Layer Thickness Research Articles

The main results of the research on the cultural layer of the Samarovsky Yam settlement (Khanty-Mansiysk)

In 2016, archaeological excavations were carried out for the first time in the settlement of Samarovsky Yam (Khanty-Mansiysk) directed by I.Yu. Chikunova. The cultural layers of the 17th–20th centuries have been studied. This publication introduces the information and materials obtained during the excavations, and the results of the analysis of fish remains. Evidence has been found of the great flood of 1771, which left a thick sterile layer. This layer separated the cultural deposits of the 18th century. Stratigraphic data, coupled with the analysis of distribu-tion of various finds of wood, leather, metal, and molded, pottery and glazed ceramic ware, make it possible, in support of archival data, to trace on specific material the economic structure and changes in the level of economy of the first Russian population of Samarovsky Yam. Archaeoichthyological material is also a valuable informative archaeological source. The fish remains helped to clarify the species, size, age, and time of catching fish in the past. The study of the fish bone and scale remains made it possible to establish that whitefish species predomi-nated in the net fishing of the population of the Samarovsky Yam.

ANALYSIS OF THE EFFECTS OF SELECTED QUANTITIES ON THE FOULING OF NATURAL GAS COOLER PIPES

In this article, the effects of selected quantities on the thickness of a fouling layer that is formed on the internal surface of the pipes of natural gas (NG) coolers are discussed. Models created by applying an analytical method, a dimensional analysis, and a multiple linear regression were compared. The most complex model was the analytical model with a total of 16 relevant physical quantities. From the practicality point of view, that model was very complicated since it required applying the iterative process. The dimensional model comprised 6 similarity criteria. The difference between the fouling layer thicknesses identified analytically and those identified using a model based on a dimensional analysis did not exceed 3.06 %. Out of the total number of relevant quantities, only those that had the strongest effects on the fouling layer thickness were selected with the use of MinitabX software. Three regression models, containing 6, 5, and 4 variables, were thus created. The difference between the results obtained from the simplest regression model and the values obtained from the dimensional model amounted to a maximum of 3.20 %. The use of the presented regression models in technical practice may be recommended.

Data-driven monitoring of powder build-up for condition-based maintenance in semiconductor manufacturing facility

PurposeSemiconductor fabrication facilities often suffer from undesired particle introduction into process chambers in vacuum systems. Ideally, it is unusual to observe particles formed in the exhaust pumping line inside the chamber, but non-volatile compound products at relatively low temperatures jeopardize the vacuum pumping system, gas scrubber and the wafer-in-process. This study proposes a monitoring system for constructing a complete condition-based maintenance system for diagnosing the powder build-up within exhaust pipes used in the semiconductor manufacturing industry. This system includes ultrasonic sensors and machine learning.Design/methodology/approachEmploying ultrasonic sensors, physical and data-driven models are established. The time- or frequency-domain data acquired by the monitoring system are converted into cepstrums for modeling the powder layer thickness using machine learning.FindingsThe algorithms used in the proposed system successfully classified the thicknesses with an average accuracy of above 97%, and feature importance analysis identified the quefrency that varied with the thickness of the powder layer.Practical implicationsThe limitation of this research lies within the lab environment. It is unfortunate that the suggested method has not been evaluated in actual semiconductor manufacturing facilities, as powder build-up may take more than a few months to be called the facility maintenance. However, the submitted paper is still valid in academic and engineering aspects to be utilized in industry.Originality/valueWe modeled the system using data acquired by an ultrasonic sensor, and we constructed a data-driven model that was trained using cepstral data to replace the physical models that monitor thickness. We are the first to use ultrasound and machine learning to estimate the thickness of powder in the exhaust vacuum pumping line.

