bluuebunny/crossref_metadata_2025 huggingface dataset:
A novel transformerless high step‐Up DC‐DC converter with active switched‐inductor and quasi‐Z‐source network
Authors: Zhao Jiawei , Chen Daolian , Jiang Jiahui
Published: May 2021

Conventional dc–dc boost converters have limited boosting capabilities, and the main switching device may suffer relatively high voltage stress and current stress. A novel transformerless dc‐dc boost converter is proposed in this paper. The proposed topology, which combines the traditional active switch‐inductor and quasi‐Z‐source network, can increase the voltage gain without limiting the duty cycle or increasing the voltage and current stresses of the power switches. The detailed analysis including working principles, steady‐state characteristics, non‐ideal element analysis and a comprehensive comparison is also presented in this paper. To verify the proposed converter's performance, a prototype circuit with 20–30 V input voltage, 200 V output voltage, and 200 W output power is implemented in the laboratory. Experiment results confirm the theoretical analysis and advantages of the proposed converter.
Research on Integrated Energy Simulation System of Distribution Network
Authors: Yu Peng , Wang Yuejiao , Sun Hao , Li Mengyang , Li Rong , Sun Shumin
Published: May 2021

This article discussed multiple energy flow simulation technology based on the research status of integrated community energy system. Under the unified platform architecture, simulation, planning, optimization, and analysis of distribution multiple energy flow are realized. According to the idea of three cascades of energy utilization, the modeling of equipment in various professional fields is completed under unified software architecture, and the simulation system is finally developed. The system is built with plug-in software, which is open and extensible. The simulation system developed in this paper can be used in the simulation of distribution integrated energy system to realize the interaction between energy flow and information flow.
Research on Dynamic Braking Torque Test Method of Brake Motor
Authors: Huang Zheng-qiu , Li Guo-feng , Tong Yao-ting , Ouyang Wei-ping
Published: May 2021

Through the brief introduction of the working principle of the brake motor, combined with the theoretical analysis of the brake motor dynamic brake torque test method (directtest method and indirect test method), it is concluded that the selection of the test method is closely related. According to the sensor type, installation position, test range and accuracy requirements. The differences between direct measurement method and indirect measurement method are compared, their respective measurement methods are introduced, and their advantages and disadvantages are summarized. According to the test requirements, the appropriate test method can be selected, and the direct test method and indirect test method can be selected at the same time, to ensure the safety and stability of product
Research on Virtual Power Plant Optimal Scheduling Based on TOU Electricity Price
Authors: Liu Dunnan , Gao Yuan , Zhang Tingting , Dong Zhixin , Huang Haiyu , Wang Chunming , Xi Shaolian
Published: May 2021

The power supply in many provinces is in short supply during peak load period, and the largescale entry of new energy into the grid brings new problems to the safety and economic operation of the grid. Under the mechanism of time-of-use electricity price, the virtual power plant participates in the grid dispatching by integrating distributed new energy and demand-side resources, which can effectively participate in the peak load clipping and valley filling of the grid and suppress the load fluctuation of the grid. This paper builds a VPP economic optimization scheduling model based on TOU electricity price, and uses particle swarm optimization algorithm to get the output of each energy source of VPP. The simulation results show that the model is reasonable and economical.
Nexus between residential electricity consumption and household characteristics: heterogeneous urban and rural panel evidences from North China
Authors: Liang Mingliang , Li Wenxuan , Ji Jie , Liu Lili , Zhang Shiying , Zhao Huiru , Guo Sen
Published: May 2021

With the growth of residential electricity consumption and the development of power energy conservation, exploring the factors that affect residential electricity consumption is of great significance for promoting the sustainable development of the regional economy-power system. This paper examines the influencing factors of residential electricity consumption according to the data in 6 provinces in North China over 2008-2018, and two panels named urban panel and rural panel are constructed. Three conventional influencing factors are selected in this paper, namely, population (POP), per capita disposable income (DI) and per capita consumption expenditure (PCCE). Furthermore, considering that household characteristics have an impact on residential electricity consumption, this paper adds the number of household appliances (HA) and the per capita housing area (LS) into the factor set. Heterogeneous panel analysis techniques are applied to achieve the analysis, finding that household characteristics have significant impacts on electricity consumption of urban and rural residents, and the impact on electricity consumption of urban residents is greater than that on rural residents. Based on the empirical results, this paper puts forward several policy recommendations to effectively improve the residential electricity consumption and reduce the gap between urban and rural residential electricity consumption.
Decision Analysis of E-commerce Closed-loop Supply Chain with Different Recycling Modes
Authors: Liu Sijia , Huang Yanting
Published: May 2021

