Thin Metallic Mesh Research Articles

One-Step Fabrication of Semi-Transparent Nanofibrous Lithium-Ion Battery

Flexibility and transparency of batteries greatly expand their application and offer new opportunities to electronic devices making them foldable, bendable, and not obstracting. Herein was proposed a facile and beneficial strategy to solve “hot” issues of such type of batteries by providing a uniform and stable framework for bendable, portable and semi-transparent "all-in-one" lithium-ion batteries (LIBs). The “all-in-one” flexible LIB was fabricated by one-stage electrospinning of PEO and PVDF-HFP-based precursor solution loaded with active materials. The electrochemical performance of the anode and cathode membranes was investigated in lithium half cells. To improve the electron-conductivity, CNTs were introduced inside the nanofibers in anode and cathode parts. The nanofibers containing active materials were successfully fabricated with the use of pre-synthesized nanosized LFP/C and graphite powders and loading them into the electrospinning solutions of the cathode and anode, respectively. The use of the same polymer to produce all three parts of the battery (anode, separator and cathode), as well as optimized electrospinning conditions, made it possible to obtain all-in-one flexible solo membrane. The concept was based on the application of nanofibers containing pre-synthesized active materials without carbonization, sintering or any other post-treatment. The developed “all-in-one” membrane assembled within copper and nickel meshes acting as anodic and cathodic current collectors demonstrated semi-transparency as can be seen from the figure. It is enabled by the swollen polymer fibers network, which provides transparent substrate for nano-sized particles of active materials. Additionally, the thin metallic mesh used as current collectors could maintain the overall transparency of the cell. Alternatively ITO glass and/or membrane with high content of CNT were used as a current collectors to provideimproved transparency and flexibility. Acknowledgment This research is funded by the Committee of Science of the Ministry of Science and Higher Education of the Republic of Kazakhstan (Grant No. BR21882402) Figure 1

The contact problem in FEM analysis of filiform structure for large deployable reflectors

Space reflectors need a continuous increase of size to improve the quality of the communication. Considering the small space available in launchers, the antenna must be assembled within the vector and deployed in the space environment. The antenna requires a thin metallic mesh sustained by an appropriate net structure. The best reflector efficiency is reached when all the metallic wires keep in stable contact, allowing the electrical field to be homogeneous. The number of wires involved is enormous, so that, the modelling requires a simple structural approach connected to a reliable contact tool. Single wires can be modelled by beams, but this opens a non-trivial contact managing. As a matter of fact, the wires describe a thin surface, but the contact is realized by 3D crossing. This point is the main objective of the present work which suggests a way to overcome the crossing while maintaining the structure modelling in a 2D field. The contact efficiency needs that the wires do not exceed the elastic strength, causing a lowering of loading contacts due to irreversible deformations. Taking advantage of the present approach, an investigation over the percentage of active contacts in a full mesh is performed, so that optimally applied tensile loads are identified.

How a Thin Metal Mesh Loaded With T Cells Can Shrink Solid Tumors

How a Thin Metal Mesh Loaded With T Cells Can Shrink Solid Tumors

Energy efficient piezoelectrically actuated transducer for direct-contact ultrasonic drying of fabrics

Current clothes drying technology is an energy-intensive process that involves blowing hot air across tumbling wet fabrics to evaporate water. To address the relatively low energy efficiency of this drying technique, a new cloth drying technology was proposed in our prior study. This technology utilizes high frequency ultrasonic vibrations to extract water from a fabric in the liquid phase, resulting in a dramatical reduction in energy consumption and drying time. A piezoelectrically actuated transducer was designed and fabricated. The transducer design was based on a piezoelectric actuator that excites axisymmetric resonant modes in a thin circular metal mesh. The device was constructed by bonding a piezoelectric ring to a thin metal mesh with a hole diameter of 120 µm. Test results demonstrated that the new ultrasonic transducer efficiently dried clothes at an order of magnitude lower resonant frequency compared with the previous commercial devices, 23 kHz versus 135 kHz. Also, the power consumption per area of the new transducer was an order of magnitude less than the commercial devices. Depending on operating conditions, the device was 3–24 times more efficient compared to the commercial ultrasonic transducers utilized in our prior ultrasonic clothes drying studies.

