Scanning Transmission Research Articles

Atomic Fabrication of 2D Materials Using Electron Beams Inside an Electron Microscope

Two-dimensional (2D) materials have garnered increasing attention due to their unusual properties and significant potential applications in electronic devices. However, the performance of these devices is closely related to the atomic structure of the material, which can be influenced through manipulation and fabrication at the atomic scale. Transmission electron microscopes (TEMs) and scanning TEMs (STEMs) provide an attractive platform for investigating atomic fabrication due to their ability to trigger and monitor structural evolution at the atomic scale using electron beams. Furthermore, the accuracy and consistency of atomic fabrication can be enhanced with an automated approach. In this paper, we briefly introduce the effect of electron beam irradiation and then discuss the atomic structure evolution that it can induced. Subsequently, the use of electron beams for achieving desired structures and patterns in a controllable manner is reviewed. Finally, the challenges and opportunities of atomic fabrication on 2D materials inside an electron microscope are discussed.

Stimuli-Responsive Vesicles and Hydrogels Formed by a Single-Tailed Dynamic Covalent Surfactant in Aqueous Solutions

Controlling the hierarchical self-assembly of surfactants in aqueous solutions has drawn much attention due to their broad range of applications, from targeted drug release, preparation of smart material, to biocatalysis. However, the synthetic procedures for surfactants with stimuli-responsive hydrophobic chains are complicated, which restricts the development of surfactants. Herein, a novel single-tailed responsive surfactant, 1-methyl-3-(2-(4-((tetradecylimino) methyl) phenoxy) ethyl)-3-imidazolium bromides (C14PMimBr), was facilely fabricated in situ by simply mixing an aldehyde-functionalized imidazolium cation (3-(2-(4-formylphenoxy) ethyl)-1-methyl imidazolium bromide, BAMimBr) and aliphatic amine (tetradecylamine, TDA) through dynamic imine bonding. With increasing concentration, micelles, vesicles, and hydrogels were spontaneously formed by the hierarchical self-assembly of C14PMimBr in aqueous solutions without any additives. The morphologies of vesicles and hydrogels were characterized by cryogenic transmission electron microscopy and scanning electron microscopy. The mechanical properties and microstructure information of hydrogels were demonstrated by rheological measurement, X-ray diffraction, and density functional theory calculation. In addition, the vesicles could be disassembled and reassembled with the breakage and reformation of imine bonds by adding acid/bubbling CO2 and adding alkali. This work provides a simple method for constructing stimuli-responsive surfactant systems and shows great potential application in targeted drug release, drug delivery, and intelligent materials.

Infiltration of glass nanofiber-reinforced polylactic acid into delignified hardwood toward photoluminescent and mechanically reliable smart windows

Ultraviolet-protective, mechanically reliable, and photoresponsive wood that can switch color under ultraviolet light was developed. A combination of alkaline earth-doped strontium aluminate (ASA) as a photoluminescent pigment and glass nanofiber-supported polylactic acid as a hosting agent was infused into a delignified wood, producing transparent wood with photochromic activity. The ASA phosphor has proven high thermal stability and photostability. A typical process for producing colorless photoluminescent wood includes the well-dispersion of ASA in glass nanofiber-supported polylactic acid without agglomeration. As proven by the coloration measurements, the current photoluminescent wood becomes green under ultraviolet light and remains transparent under daylight. Transmission electron microscopy (TEM) and scanning electron microscope (SEM) were employed to determine the morphology of the phosphor particles and glass fibers, demonstrating sizes of 12–21 nm and 50–125 nm, respectively. The luminescent wooden samples were studied by numerous microscopic and spectroscopic techniques, including SEM, X-ray fluorescence (XRF), and energy-dispersive X-ray (EDX). Upon excitation at 365 nm, the luminescence wood demonstrated an emission peak at 518 nm. When increasing the ASA concentration, the photoluminescent hardwoods displayed improved ultraviolet protection and better water resistance. The responsiveness of the luminescent wood to UV irradiation was fast and reversible.

