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[Display omitted] • Interaction of the human Hb with CdS QDs of sizes 3 nm and band gap 2.88 eV has been investigated. • The life time of the heme pocket binding and reorganization of QDs were found to be 43 min & 642 min, respectively. • The maximum 71.5 % energy transfer occurred and lifetime changes from 5.45nS to1.51 ns. • The deformation and unfolding of the secondary structure of Hb have been observed. • The radius of gyration of CdS QDs-Hb increased (23 ± 0.45 nm) compare with pure Hb (11 ± 0.23 nm) and Hb becoming more unfolded. In this study, the interaction of the human hemoglobin with cost effective and chemically fabricated CdS quantum dots (QDs) (average sizes ≈3nm) has been investigated. The semiconductor QDs showed maximum visible absorption at 445 nm with excitonic formation and band gap of ≈ 2.88 eV along with hexagonal crystalline phase. The binding of QDs-Hb occurs through corona formation to the ground sate complex formation. The life time of the heme pocket binding and reorganization were found to be t 1 = 43 min and t 2 = 642 min, respectively. The emission quenching of the Hb has been indicated large energy transfer between CdS QDs and Hb with tertiary deformation of Hb. The binding thermodynamics showed highly exothermic nature. The ultrafast decay during corona formation was studied from TCSPC. The results showed that the energy transfer efficiency increases with the increase of the QDs concentration and maximum ≈71.5 % energy transfer occurs and average ultrafast lifetime varies from 5.45 ns to1.51 ns. The deformation and unfolding of the secondary structure of Hb with changes of the α-helix (≈74 % to ≈51.07 %) and β-sheets (≈8.63 % to ≈10.25 %) have been observed from circular dichroism spectrum. The SAXS spectrum showed that the radius of gyration of CdS QDs-Hb bioconjugate increased (up to 23 ± 0.45 nm) with the increase of the concentration of QDs compare with pure Hb (11 ± 0.23 nm) and Hb becoming more unfolded. [ABSTRACT FROM AUTHOR]

The enhancement of the magnetostriction for Fe-Ga alloys can significantly improve the magneto-mechanical conversion efficiency of magnetostrictive devices, which are widely applied in high-end equipment, aerospace and other fields. Recent studies have demonstrated that doping trace rare earth elements into Fe-Ga alloys can significantly enhance their magnetostriction. In this work, the < 100 >-oriented polycrystalline (Fe 81 Ga 19) 99.8 Tb 0.1 (NbC) 0.1 alloy with excellent magnetostriction was developed by employing a synergistic strategy of trace NbC-doping and quenching treatment. The < 001 >-oriented Fe-Ga alloys along the growth direction were prepared by directional solidification. The addition of NbC increased the solid solubility of Tb in the matrix of Fe-Ga alloy by 9.4 %, and this was further increased by 28.1 % after quenching treatment, inducing more L6 0 heterogeneities and enhancing lattice distortions in the matrix. The saturation magnetostriction of the < 100 > -oriented polycrystalline (Fe 81 Ga 19) 99.8 Tb 0.1 (NbC) 0.1 alloy before and after quenching reached 200 ppm and 295 ppm, respectively, which was 5.8 % and 5.6 % greater than that of the NbC-undoped (Fe 81 Ga 19) 99.9 Tb 0.1 alloy. The saturation magnetostrictions of all selected Fe-Ga alloy compositions after quenching treatment were more than 40 % higher than of the unquenched samples. The initial and average magnetostrictive strain sensitivity (dλ/dH) of all Fe-Ga alloys has been greatly improved after heating at 1200 ℃ for 2 hours. This work reveals that the reasonable alloy design and thermal treatment can effectively increase the solubility of Tb in the matrix and improve the magnetostriction of Fe-Ga alloys, which can provide a crucial guidance for future studies of magnetostrictive Fe-Ga alloys. • The Tb-doped Fe81Ga19 alloy with excellent magnetostriction was developed by the synergy strategy of trace NbC-doping and the quench treatment. • The addition of NbC and the quenching treatment increased the solid solubility of Tb by 28.1 %. • The improved solid solubility of Tb induced more L60 nanoheterogeneities and larger lattice distortion. • The 3/2λs of (Fe 81 Ga 19) 99.8 Tb 0.1 (NbC) 0.1 alloy before and after quenching measured under stress-free conditions reached 200 ppm and 295 ppm, respectively. [ABSTRACT FROM AUTHOR]

Coordination polymers (CPs) are peculiar multi-dimensional materials that find utility as luminescent sensors for ions and molecules existing in wastewater discharge. Herein, two new Cd(II)-based CPs with formula [Cd(L)(phen)]·0.5H 2 O (1) and [Cd(L)(2,2′-bipy)] (2) (H 2 L = 3,3'-((1,2-phenylenebis(methylene))bis(oxy))dibenzoic acid, phen = 1,10-phenanthroline and 2,2′-bipy = 2,2′-bipyridine) have been synthesized and characterized. The single crystal X-ray analysis for 1 reveals that Cd(II) centre adopts an octahedral geometry and is coordinated to four carboxyl O atoms from three L2− ligands and two N atoms from phen molecules. While in CP 2 , the Cd(II) centre is seven coordinated, which is completed by five carboxylate O atoms from two distinct L2− ligands and two N atoms from the 2,2-bipy ligand. Both 1 and 2 have been used as turn-off fluorescence sensor for selective and sensitive detection of Fe3+ and Cr 2 O 7 2−. The CP 1 exhibited superior selectivity and sensitivity than 2 with limit of detection (LOD) 1.732 × 10−5 M and 5.996 × 10−6 M against Fe3+ and Cr 2 O 7 2− respectively. Interestingly, the emissive behaviour of 1 get restored on adding 2-hydroxybenzoic acid (2-hyd acid) (turn on) due to the competitive formation of 2-hyd acid@Fe3+ or 2-hyd acid@Cr 2 O 7 2− and concomitant release of 1. The fluorescence recovery selectivity of 2-hyd acid over other antioxidants has been attributed to the synergistic effect of high E HOMO value and a small space steric hindrance. The sensing properties of the MOF have been addressed with the help of Hirshfeld surface and density functional theory analyses. [Display omitted] • Two new Cd(II)-based coordination polymers (CPs) were synthesized and characterized. • These CPs have been used as turn-off fluorescence sensor for selective and sensitive detection of Fe3+ and CrO 4 2−. • The emission behaviour of the CP was restored on adding 2-hydroxybenzoic acid. • The sensing properties of the MOF addressed using Hirshfeld surface and DFT analyses. [ABSTRACT FROM AUTHOR]

