bluuebunny/crossref_metadata_2025 huggingface dataset:
Ökopsychosomatik und Ökoimmunologie: Was Biodiversität mit Gesundheit zu tun hat
Authors: Arvay Clemens G.
Published: August 2022

Die Ökopsychosomatik beschreibt die Wirkung vonstofflichen sowie nichtstofflichen Stimulanzien aus Ökosystemenauf die psychische und somatische Gesundheitdes Menschen. Sie erforscht die pathogenen und salutogenenUmwelt- und Natureinflüsse, um die daraus gewonnenenErkenntnisse für die öffentliche Gesundheitsowie für die Therapie von Krankheitszuständen nutzbarzu machen. Im ökopsychosomatischen Paradigma wirdder menschliche Organismus als eingebunden in einenevolutionsbedingten Funktionskreis mit seinen natürlichenLebensräumen betrachtet. Der Mensch ist Teil derBiodiversität. Nicht nur Umweltschadstoffe wirken sichungünstig auf Gesundheit und Genesungsaussichtenaus, sondern auch die Durchbrechung des Funktionskreisesdurch Trennung von den Einflüssen intakter Ökosysteme.Die „Waldmedizin“ ist als evidenzbasiertes Beispielder angewandten Ökopsychosomatik zu betrachten.Der Artikel gibt einen Überblick über dasinterdisziplinäre Feld der Ökopsychosomatik.
New Efficient Synthesis of 6,12-Dihydro-5H-quinazolino[3,2-a] quinazolin-5-ones via Ugi/Staudinger/Aza-Wittig/Addition/Nucleophilic Acyl Substitution Sequence
Authors: Ding Ming-Wu , Yang Mao-Lin , Chen Hao-Ran , Zhao Long
Published: August 2022

A new efficient synthesis of 6,12-dihydro-5H-quinazolino[3,2-a]quinazolin-5-ones by sequential Ugi/Staudinger/aza-Wittig/addition/nucleophilic acyl substitution has been developed. α-Amino amides, obtained from Ugi-3CR of 2-azidobenzaldehydes, methyl 2-aminobenzoates, and isocyanides in the presence of catalytic amount of phenylphosphinic acid, reacted with triphenylphosphine and isocyanates to give 6,12-dihydro-5H-quinazolino[3,2-a]quinazolin-5-ones in good yields. This method provides a domino and effective strategy for the preparation of various substituted quinazolino[3,2-a]quinazolin-5-ones under mild reaction condition.
1,4-Naphthoquinone Derivative as Efficient Photolabile Molecule: Concise Synthesis and Photorelease of Various Functional Compounds
Authors: Kawai Tsuyoshi , Morimoto Tsumoru , Liu HaiYing , Suzuki Mikiya , Kakiuchi Kiyomi
Published: August 2022

We report on a series of 1,4-naphthoquinone (NQ)-based photolabile molecules, including various functional compounds to be released under light irradiation. They were efficiently prepared from a common precursor for a photoremovable masking group, by attaching different functional compounds such as alcohols, amines, and acids by a concise synthetic method. Synthesis of the common precursor was optimized for two-step reactions and also for a one-pot reaction involving a 1,4-addition and successive aldol reaction from NQ. The functional compounds, such as alcohols, amines and carboxylic, phosphoric, and sulfonic acids, were masked with the NQ-based precursor and were successfully released by irradiation with UV light (λ = 360 nm) in high yields (>90%).
Generic Health-Related Quality-of-Life Changes after Rhinoplasty: A Prospective Study with Long-Term Results
Authors: Xavier Rui , Azeredo-Lopes Sofia , Menger Dirk-Jan , de Carvalho Henrique Cyrne , Spratley Jorge
Published: August 2022

Objectives Our objective was to investigate changes in specific generic health-related quality-of-life (HRQoL) domains achieved by rhinoplasty, to investigate whether modifications of somatic-, psychologic-, and social-related HRQoL domains are different in patients with functional or aesthetic motivation for rhinoplasty, and to investigate if HRQoL changes are related to a functional or an aesthetic nasal improvement.

Study Design This was a prospective study with 1 year of follow-up.

Methods Fifty-four consecutive Caucasian patients submitted to rhinoplasty were evaluated with 36-item Short Form Health Survey (SF-36) and EuroQuality-of-Life 5 Domain (EQ-5D) questionnaires. To correlate changes in generic HRQoL with functional and aesthetic modifications achieved by rhinoplasty, evaluation of patients also included assessment of Peak Nasal Inspiratory Flow and Nasal Obstruction Symptom Evaluation, Visual Analogue Scale for nasal airway obstruction (NAO), and Rhinoplasty Outcome Evaluation scores.

Modifications in each generic HRQoL health-domain were analyzed to investigate the possible relation with motivation for surgery and with functional or aesthetic improvement.

Results There was a significant improvement in EQ-5D (p < 0.001), EQ-5D VAS (p = 0.002) and in the SF-36 domains of general health (p < 0.001), energy (p < 0.001), physical functioning (p < 0.001), physical limitation (p = 0.005), pain (p = 0.003), and well-being (p = 0.018). Improvement was significant in groups of patients with NAO or in whom a septoplasty was performed and was associated with patient-reported functional improvement. There was a significant improvement in health change (p < 0.001), verified in all groups of patients.

