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Spatially resolved oxidation of nanocrystalline silicon surfaces has been studied using Fourier Fourier-transformed infrared microscopy. At the same time, photoluminescence (PL) quenching has been recorded. Both characteristics are related to the increase of silicon oxide species on the sample surfaces. Illumination of surfaces by blue light increases oxidation rates and speeds PL quenching in the form of a stretched exponential function. A possible explanation of this behavior considering quantum dots and quantum wires present in the material is proposed.

This study centers on the analysis of a scale-dependent microplate configuration characterized by a porous core enveloped by nanocomposite patches embedded with graphene nanoplatelets. The microplate’s behavior is explored within a humid environment to comprehend the effects of moisture variations on its dynamic performance. Additionally, the microplate rests upon a Kerr foundation, a three-parameter elastic substrate. The material properties of all three layers are contingent upon thickness. To enhance precision, an innovative quasi-three-dimensional shear and normal trigonometric theory is employed, elucidating the kinematic interrelations of the microstructure. Notably, this novel theory accommodates the presence of transverse normal strain. For a comprehensive analysis of size influences, the modified couple stress theory is harnessed. This theory integrates a material length-scale parameter to anticipate outcomes at the micro-scale. By invoking Hamilton’s principle, differential motion equations are deduced and subsequently solved analytically. The investigation centers on probing the consequences of varied parameters on the natural frequencies. The findings underscore that the incorporation of GPLs amplifies the microplate’s stiffness, thus elevating its natural frequencies. In contrast, an escalation in the porosity index leads to a reduction in natural frequencies.

Latent fingerprint (LF) visualization remains a critical and challenging technique in criminal investigations, security surveillance, and forensic science, primarily due to limitations in sensitivity, contrast, and reliability. Polyhedral oligomeric silsesquioxanes (POSS)-based materials have promoted this field by leveraging their nanoscale architecture, customizable fluorescence properties, and exceptional photostability. This review paper has provided a comprehensive analysis of the structural characteristics and functionalized strategies of POSS, which emphasized their integration with organosilicon fluorescent materials for high-performance fingerprint visualization. Furthermore, the potential application of POSS composites, including enhanced detection sensitivity, substrate adaptability, and environmental resilience, has been systematically explored. Finally, this review paper has highlighted future research directions, such as improving material sustainability, optimizing cost-effectiveness, and fostering interdisciplinary innovation, which has bridged laboratory advances with practical forensic applications.

Bone scaffolds are porous structures that are used to repair, regenerate and restore the functions of damaged bone tissue. Scaffolds should have sufficient mechanical strength since they are subjected to different mechanical loadings as implanted in the defect site. Recently, there has been growing interest in the application of micromechanical approaches to estimate the effective mechanical properties of these structures. However, most of the micromechanical methods are originally proposed for dilute concentration condition in which all of the pores are isolated and they are not suitable for the structures like scaffolds with an interconnected network of pores. This paper presents the modified version of the Mori–Tanaka approach which is able to consider the interconnectivity between the pores and is completely appropriate for investigation of the mechanical behavior of the scaffolds. The validity of the developed relations is investigated via statistical finite element analysis. The effective moduli of the numerous scaffolds available in the literature are also computed using the suggested modifications. Comparison between the findings of this paper and published empirical studies shows that for the scaffolds with interconnected pore networks, using these modifications significantly improves the results in comparison with the case of using the classical Mori–Tanaka scheme.

Dk values at the diffusion of CO₂ through microporous PTFE of 1 to 7 × 10^-7cm²s^-1 in the concentration range from 4 × 10^-4 to 0.22 g/l CO₂ are determined using a simple, fast and reliable potentiometric method. The method is based on the least-squares fitting of the potential versus time response of a self made CO₂ sensitive Severinghaus type sensor with PTFE as a gas-permeable membrane. The obtained results are in good agreement with other reported literature data, both experimental or calculated ones using molecular dynamics simulations. The proposed technique is very sensitive especially at low concentrations of gas and may be used for the study of other polymeric membranes too.

In this paper, the authors present the electrostrictive energy conversion ability of cellular electrets after the high-voltage corona polarization. Moreover, the electrostrictive effect of such foamed polymer before and after corona polarization has also been compared and discussed. The enhancement of electrostrictive effect of cellular electrets after corona polarization was observed. In particular, the impact on the electrostrictive effect of the macroscopic electric dipoles inside of cellular polymer which are generated by high-voltage corona poling procedure has been investigated. The present research has promoted the development of the application of electret in the field of energy conversion, actuator, transducers, etc.

We report the reflectivity of one-dimensional finite and semi-infinite photonic crystals, computed through the coupling to Bloch modes (BM) and through a transfer matrix method (TMM), and their comparison to the experimental spectral line shapes of porous silicon (PS) multilayer structures. Both methods reproduce a forbidden photonic bandgap (PBG), but slowly-converging oscillations are observed in the TMM as the number of layers increases to infinity, while a smooth converged behavior is presented with BM. The experimental reflectivity spectra is in good agreement with the TMM results for multilayer structures with a small number of periods. However, for structures with large amount of periods, the measured spectral line shapes exhibit better agreement with the smooth behavior predicted by BM.