Wear behaviour and coating performance of WC–Cu composite electrodes on ZE41A magnesium alloy using electrospark deposition

ABSTRACT Magnesium alloys, being relatively softer than other structural metal, has lower hardness and is prone to wear under abrasive and frictional conditions. To enhance their wear and abrasion resistance, tungsten carbide-copper (WC-Cu) composite coating was developed on ZE41A magnesium alloy using electro-spark deposition (ESD). The composite electrodes, with combinations of 50:50 and 70:30 was prepared using powder metallurgy. ESD parameters, including spark current (SC), pulse-on time (Ton) and pulse-off time (Toff) were selected for coating. Wear behaviour was evaluated using pin-on-disc tribometer under varying sliding parameters; applied load (20N–40N), sliding speed (150 rpm–350 rpm), and sliding time (5 min–9 min). The WC70:Cu30 electrode coating exhibited the highest CR of 0.00298 gm/min and maximum layer thickness of 92.12 μm, attributed to thermal conductivity of tungsten. EDS analysis confirmed higher deposition of Cu (18.68%) and WC (3.58%) in the WC70:Cu30 coating compared to WC50:Cu50, which showed Cu (11.33%) and WC (3.06%). The lowest WR of 0.000185 mm3/min was achieved with the WC70:Cu30 coating due to higher WC deposition. SEM analysis revealed wear mechanisms such as scratch, delamination, grooves, and adhesive wear. The WC70:Cu30 composite electrode improved performance with higher CR and lower WR compared to WC50:Cu50.

Reaction Pathway Regulation for Gaseous and Liquid Products of Electrocatalytic CO2 Reduction under Adsorbate Interactions

Halide anion adsorption on transition metals can improve the performance of electrochemical CO2 reduction reaction (CO2RR), while the specific reaction mechanisms governing selective CO2RR pathways remain unclear. In this study, we demonstrate for the first time the distinct pathways for gaseous (CO) and liquid products (formate and ethanol) on the well‐defined Ag‐Cu nanostructures with controlled chlorination, respectively. We show that CO2 conversion to CO on Ag/AgCl can be tuned by adjusting the thickness of AgCl layer, achieving a Faradaic efficiency (FE) near 100% over a broad potential range in a 0.5 M KHCO3 using flow cell. In contrast, the optimized Cl‐Ag/Cu system enables the conversion of CO2 into liquid products including formate and ethanol with a total FE nearing 100%, delivering high current density under similar conditions. In situ infrared experiments and theoretical calculations reveal that the lateral adsorbate of *OCHO intermediate facilitates the thermodynamics of both the CO pathway on Cl‐Ag(111) and the formate pathway on Cl‐Ag/Cu(111) by reducing Gibbs free energy barriers of each potential‐limit step. This work uncovers the role of chlorination in the tuning of C‐bound or O‐bound intermediates during CO2RR on Ag‐Cu catalysts, determining the reaction pathway under lateral adsorbate effects.

Reaction Pathway Regulation for Gaseous and Liquid Products of Electrocatalytic CO2 Reduction under Adsorbate Interactions.

Halide anion adsorption on transition metals can improve the performance of electrochemical CO2 reduction reaction (CO2RR), while the specific reaction mechanisms governing selective CO2RR pathways remain unclear. In this study, we demonstrate for the first time the distinct pathways for gaseous (CO) and liquid products (formate and ethanol) on the well-defined Ag-Cu nanostructures with controlled chlorination, respectively. We show that CO2 conversion to CO on Ag/AgCl can be tuned by adjusting the thickness of AgCl layer, achieving a Faradaic efficiency (FE) near 100% over a broad potential range in a 0.5 M KHCO3 using flow cell. In contrast, the optimized Cl-Ag/Cu system enables the conversion of CO2 into liquid products including formate and ethanol with a total FE nearing 100%, delivering high current density under similar conditions. In situ infrared experiments and theoretical calculations reveal that the lateral adsorbate of *OCHO intermediate facilitates the thermodynamics of both the CO pathway on Cl-Ag(111) and the formate pathway on Cl-Ag/Cu(111) by reducing Gibbs free energy barriers of each potential-limit step. This work uncovers the role of chlorination in the tuning of C-bound or O-bound intermediates during CO2RR on Ag-Cu catalysts, determining the reaction pathway under lateral adsorbate effects.

