• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.394-394
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• 2010

Ammonium ion (${NH_4}^+$) was suggested as the origin of interstellar $6.85\;{\mu}m$ band. Early study, in which organic molecule and water ice film mixtures were photolyzed so that organic acids could be produced, explained the generation of ${NH_4}^+$ from the reaction of photogenerated organic acid and ammonia ($NH_3$). However, the observed abundance of organic acids or their counter-anions are not so high in interstellar ice and not enough to protonate $NH_3$ into ${NH_4}^+$ in the observed level. Because of the shortage in photogenerated organic acids, the candidate of acid which protonates $NH_3$ should be modified. Here, we prepare $NH_3/H_2O$ binary mixtures and photolyze them with vacuum ultraviolet (VUV, peak at 10.6 and 10.0 eV). We find the ammonium ion (${NH_4}^+$) from photolyzed mixture by using low energy sputtering (LES) and reflection absorption IR spectroscopy (RAIRS). As a hydronium ($H_3O^+$) can be produced by UV irradiation and protonate bases, ${NH_4}^+$ may be formed from the reaction of photogenerated $H_3O^+$ and $NH_3$. We show the generation of ${NH_4}^+$ without any kind of organic molecules or acids, and it may explain the relatively high abundance of ${NH_4}^+$ compared to the counter-anions or organic acids in interstellar ice.

• Journal of Bio-Environment Control
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• v.5 no.2
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• pp.120-130
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• 1996

Crisphead lettuce(Lactuca sativa L.) was grown in NFT to investigate the effects of NO$_3$-N and NH$_4$-N ratio in nutrient solution and elevated $CO_2$ treatment in the crisphead lettuce growth. This experiment has been conducted under three different ratios of NO$_3$-N:NH$_4$-N(100:0, 75:25, 50:50) with two $CO_2$ concentration (control, 1500ppm ). The results are as follows; 1. In the case of not controlling pH and EC in nutrient solution, pH was gradually increased in NO$_3$-N:NH$_4$-N=100:0 treatment but rapidly decreased in the nutrient solution 2. Daily changes of NO$_3$-N and NH$_4$-N were observed without controlling the nutrient solution. In the treatments of NO$_3$-N:NH$_4$-N ratios were 75:25 and 50:50, NO$_3$-N absorption rates were 27.7% and 26.1%, while NH$_4$-N absorption rates were 87.9% and 71.2%, respectively. 3. There was little differences in total nitrogen of leaves. However phosphorus, potassium, calcium and magnesium contents were highly shown in the treatment of $CO_2$ 1500ppm and 100:0 ratio of NO$_3$-N:NH$_4$-N. 4. Higher $CO_2$ assimilation rate was shown in plants grown under $CO_2$ 1500ppm and 100:0 ratio of NO$_3$-N:NH$_4$-N. It dropped significantly with the increase of NH$_4$- N rates in nutrient solution. 5. Fresh weight, leaf number, root length and root weight of crisphead lettuce were far better in the treatment of $CO_2$ 1500ppm and 100:0 ratio of NO$_3$-N:NH$_4$-N. Growth differences by $CO_2$ elevation were not shown in other NO$_3$-N:NH$_4$-N treatments. 6. The highest nitrate contents of leaves were shown in NO$_3$-N single treatment but shown the lowest vitamin C contents. Nitrate contents of leaves were decreased by $CO_2$ but the effect was slight treatment.

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.435-436
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• 2009

In this paper, the absorption line of $NH_3$ is investigated by photoacoustic effect. And then an experiment with CO2 laser is conducted to demonstrate a method of measuring the intensity of NH3 using absorption line.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.49 no.3
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• pp.193-201
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• 2023

