• 한국식품영양과학회지
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• 제34권2호
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• pp.277-284
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• 2005

좁쌀 약주의 가열살균에 따른 품질열화의 대안으로 비 가열공정 시스템인 미세 및 한외여과용 중공사막(hallow fiber membrane) 카트리지 (cartridge)의 도입을 통한 좁쌀 약주의 고품질화를 시도하였다. 비 가열살균 좁쌀 약주의 제조 및 저장 중 품질변화를 조사하기 위하여 0.65, 0.45, 0.2및 0.1 $\mu$m의 MF(micro-filtration) 카트리 지와 500 K의 UF(ultrafiltration) 카트리지 등 중공사막의 공극의 크기에 따른 제조공정상의 효용성을 시험하였다. 시험한 모든 막 카트리지에서 미생물 제거 능력은 확인되었으나 여과 속도 및 안전성 면에서 0.45 $\mu$m 막 카트리지가 적당한 것으로 조사되었다. 저장 중 모든 시료에서 환원당 및 색택 변화의 차이가 측정되었는데, 6개월 저장 결과 가열살균 약주가 비 가열 약주에 비하여 투명도(L 값)가 감소하고 황청도(b 값)는 크게 증가하여 색택이 어두워지는 현상이 관찰되었다. 저장 중 환원당의 감소는 색택이 진해지는 비효소적 갈변과 관련이 있는 것으로 추정되며, 다른 화학적 성분에 대한 변화는 가열 살균과 비 가열 간에 차이가 거의 없는 것으로 조사되었다. 관능검사 결과 카트리지의 종류에 따른 좁쌀약주의 품질에 대한 차이는 인정되지 않았으나, 가열살균과 비 가열에 대한 품질은 유의적인 차이가 있었으며 비 가열처리 공정이 더 우수한 것으로 평가되었다.

• 분석과학
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• 제13권2호
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• pp.241-249
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• 2000

본 연구는 수질계의 용존 유기 탄소화합물의 주성분인 부식산을 화학적 산화방법 중 오존처리를 사용하여 $UV_{254}$ 흡광도, TOC, $^{13}C-NMR$, 한외여과법 등을 이용하여 오존 처리후의 특성 변화를 조사하였으며, 오존 산화물의 GC/MS 분석을 통하여 포름알데히드, 아세트알테히드, 아세톤, 글리옥살 및 메틸글리옥살 등의 생성을 확인하였다. $UV_{254}$ 흡광도와 TOC의 측정결과 부식산 농도 20, 100ppm 모두 오존처리시간 20분 이내에서 80%의 색도 감소율과 30분 이내에서 40-50%의 TOC 제거율을 나타냈고, 그 이후의 처리시간에서는 일정한 색도 감소율 및 제거율을 나타냈다. $^{13}C-NMR$, 한외여과법을 통한 실험결과, 오존처리에 의해 고분자량의 부식산이 산화, 분해됨으로서 알데히드, 카르복실산 등이 풍부한 저분자량의 단위체로 나뉘어지며 생물학적 분해가 용이한 지방족 탄소가 풍부한 구조로 전환됨를 확인하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.353-353
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• 2008

Carbon nanotubes (CNTs) are attractive for field emitter because of their outstanding electrical, mechanical, and chemical properties. Several applications using CNTs as field emitters have been demonstrated such as field emission display (FED), backlight unit (BLU), and X-ray source. In this study, we fabricated a CNT cathode using transparent ultra-thin CNT film. First, CNT aqueous solution was prepared by ultrasonically dispersing purified single-walled carbon nanotubes (SWCNTs) in deionized water with sodium dodecyl sulfate (SDS). To obtain the CNT film, the CNT solution in a milliliter or even several tens of micro-litters was deposited onto a porous alumina membrane through vacuum filtration process. Thereafter, the alumina membrane was solvated by the 3 M NaOH solution and the floating CNT film was easily transferred to an indium-tin-oxide (ITO) glass substrate of $0.5\times0.5cm^2$ with a film mask. The transmittance of as-prepared ultra-thin CNT films measured by UV-Vis spectrophotometer was 68~97%, depending on the amount of CNTs dispersed in an aqueous solution. Roller activation, which is a essential process to improve the field emission characteristics of CNT films, increased the UV-Vis transmittance up to 93~98%. This study presents SEM morphology of CNT emitters and their field emission properties according to the concentration of CNTs in an aqueous solutions. Since the ultra-thin CNT emitters prepared from the solutions show a high peak current density of field emission comparable to that of the paste-base CNT emitters and do not contain outgassing sources such as organic binders, they are considered to be very promising for small-size-but-high-end applications including X-ray sources and microwave power amplifiers.

