Physical Parameters Of Structure Research Articles

A novel approach for using submerged structure as wave-trapping zone

Entrapment of waves is a hydrodynamic phenomenon that occurs under certain incident wave circumstances. The present article, based on potential flow theory, deals with the phenomena of waves interacting with a proposed submerged structure. Focus of this study is on the frequencies for which the wave trapping occurs in the region of the proposed structure. The frequencies presented correspond to significantly higher values of velocity potential in the region. We refer this region as a wave-trapping zone. In scattering problem the reflection coefficient is also investigated with respect to submergence depth, water depth, length and rigidity of the structure and other physical parameters. The optimum values of the structural parameters are also proposed for zero transmission and trapping frequencies. The investigation establishes that for a suitable configuration we can achieve a range of frequencies for which such a geometry can be used as breakwater with total reflection and at certain frequencies also for trapping of waves.

Multifiller-based polymer composites for shielding high energy ionising radiation.

Polydimethyl silicone rubber-based polymer composites filled with molybdenum and bismuth were fabricated using simple open mold cast technique. The physical and chemical structure and gamma shielding parameters like attenuation coefficient, half-value layer (HVL) thickness and relaxation length have been investigated for the said novel materials using X-ray diffraction (XRD), Fourier transform Infrared spectroscopy (FTIR) and gamma ray spectrometer. XRD study reveals the crystalline nature of the composites. It is evident from FTIR studies that there is no chemical interaction between the polymer matrix and filler particles. The results of attenuation studies reveal that the linear attenuation coefficient increases with addition of Bi and Mo and is found to be 0.653, 1.341 and 1.017, 1.793 and 0.102, 0.152cm-1 for 1MMB and 2MMB polymer composites at 80, 356 and 662keV gamma rays, respectively. The HVL thickness of the materials is found to be 1.06, 0.51 and 0.68, 0.38 and 6.73, 4.532cm for 1MMB (20Mo+10Bi phr) and 2MMB (40Mo+20Bi phr) at these energies, respectively. The mass attenuation coefficient of the novel composites 1MMB and 2MMB is found to be higher than the conventional materials like lead and barite for 356keV gamma rays. In addition, the material is found to be light weight and flexible enabling to be molded in required forms, thus being a substitute for the material lead that is known to be heavy and toxic by nature.

A micro-capillary jetting technology for liquid-liquid microdispersion with narrow size distribution

Liquid-liquid microdispersion is one of the key foundations for chemical process intensification. However, liquid-liquid microdispersion at the conditions of high phase ratio and high volume flow rate remains a problem and new microdispersion technology is highly required. Based on the microscale effect of the liquid jet, we developed the micro-capillary jetting technology. It can produce microdroplets (250–500 μm) with narrow size distribution (CV ≈ 10–20 %) in a wide range of physical properties with large capacity and little cost without the restriction of phase ratio. This paper reports the laws of the micro-capillary jetting technology. The liquid-liquid flow patterns and mechanism are studied, and a precise quantitative model to distinguish different jetting patterns is provided for the first time based on the energy analysis in the microscale. Then important factors including physical properties, dispersion mode and structural parameters are investigated. Accordingly, a mathematical model for the prediction of the average droplet size is established and the energy utilization in the jetting dispersion process is calculated.

Design of Magnetic Coupling Mechanism with Different Primary and Secondary Coils for Maximum Output Power

Output power is an important performance metric related to static or quasi-static wireless power transfer (WPT). As an important component of WPT, the electrical parameters of a magnetic coupling mechanism (MCM) are directly related to its output characteristics. Notably, an optimal WPT design is largely based on MCMs using the same primary and secondary coils. However, in some scenarios involving limited space, the physical structure and electrical parameters of the coils cannot be kept completely consistent. Based on the influence of physical parameters on coupling performance and system characteristics, an optimal design method for MCMs using different primary and secondary coils to ensure maximum output power is proposed. The best receiving coil within a limited space that achieves maximum power at a specific location was selected. Experiments were conducted, with the corresponding results verifying the correctness of theoretical and simulation analyses, as well as the effectiveness of the proposed method.

