bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling the Multiband Light Curves of the Afterglows of Three Gamma-Ray Bursts and their Associated Supernovae
Authors: Lian 连 Ji-Shun 纪顺 , Wang 王 Shan-Qin 善钦 , Gan 甘 Wen-Pei 文沛 , Li 李 Jing-Yao 京谣 , Liang 梁 En-Wei 恩维
Published: May 2022

Some dozen supernovae (SNe) associated with long gamma-ray bursts (GRBs) have been confirmed. Most of the previous studies derive the physical properties of the GRB-SNe by fitting the constructed (pseudo-)bolometric light curves. However, many GRB-SNe only have a few filter data, for which the (pseudo-)bolometric light curves are very difficult to construct. Additionally, constructing (pseudo-)bolometric light curves rely on some assumptions. In this paper, we use the multiband broken power-law plus 56Ni model to fit the multiband light curves of the afterglows and the SNe (SN 2001ke, SN 2013dx, and SN 2016jca) associated with three GRBs (GRB 011121, GRB 130702A, and GRB 161219B). We find our model can account for the multiband light curves of the three GRB-SNe (except for the late-time z-band light curve of two events), indicating that the model is a reliable model. The 56Ni masses we derive are higher than those in the literature. This might be due to the fact that the 56Ni masses in the literature are usually obtained by fitting the pseudo-bolometric light curves whose luminosities are usually (significantly) underestimated. We suggest that the multiband model can not only be used to fit the multiband light curves of GRB-SNe that have many filter observations, but also fit those having sparse data.
When Do Stars Go Boom?
Authors: Richer Harvey B. , Cohen Roger E. , Heyl Jeremy , Kalirai Jason , Caiazzo Ilaria , Correnti Matteo , Cummings Jeffrey , Goudfrooij Paul , Hansen Bradley M. S. , Peeples Molly , Sabbi Elena , Tremblay Pier-Emmanuel , Williams Benjamin
Published: May 2022

The maximum mass of a star that can produce a white dwarf (WD) is an important astrophysical quantity. One of the best approaches to establishing this limit is to search for WDs in young star clusters in which only massive stars have had time to evolve and where the mass of the progenitor can be established from the cooling time of the WD together with the age of the cluster. Searches in young Milky Way clusters have not thus far yielded WD members more massive than about 1.1 M
⊙, well below the Chandrasekhar mass of 1.38 M
⊙, nor progenitors with masses in excess of about 6 M
⊙. However, the hunt for potentially massive WDs that escaped their cluster environs is yielding interesting candidates. To expand the cluster sample further, we used HST to survey four young and massive star clusters in the Magellanic Clouds for bright WDs that could have evolved from stars as massive as 10 M
⊙. We located five potential WD candidates in the oldest of the four clusters examined, the first extragalactic single WDs thus far discovered. As these hot WDs are very faint at optical wavelengths, final confirmation will likely have to await spectroscopy with 30 m class telescopes.
On the Energization of Pickup Ions Downstream of the Heliospheric Termination Shock by Comparing 0.52–55 keV Observed Energetic Neutral Atom Spectra to Ones Inferred from Proton Hybrid Simulations
Authors: Gkioulidou Matina , Opher M. , Kornbleuth M. , Dialynas K. , Giacalone J. , Richardson J. D. , Zank G. P. , Fuselier S. A. , Mitchell D. G. , Krimigis S. M. , Roussos E. , Baliukin I.
Published: May 2022

We present an unprecedented comparison of ∼0.52–55 keV energetic neutral atom (ENA) heliosheath measurements, remotely sensed by the Interstellar Boundary Explorer (IBEX) mission and the Ion and Neutral Camera (INCA) on the Cassini mission, with modeled ENAs inferred from interstellar pickup protons that have been accelerated at the termination shock, using hybrid simulations, to assess the pickup ion energetics within the heliosheath. This is the first study to use hybrid simulations that are able to accurately model the acceleration of ions to tens of keV energies, which is essential in order to model ENA fluxes in the heliosheath, covering the full energy range observed by IBEX and CASSINI/INCA. The observed ENA intensities are an average value over the time period from 2009 to the end of 2012, along the Voyager 2 (V2) trajectory. The hybrid simulations upstream of the termination shock, where V2 crossed, are constrained by observations. We report an energy-dependent discrepancy between observed and simulated ENA fluxes, with the observed ENA fluxes being persistently higher than the simulated ones. Our analysis reveals that the termination shock may not accelerate pickup ions to sufficient energies to account for the observed ENA fluxes. We, thus, suggest that the further acceleration of these pickup ions is most likely occurring within the heliosheath, via additional physical processes like turbulence or magnetic reconnection. However, the redistribution of energy inside the heliosheath remains an open question.
Multiwavelength View of the Close-by GRB 190829A Sheds Light on Gamma-Ray Burst Physics
Authors: Salafia Om Sharan , Ravasio Maria Edvige , Yang Jun , An Tao , Orienti Monica , Ghirlanda Giancarlo , Nava Lara , Giroletti Marcello , Mohan Prashanth , Spinelli Riccardo , Zhang Yingkang , Marcote Benito , Cimò Giuseppe , Wu Xuefeng , Li Zhixuan
Published: May 2022

