bluuebunny/crossref_metadata_2025 huggingface dataset:
Metal organic framework-derived porous Fe2N nanocubes by rapid-nitridation for efficient photocatalytic hydrogen evolution
Authors: Cheng Zhixing , Saad Ali , Adimi Samira , Guo Haichuan , Liu Siqi , Thomas Tiju , Yang Minghui
Published: June 2020

A new means of producing MOF derived TMN materials, which in conjunction with suitable dyes, offer high-efficiency and low-cost avenues for making photocatalysts for hydrogen production.
A photochemical transformation of cyclic peptides leading to formation of selenolanthionine bridges
Authors: Waliczek Mateusz , Pehlivan Özge , Stefanowicz Piotr
Published: June 2020

Peptides with diselenide bridge under UV irradiation eliminate one selenium atom forming selenoether bond with good yield.
Understanding the reactivity of carbene-analogous phosphane complexes with group 13 elements as a central atom: a theoretical investigation
Authors: Zhang Zheng-Feng , Li Tsung-Lung , Su Ming-Der
Published: June 2020

The reactions of carbenic cations (PtBu3)2M+ (M = B, Al, Ga, In, and Tl) with methane and ethene are studied using density functional theory.
A recyclable heterogeneous nanocatalyst of copper-grafted natural asphalt sulfonate (NAS@Cu): characterization, synthesis and application in the Suzuki–Miyaura coupling reaction
Authors: Kohzadi Homa , Soleiman-Beigi Mohammad
Published: June 2020

NAS@Cu has synthesis simplicity given the availability of natural materials and has advantages such as being eco-friendly, high reactivity and recyclability.
A transition metal-free approach towards the regioselective synthesis of β-carboline tethered pyrroles and 2,3-dihydro-1H-pyrroles
Authors: Singh Manpreet , Paul Avijit Kumar , Singh Virender
Published: June 2020

A transition metal-free one-pot sequential approach has been unfolded for the synthesis of β-carboline tethered pyrroles and 2,3-dihydro-1H-pyrroles by using highly diverse 1-formyl-9H-β-carbolines as a template.
In situfabrication of a rose-shaped Co2P2O7/C nanohybridviaa coordination polymer template for supercapacitor application
Authors: Zhang Jiaxin , Liu Peng , Bu Ranran , Zhang Hao , Zhang Qi , Liu Kang , Liu Yanru , Xiao Zhenyu , Wang Lei
Published: June 2020

Using a coordination polymer as the template, the porous rose-shaped Co2P2O7/C-Xwere fabricated byin situhybrid Co2P2O7nanoparticles and nanocarbon for supercapacitor applications.
Relevant aspects of the conversion of guaiacol as a model compound for bio-oil over supported molybdenum oxycarbide catalysts
Authors: Blanco Elodie , Aguirre-Abarca Diego A. , Díaz de León J. Noé , Escalona Néstor
Published: June 2020

Molybdenum supported over activated carbon has been carburized under carbothermal hydrogen reduction conditions at different temperatures in order to modify the carburization degree and evaluated for guaiacol conversion.
Development of a novel carboxamide-based off–on switch fluorescence sensor: Hg2+, Zn2+ and Cd2+
Authors: Kiani Mahsa , Bagherzadeh Mojtaba , Meghdadi Soraia , Rabiee Navid , Abbasi Alireza , Schenk-Joß Kurt , Tahriri Mohammadreza , Tayebi Lobat , Webster Thomas J.
Published: June 2020

Here, the carboxamide ligand N-(thiazole-2-yl) picolinamide (L) was synthesized in an ionic liquid tetrabutylammonium bromide (TBAB) as the benign reaction medium.
Separation of ethane and ethylene by a robust ethane-selective calcium-based metal–organic framework
Authors: Lin Yuhan , Li Yuzhe , Wang Hao , Luo Dawei , Lin Feng , Li Jing
Published: June 2020

Adsorption and separation of ethane and ethylene has been studied on a robust Ca-based microporous metal–organic framework which shows ethane-selective adsorption over ethylene.
Correction: Second-order nonlinear optical properties of eight-membered centrosymmetric cyclic borasiloxanes
Authors: Gopalakrishnan Mohan , Viswanathan Thamodharan , David Ezhumalai , Thirumoorthy Krishnan , Bhuvanesh Nattamai S. P. , Palanisami Nallasamy
Published: June 2020

Correction for ‘Second-order nonlinear optical properties of eight-membered centrosymmetric cyclic borasiloxanes’ by Mohan Gopalakrishnan et al., New J. Chem., 2019, 43, 10948–10958, DOI: 10.1039/C9NJ01611B.
Ultrahigh electrocatalytic activity with trace amounts of platinum loadings on free-standing mesoporous titanium nitride nanotube arrays for hydrogen evolution reactions
Authors: Zhao Jiayang , Zeng Yan , Wang Jiao , Xu Qizhi , Chen Rongsheng , Ni Hongwei , Cheng Gary J.
Published: June 2020

Minimizing Pt loadings on electrocatalysts for hydrogen evolution reactions (HERs) is essential for their commercial applications.
In situ X-ray emission and high-resolution X-ray absorption spectroscopy applied to Ni-based bimetallic dry methane reforming catalysts
Authors: Beheshti Askari Abbas , al Samarai Mustafa , Hiraoka Nozomu , Ishii Hirofumi , Tillmann Lukas , Muhler Martin , DeBeer Serena
Published: June 2020

