bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental investigation on the hysteresis in low-pressure inductively coupled neon discharge
Authors: Hong Young-Hun , Kim Tae-Woo , Kim Ju-Ho , Lim Yeong-Min , Lee Moo-Young , Chung Chin-Wook
Published: September 2022

A hysteresis phenomenon observed in neon inductive discharge at low gas pressure is investigated in terms of the evolution of the electron energy distribution function (EEDF). Generally, the hysteresis phenomenon has been reported at high-pressure Ramsauer gas discharges. However, in neon plasma, we found that the hysteresis phenomenon occurs even at low gas pressure (5 mTorr). Furthermore, the hysteresis vanishes with an increase in the gas pressure (10 and 25 mTorr). To analyze this hysteresis, the EEDF is measured depending on the radio frequency power. The EEDF at 10 mTorr sustains the bi-Maxwellian distribution during an E–H transition. On the other hand, the EEDF at 5 mTorr changes dramatically between discharge modes. At 5 mTorr, the measured EEDF for the E mode has the Maxwellian distribution due to high collisional heating in the bulk plasma. The EEDF for the H mode has the bi-Maxwellian distribution because collisionless heating in the skin depth is dominant. This apparent evolution of the EEDF causes a nonlinear energy loss due to collisions during the discharge mode transition. Therefore, the plasma can maintain the H mode discharge with high ionization efficiency, even at a lower applied power, which results in the hysteresis.
Deep learning-assisted multifunctional wavefront modulation with Willis coupling
Authors: Gao Hao , Wang Ze-Wei , Xu Zi-Xiang , Yang Jing , Liang Bin , Cheng Jian-Chun
Published: September 2022

Diverse wavefront modulations with multifunctional acoustic devices have been of great interest to physics and engineering communities. However, traditional design methods of multifunctional acoustic devices rely on a deterministic physical model and redundant iterative optimization, resulting in inflexibility and consuming of time. In this work, we present and experimentally implement a deep learning-assisted tunable acoustic metagrating for multifunctional wavefront modulation with 95.2% accuracy and a 105 order of magnitude decrease in computational time compared to a classical optimization method. The presented tunable structure formed by a periodic array of 3C-shaped unit cells excites controllable Willis coupling, exhibiting corresponding asymmetrical scattering patterns. With the support of a deep learning strategy, the optimal configuration between structure parameters and Willis coupling magnitude could be efficiently confirmed, realizing various extraordinary wavefront modulations, including abnormal reflection, perfect beam splitting, and multi-channel energy distribution in arbitrary ratios. The polarizability tensor retrieval method is used to characterize the Willis coupling of different modulation structures, demonstrating the refined abstraction of the deep learning strategy on Willis coupling. Meanwhile, the numerical and experimental results are in good agreement with the desired wavefront modulation, verifying the effectiveness of the proposed method. Our work develops deep learning-assisted multifunctional wavefront modulation with the advantages of high accuracy, efficiency, flexibility, and refined abstraction of a physical mechanism, paving the way for a combination of deep learning and pragmatic multifunctional acoustic applications.
Indirect energy transfer channel between fast ions via nuclear elastic scattering observed on the large helical device
Authors: Matsuura H. , Kimura K. , Umezaki D. , Ogawa K. , Isobe M. , Kawamoto Y. , Oishi T. , Goto M. , Tamura N. , Osakabe M. , Nishitani T. , Sugiyama S.
Published: September 2022

An energy transfer phenomenon between energetic ions, which cannot be explained only considering the Coulomb scattering process, was observed on a large helical device (LHD). This phenomenon often occurs in fusion reactivity enhancement and fast-ion slowing-down process that can be observed as a delay in the decay time of the D(d,n)3He neutron generation rate. The transferred energy required to induce such a reactivity enhancement or delay in the fast-ion slowing-down time (neutron decay time) was examined based on the Boltzmann−Fokker−Planck analysis in which a discrete energy transfer process, called nuclear elastic scattering (NES), is included. It was shown that even though the cross section of the NES is smaller than that of the Coulomb scattering, enough knock-on population appears in the energetic region in ion distribution function to induce the observable NES effects; thus, enough energy is transferred from beam ions to fast component of bulk ion distribution function indirectly and the transferred energy per unit time via NES is comparable to the Coulomb scattering rate. This study analytically demonstrates that the observed phenomena on LHD can be explained smoothly by considering the alternative indirect energy transfer channel between energetic ions, which can be comparable with the one via Coulomb scattering.
Manipulation of magnetic anisotropy by voltage induced strain in Co2MnAl/PMN-PT heterostructure
Authors: Ozdemir O. , Altındal A. , Colakerol Arslan L.
Published: September 2022

We have investigated the effect of an external electric field on the magnetic properties of Co2MnAl thin films deposited on a lead magnesium niobate-lead titanate (PMN-PT) (011) substrate. Stain-induced magnetoelectric coupling affects the magnetic properties of the Co2MnAl/PMN-PT system. The piezo-strain induced by applying an external field normal to the surface induces only in-plane strain, which leads to the rotation of easy-axis orientation of Co2MnAl from [100] to [011¯] direction. The remanent magnetization states and coercivity of the Co2MnAl film vary significantly and asymmetrically with the applied voltage due to anisotropic strain originating from PMN-PT. Electrical control of magnetic anisotropy in a Co2MnAl Heusler compound at room temperature will be of interest for realizing next-generation magnetoelectric random access memory devices.
Research on the spatio-temporal characteristics of high energy pulsed plasma jets
Authors: Zhang Pengfei , Liu Xin , Lin Mengjiao , Zhang Jia
Published: September 2022

