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91.
Tren’kin A. A. Almazova K. I. Belonogov A. N. Borovkov V. V. Gorelov E. V. Morozov I. V. Kharitonov S. Yu. 《Technical Physics》2021,66(2):243-249
Technical Physics - The evolution of a microsecond pulsed barrier discharge initiated in atmospheric pressure air in the point–plane electrode geometry has been investigated using streak... 相似文献
92.
Alena A. Nastulyavichus Irina N. Saraeva Andrey A. Rudenko Roman A. Khmelnitskii Alexander L. Shakhmin Demid A. Kirilenko Pavel N. Brunkov Nikolay N. Melnik Nikita A. Smirnov Andrey A. Ionin Sergey I. Kudryashov 《Particle & Particle Systems Characterization》2020,37(5):2000010
Si nanoparticles (NPs), which are innovative promising light-harvesting components of thin-film solar cells and key-enabling biocompatible theranostic elements of infrared-laser and radiofrequency hyperthermia-based therapies of cancer cells in tumors and metastases, are significantly advanced in their near/mid-infrared band-to-band and free-carrier absorption via donor sulfur-hyperdoping during high-throughput facile femtosecond-laser ablative production in liquid carbon disulfide. High-resolution transmission electron microscopy and Raman microscopy reveal their mixed nanocrystalline/amorphous structure, enabling the extraordinary sulfur content of a few atomic percents and very minor surface oxidation/carbonization characterized by energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. A 200-nm thick layer of the nanoparticles exhibits near−mid-infrared absorbance, comparable to that of the initial 380-micron thick n-doped Si wafer (phosphor-dopant concentration ≈1015 cm−3), with the corresponding extinction coefficient for the hyperdoped NPs being 4–7 orders higher over the broadband spectral range of 1–25 micrometers. Such ultimate, but potentially tunable mid-IR structured, multi-band absorption of various sulfur-impurity clusters and smooth free-carrier absorption are break through advances in mid-infrared (mid-IR) laser and radiofrequency (RF) hyperthermia-based therapies, as envisioned in the RF-heating tests, and in fabrication of higher-efficiency thin-film and bulk photovoltaic devices with ultra-broad (UV−mid-IR) spectral response. 相似文献
93.
94.
Polina Kapitanova Esmaeel Zanganeh Nikita Pavlov Mingzhao Song Pavel Belov Andrey Evlyukhin Andrey Miroshnichenko 《Annalen der Physik》2020,532(12):2000293
The existence of non-radiating electromagnetic sources attracts much attention in photonic community and gives rise to extensive discussions of various applications in lasing, medical imaging, sensing, and nonlinear optics. In this article, the existence of magnetic anapole states (or magnetic-type non-radiating sources) characterized by a suppressed magnetic dipole radiation in a dielectric cylindrical particle is theoretically predicted and experimentally demonstrated. The specific features of the magnetic anapole state under ideal conditions are identified, followed by a demonstration of how their existence can be detected in practical structures. The concept is valid in various frequency bands from visible range for nanoparticles to microwave range for millimeter size objects. The experimental study is performed in microwave frequency range which allows not only to measure the far-field (scattered field) characteristics, but also to probe the peculiar field profile directly inside the dielectric particle. The experimental results agree well with the analytical ones and pave the way to detect and identify nontrivial different-type anapole states. 相似文献
95.
