Cutoff Wave Number for Shear Waves in a Two-Dimensional Yukawa System (Dusty Plasma)

2006 ◽  
Vol 97 (11) ◽  
Author(s):  
V. Nosenko ◽  
J. Goree ◽  
A. Piel
1998 ◽  
Vol 4 (2) ◽  
pp. 73-90 ◽  
Author(s):  
Peter Vadasz ◽  
Saneshan Govender

The stability and onset of two-dimensional convection in a rotating fluid saturated porous layer subject to gravity and centrifugal body forces is investigated analytically. The problem corresponding to a layer placed far away from the centre of rotation was identified as a distinct case and therefore justifying special attention. The stability of a basic gravity driven convection is analysed. The marginal stability criterion is established in terms of a critical centrifugal Rayleigh number and a critical wave number for different values of the gravity related Rayleigh number. For any given value of the gravity related Rayleigh number there is a transitional value of the wave number, beyond which the basic gravity driven flow is stable. The results provide the stability map for a wide range of values of the gravity related Rayleigh number, as well as the corresponding flow and temperature fields.


2021 ◽  
Vol 2114 (1) ◽  
pp. 012084
Author(s):  
Hammad R. Humud ◽  
Fatimah Jumaah Moaen

Abstract The current study examines recent advancements in surface-enhanced Raman scattering (SERS), a technique that employs flexible surfaces as an active substrate, this surfaces consist from two-dimensional thermo-plasmonic grating. With 53 nm Au layer (was deposited on the 2D grating structure of the PDMS by the PVD method). The explosive wire technique was used to preparing Ag nanoparticles that were used for the purpose of SERS. The effect of the plasmonic nanostructures on the absorption spectra and Surface - Enhanced Raman Scattering (SERS) activities was examined. Rhodamine 6G dye was used as a probe molecule. X-Ray diffraction (XRD) was used to examine the structural characteristics of the nanoparticles. The morphology was assessed using Field Emission Scanning Electron Microscopy(FESEM). A twin beam UV-Vis Spectrophotometer was used to measure the absorption of the combined Rh6G dye (concentration 1×10“–6M) with the nanostructures. a Sunshine Raman microscope system and a 50mm objective lens, used for investigating the Raman spectra of the Rh6G combined with nanostructures. The results showed that the enhancement factor (EF) for SERS of R6G (1×M) reached to (2.2×10 3) When using Ag nanoparticles and (0.08 × 103) when R6G deposited directly on the flexible substrates without nanostructures at the wave number (1650 cm−1), we produced a recyclable, homogeneous, and highly sensitive SERS substrate with dependable reproducibility. For the SERS substrate, a surface made up of two-dimensional (2D) flexible grating substrates was chosen to provide multiple modalities in electrical and medicinal applications.


2021 ◽  
Vol 118 (3) ◽  
pp. e2016862118
Author(s):  
Duyu Chen ◽  
Yu Zheng ◽  
Lei Liu ◽  
Ge Zhang ◽  
Mohan Chen ◽  
...  

Disordered hyperuniformity (DHU) is a recently discovered novel state of many-body systems that possesses vanishing normalized infinite-wavelength density fluctuations similar to a perfect crystal and an amorphous structure like a liquid or glass. Here, we discover a hyperuniformity-preserving topological transformation in two-dimensional (2D) network structures that involves continuous introduction of Stone–Wales (SW) defects. Specifically, the static structure factor S(k) of the resulting defected networks possesses the scaling S(k)∼kα for small wave number k, where 1≤α(p)≤2 monotonically decreases as the SW defect concentration p increases, reaches α≈1 at p≈0.12, and remains almost flat beyond this p. Our findings have important implications for amorphous 2D materials since the SW defects are well known to capture the salient feature of disorder in these materials. Verified by recently synthesized single-layer amorphous graphene, our network models reveal unique electronic transport mechanisms and mechanical behaviors associated with distinct classes of disorder in 2D materials.


2005 ◽  
Vol 38 (13) ◽  
pp. 3057-3063 ◽  
Author(s):  
Songfen Liu ◽  
Xin Wang ◽  
Beilai Hu ◽  
Long Wang ◽  
Yanhong Liu
Keyword(s):  

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