bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel polymerization of nitrogen in zinc nitrides at high pressures
Authors: Du Huifang , Guo Wei 
Published: March 2022

Abstract
Nitrogen-rich compounds containing polynitrogen are attractive candidates for high-energy-density materials. In this work, using first-principles calculations and a particle swarm optimization structural search method, four novel nitrogen-rich structures are predicted at high pressures, i.e., two ZnN3 phases with the same space group P1 (low-pressure phase LP-ZnN3 and high-pressure phase HP-ZnN3), Cmm2-ZnN5 and Pcc2-ZnN6, the energy density are estimated to be 1.41 kJ g−1, 1.88 kJ g−1, 4.07 kJ g−1, and 2.60 kJ g−1, respectively. LP-ZnN3 (54–72 GPa) and HP-ZnN3 (above 72 GPa) have the lowest enthalpies in all known ZnN3 phases, and the N6 chains in LP-ZnN3 polymerize into infinite nitrogen chains in HP-ZnN3 at 72 GPa, showing a narrow-band-gap-semiconductor to metallic phase transition. Interestingly, P1-ZnN3 has a superconducting transition temperature of 6.2 K at 50 GPa and 16.3 K at 100 GPa. In Cmm2-ZnN5 and Pcc2-ZnN6, nitrogen atoms polymerize into three-dimensional network structures and network layers under high pressures. Those predicted structures may enrich the phase diagram of high-pressure zinc nitrides, and provide clues for synthesis and exploration of novel stable polymeric nitrogen.
Mechanical characterization of reinforced vertically-aligned carbon nanotube array synthesized by shock-induced partial phase transition: insight from molecular dynamics simulations
Authors: Edalatmanesh Alireza , Mahnama Maryam , Feghhi Fatemeh , Mashhadi Mahmoud Mosavi 
Published: March 2022

Abstract
Despite intriguing mechanical properties of carbon nanotubes (CNTs), vertically-aligned carbon nanotube (VACNT) array does not possess a high strength against compression along the CNT axis and also the loadings perpendicular to the CNT axis. Here in this study, shock compression is introduced as a means for partial phase transition (PPT) in the VACNT array to reinforce the structure against the mentioned loadings. Molecular dynamics simulations are exploited to investigate the synthesis of a novel nanostructure from a VACNT array with 10 nm long (5, 5) CNTs. Employing Hugoniostat method, shockwave pressures of 6.6 GPa and 55 GPa are extracted from Hugoniot curves as the instability limit and the PPT point, respectively. Coordination analysis reveals the nucleation of carbon atoms in sp3 hybridization while preserving the dominant nature of CNT due to the high percent of sp2 hybridization. Recovery of the shocked samples yields the final structure to be tested for mechanical characteristics. Tensile and compression tests on the samples reveal that for the shockwave pressures below the PPT point, an increase of the shock strength leads to higher compliance in the VACNT array. However, beyond the PPT point the novel nanostructure shows an extraordinary strong behavior against loading along all directions.
Peak-tracking scanning capacitance force microscopy with multibias modulation technique
Authors: Fukuzawa Ryota , Takahashi Takuji 
Published: March 2022

Abstract
Scanning capacitance force microscopy (SCFM) is a good method for capacitance measurements using electrostatic force detection. However, to obtain an entire capacitance–voltage (C–V) curve by SCFM, a sweep of a direct current (DC) bias voltage is required at a certain fixed point on a sample surface during scan suspension, and thus the measurements become very time-consuming when we want to observe some types of image related with C–V characteristics. In this paper, we propose peak-tracking scanning capacitance force microscopy (PTSCFM) for the purpose of extracting the main feature of the C–V curve without DC voltage sweep. In PT-SCFM, alternating current voltages at three different angular frequencies, ω
1, ω
2, and

ω

m

, are applied together with DC voltage,

V

D
C

, to generate an electrostatic force, and high-order components at the angular frequencies of

ω
2

−
2

ω
1

and

ω
2

−
2

ω
1

−

ω

m

, which represent a voltage derivative of a capacitance (

∂
C

/

∂
V

) and a second-order derivative of the capacitance (

∂
2

C

/

∂

V
2

), respectively, are extracted from the electrostatic force. Then, a DC voltage,

V

p

, giving the peak of

∂
C

/

∂
V

is determined from

V

D
C

to be adjusted to nullify the

ω
2

−
2

ω
1

−

ω

m

component using a feedback controller. From the obtained values of

V

p

and

∂
C

/

∂
V

at

V

p

, the C–V curve can be outlined. In PT-SCFM, the distributions of those values are simultaneously imaged together with a topography without

