29,185 results on '"chemical properties"'
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2. Electronic structure of zaykovite Rh3Se4, prediction, and analysis of physical properties of related materials: Pd3Se4, Ir3Se4, and Pt3Se4.
- Author
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Taran, Leonid S., Eremeev, Sergey V., and Streltsov, Sergey V.
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HEAT of formation ,ELECTRONIC structure ,ELECTRONIC spectra ,TRANSITION metals ,CHEMICAL properties - Abstract
In this work, we explore the electronic properties and chemical bonding in the recently discovered mineral zaykovite, the first natural rhodium selenide Rh
3 Se4 . We comprehensively studied the bulk electronic structure, hybridization of rhodium and selenium orbitals, and the influence of spin–orbit interaction on the electronic spectrum, as well as inspected its topological properties. In addition, we investigated the surface electronic structure of zaykovite and revealed the anisotropic Rashba-type spin splitting in the surface states. In addition, using calculations of the phonon spectra and enthalpy of formation, we predicted the family of similar selenides based on other 4d and 5d transition metals such as Ir, Pd, and Pt. The structural and electronic properties of these materials are discussed. [ABSTRACT FROM AUTHOR]- Published
- 2024
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3. Unraveling the cation dependent carrier cooling and transient mobility in lead-free A3Sb2I9 perovskites.
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Shukla, Ayushi, Kaur, Gurpreet, Babu, K. Justice, Bhatt, Himanshu, and Ghosh, Hirendra N.
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RUBIDIUM , *PEROVSKITE , *PUMP probe spectroscopy , *HOT carriers , *CHEMICAL engineering , *CARRIER density , *OPTICAL spectroscopy , *CHEMICAL properties - Abstract
Lead halide perovskites (LHPs) have gained prominence for their exceptional photophysical properties, holding promise for applications in high-end optoelectronic devices. However, the presence of lead is one of the major obstacles to the commercialization of LHPs in the field of photovoltaics. To address this, researchers have explored environment friendly lead-free perovskite solar cells by investigating non-toxic perovskite materials. This study explores the enhancement of photophysical properties through chemical engineering, specifically cation exchange, focusing on the crucial photophysical process of hot carrier cooling. Employing femtosecond transient absorption spectroscopy and optical pump terahertz probe spectroscopy, we have probed the carrier relaxation dynamics in A3Sb2I9 with cesium and rubidium cations. This study unravels that the carrier relaxation is found to be slower in Rb3Sb2I9; along with this, the transient mobility decay is found to be retarded. Overall, this study suggests that an antimony-based Rb3Sb2I9 perovskite could be a substantial lead-free perovskite in photovoltaics. These findings provide valuable insights into cation engineering strategies, aiming to improve the overall performance of lead-free-based photovoltaic devices. [ABSTRACT FROM AUTHOR]
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- 2024
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4. The effect of ligands on the size distribution of copper nanoclusters: Insights from molecular dynamics simulations.
- Author
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Elishav, Oren, Blumer, Ofir, Vanderlick, T. Kyle, and Hirshberg, Barak
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MOLECULAR dynamics , *COPPER , *DENSITY functional theory , *LIGANDS (Chemistry) , *CHEMICAL properties - Abstract
Controlling the size distribution in the nucleation of copper particles is crucial for achieving nanocrystals with desired physical and chemical properties. However, their synthesis involves a complex system of solvents, ligands, and copper precursors with intertwining effects on the size of the nanoclusters. We combine molecular dynamics simulations and density functional theory calculations to provide insights into the nucleation mechanism in the presence of a triphenyl phosphite ligand. We identify the crucial role of the strength of the metal–phosphine interaction in inhibiting the cluster's growth. We demonstrate computationally several practical routes to fine-tune the interaction strength by modifying the side groups of the additive. Our work provides molecular insights into the complex nucleation process of protected copper nanocrystals, which can assist in controlling their size distribution and, eventually, their morphology. [ABSTRACT FROM AUTHOR]
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- 2024
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5. Relative cooperativity in neutral and charged molecular clusters using QM/MM calculations.
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Nochebuena, Jorge, Liu, Shubin, and Cisneros, G. Andrés
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MOLECULAR clusters , *CHEMICAL structure , *DENSITY functional theory , *CHEMICAL properties , *ELECTRONIC structure , *INTERMOLECULAR interactions - Abstract
QM/MM methods have been used to study electronic structure properties and chemical reactivity in complex molecular systems where direct electronic structure calculations are not feasible. In our previous work, we showed that non-polarizable force fields, by design, describe intermolecular interactions through pairwise interactions, overlooking many-body interactions involving three or more particles. In contrast, polarizable force fields account partially for many-body effects through polarization, but still handle van der Waals and permanent electrostatic interactions pairwise. We showed that despite those limitations, polarizable and non-polarizable force fields can reproduce relative cooperativity achieved using density functional theory due to error compensation mechanisms. In this contribution, we assess the performance of QM/MM methods in reproducing these phenomena. Our study highlights the significance of the QM region size and force field choice in QM/MM calculations, emphasizing the importance of parameter validation to obtain accurate interaction energy predictions. [ABSTRACT FROM AUTHOR]
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- 2024
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6. Insight into the interaction of host–guest structures for pyrrole-based metal compounds and C70.
- Author
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Li, Mengyang, Zhou, Yuqi, Wei, Bing, Wei, Qun, Yuan, Kun, and Zhao, Yaoxiao
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METAL compounds , *FULLERENES , *DENSITY functional theory , *CHEMICAL properties , *BINDING energy - Abstract
This study focuses on the recognition and isolation of fullerenes, which are crucial for further exploration of their physical and chemical properties. Our goal is to investigate the potential recognition of the D5h–C70 fullerene using crown-shaped metal compositions through density functional theory calculations. We assess the effectiveness of fullerene C70 recognition by studying the binding energy. Additionally, various analyses were conducted, including natural bond order charge analysis and reduced density gradient analysis, to understand the interaction mechanism between the host and guest molecules. These investigations provide valuable insights into the nature of the interaction and the stability of the host–guest system. To facilitate the release of the fullerene guest molecule, the vis–NIR spectra were simulated for the host–guest structures. This analysis offers guidance on the specific wavelengths that can be utilized to release the fullerene guest from the host–guest structures. Overall, this work proposes a new strategy for the effective recognition of various fullerene molecules and their subsequent release from host–guest systems. These findings could potentially be applied in assemblies involving fullerenes, advancing their practical applications. [ABSTRACT FROM AUTHOR]
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- 2024
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7. Insight into the interaction of host–guest structures for pyrrole-based metal compounds and C70.
- Author
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Li, Mengyang, Zhou, Yuqi, Wei, Bing, Wei, Qun, Yuan, Kun, and Zhao, Yaoxiao
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METAL compounds ,FULLERENES ,DENSITY functional theory ,CHEMICAL properties ,BINDING energy - Abstract
This study focuses on the recognition and isolation of fullerenes, which are crucial for further exploration of their physical and chemical properties. Our goal is to investigate the potential recognition of the D
5h –C70 fullerene using crown-shaped metal compositions through density functional theory calculations. We assess the effectiveness of fullerene C70 recognition by studying the binding energy. Additionally, various analyses were conducted, including natural bond order charge analysis and reduced density gradient analysis, to understand the interaction mechanism between the host and guest molecules. These investigations provide valuable insights into the nature of the interaction and the stability of the host–guest system. To facilitate the release of the fullerene guest molecule, the vis–NIR spectra were simulated for the host–guest structures. This analysis offers guidance on the specific wavelengths that can be utilized to release the fullerene guest from the host–guest structures. Overall, this work proposes a new strategy for the effective recognition of various fullerene molecules and their subsequent release from host–guest systems. These findings could potentially be applied in assemblies involving fullerenes, advancing their practical applications. [ABSTRACT FROM AUTHOR]- Published
- 2024
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8. Investigation of the large-signal electromechanical behavior of ferroelectric HfO2–CeO2 thin films prepared by chemical solution deposition.
- Author
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Lübben, Jan, Berg, Fenja, and Böttger, Ulrich
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FERROELECTRIC thin films , *CHEMICAL solution deposition , *PIEZOELECTRIC thin films , *FERROELECTRIC materials , *CHEMICAL properties , *ELECTRIC fields - Abstract
In this work, the piezoelectric properties of chemical solution deposition derived ferroelectric HfO2–CeO2 thin films deposited on platinized silicon substrates are investigated. Large-signal strain-field measurements show an effective piezoelectric coefficient of approximately d 33 , eff = 12.7 pm / V for 17 mol. % cerium under bipolar excitation and d 33 , eff = 8 pm / V under unipolar excitation. Progressive bipolar electric field cycling leads to a reduction in the overall field induced strain although no fatigue with regards to the polarization is observed. To explain this, we propose a model explanation based on changes in the polarization reversal pathway from a primarily ferroelastic, i.e., 90 ° domain wall mediated switching, to a 180 ° type switching. Furthermore, unipolar strain-field measurements reveal a negative intrinsic piezoelectric coefficient in the absence of any ferroelastic contribution, confirming theoretical predictions. The results suggest that the ferroelastic contribution to the field-induced strain needs to be stabilized in Hafnia-based ferroelectric materials to make them more feasible for micro-electromechanical systems. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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9. Enhanced ferromagnetic properties achieved by F-doping in BaFe1−xMnxO3−δ.
