bluuebunny/crossref_metadata_2025 huggingface dataset:
Robust skyrmion mediated reversal of ferromagnetic nanodots of 20 nm lateral dimension with high Ms and observable DMI
Authors: Rajib Md Mahadi , Misba Walid Al , Bhattacharya Dhritiman , Atulasimha Jayasimha
Published: October 2021

Implementation of skyrmion based energy efficient and high-density data storage devices requires aggressive scaling of skyrmion size. Ferrimagnetic materials are considered to be a suitable platform for this purpose due to their low saturation magnetization (i.e. smaller stray field). However, this method of lowering the saturation magnetization and scaling the lateral size of skyrmions is only applicable where the skyrmions have a smaller lateral dimension compared to the hosting film. Here, we show by performing rigorous micromagnetic simulation that the size of skyrmions, which have lateral dimension comparable to their hosting nanodot can be scaled by increasing saturation magnetization. Also, when the lateral dimension of nanodot is reduced and thereby the skyrmion confined in it is downscaled, there remains a challenge in forming a stable skyrmion with experimentally observed Dzyaloshinskii–Moriya interaction (DMI) values since this interaction has to facilitate higher canting  per spin to complete a 360° rotation along the diameter. In our study, we found that skyrmions can be formed in 20 nm lateral dimension nanodots with high saturation magnetization (1.30–1.70 MA/m) and DMI values (~ 3 mJ/m2) that have been reported to date. This result could stimulate experiments on implementation of highly dense skyrmion devices. Additionally, using this, we show that voltage controlled magnetic anisotropy based switching mediated by an intermediate skyrmion state can be achieved in the soft layer of a ferromagnetic p-MTJ of lateral dimensions 20 nm with sub 1 fJ/bit energy in the presence of room temperature thermal noise with reasonable DMI ~ 3 mJ/m2.
Risk of acute atherosclerotic cardiovascular disease in patients with acute and chronic pancreatitis
Authors: Sung Li-Chin , Chang Chuen-Chau , Lin Chao-Shun , Yeh Chun-Chieh , Cherng Yih-Giun , Chen Ta-Liang , Liao Chien-Chang
Published: October 2021

The association between pancreatitis and acute myocardial infarction or stroke remains incompletely understood. This study aimed to evaluate the long-term risk of acute atherosclerotic cardiovascular disease (ASCVD) in people with acute and chronic pancreatitis. Using research database of Taiwan's National Health Insurance, we identified 2678 patients aged ≥ 20 years with newly diagnosed pancreatitis in 2000–2008. A cohort of 10,825 adults without pancreatitis was selected for comparison, with matching by age and sex. Both cohorts were followed from 2000 to the end of 2013, and incident acute ASCVD was identified during the follow-up period. Adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of acute ASCVD associated with pancreatitis were calculated. Compared with the comparison cohort, the adjusted HR of acute ASCVD were 1.76 (95% CI 1.47–2.12) and 3.42 (95% CI 1.69–6.94) for people with acute pancreatitis and chronic pancreatitis, respectively. A history of alcohol-related illness (HR 9.49, 95% CI 3.78–23.8), liver cirrhosis (HR 7.31, 95% CI 1.81–29.5), and diabetes (HR 6.89, 95% CI 2.18–21.8) may worsen the risk of acute ASCVD in patients with chronic pancreatitis. Compared with people had no pancreatitis, patients with acute pancreatitis who had alcohol-related illness (HR 4.66, 95% CI 3.24–6.70), liver cirrhosis (HR 4.44, 95% CI 3.05–6.47), and diabetes (HR 2.61, 95% CI 2.03–3.36) were at increased risk of acute ASCVD. However, the cumulative use of metformin was associated with a reduced risk of acute ASCVD in the acute pancreatitis cohort (HR 0.30, 95% CI 0.17–0.50). Compared with the control group, patients with acute or chronic pancreatitis were more likely to have an increased risk of acute ASCVD, while the use of metformin reduced the risk of acute ASCVD. Our findings warrant a survey and education on acute ASCVD for patients with acute and chronic pancreatitis.
Sublethal effects of bifenazate on biological traits and enzymatic properties in the Panonychus citri (Acari: Tetranychidae)
Authors: Wang Hongyan , Xin Tianrong , Wang Jing , Zou Zhiwen , Zhong Ling , Xia Bin
Published: October 2021

Panonychus citri, a major citrus pest. In pest management, bifenazate is a novel acaricide with high biological activity against red mites, such as Tetranychus urticae Koch. However, in the field, pests are frequently exposed to sublethal or lethal concentrations of pesticides. At present, its sublethal effects on P. citri have not been reported. Therefore, in order to investigate sublethal effect of bifenazate on biological traits and enzymatic properties of P. citri. The newly emerged females were treated with two concentrations of bifenazate: LC10 and LC30, the development and fecundity were observed. The results showed that female adult duration, fecundity, oviposition days, longevity were decrease compared with control, but pre-oviposition period was longer, net reproductive rate (R0), mean generation (T) were decreased, intrinsic rate of increase (rm), finite rate (λ) were decreased in LC30, however, doubling time was increased. Enzymatic tests showed that CAT, POD, CarE activities were higher in treatments than control. The SOD and GST activities were lower in LC30 than control and LC10, the CYP450 activity was decreased with the increasing concentrations. This study demonstrated that low lethal concentrations of bifenazate adversely affected life table parameters, enzymatic properties in P. citri. Therefore, bifenazate has the potential to control this pest.
A novel cell membrane-targeting fluorescent probe for imaging endogenous/exogenous formaldehyde in live cells and zebrafish
Authors: Sheng Wenlong , Zhang Xue , Yu Miaohui , Jin Meng , Li Ning , Sun Chen , Wang Lizhen , Xia Qing , Li Xiaobin , Zhang Yun , Zhu Baocun , Liu Kechun
Published: October 2021

