• Environmental Engineering Research
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• 제24권1호
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• pp.54-62
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• 2019

The effects of UV wavelength and dissolved organic carbon (DOC) on the formation of dissolved gaseous mercury (DGM) were investigated in a controlled environment. To remove any other influences than UV wavelength and DOC, purified water was used as the working solution. DGM was instantly produced with irradiation of all UV lights even without DOC; whereas, there was no noticeable increase of DGM during irradiation of visible light. The amount of formed DGM increased as the DOC concentration increased even in dark conditions; however, UV-B irradiation significantly promoted DGM production with DOC present. The rate constants of reduction ranged from $1.4{\times}10^{-6}s^{-1}$ to $3.5{\times}10^{-5}s^{-1}$, with the lower values occurring under the dark condition without DOC and the higher values resulting under UV-B irradiation and high DOC concentration. However, DGM production was not linearly correlated with the DOC concentration at higher range of DOC in this study. Future studies should investigate the effects of DOC concentration on mercury (Hg) reduction over the broad range of DOC concentrations with different DOC structures and with other influencing parameters.

• 대한금속재료학회지
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• 제49권2호
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• pp.167-173
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• 2011

Nickel cobalt ferrite($Ni_{0.5}Co_{0.5}Fe_2O_4$) powder was prepared through the ceramic route by the calcination of a stoichiometric mixture of NiO, CoO and $Fe_2O_3$ at $1100^{\circ}C$. The pressed pellets of $Ni_{0.5}Co_{0.5}Fe_2O_4$ were isothermally reduced in pure hydrogen at $800{\sim}1100^{\circ}C$. Based on the thermogravimetric analysis, the reduction behavior and the kinetic reaction mechanisms of the synthesized ferrite were studied. The initial ferrite powder and the various reduction products were characterized by X-ray diffraction, scanning electron microscopy, reflected light microscope and vibrating sample magnetometer to reveal the effect of hydrogen reduction on the composition, microstructure and magnetic properties of the produced Fe-Ni-Co alloy. The arrhenius equation with the approved mathematical formulations for the gas solid reaction was applied to calculate the activation energy($E_a$) and detect the controlling reaction mechanisms. In the initial stage of hydrogen reduction, the reduction rate was controlled by the gas diffusion and the interfacial chemical reaction. However, in later stages, the rate was controlled by the interfacial chemical reaction. The nature of the hydrogen reduction and the magnetic property changes for nickel cobalt ferrite were compared with the previous result for nickel ferrite. The microstructural development of the synthesized Fe-Ni-Co alloy with an increase in the reduction temperature improved its soft magnetic properties by increasing the saturation magnetization($M_s$) and by decreasing the coercivity($H_c$). The Fe-Ni-Co alloy showed higher saturation magnetization compared to Fe-Ni alloy.

• 한국염색가공학회지
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• 제25권4호
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• pp.314-326
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• 2013

The purpose of this research is to analyze the effects of Dansam and Sappan wood extract to perform combination dyeing on silk fabrics, with respect to color changes, fastness (washing, dry cleaning, perspiration, rubbing and light fastness), and functionality (antibacterial activity and deodorization). Combination dyeing was performed by first combining Dansam with Sappan wood, then Sappan wood with Dansam, in these orders. Given the changes in the combination ratio, pre-mordant treatment was performed. Looking at the surface colors of each dye, Dansam generally produces YR color series, while Sappan wood produces YR, R, and RP color series. The effects of changing the order in which combination dying was performed on the surface colors were as follows. First, combination dyeing (A) was performed by using Dansam before Sappan wood, to produce YR and R color series. Then combination dyeing (B) was performed by using Sappan wood before Dansam, to produce YR, R, and RP color series. By visual inspections, more similar color changes of the combination dyeing were noticed with the post-dyeing material rather than the pre-dyeing material. Therefore, it was presumably confirmed that surface color changes of combination dyeing were greatly influenced by the post-dyeing color. Individual dyeing tests for fastness showed that Dansam was comparatively superior to Sappan wood, which demonstrated lower fastness to washing, dry cleaning, perspiration, and light, relatively. The fastness of combination dyed samples was shown middle, but similar fastness to the post-dye material, The fastness of (B) method was higher than (A) method in the washing and light fastness. This confirms that color fastness from combination dyeing was considerably influenced by the post-dye material. It was found that all dyed samples had a very high bacterial reduction rate of 99.9% and high deodorization rate of 95%.

