Search

The T(1H, γ)4He reaction has been studied for the first time in the energy range Elab = 12–34 keV in the laboratory coordinate system (E = 7.8–20.1 keV in the center-of-mass system). The study of this reaction is of interest because it is involved in the primary nucleosynthesis of 4He and is important for the theory of few-nucleon systems. The reported experiment improves the accuracy of the experimental determination of the S-factor of the T(1H, γ)4He reaction by several times. The theoretical calculations of the S-factor of the T(1H, γ)4He reaction still differ from the experimental values by a factor of about 2.

The article is devoted to study of the D(3He, p)4He reaction in the 3He+ ion energy range EHe = 16÷34 keV (E= 6.41÷13.61 keV in the center-of-mass system) with a step of 2 keV. The goal of this paper was to determine experimentally the electron screening potential U e and the enhancement factor of the D(3He, p)4He reaction using the deuterated metal targets ZrD with different crystal textures. In this work we present results of measuring the D(3He, p)4He reaction enhancement factor using the targets ZrD with Miller indices [111] and [100]. The ZrD targets was deposited on the stainless steel foil 50 μm thick. The protons of energy 14.7 MeV from the D(3He, p)4He reaction were detected by a scintillation detector based on the BC-404 scintillator 115 mm in diameter and 4 mm thick, which was placed in optical contact with the XP-2040 PMT. The measured enhancement factors of the D(3He, p)4He reaction much higher than for gas targets and energy behavior is not described by the classical exponential formula. The effect of the crystal structure of the targets is evident. The measured enhancement factors of the D(3He, p)4He reaction are higher for the ZrD target with a crystal structure characterized by the Miller index [100] than for the target with index [111], which probably indicates the contribution of channeling. A non-proportional increase of the enhancement factors for the D(3He, p)4He reaction in energy range 16÷22 keV probably indicates a low-lying resonance effect in 5Li.

The study of fusion reactions $$\hbox {D}(\hbox {d}, \hbox {p})^{3}\hbox {H}$$, $$\hbox {D}(\hbox {d}, \hbox {n})^{3}\hbox {He}$$, $$\hbox {T}(\hbox {d}, \hbox {n})^{3}\hbox {He}$$, $$^{3}\hbox {He}(\hbox {d}, \hbox {p})^{4}\hbox {He}$$, and $$\hbox {D}(^{3}\hbox {He}, \hbox {p})^{4}\hbox {He}$$ at astrophysical energies is of interest for both basic and applied physics. These studied provide information on electron screening of nuclear reactions that provide important information on the role of electrons in reactions induced by deuterons, tritons, and nuclei of helium isotopes that proceed in reactors. The $$\hbox {D}(^{3}\hbox {He}, \hbox {p})^{4}\hbox {He}$$ reaction was investigated at the pulsed plasma Hall accelerator (Tomsk) in the $$^{{3}}\hbox {He}^{{+}}$$ ion energy range $$E_{\mathrm{He}} =16\div 34$$ keV (laboratory reference frame) with a step of 2 keV. The goal of this work was to determine experimentally the enhancement factor of the $$\hbox {D}(^{{3}}\hbox {He}, \hbox {p})^{{4}}\hbox {He}$$ reaction and the electron screening potential $$U_{\mathrm {e}}$$ using a TiD targets with Miller indices [111] and [100]. A strong impact of the target crystal structure on reaction enhancement factor was discovered. We believe that solid-state effects make the largest contribution to the behavior of the enhancement factor $$\hbox {D}(^{{3}}\hbox {He, p})^{{4}}\hbox {He}$$ of the reaction as a function of energy. One of these effects is the particle channeling in crystal structures. An unexpected increase of the enhancement factors for the $$\hbox {D}(^{{3}}\hbox {He, p})^{{4}}\hbox {He}$$ reaction in the energy range $$16\div 22$$ keV probably indicates the emergence of some new mechanism that increases the yield of the reaction with lowering energy.

