• 산업기술연구
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• 제22권A호
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• pp.3-8
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• 2002

In this study, extremely low cycle fatigue tests were carried out under push-pull loading conditions using graphite cast iron (GCD). In order to clarify the fatigue fracture mechanism of GCD in an extremely low cycle fatigue regime successive observations of internal fatigue damage were performed. The results obtained are as follows. (1) The process of extremely low cycle fatigue can be classified into three stages which are composed of the generation, growth and coalescence of microvoids inside materials. (2) In an extremely low cycle fatigue regime, microvoids originate from debonding of graphite-matrix interface.

• 대한간호학회지
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• 제4권1호
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• pp.135-150
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• 1974

A study on the importance of fifty selected nursing activities that classified into four categories of patient care (physical care. psychological aspects of care, observing, reporting and implementing medical care, care for admission and discharge) was carried out from september 25 to October 10, 1973 toward 300 hospitalized patients and 300 professional nurses in four university hospitals in Seoul. The results were obtained as follows The importance score in order on four categories of nursing activities were seen as follows : 1. in physical care activities patients noted; moderately important 35.0% extremely important 20.5% very important 19.3% slightly important 18.6% not at all important 6.6% nurses noted: moderately important 41.5% very important 29.4% extremely important 23.5% slightly important 6.2% not at all important 3.4% 2. in activities involving psychological aspects of care patients noted: moderately important 33.4% very important 25.2% extremely important 23.2% slightly important 14.3% not at all important 3.9% nurses noted: moderately important 42.3% very important 34.8% extremely important 16.0% slightly important 6.2% not at all important 0.7% 3. in activities involving observing, reporting, and implementing medical care patients noted ; extremely important 35.9% moderately important 28.0% very important 26.0% slightly important 8.4% not at all important 1.7% nurses noted : extremely important 38.1% very important 31.8% moderately important 26.1% slightly important 3.6% not at all important 0.4% 4. in activities preparing for admission and discharge patients noted: moderately important 35.8% extremely important 24.5% very important 23.5% extremely important 12.5% not at all important 3.7% nurses noted: moderately important 47.6% very important 33.1% extremely important 12.5% slightly important 6.0% not at all important 0.8%

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제17권2호
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• pp.145-150
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• 2010

In this paper, we introduce the concepts of faintly ${\gamma}$-continuity and extremely ${\gamma}$-closed graph. And we study characterizations of such functions and relationships between faintly ${\gamma}$-continuity and extremely ${\gamma}$-closed graph.

• 한국농림기상학회지
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• 제5권3호
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• pp.191-199
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• 2003

Optimum transplanting time for extremely early rice cultivation as an after-crop of fruit and vegetables under greenhouse conditions in the southern area was determined. Rice was transplanted on March 10, March 20, March 30, April 10 and April 20 far three years from 1998 to 2000. Meteorological computations for rice production were high for heading between early May and early July, but they were too low for heading between late July and early August. Especially the expected yield predicted with 35,000 spikelets, the average spikelets per $m^2$ for extremely early transplanting. Computation for heading between late July and early August was low by 106 kg/10a compared with that yield at heading during the same period in the field. As the transplanting date in extremely early rice cultivation was earlier) rice growth at early stages was more retarded by low temperature. Rice growth at heading stage recovered with high temperature, showing less difference for the transplanting date. Abnormal tillers occurred by 15.5∼22.2%. The contribution of 1,000 grain weight${\times}$ripened grain ratio to yield of the extremely early rice cultivation in the greenhouse was 50.6%, indicating 16% hi일or than the degree of panicle per $m^2$ on yield. The estimated optimum transplanting time on the basis of yield for the extremely early greenhouse rice cultivation ranged from March 19 to April 28, and the estimated critical transplanting date on the basis of accumulated effective temperature was March 12. Rice reduced the amount of NO$_3$-N by 97.1% and EC by 90.5% in greenhouse soil with continuous fruit/vegetables fer more than a 10-year period, and completely removed the root-knot nematodes.

