bluuebunny/crossref_metadata_2025 huggingface dataset:
Overview of WiFi fingerprinting‐based indoor positioning
Authors: Shang Shuang , Wang Lixing
Published: April 2022

Location‐based services have attracted significant attention since the concept of Industry 4.0 was proposed and the ‘Internet +’ era began owing to its social and commercial value. Many scholars have attempted to introduce machine learning in indoor fingerprint positioning to improve indoor positioning accuracy, enhance system robustness, reduce costs, and improve the performance of indoor positioning methods. A comprehensive overview of indoor positioning technology, its methods, and classifications is provided. Furthermore, a detailed review of the application of WiFi fingerprinting and machine learning methods in indoor positioning is presented, and the advantages and disadvantages of these methods when applied to indoor positioning are analyzed. This study summarizes the difficulties and challenges encountered by indoor positioning and suggests development directions.
Robust service provisioning of service function chain under demand uncertainty
Authors: Qiu Hang , Tang Hongbo , You Wei , Xu Mingyan , Wang Kai
Published: April 2022

In network function virtualization, resource allocation is one of the key techniques to ensure the QoS of service requests in face of the uncertain traffic demand and traffic fluctuation of user services. The previous related works usually assume that the traffic demand is a deterministic value and then reallocate substrate resources to deal with the demand uncertainty and traffic fluctuation during operation. In response to performance degradation caused by demand uncertainty and traffic fluctuation, the paper models the service function chain orchestration under demand uncertainty as a robust optimization problem, where the parameter Γ is introduced to control the conservativeness of the solution. On this basis, the strong duality theory is used to transform the original problem into a mixed‐integer linear programming, and then devise an exact Robust Service Provisioning (RSP) algorithm. The simulation evaluation demonstrates that the proposed algorithm could achieve different levels of robustness and make a trade‐off between robustness and cost. The impact of Γ value on the realized robustness and price of robustness is also analysed. Thus, the algorithm proposed could get an effective service function chain orchestration scheme under uncertain traffic demands and provide a reference of the total cost.
Partial and statistical CSI based precoding for reduced‐CP OTFS with inter‐slot‐interference pre‐cancellation
Authors: Zhang Yuan , Du Peng , Wang Jiang
Published: April 2022

This work studies the precoding methods for the reduced cycle‐prefix (CP) orthogonal time frequency space (OTFS) modulation to simplify the receiver design. First, a system model is established which shows that there are both intra‐slot‐interference and inter‐slot‐interference in the reduced‐CP OTFS system. Then, the precoding operation is proposed to pre‐cancel the inter‐slot‐interference in the reduced‐CP OTFS system so that the bit error rate (BER) performance can be greatly improved. According to how much channel state information (CSI) needs to be fed back, precoding methods for two different cases are proposed: the partial CSI feedback case and the partial and statistical CSI feedback case. Among them, the partial and statistical CSI based precoding method has very small feedback burden. Simulation results of the BER performance of the proposed precoding methods for reduced‐CP OTFS are reported and compared under different system parameters.
Multi‐application multi‐port DC–DC converter consisting six ports with four main operation modes
Authors: Mohammadi Tanha Kambiz , Abbasi Vahid , Mohammadi Kourosh
Published: April 2022

This paper proposes a multi‐port DC–DC converter consisting of three input ports and two output ports extendable to three. The converter is designed based on quadratic boost converter, a technique for bidirectional port, an auxiliary source and two output ports with opposite polarities. Designed method of the configuration makes it suitable for multi‐applications with flexible operations. Connection of the converter to a bipolar system is possible due to opposite polarities of output ports. In addition, output voltage can be doubled by series connection between the two out ports and it is introduced as the third output port of the converter. The other advantages of the converter are its appropriate voltage gain, performance in stand‐alone mode with storage port and possibility of boosting voltage with similar voltage gains in different operation modes. To validate feasibility of the converter and investigate coordination of its performance with theory, a prototype is prepared for 120 W output power.
Gesunde Schulkinder
Authors: Kupka-Klepsch Elisabeth
Published: April 2022

Schulgesundheitspflege ist in der DACH-Region in der Praxis nur wenig verbreitet. In Österreich ist sie seit der Novelle des Gesundheits- und Krankenpflegegesetzes in den Kernkompetenzen des gehobenen Dienstes für Gesundheits- und Krankenpflege verankert 1. Über die geltende Schulpflicht können, wie über kaum einen anderen Zugang, alle Kinder eines Landes erreicht werden. Die vorliegende Forschungsarbeit zeigt Dimensionen wirkungsvoller Gesundheitsförderung in Grundschulen und mögliche Aufgabenbereiche von School Health Nurses auf.
Administration of Orexin-A into the Rat Thalamic Paraventricular
Nucleus Enhances the Naloxone Induced Morphine Withdrawal
Authors: Babaie Fatemeh , Kourosh-Arami Masoumeh , Farhadi Mona
Published: April 2022

Objective Orexin neuropeptides are implicated in physical dependence on
opioids and expression of withdrawal symptoms in drug abuse. The paraventricular
nucleus of the midline thalamus (PVT) has a high expression of orexin receptors.
The current research studied the effect of orexin-A in the PVT area on the
development of behavioral indices produced by morphine withdrawal in rats.