Maksim Kulichenko Nikita Fedik Prof. Dr. Konstatin V. Bozhenko Prof. Dr. Alexander I. Boldyrev 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(20):5311-5315
Growing demands of material science and, in particular, in the field of nonlinear optics (NLO) encourage us to look for stable highly polarizable molecules with excess diffuse electrons. An unusual class of compounds called electrides comply with these requirements. Many attempts have been made, yet only few electrides have been synthesized as solids and none of them as molecular species. In this paper, a new theoretically designed molecular species with electride characteristics is reported. The idea of this molecular electride comes from the formation of electride-like features in the MgO crystal with defect F-centers. The geometry of the investigated molecule can be described as a Mg4O4 cube with one oxygen atom removed. In Mg4O3, two 3s electrons are pushed out from the inner area of the molecule forming a diffuse electride multicentered bond. Our calculations show that this electride-like cluster possesses a noticeably large first hyperpolarizability β=5733 au. At the same time, a complete cube Mg4O4 and Mg4O32+ without electride electron pair have much smaller β: 0 au and 741 au, respectively. This fact indicates the decisive role of the electride electron pair in NLO properties. Additionally, vertical detachment energies of isomers (VDE), excitation energies ΔE, polarizabilities α, and IR spectra were calculated. These properties, including β, are supposed to be observable experimentally and can serve as indirect evidence of the stable molecular electride formation. 相似文献
96.
97.
Nikita O. Shaparenko Nikolay B. Kompan'kov Marina G. Demidova Alexander I. Bulavchenko 《Electrophoresis》2020,41(18-19):1592-1599
The structure and conductivity of AOT (sodium bis(2-ethylhexyl) sulfosuccinate) solutions (2.5 × 10−4–2.5 × 10−1 M) in n-hexadecane-chloroform mixture at the chloroform concentration from 50 to 100 vol% were studied. The diffusion ordered spectroscopy NMR study revealed that in the indicated range, the observed hydrodynamic diameter of micelles depends only on the AOT concentration and does not depend on the chloroform content. Molar fractions of free AOT molecules and those aggregated into micelles were calculated using the Lindman's law: at concentrations above 2.5 × 10−1 М, the solutions contain mostly the micelles, whereas at concentrations below 2.5 × 10−4 M, the solutions contain AOT molecules. The transition region contains both the AOT molecules and the micelles. Conductivity measurements were used to determine free charge carriers in the bulk of solutions and their contributions to conductivity. 相似文献
98.
99.
Gaoxiang Liu Nikita Fedik Chalynette Martinez‐Martinez Sandra M. Ciborowski Xinxing Zhang Alexander I. Boldyrev Kit H. Bowen 《Angewandte Chemie (International ed. in English)》2020,59(23):8760-8764
We reply to the comment by S. Pan and G. Frenking who challenged our interpretation of the Na?:→BH3 dative bond in the recently synthesized NaBH3? cluster. Our conclusion remains the same as that in our original paper ( https://doi.org/10.1002/anie.201907089 and https://doi.org/10.1002/ange.201907089 ). This conclusion is additionally supported by the energetic pathways and NBO charges calculated at UCCSD and CASMP2(4,4) levels of theory. We also discussed the suitability of the Laplacian of electron density (QTAIM) and Adaptive Natural Density Partitioning (AdNDP) method for bond type assignment. It seems that AdNDP yields more sensible results. This discussion reveals that the complex realm of bonding is full of semantic inconsistencies, and we invite experimentalists and theoreticians to elaborate this topic and find solutions incorporating different views on the dative bond. 相似文献
100.
Jikun Li Xinxin Feng Wei Zhu Nikita Oskolkov Tianhui Zhou Boo Kyung Kim Noman Baig Prof. Michael T. McMahon Prof. Eric Oldfield 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(1):264-271
Diamagnetic chemical exchange saturation transfer (CEST) contrast agents offer an alternative to Gd3+‐based contrast agents for MRI. They are characterized by containing protons that can rapidly exchange with water and it is advantageous to have these protons resonate in a spectral window that is far removed from water. Herein, we report the first results of DFT calculations of the 1H nuclear magnetic shieldings in 41 CEST agents, finding that the experimental shifts can be well predicted (R2=0.882). We tested a subset of compounds with the best MRI properties for toxicity and for activity as uncouplers, then obtained mice kidney CEST MRI images for three of the most promising leads finding 16 (2,4‐dihydroxybenzoic acid) to be one of the most promising CEST MRI contrast agents to date. Overall, the results are of interest since they show that 1H NMR shifts for CEST agents—charged species—can be well predicted, and that several leads have low toxicity and yield good in vivo MR images. 相似文献