• Journal of the Korean Society of Safety
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• v.24 no.2
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• pp.7-12
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• 2009

The machining process of ceramics can be characterized by cracking and brittle fracture. In the machining of ceramics, edge chipping and crack propagation are the principal reasons to cause surface integrity deterioration. Such phenomenon can cause not only poor dimensional and geometric accuracy, but also possible failure of the ceramic parts. Thus, traditional ceramics are very difficult-to-cut materials. Generally, ceramics are machined using conventional method such as grinding and polishing. However these processes are generally costly and have low MRR(material removal rate). To overcome such problems, in this paper, h-BN powder, which gives good cutting property, is added for the fabrication of machinable ceramics by volume of 10 and 15%. The purpose of this study is an analysis of endmill's rake angle for appropriate tools design and manufacturing for the machinable ceramics. In this study, Experimental works are executed to measure cutting force, surface roughness, tool fracture, on different axial rake angle of endmills. Cutting parameters, namely, feed, cutting speed and depth of cut are used to accomplish purpose of this paper. Required experiments are performed, and the results are investigated.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2001.11b
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• pp.35-42
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• 2001

In order to obtain basic information for pure line breeding of hemp which is effective on the pure line preservation and propagation, three varieties were investigative from 1995 to 1996 at Mokpo Experiment Station, Honam Agriculture Experiment Station, and cutting parts, cutting times, cutting length and storage duration after cutting of plant were observed. Higher rooting ratio were observed in cutting of shoot and later branch, in July 5, optimum harvesting time and 5 days after harvesting time, in shorter storage duration,0 and 2 days. Also there were the highest rooting ratio increased by from 12% to 16% in shorter cutting of 10cm than 15cm long cutting in shoot, lateral branch and stem cuttings. Hemp cv. Korea showed higher rooting ratio than the other varieties, Japan and Turkey. Therefore, it was concluded that hemp, a dioecious plant, could be effectively propagated for the pure lines by cutting method, especially in cv. Korea.

• Korean Journal of Plant Resources
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• v.34 no.4
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• pp.270-277
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• 2021

Veronica rotunda var. subintegra (Nakai) T. Yamaz. is perennial herb belonging to the family Scrophulariaceae, native to Korea. Plant growth regulators, cutting mediums, cutting position, and leaf size were examined to investigate the requirements for cutting propagation of V. rotunda var. subintegra. This study was conducted over a period of 6 weeks from March to May 2017 in the Division of Plant Resources, Korea National Arboretum. For all treatments, survival and rooting percentage was 100%. In PGRs experiment, the number of roots and shoot length treated with 100 mg/L IBA treatment was significantly higher than that of NAA treatment. The shooting percentage was decreased with an increase of the PGRs concentration. In growing substrates experiment, the number of roots on commercial soil (61.2) was the highest, followed commercial + kanuma soil (45.7), and the lowest was kanuma soil (41.8). The shoot length treated with commercial soil (8.9 cm) was significantly greater than that of kanuma soil (4.1 cm). In cutting positions experiment, the number of roots treated with apical (56.6) was significantly higher than that of basal (38.8). In leaf-cut experiment, the number of roots and of shoot length treated with full leaf was significantly higher than that of half leaf. As a result, we recommend treating cuttings with 100 mg/L IBA treatment, commercial soil, apical position, and full leaf for successful cutting propagation of V. rotunda var. subintegra.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.10a
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• pp.64-69
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• 2003

This paper describes a study on the tearing damage of the ship's bottom plating during a grounding. It has been known widely that difference scaling laws are applied for bodies undergoing simultaneously plastic flow and crack propagation in the deformation of the plate tearing. Especially, the basic scaling law is not followed for the fracture. In this study plate cutting experiments for the geometrically similar models have been performed in order to verify the problem. From the experimental results, it has been observed that the cutting forces and energy for the larger models are significantly lower than those of the smaller models the damage become large. A simplified analytical method for the estimation of tearing is proposed based on the experiments and it has been observed that the results of the present formula are correlated very well with the experiments

• Journal of Ocean Engineering and Technology
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• v.18 no.1
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• pp.41-46
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• 2004

This paper describes a study on the tearing damage of a ship's bottom plating, during a grounding. It is widely known that different scaling laws are applied for bodies undergoing simultaneous plastic flow and crack propagation in the deformation of plate tearing. Specifically, the basic scaling law is not followed for the fracture. In this study, in order to verify the problem, plate cutting experiments for geometrically similar models have been performed. From the experimental results, it has been observed that the cutting forces and energy for the larger models are significantly lower than those of the smaller models. A simplified analytical method for the estimation of tearing is proposed, based on the experiments. It has been observed that the results of the present formula are highly correlated with the experiments.

