bluuebunny/crossref_metadata_2025 huggingface dataset:
Crystal structure and thermodynamic properties of dinickel diphosphate dihydrate Ni2(H2O)2[P2O7]
Authors: Kiriukhina Galina V. , Yakubovich Olga V. , Shvanskaya Larisa V. , Ovchenkov Yevgeniy A. , Volkov Anatoly S. , Dimitrova Olga V. , Simonov Sergey V. , Vasiliev Alexander N.
Published: November 2020

The Ni member of the Me2(H2O)2[P2O7]2 family demonstrates antiferromagnetic ground states and sequences of spin–flip and spin–flop phase transitions.
Visible-light-mediated semi-heterogeneous black TiO2/nickel dual catalytic C (sp2)–P bond formation toward aryl phosphonates
Authors: Koohgard Mehdi , Karimitabar Haniehsadat , Hosseini-Sarvari Mona
Published: November 2020

The combination of black TiO2 nanoparticles (NPs) with a nickel catalyst provides a low-cost, sustainable, and reusable alternative photoredox/nickel system to a homogeneous counterpart (noble metals) in C(sp2)−P coupling reaction.
Proton transfer vs. oligophosphine formation by P–C/P–H σ-bond metathesis: decoding the competing Brønsted and Lewis type reactivities of imidazolio-phosphines
Authors: Cicač-Hudi Mario , Feil Christoph M. , Birchall Nicholas , Nieger Martin , Gudat Dietrich
Published: November 2020

Cationic imidazolio-phosphines show two-sided reactivity towards bases, undergoing either Brønsted-type proton transfer to imidazolio-phosphides or autocatalytic Lewis acid/base reaction cascades to yield P-free imidazolium ions and oligophosphines.
Recent advances in the synthesis of organophosphorus compounds via Kobayashi's aryne precursor: a review
Authors: Neog Kashmiri , Gogoi Pranjal
Published: November 2020

This review systematically summarizes the progress in aryne chemistry for the synthesis of organophosphorus compounds via aryne insertion into the C–P, P–N, P–P, P–O, PP, PN and PS bonds.
Synthesis of 5-substituted tetrazolesviaDNA-conjugated nitrile
Authors: Du Huang-Chi , Matzuk Martin M. , Chen Ying-Chu
Published: November 2020

The development of DNA-compatible synthesis of 5-substituted tetrazoles.
Towards synergistic oscillations in enzymatically active hydrogel spheres
Authors: Bell Daniel Josef , Felder Daniel , von Westarp William Graf , Wessling Matthias
Published: November 2020

We report the synthesis of self-regulated, enzymatically active, and pH-responsive hydrogels that show dynamic behavior without an external trigger.
High-rate cathode CrSSe based on anion reactions for lithium-ion batteries
Authors: Yang Si-Yu , Shi Ding-Ren , Wang Tian , Yue Xin-Yang , Zheng Lei , Zhang Qing-Hua , Gu Lin , Yang Xiao-Qing , Shadike Zulipiya , Li Hong , Fu Zheng-Wen
Published: November 2020

CrSSe is a novel layered electrode material based on anionic reactions of S and Se. And a new type of lithium-ion battery is fabricated when paired with soft carbon, in which Li3N film was in situ generated on the electrode surface as the sole lithium source.
The rational doping of P and W in multi-stage catalysts to trigger Pt-like electrocatalytic performance
Authors: Du Yunmei , Wang Wensi , Zhao Huimin , Liu Yanru , Li Shaoxiang , Wang Lei
Published: November 2020

Motivated by the synergistic incorporation of W and P, the 2H-phase MoS2 with limited edge active sites was partially converted into highly active 1T-phase MoS2 with rich defects.
Speech-Language Therapy Experiences Across the Life Span of an Individual Who Covertly Stutters: A Thematic Analysis
Authors: Douglass Jill E. , Kennedy Catherine , Smith Kaitlyn
Published: November 2020

Purpose

The current research study investigates the speech therapy experiences of an individual who covertly stuttered for approximately 40 years; at the time of the interview, she was in her mid-40s.

Method

The single-case study is a qualitative thematic analysis of the speech therapy experiences of one individual across her life span. In addition to her stuttering, the participant lives with a significant primary diagnosis that she has had since birth, which impacts her activities in daily living. Interview questions were open-ended and conducted via Skype. The interview was transcribed, and a thematic analysis of the recorded transcripts was conducted to investigate her experiences in speech therapy as an individual who covertly stutters.

Findings

The current findings reveal five major themes regarding the speech therapy experiences of an individual who covertly stutters: (a) nonindividualized treatment and goals, (b) blaming and shaming associated with speech therapy and stuttering, (c) positive self-regard during speech therapy attendance, (d) the use of avoidance strategies and relation to speech therapy, and (e) the evolution of therapy goals. Direct quotations from the participant are used to support these themes.

