bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of the Ship-Borne Multi-Wavelength Polarization Ocean Lidar System and Measurement of Seawater Optical Properties
Authors: Liu Qi , Liu Bingyi , Wu Songhua , Liu Jintao , Zhang Kailin , Song Xiaoquan , Chen Xiangcheng , Zhu Peizhi
Published: July 2020

A ship-borne multi-wavelength polarization ocean lidar system LOOP (Lidar for Ocean Optics Profiler) is introduced in detail, aiming to obtain high-precision vertical profiles of seawater optical characteristics. Based on Monte-Carlo simulation, the receiving telescope is designed with a variable field of view, producing system attenuation coefficient (Klidar) approximating the optical parameters of seawater under a different field of view and water body conditions. At first, a sea trial was conducted in Jiaozhou Bay, and the measured diffuse attenuation coefficient (Kd) of seawater was 0.3m−1, being in good agreement compared with the results measured by field instrument TriOS. Then a field campaign was organized in the South China Sea. The measurement of the seawater diffuse attenuation (Kd) was 0.035m−1. These results support the prospects that lidar, as an effective tool supplement to traditional passive ocean color remote sensing, can provide the vertical distributions of optical properties in the upper ocean.
Development of a Multiple-Field-of-View Multiple-Scattering Polarization Lidar System at 355nm for Cloud Measurements
Authors: Nishizawa Tomoaki , Jin Yoshitaka , Sugimoto Nobuo , Okamoto Hajime , Fujikawa Masahiro , Ishii Shoken
Published: July 2020

We developed a multiple-filed-of view multiple-scattering polarization lidar (MFMSPL) at 355nm to study microphysics of optically thick clouds and understand multiple scattering effects on space lidar measurements (e.g., EarthCARE). This system is based on depolarization Mie lidar technique; it uses a compact receiver module including a small telescope, polarizer, and detectors to measure co-polar and cross-polar backscatter signals, separately. The MFMSPL system has all the 10 measurement channels. The MFMSPL uses the five receiver modules with FOV of 10mrad tilted with different zenith angles (θ); it measures on-beam signals (θ=0mrad) as well as four off-beam signals (θ=10,20,30,40mrad). This MFMSPL system was based on previously developed 532nm MFMSPL system, however, we made the system more stable, robust, and compact by integrating co-polar and cross-polar channels in the receiver module than the previous system. In addition, we improved the dynamic range of the measurement in nighttime by synergy use of analog and photon counting measurements. In the conference, we present the MFMSPL system, data analysis method including calibration method, and observation results.
Exploring the Twilight Zone: A Multi-Sensor Approach
Authors: da Silva Jonatan , Morais Fernando G. , Franco Marco A. , Lopes Fábio J. S. , Arruda Gregori de A. , Yoshida Alexandre C. , Correia Alexandre , Landulfo Eduardo
Published: July 2020

This study shows a set of analysis of measurements from ground-based and satellite instruments to characterize the twilight zone (TLZ) between clouds and aerosols in São Paulo, Brazil. In the vicinity of clouds turbulence measurements showed an intense upward movement of aerosol layers, while sunphotometer results showed an increase in aerosol optical depth, and lidar measurements showed an increase in the backscatter vertical profile signal.
Oceanic Lidar: Theory and Experiment
Authors: Liu Dong , Zhou Yudi , Liu Qun , Chen Weibiao , Malinka Aleksey , Han Bing , Mao Zhihua , Xu Peituo , Liu Zhipeng , Cui Xiaoyu , Wang Xiaobin , Che Haochi , Chen Peng , Song Qingjun , Zhu Xiaolei , Le Chengfeng , Liu Chong
Published: July 2020

Study on the upper ocean is of great significance to the global climate change and carbon cycle. Lidar can be used to effectively detect depth-resolved optical properties of the ocean. However, both theory and experiment of oceanic lidar are limited by complex multiple scattering. Several progresses by Zhejiang University will be illustrated in this paper: 1) a polarized lidar system was developed, and a Monte Carlo model and a radiative transfer model were established (Zhou, et al. remote sensing, 2019; Zhou, et al. Journal of remote sensing, 2019; Xu, et al. and Liu, et al. Journal of remote sensing, 2019); 2) Cross validations are demonstrated to verify the availability of the lidar system and models (Liu, et al. IEEE TGRS, 2019); 3) phase function effects on backscatter and attenuation are studied considering multiple scattering, respectively (Liu, et al. Optics Express, 2019). Oceanic lidar is proven to have great potential in marine studies.
Vehicular Motion Experiment and Data Retrieval of a Compact Floating Lidar System
Authors: Wang Qichao , Qin Shengguang , Yin Jiaping , Zhang Hongwei , Cui Tong , Wu Songhua
Published: July 2020

Accurate and rapid observation of sea surface wind is important for the research of ocean dynamic prediction model, offshore wind resource assessment, air-sea interaction and flux. A compact floating coherent Doppler lidar system named WindMast 350-M was developed by Ocean University of China (OUC) and Leice Transient Technology Co. LTD (LEICE) for the observations of sea surface wind profiles. As an observation device installed on buoy platforms, the first vehicular motion experiment was conducted at Laoshan campus of Ocean University of China(120.49°E , 36.16°N) on 06 and 12 March, 2019. During the first experiment, the wind profiles measured by the WindMast 350-M were compared with the results from a well calibrated Ground-based Coherent Doppler lidar WindMast WP350. In this contribution, the systematic design and the specifications of 350-M are presented in detail. The preliminary results of the vehicular motion experiment are discussed as well.
Studying Lump solutions, Rogue wave solutions and dynamical interaction for new model generating from lax pair
Authors: Elboree M. K.
Published: July 2020

