• 농촌계획
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• 제6권2호
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• pp.3-11
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• 2000

The high salt concentration of reclaimed tidelands in the beginning of reclamation interferes with the growth of most crops. Although the crops are cultivated in the unripened tidal reclaimed paddy fields after desalinization to be arable, they we apt to be injured from salt by the resalinization through accumulated salts in the root zone during the growing period. In oder to make the reasonable irrigation plan in the unripened tidal reclaimed paddy fields, the preventive water requirements of resalinization as well as leaching requirements have to be included in irrigation water requirements. The critical salinity for the normal growth of crops should be determined to estimate the preventive water requirements of resalinization, and the changes of salinity in soil and water should be analyzed during the growing period, In this study, the growth tests of crops were conducted by soil textures and water management methods in the experimental field with lysimeters, using the samples of good drainage soils and poor drainage soils. And the changes of salinity in soil and water during the growing period, were analyzed to obtain the basic data for determining the critical salinity and making the estimation criteria of the preventive water requirements of resalinization. As the results obtained from analyzing the changes of salinity during the growing period in the unripened tidal reclaimed paddy fields, the exchanging interval of water for the prevention of resalinization was estimated to be within two weeks in good drainage soils and a week in poor drainage soils. And the total exchanging requirements of water for the prevention of resalinization during the growing period was estimated to be over 280mm in good drainage soils and 540mm in poor drainage soils.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2009년도 추계학술대회
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• pp.152-153
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• 2009

개인의 감성에 영향을 미치는 요인은 개인적, 사회적, 문화적 요인이 중요한 비중을 차지한다. 여러 자료를 추적해보면 하나의 개체로서의 인간은 다른 개체와 마찬가지로 종족유지 본능이 가장 우선하며 생활경험을 통하여 그 종족유지의 극대화를 위하여 그 구성요소로서의 유전인자들이 최적화되는 방향으로 진화하고 있다고 볼 수 있다. 즉, 우리의 생체는 무엇이 우리의 종족유지를 위한 환경인지 경험을 통하여 터득하게 되고 새로운 내적, 외적 환경자극에 무의식적으로 직관적으로 대처하며, 감성이란 이러한 대처 양상의 하나라고 볼 수 있다. 본 연구에서는 이러한 관점에서 개인적, 사회적, 문화적 요인, 생애초기특정기간(critical period)의 경험, 감성유발 직전의 기분상태 등이 어떻게 감성에 영향을 미치는가를 고찰해보고자 한다.

• 영어어문교육
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• 제6호
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• pp.219-239
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• 2000

There has been a growing enthusiasm in Korea for the early education of English as a foreign language (EFL). The present study examined the validity of the Critical Period Hypothesis in terms of the Universal Grammar (UG), in three different types of learning contexts - first language (L1), second language (SL), and foreign language (FL) learning contexts. While previous research findings in L1 and SL learning contexts suggest that UG principles and parameters are accessible to language learners only for the early years of lifetime, this article argues that their results - and even the methods - cannot be applied to EFL settings and that independent studies on the EFL context are, required. It also proposes the recent UG notion of functional categories as the most appropriate subject in the discussion of Korean EFL learners' access to UG. Findings on foreign language contexts, including the author's own, strongly indicate that UG is not sensitive to learners' starting ages in FL settings. If young children in FL contexts cannot develop their interlanguage grammar based on UG, the existing teaching methods for young children should be revised.

• 대한수학회지
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• 제44권2호
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• pp.327-342
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• 2007

In this paper, a kind of pest-predator model with impulsive effect and infinite delay is considered by the method of chain transform. By using Floquet's theorem, it is shown that there exists a globally asymptotically stable periodic pest eradication solution when the impulsive period is less than or equal to some critical value which is a directly proportional function with respect to the population of release. Furthermore, it is proved that the system is permanent if the impulsive period is larger than some critical value. Finally, the results of the corresponding systems are compared, those results obtained in this paper are confirmed by numerical simulation.

• BMB Reports
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• 제56권9호
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• pp.469-481
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• 2023

The gut microbiome is widely recognized as a dynamic organ with a profound influence on human physiology and pathology. Extensive epidemiological and longitudinal cohort studies have provided compelling evidence that disruptions in the early-life microbiome can have long-lasting health implications. Various factors before, during, and after birth contribute to shaping the composition and function of the neonatal and infant microbiome. While these alterations can be partially restored over time, metabolic phenotypes may persist, necessitating research to identify the critical period for early intervention to achieve phenotypic recovery beyond microbiome composition. In this review, we provide current understanding of changes in the gut microbiota throughout life and the various factors affecting these changes. Specifically, we highlight the profound impact of early-life gut microbiota disruption on the development of diseases later in life and discuss perspectives on efforts to recover from such disruptions.