Methods Male Wistar rats weighing 250–300 gr were utilised. To
produce drug dependence, morphine (6, 16, 26, 36, 46, 56, and
66 mg/kg, 2 ml/kg) was injected at an interval
of 24 hrs for 7 days. To assess the involvement of the orexin in withdrawal
syndrome, we injected orexin-A (100 μM, 200 nl) into the
PVT for 7 days before each morphine injection. On the day after the last
injection of morphine, naloxone (2.5 mg/kg, i.p.) was injected
to elicit the morphine withdrawal symptoms which were observed and checked for
25 min.

Results The results of the current research showed that the orexin-A in
PVT enhances the severity of behavioral symptoms prompted by the injection of
naloxone in drug-dependent rats.

Conclusions These observations imply that targeting the orexin receptors
in PVT might exhibit a new therapeutic strategy for the future treatment of
dependence.
Lessons Learnt from an 11-year Experience with Lymphatic Surgery and a Systematic Review of Reported Complications: Technical Considerations to Reduce Morbidity
Authors: Ciudad Pedro , Escandón Joseph M. , Manrique Oscar J. , Bustos Valeria P.
Published: April 2022

Complications experienced during lymphatic surgery have not been ubiquitously reported, and little has been described regarding how to prevent them. We present a review of complications reported during the surgical management of lymphedema and our experience with technical considerations to reduce morbidity from lymphatic surgery. A comprehensive search across different databases was conducted through November 2020. Based on the complications identified, we discussed the best approach for reducing the incidence of complications during lymphatic surgery based on our experience. The most common complications reported following lymphovenous anastomosis were re-exploration of the anastomosis, venous reflux, and surgical site infection. The most common complications using groin vascularized lymph node transfer (VLNT), submental VLNT, lateral thoracic VLNT, and supraclavicular VLNT included delayed wound healing, seroma and hematoma formation, lymphatic fluid leakage, iatrogenic lymphedema, soft-tissue infection, venous congestion, marginal nerve pseudoparalysis, and partial flap loss. Regarding intra-abdominal lymph node flaps, incisional hernia, hematoma, lymphatic fluid leakage, and postoperative ileus were commonly reported. Following suction-assisted lipectomy, significant blood loss and transient paresthesia were frequently reported. The reported complications of excisional procedures included soft-tissue infections, seroma and hematoma formation, skin-graft loss, significant blood loss, and minor skin flap necrosis. Evidently, lymphedema continues to represent a challenging condition; however, thorough patient selection, compliance with physiotherapy, and an experienced surgeon with adequate understanding of the lymphatic system can help maximize the safety of lymphatic surgery.
Survey of Areas Underserved by Plastic Surgery in Japan
Authors: Sato Makoto
Published: April 2022

Background In Japan, there is a large regional disparity in plastic surgery availability. In order for plastic surgery to be widely available for all citizens, it is essential for at least one plastic surgery facility to be located in each secondary medical zone.

Methods Using the Japan Society of Plastic and Reconstructive Surgery homepage and some databases, we extracted data on secondary medical zones that do not have a plastic surgery facility. The national and regional coverage rates were calculated. The coverage rate for each group divided by the degree of population concentration was also calculated.

Results We found that 147 of 344 secondary medical zones did not have a plastic surgery facility, and the area coverage rate was found to be 57.27% nationwide. The coverage rate in terms of population was 87.07% (correlation coefficient of area and population coverage = 0.983). The area coverage rates in Hokkaido-Tohoku, Kanto, Chubu, Kansai, Chugoku-Shikoku, and Kyushu-Okinawa districts were 47.46, 72.15, 76.47, 62.79, 52.08, and 32.81%, respectively. The corresponding population coverage rates were 79.92, 91.62, 94.27, 90.59, 80.68, and 69.54%, respectively. The area coverage rates in metropolitan areas, provincial cities, and rural areas were 98.08, 75.90, and 15.87%, respectively. In contrast, the area coverage rate of dermatology was 62.79% and that of orthopaedics was 97.09%.

Conclusion Unfortunately, it is estimated that more than 40% of secondary medical zones are underserved by plastic surgery, and 13% of the population is not able to fully benefit from this specialty in Japan.
A study of factors affecting women’s lived experiences in STEM
Authors: Prieto-Rodriguez Elena , Sincock Kristina , Berretta Regina , Todd Juanita , Johnson Sarah , Blackmore Karen , Wanless Erica , Giacomini Anna , Gibson Lauren
Published: April 2022

The number of women employed in STEM in Australia is increasing, however, they continue to remain underrepresented in most industries. A significant corpus of literature on female underrepresentation has emerged in the past 20 years, however, many of those studies focus on educational access and retention and not many look at the lived experiences of women after they have left higher education. In this article, we take a different stance and explore the heterogeneous experiences of female STEM professionals in regional Australia. Through the qualitative analysis of 25 interviews, we learn what women have endured, accepted, and valued on their individual STEM journeys. While these journeys are often quite different, our interviewees independently reported having experienced similar societal prejudices and possessing similar personality traits. Our data reveals that resilience and determination proved vital for these women, as did a strong early interest in STEM. Our interviews also unearth issues in which women’s opinions are fiercely divided, such as whether positive discrimination has been a barrier or an enabler for their careers. Based on what we have learnt from their accounts, we argue that these women have ‘survived’ their work environments despite structural barriers, only due to their determination, resilience and fervent interest.
Dual-function flexible metasurface for absorption and polarization conversion and its application for radar cross section reduction
Authors: Fang Shuguang , Deng Lianwen , Zhang Pin , Qiu Leilei , Xie Haipeng , Huang Shengxiang , Du Junsa , Wang Zijian
Published: April 2022

