bluuebunny/crossref_metadata_2025 huggingface dataset:
Communication satellite resource scheduling based on improved whale optimization algorithm
Authors: Liu Wenwen , Xiong Wei , Han Chi
Published: January 2022

Under the background of increasing pressure of satellite communication support, reasonable and efficient dispatch of communication satellite resources is an important means to improve the utilization efficiency of communication resources. Aiming at the resource scheduling task requirements of geostationary orbit communication satellite system, communication satellite resource scheduling (CSRS) model is established first of all, based on this, advances a kind of CSRS method based on improved whale optimization algorithm. In this method, the detection and search strategy is proposed and the crossover mutation operator is used to avoid the algorithm falling into local optimum. Simulation results show that IWOA can effectively improve the quality and stability of satellite resource scheduling.
Improved ant colony algorithm for path planning of fixed wing unmanned aerial vehicle
Authors: Zhao Hongchao , Zhao Jianzhong
Published: January 2022

Aiming at the problems of long search time and local optimal solution of ant colony algorithm (ACA) in the path planning of unmanned aerial vehicle (UAV), an improved ant colony algorithm (IACA) was proposed from the aspects of simplicity and effectiveness. The flight performance constraints of fixed wing UAVs were treated as conditions of judging whether the candidate expanded nodes are feasible, thus the feasible nodes’ number was reduced and the search efficiency was effectively raised. In order to overcome the problem of local optimal solution, the pheromone update rule is improved by combining local pheromone update and global pheromone update. The heuristic function was improved by integrating the distance heuristic factor with the safety heuristic factor, and it enhanced the UAV flight safety performance. The transfer probability was improved to increase the IACA search speed. Simulation results show that the proposed IACA possesses stronger global search ability and higher practicability than the former IACA.
Research on dairy products detection based on machine learning algorithm
Authors: Zhang Yang , Zhang Lei , Ma Yabin , Guan Jinsen , Liu Zhaoxia , Liu Jihui
Published: January 2022

In this study, an electronic nose model composed of seven kinds of metal oxide semiconductor sensors was developed to distinguish the milk source (the dairy farm to which milk belongs), estimate the content of milk fat and protein in milk, to identify the authenticity and evaluate the quality of milk. The developed electronic nose is a low-cost and non-destructive testing equipment. (1) For the identification of milk sources, this paper uses the method of combining the electronic nose odor characteristics of milk and the component characteristics to distinguish different milk sources, and uses Principal Component Analysis (PCA) and Linear Discriminant Analysis , LDA) for dimensionality reduction analysis, and finally use three machine learning algorithms such as Logistic Regression (LR), Support Vector Machine (SVM) and Random Forest (RF) to build a milk source (cow farm) Identify the model and evaluate and compare the classification effects. The experimental results prove that the classification effect of the SVM-LDA model based on the electronic nose odor characteristics is better than other single feature models, and the accuracy of the test set reaches 91.5%. The RF-LDA and SVM-LDA models based on the fusion feature of the two have the best effect Set accuracy rate is as high as 96%. (2) The three algorithms, Gradient Boosting Decision Tree (GBDT), Extreme Gradient Boosting (XGBoost) and Random Forest (RF), are used to construct the electronic nose odor data for milk fat rate and protein rate. The method of estimating the model, the results show that the RF model has the best estimation performance( R2 =0.9399 for milk fat; R2=0.9301for milk protein). And it prove that the method proposed in this study can improve the estimation accuracy of milk fat and protein, which provides a technical basis for predicting the quality of dairy products.
Multi scale switchable atrous convolution for target detection based on feature pyramid
Authors: Fang Cheng , Hao Ziqiang , Chen Jiaxin
Published: January 2022

Repeated observation mechanism can effectively solve the problem of low efficiency of feature extraction. By extracting features for many times to strengthen target features, this paper proposed a multi-scale switchable atrous convolution based on feature pyramid, SPC. The head of the detector adopted pyramid convolution mode, constructs 3-D convolution in the feature pyramid, and detected the same target in different pyramid levels by using the shared convolution with different stride changes, which realized the repeated observation of target features on multi-scale. The module optimized the convolution layer, extracted the features of the same image by convolution check of different sizes, and then selected and integrated the extracted results by using switch function, which effectively expanded the field of view of convolution kernel. In this paper, we choosed retinanet as the baseline network, and improved the loss function of focal loss proposed by retinanet to further solved the problem of unbalanced number of samples and sample distribution in the network model. The proposed method performed well on MS coco data set, improved the average accuracy of 9.8% on the basis of retinanet to 48.9%, and achieved FPS of 5.1 in 1333 * 800 images.
Research on hazard installations identification method of power equipment in ship
Authors: Wang Yue , Chen Guobing , Chen Jun , Zeng Guoqing
Published: January 2022

Hazard installation identification was the key and difficult point for ship power equipment safety management. According to the characteristics of ship power equipments, this article analyzed the characteristic of hazard installations, given the range and classification of hazard installation identification. Combining hazard installation checklist and routing inspection, the method and process of hazards installation identification was proposed for ship power equipment, which laid a foundation for its risk assessment and control.
A pedestrian detection algorithm for low light and dense crowd Based on improved YOLO algorithm
Authors: Mao Yitong
Published: January 2022

