• Journal of the Korean Vacuum Society
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• v.22 no.5
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• pp.238-244
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• 2013

Doping process using laser is an important process in fabrication of solar cell for heat treatment. However, the process of using the furnace is difficult to form a selective emitter doping region. The case of using a selective emitter laser doping is required an expensive laser equipment and induce the wafer's structure damage due to high temperature. This study, we fabricated a new costly plasma source. Through this, we research the selective emitter doping. We fabricated that the atmospheric pressure plasma jet injected Ar gas is inputted a low frequency (a few tens kHz). We used shallow doping wafers existing PSG (Phosphorus Silicate Glass) on the shallow doping CZ P-type wafer. Atmospheric plasma treatment time was 15 s and 30 s, and current for making the plasma is 40 mA and 70 mA. We investigated a doping profile by using SIMS (Secondary Ion Mass Spectroscopy) and we grasp the sheet resistance of electrical character by using doping profile. As result of experiment, prolonged doping process time and highly plasma current occur a deeper doping depth, moreover improve sheet resistance. We grasped the wafer's surface damage after atmospheric pressure plasma doping by using SEM (Scanning Electron Microscopy). We check that wafer's surface is not changed after plasma doping and atmospheric pressure doping width is broaden by increase of plasma treatment time and current.

• Applied Chemistry for Engineering
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• v.9 no.2
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• pp.207-213
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• 1998

On the basis of the previous study[1], miscibility were investigated and intermolecular interaction strength for the miscibility were relatively compared for the blends poly{2,2-(m-phenylene)-5,5'-bibenzimidazole}(PBI) with two aromatic polyimides (PIs) synthesized by another dianhydride. Aromatic PAAs were prepared by the reaction of condensation of two diamines, 4,4'-methylene dianiline(4,4'-MDA) and 4,4'-oxydianiline(4,4'-ODA) with 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride(DSDA) using DMAc, and then converted into PIs after curing. PBI/PAA blends were prepared by solution blending. Cast films or precipitated powders of the PBI/PAA blends were cared at a high temperature to transform into PBI/PIs blends. Miscibility and specific intermolecular interaction for miscibility in the blends were investigated, and compared with previous polyimide structures of PBI/PIs blends [1]. Two blends, PBI/DSDA+4,4'-MDA(Blend-V) and PBI/DSDA+4,4'-ODA(Blend-VI), were found miscible : the evidences were optically clear films, synergistic single composition dependent $T_g{\prime}s$, and frequency shifts of N-H stretching band as much as $39{\sim}40cm^{-1}$, and of C=O stretching band near 1730 and $1780cm^{-1}$, 5~6 and $3{\sim}4cm^{-1}$, respectively. The specific intermolecular interactions existing between PBI and PIs were relatively analyzed with the area(A) formed between the $T_g{\prime}s$ of the measured and that of the calculated by the Fox equation at all compositions, the ${\kappa}$ values in Gordon-Taylor equation obtained from the measured $T_g{\prime}s$, and differences of the frequency shifts in the functional N-H and carbonyl stretching band. From the results, the area(A) and the ${\kappa}$ values for Blend-V and VI were smaller than those for Blend-III and IV used in previous study[1]. Differences of the frequency shifts in the functional groups(N-H and C=O) also showed similar tendency. Thus, specific intermolecular interaction strength in terms of hydrogen bonding of PBI/PI blends is dependent upon chemical structures of PIs, that is, PIs it seems that $SO_2$ group in dianhydride(DSDA) has weaker hydrogen bond strength than those of C=O in BTDA. In other words, it implies that the former occupied bulk space than the latter due to the sterric effect.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.4
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• pp.138-147
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• 2001

