Measurement of small ion beams by thermal ionisation mass spectrometry using new 10 Ohm resistors

We tested 5 newly manufactured – prototype – 10¹³ Ohm resistors in the feedback loop of Faraday cup amplifiers to measure small ion beams by Thermal Ionisation Mass Spectrometry (TIMS). The high Ohmic resistors installed in the TRITON Plus at the VU University Amsterdam theoretically have 10 times lower noise levels relative to the default 10¹¹ Ohm resistors. To investigate the precision and accuracy of analyses using these new amplifiers we measured Sr and Nd isotopes of reference standards at a range of ion currents (3.2 × 10⁻¹⁶ to 1 × 10⁻¹² A, corresponding to intensities of 32 μV to 100 mV on a default 10¹¹ Ohm amplifier) and on small amounts of material (100 and 10 pg). Internal precision and external reproducibility for Sr and Nd isotope ratios are both better when collected on 10¹³ compared 10¹² Ohm resistors and to the default 10¹¹ Ohm resistors. At an ⁸⁷Sr ion current of 3 × 10⁻¹⁴ A (3 mV on a 10¹¹ Ohm amplifier) the internal precision (2 SE) of ⁸⁷Sr/⁸⁶Sr is 5 times better for 10¹³ Ohm resistors compared to 10¹¹ Ohm resistors. The external reproducibility (2 SD) at this beam intensity is 9 times better.     

Complete dispersion analysis of single crystal neodymium gallate

A single crystal of neodymium gallate was investigated by FTIR-spectroscopy in the reststrahlen region between 100–1000 cm⁻¹. The three spectra of the crystal in principal orientations were analyzed by dispersion analysis and the dispersion parameters and the dielectric tensor function were obtained. This allows to properly characterize and quantitatively analyze films of this important substrate material by IR-optical methods.     

Three New Coordination Compounds with Neodymium Based on Tetrazole Containing Carboxylic Acid Ligands

Reactions of three tetrazole containing carboxylic acid ligands, namely, Hpztza, Htzpya, and Hpytza [Hpztza = 5‐(2‐pyrazinyl)tetrazole‐2‐acetic acid, Htzpya = 3‐(5‐tetrazolyl)pyridine‐1‐acetic acid, Hpytza = 5‐(3‐pyridyl)tetrazole‐2‐acetic acid] with NdCl₃ · 6H₂O under hydrothermal conditions, afforded the complexes [Nd(pztza)₂(H₂O)₆] · pztza · 3H₂O ( 1 ), [Nd₂(tzpya)₂(H₂O)₁₂]Cl₄ · 2H₂O ( 2 ), and [Nd(pytza)₂Cl(H₂O)₂] ( 3 ). The compounds were structurally characterized by elemental analysis, IR spectroscopy and single‐crystal X‐ray diffraction. X‐ray diffraction analyses revealed that compound 1 displays a mononuclear structure, 2 shows a dinuclear structure, and 3 features a 1D polymeric chain structure via pytza as linker. Furthermore, the luminescent properties investigated at room temperature in the solid state show that compound 2 has an obvious decrease in its luminescence, when compared to the ligand.     

Electrochemical Preparation and Characterization of Neodymium Hexacyanoferrate and Its Application

A novel route for the fabrication of neodymium hexacyanoferrate (NdHCF) modified glassy carbon electrodes (GCE) was proposed. The morphological characterization of NdHCF was examined by scanning electron microscopy (SEM) and Fourier transform infrared spectra (FTIR). The performances of the NdHCF/GCE were characterized with cyclic voltammetry and differential pulse voltammograms (DPV). The modified electrode showed excellent electrocatalytic effect and high stability toward the electrochemical oxidation of dopamine (DA) in phosphate buffer solution (pH 5.5) with a diminution of the anodic overpotential of 155 mV. The anodic peak currents increased linearly with the concentration of DA from 5.0×10^?7 to 6.0×10^?4 M with a detection limit of 1.0×10^?8 M (S/N=3). The most important is that the modified electrode could be used for the determination of DA in the presence of an ascorbic acid concentration as large as 100‐fold that of DA. The proposed method was used to determine DA in DA‐hydrochloride injection and showed excellent sensitivity and recovery. The ease of fabrication, high stability, and low cost of the modified electrode are the promising features of the proposed sensor.     