The photodielectric effects of rare earth elements Er, Eu, and Ho doped Na 1/2 Bi 1/2 TiO 3 (NBT) ceramics are investigated. The dependence of light intensity and irradiation time on the photodielectric effects were clarified, and the thermal-induced and photo-induced changes in permittivity are distinguished. At 1 kHz, the Δε r /ε dark (Δε r = ε photo -ε dark) of NBT-Er/Eu and NBT-Er/Ho are 2.57 % and 2.08 %, respectively. Furthermore, poling and quenching treatments are employed to improve the photodielectric effect of NBT-Er/Ho ceramics. At 1 kHz, the Δε r /ε dark of poled and quenched NBT-Er/Ho increase to 5.22 % and 2.71 %, respectively. The increase of Δε r /ε dark of poled sample is resulted from the lattice distortion of the ceramics while the increase of Δε r /ε dark of quenched sample is due to the increase in oxygen vacancies. This work is conducive to understand the unconventional optical and dielectric effects in ferroelectric ceramics. [ABSTRACT FROM AUTHOR]

[Display omitted] • A red-emitting BSA-Cu NCs probe is designed for selective and sensitive memantine detection. • Static quenching ensures precise memantine quantification using the developed probe. • The method shows excellent validation for linearity, accuracy, precision, and selectivity. • Practical utility was confirmed through pharmacokinetic monitoring of memantine in rats. This study presents a novel and sensitive analytical method for the detection of the anti-Alzheimer's drug Memantine HCl. The method utilizes the unique optical properties of red-emitting copper nanoclusters (Cu NCs) embedded in a bovine serum albumin (BSA) matrix. The copper nanoclusters were synthesized using hydrazine as a reducing agent and BSA as a stabilizer. The spectral characteristics and sensing mechanism of the developed probe were thoroughly investigated, revealing a static quenching mechanism for the interaction between Memantine HCl and the BSA-Cu NCs. Various parameters affecting the fluorescence response, including pH, reaction time, and reagent concentrations, were optimized to enhance the sensitivity and selectivity of the method. Furthermore, the method was validated according to ICH M10 guidelines, demonstrating excellent linearity over a concentration range of 25–600 ng/mL, high accuracy and precision, as well as selectivity. The applicability of the developed BSA-Cu NCs probe was evaluated for the analysis of Memantine HCl in pharmaceutical formulations and pharmacokinetics studies. The results were in good agreement with reported techniques and previous literature, highlighting the utility of the proposed method for real-world applications in the pharmaceutical and clinical fields. [ABSTRACT FROM AUTHOR]

The radiative relaxation of exciton-like formations in KCl-Na single crystal has been studied by exper-imental methods of luminescent spectroscopy. The amplifying effect of the radiation intensity with a maximum at 2.8 eV up to 500 times as compared to pure KCl has been detected in KCl-Na. The luminescence efficiency of an exciton-like formation increases with rise in: sodium ions concentration ( 10 ÷ 1000 ppm), thermal exposure ( 500◦C ÷ 600◦C ) and the degree of uniaxial deformation along and crystallographic directions. Previously, such a scale of the luminescence enhancement effect has not been registered in KCl matrix at room temperature. At high sodium concentrations (1000 ppm) in KCl-Na crystals, the additional intense emission with a maximum at 3.1 eV has also been revealed, which is typical for pair sodium ions. It is interpreted that the exciton-like formation in the sodium field with the maximum quantum yield of luminescence is formed by recombination assembly of electron-hole pairs due to the mobility of unrelaxed holes.

• The α 2 phase and the γ phase repeatedly compete to grow during heat treatment. • The α 2 phase changes into the γ phase and lamellar structure in a very short time. • The B2 phase is spheroidized during heat treatment. This study reports a new phenomenon of competitive growth between TiAl alloy structures. By annealing the β-solidified Ti-44Al-8Nb-0.1B alloy for a short time, a new phenomenon of repeated competitive growth between α 2 and γ phases is found. Finally, the (α 2 + γ) lamellar structure engulfs other structures and grows, transforming into a full lamellar structure. [ABSTRACT FROM AUTHOR]

