• KSBB Journal
• /
• 제8권2호
• /
• pp.178-184
• /
• 1993

Extractive fermentations with the extract of Jerusalem artichoke in an aqueous-two-phase-system of polyethyleneglycol(PEG) and dextran(Dx) were investigated to obtain the effects of composition of PEG and Dx on both fermentation ,characteristics and partition ratio of alcohol. The specific growth rate of K. Fraglis CBS 1555 increased with a decrease of concentration of PEG and Dx. It augmented along with concentration of initial sugar up to 80g/l but decreased thereafter. The specific production rate of alcohol showed a rising tendency up to 100g/lof initial sugar, whereafter represented a decreasing trend. The partition ratio of alcohol between two phases augmented according to decrease of Dx comic. and increase of PEG cone. regardless of initial sugar concentrations. The ratio, however, decreased with Increment of initial sugar concentration at constant composition of PEG and Dx. The partition coefficient of alcohol had an ascending effect to the increase of PEG cone, but it had little effect on the changes of concentrations of Dx and initial sugar. The present study suggests that the optimum composition of PEG and Dx in the aqueous-two-phase-system by extractive fermentation were around 6.5%(w/v) of PEG and 3%(w/v) of Dx in considerations of emulsion state, sedimentation and separation of two phases, alcohol partition ratio, and specific growth rate.

• Membrane and Water Treatment
• /
• 제4권2호
• /
• pp.127-142
• /
• 2013

In order to investigate the significance of "salting-out" and "pore swelling" effects on the nanofiltration of neutral solutes, rejection properties of two NF ceramic and polymeric membranes were studied with single polyethyleneglycol (PEG) solution and mixed PEG/inorganic electrolyte solutions. For both membranes, the rejection rate of PEG was found to decrease significantly in the presence of ions. In the case of the ceramic membrane (rigid pores), this phenomenon was imputed to the sole partial dehydration of PEG molecules induced by the surrounding ions. This assumption was confirmed by the lowering of the PEG rejection rates which followed the Hofmeister series. Experimental data were used to compute the resulting decrease in the Stokes radius of PEG molecules in the presence of the various salts. Concerning the polymeric membrane, the decrease in the rejection rate was found to be systematically higher than for the ceramic membrane. The additional decrease was then ascribed to the swelling of the pores. The experimental data of rejection rates were then used to compute the variation in the mean pore radius in the presence of the various salts. The pore swelling phenomenon due to accumulation of counterions inside pores was supported by electrokinetic charge density measurements.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2013년도 춘계학술대회 논문집
• /
• pp.809-809
• /
• 2013

We report a new method for highly controllable local patterning of a hydrogel on microfabricated cantilevers and fabrication of all hydrogel microcantilevers. We constructed a dynamic mask based photolithography setup using a commercial beam projector, a 3-axis microstage and other optical components. Dynamic masks generated from the beam projector controlled the shape, size, and position of hydrogel patterns while the 3-axis microstage mainly controlled the thickness of hydrogel patterns and hydrogel microcantilevers. Using the constructed setup, polyethyleneglycol diacrylate (PEGDA) was patterned on microfabricated cantilevers in a highly controlled manner. Currently, the smallest PEGDA patternable is a 5-${\mu}m$-diameter circle with a thickness of ~$10{\mu}m$. To confirm thicknesses of patterned PEGDAs on silicon microcantilevers, resonance frequencies of microcantilevers were measured before and after each PEGDA patterning. Thicknesses extracted from resonance measurements showed good agreement with measurements using an optical microscope. In addition, PEGDA microcantilevers with various dimensions and thicknesses were fabricated on glass and silicon substrates. Surfaces of fabricated all hydrogel microcantilevers were flat enough to facilitate other post processing and to be used for various sensing applications.

