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        검색결과 21

        1.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Pinus densiflora is a fixed-growth coniferous species that elongates its shoot once a year and finishes growing in early summer. However, it may produce additional shoots in the same year in response to external stimuli, called abnormal shoot growth. This study investigated the effects of open-field summer warming and drought on the abnormal shoot growth of P. densiflora seedlings. In March 2022, two factorial combinations were constructed, including two temperature treatments (control and 4°C increase) and two precipitation treatments (control and drought), with five replicates for each combination. The temperature treatment was performed for 87 days from May 14 to August 8, 2022, and the precipitation treatment was performed for 33 days from May 14 to June 15, blocking 100% of the ambient rainfall. The abnormal shoot occurrence rate and leaf unfolding stages were measured in November, and the shoot and root collar diameter growth rates were calculated by comparing the seedling height and root collar diameter measured in August (after the cessation of treatment) and October (after the end of growing period) with the initial values (i.e., May 2022). The abnormal shoot occurrence rate significantly increased under the warming treatment, showing a 410.6% increase in the warming plots (38.4%) compared to the control plots (7.5%). There was no significant difference in the shoot and root collar diameter growth rate regarding warming and drought treatments. Abnormal shoots may have been affected by high temperatures by inducing early transition to the next ontogenetic stage.
        4,000원
        2.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        음악적 몰입은 음악 청취, 악기 연주 등의 음악 활동에 참여하는 동안 음악에 깊게 집중하고 있는 심리적 상태를 의미한다. 특히 음악을 청취하는 동안 나타나는 몰입은 청취자로 하여금 긍 정적인 감정을 경험하게 하며, 이때 몰입을 자주 경험하는 사람일수록 주관적 행복감이 높은 것으 로 나타났다. 그렇다면 음악 청취 시 나타나는 음악적 몰입 상태를 어떻게 규정할 수 있으며, 청 취자가 몰입을 경험하고 있다는 것을 확인할 수 있는 방법에는 무엇이 있을까? 인지과학, 신경과 학 분야에서 다양한 연구들이 음악 청취자의 몰입 상태를 과학적으로 평가하고 정량화하고자 시 도하고 있다. 그러나 기존 연구에서는 플로우(flow), 몰두(absorption), 참여(engagement) 등 몰입 을 설명하는 여러 개념들이 혼재되어 사용되고 있어 음악적 몰입 현상을 개념화하기 어렵다는 문 제가 있다. 본 연구에서는 몰입에 관한 다양한 논문 리뷰를 통해 음악 청취 활동 시 나타나는 몰 입 모형이 선행요인-몰입 상태-결과의 3단계로 구분될 수 있음을 칙센트미하이(Csikszentmihalyi) 의 플로우 이론에 기반하여 확인할 것이다. 또한, 음악 청취의 몰입을 행동적, 생리학적, 신경과학 적으로 정량화할 수 있는 방법론과 향후 연구 방향을 제안하고자 한다.
        9,000원
        3.
        2023.11 구독 인증기관·개인회원 무료
        Within the air purification system of a nuclear power plant, specific radioactive isotopes are extracted from gases through adsorption onto activated carbon. To properly dispose of used activated carbon, it is essential to determine the concentration of radioactive nuclides within it. This study discusses the application of the pyrolysis method for analyzing the concentrations of 3H and 14C in spent activated carbon. The pyrolysis was conducted using Raddec’s Pyrolyser, with adjustments made to parameters such as temperature profiles, airflow rates, sample quantities, and trapping solution volumes. The evaluation method for the pyrolysis of activated carbon to analyze 3H and 14C involved adding 3H and 14C sources to the activated carbon before use and subsequently assessing the recovery rates of the added sources in comparison to the analysis results.
        4.
        2023.11 구독 인증기관·개인회원 무료
        In the ocean, there exist infinite resources, including certain metallic elements that can serve as potential energy sources. One of the methods for extracting these dissolved resources from seawater involves adsorption. This study discusses the results of experiments conducted in real seawater using a developed fiber-type adsorbent capable of extracting dissolved oceanic resources. The fiber-type adsorbent was deployed in seawater to adsorb the elemental resources. It was then retrieved after 2, 3, and 4 weeks for evaluation of its adsorption performance. The evaluation was carried out by dissolving the adsorbent in a strong acidic solution and calculating the adsorption amount per gram of adsorbent using ICP-MS. The results indicated that the adsorption performance was slightly lower than previously reported values. Nevertheless, it confirmed the feasibility of adsorbing and recovering dissolved resources from actual seawater
        5.
