bluuebunny/crossref_metadata_2025 huggingface dataset:
GPU-based, interactive exploration of large spatiotemporal climate networks
Authors: Buschmann Stefan , Hoffmann Peter , Agarwal Ankit , Marwan Norbert , Nocke Thomas
Published: April 2023

This paper introduces the Graphics Processing Unit (GPU)-based tool Geo-Temporal eXplorer (GTX), integrating a set of highly interactive techniques for visual analytics of large geo-referenced complex networks from the climate research domain. The visual exploration of these networks faces a multitude of challenges related to the geo-reference and the size of these networks with up to several million edges and the manifold types of such networks. In this paper, solutions for the interactive visual analysis for several distinct types of large complex networks will be discussed, in particular, time-dependent, multi-scale, and multi-layered ensemble networks. Custom-tailored for climate researchers, the GTX tool supports heterogeneous tasks based on interactive, GPU-based solutions for on-the-fly large network data processing, analysis, and visualization. These solutions are illustrated for two use cases: multi-scale climatic process and climate infection risk networks. This tool helps one to reduce the complexity of the highly interrelated climate information and unveils hidden and temporal links in the climate system, not available using standard and linear tools (such as empirical orthogonal function analysis).
Ice nucleation in aqueous solutions of short- and long-chain poly(vinyl alcohol) studied with a droplet microfluidics setup
Authors: Eickhoff Lukas , Keßler Mira , Stubbs Christopher , Derksen Jakob , Viefhues Martina , Anselmetti Dario , Gibson Matthew I. , Hoge Berthold , Koop Thomas
Published: April 2023

Poly(vinyl alcohol) (PVA) has ice binding and ice nucleating properties. Here, we explore the dependence of the molecular size of PVA on its ice nucleation activity. For this purpose, we studied ice nucleation in aqueous solutions of PVA samples with molar masses ranging from 370 to 145 000 g mol−1, with a particular focus on oligomer samples with low molar mass. The experiments employed a novel microfluidic setup that is a follow-up on the previous WeIzmann Supercooled Droplets Observation on a Microarray (WISDOM) design by Reicher et al. The modified setup introduced and characterized here, termed nanoliter Bielefeld Ice Nucleation ARraY (nanoBINARY), uses droplet microfluidics with droplets (96 ± 4) µm in diameter and a fluorinated continuous oil phase and surfactant. A comparison of homogeneous and heterogeneous ice nucleation data obtained with nanoBINARY to those obtained with WISDOM shows very good agreement, underpinning its ability to study low-temperature ice nucleators as well as homogeneous ice nucleation due to the low background of impurities. The experiments on aqueous PVA solutions revealed that the ice nucleation activity of shorter PVA chains strongly decreases with a decrease in molar mass. While the cumulative number of ice nucleating sites per mass n m of polymers with different molar masses is the same, it becomes smaller for oligomers and completely vanishes for dimer and monomer representatives such as 1,3-butanediol, propan-2-ol, and ethanol, most likely because these molecules become too small to effectively stabilize the critical ice embryo. Overall, our results are consistent with PVA polymers and oligomers acting as heterogeneous ice nucleators.
Theoretical investigation of braking of tearing mode rotation by resistive walls in ITER
Authors: Fitzpatrick R.
Published: April 2023

The locking of the 2/1 tearing mode to the resistive wall in the ITER tokamak (15 MA inductive scenario 2) is investigated theoretically using a cylindrical asymptotic matching model. The model takes into account the fact that ITER plasmas will effectively be surrounded by two walls; the inner blanket module layer with a time constant of about 23 ms, and the outer vacuum vessel with a time constant of about 380 ms. The model also takes cognizance of the fact that neither the blanket module layer nor the vacuum vessel can be accurately described as “thin” walls (in the ordinarily accepted sense). The model incorporates changes in both the plasma poloidal and the toroidal angular velocity profiles, in response to the electromagnetic braking torque that develops at the rational surface, because it turns out that neoclassical poloidal flow-damping is not strong enough to completely suppress changes in the poloidal velocity. Finally, the model accurately calculates changes in the poloidal and toroidal plasma angular velocity profiles by evolving the full angular equations of motion, taking the electromagnetic braking torque, plasma inertia, plasma viscosity, and poloidal flow-damping into account. The time required for the 2/1 tearing mode to grow from a small amplitude to a sufficient one to lock to the walls is found to be about 3.5 s. The critical full radial island width at which wall locking is triggered is found to be about 9% of the plasma minor radius.
Low-threshold lasing of optically pumped micropillar lasers with Al0.2Ga0.8As/Al0.9Ga0.1As distributed Bragg reflectors
Authors: Shih Ching-Wen , Limame Imad , Krüger Sebastian , Palekar Chirag C. , Koulas-Simos Aris , Brunner Daniel , Reitzenstein Stephan
Published: April 2023