- Author
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Huang, Jun, Yang, Jiwen, Wang, Yangkai, Zhang, Jian, Wang, Jianlin, Fu, Zhengping, Peng, Ranran, and Lu, Yalin
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REMANENCE , *ELECTRON configuration , *MAGNETIC materials , *CRYSTAL structure , *CHEMICAL properties - Abstract
Tailoring the crystal structure, spin, and charge state of perovskite oxides through fluorine ion doping is an attractive and effective strategy, which could significantly modify the physical and chemical properties of base oxides. Here, BaFe1−xMnxO3−δ (x = 0, 0.1, 0.2, 0.3) and BaFe1−xMnxO2.9−δF0.1 (x = 0.1, 0.2, 0.3), belonging to 6H-type BaFeO3−δ, are prepared and investigated to evaluate the impact of F− doping. The distortion of crystal structure and the reduced average valence of Mn and Fe confirm the preference for F− substitution in the hexagonal layer, which are found as the key factors for the improved magnetic properties, including ferromagnetic ordering temperature, coercive force, and remanent magnetization. Moreover, the valence reduction of B-site ions and the increased resistance distinctly indicate the expense of electron hole via fluorine doping. This work describes the adjustment of crystal structure, electronic configuration, and ferromagnetic performance by simple F− doping, which provides a prospect for practical magnetic materials. [ABSTRACT FROM AUTHOR]
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- 2024
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10. Enhanced ferromagnetic properties achieved by F-doping in BaFe1−xMnxO3−δ.
- Author
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Huang, Jun, Yang, Jiwen, Wang, Yangkai, Zhang, Jian, Wang, Jianlin, Fu, Zhengping, Peng, Ranran, and Lu, Yalin
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REMANENCE ,ELECTRON configuration ,MAGNETIC materials ,CRYSTAL structure ,CHEMICAL properties - Abstract
Tailoring the crystal structure, spin, and charge state of perovskite oxides through fluorine ion doping is an attractive and effective strategy, which could significantly modify the physical and chemical properties of base oxides. Here, BaFe
1−x Mnx O3−δ (x = 0, 0.1, 0.2, 0.3) and BaFe1−x Mnx O2.9−δ F0.1 (x = 0.1, 0.2, 0.3), belonging to 6H-type BaFeO3−δ , are prepared and investigated to evaluate the impact of F− doping. The distortion of crystal structure and the reduced average valence of Mn and Fe confirm the preference for F− substitution in the hexagonal layer, which are found as the key factors for the improved magnetic properties, including ferromagnetic ordering temperature, coercive force, and remanent magnetization. Moreover, the valence reduction of B-site ions and the increased resistance distinctly indicate the expense of electron hole via fluorine doping. This work describes the adjustment of crystal structure, electronic configuration, and ferromagnetic performance by simple F− doping, which provides a prospect for practical magnetic materials. [ABSTRACT FROM AUTHOR]- Published
- 2024
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11. Tuning the electronic and optical properties of small organic acenedithiophene molecular crystals for photovoltaic applications: First principles calculations.
- Author
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Lazaar, Koussai, Gueddida, Saber, Said, Moncef, and Lebègue, Sébastien
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MOLECULAR crystals , *OPTICAL properties , *SEMICONDUCTORS , *DENSITY functional theory , *CHEMICAL properties , *ATOMS , *CHARGE carrier mobility , *ORGANIC semiconductors - Abstract
Periodic density functional theory was employed to investigate the impact of chemical modifications on the properties of π-conjugated acenedithiophene molecular crystals. Here, we highlight the importance of the β-methylthionation effect, the position of the sulfur atoms of the thiacycle group and their size, and the number of central benzene rings in the chemical modification strategy. Our results show that the introduction of the methylthio groups at the β-positions of the thiophene and the additional benzene ring at the center of the BDT crystal structure are a promising strategy to improve the performance of organic semiconductors, as observed experimentally. We found that β-MT-ADT exhibits large charge carrier mobility, which is in good agreement with the experimental results and comparable to that of rubrene. In addition, the electronic and optical properties of these ambipolar materials suggest promising performances with β-MT-ADT > ADT > β -MT-NDT > NDT > BEDT-BDT > β -MT-BDT > BDT. Moreover, functionalization with thiacycle-fused sulfur atoms of different sizes and numbers improve the properties of BDT but is still less efficient than the methylthionation effect. Overall, our findings suggest a promising molecular modification strategy for possibly high performance ambipolar organic semiconducting materials. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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12. Conformations of borneol and isoborneol in the gas phase: Their monomers and microsolvation clusters.
- Author
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Pinacho, Pablo, Quesada-Moreno, María Mar, and Schnell, Melanie
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MICROWAVE spectroscopy , *MOLECULAR structure , *CHEMICAL properties , *FOURIER transform spectroscopy , *MONOMERS , *HYDROGEN bonding , *DIMETHYL sulfoxide - Abstract
Borneol is a natural monoterpene with significant applications in various industries, including medicine and perfumery. It presents several diastereomers with different physical and chemical properties, influenced by their unique structures and interactions with molecular receptors. However, a complete description of its inherent structure and solvent interactions remains elusive. Here, we report a detailed investigation of the gas-phase experimental structures of borneol and isoborneol, along with the description of their microsolvation complexes with the common solvents water and dimethyl sulfoxide. The molecules and complexes were studied using chirped-pulse Fourier transform microwave spectroscopy coupled to a supersonic expansion source. Although three rotamers are potentially populated under the conditions of the supersonic expansion, only one of them was observed for each monomer. The examination of the monohydrated complexes revealed structures stabilized by hydrogen bonds and non-covalent C–H⋯O interactions, with water as the hydrogen bond donor. Interestingly, in the clusters with dimethyl sulfoxide, borneol and isoborneol change their roles acting as donors. We further identified a higher-energy rotamer of the borneol monomer in one of the complexes with dimethyl sulfoxide, while that rotamer was missing in the experiment for the monomer. This observation is not common and highlights a specific position in borneol especially favorable for forming stable complexes, which could have implications in the understanding of the unique physical and chemical properties of the diastereomers. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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13. A Snapshot of Lead in Consumer Products Across Four US Jurisdictions
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Porterfield, Kate, Hore, Paromita, Whittaker, Stephen G., Fellows, Katie M., Mohllajee, Anshu, Azimi-Gaylon, Shakoora, Watson, Berna, Grant, Isabel, and Fuller, Richard
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Jurisdiction -- Evaluation ,Consumer goods -- Chemical properties ,Lead -- Health aspects ,Public health administration -- Evaluation ,Environmental issues ,Health ,Evaluation ,Chemical properties ,Health aspects - Abstract
BACKGROUND: Following the removal of lead from gasoline, paint and pipes were thought to be the main sources of lead exposure in the United States. However, consumer products, such as certain spices, ceramic and metal cookware, traditional health remedies, and cultural powders, are increasingly recognized as important sources of lead exposure across the United States. OBJECTIVE: This paper reviews data from four US jurisdictions that conduct in-home investigations for children with elevated blood lead levels (BLLs) to examine the prevalence of lead exposures associated with consumer products, in comparison with housing-related sources. METHODS: Authors reviewed investigation data (2010-2021) provided by California, Oregon, New York City, and King County, Washington, and compared the extent of lead exposures associated with housing-related vs. consumer products--related sources. DISCUSSION:The proportion of investigations identifying consumer products--related sources of lead exposure varied by jurisdiction (range: 15%-38%). A review of US CDC and US FDA alerts and New York City data indicates that these types of lead-containing products are often sourced internationally, with many hand carried into the United States during travel. Based on surveillance data, we believe that US immigrant and refugee communities are at an increased risk for lead exposures associated with these products. To engage health authorities, there is a need for evidentiary data. We recommend implementing a national product surveillance database systematically tracking data on consumer products tested by childhood lead poisoning prevention programs. The data repository should be centralized and accessible to all global stakeholders, including researchers and governmental and nongovernmental agencies, who can use these data to inform investigations. Effectively identifying and addressing the availability of lead-containing consumer products at their source can focus resources on primary prevention, reducing lead exposures for users abroad and in the United States. https://doi.org/10.1289/EHP14336, Introduction Blood lead levels (BLLs) of children in the United States have declined significantly since the 1970s. Based on the National Health and Nutrition Examination Survey (NHANES), there was a [...]
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- 2024
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14. Coordination-induced bond weakening in NiC3: An experimental and theoretical investigation.
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Liu, Zhiling, Yan, Yonghong, Yang, Yufeng, Zhang, Fuqiang, Jia, Jianfeng, and Li, Ya
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TRANSITION metal carbides , *PHOTOELECTRONS , *CHEMICAL properties , *SPECTRAL imaging , *DENSITY functional theory , *ANGULAR distribution (Nuclear physics) - Abstract
Mass-selected photoelectron velocity-map imaging spectroscopy in conjunction with the density functional theory calculations was employed to investigate the geometrical and chemical bonding properties of NiC3−/0. Both the photoelectron spectrum and photoelectron angular distribution were measured from the spectra, yielding useful geometrical and electronic information about NiC3−/0. The complementary theoretical calculations suggest that the linear and fan-like structures were both populated experimentally in the cluster beam. Further comparative study on the synergistic donor–acceptor interactions in both isomers revealed the side-on coordination-induced bond weakening in the fan-like isomer as compared to the linear isomer. These findings will shed light on the structure-dependent reactivity of transition metal carbides. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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15. Chemical bonding properties of liquid methane under high-density conditions.
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Murayama, D., Ohmura, S., Kodama, R., and Ozaki, N.
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CHEMICAL bonds , *CHEMICAL properties , *ELECTRONIC density of states , *ELECTRON distribution , *TRANSITION metals , *ELECTRON density , *OXYGEN carriers - Abstract
We present the chemical bonding and electronic properties of liquid methane at temperatures from 2000 to 4000 K and high densities of up to 3.0 g/cm3, calculated using ab initio molecular dynamics simulations in combination with the Mulliken population analysis. Bond-overlap populations and pair distribution functions are studied to investigate the evolution of electron delocalization accompanying atomic structure change as the density is increased. In addition, we also investigated the bandgap energy, electronic density of states, and spatial distribution of electron density. We observed that molecular hydrogen and C‒C bonds are formed after methane dissociates, and then the system undergoes a nonmetal–metal transition coinciding with hydrogen being transformed from the molecular to the atomic state. The C‒C bonds in the system retain covalent character, even at the highest density of 3.0 g/cm3. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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16. One-step synthesis of onion carbon with tunable particle sizes and its performance as a lubrication agent.