In this paper, we consider the (3 + 1)-dimensional Burgers-like equation which arises in fluid mechanics, which constructed from Lax pair generating technique. The bilinear form for this model is obtained to construct the multiple-kink solutions. Lump solution, rogue wave solutions are constructed via the obtained bilinear form for this model. The physical phenomena for these solution are analyzed by studying the influence of the parameters for these solutions. The phase shifts, propagation directions and amplitudes for these solutions are controlled via these parameters. The collisions between the lump wave and the stripe soliton, which is called lumpoff solution are completely non-elastic interaction. Finally, the figures of the solutions are shown to study the dynamical behavior for the lump, rogue wave and the properties of the interaction phenomena under various parameters for (3 + 1)-dimensional Burgers-like equation. These results can’t be found in the previous scientific papers.
Lupus 2020
Authors: Mucke Johanna , Schneider Matthias
Published: July 2020

Was ist neu?

Klassifikation 2020 Die neuen ACR/EULAR-Klassifikationskriterien für den systemischen Lupus erythematodes (SLE) stellen einen wichtigen Beitrag zur Optimierung klinischer Studien und eine Hilfestellung zur Diagnostik dar. So kann ein SLE erst als solcher klassifiziert werden, wenn antinukleäre Antikörper (ANA) ab einer Titerhöhe von 1:80 unabhängig vom Fluoreszenzmuster nachgewiesen werden. Sind ANA nachgewiesen, erhalten Lupus-spezifische Symptome und serologische Auffälligkeiten eine unterschiedliche Wichtung für die Klassifikation.

Therapie 2020 Mit der Überarbeitung der EULAR-Empfehlungen zum Management des SLE sowie der Lupusnephritis und des Antiphospholipid-Syndroms stehen nun wichtige neue Therapieprinzipien zur Verfügung. So sollte jede Lupus-Therapie ganz im Sinne eines Treat-to-Target-Ansatzes das Ziel der Remission verfolgen. Dies dient der Sicherung des Langzeitüberlebens, der Reduktion von Schaden sowie der Verbesserung von Lebensqualität. Erreicht werden diese Ziele durch konsequente Therapie auf Basis einer regelmäßigen Evaluation der Krankheitsaktivität. Alle Patienten sollen bei Abwesenheit von Kontraindikationen Antimalariamittel erhalten. Bei unzureichendem Ansprechen auf Antimalariamittel bzw. organgefährdende Manifestationen werden Steroidpulse (über wenige Tage) sowie der frühzeitige Einsatz von Immunsuppressiva (IM) und Biologika wie Belimumab und Rituximab (off-label) empfohlen.
Lebensübergänge mit Betätigung bewältigen – Occupational Transitions
Authors: Lang Rebecca
Published: July 2020

Durch lebensverändernde Ereignisse wie eine Erkrankung oder eine Frühberentung sind bedeutungsvolle Betätigungen oft nicht mehr wie gewohnt möglich. Ergotherapeuten können Klienten darin unterstützen, diese Übergangsphasen (Transitions) durch Betätigungs- oder Umweltanpassungen zufriedenstellend zu meistern.
Die Rechtsfrage: Darf ich Klienten Medikamente reichen?
Authors: Bossow Karsten
Published: July 2020

Während eines Hausbesuchs klagt eine Klientin über Schwindel und Kopfschmerzen. Sie gibt an, die Symptome immer dann zu haben, wenn sie Bluthochdruck hat. Sie bittet ihre Therapeutin, ihr die entsprechenden Medikamente aus dem Schrank zu holen und zu reichen. Ein Medikamentenplan liegt nicht vor, und weder der Arzt noch Angehörige sind erreichbar. Wie verhält sich die Therapeutin richtig?

Ethisches Dilemma von Seite 46
Simulations of ALT-like explosive magnetic devices for ramp compression of materials by magnetically imploded liners
Authors: Buyko A. M. , Ivanova G. G. , Morozova I. V.
Published: July 2020

Revised simulations of ALT-like devices are presented. The results from these simulations closely match those from experiments and demonstrate the capabilities of the devices as applied to ramp compression of metals to pressures of 20 Mbar by imploding liners driven by ∼10 MG azimuthal magnetic fields (with currents up to 55 MA). These results can be applied to the design of experiments on isentropic compression of materials.
Charge measurement of electrospun polyvinylidene fluoride fibers using a custom-made Faraday bucket
Authors: Gade Harshal , Parsa Nitin , Roberts O. Steve , Chase George G. , Reneker Darrell H.
Published: July 2020

Electrical charges on fabrics, films, and membrane materials are of scientific interest for material development and performance. In many applications, available instruments do not have sufficient sensitivity to detect variations in charge needed for scientific investigations. This paper discusses the design and construction of a custom-made Faraday bucket for measuring the charge of electrospun polyvinylidene fluoride fiber mats of sizes 3 × 3 cm2 and 4 × 4 cm2. An electrometer directly measured the change in the voltage potentials of the inner conductor of the Faraday bucket due to the insertion of fiber mat samples. The measured potentials were converted to electrical charge by modeling the Faraday bucket as a source-free resistance–capacitance circuit. The results show that the Faraday bucket was sufficiently sensitive and measured differences in the potential and charge of the fiber mats due to variations in sample size (or mass), and it detected differences in charge depending on whether the sample was taken from the center or the edges of the electrospun fiber mats.
Effects of external magnetic fields on the rheology and magnetization of dilute emulsions of ferrofluid droplets in shear flows
Authors: Cunha L. H. P. , Siqueira I. R. , Cunha F. R. , Oliveira T. F.
Published: July 2020