Discussion

The significant impact of covert stuttering on an individual is discussed. Results from the participant's experiences indicate an essential need to conduct individualized speech therapy for people who stutter. Speech-language pathologists and others working with persons who stutter maintain a responsibility to recognize the role that case history and counseling play in order to appropriately serve people who covertly stutter.
Re-Imagining Community-Engaged Learning: Service-Learning in Communication Sciences and Disorders Courses During and After COVID-19
Authors: Veyvoda Michelle A. , Van Cleave Thomas J.
Published: November 2020

Purpose

Community-engaged learning, often practiced through service-learning pedagogy, has been shown to have numerous benefits for both students and communities in communication sciences and disorders undergraduate and graduate programs. While service-learning typically involves students applying their knowledge and learned skills to help satisfy an expressed community need, the recent shift to online learning combined with shuttered community partner organizations may make some practitioners hesitant to pursue the pedagogy. This tutorial reviews the literature on service-learning, its use in online learning, and ways in which faculty in higher education can re-imagine and prioritize community engagement during and after the COVID-19 pandemic.

Conclusions

Continued community-engaged learning, whether through virtual, hybrid, or in-person practice, is still an essential component of a liberal education that can help students practice clinical skills, develop cultural humility and cross-cultural knowledge, gain an understanding of social inequities and health care disparities, and build positive relationships with their community. There are ways for faculty to re-imagine service-learning course delivery in order to maintain the virtues of higher education, sharpen clinical skills, and develop civic engagement among students.
Beamforming and combining for multi‐user large MIMO communication system
Authors: M.K. Arti , Rani Pratibha , Dimri Pradeep Kumar , Vashishath Munish
Published: November 2020

A beamforming and combining method for a multi‐user large multiple‐input multiple‐output (MIMO) system is proposed, in this study. A transmitter is equipped with a very large number of antennas to serve many users. At the transmitter, a group of antennas is allocated to each user. For a particular group of antennas, a specific beamforming vector is employed at the transmitter for transmission of a signal of a specific user. At the user end, a distinct combining vector is utilised for detecting the transmitted signal. In the proposed scheme, first, the interference due to unwanted signals of undesired users is nullified by using the concept of null space. Then the method of maximum ratio transmission is used to calculate the beamforming vector. The calculation of combining vector depends upon the maximum eigenvalue criterion. The analytical performance of the proposed method is discussed in terms of symbol error rate (SER). An expression of SER is derived by using the moment generating function approach. It is shown by simulations and analysis that the proposed scheme performs better if more antennas are equipped either at the transmitter or users.
Efficient pilot design scheme for OFDM‐based full‐duplex systems
Authors: Zhou Juan , Shen Ying , Li Li , Xue Ya‐Juan
Published: November 2020

In orthogonal frequency‐division multiplexing (OFDM)‐based full‐duplex (FD) systems, the terminal is allowed to transmit and receive signals simultaneously in the same frequency band. This leads to new challenges to pilot for channel estimation. The conventional pilot design methods are no longer effective for such systems. In this study, the authors propose a new practical pilot design method for OFDM‐based FD systems and its performance is analysed in terms of the self‐interference cancellation capability. Unlike the existing OFDM‐based FD pilot design schemes, which require the channel to be constant during multiple continuous OFDM symbols, the authors' proposed scheme can be implemented in the block fading channel (i.e. channels that vary from one OFDM symbol to another). Besides, the optimal pilot pattern of the proposed scheme is studied. Their simulation results demonstrate the efficiency of the proposed pilot design.
Consumer appliance‐level load shedding optimisation for real‐time application
Authors: Jabian Marven E. , Funaki Ryohei , Murata Junichi
Published: November 2020

Load shedding (LS) is implemented by distribution utilities (DUs) in addressing power supply insufficiency problems to avoid DU system damages. This is commonly implemented by the installation of LS relays in every DU feeder. However, in either scheduled or unscheduled supply disruptions, a huge amount of unnecessary de‐loading is taking place in a feeder level LS implementation. In addition, the consumers connected to a de‐loaded feeder are in total blackout, that is, consumers have no choice over which appliances to spare from being de‐loaded. This study proposes an LS implementation that replaces feeder‐level de‐loading by a finer consumer‐appliance‐level de‐loading and allows consumers to have some control over their de‐loading. In this method, consumers can set an appliance priority level to their selected connected loads at a given time, to avoid a total blackout. Furthermore, to deal with the enormous data involved in this proposed method, both centralised and distributed optimisation approaches are employed to expedite the system processing response. Simulations are conducted to verify the proposed method's functionality. Lastly, economic analysis is done to assess the proposed method's viability.
APEX-SEPIA660 Early Science: gas at densities above 107 cm−3 towards OMC-1
Authors: Hacar A. , Hogerheijde M. R. , Harsono D. , Portegies Zwart S. , De Breuck C. , Torstensson K. , Boland W. , Baryshev A. M. , Hesper R. , Barkhof J. , Adema J. , Bekema M. E. , Koops A. , Khudchenko A. , Stark R.
Published: November 2020

Context. The star-formation rates and stellar densities found in young massive clusters suggest that these stellar systems originate from gas at densities of n(H2) > 106 cm−3. Until today, however, the physical characterization of this ultra high density material remains largely unconstrained in observations.

Aims. We investigate the density properties of the star-forming gas in the OMC-1 region located in the vicinity of the Orion Nebula Cluster (ONC).

