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For the first time, studies of the temperature dependences of the thermoelectric power for various compositions of Bi2Sr2CaxZn1−xCu2O8+y (x = 1; 0.8; 0.4) in the range 77–320 K have been carried out. The obtained experimental results are analyzed within the framework of the Xin’s two-band model. The concentration of holes per copper atom and the band gap of the semiconductor type Bi–O layers are determined. It is shown that the replacement of the calcium element with zinc in these proportions does not lead to a change in the electronic band structure of Bi2Sr2CaCu2O8+y.

This work was supported by National Research Foundation of Ukraine, project 2020.02/0217. IK would also like to thank VIAA, State Education Development Agency for Latvian state fellowship. HK would like to thank Ministry of Education and Science of Ukraine, project for young researchers No. 0119U100435. In addition, SP and AAP are thankful for financial support from Latvian Council of Science via grant lzp-2018/2-0083. HK and AAP are grateful for the support from the COST Action CA17126., The paper discusses the results of temperature studies of polymer-based nanocomposites obtained by incorporating multi-walled carbon nanotubes in thin layers of poly(3,4-ethylenedioxythophene):poly(4-styrenesulfonate), specifically focusing on interesting features in the dependencies of electrical properties across the wide range of temperatures from ambient one down to 10 K. --//-- This is the preprint version of the following article: I. Karbovnyk, H. Klym, S. Piskunov, A. A. Popov, D. Chalyy, I. Zhydenko and D. Lukashevych,The impact of temperature on electrical properties of polymer-based nanocomposites, Low Temperature Physics, 46, 1231 (2020), DOI https://doi.org/10.1063/10.0002479, which has been published in final form at https://aip.scitation.org/doi/10.1063/10.0002479., National Research Foundation of Ukraine, project 2020.02/0217; VIAA; Ministry of Education and Science of Ukraine, project for young researchers No. 0119U100435; Latvian Council of Science via grant lzp-2018/2-0083; COST Action CA17126; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART².

The infrared multiphoton dissociation (IRMPD) spectrum of the protonated heterodimer of ProPheH+, in the range of 2700-3700 cm−1, has been obtained with a Fourier-transform ion cyclotron mass spectrometer combined with an IR OPO laser. The experimental spectrum shows one peak at 3565 cm−1 corresponding to the free carboxyl O-H stretching vibration, and two broad peaks centered at 2935 and 3195 cm−1. Theoretical calculations were performed on the level of M062X/6-311++G(d,p). Results show that the most stable isomer is characterized by a charge-solvated structure in which the proton is bound to the unit of proline. Its predicted spectrum is in good agreement with the experimental one, although the coexistence of salt-bridged structures cannot be entirely excluded.

High-resolution absorption spectra of atomic krypton in the range of 11870-12700 cm $^{-1}$ were recorded by employing concentration modulation absorption spectroscopy technique with a tunable single-mode cw Ti:Sapphire laser. The krypton atoms were excited to the absorbing energy states by discharge-burning in a mixture of helium and krypton. A total of 120 lines of neutral krypton were observed, among them 33 lines had already been classified in previous studies, 45 lines were newly classified with the known energy levels, and 42 lines cannot be classified. These unclassified lines indicate that up to now unknown energy levels of Kr must exist. Further, an analysis of the unclassified lines to get possible new energy levels with a classification program is reported.

A new method to determine the arbitrary electron energy distribution function (EEDF) from the optical emission spectroscopic measurement in atmospheric-pressure plasma is introduced. The optical emission spectroscopy (OES) continuum emission spectrum, dominated by electron-neutral bremsstrahlung radiation, is analyzed to inspect the usefulness of the conventional OES measurement range for EEDF determination. The EEDF is reconstructed from the OES continuum radiation spectrum by applying machine learning to solve the bremsstrahlung emissivity equation inversely. Through iterative statistical analysis, the presented genetic algorithm can locate the EEDF reliably. Verification of the algorithm shows that theoretical Maxwellian and Druyvesteynian EEDFs can be partially reconstructed from a realistic OES measurement range. Furthermore, preliminary experimental EEDF results of an argon dielectric barrier discharge (DBD) OES measurement are given. The electron energy range and resolution of the determined EEDF are discussed. The results in this paper show potential for accurate determination of the arbitrary EEDF in atmospheric-pressure plasma using simple OES equipment.

Many Lattice dynamic models were developed in the past to study the lattice dynamics of metals and their properties. In this present study force constants of Sodium metal have been calculated with the help of De Launay Angular force model. The number of force constants varies with the nature and range of atomic interactions. In the phenomenological theories the force constant of Sodium are evaluated by making use of the experimental data on elastic constants at selected wave vectors. The basic equation of De Launay Angular force model (DAF) relates three elastic constants, force constants as well as two zone boundary frequencies. In the present study, ion-ion interactions of Sodium are considered by neglecting its electron-ion interaction from the proposed relation of DAF model because sodium is the best example of free electron. The force constants of Sodium are calculated here by restricting the range of interaction up to third nearest neighbor. The third angular force constant is considered as neglected because of weaker interaction due to conduction electrons of Sodium. The purpose of this paper is to calculate force constants of Sodium by De Launay Angular Force Model which can be used further in calculation of phonon frequencies of Sodium.

