• Title/Summary/Keyword: Nitrogen analysis

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A Study on the Memory Trap Analysis and Programming Characteristics of Reoxidized Nitrided Oxide (재산화 질화산화막의 기억트랩 분석과 프로그래밍 특성)

  • 남동우;안호명;한태현;서광열;이상은
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11a
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    • pp.17-20
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    • 2001
  • Nonvolatile semiconductor memory devices with reoxidized nitrided oxide(RONO) gate dielectric were fabricated, and nitrogen distribution and bonding species which contributing memory characteristics were analyzed. Also, memory characteristics of devices according to anneal temperatures were investigated. The devices were fabricated by 0.35$\mu\textrm{m}$ retrograde twin well CMOS processes. The processes could be simple by in-situ process of nitridation anneal and reoxidation. The nitrogen distribution and bonding state of gate dielectric were investigated by Dynamic Secondary Ion Mass Spectrometry(D-SIMS), Time-of-Flight Secondary ton Mass Spectrometry(ToF-SIMS), and X-ray Photoelectron Spectroscopy(XPS). Nitrogen concentrations are proportional to nitridation anneal temperatures and the more time was required to form the same reoxidized layer thickness. ToF-SIMS results show that SiON species are detected at the initial oxide interface and Si$_2$NO species near the new Si-SiO$_2$ interface that formed after reoxidation. As the anneal temperatures increased, the device showed worse retention and degradation properties. These could be said that nitrogen concentration near initial interface is limited to a certain quantity, so excess nitrogen are redistributed near the Si-SiO$_2$ interface and contributed to electron trap generation.

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High-temperature interaction of oxygen-preloaded Zr1Nb alloy with nitrogen

  • Steinbruck, Martin;Prestel, Stefen;Gerhards, Uta
    • Nuclear Engineering and Technology
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    • v.50 no.2
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    • pp.237-245
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    • 2018
  • Potential air ingress scenarios during accidents in nuclear reactors or spent fuel pools have raised the question of the influence of air, especially of nitrogen, on the oxidation of zirconium alloys, which are used as fuel cladding tubes and other structure materials. In this context, the reaction of zirconium with nitrogen-containing atmospheres and the formation of zirconium nitride play an important role in understanding the oxidation mechanism. This article presents the results of analysis of the interaction of the oxygen-preloaded niobium-bearing alloy $M5^{(R)}$ with nitrogen over a wide range of temperatures ($800-1400^{\circ}C$) and oxygen contents in the metal alloy (1-7 wt.%). A strongly increasing nitriding rate with rising oxygen content in the metal was found. The highest reaction rates were measured for the saturated ${\alpha}-Zr(O)$, as it exists at the metal-oxide interface, at $1300^{\circ}C$. The temperature maximum of the reaction rate was approximately 100 K higher than for Zircaloy-4, already investigated in a previous study. The article presents results of thermogravimetric experiments as well as posttest examinations by optical microscopy, scanning electron microscopy (SEM), and microprobe elemental analyses. Furthermore, a comparison with results obtained with Zircaloy-4 will be made.

Deriving Water Quality Criteria of Total Nitrogen for Nutrient Management in the Stream (하천에서의 영양물질 관리를 위한 총질소 환경기준 설정에 관한 연구)

  • Kim, Hak Kwan;Jeong, Han;Bae, Seung Jong
    • Journal of The Korean Society of Agricultural Engineers
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    • v.57 no.3
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    • pp.121-127
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    • 2015
  • The objective of this study is to suggest the water quality criteria of total nitrogen in order to efficiently manage the nutrient pollution in the stream. For this, correlations between water quality parameters were examined using the water quality data collected from the water quality monitoring network in the four rivers between 2003 and 2012. T-N showed positive correlations with T-P (0.636), COD (0.577), BOD (0.574), TOC (0.440), and SS (0.367). The statistical analysis including percentile analysis for the T-N and T-P concentrations was utilized to develop the water quality criteria of T-N. The feasibility of the suggested water quality criteria was evaluated by calculating the achievement rate to water quality target at the representative points in mid-watershed, then the draft water quality standard of T-N was suggested. The suggested water quality standard of T-N in the stream may be used to efficiently control the nutrient pollution in the public water body.

Automatic Titration Using Micro pH Electrode in Volatile Basic Nitrogen Analysis (마이크로 pH전극을 이용한 휘발성염기질소의 자동적정)

  • Lee, Hyeong-Choon
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.35 no.4
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    • pp.507-509
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    • 2006
  • An automatic titration was performed by a home-made automatic control system adopting a micro pH electrode as its sensing part in microdiffusion-based volatile basic nitrogen (VBN) analysis. The micro electrode was considered to be adequate for automatic VBN analysis because of its small sensor size, low immersion depth and unbreakable body. Six pork samples in different degree of freshness were analyzed both manually and automatically. The data from automatic titration were not significantly different from those taken by manual titration even at 15% significance level. The correlation coefficient was 1.000.

