• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.37 no.3
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• pp.41-49
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• 2005

Styrofoam as shock-absorbing materials for packaging has been regarded as one of non-biodegradable products leading to soil contamination at a landfill and release of dioxine during its incineration. For avoiding severe burdens on our environments by styrofoam, it must be replaced by environment-friendly materials. In order to evaluate availability of pulp fibers as a substitute for styrofoam, various extrusion processes were applied for making optimal biodegradable products. Then thermomechanical pulp fibers made of Pinus radiata and Pinus rigida were uniformly mixed with other additives such as starch and polyvinyl alcohol prior to expansion. The physical properties of the final products were examined by measuring expansion efficiency, compression strength, and elastic modulus. Wheat starch played a key role to maintain optimal flowing conditions within the barrel of the extruder irrespective of addition of soluble starch and polyvinyl alcohol. However, as the amounts of wheat starch in raw-materials increased, the elastic modulus of the expanded materials greatly increased. High elastic modulus is not suitable as shock-absorbing products for packaging. Thus the wheat starch must be added at a minimum if possible, that is, below 20% based on oven-dried weight of pulp fibers. the elastic modulus of the expanded products was decreased as their moisture contents increased. For the products containing 20% wheat starch, the lowest elastic modulus, 844.64 kPa was obtained under 10% of the moisture content. This was similar to that of styrofoam.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.3
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• pp.1058-1062
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• 2011

After the design and production of cold rolling to make titanium-alloyed(Gr.9) eyerim, the function of the roller was evaluated. The surface roughness values of the roller of Ra was $0.05{\sim}0.156{\mu}m$ and of Rz was $0.23{\sim}067{\mu}m$. The values showed a satisfactory result compared with the surface roughness values Ra was $0.04{\mu}m$ and Rz was $0.3{\mu}m$ which was measured after barrel polishing for the titanium eyeglasses frame PVD (Physical Vapor Deposition) gilding. As a result of cold rolling of Ti-3Al-2.5V (Half Titanium), the degree of hardness increased to 221Hv, 247Hv(1st), 270Hv(2nd), etc. Therefore, it was found that proper heat treatment and multi-stand rolling process are necessary.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.2
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• pp.44-50
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• 2010

Recently, the crude oil price per one barrel in 2005 cost 49.4 dollars. But the value of crude oil in 2007 had ascended 68.4 dollars which was skyrocketed 38.5[%] owing to the sudden rise of energy price. As it has been growing the necessity of energy efficiency, energy intentive companies actively try to implement energy management system It has been studied to improve the energy saving for household sector using the smart metering system which can give the information of energy prices, pattern on real time to energy consumers and voluntarily lead the activities of energy saving. In this paper, we estimated potential benefits and value of smart metering system through california test.

• Journal of Korean Society of Rural Planning
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• v.22 no.4
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• pp.61-69
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• 2016

In order to reduce the farmers' burden of purchasing agricultural machinery and address the shortage of farm workers, the government have been promoting agricultural machinery rental service since 2003. Despite of political purpose, the outcome of agricultural machinery rental service turned out to be adverse, high cost and low efficiency, by the pork barrel projects operated from some municipalities. Therefore, this study was aimed to improve the efficiency of agricultural machinery rental service by analyzing the operation status of agricultural machinery in local government. A questionnaire survey was conducted at 134 cities and counties in terms of rent type, management personnel, business budget, agricultural machinery ownership, rental performance, use rates, operational problems, and improvement plan. This study found that some agricultural machinery rental offices were only focused on the short-term rental service, which caused the increasing number of operating personnel, required facilities/equipment. The short-term rental service has a limitation for promoting the mechanization rate in dry-field farming. Therefore, it should be carried out along with the long-term rental service which a lessee maintains and manages agricultural machinery directly. Furthermore, the reasonable number of agricultural machinery based on regional circumstances should be considered to meet rental demand and collect the minimal rental fee for purchasing new agricultural machinery and replacing old ones.

