Plasmonic cloaking is one of the Invisibility methods which is very attractive for researchers. Despite of non-perfect nature of this method there are some advantages such as easier practical realization for it. In this paper, considering cylindrical layered metamaterial with composition of graphene and TiO2 layers, wave equation is solved for this structure analytically. After calculating scattering cross section, Invisibility Condition is investigated in the structure. Then, the effect of changing in some geometrical and physical parameters such as chemical potential, core radius and number of layers on Invisibility Condition is analyzed. Some numerical simulation using COMSOL approve the results.

Invisibility is one of the aspirations of human beings that the optics and materials have made, and metamaterials make this achievable. Metamaterials have amazing optical properties, including a negative refractive index, which are not found in nature and must be prepared with special techniques. Normally, the light that hits an opaque object is reflected from it and becomes visible. Metamaterials transform this two-way relationship between light and objects so that the light changes its direction around the object without being reflected and passing through it. In this case, the object becomes invisible because no light is visible. In this article, general information about how objects become invisible and methods of preparing metamaterials will be presented by using the principles of light physics and explaining the phenomena of light refraction and surface plasmon.

Study the titles of body organs as well as counting them in the anatomical texts of humoural medicine indicates an important issue: in these texts and in comparison with modern anatomical texts, there is no mention of a significant number of body organs. This is while these two different conclusions are the result of the observations of the same action: the dissection of the corpse. In addition, some of these organs are visible to the naked eye, including lymphatic vessels. Therefore, the humoural physician has seen some organs in the process of dissection, but has not. According to the authors of this article, the reason for the Invisibility of these organs lies in the connection between observation and theory. In short, the observation of the humoural physician's dissection practice, unlike the observation of the modern anatomist dissection practice, has been based on the humoural theory. Hence, the humoural physician, in the process of dissection, has seen organs which have a humoural function. The rest of the body organs were either not seen or reduced to a fleshy appendages.

Photonic crystals are structures that can control the propagation of light by creating periodic changes in the refractive index. These structures facilitate directing electromagnetic waves in specific directions and making objects invisible by creating a bandgap. Photonic crystals, as microscopic structures with unique optical properties, are used in the design of Invisibility systems. However, the design and optimization of these structures, especially with new methods like deep learning, have not been thoroughly investigated. Utilizing deep learning techniques can be highly beneficial in this area. Therefore, this paper employs the deep neural network architecture ResNet to optimize photonic crystals. ResNet can assist designers in selecting suitable materials and determining the optimal dimensions and arrangements of photonic nanostructured crystals for Invisibility by extracting complex and nonlinear features from input data. The phenomenon of negative refraction in photonic crystals and the way light propagates in the proposed Invisibility were studied using FDTD simulation. The results indicated that appropriate design of photonic crystals using deep learning could contribute to the creation of efficient structures.

The main purpose of this article is to use metasurfaces to make objects invisible. The process is that, after examining how to analyze the electromagnetic plan metasurface of the plate, a method for the analysis of cylindrical metasurfaces is presented. Then, inspired by the modeling of plan metasurfaces, a method based on the physical characterization of cylindrical metasurfaces in order to model and extract their tensor parameters is expressed. The methods presented in this paper for analyzing, modeling and extracting the parameters of cylindrical metasurfaces can be implemented for any desired type of linear metasurfaces in a wide frequency range consisting of radio and microwave waves to light waves. In the next step, the proposed formulation is used to reduce the scattering of electromagnetic waves from objects or so-called Invisibility. The proposed method for Invisibility makes it possible to provide different configurations of metasurfaces to achieve any type of Invisibility according to the limitations of practical implementation. In addition, the formulation is effective in providing a physical understanding and description of Invisibility. To test the results, the formulation of this paper was applied to a designed metasurface sample. Finally, with the help of full-wave simulations, the metasurface tensor parameters are extracted and the desired Invisibility is realized.

Monitoring and evaluation of transformers are essential to prevent their insulation failure. In this paper, the use of 2-furan-carboxaldehyde (2-FAL) and methanol (MeOH) concentrations as the main products of paper insulation degradation, and insulation Condition markers, has been studied. In order to study the degradation process and production of degradation products, the thermal aging process of the transformer insulation system was implemented in laboratory Conditions. The results of laboratory studies show that in the early stages of degradation the amount of MeOH is significant compared to 2-FAL. Also, the estimation of the degree of polymerization (DP) in the early stages of degradation (DP>800) through MeOH concentration and with decreasing DP (DP <800) through 2-FAL concentration is closer to the real value. The results of studies performed on 35 distribution transformers confirm the production of significant amounts of MeOH in the early stages of degradation. Also, the estimated DP values for the studied transformers were obtained through 2-FAL and MeOH concentration. The results show that estimating the amount of DP through MeOH concentration is associated with a probability of error of about 9% compared to estimating DP through 2-FAL concentration.