bluuebunny/crossref_metadata_2025 huggingface dataset:
Unaligned inductance calculation using flux tube approach for rotor conducting screen‐based SRM
Authors: Abdel‐Aziz Aly A. , Ahmed Khaled H. , Massoud Ahmed M. , Williams Barry W.
Published: April 2021

This article investigates the effect of utilising rotor conducting screens within a switched reluctance machine (SRM). Conducting, non‐magnetic materials such as aluminium or copper are inserted into the interpole regions of the rotor. The effective unaligned inductance decreases, which increases the conversion area allowing the machine to develop more power. Predicting machine performance implies knowing the value of the unaligned inductance. A procedure for calculating the effective unaligned inductance for screened motors using the flux tube method is presented. Finite element analysis results establish the validity of the proposed calculation method. A detailed design procedure for screened SRM is presented.
The EXTraS project: Exploring the X-ray transient and variable sky
Authors: De Luca A. , Salvaterra R. , Belfiore A. , Carpano S. , D’Agostino D. , Haberl F. , Israel G. L. , Law-Green D. , Lisini G. , Marelli M. , Novara G. , Read A. M. , Rodriguez-Castillo G. , Rosen S. R. , Salvetti D. , Tiengo A. , Vianello G. , Watson M. G. , Delvaux C. , Dickens T. , Esposito P. , Greiner J. , Hämmerle H. , Kreikenbohm A. , Kreykenbohm S. , Oertel M. , Pizzocaro D. , Pye J. P. , Sandrelli S. , Stelzer B. , Wilms J. , Zagaria F.
Published: April 2021

Temporal variability in flux and spectral shape is ubiquitous in the X-ray sky and carries crucial information about the nature and emission physics of the sources. The EPIC instrument on board the XMM-Newton observatory is the most powerful tool for studying variability even in faint sources. Each day, it collects a large amount of information about hundreds of new serendipitous sources, but the resulting huge (and growing) dataset is largely unexplored in the time domain. The project called Exploring the X-ray transient and variable sky (EXTraS) systematically extracted all temporal domain information in the XMM-Newton archive. This included a search and characterisation of variability, both periodic and aperiodic, in hundreds of thousands of sources spanning more than eight orders of magnitude in timescale and six orders of magnitude in flux, and a search for fast transients that were missed by standard image analysis. All results, products, and software tools have been released to the community in a public archive. A science gateway has also been implemented to allow users to run the EXTraS analysis remotely on recent XMM datasets. We give details on the new algorithms that were designed and implemented to perform all steps of EPIC data analysis, including data preparation, source and background modelling, generation of time series and power spectra, and search for and characterisation of different types of variabilities. We describe our results and products and give information about their basic statistical properties and advice on their usage. We also describe available online resources. The EXTraS database of results and its ancillary products is a rich resource for any kind of investigation in almost all fields of astrophysics. Algorithms and lessons learnt from our project are also a very useful reference for any current and future experiment in the time domain.
R-process enhancements of Gaia-Enceladus in GALAH DR3
Authors: Matsuno Tadafumi , Hirai Yutaka , Tarumi Yuta , Hotokezaka Kenta , Tanaka Masaomi , Helmi Amina
Published: April 2021

Context. The dominant site of production of r-process elements remains unclear despite recent observations of a neutron star merger. Observational constraints on the properties of the sites can be obtained by comparing r-process abundances in different environments. The recent Gaia data releases and large samples from high-resolution optical spectroscopic surveys are enabling us to compare r-process element abundances between stars formed in an accreted dwarf galaxy, Gaia-Enceladus, and those formed in the Milky Way.

Aims. Our aim is to understand the origin of r-process elements in Gaia-Enceladus.

Methods. We first constructed a sample of stars so that our study on Eu abundance is not affected by the detection limit. We then kinematically selected 76 Gaia-Enceladus stars and 81 in situ stars from the Galactic Archaeology with HERMES (GALAH) DR3, of which 47 and 55 stars, respectively, can be used to study Eu reliably.

Results. Gaia-Enceladus stars clearly show higher ratios of [Eu/Mg] than in situ stars. High [Eu/Mg] along with low [Mg/Fe] are also seen in relatively massive satellite galaxies such as the LMC, Fornax, and Sagittarius dwarfs. On the other hand, unlike these galaxies, Gaia-Enceladus does not show enhanced [Ba/Eu] or [La/Eu] ratios suggesting a lack of significant s-process contribution. From comparisons with simple chemical evolution models, we show that the high [Eu/Mg] of Gaia-Enceladus can naturally be explained by considering r-process enrichment by neutron-star mergers with delay time distribution that follows a power-law similar to type Ia supernovae but with a shorter minimum delay time.
Cosmological implications of the anisotropy of ten galaxy cluster scaling relations
Authors: Migkas K. , Pacaud F. , Schellenberger G. , Erler J. , Nguyen-Dang N. T. , Reiprich T. H. , Ramos-Ceja M. E. , Lovisari L.
Published: April 2021

