The micro staring hyperspectral imager can simultaneously acquire two spatial and one spectral images, and only record the external orientation elements of the entire hyperspectral image rather than the external orientation elements of each frame of the image, which avoids the geometric instability during scanning, effectively solves the problem of large geometric deformation of the small line scanning hyperspectral imager, and is suitable for the small UAV load platform with unstable attitude. At present, most of the research focuses on the radio-metric correction method of line scan hyperspectral imager. The application time of staring hyperspectral imager is short, and there is no mature data processing re-search at home and abroad, which hinders the application of UAV micro staring hyperspectral imaging system. In this paper, the calibration method of the linearity and variability of the radiation response of the micro staring hyperspectral imager on the UAV is studied, and the effectiveness of this method is quantitatively evaluated. The results show that the hyperspectral image has obvious vignetting effect and strip phenomenon before the correction of radiation response variability. After the correction, the radiation response variation coefficient of pixels in different bands decreases significantly, and the vignetting effect and image strip decrease significantly. In this paper, a multi-target radiometric calibration method is proposed, and the accuracy of radiometric calibration is verified by comparing the calibrated hyperspectral image spectrum with the measured ground object spectrum of the ground spectrometer. The results show that the calibration results of the multi-target radiometric calibration method show better results, especially for the near-infrared band, and the difference with the surface reflectance measured by the spectrometer is small.
The porous carbon/Ni nanoparticle composite was prepared by a freeze-drying method using NaCl as the template. It was applied in the effect of the concentration, adsorption time, and temperature of adsorption on the adsorption behavior. The kinetic model and the adsorption isothermic fitting results show that the adsorption behavior fits with the pseudo-secondary dynamics and the Langmuir isothermal model, indicating that the adsorption process is monolayer adsorption. Thermodynamic results indicate that the adsorption process is spontaneous physicochemical adsorption. The fitting showed that the porous carbon/Ni nanoparticle composites reach 217.17 mg·g-1, at 313 K indicates good adsorption for Congo red.
Introduction: Stenoses in the path of arteriovenous fistulas (AVF) for hemodialysis are a very prevalent problem and there is long experience in their treatment by percutaneous angioplasty (PTA). These procedures, however, involve non-negligible equipment requirements, exposure to radiation and intravenous contrast that are not beneficial for the patient and make their performance more complex. This study reviews our initial experience with Doppler ultrasound-guided angioplasty. Methods: Prospective cohort of patients with native AVF dysfunction due to significant venous stenosis treated by Doppler echo-guided PTA. AVF puncture, lesion catheterization, balloon localization and inflation, and outcome verification were performed under ultrasound guidance. Only one fistulography was performed before and another one after dilatation. As a control, the cases performed during the same period by the usual angiographic method were also collected. Results: Between February 2015 and September 2018, 51 PTAs were performed on native AVF, of which 27 were echogenic (mean age, 65.3 years; 63% male). The technical success rate was 96%. In 26% of cases, PTA was repeated due to residual stenosis after angiographic imaging. There were 7.3% periprocedural complications. 92% of the AVFs were punctured at 24 hours. Primary patency at 1 month, 6 months and 1 year was 100%, 64.8% and 43.6%, and assisted patency was 100%, 87.2% and 74.8%. There were no significant differences in immediate or late results with respect to angiographically guided AVF angioplasty. Conclusions: AVF-PTA can be performed safely and effectively guided by Doppler ultrasound, which simplifies the logistics required for its performance, although we still need to improve the capacity for early verification of the result with this imaging technique.
Contemporary infrastructure research has its origins in the late 1980s as attempts were made to measure the economic impact of public expenditures with early mixed results. In the 1990s, infrastructure assumed greater importance as a policy solution to improve economic performance in low-income economies particularly by multilateral development and official development agencies. This interest led to greater research interest with the examination of infrastructure and economic development, foreign direct investment, the role of institutions and capital markets, procurement, regional economic effects and more recently, the productivity of public investment in specific regions and industries.
This article identifies subjects that warrant further research in the future particularly the shortfall in current investment levels and how this will be met. This is a challenge for both low and high-income countries with fiscal and public debt constraints requiring governments to tap alternative sources of finance. Policy options available to government include wider use of bond markets and private participation in infrastructure provision and management. Other problems facing government include optimism bias and forecasting error that is a particular problem for projects in the transport sector.
Many other research opportunities remain to be explored and this article is designed to provide an overview of several of the subjects that would benefit from further research at the present time.
The COVID-19 epidemic caused unexpected complications, complexities and challenges in higher educational institutions (HEIs). In order to promote and strengthen the role of women leadership, this study aimed to clarify the unique challenges faced by female leaders at Saudi HEIs during the epidemic, find possible solutions to these challenges, and provide policy as well as management implications. A systematic literature review (SLR) was conducted, examining 27 records (i.e., research papers, articles and conference studies). The data were qualitatively analysed and categorized based on themes like challenges faced, opportunities recognized, and solutions proposed. Findings highlighted women leaders in Saudi HEIs grappled with multiple challenges, including technological barriers, cultural constraints, and increased workloads. Merging challenges with solvable strategies offers a forward-looking perspective, advocating for systemic changes that can shape a resilient and inclusive future for HEIs in Saudi Arabia.
This report deals synthesis of CuInGa (CIG) nano materials along with doctor blade and spin coated thin films selenization and their physical properties. The doctor blade and spin coated CIGS/SLG thin films thicknesses are obtained ̴ 2 μm and ̴ 2.95 μm. Raman spectroscopy of these thin films leads the chalcopyrite phase formation by exhibiting the peak at wave number 171 cm-1. The well developed grain growths of spin coated thin film are appeared in the surface morphology. While the grain growths developments in doctoral blade coated thin film is rather hard and fuzzy. EDS measurement recognised the existence of the compositional ratio presence of the alloying elements Cu, In. Ga and Se. The doctor blade and spin coated CIGS/SLG thin films are exhibited the UV- Visible transmission peak in the wave length range 240 nm 320 nm. The optical energy band gaps for the doctor blade and spin coated CIGS thin films are obtained 1.41eV and 1.5 eV.
Copyright © by EnPress Publisher. All rights reserved.