Deep Learning-Based Design Method for Acoustic Metasurface Dual-Feature Fusion.

Existing research in metasurface design was based on trial-and-error high-intensity iterations and requires deep acoustic expertise from the researcher, which severely hampered the development of the metasurface field. Using deep learning enabled the fast and accurate design of hypersurfaces. Based on this, in this paper, an integrated learning approach was first utilized to construct a model of the forward mapping relationship between the hypersurface physical structure parameters and the acoustic field, which was intended to be used for data enhancement. Then a dual-feature fusion model (DFCNN) based on a convolutional neural network was proposed, in which the first feature was the high-dimensional nonlinear features extracted using a data-driven approach, and the second feature was the physical feature information of the acoustic field mined using the model. A convolutional neural network was used for feature fusion. A genetic algorithm was used for network parameter optimization. Finally, generalization ability verification was performed to prove the validity of the network model. The results showed that 90% of the integrated learning models had an error of less than 3 dB between the real and predicted sound field data, and 93% of the DFCNN models could achieve an error of less than 5 dB in the local sound field intensity.

The Parameter Identification of Structure with TMD considering Seismic Soil-Structure Interaction

Parameter identification is of great significance for the postearthquake performance evaluation of structure equipped with tuned mass damper (TMD). However, the soil-structure interaction (SSI) effects have not been considered in the parameter identification of structure with TMD yet, which influence the dynamic characteristics and seismic responses of structures. This paper aims at proposing a framework for identifying the physical parameters of soil-structure-TMD system. Firstly, the accelerated particle swarm optimization (APSO) algorithm is combined with the search space reduction (SSR) method. Then, the frequency response function and transmissibility function are adopted for output-input and input-only cases, respectively, and a simplified mechanical model for soil-structure-TMD system is employed. Next, the measured responses are used to identify the physical parameters of structure with TMD considering SSI effects. Finally, the effectiveness of the proposed identification method is investigated, and the influences of frequency band and noise pollution on the identification performance are discussed. The results show that the proposed strategy can identify the system physical parameters accurately and quickly. It is worth noting that high frequency bands and noise pollution may lead to estimation error, especially for output-only case.

Research on local sound field intensity control technique in metasurface based on deep neural networks.

The use of tunable metasurface technology to realize the underwater tracking function of submarines, which is one of the hotspots and difficulties in submarine design. The structure-to-sound-field metasurface design approach is a highly iterative process based on trial and error. The process is cumbersome and inefficient. Therefore, an inverse design method was proposed based on parallel deep neural networks. The method took the global and local target sound field feature information as input and the metasurface physical structure parameters as output. The deep neural network was trained using a kernel loss function based on a radial basis kernel function, which established an inverse mapping relationship between the desired sound field to the metasurface physical structure parameters. Finally, the sound field intensity modulation at a localized target range was achieved. The results indicated that within the regulated target range, this method achieved an average prediction error of less than 5 dB for 92.9% of the sample data.

Performance improvement of enhancement-mode GaN-based HEMT power devices by employing a vertical gate structure and composite interlayers*

In this work, p-n junction vertical gate (JVG) and polarization junction vertical gate (PVG) structures are for the first time proposed to improve the performance of GaN-based enhancement-mode (E-mode) high electron mobility transistor (HEMT) devices. Compared with the control group featuring the vertical gate structure, a highly improved threshold voltage (V th) and breakdown voltage (BV) are achieved with the assistance of the extended depletion regions formed by inserting single or composite interlayers. The structure dimensions and physical parameters for device interlayers are optimized by TCAD simulation to adjust the spatial electric field distribution and hence improve the device off-state characteristics. The optimal JVG-HEMT device can reach a V th of 3.4 V, a low on-state resistance (R on) of 0.64 mΩ cm2, and a BV of 1245 V, while the PVG-HEMT device exhibits a V th of 3.7 V, an R on of 0.65 mΩ cm2, and a BV of 1184 V, which could be further boosted when an additional field plate design is employed. Thus, the figure-of-merit value of JVG- and PVG-HEMT devices rise to 2.4 and 2.2 GW cm−2, respectively, much higher than that for the VG-HEMT control group (1.0 GW cm−2). This work provides a novel technical approach to realize higher-performance E-mode HEMTs.

