• Nuclear Engineering and Technology
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• v.50 no.5
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• pp.648-653
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• 2018

Elimination of soluble boron from reactor design eliminates boron-induced reactivity accidents and leads to a more negative moderator temperature coefficient. However, a large negative moderator temperature coefficient can lead to large reactivity feedback that could allow the reactor to return to power when it cools down from hot full power to cold zero power. In soluble boron-free small modular reactor (SMR) design, only control rods are available to control such rapid core transient. The purpose of this study is to investigate whether an SMR would have enough control rod worth to compensate for large reactivity feedback. The investigation begins with classification of reactivity and completes an analysis of the reactivity balance in each reactor state for the SMR model. The control rod worth requirement obtained from the reactivity balance is a minimum control rod worth to maintain the reactor critical during the whole cycle. The minimum available rod worth must be larger than the control rod worth requirement to manipulate the reactor safely in each reactor state. It is found that the SMR does have enough control rod worth available during rapid transient to maintain the SMR at subcritical below k-effectives of 0.99 for both hot zero power and cold zero power.

• Journal of the military operations research society of Korea
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• v.16 no.1
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• pp.18-34
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• 1990

In light of the recent developments of transitory nature, it is likely that national defense decision-making will be more difficult to make for years to come. In other words, sudden changes in security environment would call into question the basic assumptions on which we have built our national defense planning and increase the number of the uncertain factors in the decision-making process; the subdivision and ramification of national defense management would increase the factors for decision-making and complicate even further the mutual interactions among these factors; the accelerated pace of sophistication and diversification of weapon systems and military technology would increase the risk of failure and system costs geometrically; and the reduced level of acceptance among the people on the sanctification of national defense in proportion to the rapid progress toward a more democratic and industrial society would engender an increased criticism or checking role by the National Assembly or by the mass media. As the changes in national defense environment and conditions create an innumerable number of new tasks, this paper intends to suggest a few core policy measures to improve the quality of national defense decision-making. More specifically, it proposes to 1) eradicate entirely the bureaucratic behavior and tendencies; 2) utilize actively the brain staff for quality assurance of decision-making; 3) and introduce and apply as a whole set, a total system, or an incorporated pack age the PPBEES(Planning-Programming-Budgeting-Executing-Evaluating-System)/LCMM (Life-Cycle Management Model for System Acquision), the OR/SA(Operations Research/Systems Analysis), and DMIS (Defense Management Information System).

• Journal of Environmental Science International
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• v.28 no.2
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• pp.191-201
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• 2019

This study suggested a vegetation restoration plan for a coastal area where the ecosystem conservation fund return project, targeting the whole area of Dalmaji-gil, located in Haeundae, Busan. After distinguishing if it would be a proper site for the operation of the ecosystem conservation fund return project by analyzing the ecological environment, human environment, and the current status of land owners, the target species for vegetation restoration was determined, and the facilities and programs were selected in accordance with the spatial division of the biosphere reserve. The basic direction is as follows. First, is the expansion of green space and the securement of life habitats downtown. Second, is the conservation of core areas by separating the conserved area from the space for use. Third, is the establishment of ecological resting space and the reinforcement of an ecological educational programs. The significance of this study is to suggest a vegetation restoration plan of a coastal area, fully utilizing the existing vegetation of the subject area, by suggesting the land use and flow planning, environmental improvement (vegetation restoration) plan, life habitats establishment plan, planting plan, and hydrologic plan, facilities, maintenance, and monitoring plan based on the basic direction. This study would provide useful basic data for ecosystem conservation and restoration in the Korean Peninsula, surrounded by the ocean on three sides.