We monitored the position of the close-by (about 370 Mpc) gamma-ray burst GRB 190829A, which originated from a massive star collapse, through very long baseline interferometry (VLBI) observations with the European VLBI Network and the Very Long Baseline Array, carrying out a total of nine observations between 9 and 117 days after the gamma-ray burst at 5 and 15 GHz, with a typical resolution of a few milliarcseconds. From a state-of-the art analysis of these data, we obtained valuable limits on the source size and expansion rate. The limits are in agreement with the size evolution entailed by a detailed modeling of the multiwavelength light curves with a forward-plus-reverse shock model, which agrees with the observations across almost 18 orders of magnitude in frequency (including the HESS data at TeV photon energies) and more than 4 orders of magnitude in time. Thanks to the multiwavelength, high-cadence coverage of the afterglow, inherent degeneracies in the afterglow model are broken to a large extent, allowing us to capture some unique physical insights; we find a low prompt emission efficiency of ≲10−3, a low fraction of relativistic electrons in the forward shock downstream χ

e
< 13% (90% credible level), and a rapid decay of the magnetic field in the reverse shock downstream after the shock crossing. While our model assumes an on-axis jet, our VLBI astrometry is not sufficiently tight as to exclude any off-axis viewing angle, but we can exclude the line of sight to have been more than ∼2° away from the border of the gamma-ray-producing region based on compactness arguments.
Radiative Transfer Modeling of Chang’e-4 Spectroscopic Observations and Interpretation of the South Pole-Aitken Compositional Anomaly
Authors: Chen Jian , Ling Zongcheng , Jolliff Bradley L. , Sun Lingzhi , Qiao Le , Liu Jianzhong , Fu Xiaohui , Zhang Jiang , Li Bo , Liu Changqing , Qi Xiaobin , Lu Xuejin , He Zhiping , Xu Rui
Published: May 2022

Chang’e-4 landed in the Von Kármán basaltic zone affected by Finsen ejecta from the South Pole-Aitken (SPA) “compositional anomaly” (SPACA), providing an opportunity to untangle the origin of the SPACA. We developed a mineral abundance unmixing model and built a spectral library composed of mineral mixtures of plagioclase, low-Ca pyroxene, high-Ca pyroxene, and olivine. Based on the mineral abundances returned by our model, the average plagioclase abundance (60.4 vol.%) of SPACA is beyond the high-plagioclase end of the mineralogical range of SPA impact melt differentiation products and would require an additional contribution from crustal materials. We suggest that either the crust was not entirely removed in the SPA-forming impact or the ejecta from post-SPA basins fed feldspathic materials back onto the SPA basin floor. Our unmixing analyses indicate that the surface regolith of the SPACA is a mixture of 70.2% crustal materials and 29.8% Fe- and incompatible-element-enriched materials.
The genus Pareuryaptus (Carabidae, Pterostichini) in China, with three new country records
Authors: Li Haoyuan , Li Yihang , Shi Hongliang , Liang Hongbin
Published: May 2022

Pareuryaptus is a genus of Carabidae containing 18 species and one subspecies, distributed mainly in the Oriental Region. However, only one species and one subspecies were recorded from China before the present study.

Four species and one subspecies of Pareuryaptus are reported from China with three of them newly recorded: Pareuryaptus adoxus (Tschitschérine) from Yunnan; Pareuryaptus exiguus Dubault, Lassalle & Roux from Guangxi; and Pareuryaptus luangphabangensis Kirschenhofer from Yunnan. Moreover, the male of Pareuryaptus exiguus Dubault, Lassalle & Roux is firstly described and a key to all known Chinese species is provided.
A braconid wasp (Hymenoptera, Braconidae) from the Lower Cretaceous amber of San Just, eastern Iberian Peninsula
Authors: Álvarez-Parra Sergio , Peñalver Enrique , Delclòs Xavier , Engel Michael S.
Published: May 2022

Braconid parasitoid wasps are a widely diversified group today, while their fossil record from the Mesozoic is currently poorly known. Here, we describe Utrillabracon electropteron Álvarez-Parra & Engel, gen. et sp. nov., from the upper Albian (Lower Cretaceous) amber of San Just in the eastern Iberian Peninsula. The holotype specimen is incomplete, although the forewing and hind wing venation are well preserved. The new taxon is assigned to the subfamily †Protorhyssalinae (Braconidae) and, based on characteristics of the wing venation, seems to be closely related to Protorhyssalus goldmani Basibuyuk & Quicke, 1999 and Diorhyssalus allani (Brues, 1937), both from Upper Cretaceous ambers of North America. We discuss the taxonomy of the Cretaceous braconids, considering †Seneciobraconinae as a valid subfamily. We also comment on possible relationships within †Protorhyssalinae, although a phylogenetic analysis is necessary. Additionally, a checklist is included of braconids known from Cretaceous ambers.
Socialisations temporelles pendant l’enfance et inégalités scolaires
Authors: Henri-Panabière Gaële
Published: May 2022

La manière dont nous pensons le temps et agissons en conséquence est une construction sociale. Celle-ci varie selon les conditions matérielles et les modalités de socialisation vécues pendant l’enfance. Or, l’école attend de tous les élèves un rapport au temps unique et normé, fait de ponctualité, constance, rapidité et planification, rapport que favorise surtout le quotidien des familles économiquement et scolairement bien dotées. L’analyse des modalités de socialisations temporelles pendant l’enfance permet ainsi d’approfondir la connaissance des processus de reproduction des inégalités dans lesquels l’école joue un rôle. Ces modalités de socialisation peuvent se décliner en deux types : celles qui relèvent de la familiarisation aux outils de découpage du temps et à un rapport distancié avec les contraintes qu’il représente ; celles qui participent à l’incorporation de règles temporelles par l’expérimentation régulière de rythmes particuliers.
L’épreuve temporelle du chômage
Authors: Demazière Didier , Zune Marc , Amard Pauline , Soleiman François
Published: May 2022