Hydrogen peroxide (H₂O₂) is a type of active oxygen species (ROS) that causes oxidative stress in cells and affects cell growth, proliferation, senescence, and death. The purpose of this study is to find active peptides that attenuate cytotoxicity of H₂O₂. A positional scanning synthetic tetrapeptide combinatorial library was screened to predict the sequence of potentially active peptides. As a result of comparing the effect of peptide pools on H₂O₂-induced death of human keratinocytes (HaCaT cells), various active peptide sequences were predicted. Especially, peptides containing cysteine (C) residue were predicted to be active. In follow-up experiments, the cytotoxicity and activity of cysteine-containing peptides of different lengths, such as C-NH₂, CC-NH₂, CCC-NH₂, and CCCC-NH₂ were examined. C-NH₂ and CC-NH₂ showed no significant cytotoxicity up to 1.0 mM, but CCC-NH₂, and CCCC-NH₂ showed relatively strong cytotoxicity. C-NH₂ and CC-NH₂ alleviated H₂O₂-induced cytotoxicity. CC-NH₂ was more cytoprotective compared to C-NH₂, C, N-acetyl cysteine (NAC), and glutathione (GSH). When intracellular ROS was measured by flow cytometry, H₂O₂ increased ROS production, and CC-NH₂ suppressed ROS production more effectively than C-NH₂, and it was as effective as C, NAC, and GSH. This study suggests that CC-NH₂ of the cysteine-containing peptides of different lengths has an antioxidant property that safely and effectively alleviates H₂O₂-induced cytotoxicity and ROS production.

• Applied Biological Chemistry
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• v.32 no.4
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• pp.386-392
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• 1989

The adsorption of $NH_4\;^+$ and $Zn^{2+}$ by four Korean zeolites, the major species of which are clinoptilolite, clinoptilolite with mordenite, mordenite with clinoptilolite, and mordenite was measured in different concentrations of solutions of $NH_4\;^+$ and $Zn^{2+}$, and their mixtures. The adsorption of $NH_4\;^+$ was greater than that $Zn^{2+}$ far all samples at the concentrations of the added solutions from $1\;to\;7{\times}10^{-3}N$ and this difference was greater at the higher concentrations. Also, $Zn^{2+}$ adsorption by samples was decreased by the presence of $NH_4\;^+$, but that of $NH_4\;^+$ by the presence of $Zn^{2+}$ was not. The extent of $NH_4\;^+$ selectivity among samples was increased in order of clinoptilolite with mordenite$NH_4\;^+$ adsorbed by six successive equilibrations with the solution containing both $NH_4\;^+$ and $Zn^{2+}$ each at a concentration of $3{\times}10^{-3}N$ were in range from 43.7 to 50.4 me/100g, whereas those amounts of $Zn^{2+}$ were in the range from 6.6 to 17.0 me/100g. It was suggested from these results that mordenite and clinoptilolite, particularly the former, can be used for removal of $NH_4\;^+$ from municipal wastewater and those zeolites treated with wastewater can be applied to agricultural land.

• Korean Journal of Materials Research
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• v.3 no.4
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• pp.403-409
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• 1993

In this paper, an $NH_3$, added during dry oxidation and annealing m Si( 111) is clarified effect ive to suppress or remove defects. Annealing effects in $N_2$ and $NH_3/N_2$ ambient are estimated with dry $O_2$ and $NH_4$ oxidation($NH_3$ added in dry $O_2$ oxidation) method. C;em'rated defects in dry $O_2$ oxidation are lengthened according to oxidation time. but any defects in $NH_3$ oxidation are not found. Dry oxidation, after $NH_3$ oxidation as an initial oxidation. lias the defect -removing effect at the interface of Si -$SiO_2$. After dry or $NH_3$. oxidation. the annealmg 7.5% $NH_3/N_2$ ambient brings out gettering effect of OSF. The annealing in 7.5% $NH_3/N_2$ ambient for NI L oxidation method decreaSE,s $NH_3$ length of OSF about 20 % compared with dry oxidation method. Tlw feature of OSF is pit type, the gettering is directed to (011) plane for (111) plane. and OSFs are etched following to 110) directIon.

• Horticultural Science & Technology
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• v.34 no.5
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• pp.736-745
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• 2016

