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51.
Michaël Gabay Nadia Brauner Vladimir Kotov 《4OR: A Quarterly Journal of Operations Research》2017,15(2):183-199
We use game theory techniques to automatically compute improved lower bounds on the competitive ratio for the bin stretching problem. Using these techniques, we improve the best lower bound for this problem to 19/14. We explain the technique and show that it can be generalized to compute lower bounds for any online or semi-online packing or scheduling problem. 相似文献
52.
Olga L. Mezentseva Galina B. Slepchenko Elena V. Dorozhko Eugenia S. Moiseeva Vladimir P. Kryukovskiy Nikolay K. Zaycev 《Electroanalysis》2023,35(4):e202200252
A highly sensitive electrochemical sensor based on arenediazonium tosylates was designed to detect meldonium in urine. The effect of the concentration of ArN2+OTs− arenediazonium tosylate modifier and various substituents was studied. Basic operating parameters for voltammetric meldonium detection were established and the procedure for urine sample preparation was developed. The following values were obtained: limit of detection (LOD) 0.005 mg ⋅ L−1 (P=0.95) and limit of quantification (LOQ) 0.01 mg ⋅ L−1. The relationship between the analytical signal and meldonium concentration in the solution ranging from 0.01 to 400 mg ⋅ L−1 was described by a linear function. The meldonium concentration error did not exceed 18 %. The analysis time for a single urine sample was reduced to 15 minutes. 相似文献
53.
Minkyu Kim Moon Jong Han Hansol Lee Paraskevi Flouda Daria Bukharina Kellina J. Pierce Katarina M. Adstedt Madeline L. Buxton Young Hee Yoon William T. Heller Srikanth Singamaneni Vladimir V. Tsukruk 《Angewandte Chemie (International ed. in English)》2023,62(30):e202305646
Chiral metal–organic frameworks (MOFs) have gained rising attention as ordered nanoporous materials for enantiomer separations, chiral catalysis, and sensing. Among those, chiral MOFs are generally obtained through complex synthetic routes by using a limited choice of reactive chiral organic precursors as the primary linkers or auxiliary ligands. Here, we report a template-controlled synthesis of chiral MOFs from achiral precursors grown on chiral nematic cellulose-derived nanostructured bio-templates. We demonstrate that chiral MOFs, specifically, zeolitic imidazolate framework (ZIF), unc -[Zn(2-MeIm)2, 2-MeIm=2-methylimidazole], can be grown from regular precursors within nanoporous organized chiral nematic nanocelluloses via directed assembly on twisted bundles of cellulose nanocrystals. The template-grown chiral ZIF possesses tetragonal crystal structure with chiral space group of P41, which is different from traditional cubic crystal structure of I-43 m for freely grown conventional ZIF-8. The uniaxially compressed dimensions of the unit cell of templated ZIF and crystalline dimensions are signatures of this structure. We observe that the templated chiral ZIF can facilitate the enantiotropic sensing. It shows enantioselective recognition and chiral sensing abilities with a low limit of detection of 39 μM and the corresponding limit of chiral detection of 300 μM for representative chiral amino acid, D- and L- alanine. 相似文献
54.
Miao Zhu Qin Zhou He Cheng Prof. Dr. Ye Sha Prof. Dr. Vladimir I. Bregadze Prof. Dr. Hong Yan Prof. Dr. Zhe Sun Prof. Dr. Xiang Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2023,135(1):e202213470
The combination of carbon-based nanohoops with other functional organic molecular structures should lead to the design of new molecular configurations with interesting properties. Here, necklace-like nanohoops embedded with carborane were synthesized for the first time. The unique deboronization of o-carborane has led to the facile preparation of ionic nanohoop compounds. Nanohoops functionalized by nido-o-carborane show excellent fluorescence emission, with a solution quantum yield of up to 90.0 % in THF and a solid-state quantum efficiency of 87.3 %, which opens an avenue for the applications of the nanohoops in OLEDs and bioimaging. 相似文献
55.
Sapozhnikova Irina M. Ulomsky Evgeny N. Rusinov Vladimir L. Chupakhin Oleg N. Stepanov Alexander V. Savateeva-Lyubimova Tatiana N. Sivak Konstantin V. 《Chemistry of Heterocyclic Compounds》2021,57(4):467-472
Chemistry of Heterocyclic Compounds - A series of azolo[5,1-c][1,2,4]triazines containing a cyano group were prepared as analogs of the drug Triazavirin (riamilovir). Sodium... 相似文献
56.
Krasnov Victor P. Zarubaev Vladimir V. Gruzdev Dmitry А. Vozdvizhenskaya Olga А. Vakarov Sergey А. Musiyak Vera V. Chulakov Evgeny N. Volobueva Alexandrina S. Sinegubova Ekaterina O. Ezhikova Marina А. Kodess Mikhail I. Levit Galina L. Charushin Valery N. 《Chemistry of Heterocyclic Compounds》2021,57(4):498-504
Chemistry of Heterocyclic Compounds - A number of novel amides were synthesized by coupling of 6-[(9H-purin-6-yl)amino]hexanoic acid to heterocyclic amines. The antiviral activity of the obtained... 相似文献
57.