• 한국지역지리학회지
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• 제2권2호
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• pp.103-111
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• 1996

본 연구는 지표상의 기상 요소의 분포 특성이 이압계(氣壓系)뿐만 아니라 기압계를 지배하는 상충대기의 상층대기의 환류(還流)의 특성과도 밀접한 관계가 있음을 기준하여, 우리나라에 있어서 지난 30년간($1965{\sim}1994$) 28개 관측지점을 대상으로 동계 기온을 표준편차(標準偏差)에 의해 분류하였으며, 여기서 나타난 이상한(異常寒) 난월(暖月) 중 대표적인 1992년(이상난한동월(異常暖寒冬月), EH)과 1984년(이상한동월(異常寒冬月), EL)의 1월에 있어 500hPa면 고도 특성 및 몇 가지의 분석을 통하여 한 난동월의 특징을 살펴보았다. 난동월(暖冬月)에서는 강수량이 많았다. 우리나라의 경우 500hPa면은 난동월(暖冬月)에는 trough를 한동월(寒冬月)에는 남북유형(南北類型)유형을 나타내고 있다. 순환의 특징에서 우리나라 부근의 500hPa면 고도는 난동월년이 1984년에 비해 높았고, 동서지수에 있어서도 난동월이 높았다. 이외에도 환류형과 환류파수형에서는 난동월이 M형의 3파수, 1984년이 5형의 3파수(波數)로 나타나 단지 파수형(波數型)만으로는 한(寒) 난동월(暖冬月)을 구분하기가 어려운 것으로 밝혀지고 있다. 지상 기압에 있어서는 한동월이 난동월에 비해 서고동저(西高東底)의 기압배치가 강하게 나타나고 있다. 향후 동계 전월에 관해 850hPa면의 분석 등을 추가한 좀 더 포괄적인 연구를 하고자 한다.

• Journal of Astronomy and Space Sciences
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• 제36권3호
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• pp.213-223
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• 2019

This paper analyzes delta-Vs to maintain an extremely low altitude on the Moon and investigates the possibilities of performing a CubeSat mission. To formulate the station-keeping (SK) problem at an extremely low altitude, current work has utilized real-flight performance proven software, the Systems Tool Kit Astrogator by Analytical Graphics Inc. With a high-fidelity force model, properties of SK maneuver delta-Vs to maintain an extremely low altitude are successfully derived with respect to different sets of reference orbits; of different altitudes as well as deadband limits. The effect of the degree and order selection of lunar gravitational harmonics on the overall SK maneuver strategy is also analyzed. Based on the derived SK maneuver delta-V costs, the possibilities of performing a CubeSat mission are analyzed with the expected mission lifetime by applying the current flight-proven miniaturized propulsion system performances. Moreover, the lunar surface coverage as well as the orbital characteristics of a candidate reference orbit are discussed. As a result, it is concluded that an approximately 15-kg class CubeSat could maintain an orbit (30-50 km reference altitude having ${\pm}10km$ deadband limits) around the Moon for 1-6 months and provide almost full coverage of the lunar surface.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2000년도 가을 학술발표회논문집
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• pp.174-181
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• 2000

A brief review of previous studies on the behaviour of concrete at extremely low temperature is presented in this paper. In addition, to describe temperature dependent behaviour of concrete, simple piecewise linear stress-strain relation is introduced. The proposed curve shows good agreement with experimental stress-strain curves at various temperature conditions. Moreover, numerical analyses for two PC beams are conducted to verify the influence of extremely low temperature to the structural behaviour.

• Neonatal Medicine
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• 제25권1호
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• pp.7-15
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• 2018