Novel Investigation of a Surface Plasmon Resonance Nanostructure Employing 2D Antimonene Material for the Sensitive Detection of Foremost Human Blood Constituents

The foremost constituents of human blood are plasma, water, hemoglobin, red blood cells (RBCs), and white blood cells. The discovery of these constituents is a very imperative source to identify numerous sicknesses such as anemia, hemophilia, and myeloma. Due to its supporting real‐time explorations, great sensitivity, and simple fabrication with low cost, photonic surface plasmon resonance device (PSPRD) has a massive chance for identifying blood constituents. Kreschmann configuration is based on the projected PSPRD, and the transfer matrix technique is exhausted to analyze the reflectance of PSPRD. The thicknesses of the PSPRD layers have been adjusted to reach the best efficiency. The different constituents of blood have been inspected with their performance parameters. The topmost sensitivity 298 deg RIU−1 is triumphed for RBCs. As a result, it is anticipated that the projected PSPRD is a good candidate for the recognition and revealing of other biomolecules in the future.

Efficiency enhancement of WSe2/In2S3 solar cell by numerical modeling using SCAPS

Tungsten diselenide (WSe2), a transition metal dichalcogenide (TMDC) compound, is considered a promising material for application in thin film solar cells because of its high carrier transport, tunable band gap, and high absorption coefficient. In this work, solar cell structure comprising FTO/In2S3/WSe2 is modeled using one-dimensional solar cell capacitance simulator (SCAPS-1D) software where wide bandgap widely accessible In2S3 is used as a novel buffer layer instead of toxic CdS buffer layer for WSe2-based solar cell. The effect of thickness, doping concentrations, defect density, radiative recombination coefficient, and the electron and hole capture cross-section are analyzed and optimized. After optimizing the device, the effect of operating temperature, shunt and series resistance and back contact work function are also investigated. At an optimized WSe2 absorber layer thickness of 1.5 µm and acceptor density of 1017 cm−3, efficiency of 22.53%, fill factor of 84.98%, open circuit voltage of 1.096 V, and short circuit current density of 24.18 mA/cm2 was obtained. Additionally, a back surface field (BSF) layer comprising amorphous silicon (a-Si) of thickness 0.05 µm is introduced between the absorber layer and the back contact to lessen carrier recombination at the back surface. Therefore, the efficiency rises from 22.53% to 29.5% with a fill factor of 89.53%, open circuit voltage of 1.26 V, and short circuit current density of 26.23 mA/cm2. The simulation results suggest that WSe2-based thin-film solar cells can be designed and fabricated with high efficiency and cost advantage.

Long-Term Evaluation of Ocular Surface and Meibomian Gland Function after Laser Assisted in Situ Keratomileusis surgery.

Laser-assisted in Situ Keratomileusis (LASIK) is a common refractive surgery. But it may lead to temporary dry eye due to reversible damage to the corneal sub-basal nerve plexus. However, chronic ocular surface changes are unclear. This study reports the ocular surface changes, partial blinking rate, and meibomian gland status in eyes that underwent LASIK for at least 48 months. Cross-sectional, matched case-control comparison study, including 48 post-LASIK patients and 48 sex-, age-, smoking-, and axial length-matched healthy controls, recruited from a community eye screening program. Outcome measures include anterior segment clinical findings, keratographic and meibographic imagings. Totally 48 right eyes of 48 post-LASIK Chinese patients (39 females, 2 smokers) were analyzed with 48 right eyes of 48 matched healthy controls. The age on ocular surface examination was 50±11 years, and the axial length 26±1mm. Post-LASIK eyes had a lower quality of meibum (P=0.008) compared to healthy controls. Post-LASIK eyes were associated with a shorter Schimer test (P=0.03). The ocular surface disease index (OSDI) score was higher in post-LASIK patients (P=0.00001). Other anterior segment examination parameters, partial blinking rate, meibomian gland dropout, lipid layer thickness, non-invasive tear break-up time, and tear meniscus height were comparable between the 2 groups. Up to 75% of post-LASIK patients complained of chronic dry eye symptoms. Post-LASIK eyes were associated with a reduced aqueous tear production. Post-LASIK patients with chronic dry eye symptoms should have comprehensive ocular surface evaluation. Treatment should be commenced in patients with poor tear film stability.