- Author
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Hu, Meng, Ji, Shutong, Lu, Hang, Ma, Mengdong, Hua, Jing, Li, Penghui, Shi, Lu, He, Julong, and Ding, Jianning
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CARBON films , *CHEMICAL structure , *STAINLESS steel , *CHEMICAL properties , *TEMPERATURE distribution - Abstract
Due to the unique structures and superior chemical and physical properties, onion carbon holds great appeal for various applications, such as lubrication, energy storage and catalysis. However, conventional synthesis methods for onion carbon are often complex, resulting in products of low purity and quantity. Here we report the one-step combustion synthesis of onion carbon with high purity and tunable particle size by employing naphthalene as the precursor, and investigated the effect of combustion temperatures on the formation mechanism of onion carbon, leading to the achievement of controlled preparation of onion carbon. The size of synthesized onion carbon particles ranges from 50 to 190 nm, which increases with the synthesis temperature and shows a wider distribution at higher temperatures. Owing to the abundant oxygen-containing functional groups, as-synthesized onion carbon exhibits prolonged stability and solubility in organic solvents such as ethanol and glycerol. Furthermore, we tested the friction performance of stainless steel coated with onion carbon films by ball-on-disk mode on the upper surface with different loads and sliding speeds. Deposited onion carbon film improved the friction performance of stainless steel at high load and sliding speed. [Display omitted] [ABSTRACT FROM AUTHOR]
- Published
- 2024
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17. Experimental investigation on magnetorheological shear thickening polishing characteristics for SiC substrate.
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Ma, Xifeng, Tian, Yebing, Qian, Cheng, Ma, Zhen, Ahmad, Shadab, Li, Ling, and Fan, Zenghua
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CHEMICAL properties , *SILICON surfaces , *SURFACE roughness , *MAGNETORHEOLOGY , *ELECTROMAGNETIC induction - Abstract
Silicon carbide (SiC) substrates are widely used in semiconductor and photoelectric applications due to excellent electrical and chemical properties. However, due to its inherent hard-brittle properties and chemical inertness, traditional polishing processes are facing great challenges to obtain excellent surface and subsurface quality for the SiC substrates. In this work, a novel polishing process i.e. magnetorheological shear thickening polishing (MRSTP) was proposed to explore the feasibility for the polishing of the SiC substrates. The MRSTP experiments were conducted using multiple magnetic-pole-coupled tools. The magnetic field characteristics of the polishing area were investigated via finite element simulation and actual measurements. The magnetic-pole-coupled tool was capable of generating high magnetic induction strength in the polishing area. The MRSTP medium was designed and prepared. The media were formed magnetic brushes by the excited magnetic field. The MRSTP experiments were conducted to investigate the effects of processing parameters on the polished surface roughness. The optimum process parameters were determined as the spindle rotational speed of 700 rpm, the feed rate of 600 mm/min, the work gap of 0.5 mm and MRSTP media CIPs particle size of 100 μm. The surface roughness of the workpieces was improved from initial 1.414 μm to 27.6 nm. It is verified that the MRSTP is the feasible ultraprecision polishing process for the SiC substrates. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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18. Exploring the ambient metastability of yttrium substituted Bi2O3 electrolyte materials.
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Kiefer, Mathias A., Masina, Sikhumbuzo M., Billing, Caren, Olds, Daniel, and Billing, David G.
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SOLID electrolytes , *BISMUTH trioxide , *BISMUTH oxides , *CHEMICAL properties , *BISMUTH - Abstract
The phase stability of (Bi 1-x Y x) 2 O 3 (0.1 ≤ x ≤ 0.275) solid state electrolytes synthesized using the sol-gel method was investigated over prolonged periods under ambient conditions. The cubic polymorph was found to be metastable under ambient conditions, particularly for 0.1 ≤ x ≤ 0.15 where significant cubic-to-tetragonal transformation occurred. Spontaneous minor formation of both the rhombohedral polymorph and a bismuth subcarbonate phase was evident across the doping range but with varied reproducibility. Aging was significantly more prevalent for samples that had only been calcined (at 450 °C) as compared to those that were subsequently annealed (at 750 °C). The more highly substituted annealed materials (0.25 ≤ x ≤ 0.275) were initially phase pure cubic and far more stable, yet some rhombohedral and bismuth subcarbonate phase formation was also seen. Although the initial source of carbon which leads to the formation of the subcarbonate phase is not known at this stage, several suggestions are made. Pelletisation with additional sintering, as well as annealing powder samples under an inert atmosphere, was also shown to enhance the long-term phase stability characteristics of the cubic phase. This is the first longer term (over 2 years) ambient phase aging study of substituted bismuth oxides. [ABSTRACT FROM AUTHOR]
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- 2024
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19. The comprehensive utilization of mass and heat of hot blast furnace slag and coordinated disposal of chromium-containing sludge to prepare glass-ceramic.
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Niu, Yingying, Zheng, Feng, Liu, Yang, Yang, Yue, Yu, Tao, Wang, Zeyuan, Mao, Xiaodong, Zhen, Qiang, and Yu, Yi
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HAZARDOUS wastes , *VICKERS hardness , *THERMAL conductivity , *COMPRESSIVE strength , *CHEMICAL properties - Abstract
Currently in steel enterprises, the mass and heat of hot blast furnace slag (BFS) are not fully recovered, and the produced chrome-containing sludge (CCS) poses a significant threat to the ecological environment. In this work, CCS together with other ingredients is added into hot BFS to produce high value-added glass-ceramic (GC), after the mixed molten slag is cooled down. The obtained GC shows excellent physical and chemical properties (bulk density: 2.76 g cm−3, water absorption: 0.059 %, compressive strength: 78 MPa, Vickers hardness: 7.54 GPa, acid resistance: 98.63 %, alkali resistance: 99.84 %, thermal conductivity: 1.049 W m−1 °C−1, and thermal expansivity: 6.56 × 10−6 m m−1 °C−1). These excellent physical and chemical properties render the as-prepared GC a high value-added building material. In addition, the leaching concentrations of total Cr element and Cr(VI) in the as-prepared GC are 1.6 mg L−1 and 1.03 mg L−1, respectively, which are below the standard threshold for hazardous waste extraction toxicity. Compared with the traditional sintering method, the sensible heat of the hot BFS can be used as the thermal source in the molten slag cooling method, which can save a lot of energy. The use of hot BFS and CCS to produce high value-added GC not only fully utilizes the mass and heat of hot BFS but also fixes the Cr element in the CCS within the crystalline phase of GC, thereby eliminating the pollution of CCS to the environment. [Display omitted] [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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20. Synthesis, characterization and corrosive resistance of ZnO and ZrO2 coated TiO2 substrate prepared via polymeric method and microwave combustion.
- Author
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Gaber, A.A., Abd El-Hamid, H.K., Ngida, Rehab E.A., Sadek, H.E.H., and Khattab, R.M.
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SUBSTRATES (Materials science) , *CHEMICAL properties , *TITANIUM dioxide , *TRANSMISSION electron microscopy , *ZINC oxide - Abstract
The TiO 2 substrate coatings containing varied ZnO or ZrO 2 nanoparticles were made using the polymeric and microwave combustion methods and then thermally treated at various temperatures. Furthermore, before coating on the substrate, the produced nanoparticles undergo characterization and calcination to optimize the conditions for developing ZnO and ZrO 2 phases and track their composition. The X-ray diffraction method (XRD), transmission electron microscopy (TEM), and infrared analysis (IR) are used to characterize the calcined produced nanoparticles. After heat treatment at 1000 °C, the TiO 2 substrate is prepared. The produced coated substrate is studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared (IR), apparent porosity, bulk density, chemical corrosive properties and electrochemical measurement in 3.5 % NaCl and 1 M HCl solutions. The corrosion resistance of ZnO or ZrO 2 -covered TiO 2 substrate is ascertained by anticorrosive behaviors, which include weight loss, apparent porosity, corrosion rate, and SEM. The findings showed that 800 °C is the ideal temperature for preparing ZrO 2 -coated substrate, whereas 1000 °C is the perfect temperature for preparing ZnO-coated substrate. The microstructure reveals surface micro-cracks on the ZrO 2 -coated TiO 2 substrate. Good dispersion, homogeneity, and compaction were noted for the ZnO-coated substrate. Between 14 and 17 % of the ZnO-coated substrate and 20–21 % of the ZrO 2 -coated substrate, made via polymeric and microwave combustion techniques, had visible porosity when ZnO-coated samples exhibited greater corrosion resistance against NaCl media. In contrast, ZrO 2 -coated samples had much stronger anticorrosive qualities in HCl media than uncoated and Zn-coated samples. According to the electrochemical results, the ZnO-coated TiO 2 synthesized by polymeric technique at 1000 °C showed 99.86 % inhibitory efficiency against NaCl. An inhibitory efficiency of 94.4 % was observed in a ZrO 2 -coated TiO 2 substrate that was produced at 800 °C using a polymeric technique. [ABSTRACT FROM AUTHOR]
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- 2024
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21. Progress in phenanthroline-derived extractants for trivalent actinides and lanthanides separation: where to next?
