bluuebunny/crossref_metadata_2025 huggingface dataset:
OCELOT: An infrastructure for data-driven research to discover and design crystalline organic semiconductors
Authors: Ai Qianxiang , Bhat Vinayak , Ryno Sean M. , Jarolimek Karol , Sornberger Parker , Smith Andrew , Haley Michael M. , Anthony John E. , Risko Chad
Published: May 2021

Materials design and discovery are often hampered by the slow pace and materials and human costs associated with Edisonian trial-and-error screening approaches. Recent advances in computational power, theoretical methods, and data science techniques, however, are being manifest in a convergence of these tools to enable in silico materials discovery. Here, we present the development and deployment of computational materials data and data analytic approaches for crystalline organic semiconductors. The OCELOT (Organic Crystals in Electronic and Light-Oriented Technologies) infrastructure, consisting of a Python-based OCELOT application programming interface and OCELOT database, is designed to enable rapid materials exploration. The database contains a descriptor-based schema for high-throughput calculations that have been implemented on more than 56 000 experimental crystal structures derived from 47 000 distinct molecular structures. OCELOT is open-access and accessible via a web-user interface at https://oscar.as.uky.edu.
Inverse design of equilibrium cluster fluids applied to a physically informed model
Authors: Lindquist Beth A.
Published: May 2021

Inverse design strategies have proven highly useful for the discovery of interaction potentials that prompt self-assembly of a variety of interesting structures. However, often the optimized particle interactions do not have a direct relationship to experimental systems. In this work, we show that Relative Entropy minimization is able to discover physically meaningful parameter sets for a model interaction built from depletion attraction and electrostatic repulsion that yield self-assembly of size-specific clusters. We then explore the sensitivity of the optimized interaction potentials with respect to deviations in the underlying physical quantities, showing that clustering behavior is largely preserved even as the optimized parameters are perturbed.
Curvature-driven homogeneous Dzyaloshinskii–Moriya interaction and emergent weak ferromagnetism in anisotropic antiferromagnetic spin chains
Authors: Pylypovskyi Oleksandr V. , Borysenko Yelyzaveta A. , Fassbender Jürgen , Sheka Denis D. , Makarov Denys
Published: May 2021

Chiral antiferromagnets are currently considered for a broad range of applications in spintronics, spin-orbitronics, and magnonics. In contrast to the established approach relying on materials screening, the anisotropic and chiral responses of low-dimensional antiferromagnets can be tailored relying on the geometrical curvature. Here, we consider an achiral, anisotropic antiferromagnetic spin chain and demonstrate that these systems possess geometry-driven effects stemming not only from the exchange interaction but also from the anisotropy. Peculiarly, the anisotropy-driven effects are complementary to the curvature effects stemming from the exchange interaction and rather strong as they are linear in curvature. These effects are responsible for the tilt of the equilibrium direction of vector order parameters and the appearance of the homogeneous Dzyaloshinskii–Moriya interaction. The latter is a source of the geometry-driven weak ferromagnetism emerging in curvilinear antiferromagnetic spin chains. Our findings provide a deeper fundamental insight into the physics of curvilinear antiferromagnets beyond the σ-model and offer an additional degree of freedom in the design of spintronic and magnonic devices.
Screening silica-confined single-atom catalysts for nonoxidative conversion of methane
Authors: He Shu-Yue , Li Teng-Hao , Huang Zheng-Qing , Liu Yuan , Li Jun , Chang Chun-Ran
Published: May 2021

The development of a single-atom iron catalyst (Fe©SiO2) for the direct conversion of methane to olefins, aromatics, and hydrogen is a breakthrough in the field of nonoxidative conversion of methane (NCM). However, the optimization of the catalyst remains desirable for industrial applications. Herein, 25 transition metals, including Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Os, Ir, Pt, and Au, are selected to replace the central Fe atom for screening out better single-atom catalysts for the NCM. Using the performance on the activation of methane, such as the adsorption energy of methane, the dissociation energy, and the barrier of methane as the screening descriptors, Mn©SiO2, Fe©SiO2, W©SiO2, and Re©SiO2 are first screened out. The remarkable performance of the four catalysts on methane activation is attributed to the unique geometric structure and the dz2 orbitals of the central metal crossing over the Fermi level, which can benefit the interaction between methane and the catalysts. By considering the catalytic performance on the whole pathway of methane to ethylene, W©SiO2 is finally selected as the most active catalyst for the NCM, which has the lowest rate-determining barrier of 1.62 eV and the smallest free energy span (1.06 eV) of the overall catalytic cycle.
Coupling between interfacial strain and oxygen vacancies at complex-oxides interfaces
Authors: Aidhy Dilpuneet S. , Rawat Kanishk
Published: May 2021

The complex-oxides interfaces hold rich physics that have resulted in the emergence of various novel functional properties. While strain engineering has been widely used to induce many properties over the past decade, more recently the role of oxygen vacancies has increasingly drawn wider attention. In particular, research has revealed that there exists a strong coupling between strain and oxygen vacancy formation energy. This coupling can be used to alter oxygen vacancy concentration at interfaces, thereby opening another degree of freedom to control interfacial properties. In this review, we highlight recent works that have interrogated the connection between coupling and the emerging interfacial properties. The coupling has not only been used to selectively create oxygen vacancies at specific crystallographic oxygen sites but has also been used to manipulate ordering of oxygen vacancies near interfaces. In addition, recent studies have extended the existing connection between strain and octahedra distortion to oxygen vacancies, where the role of vacancies in the properties emerging due to octahedra distortion is now being unveiled. Finally, we discuss recent data-science efforts in the design and discovery of complex oxides and property prediction.
Optimization of four terminal rear heterojunction GaAs on Si interdigitated back contact tandem solar cells
Authors: Whitehead Riley C. , VanSant Kaitlyn T. , Warren Emily L. , Buencuerpo Jeronimo , Rienäcker Michael , Peibst Robby , Geisz John F. , Tamboli Adele C.
Published: May 2021