The hypothesis that the late Universe is isotropic and homogeneous is adopted by most cosmological studies, including studies of galaxy clusters. The cosmic expansion rateH0is thought to be spatially constant, while bulk flows are often presumed to be negligible compared to the Hubble expansion, even at local scales. The effects of bulk flows on the redshift–distance conversion are hence usually ignored. Any deviation from this consensus can strongly bias the results of such studies, and thus the importance of testing these assumptions cannot be understated. Scaling relations of galaxy clusters can be effectively used for this testing. In previous works, we observed strong anisotropies in cluster scaling relations, whose origins remain ambiguous. By measuring many different cluster properties, several scaling relations with different sensitivities can be built. Nearly independent tests of cosmic isotropy and large bulk flows are then feasible. In this work, we make use of up to 570 clusters with measured properties at X-ray, microwave, and infrared wavelengths to construct ten different cluster scaling relations and test the isotropy of the local Universe; to our knowedge, we present five of these scaling relations for the first time. Through rigorous and robust tests, we ensure that our analysis is not prone to generally known systematic biases and X-ray absorption issues. By combining all available information, we detect an apparent 9% spatial variation in the localH0between (l, b)∼(280°−35°+35°, −15°−20°+20°) and the rest of the sky. The observed anisotropy has a nearly dipole form. Using isotropic Monte Carlo simulations, we assess the statistical significance of the anisotropy to be > 5σ. This result could also be attributed to a ∼900 km s−1bulk flow, which seems to extend out to at least ∼500 Mpc. These two effects will be indistinguishable until more high-zclusters are observed by future all-sky surveys such as eROSITA.
New E-Commerce Model and Development Strategy of Fresh Food E-Commerce Platform Based on ReTech
Authors: Sun Xi
Published: April 2021

With the arrival of the new retail format, almost every e-commerce platform has arranged fresh food retail one after another. Retech integrates retail and technology organically to enhance the core competitiveness of retail industry in the aspects of automation and intelligence. This paper introduces the four business models of fresh e-commerce and the transformation of circulation model of agricultural products, compares the circulation model of traditional retail and fresh e-commerce, analyses the characteristics of consumption demand of fresh e-commerce, and gives the development strategy of fresh e-commerce platform based on Retech.
Research on the Cultivation Model of Diversified Application Talents for Broadcasting and Television Directors Based on Cloud Network Platform
Authors: Li Nan , Chen Xiaoxu
Published: April 2021

In recent years, Internet has developed rapidly. The original mode of cultivating talents for radio and television directors in our undergraduate colleges no longer satisfy the needs of the current society. The talents cultivated in colleges and universities cannot match the talents needed by society. Many college students are facing graduation and unemployed, and employers are also worried about that they cannot find suitable talents. In order to adapt to the development of the society, the teaching method of the radio and television director major must be reformed. Based on the original theoretical basic knowledge, it is necessary to strengthen the students’ data analysis and practical skills, they should assess the current situation and absorb excellent domestic and foreign students in the curriculum configuration. Cultivate experience, but it must conform to the current situation in our country.
Measurement Analysis of Trade Facilitation in China-asean Free Trade Area
Authors: Sun Lili
Published: April 2021

Economic and trade cooperation between China and ASEAN countries has made new progress with the introduction of the concept of Belt and Road. In 2015, China and ASEAN formally signed the outcome document of negotiations on an upgraded free trade area, which shows that China-asean relations have became better. Enhancing the trade facilitation level of the Free Trade Area can improve the economic and trade exchanges between China and ASEAN. The premise of studying how to improve the trade facilitation level of Free Trade Area is to measure the trade facilitation level of free trade area. In this paper, trade facilitation is divided into four categories and 19 sub-indexes, and the measurement model of trade facilitation in free trade area is established to measure the trade facilitation level between China and ASEAN countries.
Comparative Study on Categories and Services of Fresh E-Commerce Platforms
Authors: Sun Xi
Published: April 2021

Fresh e-commerce has attracted the attention of the capital market for its hundreds billion market scale, high repurchase rate, big market demand and large profits. More and more young and middle-aged people choose fresh e-commerce as the channel of fresh purchase to achieve faster speed, higher quality and more commodity categories. The price is no longer the only factor for consumers, especially for young and middle-aged consumers. This paper makes a comparative analysis of five fresh e-commerce platforms in terms of delivery time, third-party occupancy, and minimum consumption of “free distribution fee”, members, communities, payment preferences, and e-commerce platform interface. In this paper, one hundred consumers are selected to evaluate the scores in respective modules, and the operation models of fresh e-commerce platform with different characteristics are comprehensively displayed. The paper points out that providing more quality and differentiated services has become an important competitive key point in the market.
Study on the Impact of Production Agglomeration of China’s Aquatic Products on Export Competitiveness
Authors: Fu Weiwei , Zhuang Peifen
Published: April 2021

