• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.6
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• pp.591-598
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• 2006

The research was tried to investigate the hydrogen generation from water by the pulsed power plasma process. Hydrogen was generated by way of the electrical pulse power discharge process with the ultrasonic wave. The yield on the hydrogen generation was also studied with and without operating the ultrasonic generator, in which the applied high voltage was varied from 10 kV to 15 kV. Nitrogen and argon gases were used as working gases. As the results, the generation yield using the pure nitrogen gas is better than argon and mixed gases such as argon and nitrogen. Hydrogen concentration are significantly increased when the ultrasonic generator was operated with the electrical discharge simultaneously. It is increased with increasing the applied ultrasonic level as well.

• Korean Journal of Organic Agriculture
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• v.8 no.2
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• pp.89-96
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• 2000

To reduce loss of nitrogen and generation of ammonia gas during composting, poultry manure and sawdust were mixed at the equivalent ratio and calcium chloride, fused superphosphate and vermiculite were added. Ammonia and sulfurous gas during composting, and NH4-N and NO3-N contents of composts were periodically measured. With the treatments of 0.5∼3% calcium chloride and 3% fused superphosphate, ammonia and sulfurous gas during composting significantly decreased, and especially generation of gases sharply reduced and a increase of calcium chlorde. Extractable NH4-N content in composts treasted with calcium chloride and fused superphosphate were high but extractable NO3-N markedly decreased. In conclusion, the results suggest that it is necessary the additon of 1∼3% calcium chloride or 3% fused superphosphate to reduce loss of nirogen and generation of offensive odor during composting of poultry manure mixed with sawdust.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.6
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• pp.586-591
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• 2004

We studied the dependence of hot-tarrier-induced degradation characteristics on nitrogen concentration in NO(Nitrided-Oxide) gate of nMOS, under ac and dc stresses. The $\Delta$V$_{t}$ and $\Delta$G$_{m}$ dependence of nitrogen concentration were observed, We observed that device degradation was suppressed significantly when the nitrogen concentration in the gate was increased. Compared to $N_2$O oxynitride, NO oxynitride gate devices show a smaller sensitivity to ac stress frequency. Results suggest that the improved at-hot carrier immunity of the device with NO gate may be due to the significantly suppressed interface state generation and neutral trap generation during stress.ess.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.2
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• pp.149-154
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• 2023

In the Fourth Industrial Revolution, hydrogen energy is in the spotlight. There is a difficulty in commercialization due to the lack of hydrogen infrastructure. Therefore, a lot of hydrogen should be imported and a method using ammonia is the most useful. In this study, using the mixed gas of hydrogen and nitrogen generated when ammonia is decomposed, the hydrogen separation performance is to be tested. Hydrogen was separated using an electrochemical hydrogen compressor based on a fuel cell and the experiment was conducted by changing the ratio of hydrogen and nitrogen. In addition, the performance was also compared by the difference both the pressure and the membrane.

• Bulletin of the Korean Chemical Society
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• v.18 no.12
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• pp.1285-1288
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• 1997

The graphite tube nozzle has been developed for the generation of metastable He jet by which the nitrogen molecules initially excited in a jet with Engelking type nozzle have been further excited in a corona excited supersonic expansion. The excitation process of nitrogen molecules in the jet collision has been discussed in detail by observing the emission intensity from the vibronic emission spectra of nitrogen molecules and nitrogen molecular ions upon helium jet collision.

• Journal of Environmental Science International
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• v.5 no.4
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• pp.525-533
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• 1996

Chemical characteristics of the industrial wastewater sludge, degradation of the sludge in soil and CO2 generation and changes of nitrogen in soil treated with the sludge were investigated. The results obtained were summarized as follows: 1. Degradation rate of the sludge in soil was 26% at natural temperature, and 33% at incubation temperature at 12 weeks after treatment. 2. T-C, T-N and the C/N ratio of sludge in soil was 16.0%, 0.63% and 26, respectively, at natural temperature, and 15.0%, 0, 65% and 23, respectively, at incubation temperature at 12 weeks after treatment. 3, Camulative CO2 generation in soil treated with l%, 3% and 5% of sludge was 284, 440 and 512 mg/100 g, respectively, at natural temperature, and 440, 558 g and 654 mg/100g, respectively, at incubation temperature at 12 weeks after treatment. 4, Changes of :norganic nitrogen in soil treated with l%, 3% and 5% of sludge were 7.8, 12.8 and 16.3 mg/100g, respectively, at incubation temperature at 12 weeks after treatment. Mineralization ratio of organic nitrogen in soil treated with 1%, 3% and 5% of sludge was 10.7%, 13.6% and 15.2%, respectively, at incubation temperature at 12 weeks after treatment. 5. Chanties of pH in soil treated with 1%, 3% and 5% of Industrial wastewater sludge were in the range of 6.7~7, 5 at natural temperature, and 6.1~7.9 at incubation temperature at 12 weeks after treatment.

