Good Absorption Characteristics Research Articles

Prediction of the photovoltaic performance of the lead-free layered Ruddlesden–Popper organic–inorganic perovskite (CH3NH3)2GeI4

Using the density functional theory (DFT) and the spectral limited maximum efficiency (SLME) model, we thoroughly evaluate the material MA2GeI4 as a prospective absorber for photovoltaic applications. This material belongs to the family of layered material organic-inorganic Ruddlesden-Popper perovskites, which have attracted interest due to their stability. Our first-principles calculations show that MA2GeI4 has a direct bandgap that is suitable for light absorption at 1.37 eV. To understand the source of its exceptional optical properties, the electronic structure, density of states, and optical properties were examined. Also, we used the SLME model to estimate the MA2GeI4 solar cell efficiency. The latter was found to be about 32.6% power conversion efficiency. The material’s excellent absorption and promising photovoltaic properties contribute to its high efficiency, even when quantum confinement occurs between layers. We found that MA2GeI4 is a potential absorber material for solar applications, demonstrating both good absorption characteristics and advantageous electrical properties. This discovery lays the path for additional experimental investigation of MA2GeI4 based solar cell.

In silico Analysis of Natural Inhibitors against HPV E6 Protein.

Drug re-purposing is one of the cost-effective methods to establish novel therapeutics against many diseases. Established natural products are collected from databases and used to potentially screen them against HPV E6 protein, a critical viral protein. This study aims to design potential small molecule inhibitors against HPV E6 protein using structure-based approaches. Ten natural anti-cancerous compounds (Apigenin, Baicalein, Baicalin, Ponicidin, Oridonin, Lovastatin, Triterpenoid, Narirutin, Rosmarinic Acid, and Xanthone) were selected by review of the literature. These compounds were screened using Lipinski Rule of Five. Out of ten compounds, seven were found to satisfy Rule of five. Docking of these seven compounds was carried out using AutoDock software and corresponding Molecular Dynamics Simulations were performed by GROMACS. Among the seven compounds docked with the E6 target protein, six compounds showed lesser binding energy than the reference compound, Luteolin. The three-dimensional structures of E6 protein and the corresponding ligand complexes were visualised and analysed using PyMOL whereas the two-dimensional images of protein-ligand interactions were obtained by LigPlot⁺ software to study the specific interactions. ADME analysis using SwissADME software revealed that all the compounds except Rosmarinic acid have good gastrointestinal absorption and solubility characteristics while Xanthone and Lovastatin showed blood brain barrier penetration properties. Considering the binding energy and ADME analysis, Apigenin and Ponicidin are found to be most suitable for de novo</i> designing of potential inhibitors against the HPV16 E6 protein. Further, synthesis and characterization of these potential HPV16 E6 inhibitors will be carried out and their functional evaluation using cell culture-based assays will be undertaken.

A Ball-Contacting Dynamic Vibration Absorber with Adjustable Stiffness and Nonlinear Characteristics

Structural vibration has always been a major concern in the engineering field. A dynamic vibration absorber in the form of contacts with adjustable stiffness (CDVA) offers effective vibration suppression and can improve conventional dynamic vibration absorbers with high sensitivity to frequency deviation and difficulty in adjusting the frequency. In this research, first, based on the theoretical model of the contact between a rubber ball and an inner cone, the feasibility of changing the axial contact state to change the structure’s natural frequency was verified using an ANSYS simulation. A theoretical model of the static contact stiffness between the ball and the inner cone was constructed using Hertzian contact theory and Hooke’s law, and a theoretical model of the cubic nonlinear elastic restoring force was used to characterize the stiffness properties of the rubber ball during compressive rebound. The steady-state frequency response equations of the main vibration structure were derived using the averaging method in conjunction with the two-degree-of-freedom dynamics model, and the stability of the solutions to the frequency response equations was obtained in conjunction with the stability determination criterion. Then, the impact of the CDVA’s design parameters on the nonlinear dynamic response of the primary vibration structure was simulated and analyzed. The resulting findings can serve as guidance for designing dynamic vibration absorber parameters. Based on the principles of ball-inner cone contact, a dynamic vibration absorber structure was proposed. A design test was conducted to verify the correctness of the contact stiffness model, and an experimental study was carried out to investigate the law of change in the dynamic stiffness and damping of the principle structure of CDVA under dynamic excitation conditions. Finally, the vibration test platform of the solidly supported beam structure was constructed, and vibration suppression tests of the CDVA in different compression states were conducted to investigate the tunability and feasibility of CDVA vibration suppression. The results showed that the dynamic vibration absorber had good vibration absorption characteristics and could be used for single-mode vibration suppression of multimodal main structures.