We report on the design, realization, and characterization of optically pumped micropillar lasers with low-absorbing Al0.2Ga0.8As/Al0.9Ga0.1As dielectric Bragg reflectors (DBRs) instead of commonly used GaAs/AlGaAs DBRs. A layer of (In, Ga)As quantum dots is embedded in the GaAs λ-cavity of as an active medium. We experimentally study the lasing characteristics of the fabricated micropillars by means of low-temperature photoluminescence with varying pump laser wavelength between 532 and 899 nm. The incorporation of 20% Al content in the DBRs opens an optical pumping window from 700 to 820 nm, where the excitation laser light can effectively reach the GaAs cavity above its bandgap while remaining transparent to the DBRs. This results in a substantially improved pump efficiency, a low lasing threshold, and a high thermal stability. Pump laser wavelengths outside of the engineered spectral window lead to low pump efficiency due to strong absorption by the top DBR or inefficient excitation of pump-level excitons. The superiority of the absorption-free modified DBRs is demonstrated by simply switching the pump laser wavelength from 671 to 708 nm, which crosses the DBRs absorption edge and drastically reduces the lasing threshold by more than an order of magnitude from (363.5  ± 18.5) to (12.8  ± 0.3) μW.
Enhancement of the bandgap emission from GaN epilayer by surface plasmon resonance in the quadrupole oscillation mode using Ag nanoparticles protected by an oxide thin film
Authors: Kaito Seiya , Matsuyama Tetsuya , Wada Kenji , Funato Mitsuru , Kawakami Yoichi , Okamoto Koichi
Published: April 2023

Surface plasmons resonance is a promising way to improve the luminescence efficiency of light-emitting materials including InGaN/GaN-based quantum wells; however, it has rarely been used for GaN epilayer with metal nanoparticles (NPs). We demonstrated in enhancing the bandgap emission from GaN epilayer by localized surface plasmon resonance (LSPR) in a quadrupole oscillation mode using Ag NPs fabricated on the GaN. The shapes of the Ag NPs fabricated on the GaN substrates gradually changed over time and were eventually destroyed completely. This should be the reason why previous studies of enhancement of GaN-based materials by using Ag NPs have not performed as good results as expected. This problem was solved by employing oxide thin films to protect the Ag NPs from destruction or aggregation and obtain enhanced photoluminescence of the GaN epilayer. The localized and enhanced electric fields have been calculated by the finite difference time domain (FDTD) method to elucidate the enhancement mechanism. However, it has been still difficult to use this method to reproduce the enhanced emissions caused by the quantum interaction between the surface plasmons and excitons. We reproduced the highly efficient emissions attributed to the Purcell effect by evaluating the nanoantenna effect using the FDTD method. This technique confirmed that an oxide thin film between the GaN substrate and Ag NPs played an effective role in the local enhancement of the electromagnetic field and light extraction from the LSPR mode when several types of oxide thin films were considered.
Analysis of the transmission spectrum of the flat-cutoff sensors on wafers with metal layer
Authors: Yeom H. J. , Chae Gwang-Seok , Kim Jung Hyung , You ShinJae , Lee Hyo-Chang
Published: April 2023

A flat-cutoff sensor installed on the chamber wall or chuck allows precise measurement of the plasma density in real time, even with a wafer placed on the sensor. However, a few studies have been conducted on the measurement characteristics in an environment where a wafer containing a metal layer is placed on a sensor. In this study, we investigated the effect of wafers containing metal layers on flat-cutoff sensor measurements using circuit models and experiments. The metal layer in the wafer shifts the cutoff frequency up to four times higher, and the degree of shift depends on the plasma density. The relationship between the shift in the cutoff frequency and plasma density can be interpreted as the ratio of the plasma inductance to that of the metal layer from the circuit model of the flat-cutoff sensor. The calculation results were verified experimentally using wafers containing Al and Ti metal layers. As a result, measurement was found to be possible even when a wafer containing a metal layer was placed on a flat-cutoff sensor, and these results can improve the measurement accuracy of the flat-cutoff sensor for the real-time plasma measurement.
Wall-distance free transition model based on the laminar kinetic energy
Authors: Bulgarini D. , Ghidoni A. , Noventa G.
Published: April 2023

The next fluid dynamics solvers will be based on innovative numerical schemes and models to increase the fidelity and decrease the computational cost. The higher accuracy and geometrical flexibility guaranteed by discontinuous Galerkin spatial discretization methods in solving Reynolds-Averaged Navier–Stokes equations could represent an appealing solution in comparison with finite volume solvers for real-life simulations. In this context, numerical models able to accurately predict transitional flows are mandatory to overcome the limits of turbulence models and the costs of high-fidelity approaches, e.g., Direct Numerical Simulations and Large Eddy Simulations, for the efficient design of many industrial applications, e.g., aerospace, turbomachinery, maritime, automotive, and cooling applications. Among the transition models proposed in the literature, the local and phenomenological formulation seems to guarantee better robustness, fidelity, and easiness of implementation in all the solvers. All the transition models are based also on the wall-distance, to define some local terms or parameters and model the transition phenomenon. The calculation of the wall-distance can be critical in the discontinuous Galerkin framework for the high-order representation of the boundaries, which can become very expensive and high-memory consuming. To alleviate this problem, a wall-distance free version of a transition model based on the laminar kinetic energy is proposed and implemented in a high-order discontinuous Galerkin solver, and the robustness and fidelity are assessed by computing flows with bypass and separation-induced transition and different Reynolds number, turbulent intensity, and pressure gradient on flat plates. The wall-distance free formulation proves robustness and fidelity in all the cases, in comparison with the original formulation and an ad hoc modified formulation for the separation-induced transition cases.
Molecular p-doping induced dielectric constant increase of polythiophene films determined by impedance spectroscopy
Authors: Warren Ross , Blom Paul W. M. , Koch Norbert
Published: April 2023

