Properties Of Th Research Articles

Thermal Expansion and Elastic Properties of Th–6U–4Zr Alloy

Thermal Expansion and Elastic Properties of Th–6U–4Zr Alloy

Reaction 55Mn + 159Tb : preparation for the synthesis of new elements* *Supported by the Strategic Priority Research Program of Chinese Academy of Sciences (XDB34010000), the Guangdong Major Project of Basic and Applied Basic Research (2021B0301030006), the National Key R&D Program of China (2018YFA0404402), the CAS Project for Young Scientists in Basic Research (YSBR-002), the Youth Innovation Promotion Association CAS

The complete fusion reaction of Mn + Tb was studied on the gas-filled recoil separator SHANS2. Nineteen ER - α - α decay chains from Th produced from the 4n evaporation channel were observed. The α-particle energy and half-life of Th were determined as 7922(14) keV and 14(4) ms, respectively. In addition, the decay properties of = 7788(14) keV and = 36 ms were obtained for Th. The measured α decay properties of Th and Th were consistent with literature data. The cross sections were measured to be 0.59 nb and 0.19 nb for Th and Th, respectively. The equilibrium charge state of the recoiled nucleus Th was determined experimentally. The new data were helpful for estimating the equilibrium charge states of elements 119 and 120, which could be produced via the Pu(Mn, 3n)119 and Am(Mn, 3n)120 reactions, respectively.

Synthesis and characterization of graphene oxide/alginate and application of central composite design in the adsorption of Th(IV) on the nanobiocomposites

Abstract In this study, graphene oxide and aginate were used to synthesis of nanobiocomposites under different synthesis conditions and the used to investigate the adsorption properties of Th (IV) ions from aqueous solutions. BET surface area, SEM and TEM images, FT-IR spectrometry, XRD techniques were used for the characterization of the adsorbents. In batch adsorption experiments, parameters affecting the adsorption efficiency such as solution pH, contact time, Th (IV) concentration and temperature were investigated using central composite design (CCD). ANOVA (analysis) analysis at the 95% confidence interval of the model applied for the experimental design and the compatibility of this model with the experimental findings were examined. The relevance of the model for the nanobiocomposite prepared by the 1st method is that the P value is <0.05 and the model F value is 23.77 and 39.45 with the 2nd method, respectively. These results show that the regression for this method is statistically high. The correlation coefficient (R 2), which was 95.69% for the 1st method and 97.36% for the 2nd method, indicates a high coordination between the observed values and the estimated values. According to the CCD results, it has been observed that the main effects of the adsorption process with the materials obtained by the 1st method are in the direction of increasing the concentration, while pH, time and temperature do not have a statistically significant effect. In the adsorption process with the materials obtained by the 2nd method, it was observed that the concentration, time and temperature caused an increasing effect. Langmuir, Freundlich and Dubinin–Radushkevich isotherms were used to determine the adsorption model and the constants related to these isotherms were calculated. In addition, the adsorption process was also investigated in terms of thermodynamics.

Charge Properties of Thorium Implanted in Silicon Oxide

A study of thorium atoms implanted in silicon oxide was carried out within the density functional theory method. The charge properties of Th in the ThO2:nSiO2 and Th:nSiO2 compounds, where Th acts as an interstitial and substitutional impurity in cristobalite, have been studied. Geometric optimization of structures is carried out with allowance for electron-electron interactions, self-consistent distribution of electron density is investigated, and Bader effective charges are estimated.

DFT calculation of 229thorium-doped magnesium fluoride for nuclear laser spectroscopy

The 229thorium nucleus has an extremely low-energy isomeric state that could be manipulated with light in the vacuum ultraviolet (VUV) range. Recent measurements based on internal conversion electrons place the isomer energy at 8.28(17) eV (Seiferle B et al 2019), within the transmission window of large-band-gap materials, such as fluoride single crystals. Doping 229Th into VUV-transparent materials realizes a spectroscopy target with a high nuclei density and might form the basis of a solid-state nuclear clock. This paper presents a theoretical study of the optical properties of a thorium-doped MgF2 crystal. Using the Vienna Ab-initio Simulation Package, we perform density functional theory calculations of the electronic and optical properties of Th:MgF2. We determine whether thorium will be accepted as a dopant and identify the charge compensation mechanism and geometry. The simulations indicate, that the band gap of Th-doped MgF2 will be significantly reduced compared to undoped MgF2, below the expected 229Th isomer energy. This result is in striking contrast to a similar study performed for Th-doped CaF2 (Dessovic P et al 2014 J. Phys. Condens. Matter 26 105402).