This paper collects the data of China’s aquatic products from 2002 to 2018 and studies the relationship between the production agglomeration and export competitiveness of aquatic products. This paper calculates the production Concentration Rate (CR) which reflects the degree of agglomeration of aquatic products and the Revealed Comparative Advantage (RCA) index which reflects the export competitiveness of aquatic products, and then uses variable intercept model with fixed effects to empirically analyze the impact of production agglomeration of three main aquatic products (fish, crustacean and shellfish) on the export competitiveness. The results show that there is an obvious phenomenon of production agglomeration of aquatic products in China. Overall, the improvement of production agglomeration of aquatic products is conducive to the promotion of export competitiveness.
Coordinated development of agricultural economy and rural tourism based on big data
Authors: Tang Qinya , Lou Yuqing , Chen Kelin
Published: April 2021

In China’s national economic system, the agricultural economy is an important component. Regardless of the development model, development direction and scale of the agricultural economy, it will have an important impact on the development and progress of the national economy. As the country attaches great importance to agricultural development, the reform of agricultural development is gradually being deepened. The application of big data can effectively analyze the agricultural economy and rural tourism market information, which is conducive to promoting the coordinated development of the two. At the same time, China has put forward a strategy of “village revitalization”, which brings new development opportunities for agricultural economy and rural tourism. Based on this, this article first analyzes the connotation and characteristics of big data, then introduces the development of agricultural economy and rural tourism under big data, and finally discusses the strategy of combining the two to improve the overall quality of rural economic development.
Research on Collaborative Development Strategies of the Tourism Logistics Industry in Wuhan
Authors: T Liu , Y H Ning
Published: April 2021

The new growth points of two major industries—tourism industry and logistics industry—can be fully utilized to reach the effect of 1+1>2 by promoting their collaborative development. It is suitable to boost the tourism logistics collaborative development in Wuhan, which integrates various advantages in traffic location and resources, tourist market and industrial development, policy opportunity, etc. In this research, the tourism logistics collaborative development model in Wuhan was expounded from three aspects: planning and design of tourism logistics route, integrated design of tourist commodity logistics, and tourism waste logistics collaborative treatment system, expecting that Wuhan can grasp the opportunity and provide policy support, technical support and financial support to promote the collaborative development of the tourism logistics industry and accelerate the healthy development of Wuhan.
Research on the Coordinated Development Mechanism of supply chain finance among countries under the development of Internet Era
Authors: Lan Yong , Miao Ning , Wang Yan Ya , Feng Ming Yong , Liu Dong Xia
Published: April 2021

This paper studies the international supply chain finance among trading countries under the Internet financial environment. By introducing “One Belt And One Road” and “supply chain finance”, this paper analyzes the main supply chain finance models involved in the “One Belt And One Road” strategy, and uses clustering method to analyze and summarize the financial risks of supply chain. The analysis results are obtained through data mining reasoning. On this basis, it mainly uses Internet information technology, big data analysis and other technologies to deal with the risks in the international supply chain, and puts forward constructive suggestions to promote the coordinated development of supply chain finance among countries.
Effects of biochar on nitrogen and phosphorus retention in the coastal wetland soil of the Yellow River Delta, China
Authors: Miao Jing , Li Xiaotong , Wang Xiao
Published: April 2021

Nutrient deficiency (nitrogen, phosphorus) strongly limited the productivity of the degraded coastal soils in the Yellow River Delta. Biochar (BC) is a kind of porous carbonaceous material. It has raised wide interests because of their multiple benefits in soil improvement. The effects of biochar on the retention of nitrogen and phosphorus varied with the types of biochar and soil properties. In this study, a maize straw derived BC was applied into a coastal salt-affected soil collected from the Yellow River Delta to investigate the response of soil nutrient using a three-month cultivating experiment with the simulated rainfall. The results showed that the addition of biochar reduced the content of NH4+-N and NO3--N in all-depth soil by 8.1–27.0% and 25.3–51.9%, respectively. The content of TP in 0-30 cm soil was significantly increased, while it had no significant effect on the content of TP in 30-60 cm soil. These findings would provide theoretical basis and technical support for developing feasible technologies for remediating degraded coastal wetland soil.
Research development in tumor therapy: role of iron-related nanoparticles
Authors: Peipei Dai
Published: April 2021

As an essential nutrient element for life, iron’s metabolic balance in body tissues is crucial to sustaining normal physiological functions, and it is inextricably related to tumors. Nanotechnology is gaining much attention around the world for cancer treatment. Considering the critical role of iron metabolism, nanocarriers’ toxicity and biocompatibility, novel nanomaterials based on the biochemical activity of iron and the regulatory proteins of iron homeostasis-metabolism show broad application prospects in the field of tumor diagnosis and treatment. In this review, the role of iron-related nanocarriers for tumor therapy, such as iron oxide nanoparticles, Fe-based metal-organic frameworks, ferritin, and transferrin, was reviewed, aiming to help people better understand their tremendous potential in tumor therapy.
Characteristics and upregulation of antioxidant capacity of fermented pueraria starch production wastewater with kombucha consortium
Authors: Lu Zhixin , Jiang Hongting , Chen Zhongqiang , Zhai Yin , Yuan Fahu
Published: April 2021

