bluuebunny/crossref_metadata_2025_split huggingface dataset:
Etch-less microfabrication of structured TiO2 implant coatings on bulk titanium grade 23 by direct lithographic anodic oxidation
Authors: Doll P W , Ahrens R , Guber A E 
Published: January 2021

Abstract
Within this work, we demonstrate a method for the etch-less, additive microfabrication of TiO2 thin film layers on top of the medical implant material titanium grade 23. A combination of common UV-lithographic microfabrication and a subsequent anodic oxidation process allows the direct additive fabrication of microstructured oxide layers on top of the bulk base material without the use of any additional preparation or etching step. Titanium grade 23 samples were firstly prepared by grinding and polishing to achieve an adequate surface finish for UV lithography. Photoresist was applied to the samples and lithographically structured using line patterns with lateral sizes ranging from 1.5 up to 50 µm. The samples were then anodically oxidized within a H2SO4 containing electrolyte and the resist patterns could successfully be copied into the resulting oxide layers. The presented method allows cost-effective and fast microfabrication of structured oxide thin film layers while protecting the underlying bulk material from hazardous etching media, often containing hydrofluoric acid, enabling novel implant coating designs and fabrication concepts for future works.
Enhancing discrete-modulated continuous-variable measurement-device-independent quantum key distribution via quantum catalysis
Authors: Ye Wei , Guo Ying , Zhang Huan , Zhong Hai , Mao Yun , Hu Liyun 
Published: January 2021

Abstract
Discrete modulation can make up for the shortage of transmission distance in measurement-device-independent continuous-variable quantum key distribution (MDI-CVQKD), providing a unique advantage against all side-channel attacks but also creating a challenge for further performance improvement. Here we suggest a quantum catalysis (QC) approach for enhancing the performance of the discrete-modulated (DM) MDI-CVQKD in terms of the achievable secret key rate and lengthening the maximal transmission distance. The numerical simulation results show that the QC-based MDI-CVQKD with discrete modulation, involving a zero-photon catalysis (ZPC) operation, can not only obtain a higher secret key rate than the original DM protocol, but also contribute to a reasonable increase of the corresponding optimal variance. As for the extreme asymmetric and symmetric cases, the secret key rate and maximal transmission distance of the ZPC-involved DM MDI-CVQKD system can be further improved under the same parameters. This approach enables the system to tolerate lower reconciliation efficiency, which may provide excellent potential for practical implementations with state-of-art technology.
A hybrid modeling framework for the investigation of surface roughening of polymers during oxygen plasma etching
Authors: Memos George , Lidorikis Elefterios , Gogolides Evangelos , Kokkoris George 
Published: January 2021

Abstract
Oxygen and oxygen-containing plasmas offer great potential for the surface functionalization of polymeric substrates: thermal reactive neutral species are combined with high energy ions to alter both the micro/nanomorphology and composition of polymeric surfaces in a dry process. Although plasma processing is an attractive option for polymer surface modification, plasma–surface interactions are complex and the process design is usually based on a trial-and-error procedure. Toward a comprehensive process design, a hybrid modeling framework, addressing both effects of plasmas on polymeric surfaces, is developed and applied to an investigation of the oxygen-plasma-induced surface roughening of poly(methyl methacrylate). A kinetic Monte Carlo surface model, considering the synergy of neutral species and ions, is used for the calculation of the local etching rate. The novel element of the model is that it takes into account the surface morphology through the calculation of the trajectories of the species joining the surface reactions. The local etching rate is utilized by a profile evolution module based on the level set method to predict the surface roughness evolution. A method for tracking the local variables of the evolving surface profile (e.g. surface coverage), treating a fundamental weakness of the level set method, is proposed and used to effectively reduce the computational time. The results of the framework are validated by comparison to a theoretical model. The prediction of roughness evolution is consistent with measurements vs time and at different operating conditions. The potential of the framework to additionally handle the chemical composition (oxidation) of the surface is demonstrated, enabling the study of the wetting behavior of plasma-etched polymeric surfaces.
Analysis of the physical and photoelectrochemical properties of c-Si(p)/a-SiC:H(p) photocathodes for solar water splitting
Authors: Carmen Mejia María del , Sánchez Luis Francisco , Kurniawan Mario , Eggert Lara , Tejada Alvaro , Camargo Magali , Grieseler Rolf , Rumiche Francisco , Díaz Isabel , Bund Andreas , Guerra Jorge Andrés 
Published: January 2021