Synthesis of Bimetallic Pd/Pt Truncated Nanocubes and Their Catalytic Performance in Selective Hydrogenation of Acetophenone

A series of bimetallic Pd/Pt truncated nanocube catalysts with similar morphologies and particle sizes but different platinum contents were successfully synthesized using a colloidal method without using any capping agents. Their hydrogenation properties were systematically studied and compared with their monometallic Pd or Pt nanocrystal counterparts. The results of EDX-mapping and line scanning show that platinum was relatively uniformly distributed on the surface of the Pd/Pt bimetallic nanocrystals and was not selectively deposited at the corners of the nanocrystals. The results of the selective hydrogenation of acetophenone demonstrate that the hydrogenation rate and the carbonyl selectivity of bimetallic Pd/Pt truncated nanocube catalysts are generally much higher than those of their monometallic Pd or Pt nanocrystal counterparts. It was found that the electronic interaction between palladium and platinum in the bimetallic Pd/Pt truncated nanocube catalysts and the corresponding hydrogenation activity in the selective hydrogenation of acetophenone are closely related to the molar ratio between platinum and palladium and the thickness of the platinum layer in the bimetallic Pd/Pt truncated nanocube catalyst. With an increase in the Pt/Pd molar ratio in the bimetallic Pd/Pt truncated nanocube catalysts, the activity and carbonyl selectivity in the acetophenone hydrogenation reaction increase first, reach a maximum when the molar ratio of Pt/Pd is 0.02 and the theoretical thickness of Pt is 1.3 atomic layers, and then decrease with a further increase in the Pt/Pd ratio. The hydrogenation rate of acetophenone on the Pd/Pt0.02 catalyst reaches 1.07 × 103 mmol·h−1·gcat.−1, which is 79 and 75 times larger than that of the monometallic Pd and Pt nanocrystal catalysts, respectively. The maximum yield of the target product 1-phenylethanol on the Pd/Pt0.02 truncated nanocube catalyst reaches 97.2%, which is 6.6% and 16.7% higher than that of the monometallic Pd and Pt nanocrystal catalysts, respectively.

Thin Nickel Coatings on Stainless Steel for Enhanced Oxygen Evolution and Reduced Iron Leaching in Alkaline Water Electrolysis

ABSTRACTOne of the most mature technologies for green hydrogen production is alkaline water electrolysis. However, this process is kinetically limited by the sluggish oxygen evolution reaction (OER). Improving the OER kinetics requires electrocatalysts, which can offer superior catalytic activity and stability in alkaline environments. Stainless steel (SS) has been reported as a cost‐effective and promising OER electrode due to its ability to form active Ni‐Fe oxyhydroxides during OER. However, it is limited by a high Fe‐to‐Ni ratio, leading to severe Fe‐leaching in alkaline environments. This affects not only the electrode activity and stability but can also be detrimental to the electrolyzer system. Therefore, we investigate the effect of different Ni‐coatings on both pure Ni‐ and SS‐supports on the OER activity, while monitoring the extent of Fe‐leaching during continuous operation. We show that thin layers of Ni enable enhanced OER activities compared to thicker ones. Especially, a less than 1 µm thick Ni layer on an SS‐support shows superior OER activity and stability with respect to the bare supports. X‐ray photoelectron spectroscopy reveals traces of oxidized Fe species on the catalyst surface after OER, suggesting that Fe from the SS may be incorporated into the layer during operation, forming active Ni‐Fe oxyhydroxides with a very low Fe leaching rate. Utilizing inductively coupled plasma‐optical emission spectroscopy, we prove that thin Ni layers on SS decrease Fe leaching whereas the Fe from the uncoated SS‐support dissolves into the electrolyte during operation. Thus, OER active and stable electrodes can be obtained while maintaining a low Fe concentration in the electrolyte. This is particularly relevant for application in high‐performance electrolyzer systems.