Design theory for vibration characterisation experiments on real turbine blades with underplatform damper

One of the main causes of turbine rotor blade failures is high-frequency fatigue caused by blade resonance, and the vibration of turbine blades can be effectively suppressed through the reasonable design of dry friction damping structure. In order to understand the vibration characteristics of the blade-disc system and to check whether the damping effect meets the technical specifications, it is necessary to design and carry out dry friction damping blade vibration characteristics experiment. This paper takes a certain type of underplatform damped turbine blade in production as an example, and briefly describes the design idea and design process of such blade vibration characteristic experiments under the premise of the experiment blade structure, material and other physical parameters.

Effect of Co/Nd co-doping on the structural, optical, and morphological properties of ZnO nanorods grown on silicon substrate Si (100) by hydrothermal method

In this study, single-doped (cobalt (Co), neodymium (Nd)), and co-doped (Co/Nd) ZnO thin films were fabricated through the hydrothermal method on a silicon substrate (100) and investigated structural, morphological, and optical characteristics. In this work, tunable bandgap engineering of single-phase Co/Nd co-doped ZnO nanorods was reported to be controlled through variation of dopant concentrations. The concentration of neodymium varies as 4, 8, and 12 % by weight, while cobalt is fixed up to 4 %. XRD confirms the phase purity and high crystalline nature of the prepared nanorods. The physical structural parameters such as-fabricated nanorods were investigated in detail. Furthermore, Scherrer, Williamson-Hall (W–H), and size-strain plot (SSP) methods were used to investigate the crystallite size and lattice strain. The optical parameters like absorbance (A), transmittance (%T), energy bandgap (Eg), skin depth (δ), optical density (Dopt), optical conductivity (σopt), Urbach energy (Eu), and extinction coefficient (k), were investigated by UV–vis spectra. This study shows that grown films are suitable for modern optoelectronic applications.

Ensuring the Safety of Buildings and Structures Damaged as a Result of Military Man-Made Actions

A significant number of destroyed buildings and structures during the military aggression of the Russian Fed-eration in Ukraine make it necessary for scientific organizations to solve new problems in the restoration of residential and public buildings. After explosive devices have hit the building, the first task is to identify the possibility of its further operation. Technical assessment of the damage level should be justified by using ex-perimental data on changes in the physical and mechanical parameters of construction materials and structures, which are strength, deformability, crack resistance, etc., as a result of the blast waves and fires that accompany explosions in the premises. An urgent task is to develop a methodology that takes into account the impact of explosions and fires caused by them so that structures can be calculated and their residual life estimated. For many decades, the State Research Institute of Building Constructions has been solving problems of assessing the technical condition of damaged buildings and structures as a result of man-made disasters and actions, fol-lowed by the development of technical solutions that ensure the necessary operational characteristics of these objects can be restored.

Development of Poly(sorbitol adipate)-g-poly(ethylene glycol) Mono Methyl Ether-Based Hydrogel Matrices for Model Drug Release.

