Relative Band Research Articles

Iron Oxide Clusters as Electron Donors Under Light Enhance Oxygen Reduction Kinetics at Atomically Dispersed Fe for Photocatalytic CH4 Partial Oxidation

AbstractPhotocatalytic CH4 oxidation to CH3OH emerges as a promising strategy to sustainably utilize natural gas and mitigate the greenhouse effect. However, there remains a significant challenge for the synthesis of methanol by using O2 at low temperature. Inspired by the catalytic structure in soluble methane monooxygenase (MMO) and the corresponding reaction mechanism, we prepared a biomimetic photocatalyst with the decoration of Fe2O3 nanoclusters and satellite Fe single atoms immobilized on carbon nitride. The catalyst demonstrates an excellent CH3OH productivity of 5.02 mmol ⋅ gcat−1 ⋅ h−1 with CH3OH selectivity of 98.5 %. Mechanism studies reveal that the synergy between Fe2O3 nanoclusters and Fe single atoms establishes a dual‐Fe site as MMO for O2 activation and subsequent CH4 partial oxidation. Moreover, the light excitation of Fe2O3 nanoclusters with a relative narrow band gap could deliver the electrons and protons to atomic Fe that facilitating the oxygen reduction kinetics for the robust of CH3OH synthesis.

Fe2O3 Nanoflakes - WS2 Nanosheets Heterojunctions for Multi-Fold Enhancement in Photoelectrochemical Solar Energy Conversion.

Fe2O3-based photoanodes show great potential in photoelectrochemical water splitting due to their excellent stability, moderate band gap, and abundance. However, a short hole diffusion length limits its photocurrent density. Here, a multi-fold enhancement in photocurrent density from Fe2O3 nanoflakes - WS2 nanosheets heterojunction is reported. The heterojunction exhibits a synergistic photocurrent density of 0.52mA cm-2 at 1.3V (versus RHE) under AM 1.5G simulated sunlight, which is 2.23 times higher than pristine Fe2O3 nanoflakes. The Mott-Schottky and Nyquist plots indicate a higher charge density with lower charge transfer resistance at the semiconductor-electrolyte junction. The density functional theory (DFT) -based first-principles calculations are performed by designing a heterostructure between Fe2O3(110) and WS2(001) similar to the experimentally found arrangement of crystal planes. Free energy analysis and relative band extrema positions, obtained from DFT calculations and valence band spectroscopy, indicate the formation of type II heterojunction with partial oxygen terminated surface of Fe2O3. The type-II band alignment with a charge transfer of 4.8 × 10-4 e per interfacial WS2 to Fe2O3, helps in easy separation of photogenerated charges. The work establishes both an experimental design and a theoretical framework of highly crystalline nanoflakes-nanosheet heterojunctions for efficient photoelectrochemical solar energy conversion.

Advanced exploration of rare metal mineralization through integrated remote sensing and geophysical analysis of structurally-controlled hydrothermal alterations

Fusing multi-source (remote sensing and geophysical) data and diverse approaches validation in targeting hydrothermal alteration and structural anomalies enhances the potential for accurately detecting and characterizing mineralization zones. Sentinel 2 data and ASTER were processed for lithological and hydrothermal alteration mapping in the rare metal-rich Umm Naggat area (Egypt). Different image processing techniques were implemented, including false color composites, minimum noise fraction, band rationing, band math, mineral indices, relative absorption band depth, and constrained energy minimization. The rare metal-bearing Umm Naggat younger granite (NYG) pluton was lithologically discriminated and intra-differentiated to mafic-rich biotite granites, mafic-poor alkali feldspar granites, and albitized granites. Extensive hydrothermal alterations, such as albitization, ferrugination, propylitization, argillization, and phyllitization, overprint the NYG pluton. Normalized standard deviation, automatic lineament extractions, and trend analysis highlighted the key structural directions (NW, NNW, NNE, and NE) and distinguished the NYG pluton as a moderate to high structural density zone. The high structural density and intensive alteration zones are spatially associated and more localized within the NYG pluton than the surrounding rocks. Spatial overlay analysis confirmed that the hydrothermal alterations and fluid circulation systems are structurally-controlled. Furthermore, the hydrothermal alteration mapping and structural analysis outcomes were verified by combining fieldwork, slab polishing, petrographic investigations, and mineral chemistry through semi-quantitative scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and quantitative electron probe microanalysis (EPMA) analysis. As a result, the hydrothermal genesis of rare metal-bearing minerals (Nb-rutile, Nb-ilmenite, and columbite) close to or incorporated within alteration minerals (chlorite, muscovite, and hematite) is confirmed from the alteration zones (propylitic, phyllic, and ferruginated). In addition, biotite muscovitization and chloritization significantly contribute to the secondary rare metal enrichment. The current study emphasizes the extensive distribution of secondary rare metal-bearing minerals within the entire NYG pluton (not only limited to the northern albitized granite as depicted by previous studies), which might shed light on these hydrothermally-altered younger granites as a new potential source for Nb and Ta in Egypt.