Pueraria lobata is a traditional plant used for both medicine and food. Pueraria starch has a long history of folk consumption in China. The processing of pueraria starch produces a lot of waste water and is often discarded, but it contains rich nutrients and is suitable for the growth of microorganisms. In this study, pueraria starch processing wastewater was used as a new fermentation substrate for kombucha fungus to develop a new functional beverage. After 8 days of static fermentation in 28 °C, the pH of kombucha fermented with pueraria starch processing wastewater as substrate decreased to 2.78, the total acid concentration was 0.158 mol/L, and the mass concentration of reducing sugar decreased to 2.05 mg/mL. The pueraria starch production wastewater before and after fermentation was extracted with 80% methanol and the mass concentration of total flavonoids was determined. The antioxidant activity of pueraria starch processing wastewater before and after fermentation was analyzed by using three antioxidant models: DPPH free radical scavenging ability, ABTS cationic free radical scavenging ability and ferrous ion reducing power. The results showed that after 7 days of fermentation, the mass concentration of total flavonoids in kombucha produced by the pueraria starch processing wastewater was 268.45 mg/L. The antioxidant activity of fermented kombucha beverage was significantly higher than that of unfermented pueraria starch processing wastewater. This study provides a new way for the resource utilization of Pueraria starch processing wastewater.
Research Progress on Nutrient Composition of Green Pepper
Authors: Xie Zhengwei , Peng Wanyun , Ma Qianqian , Wang Zhide , Wu Peng
Published: April 2021

Green pepper is an important traditional spices in China, with food flavor and various pharmacological functions. Based on the literature at home and abroad, the nutritional components of green pepper are systematically reviewed to provide a theoretical basis for the comprehensive utilization of green pepper.
Research on the Forecast of Urban Underground Space Demand
Authors: Xin Lin , Zhehua Du
Published: April 2021

Forecasting the capacity demand of underground space is the difficulty and a heat point in urban planning and urban underground space development. Through the survey data of Shanghai underground space capacity in 2006 and 2008, this paper conducts an empirical study on forecasting the capacity demand of underground space using thespatial regression model as the classical model by applying tools of STATA, SPSS and ArcGIS. The study indicates that the scale of underground space development and use is in a significant positive relationship with the population density and GDP per capita, but is not relevant with the price of real estate. The characteristics are apparently different in the underground space development and use in Shanghai between the central and the rural area. The underground space development in Shanghai is at the stage of rapid promotion, and will keep increasing at a high speed. The paper reveals the development law of Shanghai underground space development and the method of forecasting the capacity of underground space so as to provide theoretical analysis tool for development of underground space in Shanghai and other cities.
The role and path of digital marketing in tourist souvenir brands
Authors: Shiqun Yuan , Chengjun Zhou , Yu Zhang
Published: April 2021

The extensive and in-depth application of digital technology has led to the transformation of marketing methods. This article analyzes the role and path of digital marketing in tourist souvenir brands through case studies, expert interviews and literature studies. The findings suggest that the rational use of digital technology can not only reshape brand competitiveness, but also play a role in deepening product integration and enhancing brand communication. To realize digital marketing of tourist souvenir brands, it is necessary to formulate effective brand marketing strategies and create a personalized brand image in order to realize the conversion of cultural and creative product sales.
Study on the Influence of Health and Wellness Tourists’ Pull Motivation on Revisit Intention-- the Moderating Role of the Push Motivation
Authors: Ting Tao , Changtai Lu , Linjun He , Zhiping Zheng
Published: April 2021

Health and wellness tourism is a new form of tourism in which people seek to experience a healthy lifestyle through tourism. From the perspective of demand side, this paper discusses the tourism motivation of health and wellness tourists, and based on a new tourism motivation model, studies the influence mechanism of pull motivation on revisit intention. The results showed that:(1) Pull motivation had a significant positive effect on revisit intention; (2) pushing motivation negatively moderates the relationship between pull motivation and revisit intention.
Employee quality, internal control and corporate social responsibility: An empirical study from a perspective of informatization management
Authors: Wang Liangcheng , Liao Yifan
Published: April 2021

Recently, the COVID-19 has swept the whole world. Under this situation, the firm, as a member of the society, should also undertake social responsibilities to jointly respond to the COVID-19. The employee, as a principal part of firm, plays an important role in informatization management which may affects the level of corporate social responsibility. Their ability of informatization management will inevitably affect their access to the information of corporate social responsibility, thus affecting the level of corporate social responsibility. This paper takes A-share listed companies from 2011 to 2018 collected in CSMAR as samples to explore the relations between employees’ ability of informatization and corporate social responsibility. This study, as an interdisciplinary research related to computer and management, adopts OLS, IV method and other mathematics methods to build models. Using the employee education level as a proxy for employees’ ability of informatization management, this paper finds that firms with a high-quality workforce exhibit higher level of corporate social responsibility, especially in the areas with lower degree of marketization. According to the further analysis using the model of Sobel test, the internal control plays a mediating role between employees’ ability of informatization management and corporate social responsibility. This study suggests that employee quality plays an important role in performing corporate social responsibility. This study should be of interest to top managers and regulators who wish to use information technology to improve corporate social responsibility.
Application of Internet Technology in Ideological and Political Practice Teaching
Authors: Liu Yuan
Published: April 2021