• Journal of the Korean Institute of Landscape Architecture
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• v.20 no.3
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• pp.57-63
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• 1992

The present investigation was undertaken to determine if CO2 enrichment promoted rooting and subsequent growth of Lagerstroemia indica L. cuttings. Cutting were taken from the one-year-old semihardwood twigs, and rooted in enclosed propagation frame with enriched CO2 levels (500-2000ppm) regulated by a gas monitor. The base of each cutting was dippid from 500 to 4000ppm naphthalenacetic acid. Roothing was determined after 3 months. CO2 enrichment during roothing increased the rooting percentage and number of roots per cutting, but nontreated cuttings rooted in low percentages producing one or two roots. The length of new shoots and dry weight of whole cuttings in CO2 enrichment were significantly greater than those of the atmospheric controls. The organic and inorganic compounds concentraion were measured as an indication of nutritional state in whole cuttings. As a result of CO2 enrichment, carbohydrate, protein and inorganic compounds(total nitrogen, P2O5, K2O, CaO, MgO) concentration were higher than controls.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.11
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• pp.189-198
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• 1998

Recently, monitoring of tool life is a matter of common interesting because tool life affects precision, productivity and cost in machining process. Especially flank wear has a direct effect on cutting mechanism, so the various pattern of cutting force is obtained experimentally according to variation of wear condition. By investigating cutting force signal, AR(Autoregressive) modeling and correlation dimension analysis is conducted in turning operation. In this modeling and analysis, we extract features through 6th AR model, correlation integral and normalized correlation integral. After the back-propagation model of the neural network is utilized to monitor tool life according to flank wear. As a result. a very reliable classification of tool life was obtained.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.1
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• pp.34-39
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• 1987

This study was conducted to find out the adequate cutting method for propagation and the optimum treat-ing time of GA$_3$ to enhance the fruit setting of Pepino (Solanum muricatum AIT). Mixture of peat moss (50%) and vermiculite (50%) shows the best rooting for the Pepino stem cuttings. An active rooting was observed 15 days after the cuttings were treated with 1,000 ppm of NAA. Application of GA$_3$ at flowering stage was effective for fruit setting of Pepino and fruit setting was the most satisfactory when GA$_3$ was sprayed over the flowers.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.429-437
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• 2019

This study was conducted to examine the effect of humidification and shading during cutting propagation on growth and development of strawberry (Fragaria x ananassa Duch.) 'Maehyang' plants at a propagation stage. The runner cuttings were stuck on Nov. 23, 2017 in propagation benches set in a Venlo-type glasshouse. Four shading treatments, no shading (control, C), 55% shading with white lawn (W55), 55% black shading net (B55), or 100% black plastic film (B100) with either an intermittent fog system (H) or without fog system. The shading and fog systems were removed 2 weeks after sticking of strawberry cuttings. A nutrient solution for strawberry, which was developed by Yamazaki, was supplied once a day with electrical conductivity (EC) $1.6dS{\cdot}m^{-1}$ and pH 5.8. Growth parameters such as plant height, longest root, crown diameter, leaf chlorophyll, leaf area and fresh and dry weight were measured at 7 days and 26 days after sticking. There was no significant difference in growth of above-aerial part of strawberry. The overall growth of the strawberry roots was better grew by providing fog than that not provide fog. The root fresh weight and root dry weight after 26 days after sticking of strawberry cutting was the best in the treatment that provided fog system without shading (CH). The longest root after 26 days after sticking of strawberry cutting was the best in the treatments that provided fog system with either 55% white lawn (W55H) and 55% black shading net (B55H). These results suggest that morphogenesis of these plants were affected by humidification and shading types. In a broader perspective, these results can be used to optimize studies of other crops grown from cuttings.

• Journal of agriculture & life science
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• v.45 no.4
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• pp.73-80
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• 2011

This study was conducted to elucidate the best cutting condition in propagation of Juniperus chinensis var. sargentii in respect of survival rate, rooting rate, and early growth after cutting via process of cutting time, cutting media, cutting type and growth regulators. As for cutting time, rooting rate was 68.3% on April, which was higher than 39.5% on May and 32.5% on June. The best cutting media was stream sand of rooting rate 72.7%. Those of mixed soil and decomposition were 40.1% and 27.5% each. The effect of growth regulators was different according to the kind of cutting media. There was no effect on stream sand media which showed the highest rooting rate, while it was very effective on the media of decomposition of granite, which rooting rate showed the lowest. Hardwood as cutting materials showed somewhat higher survival and rooting rate compared to semi-hardwood. The cutting with hardwood condition to stream sand on April, it is regarded to be the most effective condition for Juniperus chinensis var. sargentii to increase survival and rooting rate. Therefore in this experiment it is considered that the best season cutting is April, and the most useful media and plant materials stream sand, and hardwood respectively.