bluuebunny/crossref_metadata_2025 huggingface dataset:
Smart Cities for People with IDD - Foundations for Digitally Inclusive Healthcare Ecosystems
Authors: Badr Nabil Georges
Published: February 2023

Smart cities require smart healthcare. In a smart city, the purpose of citywide efforts has the fundamental objectives of livability, sustainability, and productivity. Some well-intentioned smart city programs unintentionally worsen inequality when they lack transparency, fail to involve the community or ignore the varied requirements and preferences of residents. To address ongoing health disparities among persons with intellectual disabilities, patient-centred preventive healthcare that considers both their physical and mental health needs must be prioritized. Engagement and inclusion must at the forefront of smart city initiatives that shift from being technology-centric to citizen-centric. We bring attention to pillars of interaction in inclusive smart cities in the context of care for people with intellectual and developmental disabilities. We explore the fundamentals of a digitally inclusive healthcare service ecosystem for people with IDD through the lens of the Actor for Actor framework to learn about the foundational facilities for IDD patients’ to engage an establish care pathways.
A semantic-based approach for automating compliance by the design of digital services - a case study in the academic sector
Authors: Di Marzo Serugendo Giovanna , Caselli Ashley , Cappelli Maria Assunta , Friha Lamia , Hugentobler Alain , Cissé Kerfalla , Mulard Paul , Missiri Nikita , Martelli Audrey , Huyhn Bernard , Turhan Ismet Cem , Sadeghi Obaydollah , Bauch Saleh , Buzgheiba Ahmed
Published: February 2023

Monitoring University students’ progress, in an interactive, synchronised, and coordinated way across a given study program is a challenge. Indeed, for a given student journey, University actors need a service offering personalised views and actions depending on their role (students, study advisors, scientific committee, faculty members, admission office), all linked to the same underlying information system, and abiding study regulations. The challenge is even greater when it comes to scaling up and providing such service for the whole University community (approx. 23K members in Geneva). Following a service science approach, we derived a method for automatically generating a service, compliant by design to study regulations, and offering personalised views to the various actors. The automatic implementation of the study regulations is based on the definition of generic rules able to define the different elements of the regulations that need to be respected across all curricula and programs. We provide a case study based on the PhD students regulations. We describe a proof-of-concept instantiating the service from the rules, role-centric views of the interface, as well as the underlying architecture relying on a semantic reasoning engine. The work presented in this paper has the potential to alleviate and improve the tasks of all the various actors involved in students monitoring, going beyond PhD students. This approach automatises the implementations of any study program and can be applied to any University.
Psychometrische Überprüfung eines Ein-Item-Screeners
für Schlafbeschwerden
Authors: Klimt Franziska , Brähler Elmar , Stöbel-Richter Yve , Zenger Markus , Berth Hendrik
Published: February 2023

Ziel Schlafbeschwerden zählen zu den häufigsten
gesundheitlichen Beschwerden in der Allgemeinbevölkerung. Der Bedarf
nach guten Screeninginstrumenten und Präventionsangeboten ist
groß. Ziel der vorliegenden Studie ist es, ein
Ein-Item-Screeninginstrument zu evaluieren und damit einen Beitrag zur
Verbesserung der Früherkennung zu leisten.

Methoden Es werden Daten der Sächsischen
Längsschnittstudie (SLS) analysiert. Auf Basis der 32. Erhebungswelle
(n=321, 172 Frauen, 149 Männer, M Alter=48,42,
SD=0,64) wird das G-Score Item #3 („Hatten Sie in den letzten 12
Monaten folgende Beschwerden? Bitte geben Sie an, wie häufig diese
auftraten. – Schlaflosigkeit“) im Hinblick auf die
psychometrischen Gütekriterien evaluiert. Eine Receiver Operating
Characteristic (ROC)-Analyse wird berechnet, um die prädiktive
Validität des G-Score Item #3 zu beurteilen.

Ergebnisse Die mittlere Retestreliabilität des G-Score Item #3
beträgt .70 (p<0,001). Die Korrelation mit der Jenkins Sleep
Scale (JSS) betrug r=0,79 (p<0,01). Es zeigt sich ein optimaler
Cut-Off-Wert bei 2. Die Area under the curve (AUC) liegt bei 0,92 und liefert
Evidenz für eine sehr gute Diskriminierungsfähigkeit.

Diskussion und Schlussfolgerung Die Studie liefert Evidenz für
einen Einsatz des G-Score Item #3 als Screeninginstrument für
Schlafbeschwerden. Das Item zeigt zufriedenstellende Gütekriterien bei
maximaler Ökonomie.
Ultrasound Criteria for Diagnosing Spontaneous Cervical Artery Dissections
Authors: Arning Christian
Published: February 2023

