• Journal of Bio-Environment Control
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• v.4 no.2
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• pp.152-158
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• 1995

This experiment was undertaken in order to clarify effect of NO$_3$-N/NH$_4$-N ratios(NO$_3$/NH$_4$ : 10:0, 8:2) in the nutrient solution on growth, yield, photosynthetic rate, relative concentration of chlorophyll and root activity of hydroponically grown pepper plants at three different root- zone temperatures of 18$^{\circ}C$, 22$^{\circ}C$ and 26$^{\circ}C$. Plant height, leaf number, stem diameter, fresh and dry weight of leaf and root were no effect in by three root- zone temperatures. However, leaf number, stem diameter, fresh and dry weight of leaf and stem, dry weight of root at 18$^{\circ}C$, 22$^{\circ}C$ and $25^{\circ}C$ increased when NH$_4$-N was added to the solution. Under root-Bone temperatures of 18$^{\circ}C$, 26$^{\circ}C$ condition, fruit length were longer by the addition of NH$_4$-N. Fruit number and yield increased by the addition of NH$_4$-N at three root-zone temperatures. Photosynthetic rate decreased as root - zone temperature increased. Under root-zone temperatures of 18$^{\circ}C$, 22$^{\circ}C$ and 26$^{\circ}C$ condition, photosynthetic rate increased significantly by the addition of NH$_4$-N. Chlorophyll content of plants increased at 22$^{\circ}C$. Under root-zone temperatures of 18$^{\circ}C$, 22$^{\circ}C$ and 26$^{\circ}C$ condition, chlorophyll content of plants increased by the addition of NH$_4$-N. Root activity of increased at 26$^{\circ}C$ Under root-Bone temperatures of 18$^{\circ}C$, 22$^{\circ}C$ and 26$^{\circ}C$ condition, root activity increased by the addition of NH$_4$- N.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.2
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• pp.156-163
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• 2009

Statement of problem: Recently, there have been increased esthetic needs for posterior dental restorations. The failure of posterior dental ceramic restoration are possible not only by the characters of the component materials but also by the type of food. Purpose: The research aim was to compare the in vitro fracture resistance of simulated first molar crowns fabricated using 4 dental ceramic systems, full-porcelain-occlusal-surfaced PFG, half-porcelain-occlusal-surfaced PFG, Empress 2, Ice Zirkon and selected Korean foods. Material and methods: Eighty axisymmetric crowns of each system were fabricated to fit a preparation with 1.5- to 2.0-mm occlusal reduction. The center of the occlusal surface on each of 15 specimens per ceramic system was axially loaded to fracture in a Instron 4465, and the maximum load(N) was recorded. Afterwards, selected Korean foods specimens(boiled crab, boiled chicken with bone, boiled beef rib, dried squid, dried anchovy, round candy, walnut shell) were prepared. 15 specimens per each food were placed under the Instron and the maximum fracture loads for them were recorded. The 95% confidence intervals of the characteristic failure load were compared between dental ceramic systems and Korean foods. Afterwards, on the basis of previous results, 14Hz cyclic load was applied on the 4 systems of dental ceramic restorations in MTS. The reults were analyzed by analysis of variance and Post Hoc tests. Results: 95% confidence intervals for mean of fracture load 1. full porcelain occlusal surfaced PFG Crown: 2599.3 to 2809.1 N 2. half porcelain occlusal surfaced PFG Crown: 3689.4 to 3819.8 N 3. Ice Zirkon Crown: 1501.2 to 1867.9 N 4. Empress 2 Crown: 803.2 to 1188.5 N 5. boiled crab: 294.1 to 367.9 N 6. boiled chicken with bone: 357.1 to 408.6 N 7. boiled beef rib: 4077.7 to 4356.0 N 8. dried squid: 147.5 to 190.5 N 9. dried anchovy: 35.6 to 46.5 N 10. round candy: 1900.5 to 2615.8 N 11. walnut shell: 85.7 to 373.1 N under cyclic load(14Hz) in MTS, fracture load and masticatory cycles are: 1. full porcelain occlusal surfaced PFG Crown fractured at 95% confidence intervals of 4796.8-9321.2 cycles under 2224.8 N(round candy)load, no fracture under smaller loads. 2. half porcelain occlusal surfaced PFG Crown fractured at 95% confidence intervals of 881705.1-1143565.7 cycles under 2224.8 N(round candy). no fracture under smaller loads. 3. Ice Zirkon Crown fractured at 95% confidence intervlas of 979993.0-1145773.4 cycles under 382.9 N(boiled chicken with bone). no fracture under smaller loads. 4. Empress 2 Crown fractured at 95% confidence intervals of 564.1-954.7 cycles under 382.9 N(boiled chicken with bone). no fracture under smaller loads. Conclusion: There was a significant difference in fracture resistance between experimental groups. Under single load, Korean foods than can cause fracture to the dental ceramic restorations are boiled beef rib and round candy. Even if there is no fracture under single load, cyclic dynamic load can fracture dental posterior ceramic crowns. Experimental data with 14 Hz dynamic cyclic load are obtained as follows. 1. PFG crown(full porcelain occlusion) was failed after mean 0.03 years under fracture load for round candy(2224.8 N). 2. PFG crown(half porcelain occlusion) was failed after mean 4.1 years under fracture load for round candy(2224.8 N). 3. Ice Zirkon crown was failed after mean 4.3 years under fracture load for boiled chicken with bone(382.9 N). 4. Empress 2 crown was failed after mean 0.003 years under fracture load for boiled chicken with bone(382.9 N).

