Traditional Synthesis Research Articles

A Wide-Beam Antenna Array With Spatially Variable-Orthogonal-Polarizations (SVOP) Achieved by Polarization-Mixing

This paper introduces a novel polarization-mixing strategy to significantly widen the beamwidth of dual-linear-polarized antenna arrays without changing the array topology. Instead of using the two polarizations separately as usual, it blends the orthogonal linearly-polarized radiations to achieve wider beamwidth. The proposed method is implemented on a typical ±45°-polarized base station antenna array with its thought process and working mechanism elaborated. Much wider beamwidth is achieved compared to the traditional pattern synthesis methods based on amplitude and phase weighting or sparse arrays. The beamwidth can be controlled by simply tuning one phase shifter. Importantly, this method allows all the elements to be fully excited with the same amplitude, thus avoiding using additional amplifiers or attenuators. In the meantime, the polarization-mixing method leads to spatially-variable polarizations (SVP). To obtain polarization diversity required in cellular communication systems, two SVP arrays with the same pattern shapes are designed to have their polarizations orthogonal to each other in all directions of interest. The conditions of achieving orthogonal patterns using this method are theoretically derived and thoroughly validated in theory and in simulation. It is shown that the obtained spatially-variable-orthogonal-polarization (SVOP) arrays have a much broader beam pattern and better polarization orthogonality (PO) than that of the dual-polarized antenna element.

Inorganic/organic bilayer--modified CaS:Eu2+,Ce3+ phosphor and luminescent film laminated glass for efficient solar energy utilization

CaS:Eu2+,Ce3+ are widely used in various fields, which is due to their excellent luminescent properties. However, the traditional high-temperature solid state synthesis of CaS has the disadvantage of large particle size and easy agglomeration. Also, the CaS-based material is unstable and decomposes easily in humid air. In the present study, CaS:Eu2+, Ce3+(here denoted as CaS:EuCe) phosphors with a uniform particle size, good dispersion, and small particle size (Dv50 = 13.46 μm, abbreviated as D50) have been obtained using a novel coprecipitation-mesophase decomposition (CMD) method. In addition, the inorganic-organic bilayer modification technology has been used to form core-shell structured CaS:EuCe@CaZnOS@Si69 phosphors, which could resist acidic/basic solutions and moist air. Its surface property changed from hydrophilicity (water contact angle 37.28°) to hydrophobicity (water contact angle 112.23°). Finally, the optimized phosphor was used to prepare luminescent film laminated glass, which showed the potential for use in plant growth. The reaction process of the CaS phosphor, as prepared by the CMD method, and the mechanism of the bilayer surface modification, have here been discussed in detail. We believe that the here-developed synthesis method provides a new strategy for the preparation of high-performance chalcogenide phosphors.

Multistep Synthesis of Paracetamol in Continuous Flow

p-Aminophenol (AP) is the key intermediate of the traditional synthesis of paracetamol. The method of obtaining AP included a selective reduction reaction of the generation of N-arylhydroxylamine (AHA) using nitrobenzene (NB) as the raw material, followed by a Bamberger rearrangement reaction to transfer AHA to the target product. The generation of AHA is a key step, but due to its structural instability and the incompatibility of the two reaction systems, one-pot synthesis of paracetamol faces great challenges. Considering that using flow reactors in series may avoid the problems faced by batch reactors, the article presents the strategy to obtain paracetamol via a continuous flow technology. In particular, we focus on condition screening in total synthesis experiments, including hydrogenation, Bamberger rearrangement, and amidation in flow. The continuous three-step synthesis process used NB as a raw material to generate AHA, which entered the downstream for timely conversion, achieving in situ on-demand preparation of the unstable intermediate AHA, avoiding cumbersome processing and storage processes. Moreover, each step of the reaction system exhibits excellent compatibility, and the work-up is simple.

