scholarly journals Международная школа-семинар Экситоны в кристаллах и полупроводниковых наноструктурах", посвященная 120-летию со дня рождения Е. Ф. Гросса, Санкт-Петербург 10-12 октября 2017 года Экситонная спектроскопия полупроводников методом генерации оптических гармоник [1mm] (О б з о р)

2018 ◽  
Vol 60 (8) ◽  
pp. 1463
Author(s):  
Д.Р. Яковлев ◽  
В.В. Павлов ◽  
А.В. Родина ◽  
Р.В. Писарев ◽  
J. Mund ◽  
...  
Keyword(s):  
Spin Structure ◽  
Stark Effect ◽  
New Information ◽  
Bulk Semiconductors ◽  
Electric And Magnetic Fields ◽  
Low Dimensional ◽  
Linear Optical Spectroscopy ◽  
Experimental And Theoretical Studies ◽  
Harmonics Generation

AbstractNonlinear optical phenomena are widely used for the study of semiconductor materials. The paper presents an overview of experimental and theoretical studies of excitons by the method of optical second and third harmonics generation in various bulk semiconductors (GaAs, CdTe, ZnSe, ZnO, Cu_2O, (Cd,Mn)Te, EuTe, EuSe), and low-dimensional heterostructures ZnSe/BeTe. Particular attention is paid to the role of external electric and magnetic fields that modify the exciton states and induce new mechanisms of optical harmonics generation. Microscopic mechanisms of harmonics generation based on the Stark effect, the spin and orbital Zeeman effects, and on the magneto-Stark effect specific for excitons moving in an external magnetic field are considered. This approach makes it possible to study the properties of excitons and to obtain new information on their energy and spin structure that is not available when the excitons are investigated by linear optical spectroscopy. As a result of these studies, a large amount of information was obtained, which allows us to conclude on the establishing of a new field of research—exciton spectroscopy by the method of optical harmonics generation.

BOOK PUBLISHING IN UKRAINE: THE FACTORS OF EVELOP

2016 ◽  
Author(s):  
Victor Shpak
Keyword(s):  
Information Society ◽  
Publishing Industry ◽  
Book Industry ◽  
Book Publishing ◽  
Advanced Technology ◽  
Information Space ◽  
New Information ◽  
Information And Communication ◽  
National Information

This article is devoted to analysis of the modern problems of book publishing in the context of national information space. Development of the Ukrainian state is impossible without development of national book publishing, which is a part of its information space. In Ukraine, as one of the post-Soviet states, the formation of new information and communication system is based on its own information tradition, mentality and features of spiritual culture of the Ukrainians. It plays an important role in shaping culture, spirituality, comprehensive vision and consciousness of the nation. They were and they are a source of knowledge and the most effective way of its transfer. The transience of processes occurring the era of information society, radical socio-economic reforms, sectoral technological revolution requires the continuous scientific researches and analysis, identifying the trends in publishing industry as one of the most important factors in the state’s democratic progress. The author summarizes the development of book publishing of Ukraine and shows its role and place in the modern information society. The study of the modern book publishing is impossible without digression into the past, without finding out the roots of studying of the analysis object. The specific problems of the book industry are identified. It is concluded that in the modern Ukraine the publishing business has intensified, although the positive changes are taking place very slowly: the appropriate economic conditions for development of the publishing industry have not been created, the equipment are outdated; editorial, publishing and printing equipment of domestic manufacture are nonavailable; introduction of advanced technology are low; purchasing ability of the population is low; the sales network of printed products has been destroyed and so on. The businesses are becoming increasingly uneconomical. We propose some measures to improve this situation, strengthening the role of industry in the national information space. The key to improve the situation may be systematic and persistent efforts of the Ukrainian government to support the industry.The reason is that a comprehensive study requires from the performers not only historical knowledge, but also economic, managerial, psychological, political efforts and so on. The most important thing that the society and the state should need is the component of doctrine of information security in the context of the national security

scholarly journals Anomalous transport due to Weyl fermions in the chiral antiferromagnets Mn3X, X = Sn, Ge

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Taishi Chen ◽  
Takahiro Tomita ◽  
Susumu Minami ◽  
Mingxuan Fu ◽  
Takashi Koretsune ◽  
...  
Keyword(s):  
Technological Innovation ◽  
Essential Role ◽  
Condensed Matter ◽  
Zero Field ◽  
Theoretical Studies ◽  
Planar Hall Effect ◽  
Topological States ◽  
Experimental And Theoretical Studies ◽  
Weyl Fermions