Generation of stable femtosecond pulses using MoS2−xSex as the saturable absorber in Er-doped fiber laser

A new transition-metal dichalcogenide (Janus TMDs), molybdenum selenide sulfide (MoS[Formula: see text][Formula: see text]Se[Formula: see text]), has attracted wide attention due to its unique and highly stable alloy structure, high carrier mobility and the ability to modulate the band gap based on composition. In this work, MoS[Formula: see text][Formula: see text]Se[Formula: see text] nanosheets were prepared through liquid phase exfoliation and further prepared as a saturable absorber (SA). The nonlinear optical response was investigated by the homemade balanced twin-detector measurement system, revealing the potential of MoS[Formula: see text][Formula: see text]Se[Formula: see text]-SA in ultrafast photonics. The SA devices exhibited good saturation absorption characteristics. By applying it to the Er-doped fiber laser, a stable mode-locked fiber laser based on MoS[Formula: see text][Formula: see text]Se[Formula: see text]-SA was successfully achieved. The pulse width was measured to be 509 fs, with a spectral width of 6.33 nm and a maximum output power of 7.44 mW in the mode-locked state. This is the first reported instance of achieving mode-locking operation in the Er-doped fiber laser using MoS[Formula: see text][Formula: see text]Se[Formula: see text]-SA, indicating its great potential for applications in ultrafast photonics.

Oxygen vacancies based BiOBr nanoflowers saturable absorber and its application in Q-switched mode-locked infrared laser

In this work, BiOBr nanoflowers with oxygen vacancies as saturable absorber are prepared using hydrothermal method. Passively Q-switched mode-locked infrared laser is achieved. The output power reaches the maximum 312 mW. The minimum Q-switched envelope is 242 ns with the maximum repetition rate of 180.5 kHz. Meanwhile, the mode-locked pulse duration within the Q-switched envelope is approximately 315 ps with repetition rate of 232 MHz. The results of X-ray diffraction (XRD), Electron paramagnetic resonance (EPR), UV–Vis–NIR diffuse reflectance spectra, and X-ray photoelectron spectroscopy (XPS) demonstrate the oxygen vacancies introduce intermediate energy levels in the energy band of BiOBr, which enhances the optical absorption in the near-infrared region. Therefore, BiOBr saturable absorber exhibits good saturable absorption characteristics in the near-infrared region and is a promising modulation element in Q-switched mode-locked infrared lasers.

Bifunctional S-scheme CdSSe/Bi2WO6 heterojunction catalysts exhibit generalized boosting performance in photocatalytic degradation of tetracycline hydrochloride, photoelectrochemical and electrocatalytic hydrogen production

