bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of a miniaturized duoplasmatron ion source
Authors: Kuzumi Tatsuya , Wada Motoi
Published: January 2020

A miniature sized duoplasmatron ion source mountable on a standard 34 mm diameter copper gasket flange was designed, and its performance was tested. A hollow cathode exited a stable discharge in the anode through a 3 mm diameter orifice of the intermediate electrode with less than 10 W discharge power for Ar. The extracted ion beam current was larger at a smaller discharge current and was maximum at 5 mA below, where the discharge became unstable. A Faraday cup located 200 mm downstream of the extractor detected 1 µA beam current at 5 mA discharge current with 390 V discharge voltage and 2 kV extraction potential. The source required higher discharge voltage for operation of hydrogen gas.
Positive electronic exchange interaction and predominance of minor triplet channel in CIDNP formation in short lived charge separated states of D-X-A dyads
Authors: Zhukov Ivan , Fishman Natalya , Kiryutin Alexey , Lukzen Nikita , Panov Mikhail , Steiner Ulrich , Vieth Hans-Martin , Schäfer Julian , Lambert Christoph , Yurkovskaya Alexandra
Published: January 2020

Previous transient absorption measurements using the magnetically affected reaction yield (MARY) technique for a series of rigidly linked electron donor/electron acceptor dyads (D-X-A) consisting of a triarylamine donor, a naphthalene diimide acceptor, and a meta-conjugated diethynylbenzene unit as a bridge had revealed the presence of electronic exchange interaction, J, in the photoexcited charge separated (CS) state. Here, we present results obtained by photochemically induced dynamic nuclear polarization (photo-CIDNP) that allows for determining the sign of J. By variation of the magnetic field from 1 mT to 9.4 T, pronounced absorptive maxima of CIDNP were detected for more than 20 1H nuclei disregarding the sign of their hyperfine coupling constants in the transient charge separated state, with positions of maxima close to those found by the MARY technique. Quantitative comparison of the observed CIDNP signals for various D-X-A dyads reveals an increase in the CIDNP enhancement factor with increasing population of the triplet state determined by MARY spectroscopy at zero magnetic field. For CIDNP of the methyl groups of the TAA donor dyads, we found in all studies a good linear dependence between the CIDNP signal amplitude and the initial population of the CS triplet state. The linear relationship together with the absorptive CIDNP allows us to conclude that (i) the sign of the electronic exchange interaction Jex is positive, (ii) CIDNP is formed predominantly in the vicinity of level anticrossing between the T+ and S electronic levels, and (iii) coherent triplet-singlet transitions are induced by hyperfine interaction and accompanied by simultaneous electron and nuclear spin flip, T+β→Sα.
Transition to chaos in the cylinder wake through the Mode C flow
Authors: Jiang Hongyi , Cheng Liang
Published: January 2020

The evolution of Mode C wake characteristics with the Reynolds number (Re) for Re up to 400 is investigated numerically. The Mode C wake instability is generated by placing a small wire in the near wake of a main circular cylinder. This setup ensures that the wake is unstable to Mode C only (without potential mode interactions), as demonstrated by Floquet stability analysis. Based on three-dimensional direct numerical simulations, three evolution regimes are identified for the fully developed Mode C flow. In the uniform periodic regime (Re = 166.4–210), the Mode C structure is uniformly distributed along the spanwise direction. The flow structure is 2T-periodic (T being the vortex shedding period) but retains a spatiotemporal symmetry every 1T. In the nonuniform periodic regime (Re = 220–230), the slightly nonuniform Mode C structure remains 2T-periodic at Re = 220 but undergoes a period quadrupling to 4T-periodic at Re = 230 before transitioning to chaos. In the chaotic regime (Re ≥ 240), the flow loses periodicity and becomes increasingly chaotic with increasing Re. The progressive wake transition to chaos is found to originate from the instability in the braid shear layer region through the uneven growth in strength and the consequent nonuniformity of the Mode C streamwise vortices. The wake transitions to chaos through the routes of Mode C and Mode B (for an isolated circular/square cylinder) are compared.
Photodissociation of HCl in the photon energy range 14.6–15.0 eV: Channel-resolved branching ratios and fragment angular distributions
Authors: Wang Lingxuan , Mo Yuxiang
Published: January 2020

For the HCl molecule, four photodissociation channels are open in the excitation energy region 14.6–15.0 eV: H(2s) + Cl(2P3/2), H(2p) + Cl(2P3/2), H(2s) + Cl(2P1/2), and H(2p) + Cl(2P1/2). We measured the fragment angular distributions and the branching ratios of the four dissociation channels by using the extreme ultraviolet laser pump and UV laser probe, delay-time-curve, and velocity map imaging methods. The channel-resolved fragment angular distributions and fragment yield spectra show that various Rydberg states (superexcited states) contribute to the absorption cross sections, including the [A2Σ+]4pσ, [A2Σ+]4pπ, [A2Σ+]3dσ, [A2Σ+]3dπ, and [A2Σ+]5sσ states. Most of the H(2s) + Cl(2P1/2) channels correlate with the 1Σ+ states, while the other channels correlate with mixing excitations of the 1Σ+ and 1,3Π states. The channel branching ratios are dependent on the excitation energies. When the four channels are open, the channel branching ratios of H(2s) + Cl(2P3/2) and H(2p) + Cl(2P1/2) are small. Based on the recent ab initio potential energy curves, the Rydberg states converging to the ion-core A2Σ+ are proposed to be predissociated by the nuclear vibrational continua of the Rydberg states converging to the ion-core X2Π.
The role of saltwater and waves in continental shelf formation with seaward migrating clinoform
Authors: Iwasaki Toshiki , Parker Gary
Published: January 2020