Les études sociologiques sur le chômage se sont très tôt intéressées au rapport au temps des chômeurs, comme une composante importante de leur expérience. Cet entretien revient sur ces questions en abordant le chômage comme une épreuve temporelle : il entraîne une désorganisation par rapport au rythme du travail et confronte les chômeurs à des choix dans leur gestion du temps, selon des ressources et des contraintes inégales. Cette épreuve temporelle est encore renforcée par le contrôle institutionnel de la recherche d’emploi.
Le taux d'intérêt : prix du temps, rançon de la patience
Authors: Daumas Louis , Soleiman François
Published: May 2022

Le taux d’intérêt correspond au prix auquel un agent accepte de prêter de l’argent à un autre au lieu de le dépenser maintenant. C’est ce que cet autre agent paie pour financer une dépense qu’il ne pourrait normalement réaliser que dans le futur. Aussi les taux d’intérêt permettent de réconcilier deux rapports au temps : patience des prêteurs, impatience des emprunteurs. Cet encadré propose un formalisme simple permettant de comprendre comment une variable économique peut être interprétée comme l’expression d’un rapport au temps.
Investir dans le temps
Authors: Massé Bastien
Published: May 2022

Comprendre les pratiques d’investissement en tant que celles-ci se rapportent au futur suppose d’avoir une théorie holiste et dénaturalisante de ces pratiques. Cela permet de faire émerger l’horizon temporel proprement politique de l’investissement.
Temporalité de l’économie : théories des cycles endogènes et croissance
Authors: Glass Audrey , Niedbalec Arnaud
Published: May 2022

Les multiples théories des cycles économiques témoignent du caractère non linéaire de la dynamique économique. Cet encadré présente les principales thèses des cycles endogènes dans leur contexte historique (Juglar, Kitchin et Kondratiev) ainsi que leurs prolongements afin de rendre compte de la manière dont le temps long est appréhendé par les économistes.
La place du « temps » en économie : une source de controverses
Authors: Hallak Julien
Published: May 2022

Cet encadré propose une brève généalogie des débats sur la place du temps et de l’histoire en économie et de ses implications. Il part de la Methodenstreit (querelle des méthodes) au xix e  siècle et de l’institutionnalisme américain au xx e siècle, pour éclaircir des controverses actuelles entretenues par l’école post-keynésienne et la théorie de régulation. Loin d’être un débat abstrait, il touche des questions fondamentales. Peut-on identifier des « lois économiques » stables dans le temps et l’espace ? Comment expliquer les changements de normes et d’habitudes ? Les crises viennent-elles d’événements imprévus ou sont-elles le produit du fonctionnement des marchés eux-mêmes ?
À quoi servent les théories évolutionnistes ? Réflexions et outils pour faire face aux crises contemporaines
Authors: Lazaric Nathalie
Published: May 2022

Nelson et Winter (1982) ont ouvert un nouveau paradigme en matière d’innovation, de survie des firmes, des compétences collectives et des missions de l’État. Cette démarche empirique, analyse, dans un cadre d’imperfection potentielle des organisations et des marchés, les trajectoires technologiques, missions et défis des politiques d’innovation. Les modèles macroéconomiques contemporains permettent de repenser la complexité et les changements structurels et explorent les nouvelles missions de l’État dépassant le simple domaine technologique et organisationnel afin d’éclairer les grands défis du capitalisme : la montée des inégalités sociales, le changement climatique et les incertitudes radicales, dont la crise sanitaire du Covid-19 est une parfaite illustration. C’est la principale richesse de ce paradigme qui part de faits réels stylisés pour mieux comprendre le passé et se projeter dans de multiples futurs qui restent à construire.
Changements économiques et conflits de temporalités
Authors: Hartog François , Kniaz Alix , Régniez Théo
Published: May 2022

Les changements économiques peuvent être à l’origine de conflits de temporalités entre les différents acteurs du monde social. Le recours à la notion de « régime d’historicité » permet dès lors de penser les effets des changements technologiques et environnementaux sur les rapports au temps.
Traces des Satires de Juvénal dans le Franciscanus de George Buchanan
Authors: Catellani Nathalie
Published: May 2022

En composant en 1538 le Franciscanus , George Buchanan est l’un des premiers en France et en Écosse à composer une satire lucilienne à la façon de Juvénal. L’article replace l’œuvre dans son contexte politique et littéraire de création et de diffusion, et s’attache à montrer l’originalité et la créativité d’une satire à la fois morale, politique et religieuse, en analysant la composition du poème, les voix d’énonciation et l’actualisation des modèles antiques majeurs, notamment des Satires de Juvénal.
Un ambassadeur et ses livres au XVI e siècle. La bibliothèque de Bernardin Bochetel
Authors: Fontvieille Damien
Published: May 2022

Après la mort de Bernardin Bochetel, en 1569, un inventaire après-décès est établi à la requête de son frère, Jacques Bochetel. Cet inventaire dévoile une riche bibliothèque d’un peu plus de 400 volumes qui peut être lue à l’aune de la carrière de son possesseur, qui a été avant tout employé dans des missions diplomatiques. Cette lecture permet d’examiner le profil de l’ambassadeur lettré à la Renaissance et la place des connaissances livresques pour les ambassadeurs. Ces connaissances offrent en effet à l’ambassadeur une préparation pour leurs charges diplomatiques mais elles leur servent aussi au quotidien dans l’exercice diplomatique.
L’extraction en France est-elle un extractivisme ? L’exemple des conflits sur les hydrocarbures non conventionnels
Authors: Chailleux Sébastien
Published: May 2022

