bluuebunny/crossref_metadata_2025 huggingface dataset:
Introduction to the RSC Advances Emerging Investigators series 2021
Authors: Batteas James
Published: August 2022

RSC Advances is proud to present the 2021 Emerging Investigators series. Guest Edited by Professor James Batteas (Texas A&M University), this series showcases some of the very best work from chemists in the early stages of their independent careers.
Unprecedented pairs of uranium (iv/v) hydroxido and (iv/v/vi) oxido complexes supported by a seven-coordinate cyclen-anchored tris-aryloxide ligand
Authors: Löffler Sascha T. , Hümmer Julian , Scheurer Andreas , Heinemann Frank W. , Meyer Karsten
Published: August 2022

Employing the newly developed, hepta-dentate tris(aryloxide) ligand cyclen(Me)(t-Bu,t-BuArOH)3 provides controlled access to the first U(iv/v) hydroxido and U(iv/v/vi) oxido complex pairs in a retained ligand environment.
Radical defects modulate the photocatalytic response in 2D-graphitic carbon nitride
Authors: Raciti Edoardo , Gali Sai Manoj , Melchionna Michele , Filippini Giacomo , Actis Arianna , Chiesa Mario , Bevilacqua Manuela , Fornasiero Paolo , Prato Maurizio , Beljonne David , Lazzaroni Roberto
Published: August 2022

The nature of radical defects governs the photocatalytic activity of graphitic carbon nitride.
Integrated temperature and pressure dual-mode sensors based on elastic PDMS foams decorated with thermoelectric PEDOT:PSS and carbon nanotubes for human energy harvesting and electronic-skin
Authors: Gao Fu-Lin , Min Peng , Gao Xuan-Zhi , Li Changjun , Zhang Tingting , Yu Zhong-Zhen , Li Xiaofeng
Published: August 2022

A temperature and pressure dual-mode sensor is fabricated by coating thermoelectric PEDOT:PSS/CNT on PDA-modified PDMS foams for human heat harvesting and E-skin. It can measure temperature and pressure changes without complex decoupling processes.
Pressure-induced non-radiative losses in halide perovskite light-emitting diodes
Authors: Jung Young-Kwang , Abdulla Mayami , Friend Richard H. , Stranks Samuel D. , Walsh Aron
Published: August 2022

When halide perovskite light-emitting diodes are compressed, the electroluminesence weakens, which is explained by an increase in defect populations.
Lead-free perovskite Rb2Sn1−xTexCl6 with bright luminescence for optical thermometry and tunable white light emitting diodes
Authors: Gong Shunfa , Wu Ruirui , Han Qiuju , Kong Degui , Wu Wenzhi
Published: August 2022

Te4+-doped Rb2SnCl6 MCs are prepared by the solvothermal method, which have strong and broad emission. The long fluorescence lifetime and high PLQY make it have good application prospect in optical thermometry and white LED.
Multiple resonance thermally activated delayed fluorescence enhanced by halogen atoms
Authors: Lee Youngnam , Hong Jong-In
Published: August 2022

Halogenated multiple resonance thermally activated delayed fluorescence (MR-TADF) emitters, Cl-MR and Br-MR, were developed to improve the reverse intersystem crossing rate constant of MR-TADF emitters.
Regulating the coordination environment of a metal–organic framework for an efficient electrocatalytic oxygen evolution reaction
Authors: Lv Enjun , Yong Jiayi , Wen Jinguli , Song Zhirong , Liu Yi , Khan Usman , Gao Junkuo
Published: August 2022

A novel metal–organic framework (MOF) with efficient OER electrocatalytic performance (defined as FeCo-L1L2) was successfully synthesized.
Two-pore channels: going with the flows
Authors: Morgan Anthony J. , Martucci Lora L. , Davis Lianne C. , Galione Antony
Published: August 2022

In recent years, our understanding of the structure, mechanisms and functions of the endo-lysosomal TPC (two-pore channel) family have grown apace. Gated by the second messengers, NAADP and PI(3,5)P2, TPCs are an integral part of fundamental signal-transduction pathways, but their array and plasticity of cation conductances (Na+, Ca2+, H+) allow them to variously signal electrically, osmotically or chemically. Their relative tissue- and organelle-selective distribution, together with agonist-selective ion permeabilities provides a rich palette from which extracellular stimuli can choose. TPCs are emerging as mediators of immunity, cancer, metabolism, viral infectivity and neurodegeneration as this short review attests.
Unveiling the mechanisms and biosynthesis of a novel nickel-pincer enzyme
Authors: Chatterjee Shramana , Gatreddi Santhosh , Gupta Swati , Nevarez Jorge L. , Rankin Joel A. , Turmo Aiko , Hu Jian , Hausinger Robert P.
Published: August 2022