Spontaneous dissection of brain-supplying cervical arteries, which also includes findings after minor injuries, is one of the main causes of ischaemic strokes in young adults. Strokes due to dissection are usually due to arterio-arterial embolism. They are rarely the first symptom of dissection because an intraluminal thrombus must first develop. Therefore, early diagnosis of dissection can contribute to stroke prevention – through immediate therapy with anticoagulants or antiplatelet drugs. This article describes the diagnostic criteria and typical findings of spontaneous dissection, in which no dissecting membrane is to be expected as in aortic dissection. Traumatic dissections following blunt or penetrating injuries also present with different findings. Examiners should be aware of possible differential diagnoses whose ultrasound image may mimic a dissection. A frequently occurring but avoidable cause of misdiagnosis is idiopathic carotidynia. Ultrasound also enables differentiation between dissection and vasculitis or carotid web and detection of normal variants such as fenestration of the vertebral artery. Further possibilities for misdiagnosis may arise in the presence of a variant of the ascending pharyngeal artery or in extracranial vasospasm. The different imaging techniques for the detection of a dissection are complementary, as false-negative findings occur with all techniques; no method serves as the gold standard. In any case, ultrasound can make an important contribution to the detection of a dissection, and it is worth knowing the diagnostic criteria.
Intramolecular Cyclization of N-Propargylic Amides without Transition-Metal Catalysis for Synthesis of Fluoroalkylated Oxazoles: Using Carboxylic Acid Anhydrides as the Fluoroalkyl Source
Authors: Amii Hideki , Sugiishi Tsuyuka , Motegi Ryohei
Published: February 2023

Synthesis of 2-fluoroalkylated oxazoles was developed by transition-metal-free intramolecular cyclization of N-propargylic amides, which are prepared from propargylic amines by employing a small excess of commercially available fluorocarboxylic acid anhydrides as fluoroalkyl­ sources, under basic conditions. Oxazoles bearing a trifluoro­methyl, pentafluoroethyl, or heptafluoropropyl group at the C2 position and functional groups on the C4 and/or C5 positions are obtained in moderate to high yields by controlling the reaction conditions.
Structure–Activity Relationships for Hypervalent Iodine Electrocatalysis
Authors: Powers David C. , Frey Brandon L. , Thai Phong , Patel Lauv
Published: February 2023

The design and optimization of novel electrocatalysts requires robust structure–activity data to correlate catalyst structure with electrochemical behavior. Aryl iodides have been gaining attention as metal-free electrocatalysts but experimental data are available for only a limited set of structures. Herein we report electrochemical data for a family of 70 aryl iodides. Half-peak potentials are utilized as proxies for reduction potentials and reveal that, despite differences in electrochemical reversibility, the potential for one-electron oxidation of 4-substituted aryl iodides to the corresponding iodanyl radicals is well-correlated with standard Hammett parameters. Additional data are presented for 3- and 2-substituted aryl iodides, including structures with potentially chelating 2-substituents that are commonly encountered in hypervalent iodine reagents. Finally, potential decomposition processes relevant to the (in)stability of iodanyl radicals are presented. We anticipate that the collected data will advance the design and application of aryl iodide electrocatalysis.
Incomplete resection rates of 4- to 20-mm non-pedunculated colorectal polyps when using wide-field cold snare resection with routine submucosal injection
Authors: Motchum Leslie , Djinbachian Roupen , Rahme Elham , Taghiakbari Mahsa , Bouchard Simon , Bouin Mickaël , Sidani Sacha , Deslandres Érik , Takla Mark , Frija-Gruman Nissim Max , Barkun Alan , von Renteln Daniel
Published: February 2023

Background and study aims Incomplete resection of 4- to 20-mm colorectal polyps occur frequently (> 10 %), putting patients at risk for post-colonoscopy colorectal cancer. We hypothesized that routine use of wide-field cold snare resection with submucosal injection (CSP-SI) might reduce incomplete resection rates (IRRs).

Patients and methods Patients aged 45 to 80 years undergoing elective colonoscopies were enrolled in a prospective clinical study. All 4- to 20-mm non-pedunculated polyps were resected using CSP-SI. Post-polypectomy margin biopsies were obtained to determine IRRs through histopathology assessment. The primary outcome was IRR, defined as remnant polyp tissue found on margin biopsies. Secondary outcomes included technical success and complication rates.

Results A total of 429 patients (median age 65 years, 47.1 % female, adenoma detection rate 40 %) with 204 non-pedunculated colorectal polyps 4 to 20 mm removed using CSP-SI were included in the final analysis. CSP-SI was technical successful in 97.5 % (199/204) of cases (5 conversion to hot snare polypectomy). IRR for CSP-SI was 3.8 % (7/183) (95 % confidence interval [CI] 2.7 %-5.5 %). IRR was 1.6 % (2/129), 16 % (4/25), and 3.4 % (1/29) for adenomas, serrated lesions, and hyperplastic polyps respectively. IRR was 2.3 % (2/87), 6.3 % (4/64), 4.0 % (6/151), and 3.1 % (1/32) for polyps 4 to 5 mm, 6 to 9 mm, < 10 mm, and 10 to 20 mm, respectively. There were no CSP-SI-related serious adverse events.

Conclusions Use of CSP-SI results in lower IRRs compared to what has previously been reported in the literature for hot or cold snare polypectomy when not using wide-field cold snare resection with submucosal injection. CSP-SI showed an excellent safety and efficacy profile, however comparative studies to CSP without SI are required to confirm these results.
Is Minimally Invasive Spinal Surgery Superior to Endoscopic Spine Surgery in Postoperative Radiologic Outcomes of Lumbar Spine Degenerative Disease? A Systematic Review
Authors: Patel Kashyap , Harikar Mandara Muralidhar , Venkataram Tejas , Chavda Vishal , Montemurro Nicola , Assefi Marjan , Hussain Namath , Yamamoto Vicky , Kateb Babak , Lewandrowski Kai-Uwe , Umana Giuseppe E.
Published: February 2023

Background Minimally invasive spinal surgery (ESS) are both well-established surgical techniques for lumbar spinal stenosis; however, there is limited literature comparing the efficacy of the two techniques with respect to radiologic decompression data.