L’article questionne l’intérêt du cadre d’analyse de l’extractivisme latino-américain pour comprendre les conflits autour des projets d’exploration d’hydrocarbures non conventionnels en France entre 2010 et 2017. En s’appuyant sur une analyse de l’action publique et collective, l’article souligne que le cas français démontre une mise en politique de la thématique des hydrocarbures qui diffère des conclusions traditionnelles de la littérature sur l’extractivisme. L’analyse met en avant que ni les rapports de force, ni la mise en récit, ni les choix politiques ne permettent d’avancer que l’exploration des hydrocarbures en France est un exemple d’extractivisme, défini comme un système asymétrique d’échanges, basé sur une exploitation intensive des ressources naturelles, au profit de compagnies transnationales, soutenues par l’appareil étatique et les partis politiques au pouvoir, contre les communautés locales devant faire face aux pollutions. L’échec des hydrocarbures non conventionnels montre au contraire la capacité d’un mouvement social à prendre possession d’un secteur d’action publique.
Buckwheat – Challenges in nutrition and technology / Ajda – izzivi v tehnologiji in prehrani
Authors: Vombergar Blanka , Tašner Lidija , Horvat Marija , Vorih Stanko , Pem Nataša , Golob Silva , Kovač Tamara
Published: May 2022

The buckwheat market is dominated by common buckwheat, however, the production of Tartary buckwheat is also growing. New varieties of Tartary buckwheat have been registered, and the technology of husking and grinding is being developed. The offer of Tartary buckwheat is becoming more accessible for consumers, and buckwheat products and beverages is strongly increasing in the industry.
The selection of buckwheat dishes in gastronomy is becoming more and more noticeable. Buckwheat festivals, days of buckwheat delicacies, weeks of buckwheat cuisine, and competitions in preparing buckwheat dishes are organized. Traditional and modern media are contributing to the growing popularity of buckwheat. Gluten-free, sugar-free, lactose- free products (including buckwheat) are becoming a food hit. Buckwheat products with less salt are part of the offer of healthy foods.
The present results were presented at the 3th EuroIbra, Prague, Czech Republic in September 2021, and published on the first time in this publication.
 
Izvleček
Na trgu prevladuje navadna ajda, narašča tudi pridelava in uporaba tatarske ajde. Potrjene so nove sorte tatarske ajde, razvija se tehnologija luščenja in mletja ajde. Za potrošnike postaja ponudba tatarske ajde dostopnejša. V industriji se močno razvija ponudba ajdovih izdelkov in pijač. Na trgu je veliko različnih ajdovih kruhov (delež ajde je večinoma do 30 %), tudi ajdov toast in ajdov prepečenec. Prevladuje uporaba navadne ajde, kruhov iz tatarske ajde je malo.
Ponudba ajdovih jedi v gastronomiji je vedno bolj opazna. Organizirajo se festivali ajde, dnevi ajdovih dobrot, tedni ajdove kulinarike, tekmovanja v pripravi ajdovih jedi. K vedno večji popularnosti ajde prispevajo tradicionalni in sodobni mediji. Med svoje vsebine uvrščajo ajdove jedi, ki jim gostinci dajejo pridih kulinaričnih doživetij. Priljubljeni postajajo ajdovi izdelki in jedi brez glutena, brez sladkorja in brez laktoze. Tudi ajdovi izdelki z manj soli so vključeni v ponudbe izdelkov in jedi za ohranjanje zdravja.
Ta članek je bil predstavljen na 3th EuroIbra, Prague, Czech Republic, septembra 2021, tu pa je prvič objavljen.
Christian Zewen (19.03.1959 – 08. 03. 2022)
Authors: Vombergar Blanka
Published: May 2022

Christian Zewen, an outstanding and devoted scientist in buckwheat research, passed away on the 8th of March 2022 in Luxembourg at the age of 62. He was born on (...)
Uso y percepción de las viviendas flexibles de Aranguren y Gallegos en Carabanchel
Authors: Soler Montellano Agatángelo
Published: May 2022

Este artículo recoge el estudio realizado en las viviendas flexibles de Carabanchel (Madrid), de los arquitectos Aranguren y Gallegos. Se trata de una evaluación pos-ocupación del edificio que ofrece información relevante acerca de la experiencia real de los usuarios, de su interacción con la arquitectura flexible del proyecto, y de las fortalezas y debilidades de la flexibilidad en el contexto español. El objetivo último del trabajo es saber si las estrategias flexibles del proyecto ofrecen en la práctica más libertad de uso del espacio doméstico a las familias, y bajo qué condiciones estas estrategias podrían ser replicadas en nuevas promociones de vivienda. La presencia y la edad de los hijos, el nivel educativo de los propietarios, y el sistema de adjudicación de las viviendas se revelan como factores críticos para determinar la actitud (a favor o en contra) de los usuarios con respecto a la flexibilidad.
La Exposición Universal de Bruselas, un cambio de rumbo para la constructora Huarte y Cía
Authors: García-Rosales Gonzalo , Castaño Enrique , Martínez Mónica
Published: May 2022

En 1927 se fundó la constructora Huarte y Cía., una de las más activas y emprendedoras del país durante casi 60 años. A mediados de los años 50 se produjo un cambio generacional en la dirección de la empresa en el momento en que el mundo se preparaba para la Exposición Universal de Bruselas de 1958. Aunque Huarte no consiguió hacerse responsable de la estructura del pabellón español, sí pudo asumir la fabricación del mobiliario diseñado por los arquitectos Corrales y Molezún. La experiencia resultó trascendental para los empresarios pues supuso el primer contacto con varios de los mejores arquitectos y artistas del país, embrión de lo que más tarde sería entendido como el ‘grupo Huarte’, sobre el que ejercerían su intensa labor de mecenazgo. Bruselas fue un punto de inflexión en su desarrollo empresarial, pues consiguió ampliar sus intereses más allá de lo estrictamente constructivo, de tal forma que la promoción de edificios de gran calidad se convirtió en uno de sus objetivos principales.
Designing SiC Based CMUT Structures: An Original Approach and Related Material Issues
Authors: Portail Marc , Chenot Sébastien , Ghorbanzadeh-Bariran Mahdis , Khazaka Rami , Nguyen Luan , Alquier Daniel , Michaud Jean François
Published: May 2022