AbstractThe recent discoveries of strikingly large zero-field Hall and Nernst effects in antiferromagnets Mn3X (X = Sn, Ge) have brought the study of magnetic topological states to the forefront of condensed matter research and technological innovation. These effects are considered fingerprints of Weyl nodes residing near the Fermi energy, promoting Mn3X (X = Sn, Ge) as a fascinating platform to explore the elusive magnetic Weyl fermions. In this review, we provide recent updates on the insights drawn from experimental and theoretical studies of Mn3X (X = Sn, Ge) by combining previous reports with our new, comprehensive set of transport measurements of high-quality Mn3Sn and Mn3Ge single crystals. In particular, we report magnetotransport signatures specific to chiral anomalies in Mn3Ge and planar Hall effect in Mn3Sn, which have not yet been found in earlier studies. The results summarized here indicate the essential role of magnetic Weyl fermions in producing the large transverse responses in the absence of magnetization.

scholarly journals Contribution of the CK2 Catalytic Isoforms α and α’ to the Glycolytic Phenotype of Tumor Cells

Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 181
Author(s):  
Francesca Zonta ◽  
Christian Borgo ◽  
Camila Paz Quezada Meza ◽  
Ionica Masgras ◽  
Andrea Rasola ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Protein Kinase ◽  
Cancer Cells ◽  
Tumor Cells ◽  
Therapeutic Strategies ◽  
The Other ◽  
Osteosarcoma Cell ◽  
Monomeric Form ◽  
New Information

CK2 is a Ser/Thr protein kinase overexpressed in many cancers. It is usually present in cells as a tetrameric enzyme, composed of two catalytic (α or α’) and two regulatory (β) subunits, but it is active also in its monomeric form, and the specific role of the different isoforms is largely unknown. CK2 phosphorylates several substrates related to the uncontrolled proliferation, motility, and survival of cancer cells. As a consequence, tumor cells are addicted to CK2, relying on its activity more than healthy cells for their life, and exploiting it for developing multiple oncological hallmarks. However, little is known about CK2 contribution to the metabolic rewiring of cancer cells. With this study we aimed at shedding some light on it, especially focusing on the CK2 role in the glycolytic onco-phenotype. By analyzing neuroblastoma and osteosarcoma cell lines depleted of either one (α) or the other (α’) CK2 catalytic subunit, we also aimed at disclosing possible pro-tumor functions which are specific of a CK2 isoform. Our results suggest that both CK2 α and α’ contribute to cell proliferation, survival and tumorigenicity. The analyzed metabolic features disclosed a role of CK2 in tumor metabolism, and suggest prominent functions for CK2 α isoform. Results were also confirmed by CK2 pharmacological inhibition. Overall, our study provides new information on the mechanism of cancer cells addiction to CK2 and on its isoform-specific functions, with fundamental implications for improving future therapeutic strategies based on CK2 targeting.

scholarly journals Experimental and Theoretical Studies of Sonically Prepared Cu–Y, Cu–USY and Cu–ZSM-5 Catalysts for SCR deNOx

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 824
Author(s):  
Przemysław J. Jodłowski ◽  
Izabela Czekaj ◽  
Patrycja Stachurska ◽  
Łukasz Kuterasiński ◽  
Lucjan Chmielarz ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Ultrasonic Irradiation ◽  
Active Phase ◽  
Spectroscopic Studies ◽  
In Situ Drifts ◽  
Ft Ir ◽  
Diffuse Reflectance Infrared ◽  
Experimental And Theoretical Studies

The objective of our study was to prepare Y-, USY- and ZSM-5-based catalysts by hydrothermal synthesis, followed by copper active-phase deposition by either conventional ion-exchange or ultrasonic irradiation. The resulting materials were characterized by XRD, BET, SEM, TEM, Raman, UV-Vis, monitoring ammonia and nitrogen oxide sorption by FT-IR and Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). XRD data confirmed the purity and structure of the Y/USY or ZSM-5 zeolites. The nitrogen and ammonia sorption results indicated that the materials were highly porous and acidic. The metallic active phase was found in the form of cations in ion-exchanged zeolites and in the form of nanoparticle metal oxides in sonochemically prepared catalysts. The latter showed full activity and high stability in the SCR deNOx reaction. The faujasite-based catalysts were fully active at 200–400 °C, whereas the ZSM-5-based catalysts reached 100% activity at 400–500 °C. Our in situ DRIFTS experiments revealed that Cu–O(NO) and Cu–NH3 were intermediates, also indicating the role of Brønsted sites in the formation of NH4NO3. Furthermore, the results from our experimental in situ spectroscopic studies were compared with DFT models. Overall, our findings suggest two possible mechanisms for the deNOx reaction, depending on the method of catalyst preparation (i.e., conventional ion-exchange vs. ultrasonic irradiation).