We present a study of the effects of external magnetic fields on the dynamics of ferrofluid droplets in suspension and its impacts on the rheology of dilute magnetic emulsions. Our analysis considers a single two-dimensional droplet of a superparamagnetic ferrofluid in an immiscible, non-magnetizable liquid. The two-phase system is confined in a channel between parallel plates and undergoes a simple shear flow under the influence of a uniform external magnetic field. We present a theoretical formulation for the stress tensor of dilute suspensions of ferrofluid droplets in which the stresslet accounts for a magnetic field-induced traction across the droplet surface. Remarkably, the stresslet is no longer symmetric in the presence of external magnetic fields. The complex configuration of the droplet leads to a misalignment between the bulk magnetization and the external magnetic field. As a result, internal torques appear in the magnetic emulsion even when both liquid phases are symmetric fluids. We also present a comprehensive investigation of the configuration and magnetization of the suspended ferrofluid droplet as a function of the intensity and direction of the external field. Then, the stresslet is used to explore how external magnetic fields affect the rheology of dilute magnetic emulsions in terms of the shear viscosity, rotational viscosity, and first normal stress difference. Our predictions show that external magnetic fields can be effectively adjusted to control the dynamics at the droplet level and the rheology of magnetic emulsions.
Third harmonic generation in Dirac semimetal Cd3As2
Authors: Ullah Kaleem , Meng Yafei , Sun Yue , Yang Yunkun , Wang Xiangjing , Wang Anran , Wang Xinran , Xiu Faxian , Shi Yi , Wang Fengqiu
Published: July 2020

Cadmium arsenide (Cd3As2), an emerging three-dimensional Dirac semimetal, has recently generated significant interest in the area of ultrafast optics and optoelectronics. However, its nonlinear susceptibility has not been experimentally studied; thus, it is not yet possible to evaluate its potential in nonlinear optics. In this work, we investigate third harmonic generation (THG) in a 100 nm thick Cd3As2 film using broadband infrared femtosecond lasers (across 1500–2350 nm). The χ3 of Cd3As2 (2.30 × 10−19 m2 V−2) is obtained by comparing the THG spectra with a glass substrate, graphene, and monolayer MoS2. We further demonstrate a simple approach to enhance the THG signal by introducing an underlying planar micro-cavity. An enhancement of about 420 times in the THG signal was recorded at ≃1560 nm. Our results indicate that Cd3As2 thin films can provide a similar platform for nonlinear optics with respect to graphene and may offer unique potential in the mid-infrared due to its broadband light–matter interaction and excellent tunability.
Impact of Sulfur on the melt dynamics of glass forming Ti75Ni25−xSx
Authors: Wilden J. , Yang F. , Holland-Moritz D. , Szabó S. , Lohstroh W. , Bochtler B. , Busch R. , Meyer A.
Published: July 2020

Substitution of Nickel by Sulfur leads to bulk metallic glass formation in eutectic Ti75Ni25. In order to understand the improved glass forming ability, a detailed analysis of the melt dynamics was performed. We measured the density, the viscosity, and the self-diffusion of Ti75Ni25−xSx (x = 0, 5, 8) melts as a function of temperature. Moreover, the viscosity was measured under reduced gravity conditions to benchmark ground-based data. The self-diffusion coefficients were probed by incoherent, quasi-elastic neutron scattering. All measurements were combined with electrostatic or electromagnetic levitation, in order to process these highly reactive Titanium-based melts. From the measured density, the packing fraction was calculated as a function of temperature. In contrast to other bulk metallic glasses, the decrease in melt dynamics comes along with the decrease in packing density.
Influence of diametral acoustic mode on cavity flow dynamics: Zonal large eddy simulation and proper orthogonal decomposition
Authors: Wang Peng , Liu Yingzheng
Published: July 2020

The influence of a diametral acoustic mode on the flow dynamics was numerically investigated for an axisymmetric cavity system with vortex-excited acoustic resonances occurring at high Reynolds numbers and low Mach numbers. The zonal large eddy simulation (ZLES) was conducted to simulate the flow-acoustic coupling fields by the first three diametral acoustic modes at their maximum resonance intensities, respectively. First, the ZLES-simulated acoustic pressure pulsations were well validated by a preliminary acoustic modal analysis and acoustic pressure measurements in the literature. Subsequently, the acoustic-driven cavity flow dynamics were comprehensively demonstrated in terms of the time-averaged flow quantities, shear layer quantities, and high-order turbulence quantities. The results demonstrated that the shear layer momentum thickness, velocity fluctuations, and Reynolds shear stresses were remarkably intensified by the strong resonances with the first and second diametral acoustic modes. Simultaneously, large-scale helical vortex tubes were formed within the cavity, yielding an intensified flow three-dimensionality. Thereafter, the dominant flow modes behind the acoustic-driven cavity flow dynamics were extracted using the data-driven proper orthogonal decomposition from the highly noisy ZLES database. It was found that the first diametral acoustic mode significantly enhanced the dominant positions of the vertical flow-oscillation mode, yielding a large-scale flapping behavior of the mainstream flow, while the second diametral acoustic mode would modulate the cavities to synchronously absorb/release the flow streaks, resulting in the alternating expansion and compression behaviors of the mainstream flow.
Evaporating droplets in shear turbulence
Authors: Weiss Philipp , Giddey Valentin , Meyer Daniel W. , Jenny Patrick
Published: July 2020

