bluuebunny/crossref_metadata_2025 huggingface dataset:
Galactic center gamma-ray production by cosmic rays from stellar winds and Sgr A East
Authors: Scherer Andrés , Cuadra Jorge , Bauer Franz E.
Published: February 2022

Context. The High Energy Stereoscopic System, the Major Atmospheric Gamma-ray Imaging Cherenkov Telescope, and the Very Energetic Radiation Imaging Telescope Array System have observed diffuse gamma-ray emission strongly correlated with the central molecular zone in the Galactic center. The most accepted scenario to generate this emission is via a hadronic interaction between cosmic rays (CRs) and ambient gas, where CRs are accelerated from a central and continuous source of 1 PeV protons.

Aims. We explore the influence of the three-dimensional (3D) shape of the central molecular zone on the indirect observation of the CR energy density via gamma-ray detection.

Methods. We simulated synthetic gamma-ray maps using a CR diffusion model with spherical injection, one isotropic diffusion coefficient, no advection, and mono-energetic particles of 1 PeV. Also, we used two different 3D gas distributions considering the observed gas column density, both with and without an inner cavity.

Results. We find that when using a persistent CR source, a disk-like gas distribution is needed to reproduce the existing CR indirect observations. This is in agreement with the continuous gas distribution implied by some dynamical models and studies based on the comparison of emission and absorption molecular lines. However, it contradicts several models of the central molecular zone, which imply that this structure has a significant inner cavity. This tension can be reconciled by an additional, impulsive CR injection.

Conclusions. If the central molecular zone has a cavity, a composite CR population, coming from the stellar winds of the Wolf-Rayet stars in the central 0.5 pc and the supernova Sgr A East, produces a good match to the observed gamma-ray morphology in the Galactic center.
Transit timing variations of AU Microscopii b and c
Authors: Szabó Gy. M. , Garai Z. , Brandeker A. , Gandolfi D. , Wilson T. G. , Deline A. , Olofsson G. , Fortier A. , Queloz D. , Borsato L. , Kiefer F. , Lecavelier des Etangs A. , Lendl M. , Serrano L. M. , Sulis S. , Ulmer Moll S. , Van Grootel V. , Alibert Y. , Alonso R. , Anglada G. , Bárczy T. , Barrado y Navascues D. , Barros S. C. C. , Baumjohann W. , Beck M. , Beck T. , Benz W. , Billot N. , Bonfanti A. , Bonfils X. , Broeg C. , Cabrera J. , Charnoz S. , Collier Cameron A. , Csizmadia Sz. , Davies M. B. , Deleuil M. , Delrez L. , Demangeon O. , Demory B.-O. , Ehrenreich D. , Erikson A. , Fossati L. , Fridlund M. , Gillon M. , Güdel M. , Heng K. , Hoyer S. , Isaak K. G. , Kiss L. L. , Laskar J. , Lovis C. , Magrin D. , Maxted P. F. L. , Mecina M. , Nascimbeni V. , Ottensamer R. , Pagano I. , Pallé E. , Peter G. , Piotto G. , Pollacco D. , Ragazzoni R. , Rando N. , Rauer H. , Ribas I. , Santos N. C. , Sarajlic M. , Scandariato G. , Ségransan D. , Simon A. E. , Smith A. M. S. , Sousa S. G. , Steller M. , Thomas N. , Udry S. , Verrecchia F. , Walton N. , Wolter D.
Published: February 2022

Here we report large-amplitude transit timing variations (TTVs) for AU Microcopii b and c as detected in combined TESS (2018, 2020) and CHEOPS (2020, 2021) transit observations. AU Mic is a young planetary system with a debris disk and two transiting warm Neptunes. A TTV on the order of several minutes was previously reported for AU Mic b, which was suggested to be an outcome of mutual perturbations between the planets in the system. In 2021, we observed AU Mic b (five transits) and c (three transits) with the CHEOPS space telescope to follow-up the TTV of AU Mic b and possibly detect a TTV for AU Mic c. When analyzing TESS and CHEOPS 2020−2021 measurements together, we find that a prominent TTV emerges with a full span of ≥23 min between the two TTV extrema. Assuming that the period change results from a periodic process –such as mutual perturbations– we demonstrate that the times of transits in the summer of 2022 are expected to be 30−85 min later than predicted by the available linear ephemeris.
Concise Synthesis of (S)-7-Hydroxy-5-aza-8a-epi-d-swainsonine from a d-Erythrose Derivative
Authors: Sousa Cristina E. A. , Salgueiro Daniela A. L. , Alves Maria J.
Published: February 2022

A five-step synthesis of (S)-7-hydroxy-5-aza-8a-epi-d-swainsonine [(3S,4S,4aS,5S,6R)-octahydropyrrolo[1,2-b]pyridazine-3,4,5,6-tetraol] was accessed in good overall yield from readily available d-erythrosyl benzylidene acetal buta-1,3-diene. The key step of the reaction sequence is a full stereoselective Diels–Alder cycloaddition between­ the diene and dienophile: diethyl azodicarboxylate (DEAD) or di-tert-butyl azodicarboxylate (DBAD). The cycloadducts were further transformed into the title 5-aza-indolizidine. Optimized procedures were obtained for the synthesis of intermediates and products.
Synthesis of Structurally Defined Nitroxide Spin-Labeled Glycolipids as Useful Probes for Electron Paramagnetic Resonance (EPR) Spectroscopy Studies of Cell Surface Glycans
Authors: Guo Zhongwu , Yan Xin
Published: February 2022

