• Elastomers and Composites
• /
• v.54 no.4
• /
• pp.279-285
• /
• 2019

Bio-based polyester polyols were synthesized using esterification with azelaic acid, sebacic acid, and 1,3-propanediol. Polyurethanes were prepared using chain extenders (1,4-Butanediol, 1,3-Propanediol, and isosorbide) and 4,4'-diphenylmethane diisocyanate with a mixing ratio of 1:1:1.1. Subsequently, the properties of the polymers prepared using the different chain extenders were compared. The synthesis of polyurethane was confirmed by FT-IR, TGA, and GPC. The mechanical properties (hardness, ball rebound, and tensile strength) of the materials were analyzed using shore A tester, taber abrasion, and UTM. heat, chemical, and water resistances of the prepared materials were measured by comparing the tensile strengths according to external changes.

• Language and Information
• /
• v.7 no.2
• /
• pp.117-137
• /
• 2003

This paper attempts to provide an alternative analysis involving categorical issues related to English gerunds. Especially, this paper rejects Maulof's approach that creates a new syntactic category gerund by mixing nominal and verbal categories. This paper identifies two syntactic structures in English gerunds: nominal gerunds and verbal gerunds. This distinction is based on syntactic and semantic characteristics of each type and is intended to account for the external distribution and endocentricity of the construction. Treating verbal gerunds syntactically as verbal categories, this paper proposes that English verbal gerunds act like other verbal categories such as infinitives whereas nominal gerunds behaves much like derived nominals. This paper proposes a few lexical rules that can take care of the two types of gerunds. The proposal can be extended to prepositional complements as well as sentential subject positions. This proposal not only resolves the issues involving distributional properties of the gerund construction but also captures syntactic parallelism observable between gerunds and other verbal constructions in English.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2021.11a
• /
• pp.36-37
• /
• 2021

When the final finish of a building is designed with base concrete, complex deterioration occurs due to the harsh environment such as shrinkage and expansion due to external temperature changes, freezing and thawing, and the use of calcium chloride due to snow accumulation. Therefore, the pozzolanic reaction mechanism of blast furnace slag is clearly identified, and the causal relationship between the material properties and performance of the blast furnace slag is identified to present guidelines for mixing high-durability concrete.

• Korean Journal of Food Science and Technology
• /
• v.42 no.4
• /
• pp.398-406
• /
• 2010

The purpose of this study was to determine the optimal mixing ratios for three different concentrations of maltodextrin, dehydration time, and cutting thickness to prepare gingers using molecular press dehydration (MPD) through response surface methodology (RSM) based on the dehydration rate, rehydration rate, and a sensory evaluation. As maltodextrin concentration increased, dehydration rate, rehydration rate, external, flavor, texture, overall acceptability of the gingers tended to be high, and the color tended to be low. As the dehydration time and cutting thickness increased, dehydration rate, rehydration rate and the sensory evaluation of the gingers tended to be high. The maltodextrin concentrations were 70-82%, dehydration time was 5.2-9.2 hr, and cutting thickness levels were 1.0-1.2 mm. The optimal mixing ratios, maltodextrin concentration, dehydration time, and cutting thickness for manufacturing the best quality of gingers using molecular press dehydration were 76%, 7.2 hr, and 1.1 mm, respectively.

• Membrane and Water Treatment
• /
• v.13 no.4
• /
• pp.201-208
• /
• 2022

Emulsion Liquid Membrane (ELM) is a prominent technique for the separation of heavy metal ions from wastewater due to the fast extraction and is a single-stage operation of stripping-extraction. The selection of the components (Surfactant and Carrier) of ELM is a very significant step for its preparation. In the ELM technique, the primary water- in-oil (W/O) emulsion is emulsified in water to produce water-in-oil-in-water (W/O/W) emulsion. The water in oil emulsion was prepared by mixing the membrane phase and internal phase. To prepare the membrane phase, the extractant D2EHPA (di-2-ethylhexylphosphoric acid) was used as a mobile carrier, Span-80 as a surfactant, and Paraffin as a diluent. Moreover, the internal (receiving) phase was prepared by dissolving sulphuric acid in water. Di-(2- ethylhexyl) phosphoric acid such as surfactant concentration, carrier concentration, sulphuric acid concentration in the receiving (internal) phase, agitation time (emulsion phase and feed phase), the volume ratio of the membrane phase to the receiving phase, the volume ratio of the external feed phase to the primary water-in-oil emulsion and pH of feed were studied on the percentage extraction of metal ions at 20℃. The results show that it is possible to remove 78% for As(V), 98% for Cd(II), and 99% for Pb(II). Emulsion Liquid Membrane (ELM) is a well-known technique for separating heavy metal ions from wastewater due to the fast extraction and is a single-stage operation of stripping-extraction. The selection of ELM components (Surfactant and Carrier) is a very significant step in its preparation. In the ELM technique, the primary water-in-oil (W/O) emulsion is emulsified to produce water-in-oil-in-water (W/O/W) emulsion. The water in the oil emulsion was prepared by mixing the membrane and internal phases. The extractant D2EHPA (di-2-ethylhexylphosphoric acid) was used as a mobile carrier, Span-80 as a surfactant, and Paraffin as a diluent. Moreover, the internal (receiving) phase was prepared by dissolving sulphuric acid in water. Di-(2-ethylhexyl) phosphoric acid such as surfactant concentration, carrier concentration, sulphuric acid concentration in the receiving (internal) phase, agitation time (emulsion phase and feed phase), the volume ratio of the membrane phase to the receiving phase, the volume ratio of the external feed phase to the primary water-in-oil emulsion and pH of feed were studied on the percentage extraction of metal ions at 20℃. The results show that it is possible to remove 78% for As(V), 98% for Cd(II), and 99% for Pb(II).