The nickel-pincer nucleotide (NPN) coenzyme, a substituted pyridinium mononucleotide that tri-coordinates nickel, was first identified covalently attached to a lysine residue in the LarA protein of lactate racemase. Starting from nicotinic acid adenine dinucleotide, LarB carboxylates C5 of the pyridinium ring and hydrolyzes the phosphoanhydride, LarE converts the C3 and C5 carboxylates to thiocarboxylates, and LarC incorporates nickel to form a C–Ni and two S–Ni bonds, during the biosynthesis of this cofactor. LarB uses a novel carboxylation mechanism involving the transient formation of a cysteinyl-pyridinium adduct. Depending on the source of the enzyme, LarEs either catalyze a sacrificial sulfur transfer from a cysteinyl side chain resulting in the formation of dehydroalanine or they utilize a [4Fe–4S] cluster bound by three cysteine residues to accept and transfer a non-core sulfide atom. LarC is a CTP-dependent enzyme that cytidinylylates its substrate, adds nickel, then hydrolyzes the product to release NPN and CMP. Homologs of the four lar genes are widely distributed in microorganisms, with some species containing multiple copies of larA whereas others lack this gene, consistent with the cofactor serving other functions. Several LarA-like proteins were shown to catalyze racemase or epimerase activities using 2-hydroxyacid substrates other than lactic acid. Thus, lactate racemase is the founding member of a large family of NPN-containing enzymes.
2‐D analytical magnetic model for optimal design of an outer rotor permanent magnet synchronous machine
Authors: Vahaj Amir Abbas , Rahideh Akbar , Zamani Faradonbeh Vahid , Salehi Ali Reza , Ghaffari Alireza , Shahnazari Mostafa , Lubin Thierry
Published: August 2022

The objective of this paper is to investigate the optimal design of a 120 W outer‐rotor permanent magnet synchronous machine for air‐conditioning applications to reduce the electricity consumption and machine costs. To this end, a 2‐D analytical magnetic model, combined with a teaching–learning based optimisation algorithm is employed. The objectives are to simultaneously maximise the machine efficiency and minimise the material cost. Constraints such as the required output torque, predefined machine volume, maximum allowable torque ripple and unbalanced magnetic force and limitations to avoid iron core magnetic saturation are imposed simultaneously. To find the flux density in iron parts, a new method based on the subdomain technique has been presented. To evaluate the analytical model in terms of accuracy and speed, the results of the 2‐D analytical approach are compared with those of the 2‐D and 3‐D linear/non‐linear finite element method. Finally, a prototype of the optimised machine is fabricated and the superiority of the presented approach is demonstrated.
Constant modulus shaped beam synthesis via linear fractional semidefinite relaxation
Authors: Dou Xiuquan , Hu Mengkai , Liu Qifan
Published: August 2022

Excitation amplitude control is a critical issue regarding the shaped beam synthesis of array antennas. Ideally, excitations can have the same amplitude, and the desired beam can be achieved only by changing the phases. This method is called constant modulus synthesis, which can reduce the complexity of array antennas and is more conducive to the feeding, but it is really difficult to realize. In this paper, the authors derive a novel constant modulus beam synthesis algorithm, which uses the linear fractional semidefinite relaxation to relax the constant modulus constraints. Simulation results show that this method is stable and can maintain the excitation modulus while realizing the shaped beam.
The combined effect of inorganic salt and ionic liquid in pretreatment on enzymatic saccharification of rice straw
Authors: Jose Diana , Raina Neelu , Deepakkumar Rajagopal , Panakkal Elizabeth Jayex , Sriariyanun Malinee , Kangsadan Tawiwan
Published: August 2022

The pretreatment method is one of the challenging steps in the production of biofuel through the biorefinery process that unlocks the recalcitrant nature of lignocellulosic biomass. Ionic liquid pretreatment gained attention for being highly effective to improve the enzymatic saccharification of the biomass, however its high cost hinders its industrial application. In this study, the combined effect of ionic liquid 1- ethyl-3-methylimidazolium acetate (EMIM-Ac) with inorganic salts (NaCl and KCl) was used for the pretreatment of rice straw. Optimization of pretreatment was conducted based on Response Surface Methodology and sugar yields obtained by EMIM-Ac+NaCl (160 °C, 88.7 min, 7.6%wt) and EMIMAc+ KCl (160 °C, 68.2 min, 12.5%wt) were 670.7 and 392.9 mg/g-biomass, respectively. The effect of combined pretreatment on ethanol production was analyzed after 48h fermentation. The results showed that the ethanol yield from pretreated samples with EMIM-Ac+NaCl (0.72%) and EMIM+KCl (0.76%) was increased by 2.18 and 2.25 fold times, respectively, compared to untreated sample (0.33%). This combined effect of inorganic salts and ionic liquid significantly removed the lignin during pretreatment, while maintaining efficient enzymatic saccharification of rice straw. Thus, this cost-effective combined chemical method may be an alternative strategy for increasing cellulosic ethanol production.
A comparative study of the anticorrosive response ofTinospora cordifoliastem extract for Al and Cu in biodiesel-based fuels
Authors: Amgain Kumar , Subedi Bhesh Nath , Joshi Susan , Bhattarai Jagadeesh
Published: August 2022