Культивари виду Thuja plicata Donn ex D. Don у Правобережному Лісостепу України та можливості їх використання в садово-парковому будівництві

Досліджено внутрішньовидове різноманіття виду Thuja plicata Donn ex D. Don у Правобережному Лісостепу України. Встановлено, що із 54 відомих культиварів виду в дендрологічних парках регіону вже багато років успішно зростають два: Th. p. 'Zebrina' і Th. p. 'Aureovariegata'. За останні 10 років також були введені Th. p. 'Dura' та Th. p. 'Whipcord'. У декоративному садівництві поширені такі культивари Th. plicаta: Th. p. 'Atrovirens', Th. p. 'Aureovariegata', Th. p. 'Can-Can', Th. p. 'Daniellow', Th. p. 'Dura', Th. p. 'Excelsa', Th. p. 'Gelderland', Th. p. 'Goldy', Th. p. 'Kornik', Th. p. 'Whipcord', Th. p. 'Zebrina' та Th. p. 'Zebrina Extra Gold'. Для характеристики різноманіття культиварів Th. plicаta, що ростуть у Правобережному Лісостепу України, використано систему класифікації формового складу поліваріантних видів Р. В. Кармазіна. Згідно з цією класифікацією, досліджувані рослини Th. plicаta належать до надгрупи В (рослини з лускоподібною хвоєю). Із 12 культиварів до групи І віднесено шість; до групи ІІ – три; до групи ІІІ – три. Визначено біометричні показники досліджуваних культиварів. Виділено культивари Th. plicаta, які поширені в районі досліджень за найбільш істотними декоративними ознаками, а саме: за забарвленням хвої, формою крони та висотою (низькорослі форми). Враховуючи їхні декоративні якості, надано рекомендації щодо застосування у різних типах насаджень: солітерах, групах, алеях, живоплотах, під час створення альпінаріїв та контрастних композицій.

Study on Th(IV) Adsorption Properties on Natural and Surface-Modified Red Soil

In order to study the effects of inorganic and organic modification on the adsorption properties of red soil (RS), ferric chloride (FC) and hexadecyl trimethyl ammonium bromide (HTAB) surface-modified red soil have been prepared and characterized by SEM, FT-IR and X-ray diffraction. Adsorption properties of Th(IV) on natural red soil (NRS), FC surface-modified red soil (FC-RS), and HTAB surface-modified red soil (HTAB-RS) have been investigated by batch technique. The inorganic and organic modification have been found to greatly improve the adsorption kinetics and thermodynamic properties and increase the adsorption capacity as compared with NRS. The adsorption of Th(IV) on the three adsorbents have been strongly dependent on pH and ionic strength, and intra-particle diffusion was the rate-controlling step. The non-linear pseudo-second-order kinetic model could fit the kinetics much better compared with the linear forms, and the linear and non-linear Langmuir expressions could fit the thermodynamics. The results obtained denote on successful application of inorganic and organic modification to treatment of water samples spiked to Th(IV) ions.

Electrochemical behavior of Th(IV) on the bismuth electrode in LiCl–KCl eutectic

The electrochemical behavior of Th(IV) on a bismuth electrode in LiCl–KCl eutectic was investigated by various electrochemical techniques, aiming at in-depth elucidation of basic electrochemical and thermodynamic properties of Th in molten salt. The results of cyclic voltammetry and coulometric titration indicated that the reduction of Th(IV) on a liquid Bi electrode occurred at −0.92 V (vs. Ag/AgCl) and was a one-step process with four electrons transferred. In addition, thermodynamic properties of Th in liquid Bi medium were evaluated by coulometric titration method in the temperature range from 723 to 798 K. The redox peaks of Bi2Th intermetallic compound were detected at −1.13 and −1.05 V, and the corresponding Gibbs free energy of formation was measured by open circuit chronopotentiometry (OCP). Finally, galvanostatic electrolysis (GE) was conducted on a liquid Bi electrode to extract Th from molten salt at 773 K. X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive spectrometry (SEM-EDS) were applied to characterize the composition and morphology of the products, and revealed the formation of Bi2Th intermetallic compound.