Free‐Radical Polymerization of Liquid Hydroxyethyl Methacrylate Layers Using Nanosecond Plasma Pulses

ABSTRACTPromoting both high functional group preservation and high deposition rates is a major challenge in plasma deposition. This study explores a dynamic method using nanosecond pulsed plasma discharges to polymerize thin liquid layers of 2‐hydroxyethyl methacrylate (HEMA). The influence of plasma pulse frequency (200 ns) and liquid layer thickness on chemical structure retention, polymeric growth, and thin film growth rate is examined. High‐resolution mass spectrometry (HRMS) highlights that plasma curing of liquid monomer layers achieves significantly better chemical structure preservation and polymeric growth, along with deposition rates an order of magnitude higher than traditional vapour‐phase methods. This work provides valuable insights and guidelines for plasma‐induced free‐radical polymerization of liquid layers into functional thin solid films.

Retinal Vascular Changes in Vitiligo: A Novel Approach Using OCTA

ABSTRACT Purpose This study aimed to the detect of structural and functional changes in the retina and choroid in patients with vitiligo using optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA). Materials and Methods Thirty patients with vitiligo and 30 healthy participants were enrolled in the study. Central macular thickness (CMT), retina nerve fiber layer (RNFL) thickness, choroidal thickness (CT), foveal avascular zone (FAZ) area, and superficial and deep vascular density (VD) ratios were compared between the groups. Results The mean age was 43.32 ± 12.13 and 45.90 ± 7.50 years, respectively (p = 0.435). CMT, RNFL thicknesses (except temporal quadrant), CT, superficial and deep VD, and FAZ area were similar between the two groups (p > 0.05 for all). Temporal RNFL thicknesses were lower in vitiligo patients than in control groups (p = 0.005). There was a moderate negative correlation between the duration of vitiligo disease and the mean RNFL thickness, inferior RNFL thickness, superficial total, superior, superior inner, outer, and superior outer VD values. No correlation was found between the VASI (Vitiligo area scoring index) score in vitiligo patients and OCT and OCTA values. Conclusion Although it is known that vitiligo causes melanocyte loss in ocular tissues, there was no significant effect of vitiligo on superficial and deep retinal VD. Further comprehensive studies with a larger and more diverse population of vitiligo patients are needed to explore this further.

Enhanced electrical reliability of Zr‐doped BaTiO3 nanoceramics: First‐principle calculations and experimental studies

AbstractWith the miniaturization of multilayer ceramic capacitors (MLCCs) and the increase of electric field on single‐layer dielectrics, it is essential for the development of nanograin high‐reliability dielectric materials. In this work, Zr‐doped BaTiO3‐based ceramics with an average grain size of 130–150 nm were prepared by a chemical coating method. The effects and intrinsic mechanisms of Zr concentration on microstructure, dielectric properties, and reliability were systematically investigated by theoretical calculations and experiments. Zr additives lower the migration barrier of the dopants, which consequently contributes to the formation of thick shell layers in the core‐shell structure and grain growth, affecting the temperature stability and DC bias characteristics of the dielectric constant. Owing to the large change rate of the Zr–O bond length, the introduction of Zr increases the migration barrier of oxygen vacancies. However, the decrease in the effective doping concentration of the shell part and the reduction in the number of grain boundaries of ceramics with high Zr content have a weakening effect on the inhibition of oxygen vacancy migration. An appropriate amount of Zr doping can adjust the dielectric properties and improve the reliability of BaTiO3‐based ceramics. This study provides a theoretical reference for the design of high‐quality MLCCs.

Onset and Progression of Disease in Nonhuman Primates With PDE6C Cone Disorder.

