• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.88-95
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• 2005

The head to disk spacing must be decreased to increase recording densities in hard disk drives. Recently, to decrease the head to disk spacing, smooth disk having no bumps onto the lading zone has used. In this research, we compared the number of particles generated in HDD with smooth and textured disks. We used a sampling method using a particle sampler and a CPC (condensation particle counter) to detect particles in HDD. First, we sampled and counted panicles generated with disk rotational speed and various rest times when the smooth disk and textured disks were used, then analyzed the sampled particles by SEM (scanning electron microscopy) and AES (auger electron spectroscopy). In results of measuring particles, more particles in case of LZT disk drive generated than that of the smooth disk drive in all test modes. The number of particles generated in the smooth disk was very low. The particle generation increased as the rest time increased (smooth/LZT disks) and more particles in case of LZT disk drive generated than that of the smooth disk drive. In results of analyzing particle components, Al, Ti, Si components were detected and we could not found differences between components in case of smooth/LZT disk drive.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.3
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• pp.187-192
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• 2009

Out of all oral malignant tumor, malignant lymphoma occurs in only 3.5%. Especially, most of the primary malignant lymphomas, which occur in the head & neck region are high-grade diffuse large B-cell lymphoma and mucosa-associated lymphoid tissue (MALT) marginal zone B-cell lymphoma is very rare. In the head & neck region, malignant lymphoma is reported to occur in the thyroid, salivary gland, trachea, larynx, orbital lobe and the Waldeyer's ring. Among the Waldeyer's ring, palatal tonsil is reported to be the most common region, but, only 1 case report was published in Korea. Until now, there were no case reports of MALT lymphoma that occurred in the tongue. The purpose of this case report is to report and discuss on a case of MALT lymphoma of the tongue.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.2
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• pp.33-38
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• 2010

To survive head-to-head competition, we should keep our labor productivities above those of other nations. However, our labor productivities are low compared to those of the developed countries. It is the well-known fact that we make up for the productivities with long work hours. Entering the line of developed nations safely and enjoying well-being age freely, we need to achieve high labor productivities without sacrificing work hours. What would be a fine solution? Back to the basics! Although it is important to enforce R&D on high-tech products, we should have so-called bluebird philosophy, being faithful to the basics and trying to find solutions at a stone's throw. Basics of basics may be unceasing improvement, establishing reasonable standard times, and maintaining them. To support going back to the basics, this thesis proposes VITAMAX, a motion and time study software. As VITAMAX stands for "Visual Improvement and Time Analysis for Maximizing Profits", it provides a simple and powerful visual tool which is useful for improving manual works and determining standard times. Since VITAMAX is based on the Microsoft Excel and VBA, it is very cost-effective and easy to use. VITAMAX may contribute to the profit increase of manufacturing companies, especially for the small and medium-sized enterprise.

• Transactions of the Society of Information Storage Systems
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• v.2 no.2
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• pp.123-129
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• 2006

The head to disk spacing must be decreased to increase recording densities in hard disk drives. Recently, to decrease the head to disk spacing, smooth disk having no bumps onto the lading zone has used. In this research, we compared the number of particles generated ill HDD with smooth and textured disks. We used a sampling method using a particle sampler and a CPC (condensation particle counter) to detect particles in HDD. First, we sampled and counted particles generated with disk rotational speed and various rest times when the smooth disk and textured disks were used, then analyzed the sampled particles by SEM (scanning electron microscopy) and AES (auger electron spectroscopy). In results of measuring particles, more particles in case of LZT disk drive generated than that of the smooth disk drive in all test modes. The number of particles generated in the smooth disk was very low. The particle generation increased as the rest time increased (smooth/LZT disks) and more particles in case of LZT disk drive generated than that of the smooth disk drive. In results of analyzing particle components, Al, Ti, Si components were detected and we could not found differences between components in case of smooth/LZT disk drive.

