• 한국전기전자재료학회논문지
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• 제29권1호
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• pp.17-22
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• 2016

The activation energy of a material is an important factor that significantly affects the lifetime and can be used to develop a degradation model. In this study, a thermal analysis was carried out to evaluate and collect quantitative data on the degradation of insulation materials like EPR and CSP used for nuclear power plant cables. The activation energy was determined from the relationship between log ${\beta}$ and 1/T based on the Flynn.Wall.Ozawa method, by a TGA test. The activation energy was also derived from the relationship between ln(t) and 1/T based on isothermal analysis, by an OIT test. The activation energy of EPR derived from thermal analysis was used to calculate the accelerated aging time corresponding to the number of years of use, employing the Arrhenius equation, and determine the elongation corresponding to the accelerated aging time.

• 대한환경공학회지
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• 제22권1호
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• pp.133-139
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• 2000

리그닌의 열분해반응 후 발생하는 잔류고형물을 활용해보고자 $ZnCl_2$로 활성화하여 활성탄을 제조하였다. 공정변수로 설정한 활성화 온도, 활성화 시간 및 활성화제의 첨가량 등이 활성탄의 세공구조와 비표면적에 미치는 영향을 조사하여 최적 활성화 조건을 구하였다. 리그닌의 열분해 잔류고형물에 활성화제인 염화아연을 300wt% 첨가한 것을 질소분위기에서 $1000^{\circ}C$로 1시간 동안 활성화시켰을 때 비교적 높은 비표면적과 흡착능을 가지면서 세공구조가 잘 발달된 활성탄을 제조할 수 있었다.

• 한국운동역학회지
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• 제26권4호
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• pp.421-426
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• 2016

Objective: The purpose of this study was to investigate how different levels of compression exerted on the femoral region (known as the power zone) by coated fabric influences the activation and anaerobic capacity of the rectus femoris. Method: Three different levels of compression on the rectus femoris of the participants, namely 0% (normal condition), 9% (downsize), and 18% (downsize), were tested. The material of the fabric used in this study was nonfunctional polyurethane. Surface electromyography test was used to investigate the activation of the rectus femoris, while the isokinetic test (Cybex, $60^{\circ}/sec$) and Wingate test were used to investigate the maximum anaerobic power. Results: The different compression levels (0%, 9%, and 18%) did not improve the strength and anaerobic capacity of the knee extensor. However, knee flexor interfered with activation of the biceps femoris, which is an agonist for flexion, during 18% compression. Conclusion: Compression garments might improve the stretch shortening cycle effect at the time of eccentric contraction and during transition from eccentric to concentric contraction. Therefore, future studies are required to further investigate these findings.

• 한국방사선학회논문지
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• 제13권1호
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• pp.45-53
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• 2019

본 연구는 의료용 선형가속기 시설을 차폐하는 콘크리트에 대한 중성자 방사화 연구로써, 일반 콘크리트와 저 방사화 콘크리트를 비교 분석하였다. 실험 방법은 MCNPX (Ver. 2.5.0)와 FISPACT-2010를 사용하여 모의실험을 진행하여, 광자선과 중성자선에 대한 차폐능을 산정하고 중성자 방사화 평가를 진행하였다. 그 결과 차폐능은 일반 콘크리트에서 20~50 cm 효율적이였으며, 방사화 평가의 경우 저 방사화 콘크리트에서 방사능이 낮게 계산되었으나, 모두 자체처분허용 농도를 초과하지 않는 수준으로 산정되었다. 이를 종합적으로 분석한 결과 일반 콘크리트를 사용하는 것이 효율적인 것으로 판단된다.

• The Journal of Korean Physical Therapy
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• 제34권4호
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• pp.187-191
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• 2022

Purpose: The purpose of our study aimed to identify the effect of static and dynamic bridge exercise with gym ball using gym ball on muscle activation of trunk and lower-limb in healthy individuals. Methods: A total of 20 healthy adults participated in this study. The individuals performed general bridge exercise, static and dynamic bridge exercise using gym ball. During the three methods of bridge exercises, electromyography (EMG) data (% maximum voluntary isometric contraction) of the rectus abdominis, erector spinae, biceps femoris, and gastrocnemius were recorded using a wireless surface EMG system. Results: Rectus abdominis activation showed significantly greater during dynamic bridge exercise compared with general bridge exercise and dynamic bridge exercise. Erector spinae, biceps femoris, and gastrocnemius were greater during static and dynamic bridge exercise compared with general bridge exercise. Conclusion: Based on our results, bridge exercise using gym ball, particularly integrating lower-limb movement, could be a useful method to enhance muscle activation of trunk and lower-limb (rectus abdominis, erector spinae, biceps femoris, and gastrocnemius).