According to an e-commerce closed-loop supply chain dominated by manufacturers, which is composed of manufacturers and e-commerce platforms, divided into three different recovery mode: manufacturers recycling mode alone, electric business platform recycling mode alone, and manufacturers and electric business platform mixed mode, using the game theory to solve, compares three closed-loop supply chains found: (1)When the recycling price sensitivity is high, the optimal strategy of the manufacturer is the manufacturers recycling mode alone; when the price sensitivity of recycling is low, the manufacturer’s best strategy is the independent recycling mode of the e-commerce platform. No matter how sensitive the recycling price is, the profits of the manufacturer under the mixed recycling mode are always lower than those under the other two recycling modes. (2) When the recycling price sensitivity is high, the optimal strategy of the electric business platform is the mixed recycling mode; when the price sensitivity of recycling is low, the optimal solution of the electric business platform is the independent recycling mode of the electric business platform. (3) When the recovery price sensitivity is low, the best strategy of both is the separate recycling mode of the electric business platform.
Research on Real Estate Information System of the Real Estate Market Based on Big Data Technology
Authors: Li Benli
Published: May 2021

This article analyzes and studies the importance of establishing a real estate information system in the real estate market. The research content of this article includes improving the efficiency of data utilization, formulating the important support of marketing strategy, and the inevitable trend of marketing system reform. The author studies the system technical route analysis, functional module design, logical hierarchical structure design, overall database design, data collection and storage method design, system key technology application, etc. The purpose of this article is to improve the applicability of information systems to regional development and to enhance the use value of big data technology itself.
Research on Construction Risk Management of Underground Engineering Based on AHP-Fuzzy Comprehensive Evaluation Method
Authors: Han Zhichao , Zhu Jun , Wang Jianduo
Published: May 2021

In order to strengthen the construction risk management of underground engineering projects, reduce the probability of accidents, and ensure that the underground engineering completes the construction tasks on schedule, the article relies on a certain subway engineering project to carry out research from the aspects of risk identification, risk factor analysis, and risk factor evaluation. The article adopts analytic hierarchy process and fuzzy comprehensive evaluation method to carry out risk factor evaluation weight analysis and risk system evaluation in the construction process, and then realize reasonable prediction and evaluation of construction risk factors. Finally, this essay sorts out the prevention and control measures of underground engineering construction risk management from five aspects of personnel, machinery, management, environment and technology, and then provides auxiliary decision-making for underground engineering construction risk management.
Research on ecological restoration of rural landscape based on environmental value-added
Authors: Wan Ajun , Qi Xiaolei , Tu Runqiu
Published: May 2021

Reasonable planning of green space can effectively play the urban ecosystem service function and promote the sustainable development of rural areas. Taking LiuTian village in Shaanxi Province as an example, based on the analysis of rural landscape pattern, this paper explores the landscape comprehensive evaluation and planning ideas based on environmental value-added. The research results provide reference for the landscape construction and planning of the same type of villages in Guanzhong area of Shaanxi Province, and have good application prospects.
Research on Modularization and Association of Elderly Care Services in Big Data Environment
Authors: Zhao Yan
Published: May 2021

At this stage, China is in the stage of building a well-off society in an all-round way, and the application of big data has positive significance for the grasp of China’s national conditions and the laws of scientific development. At the same time, big data applications can also provide support for the development of the elderly care service industry. This article summarizes the modular content of elderly care services based on previous work experience. The author discusses the data association analysis of distributed elderly care services in a big data environment from four aspects: the construction of distributed association classifiers, the incremental mining of association classifiers based on constraints, the running process of the distributed association classifier model, and the evaluation of actual elderly care services.
The Analysis of Potential Residential Area/Center Based on Residents’ Travel Behaviour and Planned Metro Stations
Authors: Liu Lu , Song Yi , Li Peng
Published: May 2021

Metro is of vital importance in public transportation system. Recent studies have examined the influence of metro systems by various methodologies. However, few of them has focused on the stations which are planned to be built or still being built. Therefore, this study intends to evaluate the future metro stations and map the potential urban residential center, based on analyzing the metro card data of the existing metro systems. Based on a case study in Shenzhen, China, we identified 21 residential hot stations and 13 working hot stations. Also, the results indicate that most passengers have a travel length between 5-14 stops, while each residential center has its specific working center. Moreover, when the housing price decrease 1598.3 RMB per square meters, residents may be willing to move to a place with one more stop commuting time. Finally, based on two criteria established by the riding behavior, 67 new stations are found to have the chance to be new residential centers in the city. The strategy proposed in this study can help urban planners to understand the possible influences of new metro stations and assist them to do the planning work in a more appropriate way.
The City as a Socio-economic and Natural System
Authors: Todorova Stela , Haralampiev Kaloyan , Parzhanova Aneliya
Published: May 2021

The modern city is increasingly seen as a socio-economic and natural system - they must be seen as complex entities. They differ in their development and size. Their identity, though rooted in history, is constantly changing. Over time they have undergone evolution caused by new needs. The modern city is a mirror of socio-economic problems, on the one hand. When exploring the city, it is necessary to apply a holistic approach and consider it as a system. The aim of this study is to develop a complex indicator for urban development which requires the application of a methodology for normalization, categorization and aggregation of data. The obtained result gives a concrete assessment of the development of the city in numerical expression on the basis of complex criteria, which allows adequate and clear comparison between the cities.
Optimal policies for a deterministic continuous-time inventory model with several suppliers: a hyper-generalized (s,S) policy
Authors: Benkherouf Lakdere , Gilding Brian H.
Published: May 2021