Practical teaching is an important content of ideological and political teaching. Using the advantages of Internet technology can not only broaden the teaching scope of ideological and political practical teaching, but also improve the efficiency and quality of ideological and political practical teaching. This article combines the current situation of ideological and political teaching, and analyzes the characteristics and advantages of Internet technology, and discusses and analyzes the application of Internet technology in ideological and political practical teaching in terms of practical teaching content, teaching methods, and teaching evaluation. The author further thought about how to better integrate Internet technology with ideological and political practice teaching, and give full play to the role of Internet technology in ideological and political teaching.
The Design on Dance Teaching Mode of Personalized and Diversified in the Context of Internet
Authors: Mao Rong
Published: April 2021

Traditional dance teaching emphasizes the consistency model and lacks the exploration of students’ individual characteristics. However, individualized and diversified dance education is a diversified dance talent cultivation oriented to different objects and objectives according to the differences of students’ natural conditions, educational background and development needs. Due to the single and real-time traditional dance teaching mode, there are limitations in the realization of multi-attribute and multi-objective dance talent training. This paper establishes a dance teaching situation with the function of network interaction, and solves the difficulties in individualized and diversified dance teaching. The research shows that the integration of online and offline education mode not only has certain theoretical value in teaching, but also has great practical significance for the cultivation of personalized and diversified dance talents.
Exploring the Focus of Enterprise Informatization During Digital Transformation
Authors: GuQian Lin-Yu
Published: April 2021

As an irreversible trend in nowadays manufacturing industry, digital transformation has put higher demands on enterprise’s informatization. This paper reviewed how the focus changed for enterprise informatization in the manufacturing industry during each development stage, summarized the development trend for informatization in the industry, and put forward the three focuses of enterprise informatization during digital transformation. In a new historical stage, enterprises should focus their efforts on the following aspects: integrating informatization with lean management to optimize the value system as much as possible; building an integrated management model to achieve overarching control on informatization; realizing in-depth integration of informatization and industrialization to follow a path to new industrialization.
Construction of a low Mach finite volume scheme for the isentropic Euler system with porosity
Authors: Dellacherie Stéphane , Jung Jonathan , Omnes Pascal
Published: April 2021

Classical finite volume schemes for the Euler system are not accurate at low Mach number and some fixes have to be used and were developed in a vast literature over the last two decades. The question we are interested in in this article is: What about if the porosity is no longer uniform? We first show that this problem may be understood on the linear wave equation taking into account porosity. We explain the influence of the cell geometry on the accuracy property at low Mach number. In the triangular case, the stationary space of the Godunov scheme approaches well enough the continuous space of constant pressure and divergence-free velocity, while this is not the case in the Cartesian case. On Cartesian meshes, a fix is proposed and accuracy at low Mach number is proved to be recovered. Based on the linear study, a numerical scheme and a low Mach fix for the non-linear system, with a non-conservative source term due to the porosity variations, is proposed and tested.
Hepatic Trauma Interventions
Authors: Pillai Akshita S. , Kumar Girish , Pillai Anil K.
Published: April 2021

The liver is the second most commonly involved solid organ (after spleen) to be injured in blunt abdominal trauma, but liver injury is the most common cause of death in such trauma. In patients with significant blunt abdominal injury, the liver is involved approximately 35 to 45% of the time. Its large size also makes it a vulnerable organ, commonly injured in penetrating trauma. Other than its position and size, the liver is surrounded by fragile parenchyma and its location under the diaphragm makes it vulnerable to shear forces during deceleration injuries. The liver is also a vascular organ made of large, thin-walled vessels with high blood flow. In severe hepatic trauma, hemorrhage is a common complication and uncontrolled bleeding is usually fatal. In fact, in patients with severe abdominal trauma, liver injury is the primary cause of death. This article reviews the clinical presentation of patients with liver injury, the grading system for such injuries that is most frequently used, and management of the patient with liver trauma.
Representation of Diagnosis and Nursing Interventions in OpenEHR Archetypes
Authors: Gomes Denilsen Carvalho , Abreu Nuno , Sousa Paulino , Moro Claudia , Carvalho Deborah Ribeiro , Cubas Marcia Regina
Published: April 2021

Objective The study aimed to represent the content of nursing diagnosis and interventions in the openEHR standard.

Methods This is a developmental study with the models developed according to ISO 18104: 2014. The Ocean Archetype Editor tool from the openEHR Foundation was used.

Results Two archetypes were created; one to represent the nursing diagnosis concept and the other the nursing intervention concept. Existing archetypes available in the Clinical Knowledge Manager were reused in modeling.

