• Tribology and Lubricants
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• 제19권4호
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• pp.223-229
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• 2003

The sliding wear characteristics of the crane sheave were investigated using a pin-on-disk rig tester. The experiment was conducted using a high carbon steel wire that was upper material, also carbon steel castings that was disk material. There are various operating conditions in this work. At the room temperature, we carried out the wear test under a grease lubrication and dry condition. The results of wear test showed that an annealed-casted have lower, also the wear curves are linearly increased with increasing of sliding distance. For the specific wear rate of annealed-casted, the wear resistance was increased with decreasing diameter of wire. The wear of a wire and a disk have a different mechanism, the one is the abrasive wear due to fatigue wear under lubrication, another is the adhesion wear under dry condition.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2003년도 학술발표논문집
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• pp.603-606
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• 2003

This study was carried out to investigate the effects of T-P concentrations in irrigation water on the growth, yield, and grain quality of rice. It acquire fundamental knowledges to set up irrigation water quality standards. The pot experiment was conducted with 5 treatments using irrigation waters. It consisted of various total phosphorus concentrations(control, 1, 2, 5, 10mg/L) and replicated four times with randomized block design. The results of this study showed that as T-P concentrations in irrigation water increases, plant height tended to increase. Dry weight of rice plant at T-P 10mg/L was significantly higher than the control. However, T-P in irrigation water did not affect plant height, tiller number, plant dry weight, yield, and quality of rice.

• Wind and Structures
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• 제8권2호
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• pp.135-146
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• 2005

Divergent galloping-like motion of a dry inclined cable has been observed in a limited number of experimental studies, which, due to the uncertainties in its onset conditions, has induced serious concerns in the bridge stay cable design. A series of dynamic and static model wind tunnel tests have been carried out to confirm the existence of the phenomenon and clarify its excitation mechanism. The present paper focuses on exploring the spatial flow structure around an inclined cable. The pattern of resultant aerodynamic forces acting at different longitudinal locations of the model and the spatial correlation of the forces are examined. The results lead one step closer in revealing the physical nature of the phenomenon.

• 대한치과의사협회지
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• 제12권7호
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• pp.521-526
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• 1974

This observation was carried out to investigate the inorganic constituents of dental calculus of varying locations and different ages. Supragingival calculus was obtained from 540 patients with the periodontal disease. The results were as follows : 1. The weight loss rate in ashing by aging was the highest in the 2nd decade (63.7%) and followed in order by 3rd decade (60.8%), seventh decade 959.8%), fourth decade (55.9%), sixth decade (52.6%) and fifth decade (43.2%). 2. The weight loss rate by ashing was more prominent in the buccal surfaces of the upper posterior teeth (62.0%) than in the lingual surface of the lower anterior teeth (59.7%). 3. The difference in contents of the inorganic constituents by sex was not remarkable. (male, Ca:373.0 P:333.9, female, Ca: 380.2, P: 339.6 ㎍/mg dry weight) 4. In the dry calulus, contents of the inorganic constituents were as follows: Ca:325.8 P:269.10 Mg:1.21 Na:8.44 K:1.32, Zn:0.67 ㎍/mg. 5. The Ca/P ratio was the lowest in the upper anterior region (1.11) and the highest in the lower posterior region (1.29) and the average was 1.20.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.385-388
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• 1997

As the environmental regulations become stricter, new machining technologies are being developed which takes envi ronmenta 1 aspects into account . Since cut t ing oi I has some impact on environment. many researches are being carried out to minimize the use of cutting oi I. The methods for minimizing cutting oil usage includes the following techniques: I ) Cooling of tools and work piece. 2) Useage of compressed cooling air for the removal of chip. 3) Minimal useage of environment-friendly vegetable cutt:ngoiI for lubrication between chip and tools. Since the turning machine is continuous, tools are under constant thermal load and tool wear increases as the lubricative performance degrades. Also surface roughnesses have a direct influence on turning. In order to examine the characteristics of turningmachining, this work investigates experimentally the degree of tool wear and characteristics of surface roughness in relation to machining conditions, supply methods, and cooling methods.