An optimal demodulation frequency band selection method based on spectral coherence fault energy factor for rolling bearing fault diagnosis

Identifying a frequency band with abundant fault information from the original vibration signal under the condition of complex background noise and the interference of other rotating parts is still problematic for envelope spectrum-based bearing diagnosis. To address this issue, a new indicator called spectral coherence fault energy factor (SCFE) to is proposed to select the optimal demodulation frequency band (ODFB) under complex noise interference for bearing fault diagnosis. Firstly, the fast spectral correlation (Fast-SC) is used to analyze the raw vibration signal and generate the Spectral Coherence (SCoh) image. Then, SCFE is employed to locate the initial center frequency from the whole carrier frequency, and the threshold function is used to optimize the center frequency and bandwidth adaptively to obtain ODFB. Finally, the envelope spectrum (ES) is used to identify bearing faults. The effectiveness of the developed method in identifying the fault related frequency band and bearing fault diagnosis is validated and compared using simulated signals with different interference noises. The results of experimental signals demonstrate that the developed indicator can efficiently evaluate bearing failure information, and the presented approach can accurately discriminate the failure-related frequency band and detect different bearing faults compared with the traditional methods.

Dolomite, quartzite, and sand indices defined for PRISMA hyperspectral data. Application to the Tamlalet inlier (Eastern High Atlas, Morocco)

The present work discusses the development of three novel spectral indices for PRISMA data. The Hyperspectral Dolomite Index (HDI) using B2320nm and B2349nm bands, the Hyperspectral Sand Index (HSI) based on the visible B515nm and B596nm bands, and the Hyperspectral Quartzite Index (HQI) using a combination of Relative Band Depths in B2167nm and B2206nm bands. The outputs of the three indices are grayscale images, where the brightest pixels represent the indices target. Applying HDI on PRISMA image of Tamlalet inlier (Moroccan Eastern High Atlas) led to discriminate the dolomites from lacustrine limestones and bare soils. HDI also suggests rectifying the local geological map by replacing limestones with dolomites in Jbel Ain Chair. HQI highlights quartz-rich rocks and provides better results than ASTER TIR indices. HSI can discriminate sand dunes from bare soils without being disturbed by vegetation. Dolomite, Quartzite, and Sand Hyperspectral indices show an overall accuracy of 91.2 %, 97.8 %, and 91.5 %, respectively. These indices could be adapted to other hyperspectral data having the required wavelengths.

Exploiting the potential of images from the aster and landsat 9 satellites for the mapping of hydrothermal alteration minerals associated with mineralization in the departments of Abtouyour and Guera, located in the Chadian massif central (republic of Cha

This article deals with the use of remote sensing with Aster and Landsat 9 imagery for mapping hydrothermal alteration minerals and oxides in relation to mineralization. Aster VNIR (Visible and Near Infrared) and SWIR (Mean Infrared) data are used to calculate PCA (Principal Component Analysis), RBD (Relative Band Depth) and BR (Band Ratio). These different parameters are used to highlight the groups of hydrothermal alteration minerals and oxides. Landsat data are used for mapping lithological units using PCA and BR. The identified mining areas coincide with the gold planning sites of Toumka and Lellé and allow to know the interesting areas for future mining prospecting campaigns in the departments of Abtouyour and Guéra (Guéra province).