Continental shelves have generally been interpreted as drowned coastal plains associated with the allogenic effect of sea-level variation. Here, without disputing this mechanism we describe an alternative autogenic mechanism for subaqueous shelf formation, driven by the presence of dissolved salt in seawater and surface waves. We use a numerical model describing flow hydrodynamics, sediment transport, and morphodynamics in order to do this. More specifically, we focus on two major aspects: 1) the role of saltwater in the subaqueous construction of continental shelves and 2) the transformation of these shelves into seaward-migrating clinoforms under the condition of repeated pulses of water and sediment input and steady wave effects, but no allogenic forcing such as sea-level change. In the case for which the receiving basin contains fresh water of the same density as the sediment-laden river water, the hyperpycnal river water plunges to form a turbidity current that can run out to deep water. In the case for which the receiving basin contains sea water but the river contains sediment-laden fresh water, the hypopycnal river water forms a surface plume that deposits sediment proximally. This proximate proto-shelf can then grow to wave base, after which wave-supported turbidity currents can extend it seaward. The feature we refer to is synonymous with near-shore mud belts.
Early childhood deprivation is associated with alterations in adult brain structure despite subsequent environmental enrichment
Authors: Mackes Nuria K. , Golm Dennis , Sarkar Sagari , Kumsta Robert , Rutter Michael , Fairchild Graeme , Mehta Mitul A. , Sonuga-Barke Edmund J. S. ,   on behalf of the ERA Young Adult Follow-up team, Sonuga-Barke Edmund , Kennedy Mark , Kreppner Jana , Knights Nicky , Kumsta Robert , Maughan Barbara , Schlotz Wolff
Published: January 2020

Significance

Millions of children worldwide live in nonfamilial institutions. We studied impact on adult brain structure of a particularly severe but time-limited form of institutional deprivation in early life experienced by children who were subsequently adopted into nurturing families. Institutional deprivation was associated with lower total brain volume in a dose-dependent way. Regionally specific effects were seen in medial prefrontal, inferior frontal, and inferior temporal areas. Deprivation-related alterations in total brain volume were associated with lower intelligence quotient and more attention deficit/hyperactivity disorder symptoms; alterations in temporal volume seemed compensatory, as they were associated with fewer attention deficit/hyperactivity disorder symptoms. We provide evidence that early childhood deprivation is related to alterations in adult brain structure, despite environmental enrichment in intervening years.
High productivity in hybrid-poplar plantations without isoprene emission to the atmosphere
Authors: Monson Russell K. , Winkler Barbro , Rosenstiel Todd N. , Block Katja , Merl-Pham Juliane , Strauss Steven H. , Ault Kori , Maxfield Jason , Moore David J. P. , Trahan Nicole A. , Neice Amberly A. , Shiach Ian , Barron-Gafford Greg A. , Ibsen Peter , McCorkel Joel T. , Bernhardt Jörg , Schnitzler Joerg-Peter
Published: January 2020

Hybrid-poplar tree plantations provide a source for biofuel and biomass, but they also increase forest isoprene emissions. The consequences of increased isoprene emissions include higher rates of tropospheric ozone production, increases in the lifetime of methane, and increases in atmospheric aerosol production, all of which affect the global energy budget and/or lead to the degradation of air quality. Using RNA interference (RNAi) to suppress isoprene emission, we show that this trait, which is thought to be required for the tolerance of abiotic stress, is not required for high rates of photosynthesis and woody biomass production in the agroforest plantation environment, even in areas with high levels of climatic stress. Biomass production over 4 y in plantations in Arizona and Oregon was similar among genetic lines that emitted or did not emit significant amounts of isoprene. Lines that had substantially reduced isoprene emission rates also showed decreases in flavonol pigments, which reduce oxidative damage during extremes of abiotic stress, a pattern that would be expected to amplify metabolic dysfunction in the absence of isoprene production in stress-prone climate regimes. However, compensatory increases in the expression of other proteomic components, especially those associated with the production of protective compounds, such as carotenoids and terpenoids, and the fact that most biomass is produced prior to the hottest and driest part of the growing season explain the observed pattern of high biomass production with low isoprene emission. Our results show that it is possible to reduce the deleterious influences of isoprene on the atmosphere, while sustaining woody biomass production in temperate agroforest plantations.
Water level changes, subsidence, and sea level rise in the Ganges–Brahmaputra–Meghna delta
Authors: Becker Mélanie , Papa Fabrice , Karpytchev Mikhail , Delebecque Caroline , Krien Yann , Khan Jamal Uddin , Ballu Valérie , Durand Fabien , Le Cozannet Gonéri , Islam A. K. M. Saiful , Calmant Stéphane , Shum C. K.
Published: January 2020

