• Nuclear Engineering and Technology
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• 제53권1호
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• pp.253-257
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• 2021

This work demonstrates the use of baromembrane method based on reverse osmosis (RO) process. The method is realized on mobile complex, which allows to concentrate and determine ultra-low activity of radionuclides in water cooling ponds of Russian nuclear fuel cycle enterprises. The existence level of radionuclide background creates difficult conditions for identification the contribution of liquid discharges enterprise, as standard monitoring methods have a very high detection level for radionuclides. Traditional methods for determining the background radionuclides concentrations require the selection of at least 500 liters (l) of water, followed by their evaporation to form a dry residue. This procedure with RO membranes requires at least 5 days. It is possible to reduce the time and energy spent on evaporation of hundreds of water liters by pre-concentrating radionuclides in a smaller sample volume with baromembrane method. This approach allows preliminary concentration of water samples from 500 l volume till 20 l volume during several hours. This approach is universal for the concentration of dissolved salts of any heavy metals, other organic compounds and allows the preparation of water countable samples in much shorter time compared to the traditional evaporation method.

• 대한기계학회논문집A
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• 제26권5호
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• pp.813-821
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• 2002

Glass fiber reinforced PET matrix composite was manufactured by rapid press consolidation technique as functions of temperature, pressure and time in pre-heating, consolidation and solidification stages. The optimal manufacturing conditions for this composite were discussed based on the void content, tensile, interlaminar shear and impact properties. In addition, the levels of crystallinity with various manufacturing conditions were measured using differential scanning calorimetry to investigate the mechanical properties of this composite material as a function of crystallinity. Among many processing parameters, the mold temperature and the cooling rate after forming were found to be the most critical factors in determining the level of crystallinity and mechanical properties. The level of crystallinity affects the tensile properties to some degree. However, impact properties are affected much more. It also affects the degree of ductility, which determines the impact energy of this material.

• Journal of Chest Surgery
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• 제24권7호
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• pp.669-673
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• 1991

Fructose-l, 6-diphosphate as an additive to cold crystalloid cardioplegia [St. Thomas sol.] was studied prospectively in 60 patients undergoing open heart surgery from January 1, 1991, to June 30, 1991. Thirty patients received cardioplegia with FDP[group I ] and 30 patients received cardioplegia without FDP [group II ]. There were no differences between two groups pre-operatively with regard to age, heart disease, cross-clamp time, cardiac enzymes, or hemodynamic measurements [p>0.05]. Cardiopulmonary bypass was established using ascending aorta and vena cava cannulation employing moderate systemic hypothermia [30oC nasopharyngeal temperature] and hemodilution All patients received cardioplegia through the aortic root at aortic root pressure of 80mm Hg. The composition of the cardioplegic solution and its delivery were identical in both groups except for the addition of FDP[1.5 mg/mL] in group I. The cardioplegic infusate consisted of St. Thomas Hospital solution. The initial dose was infused through the aortic root. Topical myocardial cooling with saline slush was employed in all patients. Recorded operative data were cardiopulmonary bypass and cross-clamp times, amount of cardioplegic infusate. Blood samples for assessment of lactate dehydrogenase [LDH], creatine kinase [CK] and transaminases [GOT, GPT] were obtained before and at 1,2,3,7th postoperative period. Better myocardial protection effect was noted in group I than group II with respect to the % change of cardiac enzymes, although the differences were not significant. We conclude that FDP is a safe additive to crystalloid cardioplegia and may be beneficial in open heart surgery patients.

• 천문학논총
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• 제23권1호
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• pp.1-12
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• 2008

Understanding of the basic characteristics of an astronomical instrument is a prerequisite to obtaining reliable data from the instrument. We have analyzed more than 1,000 calibration images from the Fairchild 486 CCD (hereafter the Maidanak 4k CCD system) attached to the AZT-22 1.5m telescope at Maidanak Astronomical Observatory in Uzbekistan. The Maidanak 4k CCD system supports three readout modes through 1, 2, or 4 amplifiers. In most cases observers use 4-amplifier readout mode to save time. We have tested the stability and seasonal variation of zero levels and confirm that two quadrants of the images (Amp 1 & 2) show no appreciable seasonal variation. but the other two quadrants (Amp 3 & Amp 4) show an evident seasonal variation in the bias level. The Cryo Tiger, the cooling system used at the Maidanak 4k CCD system, maintains the CCD temperature at -108'E, and effectively suppresses the dark electrons. The mean value versus the variance plot of the flat images does not show the expected relation for an ideal Poisson noise distribution and this is attributed to the large variation in quantum efficiency between different pixels. In addition, we confirm that there is no appreciable difference in gain between readout amplifiers, but there is a large variation in quantum efficiency across CCD chip especially in U. Due to the finite length of shutter opening and closing time, the effective exposure time varies across the science images. We introduce two parameters to quantify the effect of this uneven illumination and present a method to remove these effects. We also present a method to remove the interference patterns appearing in the images obtained with longer wavelength filters and investigate the spatial variation of the point spread function.

