• ALGAE
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• 제19권1호
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• pp.1-6
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• 2004

Carbon ($^{14}CO_2$) and nitrogen ($^{15}NH_4$ and $^{15}NO_3$) uptake were measured at two stations in the hypertrophic zone of the Seonakdong River, where Microcystis aeruginosa explosively bloomed in September 1998. Significant nitrogen limitation occurred in the period of Microcystis bloom, while phosphorus limitation was common in the river. The specific nitrogen ($NH_4$ + $NO_3$) uptake was 12-50 $\mu$mol mg chl-a$^{-1}$ hr$^{-1}$ at two stations, showing substantially higher than for any other freshwaters. The specific nirtogen uptake was higher at the GAR Station of the nitrogen-limited area and this high nirtogen uptake resulted in low $^{14}C:^{15}N$ atomic ratios of algal uptake. Carbon uptake was dependent upon irradiance, decreasing gradually toward the bottom in the euphotic zone, whereas the nitrogen uptake increased slightly toward the bottom. $NH_4$ preferable uptake against $NO_3$ was hardly discemilble due to the fact that it exceeded the $NH_4$ ambient concentraiton. The $^{14}C:^{15}N$ atomic ratios of algal uptake in the surface waters approached the Redfield C:N ratio.

• Nuclear Engineering and Technology
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• 제54권1호
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• pp.269-274
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• 2022

An artificial neural network (ANN) that identifies radionuclides from low-count gamma spectra of a NaI scintillator is proposed. The ANN was trained and tested using simulated spectra. 14 target nuclides were considered corresponding to the requisite radionuclide library of a radionuclide identification device mentioned in IEC 62327-2017. The network shows an average identification accuracy of 98.63% on the validation dataset, with the gross counts in each spectrum N_c = 100~10000 and the signal to noise ratio SNR = 0.05-1. Most of the false predictions come from nuclides with low branching ratio and/or similar decay energies. If the N_c>1000 and SNR>0.3, which is defined as the minimum identifiable condition, the averaged identification accuracy is 99.87%. Even when the source and the detector are covered with lead bricks and the response function of the detector thus varies, the ANN which was trained using non-shielding spectra still shows high accuracy as long as the minimum identifiable condition is satisfied. Among all the considered nuclides, only the identification accuracy of ²³⁵U is seriously affected by the shielding. Identification of other nuclides shows high accuracy even the shielding condition is changed, which indicates that the ANN has good generalization performance.

• 생명과학회지
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• 제23권8호
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• pp.1004-1009
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• 2013

기능성식품 또는 첨가제로의 적용가능성을 확인하기 위하여 6 종 해조류의 생화학적 조성 및 영양학적 가치를 분석하였다. 갈조류(미역, 톳, 다시마), 홍조류(김, 꼬시래기) 및 녹조류(파래) 등 해조류의 생화학적 조성(수분, 회분, 단백질, 지질 및 식이섬유)과 지방산 함량이 분석되었다. 수분함량은 11.47-13.94%, 회분은 19.15-26.50%, 단백질은 5.08-15.44%, 지질은 2.75-4.43% 및 식이섬유는 36.84% to 52.98%로 나타났다. 주요지방산은 C14:0, C16:0, C18:0, C16:1, C18:1n-3, C18:2n-6, C18:3n-6, C20:4n-6 및 C20:5n-3이었다. 흥미롭게도 분석된 해조류에서 docosahexaenoic acid (C22:6n-3, DHA)는 검출되지 않았거나 미량 검출되었다. n-3 지방산 함량은 다른 PUFA에 비해 높았으며, n-6/n-3 비율은 매우 낮았다. 이러한 결과는 우리나라 연안에서 서식하고 있는 해조류가 인간 건강에 유익할 수 있음을 의미한다.

