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551.
VR Ermolaev GM Shub EP Kusina GL Polianski? VI Sobolev 《Canadian Metallurgical Quarterly》1976,10(3):53-58
Recovery of spatial resolving capacity (acuity) of central vision after temporary blindness induced by prolonged (1.5, 3, 6 min) light adaptation to a sun or incandescence lamp (20, 40, 80 thous. lux) illuminated white screen was studied. The recovery time increased exponentially with an increase in energy light stimulation (product of brightness of the deadapting source by the time of action). A general formula describing the relationship between the time of recovery of acuity and brightness of the test table and energy of light stimulus was derived. 相似文献
552.
A unique method has been introduced to measure the dielectric constant of polymer/ceramic composites using an effective medium instead of using the general methods of preparing bulk sintered pellets or films. In this work, a new and a simple method has been applied to measure the dielectric constant of polyvinyl cyanoethylate/barium titanate composites. The results are obtained by dispersing the ceramic powders in the polymer of a relatively low dielectric constant value. The dielectric constant of the composites is measured with varying ceramic volume percentages. The obtained results are compared with the many available theoretical models that are generally in practice to predict the dielectric constant of the composites. Then these results are extrapolated to comprehend the dielectric constant values of ceramic particles as these values form the base for the design of the composite. The precision and simplicity of the method can be exploited for predictions of the properties of nanostructure ferroelectric polymer/ceramic composites. 相似文献
553.
Maria G. Khrenova Tatiana V. Panova Vladimir A. Rodin Maxim A. Kryakvin Dmitrii A. Lukyanov Ilya A. Osterman Maria I. Zvereva 《International journal of molecular sciences》2022,23(15)
Nanopore sequencing (ONT) is a new and rapidly developing method for determining nucleotide sequences in DNA and RNA. It serves the ability to obtain long reads of thousands of nucleotides without assembly and amplification during sequencing compared to next-generation sequencing. Nanopore sequencing can help for determination of genetic changes leading to antibiotics resistance. This study presents the application of ONT technology in the assembly of an E. coli genome characterized by a deletion of the tolC gene and known single-nucleotide variations leading to antibiotic resistance, in the absence of a reference genome. We performed benchmark studies to determine minimum coverage depth to obtain a complete genome, depending on the quality of the ONT data. A comparison of existing programs was carried out. It was shown that the Flye program demonstrates plausible assembly results relative to others (Shasta, Canu, and Necat). The required coverage depth for successful assembly strongly depends on the size of reads. When using high-quality samples with an average read length of 8 Kbp or more, the coverage depth of 30× is sufficient to assemble the complete genome de novo and reliably determine single-nucleotide variations in it. For samples with shorter reads with mean lengths of 2 Kbp, a higher coverage depth of 50× is required. Avoiding of mechanical mixing is obligatory for samples preparation. Nanopore sequencing can be used alone to determine antibiotics-resistant genetic features of bacterial strains. 相似文献
554.
Reza Aminzadeh Abdou Khadir Fall Jérôme Sol Arno Thielens Philippe Besnier Maxim Zhadobov Nele De Geeter Prakash Parappurath Vasudevan Luc Dupré Roel Van Holen Luc Martens Wout Joseph 《Journal of Infrared, Millimeter and Terahertz Waves》2018,39(12):1264-1282
For the first time, a mm-wave personal exposure meter (mm-PEM) for the 5th generation of mobile networks (5G) exposure assessment in indoor diffuse fields is presented. The design is based on simulations and on-phantom calibration measurements in a mm-wave reverberation chamber (RC) at 60 GHz. The mm-PEM consists of an array of nine antennas on the body. Using the mm-PEM, the incident power density (IPD) is measured in the unloaded RC, for the antenna(s) on the phantom and RC loaded with phantom. The uncertainty of the mm-PEM is then determined in terms of its response, which is defined as the ratio of antenna aperture for the above measurement scenarios. Using nine antennas, the designed meter has a response of 1.043 (0.17 dB) at 60 GHz, which is very close to 1 (0 dB), the desired ideal response value. The mm-PEM measured an IPD of 96.6 W m??2 at 60 GHz in the RC, for an input power of 1 W. In addition, the average absorption cross-section of the phantom is determined as 225 cm2, which is an excellent agreement with its physical dimensions. 相似文献
555.
Petr M. Solyankin Mikhail N. Esaulkov Igor A. Chernykh Ivan V. Kulikov Maxim L. Zanaveskin Andrey R. Kaul Artem M. Makarevich Dmitrii I. Sharovarov Oleg E. Kameshkov Boris A. Knyazev Alexander P. Shkurinov 《Journal of Infrared, Millimeter and Terahertz Waves》2018,39(12):1203-1210
In this paper, we propose a switchable focuser device based on a Fresnel zone plate (FZP) structure for terahertz (THz) applications. Each FZP contains seven rings, etched in thin VO2 film with the designed focal lengths of 50 and 100 mm for 3.7-THz frequency. Temperature-induced VO2 phase transition leads to the change in dielectric susceptibility of the material, which allows one to switch on and off the focusing properties of the device. The devices were tested with radiation of 3.1 and 3.7 THz emitted by quantum cascade lasers. Experimental results were compared with numerical simulations. In this article, we compare the FZP based on VO2 films with different properties and show that a thicker VO2 film reveals higher focusing efficiency, while a thinner one reveals a higher modulation ratio for the peak intensity at the focal point of FZP. We demonstrate experimentally the near-diffraction-limited size of the beam in the focal point of the device. Switching between two phase states of the VO2 films results in up to the 38-fold change of intensity in the focal point. 相似文献
556.