Conclusions This prospective study with long-term results demonstrates that rhinoplasty significantly improves most domains of generic HRQoL. This improvement is associated with patient-reported functional improvement. Emotional limitation and social functioning are not significantly changed by rhinoplasty.

Level of Evidence: IV.
A Novel Craniocervical Junction Compression Severity Index-Based Grading System for Multidirectional Quantification of the Biomechanics at Foramen Magnum of Chiari Malformation Type I
Authors: He Yunsen , Liu Ping , Zhang Mengjun , Guo Lili , Zheng Tao , Yao Yuanpeng , Zheng Qiang , Bao Mingbin , Jiang Chuan , Wu Bo , Liu Jinping
Published: August 2022

Objective This study aimed to establish a novel grading system, based on the craniovertebral junction compression severity index (CVJCSI) for multidirectional quantification at the foramen magnum plane for Chiari malformation type I (CMI).

Methods The CVJCSI grading system was established to stratify patients based on the ventral (modified clivoaxial angle < 138°), dorsal (tonsil herniation), and central (brainstem herniation) CVJ (craniovertebral junction) compression, the CVJCSI grading system was established to stratify patients. The optimal surgical method for each grade was recommended by intragroup comparisons regarding the efficacy of the three operations. Finally, according to the CVJCSI grading system, a prospective validation trial was performed and surgically treated for internal validation.

Results Based on the retrospective study (n = 310), the CVJCSI included six grades: I: syrinx alone without compression; II: dorsal compression; III: dorsal and central compression; IV: ventral compression; V: dorsal and ventral compression; and VI: ventral, dorsal, and central compression. Among all available variables, only the CVJCSI and surgical methods significantly affected the CCOS. The CCOS scores, overall and for each CVJCSI grade, increased in the prospective cohort (n = 42) compared with that in the retrospective analysis.

Conclusions The CVJCSI can be used to stratify CMI patients. The higher the CVJCSI grade, the more severe the CVJ compression and the worse posterior fossa deformity. Meanwhile, the CVJCSI was negatively correlated with the CCOS. The lower the CVJCSI grade, the better the response to surgery, and the less-invasive surgical procedures were warranted. Finally, the prospective cohort study validated the proposed CVJCSI-based surgical protocols.
Synthesis of Dehydromuscone by an Alkene Metathesis Macrocyclization Reaction at 0.2 M Concentration
Authors: Leyva-Pérez Antonio , Garnes-Portolés Francisco , Sánchez-Quesada Jorge , Espinós-Ferri Estela
Published: August 2022

The industrial fragrance compound dehydromuscone was synthesized in five linear steps and 19% overall yield. The synthesis features a highly efficient nondiluted ring-closing metathesis macrocyclization reaction as a key step that proceeds at a 0.2 M concentration in the presence of 0.1 mol% Nitro-Grela catalyst. The synthesis employs commercially available linear starting materials and is shorter by at least two steps than the current industrial synthesis route.
Rapid Detection of Apixaban by a ROTEM-Based Approach and Reversibility with Andexanet Alfa or DOAC-Stop
Authors: Taune Viktor , Skeppholm Mika , Ågren Anna , Wikman Agneta , Hillarp Andreas , Wallén Håkan
Published: August 2022

Background A rapid test to detect apixaban treatment would be useful in acute situations such as major bleeding, urgent surgery, or in acute thrombosis.

Objective This article aims to study if the viscoelastic test rotational thromboelastometry (ROTEM) can rapidly detect apixaban in whole blood using modified triggers based on factor Xa (FXa) or Russell viper venom (RVV).

Method ROTEM clotting time (CT) was measured in samples from 40 patients on apixaban treatment, and in vitro in samples spiked with apixaban (20–500 ng/mL). Commercially available trigger Ex-tem was compared with modified triggers based on FXa or RVV. Reversibility of apixaban in the samples was studied; CT was measured with and without addition of DOAC-Stop or andexanet alfa, respectively, and the difference in CT was calculated (CTdiff).

Results Using FXa as trigger, we detected apixaban concentrations at 20 ng/mL and above with 100% sensitivity and 100% specificity in patient samples and in vitro. Corresponding data for Ex-tem were 92% sensitivity and 100% specificity in patients, and 94% sensitivity and 100% specificity in vitro, and for RVV 97% sensitivity and 94% specificity in patients, and 97% sensitivity and 100% specificity in vitro, respectively. CTdiff data were similar. Patient sample data were obtained within 20 minutes from sampling.

Conclusion Apixaban at low therapeutic concentrations was detected within 20 minutes, and with high sensitivity and specificity. A trigger based on FXa outperformed the commercial trigger Ex-tem and a trigger based on RVV. ROTEM with a FXa-based trigger is a promising method to detect apixaban bedside in acute settings.
Misoprostol Administration Before Hysteroscopy Procedures – A Retrospective Analysis
Authors: Inácio Quênya Antunes Silveira , Troncon Júlia Kefalás , Valério Fernando Passador , Herren Helmer , Nogueira Antônio Alberto , Neto Omero Benedicto Poli , Silva Júlio César Rosa e
Published: August 2022

Objective To evaluate the use of misoprostol prior to hysteroscopy procedures regarding technical ease, the presence of side effects, and the occurrence of complications.

