bluuebunny/crossref_metadata_2025 huggingface dataset:
Epitaxial growth of one-dimensional different-diameter silver nanowires
Authors: Chen Mengmeng , Cai Yupeng , Wang Peijie , Fang Yan
Published: October 2021

With the increasing demand for higher-level functional nanodevices, there is a strong requirement for the fabrication of high-crystallinity composite nanowires, e.g., one-dimensional end-to-end different-diameter silver nanowires.
Thermal hysteresis controlled reconfigurable MoS2 nanomechanical resonators
Authors: Wang Zenghui , Yang Rui , Feng Philip X.-L.
Published: October 2021

Two-dimensional (2D) structures from layered materials have enabled a number of novel devices including reconfigurable resonant nanoelectromechanical systems (NEMS).
Dimensionality-driven metal–insulator transition in spin–orbit-coupled IrO2
Authors: Arias-Egido E. , Laguna-Marco M. A. , Piquer C. , Jiménez-Cavero P. , Lucas I. , Morellón L. , Gallego F. , Rivera-Calzada A. , Cabero-Piris M. , Santamaria J. , Fabbris G. , Haskel D. , Boada R. , Díaz-Moreno S.
Published: October 2021

IrO2 thin films with tunable electrical transport and magnetic behavior have been obtained through control of thickness.
Visible-light-mediated alkylation of 4-alkyl-1,4-dihydropyridines with alkenyl sulfones
Authors: Yue Fuyang , Dong Jianyang , Liu Yuxiu , Wang Qingmin
Published: October 2021

Herein we report a mild, general protocol for visible-light-mediated alkylation of 4-alkyl-1,4-dihydropyridines with alkenyl sulfones.
Metastable Zr/Hf-MOFs: the hexagonal family of EHU-30 and their water-sorption induced structural transformation
Authors: Perfecto-Irigaray Maite , Beobide Garikoitz , Calero Sofia , Castillo Oscar , da Silva Ivan , Gutierrez Sevillano J. José , Luque Antonio , Pérez-Yáñez Sonia , Velasco Leticia F.
Published: October 2021

Four new EHU-30 isoreticular compounds, based on amino-functionalized linkers and Zr and Hf metal centres are reported, in which H2O adsorption isotherms show an anomalous behaviour due to a localized structural transformation from EHU-30 to UiO-66.
Graphene oxide-mediated scalable preparation of heterostructured MoS2–MoO2/graphene nanohybrids for efficient energy storage and hydrogen evolution reaction
Authors: Lonkar Sunil P. , Alhassan Saeed M.
Published: October 2021

A scalable and solid-state method was developed to prepare MoS2–MoO2/graphene ternary nanohybrids for energy storage and electrocatalytic applications.
An ANN‐based channel modeling in 5G millimeter wave for a high‐voltage substation
Authors: Fu Zihao , Zhang Yu , Zhao Xiongwen , Du Fei , Geng Suiyan , Qin Peng , Zhou Zhenyu , Zhang Lei , Chen Suhong
Published: October 2021

In this work, an artificial neural network (ANN) based time‐varying channel modeling framework is proposed, including a playback model and a prediction model. The purpose of the ANN‐based modeling framework is to playback 5G measured radio channels at certain measurement positions, and further predict large scale channel parameters (LSCPs) at unmeasured positions with limited amount of measurement data. 28 GHz channel measurements were also conducted at a high‐voltage substation for the first time worldwide to meet with 5G radio system deployment for China Energy Internet. Meanwhile, the performance of the playback channels is evaluated by comparison with the measurements and traditional geometry based stochastic modeling (GBSM) simulated channels. An optimized radial basis function (ORBF) ANN is applied in the prediction model, and the predicted LSCPs are compared with the other approaches, which shows that the ORBF has the best performance. This work offers a solution to predict radio channels and parameters in case of big measured or simulated channel datasets.
The observed multiplicity properties of B-type stars in the Galactic young open cluster NGC 6231
Authors: Banyard G. , Sana H. , Mahy L. , Bodensteiner J. , Villaseñor J. I. , Evans C. J.
Published: October 2021

Context. It is well known that massive O stars are frequently (if not always) found in binary or higher-order multiple systems, but this fact has been less robustly investigated for the lower mass range of the massive stars, represented by B-type stars. Obtaining the binary fraction and orbital parameter distributions of B-type stars is crucial to understand the impact of multiplicity on the archetypal progenitor of core-collapse supernovae as well as to properly investigate formation channels for gravitational wave progenitors.

Aims. This work aims to characterise the multiplicity of the B star population of the young open cluster NGC 6231 through multi-epoch optical spectroscopy of 80 B-type stars.

Methods. We analyse 31 FLAMES/GIRAFFE observations of 80 B-type stars, monitoring their radial velocities (RVs) and performing a least-squares spectral analysis (Lomb-Scargle) to search for periodicity in those stars with statistically significant variability in their RVs.

Results. We constrained an observed spectroscopic binary fraction of 33 ± 5% for the B-type stars of NGC 6231, with a first order bias correction giving a true spectroscopic binary fraction of 52 ± 8%. Out of 27 B-type binary candidates, we obtained orbital solutions for 20 systems: 15 single-lined (SB1) and five double-lined spectroscopic binaries (SB2s). We present these orbital solutions and the orbital parameter distributions associated with them.