Four glycolipids carrying different glycans and a nitroxide free radical spin at the glycan non-reducing end were designed and synthesized from free glucose and maltooligosaccharides by an efficient and streamlined synthetic strategy. The main features of this synthetic strategy include regioselective functionalization of the free carbohydrates and coupling of the radical spin label with functionalized free glycans as the last synthetic step. These glycolipids are useful probes for the study of cell surface glycans by electron paramagnetic resonance spectroscopy. Moreover, the key synthetic intermediates, free glycolipids carrying a flexible azido group at the glycan non-reducing end, are widely useful platforms for accessing glycolipids with other molecular labels.
Real-World Experience of Treating Young Adult Patients with Breast Cancer from a Single Center in Southern India
Authors: Iyer Priya , Radhakrishnan Venkatraman , Krishnamurthy Arvind , Dhanushkodi Manikandan , V. Sridevi , Ananthi Balasubramanian , Selvaluxmy Ganeshraja
Published: February 2022

Background Breast cancer in young adults is rare and accounts for 5 to 6% of all cancers in this age group. We conducted the present study to look at the demographic features, clinical presentation, and outcomes in this group of patients treated at our center.

Patients and Methods The study included breast cancer patients between the age of 15 and 30 years treated at our institute from January 2009 to December 2016. Data were analyzed retrospectively from case records. Event-free survival (EFS) and overall survival (OS) were calculated using the Kaplan–Meier method.

Results Young adult breast cancers were reported in 145 out of 6,000 patients (2.41%) diagnosed with breast cancer in the study period. The median age of the patients was 29 years (range: 21–30 years). Stage I, II, III, and IV was observed in 3.4, 33.7, 46.2, and 16.5% of patients, respectively. The median follow-up was 45 months (range: 1.7–128.1 months). The 5-year EFS and OS for stage I, II, III, and IV was 100, 74.5, 47.9, and 0% and 100, 90.8, 55.1, and 0%, respectively. On univariate analysis, stage of the disease and pregnancy-associated breast cancers were found to have a significant association with decreased EFS and OS (p < 0.001, p = 0.008 and p < 0.001, p = 0.001, respectively). On multivariate analysis, stage of disease and pregnancy-associated breast cancers remained significant predictors of EFS and OS.

Conclusion Breast cancers in young adults are rare but need to be diagnosed at an early stage to improve survival. Pregnancy-associated breast cancers need to be managed optimally without delay owing to their aggressive tumor biology.
Writing a Case Report in Pediatric Surgery: A Comprehensive Guideline
Authors: Feng Xiaoyan , Wagner Richard , Rogers Silvia , Lacher Martin , Aubert Ophelia
Published: February 2022

An effective case report delivers clear and valuable clinical or surgical information to the medical community. Case reports dealing with pediatric surgical issues raise the medical community's awareness of rare diseases, unusual presentations of common disorders, or novel surgical or nonsurgical treatment approaches. Thus, case reports contribute substantially to medical advance by sharing remarkable or unexpected findings. For this reason, case reports should be prepared with vigilance, and current conventions on good medial writing practice should be observed. This guideline aims to assist clinicians and surgeons in the successful publishing of a compelling case report in pediatric surgery that is read and understood by the intended audience.
Anti-GFAP Antibody-Associated Hypertrophic Pachymeningitis
Authors: Tan Chengbing , Zhong Min , Yao Zhengxiong , Hong Siqi , Jiang Li , Jiang Yan
Published: February 2022

Background Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy is an inflammatory central nervous system (CNS) disorder that usually presents as steroid responsive encephalitis, meningitis, myelitis, or meningoencephalomyelitis. Hypertrophic pachymeningitis (HP) is an uncommon disorder that causes a localized or diffuse thickening of the dura mater. Depending on the etiology, HP can be idiopathic or secondary to a wide variety of other diseases. There are no reports of autoimmune GFAP astrocytopathy presenting as HP.

Methods In this case report, we describe a rare case of pediatric HP possibly associated with anti-GFAP antibody.

Results A 13-year-old previously healthy girl presented with headache for nearly 8 months with left-sided peripheral facial palsy and left-sided abductor nerve palsy in the second month of course. Magnetic resonance imaging (MRI) of the brain revealed contrast enhancement of hypertrophic dura mater. Anti-GFAPα antibodies were positive in serum and cerebrospinal fluid. The patient improved clinically after steroid treatment with partial resolution of abnormal intracranial MRI lesions.