Encapsulation of Thymol in cyclodextrin nano-cavities: A multi spectroscopic and theoretical study.

Cyclodextrins have a wide range of applications in different areas of drug delivery and pharmaceutical industry due to their complexation ability and other versatile characteristics. Here we have studied the binding interactions of a small biologically important phenolic molecule, Thymol (Th), with both α and β cyclodextrins (CDs), which are well known drug delivery vehicles. Extent of encapsulation has been determined using several spectroscopic techniques. In fluorescence experiments, significant increase in fluorescence intensities have been discerned for both the CDs but there had been a much early saturation for αCD. Anisotropy experiments have been performed too and very surprisingly no appreciable increase in anisotropy value was observed in either case. Isothermal titration calorimetry (ITC) data, however, show signature of binding of Th with the βCD. These intriguing results were explained with the help of molecular docking and dynamics simulation studies. The docking calculations have shown that Th goes inside both α and βCD. In keeping with the final NMR data and molecular dynamics we have ultimately concluded that solvated Th molecules are the main participants in the interaction with CDs which is responsible for these intriguing behaviors. Finally we have also performed an antioxidant assay to reveal the practical application of such encapsulation. It has been found that on encapsulation there is an enhancement of the antioxidant behavior of Th. Then we have also performed an antibacterial assay to show the unchanged antibacterial properties of Th on encapsulation. Hence it can be deduced that Th can be safely delivered through CDs in living system without hampering its beneficial properties.

Pressureless densification, microstructure tailoring and properties of Ta0.8Hf0.2C-based composites

Ta0.8Hf0.2C (TH) ceramics are desirable for applications in ultra-high temperature environments, but they are difficult to be sintered pressurelessly. TH ceramics were densified up to 98.8% from commercial powders via pressureless sintering (PLS) at 2473K. SiC was introduced as secondary phase to tailor microstructures and improve properties of TH. The influence of SiC volume fraction on the densification, microstructure evolution and room-temperature properties of TH-based ceramics were examined. Average grain size of TH was refined from 13.6 down to 2.0μm. 10vol% SiC addition contributed to densification of Ta0.8Hf0.2C-SiC (THS) composites with a relative density of 99.6%. The mechanical properties of THS were fairly good, and thermal properties of sintered THS displayed a remarkable improvement compared with TH: the coefficient of thermal expansion (CTE) showed a reduction of 8.6% while the thermal conductivity increased from 18.6 to 41.5W/mK.

Neostability in countable homogeneous metric spaces

Given a countable, totally ordered commutative monoid R=(R,⊕,≤,0), with least element 0, there is a countable, universal and ultrahomogeneous metric space UR with distances in R. We refer to this space as the R-Urysohn space, and consider the theory of UR in a binary relational language of distance inequalities. This setting encompasses many classical structures of varying model theoretic complexity, including the rational Urysohn space, the free nth roots of the complete graph (e.g. the random graph when n=2), and theories of refining equivalence relations (viewed as ultrametric spaces). We characterize model theoretic properties of Th(UR) by algebraic properties of R, many of which are first-order in the language of ordered monoids. This includes stability, simplicity, and Shelah's SOPn-hierarchy. Using the submonoid of idempotents in R, we also characterize superstability, supersimplicity, and weak elimination of imaginaries. Finally, we give necessary conditions for elimination of hyperimaginaries, which further develops previous work of Casanovas and Wagner.

