Multilayer Technology Research Articles

Underground Hydrogen Storage: Comparison of High-pressure Hydrogen, Liquid Hydrogen, and Ammonia

One of the alternatives for effective storage of irregularly produced renewable energy is hydrogen energy. In order to realize a hydrogen-based society, not only environmentally friendly production of hydrogen but also effective storage is very important. Underground hydrogen storage technology is a technology that has evolved from the technology for storing natural gas underground, and includes waste gas fields, salt domes, aquifers, and rock cavities. When stored underground, hydrogen is converted into high-pressure gaseous hydrogen, liquefied hydrogen, and ammonia. Liquefied hydrogen requires extremely low storage temperatures, and ammonia is a toxic substance that requires separate handling, and energy loss occurs during the conversion process. To compensate for this, research on liquefied hydrogen, such as multilayer insulation technology, is being conducted. Ammonia has successfully extracted high-purity hydrogen by developing a membrane reactor. Ammonia toxicity can be prevented by strengthening leak detection and blocking facilities. Among these, ammonia was found to be the most suitable for underground storage in terms of economic feasibility, environment, and commercialization.

Enhancing the Performance of Oxide‐Based Transverse Thermoelectric Generators by Optimized Internal Geometry

AbstractIn transverse thermoelectric generators (TTEGs), comprising an artificially anisotropic material formed by a layered and tilted structure of two materials, the induced thermoelectric voltage is generated perpendicular to the applied temperature gradient. The performance of TTEGs composed of alternate layers of La1.99Sr0.01CuO4 (LSCO) and silver (Ag), tilted at an angle φ, with metal‐to‐ceramic thickness ratio νt, is investigated. Improvement in performance is achieved by optimizing the internal geometry parameters, φ and νt of the tilted layered structure. The transverse power factor PFtr and figure‐of‐merit ZtrT of the artificially tilted material composite are analytically calculated and presented in color contours. Experimentally, a power output Pout of 14.5 mW at ΔT = 140 K is measured for a TTEG with φ = 66°, compared to 2.8 mW and 11 mW for generators with φ of 20° and 45°, respectively. Moreover, TTEGs with different values of νt are prepared. Furthermore, transverse multilayer thermoelectric generators (TMLTEG) with output power of 14.3 mW at ΔT = 225 K are fabricated utilizing the ceramic multilayer technology. It is demonstrated that the transverse thermoelectric effect using an artificial anisotropic material consisting of ceramic and metal can be explored for autonomous thermoelectric energy generation for low‐power applications.

3D micromorphological reconstruction and roughness characterization of wood surface based on sequence images

A novel non-contact optical inspection technique is proposed to precisely reconstruct the three-dimensional surface structure of wood and evaluate its roughness. The feasibility of using image fusion techniques to characterize the 3D roughness of wood surfaces is explored by combining high-resolution serial image acquisition techniques with advanced data processing methods. The work focuses on examining various cut surfaces of three distinct wood species: Larch, Catalpa, and Toona sinensis. The proposed 3D roughness parameters are verified using 3D reconstruction and precise measurements. The experimental results demonstrate that the proposed method exhibits strong adaptability in measuring wood surface roughness and achieves a high degree of consistency with the results obtained from traditional digital microscope systems. This study not only validates the possible use of multilayer sequence image fusion technology in measuring wood roughness, but also establishes a solid basis for the creation of 3D assessment criteria for wood surface roughness and associated inspection systems.