• Plant Resources
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• 제4권2호
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• pp.97-101
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• 2001

This study was carried out to determine the effect of sowing time on the flowering, growth and yield of Schizonepeta tenuifolia Briquet. Emergence and flowering dates in the sowing time from March 30 to April 30 were earlier than those of the other sowing times. In the sowing time from March 30 to April 30, length and diameter of main stem, number of node per main stem, number of branch per plant and fresh, and dry weight of stem were greater than those of the other sowing times. Yield components such as ear length, main stem length and diameter, branches per plant, number of node and ears per plant, yield of stem in fresh and dry were the highest at the sowing time from March 30 to April 30. Optimum sowing time of Schizonepeta tenuifolia Briquet were shown to be from March 30 to April 30 in southern areas of Korea.

• International Journal of Industrial Entomology and Biomaterials
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• 제4권2호
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• pp.143-147
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• 2002

Studies on the interrelationship between biological yield and harvest index, and their association with shoot rearing were carried out in 9 promising mulberry genotypes, which indicated significant variations among genotypes. Biological yield had close association with leaf yield components indicating that they are inter-related for higher productivity in mulberry, Biological yield revealed highly significant positive correlation with important leaf yield components. However height of the longest branch showed negative correlation with biological yield. Genotypes with higher biological yield associated with low ratio of stem weight to leaf weight and high Harvest index on dry weight basis are to be selected for shoot rearing. Biological yield recorded on fresh weight basis had less impact on the present study in comparison to dry weight basis.

• Journal of the Korean Wood Science and Technology
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• 제39권1호
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• pp.21-27
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• 2011

This study was carried out to examine properties of water resistant plywood by using serum protein adhesive which is natural, environment-friendly and human-friendly. For the preparation of the serum protein adhesive, pig blood from slaughterhouse was centrifuged and serum was separated from corpuscles and concentrated to 30% by dry weight basis. This concentrated serum protein was modified with PF resin (50% NVC) with the ratio of 9 : 2.5. Plywood made by this modified serum protein gave 1.21 N/$mm^2$ of dry bonding strength, 0.80 N/$mm^2$ of wet boil bonding strength, 0% of cyclic delamination test value, and 0.025 ppm of HCHO emission, which met the excellent super $E_0$ grade and water resistant plywood.

• 대한기계학회논문집A
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• 제27권11호
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• pp.1873-1880
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• 2003

The sliding wear characteristics of the crane sheave were investigated using a pin on disk rig tester. The experiment was conducted using a high carbon steel wire that was upper material, also carbon steel castings that was disk material. There are various operating conditions in this work. At the room temperature, we carried out the wear test under a grease lubrication and dry condition. The results of wear test showed that an annealed-casted have lower, also the wear curves are linearly increased with increasing of sliding distance. For the specific wear rate of annealed-casted, the wear resistance was increased with decreasing diameter of wire. The wear of a wire and a disk have a different mechanism, the one is the abrasive wear due to fatigue wear under lubrication, another is the adhesion wear under dry condition.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 추계학술대회 논문집
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• pp.28-33
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• 2004

At present, industry and researchers are looking for ways to reduce the use of lubricants because of ecological and economical reasons. Therefore, metal cutting is to move toward dry cutting or semi-dry cutting. This paper presents an investigation into MQL(Minimum Quantity Lubrication) machining with the objective of deriving the optimum cutting conditions for the turning process of SM45C. To reach these goals several finish turning experiments were carried out, varying cutting speed, feed rate and oil quantity, with MQL. The surface roughness results of tests were measured and the effects of cutting conditions were analyzed by the method of Analysis of Variance(ANOVA). From the experimental results and ANOVA, it is found that a better surface roughness can be obtained by decreasing oil quantity and feed rate.