We constructed a cell membrane-targeting fluorescent probe Mem-FA with high selectivity and sensitivity for distinguishing the source of formaldehyde in living cells and tracking endogenous formaldehyde in living cells and zebrafish.
Novel α-tocopherol–ferrocene conjugates for the specific delivery of transgenes in liver cancer cells under high serum conditions
Authors: Asfiya Rahmat , Maiti Bappa , Kamra Mohini , Karande Anjali Anoop , Bhattacharya Santanu
Published: October 2021

Selective liposomal gene transfection in liver cancer cells under high serum condition.
Supramolecular helices from helical building blocks via head-to-tail intermolecular interactions
Authors: Yan Xiaosheng , Weng Peimin , Shi Di , Jiang Yun-Bao
Published: October 2021

Helical building blocks can self-assemble into supramolecular helices via head-to-tail intermolecular interactions, wherein good propagation of helicity operates, exhibiting favourable homochiral elongation and functional helical channel structures.
Stability of adsorption of Mg and Na on sulfur-functionalized MXenes
Authors: Chaney G. , Çakır D. , Peeters F. M. , Ataca C.
Published: October 2021

In this work, we predict that the Ti2CS2 monolayer is appropriate as a Mg-ion battery electrode material.
Why are Zn-rich Zn–Mg nanoalloys optimal protective coatings against corrosion? A first-principles study of the initial stages of the oxidation process
Authors: Álvarez-Zapatero P. , Lebon A. , Aguilera del Toro R. H. , Aguado A. , Vega A.
Published: October 2021

Alloying with small amounts of Mg create a positive synergy between Zn and Mg that increases the reactivity to oxygen while reducing the stress induced on the cluster substrate, promoting the growth of the oxide crust whilst protecting the core.
Top-down fabrication of Ti doped BiVO4 nanosheets for efficient water oxidation under visible light
Authors: Peng Bei , Shi Yawen , Zhang Xin , Lv Peiwen
Published: October 2021

Ti dopant introduces surface oxygen vacancies for the reactive sites for the OER in a top-down fabricated 2D BiVO4 nanosheet.
Optical fiber sensors based on sol–gel materials: design, fabrication and application in concrete structures
Authors: Figueira Rita B. , de Almeida José M. , Ferreira Bárbara , Coelho Luís , Silva Carlos J. R.
Published: October 2021

This review provides an overview of the state-of-the-art of OFS based on sol–gel materials for diverse applications with particular emphasis on OFS for structural health monitoring of concrete structures.
Multifunctional NiFe2O4 nanoparticles for sodium-ion batteries, sensing, and photocatalysis
Authors: Patil S. B. , Patil Shivaraj B. , Deepa S. , Udayabhanu  , Nagaraju G. , Swamy B. E. Kumara
Published: October 2021

NiFe2O4 NPs synthesized by co-precipitation method exhibited excellent electrochemical properties towards sodium ion batteries and oxidation of uric acid. NiFe2O4 NPs also exhibited good catalytic activity for simultaneous degradation of multiple dyes.
Construction of a three-dimensional S,N co-doped ZIF-67 derivative assisted by PEDOT nanowires and its application in rechargeable Zn–air batteries
Authors: Xiang Wenjuan , Li Jing , Ma Jinfu , Sheng Zhilin , Lu Hui , Yang Shaolin
Published: October 2021

PEDOT nanowires were obtained before pyrolysis to inhibit structural collapse and anisotropic shrinkage of the ZIF-67 in the pyrolysis process, and S,N co-doping is realized at the same time. The synthesized Co/C@NS NWs exhibit excellent performance towards ORR and OER.
Modified biomimetic core–shell nanostructures enable long circulation and targeted delivery for cancer therapy
Authors: Zhang Yifan , Benassi Enrico , Shi Yue , Yue Xuanyu , Cui Lin , Yang Shengchao , Liu Zhiyong , Guo Xuhong
Published: October 2021

A “Trojan horse” strategy realizes long circulation and precise targeting of Bio-RBCm@MSN–DOX nanoparticles to efficiently kill tumor cells.
Microfluidic nanopaper based analytical device for colorimetric and naked eye determination of cholesterol using the color change of triangular silver nanoprisms
Authors: Shariati Sattar , Khayatian Gholamreza
Published: October 2021

A microfluidic nanopaper-based analytical device (μNPAD) has been prepared for the determination of cholesterol by using triangular silver nanoprisms (T-AgNPrs).
Predictions of attainable compositions of layered quaternary i-MAB phases and solid solution MAB phases
Authors: Dahlqvist Martin , Rosen Johanna
Published: October 2021

Theoretical predctions of possible MAB phase compositions for future synthesis.
Highly efficient copper halide scintillators for high-performance and dynamic X-ray imaging
Authors: Zhou Quan , Ren Jiwei , Xiao Jiawen , Lei Lin , Liao Feiyi , Di Haipeng , Wang Chao , Yang Lijun , Chen Qi , Yang Xiaofang , Zhao Yiying , Han Xiaodong
Published: October 2021

The β-Cs3Cu2Cl5 nanocrystals were developed as high-performance scintillators, which showed a PLQY of 94.6% and a radioluminescence light yield of ∼34000 photons per MeV. A high spatial resolution in the X-ray imaging results was demonstrated.
Locomotion of micromotors in paper chips
Authors: De Dios Andres Paula , Ramos-Docampo Miguel A. , Qian Xiaomin , Stingaciu Marian , Städler Brigitte
Published: October 2021