We present an epitaxy-based approach for designing a 3C-SiC Capacitive Micromachined Ultrasonic Transducer (CMUT). The design requires to consider a 3C-SiC/Si/3C-SiC heterostructure on a Si substrate. This implies to address different growth steps of SiC on Si and Si on SiC. We present some specific growth related issued, namely the control of selectively grown Si on a masked SiC(100) and the further regrowth of 3C-SiC on a Si (110) layer. The final release of the SiC membrane, to define a CMUT, is also addressed using a simple thermal treatment allowing to suppress several technological steps.
High Temperature Etching for Threading Dislocation Investigation on GaN Epi-Layer
Authors: Anzalone Ruggero , Greco Giuseppe , Roccaforte Fabrizio , Fiorenza Patrick , Piluso Nicolo , Severino Andrea
Published: May 2022

In this work, the effect of high temperature molten KOH wet etching on GaN/AlGaN epilayer has been investigated for different family of dislocations. The high etching temperature (up to 510°C) allows a good definition of the pits, making easy the observation and the counts. Such high temperature will allow a detailed study on the statistical distribution of the dislocations on whole wafer by optical microscope for screw/mixed dislocation. A comparison on dislocation density between AlGaN/GaN structure grown on Si (111) substrate and 4H-SiC substrate has been performed.
Toward the Reproducible Growth of Graphene on Wide SiC Steps: A Study of the Geometric Properties of 4H-SiC (0001) Substrates
Authors: Hrich Haitham , Moret Matthieu , Briot Olivier , Paillet Matthieu , Decams Jean Manuel , Landois Périne , Contreras Sylvie
Published: May 2022

Herein, we report an original adaptation of an XRD set-up in order to measure the miscut angle values in our 4H-SiC on axis substrates with a high precision of ± 0.02°. This study also reveals a correlation between the formation of wide steps on 4H-SiC(0001) and the relative orientation of the SiC crystalline planes versus the gas flow direction. These two results paves the way towards the reproducible growth of graphene over wide SiC steps.
Via Size-Dependent Properties of TiAl Ohmic Contacts on 4H-SiC
Authors: May Alexander , Rommel Mathias , Beuer Susanne , Erlbacher Tobias
Published: May 2022

P-type Ti/Al-based contact vias of different sizes but identical processing were electrically characterized using linear transfer length method (TLM) patterns and metal-oxide-semiconductor (MOS) transistors. While the TLM patterns and MOS transistors with large vias follow ohmic contact behavior, Schottky contact properties were observed for smaller contact via dimensions. Focused ion beam (FIB) analysis of the contact vias verified the presence of Ti3SiC2 on large 66 μm x 25 μm contact vias and its absence on smaller 16 μm x 3 μm ones, correlating its absence with the electrical Schottky properties.
Advances in 200 mm 4H SiC Wafer Development and Production
Authors: Manning Ian , Moeggenborg Kevin , Soukhojak Andrey , Searson Jon , Gave Matthew , Chung Gil , Sanchez Edward
Published: May 2022

200 mm diameter n-type 4H SiC wafers were produced from bulk crystals grown using a physical vapor transport (PVT) method. The configuration of the growth cell was modified to both allow for the growth of larger crystals with respect to the standard 150 mm process, and to induce a thermal environment necessary to increase the mass deposition rate. A 25% increase in deposition rate was achieved relative to the standard process. The resulting wafers exhibited resistivity uniformity comparable to commercial 150 mm product. Optical and x-ray techniques were used to evaluate wafer quality, and revealed surface and bulk crystal defect densities acceptable for epilayer growth.
Analysis of Pulsed Laser Spot Effects on NiTi Wires
Authors: Vâlsan Dragoș Dumitru , Bolocan Vlad Marius , Novac Andrei , Chilnicean Gheorghe Amadeus , Crăciunescu Corneliu Marius
Published: May 2022

The welding of shape-memory alloys is a challenge due to the fact that there are numerous compositions and because the properties are greatly influenced by the temperature. Of the multitude of shape-memory alloy systems, the most popular and widely used is the Ni-Ti system. Pulsed laser welding is a solution used for joining NiTi shape-memory alloys, having the advantage of localized heating and the possibility to adjust the welding parameters to obtain optimal properties. NiTi wires were welded using a 500W pulsed laser equipment by varying the current intensity. Thus, laser melted spots were made on a NiTi wire, changing only the value of current intensity in 20A increments in the range of 100-200A. The results analyzed by scanning electron microscopy showed, as expected, that as the current intensity increased, the spot size and the heat affected zone (HAZ) increased for each spot. Differential scanning calorimetry revealed that the martensitic transformation is still present in all samples, but with a decrease in peaks related to the phase transformation, as well as an increase of the temperature (8-12 °C), compared to the base material.
Valorization of Abrasive Waterjet Garnet Wastes by Innovative Integration in Building Materials
Authors: Baeră Cornelia , Szilagyi Henriette , Gruin Aurelian , Bolborea Bogdan , Perianu Ion Aurel
Published: May 2022

