• Nuclear Engineering and Technology
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• 제52권2호
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• pp.328-336
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• 2020

Cesium is a major product of uranium fission, which is the most commonly existed radionuclide in radioactive wastes. Various technologies have been applied to separate radioactive cesium from radioactive wastes, such as chemical precipitation, solvent extraction, membrane separation and adsorption. Crown ethers and calixarenes derivatives can selectively coordinate with cesium ions by ion-dipole interaction or cation-π interaction, which are promising extractants for cesium ions due to their promising coordinating structure. This review systematically summarized and analyzed the recent advances in the crown ethers and calixarenes derivatives for cesium separation, especially focusing on the adsorbents based on extractants for cesium removal from aqueous solution, such as the grafting coordinating groups (e.g. crown ether and calixarenes) and coordinating polymers (e.g. MOFs) due to their unique coordination ability and selectivity for cesium ions. These adsorbents combined the advantages of extraction and adsorption methods and showed high adsorption capacity for cesium ions, which are promising for cesium separation The key restraints for cesium separation, as well as the newest progress of the adsorbents for cesium separation were also discussed. Finally, some concluding remarks and suggestions for future researches were proposed.

• 한국전문물리치료학회지
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• 제24권4호
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• pp.20-28
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• 2017

Background: Rasch analysis has the advantage of placing both the items and the person along a single ratio scale and calibrates person ability and item difficulty onto an interval scale by logits. Therefore, Rasch analysis has been recommended as a better method for evaluating functional outcome questionnaires than traditional analyses. Objects: The aim of current study was to investigate item fit, item difficulty, rating scale, and separation index of the Korean version of the Fullerton Advanced Balance (KFAB) scale using Rasch analysis. Methods: In total, 93 patients with stroke (male=58, female=35) participated in this study. To investigate the item fit, difficulty, rating scale, and separation index of the KFAB scale, Rasch analysis was completed by the Winsteps software program. Results: In this study, all items of the KFAB scale were included in the Rasch model. The most difficult item was 'standing with feet together and eyes closed', and the easiest item was 'two-footed jump'. The rating scale was a 4-point scale instead of the original 5-point scale. Person and item separation indices showed high values that can identify a person with a wide range of balance ability. Conclusion: The KFAB scale appears to be a reliable and valid tool to assess balance function in patients with stroke. Furthermore, the scale was found to discriminate among stroke patients of varying balance abilities.

• 대한음성학회지:말소리
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• 제48호
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• pp.81-91
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• 2003

In this paper, we propose a speech recognition method based on independent component analysis (ICA) and spectral enhancement techniques. While ICA tris to separate speech signal from noisy speech using multiple channels, some noise remains by its algorithmic limitations. Spectral enhancement techniques can compensate for lack of ICA's signal separation ability. From the speech recognition experiments with instantaneous and convolved mixing environments, we show that the proposed approach gives much improved recognition accuracies than conventional methods.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제28회 춘계학술대회논문집
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• pp.208-211
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• 2007

분리장치란 두개의 구조물을 결합하고 필요에 의해 분리할 수 있는 기능을 가진 장치이다. 본 논문은 이와 같은 기능을 화약의 폭발 및 연소시 발생하는 에너지를 이용하여 수행하는 파이로테크닉 수에 관한 것이다. 화약의 폭발력에 의해 분리가 이루어지는 분리장치로는 폭발볼트가 있다. 폭발볼트의 경우 작동 개념이 단순하고 또한 구성 부품의 수가 적기 때문에 신뢰성 면에서 뛰어나지만 분리시 파편 및 파이로 충격을 동반하는 단점이 있다. 이와 같은 단점을 보완하기 위하여 개발된 것이 가스팽창분리 볼트와 압력카트리지 작동분리장치이다. 이들 장치는 화약의 연소시 발생되는 압력을 이용하기 때문에 분리시 폭발볼트와 같은 악작용은 없지만 폭발볼트에 비해 사이즈가 대형이거나 기계적 결합강도가 작다는 단점이 있다. 따라서 위에 언급된 분리장치들의 작동 원리 및 특성을 이해함으로써 분리장치 설계시 최적의 사양을 선택하는 것이 가능하다.

• Journal of Biosystems Engineering
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• 제28권1호
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• pp.19-26
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• 2003

An oscillating digger mechanism was designed, constructed. and tested. The mechanism is consisted of a six-bar linkage, one four-bar linkage was fer the digger blade and the other one fur variable soil-crop separation. Experimental variables were amplitude(3, 6, 9 mm). frequency(11.2, 14.9. 17.0 Hz), and forward speed of tractor(0.91, 1.13, 1.56 km/h). Each combination of these variables was replicated three times to measure the draft and torque for power requirement evaluation. and the broken-up soil height on the soil separation sieve mechanism. Four parameters λ(the ratio of vibration speed to forward velocity), p(the ratio of vibration acceleration to forward velocity), K(the ratio of vibration acceleration to gravitational acceleration), and T(the product of λ and K) were induced from three experimental variables: amplitude, frequency, and tractor speed. And the power requirement and soil separation ability were analyzed by regression. Though λ and K were known to be the representative parameters. T was the most moderate one to explain draft. torque. and soil separation in this study. It was estimated that the T equal to or greater than 2.4 was the minimum recommended value. Figure 18 would be useful fir the selection of amplitude. frequency, or operating tractor speed once any two variables are known.

