• Journal of the Korean Chemical Society
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• v.67 no.6
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• pp.420-428
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• 2023

Crosslinking was introduced into vinylized-mesoporous silica and recycled polyethylene. By introducing a vinyl group into the mesoporous silica, it becomes a material capable of inducing cross-linking with non-polar polyethylene. By synthesizing vinylized-mesoporous silica and inducing crosslinking with recycled polyethylene, a recycled polyethylene composite with improved physical properties than existing recycled polyethylene was synthesized. In addition, even when a small amount is added according to the grade of recycled polyethylene using vinylized-mesoporous silica, the crosslinking reaction proceeds and all physical properties are improved. Four types of vinylized-mesoporous silica were synthesized, and the shape, microstructure, and functional groups were analyzed by TEM, BET, FT-IR, and XRD. Using vinylized-mesoporous silica, three types of compounds were blended by crosslinking reaction with recycled polyethylene. In order to confirm the presence or absence of crosslinking, analysis was performed using XPS and FT-IR, and physical properties such as tensile strength, elongation, flexural strength, and flexural modulus were confirmed using a universal testing machine. As a result, by applying vinylized-mesoporous silica to recycled polyethylene in various grades, the weak physical properties of existing recycled polyethylene were overcome. By applying the vinylized-mesoporous silica, recycled polyethylene composite material that overcomes the weak physical properties to the normal polyethylene, it shows the optimal physical property index that can be used commercially. Therefore, it is expected that it can potentially increase the use of recycled polyethylene and recycle resources.

• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.5
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• pp.363-369
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• 2016

Enhancing mechanical strength of concrete has been fascinated using carbon-based nanomaterials such as CNT and graphene. The key to improving strength is a dispersion of nanomaterials. A novel method is required to investigate the dispersion inner concrete nondestructively. In this study, the optical optical properties such as refractive index and absorption coefficient are measured in nano-cement mortar specimens containing MWCNT and GO using THz electro-magnetic waves. From the results, the properties of nano-cement mortar are confirmed to be 1.0% to 2.5% higher in refractive index, and -14% to 28% higher in absorption coefficient than those of cement mortar at the average values. Using these characteristics, visualizing the dispersion of nano-concrete structures seems possible in future.

• Journal of the Korean Chemical Society
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• v.46 no.3
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• pp.233-240
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• 2002

In this work, the cure kinetics and rheological and mechanical properties of diglycidylether of bispheonol A (DGEBA, EP)/polyurethane (PU) blends were investigated. The 1 wt% N-benzylpyrazinium hexafluoroantiminate (BPH) was used as a latent thermal catalyst. Latent properties were performed by measurement of the conversion as a function of reaction temperature using DSC. And the rheological properties of the blend systems were investigated under isothermal conditions using a rheometer. Crosslinking activating energies (Ec) were also determined from the Arrhenius equation based on gel time and curing temperature. The impact strengths were measured as mechanical properties of the casting specimens. The BPH in the blend systems could be an excellent latent thermal catalyst without any co-initiator. The rheological results showed that Ec was highest when PU content was 30 wt% which was in good agreement with the impact strengths. This was probably due to the intermolecular hydrogen bonding between the hydroxyl group in PU and EP, resulting in increasing the crosslinking density.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.880-883
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• 2009

석탄가스화복합발전(IGCC) 시스템에서 합성가스 중에 포함된 황화수소($H_2S$)는 후단의 가스 터빈과 같은 장치의 부식을 방지하고, 합성가스를 이용하는 연료전지 등의 연계 공정에서 요구하는 수준에 맞추어 정제되어야 한다. 본 연구에서는 $H_2S$ 정제공정 추가에 따른 IGCC 시스템의 효율저하를 최소화하기 위하여 고온고압에서 사용가능한 탈황제를 분무건조법을 이용하여 제조하고 제조된 탈황제에 대해 물성 및 황 흡수능 시험을 실시하였다. 형상, 내마모도, 평균입자크기, 충진밀도와 함께 제조된 탈황제가 적용되는 유동층 공정에 적합한 강도를 보유하는지 여부를 미국표준시험방법에 의하여 측정하였다. 황 흡수능은 열중량분석기를 반응기로 사용하여 모사 합성 가스 분위기에서 측정하였다. 분무건조 성형된 탈황제의 일부가 구형이 아닌 타원형 또는 도넛 형태를 나타내고 있어 형상 개선을 위한 제조방법 개선이 필요한 것으로 나타났다. 제조된 탈황제는 기공도가 65% 이상으로 macropore가 기공부피의 대부분을, mesopore가 비표면적의 대부분을 제공하고 있었다. 소성온도를 650 $^{\circ}C$에서 750 $^{\circ}C$로 증가시킴에 따라 대체로 강도가 감소하는 경향을 나타내었다. 열중량분석기로 측정된 황 흡수능은 약 10 wt%로 나타났다. 제조된 탈황제 중 일부는 유동층 공정에 적합한 물성을 보유하고 있었으며 반응성 또한 기존에 개발된 탈황제에 버금가는 성능을 나타내어 향후 공정 적용이 가능할 것으로 분석되었다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.5
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• pp.657-664
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• 2013

By using shear mixing and ultrasonication, we fabricated specimens of well-dispersed multi-walled carbon nanotube composites. To confirm the proper dispersion of the filler, we used scanning electron microscopy images for quantitative evaluation and a tensile test for qualitative assessment. Furthermore, the coefficients of thermal expansion of several specimens having different filler contents were calculated from the measured thermal strains and temperatures of the specimens. Based on the microscopy images of the well-dispersed fillers and the small deviations in the measurements of the tensile strength and stiffness, we confirmed the proper dispersion of nanotubes in the epoxy. As the filler contents were increased, the values of tensile strength increased from 58.33 to 68.81 MPa, and those of stiffness increased from 2.93 to 3.27 GPa. At the same time, the coefficients of thermal expansion decreased. This implies better thermal stability of the specimen.

