Increase In Peak Intensity Research Articles

Effect of annealing time on structural and optical proprieties of mercury (Hg+2) doped TiO2 thin films elaborated by sol-gel method for future photo-catalytic application

Highly nanocatalytic Hg+2-doped TiO2 thin films were synthesised by a sol-gel method, deposited on silicon, and annealed at 1000 °C for different holding times (4 h, 6 h and 8 h). The morphology, structure and optical properties of the thin films were examined by X-ray Diffraction, Raman spectroscopy, Scanning electron microscopy and UV-Vis Reflectance spectroscopy. The photocatalytic potential of the thin films was evaluated via photo-degradation of methylene-blue under UV irradiation. At higher holding times, the XRD and Raman measurement displays anatase, rutile and HgTiO3 phases, with an increase of peak intensity for anatase and rutile, and the development of an HgTiO3 phase. UV-Vis reflectance spectra showed a shift in absorbance to the visible region with decrease of band gap energies. SEM revealed an increase of highly oriented nanostructures with a preponderance of nanotubes shape. With an increase of holding time to 8 h, the Hg+2-doped TiO2 thin films showed excellent photodegradation of methylene blue under UV light for 4 h, reaching 56–72%.

Defect density and performance influenced by ozone treatment of ZnO interface in inverted organic solar cell

Zinc oxide (ZnO) has great potential as an electron transport layer (ETL) for producing efficient and stable organic solar cells. The effect of ozone treatment on ZnO working as the ETL in the organic solar cell has been studied by analyzing crystallinity, the defect density of states, and charge carrier dynamics from transient absorption spectroscopy to understand its role in the improvement in the interface between ETL and active layers. We have observed that a 10-minute continuous ozone treatment of ZnO film demonstrates improvement in its crystallinity leading to a 23% increment in short circuit current. The improvement in the crystallinity has been confirmed by the morphological and structural analysis using SEM and GIXRD. These analyses reveal the formation of a flake-like structure and an increase in peak intensity in GIXRD. It has been observed that ozone exposure has significantly affected the carrier recombination resistance, ideality factor of the device. From transient absorption spectroscopy, it has been found that for 10 min ozone-treated ZnO film has an average carrier transport time (661.79 ps), which is smallest as compared to untreated film or over treated film leading to faster carrier extraction through ETL. Further, the study of defect density of states shows that optimized ozone-treated film show 22.08% decrease in defects as compared to the control device, which primarily reflected as the improvement in the current density leading to increase in device efficiency from 2.95% to 3.75%.

Operando leaching of pre-incorporated Al and mechanism in transition-metal hybrids on carbon substrates for enhanced charge storage

Operando leaching of pre-incorporated Al and mechanism in transition-metal hybrids on carbon substrates for enhanced charge storage

Development of High-Performance Polycrystalline CVD Diamond-Coated Cutting Tools Using Femtosecond Lasers

Pulse laser grinding (PLG), an edge-shaping process, was developed previously to implement high-performance cutting tools. In this study, two femtosecond (fs) lasers with wavelengths of 1045 nm and 257 nm were used to conduct PLG on chemical vapor deposited (CVD) diamond-coated tool edges, as the fs laser is reported to have less thermal impact and the potential to improve the material crystallinity. We investigated the effects of the laser parameters on the tool edge formation and microstructural changes. The results show that although the infrared fs laser could – compared to the conventional nanosecond (ns)-laser PLG – naturally suppress surface thermal damage, the roughness of the processed surface remained relatively high with an Rz of 0.21 μm. However, under the optimal laser parameters proposed in this paper, an ultraviolet fs-laser PLG was used to obtain a much smoother edge, reducing Rz to approximately 0.08 μm. Moreover, scanning electron microscopy images indicated that the longitudinal machining marks on the ns-laser-processed surface were significantly reduced, with virtually no attached debris on the surface. Furthermore, from the Raman spectra, a significant increase in the diamond peak intensity was observed, indicating that the crystallinity of the CVD diamond (CVDD) was improved following ultraviolet-fs-laser PLG. These results demonstrate that edge shaping and structural modification of polycrystalline CVDDs can be integrated into ultraviolet-fs-laser PLG.

