• 한국잠사곤충학회지
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• 제40권2호
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• pp.163-168
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• 1998

Hydrolysis rate and activation energy of Antheraea pernyi silk fiber treated with HCI were examined. Thermal decomposition temperature and surface morphology were also investigated by using differential scanning calorimeter and scanning electron microscope. As the concentration of hydrochloric acid and the treatment temperature increased, the hydrolysis occurred more rapidly. The activation energy of Antheraea pernyi, 74.0 kJ/mol, was higher than that of Bombyx mori, 58.1 kJ/mol. As the concentration of hydrochloric acid increases, the activation energy of Antheraea pernyi decreased from 74.0 kJ/mol to 62.0 kJ/mol. The shape of acid-resistance fraction of Antheraea pernyi became more distroyed and was transformed from fiber to powdered form with an increase of hydrolysis rate. The thermal decomposition temperature of Antheraea pernyi was 360.8$^{\circ}C$ until the hydrolysis rate was 81.8 wt%, but ti decreased to 347.0$^{\circ}C$ when the hydrolysis rate was 93.8 wt%.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 1999년도 춘계 학술발표회 논문집
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• pp.165-170
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• 1999

Palladium membranes have high selectivity of separation and removal of hydrogen to chemical process at high temperature. For the development of hydrogen permeable membrane, palladium was deposited on porous stainless steel support by electroless plating method. In this work, the activation effect on the surface of stainless steel support has been investigated for the effective palladium plating. The morphology and microstructure were characterized by SEM and the composition was analyzed by EDX. It is found that the composition of deposited nuclei on the stainless steel support was changed in accordance with activation cycles. It is also observed that Sn-enriched nuclei has been changed to Pd-enriched nuclei over the fifteenth activation. The uniform deposition of the dense palladium layer on porous stainless steel support has been performing with Sn-enriched nuclei and comparing with Pd-enriched nuclei.

• 대한물리의학회지
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• 제9권3호
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• pp.249-253
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• 2014

PURPOSE: This study intends to examine the effects of change of anatomical position of the ankle joint in open kinematic chain, an appropriate position for selective muscle training, on vastus lateralis obliques, rectus femoris, vastus medilais obliques, and rectus abdominalis muscle activation and to present an effective method of muscle training for patients and normal people. METHODS: The participants of this study were Korean healthy adult in their 20s. The 8 channel surface electromyography was used to measure muscle activation while the subjects raised their legs under each condition. Under each condition, while the subjects raised the leg to hip joint flexion at $60^{\circ}$ along the arch. RESULTS: The analysis result of muscle activation by each section and position during leg rising. There were significant differences. CONCLUSION: For independent strengthening of each muscle, muscle activation was measured according to leg raising angles and the result differed according to each section and position. If this study result is applied to muscle training for patients who need selective muscle training, more effective muscle strengthening will be made possible.

• Corrosion Science and Technology
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• 제6권1호
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• pp.7-11
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• 2007

In this study, new evaluation method for the stability and corrosion resistance properties of passive films has been suggested by means of observation of self-activation process in open-circuit state and galvanostatic nanoscale reduction test. The experiments were performed for air-formed oxide film in case of plain carbon steel, and for anodically passivated films formed in aqueous sulfuric acid solutions in case of titanium and 304 stainless steel. From these experimental results, we derived two parameters, $i_{0}$ and $q_{0}$, which characterize the self-activation process and the properties of passive film on a stainless steel surface. The parameter $i_{0}$ was defined as the rate of self-activation, and $q_{0}$, the reduced amount of charge during the self-activation process. In conclusion, it is considered that the stability and corrosion resistance of passive metals and alloys can be evaluated quantitatively by three parameters of $\tau_{0}$, $q_{0}$, and $i_{0}$, which easily obtain by means of observing the self-activation process and galvanostatic nanoscale reduction test.

• The Journal of Korean Physical Therapy
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• 제35권2호
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• pp.53-57
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• 2023

Purpose: The purpose of this study was to compare the changes in the muscle activation of the quadriceps muscle (rectus femoris, vastus lateralis, vastus medialis) during the stand-to-sit (StandTS) movement according to the plantar flexion angle of the ankle joint. Methods: A total of 22 healthy young females participated in this study. During the StandTS under the three conditions (plantarflexion angle 0°, 20°, and 45° of the ankle), electromyography (EMG) data (% maximum voluntary iso¬metric contraction) of the rectus femoris, vastus lateralis, and vastus medialis were recorded using a wireless surface EMG system. Results: There was a significant difference in the muscle activation of rectus femoris, vastus lateralis, and vastus medialis according to the plantar flexion angle (0°, 20°, and 45°) of the ankle. The muscle activation of the quadriceps was the highest at a 45° angle of plantarflexion and the lowest at 0°. One-way repeated ANOVA was used to analyze the muscle activation data of the lower extremity muscles according to the angle of the ankle joint. Conclusion: Based on the results of our study, it was confirmed that the muscle activity of the quadriceps can be increased even in the StandTS movement, which involves the eccentric contraction of the quadriceps muscle. This suggests that maintaining a plantar flexion posture for a long time, say by wearing high-heeled shoes, can quickly cause muscle fatigue in the lower-limb muscles, which can cause a decrease in balance ability leading to falls.