Roman V. Tominov Zakhar E. Vakulov Vadim I. Avilov Daniil A. Khakhulin Nikita V. Polupanov Vladimir A. Smirnov Oleg A. Ageev 《Molecules (Basel, Switzerland)》2021,26(1)
We have experimentally studied the influence of pulsed laser deposition parameters on the morphological and electrophysical parameters of vanadium oxide films. It is shown that an increase in the number of laser pulses from 10,000 to 60,000 and an oxygen pressure from 3 × 10−4 Torr to 3 × 10−2 Torr makes it possible to form vanadium oxide films with a thickness from 22.3 ± 4.4 nm to 131.7 ± 14.4 nm, a surface roughness from 7.8 ± 1.1 nm to 37.1 ± 11.2 nm, electron concentration from (0.32 ± 0.07) × 1017 cm−3 to (42.64 ± 4.46) × 1017 cm−3, electron mobility from 0.25 ± 0.03 cm2/(V·s) to 7.12 ± 1.32 cm2/(V·s), and resistivity from 6.32 ± 2.21 Ω·cm to 723.74 ± 89.21 Ω·cm. The regimes at which vanadium oxide films with a thickness of 22.3 ± 4.4 nm, a roughness of 7.8 ± 1.1 nm, and a resistivity of 6.32 ± 2.21 Ω·cm are obtained for their potential use in the fabrication of ReRAM neuromorphic systems. It is shown that a 22.3 ± 4.4 nm thick vanadium oxide film has the bipolar effect of resistive switching. The resistance in the high state was (89.42 ± 32.37) × 106 Ω, the resistance in the low state was equal to (6.34 ± 2.34) × 103 Ω, and the ratio RHRS/RLRS was about 14,104. The results can be used in the manufacture of a new generation of micro- and nanoelectronics elements to create ReRAM of neuromorphic systems based on vanadium oxide thin films. 相似文献
58.
59.
Egor A. Kapitonov Natalia N. Petrova Vasilii V. Mukhin Leonid A. Nikiforov Vladimir D. Gogolev Ee Le Shim Aitalina A. Okhlopkova Jin-Ho Cho 《Molecules (Basel, Switzerland)》2021,26(4)
The physical and mechanical properties of nitrile–butadiene rubber (NBR) composites with N-cetylpyridinium bromide-carbon black (CPB-CB) were investigated. Addition of 5 parts per hundred rubber (phr) of CPB-CB into NBR improved the tensile strength by 124%, vulcanization rate by 41%, shore hardness by 15%, and decreased the volumetric wear by 7% compared to those of the base rubber-CB composite. 相似文献
60.
Vadim A. Dubskikh Anna A. Lysova Denis G. Samsonenko Alexander N. Lavrov Konstantin A. Kovalenko Danil N. Dybtsev Vladimir P. Fedin 《Molecules (Basel, Switzerland)》2021,26(5)
Three new 3D metal-organic porous frameworks based on Co(II) and 2,2′-bithiophen-5,5′-dicarboxylate (btdc2−) [Co3(btdc)3(bpy)2]·4DMF, 1; [Co3(btdc)3(pz)(dmf)2]·4DMF·1.5H2O, 2; [Co3(btdc)3(dmf)4]∙2DMF∙2H2O, 3 (bpy = 2,2′-bipyridyl, pz = pyrazine, dmf = N,N-dimethylformamide) were synthesized and structurally characterized. All compounds share the same trinuclear carboxylate building units {Co3(RCOO)6}, connected either by btdc2– ligands (1, 3) or by both btdc2– and pz bridging ligands (2). The permanent porosity of 1 was confirmed by N2, O2, CO, CO2, CH4 adsorption measurements at various temperatures (77 K, 273 K, 298 K), resulted in BET surface area 667 m2⋅g−1 and promising gas separation performance with selectivity factors up to 35.7 for CO2/N2, 45.4 for CO2/O2, 20.8 for CO2/CO, and 4.8 for CO2/CH4. The molar magnetic susceptibilities χp(T) were measured for 1 and 2 in the temperature range 1.77–330 K at magnetic fields up to 10 kOe. The room-temperature values of the effective magnetic moments for compounds 1 and 2 are μeff (300 K) ≈ 4.93 μB. The obtained results confirm the mainly paramagnetic nature of both compounds with some antiferromagnetic interactions at low-temperatures T < 20 K in 2 between the Co(II) cations separated by short pz linkers. Similar conclusions were also derived from the field-depending magnetization data of 1 and 2. 相似文献