Herein, a mild oxidation method was adopted to tailor the organic macromolecular of coal and its derivatives for preparing coal-based carbon dots. [Display omitted] • Coal-based CDs were prepared from coal and its derivatives via mild oxidation. • The particle size of coal-based CDs mainly distributes in 5–12 nm. • Coal-based CDs mainly contain sp2 microcrystalline carbon and sp3 amorphous carbon. • Coal-based CDs are rich in O/N-containing groups with favorable water solubility. • Coal-based CDs demonstrate superior selectivity and sensitivity for Cu2+ detection. Carbon dots as fluorescent probes exhibit brilliant sensitivity and selectivity in copper ion detection, which greatly depends on their microstructure. Herein, a mild oxidation method was adopted to tailor the organic macromolecules of coal and its derivatives for preparing coal-based carbon dots. Such coal-based carbon dots comprise a carbonaceous center dominated by sp2 microcrystalline carbon, surface defects formed by sp3 amorphous carbon, and oxygen/nitrogen-containing functional groups. The coal-based humic acid-based carbon dots (HA-CDs) exhibit high dispersity (∼7.6 nm), high sp2 microcrystalline carbon (61.73 %), abundant carboxyl groups (2.09 %), hydroxy groups (8.93 %), and pyridinic nitrogen (1.06 %). Due to their unique microstructure, the HA-CDs in aqueous solutions exhibit prominent fluorescence stability under different pH conditions and show superior selectivity and sensitivity to Cu2+ even in the existence of other metal ions. Within the concentration range of 0–40 µmol/L, the fluorescence intensity of HA-CDs linearly correlates with the concentration of Cu2+. The limit of detection is 0.014 µmol/L, allowing for tracing the Cu2+ concentration in flowing water. This work affords a novel idea for the microstructure design of high-sensitivity carbon dots for Cu2+ detection in the water environment. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel approach using a selective spectrofluorimetric method was used to determine Pregabalin (PG). • The method depends on the effect of varying concentrations of PG on the Eu3+-ACAC sensor's luminescence intensity, resulting in quenching. • Absorption and emission were used in the optical sensor's synthesis and characterization processes. • The method effectively determined the presence of PG in human urine, serum, and capsule samples. A novel spectrofluorimetric method with high selectivity and sensitivity was created to determine Pregabalin (PG) in pharmaceutical form, human serum, and urine. This method relies on detecting quenching in the intensity of luminescence of the europium acetylacetone complex (Eu3+-ACAC) at emission wavelength λ em = 616 nm, which results from interaction with various concentrations of PG after excitation at λ ex = 395 nm and pH 6.5 in dimethylformamide (DMF). The calibration curve was generated using concentrations ranging from 7.6 × 10-8 to 6.3 × 10-6 mol/L. The plot showed a high correlation coefficient (r2) of 0.994 with a detection limit (LOD) of 2.81 × 10-8 mol/L and a quantification limit (LOQ) of 8.5 × 10-8 mol/L. The remarkable luminescence intensity quenching of the Eu3+-ACAC by ranged concentrations of PG was effectively employed as a photo probe to determine PG in marketable form and different body fluids. Spectroscopic characterization, such as absorption and emission spectra, confirmed the obtained sensor. The improved method is verified using a range of characteristics, such as accuracy, precision, selectivity, linearity, and robustness. [ABSTRACT FROM AUTHOR]

A novel multifunctional fluorescence sensor based on zinc-based metal-organic frameworks was developed using zinc nitrate hexahydrate and pyridine-2,5-dicarboxylic acid. The fluorescence and chemical properties of fluorescence sensor has been investigated. The sensor with a excellent low detection limit was sensitive to Fe3+ and Al3+ ionic in aqueous solution. [Display omitted] Recognition and detection of Fe3+ and Al3+ ions in water are important for human health and life. Herein, a novel multifunctional fluorescence sensor based on zinc-based metal-organic frameworks (Zn-MOF) was developed using zinc nitrate hexahydrate and pyridine-2,5-dicarboxylic acid by solvothermal condition, and characterized by X-ray single crystal diffraction, elemental analysis, powder X-ray diffraction (PXRD), etc. The PXRD experiment results observed that the structure of Zn-MOF is rearranged after water molecules exchanged all 3 DMF solvates in the pores. Fluorescent sensing experiments revealed that Zn-MOF exhibits high sensitivity in detecting Fe3+ and Al3+ by significant fluorescence quenching. The limit of detection (LOD) of Fe3+ and Al3+ were 0.18 μM and 0.064 μM, respectively. The anti-interference experiment revealing that Zn-MOF has a high selectivity to detect Fe3+ and Al3+. In addition, the quenching mechanism of Zn-MOF was demonstrated to be attributed to the inner filter effect (IFE). Furthermore, in the real sample detection of tap water, the recoveries of Fe3+ and Al3+ were 103.0 %–107.9 % and 106.1 %–110.5 %, respectively, and the relative standard deviations (RSD) were less than 7.42 % and 6.20 %, respectively. This work provided an reliable method for the quantitative detection of Fe3+ and Al3+ and was successfully applied in tap water with satisfactory recovery and precision. [ABSTRACT FROM AUTHOR]

[Display omitted] • The review highlights carbon dots' potential in detecting aflatoxins. • Integration of CDs, as signal transducers, with common functional materials, such as MIP, MOF, aptamer, antibody, and metal oxides are covered. • The advantages and disadvantages of using lone carbon dots and their modified forms for detecting aflatoxins in different matrices are discussed. • The review comprehensively addresses the upcoming challenges and potential limitations of using CDs and their modified forms with future integration modes. Aflatoxins are extremely harmful and cancer-causing substances generated by specific fungi that can contaminate various agricultural products, posing serious health risks to humans, food safety, and animals. Due to their high liposolubility, aflatoxins are readily absorbed into the bloodstream through the gastrointestinal and respiratory tracts. Given their resilience and widespread occurrence, aflatoxins continue to be a global concern, necessitating continuous monitoring and the development of innovative detection methods to protect public health and ensure food security. The emergence of carbon dots (CDs) presents a promising avenue for rapidly detecting aflatoxins. CDs offer numerous advantages, including negligible cytotoxicity, water solubility, biocompatibility, chemical stability, efficient light absorption, and exceptional photoinduced electron transfer. Despite these benefits the literature contains some novel reports on using CDs for aflatoxin detection, but lacks a review article. Therefore, this review article explores novel, and emerging detection methods for aflatoxins, such as colorimetric, fluorometric, electrochemical, and electrogenerated chemiluminescence techniques, focusing on the use of modified and unmodified CDs. It also demonstrates how multi-recognition elements are combined with CDs to improve selectivity, sensitivity, and stability for aflatoxin detection. Finally, challenges and limitations for future CDs implementation in real-world assays are discussed. [ABSTRACT FROM AUTHOR]