The spectacular properties of liquid helium at low temperature are generally accepted as the signature of the bosonic nature of this system. Particularly the superfluid phase is identified with a Bose–Einstein condensed fluid. However, the relationship between the superfluidity and the Bose–Einstein condensation is still largely unknown. Studying a perturbed liquid ⁴He system would provide information on the relationship between the two phenomena. Liquid ⁴He confined in porous media provides an excellent example of a boson system submitted to disorder and finite-size effects.

Much care should be paid to the sample preparation, particularly the confining condition should be defined quantitatively. To achieve homogeneous confinement conditions, firstly a suitable porous sample should be selected, the experiments should then be conducted at a lower pressure than the saturated vapor pressure of bulk helium.

Several interesting effects have been shown in confined ⁴He samples prepared as described above. Particularly we report the observation of the separation of the superfluid-normal fluid transition temperature, T_c, from the temperature at which the Bose–Einstein condensation is believed to start, T_BEC, the existence of metastable densities for the confined liquid accessible to the bulk system as a short-lived metastable state only and strong clues for a finite lifetime of the elementary excitations at temperatures as low as 0.4 K.

Porous Mg alloys will be promising orthopedic implants materials. In this study, porous Mg–Zn alloy with a porosity of 30% was prepared by powder metallurgy process. XRD was used to examine the composition of the sample and synchrotron radiation-based X-ray micro-computed tomography (SR-μCT) was used to investigate the pore properties of the sample. The results showed that the sample comprised a single Mg phase and a Mg₂Zn₁₁ phase. The SR-μCT results showed that the porosity of the sample is about 30% which is approximate to the theoretical porosity. The pore morphology was irregular and the largest pore was about 200 μm in diameter. And a large pore cluster was identified meaning that most of the pores in the sample were interconnected with each other. This is beneficial for the materials transformation after the implantation of the sample in human body, which will boost the bone regeneration. Drug-loading experiment showed that Ibuprofen can be successfully loaded in porous Mg–Zn alloy, which means that porous Mg–Zn alloy could be an orthopedic drug delivery system (DDS).

The paper aims to obtain the cushion curves of a polymer foam commonly used in the protective packaging of fragile products and its fractal cushioning performance. First, the impact curves are obtained to evaluate the dropping damage of a critical component considering a fractal nonlinear dynamic packaging system model, more specifically a fractal cubic-quintic-heptic Duffing’s equation. Then, the two-scale fractal derivative transform is introduced to determine the packaging material fractal behavior due to the material molecular structure. The findings explain the dynamic response behavior of the porous cushion material, and the proposed fractal dynamic model sheds new light on the design and analysis of cushioning packaging systems.

With the increasing demand for energy, heat and mass transfer through porous media has been widely studied. To achieve accuracy in studying the behavior of heat transfer, a good knowledge of the effective thermal conductivity (ETC) of porous materials is needed. Because pore structure dominates the ETC of porous materials and effective stress leads to a change in pore structure, effective stress is one of the key influencing factors affecting ETC. In this study, considering the structure of surface roughness and pore size, based on fractal theory, a novel analytical solution at the pore scale for ETC of porous materials under stress conditions is proposed. Furthermore, in this model, capillaries in porous materials saturated with multiple phases have sinusoidal periodically constricted boundaries. The derived ETC model is validated against available experimental data. Moreover, the influences of the effective stress, initial effective porosity, roughness structure characterization, and wetting phase saturation on the ETC are analyzed. Compared with previous models, the rough surfaces of porous materials and the coupling of heat conduction and mechanics are taken into consideration to make the model more reasonable. As a result, this ETC model can better reveal the mechanism of heat conduction in porous media under stress conditions.

Electrophoretic deposition (EPD) is a good method in the fabrication of the coating materials. Its processing parameters are easy to be operate. It is a nonbeeline process and can be used in the deposition on complex shape and porous surface. It has been widely used in many ways. This paper reviews the principles and fabrication steps of EPD and points out the influencing factors. The developments of EPD in the fabrication of materials, such as solid surface coatings, porous structure materials and gradient materials, are introduced in detail. The future of the application of EPD is also discussed.

This paper describes a new method for surface-alloying treatment to strengthen the pore walls of Al foams using the powder metallurgy method. The advantage of this technique is that the pore walls of Al foams can be enhanced efficiently during the process of preparation. Spherical carbamide particles coated with bronze powder were employed as space-holder. The pore configuration depends mainly on the distribution of space-holder particles during the cold compacted process. The phase components of the modified Al foams were studied by X-ray diffraction Rietveld refinement. Results show that the strengthening effect on the mechanical property of Al foams is significantly related to both phase compositions and phase grain size among the pore walls.