The D(3He, p)4He reaction is first investigated in a solid target of deuterated zirconium (ZrD) in the 3He+ ion energy range EHe = 18–30 (E = 7.2−12.0keV keV in the center-of-mass system) with a step of 2 keV. The electron screening potential Ue = (617.8 ± 154.7) eV and the D(3He, p)4He reaction enhancement factors are experimentally determined in the given energy range. The measured electron screening potential is six times higher than in gaseous targets. This can be due to the ZrD lattice effects, which have not been studied either theoretically or experimentally so far. The D(3He, p)4He reaction has been investigated at the pulsed plasma Hall accelerator (Tomsk).

The study of thermonuclear reactions such as D(d, p)3H, D(d, n)3He, T(d, n)3He, 3He(d, p)4He, and D(3He, p)4He is of great interest in the field of astrophysics, as it affects the primordial nucleosynthesis, as well as issues of stellar dynamics. These reactions are also of interest in thermonuclear power engineering, in connection with the increased interest in the possibility of practical application of thermonuclear fusion. In this work, the analysis of the results obtained in the course of studying the reaction D(3He, p)4He was carried out. The results were obtained by us in previous works on deuterated metal targets ZrD and TiD with Miller indices [111] and [100]. There is a need to more precise study of the effects accompanying thermonuclear reactions at low astrophysical energies. The purpose of this work is to study the behavior of the screening potential [Formula: see text] and the reaction enhancement factor [Formula: see text], depending on the crystal structure of targets and the interaction energy. The studies were carried out on a Hall accelerator (Tomsk, TPU) in the energy range [Formula: see text]([Formula: see text][Formula: see text]keV in lab reference frame with a step of 2[Formula: see text]keV. Experiments have shown that in reactions using metal deuterated targets a similar effect as in reactions using gas targets was observed. Specifically, an electron screening effect was observed, which leads to an increase in the reaction cross-section with decreasing energy, and in case of metal target this effect becomes stronger.

The nature of background processes accompanying astrophysical nuclear reactions induced by hydrogen, helium, and neon ions in deuterated targets with small cross sections has been studied in calculations and experiments. The experiments have been performed at a Hall pulsed plasma accelerator in the ion energy range of 26–32 keV. The yield of background neutrons and γ-quanta with energies below 4 MeV in the proton-induced D(p, γ)3He reaction is primarily due to the presence of a natural impurity of gaseous deuterium in gaseous hydrogen and the chain of D(D, 3He)n → (n, γ) or (n, n'γ) reactions. A small contribution comes from the chain of D(1H, 1H)D → D(D, 3He)n → (n, γ) or (n, n'γ) reactions. It has been shown that background neutrons and γ-quanta from the D(4He, γ)6Li reaction are entirely due to the chain of D(4He, 4He)D → D(D, 3He)n → (n, γ) or (n, n'γ) reactions. It has been shown that the yield of neutrons and γ-ray photons detected at the interaction of neon ions with deuterated targets is also entirely due to the chain of elastic- scattering reactions of neon ions on deuterons in the target and to subsequent inelastic processes of interaction of deuterons accelerated at elastic scattering with other deuterons of the target. The main contribution to the yields of background neutrons and γ-quanta comes from doubly charged neon ions. The main conclusion is that the explanation of the yield of neutrons and γ-quanta at the interaction of hydrogen, helium, and neon ions with deuterated targets does not require “exotic” theoretical models.

