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Packaging insulation materials with high thermal conductivity and excellent dielectric properties are favorable to meet the high demand and rapid development of third generation power semiconductors. In this study, we propose to improve the thermal conductivity of epoxy resin (EP) by incorporating a three-dimensional boron nitride thermally conductive network. Detailedly, polyurethane foam (PU) was used as a supporter, and boron nitride nanosheets (BNNSs) were loaded onto the PU supporter through chemical bonding (BNNS@PU). After immersing BNNS@PU into the EP resin, EP-based thermally conductive composites were prepared by vacuum-assisted impregnation. Fourier transform infrared spectrometer and scanning electron microscope were used to characterize the chemical bonding and morphological structure of BNNS@PU, respectively. The content of BNNS in BNNS@PU/EP composites was quantitatively analyzed by TGA. The results show that the thermal conductivity of the BNNS@PU/EP composites reaches 0.521 W/m K with an enhancement rate η of 30.89 at an ultra-low BNNS filler content (5.93 wt. %). Additionally, the BNNS@PU/EP composites have excellent dielectric properties with the frequency range from 101 to 106 Hz. This paper provides an interesting idea for developing high thermal conductivity insulating materials used for power semiconductor packaging. [ABSTRACT FROM AUTHOR]

Over the last two decades, Electron Energy Loss Spectroscopy (EELS) imaging with a scanning transmission electron microscope has emerged as a technique of choice for visualizing complex chemical, electronic, plasmonic, and phononic phenomena in complex materials and structures. The availability of the EELS data necessitates the development of methods to analyze multidimensional data sets with complex spatial and energy structures. Traditionally, the analysis of these data sets has been based on analysis of individual spectra, one at a time, whereas the spatial structure and correlations between individual spatial pixels containing the relevant information of the physics of underpinning processes have generally been ignored and analyzed only via the visualization as 2D maps. Here, we develop a machine learning-based approach and workflows for the analysis of spatial structures in 3D EELS data sets using a combination of dimensionality reduction and multichannel rotationally invariant variational autoencoders. This approach is illustrated for the analysis of both the plasmonic phenomena in a system of nanowires and in the core excitations in functional oxides using low loss and core-loss EELS, respectively. The code developed in this manuscript is open sourced and freely available and provided as a Jupyter notebook for the interested reader. [ABSTRACT FROM AUTHOR]

Low-energy ion beam irradiation, combined with the introduction of impurities, presents a promising approach for nanopatterning silicon (Si) surfaces. In this research, we investigate the surface evolution of Si (100) surfaces irradiated by 75 eV helium (He) plasma, in the presence of tantalum (Ta), traditionally regarded as an impurity incapable of initiating pattern formation, as evidenced in prior studies. The Ta impurities are pre-deposited onto the Si surfaces using the magnetron sputtering method, which offers a more controlled and quantifiable approach compared with the conventional co-deposition route. After irradiation at 800 K, dense cone arrays are produced on the Si surface. The growth of the cones is explored for fluence spanning (1–10) × 1025 m−2. The cross-sectional scanning electron microscope images indicate that the cone lengths and base width are well characterized by t1/2 dependence. The kinetics of the cone growth follow Fick's law, characterized by an effective diffusive mechanism with the coefficients of diffusion: D = 6.49 ± 0.83 × 10−16 m−2 s−1. Transmission electron microscope observations reveal that the cone has distinct inner and outer parts with different microstructures and a clear interface. The growth mechanism of these cones is elucidated as a composite process involving preferential sputtering, the destabilizing influence of He bubbles, and the migration of adatoms. [ABSTRACT FROM AUTHOR]

The scanning electron microscope (SEM) recordings of dynamic nano-electromechanical systems (NEMS) are difficult to analyze due to the noise caused by low frame rate, insufficient resolution, and blurriness induced by applied electric potentials. Here, we develop an image processing platform enhanced by the physics of the underlying system to track the motion of buckling NEMS structures in the presence of high noise levels. The algorithm is composed of an image filter, two data filters, and a nonlinear regression model, which utilizes the expected form of the physical solution. The method was applied to the recordings of a NEMS beam about 150 nm wide, undergoing intra- and inter-well post-buckling states with a transition rate of approximately 0.5 Hz. The algorithm can track the dynamical motion of the NEMS and capture the dependency of deflection amplitude on the compressive force on the beam. With the help of the proposed algorithm, the transition from inter-well to intra-well motion is clearly resolved for buckling NEMS imaged under SEM. [ABSTRACT FROM AUTHOR]

A non-destructive method for detecting sub-micrometer-sized micropipes on an entire wafer surface is investigated. Since it is difficult to detect sub-micrometer-sized micropipes due to their small core size, a non-destructively and accurately detecting method is required. To solve the issue, we focus on a characteristic depression generated around micropipes, namely, line-shaped depressions. In this paper, the location of line-shaped depressions is identified by using optical inspection, and the line-shaped depressions are distinguished whether micropipes exhibit line-shaped depression or not by using mirror electron microscope observation as high-resolution inspection. The accuracy of the distinction results is confirmed by scanning electron microscope observation, and electrical characteristics of the P–N diode are fabricated using the inspected wafer. Furthermore, the sub-micrometer-sized micropipes are observed at the sites of leakage current identified by emission microscopy. Additionally, device simulation of the blocking-voltage characteristics of P–N diodes suggests that the increase in leakage current depends on the electric field at the sub-micrometer-sized micropipes, regardless of their core size. [ABSTRACT FROM AUTHOR]

