• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.6
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• pp.39-49
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• 2015

This study was to evaluate the growth and spatial distribution characteristics of Rhus javanica population. The study was conducted between 2015 January and July at the cut-slope revegetation site in Dae-Ji Mountain. Seeds of native species were sowed on the disturbed cut-slope in 2002. There were 119 vascular plant species 55 families and 94 genera on the cut-slope. Compositae, Rosaceae, and Leguminosae plants were dominant species, which are pioneer species in dry and barren site. Canopy of trees covered 44.1% total area, which was 8.3% increase from 2008. Rhus javanica, main species, dominated all DBH classes except DBH >24cm. Albizzia julibrissin showed high frequency in the 6~17cm DBH class and Salix koreensis was abundant at >12cm. Elaeagnus umbellata, Corylus heterophylla var. heterophylla, Alnus sibirica, and Acer pictum were not observed. Rhus javanica population was the most frequently observed on the south facing cut-slope. The average DBH of Rhus javanica was $7.3({\pm}3.7)cm$ and the average height of them was $5.2({\pm}1.7)m$. Annual average DBH growth was 7.9mm/yr and the maximum growth(12.0mm/yr) was the $3^{rd}$ year. It decreased after $6^{th}$ years. Although Rhus javanica population in the Dae-Ji Mountain was a seed originated plantation, the forest had reverse J shape diameter frequency distribution. It indicated that the forest is uneven-aged forest. The Rhus javanica population was expected to sustain.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2001.04b
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• pp.39-40
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• 2001

This experiment was conducted to investigate the effect of root zone heating on the growth of cut minirose Rosa hybrida L. ′Little Marble′ in winter season. Effects of four different root zone temperatures of 16, 20, 24$^{\circ}C$ and non-heating control on the growth and productivity were compared. Harvested cut-flowers were measured for stem length, stem diameter, fresh and dry weights, numbers of leaves, stems and flowers, days to flower, and chlorophyll concentration. The results showed that mean height was the greatest at 16$^{\circ}C$. Days to flower was the shortest at 24$^{\circ}C$. Fresh and dry weights of top (shoot＋leaf＋flower), shoot and leaf were the greatest at 2$0^{\circ}C$. Stem and flower numbers were the greatest at 16$^{\circ}C$, but leaf number was the greatest at 2$0^{\circ}C$. Mean cut flower yield was the greatest at 16$^{\circ}C$. Chlorophyll concentration was slightly higher at 16$^{\circ}C$, but was not significantly different among the treatments. Stem diameter was the greatest at 2$0^{\circ}C$. Dry matter was the greatest at 24$^{\circ}C$. Total yield of cut rose stems increased with increasing temperature. Combined heating could save 24% in fuel cost as compared to the air heating alone. The results obtained suggested that optimal root zone temperature for the growth of cut rose "Little Marble" was 2$0^{\circ}C$, and the greenhouse heating energy can be saved by minimal air heating combined with root zone heating to 2$0^{\circ}C$.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.08a
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• pp.119-125
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• 1999

At Wire Rod Mill Plant, wire is made of the billet produced at continuous casting machine, or rolled bloom produced at billeting mill, and the product can be classified of wire of 5.5${\Phi}$ and bar in coil of 14∼42${\Phi}$ in diameter(bar in coil will be referred to as coil as below). At present, wire is produced at POSCO No.1, 2, 3 WRM, coil at garret line of No. 2 WRM. Head and tail of coil are properly cut and treated to scrap to fulfill the customer's satisfaction. This above cutting is done off line, and small size coil can be cut manually with clipper, large size coil with hydraulic cutter. Nowadays, it is being investigated to cut automatically in line with trimming shear after passing mill stand. At the moment, Because the coil produced at the garret line of No.2 WRM is hot 400∼600$^{\circ}C$ and trimming is done manually with cutter, there are always interference from manual operation or safety problem of bad working condition. Not only because of the diversity of the coil size 14∼42${\Phi}$ in diameter, but because of the rolling speed 2.5∼22m/sec, it is required to be equipped with several trimming shear. But this can be accomplished with only one shear installed proper place at this paper.

