• 한국태양에너지학회 논문집
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• 제30권5호
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• pp.107-114
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• 2010

Understanding of reflectance of solar concentrators is important for assessing concentration performance. However inaccurate data about refractive indices of constituent materials and dust accumulation on the surface often prevent figuring out reflectance variations. The current study proposes an approach calculating concentrator reflectance based on the refractive index of glass obtained from reflectance and transmittance measurements. This approach improved accuracy of solar-averaged reflectance from 2.9% to 0.4% compared to the use of existing reference data. Reflectance variations with incidence angles are negligible up to $60^{\circ}C$ at various glass thicknesses. When concentrators are contaminated with dust during 2 months specular reflectance loss of vertically exposed concentrators is less than 7%. However for horizontally exposed concentrators the loss significantly increases up to 40% while dependence of reflectance on incidence angles becomes strong. Measurements of hemispherical reflectance indicate that 80 percentage of the loss comes from scattering rather than absorption by dust. Data of refractive index and reflectance provided in the current study will help estimate or model the concentrated solar flux.

• 수산해양교육연구
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• 제25권5호
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• pp.1079-1087
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• 2013

Florfenicol(FF)을 넙치(평균체중 $700{\pm}50$ g, $23{\pm}1.5^{\circ}C$)에 1일 1회 경구(20 mg/kg BW) 투여한 다음, 경시적(1시간~168시간)으로 혈청 내 FF의 잔류량을 HPLC로써 분석하였다. FF의 경구 투여에 따른 넙치 체내 약물 혈중농도 측정결과를 바탕으로 two-compartment model로 WinNonlin program을 이용하여 FF의 흡수, 배설, 반감기 등 약물동태학적 매개변수(parameter)를 조사하였다. 혈청중 농도-시간곡선하 면적(AUC)은 22.51 ${\mu}g{\cdot}h/mL$, 혈중최고농도($C_{max}$)는 0.84 ${\mu}L/mL$, 혈중최고농도에 도달하는 시간($T_{max}$)은 8.62 시간, 약물이 혈중에서 완전히 0이 되는 시점인 예상소실시간(Et)은 447 계산되었다. 본 연구에서 얻어진 결과는 넙치에 FF를 처방하여 치료 계획을 수립할 때 유용하게 활용될 것으로 여겨진다.

• 설비공학논문집
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• 제26권1호
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• pp.1-7
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• 2014

A field test of a 70 kW heat pump system with flue gas heat recovery was performed by an experiment at the Korea Institute of Energy Research. The flue gas is exhausted from a 320 RT absorption chiller-heater in the heating season. Using this flue gas, source water of the heat pump is heated by a condensed-type heat exchanger in the chimney. The operating characteristics of the heat recovery heat pump system were analyzed. Based on the results of the experiments, operating maps were obtained, and an optimum operating range is suggested, in which the return and heat source water temperature are $51^{\circ}C$ and $31^{\circ}C$, respectively. Additionally, economic analysis of this system was conducted and about 50% energy cost savings can be expected in the heating season.

• 공업화학
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• 제5권1호
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• pp.81-89
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• 1994

고성능 니켈/금속수소 축전지를 개발하기 위하여 전극용량도 비교적 높고, 합금가격이 저렴한 Mm계 전극에 대하여 P-C-T 특성, 충방전 특성, microencapsulation 방법 및 그 효과 등에 관한 연구를 수행하였다. P-C-T 특성조사로부터 플라토압력, 수소저장량을 구하였는데, Mm계 합금인 경우는 각각 0.4기압, 310mAh/g으로 나타났다. Microencapsulation 처리를 함으로써 도전재를 혼합한 전극보다 전극용량 및 전극의 안정성을 향상시켰으며, 또한 전처리없이 microencapsulation처리가 가능하였다. Microencapsulation 처리한 Mm계 합금의 전극용량은 240~250 mAh/(0.2 C)이었다.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.1
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• pp.111-116
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• 2006

The microstickes control effects of some fixing agents, including an inorganic PAC, an organic polyamine (PA) and polydiallydimethyl ammonium chloride (Pdadmac), and a high cationic starch (HCS), were investigated, together with their effects on wet end performances and physical properties of handsheets. Despite that the HCS and Pdadmac had lower cationic charge densities than the PA and PAC (the HCS being even lower), they gave higher zeta potentials to fibers, and lower turbidities, cationic demands and residual COD contents to the pulp liquid phases than the PA and PAC did. In all cases, the HCS showed even better effects than the Pdadmac. In addition, drainage speed was also much higher by the HCS treatments although paper formation was worsened. All the phenomena showed that the HCS can fix more dissolved and colloidal substances to cellulose fibers, indicating that the HCS functioned mainly with flocculation and even hydrogen bonding mechanisms. Data on optical properties further indicated that the HCS interacted preferentially with colloidal substances, since it fixed more 'dirty' microstickes to fibers which decreased more sheet brightness while increasing more sheet opacity (with both higher light absorption and scattering coefficients). Interestingly, the organic fixing agents did not decrease tensile, tearing, and folding strengths of paper sheets made from 100% recycled newsprint pulp, except when they were dosed in high amounts. On the contrary, the inorganic PAC had more serious negative effects on the strength properties, especially on folding endurance. The study suggested that proper use of the HCS can lead to better microstickies control effects than traditional agents and methods.