In this work, by a simple method of hydrothermal synthesis, the CdSSe/Bi2WO6 S-scheme heterojunction catalyst is successfully obtained and the results are verified by XPS, EPR, band structure, etc. The S-scheme heterojunction can maintain the strong redox potential energy position of both catalysts, and adjust the electron transfer path to improve the electron-hole separation efficiency, and thus improve the charge transfer efficiency. CdSSe has a high conduction band (−1.13 eV) and a narrow bandgap width (1.59 eV), exhibiting good light absorption characteristics and reduction ability; the valence band position of Bi2WO6 is much low (2.58 eV), indicating good oxidation activity. This heterojunction has excellent oxidation and reduction capabilities and exhibits multifunctional catalysts. Its photocatalytic degradation ability of tetracycline hydrochloride is 2.2 times that of the original CdSSe, while its photoelectrochemical activity is 11 times that of CdSSe, reaching a photocurrent density of − 2.081 mA/cm2 at 0 V (vs. RHE). The electrocatalytic activity of its hydrogen evolution has also been enhanced. This study developed a design strategy for a novel bifunctional S-scheme heterojunction catalyst.

Preparation of Bi2Te3 Based on Saturable Absorption System and Its Application in Fiber Lasers

Fiber laser is a fundamental component of laser systems and is of great significance for development of laser technology. Its pulse output can be divided into Q-switched and mode-locked. Achieving ultrashort pulse with narrower pulse duration and higher power is the focus of current research on mode-locked lasers. As an important component of fiber laser systems, saturable absorber (SA) can modulate losses in the optical cavity and generate pulses, enabling the laser system to achieve pulse output under long-term normal operating conditions better. Therefore, expanding the selection range of materials with better saturable absorption properties to improve the quality of pulse output is an important topic in current research. Here, the second generation topological insulator Bi2Te3 single crystal is prepared, and a ring fiber laser system is built with the Bi2Te3 SA. The mode-locked pulse with a pulse duration of 288 fs and a signal-to-noise ratio of 80.202 dB is realized. This result verifies that Bi2Te3, as a member of topological insulator, has good saturable absorption characteristics, and has broad prospects for the application research in lasers.

Optimization of Nanofluid Flow and Temperature Uniformity in the Spectral Beam Splitting Module of PV/T System

The mass fraction of 0.01 wt% ZnO nanofluid was prepared via the two-step method. The measurement verifies that ZnO nanofluids have better transmission characteristics in the frequency division window range of 400–1200 nm. At the same time, it has good absorption characteristics in ultraviolet and near-infrared bands, which meets the application conditions of the spectral beam-splitting module of the PV/T system. A spectral beam-splitting module of the PV/T system was designed. The simplified physical model was established in ANSYS 14.0. The flow field and convective heat transfer were simulated for different arrangements of the interlayer inlet to obtain a more ideal and uniform temperature distribution to improve the system’s comprehensive efficiency. The results show that the fluid flow in the interlayer under case II is more uniform, and the temperature field distribution is better than other arrangements. Hence, this work could provide a reference for optimising nanofluid flow within a spectral beam-splitting module.

Double-negative metamaterial square enclosed Q.S.S.R For microwave sensing application in S-band with high sensitivity and Q-factor

Metamaterials have gained much attention due to their exciting characteristics and potential uses in constructing valuable technologies. This paper presents a double negative square resonator shape metamaterial sensor to detect the material and its thickness. An innovative double-negative metamaterial sensor for microwave sensing applications is described in this paper. It has a highly sensitive Q-factor and has good absorption characteristics approximately equal to one. For the metamaterial sensor, the recommended measurement is 20 by 20 mm. Computer simulation technology (C.S.T.) microwave studios are used to design the metamaterial structure and figure out its reflection coefficient. Various parametric analyses have been performed to optimize the design and size of the structure. The experimental and theoretical results are shown for a metamaterial sensor that is attached to five different materials such as, Polyimide, Rogers RO3010, Rogers RO4350, Rogers RT5880, and FR-4. A sensor’s performance is evaluated using three different thicknesses of FR-4. There is a remarkable similarity between the measured and simulated outcomes. The sensitivity values for 2.88 GHz and 3.5 GHz are 0.66% and 0.19%, respectively, the absorption values for both frequencies are 99.9% and 98.9%, respectively, and the q-factor values are 1413.29 and 1140.16, respectively. In addition, the figure of merit (FOM) is analyzed, and its value is 934.18. Furthermore, the proposed structure has been tested against absorption sensor applications for the purpose of verifying the sensor's performance. With a high sense of sensitivity, absorption, and Q-factor, the recommended sensor can distinguish between thicknesses and materials in various applications.

