bluuebunny/crossref_metadata_2025 huggingface dataset:
The hygrothermal performance of concrete with coarse aggregates made of recycled concrete pavements
Authors: Kočí Václav , Doleželová Magdaléna , Fiala Lukáš , Tracz Tomasz
Published: October 2020

This paper deals with an investigation of the hygrothermal performance of concretes containing various amounts of recycled aggregates originating from crushed concrete pavements. The performance, which was obtained using computational modelling of coupled heat and moisture transport, is predicted on stand-alone samples as well as on built in samples in a real construction exposed to weather data of Ostrava, Czech Republic. The results revealed that the influence of recycled aggregates as substitution for natural stone does not negatively affect the hygrothermal performance of the concrete. The highest difference found was less than 1°C and 12% of RH in the case of stand-alone samples and only 2.2% of RH when built in. Therefore, the application of crushed concrete pavements as aggregates in concrete composition can be highly recommended as it brings other benefits such as economical and environmental.
Microstructure of autonomous self-healing concrete
Authors: Stryszewska Teresa , Dudek Marta
Published: October 2020

Over the past years, many research projects in the field of construction have been based on the concept of intelligent materials. One example of such materials is self-healing concrete. This material has the ability to repair the damage that occurs, which in concrete materials means filling/closing the cracks formed. This paper describes autonomous concrete that heals itself thanks to modifications with mineral additives. The study used the basic method of evaluating the effectiveness of the healing process, which is visual observation of the material. For this purpose, tests were performed using optical, digital and electron microscopes. In addition to the observations, a chemical analysis of the composition was performed using the EDS detector mounted on the SEM. The findings indicate the ability of filling cracks with accumulating products of reaction with water.
Influence of fly ash on the pore structure of mortar using a differential scanning calorimetry analysis
Authors: Rusin Zbigniew , Stępień Piotr , Skowera Karol
Published: October 2020

In the paper a low-temperature thermoporometry using differential scanning calorimetry (DSC) was employed for analyse of influence of siliceous fly ash (FA) on pore structure of non-air-entrained mortars (pore size, connectivity). A method of interpreting a heat flux differential scanning calorimetry records in pore structure was used for this purpose. The results demonstrated that the: (i) fly ash mortars have virtually no pores inaccessible to water, unlike the mortars with plain Portland cement in which inaccessible pores constitute a significant fraction, growing with the increase in w/b; (ii) with a decrease in w/b the ink-bottle volume decreases. Fraction of this pore type is relatively larger in fly ash mortars; (iii) Siliceous fly ash increased the volume of pores greater than 8 nm, in particular in the group with radii larger than 20 nm at all w/b ratios.
Lightweight cementitious composites containing cenospheres and polypropylene fibres after exposure to high temperatures
Authors: Szymkuć Wojciech , Tokłowicz Piotr
Published: October 2020

The paper presents the results of experimental investigation of lightweight cementitious composites with cenospheres (LCCC) exposed to high temperatures. We showed the positive effect of cenospheres on post- fire residual compressive strength in previous papers. This paper focuses on the LCCC with the addition of polypropylene (PP) fibres. Specimens are heated up to 400, 600, 800, 1000 and 1200 °C. Then they are cooled to ambient temperature and their residual flexural and compressive strength is tested. The results are compared with non-heated specimens with compressive strength above 50 MPa. For plain LCCC composites, the results show significant improvement of residual compressive strength in comparison with typical concretes. No significant changes of compressive strength are found after exposure to temperatures up to 600°C – more than 85 % of the residual compressive strength is retained after exposure to this temperature for both mixes. Polypropylene fibres are found to be a successful mean to mitigate spalling without significantly lowering neither ambient nor residual compressive strength. Moreover, designed composite has low density and low thermal conductivity at room temperature.
The influence of moisture on the energy performance of retrofitted walls
Authors: Amorim Mafalda , Freitas Vasco Peixoto de , Torres Isabel , Kisilewicz Tomasz , Berardi Umberto
Published: October 2020

The renovation of old building facades should be performed mainly considering the building energy demand reduction. For this purpose, it is necessary to select retrofitted solutions that should be able of minimizing heat losses through walls. However, it is not only the nominal thermal transmittance that influences the amount of heat transported through the wall, but also the moisture content within the walls under in- service conditions. The main objective of this paper is the evaluation of the influence of the moisture content on the energy performance of retrofitted walls. A numerical study using the software WUFI Pro was carried out to quantify the influence of wind driven rain on the thermal transmittance of different wall assemblies exposed to different climates and orientations. This study reports the transient thermal transmittance of different retrofitted wall solutions as a function of moisture content.
The prognostic modelling of piezometric levels based on seepage monitoring in earthen dams
Authors: Demianiuk Alla , Stefanyshyn Dmytro
Published: October 2020