Methods In this review, PubMed, Google Scholar, and Scopus databases were systematically searched from inception until July 2022 for studies that reported the radiologic outcomes of endoscopic and minimally invasive approaches for decompressive spinal surgery, namely, the spinal canal area, neural foraminal area, and neural foraminal heights.

Results Of the 378 articles initially retrieved using MeSH and keyword search, 9 studies reporting preoperative and postoperative spinal areas and foraminal areas and heights were finally included in our review. Of the total 581 patients, 391 (67.30%) underwent MISS and 190 (32.70%) underwent ESS. The weighted mean difference between the spinal canal diameter in pre- and postoperative conditions was 56.64 ± 7.11 and 79.52 ± 21.31 mm2 in the MISS and ESS groups, respectively. ESS was also associated with a higher mean difference in the foraminal area postoperatively (72 ± 1 vs. 35.81 ± 11.3 mm2 in the MISS and ESS groups, respectively), but it was comparable to MISS in terms of the foraminal height (0.32 ± 0.037 vs. 0.29 ± 0.03 cm in the MISS and endoscopic groups, respectively).

Conclusions Compared with MISS, ESS was associated with improved radiologic parameters, including spinal canal area and neural foraminal area in the lumbar spinal segments. Both techniques led to the same endpoint of neural decompression when starting with a more severe compression. However, the present data do not allow the correlation of the radiographic results with the related clinical outcomes.
Adherence and Cost Effectivity of Home-Based Prophylaxis Over Institutionalized Prophylaxis in Patients with Hemophilia
Authors: Dutta Anupam , Boruah Dipjyoti , Boruah Angshuman , Das Arijit
Published: February 2023

Purpose:

Home-based prophylaxis in hemophilia facilitates the treatment of patients with hemophilia (PwH) at home resulting in an improved quality of life, experiencing less pain and greater flexibility in daily activities. This literature studies the cost effectivity and adherence to prophylaxis treatment after the implementation of home-based prophylaxis therapy in PwH registered under the Hemophilia Treatment Centre (HTC) of Assam Medical College and Hospital.

Materials and Methods:

PwH and their parents were advised for self/home infusion after being trained by a medical professional for 6 months. Data were collected on the skip in prophylaxis treatment by PwH and their traveling cost to access the prophylaxis treatment before and after the implementation of home infusion, through questionnaire and telephonic interview.

Results:

The mean number of days of skip in prophylaxis was significantly reduced from 25 (±11) to 4 (±2) days after implementation of home infusion. The mean transportation cost was also found to be significantly decreased from Rs. 3297 (±2251) to 440 (±279). Before home/self-infusion, 77% of the registered PwH were found to skip prophylaxis doses more than 12 times a year but after home infusion, no PwH were found to skip more than 12 doses a year.

Conclusion:

Home therapy facilitates the PwH to strictly adhere to the prophylaxis regime significantly reducing the skipping of doses to be administered to the PwH. The risks of regular traveling and the burden of transportation expenditure to avail the prophylaxis treatment was also found to be reduced significantly.
Diagnosis and Management of Cystic Fibrosis Exacerbations
Authors: Milinic Tijana , McElvaney Oliver J. , Goss Christopher H.
Published: February 2023

With the improving survival of cystic fibrosis (CF) patients and the advent of highly effective cystic fibrosis transmembrane conductance regulator (CFTR) therapy, the clinical spectrum of this complex multisystem disease continues to evolve. One of the most important clinical events for patients with CF in the course of this disease is acute pulmonary exacerbation (PEx). Clinical and microbial epidemiology studies of CF PEx continue to provide important insight into the disease course, prognosis, and complications. This work has now led to several large-scale clinical trials designed to clarify the treatment paradigm for CF PEx. The primary goal of this review is to provide a summary and update of the pathophysiology, clinical and microbial epidemiology, outcome and treatment of CF PEx, biomarkers for exacerbation, and the impact of highly effective modulator therapy on these events moving forward.
Low-loss strong index modulated ultra-thermally stable optical phase-change material for broadband nonvolatile photonics
Authors: Li Ming , Li Shubing , Deng Menghan , Xu Xionghu , Dai Kai , Cui Anyang , Zhou Xin , Jiang Kai , Shang Liyan , Li Yawei , Zhang Jinzhong , Zhu Liangqing , Chu Junhao , Hu Zhigao
Published: February 2023

