• 한국재료학회지
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• 제34권3호
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• pp.138-143
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• 2024

Ni-CNT nanocomposites were synthesized via the electrical explosion of wire (EEW) in acetone and deionized (DI) water liquid conditions with different CNT compositions. The change in the shape and properties of the Ni-CNT nanopowders were determined based on the type of fluids and CNT compositions. In every case, the Ni nanopowder had a spherical shape and the CNT powder had a tube shape. However, the Ni-CNT nanopowders obtained in DI water exhibited irregular shapes due to the oxidation of Ni. Phase analysis also revealed the existence of nickel oxide when using DI water, as well as some unknown peaks with acetone, which may form due to the metastable phase of Ni. Magnetic properties were investigated using a Vibrating Sample Magnetometer (VSM) for all cases. Nanopowders prepared in DI water conditions had better magnetic properties than those in acetone, as evidenced by the simultaneous formation of super paramagnetic NiO peaks and ferromagnetic Ni peaks. The DI water (Ni:CNT = 1:0.3) sample revealed better magnetic results than the DI water (Ni-CNT = 1:0.5) because it had less CNT contents.

• 한국염색가공학회지
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• 제30권4호
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• pp.256-263
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• 2018

The binder polymers for digital textile printing(DTP) pigment inks were prepared using miniemulsion polymerization with various monomer compositions to study effects of monomer compositions on particle size distribution, average molecular weight, Tg, and color strength and rubbing fastness of the dyed fabrics with the prepared binder based pigment ink. The monomers used were MMA(Methyl methacrylate), BA(Butyl acrylate), MAA(Methacrylic acid), NMA(N-methylol acrylamide), NEA(N-ethylol acrylamide) and the ratios of the monomers were changed. The particle size was the smallest with 136nm when the MMA to BA weight ratio was 4:16 and the largest with 290nm when the MMA, BA, MAA, NEA ratio was 2.5:17:0.25:0.25. However, the glass transition temperature was lowest with $-41.90^{\circ}C$ and the color strength and rubbing fastness of the resulting sample were the best when the MMA, BA, MAA, NEA ratio was used. This suggested that the introduction of the NEA monomer to the binder polymer for the pigment ink could be an efficient way to enhance the rubbing fastness of the DTP pigment inks present.

• 한국식품과학회지
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• 제27권5호
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• pp.724-728
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• 1995

건조된 털목이버섯의 일반성분, 무기질, 아미노산함량을 분석하였으며, 또한 건조된 털목이버섯을 수화과정시 복원력, 갈색도 및 침지후 핵산관련물질의 함량 변화 등을 조사한 결과는 다음과 같다. 일반성분조성은 조단백질 12.6%, 조지방 2.1%, 조섬유 6.7%, 그리고 조회분 6.2%였다. 목이버섯의 Ca, K, Mg 함량은 다른 무기물에 비해서 높았으나 Mn, Ni 함량은 매우 적었다. 그리고 아미노산중 aspartic acid, glutamic acid의 함량이 가장 높았다. 수화과정시 침지시간 및 온도의 증가와 함께 가용성물질의 용출율, pH, 갈색도 및 복원력은 증가하였고, 침지후 핵산관련물질의 함량은 감소하였다. $5^{\prime}-GMP$가 가장 높은 함량을 보였으며, 가장 적은 성분은 $5^{\prime}-CMP$였다.

• 한국재료학회지
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• 제21권8호
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• pp.456-460
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• 2011

Microelectromechanical systems (MEMS)-fabricated suspended devices were used to measure the in-plane electrical conductivity, Seebeck coefficient, and thermal conductivity of 304 nm and 516 nm thick InGaAlAs films with 0.3% ErAs nanoparticle inclusions by volume. The suspended device allows comprehensive thermoelectric property measurements from a single thin film or nanowire sample. Both thin film samples have identical material compositions and the sole difference is in the sample thickness. The measured Seebeck coefficient, electrical conductivity, and thermal conductivity were all larger in magnitude for the thicker sample. While the relative change in values was dependent on the temperature, the thermal conductivity demonstrated the largest decrease for the thinner sample in the measurement temperature range of 325 K to 425 K. This could be a result of the increased phonon scattering due to the surface defects and included ErAs nanoparticles. Similar to the results from other material systems, the combination of the measured data resulted in higher values of the thermoelectric figure of merit (ZT) for the thinner sample; this result supports the theory that the reduced dimensionality, such as in twodimensional thin films or one-dimensional nanowires, can enhance the thermoelectric figure of merit compared with bulk threedimensional materials. The results strengthen and provide a possible direction in locating and optimizing thermoelectric materials for energy applications.

• 한국수산과학회지
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• 제51권1호
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• pp.79-90
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• 2018

Fish ages are critical information in fish stock assessments because they are required for age-structure models such as virtual population analysis and stochastic catch-at-age models, whose outputs include recruitment strengths, a spawning stock size (abundance or biomass), and the projection of a fish population size in future. However, most countries other than the developed countries have not identified ages of fish caught by fisheries or surveys in a consistent manner for a long time (e.g.,>20 years). Instead, data about fish body sizes (e.g., lengths) have been well available because of ease of measurement. To infer age compositions of fish in a target group using fish length data, we intended to improve the length frequency analysis (LFA), which Schnute and Fournier had introduced in 1980. Our study was different in two ways from the Schnute and Fournier's method. First we calculated not only point estimates of age compositions but also the uncertainty in those estimates. Second, we modified LFA based on the von Bertalanffy growth model (vB-based model) to allow both individual-to-individual and cohort-to-cohort variability in estimates of parameters in the vB-based model. For illustration, we used data about lengths of Korean mackerel Scomber japonicas caught by purse-seine fisheries from 2000-2016.