Micromotors exhibit size, density and surface modification dependent locomotion in different fibrous cellulose environments.
Supported Pt–Cu bimetallic catalysts: preparation and synergic effects in their catalytic oxidative degradation of aniline
Authors: Ding Qiuyue , Zhang Wumin , Zhu Yuanyuan , Wang Lu , Feng Xinyuan , Xi Yanyan , Lin Xufeng
Published: October 2021

An AC supported Pt–Cu catalyst prepared with a new methanal reduction method was found to be quite effective for catalytic Fenton oxidation of aniline in water. The Pt and Cu components showed a synergic effect for the catalytic process.
Correlation of grain orientations and the thickness of gradient MoS2 films
Authors: Chang Hui-Ping , Hofmann Mario , Hsieh Ya-Ping , Chen You-Sheng , Lin Jauyn Grace
Published: October 2021

Correlation of grain orientations, film thickness, and A1g/E12g ratios extracted from the Raman spectra of gradient MoS2.
Exploring the role of scaffolds in problem-based learning (PBL) in an undergraduate chemistry laboratory
Authors: Varadarajan Sujatha , Ladage Savita
Published: October 2021

The need for shifting the expository laboratory instruction style to inquiry-based approaches is widely acknowledged. Problem-based learning (PBL), one of the inquiry-based approaches, advocates students’ self-directed learning. The literature indicates that scaffolding students’ independent learning is necessary for a PBL environment. In our study, we provided scaffolds such as a precursor task, reading material, and structured group discussion to facilitate the planning of a PBL task on indigo dyeing wastewater treatment. In this paper, we describe how these three scaffolds integrated within the PBL style contributed to students’ learning as per the stages of Kolb's Experiential Learning Cycle (ELC). We analyzed the level of the abstract conceptualization stage of ELC through students’ experimental designs (EDs) of the PBL task. The results of the qualitative analysis of the scaffolded and un-scaffolded groups suggest that scaffolded students’ experimental design scores are higher. The qualitative results indicate that the structured group discussion influences the EDs planned by students more than the precursor task and the reading material. All three scaffolds help in the reflective learning and planning of executable EDs for a PBL task. The study indicates that students transitioning into the inquiry laboratory benefit from the inclusion of scaffolding.
CsPbBr3–CdS heterostructure: stabilizing perovskite nanocrystals for photocatalysis
Authors: Kipkorir Anthony , DuBose Jeffrey , Cho Junsang , Kamat Prashant V.
Published: October 2021

The insights into effective utilization of perovskite nanocrystals built around a CsPbBr3–CdS heterostructure pave the way towards their utilization in photocatalytic reduction and oxidation processes.
Radical–anion coupling through reagent design: hydroxylation of aryl halides
Authors: Greener Andrew J. , Ubysz Patrycja , Owens-Ward Will , Smith George , Ocaña Ivan , Whitwood Adrian C. , Chechik Victor , James Michael J.
Published: October 2021

The design and development of an oxime-based hydroxylation reagent, which can chemoselectively convert aryl halides (X = F, Cl, Br, I) into phenols under operationally simple, transition-metal-free conditions is described.
A high-performance lithiated silicon–sulfur battery enabled by fluorinated ether electrolytes
Authors: Zhang Leicheng , Zhao Chen , Lin Yanke , Wu Maochun , Zhao Tianshou
Published: October 2021

The newly developed fluorinated electrolyte enables the good cycling performance of lithiated silicon–sulfur batteries.
Bio-skin inspired 3D porous cellulose/AlPO4 nano-laminated film with structure-enhanced selective emission for all-day non-power cooling
Authors: Feng Shuangjiang , Zhou Yuming , Chen Xi , Shi Shengnan , Liu Chenghuan , Zhang Tao
Published: October 2021

Skin-inspired bio-structural PRC film with excellent solar reflectivity and selective emission has been obtained with the ultra-rapid solvent extraction strategy.
A confined thermal transformation strategy to synthesize single atom catalysts supported on nitrogen-doped mesoporous carbon nanospheres for selective hydrogenation
Authors: Tian Zhengbin , Wang Wenquan , Zheng Yan , Wang Guang-Hui
Published: October 2021

Pd single atoms supported on nitrogen-doped mesoporous carbon nanospheres (Pd1/NMCS) are prepared by a confined thermal transformation strategy, and show excellent performance for selective hydrogenation of quinoline to 1,2,3,4-tetrahydroquinoline.
A perylene diimide dimer-based electron transporting material with an A–D–A structure for efficient inverted perovskite solar cells
Authors: Fan Yunhao , Wu Fei , Liu Fan , Han Mengmeng , Chang Kai , Zhu Linna , Li Qianqian , Li Zhen
Published: October 2021

Through the combination of perylene diimide and triphenylamine moieties, a perovskite solar cell with DPT as the electronic transport material exhibited a PCE of 20.07%.
Digital Twin (DT) in Smart Energy Systems - Systematic Literature Review of DT as a growing solution for Energy Internet of the Things (EIoT)
Authors: Aghazadeh Ardebili Ali , Longo Antonella , Ficarella Antonio
Published: October 2021