Interaction of Redox Probes and Ferrocene‐labelled Peptides with Lipid Bilayers Observed at Lipid Bilayer‐Modified Electrodes

AbstractGlassy carbon electrodes (GCE) modified by a bilayer of phospholipids (BLM) have been used to monitor the passage of redox probes and ferrocene‐labelled peptides across lipid membranes of an anionic (DOPG) or a zwitterionic (globally neutral DPhPC) phospholipid. The gel‐phase neutral DPhPC showed a strong association with neutral probes like ferrocene methanol but expelled positively or negatively charged species, as observed on cyclic voltammograms. Anionic DOPG underwent a strong electrostatic interaction with the positively charged hexaamine ruthenium(III) complex, leading to aggregates that caused swelling and destructuration of the BLM. With positively charged ferrocene‐tagged peptides, DOPG‐modified GCE allowed the observation of cyclic voltammograms exhibiting both a potential shift with respect to bare GCE and increased peak intensity, accounting for the slow but favored partition of the peptides between the BLM and the solution.

Structural, Optical and Morphological Properties Cadmium Sulfide Thin Films Prepared by Hydrothermal Method

In this research, pure and 4%, Mn-doped thin films of cadmium sulfide (CdS) were synthesized using a 2-hour hydrothermal process. The effect of adding the dopant concentration on thesamples' structural, morphological, and optical characteristics were investigated. The ultraviolet-visible-NIR spectrophotometer was used to investigate the optical properties. UV-Vis experiments lowered the optical bandgap with an add Mn percentage. Their optical bandgap was 2.38 eV for undoped thin films and 1.81 eV for 4% doped Mn-CdS thin films. UV-Vis spectroscopy data are in agreement with PL. FE-SEM imaging revealed morphological changes caused by the inclusion of Mn in CdS thin films. FE-SEM displays images of undopedCdS,which appear to be Nanoparticles. Morphology of the thin films has shown that the average grain size increases by the agglomeration of Nano-grains, which become clusters of particles after Mn+2incorporation. In addition, The XRD pattern revealed that prepared samples H (002)/C (111) as hexagonal and cube phases have a preferential orientation. The increase in the main diffraction peak (002) intensity with increasing Mn concentration revealed the substitution of Mn+2 with Cd+2 in the lattice. The crystallite size increased from10.74 to 11.67 nm with an Mn percentage.

Aptamer-based surface enhanced Raman spectroscopy (SERS) for the rapid detection of Salmonella Enteritidis contaminated in ground beef

A rapid and specific aptamer-based surface enhanced Raman spectroscopy (SERS) for the detection of S. enterica at a serovar level was developed. The aptamer was modified in this research with an additional short chain adenine and a fluorescein molecule. The aptamer-based SERS method could differentiate between S. enterica subsp. Enteritidis (S. Enteritidis) and S. enterica subsp. Gaminara (S. Gaminara) and allowed the in-vitro detection of S. Enteritidis at 3 log CFU/mL. The SERS characteristic peaks of the aptamer at 1184 and 730 cm−1 were used as reporters for the presence of S. Enteritidis as it binds specifically to that bacterium. Whereas, those peaks were not observed in the spectra of S. Gaminara, suggesting that the aptamer-based SERS was specific to S. Enteritidis but not S. Gaminara. The efficacy of the method to detect S. Enteritidis contaminated in ground beef (93% lean) was also determined. The observed increase of peak intensity at 726-732 cm−1 in the SERS spectra of S. Enteritidis (4 log CFU/g) inoculated samples apparently confirmed that the method can be a promising tool to specifically detect the presence of S. Enteritidis in ground beef with a total running time of 4 h.