In this paper, a flexible metasurface with dual functions of absorption and polarization conversion is proposed and applied for radar cross section (RCS) reduction. The metasurface unit adopts a metallic-backed structure, and its width and thickness are approximately 0.62 and 0.24 times the free-space wavelength at the center working frequency, respectively. Different from the traditional metasurface, the resonators with low-frequency absorption and high-frequency polarization conversion are horizontally combined to achieve dual-function integration without the use of tunable elements. The structure adopts a flexible substrate, which is also suitable for conformal conditions. From 3.74 to 14.84 GHz, the metasurface has good impedance matching characteristics. The metasurface performs effective absorption and polarization conversion in the frequency bands of 3.78–6.34 GHz and 7.90–14.80 GHz, respectively. The absorption is mainly achieved through the ohmic loss of the lumped resistance, while the polarization conversion is performed through the electromagnetic resonance of the metallic structure. Then, the sample prototype is fabricated for demonstration, and the measurement result is well consistent with the simulation one. Furthermore, the checkerboard-arrangement array of the metasurface and its mirror unit can efficiently reduce the RCS over 7 dB in the range of 3.52–15.28 GHz. As expected, the proposed flexible metasurface can not only be used as an absorber/polarization converter but also be combined to realize broadband RCS reduction, which is of great significance for multi-function and conformal stealth applications.
Model-assisted deep learning of rare extreme events from partial observations
Authors: Asch Anna , J. Brady Ethan , Gallardo Hugo , Hood John , Chu Bryan , Farazmand Mohammad
Published: April 2022

To predict rare extreme events using deep neural networks, one encounters the so-called small data problem because even long-term observations often contain few extreme events. Here, we investigate a model-assisted framework where the training data are obtained from numerical simulations, as opposed to observations, with adequate samples from extreme events. However, to ensure the trained networks are applicable in practice, the training is not performed on the full simulation data; instead, we only use a small subset of observable quantities, which can be measured in practice. We investigate the feasibility of this model-assisted framework on three different dynamical systems (Rössler attractor, FitzHugh–Nagumo model, and a turbulent fluid flow) and three different deep neural network architectures (feedforward, long short-term memory, and reservoir computing). In each case, we study the prediction accuracy, robustness to noise, reproducibility under repeated training, and sensitivity to the type of input data. In particular, we find long short-term memory networks to be most robust to noise and to yield relatively accurate predictions, while requiring minimal fine-tuning of the hyperparameters.
Observation of unsaturated platinum carbenes Pt2C2n− (n = 1–3) clusters: A photoelectron imaging spectroscopic and theoretical study
Authors: Liu Xuegang , Li Gang , Liu Zhiling , Zou Jinghan , Yang Dong , Du Shihu , Yang Wenshao , Jiang Ling , Xie Hua
Published: April 2022

The structural and bonding properties of the Pt2C2n− (n = 1–3) complexes have been investigated by mass-selected photoelectron velocity-map imaging spectroscopy with quantum chemical calculations. The adiabatic detachment energies and vertical detachment energies of Pt2C2n− have been obtained from the measured photoelectron imaging spectra. Theoretical results indicate that the lowest-energy isomers of Pt2C2n− (n = 1–3) possess linear chain-shaped configurations. The binding motif in the most stable isomer of Pt2C2− has a linear cumulenic structure with a Pt=C=C=Pt configuration, and the structural characteristic persists up to all the lowest-energy isomers of the Pt2C4− and Pt2C6− anions. The chemical bonding analyses indicate that the Pt2C2n− (n = 1–3) complexes have multicenter two-electron characteristics.
Electronic and mechanical anharmonicities in the vibrational spectra of the H-bonded, cryogenically cooled X− · HOCl (X=Cl, Br, I) complexes: Characterization of the strong anionic H-bond to an acidic OH group
Authors: Stropoli Santino J. , Khuu Thien , Boyer Mark A. , Karimova Natalia V. , Gavin-Hanner Coire F. , Mitra Sayoni , Lachowicz Anton L. , Yang Nan , Gerber R. Benny , McCoy Anne B. , Johnson Mark A.
Published: April 2022

We report vibrational spectra of the H2-tagged, cryogenically cooled X− · HOCl (X = Cl, Br, and I) ion–molecule complexes and analyze the resulting band patterns with electronic structure calculations and an anharmonic theoretical treatment of nuclear motions on extended potential energy surfaces. The complexes are formed by “ligand exchange” reactions of X− · (H2O)n clusters with HOCl molecules at low pressure (∼10−2 mbar) in a radio frequency ion guide. The spectra generally feature many bands in addition to the fundamentals expected at the double harmonic level. These “extra bands” appear in patterns that are similar to those displayed by the X− · HOD analogs, where they are assigned to excitations of nominally IR forbidden overtones and combination bands. The interactions driving these features include mechanical and electronic anharmonicities. Particularly intense bands are observed for the v = 0 → 2 transitions of the out-of-plane bending soft modes of the HOCl molecule relative to the ions. These involve displacements that act to break the strong H-bond to the ion, which give rise to large quadratic dependences of the electric dipoles (electronic anharmonicities) that drive the transition moments for the overtone bands. On the other hand, overtone bands arising from the intramolecular OH bending modes of HOCl are traced to mechanical anharmonic coupling with the v = 1 level of the OH stretch (Fermi resonances). These interactions are similar in strength to those reported earlier for the X− · HOD complexes.
Frequency-stabilized Faraday laser with 10−14 short-term instability for atomic clocks
Authors: Chang Pengyuan , Shi Hangbo , Miao Jianxiang , Shi Tiantian , Pan Duo , Luo Bin , Guo Hong , Chen Jingbiao
Published: April 2022