The California National Primate Research Center contains a colony of rhesus macaques with a homozygous missense mutation in PDE6C (R565Q) which causes a cone disorder similar to PDE6C achromatopsia in humans. The purposes of this study are to characterize the phenotype in PDE6C macaques in detail to determine the onset of the cone phenotype, the degree to which the phenotype progresses, if heterozygote animals have an intermediate phenotype, and if rod photoreceptor function declines over time. We analyzed spectral-domain optical coherence tomography (SD-OCT), fundus autofluorescence (FAF), and electroretinography (ERG) data from 102 eyes of 51 macaques (aged 0.25 to 16 years). Measurements of retinal layers as well as cone and rod function over time were quantitatively compared. Homozygotes as young as 3 months postnatal showed absent cone responses on electroretinogram. Infant homozygotes had reduced foveal outer nuclear layer (ONL) thickness compared with wildtype infants (P < 0.0001). Over 4 years of study, no consistent changes in retinal layer thicknesses were found within 5 adult homozygotes. However, comparisons between infants and adults revealed reductions in foveal ONL thickness suggesting that cone cells slowly degenerate as homozygotes age. The oldest homozygote (11 years) had reduced rod responses. Heterozygotes could not be distinguished from wildtypes in any parameters. These data suggest that, like humans, macaque PDE6C heterozygotes are normal, and homozygote primates have absent cone function and reduced foveal ONL thickness from infancy. Cone photoreceptors probably degenerate over time and macular atrophy can occur. Rod photoreceptor function may wane in late stages.

Influence of Selected Printing Parameters on the Mechanical Behavior of FDM-Printed ABS Specimens Using Taguchi Method

Fused deposition modelling (FDM) is the most popular additive manufacturing technique for producing prototypes in which a semi-molten thermoplastic such as acrylonitrile butadiene styrene (ABS) is extruded on a build plate in a layer wise manner from bottom to top. In FDM, the mechanical properties of a 3D-printed part are greatly affected by the build parameters such as the raster angle, extrusion temperature, layer thickness, and infill. With this, the objective of the present study is to characterize the effect of selected input build parameters on the compressive strength and impact resistance of the FDM-printed parts using orthogonal array, signal-to-noise (S/N) ratio, and analysis of variance (ANOVA). Using Taguchi’s method for the design of experiment (DOE), the optimal build parameter combinations and significant main effects were determined. Confirmation experiments were also carried out and were compared with the Taguchi-based predicted values. The experimental results are within the accepted 95% confidence interval suggesting that the optimization was successful at 5% confidence level.

Effects of Photopatterning Conditions on Azimuthal Surface Anchoring Strength

Spatially varying alignment of liquid crystals is essential for research and applications. One widely used method is based on the photopatterning of thin layers of azo-dye molecules, such as Brilliant Yellow (BY), that serve as an aligning substrate for a liquid crystal. In this study, we examine how photopatterning conditions, such as BY layer thickness (b), light intensity (I), irradiation dose, and age affect the alignment quality and the strength of the azimuthal surface anchoring. The azimuthal surface anchoring coefficient, W, is determined by analyzing the splitting of integer disclinations into half-integer disclinations at prepatterned substrates. The strongest anchoring is achieved for b in the range of 5–8 nm. W increases with the dose, and within the same dose, W increases with I. Aging of a non-irradiated BY coating above 15 days reduces W. Our study also demonstrates that sealed photopatterned cells filled with a conventional nematic preserve their alignment quality for up to four weeks, after which time W decreases. This work suggests the optimization pathways for photoalignment of nematic liquid crystals.

Use of a Novel Virtual Reality-Based Pupillography Device for Glaucoma Management: Cross-Sectional Cohort Pilot Study.