Conclusions. Our results indicate that Galactic B-type stars are less frequently found in binary systems than their more massive O-type counterparts, but their orbital properties generally resemble those of B- and O-type stars in both the Galaxy and Large Magellanic Cloud.
A virtual element discretization for the time dependent Navier–Stokes equations in stream-function formulation
Authors: Adak Dibyendu , Mora David , Natarajan Sundararajan , Silgado Alberth
Published: October 2021

In this work, a new Virtual Element Method (VEM) of arbitrary order k ≥ 2 for the time dependent Navier–Stokes equations in stream-function form is proposed and analyzed. Using suitable projection operators, the bilinear and trilinear terms are discretized by only using the proposed degrees of freedom associated with the virtual space. Under certain assumptions on the computational domain, error estimations are derived and shown that the method is optimally convergent in both space and time variables. Finally, to justify the theoretical analysis, four benchmark examples are examined numerically.
Reduzindo as transfusões de sangue em pacientes com artroplastia total primária do quadril: A eficácia dos testes rápidos de Hb e uma clínica especializada em anemia pré-operatória
Authors: Sandean Darren , Samaras Michail , Chatterji Urjit , Power Richard , Qureshi Hafiz
Published: October 2021

Objetivo A anemia pré-operatória em pacientes ortopédicos, está associada a maiores taxas de transfusão de sangue alogênico, resultando em desfechos mais desfavoráveis. Até 25% dos pacientes encaminhados para cirurgia ortopédica de grande porte, apresentam algum grau de anemia. O controle adequado do sangue do paciente no perioperatório é essencial, a fim de reduzir as sequelas da anemia e a necessidade de transfusões. Avaliamos a eficácia do teste rápido, em conjunto com uma clínica especializada no tratamento da anemia pré-operatória, com o objetivo de detectar e tratar a anemia dos pacientes a serem submetidos a artroplastia total primária do quadril.

Métodos A comparação das taxas totais de transfusão de sangue alogênico, foi realizada em pacientes submetidos a artroplastia total primária do quadril, antes e depois da implementação dos testes rápidos e da clínica especializada no tratamento da anemia pré-operatória ao longo de um ano. Também foi feita uma comparação entre os pacientes com anemia, que foram encaminhados para a clínica, com aqueles que não foram encaminhados. Foram revisados os níveis de hemoglobina pré-operatória, as taxas de transfusão de sangue alogênico e o tratamento clínico em 1.095 pacientes.

Resultados Houve uma redução significativa nas taxas de transfusão, em pacientes submetidos à ATQ primária, caindo de 10,0% para 6,2% (p <0,05, teste χ2), após a implementação do teste rápido e da clínica especializada em anemia pré-operatória. A taxa de transfusão de sangue alogênico para pacientes anêmicos tratados na clínica foi de 6,7%, em comparação com 26,9% para pacientes anêmicos no pré-operatório, que não foram tratados na clínica (p <0,05, teste exato de Fisher). Em média, o tratamento na clínica aumentou a taxa de hemoglobina dos pacientes em 20 g/L, passando de 104 g/L para 124 g/L p <0,001.

Conclusões O teste rápido, juntamente com a clínica especializada no tratamento da anemia pré-operatória, reduziu a necessidade de transfusão de sangue alogênico perioperatório, em pacientes submetidos a artroplastia total primária do quadril, proporcionando uma identificação rápida e um tratamento eficaz da anemia pré-operatória.
Deformidade de Madelung – Resultado estético e funcional do tratamento cirúrgico com osteotomia em cúpula do rádio distal e secção do ligamento de Vickers
Authors: Carvalho Marcos , Cardoso Pedro Sá , Alves Cristina , Balacó Inês , Ling Tah Pu , Matos Gabriel
Published: October 2021

Objetivo Avaliar o resultado estético e funcional do tratamento cirúrgico da deformidade de Madelung em idade pediátrica.

Método Estudo retrospectivo dos pacientes com deformidade de Madelung em idade pediátrica tratados cirurgicamente através de osteotomia em cúpula do rádio distal e secção do ligamento de Vickers entre 2015 e 2018. Foram incluídos doentes com tempo de seguimento pós-operatório mínimo de 12 meses. Foram analisados dados demográficos, técnica cirúrgica, resultados clínicos e radiográficos. A avaliação radiográfica pré e pós-operatória consistiu na medição da inclinação ulnar, do afundamento semilunar, do ângulo da fossa semilunar e do desvio palmar do carpo. A avaliação clínica pós-operatória consistiu na medição das amplitudes articulares do punho, escala visual analógica (EVA) e score Disabilities of the Arm, Shoulder and Hand (DASH).

Resultados Foram incluídos quatro pacientes, dois com Madelung idiopática e dois com displasia óssea, todos do sexo feminino e com doença bilateral. Foram operados 6 punhos, a idade mediana à data de cirurgia foi 15,5 anos, e o tempo mediano de seguimento pós-operatório foi de 37,5 meses. Na análise radiográfica pós-operatória, verificou-se uma correção média de 8,8 ± 7,5° da inclinação ulnar, de 3 ± 3,9 mm do afundamento semilunar, de 8,2 ± 6,6° do ângulo da fossa semilunar e de 4,7 ± 2,6 mm do desvio palmar do carpo. Na avaliação da amplitude articular média pós-operatória, registrou-se uma flexão de 75,8 ± 3,4°; extensão de 62,5 ± 14,1°; desvio radial de 25,7 ± 2,9°; desvio cubital de 40,0 ± 2,9; pronação de 88,3 ± 2,4°; supinação de 82,5 ± 2,5°. Registou-se EVA mediana para dor residual = 1, défice funcional = 0, prejuízo estético = 0, e recomendação de procedimento cirúrgico = 10. A mediana do score DASH foi 0.