A novel molecularly imprinted electrochemical sensor based on MnO-Fe3O4@C was designed with DFT theoretical study for the detection of thiamphenicol in food

In this study, a new molecularly imprinted electrochemical sensor is presented for thiamphenicol (TAP) based on MnO-Fe3O4@C and a molecularly imprinted polymer (MIP). In the synthesis process of MIP, the density functional theory (DFT) was applied to simulated the interaction between different functional monomers and template molecules, and screen the optimal functional monomers and the ratio of optimal template molecules to functional monomers, which guided the electrochemical in-situ polymerization of MIP. The composite materials were evaluated by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM) and scanning electron microscopy (SEM), and the electrochemical performance of molecular imprinted electrode was evaluated by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). Under the optimal conditions, there is a strong linear correlation between the current response and TAP concentration in the 0.01–1 μM (R2=0.9988) and 1–40 μM (R2=0.9954) range. The lowest detection limit (S/N = 3) was 0.007 μM. Besides, the sensor has good reproducibility, stability and anti-interference ability, and has successfully detected analytes in milk and egg samples, which provides application prospects for constructing selective detection of TAP in food samples.

Valence state and redox property of Fe‐CNTs added CeO2/TiO2 catalyst

AbstractThe investigation focused on examining the impact of incorporating Fe‐carbon nanotubes (CNTs) on the valence state and oxygen vacancies, and the physicochemical parameters of the catalytic system. For the CeO2/TiO2 catalyst with Fe‐CNTs, no distinct X‐ray diffraction (XRD) peaks corresponding to Fe‐CNTs were observed. This indicated their uniform dispersion, supported by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) imaging. X‐ray photoelectron spectroscopy (XPS) analysis was conducted to observe the changes in the valence state due to the addition of Fe‐CNTs. The concentration of Ce3+ on catalyst surface increased from 19.90% to 29.48% with an increased concentration of the chemisorbed oxygen species (Oα). This suggests that the addition of Fe‐CNTs into CeO2/TiO2 catalyst reduced Ce4+ on the catalyst surface, resulting in the formation of oxygen vacancies. Oxygen temperature‐programmed desorption (O2‐TPD) and hydrogen temperature‐programmed reduction (H2‐TPR) analyses showed both the adsorbed oxygen species and H2 consumption increased with adding Fe‐CNTs. Furthermore, the onset temperatures for O2 desorption and H2 consumption became lower, confirming the enhancement of catalytic redox properties.

Revealing the Failure Mechanisms of Lithium Metal Solid‐State Batteries with Solid Inorganic Electrolytes by In situ Electron Microscopy

Lithium metal solid‐state batteries (LMSSBs) are considered to be one of the ultimate choices for future energy storage systems because of their high theoretical energy density and enhanced safety. However, the development of LMSSBs has been seriously hindered by some practical issues, such as Li dendrite penetration in the solid‐state electrolytes (SSEs) and uncontrolled interphase growth at the Li/SSE interface, which can cause severe battery degradation, failure, and even safety hazards. To construct safe high‐performance LMSSBs, it is crucial to gain an in‐depth understanding of the failure mechanisms induced by these challenges, especially through direct visualization of the failure processes. In this review, the recent progress on the mechanistic study of LMSSBs by in situ electron microscopy is summarized. In situ transmission electron microscopy (TEM) and scanning electron microscopy (SEM) offer an opportunity to probe the battery failure mechanism by observing the associated physical and chemical processes at nano/atomic resolution. The failure causes of Li dendrites growth and interphase formation are classified and discussed, followed by the corresponding solutions to address these issues. Additionally, the emerging perspectives on future research directions in this field are also summarized.

Fabrication of Antibacterial Graphene Oxide/Copper Nanocomposites.

Antibiotics are currently the most used antibacterial treatment for killing bacteria. However, bacteria develop resistance when continually overexposed to antibiotics. Developingantimicrobial agents that can replace existing antibiotics is essential because antibiotic-resistant bacteria have resistance mechanisms for all current antibiotics and can promote nosocomial infections. To address this challenge, in this study, we propose graphene oxide/copper (GO/Cu) nanocomposites as antibacterial materials that can replace the existing antibiotics. GO/Cu nanocomposites are characterized by transmission electron microscopy and scanning electron microscopy. They show that copper (Cu) nanoparticles are well-grown on the graphene oxide sheets. Additionally, a microdilution broth method is used to confirm the efficacy of the antimicrobial substance against methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (P. aeruginosa), which are frequently implicated in nosocomial infections. Specifically, 99.8% of MRSA and 84.7% of P. aeruginosa are eliminated by 500 µg/mL of GO/Cu nanocomposites. Metal nanocomposites can eradicate antibiotic-resistant bacteria by releasing ions, forming reactive oxygen species, and physically damaging the bacteria. This study demonstrates the potential of antibacterial GO/Cu nanocomposites in eradicating antibiotic-resistant bacteria.

