• Archives of Pharmacal Research
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• 제23권1호
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• pp.72-78
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• 2000

The general pharmacological properties of YJA20379-1 2-dimethylamino-4,5-dihydrothiazolo[4,5:3,4]pyridol[1,2-a]benzoimidazole, a novel proton pump inhibitor with antiulcer activities were investigated in mice, rats, guinea pigs and rabbits. YJA20379-2 at oral doses of 50, 100 and 200 mg/kg did not affect the general behaviour, hexobarbital hypnosis and motor coordination in mice. The drug did not have analgesic or anticonvulsant action at 200 mg/kg. Locomotor activity and body temperature were not influenced at 100 mg/kg. At a concentration up to 2{\times}10^{-4} g/ml$, YJA20379-2 did not produce any contraction or relaxation of isolated preparations, such as the rat fundus, the guinea pig ileum and the rat uterus, and did not antagonize the contractile response to several spasmogens, such as histamine, acetylcholine, serotonin and oxytocin. At dosages up to 200 mg/kg p.o. YJA20379-2 did not affect the pupil size of mice. Intestinal propulsion of mice was not affected up to 200 mg/kg p.o. and the drug did not affect urinary excretion at 100 mg/kg p.o. These results indicate that at dosages up to 100 gm/kg p.o. YJA20379-2 was found not to affect this pharmacological profile. However, at 200 mg/kg the drug lowered body temperature and showed decreased in locomotor activity and urine volume.

• 폴리머
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• 제34권3호
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• pp.220-225
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• 2010

폴리에테르설폰(PES) 필름의 주사슬 연신에 의한 광학 특성 변화와 보상 필름으로 사용 환경온도에 따른 이들의 특성변화를 살펴보았다. 아울러 연신 및 열처리가 필름의 광학 특성 및 치수안정성에 미치는 영향을 함께 확인하였다. PES는 연신에 의하여 광학용 보상 필름으로 사용이 가능할 정도의 $R_e$ 값과 $R_{th}$ 값을 얻을 수 있었으며 이러한 값들은 반복적인 사용 환경 온도에 따라 변화되며 이를 최소화하기 위하여 열처리 공정이 필요함을 알 수 있었다. 연신된 PES 필름은 사용온도가 증가됨에 따라 연신에 의한 주사슬의 수축이 발생되며 그 이후 고유 특성인 열팽창이 일어나며, 연신에 의한 주사슬 배향에 의하여 열팽창계수는 다소 감소함을 알 수 있었다. 필름의 열처리는 열팽창계수에는 크게 영향을 미치지 않는 반면 열수축을 현저하게 감소시킴을 확인하였다.

• 한국안광학회지
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• 제5권1호
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• pp.49-53
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• 2000

Sodium borate silicate 유리는 $10Na_2O-39B_2O_3-50SiO_2-CoO$ mol%와 $20Na_2O-14B_2O_3-65SiO_2-CoO$ mol%의 조성비로 혼합한 후 전기로에서 $1210^{\circ}C$ 온도로 2시간 동안 용융하여 공기 중에서 급냉 시켜 제작하였다. 급냉한 유리의 유전적 거동을 조사하기 위하여 온도와 주파수 함수로 유전상수와 비저항을 측정하였다. 유전율 스펙트럼에서 유리전이온도는 $Na_2O$ 20 mol%시료가 낮아졌으며 $Na_2O$ 함량이 증가함에 따라 유전상수는 크게 나타났다. 유리의 비저항 주파수 의존성은 non-Debye형 완화를 보였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.237-238
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• 2006