In the industry 4.0 era, the Smart Energy System (SES) should be able to address the emerging challenges of digitization and socioeconomic/ecologic transition along with other critical entities of the society. However, because of the complexity of this system, both researchers and practitioners are seeking an agile and smart solution. The main motive of this review is to investigate the applications and implementation of Digital Twin (DT) in the provision of energy services. Research Questions (RQ) of this study include: RQ1: What are the applications of DT in SES and how effective is DT in that use case of EIoT? RQ2: Which issues of an SES can be addressed efficiently by using DT? Through answering the mentioned questions, the current study is heading to following objectives (O), O1: Describe the state of the art of DT in SES. O2: Develop a direction for energy 4.0 management through listing the applications, challenges and important factors of implementing DTs. O3: Provide a list of various approaches in employing DT in the scope of SES. The current study is a systematic literature review (SLR), based on SCOPUS, WOS and IEEE digital libraries. Two keywords (namely “Digital Twin” and “Energy Systems”) have been first used. To achieve the final list of articles, 2 levels of screening have been conducted. The first Screening was based on the relevance of the results concerning research objectives. The second screening was an abstract study. The exclusion/inclusion criteria in the abstract study were based on the research questions. The papers that have the potential of answering one of the research questions have been included. Since the implementation of DT is a rather new topic, both backward snowballing and forward snowballing strategies are implemented to finalize the article selection phase. 60 articles identified by searching through scientific databases and 11 articles have been appended to the list during the snowballing process. The results of the current review provide a managerial guideline for practitioners that are heading to utilize DT, along with an anthology of DT within SES scope to feed possible future studies.
Off-Design Modelling of ORC Turbines for Geothermal Application
Authors: Ungar Pietro , Özcan Zekeriya , Manfrida Giampaolo , Ekici Özgür , Talluri Lorenzo
Published: October 2021

In this study, turbine modelling of a geothermal sourced organic Rankine cycle (ORC) power plant is aimed. Thermodynamic model of the plant is constructed with the help of design and off-design plant data from an existing two-cycle power plant in southwestern Anatolia. Utilizing statistical analysis tools such as maximum likelihood estimation and probability distribution, plant variables are obtained within their standard deviations. Stodola curves and probability calculations demonstrate that both turbines are most likely to have two stages. Average losses are 2.3 MW and 1.2 MW from Turbine-I and Turbine-II respectively throughout the different seasons. After the determination of losses, overall turbine efficiencies demonstrate a reverse trend with increasing reduced mass flow rate. This may be associated with the increased choking of the turbine. Correlations estimate rather fixed efficiency values at off-design conditions (84% for Turbine-I and 77% for Turbine-II); that is an expected outcome since these correlations are influenced mainly by the design isentropic efficiency, which is a constant value. On the other hand, these correlations are most likely to be proposed for non-choking conditions which are invalid for off-design conditions of existing ORC turbines. Datapoint dispersion in Turbine-II does not demonstrate a strong correlation with physical constraints such as -pressure ratio and reduced mass flow rate- as it does for Turbine-I; this phenomenon may need further attention for future work.
Anonyme Geburt: Vertraulich und sicher
gebären
Authors: Selig Alexander
Published: October 2021

Frauen, die ein Kind erwarten, das sie nicht behalten möchten, sehen
sich in einer schwierigen Situation: Rechtlich gesehen dürfen sie
ihr Kind nicht einfach im Stich lassen. Babyklappen bieten ihnen eine
Möglichkeit, das Kind abzugeben. Mit der anonymen Geburt wurde ein
Verfahren geschaffen, bei dem diese Frauen in vertraulicher
Athmosphäre und dennoch medizinisch versorgt gebären
können.
Recognition of the internal situation of aircraft skin based on deep learning
Authors: Li Caizhi , Wei Xiaolong , Guo Hanyi , He Weifeng , Wu Xin , Xu Haojun , Liu Xinyu
Published: October 2021

The aircraft skin is an important component of the aircraft, and its integrity affects the flight performance and safety performance of the aircraft. Damage detection technology with ultrasonic nondestructive testing as the core has played an important role in aircraft skin damage detection. Due to the difficulty in aircraft skin detection, relying solely on the ultrasonic A-scan equipment has very low detection efficiency. The introduction of artificial intelligence can effectively improve the detection efficiency. This paper establishes the one-dimensional convolutional neural network and single shot multibox detector network, which is based on the SSD network and uses dilated convolution to improve the real-time tracking of the ultrasonic probe. At the same time, 1DCNN is introduced to classify the ultrasonic A-scan signal. Finally, the detection results of the two are combined to achieve the reflection of the internal conditions of the aircraft skin. After testing, the algorithm can identify skin simulation specimens, and its recognition accuracy is 96.5%, AP is 90.9%, and kappa is 0.996. Comparing the improved SSD network with networks such as SSD, YOLOv3, and Faster R-CNN, the results show that the improved network used in this paper is more excellent and effective. At the same time, the detection effects of four types of optimization algorithms and five learning rates are studied, and finally, the corresponding signal classification model adopts Adam and the learning rate of 0.0001 has the best effect.
Charge transport affected by energy level alignment in perovskite solar cells
Authors: Zhang Qiqi , Williams Kira , Tatum James , Han Fengxiang , Zhu Xianchun , Dai Qilin
Published: October 2021

The electron transport layer is very critical to the device performance in perovskite solar cells. In this work, we use a solution-processed method to prepare uniform Zn2SnO4, SnO2, and ZnO thin films using very similar experimental conditions. Perovskite solar cells (PSCs) based on different electron transporting layers are fabricated and compared. Three different energy level alignments produced by Zn2SnO4, SnO2, and ZnO are realized by the corresponding bandgap structures. Meanwhile, energy loss and driving force caused by the three materials are two important factors that affect charge transport. We use this system to test which factor is dominant in terms of charge transport and device performance. The optimal efficiency of PSCs based on Zn2SnO4 is 16.9%, which is much higher than SnO2 (13.4%) and ZnO (5.9%) prepared by a similar method. Therefore, we attribute the high efficiency to the reduced energy loss during charge transfer from the perovskite layer to Zn2SnO4. The large driving force of the PSC based on SnO2 and ZnO cannot achieve high efficiency. Therefore, energy loss is a dominant factor in the presence of a driving force. This work presents an understanding of the efficient charge transfer in the devices, which proposes a direction to optimize charge transfer in optoelectronic devices toward high efficiency.
Critical dynamics and phase transition of a strongly interacting warm spin gas
Authors: Horowicz Yahel , Katz Or , Raz Oren , Firstenberg Ofer
Published: October 2021

