Modification Of Method Research Articles

Modification Strategies of Hexagonal Boron Nitride Nanomaterials for Photocatalysis.

Although hexagonal boron nitride (h-BN) was initially considered a less promising photocatalyst due to its large band gap and apparent chemical inertness, its unique two-dimensional lamellar structure coupled with high stability and environmental friendliness, as the second largest van der Waals material after graphene, provides a unique platform for photocatalytic innovation. This review not only highlights the intrinsic qualities of h-BN with photocatalytic potentials, such as high stability, environmental compatibility, and tunable bandgap through various modification strategies but also provides a comprehensive overview of the recent advances in h-BN-based nanomaterials for environmental and energy applications, as well as an in-depth description of the modification methods and fundamental properties for these applications. In addition, we discuss the challenges and prospects of h-BN-based nanomaterials for future photocatalysis.

Fabrication and characterization of hydroxyapatite coatings on anodized magnesium alloys by electrochemical and chemical methods intended for biodegradable implants

The fabrication of hydroxyapatite (HAP)/MgO composite coatings on Mg alloy is crucial for enhancing the corrosion resistance and biocompatibility of biomedical implants. In this study, we aimed to investigate the effects of two different surface modification methods, i.e., electrochemical (electrodeposition, ED) and chemical (solution treatment, ST), on the phase structure, degradation properties, and biocompatibility of the composite coatings in comparison to the anodized coating. The surface morphologies and crystalline structures of the coatings were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Subsequently, the degradation rate of the coatings in simulated body fluid were comprehensively evaluated by using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and scanning electrochemical microscopy (SECM) tests. Additionally, in-vitro cell proliferation assays were employed to quantitatively assess the biocompatibilities of the coatings. The results showed that both ED and ST methods were effective in depositing HAP on anodized Mg alloy, resulting in different surface morphologies with hydroxyapatite layer thicknesses of 2.71 μm and 3.56 μm, respectively. In this way, the HAP-deposited coatings exhibited improved corrosion resistances and biocompatibilities compared with those of the anodized coating. Specifically, the ST-deposited composite film displayed superior degradability and biocompatibility which was attributed to its filiform surface morphology and thicker HAP layer. Overall, the present study demonstrates the potential of HAP/MgO composite coatings for biomedical applications, with implications for the development of advanced implant materials with improved performance and biocompatibility.

Fabrication of multifunctional cotton fabrics with quaternized N-halamine endowing the synergetic rechargeable antibacterial, wound healing and self-cleaning performances

Cotton has attracted considerable attention due to its functional characteristics. The focus of research on cotton has shifted in recent years towards designing multi-functional and modified media for cotton fibers, which can be firmly combined with textiles, giving them reusability and extending their service life. This study constructed a synergistic antibacterial layer of quaternary ammonium compounds (QACs) and N-halamine (Hals) using an in-situ free radical copolymerization method in water, named QACs/Hals@cotton-Cl. The route significantly increases the number of antibacterial active centers. FTIR, XPS, and SEM were used to systematically analyze the product's chemical structure, surface morphology, and other characteristics. The modified fabric's antibacterial efficiency, wound healing, renewability, and durability were also evaluated. The chlorinated modified cotton fabric could completely eradicate S. aureus and E. coli within 10 min. Compared with pure cotton, it notably promoted the healing rate of infected wounds in mice. The modification method imparted excellent hydrophobicity to the cotton fabric, with a contact angle exceeding 130°, making it easy to remove surface stains. After 30 days of regular storage and 24 h of UV irradiation, the active chlorine concentration (Cl+%) only decreased by 25 % and 39 %, respectively, and the reduced Cl+% was effectively recharged via simple re-chlorination. The hydrophobicity and antimicrobial properties of QACs/Hals@cotton-Cl remained stable even after 20 cycles of friction. This simple synthesis technique provides a convenient approach for the scalable fabrication of multifunctional and rechargeable antibacterial textiles, with potential applications in medical devices and personal hygiene protection.