A deterministic continuous-time continuous-state inventory model is studied. In the absence of intervention, the level of stock evolves by a process governed by a differential equation. The inventory level is monitored continuously, and can be adjusted upwards at any time. The decision maker can order from several suppliers, each of which charges a different ordering and purchasing cost. The problem of selecting the supplier and the size of the order to minimize the total inventory cost over an infinite planning horizon is formulated as the solution of a quasi-variational inequality (QVI). It is shown that the QVI has a unique solution. This corresponds to a generalized (s,S) policy under amenable conditions, which have been characterized in an earlier work by the present authors. Under the complementary conditions a new type of optimal control policy emerges. This leads to the concept of a hyper-generalized (s,S) policy. The theory behind a policy of this type is exposed.
Impact of cutting parameters on machining of Ti-6Al-4V alloy: an experimental and FEM approach
Authors: Gobivel Kathirvel , Vijaysekar Krishnaraju Srinivasaraju , Prabhakaran Gopalakrishnan
Published: May 2021

Titanium alloys are used as an aerospace material due to their inherent properties such as high strength to weight ratio, corrosion, and fracture resistance. However, the low conductivity and reactivity towards plastic deformation causes these materials to be difficult to cut category. The prediction of various parameters like chip formation and actual cutting forces are important factors for better machinability which involves lot of resources. To overcome such issues, this work proposes three-dimensional FE approach to simulate the machinability behavior of Ti-6Al-4V especially on conventional turning. The impact of cutting speed and feed rate on the cutting force, thrust force, feed force and surface roughness were analyzed experimentally for various conditions. The predicted machining forces showed strong correlation with the experimental results and the effective von mises stress were examined.
Woran starben Dr. Carl Lüderitz (1854–1930) und seine Vor- und Nachfahren?
Authors: Enck Paul , Mai Gunther , Frieling Thomas , Schemann Michael
Published: May 2021

Diagnostik allein auf der Basis von Symptomen und Symptombeschreibungen ist heute selten, war aber im 18. und 19. Jahrhundert eher die Regel.

Methoden In diesem medizinhistorischen Projekt wurden die Todesursachen von 25 Vor- und Nachfahren des Berliner Arztes und Wissenschaftlers Dr. Carl Lüderitz (1854–1930) aus historischen Quellen zusammengetragen und mit Daten zur Todesursachenstatistik des 18. und 19. Jahrhunderts verglichen. Zehn aktiven Gastroenterologen/-innen wurde ein Tagebuchausschnitt des laienhaft beschriebenen Todes eines Berliner Kaufmanns (des Großvaters von Carl Lüderitz) im Jahr 1846 durch seinen Sohn vorgelegt mit der Bitte um eine Verdachtsdiagnose.

Ergebnisse Vier bzw. 5 Fälle von vermutlicher Leberzirrhose unter den 26 Angehörigen der Familie Lüderitz sind überproportional im Vergleich zu Sterbestatistiken in Berlin und auf dem Lande, während die Schwindsucht (Tuberkulose) mit nur einem Fall unterrepräsentiert ist. Durchschnittlich wurden Frauen in dieser Familie 10 Jahre älter, unabhängig vom Jahr des Todes (1787 bis 2006). Acht der befragten Gastroenterologen/-innen waren der Meinung, dass der Tod aufgrund einer dekompensierten Leberzirrhose mit Blutungen aus Ösophagusvarizen eintrat, mit Ödemen auf der Basis einer daraus folgenden Herzinsuffizienz.

Schlussfolgerung Auch historische Dokumente können zur Aus- und Fortbildung oder zur Qualitätskontrolle in der Gastroenterologie beitragen.
Morphological Analysis of Bone Deformities of the Distal Femur in Toy Poodles with Medial Patellar Luxation
Authors: Yasukawa Shinji , Edamura Kazuya , Tanegashima Koji , Seki Mamiko , Asano Kazushi , Nakayama Tomohiro , Hayashi Kei
Published: May 2021

Objective The aim of this study was to evaluate the bone deformities of the distal femur of Toy Poodles with medial patellar luxation (MPL) using computed tomography.

Methods Computed tomography data from 37 stifles of Toy Poodles (16 normal, 10 grade 2 MPL and 11 grade 4 MPL) were analysed. For trochlear morphology, sulcus angle, medial or lateral trochlear inclination and trochlear angle were compared. For condylar morphology, distance between the apex of the medial or lateral trochlear ridge and the most caudal point of the medial or lateral femoral condyle (MC or LC), the length of the cranial/middle (anterior) part (MC(a) or LC(a')) and caudal (posterior) part (MC(p) or LC(p')) of distal femur and medial or lateral condyle width (MCW or LCW) were measured, and the ratios of medial-to-lateral condyles and anterior–posterior parts were compared.

Results Sulcus angle was significantly higher, and medial trochlear inclination was significantly lower in grade 4 MPL group than other groups. Lateral trochlear inclination was not significantly different among 3 groups. Trochlear angles at proximal trochlear groove were significantly lower in grade 4 MPL group than other groups. MC/LC, MC(a)/LC(a'), MC(a)/MC(p), and LC(a')/LC(p') were significantly lower in grade 4 MPL group than other groups; however, there were no significant differences in MC(p)/LC(p') and MCW/LCW among three groups.