• 한국세라믹학회지
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• 제44권4호
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• pp.194-197
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• 2007

Polyacrylonitrile (PAN)/$Fe_2O_3$ nanocomposite membranes with a thickness of 0.02 mm were electrospun by adding 0 to 5 wt% of $Fe_2O_3$ into PAN. The surface tension, density, kinematic viscosity and dynamic viscosity of the PAN solution were determined to be $33.8{\pm}1mN/m$, 0.9794 g/ml, $1548.6mm^2/sec$ and 1516.7 cP, respectively. The average diameters of PAN fibers containing 0, 1 2, 3, and 4 wt% $Fe_2O_3$ particles were 300, 260, 210, 130, and 90 nm, respectively. Fourier-transform infrared spectroscopy results showed that the addition of $Fe_2O_3$ nanoparticles to the PAN mat reduced the absorption peak intensity at $2242cm^{-1}$ ($C{\equiv}N$ bond) while it caused a sharp increase in the peak intensity at $2356cm^{-1}$(C=O bond). Thus, it appears that an appropriate amount of $Fe_2O_3$ nanoparticles in the PAN backbone leads to an improvement of the performance of the $CO_2$ gas sensor, most likely due to the change of functional groups in the membrane.

• 한국세라믹학회지
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• 제51권3호
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• pp.162-169
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• 2014

This paper introduces a microwave-assisted synthesis method to prepare hybrid $Bi_2Se_3-GR/TiO_2$ nanocomposites, which exhibit superior properties over single component materials. The as-prepared composites were characterized by XRD, UV-vis absorbance spectra, SEM,TEM, EDX, and BET analyses, revealing uniform covering of the graphene nanosheet with $Bi_2Se_3$ and $TiO_2$ nanocrystals. For visible light photocatalysis of Rh.B, a significant enhancement in the reaction rate was consequently observed with $Bi_2Se_3-GR/TiO_2$ composites. The degradation rate($k_{app}$) obtained for sonophotocatalysis was $6.8{\times}10^{-3}min^{-1}$, roughly 2.2 times better than that of VL photocatalysis under higher concentrations of Rh.B. The sonophotocatalysis was faster due to greater formation of reactive radicals as well as an increase of the active surface area of the $Bi_2Se_3-GR/TiO_2$ composites. The high activity is attributed to the synergetic effects of high charge mobility and red shift of the absorption edge of $Bi_2Se_3-GR/TiO_2$.

• 대한기계학회논문집A
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• 제40권8호
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• pp.737-742
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• 2016

다공성 탄성체는 기름유출과 같은 상황에서 적용 가능한 선택적 흡수재로 각광을 받고 있다. 다공성 탄성체의 선택적 흡수효율은 표면 거칠기, 물리화학적 처리기법, 수압안정성 등의 영향을 받는다. 본 연구에서는 PDMS(polydimethylsiloxane), 미소 소금입자 및 계면활성제(silwet L-77)를 이용하여 다공성 PDMS를 제작하는 방법에 대해 설명한 후, 제작과정 중 물리화학적 처리를 통해 상기 다공성 PDMS의 소수성을 강화하거나 혹은 그 특성을 친수성으로 만드는 방법에 대해 기술한다. 물리적 처리방법으로는 소금입자의 크기조절을 통해 공극 크기(혹은 표면 거칠기)를 조절하고 화학적 처리방법으로는 계면활성제의 혼합비를 조절하여 표면 에너지를 변화시킨다. 제작된 다공성 PDMS를 이용하여 접촉각 및 흡수율을 측정함으로써 소금입자의 직경과 계면활성제의 혼합비가 다공성 PDMS의 접촉각과 흡수율에 미치는 영향을 정량적으로 측정한다.

• Asian-Australasian Journal of Animal Sciences
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• 제27권3호
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• pp.310-315
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• 2014

Cellular retinol-binding protein II (CRBP II) belongs to the family of cellular retinol-binding proteins and plays a major role in absorption, transport, and metabolism of vitamin A. In addition, because vitamin A is correlated with reproductive performance, we measured CRBP II mRNA abundance in erlang mountainous chickens by real-time PCR using the relative quantification method. The expression of CRBP II showed a tissue-specific pattern and egg production rate-dependent changes. The expression was very high (p<0.05) in jejunum and liver, intermediate in kidney, ovary, and oviduct, and lowest (p<0.05) in heart, hypothalamus, and pituitary. In the hypothalamus, oviduct, ovary, and pituitary, CRBP II mRNA abundance were correlated to egg production rate, which increased from 12 wk to 32 wk, peaked at 32 wk relative to the other time points, and then decreased from 32 wk to 45 wk. In contrast, the expression of CRBP II mRNA in heart, jejunum, kidney, and liver was not different at any of the ages evaluated in this study. These data may help to understand the genetic basis of vitamin A metabolism, and suggest that CRBP II may be a candidate gene to affect egg production traits in chickens.

• 전기학회논문지
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• 제63권11호
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• pp.1615-1621
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• 2014

A wireless tram which runs without catenary and instead uses batteries installed in the tram has been recently researched actively. This paper presents a new method maximizing absorption of regenerative energy of a wireless tram and extending life cycle of the energy storage device in the wireless tram by applying line-optimized charging and discharging scenario. Energy efficiency and life cycle of energy storage system (ESS) are highly dependent on the characteristic of operating conditions. For example, frequent charge and discharge with high power cause the problems that decrease the battery life cycles. Hybrid energy storage system (HESS) is combination of two ESSs which have complementary characteristics to each other. HESS can provide even better functionality and performance than the battery only ESS due to the synergy effect of two ESSs. This paper also provides a power distribution strategy and driving scenarios which increase the life cycle and energy efficiency of the HESS consisting of a battery and an ultra-capacitor. The developed strategy was tested and verified by a hardware-in-the-loop-simulation (HILS) system which emulates the a wireless tram.