• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.2
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• pp.113-118
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• 2011

This study was aimed to develop blend films by rice by-product (rice-hull and rice-bran) and bio-degradable materials. The rice by-product was firstly prepared from the pulverizing for making fine powder. Bio-degradable materials could be prepared by melting at high temperature. The mixture of the fine powder of rice by-product and melted bio-degradable materials was then blended and cast into films. The obtained films were investigated on their morphology, secondary structures and properties by using SEM, ICP and ASTM, respectively. Mechanical properties and degradability of these films were measured and compared to those of the PE films. Mechanical strength of bio-films was higher than that of PE films, however elongation ratio showed lower percent than that of PE film. In addition, bio-film could be degraded into fragments within 3 months under the field condition of normal upland crop cultivation. Bio-degradable mulching film indicated great potential for agronomic use as a new source of bio-degradable material.

• Journal of Engineering Education Research
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• v.11 no.2
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• pp.79-89
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• 2008

The purpose of this study is to research the women engineers' recognition with a triangulation method and make suggestions on desirable education in engineering. The research period is for about 4 months from December 15, 2007 to April 4, 2008. The objects of the research are two groups of female engineers at D college located in the metropolitan area - the first group had 187 women engineering majors, 3 women graduate students and 2 women professors in engineering department, and the second group had 5 women engineering majors who once stayed out of school temporarily, 4 women engineering graduates, and 5 graduates who are currently working. The second group is intently selected in order to look into the detailed factors that affect the recognition of women engineers. The methods of the research varied and included were surveys on the web, personal interviews, focus meetings, surveys by e-mail and telephone, etc. The results of the study show what the women engineers want in engineering education includes to have role models of women engineers who can cast a vision to them, get a leadership training especially for when they lead a group that has both man and woman members. It was also found that experincing a cooperative learning through diverse projects is essential to build basic character training and competency, and practical education is required for the major or becoming a full time worker.

• Applied Chemistry for Engineering
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• v.18 no.5
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• pp.483-489
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• 2007

Polyaniline (PANI)/Polyimide (PI) membranes were prepared and the effects of PANI contents and doping on the structural properties and gas separation properties were studied. The polyamic acid (PAA) solution was prepared by the polycondensation reaction of 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) and 4,4'-oxydianiline (ODA) in 1-methyl-2-pyrrolydinone (NMP) solvent. The PANI/PI blends were obtained by mixing PAA solution and PANI solution, and were doped with 1 M aqueous HCl solution for 24 h. The structural characterizations of the as-cast and doped membranes were examined by FT-IR, XRD, and TGA. The gas permeation experiments with $H_2$, $CO_2$, $O_2$, $N_2$, and $CH_4$ were carried out by variable pressure method at $30^{\circ}C$ and 5 atm. For all gases tested, the permeability coefficients of the blends decreased with increasing PANI content and the magnitude of permeability was in the order of $H_2$ > $CO_2$ > $O_2$ > $N_2$ > $CH_4$. The permeability for PANI/PI membranes decreased after the doping process while the permselectivity increased. For $H_2/CH_4$ separation, the doped PANI/PI (75/25) membrane has a permselectivity of 991.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.3
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• pp.92-103
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• 2015

Development of new concrete bridge deck system with FRP plank using as a permanent formwork and the main tensile reinforcement recently has been actively conducted. Concurrent use as a reinforcing material and a permanent formwork, it is possible to reduce the construction time and construction costs than the usual concrete slab. In this study, an experiment was carried out for the bond stress between cast-in-place concrete and the type of FRP plank using as a permanent formwork. The interfacial fracture energy that can be one of the most important parameters were evaluated for adhesion performance and bond stress to know the characteristics of the failure mechanism of the adhesion surface. Interfacial fracture energy of normal concrete is 0.24kN/m of GF11 case, in the case of GF21, 0.43kN/m appears, in the case of CF11 and GF31, 0.44kN/m and 0.46kN/m respectively it appeared. In case of RFCON, 0.52kN/m appears from GF12, the CF12 and GF22, 0.51kN/m and 0.36kN/m appeared each case.