Conclusion The present study suggests that HP may be one of the clinical phenotypes for autoimmune GFAP astrocytopathy or GFAP antibody is a biomarker for HP.
The self-reported human health effects associated with heat exposure in Agincourt sub-district of South Africa
Authors: Manyuchi Albert Edgar , Vogel Coleen , Wright Caradee Y. , Erasmus Barend
Published: February 2022

Exposure to heat and heatwaves are associated with mortality and may amplify morbidities. In a climate change context, projections suggest temperatures will likely rise in the foreseeable future. Our paper assesses the current knowledge on human health effects of heat exposure and gathered local knowledge of heat-health effects in a rural area of the Agincourt sub-district of South Africa. Existing, peer-reviewed published literature on heat effects on human health as well as heat-health indicators was reviewed. Interviews and structured observations to collect data on heat effects on human health in Agincourt sub-district were conducted. The Lancet Countdown heat-related indicators were applied as a framework against which to discuss our findings. A total of 93 participants who lived in Agincourt sub-district for 5 years and more were interviewed. Participants reported that temperatures, especially summertime temperatures, had been rising over the past years. Health effects of heat were deemed more apparent in relation to morbidity. Heatwaves were not easily comprehensible as singular ‘events’, and their effects were poorly understood. The population groups disproportionately affected by heat included infants, the elderly, those living with disability and outdoor workers. High ambient temperatures were deemed to be associated with reduced labour productivity of outdoor workers. Community-level perceptions of heat impacts on health were mainly related to illnesses and diseases, with no understanding of mortality risk. Future health awareness campaigns that encompass the full range of heat-health impacts are essential to reduce vulnerability, morbidity, and mortality. Our study provided location-specific, qualitative, and indicator-aligned data for a geographic area expected to undergo significant heat stress in the future. The study findings have significant research, policy, and practice implications in similar resource-limited settings.
Disorder is not necessarily a disadvantage in photonics
Authors: Piccone Ashley
Published: February 2022

Many photonic devices can employ structural disorder to enhance performance, enable new functionalities, and reduce cost.
Sources for constellation errors in modulated dispersion interferometers
Authors: Brunner K. J. , Knauer J. , Meineke J. , Cu Castillo H. I. , Hirsch M. , Kursinski B. , Stern M. , Wolf R. C. ,   W7-X Team
Published: February 2022

Dispersion interferometry (DI) is being employed on an increasing number of fusion experiments to measure the plasma density with a minimal sensitivity to vibrations. DIs employed in high-density experiments use phase modulation techniques up to several hundred kilohertz to enable quadrature detection and to be unaffected by variations of the signal amplitude. However, the evaluation of the temporal interferogram can be a significant source for phase errors and does not have an established processing method. There are two non-approximation-based methods currently in use: one using the ratio of amplitudes in the signal’s Fourier spectrum and the other using its sectioned integration. Previously, the methods could not be used simultaneously since they differ in their respective calibration point. In this paper, we present a technique to use both phase evaluation methods simultaneously using quadrature correction methods. A comparison of their strengths and weaknesses is presented based on identical measurements indicating one to be more reliable in a more static measurement scenario, while the other excels in highly dynamic ones. Several comparative experiments are presented, which identify a significant error source in the phase measurement induced by polarization rotation. Since the same effect may be induced by Faraday rotation, the results may have direct consequence on the design of the ITER dispersion interferometer/polarimeter as well as the European DEMO’s interferometer concept.
Scaffolds with isolated carbon nanowalls promote osteogenic differentiation through Runt-related transcription factor 2 and osteocalcin gene expression of osteoblast-like cells
Authors: Ichikawa Tomonori , Ishikawa Kenji , Tanaka Hiromasa , Shimizu Naohiro , Hori Masaru
Published: February 2022

Carbon nanowalls (CNWs) with average wall-to-wall distances ranging from 100 to 3300 nm were synthesized using a radical injection plasma-enhanced chemical vapor deposition system. Application of a negative high voltage to the growth substrate using an inductor energy storage (IES) circuit provided CNWs with wall-to-wall distances depending on the nano-second pulse voltage of the IES circuit. Sparse isolated CNWs with average wall-to-wall distances of 700 nm were used for culturing Saos-2 cells. These cells showed better adhesion than the control after 2 days’ incubation and enhanced gene expression of the osteogenic differentiation genes Runt-related transcription factor 2 (Runx2) and osteocalcin after 10 days’ incubation. Sparse isolated CNW scaffolds hold promise for regulating the differentiation of osteoblast-like cells.
Photothermal phenomenon: Extended ideas for thermophysical properties characterization
Authors: Liu Jing , Han Meng , Wang Ridong , Xu Shen , Wang Xinwei
Published: February 2022

The photothermal phenomenon involves material photon heating in the form of continuous waves, modulated waves, or pulses. The resulting temperature rise carries very rich information about the material's structures and thermophysical properties. This review is constructed to cover some of the extended ideas of the photothermal phenomenon for measuring a material's thermophysical properties and interface thermal conductance/resistance. For frequency-domain photothermal phenomena, the photoacoustic (PA) and photothermal radiation (PT) techniques provide great ways to measure coatings and suspended samples, which can also be measured using the laser flash and time-domain thermoreflectance (TDTR) techniques. Thermal probing based on electrical thermal sensing is successfully implemented in the transient photo-electro-thermal (TPET) and pulsed laser-assisted thermal relaxation (PLTR) techniques, which significantly extend the capability of laser flash technique to micro/nanoscale 1D structures. The energy transport state-resolved Raman (ET-Raman) is distinct from traditional techniques in its material-specific thermal sensing capability and integral way of ultrafast thermal sensing. Detailed physics discussions are provided for all these techniques, including their advantages and limitations. Still, large development rooms exist for the relatively new techniques, including TPET, PLTR, and ET-Raman. These include measurements under extreme situations, sensitivity improvement, and distinguishing conjugated physical processes.
Thermocapillary droplet migration in a vertical temperature gradient controlled by thermal radiations
Authors: Wu Zuo-Bing
Published: February 2022

