rapidly from 15 days after cutting and leaf $we$ was increased rapidly from 20 days over all cutting stages. The increase in leaf area and dry weight were slow down after 30 days. 3. Number of epidermal cells was increased rapidly after cutting and the rate of increase was slow down after 30 days. In a cross section of leaf tissue, the part of mesophyll was occupied with about 60% of total area and larger area than other tissues. Leaf tissue had a large vacancy at early growth period after harvest and was filled gradually with mesophyll. This result was related to the increase of leaf dry matter.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.6
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• pp.20-26
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• 2003

This study proposes the construction of attractor quadrant method for high-precision cutting characteristics evaluation of non-ferrous metals. Also this paper aims to find the optimal cutting conditions of diamond turning machine by measuring surface form and roughness to perform the cutting experiment of non-ferrous metals, which are aluminum, with diamond tool. As well, according to change cutting conditions such as feed rate, using diamond turning machine to Perform cutting Processing, by measuring cutting force and surface roughness and according to cutting conditions the aluminum about cutting properties. Trajectory changes in the attractor indicated a substantial difference in fractal characteristics and attractor quadrant characteristics. In quantitative quadrant feature extraction, 1,309 point in the case of A17075 (one quadrant) and 1,406 point (one quadrant) in the case of brass were proposed on the basis of attractor reconstruction. Proposed attractor quadrant method can be used for high-precision cutting characteristics evaluation of non-ferrous metals.

• Korean Journal of Plant Resources
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• v.23 no.4
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• pp.368-373
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• 2010

Juniperus chinensis var. sargentii Henry is a short and creeping evergreen shrub which reaches about 60 cm in height and only occurs in the northeast Asia and in the top of high mountains over the Korea. The Korea Forest Service protects it strictly by law since J. chinensis var. sargentii is an eccentric plant and possibly may be exterminated soon in Korea. This study was carried out to develop the propagation technique by cutting for conservation of genetic resources of J. chinensis var. sargentii. The rooting responses of branch cuttings, obtained from hard(May) and semi-hard wood shoots (August) to four growth regulators, namely, IAA, IBA, NAA and Rooton(exceptionally powder method) applied at various concentrations(0, 100, 200, 500, 1000 and 2000 $mgL^{-1}$) were examined in mixed soil media. Rooting rate showed significant difference between cutting times, among kinds and among concentrations of growth regulators. The optimum cutting time was April to May in hardwood cutting. The application of IBA 1000 $mgL^{-1}$(rooting rate : 36.4%) was most effective in callus formation and rooting of cutting. Relatively, rooting of cutting of the control taken in May was 30.4%. Root characteristics such as number, length and diameter of root were not significantly affected by kinds and concentrations of growth regulators in hardwood cutting.