This research proposes a high-energy pulsed plasma jet for producing highly dynamic and huge gradient plasma. The injected plasma enters the plasma sheath, and the stealth of the high-speed vehicle is achieved by modulating the dynamics of the plasma sheath electron density. The characteristics of the plasma were extensively diagnosed using current–voltage measurements, high-speed cameras, and optical emission spectroscopy. This includes the electrical parameters of the plasma and its spatial and temporal distribution. The deposited energy rises and then falls as the pressure rises. The high-speed camera determines that the plasma injection process lasted 160.04 μs. The electron temperature ranges from 0.68 to 1 eV. The electron density ranges from 2.5 × 1016 to 2.1 × 1017 cm−3 with an increasing trend from 0 to 12 μs and a decreasing trend from 12 to 28 μs. As the axial position rises, the electron density gradually decays. The analysis of high-energy pulsed plasma jets provides the framework for future research into active stealth in high-speed vehicles.
Variational algorithm of quantum neural network based on quantum particle swarm
Authors: Dong Yumin , Xie Jianshe , Hu Wanbin , Liu Cheng , Luo Yi
Published: September 2022

Most models of quantum neural networks are optimized based on gradient descent, and like classical neural networks, gradient descent suffers from the barren plateau phenomenon, which reduces the effectiveness of optimization. Therefore, this paper establishes a new QNN model, the optimization process adopts efficient quantum particle swarm optimization, and tentatively adds a quantum activation circuit to our QNN model. Our model will inherit the superposition property of quantum and the random search property of quantum particle swarm. Simulation experiments on some classification data show that the model proposed in this paper has higher classification performance than the gradient descent-based QNN.
Electron scattering with ethane adsorbed on rare gas multilayers: Hole transfer, coulomb decay, and ion dissociation
Authors: Kundu Sramana , Hu Hang , Li Xiaosong , Schaible Micah , Orlando Thomas M.
Published: September 2022

Positive ion desorption following electron impact dissociative ionization of ethane adsorbed on Ar, Kr, and Xe multilayers has been studied as a function of incident electron energy from threshold to 100 eV. Based on the dependence of ion yields on the identity of the rare gas, it is likely that the majority of ethane molecules undergo indirect ionization following hole transfer from the ionized underlying rare gas. This has also been corroborated by density of states calculations showing the energetic alignment of the outer valence states of ethane and the condensed rare gas ionization energies. Due to the near-resonant nature of charge transfer for single-hole states, the ethane molecular ion is excited to different final ionic states on different rare gases, which leads to differences in ion desorption yields and branching ratios. The quantitative yields increase with increasing ionization energy gap between the rare gas and ethane, in the order Ar > Kr > Xe. The large increase in yields from 25 eV onwards for all rare gases is likely due to the formation and decay of two-hole states on neighboring rare gas and ethane molecules due to interatomic and intermolecular Coulomb decay (ICD) and not electron transfer mediated decay (ETMD). The ICD and ETMD pathways become accessible when the incoming electron has sufficient energy to excite the inner valence ns level of the rare gas to a Rydberg state or ionize it. The experimental findings are supported by calculations of thresholds, density of states for the final configurations of these processes, and coupling strengths for hole transfer between ethane and rare gases. The fragment ion branching ratios vary with energy from threshold to about 35 eV, showing the fragmentation pattern changes with the mode of hole transfer and availability of excess energy. Sigma C–C bonds are more likely to break than C–H bonds in the mid-20 eV range, and this effect is most pronounced for Xe, followed by Kr, and then Ar.
Transient characteristics of a typical vacuum ejector—An experimental study
Authors: Raju Martin , Desikan S. L. N. , Vaidyanathan Aravind
Published: September 2022

Using simultaneous measurements of unsteady pressures in conjunction with time-resolved Schlieren images and oil flow visualization, we investigate the characteristics of a typical vacuum ejector's starting transient, steady-state, and shut-down transient. With varying primary jet chamber pressure, the pressure evolution in the secondary chamber shows smooth, perturbed, rapid, and steady evacuation stages, as well as hysteresis and rapid filling stages. It is noticed that the evacuation in the secondary chamber is improved during stopping transient just before the unstart event. By using oil flow images, we illustrate the separation bubble characteristics during each stage of the vacuum ejector operation and their influence on the pressure evolution. Through cross correlation, it has been determined that the primary jet flapping during the starting transient causes the jet to attach to one of the diffuser walls. We also demonstrate that the primary jet undergoes both longitudinal and lateral oscillations in the starting transient, the former having a major effect on unsteadiness in the secondary chamber using proper orthogonal decomposition and spectral proper orthogonal decomposition algorithms and power spectral density (PSD). Simultaneous acquisition of unsteady pressures and high-speed Schlieren images allow us to correlate the frequency peaks (PSD spectra) in the flow. Using magnitude-squared coherence and cross correlation analyses, we confirm communication of unsteadiness and its direction of propagation between the secondary chamber and the diffuser. In this study, we demonstrate that a high ramping rate of primary jet chamber pressure reduces the unsteadiness in the secondary chamber during the transient starting phase.
Computing contact angles for oil–water–rock systems via thermodynamic integration
Authors: Patel Rohan , Addula Ravi Kumar Reddy , Shaik Majeed , Punnathanam Sudeep N.
Published: September 2022