The stochiometric mixtures mixture of evaporating materials for the $ZnIn_{2}S_{4}$ single crystal thin film was prepared from horizontal furnace. To obtain the $ZnIn_{2}S_{4}$ single crystal thin film, $ZnIn_{2}S_{4}$ mixed crystal was deposited on throughly etched semi-insulting GaAs(100) in the Hot Wall Epitaxy(HWE) system. The sourceand substrate temperature were $610^{\circ}C$ and $450^{\circ}C$, respectively and the growth rate of the $ZnIn_{2}S_{4}$ single crystal thin film was about 0.5$\mu\textrm{m}$/hr. The crystalline structure of $ZnIn_{2}S_{4}$ single crystal thin film was investigated by photoluminescence and double crystal X-ray diffraction (DCXD) measurement. The carrier density and mobility of $ZnIn_{2}S_{4}$ single crystal thin film measured from Hal effect by van der Pauw method are $8.51{\times}10^{17}{\textrm}{cm}^{-3}$, 291$\textrm{cm}^2$/V.s at $293^{\circ}$K, respectively. From the photocurrent spectrum by illumination of perpendicular light on the c-axis of the $ZnIn_{2}S_{4}$ single crystal thin film, we have found that the values of spin orbit splitting $\Delta$So and the crystal filed splitting DCr were 0.0148eV and 0.1678 eV at $10^{\circ}$K, respectively. From the photoluminescence measurement of $ZnIn_{2}S_{4}$ single crystal thin film, we observed free excition($E_{X}$) typically observed only in high quality crystal and neutral donor bound exicton ($D^{\circ}$, X) having very strong peak intensity. The full width at half maximum and binding energy of neutral donor bound excition were 9meV and 26meV, respectively. The activation energy of impurity measured by Haynes rule was 130meV.

• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1164-1170
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• 1999

The physicochemical characteristics of ${\beta}-glucan$ isolated from waxy and non-waxy barley were investigated. The hull-less waxy and non-waxy barley containing 6.5% and 5.3% of total ${\beta}-glucan$ respectively, were used as a starting material. The yield and ${\beta}-glucan$ content of crude ${\beta}-glucan$ from waxy barley was 5.54% and 62.9%, respectively, and those were higher than 3.34% and 59.2% from non-waxy barley. The crude ${\beta}-glucan$ purified with selective precipitation and enzymatic treatment to obtain the ${\beta}-glucan$ isolate of high purity (>99%). The total yield of purified ${\beta}-glucan$ from waxy and non-waxy barley was 4.46% and 2.59%, respectively. The surface appearance of the purified ${\beta}-glucan$ by scanning electron microscopy (SEM) showed randomly entangled multi-net structure of ${\beta}-glucan$ microfibrils. The melting temperature of ${\beta}-glucan$ from waxy and non-waxy barley measured by differential scanning calorimetry (DSC) was $184.6^{\circ}C$, and $180.3^{\circ}C$, respectively. DSC endotherm of ${\beta}-glucan$ solution showed 2 peaks near $68^{\circ}C$ and $84^{\circ}C$. Enthalpy of phase transition was higher in non-waxy ${\beta}-glucan$ than waxy ${\beta}-glucan$, and the intrinsic viscosity of ${\beta}-glucan$ solution from waxy barley was higher than that of non-waxy ${\beta}-glucan$. The pasting viscosity of barley starch with the purified ${\beta}-glucan$ determined by Rapid Visco-Analyzer was higher than that of barley starch without ${\beta}-glucan$, and the effect of ${\beta}-glucan$ on increasing the paste viscosity was greater in non-waxy barley starch.

• Journal of Life Science
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• v.19 no.9
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• pp.1218-1225
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• 2009

Difractose anhydrides (DFAs) is studied as a sweetener for diabetics because of its structural property. DFAs have four types: DFA I, III, IV (degradation of levan) and V (degradation of inulin). Especially, DFA IV has been shown to enhance the absorption of calcium in experiments using rats. Levan fructotransferase is an enzyme for producing di-d-fructose-2,6':6,2-dianhydride (DFA IV). To identify structural characterization, we purified wild-type and mutants (D63A, D195N and N85S) of levan fructotransferase (LFTase) from Microbacterium sp. AL-210. These proteins were purified to apparent homogeneity by Ni-NTA affinity column, Q-sepharose ion exchange and gel filtration chromatography and detected by SDS-PAGE. They were also analyzed by circular dichroism (CD) measurements, JNET secondary structure prediction, activity measurements at various temperatures, and pH analysis. The optimum pH for the enzyme-catalyzed reaction was pH 7.5 and optimum temperature was observed at $55^{\circ}C$. Along with wild-type LFTase, mutants were analyzed by CD measurement, fluorescence analysis and differential scanning calorimetry (DSC). N85S showed less $\alpha$-helix and more $\beta$ strand than others. Also, N85S showed almost the same curve as wild-type in their steady-state fluorescence spectra, whereas mutant D63A and D195N showed higher intensity than wild-type. The amino acid sequence of wild-type LFTase was compared to the sequences of exo-inulinase from Aspergillus awamori, a plant fructan 1-exohydrolase from Cichorium intybus, and Thermotogo maritime (Tm) invertase and showed a high identity with Exo-inulinase from Aspergillus awamori.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.4
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• pp.337-343
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• 2009

