• Composites Research
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• v.19 no.1
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• pp.36-42
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• 2006

MWNT(multi-walled carbon nanotube)-filled plain-weave glass/epoxy composites were fabricated and electromagnetic characteristics of the composites were investigated. The observation of the microstructures of the composites revealed that MWNTs are mostly distributed in matrix rich region and the interface between glass fiber yarns in warp and fill direction. The permittivity of the composites, measured in X-band (8.2-12.4 GHz) frequency range, increased with weight fraction of MWNTs and remained almost constant with frequency. The measured permittivity was used to investigate the reflection loss of radar absorbing structures (RAS) composed of MWNT-filled composites according to thickness and a RAS were constructed with 10 dB absorbing bandwidth 4.2 GHz and 3.3 mm in thickness.

• Culinary science and hospitality research
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• v.23 no.2
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• pp.56-63
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• 2017

In this study, we evaluated physicochemical properties and sensory characteristics of teriyaki sauce made by using the shell, the byproduct of red snow crab. Moisture content was the highest in fried FRC and the lowest in immersed SOC- while viscosity exhibited contrary tendency. The pH was the highest in dried DRC and the lowest in untreated RAC. Chromaticity was the highest in fried FRC for L, a, and b values altogether. Such result was considered attributable to elution of astaxanthin, a fat-soluble dye protein, which affected chromaticity while it underwent pre-treatment by being fried. Salinity was the highest in fried FRC and lowest in immersed SOC. Available solid contents exhibited contrary tendency. The total free amino acid content was the highest in immersed SOC and the lowest in untreated RAC. Contents of essential amino acids and tasty amino acids, the free amino acids, were the highest in SOC, suggesting that savory taste manifested the most noticeably among specimens treated differently by varying methods. The results of preference test showed that SOC, which showed the highest free amino acid content, also showed the highest preference in terms of outwards appearance, fragrance, taste, texture, and overall items of preference. Those results suggested that the immersion of red snow crab shell increased elution of available solid content and tasty components, influencing the preference of overall taste of teriyaki sauce positively, concerning pre-treatment methods. Based on overall results of the experiment in this study, pre-treatment involving immersion would lead to production of teriyaki with excellent nutrition and sensory features in connection with the use of red snow crab shell for manufacturing teriyaki.

• Korean journal of food and cookery science
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• v.6 no.4 s.13
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• pp.1-8
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• 1990

For the purpose of supplying the imformation to improve the acceptability of soy paste as the condiment, the changes of enzyme activity, general component and flavor compounds (Free amino acid, Nucleic acid related compounds, and peptide) during improved soy paste fermentation were determined. The results were as follows; 1. The protease activity during fermentation were increased continuously, but amylase activity were decreased in 45 day fermentation. Cellulase activity were slowly increased until 45 day, and then slowly decreased. 2. Total nitrogen contents were almost constant during fermentation, but amino nitrogem were increased rapidly. Reducing sugar were not constant, but increased in the end of fermentation. PH were decreased to pH 4.97. 3. Total contents of free amino acid as flavor compound were rapidly increased in 10 day fermentation, but were constant in $30{\sim}60$ day. Aspartic acid contents were increased continuously, but glutamic acid were increased slowly until 30 day fermentation and were almost constant. IMP and GMP contents showed increasing pattern during fermentation.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.4
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• pp.529-538
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• 2002

There is no adverse opinion on the anticariogenic effect of fluoride, so glass ionomer restoration which release the fluoride is recommended fer child patient. To study the anticariogenic effect of initial carious lesion of fluoride released from adjacent glass ionomer restoration, the in situ model was constructed. A microhardness test, polarized scope investigation and electron probe microanalysis was done for analyzing the distribution of fluoride which was precipitated from glass ionomer restoration to the enamel caries lesion. Fuji IX, the conventional glass ionomer, was used for experimental group and Z-100, composite resin that fluoride was not contained, was used for control group. On the microhardness test, the remineralization was accelerated by fluoride. And on the polarized investigation, the size of caries lesion was reduced in the oral cavity and that phenomenon was accelerated by fluoride, too. Electron probe microanalysis shows that the remineralization was accelerated by fluoride and the fluoride concentration on subsurface area was increased. It maybe that the subsurface area was critical to anticariogenic effect. In summary of these result, initial caries lesion can be remineralized in the oral cavity and that phenomenon can be accelerated by fluoride. The subsurface area of caries lesion was a major part of defense to cariogenic invasion and to conserve the subsurface area, the surface of lesion body have to conserved.