Significance

This work provides a robust estimate of water-level (WL) changes in the Ganges–Brahmaputra–Meghna delta, driven by continental freshwater dynamics, vertical land motion, and sea-level rise. Through an unprecedented set of 101 gauges, we reconstruct WL variations since the 1970s and show that the WL across the delta increased slightly faster, ∼3 mm/y, than the global mean sea-level rise (∼2 mm/y). By combining satellite altimetry and WL reconstructions, we estimate that maximum expected rates of delta subsidence since the 1990s range from 1 to 7 mm/y. By 2100, even under a greenhouse gas emission mitigation scenario (RCP4.5), the subsidence could double the projected sea-level rise, making it reach 85 to 140 cm across the delta.
Large-scale contractions of Friedreich’s ataxia GAA repeats in yeast occur during DNA replication due to their triplex-forming ability
Authors: Khristich Alexandra N. , Armenia Jillian F. , Matera Robert M. , Kolchinski Anna A. , Mirkin Sergei M.
Published: January 2020

Significance

Expansions of GAA repeats cause a severe hereditary neurodegenerative disease, Friedreich’s ataxia. In this study, we characterized the mechanisms of GAA repeat contractions in a yeast experimental system. These mechanisms might, in the long run, aid development of a therapy for this currently incurable disease. We show that GAA repeats contract during DNA replication, which can explain the high level of somatic instability of this repeat in patient tissues. We also provided evidence that a triple-stranded DNA structure is at the heart of GAA repeat instability. This discovery highlights the role of triplex DNA in genome instability and human disease.
Intermediate states of molecular self-assembly from liquid-cell electron microscopy
Authors: Wang Huan , Li Bo , Kim Ye-Jin , Kwon Oh-Hoon , Granick Steve
Published: January 2020

Significance

Graphene liquid-cell electron microscopy reveals intermediate states of self-assembly—in this example, DNA when single strands form double helices. Molecules are observed for up to minutes at a time without apparent beam damage when electron energy and electron dose are low. Simultaneous in situ single-molecule imaging of conformational adaptations and motion gives more comprehensive understanding of self-assembly successes, failures, and error-producing mechanisms, confirming some earlier predictions and also presenting surprises. Loop intermediates were observed to facilitate error correction. Hybridization events accompany enhanced translational mobility and mechanistically specific persistent rotation. The information obtained goes beyond that from other single-molecule methods.
Scientists’ incentives and attitudes toward public communication
Authors: Rose Kathleen M. , Markowitz Ezra M. , Brossard Dominique
Published: January 2020

In an era of large-scale science-related challenges and rapid advancements in groundbreaking science with major societal implications, communicating about science is critical. The profile of science communication has increased over the last few decades, with multiple sectors calling for such activities. As scientists respond to calls for public-facing communication, we need to evaluate where the scientific community stands. We conducted a unique census of science faculty at land-grant universities across the United States intended to spur the next generation of science communicators and research. Despite scientists’ strong approval of science communication efforts, potential areas of tension, attributable to lack of institutional support and confidence in communication skills, constrain these efforts.
Preliminary Systematic Study of the Temperature Effect on the K–Cs–Sb Photocathode Performance Based on the K and Cs Co-Evaporation*
Authors: Li Xu-Dong , Jiang Zeng-Gong , Gu Qiang , Zhao Ming-Hua , Guo Li
Published: January 2020

It is very important to increase the quantum efficiency (QE) and prolong the lifetime of the photocathode in a variety of applications. We have succeeded in preparing a high QE cesium potassium antimonide (K–Cs–Sb) photocathode by K and Cs co-evaporation in the photocathode preparation facility. In order to better understand the effect of the substrate (photocathode) temperature on the photocathode performance, the photocathode preparation, photocathode performance degradation, photocathode performance recovery and photocathode removal are studied in detail.
Instability in Two-Sided Thermocapillary-Buoyancy Convection with Interfacial Phase Change*
Authors: Xu Guo-Feng , Liu Qiu-Sheng , Qin Jun , Zhu Zhi-Qiang
Published: January 2020

A new model of two-phase thermocapillary-buoyancy convection with phase change at gas-liquid interface in an enclosed cavity subjected to a horizontal temperature gradient is proposed, rather than the previous one-sided model without phase change. We study the onset of multicellular convection and two modes of convective instability, and find four different flow regimes. Their transition map is compared with the non-phase-change condition. Our numerical results show the stabilizing effect of interfacial phase change on the thermocapillary-buoyancy convection.
Anomalous lattice stiffening in tungsten tetraboride solid solutions with manganese under compression
Authors: Li Haijing , Tao Qiang , Dong Juncai , Gong Yu , Guo Zhiying , Liao Jiangwen , Hao Xinyu , Zhu Pinwen , Liu Jing , Chen Dongliang
Published: January 2020