        2023.11 구독 인증기관·개인회원 무료
        To evaluate the inventory of radionuclides for the disposal of waste generated from nuclear power plants, indirect assessment methods such as the scaling factor method or average radioactivity concentration method can be applied. A scaling factor represents the average concentration ratio between key radionuclides and difficult-to-measure (DTM) radionuclides, while the average radioactivity concentration refers to the average concentration of DTM radionuclides, regardless of the concentration of key radionuclides or within specific ranges of key radionuclide concentrations. These indirect assessment methods can be statistically derived through the analysis of representative drums. This study will address how to apply these scaling factors and average radioactivity concentrations. Firstly, the concentration of gamma-emitting radionuclides will be analyzed using a drum radionuclide analyzer, and the concentration of DTM radionuclides will be determined by applying scaling factors specific to each DTM radionuclide. In the case of using the average radioactivity concentration method, the average concentration of DTM radionuclides will be applied independently of the concentration of gamma-emitting radionuclides. It is crucial to perform radioactive decay correction based on the date of generation or disposal when applying scaling factors or average radioactivity concentration. Additionally, for repackaged 320 L drums, determining which drum among the two 200 L drums inside should serve as the reference is of utmost importance
        6.
        2023.11 구독 인증기관·개인회원 무료
        In order to apply indirect methods (such as scaling factors) to assess the radionuclide inventory of waste generated by nuclear power plants, it is essential to first evaluate the correlation coefficient between key radionuclides and those that are difficult to measure (DTM). The benchmark for the correlation coefficient (r) applied in indirect assessments is set at 0.6, and its significance can vary based on both its value and the size of the dataset. For instance, deriving a correlation coefficient using three data points versus utilizing a dataset with a hundred data points would yield different implications. This study addresses the variance in correlation coefficients based on data selection and presents a methodology for validating the significance of these coefficients. Additionally, we will discuss how these variances may impact the results of indirect assessments, such as scaling factor evaluations.
        7.
        2023.11 구독 인증기관·개인회원 무료
        To effectively assess the inventory of radionuclides generated from nuclear power plants using a consistent evaluation method across diverse groups, it is imperative to analyze the similarity in radioactive distribution between these groups. Various methodologies exist for evaluating this similarity, and the application of statistical approaches allows us to establish similarity at a specific confidence level while accounting for the dataset size (degrees of freedom). Initially, if the variance characteristics of the two groups are similar, a t-test for equal variances can be employed. However, if the variance characteristics differ, methods for unequal variances should be applied. This study delineates the approach for assessing the similarity in radioactive distribution based on the analytical characteristics of the two groups. Furthermore, it delves into the results obtained through two case studies to offer insights into the assessment process.
        8.
        2023.11 구독 인증기관·개인회원 무료
        For the disposal of radioactive waste from nuclear facilities, assessing their radioactivity inventories is essential. As a result, countries with nuclear facilities are implementing assessment schemes tailored to their respective policies and available resources for radioactive waste management. This paper specifically describes the assessment scheme for radioactivity inventory applied to metal waste generated during the dismantling of the Japan Power Demonstration Reactor (JPDR), a 1.25 MW BWR. The distinctive aspect of the Japanese approach lies in the fact that, for a pair of a key nuclide and a difficult-to-measure (DTM) nuclide that lack a significant correlation in their concentrations, the mean activity concentration method was used. In this method, an arithmetic average of all measurements of the DTM nuclide from representative drums, including MDAs (Minimum Detectable Activities), was assigned to the concentration of the DTM nuclide for all drums, regardless of the concentration of its paired key nuclide. Conversely, for a specific pair of a key nuclide and a DTM nuclide with a significant correlation, the scaling factor method was applied, as is common in many other countries. This Japanese case can serve as a valuable reference for Korea, which does not have the option of using the mean activity concentration method in its assessment scheme.
        9.
        2023.11 구독 인증기관·개인회원 무료
        To ensure the long-term supply and sustainability of uranium fuel, exploring alternative resources is essential, particularly considering that terrestrial reserves of uranium are limited (about 4.6 million tons). Since the amount of uranium dissolved in seawater is approximately 1000 times that of terrestrial reserves (i.e., about 4.5 billion tons), uranium extraction from seawater (UES) can be an alternative resource. However, the ultra-low concentration of uranium in seawater (about 3.3 ppb) poses a significant challenge in achieving economic feasibility for UES. This paper introduces case studies on the cost analysis of systems for recovering uranium from seawater, specifically focusing on braided fiber-based adsorbents developed by JAEA and ORNL. The cost analysis has been conducted based on using the deployment of these adsorbents on the bottom of the sea, which is a passive deployment method, thereby reducing the total costs of recovery. The analysis results can be used to identify R&D areas necessary for reducing cost components, making UES economically feasible.