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Yang, Xiaofan, Xu, Lei, Fang, Dong, Zhang, Anyun, and Xiao, Chengliang
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RADIOISOTOPES , *NUCLEAR energy , *NUCLEAR fuels , *CHEMICAL properties , *SPENT reactor fuels , *ENVIRONMENTAL risk - Abstract
Spent nuclear fuel (SNF) released from reactors possesses significant radioactivity, heat release properties, and high-value radioactive nuclides. Therefore, using chemical methods for reprocessing can enhance economic efficiency and reduce the potential environmental risks of nuclear energy. Due to the presence of relatively diffuse f-electrons, the chemical properties of trivalent lanthanides (Ln(III)) and actinides (An(III)) in SNF solutions are quite similar. Separation methods have several limitations, including poor separation efficiency and the need for multiple stripping agents. The use of novel multi-dental phenanthroline-derived extractants with nitrogen donor atoms to effectively separate An(III) over Ln(III) has been widely accepted. This review first introduces the development history of phenanthroline-derived extractants for extraction and complexation with An(III) over Ln(III). Then, based on structural differences, these extractants are classified into four categories: nitrogen-coordinated, N,O-hybrid coordinated, highly preorganized structure, and unsymmetric structure. Each category's design principles, extraction, and separation performance as well as their advantages and disadvantages are discussed. Finally, we have summarized and compared the unique characteristics of the existing extractants and provided an outlook. This work may offer a reliable reference for the precise identification and selective separation between An(III) and Ln(III), and point the way for future development and exploration. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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22. A short review of carbon dots-based composites as advanced electrocatalysis.
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Li, Tianze, Dong, Yuanyuan, Zhang, Jianjiao, and Su, Yewenqing
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OXYGEN evolution reactions , *CARBON dioxide reduction , *HYDROGEN evolution reactions , *MATERIALS science , *CHEMICAL properties - Abstract
Carbon dots (CDs) are a type of carbon-based nanomaterial that has gained a lot of attention in the field of electrochemical catalysis. They have unique physical and chemical properties, such as high specific surface area, defects, heteroatom doping ability, and functional groups on their surface. These properties make them particularly effective in electrocatalysis, including hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), and carbon dioxide reduction (CO 2 RR). This review summarizes various methods for the preparation of CDs, including top-down methods and bottom-up methods, and analyzes their structure and properties in detail. It also delves into the role of CDs and their composites in specific electrocatalytic reactions, as well as the technical challenges they face in practical applications. Looking forward to the future, with the continuous progress of material science, nanotechnology and electrochemical theory, the potential applications of CDs and their composites in electrocatalysis are expected to be further expanded. • The preparation methods, structures and properties of CDs are introduced. • CDs are summarized as electrocatalysts for HER, OER, ORR and CO 2 RR. • The challenges of CDs in the field of electrocatalysis are summarized. [ABSTRACT FROM AUTHOR]
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- 2024
- Full Text
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23. Zinc‐Ion Battery Chemistries Enabled by Regulating Electrolyte Solvation Structure.
- Author
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Deng, Wenjing, Li, Ge, and Wang, Xiaolei
- Subjects
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AQUEOUS electrolytes , *ALTERNATIVE fuels , *STORAGE batteries , *ENERGY storage , *CHEMICAL properties - Abstract
Designing next‐generation alternative energy storage devices that feature high safety, low cost, and long operation lifespan is of the utmost importance for future wide range of applications. Aqueous zinc‐ion batteries play a vital part in promoting the development of portability, sustainability, and diversification of rechargeable battery systems. Based on the theory of electrolyte solvation chemistry, deep understanding of interaction between electrolyte components and their impact on the chemical properties has achieved a series of research progress. Analyzing the solvation shell of electrolyte or structure–performance relationship, and establishing more stable and high‐energy battery chemistries are inevitable requirements to suppress the electrolyte–electrode interphase side reaction and realize the functional use of zinc‐ion batteries. In this critical review, the attempt is to overview the current comprehension regarding the electrolyte solvation structure in zinc battery technology. Advanced methodology toward the interactions between zinc cations, solvent molecules, and anions in zinc aqueous electrolytes and the general rules for electrolyte design from the atomic level are summarized. Methods for viable solvation modification are then introduced regarding overcoming the remained challenges for transferring the laboratory results to next‐generation practical applications. Possible research direction with the aim of investigating the ultimate choice for future high‐performance electrolyte solvation construction is also outlined. [ABSTRACT FROM AUTHOR]
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- 2024
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24. Short-term tank culture of <italic>Gracilariopsis heteroclada</italic> at high salinities improves agar quality.
- Author
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Endoma, Leonilo F. Jr., Monsale, Duke R., Borlongan, Iris Ann G., Gaya, Hazel Coleen G., Santacera, Pearl Aljean S., and Yap, Encarnacion Emilia S.
- Subjects
- *
INFRARED spectra , *CHEMICAL properties , *AGAR , *SALINITY , *POLYSACCHARIDES - Abstract
Agar, a phycocolloid naturally extracted from
Gracilariopsis heteroclada is strongly influenced by salinity. Wild stocks ofG. heteroclada were exposed to varying salinities (20, 30, 40, 50, 60) for 6 days, and subsequently processed for agar extraction using 5 % NaOH. The extracted agar was evaluated regarding yield, gel rheology, colour composition, chemical properties, and infrared spectra. Results highlighted that hypersaline conditions (salinity 50) could produce high agar yield (4.77 %) and viscosity (10.67 mPa s), while agar samples at salinity 40 exhibited gels with high cohesiveness (6.35 mm), gel breaking strength (3.01 N), and gel strength (390.61 g cm−2) while having a rather high 3,6-anhydrogalactose content (7.49 %). All samples exhibited FTIR signature peaks at 930 cm−1, confirming the identity of extracted agar fromG. heteroclada . Exposure at increasing hypersalinity increased the sulphate levels of agar fromG. heteroclada , which implies synthesis of sulphated polysaccharides. Moreover, high 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activities were obtained in acid hydrolysed agars at salinities of 40 (74.09 %) and 50 (75.57 %), suggesting thatG. heteroclada agars from hypersaline conditions potentially offer antioxidative roles beyond its traditional food use. [ABSTRACT FROM AUTHOR]- Published
- 2024
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25. Chelator‐Assisted Precipitation‐Based Separation of the Rare Earth Elements Neodymium and Dysprosium from Aqueous Solutions.
- Author
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Gao, Yangyang, Licup, Gerra L., Bigham, Nicholas P., Cantu, David C., and Wilson, Justin J.
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RARE earth metals , *STABILITY constants , *CHEMICAL properties , *DYSPROSIUM , *CLEAN energy , *BINDING energy - Abstract
The rare earth elements (REEs) are critical resources for many clean energy technologies, but are difficult to obtain in their elementally pure forms because of their nearly identical chemical properties. Here, an analogue of macropa, G‐macropa, was synthesized and employed for an aqueous precipitation‐based separation of Nd3+ and Dy3+. G‐macropa maintains the same thermodynamic preference for the large REEs as macropa, but shows smaller thermodynamic stability constants. Molecular dynamics studies demonstrate that the binding affinity differences of these chelators for Nd3+ and Dy3+ is a consequence of the presence or absence of an inner‐sphere water molecule, which alters the donor strength of the macrocyclic ethers. Leveraging the small REE affinity of G‐macropa, we demonstrate that within aqueous solutions of Nd3+, Dy3+, and G‐macropa, the addition of HCO3− selectively precipitates Dy2(CO3)3, leaving the Nd3+−G‐macropa complex in solution. With this method, remarkably high separation factors of 841 and 741 are achieved for 50 : 50 and 75 : 25 mixtures. Further studies involving Nd3+:Dy3+ ratios of 95 : 5 in authentic magnet waste also afford an efficient separation as well. Lastly, G‐macropa is recovered via crystallization with HCl and used for subsequent extractions, demonstrating its good recyclability. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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26. Synthesis of polymeric microcapsules filled with castor oil to enhance tribological properties in epoxy resin.
- Author
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Fernandes, Mariza, Souza, Juliana, Santos, Ana Leticia, Medeiros, Pamella, Bomio, Mauricio, and Costa, Maria
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- *
CASTOR oil , *FOURIER transform infrared spectroscopy , *SCANNING electron microscopes , *COMPOSITE materials , *CHEMICAL properties - Abstract
The addition of microcapsules (MCs) to a polymer matrix has been gaining attention because it facilitates the attainment of composite materials with better mechanical, chemical and functional properties that enhance its tribological properties. In this work, poly (urea formaldehyde) (PUF) microcapsules filled with castor oil were synthesized using an in situ polymerization method and then added to the epoxy matrix at mass percentages of 2.5%, 5% and 10%. Spherical microcapsules were obtained with the desired composition, confirmed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) images. The surface of the composites was analyzed using the roughness parameters Ra, Rq, Rz, Rsk and Rku. The preliminary tribological properties were evaluated using tests with a pin-on-disk configuration. After the tribological tests, the wear track was characterized using SEM images. There was a reduction of approximately 50% in the coefficient of friction of the composites studied and the specimen with 2.5% microcapsules had the best self-lubricating performance, considering the characterizations of roughness and track sinking. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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27. Hybridization of magnetic MOF composites with 3D terminal carboxyl hyperbranched polymers for dye wastewater treatment.
- Author
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Zhao, Yuan, Liu, Yinhua, Shen, Ling, Liu, Junhui, Zhu, Mengcheng, Wang, Xuan, Zhao, Pengju, Xu, Hang, and Fan, Qianlong
- Subjects
- *
ADSORPTION (Chemistry) , *CHEMICAL stability , *CHEMICAL properties , *MALACHITE green , *ADSORPTION kinetics , *ADSORPTION isotherms - Abstract
To enhance the physical and chemical properties and stability of magnetic MOFs, and to improve their adsorption and reuse performance, an innovative modification strategy involving hybridization with three-dimensional (3D) terminal carboxyl hyperbranched polymers was employed. A novel polymer composite material, Fe3O4@MOF/HBPC, was synthesized and its morphological characteristics were analyzed. The adsorption properties of Fe3O4@MOF/HBPC were tested by removing Malachite Green (MG) from aqueous solutions. Various influencing factors, including dosage, pH, and temperature, as well as adsorption kinetics, isotherms, and thermodynamics were investigated. The results showed that the stretching vibration peaks of Fe3O4@MOF/HBPC appeared at 1708 cm−1, 1408 cm−1, 1278 cm−1, 1112 cm−1, and 543 cm−1, corresponding to the C=O, –COO−, O–H, C–O, and Fe–O bands, respectively. Fe3O4@MOF/HBPC exhibited a negative charge and a spherical structure. The composite material contained the elements O, C, Fe, and N, and the assembly process had a minimal impact on the crystal structure. For MG removal, the optimal reaction conditions were a dosage of 20 mg and pH 6. The adsorption process followed a pseudo-first-order kinetic model and a Langmuir isotherm model, and it was found to be endothermic and spontaneous, involving both physical and chemical adsorption. Regarding recycling and reuse, Fe3O4@MOF/HBPC demonstrated a recycling efficiency of over 90.8%, with a removing efficiency of MG of above 87.5% after three cycles, indicating excellent stability and reusability. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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28. Variations of chemical, physical, mechanical properties, and biological and antimicrobial effectiveness of Ti alloys by coating with CaP doped with different amounts of Zn via micro-arc oxidation (MAO) technique.