Conclusion Hypoplasia of the cranial and middle rather than caudal compartment of the distal femur was the primary morphological abnormality in Toy Poodles with grade 4 MPL.
Catalytic conversion of ethene to butadiene or hydrogenation to ethane on HY zeolite-supported rhodium complexes: Cooperative support/Rh-center route
Authors: Khivantsev Konstantin , Vityuk Artem , Aleksandrov Hristiyan A. , Vayssilov Georgi N. , Alexeev Oleg S. , Amiridis Michael D.
Published: May 2021

Rh(C2H4)2 species grafted on the HY zeolite framework significantly enhance the activation of H2 that reacts with C2H4 ligands to form C2H6. While in this case, the simultaneous activation of C2H4 and H2 and the reaction between these species on zeolite-loaded Rh cations is a legitimate hydrogenation pathway yielding C2H6, the results obtained for Rh(CO)(C2H4)/HY materials exposed to H2 convincingly show that the support-assisted C2H4 hydrogenation pathway also exists. This additional and previously unrecognized hydrogenation pathway couples with the conversion of C2H4 ligands on Rh sites and contributes significantly to the overall hydrogenation activity. This pathway does not require simultaneous activation of reactants on the same metal center and, therefore, is mechanistically different from hydrogenation chemistry exhibited by molecular organometallic complexes. We also demonstrate that the conversion of zeolite-supported Rh(CO)2 complexes into Rh(CO)(C2H4) species under ambient conditions is not a simple CO/C2H4 ligand exchange reaction on Rh sites, as this process also involves the conversion of C2H4 into C4 hydrocarbons, among which 1,3-butadiene is the main product formed with the initial selectivity exceeding 98% and the turnover frequency of 8.9 × 10−3 s−1. Thus, the primary role of zeolite-supported Rh species is not limited to the activation of H2, as these species significantly accelerate the formation of the C4 hydrocarbons from C2H4 even without the presence of H2 in the feed. Using periodic density functional theory calculations, we examined several catalytic pathways that can lead to the conversion of C2H4 into 1,3-butadiene over these materials and identified the reaction route via intermediate formation of rhodacyclopentane.
Petrov–Galerkin methods for the construction of non-Markovian dynamics preserving nonlocal statistics
Authors: Lei Huan , Li Xiantao
Published: May 2021

A common observation in coarse-graining a molecular system is the non-Markovian behavior, primarily due to the lack of scale separations. This is reflected in the strong memory effect and the non-white noise spectrum, which must be incorporated into a coarse-grained description to correctly predict dynamic properties. To construct a stochastic model that gives rise to the correct non-Markovian dynamics, we propose a Galerkin projection approach, which transforms the exhausting effort of finding an appropriate model to choosing appropriate subspaces in terms of the derivatives of the coarse-grained variables and, at the same time, provides an accurate approximation to the generalized Langevin equation. We introduce the notion of fractional statistics that embodies nonlocal properties. More importantly, we show how to pick subspaces in the Galerkin projection so that those statistics are automatically matched.
Hysteresis effect in organic thin film transistors based on naphthalene tetracarboxylic diimide derivatives
Authors: Zhao Changbin , Li Aiyuan , Chen Xiaolong , Ali Muhammad Umair , Meng Hong
Published: May 2021

Controlling the hysteresis effect in organic field-effect transistors (OFETs) is imperative to attain reliable devices that can be applied to complicated circuits for practical applications. In this Letter, we compare two naphthalene tetracarboxylic diimide (NDI) derivatives, namely, N,N′-bis(4-trifluoromethoxybenzyl) naphthalene-1,4,5,8-tetracarboxylic acid diimide (NDI-BOCF3) and N,N′-bis(hexyl) naphthalene-1,4,5,8-tetracarboxylic acid diimide (NDI-C6), which are comprised of different side chains and exhibit significant variations in the hysteresis of electronic transfer potential caused by the electronic traps. Among them, NDI-BOCF3 manifests negligible hysteresis in OFETs, while the counterparts based on NDI-C6 show notable hysteresis. This work presents insight into the hysteresis phenomenon of NDIs in OFETs, which depends on various critical factors, including interfacial trap density, molecular structure, thin film growth mode, and surface energy. Particularly, NDI-C6 demonstrates two orders of magnitude higher interfacial trap density than that of NDI-BOCF3. Moreover, NDI-BOCF3 thin film displays small surface energy and higher surface coverage on the substrate, but the results are diametrically opposite in the case of NDI-C6. Considering these observations, we propose that the introduction of OCF3 group in NDI not only endues a well-matched surface energy that promotes uniform distribution of the thin film on n-Octyltrichlorosilane-modified SiO2 substrate but also provides a water-spelling feature which leads to fewer H2O/O2 absorption in the resulting thin films. Our findings offer a fundamental guideline to rationally design n-type organic semiconductors for the development of efficient OFETs with negligible hysteresis.
Threshold behavior and isotope effect in low-energy electronic stopping of light ions
Authors: Schinner Andreas , Shulga Vladimir I. , Sigmund Peter
Published: May 2021

