Добірка наукової літератури з теми "Semicore state"

This study, with experiments and comparisons, aims to analyze the difference of stainless (SUS316L) microtubes in the flaring forming among dies with various semicone angles (35°, 40°, 45°, 50°, and 55°). The flow rule by Prandtl-Reuss combined with the finite element deformation theory and updated Lagrangian formulation (ULF) is applied to establish the finite element analysis equation for an incremental elastoplastic deformation to simulate the microtube flaring process. The broadrminalgorithm is utilized in the forming process for the elastoplastic state and die contact. The simulation data allow acquiring the deformation traceability, the relationship between punch load and punch stroke, the distribution of stress and strain, the distribution of the thinnest thickness resulted from dies with different semicone angles, and the distribution of flaring radius caused by dies with distinct semicone angles in the forming process. The experimental result presents similar results to the relationship between punch load and punch stroke and the simulation of the coefficient of frictionμ=0.05, revealing the analysis being suitable for the analysis of microtube cone angle flaring process. The analysis and experimental results show that the thinnest thickness of the microtube increases with increasing semicone angles of dies and the maximal flaring radius of microtubes increases with increasing semicone angles of dies.

The thermogravimetric method was applied to study the combustion characteristics of waste plastics and semicoke mixture at different heating rates with temperature ranging from room temperature to 1173 K. Also, the kinetic parameters of combustion process were also estimated by fitting the experimental data to the calculated data. The results showed that the mixed combustion process of waste plastics and semicoke could be divided into volatile combustion stage and fixed carbon combustion stage. The addition of waste plastics could increase the comprehensive combustion characteristic index (S) and flammability index (C). It showed synergistic effect in the mixed combustion process. When the additive amount of waste plastics was 60%, the S value and C value reached peak point at the heating rate of 20 K/min. The heating rate had a promotion effect on combustion rate. The mixed combustion process of waste plastics and semicoke could be well simulated by the n-order rate model of double parallel reactions. The activation energies E in the first stage of combustion of the mixture were higher than that in the second stage, and the preexponential factor k was opposite. Meanwhile, a marked kinetic compensation effect was presented between the activation energy and the preexponential factor.

The thermal behavior of coal tar refined soft pitch (CTRSP) was investigated by using polarizing microscope with heating stage and thermogravimetric analyzer. The phenomena of carbonization regime process of CTRSP were observed directly in the micro-picture taken online. The results showed that the carbonization thermal dynamic process of CTRSP is divided into several typical stages. At 30-250°C,there is small molecular evaporation; at 250-390 °C,there is thermal decomposition and small molecular evaporation; at 390-480°C,there is the condensation of small molecules and radicals into macromolecules and directional arrangement generating small spheres; at 480-520°C,there is the coking stage; at 520-560°C, there is the semicokes dehydrogenation and shrinkage. The spherules are formed at about 390°C. The growth process of the spherules is divided into several stages: absorption optical isotropic matrix asphalt to grow, two spherule collision fusion and growth, finally (at 480-520°C) due to gravity is greater than surface tension small spheroid disintegration deformation and became fibrillar semicoke (at 520-560 °C). Thermogravimetric (TG) - differential thermogravimetry (DTG) curve are treated by Freeman-Carrolls non isothermal differential method, coal tar soft pitchs first-order reaction is from 253°C to 325°C, from 370 °C to 413°C two temperature stages, activation energy is 28.575 kJ/mol and 60.210 kJ/mol, pre-exponential factor is 2.328×106and 1.4833×107, respectively. The microscopic picture recording was consistent with thermal heavy kinetic equation and the results confirmed that the chief of thermal decomposition reaction is operated from 253 °C to 325 °C, the most of condensation polymerization reaction is operated from 370 °C to 413 °C.

