• 한국수산과학회지
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• 제29권6호
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• pp.843-848
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• 1996

As the first step of studies related to production of chitooligosaccharides by physical methods, chitosan solution were sonicated with 20 kHz and various treatment effects were examined to present fundamental data of sonicated chitosan solution. Intrinsic viscosity of chitosan solution sharply decreased from 3.76 dl/g to 2.90 dl/g until 5 minutes of sonication and then slowly decreased. With low volume of chitosan solution, sonication was very effective and temperature of chitosan solution slightly affected the efficiency of sonication. In case of changing the solvent, no significant differences were observed on the effect of sonication, however, acetate buffer had highest sonication effect among various solvents. The sonication effect was increased as the increasement of the value of pH, on the contrary, ionic strength and type of counterions showed no effect on sonication. With these results, we assumed that optimal sonication treatment would be as follows, solution volume was $10\~20\;ml$, temperature range was $20\~30^{\circ}C$, pH value of solution was 4.5 and type of solvent was acetate buffer.

• Applied Biological Chemistry
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• 제35권1호
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• pp.10-13
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• 1992

쌀보리 3품종의 전분을 큰 입자$(17{\sim}34$ 미크론)와 작은 입자$(4{\sim}20$ 미크론)로 분리하고 이들의 성질을 비교하였다. 작은 입자의 수는 새쌀보리가 62%, 늘쌀보리와 무등쌀보리는 75%였다. 전분의 일반성분과 물결합 능력은 큰 입자가 가장 낮았고, 청색도 값은 작은 입자가 낮은 값을 보였다. 팽윤력과 용해도는 입자별로 큰 차이가 없었고, 고유점도는 큰 입자가 작은 입자 보다 높았다. X-선 회절도는 큰 입자와 작은 입자 사이에 차이가 없었다. 알칼리에 의한 점도는 큰 입자가 높았고 복굴절성의 소실에 의한 호화 온도는 차이를 보이지 않았다.

• 한국식품과학회지
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• 제25권3호
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• pp.264-269
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• 1993

아밀로오스와 아밀로펙틴의 고유점도와 중합도는 강남콩이 다른 시료에 비해 작았다. 겔 크로마토그래피에 의한 분자량 분포의 연구에서는 전분의 경우 강남콩이 대체로 작은 분자들이 많음을 보여주었다. 아밀로오스의 분자량 분포는 특히 강남콩 아밀로오스가 분자량이 작은 것으로 나타났으며 동부와 녹두는 강남콩이나 팥보다 컸고, 팥은 중간이었다. 아울러 아밀로펙틴의 경우 pullulanase로 분해시켰을 때 잘라지는 가지 부분들이 강남콩은 약간 짧았고 동부나 녹두는 강남콩보다는 길었으며 서로 비슷했다. 또한 동부나 녹두는 긴 사슬(DP 40 부근)에 비해 짧은 사슬(DP 15 부근)의 비율이 더 크게 나타났다.

• 한국응용과학기술학회지
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• 제6권1호
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• pp.1-7
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• 1989

To developed new process for obtaining maximum molecular weight of anionic acrylamide and acrylic acid copolymer by inverse emulsion polymerization. Concentration of initiator, reducing agent, surfactant and mole ratio of acrylamide-acrylic acid were studied for the process. Semi-batch processes with method of redox, control of reaction temperature, feeding method of monomer and reaction time, was suitable for maximum molecular weight of P(AMAC) from this process obtained $3.09\;{\time}\;10^6({\bar{M}}n.)$ and $4.41\;{\time}\;10^6({\bar{M}}w.)$ in molecular weight measured by the intrinsic viscosity method. inverse emulsion polymerization mechanism of P(AMAC) does not followed the Smith-Ewart and Medvedev theory, but selected for concentration of initiator, reducing agent, surfactant, water solubility of monomer.

• 한국식품저장유통학회지
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• 제5권4호
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• pp.368-373
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• 1998

도토리 묵 제조의 최적조건을 찾기 위한 기초자료를 얻기 위하여 수침과 수세정도를 달리하여 제조한 도토리 묵가루의 일반성분 및 이화학적 특성을 조사하였다. 수침과 수세의 정도가 증가할수록 조단백질, 회분, 총페놀은 감소하였으며, 조지방과 식이섬유소는 변화가 거의 없었다. 색도 또한 L값은 증가하였고, a값과 b값은 감소하는 경향을 보였다. 팽윤력은 수침과 수세정도가 증가할수록 증가하였으며, 용해도는 처리정도에 따라 감소하였으나 변화양상이 일정하지는 않았다. 물결합능력은 대조구에서 높았으며 처리정도에 따라 감소하였다. 고유점도 또한 처리정도에 따라 증가하였다. 이러한 결과들은 수침보다는 수세에 의한 영향이 더 컸다.

