bluuebunny/crossref_metadata_2025 huggingface dataset:
Pläne der Ampelkoalition: Gute Vorsätze
Authors: Kucera Martin
Published: February 2022

Die neue Bundesregierung hat sich viel vorgenommen für das Gesundheitswesen. Nichts weniger als eine bedarfsgerechte Gesundheitsversorgung, menschliche und qualitativ hochwertige Medizin und Pflege hat sich die Ampelkoalition zum Ziel gesetzt. Einen ersten Dämpfer musste Bundesgesundheitsminister Karl Lauterbach (SPD) mit der Verteilungsdebatte um den Pflegebonus aber bereits hinnehmen.
Karl Lauterbach: Krisenmanager
Authors: Orth Anne
Published: February 2022

Er muss die Pandemie in den Griff bekommen und dringend notwendige Reformen im Gesundheitssystem einleiten. Der Druck, unter dem Karl Lauterbach steht, ist enorm. Ob der neue Bundesgesundheitsminister die in ihn gesetzten Erwartungen erfüllen kann, wird sich zeigen.
Karriereplanung: Zwischen Mitarbeiter-Wünschen und Abteilungszielen
Authors: Contzen Bernd von , Nehrig Claudia
Published: February 2022

Was sich Mitarbeitende an Weiterentwicklung wünschen, ist nicht immer das, was ein Krankenhaus braucht. Diese mitunter gegensätzlichen Perspektiven zu verbinden, ist Aufgabe von Führungspersonen. Wer bereit ist, dafür Augen und Ohren offenzuhalten und Brücken zu bauen, ist auf dem richtigen Weg, wie zwei Pflege-Führungskräfte beschreiben.
Vielfalt in der OP-Logistik: Viele Wege führen zu mehr OP-Kapazität
Authors: Otten Hubert
Published: February 2022

Im Jahr 2020 wurden in Deutschland 15,82 Millionen vollstationäre Operationen durchgeführt. Hinzu kommen rund zwei Millionen ambulante Operationen. Mit sinkender Verweildauer wird die Bedeutung der Operationssäle im Leistungsprozess eines Krankenhauses weiter zunehmen.
Digitale Patientenaufklärung: Arztgespräch auf Augenhöhe mit digitaler Hilfe
Authors: Schweigerer Lothar , Ofosu Kwaku
Published: February 2022

Noch wird die Patientenaufklärung zum großen Teil in Papierform dokumentiert, mit entsprechendem bürokratischen Aufwand. Doch elektronische Alternativen werden immer beliebter. Davon profitieren auch Patientinnen und Patienten, die zum Beispiel durch Videos verständliche und individualisierte Informationen über einen bevorstehenden medizinischen Eingriff erhalten.
Führungswechsel beim DBfK: Krankenschwester, Soziologin, Geschäftsführerin
Authors: Heeser Alexandra
Published: February 2022

Anfang Oktober 2021 hat die 56-jährige Soziologin und Krankenschwester Dr. phil. Bernadette Klapper die Bundesgeschäftsführung des Deutschen Berufsverbandes für Pflegeberufe (DBfK) von Franz Wagner übernommen. Sie hat Abschlüsse der Universitäten Hamburg und Bordeaux und kann mit ihrer langjährigen Erfahrung in der stationären und ambulanten Pflege hervorragend die Interessen der Profession Pflege bündeln und vertreten.
Ocean waves could give offshore wind turbines a boost
Authors: Johnson-Groh Mara
Published: February 2022

Study of floating wind turbines in unsteady wave conditions aims to improve the efficiency and lifespan of offshore windfarms.
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2
-Harish-Chandra modules for sl2⋉L(4)
Authors: Mazorchuk Volodymyr , Mrđen Rafael
Published: February 2022

We use analogs of Enright’s and Arkhipov’s functors to determine the quiver and relations for a category of sl2⋉L(4)-modules that are locally finite (and with finite multiplicities) over sl2. We also outline serious obstacles to extend our result to sl2⋉L(k) for k > 4.
The Dirac sea for the non-separable Hilbert spaces
Authors: Bachelot Alain
Published: February 2022

We give a rigorous construction of the Dirac sea for the fermionic quantization in non-separable Hilbert spaces. These canonical anticommutation relations and representations depend on the axiom of choice, and hence, they are not unique; nevertheless, they are unitarily equivalent to the classic Fock representation.
Load estimation in unsteady flows from sparse pressure measurements: Application of transition networks to experimental data
Authors: Iacobello Giovanni , Kaiser Frieder , Rival David E.
Published: February 2022

Inspired by biological swimming and flying with distributed sensing, we propose a data-driven approach for load estimation that relies on complex networks. We exploit sparse, real-time pressure inputs, combined with pre-trained transition networks, to estimate aerodynamic loads in unsteady and highly separated flows. The transition networks contain the aerodynamic states of the system as nodes along with the underlying dynamics as links. A weighted average-based (WAB) strategy is proposed and tested on realistic experimental data on the flow around an accelerating elliptical plate at various angles of attack. Aerodynamic loads are then estimated for angles-of-attack cases not included in the training dataset so as to simulate the estimation process. An optimization process is also included to account for the system's temporal dynamics. Performance and limitations of the WAB approach are discussed, showing that transition networks can represent a versatile and effective data-driven tool for real-time signal estimation using sparse and noisy signals (such as surface pressure) in realistic flows.
Chemical reaction zone measurements in pressed trinitrotoluene (TNT) and comparison with triaminotrinitrobenzene (TATB)
Authors: Sollier Arnaud , Hébert Philippe , Letremy Roland
Published: February 2022