• International Journal of Contents
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• v.14 no.4
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• pp.70-75
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• 2018

The purpose of this corpus-based study was to find 4-word lexical bundles in computer science research articles. As the demand for research articles (RAs) for international publication increases, the need for acquiring field-specific writing conventions for this academic genre has become a burning issue. Particularly, one area of burgeoning interest in the examination of rhetorical structures and linguistic features of RAs is the use of lexical bundles, the indispensable building blocks that make up an academic discourse. To illustrate, different academic discourses rely on distinctive repertoires of lexical bundles. Because lexical bundles are often acquired as a whole, the recurring multi-word sequences can be retrieved automatically to make written discourse more fluent and natural. Therefore, the proper use of rhetorical devices specific to a particular discipline can be a vital indicator of success within the discourse communities. Hence, to identify linguistic features that make up specific registers, this corpus-based study examines the types and usage frequency of lexical bundles in the discipline of CS, one of the most in-demand fields world over. Given that lexical bundles are empirically-derived formulaic multi-word units, identifying core lexical bundles used in RAs, they may provide insights into the specificity of particular CS text types. This will in turn provide empirical evidence of register specificity and technicality within the academic discourse of computer science. As in the results, pedagogical implications and suggestions for future research are discussed.

• Nuclear Engineering and Technology
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• v.51 no.5
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• pp.1218-1230
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• 2019

A sub-channel solver, named ${\underline{S}}teady$ and ${\underline{T}}ransient$ ${\underline{A}}nalyzer$ for ${\underline{R}}eactor$ ${\underline{T}}hermal$ hydraulics (START), has been developed using the homogenous model for two-phase conditions of light water reactors. The code is developed as a fast and accurate TH-solver for coupled and multi-physics calculations. START has been validated against the NUPEC PWR Sub-channel and Bundle Test (PSBT) database. Tests like single-channel quality and void-fraction for steady state, outlet fluid temperature for steady state, rod-bundle quality and void-fraction for both steady state and transient conditions have been analyzed and compared with experimental values. Results reveal a good accuracy of solution for both steady state and transient scenarios. Axially different values for turbulent mixing coefficient are used based on different grid-spacer types. This provides better results as compared to using a single value of turbulent mixing coefficient. Code-to-code evaluation of PSBT results by the START code compares well with other industrial codes. The START code has been parallelized with the OpenMP algorithm and its numerical performance is evaluated with a large whole PWR core. Scaling study of START shows a good parallel performance.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.19 no.4
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• pp.447-457
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• 2021

Graphite Isotope Ratio Method (GIRM) can be used to estimate plutonium production in a graphite-moderated reactor. This study presents verification results for the GIRM combined with a 3-D polynomial regression function to estimate cumulative plutonium production in a graphite-moderated reactor. Using the 3-D Monte-Carlo method, verification was done by comparing the cumulative plutonium production with the GIRM. The GIRM can estimate plutonium production for specific sampling points using a function that is based on an isotope ratio of impurity elements. In this study, the ¹⁰B/¹¹B isotope ratio was chosen and calculated for sampling points. Then, 3-D polynomial regression was used to derive a function that represents a whole core cumulative plutonium production map. To verify the accuracy of the GIRM with polynomial regression, the reference value of plutonium production was calculated using a Monte-Carlo code, MCS, up to 4250 days of depletion. Moreover, the amount of plutonium produced in certain axial layers and fuel pins at 1250, 2250, and 3250 days of depletion was obtained and used for additional verification. As a result, the difference in the total cumulative plutonium production based on the MCS and GIRM results was found below 3.1% with regard to the root mean square (RMS) error.

• Journal of the Daesoon Academy of Sciences
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• v.34
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• pp.293-321
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• 2020

The value embodied by "Ascending to Heaven and Being an Immortal" (Yuhua Dengxian in Chinese) implies the core gist of Daoist culture as well as its ultimate value. From the perspective of Philology, each word, "Yu", "Hua", "Deng", and "Xian" benefits us through a philosophy of life, learning skills, the pursuit of the mysteries of Daoist immortality, and the ways of life characteristics and spiritual transcendence. "To become an immortal" is becoming adept at life. "Yuhua" refers to learning transcendental skills, and "Deng" expresses the promotion of life. "Ascending to Heaven and Becoming an Immortal" integrates the goal- oriented values of Daoist Culture, learning transcendental skills, and the state of being alive into a unified whole. Namely, it is the perfect combination of an adept's supreme pursuit of value and zenith of life. By way of contrast, in Daesoon Jinrihoe, the concepts of "Daesoon" and "Perfected Unification with the Dao" not only advocate "physical and mental transformation" and "spiritual development" for Dao cohorts, but also personal cultivation and service to society, and participation in "The Creation of an Earthly Paradise." These are unified under the ideal humanistic value of "the earthly paradise of the Later World."