Conclusão O tratamento da deformidade de Madelung através da osteotomia em cúpula do rádio distal e secção do ligamento de Vickers permite obter um excelente resultado estético e funcional.
Periodontitis and Helicobacter pylori Infection: Eradication and Periodontal Therapy Combination
Authors: Tsimpiris Athanasios , Grigoriadis Andreas , Tsolianos Ioannis , Moschos Ioannis , Goulis Dimitrios G. , Kouklakis Georgios
Published: October 2021

Objectives This study was aimed to assess (1) the prevalence of salivary and gastric Helicobacter pylori (HP) infection in patients with and without periodontitis, (2) the prevalence of HP infection in patients with periodontitis according to its clinical classification, (3) the effect of periodontitis treatment in patients with or without gastric HP infection, and (4) if gastric HP eradication in combination with periodontitis treatment influences periodontitis clinical outcome.

Materials and Methods Thirty-three adults with periodontitis treated by quadrant scaling and root planning (QSRP). The simplified plaque index (PI), bleeding on probing index (BOP), probing pocket depth (PPD), and clinical attachment level (CAL) were assessed pretreatment and 3 months of posttreatment. The patients were tested for oral and gastric HP. Gastric HP (+) patients received eradication therapy. A control group of 32 periodontically healthy volunteers was tested for oral and gastric HP. Saliva samples were evaluated by real-time polymerase chain reaction (rtPCR); gastric HP was detected by urea breath test (UBT).

Statistical Analysis Normality of variables assessed by the Kolmogorov–Smirnov test, while the differences of pre- and post-treatment were analyzed by paired samples t-test. Differences between subgroups were compared by a Student’s t-test or a Mann–Whitney U-test. Comparisons of nominal variables were made by Pearson’s Chi-square test.

Results No saliva samples were positive for HP. Gastric HP was detected in six patients with periodontitis and seven controls (p > 0.05). HP infection affected patients with higher disease stages and grades. All HP (+) patients underwent successful eradication treatment. All clinical periodontitis indices improved following QSRP. HP (+) patients who received QSRP as adjunctive to eradication treatment showed improvement in BOP (p < 0.001), PI (p < 0.013), and CAL (p < 0.004) compared with HP (−) patients who received QSRP alone.

Conclusion Periodontitis was not associated with gastric HP infection. Saliva was not a gastric HP supply reservoir. Gastric HP infection was associated with advanced stages and grades of periodontitis. Although all periodontal clinical markers improved after QSRP, BOP, PI, and CAL, they were further improved when combined with eradication treatment. Periodontal evaluation and treatment combined with HP eradication are recommended in patients with HP gastric infection.
Esthetic Rehabilitation of Anterior Dentition with Different Types of Ceramic Restorations: Two Case Reports
Authors: Krump Michal , Krumpova Zelmira
Published: October 2021

All-ceramic systems represent an excellent restorative alternative for fixed dental prostheses, single crowns, and veneers in the anterior dentition. With respect to improved mechanical properties, lithium disilicate ceramic material provide a broad range of indications, and extended veneers can serve as an alternative to full crowns. Although ceramic veneers represent a more conservative approach compared to crowns, the correct indication is essential to achieving the ideal outcome. The following case reports describe two types of fixed restorations of the anterior dentition: extended lithium disilicate ceramic veneers and lithium disilicate full crowns. Factors influencing treatment selection for each type of restorations are presented.
Osteoarticular Infection of the Shoulder Joint Due to Trichophyton Spp. in a Dog
Authors: Feline Julien Alexandre , Cabassu Julien Bernard
Published: October 2021

A 10-year-old Labrador Retriever was referred for persistent lameness due to chronic right shoulder pain, unresponsive to various pain management therapies. Radiographs indicated signs of severe degenerative changes in the joint. Synovial fluid analysis was not diagnostic. Septic arthritis was suspected based on computed tomography and clinical signs. Arthroscopy allowed joint exploration, tissue biopsies, and copious joint lavage. Trichophyton spp. proliferation was identified on antimicrobial culture and histological analysis on samples obtained during arthroscopy. Oral griseofulvin therapy was initiated. Two months later, the referring veterinarian decided to interrupt the treatment after a negative synovial culture despite persistent lameness. Euthanasia was elected upon after pain also appeared on the tarsus; a post-mortem exam was not authorized by the owner. The origin of the infection remains unclear as this patient had no skin lesions and its immunological status was unknown. However, dermatophytosis has been reported in healthy dogs without skin lesions. To the author's knowledge, this is the first report of an osteoarticular infection with a dermatophyte in a dog.
Using Machine Learning to Capture Quality Metrics from Natural Language: A Case Study of Diabetic Eye Exams
Authors: Fong Allan , Scoulios Nicholas , Blumenthal H. Joseph , Anderson Ryan E.
Published: October 2021

Background and Objective The prevalence of value-based payment models has led to an increased use of the electronic health record to capture quality measures, necessitating additional documentation requirements for providers.

