• Journal of environmental and Sanitary engineering
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• v.11 no.1
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• pp.27-37
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• 1996

The taxa of phytoplankton in the Dongbok reservoir consisted of 6 classes, 9 orders, 4 4 suborders, 21 families, 42 genus, 86 species, 4 varieties and 1 formula; totally 91 t taxa appeared. It contained 3 major groups that is Chlorophyceae 51 taxa(56.0 % the most high rate), Bacillariophyceae 23taxa(25.2%), Cyanophyceae 10taxa(10.9%). The most abundant with 47 taxa was in December, the least with 11 taxa was in March during research every month. The component ratio of biomass each main groups, Bacillariophyceae(51 %, the most h high rate), Cyanophyceae(38.9%), Chlorophyceae(9.8%). The most abundant class at the biomass component ratio were Cyanophyceae which contained 82.6-98.0 % of it in May and September, Chlorophyceae 79.0% in August, and Bacillariophyceae increased continuously, specially in winter and autumn. The seasonal dominant groups were Microcystis aemginosa belong to Cyanophyceae in spring and autumn, some species of Chlorophyceae in summer and Melosira granulata belong to Bacillariophyceae in winter and late autumn. Dominant index ranged from 0.33 to 0.95. The season of the lowest index was autumn and the highest was spring. Species diversity indices ranged from 1.09 to 3.99. The water environmental factors of the Dongbok reservoir were that the values of water temperature ranged between $2.4~28.9^{\circ}C$, pH 7.2~8.3, conductivity 77.0~105.5us/cm, and transparency 1.2~2.8m, also the concentration of dissolved oxygen(DO) ranged of 6.9-14.6mg/L, total nitrogen(T-N) 0.38-1.84mg/L, total phosphorus (T-P) 0.011~0.028mg/L, and chlorophyll-a $7.0~29.9mg/m^3$. In this research the proper temperature of water for algae growth, $15~20^{\circ}C$, was maintained in April. May, November and December 1 The number of species that induced water color were 14 species, that caused taste-and-odor problems were 3 species and that caused filter clogging were 5 species. A Among them, the bloom of Anahaena macrospora that caused odor problem occurred l in May and of Microcystis aeruRinosa and M. lνensenberRii that caused filter clogging in May and September.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1240-1243
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• 2008

The 6- inch electrowetting display (EWD) can be successfully developed by ink jet printing (IJP) technique. Due to the drop-on-demand characteristic of IJP technology, colored oil can be precisely dosed into the unit pixel. Here, we present the active matrix EWD in this article. By adopting this technique to dose different colored oils, single layer Multi-color EWD without adopting color filter can be achieved in the future.

• Korean Journal of Ecology and Environment
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• v.51 no.3
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• pp.245-252
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• 2018

Stable isotope tracers were first applied to evaluate the Microcystis cell assimilation efficiency of bivalves, since the past identification method has been limited to tracking the changes of each chl-a, clearity, and nutrient. The filter-feeders (Sinanodonta woodiana and Unio douglasiae) were assessed under the condition of cyanobacteria (Microcystis aeruginosa) blooms through an in mesocosm experiment using $^{13}C$ and $^{15}N$ dual isotope tracers. chl-a concentration in the treatment mesocosm was dramatically decreased after the beginning of the second day, ranging from 116 to $66{\mu}g\;L^{-1}$. In addition, the incorporated $^{13}C$ and $^{15}N$ atom % in the S. woodiana bivalve showed higher values than U. douglasiae bivalves. The results demonstrate that U. douglasiae has less capacity to assimilate toxic cyanobacteria derived from diet. Our results therefore also indicate that S. woodiana can eliminate the toxin more rapidly than U. douglasiae, having a larger detoxification capacity.