scholarly journals Spermine: Its Emerging Role in Regulating Drought Stress Responses in Plants

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 261
Author(s):  
Md. Mahadi Hasan ◽  
Milan Skalicky ◽  
Mohammad Shah Jahan ◽  
Md. Nazmul Hossain ◽  
Zunaira Anwar ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Stress Responses ◽  
Abiotic Stresses ◽  
Defense Mechanisms ◽  
Antioxidant Defense ◽  
Severe Drought ◽  
New Information ◽  
Effects Of Drought

In recent years, research on spermine (Spm) has turned up a lot of new information about this essential polyamine, especially as it is able to counteract damage from abiotic stresses. Spm has been shown to protect plants from a variety of environmental insults, but whether it can prevent the adverse effects of drought has not yet been reported. Drought stress increases endogenous Spm in plants and exogenous application of Spm improves the plants’ ability to tolerate drought stress. Spm’s role in enhancing antioxidant defense mechanisms, glyoxalase systems, methylglyoxal (MG) detoxification, and creating tolerance for drought-induced oxidative stress is well documented in plants. However, the influences of enzyme activity and osmoregulation on Spm biosynthesis and metabolism are variable. Spm interacts with other molecules like nitric oxide (NO) and phytohormones such as abscisic acid, salicylic acid, brassinosteroids, and ethylene, to coordinate the reactions necessary for developing drought tolerance. This review focuses on the role of Spm in plants under severe drought stress. We have proposed models to explain how Spm interacts with existing defense mechanisms in plants to improve drought tolerance.

scholarly journals Bianisotropic metasurfaces: physics and applications

Nanophotonics ◽  
2018 ◽  
Vol 7 (6) ◽  
pp. 1069-1094 ◽  
Author(s):  
Viktar S. Asadchy ◽  
Ana Díaz-Rubio ◽  
Sergei A. Tretyakov
Keyword(s):  
State Of The Art ◽  
Surface Current ◽  
Magnetic Surface ◽  
Magnetic Polarization ◽  
Research Directions ◽  
Magnetic Current ◽  
Asymmetric Reflection ◽  
Composite Layers ◽  
Electric And Magnetic Fields

AbstractMetasurfaces as optically thin composite layers can be modeled as electric and magnetic surface current sheets flowing in the layer volume in the metasurface plane. In the most general linear metasurface, the electric surface current can be induced by both incident electric and magnetic fields. Likewise, magnetic polarization and magnetic current can be induced also by external electric field. Metasurfaces which exhibit magnetoelectric coupling are called bianisotropic metasurfaces. In this review, we explain the role of bianisotropic properties in realizing various metasurface devices and overview the state-of-the-art of research in this field. Interestingly, engineered bianisotropic response is seen to be required for realization of many key field transformations, such as anomalous refraction, asymmetric reflection, polarization transformation, isolation, and more. Moreover, we summarize previously reported findings on uniform and gradient bianisotropic metasurfaces and envision novel and prospective research directions in this field.

scholarly journals Stark effect in low-dimensional hydrogen

2016 ◽  
Vol 93 (1) ◽  
Author(s):  
Thomas Garm Pedersen ◽  
Héctor Mera ◽  
Branislav K. Nikolić
Keyword(s):  
Stark Effect ◽  
Low Dimensional

Judgments of truth are independently modulated by affect and repetition

2021 ◽  
Author(s):  
Patricia Garrido-Vásquez ◽  
Tanja Rock
Keyword(s):  
Negative Affect ◽  
Positive Affect ◽  
Theoretical Perspective ◽  
Processing Fluency ◽  
Neutral Picture ◽  
Truth Effect ◽  
New Information ◽  
Affective Processes ◽  
Main Effect

People believe repeated statements more than new ones—the repetition-induced truth effect. It is prominently explained with processing fluency: The subjective ease of processing repeated versus new information. To date, the role of affective processes for the truth effect is rather unclear. From a theoretical perspective, people should rely more on fluency under positive than under negative affect. Here, we tested whether an affective picture presented before a statement influences the repetition-induced truth effect. Thirty-five participants took part in two sessions that were a week apart. In both sessions, they rated the truth status of statements. In session 2, repeated and new statements were intermixed, and each statement was preceded by a positive, negative, or neutral picture. We expected participants to rely more on fluency as a cue to truth in the positive than in the negative affective condition. However, although we replicated the repetition-induced truth effect, the interaction between affect and repetition was insignificant, but we observed a significant main effect of affect—statements were rated as truer after a positive rather than a negative or neutral picture. Our results suggest two independent mechanisms that enhance the subjective truth of statements: repetition and positive affect.

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