• Food Science of Animal Resources
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• v.24 no.1
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• pp.73-79
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• 2004

Functional properties of farm-grown pheasant meat with different sex, age and cutting portion were investigated, and the textural and sensory characteristics of processed products were also evaluated. Chemical composition of pheasant meat was characterized to be high in protein and low in fat, and breast muscle showed more protein and less moisture than thigh muscle. Moisture/protein ratio of the pheasant meat was relatively low in a range of 2.82∼3.40, indicating the pheasant meat would be a good source of processed meat, and it had high water holding capacity and myofibrillar protein extractability with some variations depending on age and portion cut(p<0.05). Thigh muscle showed higher value of L＊ and b＊ and lower value of a＊ than breast muscle. However, no difference was observed in color of meat with different age and sex. The meat from the 6 months and the breast cut had lower shear force than those of respective 17 months and the thigh regardless of sex. The pressed ham and sausage manufactured with the pheasant meat had better score than the commercial products manufactured with pork or chicken in sensory and textural parameters.

• Science of Emotion and Sensibility
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• v.17 no.1
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• pp.93-104
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• 2014

This paper investigates the physical properties such as water absorption, drying and hygral expansion of moisture responded transformable fibers and their knitted fabrics including dyeing characteristics according to the different dyeing time and temperature. For this purpose, three kinds of covered filament yarn specimens using HEF and spandex as core and PET, aerocool as a covering filament were prepared. The knitted fabric specimens were made using three kinds yarn specimens and dyed with different dyeing temperature and time. The moisture absorption, drying and hygral expansion of three kinds of knitted fabric specimens were measured and discussed with yarn structure. The wearing performance of these knitted fabric specimens were also measured and discussed with yarn characteristics using FAST system. Finally, the dyeing characteristics such as dye affinity, color difference and color fastness to washing of these knitted fabric specimens were measured and discussed with different dyeing temperature and time for examining dyeing process performance of these moisture responded transformable knitted fabrics.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.5
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• pp.254-259
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• 2012

The mechanical property enhancement was studied using fly ash produced from fluidized bed type boiler in power plant, which contains a lot of Ca component being used to carbonate for $CO_2$ fixation in the lightweight aggregates made of cement and some portion of fly ash as a cement substitution under the supercritical condition. Specimens having various fly ash substitution rates and curing periods were carbonated under the supercritical condition at $40^{\circ}C$. The weight change rate, carbonation rate by TG/DTA analysis, 1% Phenolphthalein test, specific gravity and mechanical compression strength test were performed to observe the mechanical property enhancement of the cemented materials after carbonation under the supercritical condition and to make sure those could be classified as lightweight aggregates having specific gravity under 2.0.

• Current Research on Agriculture and Life Sciences
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• v.32 no.2
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• pp.85-89
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• 2014

This study uses turbidity and rheological measurements to examine the effects of the molecular weight (MW), substitution type and substitution degree of cellulose ether and water content on the cooking characteristics of rice noodles, the turbidity of the cooking solution, and the compression strength of the cooked noodles. When increasing the MW of cellulose ether and water content, the turbidity decreased, thereby improving the morphological stability of the rice noodles during cooking. Thus, when controlling the above factors effectively, the rice noodle cooking solution had a lower turbidity than with wheat noodles. Measuring the compression strength of the rice noodles using a rheometer was also effective for examining the pasting characteristics of the rice noodles and texture changes during cooking. As a result, the water content and MW of cellulose ether were found to affect the pasting characteristics and texture of the rice noodles more than the other factors examined.

• Applied Biological Chemistry
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• v.41 no.2
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• pp.166-174
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• 1998

The effects of some organic acids on the shelf life of cooked noodle and the change in textural properties were studied. Organic acids used were vinegar, lactic, citric and malic acid. The pH of noodle was adjusted to $4.7{\pm}0.25$ by dipping it in each solution for 30 seconds. Total microbial count and turbidity of the treated samples were measured storage for 4 days at $15^{\circ}C$. The total count was high in order of control, malic, citric, lactic acid and vinegar. High turbidity was observed in order of control, lactic, malic, citric acid and vinegar. Hardness, adhesiveness, cohesivenes and springiness were measured for 30 days at $35^{\circ}C$ using Rheometer along with concurrent sensory evaluation. The acid treated samples showed higher values in hardness and cohesiveness than control but lower in adhesiveness and springiness. After 30 days storage, the malic or citric acid treated sample led to a somewhat higher gumminess than control. Based on the sensory evaluation the malic acid treated noodle significantly exhibited the highest score followed by citric, lactic acid, control and vinegar.