It is challenging to decouple typical protein-like chromophoric dissolved organic matter (CDOM) fluorophores from oil-related fluorophores in natural waters using standard steady-state fluorescence techniques. In the present work, time-resolved florescence spectroscopy was explored as a means of differentiating between these two types of fluorophores. Fluorescence lifetimes of oil products were measured as a function of excitation and emission wavelength in artificial seawater. A triexponential model gave τ 1 = ~1–10 ns, τ 2 = ~3–30 ns, and τ 3 = ~0.2–2 ns. Time-resolved fluorescence amplitudes were dominated by τ 3 (τ 3 55–65 %; τ 1 25–29 %; τ 2 11–16 %) and contributions to steady-state fluorescence were dominated by τ 1 and τ 2. Lifetimes increased with decreasing λ ex. Fluorescence was quenched by halide ions, but ion concentrations in natural waters are insufficient for quenching to significantly change lifetimes. Heavier, denser oils had red-shifted emission and lower lifetimes. Results suggest that time-resolved spectroscopy can decouple oil and protein-like CDOM fluorophores at λ ex < 300 nm. [Display omitted] • Fluorescence lifetimes of oils were measured in artificial seawater. • Oil and protein-like DOM fluorophores could be decoupled using lifetimes. • Photochemical aging of oils did not significantly affect lifetimes. • Fluorescence was quenched by halide ions found in seawater. [ABSTRACT FROM AUTHOR]

In this work, the heat transfer coefficients were determined utilizing an experimental study for cooling a 15B35H boron steel, using aqueous solutions of polyalkylene glycol (PAG) as a cooling fluid. A cooling tank was designed and built to allow the fluid recirculation, where the effect of agitation and the PAG content in a concentration range of 2%–6% vol. were analyzed. The thermal histories of cylindrical probes instrumented with K-type thermocouples were obtained, and the heat transfer coefficients associated with the types of refrigeration were calculated, solving the IHCP. The results show the presence of two maximum surface heat flux denominated q1 _max for the low-temperature range and q2 _max for the high-temperature range. Getting higher q1 _max and low q2 _max is desirable to avoid distortion and cracking. It was found that 4% PAG exhibits a slight variation of heat flux values in both low and high-temperature regions, regardless of the degree of agitation, maintaining values of about 3 MW·m ^−2 for q1 _max and 5.5 MW·m ^−2 for q2 _max . In this case, q2 _max is higher than q1 _max , leading to higher cooling rates in the martensitic transformation zone, increasing the risk of distortion and cracking. In the cases of 2 y 6% PAG, agitation affects q1 _max ranging from 2.5 to 6 MW·m ^−2 , and for q2 _max from 4 to 6 MW·m ^−2 , where q1 _max is always higher than q2 _max , providing better conditions for quenching.

While the larger photosensitive area of Geiger-mode avalanche photodiodes (GmAPDs) enhances their detection range and signal collection, improving their utility in weak light detection, their practicality is limited by a long recovery time, high afterpulsing probability (AP) and excessive jitter. Utilizing a dynamic memristor as a quenching resistor, this research improves the count rate of a large-size GmAPD by 100× at an overvoltage of 2.5 V, compared with a fixed resistor-quenched GmAPD. Furthermore, at a photon pulse frequency of 1 MHz jitter time is reduced from 3.60 ns to 0.48 ns, and the afterpulsing probability is effectively mitigated from 30.88% to 8.58%.

Functionalization of nanocrystals is essential for their practical application, but synthesis on nanocrystal surfaces is limited by incompatibilities with certain key reagents. The copper-catalyzed azide-alkyne cycloaddition is among the most useful methods for ligating molecules to surfaces, but has been largely useless for semiconductor quantum dots (QDs) because Cu+ ions quickly and irreversibly quench QD fluorescence. To discover nonquenching synthetic conditions for Cu-catalyzed click reactions on QD surfaces, we developed a combinatorial fluorescence assay to screen >2000 reaction conditions to maximize cycloaddition efficiency while minimizing QD quenching. We identify conditions for complete coupling without significant quenching, which are compatible with common QD polymer surfaces and various azide/alkyne pairs. Based on insight from the combinatorial screen and mechanistic studies of Cu coordination and quenching, we find that superstoichiometric concentrations of Cu can promote full coupling if accompanied by ligands that selectively compete with the Cu from the QD surface but allow it to remain catalytically active. Applied to the conjugation of a K+ channel-specific peptidyl toxin to CdSe/ZnS QDs, we synthesize unquenched QD conjugates and image their specific and voltage-dependent affinity for K+ channels in live cells.

In the present work, the effect of quenching temperature and tempering time on the evolution of microstructure in UNS S17400 precipitation-hardening (PH) stainless steel has been investigated. Two temperatures, 950 and 1050 °C, were selected for quenching followed by tempering at 620 °C for different times ranging from 15 min to 6 h. Optical microscope (OM), electron backscattered diffraction (EBSD) and scanning electron microscope (SEM) were used to obtain the microstructural information. Energy-dispersive spectrometer (EDS) attached to SEM was used to obtain the localized chemical composition of various phases/precipitates. X-ray diffraction (XRD) was used to quantify the reverted austenite, coherently diffracting domain size and lattice strain. There was little change in the grain size with the increase in quenching temperature. On the other hand, tempering resulted in formation of precipitates of various types, which increased (as expected) with increase in tempering time. Lower quenching temperature resulted in higher reverted austenite. [ABSTRACT FROM AUTHOR]