Methods. We mapped the molecular emission at 652 GHz in OMC-1 as part of the APEX-SEPIA660 Early Science.

Results. We detect bright and extended N2H+ (J = 7–6) line emission along the entire OMC-1 region. Comparisons with previous ALMA data of the (J = 1–0) transition and radiative transfer models indicate that the line intensities observed in this N2H+ (7–6) line are produced by large mass reservoirs of gas at densities n(H2) > 107 cm−3.

Conclusions. The first detection of this N2H+ (7–6) line at parsec-scales demonstrates the extreme density conditions of the star-forming gas in young massive clusters such as the ONC. Our results highlight the unique combination of sensitivity and mapping capabilities of the new SEPIA660 receiver for the study of the ISM properties at high frequencies.
The reduced proper motion selected halo: Methods and description of the catalogue
Authors: Koppelman Helmer H. , Helmi Amina
Published: November 2020

Context. The Gaia mission has provided the largest ever astrometric chart of the Milky Way. Using it to map the Galactic halo is helpful for disentangling its merger history.

Aims. The identification of halo stars in Gaia DR2 with reliable distance estimates requires special methods because such stars are typically farther away and scarce.

Methods. We applied the reduced proper motion method to identify halo main sequence stars on the basis of Gaia photometry and proper motions. Using the colour-absolute-magnitude relation for this type of star, we calculated photometric distances. Our selection results in a set of ∼107 tentative main sequence halo stars with typical distance uncertainties of 7% and with median velocity errors of 20 km s−1. The median distance of our sample is ∼4.4 kpc, with the faintest stars located at ∼16 kpc.

Results. The spatial distribution of the stars in our sample is centrally concentrated. A visual inspection of the mean velocities of stars on the sky reveals large-scale patterns as well as clear imprints of the GD-1 stream and tentative hints of the Jhelum and Leiptr streams. Incompleteness and selection effects limit our ability to interpret the patterns reliably as well as to identify new substructures. We define a pseudo-velocity space by setting the line-of-sight velocities of our sample stars to zero. In this space, we recover several known structures such as the footprint of Gaia-Enceladus (i.e., the Gaia-Sausage) as well as the Helmi Streams and some other retrograde substructures (Sequoia, Thamnos). We show that the two-point velocity correlation function reveals significant clustering on scales smaller than 100 km s−1 of a similar amplitude as found for the 6D Gaia halo sample. This clumping of stars in velocity space might hint at the presence of nearby streams that are predominantly phase-mixed.

Conclusions. A spectroscopic follow-up of our halo main sequence sample is bound to yield unprecedented views of Galactic history and dynamics. In future Gaia data releases, the level of systematics will be reduced and the astrometry will be more precise, which will allow for the identification of more substructures at larger distances.
Accretion bursts in magnetized gas-dust protoplanetary disks
Authors: Vorobyov Eduard I. , Khaibrakhmanov Sergey , Basu Shantanu , Audard Marc
Published: November 2020

Aims. Accretion bursts triggered by the magnetorotational instability (MRI) in the innermost disk regions were studied for protoplanetary gas-dust disks that formed from prestellar cores of a various mass Mcore and mass-to-magnetic flux ratio λ.

Methods. Numerical magnetohydrodynamics simulations in the thin-disk limit were employed to study the long-term (~1.0 Myr) evolution of protoplanetary disks with an adaptive turbulent α-parameter, which explicitly depends on the strength of the magnetic field and ionization fraction in the disk. The numerical models also feature the co-evolution of gas and dust, including the back-reaction of dust on gas and dust growth.

Results. A dead zone with a low ionization fraction of x≲10−13 and temperature on the order of several hundred Kelvin forms in the inner disk soon after its formation, extending from several to several tens of astronomical units depending on the model. The dead zone features pronounced dust rings that are formed due to the concentration of grown dust particles in the local pressure maxima. Thermal ionization of alkaline metals in the dead zone trigger the MRI and associated accretion burst, which is characterized by a sharp rise, small-scale variability in the active phase, and fast decline once the inner MRI-active region is depleted of matter. The burst occurrence frequency is highest in the initial stages of disk formation and is driven by gravitational instability (GI), but it declines with diminishing disk mass-loading from the infalling envelope. There is a causal link between the initial burst activity and the strength of GI in the disk fueled by mass infall from the envelope. We find that the MRI-driven burst phenomenon occurs for λ = 2–10, but diminishes in models with Mcore ≲ M⊙, suggesting a lower limit on the stellar mass for which the MRI-triggered burst can occur.

