• Membrane and Water Treatment
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• 제10권6호
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• pp.461-469
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• 2019

In the present work, we present a new effective hydrophilicity modifier for polysulfone (PSf) membrane. Firstly, amphiphilic nanocellulose (ANC) with different substitution degrees (SD) was synthesized by esterification reaction with nanocellulose (NC) and dodecyl succinic anhydride (DDSA). The SD and morphology of ANC were characterized by titration method and transmission electron microscopy (TEM). Then, the polysulfone (PSf)/ANC blend membranes were prepared via an immersion phase inversion method. The influence of SD on the morphology, structure and performances of PSf/ANC blend membrane were carefully investigated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), mechanical property test, contact angle measuring instrument and filtration experiment. The results showed that the mechanical property, hydrophilicity and anti-fouling property of all the PSf/ANC blend membranes were higher than those of pure PSf membrane and PSf/NC membrane, and the membrane properties were increased with the increasing of SD values. As ANC-4 has the highest SD value, PSf/ANC-4 membrane exhibited the optimal membrane properties. In conclusion, the prepared ANC can be used as an additive to improve the hydrophilicity and anti-fouling properties of polysulfone (PSf) membrane.

• 멤브레인
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• 제27권3호
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• pp.273-283
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• 2017

폴리술폰 고분자는 비대칭 정밀여과 멤브레인 제조에 가장 널리 사용되는 고분자 소재이다. 폴리술폰 멤브레인은 소수성 특성으로 인하여 공정상에서 빠른 막오염이 일어난다. 고분자 블렌딩은 폴리술폰 멤브레인의 수명을 향상시키는데 있어 가장 간단하고 효과적인 방법이다. sPES는 폴리술폰 블렌딩 방법을 통하여 소수성을 해결할 수 있는 유용한 친수성 고분자이다. 본 연구에서는 PSF/sPES/DMF/PVP/BE 고분자 용액을 물에 침지시켜 정밀여과 멤브레인을 제조하였다. 캐스팅 용액에 소량의 sPES 첨가함으로써 정밀여과 멤브레인 구조 변화를 볼 수 있었다. sPES의 첨가는 높은 비대칭성과 활성층의 성장, 그리고 평균 기공 크기의 감소를 가져왔다. 하지만 수투과량은 PSF/sPES/DMF/PVP/BE로 만든 멤브레인이 PSF/DMF/PVP/BE로 만든 멤브레인에 비해 더 큰 값을 보였다.

• 공업화학
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• 제29권3호
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• pp.264-269
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• 2018

Polysulfone (PSf)에 탄소 나노 튜브(CNTs, carbon nano tubes)와 두 가지 추출제, di-(2-ethylhexyl)-phosphoric acid (D2EHPA)와 tributyl phosphate (TBP)를 고정화시킨 PSf/D2EHPA/TBP/CNTs 비드를 제조하였다. 제조한 비드의 특성은 SEM, TGA 및 FTIR로 분석하였다. 제조한 PSF/D2EHPA/TBP/CNTs 비드에 의한 Sr(II)의 제거속도는 유사 2차 속도식에 의해 잘 설명되었으며, Langmuir 등온식으로 구한 Sr(II)의 최대 제거 용량은 5.52 mg/g이었다. 본 연구에서 제조한 PSf/D2EHPA/CNTs 비드에 의한 Sr(II)의 제거효율은 TBP가 첨가되지 않은 PSf/D2EHPA/CNTs 비드에 의한 Sr(II)의 제거효율 보다 크게 향상되는 결과를 나타내었다.

• 전자공학회논문지S
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• 제36S권2호
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• pp.57-62
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• 1999

점확산 함수(point spread function: PSF)의 정확한 주정은 복원결과가 원 영상에 얼마나 근접할 수 있는가를 결정한다는 점에서 영상처리의 중요한 연구 주체중의 하나가 된다. 본 논문에서는 PSF를 추정하기 위한 새로운 알로리즘을 제안하고, 이를 영상복원에 적용한 후 이를 기반으로 완전 디지털 자동초점 시스템을 제안한다. 자동초점시스템을 구현하기 위한 과정은 두 단계로 구성되어 있는데, 즉 에지 분류을 통한 PSF측정과, 이를 이용한 영상복원이다. 보다 구체적으로, 입력 영상을 다수의 소 영상 혹은 블록으로 분할한 뒤, 에지를 포함하고 있는 블록들로부터 단위계단응답을 구하여 평균한 후, 2차원 등방성 PSF를 추정한다. 마지막으로 추정된 PSF를 사용하여 영상복원을 수행함으로써 맞는 영상을 구한다.

• Macromolecular Research
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• 제10권4호
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• pp.209-214
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• 2002

Miscibility of polysulfone (PSf) with various hydrophilic copolymers was explored. Among these blends, PSf gives homogeneous mixtures with poly(1-vinylpyrrolidone-co-styrene) copolymers [P(VP-S)] when these copolymers contained VP from 68 to 88 wt%. Microporous membranes for the ultrafiltration process were prepared from PSf blends with P(VP-S) copolymers. The membranes prepared from the PSf/(VP-S) blends exhibited higher water flux than the membranes prepared from PSf irrespective of the VP content. The solute rejection examined with the membranes fabricated from the miscible blends was similar to that of PSf membrane. However, the solute rejection examined with the membranes fabricated from the immiscible blends was lower than that of PSf membranes.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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• pp.7-10
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• 2003

This paper proposes the multiple objects focusing algorithm. Given multiple objects at different distances from a camera, we assume that one object is well-focused and the others are out-of-focused. The proposed auto-focusing algorithm is summarized as follows: (i) detects edges from an input image, (ⅱ) estimates the radius of PSF (Point Spread Function) across the edge, (ⅲ) gather edge points having same radius of PSF, (ⅳ) segments the image into regions with the same radius of PSF, and (ⅴ) restores the each segmented region using the corresponding PSF.

