scholarly journals Facile Synthesis of Sandwich-Like rGO/CuS/Polypyrrole Nanoarchitectures for Efficient Electromagnetic Absorption

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 446
Author(s):  
Bing Zhang ◽  
Shaofeng Lin ◽  
Jingjing Zhang ◽  
Xiaopeng Li ◽  
Xiaodong Sun
Keyword(s):  
Electromagnetic Waves ◽  
Experimental Result ◽  
Effective Bandwidth ◽  
Human Beings ◽  
Step Method ◽  
Electromagnetic Absorption ◽  
Reduced Graphene ◽  
Electromagnetic Pollution ◽  
Harmful Effects ◽  
Minimum Reflection Loss

Currently, electromagnetic pollution management has gained much attention due to the various harmful effects on wildlife and human beings. Electromagnetic absorbers can convert energy from electromagnetic waves into thermal energy. Previous reports have demonstrated that reduced graphene oxide (rGO) makes progress in the electromagnetic absorption (EA) field. But the high value of permittivity of rGO always mismatches the impedance which results in more electromagnetic wave reflection on the surface. In this work, sandwich-like rGO/CuS/polypyrrole (PPy) nanoarchitectures have been synthesized by a facile two-step method. The experimental result has shown that a paraffin composite containing 10 wt.% of rGO/CuS/PPy could achieve an enhanced EA performance both in bandwidth and intensity. The minimum reflection loss (RL) value of −49.11 dB can be reached. Furthermore, the effective bandwidth can cover 4.88 GHz. The result shows that the as-prepared rGO/CuS/PPy nanoarchitectures will be a promising EA material.

scholarly journals NiS2@MoS2 Nanospheres Anchored on Reduced Graphene Oxide: A Novel Ternary Heterostructure with Enhanced Electromagnetic Absorption Property

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 292 ◽  
Author(s):  
Zhi Zhang ◽  
Xuliang Lv ◽  
Yiwang Chen ◽  
Pin Zhang ◽  
Mingxu Sui ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Impedance Matching ◽  
Interfacial Polarization ◽  
Effective Bandwidth ◽  
Military Equipment ◽  
Electromagnetic Absorption ◽  
Reduced Graphene ◽  
Absorption Performance ◽  
Minimum Reflection Loss

For the purposes of strength, military equipment camouflage, and protecting the health of organisms, electromagnetic wave absorbing materials have received a lot of attention and are widely studied. In addition to having a strong absorption intensity and a wide effective absorption bandwidth, materials that are lightweight, thermally stable, and antioxidative are also highly desirable. In this study, we fabricated core–shell structured NiS2@MoS2 nanospheres anchored on reduced graphene oxide (rGO) nanosheets (NiS2@MoS2/rGO) by a simple two-step hydrothermal method. The combination ratio was adjusted to achieve proper impedance matching. The electromagnetic parameters and the absorption performance were investigated in detail. A composite loaded with 30 wt.% of the sample achieved a minimum reflection loss (RL) value of −29.75 dB and the effective bandwidth (RL value of less than −10 dB) ranged from 4.95 GHz to 18.00 GHz (13.05 GHz), with a thickness ranging from 1.5 mm to 4.0 mm. This study proved that the generated significant interfacial polarization and synergetic interaction between components can result in NiS2@MoS2/rGO composites with enhanced electromagnetic absorption performance.

scholarly journals Superparamagnetic ZnFe2O4 Nanoparticles-Reduced Graphene Oxide-Polyurethane Resin Based Nanocomposites for Electromagnetic Interference Shielding Application

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1112
Author(s):  
Raghvendra Singh Yadav ◽  
Anju ◽  
Thaiskang Jamatia ◽  
Ivo Kuřitka ◽  
Jarmila Vilčáková ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Electromagnetic Waves ◽  
Spinel Ferrite ◽  
Ferrite Nanoparticles ◽  
Resin Matrix ◽  
Polyurethane Resin ◽  
Reduced Graphene ◽  
Znfe2o4 Nanoparticles ◽  
Electromagnetic Pollution