Gastropods forage with their radula, a thin chitinous membrane with embedded teeth, which scratch across the substrate to lose food particles. During this interaction, the risk of loosening particles is obvious without having a specialized mechanism holding them on the tooth surface. As mucus secretions are essential in molluscan life cycles and the locomotion and attachment gels are known to have an instant high adhesion, we have hypothesized that the saliva could support particle retention during feeding. As adhesion of snail saliva was not studied before, we present here an experimental setup to test its particle-binding capacity using a large land snail (Lissachatina fulica, Stylommatophora, Heterobranchia). This experiment was also applied to the gels produced by the snail foot for comparison and can be potentially applied to various fluids present at a small volume in the future. We found, that the saliva has high particle retention capacity that is comparable to the foot glue of the snail. To gain some insight into the properties of the saliva, we additionally studied it in the scanning electron microscope, estimated its viscosity in a de-wetting experiment, and investigated its elemental composition using energy dispersive X-ray spectroscopy reveling higher contents of Ca, Zn and other potential cross-linkers similar to those found in the glue. [ABSTRACT FROM AUTHOR]

In recent years, precision and accuracy for a more precise critical dimension (CD) control have been required in CD measurement technology. CD distortion between the measurement by a critical dimension scanning electron microscope (CD-SEM) and a reference tool is the most important factor for a more accurate CD measurement. CD bias varies by a CD-SEM and a pattern condition. Therefore, it is urgently needed to identify, characterize, and quantify those parameters that may or may not affect the CD measurement by a CD-SEM. The sensitivity of the Monte Carlo simulated CD-SEM images with multiple physical modeling components has been studied previously. In this study, we demonstrate that the work function and elastic scattering potential models have a significant impact on secondary electron emission intensity, but their influence on the shape of the linescan profile is small, and other factors like the optical energy loss function and dielectric function models have even smaller effects. We have evaluated the uncertainty in the linescan profiles of Si line structures with different sidewall angles due to several different physical factors. It is found that when the CD is evaluated by a peak/valley method, the uncertainty of the CD is negligible. Therefore, it is concluded that the CD value and its related uncertainty are not critically related to the physical factors of the present Monte Carlo simulation model but rely dominantly on the line structure and electron beam parameters. [ABSTRACT FROM AUTHOR]

We report on the metrological characterization of the emission from a germanium-vacancy center in diamond under a microfabricated solid immersion lens in a confocal laser-scanning microscope setup. Ge ions were implanted into a synthetic diamond at 3 MeV, and germanium-vacancy centers were then formed by subsequent annealing. Afterward, solid immersion lenses were fabricated in a focused ion beam scanning electron microscope. The photoluminescence was investigated at room temperature in terms of the spectral distribution, the excited state lifetime, the second-order correlation function, and the saturation behavior, proving simultaneous high single-photon purity and high brightness. Two methods were exploited to minimize the residual multi-photon probability: spectral filtering and temporal filtering. According to these results, we assume that Raman scattered photons and emission from neighboring color centers play an important role in the residual multi-photon emission probability. The system efficiency of the single-photon source was investigated and found to be in accordance with the value calculated from all sources of loss in the setup. The branching ratio of the germanium-vacancy center for the decay into the ground state and into metastable state was calculated. The results enable the usage of the single-photon source in future quantum radiometric experiments. [ABSTRACT FROM AUTHOR]

Because of their full compatibility with CMOS technology, HfO2-based ferroelectrics, and especially Hf0.5Zr0.5O2 (HZO), attract a lot of attention. However, the overwhelming majority of measurement techniques provides only information about the cumulative electrical response of many domains of HZO, i.e., at the macroscopic level. So far, only piezoresponse force microscopy technique was applied to visualize distinct ferroelectric domains in HZO and to analyze the local switching behavior in the microscopic level. This work introduces the possibility of using electron beam-induced current (EBIC) technique in the scanning electron microscope to visualize the gradual polarization reversal of HZO and to obtain the local polarization dynamics. We show that although the local EBIC signal is affected by surrounding domains, studying the variations in the ferroelectric response of individual domains as well as the spread of the local stiffness and local imprint is possible by this method. Besides, we show the connection between the EBIC current and an electric field across passive non-ferroelectric layers at interfaces between HZO and metal electrodes, which opens up additional opportunities to use the EBIC technique for investigations of interface-dependent properties of HZO ferroelectrics in the future. [ABSTRACT FROM AUTHOR]

Phosphoric acid-based geopolymer (PGEO) belongs to acidic material and has many applications in environmental disposal. The curing method has an important impact on the mechanic performance of geopolymers, the existing research concerning PGEO synthesized from fly ash (FA) and phosphoric acid (PA) are performed on the specimens cured at sealed environment, but no related research on the PGEO cured at an open environment is found. Therefore, to investigate the mechanic performance, pH and of PGEO cured in an open environment, the unconfined compressive strength tests were conducted on PGEO specimens cured in an open environment, and its mechanism was investigated using Scanning Electron Microscope, X-Ray diffraction, and Fourier transform infrared reflection (FTIR) tests. Moreover, the thermogravimetric was measured using the thermogravimetric tests. The results showed that in the scope of this study, the compressive strength of the PGEO decreased with the PA concentration and the liquid–solid ratio (L/S) increasing. When the L/S was a fixed value, as the curing time increased, an obvious strength loss was observed for the PGEO with the content of 40 and 50%, but the compressive strength increased first and then, reduced for the PGEO with the content of 40 and 50%, a maximum strength was obtained at 60 days of curing. The open curing for the PGEO is not conducive to the later growth of compressive strength. As the PA concentration and L/S increased, the pH descended. As the curing time lengthened, the pH first raised and then droped, the maximum pH was obtained at 60 days. Furthermore, the compressive strength increased with the pH with a good correlation. The microscopic analysis showed that the crystalline compounds AlSiP3, Ca2P2O7(H2O)2, molecular sieve SAPO-20 (Al0.47Si0.13P0.4)O2, AlPO4-5 (AlPO4), CaHPO4, and AlPO4 in PGEO were detected. Overall, the open curing environment is not conducive to PGEO, and sealed curing should be used in engineering applications. [ABSTRACT FROM AUTHOR]