• Korean Journal of Optics and Photonics
• /
• v.13 no.1
• /
• pp.15-20
• /
• 2002

We demonstrate a widely-tunable wavelength converter based on four-wave mixing in a semiconductor-fiber ring laser with no external pump light. Applying 10 GHz short pulses at -8 dBm as a probe signal, we achieve continuous wavelength tuning over the semiconductor optical amplifier gain-bandwidth reaching 30 nm down- and 17 m up-wavelength conversion. In addition to the wide tuning capability, the converter shows high-speed conversion and low saturation power capabilities.

• Atmosphere
• /
• v.17 no.1
• /
• pp.69-86
• /
• 2007

The characteristics of the dual-Doppler wind retrieval method based on a three dimensional variational (3DVAR) conception were investigated from the following four points of view; the sensitivity of the number of iteration, the effect of the weak constraint term, the effect of the smoothness term, and the sensitivity of the error mixing ratio of the radial velocities. In the experiment, the radial velocities relative to the Gosan and Jindo radar sites of the Korea Meteorological Administration (KMA) were calculated from the forecasting of the WRF (Weather Research and Forecast; Skamarock, 2004) model at 1330 UTC 30 June 2006, which is the one and half hour forecast from the initial time, 1200 UTC on that day. The results showed that the retrieval performance of the horizontal wind field was robust, but that of the vertical wind was sensitive to the external conditions, such as iteration number and the on/off of the weak constraint term. The sensitivity of error mixing ratio was so large that even the horizontal wind retrieval efficiency was reduced a lot. But the sensitivity of the smooth term was not so large. When we applied this method to the real mesoscale convective system (MCS) between the Gosan and Jindo radar pair at 1430 UTC 30 June 2006, the wind structure of the convective cells in the MCS was consistently retrieved relative to the reflectivity factor structure. By comparing the vertical wind structure of this case with that of 10 minutes after, 1440 UTC 30 June 2006, we got the physical consistency of our method.

• Journal of Conservation Science
• /
• v.35 no.4
• /
• pp.345-361
• /
• 2019

This study demonstrates the application of hyperspectral analysis as a pigment identification method for modern and contemporary Dancheong, the polychrome surface on traditional Korean wooden buildings. In particular, green pigments are the focus of this study. Green pigments in modern and contemporary Dancheong have the largest variation of materials and show a noticeable timeline. Thus, they are most suitable for estimating the manufacture or restoration period of Dancheong. Hyperspectral analysis is a noncontact, long-distance measurement technique that has advantages in the field of Dancheong analysis. It is capable of identifying both organic and inorganic pigments, unlike existing analysis methods. For this experiment, green and other pigments used during the modern and contemporary era were selected and made into painted samples under various mixing conditions that reflect their actual uses. Through hyperspectral analysis, their reflectance characteristics were observed, which enables the derivation of four main features that can distinguish the type of pigments used for color mixture. Based on these, a pigment identification system was designed in the form of a flowchart, and its utility was confirmed through site application. Despite some limitations at this stage, the technique can be complemented by considering proper measurement methods or the continuous accumulation of samples and data. If a database on various materials, mixing ratios, painting techniques, and other external interference factors is developed in future research, it would provide the foundation for a faster and safer analysis environment of Dancheong sites.

• Proceedings of the KSRS Conference
• /
• v.1
• /
• pp.21-24
• /
• 2006

Processes controlling the interannual variation of mixed layer temperature (MLT) averaged over the NINO3 domain ($150-90^{\circ}W$, $5^{\circ}N-5^{\circ}S$) are studied using an ocean data assimilation product that covers the period of 1993 to 2003. Advective tendencies are estimated here as the temperature fluxes through the domain's boundaries, with the boundary temperature referenced to the domain-averaged temperature to remove the dependence on temperature scale. The overall balance is such that surface heat flux opposes the MLT change but horizontal advection and subsurface processes assist the change. The zonal advective tendency is caused primarily by large-scale advection of warm-pool water through the western boundary of the domain. The meridional advective tendency is contributed mostly by Ekman current advecting large-scale temperature anomalies though the southern boundary of the domain. Unlike many previous studies, we explicitly evaluate the subsurface processes that consist of vertical mixing and entrainment. In particular, a rigorous method to estimate entrainment allows an exact budget closure. The vertical mixing across the mixed layer (ML) base has a contribution in phase with the MLT change. The entrainment tendency due to temporal change in ML depth is negligible comparing to other subsurface processes. The entrainment tendency by vertical advection across the ML base is dominated by large-scale changes in wind-driven upwelling and temperature of upwelling water. Tropical instability waves (TIWs) result in smaller-scale vertical advection that warms the domain during La Ni? cooling events. When the advective tendencies are evaluated by spatially averaging the conventional local advective tendencies of temperature, the apparent effects of currents with spatial scales smaller than the domain (such as TIWs) become very important as they redistribute heat within the NINO3 domain. However, such internal redistribution of heat does not represent external processes that control the domain-averaged MLT.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.11a
• /
• pp.673-676
• /
• 2008

Color concrete utilizes peculiar texture and color sense in external appearance actively as a finish. But, this color concrete is essential use of pigment for required color revelation, and color cone cleat from mixing of this pigment are different existent achromatic color concrete and basic properties of matter. this study progressed slump test and setting time examination through mortar injection resistance examination of mortar that mix Pigment.