• KSBB Journal
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• v.14 no.6
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• pp.731-736
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• 1999

87 microbes were isolated from dyeing wastewater collected at Dongducheon and Banweol industrial complex. Five microbes showed excellent ability of color removal and were identified as Shewanella putrefaciens, Aeromonas salmonicida(3 different strains), and Pseudomonas vesicularis. Five identified strains had optimal pH and optimal temperature as 7.0 and 30$^{\circ}C$ for cultivation, and showed morphological characteristics of Gram negative, oxidase negative, rod shape, and non-motility, but their biochemical characteristics were distinguishable. Each single strain of five microbes were tested in the 500 mL flask to treat dyeing wastewater, and achieved about 35% color removal efficiency in average. When two strains were selected and applied to the treatment at same time, color removal efficiency was increased up to 65%. While three or more associations of each strain did not show the improvement of color removal. Inhibition effects by $Mn^{2+}\;and\;Fe^{3+}$ on the dye degradation were tested and resulted in no effect under 70 ppm concentration.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.4
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• pp.426-435
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• 2013

In this paper, we propose the MIMO circular polarization feed network to enhance the communication performances from the previous $2{\times}2$ MIMO channel to $4{\times}4$ channel for Land Mobile Satellite communication system. The only possibility to extend the communication channel is to use the additional satellite because of the limitation of satellite spaces to install additional antennas. For overcoming this problems, we propose the MIMO circular polarization feed network to secure the isolation characteristics without the distant antenna space. The port isolation characteristics and each port impedance matching conditions are numerically verified and we suggest the $4{\times}4$ MIMO channel model of the proposed system and the performances are verified. The fabricated circular polarization patch antennas with the proposed feed network are measured in the reverberation chamber and 7~10 dB of diversity gain and 80 % increasement of channel capacity are obtained.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.11
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• pp.1646-1649
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• 2012

The $O_2$ annealing technique has considerably suppressed the leakage current of GaN power devices, but this forms NiO at Ni-based Schottky contact with increasing on-resistance. The purpose of the present study was to fabricate 1.5 kV GaN Schottky barrier diodes by improving $O_2$-annealing process and GaN buffer. The proposed $O_2$ annealing performed after alloying ohmic contacts in order to avoid NiO construction. The ohmic contact resistance ($R_C$) was degraded from 0.43 to $3.42{\Omega}-mm$ after $O_2$ annealing at $800^{\circ}C$. We can decrease RC by lowering temperature of $O_2$ annealing. The isolation resistance of test structure which indicated the surface and buffer leakage current was significantly increased from $2.43{\times}10^7$ to $1.32{\times}10^{13}{\Omega}$ due to $O_2$ annealing. The improvement of isolation resistance can be caused by formation of group-III oxides on the surface. The leakage current of GaN Schottky barrier diode was also suppressed from $2.38{\times}10^{-5}$ to $1.68{\times}10^{-7}$ A/mm at -100 V by $O_2$ annealing. The GaN Schottky barrier diodes achieved the high breakdown voltage of 700, 1400, and 1530 V at the anode-cathode distance of 5, 10, and $20{\mu}m$, respectively. The optimized $O_2$ annealing and $4{\mu}m$-thick C-doped GaN buffer obtained the high breakdown voltage at short drift length. The proposed $O_2$ annealing is suitable for next-generation GaN power switches due to the simple process and the low the leakage current.

• ALGAE
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• v.35 no.1
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• pp.91-106
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• 2020