• International Journal of Highway Engineering
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• v.8 no.4 s.30
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• pp.1-11
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• 2006

Currently, road mobility improved from the National Road Improvement. Nevertheless delineation system is facility that enhanced driver's safety, that was set up often inconsistent or nonexistent over the road exit ramp So it judged functional investigation will be necessary. This study suggested setting type of the delineation system. That was based on a field study and reviews the legal standard of it and considering driver's cognition behavior. For the study, make a 3D-simulation and so could objectively a comparative test. Comparison variable between delineation setting type is selected conspicuity and visibility. Cased that illustrated characteristics of driver's visual cognition behavior. The experiment was used Eye Marker Recorder for measure the gaze frequency more quantitatively and objectively. And used the ANOVA analysis for significance testing between delineation setting type. A significant percent of the conspicuity analyzed types(Safe mark, Obstacle Sign, Warning Light, and Tubular Maker) in road exit ramp for recognize. And gaze frequency that measure of effectiveness of visibility are measured. On the analysis result, the visibility was significance difference between delineation setting type and visibility of types was best.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.1
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• pp.58-63
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• 2010

The glass-ceramics made from the mixture of coal bottom ash, produced from a thermal power plant mixed with $Na_2O$ and $Li_2O$ was fabricated and their crystallization behavior was studied using a non-isothermal analyzing method. The temperature for 50% crystallization was higher than the exothermic peak temperature $T_p$ at DTA curve and the quickest crystallization temperature was much the same as $T_p$ as identified from the relationships of crystallized fraction and crystallization rate with temperature. By using Kissinger equation describing a crystallization behavior, the activation energy (262 kJ/mol), the Avrami constant (1.7) and the frequency ($5.7{\times}10^{16}/s$) for crystallization were calculated from which the nepheline crystal could be expected as showing an 1~2-dimensional surface crystallization behavior mainly with some bulk crystallization tendency at the same time. The actual observation of microstructure using SEM showed the considerable amount of surface crystals of dendrite and the bulk crystals with low fraction, so the prediction by the Kissinger equation was in accord with the crystallization behavior of glass-ceramics fabricated in this study.

• Culinary science and hospitality research
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• v.16 no.4
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• pp.274-285
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• 2010

This study attempts to develop a mass production product standardized by the application of high pressure extraction cooking(HPEC) in order to suggest a desirable direction for the development of salt contained standardized chicken stock. In our experiment on chicken stock with varying its salt content, the total free amino acid content was highest in S3, which contained 0.3% of salt In addition, when the total content of free amino acid was divided into the contents of essential amino acid, palatable amino acid, and other types of amino acid, they showed the same distribution as the total content of free amino acid. In addition, the total content of palatable amino acid was highest among the specimens. In the results of investigating the palatability of chicken stock according to salt content, saltiness increased with the increase of the salt content, but no significant difference was observed in preference for saltiness. It is believed to have come from the difference in the sensory evaluators' preference for saltiness, and it shows that the salt content has an effect on sweet taste, delicate taste, fishy smell, and color. In particular, specimen 83, which contained 0.3% of salt, showed the highest content of palatable amino acid, and the highest level of delicate taste in sensory tests, suggesting the correlation between palatable amino acid and delicate taste.

• Korean journal of applied entomology
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• v.58 no.1
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• pp.49-54
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• 2019

Clover cyst nematode, Heterodera trifolii are one of the major pests that damage Chinese cabbage in high land cultivation area and have recently been distributed in Korea. This study was conducted to investigate the effect of temperature and inoculation density on the proliferation of clover cyst nematode. The clover cyst nematode was proliferated at $15-30^{\circ}C$ and the egg, female adult and cyst number was the highest at $20^{\circ}C$. As the inoculation density increased, the number of female cyst nematodes increased with the inoculation density and when 16 eggs were inoculated per gram of soil, the amount of growth, number of egg and cyst was the highest. Number of females and eggs were formed more in cabbage than in kale regardless of inoculation density. Chinese cabbage was a favorable host for clover cyst nematode growth than kale.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.249.2-249.2
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• 2010