V

D
C

sweep, and when we operate PT-SCFM under various modulation frequency conditions, analyses similar to those based on the frequency dependence of the C–V property are realized. We have applied the PT-SCFM to a microcrystalline

C
u
(
I
n
,
G
a
)
S

e
2

material to discuss the effects of surface depletion and deep-level states, from which the validity of PT-SCFM has been examined.
Protein adsorption onto nanomaterials engineered for theranostic applications
Authors: Nienhaus Karin , Xue Yumeng , Shang Li , Nienhaus Gerd Ulrich 
Published: March 2022

Abstract
The key role of biomolecule adsorption onto engineered nanomaterials for therapeutic and diagnostic purposes has been well recognized by the nanobiotechnology community, and our mechanistic understanding of nano-bio interactions has greatly advanced over the past decades. Attention has recently shifted to gaining active control of nano-bio interactions, so as to enhance the efficacy of nanomaterials in biomedical applications. In this review, we summarize progress in this field and outline directions for future development. First, we briefly review fundamental knowledge about the intricate interactions between proteins and nanomaterials, as unraveled by a large number of mechanistic studies. Then, we give a systematic overview of the ways that protein-nanomaterial interactions have been exploited in biomedical applications, including the control of protein adsorption for enhancing the targeting efficiency of nanomedicines, the design of specific protein adsorption layers on the surfaces of nanomaterials for use as drug carriers, and the development of novel nanoparticle array-based sensors based on nano-bio interactions. We will focus on particularly relevant and recent examples within these areas. Finally, we conclude this topical review with an outlook on future developments in this fascinating research field.
Switching-behavior improvement in HfO2/ZnO bilayer memory devices by tailoring of interfacial and microstructural characteristics
Authors: Zhang Wei , Lei Jianzhang , Dai Yixian , Zhang Xuehua , Kang Limin , Peng Bowen , Hu Fangren 
Published: March 2022

Abstract
We investigated the effect of top contact interface and microstructural characteristics of the insulating layers on resistive switching behaviors by fabricating and characterizing the HfO2/ZnO bilayer heterostructures. Different thickness of ZnO underlying layer and different deposition temperatures of the upper HfO2 layer were designed to analyze the intrinsic contribution of the crystalline microstructure of the insulating bilayer. Pt and Ti top electrodes were used to demonstrate the extrinsic contribution of the interface configuration. It was observed that all devices show bipolar RS characteristics. Unlike the device composed of Pt/HfO2/ZnO/Pt that exhibit an abrupt switching, a gradually continuous switching in the reset process was identified in the device composed of Ti/HfO2/ZnO/Pt. Interfacial charge migration process/characteristic plays a key role in the RS process as well as its conduction mechanism. The RS performance of the former is significantly better than that of the latter, including much lower reset voltage, two orders of magnitude larger OFF/ON ratio and HRS resistance. In addition, as compared to the intrinsic contribution arising from the microstructure of the HfO2/ZnO bilayer to the RS performances and current transport mechanism, the extrinsic effect contributed from the electrode characteristics (and its interface) is dominant.
Boron nitride nanosheets supported highly homogeneous bimetallic AuPd alloy nanoparticles catalyst for hydrogen production from formic acid
Authors: Shaybanizadeh Shahram , Najafi Chermahini Alireza , Luque Rafael 
Published: March 2022

Abstract
Formic acid (FA) has been recently regarded as a safe and stable source of hydrogen (H2). Selective and efficient dehydrogenation of FA by an effective catalyst under mild conditions is still a challenge. So, different molar ratios of bimetallic Pd–Au alloy nanoparticles were effectively stabilized and uniformly distributed on boron nitride nanosheets (BNSSs) surface via the precipitation process. Obtained catalysts were employed in FA decomposition for H2 production. Pd–Au@BNNS containing 3% Au and 5% Pd (Au.03Pd.05@BNNS) exhibited high activity and 100% H2 selectivity for H2 production from FA at 50 °C. In order to optimize the reaction conditions, various factors including, time, temperature, solvent, base type, and amount of catalyst, were examined.
Platinum nanoparticle sensitized plasmonic-enhanced broad spectral photodetection in large area vertical-aligned MoS2 flakes
Authors: Wadhwa Riya , Ghosh Anupam , Kumar Deepu , Kumar Pradeep , Kumar Mukesh 
Published: March 2022