Synthesis and characterization of Sn-doped TiO2 film for antibacterial applications

Simple sol–gel method has been exploited to deposit Sn-doped TiO2 thin films on glass substrates. The resultant coatings were characterized by X-ray diffraction (XRD), UV–visible techniques (UV–Vis), Fourier transform infrared spectroscopy (FTIR), and photoluminescence analysis (PL). The XRD pattern reveals an increase in crystallite size of the prepared samples with the increasing doping concentration. A decrease in doping concentrating resulted in the decrease in bandgap values. The different chemical bonds on these films were identified from their FTIR spectra. The photoluminescence analysis shows an increase in the emission peak intensity with increasing dopant concentration, and this can be attributed to the effect created due to surface states. The prepared samples were tested as antibacterial agent toward both Gram-positive and Gram-negative bacteria like S.aureus (Staphylococcus aureus) and E.coli (Escherichia coli), respectively. The size of the inhibition zones indicates that the sample shows maximum inhibitory property toward E.coli when compared to S.aureus.

Space charge compensation in air by counterion flow in 3D printed electrode structure

Electrospray ionization is commonly employed in modern mass spectrometry experiments for applications ranging from proteomics to environmental science and for fundamental studies of the chemical reactivity of ions. Despite the ubiquity of electrospray ionization, the total ion currents achieved using the technique remain relatively poor. While there are significant losses within the atmospheric pressure interface of the mass spectrometer (MS), many ions are lost due to space charge repulsion before ions and charged microdroplets enter the instrument. Space charge effects also limit the extent to which multiplexing of electrosprays can be used to increase ion currents. In this work, a flow of oppositely charged ions produced by atmospheric pressure chemical ionization (APCI) is employed to mitigate space charge effects in an analyte ion beam produced by nanoelectrospray ionization (nESI) as it is passed through an atmospheric pressure ion guide outside of a mass spectrometer. A decrease in the nESI beam width together with an increase in peak intensity is observed using an ion charge coupled detector in the presence of a counterflow of ions of the opposite charge. This result indicates that focusing occurs in the ion guide. Measurements of the space charge compensated ion beam using an Agilent Ultivo triple quadrupole mass spectrometer are correlated with changes in ion focusing, indicating that space charge compensation occurring before the ion beam enters the mass spectrometer can increase detected ion currents.

Saturation of electron emission with increasing ultrarelativistic intensity of the Gaussian laser pulse

Symmetric electron trajectories in the field of a Gaussian laser pulse are calculated as trajectories with compensation of the dynamic shock at the initial instant of motion. It is shown that the symmetric trajectories have an extremal property, namely, at a fixed peak intensity of the pulse, the time dependence of the electron emission intensity from a symmetric trajectory has the maximum width and amplitude compared to all other trajectories. Formation of paired peaks of electron emission intensity with changing laser pulse peak intensity is analyzed. It is found that the electron emission energy saturates with increasing peak intensity of the laser field in the ultrarelativistic region.

Low-molecular-mass labile metal pools in Escherichia coli: advances using chromatography and mass spectrometry

Labile low-molecular-mass (LMM) transition metal complexes play essential roles in metal ion trafficking, regulation, and signalling in biological systems, yet their chemical identities remain largely unknown due to their rapid ligand-exchange rates and weak M–L bonds. Here, an Escherichia coli cytosol isolation procedure was developed that was devoid of detergents, strongly coordinating buffers, and EDTA. The interaction of the metal ions from these complexes with a SEC column was minimized by pre-loading the column with 67ZnSO4 and then monitoring 66Zn and other metals by inductively coupled plasma mass spectrometry (ICP-MS) when investigating cytosolic ultrafiltration flow-through-solutions (FTSs). Endogenous cytosolic salts suppressed ESI-MS signals, making the detection of metal complexes difficult. FTSs contained ca. 80 µM Fe, 15 µM Ni, 13 µM Zn, 10 µM Cu, and 1.4 µM Mn (after correcting for dilution during cytosol isolation). FTSs exhibited 2–5 Fe, at least 2 Ni, 2–5 Zn, 2–4 Cu, and at least 2 Mn species with apparent masses between 300 and 5000 Da. Fe(ATP), Fe(GSH), and Zn(GSH) standards were passed through the column to assess their presence in FTS. Major LMM sulfur- and phosphorus-containing species were identified. These included reduced and oxidized glutathione, methionine, cysteine, orthophosphate, and common mono- and di-nucleotides such as ATP, ADP, AMP, and NADH. FTSs from cells grown in media supplemented with one of these metal salts exhibited increased peak intensity for the supplemented metal indicating that the size of the labile metal pools in E. coli is sensitive to the concentration of nutrient metals.

