Peak Intensity Research Articles

The Impact of π-Bridge Moiety on the Optoelectronic Properties and Photochemical Stabilities of Benzodithiophene-Based Conjugated Polymers

The stability of conjugated polymers (CPs) under exposure to light and air determines their sustainability for commercial use and their possible usage in diverse areas. The main goal of this study is to examine how changes in the π-bridge of polymers affect their electrochemical and optoelectronic properties. Furthermore, it seeks to evaluate the impact of these alterations on the photochemical durability of the polymers. Three D-π-A types of CPs were synthesized via Stille coupling. All polymers consist of the same acceptor and donor units, which were benzooxadiazole (BOz) and benzo[1,2-b:4,5-b']dithiophene (BDT), respectively, but they had different π-bridge such as thiophene (T), selenophene (Se), and thiazole (Tz).This study used a variety of spectroscopic tools such as UV-Vis, FTIR, and XPS, to investigate how photooxidation occurs. DFT calculations were used to further support the experimental results. Within a mere 30-minute timeframe, the primary absorption peak of the polymer films experienced a blue shift and a significant reduction in intensity due to being exposed to both light and air simultaneously. Despite the presence of the same electron-withdrawing group, BOz, and electron-donating group, BDT, in all polymers, the photochemical stability varies with π-bridges. T- and Se-containing conjugated polymer films (P1-T, P2-Se) exhibited a significant decrease in the intensity of their peak absorption, whereas the peak intensity and characteristics of their thiazole counterpart (P3-Tz) only showed a slight alteration after being exposed to light and air for up to 7 hours. The superior photostability of the P3-Tz polymer film can be attributed to a significantly higher HOMO level and higher band gap in comparison to P1-T and P2-Se.Comprehending the photochemical stability of these polymers is crucial for progressing their commercial uses, such as organic photovoltaics, OLEDs, and sensors. This study highlights the significance of choosing suitable π-bridges to improve the longevity and effectiveness of CPs, thus satisfying market requirements and broadening their possible applications.

A novel dual-function fluorescence sensor Eu/CDs@MOF-808 for the sensitive detection of adenosine triphosphate and uric acid

Designing and developing a reliable method for the detection of potential biomarker molecules are crucial for the early prevention and diagnosis of diseases. In this study, we present a novel functionalized metal–organic framework material (MOF-808) that is developed to construct ratiometric fluorescence sensing platforms (Eu/CDs@MOF-808) for the detection of adenosine triphosphate (ATP) and uric acid (UA). The fluorescent probe Eu/CDs@MOF-808 prepared through the in-situ encapsulation of fluorescent carbon dots (CDs) within the structure of MOF-808 exhibits excellent optical properties. Additionally, rare earth ions (Eu3+) are incorporated into the CDs@MOF-808 using a post-synthetic modification strategy. The presence of ATP significantly enhances the characteristic peak of carbon dots (CDs) at 440 nm, while the peak of Eu3+ at 614 nm remains relatively unchanged. Furthermore, the concentration of ATP exhibits a strong linear relationship with the ratiometric fluorescence intensity (F440/F614) in the concentration range of 0.5–450 μM, with a detection limit of 0.22 μM. Notably, the addition of uric acid (UA) to this fluorescence sensing platform leads to a marked reduction in the characteristic peak intensity of Eu3+, which results in a satisfactory linear relationship between the ratiometric fluorescence intensity and UA concentration in the concentration ranges of 0.04–300 μM and 300–650 μM, with a detection limit of 0.04 μM. Additionally, the fluorescent sensor has been successfully applied for the detection of ATP and UA in real serum and urine samples.

Effect of sodium gluconate addition on setting, hardening, and microstructure behaviour of hybrid alkaline mortar