• New & Renewable Energy
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• v.9 no.3
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• pp.36-42
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• 2013

To secure raw materials of biodiesel production, the possibility of camellia (C. japonica L.) and tea (C. sinensis L.) seed oil was studied to produce biodiesel. In this research, crude oil contents and fatty acid compositions of seeds were analyzed by Solxlet and Gas chromatography (GC). The oil contents in the seeds of camellia were 69.8%~73.8%, and tea were 26.3%~29.4%. Among the fatty acids of camellia and tea oil, oleic acid was dominant. The unsaturated fatty acids accounted for 88.4% and 80.2% of the whole fatty acids of camellia and tea seed oil. Total seed oil content and fatty acid composition of tea seed were influenced by collecting date. Across maturation period, oil content of tea seed averaged 18.3% on $6^{th}$ September increasing to 27.9% by $11^{th}$ October. For largest seed yield and oil content, the optimum time to harvest tea is in middle october, and camellia is late september and thereafter. The extraction efficiency of oil from seeds by extraction methods was determined. Biodiesel were synthesized in 92.1~92.8% yields from camellia and tea oils by transesterification. The biodiesel was characterized by its physical and fuel properties including oxidation stability, iodine value and cold filter plugging point (CFPP). Oxidation stability of camellia was 8.6~8.8 hours and tea was 2.9~3.6 at $110^{\circ}C$. Camellia oil had considerably better oxidation stability and CFPP than tea oil.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.31 no.3
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• pp.199-218
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• 2005

Purpose of Study: Peripheral nerve regeneration depends on neurotrophism of distal nerve stump, recovery potential of neuron, supporting cell like Schwann cell and neurotrophic factors such as BDNF. Peripheral nerve regeneration can be enhanced by the conduit which connects the both sides of transected nerve. The conduit maintains the effects of neurotrophism and BDNF produced by Schwann cells which can be made by gene therapy. In this study, we tried to enhance the peripheral nerve regeneration by using calcium phosphate coated porous conduit and BDNF-Adenovirus infected Schwann cells in sciatic nerve of rats. Materials and Methods: Microporous filter which permits the tissue fluid essential for nerve regeneration and does not permit infiltration of fibroblasts, was made into 2mm diameter and 17mm length conduit. Then it was coated with calcium phosphate to improve the Schwann cell adhesion and survival. The coated filter was evaluated by SEM examination and MTT assay. For effective allogenic Schwann cell culture, dorsal root ganglia of 1-day old rat were extracted and treated with enzyme and antimitotic Ara-C. Human BDNF cDNA was obtained from cDNA library and amplified using PCR. BDNF gene was inserted into adenovirus shuttle vector pAACCMVpARS in which E1 was deleted. We infected the BDNF-Ad into 293 human mammary kidney cell-line and obtained the virus plaque 2 days later. RT-PCR was performed to evaluate the secretion of BDNF in infected Schwann cells. To determine the most optimal m.o.i of BDNF-Ad, we infected the Schwann cells with LacZ adenovirus in 1, 20, 50, 75, 100, 250 m.o.i for 2 hours and stained with ${\beta}$-galactosidase. Rats(n=24) weighing around 300g were used. Total 14mm sciatic nerve defect was made and connected with calcium phosphate coated conduits. Schwann cells$(1{\times}10^6)$ or BDNF-Ad infected Schwann cells$(1{\times}10^6)$ were injected in conduit and only media(MEM) was injected in control group. Twelve weeks after surgery, degree of nerve regeneration was evaluated with gait analysis, electrophysiologic measurements and histomorphometric analysis. Results: 1. Microporous Millipore filter was effective conduit which permitted the adhesion of Schwann cells and inhibited the adhesion of fibroblast. We could enhance the Schwann cell adhesion and survival by coating Millipore filter with calcium phosphate. 2. Schwann cell culture technique using repeated treatment of Ara-C and GDNF was established. The mean number of Schwann cells obtained 1 and 2 weeks after the culture were $1.54{\pm}4.0{\times}10^6$ and $9.66{\pm}9.6{\times}10^6$. 3. The mRNA of BDNF in BDNF-Ad infected Schwann cells was detected using RT-PCR. In Schwann cell $0.69\;{\mu}g/{\mu}l$ of DNA was detected and in BDNF-Adenovirus transfected Schwann cell $0.795\;{\mu}g/{\mu}l$ of DNA was detected. The most effective infection concentration was determined by LacZ Adenovirus and 75 m.o.i was found the most optimal. Conclusion: BDNF-Ad transfected Schwann cells successfully regenerated the 14mm nerve gap which was connected with calcium phosphate coated Millipore filter. The BDNF-Ad group showed better results compared with Schwann cells only group and control group in aspect to sciatic function index, electrophysiologic measurements and histomorphometric analysis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.5
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• pp.622-629
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• 2014