최근의 고유가와 환경오염에 대한 대응 수단으로 수송용 바이오연료의 보급에 대한 관심이 세계적으로 높아지고 있다. 이 중 바이오디젤은 동식물성 기름으로부터 메탄올과의 전이에스테르화 반응에 의해 생산되는 경유대체 연료로서 환경 친화성과 지속가능성이 인정됨에 따라 그 생산량이 급격히 증가하고 있다. 바이오디젤의 생산량이 증가함에 따라 대두유, 유채유, 팜유 등의 원료유 가격 상승 및 수급 불안정 문제가 대두되고 있으며 식량자원과의 충돌 문제도 발생되고 있다. 이를 해결하기 위한 방안으로 유리지방산 함량이 높은 저가유지 자원(폐식용유, 폐돈지, 폐우지, soapstock, trapped grease)을 이용한 공정 개발 연구가 활발히 진행되고 있다. 본 연구에서는 비활용되고 있는 해외 열대작물 열매씨앗에서 착유한 식물성 오일의 바이오디젤 원료유로서의 사용 가능성을 검토하였다. 열대작물 오일의 물성 분석 결과 고형물, 수분, 인, 유리지방산 함량이 대두원유보다 매우 높게 나타났다. 오일 중의 인지질은 바이오디젤 제조 반응후 에스테르와 글리세린의 층분리를 방해하여 공정 효율을 감소시키고 유리지방산은 염기촉매와 결합하여 지방산염을 생성해 생산수율을 감소시키는 문제를 일으킨다. 고형물과 수분은 여과와 감압증발에 의해 쉽게 제거가 가능하였다. 15~20%의 유리지방산 함유 열대작물 오일의 전처리를 위해 균질계 산촉매와 비균질 고체 산촉매를 이용해 에스테르화 반응 효율을 조사한 결과 황산이 가장 높은 효율을 보였다. 반응표면분석법(Response Surface Method, RSM)을 적용해 메탄올과 촉매량의 2변수 에스테르화반응 최적화를 수행한 결과 메탄올 26%, 촉매 0.98%로 최적 조건이 도출되었으며 초기 산가 33mgKOH/g에서 0.98mgKOH/g으로 감소됨을 확인하였다. 전처리 정제한 오일의 물성분석 결과 고형물 0.1%, 수분 0.10%, 산가 1.0mgKOH/g, 인함량 20ppm 이하로 바람직한 원료유가 생산됨을 알 수 있었다. 제조된 원료유를 이용해 전이에스테르화 반응 최적화 실험을 RSM에 근거하여 진행한 결과 KOH 0.8%, 메탄올:오일 몰비 6.2:1, 반응온도 $60^{\circ}C$, 교반속도 200rpm, 반응시간 30분으로 나타났으며 증류 정제전 97.3%, 증류후 100.0%의 바이오디젤을 생산 할 수 있었다. 열대작물 오일의 전처리 공정은 메탄올을 과잉양으로 사용함으로 효과적인 알콜 회수 공정이 중요하다. 전처리 후 층분리를 통해 회수되는 메탄올 중의 수분함량은 2%~7%로서 이를 전처리 반응에 재사용하기 위해서는 0.3%이하의 수분함량으로 정제가 필요하다. 본 연구에서는 고가의 증류탑 형태가 아닌 단증류방식으로 2단계 내지 3단계로 0.3% 수분의 메탄올 회수 조건을 도출하였으며 파일롯 공정 설계를 진행하고 있다. 이로서 본 연구의 열대작물 오일은 저가로 충분한 물량의 확보가 가능하다면 바이오디젤 원료 자원으로서 큰 활용가치가 있는 것으로 판단된다.

• Journal of the Korean Ceramic Society
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• v.41 no.12 s.271
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• pp.915-920
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• 2004

The main phase of $BaTi_{4}O_9$-based ceramics was transformed to $BaTi_{5}O_{11}$ caused by the sintering with borosilicate glass, which was analyzed by using XRD and TEM. We considered that the phase change from $BaTi_{4}O_9$-based ceramics to the Ti-rich $BaTi_{5}O_{11}$ phase resulted from borosilicate glass selective absorbing of Ba ions from the $BaTi_{4}O_9$. In these results, we found a dependence on the amounts of the glass frits and the annealing temperature, and the phase change is also dependent of the main phases of $Ba_{4}Ti_{13}O_{30},\;and\;Ba_{2}Ti_{9}O_{20}$, which are involved in the $BaO-TiO_2-based$ Ti-rich region. In the case of sintering of middle- and high- permittivity material with additional glass frits for middle- and high- dielectric coefficients LTCC composition, control of weight fraction of the glass frits accompanying low-temperature sintering property with appropriate phase change is required.