• Macromolecular Research
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• 제12권3호
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• pp.303-310
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• 2004

We have prepared an aqueous dispersion of poly(aniline-dodecyl benzene sulfonic acid complex) (PANI-DC) that has an intrinsic viscosity (〔η〕) near 1.3 dL/g using aniline as a monomer, dodecyl benzene sulfonic acid(DBSA) as a dopant/emulsifier, and ammonium peroxodisulfate(APS) as an oxidant. We found that the electrical conductivity of a PANI-DC pellet was 0.7 S/cm. A waterborne-polyurethane (WBPU) dispersion, obtained from isophorone diisocyanate/polytetramethylene oxide glycol/dimethylol propionic acid/ethylene diamine/triethylene amine, was used as a matrix polymer. We prepared blend films of WBPU/PANI-DC with variable weight ratios (from 99/1 to 66/34) by solution blending/casting and investigated the effects that the PANI-DC content has on the mechanical and dynamic mechanical properties, hardness, electrical conductivity, and antistaticity of these films. The tensile strength, percentage of elongation, and hardness of WBPU/PANI-DC blend films all decreased markedly upon increasing the PANI-DC content. The antistatic half-life time ($\tau$$\sub$$\frac{1}{2}$/) of pure WBPU film was about 110 s, but we found that those of WBPU/ultrasound-treated PANI-DC blend films decreased exponentially from 1.2 s to 0.1 s to almost 0 s upon increasing the PANI-DC content from 1 wt% to 15 wt% to > 15 wt%, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.284-287
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• 2001

Multi-pole anisotropic Sr-fertile sintered magnets has been studied by powder injection molding under applied magnetic field. The orientation of anisotropic Sr-ferrite powders higher than 80% during injection molding is achieved at the following conditions; apparent viscosity lower then 2500 poise in 1000 sec$\^$-1/ shear rate and applied magnetic field higher then 4 kOe. For the high fluidity and strength of injection molded compact, and the effective binder removal without defects during solvent extraction and thermal debinding, the optimum multi-binder composition is paraffin wax(PW)/carnauba wax(CW)/HDPE = 50/25/25 wt%. The rate of binder removal is proportional to the mean particle size of Sr-ferrite powders whereas it is inversely proportional to the content of Sr-ferrite powders and the sample thickness. The high magnetic properties of Sr-ferrite sintered magnets are; 3.8 kG of remanent flux density, 3.4 kOe of intrinsic coercivity, and 1.2 kG of surface flux density (1-mm-thick) in the direction of applied magnetic field.

• Applied Biological Chemistry
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• 제35권5호
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• pp.389-394
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• 1992

건열$(130{\sim}220^{\circ}C)$ 처리가 옥수수 전분의 성질에 미치는 영향을 조사하였다. 표면 색도의 경우 L값과 a값은 큰 차이가 없었으나 b값은 열처리에 따라 약간 감소하였다. Blue value는 $190^{\circ}C$ 이상에서 약간 증가하였고 물결합능력은 열처리 온도의 상승에 따라 증가하였다. 팽윤력은 시료간에 큰 차이가 없으나 $90^{\circ}C$에서의 팽윤력은 $190^{\circ}C$ 이상의 시료에서 약간 감소하였고 용해도는 $190^{\circ}C$ 이상에서 증가하였다. $190^{\circ}C$ 이상에서 고유점도의 상당한 감소, 전분결정도의 감소, 산 또는 효소에 의한 가수분해율의 뚜렷한 증가경향을 나타내었다.

• International Journal of Reliability and Applications
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• 제17권2호
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• pp.137-147
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• 2016

The engine mount of a car subjected to a pre-load related to the weight of the engine, and acts to insulate the vibration coming from the engine by moving on large or small displacement depending on the driving condition of the car. The vibration insulation of the engine mount is an effect obtained by dissipating the mechanical energy into heat by the viscosity characteristic of the rubber and the microscopic behavior of the additive carbon black. Therefore, dynamic stiffness from the intrinsic properties of rubber filled with carbon black at the design stage is an important design consideration. In this paper, we introduced a hyper-elastic, visco-elastic and elasto-plastic model to predict the dynamic characteristics of rubber, and developed a fitting program to determine the material model parameters using MATLAB. The dynamic characteristics analysis of the rubber insulator of the ACTIVE MOUNT was carried out by using MSC.MARC nonlinear structural analysis software, which provides the dynamic characteristics material model. The analysis results were compared with the dynamic characteristics test results of the rubber insulator, which is one of the active mount components, and the analysis results were confirmed to be valid.

• 한국자기학회지
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• 제5권5호
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• pp.740-744
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• 1995

For the fabrication of a multi-pole anisotropic Sr-ferrite magnet by powder injection molding, it is important to control effectively the alignment of magnetic powders during the injection molding process. The effect of the fluidity of powder/binder mixture on the powder alignment was studied with changing the particle sizes and the volume fraction of Sr-ferrite magnetic powders. The critical volume fraction of Sr-ferrite powders increases from 58 vol.% to 64 vol.% as the mean powder size increases from $0.8\;\mu\textrm{m}$ to $1.2\;\mu\textrm{m}$. A Sr-ferrite powder alignment greater than 80 % is achieved at the conditions of an apparent viscosity lower than 1000 poise at $1600\;sec^{-1}$ shear rate, an applied magnetic field higher than 4 kOe, and a powder volume fraction 8 vol.% lower than the critical fraction. The powder alignment obtained during the injection molding process is not much affected by the subsequent processes of debinding and sintering, showing the magnetic properties of 3.8 kG of remanent flux density and 3.37 kOe of intrinsic coercivity.