Direct pyrolysis/KOH activation of carbon from castor shell biomass is an economical combination of two processes to breakdown biomass lignin effectively. The advanced liquid nitrogen-controlled direct pyrolysis/KOH activation technique is even a shortened process, which optimizes the fugacious bond reformation for enhancing supercapacitors' performance. Novel quenching of the red-hot activated carbon (heated at 800 °C) in liquid nitrogen is peculiar to the demonstrated structural changes. The desired throughput designated nKAC exhibited a high specific surface area of 1468 m2 g−1 over the initial 1131 m2 g−1 for KAC. In 6 M KOH electrolyte, the nKAC electrode exhibited a high specific capacitance of 481 F g−1 at 1 A g−1 and an excellent rate capability of 298 F g−1 at 30 A g−1. In symmetric two electrodes test, the electrodes of nKAC show a high energy density of 17.75 Wh kg−1 at 0.5 A g−1 in 1 M Na2SO4 electrolyte compared with 14.75 Wh kg−1 of KAC electrodes. Furthermore, the nKAC still maintained a high energy density of 12.4 Wh kg−1 at 5.0 A g−1 corresponding to a high power density of 4500 W kg−1. This simple and green method has potential applications in the synthesis of porous carbon based on waste biomass for enhancing performance of electrode materials. [ABSTRACT FROM AUTHOR]

Vanadium oxides with fast and stable Zn2+ storage are of great significance to the development of high‐performance aqueous zinc ion batteries (ZIBs), and yet they commonly suffer from structural instability and sluggish diffusion kinetics. Herein, a new "dual‐ion‐in‐sequence" intercalation strategy based on quenching is proposed to address these issues. Interestingly, it is found that the Zn2+ storage mechanism evolves from the common solid‐state ion diffusion kinetic into an intercalation pseudocapacitance as a result of the enlarged interlayer spacing of V2O5. Together with the expanded interlayer spacing arising from the "dual‐ion‐in‐sequence" intercalation, oxygen defects are simultaneously generated at the sub‐surface of the reconstructed Li@MnVO materials. Benefitting from the improved ionic diffusivity, intercalation pseudocapacitance, and fast charge transferability, full cell based on Li@MnVO cathode shows impressive rate capability and excellent cycling stability of 5000 cycles with a high energy density of 253 Wh kg‐1 at 10 A g‐1. More importantly, the capacity can maintain at 125 mAh g‐1 at 4 A g‐1 even under a raised mass loading of 10 mg cm‐2. The proposed "dual‐ion‐in‐sequence" intercalation strategy of manipulating V2O5 structure at atomic scales is a viable pathway for the high‐performance layered metal oxides, not only for ZIBs but also for other energy storage systems. [ABSTRACT FROM AUTHOR]

Adenosine triphosphate is an important biological molecule that provides energy and substrate for various cellular biochemical processes,it's ubiquitous in our lives. In this work, a novel electrochemiluminescence (ECL) sensor composed of Ru(bpy)32+, 2‐[4‐(2‐hydroxyethyl)piperazin‐1‐yl] ethanesulfonic acid (HEPES) and adenosine 5'‐triphosphate disodium salt (ATP) was developed for the first time. In this ECL system, Ru(bpy)32+ was used as the luminophore, HEPES buffer was served as the co‐reactant, and ATP was added to the system to amplify the luminous signal to investigate the ECL behavior. Through fluorescence spectroscopy, ECL spectroscopy, and cyclic voltammetry (CV), it can be hypothesized that the possible ECL mechanism is that ATP acts as an advanced co‐reaction promoter to accelerate the oxidation of HEPES to HEPES+⋅, more HEPES⋅ can be generated, which then reacts with oxidized Ru(bpy)33+ to emit stronger ECL signals. Subsequently, the influence of the ATP concentrations and the CV scanning speed was investaged. Moreover, it was observed that I− could quench the ECL intensity, the linear relationship range of I− concentration is from 10−3 to 10−6 m, the limit of detection is 3.7×10−8 m (signal/noise=3), therefore, a new, highly sensitive, and selective ECL approach for I− detection was created. [ABSTRACT FROM AUTHOR]

Water pollution due to heavy metal ions is a global issue which requires proper attention to maintain the water quality demands. Surplus amounts of copper in aqueous systems coming from industrial waste and domestic sewage could have bad influence on the surrounding ecosystem and pose a serious threat to human health. We have developed a novel, simple, cost-effective method for the detection of heavy metal ion Cu2+ using eco-friendly (3-mercaptopropyl)trimethoxysilane (MPTS) functionalized ZnS-Mn2+ quantum dots (QDs) through rapid fluorescent analysis. The QDs were synthesized, and the surface was modified with a non-toxic functionalizing agent MPTS through microwave assisted aqueous route. Such surface modified QDs were then employed as a fluorescent sensor for the detection of Cu2+ even at very low concentration. The optical properties and structural features of the QDs have been characterized by absorption spectra, fluorescence spectra, TCSPC lifetime studies, pH studies, XRD, FTIR, TEM, and zeta potential. The sensing action is based on the fluorescent quenching of MPTS capped ZnS-Mn2+ QDs which is possibly due to the effective electron transfer from QDs to Cu2+ ion. The sensing ability of the synthesized QDs was confirmed by UV-visible absorption and fluorescence spectroscopic studies. The XRD studies and FTIR spectra also confirmed the interaction of QDs with Cu2+ ions which are responsible for the sensing action. Under the optimum conditions, the Stern–Volmer plot of Cu2+ showed a good linearity within the concentration range of 0 to 4 × 10–6 M. The KSV was found to be 0.561 × 106 M–1 with the detection limit of 2.3 × 10–8 M. Selectivity studies were conducted, and the fluorescence quenching of MPTS capped ZnS-Mn2+ QDs was found to be more sensitive to Cu2+ ions even when the cationic concentrations were 100 times higher than that of Cu2+ ion. Hence, the detection of heavy metal ion Cu2+ can be performed more easily and rapidly by this fluorescent sensor, and it provides a novel green concept in the field of sensing mechanisms. [ABSTRACT FROM AUTHOR]

