bluuebunny/crossref_metadata_2025 huggingface dataset:
Political and Scientific Persecutions – the Case of Hayrie Memova-Suleymanova
Authors: Muratova Nurie , Zafer Zeynep
Published: November 2020

The research is focussed on the scientific carrier and life destiny of Hayriye Süleymanoğlu Yenisoy, lecturer of Turkish language at Sofia University, interpreted in the wider frame of the policies of the communist regime to Turks in Bulgaria. We followed how the political events in the second half of the 20th century in communist Bulgaria played a decisive role for the professional carriers of Turkish scientists and lecturers in the country. Their destinies were not exceptions on the background of the persecutions of ideologically unhandy persons by the regime. Our research is related to the entirety of scientific life in the totalitarian Bulgaria, but is focussed on the mechanisms of repressions of Turkish intelligentsia in the context of the policy of the communist power to Turks and other Muslims in Bulgaria. The paper considers the means of destruction of the educated Turkish elite after 1944 and the efforts of the communist regime to create politically loyal new elite among the Turks. But the short flirt of the communist power with the Muslim minorities finished up with the persecution of the elite of the Turkish community who suffered mostly of the increasing assimilation efforts. The regime did away with many representatives of this elite requiring impossible loyalty from them – refusal of their ethnic identity, changing their Muslim names, falsification of scientific facts. The Bulgarian – Turkish thematic dictionary created by Hayriye Memova was convicted of being espionage order from Turkey. She was dismissed from the academic institutions and compelled to survive by working as cleaner in a factory for 4 years. Against her an investigation was initiated by the State Security which lasted for 7 years and included 19 secret agents most of them her colleagues, students and random acquaintances. Nevertheless she defended her PhD and habilitated in Bulgaria, in Turkey where she emigrated in 1989 with thousands of Turks who were expelled from the country, her scientific degrees were not acknowledged and she had to habilitate again in Baku. Following the scientific and personal trajectory of Hayriye Memova who is a representative example of the resistance we followed the policies of the regime to scientific community focussing on the control of the repressive apparat of the regime over the Sofia University.
About the two-volume trilingual dictionary of linguistic terms
Authors: Krejčí Pavel
Published: November 2020

The author reviews the book Nadezhda Stalyanova and Elena Kreychova. Rechnik na lingvistichnite termini za studenti slavisti A–N (balgarski ezik – cheshki ezik – polski ezik). Sofia: Paradigma 2019, 142 p., ISBN 978-954-326-387-5; Rechnik na lingvistichnite termini za studenti slavisti O–Ya (balgarski ezik – cheshki ezik – polski ezik). Sofia: Paradigma 2020, 118 p., ISBN 978-954-326-425-4 .
Post-communist Interpretation of History in the Albanian Literature in Kosovo
Authors: Tahiri Lindita , Hamiti Muhamet
Published: November 2020

This article focuses on stylistic choices in the novel Im atë donte Adolfin (My father loved Adolph) by the Albanian author in Kosovo Mehmet Kraja (2005) as a strategy to generate a post-communist perspective of interpreting history. By blending first-person narration as confidentiality and third-person narration as conventionality (Barthes, 1978), the possessive construction ‘my father’ in this literary text serves both as referential label and deictic, generating dual focalization (Phelan, 2005). The heterodiegetic narrator is positioned simultaneously as a neutral eye witnessing narrator and as a signal of subjectivity. Even in cases of intradiegetic role the narrator remains detached interweaving his voice with the voice of the character. The synchronized overt and distant narratorial stances in this novel correspond with the demonstration of historical discourse as both subjective and factual narration. The relationship between fiction and truth has been widely treated in the post-modern intellectual thought, and as Borg (2010) points out in his study on Beckett and Joyce, the radical narrative innovations are “examples of a peculiarly modernist engagement with the nature of factual and fictional truth” (p. 179), suggesting that in modern literary texts “every event exists factually and fictionally at the same time” (p. 187). As a resonance to Borg’s analysis of modernist literature, in Kraja’s novel the knowledge about history consists of both factual and imaginative elements, bringing “the moment of truth in all its potential” (p. 191).
Engagement laboral en colaboradores de establecimientos de consumo gastronómico de Tarma
Authors: Paredes Pérez Marco Antonio , Villavicencio Arias Víctor Jorge , Palomino Crispín Antonio Eleodoro
Published: November 2020

Objetivo Determinar el nivel de engagement laboral en trabajadores de pollerías de Tarma, Métodos: la investigación fue de tipo básica, nivel descriptivo y diseño descriptivo transversal y simple, los métodos específicos fueron observacional, inductivo y deductivo; la técnica fue la encuesta y el instrumento fue la Escala Uwes de engagement laboral; los resultados se procesaron sobre una escala de 1 a 4, donde 1 fue igual a nunca, 2 casi nunca, 3 casi siempre, y 4 siempre; luego se establecieron rangos en función al método de máximo y mínimos de baremos, recodificándose la variable en tres niveles de valoración e interpretación alto medio y bajo, el muestreo fue intencional no probabilístico, las unidades de estudio fueron 10 pollerías de Tarma y se encuesto a 80 colaboradores de tales organizaciones, Resultados: El nivel de engagement en colaborares de establecimientos de consumo gastronómico de Tarma es medio, al igual que las dimensiones de vigor, dedicación y absorción. Conclusión: los colaboradores se encuentran relativamente satisfechos con su trabajo actual, hasta encontrar una mejor oportunidad, puesto que consideran que este tipo de labores son temporales en relación a sus proyectos de vida
INTRACEREBROVENTRICULAR DELIVERY OF ADENO-ASSOCIATED VIRUSES INTO NEONATAL MOUSE BRAIN FOR GENE THERAPY PRECLINICAL STUDIES FOR GNAO1 ENCEPHALOPATHY
Authors: Vassilieva S. , Shmidt A. , Starikova A. , Bardina M.
Published: November 2020