Mechanical properties and microstructure evolution of Sn–Bi-based solder joints by microalloying regulation mechanism

Sn–Bi based solders are used in electronic packaging for interconnection processes. However, the rate of research on the comprehensive performance of solders is difficult to match the rapid development of advanced manufacturing of integrated circuits, resulting in the inability to obtain interconnect structures with excellent reliability for electronic devices. To demand a more effective modification method, we chose to dope 1.0 wt % In element in Sn58Bi–1Sb alloy. The strength, micromechanical properties and creep resistance of the solder were improved due to the combined effect of solid solution strengthening and diffusely distributed second phase strengthening. Furthermore, the addition of In element dramatically improved the thermal properties and wettability due to the generation of Bi3In5 intermetallic compounds (88.9 °C) and the activation energy of the solder wettability reaction was reduced to 247.36 J/mol. Notably, the addition of In element increased the amount of β-Sn phase deviation and decreased the Schmid factor value of β-Sn phase, resulting in a significant increase in the strength and micro-zone creep resistance. Under the action of current, a large amount of uniform Bi particle deviations and sub-crystalline structures persist in the β-Sn phase of the Sn58Bi–1Sb1In solder matrix. In the Cu/Sn58Bi–1Sb1In/Cu joints, many Bi particles are staggered in the β-Sn phase. Since the resistivity of the β-Sn phase is smaller than that of the Bi phase, the energization process leads to a possible further increase of the local currents at certain locations in the β-Sn phase, which reduces the electromigration resistance of the β-Sn phase. After energization, the biphasic twin structure with excellent electromigration resistance starts to degrade. The results show that the doping of In element comprehensively improves the performance of Sn58Bi–1Sb solder. It opens up a new idea for the design of alloying modification of tin-bismuth based solder.

Medical Implant Heavy Metal Contents and Effect on Patients

Abstract Advanced metal implants are used in modern medical practice and significantly improve clinical prognosis and quality of life; however, the potential health risks caused by the release of heavy metal ions make further research in this area relevant. The aim of this study is to analyze current scientific sources on the impact of heavy metals released from metal biomedical implants on patients’ health, focusing on the clinical manifestations of these complications, the structure and characteristics of different metal implants, and the possibilities of modifying them. The following scientific methods were used in the study: analysis and synthesis, the method of analogy, induction, abstraction, and the bibliographic method. The study revealed significant health risks of heavy metal ions, such as allergic reactions, toxic complications, carcinogenesis, and systemic effects, including neurological and cardiovascular problems. Innovative modification methods, including surface treatments, nanotechnology, and the development of bio-soluble materials, showed potential to reduce these risks. However, the long-term effects of these modifications remain poorly understood and require further investigation. Heavy metal ions from biomedical implants pose significant health risks. Effective management and reduction of these risks require continuous monitoring, development of new materials, and advanced modification techniques. Further research is essential to understand the long-term effects of metal implants and to develop strategies to ensure patient safety and improve implant efficacy.

Effect of ph on Emulsifying Activity of Protein Isolates from Two Varieties (DAS and BS) of Nigerian Cultivated Solojo Cowpea (Vigna Unguiculata L. Walp)