This paper investigates droplets that evaporate and cluster in shear turbulence with direct numerical simulations. The flows are statistically stationary and homogeneous, which reduces the physical complexity and simplifies the statistical analysis. The mass loadings are about 0.1, the Stokes numbers are about 1, and the Taylor-scale Reynolds numbers are about 60. The simulations show that the clusters are anisotropic and inclined toward the flow direction on large scales, but isotropic on small scales. When the mass loading increases, the clusters contain more droplets, but their size remains unchanged, and the droplets in clusters experience higher vapor mass fractions. When the Stokes number increases, the clusters contain fewer droplets and become larger, and the droplets in clusters experience lower vapor mass fractions. When the Reynolds number increases, the clusters contain more, smaller droplets and become smaller, and the inclination angles of the clusters change.
How frequency hopping suppresses pulse-echo ambiguity in bat biosonar
Authors: Ming Chen , Bates Mary E. , Simmons James A.
Published: July 2020

Significance

The wide frequency spectrum of FM bat biosonar sounds enables accurate perception of echo delay (target distance) by contributing numerous delay estimates across frequencies. However, bats require the lowest frequencies in the broadcast to be present in echoes for all higher frequencies to contribute, too. By incorporating this feature into an existing auditory model of FM biosonar, the model can reject echoes that lack the lowest frequencies in the most recent broadcast, thus suppressing echoes of an earlier broadcast that has slightly higher low-end frequencies. This biologically inspired method adopts the bat’s frequency-hopping technique to suppress pulse-echo ambiguity in wideband systems, a serious problem for man-made wideband radar and sonar systems.
Adherence to suicide reporting guidelines by news shared on a social networking platform
Authors: Sumner Steven A. , Burke Moira , Kooti Farshad
Published: July 2020

Significance

Rates of suicide in the United States have increased over recent decades. One modifiable risk factor for suicide is exposure to sensationalized media content about suicide. Health authorities have published guidelines for news media reporting on suicide; however, uptake of recommendations remains limited. We conducted a study to analyze adherence to the guidelines on news shared on Facebook and assessed how adherence affects reader engagement. Certain harmful elements were widely prevalent in news media while protective elements were limited; however, contrary to popular perception, articles which more closely adhered to safe-reporting practices were shared more often. Variability in scores exists across nations and publisher types with implications for journalists, public health organizations, social media companies, researchers, and lay readers.
Basal ganglia beta oscillations during sleep underlie Parkinsonian insomnia
Authors: Mizrahi-Kliger Aviv D. , Kaplan Alexander , Israel Zvi , Deffains Marc , Bergman Hagai
Published: July 2020

Significance

Basal ganglia (BG) beta oscillations are a hallmark of Parkinson’s disease (PD) and are specifically reported to correlate with akinesia and rigidity during wakefulness. Studying spontaneous sleep in the nonhuman primate MPTP model of PD, we report that beta oscillations persist into NREM sleep. In the setting of the sleeping brain, BG beta oscillations correlate with a reduction of slow oscillations across the cortex and BG, and scale with insomnia severity. We suggest that similarly to the way synchronous cortico-BG beta oscillations are postulated to advance the PD akinetic motor symptoms during wakefulness, they may contribute to slow oscillation destabilization and insomnia during sleep, thereby underlying two seemingly diverging symptoms of PD.
Maternal effect killing by a supergene controlling ant social organization
Authors: Avril Amaury , Purcell Jessica , Béniguel Sébastien , Chapuisat Michel
Published: July 2020

Significance

Supergenes are clusters of linked loci producing complex alternative phenotypes. In a series of experiments, we demonstrate that a supergene controlling ant social organization distorts Mendel’s laws to enhance its transmission to adult offspring. One supergene haplotype is specific to multiple-queen colonies. This haplotype kills half of the offspring from heterozygous mothers—all eggs that do not inherit the haplotype fail to hatch. Hence, the haplotype associated with multiple-queen colonies is a selfish genetic element favoring its transmission to the detriment of the alternate haplotype associated with single-queen colonies. Selfish gene drive by a large group of linked genes impacts the social organization of ant colonies, which illustrates the intricate multilevel effects of supergenes.
Structural basis for autophagy inhibition by the human Rubicon–Rab7 complex
Authors: Bhargava Hersh K. , Tabata Keisuke , Byck Jordan M. , Hamasaki Maho , Farrell Daniel P. , Anishchenko Ivan , DiMaio Frank , Im Young Jun , Yoshimori Tamotsu , Hurley James H.
Published: July 2020