• Current Research on Agriculture and Life Sciences
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• 제24권
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• pp.23-27
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• 2006

육묘 생력화를 위한 적정 부직포규격을 선발하기 위하여 경상북도 농업기술원 시험포장에서 4월 20일부터 6월 1일 까지 파종기를 달리하여 부직포 규격별로 온도변화, 묘소질, 육묘 노동력 및 자재비 절감효과 등을 조사하였다. 부직포 규격별 묘생육은 부직포두께가 두꺼울수록 초장은 커지고, 엽수와 지상부건물중은 감소하였다. 부직포 규격별 매트형성 정도는 4월 파종구는 $40g/m^2$과 $60g/m^2$의 부직포 피복구에서 비닐피복과 같이 양호하였으나 $80g/m^2$과 $100g/m^2$은 불량하였으며, 6월 1일 파종구에서는 $40g/m^2$ 의 부직포 피복구에서만 매트형성이 양호하였고 그 외 부직포 규격 및 비닐터널피복에서는 불량하게 나타났다. 모의 지상부 생육특성 및 매트형성정도에서 1모작인 4월파종구의 경우는 $40g/m^2$와 $60g/m^2$의 부직포가, 2모작인 6월파종구에서는 $40g/m^2$ 의 부직포가 묘생육에 가장 적합한 것으로 조사되었다.

• 한국축산식품학회지
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• 제36권3호
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• pp.335-342
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• 2016

The object in this study is to investigate the effects of high pressure and freezing processes on the curdling of skim milk depending on the presence of transglutaminase (TGase) and glucono-δ-lactone (GdL). Skim milk was treated with atmospheric freezing (AF), high pressure (HP), pressure-shift freezing (PSF) and high pressure sub-zero temperature (HPST) processing conditions. After freezing and pressure processing, these processed milk samples were treated with curdling agents, such as TGase and GdL. Pressurized samples (HP, PSF and HPST) had lower lightness than that of the control. In particular, PSF had the lowest lightness (p<0.05). Likewise, the PSF proteins were the most insoluble regardless of whether they were activated by TGase and GdL, indicating the highest rate of protein aggregation (p<0.05). Furthermore, the TGase/GdL reaction resulted in thick bands corresponding to masses larger than 69 kDa, indicating curdling. Casein bands were the weakest in PSF-treated milk, revealing that casein was prone to protein aggregation. PSF also had the highest G' value among all treatments after activation by TGase, implying that PSF formed the hardest curd. However, adding GdL decreased the G' values of the samples except HPST-treated samples. Synthetically, the PSF process was advantageous for curdling of skim milk.

• 상하수도학회지
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• 제34권2호
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• pp.127-137
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• 2020

In this study, a MWCNT(multi-wall carbon nanotube) was added to polysulfone(PSf) support layer to improve flux of TFC(thin film composite) RO(reverse osmosis) membrane. Two different kinds of MWCNT were used. Surfaces of some MWCNTs were modified hydrophilically through acid treatment, while those of other MWCNTs were modified through heat treatment to maintain their hydrophobicity. MWCNT/PSf support layer was prepared by adding PSf to the NMP mixed solvent containing 0.1 wt% MWCNTs using a phase inversion method. The surface porosity of the MWCNT/PSf support increased by 42~46% while its surface pore size being maintained. The TFC RO membrane made of MWCNT/PSf support layer showed a 20% flux increase while its salt rejection characteristics is sustained. In addition, the MWCNT/PSf support layer has better mechanical stability than the PSf support layer, there resulting in an increased resistance of flux reduction due to physical pressure.

• 한국환경과학회지
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• 제25권11호
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• pp.1485-1491
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• 2016

PSf/D2EHPA/CNT beads were prepared by immobilizing di-(2-ethylhexyl)-phosphoric acid (D2EHPA) and carbon nanotubes (CNT) on polysulfone (PSf) and used to remove Cu(II) from aqueous solutions. Optimum pH was in the range of 4 to 6. The removal kinetic of Cu(II) by the prepared PSf/D2EHPA/CNT beads was mainly governed by internal diffusion, and the diffusion coefficient of Cu(II) by PSf/D2EHPA/CNT beads was found to be $2.19{\times}10^{-4}{\sim}2.64{\times}10^{-4}cm^2/s$. The Langmuir isotherm model predicted the experimented data well. The maximum removal capacity of Cu(II) obtained from this isotherm was 7.32 mg/g. Calculated thermodynamic parameters such as ${\Delta}G^o$, ${\Delta}H^o$ and ${\Delta}S^o$ showed that the adsorption of Cu(II) ions onto PSf/D2EHPA/CNT beads was feasible, spontaneous and endothermic at 293-323 K.