High-efficiency, four-terminal tandem solar cells composed of thin GaAs films mechanically stacked onto interdigitated back contact silicon solar cells with a glass interlayer are demonstrated. The optimal thickness of the absorber layer of a rear heterojunction GaAs subcell for use in four terminal tandem solar cells was studied. GaAs top cells with absorber layer thicknesses of 1.5, 1.9, 2.3, 2.8, and 3.5 μm were fabricated on glass and mechanically stacked onto interdigitated back-contact Si bottom cells. All tandem cells were found to have efficiencies above 30% under the AM1.5 G spectrum demonstrating a relatively weak sensitivity to thickness in the four-terminal configuration. We found the 2.8 μm absorber layer cell to have the highest top cell and tandem cell efficiency at 26.38% and 32.57%, respectively. Optical modeling with transfer matrix method for the planar top cell and Lambertian light trapping in the textured Si subcell, along with drift-diffusion Hovel equations, were used to show photon recycling enhancement to the effective diffusion length and VOC of the top cell as a result of the low-index glass interlayer.
Designing antiviral surfaces to suppress the spread of COVID-19
Authors: Chatterjee Sanghamitro , Murallidharan Janani Srree , Agrawal Amit , Bhardwaj Rajneesh
Published: May 2021

Surface engineering is an emerging technology to design antiviral surfaces, especially in the wake of COVID-19 pandemic. However, there is yet no general understanding of the rules and optimized conditions governing the virucidal properties of engineered surfaces. The understanding is crucial for designing antiviral surfaces. Previous studies reported that the drying time of a residual thin-film after the evaporation of a bulk respiratory droplet on a smooth surface correlates with the coronavirus survival time. Recently, we [Chatterjee et al., Phys. Fluids. 33, 021701 (2021)] showed that the evaporation is much faster on porous than impermeable surfaces, making the porous surfaces lesser susceptible to virus survival. The faster evaporation on porous surfaces was attributed to an enhanced disjoining pressure within the thin-film due the presence of horizontally oriented fibers and void spaces. Motivated by this, we explore herein the disjoining pressure-driven thin-film evaporation mechanism and thereby the virucidal properties of engineered surfaces with varied wettability and texture. A generic model is developed which agrees qualitatively well with the previous virus titer measurements on nanostructured surfaces. Thereafter, we design model surfaces and report the optimized conditions for roughness and wettability to achieve the most prominent virucidal effect. We have deciphered that the optimized thin-film lifetime can be gained by tailoring wettability and roughness, irrespective of the nature of texture geometry. The present study expands the applicability of the process and demonstrates ways to design antiviral surfaces, thereby aiding to mitigate the spread of COVID-19.
First principles inelastic mean free paths coupled with Monte Carlo simulation of secondary electron yield of Cu-Ni, Cu-Zn, and Mo-Li
Authors: Gutierrez Raul E. , Matanovic Ivana , Polak Maciej P. , Johnson Ryan S. , Morgan Dane , Schamiloglu Edl
Published: May 2021

Secondary electron yield (SEY) is relevant for widely used characterization methods (e.g., secondary electron spectroscopy and electron microscopy) and materials applications (e.g., multipactor effect). Key quantities necessary for understanding the physics of electron transport in materials and simulation of SEY are electron mean free paths (MFPs). This paper explores the impact of alloying on MFPs and SEY for Cu-Ni, Cu-Zn, and Mo-Li alloys relative to their component metals Cu, Ni, Zn, Mo, and Li. Density functional theory calculations yield density of states, Fermi energy, work function, and frequency- and momentum-dependent energy loss function. These material properties were used to calculate MFPs and Monte Carlo simulations were performed to obtain energy dependent SEY for the alloys as well for the component metals. The results show that MFPs and SEYs of the studied alloys lie between those of component pure elements but are not a simple composition weighted average. Detailed analysis of the secondary electron generation and emission process shows that the changes in the SEY of alloys relative to the SEY of their component metals depend on the changes in both electronic structure and dielectric properties of the material.
Three-state harmonic models for photoinduced charge transfer
Authors: Brian Dominikus , Liu Zengkui , Dunietz Barry D. , Geva Eitan , Sun Xiang
Published: May 2021