The electrical properties such as dielectric constants and dielectric losses in the spinel samples of $LiGaTiO_4$, Li(Ga,Eu)$TiO_4$, $Li(Ga.Yb)TiO_4$ have been characterized by varying measuring temperature and frequency. The long range order structures are analyzed by rietveld refinement method. and local atomic disorder structures are analyzed by MEM (maximum entropy method). The relation between the crystal structure and dielectric properties are discussed. $LiGaTiO_4$ spinel has the IMMA with lattice constant, a = 5.86333, b=17.5872. c = 8.28375 ${\AA}$, Li-sites are partially substituted by Ga or Ti. Two crystallographic oxygen sites are partially occupied(40~50%). The dielectric constants of $LiGaTiO_4$, $LiYbTiO_4$, and $LiGa_{2/6}Eu_{1/6}Ti_{1.5}O_4$ ceramics were 127, 75 and 272, respectively at 100 kHz. The dielectric relaxation were observed in the $LiGaTiO_3$ ceramics and the temperature where dielectric loss shows maximum was $390^{\circ}C$ at 1 kHz and increased with increasing the measuring frequency.

• 폴리머
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• 제27권2호
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• pp.113-119
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• 2003

폴리(에틸렌 테레프탈레이트) (PET)의 열처리 조건들 즉, 상대 습도, 온도 그리고 시간 등에 따라 나타나는 PET의 열적 특성과 결정화 거동에 대해서 연구하였다. PET샘플에 열처리를 수행한 후 수분 함유량, 유리 전이온도($T_g$), 그리고 결정화 온도($T_{\propto}$) 등의 변화를 조사하였다. 그리고 열처리된 PET시편에 대해서 결정화를 시키고 결정화도에 따른 열변형 온도(HDT)를 측정하였다. 또한 사출 성형으로 제작된 PET샘플의 열처리 후 잔류 응력의 완화를 편광 필름을 통하여 조사하였다. 열처리 시의 상대 습도, 온도, 그리고 시간이 증가함에 따라 PET샘플 내의 수분 함유량은 최대 6000 ppm이상 까지 증가하였다. $T_g$와 $T_c$는 시편 내에 수분 함유량이 증가할수록 감소하였다. PET샘플의 결정화도는 수분의 함유량이 증가함에 따라 증가되었다. 그러나 같은 양의 수분 함량에서 결정화도는 열처리의 조건에 따라 다르게 나타났다. PET샘플 내의 잔류응력의 완화는 열처리 조건에 따라 다르게 나타났으며, PET샘플 내에 잔류 응력이 감소할수록 최대 결정화도는 증가하였다.

• 한국수소및신에너지학회논문집
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• 제26권2호
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• pp.120-126
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• 2015

Recently, the ever-increasing use of fossil fuels for rapid industrial development and population significantly caused an environment pollution and global warming such as climate change. So research and development of sustainable and eco-friendly energy have been performed. Especially the interest in nuclear fusion fuel was significantly increased from the developed countries. The system of fusion energy production was tritium separation, storage and delivery, and purification. Republic of Korea is in charge of Storage and Delivery System (SDS) in the International Thermonuclear Experimental Reactor (ITER). Welding part of the SDS bottles for storing the tritium is known to be susceptible to hydrogen embrittlement. In this study, conducted a study for the relaxation of the stability and hydrogen embrittlement of the weld area. The hydrogen heat treatment was processed through the Pressure-Composition-Temperature (PCT) device according to the time variation. Also mechanical properties such as impact test and hardness test according to using the alkaline cleaning liquid for hydrogen embrittlement relief and the fracture was observed by scanning electron microscopy (SEM) after the mechanical properties evaluation.

• 한국재료학회지
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• 제30권10호
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• pp.495-501
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• 2020

The various sintered samples comprising of 72 wt% (Al₂O₃) : 28 wt% (SiO₂) based ceramics were fabricated using a colloidal processing route. The phase analysis of the ceramics was performed using an X-ray diffractometer (XRD) at room temperature confirming the presence of Al₂O₅Si and Al_5.33Si_0.67O_9.33. The surface morphology of the fracture surface of the different sintered samples having different sizes of grain distribution. The resistive and capacitive properties of the three different sintered samples at frequency sweep (1 kHz to 1 MHz). The contribution of grain and the non-Debye relaxation process is seen for various sintered samples in the Nyquist plot. The ferroelectric loop of the various sintered sample shows a slim shape giving rise to low remnant polarization. The excitation performance of the sample at a constant electric signal has been examined utilizing a designed electrical circuit. The above result suggests that the prepared lead-free ceramic can act as a base for designing of dielectric capacitors or resonators.