Conclusions. The MRI-triggered bursts occur for a wide range of mass-to-magnetic flux ratios and initial cloud core masses. The burst occurrence frequency is highest in the initial disk formation stage and reduces as the disk evolves from a gravitationally unstable to a viscous-dominated state. The MRI-triggered bursts are intrinsically connected with the dust rings in the inner disk regions, and both can be a manifestation of the same phenomenon, that is to say the formation of a dead zone.
L'enveloppe solaire : un retour vers le futur
Authors: Koubaa Turki Laila , Raboudi Khaoula , Ben Saci Abdelkader
Published: November 2020

Cet article propose un retour réflexif sur le modèle de l’enveloppe solaire. Il s’agit d’un regard rétrospectif des approches numériques de ce modèle qui se voulait dès le départ servir l’activité de conception. Le développement des modèles de calcul énergétique a permis d’affiner la détermination de ses contraintes. L’avancée numérique a donné lieu à des enveloppes dérivées intégrant, en plus de l’accès solaire, des paramètres physiques ou réglementaires. Cependant, l’avancée numérique de l’enveloppe solaire n’est pas utilisée pour répondre aux défis climatiques actuels. Ce papier propose de dresser un état de l'art de l'enveloppe solaire, de ses développements et de ses applications en vue de comprendre en quoi la promesse des années soixante-dix est aujourd’hui réaliste. C’est l’occasion aussi de discuter le rôle que joue le progrès scientifique et technique de la morphose numérique dans les pratiques architecturales et urbaines.
Relire la pensée de Frei Otto sur l’espace et les formes à la lumière du numérique (et réciproquement)
Authors: Corcuff Marie-Pascale
Published: November 2020

Frei Otto a toute sa vie expérimenté sur l’espace et les formes, à travers des expériences de pensée ou des dispositifs matériels. Son attitude rejoint celle qui préside à l’écriture d’algorithmes génératifs et la confrontation des deux démarches s’avère stimulante pour l’imagination créatrice. Cet aller-retour est illustré à travers trois cas d’étude qui concernent la délimitation de territoires, les forces de distanciation/attraction, et enfin les chemins optimisés.
Quand l’ordinateur devient générateur de forme – Retour sur l’expérience duFractal Studio
Authors: Bourbonnais Sébastien
Published: November 2020

En 1987 s’est tenu leFractal Studioqui a permis la rencontre entre Chris I. Yessios et Peter Eisenman et qui peut certainement être considéré comme un moment clé dans le changement des mentalités par rapport au rôle à accorder à l’informatique dans les pratiques architecturales. Afin de comprendre ce basculement, il sera présenté, au travers des recherches de Yessios, quelques-uns des enjeux de la conception assistée par ordinateur au tournant des années 80, comme l’opposition entre la projection orthogonale et la modélisation volumétrique. Pour leFractal Studiola question comment représenter un édifice ne sera plus centrale mais, à partir de l’exploration de certains processus, dont ceux des fractals, l’ordinateur a été pensé comme un générateur de formes qui permettait de « renforcer » la créativité. Ce nouveau rôle accordé à l’ordinateur a entrainé dans son sillage une série d’explorations formelles qui ont pris avec sérieux l’idée d’une possible refonte de l’architecture, dont les épisodes de la deconstruction (1988) et du pliage (1993) ont cherché à définir une nouvelle architecture. La question que nous souhaiterions soumettre dans le cadre de ce colloque est que se serait-il passé si la déconstruction n’avait pas eu lieu ?
Modélisation Paramétrique en Réalité Virtuelle
Authors: Coppens Adrien , Mens Tom , Gallas Mohamed-Anis
Published: November 2020

Les technologies immersives ont fait leur apparition dans bon nombre d’outils de modélisation architecturale. Néanmoins, leur usage se limite bien souvent à des fins de visualisation, par exemple pour valider un design auprès d’un client muni d’un casque de réalité virtuelle. Notre travail vise à permettre une utilisation de ce medium immersif durant l’activité de conception architecturale elle-même. Nous présentons dès lors un outil de modélisation paramétrique en réalité virtuelle permettant de combiner, en immersion, l’édition de modèles Grasshopper et la visualisation des géométries générées. Nous validerons notre approche auprès d’architectes et d’étudiants formés à ce paradigme de conception.
Antegrade anterior column screw placement in the lateral decubitus position utilizing an axial view: a technical trick
Authors: Vaidya Rahul , Patel Ishan , Simmons Katelyn , Nasr Kerellos , Washington Austen
Published: November 2020

The placement of anterior column screws is a useful procedure and has standard views when placing this screw in the supine position. Feng et al. described an acetabular anterior column axial view for patients in the supine position for a placement of a retrograde anterior column screw [J Orthop Surg (Hong Kong) 25, 2309499016685012]. However, many acetabular fracture surgeries are performed in the lateral decubitus position due to a variety of reasons. Placing an antegrade anterior column screw in this position is difficult due to an unfamiliarity of the optimal fluoroscopic images. The purpose of this article is to describe a novel technique to obtain appropriate imaging to safely place an anterior column screw while the patient is in the lateral decubitus position.
Intersecting Vulnerabilities: The Impacts of COVID-19 on the Psycho-emotional Lives of Young People in Low- and Middle-Income Countries
Authors: Banati Prerna , Jones Nicola , Youssef Sally
Published: November 2020