The dielectric constant (εr) is a fundamental material parameter that governs charge transfer processes in organic semiconductors, yet its value is often assumed rather than measured. Here, we use impedance spectroscopy to determine εr in regioregular poly(3-hexylthiophen-2,5-diyl) (P3HT) thin films p-doped with the molecular dopants hexafluoro-tetracyanonaphthoquinodimethane and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ). We fit the impedance spectra using a single RC circuit model to determine the frequency-dependent capacitance and extract εr. The value of the dielectric constant increases by around two-thirds from 2.9 ± 0.1 (undoped polymer) to 4.9 ± 0.6 on the addition of one F4TCNQ molecule per 500 P3HT monomer units. In contrast, the addition of the weak dopant 7,7,8,8-tetracyanoquinodimethane (TCNQ), which does not undergo ground state charge transfer with P3HT, has no effect on the dielectric constant. Our results support the hypothesis that molecular doping has a considerable impact on the materials dielectric constant via polarizable host-dopant complexes.
Binuclear spin-crossover [Fe(bt)(NCS)2]2(bpm) complex: A study using first principles calculations
Authors: Lazaar Koussai , Aouaini Fatma , Gueddida Saber
Published: April 2023

The spin-crossover [Fe(bt)(NCS)2]2(bpm) complex is studied using spin-polarized density functional theory within the generalized gradient approximation, the Hubbard U and the weak van der Waals interactions in conjunction with the projector augmented wave method in its molecular and periodic arrangements. It is shown that the considered complex has three magnetic configurations [high spin state (HS)–HS, HS–low spin state (LS), and LS–LS] corresponding to those observed experimentally after two transition temperatures Tc(1) of 163 K and Tc(2) of 197 K. For the HS–HS magnetic state, we found that the two Fe centers are antiferromagnetically coupled for both molecular and periodic structures in good agreement with the experimental observations. Our results show that the computed total energy difference between the magnetic state configurations of the considered Fe2 complex is significantly smaller compared to those reported in the literature for other mono- or binuclear compounds.
Eccentricity-paced geomagnetic field and monsoon rainfall variations over the last 870 kyr
Authors: Zhou Weijian , Kong Xianghui , Paterson Greig A. , Sun Youbin , Wu Yubin , Ao Hong , Xian Feng , Du Yajuan , Tang Ling , Zhou Jie , Shi Zhengguo , Jull A. J. Timothy , Zhao Guoqing , An Zhisheng
Published: April 2023

Whether there are links between geomagnetic field and Earth’s orbital parameters remains unclear. Synchronous reconstructions of parallel long-term quantitative geomagnetic field and climate change records are rare. Here, we present
10
Be-derived changes of both geomagnetic field and Asian monsoon (AM) rainfall over the last 870 kyr from the Xifeng loess–paleosol sequence on the central Chinese Loess Plateau. The 
10
Be

GM

flux (a proxy for geomagnetic field-induced
10
Be production rate) reveals 13 consecutive geomagnetic excursions in the Brunhes chron, which are synchronized with the global records, providing key time markers for Chinese loess–paleosol sequences. The 
10
Be-derived rainfall exhibits distinct ~100 kyr glacial–interglacial cycles, and superimposed precessional (~23 kyr) cycles that match with those in Chinese speleothem δ
18
O record. We find that changes in the geomagnetic field and AM rainfall share a common ~100 kyr cyclicity, implying a likely eccentricity modulation of both the geomagnetic field and climate.
Reprogramming by drug-like molecules leads to regeneration of cochlear hair cell–like cells in adult mice
Authors: Quan Yi-Zhou , Wei Wei , Ergin Volkan , Rameshbabu Arun Prabhu , Huang Mingqian , Tian Chunjie , Saladi Srinivas Vinod , Indzhykulian Artur A. , Chen Zheng-Yi
Published: April 2023

Strategies to overcome irreversible cochlear hair cell (HC) damage and loss in mammals are of vital importance to hearing recovery in patients with permanent hearing loss. In mature mammalian cochlea, co-activation of
Myc
and
Notch1
reprograms supporting cells (SC) and promotes HC regeneration. Understanding of the underlying mechanisms may aid the development of a clinically relevant approach to achieve HC regeneration in the nontransgenic mature cochlea. By single-cell RNAseq, we show that MYC/NICD “rejuvenates” the adult mouse cochlea by activating multiple pathways including Wnt and cyclase activator of cyclic AMP (cAMP), whose blockade suppresses HC-like cell regeneration despite
Myc
/
Notch
activation. We screened and identified a combination (the cocktail) of drug-like molecules composing of small molecules and small interfering RNAs to activate the pathways of
Myc, Notch1, Wnt
and
cAMP.
We show that the cocktail effectively replaces
Myc
and
Notch1
transgenes and reprograms fully mature wild-type (WT) SCs for HC-like cells regeneration in vitro. Finally, we demonstrate the cocktail is capable of reprogramming adult cochlea for HC-like cells regeneration in WT mice with HC loss in vivo. Our study identifies a strategy by a clinically relevant approach to reprogram mature inner ear for HC-like cells regeneration, laying the foundation for hearing restoration by HC regeneration.
What can machine learning teach us about habit formation? Evidence from exercise and hygiene
Authors: Buyalskaya Anastasia , Ho Hung , Milkman Katherine L. , Li Xiaomin , Duckworth Angela L. , Camerer Colin
Published: April 2023