• Korean Journal of Poultry Science
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• v.24 no.4
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• pp.185-191
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• 1997

In order to obtain the basic information needed to utilize poultry by-products as feed resources, the yielding ratio, chemical composition and nutrient bioavailability of 5 offal components such as autoclaved head, feet, viscera, blood and feathers were investigated. Yielding ratios of head, feet, viscera, blood and feathers were 2.93％ 4.78％, 10.98％, 3.91％ and 4.83％, respectively. The crude protein contents of feathers (86.71％) and blood (82.99％) were higher than those of viscera (64.67％), feet (58.76％) and head (49.51％) , Inversely, the crude fat contents of blood (6.96％) and feathers (2.96％) were lower than those of head (26.19％), viscera (23.96％) and feet (13.73％). The crude ash contents of feet (21.69％) and head (20.38％) were higher than those of other by-products (0.96∼8.62％). The macro-mineral contents of head and feet were higher than those of other components, and the iron content of blood was higher than the other by-products. The total amino acid contents of poultry by-products showed the same trend as the crude protein contents. In addition, the Iysine content of feathers was very low compared to its high protein content. The essential amino acid contents of feathers were poorer than those of other offal components. Among the 5 offal components, the feathers showed the poorest amino acid availabilities. The ME contents were highest in viscera, and head, blood, feathers and feet. in decreasing order.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2004.11a
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• pp.355-361
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• 2004

Ceramic femoral heads in the total hip replacement have been developed to reduce the polyethylene liner wear, Alumina and zirconia (3Y-TZP) having the excellent tribological properties are coupled against acetabular cups of polyethylene and are used in clinical application worldwide. However, alumina has a risk of catastrophic failure, and zirconia has the low temperature degradation in spite of enhanced fracture toughness. Recently, novel zirconia/alumina composite is very attractive due to the low temperature degradation (LTD)-free character and high fracture toughness. In the present study, we focus on the wear of ceramic on ceramic, which are able to be used as femoral heads and acetabular cups. Therefore, LTD-free zirconia/alumina composites with three compositions are made in a form of disk and cylinder, and the wear of the composites is performed on pin-on-disk type wear tester. The wear is conducted with or without lubricant. All the composites fabricated with the different composition show the good wear resistance.

• Magazine of the Korean Society of Agricultural Engineers
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• v.16 no.1
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• pp.3293-3301
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• 1974

An experimental work was conducted by using a laboratory-made model dryer to investigate the effect of the rate of natural forced-air on the drying rate of rough rice which was deposited in the deep-bed. The dryer consisted of 8 cylinderical containers with grain holding screen at their bottoms, each of which having 30cm in diameter and 15cm in height. The containers were sacked vertically with keeping them air-tight by using paper tape during dryer operation. Two separate layers of containers were operated in the same time to have two replications. The moisture contents of grains within each bins after predetermined period of dryer operation were determined indirectly by measuring the weight of the individual containers. The air-rates were maintained at 6 levels, or 5, 8, 10, 15, 18 and 20 millimenters of static head of water. The roomair conditions during dryer operation were maintained in the range of 10-l5$^{\circ}C$ in temperature and 40-60% in relative humidity. The results of the study are summarized as follows: 1. Drying characteristics of the grains in the bottom layers were approximately the same regardless of airdelivery rates, giving the average drying rate as about 0.35 percent per hour after 40-hour drying period, during which moisture content (w. b.) reduced from 24 percent to about 10 percent. 2. After about 40-hour drying period, the mean drying rates increased from 0.163 percent per hour to 0.263 percent per hour as air-flow rates increased from 5mm to 87.16mm of static head of water. In the same time, the moisture differences of grains between lower and upper layers varied from 12.7 percent at the air rate of 5mm of water head to 7.5 percent at the air-flow rate of 20mn of water head. Thus, the greater the air-flow rate was, the more overall improvement in drying performance was. Additionally, from the result of ineffectiveness of drying grain positioned at 70cm depth or above by the air rate of 5mm of static head of water it may be suggested in practical application that the height of grain deposit would be maintained adequately within the limits of air-rates that may be actually delivered. 3. Drying after layer-turning operation was continued for about 30 hours to test the effectiveness of reducing moisture differences in the thick layers. As a result of this layer-turning operation, moisture distribution through layers approached to narrow ranges, giving the moisture range as about 7 percent at air-flow rate of 5mm head of water, about 3 percent at 10mm head about 2 percent at 15mm head, and less than 1 percent at 20mm head. In addition, from the desirable results that drying rate was rapid in the lower layers and dully in the upper layers, layer-turning operation may be very effective in natural air drying with deep-layer grain deposit, especially when the forced air was kept in low rate. 4. Even though the high rate of air delivery is very desirable for deep-layer natural-air drying of rough rice, it can be happened that the required air delivery rate could not be attained because of limitation of power source available on farms. To give a guide line for the practical application, the power required to perform the drying with the specified air rate was analyzed for different sizes of drying bin and is given in Table (5). If a farmer selects a motor of which size is 1 or {{{{1 { 1} over {2 } }}}} H.P. and air-delivery rate which ranges from 8~10mm of head, the diameter of grain bin may be suggested to choose about 2.4m, also power tiller or other moderate size of prime motor may be recommended when the diameter of grain bin is about 5.0m or more for about 120cm grain deposit.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.5
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• pp.371-379
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• 2016