Wettability of rock surfaces with respect to oil and water, which is characterized by the contact angle, is an important factor that determines the efficacy of enhanced oil recovery operations. Experimental determination of contact angles for oil–water–rock systems is expensive and time-consuming due to the extremely long times needed for the establishment of adsorption equilibrium at the liquid–solid interface. Hence, molecular simulations form an attractive tool for computing contact angles. In this work, we use the cleaving wall technique that was developed previously in our group [R. K. R. Addula and S. N. Punnathanam, J. Chem. Phys. 153, 154504 (2020)] to compute solid–liquid interfacial free energy, which is then combined with Young’s equation to compute the oil–water contact angle on silica surfaces. The silica surface is modeled with the INTERFACE force field that has been developed to accurately reproduce experimental data. We have considered three different surface chemistries of silica, namely, Q2, Q3, and Q4, in this study. Our calculations reveal that while the Q2 and Q3 surfaces are completely wetted by water, the Q4 surface is partially non-wetted by water. All the simulations needed for this calculation can be performed using the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) molecular package. This should facilitate wider adoption of the Young’s equation route to compute contact angles for systems comprised of complex molecules.
Ultrasonication assisted exfoliation of MoSe2 nanosheets for optical and optical power limiting applications
Authors: Ramar Venkadeshkumar , Pataniya Pratik M. , Gunvant Solanki , Karthikeyan B.
Published: September 2022

We report direct, economic, and facile preparation of two-dimensional transition metal dichalcogenide material molybdenum diselenide nanosheets through the ultrasonication assisted liquid exfoliation method. The optical absorption spectra confirm the formation of MoSe2 nanosheets. The Kramers–Kronig expression was used to estimate the refractive index and extinction coefficient values of the prepared nanosheets. The emission properties of the prepared samples were done using photoluminescence spectroscopy. The nonlinear optical studies were performed using an open aperture Z-scan method under nanosecond pulsed laser excitation of a second harmonic generation wavelength of 532 nm. The obtained results demonstrate the strong optical power limiting (OPL) properties of the MoSe2 nanosheets. This OPL is due to two-photon absorption behavior of MoSe2 nanosheets.
Pressure-directed mixed ionic–electronic to pure electronic conduction transition and enhanced grain boundary conductivity in solid electrolyte CdMoO4
Authors: Qin Tianru , Duan Susu , Yue Donghui , Li Jianfu , Wang Qinglin , Wang Fangxu , Chen Weiwei , Wang Xiaoli , Zheng Youjin , Gao Chunxiao
Published: September 2022

Scheelite ABO4-type solid electrolytes have attracted much attention for potential applications as oxygen ionic conductors of solid oxide fuel cells. Herein, a systematic study was carried out on the electrical transport properties of CdMoO4 under high pressure by impedance spectroscopy measurements and theoretical calculations. The sequence of structural phase transitions at pressures was determined as I41/a → C2/c → P21/c by the Crystal structure AnaLYsis by Particle Swarm Optimization (CALYPSO) method. A pressure-induced conduction transition from mixed ionic–electronic to pure electronic conduction was observed. Below 25.6 GPa, O2− ions play a major role in the electrical transport process. The microscopic transport mechanism was analyzed with grain boundary energies and migration energy barriers. Above 26.9 GPa, the grain boundary response was weakened significantly after a pressure cycle, and the grain boundary conductivity increased by about three times due to pressure. These results provide guidelines for the optimization and application of scheelite ABO4-based oxygen ionic conductors in solid oxide fuel cells.
β
-Ga2O3 MESFETs with insulating Mg-doped buffer grown by plasma-assisted molecular beam epitaxy
Authors: Dheenan Ashok V. , McGlone Joe F. , Kalarickal Nidhin Kurian , Huang Hsien-Lien , Brenner Mark , Hwang Jinwoo , Ringel Steven A. , Rajan Siddharth
Published: September 2022

In this work, we develop in situ Mg doping techniques in plasma-assisted molecular beam epitaxy (PAMBE) of β-Ga2O3 to compensate Si dopants at the substrate epilayer growth interface and eliminate parasitic leakage paths. Both abrupt and uniform Mg doping profiles over a wide range of concentrations were achieved in β-Ga2O3 epilayers grown by PAMBE. Capacitance–voltage characteristics of Si and Mg co-doped samples confirmed the compensating effect of the Mg dopants. Mg delta-doping was then integrated into a β-Ga2O3 metal-semiconductor field effect transistor structure and shown to be effective in eliminating source leakage. The results presented here show that Mg doping is a promising way to engineer insulating buffer layers for β-Ga2O3 lateral devices grown by PAMBE.
A new current injection and voltage measurement strategy of 3D electrical impedance tomography based on scanning electrode
Authors: Liu Jinzhen , Zhu Zhaoqi , Xiong Hui , Li Chunchan , Chen Yunjun
Published: September 2022

Electrical impedance tomography (EIT) technology is an important imaging approach to show the conductivity distribution of the area noninvasively. Recently, 3D EIT has been extensively studied for its more comprehensive display of electrical properties. Nonetheless, most 3D EIT electrode models are based on multilayer ring electrodes and only suitable for specific scenarios. In order to overcome its limitations and alleviate the ill-condition of 3D EIT, we propose a new current injection and voltage measurement strategy based on scanning row electrodes (SRE) called the back electrode excitation (BEEM) strategy and select the optimal number of excitation electrodes according to different imaging effects. A 3D electrical impedance imaging system based on SRE is designed. Then, the traditional excitation measurement strategy is introduced, and the two strategies are compared through simulation and actual experiments. The results show that the BEEM strategy with SRE can not only obtain rich potential information in the finite field but also significantly improve the imaging detection depth, accuracy, and noise immunity compared with the flat electrode array.
Numerical investigation of multiscale lateral microstructures enhancing passive micromixing efficiency via secondary vortex flow
Authors: Niu Dong , Chen Jinlan , Xiong Ming , Cao Yunyi , He Chunmeng , Chen Jinju , Liu Hongzhong
Published: September 2022