In this present investigation, novel hybrid magnesium composites were synthesized by the inclusion of self-lubricating (BN/MoS 2) and ceramic (ZrO 2) particulates with the help of the powder metallurgy technique. ZE41 magnesium (Mg–4Zn-1RE-0.7Zr) was applied for a broad range of components, including the gearbox casing, the framework of the door, and transmission in aircraft like the Sikorsky UH-60 and the Boeing 727. Apart from its structural application, its usage was limited because of its deficient wear and mechanical properties. This research focuses on enhancing the potential applications of the ZE41 magnesium alloy by improving its mechanical and tribological characteristics. The design of the experiment scheme was applied to explore the effect of individual reinforcements and their synergistic effects on various properties of prepared composites. Microstructural inspection was employed to inspect the morphological characteristics of prepared specimens through scanning electron microscope (SEM) and Energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction analysis (XRD). By analysing SEM, EDS, and X-ray diffraction patterns, the microstructural evaluation reveals uniform phase dispersion and the existence of reinforcements with some minor defects. As a result of the inclusion of reinforcements in composites, the hardness of the reinforced specimen improved to 39.65%, while the wear rate of the reinforced specimen decreased to 40.90% compared with monolithic alloy. A multi-objective grey relational analysis (GRA) optimization method was used to perform a detailed tribological analysis on Specimen G (ZE41 mg + 3% ZrO 2 + 3% MoS 2). According to the results of GRA, the optimized rate of wear and frictional coefficient were achieved on sliding velocity (4 ms−1), sliding distance (2000 m), and load (10 N). The worn surface micrograph reveals that the reinforced composite underwent abrasion and delamination wear, while the unreinforced alloy experienced plastic deformation. [ABSTRACT FROM AUTHOR]

Silicon carbide fiber reinforced silicon carbide ceramic matrix composite (CMC SiC f /SiC) has the advantages of high temperature resistance, corrosion resistance, high strength, low density, and oxidation resistance. It is a high-performance advanced material in aerospace, energy and other fields. However, due to its high hardness, brittleness and anisotropy of fiber structure, the research on application-oriented high-quality processing technology has become a hot issue. In this paper, a new process of rotational thirteen-beam coupling nanosecond laser processing of CMC-SiC f /SiC was studied. The rotational thirteen-beam coupling ablation experiments were carried out on CMC-SiC f /SiC workpiece. A laser beam is divided into thirteen beams and rotated around the beam center by using a beam splitter element. The morphology, structure and composition of ablation holes at different speeds were observed and analyzed by laser confocal microscope, scanning electron microscope, and X-ray energy dispersive spectrometer. It is found that the characteristics of rotational beam coupling have a significant effect on the laser ablation morphologies. The results show that the ablation region of CMC-SiC f /SiC is elliptical due to the fast heat transfer of fibers. The energy density distribution of the waist section of the Gaussian like beam after beam coupling is similar to the "W" shape, and the central energy is lower than the surrounding energy, and the ablation holes also show a similar "W" shape. With the increase of rotational speed, the hole depth first decreased and then increased, the hole diameter and roundness first increased and then decreased, and the hole section was "W" shaped. The ablation area can be divided into five parts: the white granular SiO 2 solid coverage area, the recast layer, the lower recast layer, the molten layer, and the heat affected zone. The rotational characteristics will make the reaction intensity of the whole ablation area more uniform in the circumferential direction. The formation mechanism and element distribution of each part were explored. The research work in this paper will provide a new technical way for the high-performance application of CMC-SiC f /SiC. [ABSTRACT FROM AUTHOR]

The effectiveness of silicon carbide (SiC) planarization mostly relies on the chemical and mechanical effects during chemical mechanical polishing (CMP). Nevertheless, the alumina (Al 2 O 3) abrasive only provides a mechanical effect and is incapable of achieving a high-efficiency polishing of SiC. To address this issue, a series of novel Al 2 O 3 @MnO 2 composite abrasives were prepared by encapsulating varying amounts of manganese dioxide (MnO 2) on Al 2 O 3 abrasive, and the polishing performance on SiC wafers was evaluated. The X-ray diffraction (XRD) and scanning electron microscope (SEM) images, along with the size and zeta potential data, show that MnO 2 is successfully coated on the surface of Al 2 O 3 , and the dispersion of Al 2 O 3 @MnO 2 composite abrasive is significantly improved when compared with the pure Al 2 O 3. Furthermore, the CMP experiment and surface profile analysis demonstrate that the material removal rate (MRR) can reach a maximum value of 640.47 nm/h when using a 0.05 wt% MnO 2 -coated Al 2 O 3 composite abrasive, which is 76 % higher than that of traditional Al 2 O 3 abrasive. Furthermore, the average surface roughness (Sa, arithmetic mean height) of SiC is reduced to 0.73 nm. X-ray photoelectron spectroscopy results reveal that the surface of SiC is oxidized and forms a chemical bond known as Mn–O–Si after CMP. The results of the friction coefficient test and contact angle test indicate that slurries containing composite abrasive have exceptional wettability and a higher friction coefficient. Under the synergistic chemical and mechanical effects, SiC is oxidized to soft oxide and then removed circularly to reach excellent flatness. [ABSTRACT FROM AUTHOR]

CuS nanostructures with high surface areas were produced through a hydrothermal method using simple materials. These included pure CuS, as well as CuS doped with Fe, Ag, and Mn, as well as dual-doped with Fe/Mn and Ag/Mn. X-ray diffraction (XRD), field-emission scanning electron microscopes (FE-SEM), chemical composition (EDX) analysis, zeta potential, ultraviolet–visible (UV–vis) absorption spectra, and compositional chemicals (FTIR) have been used to characterize the produced nanoparticles. The XRD patterns indicate that the CuS is in hexagonal covellite polycrystalline phases with estimated crystalline sizes of 25.14–14.25 nm. The optical measurements showed that the band gaps ranged from 3.19 to 2.24 eV. The inhibitory effects of pristine CuS, as well as CuS doping with Fe, Ag, and Mn and dual-doping with (Fe/Mn, Ag/Mn), against Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli, were evaluated using the inhibition zone method. All samples exhibited robust antibacterial activity against all strains. The highest level of inhibition against all strains was observed with a concentration of 4 mg/ml of copper sulfide. Out of all the tested samples, (Ag/Mn) dual-doped copper sulfide showed the highest antibacterial activity against both negative-gram and positive-gram bacteria. Hence, (Ag/Mn) dual-doped copper sulfide might be applied as an antibacterial agent with antibiotics to kill and prevent resistance bacterial development. [ABSTRACT FROM AUTHOR]

