Similarities and Differences Between Silicon and Carbon Nanostructures: Theoretical Predictions

Author(s):  
Aristides D. Zdetsis ◽  
George Maroulis ◽  
Theodore E. Simos
Author(s):  
Cisco Gooding

We analyse the behaviour of acoustic vortex beams interacting with rotating, fluid-saturated porous materials. Regions of the parameter space that exhibit distinct dynamical features are identified, with a focus on features that are relevant to the characterization of rotational superradiance. We discuss the similarities and differences between two recent proposals to observe acoustic superradiance with rotating, air-saturated sound absorbers. Finally, theoretical predictions for macroscopic acoustic scattering, obtained by averaging over interactions between the fluid and the porous material at the microscopic level, are compared with predictions of the first-Born approximation. This article is part of a discussion meeting issue ‘The next generation of analogue gravity experiments’.


2021 ◽  
Vol 7 (1) ◽  
pp. 17
Author(s):  
Leonid A. Chernozatonskii ◽  
Victor A. Demin ◽  
Dmitry G. Kvashnin

Diamanes are 2D diamond-like films that are nanometers in thickness. Diamanes can exist as bilayer or multilayer graphene with various modes of stacking and interlayer covalent sp3 bonds. The term “diamane” is used broadly for a variety of diamond-like materials at the nanoscale, from individual diamond clusters to nanocrystal films. A short overview of recent progress in the investigation of diamanes, starting from the first theoretical predictions to practical realization, is presented. The results of both theoretical and experimental studies on diamanes with various atomic structures and types of functionalization are considered. It is shown that diamanes are stronger than graphene and graphane and have wide bandgaps ranging from 3.1 to 4.5 eV depending on the structure. Diamane-like structures have been obtained using different experimental techniques, and their structures have been determined by Raman spectroscopy. The potential applications of these carbon nanostructures are briefly reviewed.


1988 ◽  
Vol 102 ◽  
pp. 41
Author(s):  
E. Silver ◽  
C. Hailey ◽  
S. Labov ◽  
N. Madden ◽  
D. Landis ◽  
...  

The merits of microcalorimetry below 1°K for high resolution spectroscopy has become widely recognized on theoretical grounds. By combining the high efficiency, broadband spectral sensitivity of traditional photoelectric detectors with the high resolution capabilities characteristic of dispersive spectrometers, the microcalorimeter could potentially revolutionize spectroscopic measurements of astrophysical and laboratory plasmas. In actuality, however, the performance of prototype instruments has fallen short of theoretical predictions and practical detectors are still unavailable for use as laboratory and space-based instruments. These issues are currently being addressed by the new collaborative initiative between LLNL, LBL, U.C.I., U.C.B., and U.C.D.. Microcalorimeters of various types are being developed and tested at temperatures of 1.4, 0.3, and 0.1°K. These include monolithic devices made from NTD Germanium and composite configurations using sapphire substrates with temperature sensors fabricated from NTD Germanium, evaporative films of Germanium-Gold alloy, or material with superconducting transition edges. A new approache to low noise pulse counting electronics has been developed that allows the ultimate speed of the device to be determined solely by the detector thermal response and geometry. Our laboratory studies of the thermal and resistive properties of these and other candidate materials should enable us to characterize the pulse shape and subsequently predict the ultimate performance. We are building a compact adiabatic demagnetization refrigerator for conveniently reaching 0.1°K in the laboratory and for use in future satellite-borne missions. A description of this instrument together with results from our most recent experiments will be presented.


Author(s):  
A.C. Daykin ◽  
C.J. Kiely ◽  
R.C. Pond ◽  
J.L. Batstone

When CoSi2 is grown onto a Si(111) surface it can form in two distinct orientations. A-type CoSi2 has the same orientation as the Si substrate and B-type is rotated by 180° degrees about the [111] surface normal.One method of producing epitaxial CoSi2 is to deposit Co at room temperature and anneal to 650°C.If greater than 10Å of Co is deposited then both A and B-type CoSi2 form via a number of intermediate silicides .The literature suggests that the co-existence of A and B-type CoSi2 is in some way linked to these intermediate silicides analogous to the NiSi2/Si(111) system. The phase which forms prior to complete CoSi2 formation is CoSi. This paper is a crystallographic analysis of the CoSi2/Si(l11) bicrystal using a theoretical method developed by Pond. Transmission electron microscopy (TEM) has been used to verify the theoretical predictions and to characterise the defect structure at the interface.


1973 ◽  
Vol 16 (2) ◽  
pp. 257-266 ◽  
Author(s):  
Milo E. Bishop ◽  
Robert L. Ringel ◽  
Arthur S. House

The oral form-discrimination abilities of 18 orally educated and oriented deaf high school subjects were determined and compared to those of manually educated and oriented deaf subjects and normal-hearing subjects. The similarities and differences among the responses of the three groups were discussed and then compared to responses elicited from subjects with functional disorders of articulation. In general, the discrimination scores separated the manual deaf from the other two groups, particularly when differences in form shapes were involved in the test. The implications of the results for theories relating orosensory-discrimination abilities are discussed. It is postulated that, while a failure in oroperceptual functioning may lead to disorders of articulation, a failure to use the oral mechanism for speech activities, even in persons with normal orosensory capabilities, may result in poor performance on oroperceptual tasks.


2016 ◽  
Vol 21 (3) ◽  
pp. 206-217 ◽  
Author(s):  
Verónica Sevillano ◽  
Susan T. Fiske

Abstract. Nonhuman animals are typically excluded from the scope of social psychology. This article presents animals as social objects – targets of human social responses – overviewing the similarities and differences with human targets. The focus here is on perceiving animal species as social groups. Reflecting the two fundamental dimensions of humans’ social cognition – perceived warmth (benign or ill intent) and competence (high or low ability), proposed within the Stereotype Content Model ( Fiske, Cuddy, Glick, & Xu, 2002 ) – animal stereotypes are identified, together with associated prejudices and behavioral tendencies. In line with human intergroup threats, both realistic and symbolic threats associated with animals are reviewed. As a whole, animals appear to be social perception targets within the human sphere of influence and a valid topic for research.


2020 ◽  
Vol 51 (5) ◽  
pp. 354-359 ◽  
Author(s):  
Yavor Paunov ◽  
Michaela Wänke ◽  
Tobias Vogel

Abstract. Combining the strengths of defaults and transparency information is a potentially powerful way to induce policy compliance. Despite negative theoretical predictions, a recent line of research revealed that default nudges may become more effective if people are informed why they should exhibit the targeted behavior. Yet, it is an open empirical question whether the increase in compliance came from setting a default and consequently disclosing it, or the provided information was sufficient to deliver the effect on its own. Results from an online experiment indicate that both defaulting and transparency information exert a statistically independent effect on compliance, with highest compliance rates observed in the combined condition. Practical and theoretical implications are discussed.


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