Superparamagnetic ZnFe2O4 spinel ferrite nanoparticles were prepared by the sonochemical synthesis method at different ultra-sonication times of 25 min (ZS25), 50 min (ZS50), and 100 min (ZS100). The structural properties of ZnFe2O4 spinel ferrite nanoparticles were controlled via sonochemical synthesis time. The average crystallite size increases from 3.0 nm to 4.0 nm with a rise of sonication time from 25 min to 100 min. The change of physical properties of ZnFe2O4 nanoparticles with the increase of sonication time was observed. The prepared ZnFe2O4 nanoparticles show superparamagnetic behavior. The prepared ZnFe2O4 nanoparticles (ZS25, ZS50, and ZS100) and reduced graphene oxide (RGO) were embedded in a polyurethane resin (PUR) matrix as a shield against electromagnetic pollution. The ultra-sonication method has been used for the preparation of nanocomposites. The total shielding effectiveness (SET) value for the prepared nanocomposites was studied at a thickness of 1 mm in the range of 8.2–12.4 GHz. The high attenuation constant (α) value of the prepared ZS100-RGO-PUR nanocomposite as compared with other samples recommended high absorption of electromagnetic waves. The existence of electric-magnetic nanofillers in the resin matrix delivered the inclusive acts of magnetic loss, dielectric loss, appropriate attenuation constant, and effective impedance matching. The synergistic effect of ZnFe2O4 and RGO in the PUR matrix led to high interfacial polarization and, consequently, significant absorption of the electromagnetic waves. The outcomes and methods also assure an inventive and competent approach to develop lightweight and flexible polyurethane resin matrix-based nanocomposites, consisting of superparamagnetic zinc ferrite nanoparticles and reduced graphene oxide as a shield against electromagnetic pollution.

scholarly journals THEELECTROMAGNETICSHIELDINGBEHAVIOROFLAYERED KNITTED FABRIC STRUCTURES

2019 ◽  
Vol 2019 ◽  
pp. 32-35
Author(s):  
Özlem KAYACAN ◽  
Neza BAKIR ◽  
Barkın TRAŞ
Keyword(s):  
Electromagnetic Waves ◽  
Childhood Leukemia ◽  
Industrial Applications ◽  
Electromagnetic Shielding ◽  
Human Beings ◽  
Shielding Effectiveness ◽  
Technical Textiles ◽  
Fabric Structures ◽  
Electromagnetic Pollution ◽  
Risk Of Cancer

The increase in daily usage of electrical and electronic tools simplify the lives of human beings, on the other hand, they also create an enormous electromagnetic pollution. In industrial applications, electromagnetic shielding materials are used to prevent these electromagnetic signals. The studies on human health against the electromagnetic pollution was determined that the widely usage of these electronic devices increases the risk of cancer. Especially in low frequency fields, the most consistent evidence is obtained in childhood leukemia [1]. In order to reduce the damage of these electromagnetic waves, researches have been still made on the electromagnetic shielding effectiveness. Electrically conductive technical textiles are also investigated for this aim. Different textile structures such as knitted, woven, composite or coated textiles etc and also different conductive yarns are produced to prevent these harmful waves [2-5].In this study, it is aimed to investigate the electromagnetic shielding performances of conductive knitted fabrics. In order to search the efficiency of these fabrics, single jersey and interlock knitted structures are produced. By using these fabrics, two different types of double-layered fabric structures are formed and the shielding effectiveness of these structures are investigated experimentally [6}.

scholarly journals Sandwich-Like Fe&TiO2@C Nanocomposites Derived from MXene/Fe-MOFs Hybrids for Electromagnetic Absorption

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Baiwen Deng ◽  
Zhen Xiang ◽  
Juan Xiong ◽  
Zhicheng Liu ◽  
Lunzhou Yu ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
Impedance Matching ◽  
Two Dimensional ◽  
Carbon Nanosheets ◽  
Good Design ◽  
Absorption Bandwidth ◽  
Functional Nanoparticles ◽  
Electromagnetic Absorption ◽  
Electromagnetic Pollution ◽  
Minimum Reflection Loss

AbstractElectromagnetic pollution has been causing a series of problems in people’s life, and electromagnetic absorbers with lightweight and broad absorbing bandwidth properties are widely desired. In this work, novel sandwich-like 2D laminated Fe&TiO2 nanoparticles@C nanocomposites were rationally designed and successfully developed from the MXene–MOFs hybrids. The formation of Fe and rutile-TiO2 nanoparticles sandwiched by the two-dimensional carbon nanosheets provided strong electromagnetic energy attenuation and good impedance matching for electromagnetic wave (EMW) absorption. As expected, the nanocomposites achieved a broad effective absorption bandwidth of 6.5 GHz at a thickness of only 1.6 mm and the minimum reflection loss (RL) value of − 51.8 dB at 6.6 GHz with a thickness of 3 mm. This work not only provides a good design and fabricating concept for the laminated metal and functional nanoparticles@C nanocomposites with good EMW absorption, but also offers an important guideline to fabricate various two-dimensional nanocomposites derived from the MXene precursors.

scholarly journals Absorption of Electromagnetic Waves by Fe\(_3\)O\(_4\)/Paraffin Composite Materials