Purpose: ((R)-1-(2-chlorophenyl)-N-1-[$^{11}$C]methyl-N(1-propyl)-3-isoquinoline carboxamide ((R)-PK11195) is a specific ligand for the peripheral type benzodiazepine receptor and a marker of activated microglia, used to measure inflammation in neurologic disorders. We report here that a direct and simple radiosynthesis of [$^{11}$C](R)-PK11195 in mild condition using NaH suspension in DMF and one-step loop method. Materials and Methods: (R)-N-Desmethyl-PK11195 (1 mg) in DMSO (0.1 mL) and NaH suspension in DMF (0.1 mL) were injected into a semi-prep HPLC loop. [$^{11}$C]methyl iodide was passed through HPLC loop at room temperature. Purification was performed using semi-preparative HPLC. Aliquots eluted at 11.3 min were collected and analyzed by analytical HPLC and mass spectrometer. Results: The labeling efficiency of [$^{11}$C](R)-PK11195 was 71.8$\pm$8.5%. The specific activity was 11.8:$\pm$6.4 GBq/$\mu$mol and radiochemical purity was higher than 99.2%. The mass spectrum of the product eluted at 11.3 min showed m/z peaks at 353.1 (M+1), indicating the mass and structure of (R)-PK11195. Conclusion: By the one-step loop method with the [$^{11}$C]CH3l automated synthesis module, [$^{11}C$](R)-PK11195 could be easily prepared in high radiochemical yield using NaH suspension in DMF.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.5
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• pp.423-435
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• 1984

The reproductive cycle of the small filefish, Rudarius ercodes was investigated based on the annual variations of gonadosomatic index(GSI) and hepatosomatic index(HSI) by electronic and photic microscophy. The specimens used were collected at the coastal area of Benden island, Sizuokagen, Japan, from September 1982 to August 1983. GSI began to increase from March, starting season of longer daylength and higher water temperature, and reached the maximum value between June and August. It began to decrease from September with the lowest value appearing between November and February without any evident variation. The annual variations of HSI were not distinct in male filefish and were negatively related to GSI in female : HSI decreased in the summer season when the ovary was getting mature and reached the maximum in the winter season when the ovary was getting retrogressive. The ovary consisted of a pair of saccular structure with numerous ovarian sacs branched toward the median cavity. Oogonia divided and proliferated along the germinal epithelium of the ovarian sac. Young oocytes with basophile cytoplasm showed several scattering nucleoli along the nuclear membrane. when the oocytes growing to about 300 ${\mu}m$, nuclear membrane to disappear with nucleus migrating toward the animal pole. The regions of protoplasm were extremely confined within the animal hemisphere in which most of cytoplasms were filled with yolk materials and oil drops. After ovulation, residual follicles and growing oocytes remaining in the ovarian sacs degenerated. But perinucleatic young oocytes without follicles formed were not degenerated, and growing continuously still in the next year. Mitochondria and endoplasmic reticula in the cytoplasm remarkably increased with oocytes maturing and yolk accumulating. Those were considered to be functionally related to the yolk accumulation. Five or six layers of possible vitellogenin, oval-shaped disc structures with high electron density, appeared in the apex of follicular processes stretching to the microvilli pits of mature oocytes. Testis consisting of a pair of lobular structures in the right and left were united in the posterior seminal vesicle, Cortex of testis was composed of several seminiferous tubules, and medulla consisting of many sperm ducts connected with tubules. Steroid hormone-secreting cells with numerous endoplasmic reticula and large mitochondria of well developed cristae were recognized in the interstitial cells of the growing testis. Axial filament of spermatozoon invaginated deeply in the central cavity of the nucleus and the head formed U-shape with acrosome severely lacking, mitochondria formed large globular paranuclei at the posterior head, and microtubular axoneme of the tail represented 9+9+2 type. The annual reproductive cycles could be divided into five successive stages : growth(March to July), maturation(May to September), Spawning(mid May to early October) and resting stages(October to February). The spawning peak occurred from June to August.