A widely used strategy for simulating the charge transfer between donor and acceptor electronic states in an all-atom anharmonic condensed-phase system is based on invoking linear response theory to describe the system in terms of an effective spin-boson model Hamiltonian. Extending this strategy to photoinduced charge transfer processes requires also taking into consideration the ground electronic state in addition to the excited donor and acceptor electronic states. In this paper, we revisit the problem of describing such nonequilibrium processes in terms of an effective three-state harmonic model. We do so within the framework of nonequilibrium Fermi’s golden rule (NE-FGR) in the context of photoinduced charge transfer in the carotenoid–porphyrin–C60 (CPC60) molecular triad dissolved in explicit tetrahydrofuran (THF). To this end, we consider different ways for obtaining a three-state harmonic model from the equilibrium autocorrelation functions of the donor–acceptor, donor–ground, and acceptor–ground energy gaps, as obtained from all-atom molecular dynamics simulations of the CPC60/THF system. The quantum-mechanically exact time-dependent NE-FGR rate coefficients for two different charge transfer processes in two different triad conformations are then calculated using the effective three-state model Hamiltonians as well as a hierarchy of more approximate expressions that lead to the instantaneous Marcus theory limit. Our results show that the photoinduced charge transfer in CPC60/THF can be described accurately by the effective harmonic three-state models and that nuclear quantum effects are small in this system.
Torsional wave focusing in cylindrical structures with the conformal gradient-index phononic crystal lens
Authors: Okudan Gorkem , Danawe Hrishikesh , Ozevin Didem , Tol Serife
Published: May 2021

We present torsional wave focusing in cylindrical structures integrated with conformal gradient-index phononic crystal (GRIN-PC) lenses. The mechanical lens modifies the refractive characteristics of propagating waves along the axial direction such that the torsional wave energy focuses at a desired point with an increased amplitude. In this paper, our main goal is to exploit the GRIN-PC concept for amplification of the fundamental torsional wave mode, namely, T(0,1), which is especially favorable in the guided wave ultrasonic testing of pipelines and can extend important structural information over long-range pipelines. To this end, we first study d35 piezoelectric transducer arrays through multiphysics simulations coupling piezoelectric and solid mechanics models and determine the optimal number of transducers to achieve the excitation of torsional plane wave. Two-dimensional Fourier transform as well as the tangential displacement histories around the pipe circumference at various axial positions verify the pure T(0,1) excitation, which is validated with experiments. Next, we design, fabricate, and numerically and experimentally study the conformal GRIN-PC for T(0,1) mode focusing in a range of ultrasonic frequencies, from 30 to 50 kHz. Measurements show that the amplitude of the torsional wave mode is amplified by 39% at the focal point with the presence of the GRIN-PC lens.
Printability regimes of pure metals using contactless magnetohydrodynamic drop-on-demand actuation
Authors: Sukhotskiy Viktor , Tawil Kareem , Einarsson Erik
Published: May 2021

We demonstrate a computational study used to evaluate drop-on-demand printability of liquid metals via a contactless magnetohydrodynamic (MHD) pumping method. We show that the ejection regimes of pure liquid metal droplets can be categorized using two dimensionless quantities: We and a new dimensionless quantity S=Ha2Ca. By plotting We vs S, a linear relationship emerges which relates the velocity through the ejection orifice to the applied magnetic flux density. Additionally, satellite-free droplet generation is shown to be bounded by the ranges 1000≲S≲2000 and 10≲We≲20. These ranges, coupled with the linear We vs S relationship, allow one to predict the critical magnetic flux necessary to eject a satellite-free liquid metal droplet for any liquid metal with a very low viscosity to surface tension ratio (Oh<0.005). We discuss the physics underlying the MHD ejection process and relate the pump action to the dimensionless quantities. We use an MHD finite element model to parametrically sweep through applied magnetic fields and explore two-phase ejection of Al, Cu, Fe, Li, Sn, Ti, Zn, and Zr droplets from a 200 μm orifice. The model is validated using experimental high speed video ejection of Zn and Al, and the reported relationship between We and S can be used to connect the input flux density to the resulting ejection regime.
Graded buffer Bragg reflectors with high reflectivity and transparency for metamorphic optoelectronics
Authors: France R. M. , Buencuerpo J. , Bradsby M. , Geisz J. F. , Sun Y. , Dhingra P. , Lee M. L. , Steiner M. A.
Published: May 2021

A graded buffer Bragg reflector (GBBR) is a bifunctional device component that provides the reflection of a distributed Bragg reflector and the adjustable lattice constant of a compositionally graded buffer. Prior work showed that these properties can be combined with low threading dislocation density and high reflectivity. Here, we design and demonstrate complex GBBRs for specific metamorphic solar cell applications. We design buffers that provide (1) high reflectivity over a narrow bandwidth, for quantum well solar cells, (2) reflectivity over a wide bandwidth, for optically thin solar cells, and (3) low sidelobe reflection, for multijunction devices that demand low out-of-band reflection. Apodized and triple GBBRs are demonstrated, and transparency is always considered, requiring designs with carefully engineered material combinations. A GBBR with a reflection of 99% is demonstrated, as well as a triple GBBR that has over 80% reflection for 100 nm of the spectrum around 800 nm. We also analyze potential deviations in a baseline GBBR from that of a perfect DBR using transmission electron microscopy to analyze imperfections in the material and modeling to analyze the impact of imperfect refractive index data for lattice-mismatched AlGaInAs. Minimal crosshatch roughness and unintentional thickness variation occur throughout the buffer, which likely influences reflection slightly. Small deviations between the calculated AlGaInAs and utilized AlGaAs refractive index exist, giving methods for future GBBR improvement. While the GBBR designs are intended for metamorphic solar cells, the broad and high reflection may also be useful for other optoelectronic devices such as light-emitting diodes or lasers.
Chaotic transients, riddled basins, and stochastic transitions in coupled periodic logistic maps
Authors: Bashkirtseva Irina , Ryashko Lev
Published: May 2021