The real-time pedestrian detection algorithm requires the model to be lightweight and robust. At the same time, the pedestrian object detection problem has the characteristics of aerial view Angle shooting, object overlap and weak light, etc. In order to design a more robust real-time detection model in weak light and crowded scene, this paper based on YOLO, raised a more efficient convolutional network. The experimental results show that, compared with YOLOX Network, the improved YOLO Network has a better detection effect in the lack of light scene and dense crowd scene, has a 5.0% advantage over YOLOX-s for pedestrians AP index, and has a 44.2% advantage over YOLOX-s for fps index.
Improved YOLO v5 with balanced feature pyramid and attention module for traffic sign detection
Authors: Jiang Linfeng , Liu Hui , Zhu Hong , Zhang Guangjian
Published: January 2022

With the development of automatic driving technology, traffic sign detection has become a very important task. However, it is a challenging task because of the complex traffic sign scene and the small size of the target. In recent years, a number of convolutional neural network (CNN) based object detection methods have brought great progress to traffic sign detection. Considering the still high false detection rate, as well as the high time overhead and computational overhead, the effect is not satisfactory. Therefore, we employ lightweight network model YOLO v5 (You Only Look Once) as our work foundation. In this paper, we propose an improved YOLO v5 method by using balances feature pyramid structure and global context block to enhance the ability of feature fusion and feature extraction. To verify our proposed method, we have conducted a lot of comparative experiments on the challenging dataset Tsinghua-Tencent-100K (TT100K). The experimental results demonstrate that the mAP@.5 and mAP@.5:0.95 are improved by 1.9% and 2.1%, respectively.
Behavior monitoring model of kitchen staff based on YOLOv5l and DeepSort techniques
Authors: Guo Xiaotong , Zuo Min , Yan Wenjing , Zhang Qingchuan , Xie Sijun , Zhong Iker
Published: January 2022

Although the monitoring system has been widely used, the actual monitoring task still needs more manpower to complete. This paper takes yolov5l model and deep sort algorithm as the basic framework to identify and track the staff in kitchen environment. We apply a relation construction with detected items and people, then label the relation corresponding to behaviors violate the regulations of kitchen, such as the staff did not wear mask or hat. We train our model and the experimental results show that the model can correctly identify the inappropriate behaviors of staff. The model achieves the time-constrained accuracy of 95.32% in identifying whether the staff wear a hat or not, and the time-constrained accuracy of 96.32% in identifying whether the staff wear mask correctly. The result shows that the proposed model could fulfil monitoring task in this kitchen environment.
Combination of XGBoost and PPLK method for improving the precipitation nowcasting
Authors: Mai Xiongfa , Zhong Haiyan , Li Ling
Published: January 2022

The Precipitation nowcasting can provide high-resolution forecasts of rainfall and hydrometeors in 2 hours and play an important role in risk management for flash flood and debris flow events, but it is a very challenge work. This study proposed a new method which combine of XGBoost method and the PPLK model for precipitation nowcasting (XGB-PPLK). The proposed method was assessed in four different types of storms, and the experimental results show that the XGB-PPLK can improve the probability of detection (POD), as while as reducing the normalized mean square error (NMSE), and maintain the basically equivalent false-alarm ratio (FAR).
Research on the modulation format of 40Gb/s WDM-PON system
Authors: Wang Yilin , Zhang Chunlei
Published: January 2022

In order to meet the transmission needs of WDM-PON system, a WDM-PON full-duplex system based on reflective semiconductor optical amplifier (RSOA) remodulation was constructed in this paper. The downlink transmission rate of the system was 40Gb/s, and the downlink adopted three modulation formats, namely carrier suppression return to zero (CSRZ), optical duobinary (ODB) and quadrary pulse amplitude modulation (PAM4); the uplink transmission rate of the system was 10Gb/s, and the uplink adopted NRZ code. Through the simulation, the transmission performance of the system under these three modulation formats was compared and analysed?and the system uplink/downlink eye diagram and Q-value graph were obtained. The results show that the PAM4 signal has the strongest anti-dispersion capability and the ODB has the highest anti-nonlinear tolerance.
An efficient anonymous group handover authentication protocol for MTC devices for 5G networks
Authors: Yan Xiaobei , Ma Maode
Published: January 2022

Machine Type Communication (MTC) has been emerging for a wide range of applications and services for the Internet of Things (IoT). In some scenarios, a large group of MTC devices (MTCDs) may enter the communication coverage of a new target base station simultaneously. However, the current handover mechanism specified by the Third Generation Partnership Project (3GPP) incur high signalling overhead over the access network and the core network for such scenario. Moreover, other existing solutions have several security problems in terms of failure of key forward secrecy (KFS) and lack of mutual authentication. In this paper, we propose an efficient authentication protocol for a group of MTCDs in all handover scenarios. By the proposal, the messages of two MTCDs are concatenated and sent by an authenticated group member to reduce the signalling cost. The proposed protocol has been analysed on its security functionality to show its ability to preserve user privacy and resist from major typical malicious attacks. It can be expected that the proposed scheme is applicable to all kinds of group mobility scenarios such as a platoon of vehicles or a high-speed train. The performance evaluation demonstrates that the proposed protocol is efficient in terms of computational and signalling cost.
Ship RBF neural network sliding mode PID heading control
Authors: Yu Jiaming , Bu Renxiang , Li Liangqi
Published: January 2022

