• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.51 no.5
• /
• pp.445-450
• /
• 2006

The nitrogen fertilization effect on growth characteristics and isoflavone content was investigated in this study, and isoflavone analyzed by HPLC with photodiode array (PDA) detector and reverse-phase $C_{18}$ column. Fertilization levels were no-fertilization, no nitrogen, 50% decreased in nitrogen, standard and 50% increased in nitrogen fertilization. The 50% increased nitrogen fertilization showed the highest growth characteristics then other fertilization level and the number of pod and seed showed maximum value 31.9 and 72.3, respectively, and seed yield was 2,460 kg/ha. During growth stages, isoflavone content in leaf, stem and root of soybean plants decreased to R5 stage then increased to R7 stage. Isoflavone content according to various nitrogen fertilization condition, in case of none fertilization, no nitrogen, 50% decreased nitrogen fertilization showed higher value than those of standard and 50% increased nitrogen fertilization levels. Aglycon content among the isoflavone isomers showed much higher in plant than in seed. The highest isoflavone content was found in the root of soybean plant parts. Isoflavone content of seed was higher in none, no nitrogen, 50% decreased nitrogen than those of standard and 50% increased nitrogen fertilization.

• The Korean Journal of Mycology
• /
• v.1 no.2
• /
• pp.1-7
• /
• 1973

Among the factors which affect the mushroom yield, this investigation was aimed to confim the relationship between nitrogen content of rice straw compost and crop yield, residual ammonia content and yield. In this investigation the nitrogen content in dry weight of compost ranged from 1.10 to 2.06% and the residual ammonia content between 0.01 and 0.8% at spawning according to the sources of organic or inorganic nitrogen and the formulas of compost materials. The results obtained are summarized as follows: 1. The relationship between nitrogen content of rice straw compost and mushroom yield was represented by the formula: y=13.95+0.048$(r=0.68^{**})$. 2. Nitrogen content and mushroom yield of compost supplemented with organic nitrogen sources were increased as compared with control or inorganic treatments. 3. The relationship between the residual ammonia content and mushroom yield is represented by the formula: $y=0.38086-0.011948+0.00012x^2(r=-0.75^{**})$. In order to obtain high cropping yield the residual ammonia content at spawning should be below 0.03% (expressed as nitrogen content). 4. Application of ammonium sulfate increased the nitrogen content of compost slightly, but the residual ammonia content was increased considerably and yield decreased. On the other hand, the residual ammonia content of urea treatment was low and increased mushroom yield remarkably.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.49 no.1
• /
• pp.41-45
• /
• 2004

We have developed and tested a new method for nondestructive estimation of chlorophyll- and nitrogen-contents in rye leaf. It was found that the relation-ships among nitrogen, chlorophyll content and fresh weight were significantly positive correlated. Nitrogen and chlorophyll content were positively correlated whereas correlation coefficients among R, G, R-B and G-B on the basis of photo-numerical values were negative. We have found that R/(R-B) obtained from data of digital camera is the best criterion to estimate the chlorophyll content of leaves. The regression curves of the relation between R/(R-B) and chlorophyll content were also calculated from the data collected on cloudy days. The coefficients of determination ($\textrm{r}^2$) were ranged from 0.33 to 0.99. In this study, the accuracy in estimating chlorophyll content from the color data of digital camera image could be improved by correcting with R, G, and B values. It is suggested that, for practical purposes, the image values estimated with sufficient accuracy using a portable digital camera can be applied for determining chlorophyll content and nitrogen status in plant leaves.

• Journal of the Korean Society of Tobacco Science
• /
• v.1 no.2
• /
• pp.120-126
• /
• 1979

The nitrogen contents of some forms in Burley tobacco leaf cultivated in Yaesan, Mokpo and Namwon district were investigated. The rate of each form in total nitrogen contents were as follows ; Protein form nitrogen 30~33 % Nitrate form nitrogen 10~123% Alkaloid form nitrogen 8~16 % Ammonia form nitrogen 6~9% Amide form nitrogen 2~ 3% Other form nitrogen 26~44 % The order of nitrate form nitrogen content on the nitrogen of each tobacco cultivated in three area was Yaesan > Namwon > Mokpo, but that of alkaloid form nitrogen was reverse order of nitrate form nitrogen. As for Quality ( grade ), the orders of alkaloid and ammonia form nitrogen content on total nitrogen were H5> 3> 1> L 1> 3> 5, but that of nitrate form nitrogen was reversed.