- Author
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Buyuksungur, Senem, Parau, Anca Constantina, Dinu, Mihaela, Pana, Iulian, Vitelaru, Catalin, Schmidt, Jürgen, Tanir, Tuğba Endoğan, Hasirci, Vasif, Vladescu (Dragomir), Alina, and Hasirci, Nesrin
- Subjects
- *
ESCHERICHIA coli , *CHEMICAL properties , *ELECTROLYTE solutions , *PHOSPHATE coating , *SURFACE coatings - Abstract
Titanium alloys are preferred metals as implant materials due to their advantageous combination of low density and high biocompatibility. However, the augmentation of implant surfaces with calcium-based coatings becomes essential to regulate corrosion rates and enhance the osteoconductive properties of the implant material. In this study, titanium alloys, specifically Ti6Al4V, underwent a transformative process wherein they were coated with calcium phosphate (CaP) ceramics doped with zinc (Zn) via micro-arc oxidation (MAO) technique, using varying concentrations of Zn compound in the electrolyte solutions. The chemical and physical properties of the freshly prepared samples were analyzed, both initially and after culturing them with Saos-2 cells. Furthermore, the antimicrobial efficacy against E. coli was examined. The findings unveiled the remarkable efficiency of the MAO technique in forming an uniformly distributed coat on Ti6Al4V, thereby enhancing its mechanical resilience and biocompatibility, depending upon the preparation parameters employed. It was shown that Zn doped calcium coating is very efficient to regulate various parameters such as corrosion rate and mechanical strength, and an increase in Zn content exhibited a favorable impact on cell attachment and antimicrobial efficacy. Surface modification of metallic implants via MAO technique can be applied in the production of advanced implant materials. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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29. Effects of Zn2+ substitution on the dielectric properties, chemical bonding properties, and crystal structure of Mg3(PO4)2 ceramics.
- Author
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Wang, DongFeng, Liu, Xinwei, Ge, Kaiyuan, Zou, Yule, Wang, Zijun, Feng, Zhanbai, Duan, Guangbin, Du, Jialun, and Wu, Haitao
- Subjects
- *
DIELECTRIC loss , *PERMITTIVITY , *MICROWAVE spectroscopy , *CHEMICAL properties , *RIETVELD refinement , *DIELECTRIC properties - Abstract
A series of (Mg 1- x Zn x) 3 (PO 4) 2 (x = 0.02–0.10) microwave dielectric ceramics were fabricated by the solid-state reaction method and investigated in terms of crystal structure, chemical bond properties, and dielectric properties were analyzed. The XRD data indicates that (Mg 1- x Zn x) 3 (PO 4) 2 samples belong to the monoclinic crystal with P 2 1 /c space group and no detectable secondary phases. The Rietveld refinement was employed to obtain crystal parameters. In addition, the results of chemical bond properties reveal that the lattice energy and ionicity of Mg (2)–O (3) bonds play a primary effect on the dielectric loss and dielectric constant, respectively. The bond energy of Mg(l)-O (2) bonds plays a dominant role in thermal stability. The far-infrared spectroscopy was employed to explore the intrinsic dielectric parameters, and the results showed that peaks below 400 cm-l contributed 78.9 % to ε′ and 99.1 % to ε″. The Raman data demonstrated that the Raman shift and FWHM exhibit an important influence on Q × f. The optimal performance was achieved in (Mg 0.94 Zn 0.06) 3 (PO 4) 2 ceramics: ε r = 5.00, Q × f = 84,674 GHz, τ f = −59.98 ppm/°C. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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30. Nitrogen‐Induced Microcrystalline‐to‐Nanocrystalline Structure Transition in Diamond Films Grown by Microwave Plasma Chemical Vapor Deposition: Comparison of N2 and NH3 Precursors.
- Author
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Martyanov, Artem, Tiazhelov, Ivan, Voronov, Valery, Savin, Sergey, Popovich, Alexey, Ralchenko, Victor, and Sedov, Vadim
- Subjects
- *
DIAMOND thin films , *CHEMICAL vapor deposition , *DIAMOND films , *MICROWAVE plasmas , *CHEMICAL properties , *NITROGEN plasmas , *ELECTRON field emission - Abstract
The structure and properties of polycrystalline chemical vapor deposition (CVD) diamond coatings grown by microwave plasma CVD in H2–CH4 mixtures can be effectively controlled by nitrogen admixture in the process gas. Here, a comparative study of adding nitrogen from different precursors, N2 and ammonia NH3, in concentrations up to 0.4%vol on grain size, texture, surface roughness, and sp2/sp3 ratio of the produced films on Si substrates is performed. A transition from microcrystalline to smooth nanocrystalline diamond structure is found to occur at a certain concentration of the precursor, for NH3 this threshold concentration being much lower, 0.02–0.1%, than for N2. The higher activity of ammonia is associated with easier formation of cyano radicals in the plasma as detected with optical emission spectroscopy, in accord with the lower bond‐dissociation energy for NH3 compared to N2. On the contrary, a smaller addition (0.004%) of either N2 or NH3 promotes almost doubling of the growth rate, while preserving the microcrystalline structure of the film. The results establish ammonia as a convenient alternative precursor to commonly used N2 added in the plasma for the diamond film structure modifications. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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31. Formation and biological activities of foreign body giant cells in response to biomaterials.
- Author
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Cai, Fangyuan, Jiang, Bulin, and He, Fuming
- Subjects
FOREIGN bodies ,CLINICAL medicine ,CELLULAR signal transduction ,CHEMICAL properties ,MACROPHAGES - Abstract
The integration of biomaterials in medical applications triggers the foreign body response (FBR), a multi-stage immune reaction characterized by the formation of foreign body giant cells (FBGCs). Originating from the fusion of monocyte/macrophage lineage cells, FBGCs are pivotal participants during tissue-material interactions. This review provides an in-depth examination of the molecular processes during FBGC formation, highlighting signaling pathways and fusion mediators in response to both exogenous and endogenous stimuli. Moreover, a wide range of material-specific characteristics, such as surface chemical and physical properties, has been proven to influence the fusion of macrophages into FBGCs. Multifaceted biological activities of FBGCs are also explored, with emphasis on their phagocytic capabilities and extracellular secretory functions, which profoundly affect the vascularization, degradation, and encapsulation of the biomaterials. This review further elucidates the heterogeneity of FBGCs and their diverse roles during FBR, as demonstrated by their distinct behaviors in response to different materials. By presenting a comprehensive understanding of FBGCs, this review intends to provide strategies and insights into optimizing biocompatibility and the therapeutic potential of biomaterials for enhanced stability and efficacy in clinical applications. As a hallmark of the foreign body response (FBR), foreign body giant cells (FBGCs) significantly impact the success of implantable biomaterials, potentially leading to complications such as chronic inflammation, fibrosis, and device failure. Understanding the role of FBGCs and modulating their responses are vital for successful material applications. This review provides a comprehensive overview of the molecules and signaling pathways guiding macrophage fusion into FBGCs. By elucidating the physical and chemical properties of materials inducing distinct levels of FBGCs, potential strategies of materials in modulating FBGC formation are investigated. Additionally, the biological activities of FBGCs and their heterogeneity in responses to different material categories in vivo are highlighted in this review, offering crucial insights for improving the biocompatibility and efficacy of biomaterials. [Display omitted] [ABSTRACT FROM AUTHOR]
- Published
- 2024
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32. Layer dependence photoelectrochemical properties of p–n homojunction 2D nanomaterial and energy storage device.
- Author
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Muhabie, Adem Ali
- Subjects
OPTOELECTRONIC devices ,CHEMICAL properties ,BAND gaps ,ENERGY storage ,RAMAN spectroscopy - Abstract
Conventional doping methods are not suitable for atomically thin two-dimensional (2D) transition metal dichalcogenides (TMDCs), making it difficult to create high-quality 2D homogeneous p–n junctions. Two-dimensional tungsten diselenide (WSe2) is a promising material for energy storage in flexible electronic and optoelectronic devices due to its unique optical, photonic, electronic, and chemical properties. In this study, we present a novel, simple, and efficient method for the preparation of homogeneous p–n junctions WSe2-based optoelectronics device and the corresponding PEC properties, and we employ a straightforward effective n-type doping adsorption technique to construct a lateral 2D WSe2 p–n homojunction. We observe a peak shift and significant increase in the intensity of photoluminescence (PL), Raman spectroscopy, and UV−vis spectrophotometry for monolayer WSe2 when electron doping occurs using n-type dopants, in comparison to bulk and few-layer WSe2 flakes. We report enhanced photoelectrochemical (PEC) properties in WSe2 flakes through n-type organic dopant mediation, forming WSe2 p–n homojunction. The PEC properties were dependent on the thickness of WSe2 layers, with PEC efficiency decreasing as the number of layers increased. Single-layer WSe2 demonstrated a higher current density, larger band gap, and greater incident photo-to-current efficiency compared to few-layer WSe2. These findings provide fundamental insights and straightforward preparation methods for constructing high-quality 2D homogeneous p–n junctions for future optoelectronic devices. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
33. Manifestation of relativistic effects in the chemical properties of nihonium and moscovium revealed by gas chromatography studies.