In the present work we validated neonatal intracerebroventricular injections for AAV-mediated transgene delivery into GNAO1-rich regions of the murine brain. This administration route can be used for testing efficacy of AAV- based gene therapy for GNAO1 encephalopathy in the mouse models.
BUCHANS: A MINING TOWN: EXCAVATING ECONOMIC
EXPLOITATION THROUGH CANADIAN DOCU-DRAMATURGY
Authors: Vahia Aditi , Nanavati Devang
Published: November 2020

The figures that 1% of the richest possessing 44% of the world’s wealth in 2020
(“Facts: Global Inequality”) evidently indicates the immediacy of addressing the
horrific economic gaps which have been irreversibly disrupting the socioenvironmental balances across the globe and within the national borders. This
paper aims to have a broader view of the glocal implications of this scenario with
the help of a Canadian documentary experiment, which can be seen as microcosm
of the macrorealities.
It may be noted that the Canadian confederation was completed when
Newfoundland (in the milieu of which the action of Buchans takes place) joined it
at last in 1949- which almost coincides with the constitutional re-formation of India.
Like the industrially developing India, the economically developed Canada also
aspires to follow democratic ideals and all-inclusive policies which can guarantee
the protection of the basic rights, needs and dignity of all human beings,
irrespective of their socio-economic status.
It would be interesting to see in this paper as to how Buchnas, a Canadian
documentary experiment, brings to light the plights of the labor class working in the
darkest corners of the mines, and how the exploitative operations of a giant mining
company shown in this play stands for the predatory gaze of all the profit-intensive
operations that continue to exploit a huge part of humanity as well as the collective
natural sources.
FROM ONCE READ TO TWICE PERFORMED: EXPLORING THE QUESTIONS OF ERFORMATIVITY AND RASA IN MODERN INDIAN DRAMA
Authors: Surve Anshu
Published: November 2020

Recognising, analysing, and theorising the convergence and collapse of clearly
demarcated realities, hierarchies, and categories is at the heart of postmodernism:
this premise is at the core of this article when mediating two distinctive theories of
criticism. The paper is drawn on the dualitatem of the critical theories of
Performativity and Rasa with the objective of initiating deliberations and debates on
Indian Aesthetics. Performance studies as an interdisciplinary discourse uses
performance as a lens to engage with social, political, religious questions. The Rasa
Theory in Indian dramaturgy and aesthetics have been critically analysed and
applied on quite a few western and Indian literary works but seldom has a literary
work been critically studied through the dual critical lenses of performativity in
relation to the Rasa experience. Rasa is a manifestation of emotions translated to
the audience in the form of shared experience. The proposed research is a humble
attempt to engage with the questions: How performance of a drama and its affective
experience can be attributed to the Rasa experience? This interdisciplinary research
is contextualised in modern drama where in the complex matrix of performance, its
affect becomes a shared Rasa experience that resonates in the form of a narrative
with binaries of universality and subjectivity.
INDOMITABLE SISTERHOOD IN KAVITA KANE’S SITA’S SISTER: AN
ARCHETYPE OF WOMEN CAMARADERIE
Authors: Raviya Hitesh , Malviya Parul
Published: November 2020

Universally bringing its philosophical implications that has been nurturing our minds, the
Ramayana has had a huge impact on us and it still does. Often reckoning it for
establishing prototypes of brotherhood and male companionship, the epic is laden with
many such examples and the eminent amongst them is Ram and his three brothers. But
imperceptibly we sense the similar relevance given to sisterhood and women
companionship. Kavita Kane, a mythological-fiction writer is known for retelling the
stories from the two Indian epics, the Ramayana and the Mahabharata. In her novel
Sita’s Sister, we stumble upon impregnable sisterhood. The novel is a narration of the
Ramayana from perspective of Urmila, in which women-bonding is far and wide visible.
From childhood to teenage, and to their adulthood, the four sisters in solidarity lead us
on a road that ends in women camaraderie. We encounter many instances in the novel
where women stand, speak and support other women. So as we learn principles and
ethics from the set models of brotherhood, we can also grasp several virtues from the
woman characters. Taking into consideration, how the relationship grows between them
as they pass through different stages of their lives, the research paper will analyze how
the writer has made their bond competent enough to be set on the pedestal of ideal
sisterhood.
A STUDY OF NON-PERFORMING ASSETS WITH SELECTED
SCHEDULED COMMERCIAL BANKS
Authors: Dodia Bhavsinh
Published: November 2020

The banking sector reforms measures since 1991, had epoch-making/ likely to
have a significant effect on a particular period of time changes for banking activities
with international standard. Earlier, profits were seldom a matter of serious concern to
banks. Deposit mobilization was the main goal. These by gone days profit became a
driving force through cutting of operational cost. The earning capacity and profitability
in many banks is affected by NPA, which affects the liquidity, profitability and equity. In
recent time the reduction of NPAs in banks is biggest challenges in the Indian
economy. An attempt of present study that knows RBI guidelines regarding NPA
recognition, classification and provisioning and an effort to made evaluate the
operational performance of selected 10 Public Sector Banks and 10 Private Sector
Banks with using various statistical tool& techniques like Mean, Standard deviation
and ANOVA test used to analyzed data.
Heat Transfer Model in a Rotary Drum During the Fermentation Process
Authors: Mohd Jamil Norazaliza , Nafsun Aainaa Izyan , Mohd Kasim Abdul Rahman
Published: November 2020