• BMB Reports
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• v.55 no.5
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• pp.238-243
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• 2022

Autism or autism spectrum disorder (ASD) is a behavioral syndrome characterized by persistent deficits in social interaction, and repetitive patterns of behavior, interests, or activities. The gene encoding Methyl-CpG binding protein 2 (MeCP2) is one of a few exceptional genes of established causal effect in ASD. Although genetically engineered mice studies may shed light on how MeCP2 loss affects synaptic activity patterns across the whole brain, such studies are not considered practical in ASD patients due to the overall level of impairment, and are technically challenging in mice. For the first time, we show that hippocampal MeCP2 knockdown produces behavioral abnormalities associated with autism-like traits in rats, providing a new strategy to investigate the efficacy of therapeutics in ASD. Ketamine, an N-Methyl-D-aspartate (NMDA) blocker, has been proposed as a possible treatment for autism. Using the MeCP2 knockdown rats in conjunction with a rat model of valproic acid (VPA)-induced ASD, we examined gene expression and ASD behaviors upon ketamine treatment. We report that the core symptoms of autism in MeCP2 knockdown rats with social impairment recovered dramatically following a single treatment with ketamine.

• Asia Marketing Journal
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• v.17 no.1
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• pp.1-26
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• 2015

In the 21^st century, green consumer behavior, playing one of the core roles of sustainability, is still an important issue to green-related stakeholders. Because one of the major objectives of green-consumer research is an improvement of behaviors aligned with greening, this paper revisited socio-demographic variables and shed light on segmenting and profiling green consumers based on their connectedness between socio-demographic variables and green behaviors. Using correlations, factor analysis, analysis of variance, k-means cluster analysis and χ²-tests, this paper shows that socio-demographic variables differentially impact green-consumer behaviors. In order to profile green consumers, this paper additionally attempts to segment green-consumer groups. The results also coincide with former findings that socio-demographic variables relate significantly with segmented green-consumer group behaviors. General findings are summarized as: 1) older people used green practices more strongly than younger people, 2) females demonstrated better energy-saving and recycling practices compared to males, 3) marital status also significantly influenced green-related behaviors, 4) subjective social class had a significant influence on green-related behaviors, 5) education level and income, however, weakly influenced or showed no impact on green-related behaviors, and 6) a green consumer was classified as an 'active green consumer,' 'utilitarian green consumer,' or 'inactivated green consumer.' The utilitarian green consumer group distinctively behaved more strongly in energy-saving and recycling practices compared to the inactivated green consumer group, whereas active green consumers behaved more strongly on the whole, when compared to those in the inactivated green consumer group.

• Human Ecology Research
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• v.62 no.2
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• pp.317-326
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• 2024

This study evaluated the thermal physiological and psychological responses elicited when wearing cold protective jackets with aerogel fillings in two cold environments, one without air velocities and one with air velocities (2.3 m·s-1), at an air temperature of 10℃. The participants were five healthy young males. Measures were taken of physiological parameters, blood pressure (BP), heart rate (HR), core temperature, oxygen uptake (Vo2), and microclimate (temperature and humidity). The psychological parameters evaluated were thermal and wetness sensation. No differences were observed in systolic blood pressure, heart rate, and oxygen intake between the conditions. At tympanic temperature, a significant difference was observed between the conditions during exercise (p<.05); . A significant difference was observed in the microclimate temperature of the clothing according to the airflow, and temperature changes in the chest and back revealed different patterns. Significant differences were observed in thermal sensation (whole body (p<.05), chest (p<.05), back (p<.01)) between airflow conditions. The results therefore indicate that cold protective jackets with an aerogel filling are suitable for people operating in low-temperature and airflow environments.