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        검색결과 17

        1.
        2023.11 구독 인증기관·개인회원 무료
        The process of carbonization followed by a high-temperature halogenation removal of radionuclides is a promising approach to convert low-radioactivity spent ion-exchange (IE) resins into freereleasable non-radioactive waste. The first step of this process is to convert spent ion-exchange resins into the carbon granules that are stable under high-temperature and corrosive-gas flowing conditions. This study investigated the kinetics of carbonization of cation exchange resin (CER) and the changes in structures during the course of carbonization to 1,273 K. Both of model-free and modelfitted kinetic analysis of mixed reactions occurring during the course of carbonization were first conducted based on the non-isothermal TGAs and TGA-FTIR analysis of CER to 1,272 K. The structural changes during the course of carbonization were investigated using the high-resolution FTIR and C-13 NMR of CER samples pyrolyzed to the peak temperature of each reaction steps established by the kinetic analysis. Four individual reaction steps were identified during the course of carbonization to 1,273 K. The first and the third steps were identified as the dehydration and the dissociation of the functional group of —SO3-H+ into SO2 and H2O, respectively. The second and the fourth steps were identified as the cleavage of styrene divinyl benzene copolymer and carbonization of pyrolysis product after the cleavage, respectively. The temperature and time positions of the peaks in the DTG plot are nearly identical to those of the peaks of the Gram Schmidt intensity of FTIR. The structural changes in carbonization identified by high-resolution FTIR and DTG are in agreement with those by C-13 NMR. The results of a detailed examination of the structural changes according to NMR and FTIR were in agreement with the pyrolysis gas evolution characteristics as examined by TGA-FTIR.
        2.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Water disinfection using UV-LED(Light emitting diode) has many advantages, such as smaller footprint and power consumption as well as relatively longer lifespan than those of conventional mercury-UV lamps. Moreover, UV-LED disinfection is considered an environmentally benign process due to its mercury-free nature. In this study, disinfection using an LED module emitting 275nm UV was carried out. 384 UV-LEDs were put into a cylinder tube with a capacity of 1.7 liters. The UV intensity of the UV-LED module was controlled from 1.7 to 8.4 mW/cm2. The disinfection efficiency for the model microorganism solutions(E. coli ) was monitored. As the UV intensity(I) and contact time(t) varied, inactivation of the microorganisms from 2 to 4-log-removals(i.e., 99 to 99.99% of disinfection efficiency) was achieved. Disinfection using UV-LED was followed to 1st order reaction and the reaction rate constant, k was determined. In addition, the relationship between UV intensity(I) and contact time(t) in order to obtain 99.99% of disinfection efficiency was modeled: I1.2∙𝑡= 460, which indicates that the product of UV intensity and contact time requiring 4-log-removals is always constant.
        4,000원
        3.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구의 목적은 딥 스쿼트 동작 시 발목 관절 유연성이 무릎 관절의 운동역학적 요인들간의 관련성을 분석하는데 있었다. 본 연구는 최근 1년간 하지 근골격계 병력이 없는 성인 남성 19명과 여성 8명이 연구대상자로 참여하였다. 딥 스쿼드 시 발목 관절 유연성과 하지 관절의 운동역학적 요인들과 상관관계를 검증하기 위해 pearson의 적률상관계수(pearson’s correlation coefficient)를 이용하였고(SPSS 24.0, Armonk, NY, USA), 통계적으로 유의미한 상관성을 나타낸 변인들은 단순회기분석(simple regression analysis)을 실시하였으며, 유의 수준은 .05로 설정하였다. 본 연구를 통해 발목 관절 유연성과 무릎 관절의 압력을 결정하는 최대 관절모멘트와 관절반발력 요인들 간의 관련성을 확인할 수 있었다. 그러므로 근력 트레이닝 시 딥 스쿼트와 같은 무릎 관절에 많은 부하를 발생시킬 수 있는 운동을 적용할 때 개인에 신체적 특성 중 발목 관절의 유연성의 정도를 확인하는 것은 신체의 안정성과 무릎 관절의 상해 위험성을 감소시킬 수 있는 운동 강도를 설정하는데 도움이 될 수 있을 것으로 기대한다.
        4,000원
        4.
        2012.12 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to compare 10 Badminton players with 10 common students on smash motions. These smash motions were analyzed by a three-dimensional image analysis and kinetic variables were calculated by using a ground reaction force system to
        6,400원
        5.