The astrophysical S-factor of the reaction T(4He, γ)7Li is measured for the first time at the center of mass energy E cm = 15.7 keV, lower than the energy range of the Standard Big Bang Nucleosynthesis (SBBN) model. The experiment is performed on a Hall pulsed accelerator (TPU, Tomsk). An acceleration pulse length of 10 μs allows one to suppress the background of cosmic radiation and the ambient medium by five orders of magnitude. A beam intensity of ~ 5 × 1014 4He+ ions per pulse allows one to measure an extremely low reaction yield. The yield of γ-quanta with the energies E γ 0 = 2483.7 keV and E γ 1 = 2006.1 keV is registered by NaI(Tl) detectors with the efficiency e = 0.331 ± 0.026. A method for direct measurement of the background from the chain of reactions T(4He, 4He)T→T(T, 2n)X→(n, γ) and/or (n, n′γ) which ends by neutron activation of materials surrounding the target is proposed and implemented in this study. The value of the astrophysical S-factor of the reaction T(4He, γ)7Li S αt (E cm = 15.7 keV) = 0.091 ± 0.032 keV b provides the choice from the set of experimental data for the astrophysical S αt -factor in favor of experimental data [4] with S αt (E cm = 0) = 0.1067 ± 0.0064 keV b.

Within the standar dmodel of Big Bang Nucleosynthesis (BBN), there is a cosmological lithium problem, which consists in a substantial difference between calculated data on the abundances of the isotopes 6Li and 7Li and those that were found from observational astronomy. An attempt at measuring the cross section for the main 6Li production reaction 2H(4He, γ)6Li induced by the interaction of 4He+ ions with deuterons at collision energies less than the lower boundary of the BBN energy range was made in the present study. Upper limits on the cross sections for the reaction in question were set.

Perylene derivatives with chlorine atoms attached at the bay position to the dye core are expected to affect organisation and tendency to aggregation in Langmuir and Langmuir–Blodgett (LB) films. Therefore, newly synthesized core–twisted homologous series of tetrachloroperylene tetracarboxylic acid esters with n = 1,4,5,6,9 carbon atoms in terminal alkyl chains were studied. Phase transitions and crystalline structures were specified by differential scanning calorimetry (DSC) and single crystal X–ray diffraction (XRD), respectively. Intermolecular interactions and organisation of the dyes in monomolecular films were investigated by means of Brewster angle microscope (BAM), UV–Vis absorption and emission spectroscopy, fluorescence microscopy and atomic force microscopy (AFM). The dyes investigated do not form thermotropic mesogenic phases in bulk. The crystalline triclinic elementary cell with P–1 symmetry is revealed from X–ray experiments. In Langmuir and Langmuir–Blodgett films molecular tilted head–on alignment is postulated. Spectroscopic research confirmed by AFM texture images of the LB films show that in the Langmuir and LB films the dyes, depending on length of terminal chains, have a tendency to create H or I molecular aggregates. The impact of the twisted core on the molecular behavior in a bulk and thin films is discussed.

A homologous series of chiral three ring esters were synthesised and their properties were studied. The materials possess an antiferroelectric phase (SmCA*) or/and a ferroelectric phase (SmC*), which was confirmed by observations of microscopic textures using a polarising optical microscope. The phase transition temperatures and enthalpies were checked by differential scanning calorimetry. The helical pitch was measured by a spectrophotometry method. For all cases the helix is right-handed, in the antiferroelectric phase the helical pitch increases with temperature, and in the ferroelectric phase the helical pitch is short.

The cosmological lithium problem, that is, a noticeable discrepancy between the predicted and observed abundances of lithium, is in conflict with the Standard Big Bang Nucleosynthesis model. For example, the abundance of 7Li is 2–4 times smaller than predicted by the Standard Big Bang Nucleosynthesis. As to the abundance of 6Li, recent more accurate optical investigations have yielded only the upper limit on the 6Li/7Li ratio, which makes the problem of 6Li abundance and accordingly of disagreement with the Standard Big Bang Nucleosynthesis predictions less acute. However, experimental study of the D(4He, γ)6Li reaction cross section is still of current importance because there is a theoretical approach predicting its anomalously large value in the region of energies below the Standard Big Bang Nucleosynthesis energy. The work is dedicated to the measurement of the cross section for the D(4He, γ)6Li reaction proceeding in zirconium deuteride at the incident 4He+ion energy of 36 keV. The experiment is performed at a pulsed Hall plasma accelerator with an energy spread of 20% FWHM. A method for direct measurement of the background from the reaction chain D(4He, 4He)D→D(D, n)3He→(n, γ) and/or (n, n′γ) ending with activation of the surrounding material by neutrons is proposed and implemented in the work. An upper limit on the D(4He, γ)6Li reaction cross section σ≤7·10−36 cm2 at the 90% confidence level is obtained.