Structural,optical and dielectric relaxor properties of neodymium doped cubic perovskite (Ba1−xNd2x/3)(Zr0.3Ti0.7)O3

Neodymium doped Barium Zirconate Titanate (Ba_1−xNd_2x/3)(Zr_0.3Ti_0.7)O₃ (x = 0.00, 0.02, 0.04, 0.06, 0.08, 0.10) ceramics were prepared using the solid state reaction route. Structural characterizations of the materials were done by using X-ray diffraction and Raman spectroscopy. XRD study suggested that all the compositions were of single phase cubic perovskite structure with space group Pm-3m while Raman spectra revealed that the replacement of the Ba²⁺ ions by Nd³⁺ ions significantly reduced the intensity of the Raman active modes and shifted them towards higher energy side. Room temperature optical property was analyzed by photoluminescence spectroscopy, which confirmed formation of shallow defects in the band gap. Photoluminescence property was attributed to the presence of polar [TiO₆] distorted clusters in the globally cubic matrix. As a result PL emission spectra of these materials were found to belong to violet–blue regions. Microstructural study of sintered pellets revealed that the grain sizes increase with increase in doping concentration. The temperature dependence of the dielectric properties was investigated in the frequency range 1 kHz to 1 MHz. The broadening in the dielectric constant peak around the phase transition temperature and shifting of the temperature maximum towards higher temperatures with increase in frequency indicated a relaxor type of behavior.     

Biolabeling with nanoparticles based on Y2O3: Nd and luminescence detection in the near-infrared

Neodymium based fluorescence presents several advantages in comparison to conventional rare earth or enzyme-substrate based fluorescence emitting sources (e.g.Tb, HRP) . Based on this fact we have herein explored a Nd-based fluoroimmunoassay. We efficiently detected the presence of an oxidized low-density lipoprotein (oxLDL) in human plasma a well-known marker for cardiovascular diseases, which causes around 30% of deaths worldwide. Conventional fluoroimmunoassay uses time-resolved luminescence techniques, with detection in the visible range, to eliminate the fluorescence background from the biological specimens. By using an immunoassay based on functionalized Y₂O₃:Nd³⁺ nanoparticles, where the excitation and emission processes in the Nd³⁺ ion occur in the near-infrared (NIR) region, we have succeeded in eliminating the interferences from the biological fluorescence background, avoiding the use of time-resolved techniques. This yields higher emission intensity from the Nd³⁺-nanolabels and efficient detection of anti-oxidized low-density lipoproteins (anti-oxLDL) by Y₂O₃:Nd³⁺-antibody-antigen conjugation, leading to a novel biolabeling method.     

Investigation of Nd2CuO4 crystal structure at high pressure by neutron diffraction

Abstract

The crystal structure of Nd₂CuO₄ has been studied by neutron diffraction at pressure up to 5 Gpa. The volume compressibility value was determined as 5·6·10^?3/Gpa. The decrease of positional parameter of neodymium at high pressure has been observed. This structural change is explained by pressure induced neodymium ions charge increase.     

Development of an Electrochemical Sensor to Detect Dopamine and Ascorbic Acid Based on Neodymium (III) Oxide and Chitosan

Neodymium (III) oxide (Nd_Ox) was dispersed in chitosan dissolution and deposited on a glassy carbon electrode (chitosan‐Nd_Ox/GCE). The surface properties of the chitosan‐Nd_Ox/GCE were evaluated with FeCN₆⁻³ solution using cyclic voltammetry and electrochemical impedance spectroscopy. The modified electrode was used in the determination of individual dopamine (DP) and ascorbic acid (AA) with square wave adsorptive voltammetry. Under optimal parameters (pH 4.0; accumulation time; t_ACC 60s and accumulation potential; E_ACC 0.10 V) for DP and (pH 3,0; t_ACC 60s and; E_ACC −0.20 V) for AA, anodic peak currents were proportional to the concentration of DP and AA between 0.90 and 17.0 μmolL⁻¹, with detection limit of 0.079 μmolL⁻¹ for DP and 0.12 μmolL⁻¹ for AA. The sensor was used in the determination of DP and AA in human urine samples and vitamin C tablets with consistent results. The new sensor is easy to develop. In addition, the sensitivity in particular for AA was improved compared with previous work.     

ICP-MS法测定鼠脊髓液中超痕量镧、铈、镨和钕

采用ＮＨＯ３＋ＨＣｌＯ４混合酸溶样,感耦等离子体－质谱（ＩＣＰ－ＭＳ）直接测定鼠脊髓液中Ｌａ、Ｃｅ、Ｐｒ和Ｎｄ,对等离子体质谱测定条件进行了最佳化选择。选用铼（Ｒｅ）内标可补偿基体影响和仪器漂移。方法检出限为７．６－２０．３ｎｇ／Ｌ,加标试验回收率为９４％－１０２％,相对标准偏差（ＲＳＤ）为２．１％－３．７％。     

基于透明陶瓷材料的激光研究进展

陶瓷激光器是一种以透明陶瓷材料作为增益介质的激光器。与单晶相比,透明陶瓷具有制备周期短和烧结温度低等优势,在激活离子高掺杂浓度下能保证良好的光学均匀性,且容易制备成各种大尺寸复合结构。近年在高功率和超短超强激光输出方面得到广泛应用,产生了一系列研究成果。回顾了陶瓷激光器的发展历程,总结了透明陶瓷在高功率、超短超强脉冲激光输出和特殊波长激光输出等方面的最新进展,并阐述了基于陶瓷制备优势的新型激光材料的发展趋势。