Preparation and characterization of boron-nitrogen coordination phenol resin/SiO2 nanocomposites

  • Gao, J.G.;Zhai, D.;Wu, W.H.
    • Advances in materials Research
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    • v.3 no.1
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    • pp.259-269
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    • 2014
  • The boron-nitrogen-containing phenol-formaldehyde resin (BNPFR)/$SiO_2$ nanocomposites (BNPFR/$SiO_2$) were synthesized in-situ, and structure of BNPFR/$SiO_2$ nanocomposites was characterized by FTIR, XRD and TEM. The loss modulus peak temperature $T_p$ of BNPFR/$SiO_2$ nanocomposites cured with different nano-$SiO_2$ content are determined by torsional braid analysis (TBA). The thermal degradation kinetics was investigated by thermogravimetric analysis (TGA). The results show that nano-$SiO_2$ particulate with about 50 nm diameter has a more uniformly distribution in the samples. The loss modulus peak temperature $T_p$ of BNPFR/$SiO_2$ nanocomposite is $214^{\circ}C$ when nano-$SiO_2$ content is 6 wt%. The start thermal degradation temperature $T_{di}$ is higher about $30^{\circ}C$ than pure BNPFR. The residual rate (%) of nanocomposites at $800^{\circ}C$ is above 40 % when nano-$SiO_2$ content is 9 %. The thermal degradation process is multistage decomposition and following first order.

Computational Analysis of Nitrogen Oxides Reduction in Exhaust Gas from Livestock Manure Solid Fuel Using Urea-based Selective Non-catalytic Reduction (우레아 기반 SNCR 적용에 따른 가축분뇨 고체연료 배기가스 NOx 저감에 대한 전산해석)

  • Donghwan Shin;Hyeongwon Lee;Junghwan Kim;Jongyoung Jo
    • New & Renewable Energy
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    • v.20 no.3
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    • pp.1-11
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    • 2024
  • Livestock manure solid fuel has been studied as a promising domestic energy resource for reducing greenhouse gas emissions in agricultural fields. To successfully commercialize this technology, the environmental facilities require optimization in accordance with domestic environmental standards. In the present study, a computational analysis model of a livestock manure solid fuel boiler system was developed using Aspen Plus® to investigate nitrogen oxides (NOx) emissions and NOx conversion efficiency using urea-based selective non-catalytic reduction (SNCR). All data were compared across different livestock species and simulated at various operating temperatures. The simulation showed that NOx emissions were the highest from chicken manure and the lowest from swine manure. However, when converted to an oxygen concentration of 12%, NOx emissions were the highest from cattle manure. Dominant factors influencing NOx emissions through a range of temperatures were analyzed, and the optimal operating temperature range (875-950℃) was derived.

Analysis of Microbial Communities in Biofilms from CSTR-Type Hollow Fiber Membrane Biofilm Reactors for Autotrophic Nitrification and Hydrogenotrophic Denitrification

  • Shin, Jung-Hun;Kim, Byung-Chun;Choi, Okkyoung;Kim, Hyunook;Sang, Byoung-In
    • Journal of Microbiology and Biotechnology
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    • v.25 no.10
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    • pp.1670-1679
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    • 2015
  • Two hollow fiber membrane biofilm reactors (HF-MBfRs) were operated for autotrophic nitrification and hydrogenotrophic denitrification for over 300 days. Oxygen and hydrogen were supplied through the hollow fiber membrane for nitrification and denitrification, respectively. During the period, the nitrogen was removed with the efficiency of 82-97% for ammonium and 87-97% for nitrate and with the nitrogen removal load of 0.09-0.26 kg NH4+-N/m3/d and 0.10-0.21 kg NO3--N/m3/d, depending on hydraulic retention time variation by the two HF-MBfRs for autotrophic nitrification and hydrogenotrophic denitrification, respectively. Biofilms were collected from diverse topological positions in the reactors, each at different nitrogen loading rates, and the microbial communities were analyzed with partial 16S rRNA gene sequences in denaturing gradient gel electrophoresis (DGGE). Detected DGGE band sequences in the reactors were correlated with nitrification or denitrification. The profile of the DGGE bands depended on the NH4+ or NO3- loading rate, but it was hard to find a major strain affecting the nitrogen removal efficiency. Nitrospira-related phylum was detected in all biofilm samples from the nitrification reactors. Paracoccus sp. and Aquaspirillum sp., which are an autohydrogenotrophic bacterium and an oligotrophic denitrifier, respectively, were observed in the denitrification reactors. The distribution of microbial communities was relatively stable at different nitrogen loading rates, and DGGE analysis based on 16S rRNA (341f /534r) could successfully detect nitrate-oxidizing and hydrogen-oxidizing bacteria but not ammonium-oxidizing bacteria in the HF-MBfRs.

