A high-performance eletromagnetic wave absorption material based on biochar derived from pomelo peel

2021 ◽  
pp. 1-10
Author(s):  
Yu Ping CAI
Keyword(s):  
Reflection Loss ◽  
Renewable Resources ◽  
Mass Fraction ◽  
High Performance ◽  
High Vacuum ◽  
Small Ring ◽  
Biomass Carbon ◽  
Wave Absorption ◽  
Pomelo Peel ◽  
Maximum Reflection Loss

As a kind of renewable resources with abundant reserves, research on the utilization of biochar has been paid more and more attention. However, the use of pomelo peel biomass carbon in the field of eletromagnetic wave absorption (EWA) has never been reported. In this study, the pomelo peel of natural recovery were carbonized at temperature of 700°C for 1 h in a high vacuum of 300 pa. The as-prepared biomass carbon were uniformly mixed with the paraffin by heat-assisted impregnation to prepare small ring-shaped devices, and the EWA characteristics of the small devices were investigated. The absorbing measurements were performed with the filling mass fraction of 30% and 50% of the biochar, respectively. The biochar with a mass fraction of 50% showed the excellent absorbing properties with the maximum reflection loss up to –44.3 dB at 9.84 GHz in the thickness of 2.0 mm, which is expected to be used as light, broadband and efficient EWA material.

Electromagnetic Properties of Nanometer SiC/CNTs Composite

2009 ◽  
Vol 79-82 ◽  
pp. 349-352 ◽  
Author(s):  
Jian Xun Yao ◽  
Liu Ying Wang ◽  
Gu Liu ◽  
Shao Chun Hua
Keyword(s):  
Microwave Absorption ◽  
Reflection Loss ◽  
Complex Permittivity ◽  
Mass Fraction ◽  
Low Frequency ◽  
Electromagnetic Properties ◽  
Transmission Line Theory ◽  
Microwave Absorption Properties ◽  
Line Theory ◽  
Maximum Reflection Loss

Both the complex permittivity and permeability of nanometer SiC and nanometer SiC/CNTs composite were investigated by Hewlett-Packard 8510B Network Analyzer. The results show that the complex permittivity of nanometer SiC/CNTs composite is much higher than that of nanometer SiC. Reflection curves of nanometer SiC and nanometer SiC/CNTs composite calculated with electromagnetic wave transmission-line theory show that the addition of CNTs at 6 wt%, 12 wt% and 18 wt% in nanometer SiC absorber can improve its microwave absorption properties strongly. There is a relationship between the mass fraction of CNTs and microwave absorption ability. With increase of the mass fraction of CNTs, its microwave absorption ability firstly increased then decreased. From the simulation, it was found that nanometer SiC with 12 wt% CNTs gave the optimum microwave absorption. The corresponding frequency of maximum reflection loss value of nanometer SiC/CNTs composite gradually moves to the low frequency range with increase of thickness. The maximum reflection loss value of nanometer SiC/CNTs composite (CNTs content is 12 wt%) was -25.74dB at the corresponding frequency of 11.60 GHz with a bandwidth under -5 dB (68% absorption) is 7.16 GHz when the thickness is 2.0 mm.

Design and Optimize Spherical Particle Absorber for Broadband Electromagnetic Wave Absorption Wall

2010 ◽  
Vol 143-144 ◽  
pp. 1051-1055
Author(s):  
Zhang Hong Tang ◽  
Wang Qun
Keyword(s):  
Electromagnetic Wave ◽  
Spherical Particle ◽  
Reflection Loss ◽  
Electromagnetic Wave Absorption ◽  
Wave Absorption ◽  
Simulation Results ◽  
Maximum Reflection Loss

In this paper, a method to simulate the absorbing effectiveness of spherical particle absorber is presented and the effect of the diameter of spheres, the number of layer and the stack modes of sphere particle to the absorbing effectiveness were also researched. Basing on the simulation results, an optimal spherical particle absorber was designed. The absorber has 3 layers with 1 mm, 2 mm and 4 mm spheres stacked on each layer respectively. Simulation result shows that the optimal absorber achieves a maximum reflection loss of -15 dB and the bandwidth being lower than -5 dB is more than 16 GHz in 1~18 GHz.