Abstract
2D MoS2 holds immense potential for electronic and optoelectronic applications due to its unique characteristics. However, the atomic-scale thickness of MoS2 hinders the optical absorbance, thereby limiting its photodetection capability. Vertically-aligned MoS2 (VA-MoS2) has an advantage of strong optical absorption and quick intra-layer transport, offering high speed operation. The coupling of plasmonic metal nanostructure with MoS2 can further enhance the light–matter interaction. Pt/Pd (as opposed to Ag/Au) are more promising to design next-generation nano-plasmonic devices due to their intense interband activity over a broad spectral range. Herein, we report Pt nanoparticle (NPs) enhanced broadband photoresponse in VA-MoS2. The optical absorbance of MoS2 is enhanced after the integration of Pt NPs, with a four-fold enhancement in photocurrent. The formation of Schottky junction at Pt-MoS2 interface inhibits electron transmission, suppressing the dark current and substantially reducing NEP. The plasmonic-enabled photodetector shows enhanced responsivity (432 A W−1, 800 nm) and detectivity (1.85 × 1014 Jones, 5 V) with a low response time (87 ms/84 ms), attributed to faster carrier transport. Additionally, a theoretical approach is adopted to calculate wavelength-dependent responsivity, which matches well with experimental results. These findings offer a facile approach to modulate the performance of next-generation optoelectronic devices for practical applications.
Attosecond spectroscopy for the investigation of ultrafast dynamics in atomic, molecular and solid-state physics
Authors: Borrego-Varillas Rocío , Lucchini Matteo , Nisoli Mauro 
Published: March 2022

Abstract
Since the first demonstration of the generation of attosecond pulses (1 as = 10−18 s) in the extreme-ultraviolet spectral region, several measurement techniques have been introduced, at the beginning for the temporal characterization of the pulses, and immediately after for the investigation of electronic and nuclear ultrafast dynamics in atoms, molecules and solids with unprecedented temporal resolution. The attosecond spectroscopic tools established in the last two decades, together with the development of sophisticated theoretical methods for the interpretation of the experimental outcomes, allowed to unravel and investigate physical processes never observed before, such as the delay in photoemission from atoms and solids, the motion of electrons in molecules after prompt ionization which precede any notable nuclear motion, the temporal evolution of the tunneling process in dielectrics, and many others. This review focused on applications of attosecond techniques to the investigation of ultrafast processes in atoms, molecules and solids. Thanks to the introduction and ongoing developments of new spectroscopic techniques, the attosecond science is rapidly moving towards the investigation, understanding and control of coupled electron–nuclear dynamics in increasingly complex systems, with ever more accurate and complete investigation techniques. Here we will review the most common techniques presenting the latest results in atoms, molecules and solids.
Wave–particle complementarity: detecting violation of local realism with photon-number resolving weak-field homodyne measurements
Authors: Das Tamoghna , Karczewski Marcin , Mandarino Antonio , Markiewicz Marcin , Woloncewicz Bianka , Żukowski Marek 
Published: March 2022

Abstract
Nowadays photon-number resolving weak-field homodyne measurements allow realization of emblematic gedankenexperiments revealing correlations of optical fields. This covers experiments on (a) excitation of a pair of spatial modes by a single photon, and (b) two spatial modes in a weakly squeezed vacuum state, involving constant local oscillator strengths. Proving Bell nonclassicality of such correlations demands measurements of complementary observables. We show that typical arrangement of weak-field homodyne detection with measurement settings defined by phases of local oscillators of constant strength does not provide enough complementarity for confirming Bell nonclassicality. In the case of experiment (a) we provide an exact local hidden variable model restoring all quantum probabilities, whereas in the case of experiment (b) we show that the claims of its nonclassicality are unfounded. A full complementarity of wave aspects vs particle (number) can be achieved in a measurement situation in which respectively the local oscillators are on or off. This is shown to lead to an operational scenario, in the case of both experiments (a) and (b), which reveals indisputable violations of local realism. Such schemes may find possible applications in device-independent quantum protocols.
Few-femtosecond resolved imaging of laser-driven nanoplasma expansion
Authors: Peltz C , Powell J A , Rupp P , Summers A , Gorkhover T , Gallei M , Halfpap I , Antonsson E , Langer B , Trallero-Herrero C , Graf C , Ray D , Liu Q , Osipov T , Bucher M , Ferguson K , Möller S , Zherebtsov S , Rolles D , Rühl E , Coslovich G , Coffee R N , Bostedt C , Rudenko A , Kling M F , Fennel T 
Published: March 2022