In this paper, a high-order compact local one-dimensional (LOD) method is proposed to solve the three-dimensional reaction-diffusion equation with nonlinear reaction term. First, the governing equation is split into three one-dimensional equations. Then, the fourth-order compact difference formulas and the Crank-Nicolson method are employed to approximate the space and time derivatives, respectively. The nonlinear reaction term is linearized by utilizing the Taylor expansions. It only needs to solve three one-dimensional tridiagonal linear systems at each time layer, which makes the computation cost-effective. After conducting theoretical analysis, we find that the truncation error of the current LOD method is of order O (τ 2 + h 4) for source spatially symmetry problems, but only of order O (τ + τ h 2) for source spatially asymmetry problems. The convergence and stability of the proposed scheme are proved by the energy analysis method. Finally, some numerical experiments are carried out to demonstrate the accuracy and the efficiency of the presented method. Furthermore, our method is also exploited in the simulation of the quenching and blow-up phenomena. [ABSTRACT FROM AUTHOR]

Aromatic amines are important chemical intermediates that hold an irreplaceable significance for synthesizing many chemical products. However, they may react with substances excreted from human bodies to generate blood poisoning, skin eczema, and dermatitis disease and even induce cancer-causing high risks to human health and the environment. Metal tungstates have been proven to be highly efficient materials for developing various toxic gases or chemical detection sensor systems. However, the major factors of the sensors, such as sensitivity, selectivity, stability, response, and recovery times, still need to be optimized for practical technological applications. In this work, Ni-doped ZnWO4 mixed metal tungstate nanocomposite material was synthesized by the hydrothermal method and explored as a sensor for the fluorometric determination of p-nitroaniline (p-NA). Transmission electron microscopy (TEM) was used for the elucidation of the optimized particle diameter. Scanning electron microscopy (SEM) was employed to observe the surface morphological changes in the material during the solid-state reactions. The vibration modes of as-prepared samples were analyzed using Fourier-transform infrared spectroscopy (FTIR). The chemical bonding and oxidation states of individual elements involved in material synthesis were observed using X-ray photoelectron spectroscopy (XPS). The PL activities of the metal tungstate nanoparticles were investigated for the sensing of p-nitroaniline (p-NA). The obtained results demonstrated that ZnNiWO4 was more effective in sensing p-NA than the other precursors were by using the quenching effect. The material showed remarkably high sensitivity towards p-NA in a concentration range of 25–1000 μM, and the limit of detection (LOD) value was found to be 1.93 × 10−8 M for ZnWO4, 2.17 × 10−8 M for NiWO4, and 2.98 × 10−8 M for ZnNiWO4, respectively. [ABSTRACT FROM AUTHOR]

Green coffee is coming into vogue as a food that contains remarkable contents of antioxidants like chlorogenic acid (ChA) and induces mild stimulation to the consumer. While most methods for determination of ChA require chromatographic separation prior its quantitation, we present the first probe and a simple, sensitive and validated luminescence method for the determination of chlorogenic acid in green and roasted coffee infusion samples that does not require a chromatographic separation. ChA can remarkably quench the luminescence intensity of the Tb3+ complex with 1-(furan-2-ylmethyl)-4-hydroxy-N-(4-methylpyridin-2-yl)-2-oxo-1,2,5,6,7,8-hexahydroquinoline-3-carboxamide (R3) in aqueous solution containing urotropine buffer at a near neutral pH 7.5 at λexc = 315 nm and λem = 545 nm. Under optimal conditions, the quenching of the luminescence intensity is directly proportional to the concentration of ChA in the range of 0.5–30 μg/mL, and the detection limit is 180 ng/mL. From measurements of luminescence decay time, it was determined that both static and dynamic quenching is induced upon coordination of ChA to Tb-R3. The related quenching constants are KS = 5.97∙104 M−1 and KD = 1.05⋅104 M−1. Finally, the method was applied successfully to the determination of ChA in real green and roasted coffee infusion samples and validated by HPLC to yield very closely matching concentrations of both methods. Therefore, this method can serve for a simple quality control of total ChA contents in coffee prior and after roasting. [ABSTRACT FROM AUTHOR]

Oxygen sensing capabilities of a series of luminescent zirconium-based porphyrinic metal–organic frameworks (MOFs) (PCN-222, PCN-223, and PCN-224) have been investigated. Design of experiments allowed identification of the most sensitive material, a PCN-224 MOF. In this material, luminescence in air is quenched by up to 7.3-fold with a bimolecular quenching constant kq of 56,000 Pa–1 s–1, which is significantly above the previously reported benchmark material of the same MOF type (kq of 34,000 Pa–1 s–1). The oxygen sensitivity increases in the order PCN-222 < PCN-223 < PCN-224 with effective Stern–Volmer (SV) constants in the range of 0.13 kPa–1 for PCN-222, 0.18 kPa–1 for PCN-223 and up to 0.45 kPa–1 for PCN-224-type materials. This effect is attributed to the increase in the porphyrin–porphyrin separation in these nanostructured materials that results in the increase in the fluorescence decay time and thus the probability of the quenching event. Defects in the nanostructure also are important and explain variations in the sensitivity within the MOFs of the same type. Among the investigated materials, those belonging to the PCN-223 type were found to be the most robust in terms of oxygen sensing capabilities with only little variation in the SV constants. The analogues of the PCN MOFs that utilize a Pt-(II) porphyrin as a building block were also prepared. It is shown that the same synthetic protocols established for the metal-free systems can be used for the metal complex. Analogous to the MOFs based on the metal-free porphyrin, the oxygen sensitivity increases from Pt-(II)-PCN-222 (KSV 30 kPa–1) via Pt-(II)-PCN-223 (KSV 40 kPa–1) to Pt-(II)-PCN-224 (KSV up to 87 kPa–1). [ABSTRACT FROM AUTHOR]

