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181.
The Kohler slope of the linear magnetoresistance of potassium films measured in the Sondheimer geometry at 4.2 K depends on , the ratio of the film thickness to electron mean free path. The maximum value with a value of 0.1 occurs at =1. Calculations show that the slope decreases slowly from the maximum for smaller and larger values of . The slope is greater than 10–3 for between 0.035 and 100. The dependence of the Kohler slope on the residual resistance ratio of annealed samples measured by Taub et al. is attributed to the dependence. The results show that samples of centimeter thickness are required to reduce significantly the size-dependent Kohler slope, and the slope must be shown to be independent of the sample thickness for the study of intrinsic effects. 相似文献
182.
Leonard M. Hanssen Sergey N. Mekhontsev Vladimir B. Khromchenko 《International Journal of Thermophysics》2010,31(10):1972-1978
A comparison of the spectral directional emittance of samples as a function of wavelength was performed at the Fourier Transform
Infrared Spectrophotometry (FTIS) and the Advanced Infrared Radiometry and Imaging (AIRI) facilities at NIST. At the FTIS,
the emittance is obtained indirectly through the measurement of near-normal directional-hemispherical reflectance (DHR) using
an infrared integrating sphere. At the AIRI, the normal directional emittance is obtained directly through the measurement
of the sample spectral radiance referenced to that from blackbody sources, while the sample is located behind a black plate
of known temperature and emittance. On the same setup at the AIRI, the normal emittance at near ambient temperatures is also
measured indirectly by a “two-temperature” method in which the sample spectral radiance is measured while the background temperature
is controlled and varied. The sample emittance measurements on the comparison samples are presented over a wavelength range
of 3.4 μm to 13.5 μm at several near-ambient temperatures and for near-normal incidence. The results obtained validate the
two independent capabilities and demonstrate the potential of the controlled background methods for measurements of the radiative
properties of IR materials. 相似文献
183.
Béatrice Fuster Deborah Houssin-Agbomson Simon Jallais Elena Vyazmina Guy Dang-Nhu Gilles Bernard-Michel Mike Kuznetsov Vladimir Molkov Boris Chernyavskiy Volodymyr Shentsov Dmitry Makarov Randy Dey Philip Hooker Daniele Baraldi Evelyn Weidner Daniele Melideo Valerio Palmisano Alexandros Venetsanos Jan Der Kinderen 《International Journal of Hydrogen Energy》2017,42(11):7600-7607
Hydrogen energy applications often require that systems are used indoors (e.g., industrial trucks for materials handling in a warehouse facility, fuel cells located in a room, or hydrogen stored and distributed from a gas cabinet). It may also be necessary or desirable to locate some hydrogen system components/equipment inside indoor or outdoor enclosures for security or safety reasons, to isolate them from the end-user and the public, or from weather conditions.Using of hydrogen in confined environments requires detailed assessments of hazards and associated risks, including potential risk prevention and mitigation features. The release of hydrogen can potentially lead to the accumulation of hydrogen and the formation of a flammable hydrogen-air mixture, or can result in jet-fires. Within Hyindoor European Project, carried out for the EU Fuel Cells and Hydrogen Joint Undertaking safety design guidelines and engineering tools have been developed to prevent and mitigate hazardous consequences of hydrogen release in confined environments. Three main areas are considered: Hydrogen release conditions and accumulation, vented deflagrations, jet fires and including under-ventilated flame regimes (e.g., extinguishment or oscillating flames and steady burns). Potential RCS recommendations are also identified. 相似文献
184.
185.
186.
187.