BiVO4 As a Sustainable and Emerging Photocatalyst: Synthesis Methodologies, Engineering Properties, and Its Volatile Organic Compounds Degradation Efficiency.

Bismuth vanadate (BiVO4) is one of the best bismuth-based semiconducting materials because of its narrow band gap energy, good visible light absorption, unique physical and chemical characteristics, and non-toxic nature. In addition, BiVO4 with different morphologies has been synthesized and exhibited excellent visible light photocatalytic efficiency in the degradation of various organic pollutants, including volatile organic compounds (VOCs). Nevertheless, the commercial scale utilization of BiVO4 is significantly limited because of the poor separation (faster recombination rate) and transport ability of photogenerated electron-hole pairs. So, engineering/modifications of BiVO4 materials are performed to enhance their structural, electronic, and morphological properties. Thus, this review article aims to provide a critical overview of advanced oxidation processes (AOPs), various semiconducting nanomaterials, BiVO4 synthesis methodologies, engineering of BiVO4 properties through making binary and ternary nanocomposites, and coupling with metals/non-metals and metal nanoparticles and the development of Z-scheme type nanocomposites, etc., and their visible light photocatalytic efficiency in VOCs degradation. In addition, future challenges and the way forward for improving the commercial-scale application of BiVO4-based semiconducting nanomaterials are also discussed. Thus, we hope that this review is a valuable resource for designing BiVO4-based nanocomposites with superior visible-light-driven photocatalytic efficiency in VOCs degradation.

Synthesis, Characterization, and Electromagnetic Wave Absorbing Properties of La&lt;sub&gt;0.7&lt;/sub&gt;Sr&lt;sub&gt;0.3&lt;/sub&gt;MnO&lt;sub&gt;3&lt;/sub&gt;

Perovskite manganese La&lt;sub&gt;0.7&lt;/sub&gt;Sr&lt;sub&gt;0.3&lt;/sub&gt;MnO&lt;sub&gt;3&lt;/sub&gt; (LSMO) powders were prepared by sol-gel synthesis and calcination in the temperature (&lt;i&gt;T&lt;/i&gt;) range of 500~1200 o C and their structures and electromagnetic (EM) wave absorption properties were investigated. X-ray diffraction (XRD) analysis revealed that the crystalline perovskite phase can be formed at &lt;i&gt;T&lt;/i&gt; ≥ 600 &lt;sup&gt;o&lt;/sup&gt;C. The average grain size was ~15 nm at the calcination temperature (T&lt;sub&gt;cal&lt;/sub&gt;) = 600 &lt;sup&gt;o&lt;/sup&gt;C and it increased to ~1 μm when T cal increased up to 1200 &lt;sup&gt;o&lt;/sup&gt;C. &lt;i&gt;M&lt;/i&gt;-&lt;i&gt;H&lt;/i&gt; curves of the samples showed soft magnetic behaviors for all the crystallized samples, and the value of saturation magnetization increased with increasing &lt;i&gt;T&lt;/i&gt;&lt;sub&gt;cal&lt;/sub&gt;. The real and imaginary parts of permittivities and permeabilities were measured on LSMO powder-epoxy (10 wt%) composites using a network vector analyzer in the frequency range of 100 MHz ≤ &lt;i&gt;f&lt;/i&gt; ≤ 18GHz. The complex permittivities (ε', ε") increased significantly in samples calcined above 800 &lt;sup&gt;o&lt;/sup&gt;C because the concentration of free electrons increased, due to the LSMO's unique magnetotransport effect, as the crystallinity and the &lt;i&gt;M&lt;/i&gt;&lt;sub&gt;S&lt;/sub&gt; value increased significantly. As the &lt;i&gt;T&lt;/i&gt;&lt;sub&gt;cal&lt;/sub&gt; increased, the height of the μ' and μ" spectra also gradually increased. The large values of ε', ε" of the LSMO-epoxy are dominant factors in the EM wave absorption characteristics, and it showed good absorption characteristics when it had a thickness of 1.5 mm or less at a frequency of 12 GHz or higher. At the same time, it also exhibited EM wave shielding ability by reflection in the several GHz band.