• Journal of Biomedical Engineering Research
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• v.25 no.5
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• pp.383-389
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• 2004

A commercially pure Ti(CP-Ti) and Ti-25wt％Pd alloy for dental applications were cast into a phosphate-bonded Al$_2$ $O_3$/ $SiO_2$ investment mold and the surface of the casting specimens were investigated by means of SEM/EDS, XRD and XPS. The addition of 25wt％Pd in CP-Ti showed a moderate mold reaction owing to the considerable lowering of melting point. XRD analysis of the investment after burn-out treatment revealed that it consisted essentially of $SiO_2$, Al$_2$ $O_3$, P$_2$O$\_$5/, Mg$_3$(P $O_4$)$_2$, AlP $O_4$, Mg$_2$ $SiO_4$, MgAl$_2$ $O_4$ The mold reaction products were Ti$\_$5/Si$_3$ and Ti $O_2$ in case of CP-Ti casting and Ti $O_2$ and SiO$\_$x/ in case of Ti-25wt％ Pd casting.

• Archives of Reconstructive Microsurgery
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• v.18 no.2
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• pp.55-61
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• 2009

Purpose: To analyze the clinical and radiologic results of the shoulder arthrodesis in brachial plexus injury patients with flail upper extremity. Material and Method: From Aug 1978 to April 2008, 29 shoulders in 29 patients with brachial plexus injury with shoulder fusion, we evaluated 20 shoulders in 20 patients, more than 1 year follow up. The average follow-up period was 6.45years (range: 1year~24years). There were 13 men and 7 women, and the mean age at the time of trauma was 32.0years(2~65 years). The type of injury was a motorcycle accident in 11 patients, in car accident in 5, pedestrian accident in 3, and fall from a height in 1. The lesion of injury was root and trunk in 1 patient, trunk and cord in 1, trunk in 18. Surgery was performed on the whole arm type paralysis in 12 patients, lower arm type paralysis in 8 patients. The preoperative visual analog scale score was 8.7(7~10). When the trapezius and serratus anterior muscle were in function, operation was performed. 18 patients were processed to the additional operation. Gracilis free flap in 6 patients, neurotization in 3, Steindler flexor plasty in 6, and tendon transfer in 3 were performed. Fixation was conducted with cancellous screws in 13 patients, Knoles pins in 5, and cancellous screws and Knoles pins in 2. The position of the arthrodesis at operation was $28.5^{\circ}$($20~45^{\circ}$) in abduction, $30.3^{\circ}$($20~45^{\circ}$) in flexion, and $30.8^{\circ}$($20~40^{\circ}$) in internal rotation. Result: The follow up visual analog scale score was 3.4(0~7). Postoperatively, shoulder spica cast was applied for 15.3weeks(8-20weeks). The median time to bony union was 17.7weeks(9~28weeks). Average range of motion was $32.0^{\circ}$($15~40^{\circ}$) of abduction, $24.0^{\circ}$($10~40^{\circ}$) of flexion, and $18.5^{\circ}$($10~30^{\circ}$)of internal rotation. Conclusion: The shoulder fusion in brachial plexus injury patients is one of the good methods to relieve pain, improve the function and stabilize the flail shoulder joint.

• Korean Journal of Ecology and Environment
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• v.39 no.2 s.116
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• pp.226-235
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• 2006

Populations of Zacco koreanus, distributed in four different tributaries of mid-upper reach Nakdong River were investigated to analyze a length-weight relation and von Bertalanffy's growth model. Fish sampling was conducted by common method (cast net and kick net) during March to October 2005. Fishes caught in the field were identified immediately, and then individuals of Zacco koreanus were preserved in 10% formalin to further measure their total length and weight in the laboratory. As the results of the equation based on length-weight relation, values of parameter b on the population of all tributaries were greater than 3.0 and the value on Bohyeon Stream was the maximum (3.26), indicating that the fish in the stream became more rotund as the length increases. In the mean time, we examined Brody growth constant (k) induced by the von Bertalanffy's growth model, and we found more steady state population in Wi (-0.18) and Byeongbo (-0.21) Streams than in fan (-0.38) and Bohyeon (-0.37) Streams. The findings would be used to assess local water environment on tributaries of the Nakdong River with understanding of ecological characteristics on the population of Zacco koreanus, as well as provide us fundamental information on domestic study of fish ecology.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.3
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• pp.20-27
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• 2014