Current standard methods in monitoring glaucoma progression, like optical coherence tomography (OCT) and standard automated perimetry (SAP), have limitations in certain cases. Automated relative afferent pupillary defect (RAPD) and pupillary light reflex (PLR) testing may offer more objective alternatives. This pilot study aimed to evaluate whether RAPD could sufficiently distinguish between the two eyes in asymmetrical glaucoma, and thus could lay the foundation for using the PLR of a single eye to monitor progression longitudinally. Twenty-one patients underwent quantitative PLR measurements using a virtual reality headset. RAPD was calculated by subtracting the amplitude of PLRs between eyes. Both RAPD and relative SAP (measured using the mean defect or MD) results were correlated to the thickness of the peripapillary retinal nerve fiber layer (RNFL), as measured by OCT. Data from 18 patients was analyzed after exclusions. RAPD significantly correlated with differences between the two eyes as measured by RNFL thickness (Pearson r = 0.79, p = 0.05). MD differences correlated slightly better with RNFL differences (Pearson r = 0.87, p < 0.05). RAPD and MD combined yielded an improved prediction of RNFL differences by 5% compared to using MD only. RAPD measurements reliably detected asymmetries in optic nerve damage in glaucoma patients. SAP measurements correlated better with OCT results than RAPD results. However, SAP and RAPD combined led to an improved prediction of RNFL thickness. This could possibly allow us to use PLR only over longer periods of time to monitor glaucomatous optic nerve damage in a single eye in the future.

Efficiency Assessment of GaInp/GaAs Tandem Solar Cells: Analytical Investigation and Numerical Simulation

This paper presents a numerical simulation of a dual-junction tandem GaInp/GaAs cell made from top GaInp and bottom GaAs cells. For this purpose, we utilized a numerical simulation tool. Two methodologies were proposed, the first method consists of simulating each base layer cell of the top and bottom separately, and the second method simulated both layers in one file, to simulate both in one file. For improved electric characteristics of tandem solar cells, the current-match requirement between the top and bottom cells should be satisfied, necessitating the careful design of parameters. The top base GaInp layer thickness is adjusted to match this requirement. The solar spectrum reaching the lower cell is analytically calculated by subtracting the top cell spectrum from the total spectrum. the optimal value of short current density corresponds with a top cell base thickness of 0.8 µm, this results in an open circuit voltage of 2.45 V, a short circuit current of 15.7 Am/cm2, a fill factor of 91 %, an efficiency of 35 % for the first method and the second method used a script file designed to verify the above results and confirmed the values to be; 2.68 V open circuit voltage, 15.26 Am/cm², a short circuit current, 90 % fill factor, and 36.86 % efficiency under AM 1.5 G solar spectrum.

Land cover change and its driving factors in Siberia from 1992 to 2020.

Siberia occupies vast areas underlain by permafrost, and understanding its land cover changes is important for ecological environmental protection in a warming climate. Based on the land cover and climate datasets, we analyzed the land cover changes and their drivers in Siberia from 1992 to 2020. The results show that ① From 1992 to 2020, the areas of evergreen needleleaf trees and deciduous needleleaf trees in Siberia decreased by 9% and 2.5%, and the areas of grassland, shrub, cropland, and construction land increased by 1.5%, 14.2%, 2.8%, and 39.2%, respectively. Cropland expansion had the fastest rate of 1.85% in the continuous permafrost zone, and construction land expansion had the fastest rate of 3.07% in the non-permafrost zone. ② The center of gravity of agricultural land continues to migrate to the northeast, and the center of gravity of construction land continues to migrate to the southwest. ③ The primary drivers for the land cover changes were temperature and precipitation, and active layer thickness also affected grassland, cropland, and deciduous needleleaf trees. The correlation coefficient between active layer thickness and cropland area is 0.74 in the continuous permafrost zone. The interaction between factors is mostly manifested as a two-factor enhancement, with the highest q-value of the interaction of temperature and precipitation for explanatory power. Our results suggest that climate change and permafrost degradation significantly changed land cover in Siberia. This finding deepens our understanding of the mechanisms of land cover change under the influence of permafrost degradation and provides a new perspective on the land cover changes in permafrost regions.