• 제목/요약/키워드: Critical period

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인터벤션 시술 시 환자의 선량감소를 위한 3D 프린팅 재료의 적용성 평가 (Feasibility of the 3D Printing Materials for Radiation Dose Reduction in Interventional Radiology)

  • 조용인
    • 대한방사선기술학회지:방사선기술과학
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    • 제43권3호
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    • pp.169-176
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    • 2020
  • Interventional radiology is performed under real-time fluoroscopy, and patients are exposed to a wide range of exposures for a long period of time depending on the examination and procedure. However, studies on radiation protection for patients during an intervention are insufficient. This study aims to evaluate the doses exposed during the intervention and the applicability of 3D printing materials. The organ dose for each intervention site was evaluated using a monte carlo simulatio. Also, the dose reduction effect of the critical organs was calculated when using a shielding device using 3D printing materials. As a result, the organ dose distribution for each intervention site showed a lower dose distribution for organs located far from the x-ray tube. It was analyzed that the influence of scattered rays was higher in the superficial organs of the back of the human body where x-rays were incident. The dose reduction effect on the critical organ using the 3D printing shield showed the highest testis among the gonads, and in the case of other organs, the dose reduction effect gradually decreased in the order of the eye, thyroid, breast, and ovary. Accordingly, it is judged that the 3D printed shield will be sufficiently usable as a shielding device for the radiation protection of critical organs.

이산요소법을 이용한 회전체의 크기에 따른 Washboarding 현상에 대한 영향 분석 (Effects on the Washboarding Phenomenon Based on the Size of the Rotating Body Using a Discrete Element Method)

  • 이승준;박준영
    • 한국기계가공학회지
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    • 제20권8호
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    • pp.25-32
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    • 2021
  • Washboarding is a crucial problem occurring on unpaved roads. This phenomenon involves the formation of ripples on the surface of the unpaved road and causes a critical problem to vehicles and riders. The phenomenon is affected by several parameters, but we focused on the velocity and the size of the rotating body. In the precedent research, we observed that a critical velocity existed for the occurrence of the phenomenon, and the phenomenon's grade was related to the velocity. Therefore, this study, using a discrete element method, aimed to analyze the relation between the velocity and the size of the rotating body for the occurrence of the phenomenon and perform a fast Fourier transform (FFT) analysis to determine the correlation between the phenomenon and the period. The study observed that the critical velocity could vary from the velocity and the size of the rotating body, and there was a certain range of frequency for the occurrence of the Washboarding phenomenon.

일제말기 근대비판 담론의 시간성 연구: 세계사·전통·비상시 (A Study of Temporality of a Critical Discourse on the Modern in the Late Japanese Colonial Period)

  • 고봉준
    • 비교문화연구
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    • 제23권
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    • pp.33-55
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    • 2011
  • In the late Japanese colonial period, from the Sino-Japanese War until the Pacific War, critical discourses on the modern were prevalent in Japan and the Joseon. Despite the absence of a consensus about the specific definition of the modern, most thinkers agreed that the modern was something to be overcome. While some regarded naturalism and capitalism of the West as the essence of the modern, some others named scientism and humanism as the nature of the western modernity. Additionally, some criticized the temporal concept of historicism and brought new meanings of 'tradition' into relief, and some others advocated overcoming 'the West inherent in us'. This study is to consider the temporality of the theory of overcoming the modern focusing on the following three notions-world history, tradition, and emergency-, and examines the antinomy of them. The first notion to consider is 'world history'. The theorists of overcoming the modern, including the Kyoto school, discarded the progressive ideology that had led the Western modern history, and instead introduced 'world history' as a new notion. Although this resulted from the imperialistic embracement of the theories of Ranke, a major positivist historian from Germany, it contained antinomy of remaining in 'history' which was the modern temporal view. The second notion is 'tradition'. While the critical mind of 'world history' brought 'time of world' into question in the context of temporal realization, the notion of 'tradition' was to understand 'time of history' itself as the modern and overcome it. The critical mind of the notion involves the attempts to criticize regarding history as a 'progressive' process and to discover tradition as 'the present past' or 'the eternal present'. However, it also contained antinomy; the 'tradition' here was a notion that was created in the modern times, not passed down from ancient times. The third notion to consider is 'emergency', which was a method to define the present time as a transition period toward a new era, relating to states of war. However, the theorists of overcoming the modern did not regard 'emergency' as a particular time that strayed from normal states, instead they thought is as 'a regularized exceptional state', namely 'a state in which exceptions have become regulations'. However, the notion also contained antinomy since the word 'emergency' connotes abnormality.

