• Applied Chemistry for Engineering
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• v.27 no.1
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• pp.1-9
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• 2016

The co-culture system of microalgae and bacteria enables simultaneous removal of BOD and nutrients in a single reactor if the pair of microorganisms is symbiotic. In this case, nutrients are converted to biomass constituents of microalgae. This review highlights the importance and recent researches using symbiotic co-culture system of microalgae and bacteria in wastewater treatment, focusing on the removal of nitrogen and phosphorus. During wastewater treatment, the microalgae produces molecular oxygen through photosynthesis, which can be used as an electron acceptor by aerobic bacteria to degrade organic pollutants. The released $CO_2$ during the bacterial mineralization can then be consumed by microalgae as a carbon source in photosynthesis. Microalgae and bacteria in the co-culture system could cooperate or compete each other for resources. In the context of wastewater treatment, positive relationships are prerequisite to accomplish the sustainable removal of nutrients. Therefore, the selection of compatible species is very important if the co-culture has to be utilized in wastewater treatment.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.94-94
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• 2012

섬유산업은 원가 경쟁력 향상과 산업 고도화에 필요한 미래형 저에너지 염색가공 핵심 기술을 통한 고부가가치 섬유제품의 창출과 섬유산업의 선진화달성에 꾸준히 노력을 해 왔다. 염색가공업의 에너지 소비는 섬유산업에서 염색가공업이 연료 사용량의 77%, 전기사용량의 54%를 차지하여 섬유산업의 에너지절감을 위해서는 염색가공 공정에서의 에너지 절감이 가장 중요하다. 국내 염색가공 분야의 4백여 업체를 대상으로 실시한 애로 기술에 관한 설문 조사결과에 따르면 염색공업의 에너지 절약형 구조로의 전환을 위해서 가장 시급히 요구되는 우선기술 1순위는 에너지절약형 염색가공 공정기술로 에너지 절감의 필요성을 반영하고 있다. 효소(Enzyme)가 섬유산업에 도입되기 시작한 것은 면섬유의 호발에 아밀라제가 사용되기 시작하면서 부터이며, 최근 유럽선진국들의 강화된 환경규제와 눈부신 바이오테크놀러지(Biotechnology)의 발전에 기인하여 섬유산업에서 관심과 적용이 확대되고 있다. 섬유산업에서 효소적용의 장점은 효소 그 자체가 자연산물이기 때문에 생분해 되고 중성에 가까운 pH에서 반응하므로 처리액이 환경문제를 일으키지 않으며, 기질특이성을 가져 매우 선택적으로 반응하여 부반응으로 인한 섬유의 손상을 최소화 하는 효과를 들 수 있으며, 무엇보다 소량 저온반응으로 인한 에너지절감이 가장 큰 장점이라 할 수 있다. 실제 섬유산업에서는 전분호제를 제거하는 아밀라아제, 데님워싱 및 면섬유의 후가공에 사용하는 셀룰라아제, 표백 후 잔류하는 과산화수소를 제거하는 카탈라제 등을 적용하는 사례가 많아지고 있으며, 이 밖의 다양한 공정에 효소 이용연구가 활발히 진행되고 있다. 본 연구에서는 그 동안 섬유 업체에서 직물의 표면 잔털을 제거하여 매끄러운 외관과 선명한 색상을 재현하기위해 후가공으로 셀룰라아제를 이용했던 공정을 개선하여, 효소를 이용한 정련-Bio polishing-염색의 3공정을 1욕처리를 통해 기존 단독으로 진행되어진 기존제품과의 중량, 외관, 색상재현성, 정련성 등을 비교하여 에너지 절약형 공정기술의 효과를 극대화 해보았다.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.4
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• pp.56-62
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• 1999

In this study, (Ba, Sr)$TiO_3$ thin films were etched with $Cl_2$/Ar gas mixing ratio in an inductively coupled plasma (ICP) by varying the etching parameter such as rf power, dc bias voltage, and chamber pressure. The etch rate was 56 nm/min under $Cl_2$/($Cl_2$+Ar) gas mixing ratio of 0.2, rf power of 600 W, dc bias voltage of 250 V, and chamber pressure of 5 mTorr. At this time, the selectivity of BST to Pt, $SiO_2$ was respectively 0.52, 0.43. The surface reaction of the etched (Ba, Sr)$TiO_3$ thin films was investigated with X-ray photoelectron spectroscopy (XPS). Ba is removed by chemical reaction between Sr and Cl to remove Sr. Ti is removed by chemical reaction such as $TiCl_4$ with ease. The results of secondary ion mass spectrometer (SIMS) analysis compared with the results of XPS analysis and the results were the same.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.7
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• pp.773-778
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• 2011