This research was conducted to evaluate the impact of various pre-planting $NH_4{^+}:NO_3{^-}$ ratios on the growth of plug seedlings of 'Bool-am No.3' Chinese cabbage. With fixation of the pre-planting N concentrations to $300mg{\cdot}kg^{-1}$ in a peatmoss+coir dust+perlite (3.5:3.5:3, v/v/v) medium, the $NH_4{^+}:NO_3{^-}$ ratios were varied to 0:100, 27:73, 50:50, 73:27, 100:0. Then, the each of root media containing various ratios of $NH_4{^+}:NO_3{^-}$ as well as equal concentrations of other essential nutrients was packed into 72-cell plug trays. After seeds of 'Bool-am No.3' Chinese cabbage were sown, the seedling growths were measured 2 and 4 weeks after sowing. The weekly analysis of root media and end-crop tissue analysis for mineral nutrients 4 weeks after seed sowing were also conducted. As the seedlings grew up, the pH of the root media increased, however ECs in all treatments of $NH_4{^+}:NO_3{^-}$ ratios decreased. The concentrations of K, Ca and Mg in root media were higher in the treatments of $NH_4{^+}:NO_3{^-}$ (100:0) and $NH_4{^+}:NO_3{^-}$ (73:27) than those of $NH_4{^+}:NO_3{^-}$ (0:100) and $NH_4{^+}:NO_3{^-}$ (27:73) 2 weeks after seed sowing. But the concentrations of K, Ca, Mg and Zn were get lowered in all treatments and the differences among treatments were not significant 4 weeks after sowing. The highest $NH_4{^+}$ and lowest $NO_3{^-}$ concentrations of the root media were observed in the $NH_4{^+}:NO_3{^-}$ (100:0) among all treatments. Contrary to these, the treatment of $NH_4{^+}:NO_3{^-}$ (0:100) had the lowest $NH_4{^+}$ and highest $NO_3{^-}$ concentrations. The seedling growth in terms of fresh and dry weights of aerial part were the highest in the treatment of $NH_4{^+}:NO_3{^-}$ (23:73) at 2 weeks after sowing and those of $NH_4{^+}:NO_3{^-}$ (50:50) at 4 weeks after sowing. The survival rate of seedlings in $NH_4{^+}:NO_3{^-}$ (100:0) treatment were 19% and the growth of aerial part 4 weeks after sowing was the poorest among all treatments tested. The results mentioned above indicate that the pre-planting $NH_4{^+}$ ratio in inert media should not exceed 25% in plug stage 1 through 3 (until 2 true leaf development) and 50% in plug stage 4 (after 2 true leaves to transplant).

• Journal of the Korean Society of Tobacco Science
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• v.10 no.1
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• pp.3-9
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• 1988

Effect of several nitrogen fertilizer sources on the chlorine absorption by the burley tobacco plants was investigated under the field and pot condition. The nitrogen sources included compound fertilize.(containing 3.9% NH4-N and 6.1% NH2-N), (NH4)2SO4, NaNO3. (NH2)2CO and NH4NO3. The chlorine content of leaf during growing stage was high in (NH4)2SO4 plot , and the differences among nitrogen sources was remarkable at maximum growing stage. The chlorine content of cured leaf was high in (NH4)2SO4 plot. When the (NH4)2SO4 was applied, the total alkaloid content of cured leaf was increased and the color of cured leaf became undesirable with the increment of leaf chlorine. The yield, quality and value of cured leaf were high in NaNO3 plot , while low in (NH4)2SO4 plot.

• The Korean Journal of Ecology
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• v.21 no.6
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• pp.751-757
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• 1998

Nitrogen dynamics in mineral soils of an alder (Alnus maximowiczii) stand established on volcano Mt. Showa-Shinzan were measured by laboratory incubation method in order to clarify characteristics of $NH_{4}^{+}$ mineralization and nitrification rate, from August 1994 to July 196. Contents of total N and organic matter were relatively low, but increased in May-July. Extractable $NH_{4}^{+}$ concentrations and $NH_{4}^{+}$ mineralization were high in June and July, and decreased in midsummer and fall. Extractable $NO_{3}^{-}$ concentrations did not vary seasonally. Negative values at $NH_{4}^{+}$ mineralization and nitrification rate were observed in August and September. $NH_{4}^{+}$ mineralization was positively correlated with soil organic matter, and nitrification rates were influenced by extractable $NH_{4}^{+}$ concentration and $NH_{4}^{+}$ mineralization.

• Applied Chemistry for Engineering
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• v.7 no.3
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• pp.453-463
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• 1996

The chlorination of reagent PbS and natural ore galena with $NH_4Cl$ was investigated to find a new extraction metallurgical process of lead. The proper conditions for the chlorination of galena were that reaction temperature ; $425^{\circ}C$, $NH_4Cl$ weight ratio to galena ; 4.0 and reaction time ; 2hrs. Under these conditions, PbS was successfully chlorinated to $PbCl_2$ and the conversion was 90%. And also $NH_4Cl$ was effectively decomposed and was separated $NH_3$ and HCl. HCl was a chlorinating agent and 90% of $NH_3$ was recovered through this chlorination reaction.