Across diverse contexts, emerging evidence suggests that the COVID-19 pandemic is increasing levels of anxiety and stress. In calling for greater attention to people’s psychosocial and emotional well-being, global actors have paid insufficient attention to the realities of the pandemic in low- and middle-income countries, where millions of people are already exposed to intersecting vulnerabilities. Chronic poverty, protracted violence, conflict and displacement, coupled with weak health, education and protection systems, provide the backdrop of many adolescents’ lives. Drawing on qualitative in-country telephone interviews with over 500 adolescents in Ethiopia, Côte d’Ivoire and Lebanon, this article unpacks the age and gendered dimensions of COVID-19 and its response. We conclude by discussing the implications for COVID-19 recovery efforts, arguing that embedding adolescent-centred, inclusive approaches in education, community-based health and social protection responses, has the potential to mitigate the psycho-emotional toll of the pandemic on young people and promote resilience.
A typology of healthcare interpreter positionings
Authors: René de Cotret François , Brisset Camille , Leanza Yvan
Published: November 2020

The conceptual vagueness surrounding the role of the public service interpreter can hinder collaboration between
interpreters and providers. Inspired by Mason’s work on interpreter positioning, the study aimed to clarify providers’ expectations of the
role of the interpreter in order to strengthen interprofessional collaboration. A typological analysis was conducted based on 23 healthcare
providers’ perceptions of the public service interpreter. The Typology of Healthcare Interpreter Positionings features eight positionings
that reinforce the interprofessional collaboration and nine that compromise it. The result is a concrete portrait that depicts the
neutrality of the public service interpreter as a powerful driver of collaboration. Providers also agree that interpreters must be able to
take their place in the consultation, even if it means being assertive and modifying the discourse of the interlocutors. Navigating such
situations while maintaining the provider’s trust requires interactional knowledge (soft skills), which complements technical knowledge
(hard skills). The Typology represents a communication tool that both providers and interpreters can use to foster collaboration. It also
represents a professionalization tool as it reiterates the importance of neutrality in the work of public service interpreters and their
social positioning as professionals.
Incoming Medical Students’ Knowledge of and Attitudes Toward People with Substance use Disorders: Implications for Curricular Training
Authors: Moses Tabitha E. , Chammaa May , Ramos Rafael , Waineo Eva , Greenwald Mark K.
Published: November 2020

Background

Medical students may be in an ideal position to identify patients with substance use disorders (SUDs) and provide them with information about harm reduction and treatment options. Specific education regarding opioid use disorder (OUD) and naloxone during undergraduate medical training may help students identify these patients and decrease their own negative attitudes toward patients with OUD. To plan for curriculum development, this study aimed to understand baseline knowledge and attitudes among students entering medical school.

Methods

During orientation, all first-year medical students (Class of 2023) were asked to complete a survey that explored their previous experiences in healthcare and with SUDs as well as their attitudes toward opioid overdose and patients with SUDs. We administered the Opioid Overdose Knowledge Scale (OOKS), Opioid Overdose Attitudes Scale (OOAS), Medical Conditions Regard Scale (MCRS), and Naloxone Related Risk Compensation Beliefs (NaRRC-B).

Results

266 students (89.6% of the class) completed the survey. Generally, these students were relatively proficient in opioid overdose knowledge, but did not feel they were competent enough to respond to an overdose. Attitudes toward patients with SUDs were mixed. Approximately half of the students thought naloxone distribution should be unrestricted, but many were uncertain whether naloxone receipt would deter individuals from seeking treatment or increase opioid use. Students’ previous experiences in healthcare (e.g., employment) results in significantly different knowledge and attitudes toward opioid overdose response.

Conclusions

These incoming medical students have greater healthcare experience and level of opioid overdose knowledge than the general population, but still harbor significant misinformation and stigma toward patients with SUDs. These findings provide a foundation upon which to tailor didactic efforts, starting early in medical school, so that graduating physicians can be adequately prepared for clinical care.
Neoliberalism, welfare, and mass male circumcisions in Turkey
Authors: Başaran Oyman
Published: November 2020

This article explores the neoliberalization of mass male circumcisions, a type of social assistance in Turkey. Male circumcision is a religious and medical practice widely performed in Muslim-majority Turkey, and when this procedure is organised for the poor in large numbers, it is referred to as mass male circumcisions. The article argues that since the 2000s, the AKP (Justice and Development Party) has neoliberalized mass male circumcision by transforming it into an economic and symbolic resource for competing hospitals as well as shaping the ‘deserving’ urban poor families into consumer-like actors. The article further shows the limits and contradictions of this process. In doing so, it challenges the binary between neoliberalism and welfare, and views social assistance as another potential site of neoliberalization that recrafts the society and the state in the image of the market, cutting across economic and non-economic spheres.
Manifold properties from causal sets using chains
Authors: Kambor Joachim , X Nomaan
Published: November 2020

We study the utility of chains defined on causal sets in estimating continuum properties like the curvature, the proper time and the spacetime dimension through a numerical analysis. In particular, we show that in dS
2 and FLRW3 spacetimes the formalism of Roy M et al 2013 Phys. Rev. D
87 044046 with slight modifications gives the right continuum properties. We also discuss a possible test of manifoldlikeness using this formalism by considering two models of non-manifoldlike causal sets. This is a part of a broader idea of the geometrical reconstruction of continuum properties given a discrete sub structure, in this case the causal set.
A connection between the ice-type model of Linus Pauling and the three-color problem
Authors: da Silva Roberto , Nakao Osvaldo S , de Felício J R Drugowich
Published: November 2020