Tunable low-frequency broadband band gap in nonlinear locally resonant metamaterial inspired by sarcomere structure

Since traditional locally resonant metamaterials (LRMs) cannot achieve a broadband band gap in the low-frequency band, the suppression and isolation of low-frequency broadband vibration has always been a difficult problem in the field of vibration control. Therefore, in this paper, inspired by the structure of the sarcomere, a novel nonlinear LRM is proposed, aiming to open a wider band gap in the low-frequency band. Firstly, a statics model of the nonlinear local resonator (LR) is established to explore the mechanical nonlinear characteristics of the structure with different geometric parameters. And the inflection point fitting method is used to approximate the nonlinear statics model of nonlinear LR. Then a dynamics model was established, the nonlinear dispersion relationship of the infinite periodic system was obtained by Bloch's theorem and l-P perturbation method. And an analytical investigation of the theoretically calculated band gap is conducted through the band gap ratio and relative band gap width. In addition, according to the influence of different structural parameters on the real and imaginary parts of the wave vector, the regulation rules and mechanisms for nonlinear LRM to open low-frequency broadband band gaps are revealed. Finally, the Runge-Kutta method was used to numerically calculate the vibration transmissibility curve of the nonlinear LRM composed of a limited number of nonlinear LRs. And the correctness of the theoretically calculated band gap was verified. The research results provide theoretical support for the application of nonlinear LRMs in the suppression and isolation of low-frequency broadband vibrations.

Biodegradation of thermoplastic starch by a newly isolated active microbial community: Deciphering the biochemical mechanisms controlling bioprocess robustness

Defining sustainable end-of-life routes for bioplastics comprises a task of outmost importance, while biological recycling constitutes the most favorable option for several biopolymers, such as thermoplastic starch (TPS). To our knowledge, this is the first study to assess the biodegradation of TPS pellets and films in aqueous cultures employing an acclimated microbial community. Biological treatment of bioplastics displayed a two-phase pattern that included different biodegradation rates, where TPS removal in the first phase remained high and decelerated in the second phase reaching a plateau. Thus, TPS weight reduction of 14.8 % was observed using pellets following 10 d of incubation, while although films exhibited higher reduction (slightly over 30 % in 15 d), the biodegradation rate was significantly reduced thereafter. Several changes of starch related bands were detected (using FTIR) in the surface of both pellets and films during the bioprocess, indicating induction of a common biodegradation pathway. Distinct bacterial assemblages were formed during the TPS biodegradation process and statistically significant differences were detected in the abundance of several genera between the two degradation phases. Fungal communities were more stable (Fusarium and Neocosmospora were dominant at all times) and there was no effect of biofilm or degradation phase on fungal community composition. Overall, a more diverse community incorporating lower catalytic activity was gradually formed, as confirmed by the shift between k-stategist and r-stategist taxa monitored, while crystalline over amorphous regions were enhanced in the biopolymer during TPS biodegradation, responses consistent with the biodegradation rate reduction observed in the plateau stage. The study highlighted the biochemical mechanism limiting TPS biodegradation processes and the significant potential of the newly isolated community in the development of TPS waste treatment technologies.

Quantitative Electroencephalography for Predication of Neurological Dysfunction in Type A Aortic Dissection: A Prospective Observational Study.

Type A aortic dissection presents challenges with postoperative cerebral complications, and this study evaluates the predictive value of quantitative electroencephalography for perioperative brain function prognosis. Amplitude-integrated electroencephalography (aEEG) processes raw signals through filtering, amplitude integration, and time compression, displaying the data in a semilogarithmic format. Using this method, postoperative relative band power (post-RBP) α% and dynamic aEEG (ΔaEEG) grade were significantly associated with neurological dysfunction in univariate and multivariable analyses, with area under the receiver operating characteristic curve of 0.876 (95% CI, 0.825-0.926) for the combined model. Postoperative relative band power α% and ΔaEEG were significantly associated with adverse outcomes, with area under the receiver operating characteristic curve of 0.903 (95% CI, 0.835-0.971) for the combined model. Postoperative relative band power α% and ΔaEEG were significantly associated with transient neurological dysfunction and stroke, with areas under the receiver operating characteristic curve of 0.818 (95% CI, 0.760-0.876) and 0.868 (95% CI, 0.810-0.926) for transient neurological dysfunction, and 0.815 (95% CI, 0.743-0.886) and 0.831 (95% CI, 0.746-0.916) for stroke. Among 56 patients, the Alberta Stroke Program Early Computed Tomography score was superior to ΔaEEG in predicting neurological outcomes (area under the receiver operating characteristic curve of 0.872 versus 0.708 [95% CI, 0.633-0.783]; P<0.05). Perioperative quantitative electroencephalography monitoring offers valuable insights into brain function changes in patients with type A aortic dissection. ∆aEEG grades can aid in early detection of adverse outcomes, while postoperative relative band power and ∆aEEG grades predict transient neurological dysfunction. Quantitative electroencephalography can assist cardiac surgeons in assessing brain function and improving outcomes in patients with type A aortic dissection. URL: https://www.chictr.org.cn; Unique identifier: ChiCTR2200055980.

