Silicon Compounds Research Articles

Advances in the application of silicon-based materials in anodes for lithium-ion batteries

Lithium-ion batteries (LIBs) are a vital energy storage technology being utilized increasingly in electric cars, portable electronics, energy storage systems, and other industries as the world focuses more on clean energy and sustainable development. Notwithstanding, the constraints associated with conventional graphite anode materials concerning energy density and cycle stability provide a challenge in fulfilling the forthcoming demand for high-performance batteries. Because silicon compounds offer a substantially greater theoretical specific capacity than conventional graphite anodes, they have gained popularity as research targets for anode materials for next-generation high-performance lithium-ion batteries. However, silicon materials still face many challenges in commercial applications. It has a low first-time coulombic efficiency, which increases the cost of the battery and reduces its actual usable capacity. Its solid electrolyte interface (SEI) film formed during charging and discharging is less stable, which can easily lead to battery performance degradation. To overcome the challenges of silicon materials in LIBs cell applications, this paper summarises the application of silicon nanostructures, silicon/carbon composites, and silicon/metal composites in LIBs. It aims to broaden its application in LIBs further.

The Use of Diatomite-Based Composites for the Immobilization of Toxic Heavy Metals in Industrial Wastes Using Post-Flotation Sediment as an Example.

Composite materials based on diatomite (DT) with the addition of biochar (BC), dolomite (DL), and bentonite (BN) were developed. The effect of chemical modification on the chemical structure of the resulting composites was investigated, and their influence on heavy metal immobilization and the ecotoxicity of post-flotation sediments was evaluated. It was demonstrated that the chemical modifications resulted in notable alterations to the chemical properties of the composites compared to pure DT and mixtures of DT with BC, DL, and BN. An increase in negative charge was observed in all variants. The addition of BC introduced valuable chemically and thermally resistant organic components into the composite. Among the chemical modifications, composites with the addition of perlite exhibited the lowest values of negative surface charge, which was attributed to the dissolution and transformation of silicon compounds and traces of kaolinite during their initial etching with sodium hydroxide. The materials exhibited varying efficiencies in metal immobilization, which is determined by both the type of DT additive and the type of chemical modification applied. The greatest efficacy in reducing the mobility of heavy metals was observed in the PFS with the addition of DT and BC without modification and with the addition of DT and BC after the modification of H2SO4 and H2O2: Cd 8% and 6%; Cr 71% and 69%; Cu 12% and 14%; Ni 10% and Zn 15%; and 4% and 5%. In addition, for Zn and Pb, good efficacy in reducing the content of mobile forms of these elements was observed for DT and DL without appropriate modification: 4% and 20%. The highest reduction in ecotoxicity was observed in the PFS with the addition of DT and BC, followed by BN and DL, which demonstrated comparable efficacy to materials with DT and BN.

Fusible glass-crystalline binder in the spodumene–manganese cordierite system

Low-melting glass-crystalline materials with a low temperature coefficient of linear expansion (TCLE) are widely used in various engineering fields. These materials are utilized for joints, protective coatings, additives in sintering of ceramic materials, including as matrices for high-strength dispersion-reinforced materials based on oxygen-free silicon compounds. This paper presents the results of a study on glass-crystalline materials in the pseudo-binary spodumene–manganese cordierite system. Based on experimental data, a fusibility diagram was constructed. Crystalline phases formed during the cooling of the glass melts were identified using X-ray phase analysis and their crystallization tendency was evaluated. It was found that the crystallization ability of the glasses decreases with an increasing content of manganese cordierite. The most promising, low-melting glass composition was identified, with a LiAlSi2O6:Mg2Al4Si5O18 ratio of 30:70 wt.%. The glass formation temperature for this compostion lies in the range of 1200–12500C, and the practical melting temperature is 14500C. The synthesized glass exhibits softening and intensive crystallization onset temperatures of 7600C and 9600C, respectively. The TCLE of the glass is 34.910–7 0С–1. The primary crystalline phase, -spodumene, forms bundles of needle-like crystals 10–15 m in length within the residual glass phase, reducing the material’s TCLE to 20.910–7 0С–1. The developed material shows potential as a glass-crystalline binder for producing high-strength ceramic materials (wear-resistant and impact-resistant) based on SiC and Si3N4 with reduced sintering temperatures.

