Presence Of Deuterium Research Articles

Hydrothermally Synthesized NiS2 and NiSO4(H2O)6 Nanocomposites and its Characterizations

The present manuscript discusses an in-depth explanation of the synthesis and characterization of nickel sulphide (NiS2) and nickel sulphate [NiSO4(H2O)6] nanocomposites. The phase analysis was performed through x-ray diffraction (XRD), revealing the presence of NiS2 and NiSO4(H2O)6 nanocomposites, along with the presence of deuterium. The synthesized material exhibited absorbance in the visible region, with an optimized band gap of 1.0 eV. The presence of carbon spheres was confirmed through morphological analysis performed through field emission scanning electron microscopy (FESEM), depicting the growth of NiS2 on the surface of carbon spheres and the presence of nanosheets of NiSO4(H2O)6. These techniques provide a detailed explanation of the crystallite size for the nanocomposites, their structural properties and optical properties. The material showed a narrow band gap making it highly suitable for solar cell applications.

Synthesis of Erbium Deuterides via Deuterium Ion Implantation into Erbium Thin Films

An experimental study of a synthesis technique in which deuterium ions are implanted into thin films of erbium to form erbium deuterides is presented. Results from thermal desorption spectroscopy indicate the synthesis of multiple hydride phases has occurred, including ErD3 and ErD2. The findings also indicate that, for erbium deuteride synthesis via ion beam bombardment, elevated substrate temperatures are not required to promote deuterium uptake in the film. Stoichiometries of up to ErD0.21 were achieved for a 400-nm film exposed to a 1000-eV ion beam for 5 h at a deuterium ion fluence of 3.6 × 1022 m−2. Over the tested experimental conditions, deuterium uptake was found to scale proportionally with deuterium ion fluence and ion energy. The presence of deuterium in the film was confirmed by secondary ion mass spectrometry.

Multimetallic Permethylpentalene Hydride Complexes.

The synthesis and characterization of group 4 permethylpentalene (Pn* = C8Me6) hydride complexes are explored; in all cases, multimetallic hydride clusters were obtained. Group 4 lithium metal hydride clusters were obtained when reacting the metal dihalides with hydride transfer reagents such as LiAlH4, and these species featured an unusual hexagonal bipyramidal structural motif. Only the zirconium analogue was found to undergo hydride exchange in the presence of deuterium. In contrast, a trimetallic titanium hydride cluster was isolated on reaction of the titanium dialkyl with hydrogen. This diamagnetic, mixed valence species was characterized in the solid state, as well as by solution electron paramagnetic resonance and nuclear magnetic resonance spectroscopy. The structure was further probed and corroborated by density functional theory calculations, which illustrated the formation of a metal-cluster bonding orbital responsible for the diamagnetism of the complex. These permethylpentalene hydride complexes have divergent structural motifs and reactivity in comparison with related classical cyclopentadienyl analogues.

Analysis of reactor experiments to study the transfer processes of generated tritium in lithium cps (capillary-porous system)

To date, there have been many studies on the possibility of using lithium CPS as a plasma-facing material in fusion reactors. For use such liquid-lithium systems in fusion reactors, it is necessary to determine the interaction parameters of the surface facing the plasma with the working gases under conditions simulating the real operation of the facility, i.e. under conditions of neutron and gamma radiation. Therefore, this paper is devoted to the study of the processes of hydrogen isotopes interaction with lithium CPS under reactor irradiation. The experiments presented in work were carried out at the IVG1.M research reactor by using dynamic sorption method with the presence of deuterium under the lithium CPS sample.The results of reactor experiments simulation, in particular, the distribution of tritium concentration in lithium volume and traps, and the flows of tritium released through the inner surface of the CPS into the experimental chamber at different temperatures are presented.Based on the simulation results, the following interaction parameters of tritium with lithium were determined: temperature dependences of tritium capture constant by lithium and the dissociation constant of LiT. The obtained model can be applied for analysis of tritium generation and release from different lithium-containing materials used as a filling of CPS structure (for example, lithium and tin-lithium eutectics).