Methods This case study uses text mining and natural language processing techniques to identify the timely completion of diabetic eye exams (DEEs) from 26,203 unique clinician notes for reporting as an electronic clinical quality measure (eCQM). Logistic regression and support vector machine (SVM) using unbalanced and balanced datasets, using the synthetic minority over-sampling technique (SMOTE) algorithm, were evaluated on precision, recall, sensitivity, and f1-score for classifying records positive for DEE. We then integrate a high precision DEE model to evaluate free-text clinical narratives from our clinical EHR system.

Results Logistic regression and SVM models had comparable f1-score and specificity metrics with models trained and validated with no oversampling favoring precision over recall. SVM with and without oversampling resulted in the best precision, 0.96, and recall, 0.85, respectively. These two SVM models were applied to the unannotated 31,585 text segments representing 24,823 unique records and 13,714 unique patients. The number of records classified as positive for DEE using the SVM models ranged from 667 to 8,935 (2.7–36% out of 24,823, respectively). Unique patients classified as positive for DEE ranged from 3.5 to 41.8% highlighting the potential utility of these models.

Discussion We believe the impact of oversampling on SVM model performance to be caused by the potential of overfitting of the SVM SMOTE model on the synthesized data and the data synthesis process. However, the specificities of SVM with and without SMOTE were comparable, suggesting both models were confident in their negative predictions. By prioritizing to implement the SVM model with higher precision over sensitivity or recall in the categorization of DEEs, we can provide a highly reliable pool of results that can be documented through automation, reducing the burden of secondary review. Although the focus of this work was on completed DEEs, this method could be applied to completing other necessary documentation by extracting information from natural language in clinician notes.

Conclusion By enabling the capture of data for eCQMs from documentation generated by usual clinical practice, this work represents a case study in how such techniques can be leveraged to drive quality without increasing clinician work.
Polarization splitting with cubic crystals evaluated with synchrotron radiation
Authors: Wallace M. S. , Haque S. H. , Presura R. , Pohl I. , Wojcik M.
Published: October 2021

X-ray polarization-splitting crystals separate incident x rays into two components with perpendicular polarization by Bragg reflections at 45° from paired sets of internal planes. Here, the polarization-splitting properties of a germanium crystal are verified using incompletely polarized synchrotron radiation. Cleaner data would have come from a beam with a higher degree of polarization, which is achievable with small changes in the experimental geometry.
Dynamics of coupled Kuramoto oscillators with distributed delays
Authors: Ross A. , Kyrychko S. N. , Blyuss K. B. , Kyrychko Y. N.
Published: October 2021

This paper studies the effects of two different types of distributed-delay coupling in the system of two mutually coupled Kuramoto oscillators: one where the delay distribution is considered inside the coupling function and the other where the distribution enters outside the coupling function. In both cases, the existence and stability of phase-locked solutions is analyzed for uniform and gamma distribution kernels. The results show that while having the distribution inside the coupling function only changes parameter regions where phase-locked solutions exist, when the distribution is taken outside the coupling function, it affects both the existence, as well as stability properties of in- and anti-phase states. For both distribution types, various branches of phase-locked solutions are computed, and regions of their stability are identified for uniform, weak, and strong gamma distributions.
Cinema:Snap: Real-time tools for analysis of dynamic diamond anvil cell experiment data
Authors: Biwer Christopher M. , Quan Andres , Huston Larissa Q. , Sturtevant Blake T. , Sweeney Christine M.
Published: October 2021

We developed tools and a workflow for real-time analysis of data from dynamic diamond anvil cell experiments performed at user light sources. These tools allow users to determine the phases of matter observed during the compression of materials in order to make decisions during an experiment to improve the quality of experimental results and maximize the use of scarce experimental facility time. The tools fill a gap in dynamic compression data analysis tools that are real-time, are flexible to the needs of high-pressure scientists, connect to automated processing of results, can be easily incorporated into workflows with existing tools and data formats, and support remote experimental data analysis workflows. Specific analytics developed include novel automated two-peak analysis for overlapping peaks and multiple phases, coordinated views of pressure and temperature values, full-compression contour plots, and configurable views of integrated x-ray diffraction. We present an experimental use case to show how the tools produce real-time analytics that help the scientists revise parameters for the next compression.
Gyrofluid simulation of an I-mode pedestal relaxation event
Authors: Manz P. , Silvagni D. , Grover O. , Happel T. , Eich T. , Griener M. ,   ASDEX Upgrade Team
Published: October 2021

The I-mode is an edge-localized mode (ELM)-free confinement regime showing enhanced heat confinement. Nevertheless, also in I-mode, events similar to ELMs—albeit less harmful to the divertor—can occur, relaxing the pedestal gradients. A global electromagnetic gyrofluid simulation of such a pedestal relaxation event (PRE) in I-mode conditions is presented and qualitatively compared with previous measurements of PREs in ASDEX Upgrade [Silvagni et al., Nucl. Fusion 60, 126028 (2020)]. The gyrofluid simulation shows a precursor-oscillation of the characteristic instability of the I-mode, the weakly coherent mode (WCM). Prior to the PRE, the drive of the WCM-precursor changes from drift-wave to interchange. A sudden jump in cross-phase between electron temperature and plasma potential fluctuations at the WCM scale leads to the transport enhancement of the PRE.
Contact passivation for defect mitigation in multi-dimensional perovskite interfaces
Authors: R. Sundheep , Jain Ankit
Published: October 2021

