• Transactions of the Korean hydrogen and new energy society
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• v.25 no.1
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• pp.87-96
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• 2014

Direct combustion characteristics of coal and oxygen carrier were measured in the thermogravimetric analyzer using four coals and two different oxygen carriers. The direct combustion efficiency decreased in order of Roto, Kideco, Sunhwa and Hyper coal for both oxygen carriers. Moreover, OCN703-1100 oxygen carrier showed better combustion efficiency than OCN706-1100 oxygen carrier for all four coals. The reduction characteristics of two oxygen carriers for $CH_4$, CO and $H_2$ gases were measured in the thermogravimetric analyzer to investigate why OCN703-1100 oxygen carrier showed better combustion efficiency than OCN706-1100 for all coals. The OCN703-1100 oxygen carrier represented higher reduction rate than OCN706-1100 for all reducing gases. Moreover, the total pore area and the porosity of OCN703-1100 were higher than those of OCN706-1100 oxygen carrier. The total volatile gas and volatile components of four coals were measured in a batch type fluidized bed reactor to investigate why the direct combustion efficiency decreased in order of Roto, Kideco, Sunhwa and Hyper coal for both oxygen carriers. The direct combustion efficiency was proportional to the total amount of ($CH_4+CO+H_2$) produced during devolatilization of coals.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.6
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• pp.625-630
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• 2007

Fractures of the mandibular condyle are account for between 26% and 57% of all mandibular fractures. Clinicians should decide how to treat the fractured condyle with many factors considered. Many surgical methods have been developed to reduction of fractured condyle and it' s internal fixation. In open reduction of fractured condylar neck and subcondyle, retromandibular approach offers a safe and effective approach for direct fixation due to easy access and low surgical morbidity.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.12-12
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• 2000

This paper consider a new weighted model reduction using block diagonal solutions of Lyapunov inequalities. With the input and/or output weighting function, the stability of reduced order system is quaranteed and a priori error bound is proposed. to achieve this, after finding the solutions of two Lyapunov inequalities and balancing the full order system, we find the reduced order systems using the direct truncation and the singular perturbation approximation. The proposed method is compared with other existing methods using numerical example.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.5
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• pp.27-34
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• 1998

This paper is on the discrete model reduction method over disc-type analytic domains. We define hankel singular value over the disc that is mapped by standard bilinear mapping. And the generalized singular perturbation approximation and the direct truncation are generalized to GSPA and DT over a disc. Furthermore, it is shown that the reduced order model over a smaller domaing has a smaller .inf.-norm error bound. And the poposed reduction method is used to obtain the regional pole placement property.

• KIEAE Journal
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• v.14 no.2
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• pp.87-98
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• 2014

This study is to identify quantitatively the function of carbon dioxide emissions reduction due to temperature and energy reduction according to direct carbon dioxide storage, shade provision, and evaportanspiration of urban park. According to the result of study, landscape tree indicated high carbon dioxide storage effect compare to bush, in which broadleaf tree indicated higher storage function than coniferous tree. It is believed to be the storage of carbon dioxide can be increased by increasing the composition rate of forest plants in the urban park. According to the direct estimation result of carbon dioxide storage in terms of example area, storage of carbon dioxide is estimated to be "seoul a zone" $476,818.8kg{\cdot}CO_2/m^2yr$, "anyang b zone" $186,435.7{\cdot}CO_2/m^2yr$, "daejeon c zone" $262,826{\cdot}CO_2/m^2yr$, "kwangju d zone" $231,657.8{\cdot}CO_2/m^2yr$. The carbon dioxide storage per unit area estimated to be "seoul a zone" $3.4{\cdot}CO_2/m^2yr$, "anyang b zone" $5.0{\cdot}CO_2/m^2yr$, "daejeon c zone" $2.6{\cdot}CO_2/m^2yr$, "kwangju d zone" $5.6{\cdot}CO_2/m^2yr$. The result of indirect carbon dioxide reduction effect estimated to be "seoul a zone" $291,603.4{\cdot}CO_2/m^2yr$, "anyang b zone" $165,462.4{\cdot}CO_2/m^2yr$, "daejeon c zone" $141,719.2{\cdot}CO_2/m^2yr$, "kwangju d zone" $154,803.4{\cdot}CO_2/m^2yr$. Carbon dioxide reduction potential amount through the urban park was increased to 1.6 times to 1.8 times when calculated to the indirect effect.