Machine learning based classification of presence utilizing psychophysiological signals in immersive virtual environments

In Virtual Reality (VR), a higher level of presence positively influences the experience and engagement of a user. There are several parameters that are responsible for generating different levels of presence in VR, including but not limited to, graphical fidelity, multi-sensory stimuli, and embodiment. However, standard methods of measuring presence, including self-reported questionnaires, are biased. This research focuses on developing a robust model, via machine learning, to detect different levels of presence in VR using multimodal neurological and physiological signals, including electroencephalography and electrodermal activity. An experiment has been undertaken whereby participants (N = 22) were each exposed to three different levels of presence (high, medium, and low) in a random order in VR. Four parameters within each level, including graphics fidelity, audio cues, latency, and embodiment with haptic feedback, were systematically manipulated to differentiate the levels. A number of multi-class classifiers were evaluated within a three-class classification problem, using a One-vs-Rest approach, including Support Vector Machine, k-Nearest Neighbour, Extra Gradient Boosting, Random Forest, Logistic Regression, and Multiple Layer Perceptron. Results demonstrated that the Multiple Layer Perceptron model obtained the highest macro average accuracy of 93±0.03%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$93\\pm 0.03\\%$$\\end{document}. Posthoc analysis revealed that relative band power, which is expressed as the ratio of power in a specific frequency band to the total baseline power, in both the frontal and parietal regions, including beta over theta and alpha ratio, and differential entropy were most significant in detecting different levels of presence.

Trichloroethylene and tetrachloroethylene adsorption studies on α-antimony phosphorous nanosheets – A first-principles study

In recent days, monolayer materials have been pioneering research to detect different kinds of toxic pollutants in the air atmosphere. In this work, we utilised alpha-phase antimony phosphorous (α-SbP) as a sensing substrate to detect the chlorinated ethylene molecules such as trichloroethylene (TCE) and tetrachloroethylene (PCE). Initially, the structural stability including the dynamical firmness of α-SbP is validated by cohesive energy and phonon band spectrum. Furthermore, the electronic characteristic of pristine α-SbP is investigated by band structure and projected density of states (PDOS) maps. The calculated energy gap of α-SbP is observed to be 1.162 eV which validates the semiconductor behaviour. Importantly, the interaction behavior of TCE and PCE on α-SbP is explored with regard to Mulliken charge analysis, adsorption energy, and relative band gap changes. The adsorption-energy values are recorded within the physisorption scope (−0.027 eV to −0.593 eV). Thus, the proposed α-SbP is a good candidate for the detection of TCE and PCE in the air atmosphere.

The strength of anticipated distractors shapes EEG alpha and theta oscillations in a Working Memory task

Working Memory (WM) requires maintenance of task-relevant information and suppression of task-irrelevant/distracting information. Alpha and theta oscillations have been extensively investigated in relation to WM. However, studies that examine both theta and alpha bands in relation to distractors, encompassing not only power modulation but also connectivity modulation, remain scarce. Here, we depicted, at the EEG-source level, the increase in power and connectivity in theta and alpha bands induced by strong relative to weak distractors during a visual Sternberg-like WM task involving the encoding of verbal items. During retention, a strong or weak distractor was presented, predictable in time and nature. Analysis focused on the encoding and retention phases before distractor presentation. Theta and alpha power were computed in cortical regions of interest, and connectivity networks estimated via spectral Granger causality and synthetized using in/out degree indices. The following modulations were observed for strong vs. weak distractors. In theta band during encoding, the power in frontal regions increased, together with frontal-to-frontal and bottom-up occipital-to-temporal-to-frontal connectivity; even during retention, bottom-up theta connectivity increased. In alpha band during retention, but not during encoding, the power in temporal-occipital regions increased, together with top-down frontal-to-occipital and temporal-to-occipital connectivity. From our results, we postulate a proactive cooperation between theta and alpha mechanisms: the first would mediate enhancement of target representation both during encoding and retention, and the second would mediate increased inhibition of sensory areas during retention only, to suppress the processing of imminent distractor without interfering with the processing of ongoing target stimulus during encoding.