The current study focusses on possibilities of valorizing the spent Garnets produced by waterjet cutting operations, by integrating it in construction materials, as raw material substitution. The waterjet material processing by the use of abrasive Garnets is also in continuous expansion, due to its versatility and quality performance, this also generating large quantities of waste: the initial waterjet sludge collected in recipients during the process of material processes, dries and gradually turns into waste dumps, usually randomly deserted, especially in countries lacking specific legislation ad applicability methods. Therefore, converting the spent Garnets into filler replacement into concrete mixes could represent a huge benefit for both industries: constructions, lacking fillers, as sand replacement in concrete mix, possibly improving the material durability as well, and also material processing industry, by solving the waste generation problem. The initial, preliminary results, favorable to the use of spent Garnets in concrete and mortars, are confirmed by supplementary, international research, determining local interest for such valorization of the Garnet waste. This paper presents the latest research achievements in this topic and also, the derived possibilities regarding multidisciplinary studies which could determine the applicability of the waste in the construction industry, in Romania.
Fabrication and Characterization of Epitaxial Graphene Field Effect Transistor Devices Based on a Monolithic Bottom Gate
Authors: Aslanidou Sofia , García-García Alberto , Rius Gemma , Godignon Philippe
Published: May 2022

Current electronics technology increasingly demands higher integration, flexibility, higher efficiency, and performance aspects such as compatibility with higher temperature operation of the semiconductor devices, which may find limitations when silicon is used. The superior intrinsic properties of SiC, eventually combined with the ability of growing monolithically epitaxial, high quality graphene on a SiC wafer (1), makes it a reliable alternative for some electronic applications, such as field effect transistors (FET), radio frequency (RF) power amplifiers, integrated circuits (IC), or sensors. In this work, we describe the fabrication and preliminary electrical characterizations of epitaxial graphene (EG) on a SiC substrate FET devices based on an alternative back gate architecture. We propose a new approach in which the FET device is built on a 4◦ off-axis cut, N+ doped 4H-SiC substrate (the back gate) with, on top of, it a 1μm semi-insulating homoepitaxial layer of SiC compensated with vanadium (the dielectric layer). EG will be used as FET conduction channel. Using this V-compensated dielectric layer is aimed to minimize effects on the FET characteristics such as from defects in the SiC crystal, especially below the FET active areas, which would have occurred when using ion implantation to create a buried gate. The EG film was grown by the high temperature Si sublimation method under an Ar ambient. Raman spectroscopy, Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) were applied in the structural characterization of epigraphene. The lack of D-peak in Raman spectra, together with SEM and AFM images, indicate that high quality monolayer to few layer epitaxial graphene fully covering the SiC surface is deposited. The electrical characteristics of the EG channel-devices and the functionality of the bottom gate were examined with 2-probe and 4-probe method. The electrical properties of the FET devices were also investigated with 3 terminal configuration.
Impact of N Doping on 3C-SiC Defects
Authors: Calabretta Cristiano , Scuderi Viviana , Cannizzaro Annalisa , Anzalone Ruggero , Mauceri Marco , Crippa Danilo , Boninelli Simona , La Via Francesco
Published: May 2022

This work studies the variation of the defects density of in situ doped 3C-SiC layers during heteroepitaxial Chemical Vapour Deposition (CVD). A review on the evolution of defects density as a function of 3C-SiC grown thickness, for different N doping concentrations is offered. The doping range spanned in the experiment suits the realization of power devices.The outcome of this work provides an explanatory picture of the significant drop in stacking faults density by roughly an order of magnitude through the N doping at concentrations of the order of ~2.9×1019 cm-3 during the growth. Conversely, N doping shows to favor the development of dislocation-like defects within the crystalline matrix. However, in few um, the crystal is able to display an effective dislocation closure mechanism, which rapidly recovers crystal quality.
Impact of Dislocation on Warpage of Thinned 4H-SiC Wafers
Authors: Cafra Brunella , Anzalone Ruggero , Severino Andrea
Published: May 2022

In this work the relationship between changes in wafer center bow after thinning process and the wafer morphology has been shown. KOH wet etching allowed the observation and counting of dislocation in 4H-SiC substrate. In deep a correspondence between changes in wafer center bow and the dislocation density of the SiC substrate has been observed. By using a counting software, a relationship with the basal plane dislocation and center bow has also been observed.
Enhanced Resonant Raman Scattering of GaN Functional Layers Using Al Thin Films - A Versatile Tool for Multilayer Structure Analysis
Authors: Muravitskaya Alina , Rumyantseva Anna , Ndohi Atse Julien Eric , Sonneville Camille , Planson Dominique , Adam Pierre Michel , Potiron Sylvain , Lazar Mihai
Published: May 2022

In order to selectively analyze active thin layers close to surface in power devices structures, Raman scattering is necessary with UV excitation. However, the Raman spectra of GaN are usually affected by the direct bandgap photoluminescence of the material, which interferes with the Raman measurements and decreases the quality and resolution of the Raman spectra. In this work, we demonstrate experimentally that nanostructured aluminum films deposed on GaN epitaxial layers decrease the influence of the photoluminescence on the resonant Raman spectra and increase its overall spatial resolution under UV illumination.
Transmission Electron Microscopy Study of Single Shockley Stacking Faults in 4H-SiC Expanded from Basal Plane Dislocation Segments Accompanied by Threading Edge Dislocations on both Ends
Authors: Nishio Johji , Ota Chiharu , Iijima Ryosuke
Published: May 2022

Double-rhombic shaped single Shockley stacking faults (1SSFs) were considered to have a converted threading edge dislocation (TED) on the shallower side of the initial basal plane dislocation segments. However, the structural analysis using transmission electron microscopy (TEM) revealed other possible configuration of the double-rhombic 1SSFs expanded from basal plane dislocations (BPDs) of which both ends were connected with two TEDs.
Comparison of the H3TRB Performance of Silicon and Silicon Carbide Power Modules
Authors: Hoffmann Felix , Schmitt Stefan , Kaminski Nando
Published: May 2022