Vacuum System to Minimize the Specimen Contamination of High-Performance EM

1977 ◽  
Vol 35 ◽  
pp. 68-69
Author(s):  
N. Yoshimura ◽  
K. Shirota ◽  
T. Etoh
Keyword(s):  
Electron Microscope ◽  
High Speed ◽  
High Performance ◽  
High Vacuum ◽  
Vacuum System ◽  
Pump System ◽  
Pumping System ◽  
Diffusion Pump ◽  
Almost All ◽  
Cascade Type

One of the most important requirements for a high-performance EM, especially an analytical EM using a fine beam probe, is to prevent specimen contamination by providing a clean high vacuum in the vicinity of the specimen. However, in almost all commercial EMs, the pressure in the vicinity of the specimen under observation is usually more than ten times higher than the pressure measured at the punping line. The EM column inevitably requires the use of greased Viton O-rings for fine movement, and specimens and films need to be exchanged frequently and several attachments may also be exchanged. For these reasons, a high speed pumping system, as well as a clean vacuum system, is now required. A newly developed electron microscope, the JEM-100CX features clean high vacuum in the vicinity of the specimen, realized by the use of a CASCADE type diffusion pump system which has been essentially improved over its predeces- sorD employed on the JEM-100C.

scholarly journals Development and certification of a reference material for zearalenone in maize germ oil

2021 ◽  
Author(s):  
Juliane Riedel ◽  
Sebastian Recknagel ◽  
Diana Sassenroth ◽  
Tatjana Mauch ◽  
Sabine Buttler ◽  
...  
Keyword(s):  
Reference Material ◽  
Reference Materials ◽  
Mass Fraction ◽  
High Performance ◽  
Certified Reference Materials ◽  
Maximum Level ◽  
Whole Process ◽  
Commission Regulation ◽  
Maize Oil ◽  
Maize Germ

AbstractZearalenone (ZEN), an estrogenic mycotoxin produced by several species of Fusarium fungi, is a common contaminant of cereal-based food worldwide. Due to frequent occurrences associated with high levels of ZEN, maize oil is a particular source of exposure. Although a European maximum level for ZEN in maize oil exists according to Commission Regulation (EC) No. 1126/2007 along with a newly developed international standard method for analysis, certified reference materials (CRM) are still not available. To overcome this lack, the first CRM for the determination of ZEN in contaminated maize germ oil (ERM®-BC715) was developed in the frame of a European Reference Materials (ERM®) project according to the requirements of ISO Guide 35. The whole process of CRM development including preparation, homogeneity and stability studies, and value assignment is presented. The assignment of the certified mass fraction was based upon an in-house study using high-performance liquid chromatography isotope dilution tandem mass spectrometry. Simultaneously, to support the in-house certification study, an interlaboratory comparison study was conducted with 13 expert laboratories using different analytical methods. The certified mass fraction and expanded uncertainty (k = 2) of ERM®-BC715 (362 ± 22) μg kg−1 ZEN are traceable to the SI. This reference material is intended for analytical quality control and contributes to the improvement of consumer protection and food safety. Graphical abstract

Co3O4 anchored on meshy biomass carbon derived from kelp for high‐performance ultracapacitor electrode

2021 ◽  
Vol 266 ◽  
pp. 124556
Author(s):  
Ruyi Zou ◽  
Lin Zhu ◽  
Lijun Yan ◽  
Bo Shao ◽  
Hui Cheng ◽  
...  
Keyword(s):  
High Performance ◽  
Biomass Carbon

Semi-bio-based aromatic polyamides from 2,5-furandicarboxylic acid: toward high-performance polymers from renewable resources

RSC Advances ◽  
2016 ◽  
Vol 6 (90) ◽  
pp. 87013-87020 ◽  
Author(s):  
Kaiju Luo ◽  
Yan Wang ◽  
Junrong Yu ◽  
Jing Zhu ◽  
Zuming Hu
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Renewable Resources ◽  
High Performance ◽  
Good Thermal Stability ◽  
Aromatic Polyamides ◽  
High Performance Polymers ◽  
Furandicarboxylic Acid

Aromatic furanic polyamides with relatively high molecular weight were synthesized, and good thermal stability and mechanical properties were demonstrated.

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