Significance

Investigation of new phases of matter and, generally, the study of correlated states of many particles are at the frontier of interdisciplinary physical research. Ordered phases are extensively studied in condensed matter and atomic physics, especially in low-temperature spin systems. However, at ambient temperature, spin gases are conceived disordered, with high entropy and weak or random many-body interactions. In this work, we discover a new magnetic phase of cesium vapor at room temperature. Near the phase boundary, we observe a 100-fold enhancement of the spins’ response time. Our findings open exciting avenues to precision quantum sensing, out-of-equilibrium magnetic simulations with many-body correlations, and the realization of Ising computation at ambient conditions.
Thermally stratified flow of hybrid nanofluids with radiative heat transport and slip mechanism: multiple solutions
Authors: Saif Rai Sajjad , Hashim  , Zaman Maria , Ayaz Muhammad
Published: October 2021

Research on flow and heat transfer of hybrid nanofluids has gained great significance due to their efficient heat transfer capabilities. In fact, hybrid nanofluids are a novel type of fluid designed to enhance heat transfer rate and have a wide range of engineering and industrial applications. Motivated by this evolution, a theoretical analysis is performed to explore the flow and heat transport characteristics of Cu/Al2O3 hybrid nanofluids driven by a stretching/shrinking geometry. Further, this work focuses on the physical impacts of thermal stratification as well as thermal radiation during hybrid nanofluid flow in the presence of a velocity slip mechanism. The mathematical modelling incorporates the basic conservation laws and Boussinesq approximations. This formulation gives a system of governing partial differential equations which are later reduced into ordinary differential equations via dimensionless variables. An efficient numerical solver, known as bvp4c in MATLAB, is utilized to acquire multiple (upper and lower) numerical solutions in the case of shrinking flow. The computed results are presented in the form of flow and temperature fields. The most significant findings acquired from the current study suggest that multiple solutions exist only in the case of a shrinking surface until a critical/turning point. Moreover, solutions are unavailable beyond this turning point, indicating flow separation. It is found that the fluid temperature has been impressively enhanced by a higher nanoparticle volume fraction for both solutions. On the other hand, the outcomes disclose that the wall shear stress is reduced with higher magnetic field in the case of the second solution. The simulation outcomes are in excellent agreement with earlier research, with a relative error of less than 1%.
Transition to chaos in lid–driven square cavity flow*
Authors: Wang Tao , Liu Tiegang
Published: October 2021

To date, there are very few studies on the transition beyond second Hopf bifurcation in a lid–driven square cavity, due to the difficulties in theoretical analysis and numerical simulations. In this paper, we study the characteristics of the third Hopf bifurcation in a driven square cavity by applying a consistent fourth-order compact finite difference scheme rectently developed by us. We numerically identify the critical Reynolds number of the third Hopf bifurcation located in the interval of (13944.7021,13946.5333) by the method of bisection. Through Fourier analysis, it is discovered that the flow becomes chaotic with a characteristic of period-doubling bifurcation when the Reynolds number is beyond the third bifurcation critical interval. Nonlinear time series analysis further ascertains the flow chaotic behaviors via the phase diagram, Kolmogorov entropy and maximal Lyapunov exponent. The phase diagram changes interestingly from a closed curve with self-intersection to an unclosed curve and the attractor eventually becomes strange when the flow becomes chaotic.
Effect of Cu doping on the secondary electron yield of carbon films on Ag-plated aluminum alloy
Authors: Hu Tiancun , Zhu Shukai , Zhao Yanan , Sun Xuan , Yang Jing , He Yun , Wang Xinbo , Bai Chunjiang , Bai He , Wei Huan , Cao Meng , Hu Zhongqiang , Liu Ming , Cui Wanzhao
Published: October 2021

Reducing the secondary electron yield (SEY) of Ag-plated aluminum alloy is important for high-power microwave components. In this work, Cu doped carbon films are prepared and the secondary electron emission characteristics are studied systematically. The secondary electron coefficient δ
max of carbon films increases with the Cu contents increasing at first, and then decreases to 1.53 at a high doping ratio of 0.645. From the viewpoint of surface structure, the higher the content of Cu is, the rougher the surface is, since more cluster particles appear on the surface due to the small solid solubility of Cu in the amorphous carbon network. However, from viewpoint of the electronic structure, the reduction of the sp2 hybrid bonds will increase the SEY effect as the content of Cu increases, due to the decreasing probability of collision with free electrons. Thus, the two mechanisms would compete and coexist to affect the SEY characteristics in Cu doped carbon films.
Theoretical predictions on α-decay properties of some unknown neutron-deficient actinide nuclei using machine learning *
Authors: Yuan Ziyi , Bai Dong , Ren Zhongzhou , Wang Zhen
Published: October 2021

