• Membrane Journal
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• v.22 no.4
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• pp.251-257
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• 2012

For the separation and recovery of n-pentane from nitrogen environment, the poly (dimethyl siloxane) (PDMS) composite membranes supported by polyetherimide (PEI) hollow fiber membranes were prepared. To characterize the gas separation properties of the resulting membranes, the permeance of n-pentane and nitrogen, concentrations of permeate and retentate, and recovery ratio were measured for n-pentane and nitrogen mixtures. The permeance of n-pentane and nitrogen, 2485.3 and 9.9 GPU, were observed respectively. As the stage cut decreases and the feed concentration increases, the n-pentane concentration in permeate tends to increase. In the meanwhile, the recovery efficiency tends to increase as the stage cut increases and the feed concentration decreases.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.10
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• pp.1438-1442
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• 2003

A method for the determination of nitrogen in ruminant feedstuffs, products and excreta (e.g. milk and urine) using a spectrophotometer is developed, where samples processed for P determination are also used to determine N. Samples are digested with sulphuric acid and subsequently with hydrogen peroxide in Kjeldahl tubes. Digested solutions along with phenol and buffered alkaline hypochlorite reagents are incubated in a water bath at $37^{\circ}C$ for 30 min and presented in the spectrophotometer. The spectrophotometer set at 625 nm measures the concentration of N of each sample. Nitrogen in 261 of the samples was also determined by the classical Kjeldahl method in order to develop a relationship between N determined by the Kjeldahl method (Y) and the colorimetric method (X). The mean value of Y was as high as that of X (0.92 vs. 0.96; p>0.05). The colorimetric method predicted Kjeldahl N highly significantly (Y=0.985X-0.024, $R^2=0.993$, p<0.001; or more simply Y=0.974X, $R^2=0.993$, p<0.001). An analysis of regression found no difference (p>0.05; both t-test and F-test) between colorimetric (0.96% N) and adjusted (0.96% N) N. In comparison with the Kjeldahl method, the analytical capacity of N by colorimetric method increases greatly, where 200-300 determinations of N are possible in a working day. In addition, the system provides an opportunity to use not only the same digested solution for both N and P determination of a particular sample, but also uses the same spectrophotometer to assay both N and P. Therefore, the system may be attractive in situations where both elements of a sample are to be determined. In conclusion, the speed of N determination, low cost, efficient use of labour, time and reagents, fewer items of equipment, and the reduction of environmental pollution by reducing effluent and toxic elements are the advantages of this method of N determination.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.5
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• pp.371-382
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• 1992

Biochemical composition, the rates of nitrogen excretion in the form of ammonia, amino acids and total nitrogen, and oxygen consumption of the shrimp Crangon affinis were measured at three temperature regimes $(7,\;15,\;and\;25^{\circ}C)$ and the variations were also determined for starvation periods (1-25 days). The composition of the major biochemical fractions was analysed into carbohydrate: $4.2\%,\;protein:\;68.6\%,\;lipid:\;7.0\%,\;chitin:\;6.3\%,\;and\;ash:\;14.6\%,$ all expressed as percentage of dry weight. Molting frequency was lower at $7^{\circ}C\;than\;25^{\circ}C$ during the period of starvation, and during the same period the higher temperature was, body weight and body compositions the more decreased. Through all starvation periods $O_2$ consumption tended to decrease but total nitrogen tended to increase at any temperature regimes. The dominant form of excreted total nitrogen was ammonia-N at any temperature. From the O:N ratio it appeared that carbohydrate and lipid reserves were quickly exhausted (1-5 days), and that proteins were the substrates oxidized to meet the energetic requirements of C. affinis at any temperature. After 25 days of starvation the O:N ratio remained constant near a value of 8, which indicates that only proteins were being utilized at three temperatures. After 25 days of starvaion C. affinis excreted 23.01ug N/mg body nitrogen per day at $7^{\circ}C,\;32.97\mu g\;N/mg$ body nitrogen per day at $15^{\circ}C,\;and\;44.81\mu g\;N/mg$ body nitrogen per day at $25^{\circ}C$, and lost about 1.75, 2.47 and $3.29^{\circ}C$ of body protein per day at 7, 15, and $25^{\circ}C$ respectively.

• Journal of Welding and Joining
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• v.5 no.4
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• pp.12-21
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• 1987

To investigate the suitability of nitrogen gas as an internal purging gas, various properties of GTA welded joints of duplex, 316L stainless steel, Cu-Ni alloy pipe using nitrogen purging gas were evaluated with reference to onew purged with argon gas. Mechanical properties evaluated by the tensile, bending test, and hardness value of welded joints with nitrogen gas purging did not show any difference those with argon gas. General and local corrosion rates of each welded joint prepared by nitrogen gas purging also showed no difference with those prepared by argon gas. Based on the present test results it is confirmed that nitrogen is a suitable purging gas for GTA welding of stainless steels and nonferrous piping systems, which can be used at lower cost instead of argon.