Tungsten tetraboride (WB4)-based solid solutions represent one of the most promising superhard metal candidates; however, their underlying hardening mechanisms have not yet been fully understood. Here, we explore the lattice compressibility of WB4 binary solid solutions with different manganese (Mn) concentrations using high-pressure x-ray diffraction (XRD) up to 52 GPa. Under initial compression, the lattices of low and high Mn-doped WB4 alloys (i.e. W0.96Mn0.04B4 and W0.84Mn0.16B4) are shown to be more and less compressible than pure WB4, respectively. Then, a c-axis softening is found to occur above 39 GPa in WB4, consistent with previous results. However, an anomalous sudden a-axis stiffening is revealed at ~36 GPa in W0.96Mn0.04B4, along with suppression of c-axis softening observed in WB4. Furthermore, upon Mn addition, a simultaneous stiffening of a- and c-axes is demonstrated in W0.84Mn0.16B4 at ~37 GPa. Speculation on the possible relationship between this anomalous stiffening and the combined effects of valence-electron concentration (VEC) and atomic size mismatch is also included to understand the origin of the nearly identical hardness enhancement in those two solid solutions compared to WB4. Our findings emphasize the importance of accurate bonding and structure manipulation via solute atoms to best optimize the hardness of WB4 solid solutions.
Semi-device-independent quantum money
Authors: Horodecki Karol , Stankiewicz Maciej
Published: January 2020

The seminal idea of quantum money, not forgeable due to laws of Quantum Mechanics, proposed by Stephen Wiesner, has laid the foundations for the Quantum Information Theory in the early ’70s. Recently, several other schemes for quantum currencies have been proposed, all, however, relying on the assumption that the quantum source device, acts according to its specification. This makes several known quantum money protocols vulnerable to the so-called hardware Trojan horse attacks. We, therefore, study the following problem: to what extent quantum money schemes can be made independent from the inner working of source and verification-devices used by the honest parties (bank and mint) in creating and processing the quantum money? Drawing inspirations from the semi-device-independent quantum key distribution protocol, we introduce the first scheme of quantum money with this assumption partially relaxed, along with the proof of its unforgeability. Finally, we formulate and discuss a quantum analog of the Oresme–Copernicus–Gresham’s law of economy, that may hold in the future.
Measuring von Neumann entanglement entropies without wave functions
Authors: Mendes-Santos T , Giudici G , Fazio R , Dalmonte M
Published: January 2020

We present a method to measure the von Neumann entanglement entropy of ground states of quantum many-body systems which does not require access to the system wave function. The technique is based on a direct thermodynamic study of lattice entanglement Hamiltonians—recently proposed in the paper [Dalmonte et al 2018 Nat. Phys.
14 827] via field theoretical insights—and can be performed by quantum Monte Carlo methods. We benchmark our technique on critical quantum spin chains, and apply it to several two-dimensional quantum magnets, where we are able to unambiguously determine the onset of area law in the entanglement entropy, the number of Goldstone bosons, and to check a recent conjecture on geometric entanglement contribution at critical points described by strongly coupled field theories. The protocol can also be adapted to measure entanglement in experiments via quantum quenches.
Hybrid Rabi interactions with traveling states of light
Authors: Park Kimin , Laurat Julien , Filip Radim
Published: January 2020

Hybrid interactions between light and two-level systems and their nonlinear nature are crucial components of advanced quantum information processing and quantum networks. Rabi interaction (RI) exhibits the hybrid nonlinear nature, but its implementation is challenging at optical frequencies where the rotating wave approximation (RWA) is valid. Here, we propose a setup to conditionally induce RI between discrete variable and continuous variable of traveling beams of light. We show that our scheme can generate RI on weak states of light, where signatures of the nonlinear quantum effects are preserved for typical experimental losses. These results prove that a hybrid RI can be realized in all-optical setups, and open a way to experimental investigations of nonlinear quantum optics beyond RWA.
A universal form of localized complex potentials with spectral singularities
Authors: Zezyulin Dmitry A , Konotop Vladimir V
Published: January 2020

We establish necessary and sufficient conditions for localized complex potentials in the Schrödinger equation to enable spectral singularities (SSs) and show that such potentials have the universal form

U

(
x
)

=
−

w

2

(
x
)

−

i
w

x

(
x
)

+

k

0

2

, where w(x) is a differentiable function, such that

lim

x
→
±
∞

w
(
x
)

=
∓

k

0

, and k
0 is a non-zero real. We also find that when k
0 is a complex number, then the eigenvalue of the corresponding Shrödinger operator has an exact solution which, depending on k
0, represents a coherent perfect absorber (CPA), laser, a localized bound state, a quasi bound state in the continuum (a quasi-BIC), or an exceptional point (the latter requiring additional conditions). Thus, k
0 is a bifurcation parameter that describes transformations among all those solutions. Additionally, in a more specific case of a real-valued function w(x) the resulting potential, although not being




symmetric, can feature a self-dual SS associated with the CPA-laser operation. At this moment, the complex potential has exactly two coexisting SSs at different points of the continuous spectrum. In the space of the system parameters, the transition through each self-dual SS corresponds to a bifurcation of a pair of complex-conjugate propagation constants from the continuum. The bifurcation of a first complex-conjugate pair corresponds to the phase transition from purely real to complex spectrum.
Design of diamond-shape photonic crystal fiber polarization filter based on surface plasma resonance effect*
Authors: Zhang Yongxia , Yuan Jinhui , Qu Yuwei , Zhou Xian , Yan Binbin , Wu Qiang , Wang Kuiru , Sang Xinzhu , Long Keping , Yu Chongxiu
Published: January 2020