Synthesis, Characterization and Photoluminescence Studies of near-UV excitable green-emitting NaBaScSi2O7: Eu2+ phosphor with high Internal Quantum Efficiency and Remarkable Thermal Stability

Green-emitting phosphor NaBaScSi2O7:Eu2+ was synthesized by “Amorphous Metal Complex” method using water soluble silicon compound. Eu2+ doped NaBaScSi2O7 exhibited a broad green emission band centered between 500 and 510 nm. The high luminescence intensity of the as-synthesized phosphors may owe to the synthesis procedure based on Amorphous Metal Complex (AMC) method which helps in the homogeneous distribution of Eu2+ ions in the matrix as well as the double annealing in graphite and H2/N2 reducing atmosphere. Upon excitation at 365 nm, the composition-optimized NaBaScSi2O7:Eu2+ exhibited strong green light peaking at 501 nm with the CIE chromaticity (0.146, 0.375) and a high internal quantum efficiency of about 77%. The thermally stable luminescence properties were also studied. The results indicate NaBaScSi2O7:Eu2+ as an attractive candidate for use as a conversion phosphor for Phosphor Converted White light-emitting diode (pc-WLEDs) applications.

Modeling of Phosphate Sorption Process on the Surface of Rockfos® Material Using Langmuir Isotherms

In this study, we aimed to develop a mathematical description of the process of phosphate sorption on RockfosÒ material using the Langmuir isotherm and determine the basic parameters for modeling this process. The RockfosÒ material was formed through the thermal treatment of opoka at 980 °C and is highly reactive due to its significant calcium and silicon compound content. This study included an evaluation of the phosphate retention efficiency on the material as a function of the phosphate concentration in the initial solution (0.5 mg/L, 1.0 mg/L, and 2.0 mg/L), sorbent grain size (1.0–1.6 mm, 1.6–2.5 mm, and 2.0–5.0 mm), and process temperature (5 °C, 10 °C, 15 °C, 20 °C, and 25 °C). It was found that an increase in the process temperature and the phosphate concentration in the solution favored sorption, while the effect of the sorbent grain size was ambiguous. It was determined that sorption can be described well using the Langmuir linearization of the Langmuir model. Thermodynamic analysis and the separation coefficient suggest that phosphorus sorption on Rockfos® material is primarily based on chemisorption, and the process is endothermic and spontaneous over the entire temperature range. The determined parameters of the tested material, especially the qmax (maximum sorption capacity), provide a basis for the design of a filter for removing phosphate from wastewater, assuming that the load is equal to the inflow to the filter and adheres to the specified requirements for treated wastewater.

Two-Dimensional Siloxene: A Promising Silicon-Based Material with Buffered Volume Change As Anode for Lithium Ion Batteries