Neutron-deficient actinide nuclei provide a valuable window to probe heavy nuclear systems with large proton-neutron ratios. In recent years, several new neutron-deficient Uranium and Neptunium isotopes have been observed using α-decay spectroscopy [Z. Y. Zhang et al., Phys. Rev. Lett. 122, 192503 (2019); L. Ma et al., Phys. Rev. Lett. 125, 032502 (2020); Z. Y. Zhang et al., Phys. Rev. Lett. 126, 152502 (2021)]. In spite of these achievements, some neutron-deficient key nuclei in this mass region are still unknown in experiments. Machine learning algorithms have been applied successfully in different branches of modern physics. It is interesting to explore their applicability in α-decay studies. In this work, we propose a new model to predict the α-decay energies and half-lives within the framework based on a machine learning algorithm called the Gaussian process. We first calculate the α-decay properties of the new actinide nucleus

. The theoretical results show good agreement with the latest experimental data, which demonstrates the reliability of our model. We further use the model to predict the α-decay properties of some unknown neutron-deficient actinide isotopes and compare the results with traditional models. The results may be useful for future synthesis and identification of these unknown isotopes.
Neutronics for the GEMINI+ HTGR
Authors: Kuijper J C , Muszynski D
Published: October 2021

Literally at the heart of the Euratom Horizon 2020 project GEMINI+ are the core neutronics (design) calculations. For these calculations on a relatively small (180 MWth) prismatic HTGR with cylindrical core, the 3-D monte-carlo particle transport and depletion code SERPENT version 2 (VTT, Finland) was selected, the main reasons being the flexibility and versatility of this code. This enables the modelling of all relevant details of the reactor without unnecessary approximations. A particularly useful feature of the SERPENT code is the multiphysics input capability. This allows to map a temperature field over the defined geometry, enabling the calculation of converged power and temperature distribution by means of iteration and data exchange between SERPENT and a (steady-state) thermal- hydraulics code. In this particular case the SPECTRA code (NRG, The Netherlands) was used to provide the temperature distribution. 4 to 5 iterations are sufficient to reach simultaneously converged distributions for power and temperature. The paper gives an overview of the performed analyses for the current (June 2020) design of the GEMINI+ HTGR, and results thereof. Neutronics features seem quite promising, but further improvements and therefore further investigations would be desirable.
Wind-blown dust and its impacts on particulate matter pollution in Northern China: current and future scenarios
Authors: Liu Song , Xing Jia , Sahu Shovan Kumar , Liu Xiliang , Liu Shuchang , Jiang Yueqi , Zhang Hongliang , Li Siwei , Ding Dian , Chang Xing , Wang Shuxiao
Published: October 2021

Northern China experienced two intense dust storms in March 2021, leading to reduced visibility and excessive particulate pollution. Understanding the cause of such extreme phenomena is important for further prevention. This study successfully reproduced the extreme dust storms using the Community Multiscale Air Quality model with refined bulk density of different soil types and improved spatial resolution. The wind-blown PM2.5 and PM10 are estimated to be around 15 and 120 μg m−3 in dust source areas (equal 9.6% and 31.0% in average of China), resulting in 1.1 and 2.0 times increases in PM2.5 and PM10 concentrations in populated regions of the Middle Yellow River Basin and the Beijing-Tianjin-Hebei area. The critical threshold friction velocity is the key parameter to judge whether wind-blown dust occurs. Dust flux is sensitive to the bulk soil density (increased by 4.2% and 12.6% for PM2.5 and PM10 after refined soil bulk density) and resolution (increased by 13.5% and 3.5% for PM2.5 and PM10 from 27 km to 9 km). Such results demonstrated the strong correlation between wind speed, frequency, and intensity of dust phenomena from 2013 to 2021. The wind speed can be further enhanced in dust source areas even in the context of a decline in the national average, leading to more frequent and persistent dust storms in March 2050. Only relying on coordinated emission reductions to mitigate climate change, wind-blown dust in northern China still poses considerable potential risks to air quality. Urgent actions should also be taken to improve land-use and land-cover to reduce the area of dust sources.
Photoluminescence enhancement in multilayered MoSe2 nanostructures obtained by local anodic oxidation
Authors: Borodin Bogdan R , Benimetskiy Fedor A , Davydov Valery Yu , Smirnov Alexander N , Eliseyev Ilya A , Alekseev Prokhor A
Published: October 2021

Monolayers of transition metal dichalcogenides (TMDCs) exhibit attractive properties and are promising for fabricating photonic and optoelectronic devices, while bulk multilayered structures based on the same materials only recently has revealed many properties useful for nanophotonics. In this regard, the combination of monolayer and multilayer properties in one device (on a single flake) is an important and fruitful task that needs to be solved. In this work, we demonstrate the use of local anodic oxidation to improve the optical properties of multilayer MoSe2 flakes on a gold-covered substrate. Using this method, we fabricated nanostructures demonstrating extraordinarily enhanced photoluminescence (PL), with an intensity up to three orders of magnitude compared to that of the original structure. Low-frequency Raman spectroscopy showed that the nature of this PL enhancement is that the bindings between the layers inside the nanostructures are severely disrupted. This means that the nanostructures consist of quasi-monolayers, which is in good agreement with the intensity and the position of PL peak. Here, we also propose a mechanism of forming these quasi-monolayers. Therefore, this method allows using multilayer TMDC flakes on a conductive substrate to fabricate areas with quasi-monolayer optical properties, exhibiting an enhanced PL intensity.
Study on hardness prediction and parameter optimization for carburizing and quenching: an approach based on FEM, ANN and GA
Authors: Liang Ruijun , Wang Zhiqiang , Yang Shuying , Chen Weifang
Published: October 2021