• 한국축산식품학회지
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• 제36권5호
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• pp.679-688
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• 2016

The aim of this research was to evaluate: 1) the fatty acid profile of ten muscles from high marbled (HM, quality grade 1⁺⁺) and low marbled (LM, quality grade 2) Hanwoo carcass, 2) the relationship between the fatty acid profile and sensory traits. There were significant (p<0.001) differences in fat content and fatty acid composition among the 10 muscles obtained from HM and LM Hanwoo steers. The proportions of SFA (saturated fatty acid), MUFA (monounsaturated fatty acid) and PUFA (polyunsaturated fatty acid) were significantly (p<0.001) different among the 10 muscles due to differences in all fatty acids except eicosapentaenoic acid (EPA, C20:5n-3). The high-fat muscles had a lower n-6/n-3 ratio compared to the low-fat muscles (p<0.001). LM muscles had a significantly (p<0.05) higher proportion of SFA than HM muscles due to a higher proportion of stearic acid (C18:0). On the contrary, HM muscles had a significantly (p<0.01) higher proportion of MUFA than LM muscles due to higher oleic acid (C18:1n-9) proportion. SFA had a significant correlation with CIE a* (r=0.281; p<0.01) and drip loss (%) (r=−0.233; p<0.001). Cooking loss (%) had a significantly (p<0.05) negative correlation with PUFA (r=−0.233; p<0.05). Overall palatability was positively correlated with SFA (r=0.262; p<0.01), but negatively correlated with PUFA (r=−0.567; p<0.001). There was no significant correlation between oleic acid and any of the sensory traits (p>0.05).

• 센서학회지
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• 제13권4호
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• pp.303-308
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• 2004

This paper descibes on the characteristics of Ta-N(tantalum nitride) ceramic thin-film strain gauges which were deposited on Si substrates by DC reactive magnetron sputtering in an argon-nitrogen atmosphere (Ar-$(4{\sim}16%)N_{2}$) for high-temperature applications. These films were annealed in $2{\times}10^{-6}$ Torr vacuum furnace at the range of $500{\sim}1000^{\circ}C$. Optimum deposition atmosphere and annealing temperature were determined at $900^{\circ}C$ for 1 hr. in 8% $N_{2}$ gas flow ratio. Under optimum formation conditions, the Ta-N thin-film for strain gauges was obtained a high-resistivity of $768.93{\mu}{\Omega}{\cdot}cm$, a low temperature coefficient of resistance (TCR) of -84 ppm/$^{\circ}C$ and a good longitudinal gauge factor (GF) of 4.12.

• 전자공학회논문지C
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• 제34C권12호
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• pp.20-27
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• 1997

In this paper, a multiplying digital-to-analog converter (MDAC) circuit for low-power high-resolution CMOS algorithmic A/D converters (ADC's) is proposed. The proposed MDAC is designed to operte properly at a supply at a supply voltge between 3 V and 5 V and employs an analog0domain power reduction technique based on a bias switching circuit so that the total power consumption can be optimized. As metal-to-metal capacitors are implemented as frequency compensation capacitors, opamps' performance can be varied by imperfect process control. The MDAC minimizes the effects by the circuit performance variations with on-chip tuning circuits. The proposed low-power MDAC is implementd as a sub-block of a 10-bit 200kHz algorithmic ADC using a 0.6 um single-poly double-metal n-well CMOS technology. With the power-reduction technique enabled, the power consumption of the experimental ADC is reduced from 11mW to 7mW at a 3.3V supply voltage and the power reduction ratio of 36% is achieved.

• 한국세라믹학회지
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• 제31권4호
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• pp.381-388
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• 1994

A new process which co-fires the low-firing-substrate and copper conductor was studied to achieve good bond strength and low sheet resistance of conductor. Cupric oxide is used as the precursor of conductive material in the new method and the firing atmosphere of the new process is changed sequently in air H2N2. The addition of cupric oxide and variations of firing atmosphere permited complete binder-burnout in comparison with the conventional method and contributed to the improvement of resistance and bonding behaviors. The potimum conditions of this experiment to obtain the satisfactory resistance and bond strength are as follows (binder-burnout temperature in air; 55$0^{\circ}C$, reducing temperature in H2; 40$0^{\circ}C$ for 30 min, ratio of copper and cupric oxide; 60:40~30:70 wt%). The bonding mechanism between the substrate and metal was explained by metal diffusion layer in the interface and the bond strength mainly depended on the stress caused by the difference of shrinkage and thermal expansion coefficient between the substrate and metal.