Silicon has emerged as a potential anode material for lithium-ion batteries due to its high theoretical capacity of 3579 mAh g−1 (Li3.75Si). However, the alloy reaction with a high lithium content presents challenges, such as significant volumetric expansion and an unstable solid electrolyte interphase layer, which are detrimental to the electrodes and lead to rapid capacity fade [1]. Siloxene, a silicon compound with a layered structure, has attracted attention in lithium-ion battery applications due to its small volume change and moderate capacity [2, 3]. This material is obtained through the topotactic deintercalation of Ca2+ from layered CaSi2 [4]. Microscopically, the layered structure of siloxene consists of Si6 rings interconnected with or without oxygen to form planes, with Si–OH/Si–H bonds on the surface of these planes [5]. Macroscopically, siloxene exhibits a morphology of stacked layered sheets. Our research explored how the layered morphology of siloxene changes during the lithiation/delithiation process. Figure 1 showed that the siloxene sheets bulge together during lithiation and revert to separate sheets after delithiation. The buffered volume change of the layered siloxene material contributed to significantly better cycling performance compared to chunky SiO and spherical Si/C materials. Additionally, the cycling performance of siloxene was further improved when it was blended with graphite materials.[1] Kim, N., Kim, Y., Sung, J., & Cho, J. (2023). Issues impeding the commercialization of laboratory innovations for energy-dense Si-containing lithium-ion batteries. Nature Energy, 8(9), 921-933.[2] Loaiza, L. C., Monconduit, L., & Seznec, V. (2020). Si and Ge‐based anode materials for Li‐, Na‐, and K‐ion batteries: a perspective from structure to electrochemical mechanism. Small, 16(5), 1905260.[3] Loaiza, L. C., Dupré, N., Davoisne, C., Madec, L., Monconduit, L., & Seznec, V. (2021). Complex lithiation mechanism of siloxene and germanane: two promising battery electrode materials. Journal of The Electrochemical Society, 168(1), 010510.[4] Yamanaka, S., Matsuura, H., & Ishikawa, M. (1996). New deintercalation reaction of calcium from calcium disilicide. Synthesis of layered polysilane. Materials Research Bulletin, 31(3), 307-316.[5] Weiss, A., Beil, G. & Meyer, H. (1980). The Topochemical Reaction of CaSi2 to a Two-Dimensional Subsiliceous Acid Si6H3(OH)3 (= Kautskys’ Siloxene). Zeitschrift für Naturforschung B, 35(1), 25-30. Figure 1

Cutting-Edge Developments in Metal Halide Perovskites Core/Shell Heterocrystals: from Photodetectors to Biomedical Applications.

In recent years, the performance of metal halide perovskite (MHP)-based detectors (photon, biomedical, and X-ray detection) has significantly improved, resulting in higher carrier mobilities, longer carrier diffusion lengths, and excellent absorption coefficients. However, the widespread adoption of halide perovskites has been hindered by issues related to their stability and toxicity. Various strategies have been adopted to address these challenges, focusing on enhancing ambient stability and reducing toxicity by encapsulating MHPs within stable and robust host materials, such as silicon compounds, metal oxides, chalcogenides, and lead-free perovskites. This review focuses on recent developments in hybrid nanostructure-based detectors (photon, biomedical, and X-ray), particularly core/shell architectures, and provides a comprehensive analysis of techniques for mitigating degradation due to light and oxygen exposure, UV irradiance, and thermal effects. This review enhances the understanding of current advancements in core/shell-based detectors.

Recovery of Titanium from Red Mud Using Carbothermic Reduction and High Pressure Leaching of the Slag in an Autoclave

Red mud is a by-product of alumina production, which is largely stored in landfills that can endanger the environment. Red mud, or bauxite residue, is a mixture of inorganic compounds of iron, aluminum, sodium, titanium, calcium and silicon mostly, as well as a large number of rare earth elements in small quantities. Although certain methods of using red mud already exist, none of them have been widely implemented on a large scale. This paper proposes a combination of two methods for the utilization of red mud, first by carbothermic reduction and then, by leaching under high pressure in an autoclave in order to extract useful components from it with a focus on titanium. In the first part of the work, the red mud was reduced with carbon at 1600 °C in an electric arc furnace, with the aim of removing as much iron as possible using magnetic separation. After separation, the slag is leached in an autoclave at different parameters in order to obtain the highest possible yield of titanium, aiming for the formation of titanium oxysulfate and avoiding silica gel formation. A maximal leaching efficiency of titanium of 95% was reached at 150 °C using 5 mol/L sulfuric acid with 9 bar oxygen in 2 h. We found that high-pressure conditions enabled avoiding the formation of silica gel during leaching of the slag using 5 mol/L sulfuric acid, which is a big problem at atmospheric pressure. Previously silica gel formation was prevented using the dry digestion process with 12 mol/L sulfuric acid under atmospheric pressure.