Incorporating renewable fuel into practice, especially from algae, is a promising approach in reducing fossil fuel dependency. Algae are an exceptional feedstock since they produce abundant biomass and oils in short timeframes. Algae also produce high-valued lipid products suitable for human nutrition and supplement. Achieving goals of producing algae fuels and high-valued lipids at competitive prices involves further improvement of technology, especially better control over cultivation. Manipulating microalgae cultivation conditions to prevent contamination is essential in addition to promoting optimal growth and lipid yields. Contamination of algal cultures is a major impediment to algae cultivation that can however be mitigated by choosing extremophile microalgae. This work describes the isolation of alkali-tolerant / alkaliphilic microalgae native to South Florida with ideal characteristics for cultivation. For that purpose, water samples from Lake Okeechobee were inoculated into Zarrouk's medium (pH 9-12) and incubated for 35 days. Selection resulted in isolation of three strains that were screened for biomass and lipid accumulation. Two alkali-tolerant algae Chloroidium sp. 154-1 and Chlorella sp. 154-2 were poor lipid accumulators. One of the isolates, the diatom Fistulifera sp. 154-3, was identified as a lipid accumulating, alkaliphilic organism capable of producing 0.233 g L^-1 d^-1 dry biomass and a lipid content of 20-30% dry weight. Lipid analysis indicated the most abundant fatty acid within Fistulifera sp. was palmitoleic acid (52%), or omega-7, followed by palmitic acid (17%), and then eicosapentanoic acid (15%). 18S rRNA phylogenetic analysis formed a well-supported clade with Fistulifera species.

• Anxiety and mood
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• v.18 no.1
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• pp.10-16
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• 2022

Objective : The present study examined the effectiveness of the mindful self-compassion (MSC) program on anxiety, depression, self-compassion and emotion regulation. Methods : A total of 29 subjects (mean age 27.5±6.5 years, 15 males and 14 females) participated in a standardized 8-week MSC program. The control group consisted of age- and sex-matched twenty participants (mean age 26.0±2.9 years, 11 males and 9 females). All subjects completed self-report measurements at two weeks before and after the MSC program. Results : MSC training improved self-compassion as demonstrated by the significant group x time interaction effects on the total Self-Compassion Scale scores (F[1, 47]=8.324, p<0.01). Regarding the subscale scores, a significant improvement in self-kindness, isolation and mindfulness components of self-compassion was observed after MSC training. A significant group x time interaction was observed on the self-kindness subscale (F[1, 47]=4.664, p<0.05), with a significant main effect of time (F[1, 47]=23.723, p<0.001). The isolation subscale showed a significant group x time interaction (F[1, 47]=8.698, p<0.001). For the mindfulness subscale, there was a significant group x time interaction (F[1, 47]=6.611, p<0.05) and main effect of time (F[1, 47]=6.611, p<0.05). MSC training also improved the acceptance emotion regulation strategy, as demonstrated by the significant group x time interaction in the acceptance subscale scores of the Cognitive Emotion Regulation Questionnaire (F[1, 47]=6.845, p<0.05). Conclusion : MSC training showed efficacy in fostering self-compassion and improving emotion regulation. Thus, this program might be applicable to improve mental health.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.2
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• pp.195-200
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• 1985

This experiment was carried out to know the processes of protoplast isolation, culture and plant regeneration in aims of introducing foreign genes into plant cells through plant gene vector, and cellular selection for plant improvement. The main results indicated that 2% cellulase plus 0.5% macerozyme is proper for isolation of protoplasts from leaf mesophyll cells of N. plumbaginifolia, plating efficiency was higher in 1.4-2.0 x 10$^4$ cells/ml, complete cell wall was regenerated after 2 days culture, cell division and cell mass were observed after 4 days and 2 weeks, respectively, colony was developed after 3 weeks culture, addition of 1-2mg/l BA promoted shoot differentiation while root differentiation did not required hormone and seeds were harvested from more than 100 cell lines for further investigation and study.

• Journal of Korea Water Resources Association
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• v.48 no.8
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• pp.613-623
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• 2015