Optimization of high-temperature mechanical properties of aluminum alloys through exclusive precipitation of T-phase

An aluminum alloy with an actual composition of Al - 5.4 wt%Cu- 1 wt%Mn was cast and subjected to solution heat treatment for 1 h, 2 h, 4 h, 8 h, and 16 h to make the T-phase the sole strengthening phase. The microstructural evolution of the samples, especially the T-phase microstructure, was studied using transmission electron microscope (TEM) and scanning electron microscope (SEM) with electron backscatter diffraction (EBSD) attachment. The ImageJ software was utilized to statistically analyze T-phase content. Tensile tests were conducted to obtain mechanical property data, and high-temperature tensile tests were performed at 200 °C, 300 °C, and 400 °C to assess the high-temperature performance. Subsequently, the strengthening effect of the T-phase on the room-temperature and high-temperature mechanical properties of the aluminum alloy was quantitatively evaluated. The sample subjected to an 8 h solution treatment exhibited optimal strength and toughness. The yield strength was 147 MPa, and the tensile strength was 300 MPa. The yield strength contributed by the T-phase was 73 MPa. The tensile strength of the sample at 400 °C remained at 91 MPa. The T-phase contributes significantly to the mechanical properties of the aluminum alloy both at room temperature and at high temperatures.

Electrospun chitosan//ethylcellulose-vitamin E//ethylcellulose-curcumin tri-chamber eccentric Janus nanofibers for a joint antibacterial and antioxidant performance.

Multifunctional materials with both antibacterial and antioxidant properties are highly desired in many scientific applications. The combination of polysaccharide and multi-chamber nanostructures offers a novel perspective for developing antibacterial and antioxidant nanomaterials. In this study, a new kind of tri-chamber eccentric Janus nanostructures (TEJNs) was fabricated through a single-step and straight forward tri-fluid side-by-side electrospinning. The all-in-one TEJNs contained an outer chitosan (CS) chamber, a middle and an inner ethylcellulose (EC)-based chamber loaded with curcumin (Cur) and vitamin E (VE), respectively. The side-by-side multiple-fluid electrospinning processes were implemented robustly and continuously based on a homemade spinneret. Transmission electron microscope and scanning electron microscope evaluations demonstrated the tri-chamber inner structures of TEJNs and the linear morphologies, respectively. The Fourier transform infrared and X-ray diffraction results verified that the components were compatible and coexisted in an amorphous state. In vitro dissolution tests indicated that the TEJNs could provide a sustained release of 90% of the loaded Cur and VE for 34.30h and 24.86h, respectively. Antibacterial and antioxidant experiments demonstrated that the TEJNs were able to provide enhanced antibacterial and antioxidant effects compared to the traditional electrospun homogeneous nanofibers. In the future, the Janus nanofibers can be further developed for several human health applications, such as wound dressings, active food packaging membranes, dental implants and cosmetic films.

Use of the Pickering Emulsion Method for the Preparation of Nano‐Aluminum Powder/Fluororubber Composite Microspheres

AbstractThe combination of fluoropolymer and nano‐thermite has been a research focus in the field of materials in the field of energy and storage in recent years, but it faces the problem of uneven mixing of fluoropolymer and nano‐aluminum powder (nAl). Therefore, it is of great significance to obtain a fluorine/aluminum uniform composite by a solid/solid phase mixing method. In this paper, Pickering emulsions effectively blend difficult‐to‐mix powders of nAl and solid bulk fluoroelastomers on the micro‐ and nanoscale. The emulsion was prepared by Pickering emulsion with an ethyl acetate solution of fluororubber as the oil phase and perfluorocarboxylic acid‐modified nano‐aluminum powder as a surfactant. The effects of oil/water ratio, fluororubber/aluminum ratio, and standing time on the stability of the emulsion were studied. The nano‐aluminum powder/fluororubber composite microspheres were prepared and their morphology, thermal decomposition, and combustion properties were characterized. The results showed that the emulsion prepared with the oil/water ratio of 1:8 and m(fluororubber):m(modified nano‐aluminum powder) of 5:1 had good stability and dispersion. The transmission electron microscopy (TEM) and scanning electron microscopy (SEM) results showed that the complex was observed to be regular spherical and the size was about 10 µm, and the composite microspheres prepared by the Pickering emulsion had good. The TG‐DSC results showed that the decomposition of the composite microspheres started at about 450 °C and finished at 519 °C. The composite microspheres prepared in this paper are stable and rapid in exotherm, with a combustion rate of 33 cm s−1 and excellent combustion performance. The Pickering emulsion introduces a new idea for the preparation of thermite by mixing the solid reactants at the micro‐nano level without introducing substances that reduce the energy of the system.

