bluuebunny/crossref_metadata_2025 huggingface dataset:
Flux weakening control of IPMSM traction system based on single current regulation square wave strategy
Authors: Zhang Weiwei , Xiao Fei , Liu Jilong , Lian Chuanqiang , Liu Cang
Published: November 2023

The interior permanent magnet synchronous motor traction system of rail vehicles usually needs to run above base speed. It is necessary to implement high‐efficiency flux weakening control of the traction motor. This paper presents one single current regulation square wave strategy, which can improve the dynamic performance of the flux weakening control of the interior permanent magnet synchronous motor traction system. By proposing a novel switching criterion and the modulation method, smooth switching between the maximum torque per ampere control below base speed and the square wave control above base speed can be realized. Simulation and experimental results demonstrate the correctness and effectiveness of the proposed control strategy.
Robust fault‐tolerant design for LC‐coupling hybrid active power filter
Authors: Yuan Lv , Lei Wang , Kai Zhang , Wei Tian , Jiawen Yu , Bing Gao
Published: November 2023

In this paper, an open‐circuit fault‐tolerant topology of LC‐coupling hybrid active power filter (LC‐HAPF) and its control strategy are proposed at the switch level, which can greatly improve the reliability of the system. The proposed structure has a contactor between the midpoint of each bridge arm and the negative bus of the dc‐link capacitor. When a single‐phase fault occurs, the proposed LC‐HAPF can be reconstructed into a three‐phase four‐switch system to compensate for the harmonic and reactive power, while the power quality compensation effect is hardly affected. When a two‐phase fault occurs, the operation of the normal bridge arm is not affected, and the two faulty bridge arms can suppress harmonic current and compensate for a fixed reactive power through the passive filters. When the bridge arms all fail, the whole device acts as a passive filter to suppress the harmonic current of the load and to compensate for reactive power as well. Finally, the effectiveness of the proposed topology and its control strategy is verified by simulation and experiment results.
A comparative study of combined cycles for concentrated solar power for efficient power generation using low Global Warming Potential (GWP) fluids to reduce environmental effects
Authors: Khan Yunis , Caliskan Hakan , Hong Hiki
Published: November 2023

A comparative analysis of a combined system comprising organic Rankine cycles (ORC) and supercritical CO2 (sCO2) cycles for concentrated solar power (CSP) applications was performed in the article. Low global warming potential (GWP) fluids were used to investigate strategies for reducing the effects on global warming. In the current study, four different combinations of the sCO2 cycles and ORC, including basic recuperated, pre‐compression, recompression with main compressor intercooling, and partial cooling, were taken into consideration, and their performances with regard to CSP application were compared. The integrated recompression with main compressor intercooling and ORC arrangement was seen to operate thermodynamically more efficient than the other considered configurations. This configuration's highest thermal and exergy efficiencies were discovered to be 51.9% and 55.84%, respectively, and R1243zf was found to be the best‐performing fluid among other considered low GWP fluids to reduce the environmental effects.
Ship HRRP target recognition against decoy jamming based on CNN‐BiLSTM‐SE model
Authors: Wu Lingang , Hu Shengliang , Xu Jianghu , Liu Zhong
Published: November 2023

Due to the thinner resolution range of broadband radar, ship recognition issues arise such that minor fluctuations within the targeted area significantly affect the high‐resolution range profile (HRRP) of ships. Especially in the presence of reflector decoys around the surroundings of a ship, the HRRP of mixed targets might take a vastly different shape than of single ship, which makes it difficult to capture the effective features for ship identification. This article proposes a novel radar target recognition model based on parallel neural networks. The framework of this model consists of two stages: the data preprocessing and the parallel neural network. The data preprocessing stage effectively solves the sensitivity issue of HRRP and maps one‐dimensional HRRP into a two‐dimensional image. The second stage employs CNN and bidirectional LSTM to extract overall envelope features and temporal features, respectively. The parallel features are then processed by the Squeeze Excitation (SE) block to enhance critical information. The experimental results, based on HRRP data from mixed targets of ships and reflector decoys, demonstrate that the proposed model outperforms other methods in recognition performance and is quite robust against small sample sets, high noise, and large amounts of decoy jamming.
Führen im Doppelpack
Authors: Ottenbreit Franziska
Published: November 2023

Die Kliniken stehen seit Jahren vor der Herausforderung, sich anzupassen, neu aufzustellen und durch Weiterentwicklung und Innovation den Anforderungen nachzukommen. Auch an der Pflege gehen diese Prozesse nicht vorbei. Pflegesituationen werden komplexer und die originären Pflegetätigkeiten weiten sich, im Sinne der Professionalisierung, aus.
Oxidation of Alcohols to Aldehydes and Ketones Using a Catalytic Pairing of a Nitroxide and Nitric Acid
Authors: Leadbeater Nicholas E. , Sharma Manisha , Sandoval Arturo León
Published: November 2023

A methodology for the oxidation of alcohols to aldehydes and ketones is presented. The approach employs catalytic quantities of a nitroxide and nitric acid, with no additives or metal catalysts being required. It proves effective for a range of aromatic, heteroaromatic, and aliphatic alcohol substrates, the desired products being formed in good to excellent yield. In the case of primary alcohols, the oxidation can be stopped at the aldehyde without concomitant formation of the corresponding carboxylic acid.
Management of Brain Metastases: A Review of Novel Therapies
Authors: Bellur Shreyas , Khosla Atulya Aman , Ozair Ahmad , Kotecha Rupesh , McDermott Michael W. , Ahluwalia Manmeet S.
Published: November 2023