To overcome the difficulties of discharge measurements during flood season, MWSCM(micowave water surface current meter) which measures river surface velocities without contacting water has been applied in field work since its development. The existing version of MWSCM is for floods so that its applicability is low due to the short periods of floods. Therefore the renovative redesign of MWSCM to increase the applicability was conducted so that it can be applied to the discharge measurements during normal flows as well as flood ones by extending the measurable range of velocity. A newly developed high-performance MWSCM for general use can measure the velocity range of 0.03-20.0 m/s from flood flows to normal flows, whereas MWSCM for floods can measure the velocity range of 0.5-10.0 m/s. The improvement of antenna isolation between transmitter and receiver to block the inflow of transmitted singals to receiver and the improvement of phase noise of oscillator are necessary for detecting low velocity with MWSCM technology. Separate type antenna of transmitting and receiving signals is developed for isolation enhancement and phase locked loop synthesizer as an oscillator is applied to high-performance MWSCM for general use. Microwave frequency of 24 GHz is applied to the new MWSCM rather than 10 GHz to make the new MWSCM small and light for convenient use of it at fields. Improvement requests on MWSCM for floods-stable velocity measurement, self test, low power consumtion, and waterproof and dampproof-from the users of it has been reflected on the development of the new version of MWSCM.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.11
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• pp.1228-1237
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• 2005

In order to predict the long-term effects of pollutants in sediment on the water quality and the improvement of water quality according to dredging operation, models applied to decide the location and the propriety of dredging were developed. At first, the area was divided into several segments and the developed model was applied to simulate the behaviors of contaminants in an aquatic environment by using estimated parameters. And then through the sensitivity analysis between parameters, the optimum values were determined. The long-term modelling in the area A forecasted that PCBs concentration in the hot spot was decreased from $3.1\;{\mu}g/L$ to $2.4\;{\mu}g/L$ in 30 years. Contaminants in sediment as a source of water pollution did not reduce remarkably in the long run. Therefore it is difficult to expect the improvement of water qualities without the fundamental isolation of contaminants from sediment. It is considered that the selective dredging in the spot improves the water quality consequently.

• English Language & Literature Teaching
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• v.15 no.2
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• pp.261-280
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• 2009

This study focuses on providing the pedagogical implications of stress in English pronunciation teaching since stress is one the most important characteristic factors in English pronunciation (Bolinger, 1976; Brown, 1994; Celce-Murcia, Brinton & Goodwin, 1996; Kreidler, 1989). The author investigated stress production regarding in terms of duration, pitch, and intensity by a group of native speakers of English and a group of low-proficiency South Kyungsang Korean college students for their pre-test. For both of the pre- and post-test, the same stimuli, which consisted of a one-syllable word, two two-syllable words, three three-syllable words, and three four-syllable words, were used along with the various sentence positions: isolation, initial, medial, and final. Soft ware programs, ALVIN and Praat, were used to record and analyze the data. Since Celce-Murcia et al. (1996), Klatt (1975), and Ladefoged (2001) treat duration of the stressed syllable more significantly than other factors, pitch and intensity, with respect to the listener's point of view, the author developed a special method of teaching English stress using a traditional Korean drum to emphasize duration. In addition, the results from the native speakers' production showed that their main strategy to realize stress was through lengthening stressed syllables. After six weeks of stress instruction using the drum, the production of the native speakers and the SK Korean participants from the pre- and post-test were compared. The results from the post-test indicated that the participants showed great improvement not only in duration but also in pitch after the stress instruction. Pitch improvement was unexpected but well-explained by the statement that long vowels receive accent in loan word adaptation in North Kyungsang Korean. The results also showed that the Korean participants' pitch values became more even in their duration values for each syllable as the structure of the word or the sentence became more complex, due to their dependency upon their L1.

• Journal of IKEEE
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• v.20 no.3
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• pp.251-259
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• 2016

This paper describes that how to enhance the robustness of semiconductor TRM(Transmitter and Receiver Module) through the bias sequencing and tuning the switching time. Previous circuit designs focused on improving the MDS(Minimum Detection Signal) performance. Because TRM has critical problem which transmission output signal leak into receiver by it's compact design. Under this condition, TRM was frequently broken down within the MTBF(Mean Time Between Failure). This study proposes the bias sequencing and tuning the switching time to improve above problem. At first, we collected major failure symptom and infer it's cause. Second, we demonstrated it's effect by derive the improvement method and apply it to our system. And finally we can convinced that the proposed method clear the frequent failure problem with its lack of isolation.