Electronic excitation of an atom by an ion in the energy regime below ∼20 keV/u can be strongly coupled with elastic scattering. This feature may cause noticeable deviations in the energy loss of light ions such as protons and deuterons from velocity-proportionality and is found to be an essential ingredient in the understanding of the stopping behavior near the threshold. We have incorporated this effect into the PASS stopping code and, in this way, expanded the range of validity of the code down to around 1 keV/u. Comparison of calculated with measured stopping cross sections for protons in Ag, Au, Cu, and Ni shows good agreement with recent data that deviate dramatically from the commonly assumed velocity proportionality. Most of these data were determined by the analysis of reflected-ion spectra. Computation of reflected-ion spectra with energy-loss functions from PASS leads to good agreement with measured spectra. A direct consequence of the coupling with elastic collisions is isotope dependence of the electronic-stopping cross section. Conventional stopping theory denies the existence of a significant isotope effect. Present calculations suggest an effect in the 1–10% range for hydrogen in Si at energies around and below 10 keV/u. This is found to be compatible with experimental data.
Multiphoton induced photoluminescence during time-resolved laser-induced incandescence experiments on silver and gold nanoparticles
Authors: Talebi-Moghaddam S. , Robinson-Enebeli S. , Musikhin S. , Clavel D. J. , Corbin J. C. , Klinkova A. , Smallwood G. J. , Daun K. J.
Published: May 2021

In conventional time-resolved laser-induced incandescence (TiRe-LII) measurements, a laser pulse heats the nanoparticles within a probe volume of aerosol, and the particle size distribution and other characteristics are inferred from the observed incandescence decay rate, which is connected to the change in sensible energy through a spectroscopic model. There is strong evidence, however, that for some aerosol systems, the incandescence signal is contaminated with other non-incandescent emission sources. Recent TiRe-LII measurements on polydisperse aerosolized silver and gold nanoparticles energized with a 1064 nm laser pulse exhibit broadband emission that is temporally aligned with the temporal profile of the laser pulse, suggesting that the signal is due to non-thermal emission. One candidate for this emission phenomenon is multiphoton-induced upconversion luminescence, in which the conduction-band electron gas is heated up to an effective lattice temperature, resulting in luminescence due to high-energy intraband transitions.
Understanding of supramolecular emulsion interfacial polymerization in silico
Authors: Xing Ji-Yuan , Li Sheng , Ma Li-Jun , Gao Hui-Min , Liu Hong , Lu Zhong-Yuan
Published: May 2021

The composition and structure of a membrane determine its functionality and practical application. We study the supramolecular polymeric membrane prepared by supramolecular emulsion interfacial polymerization (SEIP) on the oil-in-water droplet via the computer simulation method. The factors that may influence its structure and properties are investigated, such as the degree of polymerization and molecular weight distribution (MWD) of products in the polymeric membranes. We find that the SEIP can lead to a higher total degree of polymerization as compared to the supramolecular interfacial polymerization (SIP). However, the average chain length of products in the SEIP is lower than that of the SIP due to its obvious interface curvature. The stoichiometric ratio of reactants in two phases will affect the MWD of the products, which further affects the performance of the membranes in practical applications, such as drug release rate and permeability. Besides, the MWD of the product by SEIP obviously deviates from the Flory distribution as a consequence of the curvature of reaction interface. In addition, we obtain the MWD for the emulsions whose size distribution conforms to the Gaussian distribution so that the MWD may be predicted according to the corresponding emulsion size distribution. This study helps us to better understand the controlling factors that may affect the structure and properties of supramolecular polymeric membranes by SEIP.
Two step micro-rheological behavior in a viscoelastic fluid
Authors: Jain Rohit , Ginot Félix , Berner Johannes , Bechinger Clemens , Krüger Matthias
Published: May 2021

We perform micro-rheological experiments with a colloidal bead driven through a viscoelastic worm-like micellar fluid and observe two distinctive shear thinning regimes, each of them displaying a Newtonian-like plateau. The shear thinning behavior at larger velocities is in qualitative agreement with macroscopic rheological experiments. The second process, observed at Weissenberg numbers as small as a few percent, appears to have no analog in macro-rheological findings. A simple model introduced earlier captured the observed behavior and implied that the two shear thinning processes correspond to two different length scales in the fluid. This model also reproduces oscillations, which have been observed in this system previously. While the system under macro-shear seems to be near equilibrium for shear rates in the regime of the intermediate Newtonian-like plateau, the one under micro-shear is thus still far from it. The analysis suggests the existence of a length scale of a few micrometres, the nature of which remains elusive.
Phase behavior of colloid-polymer mixtures in planar, spherical, and cylindrical confinement: A density functional theory study
Authors: Egorov Sergei A.
Published: May 2021

