• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.6
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• pp.239-245
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• 2022

Reduced graphene oxide (rGO) has attracted many attention and applications due to its excellent electrochemical ability. Therefore, standardization of rGO through structural and thermal analysis facilitates quality improvement and management, enabling users to increase efficiency and reduce relevant costs. For rGO and graphene-related materials, it is very important to determine the number of layers and define the resulting difference in physical properties. In this study, 3~4 layers of rGO-1 and 9~10 layers of rGO-2 were obtained from graphene oxide (GO) through a hydrazine reduction process. For the prepared rGOs, X-ray diffraction (XRD) pattern obtained a diffraction peak at 2θ≈25° related to (002) reflection was used to calculate the layer numbers by determining interlayer distance and FWHM value. To reduce the angular uncertainty, XRD data analysis was performed with angle correction using standard reference materials for X-ray powder diffraction analysis. Precise interlayer distance and number of layers were determined using OriginLab and open-source XRD diffraction analysis programs using the angle-corrected diffraction data. TG-DSC thermal analysis was performed to further standardize the physical properties of rGO samples.

• Nuclear Engineering and Technology
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• v.26 no.3
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• pp.337-344
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• 1994

Enthalpy rise hot channel factor($F_{\Delta{H}}$$^{N}$) is one of the most limiting constraints in determining the fuel loading pattern(LP) for PWR's. In order to enhance the LP design flexibility without any changes of not only basic fuel specifications but also Technical Specifications and Operation Procedures, we apply the enrichment zoning concept to Westinghouse designed PWR's to flatten the rod power distributions within the fuel assembly and thus to reduce $F_{\Delta{H}}$$^{N}$. Enrichment zoning is described that each assembly consists of two different enrichment fuels ; the lower enriched fuels are located in positions which are expected to have the higher rod power and vice versa for the higher enriched fuels. As a result of unit assembly calculations to flatten the rod power distribution within the assembly, the appropriate enrichment difference is found to be 0.3~0.4w/o. Through core depletion calculations for the 18-month cycle of Kori Unit 4, the $F_{\Delta{H}}$$^{N}$ behavior in core with the enrichment zoning concept is investigated. A comparison with the reference case without the enrichment zoning results in a reduction in $F_{\Delta{H}}$$^{N}$ of approximately 1.5%.TEX>H/$^{N}$ of approximately 1.5%.

• Design Convergence Study
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• v.16 no.6
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• pp.169-184
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• 2017

There is a lot of needs that are not expressed as much as the expressed needs in familiar products and services that are used in daily life such as a smartphone. Finding the 'Inconveniences in familiar use' make it possible to create opportunities for value expanding in the existing products and service area. There are a lot of related works, which have studied the definition of hidden needs and the methods to find it. But, they are making it difficult to address the hidden needs in the cases of familiar use due to focus on the new product or service developing typically. In this study, we try to redefine the hidden needs in the daily familiarity and approach it in the new way to find out. Because of the users' unability to express what they want and the complexity of needs which can not be explained clearly, we can not approach it as the quantitative issue. For this reason, the basic data type selected as the user behavior data excluding all description is the screen-shot of the smartphone. We try to apply the integrated rules and patterns to the individual data using the qualitative coding techniques to overcome the limitations of qualitative analysis based on unstructured data. From this process, We can not only extract meaningful clues which can make to understand the hidden needs but also identify the possibility as a way to discover hidden needs through the review of relevance to actual market trends. The process of finding hidden needs is not easy to systemize in itself, but we expect the possibility to be conducted a reference frame for finding hidden needs of other further studies.

• Journal of Korean Society of Forest Science
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• v.112 no.4
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• pp.459-471
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• 2023

This study identified the characteristics of changes in forest areas of North Korea's major regions (Gaesong, Goseong, Pyongyang, and Hyesan·Samsu) using data on degraded lands collected via monitoring by the National Institute of Forest Science. The data, spanning 1999 to 2018, were cross-analyzed to determine trends in land cover change, and hotspot analysis was conducted to confirm evident changes in the forest areas. The results showed that the areas of interest substantially transitioned to other land use types from 1999 to 2008. Contrastingly, the range of changes decreased from 2008 to 2018, with some areas regenerating into forests. Nevertheless, the hotspot analysis indicated that hotspots occurred more intensively in the outskirts of cities and forest edges from 2008 to 2018 than from 1999 to 2008. The analysis also showed that the aforementioned changes were caused by various aspects, depending on regional characteristics and social factors. This study can be used as a basic reference for decision-making on the selection of basic forest restoration targets and restoration methods in inter-Korean forest cooperation initiatives.