Dual-pathway optimization on microwave absorption characteristics of core–shell Fe3O4@C microcapsules: Composition regulation on magnetic core and MoS2 nanosheets growth on carbon shell

Core-shell Fe3O4@C composites with unique configuration and complementary loss mechanisms are widely considered as a kind of prospective functional materials in the field of microwave absorption. However, the balance between core–shell configuration and intrinsic loss is always a thorny problem on the way of good microwave absorption characteristics. Herein, we propose a dual-pathway optimization strategy to consolidate the electromagnetic functions of core–shell Fe3O4@C microcapsules for the first time. On one hand, the chemical composition of magnetic core is finely regulated from Fe3O4 to metal Fe, and it is found that both magnetic loss and dielectric loss can be strengthened effectively through the partial reduction of Fe3O4 core. On the other hand, MoS2 nanosheets are closely anchored on the surface of carbon shell, which can bring more powerful interfacial polarization and dipole polarization to compensate the insufficient dielectric loss caused by the limited thickness and graphitization degree of carbon shell. With the multiple benefits from the dual-pathway optimization strategy, the optimal composite will present good microwave absorption performance, whose effective absorption bandwidth (EAB) and minimum RL value are 5.4 GHz (d = 1.8 mm) and −36.1 dB (5.9 GHz, 4.0 mm), respectively. In particular, its specific EABs (EAB per unit thickness) in different bands are superior to those of most microwave absorbing materials with similar chemical composition. These results demonstrate that this dual-pathway optimization will open a new avenue to enhance microwave absorption performance of core–shell composites in the future.

UTILIZATION OF Zn-DISPERSED WASTE MATERIALS FOR REALIZING THIN META-STRUCTURE WITH IMPROVED MICROWAVE ABSORPTION

In the present work, emphasis has been given on the utilization of waste materials to make cost-effective microwave absorbing composites. Rice husk and exhausted activated charcoal (EAC) were used as waste material, where rice husk is a form of agricultural waste and exhausted activated charcoal was extracted from an exhausted water filter cartridge. Thereafter, zinc metal powder was dispersed in different weight ratios in the mixture of rice husk and exhausted activated charcoal using a planetary ball mill. The X-ray fluorescence (XRF), X-ray diffraction (XRD), and the particle size analyses were done to analyze element composition and particle size. For dielectric properties analysis, vector network analyzer (VNA) was used. Results reveal that composites have the potential for microwave absorption in 2-18 GHz frequency range, sample RHZ 3 having 6 wt.&amp;#37; Zn content gives the maximum reflection loss value of -21.27 dB at 9.2 GHz for a material thickness of 13.9 mm. The experimental results were then used to design a metamaterial microwave absorber. The simulated results show the good microwave absorption characteristics. The metamaterial absorber showed an absorption bandwidth of around 4.1 GHz which ranges from frequency of 14.1 GHz to 18.2 GHz at total thickness of 1.7 mm.

Synthesis of Novel 3-Butylphthalide Derivatives Containing Isopentenylphenol Moiety as Potential Antiplatelet Agents for the Treatment of Ischemic Stroke.