In this Letter, stabilizing a Faraday laser frequency to the atomic transition is proposed and experimentally demonstrated, where the Faraday laser can work at single- or dual-frequency modes. High-resolution spectroscopy of a cesium atom induced by a Faraday laser is obtained. By stabilizing a Faraday laser with atomic spectroscopy, the frequency fluctuations of the Faraday laser are suppressed without the need of a high-cost Pound–Drever–Hall system. The fractional frequency Allan deviation of the residual error signal is 3 × 10−14/τ at the single-frequency mode. While at the dual-frequency mode, the linewidth of the beat-note spectra between the two modes of the Faraday laser after locking is narrowed to be 85 Hz, which is an order of magnitude better than the free-running linewidth. It can be used for microwave atomic clocks and may have the potential to be used in the application of optical microwave generation when the performance is further improved.
Unsteady coating flow on a rotating cylinder in the presence of an irrotational airflow with circulation
Authors: Mitchell Andrew J. , Duffy Brian R. , Wilson Stephen K.
Published: April 2022

Unsteady two-dimensional coating flow of a thin film of a viscous fluid on the outside of a uniformly rotating horizontal circular cylinder in the presence of a steady two-dimensional irrotational airflow with circulation is considered. The analysis of this problem by Newell and Viljoen [Phys. Fluids 31(3), 034106 (2019)], who sought to generalize the work of Hinch and Kelmanson [Proc. R. Soc. London, Ser. A 459(2033), 1193–1213 (2003)] to include the effect of the airflow, is revisited. In contrast with the claim of Newell and Viljoen that the flow is conditionally unstable (in the sense that the solution for the film thickness grows without bound for certain values of the physical parameters), it is shown that, in fact, the film remains unconditionally stable in the presence of the airflow.
Anomalous Hall effect superimposed in polycrystalline SrRuO3 thick film
Authors: Tian Yingyi , Wang Shuanhu , Wei Xiangyang , Yang Ruishu , Jin Kexin
Published: April 2022

The electric, magnetic, and thermal properties of transition metal oxide films can be modulated by introducing polycrystalline at the macroscopic grain boundaries. Based on these points, in this work, we studied the two-channel anomalous Hall effect (AHE) in polycrystalline ferromagnetic SrRuO3 (SRO) films. The magnetic regions with different crystal directions have different coercivities, resulting in two opposite AHE channels in the polycrystalline SRO layer. However, single-crystal SRO films prepared under the same conditions are found to exhibit only one AHE. The superposition of the two AHE leads to the hump-like behavior of the Hall resistance loop, which is caused by the change of crystalline. This observation provides a new way to explain the hump-like feature of SRO.
Photoelectron imaging of PtI2− and its PtI− photodissociation product
Authors: Gibbard Jemma A. , Verlet Jan R. R.
Published: April 2022

The photoelectron imaging of PtI2− is presented over photon energies ranging from hν = 3.2 to 4.5 eV. The electron affinity of PtI2 is found to be 3.4 ± 0.1 eV, and the photoelectron spectrum contains three distinct peaks corresponding to three low-lying neutral states. Using a simple d-block model and the measured photoelectron angular distributions, the three states are tentatively assigned. Photodissociation of PtI2− is also observed, leading to the formation of I− and of PtI−. The latter allows us to determine the electron affinity of PtI to be 2.35 ± 0.10 eV. The spectrum of PtI− is similarly structured with three peaks which, again, can be tentatively assigned using a similar model that agrees with the photoelectron angular distributions.
Numerical observation and analytical formulation of droplet impact and spreading around the thin vertical cylinder
Authors: Sahoo Prakasha Chandra , Senapati Jnana Ranjan , Rana Basanta Kumar
Published: April 2022

The dynamic characteristics of a water droplet impact on a thin vertical dry solid cylinder are delineated numerically. Finite volume-based axisymmetric simulations are carried out by employing the volume-of-fluid method to predict complex hydrodynamic behaviors. To simulate the present computational work, the conservation equations of mass, momentum, and volume fraction are solved. The droplet surface undergoes a continuous deformation during impact to the thin cylindrical target by resulting in various crucial stages: free fall, hitting, cap formation, encapsulation, uncovering, and detachment. The range of cylinder-to-droplet diameter ratio (Dc/Do) is considered to be from 0.13 to 0.4 for the present computational study to observe different deformation patterns of the droplet. The influence of contact angle (θ), Dc/Do, We, Oh, and Bo on the maximum deformation factor is elucidated from the numerical results. The findings show that the maximum deformation factor increases with the increasing We and the reducing contact angle. An analytical model has been formulated to elucidate the maximum deformation factor, which shows an excellent agreement with the numerical results. Furthermore, a correlation was developed to predict maximum deformation factors in terms of θ, Dc/Do, We, and Oh, which operates exceptionally well within ±1% of the computational data.
Magnetic interlayer coupling between ferromagnetic SrRuO3 layers through a SrIrO3 spacer
Authors: Wysocki Lena , Ilse Sven Erik , Yang Lin , Goering Eberhard , Gunkel Felix , Dittmann Regina , van Loosdrecht Paul H. M. , Lindfors-Vrejoiu Ionela
Published: April 2022