The ice-type model proposed by Linus Pauling to explain its entropy at low temperatures is here approached in a didactic way. We first present a theoretically estimated low-temperature entropy and compare it with numerical results. Then, we consider the mapping between this model and the three-colour problem, i.e. colouring a regular graph with coordination equal to 4 (a two-dimensional lattice) with three colours, for which we apply the transfer-matrix method to calculate all allowed configurations for two-dimensional square lattices of N oxygen atoms ranging from 4 to 225. Finally, from a linear regression of the transfer matrix results, we obtain an estimate for the case N → ∞ which is compared with the exact solution by Lieb.
Ultrasound modulated bioluminescence tomography with a single optical measurement
Authors: Chung Francis , Yang Tianyu , Yang Yang
Published: November 2020

Ultrasound modulated bioluminescence tomography is an imaging method which can be formulated as a hybrid inverse source problem. In the regime where light propagation is modeled by a radiative transfer equation, previous approaches to this problem require large numbers of optical measurements (Bal et al 2016 SIAM J. Math. Anal.
48 1332). Here we propose an alternative solution for this inverse problem which requires only a single optical measurement in order to reconstruct the isotropic source. Specifically, we derive two inversion formulae based on Neumann series and Fredholm theory respectively, and prove their convergence under sufficient conditions. The resulting numerical algorithms are implemented and experimented to reconstruct both continuous and discontinuous sources in the presence of noise.
On topological classification of Morse–Smale diffeomorphisms on the sphere S

n
(n > 3)
Authors: Grines V , Gurevich E , Pochinka O , Malyshev D
Published: November 2020

We consider the class G(S

n
) of orientation preserving Morse–Smale diffeomorphisms of the sphere S

n
of dimension n > 3, assuming that invariant manifolds of different saddle periodic points have no intersection. For any diffeomorphism f ∈ G(S

n
), we define a coloured graph Γ
f
that describes a mutual arrangement of invariant manifolds of saddle periodic points of the diffeomorphism f. We enrich the graph Γ
f
by an automorphism P

f
induced by dynamics of f and define the isomorphism notion between two coloured graphs. The aim of the paper is to show that two diffeomorphisms f, f′ ∈ G(S

n
) are topologically conjugated if and only if the graphs Γ
f
, Γ
f
′ are isomorphic. Moreover, we establish the existence of a linear-time algorithm to distinguish coloured graphs of diffeomorphisms from the class G(S

n
).
Full thermal characterization of AlGaN/GaN high electron mobility transistors on silicon, silicon carbide, and diamond substrates using a reverse modeling approach
Authors: El-Helou A , Cui Y , Tadjer M J , Anderson T J , Francis D , Feygelson T , Pate B , Hobart K D , Raad P E
Published: November 2020

Gallium nitride (GaN) high electron mobility transistors (HEMTs) operate at high power levels and are thus especially thermally-critical devices. Not only do they require innovative thermal management strategies, but can also benefit from advanced experimental thermal characterization, both numerical and experimental, in their design and system integration stages. The thermal numerical analysis of microelectronic devices faces the challenges of complex physics and uncertain thermophysical properties which leads to numerically expensive models that are prone to error. By the use of an innovative reverse modeling approach to mitigate the above challenges, this work presents the full thermal characterization of GaN power devices with different substrates aimed at managing performance-limiting self-heating. The approach develops and optimizes a thermal simulation model to match the numerical results to experimentally-obtained thermal maps of the devices under test. The experimentally-optimized simulation model can then be used to extract full 3D temperature distributions, infer in-situ thermal properties, and provide a numerical platform that can be used to conduct further parametric studies and design iterations. The presented analysis provides a full thermal characterization of different GaN HEMT devices and compares the thermal performance of different substrates on the basis of thermal properties. The extracted properties for HEMTs on Si, SiC, and Diamond substrates are compared and a set of conclusions are presented to guide further developments in GaN HEMT thermal management strategies.
A high-efficiency energy regeneration shock absorber based on twin slider-crank mechanisms for self-powered sensors in railway cars
Authors: Li Lingbo , Wang Wei , Luo Dabing , Zhang Zutao , Qi Lingfei , Xie Li
Published: November 2020

In recent years, with the rapid increase of railway freight, various types of self-powered sensors have been widely used in intelligent electronic monitoring equipment and on-board electric equipment in order to improve the safety and transportation efficiency of railway freight during operation. In this paper, a type of energy regeneration shock absorber based on twin slider-crank mechanisms is developed to install on the auxiliary suspensions of railway cars parallel to the coil springs. The energy regeneration shock absorber is divided into four components, as follows: a suspension vibration energy input module, a transmission module, a generator module, and an energy storage module. The suspension vibration energy input module captures the vibration energy generated by the railway car suspension. The transmission module converts the linear motion of the shock absorber into the one-way rotation motion of the generator input shaft to generate electrical energy. The energy storage module stores the electricity in the super capacitor to supply energy to self-powered sensors in railway cars. According to the bench test of the MTS® fatigue testing system, the peak efficiency of the shock absorber is 56.4%, and the average efficiency is 42.9%. Under harmonic excitation with a frequency of 3 Hz and an amplitude of 12.5 mm, the peak phase power is 24.6 W and the average power is 4.8 W, showing that the proposed new energy regeneration shock absorber is effective and practical to apply to self-powered sensors in railway cars.
T
cs degradation of ITER TF samples due to fast current discharges
Authors: Sedlak Kamil , Bruzzone Pierluigi , Stepanov Boris , Mitchell Neil , Tronza Vladimir , Vostner Alexander
Published: November 2020