Passive micromixing can efficiently mix laminar flows through molecular and convective diffusion. Microstructures are expected to be efficient, easily integrated into micromixers, and suitable for micromixers over a wide range of Re. This paper presents the enhancement effects of the multiscale lateral microstructures on the flow field characteristics and mixing efficiency through numerical simulations at Re = 0.01–50. Inspired by the regulation of lateral microstructures on the local flow field, cross-scale staggered baffles (CSBs) were established and applied in typical passive micromixers. For low-Re conditions, the paired trapezoidal microstructures (PTMs) of the CSBs improved the mixing effect by increasing the local streamline tortuosity. For high-Re conditions, the PTMs of CSBs increased the number of expanding vortices in the microchannel, which could increase the size of the fluid interfaces, and an optimal mixing index with relatively little pressure drop was achieved. Moreover, the CSBs were applied to the serpentine curved channel, which caused large expanding vortices on the inner side of the curved channel, and then the state of the Dean vortices on the cross section of the curved channel changed. Therefore, compared with the conventional micromixer channel structure, lateral microstructures regulate the local flow field through the enhancement of the streamlines and the secondary flow effects, and lateral microstructures have great potential to improve the mixing efficiency over a wide range of Re.
Scanning probe microscope probe switching unit with electrical measurement for in situ multifunctional characterization: Design and preliminary application in tribocorrosion investigation
Authors: Chen Yushan , Xu Wenbin , Jiang Liang , Qian Linmao
Published: September 2022

Scanning probe microscope (SPM) is a potent tool in nanotribology research. However, commercial environment control SPMs can install only one probe to perform one function at a time. Accordingly, this study developed a probe switching unit with electrical measurement for in situ multifunctional characterization. The unit mainly comprises a cover, a rotation stage, and a probe holder assembly. Four probes can be installed. One is electrically connected to perform tapping mode and electrical measurement such as Kelvin probe force microscope (0.01 mV resolution), while the other three are to perform contact mode. The rotation stage drives the assembly to switch probes to in situ measure multiple physical quantities in a controlled environment. The unit was preliminarily applied to investigate tantalum tribocorrosion. Based on the changing trends of wear amount and surface potential change, the wear process can be roughly divided into three stages, which may be caused by desorption of the adsorbed air, wear of the oxide film, and wear of the substrate, respectively. Moreover, wear can lead to a surface potential increment, which may partly contribute to the galvanic corrosion between the virgin area and the wear area. The unit may serve as a useful tool for nanotribology research.
Prediction of flows in enclosed rotor–stator cavities
Authors: Bailey Nicola Y. , Owen J. Michael , Mear Isaac F. , Tang Hui
Published: September 2022

A robust and fully predictive mathematical representation has been derived to predict the swirl ratio, pressure, and torque in enclosed rotor–stator cavities. For the flow regime of interest, turbulent boundary layers form on the rotor and stator, between which there is an inviscid fluid core. Utilizing the momentum-integral equations with suitable assumptions and the continuity of mass equation, governing equations are derived for the flow behavior, with the assumption that the swirl ratio is dependent on the radius. Predictive initial conditions are formulated, and a robust, computationally inexpensive numerical technique is implemented and predictions are shown to be in reasonable agreement with existing experimental data. The swirl ratio was proven to be highly dependent on the radius, with the distribution modified by the shroud and hub conditions. Additionally, the effects of two geometrical parameters were studied, namely, the gap ratio and non-dimensional inner radius. As the gap ratio increases from 0.05 to 0.5, the swirl ratio at the outer radius decreases from 0.56 to 0.35, leading to an increase in torque coefficient from 0.38 to 0.44. The swirl ratios for different inner radii differ at the inner part of the cavity while converging to a single value at the outer radius. The presented model can easily be integrated into the design code for gas turbine engines, contributing to the design of more efficient engines.
Prediction uncertainty validation for computational chemists
Authors: Pernot Pascal
Published: September 2022

Validation of prediction uncertainty (PU) is becoming an essential task for modern computational chemistry. Designed to quantify the reliability of predictions in meteorology, the calibration-sharpness (CS) framework is now widely used to optimize and validate uncertainty-aware machine learning (ML) methods. However, its application is not limited to ML and it can serve as a principled framework for any PU validation. The present article is intended as a step-by-step introduction to the concepts and techniques of PU validation in the CS framework, adapted to the specifics of computational chemistry. The presented methods range from elementary graphical checks to more sophisticated ones based on local calibration statistics. The concept of tightness, is introduced. The methods are illustrated on synthetic datasets and applied to uncertainty quantification data issued from the computational chemistry literature.
Vibrational energy levels and predissociation lifetimes of the A2Σ+ state of SH/SD radicals by photodissociation spectroscopy
Authors: Qin Yuan , Zheng Xianfeng , Song Yu , Sun Ge , Zhang Jingsong
Published: September 2022

