• The Journal of Korean Academy of Prosthodontics
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• v.34 no.4
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• pp.665-674
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• 1996

This study was designed to evaluate the effect of processing method and surface design on the transverse strength of repaired denture base resin. Three heat-cured denture base resins(Vertex, Lucitone, Lang), one cold-cured resin(Lang), and one light-cured resin(Dentacolor gingiva material) were used for repair purpose. The specimens for 3-point flexure test were fabricated by five processing methods such as self-curing, pressure pot, boiling water, processing, and light curing. Finally to evaluate the effect of surface designs for repaired resin, three surface designs(butt, bevel, inverse bevel) were tested. Within the limit of this study, following conclusions were drawn. 1. Lucitone denture base material showed highest flexural strength of $131.37{\pm}2.15MPa$, and there were significant differences in stength between Lucitone and other resins. 2. Between two different self curing methods, self curing repair resin, Lang, cured by pressure pot method showed highest flexural strength, $58.49{\pm}4.89MPa$. 3. Among the heat cured repair resins, maximum transverse strength value of $88.69{\pm}16.60MPa$ was recorded in Lucitone group cured by processing method. 4. Inverse bevel joint design showed significantly higher bond strength than butt joint group, Maximum bond strength was $59.36{\pm}1.33MPa$ in inverse bevel joint design group.

• Journal of The Korean Association For Science Education
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• v.22 no.3
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• pp.586-594
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• 2002

In this study, the relationships among cognitive conflict, situational interest, and conceptual change in studying boiling point were investigated. The differences in the relationships by gender were also investigate. Students of 7th grade(N=370) participated in this study. First, a preconception test was administered to choose students who possessed the misconception studied. After presenting anomalous data, test of response to anomalous data and state interest test were administered. After the instruction with a CAI program, a conception test was administered immediately. The conception test was administered again as a retention test four weeks later. The scores of both cognitive conflicts and state interest test were found to be significantly correlated with the scores of the conception test and the retention test. The results of multiple regression analysis indicated that state interest was significantly more important than cognitive conflict in prediction the degrees of conceptual change and retention of conception. For male students, state interest was the only significant predictor of conceptual change and retention of conception. In contrast, cognitive conflict was the only significant predictor for female students.

• Journal of the Society of Naval Architects of Korea
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• v.51 no.2
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• pp.114-121
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• 2014

Liquefied natural gas(LNG) cargo containment system(CCS) has the primary function of ensuring both adequate structural safety with respect to sloshing load which is defined as a violent behaviour of the liquid contents in CCS due to external forced motions and thermal insulation keeping natural gas below its boiling point. Among different LNG CCS types such as independent B-type and membrane ones, Mark III CCS is considered in this paper to perform its strength assessment. Mark III CCS plate is designed and constructed by stacking various non-metallic engineering materials such as plywood, triplex, reinforced PU foam that are supported by series of mastic upon inner steel hull structure. From the viewpoint of structural analysis, this plated structure is treated as a laminated composite structure showing complex structural behaviour under external load. Advanced finite element models of Mark III CCS plate is generated and used in conjunction with ultimate strength based failure criteria from laminated composite mechanics for the strength assessment. The strength assessment is performed within the initial failure state of Mark III CCS plate. Results provide failure details such as failure locations and loads. Finally obtained results are reviewed using the loads from acceptance criteria suggested by classification.

• Journal of the Korean Chemical Society
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• v.47 no.6
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• pp.541-546
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• 2003

Experimental vapor pressure measurements available in the literature for the inert gases have been rigorously analyzed and used to evaluate the constants A, B, C, D, and exponent of the following equation in the form of reduced vapor pressure and reduced temperature : $InP_r=A+{\frac{B}{T_r}+CInT_r+DT_n^r}$ According to varying exponent n all four constants have been obtained for the inert gases by the error analysis. This has provided us the best n and four constants for each of the inert gases ; Argon, krypton, xenon, helium, and neon. In order to obtain the calculated vapor pressure by the above equation, only the normal boiling point and the critical pressure and critical temperature are necessary to get the vapor pressure for an overall average deviation of 0.31 % for 406 experimental vapor pressure points consisting of five gases available in the literature. The average deviation for argon, krypton, and xenon is 0.24%, 0.09%, and 0.22%, respectively, for neon 1.31% and for helium 0.61%. These results are not unexpected in view of the significant quantum effects associated with helium and to a lesser degree with neon.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.5
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• pp.285-292
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• 2015

In this study, we were clearly identify the behaviour characteristics on particle size distribution of a condensing species by injection condition of HMDS (Hexa Methyl Di-Silazane, silica precursor that is one of liquid adsorbents) to remove condensing gaseous species as using pyroligneous liquor generated during carbonization process of biomass as precursor of condensing gaseous species. When using HMDS to remove the condensing gaseous species by growth machanism of particles, we could be controlled properly particles size such as amount of adsorbent injection, residence time, heating temperature and MFC flux. Especially, in case of using the silica precursor, in consideration of the physical and chemical properties of the boiling point, the specific gravity and the molecular weight, we found that the condensing species could be effectively controlled by particles granulation.