- Author
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Yakushev, A., Khuyagbaatar, J., Dullmann, Ch. E., Block, M., Cantemir, R. A., Cox, D. M., Dietzel, D., Giacoppo, F., Hrabar, Y., Ilias, M., Jager, E., Krier, J., Krupp, D., Kurz, N., Lens, L., Lochner, S., Mokry, Ch., Mosat, P., Pershina, V., and Raeder, S.
- Subjects
- *
CHEMICAL properties , *SILICON oxide , *ATOMIC orbitals , *GAS chromatography , *SILICON surfaces - Abstract
Chemical reactivity of the superheavy elements nihonium (Nh, element 113) and moscovium (Mc, element 115) has been studied by the gas-solid chromatography method using a new combined chromatography and detection setup. The Mc isotope 288 Mc, was produced in the nuclear fusion reaction of 48Ca ions with 243Am targets at the GSI Helmholtzzentrum Darmstadt, Germany. After isolating 288Mc ions in the gas-filled separator TASCA, adsorption of 288Mc and its decay product 284Nh on silicon oxide and gold surfaces was investigated. As a result of this work, the values of the adsorption enthalpy of Nh and Mc on the silicon oxide surface were determined for the first time,(Mc) = 54+51 kJ/mol and -AHSdO2 (Nh) = 58+8 kJ/mol (68% c.i.). The obtained ^Hads values are in good agreement with results of advanced relativistic calculations. Both elements, Nh and Mc, were shown to interact more weakly with the silicon oxide surface than their lighter homologues Tl and Bi, respectively. However, Nh and Mc turned out to be more reactive than the neighbouring closed-shell and quasi-closed-shell elements copernicium (Cn, element 112) and flerovium (Fl, element 114), respectively. The established trend is explained by the influence of strong relativistic effects on the valence atomic orbitals of these elements. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
34. Green and efficient separation of vanadium and chromium from high-chromium vanadium slag: a review of recent developments.
- Author
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Liu, Weizao, Wang, Zhenghao, Cao, Wen, Liang, Yanjie, Rohani, Sohrab, Xin, Yuntao, Hua, Jinmao, Ding, Chunlian, and Lv, Xuewei
- Subjects
- *
MANUFACTURING processes , *CHROMIUM , *CHEMICAL properties , *SLAG , *MINERALS - Abstract
Vanadium(V) and chromium (Cr) are important strategic resources due to their outstanding physicochemical properties. Due to their similar physical and chemical properties, V and Cr are often associated and coexist in many minerals. This review highlights the significance of V and Cr extraction and separation from high-chromium vanadium slag, emphasizing the key separation techniques. Current strategies for vanadium–chromium separation include separation during the extraction process, that is selective extraction of one of the elements from the slag and co-extraction of vanadium and chromium into solution followed by separation of vanadium and chromium from the solution. Both strategies are pivotal for optimizing the extraction process and enhancing industrial applications. This comprehensive review provides insights into the separation methods, addressing the challenges and advancements in the field. The elucidation of the importance of vanadium and chromium, coupled with a detailed analysis of high-chromium vanadium slag and current separation techniques, contributes to the utilization of vanadium–titanium-bearing magnetite resources with a high content of chromium and also evolves the knowledge in this critical area. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
35. Polytypic metal chalcogenide nanocrystals.
- Author
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Wu, Liang, Li, Yi, Liu, Guo-Qiang, and Yu, Shu-Hong
- Subjects
- *
CRYSTAL structure , *METAL crystals , *CHEMICAL properties , *CHALCOGENIDES , *PHOTOVOLTAIC power generation - Abstract
By engineering chemically identical but structurally distinct materials into intricate and sophisticated polytypic nanostructures, which often surpass their pure phase objects and even produce novel physical and chemical properties, exciting applications in the fields of photovoltaics, electronics and photocatalysis can be achieved. In recent decades, various methods have been developed for synthesizing a library of polytypic nanocrystals encompassing IV, III–V and II–VI polytypic semiconductors. The exceptional performances of polytypic metal chalcogenide nanocrystals have been observed, making them highly promising candidates for applications in photonics and electronics. However, achieving high-precision control over the morphology, composition, crystal structure, size, homojunctions, and periodicity of polytypic metal chalcogenide nanostructures remains a significant synthetic challenge. This review article offers a comprehensive overview of recent progress in the synthesis and control of polytypic metal chalcogenide nanocrystals using colloidal synthetic strategies. Starting from a concise introduction on the crystal structures of metal chalcogenides, the subsequent discussion delves into the colloidal synthesis of polytypic metal chalcogenide nanocrystals, followed by an in-depth exploration of the key factors governing polytypic structure construction. Subsequently, we provide comprehensive insights into the physical properties of polytypic metal chalcogenide nanocrystals, which exhibit strong correlations with their applications. Thereafter, we emphasize the significance of polytypic nanostructures in various applications, such as photovoltaics, photocatalysis, transistors, thermoelectrics, stress sensors, and the electrocatalytic hydrogen evolution. Finally, we present a summary of the recent advancements in this research field and provide insightful perspectives on the forthcoming challenges, opportunities, and future research directions. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
36. Evolution of transition metal dichalcogenide film properties during chemical vapor deposition: from monolayer islands to nanowalls.
- Author
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Loginov, A B, Kuvatov, M M, Ismagilov, R R, Sapkov, I V, Fedotov, P V, Kleshch, V I, Obraztsova, E D, and Obraztsov, A N
- Subjects
- *
CHEMICAL vapor deposition , *TRANSITION metals , *METALLIC films , *CHEMICAL properties , *ELECTRICAL conductivity measurement - Abstract
Unique properties possessed by transition metal dichalcogenides (TMDs) attract much attention in terms of investigation of their formation and dependence of their characteristics on the production process parameters. Here, we investigate the formation of TMD films during chemical vapor deposition (CVD) in a mixture of thermally activated gaseous H2S and vaporized transition metals. Our observations of changes in morphology, Raman spectra, and photoluminescence (PL) properties in combination with in situ measurements of the electrical conductivity of the deposits formed at various precursor concentrations and CVD durations are evidence of existence of particular stages in the TMD material formation. Gradual transformation of PL spectra from trion to exciton type is detected for different stages of the material formation. The obtained results and proposed methods provide tailoring of TMD film characteristics necessary for particular applications like photodetectors, photocatalysts, and gas sensors. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
37. Photocatalytic furan-to-pyrrole conversion.
- Author
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Kim, Donghyeon, You, Jaehyun, Lee, Da Hye, Hong, Hojin, Kim, Dongwook, and Park, Yoonsu
- Subjects
- *
DRUG discovery , *UMPOLUNG , *CHEMICAL properties , *HETEROCYCLIC compounds , *CHARGE exchange - Abstract
The identity of a heteroatom within an aromatic ring influences the chemical properties of that heterocyclic compound. Systematically evaluating the effect of a single atom, however, poses synthetic challenges, primarily as a result of thermodynamic mismatches in atomic exchange processes. We present a photocatalytic strategy that swaps an oxygen atom of furan with a nitrogen group, directly converting the furan into a pyrrole analog in a single intermolecular reaction. High compatibility was observed with various furan derivatives and nitrogen nucleophiles commonly used in drug discovery, and the late-stage functionalization furnished otherwise difficult-to-access pyrroles from naturally occurring furans of high molecular complexity. Mechanistic analysis suggested that polarity inversion through single electron transfer initiates the redox-neutral atom exchange processes at room temperature. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
38. Cu0·1In0·01/S-1 catalysts with high efficiency towards methanol steam reforming.
- Author
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Jiao, Cheng-Yang, Wu, Qiong-Ru, Du, Ze-Yu, Wang, Ji-Lei, Xu, Hu, Chen, Qun, Xu, Yan, and Mei, Hua
- Subjects
- *
ZEOLITE catalysts , *STEAM reforming , *COPPER , *HYDROGEN as fuel , *CHEMICAL properties - Abstract
Cu 0·1 /S-1, Cu 0·1 Zn 0·01 /S-1, Cu 0.1 In x /S-1 (x = 0.01, 0.03, 0.05) and Cu 0·1 Ce 0·01 /S-1 were successfully prepared with S-1 as the carrier material and applied to methanol steam reforming (MSR) reaction. To further explore its chemical and physical properties, XRD, BET, SEM-EDS, ICP, FTIR, H 2 -TPR, NH 3 -TPD, CO 2 -TPD, and Raman were used to characterize the synthetic S-1 zeolite catalysts. The measured physicochemical properties revealed that utilizing S-1 zeolite as the carrier effectively altered the size of the metal particles, enhancing their dispersion and reduction characteristics. Compared with five different types of S-1 zeolite catalysts, the Cu 0·1 In 0·01 /S-1 catalyst has a large specific surface area and pore size. It exhibited superior active metal dispersion, with the lowest reduction temperature for the active metal CuO. The catalyst also showed a high Lewis acid content on its surface, forming the In-Lewis acid site. Consequently, the Cu 0·1 In 0·01 /S-1 catalyst exhibits exceptional performance in methanol steam reforming for hydrogen production reactions. It exhibited the best performance with a methanol conversion rate of 100%, H 2 selectivity of 100% under the conditions of 1 MPa, 250 °C, the S/C molar ratio of 2.5, and the WHSV of 0.5 h−1, which outperforms most of the reported catalysts in methanol steam reforming. © 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. [Display omitted] • Cu 0 · 1 In 0 · 01 /S- 1 catalyst was prepared by wet impregnation method and applied to MSR reaction. • The synthesis method which In was employed as a promotor significantly improved the catalytic activity during MSR. • Excellent catalytic performance was achieved with methanol conversion of 100% and H 2 selectivity of 100% at 250 °C. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