        10.
        2023.05 구독 인증기관·개인회원 무료
        Given the limited terrestrial reserves of uranium (approximately 4.6 million tons), exploring alternative resources is necessary to secure a sustainable, long-term supply of nuclear energy. Uranium extraction from seawater (UES) is a potential solution since the amount of uranium dissolved in seawater (approximately 4.5 billion tons) is about 1,000 times that of terrestrial reserves. However, due to the ultra-low concentration of uranium in seawater (approximately 3.3 ppb), making UES economically viable is a challenging task. In this paper, we explore the potential of using thermal discharge from domestic nuclear power plants for uranium extraction. The motivation for this comes from previous research showing that the adsorption capacity of amidoxime-based adsorbents is proportional to the temperature of the seawater in which they are deployed. Specifically, a study conducted in Japan found that a 10°C increase in seawater temperature resulted in a 1.5-fold increase in adsorption capacity.
        11.
        2023.05 구독 인증기관·개인회원 무료
        Given the limited terrestrial reserves of uranium (about 4.6 million tons), exploring alternative resources is essential to ensure the long-term supply and sustainability of nuclear energy. Uranium extraction from seawater (UES) is a potential solution to this issue since the amount of uranium dissolved in seawater (about 4.5 billion tons) is approximately 1000 times that of terrestrial reserves. However, the ultra-low concentration of uranium in seawater (about 3.3 ppb) makes it a challenging task to make UES economically feasible. This paper provides an overview of the current status of UES technology, which has evolved over the past seven decades. Starting from inorganic adsorbents such as hydrous titanium oxide in the 1960s, amidoxime-based fibrous adsorbents gained the most attention until the early 2010s due to their ease of deployment in actual seawater conditions and high affinity for uranium. Nowadays, research on organic adsorbents with microstructures is prevailing due to their ability to easily control surface area and compositions. In addition, this study identifies the key issues that need to be addressed to make UES technology economically viable.
        18.
        2016.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We performed this study to understand the effect of a single-crystalline anode on the mechanical properties of asdeposited films during electrochemical deposition. We used a (111) single- crystalline Cu plate as an anode, and Si substrates with Cr/Au conductive seed layers were prepared for the cathode. Electrodeposition was performed with a standard 3-electrode system in copper sulfate electrolyte. Interestingly, the grain boundaries of the as-deposited Cu thin films using single-crystalline Cu anode were not distinct; this is in contrast to the easily recognizable grain boundaries of the Cu thin films that were formed using a poly-crystalline Cu anode. Tensile testing was performed to obtain the mechanical properties of the Cu thin films. Ultimate tensile strength and elongation to failure of the Cu thin films fabricated using the (111) single-crystalline Cu anode were found to have increased by approximately 52 % and 37%, respectively, compared with those values of the Cu thin films fabricated using apoly-crystalline Cu anode. We applied ultrasonic irradiation during electrodeposition to disturb the uniform stream; we then observed no single-crystalline anode effect. Consequently, it is presumed that the single-crystalline Cu anode can induce a directional/uniform stream of ions in the electrolyte that can create films with smeared grain boundaries, which boundaries strongly affect the mechanical properties of the electrodeposited Cu films.
        4,000원
        20.
        2012.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study examined whether vocabulary knowledge has meaningful effects on reading comprehension of Korean high school EFL learners and investigated which specific type of vocabulary knowledge, between vocabulary breadth and depth, plays a bigger role in reading comprehension when the learners’ English language proficiency is taken into account. The participants of this study were ninety eight high school EFL learners in Seoul, Korea, and they were tested on a series of measures tapping on their reading comprehension abilities and vocabulary knowledge in two different dimensions (vocabulary breadth and depth). Their listening comprehension abilities were also measured in order to control for the effects of general oral language comprehension abilities known to be the foremost contributor to reading comprehension and thus to enable focused analysis of the role of vocabulary knowledge. The study findings revealed that 1) vocabulary knowledge itself played a critical role in predicting reading comprehension abilities even after controlling for their listening comprehension abilities and that 2) compared to vocabulary breadth, vocabulary depth played a relatively more important role in predicting reading comprehension, regardless of the learners’ language proficiency. The findings provide important implications for vocabulary and reading comprehension instructions for Korean EFL students.
        6,000원
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