• YAKHAK HOEJI
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• v.37 no.1
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• pp.49-53
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• 1993

Arylalkanoic acid derivatives are known as good non-steroidal antiinflamatory and antirheumatic agents. The new arylalkanoic acid derivatives were synthesized when 2-chloro-3-($\alpha$-cyano-$\alpha$-ethoxycarbonyl-methyl)-1, 4-naphthoquinone was reacted with some arylamines.

• Fire Science and Engineering
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• v.34 no.2
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• pp.72-85
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• 2020

This article is a study on the activity of rescue workers for designing simulation training scenarios assuming chemical accidents. On the basis of the complexity of the indoor scene in the case of chemical accidents and terrorism, we designed a 12-step simulation training scenario for two teams to analyze the improvement in firefighters' capabilities. On the basis of activity measurement in the simulation scenario, step 2 of training had the most drops in the maximum heart rate, as follow: N1, from 163 bpm to 153 bpm; N2, from 186 bpm to 151 bpm; N3, from 168 bpm to 162 bpm; and N4, from 166 bpm to 152 bpm. In terms of intensity level in the allowable activity time, it was found that in step 2 both N1 and N2 reduced from Level 5 to Level 3, N3 remained at Level 4, N4 reduced from Level 4 to Level 3, and the maximum allowable activity time increased.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.1
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• pp.31-36
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• 1993

A pot experiment was carried out to investigate the influence of application of nitrogen, phosphorus and calcium on the yield and uptake of Sr-90 by soybean plant. The results obtained were summarized as follows : 1. The application of N tended to decrease the dry matter yield of soybean. There was, however, difference in the effect on the yield between $NH_4-N$ and $NO_3-N$ ; the yield was higher in the former in the latter. On the other hand, the application of P and Ca increased the yield. 2. The uptake of Sr was decreased by the application of N, but such effect was greater in $NH_4-N$ than in $NO_3-N$. 3. The effect of N application in reducing the uptake of Sr. was enhanced by the application of P with N. 4. The combined application of P and lime showed significant effect of reducing the uptake of Sr by soybean plant. The uptake of Sr was lowest in the pot that received P, lime and $NH_4-N$ together.

• Membrane Journal
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• v.25 no.1
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• pp.27-31
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• 2015

PEBAX[poly(ether-block-amide)]-NaY zeolite composite membrane was studied on the permeability of penetrant $H_2$, $N_2$, $CO_2$ and $CH_4$ and the selectivity. When the NaY zeolite contents of PEBAX-NaY zeolite membranes were increased, the permeability of $H_2$ was increased, but the permeability of $N_2$, $CH_4$ and $CO_2$ was decreased. By the addition of NaY zeolite into PEBAX, the gas selectivity for $H_2$, $N_2$ and $CO_2$ was decreased except the increase of selectivity of $H_2/N_2$. $CO_2/N_2$, $H_2/CO_2$ and Gas/$CH_4$. The highest selectivity among these gases was from $CO_2$. In particular, the gas selectivity for $CO_2$ was the greatest with a value of 12~156.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.6
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• pp.321-327
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• 2005

Ammonia ($NH_3$) volatilization was measured from latex coated urea (LCU) and normal urea treated rice paddy under transplanting rice culture in Milyang in 2002 and 2003. The $NH_3$ volatilization from incubation experiment was significantly related with ammonium-N ($NH_4-N$) concentration and pH in the surface water. The correlation coefficients of $NH_3$ volatilization compared to the $NH_4-N$ and pH in surface water were significantly higher in urea than LCU. The $NH_3$ volatilization from both urea and LCU treatments was not increased in surface water of pH less than 8.0, while $NH_3$ volatilization increased significantly in the surface water of pH over 8.0. The results in the field experiment indicated that $NH_3$ volatilization after top-dressing of urea increased rapidly with increasing $NH_4-N$ concentration in soil and floodwater, and highest from 7 to 10 days after top-dressing. The amount of $NH_3$ volatilized from urea treatment was in the range of $4.9-8.4kg\;N\;ha^{-1}$. The variations of $NH_3$ volatilization in 2002 and 2003 were caused by changed N dynamics due to the different weather conditions such as rainfall and temperature. The amount of $NH_3$ volatilized from LCU treatment was significantly reduced compared to that of urea. The reason for the reduced $NH_3$ volatilization in LCU treatment would be due to the lower concentration of $NH_4-N$ in floodwater. The amount of $NH_3$ volatilized from LCU treated rice paddy was in the range of $1.2-1.8kg\;N\;ha^{-1}$, and the loss of N by ammonia volatilization was 2.0-2.3%. Loss of N by $NH_3$ volatilization with LCU treatment was reduced by 75-79% comparing to urea treatment.