Brain metastases (BMs) represent the most common intracranial tumors in adults, and most commonly originate from lung, followed by breast, melanoma, kidney, and colorectal cancer. Management of BM is individualized based on the size and number of brain metastases, the extent of extracranial disease, the primary tumor subtype, neurological symptoms, and prior lines of therapy. Until recently, treatment strategies were limited to local therapies, like surgical resection and radiotherapy, the latter in the form of whole-brain radiotherapy or stereotactic radiosurgery. The next generation of local strategies includes laser interstitial thermal therapy, magnetic hyperthermic therapy, post-resection brachytherapy, and focused ultrasound. New targeted therapies and immunotherapies with documented intracranial activity have transformed clinical outcomes. Novel systemic therapies with intracranial utility include new anaplastic lymphoma kinase inhibitors like brigatinib and ensartinib; selective “rearranged during transfection” inhibitors like selpercatinib and pralsetinib; B-raf proto-oncogene inhibitors like encorafenib and vemurafenib; Kirsten rat sarcoma viral oncogene inhibitors like sotorasib and adagrasib; ROS1 gene rearrangement (ROS1) inhibitors, anti-neurotrophic tyrosine receptor kinase agents like larotrectinib and entrectinib; anti-human epidermal growth factor receptor 2/epidermal growth factor receptor exon 20 agent like poziotinib; and antibody–drug conjugates like trastuzumab-emtansine and trastuzumab-deruxtecan. This review highlights the modern multidisciplinary management of BM, emphasizing the integration of systemic and local therapies.
Place of Plasma Argon Coagulation in the Treatment of Vascular Abnormalities of the Digestive Tract in Adults
Authors: Mrabti Samir , Benhamdane Ahlame , Sair Asmae , Addajou Tarik , Berrida Réda , Sentissi Sara , Koti Ilham , Rouibaa Fedoua , Benkirane Ahmed , Seddik Hassan
Published: November 2023

The aim of our study is to evaluate the value of Argon Plasma Coagulation in the treatment of gastrointestinal vascular abnormalities.

Patients and methods This is a descriptive and analytical retrospective study, from January 2009 to September 2020. 198 patients who have benefited from treatment with Argon Plasma Coagulation for vascular anomalies of the digestive tract divided into 2 groups:

-Group A: Patients with radial rectitis lesions (n = 107).

-Group B: Patients with lesions of digestive angiodysplasia (n = 91).

Results The mean age of our patients was 64.95 ± 9.88 years [43 - 83] in group A, while in group B the mean age was 65.19 ± 14.29 years [40 - 91] with a clear male predominance in 72.5%. The majority of patients in group A were followed for prostate cancer in 33,8%, and 26.3% of patients in group B had chronic renal failure, followed by stomach cancer in 15.8%, and esophageal cancer in 10.5%. Clinical symptomatology was dominated by rectories in 40.2% in group A versus 46.8% in group B. Rectal involvement was dominated in group A in 98.1%, whereas in group B the lesions were mainly located in the stomach in 60.5%. The endoscopic evolution was favorable in all our patients with a clear improvement of rectal lesions and digestive angiodysplasia lesions. The total complication rate in our series was nil.

Conclusion Plasma Argon coagulation is a very effective method in the endoscopic treatment of digestive haemorrhages with good tolerability and a low complication rate.
Development of a Low-Cost Simulator for Training in Hemorrhoidal Ligation
Authors: Cunha Carlos Magno Queiroz da , Costa João Víctor Liberalino , Pessoa Maria Valquídia Nogueira , Vidal Lavier Kelvin Holanda , Veras Lara Burlamaqui
Published: November 2023

Introduction Rubber band ligation is a minimally invasive outpatient hemorrhoid treatment with low cost, low complication rates, and rapid realization. It is performed with the aid of an anoscope and uses a rubber ring that surrounds the hemorrhoidal nipple, causing compression of the vascular structures of the tissue, leading to necrosis and remission of the hemorrhoid. No device for training this essential procedure for treating this pathology has been identified in the literature. Therefore, we aim to develop a low-cost simulator for training hemorrhoidal rubber ligation.

Methods The model was constructed using PVC pipe wrapped in neoprene fabric. Hemorrhoidal nipples and the pectineal line were also simulated using fabric and sewing threads. The procedure is performed with conventional anoscope and ligature forceps.