Graphene has emerged as a very promising and novel material with exceptional properties such as unique two-dimensional structure, extraordinary electronic, high carrier mobility, thermal conductivity, superior mechanical strength, and ultra-high surface area, and has potential applications in a wide range of technologies. Due to the scarcity of energy resources and the problem of environmental pollution, it is essential to adopt appropriate ways of developing new energy storage materials. Therefore, graphene has been considered as an interesting material for superior-performance electrochemical energy storage such as lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) as it can enhance the capacity, efficiency, gravimetric energy densities, and life cycles of rechargeable batteries. In this chapter, aims to introduce the definition of graphene as a novel support for nanoscale materials that react with lithium (Li)/sodium (Na) and applications in LIBs/SIBs with high capacities.

This paper reveals the structural information of lithium hydride (LiH) at high pressure. The model potential incorporate coulomb interaction potential, short range interaction and van der Waal's attraction energy within the Hafemeister and Flygare approach and the potential term as effective interionic potential model. Values obtained via this technique for LiH, revealed successful phase transition from B1 or NaCl to B2 or CsCl, The estimated transition pressure is 200 GPa, which is quite consistent with the previously available data from different theoretically techniques.

We present results of studies of formation mechanism of luminescence centers of the blue range in lithium fluoride crystals. We found that the centers under study are intrinsic defects of crystal lattice formed as a result of a radiation-thermal process in the temperature range much higher than room temperature. Experimental confirmation of simultaneous formation of these centers and F3+ centers, the increase in their concentration during thermal destruction of F3+ centers, and absence of the phonon structure characteristic of R2 centers give basis to attribute the considered centers to a stable configuration of intrinsic radiation defects constituting isomer of F3 center.

The optical spectra of BaBrI crystals activated by divalent samarium were studied. The samples exhibit bright luminescence in the red region of spectra due to 4f6–4f6 and 4f55d1–4f6 transitions of Sm2+ ions. Luminescence exhibits strong temperature dependence in the range 7–300 K. At low temperatures, luminescence associated with parity-forbidden 4f6–46f transitions from 5D0 and 5D1 states is observed. Coloring of the crystals after irradiation by ultraviolet light and long afterglow luminescence of BaBrI:Sm2+ were detected.

We present plane wave DFT calculations using van der Waals (vdW) functionals on the effects of surface coverage of Pt(111) by adsorbed benzene molecules. In particular, we study the variation of adsorption energy, preferred adsorption site and electronic structure of adsorbed benzene molecule over a range of surface coverage, including experimental saturation coverage value. We find that preferred site for adsorption changes and adsorption energy generally reduces as the surface coverage of benzene increases. Benzene molecules would preferably chemisorb until saturation coverage is attained and further form physisorbed layers on Pt(111) surface, similar to the results reported on Ni(111) and Ru(001). Benzene attains a tilted configuration with respect to the Pt(111) surface at higher coverage, in agreement with earlier experimental and theoretical data.

The process of hemolysis of erythrocyte suspension induced by hydrochloric acid (HCl) is investigated by measuring the UV-Vis absorption spectrum in the range 250 nm - 750 nm at interval 1 nm. The spectrum is measured each 15 s which permitted to follow the changes in absorbance at different wavelengths during hemolysis. The kinetics of the hemolysis is monitored by the changes in the absorbance at 700 nm, and by the changes in the wavelength of the main absorbance peak in the spectrum due to the hemoglobin. Because of the finite number and discrete values of the wavelengths used in the measurement the real value of the peak wavelengths in the spectra must be found by additional processing of the experimental data. The procedure uses the first derivative of the spectrum (dA/dt) and a geometrical approach to calculate the value of the wavelength at which the first derivative dA/dt is equal to 0. The procedure smoothed the kinetic curve of the peak wavelength to a great extent. This permit to compare it to the curve of the absorbance at 700 nm and to make assumptions of the process that occurs during the acid hemolysis. The procedure could be applied to any process where there is a shift in the peaks’ wavelength.

The report reviews the studies of the phenomenon of magnetoacoustic emission (MAE) on samples of magnetite ores from various deposits. Cube-shaped samples with a size of 24x24x24 mm are magnetized in an alternating magnetic field with an amplitude of -150 to +150 kA/m and a frequency of 0.1 Hz. The following parameters are used as MAE parameters: the values of the magnetizing field at which the maxima of the magnetoacoustic emission values are observed; the amplitude of these maxima; the range of the magnetizing field in which magnetoacoustic emission is observed; the value of the magnetic field corresponding to half the range of the magnetic field of magnetoacoustic emission manifestation (median value). It is shown that the amplitude of MAE is ambiguously dependent on the magnetite content in the sample and that it is related to the presence of internal stresses. The shape of the MAE signals and the range of the magnetizing field depend on the degree of uniformity of magnetite and on the presence of other magnetic minerals. The presence of several generations of magnetite affects the shape of the MAE signal. In this paper, an attempt is made to relate the studied parameters of magnetoacoustic emission to the petrophysical characteristics of the studied ores, as well as with the behavior of the domain structure.