Optical phase change materials (O-PCMs) have attracted increasing attention and provide promising solutions for non-volatile reconfigurable photonics due to their large index contrast and non-volatile switching characteristics. In this work, we have explored the optical phase change properties of a dozen different O-PCMs and established the corresponding gene bank. Among these O-PCMs, Ge1Sb2Se3Te1 (G1S2S3T1) films exhibit unprecedented low-loss, strong light modulation capability, and ultra-thermal stability capability, which are prepared by pulsed laser deposition. Meanwhile, we investigate the phase transition kinetic mechanism of G1S2S3T1 films by transmission electron microscope, temperature dependent transmission spectroscopy, and temperature dependent Raman spectroscopy. It is found that the wide bandgap (1.09 eV) in the amorphous state, the large bandgap variation (0.51 eV) between amorphous and crystalline states, the needle-like configuration of its crystalline state, and the special phase change process contribute to strong refractive index modulation. Moreover, we find that their ultra-thermal stability is from a strong Sb–Se bond. Through the simulation, we found that G1S2S3T1 can be applied to prepare ultra-low loss waveguide devices. The present work represents a significant step in the development of broadband nonvolatile photonics derived from O-PCMs.
Low-temperature solution-processed nanoparticle-doped nickel oxide thin-film transistor
Authors: Chen Cihai , Chen Qizhen , Yang Qian , Chen Huipeng , Guo Tailiang
Published: February 2023

Developing p-type oxide thin-film transistors (TFTs) is an essential path for further application in complementary metal oxide semiconductor (CMOS) components. However, the inferior electrical performance of p-type MO TFTs compared to n-type TFTs remains an ongoing challenge. Herein, for the first time, a low temperature, facile material engineering approach by incorporating n-type nanoparticles (NPs) was proposed for preparing p-type transparent NiOx TFTs. The characteristics of thin films blending NPs and the electrical performances of TFTs were investigated. The field effect mobility of TFTs with doping was nearly 20 times higher than pristine TFTs without doping, which was mainly beneficial from the suitable band alignment between NPs and p-type oxide, the increasing Ni3+ oxidation state in NiOx, as well as the improved dielectric/semiconductor interface quality. Electrons from drain electrode injected into metal oxide turn accepted in NPs rather than being trapped in the dielectric/semiconductor interface due to a strong surface electron depletion effect of NPs. NPs with small particle size and appropriate concentration would promote continuous hole transport by electrons transferring and reducing the interface trap state. The facile material engineering strategy is a promising technique for preparing p-type transparent MO-TFTs at low temperature, which showed great potential to be applicable in CMOS circuits on flexible substrates.
Electron affinity of atomic scandium and yttrium and excited states of their negative ions
Authors: Zhang Rui , Lu Yuzhu , Tang Rulin , Ning Chuangang
Published: February 2023

The latest experimental electron affinity (EA) values of atomic scandium and yttrium were 0.189(20) and 0.308(12) eV as reported by Feigerle et al. in 1981. The measurement accuracy of these was far lower than that of other transition elements, and no conclusive result had been made on the excited states of their negative ions. In the current work, we report more accurate EA values of Sc and Y and the electronic structure of their negative ions using the slow-electron velocity-map imaging method. The EA values of Sc and Y are determined to be 0.179 378(22) and 0.311 29(22) eV, respectively. The ground state of Sc− is identified as 3 d4 s24 p 1 D2, and the ground state is 4 d5 s25 p 1 D2 for Y−. Furthermore, several excited states of Sc− and Y− are observed: Sc− (3 D1) and Y− (3 D1, 3 D2, 3 D3, 3 F2, and 3 F3), and their energy levels are determined to be 1131.8(28), 1210.0(13), 1362.3(30), 1467.7(26), 1747(16), and 1987(33) cm−1, respectively.
Theoretical study on spin-dependent zigzag-direction thermoelectric transport properties of Mn-doped blue phosphorene
Authors: Shi H. L. , Yang J. , Han Q. Z. , Ren Y. H. , Zhao Y. H. , He S. Y. , Gong L. J. , Jiang Z. T.
Published: February 2023

With the increasing demand for energy, it has become imperative to investigate the thermoelectric properties that can be beneficial to directly converting heat into electric energy. Here, we theoretically study the thermoelectric transport of the Mn-doped blue phosphorene (blue-P) along the zigzag direction. We show that the spin-polarized electronic transport in the blue-P can be produced by the Mn-doping induced half-metallic energy band structure, and the Seebeck coefficients can take positive and negative values, indicating that the main carriers may be holes and electrons. Thus, the spin-down, spin, and charge Seebeck coefficients show a high peak and a deep valley, while the spin and charge thermoelectric figures of merit show two wide peaks. Moreover, the spin and charge thermoelectric figures of merit are found to be so large that the Mn-doped blue-P along the zigzag direction can be used as good thermoelectric materials. In addition, we consider the effect of the doping concentration on the electronic structure and thermoelectric transport properties. This research should be an important reference for designing spin caloritronic and thermoelectric devices.
Differential absorption lidar data acquisition and control system for remote detection of trace chemicals including methane and thiodiglycol
Authors: Jindal M. K. , Mainuddin M. , Veerabuthiran S.
Published: February 2023

