• 전기학회논문지
• /
• 제66권5호
• /
• pp.800-805
• /
• 2017

The accelerated thermal ageing of CSPE (chlorosulfonated polyethylene) was carried out for 16.82, 50.45, and 84.09 days at $110^{\circ}C$, equivalent to 20, 60, and 100 years of ageing at $50^{\circ}C$ in nuclear power plants, respectively. As the accelerated thermally aged years increase, the insulation resistance and resistivity of the CSPE decrease, and the capacitance, relative permittivity and dissipation factor of those increase at the measured frequency, respectively. As the accelerated thermally aged years and the measured frequency increase, the phase degree of response voltage vs excitation voltage of the CSPE increase but the phase degree of response current vs excitation voltage decrease, respectively. As the accelerated thermally aged years increase, the apparent density, glass transition temperature and the melting temperature of the CSPE increase but the percent elongation and % crystallinity decrease, respectively. The differential temperatures of those are $0.013-0.037^{\circ}C$ and, $0.034-0.061^{\circ}C$ after the AC and DC voltages are applied to CSPE-0y and CSPE-20y, respectively; the differential temperatures of those are $0.011-0.038^{\circ}C$ and $0.002-0.028^{\circ}C$ after the AC and DC voltages are applied to CSPE-60y and CSPE-100y, respectively. The variations in temperature for the AC voltage are higher than those for the DC voltage when an AC voltage is applied to CSPE. It is found that the dielectric loss owing to the dissipation factor($tan{\delta}$) is related to the electric dipole conduction current. It is ascertained that the ionic (electron or hole) leakage current is increased by the partial separation of the branch chain of CSPE polymer as a result of thermal stress due to accelerated thermal ageing.

• 한국안광학회지
• /
• 제8권2호
• /
• pp.85-89
• /
• 2003

구면 RGP 렌즈는 렌즈 후면과 각막 사이에 눈물이 일정한 두께를 형성하면서 뛰어난 난시교정효과를 나타낸다. 이러한 RGP 렌즈의 난시교정 효과를 체계적으로 연구하여 임상 구면 RGP 렌즈처방에 활용하고자 렌즈착용 전후의 전체난시량 변화 각막난시량의 변화, 잔여난시 변화를 비교, 분석하여 다음과 같은 결론을 얻었다. 1. 구면 RGP 렌즈의 교정 전 후 전체난시량이 2.00D 이하에서는 교정이 거의 모두 이루어졌으나, 전체 난시량이 2.50D 이상에서 미교정된 상태를 보였으며, 특히 3.00D 이상에서는 난시 교정효과가 급격히 감소되는 것으로 나타났다. 2. 구면 RGP 렌즈의 교정 전 후 각막난시량은 2.50D 이하에서 약도의 저교정 상태로 나타났으나, 3.00D이상에서는 전체난시와 마찬가지로 난시 교정효과가 감소되는 것으로 나타났다. 3. 구면 RGP 렌즈 처방시 잔여난시량은 그대로 발현하는 것이 아니고, 잔여난시 도수가 일정부분 감소하여 전체난시 상태로 나타났다.

• 한국수산과학회지
• /
• 제40권1호
• /
• pp.1-7
• /
• 2007

The chemical and rheological properties of deproteinated porphyrans from laver Porphyra yezoensis were investigated to obtain basic data for the production of food materials with biological functionality. Deproteinated porphyran was prepared by acid extraction (pH 4.0, $80^{\circ}C$, 4 hr) and successive hydrolysis with 0.5% Alcalase and 0.5% Flavourzyme. The porphyran constituted 10.7% of the dry laver and consisted of 0.6% protein, 14.8% ester sulfate, 3.2% 6-O-methyl galactose, 16.0% 3,6-anhydro-L-galactose, and 67.3% galactose. The effects of concentration and temperature on the apparent viscosity were examined by applying the power law and Arrhenius equations. The porphyran solution showed the typical behavior of a pseudoplastic liquid and the flow behavior index decreased with increasing concentration. The activation energy of the deproteinated porphyran solution at a 1,000 L/s shear rate also increased from $1.4954{\times}10^{4}\;to\;1.9544{\times}10^{4}\;J/kg$ mol with the concentration.