Methods This is a retrospective, observational, analytical, case-control study, with the review of medical records of 266 patients followed-up at the Gynecological Videoendoscopy Sector of the Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto of the Universidade de São Paulo (HCFMRP – USP, in the Portuguese acronym) from 2014 to 2019, comparing 133 patients who used the drug before the procedure with 133 patients who did not.

Results The occurrence of postmenopausal uterine bleeding was the main indication for hysteroscopy and revealed a statistical difference between groups (p < 0.001), being present in 93.23% of the patients in the study group and in 69.7% of the patients in the control group. Only 2 patients (1.5%) in the study group reported adverse effects. Although no statistical differences were observed regarding the occurrence of complications during the procedure (p = 0.0662), a higher total number of complications was noted in the group that used misoprostol (n = 7; 5.26%) compared with the group that did not use the drug (n = 1; 0.75%), a fact that is clinically relevant. When evaluating the ease of the technique (measured by the complete performance of all steps of the hysteroscopy procedure), it was verified that although there was no difference between groups (p = 0.0586), the control group had more than twice as many incompletely performed procedures (n = 17) when compared with the group that used misoprostol previously (n = 8), which is also clinically relevant.

Conclusion The use of misoprostol prior to hysteroscopy in our service indicated that the drug can facilitate the performance of the procedure, but not without side effects and presenting higher complication rates.
Long-Term Outcomes of Laminectomy in Lumbar Spinal Stenosis: A Systematic Review and Meta-Analysis
Authors: Sajadi Kiavash , Azarhomayoun Amir , Jazayeri Seyed Behnam , Baigi Vali , Ranjbar Hameghavandi Mohammad Hosein , Rostamkhani Sabra , Atlasi Rasha , Faghih Jooybari Morteza , Ghodsi Zahra , Vaccaro Alexander R. , Khorasanizadeh MirHojjat , Rahimi-Movaghar Vafa
Published: August 2022

Objective Lumbar spinal stenosis (LSS) patients suffer from significant pain and disability. To assess long-term safety and efficacy of laminectomy in LSS patients, a systematic review and meta-analysis study was conducted.

Methods Literature review in MEDLINE, Embase, Scopus, Web of Science, and Cochrane Library databases was performed using a predefined search strategy. Articles were included if they met the following characteristics: human studies, LSS, and at least 5 years of follow-up. Outcome measures included patient satisfaction, pain, disability, claudication, reoperation rates, and complications.

Results Twelve articles met the eligibility criteria for our study. Overall, there was low-quality evidence that patients undergoing laminectomy, with at least 5 years of follow-up, have significantly more satisfaction, and less pain and disability, compared with the preoperative baseline. Assessment of neurogenic intermittent claudication showed significant improvement in walking abilities. We also reviewed the postoperative complication and adverse events in the included studies. After meta-analysis was performed, the reoperation rate was found to be 14% (95% confidence interval: 13–16%).

Conclusion Our study provides low-quality evidence suggesting that patients undergoing laminectomy for LSS have less disability and pain and can be more physically active postoperatively.
The expected impact of cultivated and plant-based meats on jobs: the views of experts from Brazil, the United States and Europe
Authors: Morais-da-Silva Rodrigo Luiz , Villar Eduardo Guedes , Reis Germano Glufke , Sanctorum Hermes , Molento Carla Forte Maiolino
Published: August 2022

Cultivated and plant-based meats are substitutes for conventional animal meat products. As radical innovations, they may trigger profound social and economic changes. Despite the many benefits of alternative meats, such as environmental sustainability, animal welfare, human health and food safety, some unintended consequences remain unexplored in the literature. In this paper, we studied the potential impact of the meat production system transition on jobs. Using a survey, we compared opinions regarding the impact on jobs in Brazil, the United States and Europe, according to alternative protein experts. Our results showed the potential of plant-based and cultivated meat production to create new and higher-skilled jobs. The data analysis also suggested that the impact of novel food production systems on jobs in conventional meat production may be different for each stage of the value chain. In particular, the results showed a pressure point on animal farmers, who may be most affected in a fast transition scenario. Considering the studied geographical contexts, Brazilian professionals were more optimistic about the potential of plant-based and cultivated meat production to create new jobs. Our findings may provide new insights for the development of policies, measures and strategies that promote job creation, skills and income in view of the ongoing transition.
Preparing building cooling systems for a carbon-free future
Authors: Lim Alane
Published: August 2022

Improved heat-driven refrigeration systems show significant improvements over traditional versions.
Bubbles generate their own kind of turbulence
Authors: Piccone Ashley
Published: August 2022

Simulations of bubble-induced turbulence, while fundamentally different from those of classical homogeneous isotropic turbulence, do not need to account for bubble shape, topology, or breakup and coalescence.
Cryogenic chamber design improved with 3D printing
Authors: Thompson Avery
Published: August 2022

Consumer-grade, 3D-printed plastic functions extremely well at cryogenic temperatures and can be used to advance existing designs.
Multiferroic antiferromagnetic artificial synapse
Authors: Nance John , Roxy Kawsher A. , Bhanja Sanjukta , Carman Greg P.
Published: August 2022