• Tribology and Lubricants
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• v.22 no.4
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• pp.190-195
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• 2006

A simple and effective analysis method is presented for gaining a complete transient temperatures on the internal and external surfaces of a 40 mm gun tube subjected to a series of rapid firings. Two series of temperature data for both Hs and As were measured by using two rapid response k-type surface thermocouples near the firing origin and the muzzle. With other available temperature data, patterns of temperature variations of the gun tube as a function of time variable were driven through complete evaluations of the data. It is found that overall temperature gradients which increase exponentially toward saturation temperature, actually consist of a series of linear temperature gradients corresponding to the firing sequences. Under the similar firing sequences, patterns of temperature variations fur both the surface temperatures near the chamber and those near the muzzle were found to have linear temperature gradients with different values and the same response frequencies, i.e. they had peaks and lows in temperatures at the same time. The resultant complete temperature data can be used as the fundamental bases for analysis of thermoelastic properties of the materials such as thermal strain and stress, and f3r the prediction of cannon tube life-time through calculation of wear rate.

• Archives of Plastic Surgery
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• v.33 no.5
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• pp.637-642
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• 2006

Purpose: Incidence of chronic osteomyelitis in femur is lower than that of tibia due to abundantsurrounding soft tissue like muscles and subcutaneous fat. However, if the femur is infected, surgical approach would be very difficult because of surrounding soft tissue and bony defects would be getting larger due to the late detection. Chronic osteomyelitis of femur is an intractable disease with frequent recurrence and remained bone instability in spite of multiple classical operations. Methods: From August 1998 to October 2005, we had 7 cases of fibular osteocutaneous free flap to reconstruct the femur. Those were followed-up for 23 months. All 7 cases were male. 4 cases were in midshaft and the others are distal part of femur. Results: The 7 cases that had not been healed in spite of average 9.1 times previous operations were reconstructed successfully without the recurrence of chronic osteomyelitis. Continuous rehabilitation therapy and brace were very helpful for the ambulation. It took 5.6 months for complete union of bone, and 9.8 months for the ambulation. Conclusion: After wide resection, reconstruction of the femur using fibular osteocutaneous free flap guaranteed bone stability and prevented recurrence of osteomyelitis through rich blood supplying fibula and muscle. Double barrel graft of fibula would be needed in case of the sufficient strength and thickness of femur. We report the successful results of reconstruction of femur with fibular osteocutaneous free flap for chronic osteomyelitis of femur.

• Development and Reproduction
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• v.15 no.3
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• pp.231-237
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• 2011

The objective of this study was to elucidate the dynamics of microtubules in post-ovulatory aging in vivo and in vitro of mouse oocytes. The fresh ovulated oocytes were obtained from oviducts of superovulated female ICR mice at 16 hours after hCG injection. The post-ovulatory aged oocytes were collected at 24 and 48 hours after hCG injection from in vivo and in vitro, respectively. Immunocytochemistry was performed on ${\beta}$-tubulin and acetylated ${\alpha}$-tubulin. The microtubules were localized in the spindle assembly, which was barrel-shaped or slightly pointed at its poles and located peripherally in the fresh ovulated oocytes. The frequency of misaligned metaphase chromosomes were significantly increased in post-ovulatory aged oocytes after 48 hours of hCG injection. The spindle length and width of post-ovulatory aged oocytes were significantly different from those of fresh ovulated oocytes, respectively. The staining intensity of acetylated ${\alpha}$-tubulin showed stronger in post-ovulatory aged oocytes than that in the fresh ovulated oocytes. In the aged oocytes, the spindles had moved towards the center of the oocytes from their original peripheral position and elongated, compared with the fresh ovulated oocytes. Microtubule organizing centers were formed and observed in the cytoplasm of the aged oocytes. On the contrary, it was not observed in the fresh ovulated oocytes. The alteration of spindle formation and chromosomes alignment substantiates the poor development and the increase of disorders from the post-ovulatory aged oocytes. It might be important to fertilize on time in ovulated oocytes for the developmental competence of embryos with normal karyotypes.