This paper presents an innovative approach to the prognostic modelling of piezometric levels in earthen dams equipped with automated monitoring systems. The main idea of the approach and the expected prognostic results are illustrated with the example of prediction of piezometric levels in the earthen dam of the Kyiv hydropower plant. This usually complex prediction task is simplified in this approach by means of simple regression models and combined situational and inductive modelling which enables overcoming the excessive uncertainty in time series. To calibrate the interpretation and prognostic models, daily monitoring data of the piezometric levels over a period of eight years was used. To verify the prediction results, monitoring data collected in the three years following this eight-year period was used. The goodness of fit of interpretation models was performed by R2 testing. To assess the goodness of the prediction fit, mean absolute and relative error estimators, as well as the Nash-Sutcliffe efficiency coefficient, were employed.
State of the art of soft robotic applications based on magneto-rheological materials
Authors: Gutenko Denys
Published: October 2020

Soft robotics is a new and exciting field of robotics which heavily relies on compliant materials. Soft robots attempt to copy the motion of living organisms and their adaptation mechanisms to the environment. New efforts in this field have paved way for the use of specific materials, e.g. electroactive polymers and/or magnetoactive (magnetorheological) MR elastomers. In this paper the author discusses the fundamental characteristics of MR fluids and elastomers, that allow them to be used as elements/components of soft robots. The advantages of using soft robots and the scope of applications for such robots are presented. The advantages and disadvantages of using MR fluids and elastomers in such soft robots are also considered. The history of the development of the idea of using MR fluids and elastomers in soft robots is presented, too. Possible applications for soft robots based on MR fluids and elastomers are considered. Various solutions for constructing a robotic gripper using MR fluids and elastomers are presented. Based on the above solutions, an analysis is made of the development of such technologies and the main problems are identified that will be the goal of solving them in the near future.
Designing a clothing supply chain network considering pricing and demand sensitivity to discounts and advertisement
Authors: Paydar Mohammad Mahdi , Olfati Marjan , Triki Chefi
Published: October 2020

These days, clothing companies are becoming more and more developed around the world. Due to the rapid development of these companies, designing an efficient clothing supply chain network can be highly beneficial, especially with the remarkable increase in demand and uncertainties in both supply and demand. In this study, a bi-objective stochastic mixed-integer linear programming model is proposed for designing the supply chain of the clothing industry. The first objective function maximizes total profit and the second one minimizes downside risk. In the presented network, the initial demand and price are uncertain and are incorporated into the model through a set of scenarios. To solve the bi-objective model, weighted normalized goal programming is applied. Besides, a real case study for the clothing industry in Iran is proposed to validate the presented model and developed method. The obtained results showed the validity and efficiency of the current study. Also, sensitivity analyses are conducted to evaluate the effect of several important parameters, such as discount and advertisement, on the supply chain. The results indicate that considering the optimal amount for discount parameter can conceivably enhance total profit by about 20% compared to the time without this discount scheme. When the optimized parameter is taken into account for advertisement, 12% is obtained as total profit.
Update Fibromyalgiesyndrom
Authors: Häuser Winfried
Published: October 2020

In der neuen Klassifikation der Krankheiten (ICD-11) der Weltgesundheitsorganisation wurde das FMS – ohne Absprache mit rheumatologischen Fachgesellschaften – aus dem Kapitel „Erkrankungen des muskuloskelettalen System und des Bindegewebes“ entfernt und in ein neu geschaffenes Kapitel „Chronischer Schmerz“ aufgenommen. Pathologische Befunde an den kleinen Nervenfasern bei einer Untergruppe von Patienten belegen nicht, dass das FMS eine Neuropathie der kleinen Nervenfasern ist. Die Überprüfung der sogenannten Tender Points zur Diagnose des FMS ist nicht mehr erforderlich. Es wurden mehrere neue diagnostische Kriterien entwickelt, welche zur symptombasierten Diagnose neben chronischen Schmerzen in mehreren Körperregionen nicht-erholsamen Schlaf und Müdigkeit (körperlich und / oder geistig) erfordern. Die nach klinischen Kriterien durchführbare Schweregradeinteilung (leicht, mittel, schwer) des FMS ist wichtig für eine abgestufte Versorgung. In Abhängigkeit von psychologischen Befunden stehen verschiedene evidenzbasierte psychotherapeutische Verfahren zur Verfügung, welche bei schweren Formen des FMS eingesetzt werden sollen. Ein komorbides (sekundäres) FMS ist bei entzündlich-rheumatischen Erkrankungen häufig und führen zu falsch hohen Aktvitätsscores. Cannabisbasierte Arzneimittel sind eine Therapieoption für eine Untergruppe von FMS-Patienten.
Healthy Aging: Gesundheit im Alter ist kein Zufall!
Authors: Gröber Uwe
Published: October 2020

Unsere Lebenserwartung ist zu ca. 30 % genetisch determiniert, die restlichen 70 % bestimmen Ernährung, körperliche Aktivität und soziale Kontakte. Wesentliche Faktoren des Alterungsprozesses sind Immunoseneszenz und Inflammaging, die mit zunehmendem Mobilitäts- und Funktionsverlust assoziiert sind. Die ausreichende Zufuhr von Mikro- und Makronährstoffen spielt bei der Modulation des Immunsystems und der Verringerung des Inflammaging eine wichtige Rolle. Neben einer erhöhten Proteinzufuhr zum Erhalt der Muskelmasse spielen im Alter v. a. die ω-3-Fettsäuren Eicosapentaensäure (EPA) und Docosahexaensäure (DHA) eine wichtige Rolle. Diese maritimen Fettsäuren wirken durch verschiedene Mechanismen antientzündlich und können so dazu beitragen, das Altern zu verlangsamen und der Entstehung von Alterskrankheiten vorzubeugen.
Timing of Repeat Cesarean Delivery for Women with a Prior Classical Incision
Authors: Ma'ayeh Marwan , Haight Paulina , Oliver Emily A. , Landon Mark B. , Rood Kara M.
Published: October 2020

Objective This study aimed to compare neonatal outcomes for delivery at 36 weeks compared with 37 weeks in women with prior classical cesarean delivery (CCD).

