Carbonized Silk Fiber Mat: a Flexible and Broadband Microwave Absorber, and the Length Effect

2021 ◽  
Vol 9 (38) ◽  
pp. 12747-12754
Author(s):  
Yi Hou ◽  
Jing Quan ◽  
Xinran Su ◽  
Chaoran Deng ◽  
Yong Yang ◽  
...  
Keyword(s):  
Microwave Absorber ◽  
Silk Fiber ◽  
Length Effect

The Effect of Path Length and Display Size on Memory for Spatial Information

2012 ◽  
Vol 59 (3) ◽  
pp. 147-152 ◽  
Author(s):  
Katherine Guérard ◽  
Sébastien Tremblay
Keyword(s):  
Path Length ◽  
Potential Role ◽  
Spatial Information ◽  
Recall Performance ◽  
Minor Role ◽  
Length Effect ◽  
Serial Memory ◽  
Fixed Reference ◽  
A Minor

In serial memory for spatial information, some studies showed that recall performance suffers when the distance between successive locations increases relatively to the size of the display in which they are presented (the path length effect; e.g., Parmentier et al., 2005) but not when distance is increased by enlarging the size of the display (e.g., Smyth & Scholey, 1994). In the present study, we examined the effect of varying the absolute and relative distance between to-be-remembered items on memory for spatial information. We manipulated path length using small (15″) and large (64″) screens within the same design. In two experiments, we showed that distance was disruptive mainly when it is varied relatively to a fixed reference frame, though increasing the size of the display also had a small deleterious effect on recall. The insertion of a retention interval did not influence these effects, suggesting that rehearsal plays a minor role in mediating the effects of distance on serial spatial memory. We discuss the potential role of perceptual organization in light of the pattern of results.

The list-length effect occurs in cued recall with the retroactive design but not the proactive design.

2020 ◽  
Vol 74 (1) ◽  
pp. 12-24 ◽  
Author(s):  
Tyler M. Ensor ◽  
Dominic Guitard ◽  
Tamra J. Bireta ◽  
William E. Hockley ◽  
Aimée M. Surprenant
Keyword(s):  
List Length ◽  
Cued Recall ◽  
Length Effect ◽  
List Length Effect

Nanocomposite Graphene based Tunable Absorber for Combating Electromagnetic Pollution

2019 ◽  
Vol 15 ◽  
Author(s):  
Surekha Rani ◽  
Anupma Marwaha ◽  
Sanjay Marwaha
Keyword(s):  
Reflection Coefficient ◽  
Traffic Congestion ◽  
Microwave Absorber ◽  
Electromagnetic Properties ◽  
Electric Conductor ◽  
High Frequency Structure Simulator ◽  
Bias Potential ◽  
External Bias ◽  
Tunable Microwave ◽  
Tunable Absorber

Background: Advancement in wireless communication technology has raised today’s living standards but consequently leads to the problems of electromagnetic (EM) air pollution as well as spectrum congestion particularly in radio frequency band. To overcome traffic congestion problem in lower bands, terahertz frequency bands are explored but EM pollution still persists as global issue which can be addressed by a tunable microwave absorber. At THz frequencies, 2-D nanostructured graphene has been observed to be less lossy than using other materials and further finds its most interesting applications on account of the plasmonic mode supported by graphene resulting in extreme device miniaturization. At micro and mm-waves graphene is resistive hence can be electronically controlled, ensuring its suitability for the design of tunable microwave absorber. Objective: Designing of a frequency reconfigurable or frequency tunable absorber is the prime objective of current work. Two-dimensional graphene absorber has been proposed here having inherent bandgap tunability property which means the electromagnetic properties of graphene can be controlled via varying external bias potential. Methods: The numerical modelling of graphene microwave absorber utilizing bulk graphene backed by glass and perfect electric conductor layer is reported in this paper. Finite element Method (FEM) based high frequency structure simulator (HFSS) platform is used to simulate the graphene absorber model. The whole structure is placed into a rectangular waveguide with two ports for absorber excitation. Results: The variation of electromagnetic properties of graphene absorber is achieved by changing bias potential and further the absorption tunability for the designed absorber is investigated in the range from 2 GHz to 18 GHz. From reflection coefficient curves, it is authenticated that -72.6 dB reflection coefficient dip has been obtained at 14 GHz for 5 volt bias potential which shifts to higher side of frequency as the potential changes from 5 volts to 25 volts. Conclusion: The results show that by increasing bias potential, absorption coefficient shifts to higher frequency and proves to be a tunable wideband absorber whose resonant frequency can changed from one value to another without changing thickness or material properties of absorber thus can effectively incorporate with antenna substrate or surface of radar.

scholarly journals Development and performance study of a natural silk fiber facial mask paper

2020 ◽  
Vol 15 ◽  
pp. 155892502097575
Author(s):  
Huiling Wang ◽  
Bin Zhou
Keyword(s):  
Silk Fiber ◽  
Entrainment Rate ◽  
Performance Study ◽  
Wet Strength ◽  
Facial Mask ◽  
Antibacterial Performance ◽  
Lower Elongation ◽  
The Common ◽  
And Performance ◽  
Acid Structure

Facial masks are beauty products which composed of a facial mask paper and beauty solution. Silk contains the amino acid structure closest to the human skin, and has the skin-friendly, cosmetic and antibacterial functions, but the common method for making nonwoven facial mask paper is not suitable for silk. In this paper, the silkworm’s spinning path is intervened manually to obtain a smart silk facial mask paper (SMC) of controllable thickness, so that the sericin on the silk fiber is well preserved. In the experiment where the SMC is compared with the nonwoven 384-cuprammonium rayon facial mask paper (CRMC) which is the most widely used in the market, it is found that the ways of forming the two facial mask paper are completely different, and therefore the morphologies under SEM are obviously different. The thickness of the SMC is 0.183 mm and the areal weight of it is 38.0 g/m2. It is very close to the CRMC (0.187 mm, 38.4 g/m2). The porosity of the SMC is 84.0%, which is slightly lower than that of the CRMC (86.3%), but its pores are well distributed. Compared with the CRMC, the smart SMC has higher dry and wet strength, lower elongation, slightly lower air permeability and liquid entrainment rate, and better antibacterial performance.

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