We report the design and development of a data acquisition and control system for high-speed acquisition of weak, backscattered differential signals and synchronized sequential operation of all subsystems of a tunable, mid-infrared Differential Absorption Lidar (DIAL) system. The presence of a low-level concentration of chemical species results in weak differential return signals. The differential signal also varies dynamically with respect to background atmospheric conditions. The challenge is to measure this low level of differential signal with high resolution and also control the sequence of operation of subsystems such as lasers and scanners for real time testing and evaluation in open field conditions. The concentration spread of the chemical species varies rapidly with distance. In order to capture this spatial variation, the lidar signal should be sampled and digitized at a high sampling rate. A customized Peripheral Component Interconnect based data acquisition of a 12-bit resolution, 30 Mega samples per second sampling rate, and an industrial personal computer-based control system has been realized. Detection algorithms and the firing sequence of the laser have been developed indigenously and implemented in the LabVIEW platform. The developed graphical user interface has various modes of operation as per user requirement and is capable of executing automatic operations for the developed DIAL system in order to detect and identify the chemicals. The performance has been evaluated by detecting the chemical species thiodiglycol at 800 m using 3190 and 3300 nm (online and offline wavelengths) with a differential cross-section of 2.5 × 10−23 m2. Similarly, methane has been detected and quantified with concentration of 2.2 ppm up to 300 m using 3316 and 3326 nm (online and offline wavelengths, respectively).
Polypyrrole modification on BiVO4 for photothermal-assisted photoelectrochemical water oxidation
Authors: Wu Jiazhe , Xu Xiaoya , Guo Xu , Xie Wensheng , Pan Lixia , Chen Yubin
Published: February 2023

The bismuth vanadate (BiVO4) photoanode receives extensive attention in photoelectrochemical (PEC) water splitting. However, the high charge recombination rate, low electronic conductivity, and sluggish electrode kinetics have inhibited the PEC performance. Increasing the reaction temperature for water oxidation is an effective way to enhance the carrier kinetics of BiVO4. Herein, a polypyrrole (PPy) layer was coated on the BiVO4 film. The PPy layer could harvest the near-infrared light to elevate the temperature of the BiVO4 photoelectrode and further improve charge separation and injection efficiencies. In addition, the conductive polymer PPy layer acted as an effective charge transfer channel to facilitate photogenerated holes moving from BiVO4 to the electrode/electrolyte interface. Therefore, PPy modification led to a significantly improved water oxidation property. After loading the cobalt–phosphate co-catalyst, the photocurrent density reached 3.64 mA cm−2 at 1.23 V vs the reversible hydrogen electrode, corresponding to an incident photon-to-current conversion efficiency of 63% at 430 nm. This work provided an effective strategy for designing a photothermal material assisted photoelectrode for efficient water splitting.
Accelerating the density-functional tight-binding method using graphical processing units
Authors: Vuong Van-Quan , Cevallos Caterina , Hourahine Ben , Aradi Bálint , Jakowski Jacek , Irle Stephan , Camacho Cristopher
Published: February 2023

Acceleration of the density-functional tight-binding (DFTB) method on single and multiple graphical processing units (GPUs) was accomplished using the MAGMA linear algebra library. Two major computational bottlenecks of DFTB ground-state calculations were addressed in our implementation: the Hamiltonian matrix diagonalization and the density matrix construction. The code was implemented and benchmarked on two different computer systems: (1) the SUMMIT IBM Power9 supercomputer at the Oak Ridge National Laboratory Leadership Computing Facility with 1–6 NVIDIA Volta V100 GPUs per computer node and (2) an in-house Intel Xeon computer with 1–2 NVIDIA Tesla P100 GPUs. The performance and parallel scalability were measured for three molecular models of 1-, 2-, and 3-dimensional chemical systems, represented by carbon nanotubes, covalent organic frameworks, and water clusters.
Optical spin-wave detection beyond the diffraction limit
Authors: Lucassen Juriaan , Peeters Mark J. G. , Schippers Casper F. , Duine Rembert A. , Swagten Henk J. M. , Koopmans Bert , Lavrijsen Reinoud
Published: February 2023

Spin waves are proposed as information carriers for next-generation computing devices because of their low power consumption. Moreover, their wave-like nature allows for novel computing paradigms. Conventional methods to detect propagating spin waves are based either on electrical induction, limiting the downscaling and efficiency complicating eventual implementation, or on light scattering, where the minimum detectable spin-wave wavelength is set by the wavelength of the laser unless near-field techniques are used. In this article, we demonstrate the magneto-optical detection of spin waves beyond the diffraction limit using a metallic grating that selectively absorbs laser light. Specifically, we demonstrate the detection of propagating spin waves with a wavelength of 700nm in 20nm thick Ni80Fe20 strips using a diffraction-limited laser spot with a diameter of 10μm. Additionally, we show that this grating is selective to the wavelength of the spin wave, providing phase-sensitive, wavevector-selective spin-wave detection in the time domain, thus providing a complementary approach to existing techniques such as Brillouin light scattering. This should open up new avenues toward the integration of the burgeoning fields of photonics and magnonics and aid in the optical detection of spin waves in the short-wavelength exchange regime for fundamental research.
The transition state region in nonsynchronous concerted reactions
Authors: Gómez Sara , Rojas-Valencia Natalia , Toro-Labbé Alejandro , Restrepo Albeiro
Published: February 2023

The critical and vanishing points of the reaction force F(ξ) = −dV(ξ)/dξ yield five important coordinates (ξR, ξR*, ξTS, ξP*, ξP) along the intrinsic reaction coordinate (IRC) for a given concerted reaction or reaction step. These points partition the IRC into three well-defined regions, reactants (ξR→ξR*), transition state (ξR*→ξP*), and products (ξP*→ξP), with traditional roles of mostly structural changes associated with the reactants and products regions and mostly electronic activity associated with the transition state (TS) region. Following the evolution of chemical bonding along the IRC using formal descriptors of synchronicity, reaction electron flux, Wiberg bond orders, and their derivatives (or, more precisely, the intensity of the electron activity) unambiguously indicates that for nonsynchronous reactions, electron activity transcends the TS region and takes place well into the reactants and products regions. Under these circumstances, an extension of the TS region toward the reactants and products regions may occur.
Molecular dynamics simulation studies of 1,3-dimethyl imidazolium nitrate ionic liquid with water
Authors: Solovyova Iana V. , Yang Shizhong , Starovoytov Oleg N.
Published: February 2023