Study Design This was a secondary analysis of the prospective observational cohort of the Eunice Kennedy National Institute for Child and Human Development's Maternal-Fetal Medicine Unit Network Cesarean Registry. Data on cases of repeat cesarean delivery (RCD) in the setting of a prior CCD were abstracted and used for analysis. This study compared outcomes of women who delivered at 360/7 to 366/7 versus 370/7 to 376/7 weeks. The primary outcome was a composite of adverse neonatal outcomes that included neonatal intensive care unit (NICU) admission, respiratory distress syndrome (RDS), transient tachypnea of the newborn (TTN), hypoglycemia, mechanical ventilation, sepsis, length of stay ≥5 days, and neonatal death. A composite of maternal outcomes that included uterine rupture, blood transfusion, general anesthesia, cesarean hysterectomy, venous thromboembolism, maternal sepsis, intensive care unit admission, and surgical complications was also evaluated.

Results There were 436 patients included in the analysis. Women who delivered at 36 weeks (n = 176) were compared those who delivered at 37 weeks (n = 260). There were no differences in baseline characteristics. Delivery at 37 weeks was associated with a reduction in composite neonatal morbidity (24 vs. 34%, adjusted odds ratio [aOR] = 0.61 [0.31–0.94]), including a decrease in NICU admission rates (20 vs. 29%, aOR = 0.63 [0.40–0.99]), hospitalization ≥5 days (13 vs. 24%, aOR = 0.48 [0.29–0.8]), and RDS or TTN (9 vs. 19%, aOR = 0.43 [0.24–0.77]). There was no difference in adverse maternal outcomes (7 vs. 7%, aOR = 0.98 [0.46–2.09]).

Conclusion Delivery at 37 weeks for women with a history of prior CCD is associated with a decrease in adverse neonatal outcomes, compared with delivery at 36 weeks.

Key Points
Chip-scale quantum light generation enables large-scale quantum photonics opportunities
Authors: Johnson-Groh Mara
Published: October 2020

A review of chip-scale quantum light generation looks at how recent advances have helped propel the development of quantum photonics-based devices.
Introducing an extremely high output power and high temperature piezoelectric bimorph energy harvester technology based on the ferroelectric system Bi(Me)O3-PbTiO3
Authors: Chen Wei-Ting , Gurdal Ahmet Erkan , Tuncdemir Safakcan , Gambal Josh , Chen Xiao-Ming , Randall Clive A.
Published: October 2020

Here, we outline the material selection and design of a novel bimorph piezoelectric energy harvester with an extremely high energy harvesting output power density of over 8 mW/g2 cm3 up to 250 °C. With optimized mass loading, the performance can achieve five times higher output power density from 5.64 to 29.77 mW/g2 cm3, with reduced frequencies of 580–69 Hz in loading tip masses of 0.8 and 30 g, respectively. The novel harvesters were fabricated utilizing (1 − x)BiScO3-xPbTiO3 piezoceramic composition and designed to achieve the maximum figure of merit (d33 × g33), which was 15.5 × 10−12 m2/N when x = 64%. The harvester remains operational even at temperatures above 250 °C but demonstrates a systematic falloff of the high performance values with power densities of 8.7, 5.4, and 1.4 mW/g2 cm3 at 250, 300, and 350 °C, respectively. It should be noted that these performance numbers are still high compared to previous reports in the literature. The focus was then to improve the bonding/interface and dimensions that minimize clamping and depoling conditions in order to optimize the overall harvester design. We systematically outline the design considerations for room temperature and high temperature performance. Hence, we introduce a guideline for a novel bimorph harvester to provide significantly increased output power levels (mW) for higher temperature applications.
Current methodologies and approaches for the formation of core–sheath polymer fibers for biomedical applications
Authors: Mahalingam S. , Matharu R. , Homer-Vanniasinkam S. , Edirisinghe M.
Published: October 2020

The application of polymer fibers has rocketed to unimaginable heights in recent years and occupies every corner of our day-to-day life, from knitted protective textile clothes to buzzing smartphone electronics. Polymer fibers could be obtained from natural and synthetic polymers at a length scale from the nanometer to micrometer range. These fibers could be formed into different configurations such as single, core–sheath, hollow, blended, or composite according to human needs. Of these several conformations of fibers, core–sheath polymer fibers are an interesting class of materials, which shows superior physical, chemical, and biological properties. In core–sheath fiber structures, one of the components called a core is fully surrounded by the second component known as a sheath. In this format, different polymers can be applied as a sheath over a solid core of another polymer, thus resulting in a variety of modified properties while maintaining the major fiber property. After a brief introduction to core–sheath fibers, this review paper focuses on the development of the electrospinning process to manufacture core–sheath fibers followed by illustrating the current methodology and approaches to form them on a larger scale, suitable for industrial manufacturing and exploitation. Finally, the paper reviews the applications of the core–sheath fibers, in particular, recent studies of core–sheath polymer fibers in tissue engineering (nerve, vascular grafts, cardiomyocytes, bone, tendons, sutures, and wound healing), growth factors and other bioactive component release, and drug delivery. Therefore, core–sheath structures are a revolutionary development in the field of science and technology, becoming a backbone to many emerging technologies and novel opportunities.
Simulation of electrorheological plasmas with superthermal ion drift
Authors: Kana Dimitri , Dietz Christopher , Thoma Markus H.
Published: October 2020