Hydrogels were prepared by Steglich esterification and by crosslinking pre-synthesized poly(sorbitol adipate)-graft-poly(ethylene glycol) mono methyl ether (PSA-g-mPEG) using different-chain-length-based disuccinyl PEG. PSA and PSA-g-mPEG were investigated for polymer degradation as a function of time at different temperatures. PSA-g-mPEG hydrogels were then evaluated for their most crucial properties of swelling that rendered them suitable for many pharmaceutical and biomedical applications. Hydrogels were also examined for their Sol-Gel content in order to investigate the degree of cross-linking. Physical structural parameters of the hydrogels were theoretically estimated using the modified Flory-Rehner theory to obtain approximate values of polymer volume fraction, the molecular weight between two crosslinks, and the mesh size of the hydrogels. X-ray diffraction was conducted to detect the presence or absence of crystalline regions in the hydrogels. PSA-g-mPEG hydrogels were then extensively examined for higher and lower molecular weight solute release through analysis by fluorescence spectroscopy. Finally, the cytotoxicity of the hydrogels was also investigated using a resazurin reduction assay. Experimental results show that PSA-g-mPEG provides an option as a biocompatible polymer to be used for pharmaceutical applications.

Systematic First-Principles Calculations of Ce3+-Dopant in Garnet-Type Oxide Phosphors

A study of Ce3+-doped oxide phosphors was performed using first-principles calculations based on the relativistic DV-Xα method. In particular, we focused on the Ce3+-doped garnet-type oxides, which have potential applications in solid-state lighting and display devices. The electronic structure and optical properties of the phosphors were analyzed. The energy levels of the Ce3+ ions were affected by the coordination number and the crystal field strength of the surrounding oxygen ions. In addition, the crystal structure of the material had a significant impact on the energy levels of the Ce3+ ions, with different crystal structures leading to different energy levels.The Ce3+ ion is substitutionally incorporated in the garnet lattice, and the 4f electron of Ce3+ plays an important role in the luminescence of the material. The emission wavelengths of the 5d-4f transition energy of Ce3+ can be tailored by varying the crystal structure and the composition. The 5d orbitals of Ce3+ are substantially affected by the crystal field splitting while the amplitude of crystal field splitting (εcfs) is caused by many parameters: coordination number, symmetry of Ce3+ site, and bond lengths between the Ce3+ ion and the oxygen ions (O2-). This study incorporated the following computational conditions: i) lattice relaxation, ii) the choice of the exchange-correlation potential, and iii) Slater’s transition state method. The effects of these conditions were analyzed. In addition, the correlations among physical properties and electronic structure parameters were also investigated in detail.The first-principles calculation results were compared to the experimental data to validate the accuracy of the theoretical models, which showed a good agreement between the experimental and predicted values.

Research on the Effect of Coordinated Remediation of Heavy Metal Pollution in Roadbed Slope Soil by Combining Biochar with Reed

This study investigated the effect of modified activated carbon combined with plants on the coordinated restoration of heavy metal pollution in roadbed slope soil. This study used wheat husks as raw materials, potassium hydroxide and permanganate as modifiers, and aquatic plant reeds to remediate heavy metals in roadbed slope soil. The adsorption amount and removal rate of heavy metals Cu, Pb, and Cr were investigated under adsorbent dosage, adsorbent physical structure parameters, different pH environments, and ternary composite heavy metal body experimental conditions. According to the experimental results, after activation, the total pore volume and total specific surface area of biochar increased significantly, 21.4 and 111.7 times those before activation, respectively. The order of removal rates of heavy metal ions by different adsorbents was Pb > Cr > Cu. When the adsorbent was biochar–reed joint remediation, the maximum adsorption capacity of Cu, Pb, and Cr was 31.25, 136, and 52.3 mg/g. The adsorption capacities of the two adsorbents (biochar and biochar–reed) for Pb were the highest, and the adsorption sensitivity of the adsorbents for Pb was higher than that for Cr and Cu. Under single-component conditions, the adsorption capacity of biochar to heavy metals Cu, Pb, and Cr was ranked as Pb > Cu > Cr. In a ternary solution system, the adsorption capacity of biochar to heavy metals Cu, Pb, and Cr was ranked as Cu > Cr > Pb. Considering the adsorption capacity and removal rate of nutrient-rich substances, as well as the cost and effect of the use of the adsorbent, the recommended amount of the adsorbent was 4–6 g.