A key element to tailor the properties of magnetic multilayers is the coupling between the individual magnetic layers. In the case of skyrmion hosting multilayers, coupling of skyrmions across the magnetic layers is highly desirable. Here, the magnetic interlayer coupling was studied in epitaxial all-oxide heterostructures of ferromagnetic perovskite SrRuO3 layers separated by spacers of the strong spin–orbit coupling oxide SrIrO3. This combination of oxide layers is being discussed as a potential candidate system to host Néel skyrmions. First order reversal curve (FORC) measurements were performed in order to distinguish between magnetic switching processes of the individual layers and to disentangle the signal of soft magnetic impurities from the sample signal. Additionally, FORC investigations enabled us to determine whether the coupling between the magnetic layers is ferromagnetic or antiferromagnetic. The observed interlayer coupling strength was very weak for the heterostructure with a two monolayer (ML) thick SrIrO3 spacer, and no coupling was observed for spacers of 6 and 12 ML thickness. The decoupling of the magnetic SrRuO3 layers due to the SrIrO3 spacer is a disadvantage for the study of skyrmions in such multilayers and indicates that other oxides have to be identified for realizing strong magnetic coupling.
Preliminary benchmarks and analysis of boundary conditions in a trenched microstructured silicon radiation detector
Authors: Sharma Sanchit , Laramore Diego , Ochs Taylor , McGregor Douglas S. , Bellinger Steven L. , McNeil Walter J. , Bahadori Amir A.
Published: April 2022

Microstructured neutron detectors have the benefit of enhanced neutron detection efficiency as compared to planar devices, achieved by etching 6LiF-filled trenches on the top surface of a silicon PIN diode. This sensor geometry results in a complex electric field distribution and depletion characteristics within the diode under reverse bias. For the first time on record, the effects of a fixed oxide charge on the microstructured device depletion characteristics and mobile carrier transport is investigated. Prototype detectors were fabricated with non-conformal surface doping. Capacitance voltage and current voltage measurements were performed for these prototypes and compared with COMSOL Multiphysics simulations. A spectral response from an 241Am alpha particle source was acquired and analyzed. It was found that monoenergetic alpha particles produce three prominent peaks in the pulse height spectrum output by the device. The peaks were confirmed by simulations to correlate with dead layers and incident trajectories into the microstructure. It was also found that significant differences in pulse rise time result, corresponding with events arriving in a low-field region in the fins and a high-field region in the bulk. Geant4 was utilized for radiation transport, interaction modeling, and benchmarking the spectral data. The results of this simulation work provide confidence in the ability to attain and benchmark electrical characteristics and spectral data for semiconductor radiation detectors employing complex microstructures.
On the Lagrangian dynamics of saliva particles during normal mouth breathing
Authors: Oaks Wayne R. , Craig Jonathan , Duran Christin , Sotiropoulos Fotis , Khosronejad Ali
Published: April 2022

The flow and saliva particulate transport dynamics during normal human breathing through the mouth are simulated numerically using an Eulerian large-eddy simulation (LES) approach for the flow coupled with a Lagrangian approach for the transport of saliva particles. The coupled Eulerian–Lagrangian (EL) simulation results reveal new striking insights into the rich dynamics of the Lagrangian coherent structures (LCS) that arise from saliva particles during normal breathing. Specifically, they uncover a new time-periodic mechanism via which particles are introduced into the flow as individual breathing pulses and accumulate to form a slowly propagating vortex front that persists long distances away from the source. The simulated LCS reveal a wealth of recurrent material motion through which the biosols propagate forward while their cloud expands laterally with a slowly evolving vortex front. Also, the finite-time Lyapunov exponent (FTLE) field of human breathing was calculated using the flow map from the LES velocity field. The ridges of the calculated FTLE field revealed distinct hyperbolic LCS, which closely resemble trajectories of saliva particles obtained from the coupled EL simulation. Finally, simulation results for normal breathing with a non-medical face mask show that the mask can effectively disrupt the formation of coherent particle surfaces and, thus, effectively limit saliva particle propagation.
Oscillation quenching in diffusively coupled dynamical networks with inertial effects
Authors: Zou Wei , Chen Yuxuan , Senthilkumar D. V. , Kurths Jürgen
Published: April 2022

Self-sustained oscillations are ubiquitous and of fundamental importance for a variety of physical and biological systems including neural networks, cardiac dynamics, and circadian rhythms. In this work, oscillation quenching in diffusively coupled dynamical networks including “inertial” effects is analyzed. By adding inertia to diffusively coupled first-order oscillatory systems, we uncover that even small inertia is capable of eradicating the onset of oscillation quenching. We consolidate the generality of inertia in eradicating oscillation quenching by extensively examining diverse quenching scenarios, where macroscopic oscillations are extremely deteriorated and even completely lost in the corresponding models without inertia. The presence of inertia serves as an additional scheme to eradicate the onset of oscillation quenching, which does not need to tailor the coupling functions. Our findings imply that inertia of a system is an enabler against oscillation quenching in coupled dynamical networks, which, in turn, is helpful for understanding the emergence of rhythmic behaviors in complex coupled systems with amplitude degree of freedom.
Real-time feedback stall control of an airfoil at large Reynolds numbers using linear genetic programming
Authors: Passaggia Pierre-Yves , Quansah Asamaning , Mazellier Nicolas , Maceda Guy Y. Cornejo , Kourta Azeddine
Published: April 2022

