bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solving curing-protocol-dependent shape errors in PDMS replication
Authors: Delplanque Emilie , Aymard Antoine , Dalmas Davy , Scheibert Julien 
Published: February 2022

Abstract
PolyDiMethylSiloxane (PDMS) is an elastomer increasingly used to produce soft objects by replication, in a variety of fields including soft electronics, microfluidics, tribology, biomechanics and soft robotics. While PDMS replication is usually considered faithful at all scales, down to nanoscales, detailed quantitative comparisons between the geometric features of the mold and the replicated object are still required to further ground this commonly accepted view. Here, we show that the top surface of centimetric parallelepipedic PDMS blocks, molded on a rigid plate, deviates from its expected flatness, the amplitude of the deviation being dependent on the crosslinking protocol. As a practical solution, we identify a suitable two-steps protocol which eliminates those replication errors. Using finite element simulations, we show that the effect originates from a thermal contraction when the sample cools from the curing temperature down to the operating temperature. This phenomenon actually applies at any length scale, and finely depends on the sample’s aspect ratio and boundary conditions. Our results should help mitigating replication errors in all applications where a well-defined sample geometry is required.
Surface acoustic wave quasi-Bessel beams generated by symmetrically tilted interdigital transducers
Authors: Ulug Bulent , Kuruoğlu Furkan , Yalçın Yeşim , Erol Ayşe , Sarcan Fahrettin , Şahin Ali , Cicek Ahmet 
Published: February 2022

Abstract
Formation of surface acoustic wave (SAW) quasi-Bessel beams on a piezoelectric substrate through superposition of plane waves generated by interdigital transducers tilted symmetrically about the propagation axis is numerically and experimentally demonstrated. Acting as an axicon, the tilted transducers provide a facile way for quasi-Bessel beam generation. Finite-element method simulations reveal that non-diffracting Bessel beams, whose length and width are 193 and 1.38 wavelengths, respectively, can be obtained on a YX-128∘ lithium niobate substrate for an axicon angle of 15 degrees. The corresponding values for 20 degrees are 146 and 1.05 wavelengths, respectively. For a wavelength of approximately 300 micrometers, transmission spectra show that Bessel beam formation can be achieved at frequencies around 13.3 MHz. Bessel beam is visualized through a thin liquid film of methanol on the substrate. SAW Bessel beams can be utilized in acoustophoresis in microfluidic systems and sensing applications.
Engineering Purcell factor anisotropy for dark and bright excitons in two dimensional semiconductors
Authors: Eswaramoorthy Lekshmi , Mokkapati Sudha , Kumar Anshuman 
Published: February 2022

Abstract
Tightly bound dark excitons in atomically thin semiconductors can be used for various optoelectronic applications including light storage and quantum communication. Their optical accessibility is however limited due to their out-of-plane transition dipole moment. We thus propose to strengthen the coupling of dark excitons in two dimensional materials with out-of-plane resonant modes of a cavity at room temperature, by engineering the anisotropy in the Purcell factor. A silica micro-disk characterised by high confinement of light in small modal volume, high Q-factor and free spectral range is used to couple to the excitons in monolayer transition metal dichalcogenides (TMDCs). We show numerically that the tapering of sidewalls of the micro-disk is an extremely versatile route for achieving the selective coupling of whispering gallery modes to light emitted from out-of-plane dipoles to the detriment of that from in-plane ones for four representative monolayer TMDCs.
Non-magnetic ion site disorder effects on the quantum magnetism of a spin-1/2 equilateral triangular lattice antiferromagnet
Authors: Huang Q , Rawl R , Xie W W , Chou E S , Zapf V S , Ding X X , Mauws C , Wiebe C R , Feng E X , Cao H B , Tian W , Ma J , Qiu Y , Butch N , Zhou H D 
Published: February 2022