Conclusion The device in question is a low-cost simulation model designed to train the skills required to perform a rubber band ligation and review the basic anatomy of the anal canal during anoscopy. Given these qualities, the model can be used for academic training due to its low cost and simplicity of application.
Hip Valgus Osteotomy in Presence of Ipsilateral Femoral Retrograde Nail: A Case Study and Literature Review
Authors: Mahmoud Ahmed Nageeb , Echeverry-Martinez Maria F. , Horwitz Daniel S
Published: November 2023

Hip valgus osteotomy for femoral neck nonunion is a widely popular procedure with high success rates. In the setting of multiply injured patients, with concomitant femoral neck and shaft fractures, a potentially higher incidence of femoral neck nonunion rates may call for a hip valgus osteotomy in the presence of an existing retrograde intramedullary nail, which has not been reported in literature. We revisit the preoperative planning and describe the surgical technique of hip valgus osteotomy in a case of a nonunion of a femoral neck fracture after previous fixation of concomitant femoral shaft and femoral neck fractures using retrograde femoral nail and dynamic hip screw, respectively. Hip valgus osteotomy can be done proximal to a preexisting retrograde femoral nail with careful planning, without limiting the surgical technique or affecting the clinical outcomes, and when using combined fixation for neck shaft fractures certain technical features must be considered.
Exploring learning outcomes, communication, anxiety, and motivation in learning communities: a systematic review
Authors: Cao Wenwen , Yu Zhonggen
Published: November 2023

Learning communities have become a focal point of research due to their potential impact on learning outcomes, motivation, and communication. These factors are recognized as crucial determinants of the effectiveness of learning communities. To guide this study, a thorough review of 35 relevant studies was conducted, employing rigorous inclusion and exclusion criteria based on the PRISMA framework to ensure a systematic and robust approach. The findings of this study indicated that learning communities possess the capacity to enhance communication, motivation, and learning outcomes, while simultaneously alleviating learner anxiety. Specifically, it was observed that well-designed online learning communities can significantly improve learning outcomes. Furthermore, the utilization of online technologies within these communities can facilitate enhanced communication, leading to improved learning outcomes. Moreover, this study offers a range of recommendations for optimizing learning outcomes through the implementation of learning communities. These recommendations serve as valuable guidance for harnessing the full potential of learning communities to achieve educational goals. In conclusion, this study underscores the importance of learning communities in enhancing learning outcomes, motivation, and communication. It highlights the efficacy of appropriately designed online communities and the integration of technology in fostering effective communication and improving learning outcomes. The study contributes important insights into ways of maximizing the benefits of learning communities in promoting educational success.
The impact of automation and optimization on customer experience: a consumer perspective
Authors: Gavrila Gavrila Sorin , Blanco González-Tejero Cristina , Gómez Gandía José Andrés , de Lucas Ancillo Antonio
Published: November 2023

The adoption of digital technologies has significantly transformed businesses and society as a whole. The automation of tasks is leading to changes in organizational structures and strategies. Due to technological growth, users are able to identify the benefits and risks that technology can entail in the purchasing process. Specifically, robotic process automation (RPA) can improve efficiency and agility in a company, which in turn can positively impact consumer satisfaction and engagement. However, automation can also negatively affect the consumer experience and service quality if not applied correctly. Therefore, this research focuses on analyzing the impact of automation technologies on purchasing processes and consumer satisfaction. For this purpose, a survey was developed by means of the Likert 5-point scale, which allowed for obtaining 215 valid responses from consumers in the Community of Madrid. The data were processed through the SPSS tool, which enabled the analysis of the data and the proposed model. Consequently, the results show that potential RPA-based automation and optimization of processes can be of great utility for businesses to better address investment for improving consumer satisfaction. In addition, it should be highlighted that this research contributes in an original way to the area of information and communication technologies by allowing for the development of proactive technological implementation plans that consider end-user satisfaction.
EU countries’ digital transformation, economic performance, and sustainability analysis
Authors: Bocean Claudiu George , Vărzaru Anca Antoaneta
Published: November 2023

Digital transformation generates challenges and opportunities at the individual and organizational levels. Implementing digital technologies impacts all countries’ economic growth and orientation toward sustainability. This paper aims to evaluate the effects of digital transformation on the economic performance and sustainability of European Union (EU) countries. The paper employs artificial neural network analysis, structural equation modeling, and cluster analysis to investigate the relationships among digital transformation, economic performance, and sustainability. Economic performance is measured using GDP per capita, while SDG scores represent sustainability. The use of computers and the Internet in enterprises, the volume of e-commerce, and the percentages of implementing new digital technologies, such as cloud computing, Big Data, and the Internet of Things, illustrate digital transformation. The research findings reveal the extent of digital transformation in each country and the significant influence of digital transformation on economic performance and sustainability. The main drivers of digital transformation are the use of computers and the Internet in enterprises and e-commerce. However, new digital technologies exert increasingly noticeable effects, particularly in developed European countries. This study elucidates the profound implications of digital transformation on economic performance and sustainability. It underscores the pivotal role of digital technologies, especially in advanced European countries, in driving economic growth and sustainability. The results can be helpful to regulators in developing digitization strategies that underpin sustainable economic performance.
Laboratory investigation of nominally two-dimensional anabatic flow on symmetric double slopes
Authors: Goldshmid Roni H. , Liberzon Dan
Published: November 2023

We investigated the dynamics of highly turbulent thermally driven anabatic (upslope) flow on a physical model inside a large water tank using particle image velocimetry (PIV) and a thermocouple grid. The results showed that the flow exhibited pronounced variations in velocity and temperature and, importantly, could not be accurately modeled as a two-dimensional quasi-steady flow. Five significant findings are presented to underscore the three-dimensional nature of the flow, namely, the B-shaped mean velocity profiles, B-shaped turbulent flux profiles, synthetic streaks that revealed particles flowing perpendicular to the laser sheet, average vorticity maps revealing helical structure splitting, and identified vortices shooting away from the boundary toward the apex plume. Collectively, these findings offer novel insights into the flow behavior patterns of thermally driven complex terrain flows, which influence local weather and microclimates and are responsible for scalar transport, e.g., pollution.
Nonlinear trajectory estimation using extended state-space recursive least squares
Authors: Abid Anam
Published: November 2023