The effect of cobalt on the catalytic activity of a NiCoO dry methane reforming catalyst was investigated by in situ XES and HERFD XAS. Co is shown to hamper the reduction of the Ni in the NiCoO catalyst by modulation of its electronic structure.
A direct Z-scheme PtS2/arsenene van der Waals heterostructure with high photocatalytic water splitting efficiency
Authors: Ren Kai , Tang Wencheng , Sun Minglei , Cai Yongqing , Cheng Yuan , Zhang Gang
Published: June 2020

To overcome current serious energy and environmental issues, photocatalytic water splitting holds great promise because it requires only solar energy as an energy input to produce hydrogen.
A mesoporous encapsulated nanozyme for decontaminating two kinds of wastewater and avoiding secondary pollution
Authors: Wang Faming , Zhang Yan , Liu Zhengwei , Ren Jinsong , Qu Xiaogang
Published: June 2020

A complex nanozyme with dual enzyme mimic activities has been constructed by confining Au/Pt/Co tri-metal in a macroporous silica scaffold. The nanozyme has a huge advantage in treating different sewages in one system.
Dimerization of conserved ascaroside building blocks generates species-specific male attractants in Caenorhabditis nematodes
Authors: Dong Chuanfu , Dolke Franziska , Bandi Siva , Paetz Christian , von Reuß Stephan H.
Published: June 2020

Comparative ascaroside profiling of Caenorhabditis nematodes using HPLC-ESI-(−)-MS/MS precursor ion scanning revealed a class of highly species-specific ascaroside dimers.
Highly stretchable, self-healing, and 3D printing prefabricatable hydrophobic association hydrogels with the assistance of electrostatic interaction
Authors: Chen Heng , Hao Beibei , Ge Penghui , Chen Shaojun
Published: June 2020

Self-healing and 3D printing prefabricatable physically crosslinked hydrogels were prepared by copolymerization of butyl acrylate, 2-(dimethylamino)ethyl methacrylate, and methacrylic acid, followed by soaking in water.
Simplifying the synthesis of carbon inverse opals
Authors: McNulty David , Landgraf Victor , Trabesinger Sigita
Published: June 2020

A simplified synthesis method to prepare carbon inverse opals is presented, which is applicable to other inverse opal materials.
Effective in vitro delivery of paclitaxel by nanocargo of mesoporous polycaprolactone against triple negative breast cancer cells by minimalizing drug dose
Authors: Medhi Himadri , Khumukcham Saratchandra Singh , Manavathi Bramanandam , Paik Pradip
Published: June 2020

Porous-PCL-nanocapsules-Taxol is an effective nanomedicine for the treatment of triple negative breast cancer which can reduce the extent of side effects also.
Neural network activation similarity: a new measure to assist decision making in chemical toxicology
Authors: Allen Timothy E. H. , Wedlake Andrew J. , Gelžinytė Elena , Gong Charles , Goodman Jonathan M. , Gutsell Steve , Russell Paul J.
Published: June 2020

Deep learning neural networks, constructed for the prediction of chemical binding at 79 pharmacologically important human biological targets, show extremely high performance on test data (accuracy 92.2 ± 4.2%, MCC 0.814 ± 0.093, ROC-AUC 0.96 ± 0.04).
Pyrazolone ligation-mediated versatile sequential bioconjugations
Authors: Mailig Melrose , Liu Fa
Published: June 2020

A multiple component sequential bioconjugation chemistry establishes upon the joined force of hydrazine, β-keto ester, thiol and aldehyde.
Electrokinetic ion transport and fluid flow in a pH-regulated polymer-grafted nanochannel filled with power-law fluid
Authors: Barman Bhanuman , Kumar Deepak , Gopmandal Partha P. , Ohshima H.
Published: June 2020

In this article, we have discussed extensively electrokinetic ion transport and fluid flow through a slit polymer-grafted nanochannel filled with power-law fluid.
LncRNA Sox2ot modulates the progression of thoracic aortic aneurysm by regulating miR-330-5p/Myh11
Authors: Xiao Weizhang , Li Xing , Ji Cheng , Shi Jiahai , Pan Youmin
Published: June 2020

Thoracic aortic aneurysm (TAA) has been causing the death of elder people. Myosin heavy chain 11 (Myh11) has been reported associated with aortic aneurysm, but there is no specific study on its function on TAA. Here we aimed to explore the function of Myh11 on mouse aortic smooth muscle cells (SMCs) for studying the inner mechanism of TAA. H2O2 treatment was implemented on mouse aortic SMCs for detecting cell apoptosis. Meanwhile, functional assays were conducted to verify the function of Myh11 on mouse aortic SMCs. Also, pull-down assay, RIP assay were implemented to identify the potential RNAs for study. Quantitative real-time polymerase chain reaction (qRT-PCR) and luciferase reporter assay were implemented to identify the expression and binding relationships of RNAs. Myh11 expression was increased by treatment of H2O2. Myh11 could decrease proliferation and enhance apoptosis of mouse aortic SMCs. At the same time, mmu-miR-330-5p could bind to Myh11 and Sox2ot, forming a competing endogenous RNA (ceRNA) pathway to regulate the proliferation and apoptosis of mouse aortic SMCs. Moreover, both Sox2ot and Myh11 were proved to be up-regulated whereas miR-330-5p down-regulated in Fbn1C1039G/+ mice, the in vivo model of TAA. In a word, long noncoding RNA (lncRNA) Sox2ot modulates the progression of TAA by regulating miR-330-5p/Myh11 axis.
NLRP3 augmented resistance to gemcitabine in triple-negative breast cancer cells via EMT/IL-1β/Wnt/β-catenin signaling pathway
Authors: Zheng Qiao , Yao Dejiao , Cai Yi , Zhou Tiecheng
Published: June 2020