In view of the inherent non-linearity, complexity, susceptibility to external wind, wave, and current interference of under-driven ships, and the difficulty of adjusting and adjusting control parameters, to improve the performance of ship’s autopilot, a kind of RBF neural network sliding mode variable structure PID controller is designed. Traditional PID control is sensitive to parameter changes, online tuning is difficult, and easy to overshoot. In order to solve this problem, combining the variable structure characteristics of PID, a differential compensation term is added to the integral term to convert the PID control parameters into three parameters with more obvious physical meanings, and then combined with the RBF neural network learning and identification function to realize online tuning and adaptive control of ship control parameters. Using MATLAB software to simulate the container ship “MV KOTA SEGAR” MMG model shows that the designed RBF neural network sliding mode PID controller can effectively eliminate the ship’s lateral deviation caused by external interference such as wind, waves, currents, etc., with high control accuracy,robustness and strong adaptability.
Study on the tool setting method of micro-milling tool based on in-line holography
Authors: Zhang Xianghui , Xu Jinkai , Yu Zhanjiang , Yu Huadong
Published: January 2022

Aiming at the various shortcomings of existing tool setting methods, this paper proposes a coaxial holographic tool setting method for tiny tools. Based on the research and analysis of the principle of holographic imaging and the key issues of holographic images, a set of holographic tool setting detection device for micro milling tool was built, and the micro milling tool measurement was carried out on the five-axis machining center using standard tools. experiment. Experimental results show that the tool setting device can efficiently perform tool setting detection of micro-milling tool. Compared with the measurement results of the high-precision external presetting instrument, the relative error of the contact tool setting instrument is 0.033%, and the relative error of the holographic tool setting prototype is 0.007%, which is more effective in realizing the tool setting of tiny tools. Detection. This result verifies the feasibility of the coaxial holographic tool setting method for micro tool, that is, holographic measurement can be used for high-precision tool setting of micro milling tool.
Structure design and performance analysis of aerostatic thrust bearing with compound restrictors
Authors: Li Yuntang , Ye Yueliang , Li Ruirui , Wang Pengfeng , Zhang Fangfang
Published: January 2022

Aerostatic thrust bearing compensated by multi-orifices and porous material restrictor simultaneously is proposed to improve the static performance of the bearing. Load Carrying Capacity (LCC), stiffness and the flow field characteristics of the bearing are obtained by Computational Fluid Dynamic (CFD) simulation. The influences of supply pressure, orifice number, orifice diameter, orifice distribution, porous material thickness and permeability coefficient on the bearing performance are analysed. It is indicated that LCC and stiffness of the bearing with compound restrictors are much higher than those of the bearing with porous material restrictor or multi-orifice restrictor if gas film thickness is in rational range. The bearing with compound restrictors has better stability than that of the bearing with multi-orifice restrictor. Moreover, the optimum bearing parameters with compound restrictors are given to improving the performance of aerostatic thrust bearing.
Intraoral and dental panoramic imaging: A diagnostic reference level study comparing radiation dose using two dosimeters in Saudi Arabia
Authors: Saeed M.K. , Asiri A.A.M. , Alhamami Q.S. , Alshamrani K.
Published: January 2022

The purpose of this study was to determine local diagnostic reference levels (DRLs) for patients undergoing intraoral and panoramic dental examinations at the intraoral radiology units of the public hospitals in Najran, Saudi Arabia. DRLs were determined based on measurements of dose area product (DAP) at intraoral and dental panoramic radiology units. This study has covered over 47% of the public hospitals in Najran with the intention to establish the local DRLs for all the possible intraoral and panoramic X-ray examinations for children and adults. For intraoral, the values for the estimated DAP ranged from 6 to 70 mGy.cm2 (average: 27.6, 29.8, 39.9 and 39.6 mGy.cm2 for incisive, both premolar and canine, molar upper and lower jaw, respectively). For panoramic, the mean value of DAP is 61.5 and 89.8 mGy.cm2 for paediatric and adult patients, respectively. DRLs were established at the 3rd quartile for incisive, both premolar and canine, molar upper and lower jaw protocols are 29.2, 37.1, 50.2 and 50.1 mGy.cm2, respectively. Furthermore, DRLs for panoramic radiography for paediatric and adult patients are 72.7 and 92.3 mGy.cm2, respectively. The proposed DRLs were comparable to those previously reported in other countries, such as UK and India.
Forschungsprioritäten in der physiotherapeutischen Forschung in Deutschland – Eine systematische Analyse von Publikationen der physioscience der letzten 10 Jahre
Authors: Braun Tobias , Bahns Carolin , Elsner Bernhard , Kopkow Christian
Published: January 2022

Hintergrund Forschungsprioritäten können dazu beitragen, Evidenz in den Bereichen zu entwickeln, die für Patient*innen und Kliniker*innen am wichtigsten sind. Forschungsprioritäten werden jedoch in der biomedizinischen Forschung nur unzureichend berücksichtigt.

Ziel Beschreibung der Berücksichtigung von Forschungsprioritäten in der physiotherapeutischen Forschung in Deutschland.