• 한국잠사곤충학회지
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• 11호
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• pp.63-68
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• 1970

가잠의 Virus다각체의 저온 및 고온처리에 대한 유발현상을 조사하기 위하여 5령기잠을 공시하고 저온(5$^{\circ}C$, 24hrs.), 고온(Hot water bath 에 4$0^{\circ}C$, 5min으로 침지 및 Oven 내에 4$0^{\circ}C$, 30min.으로 단독 및 복합처리하여 핵다각체병(N) 중장형 다각체병(C), 병발형(NC) 유발률을 조사하고 동시에 핵다각체병(N)과 중장형다각체병(C)대하여 Giemsa solution 염색법에 의한 염색성을 조사하였다. 1. 냉장(5$^{\circ}C$, 24 시간) 처리와 고온(Hot water bath, 4$0^{\circ}C$, 5분간) 처리를 한 핵복다각체병(N)은 중장형다각체병(C)보다 그 유발률이 적고 또 복합처리에 있어서도 중장형다각테병(C)의 유발율은 핵다각체병(N)보다 많다. 2. 냉장처리후 고온(4$0^{\circ}C$, 30분간 건열) 처리, 반대로 고온처리후 냉장처리한 Virus다각체의 유발률도 중장형다각체병(C) 보다 핵형다각예병(N)의 유발현상이 현저하게 많이 나타났다. 3. Giemsa solution 염색법에 의한 핵다각체병(N)의 다각체는 염색이 되지 않으나 중장형다각예병(C)의 다각체는 잘 염색되어 염색성에 의하여 구별할 수 있었다.

• 한국지반환경공학회 논문집
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• 제25권6호
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• pp.5-12
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• 2024

현재 저수지 제체의 차수성 및 안전성 확보를 위해 약액을 저압으로 주입하여 제체 손상을 최소화하는 그라우팅 공법이 보편적으로 사용되고 있으나, 내구성 확보와 체계적인 고화재의 배합비 결정방법이 정립되어 있지 않은 문제들이 있다. 본 연구에서는 원지반과 고화재를 다양한 중량비율로 교반·혼합하였을 경우 혼합체의 투수계수와 강도를 실내시험을 통해 확인하였으며, 시험결과들의 분석을 통해 최적 배합비를 제안하였다. 실내실험을 위한 공시체는 고화재의 배합량을 고려하여 제작하였다. 투수시험용 공시체는 사질토와 점성토 별 고화재 배합량 1.5kN/m³에 대해 제작하였으며, 투수시험 결과 차수 성능이 확보되어 각종 설계기준을 만족하는 것을 확인하였다. 강도시험을 위한 공시체는 점성토의 경우 5가지, 사질토는 3가지 배합비로 각각 3개 총 24개의 시편을 제작하였으며, 시험 결과 사질토와 점성토 모두 배합량 2.0kN/m³ 이하에서는 일축압축강도가 재령일이 증가함에 따라 선형적으로 증가하는 경향을 나타냈다. 따라서 현장에 적용되는 최적의 배합비는 고화재 배합량을 1.5kN/m³ 및 2.0kN/m³으로 결정하였다. 또한 현재 운영 중인 노후 저수지 개보수사업 설계사례를 대상으로 실험성과를 반영한 수치해석을 실시한 결과 저수지 제체의 차수 및 안전성 증대 효과를 확인하였다.

• Journal of Periodontal and Implant Science
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• 제50권3호
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• pp.135-145
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• 2020

Purpose: The aim of this study was to evaluate the serum levels of oxidized low-density lipoprotein (oxLDL), anti-oxLDL, and myeloperoxidase (MPO) in hyperlipidemic patients with periodontal disease. Methods: This study included 123 patients with hyperlipidemia categorized based on metabolic control as mild to moderate (H1) (n=66) or poor (H2) (n=57), as well as systemically healthy controls (C) (n=68). Serum levels of lipids, oxLDL, anti-oxLDL, and MPO were evaluated, along with clinical periodontal parameters. Results: The percentage of bleeding on probing (BOP%) and the clinical attachment level were significantly higher in the H2 group than in the C group. Patients with hyperlipidemia had a relatively high risk of developing periodontal disease. The oxLDL and anti-oxLDL levels were higher in H2 patients with periodontitis than in the control or H1 patients with periodontitis. In the H1 and H2 groups, the ratio of total cholesterol to high-density lipoprotein was significantly correlated with gingival index, BOP%, and oxLDL levels. Conclusions: Our findings indicate that the lipoprotein-associated inflammatory mediators of oxLDL, anti-oxLDL, and MPO may play an important role in the relationship between periodontal disease and hyperlipidemia.