The cross section of the reaction D(4He, γ)6Li with titanium and zirconium deuterides as targets is measured for incident 4He+ ion energies of 30 and 36 keV, respectively. The ion beam is generated by a Hall pulsed plasma accelerator. For the first time, upper limits on the cross section of the reaction D(4He, γ)6Li at ultralow energies are imposed (at 90% confidence level): σ ≤ 1.2 × 10−35 cm2 for the TiD2 target and E(4He+) = 30 keV, and σ ≤ 7 × 10−36 cm2 for the ZrD2 target and E(4He+) = 36 keV

Methods for depositing thin layers of deuterides TiD 2 , ZrD 2 , NbD, and CrD 2 on stainless steel substrates are described. Magnetron sputtering of nanolayers of the above deuterides with different textures is considered. A technology for making titanium, zirconium, niobium, and chromium deuteride targets is proposed, which will definitely verify the hypothesis of the enhancement of the dd and pd reactions due to the channeling of the deuterons in the crystals of the above deuterides.

Various methods for depositing thin layers of deuterides (hydrides) TiD2 (TiH2), ZrD2 (ZrH2), NbD (NbH), and CrD2 (CrH2) on stainless steel, copper, and silicon substrates are described. The method for magnetron sputtering of nanolayers of these deuterides (hydrides) with various textures is considered. A technology for producing titanium, zirconium, niobium, and chromium deuteride (hydride) targets is proposed, which will allow the hypothesis of dd and pd reaction enhancement through the channeling of deuterons (protons) in crystals of these deuterides to be unambiguously tested.

Investigation of the pd-and dd-reactions in the ultralow energy (~keV) range is of great interest in the aspect of nuclear physics and astrophysics for developing of correct models of burning and evolution of stars. This report presents compendium of experimental results obtained at the pulsed plasma Hall accelerator (TPU, Tomsk). Most of those results are new, such as • temperature dependence of the neutron yield in the D(d, n)3He reaction in the ZrD2, Ta2D, TiD2 • potentials of electron screening and respective dependence of astrophysical S-factors in the dd-reaction for the deuteron collision energy in the range of 3–6 keV, with ZrD2, Ta2D temperature in the range of 20–200°C [1] • characteristics of the reaction d(p, γ)3He in the ultralow collision proton-deuterons energy range of 4-13 keV [2, 3] in ZrD2, Ta2D and TiD2 • observation of the neutron yield enhancement in the reaction D(d, n)3He at the ultralow deuteron collision energy due to channeling of deuterons in microscopic TiD2 with a face-centered cubic lattice type TiD1.73, oriented in the [100] direction [4]. The report includes discussion and comparison of the collected experimental results with the global data and calculations.

The synthesis, mesomorphic and physical properties of 14 homologous series of laterally fluorinated 4ʹ-alkyl-4-isothiocyanatoterphenyls were described. Influence of the number of fluorine atoms and their position in the terphenyl core on the phase transition temperatures, nematic range, dielectric and optic anisotropy as well as bulk viscosity were discussed. The compounds with the most optimal properties for formulation of nematic mixtures were selected, and mixture examples with low viscosity and medium or high birefringence were presented.

This work is dedicated to measuring the dependences of the effective cross section and the astrophysical S factor for the pd reaction that proceeds in zirconium deuteride upon the proton-deuteron collision energy within a range of 6.0–23.3 keV. The experiment was performed using the heavy-current plasma Hall accelerator at the National Research Tomsk Polytechnic University. The gamma quanta produced in the pd reaction with the energy of 5.5 MeV was recorded using eight scintillation spectrometers based on NaI(Tl) crystals (400 × 100 × 100 mm), which were located around the target. The result of this work coincides with the result of our previous work obtained within a range of proton-deuteron collision energies of 7.3–12.7 keV and agrees well with the result obtained by the LUNA collaboration with the use of the gaseous deuterium target.