• 보존과학회지
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• 제25권2호
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• pp.171-178
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• 2009

유구 이전의 안정성은 현재 개발되어 사용되고 있는 반수용성 우레탄 1 차 전사체와 2 차 최종 에폭시 생성물의 우수한 물성으로 볼 때, 박리제의 물성과 박리성에 의해 좌우된다. 본 연구에서는 계면활성제를 사용하지 않은 세 가지 형태의 자기분산형 박리제를 합성하여 이들이 나타내는 박리성과 물성, 박리 후의 상태에 대하여 연구하고자 하였다. 이 수용성 자기 분산형 에폭시의 그 간의 박리제에서 문제시 되었던 지속 기간을 5 시간에서 60 일 이상으로 개선하였으며, 30% 수용화 이상에서 안정한 박리성을 보이고 있고, 건조 전후의 표면 색도의 변화도 없었다. 계면활성화제를 사용한 박리제와 비슷한 결과로 박리압을 나타내어 15~50 kg/$cm^2$을 나타내고 있으며, 저점도의 폴리머 사용 시, 고형분의 함량을 높이더라도 백화 현상이 발생하지 않아 저점도형 박리제로 사용이 가능한 것으로 보인다.

• Nuclear Engineering and Technology
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• 제55권3호
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• pp.989-998
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• 2023

Under nuclear reactor severe accidents, the resuspension of radioactive aerosol may occur in the containment due to the disturbing airflow generated by hydrogen combustion, hydrogen explosion and containment depressurization resulting in the increase of radioactive source term in the containment. In this paper, for containment conditions, by considering the contact between particle and rough deposition surface, the distribution of the distance between two contact points of particle and deposition surface, rolling and lifting separation mechanism, resuspension model based on random contact with rough surface (RRCR) is established. Subsequently, the detailed torque and force analysis is carried out, which indicates that particles are more easily resuspended by rolling under low disturbing airflow velocity. The simulation result is compared with the experimental result and the prediction of different simulation methods, the RRCR model shows equivalent and better predictive ability, which can be applicable for simulation of aerosol resuspension in containment during severe accident.

• 청정기술
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• 제9권1호
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• pp.9-21
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• 2003

CFC-113, 1,1,1-TCE는 오존파괴물질로 선진국에서는 이미 사용이 전면 규제되고 있고 MC, TCE는 유해성 또는 발암성물질로 판명되어 일부사업장에서 제한적으로 사용되고 있다. 그러므로 세정성이 좋고 환경/안전성이 우수한 대체세정제를 개발하여 사용하거나 기존 개발된 세정제 중에서 우수한 세정제를 선정하여 사용하는 것이 필요한 실정이다. 대체세정제로는 수계세정제가 환경성과 경제적면에서 유망한 것으로 평가받고 있어 많은 사업장에서 사용될 전망이다. 본 연구에서는 환경친화적인 수계세정제를 개발하기 위하여 수계세정제의 주요성분인 여러 형태의 계면활성제를 선정하여 이들의 물성, 거품성, 오염물 종류에 따른 세정성, 유수분리성을 평가하여 비교하였다.

• 산업경영시스템학회지
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• 제4권5호
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• pp.15-26
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• 1981

While one characteristic of modern enterprises is that their forms are mostly stock company type profit organization the other characteristic is that such modern enterprises have mostly been managing under separation between capital and management. The term "Separation of ownership and Management" means that a company is controlled and managed not by its financier or investor but by the professional manager equipped with scientific management skill and knowledge. Nowadays, separation between capital and management could be adopted by advent of professional managers, and the enterprises are managed not exclusively by the interested group of stockholders but by the professional managers Professional managers can manage their enterprises in such a way as to guarantee to achieve sociality and public interests required in the modern enterprises. The purpose of this study is to formalize management ideology of enterprises in Daegu Area by means of comparative study on the degree of separation of ownership and management among enterprises in the United States, Japan and Daegu Area, thus to advise enterprising men of management idea-logy formalized. Findings from the comparative study are as follows 1. There are differences in staffing and financing between enterprises of the United States and those of Japan and Daegu Area. 2. Degree of Separation of ownership and management in Japan and Daegu Area is much less than that of the United States, and 3. The degree of separation of ownership and management is higher in open enterprises in Daegu Area. Accordingly. enterprises in Daegu Area should adopt up-to-data management theory and techniques in order to be developed themselves, and furthermore, to contribute to both the nation and the local community in economic development. In modern industrial society, the scale enterprise organization is growing very rapidly and the managerial circumstances are very much complicate and variable , thus the demand for the competent managers equipped with management knowledge and ability are high. The necessity of systematic and efficient managerial training is social demand needed urgently in modern industrial society. Therefore, it is necessary for the enterprising men in Daegu Area to establish cooperation system between university and industry in which they can participate voluntarily.luntarily.

• 항공우주시스템공학회지
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• 제12권5호
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• pp.69-75
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• 2018

본 논문에서는 전기 접속부 역할을 하는 포고핀을 활용한 극초소형 위성용 나일론선 절단방식 태양전지판 분리장치를 제안하였다. 제안된 분리장치는 종래 나일론선을 이용한 분리장치에 비해 높은 체결력 및 횡/종방향 동시구속이 가능하고, 체결작업이 용이하며, 또한 다수의 태양전지판의 동시분리가 가능한 장점을 갖는다. 또한 제안된 분리장치에 적용된 포고핀은 전력공급을 위한 전기 접속부 기능과 함께 전개 상태 스위치 및 태양전지판의 분리 스프링 역할이 동시에 가능하다. 본 논문에서는 제안된 포고핀 분리장치의 기능성 입증을 위해 체결횟수에 따른 분리 기능시험을 통해 기능성을 검증하였다.