39. Thinning the Bulk into the Soft: Flexible and Stretchable Germanium Photodetectors.
- Author
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Zhao, Guopeng and Guo, Qinglei
- Subjects
FLEXIBLE electronics ,SURFACE morphology ,PHOTODETECTORS ,GERMANIUM ,CHEMICAL properties - Abstract
Inorganic semiconductor‐based nano/micro‐membranes are of great interest and can be used as active materials for high‐performance and flexible electronics, due to their unique and stable physical or chemical properties. However, the creation of high‐quality and single‐crystalline semiconducting membranes, particularly germanium (Ge) membranes, remains a significant challenge. In this study, a wet etching approach is developed to thin bulk Ge into soft Ge membranes, which are further used to fabricate flexible and stretchable photodetectors. The thickness of the obtained Ge membranes can be precisely controlled, with a minimum thickness of ≈1.6 µm. Investigations on the surface morphology, surface chemical composition, and Raman shifts indicate that the prepared Ge membranes are single‐crystalline and suitable for the following device fabrication. As an example, flexible and stretchable Ge photodetectors, of which the stretchability is realized by a meshed‐structure design, are demonstrated. Bending (with a minimum radius of 4 mm and a bending cycle of 10 000 times) and stretching (with a stretching strain of up to 10%) tests result in negligible variations in the device performance, revealing good flexibility, and stretchability, as well as the significant potentials of the prepared Ge membranes as candidates for flexible electronics. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
40. Metal-Cation-Induced Tiny Ripple on Graphene.
- Author
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Huang, Yingying, Li, Hanlin, Zhu, Liuyuan, Song, Yongshun, and Fang, Haiping
- Subjects
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DENSITY functional theory , *METAL ions , *CHEMICAL properties , *GRAPHENE , *ELASTIC modulus , *TRACE elements - Abstract
Ripples on graphene play a crucial role in manipulating its physical and chemical properties. However, producing ripples, especially at the nanoscale, remains challenging with current experimental methods. In this study, we report that tiny ripples in graphene can be generated by the adsorption of a single metal cation (Na+, K+, Mg2+, Ca2+, Cu2+, Fe3+) onto a graphene sheet, based on the density functional theory calculations. We attribute this to the cation–π interaction between the metal cation and the aromatic rings on the graphene surface, which makes the carbon atoms closer to metal ions, causing deformation of the graphene sheet, especially in the out-of-plane direction, thereby creating ripples. The equivalent pressures applied to graphene sheets in out-of-plane direction, generated by metal cation–π interactions, reach magnitudes on the order of gigapascals (GPa). More importantly, the electronic and mechanical properties of graphene sheets are modified by the adsorption of various metal cations, resulting in opened bandgaps and enhanced rigidity characterized by a higher elastic modulus. These findings show great potential for applications for producing ripples at the nanoscale in graphene through the regulation of metal cation adsorption. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
41. Synthesis and Performance Evaluation of Metallocene Polyalphaolefins (mPAO) Base Oil with Anti-Friction and Anti-Wear Properties.
- Author
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Hu, Qidi, Zeng, Kai, Han, Sheng, Xu, Jian, Hu, Wenjing, and Li, Jiusheng
- Subjects
- *
BASE oils , *METHYL triflate , *MECHANICAL wear , *CHEMICAL properties , *INFRARED spectroscopy - Abstract
Anti-wear and anti-oxidation abilities are two key properties of lubricants that play a crucial role in ensuring long-term stable equipment operation. In this study, we aimed to develop a base oil with good anti-oxidation and anti-wear properties for use under extreme pressure. The as-prepared metallocene polyalphaolefin (mPAO) was chemically modified using the trifluoromethanesulfonic acid (TfOH) catalysis through an alkylating reaction with triphenyl phosphorothioate (TPPT). During the experiments, when the reaction temperature exceeded 70 °C or the concentration of TfOH exceeded 2.67%, the β -scission reaction in the alkylation process became significantly more pronounced. The physical and chemical properties of TPPT-modified mPAO (T-mPAO) were evaluated by nuclear magnetic resonance spectroscopy, Fourier trans-form infrared spectroscopy, gel–permeation chromatography, and ASTM standards. T-mPAO showed significantly improved antioxidant capacity, with the initial oxidation temperature increasing by 32 °C compared to the base oil, and it exhibited the slowest increase in acid number in the 96-h oven oxidation test. The tribological tests showed that T-mPAO had the lowest friction coefficient, wear track, and wear rate (72.7% lower than that of mPAO) as well as the highest PB (238 kg) and PD (250 kg) among all tested samples. Compared to mPAO, the average friction coefficient of TPPT-modified mPAO in the four-ball friction test was reduced by 30.5%, and by 16.4% in the TE77 reciprocating friction test. Based on the experimental results, T-mPAO had strong anti-oxidation ability and excellent lubricating performance.The successful synthesis of multifunctional mPAO has enabled lubricant base oil additization, making it possible to use it in more demanding work scenarios, greatly broadening its application scope and making lubricant formulation blending more flexible. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
42. Optimized Drop-Casted Polyaniline Thin Films for High-Sensitivity Electrochemical and Optical pH Sensors.
- Author
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Mücke, Bruna Eduarda Darolt, Rossignatti, Beatriz Cotting, Abegão, Luis Miguel Gomes, Barbosa, Martin Schwellberger, and Mello, Hugo José Nogueira Pedroza Dias
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- *
CHEMICAL properties , *CONDUCTING polymers , *CHEMICAL detectors , *SUBSTRATES (Materials science) , *ELECTROCHEMICAL sensors - Abstract
Conducting polymers used in chemical sensors are attractive because of their ability to confer reversible properties controlled by the doping/de-doping process. Polyaniline (PANI) is one of the most prominent materials used due to its ease of synthesis, tailored properties, and higher stability. Here, PANI thin films deposited by the drop-casting method on fluorine-doped tin oxide (FTO) substrates were used in electrochemical and optical sensors for pH measurement. The response of the devices was correlated with the deposition parameters; namely, the volume of deposition solution dropped on the substrate and the concentration of the solution, which was determined by the weight ratio of polymer to solvent. The characterisation of the samples aimed to determine the structure–property relationship of the films and showed that the chemical properties, oxidation states, and protonation level are similar for all samples, as concluded from the cyclic voltammetry and UV–VIS spectroscopic analysis. The sensing performance of the PANI film is correlated with its relative physical properties, thickness, and surface roughness. The highest electrochemical sensitivity obtained was 127.3 ± 6.2 mV/pH, twice the Nernst limit—the highest pH sensitivity reported to our knowledge—from the thicker and rougher sample. The highest optical sensitivity, 0.45 ± 0.05 1/pH, was obtained from a less rough sample, which is desirable as it reduces light scattering and sample oxidation. The results presented demonstrate the importance of understanding the structure–property relationship of materials for optimised sensors and their potential applications where high-sensitivity pH measurement is required. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
43. Optimizing Surface Characteristics of Stainless Steel (SUS) for Enhanced Adhesion in Heterojunction Bilayer SUS/Polyamide 66 Composites.
- Author
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Yun, Sang-Seok, Yoon, Wanjun, and Jang, Keon-Soo
- Subjects
- *
CONTACT angle , *SURFACE preparation , *CHEMICAL properties , *LIGHTWEIGHT materials , *SURFACE roughness - Abstract
The increasing environmental concerns and stringent regulations targeting emissions and energy efficiency necessitate innovative material solutions that not only comply with these standards but also enhance performance and sustainability. This study investigates the potential of heterojunction bilayer composites comprising stainless steel (SUS) and polyamide 66 (PA66), aiming to improve fuel efficiency and reduce harmful emissions by achieving lightweight materials. Joining a polymer to SUS is challenging due to the differing physical and chemical properties of each material. To address this, various surface treatment techniques such as blasting, plasma, annealing, and etching were systematically studied to determine their effects on the microstructural, chemical, and mechanical properties of the SUS surface, thereby identifying mechanisms that improve adhesion. Chemical etching using HNO3/HCl and CuSO4/HCl increased surface roughness and mechanical properties, but these properties decreased after annealing. In contrast, K3Fe(CN)6/NaOH treatment increased the lap shear strength after annealing. Blasting increased surface roughness and toughness with increasing spray pressure and further enhanced these properties after annealing. Contact angle measurements indicated that the hydrophilicity of the SUS surface improved with surface treatment and further improved due to microstructure formation after annealing. This study demonstrates that customized surface treatments can significantly enhance the interfacial adhesion and mechanical properties of SUS/polymer heterojunction bilayer composites, and further research is recommended to explore the long-term stability and durability of these treatments under various environmental conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
44. Preparation of Mesoporous Analcime/Sodalite Composite from Natural Jordanian Kaolin.
- Author
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Esaifan, Muayad, Al Daboubi, Fayiz, and Hourani, Mohammed Khair
- Subjects
- *
X-ray powder diffraction , *SODALITE , *CHEMICAL properties , *SCANNING electron microscopy , *VOLATILE organic compounds , *ZEOLITES - Abstract
In this work, a meso-macroporous analcime/sodalite zeolite composite was produced by a hybrid synthesis process between a complex template method and hydrothermal treatment at 220 °C of naturally abundant kaolinitic-rich clay, using dodecyltrimethylammonium bromide as an organic soft template to enhance the mesoporous structure. The chemical and morphological properties of the developed zeolites composite were characterized using powder X-ray diffraction (PXRD), attenuated total Reflectance–Fourier transform infrared spectroscopy (ATR-FTIR), thermogravimetric analysis (TGA), N2 adsorption/desorption; and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) methods were used to study the morphology, chemical composition and structure of the product. Two types of zeolite particles were obtained:(1) hollow microsphere with an attached analcime icositetrahedron of 30–40 µm in size and (2) sodalite microsphere with a ball-like morphology of 3–4 µm in size. Both N2 adsorption/desorption and surface area data confirmed the high potentiality of the produced zeolite composite to act as an excellent adsorbent to remove inorganic pollutants such as Cu, Cd, Cr, Ni, Zn, and Pb ions, organic pollutants such as dyes, phenolic compounds, and surfactants from water; and their high catalytic activity, especially in the oxidation reaction of volatile organic compounds. The catalytic activity and adsorption ability of the produced analcime/sodalite composite will be tested experimentally in future work. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