Glass-ceramic binder of cordierite composition for low-temperature sintering of high-strength ceramic materials based on oxygen-free silicon compounds

The mechanical properties of composite ceramic materials obtained based on oxygen-free silicon compounds are largely determined by the properties of the glass binder. This paper presents the results of studies aimed at determining the most fusible glass in the pseudo-binary system 2MgO2Al2O35SiO2–2MnO2Al2O35SiO2 with a high tendency to crystallize as a glass-ceramic binder for low-temperature sintering of high-strength ceramic materials based on oxygen-free silicon compounds. The crystallization tendency of the experimental melts decreases with an increase in in the content of manganese cordierite, as confirmed by X-ray and infrared spectroscopic studies. Based on experimental studies, a melting diagram was constructed, which was used to determine the ratio between magnesium cordierite and manganese cordierite (50:50 wt.%), ensuring a minimum melt temperature of 12750C. The melting point of the glass of the specified composition is 14500C. The synthesized glass is characterized by a softening point of 8000C and crystallizes intensively at 10300C. The The thermal coefficient of linear expansion of the crystallized glass samples is 20.810–7 0C–1. X-ray diffraction and electron microscopic studies have shown that the developed glass is almost completely crystallized during heat treatment for 2 hours, forming a cordierite solid solution 2(Mg,Mn)O2Al2O35SiO2. The size of the cordierite phase crystals ranges from 0.5 to 3.0 m. Due to its fusibility and high crystallization tendency, the developed glass, can be proposed as a promising glass-ceramic binder for the production of high-strength ceramic materials (wear and impact resistant) based on SiC and Si3N4 with reduced sintering temperatures.

A Crystalline Mesoionic Diazasilole Featuring Low-Valent Silicon.

A 1,4,2-diazasilole containing a low-valent silicon atom has been synthesized employing a bulky imino N-heterocyclic carbene ligand. This molecular structure is characterized by a mesoionic C2N2Si five-membered ring, notable for its delocalized π electrons, intrinsic charge-separated zwitterionic properties, and a distinctly nucleophilic silicon center, culminating in 6π aromaticity. This compound manifests either mesoionic silylene or silylone characteristics upon coordination with transition metals. Demonstrating extraordinary versatility, this compound engages in diverse reactions such as coordination with iron or iridium, oxidation by S8, intramolecular ring saturation under the coordination influence of iridium, silicon atom transfer facilitated by Ph2Se2, ring contraction induced by Ph2Te2, and skeletal rearrangement triggered by Et3N•HCl. These reactions culminate in the formation of a variety of unprecedented silicon-based heterocycles, which are typically formidable to achieve using conventional methods. This study unveils previously unexplored facets of low-valent 1,4,2-diazasilole, positioning it as a promising foundational building block for future innovations in unique silicon compounds.

A Crystalline Mesoionic Diazasilole Featuring Low‐Valent Silicon

A 1,4,2‐diazasilole containing a low‐valent silicon atom has been synthesized employing a bulky imino N‐heterocyclic carbene ligand. This molecular structure is characterized by a mesoionic C2N2Si five‐membered ring, notable for its delocalized π electrons, intrinsic charge‐separated zwitterionic properties, and a distinctly nucleophilic silicon center, culminating in 6π aromaticity. This compound manifests either mesoionic silylene or silylone characteristics upon coordination with transition metals. Demonstrating extraordinary versatility, this compound engages in diverse reactions such as coordination with iron or iridium, oxidation by S8, intramolecular ring saturation under the coordination influence of iridium, silicon atom transfer facilitated by Ph2Se2, ring contraction induced by Ph2Te2, and skeletal rearrangement triggered by Et3N•HCl. These reactions culminate in the formation of a variety of unprecedented silicon‐based heterocycles, which are typically formidable to achieve using conventional methods. This study unveils previously unexplored facets of low‐valent 1,4,2‐diazasilole, positioning it as a promising foundational building block for future innovations in unique silicon compounds.