In a variety of filtering applications including target tracking, global positioning systems, and autonomous robots, the nonlinear nature of the system model makes estimation tasks challenging. This study presents an extended state-space recursive least squares (ESSRLS) filter for nonlinear trajectory estimation. The paper focuses on ESSRLS filter derivation for non-autonomous systems and investigates its performance against the extended Kalman filter and unscented Kalman filter for maneuvering aircraft trajectory estimation applications. The major accomplishment of the proposed approach is nonlinear filtering, independent of a priori information about noise statistics and the provision of the tuning parameter (forgetting factor). This makes the ESSRLS a more suited candidate for practical nonlinear filtering applications. The simulation results show that in the presence of model uncertainties, data outages (occlusion), and large initial condition deviations, the proposed method gives superior estimation performance as compared to the state-of-the-art.
Optical Kerr nonlinearity of dielectric nanohole array metasurfaces with different hole shapes near the anapole state
Authors: Panov Andrey V.
Published: November 2023

At present, optical anapole resonances in nanostructures have attracted increasing attention due to the strong field confinement and substantially suppressed scattering. This study provides the results of three-dimensional finite-difference time-domain simulations exhibiting the possibility of the anapole state in high refractive index dielectric nanohole array metasurfaces having different profiles of the holes (square, hexagon, and octagon). Behavior of the effective optical Kerr nonlinearity of the metasurfaces in the vicinity of the anapole state is investigated. Depending on the geometry, the absolute value of the effective nonlinear Kerr coefficient of the metasurface may be up to three orders of magnitude greater than that of the unstructured film. A square transverse section of the nanohole is preferable for the optical Kerr effect in the holey metasurfaces. The effect of the random rotation of the square holes representing the metasurface irregularity on the optical nonlinearity is examined. As a result, the dielectric nanohole array metasurfaces display a concrete possibility to have the anapole state with large enhancement of the optical nonlinearity.
Non-Oberbeck–Boussinesq effects on a water-filled differentially heated vertical cavity
Authors: Pan Xiaomin , Choi Jung-Il
Published: November 2023

In this study, we examined non-Oberbeck–Boussinesq (NOB) effects on a water-filled differentially heated vertical cavity through two-dimensional direct numerical simulations. The simulations encompassed a Rayleigh number (Ra) span of 107–1010, temperature difference (Δθ̃) up to 60 K, and a Prandtl number (Pr) fixed at 4.4. The center temperature (θcen) was found to be independent of Ra and to increase linearly with Δθ̃, as presented by θcen≈1.18×10−3 K−1Δθ̃. The thermal boundary layer (BL) thicknesses near the hot and cold walls (λ¯hθ and λ¯cθ, respectively) are found to scale as λ¯h,cθ∼Raγ λ¯h,c, where the scaling exponent γ λ¯h,c ranges from −0.264 to −0.262. For more detail, the scaling exponent γ λ¯h displays an increasing trend, while γ λ¯c demonstrates a decreasing trend. However, the sum of the hot and cold thermal BL thicknesses was found to be constant at a fixed Ra in the presence of NOB effects. Our detailed investigation of the Nusselt number (Nu) and Reynolds number (Re) revealed that Nu∼Ra0.258 and Re∼Ra0.364, showing insensitivity to NOB effects. These exponents were smaller than those for Rayleigh–Bénard convection. The NOB modifications on Nu and Re were less than 1.2% and 2.5%, respectively, even at Δθ̃=60 K. Our results also revealed that key parameters such as θcen and normalized ratios [(λ¯NOBθ/λ¯OBθ)h,c, NuNOB/NuOB, and ReNOB/ReOB] exhibit universal correlations with Δθ̃. Remarkably, these relationships are consistent across varying Ra values. This observation underscored the influence of NOB effects on these parameters could be confidently forecasted using just the temperature difference (Δθ̃) for Ra∈[107,1010].
Limits of Ohm’s law in ultra-pure metals with almost ideal crystal lattices
Authors: Elefant Dieter
Published: November 2023

By electric transport measurements on high-purity bulk molybdenum single crystals at helium-temperature, it is shown that when approaching the ideal metallic crystal structure, there are deviations from Ohm’s law that can exceed 30% even at low current densities ≅3A/mm2. This is due to the intrinsic circular magnetic field of the measuring current in the range of B≅1mT, which generates a magnetoresistance according to the two-band conduction model. With increasing lattice vibrations and/or crystal defects, this inherent uncertainty finally reduces to immeasurably small values. Finally, Ohm’s law for a nearly ideal lattice structure can be strictly exact only in the theoretical limiting case of an infinite lattice plane, because then the magnetic fields of all electrons of the current compensate to zero.
Quantitative x ray phase contrast imaging of oblique shock wave–interface interactions
Authors: Leong Andrew F. T. , Romick Christopher M. , Bolme Cynthia A. , Aslam Tariq D. , Sinclair Nicholas W. , Kozlowski Pawel M. , Montgomery David S. , Ramos Kyle J.
Published: November 2023