Conclusion The representation of nursing diagnosis and interventions based on the openEHR standard contributes to representing nursing care phenomena and needs in health information systems.
Correction to: Governance of Eswatini Apparel Regional Value Chains and the Implications of Covid-19
Authors: Pasquali Giovanni , Godfrey Shane
Published: April 2021

A correction to this paper has been published: https://doi.org/10.1057/s41287-021-00392-2
Meshing two techniques to reveal mechanisms underlying immunobullous skin diseases
Authors: Patrick Chris
Published: April 2021

Three proof-of-principle experiments demonstrate the potential of a method that pairs magnetic tweezers with traction force microscopy.
Fuel convergence sensitivity in indirect drive implosions
Authors: Landen O. L. , Lindl J. D. , Haan S. W. , Casey D. T. , Celliers P. M. , Fittinghoff D. N. , Gharibyan N. , Goncharov V. N. , Grim G. P. , Hartouni E. P. , Hurricane O. A. , MacGowan B. J. , MacLaren S. A. , Meaney K. D. , Millot M. , Milovich J. L. , Patel P. K. , Robey H. S. , Springer P. T. , Volegov P. L. , Edwards M. J.
Published: April 2021

In inertial confinement fusion experiments at the National Ignition Facility, a spherical shell of deuterium–tritium fuel is imploded in an attempt to reach the conditions needed for fusion, self-heating, and eventual ignition. Since theory and simulations indicate that ignition efficacy in 1D improves with increasing imploded fuel convergence ratio, it is useful to understand the sensitivity of the scale-invariant fuel convergence on all measurable or inferable 1D parameters. In this paper, we develop a simple isobaric and isentropic compression scaling model incorporating sensitivity to the in-flight adiabat inferred from shock strengths, to measured implosion velocity, and to known initial ablator and fuel aspect ratio and mass ratio. The model is first benchmarked to 1D implosion simulations spanning a variety of relevant implosion designs. We then use the model to compare compressibility trends across all existing indirect-drive layered implosion data from the facility spanning three ablators [CH, carbon (C), and Be], for which in-flight fuel adiabats varied from 1.6 to 5 by varying the number of drive shocks from 2 to 4, peak implosion velocities varied by 1.4×, capsule radii by 50%, and initial fuel aspect ratios by 1.4×. We find that the strength of the first shock is the dominant contributor setting the maximum fuel convergence. We also observe additional sensitivities to successive shock strengths and fuel aspect ratios that improve the agreement between the expected and measured compression for carbon and Be designs with adiabats above 3. A principal finding is that the adiabat 2.5 C-shell designs exhibit less convergence than CH-shell designs of similar inferred in-flight adiabat.
Classification of fold/hom and fold/Hopf spike-adding phenomena
Authors: Barrio Roberto , Ibáñez Santiago , Pérez Lucía , Serrano Sergio
Published: April 2021

The Hindmarsh–Rose neural model is widely accepted as an important prototype for fold/hom and fold/Hopf burstings. In this paper, we are interested in the mechanisms for the production of extra spikes in a burst, and we show the whole parametric panorama in an unified way. In the fold/hom case, two types are distinguished: a continuous one, where the bursting periodic orbit goes through bifurcations but persists along the whole process and a discontinuous one, where the transition is abrupt and happens after a sequence of chaotic events. In the former case, we speak about canard-induced spike-adding and in the second one, about chaos-induced spike-adding. For fold/Hopf bursting, a single (and continuous) mechanism is distinguished. Separately, all these mechanisms are presented, to some extent, in the literature. However, our full perspective allows us to construct a spike-adding map and, more significantly, to understand the dynamics exhibited when borders are crossed, that is, transitions between types of processes, a crucial point not previously studied.
On the analytical and numerical solutions of the damped nonplanar Shamel Korteweg–de Vries Burgers equation for modeling nonlinear structures in strongly coupled dusty plasmas: Multistage homotopy perturbation method
Authors: El-Tantawy S. A. , Salas Alvaro H. , Alharthi M. R.
Published: April 2021

The dissipative cylindrical and spherical (nonplanar) electrostatic low-frequency dust-acoustic waves (DAWs) including solitary and shock waves in a collisional and unmagnetized strongly coupled dusty plasma are investigated analytically and numerically. The present plasma model consists of inertialess particles including thermal elections and vortex-like positive ions distribution as well as inertial strongly coupled negatively charged dust grains. In the hydrodynamic regime, the fluid governed equations of the present model are reduced to the damped nonplanar Shamel Korteweg–de Vries Burgers (SKVB) equation using the reductive perturbation technique. In the absence of the dissipative effect, the damped nonplanar Shamel Korteweg–de Vries (SKdV) equation is recovered and solved analytically for the first time using a novel analytical approach in order to describe the dynamical mechanism of the dissipative nonplanar dust-acoustic solitary waves. Also, the damped nonplanar SKdV equation is solved numerically using the homotopy perturbation method (HPM) and the hybrid homotopy perturbation method with the moving boundary method which is called multistage HPM (MsHPM). Furthermore, in the presence of the dissipative effect, the damped nonplanar SKdVB equation is solved numerically via the HPM and MsHPM for studying the characteristics of the dissipative nonplanar dust-acoustic solitary and shock waves. For checking the accuracy of the obtained solutions, the maximum global residual error is estimated. Moreover, a comparison between the approximate analytical and numerical solutions is reported. Furthermore, the dependence of dissipative nonplanar structures (solitons and shocks) characteristics on various plasma parameters is examined.
Phase-transition critical thickness of rocksalt MgxZn1−xO layers
Authors: Dłużewski Paweł , Domagala Jaroslaw Z. , Kret Sławomir , Jarosz Dawid , Kryśko Marcin , Teisseyre Henryk
Published: April 2021