A system of two coupled map-based oscillators is studied. As units, we use identical logistic maps in two-periodic modes. In this system, increasing coupling strength significantly changes deterministic regimes of collective dynamics with coexisting periodic, quasiperiodic, and chaotic attractors. We study how random noise deforms these dynamical regimes in parameter zones of mono- and bistability, causes “order–chaos” transformations, and destroys regimes of in-phase and anti-phase synchronization. In the analytical study of these noise-induced phenomena, a stochastic sensitivity technique and a method of confidence domains for periodic and multi-band chaotic attractors are used. In this analysis, a key role of chaotic transients and geometry of “riddled” basins is revealed.
Stoichiometric silicon nitride thin films for gas barrier, with applications to flexible and stretchable OLED encapsulation
Authors: Shin SeungMin , Yoon Ho Won , Jang YunSung , Hong MunPyo
Published: May 2021

This study reveals that the stoichiometricity of silicon nitride thin films (SiNx-TFs) significantly governs the packing density and water vapor transmission rate (WVTR), and it can be controlled by chemical reactions accompanied by the removal of oxygen impurities with a nitrogen neutral beam (N-NB). Here, oxygen contents of SiNx-TFs are reduced through the formation of volatile NOx, and their amount is dominated by the energy of the N-NB reflected from a negatively biased reflector (0 to −60 V). The single-layered stoichiometric SiNx-TFs with a thickness of 100 nm provides the WVTR of 6.2 × 10−6 g/(m2day), with a density and composition ratio of N/Si stoichiometry at 3.13 g/cm3 and 1.33, respectively. This optimized SiNx-TF encapsulated top-emission organic light-emitting diode has reliability under harsh condition (85 °C and 85% relative humidity) for 830 h or more.
PI(3,4)P2-mediated membrane tubulation promotes integrin trafficking and invasive cell migration
Authors: Feng Zhen , Yu Cheng-han
Published: May 2021

Significance

The dynamic distribution of phosphoinositide lipids orchestrates intracellular compartmentalization and protein sorting. Here, we report the PI(3,4)P2-dependent endocytosis of adhesion receptor integrin-beta3 at the invadopodium and its implication in promoting invasive cell migration. PI(3,4)P2-rich compartment in the plasma membrane contains integrin-beta3 and is actively internalized through SNX9-mediated membrane invagination as well as dynein-mediated membrane tubulation along cortical microtubule tracks. Accelerated integrin endocytosis promotes adhesion turnover, and subsequent integrin exocytosis further supports cell migration. In general, the functional link between PI(3,4)P2biogenesis and membrane internalization can be applicable to other membrane molecules at the invadopodium and provide insights into the regulation of cell migration.
CAG RNAs induce DNA damage and apoptosis by silencing
NUDT16
expression in polyglutamine degeneration
Authors: Peng Shaohong , Guo Pei , Lin Xiao , An Ying , Sze Kong Hung , Lau Matthew Ho Yan , Chen Zhefan Stephen , Wang Qianwen , Li Wen , Sun Jacquelyne Ka-Li , Ma Sum Yi , Chan Ting-Fung , Lau Kwok-Fai , Ngo Jacky Chi Ki , Kwan Kin Ming , Wong Chun-Ho , Lam Sik Lok , Zimmerman Steven C. , Tuccinardi Tiziano , Zuo Zhong , Au-Yeung Ho Yu , Chow Hei-Man , Chan Ho Yin Edwin
Published: May 2021

Significance

Small CAG (sCAG) RNAs are neurotoxic, but their role in polyglutamine degeneration remains to be fully elucidated. We observed that cellular expression of sCAGs is sufficient to induce neuronal DNA damage and discovered that the transcript level of
NUDT16
was reduced in HD models. The NUDT16 protein has previously been linked to the DNA damage pathway. At the structural level, sCAGs form double-stranded CAG–CUG heteroduplex RNA with
NUDT16
transcript which led to its gene silencing. We showed that the bisamidinium-based compound DB213 specifically interacts with duplex CAG RNA; consequently, both
NUDT16
expression and DNA damage were rescued in HD mice. Our findings describe a pathogenic pathway that induces DNA damage in polyglutamine degeneration and demonstrate its therapeutic potential.
ICAM-1 induced rearrangements of capsid and genome prime rhinovirus 14 for activation and uncoating
Authors: Hrebík Dominik , Füzik Tibor , Gondová Mária , Šmerdová Lenka , Adamopoulos Athanassios , Šedo Ondrej , Zdráhal Zbyněk , Plevka Pavel
Published: May 2021

Significance

Medical visits and missed days of school and work caused by rhinoviruses cost tens of billions of US dollars annually. Currently, there are no antivirals against rhinoviruses, and the available treatments only treat the symptoms. Here, we present the molecular structure of human rhinovirus 14 in complex with its cellular receptor intercellular adhesion molecule 1. The binding of the virus to its receptor initiates the infection. Knowledge of the structure of the human rhinovirus 14–intercellular adhesion molecule 1 interface and mechanism of interaction provides the basis for the design of compounds that may block the binding of rhinoviruses to receptors and thus prevent infection.
Poa annua (annual meadowgrass).
Authors: Rojas-Sandoval Julissa , Acevedo-Rodríguez Pedro
Published: May 2021