The fundamental understanding of intermolecular interactions of ionic liquids (ILs) with water is essential in predicting IL–water thermodynamic properties. In this study, intermolecular or noncovalent interactions were studied for 1,3-dimethyl imidazolium [DMIM]+ cation and nitrate [NO3]− anion with water, employing quantum mechanics and molecular dynamics simulations. Molecular dynamics simulations were performed using a revised multipolar polarizable force field. The effect of water on ionic liquids was evaluated in terms of thermodynamic and dynamic properties. Thermodynamic properties included liquid densities ρ, excess molar volumes ΔVE, and liquid structures gr. Dynamic properties included self-diffusion coefficients D of mixture constituents as a function of water concentration. The density of ionic liquid–water mixtures monotonically decrease with increasing concentration of water. A negative excess volume was obtained for low and high water concentrations, demonstrating strong intermolecular interactions of water with ionic liquid components. Liquid structures of ionic liquid–water mixtures revealed a tendency for anions to interact with cations at shorter intermolecular distances when the water concentration is increased. Diffusion rates were found to increase for all mixture components with increase in the fraction of water. A significant change in the diffusion rate was found at ∼0.3 weight fraction of water. However, the water self-diffusion coefficient was dominant at all concentrations. The ratio of water/anion and anion/cation self-diffusion coefficients was found to decrease linearly with increasing concentration of water molecules.
Coalbed methane enrichment prediction and resource estimation for the areas with different tectonic complexities
Authors: Ye Zhenni , Liu Hao , Long Qijian
Published: February 2023

Geological tectonic movement plays a controlling role in the distribution pattern of coalbed methane (CBM) resources. The traditional CBM resource estimation methods use the measured CBM as the overall CBM content and do not consider the influence of geological structure on the nonuniform distribution of CBM resources. In this paper, the geological structure of the Guojiahe coalfield in the northern Yonglong mining area, China, was used as the research background. Based on the precise three-dimensional (3D) seismic interpretation results of the coal seam geological structure and the tested CBM contents at sampling points, a fuzzy comprehensive evaluation method was used to classify the tectonic complexity of the study area, and the CBM contents of different tectonic locations in the tested coal seams and the results determined by the finite element method were analyzed. On this basis, a quantitative relationship between the tectonic complexity index and the amount of CBM resources was established, and finally, a CBM-enrichment prediction model and a CBM resource estimation method for areas with different tectonic complexities were proposed. The agreement between the amount of CBM resources obtained by the estimation method and the actual exploration result is 85.2%; therefore, the proposed method has a theoretical guidance and engineering application value for the exploration and precise development of CBM resources.
Predicting climatic tipping points
Authors: Sunny Eros M. , Balakrishnan Janaki , Kurths Jürgen
Published: February 2023

Increased levels of greenhouse gases in the atmosphere, especially carbon dioxide, are leading contributors to a significant increase in the global temperature, and the consequent global climatic changes are more noticeable in recent years than in the past. A persistent increased growth of such gases might lead to an irreversible transition or tipping of the Earth’s climatic system to a new dynamical state. A change of regimes in CO2 buildup being correlated to one in global climate patterns, predicting this tipping point becomes crucially important. We propose here an innovative conceptual model, which does just this. Using the idea of rate-induced bifurcations, we show that a sufficiently rapid change in the system parameters beyond a critical value tips the system over to a new dynamical state. Our model when applied to real-world data detects tipping points, enables calculation of tipping rates and predicts their future values, and identifies thresholds beyond which tipping occurs. The model well captures the growth in time of the total global atmospheric fossil-fuel CO2 concentrations, identifying regime shift changes through measurable parameters and enabling prediction of future trends based on past data. Our model shows two distinct routes to tipping. We predict that with the present trend of variation of atmospheric greenhouse gas concentrations, the Earth’s climatic system would move over to a new stable dynamical regime in the year 2022. We determine a limit of 10.62 GtC at the start of 2022 for global CO2 emissions in order to avoid this tipping.
Behaviors of the reacting flowfield during the spontaneous formation of ramjet mode under a supersonic inflow
Authors: Wang Tai-Yu , Cai Zun , An Bin , Wang Jiao-Ru , Sun Ming-Bo , Liang Chang-Hai , Wang Zhen-Guo
Published: February 2023