In this investigation, the influence of adding 2%, 4%, 7%, and 10% sodium gluconate (SG) on the setting time of hybrid alkaline paste, and hardened and microstructure properties of hybrid alkaline mortar mixes were examined, and the results were compared with a control mix that made without addition of sodium gluconate. The hybrid alkaline paste and mortar mixes were prepared using a fixed proportion of OPC/fly ash (25%/75%), NaOH solution molarity of 9M, and sodium silicate to hydroxide ratio of 1.5. The results of this investigation found that the quick setting and abrupt loss of flowability of the control mix were improved by adding sodium gluconate, however, more promising results were observed at 7% and 10% sodium gluconate. The delay in polymerization due to lower availability of calcium ions, and adsorption of carboxyl and hydroxyl groups associated with sodium gluconate on the unreacted particles of binding materials and earlier formed products assisted in prolonging the time required for hardening. Further, the compressive strength declined at a higher dosage of sodium gluconate, however, the mortar mixes made with 2% and 4% sodium gluconate exhibited higher compressive strength than the control mix. The peak intensity of albite, nepheline, and C–S–H gel decreased at higher dosages of sodium gluconate, which was supported by a weaker microstructure characterized by more pores, micro-cracks, and partially reacted fly ash particles. Furthermore, the lower bridging oxygen content and greater Si–O–Na/ Si–O–T ratio at higher dosage of sodium gluconate confirms the delayed polymerization process.

Fabrication of Zinc Oxide Thin Films by Sol-Gel Dip Coating Process

Zinc oxide (ZnO) is a non-toxic material known for its distinctive physical and chemical properties, including a direct band gap energy of 3.37 eV and a large exciton binding energy of 60 meV, which contribute to its significant thermal and chemical stability at room temperature. Due to these characteristics, ZnO plays a critical role in various applications, such as UV light emitters, transparent conducting thin films in electronic devices, gas sensors, piezoelectric materials, transducers, and as a transparent conductive oxide (TCO) layer in thin-film photoelectrochemical cells. Numerous fabrication techniques have been employed to produce ZnO thin films. However, many of these methods require costly equipment, high vacuum environments, and elevated temperatures. In contrast, the sol-gel process stands out as a convenient, cost-effective, and versatile method for ZnO thin film fabrication. It offers advantages such as simplicity, low crystallization temperature, ease of reproducibility, molecular-level homogeneity, and precise compositional control. In this study, ZnO thin films were deposited onto Indium Tin Oxide (ITO) glass substrates using the sol-gel dip coating method, with varying preparative parameters: sol concentrations and annealing temperatures. The resulting samples were characterized using a UV-visible spectrophotometer, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray spectroscopy (EDX). The results demonstrated that the unique properties of ZnO thin films are highly dependent on the preparative parameters. Specifically, the band gap energy decreased from 3.25 eV to 3.18 eV with increasing sol concentration and also showed a similar decline with higher annealing temperatures. XRD patterns revealed a smaller full width at half maximum (FWHM) of the most intense peak (002) at higher sol concentrations and annealing temperatures, indicating an increase in crystallite size. FESEM images highlighted distinct morphological changes corresponding to the variations in sol precursor concentration and annealing temperature, while EDX analysis confirmed the formation of highly pure ZnO thin films on ITO glass substrates.

Coherent control of dressing interaction of sequential-doubly-dressed four-wave mixing

Abstract We investigate the coherent control of dressing interaction in four-wave mixing (FWM) in a Y-type four-level atomic system based on the dressed states theory. We study the density matrix equation acted by two dressing fields simultaneously governing FWM signal intensity and the eigenvalues under the dressed state formalism. It is shown that the peak position and intensity of Autler–Townes splitting both originate from the dressing interaction as the detuning of the probe field is scanned. Moreover, it is observed that the interaction could be controlled by the dressing fields. Such flexibly controlled nonlinear signal has potential applications in optical communication and quantum information processing.