• Journal of Microbiology and Biotechnology
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• v.26 no.10
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• pp.1701-1707
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• 2016

Lipoxygenase (LOX) is an industrial enzyme with wide applications in food and pharmaceutical industries. The available structure information indicates that eukaryotic LOXs consist of N terminus β-barrel and C terminus catalytic domains. However, the latest crystal structure of Pseudomonas aeruginosa LOX shows it is significantly different from those of eukaryotic LOXs, including the N-terminal helix domain. In this paper, the functions of this N-terminal helix domain in the soluble expression and catalysis of P. aeruginosa LOX were analyzed. Genetic truncation of this helix domain resulted in an insoluble P. aeruginosa LOX mutant. The active C-terminal domain was obtained by dispase digestion of the P. aeruginosa LOX derivative containing the genetically introduced dispase recognition sites. This functional C-terminal domain showed raised substrate affinity but reduced catalytic activity and thermostability. Crystal structure analyses demonstrate that the broken polar contacts connecting the two domains and the exposed hydrophobic substrate binding pocket may contribute to the insoluble expression of the C terminus domain and the changes in the enzyme properties. Our data suggest that the N terminus domain of P. aeruginosa LOX is required for its soluble expression in E. coli, which is different from that of the eukaryotic LOXs. Besides this, this N-terminal domain is not necessary for catalysis but shows positive effects on the enzyme properties. The results presented here provide new and valuable information on the functions of the N terminus helix domain of P. aeruginosa LOX and further improvement of its enzyme properties by molecular modification.

• Journal of the Korea Institute of Military Science and Technology
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• v.4 no.2
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• pp.256-262
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• 2001

Viscous solutions of supersonic side jet nozzle and supersonic jet impinging on a flat plate are simulated using three-dimensional Navier-Stokes solver. For rapid and abrupt control of a missile in supersonic flight, side jet on a missile body is found to be a useful devise as evidenced by recent missile development at several nations. The magnitude of the side jet and the duration of it decide the level of control of such a missile system. The aerodynamic characteristics of the side jet devise itself are examined in terms of key parameters such as the side jet nozzle geometry, the chamber pressure and temperature. On the other hand, the jet impinging flow structure exhibits such complex nature as shock shell, plate shock and Mach disk depending on the flow parameters. Among others, the dominant parameters are the ratio of the nozzle exit pressure to the ambient pressure and the distance between the nozzle exit plane and the impinging plane. As the plate is placed close to the nozzle, the computed wall pressure at or near the jet center oscillates with large amplitude with respect to the mean value. The amplitude of wall pressure fluctuations subsides as the plate/nozzle distance increases, and the frequency of the wall pressure is estimated on the order of 10.0 KHz. Objectives of this paper are to show accurate simulation of nozzle flow itself and to demonstrate the jet flow structure when the jet interacts with a wall at a close range.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.4
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• pp.447-455
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• 2018

If a hidden enemy is shooting, there is a threat against soldiers in recent conflicts. This paper aims to improve the localization of a muzzle using microphone array. Gunshot noise can provide information about the location of muzzle with two signals, the muzzle blast from the gun barrel and the projectile sound from the bullet. Two signals arrive to the microphone array with different arrival time and angle. If the arrival angles of the two signals are estimated, distance between sniper location and the microphone array can be calculated by using geometric principles. This method was established in 2003 by Pare. But this method has a limitation that it cannot calculate the distance when the arrival angles of the two signals are same. Also it has an error when the angle difference of arrival is small. In order to overcome this limitation, a new method is proposed that uses the change of characteristic of the projectile sound with respect to vertical distance from the trajectory. The proposed method estimates the distance correctly when the arrival angle of two signals are same, and when the angle difference between two signals is increased, the estimation error increases with respect to the angle. Therefore these two methods can be selected according to the angle difference between two signals to estimate the distance of the muzzle. Below the threshold of the angle difference, the proposed method can be used to estimate distance with smaller error than the existing method. This was demonstrated by shooting tests using actual sniper rifles.