Economic Erosion: Examining Germany's Decline as a Business Destination

This study delves into the complex web of causes that have contributed to Germany's gradual decline as a sought-after business location. This scholarly work methodically examines a variety of internal and external variables shaping the country's economic environment, thus providing a comprehensive picture of the significant challenges currently faced by the German economy. The study methodically analyzes key variables such as labor market dynamics, regulatory frameworks, demographic changes and infrastructure improvements to uncover the root causes of this decline. The results of this research are of enormous importance for the formulation of strategic, precise policy initiatives aimed at revitalizing the German economy, strengthening its resilience and restoring its position as a global beacon for industry recruitment and retention. Using a strong mixed methods approach, this study leverage the synergy of primary data collected through surveys, interviews and case studies, and secondary data derived from government reports, academic publications and economic indicators. This multi-layered technology makes it easier to recognize observable patterns and develop concrete, realistic plans that will lead Germany to long-term economic development and prosperity. This research is a component of efforts to revitalize Germany's economic strength and restore its reputation as a leading commercial center, and provides useful information for policymakers, industry executives and academics alike. The comprehensive analysis presented in this study has far-reaching implications for the larger European economic environment and contributes to the global discourse on sustainable economic development and renewal

Design and Performance Analysis of Compact Printed Ridge Gap Waveguide Phase Shifters for Millimeter-Wave Systems.

This paper introduces compact Printed Ridge Gap Waveguide (PRGW) phase shifters tailored for millimeter-wave applications, with a focus on achieving wide operating bandwidth, and improved matching and phase balance compared to single-layer technology. This study proposes a unique approach to achieve the required phase shift in PRGW technology, which has not been previously explored. This study also introduces a novel analytical approach to calculate the cutoff frequency and propagation constant of the PRGW structure, a method not previously addressed. Furthermore, the utilization of multi-layer PRGW technology enables the realization of multi-layer beamforming networks without crossing, thereby supporting wideband operation in a compact size. The proposed design procedure enables the realization of various phase shift values ranging from 0∘ to 135∘ over a broad frequency bandwidth centered at 30 GHz. A 45-degree phase shifter is fabricated and tested, demonstrating a 10 GHz bandwidth (approximately 33% fractional bandwidth) from 25 GHz to 35 GHz. Throughout the operating bandwidth, the phase balance remains within 45 ± 5∘, with a deep matching level of -20 dB. The proposed phase shifter exhibits desirable characteristics, such as compactness, low loss, and low dispersion, making it a suitable choice for millimeter-wave applications, including beyond 5G (B5G) and 6G wireless communications.

Multilayer UWB bandpass filter using liquid crystal polymer technology

This proposed design presents a novel bandpass filter employing a Marchand balun to attain ultra-wideband (UWB) performance extending from 3.1 to 10.7 GHz with 6.8 GHz central frequency and 110% FBW. The UWB bandpass filter’s fractional bandwidth can be tailored owing to the diverse input/output impedances of the planar Marchand balun. This adaptability is accomplished by connecting two planar Marchand baluns consecutively, leveraging the concepts of transversal filter ideas and multilayer LCP technology resulting in 0.3 dB and 12 dB insertion and return losses respectively. In-depth guidelines for the formulation and synthesis of the UWB bandpass filter are incorporated.

Fabrication framework for metal supported solid oxide cells via tape casting

Among the different solid oxide cells (SOCs) designs, metal supported SOCs (MSOCs) offer important advantages such as enhanced mechanical robustness, improved thermal resilience and lower material costs. The conventional tape casting method, which is used for the commercial multilayer ceramic technology, is also attractive for the fabrication of MSOCs due to its inherent scalability and cost-efficient fabrication methodology while offering a reliable product without compromising critical microstructural aspects and electrochemical performance during operation.This study is aimed at addressing the main challenges in the fabrication of MSOCs using tape casting, to provide a robust framework for the fabrication parameters, allowing the technology to advance to a more mature stage. It was shown that the dispersion of the powder particles and the physical and chemical characteristics of the binder are found to play a crucial role in obtaining defect free MSOCs and are discussed in detail. Different architectural designs of the cells (asymmetric and symmetric) and electrode configurations (ceramic and metal-ceramic composites) are studied, highlighting their strengths and challenges. The framework established within this work allowed to fabricate, reproduce and test MSOC that exhibited electrochemical performance comparable to state-of-the-art solid oxide cells (electrolysis current density of 0.6 A/cm2 at 1.3 V at 700oC, 50 % steam in H2 at fuel side and air at the oxygen side).