Thermocapillary migration of a droplet in a vertical temperature gradient controlled by uniform and non-uniform thermal radiations is theoretically analyzed and numerically investigated. A non-dimensionlized thermal radiation number is proposed to quantitatively depict the intensity ratio of the thermal radiation flux to the uniform temperature gradient. From the momentum and energy equations at zero limits of Reynolds and Marangoni numbers, analytical results for the uniform and non-uniform thermal radiations are determined. The steady migration velocity raises with the increasing of the thermal radiation number. By using the front-tracking method, it is observed that thermocapillary droplet migration under the uniform thermal radiation at moderate Marangoni and moderate thermal radiation numbers reaches a steady process. The steady migration velocity decreases with the increasing of Marangoni number and increases with the increasing of thermal radiation number. Moreover, the intensity of thermal energy transferred from the interface to both fluids depends on the volume heat capacity ratio. For the larger/smaller volume heat capacity ratio, more heat is transferred into the continuous phase fluid/the droplet. Furthermore, when the uniform thermal radiation is replaced by the non-uniform ones, the time evolutions, the structures of temperature fields, and parameter dependencies of thermocapillary droplet migration at moderate Marangoni and moderate thermal radiation numbers remain qualitatively unchanged. This study provides a profound understanding of thermocapillary droplet migration in a vertical temperature gradient controlled by thermal radiations, which is of great significance for practical applications in microgravity and microfluidic fields.
Recent progress of two-dimensional metallic transition metal dichalcogenides: Syntheses, physical properties, and applications
Authors: Song Luying , Li Hui , Zhang Yanfeng , Shi Jianping
Published: February 2022

Two-dimensional (2D) metallic transition metal dichalcogenides (MTMDCs) are emerging as an appealing class of materials for a wide range of research topics, including electronics, spintronics, and energy-related fields, in view of their unique physical and chemical properties. Notably, the controlled synthesis of such promising materials is a prerequisite. In this Perspective, we review the up-to-date advances regarding the syntheses and physical properties of 2D MTMDCs, as well as their multifunctional applications. First, a variety of synthetic strategies of 2D MTMDCs, such as chemical exfoliation, chemical vapor transport, atomic layer deposition, molecular beam epitaxy, and chemical vapor deposition, are systematically summarized. Second, the fundamental physical properties of 2D MTMDCs are introduced, including charge density wave order, ferromagnetism, and superconductivity. Third, the versatile applications of 2D MTMDCs in electronic devices and energy-related fields are discussed. Finally, the challenges about the exploration of controlled syntheses, interesting physical issues, and multifunctional applications are highlighted, and future directions are also proposed. We believe that this Perspective is comprehensive and insightful for the controllable syntheses, physical property characterizations, and application exploitations of 2D MTMDCs.
Accurate demonstrating of the interactions of two long waves with different dispersion relations: Generalized Hirota–Satsuma couple KdV equation
Authors: Zhang Jianmei , Lu Dianchen , Salama Samir A. , Khater Mostafa M. A.
Published: February 2022

In this study, the generalized formula of the Hirota–Satsuma coupled KdV equation derived by Hirota and Satsuma in 1981 [Hirota and Satsuma, Phys. Lett. A 85, 407−408 (1981)] is analytically and semi-analytically investigated. This model is formulated to describe the interaction of two long undulations with diverse dispersion relations; that is why it is also known with a generalized model of the well-known KdV equation. The generalized Kudryashov and Adomian decomposition methods construct novel soliton wave and semi-analytical solutions. These solutions are represented in some distinct graphs to show the waves’ interactions. In addition, the accuracy of solutions is verified by comparing the obtained analytical and semi-analytical solutions that show the matching between them. All solutions are checked by putting them back into the original model through Mathematica 12.
Role of lithium intercalation in fluorine-doped tin oxide thin films: Ab initio calculations and experiment
Authors: Perez Israel , Sosa Victor , Gamboa Fidel , Enriquez-Carrejo Jose Luis , Mixteco Sanchez Juan Carlos
Published: February 2022

Using a combination of experimental techniques and density functional theory (DFT) calculations, the influence of lithium insertion on the electronic and electrochemical properties of fluorine-doped SnO2 (FTO) is assessed. For this purpose, we investigate the electrochromic behavior of a commercial FTO electrode embedded in a solution of lithium perclorate (LiClO4). The electrochromic properties are evaluated by UV–vis spectroscopy, cyclic voltammetry, and chronoamperometry. These tests show that FTO exhibits electrochromism with a respectable coloration efficiency (η = 47.9 cm2/C at 637 nm). DFT study indicates that lithium remains ionized in the lattice, raising the Fermi level about 0.7 eV deep into the conduction band. X-ray photoelectron spectroscopy (XPS) is used to study chemical bonding and oxidation states. XPS analysis of the Sn 3d core levels reveals that lithium insertion in FTO induces a shift of 350 meV in the Sn 3d states, suggesting that lithium is incorporated into the SnO2 lattice.
Targeting stem-loop 1 of the SARS-CoV-2 5′ UTR to suppress viral translation and Nsp1 evasion
Authors: Vora Setu M. , Fontana Pietro , Mao Tianyang , Leger Valerie , Zhang Ying , Fu Tian-Min , Lieberman Judy , Gehrke Lee , Shi Ming , Wang Longfei , Iwasaki Akiko , Wu Hao
Published: February 2022