• 한국식품조리과학회지
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• 제2권2호
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• pp.21-31
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• 1986

Here is a research on hospital foodservice system, when korea traditional food of pyeon yuk and bin dae deok were used by ready-prepared foodservice system, it was estimated the preservations of microbiological quality and sensory quality. All data collection was replicated three times. The results were as following; 1. In time and temperature data, two menu items were needed internal temperature below $7^{\circ}C$ in a cooling stage, and in the case of cook/chill storage, the days were shortened within weeks, and the holding time must be possiblely minimized. Finally foods were served sanitary. 2. In view of microbiological safety, in the case of cook/chill storage as $0{\sim}4^{\circ}C$ the days must be shortened within 2 weeks and its was possible to store until 6 weeks in $-20{\sim}-23.3^{\circ}C$. So to preserve pre-cooked food longly, it was effective to freeze them quickly by using vacuum package and to reheat them by a microwave oven before serving and to serve lastly in microbiological quality. 3. Hospital ready-prepared foodservice system with food storage in plastic bags, biochemical test of C. Perfingens C. botulinum and Salmonella were not detected. 4. By using of a microwave oven, it had effects of thawing, reheating and sterilizing of chilled and frozen foods in a short time. 5. Sensory evaluations were made by a 10-member panel using five scoring tests. Because sensory of quality was lowered in the case of chilled storage, it was possible to serve foods within 2 weeks. Texture and aroma were preserved by cook/frozen system and usually there was no significance from 4 weeks until 6 weeks, but considering of the objects, it was good to store until 4 weeks in sensory quality.

• 감성과학
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• 제21권2호
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• pp.137-144
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• 2018

본 연구에서는 가변 통기성 스마트 의류의 제작을 위해 필요한 형상기억합금 액추에이터의 작동 조건을 파악하였다. 의복의 개방, 폐쇄와 같은 양방향 작동 시 형태 변형 시에만 전력을 소모하는 저전력 소모 액추에이터 개발을 위해 복수 채널의 일방향 형상기억합금을 이용하여 스위치로 작동되는 액추에이터를 설계하였으며 가장 효율적으로 작동할 수 있는 와이어의 직경과 전압인가 단위시간을 도출하였다. 선행연구 결과 도출된 양방향 작동이 가능한 일방향 형상기억합금의 직경 범위 내에서 Arduino 스위치를 제작하여 3.7V 전압인가 시 변화량을 분석한 결과 $0.4{\Phi}$의 액추에이터가 가장 적합한 것으로 나타났다. $0.4{\Phi}$ 형상기억합금와이어를 사용한 양방향작동 액추에이터의 개방, 폐쇄에 필요한 최적전압인가 시간을 도출하기 위해 액추에이터의 최대개방, 최소폐쇄 도달 전압인가 시간으로부터 50ms씩 감소, 증가 시키며 냉각 후 액추에이터의 내경을 비교하는 방식으로 측정한 결과 개방 동작에 필요한 최적 전압인가 단위시간은 4,100ms로 나타났다. 각 채널간의 발열에 의한 간섭을 최소화하기 위한 양방향간 작동 시 필요 딜레이 분석을 위해 상온에서 형상기억합금에 최적 전압입가 시간인 4.1초 동안 전원을 공급하고 가열 후 냉각까지의 과정을 열화상카메라로 촬영하여 형상기억합금 와이의 온도가 냉각시의 상변태온 이하로 하강하는 시점을 파악한 결과, 액추에이터의 양방향간 작동 딜레이는 1.8초 이상이 확보되어야 함을 파악할 수 있었다.

• The Korean Journal of Pain
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• 제13권2호
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• pp.156-163
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• 2000

Background: Peripheral nerve injury sometimes leads to chronic neuropathic pain such as causalgia. A subset of patients with causalgia have a sympathetically maintained pain which is often evoked by cooling stimuli. However, our knowledge on adrenergic receptor types responsible for cold-evoked pain that is sympathetically dependent is lacking. The present study was conducted to investigate subtypes of adrenoceptors involved in mediating cold-evoked pain that developed following peripheral nerve injury. Methods: Neuropathic surgery was performed by a unilateral ligation of L5 and L6 spinal nerves of rats. Behavioral sign of cold-evoked pain was examined for 5 min by measuring cumulative duration of time that the rat lifted its foot off a metal plate held at cold temperature ($5^{\circ}C$). Whether cold-evoked pain behavior was affected by antagonists of various subtypes of adrenoceptors, which were administered intraperitoneally before and after the ligation, was investigated. Results: After ligation, duration of foot lifting on the ligated side at cold temperature increased as compared to the pre-operative period. This increase maintained for the entire 40-day test period. Pretreatment with alpha-antagonist phentolamine produced a suppression of cold-evoked pain behavior that was not affected by beta-antagonist propranolol pretreatment. Prazosin, alpha-1 antagonist, suppressed cold- evoked pain behavior when treated either before or after nerve ligation. On the other hand, alpha-2 antagonist yohimbine was without effect on cold-evoked pain behavior whether it was treated before or after the ligation. Conclusions: The results suggest that peripheral nerve injury develops cold-evoked pain that is sympathetically dependent, and that alpha-1 adrenoreceptor plays a critical role for the generation of this type of pain in its initiation as well as maintenance.