Significance

Autophagy (cellular self-eating) is essential for the health and survival of eukaryotic cells. Therapeutic autophagy induction is a major goal in the field. Rubicon inhibits autophagy and is a potential target for autophagy inducers. Rubicon is localized to its site of action in the cell by binding to the small GTPase Rab7. Here, we report a high-resolution structure of a large part of Rubicon, known as the Rubicon Homology (RH) domain. We show how the RH domain binds to Rab7 and show that the Rab7-binding residues of Rubicon are essential for Rubicon localization and autophagy inhibition. This provides a roadmap to block Rubicon localization and activity in order to upregulate autophagy.
Pervasive and perplexing pies
Authors: Kostelnick Charles
Published: July 2020

Although pie charts remain a highly popular genre for visualizing data, evident partly by their continued use in corporate annual reports, designers and theorists and have long critiqued and even denigrated them. This conflicted relationship with pie charts has resulted largely from their paucity of data, labeling difficulties, and perceptual weaknesses. Like many primary data design genres, however, pie charts attained their conventional status as a result of a long evolutionary process, initiated in the later nineteenth century by experimentation, hybrid forms, and data-rich designs. After the subsequent simplification and minimizing effects of twentieth-century modernism, pie charts have begun to experience a reemergence of innovation with digital data design, which has reintroduced hybridity into pie charts, vastly enlarged their data domain, and addressed at least some of their perceived weaknesses.
Role of sports psychology and sports nutrition in return to play from musculoskeletal injuries in professional soccer: an interdisciplinary approach
Authors: Rollo I. , Carter J. M. , Close G. L. , Yangüas J. , Gomez‐Diaz A. , Medina Leal D. , Duda J. L. , Holohan D. , Erith S. J. , Podlog L.
Published: July 2020

Musculoskeletal injuries are prevalent in professional soccer and can result in lost training time or match play. It is intuitive that the “return to play” (RTP) pathway will depend, in large part, on the expertise of sports medicine practitioners (e.g. surgeons, physicians, physiotherapists) responsible for player's recovery. Consensus statements on returning athletes to sport following injury acknowledge the contributions of sport psychology and sports nutrition. However, specific consideration on how to integrate these two recognized – but often overlooked components of injury rehabilitation – into existing sport medicine approaches has yet to be examined. Using a framework of milestones directed by the medical physician and physical trainer, the evidence is summarized and suggestions provided on the integration of sports psychology and sports nutrition into an interdisciplinary RTP approach. We examine recovery from a phase approach (acute injury and functional recovery) to highlight interdisciplinary opportunities in the management of musculoskeletal soccer injuries. An interdisciplinary approach is understood to achieve outcomes that could not be achieved within the framework of a single discipline. The incorporation of sports psychology and nutrition theoretically compliment milestones used in current medically‐based RTP models. Our hope is that this article serves as a catalyst for interdisciplinary practice and research – not only in sports nutrition and sports psychology – but across all sport and exercise disciplines.
Justifying the protest camp: How Occupy movements’ ‘intimate protest’ challenged ideas about legitimate manifestation
Authors: Dekker Mischa J.T. , Duyvendak Jan Willem
Published: July 2020

The occupation of public space has become a key part of the repertoire of contention of contemporary social movements, at the heart of Occupy Wall Street, Indignados, Nuit Debout, and revolutionary movements of the Arab Spring. Despite the enormous resonance that these movements have had, they have also engendered criticism. Based on in-depth ethnographic fieldwork of two Occupy movements–Occupy Wall Street in New York and Occupy Utrecht in the Netherlands–we show how media and other outsiders accused protesters of being insufficiently politically motivated, and overly concerned with what they considered to be ‘private matters’ such as sleeping and partying. By analysing debates and negotiations between protesters and outsiders over their right to occupy public space, we show how these encampments put received ideas on what constitutes a legitimate ‘political’ act of protest to the test. We propose the notion of ‘test’ from pragmatic sociology as a useful methodological and conceptual tool for social movement studies.
A low jitter, low cost optical chopper
Authors: Udommai Parinya , Harvey Matthew , James Murray Andrew
Published: July 2020

An optical chopper is described that has comparable performance to commercially available units. The new chopper is built within the frame of a hard disk drive, and uses the existing motor and its disk for operation. The rotation speed is measured using a photo-interrupter and is adjusted with a microcontroller. Chopping frequencies from 150 Hz to 1650 Hz with phase jitter less than 0.38 degrees per revolution have been demonstrated. The hardware design and control algorithm are described, and results showing the phase jitter characteristics are presented. The performance of this new design is comparable to that of commercial optical choppers, and can be built for a fraction of their cost.
Investigating the origins of ultra-short relaxation times of silver filaments in forming-free SiO2-based conductive bridge memristors
Authors: Bousoulas Panagiotis , Sakellaropoulos Dionisis , Papakonstantinopoulos Charalampos , Kitsios Stavros , Arvanitis Chris , Bagakis Emmanouil , Tsoukalas Dimitris
Published: July 2020

The threshold switching effect is considered of outmost importance for a variety of applications ranging from the reliable operation of crossbar architectures to emulating neuromorphic properties with artificial neural networks. This property is strongly believed to be associated with the rich inherit dynamics of a metallic conductive filament (CF) formation and its respective relaxation processes. Understanding the origin of these dynamics is very important in order to control the degree of volatility and design novel electronic devices. Here, we present a synergistic numerical and experimental approach in order to deal with that issue. The distribution of relaxation time is addressed through time-resolved pulse measurements whereas the entire switching behavior is modeled through a 2D dynamical model by taking into account the destructive interference of the drift/diffusion transport mechanisms and the Soret diffusion flux due to the intense local Joule heating. The proposed mechanism interprets successfully both the threshold to bipolar switching transition as well as the self-rectifying effects in SiO2-based memories. The model incorporates the effect of electrode materials on the switching pattern and provides a different perception of the ionic transport processes, shading light into the ultra-small lifetimes of the CF and explaining the different behavior of the silver or copper active materials in a conductive bridge random access memory architecture.
Weak measurement induced asymmetric quantum cloning
Authors: Fang Bao-Long , Chen Jiaojiao , Chen Feng , Ye Liu
Published: July 2020