High-performance hierarchical graphene/metal-mesh film for optically transparent electromagnetic interference shielding

This work first demonstrates the improved electromagnetic interference (EMI) shielding performance of monolayer graphene on highly transparent metal-meshes of random pattern. Metal-meshes are fabricated on quartz substrate by lift-off based on self-cracking template and CVD graphene is directly transferred onto thin metal-meshes to construct the hierarchical graphene/metal-mesh film, by which considerable improvements both in microwave reflection and absorption can be realized in thin metal-meshes. The shielding effectiveness (SE) of the hierarchical film even exceeds the summation of those of the monolayer graphene and the metal-mesh film. Detailed analyses reveal that absorption dominates the improvement in SE for a graphene/50 nm Ag-mesh film, with a three-fold absorption coefficient as well as a slightly increased reflectivity compared to the Ag-mesh itself. The as-prepared hierarchical film primely inherits the excellent optical transmission properties from random-pattern metal-meshes with high transmittance in visual-IR spectrum, low haze and faint diffraction. Moreover, the chemical stability of metal-meshes is highly improved with the protection of graphene. We anticipate that the hierarchical graphene/metal-mesh film can be a promising material to play a great role in realization of high-performance EMI shielding in emerging optoelectronic devices such as touch panels, displays, airborne optoelectronic pods, and aviation camcorders.

Early Loaded Single Implant Reinforced Mandibular Overdenture.

Rehabilitating atrophied mandible with two-implant supported denture is a common treatment modality for implant retained removable overdenture in mandible. This paper aims to design a treatment modality where single implant reinforced overdenture is fabricated for a severely atrophied mandibular ridge with early loading protocol. Results of studies have shown that a single implant mandibular overdenture significantly increases the satisfaction and quality of life of patients with edentulism. Midline fracture of the prosthesis is the most common complication related to single implant and two-implant retained mandibular overdentures. To manage such complication, a thin metal mesh is used to reinforce the overdenture and also to make the prostheses lighter and cost effective as compared to conventional cast metal framework.

Polarization independent broadband terahertz antireflection by deep‐subwavelength thin metallic mesh

AbstractBroadband antireflection coatings for passive terahertz (THz) components are extremely important in the application of THz technology. Metallic nano‐films are commonly used for this purpose. Here a new approach to realize polarization independent broadband antireflection in THz range, based on a meta‐surface design is experimentally demonstrated. The internal reflection of a broadband THz pulse (spectral bandwidth of 0.06 – 4 THz) at a Si/air interface can be fully suppressed with a Cr square mesh with deep‐subwavelength dimensions. Small nonuniformity of the meta‐surface structure can enhance the tolerance on structural parameters for achieving the AR condition. The design concept is applicable to other metals and frequency ranges as well, which opens a new window for future AR coatings.

Inflammatory Response Assessment of a Hybrid Tissue-Engineered Heart Valve Leaflet

Despite substantial research in the past few decades, only slight progress has been made toward developing biocompatible, tissue-engineered scaffolds for heart valve leaflets that can withstand the dynamic pressure inside the heart. Recent progress on the development of hybrid scaffolds, which are composed of a thin metal mesh enclosed by multi-layered tissue, appear to be promising for heart valve engineering. This approach retains all the advantages of biological scaffolds while developing a strong extracellular matrix backbone to withstand dynamic loading. This study aims to test the inflammatory response of hybrid tissue-engineered leaflets based on characterizing the activation of macrophage cells cultured on the surfaces of the tissue construct. The results indicate that integration of biological layers around a metal mesh core-regardless of its type-may reduce the evoked inflammatory responses by THP-1 monocyte-like cells. This observation implies that masking a metal implant within a tissue construct prior to implantation can hide it from the immune system and may improve the implant's biocompatibility.

Fragmentation of hypervelocity aluminum projectiles on fabrics

This paper presents work performed for a study investigating the ability of different flexible materials to induce fragmentation of a hypervelocity projectile. Samples were chosen to represent a wide range of industrially available types of flexible materials like ceramic, aramid and carbon fabrics as well as a thin metallic mesh. Impact conditions and areal density were kept constant for all targets. Betacloth and multi-layer insulation (B-MLI) are mounted onto the targets to account for thermal system engineering requirements. All tests were performed using the Space light-gas gun facility (SLGG) of the Fraunhofer Institute for High-Speed Dynamics, Ernst-Mach-Institut, EMI. Projectiles were aluminum spheres with 5mm diameter impacting at approximately 6.3km/s. Fragmentation was evaluated using a witness plate behind the target. An aramid and a ceramic fabric lead the ranking of fabrics with the best projectile fragmentation and debris cloud dispersion performance. A comparison with an equal-density rigid aluminum plate is presented. The work presented can be applied to optimize the micrometeoroid and space debris (MM/SD) shielding structure of inflatable modules.

Label-free THz sensing of living body-related molecular binding using a metallic mesh

We have demonstrated label-free THz sensing of living body-related molecular binding using a thin metallic mesh and a polyvinylidene difluoride (PVDF) membrane. Metallic meshes in the THz region are designed for anomalous transmission phenomena derived from a resonant excitation of surface waves. Additionally, they are designed to have a sharp dip in transmittance. The metallic mesh is very sensitive to a change of the refractive index of materials attached to the metallic mesh. In this paper, we report sensing of interactions between lectin and sugar using this technique. We found that the dip frequency shift, transmittance attenuation of the dip frequency, and peak shift of the derivative spectrum of the phase shift depend on the bonding amount of lectin–sugar interactions. We also applied this technique to detect avidin–biotin interactions, leading to the detection of a small amount of biotin (0.17pg/mm2).