Upcycling of steel slag to activate persulfate for the degradation of chlortetracycline hydrochloride: Performance and mechanism

ABSTRACT Steel slag has great potential as an Fe-based heterogeneous Fenton-like catalyst because of its high iron content and low cost. However, the iron compounds are often encapsulated by calcium or silicon compounds in the steel slag. Herein, steel slag powder was acid-modified with salicylic acid to remove some Ca–Si compounds and thus expose more iron active sites. The results showed that the calcium content significantly decreased from 36.33 to 20.54% after modification, and more transition metals of Fe and Mn with catalytic activities were exposed simultaneously. During the activation of peroxysulphate, the conversion of Fe(Ⅱ) to Fe(Ⅲ) occurs and large amounts of •OH and 1O2 are produced as the main reactive oxygen species. The removal rates of CTC and TOC are 93.42 and 46.05%, respectively, and a degradation process may also be inhibited by CO32−, H2PO4−, and humic acid (HA). The degradation pathways of CTC mainly include both dechlorination and demethylation. In addition, salicylic acid-modified steel slag shows good repeated usability, and its removal ability is maintained at higher than 80% after four times of recycling. This study provides a new idea for designing an efficient and cheap catalyst to treat organic wastewater.

Quantum Chemical Model Calculations of Adhesion and Dissociation between Epoxy Resin and Si-Containing Molecules.

There is no doubt that when solid surfaces are modified, the functional groups and atoms directly bonded to solid atoms play a major role in adsorption interactions with molecules or resins. In this study, the adhesion and dissociation between epoxy resin and molecules containing Si atoms were analyzed. The analysis, conducted in contact with the solid surface of silicon, utilized quantum chemical calculations based on a molecular model. We compared some Si-containing molecular models to test quantum chemical calculations that contribute to the study of adhesion and dissociation between epoxy resins and solid surfaces somehow other than simple potential energy curve calculations. The AFIR (artificial force induced reaction) method, implemented in the GRRM (global reaction route mapping) program, was employed to separate an epoxy resin model molecule and three types of silicon compounds (Si(CH3)2(OH)2, Si(CH3)4, and (CH3)2SiF2) in three directions, determining their minimum dissociation energy when changing the applied energy by 2.5 kJ/mol. In systems with weak hydrogen bonds, such as Si(CH3)4 or (CH3)2SiF2, the energy required for dissociation was not large; however, in systems with strong hydrogen bonds, such as Si(CH3)2(OH)2, dissociation was more difficult in the vertical direction. Although anisotropy due to hydroxyl groups was calculated in the horizontal direction, dissociation remained relatively easy.

Design and Architecture Definition for Advanced 3D Fan-Out Wafer-Level Packaging

Advanced 2.5D/3D wafer-level fan-out packaging technologies have been studied widely in literature and industry in recent years. Miniaturization, reduction in manufacturing costs, improvement in performance, and lower power consumption using packaging technologies drive increase in interconnect density and pitch scaling. Heterogeneous systems in package used in advanced packaging often include a combination of silicon, epoxy underfill or mold compounds, and organic or inorganic passivation or redistribution layers. This heterogeneity poses challenges with manufacturability, process selection, package architecture, and test vehicle design. The coefficient of thermal expansion mismatch, wafer warpage, and wafer yield are some of the critical process challenges. Delamination of silicon side wall or passivation to epoxy underfill or mold compound, joint fatigue are critical reliability challenges. This article explores various processes and reliability challenges with 3D wafer-level fan-out packaging and provides package design and architecture guidelines to overcome these failure modes. Stacked die-to-wafer test vehicles have been used for data collection. Different assembly materials, processes, and tooling have been evaluated to define comprehensive design rules.