Construction and electrochemical properties of carbon nanotube composite Mn-MOFs materials electrode for high-performance flexible supercapacitors

Metal organic frameworks (MOFs) as electrode materials for supercapacitors have attracted extensive attention due to their porous structure. However, the poor conductivity of MOFs limits the charge transfer. In this work, Mn-MOF/carbon nanotube (CNT) composites were grown directly on carbon cloth (CC) in one step by the traditional hydrothermal synthesis of MOFs to improve the electrical conductivity of Mn-MOFs. The structural and performance tests show that CNTs, as a conductive backbone, can connect Mn-MOFs to each other, which can obviously solve the problem of poor conductivity of MOF materials. The Mn-MOFs/CNTs/CC electrodes show a larger specific capacitance and excellent cycling stability by electrochemical tests. Compared to the original Mn-MOF electrode, the surface capacitance obtained increases from 188.8 mF·cm−2 to 385.8 mF·cm−2 at a current density of 0.8 mA·cm−2 and maintains a high capacitance retention of 118% after 5000 charge/discharge cycles at a current density of 5 mA·cm−2. This work confirms that the in- situ synthesis of MOFs and CNTs has promising applications in fabric-based flexible supercapacitors.

Ni3P2W18O62-Ni3(BTC)2 composite of Ni3P2W18O62 coated on the surface of the Ni3(BTC)2 with supercapacitor and H2O2 sensing properties was prepared by simple grinding strategy

Polyoxometalate-based metal-organic frameworks (POMOFs) as energy and catalytic materials have attracted considerable attention. Hence, Ni3P2W18O62-Ni3(BTC)2 (BTC=1,3,5-benzene-tricarboxylic acid) composite was successfully synthesized by a simple grinding strategy. IR, XRD, SEM, TEM and HRTEM results show that Ni3P2W18O62 is successfully coated on the surface of the Ni3(BTC)2. The specific capacitance of Ni3P2W18O62-Ni3(BTC)2 (460 F g−1 at 1 A g−1) is higher than that of precursors and reported supercapacitors when nickel foam is used as a collector. And the stability of Ni3P2W18O62-Ni3(BTC)2 is excellent after 5000 cycles. The symmetrical supercapacitor (SSC) was assembled with the Ni3P2W18O62-Ni3(BTC)2 as the electrode material and the energy density can reach 28.6 Wh kg−1 with a power density of 600 W kg−1. Ni3P2W18O62-Ni3(BTC)2 as a H2O2 sensor not only has a wide linear range (0.5 μM to 0.25 mM) and a low detection limit (0.17 μM), but also has strong stability and anti-interference ability, and can be used to detect H2O2 in real blood serum specimens. The improved capacitance and sensing properties are mainly attributed to the increased active site and faster electron/charge migration rate of the Ni3P2W18O62-Ni3(BTC)2. This study overcomes the shortcomings of traditional synthesis methods and provides new ideas for their application in electrochemistry.

Approaching High-Performance TS-1 Zeolites in the Presence of Alkali Metal Ions via Combination of Adjusting pH Value and Modulating Crystal Size.

Lewis acid zeolites play an important role in industrially important green reactions closely related to fine chemical and biomass conversion. Titanium-doped TS-1 zeolite is a milestone Lewis acid zeolite widely used in industrially significant green oxidation processes with hydrogen peroxide as an oxidant under mild conditions. TS-1 zeolites are normally synthesized in basic conditions under hydrothermal treatment. Up to now, there has still been no success in synthesizing active TS-1 Lewis acid zeolites by using inorganic alkali, e.g., NaOH or KOH as base, which is cheaper and more stable compared to the quaternary ammonium hydroxide or organic amines used in traditional synthesis. Here, an inorganic base of NaOH was employed in synthesizing active TS-1 zeolites for the first time. The crucial factor was the control of adverse effects of sodium cations on the incorporation of active titanium cations. Higher catalytic activity was achieved by further reducing the size of the TS-1 crystal by using the seed-added strategy, which uses the catalytic activity of a commercial catalyst, the production cost being much lower than commercial TS-1 catalysts, indicating great commercial potential and the possibility of preparing other cheap Lewis acid catalysts by using inorganic alkali.