Ivan Rehor Jitka Slegerova Jan Kucka Vladimir Proks Vladimira Petrakova Marie‐Pierre Adam François Treussart Stuart Turner Sara Bals Pavel Sacha Miroslav Ledvina Amy M. Wen Nicole F. Steinmetz Petr Cigler 《Small (Weinheim an der Bergstrasse, Germany)》2014,10(6):1106-1115
High pressure high temperature (HPHT) nanodiamonds (NDs) represent extremely promising materials for construction of fluorescent nanoprobes and nanosensors. However, some properties of bare NDs limit their direct use in these applications: they precipitate in biological solutions, only a limited set of bio‐orthogonal conjugation techniques is available and the accessible material is greatly polydisperse in shape. In this work, we encapsulate bright 30‐nm fluorescent nanodiamonds (FNDs) in 10–20‐nm thick translucent (i.e., not altering FND fluorescence) silica shells, yielding monodisperse near‐spherical particles of mean diameter 66 nm. High yield modification of the shells with PEG chains stabilizes the particles in ionic solutions, making them applicable in biological environments. We further modify the opposite ends of PEG chains with fluorescent dyes or vectoring peptide using click chemistry. High conversion of this bio‐orthogonal coupling yielded circa 2000 dye or peptide molecules on a single FND. We demonstrate the superior properties of these particles by in vitro interaction with human prostate cancer cells: while bare nanodiamonds strongly aggregate in the buffer and adsorb onto the cell membrane, the shell encapsulated NDs do not adsorb nonspecifically and they penetrate inside the cells. 相似文献
188.
This paper studies the behavior of motions of large-scale (LS) semistate systems (SSS) governed byP
i
(t)x
i
=M
i
(t,x
i
)x
i
+f
i
(t)+h
i
(t, x), i=1,2,...,s, =(x
1
T
x
2
T
x
s
T
)T, where matricesP
i
(t) are singular. Using Lyapunov's approach and the tools for LS system analysis, a variant of attractivity and ultimate boundedness of appropriate time-variable sets are investigated. The results are based on a specific choice of the aggregate functions. It is assumed that the reduction of equations to a normal form of lower order is inconvenient. The aggregation-decomposition approach used in this paper reduces the dimensionality of an aggregate matrix of the system to the number of its systems. Motion properties of LS systems are deduced from the properties of its isolated subsystems, the character of interconnections, and the conditions imposed on the system aggregate matrix. Sufficient algebraic conditions for the above-mentioned motion properties are developed. 相似文献
189.
Xin Shi Julian Key Shan Ji Vladimir Linkov Fusheng Liu Hui Wang Hengjun Gai Rongfang Wang 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(29)
Porous Ni(OH)2 nanoflakes are directly grown on the surface of nickel foam supported Ni3Se2 nanowire arrays using an in situ growth procedure to form 3D Ni3Se2@Ni(OH)2 hybrid material. Owing to good conductivity of Ni3Se2, high specific capacitance of Ni(OH)2 and its unique architecture, the obtained Ni3Se2@Ni(OH)2 exhibits a high specific capacitance of 1689 µAh cm?2 (281.5 mAh g?1) at a discharge current of 3 mA cm?2 and a superior rate capability. Both the high energy density of 59.47 Wh kg?1 at a power density of 100.54 W kg?1 and remarkable cycling stability with only a 16.4% capacity loss after 10 000 cycles are demonstrated in an asymmetric supercapacitor cell comprising Ni3Se2@Ni(OH)2 as a positive electrode and activated carbon as a negative electrode. Furthermore, the cell achieved a high energy density of 50.9 Wh L?1 at a power density of 83.62 W L?1 in combination with an extraordinary coulombic efficiency of 97% and an energy efficiency of 88.36% at 5 mA cm?2 when activated carbon is replaced by metal hydride from a commercial NiMH battery. Excellent electrochemical performance indicates that Ni3Se2@Ni(OH)2 composite can become a promising electrode material for energy storage applications. 相似文献
190.
Vladimir Pankov Dongyi Seo Sunghun Lee Eungsun Byon 《Materials Science & Technology》2020,36(5):564-574
ABSTRACTSpitting behaviour of four casted and powder metallurgy ingots used in the fabrication of NiCoCrAlY-type environmental protective coatings by electron beam physical vapour deposition was investigated and correlated with ingot microstructures and compositions. Spits found in the coatings mainly consisted of the Ni5Y phase precipitated in the β-NiAl matrix while their typical size exceeded 50?µm. Spitting was less pronounced for ingots having a higher Cr content, larger size of γ-Ni(Co, Cr) precipitates formed within β-NiAl grains and narrower transitional zone formed at the interface between molten and unmolten ingot regions and consisting of coarsened β grains. Large (above 100?µm) agglomerates of the Ni5Y phase detected below the zone were identified as the main spit precursors. 相似文献