A proper hardening depth is critical to the load-bearing capacity of a part, and heat treatment, including carburizing and quenching, can highly determine the hardness distribution in the part’s surface after manufacturing. This paper proposes a ‘hardness prediction and parameter optimization’ approach that deploys the finite element method (FEM), the artificial neural network (ANN), and the Genetic Algorithm (GA), to describe the relationships between the carburizing/quenching parameters and the hardening depths and conversely to determine the optimized parameters for a given hardening depth. First, the numerical models for carburizing, quenching, and the hardness field are built respectively. And based on these models, the finite element simulation model is designed to predict the carbon content, the microstructure and the hardness of the part. A BP network is then trained by using the data obtained from the finite element simulation, and the model between the carburizing/quenching parameters and the hardening depths on part is established. The optimization model for the carburizing/quenching parameters is finally established through GA, which can determine the optimized parameters for a given hardening depth. The effectiveness of the ‘prediction-optimization’ approach is verified by a series of experiments. The hardening depth predicted by the proposed approach holds a 10% relative error from that measured in the carburizing and quenching experiment. And the optimized parameters for the heat treatment process can work as a meaningful reference for the heat treatment.
Molten pool structure and temperature flow behavior of green-laser powder bed fusion pure copper
Authors: Lu Pan , Cheng-Lin Zhang , Tong Liu , Xin-Yu Liu , Jiang-Lin Liu , Shun Liu , Wen-Hao Wang , Heng-Hua Zhang
Published: October 2021

Additive Manufacturing(AM) is an advanced direct-manufacturing technology, based on the discrete-stacking principle. Laser Powder Bed Fusion (L-PBF) is one of the most promising technologies in the field of metal AM, with the characteristics of fabricating parts with complex shapes directly. For L-PBF equipment , the core device is lasers, and almost all L-PBF printers are currently equipped with infrared laser. However, due to too low absorption rate of the pure copper surface to infrared laser and high thermal conductivity between pure copper, it is extremely challenging to fabricate pure copper by traditional infrared-laser powder bed fusion(IR L-PFB). In this work, green-laser was applied to replace traditional infrared laser during L-PBF process, molten pool structure and temperature flow behavior of Green-Laser powder bed additive manufacturing pure copper was studied by mesoscopic simulation. Here we show that green-laser greatly improved the absorption rate of the pure copper surface, and the result showed that with lower cost laser process parameters (lower laser power 300W and larger hatching space 0.08 mm), pure copper parts with smoother surface, no-remelting and no obvious defects could be fabricated successfully.
On the stability of small-scale ballooning modes in axisymmetric mirror traps
Authors: KOTELNIKOV Igor , LIZUNOV Andrej , ZENG Qiusun
Published: October 2021

It is shown that a steepening of the radial plasma pressure profile leads to a decrease in the critical value of beta, above which, small-scale balloon-type perturbations in a mirror trap become unstable. This may mean that small-scale ballooning instability leads to a smoothing of the radial plasma profile. The critical beta values for the real magnetic field of the gas-dynamic trap and various plasma pressure radial profiles was also calculated. For a plasma with a parabolic profile critical beta is evaluated at the level of 0.72. A previous theoretical prediction for this trap was almost two times lower than maximal beta 0.6 achieved experimentally.
Kuramoto-model-based data classification using the synchronization dynamics of uniform-mode spin Hall nano-oscillators
Authors: Garg Neha , Hemadri Bhotla Sri Vasudha , Muduli Pranaba Kishor , Bhowmik Debanjan
Published: October 2021

Oscillator-based data-classification schemes have been proposed recently using the Kuramoto model, which tries to capture the synchronization behavior of coupled oscillators without considering the underlying physics of the oscillation and the coupling. In this paper, we propose the hardware implementation of a Kuramoto-model-based data-classification scheme through an array of dipole-coupled uniform-mode spin Hall nano-oscillators (SHNOs). Using micromagnetic simulations, which capture the underlying physics of operation of the SHNOs, we first study the variation of synchronization range between two uniform-mode SHNOs as a function of the physical distance between them. Thus we correlate the coupling constant in the Kuramoto model with the dipole-coupling strength between two SHNOs, which our micromagnetic simulation takes into account. Next, we generate the synchronization map for the two-input–two-output dipole-coupled uniform-mode SHNO system through micromagnetics and show that it matches with the one predicted by the Kuramoto model. Thus, we demonstrate here that the synchronization behavior of SHNOs obtained from micromagnetics-based modeling is consistent with that obtained from the Kuramoto model, which ignores the underlying physics of the SHNOs. This suggests that the Kuramoto-model-based data classification scheme can indeed be implemented physically on an array of SHNOs. To verify our claim, we show, through micromagnetic simulation, binary classification of data from a popular machine-learning data set (Fisher’s Iris data set) using an array of uniform-mode SHNOs.
Weighted Littlewood–Paley inequality for arbitrary rectangles in ℝ²
Authors: Borovitskiy V.
Published: October 2021

Weighted counterparts of the one-sided Littlewood–Paley inequalities for arbitrary rectangles in

R

2

\mathbb {R}^2

are proved.

For a partition

I

\mathcal {I}

of the plane

R

2

\mathbb {R}^2

into rectangles with sides parallel to coordinate axes and a weight

w
(

⋅

,

⋅

)

w(\,\cdot \,, \,\cdot \,)

satisfying the two-parameter Muckenhoupt condition

A

p

/

2

A_{p/2}

for

2
>
p
>
∞

2 > p > \infty

, the following inequality holds:
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="c Subscript p comma w Baseline double-vertical-bar left-brace upper M Subscript upper I Baseline f right-brace Subscript upper I element-of script upper I Baseline double-vertical-bar Subscript upper L Sub Subscript w Sub Superscript p Subscript left-parenthesis l squared right-parenthesis Baseline less-than-or-equal-to double-vertical-bar f double-vertical-bar Subscript upper L Sub Subscript w Sub Superscript p Subscript Baseline comma">

c

p
,
w

‖
{

M
I

f

}

I
∈

I

‖

L
w
p

(

l
2

)

≤
‖
f

‖

L
w
p

,

\begin{equation*} c_{p, w}\lVert \{M_I f\}_{I \in \mathcal {I}} \rVert _{L^p_w(l^2)} \leq \lVert f \rVert _{L_w^p} , \end{equation*}

where the symbols

M
I

f

^

=

f
^

χ

I

\widehat {M_I f} = \widehat {f} \chi _{I}

denote the corresponding Fourier multipliers.