Background: Gemcitabine is widely used in the treatment of breast cancer (BC). However, the resistance to drugs remains a tough concern. The study explored the potential mechanism concerning gemcitabine resistance in triple-negative BC (TNBC) in vitro. Methods: TNBC cells (TNBCC) and gemcitabine-resistance cell lines (GRC) were used. We investigated the sensitivity to gemcitabine responsive to regulation of Nod-like receptor protein 3 (NLRP3) expression in TNBCC in different gemcitabine concentrations. RT-PCR checked NLRP3 mRNA expression and MTT assessed the cell cytotoxicity. Gemcitabine resistance was studied in GRC exposed to 0, 1, 3, 5 nm gemcitabine after GRC were treated with NLRP3 agonist Nigericin sodium salt (NSS) or antagonist CY-09. Epithelial-to-mesenchymal transition (EMT) biomarkers were evaluated via RT-PCR and inflammasome IL-1β, β-catenin content and GSK-3β activity were measured by ELISA methods. Last, we inactivated the signaling and examined the NLRP3, EMT mRNA expression by RT-PCR, IL-1β, β-catenin content and GSK-3β activity by ELISA and cell cytotoxicity through MTT. Results: NLRP3 up-regulation improved cell survival and reduced sensitivity to gemcitabine (P<0.05). NLRP3 had higher expression in GRC than TNBCC. GRC cell viability dropped as the gemcitabine concentration increased. NLRP3 up-regulation added to resistance to gemcitabine in GRC (P<0.05). NLRP3 agonist might induce EMT process, activate wnt/β-catenin signaling and IL-1β, while inactivation of wnt/β-catenin signaling could result in the inhibition of NLRP3, IL-1β and EMT as well as cell viability in GRC (P<0.05). Conclusion: NLRP3 could enhance resistance to gemcitabine via IL-1β/EMT/Wnt/β-catenin signaling, which suggested that NLRP3 antagonist CY-09 might be incorporated into gemcitabine treatment for TNBC.
Role of bioactive sphingolipids in physiology and pathology
Authors: Gomez-Larrauri Ana , Presa Natalia , Dominguez-Herrera Asier , Ouro Alberto , Trueba Miguel , Gomez-Muñoz Antonio
Published: June 2020

Sphingolipids are a class of complex lipids containing a backbone of sphingoid bases, namely the organic aliphatic amino alcohol sphingosine (Sph), that are essential constituents of eukaryotic cells. They were first described as major components of cell membrane architecture, but it is now well established that some sphingolipids are bioactive and can regulate key biological functions. These include cell growth and survival, cell differentiation, angiogenesis, autophagy, cell migration, or organogenesis. Furthermore, some bioactive sphingolipids are implicated in pathological processes including inflammation-associated illnesses such as atherosclerosis, rheumatoid arthritis, inflammatory bowel disease (namely Crohn’s disease and ulcerative colitis), type II diabetes, obesity, and cancer. A major sphingolipid metabolite is ceramide, which is the core of sphingolipid metabolism and can act as second messenger, especially when it is produced at the plasma membrane of cells. Ceramides promote cell cycle arrest and apoptosis. However, ceramide 1-phosphate (C1P), the product of ceramide kinase (CerK), and Sph 1-phosphate (S1P), which is generated by the action of Sph kinases (SphK), stimulate cell proliferation and inhibit apoptosis. Recently, C1P has been implicated in the spontaneous migration of cells from some types of cancer, and can enhance cell migration/invasion of malignant cells through interaction with a Gi protein-coupled receptor. In addition, CerK and SphK are implicated in inflammatory responses, some of which are associated with cancer progression and metastasis. Hence, targeting these sphingolipid kinases to inhibit C1P or S1P production, or blockade of their receptors might contribute to the development of novel therapeutic strategies to reduce metabolic alterations and disease.
Data Collection Methods for the Voice Range Profile: A Systematic Review
Authors: Cutchin Grace M. , Plexico Laura W. , Weaver Aurora J. , Sandage Mary J.
Published: June 2020

Purpose

To assess data collection variability in the voice range profile (VRP) across clinicians and researchers, a systematic review was conducted to evaluate the extent of variability of specific data collection points that affect the determination of frequency range and sound level and determine next steps in standardization of a VRP protocol.

Method

A systematic review was conducted using the Preferred Reporting Items for Systematic Review and Meta-Analysis checklist. Full-text journal articles were identified through PubMed, Web of Science, Psych Info, ProQuest Dissertations and Theses Global, Google Scholar, and hand searching of journals.

Results

A total of 1,134 articles were retrieved from the search; of these, 463 were duplicates. Titles and abstracts of 671 articles were screened, with 202 selected for full-text review. Fifty-four articles were considered eligible for inclusion. The information extracted from these articles revealed the methodology used to derive the VRP was extremely variable across the data points selected. Additionally, there were eight common acoustic measures used for statistical analysis described in included studies that were added as a data point.

Conclusions

The data collection methods for the VRP varied considerably. Standardization of procedures was recommended for clinicians and researchers.
Production of Morphosyntax Within and Across Different Dialects of American English
Authors: Hendricks Alison Eisel , Adlof Suzanne M.
Published: June 2020

Purpose

This study examined the production of morphosyntactic markers by school-age children with and without developmental language disorder. Comparisons were made between students who speak mainstream American English (MAE) dialects and nonmainstream American English (NMAE) dialects.