A new mathematical model describing heat transfer during the fermentation process in a rotary drum is proposed. The model includes representations of the kinetic reactions, the temperature of the solid bed, and physical structures within the rotary drum. The model is developed using five ordinary differential equations and was then solved using the Runge-Kutta method embedded in MATLAB software. A reasonable behaviour for the temperature profile to the fermentation process is achieved. The results show that the mass of the solid bed, contact heat transfer coefficient, and the wall temperature has a significant effect on the fermentation process in a rotary drum.
Experimental Analysis of The Effect of Hydrophobic Coating on Pressure Drop in Small Pipes
Authors: Knights Michael J , Donald Roy , Galletta Diego , Kul Pun , Hamad Faik A
Published: November 2020

In this paper, experimental results are reported to quantify the effect of hydrophobic coating LT-8 on frictional drag of water flow in pipes of 450 mm length. Five pipes of 1, 2, 3, 4, and 5 mm inner diameter were tested. The results from 1, 2 and 3 mm diameter pipes demonstrated an average frictional drag reduction of 9%, 11.5% and 3%, respectively, while the results from 4mm and 5mm pipes showed an increase in frictional drag of 12% and 10%, respectively. The 2mm and 4mm pipes were also tested with a half application of hydrophobic coating. The half coated 2mm pipe showed decrease in drag while 4mm pipe showed increase in drag. The results indicate a relationship between drag reduction/ increase within the percentage of coated surface. The main conclusions are, the flow changed from laminar state to the liquid-air wetting surface condition (Cassie-Baxter wetting state) at the pipe surface and then destabilized by the turbulent boundary layer and entered the liquid wetting surface (Wenzel wetting state) will be appeared. This transition lead to a reduction in friction drag for laminar flow condition and increase in drag for turbulent flow condition.
Az emberölés elhatárolása a halált és az életveszélyt okozó testi sértéstől
Authors: Benedek Zoltán
Published: November 2020

The author provides an overview of how homicide can be differentiated from bodily harm leading to death.
Kézírás technikai eszközzel történő rekonstrukciós vizsgálata, avagy a precíz betörő esete
Authors: Sajgó Ildikó
Published: November 2020

The author provides an overview of an investigation where the perpetrator was identified through writing analysis.
The Population III Origin of GW190521
Authors: Liu Boyuan , Bromm Volker
Published: November 2020

We explore the possibility that the recently detected black hole binary (BHB) merger event GW190521 originates from the first generation of massive, metal-free, so-called Population III (Pop III) stars. Based on improved binary statistics derived from N-body simulations of Pop III star clusters, we calculate the merger rate densities of Pop III BHBs similar to GW190521, in two evolution channels: classical binary stellar evolution and dynamical hardening in high-redshift nuclear star clusters. Both channels can explain the observed rate density. However, the latter is favored by better agreement with observation and less restrictions on uncertain parameters. Our analysis also indicates that given the distinct features of the two channels, future observation of BHB mergers similar to GW190521 with third-generation gravitational wave detectors will greatly improve our knowledge of the evolution of Pop III BHBs, especially for their dynamics during cosmic structure formation.
Description of a new species of Aleuroclava Singh, 1931 (Hemiptera, Aleyrodidae) infesting Schima superba from China
Authors: Wang Ji-Rui , Xu Zhi-Hong , Zhou Guo-Xin
Published: November 2020

A new whitefly species, Aleuroclava schimae Wang, sp. nov. infesting leaves of Schima superba (Parietales, Theaceae) is described and illustrated from Zhejiang, China. Puparia of the new species are elliptical, broad at the transverse molting suture region and broadly truncate posteriorly. Thoracic and caudal tracheal pores are discernible. In life, the puparia are covered by a thin layer of white wax.
A new species from subtropical Brazil and evidence of multiple pelvic fin losses in catfishes of the genus Cambeva (Siluriformes, Trichomycteridae)
Authors: Costa Wilson J. E. M. , Feltrin Caio R. M. , Katz Axel M.
Published: November 2020

A third pelvic-less species of Cambeva from river basins draining the Geral mountain range in southern Brazil is described. It is distinguished from other congeners lacking pelvic fin and girdle, C. pascuali and C. tropeiro, by having six pectoral-fin rays, 20–23 dorsal procurrent caudal-fin rays, 15–20 opercular and 25–30 interopercular odontodes and a different colour pattern consisting of flank dark brownish-grey with two irregular horizontal rows of small pale yellow grey marks. Whereas available molecular evidence indicates that C. pascuali is more closely related to C. zonata, a species with well-developed pelvic fin, and C. tropeiro is more closely related to C. balios, another species also with well-developed pelvic fin; osteological data strongly suggest that the new species herein described is more closely related to C. diatropoporos than to other congeners. Therefore, this study indicates that the pelvic fin and pelvic-fin support have been lost independently in each of these three species of Cambeva, which corresponds to 11% of all describe species. This result highly contrasts with the closely-related trichomycterine genera Trichomycterus, in which only one in 50 species lost pelvic fin and girdle (0.2%) and Scleronema with all the nine included species having well-developed pelvic fin. These data suggest a stronger tendency to losing pelvic fin in Cambeva, but factors favouring this evolutionary event are still unknown.
Pilas galvánicas flexibles de Ag-Al a base de textiles
Authors:   Centro de Nanociencias y Micro y Nanotecnologías, Instituto Politécnico Nacional, Hernández-Como Norberto , Aleman-Arce Miguel ,   Centro de Nanociencias y Micro y Nanotecnologías, Instituto Politécnico Nacional, Hernández-Cuevas Francisco Javier ,   Centro de Nanociencias y Micro y Nanotecnologías, Instituto Politécnico Nacional, Elizalde-Sandoval Ricardo David ,   Escuela Superior de Ingeniería Textil, Instituto Politécnico Nacional
Published: November 2020