Sol–gel derived CeO2/α‐Al2O3 bilayer thin film as an anti‐coking barrier and its catalytic coke oxidation performance 下载免费PDF全文
Hyuk T. Kwon Maxim P. Bukhovko Shilpa Mahamulkar Taylor Sulmonetti Byunghyun Min Qandeel Almas Andrzej Malek Liwei Li Pradeep K. Agrawal Christopher W. Jones 《American Institute of Chemical Engineers》2018,64(11):4019-4026
A CeO2/α‐Al2O3 bilayer was coated on a high temperature alloy (Incoloy 800H) by sol–gel dip‐coating and was evaluated for its potential as an anticoking barrier and coke oxidation catalyst. The bilayer effectively functioned as a barrier to metal surface catalyzed coking. The film prevented filamentous catalytic coking via blocking surface active metallic sites on the Incoloy substrate. Furthermore, the bilayer reduced the oxidation temperature of pyrolytic coke deposited on the film surface as compared to a bare oxidized Incoloy substrate, mostly owing to the oxidation catalytic activity of the CeO2 layer. Finally, it is demonstrated that the presence of the α‐Al2O3 buffer layer is critically important to the overall performance. Without the α‐Al2O3 layer, a CeO2 layer nearly completely lost both its barrier and oxidation catalytic functions. It is presumed that metallic species migrating from the substrate during high temperature treatments are responsible for the CeO2 deactivation, likely by blocking catalytic sites on the CeO2 surface. © 2018 American Institute of Chemical Engineers AIChE J, 64: 4019–4026, 2018 相似文献
557.
Because of the short range of alpha particles in tissue, the degree of uniformity of irradiation of the lung varies greatly depending on the form of the inhaled material. Animal studies have shown that the degree of dose uniformity influences the risk of lung cancer. This study investigates the radiation dose distribution of plutonium in human lung. Numerical maps of tissue configuration and target cell locations are obtained from histological sections of human lung tissue stained to enhance the identification of putative cell types for parenchymal lung cancers, i.e. alveolar type II cells and Clara cells. Monte Carlo simulations are used to obtain dose distribution around individual particles, and these distributions are used to compute dose distribution in volumes of lung tissue. Lung dose is characterised both by the degree of non-uniformity of irradiation and the relative degree of irradiation of all tissue versus the special cells of interest. 相似文献
558.
Janne Raula Annukka Kuivanen Anna Lhde Hua Jiang Maxim Antopolsky Jarno Kansikas Esko I. Kauppinen 《Journal of aerosol science》2007,38(12):1172-1184
Preparation of L-leucine nanoparticles by a process based on physical vapor deposition has been presented. In an aerosol flow reactor method, aqueous L-leucine droplets were first dried followed by the sublimation of L-leucine to produce vapor that upon vapor deposition resulted in L-leucine nanoparticles with size ranging from 40 to 200 nm. Onset temperature for the sublimation of L-leucine at concentrations from 0.02 to increased from 135 to , respectively. The formation of nanoparticles was initiated in three different ways: (i) via droplet drying, (ii) via heterogeneous nucleation of L-leucine vapor on solid L-leucine particles, and (iii) via homogeneous nucleation of L-leucine vapor to form new-born nanoparticles. Consequently, the saturation conditions of L-leucine vapor in the reactor determined the resulting particle size, size distribution and number concentration, those depending very much on nucleation mode. In general, the both nucleation modes produced narrow size distributions, that is, geometric standard deviation (GSD) was <1.8 although the number concentration increased with the increased amount of L-leucine vapor. Upon desublimation and vapor deposition, L-leucine formed leafy crystals whose size was the largest when produced from the heated section at the vicinity of the onset temperature and the smallest far above the onset temperature. All the particles prepared in the conditions (i)–(iii) were crystalline. However, X-ray diffraction analysis showed preferential direction for crystal growth according to the way of particle formation. 相似文献
559.
Goryachev M Galliou S Abbé P Komine V 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2011,58(11):2297-2304
A novel, simple method is proposed to increase the frequency stability of an oscillator. An additional negative feedback is used in combination with the positive loop of the harmonic oscillator to decrease the phase sensitivity to fluctuations of parameters other than the resonator. The main advantage of the proposed correction approach is that it does not require expensive external elements such as mixers or resonators. The validity of the method is theoretically demonstrated on a Colpitts oscillator using the control system theory approach and numerical simulations, and is experimentally verified with phase noise measurements of an actual oscillator-mockup. It is shown that the medium-term frequency stability can be easily improved by a factor of ten. 相似文献
560.
The World Health Organization recommends that the majority of water monitoring laboratories in the world test for E. coli daily since thermotolerant coliforms and E. coli are key indicators for risk assessment of recreational waters. Recently, we developed a new SNP method for typing E. coli strains, by which human-specific genotypes were identified. Here, we report the presence of these previously described specific SNP profiles in environmental water, sourced from the Coomera River, located in South East Queensland, Australia, over a period of two years. This study tested for the presence of human-specific E. coli to ascertain whether hydrologic and anthropogenic activity plays a key role in the pollution of the investigated watershed or whether the pollution is from other sources. We found six human-specific SNP profiles and one animal-specific SNP profile consistently across sampling sites and times. We have demonstrated that our SNP genotyping method is able to rapidly identify and characterize human- and animal-specific E. coli isolates in water sources. 相似文献