Effects of low dose skin tissue derived peptides on the function and collagen expression of keloid fibroblasts

This study aims to investigate the effects of the skin tissue derived peptides on proliferation, apoptosis, migration and collagen expressions in keloid fibroblasts. From January 2015 to January 2017, patients with hypertrophic scar who underwent surgical excision in department of plastic surgery of Nanjing maternal and child health hospital were included in this retrospective study. Four peptides were selected from the differential peptides between human hypertrophic scar and normal skin tissue. They were named as peptide deregulated in hypertrophic scar 2-5 (PDHPS2-5). Bioinformatics and functional analysis were performed. A low dose of 10 μmol/L of four peptides were respectively added to the culture medium of human primary keloid fibroblasts for 24 h. Cell counting kit-8 (CCK-8) were used to detect the changes in cell viability. Cell apoptosis was detected by flow cytometry. Cell migration ability was checked by Transwell chamber. The protein expressions of collagen COL1A2 (Collagen type I alpha 2) and the myofibroblast marker gene ACTA2 (Actin alpha 2) were analyzed by Western blot. The results showed that bioinformatics prediction analysis revealed that peptide PDHPS4 has the longest half-life and the highest thermal stability. Compared with the control group, low dose of four peptides had no significant effect on the survival rate and apoptosis of keloid fibroblasts tested by CCK-8 assay and flowcytometry. Transwell analysis showed that one peptides (PDHPS5) can significantly inhibit the cell migration ability (The optical density value in Control is 0.81±0.11, in PDHPS5 is 0.27±0.03, t=8.61, P=0.001). Western blot analysis showed that four peptides (PDHPS2, PDHPS3, PDHPS4, PDHPS5) can significantly inhibit the protein expressions of COL1A2 (The relative protein band intensity in Control is 1.02±0.02, in PDHPS2 is 0.21±0.04, in PDHPS3 is 0.26±0.03, in PDHPS4 is 0.53±0.04, in PDHPS5 is 0.73±0.04, t=31.38, 38.54, 18.88, 11.07 respectively, all P value are less than 0.01). Three peptides (PDHPS2, PDHPS3, PDHPS5) can significantly inhibit the protein expressions of ACTA2 (The relative protein band intensity in Control is 1.02±0.02, in PDHPS2 is 0.64±0.05, in PDHPS3 is 0.77±0.06, in PDHPS5 is 0.47±0.07, t=12.08, 6.38, 14.06 respectively, all P value are less than 0.01). In conclusion, the differentially expressed peptides in human hypertrophic scar tissue can affect the function of keloid fibroblasts and collagen expressions to varying degrees. Among them, two peptides (PDHPS2,PDHPS3) significantly inhibit the protein expressions of COL1A2 and ACTA2. The peptide PDHPS5 has high stability, significantly suppresses cell migration, and reduces the protein expressions of COL1A2 and ACTA2, which may provide a new strategy for scar prevention and treatment.

EEG Functional Connectivity Differences Predict Future Conversion to Dementia in Mild Cognitive Impairment With Lewy Body or Alzheimer Disease.