The increasing world population has led to shortage in protein supply which necessitated the quest for new protein sources, particularly from legume. Legumes, naturally do not possess suitable functionality for application in food industry. To improve functionality, different methods of modification (physical, chemical, enzymatic) have been utilized by researchers though with some limitations. However, the use of germination has not been fully explored especially for underutilized Solojo cowpea. Therefore, the aim of this study was to evaluate the potential of germination in improving the nutritional and functional properties of flours and proteins isolated from Solojo cowpea and the corresponding effect of pH on its Emulsifying Activity as well as the stability of the isolates. The protein isolates were obtained as whole cowpea flour (WCF), full fat dark ash solojo (FFDAS) and defatted dark ash solojo (DFDAS) flours from dehalled defatted cowpea flour (DDCF) by isoelectric (CPIA) and micellization (CPIB) precipitation were studied. The emulsifying activity as well as stability were affected by pH as shown in Figures [1-12]. All the flours of DAS and BS showed lowest EA between pH 4 – pH 6. The EA decreased as the H+ increased up to the IEP increased with pH to the alkaline region. The DAS isolates had its minimum EA at pH 2- pH 4, while the BS isolate had its minimum EA at pH 2 for all treatment except 6h and 36h, which both had their minimum EA at pH 8. The value ranged between 43.34% and 50.00%; 44.44% and 51.52%; 43.28% and 49.37%; 43.99% and 49.34%; 43.80% and 52.55%; 44.81 and 60.18% for FFDAS, DFDAS, FFBS, DFBS, DAS and BS respectively. ES followed an arrangement comparable to the EA. The lowest ES was reported at pH 4 for most of the flour samples, except for, FFDAS Raw at pH 8 and DFDAS Raw at pH 6. The protein isolates of DAS and BS also had most of the ES minimum at pH 4, except DAS 72h and BS Raw with minimum at pH 2; DAS 36 h, 48 h, BS 6 h and 36 h had their minimum at pH 6; only DAS Raw had minimum ES at pH 8. The ES values ranged between 43.33% and 51.65%; 44.44% and 51.52%; 44.80% and 50.01%; 43.52% and 50.21%. 80.72% and 110.70% 80.66% and 108.82%, for FFDAS, DFDAS, FFBS, DFBS, DAS and BS respectively. There was no marked difference between the ES of the two varieties.

Metallic biomaterials in biopharmaceuticals and biomedical applications

Metallic biomaterials have captured a lot of interest because of their distinct mechanical characteristics, biocompatibility, and usefulness in biopharmaceutical and biomedical applications. These materials are essential for the creation of several medical equipment and treatment strategies. They include titanium, cobalt-chromium alloys, stainless steel, and biodegradable metals. Metallic implants in orthopaedics offer strong support for bone mending and joint replacement; they have outstanding load-bearing capacity and are resistant to corrosion and wear. Metallic heart valves and stents provide structural integrity and functionality in cardiovascular applications, enhancing patient outcomes in heart valve and coronary artery illness. Metallic biomaterials are manufactured systems created to give biological tissues intrinsic support, and they are commonly employed in stents, dental implants, orthopaedic fixations, and joint replacements. Increased implant-related issues are linked to higher biomaterial utilization because of weak implant integration, infections, mechanical instability, necrosis, and inflammation, as well as ensuring extended patient care, discomfort, and functional loss. The performance and integration of metallic biomaterials inside biological systems have been improved by developments in surface modification techniques, such as coating with biocompatible polymers and drug-eluting technology. Researchers are exploring the possibility of using biodegradable metals that eventually dissolve within the body reducing the risk of long-term issues and repeat procedures. Metallic nanoparticles have also demonstrated potential in increasing therapeutic efficacy, minimizing systemic adverse effects, and selectively targeting disease locations when included in drug delivery systems. The main metallic biomaterials will be briefly discussed in this review, along with the most important established and new methods for modification, which are used to enhance the durability, flexibility, biointegration, and of the biometals, and boost their suitability for 3D printing.

The nutritional aspects and food applications of Artocarpus altilis starch: A review

Artocarpus altilis is commonly referred to as breadfruit as it is similar to freshly baked bread. It is native to Malaysia, Southern Pacific, and the Caribbean and a mature breadfruit tree can yield between 400 and 2400 kg of breadfruit annually.​The amount of different minerals found in breadfruit varies greatly depending on the cultivar and growth area. These minerals include copper, magnesium, phosphorus, potassium, calcium, cobalt, iron, and manganese. It is abundant in calcium, vital minerals, and carbohydrates. It offers infection protection and is beneficial to heart health. It contains fatty acids that are omega 3 and 6. It is increasingly used as a food additive, regulating stability, texture, and sweetness. It is gluten-free, used in bakery products, and has anti-inflammatory, anti-malarial, and atherosclerotic properties. It is also used in value-added products like Murukku, noodles, and alcohol and is also used as bioplastics and coating materials. Therefore, drying and milling breadfruit into starch is one possible solution. In modern studies, some researcher uses many different methods to preserve or alter the properties of starch and flour via modification methods such as gamma-irradiation. This method is also called the cold-sterilization method and is non-toxic by nature that’s why most of the researchers prefer that method to increase the shelf-life of the flour/starch.

