• Carbon letters
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• v.23
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• pp.38-47
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• 2017

In this study, magnetite ($Fe_3O_4$) nanoparticles were electrochemically synthesized in an aqueous electrolyte at a given potential of -1.3 V for 180 s. Scanning electron microscopy revealed that dendrite-like $Fe_3O_4$ nanoparticles with a mean size of < 80 nm were electrodeposited on a glassy carbon electrode (GCE). The $Fe_3O_4/GCE$ was utilized for sensing chloramphenicol (CAP) by cyclic voltammetry and square wave voltammetry. A reduction peak of CAP at the $Fe_3O_4/GCE$ was observed at 0.62 V, whereas the uncoated GCE exhibited a very small response compared to that of the $Fe_3O_4/GCE$. The electrocatalytic ability of $Fe_3O_4$ was mainly attributed to the formation of Fe(VI) during the anodic scan, and its reduction to Fe(III) on the cathodic scan facilitated the sensing of CAP. The effects of pH and scan rate were measured to determine the optimum conditions at which the $Fe_3O_4/GCE$ exhibited the highest sensitivity with a lower detection limit. The reduction current for CAP was proportional to its concentration under optimized conditions in a range of $0.09-47{\mu}M$ with a correlation coefficient of 0.9919 and a limit of detection of $0.09{\mu}M$ (S/N=3). Moreover, the fabricated sensor exhibited anti-interference ability towards 4-nitrophenol, thiamphenicol, and 4-nitrobenzamide. The developed electrochemical sensor is a cost effective, reliable, and straightforward approach for the electrochemical determination of CAP in real time applications.

• Journal of Environmental Science International
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• v.15 no.7
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• pp.659-667
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• 2006

This research aims at applicability of adsorption process in order to satisfy the restricted Effluent Quality Standards for dyeing wastewater. The dyeing wastewater treated by biological process with carrier imbedded microorganisms was directly applied to the activated carbon adsorption in Process A, The dyeing wastewater treated by Fenton oxidation for the effluent of biological process was applied to the adsorption in Process B. It was found that the optimum conditions of adsorption with granular activated carbon are $20^{\circ}C$ and 120 minutes for the batch experiment. Langmuir equation was fitted better than Freundlich equation to the experimental data. The breakthrough time of adsorption column was determined by color rather than $COD_{Mn}$ for both Process A and Process B. The results revealed that the breakthrough time of adsorption for two processes was extended by the treatment of Fenton oxidation for dyeing wastewater treated by biological treatment than the direct application of dyeing wastewater treated by the biological treatment. Adsorption process can be applied in order to meet the restricted Effluent Quality Standards for dyeing wastewater.

• Mycobiology
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• v.42 no.2
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• pp.114-119
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• 2014

The wood decay fungi Antrodia P. Karst. play important ecological roles and have significant industrial and economic impacts as both wood degraders and sources of pharmaceutical and biotechnological products. Although each Antrodia species has distinct morphological characteristics, the misidentification rate is especially high due to their simple morphological characters. A combination of morphological and internal transcribed spacer region sequence analyses revealed that 27 of 89 specimens previously identified by morphology alone were correct, whereas 35 of these specimens were misidentified as other Antrodia species. We report here that seven Antrodia species exist in Korea (A. albida, A. heteromorpha, A. malicola, A. serialis, A. sinuosa, A. sitchensis, and A. xantha) and based on these specimens, we provide taxonomic descriptions of these species, except for A. serialis, which was only confirmed by isolate.

• Journal of Korean Society on Water Environment
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• v.25 no.5
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• pp.727-734
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• 2009

This study was carried out to evaluate the high rate biological reactor such as lab scale reactor before the application in site, and to get the basic data for possibility using liquid fertilizer with the effluent from biological reactor when the centrifugal machine was applied. The total volume of this reactor in 6 L, in composted of anoxic reactor (2 L), aerobic reactor (2 L), and nitification reactor (2 L). BOD removal efficiency rates when centrifugal machine was applied after effluent from biological reactor are over than 95%. This biological reactor was required post process to satisfy the effluent standards, and was need centrifugal machine to control the washout of microbes in the reactor. T-N removal efficiency rate in HRT 24 hr with centrifugation is 80.0%, and it is desirable to operate less than $1.3kgN/m^3{\cdot}d$ for 70% of T-N removal efficiency rate. T-P removal efficiency rate in HRT 24 hr is 68.2%, and become higher 71.3% after centrifugation. Considering in the 28.6% T-N removal efficiency rate, the nitrogen contents of the effluent from reactor is 0.34% to satisfy the liquid fertilizer.