Direct current tests performed in the past on the conductor samples of the toroidal field (TF) ITER coils revealed degradation of current sharing temperature, T
cs. The degradation progresses with repetitive electromagnetic loading, and also with thermal cycles between 4.5 K and room temperature. This feature was observed on short samples in SULTAN test facility (EPFL-SPC, Switzerland) as well as in TF Insert Coil tests in CSMC test facility (Naka, Japan). We present three independent observations suggesting that initiation of sample quench followed by a fast current discharge, which normally complements every I
c and T
cs test in both SULTAN and CSMC, enhances the T
cs degradation rate. The exact mechanism of this contribution to the degradation remains unidentified.
Influence of strain-driven segregation in low-angle grain boundaries on critical current density of Y0.9Nd0.1Ba2Cu3O7-d
Authors: Kim Sang-il , Larbalestier David C
Published: November 2020

Low-angle grain boundaries (GBs) constitute the most important current-limiting mechanism in the operation of biaxially textured YBa2Cu3O7−d (YBCO)-coated conductors. Ca doping of YBCO is known to improve the critical current density J
c across the GB because of carrier doping by anisovalent Ca2+ substitution for Y3+ and the strain relief induced by Ca segregation at the GB cores; however, the reduction of the superconducting critical temperature T
c accompanying such doping is a marked drawback. Here we study the substitution of isovalent Nd3+ for Y3+ again using strain-driven segregation, in this case Nd3+, to improve J
c without incurring significant T
c reduction. Transport characteristics of low-angle GBs of 10% Nd-doped YBCO, Y0.9Nd0.1Ba2Cu3O7−d, grown on single crystal and 6° and 9° [001] tilt symmetric bicrystal SrTiO3 substrates are reported. It was found that J
c across the 6° GB recovers to the intra-grain J
c value in the 10% Nd-doped YBCO, while the 9° GB shows a modest J
c enhancement compared to the pure YBCO 9° GB without a significant T
c reduction. It is shown that the transparency of the GB could be enhanced without a large T
c reduction by the isovalent substitution of rare-earth ions, suggesting new opportunities for cation segregation engineering in YBCO by isovalent rare-earth substitution.
Optimum heat treatment to enhance the weak-link response of Y123 nanowires prepared by Solution Blow Spinning
Authors: Caffer Ana M , Chaves Davi A D , Pessoa Alexsander L , Carvalho Claudio L , Ortiz Wilson A , Zadorosny Rafael , Motta Maycon
Published: November 2020

Although the production of YBa2Cu3O7-δ (Y123) has been extensively reported, there is still a lack of information on the ideal heat treatment to produce this material in the form of one dimension nanostructures. Thus, by means of the Solution Blow Spinning technique, metals embedded in polymer fibers were prepared. These polymer composite fibers were fired and then investigated by thermogravimetric analysis. The maximum sintering temperatures of heat treatment were chosen in the interval 850 °C–925 °C for 1 h under oxygen flux. SEM images allowed us to determine the wire diameter as approximately 350 nm for all samples, as well as to map the evolution of the entangled wire morphology with the sintering temperature. XRD analysis indicated the presence of Y123 and secondary phases in all samples. Ac magnetic susceptibility and dc magnetization measurements demonstrated that the sample sintered at 925 °C/1 h is the one with the highest weak-link critical temperature and the largest diamagnetic response.
Research on the pricing of the double-competition closed-loop supply chain with uncertain recycling quantity
Authors: Han Mei , Liu Xiaowei
Published: November 2020

In order to solve the uncertainty impact of recycled products on pricing decision-making and financial intervention policy in double competition closed-loop supply chain, a pricing decision-making model is built by using the game theory and MATLAB numerical simulation. The model analyses and verifies the impact of the uncertain quantity upon the competition intensity, sale and recycling prices, supply chain node companies’ profits and social welfare, recovery rate of the closed-loop supply chain from four dimensions. The research results show that the recycling and repurchase prices are increasing when the quantity of recycled products shows significant fluctuation. The profit of social welfare and sellers are increasing, but manufacturer’s profit is decreasing, which means the uncertainty on recovery quantity directly affects the manufacturers, who play a leading role in implementing remanufacturing.
A new construction algorithm of the digital economy innovation system
Authors: Zhai Zhengang , Wu Nannan , Zhu Yunya , Gao Bingtao , Pan Zhiyuan
Published: November 2020