Multilevel Encoding Physically Unclonable Functions Based on The Multispecies Structure in Diamonds

AbstractThe multilevel encoding (MLE) scheme is an effective method for improving the anticounterfeiting encryption capabilities of physically unclonable functions (PUFs). However, owing to the correlation between encoding layers, the encoding capacity (EC) is difficult to improve by orders of magnitude. Herein, four noncorrelated structures in the diamond crystal structure (carbon–carbon single bond, defect luminescence structures, spin structures, and electron energy distribution structures) are considered for MLE. First, the microdiamonds containing nitrogen‐vacancy (NV) color centers are embedded into polydimethylsiloxane (PDMS) to fabricate PUFs. Using an optical imaging system, four codable images of four noncorrelated structures are read. The noncorrelation of the four‐level encoding structure is verified by calculating the Hamming distance (0.496 ± 0.02). The results show that EC exponentially improves to 24×10 000/(100 pixels)2. Furthermore, the encoding method based on the energy level does not depend on physical structure parameters, such as the size and position of the spin structure. Thus, it is protected from structural modeling attacks, resulting in high security. Moreover, PUF labels based on PDMS flexible substrates can be employed for various flexible applications. In the proposed scheme, the information is encrypted by a four‐level two‐dimensional (2D) barcode and decoded by self‐developed PUF authentication software. The proposed scheme presents a way for developing next‐generation PUFs with super‐high EC.

Carbon-Doped Co2MnSi Heusler Alloy Microwires with Improved Thermal Characteristics of Magnetization for Multifunctional Applications.

In the current work, we illustrate the effect of adding a small amount of carbon to very common Co2MnSi Heusler alloy-based glass-coated microwires. A significant change in the magnetic and structure structural properties was observed for the new alloy Co2MnSiC compared to the Co2MnSi alloy. Magneto-structural investigations were performed to clarify the main physical parameters, i.e., structural and magnetic parameters, at a wide range of measuring temperatures. The XRD analysis illustrated the well-defined crystalline structure with average grain size (Dg = 29.16 nm) and a uniform cubic structure with A2 type compared to the mixed L21 and B2 cubic structures for Co2MnSi-based glass-coated microwires. The magnetic behavior was investigated at a temperature range of 5 to 300 K and under an applied external magnetic field (50 Oe to 20 kOe). The thermomagnetic behavior of Co2MnSiC glass-coated microwires shows a perfectly stable behavior for a temperature range from 300 K to 5 K. By studying the field cooling (FC) and field heating (FH) magnetization curves at a wide range of applied external magnetic fields, we detected a critical magnetic field (H = 1 kOe) where FC and FH curves have a stable magnetic behavior for the Co2MnSiC sample; such stability was not found in the Co2MnSi sample. We proposed a phenomenal expression to estimate the magnetization thermal stability, ΔM (%), of FC and FH magnetization curves, and the maximum value was detected at the critical magnetic field where ΔM (%) ≈ 98%. The promising magnetic stability of Co2MnSiC glass-coated microwires with temperature is due to the changing of the microstructure induced by the addition of carbon, as the A2-type structure shows a unique stability in response to variation in the temperature and the external magnetic field. In addition, a unique internal mechanical stress was induced during the fabrication process and played a role in controlling magnetic behavior with the temperature and external magnetic field. The obtained results make Co2MnSiC a promising candidate for magnetic sensing devices based on Heusler glass-coated microwires.