• Journal of Life Science
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• v.25 no.5
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• pp.496-506
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• 2015

This study explored adequate water temperature ranges for maintaining stable water quality in a biofloc- based zero-water exchange culture system. Five experimental tanks with the following temperatures were set up: 10℃, 15℃, 20℃, 25℃, and 30℃. First, a biofloc-based culture system was developed in the experimental tanks; then, the tanks were stocked with goldfish and went without a water exchange for 60 days. Conditions for developing a biofloc-based culture system and stable water quality in low concentrations of inorganic nitrogen compounds at 10℃, 15℃, 20℃, 25℃, and 30℃ were maintained after 17, 26, 43, 68, and 78 days, respectively. Beginning from when the goldfish were stocked in the biofloc-based culture tanks, concentrations of $NH_4{^+}-N$ remained constant and at low levels at 10℃ and 15℃, but they showed a gradual increase at 20℃, 25℃, and 30℃. Concentrations of $NO_2{^-}-N$ and $NO_3{^-}-N$ at 10℃ and 15℃ did not remain at low levels and immediately increased. While $NO_2{^-}-N$ concentrations at above 20℃ remained constant and stable at relatively low levels, $NO_3{^-}-N$ concentrations showed a gradual increase. Conditions of 15℃ and below could not maintain low and stable concentrations of $NO_2{^-}-N$. In the pH range of 4.0 to 6.0, $NH_4{^+}-N$ concentration decreased as the pH rose. However, there was no correlation between pH and $NH_4{^+}-N$ concentration in the pH range of 6.0 to 8.0. These results indicate that pH levels should be kept at pH 6.0 and above to maintain a low and stable concentration of $NH_4{^+}-N$ at above 20℃.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.2
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• pp.230-236
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• 2008

Purpose: This study was performed to investigate the incidence, types of fracture, treatment, associated fracture and complications in patients with nasal bone fracture. Materials and methods: Clinical examination, patient's records and radiographic images were evaluated in 230 cases of nasal bone fractures who were treated at the Department of Oral and Maxillofacial Surgery, Chonnam National University Hospital for recent 5 years; from January 2002 to December 2006. Results: 1. The age of patient was ranged from 4 to 77 years (mean age=36.6 years); Males was 75.7% (n=174), and females 24.3% (n=56). 2. The cause of the nasal bone fracture in this study was a fall or slip down (28.8%, n=66), sports accident (26.0%, n=60), fighting (21.3%, n=49), traffic accident (9.6%, n=22), industrial trauma (7.8%, n=18), and the others (6.6%, n=15). 3. For the patterns of fracture, simple fracture without displacement occured in 10.4% (n=24). Simple fracture with displacement without septal bone fracture was found in 49.5% (n=114). Simple fracture with displacement in company with septal bone fracture showed in 32.6% (n=75). Commiuted fracture with severe depression was presented in 7.4% (n=17). 4. The reduction the displaced nasal bone was carried out in 2 to 10 days (mean 6.8 days) after the injury. 5. Nasal bone fracture associated with Le Fort I fracture (6.5%, n=6.5), Le Fort II fracture (7.4%, n=17), Le Fort III fracture (1.3%, n=3), NOE fracture (13.9%, n=32), ZMC fracture (17.4%, 40), maxillary bone fracture (8.3%, n=19), orbital blow-out fracture (15.7%, n=36), frontal bone fracture (1.3%, n=3) and alveolar bone fracture (10.9%, n=25). 6. The major type of treatment method was closed reduction in 90% (n=207), open reduction in 3% (n=7), and observation in 7% (n=16). 7. There were some complications such as ecchymosis, hyposmia, hypo esthesia and residual nasal deformity which are compatible. Open rhino-plasty was conducted for 3 patients who had residual nasal deformity. Conclusions: These results suggest that most of nasal bone fractures are occurred physically active aged groups(age 10-49 years) and could be treated successfully with closed reduction at 7 days after the injury.

• Journal of the Korean Mathematical Society
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• v.60 no.5
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• pp.959-986
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• 2023

Zhai and Lin recently proved that if G is an n-vertex connected 𝜃(1, 2, r + 1)-free graph, then for odd r and n ⩾ 10r, or for even r and n ⩾ 7r, one has ${\rho}(G){\leq}{\sqrt{{\lfloor}{\frac{n^2}{4}}{\rfloor}}}$, and equality holds if and only if G is $K_{{\lceil}{\frac{n}{2}}{\rceil},{\lfloor}{\frac{n}{2}}{\rfloor}}$. In this paper, for large enough n, we prove a sharp upper bound for the spectral radius in an n-vertex H-free non-bipartite graph, where H is 𝜃(1, 2, 3) or 𝜃(1, 2, 4), and we characterize all the extremal graphs. Furthermore, for n ⩾ 137, we determine the maximum number of edges in an n-vertex 𝜃(1, 2, 4)-free non-bipartite graph and characterize the unique extremal graph.