• 상하수도학회지
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• 제19권5호
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• pp.537-546
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• 2005

This study was carried out to evaluate EPS and SMP variation of sludge and effluent in nitrification and denitrification process with zeolite addition, a possible reduction of effluent DOC by URC(Ultra Rapid Coagulation) process. As a biological wastewater treatment result, EPS formation of both aeration and anoxic sludges are not affect by SRT variation. However, EPS concentration of sludges is higher in aeration tank than in anoxic tank by 6~8 mg EPS/ g VSS. Linear relationship between SMP to DOC indicates that SMP of bulk solution contributes to most of the biological treatment effluent DOC. DOC and turbidity removal efficiency was more improved with URC process than in a conventional coagulation. For pretreatment of UF filtration DOC removal was advanced by URC process than only UF filtration.

• 한국잠사곤충학회지
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• 제43권1호
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• pp.41-48
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• 2001

The purification, dissolution and powdering of stained waste silk obtained from weaving and dyeing process were studied for the surface modification of textile fabric and plastic materials. The whiteness of stained waste silk could be improved through degumming and bleaching with sodium hydrosulfite. The water-soluble fibroin solution can be obtained by dissoving the degummed waste silk in a boiling solution of 50% calcium chloride for 60 minutes. The salts and heavy metals contained in fibroin solution were removed by electric dialysis, wool fiber filtration and gel filtration chromatography. The fibroin powder was prepared by using a fine grinder after the alkali treatment for weakening the silk fiber. The fine fibroin powder of particle size around 30 ㎛ was obtained with a ultra fine-mill, while it was finer below 10 ㎛ with a ball-mill. The dissolved or powdered silk was applied to the surface of fabric with addition of the binder (a urethane resin). The moisture content of polyester and nylon fabrics treated with the silk solution was improved due to hygroscopic property of silk. The fine fibroin powder mixed with the binder ws coated on the surface of synthetic film by use of the air pressed sprayer. It was revealed that the hygroscopicity as well as the softness of fibroin powder coated film was much improved. Therefore, it is thought that the fine silk fibroin powder is applicable as an coating agent for the surface modification of plastic and synthetic leather.

• Membrane and Water Treatment
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• 제7권4호
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• pp.355-365
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• 2016

The improvement of fouling resistance of porous polymeric membrane is one of the most important targets in membrane preparation for water purification in many process like wastewater treatment. Membranes can be modified by various techniques, including the treatment of polymer material, blending of hydrophilic polymer into polymer solution, and post treatment of fabricated membrane. This research proposed the modifications of morphology and surface property of hydrophobic membrane by blending polyethersulfone (PES) with three polymeric additives, polyvinylpyrrolidone (PVP), Pluronic F127 (Plu), and Tetronic 1307 (Tet). PES hollow fiber membranes were fabricated via dry-wet spinning process by using a spinneret with inner and outer diameter of 0.7 and 1.0 mm, respectively. The morphology changes of PES blend membrane by those additives, as well as the change of performance in ultrafiltration module were comparatively observed. The surface structure of membranes was characterized by atomic force microscopy and Fourier transform infra red spectroscopy. The cross section morphology of PES blend hollow fiber membranes was investigated by scanning electron microscopy. The results showed that all polymeric additives blended in this system affected to improve the performances of PES membrane. The ultra-filtration experiment confirmed that PES-PVP membrane showed the best performance among the three membranes on the basis of filtration stability.