In order to find novel antiplatelet drugs for the treatment of ischemic stroke, a series of 3-butylphthalide derivatives containing isopentenylphenol moiety were designed, synthesized and characterized with spectroscopic analyses. The in vitro antiplatelet activity results indicated that compound 3 better inhibited the arachidonic acid (AA) induced platelet aggregation than aspirin (ASP) and 3-butylphthalide (NBP). Additionally, compared with precursor NBP, compound 3 possessed outstanding antithrombotic activity in the animal experiment model, which could effectively alleviate the formation of tail thrombus and carotid artery thrombus in mice. More importantly, intraperitoneal administration of compound 3 can well protected the rats against ischemia/reperfusion-induced brain injury. Further pharmacokinetic (PK) assay indicated that compound 3 had good absorption characteristics and metabolic stability in vivo. Overall, the present research provides a new candidate compound for the treatment of ischemic stroke caused by platelet aggregation.

Investigation of Mechanical, Thermal, and Moisture Diffusion Behavior of Acacia Concinna FIBER/POLYESTER Matrix Composite

ABSTRACT Acacia concinna is a climber shrub commonly found in the warm plains of central and south India, and it is an excellent herbal remedy for hair. In this investigation, fiber has been extracted from the stem portion of the Acacia concinna plant through the retting process; subsequently, the fibers were cut into 40 mm length. A part of extracted fibers were treated with 3% alkali concentration, and the remaining was kept as an untreated form. Composites were fabricated with raw and treated Acacia concinna fibers separately using a compression moudling process. During composite fabrication, five different fiber weight fraction was maintained, such as 10%, 20%, 30%, 40%, and 50%. Tensile, flexural, impact, hardness, moisture diffusion, and thermal properties were analyzed on the alkali-treated, and untreated fiber reinforced composites. The alkali-treated composite with 30% fiber weight fraction showed good tensile strength (129.38 ± 5.3 MPa), tensile modulus (1.986 GPa), flexural strength (137.31 MPa), flexural modulus (2.86 GPa), impact property (18.61 J/cm2), hardness property (95 HRRW) and water absorption characteristics (4.9%). SEM analysis confirms the improved surface of the alkali-treated composite material.

Study of Composite Bricks from Sawdust and Cement

Abstract: Many timber producing countries generate more than 2 million m3 of sawdust annually. In developing countries, sawdust is often disposed of by open dumping, open burning, or dumping in landfills. The majority of wood sawdust wastes is accumulated from the countries all over the world and causes certain serious environmental problems and health hazards. This poses huge environmental challenges related to air pollution, greenhouse gas emission and destruction of plant and aquatic life. Finding from this experiment that sawdust can be used to make sawdust construction composites with good water absorption and strength characteristics. In this experiment concludes that partially replacing 10%, 20% and 30% of sawdust with sand and cement. Sawdust composites are also attractive for their low thermal conductivity, high sound absorption and good sound insulation characteristics. These findings indicate that increased utilization of sawdust composites in construction will mitigate against potential sawdust environmental pollution, conserve energy and reduce disposal costs. It shows a potential to be used for walls, wooden board substitute, economically alternative to the concrete blocks, ceiling panels, sound barrier panels, etc. Keywords: Sawdust, Sawdust Composites, Thermal Conductivity, Sound Absorption, Sound Insulation etc.

Analysis of Sheep Wool-Based Composites for Building Insulation.

The aim of this paper is to propose ecological thermal insulation materials that meet the goals of sustainability but also fulfill the imposed thermal performance requirements. This paper studies new composite materials based on sheep wool from the perspective of thermal conductivity. The composites were prepared using two types of binder: acrylic-polyurethane resin and natural rubber latex, which were applied to the wool fibres through different methods and percentages. Based on the obtained results of thermal conductivity, two types of samples were selected for further analysis, which aimed to determine the microstructure, chemical composition, water absorption, attack of microorganisms, water vapour permeability, hygrothermal adsorption characteristics and sound absorption of the samples. In order to analyse the variation of thermal conductivity, the following parameters were taken into account: thickness, density, type of binder and percentage of binder. Following the obtained results, it was observed that the value of the thermal conductivity of the samples varies between 0.0324 and 0.0436 W/mK. It was found that all the samples prepared and analysed in this study fulfil the national criteria for the thermal performance of thermal insulation material. After conducting the in-depth analysis of the two selected sample types, it was concluded that both materials have good sound absorption characteristics over the considered frequency range. In addition, as it was expected from the natural fibres, the samples had low resistance against the attack of microorganisms and water-related tests.