The anticorrosive effect of methanol extract ofTinospora cordifoliastem for Al and Cu metals in pure biodiesel and its 10% blend with petrodiesel was investigated at 25±2 °C in a closed system by corrosion, inhibition efficiency, adsorption, and electrochemical tests. The corrosion inhibiting action of the plant extract for Cu in the biodiesel was more efficient than in the blend, while the extract showed more anticorrosive behavior of Al metal in the blend than in the biodiesel. Adsorption of the plant extract on the metal surface conformed to the Langmuir adsorption model. The plant extract functioned as a mixed-type corrosion inhibitor for both the metals in both biodiesel and its blend based on the experimental results. Outcomes of the study confirm the suggestive evidence to formulate the green extract-based biodiesel additives to enhance the anti-corrosive response for the Al and Cu metal parts of the vehicle engine. Nepal-originTinospora cordifoliastem extract could be used as an anticorrosive agent to control the corrosion of Al and Cu metals in biodiesel-based fuels.
Influence of extraction times on physical and functional properties of gelatin from salted jellyfish by-products
Authors: Charoenchokpanich Wiriya , Muangrod Pratchaya , Roytrakul Sittiruk , Rungsardthong Vilai , Vatanyoopaisarn Savitri , Wonganu Benjamaporn , Thumthanaruk Benjawan
Published: August 2022

By-products of the marine industry have gained attention for producing valuable food ingredients like gelatin, which might benefit food applications and decrease food waste. Gelatin is the only protein-based food hydrocolloid, mainly used for gelling, viscosity, or emulsifying in the food industry. So far, a number of researchers have reported that by-products of salted jellyfish can produce jellyfish gelatin. The quality of jellyfish gelatin gel depends on several factors including hydrochloric acid pretreatment, extraction temperature, and extraction time. However, the functional properties such as foaming and emulsifying of jellyfish gelatin are not well understood. This research was aimed at investigating the hydrochloric acid pretreatment effect of extraction times (12, 24, and 48 h) at 60 °C on the resulting gelatin's yield, physical, and functional properties. Results showed that jellyfish gelatin's yield, gel strength, and viscosity significantly increased with increasing extraction times. Jellyfish gelatin yields were 2.74-14.07%. The gel strength of jellyfish gelatin extracted for 48 h (325.97±2.84 g) was higher than that of jellyfish gelatins extracted for 12 h (210.46±3.97 g) and 24 h (261.60±3.25 g). All jellyfish gelatins can form gels at 4 °C. Viscosity values of jellyfish gelatin were 23.00-24.50 centipoise. The foaming capacity and foaming stability of jellyfish gelatin were 12.28-17.54% and 10.52-15.78%, respectively. The emulsification activity index of jellyfish gelatin was 13.11-13.30 m2/g, and the emulsification stability index was 39.19-56.42%. As a result, varied gelatin extraction periods influenced jellyfish gelatin's physical and functional properties, indicating that the extended extraction time of 48 h delivered the jellyfish gelatin that can be used as a foaming and emulsifying agent. Therefore, turning the jellyfish by-products into food ingredients like gelatin would increase product values and potential uses in the food and medical applications.
Gracefulness of Two Kinds of Unconnected Graphs with Even Vertices
Authors: WEN Xiaoyan , WANG Tao , SUI Lili
Published: August 2022

Two kinds of unconnected double fan graphs with even vertices,[see formula in PDF] and [see formula in PDF]
[see formula in PDF] were presented. For natural number [see formula in PDF],[see formula in PDF],the two graphs are all graceful graphs, where [see formula in PDF] are even-vertices path,[see formula in PDF] is odd-vertices path,[see formula in PDF] are the complement of graph [see formula in PDF],[see formula in PDF] is the join graph of [see formula in PDF] and [see formula in PDF].
On Entire Solutions of Two Certain Types of Non-Linear Differential-Difference Equations
Authors: LI Jingjing , HUANG Zhigang
Published: August 2022

In this paper, we mainly investigate entire solutions of the following two non-linear differential-difference equations [see formula in PDF] and [see formula in PDF]
[see formula in PDF], where [see formula in PDF] is an integer, [see formula in PDF] are non-zero constants, [see formula in PDF] is a non-vanishing polynomial and [see formula in PDF] is a non-constant polynomial. Under some additional hypotheses, we analyze the existence and expressions of transcendental entire solutions of the above equations.
Modeling the modulation characteristics of the Bradbury–Nielsen gate in ion mobility spectrometers
Authors: Guo Kaitai , Zhang Chong , Ni Kai , Wang Xiaohao
Published: August 2022

The Bradbury–Nelson gate (BNG) is a common device used for ion control in time-of-flight mass spectrometry and ion mobility spectrometry (IMS). A dual-location control model was employed in order to better understand the behavior of ions around a modulated BNG. This model illustrated that the ions are released from the starting location and truncated at the cutoff location. The shapes of the starting and cutoff locations are both curved with similar curvature, and the cutoff location is situated further back. Therefore, the distance between the two locations is a key parameter leading to the ion loss during modulation and is influenced by the gating voltage difference. Through simulations and experiments, the ion loss is verified to increase with the increase in the gating voltage difference. Taking a Fourier transform IMS as an example, by reducing the gating voltage difference from 150 to 50 V, the signal-to-noise ratio of the time domain result was improved from 91.7 to 386.5 and the resolving power was improved from 40.9 to 63.6. In addition, the superposition effect of multicycle modulation is shown and explained by the model. When the modulated frequency is too rapid and the closing time is insufficient for all the ions to be consumed, some ions continue to exist between the two locations, and the residual ions then enter the drift region during the next few cycles. This phenomenon needs to be avoided because the total number of ions entering the drift region will then increase uncontrollably.
Transient optically induced grating and underlying transport process in bent-core nematics
Authors: Hao Luguo , Jing Hongzhen , Xiang Ying , Iljin Andrey , Wang Yao , Li Hao , Li Qinyuan , Peng Jinghui , Kohout Michal
Published: August 2022