45. Unlocking the Potential of Different Types of Biomass‐Derived Carbon Dots as Fluorescence Lifetime Imaging Probes.
- Author
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Rosell, María, Torregrosa‐Rivero, Verónica, Herrera‐Ochoa, Diego, Garzón‐Ruiz, Andrés, García‐Martínez, Javier, Serrano, Elena, and Martín, Cristina
- Subjects
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OPTICAL properties , *CHEMICAL precursors , *FLUORESCENCE , *CHEMICAL properties , *CHEMICAL structure - Abstract
The ongoing search for innovative and environmentally friendly luminescent materials coupled with customizable physical and chemical properties at the nanoscale positions carbon dots (CDots) as ideal candidates for photonic applications. However, even today, their rational design for specific applications remains elusive due to the unknown relationship between optical and structural properties. Therefore, this study aims to fill this gap by linking the chemical structure of the precursor and synthetic conditions to the final structural composition of the CDots and, by extension, to their optical properties. The study shows that while CDots are chemically stable, their optical properties, which are determined by the carbonaceous core and surface groups, are highly pH dependent. These properties, together with the long fluorescence lifetimes observed in living cells (>10 ns), make these biomass‐derived CDots promising probes for time‐resolved fluorescence imaging. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
46. The Unique Edge Reconstructions and Related Edgeless Properties of Mono‐ and Few‐Layered α‐Phase Puckered 2D Materials.
- Author
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Xia, Mingyue, Chang, Yuan, Yu, Zhigen, Liu, Hongsheng, Zhou, Si, Zhao, Jijun, and Gao, Junfeng
- Subjects
- *
DENSITY functional theory , *ELECTRONIC structure , *CHEMICAL properties , *PHOSPHORENE , *MICROELECTRONICS - Abstract
The edge reconstruction of two‐dimensional (2D) materials is significant for the stability, properties, and applications. Significant progress has been made in understanding the edge reconstruction of 2D materials. Herein, an overview of the latest theoretical and experimental advances on edge reconstruction of α‐phase phosphorene nanoribbon and IV–VI group binary compounds MX (M = Ge, Sn; X = S, Se), focusing on the mechanism, stability, physical, and chemical properties of the edge reconstructions is provided. The status, challenges, and contradictions in experiments and theory are addressed and the progress in edge reconstruction of α‐phase puckered 2D materials as well as the effects of edge reconstruction on physicochemical properties are systematically introduced. A novel tube‐like edge reconstruction is suggested to be universal for α‐phase puckered monolayers. While ZZ(U) edge can be another important reconstruction in bilayer. Beyond the review, the edge structures of phosphorene have odd–even layered oscillations are also proposed. The edge terminations can affect the exfoliation mechanism and electronic, transport properties. Interesting, unique U‐edge, which has been verified by experiment, exhibits nearly edgeless electronic and thermal transport, which is beneficial for ultrafast microelectronics. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
47. An Ab Initio Journey toward the Molecular‐Level Understanding and Predictability of Subnanometric Metal Clusters.
- Author
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de Lara‐Castells, María Pilar
- Subjects
- *
MOLECULAR dynamics , *DENSITY functional theory , *CHEMICAL properties , *DENSITY matrices , *CATALYTIC activity - Abstract
Current advances in synthesizing and characterizing atomically precise monodisperse metal clusters (AMCs) at the subnanometer scale have opened up new possibilities in quantum materials research. Their quantizied "molecule‐like" electronic structure showcases unique stability, and physical and chemical properties differentiate them from larger nanoparticles. When integrated into inorganic materials that interact with the environment and sunlight, AMCs serve to enhance their (photo)catalytic activity and optoelectronic properties. Their tiny size makes AMCs isolated in the gas phase amenable to atom‐scale modeling using either density functional theory (DFT) or methods at a high level of ab initio theory, even addressing nonadiabatic (e.g., Jahn–Teller) effects. Surface‐supported AMCs can be routinely modeled using DFT, enabling long real‐time molecular dynamics simulations. Their optical properties can also be addressed using time‐dependent DFT or reduced density matrix (RDM) theory. These theoretical–computational efforts aim to achieve predictability and molecular‐level understanding of the stability and properties of AMCs as function of their composition, size, and structural fluxionality in different thermodynamical conditions (temperature and pressure). In this perspective, the potential of ab initio and DFT‐based modeling is illustrated through recent studies of unsupported and surface‐supported AMCs. Future directions of research are also discussed, including applications and methodological enhancements beyond the state‐of‐the‐art. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
48. Perspective: Protocells and the Path to Minimal Life.
- Author
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Deamer, David
- Subjects
- *
CHEMICAL properties , *ORGANIC compounds , *AMINO acids , *POLYMERS , *POLYMERIZATION - Abstract
The path to minimal life involves a series of stages that can be understood in terms of incremental, stepwise additions of complexity ranging from simple solutions of organic compounds to systems of encapsulated polymers capable of capturing nutrients and energy to grow and reproduce. This brief review will describe the initial stages that lead to populations of protocells capable of undergoing selection and evolution. The stages incorporate knowledge of chemical and physical properties of organic compounds, self-assembly of membranous compartments, non-enzymatic polymerization of amino acids and nucleotides followed by encapsulation of polymers to produce protocell populations. The results are based on laboratory simulations related to cyclic hydrothermal conditions on the prebiotic Earth. The final portion of the review looks ahead to what remains to be discovered about this process in order to understand the evolutionary path to minimal life. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
49. Emerging Role of p‐Block Element in Catalyzing Electrochemical NOx Reduction to Ammonia: A Theoretical Perspective.
- Author
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Yin, Hanqing and Du, Aijun
- Subjects
- *
CHEMICAL properties , *CHEMICAL reactions , *ELECTROLYTIC reduction , *NITROGEN fixation , *POLLUTANTS , *NITROGEN oxides - Abstract
Fixing earth‐abundant nitrogen elements into essential compounds is one of the ultimate issues for mankind. Electrochemical nitrogen fixation is regarded as promising to replace the Haber‐Bosch (HB) process at current stage. However, direct fixation of N2 is found skeptical recently due to the stable chemical properties of N2 molecule. In this regard, the more reactive nitrogen oxides (NOx) species came to light as an alternative of nitrogen sources. Since NOx species is one of the most prevalent pollutants in wastewater, it is also desired that NOx reduction can transform these detrimental ingredients into value‐added products such as ammonia. Like other chemical reactions, the performance of electrochemical NOx reduction to ammonia (eNOxRA) has a strong relation with the performance of catalysts. Previously, catalyst design of eNOxRA is dominantly based on transition metals. The role of p‐block elements in eNOxRA is not fully realized until very recent years. In this perspective, the up‐to‐date advances of p‐block‐contained catalysts in eNOxRA are concluded, with the role of p‐block elements specifically classified and discussed. Several strategies are also introduced to delicately investigate the interaction between p‐block elements and NOx species. At the end, some dilemmas and potential opportunities are proposed to achieve a more comprehensive understanding toward developing high‐efficient p‐block electrocatalyst for NOxRA. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
50. Preparation and characterization of chitosan-coated noisomal doxorubicin for enhanced its medical application.
- Author
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Mohamad, Ebtesam A., Yousuf, Alzahraa Alsayed, Mohamed, Rasha H., and Mohammed, Haitham S.
- Subjects
- *
PHARMACOKINETICS , *DIFFERENTIAL scanning calorimetry , *TRANSMISSION electron microscopy , *DRUG stability , *CHEMICAL properties , *DOXORUBICIN - Abstract
This study aimed to synthesize and characterize chitosan-coated noisomal doxorubicin for the purpose of enhancing its medical application, particularly in the field of cancer treatment. Doxorubicin, a potent chemotherapeutic agent, was encapsulated within noisomes, which are lipid-based nanocarriers known for their ability to efficiently deliver drugs to target sites. Chitosan, a biocompatible and biodegradable polysaccharide, was used to coat the surface of the noisomes to improve their stability and enhance drug release properties. The synthesized chitosan-coated noisomal doxorubicin was subjected to various characterization techniques to evaluate its physicochemical properties. Transmission electron microscopy (TEM) revealed a spherical structure with a diameter of 500–550 ± 5.45 nm and zeta potential of +11 ± 0.13 mV with no aggregation or agglomeration. Chitosan-coated noisomes can loaded doxorubicin with entrapping efficacy 75.19 ± 1.45%. While scanning electron microscopy (SEM) revealed well-defined pores within a fibrous surface. It is observed that chitosan-coated niosomes loading doxorubicin have optimum roughness (22.88 ± 0.71 nm). UV spectroscopy was employed to assess the drug encapsulation efficiency and release profile. Differential scanning calorimetry (DSC) helped determine the thermal behavior, which indicated a broad endotherm peak at 52.4 °C, while X-ray diffraction (XRD) analysis provided information about the crystallinity of the formulation with an intense peak at 23.79°. Fourier-transform infrared spectroscopy (FTIR) indicated the formation of new bonds between the drug and the polymer. The findings from this study will contribute to the knowledge of the physical and chemical properties of the synthesized formulation, which is crucial for ensuring its stability, drug release kinetics, and biological activity. The enhanced chitosan-coated noisomal doxorubicin has the potential to improve the effectiveness and safety of doxorubicin in cancer treatment, offering a promising strategy for enhanced medical applications. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
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