The rocksalt structure of ZnO has a very promising bandgap for optoelectronic applications. Unfortunately, this high-pressure phase is unstable under ambient conditions. This paper presents experimental results for rocksalt-type ZnO/MgO superlattices and theoretical considerations of the critical thickness of MgxZn1−xO layers. The correlations between the layer/spacer thickness ratio, elastic strain, chemical composition, and critical thickness are analyzed. The Matthews and Blakeslee model is revisited to find analytic conditions for the critical layer thickness resulting in phase transition. Our analysis shows that due to the decrease in misfit stresses below some critical limit, the growth of multiple quantum wells composed of rocksalt ZnO layers and MgO spacers is possible only for very large layer/spacer thickness ratios.
Crystal facet engineering for production of TiO2/WO3 photoelectrodes with superior energy storage capacity
Authors: Hirai Makoto , Tsuzuki Keita , Fujita Naoyuki
Published: April 2021

WO3 thin films with (002)-preferred orientation showing superior electron storage capacity were prepared using a vacuum evaporation system. The electron storage capacity of the WO3 photoelectrode can be improved by controlling the crystallographic orientation of the WO3 crystals. In photoelectrochemical water splitting, the TiO2/WO3 photoelectrode exhibited a significantly higher increment in current density than the pristine WO3 photoelectrode. The charging and discharging capacities of the preferentially oriented WO3 layer can be derived in full value to introduce a TiO2 layer with a porous morphology. Moreover, because a difference in the crystal facet results in a slight change in the energy of the valence and conduction bands, it can be speculated that better separation of electron–hole pairs is achieved, leading to exposure of the (002) dominant crystal facet of WO3.
Wave trapping and E × B staircases
Authors: Garbet X. , Panico O. , Varennes R. , Gillot C. , Dif-Pradalier G. , Sarazin Y. , Grandgirard V. , Ghendrih P. , Vermare L.
Published: April 2021

A model of E × B staircases is proposed based on a wave kinetic equation coupled to a poloidal momentum equation. A staircase pattern is idealized as a periodic radial structure of zonal shear layers that bound regions of propagating wave packets, viewed as avalanches. Wave packets are trapped in shear flow layers due to refraction. In this model, an E × B staircase motif emerges due to the interaction between propagating wave packets (avalanches) and trapped waves in the presence of an instability drive. Amplitude, shape, and spatial period of the staircase E × B flow are predicted as functions of the background fluctuation spectrum and the growth rate of drift waves. The zonal flow velocity radial profile is found to peak near its maxima and to flatten near its minima. The optimum configuration for staircase formation is a growth rate, that is, maximum at zero radial wave number. A mean shear flow is responsible for a preferential propagation speed of avalanches. It is not a mandatory condition for the existence of staircase solutions, but has an impact on their spatial period.
W-band millimeter-wave back-scattering system for high wavenumber turbulence measurements in LHD
Authors: Tokuzawa T. , Tanaka K. , Tsujimura T. , Kubo S. , Emoto M. , Inagaki S. , Ida K. , Yoshinuma M. , Watanabe K. Y. , Tsuchiya H. , Ejiri A. , Saito T. , Yamamoto K. ,   LHD Experiment Group
Published: April 2021

A 90 GHz W-band millimeter-wave back-scattering system is designed and installed for measuring electron scale turbulence (k⊥ρs ∼ 40). A metal lens relay antenna is used for in-vessel beam focusing, and a beam diameter of less than 40 mm is achieved in the plasma core region. This antenna can be steered at an angle of 159° ± 6°, which almost covers the plasma radius. The estimated size of the scattering volume is ∼105 mm at the edge and 135 mm at the core, respectively. A 60 m corrugated waveguide is used to achieve a low transmission loss of ∼8 dB. A heterodyne detection system for millimeter-wave circuits with probing power modulation can distinguish the scattered signal from background noise.
A new tangential gamma-ray spectrometer for fast ion measurements in deuterium and deuterium–tritium plasmas of the Joint European Torus
Authors: Nocente M. , Craciunescu T. , Gorini G. , Kiptily V. , Tardocchi M. , Braic V. , Curuia M. , Dal Molin A. , Figueiredo J. , Giacomelli L. , Iliasova M. , Kazakov Y. , Khilkevitch E. , Marcer G. , Panontin E. , Rigamonti D. , Salewski M. , Shevelev A. , Soare S. , Zoita V. , Zychor I. ,   JET Contributors
Published: April 2021