Comparative Study of Raw and Water Rinsed Loa Janan’s Bituminous Coal Structure

East Kalimantan’s Coal has total humidity level at 18.21%, inherent humidity of 12.39%, fly ash content of 5.18%, volatile compounds of 38.22% and heat content of 6084 kcal/kg. However, chemical composition, functional group and crystallinity of raw and water rinsed Loa Janan bituminous coal have not been reported elsewhere. This research aims to investigate whether water rinsed treatment affects the structure of the coal or not. Coal size at 100 mesh-200 mesh is divided into 2, labeled as bituminous (a) stands for raw bituminous and bituminous (b) is for water rinsed-one. The bituminous (a) was analyzed using scanning electron miscroscopy (SEM)-energy dispersive xray (EDX), x-ray fluorescence (XRF), fourier transform infrared (FTIR) and powder x-ray diffraction (p-XRD) spectrophotometer. Meanwhile, bituminous (b) was heated at 40°C for 10 hours, cooled, rinsed using aquademin (1:5), stirred for 3 hours at 1500 rpm, and filtered. The bituminous (b) was heated at 40°C for another 10 hours and was characterized using the same technique as conducted to bituminous (a). Images revealed by SEM-EDX confirms the morphology ang topology of bituminous coal and the carbon content of them are 70.24% ± 0.87 (coal a) and 70.73% ± 0.08 (coal b). X-ray fluorescence analysis revealed that the bituminous (a) consisted of: Fe (46%), Si (21.5%), Al (5.4%) and bituminous (b): Fe (45%), Si (18.4%), Al (4.5%). There is a significant difference of their infrared spectra, both showed the peak at 1620 cm-1 (C=C) for carbon aromatic vibration. The wide area of peak at 3423 cm-1 is responsible for OH stretching vibration. Peaks intensity at 1620 cm-1 and 3420 cm-1 of bituminous (b) increased about 43.11% and 43.34%, respectively. The crystallinity degree of bituminous (b) (47.56%) is lower than that of bituminous (a) (69.72%). A sharp peak of XRD spectrum located at 2θ of 26.6o (hkl = 002) was responsible for both quartz and graphite.

Effect of intrarenal pelvic pressure on pyelo-tubular backflow and renal cortical blood perfusion during mini-percutaneous nephrolithotomy.

To investigate the effects of intrarenal pelvic pressure (IPP) on pyelo-tubular backflow and renal cortical blood perfusion during mini-percutaneous nephrolithotomy (MPCNL). Dynamic changes in pyelo-tubular backflow and renal cortical blood perfusion were studied in six patients undergoing MPCNL using dynamic contrast-enhanced ultrasonography (CEUS) and IPP monitoring. CEUS of intrarenal pelvic perfusion revealed that renal tubules began to exhibit contrast agent reflux when IPP exceeded 34 mmHg during the MPCNL procedure. There was a positive correlation between renal tubule contrast agent reflux and IPP (P < 0.05). Intravenous CEUS of renal cortical blood flow demonstrated that both intrarenal pelvic perfusion time and IPP during MPCNL significantly affected renal cortical blood perfusion. Intrarenal pelvic perfusion time and pressure were negatively correlated with contrast agent peak intensity (PI) and area under the curve (AUC) (P < 0.05). Longer intrarenal pelvic perfusion times and higher pressures resulted in decreased renal cortical blood perfusion. This study directly confirmed through dynamic CEUS and real-time IPP monitoring that an increase in IPP above the threshold of approximately 34 mmHg during MPCNL in patients leads to reflux through the renal tubules and a significant decrease in renal cortical blood perfusion. The safe upper limit for intrarenal pelvic perfusion pressure during MPCNL is approximately 34 mmHg.

Non-invasive assessment of left ventricular hemodynamic forces in hypertrophic cardiomyopathy

Abstract Background Hemodynamic force (HDF) analysis allows non-invasive measurement of intraventricular pressure gradients, portraying cyclic spatial-temporal interaction between blood and tissues. Impaired HDFs have been implicated in early detecting of adverse cardiac remodelling and treatment response in various cardiovascular disorders, providing insights into cardiac physiology not offered by traditional cardiovascular imaging (1). Mainly explored in heart failure, HDF analysis has not been previously applied to hypertrophic cardiomyopathy (HCM). Purpose To investigate differences in systo-diastolic function in HCM patients compared to healthy controls using HDF analysis. Methods Forty patients with HCM diagnosis (20 obstructive and 20 non-obstructive) were retrospectively evaluated in comparison with 22 healthy controls. Left ventricular (LV) HDFs were derived from routine transthoracic apical 4-, 2- and 3-chamber views using a dedicated software. Apical-basal HDF curves were generated, where positive deflections represent forces directed from the LV apex to the base, whilst negative ones are directed toward the apex. Amplitude and timing parameters were derived, the latter indexed to total cardiac cycle duration. Results Table 1 shows the demographic, clinical and echocardiographic characteristics of HCM compared to controls. Patients with HCM were older, had a slower heart rate due to treatment with beta-blockers, and showed hypercontractility, as expressed by higher LV ejection fraction. Compared to controls, HCM patients showed reduced LV longitudinal force, i.e. the force during the whole cardiac cycle (4.17% [2.36-5.52] vs. 6.01% [4.73-7.78], p=0.002), shorter time interval to systolic peak (0.15 [0.12-0.16] vs. 0.19 [0.17-0.20], p &amp;lt;0.001), and shorter duration of LV impulse (0.29 [0.27-0.32] vs. 0.34 [0.32-0.37], p &amp;lt;0.001) (Figure 1). However, no differences in terms of systolic force peak (p=0.283) or LV impulse intensity (p=0.689) were detected. During the transition between systole and diastole, LV suction (i.e. the interval including late systolic deceleration and early diastolic suction) was significantly longer (0.26 [0.22-0.29] vs. 0.23 [0.21-0.25], p=0.023) but less pronounced (6.30% [4.56-8.44] vs. 8.72% [6.71-12.59], p=0.005), likely reflecting a relaxation impairment from the very beginning of diastole. Such impairment was maintained during early diastolic filling, where the amplitude of the positive deceleration flow force was severely reduced in HCM compared to controls (2.98% [1.98-4.58] vs. 7.11% [4.55-8.72], p &amp;lt;0.001). Conclusions HDF analysis in HCM patients revealed unique systolic and diastolic changes reflecting faster LV contraction during systole and slower and weaker LV forces during diastole. This analysis deepens our understanding of HCM mechanic abnormalities and may help assess response to innovative treatment options.