In this experimental study, we explore the potential enhancements in thermal conductivity while investigating alterations in latent heat and phase change temperature within Composite Phase Change Materials (PCMs). These composites consist of Paraffin Wax (PW) as the base material, incorporating dispersed conducting Polyaniline (PANI) powder in varying concentrations ranging from 1% wt. to 4% wt. The mass fractions of PANI added to PW include 1%, 2%, 3%, and 4%, and the composite PCMs are meticulously prepared through ultrasonication. Examining the surface morphology of Composite Phase Change Materials (PCMs) involved utilizing a Scanning Electron Microscope (SEM), while the determination of thermal conductivity employed a Heat Flow Meter. Additionally, latent heat and phase change temperatures were assessed through Differential Scanning Calorimetry (DSC). The obtained results indicate an augmentation in the thermal conductivity of the composites when compared to Paraffin Wax (PW). Specifically, thermal conductivity exhibited a 40% increase for 1% wt. of PANI, yet experienced a subsequent decline for the remaining weight percentages. Furthermore, the latent heat and phase change temperatures of the composites were observed to decrease in comparison to PW. These composite PCMs with enhanced thermal conductivity, achieved through the incorporation of Polyaniline in Paraffin Wax, are highly potential for several applications in energy storage systems, thermal regulation devices, and heat management technologies. [ABSTRACT FROM AUTHOR]

Solvent-borne polyurethane (PU) is the main product in PU synthetic leather, which has soft handling, breathability, and moisture permeability properties by wet type. The PU film would produce the irregular foam cell by solvent exchanging water. This traditional process would use a lot of dimethylformamide, and it causes much pollution of the environment. Therefore, the water-borne polyurethane system is essential in the textile industry. This study adopted the patented prepolymer process for solvent-free water-borne polyurethane (SFWPU); the foam was formed by a blowing agent and then, coated on the polyester textile with SFWPU foam by coating machine. This research focuses on the polyol composition equivalent ratio of poly(1,4-butylene adipate) glycol (PBA) and poly(tetramethylene ether) glycol from 30:70, 20:80, 10:90, and 0:100. The crystallinity increased on the foam properties with increasing the PBA composition, affecting the foam and tensile properties. Moreover, this research finds that higher crystallinity polyol of PBA contents increased, modulus of SFWPU is increased, and tensile strength is decreased. The scanning electron microscope finds the foam cell would expand by increasing PBA contents, which affects the textile's air permeability and water vapor transmission. The 10% PBA equivalent of ester–ether type SFWPU foam coated on textile, which has windproof and keeps the moisture permeability. [ABSTRACT FROM AUTHOR]

In this study, multiple emulsions stabilized by hydrophobic-hydrophilic cellulose particles from oil palm empty fruit bunch were studied. The responsiveness of the emulsions to pH and the influenced on the release of encapsulated vitamin B9 was studied using high performance liquid chromatography. The cellulose was characterized using Fourier transform infrared spectroscopy, scanning electron microscope, energy-dispersive X-ray spectroscopy, thermogravimetric analysis, differential thermogravimetric and X-ray diffraction. The result showed that crystallinity of native cellulose and modified cellulose were 66.12% and 61.38%, respectively. The emulsions stabilized by hydrophobic-hydrophilic cellulose particles showed unique responsiveness at pH 2, 4 and 7. The droplet size of the emulsion and the release of active constituent (vitamin B9) depends on the pH. The encapsulation efficiency of w/o/w multiple emulsions at pH 4 and 7 was 78.41% and 65.95%, respectively. The result showed that the release of active constituent from w/o/w multiple emulsions can be controlled based on the responsiveness to pH, to develop fascinating new applications for some specific foods, pharmaceuticals, and drug release. [ABSTRACT FROM AUTHOR]

Nowadays, researches on the use of alkali metal salts as friction‐reducing and anti‐wear oil additives are continuing. In this study, the tribological effects of heavy metal containing MoS2 and alkali metal salt CaF2 additives on pure engine oil (20W50) were investigated using block‐on‐ring tester configured as surface contact geometry. The tests were performed at various contact loads, revolutions, and additive ratios. The crystal structure of the additives and their effects on surface quality and surface roughness analysed by x‐ray crystallography, scanning electron microscope and profilometry. Moreover, Energy dispersive spectrometry was used for element detection on worn surfaces. Results indicated that additives of MoS2 and CaF2 can reduce the friction, increase the capacity of load‐carrying and the wear resistance of surfaces. The additives improved the operation of the base oil in boundary lubrication zone by increasing the tribofilm forming effect. It was observed that the CaF2 additive exhibited more stable friction behaviour, while the MoS2 additive has better protective effects against scratches on the block surface. [ABSTRACT FROM AUTHOR]

Summary: The stability, microstructure and antioxidant capacity of the composite coating solution of chitosan (CS) and oleuropein (OLE, 0.08–0.32%, w/v) were estimated by zeta potential, rheological properties, scanning electron microscope and 2,2‐diphenyl‐1‐picrylhydrazyl radical scavenging assays. Effects of the composite coating on refrigerated chicken breasts were evaluated by microbial, chemical and sensory assays. The results revealed that the coating solutions were stable, intact and exhibited good antioxidant activities. When chicken samples were stored at 4 °C for 12 days, the microbial population treated with CS + OLE decreased to 5.43–7.59 log CFU g−1 compared with the control (8.41 log CFU g−1). The increase in pH values, total volatile base nitrogen and thiobarbituric acid reactive substances contents, and drip loss rate of chicken samples had also been deferred. Overall, the results indicated that it was feasible to apply CS with OLE to extend the shelf life of chicken breasts. [ABSTRACT FROM AUTHOR]