        2011.12 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to compare Men's high school tennis player's before-player serve and rear-player serve. Such serve movements were analyzed in three-dimensional image analysis, kinetic variables were calculated using force platform to underst
        6,600원
        6.
        2011.12 구독 인증기관 무료, 개인회원 유료
        The objectives of this study were to make comparative kinematic and kinetic analysis on major motions in clean & jerk and snatch of weight lifting and to systematize the results for enhancing the athletic performance of male middle school students beginni
        5,200원
        7.
        2011.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Twenty four fractions by solvent extraction and/or acid precipitation from fruit body and culture broth of Inonotus obliquus were prepared, and their inhibitory effect against acetylcholinesterase (AChE) was investigated. Among these fractions, acid (1 M HCl) precipitates from cell-free culture broth and fruit body exhibited the highest inhibitory effect on AChE in vitro. Acid precipitates inhibited AChE activity in a concentration-dependant manner and IC50 values of both acid precipitates were 0.53 mg/mL. The inhibition pattern was general non-competitive inhibition. The energetic parameters were also determined by dual substrate/temperature design. Both acid precipitates increased the values of Ea, ΔH, ΔG and ΔH* decreasing the value of ΔS for AChE. The results implied that the acid precipitates from I. obliquus increased the thermodynamic barrier, leading to the breakdown of ES complex and the formation of products as inhibitory mechanism.
        4,000원
        8.
        2010.12 구독 인증기관 무료, 개인회원 유료
        The aim of this study is to offer scientific materials and effective teaching methods of place kick motions of high school students by comparing and analyzing kinetic and motor mechanical variables of experts and beginners’ place kicks which are usually u
        5,800원
        9.
        2009.12 구독 인증기관 무료, 개인회원 유료
        This study is conducted to examine kinematic and kinetic variables influencing on vertical jump records. To this end, as the subjects of the study, three male volleyball players and three general students vertically jumped five times, and the study compar
        4,000원
        10.
        2009.12 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to analyze the kinematic variables due to the course change in the first serve of high school girl tennis athletes using three dimensional video analysis and to produce kinetic variables using ground reaction force to understa
        5,800원
        11.
        2008.12 구독 인증기관 무료, 개인회원 유료
        The purpose of this study were to offer the scientific data of the right and left feet's kick motion of the ROK high school boy students and to seek out the effective method of instruction, througth comparing and analyzing the variation aspects of the kin
        5,400원
        13.
        2018.01 KCI 등재 서비스 종료(열람 제한)
        Biomass as a renewable energy source has several limitations in terms of the potential for steady supply and its thermal characteristics. This study conducted a thermal weight change analysis and determined its kinetics to address this problem. Sawdust was chosen as the biomass, and PE and PP were the plastics used. Based on the result of thermogravimetric analysis (TGA), the kinetic characteristics were analyzed using Kissinger, Ozawa, and Friedman methods, which are the most common methods used to obtain reaction coefficients and activation energy. The methods used to determine the thermal degradation kinetics were considered feasible for evaluating the pyrolytic behavior of the materials tested. The experimental results of this study provided insights into mixed biomass/plastics pyrolysis kinetics and their optimal operation conditions.
        14.
        2017.06 서비스 종료(열람 제한)
        본 연구는 총 여덟 가지 실외원예활동 동작의 운동학 및 운동역학적 특성을 분석하기 위해 수행되었다; 땅고르기, 땅파기, 종자파종, 모종 심기, 근거리 잡초뽑기, 원거리 잡초뽑기, 저위치 수확하기, 고위치 수확하기. 20대 남자 대학생 총 24명(평균 연령 : 23.4 ± 2.93세)이 본 연 구에 참여하였다. 삼차원 동작분석 시스템(Qualisys Track Manager 2.7 build 783)과 지면반력기기(Kistler Instruments)를 이용하여 무게 중심, 관절각도와 같은 운동학적 요인과 지면반력, 압력중심, 관절모멘트와 같은 운동역학적 요인을 측정하였다. 또한 표면 근전도기기 (Desktop DTS)를 이용하여 총 16개 양측 몸통과 하지근육의 근육활성도를 측정하였다. 그 결과 총 여덟 가지의 실외원예활동 동작은 1) 한 발 내딛기(예 : 땅고르기, 땅파기), 2) 쭈그려 앉기(예 : 종자파종, 모종심기, 근거리 잡초뽑기, 원거리 잡초뽑기), 3) 허리 구부리기(예 : 저위 치 수확하기, 고위치 수확하기)로 구분되었다. 각 동작은 다시 세 개 또는 네 개의 구간으로 세분화되었다. 원예활동 동작 수행 시 무게중심 은 전·후 방향과 상·하 방향으로 이동하였다. 전·후 방향으로 무게중심 이동이 가장 많은 원예활동은 땅고르기였고, 상·하 방향으로 가장 많은 무게중심 이동이 나타나는 원예활동은 종자파종이었다(p = 0.001). 무게중심 이동으로 불안정해진 신체균형을 유지하기 위한 보상적 움직임으로 지면반력 발생, 압력중심 이동, 하지 관절과 근육의 결합운동이 발생했다. 총 여덟 가지 실외원예활동은 원예활동 수행방법에 따라 운동학 및 운동역학적 특성의 차이를 보였다(p = 0.05). 따라서 본 연구의 결과는 노인과 재활환자의 균형감 향상을 위한 원예치료 프 로그램 개발 시 유용한 기초자료로서 활용되어 질 것이다.