Photonic Doppler velocimetry and digital high-speed shadowgraphy have been used to characterize the chemical reaction zone parameters of pressed trinitrotoluene (TNT) samples with an initial density of 1.568 g cm−3. Comparison of the nanosecond time-resolved particle velocity histories of the free surfaces of detonating charges in air and light vacuum and of the interfaces between TNT detonation products and lithium fluoride or polymethyl methacrylate windows allow one to bracket the von Neumann spike pressure between 24.8 and 28.8 GPa. Our velocity waveforms confirm the two-step reaction pathway already observed in TNT, triaminotrinitrobenzene (TATB), and nitromethane, with a first fast energy release over 80 ns followed by a slower release over 250 additional ns. We consider the end of the first release zone as the locus of the Chapman–Jouguet (CJ) state, and the CJ pressure thus lies between 17.6 and 17.7 GPa. The energy release is not completed in this Jouguet plane but only after about ≈280 ns when the carbon cluster formation process ends. This corresponds to both the end of the slow release part of the interface velocity profiles and to the moment at which the free surface velocity profiles reach their maximum. Our shadowgraphy images confirm that carbon formation occurs very rapidly after the detonation breakout, in good agreement with previous time-resolved small-angle x-ray scattering measurements. The comparison with similar results previously obtained on TATB allows one to further highlight their similarities, which mainly result from their excess carbon production at late times.
Surface diffusion of a glassy discotic organic semiconductor and the surface mobility gradient of molecular glasses
Authors: Li Yuhui , Bishop Camille , Cui Kai , Schmidt J. R. , Ediger M. D. , Yu Lian
Published: February 2022

Surface diffusion has been measured in the glass of an organic semiconductor, MTDATA, using the method of surface grating decay. The decay rate was measured as a function of temperature and grating wavelength, and the results indicate that the decay mechanism is viscous flow at high temperatures and surface diffusion at low temperatures. Surface diffusion in MTDATA is enhanced by 4 orders of magnitude relative to bulk diffusion when compared at the glass transition temperature Tg. The result on MTDATA has been analyzed along with the results on other molecular glasses without extensive hydrogen bonds. In total, these systems cover a wide range of molecular geometries from rod-like to quasi-spherical to discotic and their surface diffusion coefficients vary by 9 orders of magnitude. We find that the variation is well explained by the existence of a steep surface mobility gradient and the anchoring of surface molecules at different depths. Quantitative analysis of these results supports a recently proposed double-exponential form for the mobility gradient: log D(T, z) = log Dv(T) + [log D0 − log Dv(T)]exp(−z/ξ), where D(T, z) is the depth-dependent diffusion coefficient, Dv(T) is the bulk diffusion coefficient, D0 ≈ 10−8 m2/s, and ξ ≈ 1.5 nm. Assuming representative bulk diffusion coefficients for these fragile glass formers, the model reproduces the presently known surface diffusion rates within 0.6 decade. Our result provides a general way to predict the surface diffusion rates in molecular glasses.
Analytical study on the dynamic characteristics of multiple gas-filled spherical bubbles in typical spatial locations
Authors: Qin Yupeng , Wang Zhen , Zou Li , Zong Zhi
Published: February 2022

The dynamic characteristics of multiple gas-filled spherical bubbles in three types of typical spatial locations are investigated analytically through a modified Rayleigh–Plesset equation. In the first type, two bubble centers form a one-dimensional straight line; the second type consists of any number of bubbles whose centers form a regular polygon in a two-dimensional plane; and in the third type, the bubble centers form a regular polyhedron in three-dimensional space. We show that physically these cases correspond qualitatively to periodic oscillations. Analytical expressions are derived for the maximum and minimum radii, based on which the oscillation amplitude and period are studied analytically. Parametric analytical solutions are also obtained. The influences of physical parameters on the multibubble motion are determined with the aid of these analytical results. We also study the limiting behavior of the analytical results for multiple bubbles, with the corresponding results for single bubbles being obtained as the distance between bubble centers approaches infinity.
Nonequilibrium free energy during polymer chain growth
Authors: Bley Michael , Dzubiella Joachim
Published: February 2022

During fast diffusion-influenced polymerization, nonequilibrium behavior of the polymer chains and the surrounding reactive monomers has been reported recently. Based on the laws of thermodynamics, the emerging nonequilibrium structures should be characterizable by some “extra free energy” (excess over the equilibrium Helmholtz free energy). Here, we study the nonequilibrium thermodynamics of chain-growth polymerization of ideal chains in a dispersion of free reactive monomers, using off-lattice, reactive Brownian dynamics computer simulations in conjunction with approximative statistical mechanics and relative entropy (Gibbs–Shannon and Kullback–Leibler) concepts. In the case of fast growing polymers, we indeed report increased nonequilibrium free energies ΔFneq of several kBT compared to equilibrium and near-equilibrium, slowly growing chains. Interestingly, ΔFneq is a non-monotonic function of the degree of polymerization and thus also of time. Our decomposition of the thermodynamic contributions shows that the initial dominant extra free energy is stored in the nonequilibrium inhomogeneous density profiles of the free monomer gas (showing density depletion and wakes) in the vicinity of the active center at the propagating polymer end. At later stages of the polymerization process, we report significant extra contributions stored in the nonequilibrium polymer conformations. Finally, our study implies a nontrivial relaxation kinetics and “restoring” of the extra free energy during the equilibration process after polymerization.
Real-time prediction framework for frequency-modulated multirotor noise
Authors: Ko Jeongwoo , Jeong Jaeheon , Cho Huisang , Lee Soogab
Published: February 2022