Significance

The COVID-19 pandemic and the ever-evolving variants of SARS-CoV-2 are taking a toll on human health. Despite the successful rollout of vaccines, effective therapies are still urgently needed. Our studies here showing that Nsp1 selectively blocks translation of host but not viral proteins by proper coordination of its N- and C-terminal domains to advance our understanding on SARS-CoV-2 pathogenesis. Our finding that stem-loop 1, a highly conserved sequence in the SARS-CoV-2 5′ UTR, is necessary and sufficient for bypassing Nsp1-mediated shutdown led to the design of antisense oligonucleotides targeting this sequence that make viral translation susceptible to Nsp1 shutdown, interfere with viral replication, and protect SARS-CoV-2–infected mice. This strategy of turning SARS-CoV-2’s own virulence against itself could be harnessed therapeutically.
Alternatives to QUD
Authors: Ozerov Pavel
Published: February 2022

The paper critically examines some central principles of the Question Under Discussion (QUD) framework and ultimately explores the concept of ‘question’, central to QUD-models. It demonstrates how fine-grained, interactionally informed analyses of language-specific categories can reveal building blocks of interaction and explain the sources of the observed information- and discourse-structuring interpretations (such as update, contrast and more). Employing data from Anal Naga (Trans-Himalayan, India), it proceeds to a fine-grained analysis of the notion of ‘question’. The decomposition of ‘questions’ into smaller building blocks similarly reveals how diverse categories and discourse processes can trigger the interpretation of an information request. These findings and additional theoretical arguments suggest that QUD-models are problematic for various reasons: such models are non-parsimonious as they add superfluous extra layers to explain the observations; the explanatory apparatus is circular, as the extra layers are derived from within the explananda but regarded as underlying explanatory factors; and the models gloss over the actual factors by channelling them into cover terms prematurely regarded as primitive. Finally, since ‘question’ does not constitute a primitive concept but is a product of diverse discourse processes, discourse cannot be modelled on this foundation.
Online discourses of ‘homosexuality’ and religion
Authors: Jantunen Jarmo Harri , Kytölä Samu
Published: February 2022

This article examines Finnish online forum discussions where religion and discourses of ‘homosexuality’ are connected in various ways. Previous research (e.g.Jantunen 2018a) shows that in Finnish online discussions where sexual minorities are the topic, religion stands out as a significant feature – particularly in discourses on ‘homosexuality’. Via corpus-assisted discourse analysis (CADS), the present study adds to previous knowledge on this subject by qualitatively analyzing the occurrences of certain keywords in the Finnish societal context – one in which immigration and the visibility of both Islam and sexual minorities are perceived to have increased. The analysis found four interrelated key discourses in these online discussions: (1) Islamization as an alleged threat to gay people (in the data: ‘homosexuals’); (2) the alleged indifference/ignorance of people to Islam’s stance against sexual minorities; (3) relativist discourse(s) claiming all fundamentalists to be similar; and (4) othering – including for instance, the verbal stylization of Muslims as being particularly hypersexual.
Microstructure, high-temperature oxidation and molten salt corrosion behaviour of CoCrFeNiAl0.1-RE HEA
Authors: Guo Yuhang , Chen Pan , Dai Yibo , Xiang Hongfu
Published: February 2022

In this study, CoCrFeNiAl0.1-RE HEA was melted using a magnetic levitation melting furnace, resulting in a single-phase FCC solid solution structure with a coarse irregular equiaxed grain morphology in the period. The oxidation experiment results showed that the samples’ oxidation kinetics followed the parabolic rate law, and the oxidation product species increased with increasing temperature. High temperatures primarily revealed Cr2O3, (Cr, Fe)2O3, and other spinel phases such as NiFe2O4, CoCr2O4, and CoFe2O4. Under the oxide film, Al-rich striped raised phases were observed. According to the elemental divisions, the oxide film will be damaged to expose the FCC matrix in molten salt corrosion, and the film can be divided into four layers: peeling layer, newly oxidised-corroded outer layer, transition layer, and matrix. As molten salt is destroyed, cavities and channels appear in the film, allowing molten salt and oxygen to infiltrate and accelerate the oxidation and corrosion of the sample.
Formation of electronic coherences in conical intersection-mediated dynamics
Authors: Neville Simon P , Stolow Albert , Schuurman Michael S
Published: February 2022

We consider the formation of vibrationally-induced transient electronic coherences driven by conical intersection (CI)-mediated population transfer between two electronic states. By invoking fundamental symmetry arguments, we identify several important factors which modulate the magnitude of these electronic coherences. We consider the sub-cases where the two electronic states have either the same or different Abelian point group symmetry at the Franck–Condon geometry. For the different symmetry case, due to the inherent symmetry of the molecular Hamiltonian, significant electronic coherences are unlikely to form. In contrast, for electronic states of the same symmetry, large magnitude electronic coherences can form. However, the magnitude of these coherences is highly dependent on the topography of the CI. These results offer a guide to experimental studies of electronic coherences which may (or may not) be induced by nuclear motion in the vicinity of a CI, as well as to ab initio simulations which are employed to simulate them.
Flow field tomography with uncertainty quantification using a Bayesian physics-informed neural network
Authors: Molnar Joseph P , Grauer Samuel J
Published: February 2022