Flower-shaped self-assembled zinc oxide (ZnO) nanoflakes were successfully synthesized via a temperature-controlled hydrothermal method. The crystallinity and phase formation of the compound were determined from powder X-ray diffraction (PXRD) result. Surface morphology investigations reveal the self-assembled ZnO nanoflakes to form a spherical flower-like structure. In addition, the particle size was determined from high-resolution transmission electron microscope measurement as 18nm which is in accord with XRD and UV results. X-ray photo electron spectroscopy studies reveal the chemical composition and oxidation state of the ZnO nanoparticle. The specific surface area was calculated, and mesoporous nature was confirmed using Brunauer–Emmett–Teller analysis. Results support the superior interaction between the electrode and electrolyte ions through surface pores. Capacitive performance of the ZnO electrode material was determined using cyclic voltammetry and galvanostatic charge/discharge studies, and a maximum specific capacitance of 322F/g was obtained at 5mV/sec. Electrochemical impedance spectrum reveals the materials fast charge transfer kinetics.

A GTN-like model which yield function explicitly depends upon the third stress invariant is first described in this paper. Subsequently, a fully implicit stress integration procedure of this constitutive model based on the return-mapping algorithm is developed. The validity and the performance of the implementation of the considered algorithm within a finite element code are checked through simulations of single element test and three-element test under hydrostatic tensile conditions and simple shear loading as well. Afterwards, as a numerical example, the presented constitutive model and, for the purpose of comparison, the GTN isotropic hardening model, are used to analyze the classical tensile test of axisymmetric notched specimens. The obtained results highlight similarities, good agreement between both models as long as failure initiation of specimen is not reached, and discrepancy as soon as failure of specimen starts.

A micromechanics-based elastoplastic constitutive model for porous materials is proposed. With an assumption of modified three-dimensional Ramberg–Osgood equation for the compressible matrix material, the variational principle based on a linear comparison composite is applied to study the effective mechanical properties of the porous materials. Analytical expressions of elastoplastic constitutive relations are derived by means of micromechanics principles and homogenization procedures. It is demonstrated that the derived expressions do not involve any additional material constants to be fitted with experimental data. The model can be useful in the prediction of mechanical properties of elastoplastic porous solids.

By semi-analytical modifications to Mackenzie’s equation, a new third-order relation between bulk modulus and porosity is developed for porous materials. Compared with Mackenzie’s equation, the proposed equation takes into consideration critical porosity and real geometry represented by the assembly of hollow spheres. It has been shown that the proposed equation is in better agreement with 10 sets of published data than Mackenzie’s equation and that has an advantage in predicting the matrix bulk modulus even lack of the data of dense porous specimens. In addition, the proposed equation can describe the bulk modulus of porous materials with critical porosity well. However, Mackenzie’s equation cannot work.

Three-dimensional (3D) Cd–MoS₂ monolith was fabricated at room temperature using 2D MoS₂ nanoflakes as precursor and Cd${}^{2+}$ cations through an interaction between the S atoms on the surface of the MoS₂ nanoflakes and the Cd${}^{2+}$ cations. Then, the Cd–MoS₂ was measured by various techniques. The measurement results show that, to some extent, the Cd–MoS₂ structure is still amorphous like that of the MoS₂ nanoflakes, and it is also a kind of mesoporous material with a mean diameter of 15.70nm and specific surface area of 22.01m²/g. The adsorption results of Rhodamine B and Cu${}^{2+}$ solutions demonstrate that such material exhibits relatively strong adsorption behaviors and high adsorption capability, and also it can be reused for the adsorption after the adsorbates are taken out.

Polyvinyl alcohol (PVA) was grafted on graphene nanosheets (GN) in the reduction of graphene oxide with hydrazine hydrate. The obtained GN-PVA (GP) suspension was treated with the freezing–thawing cycle to fabricate 3D porous monolithic GP materials, which were modified with carbon disulfide to introduce xanthan groups on the wall of porous materials, marked as GPCs. The characterization of GPCs confirmed that PVA was attached on the surface of GNs, and xanthan groups were effectively functionalized on the porous structures, which were composed of randomly oriented GNs. The Pb${}^{2+}$ adsorption pattern for GPC materials was investigated. The kinetic adsorption and isotherm data fit the pseudo second-order kinetic and the Langmuir isotherm models, respectively. The maximum adsorption capacity of Pb${}^{2+}$ reached 242.7mg/g. And GPCs for Pb${}^{2+}$ adsorption could be regenerated with ethylenediamine tetracetic acid (EDTA) solution for repetitious adsorption.

The development of efficient magnetic adsorbents is highly desirable for water treatment. In this work, MnFe₂O₄ and Fe₃O₄ were prepared by a lignosulfonate-assisted hydrothermal method. The structure, surface property and adsorption capacity of the products were investigated. The obtained products have a small amount of carbonaceous materials, mesoporous structure and narrow pore size distribution. In comparison with the samples prepared without lignosulfonate, they have more surface hydroxyl groups and highly negatively charged surface in aqueous solution, which favor the adsorption of cations. Fe₃O₄ and especially MnFe₂O₄ exhibited high adsorption capacity towards Pb(II). The maximal removal efficiency of Pb(II) (50mgL${}^{-1}$) on MnFe₂O₄ was 100% at pH 6.2. The results demonstrate that this method is promising for the synthesis of magnetic adsorbent.