To effectively promote the development of digital economy, we have proposed a new construct algorithm of digital economy innovation system. It mainly researches four indicators: innovation subject, innovation resources, innovation efficiency and innovation environment. The quality synthesis index of digital economy development in recent years is calculated through the entropy method. To further analyse the main factors affecting the development quality, the grey relation analysis method is adopted. Besides, the grey prediction model is established to predict the future development trend of digital economy. Based on the data collected from Jiaxing Statistics Bureau from 2010 to 2018, we find that its overall development is growing year by year, in which the innovation efficiency contributes the most, and it is closely related to the innovation resources and environment, but there is still an uneven development among the indicators. The research is conducive to promoting the development of the digital economy and helping to build a modern industrial system for the digital economy.
Research on observation data compression of hydraulic engineering based on swinging door trending algorithm
Authors: Liu Lihuan , Ceng Jiang , Gu Chunhui
Published: November 2020

With the wide application of big data technology, there is a geometric series increase of the real-time data collection of water conservancy engineering, which causes a large number of storage units and memory. In order to make the huge amount of data easy to collect and process, an improved Swinging Door Trending algorithm is proposed to compress the data of water conservancy project based on the deep research of data compression algorithm. This work firstly analyzed the collected abnormal points, which identified and processed the points in time to realize the timely alarm of abnormal conditions according to the characteristics of water conservancy engineering data and acquisition requirements; then discussed the dynamic adjustment of tolerance, which is carried out according to the fluctuating state of water conservancy engineering data to store less real-time data; and finally put forward that the improved SDT algorithm has higher compression ratio and better compression efficiency than the traditional SDT method does by experiments.
An intelligent diversion method for tourists in scenic spots based on behavioral characteristics
Authors: Li Wenqing
Published: November 2020

This paper focused on the problem of time-space diversion and navigation of tourists in scenic spots. Through the analysis and research on the three major behavior characteristics of tourists in scenic spots, namely, the characteristics of recreation direction, the characteristics of recreation speed and the characteristics of recreation time, a method of real-time diversion with minimum cost is proposed, and an intelligent diversion model based on “behavior characteristics” is constructed Guilin Qixing scenic spot is used as an example for analysis and test. The test results show that the intelligent diversion model can effectively guide tourists to the scenic spots with the shortest waiting time and solve the problem of uneven load on each scenic spot. Through the scientific diversion design in time and space, it can not only improve the satisfaction of tourists, but also help the scenic spot personnel to grasp the use of resources in the scenic spot at any time, improve the quality of normalized management of scenic spots, and provide a theoretical and practical basis for the further development of smart Tourism in major scenic spots.
Design of motor state monitoring system based on cloud
Authors: Jia Weiwei , Li Meifeng , Wang Pengwei
Published: November 2020

Most of the intelligent motor monitoring protectors on the market can only carry out local monitoring, but can’t achieve cloud data monitoring, such as no remote data query, no remote control, limited data storage, etc. This article was based on a variety of sensor module and cellular data communication module to form a complete monitoring system, the clouds could accurately and quickly detect the voltage, current, rotate speed and temperature of the motor, and upload data to the cloud platform, to realize remote data query and monitoring, the system was simple in structure, measurement accuracy, data analysis, remote monitoring, etc.
Key technologies of data security protection system for power grid
Authors: Zhang Yu , Zhao Xichao
Published: November 2020

The extensive application of a large number of intelligent terminals and advanced communication technologies in the smart grid has greatly increased the pathways in which various sensitive business data are destroyed and leaked out. Existing data security protection methods relying mainly on encryption and access control cannot meet the requirements of data security protection in all aspects of the smart grid. Firstly, this paper presents data security protection system management platform architecture for smart grid from the aspects of data classification, data label management, policy management and authority management. On this basis, the data protection system for smart grid introduces the functional modules and flowcharts of the data security protection system for terminals and networks in detail. In the future, the data security protection system can be applied in generation, transmission, substation, power distribution and electricity consumption of power system.
Network completion via deep metric learning
Authors: Wei Qiang
Published: November 2020

Completing networks is often a necessary step when dealing with problems arising from applications in incomplete network data mining. This paper investigates the network completion problem with node attributes. We proposed a new method called DeepMetricNC by exploiting the correlation between node attributes and the underlying network structure. In DeepMetricNC, the correlation is modeled as a nonlinear mapping from node attributes to the probability of edge existence. To obtain the mapping, deep metric learning is applied with batch training and random negative sampling. DeepMetricNC has linear training time complexity and can adapt to large-scale network completion tasks. Experiments of real networks show that DeepMetricNC completes network structures better than other methods, and is more suitable when the portion of the observed part is small.
Research and practice of software protection based on virtual shell technology
Authors: Zhang Long
Published: November 2020

Through software decompilation technology, decompiling software can obtain pseudocode of the program source code, causing more and more events of core technology leakage or threats to software intellectual property rights, especially, the proliferation of pirated software. Aiming at the problem of how to effectively protect the software, this article implements a virtual shell packer with the virtual shell technology based on the QT5 framework as the front-end page frame and the assembly language to write the interpreter. Based on this packer, the code of protected software would be decompiled into logically chaotic code in order to increase the difficulty of cracking. Experiments show that this technology can effectively prevent the original pseudo-code from being restored through decompilation. So the software products are effectively protected.