Continuous sugar centrifugal is used to separate sugar and molasses from massecuite. The centrifugal basket is pierced with numerous holes to allow the molasses to escape and is lined with metal gauze, which serves to retain the sugar while allowing the molasses to pass through. The centrifugal basket is conical in shape (Fig. 1), runs at a constant speed in the range 1200 to 2200 rpm., and is fed by a continuous stream of material. The semicone angle α varies from 25 deg to 35 deg. What prompted this investigation is a fairly high level of working stress experienced in commerically available centrifugals, often close to yield stress. This technical brief presents the steady state stress distribution patterns in these centrifugals using a fairly accurate model. Since the problem under consideration is cyclic, a symmetric model using the finite element method with triangular shell elements is employed to determine the stresses and displacements. Besides, the critical speeds of the baskets have also been computed using Rayleigh’s method.

We start by investigating the arising of a spin-orbit coupling and a Darwin-type term that stem from Lorentz symmetry breaking effects in the CPT-odd sector of the Standard Model Extension. Then, we establish a possible scenario of the violation of the Lorentz symmetry that gives rise to a linear confining potential and an effective electric field in which determines the spin-orbit coupling for a neutral particle analogous to the Rashba coupling [E. I. Rashba, Sov. Phys. Solid State 2, 1109 (1960)]. Finally, we confine the neutral particle to a quantum dot [W.-C. Tan and J. C. Inkson, Semicond. Sci. Technol. 11, 1635 (1996)] and analyze the influence of the linear confining potential and the spin-orbit coupling on the spectrum of energy.

Metallurgical fuel, including various types of mineral fuels: coke, hard coal, brown coal, peat, combustible shales and products of their technological conversion – needs environmental control of their use safety. When burning metallurgical fuel, harmful substances fall into the environment such as chlorine, fluorine, sulfur, arsenic, which worsen the environmental situation. Technical regulations on the safety of coal products contain requirements to limit the content of harmful impurities and their maximum permissible concentrations. Due to the wide spread of fluorine in natural and technological objects and the high toxicity of its compounds, the control of fluorine content is an urgent problem in the industrial use of metallurgical fuel. Physical methods for the determination of fluorine in solid fuel based on excitation of different spectra of the studies allow to identify it without decomposition directly in the source solid material, however, they have several limitations (sensitivity, accuracy of definition, complexity of hardware design). In other methods, mainly in ionchromatography and ionometry, samples are decomposed and fluorine is transferred into the solution. High temperature processes: pyrohydrolysis and combustion melting are usually used for decomposition. The aim of this work was to create a selective method for ionometric determination of fluorine with a fluoride-selective electrode. The study objects were samples of coal: brown, gas, semicoke, coke nut. Effective decomposition of the samples by two-stage high-temperature melting with KNaCO3 is proposed. Hydrolysis coprecipitation of accompanying interfering cations with chloride iron (II) was carried out for fluorine discharge in the solution in the form of free fluoride. The procedure of decomposition and ionometric determination of fluorine is described. The estimation of trueness and reproducibility of the developed technique by the method of sample variation was carried out. Fluorine content in the studied samples did not exceed the limit- tolerance values for commercial samples of coal products, which indicates the environmental safety of the samples in their subsequent energy application. The developed method is promising for the control of fluorine impurity in metallurgical fuel and is characterized by selectivity and simple carrying out.

Kostryukova AM, Mashkova V, Krupnova TG, Egorov NO. 2018. Phytoplankton biodiversity and its relationship with aquatic environmental factors in Lake Uvildy, South Urals, Russia. Biodiversitas 19: 1422-1428. Lake Uvildy is one of the largest and the most unique of the South Ural region lakes. This mountain deep lake, which has the status of a natural monument. The purpose of this paper was to study the phytoplankton community structure and the aquatic environmental factors in Lake Uvildy. The phytoplankton samples were collected from 5 sites of Lake Uvildy, then filtered through the plankton net and were preserved in 5% formalin. Species were identified using the handbooks by Sladecek, Yarushina, and Al-Kandari. Water samples were taken for water quality analysis. The several physicochemical parameters were measured in situ by a Portable Meters (Multitest IPL-513 and Multitest KSL-111, Semico Ltd, Russia, Novosibirsk). The others parameters were measured in the laboratory of the Department of Chemistry of the South Ural State University according to the standard methods. The sampling was made during the vegetation period in June-July 2014. The water quality was evaluated using the Shannon biodiversity index. A total of 38 species (11 phyla, 31 genera), including 9 species of Chlorophyta, 13 species of Bacillariophyta, 9 species of Cyanophyta, 4 species of Euglenophyta, 2 species of Chrysophyta, 1 species of Dinophyta, were identified. The phytoplankton species in the lake were mainly represented by Cyanophyta and Bacillariophyta. There were 5 dominant species: Fragilaria crotonensis, Asterionella formosa, Dolichospermum lemmermannii, Microcystis aeruginosa, and Coenococcus planktonicus. The Shannon index value comprised 1.27-2.21. According to the saprobity index values (1.63-2.35), the water in the late is evaluated as satisfactorily clean. Physico-chemical parameters were factors driving the change in phytoplankton community composition in Lake Uvildy.

