• Preventive Nutrition and Food Science
• /
• 제20권2호
• /
• pp.119-125
• /
• 2015

The biologically active compounds raphasatin and sulforaphene are formed during the hydrolysis of radishes by an endogenous myrosinase. Raphasatin is very unstable, and it is generated and simultaneously degraded to less active compounds during hydrolysis in aqueous media. This study determined the hydrolysis conditions to maximize the formation of raphasatin and sulforaphene by an endogenous myrosinase and minimize their degradation during the hydrolysis of radish roots. The reaction parameters, such as the reaction medium, reaction time, type of mixing, and reaction temperature were optimized. A stability test for raphasatin and sulforaphene was also performed during storage of the hydrolyzed products at $25^{\circ}C$ for 10 days. The formation and breakdown of raphasatin and sulforaphene in radish roots by endogenous enzymolysis was strongly influenced by the reaction medium, reaction time, and type of mixing. The production and stabilization of raphasatin in radishes was efficient in water and dichloromethane with shaking for 15 min at $25^{\circ}C$. For sulforaphene, the favorable condition was water as the reaction medium without shaking for 10 min at $25^{\circ}C$. The maximum yields of raphasatin and sulforaphene were achieved in a concurrent hydrolysis reaction without shaking in water for 10 min and then with shaking in dichloromethane for 15 min at $25^{\circ}C$. Under these conditions, the yields of raphasatin and sulforaphene were maximized at 12.89 and $1.93{\mu}mol/g$ of dry radish, respectively. The stabilities of raphasatin and sulforaphene in the hydrolyzed products were 56.4% and 86.5% after 10 days of storage in water and dichloromethane at $25^{\circ}C$.

• 한국재료학회지
• /
• 제20권2호
• /
• pp.82-89
• /
• 2010

Benzotriazole (B.T.A) which has been mainly used for the stabilization processing method of excavated copper and bronze artifacts is vaporized within 2~3 years after the usage because it is unstable at the acid conditions and cannot protect the surface of artifacts. In this study, NaOH method which has been used for the steel artifacts was applied as a stabilization process for the method of copper and bronze artifacts to gush chlorine ion out. For the reproduction of excavated samples, copper and bronze plates were dipped in 0.1M HCl for 26 hrs to form CuCl, rusted at $70^{\circ}C$ with RH 75% for the formation of corrosion products, and desalted in 0.1 M NaOH solution. The concentration of chlorine ion was measured by using ionchromatography. During the desalting process, a large quantity of chlorine ions was gushed out in early period and corrosion products were not additionally generated through the re-corrosion experiment. This NaOH desalting process was found to be a method of stabilization process for copper and bronze artifacts from the formation of Tenorite (CuO) during desalting as a protection layer for corrosion.

• 한국응용과학기술학회지
• /
• 제18권2호
• /
• pp.118-126
• /
• 2001

Micelle formation and adsorption at the $Ti0_{2}$ interface of a series of polystyrene-polythylene oxide(PS-PEO) block copolymer in aqueous solution was studied using fluorescence probing and small-angle X-ray methods. Further, the stability of aqueous $Ti0_{2}$ dispersion in the presence of copolymer was investigated by microelectrophoresis, optical density and sedimentation measurements. The dissolution of pyrene as fluorescent probe in aqueous surfactant solution leads to a slow decrease of the $I_{1}/I_{3}$ ratio, as the copolymer concentration increase; $I_{1}$ and $I_{3}$ are respectively the intensities of the first and third vibrionic peaks in the pyrene fluorescence emission. The behaviour was due to the characteristics of the copolymers and/or to the copolymer association efficiency in water. Moreover, the adsorption at the plateau level increases with decreasing PEO until chain length. The zeta potential of $TiO_{2}$ particles decreases with increasing copolymer concentration and reaches a plateau value. Finally, stabilization using block copolymers was more effective with samples having higher weight fractions of PS block.

• Elastomers and Composites
• /
• 제22권2호
• /
• pp.109-120
• /
• 1987

In this study, as one of the developing ways of the functional elastomer, improvement of the functionality of CB-BR was attemped through stabilization. At first the stabilization effect of CB-BR and the concentration dependancy in CB-BR were determined. Then, triazine thiol derivative(BPTT) was synthesized by reacting p-aminodiphenylamine with cyanuric chloride. Further the functional mechanism and the effects of the antioxidants were investigated using BPTT together with other various antioxidants in liquid and solid states. The results obtained are as follows: 1) The aging of CB-BR depended on the concentration and temperature. Thus, at a low temperature of $50^{\circ}C$, the aging proceeded with gel formation; at high temperature above $100^{\circ}C$ and in above 4wt% concentration, the aging occured by the formation of gel. And in concentrations below that, the aging proceeds with a decomposition caused by oxygen attacked to elastomer molecules. 2) The effect of antioxidation of CB-BR in the liquid state was at it's best when the MBIZ and BPTT were used at $110^{\circ}C$, 4hrs after the oxidation. 3) The effect of antioxidation of CB-BR in the solid state was the best choice the simultaneous use of NDBC and BPTT at $50^{\circ}C$, 30days after the oxidation.