Development of New X-Ray Source Based on Carbon Nanotube Field Emission and Application to the Non Destructive Imaging Technology

In the present work, a new concept of X-ray source was developed. The conventional thermionic tungsten filament tube is commonly available in various fields of application, such as, medical diagnostic and therapy system, microwave amplifier, non-destructive testing (NDT) technology, and so on. However, it has intrinsic problems such as high power consumption, very low X-ray efficiency, and out-gassing problems. Therefore, in the present study a new carbon nanotube (CNT) based X-ray source was developed as a substitute for the conventional one. The new X-ray source consists of three major parts. The CNT electron field emitter was employed as a cathode, a very thin metal mesh as a grid to extract electrons from the CNT, and finally a molybdenum embedded copper target as an anode to accelerate electrons. A supplementary electrostatic focusing lens was employed in the tube to focus the electron beam on the anode target. A detailed description of the tube structure as well as electron beam characteristics is presented in this study. In addition, preliminary X-ray images obtained by using the CNT X-ray tube are presented.

Terahertz sensing method for protein detection using a thin metallic mesh

A label-free biological sensor, which is based on the resonant transmission phenomenon of a thin metallic mesh, is proposed in the terahertz wave region. By using this sensor, we demonstrate the highly sensitive detection of small amounts of protein horseradish peroxidase. For quantitative investigation of the sensitivity of our sensor, horseradish peroxidase was printed on the metallic mesh surface by using a commercial available printer. A distinct shift of the transmission dip frequency is observed for 500pg∕mm2 (11fmol) of horseradish peroxidase printed on the metallic mesh, indicating the significantly high sensitivity of our sensor.

Photonic states deep into the waveguide cutoff frequency of metallic mesh photonic crystal filters

We examine the optical properties of three-dimensional metallic photonic crystals made from a periodic stacking of thin metallic mesh layers separated by homogeneous dielectric films by means of a combination of the plane-wave-based transfer-matrix method and analytical modal solution approach. Although each metallic mesh layer can serve as a frequency-selective surface and involves an intrinsic long-wavelength waveguide cutoff to electromagnetic waves, pass bands and new band gaps can exist far below the cutoff frequency due to the global coupling effect among different mesh layers. The results for the transmission spectra and photonic band structures are in good agreement with existing experimental measurements. It is found that the position of the pass bands and band gaps strongly depends on the thickness and composite of the separation layer between the adjacent metallic mesh layers.

Validity and accuracy of equivalent circuit models of passive inductive meshes. Definition of a novel model for 2D Grids

Accuracy of equivalent circuit models of periodic grids is investigated in amplitude and phase in the visible region. The grids studied here are one-dimensional (1D) and two-dimensional (2D) inductive thin metal meshes. They are located in free space and are illuminated by a plane wave under normal incidence. The range of validity and the accuracy of conventional circuit models are defined by comparison with rigorous results obtained with the Finite-Difference Time-Domain (FDTD) method. In particular, it is shown that electrical models of 1D grids are accurate, whereas equivalent circuits of 2D grids should be used very cautiously. Then, a new formulation is proposed to overcome this major drawback. In the non-diffraction region, the agreement between our model and the FDTD results is within 2% for the power reflectivity and 1° for the phase over a very wide range of strip widths.

Transmission line model of substrate effects on capacitive mesh couplers

To use a transmission line model to calculate the optical properties of a thin metal mesh on a dielectric substrate, account must be taken not only of the different propagation conditions within the substrate and of Fabry-Perot resonances due to reflections at the second surface, but also of the effect of the dielectric on the capacitive component of the equivalent reactance of the mesh. Only when this effect is accounted for, which can be done using a simple formula based on Babinet's principle, is good agreement obtained with experimental measurements.

STENCIL METHODS FOR PREPARING MOIRE GRIDS

Three methods are described for depositing moiré grids on specimens by means of thin metal meshes produced by electroforming. The methods involve printing, electro‐etching, vacuum deposition, with the mesh used as a stencil, and they are capable of accurately reproducing grids with line densities of 2000 lines/in (80 lines/mm) and of giving good contrast.

Far-infrared properties of metallic mesh and its complementary structure

The optical properties of thin metallic mesh (“inductive” grids) are compared theoretically and experimentally with the properties of the complementary structure (“capacitive” grids). Close interrelations are found. In the non-diffraction region (wavelength > grid constant), the optical properties of both types of grids can be described by simple transmission line equivalent circuits. The circuit parameters are determined as functions of the dimensions of the grids. This representation allows a fairly accurate calculation of interference filters consisting of two or more grids of either type. The new capacitive grids may be used advantageously in interference filters with non-harmonic lying orders, in filters with strongly differing peak transmissions, and in effective low-pass filters in the very far-infrared.