• Journal of Korean Society on Water Environment
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• v.22 no.2
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• pp.230-237
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• 2006

The operational parameters and control strategies of a tertiary wastewater treatment process a biological filtration system were investigated. The biological filtration system consisted of a nitrification filter (Fiter 1) and a polishing filter with anoxic and aerobic parts (Filter 2). SS, T-C-BOD, and T-N in effluent were kept stable at less than 3, 5 mg/L, and 5 mgN/L, respectively, under a HRT in Filter (filter-bed) of 0.37~2.3 h. T-N at the outlet of Filter 2 were about 1~5 mgN/L under the condition of LV of 50~202 m/d. Methanol addition was controlled based on the COD/N ratio or McCarty's equation. Constant COD/N ratio control results in excess addition under large diurnal fluctuation of $NOx^--N$, and McCarty's equation can be used to add appropriate amount of methanol. Control of methanol addition by on-line nitrate measurement, control of aeration by on-line DO measurement, and control of backwashing by head loss measurement are successfully operated. These results proved that this process prove the easy-maintenance and cost-effectively treatment is attainable.

• Journal of Biomedical Engineering Research
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• v.18 no.4
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• pp.499-505
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• 1997

A non-invasive technique to measure absorption and scattering coefficients was investigated The reflected backscattered light from the surface of phantom and biological tissue was obtained by using a time-correlated single photon counting system in pico-second time domain. The absorption and scattering coefficients were acquired by the time of peak and asymptotic behavior of the time-resolved reflectance curve and agreed well the ones that is obtained with deconvolution method It was found that the approximation method was good for biological medium to calculate optical properties due to its convenience and accuracy.

• Korean Chemical Engineering Research
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• v.45 no.4
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• pp.372-377
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• 2007

In order to assess its capability as biofilter bed material under variable conditions of two parameters (inlet gas concentration and inlet gas flow rate), reticulated polyurethan was applied to remove hydrogen sulfide via a biological process. We detected a maximal elimination capacity (critical loading rate) of $488.3(330.1)g-H_2S/m^3{\cdot}hr$, when reticulated polyurethane was employed as supporting material of biofilter. This study show that the application of reticulated polyurethane carrier might be a favorable choice as a packing material in biofilter for the biological removal of hydrogen sulfide.

• Journal of the Korea Organic Resources Recycling Association
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• v.19 no.1
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• pp.57-63
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• 2011

Development of alternative energy is needed as the fossil is started to be exhausted. This alternative energy should be environmental friendly and renewable. Currently, the alternative energy which gets the most attraction is hydrogen. Hydrogen can be produced by a number of different processes. Among those methods, hydrogen production in biological way is considered as the most environmental friendly method. However, productivity of biological hydrogen production is not good enough to be commercialized yet. Thus, many researchers are trying to improve productivity and yield of biohydrogen production. Here, progress in the diverse developmental approaches on biological hydrogen production, is reviewed.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.4
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• pp.318-322
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• 2004

Lactic acid is an environmentally benign organic acid that could be used as a raw material for biodegradable plastics if it can be inexpensively produced by fermentation. Two genes (ldhL and ldhD) encoding the L-(+) and D-(-) lactate dehydrogenases (L-LDH and D-LDH) were cloned from Lactobacillus sp., RKY2, which is a lactic acid hyper-producing bacterium isolated from Kimchi. Open reading frames of ldhL for and ldhD for the L and D-LDH genes were 962 and 998 bp, respectively. Both the L(+)- and D(-)-LDH proteins showed the highest degree of homology with the L- and D-lactate dehydrogenase genes of Lactobacillus plantarum. The conserved residues in the catalytic activity and substrate binding of both LDHs were identified in both enzymes.

• Journal of Biomedical Engineering Research
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• v.38 no.6
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• pp.291-294
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• 2017

It is known that laptop computer stand is helpful to maintain the good posture while using laptop computer on the desk. But the quantitative validation of its effect has not been reported. Using the wearable neck posture tracker, the forward flexion angle of the neck can be measured in daily life. In this study, the forward flexion angles of the neck while using the laptop computer with and without laptop computer stand were compared. From the posture data of 10 subjects for 6 hours, the average of the forward flexion angle was 0.9 degree with laptop computer stand and 16.3 degree without laptop computer stand. As the conclusion, laptop computer stand can decrease the forward flexion angle which is known as forward head posture while using the laptop computer on the desk.