Characterizing post-compression of mJ-level ultrafast pulses via loose focusing in a gas cell

The ability to generate high-intensity ultrashort laser pulses is a key driver for advancing the strong-field physics and its applications. Post-compression methods aim to increase the peak intensity of amplified laser pulses via spectral broadening through self-phase modulation (SPM), followed by temporal pulse compression. However, other unavoidable nonlinear self-action effects, which typically occur parallel to SPM, can lead to phase distortions and beam quality degradation. Here we study the ability to compress high-energy pulses by loose focusing in a noble gas to induce nonlinear spectral broadening, while limiting unwanted nonlinear effects such as self-focusing. We introduce ptychographic wavefront sensor and FROG measurements to identify the regimes that optimize pulse compression while maintaining high beam quality. Using a 700 mbar argon-filled double-pass-based scheme, we successfully compress 2 mJ, 170 fs, 1030 nm laser pulses to ∼35 fs, achieving 90% overall flux efficiency and excellent stability. This work provides guidelines for optimizing the compressed pulse quality and further energy scaling of double-pass-based post-compression concepts.

Investigation of Microhardness, Microstructural, Tribological, and Thermal Properties of Al7075/TiO2/Kaoline Hybrid Metal Matrix Composites Produced by Powder Metallurgy Process

The shift from traditional, single‐component metals and alloys continues, and researchers are currently investigating alternative materials. This evolution has led to the creation of innovative materials, including hybrid metal‐matrix composites. The present study aims to investigate the microstructural, surface morphological, and thermal properties of a novel Al7075/TiO2/Kaoline hybrid metal‐matrix composite prepared using high‐energy ball milling and sintering methods. In this study, phases related to the composite components are formed depending on the milling time, no undesirable phase is formed, but the peak intensities decreas as the milling time increases. Particle size increases from 63 to 215 μm with increasing milling time. Increasing the kaoline reinforcement ratio and sintering temperature increases the microhardness from 62.27 ± 2 to 75.83 ± 2 HV, and reduces the friction coefficient from 0.82 ± 0.01 to 0.62 ± 0.01. The wear rate of the composite without kaoline addition is 2.1 (mm3 m−1) × 10−3, while with 6 wt% kaoline addition, it decreases to 1.5 (mm3 m−1) × 10−3. There are no cracks in the composite other than plastic deformation due to sintering and wear. Peaks indicating endothermic and exothermic reactions during continuous heating occurr in the 635–750 °C temperature range.