P. annua is a cosmopolitan grass included in the Global Compendium of Weeds (Randall, 2012) and listed as one of the most aggressive weeds invading areas from sea level up to 1200 m in elevation. It can be found from Arctic to the Antarctic regions in practically all terrestrial ecosystems (Holm et al., 1997; USDA-ARS, 2014). It is listed as a weed in 38 crops in more than 80 countries within and outside its native distribution range. It grows in a wide variety of soils, tolerates trampling, mowing, and frozen conditions, and is a frequent weed in areas heavily trafficked by livestock or humans. This species has the potential to outcompete other plants and crops (Holm et al., 1997).
Black holes and wormholes in f(R) gravity with a kinetic curvature scalar
Authors: Chervon Sergey V , Fabris Júlio C , Fomin Igor V
Published: May 2021

We study the chiral self-gravitating model (CSGM) of a special type in the spherically symmetric static spacetime in Einstein frame. Such CSGM is derived, by virtue of Weyl conformal transformation, from a gravity model in the Jordan frame corresponding to a modified f(R) gravity with a kinetic scalar curvature. We investigate the model using harmonic coordinates and consider a special case of the scaling transformation from the Jordan frame. We find classes of solutions corresponding to a zero potential and we investigate horizons, centers and the asymptotic behavior of the obtained solutions. Other classes of solutions (for the potential not equal to zero) are found using a special relation (ansatz) between the metric components. Investigations of horizons, centers and asymptotic behavior of obtained solutions for this new case are performed as well. Comparative analysis with similar solutions obtained earlier in literature is made.
Strong-field triple ionisation of atoms with p
3 valence shell
Authors: Prauzner-Bechcicki Jakub S , Efimov Dmitry K , Mandrysz Michał , Zakrzewski Jakub
Published: May 2021

The interaction of strong pulsed femtosecond laser field with atoms having three equivalent electrons in the outer shell (p
3 configuration, e.g. nitrogen) is studied via numerical integration of a time-dependent Schrödinger equation on a spatial grid. Single ionisation, double ionisation (DI) and triple ionisation (TI) yields originating from a completely antisymmetric wave function are calculated and extracted using a restricted-geometry model with the soft-core potential and three active electrons. The observed suppression of the ionisation yields for the non-sequential processes, in both DI and TI cases, is attributed to the action of the Pauli principle. Compared against earlier results investigating the s
2
p
1 configuration, we propose that the differences found here might in fact be accessible through electron’s momentum distribution.
Non-equilibrium modeling of arc plasmas in the gas–metal arc–welding process
Authors: Eda Satoshi , Ogino Yosuke , Asai Satoru , Sano Tomokazu
Published: May 2021

In recent years, the thermal and chemical non-equilibrium properties of arc plasmas have been among the most critical topics in the modeling of welding arcs. Non-equilibrium phenomena can be observed in the near-electrode regions, where the characteristics of the arc are determined. Although non-equilibrium modeling should contribute to a deeper understanding of the gas–metal arc-welding (GMAW) process, no non-equilibrium model has been reported for GMAW processes, while several models have been reported for gas–tungsten arc-welding processes. In this study, we attempted to elucidate the non-equilibrium phenomena in the GMAW process. In addition, as a first step, we developed a non-equilibrium model of the arc plasma in the GMAW process. The influence of the iron vapor was successfully determined by our model. We then inferred that the concentration of iron vapor affects the number density of electrons and, consequently, the thermal equilibrium of the arc in the GMAW process.
The correlation between limiting efficiency of indoor photovoltaics and spectral characteristics of multi-color white LED sources
Authors: Zheng Chaodan , Wu Qingfeng , Guo Shouhui , Huang Weijun , Xiao Qing , Xiao Wei
Published: May 2021

The correlation between the optimal performance of indoor photovoltaics (IPVs) and spectral characteristics of white light-emitting diode (LED) sources has been investigated theoretically. We calculated the Schockley–Queisser limit of IPVs under multi-color white LEDs with different correlated color temperature (CCT), color rendering index (CRI) and luminous efficacy of radiation (LER). It is found that the optimal bandgap for an IPV cell is not only influenced by CCT, but also by LER and CRI. However, the main factor that affects the maximum power conversion efficiency (PCE) is CCT, and the maximum PCE is relatively independent of the CRI and LER under the same condition of CCT. The maximum PCE decreases with the increase of CCT. Based on the analysis of the energy loss within IPVs, it is found that the value of the optimal bandgap is sensitive to the fraction of red light in the spectrum of white LEDs. The maximum PCE is primarily limited by the relaxation to band edge loss, which is caused by the high-energy blue or cyan light in the spectrum of white LEDs.
Formation of dislocations via misfit strain across interfaces in epitaxial BaTiO3 and SrIrO3 heterostructures
Authors: Saghayezhian M , Wang Z , Howe D , Siwakoti P , Plummer E W , Zhu Y , Zhang Jiandi
Published: May 2021

