• 대한화학회지
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• 제28권6호
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• pp.349-354
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• 1984

요오드화알칼리금속(NaI, KI, RbI, CsI)의 상대점도와 삼투 계수를 메탄올, 에탄올, dimethylsulfoxide (DMSO), and sulfolane (TMS) 용액에서 각각 측정하였다. 각 용매에서 요오드화 알칼리금속의 점도 A계수는 MeOH > EtOH > TMS > DMSO의 순위이고, 점도 B계수는 TMS > EtOH > DMSO > MeOH의 순위이다. 또 양성자성용매인 MeOH과 EtOH에서는 dB/dT의 순위가 NaI > KI > RbI > CsI이나, 비양성자성용매인 DMSO와 TMS에서는 반대순위이다. 한편 모든 용액에서 전해질의 삼투 계수는 Raoult 법칙의 양의 벗어남으로 인해 농도증가에 따라 삼투계수는 감소하였다. 각용매에서의 전해질의 삼투계수가 커지는 순위는 EtOH > DMSO > MeOH > TMS이다. 이러한 사실로 부터 요오드화알칼리금속은 양성자성용매와 비양성자성용매에서의 용매화현상이 매우 다르며, 이온쌍형성 및 용매의 구조파괴현상 등이 있음을 알았다.

• 한국응용과학기술학회지
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• 제29권2호
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• pp.205-213
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• 2012

본 연구에서는 편백나무 잎 추출물의 에틸아세테이트 분획을 함유한 크림의 안정성을 평가하였다. 다양한 저장 온도($4^{\circ}C$, $25^{\circ}C$, $37^{\circ}C$ 및 $45^{\circ}C$) 및 태양광선에의 노출 하에서 12주 동안 추출물 함유 크림의 pH, 점도 및 흡광도 변화를 측정하였다. 위에서 언급된 온도별 저장조건에서 추출물이 함유되어 있지 않은 대조군 크림은 pH 변화가 거의 없었다. 추출물 함유 크림의 경우는 $4^{\circ}C$와 $25^{\circ}C$에서 pH가 평균 0.11 감소하였고, $37^{\circ}C$, $45^{\circ}C$ 저장과 태양광선 노출 시는 각각 0.55, 0.84 및 0.59 감소하였다. 온도별 저장 조건에서 12주 후 추출물 함유 크림과 대조군 크림의 점도를 측정하였다. 추출물 함유 크림은 초기 점도보다 평균 2,404 cPs 감소를 나타내었고, 대조군은 평균 1,296 cPs 감소하였다. $45^{\circ}C$ 조건에서 대조군은 12주 후 점도가 1,915 cPs로 감소되었지만, 동일 조건에서 추출물 함유 크림의 점도는 3,810 cPs 감소하였다. 12주 동안 $4^{\circ}C{\sim}37^{\circ}C$에서 추출물 함유 크림의 흡광도 변화는 거의 없었다. 반면에 $45^{\circ}C$ 저장과 태양광선 노출시킨 경우는 흡광도는 각각 32.5 % 및 35.2 % 감소하였다. 크림으로부터 추출물을 용출시킨 에탄올 용액을 태양광선에 직접 노출시켰을 때 4주 만에 흡광도가 54.8 %감소한 것에 비해서는 작은 감소를 나타낸다. 이는 추출물크림이 크림 내에서 비교적 안정화되어 있음을 나타낸다. 추출물 함유 크림과 대조군 크림은 12주 동안 동일한 실험 조건에서 변취나 변색이 나타나지 않았으며, 크리밍이나 응집과 같은 현상은 관찰되지 않았다. 이러한 결과들로부터 편백나무 잎 추출물을 함유한 크림이 비교적 안정함을 확인하였다. 하지만, 추출물 함유 크림을 장기간 저장할 때 안정성은 아직 확실치는 않으며, 추출물을 화장품에 응용하기 위해서는 더 많은 연구가 필요하다고 사료된다.