Microstructural Characterization of Friction Stir Welds of Aluminum 6082 Produced with Bobbin Tool.

This study utilized a bobbin tool to friction stir weld aluminum 6082 workpieces under two sets of process parameters: a tool rotation speed of 280 rev/min with a weld velocity of 280 mm/min (280/280) and a tool rotation speed of 450 rev/min with a weld velocity of 450 mm/min (450/450). The weld microstructures were characterized through optical microscopy utilizing polarized light and through transmission electron microscopy (TEM) and scanning electron microscopy (SEM) coupled with chemical analysis by energy dispersive spectroscopy and electron back scatter diffraction. The microstructural studies were supplemented by hardness measurements (Vickers) performed on the same sections as the metallographic examinations. The produced weldments were free from cracks and any discontinuities. Fine, equiaxed grains that were several microns in size characterized the stir zones (SZs), and the advancing (AS) and retreating (RS) sides revealed distinct microstructural features. On the AS, the transition from the thermo-mechanically affected zone to the SZ was well defined and sharp, but on the RS, the transition appeared as a continuous, gradual change in microstructure. The lower weld energy (280/280) produced lower hardness in the stir zone than the higher energy weld (450/450), ~95 HV1 versus ~115 HV1; however, the 280/280 welds showed higher tensile strengths than the 450/450 welds, ~238 MPa as opposed to ~172 MPa. These behaviors in mechanical performance correlated with the temperature histories produced by each set of weld parameters in relation to the precipitation behavior of the alloy. The fracture characteristics of the weldments were notably different with the 450/450 sample fracturing in a quasi-brittle manner with slight plastic deformation and the 280/280 sample fracturing ductilely. A numerical simulation supported the investigation by elucidating the temperature and material flow behavior during the joining process.

Biosynthesis and biological activities of magnesium hydroxide nanoparticles using Tinospora cordifolia leaf extract.

The synthesis of magnesium hydroxide nanoparticles (Mg(OH)2 NPs) using plant extracts are known to be a practical, economical, and an environmentally friendly approach. In this work, Mg(OH)2 NPs were synthesized using aqueous leaf extract of Tinospora cordifolia, a medicinal plant commonly found in India. The synthesized Mg(OH)2 NPs were characterized using various spectroscopic techniques. The ultraviolet-visible (UV-Vis) absorption peak of the Mg(OH)2 NPs was detected at 289nm, Fourier transform infrared (FTIR) analysis confirmed the presence of various functional groups, and X-ray diffraction (XRD) patterns revealed the well-crystallized structure of the Mg(OH)2 NPs. High-resolution transmission electron microscopy (HR-TEM) and scanning electron microscopy (SEM) analyses depicted spherical morphology and an average particle size (PS) of 27.71nm. The energy-dispersive X-ray (EDX) analysis confirmed the presence of C, O, and Mg elements, and the X-ray photoelectron spectroscopy (XPS) survey spectrum confirmed the elements for the Su 1s peak at 280.2eV. The dynamic light scattering (DLS) analysis displayed an average PS of 54.3nm, and the Zeta potential (ZP) was of 9.89mV. The fabricated Mg(OH)2 NPs displayed notable antibacterial activity against S. epidermidis, E. coli, and S. aureus. In addition, these NPs exhibited strong antioxidant properties (> 75%) based on DPPH, ABTS, and hydrogen peroxide (H2O2) assays. Further, the same NPs exerted a potent anti-inflammatory activity (> 65%) based on COX-1 and COX-2 evaluations. The anti-Alzheimer' disease (AD) potential of Mg(OH)2 NPs was assessed through effective inhibition (> 70%) of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities. Molecular docking (MD) studies confirmed that caryophyllene has higher binding affinity with AChE (-5.3kcal/mol) and BuChE (-6.4kcal/mol) enzymes. This study emphasizes the green synthesis of Mg(OH)2 NPs using T. cordifolia as a plant source and highlights their potential for biomedical applications.