In the ship design process, ship motion and propulsion performance in sea waves became very important issues. Especially, prediction of ship propulsion performance during real operation is an important challenge to ship owners for economic operation in terms of fuel consumption and route-time evaluation. Therefore, it should be considered in the early design stages of the ship. It is thought that the averaged value and fluctuation of effective inflow velocity to the propeller have a great effect on the propulsion performance in waves. However, even for the nominal velocity distribution, very few results have been presented due to some technical difficulties in experiments. In this study, flow measurements near the propeller plane using a stereo PIV system were performed. Phase-averaged flow fields on the propeller plane of a KVLCC2 model ship in waves were measured in the towing tank by using the stereo PIV system and a phase synchronizer with heave motion. The experiment was carried out at fully loaded condition with making surge, heave and pitch motions free at a forward speed corresponding to Fr=0.142 (Re=2.55×106) in various head waves and calm water condition. The phase averaged nominal velocity fields obtained from the measurements are discussed with respect to effects of wave orbital velocity and ship motion. The low velocity region is affected by pressure gradient and ship motion.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.3
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• pp.227-232
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• 2006

Rice quality must certainly be considered as one of the primary preference for consumers. On aspect concerns marketing, such attributes as appearance, physicochemical characteristics, and palatability of brand rice are very important. Therefore this study was carried out to observe the quality of commercial brand rice in Gyeongbuk Province, Korea from 2002 to 2004. In seasonal changes of mean air temperature from early July to middle August, it was lower in 2003 by $0.8{\sim}3.3^{\circ}C$ than that in normal year. Among the rice quality characteristics, the cv of percentage of head rice and palatability (Toyo value) were very low but those of chalky rice and protein content were very high during three years, and the same tendency was also observed among the brands. The average percentages of head rice were 92.5% in 2002, 89.9% in 2003 and 93.3% in 2004, respectively. On the contrary, the percentages of chalky rice were higher in 2003 as 4.9% than those in 2002 (3.9%) and in 2004 (2.8%). These results were caused by the abnormal meteorological conditions in 2003. Due to the higher protein content (8.0%) in 2003, the palatability was deteriorated to 71.0. However the protein content in 2004 was reduced to 7.0% and this result improved the palatability to 77.0.

• The KSFM Journal of Fluid Machinery
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• v.17 no.6
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• pp.104-108
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• 2014

The recent Fukushima nuclear power plant accidents shows that the core make up at high RCS pressure condition is very important to prevent core melting. The core make up flow at high pressure condition should be driven by gravity force or passive forces because the AC-powered safety features are not available during a Station Black Out (SBO) accident. The reactor Coolant System (RCS) mass inventory is continuously decreased by releasing steam through the pressurizer safety valves after reactor trip during a SBO accident. The core will be melted down within 2~3 hours without core make up action by active or passive mode. In the new design concept of a Hybrid Safety Injection Tank (Hybrid SIT) both for low and high RCS pressure conditions, the low pressure nitrogen gas serves as a charging pressure for a LBLOCA injection mode, while the PZR high pressure steam provides an equalizing pressure for a high pressure injection mode such as a SBO accident. After the pressure equalizing process by battery driven initiation valve at a high pressure SBO condition, the Hybrid SIT injection water will be passively injected into the reactor downcomer by gravity head. The SBO simulation by MARS code show that the core makeup injection flow through the Hybrid SIT continued up to the SIT empty condition, and the core heatup is delayed as much.