Investigation into the purification and regeneration of rare earth polishing powder waste via continuous solid-phase conversion

The concentration of rare earth elements (lanthanum, cerium, and praseodymium) within rare earth polishing powder waste (REPPW) typically exceeds 50 %, with the majority of impurities comprised of silicon and aluminum-related compounds. Transforming REPPW into recycled rare earth polishing powders that adhere to polishing standards in an eco-friendly and economically viable way presents a significant challenge in the industry. Traditional acid or alkaline processes predominantly recover rare earth elements as oxides, which are underutilized due to their high costs. Considering the varying forms of impurities and rare earth compounds found in REPPW, this research introduces a novel physicochemical decontamination and continuous chemical transformation process aimed at producing regenerated rare earth polishing powders. Under optimal conditions, the physicochemical two-step decontamination process achieved a rare earth recovery rate surpassing 92 %, while silicon and aluminum removal rates reached 86.12 %. During the continuous chemical transformation of REPPW, the rare earth phases in an alkaline setting followed the sequence REOF (CeO2) → RE(OH)3 → RECO3OH→RECO3F→CeLa2O3F3(CeO2), which not only facilitated phase reorganization but also enhanced the particle surface structure. Notably, these chemical transformations did not disrupt the rare earth distribution; instead, they indirectly boosted product purity and uniformly dispersed within the regenerated polishing powder particles, thereby improving polishing efficiency. Consequently, the adoption of this innovative regeneration process for polishing powders holds substantial importance for the sustainable utilization of rare earth resources.

Changes in the liver of Djungarian hamsters under conditions of a three-month supply of water-soluble silicon of various concentrations

BACKGROUND: Silicon enters the human body through drinking water, air and food. Silicon nanoparticles used in the cosmetic, pharmaceutical and food industries are known to have biological activity. Taking into account the widespread prevalence of silicon compounds, the issue of the safety of its use is becoming more urgent. AIM: To study the effect of water-soluble silicon on the morphological structure of the liver of Djungarian hamsters for three months. MATERIALS AND METHODS: The experiment was carried out on Djungarian hamsters kept in normal vivarium conditions under natural light. The animals were divided into three groups: control, which received bottled drinking water; the first experimental group, which received the same water, but with the addition of sodium metasilicate nine-hydrate at a concentration of 10 mg/l in terms of silicon; the second experimental group, which also received the same water, but with the concentration of sodium metasilicate nine-hydrate doubled (up to 20 mg/l). After three months, the animals were removed from the experiment. Sections were processed by general histological (hematoxylin and eosin, Van Gieson method, toluidine blue), histochemical (monoamine oxidase-positive cells) methods. RESULTS: In the liver of hamsters from the experimental groups, changes in the micromorphological structure were revealed, such as an increase in the nuclear area, nuclear-cytoplasmic ratio of hepatocytes, and the diameter of sinusoidal capillaries. Moreover, more pronounced changes were observed in the liver of hamsters of the second experimental group, such as polymorphic cell infiltration of the portal tracts, an increase in the number of eosinophils, deformation of hepatocyte nuclei and the appearance of apoptotic bodies. A decrease in the area of mast cells and an increase in their number, as well as the number of monoamine oxidase-positive cells in the liver of hamsters of both experimental groups were recorded. CONCLUSIONS: An increase in the concentration of silicon supplied with drinking water in both cases is reflected in the micromorphological structure of the liver of hamsters. Moreover these changes are more pronounced in the liver of hamsters of the second experimental group.

Silicon-28-Tetrafluoride as an Educt of Isotope-Engineered Silicon Compounds and Bulk Materials for Quantum Systems.

This review provides a summary of the existing literature on a crucial raw material for the production of isotopically pure semiconductors, which are essential for the development of second-generation quantum systems. Silicon-28-tetrafluoride (28SiF4) is used as an educt for several isotope-engineered chemicals, such as silane-28 (28SiH4) and silicon-28-trichloride (28SiHCl3), which are needed in the pursuit of various quantum technologies. We are exploring the entire chain from the synthesis of 28SiF4 to quantum applications. This includes the chemical properties of SiF4, isotopic enrichment, conversion to silanes, conversion to bulk 28Si and thin films, the physical properties of 28Si (spin neutrality, thermal conductivity, optical properties), and the applications in quantum computing, photonics, and quantum sensing techniques.