Near-infrared spectroscopy has recently emerged as a powerful apparatus for rapid measurement and mostly does not require a wet chemical analysis. Non-destructive and non-invasive measurements by near-infrared spectroscopy can be realized when operated in all types of trans-reflectance modes. This paper discusses the accuracy of measuring glucose concentrations in aqueous solutions using near-infrared spectroscopy operated in a trans-reflectance mode. In this experiment, glucose with various concentrations was dissolved in water. Forty-seven samples of glucose in aqueous solutions with concentrations between 0 and 800 mg/dL were carefully prepared and divided into two sets, i.e., for calibration and validation. A partial least squares regression analysis on near-infrared spectra was applied. The results revealed that the glucose content in aqueous solutions could be predicted accurately, indicating that the near-infrared prediction is sufficient to determine the glucose content in the physiological range.

In-depth measurements are reported for the imaginary parts of AC conductivity to understand the conduction mechanism of amorphous Se80-xTe20Pbx (x = 0, 1 and 2) chalcogenide glassy alloys in the frequency range 10 Hz to 500 kHz and over the temperature range 300 K to 320 K. The investigated chalcogenide alloys were prepared using melt-quenching technique and sub-micron structural features are also reported. The absence of any sharp characteristics peaks in x-ray diffraction spectra signify the amorphous nature of each examined glassy compositions, which is further validated by field emission scanning electron microscopy (FESEM). The deduced results are analyzed in the light of various theoretical models. A detail analysis reveals that the correlated barrier hopping (CBH) model is most appropriate to describe the conduction mechanism in these investigated amorphous alloys.

Lanthanum-perylene complex compounds has been studied for their fluorescence properties s as metal detectors. Selectivity to Cu2+ and Pb2+ metal ions at the neutral pH (pH 7) and higher pH (pH 12) was shown, in which the addition of Cu2+ and Pb2+ metal ions resulted in the quenching of fluorescence intensity. The result indicated the lanthanum-perylene complex is an on-off fluorosensors. On the opposite, the addition of metal ions such as Ni2+, Co2+, and Cd2+ did not show any significant change in the neutral or higher pH. Furthermore, lanthanum-perylene complex was able to detect Cu2+ metal ions in the range of concentration from 1×10−4 M to 1×10−8 M, while Pb2+ metal ions in the range of concentration from 1×10−4 M to 1×10−6 M.

A comparative study of perovskite material has been done by exposing samples to cesium 137 gamma rays. Monte Carlo simulation is accomplished for the Cs137 ion sputtering of CH3NH3PbI3 (lead perovskite) and its lead replaced equivalent, CH3NH3SnI3 (tin perovskite) as a latest perception of civilizing the lead free perovskite material. Currently, the lead free perovskites give inferior PCE than lead perovskite. In this paper, it is reported that the sputtering results and projected range result behavior is quite similar for lead and tin perovskites [2]. In fact, an another reason to improve the properties of tin perovskite for solar cell application despite of its poor PCE.

In the present study, cross-sections were evaluated for the production of the active indium isotopes: 111In (t1/2=2.83 days) and 114In (t1/2=71.9 S) via a bombardment of an enriched Cadmium target with proton beams upto70MeV. Utilizing high cyclotron yield and the optimum cyclotron energy range was chosen for the production of Indium isotopes. The best reactions for producing 111In is 112Cd (p,2n)111In, and for 114In is 116Cd (p,3n)114In. The programs which evaluating cross-sections and the yield were built using Matlab in the present work. The cross-sections of (p,xn) reactions for the production of indium isotopes were assessed depending upon the empirical data taken from the EXFOR library, which is belonging to the International Atomic Energy Agency (IAEA).

Nanoferrofluids of Mg0.5Co0.5Fe2O4 were prepared by chemical co-precipitation method by varying the pH value. The structural and surface morphological investigations were done by XRD and SEM techniques respectively. The particle size calculated from XRD, (3 1 1) plane revealed that the particle size increases with decrease in pH value and are in the range of 18 - 52 nm. Ultrasonic waves of different frequencies passing through nanoferrofluids with different velocity at different temperatures helps in studying the chemical and physical properties of nanoferrofluid. In the present study ultrasonic waves are passed through the aqueous carrier fluid and Magnesium doped cobalt nanoferrofluids by varying the temperature in the range of 30-70 oC. From the experimental data, various acoustical parameters such as Rao's constant, Wada constant and adiabatic compressibility have been evaluated. The increased ultrasonic velocity of nanoferrofluid than that of the carrier liquid in the absence of magnetic field indicates a strong interaction between the solute and solvent.

Fine metallic fragments in the millimeter and submillimeter size ranges may result from high-velocity impact with an obstacle or from explosive dispersal of particles. The size, velocity, and spatial distribution of the fine fast-flying particles are difficult to determine with available diagnostic systems. A novel particle impact detector based on a high-sensitivity tribolumi- nescent (TL) screen that is described in this paper can, in principle, fill this niche. The light-generating impact screen utilizes a TL manganese-doped zinc sulfide (ZnS:Mn) powder. The polycrystalline bulk TL material is synthesized in-house using the self-propagating high-temperature synthesis (SHS) reaction between sulfur and zinc. The multilayered sensor screen is comprised of aluminum foil, a layer of coarse polycrystalline particles, and transparent plastic backing. The sensor is optically coupled to a photomultiplier via a fiber optic taper. The operation of the system is demonstrated by impacting the screen with particles in the 0.1–0.6 mm size range accelerated by a helium-driven light-gas gun to speeds in the 0.3–0.8 kms−1 range. The sensor is shown to resolve particle impacts even in dense flows, allowing correlation of the signal amplitude with particle kinetic energy, and can resolve the bow shock as a precursor signature prior to particle impact.