Abstract
The photoelectrochemical (PEC) properties of sputtered aluminum doped hydrogenated amorphous silicon carbide thin films grown on p-type crystalline silicon substrates were investigated in 1 M

H

2

S
O

4

solution under chopped light illumination. Optical and structural properties of the top absorber layer were systematically assessed after post-deposition isochronical annealing treatments. Samples exhibited a noticeable improvement of the opto-electronic properties after thermal treatments. In addition, an abrupt enhancement of the photocurrent was observed reaching a saturation value of 17 mA cm−2 at −1.75 V vs. Ag/AgCl (3.5 M KCl). In this research we propose that this enhancement effect is associated to a charge transfer kinetic mechanism influenced by surface states and the p-type substrate. The latter most likely due to the space charge region extending beyond the absorber layer reaching the substrate. Current density-potential and electrochemical impedance spectroscopy measurements in dark revealed a reduction of the

S
i
O

2

native layer at cathodic potentials higher than −1 V vs. Ag/AgCl (3.5 M KCl), which contributes to the high charge transfer kinetic of the system. We believe that these results will contribute to understand the substrate influence in the PEC performance of top absorber layers in multilayer structures for solar water splitting.
Sub-picosecond exchange–relaxation in the compensated ferrimagnet Mn2Ru
x
Ga
Authors: Bonfiglio G , Rode K , Atcheson G Y P , Stamenov P , Coey J M D , Kimel A V , Rasing Th , Kirilyuk A 
Published: January 2021

Abstract
We study the demagnetization dynamics of the fully compensated half-metallic ferrimagnet Mn2Ru
x
Ga. While the two antiferromagnetically coupled sublattices are both composed of manganese, they exhibit different temperature dependencies due to their differing local environments. The sublattice magnetization dynamics triggered by femtosecond laser pulses are studied to reveal the roles played by the spin and intersublattice exchange. We find a two-step demagnetization process, similar to the well-established case of Gd(FeCo)3, where on a 5 ps timescale the two Mn-sublattices seem to have different demagnetization rates. The behaviour is analysed using a four-temperature model, assigning different temperatures to the two manganese spin baths. Even in this strongly exchange-coupled system, the two spin reservoirs have considerably different behaviour. The half-metallic nature and strong exchange coupling of Mn2Ru
x
Ga lead to spin angular momentum conservation at much shorter time scales than found for Gd(FeCo)3 which suggests that low-power, sub-picosecond switching of the net moment of Mn2Ru
x
Ga is possible.
Spin induced exchange bias and lattice modulation in Nd1−x
Eu
x
CrO3
Authors: Gupta Pragya , Pal D 
Published: January 2021

Abstract
We report the evolution of coupled phonons and exchange bias (EB) in perovskite-type Nd1−x
Eu
x
CrO3 (x = 0.0, 0.05, and 0.10) samples by means of temperature-dependent Raman spectroscopy and dc magnetization measurements. We observed a non-monotonic behavior of the EB field around the temperature T
*, which lies between the antiferromagnetic ordering temperature (T
N) and spin-reorientation transition temperature (T
SR). The temperature dependence of phonon modes related to antistretching and bending of CrO6 octahedra and Nd3+/Eu3+ ion vibration below T
N confirms the strong spin–phonon coupling. The T
* found from the non-monotonicity of the EB is imprinted with the additional anomaly observed in the low-temperature spin–phonon behavior. The phonon modes and phonon anomaly are also verified using the density functional theory-based calculations.
Exchange interactions in ɛ-Fe2O3: GGA + U calculations
Authors: Knížek K , Novák P , Jirák Z 
Published: January 2021