• Journal of Korean Neurosurgical Society
• /
• 제43권6호
• /
• pp.294-299
• /
• 2008

Objective : To evaluate the clinical characteristics and surgical outcomes of the patients with cervical spondylotic myelopathy associated with athetoid cerebral palsy. Methods : The authors reviewed the clinical and neurodiagnostic findings, surgical managements and outcomes in six consecutive patients with cervical spondylotic myelopathy associated with athetoid cerebral palsy who had been treated with surgical decompression and fusion procedures between January 1999 and December 2005. The mean age of the 6 patients (four women and two men) at the time of surgery was 42.8 years (range, 31-55 years). The mean follow-up period was 56.5 months (range, 17-112 months). The neurological outcome was evaluated before and after operations (immediately, 6 months after and final follow-up) using grading systems of the walking ability, brachialgia and deltoid power. Results : At immediate postoperative period, after 6 months, and at final follow-up, all patients showed apparent clinical improvements in walking ability, upper extremity pain and deltoid muscle strength. Late neurological deterioration was not seen during follow-up periods. There were no serious complications related to surgery. Conclusion : Surgical decompression and stabilization in patients with cervical spondylotic myelopathy associated with athetoid cerebral palsy have been challenging procedure up to now. Our results indicate that early diagnosis and appropriate surgical procedure can effectively improve the clinical symptoms and neurological function in patients with cervical spondylotic myelopathy and athetoid cerebral palsy, even in those with severe involuntary movements.

• 한국식품영양과학회지
• /
• 제40권7호
• /
• pp.1048-1052
• /
• 2011

각기 다른 치환도를 가진 초산 고구마전분 페이스트의 유동특성 및 투과도 그리고, 이들 전분 겔의 냉.해동안정성 및 강도가 치환도의 함수로 분석되었다. 유동특성 측정 결과 power law 모델식과 Casson 모델식에 잘 적용되었으며, 높은 shear-thinning 거동을 가지고 있는 것으로 나타났다. 특정한 온도 범위($25{\sim}70^{\circ}C$)에서 전분 페이스트의 겉보기 점도($\eta_{a,100}$)의 온도 의존성은 Arrhenius 모델식에 잘 적용되었으며 초산 고구마전분이 천연전분에 비해 더 낮은 온도 의존성을 나타내었다. 전분 페이스트 이수현상 측정에서는 초산화에 의해 이수현상이 감소하는 것으로 나타났으며, 치환도가 증가할수록 낮아지는 것으로 나타났다. 겔 강도 측정에서도 초산화에 의해 겔 강도가 감소하는 것으로 나타났으며, 치환도가 증가할수록 겔 강도는 감소하는 것으로 나타났다. 페이스트 투과도(% T) 측정에서 초산전분은 천연전분 보다 투과도가 높은 것으로 나타났다.

• Preventive Nutrition and Food Science
• /
• 제18권1호
• /
• pp.45-49
• /
• 2013

This study was carried out to determine a possibility of adding Corni fructus extract (CFE) into yogurt for improving the neutraceutical properties of yogurt and the effects of adding CFE (2~6%, v/v) on the physicochemical and sensory properties of the products during a 15-day storage period at $4^{\circ}C$. Incorporation of CFE into the yogurt samples resulted in a significant pH reduction and a significant increase in titratable acidity. When evaluating the color of the yogurt, the $L^*$-values were not significantly influenced by CFE supplementation; however, the $a^*$- and $b^*$-values significantly increased with the addition of CFE during storage. The power law and Casson models were applied to assess the flow behavior of CFE-added yogurt samples. The magnitudes of apparent viscosity (${\eta}_{a,100}$), consistency index (K), and yield stress (${\sigma}_{oc}$) for 4~6% CFE yogurt samples were significantly greater than those for the control, indicating that CFE can be used as a thickening agent for yogurt. The sensory test revealed that addition of CFE (2~4%) to yogurt did not significantly affect the overall scores, but the overall preference score for 6% CFE yogurt was significantly decreased. Based on the data obtained from the present study, we concluded that the concentrations (2~4%) of CFE could be used to produce a CFE-added yogurt without the significantly adverse effects on the physicochemical and sensory properties.