We really like pores in our research group. Big pores, small pores, ordered pores, random pores – they all have a function and as is often found, show behaviour that is not always predicted. I started my research journey trying to put extremely thin films onto near-perfect III-V crystals to control (opto)electronic properties and when the first TEM on our campus showed the image in Fig. 1 almost 21 years ago (1,2), the electrochemical modification of the InP made more sense. In this talk, I will summarise the journey from porous InP that led to studies of other porous semiconductors such as silicon (3-10) and GaN (11-15), periodically ordered photonic crystal porous structures (16-26) and some optical, thermal and electrochemical properties photocatalysis, batteries and related that were modified by the porous structure, leading up to the most recent porous materials (27). References C. O’Dwyer, D. N. Buckley, D. Sutton, M. Serantoni and S. B. Newcomb, J. Electrochem. Soc., 154, H78 (2007). C. O’Dwyer, D. N. Buckley, D. Sutton and S. B. Newcomb, J. Electrochem. Soc., 153, G1039 (2006). C. O'Dwyer, W. McSweeney and G. Collins, ECS J. Solid State Sci. Technol., 5, R3059 (2016). W. McSweeney, C. Glynn, H. Geaney, G. Collins, J. D. Holmes and C. O'Dwyer, Semicond. Sci. Technol., 31, 014003 (2016). W. McSweeney, H. Geaney and C. O'Dwyer, Nano Res., 8, 1395 (2015). W. McSweeney, H. Geaney, C. Glynn, D. McNulty and C. O'Dwyer, ECS Trans., 66, 39 (2015). W. McSweeney, O. Lotty, C. Glynn, H. Geaney, J. D. Holmes and C. O'Dwyer, Electrochim. Acta, 135, 356 (2014). W. McSweeney, O. Lotty, N. V. V. Mogili, C. Glynn, H. Geaney, D. Tanner, J. D. Holmes and C. O'Dwyer, J. Appl. Phys., 114, 034309 (2013). E. Quiroga-González, J. Carstensen, C. Glynn, C. O’Dwyer and H. Föll, Phys. Chem. Chem. Phys., 16, 255 (2014). C. Glynn, K.-M. Jones, V. Mogili, W. McSweeney and C. O'Dwyer, ECS J. Solid State Sci. Technol., 6, N3029 (2017). O. V. Bilousov, J. J. Carvajal, A. Vilalta-Clemente, P. Ruterana, F. Díaz, M. Aguiló and C. O’Dwyer, Chem. Mater., 26, 1243−1249 (2014). O. V. Bilousov, J. J. Carvajal, H. Geaney, V. Z. Zubialevich, P. J. Parbrook, O. Martínez, J. Jiménez, F. Díaz, M. Aguiló and C. O’Dwyer, ACS Appl. Mater. Interface, 6, 17954 (2014). O. V. Bilousov, J. J. Carvajal, H. Geaney, F. Díaz, M. Aguiló and C. O’Dwyer, CrystEngComm, 16, 10255 (2014). O. V. Bilousov, H. Geaney, J. J. Carvajal, V. Z. Zubialevich, P. J. Parbrook, A. Giguère, D. Drouin, F. Díaz, M. Aguiló and C. O’Dwyer, Appl. Phys. Lett., 103, 112103 (2013). O. V. Bilousov, J. J. Carvajal, D. Drouin, X. Mateos, F. Díaz, M. Aguiló and C. O'Dwyer, ACS Appl. Mater. Interfaces, 4, 6927 (2012). S. O'Hanon, D. McNulty, R. Tian, J. Coleman and C. O'Dwyer, J. Electrochem. Soc., 167, 140532 (2020). D. McNulty, H. Geaney, Q. Ramasse and C. O'Dwyer, Adv. Funct. Mater., 30, 2005073 (2020). A. Lonergan, C. Hu and C. O'Dwyer, Phys. Rev. Materials, 4, 065201 (2020). G. Collins, A. Lonergan, D. McNulty, C. Glynn, D. Buckley, C. Hu and C. O’Dwyer, Adv. Mater. Interfaces, 7, 1901805 (2020). D. McNulty, A. Lonergan, S. O'Hanlon and C. O'Dwyer, Solid State Ionics, 314, 195 (2018). D. McNulty, H. Geaney, D. Buckley and C. O'Dwyer, Nano Energy, 43, 11 (2018). A. Lonergan, D. McNulty and C. O'Dwyer, J. Appl. Phys., 124, 095106 (2018). S. O'Hanlon, D. McNulty and C. O'Dwyer, J. Electrochem. Soc., 164, D111 (2017). D. McNulty, E. Carroll and C. O'Dwyer, Adv. Energy Mater., 7, 1602291 (2017). E. Armstrong and C. O'Dwyer, J. Mater. Chem. C, 3, 6109 (2015). E. Armstrong, D. McNulty, H. Geaney and C. O’Dwyer, ACS Appl. Mater. Interfaces, 7, 27006 (2015). A. Lonergan, B. Murphy and C. O'Dwyer, ECS J. Solid State Sci. Technol., 10, 085001 (2021). Figure 1. Bright field TEM of a cross section of an InP electrode after a potential sweep from 0.0 to 0.44 V (SCE) in 5 mol dm-3 KOH at 2.5 mV s-1. The plane of the micrograph is (011). Figure 1