• The Journal of the Acoustical Society of Korea
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• v.25 no.5
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• pp.213-221
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• 2006

Phone segmentation of speech waveform is especially important for concatenative text to speech synthesis which uses segmented corpora for the construction of synthetic units. because the quality of synthesized speech depends critically on the accuracy of the segmentation. In the beginning. the phone segmentation was manually performed. but it brings the huge effort and the large time delay. HMM-based approaches adopted from automatic speech recognition are most widely used for automatic segmentation in speech synthesis, providing a consistent and accurate phone labeling scheme. Even the HMM-based approach has been successful, it may locate a phone boundary at a different position than expected. In this paper. we categorized adjacent phoneme pairs and analyzed the mismatches between hand-labeled transcriptions and HMM-based labels. Then we described the dominant error patterns that must be improved for the speech synthesis. For the experiment. hand labeled standard Korean speech DB from ETRI was used as a reference DB. Time difference larger than 20ms between hand-labeled phoneme boundary and auto-aligned boundary is treated as an automatic segmentation error. Our experimental results from female speaker revealed that plosive-vowel, affricate-vowel and vowel-liquid pairs showed high accuracies, 99%, 99.5% and 99% respectively. But stop-nasal, stop-liquid and nasal-liquid pairs showed very low accuracies, 45%, 50% and 55%. And these from male speaker revealed similar tendency.

• 한국균학회소식:학술대회논문집
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• 2015.05a
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• pp.53-53
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• 2015

Agrobacterium tumefaciens-mediated transformation(ATMT) of Flammulina velutipes was used to produce a diverse number of transformants to discover the functions of gene that is vital for its variation color, spore pattern and cellulolytic activity. Futhermore, the transformant pool will be used as a good genetic resource for studying gene functions. Agrobacterium-mediated transformation was conducted in order to generate intentional mutants of F. velutipes strain KACC42777. Then Agrobacterium tumefaciens AGL-1 harboring pBGgHg was transformed into F. velutipes. This method is use to determine the functional gene of F. velutipes. Inverse PCR was used to insert T-DNA into the tagged chromosomal DNA segments and conducting sequence analysis of the F. velutipes. But this experiment had trouble in diverse morphological mutants because of dikaryotic nature of mushroom. It needed to make monokaryotic fruiting varients which introduced genes of compatible mating types. In this study, next generation sequencing data was generated from 28 strains of Flammulina velutipes with different phenotypes using Illumina Hiseq platform. Filtered short reads were initially aligned to the reference genome (KACC42780) to construct a SNP matrix. And then we built a phylogenetic tree based on the validated SNPs. The inferred tree represented that white- and brown- fruitbody forming strains were generally separated although three brown strains, 4103, 4028, and 4195, were grouped with white ones. This topological relationship was consistently reappeared even when we used randomly selected SNPs. Group I containing 4062, 4148, and 4195 strains and group II containing 4188, 4190, and 4194 strains formed early-divergent lineages with robust nodal supports, suggesting that they are independent groups from the members in main clades. To elucidate the distinction between white-fruitbody forming strains isolated from Korea and Japan, phylogenetic analysis was performed using their SNP data with group I members as outgroup. However, no significant genetic variation was noticed in this study. A total of 28 strains of Flammulina velutipes were analyzed to identify the genomic regions responsible for producing white-fruiting body. NGS data was yielded by using Illumina Hiseq platform. Short reads were filtered by quality score and read length were mapped on the reference genome (KACC42780). Between the white- and brown fruitbody forming strains. There is a high possibility that SNPs can be detected among the white strains as homozygous because white phenotype is recessive in F. velutipes. Thus, we constructed SNP matrix within 8 white strains. SNPs discovered between mono3 and mono19, the parental monokaryotic strains of 4210 strain (white), were excluded from the candidate. If the genotypes of SNPs detected between white and brown strains were identical with those in mono3 and mono19 strains, they were included in candidate as a priority. As a result, if more than 5 candidates SNPs were localized in single gene, we regarded as they are possibly related to the white color. In F. velutipes genome, chr01, chr04, chr07,chr11 regions were identified to be associated with white fruitbody forming. White and Brown Fruitbody strains can be used as an identification marker for F. veluipes. We can develop some molecular markers to identify colored strains and discriminate national white varieties against Japanese ones.