A novel plasmonic polarization filter based on the diamond-shape photonic crystal fiber (PCF) is proposed. The resonant coupling characteristics of the PCF polarization filter are investigated by the full-vector finite-element method. By optimizing the geometric parameters of the PCF, when the fiber length is 5 mm, the polarization filter has a bandwidth of 990 nm and an extinction ratio (ER) of lower than –20 dB. Moreover, a single wavelength polarization filter can also be achieved, along with an ER of –279.78 dB at wavelength 1.55 μm. It is believed that the proposed PCF polarization filter
will be very useful in laser and optical communication systems.
Far-field vector-diffraction of off-axis parabolic mirror under oblique incidence*
Authors: Zeng Xia-Hui , Chen Xi-Yao
Published: January 2020

Based on a full vector-diffraction theory, a detailed theoretical study is carried out, aiming at providing a clear insight into the effects of different focusing and off-axis parabola parameters on far-field vector-diffraction properties of an off-axis parabolic mirror in the presence of misalignments of the incoming beam. The physical origin of these effects is also explored. The results show that the far-field intensity profile is altered by the distortion-, coma-, and astigmatism-like aberrations, which are caused by oblique incidence rather than inherent aberrations for the off-axis configuration. The radius of 90% encircled energy also increases but does not change monotonically with incident beam size increasing, or rather, it first decreases and then increases. The focal shift strongly depends on the effective focal length and oblique incidence angle, but it is almost independent of the beam size, which affects the focusing spot patterns. The intensity distribution produces a higher astigmatic image with off-axis angle increasing. Coma-like aberration starts to become dominant with beam size increasing and results in larger curved propagation trajectory. The incident polarization also affects the intensity distribution. The variation in the Strehl ratio with oblique incidence angle strongly depends on the misalignment direction and beam size as well. In addition, we find that the difference in locus between the catacaustic and the diffraction focus in the meridian is small. But the locus of the sagittal foci is obviously different from the locus of the meridian foci and the catacaustic focus. Moreover, the peak intensity of the sagittal focus is maximum, and the ratio of the peak intensity to that in the meridian plane is approximately 1.5. Understanding these effects is valuable for assessing a practical focused intensity and describing the motion of charged particles under a strong electric field in ultraintense laser–matter interaction.
Second harmonic magnetoacoustic responses of magnetic nanoparticles in magnetoacoustic tomography with magnetic induction*
Authors: Guo Gepu , Gao Ya , Li Yuzhi , Ma Qingyu , Tu Juan , Zhang Dong
Published: January 2020

Due to the unique magnetic, mechanical and thermal properties, magnetic nanoparticles (MNPs) have comprehensive applications as the contrast and therapeutic agents in biomedical imaging and magnetic hyperthermia. The linear and nonlinear magnetoacoustic responses determined by the magnetic properties of MNPs have attracted more and more attention in biomedical engineering. By considering the relaxation time of MNPs, we derive the formulae of second harmonic magnetoacoustic responses (2H-MARs) for a cylindrical MNP solution model based on the mechanical oscillations of MNPs in magnetoacoustic tomography with magnetic induction (MAT-MI). It is proved that only the second harmonic magnetoacoustic oscillations can be generated by MNPs under an alternating magnetic excitation. The acoustic pressure of the 2H-MAR is proportional to the square of the magnetic field intensity and exhibits a linear increase with the concentration of MNPs. Numerical simulations of the 2H-MAR are confirmed by the experimental measurements for various magnetic field intensities and solution concentrations using a laser vibrometer. The favorable results demonstrate the feasibility of the harmonic measurements without the fundamental interference of the electromagnetic excitation, and suggest a new harmonic imaging strategy of MAT-MI for MNPs with enhanced spatial resolution and improved signal-to-noise ratio in biomedical applications.
Mass spectra and wave functions of the doubly heavy baryons with JP=1+ heavy diquark cores *
Authors: Li Qiang , Chang Chao-Hsi , Qin Si-Xue , Wang Guo-Li
Published: January 2020

Mass spectra and wave functions of the doubly heavy baryons are computed assuming that the two heavy quarks inside a baryon form a compact heavy ‘diquark core’ in a color anti-triplet, and bind with the remaining light quark into a colorless baryon. The two reduced two-body problems are described by the relativistic Bethe-Salpeter equations (BSEs) with the relevant QCD inspired kernels. We focus on the doubly heavy baryons with

heavy diquark cores. After solving BSEs in the instantaneous approximation, we present the mass spectra and the relativistic wave functions of the diquark cores, and of the low-lying baryon states

and

with flavors

,

and

. A comparison with other approaches is also made.
A holographic description of theta-dependent Yang-Mills theory at finite temperature *
Authors: Li Si-Wen
Published: January 2020