Method

First- and second-grade students (
N
= 82) completed assessments of dialect use and language ability, which are designed for students who speak NMAE dialects. Students also completed an experimental production task targeting three morphosyntactic features: past tense –
ed
marking, third-person singular –
s
marking, and plural –
s
marking. Past tense marking and third-person singular are produced differently across MAE and NMAE dialects, whereas plural marking is produced more similarly across dialects.

Results

When comparing across dialects, children with typical language skills who spoke NMAE dialects overtly marked past tense and third-person singular less often compared to MAE peers. However, when comparing to same-dialect peers with language disorders, children with typical language skills who spoke NMAE dialects overtly marked these morphosyntactic markers more often than peers with developmental language disorder.

Conclusion

The results underscore the importance of considering a child's dialect use when assessing language ability, in particular with measures that include features that are variable in NMAE dialects. At the same time, within-dialect comparisons suggest that a broader set of morphosyntactic features may provide useful information for evaluations of language ability. Future research should investigate the source of these differences, including the extent to which students with language disorders have acquired the social and linguistic factors that condition the use of variable features.
Online assessment of voltage stability using Newton‐Corrector algorithm
Authors: Ali Mazhar , Gryazina Elena , Khamisov Oleg , Sayfutdinov Timur
Published: June 2020

The real‐time robust and secure operation of power systems has become a challenging task, as the operating state evolves rapidly due to uncertainties associated with increasing renewable generation, less predictable loads, and various forms of contingencies. Therefore, an online voltage stability assessment is required to avoid any undesirable system behaviours or a large‐scale blackout. Such evaluation is not just difficult but also computationally intensive mainly due to the continuously changing state of a grid. This study presents a numerically robust and fast algorithm for online voltage stability assessment with ease of implementation and programming. The proposed approach updates distance of voltage collapse in real‐time by incorporating base‐case collapse point solution and incoming data from measurement devices. Implementation of the proposed algorithm is described in detail, and its performance is validated on different IEEE test cases.
Ground‐level DC electric field sensor for overhead HVDC/HVAC transmission lines in hybrid corridors
Authors: Cui Yong , Song Xiao , Wang Chen , Zhao Luxing , Wu Guifang
Published: June 2020

Measurement of electric fields is crucial for the evaluation of the electromagnetic environment in electric power transmission system. Due to limited transmission corridor resources, the hybrid transmission lines including high‐voltage alternating current and high‐voltage direct current (HVAC/HVDC) are more common nowadays. However, commonly used field‐mill direct current electric field sensors (DC EFSs) can only be used beneath HVDC lines and the emergence of alternating current (AC) electric fields has adversely affected measurement results recorded by DC EFS. In this work, a DC EFS was designed that is capable of measuring ground‐level DC electric fields generated by overhead HVAC/HVDC transmission lines in a hybrid corridor. A field‐mill structure was used to modulate the DC and AC hybrid electric field and then a narrow band‐pass filter was used to realise suppression of the AC electric field signal. Subsequently, the phase‐sensitive detection method was used to realise amplitude demodulation and phase discrimination of the DC electric field. Sensor prototypes based on the foregoing method were experimentally tested in the China national high‐voltage base. These DC EFSs could be mass‐produced conveniently from current field‐mill for hybrid corridors application.
Regional‐scale allocation of fast charging stations: travel times and distribution system reinforcements
Authors: Andrade José , Ochoa Luis F. , Freitas Walmir
Published: June 2020

Electric vehicle (EV) fleet is constantly increasing over the years and higher adoption is expected in the coming decades. A key aspect to support and boost the EV uptake is the adequate availability (number, locations and sizes) of fast charging stations (FCSs) to enable inter‐ and intra‐city travels. Since these studies require modelling large regions with uncertainties, a methodology able to provide the least‐cost solution is needed. This study proposes a scalable methodology that integrates high‐resolution traffic flow and multi‐phase electrical simulations to find the number, locations and sizes of FCSs at the least societal cost considering the uncertainties in driving patterns. It determines potential FCSs locations based on traffic flow and progressively explores these FCSs quantifying capital (equipment and land) and indirect (loss of productivity and reinforcements) costs to identify the least‐cost solution. Results from a Brazilian case study comprising of a metropolitan region with six cities and 26 primary substations show that, with high adoption of EVs, the investments in equipment represent the most significant components of societal cost. Moreover, for metropolitan regions, the societal least‐cost solution is found with more but smaller FCSs. Finally, is found that neglecting the loss of productivity can significantly affect the results.
Bi‐level service restoration strategy for active distribution system considering different types of energy supply sources
Authors: Li Zhenkun , Khrebtova Tetiana , Zhao Nan , Zhang Zhiquan , Fu Yang
Published: June 2020