Nitrogen and Oxygen Dual‐Doped Carbon as High‐Rate Long‐Cycle‐Life Anode Materials for Lithium‐Ion Batteries

Defect‐type carbon, doped with nitrogen and oxygen, is synthesized using the high‐temperature solid‐phase method. X‐ray photoelectron spectroscopy analysis reveals the presence of nitrogen, including pyridine nitrogen, pyrrole nitrogen, and graphitized nitrogen, incorporated into the carbon structure. Additionally, oxygen is introduced into carbon, with both CO and CO functionalities are observed. Transmission electron microscopy and scanning electron microscopy indicate that all samples exhibit a morphology of carbon microblocks with localized turbocharged lattice regions. Electrochemical tests demonstrate that the nitrogen‐ and oxygen‐doped carbon microblocks exhibit excellent cycling performance and high rate capacity. Specifically, at current densities of 1 and 2 A g−1, the rate capacity remains at 385.6 and 214.4 mA h g−1, respectively. Furthermore, the discharge capacity at 5 A g−1 remains at 58.3 mA h g−1 on the 3500th cycle. The defects introduced by nitrogen and oxygen doping not only enhance reactivity and electronic conductivity but also improve lithium‐ion diffusion dynamics.

Per aqueous liquid chromatography of Radix hedysari polysaccharides and Au nanoparticles co-functionalized stationary phase and its application in the determination of iridoids and phenylethanols

BackgroundHydrophilic Interaction Liquid Chromatography (HILIC) is an outstanding strategy for the challenging analysis of hydrophilic and polar components. Nevertheless, analysis under HILIC mode typically consumes 70%–95 % acetonitrile with the disadvantage of high analytical costs, being environmentally unfriendly and causing biohazards, which is not in line with the concept of green chromatography. Research has shown that Per Aqueous Liquid Chromatography (PALC) simultaneously emphasizes efficient analytical performance for hydrophilic analytes and green analytical concepts. The development of new PALC stationary phases with superior performance is necessary. ResultsIn this paper, silanized silica was sequentially subjected to esterification reaction, polymerization reaction and covalent bonding through five steps to obtain SiO2-RHP-AuNPs material, which was prepared as a novel stationary phase for PALC. Comprehensive characterization of the materials by means of Fourier transform infrared spectroscopy, Transmission scanning electron microscope, Elemental analysis and Thermogravimetric analysis showed the successful bonding of the functionalized groups on the original silica. The polymeric stationary phase based on Radix hedysari polysaccharide and Au nanoparticles had higher density of hydroxyl and ester functionalized groups. The Au nanoparticles upgraded their mesoporous structure and thermal stability, providing exceptional chromatographic performance and selectivity for chromatographic analysis. The influence of mobile phase water content, salt concentration, pH and column temperature on the retention behavior was evaluated. The novel Column was found to exhibit a dual mechanism of hydrophobic interactions/ion exchange interactions in a mobile phase with high water content. Significance and noveltyThe separation efficiency and selectivity of SiO2-RHP-AuNPs columns for synthetic pigments and organic acids in PALC mode were superior to those of commercial HILIC and C18 columns. In addition, a method for the determination of seven active ingredients in Fructus Ligustri Lucidi by SiO2-RHP-AuNPs column in PALC mode was developed. The method had good stability, reproducibility and accuracy, which was capable of realizing the quality evaluation of Chinese Materia Medicas.

Advancements in on-site heavy metal detection: Characterizing and sensitive Hg2+ sensing of silver spheroid nanoparticles obtained by laser ablation synthesis in solution