This work experimentally studied the formation process of the ramjet mode occurring in a cavity-based combustor operating at a high-enthalpy supersonic flow. The ramjet mode is featured by the phenomenon that the incoming supersonic inflow is decelerated to be subsonic before it enters the combustor, which is caused by the strong heat release under a high equivalence ratio. In the experiments, the ignition is performed after a steady fuel mass flow rate has been achieved. According to the flame behavior and the flowfield structure, the formation process of the ramjet mode can be divided into three stages, among which stage 1 (from ignition to the cavity shear-layer mode) is shortest, while stage 3 (from the lifted shear-layer mode to the ramjet mode) consumes the longest time. In stage 2, flashback occurs and shock–shock interactions are found to be strongly coupled with the local combustion which have an influence on the propagation velocity of the backpressure. A thickening boundary layer upstream of the separation shock is observed when the separation shock has interwoven with the jet-induced bow-shock. The thickening process could be extremely short (in 100 μs) before the thickened boundary layer separates, during which the propagation velocity of the backpressure can be apparently decelerated. The same phenomena shown in the supplementary experiments confirm that the thickening boundary layer and its deceleration effect on the propagation of the backpressure are not accidental but more likely to be inherent to the flashback occurring under a supersonic flow.
The stress release of morphological change on thermochromic properties of nitrogen-incorporated VO2 thin films
Authors: Wang Ding-Yeong , Lin Kuei-Chih , Lin Cheng-Li , Lin Chih-Yi , Juan Pi-Chun
Published: February 2023

VO2 thin films are fabricated by the reactive high power impulse magnetron sputtering technique. Their thermochromic properties are found to be greatly affected by the addition of nitrogen during the deposition process. These include an effect of localized surface plasmon resonance due to isolated island structures. Furthermore, low transition temperatures below 45 °C are observed due to oxygen-deficient conditions. Also, the transition temperature decreases with an increase in the thickness of the TiO2 buffer layer. The reduction in transition temperature could be as low as 39 °C with a solar modulating ability of 4% at a thicker buffer of 300 nm under a high gas ratio of 21.7% for nitrogen. The crystalline phase is identified by x-ray diffraction, showing that the intensity of monoclinic crystallites at a diffraction angle of 2θ = 27.8° for (011) phase decreases with an increase in the amount of nitrogen, whereas a relaxing shift is detected near the diffraction angle of 2θ = 37.0° for (2¯11) phase. Similar behavior is seen in the peak shift of the (004) phase for TiO2. The d-spacing of the crystallization phase with island structure is identified by high-resolution transmission electron microscopy. The evolution of stress release, which is strongly dependent on surface morphology, is consistent with x-ray pole figure representation. The visible transmittance and solar modulation ability as functions of the amount of nitrogen and the buffer thickness of TiO2 are discussed.
A distributed-order fractional stochastic differential equation driven by Lévy noise: Existence, uniqueness, and a fast EM scheme
Authors: Dong Jincheng , Du Ning , Yang Zhiwei
Published: February 2023

In this paper, we consider a distributed-order fractional stochastic differential equation driven by Lévy noise. We, first, prove the existence and uniqueness of the solution. A Euler–Maruyama (EM) scheme is constructed for the equation, and its strong convergence order is shown to be min{1−α∗,0.5}, where α∗ depends upon the weight function. Besides, we present a fast EM method and also the error analysis of the fast scheme. In addition, several numerical experiments are carried out to substantiate the mathematical analysis.
Recurrent neural network wind power prediction based on variational modal decomposition improvement
Authors: Shi Chongqing , Zhang Xiaoli
Published: February 2023

In order to avoid the problem that the traditional recurrent neural network (RNN) wind power prediction model cannot take into account both the law of wind power variation and the impact of sudden change factors, this paper proposes an improved cyclic neural network wind power prediction model based on variational modal decomposition (VMD). The VMD algorithm is used to decompose the output power of wind power into different frequency components and analyze the impact of different frequency components on the prediction model. Combined with the feature extraction ability of the neural network, it can reduce the impact of abrupt abnormal data on the prediction results and improve the real-time prediction accuracy of wind power. According to the historical data of an actual wind farm, the results show that the accuracy of the wind power prediction model based on VMD and the recurrent neural network is more than 85%, which is superior to the traditional RNN and the standard long short term memory wind power prediction model.
Highly efficient coherent detection of terahertz pulses based on ethanol
Authors: Xiao Wen , Zhang Minghao , Zhang Rui , Zhang Cunlin , Zhang Liangliang
Published: February 2023

Water-based terahertz (THz) coherent detection scheme has been recently proposed, which overcomes the bandwidth limitation or high probe laser power demand in solid-/gas-based schemes. Here, we report a highly efficient THz coherent detection method using ethanol with superior performances under the mechanism of four-wave mixing. We systematically investigate the energy ratios and relative polarizations between the THz-induced second harmonic and control second harmonic (CSH) beams and reveal that ethanol always exhibits significantly higher detection sensitivity than water. The coherent, incoherent, or hybrid detection mode can be flexibly switched by changing the CSH beam polarization. The enhanced sensitivity derives from the much larger third-order nonlinear coefficient and lower ionization potential of ethanol. In addition, for the ethanol–water mixtures with various concentrations, the THz coherent detection signals can always be decomposed into the linear superposition of those from pure ethanol and neat water at the sub-picosecond timescale, indicating the synergistic contribution of ethanol and water molecules in the mixture during the detection process. This work provides a valid method to significantly improve the sensitivity of the liquid-based coherent detection scheme and a research perspective for exploring the solute–solvent molecular interactions.
Direct numerical simulation of supersonic internal flow in a model scramjet combustor under a non-reactive condition
Authors: Fang Jian , Deng Xi , Chen Zhi X.
Published: February 2023

