• Korean Chemical Engineering Research
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• 제58권4호
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• pp.524-529
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• 2020

고분자전해질 연료전지의 기계적 내구성을 높이기 위해 고분자막에 지지체를 넣은 강화막이 사용되고 있다. 지지체는 주로 e-PTFE를 사용하는데 소수성이고 이온전달이 안되므로 성능저하의 원인이 될 수 있다. 그래서 본 연구에서는 e-PTFE 지지체가 PEMFC 성능과 전기화학적 내구성 미치는 영향에 대해 연구하였다. 본연구에서는 지지체가 들어간 강화막과 들어가지 않은 단일막(비강화막)을 비교하였는데, 지지체의 소수성 때문에 강화막의 물 확산계수가 단일막보다 낮았다. 강화막은 물확산 계수가 낮아 이온의 막 이동 저항이 단일막보다 높았다. 지지체의 낮은 수소투과도 때문에 강화막의 OCV가 단일막보다 높았다. 지지체가 수소투과도를 감소시킴으로서 라디칼 발생속도를 감소시켜 강화막의 전기화학적 내구성도 향상시킴을 보였다.

• 대한통합의학회지
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• 제2권2호
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• pp.41-47
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• 2014

Purpose : The aim was to compare the implant success rate according to membrane type through a clinical case of patients, who used bio-resorbable membrane and non-resorbable membrane. Methods : A survey was conducted targeting patients with the use of bio-resorbable membrane and non-resorbable membrane who visited H dental clinic in Busan for implant surgery and bone graft for 1 year from May 2010 to May 2011. A chart was made and surveyed for 100 people with non-resorbable membrane and for 75 people with bio-resorbable membrane. Results were compared. Results : 1. As for the measurement value of Periotest M${(R)}$, the value of -8~0 was measured with 92% in case of surgery by using non-resorbable membrane. The value of +1~+9 was measured with 8.0%. In case of surgery by using bio-resorbable membrane, Peiotest M(R) was measured with 78.7% as for the value of -8~0 and 16(21.3%) as for the value of +1~+9. In light of this, a case of using non-resorbable membrane was indicated to be higher(p=0.021) in success rate than a case of using bio-resorbable membrane. 2. As a result of periodontal conditions, namely, bleeding(p=0.914), swelling(p=0.500), inflammation(p=0.074), pain(p=0.571), and itch appearance(p=0.475) according to membrane type, all were insignificant. Conclusions : A case of using non-resorbable membrane is considered to be likely to be more effective than using bio-resorbable membrane during GBR(Guided Bone Regeneration) with the use of membrane in implant surgery.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제26권2호
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• pp.146-153
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• 2000

The purpose of present study is comparing the effect of Teflon Membrane and Nylon Membrane on bone regeneration in rabbit tibia. The 6 defects of $8{\times}8{\times}5mm$ size were drilled with dental handpiece in rabbit tibia, which on left side as an order of Control group(no coverage), Group 1(Nylon $5{\mu}m$ size), Group 3(Nylon $10{\mu}m$ size), and on right side Control group, Group 2($5{\mu}m$ Teflon), Group 4($10{\mu}m$ Teflon). Animals were killed at 7, 10, 14, 42 days to make specimens and observed the difference of healing potentials with light microscopy. The results were as follows ; 1. New bone formation has taken place at 14 days in Guided Bone Regeneration (GBR) group comparing to the Control group of massive inflammatory status. 2. Larger pore membrane allows more favorable healing potentials. Bone formation started earlier in larger membrane pore groups than smaller groups, until 14 days. 3. Bone forming potentials of Teflon membrane group was higher than Nylon membrane groups, Control group has the lowest bone forming potentials. 4. New bone formation was almost ended in 42 days, and there was no difference of bone formation between Nylon and Teflon membrane group of different size. There was no difference of bone formation at final stage(42 days) between Nylon membrane and Teflon membrane of same pore size. So nylon membrane may be clinically usable in guided bone regeneration case with further studies.

• The Journal of Advanced Prosthodontics
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• 제7권6호
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• pp.484-495
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• 2015

PURPOSE. This study was to evaluate the effects of bacterial cellulose (BC) membranes as a barrier membrane on guided bone regeneration (GBR) in comparison with those of the resorbable collagen membranes. MATERIALS AND METHODS. BC membranes were fabricated using biomimetic technology. Surface properties were analyzed, Mechanical properties were measured, in vitro cell proliferation test were performed with NIH3T3 cells and in vivo study were performed with rat calvarial defect and histomorphometric analysis was done. The Mann-Whitney U test and the Wilcoxon signed rank test was used (${\alpha}<.05$). RESULTS. BC membrane showed significantly higher mechanical properties such as wet tensile strength than collagen membrane and represented a three-dimensional multilayered structure cross-linked by nano-fibers with 60 % porosity. In vitro study, cell adhesion and proliferation were observed on BC membrane. However, morphology of the cells was found to be less differentiated, and the cell proliferation rate was lower than those of the cells on collagen membrane. In vivo study, the grafted BC membrane did not induce inflammatory response, and maintained adequate space for bone regeneration. An amount of new bone formation in defect region loaded with BC membrane was significantly similar to that of collagen membrane application. CONCLUSION. BC membrane has potential to be used as a barrier membrane, and efficacy of the membrane on GBR is comparable to that of collagen membrane.