• Journal of Magnetics
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• v.5 no.4
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• pp.124-129
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• 2000

$Sm_2Fe_{17}N_x$ film magnets were prepared using a $Sm_2Fe_{17}$ target in a $N_2$ gas atmosphere using a Nd-YAG pulsed laser ablation technique. The effect of nitrogen pressure, deposition temperature, pulse time and film thickness on the structure and magnetic properties of $Sm_2Fe_{17}N_x$ film were studied. Increasing the nitrogen pressure up to 5 atm led to the formation of complete $Sm_2Fe_{17}N_x$ compound. Optimized magnetic properties with the nitrogenation temperature in the range 500-53$0^{\circ}C$ could be obtained by extending the nitrogenation time up to 4 hours. Relatively low coercivities of 400~600 Oe were found in $Sm_2Fe_{17}N_x$films 50~100 m thick, while a $4\piM_s$ of 10$\sim$12 kG could be achieved. In-plane anisotropy, which was the basic goal in this study, was achieved by controlling the nitrogenation parameters.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.6
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• pp.519-522
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• 2006

Randomized field experiments were conducted to study the interactive effect of sulphur (S) and nitrogen (N) on seed, oil and protein yield of two cultivars of groundnut {Arachis hypogea: cv Amber $(V_{1})$: cv Kaushal, $(V_{2})$.} Two dosage levels of sulphur ($0\;and\;20kg\;ha^{-1}$) and two dosage levels of N ($23.5\;and\;43.5kg\;ha^{-1}$) in various combinations were tested as micronutrient treatments, $T_{1},\;T_{2},\;and\;T_{3}$. Results indicated significant enhancement of the yield components namely seed and oil yield as well as seed protein. Maximum response was observed with treatment $T_{3}$(having 20kg S and 43.5kg N $ha^{-1})$. Increase in seed and oil yields of 90% and 103% in $V_{1}$, and 79 and 90% in $V_{2}$, respectively were recorded as compared to the control treatment $T_{1}$(having 0kg S and 23.5kg N $ha^{-1}$). Effect of S and N interaction was observed on protein, N and S content in seeds. The results obtained by these experiments clearly suggest that judicious balanced application of N and S could improve the yield.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1045-1050
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• 2014

$N_2O$(Nitrous Oxide) is known as the third major GHG(Green House Gas) following $CO_2$(Carbon Oxide) and $CH_4$(Methane). The GWP(Global Warming Potential) factor of $N_2O$ is 310 times as large as that of $CO_2$ because $N_2O$ in the atmosphere is very stable, and it becomes a source of secondary contamination after photo-degradation in the stratosphere. Investigation on the cause of the $N_2O$ formation have been continuously reported by several researchers on power sources with continuous combustion form, such as a boiler. However, in the diesel engine, research on $N_2O$ generation which has effected from fuel components has not been conducted. Therefore, in this research, author has investigated about $N_2O$ emission rates which was changed by nitrogen and sulfur concentration in fuel on the diesel engine. The test engine was a 4-stroke direct injection diesel engine with maximum output of 12 kW at 2600rpm, and operating condition of that was set up at a 75% load. Nitrogen and sulfur concentrations in fuel were raised by using six additives : nitrogen additives were Pyridine, Indole, Quinoline, Pyrrol and Propionitrile and sulfur additive was Di-tert-butyl-disulfide. In conclusion, diesel fuels containing nitrogen elements less than 0.5% did not affect $N_2O$ emissions in the all concentrations and kinds of the additive agent in the fuel. However, increasing of the sulfur additive in fuel increased $N_2O$ emission in exhaust gas.

• Journal of the Korean Society for Heat Treatment
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• v.22 no.2
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• pp.88-94
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• 2009

The effect of high temperature gas nitrding (HTGN) on the surface microstructure in pure Ti was investigated. Two phases of TiN and $Ti_2N$ appeared at the outmost surface, and the wide ${\alpha}$-Ti layer was formed at the next layer. On the other hand, the interior region, where the nitrogen was not permeated, exhibited ${\alpha}$'phase. The outmost surface of TiN and $Ti_2N$ showed the maximum hardness of 1000Hv, while the interior ${\alpha}$'phase was ${\sim}350$ Hv. The permeation depth of nitrogen increased with increasing the gas nitriding temperature and time. The nitrogen concentration of the surface layer seems to be over 12.7% at $1100^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2423-2430
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• 2014

Nitrogen-doped short tubular carbons (N-STCs) with big inner diameter have been successfully synthesized via carbonization of polydopamine (PDA) wrapped halloysite nanotubes (HNTs). The obtained N-STCs have average length of $0.3{\mu}m$ with big inner diameter (50 nm), thin wall (2-3 nm) and large surface area ($776m^2g^{-1}$), and show excellent electrochemical properties. As an example in electrochemical applications, N-STCs were used to electrochemically detect hydrogen peroxide ($H_2O_2$) and glucose. The results showed that the N-STCs modified glassy carbon (N-STCs/GC) electrode had much better analytical performance (lower detection limit and wider linear range) compared to the acid-treated carbon nanotubes (AO-CNTs) based GC electrode. The unique structure endows N-STCs the enhanced electrochemical performance and promising applications in electrochemical sensing.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.2
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• pp.97-101
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• 1999

No-till direct seeding cultivation of rice has major advantages such as saving of labor and cost by eliminating tillage, preparation of seed bed and trans-planting procedure compared to the conventional transplanting cultivation. A field experiment was conducted to evaluate the effects of straw treatment and nitrogen levels on the rice growth in no-till direct-seeding cultivation. Rice straw, vetch straw, and the mixture of both of the straws were mulched on the surface of soil before seeding while 4 levels of nitrogen fertilizer, 0, 7, 9, and 11 kkg/10a respectively, were applied at 3 split times, 3-weeks after sowing, 5-weeks after sowing and the panicle initiation stage. Mulching of vetch straw significantly reduced seedling establishment of rice which may be attributed to low oxidation-reduction potential of soil by vetch mulching treatment. Vetch straw increased the concentration of soil ammonium leading to an extension of the greenish leaf to panicle initiation stage. Agronomic nitrogen use efficiency (AD $E_{N}$) in heavy-mixed straw mulching plots was lower than other treatments. Grain yield and AU $E_{N}$ in the vetch treatment were less affected by fertilized N levels. Conclusively, it is suggested that heavy straw mulching was not efficient for rice seedling establishment and nitrogen usage.e.