A new tangential gamma-ray spectrometer has been developed for fast ion measurements in deuterium and deuterium–tritium plasmas of the Joint European Torus (JET). The instrument is based on a LaBr3 crystal with a photo-multiplier tube and replaces a pre-existing bismuth germanate detector, providing enhanced energy resolution and a counting rate capability in the MHz range. The line of sight is equipped with a LiH attenuator, which reduces the background due to 14 MeV neutron interactions with the crystal by more than two orders of magnitude and enables the observation of gamma-ray emission from confined α particles in JET deuterium–tritium plasmas. Thanks to its tangential line of sight, the detector can distinguish co- and counter-passing ions. The performance of the instrument is demonstrated through the results of recent JET fast ion experiments in deuterium plasmas.
Radially resolved active charge exchange measurements of the hydrogenic isotope fraction on DIII-D
Authors: Haskey S. R. , Stagner L. , Grierson B. A. , Chrystal C. , DeGrandchamp G. H. , Heidbrink W. W. , Van Zeeland M. A. , Vincena S.
Published: April 2021

Radially resolved hydrogenic isotope fraction measurement capabilities have been developed for DIII-D using the main-ion charge exchange recombination (MICER) spectroscopy system in preparation for mixed hydrogen and deuterium experiments. Constraints on the hydrogenic ion temperatures and velocities based on measurements of the impurity ion properties are required to accurately fit the spectrum. Corrections for cross sectional distortions, spatial smearing due to the halo, and a neoclassical offset between the impurity and hydrogenic toroidal rotation are applied to the constraints prior to fitting the MICER spectrum. Extensive atomic physics calculations have been performed using the FIDASIM code, which has recently been improved to allow simulations using mixtures of hydrogenic species. These results demonstrate that for the same plasma parameters, the Dα emission is 20%–30% brighter than Hα due to differences in rate coefficients associated with the different ion thermal velocities for the same temperature and therefore must be taken into consideration when calculating absolute densities. However, despite these differences, the absolute error when estimating the hydrogen isotope fraction [nH/(nH + nD)] by using the Hα radiance fraction [LHα/(LHα + LDα)] is typically less than 5% due to the way the fraction is formed, making the radiance fraction a reasonably accurate estimate of the isotope fraction for most cases.
A comparative study of force fields for predicting shape memory properties of liquid crystalline elastomers using molecular dynamic simulations
Authors: Prathumrat P. , Sbarski I. , Hajizadeh E. , Nikzad M.
Published: April 2021

Molecular dynamic (MD) simulation techniques are increasingly being adopted as efficient computational tools to design novel and exotic classes of materials for which traditional methods of synthesis and prototyping are either too costly, unsafe, and time-consuming in laboratory settings. Of such class of materials are liquid crystalline elastomers (LCEs) with favorable shape memory characteristics. These materials exhibit some distinct properties, including stimuli responsiveness to heat or UV and appropriate molecular structure for shape memory behaviors. In this work, the MD simulations were employed to compare and assess the leading force fields currently available for modeling the behavior of a typical LCE system. Three force fields, including Dreiding, PCFF, and SciPCFF, were separately assigned to model the LCE system, and their suitability was validated through experimental results. Among these selected force fields, the SciPCFF produced the best agreement with the experimentally measured thermal and viscoelastic properties compared to those of simulated steady-state density, transition temperature, and viscoelastic characteristics. Next, shape fixity (Rf) and shape recovery (Rr) of LCEs were estimated using this force field. A four-step simulated shape memory procedure proceeded under a tensile mode. The changes in molecular conformations were calculated for Rf and Rr after the unloading step and the reheating step. The results revealed that the model LCE system exhibits characteristic behaviors of Rf and Rr over the thermomechanical shape memory process, confirming the suitability of selected force field for use in the design and prediction of properties of typical LCE class of polymers.
First-principle study of the structures, growth pattern, and properties of (Pt3Cu)n, n = 1–9, clusters
Authors: Galindo-Uribe Carlos Daniel , Calaminici Patrizia , Cruz-Martínez Heriberto , Cruz-Olvera Domingo , Solorza-Feria Omar
Published: April 2021

In this work, a first-principles systematic study of (Pt3Cu)n, n = 1–9, clusters was performed employing the linear combination of Gaussian-type orbital auxiliary density functional theory approach. The growth of the clusters has been achieved by increasing the previous cluster by one Pt3Cu unit at a time. To explore in detail the potential energy surface of these clusters, initial structures were obtained from Born–Oppenheimer molecular dynamics trajectories generated at different temperatures and spin multiplicities. For each cluster size, several dozens of structures were optimized without any constraints. The most stable structures were characterized by frequency analysis calculations. This study demonstrates that the obtained most stable structures prefer low spin multiplicities. To gain insight into the growing pattern of these systems, average bond lengths were calculated for the lowest stable structures. This work reveals that the Cu atoms prefer to be together and to localize inside the cluster structures. Moreover, these systems tend to form octahedra moieties in the size range of n going from 4 to 9 Pt3Cu units. Magnetic moment per atom and spin density plots were obtained for the neutral, cationic, and anionic ground state structures. Dissociation energies, ionization potential, and electron affinity were calculated, too. The dissociation energy and the electron affinity increase as the number of Pt3Cu units grows, whereas the ionization potential decreases.