Ultrafast synthesis of novel coal-based graphene and its anticorrosion properties of epoxy/graphene nanocomposite coatings

Graphene has a wide range of applications in anti-corrosion coatings due to its excellent barrier, shielding, and mechanical properties. However, traditional graphene synthesis methods, including the production of graphene oxide (GO) using Homer's method and then its reduction in the form of reduced graphene oxide (rGO) are time-consuming, energy-consuming, and environmentally polluting, which limits their application in anti-corrosion coatings. This study leveraged the capabilities of flash Joule heating (FJH) to synthesize flash coal-based graphene (FCBG) from Taixi anthracite (TA) within 200 ms without pretreatments or chemical reagents. The FJH had the advantages of low energy consumption and being environmentally friendly. Compared with the rGO, the FCBG prepared by FJH was characterized by fewer defects, larger carbon sheets, and a turbostratic structure. Moreover, carbon steel Q235 was used as the substrate to prepare anti-corrosion coatings by mixing FCBG at different flash voltages with epoxy resin (EP). Based on this, the electrochemical performance of different coatings was compared before and after salt spray corrosion. The results demonstrated that the FCBG composite anti-corrosion coating (EP/FCBG190) prepared using EP and FCBG synthesized at 190 V in the FJH, displayed stronger corrosion resistance than the EP and rGO composite coating (EP/rGO). The FJH synthesis process provides a feasible route for improving the synthesis process of the anti-corrosion coatings and the high value-added utilization of coal.

Joint DOA-Distance Estimation Method for Radar Using a Novel Time-Domain Wideband Synthesis System

In this paper, a joint direction of arrival (DOA) and distance estimation (JDDE) method using a novel time-domain wideband synthesis signal system is proposed. In contrast to traditional time-domain synthesis methods, which transmit sub-pulses separately, a uniform linear array is used, and all stepped linear frequency modulated (SLFM) sub-pulses are transmitted simultaneously. The echo signal is mixed with each transmitted signal of the corresponding antenna and filtered to separate the single-frequency components from different targets and array elements for synthesis. Single-frequency components have different frequencies and discontinuous phases due to wave-way differences. To solve the problem that single-frequency components cannot be synthesized directly, the frequency and phase of single-frequency components need to be calibrated, including frequency conversion and phase shift, which require DOA information of the targets. Consequently, a high-precision DOA algorithm that employs phase difference fitting, along with the corresponding generic phase unwrapping algorithm, is designed for the characteristics of the arrays and signal system in this paper. After obtaining the DOA information, the wideband synthesis algorithm is applied to synthesize the single-frequency components to obtain high-resolution ranging results. The theoretical analysis and simulation results show that the method has high distance resolution and JDDE accuracy. In a multi-target environment, the number of targets is not limited by the number of antennas. In addition, unlike traditional wideband synthesis methods, the method utilizes multiple transmitting antennas to send SLFM signal pulses simultaneously rather than sequentially, which enhances the response speed of the radar.

Revisiting the Green Synthesis of Nanoparticles: Uncovering Influences of Plant Extracts as Reducing Agents for Enhanced Synthesis Efficiency and Its Biomedical Applications.