Process for the separation of thorium and rare earth elements from radioactive waste residues using Cyanex® 572 as a new extractant

In this paper, a process for the separation of thorium (Th) and rare earth elements (REEs) from radioactive waste residues of ion-absorbed type rare earth minerals using Cyanex® 572 (C572) as a new extractant has been developed. The extraction and stripping properties of Th and REEs with Cyanex® 572 were studied systematically. The separation factor of Th to Lu, βTh/Lu, are higher than 80 and 1.46×103, when the equilibrium HCl concentration is larger than 0.3 and 1.0mol/L, respectively. The separation selectivity of Th and REEs showed good performance in the extraction system consisting of C572 and isooctanol in 260# kerosene with the βTh/ΣREEs value of 4.38×104. The leaching rates of Th and REEs from the roasted waste residues by HCl were found to be 69.6% and 92.1%, respectively. Recovery of Th and REEs can be achieved by total 10 stages of extraction, scrubbing and stripping section.

Computational insight into complex structures of thorium coordination with N, N'- bis(3-allyl salicylidene)-o-phenylenediamine.

Theoretical calculations on the structure of Th(IV) complex containing N, N'- bis(3-allyl salicylidene)-o-phenylenediamine (BASPDA) were performed using density functional theory (DFT) at the B3LYP/6-311G** level. The geometrical structural parameters and infrared spectra results of the Th(BASPDA)2 from the calculation were compared with the parallel dislocated structure (PDS) obtained in laboratory. The calculated structural parameters were in good agreement with the experimental results. In addition, based on the calculations, a stereoisomer SFS (staggered finger " + " structure) of the Th(BASPDA)2 complex was forecasted by the analysis of a comprehensive method. The charge distribution, structural parameters, bond order indices, spectral properties and thermodynamic properties as well as the molecular orbitals of the two possible crystal structures of Th(BASPDA)2 were also systematically studied. It was expected that this work could provide insightful information for understanding the properties of Th (BASPDA)2 complex at the molecular level.

Pressure-induced modification of the electron structure of metallic thorium

The electronic structure of thorium (Th) in low- and high-temperature cubic phases under normal conditions and pressure has been studied using the LDA + U + SO method. Since a correct description of the physical properties of Th and other metals of the actinide series requires taking into account both the spin-orbit coupling and Coulomb interactions, the parameters of these interactions have been additionally calculated. It is established that applied pressure leads to broadening of the 5f electron states in metallic Th and causes a significant increase in their population.

Understanding the structure and electronic properties of Th4+-water complexes

We present a systematic quantum chemistry study of the [Th(H2O)n]4+(n = 1 to 10) complexes to gain insight into their electronic structure and properties: the effect of the ligand distribution on the valence shells of the thorium(IV) ion is studied by means of the electron localization function (ELF) topological analysis. Particular care is given to the study of the mono-aqua complex both at its equilibrium geometry, using various tools such as energy decomposition analyses (EDA), and along its dissociation pathway. Indeed, as several electronic states cross the Th4 +-H2O0ground state along the minimum energy path, we demonstrate that the diabatic representation implemented in MOLPRO is able to generate reference potential energy surfaces that will lead to the evaluation of diabatic dissociation curves. The calculated diabatic interaction energy curve will allow for a consistent parameterization of new generation force fields dedicated to heavy metals based on quantum chemistry.

Phase transition and thermodynamics of thorium from first-principles calculations

We report on the first-principles study of the phase transition and thermodynamic properties of the thorium metal (Th) within the framework of quasiharmonic approximation. The structural properties of Th under pressure are well reproduced. It is found that the fcc–bct phase transition occurs at 70 GPa. Based on our calculated phonon dispersion curve that is in good agreement with experiment, the thermal equation of state and thermodynamic properties, such as thermal pressure, heat capacity and entropy are obtained. All the properties of Th under high pressure and high temperature are predicted successfully.

Spin-orbit coupling in anf-electron tight-binding model: Electronic properties of Th, U, and Pu

We extend a tight-binding method to include the effects of spin-orbit coupling, and apply it to the study of the electronic properties of the actinide elements Th, U, and Pu. These tight-binding parameters are determined for the fcc crystal structure using the equivalent equilibrium volumes. In terms of the single particle energies and the electronic density of states, the overall quality of the tight-binding representation is excellent and of the same quality as without spin-orbit coupling. The values of the optimized tight-binding spin-orbit coupling parameters are comparable to those determined from purely atomic calculations.