A comprehensive multirotor noise assessment framework is developed to predict the noise of rotational-speed-controlled rotor configurations in real-time. The key objectives are to synthesize the frequency-modulated multirotor noise and analyze the frequency modulation (FM) characteristics. The framework includes modules associated with the flight control, aerodynamics, time reconstruction, noise prediction, and time-frequency analysis (TFA). In addition to the hybrid blade element momentum model, the aerodynamics module contains a linear inflow model, a Beddoes wake model, and an unsteady aerodynamic correction model. The convective form and source-time dominant algorithms are used in the acoustic analogy for tonal noise prediction. The FM characteristics are identified using the synchrosqueezing-based high-resolution TFA for strongly non-stationary signals. The framework is verified through validation and verification studies for diverse rotor configurations and flight conditions. During the cruise flight of the multirotor, the tonal noise exhibits simultaneous frequency and amplitude modulations. In wind gust conditions, these modulations result from rotational speed variations, acoustic wave interference, and Doppler shifting. By clarifying the non-stationary noise signal in diverse flight environments, the proposed framework can facilitate noise assessment in the perception-influenced design stage of multirotor configurations.
Health care support following miscarriage in Australia: a qualitative study. How can we do better?
Authors: Yu Alice Y. , Temple-Smith Meredith J. , Bilardi Jade E.
Published: February 2022

Miscarriage occurs in one in four pregnancies in Australia and commonly results in adverse psychosocial sequelae, such as clinically significant levels of depression and anxiety. Women also commonly report a lack of support, understanding and acknowledgement of their loss. Research has shown that poor health care support experiences serve to exacerbate adverse psychosocial outcomes. This study explored the support experiences of women affected by miscarriage and their views on what support is needed, when it is needed and who should provide it, as well as their recommendations for improvement. Sixteen Australian women were purposively sampled to participate in qualitative semi-structured interviews. Interview data was analysed using content analysis. Approximately half the women reported positive experiences with healthcare providers, but, despite this, almost all pointed to areas where support was lacking. Insensitive comments and lack of emotional awareness were common. Participants suggested areas for increased clinician support, including mentioning the possibility of miscarriage earlier in routine pregnancies, offering more information before and at the time of miscarriage, providing emotionally sensitive care and offering follow up and psychological support. Women wanted healthcare providers to be proactive in offering support, information and emotionally sensitive care at the time of miscarriage, rather than having to seek it out themselves. Suggestions to improve support after miscarriage included mentioning the possibility of miscarriage earlier, offering more information about miscarriage and psychological support options.
In vivo imaging of the GnRH pulse generator reveals a temporal order of neuronal activation and synchronization during each pulse
Authors: Moore Aleisha M. , Coolen Lique M. , Lehman Michael N.
Published: February 2022

Significance

Hypothalamic oscillators that generate pulsatile patterns of hormone secretion represent a fundamental physiological feature regulating homeostatic systems. How individual cells within these neural ensembles generate and coordinate episodic activity and resultant pulse secretion is unknown. Recently, arcuate KNDy (kisspeptin/neurokinin B/dynorphin) cells were identified as a critical component of the gonadotrophin-releasing hormone (GnRH) pulse generator required for reproduction. Using in vivo calcium imaging of KNDy neurons in freely moving mice, we reveal that, prior to each GnRH pulse, individual KNDy cells demonstrate synchronized activity with striking temporal order, with subsets of cells behaving as “leaders” or “followers.” Future work to distinguish these novel subpopulations and define mechanisms underlying the temporal ordering of cellular synchronization may provide avenues to regulate pulse secretion.
Resettlement and Regeneration: The Pafuri Camp Joint-venture Lodge, Kruger National Park, South Africa
Authors: Spenceley Anna
Published: February 2022

This case describes how the Makuleke community reclaimed formal ownership over their land in the Kruger National Park through a land restitution process in South Africa. On the basis that the land could only be used for conservation, the Makuleke formed agreements with private operators to build and operate joint-venture tourism lodges. These generated income, employment and empowered people that had previously been forcibly removed from land by the state.