Poly(S-bioallethrin) (PSBA) was grafted onto the polyvinylidene fluoride (PVDF) molecular chain through a gamma-ray irradiation method to prepare the PVDF-g-PSBA membrane. Fourier transform infrared spectroscopy (FTIR) of different membranes confirmed the effective progress of the grafting reaction. The microstructure of the membrane before and after irradiation was analyzed by scanning electron microscope (SEM), illustrating that gamma-ray irradiation did not cause damage to the membrane structure. The original PVDF membrane and the modified PVDF-g-PSBA membrane were immersed in an Escherichia coli culture medium, and the antibacterial effects of membranes were tested, confirming the positive effect of the PVDF-g-PSBA membrane on inhibiting bacterial growth. This research could have market application value in terms of altering membrane materials and enhancing membrane performance. [ABSTRACT FROM AUTHOR]

PANI is a nanostructure conductive polymer that has been widely researched by making nanofibers using electrospinning, by adding PVA as a non-conductive material. In this research, we have successfully synthesized PVA/PANI nanofiber using the electrospinning method and applied it as a humidity sensor. The oxidation polymerization method was conducted to produce polyaniline (PANI) powder. PVA was used as a non-conductive polymer to carry PANI. PANI is blended with 10 % PVA to produce nanofiber PVA/PANI. The results of the synthesis of PVA/PANI nanofibers using the electrospinning method have been characterized by FTIR and EDX to identify the functional groups and elements of PVA/PANI. The FTIR results confirmed that for the PVA nanofiber samples, the type of polyvinyl alcohol bond has been identified according to the reference. The EDX results show the elements C, O and N. The element nitrogen (N) is the characteristic element of polyaniline (C6H5(NH)2)n. The optical Microscope and Scanning Electron Microscope show that the electrospinning method has succeeded in synthesizing PVA/PANI nanofibers with a fiber size of around 0.313 mm. The porosity of PVA/PANI is around 55 %, which is related to the ability of PVA/PANI sensitivity to detect humidity. These results are demonstrated by measurements using a Four-Point Probe (FPP), with the humidity value varying from 64 - 80 %. The results show that variations of PANI powder content improve the sensitivity performance of PVA/PANI nanofibers. This method can optimize PVA/PANI nanofiber as a humidity sensor, increase conductivity flexibility, make it easier and enhance the PANI to use as an active sensor. [ABSTRACT FROM AUTHOR]

The aim of this research was to produce a film based on the mucilage of Paneerak flower modified with licorice root and copper sulfate nanoparticles. The D-optimal statistical scheme was used to study the antioxidant, antimicrobial, X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM) and thermal decomposition (DSC) properties of the films. The results showed that with the increase of licorice root and copper sulfate nanoparticles, the antioxidant activity of the film increased significantly (p<0.05). The results of the antimicrobial activity of the prepared films showed that the addition of licorice and copper sulfate nanoparticles caused the antimicrobial activity of the film against Escherichia coli and Staphylococcus aureus. X-ray diffraction analysis shows that copper sulfate nanoparticles are physically combined with the mucilage polymer of Paneerak flower and it reduces the crystal structure.Fourier transform infrared (FTIR) results confirm the physical presence of copper sulfate nanoparticles in the polymer matrix. FTIR results also showed weak electrostatic interactions between film components and composites. The results of the scanning electron microscope (SEM) show that the surface of the films containing copper sulfate nanoparticles and licorice root are more heterogeneous than the mucilage of Paneerak flower. Shirin-bian and copper sulfate nanoparticles were able to delay the thermal decomposition of the mucilage of Paneerak flower and increase the thermal stability of the mucilage film. Finally, based on the results, the addition of copper sulfate nanoparticles and licorice root to edible films based on the mucilage of paneerak flower improved antimicrobial, antioxidant, DSC and SEM. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the influence of different preparation tapers on the reduction in planktonic bacteria and biofilms of Enterococcus faecalis and Candida albicans in the apical third (4 mm) of the mesial roots of mandibular molars, correlating decontamination with canal shape. Methodology: After microtomography analysis for morphological standardization of the canals, 48 mandibular molar roots, each containing two canals (96 canals), were contaminated with E. faecalis and C. albicans and divided into four groups (n = 11) for canal instrumentation using ProDesign Logic 2 files with different tapers G (.03): # 25.03; G (.04): # 25.04; G (.05): # 25.05; and G (.06): # 25.06 and irrigation with 2.5% sodium hypochlorite. Four roots were examined under a scanning electron microscope (SEM) to qualitatively assess biofilm formation. Eight roots were used as the negative control group (samples were not contaminated). Bacteriological samples were taken exclusively from the apical third of the roots before and after chemical–mechanical preparation and bacterial counts were determined (CFU/mL). The final micro‐CT scan was used to quantify the volume variation and unprepared canal area in the apical third. Statistical analysis was performed using the Kruskal–Wallis, Student–Newman–Keuls and Wilcoxon tests for analysis of microbiological data. anova and the Tukey or Games–Howell test were used for analysis of micro‐CT data and Spearman's test for correlations (α = 5%). Results: All groups showed a significant reduction in bacteria (p <.05), with no statistically significant difference between groups. There was no significant difference in per cent volume increase between groups. The unprepared area (Δ%) was affected by the file used (p =.026) and was significantly lower for G (.06) compared to G (.03). There was no statistically significant correlation among bacterial reduction, volume and unprepared area (p >.05). Conclusion: The different preparation tapers influenced root canal shaping in the apical third but did not improve decontamination in this region. [ABSTRACT FROM AUTHOR]