In this paper, we have applied a holographic time-of-flight technique with a nanosecond laser pulse to perform time-resolved measurements of optically induced gratings in bent-core nematics formed by a new kind of liquid crystal (LC). The effects of the electric field, laser pulse energy, temperature, and light intensity pattern on the photocharge transport process were investigated systematically. The results indicate that some peculiar features, such as high photosensitivity, relatively large mobility, and negative conductivity anisotropy, were present in the studied soft-matter system. Furthermore, a coupling between the optically induced grating and electrically induced convection was observed, which revealed a competitive state between them via the transport process. Thus, a better understanding of the carrier transport process involving photosensitivity and response time will help to tailor LC devices toward novel optical applications.
Single and coupled Helmholtz resonators for low frequency sound manipulation
Authors: Sabat R. , Pennec Y. , Lévêque G. , Torrent D. , Ding C. , Djafari-Rouhani B.
Published: August 2022

In this work, we use the finite element method to study the acoustic properties of single and coupled Helmholtz resonators (HRs). Each HR consists of a sphere drilled with one or several small openings. For a single HR, we show that the total pressure computed at the opening's edge as a function of frequency reveals the presence of a local dip in addition to the well-known resonance peak. In the case of coupled resonators, we highlight two resonance peaks at low frequencies, arising from excitation of a monopolar breathing mode, for which the twin resonators are in phase (S-peak), and a dipolar mode, where the two spheres resonate out of phase (AS-peak). In the near field, we study the influence of the number of apertures, the distance between spheres and their orientation on the frequencies, and quality factors of the two resonances. In the far field, we show that the propagation of the scattered wave is quasi-isotropic for the S-peak, while it leads to a dipolar-type pressure distribution for the AS-peak, with a directionality depending on the relative orientation of the openings in adjacent HRs. By increasing the number of coupled HRs from two to four units, we investigate the effect of additional mode coupling. Accordingly, the present study aims to manipulate the sound at targeted frequencies, by varying the distance or orientation between twin resonators, and to discuss the effect of dissipation. The demonstration of the coupling between sub-wavelength units opens the way to multi-frequency functionalities of acoustic metasurfaces.
Experimental results from x-ray imaging crystal spectrometer utilizing double crystal assembly in Korea Superconducting Tokamak Advanced Research (KSTAR)
Authors: Lee S. G. ,   KSTAR Team
Published: August 2022

A double crystal assembly (DCA) for multiple atomic spectra measurements, including helium-like Ar and hydrogen-like Ar, and other impurity lines are applied for the x-ray imaging crystal spectrometer in Korea Superconducting Tokamak Advanced Research. The DCA expands measurable wavelengths much wider so that cross comparisons of the ion temperature and toroidal rotation between two different atomic states are possible. The recent experimental comparison studies for the ion temperature and toroidal rotation of helium-like Ar and hydrogen-like Ar from the DCA are reported.
High-capacity hydrogen storage in yttrium-decorated Ψ-graphene: Acumen from density functional theory
Authors: Chakraborty Brahmananda , Vaidyanathan Antara , Kandasamy Manikandan , Wagh Vaibhav , Sahu Sridhar
Published: August 2022

Employing density functional theory simulations, we have predicted Y-decorated Ψ-graphene as a potential hydrogen storage material for fuel cell vehicle (FCV) applications. The system is stable at ambient and higher temperatures as substantiated by ab initio molecular dynamics simulations and is capable of holding 8.31 wt. % of hydrogen, higher than the U.S. Department of Energy (DOE) target. Each Y atom attached on Ψ-graphene can adsorb seven H2 molecules with a mean binding energy of −0.39 eV per H2 and a desorption temperature of 496.55 K—highly suitable for fuel cell applications. The Y atom binds strongly with the Ψ-graphene sheet, evident from the binding energy of −3.06 eV. The presence of a diffusion energy barrier of 0.4–0.7 eV for the diffusion of Y atom across Ψ-graphene may prevent metal–metal clustering. The flow of charge is found to be from Y atom 4d orbitals toward the C 2p orbitals of Ψ-graphene. Hydrogen molecules are found to bind reversibly by Kubas interactions involving charge donation and back donation between Y atom 4d orbitals and 1s orbitals of hydrogen, allowing for a suitable binding energy for FCV applications. Considering the stability of the system, optimum binding energy, and desorption temperature as per U.S. DOE targets; adequate barrier energy for diffusion; and excellent gravimetric hydrogen storage capability of the material, we propose Y-decorated Ψ-graphene as a potent hydrogen storage material for FCV applications.
Absolute calibration of the conical crystal configuration of the zinc spectrometer (ZSPEC) at the OMEGA laser facility
Authors: Cordova T. , MacDonald M. J. , Döppner T. , Beg F. N. , Dozieres M. , Kozioziemski B. , Pablant N. A. , Sorce C. M. , Whiting N. G.
Published: August 2022