Multi-dimensional perovskite (MDP) interface consisting of a lower-dimensional (2D) perovskite phase sandwiched between a bulk (3D) perovskite layer and a charge transporting layer is being propounded as a feasible solution for enhancing the stability of perovskite solar cells (PSCs). Here, using first principles-based density functional theory calculations, we study the effect of interface anion engineering on the stability and electronic property of the MDP interfaces. We find that 2D–3D perovskite interfaces are highly stable and are immune to interfacial defect formation. Furthermore, interface chlorination helps in mitigating the deleterious effect of charge localization for antisite defects at these interfaces. For an interface between 2D-perovskite and a charge-extracting TiO2 layer, we find that interfacial anion engineering is instrumental in alleviating the lattice mismatch induced instability. We propose that opposed to interfacial defects, the hole localization arising due to the presence of interfacial halide at the pristine 2D-TiO2 interface is the major obstacle that needs to be overcome for achieving a defect immune MDP for realizing a PSC with ultrahigh stability and performance.
On the dynamics in chemical vapor deposition of InN
Authors: Hsu Chih-Wei , Deminskyi Petro , Persson Anton , Karlsson Matts , Pedersen Henrik
Published: October 2021

Epitaxial nanometer-thin indium nitride (InN) films are considered promising active layers in various device applications but remain challenging to deposit. We compare the morphological evolution and characterizations of InN films with various growth conditions in chemical vapor deposition (CVD) by both a plasma atomic layer deposition (ALD) approach and a conventional metalorganic CVD approach. Our results show that a time-resolved precursor supply is highly beneficial for deposition of smooth and continuous InN nanometer-thin films. The time for purging the reactor between the precursor pulses and low deposition temperature are key factors to achieve homogeneous InN. The gas exchange dynamics of the reactor is further studied using computational fluid dynamics. According to our study, 320 °C is found to be the upper temperature where the dynamics of the deposition chemistry can be controlled to involve only surface reactions with surface species. The results highlight the promising role of the ALD technique in realizing electronic devices based on nanometer-thin InN layers.
Thermal performance of diamond field-effect transistors
Authors: Lundh James Spencer , Shoemaker Daniel , Birdwell A. Glen , Weil James D. , De La Cruz Leonard M. , Shah Pankaj B. , Crawford Kevin G. , Ivanov Tony G. , Wong Hiu Yung , Choi Sukwon
Published: October 2021

In this report, the thermal performance of a hydrogen (H)-terminated diamond field-effect transistor (FET) is investigated using Raman spectroscopy and electrothermal device modeling. First, the thermal conductivity (κdiamond) of the active diamond channel was determined by measuring the temperature rise of transmission line measurement structures under various heat flux conditions using nanoparticle-assisted Raman thermometry. Using this approach, κdiamond was estimated to be 1860 W/m K with a 95% confidence interval ranging from 1610 to 2120 W/m K. In conjunction with measured electrical output characteristics, this κ was used as an input parameter for an electrothermal device model of an H-terminated diamond FET. The simulated thermal response showed good agreement with surface temperature measurements acquired using nanoparticle-assisted Raman thermometry. These diamond-based structures were highly efficient at dissipating heat from the active device channel with measured device thermal resistances as low as ∼1 mm K/W. Using the calibrated electrothermal device model, the diamond FET was able to operate at a very high power density of 40 W/mm with a simulated temperature rise of ∼33 K. Finally, the thermal resistance of these lateral diamond FETs was compared to lateral transistor structures based on other ultrawide bandgap materials (Al0.70Ga0.30N, β-Ga2O3) and wide bandgap GaN for benchmarking. These results indicate that the thermal resistance of diamond-based lateral transistors can be up to ∼10× lower than GaN-based devices and ∼50× lower than other UWBG devices.
Simulation of upward gas—hydrate slurry multiphase flow in a vertical concentric annulus for natural gas hydrate solid fluidization exploitation
Authors: Kang Qi , Song Shangfei , Yu Jiahan , Shi Bohui , Chen Yuchuan , Lv Xiaofang , Liu Yang , Bai Zonghan , Hong Bingyuan , Wang Wei , Gong Jing
Published: October 2021

The accurate simulation of upward multiphase flow of hydrate slurry in the annulus is one of the key scientific unsolved issues in natural gas hydrate solid fluidization exploitation. In this work, the upward multiphase flow of hydrate slurry in a vertical concentric annulus is simulated. The hydrate slurry hydrodynamic models suitable for pseudo-single-phase flow, bubbly flow, slug flow, and annular flow are proposed, respectively. Finally, the hydrate decomposition kinetic model is combined with the established annulus hydrate slurry multiphase flow model to simulate the multiphase flow of hydrate slurry in the annulus. The factors affecting flow behaviors are analyzed. During the upward flow in the annulus, the hydrate slurry temperature first decreases and then increases. As the inlet temperature increases, the fluid temperature, hydrate decomposition rate, and gas superficial velocity increase. During the upward flow in the annulus, hydrate may be formed again, which indicates that the error may be magnified due to ignoring hydrate formation. The larger the flow rate, the smaller the length of the slug flow. The larger the hydrate volume fraction, the higher the starting point of hydrate decomposition. These findings are of practical value to give a further understanding of hydrate slurry multiphase flow, which can promote further engineering application of natural gas hydrate solid fluidization exploitation.
Low loss fishnet metamaterial via self-rolled nanotechnology
Authors: Briukhanova Daria , Habib Mohsin , Issah Ibrahim , Caglayan Humeyra
Published: October 2021