Los textiles inteligentes brindan diversas funcionalidades como son: acabados especiales sobre las telas (antibacteriales, antimanchas, ignifugo, hidrofóbico, etc.), sensado de diversas variables (físicas, químicas, biológicas, etc.), circuitos electrónicos de propósito especifico (calefacción, antenas, almacenamiento y procesamiento de información, etc.), pantallas e iluminación, todo esto incorporado en la ropa y calzado. Las aplicaciones electrónicas normalmente se deben poder retirar de las telas antes de un ciclo de lavado para evitar un rápido deterioro. Actualmente, todo este tipo de aplicaciones utilizan fuentes de energía externas, baterías comerciales o conexión a la línea eléctrica para satisfacer sus necesidades de consumo de potencia. Por esta razón, para brindar la independencia de fuentes externas es más conveniente que los textiles inteligentes utilicen pilas o baterías igualmente integradas en los mismos textiles. En este trabajo se estudia la pila galvánica a base de electrodos de plata y aluminio utilizando telas de algodón. Se reporta su curva de descarga y se extrae la capacidad de la pila en unidades de miliampere por hora (mAh). Adicionalmente, las pilas textiles fabricadas contienen las siguientes características: son ligeras, son de área pequeña, son flexibles, su proceso de fabricación es simple y sus características eléctricas son escalables.
Crecimiento de películas delgadas en atmósfera de oxígeno mediante la técnica de sublimación-CSVT
Authors:   Instituto Politécnico Nacional, ESFM. UPALM, Zacatenco, CDMX, Salomón Preciado Ana María , Aleman-Arce Miguel ,   Instituto Politécnico Nacional, CNMN. UPALM, de Moure Flores Francisco Javier ,   Universidad Autónoma de Querétaro, Aguilar Hernández Jorge Ricardo ,   Instituto Politécnico Nacional, ESFM. UPALM, Zacatenco, CDMX, Vigil Galán Osvaldo ,   Instituto Politécnico Nacional, ESFM. UPALM, Zacatenco, CDMX, Contreras Puente Gerardo Silverio ,   Instituto Politécnico Nacional, ESFM. UPALM, Zacatenco, CDMX
Published: November 2020

Las celdas solares de CdTe/CdS en película delgada depositadas sobre substratos flexibles y en la configuración sustrato no han tenido buena respuesta fotovoltaica, dando menores eficiencias que sus homologas desarrolladas en configuración superestrato. Son dos los procesos relacionados con el deterioro de las propiedades de la película absorbente CdTe, estos son: 1) el tratamiento con cloruro de cadmio que se deposita sobre el CdTe antes del CdS no permite que se mejore la unión entre estos semiconductores; 2) el contenido de cobre que se deposita en el contacto trasero de la celda o durante el depósito de CdTe degradando las propiedades de la película. Sin embargo, en el año 2013 se logró desarrollar una celda solar CdTe/CdS sobre sustrato de molibdeno flexible, incorporando de manera controlada capas atómicas de cobre entre el CdTe y el CdS, alcanzando una eficiencia de 11.5 %. Estos resultados dejan claro que aún hay mucho por investigar en cuanto a los materiales disponibles para celdas solares y la importancia que tiene el conocer sus propiedades para entender y dirigir la investigación hacia desarrollo de dispositivos fotovoltaicos eficientes, de bajo costo y que brinden beneficio a largo plazo. En el presente trabajo se presentan los resultados de estudios de las películas delgadas de CdTe depositadas mediante la técnica de sublimación por transporte de vapor en espacio cercano (CSVT, por sus siglas en inglés), sobre sustratos de molibdeno flexible. En estos depósitos se variaron espesores para evaluar la interacción del oxígeno usado durante el depósito en las propiedades estructurales, ópticas, eléctricas, químicas y morfológicas del CdTe. Los resultados mostraron que el oxígeno forma óxidos de teluro y teluratos de cadmio en la superficie de la película de CdTe. Además, se encontró evidencia de defectos comunes del CdTe tales como maclas y fallas de apilamiento.
Aplicación de la técnica machine learning al desarrollo de catalizadores para procesos de producción de energía
Authors:   Instituto Politécnico Nacional, Laboratorio de Fotocatálisis, CICATA, Rodriguez Christian , Bokhimi Xim ,   Instituto de Física, Universidad Nacional Autónoma de México, Mantilla Angeles ,   Instituto Politécnico Nacional, Laboratorio de Fotocatálisis, CICATA
Published: November 2020

En la actualidad, el desarrollo de catalizadores es de vital importancia en diversas áreas, siendo muy importante su aplicación en procesos de generación de energía. Al ser las propiedades buscadas para logar una alta eficiencia catalítica en estos materiales cada vez más específicas, el desarrollo experimental de éstos es una tarea muy complicada. Mediante el uso de técnicas de Inteligencia Artificial (IA) como Machine Learning (ML) se plantea la posibilidad de simplificación de estas actividades integrando, a un bajo costo computacional, algoritmos que permitan predecir, con un alto grado de certidumbre, las propiedades de un material diseñado y sintetizado de manera experimental en un laboratorio, reduciendo tiempo y costos en el desarrollo de los mismos.
Nanopartículas de oro y sus efectos sobre microorganismos acuáticos, un estudio sobre "Daphnia Pulex"
Authors:   Instituto Politécnico Nacional, Unidad Profesional Interdisciplinaria de Biotecnología, Departamento de Ciencias Básicas, Abrica-González Paulina , Balderas-López José Abraham ,   Instituto Politécnico Nacional, Unidad Profesional Interdisciplinaria de Biotecnología, Departamento de Ciencias Básicas, Zumelzu-Delgado Ernesto ,   Universidad Austral de Chile, Facultad de Ciencias de la Ingeniería, Instituto de Materiales y Procesos Termomecánicos, Nimptsch-Maass Jorge ,   Universidad Austral de Chile, Facultad de Ciencias, Instituto de Ciencias Marinas y Limnológicas
Published: November 2020