        15.
        2016.11 서비스 종료(열람 제한)
        Anaerobic digestion is one of the most economical ways to treat organic wastes; the production of excessive sludge is limited; aeration is not required; operation cost is low; valuable energy resource (methane) is produced. However, propionate, an intermediate substance during the process, is known to inhibit biochemical process at high concentration; but it is difficult to be degraded biologically as its oxidation is thermodynamically unfavorable (△G>0). However, there are several microorganisms which could oxidize propionate fully by their syntrophic association. Therefore, in this research, the propionate enrichment culture was produced in large amount (~1L), and the main players which are responsible for utilizing propionate are identified. Furthermore, the kinetic parameter was obtained from this research. Seed came from two different full-scale anaerobic digesters which is located in Joongrang (JR) and Sincheon (SC). 16s rRNA gnee based metagenomics results indicated that Smithella propionica and Methanobacterium beijingense were the most dominant species in all seeds. The fact that bacterial family Syntrophomonadaceae and archaeal genus Methanosaeta were also found significantly in all seeds means that there might be symbiotic relationship among propionate oxidizing bacteria, butyrate oxidizing bacteria, hydrogenotrophic methanogens and acetotrophic methanogens in complete oxidation of propionate. Based on the first order kinetic which indicated propionate degrading rate, k (1/day) on JR and SC was represented 0.0243 and 0.0223, respectively. Also, based on Modified-Gompertz model, umax on JR and SC was represented as 0.024 and 0.016, respectively.
        16.
        2008.10 KCI 등재 서비스 종료(열람 제한)
        국토해양부에서는 해양 DGPS 기준국가 연계하여 전국망 위성항법보정시스템(NDGPS) 구축 사업을 추진 중에 있으며, 2008년 춘천기준국이 설치 완료되면 우리나라 전역에서 실시간 DGPS 측위 정보를 이용할 수 있다. 따라서 DGPS 측위 정보의 이용 활성화를 위하여 DGPS의 측위 정확도를 측정 분석하였다. 실시간 DGPS 측위 정확도는 정적 측정시 평면상 RMS(Root Mean Square) 오차는 0.42m, 동적 측정시 평변상 RMS 오차는 0.48m로 분석되었으며, RTK에 의한 비교 측정 분석도 병행하였다. 그 결과 위성항법보정시스템(DGPS)은 높은 정확도를 요하는 GIS구축사업 분야에 직접적으로 이용될 수 없으나, 실시간 측위 정보를 필요로 하는 GIS활용 분야에서는 DGPS가 다양하게 이용될 수 있을 것이다.
        17.
        2000.06 KCI 등재 서비스 종료(열람 제한)
        A kinetic study for nitrate removal by anion exchange resin was performed using continuous column reactors. Kinetic approach from the packed bed showed the reaction rate constant k1 was 0.07∼0.17 ℓ/㎎·hr and maximum exchange quantity q0 was 27.75∼31.81 ㎎/g. The results from the continuous column well agreed with that from the batch reactor. An economic analysis of the water treatment plant by anion exchange resin with a regenerating system was performed to design plant and process. Based on the treatment of 20 ㎎/ℓ nitrate-contained wastewater of 10,000 gallons per day to 2 ㎎/ℓ , total capital cost and total annual cost are estimated to be 836 million wons and 211 million wons, respectively.