Information

Snyman, S. and Spenceley, A. (2019) Private Sector Tourism in Conservation Areas in Africa, CABI

© CAB International 2019
Dispersion of organic exciton polaritons—a novel undergraduate experiment
Authors: Rozenman Georgi Gary , Peisakhov Aron , Zadok Nir
Published: February 2022

We report on an innovative and simple way to perform an experiment which utilizes the properties of a quantized electromagnetic field coupled to Frenkel excitons in organic materials, forming exciton–polaritons (EP). We present an optical setup, which allowed to perform precise measurements of transmission of organic optical cavities at different angles of incidence and to study the dispersion relation of EP. We provided the full theoretical background of EP and demonstrated that the experimental results are in good agreement with theoretical predictions. Furthermore, we extracted the strong coupling strength and the excitonic–photonic weights of organic cavity samples.
Magnetic docking stations for remotely powered light emitting diodes
Authors: Helseth L E , Wen H Z
Published: February 2022

Light emitting diodes (LEDs) are efficient light sources which due to low power consumption often are considered for demonstrations of wireless energy transmission. It is often not only necessary to power these light sources wirelessly, but also to ensure that they conveniently dock at the correct position as effortlessly as possible without the need for chemical adhesives or mechanical attachment. In the current work a passive magnetic docking system which aids attachment of wirelessly powered LEDs is proposed. The system utilizes electromagnetic induction of nearby coils to power the LED. The spatial range of the magnetostatic interactions is controlled by the specific magnet arrangement used, such that the light is turned on either before or after docking is initiated. The constant and time-varying magnetic fields occupy the same volume, thus allowing the presenter to demonstrate the difference between magnetostatic interactions locking the LED in place and electromagnetic induction turning the LED on. It is demonstrated that the proposed system works well for light signaling in salt water, and may find use in wireless underwater communication.
Influence of source electrode metal work function on polar gate prompted source hole plasma in arsenide/antimonide tunneling interfaced junctionless TFET
Authors: Sharma Samriti , Chaujar Rishu
Published: February 2022

Numerous studies have explored the impact of control gate and polar gate (PG) on the retention of hole and electron charge plasma to induce the source and channel region polarity in junctionless tunnel field effect transistor (JLTFET). However, PG is not the only one responsible for the retention of hole plasma in the p+ prompted source but the hole plasma near the interface of source electrode metal (SEM) and p+ prompted source (SEM/S) is influenced by the choice of SEM work function too. This paper features a comprehensive investigation of the mutual significance of PG and SEM work function on p+ prompted source to study key analog characteristics of arsenide/antimonide tunneling interfaced hetero-material JLTFET (HJLTFET), which is unexplored in the literature otherwise. We have considered three metals—W (4.55 eV), Mo (4.65 eV), and Pd (5.3 eV) as the source electrodes in HJLTFET. For SEM work function lesser than p+ prompted source (W and Mo), the Schottky contact is formed by the depletion of hole plasma near SEM and p+ prompted source interface. This results in the immediate current inhibition at source to channel interface caused by an undesired movement of electrons en route to the Schottky interface. The Schottky tunneling phenomenon is considered by implementing the universal Schottky tunneling (UST) model to study the underestimated drain current of HJLTFET. However, the UST model becomes inconsequential for SEM work function higher than p+ prompted source (Pd) as hole plasma is preserved by the ohmic contact formation.
The effect of plasma discharge on methane diffusion combustion in air assisted by an atmospheric pressure microwave plasma torch
Authors: Li Shou-Zhe , Niu Yu-Long , Cao Shu-Li , Zhang Jiao , Zhang Jialiang , Li Xuechen
Published: February 2022

An atmospheric pressure air microwave plasma torch is employed to assist methane diffusion combustions using a combination of a combustor and burner. Experimentally, the effect of the air microwave plasma on combustion is investigated with respect to the flame morphology and the variation of gas components in the exhaust with the fuel equivalence ratio φ or the methane flow rate by comparing plasma-assisted combustion (PAC) and natural combustion (NC) without plasma application. The combustion degree of CH4 in PACs is found to be much enhanced in rich fuel combustion than in NC in both types of burners, which is measured by Fourier transformation infrared spectrometer (FTIR). In PACs, with the use of an air microwave plasma torch, the radicals originating from excitation, ionization, and dissociation of N2 and O2 and the high gas temperature induced in the plasma discharge play an important role in assisting the combustion.
Rational design of Fe-doped K0.8Ti1.73Li0.27O4@rGO as a high-rate and long-cycle-life anode for lithium-ion batteries
Authors: Hou Lijuan , Zhang Limin , Zang Jinhao , Shen Weixia , Zhang Taiyi , Huang Xiaowen , Yuan Huiyu , Kong Dezhi , Wang Ye , Li Xinjian , Xu Tingting
Published: February 2022

K0.8Ti1.73Li0.27O4 (KLTO) is an important titanium-based anode material for lithium-ion batteries (LIBs) and is expected to become an alternative to carbonaceous materials on account of its nontoxicity, low cost, and high safety performance. However, it suffers from poor specific capacity at high charge–discharge rates due to its low conductivity and obstructed Li-ion diffusion. In this work, an Fe-doped KLTO@rGO (Fe-KLTO@rGO) composite prepared by following a simple electrostatic assembly process and its high-rate and long-cycle-life-performance as an anode in LIBs is obtained. The Fe-KLTO@rGO composite sample has an excellent specific capacity of 330 and 105 mAh g−1 at a current density of 1 C (1 C = 175 mA g−1) and 50 C, respectively. In addition, the Fe-KLTO@rGO composite sample can carry out a long cycle of 3000 cycles at a rate of 50 C, and the specific capacity remains at 127 mAh g−1.
Large area, rapid, and protein-harmless protein–plasma-polymerized-ethylene coating with aerosol-assisted remote atmospheric-pressure plasma deposition
Authors: Yang Chu-Hao , Hsiao Chun-Ping , Chang Jerry , Lo Hsin-Yu , Cheng Yun-Chien
Published: February 2022