Asymmetric quantum cloning (QC) is important for eavesdropping due to non-cloning quantum theorem. In this paper we propose a method to produce an asymmetric QC using weak measurement. Compared with previous proposals (1999 Phys. Rev. A 60 2764, 2004 Phy.s Rev. A 69 062316), the fidelity of one copy can be improved, while the other one reduces more smoothly. Also, the average fidelity of two copies can be raised.
Influence of uncertainty in hadronic interaction models on the sensitivity estimation of Cherenkov Telescope Array
Authors: Ohishi M , Arbeletche L , de Souza V , Maier G , Bernlöhr K , Moralejo A , Bregeon J , Arrabito L , Yoshikoshi T
Published: July 2020

Very-high-energy (VHE) interaction between cosmic-ray proton and nuclei in the atmosphere is still not perfectly understood and efforts to improve interaction models used in simulations are ongoing, with feedback from various collider and air shower experiments. Imaging Atmospheric Cherenkov Telescopes (IACTs) are indirect VHE gamma-ray detectors on the ground and cosmic-ray proton is a major background to gamma-ray measurements in these systems. Rejection power of background protons determines most part of the gamma-ray sensitivity curve of IACTs. As for an IACT system in design phase, simulated proton events are used to estimate the residual background level. We investigated the influence of the uncertainty in the current hadronic interaction models on the estimated gamma-ray sensitivity of Cherenkov Telescope Array, using several interaction models available in CORSIKA.
X-ray K and L terms estimation in free many-electron atoms and ions
Authors: Shpatakovskaya G V
Published: July 2020

Information about x-ray terms is necessary to calculate an ionization cross section of atoms or ions by intense energy beam of other particles, also for spectroscopic research method, astrophysical applications. In the paper the simple method is offered to estimate x-ray terms of many-electron atoms and ions. It is based on the atomic number and ionization degree scaling of electron orbital energies. The Dirac–Fock data of some ions of three elements (V, Pd, U) are used to construct the required dependence. One can calculate K and L x-ray terms of ions of the same and other elements using the appropriate polynomial approximations. The inaccuracy does not exceed 8%.
Laser ablation in liquid
Authors: Petrov Yu V , Khokhlov V A , Zhakhovsky V V , Inogamov N A
Published: July 2020

Laser ablation in a liquid (LAL) is an important and perspective way to create nanoparticles (NPs) necessary for modern technologies. LAL is not fully understood. Deep understanding is necessary to optimize processes and decrease high price of the LAL NPs. Today there are two groups of studies: in one of them scientists go from analyzing of bubble dynamics (thus they proceed from the late stages), while in another one, scientists investigate early stages of ablation. In the present paper we consider the process as whole: from ablation and up to formation of a bubble and its inflation. Thus we cover extremely wide range of spatiotemporal scales. We consider a role of absorbed energy and duration of pulse (femtosecond, multi-picosecond, nanosecond). Importance of supercritical states is emphasized. Diffusive atomic and hydrodynamic mixing due to Rayleigh–Taylor instability and their mutual interdependence are described. Liquid near contact with metal is heated by dissipation in strong shock and due to small but finite heat conduction in liquid; metal absorbing laser energy is hot and thus it serves as a heater for liquid. Spatial expansion and cooling of atomically mixed liquid and metal causes condensation of metal into NPs when pressure drops below critical pressure for metal. Development of bubble takes place during the next stages of decrease of pressure below critical parameters for liquid and below ambient pressure in liquid. Thin hot layer of liquid near contact expands in volume to many orders of magnitude filling the inflating bubble.
Analyzing x-ray emission of target impurities to determine the parameters of recombining laser plasma
Authors: Filippov E D , Skobelev I Yu , Revet G , Chen S N , Fuchs J , Pikuz S A
Published: July 2020

In this work, the possibility of the implementation of impurities in the compositions of solid thick targets irradiated by intense lasers is discussed in order to solve problems of optically-thick plasma diagnostics. Calculations were conducted for relative intensities of oxygen resonance lines (H-like—3p–1s, 4p–1s, 5p–1s, 6p–1s, 7p–1s transitions) in a recombination quasi-stationary model to obtain plasma parameters. In the experiment with 0.6 ns, 40 J laser pulses focused to 600 μm focal spot at solid polyvinylidene chloride target the parameters of plasma jet stopped by solid oxidized Teflon obstacle were studied by means of spatially-resolved x-ray spectroscopy.
The propagation effects in ultrafast nonlinear electro-optical modulation in thin film on a substrate
Authors: Bilyk V R , Grishunin K A , Sherstyuk N E , Mishina E D , Ovchinnikov A V , Chefonov O V
Published: July 2020