Is the Critical Period Hypothesis Relevant in the EFL Situation\ulcorner

  • Ahn, Soo-Woong
    • 한국영어학회지:영어학
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    • 제1권4호
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    • pp.587-608
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    • 2001
  • When teaching English in elementary schools was introduced in Korea in 1997, the theoretical basis was the critical period hypothesis (CPH). The object of this study was to test whether the Korean situation satisfies the conditions for the CPH such as the amount of English input and needs. As a test for this, English input and needs were compared in Korea, the U.S.A. and Singapore. The items for English input were on a continuum of primary to secondary sources and the items for English needs were on a continuum of immediate to future needs. The 0-5 scale was used. The result showed that the total means of English input were 4.87, 4.62, and 1.05 for children in the U.S.A., Singapore and Korea respectively. The total means of English needs were 4.32, 3.81, and 1.52 for children in the U.S.A., Singapore and Korea respectively. These figures show that Korean children's levels of both input and needs were from “almost none” to “little,” while those of children in the U.S.A. and Singapore were from “much” to “very much.” This shows that teaching English in Korea presently is far from meeting the conditions that are expected by the CPH. As an alternative to explain what happens cognitively to Korean children, this paper suggests the automatization and proceduralization processes.

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초급성기 중증 뇌 손상 환자의 영양 상태 변화양상과 인공영양 전·후의 영양 상태에 대한 비교 (Changing Pattern and Comparison of Nutritional States before and after Nasogastric Tube Feeding for the Severe Brain Injury Patients in Critical Period)

  • 박종숙;오현수;서화숙;서연옥
    • 성인간호학회지
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    • 제20권1호
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    • pp.44-54
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    • 2008
  • Purpose: The purpose of the study were to examine the nutritional status of severe brain injury adult patients in critical period, and to compare the nutritional states before and after tube feeding. Methods: Data from 19 patients admitted to the SICU in a university hospital due to severe brain injury were analyzed. Nutritional states were measured by anthropometric and blood biochemical indicators. Results: MAC and MAMC were significantly decreased only at 7 days after admission compared with those on the day of admission. TSF was significantly decreased from 7 days to 14 days after admission. Fat rate was significantly decreased from 3 days to 14 days after admission. Hb was significantly decreased only at 3 days after admission. Albumin was significantly decreased from 3 days to 14 days after admission. However, lymphocyte was significantly increased at 14 days after admission. TSF and Albumin became significantly worse even after initiating tube feeding. Conclusions: Nutritional status of severe brain injury patients in SICU became worse after admission whichever indicators were adopted to evaluate nutritional status, anthropometric or blood biochemical indicators, and became worse even after initiating tube feeding.

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마이크로파 가열에 의한 도금슬러지 건조특성 (Drying Characteristics of Plating Sludge by Microwave)

  • 문경환;손종렬;김덕찬
    • 환경위생공학
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    • 제13권1호
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    • pp.9-15
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    • 1998
  • Microwave heating and drying processes have been well established in various industrial applications. Feasibilities of successful application of microwave drying to many material have been shown on the laboratory or pilot-plant scale. The microwave drying behavior of plating sludge are considered in this paper. The plating sludge containing 70%, 80% and 90% water exposed to microwave power at 2,450 MHz, 700W. An experimental microwave drying apparatus was designed and constructed to monitor weight loss during drying. By studying the drying characteristic curve, the moisture in sludge was almost classified into two categories : free moisture and intestinal moisture. And the critical moisture contents at which the drying rate ceases to be constant were from 10.1 to 10.5%. A simple drying model is proposed which may be used to describe drying behavior of plating sludge. The constant rate and the falling rate periods in microwave drying were addressed separately. From the eqation of constant rate period the drying rate constants decreased exponentially with increasing depth. Microwave heating compared with conventional heating offered higher heating rates from 9 to 16 times. Therefore, microwave drying process can be effective in removing moisture from plating sludge.

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간호사의 손위생 지식, 인식 및 자가 보고 손위생 수행률에 대한 조사 연구 (A Survey of Nurses' Hand Hygiene Knowledge, Perception and Hand Hygiene Performance Rate)

  • 차경숙;고지운;한시현;정경희
    • 중환자간호학회지
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    • 제11권1호
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    • pp.101-109
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    • 2018
  • Purpose : The purpose of this study was to identify the knowledge, perception and hand hygiene performance rate of hospital nurses and to identify any correlation between them. Method : Data were collected from 205 nurses working in a university hospital in Chungcheong-do. A self-report survey method was utilized. Participants completed the hand hygiene knowledge questionnaire. Results : The average knowledge of hand hygiene was 11.76 (out of 18 points), and the average perception of hand hygiene was 35.55 (out of 96). The hand hygiene performance rate was 85.62%. Knowledge of hand hygiene showed significant differences according to age (F = 75.821, p < .001), gender (t = 25.049, p < .001) and working period (F = 24.843, p < .001). The most important explanatory factor in hand hygiene performance was hand hygiene perception (${\beta}=.26$), followed by working period (${\beta}=.14$). These variables accounted for 10.0% of subjects' hand hygiene performance. Conclusion : The results of this study suggest that continuous and effective education is needed to strengthen knowledge and perception of the importance of hand hygiene practice for nurses to prevent healthcare-associated infections.