Conventional nanoparticle synthesis methods involve harsh conditions, high costs, and environmental pollution. In this context, researchers are actively searching for sustainable, eco-friendly alternatives to conventional chemical synthesis methods. This has led to the development of green synthesis procedures among which the exploration of the plant-mediated synthesis of nanoparticles experienced a great development. Especially, because plant extracts can work as reducing and stabilizing agents. This opens up new possibilities for cost-effective, environmentally-friendly nanoparticle synthesis with enhanced size uniformity and stability. Moreover, bio-inspired nanoparticles derived from plants exhibit intriguing pharmacological properties, making them highly promising for use in medical applications due to their biocompatibility and nano-dimension. This study investigates the role of specific phytochemicals, such as phenolic compounds, terpenoids, and proteins, in plant-mediated nanoparticle synthesis together with their influence on particle size, stability, and properties. Additionally, we highlight the potential applications of these bio-derived nanoparticles, particularly with regard to drug delivery, disease management, agriculture, bioremediation, and application in other industries. Extensive research on scientific databases identified green synthesis methods, specifically plant-mediated synthesis, with a focus on understanding the contributions of phytochemicals like phenolic compounds, terpenoids, and proteins. The database search covered the field's development over the past 15 years. Insights gained from this exploration highlight plant-mediated green synthesis for cost-effective nanoparticle production with significant pharmacological properties. Utilizing renewable biological resources and controlling nanoparticle characteristics through biomolecule interactions offer promising avenues for future research and applications. This review delves into the scientific intricacies of plant-mediated synthesis of nanoparticles, highlighting the advantages of this approach over the traditional chemical synthesis methods. The study showcases the immense potential of green synthesis for medical and other applications, aiming to inspire further research in this exciting area and promote a more sustainable future.

In-vitro anticancer and antibacterial activities and comparative of eco-friendly synthesized silver nanoparticles using hull of Pistacia vera and rhizome of Sambucus ebulus extracts

The biogenic method of synthesizing nanoparticles offers an effective alternative to traditional chemical synthesis systems. Additionally, the rapid development of eco-friendly techniques for producing metallic nanoparticles is driven by their extensive applications in various scientific fields. The present study investigated the production of silver nanoparticles (AgNPs) using hull of Pistacia vera (PV-AgNPs) and rhizomes of Sambucus ebulus (SE-AgNPs) extracts. The eco-friendly synthesis of Ag nanoparticles was carried out by optimizing three physicochemical parameters, including silver salt concentration, temperature, and pH. Biogenic silver nanoparticles were characterized using several analytical techniques, including FESEM, EDS, XRD, TEM and UV-Vis. The average sizes of PV-AgNPs and SE-AgNPs were determined to be 19.32 nm and 15.63 nm, respectively, using X-ray diffraction patterns. These findings were consistent with the results obtained from scanning electron microscopy. The antibacterial efficacy of AgNPs was evaluated against both Gram-negative and Gram-positive pathogens. AgNPs exhibited the highest antibacterial activity against S. aureus and E. faecalis, with a minimum inhibitory concentration (MIC) value of 12.5 µg/ml for PV-AgNPs. Additionally, for SE-AgNPs, the MIC value against S. aureus was found to be 2 µg/ml, indicating a potent antibacterial effect. Moreover, the anticancer potential of AgNPs was assessed using the MTT assay on MCF-7 (breast cancer) and AGS (human gastric carcinoma) cell lines as representative cancer cell models. The IC50 value of SE-AgNPs on MCF-7 and AGS was found to be 24.3 and 32.5 μg/ml, respectively. Hence, the present study indicates that biologically synthesized AgNPs have significant potential for exploitation in various biological applications.

Influence of bismuth oxide as a sintering aid on the densification of cold sintering of zirconia

In the past decades, Zirconia (ZrO2) has emerged as a promising technical ceramic, both as high temperature structural material and electrolyte for fuel cells, etc. The traditional synthesis of ZrO2 with spark plasma sintering (SPS) usually requires a sintering temperature as high as 1200 °C. General interest in lowering the sintering temperature to reduce energy consumption and thermal stresses has led to research on two promising routes – cold sintering via temperature-dependent chemical reactivity and sintering aids, which facilitates mass transport and improves densification. Here we combine both by developing a single-step sintering process benefitting from both water vapor through the in-situ conversion of Zr(OH)4 to ZrO2 and liquid phase Bi2O3 as a sintering aid. The resultant ZrO2 has a relative density above 80% with a sintering temperature as low as 900 °C, significantly higher than that of ZrO2 without sintering aids, which had a relative density of 54%, both sintered at 50 MPa. The dependence of porosity of sintered samples as a function of sintering pressure (range: 50 MPa–300 MPa) and temperature (range 400 °C–1200 °C) is mapped out as guidance for further material property design. A linear relationship between hardness and relative density was found, with a maximal hardness of 6.6 GPa achieved in samples with 30% porosity. In addition to sintered density, phase stabilization of tetragonal ZrO2 is enhanced at sintering temperature of 900 °C with water vapor and Bi2O3, respectively.