Fast neutron generation with few-cycle, relativistic laser pulses at 1 Hz repetition rate

Laser-driven deuterons generate neutrons with a mean energy of 2.5 MeV, through the 2H(d,n) fusion reaction in a deuterated polyethylene (dPE) tablet. The deuterium ions are accelerated by 12 fs, 21 mJ laser pulses interacting with a 0.2 µm thin dPE foil at a peak intensity of 1018 W/cm2. The laser was operated at 1 Hz repetition rate in bursts of 75 shots. The interaction was characterized and recorded for each laser shot. The ion spectra were measured in the forward and backward directions by Thomson ion spectrometers. Neutron events were detected by a time-of-flight (ToF) system consisting of four plastic scintillators positioned at various angles around the experimental chamber. The maximum cut-off energy of the forward accelerated protons and deuterons was close to 1.4 MeV and 1 MeV, while the mean values are 428 ± 63 keV and 433 ± 80 keV, respectively. Analysis of ToF distributions from 3128 shots resulted in an average yield of 1142 ± 59 neutrons per shot in the energy range of 1.5–4 MeV. The energy distribution of forward-directed neutrons peaks between 3 and 3.5 MeV. Angular dependence analysis showed a perpendicular minimum and a maximum along the deuteron beam, consistent with the expected distribution from the literature and our simulation results.

Study of the effect of SMAW welding speed on the microstructure and crystal stability of X70 steel using X-ray diffraction

This study investigates the impact of manual electric arc welding (SMAW) speed on the microstructure of X70 steel. Welding was performed at two distinct speeds: S1 = 20 mm/min and S2 = 35 mm/min, at the COSIDER BISKRA workshop in Algeria. X-ray diffraction (XRD) analysis was conducted on the welded zones to examine crystal orientation, size, dislocation density, and structural stability across different welding areas, including the base metal (MB), heat-affected zones (HAZ1 and HAZ2), and weld zones (WZ1 and WZ2). The XRD results revealed that key crystal peaks, such as {110} and {200}, retained their positions at both welding speeds, though variations in {110} peak intensity were noted. The lower welding speed (S1) resulted in a higher heat input, which enhanced crystal stability, increased crystal size, and reduced dislocation density. On the other hand, the higher speed (S2) produced lower heat input, leading to smaller crystal sizes, increased residual stresses, and a greater number of defects due to rapid cooling. These findings underscore the critical influence of welding speed on heat input, cooling rates, and their consequent effects on microstructure. The study highlights the importance of optimizing welding parameters to balance microstructural integrity, mechanical performance, and production efficiency.

Effect of ozone gas exposure on drain current of solution-processed IGZO-TFT

The drain current (ID) of indium gallium zinc oxide thin-film transistors (IGZO-TFTs), fabricated by spin coating, decreases even when they are exposed to ozone gas at a concentration equal to or lower than 5 ppm. The ID reduction rate increases when the film thickness and the firing temperature in the spin-coating process of IGZO layer decreases. In these samples, the peak intensity ratio of the O 1s X-ray photoelectron spectroscopy (XPS) peak due to the OH group and the intensity of the infrared (IR) absorption band at 3000 cm−1–3500 cm−1 due to the OH stretching vibration increase. This indicates that OH groups within the IGZO film contribute to the ozone reaction mechanism. These findings are significant for developing high-sensitivity ozone sensors using a simpler process.

New mapping algorithm SHIM (SVD, Hilbert Identifying Method) for the extraction of phase singularities and spiral waves in cardiac arrhythmias

Background and ObjectiveAtrial fibrillation (AF) is the most prevalent cardiac arrhythmia worldwide. The effectiveness of AF ablation is restricted primarily by inaccuracies in the voltage-map videos (VMVs) acquired through multielectrode catheters. We introduce an innovative algorithm improving map quality and pinpointing the precise locations of action potential singularities. MethodsThe methodology relies on three key operations: singular value decomposition (SVD), Hilbert transform, and identifying the ridge of singularities SHIM (SVD, Hilbert, Identifying Method). To check its feasibility, this approach was used to analyze record sources from two distinct origins: a) cultures of cardiac cells, and b) real-world atrial fibrillation (AF) measurements. Efficacy is exemplified through four illustrative cases, two involving cultures of cardiac cells exposing action potential spirals, and two clinical cases involving basket catheter voltage-map videos. Resolution goodness is measured by a new method of the ratio of the peak’s height divided by the average width at half maximum or the width of the ridge-of-peaks cross-section. ResultsIn the first sample, the driving rotor became evident only following the SVD procedure stage, and its stable center became more pronounced after the H and I stages. In the case of spiral splitting, SHIM extracted all the individual tiny spiral centers. In the VMVs obtained from the basket catheters, even when the image sharpness was suboptimal, distinct singularity ridges were easily discernible with peak intensities larger than 1. ConclusionThe cumulative impact of the three stages of our analysis suggests that our novel method may excel in identifying problematic sources more effectively than previously utilized systems.

