Magnetic Faraday modulation spectroscopy of the 1–0 band of 14NO and 15NO

Magnetic rotation spectroscopy signals of the nitric oxide (NO) fundamental band near 5 μm have been observed and compared with calculated signals. This spectroscopic approach exploits magnetic field modulation in the Faraday configuration for very sensitive detection of NO. Line shapes and strengths of the Faraday signals depend on molecular parameters, like J and Ω quantum numbers of the transitions involved, and on experimental parameters, like pressure of the gas sample and applied external magnetic field strength. In this study we implemented a software model which provides a simulation of the complete v=1–0 Faraday spectrum of NO. The algorithm considers the magnetic field modulation, the collisional and Doppler broadening of the line shapes, and the line intensities of ¹⁴NO and ¹⁵NO fundamental band lines. Optimum values for pressure and magnetic field modulation for maximum sensitivity are given. Suitable spectral windows for simultaneous detection of ¹⁴NO and ¹⁵NO are discussed. Experimental data were obtained in the wavenumber region from 1840 to 1900 cm^?1 by means of a CO sideband laser and a quantum cascade laser. Comparison between calculated and observed signals shows excellent agreement.     

用14N（d，p）15N反应测定谷物种子含氮量

简述利用核技术快速无损选择高蛋白质含量谷物种子的原理和技术． The principle and technique, which the protein content in the seeds of grain was measured by using the nuclear reaction technique, was briefly described in this paper.     

High-resolution solid-state 13C14N and 13C15N heteronuclear correlation spectroscopy

Two-dimensional heteronuclear correlation spectroscopy is applied to coupled carbon and nitrogen nuclei in single crystals of amino acids and peptides. High resolution is available because the spectra have the carbon chemical shift along one frequency axis and the nitrogen chemical shift (and the second-order quadrupole shift in the case of ¹⁴N) along the second frequency axis. These two-dimensional spectra enable direct measurements of resonance frequencies and dipole-dipole couplings that are useful in providing information about the structure, dynamics, and spectral characteristics of molecules.     

用^14N（d,p）^15N反应测定谷物种子含氮量

简述利用核技术快速无损选择高蛋白质含量谷物种子的原理和技术。     

Dynamic modelling and simulation of 15N separation by chemical exchange in NO,NO2–HNO3 system

The dynamic behaviour of a ¹⁵N separation process by chemical exchange in a NO, NO₂–HNO₃ system has been analysed based on an accurate mathematical model. A nonlinear system of first-order partial differential equations was determined by considering the multiple exchange reactions between the components of the gaseous mixture and the liquid phase constituents. The mathematical model of the process describes the space–time variation of the ¹⁵N mole fraction in gas and liquid phases and provides a better understanding of operating limits and decision support in process design and optimisation.     

气体NO/N2系统等离子体反应NO还原机理研究

首先建立了气体放电等离子体发射光谱测量系统,获得了NO/N2和纯N2气体放电的发射光谱,然后用自洽场分子轨道从头计算法得到了N2基态和激发态分子轨道模型.发现NO/N2气体放电等离子体脱除NO主要是通过包括反应速度非常快的N+NO→N2+O以及e+N2(A3∑u+)→2N+e和e+N2→N2(A3∑u+)+e在内的一系列基元反应进行的,活性N原子是NO还原的基础.     

15N16O的激光磁共振谱与同位素分子15N17O和15N18O的光谱分析

采用内腔式饱和吸收技术获得 Ｌａｍ ｂ 凹陷,使 Ｃ Ｏ 激光磁共振谱仪的灵敏度及分辨率大大提高．利用该技术对自然丰度下１５ Ｎ １６ Ｏ 的 Ｘ２Π（ υ＝ １） ← Ｘ２Π（ υ＝ ０） 塞曼跃迁进行测量,实现了包括Λ双分裂在内的各种精细结构的谱分辨．结合已发表的１５ Ｎ Ｏ 同位素分子光谱实验数据进行分析计算,拟合得到迄今最完备、最精确的各相关同位素分子１５ Ｎ ｍ Ｏ（ ｍ ＝ １６ —１８）的结构参数．     

15N-Markierung von Plasmaaminosäuren nach oraler Applikation von [15N]Glycin, [15N]Leucin und [15N]Hefeprotein-Thermitase-Hydrolysat

For the biosynthetic preparation of ¹⁴C-erucic acid (C₂₁H₄₁COOH) by means of rape plants cv. sollux the plants were supplied with ¹⁴CO₂ and additionally fed with ¹⁴C-Sodium acetate after anthesis. After saponification of the extracted lipids the erucic acid was isolated and purified. The substance was identified by gas chromatography. The incorporation of the applied radioactivity (34 MBq ¹⁴CO₂; 37 MBq¹⁴C-natrium acetate) into the fatty acids amounted to 1,2 per cent. The eruric acid could be isolated from the fatty acids mixture with a specific radioactivity of 1,001 MBq/mmol and a purity of 97,2 per cent.     

[15N]Methacetin-und [15N]Ammoniumtest zur Leberfunktionsprüfung im Kindesalter

The stable isotope content of samples of precipitation and of the river water throughout the Piracicaba basin in Brazil was measured over a two-year period. The isotope values of precipitation follow a consistent pattern of relatively depleted values of both deuterium and oxygen 18 during the rainy summers and enriched ones during the dry winters, with all values aligned slightly above the Global Meteoric Water Line. The isotopic composition of the river water throughout the basin shows a remarkable spatial coherence and much smaller scatter of data than those of the precipitation. The isotope composition of river water is close to that of the precipitation in the rainy season, however, with a consistent lower d-excess value by 1‰–2‰. This is attributed to evaporative water loss in the basin, in part an expression of the recycling of water due to the anthropogenic activity in the region. The more divergent values are recorded during high-water stages in the rivers. In many cases, the floods during the beginning of the rainy season are characterized by an enrichment of the heavy isotopes and lower d-excess values when compared to the precipitation, with the opposite situation later in the rainy season. This is interpreted as resulting from the watershed/riverflow interaction pattern, and it thus suggests that the isotope composition can monitor the hydrologic situation in the basin and its changes.     