• Nuclear Engineering and Technology
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• 제54권12호
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• pp.4684-4692
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• 2022

Radionuclide identification is an important part of the nuclear material identification system. The development of artificial intelligence and machine learning has made nuclide identification rapid and automatic. However, many methods directly use existing deep learning models to analyze the gamma-ray spectrum, which lacks interpretability for researchers. This study proposes an explainable radionuclide identification algorithm based on the convolutional neural network and class activation mapping. This method shows the area of interest of the neural network on the gamma-ray spectrum by generating a class activation map. We analyzed the class activation map of the gamma-ray spectrum of different types, different gross counts, and different signal-to-noise ratios. The results show that the convolutional neural network attempted to learn the relationship between the input gamma-ray spectrum and the nuclide type, and could identify the nuclide based on the photoelectric peak and Compton edge. Furthermore, the results explain why the neural network could identify gamma-ray spectra with low counts and low signal-to-noise ratios. Thus, the findings improve researchers' confidence in the ability of neural networks to identify nuclides and promote the application of artificial intelligence methods in the field of nuclide identification.

• 한국산학기술학회논문지
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• 제13권2호
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• pp.947-953
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• 2012

본 연구에서는 폐타이어 열분해 잔류물(char)을 이용하여 활성탄을 제조하기 위한 연구를 수행하였다. 활성탄 제조는 고정층 석영관 반응기에서 수증기를 이용한 물리적 활성화 방법을 사용하였으며, 주요한 실험 변수는 활성화 온도, 활성화 시간, 승온속도 및 활성화제의 주입량 등이다. 활성탄 제조 후 세공분포를 분석한 결과, 활성화 온도 $850^{\circ}C$, 승온속도 $5^{\circ}C$/min, 활성화 시간 3 hr의 조건에서 제조한 활성탄이 미세세공(micropore), 중간세공(mesopore) 및 거대세공(macropore)이 가장 많이 발달함을 알 수 있었다. 본 연구결과, 폐타이어 열분해 잔류물을 이용한 활성탄 제조의 최적 조건은 활성화 온도 $850^{\circ}C$, 활성화 시간 3 hr, 승온속도 $5^{\circ}C$/min, 활성화제 공급량 3 g $H_2O/char-g{\cdot}hr$ 등으로 조사되었다. 이 조건에서 제조한 활성탄의 BET 비표면적은 $517.6m^2/g$, 총 세공부피 $0.648cm^3/g$으로 나타나 활성탄으로서의 사용 가능성을 확인할 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제20권10호
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• pp.1510-1516
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• 2007

These experiments were carried out to optimize the parameters of electrical activation, methods of parthenogenetic activation and embryo culture in vitro and meanwhile to isolate embryonic stem cells-like (ESCs) derived from porcine parthenogenetic blastocysts (pPBs). These results showed that, as the electric field strength increased from 1.0 to 2.7 kV/cm, the cleavage rate of parthenogenetic embryos increased gradually but the rate of oocyte lysis was significantly increased when using 2.7 kV/cm field strength. The rate of cleavage in 2.2 and 2.7 kV/cm groups was significantly increased in comparison with that of the 1.0 kV/cm group. A voltage field strength of 2.2 kV/cm DC was used to investigate blastocyst development following activation with a single pulse of 30 or $60-{\mu}sec$ pulse duration. The optimum pulse duration was 30-${\mu}sec$, with a blastocyst rate of 20.7%. Multiple pulses were inferior to a single pulse for blastocyst yield (8.0% vs. 29.9) (p<0.05). For porcine oocyte parthenogenetic activation methods, the rates of cleavage (79.0% vs. 59.8%) and blastocysts (19.4% vs. 3.4%) were significantly increased in electrical activation in contrast to chemical activation with ionomycin/6-DMAP (p<0.05). Rates of cleavage and blastocyst formation in NCSU-23 and PZM-3 embryo media were higher than those of G1.3/G2.3 serial culture media, but there was no significant difference among the three groups. The total cell number of blastocysts in PZM-3 embryo culture media containing $5{\mu}g/ml$ insulin was significantly higher than that of the control (no insulin) ($44.3{\pm}9.1$ vs. $33.9{\pm}11.7$). For isolation of PESCs-like, the rates of porcine blastocysts attached to feeder layers and ICM colony formation in Method B (nude embryo culture) were better than those in Method A (intact embryo culture).