Experiments and modelling of multiple sequential MeV ion irradiations and deuterium exposures in tungsten

Bulk tungsten samples were irradiated sequentially with 20 MeV tungsten ions and exposed to deuterium plasma. The experiments were performed in order to simulate the displacement damage that fusion neutrons will cause in a tungsten plasma-facing component of a future fusion device. To study the influence of the presence of hydrogen isotopes during the creation of displacement damage on the final defect density, tungsten irradiation and deuterium decoration cycles were performed up to three times. Deuterium depth profiling with 3He Nuclear Reaction Analysis and Thermal Desorption Spectroscopy showed that the deuterium concentration increased after each additional tungsten irradiation and deuterium exposure. After the third cycle, the deuterium concentration reached a maximum of 3.6 at.% at the given plasma exposure temperature of 370 K. We attribute this increase in retention to the stabilization of the displacement damage during the tungsten irradiation by the presence of deuterium. The experimental results were simulated using the MHIMS-R macroscopic rate-equation code, which was recently upgraded with a damage stabilization term to describe experiments where tungsten was irradiated with MeV tungsten ions and simultaneously exposed to low-energy deuterium ions. Using this novel model, it was possible to quantitatively describe also the present results for the sequential irradiation/exposure scheme, with model parameters that were congruent with parameters derived from the simultaneous experiment. Modelling shows that kinetic de-trapping of trapped deuterium takes place during irradiation However, it is not the dominant process that explains defect stabilization. In addition, the model facilitates the extrapolation of present experimental results to an even larger number of sequential tungsten irradiation and deuterium exposure cycles. The model predicts that after about five sequential irradiation and plasma exposure cycles, a stationary state is reached with an associated maximum trapped D concentration of 4.2 at.% for the given exposure temperature of 370 K.

Plasmon-driven carbon–fluorine (C(sp3)–F) bond activation with mechanistic insights into hot-carrier-mediated pathways

The activation of carbon–fluorine bonds is an industrially and environmentally critical, but energetically challenging, transformation. Here we demonstrate a plasmonic photocatalysis approach to visible-light-driven hydrodefluorination that utilizes aluminium–palladium antenna–reactor heterostructures. Photocatalytic hydrodefluorination of aliphatic carbon–fluorine (C(sp3)–F) bonds in fluoromethane as a model molecule, in the presence of deuterium, results in the selective production of monodeuterated methane with a remarkable photocatalytic efficiency and stability. Analysis of the reaction kinetics reveals a reduction in the apparent reaction barrier and changes to the deuterium reaction order under illumination, which suggests a non-thermal contribution from photogenerated hot carriers to the reaction pathway. Using embedded correlated wavefunction methods, the ground- and excited-state energetics and the role of plasmon excitation in lowering the reaction barrier and modifying the kinetics under illumination are determined. Plasmon-mediated carbon–fluorine bond activation represents a promising potential for applications in high-value chemical transformations, as well as in abatement technologies for the mitigation of anthropogenic polyfluoroorganic compounds. The cleavage of C–F bonds through hydrodefluorination is challenging and has been traditionally limited to unsaturated fluorocarbons. Now, a simple plasmonic approach based on the use of aluminium nanocrystal-supported palladium nanoparticles is introduced to effectively upgrade fluoromethane under visible light.

DFT Study on Interstellar PAH Molecules with Aliphatic Side Groups

Abstract Polycyclic aromatic hydrocarbon (PAH) molecules have been long adjudged to contribute to the frequently detected distinct emission features at 3.3, 6.2, 7.7, 8.6, 11.2, and 12.7 μm with weaker and blended features distributed in the 3–20 μm region. The comparatively weaker 3.4 μm emission feature has been attributed to have an aliphatic origin as carrier. PAH with an aliphatic functional group attached to it is one of the proposed potential candidate carriers for the 3.4 μm emission band, however, the assignment of carrier is still enigmatic. In this work, we employ density functional theory calculation on a symmetric and compact PAH molecule; coronene (C24H12) with aliphatic side group to investigate any spectral similarities with observed features at 3–4 μm. The side groups considered in this study are −H (hydrogenated), −CH3 (methyl), −CH2–CH3 (ethyl), and −CH=CH2 (vinyl) functional groups. Considering the possible presence of deuterium (D) in PAHs, we also include D in the aliphatic side group to study the spectral behavior. We present a detailed analysis of the IR spectra of these molecules and discuss possible astrophysical implications.