With increasing power consumption and the number of active units, such as distributed generators (DGs), energy storage systems (ESSs), and transportable ESSs (TESSs), in the distribution system, the requirements for the operability of the power system restoration service increase as well. In this study, the authors propose a new bi‐level optimisation strategy for service restoration (SR) to minimise the final cost of the restoration process and to re‐energise the maximum number of customers. The proposed method considers different power resupply methodologies, such as topology reconfiguration‐based restoration, islanding operation of DG, and the application of TESS for SR, along with their optimal combination, to minimise the financial costs. The primary level comprises a reconfiguration approach and a genetic algorithm to optimise the islanding partition of an active distribution system; the second level consists of the fuzzy logic procedure to set up the combination of energy resources. In addition, this study considers the objective problem formulation as a combination of different subtasks, which represent the financial costs of various components during the restoration process. Case studies are conducted on a modified IEEE 39‐bus distribution network, where the validity and effectiveness of the proposed strategy are demonstrated.
Multi‐harmonic sources location based on sparse component analysis and complex independent component analysis
Authors: Wang Guangui , Ma Xiaoyang , Wang Weikang , Yang Honggeng , Chen Chang , Yang Qiuling
Published: June 2020

With the large‐scale deployment of power electronic equipment, harmonic sources in the power system are gradually increasing. Traditional harmonic source location methods are inaccurate and they usually require prior information of the location, which is difficult to obtain. This study presents a novel method of harmonic source location that can use less prior information to accurately locate the location of harmonic sources. First, a linear screening criterion is constructed using sparse component analysis. Then, the source signals separated by complex independent component analysis are filtered by linear and non‐Gaussian secondary screening, improving the accuracy of source signals and mixing matrix. Finally, the precise location of the harmonic is obtained by matching the mixing matrix with the columns of the matrix, which related to the system topology. Three IEEE systems are used to validate the proposed method. The simulation results show the high accuracy of the proposed method in the harmonic source location.
Investigating the impact of metallic nanoparticles on performance of nanowire‐based plasmonic photodetectors
Authors: Rashidi Mohammad , Asgari Asghar
Published: June 2020

In this study, the authors have theoretically investigated the effects of metallic nanoparticles (NPs) on the performance of nanowire‐based plasmonic photodetectors. For this goal, they propose a novel structure for plasmonic photodetectors in which the metallic NPs are deposited on a semiconductor nanowire sandwiched between two ohmic contacts. To calculate the eigenstates of the system, they have solved the Schrodinger equation for the nanowire in a nanostructure system with metallic NPs. Obtaining the system's eigenstates, the nanowires absorption coefficient, dielectric constant, and refractive index have been calculated. Also, the dependency of these parameters on the input wavelength has discussed. Besides, to find out the impact of metallic NPs, they have calculated the current of the system. They also have made a comparison of the system's responsivity in the simple condition (where there are no NPs effects) and the hybrid condition, in which the effects of NPs are also be considered. In fact, the effects of the NPs in the enhancement of the electrical field, and their role in the scattering of the field are the main fields of studies in this work.
A new fitting function for GRB MeV spectra based on the internal shock synchrotron model
Authors: Yassine M. , Piron F. , Daigne F. , Mochkovitch R. , Longo F. , Omodei N. , Vianello G.
Published: June 2020

Aims. The physical origin of the gamma-ray burst (GRB) prompt emission is still a subject of debate. Internal shock models have been widely explored, owing to their ability to explain most of the high-energy properties of this emission phase. While the Band function or other phenomenological functions are commonly used to fit GRB prompt emission spectra, we propose a new parametric function that is inspired by an internal shock physical model. We use this function as a proxy of the model to compare it easily to GRB observations.

Methods. We built a parametric function that represents the spectral form of the synthetic bursts provided by our internal shock synchrotron model (ISSM). We simulated the response of the Fermi instruments to the synthetic bursts and fit the obtained count spectra to validate the ISSM function. Then, we applied this function to a sample of 74 bright GRBs detected by the Fermi GBM, and we computed the width of their spectral energy distributions around their peak energy. For comparison, we also fit the phenomenological functions that are commonly used in the literature. Finally, we performed a time-resolved analysis of the broadband spectrum of GRB 090926A, which was jointly detected by the Fermi GBM and LAT. This spectrum has a complex shape and exhibits a power-law component with an exponential cutoff at high energy, which is compatible with inverse Compton emission attenuated by gamma-ray internal absorption.

Results. This work proposes a new parametric function for spectral fitting that is based on a physical model. The ISSM function reproduces 81% of the spectra in the GBM bright GRB sample, versus 59% for the Band function, for the same number of parameters. It gives also relatively good fits to the GRB 090926A spectra. The width of the MeV spectral component that is obtained from the fits of the ISSM function is slightly larger than the width from the Band fits, but it is smaller when observed over a wider energy range. Moreover, all of the 74 analyzed spectra are found to be significantly wider than the synthetic synchrotron spectra. We discuss possible solutions to reconcile the observations with the internal shock synchrotron model, such as an improved modeling of the shock microphysics or more accurate spectral measurements at MeV energies.
Investigating the lack of main-sequence companions to massive Be stars
Authors: Bodensteiner J. , Shenar T. , Sana H.
Published: June 2020

Context.About 20% of all B-type stars are classical Be stars – stars whose spectra imply the presence of a circumstellar decretion disk. The disk phenomenon is strongly correlated with rapid rotation, the origin of which remains unclear. It may be rooted in single- or binary-star evolution. In the framework of the binary channel, the initially more massive star transfers mass and angular momentum to the original secondary, which becomes a Be star. The system then evolves into a Be binary with a post-main-sequence companion, which, depending on the companion mass, may later be disrupted in a supernova event. Hence, if the binary channel dominates the formation of Be stars, one may expect a strong lack of close Be binaries with main sequence (MS) companions.

Aims.We want to test the prediction of the binary channel. Through an extensive, star-by-star review of the literature of a magnitude-limited sample of Galactic early-type Be stars, we investigate whether Be binaries with MS companions are known to exist.