• 공업화학
• /
• 제3권4호
• /
• pp.620-626
• /
• 1992

Ironpentacarbonyl에 의한 니트로벤젠의 환원반응에 PEG를 상이동 촉매로 사용한 결과 상온에서 90% 이상의 아닐린 수율을 얻을 수 있었다. 니트로벤젠의 반응속도는 PEG의 사슬길이와 결합점의 수에 의존하였으며 NaOH의 농도가 높고 용매의 극성이 커질수록 증가하였다. 그러나 아닐린의 수율은 NaOH농도가 2N일때 최대였으며 그 이상의 농도에서는 감소하였다

• 한국추진공학회지
• /
• 제2권3호
• /
• pp.62-69
• /
• 1998

Polycaprolactone (PCP)과 coupling agent로 silane 유도체를 polyethylene glycol(PEG)/cyclo-tetramethylene tetranitramine(HMX) 추진제에 첨가하였을 때 추진제의 기계적 특성 변화를 연구하였다. PEG의 일부를 Polycaprolactone(PCP)으로 대체 사용하면 추진제의 기계적 성질은 증가하였으며, PCP/HMX 추진제는 PEG/HMX보다 최대 인장 강도가 17%, 최대 응력하의 신율은 59% 증가하였다. 그러나 PCP함량이 증가할수록 수분에 대한 안정성은 저하됨을 $40^{\cire}C$의 온도와 90% 상대 습도 분위기에서 보관된 추진제의 경도 변화와 PEG/PCP바인더의 부피 팽윤 실험에 의해 알 수 있었다. 또한 PEG/PCP/HMX 추진제를 $60^{\cire}C$에서 가속 노화시키면 triethoxysilyl propionitrile(TESPN)과dinitrosalicylic acid((DNSA) 함량이 증가할수록 추진제의 경도가 감소하는 것으로 나타났다.

• 접착 및 계면
• /
• 제3권1호
• /
• pp.13-19
• /
• 2002

We have studied on the surface and adhesion properties for acrylic terpolymers, having both hydrophobic and hydrophilic side chains, synthesized via solution polymerization. In order to develop a waterborne material. we tried to synthesize these terpolymers via emulsion polymerization. The polymeric emulsion synthesized was mainly composed of methyl methacrylate (MMA), methoxy-polyethyleneglycol methacrylate (MPEGMA) having hydrophilic side chains and methoxypolypropyleneglycol methacrylate (MPEGMA) having hydrophobic side chains. The viscosities of this series increased with an increase in the content of the co-monomer such as MPEGMA and (MPEGMA). This behavior resulted in the increase in the diameter and heterogeneity of the emulsion particle via AFM observation. Furthermore. the tensile adhesion strength and 90-degree peel strength of the adhesive of these polymeric emulsions were measured. In the case of polymeric emulsion composed of the same content of both hydrophilic and hydrophobic component, the adhesion property showed the highest value. However, since the adhesion properties as a practical applicable adhesive were poor, some improvements were required. When the composition above was modified with butyl acrylate (BA), the improvement effect on adhesion strength was accepted. In particular, 90-degree peel strength increased up to a maximum of 400% of the original value.

• 한국동물학회지
• /
• 제25권3호
• /
• pp.115-122
• /
• 1982

소의 혈장으로부터 알부민을 순수 정제하였으며 순도는 면역 화학적 방법을 사용하여 확인하였다. 정제된 알부민에 maleate, iodoacetate, iodoacetamide 및 glutathione의 4가지 thiol 화합물을 각각 반응시켜 그 복합체를 9가지의 상이한 완충용액내에서 초산셀룰로우즈 전기영동한 결과 barbital buffer와 Na-acetate buffer를 제외한 다른 완충용액내에서 albumin-glutathione 복합체는 두 가지의 단백질로 분리되었으며 pH 4.8 citrate buffer 및 pH 4.8 succinate buffer내에서 albumin-iodoacetate 및 albumin-iodoacetamide 복합체는 두 가지의 단백질로 분리되었다. 전기영동상에 나타나는 알부민 분획에는 conformation이 서로 다른 두 가지 이상의 알부민 분자가 존재한다고 사료된다.