In this study, an innovative method is presented for preparing optical fibers for application in fiber optic sensors operating in harsh environments. It is shown, how to attach a metal-coated fiber electrolytically to a metal sensing element, as well as an electroless method for depositing a nickel protective layer on optical fibers. Additionally, the results of the reliability tests of these methods are presented. It is also shown, that by depositing an additional nickel protective layer, it is possible to slow down the oxidation process of the copper coating. Analysis of the conducted experiments allows us to predict, that the connection method investigated and the method of protecting the fiber are robust and may find application in industrial optical sensors.

Zusammenfassung: Ein 54-jähriger Mann stellte sich mit seit 6Wochen bestehender chronischer Diarrhö und einem Gewichtsverlust von 11kg nach Thailandaufenthalt vor. Es lag eine dem Patienten seit 9Jahren bekannte, bisher nicht behandelte und fortgeschrittene HIV-Erkrankung vor. Die Therapie einer im Verlauf diagnostizierten Shigellose und Strongyloidose führte zu keiner Symptombesserung. Nach Koloskopie wurde schließlich eine Zytomegalieviruskolitis diagnostiziert. Unter antiretroviraler Therapie und Therapie mit Valganciclovir kam es schnell zu einer Befundbesserung. Als weitere opportunistische Erkrankung wurde eine multiresistente pulmonale Tuberkulose nachgewiesen.

Syntheses, mesogenic and dielectric properties of three-ring alkylcyclohexyl, alkoxy and alkylphenyl benzoates substituted with four fluorine atoms or with two fluorine atoms and simultaneously a cyano group or two cyano groups are described. Their properties are compared with analogous three-ring phenyl tolanes. Conformation analysis and the calculation of dipole moments with the quantum chemistry method are performed to explain the experimental results. Several four fluorine-substituted two-ring tolanes and biphenyls are also prepared, which are used as a solvent decreasing viscosity, melting point and clearing point of the formulated mixtures. Examples of mixtures prepared from the esters and tolanes with high dielectric anisotropy are given. Curiosity is observed that 4ʹ-(4-ethoxyphenyl)-4-pentyloxy-2,2ʹ,3,3ʹ-tetrafluorotolane is not the mesogenic compound, while analogous ester 4ʹ-ethoxy-2,3-difluorobiphenyl-4-yl 2,3-difluoro-4-pentyloxybenzoate exhibits a broad temperature range of the nemat...

Energy dependence of the neutron yield from the d ( d , n ) 3 He reaction in a textured target of titanium deuteride with predominant [1 0 0] orientation of microcrystals is investigated. The measurements were performed for the incident deuteron energies ranging from 7 to 12 keV in the laboratory coordinate system. It is shown that the energy dependence of the enhancement factor is described not only by the screening potential but also by simply taking account of channeling effects.

Characteristics of the pd reaction (p + d → 3He + γ(5.5 MeV)) in titanium deuteride at astrophysical proton-deuteron collision energies ranging from 5.3 to 10.5 keV are investigated. Experiments are conducted on the pulsed plasma Hall accelerator at Tomsk Polytechnic University (Tomsk, Russia). The number of accelerated protons in a pulse 10 μs long is 5 × 1014 at a repetition rate of 7 × 10−2 Hz. Gamma rays with an energy of 5.5 MeV are recorded by eight detectors based on NaI(Tl) crystals (100 × 100 × 400 mm) arranged around the TiD target. The dependence of the astrophysical S factor for the pd reaction on the proton-deuteron collision energy and the electron screening potential of protons interacting with deuterons in titanium deuteride are measured for the first time.