Abstract
We have studied the origin of magnetic interaction in ɛ-Fe2O3 by ab-initio electronic structure calculations. The exchange integrals of the Heisenberg Hamiltonian have been calculated using the methods based on the density functional theory (DFT) employing generalized gradient approximation (GGA) with orbital dependent potential extension for 3d electrons of Fe (GGA + U method). The calculations confirm the ground antiferromagnetic (AFM) state with two Fe3+ sublattices oriented up (Fe2 and Fe3) and two Fe3+ sublattices oriented down (Fe1 and Fe4). The calculated exchange integrals, including also the intra-sublattice ones, are all of AFM type. Their strength weighted by the number of neighbors is larger between the Fe sublattices with opposite spins than between the sublattices with equal spin directions. The notable exception is a strong exchange integral between the neighboring tetrahedrally-coordinated sites within the Fe4 sublattice, which effectively decreases the molecular field imposed on Fe4 sites by neighboring sites of other sublattices, namely the antiparallelly oriented Fe2 and Fe3. For this reason, the ordered magnetic moment of Fe4 exhibits the fastest decrease with increasing temperature among the sublattices, leading to an uncompensated AFM arrangement in ɛ-Fe2O3. Considering the competition of the inter- and intra-sublattice exchange integrals and applying symmetry arguments, we infer that the collinear AFM ground state of ɛ-Fe2O3 is prone to an intrinsic canting within the sublattices, retaining at the same time the magnetic group symmetry Pna′21′.
Flow status identification based on multiple slow feature analysis of gas–liquid two-phase flow in horizontal pipes
Authors: Dong Feng , Li Linghan , Zhang Shumei 
Published: January 2021

Abstract
A gas–liquid two-phase flow is a highly complex and random process with complicated and variable flow statuses. The status identification of two-phase flows focuses on the situation of flow processes over specific time periods, as reflected by flow regimes, phase holdup, flow velocity, and other parameters. Aiming to discover how to obtain flow status information and identify the flow statuses of gas–liquid two-phase flows in horizontal pipes, a meticulous identification method based on multiple slow feature analysis combined with Bayesian inference is proposed, with concurrent monitoring of steady states and process dynamics. In this method, representational models for different typical flow regimes are established to describe both the steady states and temporal distributions. On this basis, by monitoring statistics and developing a Bayesian inference-based index, the current flow status can be identified online. Besides status identification, process dynamics are monitored to detect the dynamic characteristics of the current process with meaningful physical interpretation and deep process understanding. The application of this method to typical flow regimes and the status of transitions from bubble flow to slug flow demonstrates the feasibility and efficacy of the proposed method.
Error analysis and reflection correction for radiation temperature measurements at high background temperatures
Authors: Gao Shan , Zhao Chunhui , Chen Liwei , Jiang Jing , Yu Peifeng , Zhang Zezhan , Wang Chao 
Published: January 2021

Abstract
Advances in science and technology have increased the demand for greater temperature measurement accuracy. Radiation thermometry is a mature technology that is applicable to various industrial fields. In special environments (e.g. a high ambient temperature), background radiation reflected by the target surface is superimposed with the radiation from the target itself, which affects the measured radiation temperature. In this study, different radiation thermometry methods were evaluated. The errors of single-spectral, colorimetric, and multispectral temperature measurements of targets in a high-temperature environment have been discussed. Based on this, we propose a multi-wavelength temperature measurement method with reflection correction to reduce the impact of high-temperature environment. Experiments show that this method can reduce the uncertainty in the multispectral temperature measurement from 4.16% to 0.26% under the experimental conditions.
An encoder signal-based approach for low-speed planetary gearbox fault diagnosis
Authors: Ou Shudong , Zhao Ming , Zhou Tao , Guo Dong 
Published: January 2021

Abstract
Low-speed rotating machines are extensively used in heavy industry. Among those, the planetary gearbox is a pivotal component with a high power–weight ratio and large loadbearing capacity, which inevitably fail due to the tough working conditions. The fault signature in such conditions is rather weak due to the complex planetary structure and the low rotating speed. Hence, the diagnosis of planetary gearbox problems in low-speed working conditions is considered as a bottleneck issue. In view of this, a rotary encoder signal, instead of conventional vibration, is initially applied to capture the fault-related information from the low-speed planetary gearbox. Then, a periodic group sparse-robust principal component analysis (PGS-RPCA) model with adaptive parameter programming, called adaptive PGS-RPCA (APGS-RPCA) is presented to extract the weak fault transient immersed in harmonic interferences and heavy noise. Finally, the effectiveness of the presented APGS-RPCA approach is verified via an experimental encoder signal at a very low input frequency. The diagnostic results show that the presented approach is superior to the conventional approach, and it may provide a promising solution for health monitoring of low-speed rotating machinery.
Hyaluronic acid functionalized biodegradable mesoporous silica nanocomposites for efficient photothermal and chemotherapy in breast cancer
Authors: Zhan Wenhua , Li Hanrui , Guo Yingying , Yang Lu , Pang Liaojun , Zhang Chaolin 
Published: January 2021