Oblique shock wave–interface interactions of gases and liquids have been extensively studied in shock tubes using optical methods to measure equation-of-state (EOS) parameters. However, this is difficult with solids due to their opaqueness to visible light. X ray phase contrast imaging (XPCI) has the penetrative strength to probe solids while still being sensitive to mass density and enhancing the visibility of material boundaries. We investigate the accuracy and repeatability of measuring the mean value of the average mass density (areal density divided by thickness) over region S (BS) and flow deflection angle (θ) from XPCI images of a sample. To that end, a Hough transform-based method for measuring θ is developed. To measure BS, the XPCI image intensity probability density function (PDF) is modeled accounting for the spatial distribution of x ray energy, scintillator response, and pulse-to-pulse variation in the x ray intensity. In addition, a Monte Carlo-based algorithm for computing the BS PDF is developed. Both methods are validated on an impact-generated oblique shock wave interacting at a solid polymer-to-polymer interface. This is accomplished through a comparison to hydrodynamic simulations using well-established EOS. Under the modeling framework for the XPCI image intensity, BS is computed with an accuracy of <0.1% and precision of 3%–5%, while θ has an uncertainty of 0.2°, respectively. This shows that the XPCI-based model that is developed here could be an invaluable tool for high-fidelity testing of hydrodynamic models in shock polar configurations.
Dynamics of displacement flows of viscoplastic fluids in obstructed eccentric annuli at moderate Reynolds numbers
Authors: Mitishita Rodrigo S. , Alishahi Marzieh , Frigaard Ian A.
Published: November 2023

As a sequel to Mitishita et al. [“Turbulent displacement flows of viscoplastic fluids in obstructed eccentric annuli: Experiments,” Phys. Fluids 34, 053114 (2022)], we present an experimental study of laminar displacement flows in obstructed eccentric annuli. Xanthan gum (XG) solutions (0.35%, 0.50%, or 0.75%) are used to displace a 0.15% viscoplastic Carbopol solution. The eccentricity of the annulus section is set to near 0.5. We study the effect of a solid obstruction in the narrow side of the annulus, similar to that provided by a consolidated residual cuttings bed, and compare the results to unobstructed displacement flows. While we predicted that all displacements would be in the laminar regime, we actually observe mixed regimes where the initial displacement of Carbopol can be transitional or turbulent. With the obstruction on the narrow side of the annulus, we observe the formation of cavities in the Carbopol layer, both upstream and downstream of the obstruction. We believe that the cavities are formed because the obstruction behaves like an abrupt contraction/expansion. This geometric irregularity affects the velocity profiles of the displacing fluid near the obstruction. Once the cavities reach the bottom of the pipe, we observe that the remaining Carbopol layer is more easily eroded. The dynamics of the Carbopol removal also share similarities to cleaning of soil layers in pipes, as described by Palabiyik et al. [“Flow regimes in the emptying of pipes filled with a Herschel–Bulkley fluid,” Chem. Eng. Res. Des. 92, 2201–2212 (2014)].
Ion acceleration in expanding plasma in small radio frequency plasma thruster with a magnetic cusp
Authors: Furukawa Takeru , Aoyagi Hiroto , Oshio Yuya , Nishida Hiroyuki
Published: November 2023

Ambipolar electric field is formed in the expanding plasma of the small radio frequency plasma thruster using a cusp-shaped magnetic field. A highly energized group of ion energy distribution function is observed in the z-direction, indicating the presence of axial ion acceleration downstream the magnetic nozzle owing to the electric field. The mean velocity profile of the beam ions along the z axis is evaluated using the energy distribution functions along the z axis. The high axial ion velocity profile stretches downstream, although the evaluated dimensionless velocity profile is lower than that calculated using quasi-one-dimensional models. It is suggested that ion momentum loss can result from ion-neutral collision, leading to beam divergence in the magnetic nozzle of the proposed small thruster.
Numerical study on vortex-induced vibration of four circular cylinders at low Reynolds number
Authors: Han Yanqing , Zhai Tianyu , Zhang Yunxing , Zhang Yifan
Published: November 2023

Vortex-Induced Vibration (VIV) of multiple cylinders has received increasing attention in the ocean engineering field in recent years. In this paper, a two-dimensional numerical model for studying VIV of multiple cylinders is developed. Based on a fixed Cartesian grid with local mesh refinement adopted, the immersed boundary method is utilized to account for the existence of cylinders. Two-degree-of-freedom VIV of a single circular cylinder is simulated to validate the model, and then the model is utilized in the VIV of a four circular-cylinder group with square arrangement. The mass ratio is m* = 2.0, and the spacing ratio L/D is 5.0, where L is the central displacement of two adjacent cylinders and D is the diameter of the cylinders. Reynolds number ranging from 45 to 210 is considered, and the variation of which is achieved by changing the inflow velocity. The corresponding reduced velocity varies from 3 to 14. The influences of Reynolds number on the vibrating frequencies, the response amplitudes, the X–Y trajectories, the vorticity field distribution, and the hydrodynamic coefficients are analyzed in detail. A critical Reynolds number of 105 is observed, at which the X–Y trajectories and the vorticity field distribution change their patterns.
Is chemical vapor deposition of monolayer WSe2 comparable to other synthetic routes?
Authors: Choi Soo Ho , Yang Sang-Hyeok , Park Sehwan , Cho Byeong Wook , Nguyen Tuan Dung , Kim Jung Ho , Kim Young-Min , Kim Ki Kang , Lee Young Hee
Published: November 2023