• Korean Journal of Environmental Biology
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• v.37 no.1
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• pp.93-108
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• 2019

To investigate the temporal-spatial distribution of picophytoplankton in relation to different water masses in the northern East China Sea (ECS), picophytoplankton abundance were investigated using flow cytometry with environmental factors in 2016-2017. The results from the analysis of flow cytometer data showed that Synechococcus appeared across all seasons, exhibiting its minimum abundance in winter and maximum abundance in summer. Furthermore, high abundance was detected in the surface mixed layer during spring and summer when vertical stratification occurs; in particular, Synechococcus exhibited maximum abundance in thermocline layer, indicating a close correlation to water temperature and thermocline formation. In addition, the abundance of Synechococcus indicated a decrease in the western seas in 2017 compared to 2016 under the strong influence of the Changjiang Diluted Water (CDW). This was determined by the significant influence of the CDW on the abundance of Synechococcus during summer in the northern waters of the ECS. In contrast, Prochlorococcus did not appear during winter and spring, and its distribution was limited during summer and autumn in the eastern seas under the influence of the Kuroshio current. The largest range of Prochlorococcus distribution was confirmed during autumn without the influence of the CDW. Thus, the distribution pattern of each picophytoplankton genus was found to be changing in accordance to the extension and reduction of sea current in different seasons and periods of time. This is anticipated to be a useful biological marker in understanding the distribution of sea currents and their influence in the northern waters of the ECS.

• Analytical Science and Technology
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• v.22 no.4
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• pp.285-292
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• 2009

It has been observed that, after long term storage, some ammunitions are misfired by tamping (combustionstopping) due to aging of the chemicals loaded in the ammunitions. Used in ammunitions are percussion powder which provides the initial energy, igniter which ignites the percussion powder, and a delay system that delays the combustion for a period of time. The percussion powder is loaded first, followed by the igniter and then the delay system, and the ammunitions explode by the energy being transferred in the same order. Tamping occurs by combustion-stopping of the igniter or insufficient energy transfer from the igniter to the delay system or the combustion-stopping of the delay system, which are suspected to be caused by low purity of the components, inappropriate mixing ratio, size distribution of particulate components, type of the binder, blending method, hydrolysis by the humidity penetrated during the long term storage, and chemical changes of the components by high temperature. Goal of this study is to find the causes of the combustion-stopping of the igniter and the delay system of the ammunitions after long term storage. In this study, a method was developed for testing of the combustion-stopping, and the size distributions of the particulate components were analyzed with field-flow fractionation (FFF), and then the mechanism of chemical change during long term storage was investigated by thermal analysis (differential scanning calorimetry), XRD (X-ray diffractometry), and XPS (X-ray photoelectron spectroscopy). For the ignition system, M (metal)-O (oxygen) and M-OH peaks were observed at the oxygen's 1s position in the XPS spectrum. It was also found by XRD that $Fe_3O_4$ was produced. Thus it can be concluded that the combustion-stopping is caused by reduction in energy due to oxidation of the igniter.

• Korean Journal of Remote Sensing
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• v.39 no.5_3
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• pp.979-995
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• 2023

As wildfires are difficult to predict, real-time monitoring is crucial for a timely response. Geostationary satellite images are very useful for active fire detection because they can monitor a vast area with high temporal resolution (e.g., 2 min). Existing satellite-based active fire detection algorithms detect thermal outliers using threshold values based on the statistical analysis of brightness temperature. However, the difficulty in establishing suitable thresholds for such threshold-based methods hinders their ability to detect fires with low intensity and achieve generalized performance. In light of these challenges, machine learning has emerged as a potential-solution. Until now, relatively simple techniques such as random forest, Vanilla convolutional neural network (CNN), and U-net have been applied for active fire detection. Therefore, this study proposed an active fire detection algorithm using state-of-the-art (SOTA) deep learning techniques using data from the Advanced Himawari Imager and evaluated it over East Asia and Australia. The SOTA model was developed by applying EfficientNet and lion optimizer, and the results were compared with the model using the Vanilla CNN structure. EfficientNet outperformed CNN with F1-scores of 0.88 and 0.83 in East Asia and Australia, respectively. The performance was better after using weighted loss, equal sampling, and image augmentation techniques to fix data imbalance issues compared to before the techniques were used, resulting in F1-scores of 0.92 in East Asia and 0.84 in Australia. It is anticipated that timely responses facilitated by the SOTA deep learning-based approach for active fire detection will effectively mitigate the damage caused by wildfires.