Photo-predissociation of SH and SD radicals in the A2Σ+ state is investigated using the high-n Rydberg atom time-of-flight technique. By measuring the photoproduct translational energy distributions as a function of excitation wavelength, contributions from overlapping A2Σ+ (v′) ← X2Π (v″) transitions can be separated, and the H/D + S(3PJ) photofragment yield (PFY) spectra are obtained across various rovibrational levels (SH v′ = 0–7 and SD v′ = 0–8) of the A2Σ+ ← X2Π bands. The upper A2Σ+ state vibrational levels v′ = 5–7 of SH and v′ = 3–8 of SD are determined for the first time. The PFY spectra are analyzed with the simulation program PGOPHER [C. M. Western, J. Quant. Spectrosc. Radiat. Transfer 186, 221 (2016)], which gives vibrational origins and linewidths of the rovibrational levels of the A2Σ+ state. The linewidths (≥1.5 cm−1) of the SH A2Σ+ v′ = 3–7 and SD A2Σ+ v′ = 2–8 states are characterized for the first time in this work, demonstrating that these levels undergo rapid predissociation with lifetimes on the order of picosecond. The lifetimes of the SD A2Σ+ v′ = 0, N′ = 1 and 2 levels are determined to be 247 ± 50 ns and 176 ± 60 ns by pump–probe delay measurements, respectively. The experimentally measured lifetimes are in reasonable agreement with the theoretical predictions.
Confinement of volatile fission products in the crystalline organic electride Cs+(15C5)2•e−
Authors: Kuganathan Navaratnarajah , Chroneos Alexander , Grimes Robin W.
Published: September 2022

The efficacy of filters to trap volatile radiotoxic nuclear fission products depends on the thermodynamic stability of these species within the filter material. Using atomic scale modeling based on density functional theory together with a dispersion correction, we predict the structures and energies of volatile fission product atoms and molecules trapped by a crystalline organic electride Cs+(15C5)2•e−. Endothermic encapsulation energies indicate that Kr and Xe are not captured by this electride. Conversely, encapsulation is very strong for Br, I, and Te, with respect to atoms and dimers as reference states, leading to the formation of trapped Br−, I−, and Te− ions. While both Rb and Cs are encapsulated exothermically (without significant charge transfer), their encapsulation is markedly weaker than that calculated for Br, I, and Te. Encapsulation of homonuclear dimers (Br2, I2, and Te2) as anionic molecular species is thermodynamically favorable, though they will disproportionate if sufficient encapsulation sites are available. Conversely, encapsulation of heteronuclear dimers (Rb–Br, Rb–I, Cs–Br, and Cs–I) is unfavorable with respect to their bulk solids as reference states.
UV photodissociation action spectra of protonated formylpyridines
Authors: McKinnon Benjamin I. , Marlton Samuel J. P. , Dezalay Jordan , Soorkia Satchin , Blanksby Stephen J. , Trevitt Adam J.
Published: September 2022

The first ππ* transition for protonated 2-, 3-, and 4-formylpyridine (FPH+) (m/z 108) is investigated by mass spectrometry coupled with photodissociation action spectroscopy at room temperature and 10 K. The photoproduct ions are detected over 35 000–43 000 cm−1, and the major product channel for 3-FPH+ and 4-FPH+ is the loss of CO forming protonated pyridine at m/z 80. For 2-FPH+, the CO loss product is present but a more abundant photoproduct arises from the loss of CH2O to form m/z 78. Plausible potential energy pathways that lead to dissociation are mapped out and comparisons are made to products arising from collision-induced dissociation. Although, in all cases, the elimination of CO is the overwhelming thermodynamically preferred pathway, the protonated 2-FPH+ results suggest that the CH2O product is kinetically driven and competitive with CO loss. In addition, for each isomer, radical photoproduct ions are detected at lower abundances. SCS-CC2/aug-cc-pVTZ Franck–Condon simulations assist with the assignment of vibrionic structure and adiabatic energies (0–0) for 2-FPH+ at 36 560 cm−1, 37 430 cm−1 for 3-FPH+, and 36 140 cm−1 for 4-FPH+, yielding an accurate prediction, on average, within 620 cm−1.
(NH4)2S-induced improvement of interfacial wettability for high-quality heterojunctions to boost the chloride-assembled CZTSSe solar cells
Authors: Yu Lei , Dong Xiaofei , Yang Fengxia , Sun Xudong , Chen Jiangtao , Zhang Xuqiang , Zhao Yun , Li Yan
Published: September 2022

Concernin the crucial interfacial issues in multi-layered kesterite Cu2ZnSn(S,Se)4 (CZTSSe) solar cells, (NH4)2S treatment has been proven to be effective in eliminating surface secondary phases. While for the CZTSSe absorbers without impurity phases, what can the low-temperature (NH4)2S treatment do to the absorbers, thus to the device performance? Herein, the chloride-fabricated CZTSSe absorbers are surface treated with the (NH4)2S solution at room temperature, and its influence on the device performance is investigated in detail. Surprisingly, such treatment can make the absorbers’ surface become nearly super-hydrophilicity, greatly decreasing the surface wetting angle from 63.1° ± 3.4° to 7.3° ± 0.6° after 50 min-treating, and thus lead to marked differences in the interfacial properties of the CdS/CZTSSe heterojunctions deposited in a chemical bath. Consequently, for the best-performing CZTSSe cells, combining the passivated interfacial defects, increased carrier concentration, reduced carrier recombination, and prolonged minority lifetime, the efficiency is improved from 6.54% to 9.88%, together with the 37 mV and 7.9% increase in VOC and FF, respectively. This study confirms the newfound results that the (NH4)2S treatment can effectively adjust the wettability of the absorbers to form high-quality heterojunctions to boost the device efficiency, which would be valuable for an in-depth understanding of the intrinsic mechanisms of interfacial processing.
Chaotic rotation of a finite-size spheroidal particle in oscillating shear flows with fluid inertia
Authors: Jiang Xinyu , Huang Weixi , Xu Chunxiao , Zhao Lihao
Published: September 2022