심장판막 수술환자의 회복기간에 따른 증상클러스터와 삶의 질 변화 (Symptom Clusters and Quality of Life Changes according to Recovery Period of Patients with Heart Valve Surgery)

  • 황순정;강정희
    • 중환자간호학회지
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    • 제12권1호
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    • pp.1-12
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    • 2019
  • Purpose : It is widely accepted that addressing multiple symptoms together is the preferred approach in assessment and intervention and results in reduced negative patient outcomes. Yet, there are few studies examining symptom clusters and their impacts on quality of life longitudinally in patients after heart valve surgery. Methods: A total of 101 patients were recruited from a tertiary hospital and were administered questionnaires (at 3, 6, and 10 weeks after the surgery) assessing participants' characteristics, cardiac symptoms, and quality of life. Factor analysis was used to identify symptom clusters. Hierarchical multiple linear regression was used to predict quality of life. Results: Participants were predominantly 70-years old or more with a mean age of 64.34. The two symptom clusters at 3 weeks after the surgery with education, gender, and occupation accounted for 76.3% of variance in quality of life. Conclusion: Symptom clusters containing various physical and psychological symptoms in patients after the surgery affected quality of life, and the relationship was significant at 3 weeks after the surgery. Because symptom clusters were identified in all three recovery periods, nurses need to acknowledge these clusters, rather than each symptom separately, and to utilize these in providing care and education and in promoting quality of life in these patients.

Optimum design of viscous dampers to prevent pounding of adjacent structures

  • Karabork, Turan;Aydin, Ersin
    • Earthquakes and Structures
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    • 제16권4호
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    • pp.437-453
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    • 2019
  • This study investigates a new optimal placement method for viscous dampers between structures in order to prevent pounding of adjacent structures with different dynamic characteristics under earthquake effects. A relative displacement spectrum is developed in two single degree of freedom system to reveal the critical period ratios for the most risky scenario of collision using El Centro earthquake record (NS). Three different types of viscous damper design, which are classical, stair and X-diagonal model, are considered to prevent pounding on two adjacent building models. The objective function is minimized under the upper and lower limits of the damping coefficient of the damper and a target modal damping ratio. A new algorithm including time history analyses and numerical optimization methods is proposed to find the optimal dampers placement. The proposed design method is tested on two 12-storey adjacent building models. The effects of the type of damper placement on structural models, the critical period ratios of adjacent structures, the permissible relative displacement limit, the mode behavior and the upper limit of damper are investigated in detail. The results of the analyzes show that the proposed method can be used as an effective means of finding the optimum amount and location of the dampers and eliminating the risk of pounding.

제왕절개술 환자를 위한 Critical Pathway 개발 (Development of the Critical Pathway for Cesarean Section Patient)

  • 정경희;장금성
    • 한국간호교육학회지
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    • 제4권1호
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    • pp.66-80
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    • 1998
  • With the opening of healthcare market, the health care environment in Korea is anticipating a drastic change. In this Internationally open market environment, it is necessary to introduce a systematic health care plan and DRG system which offer qualitative medical services as well as reduced cost. Purpose of this study is to develop and test the critical pathway for Cesarean section patient in the way to be possible the integrated inpatient management. It was adopted the process of six phases to develop the critical pathway as the theoretical framework implemented by Johns Hopkins Hospital, Maryland, U.S.A. In the first phase, make a selection of diagnosis/procedures to develop. In the second phase, organize a development team consisted of eight expertises working in maternity nursing area. In the third phase, analyze the overall medical service offered to patient through review medical records and decided the service content and the implementation period for the Cesarean section patient. In the forth phase, make out a preliminary critical pathway after verification of expert group on content validity. In the fifth phase, validity operate to ten Cesarean section patients to test implementation in practice by using the preliminary critical pathway, In the sixth phase, defined the final critical pathway. The result of this study was as follows. 1. There were classified 8 categories as monitoring/assesment, treatment, medication, activity, diet, test, consult, education/discharge plan for vertical axis and showed hospital stayed from admission to discharge for horizontal axis of critical pathway through analysis 68 Cesarean section patients medical records. 2. After critical review 68 medical records to make out a preliminary critical pathway, hospital stays for horizontal axis were showed 6 days, mean hospital stays were 7.5 days, 2.1 days were to be taken operation after admission and 4.2 days were stayed until discharge after operation. 3. After making out a questionare in 90 items of a medical service content of eight categories and verifying the content validity of expertises, the 85 items of the preliminary critical pathway were selected by expertises agreement over 88% and modified or deleted 5 items showing agreement below 75%. 4. After verifying a validity to 10 patients for 4 weeks, hospital stays were 5.9 days. There were deleted 1 item and modified or supplemented the 9 items of the 10 items.

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