By applying an external electric AC field to a dusty plasma, the micro-particles arrange in strings or chains caused by the wake potential between the micro-particles due to the ion drift in the plasma. In analogy to electrorheological fluids, such a system is called electrorheological plasma. In contrast, in the case of an external DC field, no string formation has been observed. Therefore, turning gradually the AC field into a DC field, a phase transition from a string-like electrorheological to an isotropic dusty plasma is expected. A molecular dynamics (MD) simulation assuming a superthermal ion drift is performed for studying this phase transition. A superthermal ion drift in an external electric field could be realized in a future microgravity experiment with complex plasmas proposed for the ISS. In this case, the MD simulation presented here predicts a crossover transition from a string fluid to an isotropic system if the AC field is turned into a DC field. The details of the transition depend on the gas pressure, particle size, and particle density. A microscopic explanation due to particle collisions for the phase transition could be identified from the simulation.
Controllability of periodic bilinear quantum systems on infinite graphs
Authors: Ammari Kaïs , Duca Alessandro
Published: October 2020

In this work, we study the controllability of the bilinear Schrödinger equation (BSE) on infinite graphs for periodic quantum states. We consider the BSE i∂tψ = −Δψ + u(t)Bψ in the Hilbert space Lp2 composed of functions defined on an infinite graph G verifying periodic boundary conditions on the infinite edges. The Laplacian −Δ is equipped with specific boundary conditions, B is a bounded symmetric operator, and u∈L2((0,T),R) with T > 0. We present the well-posedness of the BSE in suitable subspaces of D(|Δ|3/2). In such spaces, we study the global exact controllability and we provide examples involving tadpole graphs and star graphs with infinite spokes.
Improvement in the stability of a 40Ca+ ion optical clock using the Ramsey method
Authors: Zhang Baolin , Huang Yao , Hao Yanmei , Zhang Huaqing , Zeng Mengyan , Guan Hua , Gao Kelin
Published: October 2020

The fractional uncertainty of the 40Ca+ optical clock in our laboratory has been evaluated to be 2.2×10−17, but it is difficult to evaluate the statistical uncertainty of the output frequency at this level, limited by the frequency stability associated with the quantum projection noise (QPN). A reduction in the stability is required to shorten the averaging time for a certain statistical uncertainty level. To improve the stability, the Ramsey method is introduced in the locking process. To improve the reliability and continuity, we introduce the idea of using auxiliary Rabi probes to avoid fringe slips in the Ramsey interrogation and to automatically search for resonance. The stability of a single 40Ca+ ion frequency standard is improved from 6.3×10−15/τ to 2.5×10−15/τ, where τ is the averaging time in seconds, which is close to the QPN limit for an 80-ms-long Ramsey interrogation. We obtain a stability of 1.5×10−17 at an averaging time of 21 000 s and an uptime rate of 93.8% for a 34-h-long run. These methods can easily be applied to other ion or neutral atom optical clocks.
Flattening of the tokamak current profile by a fast magnetic reconnection with implications for the solar corona
Authors: Boozer Allen H.
Published: October 2020

During tokamak disruptions, the profile of the net parallel current is observed to flatten on a time scale that is so fast that it must be due to a fast magnetic reconnection. After a fast magnetic reconnection has broken magnetic surfaces, a single magnetic field line covers an entire volume and not just a magnetic surface. The current profile, given by K≡μ0j||/B, relaxes to a constant within that volume by Alfvén waves propagating along the chaotic magnetic field lines. The time scale for this relaxation determines the commonly observed disruption phenomena of a current spike and a sudden drop in the plasma internal inductance. An efficient method for studying this relaxation is derived, which allows a better understanding of the information encoded in the current spike and the associated sudden drop in the plasma internal inductance. Implications for coronal heating are also discussed.
A cryogenic setup for multifunctional characterization of luminescence and scintillation properties of single crystals
Authors: Pandey Indra Raj , Cheon Jongkyu , Daniel D. Joseph , Kim MinJeong , Kim Yeongduk , Lee Moo Hyun , Kim Hongjoo
Published: October 2020