In this work, the H3TRB performance of power modules with SiC MOSFET chips is investigated and compared to their silicon counterparts with similar electrical ratings. For this purpose, SiC MOSFETs and silicon IGBT chips are packaged in the same housing and with the same packaging technology and an H3TRB test is performed on both types of test devices. The results show that while both types exhibit an excellent H3TRB performance, the SiC MOSFETs had a significantly longer time to failure but also a wider failure distribution. Hence, the investigations presented in this paper confirm that properly designed SiC devices feature an equal or even better ruggedness against electro-chemical stress than standard silicon devics and are equally suitable for applications, which require operation in harsh environments.
Demonstration of 2kV SiC Deep-Implanted Super-Junction PiN Diodes
Authors: Ghandi Reza , Hitchcock Collin , Kennerly Stacey
Published: May 2022

We report successful demonstration of 2kV, SiC super-junction (SJ) PiN diodes formed by deep implantation of Al and N. In our devices, alternating 12μm deep n-type and p-type SJ pillars fabricated on a 10μm pitch and result in a SJ diode with a measured blocking voltage 500V higher than comparable non-SJ diodes. Four activation anneals ranging from 1700 °C to 2000 °C were compared for effectiveness in eliminating post-implant lattice damage, and the optimum anneal condition was identified.
Reserves for Improving the Quality of Metal Layers of the 450Kh30M and 500Kh22B7 Types by Regulation of Silicon Content in Hard-Facing Consumables
Authors: Peremitko Valerii , Nosov Denys , Yevdokymov A. , Golyakevich Andrey A.
Published: May 2022

An effective way to improve quality of metal layers of the 450Kh30M and 500Kh22B7 types by controlling the silicon content in hard-facing consumables is shown. The influence of silicon and aluminum content in hard-facing consumables on content of silicon, aluminum, chromium and carbon in the hard-faced layer as well as the amount of non-metallic inclusions of silicate type was studied to develop mathematical models and to derive corresponding dependencies. As a result some corrections to the composition of the hard-facing consumables were proposed to improve quality of metal layers of high-alloyed white cast irons of the investigated types.
Thermal and Mechanical Properties of Mortar Incorporated with Phase Change Materials (PCMs)
Authors: Heniegal Ashraf Mohamed , Ibrahim Omar Mohamed Omar , Frahat Nour Bassim , Amin Mohamed
Published: May 2022

Phase change materials (PCMs) integration into cement mortar is among the new studies of interest regarding modern energy-saving techniques and developing the thermal properties in buildings. This study aims to integrate microencapsulated-PCMs (micro-PCMs) with cement mortar at 0, 5, 10, and 15% to replace natural sand for thermal properties improvement of the building envelope. In addition, the effect of using micro-PCMs on mechanical, thermal properties, and PCMs leakage problems were studied. The cement mortars incorporated with micro-PCMs were investigated by scanning electron microscopy (SEM), thermal conductivity, and mechanical properties as (compressive, flexural, and tensile). The results indicate a decreasing trend of thermal conductivity values with the increase in PCMs content in the cementitious system with the percentages of 11, 21, and 30% for 5, 10, and 15% PCMs, respectively. Similarly, mechanical properties results also confirmed that integrating incorporating mortars with PCMs resulted in the reduction in the compressive strength by 22, 31, and 46%, respectively. Therefore, using the PCMs with cement mortar can build envelope applications to store thermal energy, provide the indoor temperature at a comfortable range, and reduce the consumption energy in buildings.
Structural, Electronic and Optical Properties of 6H-SiC and 3C-SiC with the Application in Solar Cell Devices
Authors: Taibi Ibrahim , Abid Hamza
Published: May 2022

6H-SiC and 3C-SiC structural, electronic and optical properties have been calculated by applying the principles of density functional theory based on the plane wave pseudo-potential. This method is implanted in Wien2k Software. Structural parameters are calculated at the level of Perdew Burke and Ernzerhof (PBE) parameterized generalized gradient approximation (GGA). The obtained results given in Table I were compared to the experimental data in relation with the lattice constant hexagonal ration c/a and the band gap value parameters of 6H-SiC and 3C-SiC, there was a very accurate concordance. The superior gap value and the good absorption coefficient drives us to realize a p+nn+ solar cell device using SILVACO Software. The 3C-SiC material resulted in a considerable performance for photovoltaic applications.
A New Approach in the Field of Hydrogen Gas Sensing Using MEMS Based 3C-SiC Microcantilevers
Authors: Shanmugam Priyadarshini , Iglesias Luis , Portail Marc , Dufour Isabelle , Certon Dominique , Alquier Daniel , Michaud Jean François
Published: May 2022

This paper demonstrates the ability of 3CSiC microcantilevers (μCs) to monitor binary gas mixture without sensitive coating. Here, 3CSiC is chosen in particular, as the newly designed sensor will be placed in a radioactive environment. The change in gas concentration is identified using relative shifts in the cantilever’s mechanical resonance frequency (∆fr). The presented microcantilevers work on electromagnetic actuation and inductive detection. In this paper, the fabrication process, optical characterization results using laser Doppler vibrometry and test results under a gas mixture environment are demonstrated. The presented limit of detection shows the ability of 3CSiCμCs to detect less than 1% of hydrogen in nitrogen, which makes them suitable for the targeted application.
Experimental Study of the Effect of Partial Replacement of Cement with Glass Powder on Concrete Properties
Authors: Elmikass Ahmed G. , Makhlouf Mohamed H. , Mostafa Tarek Sayed , Hamdy Gehan A.
Published: May 2022