• Food Science and Biotechnology
• /
• 제15권2호
• /
• pp.207-213
• /
• 2006

The effects of gellan gum (from S. paucimobilis), EPS-CB (exopolysaccharide from S. chungbukensis), and a series of commercial gums (arabic gum, xanthan gum, guar gum, deacyl gellan gum), on the swelling, rheological, and pasting properties of non-waxy rice flour dispersions were investigated. The swelling properties of rice flours in gellan or guar gum dispersion after heating were found to have increased with increasing gum concentrations, but the swelling properties of rice flour/other gum systems decreased with increasing concentrations. The rice flour/gum mixtures showed high shear-thinning flow behavior (n=0.14-0.32), and consistency index (K) was higher in guar gum than other gum dispersions. The initial pasting temperatures and peak times increased along with increasing gum concentration. The peak viscosity of rice flour increased in guar gum and deacyl gellan dispersions, and the breakdown and setback viscosity of the rice flour paste was lowest in the xanthan gum system, but remained higher than those of the control. The apparent viscosities of the rice flour/gellan gum mixture pastes were the highest among the tested combinations.

• 마이크로전자및패키징학회지
• /
• 제25권3호
• /
• pp.67-74
• /
• 2018

두께 $2.5{\sim}10{\mu}m$인 n형 $Bi_2Te_3$와 p형 $Sb_2Te_3$ 레그 8쌍으로 구성되어 있는 in-plane형 열전박막소자를 전기도금법으로 Si submounts에 형성하고, LED 칩의 구동에 의해 발생하는 겉보기 온도차 ${\Delta}T$와 레그 두께에 따른 발전특성을 분석하였다. LED 방출열에 의해 인가된 ${\Delta}T$가 7.4K일 때 각기 두께 $2.5{\mu}m$, $5{\mu}m$ 및 $10{\mu}m$의 p-n 레그들로 구성된 열전박막소자는 6.1 mV, 7.4 mV 및 11.8 mV의 open circuit 전압을 나타내었으며, 6.6 nW, 12.8 nW 및 41.9 nW의 최대 출력전력을 나타내었다.

• 지구물리와물리탐사
• /
• 제11권1호
• /
• pp.78-84
• /
• 2008

한국의 원자력발전소 부근에서 발생한 최근 지진으로 한반도 남동부에 위치한 울산단층대의 지진활동에 사회적 관심이 집중되고 있다. 이 단층대의 지하구조를 규명하기 위하여, 울산시 북쪽의 동천강 계곡에서 고분해능 탄성파 굴절법 및 반사법 탐사와 조밀한 간격의 중력탐사를 실시하였다. 이 지역에는 폭 약 1 km인 계곡 내의 충적층 하부에 단층대가 남북방향으로 놓여있다. 24채널 탄성파 굴절법 및 반사법 자료는 타격점과 수신점이 공히 5 m 간격으로, 길이 835 m와 415 m인 두 측선을 따라 기록하였다. 중력도 이 두 측선을 따라 10 m 간격으로 131점에서 측정하였다. 탄성파 굴절법 자료, 고분해능 반사법 자료, 중력 측정자료 등을 이용한 종합적 해석은 이 울산단층대가 백악기에 겉보기 남북방향의 주향이동 운동으로 형성되었고, 어떤 단층들은 신생대 3기 혹은 4기에 동서방향의 압축응력에 의하여 재활성되었을 가능성을 지시한다.

• 한국토양비료학회지
• /
• 제26권3호
• /
• pp.151-154
• /
• 1993

CEC가 67me/100g되는 천연(天然)zeolite 미분(微粉)을 3N-NaOH용액(溶液)에서 $80^{\circ}C$로 30시간(時間) 처리(處理)한 결과(結果), 반응생성물(反應生成物)의 CEC는 약 260me/100g으로 증가(增加)하였으며 서로 다른 반응조건(反應條件) 하(下)의 반응(反應) 생성물(生成物)중 가장 높았다. NaOH용액(溶液)을 처리(處理)하여 생성(生成)된 반응생성물(反應生成物)에는 천연(天然) zeolite에 함유(含有)되었던 clinoptilolite, mordenite 및 smectite의 함량(含量)은 감소(減少)하였으나 phillipsite로 새롭게 나타났다. 반응온도(反應溫度)와 반응시간(反應時間)이 증가(增加)할수록 phillipsite의 함량(含量)이 증가(增加)하였다. 30시간반응(時間反應) 후(後)에는 phillipsite가 주(主)된 점토광물(粘土鑛物)로 나타났다.