Synthesis of MeBICAAC Supported Si(III) Radicals and a Silylone via Reduction Route From MeBICAAC-Si(IV) Precursors.

Past one decade has witnessed a tremendous growth in the field of carbene stabilized low-valent silicon compounds unravelling very exciting properties of these molecules. Herein, we have employed a bicyclic (alkyl)(amino)carbene, (MeBICAAC) to explore the low-valent chemistry of silicon. The reduction of bicyclic (alkyl)(amino)carbene-SiCl4 complex, [(MeBICAAC)SiCl4] (1) with KC8 afforded low-valent Si complexes, including Si(III) radical [(MeBICAAC)SiCl3] (2) and a complex with silicon center in a formal zero-valent state, [(MeBICAAC)2Si] (3). Similarly, the reduction of in-situ generated MeBICAAC adduct of Me2SiCl2 with one equivalent of KC8 led to the formation of [(MeBICAAC)SiMe2Cl] (4) complex having an unpaired electron. These complexes have been characterized by IR, UV-Vis., NMR, HRMS, EPR and their solid-state structures were also elucidated by single crystal X-ray crystallography. Further, DFT calculations revealed the lower energy singlet state for complexes 1, 3 and doublet state for complexes 2, 4.

Recent progress in transition metal complexes featuring silylene as ligands.

Silylenes, divalent silicon(II) compounds, once considered highly reactive and transient species, are now widely employed as stable synthons in main-group and coordination chemistry for myriad applications. The synthesis of stable silylenes represents a major breakthrough, which led to extensive exploration of silylenes in stabilizing low-valent main-group elements and as versatile ligands in coordination chemistry and catalysis. In recent years, the exploration of transition metal complexes stabilized with silylene ligands has captivated significant research attention. This is due to their robust σ-donor characteristics and capacity to stabilize transition metals in low valent states. It has also been demonstrated that the transition metal complexes of silylenes are effective catalysts for hydroboration, hydrosilylation, hydrogenation, hydrogen isotope exchange reactions, and small molecule activation chemistry. This review article focuses on the recent progress in the synthesis and catalytic application of transition metal complexes of silylenes.

Exploring the effects of angle of incidence on stabbing resistance in advanced protective textiles: Novel experimental framework and analysis

Despite numerous research investigations to understand the influences of various structural parameters, to the authors' knowledge, no research has been the effect of different angles of incidence on stab response and performance of different types of protective textiles. Three distinct structures of 3D woven textiles and 2D plain weave fabric made with similar high-performance fiber and areal density were designed and manufactured to be tested. Two samples, one composed of a single and the other of 4-panel layers, from each fabric type structure, were prepared, and tested against stabbing at [0°], [22.5°], and [45°] angle of incidence. A new stabbing experimental setup that entertained testing of the specimens at various angles of incidence was engineered and utilized. The stabbing bench is also equipped with magnetic sensors and a UK Home Office Scientific Development Branch (HOSDB)/P1/B sharpness engineered knives to measure the impact velocity and exerted impact energy respectively. A silicon compound was utilized to imprint the Back Face Signature (BFS) on the backing material after every specimen test. Each silicon print was then scanned, digitized, and precisely measured to evaluate the stab response and performance of the specimen based on different performance variables, including Depth of Trauma (DOT), Depth of Penetration (DOP), and Length of Penetration (LOP). Besides, the post-impact surface failure modes of the fabrics were also measured using Image software and analyzed at the microscale level. The results show stab angle of incidence greatly influences the stab response and performance of protective textiles. The outcome of the study could provide not only valuable insights into understanding the stab response and capabilities of protective textiles under different angle of incidence, but also provide valuable information for protective textile manufacturer, armor developer and stab testing and standardizing organizations to consider the angle of incidence while developing, testing, optimizing, and using protective textiles in various applications.