Methode Analyse von physiotherapeutischen Berichten aus Deutschland, die zwischen 2011 und 2020 in der Fachzeitschrift physioscience publiziert wurden. Für jeden eingeschlossenen Bericht wurde die primäre Forschungsfrage und/oder der Hauptgegenstandsbereich identifiziert und, falls möglich, einem spezifischen Gesundheitszustand zugeordnet. Danach wurde für jeden Bericht geprüft, ob eine gesundheitszustandsspezifische Forschungspriorität (von der James Lind Alliance oder aus wissenschaftlichen Datenbanken) bzw. eine der Top 26 der physiotherapiespezifischen Forschungsprioritäten des britischen Berufsverbandes „The Chartered Society of Physiotherapy (CSP)“ aus 2018 adressiert wurde. Die Datenanalyse erfolgte deskriptiv.

Ergebnisse Es konnten 78 Berichte in die Analyse eingeschlossen werden. Die häufigsten Studientypen waren Übersichtsarbeiten (17/78, 22 %), Beobachtungsstudien (16/78, 21 %) und Umfragen (13/78, 17 %). Für die Analyse der gesundheitszustandsspezifischen Forschungsprioritäten konnten 51 Berichte berücksichtigt werden. In 51 % dieser Berichte (26/51) wurde eine der 10 wichtigsten Forschungsprioritäten des jeweiligen Themengebiets adressiert. In den übrigen Berichten wurde keine gesundheitszustandsspezifische Forschungspriorität berücksichtigt (13/51, 25 %) oder die Priorität gehörte nicht zu den Top Ten (12/51, 24 %).

Für die Analyse der physiotherapeutischen Forschungsprioritäten wurden alle 78 Berichte berücksichtigt. In 21 % dieser Berichte (16/78) wurde eine Top-Ten-Priorität adressiert. In den übrigen Berichten wurde eine weniger wichtige Priorität adressiert (Listenplatz 11–26; 25/78, 32 %) oder das Forschungsthema des Berichts gehörte nicht zu den Top 26 (37/78, 47 %).

Schlussfolgerung Die vorliegende Studie liefert erste Hinweise darauf, dass Forschungsprioritäten in der physiotherapeutischen Forschung in Deutschland nur unzureichend berücksichtigt werden. Ein erheblicher Teil der Forschung scheint somit an den Bedürfnissen von Patient*innen und Kliniker*innen vorbeizugehen. Die Berücksichtigung existierender Forschungsprioritäten und die Entwicklung nationaler Forschungsprioritäten für die Physiotherapie in Deutschland könnten dazu beitragen, den Nutzen der physiotherapeutischen Forschung für die öffentliche Gesundheit zu vergrößern.
Homöopathie und Ambiguitätstoleranz
Authors: Lucae Christian
Published: January 2022

Die vergangenen beiden Jahre waren durch die nicht enden wollende Coronapandemie samt
der damit verbundenen vielfältigen Einschränkungen für alle
Bevölkerungsteile sehr belastend. Die mediale Berichterstattung zur
Gesundheitspolitik hat ein einziges Virus und dessen Auswirkungen so lange durch ein
Brennglas betrachtet, bis unser kollektives Bewusstsein alles andere nur mehr als
nachrangig einsortieren konnte. Im Zuge der Fokussierung auf dieses Thema scheint
die Polarisierung in vielen Gesundheitsfragen größer zu werden. Wenn
irgendwann nur noch die Impfung als das einzig Heilbringende benannt wird und
darüber hinaus unsere Ängste zu einer treibenden Kraft werden,
verharren wir zunehmend in Schwarz-Weiß-Denken und Dogmatismus. Es bleibt
wenig Raum für neue Gedanken und erfrischenden Meinungsaustausch –
oder gar komplementäre Ansätze in der Medizin. Es ist kein Wunder,
dass auch das Homöopathie-Bashing vorangeschritten ist und die Kritik immer
häufiger auf die Formel „Alles Lüge!“ zugespitzt
wird.
Determination of Second Lactate Threshold Using Near-infrared
Spectroscopy in Elite Cyclists
Authors: Salas-Montoro José-Antonio , Mateo-March Manuel , Sánchez-Muñoz Cristóbal , Zabala Mikel
Published: January 2022

The use of near-infrared spectroscopy could be an interesting alternative to
other invasive or expensive methods to estimate the second lactate threshold.
Our objective was to compare the intensities of the muscle oxygen saturation
breakpoint obtained with the Humon Hex and the second lactate threshold in elite
cyclists. Ninety cyclists performed a maximal graded exercise test. Blood
capillary lactate was obtained at the end of steps and muscle oxygenation was
continuously monitored. There were no differences (p>0.05) between
muscle oxygen oxygenation breakpoint and second lactate threshold neither in
power nor in heart rate, nor when these values were relativized as a percentage
of maximal aerobic power or maximum heart rate. There were also no differences
when men and women were studied separately. Both methods showed a highly
correlation in power (r=0.914), percentage of maximal aerobic power
(r=0.752), heart rate (r=0.955), and percentage of maximum heart
rate (r=0.903). Bland-Altman resulted in a mean difference of
0.05±0.27 W·kg–1, 0.91±4.93%,
0.63±3.25 bpm, and 0.32±1.69% for power, percentage of
maximal aerobic power, heart rate and percentage of maximum heart rate
respectively. These findings suggest that Humon may be a non-invasive and
low-cost alternative to estimate the second lactate threshold intensity in elite
cyclists.
Recurrent Skin Ulcers with Facial Dysmorphism and Sinopulmonary Infections: Thinking Beyond Hyper-IgE Syndrome
Authors: Chidambaram Aakash Chandran , Sugumar Kiruthiga , Sundaravel Selvamanojkumar , Ramamoorthy Jaikumar Govindaswamy , Bathula Siddardha , Dutta Usha R.
Published: January 2022