Abstract
The free expansion of a planar plasma surface is a fundamental non-equilibrium process relevant for various fields but as-yet experimentally still difficult to capture. The significance of the associated spatiotemporal plasma motion ranges from astrophysics and controlled fusion to laser machining, surface high-harmonic generation, plasma mirrors, and laser-driven particle acceleration. Here, we show that x-ray coherent diffractive imaging can surpass existing approaches and enables the quantitative real-time analysis of the sudden free expansion of laser-heated nanoplasmas. For laser-ionized SiO2 nanospheres, we resolve the formation of the emerging nearly self-similar plasma profile evolution and expose the so far inaccessible shell-wise expansion dynamics including the associated startup delay and rarefaction front velocity. Our results establish time-resolved diffractive imaging as an accurate quantitative diagnostic platform for tracing and characterizing plasma expansion and indicate the possibility to resolve various laser-driven processes including shock formation and wave-breaking phenomena with unprecedented resolution.
Strong ensemble nonequivalence in systems with local constraints
Authors: Zhang Qi , Garlaschelli Diego 
Published: March 2022

Abstract
The asymptotic equivalence of canonical and microcanonical ensembles is a central concept in statistical physics, with important consequences for both theoretical research and practical applications. However, this property breaks down under certain circumstances. The most studied violation of ensemble equivalence requires phase transitions, in which case it has a ‘restricted’ (i.e. confined to a certain region in parameter space) but ‘strong’ (i.e. characterized by a difference between the entropies of the two ensembles that is of the same order as the entropies themselves) form. However, recent research on networks has shown that the presence of an extensive number of local constraints can lead to ensemble nonequivalence (EN) even in the absence of phase transitions. This occurs in a ‘weak’ (i.e. leading to a subleading entropy difference) but remarkably ‘unrestricted’ (i.e. valid in the entire parameter space) form. Here we look for more general manifestations of EN in arbitrary ensembles of matrices with given margins. These models have widespread applications in the study of spatially heterogeneous and/or temporally nonstationary systems, with consequences for the analysis of multivariate financial and neural time-series, multi-platform social activity, gene expression profiles and other big data. We confirm that EN appears in ‘unrestricted’ form throughout the entire parameter space due to the extensivity of local constraints. Surprisingly, at the same time it can also exhibit the ‘strong’ form. This novel, simultaneously ‘strong and unrestricted’ form of nonequivalence is very robust and imposes a principled choice of the ensemble. We calculate the proper mathematical quantities to be used in real-world applications.
Effect of vanadium doping on the structural and optical characteristics of nano ZnCdS
Authors: Heiba Zein K , Mohamed Mohamed Bakr , Badawi Ali 
Published: March 2022

Abstract
Nano Zn0.75-xCd0.25VxS (0 ≤ x ≤ 0.2, step 0.05) samples were formed by the molten salt solid state reaction method at low temperature. Synchrotron x-ray diffraction phase identification revealed biphasic ZnS structure for all samples, cubic zinc blende and hexagonal wurtzite. Rietveld analysis was applied to determine the effect of V-doping on the percentage of each phase and their structural and microstructural parameters. The existence of V ions in the Zn0.75Cd0.25S (ZnCdS) lattice is confirmed by Fourier-transform infrared spectroscopy (FTIR) technique. Utilizing the UV–vis diffuse reflectance spectroscopy, the effect of V-doping on the absorption, reflectance, refractive index, extinction coefficient and electric properties of ZnCdS were studied in detail. The optical bandgap (Eg) significantly decreased from 2.82 eV for zero V-doping to 2.55 eV for x = 0.2. Also, the refractive index decreased sharply in the wavelength region 450–900 nm. ZnCdS sample has anomalous dispersion behavior while the doped samples have anomalous and normal dispersion features. The photoluminescence intensity and emitted colors in the UV and visible regions were affected by the amount of doping.
PicSat’s Enduring Legacy. Probing the Flight of a Small Astronomical Satellite
Authors: Menegaldo Cauê G. , de O. Fialho Fábio , Janot-Pacheco Eduardo , Pait Felipe M. , Lapeyrère Vincent 
Published: March 2022

