7,406 research outputs found
An Overview of Computational Studies on Colloidal Semiconductor Nanocrystals
Full text linkIn the last two decades, colloidal semiconductor nanocrystals have emerged as a phenomenal research topic due to their size-dependent optoelectronic properties and to their outstanding versatility in many technological applications. In this review, we provide an historical account of
the most relevant computational works that have been carried out to understand atomistically the electronic structure of these materials, including the main requirements needed for the preparation of nanocrystal models that align well with the experiments. We further discuss how the advancement
of these computational tools has affected the analysis of these nanomaterials over the years. We focus our review on the three main families of colloidal semiconductor nanocrystals: group II-VI and IV-VI metal chalcogenides, group III-V metal pnictogenides and metal halides, in particular
lead-based halide perovskites. We discuss the most recent research frontiers and outline the future outlooks expected in this field from a computational perspective
Yuriy Hryvniak as a researcher of the biography of Ivan Puluj
Full text linkМатеріал тез присвячено дослідженню сторінок біографії
Юрія Гривняка - автора монографії про Івана Пулюя, яку було
опубліковано 1971 року у Лондоні завдяки фінансовій підтримці Союзу
українців у Великій Британії. Автором було використано ряд фото та
архівних матеріалів, отриманих від О. Пулюя. На жаль, творчість і
життєвий шлях Ю. Гривняка є маловідомими в Україні, а доля зібраних
ним джерел потребує фахового дослідженняThese theses are devoted to the study of the pages of Yuriy
Hryvniak’s biography. He was the author of a monograph dedicated to the study
of the life and activities of the famous Ukrainian scientist and public figure Ivan
Puluj. The author used a number of photos and archival materials received from
O. Puluj. Unfortunately, the creativity and life path of Y. Hryvniak is little
known in Ukraine, and the fate of the sources collected by him requires
professional researc
Note from David Kirchman to Ivan Valiela at the Ecosystems Center
No full textTitle page of the book "Processes in Microbal Ecology". The author, David L. Kirchman, has written a note to Ecosystems Center scientist Ivan Valiela.Note reads: "Ivan- You & the MBL Marine Ecology course got me going in this field. Thanks. David Kirchman"photograph
Ivan Žuvela Šabo and His Etnographic Record from 1892
Full text linkU ovom tekstu otkriva se identitet autora jednog starijeg etnografskog zapisa nastalog na otoku Korčuli. Riječ je o rukopisu „Narodne pjesme junačke i žetelačke“ iz 1892., a koji se čuva u Arhivu Odsjeka za etnologiju Hrvatske akademije znanosti i umjetnosti u Zagrebu. Iako je u tom rukopisu autor potpisan kao „Ivan Žuvela, pravnik“, dosada ga se nije moglo točnije identificirati, iznesena je kriva pretpostavka, a čak se i spekuliralo da je riječ o pseudonimu. Istraživanjem dostupnih izvora i novinskih zapisa ipak se utvrdilo kako je zaista riječ o Velolučaninu Ivanu Žuveli iz grane Šabo, studentu prava koji je umro u svojoj 23-oj godini života, samo godinu dana po nastanku ovog rukopisa. Uz autora, u tekstu se detaljno progovara o rukopisu i njegovom iznimnom značaju za proučavanje nekadašnje svakodnevice, a posebno žetelačkih običaja na zapadnom dijelu otoka Korčule.This text reveals the identity of the hitherto unknown author one of the oldest known ethnographic record from the island of Korčula. The manuscript titled “Narodne pjesme junačke i žetelačke” (Folk Songs of Heroes and Harvesters) dates back to 1892 and is preserved in the Archive of the Ethnology Division at the Croatian Academy of Sciences and Arts in Zagreb. Although the author of the manuscript is signed as “Ivan Žuvela, legal scholar,” his precise identification has remained elusive, with incorrect assumptions and even speculation about a possible pseudonym. Through research of available sources and newspaper records, it has now been conclusively determined that the author is indeed Ivan Žuvela from Vela Luka, a member of the Šabo family, and a law student who passed away at the age of 23, just a year after creating this manuscript. In addition to introducing the author, this text provides a detailed exploration of the manuscript and its exceptional significance for studying the everyday life of the past, particularly the harvesting customs on the western part of the island of Korčula
Riflessioni su "Note su una teoria d'impresa" di Ivan Snehota