Our goal is to establish a remote-plasma-based aerosol-assisted atmospheric-pressure plasma deposition (RAAPD) system for depositing protein–plasma-polymerized-ethylene coatings. The method of RAAPD is using plasma to polymerize ethylene and add protein aerosol at downstream region to coat protein–plasma-polymerized-ethylene on substrate. We investigated effects of different mixing, mesh, deposition distance, gas flow, voltage, and frequency. Results showed that downstream-mixing method reduced heat effects on protein. The optimal coating was achieved when using mesh, at a close deposition distance, with high flow rate of protein aerosol, and under high voltage. Compared with current methods, impacts of RAAPD include reducing effects of plasma generated heat, reactive species, and UV on protein, and deposition will not be limited by electrode area and substrate material.
Phase-field simulation on the interaction of oxygen vacancies with charged and neutral domain walls in hexagonal YMnO3
Authors: Yang Chao , Sun Enwei , Liu Zhen , Zhang Xingru , Qi Xudong , Cao Wenwu
Published: February 2022

A three-dimensional model of the interaction between the charged or neutral domain walls and oxygen vacancies in the hexagonal manganite YMnO3 was proposed, and simulated using Landau–Ginzburg–Devonshire (LGD) theory, dynamic diffusion equation and Maxwell’s equation. The calculation proves that stiffness anisotropic factors can adjust the domain wall state and ultimately affect the distribution of oxygen vacancies. The head-to-head domain wall corresponds to low oxygen vacancy density, and the tail-to-tail domain wall corresponds to high oxygen vacancy density. The electrostatic field generated by the bound charge is the key factor leading to the change of oxygen vacancy distribution. Finally, e-index law N
d = ae

b*dP/dz
can fit the relationship between the oxygen vacancy concentration and the polarization gradient along z direction. Our theory provides a new way to modulate the distribution of oxygen vacancies through domain wall morphology in hexagonal YMnO3.
Redox-mediated C–C bond scission in alcohols adsorbed on CeO2−
x
thin films
Authors: Lykhach Yaroslava , Johánek Viktor , Neitzel Armin , Skála Tomáš , Tsud Nataliya , Beranová Klára , Mysliveček Josef , Brummel Olaf , Libuda Jörg
Published: February 2022

The decomposition mechanisms of ethanol and ethylene glycol on well-ordered stoichiometric CeO2(111) and partially reduced CeO2−x
(111) films were investigated by means of synchrotron radiation photoelectron spectroscopy, resonant photoemission spectroscopy, and temperature programmed desorption. Both alcohols partially deprotonate upon adsorption at 150 K and subsequent annealing yielding stable ethoxy and ethylenedioxy species. The C–C bond scission in both ethoxy and ethylenedioxy species on stoichiometric CeO2(111) involves formation of acetaldehyde-like intermediates and yields CO and CO2 accompanied by desorption of acetaldehyde, H2O, and H2. This decomposition pathway leads to the formation of oxygen vacancies. In the presence of oxygen vacancies, C–O bond scission in ethoxy species yields C2H4. In contrast, C–C bond scission in ethylenedioxy species on the partially reduced CeO2−x
(111) is favored with respect to C–O bond scission and yields methanol, formaldehyde, and CO accompanied by the desorption of H2O and H2. Still, scission of C–O bonds on both sides of the ethylenedioxy species yields minor amounts of accompanying C2H4 and C2H2. C–O bond scission is coupled with a partial recovery of the lattice oxygen in competition with its removal in the form of water.
Soft representation of the square-well and square-shoulder potentials to be used in Brownian and molecular dynamics simulations
Authors: Sandoval-Puentes Miguel A , Torres-Carbajal Alexis , Zavala-Martínez Arantza B , Castañeda-Priego Ramón , Méndez-Alcaraz José M
Published: February 2022

The discrete hard-sphere (HS), square-well (SW), and square-shoulder (SS) potentials have become the battle horse of molecular and complex fluids because they contain the basic elements to describe the thermodynamic, structural, and transport properties of both types of fluids. The mathematical simplicity of these discrete potentials allows us to obtain some analytical results despite the nature and complexity of the modeled systems. However, the divergent forces arising at the potential discontinuities may lead to severe issues when discrete potentials are used in computer simulations with uniform time steps. One of the few routes to avoid these technical problems is to replace the discrete potentials with continuous and differentiable forms built under strict physical criteria to capture the correct phenomenology. The match of the second virial coefficient between the discrete and the soft potentials has recently been successfully used to construct a continuous representation that mimics some physical properties of HSs (Báez et al 2018 J. Chem. Phys.
149 164907). In this paper, we report an extension of this idea to construct soft representations of the discrete SW and SS potentials. We assess the accuracy of the resulting soft potential by studying structural and thermodynamic properties of the modeled systems by using extensive Brownian and molecular dynamics computer simulations. Besides, Monte Carlo results for the original discrete potentials are used as benchmark. We have also implemented the discrete interaction models and their soft counterparts within the integral equations theory of liquids, finding that the most widely used approximations predict almost identical results for both potentials.
An enhanced variational mode decomposition based on correntropy and a periodicity-assisted log-cycligram for bearing fault diagnosis
Authors: Liu Chuliang , Tan Jianping
Published: February 2022