We apply a machine learning technique to characterize habit formation in two large panel data sets with objective measures of 1) gym attendance (over 12 million observations) and 2) hospital handwashing (over 40 million observations). Our Predicting Context Sensitivity (PCS) approach identifies context variables that best predict behavior for each individual. This approach also creates a time series of overall predictability for each individual. These time series predictability values are used to trace a habit formation curve for each individual, operationalizing the time of habit formation as the asymptotic limit of when behavior becomes highly predictable. Contrary to the popular belief in a “magic number” of days to develop a habit, we find that it typically takes months to form the habit of going to the gym but weeks to develop the habit of handwashing in the hospital. Furthermore, we find that gymgoers who are more predictable are less responsive to an intervention designed to promote more gym attendance, consistent with past experiments showing that habit formation generates insensitivity to reward devaluation.
Digitizing chemical discovery with a Bayesian explorer for interpreting reactivity data
Authors: M. Mehr S. Hessam , Caramelli Dario , Cronin Leroy
Published: April 2023

Interpreting the outcome of chemistry experiments consistently is slow and frequently introduces unwanted hidden bias. This difficulty limits the scale of collectable data and often leads to exclusion of negative results, which severely limits progress in the field. What is needed is a way to standardize the discovery process and accelerate the interpretation of high-dimensional data aided by the expert chemist’s intuition. We demonstrate a digital Oracle that interprets chemical reactivity using probability. By carrying out >500 reactions covering a large space and retaining both the positive and negative results, the Oracle was able to rediscover eight historically important reactions including the aldol condensation, Buchwald–Hartwig amination, Heck, Mannich, Sonogashira, Suzuki, Wittig, and Wittig–Horner reactions. This paradigm for decoding reactivity validates and formalizes the expert chemist’s experience and intuition, providing a quantitative criterion of discovery scalable to all available experimental data.
Human airway and nasal organoids reveal escalating replicative fitness of SARS-CoV-2 emerging variants
Authors: Li Cun , Huang Jingjing , Yu Yifei , Wan Zhixin , Chiu Man Chun , Liu Xiaojuan , Zhang Shuxin , Cai Jian-Piao , Chu Hin , Li Gang , Chan Jasper Fuk-Woo , To Kelvin Kai-Wang , Yang Zifeng , Jiang Shibo , Yuen Kwok-yung , Clevers Hans , Zhou Jie
Published: April 2023

The high transmissibility of SARS-CoV-2 Omicron subvariants was generally ascribed to immune escape. It remained unclear whether the emerging variants have gradually acquired replicative fitness in human respiratory epithelial cells. We sought to evaluate the replicative fitness of BA.5 and earlier variants in physiologically active respiratory organoids. BA.5 exhibited a dramatically increased replicative capacity and infectivity than B.1.1.529 and an ancestral strain wildtype (WT) in human nasal and airway organoids. BA.5 spike pseudovirus showed a significantly higher entry efficiency than that carrying WT or B.1.1.529 spike. Notably, we observed prominent syncytium formation in BA.5-infected nasal and airway organoids, albeit elusive in WT- and B.1.1.529-infected organoids. BA.5 spike-triggered syncytium formation was verified by lentiviral overexpression of spike in nasal organoids. Moreover, BA.5 replicated modestly in alveolar organoids, with a significantly lower titer than B.1.1.529 and WT. Collectively, the higher entry efficiency and fusogenic activity of BA.5 spike potentiated viral spread through syncytium formation in the human airway epithelium, leading to enhanced replicative fitness and immune evasion, whereas the attenuated replicative capacity of BA.5 in the alveolar organoids may account for its benign clinical manifestation.
The human malaria parasitePlasmodium falciparumcan sense environmental changes and respond by antigenic switching
Authors: Schneider Victoria M. , Visone Joseph E. , Harris Chantal T. , Florini Francesca , Hadjimichael Evi , Zhang Xu , Gross Mackensie R. , Rhee Kyu Y. , Ben Mamoun Choukri , Kafsack Björn F. C. , Deitsch Kirk W.
Published: April 2023

The primary antigenic and virulence determinant of the human malaria parasitePlasmodiumfalciparumis a variant surface protein called PfEMP1. Different forms of PfEMP1 are encoded by a multicopy gene family calledvar, and switching between active genes enables the parasites to evade the antibody response of their human hosts.vargene switching is key for the maintenance of chronic infections; however, what controls switching is unknown, although it has been suggested to occur at a constant frequency with little or no environmental influence.vargene transcription is controlled epigenetically through the activity of histone methyltransferases (HMTs). Studies in model systems have shown that metabolism and epigenetic control of gene expression are linked through the availability of intracellular S-adenosylmethionine (SAM), the principal methyl donor in biological methylation modifications, which can fluctuate based on nutrient availability. To determine whether environmental conditions and changes in metabolism can influencevargene expression,P.falciparumwas cultured in media with altered concentrations of nutrients involved in SAM metabolism. We found that conditions that influence lipid metabolism inducevargene switching, indicating that parasites can respond to changes in their environment by alteringvargene expression patterns. Genetic modifications that directly modified expression of the enzymes that control SAM levels similarly led to profound changes invargene expression, confirming that changes in SAM availability modulatevargene switching. These observations directly challenge the paradigm that antigenic variation inP. falciparumfollows an intrinsic, programed switching rate, which operates independently of any external stimuli.
Lysosomal chloride transporter CLH-6 protects lysosome membrane integrity via cathepsin activation
Authors: Zhang Qianqian , Li Yuan , Jian Youli , Li Meijiao , Wang Xiaochen
Published: April 2023