Methods.Our sample is constructed from the BeSS database and cross-matched with all available literature on the individual stars. Archival and amateur spectra are used to verify the existing literature when conflicting reports are found.

Results.Out of an initial list of 505 Be stars, we compile a final sample of 287 Galactic Be stars earlier than B1.5 withV ≤ 12 mag. Out of those, 13 objects were reported as Be binaries with known post-MS companions (i.e., compact objects or helium stars) and 11 as binaries with unknown, uncertain or debated companions. We find no confirmed reports of Be binaries with MS companions. For the remaining 263 targets, no significant reports of multiplicity exist in the literature, implying that they are either Be binaries with faint companions, or truly single.

Conclusions.The clear lack of reported MS companions to Be stars, which stands in contrast to the high number of detected B+B MS binaries, strongly supports the hypothesis that early-type Be stars are binary interaction products that spun up after mass and angular momentum transfer from a companion star. Taken at face value, our results may suggest that a large majority of the early-type Be stars have formed through binary mass-transfer.
RASSINE: Interactive tool for normalising stellar spectra
Authors: Cretignier M. , Francfort J. , Dumusque X. , Allart R. , Pepe F.
Published: June 2020

Aims. We provide an open-source code allowing an easy, intuitive, and robust normalisation of spectra.

Methods. We developed RASSINE, a Python code for normalising merged 1D spectra through the concepts of convex hulls. The code uses six parameters that can be easily fine-tuned. The code also provides a complete user-friendly interactive interface, including graphical feedback, that helps the user to choose the parameters as easily as possible. To facilitate the normalisation even further, RASSINE can provide a first guess for the parameters that are derived directly from the merged 1D spectrum based on previously performed calibrations.

Results. For HARPS spectra of the Sun that were obtained with the HELIOS solar telescope, a continuum accuracy of 0.20% on line depth can be reached after normalisation with RASSINE. This is three times better than with the commonly used method of polynomial fitting. For HARPS spectra of α Cen B, a continuum accuracy of 2.0% is reached. This rather poor accuracy is mainly due to molecular band absorption and the high density of spectral lines in the bluest part of the merged 1D spectrum. When wavelengths shorter than 4500 Å are excluded, the continuum accuracy improves by up to 1.2%. The line-depth precision on individual spectrum normalisation is estimated to be ∼0.15%, which can be reduced to the photon-noise limit (0.10%) when a time series of spectra is given as input for RASSINE.

Conclusions. With a continuum accuracy higher than the polynomial fitting method and a line-depth precision compatible with photon noise, RASSINE is a tool that can find applications in numerous cases, for example stellar parameter determination, transmission spectroscopy of exoplanet atmospheres, or activity-sensitive line detection.
Spectromicroscopies électroniques : sonder les propriétés optiques de nanomatériaux avec des électrons rapides
Authors: Kociak Mathieu , Galvão Tizei Luiz Henrique , Meuret Sophie , Lourenço-Martins Hugo , Stephan Odile
Published: June 2020

Récemment, les microscopies électroniques à balayage et/ou en transmission se sont imposées comme des techniques de choix pour étudier les phénomènes optiques avec des résolutions spatiales bien meilleures que la limite de diffraction optique. Les spectroscopies de perte et de gain d’énergie, ainsi que la cathodoluminescence permettent ainsi d’étudier à une échelle pertinente des excitations comme les plasmons de surface dans les nanoparticules métalliques ou les excitons dans des structures confinées quantiquement.
Work and family conflict analysis of female entrepreneurs in Turkey and classification with rough set theory
Authors: Bozoğlu Batı Gülgönül , Armutlulu İsmail Hakkı
Published: June 2020

Entrepreneurs face numerous challenges and experience conflicts in their daily lives. However, it is clear that female entrepreneurs have more conflicts than male ones due to society’s perception of women and various expectations from them, and consequently, these conflicts affect women’s investment decisions. In this study, especially conflict levels of female entrepreneurs at work and in family have been investigated. Also, this study dwells upon how the roles that female entrepreneurs play in family and at work shape their investment plans and how the conflicts they experience affect their investment decisions. In this study, a total of 348 face-to-face interviews with female entrepreneurs, from the four major cities of the most economically developed region of Turkey, have been conducted, and various questions about demographic characteristics, business characteristics, entrepreneurship densities, business, and family conflict situations and investment plans have been asked. The obtained data has been analyzed and classified via rough set theory. The correlative relationship between conflict and investment decision has also been demonstrated. This paper contributes to the extant literature - in which there is an essential gap relating to female entrepreneurs in Turkey - by describing their status, conflict levels and investment decisions with quantitative data. The study presents a new perspective on the classification of female entrepreneurs with a rough set theory which is considered to be superior to other classification methods in terms of classifying objects with the same characteristics according to different decision situations.
Investigate the mechanical property of nanopolycrystal silicon by means of the nanoindentation method
Authors: Han Xuesong
Published: June 2020