Artificial intelligence frameworks utilizing unsupervised learning techniques can avoid the bottleneck of labeled training data required in supervised machine learning systems, but the programming time of these systems is inherently limited by their hardware implementations. Here, a finite-element model coupling micromagnetics and dynamic strain is used to investigate a multiferroic antiferromagnet as a high-speed artificial synapse in artificial intelligence applications. The stability of strain-induced intermediate antiferromagnetic magnetization states (non-uniform magnetization states between a uniform 0 or 1), along with the minimum time scale at which these states can be programmed is investigated. Results show that due to the antiferromagnetic material's magnetocrystalline anisotropy, two intermediate states (Néel vector 1/3z, 2/3x, and Néel vector 2/3z, 1/3x) between fully x and fully z Néel vector orientations can be successfully programmed using 375 με strain pulses, and that the time associated with this programming is limited to ∼0.3 ns by the material's antiferromagnetic resonance frequency.
A 3D printed photoreactor for investigating variable reaction geometry, wavelength, and fluid flow
Authors: Riddell Alexander , Kvist Patric , Bernin Diana
Published: August 2022

Research in the field of photochemistry, including photocatalysis and photoelectrocatalysis, has been revitalized due to the potential that photochemical reactions show in the sustainable production of chemicals. Therefore, there is a need for flexible photoreactor equipment that allows for the evaluation of the geometry, light wavelength, and intensity of the vessel, along with the fluid flow in various photochemical reactions. Light emitting diodes (LEDs) have narrow emission spectra and can be either pulsed or run continuously; being flexible, they can be arranged to fit the dimensions of various types of the reactor vessel, depending on the application. This study presents a 3D printed photoreactor with the ability to adjust distances easily and switch between high-power LED light sources. The reactor design utilizes customized printed circuit boards to mount varying numbers and types of LEDs, which enables multiple wavelengths to be used simultaneously. These LED modules, comprised of heat sinks and cooling fans, fulfill the higher heat dissipation requirements of high-power LEDs. The flexibility of the reactor design is useful for optimizing the reaction geometry, flow conditions, wavelength, and intensity of photochemical reactions on a small scale. The estimates for incident light intensity under five possible reactor configurations using ferrioxalate actinometry are reported so that comparisons with other photoreactors can be made. The performance of the photoreactor for differing vessel sizes and distances, in both the flow and batch modes, is given for a photochemical reaction on 2-benzyloxyphenol—a model substance for lignin and applicable in the production of biobased chemicals.
Effect of insulator length and fill pressure on filamentation and neutron production in a 4.6 kJ dense plasma focus
Authors: Hahn E. N. , Ghosh S. , Eudave V. , Narkis J. , Angus J. R. , Link A. J. , Conti F. , Beg F. N.
Published: August 2022

Optimization of neutron yields from dense plasma focus devices is a complex multi-faceted challenge that necessitates the prudent selection of mechanical constraints such as the electrode and insulator geometries. Here, the neutron yield is found to significantly depend on the insulator length. As the length of the insulator increases, the exposed anode length traveled by the sheath during the run-down phase decreases. This suggests an increase in the optimal fill pressure with increasing insulator length to maintain the pinch time near peak current. However, in the present study, the opposite trend is observed—the optimal fill pressure for neutron production decreases with increasing insulator length. Optical probing of the sheath from run-down to the pinch reveals significant plasma filamentation with increasing pressure and a dependence of insulator length on filamentation onset. A direct consequence of increased filamentation is a reduction in mass sweeping efficiency, directly quantified as a function of fill pressure for the first time.
Femtosecond diffraction and dynamic high pressure science
Authors: Wark Justin S. , McMahon Malcolm I. , Eggert Jon H.
Published: August 2022

Solid-state material at high pressure is prevalent throughout the Universe, and an understanding of the structure of matter under such extreme conditions, gleaned from x-ray diffraction, has been pursued for the best part of a century. The highest pressures that can be reached to date (2 TPa) in combination with x-ray diffraction diagnosis have been achieved by dynamic compression via laser ablation [A. Lazicki et al., Nature 589, 532–535 (2021)]. The past decade has witnessed remarkable advances in x-ray technologies, with novel x-ray Free-Electron-Lasers (FELs) affording the capacity to produce high quality single-shot diffraction data on timescales below 100 fs. We provide a brief history of the field of dynamic compression, spanning from when the x-ray sources were almost always laser-plasma based, to the current state-of-the art diffraction capabilities provided by FELs. We give an overview of the physics of dynamic compression, diagnostic techniques, and the importance of understanding how the rate of compression influences the final temperatures reached. We provide illustrative examples of experiments performed on FEL facilities that are starting to give insight into how materials deform at ultrahigh strain rates, their phase diagrams, and the types of states that can be reached. We emphasize that there often appear to be differences in the crystalline phases observed between the use of static and dynamic compression techniques. We give our perspective on both the current state of this rapidly evolving field and some glimpses of how we see it developing in the near-to-medium term.
Global-in-time semiclassical regularity for the Hartree–Fock equation
Authors: Chong J. J. , Lafleche L. , Saffirio C.
Published: August 2022