Differential adsorption of analyte and deuterated analogue onto the rotor seal of the injector in high-performance liquid chromatography/electrospray ionisation mass spectrometry.

Samples were injected onto the HPLC system via either a Valco C14W.1 internal sample injector or a Rheodyne 7125 injector, both with dissimilar Vespel rotor seals, and linked to a quadrupole time-of-flight (QTOF) mass spectrometer. Alternatively, samples were infused directly into the mass spectrometer via a syringe-driver. Electrospray ionisation in positive mode was used in both cases. Experiments demonstrated significant differential adsorption of the analyte (RAC inhibitor, NSC23766) and its tri-deuterated internal standard onto the Vespel rotor seal, with the latter seeming to be preferentially adsorbed. The deuterated analogue also showed lower electrospray sensitivity, as demonstrated by syringe infusion of a mixture of the compounds, compared with their separate infusion at the same concentration. This study has demonstrated the problem of differential adsorption onto HPLC Vespel rotor seals, and that the use of a stable-isotope-labelled analogue as internal standard does not guarantee the constancy of the analyte/internal response ratio in quantitative methods. The partial solution was to work at much higher concentration where adsorption, whilst still apparent, was relatively insignificant.

Hydrogenation of small hydrocarbons on MgO supported Pd nanoparticles: The A-E-model expanded.

The hydrogenation of ethylene and acetylene was studied on a Pdn/MgO/Mo(100) model system containing palladium particles with a narrow size distribution around Pd26 (Pd20 to Pd35). Reactivity measurements were carried out in an ultrahigh vacuum chamber under isothermal conditions in the presence of deuterium. The catalyst system can readily hydrogenate both of these small molecules, and for acetylene, an alternative reaction network exists, in which it is trimerized to benzene. Distinct deactivation behavior was found for the two molecules and ascribed to different adsorption sites formed and influenced by the carbonaceous overlayer formed during the course of the reaction. These findings extend the A-E-model by Borodziński and Gołȩbiowski to extremely small particles and low partial pressures and show that it is possible to study realistic catalytic sites under highly defined conditions.

Mathematical Modeling of Open States in Double Stranded DNA Molecule Depending on 2H/1H Ratio

The evaluation results of the possible deuterium atoms effect on the DNA base pair opening are presented in the article. The cause of these processes is the replacement of protium with deuterium atom due to the increase of energy required to break the hydrogen bond. These processes can be studied by method of mathematical modeling, with account of open states between base pairs being the key condition of the adequacy of the mathematical model of the DNA. The experiment data show that the presence of deuterium in a chain of nucleotides can cause - depending on the value of hydrogen bond disruption energy - both increase and decrease in probability of open states occurrence. For example: hydrogen bond disruption energy of 0.358·10-22n·m, non-zero probability of open states occurrence is observed in case of the absence of deuterium in the molecule, and with hydrogen bond disruption energy of 0.359·10-22n·m or more such probability equals zero. Also, when one deuterium atom is present in a molecule, non-zero probability is observed even with hydrogen bond disruption energy equal to 0.368·10-22n·m (i.e. more than 0.358·10-22n·m). Thus participation of deuterium atoms in the formation of hydrogen bonds of double helixes of a DNA molecule can cause the changes in the time required for transfer of genetic information, which can explain the effect of even minor deviations in deuterium concentration in a medium on metabolic processes in a living system.