A comparative investigation of the optical properties of polar and semipolar GaN epi-films grown by metalorganic chemical vapor deposition

We report on the structural and optical properties of polar gallium nitride on c-plane sapphire substrates and semi-polar (11–22) GaN films on m-plane sapphire substrates by metalorganic chemical vapor deposition. Polar GaN on c-plane sapphire and semi-polar GaN on m-plane sapphire both show good crystal quality, luminescence, absorption, and Raman characteristics. GaN on c-place sapphire shows a high crystal quality as compared to GaN on m-plane sapphire. Surface roughness of polar GaN is lesser than semi-polar GaN. The biaxial structural stress in GaN switches from compressive to tensile as the temperature is increased. This stress-switch temperature is higher in GaN/c-plane than GaN/m-plane. GaN in polar and semi-polar orientation shows ultraviolet emissions but yellow-emissions are only observed in GaN/c-plane sapphire. Raman spectroscopy-related oscillations show systematic variations with temperature in both GaN configurations (polar and semi-polar). This work provides a framework of characterizations for GaN with different crystal polarities. It contributes towards identifying suitable crystal growth mechanisms based on the application and requirements for doping (In, Al, etc), crystal quality, emission, absorption, and photonic oscillations.

Recent Advances in Transition-Metal Based Nanomaterials for Noninvasive Oncology Thermal Ablation and Imaging Diagnosis.

With the developments of nanobiotechnology and nanomedicine, non-invasive thermal ablation with fewer side effects than traditional tumor treatment methods has received extensive attention in tumor treatment. Non-invasive thermal ablation has the advantages of non-invasiveness and fewer side effects compared with traditional treatment methods. However, the clinical efficiency and biological safety are low, which limits their clinical application. Transition-metal based nanomaterials as contrast agents have aroused increasing interest due to its unique optical properties, low toxicity, and high potentials in tumor diagnosis. Transition-metal based nanomaterials have high conversion efficiency of converting light energy into heat energy, good near-infrared absorption characteristics, which also can targetedly deliver those loaded drugs to tumor tissue, thereby improving the therapeutic effect and reducing the damage to the surrounding normal tissues and organs. This article mainly reviews the synthesis of transition-metal based nanomaterials in recent years, and discussed their applications in tumor thermal ablation and diagnosis, hopefully guiding the development of new transition metal-based nanomaterials in enhancing thermal ablation.

Circular ring shaped ultra-wideband metamaterial absorber with polarization insensitivity for energy harvesting

&lt;span&gt;A circular ring-shaped metamaterial (CRM) absorber was designed to harvest radio frequency (RF) energy in the ultra-wideband (UWB) frequency band applications. The proposed metamaterial unit cell features a circular shaped structure, with rectangular strip lines connected in the form of a cross leaving a square shaped slot at center. The unit cell dimensions are 15×15×1.6 mm. The absorber was etched on a low cost FR4 substrate having a dielectric constant of 4.4. Ansys high frequency structure simulator (HFSS) software was used for simulation and the analysis were carried out for unit cell, 2×2, 3×3, and 4×4 array structures. The absorber parameters plotted are absorption characteristics and reflection characteristics. Also, the metamaterial parameters (μeff) and (εeff) are also retrieved from the absorber parameters and analyzed. From the analysis, the values (μeff) and (εeff) were found to be negative, leaving refractive index also negative (n&amp;lt;0), which proved the metamaterial property. The proposed CRM absorber showed good absorption characteristics of more than 80% and also metamaterial property in the entire UWB band (4-13 GHz). Hence the absorber proves to be a good candidate in powering low power sensors/microcontrollers for internet of things (IoT) applications.&lt;/span&gt;