Rotational dynamics of a prolate spheroid in oscillating shear flows is studied by fully resolved direct numerical simulations with an immersed boundary method. In this flow configuration, we extend the work of Nilsen and Andersson [“Chaotic rotation of inertial spheroids in oscillating shear flow,” Phys. Fluids 25, 013303 (2013)] with focusing on the fluid inertia effect. We observe that the spheroid could rotate in chaotic and nonchaotic modes, which are identified by the sign of a largest Lyapunov exponent of the dynamic system. These two distinct rotation modes depend on both particle Reynolds number and oscillation frequency. For a certain Reynolds number, chaotic rotation appears when oscillation frequency is lower than a critical value, which decreases linearly with the increase of the particle Reynolds number. Based on this finding, we propose an empirical expression to predict the rotation mode. We, furthermore, discuss the mechanism of the emergence of the chaotic rotation, which is ascribed to a nonlinear interaction between time-varying orientation of the inertial spheroid and the oscillation of the shear rate.
Dielectric and thermal performance of a C60-based nanofluid and a C60-loaded ferrofluid
Authors: Rajňák Michal , Kurimský Juraj , Paulovičová Katarína , Franko Marek , Dolník Bystrík , Cimbala Roman , Timko Milan , Kopčanský Peter , Girman Vladimír , Lisnichuk Maksym
Published: September 2022

Liquids in electrical devices often act as electrical insulators and cooling media. To enhance both dielectric and thermal properties of liquids, various nanoparticles can be dispersed in the liquids resulting in effective nanofluids. In this research, a new generation transformer oil prepared by a gas-to-liquid technology has been used to prepare a mono-nanofluid with fullerene C60 nanoparticles (0.01%w/V) and a hybrid nanofluid with C60 (0.01%w/V) and iron oxide nanoparticles (0.01%w/V), so-called C60-loaded ferrofluid. Both nanofluids and the oil were subjected to experimental investigation of frequency-dependent dielectric response, dielectric breakdown, and thermal conductivity at various temperatures. Finally, the three liquids were applied in a single-phase transformer, and temperature rise tests of the loaded transformer were conducted. The dielectric spectroscopy revealed three orders of magnitude higher dielectric losses in C60-loaded ferrofluid than in the oil and C60 nanofluid, where the losses are of conducting nature. In C60-loaded ferrofluid, an interfacial relaxation process is considered in addition. C60 particles in the oil increased its breakdown voltage by 17%, while the mixture of C60 and magnetic nanoparticles resulted in a 12.5% reduction of the breakdown voltage. The enhancement has been ascribed to the strong capacity of C60 to absorb electrons and their ability to weaken the photoionization in the head of the streamer. The thermal conductivity of both nanofluids decreases with temperature, and the effective medium theory can well predict it. A significant decrease in the transformer temperature rise up to 8 K has been found for C60 nanofluid, as compared with the temperature rise achieved with the transformer oil. The temperature rise was also reduced with C60-loaded ferrofluid (up to 5.6 K). The lower cooling efficiency of the hybrid nanofluid was attributed to the high dielectric losses generating undesirable heat with a counter-productive effect on the cooling process.
Arsenite toxicity is regulated by queuine availability and oxidation-induced reprogramming of the human tRNA epitranscriptome
Authors: Huber Sabrina M. , Begley Ulrike , Sarkar Anwesha , Gasperi William , Davis Evan T. , Surampudi Vasudha , Lee May , Melendez J. Andres , Dedon Peter C. , Begley Thomas J.
Published: September 2022

Cells respond to environmental stress by regulating gene expression at the level of both transcription and translation. The ∼50 modified ribonucleotides of the human epitranscriptome contribute to the latter, with mounting evidence that dynamic regulation of transfer RNA (tRNA) wobble modifications leads to selective translation of stress response proteins from codon-biased genes. Here we show that the response of human hepatocellular carcinoma cells to arsenite exposure is regulated by the availability of queuine, a micronutrient and essential precursor to the wobble modification queuosine (Q) on tRNAs reading GUN codons. Among oxidizing and alkylating agents at equitoxic concentrations, arsenite exposure caused an oxidant-specific increase in Q that correlated with up-regulation of proteins from codon-biased genes involved in energy metabolism. Limiting queuine increased arsenite-induced cell death, altered translation, increased reactive oxygen species levels, and caused mitochondrial dysfunction. In addition to demonstrating an epitranscriptomic facet of arsenite toxicity and response, our results highlight the links between environmental exposures, stress tolerance, RNA modifications, and micronutrients.
Green diatom mutants reveal an intricate biosynthetic pathway of fucoxanthin
Authors: Bai Yu , Cao Tianjun , Dautermann Oliver , Buschbeck Paul , Cantrell Michael B. , Chen Yinjuan , Lein Christopher D. , Shi Xiaohuo , Ware Maxwell A. , Yang Fenghua , Zhang Huan , Zhang Lihan , Peers Graham , Li Xiaobo , Lohr Martin
Published: September 2022