水溶液中组氨酸的14N NMR研究

用NMK法测得不同pH值条件下组氨酸的¹⁴N谱,用反转恢复法测得¹⁴N的T1值。根据¹⁴N谱及T₁值快速且准确地证实了组氨酸在不同电离情况下的结构。     

SHA+脉冲序列用于g-C3N4样品15N-15N相关性的固体核磁共振研究

利用固体核磁共振实验研究了15N标记的g-C3N4样品中的15N-15N空间相关性,在高场和魔角旋转条件下对比两种不同的脉冲序列PDSD和SHA+的实验效果。发现当某个氮上连有质子的时候,脉冲序列SHA+比PDSD可以更好地检测15N原子间的极化转移。该研究可以为材料科学领域,特别是含氮掺杂的碳材料,提供一种有价值的研究方法。     

O(1D)+N2O→NO+NO反应的理论研究

应用三体模型及扩展的LEPS势能面(PES),对初始条件为(Ecol=55 kJ/mol,v=0,j=0)的O(1D)+N2O→NO+NO反应体系进行了准经典轨线(QCT)计算.根据计算结果对体系的势能面及反应机理进行详细的分析和讨论,较全面地研究了此反应体系的动力学特征.     

Untersuchungen mit 15N im Dauerdüngungsfeldversuch

Abstract

Long-term static fertilizer experiments are important for the soil fertility research, particular for using nitrogen problems. There are several possibilities for ¹⁵N-traces in such experiments. One example is the International Organic Nitrogen Long-Term Experiment at Berlin-Dahlem in which ¹⁵N-tracers are used, involving organic and inorganic fertilizers. By analyzing the soil and the plant biomass, it was possible to distinguish between nitrogen originating from the soil and that from the fertilizer. Some results are published.     

同位素~(15)N光电光谱分析

氮在自然界中有两种稳定性同位素,~(14)N(99.635%)和~(15)N(0.365%)。由于同位素~(15)N具有非放射性的特点,已被广泛用作标记原子,进行农业、土壤、生物、医学等过程研究。在各种同位素~(15)N分析方法中,光谱法由于仪器简单,操作方便,灵敏度和准确度较高,已成为一种广泛应用的重要方法,并生产了专门分析仪器。     

Использование изотопа N15 в изученпи усвояемости азотньіх минеральньіх удобрений

The effect of contamination of a cyanide, phosphate-buffered gold-plating bath with iron, cobalt, or nickel on the codeposition of these metals with gold, was investigated using ⁵⁹Fe, ⁵⁸Co and ⁶³Ni. It was shown that cobalt and nickel were practically not codeposited in gold if present in the solution in amounts up to 1000 or 2000 mg/dm³ respectively. Iron deposited in high amounts (up to 18%) depending on its concentration and the cathode current density. The diminishing in current efficiency of the plating process is proposed as an early signal of the contamination of gold deposit with iron.     

14N遥测核四极共振中的偏离共振效应

本文对遥测NQR谱中的偏离共振效应作了较详细地研究,发现¹⁴N谱线的强度随偏离共振效应而变化。当偏离共振强度与射频场强度接近时,测得的谱线强度最大。该效应可用来增强¹⁴N遥测NQR谱仪的灵敏度。上述实验现象在理论上采用脉冲的激发带宽方法作了解释和讨论。     

带微处理器的再生式14N NQR谱仪

本文介绍一种用场效应管制成的限幅再生式¹⁴N NQR谱仪。这种谱仪的频率范围为(1-5) MHz,射频幅度(0.5-4) V_P-P,为了获得数字记录的NQR谱线,利用微处理器Z-80构成的数字相敏检波系统,把数字相敏检波系统接至信号处理通道,就构成一台带有微处理器的¹⁴N NQR谱仪。用它测定了乌洛托品(HMT)、亚硝酸钠和对位澳代苯胺等十多个含氯化合物在室温与77K时的¹⁴N NQR谱线。实验结果表明,用微处理器控制的NQR谱仪的信噪比是一般谱仪的两倍。此外,这种仪器也为进一步数据处理提供方便。     

Bestimmung der 15N Häufigkeit bei nichtstatistischer 15N-verteilung in N2 sowie bei N2O in Bodenluftproben mittels GC-R-IRMS-Kopplung in einem Probenlauf

Abstract

An analysis technique based on GC-R-IRMS coupling (Gas-Chromatography-Reduction-Isotope Ratio Mass Spectrometry) is demonstrated. The ¹⁵N abundance of N² and N²O in atmospheric air or soil atmosphere from nitrification or denitrification processes with nonrandom distribution is determined in one run. The 12 ml sample is separated from CO² and transported by a helium gas stream through a cooling trap. The N²O is trapped in the cooling trap while the N² passes through it and enters the GC. After GC separation and O² removal in a reduction column, part of the N² enters an isotope mass spectrometer to determine the masses m/z 28,29 and 30. The interferences on mass 30 by the formation of NO in the ion source of the mass spectrometer are eliminated by a calibration and a correction procedure. Upon removing the cooling trap, the N²O is injected into the GC, where it is separated and then quantitatively reduced to N² in a reduction column. The measurement of one sample takes 16 minutes. The detection limit of the ³⁰R_t in alteration N₂ is Δ³⁰R_t = 5 · 10^?7. The detection limit of the N₂O is 3.6 nl.