• 한국재료학회지
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• 제18권5호
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• pp.235-240
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• 2008

This paper presents results and observations obtained from a study of the optical and thermal properties of alkali tellurite depending on the composition. Fourier transform infrared (FT-IR) spectra showed evidence of chemical modification from $TeO_4$ trigonal bipyramids (tbp) to $TeO_3$ trigonal pyramids (tp) in tellurite glasses. The optical band gaps of the different glass samples calculated using Tauc's method were found to range from 3.5-3.8 eV. The glass transition temperature (Tg) and glass stability (${\Delta}T$) of alkali tellurite glasses were investigated, as $M_2O$ [M: Li, Na, K] amounted to 25 mol%, through the use of differential thermal analysis (DTA). The coefficient of thermal expansion (CTE) was measured in a thermo mechanical analysis (TMA) with a slow heating rate after the glass samples were annealed. The results confirm that the optical band gap of alkali tellurite glasses depends on the Te-O-Te structural relaxation related to the ratio of bridging/non bridging oxygen (BO/NBO). In contrast, the thermal properties are related to the ionic field strength of the Te-O-M and M-O-M bonds, and the Te-O-Te breakage depends on the ratio of BO/NBO.

• 한국자기학회지
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• 제3권4호
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• pp.298-304
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• 1993

Pd/Co 다층박막을 동시열증착장치로 제작하여, 토오크 자력계, 홀 효과 측정장치 및 X-선 회절기를 이용하여 기판 온도, Pd하지층에 따른 구조적 자기적 및 열적 특성변화를 연구하였다. 기판 온도가 증가함에 따라 $150^{\circ}C$까지는 계면구조 및 각 층의 결정성이 향상되고, (111) 집합조직이 발달되었으며 따라서 계면자기이방성 및 수직자기 이방성에너지는 증가하였다. 그러나 보자력은 감소 하였는데 이는 입자의 성장으로 인한 자구벽 고착효과 감소에 기인된 것으로 보이며 Pd하지층이 두꺼 울 수록 다층박막의 입자크기는 컸다. $200^{\circ}C$ 이상에서는 계면에서 상호확산에 의하여 다층막의 구조의 열화는 촉진되었다. 열처리 초기에 주 피이크 강도의 변화는 컸으며 그 후부터는 작은 폭으로 감소하였다. 초기의 큰 강도 변화는 구조이완등의 현상에 기인된 것으로 추측되며 그 후는 확산에 의 해서이다. 다층박막의 상호확산에 필요한 활성화 에너지는 14.9 KCal/mole.K 였다.

• Tribology and Lubricants
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• 제35권1호
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• pp.52-58
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• 2019

In the case of high-voltage connectors applied to automobiles, waterproofing has become an important issue for the safety of automobiles. In this study, structural analysis is performed on silicone rubber-type waterproof seals used in the voltage connector. For the structural analysis, the tensile properties of the actual rubber seal are evaluated using a miniaturized tensile testing machine. The Mooney-Rivlin material constants of the rubber seal are determined as follows; $D_1=0$, $C_{01}=0.241$, $C_{10}=0.0142$. The analysis shows that the contact pressure at the top of the seal where the seal and male connector are in contact is approximately three times higher than that at the bottom of the seal where the seal and female connector are in contact. It is confirmed that the waterproofing performance of the rubber seal depends on the contact pressure of the seal bottom where the seal and female connector are in contact. The contact pressure for waterproofing is found to be 4.7 bar. The strain concentration of the curved part is attributed to excessive initial tension. Therefore, a redesign is recommended for uniform stress or strain distribution in the curved section of the seal in response to the stress relaxation problem due to permanent deformation.