• 공업화학
• /
• 제21권4호
• /
• pp.463-468
• /
• 2010

콘크리트 유동화제로 사용되는 polycarboxylate 계 콘크리트 유동화제를 합성하였다. 합성에 있어서 친수기인 polyethylene oxide 부가몰 및 분자량에 따른 합성된 유동화제의 물성 및 이의 콘크리트 몰타르에 미치는 영향을 조사하였다. 합성원료로서 methoxy-polyethyleneglycol 및 methacrylic acid의 종류, methacrylic acid 부가량, 개시제 종류 및 양에 따른 graft 공중합 조건에 따라 얻어진 PC의 물성 및 이가 모르타르에 미치는 영향을 조사하였다. 물성으로는 PC 수용액의 계면물성, 시멘트 입자의 젖음성, 몰타르의 유동성 및 최종 콘크리트의 강도 등을 측정하였다. 합성된 PC는 수용액에 대한 표면장력 값이 작을수록 시멘트 입자에 대한 젖음성이 우수할수록 우수한 모르타르 유동성을 보였으며 콘크리트의 강도가 높았다. 본 연구 조건에서는 MPEG 대비 MA 함량이 1.3 정도일 경우 그리고 개시제가 KSP일 경우에 합성된 PC가 가장 적합하였다.

• 한국미생물·생명공학회지
• /
• 제16권3호
• /
• pp.175-181
• /
• 1988

섬유소 기질로부터 L-lysine을 생산할 목적으로 Cellulomonas flavigena에 Brevibacterium flavum 및 Corynebacterium glutamicum을 각각 이속간 원형질체 융합을 하여 융합조건과 융합체의 성질을 조사하였다. 각각의 parental protoplast를 동량으로 혼합한 후 30% PEG 6000으로 3$0^{\circ}C$, 30분간 융합시킨 결과 1.9$\times$$10^{-6}$~2.1$\times$$10^{-6}$의 융합빈도를 얻었고, 134주의 융합체 중 유전적 안정화가 판명되고 CMC 기질로부터 L-lysine 생성능이 인정된 FCB 3 및 FCC 19를 최종 선별하였다. FCB 3 및 FCC 19는 친주보다 DNA 함량이 높을 분 아니라 G＋C 함량도 융합전 친주의 G＋C 총함량의 약 1/2에 해당하여 반수체로서 안정화되어 있었으며, 그리고 친주와 반대로 CMC 자화능이 있어 CMC로부터 L-lysine을 배지 중에 축적하였다.

• 한국의류학회지
• /
• 제25권5호
• /
• pp.925-932
• /
• 2001

The influence of ultraviolet(UV)-ray in sun light on human skin has been noted. Textiles can provide protection against harmful UV-radiation. Normally UV-absorbing finishes are used to get better protection. The purpose of this study is to evaluate the UV-cut properties of cotton fabrics treated with UV-absorber. 2,2-dihydroxy-4,4-dimethoxbenzophenone, as UV-absorber was applied to 100% cotton fabric. Reagents added in finishing solution were Triton X-100, polyethylene glycol 400, and $MgCl_2{\cdot}6H_2O$, and C.I. Direct Red 81. Both untreated and treated cotton fabrics were exposed to a xenon arc lamp for 20 and 80 hours. UV absorption spectra of finishing solutions and UV transmission spectra of fabrics were measured by the UV/VIS spectrophotometer. The results of this study can be summarized as follows. The results of this study can be summarized as follows. Absorption and the related transmission spectra were modified in a controlled way with UV-absorber. Absorption effect of UV-absorber was improved by adding Triton X-100, PEG 400, and $MgCl_2{\cdot}6H_2O$ in finishing solution. The UV absorption of finishing solution was in the following order: U/D/T/P/M>D/T/P/M> D/T> D/P, D>U/T/P/M>U/T>T/P/M>T. The UV transmittance of cotton fabrics was remarkably decreased by the application of UV-absorber and additives. The UV-cut properties were most improved by the application of U/D/T/P/M.