Materials and manufacturing technology for high reliability rigid-flex multilayer PCB for space 3D-electronics packaging

Rigid-flex Multilayer PCB Technology enables the elimination of several connectors and bulky harness for interconnecting functional electronic systems. This minimizes packaging complexity and reduces performance degradation at high frequencies with an added advantage of reduced weight and volume in high-reliability space electronic packages. Here, only thermo-mechanically stable adhesiveless all polyimide flexible laminate cores and no-flow glass-polyimide prepregs are employed. To overcome the manufacturing issues like registration, coverlay protrusion into the rigid portions, and residual copper deposition at the intersections of flexible and rigid portions; a novel manufacturing process technology is proposed here. The technology has been successfully devised after choosing the most appropriate flexible, rigid, and low-flow prepreg materials. Herein, for the realization of rigid-flex multilayer PCB technology with 2-layers of flex and 8-layers of rigid to meet the functional requirements of the board is presented. The critical registration issues associated with the dissimilar rigid and flexible substrates are successfully addressed to achieve best-fit registration and obtain minimum annular rings of 50 μm in all the inner layers for high reliability. Experimental results manifest that incorporating rigid-flex multilayer PCB technology dramatically reduces weight (>30%) and volume (∼40%) to high-reliability space electronics 3D packaging for static and dynamic applications.

Effect of Reaction Layers on Internal Stresses in Co‐Fired Multilayers of Calcium Manganate and Calcium Cobaltite

A widespread recovery of waste heat requires a cost‐effective production of thermoelectric generators. Thermoelectric oxides are predestined for use at high temperatures. For manufacturing reasons, a multilayer generator design will be easily scalable and cost‐effective. To evaluate the potential of ceramic multilayer technology for that purpose, a multilayer of the promising thermoelectric oxides calcium cobaltite (Ca3Co4O9), calcium manganate (CMO, CaMnO3), and glass–ceramic insulation layers is fabricated. Cracks and reaction layers at the interfaces are observed in the microstructure. The compositions of these reaction layers are identified by energy‐dispersive X‐ray spectroscopy and X‐ray diffraction. Mechanical and thermal properties of all layers are compiled from literature or determined by purposeful sample preparation and testing. Based on this data set, the internal stresses in the multilayer after co‐firing are calculated numerically. It is shown that tensile stresses in the range of 50 MPa occur in the CMO layers. The reaction layers have only a minor influence on the level of these residual stresses. Herein, it is proven that the material system is basically suitable for multilayer generator production, but that the co‐firing process and the layer structure must be adapted to improve densification and reduce the tensile stresses in the CMO.

Studying the Effectiveness of Shaped Charge Jets Created by Graphene-containing Shaped Charge Liners

The paper presents selected results of studies conducted within the framework of the following research project: “Use of graphene and new multilayer explosive technologies in materials for shaped charge liners" (The National Centre for Research and Development in Poland: project No: DOB-BI08/03/01/2016). This study was performed by a consortium made up of the following entities: Institute of Precision Mechanics, Military University of Technology and the Mototechnika company (Poland). The main objective of the performed experiments was to test the effectiveness of shaped charge liners produced with the use of powder metallurgy methods, from mixtures containing copper powder and graphene-coated copper powder. The content of the latter equaled 0%, 1%, 5% and 10%, respectively. Shaped charge jets created with the use of liners made from the powder mixtures tested were recorded with the help of X-ray technology. Firing tests were conducted against steel barriers and the depth of penetration was determined. The obtained results showed that the addition of graphene powder to pure copper powder practically does not increase the depth of penetration of the shaped charge jet compared to scenarios in which sintered liners without this additive were used.

Flexural Strength of Translucent Zirconia Materials Produced with Different Multilayer Technologies: An In Vitro Study.