In recent years, germanium (Ge) has attracted a lot of attention for the development of next generation devices due to its higher carrier mobilities compared with silicon (Si) and its compatibility for complementary metal-oxide-semiconductor (CMOS) applications. It is widely known that Ge is an indirect-band semiconductor like Si. However, by introducing tensile strain, the 136 meV difference between direct and indirect gaps can be reduced. Furthermore, in the case of 0.2-0.3% tensile strained Ge, n-type doping in the order of 1019 cm-3 were expected to be resulted in quasi direct-band light emission around 1550 nm wavelength. [1] The realization of this tensile strained n-Ge is promising for the integration of light sources on next generation Ge-based devices. Here, we focused on n-type Ge deposition using molecular beam epitaxy (MBE) method and have succeeded in realizing highly Sb-doped epitaxial n-Ge films by modulating the deposition temperatures. [2] Moreover, we have recently reported the crystallization of amorphous Ge by high-speed continuous wave laser annealing (CWLA), which more importantly also resulted in the introduction of 0.55-0.62% tensile strain. [3] In this study, we applied the similar annealing technique for crystallization of Sb-doped Ge toward the realization of tensile strained n-type Ge films. Sb-doped poly-crystalline Ge films with high Sb concentration (approximately 1019 cm-3) and thickness of about 100 nm were deposited on quartz substrate by molecular beam deposition at 450ºC substrate temperature. Then, 300 nm of SiO2 capping layer was deposited by sputtering in room temperature, such that the sample structure become that shown in Fig.1(a). The samples then annealed in the CWLA system equipped with Nd:YVO4 solid state laser with wavelength of 532 nm as the light source, which scan laser light at the speed (vscan) of 800 m/min. Also, the laser is focused to 20 μm diameter and shifted at 5 μm to scan the samples. Here, the laser power (Elaser) was changed from 300 to 1000 mW. After laser annealing, the capping layer were removed then the samples were characterized by micro-Raman spectroscopy. The annealed sample surface shows brighter contrast compared to the as-deposited samples, as shown in Fig.1(b) and (c), which indicate the structural change of Ge layer. Raman spectra measured at surface of annealed Ge layers are summarized in Fig.2. Here, Ge-Ge peak around 300.2 cm-1 confirmed on the samples, indicating the crystallization of the Ge layers. This peak is not shifted in low Elaser but largely shifted in high Elaser at up to -2.4 cm-1 for undoped and -3.6 cm-1 for the Sb-doped Ge films. This difference could be explained by the liquid phase recrystallization after Ge layer melted in high Elaser (≥600 mW). During recrystallization process, tensile strain is accumulated upon cooling as the tensile strain amount (0.43-0.63%) is agree with the thermal expansion value of Ge between solidification temperature and room temperature (-0.60%). This mechanism is similar to the crystallization of amorphous Ge films on quartz substrates in our previous work. [3] These results show the successful crystallization of tensile strained n-Ge layer by the CWLA method. This finding will be useful for the growth of Ge-based films and a promising step toward the development of CMOS-integrated optoelectronics. Further investigation of the annealing conditions and its relations with the properties of Sb-doped Ge films will be discussed in the main presentation. References Liu, J., Kimerling, L. C. & Michel, J. Semicond. Sci. Technol. 27, (2012). Saputro, R.H., Matsumura, R. & Fukata, N. Cryst. Growth & Des. 21, 6523–6528 (2021). Matsumura, R. & Fukata, N. ECS J. Solid State Sci. Technol. 9, 063002 (2020). Figure 1