• Journal of Environmental Science International
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• v.17 no.10
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• pp.1069-1073
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• 2008

Indoor air quality can be affected by indoor sources, ventilation, decay and outdoor levels. Although technologies exist to measure these factors, direct measurements are often difficult. The purpose of this study was to develop an alternative method to characterize indoor environmental factors by multiple indoor and outdoor measurements. Using a mass balance model and regression analysis, penetration factor (ventilation rate divided by the sum of ventilation rate and deposition constant) and source strength factor (source strength divided by the sum of ventilation rate and deposition constant) were calculated using multiple indoor and outdoor measurements. Subsequently, the ventilation rate and $NO_2$ generation rate were estimated. Mean of ventilation rate was 1.41 ACH in houses, assuming a residential N02 deposition constant of 0.94 $hr^{-1}$. Mean generation rate of $NO_2$ was 16.5 ppbv/hr. According to house characterization, inside smoking and family number were higher $NO_2$ generation rates, and apartment was higher than single-family house. In conclusion, indoor environmental factors were effectively characterized by this method using multiple indoor and outdoor measurements.

• Journal of Korean Society for Atmospheric Environment
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• v.6 no.2
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• pp.147-154
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• 1990

A sensitive method for the determination of total selenium in aerosol particles is described. The method involves dissolution of aerosol particles by $HNO_3-HClO_4$ mixed acids, pre-reduction of Se (VI) to Se (IV) by boiling hydrochloric acid, and hydride generation followed by atomic absorption detection. Dissolved Se (IV) in 4M hydrochloric acid is reacted with $NaBH_4$ to form $H_2Se$, which is subsequently collected in an U-tube cooled in liquid nitrogen. Upon the completion of $H_2Se$ generation, the collected $H_2Se$ is rapidly vaporized into a quartz cuvette burner by removing the U-tube from liquid nitrogen, atomized, and then detected by an atomic absorption spectrophotometer. The absolute sensitivity of the method is 0.49 ng/0.0044 Abs. The accuracy of the method evaluated by analyzing standard reference materials for urban aerosol is better than 10%. Analytical results for urban and rural aerosol particles are reported.

• Applied Chemistry for Engineering
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• v.34 no.5
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• pp.507-514
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• 2023

The selective catalytic reduction (SCR) of nitrogen oxides (NO_x) was investigated in a catalyst (Ag/γ-Al₂O₃) packed dielectric barrier discharge plasma reactor. The intermittent generation of plasma in the catalyst bed partially oxidized the hydrocarbon reductant for NO_x removal to several aldehydes. Compared to using the catalyst alone, higher NO_x conversion was observed with the intermittent generation of plasma due to the formation of highly reductive aldehydes. Under the same operating conditions (temperature: 250 ℃; C/N: 8), the NO_x reduction efficiencies were 47.5%, 92%, and 96% for n-heptane, propionaldehyde, and butyraldehyde, respectively, demonstrating the high NO_x reduction capability of aldehydes. To determine the optimal condition for intermittent plasma generation, the high voltage on/off cycle was adjusted from 0.5 to 3 min. The NO_x reduction performance was compared between continuous and intermittent plasma generation on the same energy density basis. The highest NO_x reduction efficiency was achieved at 2-min high voltage on/off intervals. The reason that the intermittent plasma discharge exhibited higher NO_x reduction efficiency even at the same energy density, compared to the continuous plasma generation case, is that the intermediate products, such as aldehydes generated from hydrocarbon, were more efficiently utilized for the reduction of nitrogen oxides.

• Journal of Pharmacopuncture
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• v.5 no.2
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• pp.40-51
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• 2002

Objectives : The purpose of this study was to investigate the effect of Bee Venom on the lipopolysaccharide-induced expression phospholipase $A_2$, cyclooxygenase-2 and inducible nitrogen oxide synthase, and the generation of arachidonic acid, prostaglandin D2 and E2 in RAW 264.7 cells, a murine macrophage cell line. Methods : The expression of phospholipase $A_2$, cyclooxygenase and inducible nitrogen oxide synthase was determined by western blotting with corresponding antibodies, and the generation of arachidonic acid, prostaglandin $D_2$ and $E_2$ was assayed by ELISA method in RAW 264.7 cells. The non-toxic concentrations (0.1 to $5\;{\mu}g/ml$) of bee venom determined by MTT assay, were used in this study. Results : 1. Bee venom inhibited lipopolysaccharide-induced expression of phospholipase $A_2$ in a dose dependent manner after 48 hours treatment. 2. Bee venom inhibited lipopolysaccharide-induced expression of cyclooxygenase-2 in a dose dependent manner after 24 and 48 hours treatment. 3. Bee venom inhibited lipopolysaccharide-induced expression of inducible nitrogen oxidesynthase in a dose dependent manner after 48 hours treatment. 4. The generation of arachidonic acid, prostaglandin $D_2$ and $E_2$ was not much affected by the treatment of bee venom on the lipopolysaccharide-induced generation of arachidonic acid, prostaglandin $D_2$ and $E_2$ in RAW 264.7 cells.