• Nano
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• 제13권11호
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• pp.1850127.1-1850127.13
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• 2018

Bi metal deposited on $Bi_2MoO_6$ composite photocatalysts have been successfully synthesized via a simple reduction method at room temperature with using $NaBH_4$ as the reducing agent. The photocatalytic activity of the composite was evaluated by degradation of rhodamine B (RhB) and bisphenol A (BPA) solution under visible light. The rate constant of $Bi/Bi_2MoO_6$ composite to RhB is 10.8 times that of $Bi_2MoO_6$, and the degradation rate constant of BPA is 6.9 times of that of $Bi_2MoO_6$. Nitrogen absorption-desorption isotherm proved that the increase of specific surface area is one of the reasons for the improvement of photocatalytic degradation activity of $Bi/Bi_2MoO_6$ composites. The higher charge transfer efficiency of $Bi/Bi_2MoO_6$ is found through the characterization of the photocurrent and impedance, which are attributed to the surface plasmon resonance (SPR) effect produced by the introduction of the metal Bi monomer in the composite. Free radical capture experiments proved that cavitation is the main active species. Based on the above conclusions, a possible mechanism of photocatalytic degradation is proposed.

• ALGAE
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• 제38권2호
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• pp.141-150
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• 2023

Light quality is a common environmental factor which influences the metabolism of biochemical substances in algae and leads to the response of algal growth and development. Pyropia yezoensis is a kind of economic macroalgae that naturally grows in the intertidal zone where the light environment changes dramatically. In the present study, P. yezoensis thalli were treated under white light (control) and monochromatic lights with primary colors (blue, green, and red) for 14 days to explore their physiological response to light quality. During the first 3 days of treatment, P. yezoensis grew faster under blue light than other light qualities. In the next 11 days, it showed better adaptation to green light, with higher growth rate and photosynthetic capacity (reflected by a higher rETR_max = 61.58 and E_k = 237.78). A higher non-photochemical quenching was observed in the treatment of red light than others for 14 days. Furthermore, the response of P. yezoensis to light quality also results in the difference of photosynthetic pigment contents. The monochromatic light could reduce the synthesis of all pigments, but the reduction degree was different, which may relate to the spectral absorption characteristics of pigments. It was speculated that P. yezoensis adapted to a specific or changing light environments by regulating the synthesis of pigments to achieve the best use of light energy in photosynthesis and premium growth and metabolism.

• 전자공학회논문지
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• 제51권1호
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• pp.137-144
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• 2014

본 논문에서는 OLED 디스플레이에서 히스토그램 정합 기법을 통해 인지 화질을 고려한 파워 소모 저감 기법을 제안한다. 기존 방법의 경우 영상의 클리핑 에러를 정확하게 분석할 수 없어 클리핑 에러를 갖는 픽셀들이 집중된 경우 화질 저하가 크게 발생한다. 제안한 방법은 이를 해결하기 위해서 다른 특성을 갖는 여러 영상들에 대한 히스토그램들을 생성하고 각 영상에 대해 인지 화질을 고려한 최적의 클리핑 비율을 계산 및 데이터베이스에 저장한다. 이를 입력 영상에 대한 히스토그램과 정합도를 비교하여 최적의 클리핑 비율을 선택하여 출력 영상의 화질 저하를 막는다. 실험 결과 제안한 방법은 기존 방법 대비 평균 PSNR과 SSIM을 각각 최대 15.795 dB, 0.036 향상시킬 수 있었다.

• 한국작물학회지
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• 제36권2호
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• pp.127-133
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• 1991

출수기 전후 일조조건이 수량 및 수량구성요소에 미치는 영향을 구명하고자 벼의 생식생장기인 감수분열기부터 출수후 20일까지 3개 품종군별로 자연광 차광 50%와 75%의 3수준으로 차광처리를하여 시험을 실시한 결과를 요약하면 다음과 같다. 1 온도 및 광도는 차광정도가 클수록 낮아졌고 일중변화는 오후 1시>오후 4시>오전 10시 순 이었다. 2. 출수기는 대체로 2～3일 정도 지연되었으나 상풍벼와 봉광벼는 차광을 하여도 자연광과 차이가 없고 성숙일수는 대체로 전 공시품종에서 8～12일 정도 지연되었다 3. 간장 및 추출도는 품종간에 관계없이 차광 정도가 클수록 간장은 길어지고 추출도는 짧아졌으며 특히 차광 75%에서는 그 정도가 심하였다. 4. 지경퇴화는 일차지경보다 이차지경에서 차광정도가 클수록 퇴화율이 켰다 5. 영화퇴화도 지경퇴화와 비슷한 경향이었으나 조생종군에서 심한 퇴화율을 보였다 6. 영화수는 차광을 했을때 수당 12～15입이 줄었으며 현미 천입중도 차광처리했을때, 감소하는 경향이었으나 그 중에서 소백벼 여명벼 등은 그 폭이 컸다. 7. 차광정도에 따라 불임율은 높았고 등숙율은 감소 경향이 있다. 8. 수량은 차광 50%에서 30～40% 감소하였으며 75% 차광에서는 50%정도 감소하였다.