This article reports on a cryogenic setup that can be used for multifunctional experimental purposes. The temperature of the setup can be set from 10 K to 300 K. Different kinds of experiments were carried out in this experimental setup such as (1) luminescence emission, light yield, and decay time measurement under excitation of 266 nm laser and 280 nm LED sources, (2) thermoluminescence (TL) measurement under an x-ray excitation source, (3) scintillation property measurements such as light output, energy resolution, and decay time under 137Cs (662 keV γ-rays) and 241Am (5.4 MeV α) isotope sources, and (4) scintillation measurement under a 90Sr beta source through the continuous single-photon counting technique. The luminescence and scintillation properties of various molybdate and tungstate crystals such as CaMoO4, Na2Mo2O7, Pb2MoO5, CdWO4, and ZnWO4 are characterized and reported in the present work. The TL measurement of a CaMoO4 crystal is carried out from 10 K to 300 K, and various kinetic parameters such as order of kinetics, frequency factor, activation energy, and figure of merit are calculated for different TL peaks. As the temperature goes down from room to 10 K, the light yield of all studied crystals increases. Since the light yield of the crystal increases as temperature decreases toward 10 K, this experimental setup can be used for the characterization of luminescence and scintillation properties of a single crystal for rare event searches such as neutrinoless double-beta decay and dark matter.
Numerical simulation of the collision behaviors of binary unequal-sized droplets at high Weber number
Authors: Cong Hongchuan , Qian Lijuan , Wang Yiting , Lin Jianzhong
Published: October 2020

In the spray combustion process, the distribution of droplet size and velocity will affect the atomization performance of the fuel and the combustion effect. Compared with binary equal-sized droplet collisions, binary unequal-sized droplet collisions are more in line with the actual situation. In this paper, a numerical investigation of binary unequal-sized droplet collision has been performed under different high Weber numbers (from 210 to 810) and impact parameters (B ≈ 0.3–0.9) by a coupled level-set and volume of fluid method with adaptive mesh refinement technology. Unlike the coalescence and separation phenomena at low and medium Weber numbers, at high Weber numbers, due to the difference in velocity between large and small droplets, the rim expands radially outward in different ways and further breaks up. The splashing behavior of the droplets can also be observed. As the Weber number increases, the breakup moment of the droplets advances and the maximum radial deformation diameter increases first (We = 210–360) and then decreases (We = 360–810). By changing the impact parameters, it can be found that binary off-center collisions are associated with rotational motion. At larger impact parameters, the features of the capillary wave instability can be observed on the surface of the ligament.
Effects of microvortex generators on cavitation erosion by changing periodic shedding into new structures
Authors: Qiu Ning , Zhou Wenjie , Che Bangxiang , Wu Dazhuan , Wang Leqin , Zhu Han
Published: October 2020

Cavitation erosion is a common phenomenon and continues to be a primary concern in the fields of hydraulic machinery. It is important to develop effective methods to avoid adverse effects. In the previous studies, the microvortex generators (VGs) were arranged parallel to the leading edge on the surface of the NACA0015 hydrofoil and, thus, changed the feature of the attached cavity. However, the effect on cavitation erosion has not been studied. The current work aims at understanding the aggressiveness of cavitation structures and the intensity of impact changed by microvortex generators. This study presents findings of experimental investigation of impulsive loading on the hydrofoil surface from collapsing cavities. Attempts to predict the cavitation erosion aggressiveness and the relationship with cavitation structures were based on visual observations. Under certain cavitation conditions, the periodic shedding disappears after the micro-VGs are installed. By dispersing the collapse in time and space, the maximum pressure fluctuation is reduced by 32% and the acoustic power is reduced by 10.8 dB at about 20 kHz. The maximum impact energy appears to be concentrated around the cavity closure. The maximum impact energy of a hydrofoil with VGs is 48% of that of a smooth hydrofoil. When the attack angle is lower, the erosion at the leading edge is more obvious on the smooth hydrofoil. Thus, the effect of VGs on alleviating the erosion at the leading edge is more prominent. The characteristic feature of vortex generators is their strong swirling motion that allows them to promote large-scale mixing of fluids with different momentum and energy. The unsteadiness is alleviated by VGs because of the interaction with the reverse flow.
Ab initio structure and thermodynamics of the RPBE-D3 water/vapor interface by neural-network molecular dynamics
Authors: Wohlfahrt Oliver , Dellago Christoph , Sega Marcello
Published: October 2020

Aided by a neural network representation of the density functional theory potential energy landscape of water in the Revised Perdew–Burke–Ernzerhof approximation corrected for dispersion, we calculate several structural and thermodynamic properties of its liquid/vapor interface. The neural network speed allows us to bridge the size and time scale gaps required to sample the properties of water along its liquid/vapor coexistence line with unprecedented precision.
Decomposition pathway of C4F7N gas considering the participation of ions
Authors: Chen Li , Zhang Boya , Li Xingwen , Yang Tao
Published: October 2020