Fucoxanthin is a major light-harvesting pigment in ecologically important algae such as diatoms, haptophytes, and brown algae (Phaeophyceae). Therefore, it is a major driver of global primary productivity. Species of these algal groups are brown colored because the high amounts of fucoxanthin bound to the proteins of their photosynthetic machineries enable efficient absorption of green light. While the structure of these fucoxanthin-chlorophyll proteins has recently been resolved, the biosynthetic pathway of fucoxanthin is still unknown. Here, we identified two enzymes central to this pathway by generating corresponding knockout mutants of the diatom
Phaeodactylum tricornutum
that are green due to the lack of fucoxanthin. Complementation of the mutants with the native genes or orthologs from haptophytes restored fucoxanthin biosynthesis. We propose a complete biosynthetic path to fucoxanthin in diatoms and haptophytes based on the carotenoid intermediates identified in the mutants and in vitro biochemical assays. It is substantially more complex than anticipated and reveals diadinoxanthin metabolism as the central regulatory hub connecting the photoprotective xanthophyll cycle and the formation of fucoxanthin. Moreover, our data show that the pathway evolved by repeated duplication and neofunctionalization of genes for the xanthophyll cycle enzymes violaxanthin de-epoxidase and zeaxanthin epoxidase. Brown algae lack diadinoxanthin and the genes described here and instead use an alternative pathway predicted to involve fewer enzymes. Our work represents a major step forward in elucidating the biosynthesis of fucoxanthin and understanding the evolution, biogenesis, and regulation of the photosynthetic machinery in algae.
Uridylation and the SKI complex orchestrate the Calvin cycle of photosynthesis through RNA surveillance of
TKL1
in Arabidopsis
Authors: Wang Xiaoyan , Kong Wenwen , Wang Yuan , Wang Jinhui , Zhong Luyao , Lao Kangwen , Dong Xianxin , Zhang Dingyu , Huang He , Mo Beixin , Yu Yu , Ren Guodong
Published: September 2022

RNA uridylation, catalyzed by terminal uridylyl transferases (TUTases), represents a conserved and widespread posttranscriptional RNA modification in eukaryotes that affects RNA metabolism. In plants, several TUTases, including HEN1 SUPPRESSOR 1 (HESO1) and UTP: RNA URIDYLYLTRANSFERASE (URT1), have been characterized through genetic and biochemical approaches. However, little is known about their physiological significance during plant development. Here, we show that HESO1 and URT1 act cooperatively with the cytoplasmic 3′–5′ exoribonucleolytic machinery component SUPERKILLER 2 (SKI2) to regulate photosynthesis through RNA surveillance of the Calvin cycle gene
TRANSKETOLASE 1
(
TKL1
) in
Arabidopsis
. Simultaneous dysfunction of
HESO1
,
URT1
, and
SKI2
resulted in leaf etiolation and reduced photosynthetic efficiency. In addition, we detected massive illegitimate short interfering RNAs (siRNAs) from the
TKL1
locus in
heso1 urt1 ski2
, accompanied by reduced
TKL1/2
expression and attenuated TKL activities. Consequently, the metabolic analysis revealed that the abundance of many Calvin cycle intermediates is dramatically disturbed in
heso1 urt1 ski2
. Importantly, all these molecular and physiological defects were largely rescued by the loss-of-function mutation in
RNA-DEPENDENT RNA POLYMERASE 6
(
RDR6
), demonstrating illegitimate siRNA-mediated
TKL
silencing. Taken together, our results suggest that HESO1- and URT1-mediated RNA uridylation connects to the cytoplasmic RNA degradation pathway for RNA surveillance, which is crucial for
TKL
expression and photosynthesis in
Arabidopsis
.
A scalable framework for the discovery of functional helicase substrates and helicase-driven regulatory switches
Authors: Delaleau Mildred , Eveno Eric , Simon Isabelle , Schwartz Annie , Boudvillain Marc
Published: September 2022

Helicases are ubiquitous motor enzymes that remodel nucleic acids (NA) and NA–protein complexes in key cellular processes. To explore the functional repertoire and specificity landscape of helicases, we devised a screening scheme—Helicase-SELEX (Systematic Evolution of Ligands by EXponential enrichment)—that enzymatically probes substrate and cofactor requirements at global scale. Using the transcription termination Rho helicase of
Escherichia coli
as a prototype for Helicase-SELEX, we generated a genome-wide map of Rho utilization (
Rut
) sites. The map reveals many features, including promoter- and intrinsic terminator-associated
Rut
sites, bidirectional
Rut
tandems, and cofactor-dependent
Rut
sites with inverted G > C skewed compositions. We also implemented an H-SELEX variant where we used a model ligand, serotonin, to evolve synthetic
Rut
sites operating in vitro and in vivo in a ligand-dependent manner. Altogether, our data illustrate the power and flexibility of Helicase-SELEX to seek constitutive or conditional helicase substrates in natural or synthetic NA libraries for fundamental or synthetic biology discovery.
Nanobodies and chemical cross-links advance the structural and functional analysis of PI3Kα
Authors: Hart Jonathan R. , Liu Xiao , Pan Chen , Liang Anyi , Ueno Lynn , Xu Yingna , Quezada Alexandra , Zou Xinyu , Yang Su , Zhou Qingtong , Schoonooghe Steve , Hassanzadeh-Ghassabeh Gholamreza , Xia Tian , Shui Wenqing , Yang Dehua , Vogt Peter K. , Wang Ming-Wei
Published: September 2022