This study induced biological denitrification and nitrification via a biofiltration process with the view of removing nitrogen from land-based fish farm effluent. To achieve this, we operated an aquaculture nitrogen-removal system that includes a denitrification and nitrification reactor [working volume 40 L, flow rate 64.8 L, HRT (hydraulic retention time) 14.8 h, HRT considering recycling of NOx 7.4 h]. In the continuous process, the nitrification rate of ammonium nitrogen exceeded 90% at a steady state and the denitrification efficiency exceeded 80% with recycling to a pre-anoxic reactor. In addition, the pH in the final effluent was lower with a low influent water alkalinity averaging 100 mg/L (as $CaCO_3$). For effective denitrification reactions, carbon must be supplied via particulate organic matter (POM) hydrolysis because of the low C/N (carbon/nitrogen) ratio in the water.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.4
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• pp.54-61
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• 2014

Effects of artificial thermal aging on color variations of various commercial papers (fine paper, coated paper, newsprint and filter paper) were investigated. With thermal aging at $105^{\circ}C$, most of papers showed a special trend in $a^*-b^*$ plane: the $a^*$ (red-green) values of the samples were initially reduced (heading to - $a^*$ side) and after a turning point they increased to +$a^*$ side while the $b^*$(blue-yellow) values were kept increased to +$b^*$ side (yellowing of paper). Different papers had different turning points for $a^*$ value. The filter paper consisted of a pure chemical pulp and the copy paper with OBA (optical brightening agent) showed the latest turing points. In addition, the papers without OBA showed less reduction in brightness compared with that with OBA, suggesting that OBA could adversely influence the brightness stability during thermal aging.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.193-193
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• 2008

In this paper, a MMIC diplexer with a low pass and high pass filter are designed and fabricated using an InGaP/GaAs process. The design of this diplexer is based on its stabilization of the low insertion loss since it is important in the in-building system (IBS). The IBS integrates wire and wireless signal between the cable television (CATV) and the personal communication system. In this design, a dual-mode operation of diplexer is fabricated with the frequency of 0 Hz to 900 MHz and 1.7 GHz to 2.2 GHz for CATV and personal communication. respectively. The topolygy of the designed diplexer is based on the L-C filter. This diplexer fabricated by nanoENS Inc. which is foundry service company, was measured by using the facilities of the Kwangwoon University RFIC center. The fabricated chip size is $1.6\times1.4mm^2$ and it has abroad frequency range from 0 Hz to 2.2 GHz.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11A
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• pp.1159-1166
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• 2006

In this paper, we have designed a RFID reader receiver system for improving the performance of the passive Tag based 9$'908.5{\sim}914MHz'$ RFID reader, and analyzed the system performance according to the frequency, the reader, and tag properties. The commercial receive system causes a loss in sensitivity because of 24 capacitors and 6 inductors. So we have designed an improved system using a circulator, LNA and a SAW filter. The experimental results show that the use of a circulator to separate the Tx/Rx paths eliminates interference, the LNA improves the sensitivity of the Rx module and SAW filter eliminates the noise and spurious components in the received signal.

• Journal of Food Hygiene and Safety
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• v.33 no.5
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• pp.325-329
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• 2018

This study developed a rapid detection method for Bacillus cereus in fresh-cut cabbages. Fresh-cut cabbage samples were inoculated at 1-, 2- and 3-Log CFU/g, and pathogens were enriched in tryptic soy broth containing 0.15% polymyxin B at $30^{\circ}C$, $37^{\circ}C$, and $42^{\circ}C$ to determine the detection limit and appropriate enrichment temperature for multiplex PCR detection. Enriched bacterial cells in enrichment broth were collected in a hydrophobic filter prior to DNA extraction for multiplex PCR. Filters were resuspended in distilled water, and DNA was extracted from the suspension. DNA samples were further analyzed by multiplex PCR. Detection limit of multiplex PCR was 5-Log CFU/mL. B. cereus cell counts were higher (P < 0.05) at $42^{\circ}C$ than other temperatures. Detection rate of 1-, 2-, and 3-Log CFU/g inoculated samples were 60%, 80%, and 100% after enrichment respectively. However, when enriched samples were filtered with hydrophobic membrane filter, detection rates became 100%, regardless of inoculation level. Results indicate a combination of enrichment with hydrophobic filtration improves rapid detection efficiency of B. cereus in fresh-cut cabbage by multiplex PCR.