In the construction site, various earth retaining systems are developed and applied to maintain stability of excavated area and structures. Among the methods, the underground continuous wall and the column-type diaphragm wall methods are especially used in construction site nearby buildings or roads. However, these methods have some disadvantages such as the difficulty of quality control and long curing time because these methods need to cast fresh concrete at the construction site. In addition, these methods are usually applied to the site for the temporary purpose. In this paper, we suggest precast hollow prestressed concrete pile for continuous pile wall system. To investigate the structural behavior of suggested pile, which is the main member of the suggested system, tests pertaining to the structural behavior and prestressing force applied in the pile are conducted. From the test results, it was found that the prestressing force measured is sufficient compared with the value obtained by the design equation and the cracking moment measured is 34% higher than the design value. In addition to the above, this precast hollow prestressed concrete pile has an additional safety margin that the maximum moment is 59.2% higher than the cracking moment which is one of the serviceability limits for the design of the system.

• Proceedings of the KACD Conference
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• 2001.05a
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• pp.235-237
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• 2001

;Dentistry has benefited from tremendous advances in technology with the introduction of new techniques and materials, and patients are aware that esthetic approaches in dentistry can change one's appearance. Increasingly. tooth-colored restorative materials have been used for restoration of posterior teeth. Tooth-colored restoration for posterior teeth can be divided into three categories: 1) the direct techniques that can be made in a single appointment and are an intraoral procedure utilizing composites: 2) the semidirect techniques that require both an intraoral and an extraoral procedure and are luted chairside utilizing composites: and 3) the indirect techniques that require several appointments and the expertise of a dental technician working with either composites or ceramics. But, resin restoration has inherent drawbacks of microleakage. polymerization shrinkage, thermal cycling problems. and wear in stress-bearing areas. On the other hand, Ceramic restorations have many advantages over resin restorations. Ceramic inlays are reported to have less leakage than resin restoration and to fit better. although marginal fidelity depends on technique and is laboratory dependent. Adhesion of luting resin is more reliable and durable to etched ceramic material than to treated resin composite. In view of color matching, periodontal health. resistance to abrasion, ceramic restoration is superior to resin restorationl. Materials which have been used for the fabrication of ceramic restorations are various. Conventional powder slurry ceramics are also available. Castable ceramics are produced by centrifugal casting of heat-treated glass ceramics. and machinable ceramics are feldspathic porcelains or cast glass ceramics which are milled using a CAD/CAM apparatus to produce inlays (for example, Cered. They may also be copy milled using the Celay apparatus. Pressable ceramics are produced from feldspathic porcelain which is supplied in ingot form and heated and moulded under pressure to produce a restoration. Infiltrated ceramics are another class of material which are available for use as ceramic inlays. An example is $In-Ceram^{\circledR}$(Vident. California, USA) which consists of a porous aluminum oxide or spinell core infiltrated with glass and subsequently veneered with feldspathic porcelain. In the 1980s. the development of compatible refractory materials made fabrication easier. and the development of adhesive resin cements greatly improved clinical success rates. This case report presents esthetic ceramic inlays for posterior teeth.teeth.

• Journal of Hydrogen and New Energy
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• v.9 no.1
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• pp.16-24
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• 1998

Recently Zr-based $AB_2$ type hydrogen absorbing alloy has received much attention as a negative electrode material for the Ni-MH batteries because of its high capacity. In this study $ZrV_{0.1}Mn_{0.7}Ni_{1.2}$ alloy was chosen and the effects of heat treatment and a partial substitution of the Mo in Mn site on the various electrode properties were investigated. The alloys was prepared by arc melting (as-cast sample). Some of them were heat treated at $1,100^{\circ}C$ for 4 hours. After this they were differentiated by the different cooling rates of slow cooling and quenching. Various electrode characteristics such as activation process, high rate dischargeability and self discharge characteristic were investigated with the three types of electrodes. It was found that heat treated alloys resulted in an increase in plateau flatness of P-C isotherms however both discharge capacity and high rate capability were decreased. And the partial substitution of Mo for Mn in $ZrV_{0.1}Mn_{0.7}Ni_{1.2}$ alloy improved the self-discharge characteristic without the loss of discharge capacity (300mAh/g).