Lysosomal integrity is vital for cell homeostasis, but the underlying mechanisms are poorly understood. Here, we identify CLH-6, the C. elegans ortholog of the lysosomal Cl−/H+ antiporter ClC-7, as an important factor for protecting lysosomal integrity. Loss of CLH-6 affects lysosomal degradation, causing cargo accumulation and membrane rupture. Reducing cargo delivery or increasing CPL-1/cathepsin L or CPR-2/cathepsin B expression suppresses these lysosomal defects. Inactivation of CPL-1 or CPR-2, like CLH-6 inactivation, affects cargo digestion and causes lysosomal membrane rupture. Thus, loss of CLH-6 impairs cargo degradation, leading to membrane damage of lysosomes. In clh-6(lf) mutants, lysosomes are acidified as in wild type but contain lower chloride levels, and cathepsin B and L activities are significantly reduced. Cl− binds to CPL-1 and CPR-2 in vitro, and Cl− supplementation increases lysosomal cathepsin B and L activities. Altogether, these findings suggest that CLH-6 maintains the luminal chloride levels required for cathepsin activity, thus facilitating substrate digestion to protect lysosomal membrane integrity.
Stacking effect on the electronic structures of hexagonal GaTe
Authors: Lai Kang , Dai Jiayu
Published: April 2023

Employing first-principles density functional theory calculations with HSE06 hybrid functional, we investigate stacking-driven modifications on geometric and energy band structures of hexagonal GaTe (h-GaTe) with thickness ranging from bilayer to bulk. Our results show the most energetically favorable stacking order is AB′ type, regardless of the number of layers. The energy band structure of bulk h-GaTe exhibits indirect, quasi-direct and direct band gap for AA′, AB and AB′ stacking, respectively. In particular, as the thickness increases from single- to eleven-layers, both the conduction band minimum and valence band maximum are shifted to the

Γ
ˉ

point for AB′ stacking, leading to an indirect-to-direct band gap transition. Further analysis suggests the origin of the band gap transition can be attributed to the enhancement of interlayer coupling introduced by the stacking order.
Magnetic domain-dependent ultrafast optical demagnetization in stripe domain films
Authors: Chen Xiaowen , Adam Roman , Wang Fangzhou , Song Yawen , Pan Lining , Song Chengkun , Heidtfeld Sarah , Greb Christian , Li Qiuyue , Yu Jing , Zhang Jing , Cui Yuanzhi , Li Shandong , Xu Jie , Cinchetti Mirko , Schneider Claus M , Cao Derang
Published: April 2023

We investigated femto- and picosecond-time magnetization dynamics in a ferromagnetic Ni80Fe20 film with varying thicknesses (wedge-shaped film). We observed that the thickness gradient strongly affects the magnetic moment distribution, causing a magnetization reorientation from in-plane to out-of-plane, and formatting a stripe domain (SD) at the thicker end of the wedge. The magnetization dynamics measurements reveal that the part of the film displaying SDs follows a substantially faster demagnetization and magnetization recovery and smaller magnetization quenching compared to the in-plane domain film. The experiments and micromagnetic simulations support that the decrease in relaxation time is caused by a magnetic anisotropy of the films introduced by SD formation. Our results point out that the micromagnetic structure plays an important role in the magnetization dynamics in ferromagnetic films after optically triggered demagnetization.
Metal–insulator transition in composition-tuned nickel oxide films
Authors: Fowlie Jennifer , Georgescu Alexandru B , Suter Andreas , Mundet Bernat , Toulouse Constance , Jaouen Nicolas , Viret Michel , Domínguez Claribel , Gibert Marta , Salman Zaher , Prokscha Thomas , Alexander Duncan T L , Kreisel Jens , Georges Antoine , Millis Andrew J , Triscone Jean-Marc
Published: April 2023

Thin films of the solid solution Nd

1
−
x

La

x

NiO3 are grown in order to study the expected 0 K phase transitions at a specific composition. We experimentally map out the structural, electronic and magnetic properties as a function of x and a discontinuous, possibly first order, insulator–metal transition is observed at low temperature when x = 0.2. Raman spectroscopy and scanning transmission electron microscopy show that this is not associated with a correspondingly discontinuous global structural change. On the other hand, results from density functional theory (DFT) and combined DFT and dynamical mean field theory calculations produce a 0 K first order transition at around this composition. We further estimate the temperature-dependence of the transition from thermodynamic considerations and find that a discontinuous insulator–metal transition can be reproduced theoretically and implies a narrow insulator–metal phase coexistence with x. Finally, muon spin rotation (µSR) measurements suggest that there are non-static magnetic moments in the system that may be understood in the context of the first order nature of the 0 K transition and its associated phase coexistence regime.
A stress defect state measurement method based on low-frequency ACMFL excitation and Hall sensor array collection
Authors: Zhang ShaoXuan , Feng Jian , Lu Senxiang , Dong Xu , Zhang Xinbo
Published: April 2023