We need to understand the outcomes into adulthood for survivors born either extremely low birthweight (ELBW; <1,000 g) or extremely preterm (EP; <28 weeks' gestational age), particularly their blood pressure and cardiovascular metabolic status,respiratory function, growth, psychological and mental health performance, and functional outcomes. Blood pressure is higher in late adolescence and early adulthood in ELBW/EP survivors compared with controls. In some studies, expreterm survivors have higher insulin and blood lipid concentrations than controls, which may also increase their risk for later cardiovascular disease. ELBW/EP survivors have more expiratory airflow obstruction than do controls. Those who had bronchopulmonary dysplasia (BPD) in the newborn period have even worse lung function than those who did not have BPD. As a group, they are unlikely to achieve their full lung growth potential, which means that more of them are likely to develop chronic obstructive airway disease in later life. Although they are smaller than term born controls, their weight gradually rises and ultimately reaches a mean z-score close to zero in late adolescence, and they ultimately attain a height z-score close to their mid-parental height z-score. On average, ex-preterm survivors have intelligence quotient (IQ) scores and performance on tests of academic achievement approximately 2/3 SD lower than do controls, and they also perform less well on tests of attention and executive function. They have similar high rates of anxiety and depression symptoms in late adolescence as do controls. They are, however, over-represented in population registries for rarer disorders such as schizophrenia and Autism Spectrum Disorder. In cohort studies, ex-preterm survivors mostly report good quality of life and participation in daily activities, and they report good levels of self-esteem. In population studies, they require higher levels of economic assistance, such as disability pensions, they do not achieve education levels as high as controls, fewer are married, and their rates of reproduction are lower, at least in early adulthood. Survivors born ELBW/EP will present more and more to health carers in adulthood, as they survive in larger numbers.

• 보건행정학회지
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• 제25권4호
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• pp.277-284
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• 2015

Background: This study investigates the relationship of socioeconomic status with adverse birth outcomes (low birth weight, preterm birth) and the relationship of socioeconomic status with infant mortality, using the birth cohort in Korea, 1995-2010. Methods: 8,648,035 births from National Statistics Offics, 1995-2010 were studied with respect to social variation in adverse birth outcomes and infant mortality in Korea. The effect of social inequality was examined against adverse birth outcomes and infant mortality using multivariate logistic regression after controlling for other covariates. Results: Social inequality were observed in adverse birth outcomes: low birth weight (LBW, 1,500-2,499 g), very LBW (1,000-1,499 g), and extremely LBW (500-999 g) as well as moderately preterm birth (PTB, 33-36 weeks), very PTB (28-32 weeks), extremely PTB (22-27 weeks), and infant mortality. The effect of social inequality was higher among moderately LBW (1,500-2,499 g) and PTB (33-36 weeks) than very or extremely LBW and PTB. Conclusion: The social inequality in adverse birth outcomes (low birth weight and preterm) and infant mortality existed and increased in Korea from 1995 to 2010. The effect of maternal education on adverse birth outcomes as well as infant mortality was apparent in the study results. Especially, social inequailiy in infant mortality was greater among the sub-normal births (low birth weight [1,500-2,499 g] or preterm birth [33-36 weeks]), which suggests, social interventions should aim at more among the subnormal births. This study suggest that tackling inequality in births as well as infant mortality should be focused on the social inequality itself.

• Journal of Korean Neurosurgical Society
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• 제64권3호
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• pp.460-468
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• 2021

Objective : Extremely low alanine transaminase (ALT) levels are associated with all-cause mortality in frail elderly individuals; the clinical significance of ALT as a reliable biomarker is now being considered. Predicting mortality with routine tests at the time of diagnosis is important for managing patients after intracranial hemorrhage. We aimed to investigate whether an extremely low ALT level is associated with mortality in the elderly after intracranial hemorrhage. Methods : A retrospective review was performed on 455 patients with intracranial hemorrhage admitted to a university-affiliated tertiary care hospital from February 2014 to May 2019. Multivariate Cox regression analysis was performed for all ages and for each age group to determine whether an extremely low ALT level is an independent predictor of mortality only in the elderly. Results : Overall, 294 patients were enrolled, and the mean age of the subjects was 59.1 years, with 99 (33.8%) aged ≥65 years. The variables associated with all-cause mortality in all subjects were age, C-reactive protein (CRP) levels, hemoglobin (Hb) levels (<11 g/dL), and initial Glasgow coma scale (GCS) scores. In young patients, CRP, low Hb levels, and initial GCS scores were significantly associated with all-cause mortality. However, in the elderly (≥65 years), the variables significantly associated with all-cause mortality were extremely low levels of ALT (<10 U/L) (adjusted hazard ratio, 3.313; 95% confidence interval, 1.232-8.909; p=0.018) and initial GCS scores. Conclusion : Extremely low ALT level (<10 U/L) at the time of diagnosis is a significant risk factor for all-cause mortality in the elderly after intracranial hemorrhage.