For arbitrarily large times T > 0, we prove the uniform-in-ℏ propagation of semiclassical regularity for the solutions to the Hartree–Fock equation with singular interactions of the form V(x)=±x−a with a∈(0,12). As a by-product of this result, we extend to arbitrarily long times the derivation of the Hartree–Fock and the Vlasov equations from the many-body dynamics provided in the work of Chong et al. [arXiv:2103.10946 (2021)].
On the wake response of a square cylinder subjected to an inline nonharmonic forcing
Authors: Krishnan Hrisheekesh , Agrawal Amit , Sharma Atul
Published: August 2022

In this work, we study the effect of two spectrally simple nonharmonic inline forcing waveforms on the wake response of a square cylinder. The characteristics of wake response under nonharmonic forcing were studied and compared to wake response under harmonic forcing for a constant Reynolds number 100. By varying the relative strength of the spectral components and the secondary frequency of the nonharmonic forcing of the inflow, an asymmetric modulated wake and an asymmetric 2P + 2S wake were observed for a two-tone nonharmonic forcing. These modes combine the features of the wake response of individual spectral components. In some regions of the parameter space, the wake response did not correlate well with the spectral components of harmonic forcing. An amplitude-modulated forcing was also studied. For amplitude-modulated forcing, the additional frequency component did not affect the wake structure. This observation indicates that the wake may act as a low pass filter for inline flow frequency components above the natural vortex shedding frequency.
Schottky-to-Ohmic switching in ferroelectric memristors based on semiconducting Hf0.93Y0.07O2 thin films
Authors: Müller Moritz L. , Becker Maximilian T. , Strkalj Nives , MacManus-Driscoll Judith L.
Published: August 2022

We demonstrate resistive switching and memristive behavior in devices consisting of ultrathin (4.5 nm) semiconducting, epitaxial ferroelectric Hf0.93Y0.07O2 (YHO) films on La0.7Sr0.3MnO3-buffered, Nb-doped SrTiO3 single crystal substrates with Au top electrodes. Unlike the tunneling-driven current–voltage characteristics of ferroelectric tunnel junctions which utilize ultrathin insulating (fully depleted) ferroelectric films, the semiconducting nature of our YHO films, i.e., the presence of free charge carriers introduced by Y doping, results in radically different current–voltage characteristics. Current–voltage measurements indicate a polarization-modulated transition from Schottky-barrier-controlled charge transport to Ohmic conduction in the YHO devices, which results in a large on/off ratio of up to 540. Moreover, voltage pulse train measurements reveal a broad range of accessible resistance states, which indicates the memristive behavior of the devices. Our results represent an important step toward the development of future nonvolatile memory and brain-inspired neuromorphic computing applications based on ultrathin semiconducting ferroelectric films.
Coupled matter-wave solitons on oscillating reflectors under the effects of gravity
Authors: Dey Kajal Krishna , Sekh Golam Ali
Published: August 2022

We consider coupled matter-waves solitons in Bose–Einstein condensates and study the dynamics under the combined effects of gravity and reflecting potential. The dynamics of matter-wave near a reflector oscillating periodically with time generates the dynamics of a special kind of localized structure called oscillon. We derive a mechanical model for the coupled oscillon dynamics. We pay special attention to the inter-component interaction and see that effective potential depends on the type (repulsive/attractive) and strength of interaction. We find that the inter-component interaction affects the frequency of oscillation and introduces an initial phase-shift between the reflector and the oscillon. This phase-shift, in addition to instantaneous phase change due to the oscillation of the reflector, results in interesting dynamics. The coupled oscillon is found to execute quasi-periodic and chaotic dynamics for both attractive and repulsive inter-component interactions. We analyze the maximum value of Lyapunov exponents and show that the dynamical response of the coupled oscillon depends on the ratio of the center of mass position and their separation.
Experimental research on spontaneous combustion of coal oxidized by ultraviolet photocatalysis
Authors: Zhang Xun , Zeng Bin , Lu Bing , Wang Gang , Gao Fei
Published: August 2022

To study the effect of ultraviolet light on the spontaneous combustion characteristics of coal, Lijiahao long-flame coal was selected for irradiation treatment with a self-made ultraviolet light irradiation device. After irradiation for 0, 1, 2, 4, and 8 h, thermogravimetric experiments and Fourier transform infrared spectroscopy experiments were carried out. Compared with the raw coal, the dry cracking temperature, the ignition point temperature, and the maximum weight loss rate temperature of coal samples irradiated for 2 h by ultraviolet light were advanced to different degrees. The ignition activation energy was 0.62, 0.56, 0.59, and 0.91 times that of the raw coal after 1, 2, 4, and 8 h of ultraviolet light irradiation. The ultraviolet light irradiation accelerated the oxidation of –CH3, –CH2−, and –OH, resulting in enhanced coal activity. It shows that ultraviolet light irradiation has a promoting effect on the spontaneous combustion of coal, and the best promotion effect is observed when ultraviolet light is irradiated for 2 h. After 2 h of ultraviolet light irradiation, compared with the raw coal, the content of ether group in the coal structure decreased by 6.79%, the content of methyl and methylene in the benzene ring decreased by 8.68%, the content of C=O and carboxylic acid increased by 30.21%, the content of hydroxy ether and hydroxyl π hydrogen bond decreased by 14.94%, and the content of self-associating hydroxyl hydrogen bonds increased by 16.59%. It shows that ultraviolet light can destroy aromatic hydrocarbons in coal, catalyze the hydrolysis reaction of esters and ethers in coal to generate –OH and –COOH, and promote the oxidative spontaneous combustion of coal.
Control of low-frequency guided elastic wave modes in a hollow pipe using a meta-surface
Authors: Pillarisetti Lalith Sai Srinivas , Lissenden Cliff J. , Shokouhi Parisa
Published: August 2022