Abstract
With the motivation to study how non-magnetic ion site disorder affects the quantum magnetism of Ba3CoSb2O9, a spin-1/2 equilateral triangular lattice antiferromagnet, we performed DC and AC susceptibility, specific heat, elastic and inelastic neutron scattering measurements on single crystalline samples of Ba2.87Sr0.13CoSb2O9 with Sr doping on non-magnetic Ba2+ ion sites. The results show that Ba2.87Sr0.13CoSb2O9 exhibits (i) a two-step magnetic transition at 2.7 K and 3.3 K, respectively; (ii) a possible canted 120 degree spin structure at zero field with reduced ordered moment as 1.24 μ
B/Co; (iii) a series of spin state transitions for both H∥ab-plane and H∥c-axis. For H∥ab-plane, the magnetization plateau feature related to the up–up–down phase is significantly suppressed; (iv) an inelastic neutron scattering spectrum with only one gapped mode at zero field, which splits to one gapless and one gapped mode at 9 T. All these features are distinctly different from those observed for the parent compound Ba3CoSb2O9, which demonstrates that the non-magnetic ion site disorder (the Sr doping) plays a complex role on the magnetic properties beyond the conventionally expected randomization of the exchange interactions. We propose the additional effects including the enhancement of quantum spin fluctuations and introduction of a possible spatial anisotropy through the local structural distortions.
Study of crystal properties based on attention mechanism and crystal graph convolutional neural network
Authors: Wang Buwei , Fan Qian , Yue Yunliang 
Published: February 2022

Abstract
The prediction of crystal properties has always been limited by huge computational costs. In recent years, the rise of machine learning methods has gradually made it possible to study crystal properties on a large scale. We propose an attention mechanism-based crystal graph convolutional neural network, which builds a machine learning model by inputting crystallographic information files and target properties. In our research, the attention mechanism is introduced in the crystal graph convolutional neural network (CGCNN) to learn the local chemical environment, and node normalization is added to reduce the risk of overfitting. We collect structural information and calculation data of about 36 000 crystals and examine the prediction performance of the models for the formation energy, total energy, bandgap, and Fermi energy of crystals in our research. Compared with the CGCNN, it is found that the accuracy (ACCU) of the predicted properties can be further improved to varying degrees by the introduction of the attention mechanism. Moreover, the total magnetization and bandgap can be classified under the same neural network framework. The classification ACCU of wide bandgap semiconductor crystals with a bandgap threshold of 2.3 eV reaches 93.2%, and the classification ACCU of crystals with a total magnetization threshold of 0.5 μ
B reaches 88.8%. The work is helpful to realize large-scale prediction and classification of crystal properties, accelerating the discovery of new functional crystal materials.
Band offset trends in IV–VI layered semiconductor heterojunctions
Authors: Wang Ying , Qiu Chen , Shen Chenhai , Li Lin , Yang Kaike , Wei Zhongming , Deng Hui-Xiong , Xia Congxin 
Published: February 2022

Abstract
The band offsets between semiconductors are significantly associated with the optoelectronic characteristics and devices design. Here, we investigate the band offset trends of few-layer and bulk IV–VI semiconductors MX and MX2 (M = Ge, Sn; X = S, Se, Te). For common-cation (anion) systems, as the atomic number increases, the valence band offset of MX decreases, while that of MX2 has no distinct change, and the physical origin can be interpreted using band coupling mechanism and atomic potential trend. The band edges of GeX2 system straddle redox potentials of water, making them competitive candidates for photocatalyst. Moreover, layer number modulation can induce the band offset of GeSe/SnS and GeSe2/GeS2 heterojunction undergoing a transition from type I to type II, which makes them suitable for optoelectronic applications.
A deep feature extraction approach for bearing fault diagnosis based on multi-scale convolutional autoencoder and generative adversarial networks
Authors: Hu Zhiyong , Han Taorui , Bian Jun , Wang Ziwei , Cheng Liu , Zhang Wenlei , Kong Xiangwei 
Published: February 2022