No full textIl capitolo ripercorre, riassume e discute i lavori scientifici del prof. Ivan Snehota a partire dalla monografia "Note su una teoria d'impresa" che contiene le basi del suo pensiero e del futuro lavoro di ricerca. Traendo spunto dagli studi del prof. Snehota l'Autore suggerisce percorsi di sviluppo della ricerca sulle reti tra imprese.The chapter summarizes and debates Emeritus prof. Ivan Snehota's studies since his Ph.D thesis. Following such an analysis the author suggests future research directions on the topic of business networks
Ligand dynamics on the surface of CdSe nanocrystals
No full textSynthesis protocols of colloidal semiconductor nanocrystals (NCs) comprise the coordination of the semiconductive inorganic core by a layer of organic ligands, which play a crucial role in stabilizing the NCs in organic solvents. Understanding the distribution, binding and mobility of ligands on the different NC facets is key to prevent the formation of surface defects and to optimize the overall optoelectronic efficiency of these materials. In this paper, we employed classical molecular dynamics (MD) simulations to shed light on the plausible locations, binding modes and mobilities of carboxylate ligands on the different facets of CdSe nanocrystals. Our results suggest that these features are influenced by the temperature of the system and the coordination number of the surface (Cd and Se) atoms. High ligand mobilities and structural rearrangements are linked to a low coordination of the Cd atoms. Undercoordinated Se atoms, which are considered the culprit of hole trap states in the bandgap of the material, are instead found to spontaneously form on the nanosecond timescale, making them likely candidates for an efficient photoluminescence quenching mechanism.</p
Classical Force Field Parameters for InP and InAs Quantum Dots with Various Surface Passivations
No full textClassical molecular dynamics (MD) simulations on realistic colloidal quantum dot (QD) systems are often hampered by missing force field (FF) parameters for an accurate description of the QD-ligand interface. However, such calculations are of major interest, specifically for studying the surface chemistry of colloidal nanocrystals. In this work, we have utilized a previously published stochastic optimization algorithm to obtain FF parameters for InP and InAs QDs capped by Cl, amine, carboxylate, and thiolate ligands. Our FF parameters are interfaced with well-established FFs for organic molecules, allowing for the simulation of InP and InAs QDs with a broad range of organic ligands in explicit apolar solvents. The quality of our FF parameters was assessed by comparing properties of the classical MD simulations with ab initio MD simulations and experimental and theoretical values from the literature
The chemiionization reactions Ce+O and Ce+O2: assignment of the observed chemielectron bands
No full textMulticonfigurational quantum chemical methods (CASSCF/CASPT2) have been used to study the chemiionization reactions Ce + O CeO+ + e- and Ce + O2 CeO + e-. Selected spectroscopic constants for CeOn and CeO (n = 1, 2), as well as reaction enthalpies of the chemiionization reactions of interest, have been computed and compared with experimental values. In contrast to the lanthanum case, for both Ce + O2(X3) and Ce + O2( a1g), the Ce + O2 CeO + e- reaction is shown to be exothermic, and thus, contributes to the experimental chemielectron spectra. The apparent discrepancy between the computed reaction enthalpies and the high kinetic energy offset values measured in the chemielectron spectra is rationalized by arguing that chemielectrons are produced mainly via two sequential reactions (Ce + O2 CeO + O, followed by Ce + O CeO+ + e-) as in the case of lanthanum. For Ce + O2 (a1g), a chemielectron band with higher kinetic energy than that recorded for Ce + O2( X3) is obtained. This is attributed to production of O( 1D) from the reaction Ce + O2( a1g) CeO + O( 1D), followed by chemiionization via the reaction Ce + O( 1D) CeO+ + e-. Accurate potential energy curves for the ground and a number of excited states of CeO and CeO+ have been computed, and a mechanism for the chemiionization reactions investigated experimentally was proposed
Towards an Augmented Reality Game for Learning about Ivan Vazov's Literary Works
Full text linkThis paper presents a concept for a serious game based on an augmented reality representation of a mural artwork located in the National Library
“Ivan Vazov” in Plovdiv, Bulgaria. The mural features the renowned Bulgarian author Ivan Vazov in the center, surrounded by characters from his literary works.
By using a head-mounted display in front of the mural, the players would see movement of the characters and will be able to interact with them in a gamified augmented reality environment. The serious game proposed in this paper offers a solution to the engagement of players with literature and textual heritage within a broader cultural context
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