• 한국표면공학회지
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• 제32권3호
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• pp.410-415
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• 1999

The adhesion strength of sputtered copper films to Inconel substrates has been studied using the scratch test. The effects of substrate treatments before deposition such as chemical or ion bombardment etching were investigated by means of a mean critical load derived from a Weibull-like statistical analysis. It was found that the mean critical load was very weak unless the amorphous layer produced by mechanical polishing on the substrate surface was eliminated. Chemical etching in a nitric-hydrochloric acid bath was shown to have practically no effect on the enhancement of the adhesion. In contrast, the addition in this bath of nickel and copper sulphates allowed removal of the amorphous layer and an increase in the values of the mean critical load. However, it was observed that excessive chemical etching could cancel out the mean critical load enhancement. The results obtained in the case of ion bombardment etching pretreatments could be far higher than those obtained with chemical etching. Moreover, for a sufficiently long period of ion bombardment etching, the adhesion strength was so high that it was impossible to observe evidence of an adhesion failure.

• Computers and Concrete
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• 제21권4호
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• pp.419-429
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• 2018

Climate changes, such as increasing of $CO_2$ concentration and global warming, will impact on the carbonation service life of concrete structures. Moreover, slag blended concrete has a lower carbonation resistance than control concrete. This study presents a probabilistic numerical procedure for evaluating the impact of climate change on carbonation service life of slag blended concrete. This numerical procedure considers both corrosion initiation period and corrosion propagation period. First, in corrosion initiation period, by using an integrated hydration-carbonation model, the amount of carbonatable substances, porosity, and carbonation depth are calculated. The probability of corrosion initiation is determined through Monte Carlo method. Second, in corrosion propagation period, a probabilistic model is proposed to calculate the critical corrosion degree at surface cracking, the probability of surface cracking, and service life. Third, based on the service life in corrosion initiation period and corrosion propagation period, the whole service life is calculated. The analysis shows that for concrete structures with 50 years service life, after considering climate changes, the service life reduces about 7%.

• 영어어문교육
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• 제11권1호
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• pp.203-224
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• 2005

The purpose of this study is to justify the effects of role play with respect to speaking and listening functions and to provide the strategic methodology for improving English communicative competence of fifth grade primary school students. We can expand role play as a strategic teaching method to develop English learning models, so that English can be more easily acquired to the students who are in the critical language acquisition period. Strategic role play reflects the events and experiences of many kinds of people in everyday life. It is suggested that one of the best methods to improve English communicative competence in the primary classroom is through role play. Students can develop meaning for language patterns by portraying situations in which these instances in language would be used. This study proposes to facilitate English communicative ability using various student-centered role play strategies. It is concluded that the student-centered activities using strategic role play help the students to improve their English communicative competence. This is done by deriving their own creative dialogues and presenting the role play with their interests in learning English and with subsequently positive learning effects.

• 가정과삶의질연구
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• 제23권5호
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• pp.79-92
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• 2005

The purpose of this study was to explore the various perspectives to read micro-history of Korean housing after the period of Opening the Port for foreigners. This study were designed to adapt original theory for exploring the unique housing perspectives without using strict basic assumption which were already developed in the area of sociology, history, anthropology and philosophy. Research method applied was literature review. Each perspective might give useful insight to read the micro-history of Korean housing on the way of change after the Period of Opening the Port in Korea. Adapted perspectives to housing history were critical theory perspective, microsociological perspective, everyday life perspective(phenomenology tradition, symbolic interaction tradition, Marxist tradition), discourse perspective, exchange theory perspective, conflict theory perspective, and life course perspective. Conclusively, each perspective must be adapted multi-supportively to read the housing phenomena, because housing change derived from complex causes and factors. The fruit of this study was to ensure the adaptable viewpoint to housing were useful to read the micro-history of housing change.

• 한국의류학회지
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• 제19권3호
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• pp.516-524
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• 1995

The purpose of this study was to analyze the variation of body shape and to. divide growth period into some age groups based on body type. Duncan Test, Heath-Carter's somatotyping method and allottery equation (y=baa) were applied to semiautomatic data concerning obesity/leakiness. The materials were 309 females aged from 12 to 17 years old. The following results were obtained: 1. In the Developmental trend of the human body, the 12-13 age groups belonged to the acceleration stage of adolescent growth spurt. The 14-15 age groups belonged to the latter period of adolescent growth. The 16-17 age groups belonged to the termination stage of adolescent growth. 2. In the Heath-Carter's somatotyping method, the average somatotype changed into M.M- C-C-M-D with age. 3. In the alphamerical analysis, the first critical point appeared at the stature 146 Cm in case of weight, LBM and fat. The second critical point appeared at the stature 154-157 Cm in case of LBM and Fat. All the three measurement showed positive allotmentty.