Using transfer matrix method, we theoretically study the reflectance and transmittance behavior of one-dimensional photonic crystal made up of alternate layers of high Tc-superconductor (Bi2Sr2Ca2Cu2O8) and dielectric material at different temperatures and at different angle of incidence. From the study, we observe that the range of 100% reflectivity decreases as the temperature is increases and width of the photonic band gap increases with increases of angle of incidence and number of periodic layers.

Oxygen in interstitial (Oi) always plays an important role for the formation of oxygen related donors in CZ-silicon. The behavior of Oi in cz-silicon in the temperature range 450 °C to 510 °C has been investigated using FTIR for the wave number range 1200 cm−1 to 2500 cm−1. Many IR peaks formed at 450°C show the formation of donors and at 465°C many of them are disappeared. The strengthening of the IR band peaking at around 1587 cm−1 occurs at 450°C, while it disappears at 480°C. However, the line at 2357 cm−1 appears with strong intensity at 480°C. The isotopic shifts for different configurations for Oi in Silicon have been also reported.

Due to their excellent optical properties, luminescent carbon dots can find application in various fields, including biomedicine, sensing, and optoelectronics, and in particular for the development of advanced white light- emitting diodes (LEDs). Herein, we developed a microwave-assisted colloidal synthesis of five types of carbon dots starting from o-phenylenediamine as a precursor. The emission of fabricated carbon dots can be tuned over a wide spectral range (430-590 nm) by using nitrogen-containing solvents or additional precursors of different nature, including organic acids and polymers.

Optically transparent SiO2 glass was implanted in a pulsed mode with 30 keV Bi-ions with different doses: 1016, 5·1016, 1017, 3·1017 pcs/cm2. The depth of penetration of ions into the studied SiO2 samples was estimated using the SRIM software package and is in the depth range of 10-60 nm. Optical absorption spectra were recorded on a vacuum spectrophotometer McPherson VuVAS 1000 Pl. It has a non-elementary form, which indicates the presence of active centers and structural defects associated with intrinsic defects of silicon dioxide glass, as well as with bismuth ions.

The proposed sample of Zinc substituted Yttrium ferrite has been synthesized through Sol-Gel technique. The Phase formation and crystalline symmetry has been confirmed using the X-ray diffraction study. Detailed dielectric behavior has been analyzed in the broad frequency (100Hz to 1MHz) range at various temperatures in between RT to 623K which reflect the strong dependency of dielectric parameters on frequency and temperature. The dielectric anomaly appeared near the temperature 500K is showing the ferro-electric to para-electric transition. The temperature dependent current-voltage analysis has been done in between RT to 673K which shows the non linear and linear behavior at low and high temperature respectively.

The glass forming ability of titanium tellurite and bismuth tellurite glasses have been studied and compared. Titanium tellurite glasses require high melt quenching rates and hence, were synthesized by splat-quenching technique while the bismuth tellurite glasses require further high quenching rates owing to which they were synthesized using ice quenching. It is observed that xTiO2-(100-x)TeO2 glasses have poor glass forming ability (GFA), but for bismuth tellurite glasses in addition to their poor ability to form glasses, they have a very limited glass formation range (up to 5-mol %). At high Bi2O3 content (10-mol %) long-range order co-exists with the disturbed short-range order due its anti-glass phase formation. Bi2O3 and TiO2 incorporated jointly into the tellurite network also shows the properties of their anti-glass nature since there exist sharp peak superimposed upon a broad hump in XRD while the vibrational studies show broad bands. However, incorporating B2O3 into the system suppresses the anti-glass phases present and forms purely a glassy sample. Raman studies found a decrease in the Te—O coordination with increase in Bi2O3 and B2O3 concentration while no effect on the Te-O speciation is observed for TiO2 modified tellurite glasses.

Nowadays, radiation has been utilized and importance in our daily life. Importantly, the radiation to achieve most effective goal and prevent radiation hazards for safe and accuracy. The principle of radiation protection are called "As Low As Reasonably Achievable" make sure staff follow these 3 major safety principles consisting of distance, time, and shielding. The radiation shielding material are common used as lead in manufacturing process lead are high toxicity. Therefore, the researcher is interested in using other elements to replace lead. This study used by glass structure formula (60-x) P2O5: 10Al2O3: 20Na2O: 10Gd2O3: xHo2O3 where x = 0.00, 0.05, 0.10, 0.50, 1.00 and 3.00 mol%. The result shows that the linear attenuation coefficient (µm) was increased when Ho2O3 concentration were increased. The mass attenuation coefficient (µ) was increased when Ho2O3 concentration were increased. The half value layer (HVL) was decreased when Ho2O3 concentration were increased. The results in this study in glass formula 57P2O5: 10Al2O3: 20Na2O: 10Gd2O3: 3Ho2O3 has high quality in the X-ray shielding range of 50-120 kVp compared to the concentration of 0.00, .0.0, .0.., 0.50 and 1.00 mol% respectively. The HVL of glass samples doped with Holmium compared with commercial windows, red brick, concrete, X-ray windows, and the results show that 0.50, 1.00 and 3.00 % mole the HVL less than X-ray glass. This study shows the properties of Ho2O3 in X-ray shielding and highly practical potentials in the environmental friendly radiation shielding materials without an additional of lead.