• 분석과학
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• 제14권4호
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• pp.1075-1081
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• 2001

기기중성자방사화 분석법은 핵 분석기술의 대표적인 방법으로 비파괴-동시 다원소분석의 장점과 함께 절대측정값에 의해 정량 할 수 있다는 특징을 갖고 있다. 최근에는 정확도와 편의성을 만족할 수 있는 $k_0$-정량법을 사용한 기기중성자방사화 분석법이 세계적으로 일반화되고 있다. 본 연구에서는 $k_0$-법의 적용을 위하여 이 방법의 전체적인 개념의 소개와 함께 $k_0$-파라미터를 측정하고자 하였다. 이를 위하여 $k_0$-법의 개념이해와 정량에 필요한 인자들의 정의 및 파라미터인 $Q_0$(${\alpha}$)와 f 값을 결정하기 위한 수식과 실험적 측정방법 등을 요약하였고 중성자조사공에 따라 특성 값을 갖는 ${\alpha}$와 f 값을 하나로 연구용원자로의 방사화분석용 조사공(NAA#1)에서 측정하여 $k_0$-법의 도입을 위한 기반을 마련하였다.

• 한국독성학회:학술대회논문집
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• 한국독성학회 1997년도 국제 심포지움 및 춘계 학술대회
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• pp.65-74
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• 1997

By using guinea pig lung mast cells, this study aimed to examine the effects of Aloe component(NY945) on the mediator releases caused by mast cell activation, and also aimed to assess the effects of NY945 on the mechanism of mediator releases in the mast cell activation. We partially purified mast cells from guinea pig lung tissues by using the enzyme digestion, the rough and the discontinuous density percoll gradient method. Mast cells were sensitized with $IgG_1$ (anti-OA) and challenged with ovalbumin. Histamine was assayed by fluorometric analyzer, leukotrienes by radioimmunoassay The phospholipase D activity was assessed more directly by the production of labeled phosphatidylethanol or phosphatidylbutanol which was produced by phospholipase D-mediated transphosphatidylation in the presence of ethanol or butanol. The amount of mass 1,2-diacylglycerol was measured by the [$^3H$]1,2-diacylgycerol produced when prelabeled with [$^3H$]myristic acid. In the mast cells prelabeled with L-[$^3H$]methyl methionine the phospholipid methylation was assessed by measuring the incorporation of the [$^3H$]methyl moiety into phospholipids. Pretreatment of NY945(10$\mu$g) significantly decreased histamine and leukotrienes releases during mast cell activation. The decrease of histamine release was stronger than that of leukotrienes during mast cell activation. The phospholipase D activity increased by the mast cell activation was decreased by the dose-dependent manner in the pretreatment of NY945. The amount of mass 1,2-diacylglycerol produced by activation of mast cells were decreased in the pretreatment of NY945. NY945 pretreatment strongly inhibited the incorporation of the [$^3H$]methyl moiety into phospholipids. The data suggest that NY945 purified from Aloe inhibits in part an increase of 1,2-diacylglycerol which is produced by activating mast cells with antigen-antibody complexes which is mediated via phosphatidylcholine-phospholipise D and phosphatidylinositole-phospholipise C systems, and then followed by the inhibition of histamine release. Furthermore, NY945 reduces the phosphatidylcholine production by inhibiting the methyltransfsrase I and II, which decrease the conversion of phosphatidylcholine into arachidonic acid and inhibits the production of leukotrines.