Structural, microstructural, magnetic, electrical and magneto-transport properties of La0.7Ca0.18Ba0.12Mn0.95Sn0.05O3 manganite powders, prepared by the solid state method, were investigated. Two quenching processes were performed on the samples: quenching in air and quenching to 77 K in liquid nitrogen. X-ray diffraction patterns refinement revealed that the samples crystallized in the orthorhombic structure. The scanning electron microscopy micrographs presented granular characters. The magnetization vs temperature plot showed a paramagnetic-ferromagnetic transition. The inverse susceptibility χ - 1 (T) deviation from the Curie–Weiss law revealed the existence of the phase above TC in the nitrogen-quenched sample. The hysteresis cycles reveal that the samples are ferromagnetic at 1.8 K and paramagnetic at 300 K. The resistivity curves exhibit a ferromagnetic-metallic to paramagnetic-insulating transition. The magnetoresistance increased slightly in the sample quenched to 77 K in N2. [ABSTRACT FROM AUTHOR]

The paper presents a procedure for carrying out quantitative structural-phase analysis (CSFA) based on the results of X-ray diffraction studies and measurement of specific volumes. The CSFA procedure was applied to constructing the phase composition diagrams illustrating structural changes in steels due to the exposure to an external magnetic field during quenching. The changes in the phase composition and distribution of carbon, caused by the magnetic field effect, result in an increased degree of martensite decomposition according to a two-phase mechanism, occurrence of fine carbon delamination, and formation of highly dispersed carbide phase particles, leading to the creation of a structural state, characteristic of steel after an ordinary quenching and low-temperature tempering. [ABSTRACT FROM AUTHOR]

Oil and gas production casing and compression pipes used for structures in oil and gas deposit structures contaminated with a high concentration of hydrogen sulfide should have alongside high strength and cold resistance good sulfide stress corrosion cracking resistance. Medium carbon steels alloyed with chromium and molybdenum are used extensively for such products. After quenching and tempering in the temperature range 680–720ºC these steels possess increased yield and tensile strengths along with good ductility. Alloying with molybdenum and vanadium provides a marked increase in sulfide stress corrosion cracking resistance with an increase in tempering temperature in the range indicated. [ABSTRACT FROM AUTHOR]

Processes of decomposition of metastable β-phase in quenched alloys Ti – 40% Nb – (5 – 9)% Zr during aging at 400 and 500°C are studied. The time intervals of precipitation of second phases (α and ω) are determined. The effect of 5 – 9 wt.% zirconium alloying on the variation of the structure, phase composition and properties of the alloys after quenching and aging is analyzed. The impact of additional plastic deformation by rolling after the quenching on the shift of the temperature intervals of precipitation of second phases under subsequent aging of the alloys is considered. [ABSTRACT FROM AUTHOR]

Currently, a large number of studies are being conducted in the field of application of methods of thermal and chemical-thermal treatment, and there are some unresolved technological problems. In particular, the issues of the formation of wear-resistant structures have not been sufficiently studied in the study of combined methods of chemical and thermal treatment, the development of which makes it possible to reduce the technological cycles of the hardening process of the surface layer of metals. This paper examines the issues of the formation of wear-resistant structures during technological operations that allow combining the tempering process with the saturation of the steel surface with nitrogen and carbon atoms, as well as issues of reducing the technological cycles of hardening using methods of chemical-thermal treatment, the possibility of using standard equipment, preparation of the saturation medium based on local raw materials. [ABSTRACT FROM AUTHOR]

A group of selected phenols i.e., picric acid, p-Nitrophenol, m-Nitrophenol, o-Nitrophenol, and phenol interactions were studied with a fluorescent probe carbazole in a micellar system of CTAB. CTAB concentration was optimized for maximum quenching of carbazole for each studied phenol. Interaction was studied in 0.02 and 0.1 mol/dm3 CTAB. All the studied phenols resulted in the quenching of carbazole in both CTAB concentrations though lower CTAB concentration was found optimum for highest quenching of the probe carbazole. Carbazole fluorescence quenching with phenols were explained with the help of Stern–Volmer equation that produced the constants of Stern–Volmer ( K sv ). K sv shows the sensitiveness of the method for the studied phenol and were observed in the order picric acid > phenol > m-Nitrophenol > p-Nitrophenol > o-Nitrophenol. Detection threshold (DT) and quantification threshold (QT) were observed in the order 1.76 × 10–7 – 6.30 × 10–7 mol/dm3 and 5.898 × 10–7 – 2.11 × 10–6 mol/dm3 respectively. The method is reproducible and is effective for the determination of studied phenols in the samples. [ABSTRACT FROM AUTHOR]

A highly selective, and effective poly(azomethine-urethane)-based chemosensor (HIMA) was prepared, and it used as a fluorescent sensor for the detection of Cr3+ cations in different solutions. The HIMA was prepared in two-step reactions by using hexamethylene diisocyanate, 2,4-dihydroxy benzaldehyde, and 2-aminophenol. The sensitivity and selectivity of the fluorescent probe were tested in the presence of different metal ions. The obtained findings indicated that the chemosensor exhibited a quenching effect against the only Cr3+ ion. The limit of detection (LOD) and limit of quantitation (LOQ) of the chemosensor HIMA were calculated as 7.98 × 10–7 M, and 2.42 × 10–6 M, respectively. In addition, the binding constant (Ka) of the chemosensor was calculated as 5.31 × 105 M−1. [ABSTRACT FROM AUTHOR]

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[Display omitted] • Quenching-induced interfacial amorphous layers containing atomic Ag. • Ex-TEM reveals the formation of quenching-induced amorphous layers. • Optimal sample maintains a higher capacity and longer cycle life when used in LIBs. • Post-cycle surface changes reveal the reason for high performance. The interfacial effect of nanomaterials plays a key role in their electrochemical performance when used in lithium-ion batteries (LIBs), but interfacial modification is a big challenging. Herein, a composite Fe 2 O 3 nanoparticles with atomic Ag/amorphous layers were successfully prepared by co-deposition and subsequent quenching method. Compared to pristine Fe 2 O 3 , it maintains a higher capacity and longer cycle life in LIBs, with a capacity of 1150 mAh g−1 after 600 cycles at 0.5 Ag−1, and a long 1800 cycles at a current density of 5 Ag−1 after activation. Detailed experiments and Ex-situ TEM demonstrate that the fusion of surface particles occurred after calcination and quenching treatment, resulting in amorphous layers. The amorphous layer can act as a stabilizer during cycling, which protects the overall nanospheres structure from collapsing and thus leads to ultra-long cycling life. Our findings shed light on the surface modification of nanoscale materials and provides a manner to enhance the electrochemical performance of nanomaterials for LIBs. [ABSTRACT FROM AUTHOR]