A comprehensive understanding of the basic deformation mechanisms is essential for novel nanomaterials with unique properties for engineering applications. Unfortunately, nanopolycrystal materials with smaller grains are difficult prepare, which makes the study of the deformation process difficult using experiments. The molecular dynamics (MD) method has already been proved to be an efficient tool kit for the nanoscale phenomenon and was gradually adopted by many researchers to investigate the mechanical deformation of nanocrystalline materials. This manuscript studies the mechanical response of specimens with internal grains separated by high angle boundaries without porosities and impurities using MD simulation methods. The results demonstrate that the partial dislocation activity takes over in nanocrystalline materials if the grain sizes are large enough. The distribution of the ideal crystal structure along the radial direction remains almost unchanged, which justifies that little lateral deformation is induced. The animation shows that many atoms are stripped by the feeding of the indenter. This type of atom removal (moves just like rain flow) is different from any kind of material stripping in the macroscopic scale. Therefore, the deformation of the substrate is generated by the coupling of dislocation and atom sliding. The distribution of dislocation is more suitable for characterizing materials deformation at small scale. In addition, a novel cone-shaped dislocation distribution is observed. With the feeding of tools, the amount of screw dislocation gradually increases while the amount of the edge dislocation gradually decreases. The simulation results also show that the grain boundary exhibits higher self-diffusivities than the perfect lattice, which is helpful in grain boundary sliding.
Selective modulation of plasma parameters in an atmospheric dielectric barrier discharge driven by sawtooth-type tailored voltage waveforms
Authors: Zhang Z. , Nie Q. , Wang Z. , Lim J. W. M.
Published: June 2020

Tailored voltage waveforms, formed by a fundamental frequency waveform superimposed with higher harmonics, show promise in realizing independent control and optimization of plasma parameters in conventional atmospheric dielectric barrier discharge systems (DBDs). In this paper, a self-consistent fluid model developed by a semi-kinetic treatment of electrons is applied to study the dependency of the electron energy and density distributions on the number of applied higher harmonics, applied fundamental frequency, and contributions from secondary electron emission—in a DBD system driven by tailored voltage waveforms. The mechanisms for achieving selective control over the modulated parameters are proposed, which allow for optimal selection of applied parameters for various downstream applications. This work exhibits dual-advantages for its novelty in presenting practical methods to modulate atmospheric plasma parameters, while in-depth analysis and discussions reveal underlying theoretical principles for the modulation of plasma parameters in atmospheric pressure discharges driven by tailored voltage waveforms.
Using electronegativity and hardness to test density functionals
Authors: Moltved Klaus A. , Kepp Kasper P.
Published: June 2020

Density functional theory (DFT) is used in thousands of papers each year, yet lack of universality reduces DFT’s predictive capacity, and functionals may produce energy-density imbalances. The absolute electronegativity (χ) and hardness (η) directly reflect the energy–density relationship via the chemical potential ∂E/∂N and we thus hypothesized that they probe universality. We studied χ and η for atoms Z = 1–36 using 50 diverse functionals covering all major classes. Very few functionals describe both χ and η well. η benefits from error cancellation, whereas χ is marred by error propagation from IP and EA; thus, almost all standard GGA and hybrid functionals display a plateau in the MAE at ∼0.2 eV–0.3 eV for η. In contrast, variable performance for χ indicates problems in describing the chemical potential by DFT. The accuracy and precision of a functional is far from linearly related, yet for a universal functional, we expect linearity. Popular functionals such as B3LYP, PBE, and revPBE perform poorly for both properties. Density sensitivity calculations indicate large density-derived errors as occupation of degenerate p- and d-orbitals causes “non-universality” and large dependency on exact exchange. Thus, we argue that performance for χ for the same systems is a hallmark of an important aspect of universality by probing ∂E/∂N. With this metric, B98, B97-1, PW6B95D3, MN-15, rev-TPSS, HSE06, and APFD are the most “universal” among the tested functionals. B98 and B97-1 are accurate for very diverse metal–ligand bonds, supporting that a balanced description of ∂E/∂N and ∂E2/∂N2, via χ and η, is probably a first simple probe of universality.
Chemical approaches to artificial photosynthesis: A molecular, dye-sensitized photoanode for O2 production prepared by layer-by-layer self-assembly
Authors: Wang Degao , Farnum Byron H. , Dares Christopher J. , Meyer Thomas J.
Published: June 2020

We describe here the preparation of a family of photoanodes for water oxidation that incorporate an electron acceptor–chromophore–catalyst in single molecular assemblies on nano-indium tin oxide (nanoITO) electrodes on fluorine-doped tin oxide (FTO). The assemblies were prepared by using a layer-by-layer, Atomic Layer Deposition (ALD), self-assembly approach. In the procedure, addition of an electron acceptor viologen derivative followed by a RuII(bpy) chromophore and a pyridyl derivative of the water oxidation catalyst [Ru(bda) (L)2] (bda = 2,2′-bipyridine-6,6′-dicarboxylate)2, were linked by ALD by addition of the bridge precursors TiO2, ZrO2, and Al2O3 as the bridging groups giving the assemblies, FTO|nanoITO|–MV2+–ALD MO2–RuP22+–ALD M′O2–WOC. In a series of devices, the most efficient gave water oxidation with an incident photon to current efficiency of 2.2% at 440 nm. Transient nanosecond absorption measurements on the assemblies demonstrated that the slow step in the intra-assembly electron transfer is the electron transfer from the chromophore through the viologen bridge to the nanoITO electrode.
Carrier recombination processes in Fe-doped GaN studied by optical pump–probe techniques
Authors: Ščajev Patrik , Jarašiūnas Kęstutis , Leach Jacob
Published: June 2020

