• 대한환경공학회지
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• 제29권5호
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• pp.515-520
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• 2007

현재 슬러지의 처리는 주로 해양투기에 의해 진행되는데 런던협약에 의해 슬러지 내 중금속 함량에 따라 점진적으로 해양투기가 완전 금지되어진다. 이에 하수슬러지의 안정적 처리 방안이 시급히 검토되어야 한다. 그 대책으로 최근 슬러지의 능률적이고 친환경적인 처리를 위한 방법 중 하나로 활성화를 통한 흡착제 제조가 부각되고 있다. 본 연구는 하수슬러지를 수증기 활성화법을 이용하여 흡착제로 활용하기 위한 기초연구로서 양질의 흡착제를 제조하기 위한 변수별 연구를 통한 최적 활성화조건을 연구하였다. 그 결과 요오드 흡착능을 기준으로 하여 변수별 연구를 통해 수증기 주입량 30 mL/hr, 활성화 온도 $500^{\circ}C$, 활성화 시간 60분으로 선정되었다. 이 때 요오드 흡착능과 수율은 228.4 mg/g, 77.23%로 나타났다. 또한 질소 흡착, SEM, EDS를 이용하여 수증기 활성화에 따른 세공 발달, 비표면적, 평균 세공경 및 화학적 성상과 함량을 파악하였다. 수증기 활성화를 통해 발달되는 세공은 주로 미세 세공임을 확인하였다.

• Physical Therapy Rehabilitation Science
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• 제6권4호
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• pp.164-169
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• 2017

Objective: This research investigated the effects of simple visual imagery and mental rotation imagery on neural activity of adults who are at high risk of smart phone addiction by measuring their electroencephalography (EEG). Design: Cross-sectional study. Methods: Thirty people with a high risk of smart phone addiction was selected and then were evaluated for their neural activation patterns using EEG after reminding them about simple visual imagery and mental rotation imagery. A simple visual image was applied for 20 seconds using a smartphone. This was followed by a resting period of 20 seconds. Mental rotation imagery was applied for 20 seconds. During mental rotation imagery, the rotational angle was selected at random. We compared activation patterns according to the analyzed EEG with hemisphere reminding them about imagery. Results: On the EEG, theta rhythm from the left hemisphere parietal area increased when the subjects were reminded of mental rotation imagery, and sensorimotor rhythm from close to the left hemisphere area increased when the subjects were reminded of simple visual imagery. Conclusions: Neural activation from the left hemisphere occurs for motor imagery in adults who are at high risk of smart phone addiction. These results identify a neural mechanism of adults who a have high risk of smart phone addiction, which may provide contribute to the development of motor rehabilitation for smartphone users.

• Investigative Magnetic Resonance Imaging
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• 제3권1호
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• pp.53-59
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• 1999

목적 : 언어기능의 지도화(language mapping) 및 우세반구 결정에 있어서 기능적 자기공명영상의 유용서을 알아보고자 하였다. 대상 및 방법 : 자원자 10명(남자 6명, 여자 4명, 오른손잡이 7명, 왼손잡이 3명)을 대상으로 단어생성 과제(명사만들기, 동사만들기)와 판단과제를 이용하여 언어영역의 활성화를 유도하였다. 1.5T 초진도 자기공명영상장치에서 EPI로 BOLD 기법을 이용하여 기능적 영상을 얻었으며, 여앙후처리는 SPM 분석 프로그램을 이용하였다. 기능적 영상은 2번의 활성기와 3번의 휴식기를 번갈아 시행하였고 스캔 시간은 각각30초였으며 총 영상획득시간은 162초였다. 유의수준 p<0.001을 기준ㅇ로 자극 과제에 따라 활성화된 뇌영역을 분석하였고 반구별로 활성화된 화소의 수를 측정하여 편재화지수(lateralization index)를 구하였다. 결과 : 왼손잡이 1명을 제외한 9명에서 성공적으로 기능적 영상을 얻었으며 양측 전운동영역(premotor area), 하전두회, 두정엽, 중측두회 등의 여러 영역에서 활성화 신호가 나타났다. 오른손잡이의 경우 편재화지수는 평균 0,64(0.16~1)로 모두 좌측으로 편재화 되었다. 과제별로는 동사만들기 과제가 명사만들기 및 판단 과제에 비해 언어 영역의 활성화가 많았고 편재화지수의 값도 높았다. 결론 : 기능적 자기공명영상은 언어영역의 뇌기능지도화 및 우세반구 결저에 있어서 유용한 검사 방법이 될 수 있으리라 생각된다.

• Carbon letters
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• 제11권3호
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• pp.224-234
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• 2010

Four activated carbons were produced by two-stage process as followings; semi-carbonization of indigenous biomass waste, i.e. cotton stalks, followed by chemical activation with KOH under various activation temperatures and chemical ratios of KOH to semi-carbonized cotton stalks (CCS). The surface area, total pore volume and average pore diameter were evaluated by $N_2$-adsorption at 77 K. The surface morphology and oxygen functional groups were determined by SEM and FTIR, respectively. Batch equilibrium and kinetic studies were carried out by using a basic dye, methylene blue as a probe molecule to evaluate the adsorption capacity and mechanism over the produced carbons. The obtained activated carbon (CCS-1K800) exhibited highly microporous structure with high surface area of 950 $m^2/g$, total pore volume of 0.423 $cm^3/g$ and average pore diameter of 17.8 ${\AA}$. The isotherm data fitted well to the Langmuir isotherm with monolayer adsorption capacity of 222 mg/g for CCS-1K800. The kinetic data obtained at different concentrations were analyzed using a pseudo-first-order, pseudo-second-order and intraparticle diffusion equations. The pseudo-second-order model fitted better for kinetic removal of MB dye. The results indicate that such laboratory carbons could be employed as low cost alternative to commercial carbons in wastewater treatment.