The propagation of short optical and terahertz pulses through a noncentrosymmetric (ferroelectric) film on a centrosymmetric substrate is considered. The effect of terahertz electro-induced second harmonic generation is observed in the film. It is shown that the difference in the group velocities of THz and optical pulses leads to a non-mirror-like dependence of the transient nonlinear-optical response upon a mirror image of the film–substrate structure relative to its surface.
Radiation in non-transparent and transparent plasma: Modified Planck distribution and zero vacuum fluctuations
Authors: Trigger S A
Published: July 2020

A study of equilibrium radiation in plasma media shows that the spectral energy distribution of such radiation is different from the distribution of Planck equilibrium radiation. Using the quantum electrodynamic approach, a general relation was found for the spectral energy density of equilibrium radiation in a system of charged particles for opaque and transparent media.
Comparison of laser breakdown and laser ablation ignition thresholds of combustible gas mixtures
Authors: Anishchanka Y V , Loktionov E Y
Published: July 2020

One of the strong advantages stated for laser spark plugs is the ability to ignite fuel lean mixtures resulting in improved fuel economy and reduced NO
x
emission. However, lean mixtures demand high laser pulse energies for ignition. That could be overcome by using laser ablation rather than optical breakdown plasma to establish the combustion core. For fuel equivalence ratios ϕ ≈ 0.4–1.3, we have experimentally compared ignition thresholds for these two cases at pressures of p ≈ 1–3 bar of a butane-based combustible mixture. Our results show that laser pulse energy for fuel lean mixtures ignition can be significantly (by more than an order of magnitude) reduced using the ablator (stainless steel SS304) as compared to optical breakdown.
Possible studies of explosively driven non-ideal plasma using a proton microscope at the Facility for Antiprotons and Ion Research
Authors: Shilkin N S , Yuriev D S , Mintsev V B , Bogdanov A V , Kolesnikov D S , Skoblyakov A V , Kantsyrev A V , Golubev A A , Hoffmann D H H , Varentsov D V
Published: July 2020

The article describes possible experiments with explosively driven non-ideal plasma at the proton microscope at the Facility for Antiprotons and Ion Research. It is proposed to employ linear explosive tubes for plasma generation and to measure an areal density in shock-compressed plasma of argon and xenon. The proposed experiments will provide valuable information on influence of strong interparticle interactions on thermodynamic properties of strongly coupled plasma. The density measurement will help the researchers to understand the nature of wall and wire precursors arising in the shock tubes.
Explosive character of instability development for the free surface of a conducting liquid in an electric field
Authors: Zubarev N M , Zubareva O V
Published: July 2020

In this work, a perfectly conducting liquid with a free surface, placed in an external uniform electric field, is considered. For a symmetric spatially localized perturbation of the surface, which is directed upwards, it is proved that the part of the potential energy functional which is responsible for nonlinear wave interactions is negatively defined. It is important that this result is obtained without any restrictions on the amplitude of the boundary perturbations, i.e., it takes into account high-order nonlinearities. A general conclusion is that the nonlinearity plays a destabilizing role accelerating the linear instability development of the boundary and defining its explosive character.
Optimization of the radiotransparent constructions in a mode of extreme heat loads
Authors: Bocharov A N , Pahomov E P , Petrovskiy V P , Politiko A A , Semenenko V N , Chistyaev V A
Published: July 2020

An experimental method has been developed for optimizing the composition of multilayer radiotransparent structures operating under extreme thermal loads. To optimize the composition of the layers of the radiotransparent radome researchers for the following materials with structures of the glass filler are carried out: glass-fiber laminate (GFR-CM), reinforced quartz material of SiO2–SiO2 class (HTRC-CM), organosilicon rubber with a ground mica filler (TCT). The parameters of the heat loads that cause physicochemical transformations in radiotransparent materials and significantly affect the transmission and reflection coefficients of materials, as well as their complex permittivity, are determined. It is shown that the decrease in the transmission coefficient for the construction made of HTRC-CM material is up to 3–4 dB in the frequency range from 2 to 40 GHz, and for constructions made of GFR-CM+TCT is up to 25 dB, respectively. As a result, the radome made of ceramic matrix composite HTRC-CM has the best radiotransparency characteristics.
Two-stage pyrolytic conversion of raw and pretreated bagasse into synthesis gas
Authors: Faleeva Yu M , Krysanova K O , Krylova A Yu , Zaichenko V M
Published: July 2020

Sugarcane bagasse is an abundant waste formed after extraction of sugarcane juice in the sugar-manufacturing process. This large-tonnage waste creates an ecological problem in countries—sugar producers. The study considers bagasse gasification, which is a two-stage pyrolytic conversion into synthesis gas. Raw bagasse and bagasse biocoal obtained by torrefaction and hydrothermal carbonization were used as initial materials. Experimental data are discussed including composition and quantity of gaseous products formed in the process. The results indicated that the process allows obtaining 1.26 m3 of synthesis gas from 1 kg of raw material. Its higher calorific value is 11 MJ/m3.
Research of technologies of local fuel and energy resources using for distributed power generation
Authors: Larina O M , Sytchev G A , Zaichenko V M
Published: July 2020