Electrochemical Properties of Th(IV)‐Hexacyanoferrate Sol‐Gel Carbon Composite Electrode: Electrocatalytic Oxidation of Dopamine and Ascorbic Acid

AbstractA new sol‐gel carbon composite electrode using hexacyanoferrate (HCF)‐Th(IV) ion pair as a suitable modifier is fabricated in the present study. The Th(IV)‐HCF‐sol‐gel carbon composite electrode (THCF‐CCE) has been prepared by mixing methyl trimethoxysilan (MTMOS) sol‐gel precursor and carbon powder with ion pair and then to fix in a plastic tube. Cyclic voltammetry and chronoamperometry were employed to study the electrochemical and electrocatalytic properties of proposed electrode. The apparent charge transfer rate constant, ks, and transfer coefficient, α, for electron transfer between ion‐pair and sol‐gel CPE were calculated as 3.10 ± 0.10 s−1 and 0.52, respectively. The THCF‐CCE showed a significant electrocatalytic activity towards oxidation of ascorbic acid (AA) and dopamine (DA) in 0.1 M acidic phosphate buffer solutions (pH 3) containing KCl as a supporting electrolyte. The mean value of the diffusion coefficients for ascorbic acid and dopamine were found 4.12 × 10−5 and 4.43 × 10−5 (cm2s−1), respectively. High stability, good reproducibility, rapid response, easy surface regeneration and fabrication are the important characteristics of the proposed sensor. The resulting peaks from the electrocatalytic oxidation of AA and DA were well resolved with good sensitivity. A linear response was observed for AA and DA in the concentration range of 1 × 10−5 to 3 × 10−3 M and 4 × 10−6 to 2.2 × 10−4 M, respectively.

Sorption properties of Th(IV) on the raw diatomite—Effects of contact time, pH, ionic strength and temperature

Diatomite has a number of unique physicochemical properties and has diversified industrial uses. Natural diatomite has been tested as a potential sorbent for the removal of Th(IV) from aqueous solutions. The results indicate that sorption of Th(IV) is strongly dependent on ionic strength at pH<3, and is independent of ionic strength at pH>3. Outer-sphere complexation or ion exchange may be the main sorption mechanism of Th(IV) to diatomite at low pH values, whereas the sorption of Th(IV) at pH>3 is mainly dominated by inner-sphere complexation or precipitation. The competition for Th(IV) between aqueous or surface adsorbed anions (e.g., herein ClO 4 −, NO 3 − and Cl −) and surface functional groups of diatomite is important for Th(IV) sorption. The thermodynamic data (Δ H 0, Δ S 0, Δ G 0) are calculated from the temperature-dependent sorption isotherms. The results suggest that sorption process of Th(IV) on diatomite is spontaneous and endothermic.

Numerical revelation of the kinetic significance of individual steps in the reaction mechanism of methyl linoleate peroxidation inhibited by α-tocopherol

A kinetic model was constructed to describe the reactions involved in the oxidation of methyl linoleate (ML) inhibited by α-tocopherol (TH). The initial model of the reaction mechanism included 53 individual steps, which were numerically analyzed by the value method based on Hamiltonian systematization of kinetic equations. Good accord was obtained with experimental data at 40 and 50 °C. The dominant steps responsible for the antioxidant and pro-oxidant properties of TH in the process of ML peroxidation were revealed. Tocopherol-mediated peroxidation (TMP) and generation of alkoxyl radicals as a result of the reduction of hydroperoxides by TH or the decomposition tocopherol alkyl peroxides are the dominant reactions responsible for the pro-oxidant activities of α-tocopherol. The extreme behavior of reaction induction period in relation to TH initial concentration is related to the increase in the ratios of [tocopheroxyl radical]/[peroxyl radical] and the TMP rate/rate of termination by combination of tocopheroxyl and peroxyl radicals.