• Korean journal of applied entomology
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• v.31 no.2
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• pp.182-189
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• 1992

The influnces of 9 kinds of solvents on the toxicities against several insect species, phytotoxicity and solubility of compounds were evaluated by means of leaf dipping and spray methods. In case of the spray application, density and vapor pressure seemed to be a contributing factor to lethal toxicity against brown planthopper and diamond-back moth, respectively; the bigger the property of density and the smaller the vapor pressure gave the stronger toxicity. It appeared that the toxicity of solvents was not correlated with anyone of physical properties such as boiling point, dipole moment, dielectric constant, surface tension and viscosity. Spray treatment gave more toxicity to insects than leaf dipping treatment. Although dielectric constant and dipole moment seemed to be contributing factors to phytotoxic damage to rice seedling and bean plants, respectively, no general correlation between phytoxicity and the other physical properties was found. Leaf dipping application caused stronger phytotoxicity than spray application. It is concluded that 5% acetone solution may be most suitable to test chemicals because of its favorable solubility of compounds, lower toxicity to insects, and lower phytotoxicity.

• Journal of The Korean Association For Science Education
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• v.22 no.2
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• pp.252-260
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• 2002

The types and the characteristics of students' responses to anomalous data in studying 'boiling point' were investigated, and the degree of cognitive conflict and conceptual change were compared by students' cognitive variables. Tests regarding field dependence-independence and logical thinking ability, a preconception test, and a test of responses to anomalous data were administered to 137 sixth graders. Among them, 90 students whose preconceptions were consistent with the presented initial theory were selected. After learning the scientific concept, students' conceptual change was examined. Six types of responses identified were as follows: Rejection, reinterpretation, exclusion, uncertainty, belief decrease, and theory change. The main responses were rejection (33%) and theory change (39%). The results of Mann-Whitney U test indicated students who were field independent and had higher logical thinking abilities felt more cognitive conflict and exhibited more conceptual change.

• Polymer(Korea)
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• v.33 no.6
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• pp.620-624
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• 2009

Biomedical metal implants have been used clinically for replacement, restoration, or improvement of injury bodies based on high mechanical properties, but it has some risks such as the inflammatory, late thrombosis, or restenosis due to the low biocompatibility and toxicity. In various techniques of surface treatment developed to preserve these drawbacks, this study examined the electrospray coating technology with biodegradable poly (lactic-co-glycoic acid) (PLGA) on metal surface. Based on fundamental examination of electrospraying and solution parameters, the surface morphology of coated film was closely related to the boiling point of solvent, in-flight distance, and droplet size. The thickness of polymer film was linearly proportional to the emerged volume. This result exhibits that the polymeric droplets were continuously deposited on the polymer film. Therefore, the electrospray coating technology might be applied into the fabrication of single/multi-layered polymer film in nano-/micro-thickness and the control of the topology for biomedical metal implants including stents.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1563-1569
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• 1999

For the encapsulation of flavor compounds, maltodextrin (MD), gum arabic (GA) alkenylsuccinated modified starch (MS) and gellan gum were chosen for wall materials and their combination was optimized. Five fruit flavor compounds having boiling point of $90{\sim}200^{\circ}C$ were selected as core materials and their mixture was incorporated with rapeseed oil (flavor mixture to oil = 1 : 4). Flavor compound mixture to wall material ratio of 1 : 4 was selected, and the amount of maltodextrin was fixed to 30% of the wall material mixture. Gellan gum was selected as an additional wall material to increase emulsion stability. The optimum combination ratio of the wall material mixture for maximal total oil retention and minimal surface oil content is : 30.0% MD ; 26.4% GA ; 39.6% MS ; 4% gellan gum.

• Journal of the Korean Ceramic Society
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• v.40 no.11
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• pp.1113-1119
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• 2003

We used isopropanol which has low boiling point to prepare thin films at low temperature and changed mole concentration of zinc acetate from 0.3 to 1.3 mol/l. The structural, optical and electrical properties of ZnO thin films with Zn content were investigated. ZnO thin films highly oriented along the c-axis were obtained at Zn concentration of 0.7 mol/l. ZnO thin films with Zn concentration of 0.7 mol/l showed a homogeneous surface layer of nano structure. The transmittance of ZnO thin films by UV-vis. measurement was about 87% under the Zn concentration of 0.7 mol/l, but rapidly decreased over the 1.0 mol/l. The optical band gap energy was obtained from 3.07 to 3.22 eV which is very close to the band gap of bulk ZnO (3.2 eV). The electrical resistivity of ZnO thin films was about 150 $\Omega$-cm that shows little difference with Zn concentration. I-V curves of ZnO thin films exhibited typical ohmic contact properties.