Heavy metal detection in water bodies is crucial to prevent potential harm to the environment, animals and humans. While powerful techniques such as atomic absorption spectrometry exist, they often require extensive sample preparation and are typically confined to laboratory settings. As a result, alternative detection methods such as optical sensors, are under development to provide a simpler, faster, and on-site detection solution. In the present work spheroidal silver nanoparticles (AgNPs) with a mean size of 14.7 ± 0.6 nm were synthesized by laser ablation in a sodium citrate solution. These nanoparticles exhibit a localized surface plasmon resonance (LSPR), which is profoundly dependent on the size, morphology and composition of the nanoparticles and the refractive index of the surrounding media. The detection capabilities of these nanoparticles were assessed by exposing them to various metal ions, revealing a distinctive sensitivity to Hg2+ ions. Notably, this particular ion had a significant impact on the extinction curve of the AgNPs. The impact of synthesis parameters, including sodium citrate and NaCl concentration, as well as pH, on the efficacy of Hg2+ detection was systematically studied. Characterization techniques such as Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), High-Resolution TEM (HRTEM), and Scanning Transmission Electron Microscopy (STEM) were employed to determine the size, morphology, distribution, crystalline structure, and elemental composition of the AgNPs. The results indicated that AgNPs synthesized through laser ablation in a sodium citrate solution exhibited sensitive detection capabilities for Hg2+ ions, reaching an LOD and LOQ of 0.9355 μM and 2.8350 μM respectively.

Isolation and Identification of Flavonoid Compounds from Euphorbia Milii Plant Cultivated in Iraq and Evaluation of its Genetic Effects on Two Types of Cancer Cell Line

يعتبر "تاج الأشواك" أو نبات شوكة المسيح، وهو من نباتات الزينة الطبية ، ينتمي إلى جنس يوفوربيا. E. milii يحتوي كميات وفيرة من المركبات الفينولية ، التربينات، الستيرويدات والقلويدات. كانت الأهداف الرئيسية لهذه الدراسة هي فحص مستخلصات الفلافونويد والنانو فلافونويد ضد نوعين من خطوط الخلايا السرطانية. تم تصنيع مركبات الفلافونويد النانوية عن طريق تفاعل مركب الكيتوسان والماليك اسد. تم تحليل مركبات الفلافونويد النانوية بواسطة مقياس الطيف الضوئي UV-sp -8001 بطول موجي 200-1000 نانومتر ، تم استخدام المجهر الإلكتروني (TEM) والمجهري الإلكتروني الماسح(SEM) لتحديد الخصائص المورفولوجية لمركبات الفلافونويد النانوية. يعتبر الفلافونويد والنانوفلافونويدعقار قوي ومتطور ضد خلايا سرطان الثدي (MCF-7) وخلايا سرطان البروستات(PC3) . تم فحص الفعالية المضادة للسرطان من مركبات الفلافونويد والنانوفلافونويد على خطين مختلفين من الخلايا السرطانية وكذلك خطوط الخلايا السليمة باستخدام اختبار MTT. تم استخدام تجزئة الحمض النووي وتقنية تلوين الخلايا بالصبغة المزدوجة AO / EtBr لفحص علامات موت الخلايا المبرمج. لتحديد تشتت دورة الخلية ، تم استخدام قياس التدفق الخلوي ، وأظهرت النتائج أن كميات الفلافونويد والنانوفلافونويد لها نشاطا ساما وفعالا ضد خطوط خلايا سرطان الثدي والبروستات. بالإضافة إلى ذلك ، تم ربط إيقاف دورة الخلية في مرحلة G0 / G1 بموت الخلايا المبرمج لخطوط الخلايا التي يسببها الفلافونويد والنانوفلافونويد. وفقًا لهذه النتائج ، تمنع مركبات الفلافونويد والنانوفلافونويد من تكاثر خطوط الخلايا السرطانية ، مما يؤدي إلى توقف دورة الخلية وتحفيز موت الخلايا المبرمج. تشير النتائج المتاحة إلى أن مركب الفلافونويد والنانوفلافونويد سيمثل نهجًا علاجيًا واعدًا لعلاج الخلايا السرطانية من الأنواع الأخرى.

Damping properties and mechanism of aluminum matrix composites reinforced with glass cenospheres

The damping properties were improved by preparing Al matrix composites reinforced with glass cenospheres through the pressure infiltration method. Transmission electron microscopy and scanning electron microscopy were employed to characterize the microstructure of the composites. The low-frequency damping properties were examined by using a dynamic mechanical thermal analyzer, aiming at exploring the changing trend of damping capacity with strain, temperature, and frequency. The findings demonstrated that the damping value rose as temperature and strain increased, with a maximum value of 0.15. Additionally, the damping value decreased when the frequency increased. Dislocation damping under strain and interfacial damping under temperature served as the two primary damping mechanisms. The increase in the density of dislocation strong pinning points following heat treatment reduced the damping value, which was attributed to the heat treatment enhancement of the interfacial bonding force of the composites.