Machine learning control is applied in real-time to an airfoil equipped with variable-velocity jets and pressure sensors in a closed-loop wind tunnel. The objective of the control is to improve the lift-to-drag ratio using an array of variable velocity jets located at the leading edge of the wing model. Pressure sensors are located along the chord, at mid-span, and are used in a feedback control strategy where the symbolic control laws are optimized using a linear genetic programming control (LGPC) algorithm. For angles of attack at the onset of stall, we show that the best control law is able to outperform the best open-loop control strategy in the case of a single-input multiple-output control loop. Results are reported for Reynolds numbers at both half a million and one million. In particular, the lift-to-drag ratio is improved by 4% compared to the best open-loop strategy, which corresponds to a relative increase by a factor 3. In the case of leading-edge separation conditions, LGPC builds a control law performing similarly to the best open-loop strategy while minimizing the actuation power. This study suggests that in order to improve the control authority, the LGPC strategy is sufficiently mature. This control methodology highlights that in order to improve the aerodynamic performances, novel fluidic actuators providing access to the orientation of the jets could enable breakthroughs for high-Reynolds-number experimental demonstrators.
Thermocapillary-driven dynamics of a free surface in microgravity: Response to steady and oscillatory thermal excitation
Authors: Gligor D. , Salgado Sánchez P. , Porter J. , Tinao I.
Published: April 2022

A numerical analysis of the thermocapillary-driven dynamics of a free surface in microgravity is presented for an open container of liquid subjected to steady or oscillatory thermal excitation. The response to this forcing is analyzed for parameters representative of common silicone oils. In contrast to previous investigations, we permit large-scale unconstrained motion of the contact points and deformation of the free surface, which allows us to study the interaction between free surface dynamics and thermocapillary flow. First, the response of the free surface to steady thermal excitation is considered and characterized by the asymmetry of the contact points. Linear dependence of this asymmetry on the applied Marangoni number is found, which is amplified by the vibroequilibria effect when supplemental (high-frequency) vibrations are introduced. In low-viscosity liquids, the transient dynamics of the free surface includes sloshing modes, suggesting that thermal modulation may be used to excite them. The free surface response to oscillatory thermal excitation is then studied for a wide range of parameters, including variations in contact angle β, viscosity ν, container length L, and fluid height H. We perform a frequency analysis and obtain Bode-type diagrams for the contact point oscillations, characterizing the low-frequency response by its amplitude and phase with respect to the thermal forcing, and demonstrate a resonance peak corresponding to the principal sloshing mode. Overall, these results indicate the potential of oscillatory thermal excitation for fluid control in microgravity.
Predicting and optimizing multirow film cooling with trenches using gated recurrent unit neural network
Authors: Wang Yaning , Wang Zirui , Wang Wen , Li Honglin , Shen Weiqi , Cui Jiahuan
Published: April 2022

The film cooling of cylindrical holes embedded in transverse trenches under superposition has shown promise for protecting the critical components of a high-pressure turbine from thermal damage. To optimize the relevant parameters and provide a suitable film cooling strategy, it is important to predict the effectiveness of lateral-averaged adiabatic film cooling with the trench effect on the surface of a blade. However, high-fidelity semi-empirical correlations for film cooling under superposition conditions with a trench have rarely been examined. This study establishes a gated recurrent unit (GRU) neural network model to predict the effectiveness of lateral-averaged film cooling under multiple-row superposition conditions with a trench. In general, a GRU neural network model is built with a large sequence of one-dimensional parameters, including the depth and width of the trench, compound angle, location of the hole, and blowing ratio. The computational fluid dynamics (CFD) method is used to provide a training dataset for the model. After careful testing and validation, the results predicted by the GRU agreed well with the CFD results. Moreover, the performance and robustness of the GRU were better than those of other recurrent neural network models, such as the long short-term memory model. Integrated with the GRU model, the sparrow search algorithm was adopted to optimize the parameters of the trench. The film cooling effectiveness of the optimized case improved by 1.6% compared with the best case, 28.5% compared with the worst case in dataset, and 23.5% compared with the no-trench case.
Pore-scale study of three-phase displacement in porous media
Authors: Zhu Xiaofei , Chen Li , Wang Sen , Feng Qihong , Tao Wenquan
Published: April 2022

Carbon capture, utilization, and storage have been an effective way to deal with global climate issues. Injecting CO2 into depleted oil reservoirs can reach the dual goal of carbon storage and enhanced oil recovery. To optimize the gas injection strategy, it is necessary to understand the underlying mechanisms of three-phase fluid flow of oil, water, and gas. In this study, a lattice Boltzmann color gradient model is used to investigate the pore-scale three-phase displacement process in porous media. Gas is injected into the porous domain initially occupied by water and oil. Typical microscopic behaviors, including coalescence and split-up, pinch-off, double and multiple displacement, as well as parallel flow, are identified and discussed. Effects of water content (ϕ), capillary number (Ca), wettability and viscosity ratio (M) on the flow pattern, and oil recovery rate are explored. The oil ganglia inhibit the development of gas fingers, causing stronger viscous fingering characteristics with increasing ϕ. The fingering pattern is located in the crossover zone for the Ca from 5 × 10−5 to 5 × 10−4. As ϕ increases, the oil recovery rate reduces. The oil ganglia tend to occupy small pores as oil wettability enhanced, making it more difficult to be drained out. The reduction of oil viscosity is beneficial to improve connectivity, thereby effectively enhancing the oil recovery. Finally, the CO2 storage rate is also evaluated. It is found that the storage rate is very sensitive to the initial oil–water distributions. In general, the storage rate increases as ϕ decreases, Ca increases, and oil wettability enhances.
Dual function spin-wave logic gates based on electric field control magnetic anisotropy boundary
Authors: Wang Kang , Hu Shaojie , Gao Fupeng , Wang Miaoxin , Wang Dawei
Published: April 2022