3D printing enables the customized design of implant structures for accurately regulating host responses. However, polysaccharides, as a major biomaterial category with versatile immune activities, are typically "non‐printable" due to the collapse of their filaments extruded during printing. This challenge renders their potential as immunomodulatory scaffolds underexploited. Here, inspired by the quench hardening in metal processing, a nonsolvent quenching (NSQ) strategy is innovatively designed for the 3D printing of polysaccharides. Through rapid solvent exchanging, NSQ instantly induces surface hardening to strengthen the polysaccharide filaments upon extrusion, requiring neither chemical modification nor physical blending that alters the material properties. Tested with five polysaccharides with varying physicochemical properties, NSQ prints predesigned structures at organ‐relevant scales and a long shelf‐life over 3 months. Glucomannan scaffolds, fabricated via NSQ with different grid spacings (1.5 and 2.5 cm), induce distinct host responses upon murine subcutaneous implantation—from specific carbohydrate receptor activation to differential immunocytes accumulation and tissue matrix remodeling—as mechanistically validated in wild‐type and Tlr2−/− knockout mice. Overall, NSQ as a facile and generic strategy is demonstrated to fabricate polysaccharide scaffolds with improved shape fidelity, thereby potentially unmasking their accurate immunomodulatory activities for future biomaterials design. [ABSTRACT FROM AUTHOR]

Cactus plants are prevalent in hot terrain locations. The spines in the cactus plants have an important function in preventing water evaporation. The strong pointed spines serve to distribute heat and prevent internal moisture loss owing to high heat. This paper addresses the biomimicking of a cactus plant to a reinforced concrete column. Columns are one of the most predominant elements in a structure and are responsible for maintaining the stability of the structure. Under the occurrences of fire, columns are the most affected, and the failure of the same could eventually steer to global collapse of the structure. In this study, various geometries were adopted based on the cactus plant, and the heat dissipation characteristics were studied. Finite element analysis was used to determine the optimal form based on the heat dissipation. The optimized shape was tested experimentally using a high-temperature localized heating element. Five column specimens were considered for experiments and named C (conventional nonheated column), C1 (conventional heated column), C2 (mimicked column), C3 (mimicked column with rebar in cone), and C4 (mimicked column with rebar in cone (quenching)). The heat-dissipating nature was observed, and the structural aspects were tested aftermath. The results reveal that the quenched specimen depicts better heat dissipation than the other specimens and eventually maintains the stability of the specimen throughout the height. [ABSTRACT FROM AUTHOR]

Many mechanical parts are exposed to failure as a result of mechanical stresses for design or metallurgical reasons, and the phenomenon of fatigue represents the largest area and reaches (90%) of the faults of engineering parts that are subject to periodic stresses. The risk of fatigue failure occurs without warning, so the phenomenon of fatigue resistance has taken up a large part of the research and studies concerned with the dissolution of metals. This article aims to study the effect of fatigue resistance of ASTM 1050 steel. Carbonation, repeated quenching at different temperatures (780 & 770) using seven different solutions, and tempering at repeated tempering after each quenching at temperatures (230 & 250). The stress resistance of all the studied samples decreases after the second cooling in distilled water, with the exception of the samples that were initially quenched with the same solution and then quenched again. This is one of the most significant findings. Another finding is that following a second chilling in distilled water-based solution, the resistance to fatigue stress rises, increasing by up to (8.5%) in comparison to samples that were first quenched in the same solution then diluted. [ABSTRACT FROM AUTHOR]

Abstract—The operating conditions of welded structures of shipbuilding steels, including operation at northern latitudes, determine high requirements for their quality. Materials used for such structures should guarantee stable mechanical properties, good processability during hull fabrication, and serviceability at subzero temperatures. Strain aging is due to the thermodynamic nonequilibrium of steel structure in its initial state and gradual transition to the equilibrium state provided the diffusion mobility of interstitial atoms is sufficient. In unfavorable conditions, this can lead to the degradation of properties during processing (cold straightening, bending, welding), operation, or long-term storage. The paper studies the probability of natural and artificial aging processes in steels of different chemical compositions due to bulk diffusion and carbon dislocation core diffusion (dislocation pipe diffusion). The effect of strain aging on mechanical properties and the CTOD parameter value has been examined. [ABSTRACT FROM AUTHOR]

The effectiveness of acid solutions as a quenching agent for medium carbon steel and 5083-H22 aluminium alloy was investigated in this work. The samples were quenched in different acidic solutions. Solution A consists of 99% water +1% HCl, solution B consists of 97% water +3% HCl and solution C consists of 95% water +5% HCl. Thermal camera of type FLIR T600 was used to calculate the heat transfer time between the samples and the media. The microstructural characteristics of the quenched specimens were examined with an optical microscope. The mechanical properties such as yield strength, tensile strength, elongation and hardness were obtained by the conventional method. The results reveal that the samples quenched in solutions B and C show a significant increase in terms of strength compared to samples quenched in water. The accelerated cooling in solutions B and C has a double advantage which leads to an increase in the strength of the steel without a great degradation of the deformation properties, and that's what all mechanical engineers aspire. The obtained results on 5083-H22 aluminium alloy confirm the superiority of solutions B and C over water as a quenching agent in terms of strength, hardness and elongation. [ABSTRACT FROM AUTHOR]