“Painted CNT”@Au nanoparticles: a nanohybrid electrocatalyst of direct methanol oxidation

In an era of global new energy rush, hybrid nanomaterials have raised huge interest as their components can synergistically improve the expected performances in terms of power. In this regard, direct methanol oxidation (DMO) is among the most investigated reactions for implementation in portable and other devices. Herein, we report on the design of gold-decorated multiwalled carbon nanotube-aryl nanohybrids as electrocatalyst of DMO. In a first step, Azure A (AA), Neutral Red (NR), and Congo Red (CR) dye diazonium salts were reacted with multiwalled carbon nanotubes (hereafter CNTs) to provide CNT-Dye nanoscale platforms for the immobilization of gold NPs. This step was conducted with CNT-Dye platforms evenly spread over glassy carbon (GC) electrodes. The CNT-Dye@Au nanohybrid electrode materials served for DMO electrocatalysis. Cyclic voltammograms show that bare CNT-Dye nanohybrids exhibit high electrocatalytic activity, particularly for the CNT-CR nanohybrid which returned a threefold improvement. With anchored Au NPs, a further 4 time remarkable increase in the oxidation peak intensity was achieved (i.e., about 12-fold the peak intensity recorded in the absence of any nanocatalyst). The forward to the backward anodic peak current density ratio Jf/Jb was found to be as high as is 1.68. This work provides an efficient approach for designing robust, nanohybrid electrocatalyst for DMO, based on the smart combination of CNTs, diazotized dyes, and gold NPs.Graphical abstract EMMA-D-20-00232R1

On the interaction of microstructural morphology with residual stress in fiber laser welding of austenitic stainless steel

The development of compressive residual stress is governed by the metallurgical transformation and associated microstructure, which in turn influences the mechanical properties of a welded structure. In the present work, the microstructural interaction with the thermo-mechanical performance of Yb-Fiber laser-welded austenitic stainless steel (SS304) is evaluated at different heat inputs and varying defocus distances. The interrelation between microstructural morphology and the typical pattern of residual stress is systematically investigated. The development of the thermal-metallurgical-mechanical model particularly considers the effect of solid-state phase transformation (SSPT) such that the model predicts the phase fraction and its influence on residual stress distribution. The present study exclusively focuses on the mechanism of residual stress generation as a consequence of dual-phase microstructural evolution during solidification. Low heat input (45 J/mm) leads to a high cooling rate, excellent tensile strength, and low tensile residual stress. The finite element-based thermo-mechanical model predicts the residual stress with a maximum deviation of ±50MPa compared to the experimental value. The Ferritic-austenitic (FA) mode of solidification results in the combination of skeletal and lathy δ-ferrite morphology. Increasing peak intensity of δ {110} with a cooling rate confirms the enhancement of δ-phase within the austenite matrix and restricts the complete transformation to the austenitic phase. A relatively high amount of δ-ferrite due to enriched Cr and lean Ni content at the dendritic core with fine or acicular morphology at a high cooling rate reduces the longitudinal and transverse residual stress significantly. Besides, the increasing trend of primary dendritic arm-size of δ-ferrite yields a gradual increase in residual stress.

Spectral and structural signatures of phase transformation in the charge density wave material 1T−TaS2 intercalated with triethylenediamine

Many transition-metal dichalcogenides show competing metallic, superconducting, charge density waves (CDWs), or Mott-insulating phases. Understanding the interplay between these phases is of fundamental interest. One approach to understand this relationship is to suppress one or more of the competing phases through systematic introduction of disorder. Intercalation is one of several approaches used to introduce this disorder. However, the intercalation process itself and the resulting changes in the atomic and electronic structure of the host-intercalant systems are not completely understood. Here, we characterize the structural and spectral signatures accompanying the intercalation of triethylenediamine [TED, (${\mathrm{C}}_{6}{\mathrm{H}}_{12}{\mathrm{N}}_{2}$)] into the CDW material $1T\text{\ensuremath{-}}\mathrm{Ta}{\mathrm{S}}_{2}$. Electron diffraction and electron microscopy imaging reveal that the intercalation of TED into $1T\text{\ensuremath{-}}\mathrm{Ta}{\mathrm{S}}_{2}$ leads to a change of the layer stacking in the intercalated $\mathrm{Ta}{\mathrm{S}}_{2}\text{\ensuremath{-}}\mathrm{TED}$ structure. Increased peak intensity is also observed between 3--5 eV in the valence electron-energy-loss spectra of the intercalated sample. Using electronic structure and theoretical spectra calculations we argue that these spectral features are a result of the band-structure changes due to structural phase transformation accompanying intercalation.