Prolidase deficiency (PD) is a rare inborn error of metabolism causing ulcers and other skin disorders, splenomegaly, developmental delay, and recurrent infections. Most of the literature is constituted of isolated case reports. It occurs due to the mutations in the prolidase gene (PEPD) that result in loss of prolidase activity. We reported here a child who had presented with features compatible with hyper-immunoglobulin E syndrome (HIES) like recurrent skin ulcers, recurrent infections, facial dysmorphism, retained primary teeth, and elevated levels of immunoglobulin E levels but with normal flow cytometric assays, which was later diagnosed as PD.
The Role of Plasminogen Activator Inhibitor Type 1 (PAI-1) in Placenta-Mediated Pregnancy Complications: A Systematic Review
Authors: Agersnap Ida , Nissen Peter H. , Hvas Anne-Mette
Published: January 2022

Plasminogen activator inhibitor type 1 (PAI-1) is a main inhibitor of fibrinolysis. The PAI-1 gene (SERPINE1) harbors genetic variants with the potential of modifying plasma levels of PAI-1. A delicate balance exists between the coagulation and fibrinolytic system, and changes in PAI-1 have been suggested to compromise establishment of a successful pregnancy. Therefore, this systematic review investigated the association between genetic variants and/or plasma levels of PAI-1 and placenta-mediated pregnancy complications. An extensive literature search was conducted in PubMed, Embase, and Web of Science on the 29th of April 2021. All studies underwent quality rating according to The Study Quality Assessment Tools checklist provided by National Heart, Lung and Blood Institute. A total of 71 studies were included, among which 60 studies investigated PAI-1 genotypes and 11 studies measured PAI-1 plasma levels. In 32 out of 59 studies, no association was found between the PAI-1 4G/5G polymorphism (rs1799768) and placenta-mediated pregnancy complications, which was stated as no significant difference in the genotype distribution comparing women with and without placenta-mediated pregnancy complications or no significantly increased odds of placenta-mediated pregnancy complications carrying the 4G/4G or 4G/5G genotype. Eight out of 11 studies reported significantly higher PAI-1 plasma levels in preeclamptic women than in women without preeclampsia. In conclusion, no clear evidence indicates that PAI-1 polymorphisms are associated with placenta-mediated pregnancy complications, and the possible association between high PAI-1 plasma levels and preeclampsia needs further investigations. Thus, investigation of PAI-1 genotypes and PAI-1 plasma levels does not currently seem to have a place in daily clinical practice managing placenta-mediated pregnancy complications.
What We Know (and Do not Know) Regarding the Pathogenesis of Pulmonary Thrombosis in COVID-19
Authors: Lippi Giuseppe , Favaloro Emmanuel J.
Published: January 2022

The clinical course of coronavirus disease 2019 (COVID-19) is often complicated by the onset of venous thrombosis and thromboembolism (VTE), encompassing also pulmonary thrombosis. Recent statistics attests that the cumulative frequency of VTE can be as high as 30% in COVID-19 hospitalized patients, increasing to nearly 40 to 70% (depending on systematic screening) in those with severe illness, mechanical ventilation, or intensive care unit admission. The risk of venous thrombosis seems mostly limited to the active phase of disease, and is directly associated with some genetic (i.e., inherited prothrombotic predisposition) and demographical factors (male sex, overweight/obesity), disease severity (risk increasing progressively from hospitalization to development of severe illness, being the highest in patients needing mechanical ventilation and/or intensive care), presence and extent of pulmonary disease, coexistence of multiple risk factors (immobilization, mechanical ventilation, co- or superinfections), along with increased values of inflammatory and thrombotic biomarkers. At least three different phenotypes of pulmonary thrombosis may develop in COVID-19 patients, one caused by typical embolization from peripheral venous thrombosis (e.g., deep vein thrombosis), a second type triggered by local inflammation of nearby pulmonary tissue, and a third one mostly attributable to the prothrombotic state consequent to the pronounced systemic inflammatory response (i.e., the so-called cytokine storm) that is frequently observed in COVID-19. Although the pathogenesis of these three conditions has different features, their discrimination is essential for diagnostic and therapeutic purposes. The prognosis of COVID-19 patients who develop pulmonary thrombosis is also considerably worse than those who do not, thus probably needing frequent monitoring and more aggressive therapeutic management.
Paving the way for mechanical fabrication of graphether nanoribbons
Authors: Ikenson Ben
Published: January 2022

Electronic properties of armchair-edged graphether nanoribbons revealed to be symmetry-dependent
Giant parametric amplification and spectral narrowing in atomically thin MoS2 nanomechanical resonators
Authors: Lee Jaesung , Shaw Steven W. , Feng Philip X.-L.
Published: January 2022