For

I

\mathcal {I}

as above,

p
p

in the range

0
>
p
>
2

0 > p > 2

, and weights

w
w

satisfying a dual condition 

α

r
(
p
)

\alpha _{r(p)}

, the following inequality holds
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="double-vertical-bar sigma-summation Underscript upper I element-of script upper I Endscripts f Subscript upper I Baseline double-vertical-bar Subscript upper L Sub Subscript w Sub Superscript p Subscript Baseline less-than-or-equal-to upper C Subscript p comma w Baseline double-vertical-bar left-brace f Subscript upper I Baseline right-brace Subscript upper I element-of script upper I Baseline double-vertical-bar Subscript upper L Sub Subscript w Sub Superscript p Subscript left-parenthesis l squared right-parenthesis Baseline comma where s u p p ModifyingAbove f Subscript upper I Baseline With caret subset-of-or-equal-to upper I for upper I element-of script upper I period">

‖

∑

I
∈

I

f
I

‖

L
w
p

≤

C

p
,
w

‖

{

f
I

}

I
∈

I

‖

L
w
p

(

l
2

)

,
 where 
supp
⁡

f
I

^

⊆
I
 for 
I
∈

I

.

\begin{equation*} \Big \|{\sum }_{I \in \mathcal {I}} f_I\Big \|_{L^p_w} \leq C_{p, w} \big \| \left \{ f_I \right \}_{I \in \mathcal {I}} \big \|_{L^p_w(l^2)} , \text { where } \operatorname {supp}{\widehat {f_I}} \subseteq I \text { for } I \in \mathcal {I}. \end{equation*}

The proof is based on the theory of two-parameter singular integral operators on Hardy spaces developed by R. Fefferman and some of its more recent weighted generalizations. The former and the latter inequalities are extensions to the weighted setting, respectively, for Journe’s result of 1985 and Osipov’s result of 2010.
Impact of vaccination on the spread of SARS-CoV-2 infection in north-east Italy nursing homes. A propensity score and risk analysis
Authors: Pierobon Silvia , Braggion Marco , Fedeli Ugo , Nordio Maurizio , Basso Cristina , Zorzi Manuel
Published: October 2021

Background

In the Veneto Region, 421,000 coronavirus 2019 disease (COVID-19) cases and 11,000 deaths have been reported since 21 February 2020. The pandemic spread particularly in nursing homes (NH).

Objective

This study estimated the impact of SARS-CoV-2 infection among NH residents, focusing on the risk of hospitalisation and death due to COVID-19 compared with the general older population. It also provided evidence of risk changes over time.

Methods

Older people, resident in Veneto, were enrolled from the regional registry of the population. We collected also information about demographic characteristics, chronic diseases, COVID-19 positivity, NH institutionalization, hospitalisation and date of death. Patients were assigned to NH or non-NH residents groups through a propensity score 1:1 matching. The follow-up period was defined as 21 February 2020 – 3 May 2021 and then divided into three waves. Risk ratios (RRs) and 95% confidence interval were estimated by using Poisson models with robust estimation of variance.

Results

NH residents showed a higher risk of COVID-19 infection (RR = 6.28; 6.03–6.54), hospitalisation for COVID-19 (RR = 2.20; 2.05–2.36) and death with COVID-19 (RR = 6.07; 5.58–6.61).

Conclusion

NH residents shared common spaces with other patients and healthcare professionals and were more exposed to infections. Nonetheless, in Italy from late December 2020 to May 2021, 95% of NH residents and their healthcare professionals received at least one vaccine dose and RRs for all outcomes decreased in NH.
Are we allowed to visit now? Concerns and issues surrounding vaccination and infection risks in UK care homes during COVID-19
Authors: Giebel Clarissa , Hanna Kerry , Cannon Jacqueline , Marlow Paul , Tetlow Hilary , Mason Stephen , Shenton Justine , Rajagopal Manoj , Gabbay Mark
Published: October 2021

Background

vaccination uptake in the UK and increased care home testing are likely affecting care home visitation. With scant scientific evidence to date, the aim of this longitudinal qualitative study was to explore the impact of both (vaccination and testing) on the conduct and experiences of care home visits.

Methods

family carers of care home residents with dementia and care home staff from across the UK took part in baseline (October/November 2020) and follow-up interviews (March 2021). Public advisers were involved in all elements of the research. Data were analysed using thematic analysis.

Results

across 62 baseline and follow-up interviews with family carers (n = 26; 11) and care home staff (n = 16; 9), five core themes were developed: delayed and inconsistent offers of face-to-face visits; procedures and facilitation of visits; variable uptake of the COVID-19 vaccine; misinformation, education and free choice; frustration and anger among family carers. The variable uptake in staff, compared to family carers, was a key factor seemingly influencing visitation, with a lack of clear guidance leading care homes to implement infection control measures and visitation rights differently.

Conclusions

we make five recommendations in this paper to enable improved care home visitation in the ongoing, and in future, pandemics. Visits need to be enabled and any changes to visiting rights must be used as a last resort, reviewed regularly in consultation with residents and carers and restored as soon as possible as a top priority, whilst more education needs to be provided surrounding vaccination for care home staff.