We applied time-resolved free carrier absorption and light-induced transient grating techniques for monitoring carrier dynamics in lightly Fe-doped GaN bulk crystals. Comparison of measured decay times at single- and two-photon carrier photoexcitation with those reported for higher Fe doping revealed two different branches of lifetime dependence on iron density. A deeper insight was reached by using different wavelengths for probing carrier dynamics, which enabled discrimination of electron and hole capture processes by Fe ions. The capture cross section for holes, σh = (4 ± 1) × 10−15 cm2 for the Fe2+* state (5E → 4T2 transition) was determined to be ten times larger than that for electrons, σe = (4 ± 1) × 10−16 cm2 for the Fe3+* state (4T1 → 3T1 transition). Thermal activation of the [Fe2+(5T2),hVB] complex, where hVB is a free hole, required an energy of 315 meV. Light-induced transient grating decay revealed decreasing diffusivity of electrons with Fe doping due to initial carrier capture to Fe3+ states. Simultaneous measurements of carrier diffusion coefficient and lifetime at low excitation conditions (3 × 1017 cm−3) revealed a decrease of bipolar diffusion length from 2 μm in the undoped GaN down to 0.08 μm in the Fe-doped samples at 300 K.
High performance high power textured piezoceramics
Authors: Liu Hairui , Yan Yongke , Leng Haoyang , Heitmann Adam , Blottman John B. , Priya Shashank
Published: June 2020

Crystallographic grain-oriented ceramics (also referred to as textured ceramics) are known to exhibit a high soft piezoelectric response. However, the role of texturing in hard piezoelectric materials is not well understood and it has been difficult to obtain a balance of hard and soft properties in the same material. Here, we investigate the hard and soft piezoelectric behavior of [001]PC-textured 0.05Pb(Mn1/3Sb2/3)O3-0.95[0.4Pb(Mg1/3Nb2/3)O3-0.25PbZrO3-0.35PbTiO3] (PMnS-PMN-PZT) ceramics to illustrate the influence of texturing degree. The results demonstrate that textured PMnS-PMN-PZT ceramics exhibit a 170% higher longitudinal mode piezoelectric coefficient (d33) with only 16% reduction in the mechanical quality factor (Qm). Random PMnS-PMN-PZT ceramics were found to exhibit a d33 of 259 pC/N and a Qm of 982, while textured ceramics sintered at the same temperature demonstrated a d33 of 445 and a Qm of 824. Electric field dependent x-ray diffraction is utilized to confirm the existence of internal bias generated from defect dipoles, providing the signature for hard behavior. Temperature dependent measurement of d33 and Qm for textured PMnS-PMN-PZT ceramics indicated high stability up to 120 °C.
Simulation of XFEL induced fluorescence spectra of hollow ions and studies of dense plasma effects
Authors: Deschaud B. , Peyrusse O. , Rosmej F. B.
Published: June 2020

X-ray free electron laser (XFEL) interaction with solids has been simulated to resolve simultaneously variable XFEL photon energy and x-ray spectral distribution of the target emission (2D-maps). It is discovered that the highly transient charge state distribution exhibits a characteristic target response due to the action of the sharply rising radiation field. Finally, we identify advantageous features for studies of dense plasma effects of two K-shell vacancy hollow ion x-ray emission excited via resonance excitation. These features and characteristics permit the global study of dense plasma effects via the simulation of the time-integrated joint distribution of pumped and fluorescence energies. It is shown that the simulation of these specific 2D-maps offers a global vision of the complex interplay between different processes or phenomena such as photoionization, resonance excitation, or ionization potential depression.
Revealing the importance of light extraction efficiency in InGaN/GaN microLEDs via chemical treatment and dielectric passivation
Authors: Ley Ryan T. , Smith Jordan M. , Wong Matthew S. , Margalith Tal , Nakamura Shuji , DenBaars Steven P. , Gordon Michael J.
Published: June 2020

Chemical etching and Al2O3 dielectric passivation were used to minimize nonradiative sidewall defects in InGaN/GaN microLEDs (mesa diameter = 2–100 μm), resulting in an increase in external quantum efficiency (EQE) as the LED size was decreased. Peak EQEs increased from 8%–10% to 12%–13.5% for mesa diameters from 100 μm to 2 μm, respectively, and no measurable leakage currents were seen in current density–voltage (J–V) characteristics. The position and shape of EQE curves for all devices were essentially identical, indicating size-independent ABC model (Shockley–Read–Hall, radiative, and Auger recombination) coefficients-behavior that is not typical of microLEDs as the size decreases. These trends can be explained by enhancement in light extraction efficiency (LEE), which is only observable when sidewall defects are minimized, for the smallest LED sizes. Detailed ray-tracing simulations substantiate the LEE enhancements.
Enhancement of acoustic spin pumping by acoustic distributed Bragg reflector cavity
Authors: Hwang Yunyoung , Puebla Jorge , Xu Mingran , Lagarrigue Aurelien , Kondou Kouta , Otani Yoshichika
Published: June 2020

Surface acoustic waves (SAWs) in the GHz frequency range can inject spin currents dynamically into adjacent non-magnetic layers via the spin pumping effect associated with ferromagnetic resonance. Here, we demonstrate an enhancement of acoustic ferromagnetic resonance and spin current generation by a pair of SAW reflector gratings, which form an acoustic analog of the distributed Bragg reflector cavity. In the experiment, we confirmed 2.04 ± 0.02 times larger SAW power absorption in a device with cavity than in the case of no acoustic cavity. We confirmed up to 2.96 ± 0.02 times larger spin current generation by measuring electric voltages generated by the inverse Edelstein effect at the interface between Cu and Bi2O3. The results suggest that acoustic cavities would be useful to enhance the conversion efficiency in SAW driven coupled magnon–phonon dynamics.