The safety testing of ferromagnetic materials, which are the main materials for various machines and equipment, is particularly important. Stress concentration zones (stress defects) cause stress corrosion of ferromagnetic materials, and also have the potential to cause direct damage to ferromagnetic materials. Estimation of stress sources state using electromagnetic nondestructive measurement methods is a critical and difficult problem. In this paper, a visual and intelligent identification method of stress defects in ferromagnetic materials by low frequency AC magnetic flux leakage (ACMFL) technique is proposed. A new three-point compression experiment was designed in this paper. Time-difference vision is established to analyze the ACMFL signal caused by stress defects. A visual transformed convolutional neural network deep learning algorithm has been proposed to identify grayscale patterns pre-processed by the time-difference vision. The results show that the method proposed in this paper elucidates the relationship between the time-difference vision of a stress defect and the stress source state of the mechanical stress. Our proposed method allows to analyze the pressure indenter size of the pressure source of stress defects.
Machine-readable data and metadata of international key comparisons in radionuclide metrology
Authors: Coulon Romain , Toro Federico Grasso , Michotte Carine
Published: April 2023

The digitalization of key comparisons in radionuclide metrology is being studied at the BIPM. Results of comparisons are made available on the BIPM KCDB platform where a PDF/A document can be downloaded. Access to the metadata contained in the PDF is not straightforward. Therefore, the XML and JSON versions of the report are now embedded in the PDF/A document, allowing direct access to the metadata. This achievement is a first step towards the implementation of FAIR (findable, accessible, interoperable, reusable) principles and does not affect the current policy of publishing comparison results. The combination of PDF/A and XML technologies seems to be an effective way to carry out digitalization. The strengths of both technologies can be brought together to meet the FAIR principles and ISO/IEC 17025 compliance. This approach benefits from robust data exchange features such as XML Schema and XML namespaces, as well as secure digital signatures and long-term archiving of PDF/A-3 documents.
Efficient non-fullerene organic solar cells employing aqueous solution-processed MoO3 as a hole-transporting layer
Authors: Li Yaozhao , Li Peng , Qu Minghao , Liu Feiyang , Wei Bin , Chen Guo
Published: April 2023

Organic solar cell (OSC) has drawn considerable interest in recent decades owing to their advantages of light weight, flexible, large area and potentially low-cost. Employing an appropriate hole-transporting layer (HTL) into an OSC device has been proved as an efficient method to obtain high efficiency OSC due to the enhancement of the hole transporting and extraction of the device. In this work, aqueous solution-processed MoO3 (s-MoO3) thin films were employed as HTLs to construct non-fullerene PM6:Y6 OSCs. The s-MoO3 thin film was prepared by using an aqueous solution process from an isopolymolybdate [NH4]6Mo7O24.4H2O precursor followed by thermal annealing treatment to convert the precursor to MoO3. The s-MoO3 HTL based PM6:Y6 device demonstrates a power conversion efficiency of 15.75%, which is 38% improved than that of the device with thermally evaporated-MoO3 as HTL and 8% improved than that of the device with PEDOT:PSS as HTL. The enhancement of the device performance could be attributed to the enhanced hole mobility and better band matching of the s-MoO3 HTL. Moreover, the s-MoO3 HTL based PM6:Y6 device exhibited higher device stability than those of the reference devices. Our finding indicates that this s-MoO3 film has great potential as efficient HTL for high performance non fullerene OSCs.
High detectivity solar blind photodetector based on mechanical exfoliated hexagonal boron nitride films
Authors: Qiu Mengting , Jia Zhenglin , Yang Mingyang , Nishimura Kazhihito , Lin Cheng-Te , Jiang Nan , Yuan Qilong
Published: April 2023

As an ultra-wide bandgap semiconductor, hexagonal boron nitride (h-BN) has drawn great attention in solar-blind photodetection owing to its wide bandgap and high thermal conductivity. In this work, a metal-semiconductor-metal structural two-dimensional h-BN photodetector was fabricated by using mechanically exfoliated h-BN flakes. The device achieved an ultra-low dark current (16.4 fA), high rejection ratio (R
205nm/R
280nm = 235) and high detectivity up to 1.28 × 1011 Jones at room temperature. Moreover, due to the wide bandgap and high thermal conductivity, the h-BN photodetector showed good thermal stability up to 300 °C, which is hard to realize for common semiconductor materials. The high detectivity and thermal stability of h-BN photodetector in this work showed the potential applications of h-BN photodetectors working in solar-blind region at high temperature.
Electrical performance of monolayer MoS2 transistor with MoS2 nanobelt metallic edges as electrodes
Authors: Yang Lei , Yuan Xueqin , Shen Lirui , Liu Renyong , Wu Ju , Zhang Jiajia
Published: April 2023

The contact electrodes have great influence on the performance of monolayer MoS2 devices. In this paper, monolayer MoS2 and MoS2 nanobelts were synthesized on SiO2/Si substrates via the chemical vapor deposition method. By using wet and dry transfer process, MoS2 nanobelt metallic edges were designed as the source/drain contact electrodes of monolayer MoS2 field effect transistor. The ‘nanobelt metallic edges’ refers to the top surface of the nanobelt being metallic. Because the base planes of MoS2 nanobelt vertically stand on the substrate, which makes the layer edges form the top surface of the nanobelt. The nonlinear I
ds–V
ds characteristics of the device indicates that the contact between the monolayer MoS2 and MoS2 metallic edges displays a Schottky-like behavior. The back-gated transfer characteristics indicate that monolayer MoS2 device with MoS2 nanobelt metallic edges as electrodes shows an n-type behavior with a mobility of ∼0.44 cm2 V−1·s−1, a carrier concentration of ∼7.31 × 1011 cm−2, and an on/off ratio of ∼103. The results enrich the electrode materials of two-dimensional material devices and exhibit potential for future application of MoS2 metallic edges in electronic devices.
Circularly polarized attosecond pulses generation from laser interaction with magnetized sub-critical plasmas
Authors: Pan Chenhao , Wang Jingwei , Luan Shixia , Zhao Yao , Leng Yuxin , Li Ruxin
Published: April 2023