This experimental research aims at investigating the possibility of utilizing local glass waste in the production of concrete for construction. Experimental program is conducted to study the effects of using glass powder (GP) obtained by crushing of local glass waste as partial replacement of cement on the fresh and hardened properties of concrete. Five percentages of GP were used: 0%, 10%, 15%, 20%, and 25% by weight of cement. For all concrete mixes, slump test was made for fresh concrete and tests were made for hardened concrete to evaluate compressive strength, splitting tensile strength and flexural strength. The experimental results show that workability increased by increasing GP content. Concrete compressive strength was reduced for all mixes with glass powder, but is improved by time. The positive effect of using GP as cement replacement extends to 20% on concrete tensile strength. The results showed that as the amount of GP increases the flexure strength. The use of 20 % glass powder as cement replacement decreased concrete compressive strength by 3.2% at 56 days, achieved better tensile strength at 28 days, increase flexure strength by 18.6% at 28 days and showed good performance compared to all other mixes.
Microscopic Evaluation of Al2O3/p-Type Diamond (111) Interfaces Using Scanning Nonlinear Dielectric Microscopy
Authors: Ogata Yu , Yamasue Kohei , Zhang Xufang , Matsumoto Tsubasa , Tokuda Norio , Cho Yasuo
Published: May 2022

Improvement of channel mobility is required to improve the performance of the inversion channel MOSFETs using diamond. The previous studies have suggested that high interface defect density (Dit) at the Al2O3/diamond (111) interface has a significant impact on the carrier transport property on a channel region. To investigate the physical origins of the high Dit, especially from microscopic point of view, here we investigate Al2O3/p-type diamond (111) interfaces using scanning nonlinear dielectric microscopy (SNDM). We find the high spatial fluctuations of Al2O3/hydroxyl (OH)-terminated diamond (111) interface properties and their difference by the flatness of the diamond surface.
Green Synthesis of Fe3O4/TiO2 Nanoparticles Using Extracts of Moringa oleifera: Microstructural and Optical Properties
Authors: Tumbelaka Rivaldo Marsel , Istiqomah Nurul Imani , Mabarroh Ni’matil , Suharyadi Edi
Published: May 2022

Fe3O4 and Fe3O4/TiO2 magnetic nanoparticles have been successfully prepared using an eco-friendly green synthesis method with various Moringa Oleifera (MO) extract concentrations. The X-ray diffraction and transmission electron microscopy results confirmed that the microstructure of Fe3O4 nanoparticles is a cubic inverse spinel structure with an average particle size of 9.2–11.7 nm and lattice parameters is in the range of 8.14–13.60 Å and the MO did not change the morphological structure of Fe3O4. Fourier-transform infrared showed that the samples had magnetic particles vibration peaks at 632 cm-1 and 570 cm-1, 500–700 cm-1 for Ti-O peaks, and 1047 cm-1 for aromatic C-C indicating green synthesis. Furthermore, the results of UV-VIS data presented the absorption edges of Fe3O4, Fe3O4-MO, and Fe3O4/TiO2-MO were 187.9 nm, 198.7 nm, and 197.1 nm, respectively. The bandgap energy of Fe3O4-MO is in the range of 2.62–2.66 eV and the bandgap energy of Fe3O4/TiO2-MO is 2.76 eV which explains that it depends on the bioactive compounds. Based on these results, the green synthesis nanoparticles have the potential to be applied in the industrial sector, especially for photocatalyst applications.
Impact of Surface Emissivity on Crystal Growth and Epitaxial Deposition
Authors: Fan Wei , Lennartz Jeff , Schmidt-Sane Peter , Kozak Brian , Balland Bruno , Galyukov Alex , Zimina Daria , Feezell Daniel
Published: May 2022

Tantalum carbide (TaC) coating, produced in an ultrahigh temperature chemical vapor deposition (CVD) process, exhibited high thermal and chemical stabilities, low emissivity, and high purity. Low emissivity of 0.3~0.43 was measured on TaC coating at 1000°C and compared with the one of SiC coating. As revealed in both simulation and experiment, the low emissivity of TaC coatings not only improves temperature uniformity in the SiC PVT process, but also reduces power consumption in both SiC crystal growth and GaN epitaxial deposition. The results provide important guidance to process tuning when switching from a conventional graphite or SiC-coated component to its TaC-coated counterpart.
Effect of N and Al Doping on 3C-SiC Stacking Faults
Authors: Calabretta Cristiano , Scuderi Viviana , Anzalone Ruggero , Cannizzaro Annalisa , Mauceri Marco , Crippa Danilo , Boninelli Simona , La Via Francesco
Published: May 2022

This study offers a comprehensive examination of the behavior of 3C-SiC crystals grown on 4° off-axis (100) Si substrates with different off-axis angles along <110> and <100> for N and Al doping, respectively. The investigation takes advantage of molten KOH etching to conduct an in-depth investigation of the average density and size of the SFs inside the crystal for both n- and p-type doped 3C-SiC epitaxial layers. Moreover, 3C-SiC grown on a <100> off-cut substrate was revealed to have a greater concentration of SFs due to the absence of self-annihilation along the plane (-1-10). Considering two different doping ranges suitable for IGBTs and MOSFETs development, the impact of doping and off-angle on the crystal quality, concentration, and length distribution of SFs was then investigated in order to quantify the influence of N and Al incorporation on the structural and optical characteristics of the semiconductor. It turned out that under heavy nitrogen doping (~1019 cm-3), when the dopant concentration grew, the average length of the stacking faults (SFs) expanded while their density dropped.