Rational Control of Maximum EMI/CPL Intensity and Wavelength of Bora[6]helicene via Polarity and Vibronic Effects.

Solvent polarity control as an efficient methodology to regulate the chiroptical properties, including spectral shape, width, intensity, wavelength, etc., has emerged as a novel frontier in optical materials design. However, the underling relationship connecting polarity to the optical property remains unclear. Herein, using state-of-the-art computations and the FC|VG model, the solvent effect on the chiroptical properties of bora[6]helicene was accurately and systematically computed to shed light on this issue. It is found that the vibronic coupling is crucial in explaining the spectral shape, width, and relative intensity of different peaks. Moreover, the intensity and position of the emission (EMI) and circularly polarized luminescence (CPL) are closely related to the polarity of the solvent. Intriguingly, we got a series of good linear relationships between polarity and EMI|CPL (|r| ≥ 0.95). Thus, this parameter can be used as a potential descriptor to estimate the intensity and position of EMI|CPL, leading to new strategies for designing fully colored fluorescent materials.

Impact of arterial system alterations due to amputation on arterial stiffness and hemodynamics: a numerical study

Subjects with amputation of the lower limbs are at increased risk of cardiovascular mortality and morbidity. We hypothesize that amputation-induced alterations in the arterial tree negatively impact arterial biomechanics, blood pressure and flow behavior. These changes may interact with other biological factors, potentially increasing cardiovascular risk. To evaluate this hypothesis regarding the purely mechanical impact of amputation on the arterial tree, we used a simulation computer model including a detailed one-dimensional (1D) arterial network model (143 arterial segments) coupled with a zero-dimensional (0D) model of the left ventricle. Our simulations included five settings of the arterial network: (1) 4-limbs control, (2) unilateral amputee (right lower limb), (3) bilateral amputee (both lower limbs), (4) trilateral amputee (lower-limbs and right upper-limb), and (5) quadrilateral amputee (lower and upper limbs). Analysis of regional stiffness, as calculated by pulse wave velocity (PWV) for large-, medium- and small-sized arteries, showed that, while aortic stiffness did not change with increasing degree of amputation, stiffness of medium and smaller-sized arteries increased with greater amputation severity. Despite a staged decrease in cardiac output, the systolic and diastolic blood pressure values increased, resulting in an increase in both central and peripheral pulse pressures but with an attenuation of pulse pressure amplification. The most significant increase in peak systolic pressure and decrease in peak systolic blood flow was observed at the site of the abdominal aorta. Wave separation analysis indicated no changes in the shape of the forward and backward wave components. However, the results from wave intensity analysis showed that with extended amputation, there was an increase in peak forward wave intensity and a rise in the inverse peak of the backward wave intensity, suggesting potential alterations in cardiac hemodynamic load. In conclusion, this simulation study showed that biomechanical and hemodynamic changes in the arterial network geometry could interact with additional risk factors to increase the cardiovascular risk in patients with amputations.

Decoding Hydrogen Desorption Kinetics in Porous Silicon: An Electrical Circuit Modeling Approach.

Solid-state hydrogen storage outperforms conventional storage methods in terms of safety and on-board applications. Porous Si (PS) is the optimized Si nanostructure with ample surface area (∼400 m2 g-1) and maximum dangling sites for hydrogenation. Though solid-state hydrogen storage in Si nanostructures, especially in porous Si, is extensively studied, the thermal desorption of hydrogen is rarely reported. This work investigates and analyzes the thermal desorption of a hydrogen-terminated PS surface using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) to optimize the temperature for efficient desorption, as FTIR is sensitive to identifying the presence of Si hydride species (SiHx). The relative peak intensities in the spectra estimate the relative hydrogen retention (γ) for the analysis of the desorption kinetics. The desorption curves are divided into two zones on the time scale: the excitation zone and the recombination zone, separated by the recombination threshold point. The initially absorbed energy breaks the Si-Hx bonds in the excitation zone to reach the recombination threshold for H2 formation. The recombination zone is further divided into two subzones: the avalanche subzone (a sudden decrease in γ indicating molecular desorption) and the saturation subzone (almost constant γ with minimal desorption). The time constant from the first-order reaction kinetic fitting of the desorption curves explores the time-temperature correlation and the barrier energy estimation for the excitation and recombination zones. The analysis identifies the critical operating point for desorption as 100 °C and 4 min, with the optimized temperature of 250 °C. This article applies an analogous electrical circuit to compare the thermal hydrogen desorption and capacitor discharge circuit for analytical convenience.