Engineering of the Phytase YiAPPA to Improve Thermostability and Activity and Its Application Potential in Dephytinization of Food Ingredients.

The aim of this study was to modify phytase YiAPPA via protein surficial residue mutation to obtain phytase mutants with improved thermostability and activity, enhancing its application potential in the food industry. First, homology modeling of YiAPPA was performed. By adopting the strategy of protein surficial residue mutation, the lysine (Lys) and glycine (Gly) residues on the protein surface were selected for site-directed mutagenesis to construct single-site mutants. Thermostability screening was performed to obtain mutants (K189R and K216R) with significantly elevated thermostability. The combined mutant K189R/K216R was constructed via beneficial mutation site stacking and characterized. Compared with those of YiAPPA, the half-life of K189R/K216R at 80°C was extended from 14.81 min to 23.35 min, half-inactivation temperature (T50 30) was increased from 55.12°C to 62.44°C, and Tm value was increased from 48.36°C to 53.18°C. Meanwhile, the specific activity of K189R/K216R at 37°C and pH 4.5 increased from 3960.81 to 4469.13 U/mg. Molecular structure modeling analysis and molecular dynamics simulation showed that new hydrogen bonds were introduced into K189R/K216R, improving the stability of certain structural units of the phytase and its thermostability. The enhanced activity was primarily attributed to reduced enzyme-substrate binding energy and shorter nucleophilic attack distance between the catalytic residue His28 and the phytate substrate. Additionally, the K189R/K216R mutant increased the hydrolysis efficiency of phytate in food ingredients by 1.73-2.36 times. This study established an effective method for the molecular modification of phytase thermostability and activity, providing the food industry with an efficient phytase for hydrolyzing phytate in food ingredients.

Methanol Steam Reforming for Hydrogen Production over Ni-Based Catalysts: State-Of-The-Art Review and Future Prospects.

With increasing global emphasis on environmental sustainability, the reliance on traditional energy sources such as coal, natural gas, and oil are encountering significant challenges. H2, known for its high energy content and pollution-free usage, emerges as a promising alternative. However, despite the great potential of H2, approximately 95 % of hydrogen production still depends on non-renewable resources. Hence, the shift towards producing H2 from renewable sources, particularly through methods like steam reforming of methanol - a renewable resource - represents a beacon of hope for advancing sustainable energy practices. This review comprehensively examines recent advancements in efficient H2 production using Ni-based catalysts in methanol steam reforming (MSR) and proposes the future prospects. Firstly, the fundamental principles of MSR technology and the significance in clean energy generation are elucidated. Subsequently, the design, synthesis techniques, and optimization strategies for enhancing the catalytic performance of Ni-based catalysts are discussed. Through the analysis of various catalyst compositions, structural adjustments, surface active sites, and modification methods, the review uncovers effective approaches for boosting the activity and durability of MSR reactions. Moreover, the review investigates the causes of deactivation in Ni-based catalysts during MSR reactions and proposes strategies for extending catalyst lifespan through fine design and optimization of operation parameters. Lastly, this review outlines the current research challenges and anticipates the future trends and potential applications of Ni-based catalysts in MSR hydrogen production. By offering a comprehensive critical analysis, this review serves as a valuable reference to enhance MSR hydrogen production efficiency and catalyst performance.

Numerical investigation on post–fire resistance of cold–formed Q960 ultra high strength steel channel section stub columns