A locally resonant meta-surface for preferential excitation of a guided mode in a hollow pipe can improve ultrasonic guided wave inspection of pipelines. The proposed meta-surface comprises a periodic arrangement of bonded prismatic rod-like resonators in the circumferential and axial directions of the pipe. We demonstrate the presence of bandgaps for the low-frequency axisymmetric longitudinal modes L(0,1) and L(0,2) and the torsional mode T(0,1). The generated bandgaps can be used to filter the higher harmonics associated with the system nonlinearity to improve nonlinear ultrasonic measurements on pipes. These bandgaps exist even for the non-axisymmetric flexural modes but with their hybridized dispersion curves exhibiting mode-coupling for higher circumferential orders. Moreover, a “partial” bandgap is obtained where preferential transmission of the L(0,2) mode over L(0,1) is possible. We discuss the potential advantages of this partial bandgap to improve pipeline inspections using the L(0,2) mode. Time-domain finite element analyses are used to validate the presence of these bandgaps under radial, circumferential, and axial excitation that mimics the excitation using a ring of piezoelectric transducers. Finally, we discuss the influence of resonator spacing, filling fraction, and the number of resonator rings on the bandgaps for an informed meta-surface design.
A brief review of reconstructions and electronic structures of MoS2 zigzag edges
Authors: Bao Kejie , Zhu Junyi
Published: August 2022

Transition metal dichalcogenides, mainly focusing on MoS2, have attracted intensive studies in terms of their electronic and optical properties. Their lower-dimensional counterparts, such as nanoribbons and nanoclusters, gradually draw more research attention because of their potential applications in various electronic and spintronic devices. The edge states are essential to determine the intriguing electronic and magnetic properties of the nanocrystals. In this review, we mainly focus on the zigzag edges in the MoS2 system because they are more common in experiments. We first review the physical properties of the unreconstructed edges and then introduce the principles of edge reconstructions, the electron counting model (ECM). Then, based on the ECM, intrinsic edge reconstructions with different periodicities are discussed. The literature we reviewed suggests that the conductivities and magnetism of the edge states are highly related to the periodicities of the edges. Finally, the effects of the edge passivation with extrinsic atoms are reviewed. Edge passivation plays an important role in tuning the electronic and magnetic properties of the edge states and determining the morphology during the crystal growth. Furthermore, MoS2 zigzag edges could be an ideal platform to investigate the interplay between the edge states with different periodicities and magnetic dopants in the future.
Theoretical and experimental study of the overdense plasma generation in a miniaturized microwave ion source
Authors: Wu Wenbin , Peng Shixiang , Zhang Ailin , Ma Tenghao , Jiang Yaoxiang , Li Kai , Cui Bujian , Guo Zhiyu , Chen Jiaer
Published: August 2022

To understand the plasma evolution mechanism of microwave ion source (MIS), a hybrid discharge heating (HDH) mode is proposed. That mode contains two parts: ignition discharge by surface wave plasma (SWP) and ionization by electron cyclotron resonance. Compared with the traditional electron cyclotron heating (ECH) mode, the HDH mode has a wider scope of application for MIS with a chamber diameter smaller than the cutoff size. The spatio-temporal evolution of electric field, power deposition, electron temperature, and electron density of a miniaturized microwave ion source (MMIS) at Peking University is investigated based on the HDH mode. In addition, the MMIS is optimized based on the theoretical results of the HDH mechanism. Preliminary experiments show that a mixed hydrogen continuous wave beam of up to 25 mA at 30 keV can be extracted with a power efficiency of 25 mA/100 W.
Investigation of thrust vector angle control law based on micro-turbojet engine
Authors: Chi Shaoqing , Gu Yunsong , Gong Dongsheng , Li Linkai
Published: August 2022

The fluid thrust vectoring nozzle has a fixed profile, few moving parts, and lightweight structure, providing effective flight control for high maneuvering aircraft. The nonlinear control law of the jet deflection angle is one of the critical problems of fluid thrust vector technology. However, the research on the deflection control law of the thermal jet in a fluid thrust vectoring nozzle is not ideal. In this paper, the control law of micro-turbojet engines under a thermal jet is studied by numerical simulations and experiments. The numerical results show that the nonlinear control law of the jet deflection angle is caused by the vortex structure between the main jet and the nozzle wall. The numerical results show that the passive flow control method can effectively change the vortex structure distribution on the nozzle wall by changing the shape of the nozzle outlet structure. This change of flow structure can effectively make the jet deflection control law close to linear. The experimental results show that the nozzle with this configuration can continuously and controllably deflect the main jet under the thermal jet of the micro-turbojet engine. The vector deflection control law of this nozzle configuration is close to linear and has less thrust loss.
Correction of residual errors in configuration interaction electronic structure calculations
Authors: Whitten Jerry L.
Published: August 2022