Variational mode decomposition (VMD) outperforms other decomposition methods in extracting fault-related modes. However, the major issue in the practical application of VMD is how to determine some key parameters appropriately, especially the mode number. To overcome this problem, an enhanced VMD is presented in this paper. A powerful tool, the rate of change of correntropy, is applied to estimate the mode number precisely. Then, the target mode is selected by a periodicity-assisted log-cycligram rather than conventional kurtosis. The advantages of the enhanced VMD are exposed by applying it to the experimental data collected from two different bearing test benches. Compared with the conventional fast kurtogram and empirical mode decomposition method, the enhanced VMD can extract the target fault mode from the collected vibration signal with strong background noise.
New traceability chain for spectral irradiance measurement at LNE-Cnam
Authors: Valin Mai Huong , Obein Gaël , Rougie Bernard , Valin Thierry , Truong Daniel , Vissiere Alain , Bourson Frédéric
Published: February 2022

LNE-Cnam has changed its traceability chain for measuring the spectral irradiance of a light source. This facility allows calibration of spectral irradiance of a standard lamp based on a comparison with a high temperature blackbody (HTBB). The reference spectral irradiance is determined by measuring the temperature of the HTBB with a filter radiometer calibrated against our radiant flux reference. This traceability scheme differs from the one used in our former setup, which was mainly based on the International Temperature Scale, ITS-90. Both principles are used in National Measurement Institutes. Our facility uses well known methods adapted to our best capabilities as well as a particular development in optical arrangement and filter radiometer calibration. Thanks to this new measurement setup, our spectral irradiance reference is now traceable to radiometric reference, i.e. our cryogenic radiometer. We have extended our measurement capability to cover the spectral range from 250 nm to 2500 nm. We have simplified the process by reducing the number of benches (three in one) and the number of operations, and we have designed a compact measuring setup through the use of a rotating integrative sphere. This allows us to reduce by at least a factor two our measurement uncertainties over almost the entire spectral range. With this new measurement facility, France participates in the ongoing CCPR k1.a key comparison. This is a key comparison of the Consultative Committee of Photometry and Radiometry for Spectral irradiance from 250 nm to 2500 nm of tungsten halogen lamps. This communication shows the method used, and its validation.
Conductivity measurement using 3D printed re-entrant cavity resonator
Authors: Mohammed Ali Musa , Wang Yi , Skaik Talal , Li Sheng , Attallah Moataz
Published: February 2022

A technique for measuring effective conductivity of conductor materials using 3D printed re-entrant cavity resonator is proposed. An analytical formula for the extraction of the effective conductivity has been derived in relation to energy stored in the volume of the cavity geometry. A method of resonant cavity characterisation of material based on microwave losses is utilised for the measurements. The approach offers a simplified analytical method and also supports the measurements of sample with arbitrary thickness. Samples produced from three different manufacturing processes of computer numerical control (CNC) and 3D printing, made of aluminium, copper and stainless steel were measured to demonstrate the method. The 3D printed and copper coated polymer sample is considered as reference material for the measurements. The measured results have shown that the copper coated polymer sample have similar conductivity with that CNC copper. This signifies the good finishing, low surface roughness and quality of copper coating used in 3D printed polymer device.
Atomic force microscopy characterization of polyethylene terephthalate grafting with poly(styrene sulfonate)
Authors: Nguyen Tuan Ngoc , Humblot Vincent , Migonney Véronique , Lévy Raphaël
Published: February 2022

Polyethylene terephthalate (PET) is widely used to elaborate biomaterials and medical devices in particular for long-term implant applications but tuning their surface properties remains challenging. We investigate surface functionalization by grafting poly(sodium 4-styrene sulfonate, PNaSS) with the aim of enhancing protein adhesion and cellular activity. Elucidating the topography and molecular level organization of the modified surfaces is important for understanding and predicting biological activity. In this work, we explore several grafting methods including thermal grafting, thermal grafting in the presence of Mohr’s salt, and UV activation. We characterize the different surfaces obtained using atomic force microscopy (AFM), contact angle (CA), and x-ray photoelectron spectroscopy (XPS). We observe an increase in the percentage of sulfur atoms (XPS) that correlates with changes in (CA), and we identify by AFM characteristic features, which we interpret as patches of polymers on the PET surfaces. This work demonstrates tuning of biomaterials surface by functionalization and illustrates the capability of AFM to provide insights into the spatial organization of the grafted polymer.
Valleytronics in two-dimensional materials with line defect
Authors: Tian Hongyu , Ren Chongdan , Wang Sake
Published: February 2022

The concept of valley originates from two degenerate but nonequivalent energy bands at the local minimum in the conduction band or local maximum in the valence band. Manipulating the valley states for information storage and processing develops a brand-new electronics—valleytronics. Broken inversion symmetry is a necessary condition to produce pure valley currents. The polycrystalline two-dimensional materials (graphene, silicene, monolayer group-VI transition metal dichalcogenides, etc) with pristine grains stitched together by disordered grain boundaries (GBs) are the natural inversion-symmetry-broken systems and the candidates in the field of valleytronics. Different from their pristine forms, the Dirac valleys on both sides of GBs are mismatched in the momentum space and induce peculiar valley transport properties across the GBs. In this review, we systematically demonstrate the fundamental properties of valley degree of freedom across mostly studied and experimentally feasible polycrystalline structure—the line defect, and the manipulation strategies with electrical, magnetic and mechanical methods to realize the valley polarization. We also introduce an effective numerical method, the non-equilibrium Green’s function technique, to tackle the valley transport issues in the line defect systems. The present challenges and the perspective on the further investigations of the line defect in valleytronics are also summarized.
Origin of proton induced fluorescence quenching of colloidal carbon dots: reshaping of Schrödinger wavefunctions and huge red shift of transition energy
Authors: Zhang Chengyu , Dai Dejian , Zhao Guo , Lu Wei , Fan Jiyang
Published: February 2022