Effect of $N_2$ and $O_2$ Properties of STS304 Stainless Steel Films Synthesized by Unbalanced Magnetron Sputtering Process (비대칭 마그네트론 스퍼터링법에 의해 합성된 STR304 스테인리스강 박막에서의 질소와 산소의 첨가 효가)

  • 김광석;이상율;김범석;한전건
    • Journal of the Korean institute of surface engineering
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    • v.34 no.2
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    • pp.89-96
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    • 2001
  • N- or O-doped STS304 stainless films were synthesized by an unbalanced magnetron sputtering process with various argon and reactive gas ($N_2$, $O_2$) mixtures. These films were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD), Auger electron spectroscopy (AES) and Knoop microhardness tester. The Results from X-ray diffraction (XRD) analysis showed that a STS304 stainless steel film synthesized without reactive gas using a bulk STS304 stainless steel target had a ferrite bcc structure ($\alpha$ phase), while the N-doped STS304 stainless film was consisted of a nitrogen supersaturated fcc structure, which hsa a strong ${\gamma}$(200) phase. In the O-doped films, oxide Phases ($Fe_2$$O_3$ and $Cr_2$$O_3$) were observed from the films synthesized under an excess $O_2$ flow rate of 9sccm. AES analysis showed that nitrogen content in N-doped films increased as the nitrogen flow rate increased. Approximately 43 at.%N in the N-doped film was measured using a nitrogen flow rate of 8sccm. In O-doped film, approximately 15 at.%O was detected using a $O_2$ flow rate of 12sccm. the Knoop microhardness value of N-doped film using a nitrogen flow rate of 8 sccm was measured to be approximately $H_{ k}$ 1200 and this high value could be attributed to the fine grain size and increased residual stress in the N-doped film.

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Analysis of Nationwide Soil Chemical Trait for the Application of Standard Nitrogen Level in Rice Cultivation

  • Jinseok Lee;Jong-Seo Choi;Shingu Kang;Dae-Woo Lee;Woonho Yang
    • Proceedings of the Korean Society of Crop Science Conference
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    • 2022.10a
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    • pp.121-121
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    • 2022
  • When 7 kg·10a-1, which is less than the nitrogen standard application amount of 9 kg·10a-1, is applied, the protein content is lowered and the palatibility is improved. In order to examine the applicability of nitrogen fertilization of 7 kg·10a-1 nationwide, soil samples were collected from 240 paddy fields in 8 provinces in 2021, and the organic matter content, effective phosphoric acid, and effective silicic acid were analyzed for each sample. As a result of one-way ANOVA analysis between samples collected for each province, there was no significant difference in the content of organic matter, effective phosphoric acid, and effective silicic acid except for some provinces. The contents of organic matter was higher than the appropriate level(25 ~ 30 g·kg-1) except for Gyeongsangbuk-do, the effective phosphoric acid was higher than the appropriate level(80~120 mg·kg-1) in all provinces, and the effective silicic acid was lower than the appropriate level(157 ~ 180 mg·kg-1) except for Gyeonggi-do, Jeollanam-do and Gyeongsangnam-do. As a result of analyzing the recommended fertilization amount based on the nitrogen application amount of 7 kg·10a-1, 68.3% ofthe 240 samples were able to give nitrogen fertilizer less than 7.5 kg·10a-1, and the rest had to be given more than that to satisfy the standard fertilization amount. As a result of this study, 68.3% of rice paddies nationwide can be cultivated with a standard fertilization amount of 7 kg·10a-1, however it was thought that continuous nutrient management would be required for other paddies.

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Differentiation in Nitrogen-Converting Activity and Microbial Community Structure between Granular Size Fractions in a Continuous Autotrophic Nitrogen Removal Reactor

  • Qian, Feiyue;Chen, Xi;Wang, Jianfang;Shen, Yaoliang;Gao, Junjun;Mei, Juan
    • Journal of Microbiology and Biotechnology
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    • v.27 no.10
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    • pp.1798-1807
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    • 2017
  • The differentiations in nitrogen-converting activity and microbial community structure between granular size fractions in a continuous completely autotrophic nitrogen removal over nitrite (CANON) reactor, having a superior specific nitrogen removal rate of $0.24g/(g\;VSS{\cdot}h)$, were investigated by batch tests and high-throughput pyrosequencing analysis, respectively. Results revealed that a high dissolved oxygen concentration (>1.8 mg/l) could result in efficient nitrite accumulation with small granules (0.2-0.6 mm in diameter), because aerobic ammonium-oxidizing bacteria (genus Nitrosomonas) predominated therein. Meanwhile, intermediate size granules (1.4-2.0 mm in diameter) showed the highest nitrogen removal activity of $40.4mg/(g\;VSS{\cdot}h)$ under sufficient oxygen supply, corresponding to the relative abundance ratio of aerobic to anaerobic ammonium-oxidizing bacteria (genus Candidatus Kuenenia) of 5.7. Additionally, a dual substrate competition for oxygen and nitrite would be considered as the main mechanism for repression of nitrite-oxidizing bacteria, and the few Nitrospira spp. did not remarkably affect the overall performance of the reactor. Because all the granular size fractions could accomplish the CANON process independently under oxygen limiting conditions, maintaining a diversity of granular size would facilitate the stability of the suspended growth CANON system.