In this study, we present the absolute calibration of the conical crystal for the zinc spectrometer (ZSPEC), an x-ray spectrometer at the OMEGA laser facility at the Laboratory for Laser Energetics. The ZSPEC was originally designed to measure x-ray Thomson scattering using flat or cylindrically curved highly oriented pyrolytic graphite crystals centered around Zn He-alpha emission at 9 keV. To improve the useful spectral range and collection efficiency of the ZSPEC, a conical highly annealed pyrolytic graphite crystal was fabricated for the ZSPEC. The conically bent crystal in the Hall geometry produces a line focus perpendicular to the spectrometer axis, corresponding to the detector plane of electronic detectors at large scale laser facilities such as OMEGA, extending the useful range of the spectrometer to 7–11 keV. Using data collected using a microfocus Mo x-ray source, we determine important characteristics of ZSPEC such as the dispersion, spatial resolution, and absolute sensitivity of the instrument. A ray-trace model of ZSPEC provides another point of agreement in calculations of the ZSPEC dispersion and crystal response.
Breakup of a laminar liquid jet by coaxial non-swirling and swirling air streams
Authors: Liang Yifan , Johansen Lars Christian , Linne Mark
Published: August 2022

This paper describes an experimental study on shear-based spray formation. A laminar liquid jet was ejected inside co-annular non-swirling and swirling air streams. The aerodynamic Weber numbers (WeA) and swirl numbers (S) of the flow cases ranged from 4 to 1426 and from 0 to 3.9, respectively. High-speed shadowgraphy was utilized to obtain data on the first droplet locations, breakup lengths of the liquid jets, and two-dimensional wave spatiotemporal spectra for the jets. In order to detect the large-scale instabilities of the central liquid jet, proper orthogonal decomposition (POD) was performed on the high-speed shadowgraphic images. Stereo particle image velocimetry was utilized to investigate the annular air flow fields with S in the range of 0–2.5. It was found that air swirl promotes the morphological development of the jets with S in the range of 1.2–2.5. Both the breakup length and axial distance between the first droplet separation and the nozzle exit reduce as WeA and S increase. Scaling of the first droplet locations and breakup lengths is also evaluated in this paper. In terms of the air flow fields, radial expansion of the annular swirling air jets was observed, and the annular swirling jets expand radially further as S goes up. Central reversal air flows appear near the nozzle exit when S≥1.2, and some small droplets are blown upward to the nozzle exit by these central reversal air flows. In terms of large-scale instabilities, flapping is the dominant instability across most of the flow cases (as revealed by the first POD mode). Wavy and explosive breakup appear as the secondary breakup modes when WeA is low (≤110). In the absence of the central reversal air flows, the temporal frequencies of the instabilities of the air–water interfaces increase as S goes up. It was found that the central reversal air flows tend to stabilize the air–water interfaces. The spatial frequencies of the instabilities of the air–water interfaces remain low (≤0.06 mm−1) across all the flow cases, which produce long-wave structures.
The role of Heisenberg spin exchange and the quantum Zeno effect in the spin-selective reaction between spin-1/2 and spin-1 particles
Authors: Bagryansky Victor A. , Melnikov Anatoly R. , Molin Yuri N. , Borovkov Vsevolod I.
Published: August 2022

The kinetics of spin-selective reactions involving triplet molecules, such as triplet–triplet annihilation or electron transfer to dioxygen molecules in the ground triplet spin state, are strongly dependent on the dipole–dipole interaction (DDI) of electron spins in spin-1 particles. The effect of this interaction on the intersystem crossing in the reaction encounter complex of the paramagnetic particles was previously considered for some particular cases using oversimplified approaches. In this study, we consider a rigorous kinetic model of the irreversible reaction between the spin-1/2 and spin-1 particles in an encounter complex with the reactive doublet state. This model explicitly includes both isotropic exchange coupling of the reactants and spin dependence of the reaction rate in the form of the Haberkorn reaction term. For the time-independent DDI, an analytical expression for the reaction kinetics was derived. The effect of DDI fluctuations was analyzed using numerical simulations. It was found that increasing both the exchange coupling and the reaction rate constants can significantly slow down the quartet–doublet spin transitions and, as a consequence, the observed spin-selective reaction rate. Additionally, the presence of the irreversible reaction in the doublet states affects a coherent evolution in the non-reactive quartet subsystem.
Ultrasensitive and broadband polarization-sensitive topological insulator photodetector induced by element substitution
Authors: Wang Danyang , Zhao Feiping , Zhang Fen , Mo Zhangxun , Cui Baocheng , Xia Qinglin , Li Bo , He Jun , Zhong Mianzeng
Published: August 2022

Topological insulators are considered as one of the preferred materials for high-performance optoelectronic devices due to their small bulk bandgaps and ultra-high carrier mobility. However, the existence of their unique Dirac like surface states makes the corresponding optoelectronic devices to have high dark current, and the logic circuit cannot be turned off effectively. Opening the surface state gap by element doping is an effective means to achieve high performance of devices. Here, we design and prepare single crystal Bi2Se2.15S0.85 nanowires by a facile iodine-assisted chemical vapor transport method and a fabricated individual Bi2Se2.15S0.85 nanowire based photodetector. The devices exhibit remarkable photoresponse over the broadband wavelength ranging from ultraviolet C (275 nm) to near-infrared (1310 nm) with the low dark current of 10−12 A. They show superior optoelectrical properties with an ultrafast response speed of 170 ns, detectivity of 9.35 × 1011 Jones, a competitive responsivity of 1.31 A/W, and superb stability to keep great photoresponse for at least one year, which are superior to the reported photodetectors. Additionally, benefiting from the anisotropic crystal structure of Bi2Se2.15S0.85, the devices also display good polarization detection performance in a wide spectral range from 266 nm to 1064 nm with a dichroic ratio of 1.81 at 360 nm.
Strain-driven valley states and phase transitions in Janus VSiGeN4 monolayer
Authors: Liu Pengyu , Liu Siyuan , Jia Minglei , Yin Huabing , Zhang Guangbiao , Ren Fengzhu , Wang Bing , Liu Chang
Published: August 2022