Abstract
The vibration signal of a bearing is closely related to its fault. The quality of the features extracted from the signal has a great impact on the accuracy of fault diagnosis. In this paper, a new method combining multi-scale autoencoder (AE) and generative adversarial network is proposed to extract the depth-sensitive features of the signal, and unite with the classifier for fault diagnosis. The AE is used as the generator (i.e. the generator is composed of encoder and decoder), and the idea of confrontation and reconstruction is used for training. The better the training of the generator, the better the training of the encoder, which means that the extracted feature of the encoder (the output of the encoder) is better. Then take these features as new inputs, send them to the classifier for classification, and finally get the fault type. This method solves the problems of weak representation and over-reliance on professional knowledge of the traditional method for bearing fault diagnosis. Meanwhile, compared with most existing neural network models for fault diagnosis, it has higher accuracy, especially in difficult diagnosis tasks. To further verify the effectiveness of the proposed model, a bearing test rig is established, and the collected data are used for fault diagnosis to prove the superiority of the proposed method.
Figures of merit of plasmon lattice resonance sensors: shape and material matters
Authors: Huang Xiaodan , Zhang Bo , Yu Bin , Zhang Hao , Shao Guojian 
Published: February 2022

Abstract
The figure of merit (FOM) of plasmon lattice resonance (PLR) sensors based on the array of metal/Si/SiO2 nanoparticles has been investigated. We demonstrate the shape and material of metal nanoparticles have remarkable effects on the PLR and FOM. FOM is governed by full-widths at half maximum (FWHM) and sensitivity of the PLR. Three different types of PLR can be generated by changing Ag nanoparticles’ shapes (pillars, cubes, spheres). One (named PLR1) is mainly originated from the coupling between Mie resonance of individual Si nanopillars and diffraction waves. PLR1 of Ag/Si/SiO2 nanoparticle arrays is limited in sensing applications due to lower intensity (for Ag pillars and Ag cubes), or smaller FOM (for Ag spheres). The other two are named PLR2. PLR2 of Ag/Si/SiO2 nanoparticle array with Ag pillars (or Ag cubes) is mainly originated from the coupling between the quadrupole resonance of individual Ag nanopillars (or Ag cubes) and diffraction waves. While PLR2 of Ag/Si/SiO2 nanoparticle array with Ag spheres is mainly originated from the coupling between dipole resonance of individual Ag nanospheres and diffraction waves. The optimal Ag nanoparticles’ shape in FOM is pillar due to the smallest FWHM of PLR2 of Ag/Si/SiO2 nanoparticle array with Ag pillars. Meanwhile, a comparison of FOM between Au, Ag and Al nanopillars of fixed size is made. The optimal material of metal nanopillars to obtain a high FOM is Ag due to higher sensitivity and narrower FWHM.
Strain and crystallite size controlled ordering of Heusler nanoparticles having high heating rate for magneto-thermal application
Authors: Karim Md Rejaul , Naryan Panda Surya , Barman Anjan , Sarkar Indranil 
Published: February 2022

Abstract
Heusler compound nanoparticles with good structural ordering need to be investigated as a potential material class for magneto-thermal applications requiring heat generation in presence of an oscillating magnetic field. Here, we report an important finding of a structural parameter related to the product of the strain and the coherent crystallite size, that can be used to efficiently control the structural ordering and the magnetic property of the Heulser compound nanoparticles. The optimization of this product parameter is found to enhance both the structural ordering and magnetic transition temperature in Co2FeSn Heusler nanoparticles. Furthermore, using magnetic hyperthermia measurements we demonstrate the possibility of heat generation using Heusler compound nanoparticles comparable to that of conventional magnetic nanoparticles. This shall lead to the development of Heulser compounds for similar applications.
Aligned deposition of bottom-up grown nanowires by two-directional pressure-controlled contact printing
Authors: Salimitari P , Behroudj A , Strehle S 
Published: February 2022

Abstract
Aligned large-scale deposition of nanowires grown in a bottom-up manner with high yield is a persisting challenge but required to assemble single-nanowire devices effectively. Contact printing is a powerful strategy in this regard but requires so far adequate adjustment of the tribological surface interactions between nanowires and target substrate, e.g. by microtechnological surface patterning, chemical modifications or lift-off strategies. To expand the technological possibilities, we explored two-directional pressure-controlled contact printing as an alternative approach to efficiently transfer nanowires with controlled density and alignment angle onto target substrates through vertical-force control. To better understand this technology and the mechanical behavior of nanowires during the contact printing process, the dynamic bending behavior of nanowires under varying printing conditions is modeled by using the finite element method. We show that the density and angular orientation of transferred nanowires can be controlled using this three-axis printing approach, which thus enables potentially a controlled nanowire device fabrication on a large scale.
On a 1D model with nonlocal interactions and mass concentrations: an analytical-numerical approach*
Authors: Abreu E , Ferreira L C F , Galeano J , Pérez J 
Published: February 2022