Identification and visualisation of microplastics / nanoplastics by Raman imaging (iii): algorithm to cross-check multi-images

We recently developed the Raman mapping image to visualise and identify microplastics / nanoplastics (Fang etal. 2020, Sobhani etal. 2020). However, when the Raman signal is low and weak, the mapping uncertainty from the individual Raman peak intensity increases and may lead to images with false positive or negative features. For real samples, even the Raman signal is high, a low signal-noise ratio still occurs and leads to the mapping uncertainty due to the high spectrum background when: the target plastic is dispersed within another material with interfering Raman peaks; materials are present that exhibit broad Raman peaks; or, materials are present that fluoresce when exposed to the excitation laser. In this study, in order to increase the mapping certainty, we advance the algorithm to combine and merge multi-images that have been simultaneously mapped at the different characteristic peaks from the Raman spectra, akin imaging via different mapping channels simultaneously. These multi-images are merged into one image via algorithms, including colour off-setting to collect signal with a higher ratio of signal-noise, logic-OR to pick up more signal, logic-AND to eliminate noise, and logic-SUBTRACT to remove image background. Specifically, two or more Raman images can act as "parent images", to merge and generate a "daughter image" via a selected algorithm, to a "granddaughter image" via a further selected algorithm, and to an "offspring image" etc. More interestingly, to validate this algorithm approach, we analyse microplastics / nanoplastics that might be generated by a laser printer in our office or home. Depending on the toner and the printer, we might print and generate millions of microplastics and nanoplastics when we print a single A4 document.

Ion irradiation-induced localized stress relaxation in W thin film revealed by cross-sectional X-ray nanodiffraction

Abstract The influence of ion irradiation on residual stress and microstructure of thin films is not fully understood. Here, 5 MeV Si2+ ions were used to irradiate a 7 µm thick tungsten film prepared by magnetron sputtering. Cross-sectional X-ray nanodiffraction and electron microscopy analyses revealed a depth-localized relaxation of in-plane compressive residual stresses from − 2.5 to − 0.75 GPa after the irradiation, which is correlated with the calculated displacements per atom within a ~2 µm thick film region. The relaxation can be explained by the irradiation-induced removal of point defects from the crystal lattice, resulting in a reduction of strains of the 3rd order, manifested by a decrease of X-ray diffraction peak broadening, an increase of peak intensities and a decrease of lattice parameter. The results indicate that ion irradiation enables control over the residual stress state at distinct depths in the material.

Temperature dependent 89Y NMR study on multiferroic YCrO3

In this manuscript, we report the 89Y NMR measurement as a function of temperature on single phase and pure polycrystalline YCrO3 sample to study the magnetism and relaxation times on a microscopic level across the magnetic transition (T N ≃ 141 K) from paramagnetic to antiferromagnetic state. The NMR peak width broadens abruptly upon crossing T N due to the onset of internal magnetic fields, while peakshift slight decreases. A slight increase and subsequent anomalous decrease in the NMR peak intensity is observed on approaching T N from 300 K. There is also a significant increase in peak width. The temperature dependence of the 89Y NMR spin–lattice relaxation rates 1/T 1 indicates a phase transition at T N which is of magnetic origin due to Cr3+ ions, with an anomalously rise of fluctuations below T N. Above T N, this spin–lattice relaxation rate can be fitted to a power-law scaling behavior 1/T 1 ∼ T β with an exponent factor β ≈ 0.8, indicates low energy spin fluctuations. Moreover, Knight shift and 1/TT 1 scales linear with the bulk susceptibility which suggests the antiferromagnetic spin fluctuation in the YCrO3 system.