The article is devoted to the investigation of a pd-reaction (p + d → 3He + γ(5.5 MeV)) under-going in titanium deuteride in astrophysical collision energy region of protons and deuterons ranging from 5.3 to 10.5 keV. The experiments have been performed using the Hall NR TPU (Tomsk, Russia) pulsed plasma accelerator. The number of accelerated protons in 10 μs pulse was 5 × 1014 at a repetition rate of 7 × 10−2 Hz. Detection of 5.5 MeV gamma rays was carried out using eight detectors based on crystals of NaI(Tl) (100 × 100 × 400 mm) placed around the TiD target. For the first time, the dependencies between the astrophysical S-factor and the effective cross section of the pd-reaction from proton-deuteron collision energy, and the potential electronic screening of the interacting protons and deuterons in titanium deuteride have been measured.

The article is devoted to the investigation of a pd -reaction ( p + d → 3 He+ γ (5.5 MeV)) undergoing in titanium deuteride in astrophysical collision energy region of protons and deuterons ranging from 5.3 to 10.5 keV. The experiments have been performed using the Hall NSR TPU (Tomsk, Russia) pulsed plasma accelerator. The number of accelerated protons in 10 μs pulse was 5×10 14 at a repetition rate of 7×10 −2 Hz. Detection of 5.5 MeV gamma rays was carried out using eight detectors based on crystals of NaI(Tl) (100×100×400 mm) placed around the TiD target. For the first time, the dependencies between the astrophysical S -factor and the effective cross-section of the pd -reaction from proton to deuteron collision energy, and the potential electronic screening of the interacting protons and deuterons in titanium deuteride have been measured.

The energy dependence of the neutron yield in the d(d, n)3 He reaction proceeding in a textured titanium deuteride target with the preferred orientation of microcrystals in the [100] direction has been studied. Measurements have been performed for the energy range of incident deuterons of 7–12 keV in the laboratory system. It has been shown that the energy dependence of the enhancement factor of the reaction is described not only by the screening potential but also by the simple inclusion of channeling effects.

The present paper is dedicated to the study of the p(d, γ)3He reaction mechanism with the use of a zirconium deuteride target at proton energies of 11–19 keV. The experiment has been carried out using a proton beam of a high-current pulsed Hall accelerator at the National Research Tomsk Polytechnic University. The dependences of the astrophysical S factor and the effective cross section of the pd reaction on the proton-deuteron collision energy are measured. The results were compared with the available data. The results detailed in the present work agree with the results of an experiment carried out by the LUNA collaboration with the use of a gaseous deuterium target.

It is well known that being an ideal (left ideal, right ideal) of a ring is not a transitive relation. Nevertheless in some cases the transitive property does hold. Systematic studies of this subject were started in [11,13]. In this paper we continue these studies.

The present paper is devoted to the study of the electron screening effect influence on the rate of d ( d , n ) He 3 reaction in the ultralow deuteron collision energy range in the deuterated metals (ZrD 2 , TiD 2 and TaD 0.5 ). The ZrD 2 , TiD 2 and TaD0.5 targets were fabricated via magnetron sputtering of titanium, zirconium and tantalum in gas (deuterium) environment. The experiments have been carried out using the high-current pulsed Hall plasma accelerator (NSR TPU, Russia). The detection of neutrons with energy of 2.5 MeV from the dd reaction was done with plastic scintillation spectrometers. As a result of the experiments, the energy dependences of the astrophysical S -factor for the dd reaction in the deuteron collision energy range of 2–7 keV and the values of the electron screening potential U e of the interacting deuterons have been measured for the above targets: U e ( ZrD 2 ) = ( 205 ± 35 ) eV ; U e ( TiD 2 ) = ( 125 ± 34 ) eV ; U e ( TaD 0.5 ) = ( 313 ± 58 ) eV . Our results are compared with the other published experimental and calculated data.

The temperature dependence of the enhancement factor for the dd reaction proceeding in TiD2 and ZrD2 is investigated. The experiments were carried out at the Hall pulsed ion accelerator (INP, Polytechnic University, Tomsk, Russia) in the deuteron energy interval 7.0–12.0 keV and at temperatures ranging from 20 to 200°C. The values obtained for the electron screening potentials indicate that the dd reaction enhancement factor does not depend on the target temperature in the range 20–200°C. This result contradicts the conclusions drawn by the LUNA Collaboration from their work.