The Asakura–Oosawa (AO) model of colloid–polymer mixtures has been extensively studied over the past several decades both via computer simulations and Density Functional Theory (DFT). At this point, its structural and thermodynamic properties both in the bulk and in contact with flat structureless walls are well understood. At the same time, the phase behavior of AO mixtures in spherical cavities and cylindrical pores, while thoroughly investigated by simulations, has not received a comparably detailed DFT treatment. In this paper, we use the DFT results for the AO model in the bulk and under planar confinement as a point of reference for studying its thermodynamic and structural properties in cavities and pores. The accuracy of the DFT approach is assessed by comparing its predictions with the available extensive simulation data; good overall agreement is generally found with some notable exceptions in the vicinity of wetting and drying transitions. The deviations of the phase behavior in confinement from the bulk phase diagram are analyzed using the Kelvin equation, which is seen to work reasonably well under moderate confinement, i.e., for sufficiently large radii of confining cavities and pores.
Two-dimensional electron systems and interfacial coupling in LaCrO3/KTaO3 heterostructures
Authors: Al-Tawhid Athby H. , Kumah Divine P. , Ahadi Kaveh
Published: May 2021

The strong interfacial coupling at the 3d-5d transition metal-oxide interfaces has generated excitement due to the possibility of engineering a wide range of quantum phenomena and functionalities. Here, we investigate the electronic interfacial coupling and structural properties of LaCrO3/KTaO3 heterostructures. High-quality LaCrO3 films were grown on KTaO3 substrates using molecular beam epitaxy. These heterostructures show a robust two-dimensional electron gas and a metallic behavior down to liquid helium temperature. Using magnetoresistance measurements, we analyze the coupling of electronic orders between Cr 3d and Ta 5d states and observe signatures of weak anti-localization and Kondo scattering at low-temperature transport. The results provide direct evidence that a crossover (weak anti-localization to Kondo) occurs with increasing temperature as the dephasing scattering events reduce the coherence length. Our observations allow for a clear and detailed picture of two distinct quantum corrections to conductivity at low temperature.
Numerical study on rheology of two-dimensional dry foam
Authors: Kim Dokyum , Seol Yunchang , Kim Yongsam
Published: May 2021

We study the mechanical response of two-dimensional aqueous foams subjected to an oscillating shear strain using numerical simulations based on the immersed boundary method. Foams have unique rheological properties ranging from solid-like to fluid-like. They have an elastic property under a small strain with a linear stress-strain relationship. As the strain increases, the foams undergo topological rearrangements with a sudden release of energy and stress. Then the energy-strain and stress-strain curves exhibit hysteresis behaviors under the oscillating shear strain, and the macroscopic response of foams changes from a viscoelastic solid to a viscoelastic fluid. These wide-ranging dynamical responses of foams result from avalanches of topological rearrangements which are concentrated in a single localized region. This is called a shear localization, and we investigate the effect of the topological rearrangements and the shear localization on the rheology of foams.
Interaction of ocean wave with a harbor covered by an ice sheet
Authors: Li Z. F. , Shi Y. Y. , Wu G. X.
Published: May 2021

A domain decomposition method is developed to solve the problem of wave motion inside a harbor with its surface covered by an ice sheet. The shape of the horizontal plane of the harbor can be arbitrary while the sidewall is vertical. The entrance of the harbor is open to the sea with a free surface. The linearized velocity potential theory is adopted for fluid flow, and the thin elastic plate model is applied for the ice sheet. The domain is divided into two subdomains. Inside the harbor, the velocity potential is expanded into a series of eigenfunctions in the vertical direction. The orthogonal inner product is adopted to impose the impermeable condition on the harbor wall, together with the edge conditions on the intersection of the harbor wall and the ice sheet. In the open sea outside of the harbor, through the modified Green function, the velocity potential is written in terms of an integral equation over the surface of the harbor entrance, or the interface between the two subdomains. On the interface, the orthogonal inner product is also applied to impose the continuity conditions of velocity and pressure as well as the free ice edge conditions. Computations are first carried out for a rectangular harbor without the ice sheet to verify the methodology, and then extensive results and discussions are provided for a harbor of a more general shape covered by an ice sheet with different thicknesses and under different incident wave angles.
Analysis of the relative stability of lithium halide crystal structures: Density functional theory and classical models
Authors: Scheiber H. O. , Patey G. N.
Published: May 2021

All lithium halides exist in the rock salt crystal structure under ambient conditions. In contrast, common lithium halide classical force fields more often predict wurtzite as the stable structure. This failure of classical models severely limits their range of application in molecular simulations of crystal nucleation and growth. Employing high accuracy density functional theory (DFT) together with classical models, we examine the relative stability of seven candidate crystal structures for lithium halides. We give a detailed examination of the influence of DFT inputs, including the exchange–correlation functional, basis set, and dispersion correction. We show that a high-accuracy basis set, along with an accurate description of dispersion, is necessary to ensure prediction of the correct rock salt structure, with lattice energies in good agreement with the experiment. We also find excellent agreement between the DFT-calculated rock salt lattice parameters and experiment when using the TMTPSS-rVV10 exchange–correlation functional and a large basis set. Detailed analysis shows that dispersion interactions play a key role in the stability of rock salt over closely competing structures. Hartree–Fock calculations, where dispersion interactions are absent, predict the rock salt structure only for LiF, while LiCl, LiBr, and LiI are more stable as wurtzite crystals, consistent with radius ratio rules. Anion–anion second shell dispersion interactions overcome the radius ratio rules to tip the structural balance to rock salt. We show that classical models can be made qualitatively correct in their structural predictions by simply scaling up the pairwise additive dispersion terms, indicating a pathway toward better lithium halide force fields.
Intrinsic switching in Si-doped HfO2: A study of Curie–Weiss law and its implications for negative capacitance field-effect transistor
Authors: Gastaldi Carlotta , Cavalieri Matteo , Saeidi Ali , O'Connor Eamon , Kamaei Sadegh , Rosca Teodor , Stolichnov Igor , Ionescu Adrian Mihai
Published: May 2021