• 한국입자에어로졸학회지
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• 제15권4호
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• pp.183-190
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• 2019

Here, we introduce porous graphene balls (PGB) showing superior electrochemical properties as supercapacitor electrode materials. PGB was fabricated via activation of graphene oxides (GO) by H₂O₂ and aerosol spray drying in series. Effect of activation on the morphology, specific surface area, pore volume, and electrochemical properties were investigated. As-prepared PGB showed spherical morphology containing pores, which lead to the effective prevention of restacking in graphene sheets. It also exhibited a large surface area, unique porous structures, and high electrical conductivity. The electrochemical properties of the PGB as electrode materials of supercapacitor are investigated by using aqueous KOH under symmetric two-electrode system. The highest specific capacitance of PGB was 279 F/g at 0.1 A/g. In addition, the high rate capability (93.8% retention) and long-term cycling stability (92.2%) of the PGB were found due to the facilitated ion mobility between the porous graphene layers.

• 한국응용과학기술학회지
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• 제32권3호
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• pp.480-487
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• 2015

In this study, several kinds of active carbons with high specific surface area and micro pore structure were prepared from the coconut shell charcoal using chemical activation method. The physical property of prepared active carbon was investigated by experimental variables such as activating chemical agents to char coal ratio, flow rate of inert gas and temperature. It was shown that chemical activation with KOH and NaOH was successfully able to make active carbons with high surface area of $1900{\sim}2500m^2/g$ and mean pore size of 1.85~2.32 nm. The coin cell using water-based binder in the electrolyte of LiPF6 dissolved in mixed organic solvents (EC:DMC:EMC=1:1:1 vol%) showed better capacity than that of oil-based binder. Also, it was found that the coin cell of water-based binder shows an improved cycling performance and coulombic efficiency.

• 한국농촌건축학회논문집
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• 제17권2호
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• pp.17-26
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• 2015

In this study the location condition and the management of the Rural Experience Tourism Villages located around unified Cheongju city has been surveyed or investigated. On the basis of the results of the survey or investigation this study is to suggest a way to make activate the Rural Experience Tourism Villages which have been inactive. The ways of the research include the understanding of what means the activation of rural areas and then this study is to find the problems with the Rural Experience Tourism Villages and to suggest final ways or plans after the field investigation of the condition of the location and management of the Villages. In this study I had full understanding of the concept of the activation for rural areas and the humanistic and geographical characteristics and then made a wide investigation and analysis of the location condition and the management of the Rural Experience Tourism Villages in this area. Based on the theory and the results of the actual investigation I made a suggestion of basic direction for the improvement of the Villages and the ways for activation of the Villages. I really expect these suggestions of mine to make active contribution to make the actual plan through the promotion of the Rural Experience Tourism Villages.

• 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.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.765-768
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• 2009

In this work, we prepared the activated multi-walled carbon nanotubes (Acti-MWNTs) with well developed physical surface structures, high specific surface area, and higher adsorption capacity by a physical activation process, in order to enhance the hydrogen storage capacity. The Acti-MWNTs' changes in the crystalline phase and in their lattice distortions were characterized by X-ray diffraction (XRD). The textural properties of the Acti-MWNTs were investigated by a nitrogen adsorption isotherms by Brunauer-Emmett-Teller (BET) equation and Harvath-Kawazoe (H-K) calculation, respectively. The hydrogen storage capacity of the Acti-MWNTs was investigated by BEL-HP at 298 K/100 bar. The hydrogen storage capacity of the Acti-MWNTs was improved with the physical activation, resulted from the formation of new hydrogen-favorable sites on the Acti-MWNT surfaces. In conclusion, the physical activation was one of the effective method to enhance the hydrogen storage capacity of the MWNTs.

• 대한환경공학회지
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• 제30권9호
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• pp.900-906
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• 2008

활성탄을 제조하기 위하여 원료물질로서 음식물쓰레기를 이용하였다. 음식물쓰레기를 염화아연으로 약품활성화 하였다. 실험은 서로 다른 약품첨가비율(활성화제/음식물쓰레기), 활성화 온도, 그리고 활성화시간을 변수로 하여 수행하였다. 활성화물의 특성을 나타내기 위하여 요오드가와 메틸렌블루 가, BET 표면적, 세공 용적, 미세공 비율, 세공 직경, 수율 그리고 주사전자현미경 관찰을 수행하였다. 로터리 킬른 반응로를 이용하여 염화아연 함침비 1.0배인 시료를 500$^{\circ}C$에서 60분 동안 활성화하여 제조한 활성화물의 요오드가는 480 mg/g, 메틸렌블루 가는 95 mL/g, BET 표면적은 410 m$^2$/g, 세공 용적은 0.248 cm$^3$/g, 그리고 평균세공직경은 2.43 nm로 나타났다. 제조한 활성탄의 총 표면적중 미세공 면적 비율은 70.7%, 총 세공 용적 중 미세공 용적 비율은 53.2%를 나타냈다.