Abstract
Observation of planetary transits and other cutting-edge scientific missions can take advantage of affordable nanosatellites to probe interesting stellar targets. PicSat, a CubeSat dedicated to observing the Beta Pictoris star system, was designed to provide high-precision star pointing, a critical requirement for planetary transit detection. PicSat’s Attitude Determination and Control System, responsible for delivering high-accuracy spacecraft pointing, requires dedicated development based on dynamic simulators. This paper presents a dynamic attitude and orbit propagation simulator for CubeSats in low Earth orbit, as well as for its de-tumbling mode. Validation has been performed through PicSat’s in-flight data. High-precision dynamic models have been obtained for both attitude and orbit. Such models are well suited to the different mission phases, from spacecraft design to data exploitation. It is, therefore, a crucial tool to minimize the chance of failure of both the platform and the payload, especially in satellites such as PicSat, whose pointing depends on both. PicSat left an enduring legacy: its platform data allow us to obtain flight models that will be valuable for future missions.
First uncertainty evaluation of the cesium fountain primary frequency standard NMIJ-F2
Authors: Takamizawa Akifumi , Yanagimachi Shinya , Hagimoto Ken 
Published: March 2022

Abstract
We report the first uncertainty evaluation of NMIJ-F2, the second atomic fountain primary frequency standard at the National Metrology Institute of Japan. To improve the frequency stability, we increase the number of detected atoms to 9 × 105 using high-power cooling laser beams for vapor-loaded optical molasses and optical pumping into the Zeeman sublevel m
F = 0. We also employ an ultra-stable cryogenic sapphire oscillator as a local oscillator to prevent the degradation of frequency stability due to the Dick effect. After correcting the collisional frequency shift by alternating atom densities, the frequency stability typically reaches 2.5 × 10−13(τ/s)−1/2. Its value is 1.9 × 10−16 after 20 days of measurement. Type B uncertainty is typically evaluated at 4.7 × 10−16; the largest contribution is from a distributed cavity phase shift, followed by a microwave leakage shift. In long-term comparison, the frequency of NMIJ-F2 is found to be consistent with that of the other primary and secondary frequency standards within the uncertainty.
Diffusion-mediated absorption by partially-reactive targets: Brownian functionals and generalized propagators
Authors: Bressloff Paul C 
Published: March 2022

Abstract
Many processes in cell biology involve diffusion in a domain Ω that contains a target

U

whose boundary

∂
U

is a chemically reactive surface. Such a target could represent a single reactive molecule, an intracellular compartment or a whole cell. Recently, a probabilistic framework for studying diffusion-mediated surface reactions has been developed that considers the joint probability density or generalized propagator for particle position and the so-called boundary local time. The latter characterizes the amount of time that a Brownian particle spends in the neighborhood of a point on a totally reflecting boundary. The effects of surface reactions are then incorporated via an appropriate stopping condition for the boundary local time. In this paper we extend the theory of diffusion-mediated absorption to cases where the whole interior target domain

U

acts as a partial absorber rather than the target boundary

∂
U

. Now the particle can freely enter and exit

U

, and is only able to react (be absorbed) within

U

. The appropriate Brownian functional is then the occupation time (accumulated time that the particle spends within

U

) rather than the boundary local time. We show that both cases can be considered within a unified framework, which consists of a boundary value problem (BVP) for the propagator of the corresponding Brownian functional and an associated stopping condition. We illustrate the theory by calculating the mean first passage time (MFPT) for a spherical target

U

located at the center of a spherical domain Ω. This is achieved by solving the propagator BVP directly, rather than using spectral methods. We find that if the first moment of the stopping time density is infinite, then the MFPT is also infinite, that is, the spherical target is not sufficiently absorbing.