Fishbone model-based inversion to estimate physical parameters of elastic structures under earthquake excitations

Fishbone model-based inversion to estimate physical parameters of elastic structures under earthquake excitations

Magneto-structural characterization of different kinds of magnetic nanoparticles

Using well-established measurement techniques like transmission electron microscopy (TEM), dynamic light scattering (DLS), small and wide angle X-ray scattering (SAXS, WAXS), susceptometry, and magnetorelaxometry, the distribution of the physical and magnetic size (magnetic moments) and magnetic anisotropy of a variety of structurally different magnetic nanoparticle samples (MNPs) is analyzed and compared. A term which accounts for the presence of weak magnetic areas (WMAs) within the MNPs was introduced to the widespread analysis model for M(H) data, enabling a consistent interpretation of the data in most of the systems. A comparison of the size distributions as obtained for the physical and the magnetic diameter suggests a multidomain structure for three single core systems under investigation, in all probability evoked by the presence of a wustite phase, as identified by WAXS.Analyzing the relationship d < dm < dc between the average single core diameter d, the effective magnetic (domain) size dm and the cluster diameter dc quantitatively, two qualitatively different magnetic structures in multicore MNP (MCMNP) systems were identified: (i) The magnetic moments of single cores within the MCMNP of fluidMAG tend to build flux closure structures, driven by dipole–dipole interaction. (ii) The magnetic behavior of Resovist® was attributed to the presence of domain sizes of about 12 nm within MCMNP, exceeding the single core diameters of 5 nm. Thereby, WAXS revealed a bimodal crystallite size distribution suggesting a crystallite merging process within the MCMNP. The value of the effective magnetic moment of these MCMNP could be explained within the presented “random moment cluster model” (RMCM).We conclude that the combination of physical and magnetic structure parameters obtained from complementary measurement methods allows a reliable assessment of the magnetic structure of single and multicore MNPs.

Modeling and property study of thermoelectric converter based on subwavelength photothermal absorption structure

Achieving light absorption and conversion in a wide wavelength region and large angles of incidence is an effective way to improve the efficiency of thermoelectric devices. In this work, the thermoelectric converter device with a sub-wavelength photothermal absorption structure is designed, and the thermoelectric device is adapted to medium and high-temperature working environments by introducing PbS and SiGe thermoelectric materials. By changing the material of the surface heat-absorbing layer and studying the adjustment effect of the shape and size of the sub-wavelength photothermal absorption structure on reflectivity, the perfect absorption of sunlight with a wide wavelength region and large angles of incidence is realized, and the maximum photothermal conversion is achieved. Furthermore, the qualitative and quantitative relationships between the thermal absorption and thermoelectric conversion performance of PbS and SiGe thermoelectric materials and the physical parameters of surface subwavelength photothermal absorption structures are studied, so as to maximize the absorption and conversion of thermal energy into electrical energy. This work provides research ideas for the design of perfect thermoelectric devices.

Pore fractal characteristics of fiber-reinforced backfill based on nuclear magnetic resonance

To investigate the pore fractal characteristics of fiber-reinforced backfill, uniaxial compression tests and nuclear magnetic resonance (NMR) tests were conducted on reinforced backfills with different cement-tailing ratios (1:6, 1:8, and 1:10) and different fiber types (polyacrylonitrile fiber and glass fiber). The relationship between the pore size distribution, elastic modulus, uniaxial compressive strength, and cement-tailings ratio of the backfill was investigated, and the pore fractal dimensions of three types were quantified. The results showed that the peak signal amplitude and total spectral peak area of the fiber-reinforced backfill were highest reduced by 21.2% and 25.3%, respectively, compared with that of the fiber-free backfill. The uniaxial compressive strength and elastic modulus of the backfill specimens decreased with decreasing cement-tailings ratio. The micropore fractal dimension values of the backfill specimens ranged from 0.30 to 1.00, while the mesopore and macropore fractal dimension values were in the range of 2.96 to 3.00. The correlation coefficients of the mesopore and macropore fractal dimensions of the backfill are >0.94, and the fractal dimension of mesopores and macropores was not significantly correlated with the cement-tailings ratio and fiber type. The results can provide a reference for discussing the relationship between the microscopic pore structure and macroscopic physical parameters of fiber-reinforced backfill.