MgO is used as an optical element in multilayer mirror for synchrotron beamlines applications. However, it is highly hygroscopic in nature leading to deterioration of its optical properties. In this study we have shown how the optical properties of MgO thin film modifies on its exposure to ambient condition in the energy range of 45-70 eV covering the Mg L-edge region. We have carried out energy dependent soft X-ray reflectivity measurements on freshly prepared and aged MgO thin film for determination of optical constants. It is observed that the optical constants values of the aged sample deviate from the freshly prepared sample owing to water adsorption and increasing surface roughness as confirmed from atomic force microscopy (AFM) images.

The electronic structure and optical properties of GdNi2Mnx compounds (x = 0, 0.4, 0.6) were investigated. Spin-polarized electronic structure calculations were performed in the approximation of local electron spin density corrected for strong electron correlations using the LSDA+U method. The changes in the magnetic moments and exchange interactions in GdNi2Mnx (x = 0, 0.4, 0.6) governing the increase in the Curie temperature with manganese concentration were determined. The optical constants of the compounds were measured by the ellipsometric method in the wide spectral range of 0.22–15 μm. The peculiarities of the evolution of the frequency dependences of optical conductivity with a change in the manganese content were revealed. Based on the calculated densities of electron states, the behavior of these dispersion curves in the region of interband absorption of light was discussed. The concentration dependences of several electronic characteristics were determined.

Cadmium zinc telluride (CZT) is an ideal material for room temperature nuclear radiation detection, but CZT crystals of high quality and low defects concentration are difficult to obtain. Therefore, in order to improve the performance of the CZT detector, the working conditions of the CZT detector could be appropriately changed to make the internal electric field of the CZT detector close to uniform distribution so as to improve the electron transport performance. In this paper, alpha induced transient charge analysis has been used to study the internal electric field of the CZT detector, and deep level defects in CZT were linked with internal electric field distribution. Based on the process, a variety of deep level defects on electron trapping and detrapping by changing the temperature, the output waveform change of charge sensitive preamplifier (the pulse height spectra for alpha radiation at different temperatures) was observed, and then the effects of deep level defects on electron mobility ( μe), electron transport time ( TR), the internal electric field, and the electron collection efficiency of the CZT detector were analyzed. The experimental results indicated that the influence of deep level defects was a main factor to the internal electric field in the range of −140 to 40 °C. As the temperature rises, the influence of these defects weakens, μe and electron collection efficiency both increase, and internal electric field distribution tends to be uniform. Moreover, with the further increasing temperature (−40 to 20 °C), μe decreased and internal electric field distribution became fluctuating, but electron collection efficiency was basically unchanged, which suggested that the influence of lattice vibration in the range of −40 to 20 °C turned to be the main factor. The above conclusions demonstrated that although the CZT detector has excellent room temperature detection ability, room temperature was not its optimal working temperature due to the influence of high concentration deep level defects. At −20 °C, the CZT detector presented the highest electron collection efficiency and maximum which limited the influence of deep level defects on electron transport, performing the optimal properties.

The crystal structure of tungsten monocarbide (WC) is researched from 0 to 650 GPa through first principles calculations. The results verify that the experimental structure (hP2-WC) with the space group P 6¯m2 is the most stable phase in a wide range of pressure. Above 231 GPa, a new stable structure (space group P63/mmc, hP4-WC) is found to be the most stable phase, and it will transform to a CsCl-type phase (cF8-WC) around 582 GPa. Phonon calculations reveal that the hP4-WC phase is dynamically stable and may be a metastable structure at ambient conditions. The cF8-WC phase possesses dynamical stability above 20 GPa. The hP4-WC phase is a low compressible material with a large bulk modulus of 377 GPa at zero pressure. The hardness values of hP2-WC and hP4-WC at zero pressure are 32 and 21 GPa, respectively, while the cF8-WC phase possesses a hardness of 21 GPa at 20 GPa, implying that these phases are potential hard materials. The temperature–pressure phase boundary of WC is obtained by means of the quasi-harmonic approximation method. As the temperature increases, the transition pressure from hP2-WC to hP4-WC remained nearly unchanged. The transition pressure between hP4-WC and cF8-WC decreases with the increasing temperature.

We report the laser intensity dependence of multiply charged atomic ions (MCAIs) Arn+ with 2 ≤ n ≤ 8 from argon clusters in focused nanosecond laser fields at 532 nm. The laser field, in the range of 1011–1012 W/cm2, is insufficient for optical field ionization but is adequate for multiphoton ionization. The MCAI sections of the mass spectra for clusters containing 3700 and 26 000 atoms are dominated by Arn+ with 7 ≤ n ≤ 9, extending to Ar14+. While the distributions of the MCAIs remain largely constant throughout the intensity range of the laser, the abundance of Ar+ relative to the abundances of the MCAIs increases dramatically with increasing laser intensity. Consequently, exponential fittings of the yields result in a larger exponent for Ar+ than for MCAIs, and the exponents of MCAIs with 2 ≤ n ≤ 8 are similar, with only slight variations for different charge states. The width of the arrival time and, hence, the corresponding kinetic energy of Ar+ also increases with increasing laser intensities, while the width of the arrival time of MCAIs remains constant throughout the range of measurements. These results call for more detailed theoretical investigations in this regime of laser–matter interactions.