En las últimas décadas, la nanotecnología ha emergido como un área de investigación que está encontrando aplicaciones en múltiples campos. El mercado actual incluye nanomateriales que proporcionan grandes ventajas sobre los materiales en su forma convencional, una de éstas, su mayor área de contacto, lo que los hace ideales como sustancias catalíticas, mejorando este tipo de procesos con la consecuente reducción de insumos. Dentro de los nanomateriales comúnmente utilizados, las nanopartículas de oro se han aplicado principalmente en biomedicina, salud y belleza, sector automotriz y electrónica. Sin embargo, el uso cada vez más generalizado de nanopartículas no va aparejado con estudios sobre el impacto ambiental que conlleva la disposición final de sus residuos, especialmente en medios acuáticos, destino habitual de muchas sustancias utilizadas en procesos industriales, los cuales han sido poco estudiados. La presente investigación aborda el efecto que tienen las nanopartículas de oro con recubrimiento de quitosano sobre Daphnia pulex, microorganismos generadores primarios en la cadena trófica. Como resultado fundamental de este trabajo se estableció una dosis letal media (EC50) de 0.5721 mg/L de Au en este tipo de microorganismos, este estudio confirma así la importancia de llevar a cabo más investigación sobre la toxicidad de nanopartículas funcionalizadas, especialmente de oro, en organismos acuáticos microscópicos que son la base de muchas cadenas tróficas en ríos y lagos.
Aspects of Extremely Low Frequency Electric and Magnetic Cleanliness on Space Platforms
Authors: Mavropoulou Alexandra P. , Bechrakis Triantafyllos Alexandros D. , Nikolopoulos Christos D.
Published: November 2020

Nowadays, a wide range of space missions accommodate ever-stricter electromagnetic cleanliness requirements arising either from the need for more precise measurements or from the implementation of highly sensitive equipment. Therefore, the establishment of a methodology that ensures the minimization of the electric and/or magnetic field in specific areas inside or outside the spacecraft structure is crucial. Towards this goal, the current chapter proposes that utilizing the results of a process completed during the early design stages of a mission, that is, the measurement and characterization of each implemented device, the desired elimination of the field can be achieved. In particular, the emerged electromagnetic signatures of the units are proven essential for the proposed methodology, which, using a heuristic approach, defines the optimal ordinance of the equipment that leads to system-level electromagnetic field minimization in the volume of interest. The dimensions of the devices and the effect of the conductive surfaces of the spacecraft's hull are also taken into account.
Laser Printing of Chiral Silicon Nanoprotrusions by Asymmetric Donut-Shaped Femtosecond Pulses
Authors: Syubaev Sergey A. , Porfirev Aleksey P. , Kuchmizhak Aleksandr A.
Published: November 2020

Here, we showed formation of chiral nanoprotrusions upon direct laser ablation of bulk crystalline silicon (c-Si) wafer with single femtosecond (fs) pulses having asymmetric donut-shaped intensity profile. Breaking circular symmetry of the irradiating donut-shaped fs-pulse beam was demonstrated to switch the geometry of formed surface nanoprotrusions from regular to chiral, while the chirality of the obtained Si nanostructures was found to promote with a degree of asymmetry of the laser beam. The obtained experimental results explain, for the first time, the formation of previously reported chiral c-Si nanostructures produced via donut-shaped beam ablation in terms of uneven helical flow of laser-melted Si material caused by asymmetry of initial intensity and temperature pattern on laser-irradiated Si surface. Our findings open a pathway towards easy-to-implement inexpensive fabrication of chiral all-dielectric nanostructures for advanced nanophotonic applications.
Au Nanoparticle-Decorated TiO2 Nanospheres Produced by Laser Reshaping in Water
Authors: Gurbatov Stanislav O. , Kulinich Sergei A. , Kuchmizhak Aleksandr A.
Published: November 2020

Here, we demonstrate formation of spherical-shaped amorphous titania (TiO2) nanoparticles decorated with Au nanoclusters via nanosecond pulse ablation (7-ns, 532-nm wavelength) of commercially available TiO2 nanopowders dispersed in an aqueous solution of chloroauric acid (HAuCl4). Generation of such hybrid nanostructures was found to be caused by laser-induced remelting of the initial TiO2 nanoparticles, stimulated by Au nanoclusters that can adsorbed on their surface and boost light-to-heat conversion process in optically transparent titania. The morphology and chemical composition of the obtained hybrid nanomaterials were studied in detail via scanning electron microscopy, Raman spectroscopy and Energy Dispersive X-ray spectroscopy. The average size and number of Au nanoclusters reduced on the TiO2 nanoparticle surface was shown to be tuned by varying the initial nanoparticles/HAuCl4 concentration ratio. Spectroscopic measurements of single hybrid nanoparticles scattering, as well as the corresponding numerical calculations of electromagnetic fields structure near their surface indicate synthesized functional nanomaterials as extremely promising for numerous applications of modern optics, optoelectronics and nanophotonics, e.g., realization of advanced chemo-and biosensing platforms, as well as of new-generation solar cells.
Visualization of Optical Uniformity Alloyed Single Crystals of Lithium Niobate
Authors: Pikoul Olga Y. , Sidorov Nikolay V. , Teplyakova Natalya A. , Palatnikov Mikhail N.
Published: November 2020