Abstract
Chemotherapy is one of conventional treatment methods for breast cancer, but drug toxicity and side effects have severely limited its clinical applications. Photothermal therapy has emerged as a promising method that, upon combination with chemotherapy, can better treat breast cancer. In this context, a biodegradable mesoporous silica nanoparticle (bMSN NPs) system was developed for loading doxorubicin (DOX) and IR780, to be potentially applied in the treatment of breast cancer. IR780 is encapsulated in the pores of bMSN NPs by hydrophobic adsorption, while DOX is adsorbed on the surface of the bMSN NPs by hyaluronic acid electrostatically, to form the bMID NPs. Transmission electron microscopy, fluorescence spectrum and UV absorption spectrum are used to prove the successful encapsulation of IR780 and the loading of DOX. In vitro experiments have shown bMID NPs present an excellent therapeutic effect on breast cancer cells. In vivo fluorescence imaging results have indicated that bMID NPs can accumulate in tumor sites gradually and achieve in vivo long-term circulation and continuous drug release. Furthermore, bMID NPs have provided obvious antitumor effects in breast cancer mouse models, thus evolving as an efficient platform for breast cancer therapy.
Wurtzite phase control for self-assisted GaAs nanowires grown by molecular beam epitaxy
Authors: Dursap T , Vettori M , Botella C , Regreny P , Blanchard N , Gendry M , Chauvin N , Bugnet M , Danescu A , Penuelas J 
Published: January 2021

Abstract
The accurate control of the crystal phase in III–V semiconductor nanowires (NWs) is an important milestone for device applications. Although cubic zinc-blende (ZB) GaAs is a well-established material in microelectronics, the controlled growth of hexagonal wurtzite (WZ) GaAs has thus far not been achieved successfully. Specifically, the prospect of growing defect-free and gold catalyst-free wurtzite GaAs would pave the way towards integration on silicon substrate and new device applications. In this article, we present a method to select and maintain the WZ crystal phase in self-assisted NWs by molecular beam epitaxy. By choosing a specific regime where the NW growth process is a self-regulated system, the main experimental parameter to select the ZB or WZ phase is the V/III flux ratio. Using an analytical growth model, we show that the V/III flux ratio can be finely tuned by changing the As flux, thus driving the system toward a stationary regime where the wetting angle of the Ga droplet can be maintained in the range of values allowing the formation of pure WZ phase. The analysis of the in situ reflection high energy electron diffraction evolution, combined with high-resolution scanning transmission electron microscopy (TEM), dark field TEM, and photoluminescence all confirm the control of an extended pure WZ segment, more than a micrometer long, obtained by molecular beam epitaxy growth of self- assisted GaAs NWs with a V/III flux ratio of 4.0. This successful controlled growth of WZ GaAs suggests potential benefits for electronics and opto-electronics applications.
Growth of long III-As NWs by hydride vapor phase epitaxy
Authors: Gil Evelyne , Andre Yamina 
Published: January 2021

Abstract
In this review paper, we focus on the contribution of hydride vapor phase epitaxy (HVPE) to the growth of III-As nanowires (NWs). HVPE is the third epitaxial technique involving gaseous precursors together with molecular beam epitaxy (MBE) and metal-organic VPE (MOVPE) to grow III–V semiconductor compounds. Although a pioneer in the growth of III–V epilayers, HVPE arrived on the scene of NW growth the very last. Yet, HVPE brought different and interesting insights to the topic since HVPE is a very reactive growth system, exhibiting fast growth property, while growth is governed by the temperature-dependent kinetics of surface mechanisms. After a brief review of the specific attributes of HVPE growth, we first feature the innovative polytypism-free crystalline quality of cubic GaAs NWs grown by Au-assisted vapor–liquid–solid (VLS) epitaxy, on exceptional length and for radii down to 6 nm. We then move to the integration of III–V NWs with silicon. Special emphasis is placed on the nucleation issue experienced by both Au-assisted VLS MOVPE and HVPE, and a model demonstrates that the presence of Si atoms in the liquid droplets suppresses nucleation of NWs unless a high Ga concentation is reached in the catalyst droplet. The second known issue is the amphoteric behavior of Si when it is used as doping element for GaAs. On the basis of compared MBE and HVPE experimental data, a model puts forward the role of the As concentration in the liquid Au–Ga–As–Si droplets to yield p-type (low As content) or n-type (high As content) GaAs:Si NWs. We finally describe how self-catalysed VLS growth and condensation growth are implemented by HVPE for the growth of GaAs and InAs NWs on Si.
Three-phase composites of NiFe2O4/Ni@C nanoparticles derived from metal-organic frameworks as electrocatalysts for the oxygen evolution reaction
Authors: Wei Xuedong , Liu Nan , Chen Weifeng , Qiao Shuangyan , Chen Yuanzhen 
Published: January 2021