• Tribology and Lubricants
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• 제25권5호
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• pp.324-329
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• 2009

In this study a complex design fitness analysis of journal bearings is carried out for the LPLi rotary-vane fuel pump application, as an external and horizontal installation, in LPG vehicles. Bearings considered in the analyses are plain and 3-axial groove journal bearings. Upon reflecting the fact that the primary failure mode of bearings in the application is a premature friction and wear failure of bearing metal due to a very low viscosity of liquid fuel LPG as a bearing lubricant, the performance factors of bearings used in an evaluation process of design fitness are a load carrying capacity and vibration suppression ability relative to a rated speed. At this time the design variables of bearings are a radial clearance and length. Results show that, in terms of both of the load carrying capacity and vibration suppression ability, the plain journal bearings are superior to the 3-axial groove journal bearings and among the plain bearings the smaller the bearing clearance (5>10>$15\;{\mu}m$) is and the longer the bearing length (6<8<10<12<14 mm) is, the better the bearing performance is.

• 한국임상수의학회지
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• 제8권1호
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• pp.11-26
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• 1991

The effects of intra-articula. sodium hyaluronate(SH) and polysulfated glycosaminoglycan(PSGAG) on degenerative joint disease of the carpus were compared each other In 20 racehorses. Ten horses were dosed with intra-articula. injection of 20mg SH(2 times/2 weeks interval) and ten horses were dosed with intra-articular injection of 250mg of PSGAG(4 times/1 week into.val). Synovial fluid analysis and clinical examination were made to evaluate the effects of the drugs on degenerative joint disease at before injection and 2 weeks after the last injection, respectively. Appearance and mucinous precipitate quality oi synovial fluids of the group injected with 58 and PSGAG were improved by 40～50% and 60～80%, respectively. The chemical values of alkaline phosphatase, lactic dehydrogenase, aspartate aminotransferase, total protein, A/G ratio and glucose of synovial fluid in the group injected with PSGAG were more clearly returned to the normal values than those of the group injected with SH. Relative viscosity and total white blood cells of synovial fluid were returned to the normal walues after the treatments in both groups. Clinical symptoms(swelling, heat and pain on carpal joint, and lameness) of the horses in the group injected with SH and PSGAG were disappeard by 56～67% and 67～80%, respectivelty. Conclusively, the PSGAG was superior to SH in the effects on treatment of the degenerative joint disease in the horses.

• 한국식품과학회지
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• 제20권6호
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• pp.834-839
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• 1988

쌀전분에 미치는 쌀지질의 영향을 살펴보기 위하여 극성용매인 85% 메탄올로 탈지처리한 전분 시료 및 탈지 후 1% palmitic acid를 첨가한 시료를 제조하여 이화학적 성질을 생전분과 비교 검토하였다. 탈지에 의해 아밀로오스 함량이 다소 높게 나타났으며, 광투과도, 팽화력 및 용해도는 생전분과 지방산 첨가전분은 2단거동을 나타내었으나 탈지에 의해 소실되었다. X-선 회절양상은 전형적인 A형을 나타내었으나, 탈지처리에 의해 상대결정도는 감소하였으며, 지방산 첨가로 상대결정도는 증가하였다. 아밀로그라프에 의한 호화양상은 탈지에 의해 최고점도와 break down이 소실되었으며 set back은 증가하는 경향을 보였고 지방산 첨가로 다시 생전분과 비슷한 특성을 나타내었다.

• 한국식품과학회지
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• 제39권5호
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• pp.527-533
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• 2007

To investigate the optimum ratio of sucrose replacement with high intensity sweeteners, the sensory characteristics and consumer acceptability of coffee drinks containing sucralose and acesulfame-K were studied using descriptive analysis and consumer testing. The relative sweetness of the sucralose and acesulfame-K to sucrose were 600-700 and 200-400 times greater, respectively, within the coffee drink system. The sucrose-replaced coffee drinks containing 100% sucralose, as well as mixtures of sucralose/acesulfame-K in ratios of 75/25 and 50/50, showed sensory profiles that were more similar to those of the original 100% sucrose coffee drink, which had a greater sweet taste, vegetable cream, caramel flavor, viscosity, and mouthcoating. These samples were not different from the 100% sucrose sample in terms of overall consumer acceptability.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.848-854
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• 2006