Recently, fluoronitrile C4F7N is regarded as a promising alternative gas for SF6, and its global warming potential (GWP) is extremely high. C4F7N has good insulation properties and a relatively low GWP, so it can be used as an insulation medium for gas-insulated switchgears. Some studies have been conducted on the decomposition pathway of C4F7N gas that may produce possible neutral molecules and free radicals, which helps understand the thermal decomposition of C4F7N. However, anions and cations will be produced under discharge conditions. In these cases, the decomposition pathway of C4F7N will be different. In this paper, the ionization decomposition pathway and the attachment decomposition pathway of C4F7N were first calculated, while the recombination processes of the cations and anions were also considered. The results can reveal the decomposition mechanism of C4F7N and the recombination mechanism of the stable products under discharge conditions. The energy changes of all the reactions were calculated, which reveals the difficulty of chemical reactions. To better investigate the formation mechanism of stable products, the partial discharge experiment was also carried out, and the decomposition products of C4F7N mixed gas were detected. Finally, the ionization energy and electron affinity energy of the stable products were also calculated, which can determine the difference in the total electronic energy between the neutral molecule and the ion. The results provide an important reference for studying the decomposition characteristics of C4F7N gas under discharge conditions from the theoretical aspect.
Droplet breakup and rebound during impact on small cylindrical superhydrophobic targets
Authors: Ding Siyu , Liu Xin , Wu Xiaomin , Zhang Xuan
Published: October 2020

The impact behavior of a water droplet on small cylindrical superhydrophobic targets is studied numerically and theoretically. A numerical model using the volume of fluid method is developed to simulate the droplet impact process on small cylindrical superhydrophobic targets. The model is verified by comparing the calculated results with the experimental observations in our previous work and reference. The influences of the Weber number and the target-to-droplet diameter ratio (less than one) on the droplet impact behaviors, including the droplet profile and the deformation factor, are investigated. The results indicate that a larger Weber number accelerates the spreading and falling of the droplet and promotes the droplet breakup. An increase in the diameter ratio delays the spreading and falling of the droplet on the side of the target, thus enhancing the deformation and rebound of the droplet. Both the increases in the Weber number and the diameter ratio contribute to a larger maximum deformation factor. Furthermore, the droplet breakup criterion is analyzed theoretically based on the energy conservation. A formula describing the relationship between the critical Weber number and the diameter ratio for the droplet breakup is proposed, which shows high prediction accuracy compared with the numerical values. The critical Weber number for the droplet breakup becomes larger with the increase in the diameter ratio. The findings in this research deepen our understanding of the mechanism of droplet impact on small targets.
A tunable plasmonic resonator using kinetic 2D inductance and patch capacitance
Authors: Muravev V. M. , Semenov N. D. , Andreev I. V. , Gusikhin P. A. , Kukushkin I. V.
Published: October 2020

We have studied the microwave response of a high-mobility two-dimensional electron system (2DES) contacted by two side electrodes. Using kinetic inductance of the 2DES and inter-electrode capacitance, we have constructed a subwavelength 2D plasmonic resonator. We have shown that the resonant frequency of this circuit can be controlled by 2D electron density, external magnetic field, or size of the electrodes. This opens up possibilities for using arrays of plasmonic circuits as tunable components in different frequency ranges.
A highly efficient nanofocusing system for soft x rays
Authors: Takeo Yoko , Motoyama Hiroto , Shimamura Takenori , Kimura Takashi , Kume Takehiro , Matsuzawa Yusuke , Saito Takahiro , Imamura Yoichi , Miyashita Hiroaki , Hiraguri Kentaro , Hashizume Hirokazu , Senba Yasunori , Kishimoto Hikaru , Ohashi Haruhiko , Mimura Hidekazu
Published: October 2020

The focusing of x rays is essential in various types of x-ray microscopy because the size and flux of the illuminating beam determine the spatial resolution and signal intensity, respectively. A system with grazing incidence mirrors allows highly efficient x ray focusing with beam dimensions on the nanometer scale. Tube-shaped mirrors with a large numerical aperture and high demagnification, including ellipsoidal mirrors and Wolter mirrors, have recently been developed for soft x-ray nanofocusing. However, these mirrors have low efficiency because they cannot focus the central part of the illumination beam. Here, we propose a two-stage focusing system, in which a ring-shaped beam formed by a ring-focusing mirror illuminates a quasi-Wolter mirror. A prototype of the system is experimentally constructed at beamline BL25SU-A of SPring-8. Observation of the wavefront error based on ptychography enables efficient alignment of the two mirrors. Using this alignment procedure, we achieve a spot size of less than 200 nm at 300 eV.
Effective linewidth shifts in single-molecule detection using optical whispering gallery modes
Authors: Subramanian Sivaraman , Vincent Serge , Vollmer Frank
Published: October 2020

Here, we report shifts of the linewidth of a plasmon enhanced whispering gallery mode (WGM) of a glass microsphere cavity due to binding of single sub-kDa molecules. The observed linewidth of the WGM can either increase or decrease upon binding of single molecules depending on the location of their binding sites. The linewidth shifts arise due to the change in the unresolved frequency splitting of standing wave modes (SWMs). These SWMs are formed due to the scattering from the gold nanoparticles attached to the WGM. Monitoring the WGM linewidth provides a robust method for sensing single molecules over prolonged time periods as the linewidth is unaffected by changes in the host refractive index due to drifts in temperature, pressure, or change in the concentration of buffers.
Does verb transitivity influence word association responses?
Authors: Thwaites Peter
Published: October 2020