Complete catalytic oxidation of formaldehyde at room temperature on MnxCo3-xO4 catalysts derived from metal-organic frameworks

Developing cost-effective non-noble catalysts for completely decomposing formaldehyde (HCHO) into harmless CO2 and H2O at room temperature remains great challenges for indoor air purification. Herein, MnxCo3-xO4 solid solutions are prepared via the calcination of metal-organic frameworks (MOFs) with different Co/Mn molar ratios. The catalyst (Mn1Co1) achieves 100 % HCHO removal at room temperature for the first time, and possesses excellent stability. During an intermittent test and a non-stop 34 -h test, the HCHO removal efficiency remains almost 100 %. The complete oxidation of HCHO is confirmed by the disappearance of HCHO peaks and the increase of CO2 peak intensity in effluent gas analysis. In situ DRIFTS results show that formate species is the main intermediate and it can be further oxidized to CO2 and H2O as final products in the presence of water vapor. The superior catalytic activity and stability of the Mn1Co1 catalyst endow its great potential in the HCHO removal application.

Highly Selective and Label-Free AuNPs Based Optical Sensor Development Significant in Smartphone Sensing of L-Lactate in Food Samples

L-lactate is an essential organic chemical in food processing, clinical, chemical, and fermentation industries. AuNPs were synthesized by chemical reduction reaction method and functionalized with 3-aminophenylboronic acid (3-APBA). The structural, morphological, FTIR, DLS, zeta potential characterization studies were performed to optimize the sensing mechanism. First time reporting facile enzyme-free sensor for the detection of L-lactate content in milk. Initially, the sensor has been optimized for nano reagent concentration, pH and time. 3-APBA@AuNPs showed a stable SPR intensity and forms a reversible tetrahedral ester complex with the analyte L-lactate (100 mM) resulting the NPs aggregation and revealing the blue shift of UV-VIS absorption wavelength (λ = 300 nm to 288 nm). Nestle- Lactogen, an India commercial milk powder has been used for the standardization study of lactate sensing. The milk samples spiked with L-Lactate (1-20mM) showed an increase in UV-VIS absorption peak intensity with concentration, and estimated the lower detection limit (LOD) = 1.1 mM using the calibration graphs. The optical sensing mechanism is explained may be due to π-π* transition of AuNPs stabilized by tetragonal complex of L-lactate bonded to 3-boronate via nucleophilic attack on boron atom. The nanosensor data was validated with commercial Megazyme kit and conventional HPLC technique. In commercial product Amul-India milk, the L-lactate value estimated as 0.678Mm with 95% correlation. Hence, the proposed sensor technique could be an alternate to the high cost conventional methods and at next level, it can be interfaced to smart phone to develop an onsite food, pharma and clinical device applications.

Desorpcija plazme pomoću masene spektrometrije kao brzi test za dijagnostiku leukemije goveda

Plasma-desorption mass spectrometry with ionization of 252Californium fission fragments (252Cf-PD MS) was used to develop an express diagnostic test for bovine leukaemia. The test is based on the mass spectrometric parameters of artificial lipid membranes formed on the gold substrate from the lipid fraction of blood cells (mainly lymphocytes), by the self-assembly technique according to the biomimetic principle. Mass spectrometric analysis of artificial lipid membranes obtained from blood plasma of control and leukemic cattle gave a reliable diagnosis of leukaemia. The basis for the diagnosis were the ionization parameters of the fragmentation of lipid molecules from normal and leukemic cell membranes. In leukemic cell membranes, separate dense areas (rafts) 200 – 300 nm in diameter, saturated with cholesterol and phospholipids, are formed. The number of rafts per unit of cell membrane of leukemic cells significantly exceeded the permitted parameters of normal cell membranes. The increased number of rafts in artificial membranes formed in the membranes of leukemic cells was reliably reflected in mass spectra, due to the 180 – 250% increase in intensity of peaks of cholesterol fragment ions in comparison to control cells.