Numerical analyses on the residual resistant performance of cold–formed Q960 ultra high strength steel (UHSS) channel section stub columns after fire exposure were reported. The proposed numerical modelling method was validated by the existing experimental results of the cold–formed EN 1.4420 austenitic stainless steel, S690 high strength steel (HSS) and S960 UHSS channel section stub columns at room temperature, and the hot-rolled EN 1.4301 austenitic stainless steel channel section stub columns after exposure to fire, where the ultimate resistance, load–end shortening curve and failure mode were considered. The satisfactory comparisons demonstrate the appropriateness of the proposed numerical modelling methodology for the Q960 UHSS channel section stub columns after fire exposure. A parametric study considering different geometric dimensions and exposure temperatures was conducted, where a total of 410 numerical models were included. The geometric dimensions of cold–formed Q960 UHSS channel section stub columns changed the effects of exposure temperature on the load–end shortening curve. For the conditions after exposure temperature less than 600 °C, the slenderness limit of Class 3 in European code could be used for cold–formed Q960 UHSS channel section stub columns. When the exposure temperatures were at 700, 800 and 900 °C, the slenderness limit of Class 3 became unsuitable. The accuracy of design approaches in EN 1993–1-12, AISI S100, AS/NZS 4600 and direct strength method (DSM) was assessed. When the exposure temperatures were at 800 and 900 °C, there were noticeable differences between the numerical results and results obtained from the abovementioned design approaches. The modification methods considering effects of exposure temperature and geometric dimensions were proposed for the EN 1993–1-12 design approach to predict ultimate resistance of the cold–formed Q960 UHSS channel section stub columns after different exposure temperatures.

A first-principles study of the lithium storage properties of transition metal doped TM-Ti2CO2 (TM=Sc, V, Cr, Mn, Fe, Co, Ni and Cu)

Two-dimensional transition metal carbides, known as MXenes, have garnered significant interest for their potential applications in lithium-ion batteries anode materials, owing to their distinctive properties. Doping, a prevalent method for material modification, involves the substitution of metal atoms within MXenes with other elements to modulate material properties. Given that MXenes inherently contain transition metals, doping with additional transition metals presents an optimal approach for enhancing their performance. In this study, we investigated the effect of doping eight transition metals (Sc, V, Cr, Mn, Fe, Co, Ni, Cu) onto Ti2CO2, aiming to elucidate their impact on the lithium storage properties of the material. Our findings reveal that the introduction of different dopant atoms induces changes in the d-band center of the material, consequently influencing the adsorption energy of lithium ions on the MXene surface in a nearly linear fashion. What’s more, doping with Sc, Cr, and Mn atoms results in an elevation of the migration energy, while doping with Fe, Co, Ni, and Cu atoms leads to a notable increase in the open circuit voltage (OCV). Remarkably, only V atom doping demonstrates an optimal combination of suitable adsorption energy, OCV (0.66 V), and minimal diffusion energy (0.11 eV). These results underscore the significance of transition metal doping in tailoring the lithium storage properties of MXene-based anode materials, offering insights for the design and optimization of next-generation lithium-ion batteries.

Single‐step preparation of intrinsic solid–solid phase change materials with excellent anti‐leakage and form‐stable performance

AbstractPhase change materials (PCM) often encounter severe problems of leakage and shape collapse concerns. Chemical modification methods, utilizing chemical bonds to bind phase change molecular chains, have the potential to address the above‐mentioned problems radically. However, this approach often entails the use of expensive raw materials and complex processes. Therefore, a simple one‐pot preparation method had been reported using earth‐abundant and inexpensive octadecyl methacrylate (OMA) and 1,6‐hexanediol diacrylate (HD) as raw materials to prepare PCM with a molecular structure of cross‐linked polymer main chains and phase change side chains through free radical polymerization. Owing to the three‐dimensional polymer main chain structure, it exhibited excellent leakage‐proof performance, maintaining its form‐stable nature at 70°C with no obvious leakage observed during the phase change process, confirming it to be an excellent intrinsic solid–solid PCM (SSPCM). Additionally, the introduction of the cross linking segment significantly improves its thermal stability, and the 50% degradation temperature increased significantly from 228.8 to 355.9°C. Moreover, the latent heat increased with the decrease of the crosslinking density until the molar ratio of HD/OMA was reduced to 1/40 and then tended to reach constant. At the optimal ratio the latent heat of SSPCM can reach 88.23 J g−1. Excessive crosslinking density will affect the stacking tightness of molecular chains during the crystallization process, thereby reducing the latent heat.