Chemical vapor deposition (CVD) can produce wafer-scale transition-metal dichalcogenide (TMD) monolayers for the integration of electronic and optoelectronic devices. Nonetheless, the material quality of the CVD-grown TMDs still remains controversial. Here, we compare the quality of representative WSe2 monolayers grown by CVD compared to that obtained by other synthesis methods: bulk-grown-chemical vapor transport (CVT) and flux. Through the use of a deep-learning–based algorithm to analyze atomic-resolution scanning transmission electron microscopy images, we confirm that Se vacancies (VSe) are the primary defects in WSe2, with a defect density of ∼5.3 × 1013 cm−2 in the CVD-grown sample, within the same order of magnitude of other methods (∼3.9 × 1013 cm−2 from CVT-grown samples and ∼2.7 × 1013 cm−2 from flux-grown samples). The carrier concentration in field-effect transistors at room temperature is ∼5.84 × 1012 cm−2 from a CVD-grown sample, comparable to other methods (6–7 × 1012 cm−2). The field-effect mobility of the CVD-grown sample is slightly lower than that of other synthesis methods, together with similar trends in on-current. While the difference in photoluminescence intensity is not appreciable at room temperature, different intensities of defect-related localized states appear below 60 K. We conclude that the wafer-scale CVD-grown samples can be utilized without loss of generality in the integration of electronic/optoelectronic devices.
Spectroscopy of C60+ and C120+ in the mid-infrared
Authors: Kappe Miriam , Schiller Arne , Gruber Elisabeth , Jank Dominik , Gatt Michael , Schöpfer Gabriel , Ončák Milan , Ellis Andrew M. , Scheier Paul
Published: November 2023

Infrared spectra of C60+ and C120+, obtained via helium messenger spectroscopy, are reported. For C60+, new absorption features have been found just above the discrete vibrational spectrum of the ion. The absorption profile, which is broad and contains little structure, is assigned to one or more electronic absorption transitions and is in good agreement with predictions from time-dependent density functional theory. It seems likely that the transitions observed correspond to excitation from the 2A1u electronic ground state to one or both of the low-lying 2E1u and 2E2u electronic states previously identified as dark states of C60+. These states presumably become optically bright through vibronic coupling and specifically the Jahn–Teller effect. In the case of C120+, the simplest positively charged oligomer of C60, we present the first vibrational spectrum of this ion. Through a comparison with theory, vibrational features are best explained by a peanut-shaped structure for C120+, maintained by covalent bonding between the two C60 units. We have also discovered electronic transitions for C120+, which, similar to C60+, lie just above the vibrational spectrum.
Mn impurity band and the effects of Mn position in III–V lattice: Pivotal contributions of Władek Walukiewicz to the understanding of ferromagnetism in semiconductors
Authors: Furdyna Jacek K. , Liu Xinyu , Dobrowolska Małgorzata , Lee Sanghoon
Published: November 2023

This paper describes the contributions made by Władysław (Władek) Walukiewicz and his colleagues to the field of ferromagnetic semiconductor (FMS) alloys, such as (Ga,Mn)As. We focus on two key accomplishments. First, this team has predicted the formation of Mn interstitials in these materials, which have a profound effect on ferromagnetism in semiconductors. Additionally, identifying the conditions at which interstitials form has provided grounds for optimizing their ferromagnetic properties. Second, by applying the approach of band anticrossing to ferromagnetic semiconductors, this team has mapped out the properties of an Mn-derived impurity band in these materials. This is of particular importance in the field, because holes, which reside in the Mn-derived impurity band, are the very mechanism responsible for ferromagnetic order in FMSs. We discuss the effect that these accomplishments have on our understanding of FMSs and how they have contributed to progress in this area. We then describe the pathways that these achievements have opened up toward further progress in both basic and applied fronts of ferromagnetism in semiconducting systems; and we present our perspective on where additional work along the lines initiated by Władek Walukiewicz should be extended to further benefit this field.
Resonant interactions involving local vibrational modes in crystals
Authors: McCluskey Matthew D.
Published: November 2023

When an impurity with a light mass is inserted into a crystal, it can undergo a high-frequency oscillation referred to as a local vibrational mode (LVM). A Fermi resonance may occur between the LVM and lower-frequency modes of the defect. The LVM may also interact with phonons or the electromagnetic field. Understanding these interactions can help model and control diffusion, defect reactions, and thermal conductivity. LVMs have been probed in semiconductors using pressure and alloying as experimental parameters, resulting in anticrossing between localized and extended vibrational modes. These types of vibrational interactions could play an important role in the stability and thermal properties of organic–inorganic hybrid semiconductors. The coupling between an LVM and electromagnetic wave yields an “LVM polariton,” an excitation that has significant vibrational and electric-field amplitudes.
Optical spectroscopy of the previously unobserved palladium monosulfide (PdS) radical
Authors: Zhang Lei , Zou Wenli , Yu Yao , Yang Jie
Published: November 2023