It was shown that laser conoscopy can visually detect even slight changes in the optical characteristics of a crystal when it is doped. It has been found that the defective structure of LiNbO3:Zn (4.5 mol. %), LiNbO3:Mg (3.0–5.5 mol.%) crystals associated with an uneven entry of an impurity leads to a local change in the elastic characteristics of the crystal and the appearance of mechanical stresses that distort the conoscopic patterns. This can be an abnormal optical biaxiality, which manifests itself in the form of a rupture and enlightenment of the "Maltese cross" in the center of the conoscopic crystal pattern, or local birefringent inclusions that are recorded as additional interference patterns against the background of the main conoscopic pattern, both in the center of the field of view and in its peripheral area.
Structural Heterogeneity of an Amorpous Nanocrystalline Alloy in the Nanometer Range
Authors: Frolov Anatoly M. , Dolzhikov S.V. , Belokon Valery I.
Published: November 2020

An approach to describe the structure of amorphous alloys obtained by fast quenching from a melt, based on the fluctuation theory of phase transitions, is proposed in t in such objects.
Defects and Morphology Contribution to Photoluminescence of CH3NH3PbI3 Nanostructured by Femtosecond Laser Pulses
Authors: Tonkaev Pavel , Zhizhchenko Aleksey Y. , Gets Dmitry S. , Larin Artem , Zuev Dmitry , Zakharenko Alexander M. , Kuchmizhak Aleksandr A. , Makarov Sergey M.
Published: November 2020

Despite basic optoelectronic properties of metal-organic perovskites are quite robust to defects, thelatter affect performance of related photovoltaic devices made of such promising materials. Recently,direct femtosecond projection lithography appeared as prospective tool for high-performing nondestructivenano- and microstructuring of perovskite films. Here, we study in details how defects affectthe photoluminescence properties of CH3NH3PbI3 hybrid perovskite films patterned with single- andmulti-pulse irradiation with flat-top femtosecond laser pulses. Scanning electron, wide-field multiphoton,photoluminescence and laser confocal microscopies being combined with photoluminescencedecay measurements are carried out for these studies. The obtained experimental results are analyzedwith a model for carriers kinetics allowed to determine contributions from radiative and non-radiative processes.
Effect of Solvent Annealing on Optical Properties of Perovskite Dualfunctional Devices
Authors: Verkhogliadov Grigorii A. , Masharin Mikhail A. , Gets Dmitry S. , Danilovskiy Eduard Yu. , Makarov Sergey M. , Zakhidov Anvar A.
Published: November 2020

Mixed-halide perovskite allows to realize conception of light-emitting solar cell (LESC) due to possibility to in-situ change device band structure by formation of dipole layer under applied voltage and intrinsic properties of perovskite ions. LESC has optimized perovskite-based solar cell (SC) architecture, but light-emitting diode (LED) regime performances is still low. Defect passivation can improve LED efficiencies due to reducing nonradiative recombination via defect levels. Solvent annealing allows to regulate film formation process and leads to better morphology and grain size for our application. Defect density is significantly reduced due to this passivation method. Here we demonstrate effect of annealing in vapors of dimethylformamide (DMF), dimethyl sulfoxide (DMSO) and acetonitrile (MeCN) atmosphere on LESC photovoltaic characteristic, electroluminescence (EL) peak wavelength and photoluminescence quantum yield (PLQY) of mixed-halide perovskite film.
Pulsed Laser Ablation of Silicon Nanowires in Water and Ethanol
Authors: Zabotnov Stanislav V. , Skobelkina Anastasiia V. , Kashaev Fedor V. , Kolchin Aleksandr V. , Popov Vladimir V. , Presnov Denis E. , Sergeeva Ekaterina A. , Kirillin Mikhail Yu. , Golovan Leonid A.
Published: November 2020

A novel two-stage technique to fabricate silicon nanoparticles is reported. At the first stage, silicon nanowire arrays are formed by metal-assisted chemical etching. At the second stage, the nanoparticles are produced by pulsed laser ablation of the silicon nanowire targets in water and ethanol. The fabricated particles have relatively small mean size in the range of 24 – 45 nm depending on the used buffer liquid. The ablation threshold of the silicon nanowire arrays is 2 – 11 times smaller than that for crystalline silicon targets. Owing to the achieved parameters, the proposed technique is more efficient in comparison with traditional approaches of mechanical milling of silicon nanowires and laser ablation of crystalline silicon. Raman spectroscopy study revealed crystalline structure of the fabricated silicon nanoparticles. The properties of the produced nanoparticles indicate their high potential in biophotonics.
Photonic Nanojet Generation in Transmission and Reflection Mode
Authors: Sergeev Alexander A. , Sergeeva Ksenia A. , Nepomniaschiy Aleksandr Vladimirovich , Voznesenskiy Sergey S.
Published: November 2020

This paper is related to the problem of enhancing the optical and functional performance of luminescent gas sensors via its excitation by photonic nanojets. The novel sensor structure consisting of the array of alumina microparticles covered by optical sensitive layer was designed. The parameters of the photonic nanojets generated in both transmission and reflection modes has been numerically end experimentally studied. It was shown that PNJ in reflection mode demonstrates an unexpectedly high enhancement of photoluminescence. It was obtained that the excitation of the sensitive layer by photonic nanojets extends the limit of gaseous ammonia detection up to 0.1 ppm for reflection mode and up to 0.02 ppm for transmission mode.
Concentration Phase Transition in a Two-Dimensional Ferromagnet
Authors: Chepak Alexander Konstantinovich , Afremov Leonid Lazarevich , Mironenko Alexander Yuryevich
Published: November 2020