2019 ◽  
Vol 29 (1) ◽  
pp. 63
Author(s):  
Hong Thi Minh Nguyen ◽  
Duy Van Nguyen ◽  
Co Dang Nguyen ◽  
Tu Dinh Bui ◽  
Thang Duc Pham
Keyword(s):  
Composite Materials ◽  
Electromagnetic Waves ◽  
Weight Ratio ◽  
Absorption Capacity ◽  
Sample Thickness ◽  
Simulation Calculation ◽  
Absorbing Materials ◽  
Large Dielectric Loss ◽  
Electromagnetic Pollution ◽  
Harmful Effects

Electromagnetic pollution in general and the harmful effects of microwave radiation in particular on environment is currently in the urgent stage. To eliminate the effect of electromagnetic energy the most common methods relies on the use of absorbing materials with large absorption capacities in wide frequency band. In this paper, we investigate the capability of absorption of electromagnetic waves of Fe3O4 nanoparticles in paraffin basis. The Fe3O4/paraffin composite materials were prepared with a weight ratio of 35%/65%. The dielectric constant (εr) and the magnetic permeability (μr) in the frequency (f) range from 8 to 18 GHz were measured for various sample thicknesses. The results indicated a large dielectric loss and strong thickness dependence of absorption capacity. The maximum absorption coefficient (RL) is of order -13.6 dB, corresponding to the achieved absorbance of 96,9% for the 2.6 mm of sample thickness. The experimental results are consisted with our simulation calculation.

Impact of Wi-Fi Electromagnetic Waves on Brainwaves

2014 ◽  
Vol 1079-1080 ◽  
pp. 882-886 ◽  
Author(s):  
Fu Chien Kao ◽  
Shin Ping R. Wang ◽  
Yun Kai Lin ◽  
Chih Chia Chen ◽  
Chih Hsun Huang
Keyword(s):  
Wireless Communication ◽  
Communication Technology ◽  
Cognitive Neuroscience ◽  
Electromagnetic Waves ◽  
Medical Science ◽  
Low Frequency ◽  
Primary Study ◽  
Human Beings ◽  
Wireless Internet ◽  
Financial Transactions

In the era of wireless communication, WiFi becomes an indispensable accessory to most of us. People use WIFI to interact with the wireless Internet, perform commercial and financial transactions, or conducting recreational activities, etc.Though it offers a more convenient life to people, the strong Electromagnetic waves(EMW) resulted from it endangers human health, that has already turned out to be the primary study for medical science. Furthermore, EMW also attracts concern and panic of the inhabitants living in the surroundings which is filled with high-frequency and low-frequency EMwave. EMW today comes from broadcast towers, the system of the wireless communication, GPS, TVs and defense satellites mostly. Enjoying the convenience resulted from communication technology, people nowadays should also concern about whether EM wave would damage people’s health at the same time. Based on the perspective of cognitive neuroscience, this study mainly focuses on how EM wave produced from WiFi affects subject’s brainwaves under a specific physiological situation. The researcher observes different changing of brainwave when human beings expose in various strength of EM wave, and analyses the affection of EMW toward subject’s brainwaves.

Justice, Respect, and Recognition in Mental Health Services

2016 ◽  
Author(s):  
Paul Brodwin
Keyword(s):  
Social Relations ◽  
Health Care Services ◽  
Formal Theory ◽  
Theoretical Models ◽  
Human Beings ◽  
Cultural Discourses ◽  
Care Services ◽  
Psychiatric Survivor ◽  
Interdisciplinary Study ◽  
Harmful Effects

This chapter raises a key question for the interdisciplinary study of health and justice: is dialogue possible between theoretical models and first-person testimony about the harms caused by injustice? To consider this question, the chapter examines the claim that disrespect—the systematic devaluation of others in a way that excludes them from reciprocal social relations—is a form of injustice. The philosopher Stephen Darwall and social theorist Axel Honneth conceptually elucidate the links between justice, respect, and recognition. Their normative arguments offer a high-order conceptual framework for recognizing people’s equal worth as human beings (and the harmful effects of denying such recognition). This chapter compares their abstract frameworks with a landmark autobiography by a founder of the psychiatric survivor movement. The search for commensurability between these texts exposes the precise difference between experience-far and experience-near genres of ethical expression. This chapter adopts a similar approach as DeBruin et al. (this volume) in examining popular cultural discourses in light of formal theory. Both chapters take seriously the lay narratives and forms of ethical argumentation that circulate outside the academy. Both envision a plural ethics of justice and health that acknowledges how ordinary people interpret and respond to institutionalized oppression in health-care services.

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