Although several studies have investigated the influence of the grammatical class of cue words on response patterns in the
word association task, relatively little is known about the influence of more fine-grained distinctions such as cue transitivity. The present study tests two predictions, made in existing studies, of the influence of this variable. The first is that cue
transitivity would influence the grammatical class of responses; the second, that it would affect the directionality of position-based, or
syntagmatic, responses. English language associative responses to 49 transitive and 49 intransitive cues were gathered from 53 English L1
respondents. These responses were then analysed according to their grammatical class and categorical designation. Results suggested that cue
transitivity influences both of these measurements: transitive cues yielded more noun responses and more associations classified as likely
to follow the cue in text than did intransitives, while transitives received more verb responses and more associations likely to precede the
cue. These results are discussed in the light of contiguity-based and semantic theories of the determinants of word association.
The structure of covtree: searching for manifestly covariant causal set dynamics
Authors: Zalel Stav
Published: October 2020

Covtree—a partial order on certain sets of finite, unlabeled causal sets—is a manifestly covariant framework for causal set dynamics. Here, as a first step in picking out a class of physically well-motivated covtree dynamics, we study the structure of covtree and the relationship between its paths and their corresponding infinite unlabeled causal sets. We identify the paths which correspond to posts and breaks, prove that covtree has a self-similar structure, and write down a transformation between covtree dynamics akin to the cosmic renormalisation of Rideout and Sorkin’s classical sequential growth models. We identify the paths which correspond to causal sets which have a unique natural labeling, thereby solving for the class of dynamics which give rise to these causal sets with unit probability.
Comment on ‘Defining the electromagnetic potentials’
Authors: van Hees Hendrik
Published: October 2020

In this comment it is shown that the argument for a unique determination of the electromagnetic potentials in classical electrodynamics by Davis (2020 Eur. J. Phys.
41 045202) is flawed. To the contrary the ‘gauge freedom’ of the electromagnetic potentials has proven to be one of the most important properties in the development of modern physics, where local gauge invariance with its extension to non-abelian gauge groups is a key feature in the formulation of the standard model of elementary particles in terms of a relativistic quantum field theory.
Sensitive detection of metastable NO and N2 by reactive collisions with laser-excited Li
Authors: Guan Jiwen , Sixt Tobias , Dulitz Katrin , Stienkemeier Frank
Published: October 2020

In a proof-of-principle experiment, we demonstrate that metastable nitric oxide molecules, NO(a4Π
i
), generated inside a pulsed, supersonic beam, can be detected by reactive gas-phase collisions with electronically excited Li atoms in the 22P3/2 state. Since the internal energy of NO(a4Π
i
, v ⩽ 4) is lower than the ionization potential of Li in the 22S1/2 electronic ground state, we observe that the product ion yield arising from autoionizing NO(a4Π
i
) + Li(22S1/2) collisions is a factor of 21 lower than the ion yield from NO(a4Π
i
) + Li(22P3/2) collisions. We also compare our findings with measurements of relative rates for metastable N2 + Li(22S1/2) and metastable N2 + Li(22P3/2) reactive collisions. Using this detection method, we infer densities of ≈600 NO(a4Π
i
) molecules/cm3 and ≈6 ⋅ 104 metastable N2 molecules/cm3 in the interaction region. Our results also allow for an estimate of the fractional population of NO(a4Π
i
, v ⩾ 5) prior to the collision process. The production of NO(a4Π
i
) in selected vibrational states using laser excitation from the X2Π
r
ground state will open possibilities for the detailed study of vibrational-state-selected NO(a4Π
i
)–Li(22P3/2) collisions.
Evading thermal population influence on enantiomeric-specific state transfer based on a cyclic three-level system via ro-vibrational transitions
Authors: Zhang Quansheng , Chen Yu-Yuan , Ye Chong , Li Yong
Published: October 2020

Optical methods of enantiomeric-specific state transfer had been proposed theoretically based on a cyclic three-level system of chiral molecules. According to these theoretical methods, recently the breakthrough progress has been reported in experiments (Eibenberger et al 2017 Phys. Rev. Lett.
118 123002; Pérez et al 2017 Angew. Chem. Int. Ed.
56 12512) for cold gaseous chiral molecules but with achieving low state-specific enantiomeric enrichment. One of the limiting factors is the influence of the thermal population in the selected cyclic three-level system based on purely rotational transitions in the experiments. Here, we theoretically explore the improvement of the enantiomeric-specific state transfer at finite temperature by introducing ro-vibrational transitions for the cyclic three-level system of chiral molecules. Then, at the typical experimental temperature, approximately only the lowest state in the desired cyclic three-level system is thermally occupied and the optical method of enantiomeric-specific state transfer works well. Comparing with the case of purely rotational transitions where all the three states are thermally occupied, this modification will remarkably increase the obtained state-specific enantiomeric enrichment with enantiomeric excess being approximately 100%.
Understanding the intrinsic compression in polycrystalline films through a mean-field atomistic model
Authors: Vasco Enrique , Ramírez-Peral María J , Michel Enrique G , Polop Celia
Published: October 2020