• 한국지반공학회논문집
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• 제29권8호
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• pp.65-73
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• 2013

지중 열교환 시스템은 지속적인 에너지 효율의 개선으로 공간 냉난방을 위한 친환경적 에너지 기술로 주목받고 있다. 지중에 매설된 파이프는 내부 유체 순환을 통하여 인접한 지반과 열적 상호작용으로부터 직접적인 열에너지 교환을 수행한다. 하지만, 파이프의 수치모델링에서 열-수리가 연관된 난류해석과 파이프의 긴 세장비에 의한 메쉬사이즈의 부적합성은 열교환 시스템의 적절한 수치해석을 어렵게 하고 있다. 본 논문에서는 파이프 내부 유체흐름에 대한 에너지 보존의 법칙을 적용하여 지배방정식을 유도하였으며, Galerkin수식화와 시간적분을 통하여 열-수리 연동일차원 파이프 요소를 개발하였다. 그리고 제안된 파이프 요소를 기 개발된 다공질 재료를 위한 열-수리-역학(Thermo-Hydro-Mechanical) 해석을 위한 유한요소 프로그램과 결합하였다. 개발된 요소를 이용한 수치해석 결과는 열응답 시험(Thermal Response Test) 결과로부터 주위지반의 유효 열전도도를 평가하기 위하여 사용하는 선형 열원 모델이 인접 파이프간의 열적상호작용과 파이프의 단부효과에 의하여 지반의 열전도도를 과다 평가하는 것으로 보여주었다. 따라서 열응답 시험 해석 결과에 대한 역해석을 적용하여 최적의 수렴성을 보여주는 변환행렬을 제시하였다.

• 한국농촌생활과학회지
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• 제5권1호
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• pp.1-8
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• 1994

온랭 열 자극에 대하여 인체의 말초 혈류량과 심박수가 어떻게 반응하는가를 관찰하기 위하여 건강한 성인 여자 4명을 피험자로 실험군과 비교군으로 나누어 실험을 실시하였다. 실험군은 온랭열 자극의 단기 훈련을 12회 실시하고 비교군은 실험군의 초기와 말기 2회 실시하여 얻은 결과를 비교ㆍ검토하여 다음과 같은 결과를 얻었다. $\circled1$ 실험군에서의 손가락 혈류량의 초기 반응은 훈련 후에 민감해졌다. $\circled2$ 심박수는 냉수 노출시보다 온수 노출시 증가하였다. $\circled3$ 실험군과 비교군간에는 혈류량의 변화 형태와 심박수에 차이가 있었다. 이상에서 E-군과 C-군의 혈류량과 심박수에서 차이를 나타낸 것은 단기 훈련 효과에 의한 것으로 추정된다.

• International Journal of Computer Science & Network Security
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• 제21권3호
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• pp.245-256
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• 2021

Poor logistical infrastructure and agri-food supply chain management leads to significant food waste in logistic system. The concept of the sustainable value added agri-food chains requires defined approach to the analysis of the existing situation, possible improving strategies and also assessment of these changes impact on further development. The purpose of research is to provide scientific substantiation of theoretical and methodological principles and develop practical recommendations for the improvement of the agri-food logistics distribution system. A case study methodology is used in this article. The research framework is based on 4 steps: Value Stream Mapping (VSM), Gap and Process Analysis, Validation and Improvement Areas Definition and Imitation Modelling. This paper presents the appropriateness of LEAN logistics tools using, in particular, Value Stream Mapping (VSM) for minimizing logistic losses and Simulation Modeling of possible logistics distribution system improvement results. The algorithm of VSM analysis of the agri-food supply chain, which involves its optimization by implementing the principles of sustainable development at each stage, is proposed. The methodical approach to the analysis of possible ways for optimizing the operation of the logistics system of the agri-food distribution is developed. It involves the application of Value Stream Mapping, i.e. designing of stream maps of the creation of the added value in the agri-food supply chain for the current and future state based on the minimization of logistic losses. Simulation modeling of the investment project on time optimization in the agri-food supply chain and economic effect of proposed improvements in logistics product distribution system functioning at the level of the investigated agricultural enterprise has been determined. Improvement of logistics planning and coordination of operations in the supply chain and the innovative pre-cooling system proposed to be introduced have a 3-year payback period and almost 75-80% probability. Based on the conducted VSM analysis of losses in the agri-food supply chain, there have been determined the main points, where it is advisable to conduct optimization changes for the achievement of positive results and the significant economic effect from the proposed measures has been confirmed. In further studies, it is recommended to focus on identifying the synergistic effect of the agri-food supply chain optimization on the basis of sustainable development.