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排序方式: 共有468条查询结果,搜索用时 15 毫秒
451.
V. I. Moshkin 《Russian Electrical Engineering》2013,84(8):466-469
The size range of a holding area that helps to generate and modify the anchor holding force during starting-up of a linear electromagnetic motor with an integrated holding device is determined. 相似文献
452.
Alexandr A. Bogdashov Yury V. Rodin 《Journal of Infrared, Millimeter and Terahertz Waves》2007,28(8):627-638
Particle Swarm Optimization (PSO) is an effective, simple and promising method intended for the fast search in multi-dimensional space [Kennedy and Eberhart, "Particle Swarm Optimization", Proc. of the 1995 IEEE International Conference on Neural Networks, 1995]. Besides special testing problems a number of engineering tasks of electrodynamics were solved by the PSO successfully [Robinson and Rahmat-Samii, "Particle Swarm Optimization in Electromagnetics", IEEE Trans. Antennas Propag., 2004; Jin and Rahmat-Samii, "Parallel Particle Swarm Optimization and Finite-Difference Time-Domain (PSO/FDTD) Algorithm for Multband and Wide-Band Patch Antenna Designs", IEEE Trans. Antennas Propag., 2005]. On the other hand, the scattering matrix technique is a fast and accurate method of mode converter analysis. We illustrate PSO by a number of converter designs developed for high-power microwaves control: a matching horn for output maser section, a corrugated converter of linear-polarized hybrid modes, a TE01 mitre bend. 相似文献
453.
Hadjar O Wang P Futrell JH Dessiaterik Y Zhu Z Cowin JP Iedema MJ Laskin J 《Analytical chemistry》2007,79(17):6566-6574
A new ion deposition apparatus was designed and constructed in our laboratory. Our research objectives were to investigate interactions of biomolecules with hydrophilic and hydrophobic surfaces and to carry out exploratory experiments aimed at highly selective deposition of spatially defined and uniquely selected biological molecules on surfaces. The apparatus includes a high-transmission electrospray ion source, a quadrupole mass filter, a bending quadrupole that deflects the ion beam and prevents neutral molecules originating in the ion source from impacting the surface, an ultrahigh vacuum (UHV) chamber for ion deposition by soft landing, and a vacuum lock system for introducing surfaces into the UHV chamber without breaking vacuum. Ex situ analysis of surfaces following soft landing of mass-selected peptide ions was performed using 15 keV Ga+ time-of-flight secondary ion mass spectrometry and grazing incidence infrared reflection-absorption spectroscopy. It is shown that these two techniques are highly complementary methods for characterization of surfaces prepared with a range of doses of mass-selected biomolecular ions. We also demonstrated that soft landing of peptide ions on surfaces can be utilized for controlled preparation of peptide films of known coverage for fundamental studies of matrix effects in SIMS. 相似文献
454.
V. I. Moshkin A. V. Desyatov N. P. Kakurkin 《Theoretical Foundations of Chemical Engineering》2007,41(6):816-821
Experimental data on the fluid dynamics, temperature fields, and mass transfer in industrial spray dryers for synthetic detergents are reported. The distribution of the components of the flow velocity in the radial cross-section of a turbulent swirl flow in the active drying zone is obtained on the basis of balance equations and experimental data. The radial hydrodynamic stability interval of 0.2 < r/R < 0.9 is calculated using the Howard hydrodynamic stability criterion. The results are used to optimize the operation of an industrial dryer with a dry-product rate of 15 t/h. 相似文献
455.
456.
Pasquale F. Fulvio Richard T. Mayes Xiqing Wang Shannon M. Mahurin John C. Bauer Volker Presser John McDonough Yury Gogotsi Sheng Dai 《Advanced functional materials》2011,21(12):2208-2215
Mesoporous carbon materials do not have sufficient ordering at the atomic scale to exhibit good electronic conductivity. To date, mesoporous carbons having uniform mesopores and high surface areas have been prepared from partially‐graphitizable precursors in the presence of templates. High temperature thermal treatments above 2000 °C, which are usually required to increase conductivity, result in a partial or total collapse of the mesoporous structures and reduced surface areas induced by growth of graphitic domains, limiting their applications in electric double layer capacitors and lithium‐ion batteries. In this work, we successfully implemented a “brick‐and‐mortar” approach to obtain ordered graphitic mesoporous carbon nanocomposites with tunable mesopore sizes below 850 °C without using graphitization catalysts or high temperature thermal treatments. Phenolic resin‐based mesoporous carbons act as mortar to highly conductive carbon blacks and carbon onions (bricks). The capacitance and resistivity of final materials can be tailored by changing the mortar to brick ratios. 相似文献
457.