Nexus approach: Valorising underrated lignocellulosic waste biomass through conjugated magnetic nanoparticles for thermal energy storage facilities

Abstract Converting waste to a value-added material is a fortune. At the meantime highlighting the utilization of renewable solar energy as an inconsumable energy cradle is a future prospect to overcome the energy shortage and crisis. In this regard, storing the solar energy for the use at the off-sun periods is essential. Introducing sawdust waste for thermal energy storage system is a ecological chance. Treated sawdust was mixed with the environmentally benign magnetite to be a composite and mixed with technical grade paraffin base PCM. The composite was characterized through X-ray diffractometer (XRD), Transmission electron microscopy, TEM analysis and Scanning Electron Microscope, SEM (augmented with Dispersive X-Ray Analysis, EDX). Micrographs and Fourier transform infrared (FTIR) exhibited that the prepared composite substance is well prepared. The sawdust is subjected to the PCM system in various mass % ranged from 0.5 to 4%. Subsequently, the thermal system outline is presented and compared. The experimental data revealed that the addition of 2.0 weight percentage of the PCM of composite material showed the superior system performance. The system is achieved a heat gained reached to 82 kJ/min in comparison to 7 kJ/min for the 2.0% WCM-PCM and pristine PCM, respectively. Thereby, the current investigation is introducing the waste sawdust as an energy storage enhancement system that could be applied in heating application systems.

Mechanical properties and damage characterization of 310S steel using laser ultrasonic inspection under extreme temperature condition

Abstract To evaluate the mechanical properties of 310S stainless steel under extreme working conditions, and realize the damage characterization function, in this study, the longitudinal wave and Rayleigh wave of materials are measured by the method of coaxial inspection on reverse surface and ipsilateral ectopic inspection, respectively, and surface cracks and internal voids are detected by the scanning laser source technology and transmission scanning detection, respectively. The detection methods are designed based on the energy distribution characteristics of Rayleigh wave and longitudinal waves in laser ultrasound. The laser ultrasonic detection systems coupled with a temperature loading device (high temperature: vacuum chamber; low temperature: refrigerating chamber) developed by the laboratory enable on-site monitoring of laser ultrasonic technology in harsh environments. Experimental results demonstrate that the error in mechanical properties (elastic modulus, shear modulus, Poisson ratio) is less than 5% over a wide temperature range (-180-1000°C). At 1000°C, surface cracks wider than 0.5mm and deeper than 1.9mm as well as internal hole defects larger than 1.0mm can be detected with an error rate below 5%.

Electrochemical evaluation of fenitrothion organophosphate pesticide in food samples: Novel tetra trifluoromethyl carboxamide zinc (II) macrocyclic complex composite with multiwalled carbon nanotubes

This study presents the development of a groundbreaking electrochemical sensor for detecting fenitrothion (FNT) using a multi-walled carbon nanotubes (MWCNTs) and a newly synthesized zinc (II) tetra trifluoromethyl carboxamide phthalocyanine (ZnTFMPCAPc). The ZnTFMPCAPc was synthesized concluding a two-step mechanical and magnetic stirring method, and the ensuing ZnTFMPCAPc@MWCNTs underwent comprehensive characterization employing X-ray diffraction (XRD), Ultraviolet visible spectroscopy (UV–Vis), mass spectrum, Fourier transform infrared spectroscopy (FT-IR), Thermo-gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), Mass, Raman spectra, Transmission Electron Microscopy (TEM) and scanning electron microscope (SEM). Cyclic voltammetry (CV) analysis demonstrated a remarkable seven-fold improvement in electrochemical signals with ZnTFMPCAPc@MWCNTs on modified glassy carbon electrode (GCE) compared to a bare and modified GCE. The correlation between peak current and FNT concentration (in the range of 10–310 μmol) was established. The estimated limits of detection (LOD) and quantification (LOQ) were determined to be 1.358 nmol and 4.075 nmol respectively. The ZnTFMPCAPc@MWCNTs/GCE sensor was successfully evaluated by quantifying FNT in tomatoes, grapes, paddy grains, and potato extracts, resulting in satisfactory results. Detecting fenitrothion is crucial due to its widespread use as a pesticide, which can result in environmental contamination and pose health risks. Regular monitoring is essential for protecting food and water supplies, preserving ecosystems, and ensuring compliance with regulations to prevent long-term environmental damage.