Theta-dependent gauge theories can be studied using holographic duality through string theory in certain spacetimes. By this correspondence we consider a stack of N
0 dynamical D0-branes as D-instantons in the background sourced by N
c coincident non-extreme black D4-branes. According to the gauge-gravity duality, this D0-D4 brane system corresponds to Yang-Mills theory with a theta angle at finite temperature. We solve the IIA supergravity action by taking account into a sufficiently small backreaction of the Dinstantons and obtain an analytical solution for our D0-D4-brane configuration. Subsequently, the dual theory in the large N
c limit can be holographically investigated with the gravity solution. In the dual field theory, we find that the coupling constant exhibits asymptotic freedom, as is expected in QCD. The contribution of the theta-dependence to the free energy gets suppressed at high temperatures, which is basically consistent with the calculation using the Yang-Mills instanton. The topological susceptibility in the large N
c limit vanishes, and this behavior remarkably agrees with the implications from the simulation results at finite temperature. Moreover, we finally find a geometrical interpretation of the theta-dependence in this holographic system.
Antiproton production in heavy-ion collisions at subthreshold energies *
Authors: Feng Zhao-Qing
Published: January 2020

Within the framework of the Lanzhou quantum molecular dynamics model, the deep subthreshold antiproton production in heavy-ion collisions has been investigated thoroughly. The elastic scattering, annihilation and charge exchange reactions associated with antiproton channels are implemented in the model. The attractive antiproton potential extracted from the G-parity transformation of nucleon selfenergies reduces the threshold energies in meson-baryon and baryon-baryon collisions, and consequently enhances the antiproton yields to some extent. The calculated invariant spectra are consistent with the available experimental data. The primordial antiproton yields increase with the mass number of the colliding system. However, annihilation reactions reduce the antiproton production which becomes independent of the colliding partners. Anti-flow phenomena of antiprotons correlated with the mean field potential and annihilation mechanism is found by comparing them with the proton flows. Possible experiments at the high-intensity heavy-ion accelerator facility (HIAF) in China are discussed.
Nonequilibrium processes of power and enviromental resistance of reinforced concrete structures to progressive collapse
Authors: Kolchunov V I , Androsova N B
Published: January 2020

The problems of calculating the parameters of non-equilibrium power and environmental resistance of reinforced concrete elements of a structural system under special effects are considered. A static-dynamic diagram of the deformation of corrosion-damaged concrete during overlimit impact caused by the sudden removal of a supporting structure is constructed. The section of this diagram is described by the analytical dependence for change in the strength of loaded and corrosion-damaged concrete from time, which takes into account, on the one hand, the process of the increasing strength of “healthy” concrete in time (theory of concrete aging), and on the other, the process of the degradation of an aggressive environment on concrete. A section of the dynamic deformation diagram is described by the Kelvin-Voigt model in a version of the theory of plasticity of concrete G.A. Genius, which corresponds to the conditions of deformation of concrete as an elastic-viscous-plastic material. The dynamic tensile strength of corrosion-damaged concrete is taken into account by the coefficient of increase in the dynamic strength of the material based on the two-element model of its deformation.
Measured and forecast settlements of buildings near deep pits in Vietnam
Authors: Nikiforova N S , Van-Hoa Nguyen , Alekseev G V
Published: January 2020

The design and construction of underground facilities in major cities in Vietnam, such as Hanoi and Ho Chi Minh city, have currently been expanded. Digging deep excavation pits for underground spaces or subway stations can lead to settlements of the surrounding buildings. Under the soft soils or water-saturated clay soils, the construction of underground spaces causes additional settlements to the surrounding soil mass. Therefore, it is necessary consider the technological settlement, which is the effect of the construction process of deep excavations, to forecast the total settlement of surrounding buildings. This study proposes an equation to predict the building subsidence due to the influence of deep excavation accounting the technological settlement.
Piled raft foundation assessment based on geotechnical monitoring results
Authors: Gryaznova Elena
Published: January 2020

Article discusses data analysis of geodetic and strain gauge monitoring of stress-strain state of high-rise building foundation. Recommendations are given to improve monitoring system by expanding its analytical component through use of computer modeling, accounting for the work of foundation structure and soil base under gradual increase in number of stories of the building. Monitoring data is compared with results of calculations and design studies. Their qualitative and quantitative convergence is notable. Recommendations are given for further foundations design of high-rise buildings.
Flexural behavior of RC beam strengthened by stay in place SFRC sheet formwork
Authors: Kapustin Dmitriy , Zeid Kilani Leis
Published: January 2020

The paper presents results of experimental and numerical modeling of flexural behavior of RC beam strengthened be stay in place SFRC sheet formwork in a tensioned zone. Analysis of influence of the SFRC on crack propagation. As a result monolithic concrete provides the perception of tensile forces before the formation of main cracks in the steel fiber concrete.
Comparison between Analytical Method and Numerical Model for Footings on Soft Clay Supported by Stone Columns
Authors: Znamenskii V V , Sayed D A
Published: January 2020