To evaluate the flexural strength of two translucent multilayered zirconia materials produced with different multilayer technologies. Methodology. Eighty bar-shaped zirconia specimens were prepared from two different multilayered zirconia materials (IPS e.max® ZirCAD Prime and KATANA™ Multilayered Zirconia HTML) and divided into eight groups (n = 10) based on the materials used and the individual layers of the disc for each material: Dentin Prime, Transition Prime, Translucent Prime, Multilayered Prime, Dentin HTML, Transition HTML, Translucent HTML, and Multilayered HTML. The bar-shaped zirconia specimens were cut to include all the layers from translucent to dentin In Multilayered Prime and Multilayered HTML groups. All specimens were fully sintered after cutting from multilayered zirconia discs and subjected to three-point flexural strength test using the universal testing machine. The specimens made of HTML zirconia material showed significantly (P < 0.001) higher flexural strength than those made of IPS e.max® ZirCAD Prime material, with no significant difference (P > 0.05) compared to the specimens in the Dentin Prime group. The Dentin Prime specimens had the highest flexural strength (743 ± 116 MPa) compared to those in the Translucent Prime (514 ± 120 MPa), Transition Prime (575 ± 102 MPa), and Multilayered Prime (531 ± 132 MPa) groups. The flexural strength of the specimens from the individual layers of HTML zirconia material was not significantly different (P > 0.05) among the Dentin HTML (763 ± 56 MPa), Translucent HTML (791 ± 106 MPa), Transition HTML (816 ± 85 MPa), and Multilayered HTML (793 ± 102 MPa) groups. Multilayered zirconia materials produced with different yttria contents by layer have lower flexural strength than those produced with gradient shade technology and the same yttria content for each layer. Therefore, various factors such as the type of prostheses, nesting strategies of prostheses within the zirconia disc, and the desired aesthetical requirements should be considered when selecting the multilayered zirconia materials.

Single-step precision programming of decoupled multiresponsive soft millirobots

Stimuli-responsive soft robots offer new capabilities for the fields of medical and rehabilitation robotics, artificial intelligence, and soft electronics. Precisely programming the shape morphing and decoupling the multiresponsiveness of such robots is crucial to enable them with ample degrees of freedom and multifunctionality, while ensuring high fabrication accuracy. However, current designs featuring coupled multiresponsiveness or intricate assembly processes face limitations in executing complex transformations and suffer from a lack of precision. Therefore, we propose a one-stepped strategy to program multistep shape-morphing soft millirobots (MSSMs) in response to decoupled environmental stimuli. Our approach involves employing a multilayered elastomer and laser scanning technology to selectively process the structure of MSSMs, achieving a minimum machining precision of 30 μm. The resulting MSSMs are capable of imitating the shape morphing of plants and hand gestures and resemble kirigami, pop-up, and bistable structures. The decoupled multistimuli responsiveness of the MSSMs allows them to conduct shape morphing during locomotion, perform logic circuit control, and remotely repair circuits in response to humidity, temperature, and magnetic field. This strategy presents a paradigm for the effective design and fabrication of untethered soft miniature robots with physical intelligence, advancing the decoupled multiresponsive materials through modular tailoring of robotic body structures and properties to suit specific applications.

Serpentine spring design technique for high sensitivity MEMS capacitive accelerometer fabricated by gold multi-layer metal technology

This paper describes a design technique for serpentine spring with the edge span beam L/2. In order to improve design accuracy, we investigate the key structure parameters influenced by the fabrication process for MEMS device, comparing finite element analysis (FEA) and analytical models. It is found that the Fedder model as the analytical model is suitable for the spring constant characteristics of FEA with the edge span beam L/2. Further, the thickness and width are found to be the key structure parameters and the dominant factor of variation regarding the serpentine spring. Based on the analysis, we propose a spring design technique. The experimental results show that the variation between the measured data of 4.46 N m−1 and the design value of 4.15 N m−1 was 7.5%, satisfying the target of ±10%. It is confirmed that the proposed technique can establish the serpentine spring for high sensitivity gold proof-mass MEMS accelerometers.