Nanobodies and chemical cross-linking were used to gain information on the identity and positions of flexible domains of PI3Kα. The application of chemical cross-linking mass spectrometry (CXMS) facilitated the identification of the p85 domains BH, cSH2, and SH3 as well as their docking positions on the PI3Kα catalytic core. Binding of individual nanobodies to PI3Kα induced activation or inhibition of enzyme activity and caused conformational changes that could be correlated with enzyme function. Binding of nanobody Nb3-126 to the BH domain of p85α substantially improved resolution for parts of the PI3Kα complex, and binding of nanobody Nb3-159 induced a conformation of PI3Kα that is distinct from known PI3Kα structures. The analysis of CXMS data also provided mechanistic insights into the molecular underpinning of the flexibility of PI3Kα.
Hegemony, Discourse, and Political Strategy
Authors: Jacobs Thomas
Published: September 2022

Hegemony, Discourse, and Political Strategy revisits a question that has long fascinated socialists, progressives, democrats, Greens, and Marxists – how do left-wing forces win at politics? Thirty-five years ago, Ernesto Laclau and Chantal Mouffe tackled this puzzle in ground-breaking fashion, by drawing on a signature blend of linguistics, Marxist theory, and poststructuralism that came to be known as post-Marxist Discourse Theory (PDT). This book takes up the legacy of Laclau and Mouffe, and elaborates PDT into a full-fledged theory of political strategy for the first time. It argues that post-Marxism provides the foundations for a form of discourse analysis that can explain how political strategies play out as well as why they fail or succeed. Its empirical potential to illuminate the dynamics of hegemonic struggles is demonstrated through a case study focusing on the contestation and politicization of EU trade policy in the European Parliament.
Substance Use–Related Continuing Education Course Objectives: Alignment with Professional Competencies
Authors: Finnell Deborah S. , Soltis-Jarrett Victoria , Bratberg Jeffrey , Muzyk Andrew , Liu Yifei , Edens Ellen , Seale J. Paul , Mattingly Jill , Schnurman Kristen , Osborne-Leute Victoria , Zweben Allen , Cary Ann , Moore Brent A.
Published: September 2022

Background: Novel educational efforts are needed to prepare the current and future interprofessional health care workforce to address the range of substance use–related health problems. A 6-module massive open online course (MOOC) was developed to provide education to health professionals of various disciplines on the fundamentals of substance use–related treatment. The purpose of this project was to match course objectives to substance use–related competencies for 5 disciplines: nurses, pharmacists, physicians, physician assistants (PA), and social workers. Methods: Content expert raters within each discipline determined what Association for Multidisciplinary Education and Research in Substance use and Addiction (AMERSA) core competencies were matched to each objective for the 6 modules of the MOOC. The number of objectives across the 6 modules was summated. Results: All nursing and social work competencies were mapped to the course objectives. For physicians, PAs, and pharmacists, the proportions of knowledge-based competencies that mapped to the course objective were 58%, 76%, and 80%, respectively, and proportions of skill-based competencies that mapped to the course objective were 88%, 83%, and 75%, respectively. For those 3 groups, 100% of attitude-based competencies mapped to the course objective. Conclusions: The competency-based mapping with the MOOC objectives supports the interprofessional design of the course and discipline-specific competencies needed to promote the best outcomes for patients.
A consistent approach to the path integral formalism of quantum mechanics based on the maximum length uncertainty
Authors: Pramanik Souvik
Published: September 2022

We have developed a proper path integral formalism consistent with the deformed version of the quantum mechanics that contains a maximum observable length scale at the order of the cosmological particle horizon, existing in cosmology. We have started by modifying the classical mechanics which shows non-minimal effects on the equation of motion of a particle. Next, we have provided representation of the deformed quantum mechanical algebra. With this algebra in hand, we have calculated the general form of the path integral propagator in this deformed background. Thereafter, as a most simple case, we have built up the explicit form of the free particle propagator. The modifications to the free particle propagator show some non-trivial effects in this case. Our formalism can be applied to analyze the quantum properties and observations emerging in the context of cosmology.
Tetragonal distortion modified magnetism and anomalous Hall effect of Mn2CoAl Heusler alloys through Ar ion irradiation
Authors: Chen Peng , Yan Zhongjie , Liu Xu , Cao Dianliang , Gao Daqiang , Gao Cunxu
Published: September 2022

Tetragonal Heusler alloys have attracted increasing interest due to their great scientific and technological applications in spintronics. However, the crystal structures of most Heusler alloys are cubic. One feasible method to obtain tetragonal Heusler alloy is to manipulate the out-of-plane (OOP) distortion of cubic Heusler alloys. In this work, we report the ion irradiation-induced tetragonal distortion in Mn2CoAl Heusler films. The OOP lattice constant continuously increases from 5.84 to 6.09 Å, while the in-plane lattice constant remains nearly unchanged. Magnetic measurements show that saturation magnetization at 50 K decreases from 258 emu cc−1 to 167 emu cc−1 under Ar ion irradiation. Transport measurements show that the longitudinal resistivity decreases with increasing irradiation doses, and the anomalous Hall resistivity changes from negative to positive. Moreover, it is found that hump-like anomalies can be observed in the Hall resistivity loops at the irradiation dose of 1

×

10

14

and 1

×

10

15

cm−2, which are attributed to the irradiation-induced inhomogeneous magnetism in the surface and interface parts. This work demonstrates the considerable tunability of the structure, magnetism and transport properties of Mn2CoAl Heusler alloys by Ar ion irradiation.