The increase in population in many locations and the value of land has increased significantly. This has made the use of all areas including soft problematic soils inevitable. Due to the lack of bearing capacity of these soils, different methods of soil improvement techniques such as stone columns are used. In this study, four different analytical methods published before are briefly motioned. Also, three-dimensional (3D) numerical analyses were carried out on a stone column under footing on the soft clay soil. The main point of the current paper is to make a comparison between a numerical model and different analytical methods to represent a footing on the soft clay soil reinforced by a group of stone columns.
Calculation of the stiffness of reinforced concrete structures under the action of torsion and bending
Authors: Kolchunov V I , Dem’yanov A I , Naumov N V , Mikhaylov M M
Published: January 2020

The development of methods for calculating the stiffness of reinforced concrete structures with cracks at the limit states is an urgent task. The proposed method implies that the spatial cracks develop on special bilinear surfaces. It involves dividing a rectangular section into a series of squares, which are subsequently replaced by the circles inscribed in them. This approach requires the introduction of the concept of “equivalence” between the torsional stiffness characteristics of a rectangular section and the circumscribed circle. The equation for determining the tangential torsional stresses (taking into account the deplanation) at any point of the cross section is written in a cylindrical and Cartesian coordinate system. Two variants of modelling a real crack are proposed: in the form of stepwise located three-dimensional finite elements that are detached in common nodes, or using an imaginary crack along which pairs of finite elements are picked out. So, we use a special double cantilever model for the calculation. Having a picture of the applied force and deformation loads (crack opening) in the console nodes, it is possible to determine the values of the work in the state: “before detach” and “after detach” of the double-element model.
Buckling load of an infinitely long cylindrical shell interacting with the soil environment
Authors: Kosytsyn Sergey , Akulich Vladimir
Published: January 2020

The article considers the problems of numerical computational stability analysis for an infinitely long cylindrical shell interacting with the soil environment. Several spatial computational models of “the shell – the soil” system have been compiled to determine the buckling load and the buckling mode. The interaction of the shell and the soil environment is provided by contact pairs located on the respective surfaces. Contact pairs with a rigid connection between bodies and contact pairs with the detachment possibility of interacting bodies are used. Contact pairs with and without the friction coefficient are also used. The problem is solved in linear and nonlinear statement. The materials of the shell and the soil environment are given by elastic-plastic models of Mohr-Coulomb and Drucker-Prager. The buckling loads are defined relative to the effective gravity load. The buckling loads and the buckling modes of the cylindrical shell are obtained as a result of numerical computational stability analysis. The comparative analysis of the received buckling loads is presented and the corresponding conclusions are given.
The consideration of compliance of structural joints in the numerical calculation of large-panel buildings
Authors: Malakhova A N , Davletbaeva D A
Published: January 2020

The article considers the determination of compliance of vertical joints of wall panels of large-panel buildings made on embedded parts. The simulation of these joints in the calculation model of the structural system of a large-panel building is shown. The algorithm for determining the compliance of vertical joints of wall panels of large-panel buildings is described using the «New displacement program» developed by the authors of this article. The service opportunities of the program for the presentation of calculation results are shown. The comparative results of determining the compliance of wall panels vertical joints using two types of connecting parts are presented, which demonstrates the capabilities of the program to investigate the operation of vertical joints in large-panel buildings with different structural solutions of joints.
3D modeling of supply and exhaust ventilation in the concept of passive building in the software package Autodesk 3ds Max
Authors: Korol O A , Petrov A A , Shreiber K A
Published: January 2020

The main issue of the study is the problem of the possibility and feasibility of 3D modeling, and the use of supply and exhaust systems for heat and moisture recovery in the design of a passive building, using a 2-stage scheme of air heating in climatic and geographical conditions for the city of Kaliningrad. After all, using this mechanical ventilation and air heating scheme in a passive building, it is possible to reduce annual energy costs by 3-4 times. The higher capital costs of a passive building are offset by lower operating costs due to a significant reduction in energy consumption.
Monetary evaluation of the reduced service life of asphalt pavements caused by the interlayer bond
Authors: Hristov B D , Wellner F
Published: January 2020

The sustainability of asphalt pavements is highly depending on the quality of the interlayer bond (IB) between the different asphalt layers. In this project a complicated apparatus for cycling testing of the interlayer bond has been developed in order to determine the shear stiffness at the interface between asphalt layers taking into account the combined effect of varying and repeated traffic loading, acceleration and braking processes and temperature. A universal master function for analytical assessment of the IB shear stiffness has been established for any IB condition using the experimental results. Another function for completely fatigued IB has been developed as well. Both functions have been implemented into a finite element program to estimate the fatigue status of asphalt pavements for different bond qualities over a service life of 30 years using the German method for computational design according to RDO Asphalt 09. It has been succeeded to make a monetary evaluation of the reduced service life of asphalt pavements caused by interlayer bonds of different quality and to assess the construction cost penalty.
Analytical representation for the problem of a loaded hollow layered cylinder taking into account the creep of its layers
Authors: Bobyleva T N , Shamaev A S
Published: January 2020