The development of the industry has increased the demand for energy storage, making the provision of energy storage devices essential. The supercapacitor is one of the potential energy storage devices, and carbon aerogel (CA) is a promising candidate for supercapacitor electrode fabrication. Ni-doped nipa palm shell-derived CA (Ni-NS-CA) was used to fabricate the electrode for supercapacitors to save production costs and utilize biomass wastes. Ni-NS-CA was synthesized via a three-step process: Hydrogel making through cross-linking (SA, Ni2+), freeze-drying, and pyrolysis. The characteristics of Ni-NS-CA are analyzed using a scanning electron microscope, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, Raman spectroscopy, and Nitrogen adsorption–desorption isotherm 77 K. The electrochemical properties of Ni-NS-CA was analyzed via cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy. With stable energy storage results (104.15 F g−1) and the electrochemical system based on Ni-NS-CA extends its application to Hg2+ sensing. Moreover, Ni-NS-CA was a potential material to solve oil spills, which has an oil adsorption capacity of 31.24 g g−1. [ABSTRACT FROM AUTHOR]

Seasonal variation of soil surface temperature, such as freezing and thawing, can induce increases in the water permeability in clay by mobilizing clay pore structure. This kind of weather-induced change in clay behavior may worsen the water-sealing performance during the construction and after closure operation of engineered structures such as soil barriers for tailings or man-made slopes. There is limited knowledge towards the influence of freezing–thawing cycles on clay microstructure and saturated permeability (Ksat). This study investigated the saturated permeability of clay under freezing–thawing cycles and explored the uses of biochar as eco-friendly amendment to manipulate the permeability of compacted clay. Clay specimens were compacted with different initial water contents (30%, 34%, and 38%). The biochar application rates of 0%, 2%, 4%, 8% (by dry weight) were applied to measure their effects on the permeability of clay specimens. Saturated permeability was measured by the falling head tests. Any variation of biochar amended clay microstructure after freezing–thawing cycles was captured by the scanning electron microscope. The Ksat was reduced by about one order of magnitude when the biochar application rate was larger than 4%. This may be attributed to the increase in the filling of the biochar particles in the clay intra-aggregate pores upon the transport of liquid water during the repeated freezing–thawing processes. The biochar may thus be recommended to minimize the Ksat of geo-environmental structures in cold regions when sufficiently large application rate was used to facilitate the pore-filling process. [ABSTRACT FROM AUTHOR]

Chlorpyrifos (CPF) is an organophosphate pesticide that has been used for decades to enhance crop yield but its persistent usage has led to dreadful health issues in humans as well as other species. In the current work, an electrochemical sensor has been fabricated with immobilized molecularly imprinted polymers (MIPs) on a glassy carbon electrode to detect CPF. MIPs were bulk polymerized with a functional monomer itaconic acid. MIPs were characterized by Fourier transform infrared spectroscopy, scanning electron microscope, cyclic voltammetry and electrochemical impedance spectroscopy. The execution of the developed electrochemical sensor was scrutinized with differential pulse voltammetry (DPV). Various parameters like the pH of the electrolyte, the concentration and volume of MIPs (after elution), and the adsorption time were optimized for the analysis of the analyte (CPF) with the fabricated sensor. Under optimal conditions, the peak current of different CPF concentrations was examined by DPV method. The peak current was in linear proportionality with CPF (2.8 × 10−14 to 2.8 × 10−5 mol l−1) with a low detection limit of 1.912 × 10−14 mol l−1. The developed electrochemical sensor detected CPF in real samples with excellent results and a recovery percentage ranging from 100 to 106% (relative standard deviation, RSD < 5%). Also, the sensor exhibited good reproducibility, stability and selectivity. Therefore, the developed electrochemical sensor holds great potential for the monitoring of CPF in fruits and vegetables. [ABSTRACT FROM AUTHOR]

Machining of silica glass is a challenging task due to its physical properties like brittleness, electrically insulated, etc. Although with the use of electrochemical discharge, it is possible to make holes and channels in silica glass, but the generation of spark discharge and removal of materials is a complex phenomenon in the electrochemical discharge process. Several research works were carried out previously to control the spark discharge as well as machining accuracy using rotational tool, the addition of ultrasonic vibration, including a magnetic field, and the use of different electrolytes, etc. A novel tool feeding technique i.e. using a horizontal tool and vertically upward tool feeding technique was used during milling on glass. The effects of voltage, the tool feed rate (TFR) and the concentration of electrolyte on the material removal rate and machining quality were studied in this work. The machined channel was examined under an optical measuring microscope as well as scanning electron microscope. The machining surface was also observed using a coherence correlation interferometry image to analyze in-depth surface topography of machined channels. Material removal rate and Ra value of the bottom layer were measured. The material removal rate of 6.097 µg/min was noticed at 25 wt% of electrolyte concentration, 40 µm/s of TFR and 45 V of applied voltage. The bottom layer's surface roughness (Ra) was found as low as 0.222 µm (Ra) at parametric conditions of 40 V, 40 µm/s TFR, and 15 wt% electrolyte concentration by employing the developed novel tool feeding technique. [ABSTRACT FROM AUTHOR]