High fusion performance in Super H-mode experiments on Alcator C-Mod and DIII-D

The ‘Super H-Mode’ regime is predicted to enable pedestal height and fusion performance substantially higher than standard H-Mode operation. This regime exists due to a bifurcation of the pedestal pressure, as a function of density, that is predicted by the EPED model to occur in strongly shaped plasmas above a critical pedestal density. Experiments on Alcator C-Mod and DIII-D have achieved access to the Super H-Mode (and Near Super H) regime, and obtained very high pedestal pressure, including the highest achieved on a tokamak (p ped ~ 80 kPa) in C-Mod experiments operating near the ITER magnetic field. DIII-D Super H experiments have demonstrated strong performance, including the highest stored energy in the present configuration of DIII-D (W ~ 2.2–3.2 MJ), while utilizing only about half of the available heating power (Pheat ~ 7–12 MW). These DIII-D experiments have obtained the highest value of peak fusion gain, QDT,equiv ~ 0.5, achieved on a medium scale (R < 2 m) tokamak. Sustained high performance operation (βN ~ 2.9, H98 ~ 1.6) has been achieved utilizing n = 3 magnetic perturbations for density and impurity control. Pedestal and global confinement has been maintained in the presence of deuterium and nitrogen gas puffing, which enables a more radiative divertor condition. A pair of simple performance metrics is developed to assess and compare regimes. Super H-Mode access is predicted for ITER and expected, based on both theoretical prediction and observed normalized performance, to allow ITER to achieve its goals (Q = 10) at Ip < 15 MA, and to potentially enable more compact, cost effective pilot plant and reactor designs.

The rate of lactate production from glucose in hearts is not altered by per-deuteration of glucose

This study was designed to determine whether perdeuterated glucose experiences a kinetic isotope effect (KIE) as glucose passes through glycolysis and is further oxidized in the tricarboxylic acid (TCA) cycle. Metabolism of deuterated glucose was investigated in two groups of perfused rat hearts. The control group was supplied with a 1:1 mixture of [U-13C6]glucose and [1,6-13C2]glucose, while the experimental group received [U-13C6,U-2H7]glucose and [1,6-13C2]glucose. Tissue extracts were analyzed by 1H, 2H and proton-decoupled 13C NMR spectroscopy. Extensive 2H-13C scalar coupling plus chemical shift isotope effects were observed in the proton-decoupled 13C NMR spectra of lactate, alanine and glutamate. A small but measureable (∼8%) difference in the rate of conversion of [U-13C6]glucose vs. [1,6-13C2]glucose to lactate, likely reflecting rates of CC bond breakage in the aldolase reaction, but conversion of [U-13C6]glucose versus [U-13C6,U-2H7]glucose to lactate did not differ. This shows that the presence of deuterium in glucose does not alter glycolytic flux. However, there were two distinct effects of deuteration on metabolism of glucose to alanine and oxidation of glucose in the TCA. First, alanine undergoes extensive exchange of methyl deuterons with solvent protons in the alanine amino transferase reaction. Second, there is a substantial kinetic isotope effect in metabolism of [U-13C6,U-2H7]glucose to alanine and glutamate. In the presence of [U-13C6,U-2H7]glucose, alanine and lactate are not in rapid exchange with the same pool of pyruvate. These studies indicate that the appearance of hyperpolarized 13C-lactate from hyperpolarized [U-13C6,U-2H7]glucose is not substantially influenced by a deuterium kinetic isotope effect.

Triton for Nuclear Fusion

In the nuclear fusion process that is permanently produced in the stars (suns) there is a thermonuclear reaction that uses as the main raw material the very first isotope of hydrogen, namely the Protium. This process is possible due to the huge temperatures and the unimaginably high pressures existing inside a star. At very high temperatures and pressures, matter begins to break even at the nuclear level. The nucleons split off and then reunited to form other types of nuclei. If it was initially thought that temperatures of tens or even hundreds of millions of degrees would be needed, today it is already proven that a minimum needed is about 40 trillion degrees. Such huge temperature is very difficult to be achieved on the Earth right now. For this reason, a compensatory solution would be the production of the nuclear fusion reaction with accelerated particles. For this reason, we want to express a major idea, namely the shift to the next hydrogen isotope, 3H, Tritium, which is much less stable compared to the first two, with its widespread use for the achievement of nuclear-merging energy, here on the Earth. We can’t achieve such temperatures yet, on earth, in safety, but especially to keep them. Only through dangerous bombs they can produce and maintain. Then the only method of achieving nuclear fusion power on the ground remains the use of particle accelerators. For this reason, modern physics power stations must look like or contain a nuclear particle accelerator. Whether we produce the cold or hot fusion reaction, we will need at least one particle accelerator. For a long time, I thought that Tokamak-type installations that have a toroidal shape represent the optimal solution for modern fusion power plants. Today, however, we doubt this, because the achieved tor has a small radius of action (the diameter of the tor is too small). But that is not the main issue that this paper proposes. In this study we want to propose the transition to experimentation of nuclear fusion energy, by exploiting (use) of tritium, namely the triton. The idea is to use triton nuclear fuel. But not the triton resulting from the presence of deuterium, but only pure triton, obtained from other methods than deuterium reactions. We propose, therefore, the elimination of deuterium as fuel and the use of Triton in its place.