We report a new approach to flow field tomography that uses the Navier–Stokes and advection–diffusion equations to regularize reconstructions. Tomography is increasingly employed to infer 2D or 3D fluid flow and combustion structures from a series of line-of-sight (LoS) integrated measurements using a wide array of imaging modalities. The high-dimensional flow field is reconstructed from low-dimensional measurements by inverting a projection model that comprises path integrals along each LoS through the region of interest. Regularization techniques are needed to obtain realistic estimates, but current methods rely on truncating an iterative solution or adding a penalty term that is incompatible with the flow physics to varying degrees. Physics-informed neural networks (PINNs) are new tools for inverse analysis that enable regularization of the flow field estimates using the governing physics. We demonstrate how a PINN can be leveraged to reconstruct a 2D flow field from sparse LoS-integrated measurements with no knowledge of the boundary conditions by incorporating the measurement model into the loss function used to train the network. The resulting reconstructions are remarkably superior to reconstructions produced by state-of-the-art algorithms, even when a PINN is used for post-processing. However, as with conventional iterative algorithms, our approach is susceptible to semi-convergence when there is a high level of noise. We address this issue through the use of a Bayesian PINN, which facilitates comprehensive uncertainty quantification of the reconstructions, enables the use of a more intuitive loss function, and reveals the source of semi-convergence.
Development of a magnetorheological elastomer rubber joint with fail-safe characteristics for high-speed trains
Authors: Gong Ning , Yang Jian , Li Zhixiong , Ning Donghong , Jin Hu , Gong Xinglong , Li Weihua , Zhang Shiwu , Sun Shuaishuai
Published: February 2022

The stiffness of the train’s rubber joint at the primary suspension system has a crucial influence on the operation stability and curve-passing performance. As traditional rubber joint only provides unadjustable parameters, they cannot meet the conflicting stiffness requirements when the train is running at high speed on straight track and passing through the curve track. To solve this problem, this paper proposed a new rubber joint with fail-safe characteristics based on magnetorheological elastomer (MRE). The joint stiffness is controlled by a hybrid magnetic field generated by permanent magnets and electromagnets. With this hybrid magnetic field, the initial stiffness of the MRE joint can be designed to be hard so as to suppress the hunting motions and vibrations of wheelsets and thus keep the trains’ high-speed stability; furthermore, the stiffness can decrease by energizing the electromagnets when passing through a curve track. With this characteristic, the joint can guarantee the safety of the train at high operation speed even when the joint control system fails. The prototype of the MRE joint was fabricated and assembled. Stiffness controllability of the MRE joint was tested using a Material Testing Systems machine. The result reveals that the stiffness of this MRE joint can be controlled effectively. According to the testing results, a new phenomenological model was built to predict the joint’s dynamic performance. Then this established model was integrated into dynamic models of trains to numerically evaluate the new joint’s influence on the train’s stability and trafficability. The evaluation result shows that the proposed MRE joint is fully effective on providing controllable stiffness to satisfy the conflicting stiffness requirement with fail-safe characteristics.
Study on the rheological and polishing properties of electromagnetic two-phase composite particles with abrasive characteristics
Authors: Chen Zhijun , Pan Jisheng , Yan Qiusheng , Huang Zhanliang , Zhang Fenglin , Chen Shumei
Published: February 2022

Electromagnetic composite rheological polishing (EMRP) is a new ultra-precision machining technology that combines electro-rheological polishing (ERP) and magneto-rheological polishing (MRP). The key technology of the polishing method is the preparation of electromagnetic composite rheological fluid (EMRF) with both ERP and MRP, especially the preparation of composite particles with electro- and magneto-rheological effects. In this study, the EMRF was prepared by using electromagnetic two-phase particles with abrasive characteristics. The electromagnetic two-phase composite particles are synthesized in two steps: the coupling method and sol-gel method. The two-step method successfully prepared the electromagnetic two-phase composite particles with nano-diamond particles embedded randomly on the surface. The electro-rheological shear stress of EMRF can reach 160.7 Pa when the test parameter voltage is 2.5 kV, and magneto-rheological shear stress of EMRF can reach 4076 Pa when the electromagnet excitation current is 3 A. When a fused silica glass is polished under a single magnetic field, the material removal depth reaches a maximum of 2.7 μm at a radius of 13.5 mm. Under the action of the electromagnetic compound field, the removal profile of the work-piece is smoother, and the material removal depth reaches the maximum value of 2.1 μm at a radius of 10.5 mm. This proves that the stiffness distribution of the polishing pad under the electromagnetic composite field is more dispersed than that under a single field. Therefore, the distribution of electromagnetic two-phase composite particles can be controlled by applying an electromagnetic composite field, which provides a good foundation for the abrasive control technology of EMRP.
Far-field subwavelength imaging by harnessing the single-mode resonance and sparsity
Authors: Mu Yadong , Yu Gaokun , Wang Ning
Published: February 2022