The optical spectra of the palladium monosulfide (PdS) molecule in gas phase have been investigated for the first time through laser-induced fluorescence (LIF) and single-vibronic-level (SVL) emission spectroscopies. The I3Σ− − X3Σ− transition system containing 16 vibronic bands was identified in the LIF spectra, covering the energy range of 22 030–23 400 cm−1. The spectra with rotational resolution allowed for the determination of the molecular constants in both the ground X and excited I electronic states, involving the spin–orbit splitting, rotational constant, vibrational frequency, and isotope shift. Isotopically resolved SVL emission spectra permitted the observation of the spin–orbit splitting, vibrational frequency, and vibrational isotope shift of the X3Σ−0+,1 and A3Π2,1,0−,0+ states as they transitioned from the excited I state to the vibrational levels of the X and A states. Ab initio calculations presented plenty of the Λ-S and Ω states of PdS below 28 000 cm−1 and provided strong support for the assignments of the experimental observation.
Review of Scientific Instruments New Products
Authors: Mandelis Andreas
Published: November 2023

In order to supplement manufacturers’ information, this department will welcome the submission by our readers of brief communications reporting measurements on the physical properties of materials, which supersede earlier data or suggest new research applications.
Both long-term grasslands and crop diversity are needed to limit pest and weed infestations in agricultural landscapes
Authors: Perrot Thomas , Rusch Adrien , Gaba Sabrina , Bretagnolle Vincent
Published: November 2023

Increasing landscape heterogeneity has been suggested to be an important strategy to strengthen natural pest control in crops, especially through enhancing the amount of seminatural habitats. Increasing crop diversity is also a promising strategy to complement or replace seminatural habitat when seminatural habitat is scarce. However, their relative or possibly interactive effects on pest and weed infestation remain poorly investigated, and the role of different types of seminatural habitats has been understudied. Using an extensive sampling effort in 974 arable fields across 7 y, we evaluated the separate and interactive effects of crop diversity (seven arable crop types) and the amount of four types of seminatural habitats (meadows, hay, forests, and hedgerows) in the landscape on pest and weed control. Meadows and crop diversity, respectively, supported insect pest and weed control services in agricultural landscapes through a complementarity effect. Crop diversity increased weed seed predation rate (by 16%) and reduced weed infestation (by 6%), whereas long-term grasslands (to a much higher degree than hay or woody habitats) increased insect pest predation rates (by 23%) and reduced pest infestation (by 19%) in most arable crops. Our results demonstrate that diversification of the agricultural landscape requires long-term grasslands as well as improved crop diversity to ensure the delivery of efficient pest and weed control services.
Gene expression in the primate orbitofrontal cortex related to anxious temperament
Authors: Kenwood Margaux M. , Souaiaia Tade , Kovner Rothem , Fox Andrew S. , French Delores A. , Oler Jonathan A. , Roseboom Patrick H. , Riedel Marissa K. , Mueller Sascha A. L. , Kalin Ned H.
Published: November 2023

Anxiety disorders are among the most prevalent psychiatric disorders, causing significant suffering and disability. Relative to other psychiatric disorders, anxiety disorders tend to emerge early in life, supporting the importance of developmental mechanisms in their emergence and maintenance. Behavioral inhibition (BI) is a temperament that emerges early in life and, when stable and extreme, is linked to an increased risk for the later development of anxiety disorders and other stress-related psychopathology. Understanding the neural systems and molecular mechanisms underlying this dispositional risk could provide insight into treatment targets for anxiety disorders. Nonhuman primates (NHPs) have an anxiety-related temperament, called anxious temperament (AT), that is remarkably similar to BI in humans, facilitating the design of highly translational models for studying the early risk for stress-related psychopathology. Because of the recent evolutionary divergence between humans and NHPs, many of the anxiety-related brain regions that contribute to psychopathology are highly similar in terms of their structure and function, particularly with respect to the prefrontal cortex. The orbitofrontal cortex plays a critical role in the flexible encoding and regulation of threat responses, in part through connections with subcortical structures like the amygdala. Here, we explore individual differences in the transcriptional profile of cells within the region, using laser capture microdissection and single nuclear sequencing, providing insight into the molecules underlying individual differences in AT-related function of the pOFC, with a particular focus on previously implicated cellular systems, including neurotrophins and glucocorticoid signaling.
SPA, a Stigma-style-transmitting tract Physical microenvironment Assay for investigating mechano-signaling in pollen tubes
Authors: Zhou Xiang , Han Wenbo , Dai Jiawei , Liu Sujuan , Gao Shiyuan , Guo Yi , Xu Tiegang , Zhu Xiaoyue
Published: November 2023

Accurate sensing and responding to physical microenvironment are crucial for cell function and survival, but the underlying molecular mechanisms remain elusive. Pollen tube (PT) provides a perfect single-cell model for studying mechanobiology since it’s naturally subjected to complex mechanical instructions from the pistil during invasive growth. Recent reports have revealed discrepant PT behaviors between in vivo and flat, two-dimensional in vitro cultures. Here, we established the Stigma-style-transmitting tract (TT) Physical microenvironment Assay (SPA) to recapitulate pressure changes in the pistil. This biomimetic assay has enabled us to swiftly identify highly redundant genes,
GEF8/9/11/12/13,
as new regulators for maintaining PTs integrity during style-to-TT emergence. In contrast to normal growth on solid medium, SPA successfully phenocopied
gef8/9/11/12/13
PT in vivo growth-arrest deficiency. Our results suggest the existence of distinct signaling pathways regulating in vivo and in vitro PT integrity maintenance, underscoring the necessity of faithfully mimicking the physical microenvironment for studying plant cell biology.
Peripheral blood TCR clonotype diversity as an age-associated marker of breast cancer progression
Authors: Nishida Jun , Cristea Simona , Bodapati Sudheshna , Puleo Julieann , Bai Gali , Patel Ashka , Hughes Melissa , Snow Craig , Borges Virginia , Ruddy Kathryn J. , Collins Laura C. , Feeney Anne-Marie , Slowik Kara , Bossuyt Veerle , Dillon Deborah , Lin Nancy U. , Partridge Ann H. , Michor Franziska , Polyak Kornelia
Published: November 2023