We propose a method to generate circularly polarized (CP) attosecond pulses by the interactions of a relativistic-intensity right-hand CP laser pulse and magnetized sub-critical plasma. It is theoretically and numerically demonstrated that when an external magnetic field with an appropriate strength is applied to a sub-critical plasma along the laser propagation, the ponderomotive force of a right-hand CP laser at the vacuum-plasma boundary is significantly enhanced. The electrons are then steadily pushed forward until the timely-increasing charge separation field becomes strong enough to pull them back, forming a dense and counter-moving electron sheet. The relativistic-velocity electron sheet works as a flying mirror to compress the tail of the driving laser and efficiently generate a single CP attosecond pulse. The present scheme shows a stable efficiency on different scale lengths of preplasma and thus may provide a robust way to generate bright and CP attosecond pulses.
The performance of equilibrium radial electric field shear on microturbulence with different magnetic shears in tokamak plasmas
Authors: Chen Y C , Qin Y Q , Sun G Y , Lin Z
Published: April 2023

Global gyrokinetic particle simulations show that equilibrium radial electric field (E

r
) shear reduces the linear growth rate, ion heat conductivity, and nonlinear turbulence amplitude for both the ion temperature gradient (ITG) and kinetic ballooning mode (KBM) microturbulence by tilting the poloidal mode structure. The increase in the magnetic shear enhances the stabilizing performance of the E

r
shear on linear growth rate for the ITG case but has no effect on that for the KBM case. The radial correlation length of the ITG turbulence is decreased by increasing the magnetic shear in a weak ion diamagnetic flow shear condition with low β, leading to a reduction in the effective E × B shearing rate, which weakens the suppression performance of the E

r
shear on the ITG turbulence amplitude. In contrast, under a larger ion diamagnetic shear flow for higher β, an increase in magnetic shear strengthens the suppression performance of the E

r
shear on the KBM turbulence amplitude due to an increase in the effective shearing rate by increasing the radial correlation length of the turbulence.
Current crowding in deep ultraviolet light-emitting diodes with fish-bone shaped p-electrode by microscopic emission investigation
Authors: Chen Li , Chen Qiushuang , Chen Cong , Xu Houqiang , Peng Xianchun , Yan Long , Hu Jianzheng , Guo Shiping , Guo Wei , Ye Jichun
Published: April 2023

Current crowding is the main bottleneck preventing the prosperity of AlGaN-based deep-ultraviolet light-emitting-diodes (DUV-LEDs) considering the low electrical conductivity of p-type contact layer. A deeper understanding of the current distribution in p-AlGaN is critical, which enables the rational design of advanced device architectures. In this work, a fish-bone-shaped p-type electrode was deposited on top of a 280 nm AlGaN DUV-LED for investigation of localized emissions. A significantly raised junction temperature was identified, causing efficiency droop in DUV-LEDs under relatively low injection current with fish-bone-shaped p-type electrodes. High junction temperature is attributed to the significantly high localized current density which is confirmed by the spatial-resolved electroluminescence spectra and theoretical simulation. The crowding current level beneath the p-electrodes is estimated to be several times higher than that in between the electrodes.
The development and applications of nanoporous gallium nitride in optoelectronics: a review
Authors: Yao Yuxuan , Liang Yue , Guo Jiabao , Xiu Huixin
Published: April 2023

The development of nanoporous gallium nitride (NP-GaN) has widened the material properties and applications in third-generation semiconductor areas. NP-GaN has been used in laser emitters, light-emitting diodes, optical sensors, and optical energy storage devices. In this paper, we reviewed the most recent progress in the NP-GaN field by electrochemical etching. The etched GaN has many superior properties compared with original GaN templates, such as stronger photoluminescence intensity, thermal conductivity, piezo-electricity, more accessible area, stress relief, and refractive index. These advantages will make GaN more widely used in the field of optics and optoelectronics. Pore formation can be controlled by adjusting the applied potential and etching time. The NP-GaN makes the material of GaN have broader application prospects. We introduced in detail the application prospects of different GaN based processes and subsequent application methods in optoelectronics, sensors, and materials themselves. This review will help to improve further development of NP-GaN applications.
Development of an electrorheological elastomer isolator working in shear-squeeze mixed mode
Authors: Niu Chenguang , Dong Xufeng , Xiong Xiaoyan , Ren Junqi , Niu Linkai , Li Congming , Zhang Dongguang , Guo Jibao
Published: April 2023