Predicting which individuals may convert to dementia from mild cognitive impairment (MCI) remains difficult in clinical practice. Electroencephalography (EEG) is a widely available investigation but there is limited research exploring EEG connectivity differences in patients with MCI who convert to dementia. Participants with a diagnosis of MCI due to Alzheimer's disease (MCI-AD) or Lewy body disease (MCI-LB) underwent resting state EEG recording. They were followed up annually with a review of the clinical diagnosis (n=66). Participants with a diagnosis of dementia at year 1 or year 2 follow up were classed as converters (n=23) and those with a diagnosis of MCI at year 2 were classed as stable (n=43). We used phase lag index (PLI) to estimate functional connectivity as well as analysing dominant frequency (DF) and relative band power. The Network-based statistic (NBS) toolbox was used to assess differences in network topology. The converting group had reduced DF (U=285.5, p=0.005) and increased relative pre-alpha power (U=702, p=0.005) consistent with previous findings. PLI showed reduced average beta band synchrony in the converting group (U=311, p=0.014) as well as significant differences in alpha and beta network topology. Logistic regression models using regional beta PLI values revealed that right central to right lateral (Sens=56.5%, Spec=86.0%, -2LL=72.48, p=0.017) and left central to right lateral (Sens=47.8%, Spec=81.4%, -2LL=71.37, p=0.012) had the best classification accuracy and fit when adjusted for age and MMSE score. Patients with MCI who convert to dementia have significant differences in EEG frequency, average connectivity and network topology prior to the onset of dementia. The MCI group is clinically heterogeneous and have underlying physiological differences that may be driving the progression of cognitive symptoms. EEG connectivity could be useful to predict which patients with MCI-AD and MCI-LB convert to dementia, regardless of the neurodegenerative aetiology.

Allethrin and tetramethrin molecular adsorption on novel phosphoaluminane nanosheet based on first-principles investigation

Allethrin and tetramethrin are both active ingredients in the production of insect spray. Being very toxic in nature, the inhalation of allethrin and tetramethrin causes various side effects in human beings. For the detection of allethrin and tetramethrin, the effectiveness of the base material phosphoaluminane is studied in the current work with the help of the density functional theory (DFT) calculations. The stability of phosphoaluminane is ensured with the support of formation energy and phonon band spectrum. The electronic properties of phosphoaluminane are systematically investigated using band structure and projected density of states (PDOS) maps. The obtained band gap value of phosphoaluminane is 1.716 eV, which confirms that the base material has semiconducting properties. The adsorption behaviour of target molecules allethrin and tetramethrin on phosphoaluminane are explored with prominent parameters including adsorption energy, Mulliken population analysis, and relative band gap changes. The adsorption energy range is recorded to be in the scope of −0.237 eV to −0.597 eV. From the results, it is clear that both allethrin and tetramethrin are physisorbed on phosphoaluminane sheets. Hence, novel phosphoaluminane nanosheets can be utilised as a sensing material for allethrin and tetramethrin.

Hex-star phosphorene nanosheets as sequencing material for DNA/RNA strands – A first-principles investigation

In this study, we utilised hex-star phosphorene as the main detecting material to identify the nucleobases. Nucleobases, being crucial carriers of hereditary information are identified through specific hydrogen bonding and steric interactions such as adenine pairing with thymine (or) uracil and guanine pairing with cytosine. The stable hex-star phosphorene possesses negative formation energy of −5.194 eV. The hex-star phosphorene exhibits a semiconductor nature with an energy band gap of 1.658 eV, which is deployed as the adsorbing substrate for nucleobases. Based on the Mulliken charge analysis, adsorption energy, relative band gap variation, and the detection efficiency of hex-star phosphorene towards nucleobases are examined. The outcome confirms the physisorption of nucleobases on hex-star phosphorene and strongly supports that hex-star phosphorene can be used as sequencing material for DNA and RNA.

Integrating remote sensing and geophysical data for mapping potential gold mineralization localities at Abu Marawat area, central Eastern Desert, Egypt

Abu Marawat area in the Central Eastern Desert of Egypt is a very promising mineralization district located in the Golden Triangle area. The current study provides an integrated approach from multisource datasets including; remote sensing, airborne geophysical spectrometry and magnetic data supported by field studies and spectroscopic analyses for delineating potential mineralization localities. Several remote sensing techniques were adopted including; Band Ratios, Relative Band Depth, Mineralogical Indices, Spectral Angle Mapper, and Constrained Energy Minimization. These techniques showed that the alteration mineral assemblage is mainly, kaolinite, sericite, and iron oxides, with less abundant chlorite, epidote, and carbonates. In addition, the radiometry data were processed to map the localities with the highest possibility of potassic alteration abundance by integrating the potassium distribution, K/eTh ratio, and the F-parameter maps. The surface and subsurface linear structural features were also mapped using Digital Elevation Model (DEM) and aeromagnetic data, respectively. The surface linear structures were found exhibiting E-W and NE-SW trends, while, the subsurface structures showed dominant NW–SE trend. All the depicted fault trends match well with the local and regional geological and tectonic setting of the study area suggesting structural control on the mineralization in this area. Integration between the results obtained from both the remote sensing and the geophysical data was conducted by a GIS weighted overlay model. The obtained mineralization potentiality map highlights eight potential localities for mineralization. The accuracy of the adopted methodology was demonstrated through fieldwork and spectral analyses; several alteration indicators were observed, including quartz veins, iron oxides, kaolinite, malachite, montmorillonite, chlorite, talc, and sericite alteration indicator minerals. The adopted remote sensing-geophysical approach showed being very effective for mapping the hydrothermal gold-related alteration zones, and is recommended for other similar investigations.