• Progress in Medical Physics
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• v.24 no.1
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• pp.76-83
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• 2013

Previous studies about effect of respiratory motion on diagnostic imaging and radiation therapy have been performed by monitoring external motions but these can not reflect internal organ motion well. The aim of this study was to develope the artificial pulmonary nodule able to perform non-invasive implantation to dogs in the thorax and to evaluate applicability of the model to respiratory motion studies on PET image acquisition and radiation delivery by phantom studies. Artificial pulmonary nodule was developed on the basis of 8 Fr disposable gastric feeding tube. Four anesthetized dogs underwent implantation of the models via trachea and implanted locations of the models were confirmed by fluoroscopic images. Artificial pulmonary nodule models for PET injected $^{18}F$-FDG and mounted on the respiratory motion phantom. PET images of those acquired under static, 10-rpm- and 15-rpm-longitudinal round motion status. Artificial pulmonary nodule models for radiation delivery inserted glass dosemeter and mounted on the respiratory motion phantom. Radiation delivery was performed at 1 Gy under static, 10-rpm- and 15-rpm-longitudinal round motion status. Fluoroscpic images showed that all models implanted in the proximal caudal bronchiole and location of models changed as respiratory cycle. Artificial pulmonary nodule model showed motion artifact as respiratory motion on PET images. SNR of respiratory gated images was 7.21. which was decreased when compared with that of reference images 10.15. However, counts of respiratory images on profiles showed similar pattern with those of reference images when compared with those of static images, and it is assured that reconstruction of images using by respiratory gating improved image quality. Delivery dose to glass dosemeter inserted in the models were same under static and 10-rpm-longitudinal motion status with 0.91 Gy, but dose delivered under 15-rpm-longitudinal motion status was decreased with 0.90 Gy. Mild decrease of delivered radiation dose confirmed by electrometer. The model implanted in the proximal caudal bronchiole with high feasibility and reflected pulmonary internal motion on fluoroscopic images. Motion artifact could show on PET images and respiratory motion resulted in mild blurring during radiation delivery. So, the artificial pulmonary nodule model will be useful tools for study about evaluation of motion on diagnostic imaging and radiation therapy using laboratory animals.

• Radiation Oncology Journal
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• v.18 no.2
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• pp.120-126
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• 2000

Purpose : Tumor hypoxia can be overcome with hypoxic cytotoxin. In mouse tumor, tirapazamine's efficacy of the potentiating radiation effect was tested by the tumor oxygenation status combined with hype facti on ated rad iotherapy .:The control and hypoxic mouse tumors we established by inoculation of RIF-1 tumor cells into the normal or previously irradiated back and thigh of C3H mice. When the tumors reached a proper size, both the control and hypoxic tumors were given hypefractionated treatments (8fractions/4 days) with saline (0.02 ml/g), tirapazamin (0.08 mM/0.02 ml/kg), irradiation (2.5 Gy), irradiation combined with tirapazamine given 30 minutes prior to each irradiation. The response was evaluated by the growth delay assay by measuring tumor size from day 0 (12 hrs prior to the first fractionation) to the day when the volume had 4-fold increase or cross sectional area had 2-fold increase. Results : Overall growth pattern showed that tirapazamine Potentiated radiation effect in back and thigh tumors grew in the normal and preirradiated tumor bed. With growth delay assay using reference point of initial tumor volume or cross sectional area, tirapazamine potentiated radiation effect 1.9 times for the control and 2.4 times for the hypoxic tumors in back, and 1.85 times for the control and 1.6 times for the hypoxic tumors. With reference of 4-fold increase of the initial volume or 2-fold increase of the cross sectional area, tirapazamine potentiated radiation effect 1.48 times for the control and 2.02 times for the hypxic tumors in back, and 1.85 times for the control and 1.6 times for the hypoxic tumors. Conclusions : Present result indicated that radiation response of hypoxic tumors was potentiated by tirapazamine in the back or thigh tumors grew in the control or preirradiated tumor bed, and potentiation of the hypoxic tumors was eDual to or greater than that of the control tumors in the back or thigh.