Activated Carbon from Coconut Shells as a Modifier of Urea–Formaldehyde Resin in Particleboard Production

Various methods for the effective modification of urea–formaldehyde (UF) adhesives, aimed at enhancing the performance of wood-based materials, have been continually explored worldwide. The aim of this work was to investigate and evaluate the effect of introducing small amounts (0.25–1.5%) of activated carbon from coconut shells (ACCS) in UF adhesive on the properties of particleboard. The performed investigations of the adhesive mixture’s properties showed an increase in both viscosity and reactivity. Moreover, the use of loadings of 0.75% and 1% had a positive effect on mechanical properties such as bending strength, modulus of elasticity, and internal bond. In these variants, a delay in the degradation of the adhesive bonds by water was also observed, as indicated by the lower thickness swelling values measured after 2 h. However, under long-term exposure to water, the modification had no considerable effect on the dimensional stability of the boards. Markedly, the addition of 1 and 1.5% of ACCS resulted in a reduction in formaldehyde content, which can be attributed to the excellent adsorption capacity of activated carbon. Overall, a loading of 1% was found to be optimal, resulting in improved strength, enhanced water resistance, and reduced formaldehyde content.

High Energy Electron Beam as an Effective Method for Molecular Modification and Thermoelectric Enhancement of PEDOT:PSS

High Energy Electron Beam as an Effective Method for Molecular Modification and Thermoelectric Enhancement of PEDOT:PSS

An investigation of a strengthening polysaccharide interfacial membrane strategy utilizing an anionic polysaccharide-alkaline ligand interfacial assembly for all-liquid printing

The applications of polysaccharides as emulsifiers are limited due to the lack of hydrophobicity. However, traditional hydrophobic modification methods used for polysaccharides are complicated and involve significant mechanical and thermal losses. In this study, soy hull polysaccharide (SHP) and terminally aminopropylated polydimethylsiloxane (NPN) were selected to investigate the feasibility of a simple and green interfacial membrane strengthening strategy based on the interfacial polymerization of anionic polysaccharides and fat-soluble alkaline ligands. Our results show that deprotonated SHP and protonated NPN can be complexed at the water/oil (W/O) interface, reduce interfacial tension, and form a strong membrane structure. Moreover, they can quickly form a membrane at the W/O interface upon the moment of contact to produce stable all-liquid printing products with complex patterns. However, the molecular weight of NPN affects the complexation reaction. Consequently, this study has long-term implications to expanding the areas of application for anionic polysaccharides.

Experimental Investigation on the Interfacial Characteristics of Tight Oil Rocks Induced by Tuning Brine Chemistry.

Currently, research on enhancing imbibition oil recovery in tight oil reservoirs through the ion-tuning technique remains limited. Two critical parameters for capillary imbibition are the wettability and interfacial tension between oil and water. In this investigation, we manipulate the properties of two types of formation water for both aged and unaged samples by diluting brine and altering ion composition. Subsequently, we employ captive and pendant-drop methods to assess rock wettability and interfacial tension under varied brine conditions. Additionally, we elucidate the primary mechanisms underlying changes in rock wettability and interfacial tension. Meanwhile, we analyze capillarity characteristics and assess the relative significance of wettability and interfacial tension. Results indicate that there is a critical interfacial tension with progressive dilution of two types of formation water. However, modifying ion composition leads to a complex trend in interfacial tension, which can be explained qualitatively through the Gibbs adsorption isotherm. For unaged samples, the contact angle demonstrates a pronounced water-wet characteristic, showing a nonmonotonic trend with respect to dilution times. Remarkably, the rock surface exhibits the strongest water-wet, particularly evident in the case of FW-10, largely influenced by variations in interfacial tension. Conversely, aged samples demonstrate strong oil-wet, with a critical salinity resulting in the lowest contact angle, while altering brine ion types can alter rock wettability from strongly oil-wet to intermediate-wet, which is not sufficient to result in the wettability alteration. The removal of multivalent cations is proposed as the most effective method for wettability modification. Furthermore, capillarity variations among different brine cases are primarily contingent upon contact angle changes, and interfacial tension does not have a significant change when regulating the brine properties. Consequently, we emphasize the significance of wettability in the adoption of ion-tuned brine techniques for tight oil reservoirs. Overall, our study underscores the potential of reasonably regulating brine properties to enhance capillarity and, thereby, improve imbibition oil recovery.