Methods for correcting residual energy errors of configuration interaction (CI) calculations of molecules and other electronic systems are discussed based on the assumption that the energy defect can be mapped onto atomic regions. The methods do not consider the detailed nature of excitations but instead define a defect energy per electron that is unique to a specific atom. Defect energy contributions are determined from calculations on diatomic and hydride molecules and then applied to other systems. Calculated energies are compared with experimental thermodynamic and spectroscopic data for a set of 41 mainly organic molecules representing a wide range of bonding environments. The most stringent test is based on a severely truncated virtual space in which higher spherical harmonic basis functions are removed. The errors of the initial CI calculations are large, but in each case, including defect corrections brings calculated CI energies into agreement with experimental values. The method is also applied to a NIST compilation of coupled cluster calculations that employ a larger basis set and no truncation of the virtual space. The corrections show excellent consistency with total energies in very good agreement with experimental values. An extension of the method is applied to dmsn states of Sc, Ti, V, Mn, Cr, Fe, Co, Ni, and Cu, significantly improving the agreement of calculated transition energies with spectroscopic values.
Spectral overlapping single-cavity dual-comb fiber laser with well-controlled repetition rate difference
Authors: Hu G. Q. , Zhu L. Q. , Sun G. K. , Lu L. L. , You R. , Liu Y. , He W. , Dong M. L.
Published: August 2022

We investigate free-running dual-comb pulses with overlapping spectra and well-controlled repetition rate difference in a single birefringent fiber cavity. Multiple linear and nonlinear soliton formation mechanisms in an all-fiber laser with partial polarization maintaining fiber are experimentally observed and validated for switchable and tunable dual-comb pulse emissions. Linear polarization mode dispersion is first exploited to emit polarization-multiplexed pulses with the upper limit of repetition rate difference at kHz level. By further tailoring linear birefringence, birefringence filter effect and nonlinear polarization evolution are well leveraged to emit hybrid mode-locked pulses with the lower limit at 10-Hz level. The lower limit of ∼12 Hz and nearly two order-of-magnitude tunable range of repetition rate difference are highlighted. Moreover, overlapping spectra and the passive mutual coherence between pulses in the free-running state are clarified, indicating the potential of the simplification of amplification system and single-cavity dual-comb source.
Alternating one-phase and two-phase crystallization mechanisms in octahedral patchy colloids
Authors: Garaizar Adiran , Higginbotham Tim , Sanchez-Burgos Ignacio , Tejedor Andres R. , Sanz Eduardo , Espinosa Jorge R.
Published: August 2022

Colloidal systems possess unique features to investigate the governing principles behind liquid-to-solid transitions. The phase diagram and crystallization landscape of colloidal particles can be finely tuned by the range, number, and angular distribution of attractive interactions between the constituent particles. In this work, we present a computational study of colloidal patchy particles with high-symmetry bonding—six patches displaying octahedral symmetry—that can crystallize into distinct competing ordered phases: a cubic simple (CS) lattice, a body-centered cubic phase, and two face-centered cubic solids (orientationally ordered and disordered). We investigate the underlying mechanisms by which these competing crystals emerge from a disordered fluid at different pressures. Strikingly, we identify instances where the structure of the crystalline embryo corresponds to the stable solid, while in others, it corresponds to a metastable crystal whose nucleation is enabled by its lower interfacial free energy with the liquid. Moreover, we find the exceptional phenomenon that, due to a subtle balance between volumetric enthalpy and interfacial free energy, the CS phase nucleates via crystalline cubic nuclei rather than through spherical clusters, as the majority of crystal solids in nature. Finally, by examining growth beyond the nucleation stage, we uncover a series of alternating one-phase and two-phase crystallization mechanisms depending on whether or not the same phase that nucleates keeps growing. Taken together, we show that an octahedral distribution of attractive sites in colloidal particles results in an extremely rich crystallization landscape where subtle differences in pressure crucially determine the crystallizing polymorph.
Interaction confinement and electronic screening in two-dimensional nanofluidic channels
Authors: Kavokine Nikita , Robin Paul , Bocquet Lydéric
Published: August 2022

The transport of fluids at the nanoscale is fundamental to manifold biological and industrial processes, ranging from neurotransmission to ultrafiltration. Yet, it is only recently that well-controlled channels with cross sections as small as a few molecular diameters became an experimental reality. When aqueous electrolytes are confined within such channels, the Coulomb interactions between the dissolved ions are reinforced due to dielectric contrast at the channel walls: We dub this effect “interaction confinement.” Yet, no systematic way of computing these confined interactions has been proposed beyond the limiting cases of perfectly metallic or perfectly insulating channel walls. Here, we introduce a new formalism, based on the so-called surface response functions, that expresses the effective Coulomb interactions within a two-dimensional channel in terms of the wall’s electronic structure, described to any desired level of precision. We use it to demonstrate that in few-nanometer-wide channels, the ionic interactions can be tuned by the wall material’s screening length. We illustrate this approach by implementing these interactions in Brownian dynamics simulations of a strongly confined electrolyte and show that the resulting ionic conduction can be adjusted between Ohm’s law and a Wien effect behavior. Our results provide a quantitative approach to tuning nanoscale ion transport through the electronic properties of the channel wall material.
Giant sensitivity to magnetic field variation in the spin wave interferometer based on the system of exchange-coupled films of yttrium iron garnet
Authors: Vysotskii S. , Kozhevnikov A. , Balinskiy M. , Khitun A. , Filimonov Y.
Published: August 2022