In recent years, the physics community has experienced a revival of interest in spin effects in solid state systems. On one hand, solid state systems, particularly semicon- ductors and semiconductor nanosystems, allow one to perform benchtop studies of quantum and relativistic phenomena. On the other hand, interest is supported by the prospects of realizing spin-based electronics where the electron or nuclear spins can play a role of quantum or classical information carriers. This book aims at rather detailed presentation of multifaceted physics of interacting electron and nuclear spins in semiconductors and, particularly, in semiconductor-based low-dimensional structures. The hyperfine interaction of the charge carrier and nuclear spins increases in nanosystems compared with bulk materials due to localization of electrons and holes and results in the spin exchange between these two systems. It gives rise to beautiful and complex physics occurring in the manybody and nonlinear system of electrons and nuclei in semiconductor nanosystems. As a result, an understanding of the intertwined spin systems of electrons and nuclei is crucial for in-depth studying and control of spin phenomena in semiconductors. The book addresses a number of the most prominent effects taking place in semiconductor nanosystems including hyperfine interaction, nuclear magnetic resonance, dynamical nuclear polarization, spin-Faraday and -Kerr effects, processes of electron spin decoherence and relaxation, effects of electron spin precession mode-locking and frequency focusing, as well as fluctuations of electron and nuclear spins.

Detonation propulsion, both rocket-type and air-breathing, is currently a topical direction of research worldwide. Attention is mainly paid to various modes of operation of such engines, their stability, and reliability. As for the issues related to the initiation of the detonation process in such engines, they are usually not considered in detail. However, the initial stage of development of the operation process can be accompanied by a signi¦cant increase in the pressure acting on engine structural elements [1]. In the transition from research to prototypes, issues related to the weight of such engines and their thrust-to-weight ratio will come to the fore. To ensure a minimum margin of safety in engine design, it is required to organize mild rather than strong initiation of operation process excluding the possibility of severe explosions of large volumes of fuel mixture inside the engine or in its close vicinity. This work dealt with experimental simulation of ignition, §ame acceleration, and de§agration-to-detonation transition (DDT) in a semicon¦ned layer of explosive mixture in a slot representing the unrolled annular combustor of a rotating detonation engine. The test mixture was represented by nonpremixed ethylene oxygen mixture of overall stoichiometric composition.