Abstract
Composite electrocatalysts of carbon and metals or metal compounds with homogeneous active sites can be obtained through the carbonization of metal organic framework (MOF) materials under inert atmosphere. In this work, a three-phase composite electrocatalysts NiFe2O4/Ni@C were prepared via pyrolysis from self-assembled MOF nanosheets aggregates. The excellent electrocatalytic activity of the obtained electrocatalysts with various Ni:Fe ratios is demonstrated. Especially, the NiFe2O4/Ni@C sample with the mole ratio of Ni:Fe = 1:1 can use the overpotential (η) of 330 and 423 mV to drive 10 and 50 mA cm−2 respectively. After 80 000 s/22 h, the current density could retained 90% of the initial current density. The excellent activity and stability of the electrocatalysts are attributed to nickel and iron ions with uniform dispersion at atomic level in the NiFe2O4 phase and the synergistic effect of nickel and NiFe2O4 nanoparticles with amorphous carbon atoms or nanoparticles around.
Mn2+ ions incorporated into ZnS
x
Se1−x
colloidal quantum dots: controlling size and composition of nanoalloys and regulating magnetic dipolar interactions
Authors: Sevim Ünlütürk Seçil , Akdoğan Yaşar , Özçelik Serdar 
Published: January 2021

Abstract
A facile synthesis method is introduced how to prepare magnetically active ultraviolet emitting manganese ions incorporated into ZnS
x
Se1−x
colloidal quantum dot (nanoalloy) at 110 °C in aqueous solutions. The reaction time is the main factor to control the hydrodynamic size from 3 to 10 nm and the precursor ratio is significant to tune the alloy composition. ZnS shell layer on the ZnS
x
Se1−x
core was grown to passivate environmental effects. The nanoalloy has ultraviolet emission at 380 nm having a lifetime of 80 ns and 7% quantum yield. The incorporation of Mn2+ ions into the nanoalloys induced magnetic activity but did not modify the structure and photophysical properties of the nanoalloys. Colloidal and powdery samples were prepared and analyzed by electron paramagnetic resonance (EPR) spectroscopy. In the colloidal dispersions, EPR spectra showed hyperfine line splitting regardless of the Mn2+ ion fractions, up to 6%, indicating that Mn2+ ions incorporated into the nanoalloys were isolated. EPR signals of the powdery samples were broadened when the fraction of Mn2+ ions was higher than 0.1%. The EPR spectra were simulated to reveal the locations and interactions of Mn2+ ions. The simulations suggest that the Mn2+ ions are located on the nanoalloy surfaces. These findings infer that the magnetic dipolar interactions are regulated by the initial mole ratio of Mn/Zn and the physical state of the nanoalloys adjusted by preparation methods.
How do I introduce Schrödinger equation during the quantum mechanics course?
Authors: Mart T 
Published: January 2021

Abstract
In this paper I explain how I usually introduce the Schrödinger equation during the quantum mechanics course. My preferred method is the chronological one. Since the Schrödinger equation belongs to a special case of wave equations I start the course with introducing the wave equation. The Schrödinger equation is derived with the help of the two quantum concepts introduced by Max Planck, Einstein, and de Broglie, i.e. the energy of a photon E = ћω and the wavelength of the de Broglie wave λ = h/p. Finally, the difference between the classical wave equation and the quantum Schrödinger one is explained in order to help the students to grasp the meaning of quantum wavefunction

Ψ
(

r

,
t
)

. A comparison of the present method to the approaches given by the authors of quantum mechanics textbooks as well as that of the original Nuffield A level is presented. It is found that the present approach is different from those given by these authors, except by Weinberg or Dicke and Wittke. However, the approach is in line with the original Nuffield A level one.