The vibrating screen equipment will resonate through the resonance region during startup and shutdown stage. However, the stiffness and damping of the traditional passive vibration isolator cannot be adjusted in use, which leads to the unsatisfactory vibration isolation effect of that on the installation foundation of vibrating screen. In this paper, based on the characteristics of electrorheological elastomer (ERE) with tunable storage modulus, a variable stiffness ERE isolator in shear-squeeze mixed mode is developed. At the first step, the EREs used for the isolator was prepared, and the dynamic viscoelastic properties were measured. After that, the structure of ERE isolator was designed, and the vibration isolation effect of the ERE isolator for vibrating screen was analyzed by simulation. The simulation results demonstrate the resonance amplitude and stopping time of the vibrating screen in startup and shutdown stage will decrease with the ascending electric field strength. Finally, the shear-squeeze mixed-mode ERE isolator was tested on electro-dynamic shaker. The experimental results indicate that the ERE isolator has a better effect of vibration reduction with increased electric field strength in startup and shutdown stage of vibrating screen, and the acceleration transmissibility by ERE isolator is reduced 37.6% under 3 kV mm−1.
Compact and sturdy orbital angular momentum sorter without destroying photon states
Authors: Zhang Jingfeng , Kong Ling-Jun , Zhang Zhuo , Zhang Furong , Zhang Xiangdong
Published: April 2023

The orbital angular momentum (OAM) has been widely studied and applied to many scientific fields, especially in optical communication and quantum information. In order to give full play to the high-dimensional characteristics of OAM, separating different OAM states is a fundamental requirement. Here we find a way to introduce the mode dependent phase shift by using Porro prism, design and manufacture a new kind of two-output OAM sorter. Our OAM sorter can separate two OAM states with different topological charges without destroying them. Because it is composed of several linear commonly optical elements, which can be closely pasted together, our OAM sorter is very compact and sturdy. Furthermore, by means of cascading, our design can be used for constructing an OAM sorter with multiple output ports. Therefore, our research should have great potential application prospects, especially in the communication protocol based on OAM.
A new life for Apollo’s photos
Authors: Glester Andrew
Published: April 2023

Andrew Glester reviews Apollo Remastered by Andy Saunders.
Natural quasicrystal found in ‘fossilized lightning’
Authors: Jarman Sam
Published: April 2023

A quasicrystal that was probably formed by a strong electrical discharge through a sand dune has been found by researchers in the US and Italy.
Wind energy could power human habitations on Mars
Authors: James Chaneil
Published: April 2023

A study has used climate models of Mars to calculate the short-term and seasonal variability of wind power that would be generated by turbines on the red planet.
UK creates ‘high-risk, high reward’ research funding agency
Authors: Randall Ian
Published: April 2023

The Advanced Research and Invention Agency has been created in the UK with the goal of “identifying and funding revolutionary science and technology at speed from world-class scientists”.
NIST labs are ‘deficient’, says report
Authors: Gwynne Peter
Published: April 2023

A report by the US National Academies of Sciences, Engineering, and Medicine has found that facilities belonging to the National Institute of Standards and Technology do not meet acceptable standards for building conditions.
Europe is at the forefront of quantum-based technologies
Authors: Boerkamp Martijn
Published: April 2023

Europe is leading the race to implement quantum-based technologies, according to a new report from the European Commission.
Science elevated to cabinet position in government
Authors: Allen Michael
Published: April 2023

Science has been elevated to a cabinet-level position in the UK government for the first time in decades with the creation of a new Department for Science, Innovation and Technology.
Doomsday clock edges closer to midnight
Authors: Banks Michael
Published: April 2023

The science and security board of the Bulletin of the Atomic Scientists has moved the Doomsday Clock forward by 10 seconds to 90 seconds to midnight – the first change since 2019.
PhD blues
Authors: Durrani Matin
Published: April 2023

Today’s PhD students face unprecedented challenges but lack enough support.
Who killed General Electric?
Authors: Chandran Anita
Published: April 2023

Anita Chandran reviews Power Failure: the Rise and Fall of General Electric by William D Cohan.
Guiding next-generation astronomers
Authors: Lea Rob
Published: April 2023

Wen-fai Fong, assistant professor in physics and astronomy and head of Northwestern University’s Fong group, talks to Rob Lea about her journey into physics and mentoring the scientists of the future during one of astronomy’s most exciting eras.
Establishing Pediatric Reference Ranges for Rotational Thromboelastometry
Authors: Goodhue Meyer Erin Kathleen , Uffman Joshua , Townsend Stephanie , Rice-Weimer Julie , Tobias Joseph , Nicol Kathleen
Published: April 2023

Objectives

The aim of our investigation was to establish normal pediatric reference intervals (PRIs) for rotational thromboelastometry (ROTEM) Delta assays in a representative group of healthy children, 0 to 18 years of age, at our institution.

Methods

This was a prospective study of healthy pediatric patients undergoing elective minor surgery requiring placement of an intravenous cannula. The sample size for patients was 20 per age group of either sex from 5 different age groups based on coagulation system maturity: 0 to 6 or fewer months, more than 6 to 12 or fewer months, more than 1 year to 5 or fewer years, more than 5 to 11 or fewer years, and more than 11 to 18 or fewer years. ROTEM Delta assays assessed include the EXTEM, INTEM, and FIBTEM.

Results

We defined 2 sets of ROTEM PRIs for our patient population: one for patients 11 years or younger and one for children more than 11 years of age. For those 11 years or younger, the PRIs were derived from the 2.5th and 97.5th percentiles from the 0 to 11 age groups. For those older than 11 years, previously published adult reference intervals validated internally with adult normal samples were used.

Conclusions

The 2 sets of PRIs were embedded into our electronic medical record, allowing clinicians to easily interpret their patient’s ROTEM results against age-verified reference ranges, enabling them to make informed transfusion decisions.