Abstract
We study global well-posedness and finite time blow-up of solutions for a nonlinear one-dimensional transport equation with nonlocal velocity

u

t

−

H

u

u

x

=
ν

u

x
x

, ν > 0, and measure initial data. Such model arises in fluid mechanics in vortex-sheet problems and its nonlocal feature comes from the presence of a singular integral operator (Hilbert transform

H

u

) in the velocity field. In the viscous case ν > 0, we analytically obtain an explicit condition on the size of the initial data for the global well-posedness in the framework of pseudomeasure spaces. In fact, we can give the condition depending on the initial-mass and analyze how the flow evolves from singular measures. Also, we numerically study blow-up of concentration type and global diffusion-smooth behavior of solutions. We obtain numerics that indicate the threshold value 2π for the initial-data mass that decides between blow-up or global smoothness of solutions. Such value is the same obtained for regular initial-data and by means of entropy methods. Thus, it seems to be intrinsic to the nonlocal PDE and independent of a particular framework, approach and initial-data regularity. The inviscid case ν = 0 is remarkable: simulations for model

u

t

−

H

u

u

x

=
0

, evidence that the solution presents blow-up of concentration type with mass-preserving, while an attenuation effect is observed for the model with opposite sign in the nonlinearity

u

t

+

H

u

u

x

=
0

, for any nontrivial (positive) measure as initial data.
Regularity and upper semicontinuity of pullback attractors for non-autonomous Rao–Nakra beam
Authors: Aouadi Moncef 
Published: February 2022

Abstract
In this paper we study the long-time dynamics of a non-autonomous Rao–Nakra sandwich beam. The governing equations of Rao–Nakra sandwich beam consist of two wave equations for the longitudinal displacements of the top and bottom layers, and one Euler–Bernoulli beam equation for the transversal displacement. Under quite general assumptions on nonlinear damping and sources terms and based on nonlinear semigroups and the theory of monotone operators, we establish existence and uniqueness of weak and strong solutions. We also establish a Lipschitz stability result. We prove the existence of pullback attractors in natural space energy. Finally, we prove the regularity of the family of pullback attractors and its upper semicontinuous with respect to the fractional exponent γ ∈ (0, 1/2).
Fully kinetic model of plasma expansion in a magnetic nozzle
Authors: Andrews Shaun , Di Fede Simone , Magarotto Mirko 
Published: February 2022

Abstract
A self-consistent model is presented for performing steady-state fully kinetic particle-in-cell simulations of magnetised plasma plumes. An energy-based electron reflection prevents the numerical pump instability associated with a typical open-outflow boundary, and is shown to be sufficiently general that both the plume kinetics and plasma potential demonstrate domain independence (within 6%). This is upheld by non-stationary Robin-type boundary conditions on the Poisson’s equation, coupled to a capacitive circuit that allows physical evolution of the downstream potential drop in the transient. The method has been validated against experiments, providing results that fall within the uncertainty of measurements. Simulations are then carried out to study collisional xenon discharges into axisymmetric diverging magnetic nozzles (MNs). Particular discussion is given to the identification of a collision-enhanced potential well arising from charge separation at the plume periphery, the role of ion–neutral charge exchange, and a three-region piecewise polytropic cooling regime for electrons. The polytropic index is shown to depend on the degree of magnetisation. Specifically, in the region near the thruster outlet, the plume is weakly-magnetised due to the cross-field diffusion of electron-heavy particle collisions. Downstream, a strongly-magnetised region of near-isothermal expansion occurs. Finally, in the detached region, the polytropic index tends to that of a more adiabatic unmagnetised case. With an increasing MN field strength, an inferior limit is found to the average polytropic index of

γ

¯

e

∼
1.16

.
Digitally manufactured air plasma-on-water reactor for nitrate production
Authors: Nieduzak Tymon B , Veng Visal , Prees Cameron N , Boutrouche Valentin D , Trelles Juan Pablo 
Published: February 2022