Using the methodology of transformation of geophysical fields in the study of dike-type ore systems in the zone of influence of the Chai-Yurinsky deep fault

Identification of prospecting geophysical signs of promising areas at the level of ore nodes and fields, deposits and ore structures (ore-localizing structures) has always been one of the main contents of geophysical research. However, especially at the deposit – ore structures level, very often the solution of these tasks becomes very difficult and difficult to implement. The problem is that, in general, rocks in the research area are quite contrasting in their physical properties; however, ore-bearing dike bodies represented by beresitized diorite-porphyrites do not always confidently differ in their physical characteristics from the sandy, carbonaceous, sulfidized and shale sedimentary rocks that contain them. The use of approaches based on statistical processing techniques in the interpretation of geophysical data made it possible to establish geological and geophysical signs of gold-quartz mineralization of the dike type within the study area and thus predict gold mineralization.The paper presents the results of processing geophysical materials in order to create a list of features characteristic of gold-quartz deposits of the dyke type in the Central-Kolyma region (Magadan Oblast).The geophysical research complex consisted of electrical profiling and magnetic exploration. MMPOS-2 magnetometers were used to measure the geomagnetic field. The coordinates of the measurement points were determined using a GPS receiver structurally connected to a magnetometer. The methodology of the work provided for the introduction of variations of the geomagnetic field. The variation of the Earth’s magnetic field was taken into account using the SURV software. The work by the electrical profiling method was carried out using an instrument complex: AIE-2 using the median gradient method in modification of induced polarization (SG-VP) at a frequency of 0.3 Hz. Supply line AB=800-900 m, receiving line MN=10 m.The presented set of works is capable of solving the problems of forecasting gold mineralization in the zone of influence of the Chai-Yurinsky fault of the Yana-Kolyma metallogenic system. Based on the interpretation of the geophysical data, prospecting geological and geophysical signs of gold-quartz mineralization within the ore field are outlined.One of the promising methodological methods of interpretation in determining the search signs of potentially ore zones is electrical exploration by the method of induced polarization.

Achieving High-Performance Na3V2(PO4)2F3 Cathode Material through a Bifunctional N-Doped Carbon Network.

Na3V2(PO4)2F3 (NVPF) is emerging as a popular cathode for sodium-ion batteries owing to its stable structure, high operating voltage, and large energy density. However, its practical application is hindered by its low conductivity. In addition, due to the loss of fluorine during synthesis, Na3V2(PO4)3 (NVP) impurity is often easily generated, resulting in a decrease in actual operating voltage. Herein, a bifunctional carbon network composed of an N-doped carbon layer and carbon bridge is constructed around NVPF particles. Through pyrolysis of polydopamine (PDA), the NVPF particles are covered in situ by an N-doped carbon layer, and the carbon bridge generated by polytetrafluoroethylene (PTFE) is also coated with N-doped carbon. Besides, PTFE also serves as a fluorine supplement to ensure that pure NVPF is obtained. As a result, the bifunctional N-doped carbon network-modified NVPF delivers a high reversible capacity (125.7 mA h g-1 at 0.2 C) and appreciable cycle stability (92.7% at 1 C over 300 cycles, and 89.8% at 10 C over 1500 cycles). When assembled into a full cell with a commercial hard carbon anode, it displays a discharge median voltage of up to 3.62 V at 0.2 C. Furthermore, it achieves a high energy density of 373.7 W h kg-1 at a power density of 461.2 W kg-1, with an excellent specific energy retention of 78.2% after 200 cycles. Therefore, this modification method is expected to be extended to other fluorine-containing materials with poor electrical conductivity.

A statistical method for protocol modifications with heterogeneous population variances

During the course of a clinical trial, the procedure may need to be modified based on medical or practical results. For example, in trials with low recruitment rates, the data monitoring committee often changes the inclusion/exclusion criteria, the number of sites, the endpoint, or the protocol itself. When such changes occur, protocol amendments are needed. However, the actual patient population after protocol amendments may be slightly different from the target population. In this study, we focus on the scenario in which the populations have heterogeneous variances across the modifications of trial procedures due to protocol amendments. A statistical method based on the Satterthwaite approximation with corresponding sample size adjustments is developed to evaluate the treatment effect. Our simulation demonstrates that the proposed method controls the type I error rate and provides sufficient power.