The paper deals with a cylindrical hollow rod with a layered structure along the radius. Layers consist of isotropic elastic creeping materials. An analytical solution is given for the problem of the stress-strain state of such rod. Tensile and bending stiffness can be presented in analytical form. An algorithm is proposed for constructing an analytical solution to the problem of various loading of a layered rod consisting of elastic-creeping layers in the presence of radial symmetry.
Simulation of free vibrations of a thick plate without simplifying hypotheses
Authors: Usarov Davronbek , Turajonov Kodirjon , Khamidov Saidjon
Published: January 2020

The paper is devoted to the simulation of free vibrations of orthotropic thick plates taking into account internal forces, moments and bimoments. To solve the problem, equations of motion of a plate are built, described by a six-equation system, constructed in the framework of a simplified version of the bimoment theory of thick plates. As an example, consider the problem of determining natural frequencies of thick isotropic and orthotropic fixed plates under transverse vibrations, taking into account the transverse shear and compression along the thickness.
Ultimate stress state of a plate made of orthotropic material under uniform internal pressure
Authors: Blokhina N S
Published: January 2020

The paper regards ultimate stress state of an unbounded plate with a circular opening made of orthotropic material. Unlike isotropic material, this problem is not axisymmetric. The solution to the problem was carried out by an iterative method. As a first approximation, a corresponding problem solution was used, assuming that the radial and tangential stresses are the main ones. The obtained solution is compared with the stress state of the plate, achieved under the assumption that the problem is axisymmetric.
Creation of the information system based on the integrated evaluation of a construction object at various life cycle stages
Authors: Kozhevnikov M M , Ginzburg A V , Kozhevnikova S T
Published: January 2020

This work contains analysis of the problems regarding the development and maintaining of executive documents on the construction, reconstruction and overhaul process. The study considers the following matters: goal-setting for elaborating process of an object operational model; improvement of the construction organization efficiency in order to reduce labor and time costs on executive documentation preparation and processing, as well as to minimize the number of mistakes contained in it.
On one method of finding optimal control in construction industry
Authors: Titova T.
Published: January 2020

In this paper we consider options for solving optimal control problems with a quadratic quality criterion. There are optimal management tasks in the construction industry also. For example, in optimizing the construction technology of large complexes, construction work cycles at the facilities. A quadratic quality criterion leads to Riccati matrix differential equations that are generally not solvable in quadratures. In this paper we consider solution options in the case of a stationary system. We find a symmetric solution of algebraic matrix Riccati equation. We offer some new analytical methods for solving this nonlinear equation in various cases.
Losses in the manufacture of wooden building structures
Authors: Seregin N G
Published: January 2020

Wood properties have successfully established themselves in the building structures. Very important to know expected wood losses in production. Losses are considered throughout the process of woodworking from sawmilling to obtaining glued blank. Research results were an assessment of losses in production of glued window beam as an example and substantiation of recommendations to production of wooden window blocks for choosing the type of primary source material: roundwood or edged sawn timber.
The mathematical model of environmental waters purification
Authors: Skolubovich Yu.L. , Skolubovich A.Y. , Volkov D.D. , Krasnova T.A. , Gogina E.S.
Published: January 2020

This article describes the use of the stochastic approach, in particular, mass service theory and the development of its methods, adapted directly to the coagulation process as a mathematical tool. The coagulation process will be concerned as a) supplying water to the mixer, b) processing it with reagents (coagulants), c) settling for the mathematical analysis of water clarification effectiveness.
Methods and models for building bank branches. A Multicriteria approach for a decision-making tool
Authors: Bellintani S , Celani A , Ciaramella G
Published: January 2020

This work intends to study the latest trends in building branch systems, testing a mathematical model in the Italian banking sector at its current state of art. Particular attention is given to which is the relationship that links evolution, in terms of technology and needs, both of bank and customers, with physical spaces (branches).

The questions that will be possibly answered are: what is the value of a banking branch system and how building strategies can impact on it? How should they be located in the territory? What construction form should they take to adapt to the new needs?

A meta-design has been developed to identify the guidelines to be followed and the interventions to be taken in practice, by simulating a business case that, through the application of a multi criteria analysis, can be a reference for credit institutions. The developed methodology is then applied to a portion of the city of Milan, in order to practically experiment the feasibility and the outcomes.
Exponential stability of the stationary solutions of the kinetic Carleman system
Authors: Dukhnovsky Sergey
Published: January 2020

In this article we discuss the kinetic system of Carleman equations. Research of technological processes for the production of building materials is based on autocatalysis reactions. The Carleman system is a special case of the discrete Boltzmann equation. In many problems of the kinetic theory of gases, gas dynamics, autocatalysis chemistry, and other fields of science and technology, Cauchy problems of hyperbolic equations arise that describe various processes. In the one-dimensional case, the system Carleman describes autocatalysis. A theorem on the stabilization of solutions of the Carleman system is formulated.