The fluorescence quenching by protons is a universal phenomenon but the mechanism remains unclear. Here, we take the fluorescent amide-terminated carbon dots as a prototype to study the proton fluorescence quenching mechanism by using both experiments and time-dependent density functional theory calculations. The study reveals that when an approached proton is captured by the weakly negatively charged fluorophore group of the colloidal carbon dot, it will substantially change the electron wavefunctions owing to the strong proton–electron interaction, and this leads to highly diminished energy gap and resultant fluorescence quenching in the visible spectral region. The protons generated by hydrolysis of various types of metal ions also exhibit fruitful fluorescence quenching and the quenching efficiency is roughly proportional to the hydrolysis constant of the metal ion. This fluorescence quenching mechanism is quite distinct from the conventional ones involving electron or energy transfer.
Mg-doped InSnO nanofiber field-effect transistor for methanol gas detection at room temperature
Authors: Li Linkang , Li Jun , Fu Wenhui , Jiang Dongliang , Song Yanjie , Yang Qiuhong , Zhu Wenqing , Zhang Jianhua
Published: February 2022

Research on high-performance gas sensors for detecting toxic and harmful methanol gas is still a very important issue. For gas sensors, it is very important to be able to achieve low concentration detection at room temperature. In this work, we used the electrospinning method to prepare Mg-doped InSnO nanofiber field-effect transistors (FETs) methanol gas sensor. When the Mg element doping concentration is 2.3 mol.%, InSnO nanofiber FET exhibits excellent electrical properties, including higher mobility of 3.17 cm2 V−1 s−1, threshold voltage of 1.51 V, subthreshold swing of 0.42 V/decade, the excellent on/off current ratio is about 108 and the positive bias stress stability of the InSnO nanofiber FET through Mg doping has been greatly improved. In addition, the InSnMgO nanofiber FET gas sensor exhibits acceptable gas selectivity and sensitivity to methanol gas at room temperature. In the methanol gas sensor test at room temperature, when the methanol gas concentration is 60 ppm at room temperature, the response value of the InSnMgO nanofiber FET gas sensor is 81.92; and when the methanol concentration is 5 ppm, the response value is still 1.21. This work provides an effective and novel way to build a gas sensor at room temperature and use it to detect methanol gas at room temperature.
A physics-based machine learning approach for modeling the complex reflection coefficients of metal nanowires
Authors: Wu Xiaoqin , Wang Yipei
Published: February 2022

Metal nanowires are attractive building blocks for next-generation plasmonic devices with high performance and compact footprint. The complex reflection coefficients of the plasmonic waveguides are crucial for estimation of the resonating, lasing, or sensing performance. By incorporating physics-guided objective functions and constraints, we propose a simple approach to convert the specific reflection problem of nanowires to a universal regression problem. Our approach is able to efficiently and reliably determine both the reflectivity and reflection phase of the metal nanowires with arbitrary geometry parameters, working environments, and terminal shapes, merging the merits of the physics-based modeling and the data-driven modeling. The results may provide valuable reference for building comprehensive datasets of plasmonic architectures, facilitating theoretical investigations and large-scale designs of nanophotonic components and devices.
COREDIV modelling of nitrogen and krypton seeding at the ASDEX Upgrade tokamak
Authors: Ivanova-Stanik I , Zagórski R , Chomiczewska A , Bernert M , Glöggler S , Kallenbach A
Published: February 2022

Self-consistent core-scrape-off layer numerical simulations of an ASDEX-Upgrade discharge where the nitrogen (N) seeding is gradually replaced with the krypton (Kr) seeding during the plasma current flat-top phase are presented. These simulations are performed with the COREDIV code focusing on the prediction of the impurity evolution (W, Kr, N) with matched global plasma parameters: total and core radiation, temperature at the target plate and W concentration. The numerical results are compared with experimental measurements for shot #30503 at three different time points: 2.5 s (only N seeding), 4.2 s (N + Kr seeding) and 5.2 s (only Kr seeding). The calculated electron temperature at the divertor plate can be reduced to 3 eV with the highest Kr seeding. A good agreement between modelling results and experimental observations is reported.
Conventional and non-conventional diagnostics of a stable atmospheric pressure DC normal glow microplasma discharge intended for in situ TEM studies
Authors: Hansen Luka , Kohlmann Niklas , Schürmann Ulrich , Kienle Lorenz , Kersten Holger
Published: February 2022