Carbide‐derived carbons (CDCs) are a large family of carbon materials derived from carbide precursors that are transformed into pure carbon via physical (e.g., thermal decomposition) or chemical (e.g., halogenation) processes. Structurally, CDC ranges from amorphous carbon to graphite, carbon nanotubes or graphene. For halogenated carbides, a high level of control over the resulting amorphous porous carbon structure is possible by changing the synthesis conditions and carbide precursor. The large number of resulting carbon structures and their tunability enables a wide range of applications, from tribological coatings for ceramics, or selective sorbents, to gas and electrical energy storage. In particular, the application of CDC in supercapacitors has recently attracted much attention. This review paper summarizes key aspects of CDC synthesis, properties, and applications. It is shown that the CDC structure and properties are sensitive to changes of the synthesis parameters. Understanding of processing–structure–properties relationships facilitates tuning of the carbon material to the requirements of a certain application. 相似文献
458.
Dmitry V. Bagrov Grigory S. Glukhov Andrey V. Moiseenko Maria G. Karlova Daniil S. Litvinov Petr А. Zaitsev Liubov I. Kozlovskaya Anna A. Shishova Anastasia A. Kovpak Yury Y. Ivin Anastasia N. Piniaeva Alexey S. Oksanich Viktor P. Volok Dmitry I. Osolodkin Aydar A. Ishmukhametov Alexey M. Egorov Konstantin V. Shaitan Mikhail P. Kirpichnikov Olga S. Sokolova 《Microscopy research and technique》2022,85(2):562-569
The severe COVID-19 pandemic drives the research toward the SARS-CoV-2 virion structure and the possible therapies against it. Here, we characterized the β-propiolactone inactivated SARS-CoV-2 virions using transmission electron microscopy (TEM) and atomic force microscopy (AFM). We compared the SARS-CoV-2 samples purified by two consecutive chromatographic procedures (size exclusion chromatography [SEC], followed by ion-exchange chromatography [IEC]) with samples purified by ultracentrifugation. The samples prepared using SEC and IEC retained more spikes on the surface than the ones prepared using ultracentrifugation, as confirmed by TEM and AFM. TEM showed that the spike (S) proteins were in the pre-fusion conformation. Notably, the S proteins could be recognized by specific monoclonal antibodies. Analytical TEM showed that the inactivated virions retained nucleic acid. Altogether, we demonstrated that the inactivated SARS-CoV-2 virions retain the structural features of native viruses and provide a prospective vaccine candidate. 相似文献
459.
Shetnev Anton Andreevich Baykov Sergey Valentinovich Smirnov Alexey Vladimirovich Dorogov Mikhail Vladimirovich Novozhilov Yury Vladimirovich 《化学与化工:英文版》2014,(9):865-869
The pilot-scale process for preparing 2-amino-6-chloro-9-(2',3',5'-tri-O-acetyl-Dq3-ribofuranosyl)-purine and 2-chloroadenosine has been developed with a total yield of the desired compounds 73% and 44.5%, respectively. These compounds are useful intermediates for enzymatic synthesis of active pharmaceutical ingredients Nelarabine and Cladribine. The starting material--commercially avaliable guanosine--was acetylated with acetic anhydride, yielding 2,3,5-tri-O-acetylguanosine, which was further deoxyhalogenated with phosphorous oxychloride in presence of tetraethylammonia chloride. Diazotization of the resulting intermediate with tert-butylnitrite leads to the corresponding ribofuranosyl-substituted 2,6-dichloropurine, which was converted to 6-chloroadenosine by reaction with methanolic ammonia. 相似文献
460.
ABSTRACT: A comparative photoluminescence analysis of as-prepared and chemically modified (by alkyl chains -C18H37) silicon and carbon nanoparticles dispersed in low-polar liquids is reported. Influence of the low-polar liquid nature and ambient temperature on photoluminescence of the nanoparticles has been investigated from the point of view of their possible application as thermal nanoprobes. 相似文献