The concentration phase transition (CPT) in a two-dimensional ferromagnet was simulated by the Monte Carlo method. The description of the CPT was carried out using various order parameters (OP): magnetic, cluster, and percolation. For comparison with the problem of the geometric (percolation) phase transition, the thermal effect on the spin state was excluded, and thus, CPT was reduced to percolation transition. For each OP, the values ​​of the critical concentration and critical indices of the CPT are calculated.
Size Effect on Optical Properties of Silicon Dioxide Hollow Particles
Authors: Iurina Viktoriia , Neshchimenko Vitaly V. , Li Chun Dong
Published: November 2020

The optical properties of silicon dioxide hollow particles with different size were investigated in UV/visible/near-IR region, as well as X-ray photoelectron spectra were analyzed. Synthesis of SiO2 hollow particles was carried out using a template method. It was established that hollow particle reflectance lower than bulk microparticles. Absorptance in the red and near infrared spectral ranges increases with decreasing size of hollow particles, but in the UV-region conversely. This is due to different absorption centers.
Increased Antibacterial Activity by Photoactivation of Composites Based on ZnO Nanoparticles
Authors: Goncharova Darya A. , Kulinich Sergei A. , Nemoykina Anna L. , Svetlichnyi Valery A.
Published: November 2020

Antibacterial composites based on linen and NPs obtained by pulsed laser ablation of a zinc target in air were synthesized at various concentrations of the active component (ZnO NPs). The surface morphology and optical properties of ZnO/linen composites were investigated by scanning electron microscopy and UV-visible spectroscopy. The antibacterial activity of ZnO/linen composites was tested on S.aureus in accordance with ISO 20743:2013. It was found that the antibacterial activity depends on the concentration of ZnO NPs. High antibacterial activity of the composites was achieved when the concentration of the active component was of 0.25 mg/cm2. At a concentration of 0.1 mg/cm2 the composites showed only a bacteriostatic effect. The use of photoactivation of composites by LED radiation of 365 nm for 10 min led to an increase in antibacterial activity about 1.5 times for the samples in both concentrations.
Investigation of the Mechanism of Electric Conductivity of Strontium Bismuthate Sr6Bi2O11
Authors: Shtarev Dmitry Sergeevich , Shtareva Anna Vladimirovna , Syuy Alexander Vjacheslavovich , Likhtin Vladimir Valentinovich
Published: November 2020

The paper presents data on the temperature dependence of the conductivity of strontium bismuthate Sr6Bi2O11. It is shown that the temperature dependence of conductivity cannot be described in the framework of existing models. It was found that at a temperature of about 400 K a change in the radius of localization of the charge carrier is observed.
Morphology and Chemical Composition of Organic Coatings Formed Atop PEO-Layers
Authors: Egorkin Vladimir S. , Kharchenko Ulyana V. , Izotov Nikolay V. , Vyaliy Igor E. , Gnedenkov Andrey S. , Tolkanov Dmitry K. , Runov Andrey K. , Minaev Alexander N. , Sinebryukhov Sergey L. , Gnedenkov Sergey V.
Published: November 2020

The plasma electrolytic oxidation (PEO) process was used to form an oxide layer on an Al5754 aluminum alloy for subsequent application of organic coating. The effect of the oxidation time on the morphology and anticorrosion properties of PEO-coatings was investigated. The oxide layer possess low apparent porosity and provides high adhesion to the paint. The resulting composite coating (CC) is characterized by high barrier properties in chloride solution.
Nanocomposite of Tin and Lead Oxides Prepared in Plasma of Pulsed High-Voltage Discharge Process: Synthesis and Electrochemical Characteristics
Authors: Gnedenkov Sergey V. , Kuryavyi Valery G. , Opra Denis P. , Sinebryukhov Sergey L. , Sokolov Alexander A. , Neumoin Anton I. , Sergienko Valentin I.
Published: November 2020

In the present paper, a composite containing mixed oxides of tin and lead has been synthesized by the method of pulsed high-voltage discharge. Material was characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis and transmission electron microscopy. The composite consists of SnO2 and PbO particles with an average size of ~350 nm, and SnPb2O4 nanowhiskers with size of 100 nm in diameter and few microns in length. The electrochemical performance of nanocomposite as a potential anode of lithium-ion battery has been investigated by the cyclic voltammetry and galvanostatic charge/discharge test in the potential range of 3.0–0.005 V. The reversible capacity of 821 mA·h/g was realized after 5-fold cycling at a current density of 100 mA/g. It was established that further cycling of the material is accompanied by a dramatic capacity fade: only 13 % of the initial capacity was obtained already after 10 cycles. The observed degradation in performance of nanocomposite results from its inability to compensate large lithiation/delithiation-induced volume expansion.
Methods for Controlling the Surface Architecture of Coatings Formed by Plasma Electrolytic Oxidation
Authors: Rudnev Vladimir S. , Kilin Kirell N. , Lukiyanchuk Irina V. , Vasilyeva Marina S.
Published: November 2020

The paper considers approaches that can lead to the growth of micro-and nanocrystals on the surface of coatings formed on valve metals by plasma electrolytic oxidation (PEO). Among these approaches, there are the use of electrolytes-suspensions, the addition of organic compounds to the electrolytes, the thermal annealing of ‘PEO layer/metal’ composites, including impregnated ones.
Computer Simulation of Oxygen Vacancy Formation in YFeO3 Perovskite
Authors: Gnidenko Anton A. , Chigrin P.G. , Kirichenko Evgeny A.
Published: November 2020