O-H Activation by an Unexpected Ferryl Intermediate during Catalysis by 2-Hydroxyethylphosphonate Dioxygenase.

Activation of O–H bonds by inorganic metal-oxo complexes has been documented, but no cognate enzymatic process is known. Our mechanistic analysis of 2-hydroxyethylphosphonate dioxygenase (HEPD), which cleaves the C1–C2 bond of its substrate to afford hydroxymethylphosphonate on the biosynthetic pathway to the commercial herbicide phosphinothricin, uncovered an example of such an O–H-bond-cleavage event. Stopped-flow UV–visible absorption and freeze-quench Mössbauer experiments identified a transient iron(IV)-oxo (ferryl) complex. Maximal accumulation of the intermediate required both the presence of deuterium in the substrate and, importantly, the use of 2H2O as solvent. The ferryl complex forms and decays rapidly enough to be on the catalytic pathway. To account for these unanticipated results, a new mechanism that involves activation of an O–H bond by the ferryl complex is proposed. This mechanism accommodates all available data on the HEPD reaction.

Interaction of powerful hot plasma and fast ion streams with materials in dense plasma focus devices

A process of irradiating and ablating solid-state targets with hot plasma and fast ion streams in two Dense Plasma Focus (DPF) devices – PF-6 and PF-1000 was examined by applying a number of diagnostics of nanosecond time resolution. Materials perspective for use in chambers of the mainstream nuclear fusion facilities (mainly with inertial plasma confinement like NIF and Z-machine), intended both for the first wall and for constructions, have been irradiated in these simulators. Optical microscopy, SEM, Atomic Emission Spectroscopy, images in secondary electrons and in characteristic X-ray luminescence of different elements, and X-ray elemental analysis, gave results on damageability for a number of materials including low-activated ferritic and austenitic stainless steels, β-alloy of Ti, as well as two types of W and a composite on its base. With an increase of the number of shots irradiating the surface, its morphology changes from weakly pronounced wave-like structures or ridges to strongly developed ones. At later stages, due to the action of the secondary plasma produced near the target materials they melted, yielding both blisters and a fracturing pattern: first along the grain and then “in-between” the grains creating an intergranular net of microcracks. At the highest values of power flux densities multiple bubbles appeared. Furthermore, in this last case the cracks were developed because of microstresses at the solidification of melt. Presence of deuterium within the irradiated ferritic steel surface nanolayers is explained by capture of deuterons in lattice defects of the types of impurity atoms, pores and oxycarbonitride particles existed in the material.

Structural Transformations in Austenitic Stainless Steel Induced by Deuterium Implantation: Irradiation at 295K.

Deuterium thermal desorption spectra were investigated on the samples of austenitic steel 18Cr10NiTi pre-implanted at 295 K with deuterium ions in the dose range from 8 × 1014 to 2.7 × 1018 D/cm2. The kinetics of structural transformation development in the steel layer was traced from deuterium thermodesorption spectra as a function of deuterium concentration. Three characteristic regions with different low rates of deuterium amount desorption as the implantation dose increases were revealed: I—the linear region of low implantation doses (up to 1 × 1017 D/cm2); II—the nonlinear region of medium implantation doses (1 × 1017 to 8 × 1017 D/cm2); III—the linear region of high implantation doses (8 × 1017 to 2.7 × 1018 D/cm2). During the process of deuterium ion irradiation, the coefficient of deuterium retention in steel varies in discrete steps. Each of the discrete regions of deuterium retention coefficient variation corresponds to different implanted-matter states formed during deuterium ion implantation. The low-dose region is characterized by formation of deuterium-vacancy complexes and solid-solution phase state of deuterium in the steel. The total concentration of the accumulated deuterium in this region varies between 2.5 and 3 at.%. The medium-dose region is characterized by the radiation-induced action on the steel in the presence of deuterium with the resulting formation of the energy-stable nanosized crystalline structure of steel, having a developed network of intercrystalline boundaries. The basis for this developed network of intercrystalline boundaries is provided by the amorphous state, which manifests itself in the thermodesorption spectra as a widely temperature-scale extended region of deuterium desorption (structure formation with a varying activation energy). The total concentration of the accumulated deuterium in the region of medium implantation doses makes 7 to 8 at.%. The resulting structure shows stability against the action of deuterium ion implantation. This manifests itself in a nearly complete ceasing of deuterium accumulation from a newly implanted dose (radiation-resistant structure).