• The Korean Journal of Nuclear Medicine
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• v.28 no.3
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• pp.282-292
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• 1994

Brain perfusion SPECT shows typical regional perfusion abnormalities in Alzheimer's disease(AD) and is useful for its diagnosis. However, there is also arguement that these patterns show significant overlap with other causes, and the accuracy for SPECT in differentiating AD has shown conflicting results. We postulate that the variation in re-ported results are partly due to a difference in patient or control selection with special reference to the mixture of ischemic cerebral disease in the studied population. To deter-mine the effect of ischemic lesions and the nature of control subjects on SPECT studies for AD, we performed $^{99m}Tc$-HMPAO single photon emission computed tomography (SPECT) in 11 probable AD patients with a low (<4) Hachinski ischemic score and 12 non-demented age matched controls. Magnetic resonance imaging(MRI) disclosed ischemic cerebral lesions in 27% (3/11) of the PAD group and 25% (3/12) of the control group. Regional perfusion indices were quantitated from the SPECT images as follows and the distribution of perfusion indices from both groups were compared. This was repeated with controls after excluding those with significant ischemic lesions by MRI : regional perfusion index = average regional count/average cerebellar count All PAD patients showed perfusion abnormality in SPECT. However, 53% (10/12) of controls also showed perfusion at-normalities, and no pattern could reliably differentiate the two groups. After excluding controls with significant cerebral ischemia, the difference in temporal and parietal perfusion index was increased. A decreased tempore-parietal and any parietal or temporal per-fusion index had a sensitivity of 18% and 36% in detecting AD, respectively. When using a separate group of normal age mathced controls, the indices showed an even more difference in the temporal and parietal lobes and the sensitivity of a decreased tempore-parietal and any parietal or temporal perfusion index had a sensitivity of 36% and 55% in detecting AD, respectively. Thus, the type of control with special reference to the pres-once of ischemic cerebral lesions contribute significantly to the accuracy of perfusion SPECT in diagnosing AD. This nay have particular importance in the diagnosis of AD in populations where the prevalance of cerebrovascular disease is high.

• Journal of Embryo Transfer
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• v.30 no.3
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• pp.175-181
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• 2015

The objective of this study was to monitor health conditions of genetically identical somatic cells cloned Korean white cattle, endangered indigenous cattle (EIC) and indigenous cattle (IC) by analysis of hematologic characteristics. Naturally ovulated oocytes and donor cells were used for somatic cell nuclear transfer (SCNT). Donor cells and enucleated oocytes were followed by electric fusion, chemical activation and surgical embryo transfer into the oviducts of surrogate females. Two recipients became pregnant; two maintained pregnancy to term, and one live cattle were delivered by caesarean section. The cloned Korean white cattle were genetically identical to the nuclear donor cattle. As a result, the mean values of RBC and platelet of cloned cattle and white cattle were significantly decreased by age (P<0.05). The mean values of RBC, HCT, MCV and MCHC between cloned cattle and IC of the same age (1~2 years) showed the statistical significance (P<0.05). Also, in the WBC of Korean white cattle, the estimated values were decreased according to the age from $12.0{\times}10^3/{\mu}l$ under 1 year to $11.0{\times}10^3/{\mu}l$ over 1 years respectively. Although clone-cattle had lower numbers of RBC than reference range, the most of RBC and WBC related heamatologic results of cloned cattle were not different when compared to reference range. This study suggests that cloned Korean white cattle derived from SCNT did not have remarkable health problems, at least in the growth pattern and hematological parameters. In addition, this study provides a valuable resource for further investigations of the preservation of rare genetic stocks underlying traits of interest in cattle.