Efficient urea electrosynthesis from carbon dioxide and nitrate via alternating Cu–W bimetallic C–N coupling sites

Electrocatalytic urea synthesis is an emerging alternative technology to the traditional energy-intensive industrial urea synthesis protocol. Novel strategies are urgently needed to promote the electrocatalytic C–N coupling process and inhibit the side reactions. Here, we report a CuWO4 catalyst with native bimetallic sites that achieves a high urea production rate (98.5 ± 3.2 μg h−1 mg−1cat) for the co-reduction of CO2 and NO3− with a high Faradaic efficiency (70.1 ± 2.4%) at −0.2 V versus the reversible hydrogen electrode. Mechanistic studies demonstrated that the combination of stable intermediates of *NO2 and *CO increases the probability of C–N coupling and reduces the potential barrier, resulting in high Faradaic efficiency and low overpotential. This study provides a new perspective on achieving efficient urea electrosynthesis by stabilizing the key reaction intermediates, which may guide the design of other electrochemical systems for high-value C–N bond-containing chemicals.

In-situ constructing pearl necklace-shaped heterostructure: Zn2+ substituted Na3V2(PO4)3 attached on carbon nano fibers with high performance for half and full Na ion cells

Na3V2(PO4)3 (NVP) emerges as prospective cathode for sodium ion batteries. However, the poor electronic and ionic conductivity hinders its development. Traditional synthesis methods only allow ex-situ bonding between the NVP grains and carbon-based substrate, leading to unstable combination. Herein, a simultaneous modification strategy to optimize the morphological features and crystal construction of NVP system is proposed. The in-situ synthesized framework consisting of NVP and high conductive carbon nano fibers (CNFs) can efficiently elevate the electrochemical performance. A distinctive pearl necklace-shaped heterostructure is successfully constructed by electrospinning and carbon-thermal reduction routes. The necklace substrate is derived from the CNFs, possessing the unique unidimensional morphology and bridging well with each other to build a high conductive network. The Zn2+-substituted NVP grains with nano size are grown on the surface of the substrate. The shortened size provides short pathway for Na+ migration, resulting in the improved kinetic characteristics. Furthermore, the substitution of Zn2+ generates p-type doping to introduce favorable hole carriers, enhancing the ionic conductivity. The reduced band gap and migration energy barrier of Na+ for Zn2+ doped NVP is demonstrated by DFT calculations. Accordingly, the modified Zn0.07-ES-800 sample releases a high capacity of 117.5 mA h g−1 at 0.1C. It delivers a capacity of 92.3 mA h g−1 at 100C and maintains 72.7 mA h g−1 after 1000 cycles. Moreover, the Zn0.07-ES-800//Zn0.07-ES-800 full cell shows a high capacity of 94.4 mA h g−1 at 0.1C and keeps 80 mA h g−1 at 1C with a high retention of 95% after 70 cycles.

DBDMH-Promoted Methylthiolation in DMSO: A Metal-Free Protocol to Methyl Sulfur Compounds with Multifunctional Groups.