• 한국환경생태학회지
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• 제35권5호
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• pp.569-575
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• 2021

도심 교통섬과 도시숲 내부에서 미세먼지 농도와 영향 인자를 조사하여 숲의 미세먼지 효과를 분석하였다. 서울시 동대문구 홍릉시험림(도시숲)과 동대문구 청량리역 교차로에 조성된 숲(교통섬)에서 미세먼지 농도를 2018년 1월부터 11월까지 광산란법 기기를 적용하여 측정하였다. 연구 기간 동안 도시숲과 교통섬의 PM₁₀ 평균농도는 12.5 ㎍/m³, 15.7 ㎍/m³으로 나타났으며, PM_2.5의 평균농도는 6.6 ㎍/m³, 6.9 ㎍/m³으로 나타났다. 환경부 도시대기 측정망과 도시숲의 농도를 비교해본 결과, PM₁₀의 저감율은 도시숲에서 66.9±28.6%, 교통섬에서 58.6±44.1%로 나타났고, PM_2.5의 경우 71.3±23.0%, 64.9±31.3%로 각각 나타났다. 미세먼지 저감율의 차이는 도시숲의 규모와 구조의 차이와 관련이 있을 것이며, 풍속은 저감 요인으로 판단된다.

• 인터넷정보학회논문지
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• 제24권2호
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• pp.57-66
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• 2023

현재, 에너지 효율 향상으로 소비감축을 시행하는 새로운 에너지 시스템이 대두되고 있다. 이에 스마트그리드가 확산되면서 계시별 요금제가 확대되고 있다. 계시별 요금제는 계절별 / 시간별로 요금을 다르게 적용해 사용량에 따라 요금을 내는 요금제이다. 본 연구에서는 에너지 전력 사용량 데이터를 예측하기 위해, 온도/요일/시간/계절 등 외부 요인을 고려하고 시계열 예측 모델인 LSTM을 활용한다. 이러한 에너지 사용량 예측 모델을 기반으로 기기별 사용패턴을 분석하여 전력 에너지를 최대부하시간대에서 경부하시간대로 수요이전 함으로써 에너지 사용요금을 절감한다. 기기별 사용패턴을 분석하기 위해서는 시간대별로 기기의 사용량 패턴을 학습 및 분류하는 clustering 기법을 사용한다. 정리하자면, 본 연구에서는 사용자의 전력 데이터 사용량을 기반으로 사용량과 사용 요금을 예측 및 기기별 사용패턴을 분석하고 분석 기반의 맞춤형 수요이전 서비스를 제공함으로써 사용자에게 요금 절감 효과를 가져다 준다.

• 한국염색가공학회지
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• 제27권1호
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• pp.80-95
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• 2015

In this study, the properties such as color, dye uptake and antibacterial function were examined through the application of combination dyeing and mixed dyeing with extracts from Humulus japonicus(hwansam) and the pruned branches of Prunus persica(peach) tree. In terms of dye uptake and surface color changes subject to the kind of mordants, methods and mixing ratio of dye, it was found that fabrics dyed by the pre-mordanting method with $CuSO_4$ showed the red green yellow group colors, which were not seen in fabrics dyed with hwansam only. Color fastness was found strong at grade 4-5 with 96.3% of UV protection ratio. While the fastness to light was as fair as grade 3, it showed an excellent result of 99.9% bacteria reduction rate against Staphylococcus aureus with fair 58% deodorization rate and 21.2% antibacterial rate against Klebsiella pneumoniae. As stated above, the combination and mixed dyeing resulted in the meaningful outcomes with regard to color variations, dye uptake, color fastness and functional properties.