Manipulating the valley degree of freedom is an important target of valleytronics development, which provides remarkable opportunities for both fundamental research and practical applications. Here, based on first-principles calculations, we demonstrate the intrinsic valley-polarized quantum anomalous Hall effect in a monolayer ferrovalley material: Janus VSiGeN4, of which the edge states are chiral-spin-valley locking. Furthermore, a small tensile or compressive strain can drive phase transition in the material from the valley-polarized quantum anomalous Hall state to the half-valley-metal state. With the increase in the strain, the material turns into a ferrovalley semiconductor with the valley anomalous Hall effect. The origin of the phase transition is the sequent band inversion of the V d orbital at the K valleys. Moreover, we find that phase transition causes the sign reversal of the Berry curvature and induces different polarized light absorption in different valley states. Our work provides an ideal material platform for practical applications and experimental exploration of the interplay among topology, spintronics, and valleytronics.
Acoustic black hole analogy to analyze nonlinear acoustic wave dynamics in accelerating flow fields
Authors: Schenke S. , Sewerin F. , van Wachem B. , Denner F.
Published: August 2022

We present a physical model and a numerical method based on a space- and time-dependent Galilean-type coordinate transformation to simulate acoustic waves in the presence of an accelerating background flow field with sonic transition. Kinematically, the coordinate transformation is designed so as to maintain the well-posedness of the transformed wave equation, which is solved in a fixed computational domain using standard finite differences. Considering an acoustic black hole analogy, we analyze the nonlinear dynamics of acoustic waves in a stationary but non-uniformly accelerating flow field under the assumption of spherical symmetry. The choice of the acoustic black hole analogy is motivated by the fact that the steady-state spherical sonic horizon allows us to parameterize the wave-flow configuration in terms of a Helmholtz number He=c2/(λagh), which is expressed as a function of the speed of sound c, the emitted wavelength λa, and the flow acceleration at the sonic horizon, that is, the acoustic surface gravity gh. The results of the numerical simulations show that He describes geometrically similar sets of wave characteristics for different combinations of gh and λa. However, we also observe nonlinear variations of the wave amplitude along the wave characteristics, which are attributed to nonlinear Doppler modulations. It appears that these amplitude modulations depend on the acceleration of the flow field and can, therefore, differ for geometrically similar characteristics.
A chemical reaction insight of shock initiation criterion
Authors: Mu Yunfei , Zhang Wei , Shen Ruiqi , Ye Yinghua
Published: August 2022

Shock initiation criteria are essential to the shock initiation process and applications in modern pyrotechnics. The most commonly used shock initiation criteria are Walker and James criterion, which can very well describe the threshold data of the impactor with sufficient size. However, the criteria were also found not to provide a good fit to the data of thin, curve, or small flyers. By comparing the wave structure of the shock process with the stable detonation wave structure, a shock initiation criterion is developed based on the concept of the chemical reactions during the impact, focusing more on the properties of the explosives. Furthermore, a desktop micro-flyer initiating system was designed for the initiation of the thin metal flyer. The obtained data and classical historical data were analyzed with the proposed criterion, producing an excellent fit, with R2 values greater than 0.96. Compared to the existing criteria, the proposed criterion can weaken the influence of the interfacial properties of the impact and collapse the threshold velocity data with different impactor types to a single curve. The shock sensitivities of various explosives are also discussed based on the criterion. A denser impactor or the incorporation of impurities may contribute to the generation of the hot spot during the impact, leading to an increase in the sensitivity. The proposed criterion provides insight into the development of the shock initiation criteria and may help to understand the mechanism of shock initiations.
Bridging scales in a multiscale pattern-forming system
Authors: Würthner Laeschkir , Brauns Fridtjof , Pawlik Grzegorz , Halatek Jacob , Kerssemakers Jacob , Dekker Cees , Frey Erwin
Published: August 2022