Granular molecular crystals show a large variation in the orientation, length, shape, and cohesive interactions of interfaces when embedded in a polymer matrix. But the determination of the associated excess of free energy is not straightforward, especially due to the entropic contribution which is not negligible for molecular compounds. The surface free energy (SFE) is also important to predict crystal shapes and growth or to prove crucial insights into the mesoscale interfaces in the granular composites often with interfacial defects, voids, and pores. In this paper, we use Molecular Dynamics (MD) and assess and adapt two non-equilibrium methods, namely, non-equilibrium thermodynamic integration (NETI) and modified steered MD (SMD), to determine the SFE of various facets of a high-energy molecular crystal of interest: β-HMX. Starting with defect-free surfaces, both methods agree well with experiment concerning the most stable facets, whose energy is further lowered by a large entropic contribution. For some facets, surface creation (debonding process) and annihilation (bonding process) show fundamentally different paths, henceforth irreversible. Then, we discuss some sources of discrepancy between theoretical and experimental SFE, considering non-reversible dissipative events, surface roughness, and differences between various experimental techniques. These non-equilibrium methods can be applied to a wide range of molecular crystals and to study interface stability in polycrystals or with binding polymers, including the effects of various defects.

The dimer under study is a dielectric structure formed of two identical sub-units. Dimer interactions with electromagnetic waves are widely studied in connection with electromagnetic properties of complex systems. The dimer in the form of two closely spaced grapes is also a subject of high public interest because its gap region sparks curiously in a household microwave oven. A recent paper presented the first scientific interpretation of this long-standing puzzle. It attributed the sparking phenomenon to an electromagnetic hotspot in the gap created by electromagnetic resonances in the dimer. This study has opened up a fertile ground for further research as well as motivating the current study on an independent mechanism. Our simulation and experimental results consistently point to an electrical origin for the sparks. The triggering mechanism is a two to three orders-of-magnitude buildup of localized electric field in the narrow gap, which results from the mutual enhancement of polarization charges on opposite sides of the gap. Consequently, sparks are observed at the frequency of 27 MHz, at which no electromagnetic resonance in the dimer is possible. Results also indicate a broad frequency range of the electrical mechanism, which persists even when the dimer is in strong electromagnetic resonance with the first few higher-order modes. These quantitative characterizations of basic dimer properties, in particular the broad frequency range of the polarization-charge enhancement effect, may be helpful for the understanding of collective behavior of multi-particle systems under electromagnetic radiations.

A numerical tool for analysing spatially anisotropic electron populations in electron cyclotron resonance (ECR) plasmas has been developed, using a trial-and-error electron energy distribution function (EEDF) fitting method. The method has been tested on space-resolved warm electrons in the energy range $2-20\,\mathrm{keV}$, obtained from self-consistent simulations modelling only electron dynamics in ECR devices, but lacked real-world validation. For experimentally benchmarking the method, we attempted to numerically reproduce the experimental X-ray emission spectrum measured from an argon plasma. Results of this analysis have provided crucial information about density and temperature of warm electrons, and competing distributions of warm and hot electron components. This information can be fed back to simulation models to generate more realistic data. Subsequent application of the numerical tool as described to the improved simulation data can result in continuous EEDFs that reflect the nature of charge distributions in anisotropic ECR plasmas. These functions can be also applied to electron dependent reactions, in order to reproduce experimental results, like those concerning space-dependent K$\alpha$ emissions.

Antiferromagnets are one of the few candidate materials that can work at THz frequency and are, therefore, a potential material for THz technology recently attracting interest from high-speed communication and sensing applications. In this work, we investigate an antiferromagnetic resonant frequency ( ω r) tunability for cation doped α-Fe2O3. It is found that, with various cation dopants (Al, Ru, Rh, and In), the resonant frequency can be tuned in a range between a millimeter-wave band and a THz band. We also complementally discuss the mechanism of the Morin temperature ( T M) shift upon cation doping by the temperature and dopant dependence of ω r. A good frequency tunability shown in this work suggests that cation doped α-Fe2O3 is a useful material for millimeter-wave and THz applications.

Chlorine-based gases are used for the reactive ion etching (RIE) of β − Ga 2 O 3. However, the effects of Cl-plasma on the electronic properties of β − Ga 2 O 3 are not known. In order to shed light on this topic, we carried out an experimental and theoretical study on β − Ga 2 O 3 epilayers treated with Cl 2 / Ar or BCl 3 / Ar plasma. We found four traps in the 0.2–0.8 eV energy range below the conduction band edge ( E C). Two of these, located at E C-0.24 eV and E C-0.28 eV, arise only when the epilayers are treated with BCl 3 / Ar. While the involvement of Cl in their microscopic structure is not discarded, the possibility that these two levels might have an intrinsic nature seems more plausible. Our findings might explain the reported effects on the Schottky barrier diodes of β − Ga 2 O 3 when RIE is employed during processing.