Although far-field superlenses and resonant metalenses provide a way to obtain the far-field subwavelength imaging through the resonant excitation of multiple surface wave modes, the high sensitivity of these resonant modes to the absorption loss hinders their practical applications. To break this limitation, only a single resonant mode which survives the absorption loss is chosen for imaging, where a reconstruction algorithm based on the sparsity is adopted to compensate for the reduction of the number of degrees of freedom. An experiment is carried out to verify a far-field subwavelength imaging of two home-made sources, and it is found that the two imaged sources can be well resolved by using multiple frequencies near the fifth resonant mode.
Doubling off-axis electron cyclotron current drive efficiency via velocity space engineering
Authors: Chen Xi , Petty C.C. , Lohr J. , Su D. , Prater R. , Cengher M. , Austin M. , Holcomb C. , Lao L. , Pinsker R.I. , Victor B. , Zeng L.
Published: February 2022

For the first time, experiments on the DIII-D tokamak have demonstrated electron cyclotron current drive with more than double the conventional efficiency by tailoring the wave–particle interactions in velocity space using a novel ‘top launch’ geometry. Steering the EC waves to propagate nearly parallel to the resonance drives current more efficiently by (1) selective damping on electrons with higher parallel velocity v||, and (2) longer absorption path to compensate for inherently weaker absorption at higher v||. Experiments using a fixed-injection top launch system find an optimal velocity space interaction for maximum current drive efficiency at ρ ∼ 0.5 where the ease of drawing out a high v|| electron tail is balanced by sufficient absorption.
Inter-machine plasma perturbation studies in EU-DEMO-relevant scenarios: lessons learnt for prediction of EM forces during VDEs
Authors: Sias G. , Minucci S. , Lacquaniti M. , Lombroni R. , Fanni A. , Calabrò G. , Cannas B. , Pisano F. , Siccinio M. , Ramogida G. , Giorgetti F. , Fanelli P. , Maviglia F. , the EUROfusion MST1 Team  , JET EFDA Contributors
Published: February 2022

To support the deployment of the DEMO wall protection strategy, the development of comprehensive analyses is essential to understand the implications of transient perturbations on plasma shape control and on vertical stability, some of the most critical aspects to be considered in elongated plasmas. The design activities of the DEMO limiter structures require a deep understanding of the effects induced by transient plasma perturbations coupled with one of the most severe load conditions to occur in tokamaks, the vertical displacement event (VDE). Since electromagnetic (EM) loads during VDE phases are among the DEMO limiter’s design drivers, this study focuses on predictive simulations of the final plasma position and of EM loads following a VDE. For this purpose, a multi-tokamak study, supported by the construction of an inter-machine database containing experimental transient plasma perturbations and VDEs from JET and ASDEX Upgrade (AUG), has been carried out. It aims to characterize some transient plasma perturbations that may lead to high control efforts by the vertical stability system in terms of variations of the plasma’s internal parameters and vertical displacements. Consequently, such experimental transient plasma perturbations have been properly scaled to DEMO reference geometries with different magnetic configurations, to be simulated in terms of plasma dynamical behaviour by means of MAXFEA code. Finally, initial predictive EM loads on DEMO limiter structures are discussed in the case of VDEs following plasma perturbations.
Exogenous and endogenous price jumps belong to different dynamical classes
Authors: Marcaccioli Riccardo , Bouchaud Jean-Philippe , Benzaquen Michael
Published: February 2022

Synchronising a database of stock specific news with 5 years worth of order book data on 300 stocks, we show that abnormal price movements following news releases (exogenous) exhibit markedly different dynamical features from those arising spontaneously (endogenous). On average, large volatility fluctuations induced by exogenous events occur abruptly and are followed by a decaying power-law relaxation, while endogenous price jumps are characterized by progressively accelerating growth of volatility, also followed by a power-law relaxation, but slower than for exogenous jumps. Remarkably, our results are reminiscent of what is observed in different contexts, namely Amazon book sales and YouTube views. Finally, we show that fitting power-laws to individual volatility profiles allows one to classify large events into endogenous and exogenous dynamical classes, without relying on the news feed.
Design and Research of Stepped Wind Turbine Foundation Structure
Authors: Wu Xiaoqing , Jin Junwu , Zhan Fan , Sun Xinjian
Published: February 2022

This paper introduces a design and research of stepped wind turbine foundation and compares it with circular spread foundation and octagonal raft foundation in engineering quantity and constructability. It shows that the stepped wind turbine foundation has clear mechanical behaviour, efficient in design and analysis. It is a good solution in terms of investment and constructability in wind power projects. Finally, a practical application of this stepped foundation design in a wind farm in Pakistan is presented, efficient construction, and good economic benefits are obtained.
Ultrafast Microwave Assisted Synthesis of Three-Dimensional Graphene Material and its Excellent Performance for Supercapacitors
Authors: Wang Wenjian , Shi Xingyu , Xue Weidong , Zhao Rui
Published: February 2022