The aim of our research was the preparation of a family of 4'-(ω-perfluoroalkanoyloxy)alkoxybiphenyl-4-yl (S)-4-(1-methylheptyloxy)benzoates smectic liquid crystals. The synthesis has been designed in search of new compounds with a high-tilted smectic C* phase. Five homologous series of chiral esters have been obtained. Phase transition temperatures and enthalpies for all compounds, as well as tilt angle, spontaneous polarisation, helical pitch and layer thickness for some, have been measured. The shapes of the molecules were also simulated. Relationships between the chemical structure and the observed physical and chemical properties are discussed. Unexpectedly, the compounds show a low-tilt smectic C* phase, and sometimes also a smectic C*A phase; an explanation of this feature is given.

The paper is devoted to study electron screening effect influence on the rate of d(d, n)3He reaction in the ultralow deuteron collision energy range in the deuterated polyethylene (CD2), frozen heavy water (D2O) and deuterated metals (ZrD2 and TiD2). The ZrD2 and TiD2 targets were fabricated via magnetron sputtering of titanium and zirconium in gas (deuterium) environment. The experiments have been carried out using high-current plasma pulsed accelerator with forming of inverse Z pinch (HCEIRAS, Russia) and pulsed Hall plasma accelerator (NPI at TPU, Russia). The detection of neutrons with energy of 2.5MeV from dd reaction was done with plastic scintillation spectrometers. As a result of the experiments the energy dependences of astrophysical S factor for the dd reaction in the deuteron collision energy range of 2–7 keV and the values of the electron screening potential U e of interacting deuterons have been measured for the indicated above target: U e (CD2) ⩽ 40 eV; U e (D2O) ⩽ 26 eV; U e (ZrD2) = 157 ± 43 eV; U e (TiD2) = 125±34 eV. The value of astrophysical S factor, corresponding to the deuteron collision energy equal to zero, in the experiments with D2O target is found: S b (0) = 58.6 ± 3.6 keV b. The paper compares our results with other available published experimental and calculated data.

The synthesis and properties of a few dozen highly evolved analogues of (S)-MHPOBC are reported. The liquid crystal phases, and phase transition temperatures and enthalpies, as evidenced by polarized optical microscopy and differential scanning calorimetry, respectively, are given. The helical pitch in pure compounds and some mixtures is estimated using the selective reflection method. All of the compounds show antiferroelectric phases, and some key structure–property relationships for the new materials are reported. Specifically, it is found that the length of the oligomethylene segment of a novel partially fluorinated alkoxy ether tail incorporated into the structures strongly influences the stability of the antiferroelectric phase and the observed phase sequences, as well as the values of the helical pitch and its temperature dependence. The formulation of a family of broad temperature range eutectic mixtures possessing the highly desirable orthoconic antiferroelectric phases with long helical pitch is described.

The syntheses and mesomorphic properties of 4-alkylcyclohexyl- and 4-alkylcyclohexylethyl and 4-alkylbicyclohexyl-3-fluoro- and 3,5-difluorobiphenyl-4-isothiocyanates are described. The compounds are low melting, very broad range nematic liquid crystals and are very useful for the formulation of nematic mixtures of low viscosity and with a moderately high birefringence (0.3–0.35). The refractive indices, bulk viscosity and dielectric anisotropy extrapolated from Demus' ester mixture for the prepared compounds are presented.