HfO2-based ferroelectrics are considered a promising class of materials for logic and memory applications due to their CMOS compatibility and ferroelectric figures of merit. A steep-slope field-effect-transistor (FET) switch is a device for logic applications in which a ferroelectric gate stack exploits a stabilized negative capacitance regime capable to differentially amplify the surface potential in a metal–oxide–semiconductor FET structure, resulting in the improvement of the subthreshold swing and overdrive. In a number of relevant studies of negative capacitance, intrinsic (thermodynamic) switching is assumed, since alternative switching scenarios predict undesirable hysteretic responses in logic devices. However, there is little support from the experimental data showing that the polarization reversal in HfO2-based ferroelectrics is really driven by the intrinsic switching mechanism. In this work, polarization hysteresis loops are measured over wide temperature ranges on polycrystalline Si-doped HfO2 (Si:HfO2) capacitors. The analysis herein, which is based on the classic Landau–Ginzburg–Devonshire theory, yields the temperature-dependent dielectric susceptibility values, which fit the Curie–Weiss law. The extrapolated Curie temperature value is in line with the data obtained for other HfO2-based ferroelectrics using different techniques. The work also illustrates a method to evaluate the ferroelectric equivalent negative capacitance value and range of voltages, aiming at study and optimization of a stabilized negative capacitance FET. This study indicates that the intrinsic switching provides an adequate description of the polarization hysteresis in Si:HfO2 films. This confirms the usability of hafnia-based ferroelectrics for negative capacitance logic devices, and the important role that the intrinsic mechanism plays in the dielectric response of these materials.
On irregular Sasaki-Einstein metrics in dimension
Authors: Süß H.
Published: May 2021

We show that there are no irregular Sasaki-Einstein structures on rational homology 5-spheres. On the other hand, using-stability we prove the existence of continuous families of nontoric irregular Sasaki- Einstein structures on odd connected sums of.

Bibliography: 30 titles.
Leep1 interacts with PIP3 and the Scar/WAVE complex to regulate cell migration and macropinocytosis
Authors: Yang Yihong , Li Dong , Chao Xiaoting , Singh Shashi P. , Thomason Peter , Yan Yonghong , Dong Mengqiu , Li Lei , Insall Robert H. , Cai Huaqing
Published: May 2021

Polarity is essential for diverse functions in many cell types. Establishing polarity requires targeting a network of specific signaling and cytoskeleton molecules to different subregions of the cell, yet the full complement of polarity regulators and how their activities are integrated over space and time to form morphologically and functionally distinct domains remain to be uncovered. Here, by using the model system Dictyostelium and exploiting the characteristic chemoattractant-stimulated translocation of polarly distributed molecules, we developed a proteomic screening approach, through which we identified a leucine-rich repeat domain–containing protein we named Leep1 as a novel polarity regulator. We combined imaging, biochemical, and phenotypic analyses to demonstrate that Leep1 localizes selectively at the leading edge of cells by binding to PIP3, where it modulates pseudopod and macropinocytic cup dynamics by negatively regulating the Scar/WAVE complex. The spatiotemporal coordination of PIP3 signaling, Leep1, and the Scar/WAVE complex provides a cellular mechanism for organizing protrusive structures at the leading edge.
The multiplicative constant for the Meijer-G kernel determinant
Authors: Charlier Christophe , Lenells Jonatan , Mauersberger Julian
Published: May 2021

We compute the multiplicative constant in the large gap asymptotics of the Meijer-G point process. This point process generalizes the Bessel point process and appears at the hard edge of Cauchy–Laguerre multi-matrix models and of certain product random matrix ensembles.
On the vanishing viscosity limit for 2D incompressible flows with unbounded vorticity
Authors: Nussenzveig Lopes Helena J , Seis Christian , Wiedemann Emil
Published: May 2021

We show strong convergence of the vorticities in the vanishing viscosity limit for the incompressible Navier–Stokes equations on the two-dimensional torus, assuming only that the initial vorticity of the limiting Euler equations is in L

p
for some p > 1. This substantially extends a recent result of Constantin, Drivas and Elgindi, who proved strong convergence in the case p = ∞. Our proof, which relies on the classical renormalisation theory of DiPerna–Lions, is surprisingly simple.
On the dynamics of contact Hamiltonian systems: I. Monotone systems
Authors: Jin Liang , Yan Jun
Published: May 2021