Dislocations often occur in thin films with large misfit strain as a result of strain energy accumulation and can drastically change the film properties. Here the structure and dislocations in oxide heterostructures with large misfit strain are investigated on atomic scale. When grown on SrTiO3 (001), the dislocations in both the monolithic BaTiO3 thin film and its superlattices with SrIrO3 appear above a critical thickness around 6 nm. The edge component of the dislocations is seen in both cases with the Burgers vector of
a
⟨100⟩. However, compared to monolithic BaTiO3, the dislocation density is slightly lower in BaTiO3/SrIrO3 superlattices. In the superlattice, when considering the SrTiO3 lattice constant as the reference, BaTiO3 has a larger misfit strain comparing with SrIrO3. It is found that in both cases, the formation of dislocation is only affected by the critical thickness of the film with larger lattice misfit (BaTiO3), regardless of the existence of a strong octahedral tilt/rotation mismatch at BaTiO3/SrIrO3 interface. Our findings suggest that it is possible to control the position of dislocations, an important step toward defect engineering.
Controlling unconventional superconductivity in artificially engineered f-electron Kondo superlattices
Authors: Naritsuka M , Terashima T , Matsuda Y
Published: May 2021

Unconventional superconductivity and magnetism are intertwined on a microscopic level in a wide class of materials, including high-T
c cuprates, iron pnictides, and heavy-fermion compounds. Interactions between superconducting electrons and bosonic fluctuations at the interface between adjacent layers in heterostructures provide a new approach to this most fundamental and hotly debated subject. We have been able to use a recent state-of-the-art molecular-beam-epitaxy technique to fabricate superlattices consisting of different heavy-fermion compounds with atomic thickness. These Kondo superlattices provide a unique opportunity to study the mutual interaction between unconventional superconductivity and magnetic order through the atomic interface. Here, we design and fabricate hybrid Kondo superlattices consisting of alternating layers of superconducting CeCoIn5 with d-wave pairing symmetry and nonmagnetic metal YbCoIn5 or antiferromagnetic heavy fermion metals such as CeRhIn5 and CeIn3. In these Kondo superlattices, superconducting heavy electrons are confined within the two-dimensional CeCoIn5 block layers and interact with neighboring nonmagnetic or magnetic layers through the interface. Superconductivity is strongly influenced by local inversion symmetry breaking at the interface in CeCoIn5/YbCoIn5 superlattices. The superconducting and antiferromagnetic states coexist in spatially separated layers in CeCoIn5/CeRhIn5 and CeCoIn5/CeIn3 superlattices, but their mutual coupling via the interface significantly modifies the superconducting and magnetic properties. The fabrication of a wide variety of hybrid superlattices paves a new way to study the relationship between unconventional superconductivity and magnetism in strongly correlated materials.
Measurement uncertainty of a measurement system for dynamic pressure in the kbar regime
Authors: Slanina O , Wynands R
Published: May 2021

We have characterized the measurement uncertainty of a setup for the dynamic measurement of pressure pulses with amplitudes in the low kbar range and with millisecond duration. The uncertainty is closely proportional to pressure, with a magnitude of 0.34% (coverage factor k = 1). In particular, we treat the safety-critical application of measuring the pressure inside an ammunition cartridge during firing, where a target uncertainty of 3% has been set by the Permanent International Commission for the Proof of Small Arms.
Phononic-fluidic cavity sensors for high-resolution measurement of concentration and speed of sound in liquid solutions and mixtures
Authors: Lucklum Frieder
Published: May 2021

A phononic-fluidic cavity sensor is a new type of acoustic fluid sensor to measure volumetric liquid properties. In our work, it consists of solid-air 3D phononic crystal (PnC) layers confining a fluidic cavity resonator to generate a strong, well separated cavity resonance within the phononic band gap. This allows for the measurement of changes in speed of sound of a liquid analyte with very high, linear sensitivity. In this work, we present theoretical and experimental results for very sensitive determination of sodium chloride and glucose concentrations in aqueous solutions. The 3D-printed measurement cell consists of a rectangular liquid chamber surrounded by an optimized PnC with a simple cubic ball and beam design acting as a metamaterial combining Bragg and local resonance scattering to create optimal boundary conditions for the liquid cavity resonator. Analytical transmission line modeling is used to illustrate the working principle of the sensor. Numerical finite element models describe the phononic band structure and transmission behavior, as well as the frequency response of the sensor element at different mass fractions of the sample solutions as validation for our experiments. A high sensitivity of concentration and subsequently speed of sound is demonstrated over a very large concentration range of 0%–30%.
Pterostilbene nanoparticles with small particle size show excellent anti-breast cancer activity in vitro and in vivo
Authors: Zou Yuan , Wang Xiangtao , Bi Dongdong , Fu Jingxin , Han Jianwei , Guo Yifei , Feng Li , Han Meihua
Published: May 2021

Pterostilbene (PTE) is known as resveratrol of the next generation and it has attracted extensive attention in recent years. PTE can inhibit the growth of a variety of tumor cells. To overcome the problem of insolubility, PTE was loaded into nanoparticles (NPs) by anti-solvent precipitation technique using soybean lecithin (SPC) and D-α-tocopheryl polyethylene glycol succinate (TPGS) as stabilizers. The obtained PTE-NPs had an average particle size of 71.0 nm, a polydispersity index （PDI） value of 0.258, and a high zeta potential of −40.8 mV. PTE-NPs can maintain particle size stability in various physiological media. The entrapment efficiency of PTE-NPs was 98.24%. And the apparently water solubility of PTE-NPs was about 53 times higher than the solubility of PTE (54.41 μg ml−1 v−1 s−1. 2.89 mg ml−1). M−1T−1T−1 assay showed that the antitumor activity of PTE-NPs on 4T1 breast cancer cells, MCF-7 breast cancer cells and Hela cervical cancer cells was significantly increased by 4, 6 and 8 times than that of free PTE, respectively. In vivo studies have shown that PTE-NPs has a certain dose dependence. When injected intraperitoneally, PTE-NPs showed a similar therapeutic effect as paclitaxel injection (TIR was 57.53% versus 57.23%) against 4T1 tumor-bearing mice. This should be due to the improved bioavailability of the drug caused by nano-drug delivery system (nano-DDS). These results indicate that PTE-NPs may be a clinically promising anti-tumor drug for breast cancer treatment.
Enhanced electrochemical performance of MnNi2O4/rGO nanocomposite as pseudocapacitor electrode material and methanol electro-oxidation catalyst
Authors: Askari Mohammad Bagher , Salarizadeh Parisa , Di Bartolomeo Antonio , Şen Fatih
Published: May 2021