• 폴리머
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• 제36권6호
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• pp.739-744
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• 2012

본 연구에서는 합성한 styrene-acrylonitrile(SAN) 전구체를 기반으로 한 탄소를 제조하였다. 그 제조된 탄소는 화학적 환원법으로 활성화하였고, 그 활성화된 SAN 기반 탄소를 A-SAN이라 명명하였다. 전기이중층 커패시터의 전극용 A-SAN 기반 탄소의 표면 특성과 전기화학적 특성에 있어서 활성화 온도에 의한 효과를 확인하기 위해 다양한 온도에서 활성화를 진행하였다. A-SAN의 특성분석을 위해 X-선 회절분석법(XRD), 주사전자현미경(SEM) 그리고 비표면적 장치에 의해 조사되었다. 또한 전기화학적 거동은 순환전류전압과 정전류 충방전법으로 측정하였다. 그 실험 결과로부터, A-SAN 700이 우수한 전기화학적 특성과 가장 높은 비축전용량 값을 보였지만, 활성화 온도가 $700^{\circ}C$가 넘으면 이러한 특성들은 감소했다. 이것은 $700^{\circ}C$ 이상의 온도에서의 활성화가 마이크로 기공 구조의 변형을 야기하기 때문인 것으로 사료된다.

• 공업화학
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• 제28권6호
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• pp.649-654
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• 2017

제주도에서 다량 발생하고 있는 폐감귤박을 활성화제로 KOH를 사용하여 활성탄을 제조하였고, 제조된 활성탄의 특성을 검토하였다. KOH 침적비율(100~300%), 활성화 온도($400{\sim}900^{\circ}C$) 및 활성화 시간(0.5~1.5 h)의 조건에서 각 조건이 증가할수록 요오드 흡착능은 증가하였으나 활성탄의 수율은 감소하였다. 그리고 활성화 시간의 경우 1.5 h 이상에서는 요오드 흡착능 및 활성탄 수율에서 비슷하였다. 또한 KOH 침적비율이 증가할수록 비표면적 및 세공부피는 증가하였으나 세공크기는 감소하였으며, 제조된 평균 세공크기는 $20{\sim}25{\AA}$이었다. KOH의 침적비율 300%, 활성화 온도 $900^{\circ}C$, 활성화 시간 1.5 h에서 제조된 활성탄은 비표면적 및 요오드 흡착능이 각각 $1,527m^2/g$ 및 1,246 mg/g으로 가장 높았다.

• 자원리싸이클링
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• 제14권1호
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• pp.47-54
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• 2005

본 연구에서는 농산물 폐기물인 국산 포도씨를 원료로 사용하여 roasting, cabonization, chemical activation 과정을 각각 거쳐 활성탄을 제조하였다. 화학적 활성화는 NaOH, KOH, ZnCl$_2$를 활성화제로 사용하였다. 100-300wt%의 중량비율로 활성화하여 제조된 활성탄의 N$_2$-BET 비표면적은 44.09~121.33 m$^2$/g으로 측정되었다. 포도씨 활성탄에 메틸렌 블루를 흡착 시킨 후 UV spectrometer를 사용하여 투광도를 측정하였으며, 투광도 측정 시 메틸렌 블루의 최대 흡광파장은 660 nm로 설정하였다. 그 결과 메틸렌블루의 흡착은 NaOH 활성화제를 사용하여 제조한 활성탄에서 가장 잘 이루어졌으며, 평형 흡착 시간은 60분인 것으로 나타났다.

• 한국수소및신에너지학회논문집
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• 제8권4호
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• pp.181-185
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• 1997

The electrochemical properties of the $AB_2$-type (Zr-Ti-V-Ni-Cr-Co-Mn) metal hydride electrodes prepared by ball milling with $AB_5-type\{(LM)Ni_{3.6}Al_{0.4}Co_{0.7}Mn_{0.3}\}$(LM : Lanthanum-rich mischmetal) alloy powder as a surface activator were investigated. By ball milling with $AB_5$ type alloy powder, the activation of $AB_2$ type metal hydride electrode was accelerated resulting in an increase of discharge capacity from 35% to 85% of the maximum capacity at the first cycle. As the amount of surface activator increased the activation rate increased, whereas the discharge capacity increased with 10wt% and decreased with 20wt% addition of the surface activator. When the amount of the surface activator was kept constant as 10wt%, the discharge capacity and the activation rate increased with ball milling time up to 20 hours. However beyond 20 hours of ball milling time, they decreased drastically due to the nano-crystallization or amorphorzation of the alloy powder.

• 한국표면공학회지
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• 제44권4호
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• pp.131-136
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• 2011

A kinetic study has been made for the growth of nanocrystalline diamond (NCD) particles to a continuous thin film on silicon substrate in a microwave plasma chemical vapor deposition reactor. Parameters of deposition have been microwave power of 1.2 kW, the chamber pressure of 110 Torr, and the Ar/$CH_4$ ratio of 200/2 sccm. The deposition has been carried out at temperatures in the range of $400\sim700^{\circ}C$ for the times of 0.5~16 h. It has been revealed that a continuous diamond film evolves from the growth and coalescence of diamond crystallites (or particles), which have been heterogeneously nucleated at the previously scratched sites. The diamond particles grow following an $h^2$ = k't relationship, where h is the height of particles, k' is the particle growth rate constant, and t is the deposition time. The k' values at the different deposition temperatures satisfy an Arrhenius equation with the apparent activation energy of 4.37 kcal/mol or 0.19 eV/ atom. The rate limiting step should be the diffusion of carbon species over the Si substrate surface. The growth of diamond film thickness (H) shows an H = kt relationship with deposition time, t. The film growth rate constant, k, values at the different deposition temperatures show another Arrhenius-type expression with the apparent activation energy of 3.89 kcal/mol or 0.17 eV/atom. In this case, the rate limiting step might be the incorporation reaction of carbon species from the plasma on the film surface.