This work is devoted to measuring of the values of the astrophysical S-factors and electron screening potential energy for a d(d,n)3He reaction occurring at ultralow energies in zirconium deuteride ZrD2 (3.5–7.0 keV) and heavy water D2O (2.2–6.0 keV). The experiment was performed on the Hall pulsed plasma accelerator at the TPU Nuclear Physics Institute (Tomsk) with ZrD2 and D2O targets produced by the magnetron sputtering of zirconium in a deuterium environment and heavy water freezing-out on a copper support, respectively. A χ2 analysis of the dependence of the neutron yields and astrophysical S-factors for the dd reaction on the deuteron collision energy E revealed that the upper bounds of the electron screening potential energy for interacting deuterons in ZrD2 and D2O and of the astrophysical S-factors at the deuteron collision energy E = 0 were Ue(ZrD2) < 30 eV, Ue(D2O) < 25 eV, S(0) = (57.2 ± 3.9) keV · b (ZrD2), S(0) = (58.6 ± 3.6) keV · b (D2O) at the 90% confidence level.

We present new results on astrophysical S-factors and cross sections for reactions dd → 3He + n(2.5MeV) and pd → 3He + γ (5.5MeV) in ultra-low energy ranges 2.3–6.2 keV and 8.3–10.1 keV, respectively. Experiments were performed with proton and neutron beams produced by a pulsed Hall accelerator (Nuclear Physics Institute, Tomsk) and deuterated polyethylene (CD2) and frozen heavy water (D2O) targets. Within measurement errors, our results are consistent with the literature’s experimental results on pd and dd reactions for the given energy ranges, where D2O or gaseous deuterium targets were used.

Laterally substituted by fluorine atoms 4-cyanophenyl 4-(4-pentylbenzoyloxy)-benzoates have been prepared and their phase transition temperatures, enthalpies and dielectric properties upon frequency were evaluated. The novel compounds exhibit a broad range of nematic mesophase, large positive dielectric anisotropy changing sign at low frequency. They are convenient components of LC mixtures for dual frequency addressing devices.

The pd reaction at ultra-low proton–deuteron collision energies has been studied using the Hall pulsed ion accelerator and the solid target of heavy water D2O. The experiment on measurement of the astrophysical S pd factor and the pd reaction cross-section was carried out at average pd collision energies 8.28, 9.49, and 10.10 keV. The 5.5-MeV γ rays from the pd reaction were detected by detectors based on plastic scintillators and NaI(Tl) crystals. Parameters of the accelerated hydrogen ion flux were measured and monitored with diagnostic equipment consisting of an energy analyzer, plasma optical radiation detectors, the Rogovsky belt, and collimated Faraday cups. The results obtained agree within the errors with the data of the pd experiments carried out by the LUNA collaboration at the Gran Sasso Laboratory with a target filled with gaseous deuterium. The reported experiment was carried out at the Hall ion accelerator of the Research Institute of Nuclear Physics, Tomsk Polytechnic University.

This paper presents the final results of an experimental study of the kinetics of the muon catalysed fusion (MCF) in solid hydrogen-deuterium mixtures (H/D) at a temperature of 3 K. The experiment E742 was carried out on a TRIUMF meson facility in Canada. Four exposures were performed at different deuterium concentrations in the H/D mixture: cd = 0.0005, 0.02, 0.15 and 0.75. A simultaneous analysis of the measured time distributions of the 5.5 MeV γ-quanta and the 5.3 MeV conversion muons obtained from nuclear fusion in the pdμ molecule allowed to extract the values of MCF chain parameters in the H/D mixture: the fusion partial rates for different nuclear spin states of the pdμ molecule, and the pdμ molecule formation rate. The experimental data fitting procedure was conducted in two ways: using solely the analytical formulae describing the kinetics of the MCF processes in the H/D mixture, and the detailed Monte Carlo simulation of the entire experiment. The results obtained by these two methods are consistent with each other and confirm the existence of the Wolfenstein-Gerstein effect.

A 54-year-old man presented with a 6-week history of chronic diarrhea and weight loss of 11 kg after returning from a holiday in Thailand. The patient had a 9-year history of an untreated HIV infection. Despite treatment of a culture-proven Shigella enteritis and strongyloidiasis the symptoms persisted. Finally, cytomegalovirus (CMV) colitis was diagnosed by colonoscopy. The patient recovered completely after starting antiretroviral and valganciclovir treatment. An additional opportunistic infection with multiresistant pulmonary tuberculosis was diagnosed.