We propose and demonstrate the fabrication of a curved fishnet metamaterial integrated into a rolled-up tube (RUT) that consists of eight alternating layers of gold and silicon dioxide. We adopt a self-rolled technique for the fabrication of metal/dielectric microtubes with large enough diameters for optical characterization. We experimentally characterize the fabricated fishnet structure, and by means of numerical calculations, we show that the fabricated structure possesses a negative refractive index with a high figure of merit. We demonstrate that the negative refractive index region can be tuned by precisely controlling the dimensions of the holes forming the metamaterial. The results of this study open up the possibility to obtain a simple, fast, and flexible platform for the fabrication of RUT-based metamaterials for bioimaging and sensing applications.
Interaction of two out-of-phase underwater explosion bubbles
Authors: Liu Nian-Nian , Zhang A-Man , Cui Pu , Wang Shi-Ping , Li Shuai
Published: October 2021

This study presents an experimental investigation of the dynamic properties of underwater explosion (UNDEX) bubble pairs produced with a range of phase differences Δθ, defined as 2π(t1−t2)/Tosc, where ti (i = 1,2) represents the bubble inception moment and Tosc is the experimentally obtained first period of a single UNDEX bubble. Each bubble was generated by a spherical hexogen explosive charge detonated in a cubical tank and observed via high-speed photography. The phase difference was adjusted by setting different delays between the two detonations, with an accuracy of 1.0 ms. Experiments were conducted with both horizontally and vertically positioned bubble pairs and with single bubbles as well. UNDEX bubble pairs are subject to a larger buoyancy effect than cavitation or spark-generated bubble pairs. The resultant bubble behavior in the bubble–bubble interaction is more complex and is yet to be understood. In our experiments, various bubble parameters, including bubble pulsation periods, bubble elongation ratios, and collapse-induced shock wave pressures bubble, were measured and studied. Dependence of the bubble dynamics on Δθ was found, demonstrating the significant influence of Δθ on the morphology and shock wave pressure of bubble pairs. The findings suggest a method of strengthening or weakening the damage potential of an UNDEX bubble pair based on the proper adjustment of the delay between two detonations. It may also lead to a better understanding of the dynamics of interacting bubbles with buoyancy effects.
Two-dimensional retrieval methods for ultrafast imaging of molecular structure using laser-induced electron diffraction
Authors: Wang Su-Ju , Daněk Jiří , Blaga Cosmin I. , DiMauro Louis F. , Biegert Jens , Lin C. D.
Published: October 2021

Molecular structural retrieval based on electron diffraction has been proposed to determine the atomic positions of molecules with sub-angstrom spatial and femtosecond temporal resolutions. Given its success on small molecular systems, in this work, we point out that the accuracy of structure retrieval is constrained by the availability of a wide range of experimental data in the momentum space in all molecular systems. To mitigate the limitations, for laser-induced electron diffraction, here we retrieve molecular structures using two-dimensional (energy and angle) electron momentum spectra in the laboratory frame for a number of small molecular systems, which have previously been studied with 1D methods. Compared to the conventional single-energy or single-angle analysis, our 2D methods effectively expand the momentum range of the measured data. Besides utilization of the 2D data, two complementary methods are developed for consistency check on the retrieved results. The 2D nature of our methods also offers a way of estimating the error from retrieval, which has never been explored before. Comparing with results from prior experiments, our findings show evidence that our 2D methods outperform the conventional 1D methods. Paving the way to the retrieval of large molecular systems, in which their tunneling ionization rates are challenging to obtain, we estimate the error of using the isotropic model in place of including the orientation-dependent ionization rate.
Bohmian trajectories of the time-oscillating Schrödinger equations
Authors: Li Dandan , Duan Jinqiao , Lin Li , Zhang Ao
Published: October 2021

Bohmian mechanics is a non-relativistic quantum theory based on a particle approach. In this paper, we study the Schrödinger equation with a rapidly oscillating potential and the associated Bohmian trajectory. We prove that the corresponding Bohmian trajectory converges locally in a measure, and the limit coincides with the Bohmian trajectory for the effective Schrödinger equation on a finite time interval. This is beneficial for efficient simulation of the Bohmian trajectories in oscillating potential fields.
Demand Response for Energy-Efficient and Optimal Integration of Renewable Energy Sources in a Smart Grid
Authors: Chaudhary Priyanka
Published: October 2021

In a smart grid, the integration of renewable energy sources (RESs) can be done by users who have the capacity to participate in demand-side management. This chapter presents a home energy management system that includes a management controller for efficient scheduling of household loads and integration of RESs. An energy management control system that depends on the genetic wind-driven optimization technique for scheduling the individual instruments and combined houses is presented in this chapter. Further, the proposed model has been compared with genetic algorithm, binary particle swarm optimization, wind-driven optimization, and other already available models. Real-time pricing and time of use are grouped to price the energy. Efficiently integrating the RESs into a smart grid is a big challenge because of the time-varying and infrequent nature of RESs. The proposed control gives quick responses under constant and variable scenarios. The results have also been compared with already present techniques. The developed system is demonstrated by using MATLAB/Simulink.
Global urban population exposure to extreme heat
Authors: Tuholske Cascade , Caylor Kelly , Funk Chris , Verdin Andrew , Sweeney Stuart , Grace Kathryn , Peterson Pete , Evans Tom
Published: October 2021