• Journal of Trauma and Injury
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• v.23 no.2
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• pp.175-179
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• 2010

Purpose: Sternal fractures after blunt thoracic trauma can cause significant pain and disability. They are relatively uncommon as a result of direct trauma to the sternum and open reduction is reserved for those with debilitating pain and fracture displacement. We reviewed consecutive 11 cases of open reduction and fixation of sternum and tried to find standard approach to the traumatic sternal fractures with severe displacement. Methods: From December 2008 to August 2010, the medical records of 11 patients who underwent surgical reduction and fixation of sternum for sternal fractures with severe displacement were reviewed. We investigated patients' characteristics, chest trauma, associated other injuries, type of open reduction and fixation, combined operations, preoerative ventilator support and postoperative complications. Results: The mean patient age was 59.3years (range, 41~79). The group comprised 6 male and 5 female subjects. Among 11 patients who underwent open reduction and fixation for sternal fracture with severe displacement, 6 cases had isolated sternal fractures and the other 5 patients had associated other injuries. Sternal fractures were caused by car accidents (9/11, 81.8%), falling down (1/11, 9.1%) and direct blunt trauma to the sternum (1/11, 9.1%), respectively. 3 of the 7 patients (42.9%) who underwent sternal plating with longitudinal plates showed loosening of fixation. Otherwise, none of the 4 patients who underwent surgical fixation using T-shaped plate had stable alignment of the fracture. Conclusion: Sternal fractures with severe displacement need to be repaired to prevent chronic pain, instability of the anterior chest wall, deformity of the sternum, and even kyphosis. In the present study, a T-shaped plate with a compression-tension mechanism constitutes the treatment of choice for displaced sternal fractures.

• Advances in environmental research
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• v.1 no.1
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• pp.37-55
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• 2012

Here we show that perchlorate reduction during pitting corrosion of zero-valent titanium (ZVT) is likely caused by dissolved titanium species, especially Ti(II). Several possible mechanisms were suggested based on the literature and were evaluated based on experimental observations. Direct reduction of perchlorate on the bare metal of the ZVT electrode was thermodynamically infeasible due to the high anodic potential that was applied. Other potential mechanisms were considered such as reduction by small ZVT metal particles released from the electrode and direct reduction on the oxide layer of the electrode where potential was sufficiently reduced by a high ohmic potential drop. However, these mechanisms were not supported by experimental results. The most likely mechanism for perchlorate reduction was that during pitting corrosion, in which ZVT is partially oxidized to form dissolved ions such as Ti(II), which diffuse from the electrode surface and react with perchlorate in solution. This mechanism is supported by measurements of the dissolution valence and the molar ratio of ZVT consumed to perchlorate reduced (${\Delta}Ti(0)/{\Delta}ClO_4{^-}$). The results shown in this study demonstrate that ZVT undergoing pitting corrosion has the capability to chemically reduce perchlorate by producing dissolved Ti(II) and therefore, it has the potential to be applied in treatment systems. On the other hand, the results of this research imply that the application of ZVT undergoing pitting corrosion in treatment systems may not be feasible now due to several factors, including material and electricity costs and possible chloride oxidation.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.4
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• pp.441-444
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• 1998

The negative direct-maternal genetic correlation $(r_{dm})$ for weaning weight is inflated when data are analyzed with model ignoring sire-by-year interactions (SY). An analytical study investigating the consequences of ignoring SY was undertaken. The inflation of negative correlation could be due to a functional relationship of design matrices for additive direct and maternal genetic effects to that for sire effects within which SY effects were nested. It was proven that the maternal genetic variance was inflated by the amount of reduction for sire variance; the direct genetic variance was inflated by four times the change for maternal genetic variance; and the direct-maternal genetic covariance was deflated by twice the change for maternal genetic variance. The findings were agreed to the results in previous studies.

• Journal of the Korean Society of Clothing and Textiles
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• v.27 no.11
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• pp.1300-1306
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• 2003

Cotton fibers were treated, with 1, 2, 3, 4-butanetetracarboxylic acid (BTCA) which is formaldehyde-free reagent to impart durable press performance. The dyeability, dyeing rate, and diffusion coefficient, of BTCA treated cottons were compared to prove the changes of pore size structure using direct dyes and disperse dyes. Diffusion coefficients of BTCA treated cotton fibers were determined at acidic conditions to figure out the effect of swelling. Since the dyeability of BTCA treated cotton fibers dyed with direct dyes were reduced, it is considered that the dyeability to direct dyes is related to the quantity of residual large pores. But, the dyeability to disperse dyes were increased due to the less reduction of small pore sizes and the increase of hydrophobicity in BTCA treated cotton cellulose. The dyeability to direct dye and disperse dye were decreased more at acidic conditions than at neutral conditions. It seemed that the swelling of pores in the fiber were inhibited.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.144-150
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• 2000

A field case study was performed to investigate optimum cropping technique of direct seeded rice. In addition, an economic analysis was made to see the effect of this method. Field study was performed at a 2.1㏊ paddy field in Kimjae city, Chonbuk province from 1991 to 1999. Various direct seeding method such as dryland seeding, wetland seeding, and no-till wetland seeding were introduced. Optimum cropping techniques such as when and how to manage the rotary till, water supply, herbicide application, and ponding depth were developed for different cropping methods. Based on this study ￦640,000 per ㏊ can be saved by direct seeding due to no nursery cost, and ￦l,220,000 per ㏊ can be saved by no-till and no nursery cost. With further study these cropping techniques including the no-till direct deeding proves to be advantageous these can be adopted for the most of the paddy fields in Korea.