Pre-amplification of ultrasmall signals directly in the mechanical domain and boosting quality (Q) factors in nanoelectromechanical systems (NEMS) are intriguing scientific questions and technical challenges. These are particularly enticing in resonant NEMS enabled by emerging two-dimensional (2D) layered crystals, toward revealing fundamental limits and potential of 2D NEMS in both science explorations and engineering applications. Fortunately, their ultimately thin nature and unconventional elastic properties offer rich opportunities for manipulating oscillations via parametric and nonlinear effects. Here, we report on the experimental demonstration of giant parametric amplification and spectral linewidth narrowing in atomically thin molybdenum disulfide (MoS2) 2D NEMS resonators vibrating at ∼30–60 MHz. Parametric amplification is examined by photothermally modulating the stiffness of each atomic layer resonator at twice its resonance frequency (2f). Thanks to exceptionally efficient parametric effects in these atomically thin membranes, the parametric amplification of undriven thermomechanical resonance leads to giant parametric gains up to 3605 (71 dB) and spectral linewidth narrowing factors up to 1.8 × 105, before the onset of parametric oscillation. The remarkable parametric amplification and spectral narrowing (including effective Q boosting in the sub-threshold regime) in 2D NEMS validated in this study may open new possibilities for creating ultimately thin yet high-performance resonators and oscillators for signal transduction and sensing in classical and quantum engineering applications.
A derivation of braided C*-tensor categories from gapped ground states satisfying the approximate Haag duality
Authors: Ogata Yoshiko
Published: January 2022

We derive braided C*-tensor categories from gapped ground states on two-dimensional quantum spin systems satisfying some additional condition, which we call the approximate Haag duality.
Buoyancy-modified entrainment in plumes: Theoretical predictions
Authors: Saeed Zeeshan , Weidner Elizabeth , Johnson Blair A. , Mandel Tracy L.
Published: January 2022

A theoretical analysis, based on the self-similar velocity and buoyancy profiles for plumes in the far field region, is conducted to show how buoyancy dually shapes the flow behavior. In particular, it is shown that while buoyancy flux makes a positive contribution to the mean kinetic energy flux, buoyancy also enhances the momentum flux, through which the mean shear is enhanced. This amplifies the loss of mean kinetic energy into turbulent kinetic energy. The ability of buoyancy to increase the range of flow length scales is discussed in terms of its impact on the evolutionary dynamics of the flow structures. It is also shown, as a result of the scaling laws that follow from the analysis, that the ability of buoyancy to strengthen the eddy vorticity in plumes is primarily through its leading order effect of enhancing the mean flow, and hence the mean shear, and less so through its lower order contributions to the baroclinic component of torque. We then provide a perspective on how the small-scale nibbling contribution to the entrainment process is affected by such buoyancy-induced modifications to the mean flow. Finally, key takeaways from the analysis are juxtaposed with the modern-day view provided by the literature on the entrainment process to propose a mechanistic picture of buoyancy-modified entrainment in plumes.
Magnetic turnstiles in nonresonant stellarator divertor
Authors: Punjabi Alkesh , Boozer Allen H.
Published: January 2022

Nonresonant stellarator divertors have magnetic flux tubes, called magnetic turnstiles, that cross cantori, which are fractal remnants of destroyed invariant tori with holes, that lie outside the outermost confining surface. The exiting and entering flux tubes can be adjacent as is generally expected but can also have the unexpected feature of entering or exiting at separate locations of the cantori. Not only can there be two types of turnstiles but pseudo-turnstiles can also exist. A pseudo-turnstile is formed when a cantorus has a sufficiently large, although limited, radial excursion to strike a surrounding chamber wall. The existence of non-adjacent and adjacent turnstiles and pseudo-turnstiles resolves issues that arose in earlier simulations of nonresonant stellarator divertors [A. Punjabi and A. H. Boozer, Phys. Plasmas 27, 012503 (2020)].
Soft bioelectronics for cardiac interfaces
Authors: Tang Xin , He Yichun , Liu Jia
Published: January 2022

Bioelectronics for interrogation and intervention of cardiac systems is important for the study of cardiac health and disease. Interfacing cardiac systems by using conventional rigid bioelectronics is limited by the structural and mechanical disparities between rigid electronics and soft tissues as well as their limited performance. Recently, advances in soft electronics have led to the development of high-performance soft bioelectronics, which is flexible and stretchable, capable of interfacing with cardiac systems in ways not possible with conventional rigid bioelectronics. In this review, we first review the latest developments in building flexible and stretchable bioelectronics for the epicardial interface with the heart. Next, we introduce how stretchable bioelectronics can be integrated with cardiac catheters for a minimally invasive in vivo heart interface. Then, we highlight the recent progress in the design of soft bioelectronics as a new class of biomaterials for integration with different in vitro cardiac models. In particular, we highlight how these devices unlock opportunities to interrogate the cardiac activities in the cardiac patch and cardiac organoid models. Finally, we discuss future directions and opportunities using soft bioelectronics for the study of cardiac systems.
Realignment-free cryogenic macroscopic optical cavity coupled to an optical fiber
Authors: Fedoseev Vitaly , Fisicaro Matteo , van der Meer Harmen , Löffler Wolfgang , Bouwmeester Dirk
Published: January 2022

We present a cryogenic setup where an optical Fabry–Perot resonator is coupled to a single-mode optical fiber with coupling efficiency above 90% at mK temperatures without realignment during cooling down. The setup is prealigned at room temperature to compensate for the thermal contraction and change of the refractive index of the optical components during cooling down. The high coupling efficiency is achieved by keeping the setup rotation-symmetric around the optical axis. The majority of the setup components are made of Invar (FeNi36), which minimizes the thermal contraction. High coupling efficiency is essential in quantum optomechanical experiments.
Ice sintering: Dependence of sintering force on temperature, load, duration, and particle size
Authors: Bahaloo Hassan , Eidevåg Tobias , Gren Per , Casselgren Johan , Forsberg Fredrik , Abrahamsson Per , Sjödahl Mikael
Published: January 2022