Significance

Increased extreme heat exposure from both climate change and the urban heat island effect threatens rapidly growing urban settlements worldwide. Yet, because we do not know where urban population growth and extreme heat intersect, we have limited capacity to reduce the impacts of urban extreme heat exposure. Here, we leverage fine-resolution temperature and population data to measure urban extreme heat exposure for 13,115 cities from 1983 to 2016. Globally, urban exposure increased nearly 200%, affecting 1.7 billion people. Total urban warming elevated exposure rates 52% above population growth alone. However, spatially heterogeneous exposure patterns highlight an urgent need for locally tailored adaptations and early warning systems to reduce harm from urban extreme heat exposure across the planet’s diverse urban settlements.
Eighteen-month-old infants represent nonlocal syntactic dependencies
Authors: Perkins Laurel , Lidz Jeffrey
Published: October 2021

Significance

As mature speakers of a language, we are able to produce and understand an indefinite number of sentences. This ability comes from a powerful cognitive system—syntax—whose properties reveal the types of computations that human minds can engage in. One core property is the capacity to encode abstract grammatical dependencies that can hold at a distance. When does this property emerge in development? We identify a nonlocal dependency that 18-mo-old infants, but not younger infants, represent syntactically. These findings suggest that the second year of life is a period of active syntactic development and that even before they regularly produce full sentences of their own, infants demonstrate some of the core computational capacities that syntax relies on.
Cerebral and systemic physiological effects of wearing face masks in young adults
Authors: Fischer Jonas B. , Kobayashi Frisk Lisa , Scholkmann Felix , Delgado-Mederos Raquel , Mayos Mercedes , Durduran Turgut
Published: October 2021

The COVID-19 pandemic led to widespread mandates requiring the wearing of face masks, which led to debates on their benefits and possible adverse effects. To that end, the physiological effects at the systemic and at the brain level are of interest. We have investigated the effect of commonly available face masks (FFP2 and surgical) on cerebral hemodynamics and oxygenation, particularly microvascular cerebral blood flow (CBF) and blood/tissue oxygen saturation (StO
2
), measured by transcranial hybrid near-infrared spectroscopies and on systemic physiology in 13 healthy adults (ages: 23 to 33 y). The results indicate small but significant changes in cerebral hemodynamics while wearing a mask. However, these changes are comparable to those of daily life activities. This platform and the protocol provides the basis for large or targeted studies of the effects of mask wearing in different populations and while performing critical tasks.
Adolescent civic engagement: Lessons from Black Lives Matter
Authors: Baskin-Sommers Arielle , Simmons Cortney , Conley May , Chang Shou-An , Estrada Suzanne , Collins Meghan , Pelham William , Beckford Emil , Mitchell-Adams Haley , Berrian Nia , Tapert Susan F. , Gee Dylan G. , Casey B. J.
Published: October 2021

In 2020, individuals of all ages engaged in demonstrations condemning police brutality and supporting the Black Lives Matter (BLM) movement. Research that used parent reports and trends commented on in popular media suggested that adolescents under 18 had become increasingly involved in this movement. In the first large-scale quantitative survey of adolescents’ exposure to BLM demonstrations, 4,970 youth (mean
age
= 12.88 y) across the United States highlighted that they were highly engaged, particularly with media, and experienced positive emotions when exposed to the BLM movement. In addition to reporting strong engagement and positive emotions related to BLM demonstrations, Black adolescents in particular reported higher negative emotions when engaging with different types of media and more exposure to violence during in-person BLM demonstrations. Appreciating youth civic engagement, while also providing support for processing complex experiences and feelings, is important for the health and welfare of young people and society.
Revisiting Laser-Intensity-Dependent Ionization and Fragmentation of C60
Authors: Dong D. P. , Yang B. H. , Qian D. B. , Zhou W. C. , Zhang S. F. , Ma X.
Published: October 2021

We revisit the laser-intensity-dependent ionization and fragmentation yields of C60 molecules irradiated by 25-fs, 798-nm laser pulses based on the approach in which photoions are measured via a velocity map imaging spectrometer working in a time-sliced mode. This approach dramatically improves the signal-to-background ratio compared to those using a simple (traditional) time-of-flight mode (spectrometer), and thus allows us to measure the laser-intensity dependences down to a previously untouched region, which is expected to provide new insights into the intense-field ionization and fragmentation of C60. Indeed, we find that the saturation intensities for C60 ionizations and the onset intensity for C60 fragmentation are much lower than those reported in previous experiments. Furthermore, the derived saturation-intensity dependence on charge distribution demonstrates the validity of the over-the-barrier ionization using a conducting sphere model.
Synergistic Influences of Kinetic Effects from Thermal Particles and Fast Ions on Internal Kink Mode
Authors: Miao Yutian , Hao G. Z. , Liu Yue , He H. D. , Chen W. , Wang Y. Q. , Wang A. K. , Xu M.
Published: October 2021

The kinetic effects of thermal particles and fast ions on internal kink (IK) mode are numerically investigated by the MHD-kinetic hybrid code MARS-K. It is shown that either thermal particles or fast ions have stabilizing influence on IK. However, the former can not fully stabilize IK, and the later can suppress the IK. In addition, the synergistic effect from thermal particles and fast ions induces more stronger damping on IK. The kinetic effects from particles significantly raise the critical value of poloidal beta (