Binary transition metal oxides with encouraging electrocatalyst properties have been suggested as electrode materials for supercapacitors and methanol oxidation. Hence, in this work, a binary mixed metal oxide based on nickel and manganese (MnNi2O4) and its hybrid with reduced graphene oxide were synthesized by a one-step hydrothermal method. After physical and morphological characterization, the potential of these nanostructures was investigated for use as supercapacitor electrodes and methanol electro-oxidation. The results of the electrochemical analysis showed a substantial effect of adding rGO to the MnNi2O4. The MnNi2O4/rGO hybrid electrode supercapacitor exhibited good stability of 93% after 2000 consecutive CV cycles and a specific capacitance of 575 F g−1at the current density of 0.5 A g−1. Furthermore, the application of this hybrid nanomaterial in the methanol electro-oxidation reaction (MOR) indicated its appropriate electrochemical efficiency and stability in methanol oxidation. Our results show that MnNi2O4/rGO can be considered as a promising electrode material for energy applications.
Enhanced exciton binding energy, Zeeman splitting and spin polarization in hybrid layered nanosheets comprised of (Cd, Mn)Se and nitrogen-doped graphene oxide: implication for semiconductor devices
Authors: Halder Oindrila , Mallik Gyanadeep , Suffczyński Jan , Pacuski Wojciech , Varadwaj Kumar Shidhartha K , Satpati Biswarup , Rath Satchidananda
Published: May 2021

The exciton properties of (Cd,Mn)Se-NrGO (nitrogen doped reduced graphene oxide) hybrid layered nanosheets have been studied in a magnetic field up to 10 T and compared to those of (Cd,Mn)Se nanosheets. The temperature dependent photoluminescence reveals the hybridization of inter-band exciton and intra-center Mn transition with enhancement of the binding energy of exciton-Mn hybridized state (80 meV with respect to 60 meV in (Cd,Mn)Se nanosheets) and increase of exciton—phonon coupling strength to 90 meV (with respect to 55 meV in (Cd,Mn)Se nanosheets). The circularly polarized magneto—photoluminescence at 2 K provides evidence for magnetic field induced exciton spin polarization and the realization of excitonic giant Zeeman splitting with g
eff as high as 165.4 ± 10.3, much larger than in the case of (Cd,Mn)Se nanosheets (63.9 ± 6.6), promising for implementation in spin active semiconductor devices.
SnO2 nanorods/graphene nanoplatelets nanocomposites: towards fast removal of malachite green and pathogen control
Authors: Arshad Aqsa , Nisar Tahira Qamar , Zulqurnain Muhammad , Niazi Robina Khan , Mansoor Qaisar
Published: May 2021

The world is facing alarming challenges of environmental pollution due to uncontrolled water contamination and multiple drug resistance of pathogens. However, these challenges can be addressed by using novel nanocomposites materials such as, SnO2/graphene nanopaletelets (GNPs) nanocomposites remarkably. In this work, we have prepared SnO2 nanorods and SnO2/GNPs nanocomposites (GS-I and GS-II) with size of 25 ± 6 nm in length and 4 ± 2 nm in diameter. The optical bandgap energies change from 3.14 eV to 2.80 eV in SnO2 and SnO2/GNPs nanocomposite. We found that SnO2/GNPs nanocomposite (GS-II) completely removes (99.11%) malachite green in 12 min, under UV light exposure, while under same conditions, SnO2 nanorods removes only 37% dye. Moreover, visible light exposure resulted in 99.01% removal of malachite green in 15 min by GSII as compared to 24.7% removal by SnO2. In addition, GS-II nanocomposite inhibits 79.57% and 78.51% growth of P. aeruginosa and S. aureus respectively. A synchronized contribution of SnO2 and GNPs makes SnO2/GNPs nanocomposites (GS-II) an innovative multifunctional material for simultaneous fast and complete removal of malachite green and inhibition of drug resistant pathogens.
Ion-temperature-gradient stability near the magnetic axis of quasisymmetric stellarators
Authors: Jorge R , Landreman M
Published: May 2021

The stability of the ion-temperature gradient mode in quasisymmetric stellarators is assessed. This is performed using a set of analytical estimates together with linear gyrokinetic simulations. The peak growth rates, their corresponding real frequencies and wave-vectors are identified. A comparison is made between a first-order near-axis expansion model and eleven realistic designs obtained using numerical optimization methods. It is found that while the near-axis expansion is able to replicate the growth rates, real frequencies and perpendicular wave-vector at the inner core (both using simplified dispersion relations and first-principle gyrokinetic simulations), it leads to an overestimation of the growth rate at larger radii. An approximate analytic solution of the ITG dispersion relation for the non-resonant limit suggests growth rates could be systematically higher in quasi-axisymmetric (QA) configurations compared to quasi-helically (QH) symmetric ones. However except for very close to the axis, linear gyrokinetic simulations do not show systematic differences between QA and QH configurations.
Modeling dislocation-related reverse bias leakage in GaN p–n diodes
Authors: Qwah K S , Robertson C A , Wu Y-R , Speck J S
Published: May 2021