Self-organized pattern formation is vital for many biological processes. Reaction–diffusion models have advanced our understanding of how biological systems develop spatial structures, starting from homogeneity. However, biological processes inherently involve multiple spatial and temporal scales and transition from one pattern to another over time, rather than progressing from homogeneity to a pattern. To deal with such multiscale systems, coarse-graining methods are needed that allow the dynamics to be reduced to the relevant degrees of freedom at large scales, but without losing information about the patterns at small scales. Here, we present a semiphenomenological approach which exploits mass conservation in pattern formation, and enables reconstruction of information about patterns from the large-scale dynamics. The basic idea is to partition the domain into distinct regions (coarse grain) and determine instantaneous dispersion relations in each region, which ultimately inform about local pattern-forming instabilities. We illustrate our approach by studying the Min system, a paradigmatic model for protein pattern formation. By performing simulations, we first show that the Min system produces multiscale patterns in a spatially heterogeneous geometry. This prediction is confirmed experimentally by in vitro reconstitution of the Min system. Using a recently developed theoretical framework for mass-conserving reaction–diffusion systems, we show that the spatiotemporal evolution of the total protein densities on large scales reliably predicts the pattern-forming dynamics. Our approach provides an alternative and versatile theoretical framework for complex systems where analytical coarse-graining methods are not applicable, and can, in principle, be applied to a wide range of systems with an underlying conservation law.
Review of post-processing methods for high-quality wire arc additive manufacturing
Authors: Bankong B. D. , Abioye T. E. , Olugbade T. O. , Zuhailawati H. , Gbadeyan O. O. , Ogedengbe T. I.
Published: August 2022

The present paper reviews the concept of wire arc additive manufacturing (WAAM), its associated defects, and the existing post-processing methods for product quality enhancement. The application of friction stir processing (a surface modification technique) for enhancing the microstructure and mechanical properties of wire arc additively manufactured parts was considered as a new horizon in this field of research. Finally, the article concludes that the widespread usage of WAAM is still challenged by some obstacles, which may need to be targeted and addressed in unique ways for different materials in order to generate functional systems in a reasonable amount of time. Unifying materials and manufacturing techniques to produce defect-free and structurally robust deposited parts will become increasingly important in the future.
Sensitivity and reproducibility of transverse magneto-optical Kerr effect (T-MOKE) ellipsometry
Authors: Martín Valderrama Carmen , Quintana Mikel , Martínez-de-Guerenu Ane , Yamauchi Tomoki , Hamada Yuki , Kurokawa Yuichiro , Yuasa Hiromi , Berger Andreas
Published: August 2022

We report a comprehensive experimental study to analyze the limiting factors and physical mechanisms that determine the achievable performance of transverse magneto-optical Kerr effect (T-MOKE) ellipsometry. Specifically, we explore different approaches to achieve high sensitivity and reduced acquisition times. The best sensitivity is observed for an incident light polarization with balanced s-p components. We also verify experimentally that the method’s theoretical description is accurately describing data for any s-p combination of the incoming light. Furthermore, two alternative measurement strategies are explored by using different measurement sequences for the polarization sensitive optics, which both achieve a very comparable, high quality of results. Signal-to-noise ratios and systematic deviations are measured and analyzed based on a large number of nominally identical measurement repeats, both for entire signal sequences as well as for individual Fourier components of the magneto-optical signal generated by a sinusoidal magnetic field sequence. Hereby, we observe that while higher order Fourier components have a significantly reduced signal amplitude and correspondingly exhibit reduced signal-to-noise and repeatability performance, signal-to-noise ratios always exceed values of 100 even for the lowest signal Fourier component and the lowest signal sample that we investigated, illustrating the extremely precise nature of T-MOKE ellipsometry.
A metamaterial based microfluidic sensor for permittivity detection of liquid
Authors: Qiu Zhikai , Xia Yu , Wang Baiyun , Hua Yujie , Li Weihan , Tang Wenxuan , Cui Tie Jun
Published: August 2022

The electromagnetic (EM) behavior of a microwave sensor has specific relationship with the physical properties of the materials to be detected, e.g. the concentration of solution and the permittivity of gas. The microwave sensor can detect changes of EM response in real time, and obtain the material properties with low sample consumption, high efficiency and dispersion characteristics. This work presents a microfluidic sensor using spiral resonators and plasmonic metamaterials with confined EM fields for intensive resonance. Two microfluidic chips with spiral channels engraved in polydimethylsiloxane are also adopted to enhance the interaction between the EM fields and the carried liquids at resonance frequencies. The permittivity of liquid samples can be detected through the shift of resonance frequency. A prototype of the sensor is fabricated and tested with several regular solutions and organic solvents, showing a good performance in terms of low liquid consumption (8 μl), good sensitivity (410 MHz frequency offset when ϵr
changes from 1 to 36.7) and low cost.
β
−p and β−α decay of the 11Be neutron halo ground state
Authors: Okołowicz J , Płoszajczak M , Nazarewicz W
Published: August 2022

Beta-delayed proton emission from the neutron halo ground state of 11Be raised much attention due to the unusually high decay rate. It was argued that this may be due to the existence of a resonance just above the proton decay threshold. In this letter, we use the lenses of real-energy continuum shell model to describe several observables including the Gamow–Teller rates for the β
−-delayed α and proton decays, and argue that, within our model, the large β
−p branching ratio cannot be reconciled with other data.
Shubnikov-de Haas and de Haas-van Alphen oscillations in Czochralski grown CoSi single crystal
Authors: Sasmal Souvik , Dwari Gourav , Baran Maity Bishal , Saini Vikas , Thamizhavel A , Mondal Rajib
Published: August 2022

Anisotropic transport, Shubnikov-de Haas (SdH), and de Haas-van Alphen (dHvA) quantum oscillations studies are reported on a high-quality CoSi single crystal grown by the Czochralski method. Temperature-dependent resistivities indicate the dominating electron-electron scattering. Magnetoresistance (MR) at 2 K reaches 610% for