We present experiments along with an approximate, semi-analytic, close-form solution to predict ice sintering force as a function of temperature, contact load, contact duration, and particle size during the primary stage of sintering. The ice sintering force increases nearly linear with increasing contact load but nonlinear with both contact duration and particle size in the form of a power law. The exponent of the power law for size dependence is around the value predicted by general sintering theory. The temperature dependence of the sintering force is also nonlinear and follows the Arrhenius equation. At temperatures closer to the melting point, a liquid bridge is observed upon the separation of the contacted ice particles. We also find that the ratio of ultimate tensile strength of ice to the axial stress concentration factor in tension is an important factor in determining the sintering force, and a value of nearly 1.1 MPa can best catch the sintering force of ice in different conditions. We find that the activation energy is around 41.4KJ/mol, which is close to the previously reported data. Also, our results suggest that smaller particles are “stickier” than larger particles. Moreover, during the formation of the ice particles, cavitation and surface cracking is observed which can be one of the sources for the variations observed in the measured ice sintering force.
Kink–ballooning mode in circular tokamak plasma
Authors: Xu Xinliang , Dudson Benjamin
Published: January 2022

Peeling–ballooning modes, which are driven by gradients of parallel current and pressure in the pedestal, are widely accepted as the instability triggering large Edge Localized Modes (ELMs). However, the current-driven mode related to ELMs is not fully understood. This paper is about comparing the kink mode to the peeling mode, and the modified current profiles are specifically made to be simultaneously kink stable/peeling unstable or vice versa so that the two modes (or the modes coupled to peeling modes) can be compared. Caltrans-Corsica is used to generate a series of equilibria with modified edge current profiles. Based on these equilibria, the effects of edge current density on plasma instabilities are studied with the three-field BOUT++ elm-pb code. The results suggest that kink–ballooning modes can drive ELMs in some peeling-stable regions. Compared to the peeling–ballooning mode, kink–ballooning modes have comparatively lower poloidal resonant modes and growth rates at low toroidal mode numbers.
Investigation on cavitation initiation in jet pump cavitation reactors with special emphasis on two mechanisms of cavitation initiation
Authors: Xu Shuangjie , Wang Jiong , Cai Biaohua , Cheng Huaiyu , Ji Bin , Zhang Zuti , Long Xinping
Published: January 2022

Hydrodynamic cavitation is used in various engineering fields, such as water treatment and chemical processing. Cavitation initiation is critical to assessing the cavitation effect in cavitation reactors, so cavitation initiation should be studied to improve cavitation in various fields. This paper investigates the mechanisms and characteristics of cavitation initiation in jet pump cavitation reactors (JPCRs) to intensify the cavitation. A criterion derived for cavitation initiation focuses on the fluctuating pressures caused by the velocity gradients. Experiments show that the criterion predicts low pressure cavitation and strong shear dominant cavitation in a JPCR. Then, the characteristics of these two cavitation mechanisms are investigated for various geometric parameters and operating conditions and a cavitation initiation regime map is developed for JPCR. The results show that cavitation occurs more easily, and the two cavitation mechanisms become increasingly more difficult to distinguish in the JPCR as the inlet pressure increases. The velocity gradient and loss coefficient increase with a decrease in suction pressure, which promotes cavitation. The low pressure cavitation and strong shear dominant cavitation are both more likely when the area ratio is relatively small. The induced pressure spectra further show that the low frequency component dominates during the formation of the low pressure cavitation, while the high frequency component dominates during the formation of the strong shear dominant cavitation. This study clarifies the cavitation mechanisms with special emphasis on the fluctuating pressure and the corresponding characteristics in the JPCR to provide guidance for JPCR applications in industry.
Hybrid particle-in-cell simulations of electromagnetic coupling and waves from streaming burst debris
Authors: Keenan Brett D. , Le Ari , Winske Dan , Stanier Adam , Wetherton Blake , Cowee Misa , Guo Fan
Published: January 2022

Various systems can be modeled as a point-like explosion of ionized debris into a magnetized, collisionless background plasma—including astrophysical examples, active experiments in space, and laser-driven laboratory experiments. Debris streaming from the explosion parallel to the magnetic field may drive multiple resonant and non-resonant ion–ion beam instabilities, some of which can efficiently couple the debris energy to the background and may even support the formation of shocks. We present a large-scale hybrid (kinetic ions + fluid electrons) particle-in-cell simulation, extending hundreds of ion inertial lengths from a 3D explosion, that resolves these instabilities. We show that the character of these instabilities differs notably from the 1D equivalent by the presence of unique transverse structure. Additional 2D simulations explore how the debris beam length, width, density, and speed affect debris–background coupling, with implications for the generation of quasi-parallel shocks.
A transient intrusion flow on a cooled horizontal surface
Authors: Qi Yi , Chen Enhui , Xu Feng
Published: January 2022