Ponderomotive potential effects on strong field two-photon double ionization in neon

Abstract In the context of the recently reported experiment on photoionization in neon atom, we theoretically study the photoionization of neon atom at a comparatively intense laser field. The calculated photoelectron spectrum for a Gaussian laser pulse show an asymmetric double peak line shape at a pulse duration of 14.2 fs and peak intensity of 1x1015 W/cm2. A systematic study clearly indicates that the ponderomotive potential of the photoelectron released during photoionization of neon is instrumental in causing the visible asymmetry. &amp;#xD; Interestingly, for similar laser parameters asymmetry in the the photoelectron spectrum gets significantly reduced for a Sech2&amp;#xD;shaped laser pulse. Time resolved photoelectron spectrum reveals that even for a Sech2 shaped laser pulse the two peak photoelectron spectrum is initially asymmetric and evolves into a symmetric line shape with increase in time. The results clearly indicate that irrespective of laser pulse shape asymmetry shows a non-linear decrease as a function of time. Our study also shows the possibility of controlling the asymmetry by varying the pulse duration. The calculations establishes a correlation between the effects of direct double ionization and ponderomotive potential on the asymmetry of the photoelectron spectrum at different pulse durations.&amp;#xD;

Spatio‐Temporal Variations and El Niño Modulation of Meteorological Droughts in Malaysia

ABSTRACTMeteorological droughts in Malaysia have significantly impacted critical sectors such as agriculture, water resources, health, the environment, tourism and various socio‐economic sectors, affecting the population's livelihood and well‐being. This study analyses drought characteristics over a 39‐year period, from 1982 to 2021, using the Standardised Precipitation Index (SPI) derived from 5‐km resolution Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS). The droughts were assessed on 3‐, 6‐, 9‐ and 12‐month timescales to investigate spatio‐temporal variations in characteristics such as frequency, duration, peak, severity and intensity. The study also provides an in‐depth analysis of large‐scale drought modulation, particularly associated with the El Niño phenomenon and its teleconnection in the Maritime Continent. Depending on the location and timescale, the number of meteorological drought occurrences varied from 10 to 22 for the 3‐month timescale and 4 to 14 for the 12‐month timescale. Generally, as the timescale of a drought increases, the peak intensity decreases, while the duration and severity increase. Additionally, drought intensity decreases over longer timescales. These characteristics show significant spatial variations. Results indicate that meteorological droughts in Malaysia were almost entirely modulated by the El Niño phenomenon through its induced teleconnection over the Maritime Continent. Drought characteristics exhibit a strong seasonality linked to changes in the Walker circulation and the strengthening and weakening of anticyclonic circulations associated with Rossby waves induced by heating in the Pacific Ocean. Very strong El Niño events had the most significant influence on the droughts. The positive Indian Ocean Dipole (pIOD) strengthened the effects of El Niño but it itself had no significant influence on the droughts. In most regions, there were no significant trends in the characteristics of meteorological droughts. However, in northeast Peninsular Malaysia and some scattered areas along the west coast of the peninsula, significant trends are observed in peak, duration and severity.

Synthesis of CdTe nanoparticles by PVD Technique and Study their Physical Properties

Nano-crystalline CdTe films were coated on a glass substrate by vacuum evaporation (PVD) technique, with the annealed temperature at (25, 100, 150, and 200 °C). The samples were examined by Uv‒visible instrument to investigate the transmittance and absorption. The dependency of the absorption coefficient (α) on the wavelength has been investigated. The X-ray diffraction revealed that cubic crystalline was obtained and the peak intensity increased as the temperature increased. The crystallite size increased during grans growth when annealed temperature increased. The estimated energy gaps of the CdTe films were 1.86, 1.87, 1.85, and 1.84 eV, due to the differences in particle sizes. Electrical characteristics have been made to detect the resistivity and conductivity and it was found that the resistivity changes directly with the increase of the energy gap and inversely with the increase in the conductivity of the CdTe films. The surface morphology was homogenous and very smooth surfaces were detected.