• Food Science and Biotechnology
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• 제14권3호
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• pp.380-386
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• 2005

Optimal conditions of ultrafiltration (UF) and nanofiltration (NF) were investigated for separation and concentration of isoflavones and oligosaccharides from Sunmul. Levels of COD, BOD, and suspended solids (SS) in UF and NF permeates were also determined to evaluate effectiveness of these processes for reducing water pollution. Optimal UF operation conditions to achieve minimal fouling and maximal flux were $33-34^{\circ}C$ operating temperature and 2.3-2.4 bar trans-membrane pressure. Recovery yields of isoflavones and oligosaccharides in UF retentate were 11.49-28.16% and 12.77-27.57%, respectively. Increase in volumetric concentration factor (VCF) resulted in more functional compounds of isoflavones and oligosaccharides passing through UF membrane. Total isoflavone and oligosaccharide yields decreased by 3% as VCF increased from 6.0 to 8.0 and from 8.0 to 10.0, while decreased significantly by 10% as VCF decreased from 4.0 to 6.0. Optimal NF operating conditions were 192-195 psig operating pressure at $30-33^{\circ}C$. Total yields of isoflavones and oligosaccharides significantly decreased at VCF 8.0, whereas did not decrease up to VCF 6.0 during NF operation. Therefore, VCF 6.0 was recommended for economical process. COD and BOD decreased by more than 98% after NF process, and SS were not detected after UF process. These results indicated sequential filtration process was useful for separation of isoflavones and oligosaccharides from Sunmul and for reducing water contaminants.

• 청정기술
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• 제9권2호
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• pp.63-69
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• 2003

도금산업은 제조 공정상 다량의 환경오염물질을 배출하는데 일반적으로 산 알칼리 폐수 뿐만아니라 크롬화합물, 시안화합물, 중금속류, 부식성물질, 독성물질 등이 발생하여 환경오염을 초래한다. 본 연구에서는 도금 산업에서 가장 환경오염부하가 크고 많이 적용하는 아연도금공정의 공정진단 및 분석을 통해 아연도금공정의 청정생산 실행효과가 큰 우선순위별 단위공정에 최적기술을 적용하여 현 도금공장의 열악한 근무환경과 환경오염을 개선하고자 하였다.

• Bulletin of the Korean Chemical Society
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• 제27권3호
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• pp.413-418
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• 2006

Sodium hyaluronate (NaHA), water soluble polymer having ultra-high molecular weight, is characterized by using on-line frit inlet asymmetrical flow field-flow fractionation (FI-AFlFFF) and multiangle light scattering (MALS). This study demonstrates the capability of power programming FI-AFlFFF for the separation of NaHA and the applicability of FI-AFlFFF with MALS for the characterization of molecular weight distribution and their structural information. Since sample injection and relaxation in FI-AFlFFF are achieved by using hydrodynamic relaxation, separation of high molecular weight polymers can be achieved smoothly without halting the separation flow. Experiments are carried out with the two different NaHA products (a raw NaHA sample and a thermally degraded NaHA product) and molecular weight distribution and conformations in solution are determined. Influence of sample filtration on the change of molecular weight distribution is also discussed.

• 대한안전경영과학회지
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• 제11권4호
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• pp.111-118
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• 2009

In this study the real situation of apartment house in seoul is reproduced with multi-zone modeling program CONTAM2.4. This model include disinfection system which is consist of dilution, filtration, UVGI(ultra violet germicidal irradiation). It's energy consumption was also analyzed through the linked model of CONTAM and TRNSYS according to the combination of components. The comparison of total energy consumption through energy analysis revealed that adjusting the air change rate of the UVGI air sterilizer to maintain the same indoor microbe removal capability was more advantageous in terms of energy consumption.