• 한국축산식품학회:학술대회논문집
• /
• 한국축산식품학회 2002년도 정기총회 및 제29차 춘계국제 학술발표대회
• /
• pp.82-89
• /
• 2002

Acid dairy drinks(ADD) are a worldwide product existing in many variations: fruit milk drinks, yogurt drinks, soy milk, butter milk, whey drinks and kefir etc. These drinks are marketed with different shelf lives depending on processing: -Short shelf life(maximum 3 weeks, cold storage) - Long shelf life(2 to 9 months, pasteurized, sterilized or retorted) Acidic protein drinks tend to a separation or destabilization process in the absence of stabilizing system during the shelf life of the ADD. A phase separation results in sedimentation of large particles at the bottom of the package and/or the formation of a serum layer at the top(whey off). These beverages are usually composed of an acid dairy phase (fermented base)or a natural base(milk, soymilk etc.)with an acidic medium (fruit phase: pulp, fruit concentrate etc.) which can be flavored. Sugar and stabilizers are added. It has been proved since the late 1950's that adding high methoxy pectin (HM pectin)to acid milk drinks is the best way to prevent the formation of a sediment and/or the whey off. In this presentation, we explain about stabilization mechanism of ADD induced by pectin. Applications and market trend of ADD in Asia and Europe are explained.

• 한국항공우주학회지
• /
• 제48권11호
• /
• pp.889-902
• /
• 2020

본 연구에서는 직접 연결식 초음속 연소기에서 설계점을 만족하는 초음속 유동의 형성유무 및 안정화 소요시간을 확인하기 위한 수치해석이 수행되었다. 이를 위하여 연소식 공기 가열기 하류의 고압 유동이 초음속 연소기로 전파되며 초음속 유동장을 형성해가는 과정을 살펴보았다. 압력 및 온도 분석을 통해, 초음속 유동장이 설계점인 마하수 2.0, 1,000 K을 만족하며, 최소 4.0 ms의 안정화 시간이 필요함을 확인하였다. 따라서 초음속 연소시험에서 연료분사 이전에 유동 안정화에 필요한 시간을 고려해야 함을 알 수 있었다.

• 한국공간구조학회논문집
• /
• 제3권4호
• /
• pp.77-84
• /
• 2003

Tensegrity systems are stable structures which are reticulated spatial structures composed of compressive straight members, struts and cables. But there are some difficulties concerning surface stability, surface formation and construction method. One of the ways to solve this problem reasonably is combination of tesile members and rigid members. This structure is a type of flexible strutural system which is unstable initially because the cable material has little initial rigidity. Therefore tensegrity structure need to be introduced to the Initial stress for the self-equilibrated system having stable state. The rigidification of tensegrity systems is related to selfstress states which can be achieved only when geometrical and mechanical requirements are simultaneously satisfied. In this paper, for the stabilization of tesnsegrity structure it is proposed the modified self-equilibrated equation and the range of the various geometrical parameter about unit system. And we generate the model of double layed single curvature arch using the new squew quadruplex unit system.

• 제어로봇시스템학회논문지
• /
• 제19권5호
• /
• pp.398-409
• /
• 2013

This paper provides an overview of distance-based formation control. Firstly, in this paper, we introduce preliminary background materials that are used in defining the distance-based formation control. Then, based on the preliminary background, we briefly review main results developed thus far in this field. Lastly, we provide some issues that need to be studied further in future works.

• Geomechanics and Engineering
• /
• 제28권3호
• /
• pp.255-263
• /
• 2022

Lime stabilization has conventionally been listed amid the key techniques of chemical stabilization. Replacing lime with sustainable agro-based by-products have gained prominence in recent decades. Bagasse ash (BA) is one such potential alternatives, an industrial waste with abundance in production, and industries exploring sustainable solutions for its safe disposal. Supplementing BA with lime could be an ideal approach to reduce lime consumption. However, suitability of BA and lime for the stabilization of expansive clays, such as black cotton (BC) soil is yet to be explored. This paper therefore aims to investigate the suitability of BA-lime mixtures to stabilize BC soil with emphasis to compaction behaviors and unconfined compressive strength (UCS) using standard laboratory procedures. Suitability of BA-lime mixture is then assessed against addition of calcium sulphate which, from previous experience, is detrimental with lime stabilization. Experimental outcomes nominate 15% BA as the optimum value observed from both compaction and UCS data, while addition of 4% lime to 15% BA showed the best results. Mineralogical and microstructural analysis show the presence of cementitious compounds with addition of lime and calcium sulphate with curing periods. While, formation of Ettringite needles were noted with the addition of calcium sulphate in BA-lime mixtures (at optimum values) after 90-day curing, and UCS results showed a decrease at this point. To this end, addition of BA in lime stabilization showed encouraging results as assessed from the compaction and UCS results. Nonetheless usage of calcium salts, with utmost emphasis on calcium sulphate and equivalent should be avoided.

• 대한환경공학회지
• /
• 제22권6호
• /
• pp.1055-1061
• /
• 2000

희분식 반응기에서 폐윤활유를 열분해하였을 때 생성된 오일의 타르생성에 관한 속도연구와 오일의 안정화 연구를 수행하였다. 열분해유에서 타르가 생성되는 과정은 직렬반응과 병렬반응이 결합된 lumped kinetic 모델을 제시하여 실험결과와 비교하였다. 제시된 모델로부터 타르를 생성하는 반응속도 결정단계는 열분해 생성유가 중간반응 단계를 거치지 않고 바로 타르가 되는 경로임을 알 수 있었다. 오일의 안정화를 위해 fly ash와 coke를 첨가하였을 때 타르를 생성하는 물질의 제거 및 산화방지 효과가 큰 것을 확인할 수 있었다.