In this study, a computational analysis system has been developed in order to investigate flow-induced vibration(FIV) phenomenon for general stator-rotor cascade configurations. Relative movement of the rotor with respect to stator is reflected by modeling independent two computational domains. Fluid domains are modeled using the unstructured grid system with dynamic moving and local deforming methods. Unsteady, Reynolds-averaged Navier-Stokes equations with one equation Spalart-Allmaras and two-equation SST $k-\omega$ turbulence models are solved for unsteady flow problems. A fully implicit time marching scheme based on the Newmark direct integration method is used flow computing the coupled governing equations of the fluid-structure interaction problem. Detailed FIV responses for different flow conditions are presented with respect to time and vibration characteristics are also physically investigated in the time domain.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.496-500
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• 2004

A new, commercially available polishing process called magnetorheological finishing is used to polish and figure precision optics. To understand and model this process correctly it is important to determine the mechanical properties of the fluid under the influence of the magnetic field. Magnetorheological (MR) fluids are commonly modeled as Bingham fluids, so one of the essential properties to measure is the yield stress. Since MR fluids are inherently anisotropic, the yield stress will depend on the mutual orientation of the magnetic field and the direction of deformation. The relative orientation of the field and deformation in polishing does not coincide with common rheological setups, so a new rheometer has been designed and tested. This new magnetorheometer design has been shown to give correct stresses during calibration experiments using Newtonian fluids with a known viscosity. The measured stress has also been shown to have a magnitude consistent with published finite element approximations for magnetic fluids. The design of the instrument was complicated because of the requirements imposed upon the magnetic field, and the difficulty in satisfying the no slip boundary condition. Our results show the importance of having a homogeneous field in the test region during measurements. The solutions to these problems and discussion of the measurements on nonmagnetic and magnetic fluids are given.

• 한국응용과학기술학회지
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• 제26권4호
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• pp.428-433
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• 2009

Cellulose triacetate (CTA) was prepared from cotton linter and pulps which contain various contents of $\alpha$-cellulose. CTA which contains 2.8 of degree of substitution (DS) and 222 of degree of polymerization (DP) was obtained from V-81 pulp under the heterogeneous system. The DS was measured by the titration method, and the DP was obtained by measurement of viscosity. FT-IR spectometer (FT-IR 6300, JASCO) was used to analyze the chemical structure of raw materials and cellulose triacetate, and X-ray diffractometer (X-pert MPD PW3040, Philips) was used to confirm the crystal structure and to calculate the relative crystallinity index (RCI). As $\alpha$-cellulose content in pulp increased, the acetylation yield increased. Besides with a kind of pulp, it contains insoluble residue which was mainly formed due to the formation of glucomannan triacetate and xylan diacetate during the esterification.

• Journal of Ginseng Research
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• 제24권1호
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• pp.41-45
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• 2000

인삼전분으로부터 기능성 말토올리고당을 생산하기 위하여 인삼전분에 대한 말토 올리고당 생산 최적조건을 검토하고 이들을 정제 한 후 물리화학적 특성과 장내 유용 세균에 대한 생육효과를 조사하였다. Amano-A amylase를 사용하였을 때 glucose가 4개 이상 결합된 말토 올리고당이 많이 생성되어 최적 효소로 선정하였고, 이 효소를 이용한 말토 올리고당 생산 최적조건은 인삼전분 10%, 효소 첨가 농도 50 unit/g 전분 과 반응시간 24시간이었다. 인삼전분을 효소분해하여 생산하고 carbon-celite로 정제한 말토올리고당의 점도와 보수력은 각각 37.7 cps(20。C)와 110%(75%상대습도)로 설탕에 비하여 높았으며, 감미도는 설탕의 25.6% 이었다. 또한 생산된 말토올리고당은 장내 유용세균인 Biflidobacterium infantis의 생육을 촉진시켰다