Differential and integral cross sections for elastic and electronically inelastic scattering of electrons by the thiophene molecule were determined by means of the Schwinger multichannel method within the static-exchange plus polarization approximation in the energy range from 3.41 to 50 eV. We investigated the influence of multichannel coupling effects by calculating the cross sections according to different schemes of channel coupling that range from 1 to 61 open channels along with polarization effects, depending on the energy considered. The comparison of these results shows that the inclusion of more channels in the scattering calculations leads to a significant decrease in the magnitude of the cross sections. Present results corresponding to our best level of channel coupling at a given energy, both for elastic and electronically inelastic electron scattering by thiophene, display an overall good agreement with the data available in the literature.

Wire explosion is a technically straightforward green method for nanoparticle production; however, the determination of polydisperse and multimodal particle size distribution and thereby the assessment of the efficiency of the process pose serious challenges. Fitting extinction spectra derived from the Mie theory to the measured extinction spectra of colloidal solutions produced by the explosion of copper wires of 70 μm diameter and 20 mm length by discharging a capacitor of 435 nF charged to voltages ranging from 4 to 12 kV in an aqueous environment allows for determining the size distribution of the particles in the 10–300 nm diameter range and provides information on their oxidation state as well. In underwater wire explosion of copper, the vast majority of the nanoparticles transforms into copper oxides already during the process. The size distribution remains bimodal throughout the whole charging voltage range investigated. The nanoparticles follow a lognormal size distribution with a mode at 30 nm, while the fine particle population extending from 100 to 300 nm in diameter is dominated by rather normally distributed copper droplets with modes at 160–170 nm. The energy injected into the wire controls the individual concentration of both the fine and nanoparticles with the modes and ranges remaining hardly affected. The number concentration of the nanoparticles increases monotonically with the energy, spanning more than one order of magnitude. The throughput assessed by the total mass of the nanoparticles divided by the total mass of all species identified in the sol within the 0–300 nm diameter range increases monotonically from 1% at 4 kV up to 41% at 12 kV, revealing that wire explosion can be optimized for efficient nanoparticle production.

Propionitrile (CH3CH2CN, PN) is a molecule relevant for interstellar chemistry. There is credible evidence that anions, molecules, and radicals that may originate from PN could also be involved in the formation of more complex organic compounds. In the present investigation, dissociative electron attachment to CH3CH2CN has been studied in a crossed electron–molecular beam experiment in the electron energy range of about 0–15 eV. In the experiment, seven anionic species were detected: C3H4N−, C3H3N−, C3H2N−, C2H2N−, C2HN−, C2N−, and CN−. The anion formation is most efficient for CN− and anions originating from the dehydrogenation of the parent molecule. A discussion of possible reaction channels for all measured negative ions is provided. The experimental results are compared with calculations of thermochemical thresholds of the detected anions.

In this tutorial article, we review the technological, physics, and economic basis for a magnetic fusion device utilizing a flowing liquid lithium divertor (molten metal velocity in the range of cm/s) and operating in a low-recycling plasma regime. When extrapolated to magnetic fusion reactor scale, the observed effects of a liquid lithium boundary on recycling reduction, confinement increase, and anomalous heat transport mitigation may offer a fundamentally distinct and promising alternative route to fusion energy production. In addition, this lithium-driven low recycling regime could accelerate fusion's commercial viability since such a device would be smaller, dramatically decreasing plant and electricity costs if all technological complexities are solved. First, the theoretical basis of the energy confinement and fusion performance as well as the related possibilities of low recycling regimes driven by flowing lithium plasma-facing components are reviewed. Then the paper emphasizes the technological obstacles that need to be overcome for developing the necessary systems for such a flowing liquid lithium solution at reactor scale and details how many of these have been overcome at laboratory and/or proof-of-concept scale. Finally, the current and planned scientific and engineering endeavors being performed at the University of Illinois at Urbana-Champaign regarding this alternative reactor option are discussed.

The irradiation-induced sputtering and the structural damage at tungsten surface are investigated by using molecular dynamics simulations at the level of quantum mechanics. Our simulations indicate that the sputtered atoms appear when the energy of incident primary knock-on atom (PKA) is more than 200 eV and the incident angle of the PKA is larger than 65°. Meanwhile, the irradiation-induced vacancies are less when the incident angle of PKA is in the range of 45°–65°. So, the optimum incident angles of PKA are suggested to reduce the irradiation-induced damage of the W surface. Furthermore, we find that the interstitials contained in the systems accelerate the sputtering whereas the intrinsic vacancies suppress the sputtering when the PKA is near the defects.

We present the energy dependence of the cross section for the inelastic interaction of protons with the tungsten in the energy range from an order GeV to a hundred GeV using the data of the PAMELA space experiment. It was intended for the precision measurements of the cosmic ray fluxes of different nature and include a set of detectors for the reliable determination of the particle characteristics. We present the comparison of the obtained results with the measurements at accelerators and with existing theoretical models. The results of the work can be demanded for the development of numerical models describing particle’s interactions.We present the energy dependence of the cross section for the inelastic interaction of protons with the tungsten in the energy range from an order GeV to a hundred GeV using the data of the PAMELA space experiment. It was intended for the precision measurements of the cosmic ray fluxes of different nature and include a set of detectors for the reliable determination of the particle characteristics. We present the comparison of the obtained results with the measurements at accelerators and with existing theoretical models. The results of the work can be demanded for the development of numerical models describing particle’s interactions.