Immune escape is a prerequisite for tumor growth. We previously described a decline in intratumor activated cytotoxic T cells and T cell receptor (TCR) clonotype diversity in invasive breast carcinomas compared to ductal carcinoma in situ (DCIS), implying a central role of decreasing T cell responses in tumor progression. To determine potential associations between peripheral immunity and breast tumor progression, here, we assessed the peripheral blood TCR clonotype of 485 breast cancer patients diagnosed with either DCIS or de novo stage IV disease at younger (<45) or older (≥45) age. TCR clonotype diversity was significantly lower in older compared to younger breast cancer patients regardless of tumor stage at diagnosis. In the younger age group, TCR-α clonotype diversity was lower in patients diagnosed with de novo stage IV breast cancer compared to those diagnosed with DCIS. In the older age group, DCIS patients with higher TCR-α clonotype diversity were more likely to have a recurrence compared to those with lower diversity. Whole blood transcriptome profiles were distinct depending on the TCR-α Chao1 diversity score. There were more CD8
+
T cells and a more active immune environment in DCIS tumors of young patients with higher peripheral blood TCR-α Chao1 diversity than in those with lower diversity. These results provide insights into the role that host immunity plays in breast cancer development across different age groups.
Tourism Clusters, Nature Research and Visitor Experiences: The Case of Fundación Batis in Barranquilla, Colombian Caribbean
Authors: Solano Beatriz-Helena Díaz , Gardella Narcís Bassols i
Published: November 2023

Clusters are beneficial to tourist companies in a number of ways as they have been found to promote innovation of both product and market. The case of Fundación Batis, located in the Colombian Caribbean, will be examined as a best practice in terms of adding tourism to a company’s supply to achieve diversification and supplemental revenue. After a successful incubation in a cluster, this foundation opened its doors to tourists, and its employees now engage in an open dialogue with visitors about conservation issues. As a result, the region gains an upscale offer in natural tourism, which helps to upgrade and diversify the local tourism product.

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© The Authors 2023
Dark energy, D-branes and pulsar timing arrays
Authors: Chowdhury Debika , Tasinato Gianmassimo , Zavala Ivonne
Published: November 2023

Several pulsar timing array (PTA)
collaborations recently announced the first
detection of a stochastic
gravitational wave (GW) background, leaving open the question of its source.
We explore the possibility that it originates from cosmic inflation, a guaranteed
source of primordial GW. The inflationary GW background
amplitude is enhanced at PTA scales by a non-standard
early cosmological evolution, driven by Dirac-Born-Infeld (DBI) scalar
dynamics motivated by string theory. The resulting
GW energy density has a broken power-law frequency profile, entering
the PTA band with
a peak amplitude consistent with the recent GW detection.
After this initial DBI kination epoch, the dynamics starts a new phase
mainly controlled by the scalar potential. It provides a realization of an early dark energy scenario aimed
at relaxing the H
0 tension, and a late dark energy model which explains
the current cosmological acceleration with no need of a cosmological constant.
Hence
our mechanism — besides
providing a possible explanation for the recent PTA results —
connects them with testable properties of the physics of the dark universe.
Electronic property and topological phase transition in a graphene/CoBr2 heterostructure
Authors: Qin 秦 Yuan-Xiu 元秀 , Li 李 Sheng-Shi 胜世 , Ji 纪 Wei-Xiao 维霄 , Zhang 张 Chang-Wen 昌文
Published: November 2023

Recently, significant experimental advancements in achieving topological phases have been reported in van der Waals (vdW) heterostructures involving graphene. Here, using first-principles calculations, we investigate graphene/CoBr2 (Gr/CoBr2) heterostructures and find that an enhancement of in-plane magnetic anisotropy (IMA) energy in monolayer CoBr2 can be accomplished by reducing the interlayer distance of the vdW heterostructures. In addition, we clarify that the enhancement of IMA energy primarily results from two factors: one is the weakness of the Co-d
xy
and Co-d
x
2–y
2
orbital hybridization and the other is the augmentation of the Co-d
yz
and Co-d
z
2
orbital hybridization. Meanwhile, calculation results suggest that the Kosterlitz–Thouless phase transition temperature (T
KT) of a 2D XY magnet Gr/CoBr2 (23.8 K) is higher than that of a 2D XY monolayer CoBr2 (1.35 K). By decreasing the interlayer distances, the proximity effect is more pronounced and band splitting appears. Moreover, by taking into account spin–orbit coupling, a band gap of approximately 14.3 meV and the quantum anomalous Hall effect (QAHE) are attained by decreasing the interlayer distance by 1.0 Å. Inspired by the above conclusions, we design a topological field transistor device model. Our results support that the vdW interlayer distance can be used to modulate the IMA energy and QAHE of materials, providing a pathway for the development of new low-power spintronic devices.