In this work, we present experimental data on the interference of backward volume magnetostatic wave (BVMSW) counter-propagating in the structure with two exchange-coupled yttrium iron garnet layers. The layers are engineered to have different saturation magnetization that gives a possibility to BVMSW resonantly interacting with exchange modes of the two-layer structure. The BVMSW is excited by two antennas placed on top of the structure, while the third one placed between them is used for the detection of inductive voltage V generated by waves superposition. It is shown that maximal changes of the output inductive signal δV with the variation of magnetic field δH occur if, first, the waves interfere destructively and, second, the frequency corresponds to the resonant interaction of BVMSW with the exchange waves. In this case, obtained data reveal large sensitivity S = δV/δH approaching S ≈ 267 dB/Oe in the vicinity ±0.1 Oe of the resonant field H. The observed high sensitivity is of great importance for the development of compact sensitive magnetometers operating at room temperature.
Multilevel simulation of hard-sphere mixtures
Authors: Rohrbach Paul B. , Kobayashi Hideki , Scheichl Robert , Wilding Nigel B. , Jack Robert L.
Published: August 2022

We present a multilevel Monte Carlo simulation method for analyzing multi-scale physical systems via a hierarchy of coarse-grained representations, to obtain numerically exact results, at the most detailed level. We apply the method to a mixture of size-asymmetric hard spheres, in the grand canonical ensemble. A three-level version of the method is compared with a previously studied two-level version. The extra level interpolates between the full mixture and a coarse-grained description where only the large particles are present—this is achieved by restricting the small particles to regions close to the large ones. The three-level method improves the performance of the estimator, at fixed computational cost. We analyze the asymptotic variance of the estimator and discuss the mechanisms for the improved performance.
Aluminum air bridges for superconducting quantum devices realized using a single-step electron-beam lithography process
Authors: Janzen N. , Kononenko M. , Ren S. , Lupascu A.
Published: August 2022

In superconducting quantum devices, air bridges enable increased circuit complexity and density, and mitigate the risk of microwave loss arising from mode mixing. We implement aluminum air bridges using a simple process based on single-step electron-beam gradient exposure. The resulting bridges have sizes ranging from 20 µm to 100 µm, with a yield exceeding 99% for lengths up to 36 µm. When used to connect ground planes in coplanar waveguide resonators, the induced loss contributed to the system is negligible, corresponding to a loss per bridge less than 1.0×10−8. The bridge process is compatible with Josephson junctions and allows for the simultaneous creation of low loss bandages between superconducting layers.
The Maxwell-scalar field system near spatial infinity
Authors: Minucci Marica , Macedo Rodrigo Panosso , Valiente Kroon Juan A.
Published: August 2022

We make use of Friedrich’s representation of spatial infinity to study asymptotic expansions of the Maxwell-scalar field system near spatial infinity. The main objective of this analysis is to understand the effects of non-linearities of this system on the regularity of solutions and polyhomogeneous expansions at null infinity and, in particular, at the critical sets where null infinity touches spatial infinity. The main outcome from our analysis is that the nonlinear interaction makes both fields more singular at the conformal boundary than what is seen when the fields are non-interacting. In particular, we find a whole new class of logarithmic terms in the asymptotic expansions, which depend on the coupling constant between the Maxwell and scalar fields. We analyze the implications of these results on the peeling (or rather lack thereof) of the fields at null infinity.
Study of rotor–stator interaction phenomenon in a double-suction centrifugal pump with impeller vane trailing edge as a design parameter
Authors: Gangipamula Rajavamsi , Ranjan Pritanshu , Patil Ranjit S
Published: August 2022

Various geometrical parameters, such as cut-water clearance, volute tongue location, tongue radius, vane trailing edge profile, and flow parameters like speed and operating point, affect the rotor–stator interaction in a centrifugal pump. In the present investigation, vane trailing edge is selected as a design parameter for profile modifications to study and reduce the rotor–stator interaction intensity and hence the pressure pulsations. A double-suction centrifugal pump with tangential discharge volute (M1) and specific speed (ns) 19 has been selected for the numerical experiments. Transient analysis using detached eddy simulation is used for predicting flow parameter behavior at impeller periphery (primary source) and volute tongue locations (secondary source). The impeller periphery probes in the rotor–stator interaction zone are used to identify the intensity of the jet-wake flow phenomenon and its interaction with the volute tongue. Similar strategy has been applied by modifying the trailing-edge profile of the original geometry with vane underfiling (M2) and the M2 vane geometry with novel trailing-edge profile (M3). The pressure pulsation behavior along the impeller periphery (primary source) shows the strong reduction of pressure amplitude near volute tongue by 42% in M3 compared to M1 aligning with the reduction of jet-wake flow intensity. The pressure fluctuation (rms) near volute tongue (secondary source) shows an average reduction of 11% in modified trailing edge (M3) relative to M1. The intensified rotor–stator interaction due to vortex shedding in M2 causes relatively higher pressure fluctuations (rms) near volute tongue compared to M1 and M3.