Spin waves (SWs) have been considered a promising candidate for encoding information with lower power consumption. Here, we propose dual function SW logic gates, one unit cell with two synchronized logic operation functions, based on the electric field controlling of the SW propagation in the Fe film of a Fe/BaTiO3 heterostructure by the motion of a magnetic anisotropy boundary. We show micromagnetic simulations to validate the and–or and nand–nor logic gates. Our research may find a path for simplifying integrated logic circuits using such dual function SW logic gates.
Adsorption of molecular iodine on the Ag(111) surface: Phase transitions, silver reconstruction, and iodide growth
Authors: Andryushechkin B. V. , Pavlova T. V.
Published: April 2022

Room temperature adsorption of molecular iodine on Ag(111) has been studied by scanning tunneling microscopy (STM), low energy electron diffraction, Auger electron spectroscopy with factor analysis, and density functional theory (DFT). At the chemisorption stage, iodine first forms a (3×3)R30° structure. Further iodine dosing leads to continuous commensurate–incommensurate phase transition, taking place via the formation of striped superheavy domain walls. As a result, the uniaxially compressed (13 ×3-R30°) phase is formed at an iodine coverage (θ) of 0.38 ML. At θ > 0.38 ML, first-order phase transition begins, leading to the formation of hexagonal moiré-like phases, which exhibit an anomalously large corrugation in STM (0.8–2.3 Å). In the range of 0.40–0.43 ML, the compression of hexagonal phases occurs, which ends at the formation of the (7 × 7)R21.8° structure at saturation. The DFT calculations allow us to explain the anomalous atomic corrugation of the hexagonal phases by the strong violation of the atomic structure of the substrate including up to ten layers of silver. Iodine dosing above 0.43 ML leads to the growth of 2D islands of silver iodide. The STM images of the silver iodide surface demonstrate a clear visible hexagonal superstructure with a periodicity of 25 Å superimposed with a quasi-hexagonal atomic modulation. DFT calculations of the atomic structure of AgI islands point to the formation of a sandwich-like double layer honeycomb structure similar to the case of I/Ag(100).
Heteroleptic lanthanide(III) complexes: synthetic utility and versatility of the unsubstituted bis-scorpionate ligand framework
Authors: Chowdhury Tajrian , Horsewill Samuel J. , Wilson Claire , Farnaby Joy H.
Published: April 2022

The unsubstituted bis-hydrotris(1-pyrazolyl)borate) (Tp) ligand framework has been used to synthesise a range of heteroleptic Ln(III) coordination complexes [Ln(Tp)2(X)]. The precursor complexes [Ln(Tp)2(OTf)] 1-Ln (Ln = Y, Eu, Gd, Yb; OTf = triflate) were synthesised by reaction of Ln(OTf)3 with two equivalents of K(Tp). The 8-coordinate β-diketonate complexes [Ln(Tp)2(hfac)] 2-Ln (Ln = Y, Eu, Yb; hfac = hexafluoroacetylacetonate) were synthesised from Ln(OTf)3 by reacting 1-Ln generated in situ with an equivalent of K(hfac). The 7-coordinate amide complexes [Ln(Tp)2(N″)] 3-Ln (Ln = Y, Yb; N″ = bis(trimethylsilyl)amide) were synthesised from 1-Ln by reaction with K(N″). Reactivity of 3-Ln towards protonolysis was demonstrated by the isolation of the hydroxide dimer [{Y(Tp)2(μ-OH)}2] 4-Y from adventitious reaction with water and the aryloxide complex [Ln(Tp)2(OAr)] 5-Ln (Ln = Y, Yb; OAr = 2,6-tBu2-4-Me-phenoxide) from reaction with H(OAr). Full characterisation data are presented for all complexes, including solid-state molecular structure determination by single-crystal X-ray diffraction.
Synthesis of heteroleptic yttrium and dysprosium 1,2,4-tris(trimethylsilyl)cyclopentadienyl complexes
Authors: Corner Sophie C. , Goodwin Conrad A. P. , Ortu Fabrizio , Evans Peter , Zhang Hongrui , Gransbury Gemma K. , Whitehead George F. S. , Mills David P.
Published: April 2022