Accelerometers are widely used to measure the lateral vibrations of pipe-like structures such as a gun tube under impulse loads. Stress waves that precede the lateral vibrations due to the explosion within a gun contribute little to the vibrations, but saturate the accelerometer input. A mechanical filter eliminates this high-frequency stress wave and only transmits the signal corresponding to the lateral vibrations. The mechanical filter consists of a mechanical structure for mounting the accelerometers and a damping material. The low-pass filter characteristics are determined from the equivalent damping and stiffness property of this damping material. In this paper, we tested nine commercially available damping materials for their vibration characteristics by using a test rig. We also observed the change in the vibration characteristics while compressing the material. We designed and manufactured a mechanical filter and verified its filtering performance.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.11
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• pp.87-92
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• 2005

This paper analyzes the performance for an improved multistage parallel interference cancellation (PIC) technique with a reverse-link synchronous transmission technique (RLSTT) for DS-CDMA system in a frequency-selective Rayleigh fading channel with an imperfect power control scheme. The performance degradation due to power control error (PCE), which is approximated by a log-normally distributed random variable, is estimated as a function of the standard deviation of the PCE. The uncoded bit error performance is evaluated in order to estimate the system capacity. Comparing with the conventional one-stage PIC system, we show achievable gain around $60\%$ by the RLSTT even in the presence of PCE. We conclude that the capacity can be further improved via RLSTT, which alleviates the detrimental effects of the PCE

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.364-367
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• 2013

In this paper, we propose a method about reducing facial blemishes using Morphological Operation. First, we detect skin region using pixel data of RGB's each channel image. we create histogram of skin region R, G, B channel and save 3 pixel values that are high frequency pixel value in each channel. After than, we find facial blemishes using Black-hat operation. The pixel value of facial blemishes changes average of its pixel value, 8-neighborhood pixel value and high frequency pixel values. And the facial blemishes pixel is blurred with median filter. The result of this test with facial pictures that have facial blemishes, we prove that this system that correct the face skin using reduction facial Blemishes is more efficient method than correct the face skin just using lighting up.

• Journal of Korean Society on Water Environment
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• v.20 no.6
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• pp.625-630
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• 2004

Granular media filtration is used almost universally as the last particle removal process in conventional water treatment plants. Therefore, superb particle removal efficiency is needed during this process to ensure a high quality of drinking water. However, every particle can not be removed during granular media filtration. Besides the pattern of particle attachment is different depending on physicochemical aspects of particles and suspension. Filtration experiments were performed in a laboratory-scale filter using spherical glass beads with a diameter of 0.55 mm as collectors. A single type of particle suspension (Min-U-Sil 5) and alum coagulation was used to destabilize particles. The operating conditions were similar to those of standard media filtration practice: a filtration velocity of 5 m/h. More favorable particles, i.e., particles with smaller surface charge, were well attached to the collectors especially during the early stage of filtration when zeta potential of particles and collectors are both negative. This selective attachment of the lower charged particles caused the zeta potential distribution (ZPD) of the effluent to move to a more negative range. On the other hand, the ZPDs of the effluent moved from more positive to less positive when the surface charge of particles was positive and this result was thought to be caused by ion transfer between particles and collectors.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.7C
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• pp.716-725
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• 2005

In this paper, we propose a new approach for the reduction of the dynamic false contours, which detects and compensates false contour artifacts adaptively. First, we develop a simple but effective method to select the pixels that are likely to cause the motion artifacts, based on the distribution of pixel values. Then, we merge the selected pixels into several regions using tree structure. Next, we reduce number of gray levels within the regions slightly to reduce the false contours. Note that reducing number of gray levels yield the distortion, thus it is applied only to the selected regions, instead of the whole picture. Intensive simulations on real moving image show that the proposed algorithm alleviates the dynamic false contours effectively with tolerable computational complexity.

• Korean Chemical Engineering Research
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• v.56 no.5
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• pp.687-693
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• 2018

The selective removal and recovery of fermentation inhibitors during purification of sugars from biomass hydrolysates can increase the economic efficiency of the entire process to produce bioalcohol from lignocellulosic biomass. This study investigated the effect of furans in phenols-free biomass hydrolysate on acetic acid extraction in an emulsion liquid membrane system. Under specific operating conditions, more than 99% of acetic acid could be extracted within 5 minutes, and the degrees of extraction of furfural and 5-hydroxymethylfurfural were about 10% and 4%, respectively. The extraction rate of acetic acid was also lower at a higher initial concentration of furfural in the feed phase, which was greater for furfural than 5-hydroxymethylfurfural. Thus, if furfural is first removed from the hydrolysate prior to acetic acid extraction, emulsion liquid membrane would be a more economically efficient way of removing acetic acid.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.3
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• pp.608-618
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• 2007

Image binarization is an important preprocessing to identify the object of interest by dividing pixels into the background and object. We proposes efficient binarization method and a stroke reconstruction method of the low quality character image for an effective character recognition. First, the character image is binarized by using the both advantages of local and global thresholding method and then the noise elimination around the character stroke and the hole filling on the stoke by the analysis of the binarized stroke image are performed to enhance the quality of the character stroke. Proposed binarization algorithm for character image achieved an efficiency of both processing speed and performance by the adaptive threshold selection. Moreover, We could get a high qualify binary image by a stroke reconstruction of the step-by-step denoising process.