β
p

crit

) for driving IK in the toroidal plasma. This implies a method of controlling IK or sawtooth in the high-β
p discharge scenario of tokamak. It is noted that, at the q = 1 rational surface, mode structure becomes more sharp due to the self-consistent modification by particles’ kinetic effect.
Characterization and operational stability of EJ276 plastic scintillator-based detector for neutron spectroscopy
Authors: McCormack O. , Giacomelli L. , Croci G. , Muraro A. , Gorini G. , Grosso G. , Pasqualotto R. , Perelli Cippo E. , Rebai M. , Rigamonti D. , Tardocchi M.
Published: October 2021

A state-of-the-art EJ276 plastic scintillator-based detector
for neutron spectroscopy has undergone detailed characterization
both in a controlled laboratory and on-site at the SPIDER negative
ion source facility in Padua. The device will be used for the
spectroscopy of 2.5 MeV neutrons produced from Deuterium-Deuterium
fusion reactions occurring inside the SPIDER beam dump. A plastic
based scintillator with neutron/gamma discrimination has some key
advantages over the commonly used organic liquid scintillators with
regards economic cost and handling safety. The purpose of this
characterization is to determine the operational functionality and
reliability of this new breed of detector material. Several tests
were performed to verify expected operation with regards to signal
reproducibility, long-term stability, and pulse shape discrimination
(PSD) capabilities. It was found that the detector system (EJ276
scintillator + photomultiplier tube) performed well in terms of
reproducibility and PSD, however the long-term stability of the
scintillator light output was seen to diminish considerably over
time (>50% decrease) and must be consistently
monitored in order to have an accurate conversion scale needed for
energy spectroscopy.
High-voltage pulse modulated radio frequency generator for dielectric barrier discharge combined with ultra-fast high power pulse generator
Authors: Flaxer E.
Published: October 2021

Dielectric barrier discharge is the electrical discharge
between two electrodes separated by an insulating dielectric
barrier. The discharge process typically uses a high-voltage
alternating current in the range of several kilohertz to several
gigahertz. A high-frequency and high-power pulse generator is
required to drive the discharge process through the capacitance
load. There are two main techniques to implement this type of
generator: the forced and resonant modes. This work demonstrates the
implementation of a programmable digital circuit based on a digital
signal controller and a full H-bridge that combines the two
topologies and can be used as a controller for dielectric barrier
discharge with varying capacitance and structure. We integrated an
ultra-fast, high-resolution, and high-power pulse generator into a
radio frequency generator to drive high-pressure, supersonic, pulsed
valves. The excitation based on our DBD and the combined generator
produces cold plasma beams. The controller generates discharge
voltages of up to 5 kV, in pulses of 10 to 50 μs wide, at
rates of up to 1 kHz, while the discharge frequency ranges are from
1 to 3 MHz under a capacitive load of 100 pF. The power generator
applies a current pulse of up to 20 A and voltage of up to 150 V.
Diffusive hydrodynamics of inhomogenous Hamiltonians
Authors: Durnin Joseph , De Luca Andrea , De Nardis Jacopo , Doyon Benjamin
Published: October 2021

We derive a large-scale hydrodynamic equation, including diffusive and dissipative effects, for systems with generic static position-dependent driving forces coupling to local conserved quantities. We show that this equation predicts entropy increase and thermal states as the only stationary states. The equation applies to any hydrodynamic system with any number of local, parity and time-symmetric conserved quantities, in arbitrary dimension. It is fully expressed in terms of elements of an extended Onsager matrix. In integrable systems, this matrix admits an expansion in the density of excitations. We evaluate exactly its two-particle–hole contribution, which dominates at low density, in terms of the scattering phase and dispersion of the quasiparticles, giving a lower bound for the extended Onsager matrix and entropy production. We conclude with a molecular dynamics simulation, demonstrating thermalisation over diffusive time scales in the Toda interacting particle model with an inhomogeneous energy field.
Additional quantum numbers for two-electron states in solids. Application to topological superconductor UPt3
Authors: Yarzhemsky V G , Teplyakov E A
Published: October 2021

Topological superconductors, which are assumed to be a key ingredient for topological quantum computing, reveal unconventional structures of their superconducting order parameter (SOP), which is usually represented by model functions. However, the central problem of the theory of topological superconductivity is to describe the observed topological structures of SOP in terms of quantum mechanics and group theory. In present work making use of the Anderson ansatz for a Cooper pair and induced representation method a complete group theoretical classification of chiral states in D
6h
symmetry (point symmetry group of topological superconductor UPt3) is performed. In this technique topological invariant phase winding is defined by the complex irreducible representation (IR) of symmetry group D
6h
, whose structure strongly depends on additional quantum numbers, which are the labels of IRs of Cooper pair’s rotational symmetry group C
6h
. The technique is extended on the description of time reversal symmetry of the state in terms of Shubikov groups, and B phase of UPt3 with horizontal nodal plane only was connected with corepresentation

Δ

+

E

′

2
u

of magnetic group 6/mm′m′. The structure of A phase with vertical nodes 45° to a axis is a combinations of two complex conjugate E
2u
states. Twofold spontaneous symmetry breaking in C phase is connected with the E
1u
SOP.