A Mach 1.5 non-reactive flow in a cavity-stabilized combustor of a model scramjet is studied via a direct-numerical simulation approach, and the analysis is focused on the interaction among boundary layer, free shear-layer above the cavity and shock wave. It is found that the impingement of the free shear-layer on the aft wall of the cavity leads to strong turbulence kinetic energy, high local pressure, and a fan of compression waves. The compression waves evolve into an oblique shock, which reflects between the upper and lower walls and interacts with the boundary layers attached to the two walls. The analysis of the turbulence production reveals that the amplification of turbulence in the core of the shear-layer and around the reattachment point is mainly due to the shear production, but the deceleration production mechanism presents a significant impact in the regions above the aft wall of the cavity and around the shock interaction points. The very low frequency commonly observed in shock wave/boundary layer interactions is not observed in the present research, which might be due to the low Reynolds number of the studied case.
Permeability and diffusion resistance of porous membranes: Analytical theory and its numerical test
Authors: Skvortsov Alexei T. , Dagdug Leonardo , Hilder Emily F. , Berezhkovskii Alexander M. , Bezrukov Sergey M.
Published: February 2023

This study is devoted to the transport of neutral solutes through porous flat membranes, driven by the solute concentration difference in the reservoirs separated by the membrane. Transport occurs through membrane channels, which are assumed to be non-overlapping, identical, straight cylindrical pores connecting the reservoirs. The key quantities characterizing transport are membrane permeability and its diffusion resistance. Such transport problems arising in very different contexts, ranging from plant physiology and cell biology to chemical engineering, have been studied for more than a century. Nevertheless, an expression giving the permeability for a membrane of arbitrary thickness at arbitrary surface densities of the channel openings is still unknown. Here, we fill in the gap and derive such an expression. Since this expression is approximate, we compare its predictions with the permeability obtained from Brownian dynamics simulations and find good agreement between the two.
Dislocation mechanisms in strengthening and softening of nanotwinned materials
Authors: Wang Han , Rimoli Julian J. , Cao Penghui
Published: February 2023

Twin boundary (TB) strengthening in nanotwinned metals experiences a breakdown below a critical spacing at which softening takes over. Here, we survey a range of nanotwinned materials that possess different stacking fault energies (SFEs) and understand the TB strengthening limit using atomistic simulations. Distinct from Cu and Al, the nanotwinned, ultralow SFE materials (Co, NiCoCr, and NiCoCrFeMn) intriguingly exhibit a continuous strengthening down to a twin thickness of 0.63 nm. Examining dislocation slip mode and deformation microstructure, we find the hard dislocation modes persist even when reducing the twin boundary spacing to a nanometer regime. Meanwhile, the soft dislocation mode, which causes detwinning in Cu and Al, results in phase transformation and lamellar structure formation in Co, NiCoCr, and NiCoCrFeMn. This study, providing an enhanced understanding of dislocation mechanism in nanotwinned materials, demonstrates the potential for controlling mechanical behavior and ultimate strength with broadly tunable composition and SFE, especially in multi-principal element alloys.
Optimization design of negative pressure adsorption car for internal defect detection of wind turbine blades on UAV
Authors: Sun Xingdong , Wu Wandi , Wang Jie , Xu Liangyuan , Jiang Rui , Sun Yan , Fang Liangfei
Published: February 2023

The wind turbine blade is the core component of the wind turbine. However, wind turbine blades will suffer fatigue and internal crack defects, which seriously affect the safety service performance in harsh environments. The current detection mode is mainly traditional manual detection and shutdown maintenance, with high risk and low efficiency. Therefore, this research proposed a method to conduct a non-stop online inspection of the wind turbine blade’s internal defects using ultrasonic inspection mounted unmanned aerial vehicle. As the vital component of this inspection system, the optimized design of the negative pressure adsorption car was carried out. The structural characteristics of the negative pressure adsorption car were determined experimentally, followed by multivariate analysis and an integrated development and performance test study of the test system. Based on the test results, the detection rate of this test system for internal wind power blade faults is 100%. This research offers novel concepts of and theoretical insights into the intelligent and security identification of internal flaws in wind turbine blades.
Manipulating exchange bias in Ir25Mn75/CoTb bilayer through spin–orbit torque
Authors: Liu Ruobai , Zhang Yiyang , Yuan Yuan , Lu Yu , Liu Tianyu , Chen Jiarui , Wei Lujun , Wu Di , You Biao , Zhang Wei , Du Jun
Published: February 2023

Manipulation of exchange bias (EB) via spin-current-induced spin–orbit torque (SOT) is of great importance in developing full electric control spintronic devices. Here, we report on SOT-dominant manipulation of the interfacial antiferromagnetic spins and the related perpendicular EB (PEB) in the IrMn/Co1-xTbx (CoTb) bilayers with various Tb contents. No matter the magnetization of the ferrimagnetic CoTb layer is Co-dominant or Tb-dominant; all the samples were perpendicularly magnetized, and spontaneous PEB could be established during the isothermal crystallization of the IrMn layer. The SOT-induced EB switching could be accomplished with assistance of an in-plane or out-of-plane external magnetic field, associated with a monotonic reduction of the EB switching fraction by increasing x. This phenomenon is attributed to weakening of the interfacial exchange coupling between the CoTb and IrMn layers as x is increased. These findings provide a way to design high energy-efficient spintronic devices by employing the antiferromagnet/ferrimagnet bilayers, which may have weak stray field and strong robustness in contrast to commonly used heavy-metal/ferromagnet/antiferromagnet trilayers.