Two different experimental techniques, namely positron lifetime spectroscopy (PALS) and electron energy loss spectroscopy (EELS), were used in a complementary fashion to provide actual helium concentration in a range of cavities induced by irradiation in spallation conditions. Results of the experiments on ferritic/martensitic steels with 450 – 1800appm of helium show helium-to-vacancy ratios 0.2 – 1, inversely proportional to the sizes of the vacancy clusters. While in low-dpa sample, the helium is predominantly confined in small vacancy clusters (He-to-vacancy ratio ∼ 1), high-dpa sample contains a high number density of helium-filled bubbles. The obtained results are in a good agreement with the molecular dynamics simulations published in the literature.Two different experimental techniques, namely positron lifetime spectroscopy (PALS) and electron energy loss spectroscopy (EELS), were used in a complementary fashion to provide actual helium concentration in a range of cavities induced by irradiation in spallation conditions. Results of the experiments on ferritic/martensitic steels with 450 – 1800appm of helium show helium-to-vacancy ratios 0.2 – 1, inversely proportional to the sizes of the vacancy clusters. While in low-dpa sample, the helium is predominantly confined in small vacancy clusters (He-to-vacancy ratio ∼ 1), high-dpa sample contains a high number density of helium-filled bubbles. The obtained results are in a good agreement with the molecular dynamics simulations published in the literature.

Organic dye solutions in suitable liquid solvents are now widely used as a laser gain medium for generating coherent tunable radiation and also in photonic applications. Kirkwood Buff Integrals (KBI’s) play a significant role in characterizing interactions in liquid systems. In this study, we utilise the experimentally obtained sound velocity and density measurements at different concentrations of a dye, 7 Amino-4-(trifluromethyl)coumarin (C10H6F3NO2) in the mixture of ethanol and benzaldehyde over the entire composition range to evaluate these integrals for investigating solute-solvent interactions.

AlSb thin-film solar cell consisting of p-type AlSb was prepared on n-type Si substrate by using thermal evaporation. The effect of the preparation and partial replacement of Aluminum with Indium of the Al1-xInxSb were studied to obtain the best properties. Thin films have been deposited on glass substrate at R.T with ratios (X=0.0, 0.1 and 0.3) under the vacuum of 10−6 Torr with (150) nm thickness. Structural, optical and electrical properties of the films were investigated, I-V characteristics studies as ratios of Indium increased, measurements indicate formation of good quality thin films of AlSb having band gap within the range reported in the literature.

At present semi-crystalline ferroelectric polymers and several organic molecular ferroelectrics are suitable for a large variety of flexible devices as an electrical energy storage application. Considerable progress has been made over the past several years in the enhancement of energy density of ferroelectric polymers, carbon nanotube (CNT) and also organic ferroelectrics. Realizing the application potential, this review article summarizes a range of several applications of PVDF composites, CNT and organic ferroelectrics in the field of memory elements. This article also highlights on dielectric capacitor and other energy storage devices with advantages and disadvantages.

Additive manufacturing processes allow the production of individualized and complex parts without the use of molds or tools. Especially powder and beam-based AM processes like selective laser sintering (SLS) of polymers are promising, although the choice of commercial SLS powders is very limited. To further extend the applications of SLS, new and cheap materials with good processability must be supplied. Within this contribution two innovative methods for production of spherical polymer micro particles for SLS are discussed: The first approach is a process chain applicable to a wide range of polymers consisting of wet grinding in a stirred media mill followed by rounding of the obtained irregular- shaped particles in a heated downer reactor and subsequent dry coating of the spherical particles for improvement of powder flowability. It will be outlined for glass-filled PBT systems. The second approach is melt emulsification with subsequent dry coating. In this process a polymer melt is emulsified by elongational and shear stresses in a rotor stator device. The method is exemplified for polypropylene (PP). Both approaches allow for production of spherical polymer micro particles. The effect of flowability, shape and bulk density on the powders’ processabilities in SLS is assessed.

Lithium boro bismuth tellurite glasses doped with Er3+ ions were successfully prepared by conventional melt quenching method and investigated their temperature dependent AC conductivity through impedance analyzer. The frequency dependent AC conductivity has been analyzed using Almond-West type of power law. The conductivity increases with increase of both frequency and temperature. The obtained conductivity values lie in the range of 4.092x10−5 to 3.024x10−5 S/cm. The AC conductivity mechanism can be reasonably inference in terms of correlated barrier hopping (CBH) model.Lithium boro bismuth tellurite glasses doped with Er3+ ions were successfully prepared by conventional melt quenching method and investigated their temperature dependent AC conductivity through impedance analyzer. The frequency dependent AC conductivity has been analyzed using Almond-West type of power law. The conductivity increases with increase of both frequency and temperature. The obtained conductivity values lie in the range of 4.092x10−5 to 3.024x10−5 S/cm. The AC conductivity mechanism can be reasonably inference in terms of correlated barrier hopping (CBH) model.