• Journal of Electrochemical Science and Technology
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• 제11권3호
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• pp.238-247
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• 2020

Some nano structured bimetallic NiPd electrocatalysts were electrodeposited on glassy carbon electrodes using a double potential step chronoamperometry. The morphology of the electrodeposited samples was investigated by field emission-scanning electron microscopy, while their compositions were evaluated using energy dispersive X-ray spectroscopy. It was observed that the electrodeposited samples contained a low Ni content, in the range of 0.80 - 7.10%. The electrodeposited samples were employed as the anode electro-catalysts for the oxidation of sodium borohydride in NaOH solution (1.0 M) using cyclic voltammetry, chronoamperometry, rotating disk electrode, and impedance spectroscopy. The number of exchanged electrons, charge transfer resistances, apparent rate constants, and double layer capacitances were calculated for the oxidation of borohydride on the prepared catalysts. According to the results obtained, the NiPd-2 sample with the lowest Ni content (0.80%), presented the highest catalytic activity for borohydride oxidation compared with the other NiPd samples as well as the pure Pd sample. The anodic peak current density was obtained to be about 1.3 times higher on the NiPd-2 sample compared with that for the Pd sample.

• 한국식품영양과학회지
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• 제30권2호
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• pp.199-203
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• 2001

Chopi, Zanthaxylum piperitum DC., has been used as natural spice traditionally in the Far East countries including Korea. This study was performed with the object of providing basic data, firstly for the decision of the appropriate harvesting time for traditional use of chopi and secondly for developing a new spice satisfying the national dietary custom from chopi as raw material. Concerning the conte수 and its change of the proximate composition, the content of moisture and crude protein decreased in all sample, while the content of fiber and ash tended to increased with the lapse of harvest time. The content of mineral elements tended to increase in every sample with the lapse of harvest time, and contents of K and P were higher than that of Ca, Na and Mg. Every sample showed the highest content of 15~16 components of total amino acids at the first period and the content decreased gradually with the lapse of harvest time. On the basis of the first period, every sample showed the highest content of aspartic acid, the lowest content of methionine and the trace of cysteine. Free amino acids increased considerably with the lapse of harvest time for peels of chopi and minchopi broth, while the amount for leaves increased on the contrary.

• 한국식품저장유통학회지
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• 제13권6호
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• pp.703-707
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• 2006

본 연구는 각종 기능성을 함유하고 있는 차조기의 소비 증대와 부가가치 증대를 위하여 채취 시기별 차조기의 성분변화를 조사하였다. 수확 시기는 2005년 7월14일에서 2005년 9월2일 까지 총4회(I, II, III, IV)로 나누어 일반성분, 중금 속, 무기질, 아미노산, perillaldehyde, anthocyanin 성분을 분석하였다. 환원당의 함량은 수확시기에 따라 계속 증가하였으나 조단백질, 조지질, 총 아미노산 함량은 III차(8월15일) 채취시기 이후 급격히 감소하였다. 중금속(As, Pb, Cd, Hg)은 모든 처리구에서 감지되지 않았다. 무기질은 Zd, Fe, Mg는 III차 수확시기 이후 감소하였으나, Ca, K, P 함량은 수확시기에 따라 큰 차이를 나타내지 않았다. Perilladehyde는 I 차 0.36% II차 0.42%, III차 0.45%, IV차 0.35%를 각각 나타냈다. Anthocyanin는 함량은 I차 0.53%, II차 1.15%, III차 1.21%, IV차 0.87%를 나타냈다.

• 한국식품위생안전성학회지
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• 제12권2호
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• pp.111-116
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• 1997

For the purpose of improving hygienic quality of dried-Angelica Keiskei Koidz powder, the effect of ozone treatment and gamma irradiation on the microbial decontamination and physicochemical properties were investigated. Gamma irradiation at 5 to 7.5 kGy resulted in sterilizing total aerobic bacteria, molds and coliforms below detective levels, while ozone treatment for 8 hours up to 18 ppm did not sufficiently eliminate the total aerobic bacteria of the sample. The physicochemical properties of the sample were not changed by gamma irradiation up to 7.5 kGy, whereas, ozone treatment caused remarkable changes in pH, TBA value, chlorophyll, carotenoid and fatty acid compositions. Therefore, this investigation demonstrated conclusively that gamma irradiation was more effective than ozone treatment for decontaminating and sterilizing the dried-Angelica Keiskei Koidz powder, with minimal effect on the physicochemical properties analyzed.

• Elastomers and Composites
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• 제51권1호
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• pp.38-42
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• 2016

For improving the heat loss of a refrigerator around door gasket, it is very important to reduce the amount of rubber magnet used, of which thermal conductivity is much higher than the plastics, and enhancing the magnetic properties of rubber magnet itself is crucial for this. In the present study, therefore, a relationship between the optimum conditions of rubber magnet fabrication process and raw material compositions in the ferrite powder/CPE binder compounds was investigated for finding a way to enhance the magnetic properties of rubber magnet. Magnetic attraction forces of a sample rubber magnet was measured as function of distance, and thermal properties of the sample ferrite powder/CPE binder compound were analyzed with TG/DTA thermal analyzer. As a results, a rubber magnet strip with enhanced magnetic properties was expected to be fabricated, of which raw material compound was prepared by compounding with higher ferrite magnetic powder concentration.