The pseudopotential method and density functional theory with Hubbard correction were used to study changes in the atomic and electronic structure of yttrium orthoferrite (YFeO3) during vacancy formation. Depending on the value of non-stoichiometry in YFeO3−δ(δ = 0.0625 and 0.25), the energy gain of one of the two types of vacancy decreases from 0.3 to 0.1 eV. So it have been shown that high concentrations of oxygen vacancies make more insignificant the difference in the type of formed vacancies.
Multilayer Heterostructures with Embedded CrSi2 and β-FeSi2 Nanocrystals on Si(111) Substrate: From the Formation to Photoelectric Properties
Authors: Galkin Nikolay G. , Galkin Konstantin Nickolaevich , Subbotin Evgeniy Y. , Chusovotin Evgeniy Anatoljevich , Goroshko Dmitrii L.
Published: November 2020

The studies are devoted to the development of the technology of multilayer incorporation of nanocrystals (NCs) of semiconductor chromium and iron disilicides with a layer density no less than 2x1010 cm-2, the establishment of the growth mechanism of heterostructures with two types of NCs, the determination of their crystalline quality and optical properties, as well as the creation and study of rectification and photoelectric properties of p-i-n diodes based on them. Morphologically smooth heterostructures with 6 embedded layers of CrSi2 nanocrystals and two types of embedded nanocrystals (with 4 layers of CrSi2 NCs and 2 layers of β-FeSi2 NCs) for optical studies and built-in silicon p-i-n diodes were grown for the first time. The possibility of optical identification of interband transitions in embedded nanocrystals in the photon energy range of 1.2 - 2.5 eV was determined from the reflection spectra and the strongest peaks in reflection from the integrated nanocrystals were determined: 2.0 eV for CrSi2 NCs and 1.75 eV for β-FeSi2 NCs. The created p-i-n diodes have a contact potential difference of 0.95 V, regardless of the type of embedded NCs. At 80 K, an absorption band (0.7 - 1.1 eV) was detected in the diodes, which was associated with carrier photo generation in the embedded CrSi2 and β-FeSi2 NCs. From the spectra of the photoresponse at 80 K, the band gap widths in the NCs were determined: 0.50 eV in CrSi2 and 0.70 eV in the superposition of the CrSi2 and β-FeSi2 NCs.
Photocatalytic Reduction of CO2 over Metal/BaTiO3 Catalysts
Authors: Dubkov Sergey , Savitskiy Andrey , Ryazanov Roman , Shatila Viktor , Trifonov Alexey Yu. , Shkal Alexey , Kitsyuk Evgeny , Shtyka Oleksandr , Ciesielski Radoslaw , Gromov Dmitry
Published: November 2020

The paper presents the results of experimental studies of a photoactive catalyst in the form of barium titanate fibers with deposited particles of nickel, platinum and gold. Barium titanate fibers were synthesized by the molten salt method. The obtained barium titanate fibers were studied by SEM, TEM, XRD, and Raman spectroscopy. Photocatalytic studies showed that barium titanate fibers with platinum nanoparticles are the most active of the three prepared Metal/BaTiO3 samples.
Formation of Fe2Si Wetting Coating on Si(001) 2×1 and Growth of a Stable Fe Nanolayer: AES and EELS Study
Authors: Plusnin Nikolay I. , Maslov Andrey M. , Il’yashenko Vladimir M.
Published: November 2020

The structural-phase state of two-dimensional (d = 1 - 3 ML) coatings before and after annealing and that of Fe nanolayers (d = 4 - 10 ML) were investigated on Si (001)2×1 by electron spectroscopy methods of Auger-electrons and energy losses. The room (30 °С) and lowed (≤ 1250 °С) temperatures of the Si (001) substrate and Fe vapor, respectively, were used during Fe deposition. This study showed the following. An ordered two-dimensional 1×1 phase of Fe stable up to 600 °C and then a Fe2Si wetting coating stable at 250 °C form near the thickness 1 ML and 3 ML, respectively. Fe deposition on this Fe2Si coating leads to the one-after-another formation of the Fe3Si, the Si-in-Fe solution, and then a stable up to 250 °C Fe nanofilm with segregated Si.
Screening of a Panel of Low Molecular Weight Compounds That Inhibit Synovial Fibroblast Invasion in Rheumatoid Arthritis
Authors: Sugiura Tomoko , Kamino Hiroki , Nariai Yuko , Murakawa Yohko , Kondo Masahiro , Kawakami Makoto , Ikeda Noboru , Uchio Yuji , Urano Takeshi
Published: November 2020

Increased invasion of synovial fibroblasts and their involvement in cartilage damage are characteristic phenotypes of rheumatoid arthritis (RA). To identify low molecular weight compounds that suppress synovial fibroblast invasion, a panel of inhibitors (n = 330) was initially screened using a real-time cell analysis system for human synovial fibroblasts that were enzymatically isolated from surgical samples of RA patients. To evaluate the effects of the inhibitors identified in the screen, synovial fibroblast migration was measured using a wound-healing assay, and phosphorylation of intracellular signaling molecules was determined by immunoblots. Several candidate inhibitors were identified in the screen, including inhibitors against platelet-derived growth factor receptor (PDGFR), Akt, PI3K, and glycogen kinase synthetase 3 (GSK-3). These inhibitors strongly suppressed synovial fibroblast migration after 72 h and downregulated phosphorylation of Akt (Ser473) at 48 h. When the inhibitors were removed from the culture conditions, both migration and phosphorylated Akt (Ser473) levels were restored. Furthermore, all the categories of inhibitors except for PDGFR inhibitor IV decreased cell proliferation as well as IL-6 production in synovial fibroblasts. Interestingly, GSK-3 inhibitors increased anti-inflammatory cytokine IL-10 production but suppressed IL-23 production from LPS-primed macrophages obtained from healthy donors. In conclusion, blocking PDGFR, PI3K, or GSK-3 could have therapeutic value as an RA treatment that targets the invasion/migration of synovial fibroblasts.