• 한국막학회:학술대회논문집
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• 한국막학회 1998년도 추계 총회 및 학술발표회
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• pp.15-18
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• 1998

Membrane reactors are systems which combine a chemical reactor with a membrane separation process allowing to carry out simultaneously conversion and product separation. The catalyst can be immobilized on the membrane or simply compartmentalized in a reaction space by the membrane. Membrane reactors are today investigated to produce optically pure isomers and/or resolve racemic mixture of enantiomers. The interest towards these systems is due to the increasing demand of enantiomerically pure compounds to be used in the pharmaceutical, food, and agrochemical industries. In fact, enantiomers can have different biological activities, which often influence the efficacy or toxicity of the compound. On the basis of current literature there are basically two schemes on the use of membrane technology to produce enantiomers. In one case, the membrane itseft is intrinsically enantioselective: the membrane is the chiral system which selectively separates the wanted isomer on the basis of its conformation. In the other, a kinetic resolution using an enantiospecific biocatalyst is combined with a membrane separation process; the membrane separates the product from the substrate on the basis of their relative chemical properties (i.e. solubility). This kind of configuration is widely used to carry out kinetic resolutions of low water soluble substrams in biphasic membrane reactors [Giomo, 1995, 1997; Lopez, 1997]. These are systems where enzyme-loaded membranes promote reactions between two separate phases thanks to the properties of enzymes, such as lipases, to catalyse reactions at the org ic/aqueous interface; the two phases are maintained in contact and separated at the membrane level by operating at appropriate transmembrane pressure. A schematic representation of biphasic membrane reactor is shown in figure 1, while an example of enantiospecific reaction and product separation carried out with these systems is reported in figure 2.

• 멤브레인
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• 제31권1호
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• pp.52-60
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• 2021

SPG (Shirasu porous glass) 원통형 막을 회전 시키는 회전 막유화를 사용하여 칼슘 알지네이트 미소 구체를 제조할 때, 단분산 미소 구체를 제조하기 위한 회전 막유화 공정변수들의 최적 조건을 결정하였다. 회전 막유화의 공정 변수로는 막의 회전 속도, 막간 압력차, 연속상에 대한 분산상의 비율, 알지네이트 농도, 유화제의 농도, 안정제 농도, 가교제 농도 및 막의 세공 크기를 설정하고, 이들 변수로 제조된 알지네이트 미소 구체의 크기와 단분산성에 미치는 영향을 검토하였다. 이 결과 회전 막유화의 공정 변수들 중에서 막모듈의 회전 속도, 유화제의 농도, 가교제의 농도가 증가 할수록 미소 구체의 크기가 감소하였으며, 반면에 연속상에 대한 분산상의 비율, 막간 압력차, 알지네이트 농도가 증가할수록 미소 구체의 크기가 증가하였다. 세공 크기 3.2 ㎛인 SPG막을 사용한 회전 막유화에서 공정변수 조절을 통해 최종적으로 입자 크기가 4.5 ㎛의 단분산 알지네이트 미소 구체의 제조가 가능하였다.

• 한국막학회:학술대회논문집
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• 한국막학회 1991년도 춘계 총회 및 학술발표회
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• pp.5-8
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• 1991

Membrane techology is reapidly replacing and/or augmenting the traditional separation processes in many industries. In some cases, it opens new markets. Research and development in academia and industry have proven that the new technology is cost effective and viable. The future of membrane technology looks bright.

• 한국막학회:학술대회논문집
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• 한국막학회 2003년도 The 4th Korea-Italy Workshop
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• pp.73-76
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• 2003

No Abstract, See Full Text

• Maxillofacial Plastic and Reconstructive Surgery
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• 제36권6호
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• pp.239-246
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• 2014

Many kinds of membrane have been used for the guided bone regeneration (GBR) technique. However, most membranes do not fulfill all requirements for the ideal membrane for the GBR technique. Among them, collagen membrane has been most widely used. However, its high price and weak tensile strength in wet condition are limitations for wide clinical application. Synthetic polymers have also been used for the GBR technique. Recently, silk based membrane has been considered as a membrane for the GBR technique. Despite many promising preclinical data for use of a silk membrane, clinical data regarding the silk membrane has been limited. However, silk based material has been used clinically as vessel-tie material and an electrospun silk membrane was applied successfully to patients. No adverse effect related to the silk suture has been reported. Considering that silk membrane can be provided to patients at a cheap price, its clinical application should be encouraged.

• Membrane and Water Treatment
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• 제6권5호
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• pp.379-392
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• 2015

Polyvinyl chloride (PVC) ultrafiltration membrane was prepared by blending 12 wt.% of PVC in N, N-dimethylacetimide (DMAc) with polyethylene glycol 400 (PEG400) as an additive. The influence of PEG400 concentration on the PVC membrane morphology, permeability, fouling and rejection were investigated. Fouling and rejection of the PVC membrane were characterized by dextran T-100 filtration. The results showed that membrane water flux was increased up to $682Lm^{-2}h^{-1}$ when 28 wt.% of PEG400 was added into the PVC membrane solution. The best membrane performance with a low fouling and a high selectivity was achieved by adding 12 wt.% concentration of PEG400, which resulted in 90% rejection of dextran and 90% of flux recovery ratio. At further addition of PEG400 concentration, irreversible fouling was starting to increase. A 90% of irreversible fouling was formed in the PVC membrane when more than 22 wt.% of PEG400 is added.