Organic thioethers play an important role in the discovery of drugs and natural products. However, the green synthesis of organic sulfide compounds remains a challenging task. The convenient and efficient synthesis of 5-alkoxy-3-halo-4-methylthio-2(5H)-furanones from DMSO is performed via the mediation of 1,3-dibromo-5,5-dimethylhydantoin (DBDMH), affording a facile route for the sulfur-functionalization of 3,4-dihalo-2(5H)-furanones under transition metal-free conditions. This new approach has demonstrated the functionalization of non-aromatic Csp2-X-type halides with unique structures containing C-X, C-O, C=O and C=C bonds. Compared with traditional synthesis methods using transition metal catalysts with ligands, this reaction has many advantages, such as the lower temperature, the shorter reaction time, the wide substrate range and good functional group tolerance. Notably, DMSO plays multiple roles, and is simultaneously used as an odorless methylthiolating reagent and safe solvent.

Metal Nanoparticles as Novel Drug Delivery Systems: A Review of Current Challenges and Opportunities

Nanotechnology's intriguing characteristics have attracted a lot of study in recent years. Nanomaterials, nanoelectronics, and nanobiotechnology are all subfields of nanotechnology that share a great deal of common ground. The possibility for metal nanoparticles (MNPs) to completely transform treatment is what has made them so remarkable. In addition to avoid antibiotic resistance and improving medication delivery, MNPs have been shown to raise the efficacy index of medicines. Additionally, MNPs have applications in in vitro and in vivo tests, improved biodegradable substance production, and nutraceuticals. Improved targeting at the necessary target location is one major benefit of using metallic nanoparticles for drug delivery systems due to their improved durability and half-life in circulation. Bio-nanotechnology is expanding into the new field of green synthesis of MNPs, which is more environmentally friendly than traditional chemical and physical synthesis techniques. Focusing on environmentally friendly approaches to the preparation, surface modification, and applications of various MNPs like silver, gold, platinum, palladium, copper, zinc oxide, metal sulfide, and nanometal organic frameworks, this review seeks to present current insights into the challenges and perspectives of MNPs in drug delivery systems.

One-Step Electrocatalytic Approach Applied to the Synthesis of β-Propiolactones from CO2 and Dienes.

β-Lactones are common substructures in a variety of natural products and drugs, and they serve as versatile synthetic intermediates in the production of valuable chemical derivatives. Traditional β-lactone synthesis relies on laborious multi-step synthetic methods that use toxic compounds, sophisticated catalysts, expensive, and/or reactive chemicals. Based on the in situ electrochemical formation of metal-based nanoclusters, this paper describes the development of a one-step, room temperature electrocatalytic method for the formation of stable β-lactone from CO2 and dienes. This one-step "electrosynthesis" method results in the formation of a new class of β-lactone with high selectivity (up to 100%) and activity (up to 80% yields with respect to the reacted diene) by regulating the applied potential and current density. This work paves the way for more sustainable and environmentally friendly reaction pathways based on the in situ formation of nanoclusters as organic electrosynthesis catalysts.

Design and implementation of a virtual teacher teaching system algorithm based on facial expression recognition in the era of big data

Abstract With the development of big data, virtual course teaching has developed rapidly. In virtual teaching, the lecturer’s position is pivotal, and the virtual teacher’s lecture mainly conveys information through intuitive facial expressions, so the effectiveness of facial synthesis is crucial. However, traditional facial expression synthesis methods suffer from local distortion and lack of subtle expressions due to driving complex topological models and delays due to large computational effort. To this end, this paper proposes a facial expression extraction method based on feature point texture mapping. First, a video face expression feature point tracking algorithm is designed. Firstly, we design a video face expression feature point tracking algorithm. We use a monocular camera to capture facial expression images, use a texture mapping algorithm to detect faces and extract face feature points, and add a time threshold processing mechanism to the relevant filtering algorithm to detect face frame tracking to realize face feature point tracking in video. Secondly, the parameters are controlled by face expression animation, including head pose and face expression parameters. The head pose is solved by the Laplace algorithm, and the head rotation matrix and translation vector are output to establish the coordinate system. Finally, the stability and real-time performance of the feature point texture mapping algorithm are verified by expression capture test and recognition effect. The results of this paper show that: in the expression capture test, the average data transmission time is about 1ms, and the total expression transmission time of each video image frame is 32ms, which is 1.23ms and 9.8ms shorter than the traditional algorithm, respectively; in the expression recognition effect test, the successful recognition rate is increased by 10.2% on average compared with the traditional algorithm; and in the application to the classroom teaching effect test, 86.6% of the students are satisfied with the virtual teacher. 86.6% of the students highly agreed with the virtual teacher teaching, and 83.3% of the students thought that the model had a positive effect on the learners’ learning, which proved the superiority, real-time, stability and practicality of the algorithm designed in this paper compared with the traditional algorithm. The research work in this paper also provides solutions to the problems of virtual course teaching.