Deuterium and tritium incorporation into 5-Oxo-Pro-His-Pro-NH2 by isotope exchange

When metal catalysts of the same group are used, the nature of the inorganic support with the surface-deposited peptide becomes the crucial factor determining the yield and hydrogen isotope content of 5-oxo-Pro-His-Pro-NH2. The label distribution in the amino acid residues of 5-oxo-Pro-His-Pro-NH2 was found. The label was shown to be mainly incorporated in His. The synthesis in the presence of deuterium or tritium afforded labeled specimens containing about 3 deuterium atoms or 2.5 tritium atoms (about 70 Ci/mmol) per peptide molecule.

Visualization of water transport into soybean nodules by Tof-SIMS cryo system

This paper examined the route of water supply into soybean nodules through the new visualization technique of time of flight secondary ion mass spectrometry (Tof-SIMS) cryo system, and obtained circumstantial evidence for the water inflow route. The maximum resolution of the Tof-SIMS imaging used by this study was 1.8μm (defined as the three pixel step length), which allowed us to detect water movement at the cellular level. Deuterium-labeled water was supplied to soybean plants for 4h and the presence of deuterium in soybean nodules was analyzed by the Tof-SIMS cryo system. Deuterium ions were found only in the endodermis tissue surrounding the central cylinder in soybean nodules. Neither xylem vessels nor phloem complex itself did not indicate any deuterium accumulation. Deuterium-ion counts in the endodermis tissue were not changed by girdling treatment, which restricted water movement through the phloem complex. The results strongly indicated that nodule tissues did not receive water directly from the phloem complex, but received water through root cortex apoplastic pathway from the root axis.

Effects of deuterium oxide on formation of volatiles in linoleic acid model systems at different temperatures and oxygen limitation conditions

Effects of 30, 60, and 90 o C treatments and oxygen limitation on formation of volatiles were determined for linoleic acid model systems containing deuterium oxide (D2O) and deuterium free water. The presence of D2O accelerated consumption of headspace oxygen, indicating that the rate of lipid oxidation increased in the presence of D2O. The presence of deuterium in headspace volatiles was indirectly determined based on comparison of the amount of the fragmented mass to charge ratio (m/z) (molecular weight, Mw), which was 73.1/72.1 for d1-pentane/pentane and 125.1/124.1 for d1-2,4 octadienal/2,4 octadienal. The ratio of 73.1/72.1 (m/z) for pentane was significantly (p<0.05) higher for samples containing D2O than for samples containing deuterium free water at 30, 60, and 90 o C. Other volatiles did not follow the same pattern. 2,4-Octadienal in samples under unlimited oxygen conditions confirmed this trend, indicating that water was incorporated into volatiles during oxidation of linoleic acid under these conditions.

Investigation of iron long-term corrosion mechanisms in anoxic media using deuterium tracing

In the context of the nuclear waste storage and the preservation of metallic artefacts, the long-term corrosion of iron is studied. In an anoxic medium, the cathodic process involves the reduction of water into gaseous hydrogen and hydrogen-containing species that can precipitate with iron(II). Consequently, to understand the corrosion mechanisms, isotopic deuterium tracing (D2O) has been performed on archaeological artefacts to locate the precipitation zones in the corrosion layer. The presence of deuterium in the metallic matrix of the sample indicates that gaseous hydrogen has been formed and is a clue of the water reduction reaction. Moreover, the precipitation zones in the corrosion layer have been identified on its internal part. This is caused by the iron source location on this part of the corrosion layer. Deuterium concentration quantification made it possible to evaluate an instantaneous corrosion rate below 2μm/year.