• Journal of Welding and Joining
• /
• v.18 no.1
• /
• pp.59-69
• /
• 2000

The purpose of the present study was to investigate weld metallurgical phenomena such as primary solidification mode, microstructural evolution and hot cracking susceptibility in nitrogen-bearing austenitic stainless steel GTA welds. Eight experimental heats varying nitrogen content from 0.007 to 0.23 wt.% were used in this study. Autogenous GTA welding was performed on weld coupons and the primary solidification mode and their microstructural characteristics were investigated from the fusion welds. Varestraint test was employed to evaluate the solidification cracking susceptibility of the heats and TCL(Total Crack Length) was used as cracking susceptibility index. The solidification mode shifted from primary ferrite to primary austenite with an increase in nitrogen content. Retained delta ferrite exhibited a variety of morphology as nitrogen content varied. The weld fusion zone exhibited duplex structure(austenite+ferrite) at nitrogen contents less than 0.10 wt.% but fully austenitic structure at nitrogen contents more than 0.20 wt.%. The weld fusion zone in alloys with about 0.15 wt.% nitrogen experienced primary austenite + primary ferrite solidification (mode AF) and contained delta ferrite less than 1% at room temperature. Regarding to solidification cracking susceptibility, the welds with fully austenitic structure exhibited high cracking susceptibility while those with duplex structure low susceptibility. The cracking susceptibility increased slowly with an increase in nitrogen content up to 0.20 wt.% but sharply as nitrogen content exceeded 0.20 wt.%, which was attributed to solidification mode shift fro primary ferrite to primary austenite single phase solidification.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.45 no.2
• /
• pp.128-133
• /
• 2000

This study was carried out to investigate the effect of forms and levels of nitrogen fertilizer on plant growth and essential oil production of Agastache rugosa. Calcium nitrate had more influenced on length and width of leaves and lateral branch length than did urea. When nitrogen fertilizer level was increased from 12 kgN/I0a to 24kgN/I0a, plant growth was stimulated and dry matter of leaf and inflorescence were increased. Top dry matter of plant with calcium nitrate treatment (38.4 g) was heavier than that of urea treatment (32.8 g). Interactions among accession and nitrogen form and nitrogen rate were not significantly different for top dry matter. The forms and rate of nitrogen fertilizer did not affect estragole content. The estragole contents was higher in leaf (91.8%) than that of inflorescence (81.3%). While the essential oil content was not affected by different nitrogen forms, nitrogen level affected the essential oil contents positively by increasing dry matter. Essential oil yield was not affected by accession or nitrogen form, but by nitrogen rate. With increasing N application from 12kgN/I0a to 24 kgN/I0a, essential oil yield was increased by 95.8 %.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.36 no.4
• /
• pp.376-384
• /
• 2023

Nitrogen-doped graphene was synthesized by a hydrothermal method using graphene oxide (GO) as the raw material, urea as the reducing agent and nitrogen as the dopant. The morphology, structure, composition and electrochemical properties of the samples are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption-desorption analysis, electrical conductivity and electrochemical tests. The results show that urea can effectively reduce GO and achieve nitrogen doping under the hydrothermal conditions. By adjusting the mass ratio of raw materials to dopants, the graphene with different nitrogen doping contents can be obtained; the nitrogen content range is from 5.28~6.08% (atomic fraction percentage).When the ratio of dopant to urea is 1:30, the nitrogen doping content reaches a maximum of 6.08%.The supercapacitor performance test shows that the nitrogen content prepared by the ratio of 6.08% is the best at 0.1 A·g^-1. The specific capacitance is 95.2 F·g^-1.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.42 no.3
• /
• pp.176-182
• /
• 2022