Development of methods of energy self-sufficiency is a priority for present power generation sector advancing. For our country, it is of particular importance. Approximately 70% of the territory of the Russian Federation (with a population of about 20 million people) are located outside centralized energy supply systems. Capacity of existing centralized energy systems is not enough for many regions of the country. At the same time, in the existing economic conditions, distributed power generation turns out to be more advantageous from an economic point of view in relation to centralized power generation. The production of energy without imported organic fuels implies local fuel and energy resources using, such as peat, wood, agricultural, household and other types of waste. Energy utilization of various types of waste, which are also local fuel and energy resources, will reduce the negative impact on the natural balance of accumulated environmental damage.
Treatment of granulated organic manure based on bird droppings by hydrothermal carbonization and torrefaction methods
Authors: Krysanova K O , Faleeva Yu M , Krylova A Yu , Zaichenko V M
Published: July 2020

Hydrothermal carbonization (HTC) and torrefaction are modern low-temperature methods of converting different types of biomass into biocoil. In both processes temperature significantly affects the product distribution and character of solid product. The heating values of HTC biocoil was much higher than torrefacted biochar and 40% higher compared to the initial raw materials (15.68 MJ/kg for raw materials, 22.3 MJ/kg for HTC 210 °C). Biomass has increased carbon content. The maximun one has biochar obtained at 210 °C (55% higher compared to the initial raw materials). The energy densification ratio and energy yield was also higher in HTC process compared to torrefaction process. Hydrochar has less ash that biochar obtained by torrefaction due to washing part of inorganic into the liquid phase.
Interaction of metastable shock waves with perturbations
Authors: Konyukhov A V , Levashov P R , Likhachev A P
Published: July 2020

The shock wave metastable behavior in equilibrium media is detected in numerical experiments. This phenomenon is directly related to the ambiguous representation of a shock wave discontinuity when the shock belongs to the S-shaped fragment of the pressure-velocity Hugoniot. After interaction with weak perturbations the metastable shock wave recovers its original form and parameters (like stable shock). If the amplitude of the perturbations exceeds some critical value, the shock wave instability is developed. The instability is accompanied by formation of the transverse secondary waves switching local post-shock parameters between two Hugoniot segments separated from each other by the absolute instability region. The problem of the metastable shock wave interaction with local entropy perturbation passing through the shock front is studied in the framework of three-dimensional problem formulation. The shock wave transition to the limiting self-oscillating mode is described. Some features of this mode are completely determined by the shape of the Hugoniot and isentropes and does not depend on the shock wave structure. Namely, the shape of the shock front corrugations and flow structure evolution are analyzed. These features may be served as marker of the corresponding thermodynamic anomalies.
Vernier laser diagnostic system for velocity measurements at Angara-5-1 facility
Authors: Pirog V A , Tishchenko I Yu , Gubskiy K L , Kuznetsov A P , Laukhin Ya N , Frolov I N , Branitskii A V
Published: July 2020

The report presents a laser diagnostic system designed to analyze the behavior of a matter in extreme states and the propagation of shock waves. The research system consists of a pair of velocity interferometer systems for any reflector (VISAR), push pull and conventional VISARs, forming a vernier scheme. This configuration was designed for Angara-5-1 facility. Test experiments of metal plate acceleration using magnetic field were carried out. The velocities up to 6 km/s were obtained.
The role of instability mechanisms in gas flame acceleration
Authors: Elyanov A E , Golub V V , Mikushkin A Yu , Petukhov V A , Volodin V V
Published: July 2020

To study the role of individual mechanisms of the flame-front instability, a series of experiments was carried out on the propagation of a spherical flame. Transparent latex shells were filled with pre-prepared hydrogen–air mixture. In various series of experiments, the percentage of hydrogen was varied. The ignition of the flame was produced by a spark discharge with an energy of 1 mJ, a discharger located in the center of the shell. Experimentally, the scattering parameters of the spherical hydrogen–air flame acceleration was found with a constant mixture composition and combustion initiation energy. It was found that at the initial stage of propagation, both acceleration and deceleration of flame front occurs. The parameters of the flame front propagation experimentally obtained are supplemented by calculations carried out using analytical models.
Analysis of the effect of boron-containing compounds and combustion catalysts on paraffin combustion rate in an oxidizer flow
Authors: Shiplyuk A N , Lukashevich S V , Simagina V I , Netskina O V , Komova O V
Published: July 2020

The paper addresses to the experimental investigations of the combustion of test samples of solid fuels based on paraffin and boron-containing compounds and combustion catalysts in the gaseous oxygen subsonic flow. Tests were carried out at the atmospheric pressure and oxygen flow velocity from 27 to 31 m/s. The mass combustion rate of the samples increased by 28% when ammonia borane was added to paraffin, and by 16% when sodium borohydride with a bit of solid oxidizer was added. The biggest amplification of the mass combustion rate using the catalyst reached 5%.
Raman spectroscopy for studying the synthesis of conducting BC3 hetero-diamonds in diamond anvil cell under high temperature
Authors: Bykov A A , Zinin P V , Bulatov K M , Filonenko V P , Kutuza I B
Published: July 2020

A direct transformation of the sintered BC3 phase to a novel diamond-like d-BC3 phase was observed in a diamond anvil cell (DAC) at high temperature, 2500 K and high pressure, 22 GPa. For heating a specimen in a DAC a laser heating (LH) system combined with an acousto-optical filter and synchronized with a video camera was used. Combining the LH system with the acousto-optical filter allows measurement of the temperature distribution under infrared (1064 nm) LH of a specimen under high pressure in a DAC. The starting material with a composition BC3 was obtained by sintering a powder of nanodiamonds with a powder of boron microparticles at 6.0 GPa during 150 s heating at 1200 °C. The quenched BC3 specimen was studied by the Raman spectroscopy.