We report the synthesis of heteroleptic dysprosium complexes of the 1,2,4-tris(trimethylsilyl)cyclopentadienyl ligand (Cp‴={C5H2(SiMe3)3-1,2,4}), and diamagnetic yttrium analogues, by salt metathesis protocols from KCp‴ and molecular lanthanoid halide or borohydride precursors: [{Ln(Cp‴)2(μ-Cl)2K}2]∞ (1-Ln; Ln = Y, Dy), [Ln(Cp‴)2(THF)(Cl)] (2-Ln; Ln = Y, Dy), [Y(Cp‴)2(η3-C3H5)] (3-Y), [Y(Cp‴)(BH4)2(THF)] (4-Y), [Dy(Cp‴)(BH4)(μ-BH4)]4 (5-Dy) and [Ln(Cp‴)2(BH4)] (6-Ln; Ln = Y, Dy); several crystals of [Dy(Cp‴)2(BH4)(THF)] (7-Dy) formed on one occasion during the isolation of 6-Dy. Efforts to prepare the isolated lanthanoid metallocenium cations [Ln(Cp‴)2]+ for Y and Dy were not successful by the anion abstraction methods investigated herein; however, several crystals of the contact ion-pair complex [Y(Cp‴)2{(μ-Ph)2BPh2}] (8-Y) formed from the reaction of 3-Y with [NEt3H][BPh4]. On one occasion during the preparation of 3-Y we isolated several crystals of [Mg(Cp‴)(THF)(μ-Cl)]2. Complexes 1–6 and [NEt3H][BPh4] were all structurally authenticated by single crystal XRD and characterised by IR spectroscopy and elemental analysis, with magnetic susceptibility for dysprosium complexes determined by the Evans method, and yttrium analogues studied by multinuclear NMR spectroscopy; complexes 7-Dy, 8-Y, and [Mg(Cp‴)(THF)(μ-Cl)]2 were characterised by single crystal XRD only. The magnetic properties of 5-Dy were probed by SQUID magnetometry and ab initio calculations.
Transcriptome-wide subtyping of pediatric and adult T cell acute lymphoblastic leukemia in an international study of 707 cases
Authors: Dai Yu-Ting , Zhang Fan , Fang Hai , Li Jian-Feng , Lu Gang , Jiang Lu , Chen Bing , Mao Dong-Dong , Liu Yuan-Fang , Wang Jin , Peng Li-Jun , Feng Chong , Chen Hai-Feng , Mu Jun-Xi , Zhang Qun-Ling , Wang Hao , Ariffin Hany , Moy Tan Ah , Wang Jing-Han , Lou Yin-Jun , Chen Su-Ning , Wang Qian , Liu Hong , Shan Zhe , Matsumura Itaru , Miyazaki Yasushi , Yasuda Takahiko , Dou Li-Ping , Yan Xiao-Jing , Yan Jin-Song , Yeoh Allen Eng-Juh , Wu De-Pei , Kiyoi Hitoshi , Hayakawa Fumihiko , Jin Jie , Wang Sheng-Yue , Sun Xiao-Jian , Mi Jian-Qing , Chen Zhu , Huang Jin-Yan , Chen Sai-Juan
Published: April 2022

Significance

We provide transcriptomic insights into differences between pediatric and adult T cell acute lymphoblastic leukemia (T-ALL) patients through an international collaborative effort integrating RNA-sequencing data of 707 patients. Ten subtypes were identified, each characterized by distinct gene mutation profiles and dysregulated expression signatures of leukemogenic factors, and associated with T cell development stages. Adult T-ALL tends to have characteristics of early T cell precursor ALL, mostly corresponding to the mixed phenotype acute leukemia, whereas pediatric T-ALL shows a wide spectrum of aberrant molecular features, from early T cell precursor to mature T cell compartments. Our findings have important implications for disease mechanism of T-ALL that differs between pediatric and adult patients, facilitating further refined targeted therapy.
Numerical study of singlet delta oxygen (O2(a1Δg)) generation and transport in the He/O2 atmospheric pressure plasma jet
Authors: Jiang Yuanyuan , Wang Yanhui , Zhang Jiao , Wang Dezhen
Published: April 2022

This paper investigates the spatial-temporal evolution and the transport of the singlet delta oxygen (O2(a1Δg)) of an atmospheric pressure plasma jet using a 2D fluid modeling. The plasma jet is produced in pure helium or helium with small oxygen admixtures (no bigger than 2%), by applying a constant DC voltage of +5 kV on the annular electrode. It is found that, at the 0.7% O2 admixture, a higher O2(a1Δg) density is obtained inside the tube before the jet impacts the substrate. After the jet propagates along the substrate surface, the peak O2(a1Δg) density is transferred from the tube to the gap. Varying the O2 admixtures percentage in the working gas changes the O2(a1Δg) spatial distribution. The O2(a1Δg) with two thinner edges is dominantly produced in the helium–air mixing layer for pure helium. The addition of O2 in the working gas leads to O2(a1Δg) production in the tube. Meanwhile, the thickness of the O2(a1Δg) edges increases in the helium–air mixing layer. But the radius of the O2(a1Δg) density channel continuously reduces with the O2 admixture. The O2(a1Δg) density and its surface flux first increase within the 0.7% O2 admixture and then decreases with the further augment of the O2 admixture. The influence of the gas flow velocity on the production and transport of O2(a1Δg) is also studied. Increasing the gas flow velocity changes the spatial distribution of the O2(a1Δg) density from the solid structure to the annular structure in the gap. At the same time, lower volume average density and instantaneous flux are obtained at larger gas flow velocity.
Transparent metasurface for wideband backward scattering reduction with synthetic optimization algorithm
Authors: Sui Sai , Wang Jiafu , Pang Yongqiang , Zhang Jieqiu , Xu Zhuo , Qu Shaobo
Published: April 2022

An optical transparent metasurface for wideband backward scattering reduction with a synthetic optimization method is proposed, which makes full use of the simultaneity of electromagnetic absorption and interference suppression, so that backward scattering can be flexibly manipulated. To validate the design procedure, a metasurface with optical transparency is designed, fabricated and experimentally tested, which significantly enhances the efficiency in the frequency range of 6.2–20.8 GHz and exhibits about 79.5% averaged transmittance of optical transparency in the wavelength range of 380–780 nm. The proposed optical transparent wideband backward scattering reduction metasurface reveals an alternative opportunity for effective manipulation of microwaves.