The aim of this study was to investigate dry matter productivity and nitrate nitrogen content in the growth stages of barnyard millet (Echinochloa esculenta) cultivated for feed, which was treated with different nitrogen fertilization levels. An early variety of barnyard millet (cv. Shirohie) was used for the test, and the different treatments with nitrogen fertilizer were as follows: 50% (N-40 kg/ha, T1), 100% (N-80 kg/ha, reference amount, T2), 150% (N-120 kg/ha, T3), 200% (N- 160 kg/ha, T4), 250% (N-200 kg/ha, T5), and 300% (N-240 kg/ha, T6). Sowing was done on May 13, 2021 and plants were harvested for four stage; vegetative stage, elongation stage, heading stage, and milk stage. The length of the millet increased significantly as the amount of nitrogen fertilization increased during the harvest period (p<0.05), but the difference was insignificant during the milk stage (p>0.05). Moreover, barnyard millet dry matter yield increased significantly as the levels of nitrogen fertilization increased (p<0.05), but there was no significant difference in dry matter yield among nitrogen fertilization levels during the heading stage (p>0.05). Chlorophyll also was significantly higher in T5 (250%) at all harvesting times, whereas nitrate nitrogen content was highest at the vegetative stage, gradually decreased as growth progressed, and lowest at the milk stage. Finally, as the nitrogen fertilization levels increased, the nitrate nitrogen content was significantly higher in all treatment groups (p<0.05). Therefore, our results suggest that the most appropriate nitrogen fertilizer levels is between 150%-200%, considering the dry matter yield, feed ingredients and nitrate nitrogen content in barnyard millet for feed.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
• /
• 2001.06a
• /
• pp.1262-1262
• /
• 2001

The rice plant is one of the important staple crops in Korea. The high yield with low cost in rice is required the soil fertility and the development of new precise method of fertilizer application by nutritional diagnosis. Now, in Korea, the nitrogen application system for the rice plant is composed of the basal fertilization, fertilization at tillering stage and fertilization at panicle stage, which the nitrogen fertilization at panicle stage amount to about 30 percent in the total amount. Thus, this experiment carried out to the development of the system that can measure the nitrogen content in the rice plant at panicle stage rapidly with the near infrared spectroscopy, and to predict the appropriate quantity of the nitrogen fertilization at panicle stage based on calibration model for test of nitrogen content in rice plant. The samples were collected from 48 varieties in 4 regions which are mainly cultivated in the southern part of Korea. And then, it collected by classifying into the leaf, the whole plant and the stem since 7 days before the nitrogen fertilization at panicle stage. The ranges of the nitrogen contents were 1.6∼4.0%, 1.7∼3.0% and 1.4∼2.7% in the leaf, the whole plant and the stem, respectively. In the calibration models created by each part of the plant under the Multiple Linear Regression(MLR) method, the calibration model for the leaf recorded the relatively high accuracy. The mutual crossing test on unknown samples were carried out using Partial Least Square(PLS) calibration model. That is, the nitrogen content in the stem was tested by calibration model made by the leaf model and that of stem was tested by calibration model made by whole plant sample. When unknown leaf sample was tested by calibration model made by all sample that collected from each part in rice plant such as leaf, stem and whole plant, it recorded the highest accuracy. As a result, to test the nitrogen content in the rice plant at panicle stage, the nitrogen content in the leaf shall be tested by the calibration model composed of the leaf, the stem and the whole plant. In future, to estimated the amount of nitrogen fertilization at panicle stage for rice plant , it will be calculated based on regression model between rice yield and nitrogen content of leaf measured by calibration model made by mixed sample including leaf, stem and whole plant.

• The Korean Journal of Food And Nutrition
• /
• v.32 no.4
• /
• pp.342-348
• /
• 2019

The objective of this study was to investigate the changes in flavor components of cheonggugjang prepared with hazelnut. Amino nitrogen content in cheonggukjang was significantly lower in the 30~40% hazelnut group compared to the control group. The volatile basic nitrogen of hazelnut added cheongkukjang showed a similar pattern to that of amino nitrogen. The number of B. subtilis was slightly increased in relation to the amount of hazelnut added, but there was no significant difference. The content of glucose increased proportionally with increasing hazelnut. Total amino acid content decreased with increasing hazelnut. The ratio of glutamic acid to total free amino acids increased with increasing hazelnut. Oleic acid content increased proportionally with increasing hazelnut, while linoleic acid content decreased. In conclusion, the addition of hazelnut may contribute to the quality diversification of cheonggukjang by changing the taste and flavor while maintaining the amino nitrogen content of cheonggukjang.