A composite coating of Ni–W–Ti 2 AlC was fabricated through direct current electrodeposition. The characterization of the composite coatings included analysis using X-ray diffractometry, scanning electron microscope, energy spectrum analysis, Vickers microhardness testing, electrochemical testing, and tribological testing. The findings indicate that the inclusion of Ti 2 AlC alters both the grain size and microstructure of the coatings. The presence of Ti 2 AlC particles facilitates the nucleation process during Ni–W–Ti 2 AlC deposition. The Ti 2 AlC content influences the coating's performance in the bath. Specifically, the microhardness of the Ni–W-(5 g/L) Ti 2 AlC coating exhibits the highest value, experiencing a 41.89 % increase compared to that of the Ni–W coating. Ti 2 AlC contributes to the rectification of defects in the Ni–W–Ti 2 AlC coating. This composite coating exhibits the lowest corrosion current and superior corrosion resistance, particularly with a Ti 2 AlC concentration of 5 g/L. The wear mechanism of the coating encompasses abrasive wear, adhesive wear, and oxidation wear. Notably, the Ni–W–Ti 2 AlC composite coating demonstrates enhanced friction resistance compared to the Ni–W composite coating. Incorporating Ti 2 AlC introduces a novel approach and avenue for fabricating high-performance tungsten-based functional coatings. [ABSTRACT FROM AUTHOR]

The applications of Si 3 N 4 ceramics are hindered by their brittleness and susceptibility to fracture, despite their high strength and wear resistance. To address this challenge, layered ceramics were prepared using lamination and plasma sintering techniques, inspired by the structure of shell pearl layers. The bio-inspired layered ceramics were alternately arranged with Si 3 N 4 as the matrix layer (hard) and BN as the interfacial layer (soft). During the study, ceramic specimens with different microstructures were obtained by modulating the layer thickness ratio (ratio of Si 3 N 4 to BN) and sintering temperature. The microstructure of the specimens was characterized using SEM (Scanning Electron Microscope) and EDS (Energy Dispersive Spectrometer). The mechanical of various specimens were assessed by measuring the flexural strength and fracture toughness. The results of the investigation revealed that the mechanical characteristics of the samples reached their optimum state (with a toughness of 13.51 ± 1.56 MPa m1/2 and a strength of 429 ± 4.28 MPa) when the ratio of Si 3 N 4 to BN was 5:1, and the sintering temperature was maintained at 2000 °C. [ABSTRACT FROM AUTHOR]

The objective of this paper is to assess the impact of mineral grain size and grain size distribution of aggregates on the deterioration of pavement surface microtexture. For the study, aggregates were collected from nine different sources to cover a wide variation in mineralogical type. The grain size parameters were obtained by detecting mineral grain boundaries using scanning electron microscope electron back scattered diffraction (SEM EBSD) analysis on thin sections prepared from the aggregates. Scanning electron microscope (SEM) analysis was also carried out on thin sections of all aggregate types to determine their mineralogical composition. Microtexture deterioration was measured by collecting the British pendulum number (BPN) of the aggregate after every hour of polishing for six hours using an accelerated polishing machine. From the mineral composition analysis, it was observed that the aggregates in the study belonged to three rock types: granite, amphibolite, and basalt (three sources of each type). The BPN values of the polished stones indicated that aggregates with finer grains offer more resistance to polishing. Statistical analysis of the test results also suggests that a wide variation in grain sizes in aggregates positively contributes to resistance against polishing. The study confirmed that, for a given rock type, coarse aggregates with finer grains and greater variation in grain size can better withstand microtexture deterioration caused by mechanical polishing from vehicular loads when used in the surface course of pavements. [ABSTRACT FROM AUTHOR]

In this study, enzyme-induced carbonate precipitation (EICP) combined with xanthan gum curing technology was used to improve the engineering properties of standard sand, and the curing effect of EICP combined with different xanthan gum contents was studied by macroscopic tests such as unconfined compressive strength, direct shear, permeability, calcium carbonate content, and microscopic tests such as scanning electron microscope and nuclear magnetic resonance. The results show that the unconfined compressive strength, shear strength, cohesion and internal friction angle of EICP combined with xanthan gum solidified sand increases with the increase of xanthan gum content and reaches the maximum value at the content of 2%, in which the increase of unconfined compressive strength, shear strength, and cohesion is significant; further, the increase of internal friction angle is small. The permeability coefficient of EICP combined with xanthan gum solidified sand decreases with the increase of xanthan gum content, and the permeability coefficient of 2% xanthan gum is only 65.4% that of pure EICP treatment. The incorporation of xanthan gum promotes the deposition of calcium carbonate, increases the viscosity of the reaction solution, and produces colloidal encapsulation and bonding effect on the sand particles. In addition, the incorporation of xanthan gum effectively reduces the porosity of solidified sand and greatly reduces the proportion of large pores and medium pores by changing the pore size, which greatly improves the pore structure. [ABSTRACT FROM AUTHOR]

In this paper, fiber Bragg grating (FBG) sensors were applied to investigate the frost resistance of C60 concrete. First, the growth of both the static and dynamic elastic modulus of C60 concrete with curing age was investigated using an FBG, the standard method, and the resonance method, respectively. Second, to simulate the freezing and thawing conditions in cold regions, the concrete specimens were subjected to air freezing and water thawing using the slow freezing method. The authors explored the effect of freeze–thaw cycles on the mechanical properties of concrete and established a mathematical model relating its mechanical properties to freeze–thaw cycles based on an FBG sensor. Meanwhile, its compressive strength, dynamic elastic modulus, and mass loss rate were tested. Finally, the interface morphology and hydration products of concrete were observed using a scanning electron microscope (SEM) after freeze–thaw cycles. The results indicate that both the static and dynamic elastic modulus of C60 concrete increase with curing age. Its elastic modulus measured by FBG is approximately the same as that measured by the standard method, confirming the viability of using an FBG sensor to measure its elastic modulus. Furthermore, the authors highlighted the dependence of its compressive strength on the freeze–thaw cycles. The relationship of the static elastic modulus to freeze–thaw cycles is similar to that of the dynamic elastic modulus and mass loss rate. A static elastic modulus achieved from an FBG is proposed here to characterize the frost resistance of C60 concrete. [ABSTRACT FROM AUTHOR]