A simple setup utilizing parallel flat electrodes with a 50–150 μm interelectrode distance divided by a Kapton spacer with a 1 mm diameter whole as discharge region intended for in situ transmission electron microscope studies is presented. The rather small setup operated in Ar or He results in an atmospheric pressure DC normal glow discharge and is investigated using various diagnostics. I–V characteristics show a glow-like behavior of the microplasma. Significant differences due to the working gas, electrode material and electrode distance have been observed. Currents in the range of 0.5–3 mA resulted in electrode potentials of 140–190 V for most experimental conditions. Optical emission spectroscopy and imaging revealed stable plasma operation and enabled the determination of current densities (approx. 16 mA mm−2 for He, or 28 mA mm−2 for Ar) independent of the input current as the discharge channel grows in diameter. Sheath thicknesses in the range of a few μm have been calculated by the collision-dominated Child–Langmuir law and trends are confirmed by the optical imaging. Energy flux measurements revealed a pronounced effect of ions on the measurement process and resulted in high energy fluxes locally up to 275 W cm−2. Effective secondary electron emission coefficients ranging from 1 to 1.6 depending on the discharge conditions have been determined based on the energy balance at the cathode.
Determining causality in Hall effect thrusters using extended convergent cross mapping: II*
Authors: Huerta C E , Martin R S , Eckhardt D Q , Koo J W
Published: February 2022

Extended convergent cross mapping was previously shown to be a powerful tool for analyzing the dynamics of Hall-effect thrusters and has applications in many diverse fields. Due to its limitations, data splitting and self-reconstruction are introduced for robustness, and the results are judiciously used to eliminate inconclusive and false links (sample scenarios are discussed). The analysis is then applied to Hall-effect thruster data, and the results are used to construct causality network graphs that map the flow of information inside the thruster. Two operating modes are studied: quiescent and oscillatory. For both cases, the causality links qualitatively agree with calculated plumes and demonstrate that charged particles carry information about the currents throughout the experiment, as expected. Causal links carried by neutral particles or propagating through waves are possible, but outside the scope of this work. Additionally, the extended convergent cross mapping results can be used to estimate the first two harmonic frequencies in the oscillatory mode to great precision
High performance 4H-SiC MOSFET with deep source trench
Authors: Na Jaeyeop , Cheon Jinhee , Kim Kwangsoo
Published: February 2022

In this study, we investigated a 4H-SiC deep source trench metal-oxide semiconductor field-effect transistor (DST-MOSFET) using technology computer-aided design numerical simulations. The proposed DST-MOSFET comprises a P-pillar formed along with the DST and a side P+ shielding region (SPR), which replaces the gate trench bottom SPR. Owing to the superjunction generated by the P-pillar and N-drift region, the static characteristics of the DST-MOSFET were superior to those of the trench gate MOSFET (UMOSFET) and double-trench MOSFET (DT-MOSFET). The specific on-resistance and Baliga’s figure of merit of DST-MOSFET improved by 9% and 104%, respectively, in comparison with those of UMOSFET; and by 37% and 64%, respectively, compared to those of DT-MOSFET. Additionally, the SPR reduced the gate-to-drain capacitance of the DST-MOSFET and improved the switching characteristics. Consequently, the total switching energy loss of the proposed DST-MOSFET reduced by 63% and 47% in comparison with those of the UMOSFET and DT-MOSFET, respectively.
Harvesting electrical energy from water drops falling on a vibrating cantilever
Authors: Helseth L E
Published: February 2022

In this work a novel thin-film device combining piezoelectric and contact electrification energy harvesting is created with the aim of investigating how it responds to water droplet impact during vibrations. The two energy harvesting principles utilize the same ground electrode, but the electrical signal outputs are independent and show entirely different electrical signal characteristics in presence of external forcing. While piezoelectricity gives rise to a nearly quadratic increase in harvested energy as a function of vibration velocity, the energy due to contact electrification reaches saturation for larger water drop velocities. On the other hand, when the water stream transitions from discrete droplets to a continuous stream the energy gathered from the piezoelectric mechanism exhibits saturation, whereas the energy due to contact electrification decreases. The proposed device may have applications as a self-powered environmental sensor that allow one to distinguish between forced oscillations and water droplet impacts.
Coda wave interferometry-based very early stage bolt looseness monitoring using a single piezoceramic transducer
Authors: Chen Dongdong , Shen Zhouhui , Fu Ruili , Yuan Bo , Huo Linsheng
Published: February 2022

The traditional monitoring methods can only give warnings for the bolts with severe looseness. However, it is essential for the safety of bolted joints to detect the looseness of bolts at the very early stage. To this end, in this paper, coda wave interferometry (CWI)-based high-resolution bolt preload monitoring using a single piezoceramic transducer is proposed. According to the CWI and acoustoelastic theories, a theoretical model is established and the linear relationship between the time shifts of coda waves and the preload variations of the bolt is derived. An experiment, in which a piezoceramic transducer simultaneously functions as the actuator and sensor, was carried out to verify the effectiveness of the proposed method. Three lead zirconium titanate transducers at different locations of a bolted specimen are tested. The experimental results show that the time shifts of coda waves increase linearly with the decrease of bolt preload and the detectable resolution of bolt preload (DRBP) is up to 0.326%. The DRBP value proves that the proposed technique can successfully monitor bolt looseness at the very early stage. In addition, a comparison study is carried out between the CWI-based method and the energy-based wavelet packet decomposition (WPD) method, and the result shows that the preload sensitivity of the CWI-based method is about six times higher than that of the WPD approach. Therefore, the CWI-based method is an effective way for the in situ monitoring of bolt looseness, especially in the embryonic stage.