This article is devoted to a description of the dynamics of the phase flow of monotone contact Hamiltonian systems. Particular attention is paid to locating the maximal attractor (or repeller), which could be seen as the union of compact invariant sets, and investigating its dynamical and topological properties. This is based on an analysis from the viewpoint of gradient-like systems.
Theoretical analyses of magnetoelectric effects for magnetostrictive/radial mode piezoelectric transformer composite under dual ac stress and magnetic field modulation
Authors: Xiao Ning , Wang Yao , Chen Lei , Wen Yumei , Wang Guoqiang , Li Ping , Xiao Rui , Ji Xiaojun , Han Tao
Published: May 2021

Magnetoelectric (ME) composite based on the converse magnetoelectric (CME) effect is promising for the high sensitivity dc and low-frequency magnetic field detection application, however, the performance is restricted by the stress modulation ability of piezoelectric phases and the narrow bandwidth. This work presents a nonlinear equivalent circuit model to design a new ME composite consisting of magnetostrictive layers/radial mode piezoelectric transformer/magnetostrictive layers under dual ac magnetic field and stress modulation. The theoretical model is based on the nonlinear constitutive relationships of magnetostrictive material, motion equation with imperfect interface condition, and improved ME equivalent circuit. This model cannot only predict the resonant ME effects of electrically modulated ME composite under the dual ac stress and magnetic field drive, but can also predict the conventional CME and mutual inductance effects separately. Specifically, the theoretical prediction indicates that with negligible extra power consumption, the dual modulated ME composite provides higher dc and low-frequency magnetic field sensitivity with frequency conversion method and significantly wider bandwidth compared to the conventional CME effect. Such theoretical predictions are further verified by the experimental results of Metglas/piezoelectric transformer/Metglas and Terfenol-D/piezoelectric transformer/Terfenol-D laminate. The theoretical study plays a guiding role in designing the new ME magnetometer with low power consumption, high sensitivity, and wide bandwidth.
Manipulation of the asymmetric Einstein–Podolsky–Rosen steering via coherent population transfer
Authors: Li Jingyan , Chen Quan
Published: May 2021

We investigate the Einstein–Podolsky–Rosen (EPR) steering of two cavity modes generated via four-wave mixing processes. For a three-level V-type configuration, a strong coherent field as a dressing field couples the atoms, and a weak coherent field as a control filed resonantly couples one dressed state to the auxiliary state. By using the approach of dressed states and Bogoliubov modes, we find that only one Bogoliubov mode is mediated into the interaction with the dressed atoms, and the other one is decoupled. Due to the presence of the coherent control filed, the channel for dressed state population transfer is established, which plays a key role in the generation of the asymmetric EPR steering of two cavity fields. It is shown that the one-way EPR steering can be manipulated by the Rabi frequencies of the control field and the cooperativity parameters.
HTS generator, cable and rectifier as a system for hybrid propulsion system
Authors: Kovalev K , Ivanov N , Shishov D. , Zanegin S.
Published: May 2021

Designing systems of future aircraft is a very complex task due to demanding requirements. Superconducting electrical machines and cables could be a solution due to their high specific power. Developing a system which includes an HTS generator, a rectifier, and an HTS cable needs application of analytical techniques. Besides, some optimization techniques should be used to choose proper device parameters in order to provide maximum specific power of the entire system. This paper describes the main principals of developing such a system and provides the results of preliminary calculation of the specification of the system with a 500kW output power.
Simulation of flow over high-lifted turbine cascade at low Reynolds numbers
Authors: Duben A P , Kozubskaya T K , Marakueva O V , Voroshnin D V
Published: May 2021

This paper is dedicated to the simulation of flow in the T106C high loaded turbine cascade. A presence of a laminar-turbulent transition at the suction side of the blade caused by the separation of the boundary layer leads to a significant increase in kinetic energy losses. Predictions using both RANS and scale-resolving methods are carried out. The RANS computations are performed by the SST and BSL-EARSM models with Abu-Ghannam and Shaw criterion of laminar-turbulent transition or the

γ
−

Re

θ
t

˜

model with different closing correlation dependencies. The hybrid RANS-LES IDDES method is used for scale-resolving simulations. The validation is done by comparing the numerical results with the experimental data on the isentropic Mach number along the blade surface and the relative total pressure losses at different Reynolds numbers. The RANS and IDDES results are comparatively analyzed. A strong dependence of all the numerical results on the incoming turbulent flow conditions is observed.
Developing a mathematical model and a computer program for a preliminary design of a transonic axial compressor
Authors: Borovkov A.I. , Galerkin Yu. B. , Solovieva O.A. , Drozdov A.A. , Rekstin A.F. , Semenovsky V.B. , Brodnev P.N.
Published: May 2021

This paper presents a mathematical model underlying the program for calculating and designing axial compressors. The process of calculating pressure loss in the elements of the axial compressor’s stage flow path is described. The loss coefficient consists of losses on the limiting surfaces, secondary losses and profile losses. The effect of roughness on the pressure loss is taken into account by introducing the corresponding empirical coefficient. An algorithm for calculating the blades’ and vanes’ angles of the impeller and the guide apparatus is presented by calculating the incidence angle and the lag angle of the flow. The flow lag angle is the sum of the lag angle of the flow on the profile and the lag angle due to viscous flow on the limiting surfaces.