Mullins’ theory predicts the buildup of adatoms during surface diffusion at the edges of grooves where grain boundaries emerge to the surface of a polycrystalline film. However, the mesoscopic nature of this theory prevents the identification of the atomic-scale physical mechanisms involved in this phenomenon. Here, we interpret the buildup of adatoms in atomistic terms through a mean-field rate-equation model and demonstrate both its kinetic nature and its impact on the intrinsic stress in these systems. Furthermore, the model provides estimates of the surface profile of intrinsic stress, of its typical mean values, and of the dependence of stress on temperature and deposition flux for different growth stages. These estimates agree well with reported experimental results obtained from recent advances in nanoscale mapping of mechanical stresses on the surface of polycrystalline films.
Disentangling complete and incomplete fusion events in 12C + 169Tm reaction by spin-distribution measurements
Authors: Sood Arshiya , Thakur Swati , Sharma Arzoo , Sharma Vijay R , Yadav Abhishek , Sharma Manoj K , Singh B P , Kumar R , Bhowmik R K , Singh Pushpendra P
Published: October 2020

The spin-distributions of different reaction products populated via x
n and α/2αx
n channels in

C

12

+

Tm

169

system have been measured at E
lab ≈ 6, 7 and 7.5 MeV A−1 to disentangle complete and incomplete fusion events. Particle (p, α)-γ-coincidences were recorded to identify evaporation residues channel-by-channel. The spin-distributions of fusion evaporation and direct-α-emitting channels are found to be distinct corroborating the involvement of entirely different reaction dynamics in their production, respectively termed as complete (CF) and incomplete fusion (ICF). The values of mean input angular momenta, obtained from the analysis of the spin-distributions, involved in ICF-α/2α
xn channels are estimated to be larger than that observed in CF-xn/α
xn channels. For ICF-α/2αxn channels, the multiplicity of fast-α particle emission increases with the magnitude of input angular momentum imparted into the system. The CF residues display a population of broad spin range while the ICF residues are confined to a narrow spin range generally localized in the higher spin states. Findings of the present work conclusively demonstrate the possibility to populate high spin states in final reaction products using ICF, which are otherwise not accessible. Further, an attempt has been made to study the variation of input angular momentum with the choice of different entrance-channel parameters. It has been observed that the value of input angular momentum involved in ICF-α/2α
xn channels increases with the deformation and entrance-channel mass-asymmetry parameter, indicating strong entrance-channel dependence of ICF dynamics.
Why thermal conductivity of CaO is lower than that of CaS: a study from the perspective of phonon splitting of optical mode
Authors: Yang Zhonghua , Yuan Kunpeng , Meng Jin , Zhang Xiaoliang , Tang Dawei , Hu Ming
Published: October 2020

Generally speaking, for materials with the same structure, the thermal conductivity is higher for lighter atomic masses. However, we found that the thermal conductivity of CaO is lower than that of CaS, despite the lighter atomic mass of O than S. To uncover the underlying physical mechanisms, the thermal conductivity of CaM (M = O, S, Se, Te) and the corresponding response to strain is investigated by performing first-principles calculations along with the phonon Boltzmann transport equation. For unstrained system, the order of thermal conductivity is CaS > CaO > CaSe > CaTe. This order remains unchanged in the strain range of −2% to 5%. When the compressive strain is larger than 2%, the thermal conductivity of CaO surpasses that of CaS and becomes the highest thermal conductivity material among the four compounds. By analyzing the mode-dependent phonon properties, the phonon lifetime is found to be dominant over other influential factors and leads to the disparate response of thermal conductivity under strain. Moreover, the changing trend of three-phonon scattering phase space is consistent with that of phonon lifetime, which is directly correlated to the phonon frequency gap induced by the LO-TO splitting. The variation of Born effective charge is found to be opposite for CaM. The Born effective charge of CaO decreases with tensile strain increasing, demonstrating stronger charge delocalization and lower ionicity, while the Born effective charges of CaS, CaSe, and CaTe show a dramatic increase. Such variation indicates that the bonding nature can be effectively tuned by external strain, thus affecting the phonon anharmonic properties and thermal conductivity. The difference of bonding nature is further confirmed by the band structure. Our results show that the bonding nature of CaM can be modulated by external strain and leads to disparate strain dependent thermal conductivity.
Analysis on reversible/irreversible electroporation region in lung adenocarcinoma cell model in vitro with electric pulses delivered by needle electrodes
Authors: Lv Yanpeng , Tang Xiao , Peng Wencheng , Cheng Xian , Chen Shuo , Yao Chenguo
Published: October 2020

Irreversible electroporation (IRE) is a minimally invasive tumor therapy using pulsed electric field with high intensity while the important tissues such as blood vessel, bile duct, and nerve are preserved. In addition to ablation area, reversible electroporation (RE) region is also generated using needle electrodes for pulse delivery. The goal of this work is to study the generation of RE region and ablation region on a 2D lung adenocarcinoma cell model in vitro. The tumor model is exposed to electric pulses with various number. The calcium AM and propidium iodide (PI) are examined to detect the ablation area and electroporation area, respectively. The results show that electroporation area firstly tends to plateau after approximately 50 pulses, while the ablation area continues to increase. The percentage of IRE area in total electroporation area increases with additional pulses, which means that RE region could be gradually turned into ablation area with increased pulse number. However, the percentage of IRE area only achieves to 54% for 200 pulses, which indicates that RE region still cannot be completely removed. RE and IRE thresholds appear to converge as the number of pulses increases. An equation between pulse number and the electric field threshold of ablation including the electric field threshold of RE is also provided for lung adenocarcinoma cell ablation. This work may have the value for the optimization of IRE protocols on tumor ablation.