We investigate the dynamical evolution and thermal processes of a fluid on a suddenly cooled horizontal surface subjected to an isothermal or an isoflux condition. A simple scaling analysis is performed to study an intrusion flow induced by a suddenly cooled surface. Analytical results demonstrate that there exist two scenarios for the dynamical evolution and thermal processes of such an intrusion flow for Prandtl numbers smaller than unity. In a typical case, the intrusion flow could travel under different regimes such as the “conduction regime,” “accelerating convection–inertial regime,” “steady convection–inertial regime,” and “decelerating convection–viscous regime,” respectively. A set of scaling laws under different regimes have been presented based on scaling analysis. In addition, a two-dimensional numerical simulation is conducted to validate the scaling laws. The scaling laws are in agreement with our numerical results.
Enhanced phase separation in PEDOT:PSS hole transport layer by introducing phenylethylammonium iodide for efficient perovskite solar cells
Authors: Zhang Yuanyuan , Shin Insoo , Li Fuqiang , Liu Fengwu , Kim Danbi , Yang Hyun-Seock , Lee Bo Ram , Lee Byoung Hoon , Hwang In-Wook , Park Sung Heum
Published: January 2022

In this study, we investigated property change in the poly(3,4-ethylenedioxythiophene) poly-styrene sulfonate (PEDOT:PSS) layer by introducing phenylethylammonium iodide (PEAI) in inverted p-i-n perovskite solar cells. After depositing PEAI on the PEDOT:PSS layer, PEA+ induces a screening effect and decreases the interaction between PSS and PEDOT chains, accelerating their phase separation. The separated PSS chains are drawn to the film surface owing to the Coulombic attraction between PEA+ and –SO3− groups. Additionally, the I− ion (−1 value) of PEAI is oxidized to I2 (0 value) after annealing, which contributes to the separation of PEDOT and PSS units. The modified PEDOT:PSS presents a smooth morphology, which contributes to the construction of improved perovskite film quality with enlarged grains and decreased trap defects, accelerating hole extraction and migration efficiency. Moreover, PEAI modification could also realize a favorable energy level match between the PEDOT:PSS layer and perovskite active layer. Consequently, the power conversion efficiency is enhanced from 15.95% to 18.71%, and light and thermal stabilities are improved for the PEAI-modified device.
Unraveling the obscure electronic transition and tuning of Fermi level in Cu substituted Bi2Te3 compound
Authors: Dan Sambhab , Kumar Shiv , Dan Shovan , Pal Debarati , Patil S. , Verma Abhineet , Saha Satyen , Shimada Kenya , Chatterjee S.
Published: January 2022

Observation of a broad peak in the temperature (T) dependent resistivity (ρ) in Cu substituted Bi2Te3 has been reported earlier, though its origin remains obscured to date. Our investigation reveals that an electronic phase transition accompanied by Fermi level tuning primarily contributes toward the observed ρ(T). The analysis reveals that tuning of the Fermi level affects bulk transport phenomena to produce the unique ρ(T). We have proposed a model to show how the bulk bandgap can affect ρ(T). We have shown that bulk carrier contribution has a greater role in producing such ρ(T), and a detailed discussion supported by temperature dependent ARPES study, Raman study, and XPS study as well as structural study conducted by x-ray diffraction has been presented.
Structural characteristics of the upstream sheath of the ion optics and its application in evaluating the beam performance of an ion thruster
Authors: Li Haolin , Yang Jinyuan , Zhang Liwei , Zhang Siyuan , Sun Anbang
Published: January 2022

To evaluate the extraction capabilities of ion optics and promote the generation of highly collimated ion beams for propulsion, the properties of the upstream sheath of the ion optics and how those properties relate to the beam divergence are investigated numerically and theoretically. The characteristics of the beam divergence at different grid parameters are studied from the behaviors of the impingement current and divergence angle obtained by simulations. Additionally, the simulations indicate the existence of an optimal structure for the upstream sheath of the ion optics, one that corresponds to a moderate focusing effect and a relatively small divergence angle. The plasma densities at the dividing points of different sheath structures are then derived with the matching model of the ion optics and the Child–Langmuir law, coupled with semi-empirical approaches based on the simulation results. According to the theoretical analyses, the range of existence of the most-desirable sheath structure depends on the strength of the penetration of the extraction field, the voltage between the grid apertures, and the distance between the upstream surfaces of the grids. Also, sensitivity analyses are performed with the numerical partial derivatives of the models to investigate how the grid parameters affect the sheath structures. The plasma densities at the dividing points generally vary synchronously with the changes of grid parameters, but the ranges of variations are different. Consequently, the desirable sheath structure and operating conditions of the ion optics can be achieved by correctly adjusting the grid parameters.
Additive Dzyaloshinskii–Moriya interaction in Pt/Co/Re films
Authors: Nomura Akiyo , Gao Tenghua , Haku Satoshi , Ando Kazuya
Published: January 2022

We report the Dzyaloshinskii–Moriya interaction (DMI) in Pt/Co/Re films. By measuring the current-induced hysteresis loop shift, we find that the interfacial DMI in the Pt/Co/Re structure is 2.1 pJ/m, which is stronger than that in Ir/Co/Pt asymmetric multilayers. The large DMI in this system can be attributed to an additive DMI at the Pt/Co and Co/Re interfaces; the Co/Re interface hosts a large DMI whose sign is the same as that at the Pt/Co interface. The additive DMI due to the large DMI at the Co/Re interface is consistent with theoretical predictions. The result provides a way to control the formation of chiral spin textures, such as magnetic skyrmions and chiral domain walls.