Finite element analysis software was used to model and visualize two p-n junction models: one with a single threading dislocation (TD) and a control without one. TDs are modeled as a Gaussian distribution of trap states with a full width at half maximum value of 5 nm localized around the

r
=
0

line in a cylindrical coordination such that the linear trap state density was 1 trap c−1-translation; this model allows the cylindrical symmetry of the c-plane GaN crystal orientation to be used to avoid more computationally intensive 3D models. In this work, a vertical p–n diode with typical doping characteristics and an equivalent threading dislocation density of

10
8

 c

m

−
2

was modeled in reverse bias. Our simulations show that the dislocation-mediated leakage mechanism for reverse bias leakage in GaN p–n diodes is the generation of electron–hole pairs via a trap-assisted tunneling mechanism whereby electrons from the valence band use the intermediate trap state to traverse the band gap. This mechanism results in electron–hole pairs that are swept out of the junction by the reverse bias electric field. This behavior results in a measurable leakage current within the model with behavior consistent with experimental values.
Prospects for single-molecule electrostatic detection in molecular motor gliding motility assays
Authors: Miranda M Sanchez , Lyttleton R , Siu P H , Diez S , Linke H , Micolich A P
Published: May 2021

Molecular motor gliding motility assays based on myosin/actin or kinesin/microtubules are of interest for nanotechnology applications ranging from cargo-trafficking in lab-on-a-chip devices to novel biocomputation strategies. Prototype systems are typically monitored by expensive and bulky fluorescence microscopy systems. The development of integrated, direct electric detection of single filaments would strongly benefit applications and scale-up. We present estimates for the viability of such a detector by calculating the electrostatic potential change generated at a carbon nanotube transistor by a motile actin filament or microtubule under realistic gliding assay conditions. We combine this with detection limits based on previous state-of-the-art experiments using carbon nanotube transistors to detect catalysis by a bound lysozyme molecule and melting of a bound short-strand DNA molecule. Our results show that detection should be possible for both actin and microtubules using existing low ionic strength buffers given good device design, e.g., by raising the transistor slightly above the guiding channel floor. We perform studies as a function of buffer ionic strength, height of the transistor above the guiding channel floor, presence/absence of the casein surface passivation layer for microtubule assays and the linear charge density of the actin filaments/microtubules. We show that detection of microtubules is a more likely prospect given their smaller height of travel above the surface, higher negative charge density and the casein passivation, and may possibly be achieved with the nanoscale transistor sitting directly on the guiding channel floor.
Moving frames and compatibility conditions for three-dimensional director fields
Authors: da Silva Luiz C B , Efrati Efi
Published: May 2021

The geometry and topology of the region in which a director field is embedded impose limitations on the kind of supported orientational order. These limitations manifest as compatibility conditions that relate the quantities describing the director field to the geometry of the embedding space. For example, in two dimensions the splay and bend fields suffice to determine a director uniquely (up to rigid motions) and must comply with one relation linear in the Gaussian curvature of the embedding manifold. In 3D there are additional local fields describing the director, i.e. fields available to a local observer residing within the material, and a number of distinct ways to yield geometric frustration. So far it was unknown how many such local fields are required to uniquely describe a 3D director field, nor what are the compatibility relations they must satisfy. In this work, we address these questions directly. We employ the method of moving frames to show that a director field is fully determined by five local fields. These fields are shown to be related to each other and to the curvature of the embedding space through six differential relations. As an application of our method, we characterize all uniform distortion director fields, i.e., directors for which all the local characterizing fields are constant in space, in manifolds of constant curvature. The classification of such phases has been recently provided for directors in Euclidean space, where the textures correspond to foliations of space by parallel congruent helices. For non-vanishing curvature, we show that the pure twist phase is the only solution in positively curved space, while in the hyperbolic space uniform distortion fields correspond to foliations of space by (non-necessarily parallel) congruent helices. Further analysis of the obtained compatibility fields is expected to allow to also construct new non-uniform director fields.
Investigating the role of diamagnetic Cd2+ ions on the structural, optical, and magnetic properties of YIG
Authors: Assi B , Bitar Z , Malaeb W , Sayed Hassan R , Yaacoub N , Awad R
Published: May 2021

In this study, Y3-xCdxFe5O12 (0.0 ≤ × ≤0.2) powders were synthesized via the co-precipitation method at calcination temperature 1100 °C. The phase formation of YIG was confirmed from X-ray powder diffraction (XRD) and Fourier Transform Infrared (FTIR) technique. The change of the band-gap energy, determined from the analysis of UV-visible spectroscopy, with the particle size was in agreement with the quantum confinement effect for x between 0.02 and 0.2. The magnetization study showed a non-monotonic change in the saturation magnetization and the coercivity with the increase of Cd2+ content. This behavior is an indication of both effect of particle size and the concentration of the doped Cadmium. The Mӧssbauer spectroscopy analysis confirmed the existence of Fe3+ in both octahedral and tetrahedral sites and the non-existence of Fe2+.