Ultrafast microwave assisted synthesis of three-dimensional graphene via one-step microwave irradiation method has been reported. The milligram-grade highly conductive acetylene black as the power conversion center, rapidly converts microwave energy into heat and forms local instantaneous high temperature, resulting in partial detachment of functional groups and promoting the recovery of the conductive network of the carbon layers within a few seconds. Interestingly, the nano-scaled acetylene black was found to be tightly bound to the lamella of the 3D graphene, the 3D graphene containing the few acetylene black exhibited a typical double-layer behavior with outstanding specific capacitance of 279.8 F g−1 at 0.5 A g−1 and high capacitance retention over 85% after 20000 cycles. A symmetric supercapacitor assembled in organic electrolyte shown a wide voltage window (0 - 2 V). These satisfactory results provide a potential solution for the manufacture of high-capacity electrochemical energy storage.
Novel and Green Fe3O4@Sio2-L-Cys Magnetic Absorbent for Efficient Removal of Pb (II) from Aqueous Solution
Authors: Su X D , Huang E , Cheng Z , Su Y , Zhong Y H , Deng X
Published: February 2022

In this study, Fe3O4@Sio2-NH2 was synthesized by the modification of Fe3O4 particles with tetraethyl orthosilicate(TEOS) and 3-aminopropyl-Triethoxysilane (APTES), and then the cysteine was grafted with glutaraldehyde as cross-linking agent.The material was characterized by XRD,FIIR and TEM. The effects of temperature, time, initial concentration of Pb(II) and pH value on the adsorption rate of Pb(II) were investigated, and the adsorption mechanism and the regeneration performance of the adsorbent were discussed.The results indicated that when the amount of adsorbent was 0.4g/L, the temperature was 303K, the adsorption time was 2.5h and the pH was 5.02, the adsorption rate of Pb(II) in water can reach up to 98.25%.The adsorption kinetics of Pb(II) on the material accorded with Lagergren quasi-second-order kinetic equation, which belonged to the chemisorption process.Adsorption isothermal curve studies showed that the adsorption of Pb(II) on the material complied with the Langmuir isothermal adsorption model and was a monolayer adsorption.The maximum adsorption capacity of Pb(II) is 120.77mg/g. Adsorption thermodynamics studies showed that the whole system was endothermic reaction,and warming was conducive to the adsorption,which happens spontaneously.After 4 times of the adsorption recycling,the adsorption rate can still reach 92.7%.
Calculation Model for the Selection of Physical Dimensions of a New Type of Heating Curing Building
Authors: Yu N , Shen Z , Wu J S , Kong X R
Published: February 2022

The spatial pattern of the new type of heating curing building directly affects the energy consumption of the PC component and the passive utilisation efficiency of solar energy. Based on the thermal design theory and building energy consumption simulation analysis method, this study constructed the heating-curing energy consumption model and determined the evaluation index of building space shape parameters. Based on the energy consumption model and Energy Plus simulation software, the calculation case—the best spatial shape characteristic parameters of the new-type heating and curing building in the Shijiazhuang area was given. Compared with the traditional steam warming curing, the carbon emission per unit building area was reduced by 33.4% each year, and the carbon emission of one ton of PC component was reduced by 0.97t.
Optimal Design of Energy Supply System Based on River Water Source Heat Pump in Load Intensive Area
Authors: Xiao Jing , Qiu Zejing , Jiang Cheng , Hu Wenbo , Xu Jingzhou
Published: February 2022

Aiming at the contradiction between supply and demand of cooling, heating and electric load in load intensive area, an energy supply system suitable for load intensive area is proposed, and the mathematical model of the system is constructed. Secondly, considering the economic, energy consumption and environmental performance of the system, the evaluation index of system is established, and thus, a multi-objective optimization model is constructed. The weight of different optimization indexes is determined by using analytic hierarchy process. Then, four types of buildings, including residential buildings, offices, hotels and shopping malls are employed and hourly cooling, heating and electric load are simulated using DeST software. Finally, the design optimization of the system is carried out.
Thermodynamic Analysis of Space Regenerative Orc (Srorc) System for Automotive Waste Heat Recovery
Authors: Tong D H , Kong X H , Li M , Liu X , Huang G L , Wang X P
Published: February 2022

In this paper, the space regenerative ORC (SRORC) system is proposed. In SRORC system, the superheated working fluid is divided into two parts after it works completely in the expander. The performance of SRORC system is studied, the performance of ORC system and SRORC system under different conditions are compared and analyzed. From the perspective of latent and sensible heat, the mechanism of using space regeneration to improve the performance of SRORC system is explored. The models of ORC system and SRORC system are built by Aspen plus software. R245fa is chosen as the working fluid because of its excellent performance. The simulation results show that compared with the evaporation temperature, the evaporation pressure has greater influence on the performance of SRORC system under B75 condition. Under C25, B50, A75, B75, and B100 conditions, compared with ORC system, the net output power of SRORC system is increased by 30.7%, 30.3%, 34.4%, 33.2% and 34%, the thermal efficiency is increased by 4.3%, 4.36%, 4.97%, 4.79% and 4.89%, the exergy efficiency is increased by 11.13%, 10.28%, 10.36%, 10.69% and 10.02%, the recovery efficiency of engine power is increased by 3.92%, 2.55%, 2.9%, 2.91% and 3.36%, respectively. The heat recovery rate of IHE-ORC system and SRORC system are 13.7kW and 24.8kW under B75 condition. In SRORC system, liquid working fluid can recover sensible and latent heat of superheated working fluid, and the latent heat accounts for most of the heat recovered.