Magnesium oxychloride cement (MOC) is an environment-friendly cement often used for stabilizing soft soils because of its exceptional mechanical properties. In this study, the influence of curing temperature on the strength development of MOC-solidified clay is explored, considering different MgO/MgCl2 molar ratios. Different tests were carried out to study the corresponding effects. The results show that the effect of curing temperature on the strength of MOC-solidified clay differs greatly from that of cement-solidified soil. Increasing the curing temperature leads to strength reduction, whereas decreasing the curing temperature increases the corresponding strength. Scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses indicate that the variation in type and amount of hydration products of the solidified soil account for the strength development difference between MOC-solidified and cement-solidified soils. A model based on the experimental results is proposed to characterize the relationship between strength development and curing time. The strength influence factor (ηT) and the strength expedite factor (K) were introduced to demonstrate the relationship between strength development at a specific curing temperature as well as at room temperature. [ABSTRACT FROM AUTHOR]

In this study, enzyme-induced carbonate precipitation (EICP) combined with chitosan curing technology was used to improve the mechanical properties of standard sand, and the curing effect of EICP combined with different chitosan contents was studied by macroscopic tests, such as the unconfined compressive strength test, direct shear test, and calcium carbonate content test, and microscopic tests, such as scanning electron microscope (SEM) and nuclear magnetic resonance (NMR). The results show that compared with the pure EICP treatment, the unconfined compressive strength, shear strength, and calcium carbonate content of the sand treated by EICP combined with chitosan were significantly improved, and increased first and then decreased with the increase of chitosan content, reaching the maximum value when the content is 1.5%. The calcium carbonate content is positively correlated with the strength, indicating that calcium carbonate crystals can effectively play a role in filling and cementation. After the incorporation of chitosan, the shape of calcium carbonate crystals is still mainly spherical, but the number and volume become larger. At the same time, the incorporation of chitosan can greatly reduce the proportion of large pores and medium pores, significantly increasing the proportion of small pores, which greatly improves the pore structure. [ABSTRACT FROM AUTHOR]

In this research, the preparation of licorice extract and the biosynthesis of manganese oxide in the treatment of stomach cancer were investigated by examining the cytotoxicity of the stomach cancer line. The structural properties of manganese oxide were also studied through X-ray examination, scanning electron microscope (SEM), and infrared spectroscopy, where it was found that manganese oxide is polycrystalline, and the average grain size is 62.571 nm, but by SEM, the grain size is 93.49-47.74 nm. [ABSTRACT FROM AUTHOR]

Cracks generated in sheet coating of water-based slurries are an increasingly important concern in the development of diverse material science, such as fine ceramics, Pt catalysts, and Li transition metal oxides, from an environmental safety perspective. However, a comprehensive understanding of crack formation remains elusive due to the intricately entangled interplay among various characteristics of slurries. Here, we systematically ascertain the causes at work in crack initiation by analyzing the physical parameters of a series of aqueous alumina slurries using machine learning. The analysis reveals a strong correlation between rheological hysteresis and sheet cracking. As a verification of the correlation, the crack suppression by controlling the rheological hysteresis is experimentally confirmed. Furthermore, we visualize the microstructure in the slurry that induces cracks with a liquid-phase scanning electron microscope, clarifying the rheological dynamics. These results disentangle that rheological hysteresis is a good indicator directly reflecting microstructural durability against drying stress. [Display omitted] [ABSTRACT FROM AUTHOR]

BACKGROUND: Polyvinylidene fluoride (PVDF) with piezoelectric properties, good biocompatibility and nontoxicity make it a suitable candidate for periosteal repair. OBJECTIVE: To evaluate the cytotoxicity of PVDF bionic periosteum by electrospinning with zinc and magnesium ions in vitro. METHODS: Pure PVDF, zinc-doped PVDF, magnesium-doped PVDF and Zinc-magnesium ion PVDF piezoelectric bionic periosteum were prepared by electrospinning technology, respectively. They were named PVDF, PVDF-Zn, PVDF-Mg and PVDF-Zn-Mg, in which the mass fraction of zinc and magnesium ions were all 1%. Osteoblasts and vascular endothelial cells were co-cultured with four groups of bionic periosteum. Cell compatibility of bionic periosteum was determined by alkaline phosphatase staining, CD31 immunofluorescence staining, and scanning electron microscopy. RESULTS AND CONCLUSION: (1) Osteoblasts: Alkaline phosphatase staining after 7 days of culture showed that the PVDF-Zn group secreted more alkaline phosphatase than the other three groups. Under a scanning electron microscopy, after 1 day of culture, the cells had a certain spread on the surface of PVDF-Mg and PVDF-Zn-Mg bionic periosteum, and the pseudopod extended to all sides. On day 3, the cell edge of each group extended pseudopods to the material. By days 5 and 7, the cells were fully spread, well grown and firmly covered the surface of the fibers, and the cellular pseudopods extended around and into the interstitial space of the fibers. CCK-8 assay showed that the cell proliferation on the bionic periosteum of each group showed an increasing trend over time and the relative proliferation rate of cells at 1, 3, 5, and 7 days was ≥75%, and the cytotoxicity was ≤ grade 1. (2) Vascular endothelial cells: CD31 immunofluorescence staining for 3 days showed that the cells adhered and spread well on the bionic periosteum of each group and connected with each other, and the number of cells in the PVDF-Zn-Mg group was more than that in the other three groups. Under scanning electron microscope, the cells began to adhere to the surface of each group of fibers after 1 and 3 days of culture. On day 5, the cells were well spread on the surface of the fibers and extended obvious pseudopods. On day 7, the cells on the PVDF-Mg and PVDF-Zn-Mg bionic periosteum grew in multiple layers and extended the pseudopod into the fibrous void. CCK-8 assay showed that the cell proliferation on the bionic periosteum of each group showed a downward trend over time, and the relative proliferation rate of cells at 1, 3, 5 and 7 days was ≥125%, and the cytotoxicity was grade 0. (3) The results showed that Zn-Mg electrospun PVDF piezoelectric bionic periosteum had good cytocompatibility. [ABSTRACT FROM AUTHOR]