Abstract
The sustainable production of food to support the increasing world population is one of humanity’s most pressing challenges. Plasma activated water, produced using renewable energy, can help fulfill plants’ needs in sustainable agriculture approaches. The design, implementation, and characterization of a digitally manufactured air plasma-on-water reactor (POWR) for the synthesis of nitrate as green nitrogen fertilizer is presented. The interaction of air plasma-generated reactive oxygen and nitrogen species with water produces nitrate (NO3
−) and related species, which are the main nitrogen-containing nutrients for plants. The mild conditions of the operation of the POWR opens the possibility to use plastics, particularly through digital manufacturing strategies such as 3D-printing, for its fabrication. A pin-to-plate reactor configuration powered by high-voltage alternating power is chosen due to its simplicity and efficacy. A computational thermal-fluid model is used to evaluate the design and attain expected operational characteristics. The experimental characterization of the POWR encompassed design and operation parameters, namely electrode-water spacing, air flow rate, and voltage level. A machine learning approach is implemented to extract and quantify characteristic features of the plasma–water interaction, such plasma volume and plasma–water interface area. Experimental results revealed that the nitrate production rate varies linearly with dimensionless plasma volume. The design, fabrication, and characterization methods presented can be adapted to other POWRs and help enable on-demand nitrogen fertilizer production at low environmental and economic cost.
Bistable kinetic shades actuated with shape memory alloys: prototype development and daylight performance evaluation
Authors: Vazquez Elena , Duarte Jose P 
Published: February 2022

Abstract
Kinetic façade systems can adjust to different environmental conditions, thereby improving daylight performance in buildings. Bistable laminates present large deflections and can maintain their state without continuous energy supply, appealing features for kinetic applications. Nevertheless, these engineered materials have yet to be studied for their potential for improving daylight performance in buildings. This study sought to test the daylight performance of a kinetic bistable screen using a case study approach that combines experimental testing and building performance simulation. This paper details research to design and fabricate the shading screen and the experimental testing of the screens’ daylight performance. First, we focus on the design of a holder mechanism, which relies on a string system and shape memory alloys that actuate bistable flaps. Second, we experimentally collect data on daylight performance and compare it to simulation data to validate a daylight model. Results show that the designed bistable screen can increase the hours of adequate daylight throughout the year versus baseline cases, particularly when oriented south and east. The study suggests that bistable kinetic screens can help improve daylight performance in buildings.
Correlation of pseudogap, superconducting ordering and superconducting fluctuations with electron–phonon interactions in Bi2Sr2CaCu2O8+δ
Authors: Li Yong , Liang Weizheng , Li Ning , Chen Yongliang , Luo S N , Zhao Yong 
Published: February 2022

Abstract
The relationship between anomalous pseudogap and superconducting states is a fascinating but controversial subject in high temperature superconductors. Here, we investigate the different quasiparticle dynamics with femtosecond transient optical spectroscopy in underdoped Bi2Sr2CaCu2O8+δ
at 3–250 K. Below T
c, these results reveal the coexistence of the anomalous pseudogap and superconducting states. On the basis of the Mattis–Bardeen formula for the Cooper-pairing superconducting gap and the Kabanov model for the pseudogap state, the measurements yield a temperature-dependent superconducting gaps and two temperature-independent pseudogaps below and above the superconducting transition T
c. Above the superconducting transition temperature, the pseudogap state can be explained as an incipient condensation of Cooper pairs with short coherence length. The quasiparticle dynamics in the superconducting and pseudogap states are correlated well with electron–phonon interaction characteristics.
Light Sterile Neutrinos
Authors: Gariazzo Stefano 
Published: February 2022

Abstract
We review the status of light sterile neutrino searches, motivated by the original Short BaseLine (SBL) anomalies. Here, we discuss how sterile neutrino properties can be constrained by different types of neutrino oscillation experiments (considering appearance or disappearance probes in different oscillation channels) and non-oscillation measurements. These latter include experiments aiming at obtaining a value for the absolute scale of neutrino masses (β decay probes) and the indirect constraints that we could obtain from cosmological observations.