I
 
∥
 
[
111
]

and

B
 
∥
 

[01

1
ˉ

], whereas it is 500% for

I
 
∥
 

[01

1
ˉ

] and

B
 
∥
 
[
111
]

. A negative slope in field-dependent Hall resistivity suggests electrons are the majority carriers. The carrier concentration extracted from Hall conductivity indicates no electron–hole compensation. In 3D CoSi, the electron transport lifetime is found to be approximately in the same order as the quantum lifetime, whereas in 2D electron gas the long-range scattering drives the transport life much larger than the quantum lifetime. From MR and Hall SdH oscillations, the effective masses and Dingle temperatures have been calculated. The dHvA oscillation reveals three frequencies at 18 T (γ), 558 T (α) and 663 T (β), whereas, SdH oscillation results in only two frequencies α and β. The γ frequency observed in dHvA oscillation is a tiny hole pocket at the Γ point.
Synthesis and structural link to the electronic and magneto-transport properties of spin–orbit Mott insulator Sr2IrO4
Authors: Sharma Priyamedha , Singh Saurabh , Kuga Kentaro , Takeuchi Tsunehiro , Bindu R
Published: August 2022

We investigate the effect of sample preparation conditions on the link between the structural and physical properties of polycrystalline spin—orbit Mott insulator, Sr2IrO4. The samples were prepared in two batches. With the first batch prepared as per the commonly adopted procedure in literature and the second batch prepared adopting the same procedure as the first batch but with an additional annealing in vacuum. Interestingly, our results show that without change in the value of the Curie temperature (T
C
), there occurs increase in the value of magnetization, resistivity, magneto-resistance (MR) and an increase in temperature range of stabilization of the canted antiferromagnetic structure. The temperature behaviour of the difference in the irreversible magnetization between the samples is in line with the difference in the Ir–O–Ir in-plane bond angle. At low temperatures, the conduction mechanism in the first batch of the sample is mainly governed by disorder while in the case of the other sample it is of Arrhenius type. The magneto-transport results have shown its strong link with the disorder and structural results. Although the nature and mechanism of the disorder needs to be investigated further, the present results throw light on the role of disorder and its connectivity between the structure and physical properties to understand its complex behaviours.
Accurate segmentation of breast tumor in ultrasound images through joint training and refined segmentation
Authors: Shen Xiaoyan , Wu Xinran , Liu Ruibo , Li Hong , Yin Jiandong , Wang Liangyu , Ma He
Published: August 2022

Objective. This paper proposes an automatic breast tumor segmentation method for two-dimensional (2D) ultrasound images, which is significantly more accurate, robust, and adaptable than common deep learning models on small datasets. Approach. A generalized joint training and refined segmentation framework (JR) was established, involving a joint training module (J

module
) and a refined segmentation module (R

module
). In J

module
, two segmentation networks are trained simultaneously, under the guidance of the proposed Jocor for Segmentation (JFS) algorithm. In R

module
, the output of J

module
is refined by the proposed area first (AF) algorithm, and marked watershed (MW) algorithm. The AF mainly reduces false positives, which arise easily from the inherent features of breast ultrasound images, in the light of the area, distance, average radical derivative (ARD) and radical gradient index (RGI) of candidate contours. Meanwhile, the MW avoids over-segmentation, and refines segmentation results. To verify its performance, the JR framework was evaluated on three breast ultrasound image datasets. Image dataset A contains 1036 images from local hospitals. Image datasets B and C are two public datasets, containing 562 images and 163 images, respectively. The evaluation was followed by related ablation experiments. Main results. The JR outperformed the other state-of-the-art (SOTA) methods on the three image datasets, especially on image dataset B. Compared with the SOTA methods, the JR improved true positive ratio (TPR) and Jaccard index (JI) by 1.5% and 3.2%, respectively, and reduces (false positive ratio) FPR by 3.7% on image dataset B. The results of the ablation experiments show that each component of the JR matters, and contributes to the segmentation accuracy, particularly in the reduction of false positives. Significance. This study successfully combines traditional segmentation methods with deep learning models. The proposed method can segment small-scale breast ultrasound image datasets efficiently and effectively, with excellent generalization performance.
Nanoscale active tuning of the second harmonic generation efficiency in semiconductors from super-low to gigantic values
Authors: Aşırım Özüm Emre , Kuzuoglu Mustafa
Published: August 2022

Second harmonic generation efficiency (SHGE) strongly depends on the length of the interaction material along the beam propagation axis. Since a nanoscale interaction length is considered too short even in the optical wavelength scale, the attained SHGE through nanomaterials is usually too low to be of practical use. In this study, it will be shown that by properly adjusting the conduction-band electron density in a semiconductor nanomaterial under a certain optical pumping rate (active tuning), the SHGE can be effectively tuned from being super-low to being ultra-high. Such sharp tunability is only valid for small-scale materials as their density of conduction-band electrons can be rapidly switched between high and low under moderate optical pumping. Using an experimentally verified computational model, we have observed that at a given frequency, for a certain range of conduction-band electron densities, the SHGE can reach up to 1080% for Ga-As and 230% for silicon nanomaterials under active tuning, with respect to the intensity of the first harmonic of the input signal. Such SHGEs are unprecedented, which is very promising for generating higher harmonics via cascaded second harmonic generation performed via adaptive tuning of the conduction band electron density at each stage.