A Low-profile Dual-band Dual-polarization Co-aperture Array Antenna with High Isolation

This paper proposes a low-profile high-isolation dual-polarization array antenna operating in the L/S band. The radiating unit of the array antenna adopts U-shaped bending dipoles to realize the staggered arrangement of high- and low-band units, and is connected to the feeding network by a coaxial cable. To achieve the non-influence of high-band and low-band feed networks, multi-layer printing technology is used and grooves are etched on the metal plate. In order to reduce the coupling of the high- and low-band dipoles at low frequency, a bandpass filter is added to the high-band feed network, which greatly improves the isolation at low-frequency. The measured results show that the impedance bandwidth of the array is 4.5% (0.971-1.015 GHz) and 7.5% (1.89-2.04 GHz), with gains of 15 and 19 dBi at 1 GHz and 2 GHz, respectively. And the isolation between the dual-polarized ports more than 50 dB and 35 dB was achieved at 1 GHz and 2 GHz, respectively. The proposed array will have practical value in L/S band full-duplex wireless communication systems.

Ceramic Embedding of SiC-Semiconductor Using Cofiring Technology

The presented work demonstrates our current state in embedding of SiC power electronic dies using Ceramic Multilayer Technology. The novelty of the approach presented includes the cofiring of a semiconductor element with ceramic base material, which demands for a reduced sintering temperature of ceramics (using LTCC or ULTCC based ceramics) in combination with an increased temperature stability of the semiconductor.

New input circuits used for parameters determination of circuit breaker voltage and current paths

In the article new constructions of voltage and current transducers have been presented that are used for parameters determination of current and voltage signals in the line protected by circuit breaker. These transducers are used with protection relay that is also a subsystem of source data acquisition for multi-criteria method of circuit breaker diagnosis. Because of the multifunctionality of the device the transducers have to work with, they have to be very accurate, have wide bandwidth and be stable over varying environment conditions like temperature and humidity. As current transducers, Rogowski coils have been described. They have been made with the use of multilayer PCB technology to achieve very high repeatability of coils parameters, low labor costs as well as high bandwidth and excellent linearity. The designs of Rogowski coils have been presented together with measurement results. As voltage transducers, new constructions of reactance transducers, resistive transducers and air core transformers have been presented. The main design effort has been put into achieving wide bandwidth and good linearity. In the paper input circuits adapted to new types of voltage transducers have been described as well as measurement results.

Multilayer Technology for T-die and Feed block

Multilayer Technology for T-die and Feed block

Review of: "Dielectrics and new materials that are well understood for use with this technology. Nano supercapacitors developed with multi-layer nanostructure technology are inherently solid and show excellent mechanical and thermal properties"

Review of: "Dielectrics and new materials that are well understood for use with this technology. Nano supercapacitors developed with multi-layer nanostructure technology are inherently solid and show excellent mechanical and thermal properties"

Review of: "Nano supercapacitors developed with multi-layer nanostructure technology are inherently solid and show excellent mechanical and thermal properties"

Review of: "Nano supercapacitors developed with multi-layer nanostructure technology are inherently solid and show excellent mechanical and thermal properties"

Grid-patterned trench insulated gate bipolar transistor for 1.2 kV hybrid/plug-in hybrid electric vehicle silicon power devices

This paper reports on the newly developed silicon insulated gate bipolar transistor (IGBT) for Toyota’s fifth generation power devices. The designed IGBTs with a grid-patterned trench provide a lower on-state voltage (V ON ) while maintaining a wide mesa width. A successful 15% reduction of V ON was accomplished by enhancement of the two-dimensional hole storage effect. Furthermore, the grid-patterned trench IGBT merged with Schottky and multi-layered anode technology demonstrated a significant improvement in the trade-off curve between the reverse recovery current (I rr ) and V ON in a reverse conducting IGBT without a lifetime control process. As a result, the grid-patterned trench IGBT has contributed to reduce power loss and volume in the new power control units.