Compound K Production: Achievements and Perspectives.

Compound K (CK) is one of the major metabolites found in mammalian blood and organs following oral administration of Panax plants. CK, also known as minor ginsenoside, can be absorbed in the systemic circulation. It has garnered significant attention in healthcare and medical products due to its pharmacological activities, such as antioxidation, anticancer, antiproliferation, antidiabetics, neuroprotection, and anti-atherogenic activities. However, CK is not found in natural ginseng plants but in traditional chemical synthesis, which uses toxic solvents and leads to environmental pollution during the harvest process. Moreover, enzymatic reactions are impractical for industrial CK production due to low yield and high costs. Although CK could be generated from major ginsenosides, most ginsenosides, including protopanaxatriol-oleanane and ocotillol-type, are not converted into CK by catalyzing β-glucosidase. Therefore, microbial cell systems have been used as a promising solution, providing a safe and efficient approach to CK production. This review provides a summary of various approaches for the production of CK, including chemical and enzymatic reactions, biotransformation by the human intestinal bacteria and endophytes as well as engineered microbes. Moreover, the approaches for CK production have been discussed to improve the productivity of target compounds.

Room Temperature Ion Beam Synthesis of Ultra-Fine Molybdenum Carbide Nanoparticles: Toward a Scalable Fabrication Route for Earth-Abundant Electrodes.

Molybdenum carbides are promising low-cost electrocatalysts for electrolyzers, fuel cells, and batteries. However, synthesis of ultrafine, phase-pure carbide nanoparticles (diameter<5nm) with large surface areas remains challenging due to uncontrollable agglomeration that occurs during traditional high temperature syntheses. This work presents a scalable, physical approach to synthesize molybdenum carbide nanoparticles at room temperature by ion implantation. By tuning the implantation conditions, various molybdenum carbide phases, stoichiometries, and nanoparticle sizes can be accessed. For instance, molybdenum ion implantation into glassy carbon at 30keV energy and to a fluence of 9×1016 atcm-2 yields a surface η-Mo3C2 with a particle diameter of (10±1)nm. Molybdenum implantation into glassy carbon at 60keV to a fluence of 6×1016 atcm-2 yields a buried layer of ultrafine γ'-MoC/η-MoC nanoparticles. Carbon ion implantation at 20keV into a molybdenum thin film produces a 40nm thick layer primarily composed of β-Mo2C. The formation of nanoparticles in each molybdenum carbide phase is explained based on the Mo-C phase diagram and Monte-Carlo simulations of ion-solid interactions invoking the thermal spike model. The approaches presented are widely applicable for synthesis of other transition metal carbide nanoparticles as well.

Review of Biological methods of AgNPs Synthesis

Recently, noble metal nanoparticle synthesis has become more advanced thanks to the growth of nanotechnology. The abundance and diversity of the biomolecules that function as capping and reducing agents in biological synthesis methods make them more advantageous than other traditional synthesis techniques in terms of cost and safety. Due to their safety and environmental friendliness, biosynthesized silver nanoparticles (AgNPs) show potential uses in a variety of disciplines. The results of reported studies on the green synthesis of Ag NPs employing various stem, fruit, and seed components have been compiled together with their effects on the morphological characteristics. This review is crucial for figuring out how to synthesize Ag NPs in a method that is regulated, less expensive, and ecologically benign.