• Journal of Bio-Environment Control
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• v.13 no.3
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• pp.130-134
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• 2004

Experiments were conducted to evaluate quality and vase life of cut rose ‘Rote Rose’ cultivated either in soil or hydroponically in rockwool. Rose stems were put in four different preservative solutions, 0.5% chrysal RVB, BS (2% sucrose + 200 mg. L$^{-1}$ 8HQS + 0.3% Chrysal RVB), Sonk1 (BS + 0.1 mM ethionine), and double distilled $H_2O$. Flower stems were displayed at $20\pm1^{\circ}C$, RH 60%, and light intensity of $8.1\mu$mol.$m^{-2}$ .$s^{-1}$ provided by fluorescent lamps for 16 hㆍ$d^{-1}$ Fresh weight and flower diameter during vase life were affected by cultivation method and were greater in hydroponically-grown roses than in soil-grown roses. Among preservative solutions, BS and Sonkl were superior to Chrysal RVB in terms of extending vase life. Vase life of cut rose in Chrysal RVB, BS, and Sonkl over the control was prolonged by about one day.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.2
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• pp.118-123
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• 2016

Overlap cutting is a fundamental method of applying abrasive water jet (AWJ) machining to milling to produce a wider surface because the nozzle outlet is approximately 1.0 mm wide. In this study, the effects of overlap cutting on the depth profile and surface roughness are investigated. The overlapping area depends on the amount of step over, which is controlled in the pick-feed direction. If the step over is equal to or larger than the diameter of the nozzle, no overlap cut occurs but large cusps remain between the cut paths. A step over as small as one-thirds of the nozzle diameter may lead to triple-overlap cutting resulting in an extraordinary depth. By using pocket milling experiments with a step over of 0.46 (or 0.47), it is verified that AWJ can produce a milled surface of titanium, one of the hard-to-cut materials, with $76{\mu}m$ Ra.

• Journal of Plant Biology
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• v.16 no.1_2
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• pp.1-5
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• 1973

Six young trees of Alnus tinctoria grown in isolation, each having different growing stage, were selected and the surface area of their roots, stems and leaves was determined. Each of the roots of more than 0.2mm in diameter and stems was cut at intervals of 10cm and their surface area was calculated with 2$\pi$rl from the average diameter (2r) of both sections (upper and lower) by making cylindrical estimation of the cut pieces. The leaf area measured was only one side area, and the volume of cut piece and amount of dry matter of each organ were also measured. The percentage to the surface area of the whole plant body by each organ was 4-12% in root, 7-9% in stem and 69-89% in leaf, respectively. There was relatively a little individual difference. However, the surface area ratios of root and stem showed a slightly increasing tendency while that of leaf decreasing according to the growing stage. The ratio of sum leaf area index (LAIi) was 2.3-4.0$m^2$/$m^2$-and that of the surface area index(SaIi) was 0.16-0.33$m^2$/$m^2$, respectively. It has been known that the stem surface area(SAI) to the leaf area index(LAI) is within the range of 31-53%, but the SAIi is within the range of 8-11% of the LAIi.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.10a
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• pp.183-189
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• 1997

This research is a experimental study for the machining conditions of E. D. M. They were used Cu electrode and the various amplitude of current waves for the machining by E.D.M. By the analyse the characteristics of current, voltage, roughness of surface and over cut, the next results were obtained. E.D.M. machining time become to be more longer by the increasing the tensile stress. In case of NAK 55 as the composite resin, the machining time was more faster without the relationship for the tensile stress. And if it was more increased the amplitude of Ip, it has been more faster in the machining time and more poor in the surface roughness. But it was increased Ip with 5A, it has been increased 0.3 time in over cut. So, if we want to be the precision machining, the diameter of the electrode should be more smaller than the diameter of machined hole in workpiece with E.D.M.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.5
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• pp.87-95
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• 2000

The numerical analysis and the experiments are carried out to develop the design program for the flow control valve attached to the vane pump for power steering. The factors affecting the flow rate characteristics are analyzed by the experiments and the numerical analysis. The results are summarized as follows; (1) the main factors affecting to the first and second control flow rate are the diameter of big and small rod of the spool. (2) the cut off is mainly affected by the main spring constant, the initial displacement of main spring and the small diameter of the spool. (3) the dropping slope characteristics are decided by the chamfer of spool and the dynamic characteristics of the spool.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.09a
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• pp.216-219
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• 2001

In this study, a hydrocyclone operated by centrifugal force was examined as a part of dredge system of lake sediments. It does not help dehydration of the sediments, but also enables the classification of fine particles in the stable and sanitary treatment. Several experiments were performed focusing on the separation efficiency under the condition of room temperature with virtual sediment samples and simulated particles. As a result of the experiment, it was found that the apex size of the cyclone greatly affected the cut diameter(d$_{50}$), and high density particles were separated more effectively.y.

• Transactions of Materials Processing
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• v.24 no.3
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• pp.181-186
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• 2015

Many in the industrial world that consume high amounts of energy are trying to reduce energy when manufacturing their products. Energy saving during manufacturing is a cost reduction. Reduced cost is necessary for profit improvement. The Piston Under Drive Brake used in the current study is an automotive transmission part. The original machining after hot forging was changed to machining after cold forging of a plate in order to save energy and cost. Two extrusion shapes along the outer diameter caused decreased tool life because of the interrupted cut during turning. Therefore, a thickness reduction of two extrusion areas in the outer diameter was needed. The current study suggests an effective way to reduce the thickness of interrupted cut by using progressive blanking.