Gas-Phase Characterization of Redox-Active Manganese Complexes.

Manganese complexes exhibit a rich redox chemistry, usually accompanied by structural reorganization during the redox processes often followed by ligand dissociation or association. The push-pull ligand 2,6-diguanidylpyridine (dgpy) stabilizes manganese in the oxidation states +II, +III, and + IV in the complexes [Mn(dgpy)2]n+ (n = 2-4) without change in the coordination sphere in the condensed phase [Heinze et al., Inorganic Chemistry, 2022, 61, 14616]. In the condensed phase, the manganese(IV) complex is a very strong oxidant. In the present work, we investigate the stability and redox activity of the MnIV complex and its counterion (PF6-) adducts in the gas phase, using two modified 3D Paul ion trap mass spectrometers. Six different cationic species of the type [Mnx(dgpy)2(PF6)y]n+ (x = II, III, IV, y = 0-3, n = 1-3) could be observed for the three oxidation states MnIV, MnIII, and MnII, of which one observed complex also contains a reduced dgpy ligand. MnII species showed the highest relative stability in collision induced dissociation and UV/vis photo dissociation experiments. The lowest stability is observed in the presence of one or more counterions, which correlates to a lower total charge n+. Gas phase UV/vis spectra show similar features as the condensed phase spectra only differing in relative band intensities. The strongly oxidizing MnIV complex reacts with triethylamine (NEt3) in the gas phase to give MnIII, while MnIII species show little reactivity toward NEt3.

Wideband isolator based on one-way surface magnetoplasmons with ultra-high isolation

In this paper, we present a new type of isolator based on one-way surface magnetoplasmons (SMPs) at microwave frequencies, and it is the first time that an experimental prototype of isolator with wideband and ultra-high isolation is realized using SMP waveguide. The proposed model with gyromagnetic and dielectric layers is systematically analyzed to obtain the dispersion properties of all the possible modes, and a one-way SMP mode is found to have the unidirectional transmission property. In simulation and experiment with metallic waveguide loaded with yttrium–iron–garnet (YIG) ferrite, the scattering parameters and the field distributions agree well with the analysis and verify the one-way transmission property. The isolation is found to be as high as 80 dB and the typical value of insertion loss is 1 dB. Besides, the one-way transmission band can be controlled by changing the magnetic bias. From theoretical analysis and simulation, it is found that with a tiny value of 10 Oe of the magnetic bias, the relative bandwidth can be tuned to be greater than 50%. Compared with conventional isolators, this one-way SMP isolator has the advantages of ultra-high isolation, wide relative frequency band, and requires much smaller bias field, which has promising potential in non-reciprocal applications.

On the effective vibrational temperature of the source using (2)3∏ - X3∏ system of GeC molecule

In this work, the experimental potential energy curves for (2)3Π and X3Π electronic states of GeC molecule have been constructed by using Rydberg-Klein-Rees (RKR) method. The radiative transition parameters viz., Franck-Condon (FC) factor, r-centroid, electronic transition moment, band strength, relative band strength, Einstein coefficients, radiative lifetime and oscillator strength for the (2)3Π−X3Π system of GeC molecule have been estimated for the experimentally observed vibrational levels from Rydberg-Klein-Rees (RKR) potential and the estimated values are tabulated. The estimated effective vibrational temperature found as 5628 K for the (2)3Π−X3Π system of GeC molecule. The radiative transition parameters and effective vibrational temperature are evident that the possible presence of GeC molecule in solar and sunspots atmosphere. Further, these parameters are employed in rationalizations of astrochemical and astrophysical observations.