We Can Rely on ChatGPT as an Educational Tutor: A Cross-Sectional Study of its Performance, Accuracy, and Limitations in University Admission Tests

The aim of this research was to evaluate the performance of ChatGPT in answering multiple-choice questions without images in the entrance exams to the National University of Engineering (UNI) and the Universidad Nacional Mayor de San Marcos (UNMSM) over the past five years. In this prospective exploratory study, a total of 1182 questions were gathered from the UNMSM exams and 559 questions from the UNI exams, encompassing a wide range of topics including academic aptitude, reading comprehension, humanities, and scientific knowledge. The results indicate a significant (p < 0.001) and higher proportion of correct answers for UNMSM, with 72% (853/1182) of questions answered correctly. In contrast, there is no significant difference (p = 0.168) in the proportion of correct and incorrect answers for UNI, with 52% (317/552) of questions answered correctly. Similarly, in the World History course (p = 0.037), ChatGPT achieved its highest performance at a general level, with an accuracy of 91%. However, this was not the case in the language course (p = 0.172), where it achieved the lowest score of 55%. In conclusion, to fully harness the potential of ChatGPT in the educational setting, continuous evaluation of its performance, ongoing feedback to enhance its accuracy and minimize biases, and tailored adaptations for its use in educational settings are essential

Predicted photoreflectance signatures on QD selective contacts for hot carrier solar cells

The CO2 emission of our present energy transformation processes, based mainly on burning fossil fuels, is possibly the main cause of global climatic change. The photovoltaic conversion of solar energy is a clean way of producing which for sustainability should (and most probably will) become a major source of electricity. The sun is a huge resource but relatively diluted and it is reasonable to expect that only high efficiency extraction can be cost effective for mass exploitation. New concepts are neccessary such as hot carrier solar cells

Anomaly detection on cup anemometers

The performances of two rotor-damaged commercial anemometers (Vector Instruments A100 LK) were studied. The calibration results (i.e. the transfer function) were very linear, the aerodynamic behavior being more efficient than the one shown by both anemometers equipped with undamaged rotors. No detection of the anomaly (the rotors'damage) was possible based on the calibration results. However, the Fourier analysis clearly revealed this anomaly

Optoelectronic Characterisation of Intermediate Band Solar Cells by Photoreflectance Comparison to Other Advanced Architectures.

The fabrication and design of novel materials and devices for advanced photovoltaics, like the intermediate-band solar cell (IBSC), requires the use of specific characterization tools providing information about their optoelectronic properties. We have tested the suitability of photoreflectance for the characterization of IBSC prototypes based on quantum dots and compared the results obtained with those predicted by the theory. Nonidealities in operative devices have been identified and detailed information has been obtained about the electronic structure of the materials. We have compared PR spectra of IBSCs with those obtained from alternative device architectures, namely a triple-junction solar cell and a multi-quantum well structure. Some general conclusions are drawn demonstrating the potential of the technique

Lateral absorption measurements of InAs/GaAs quantum dots stacks: Potential as intermediate band material for high efficiency solar cells

Prototypes based on InAs/GaAs QDs have been manufactured in order to realize the theoretically predicted high efficiency intermediate band solar cells (IBSCs). Unfortunately, until now, these prototypes have not yet demonstrated the expected increase in efficiency when compared with reference samples without IB material. One of the main arguments explaining this performance is the weak photon absorption in the QD-IB material, arising from a low density of QDs. In this work, we have analyzed the absorption coefficient of the IB material by developing a sample in an optical wave-guided configuration. This configuration allows us to illuminate the QDs laterally, increasing the path length for photon absorption. Using a multi-section metal contact device design, we were able to measure an absorption coefficient of ∼100 cm−1 around the band edge (∼1 eV ) defined by the transition in InAs/GaAs QD-IB materials. This figure, and its influence on the IBSC concept, is analyzed for this system

Thin Film intermediate band chalcopyrite solar cells: Theoretical Analysis of device performance and prospects for their realisation

The feasibility of implementing the intermediate-band (IB) concept into a relevant thin-film technology has been assessed. Compounds belonging to the group of I-III-VI2 chalcopyrites, currently used as absorbers in the leading thin-film technology, appear as promising candidates for the realization of IB-devices. In this paper we first analyze the expected performance of such a thin-film intermediate band solar cell (TF-IBSC) by considering different levels of idealization. In the second part of the paper some issues relevant for the practical realization of IBs in chalcopyrites are discussed and impurities acting as potential IB-precursors in the chalcopyrite sulfide host identified

Susceptibilidad antimicrobiana en cepas de pseudomonas aeruginosa aisladas de pacientes con otitis externa aguda

Las infecciones producidas por Pseudomonas aeruginosa causan altas tasas de morbimortalidad en pacientes con factores predisponentes. Se realizó un estudio descriptivo - retrospectivo en el laboratorio de Microbiología Clínica del Centro Municipal de Higiene y Epidemiología de Güines, en el período comprendido de enero del 2004 a diciembre del 2005, con el objetivo de conocer la susceptibilidad antimicrobiana en 160 cepas de Pseudomonas aeruginosa aisladas de pacientes otitis externa aguda,frente a 14 drogas antimicrobianas. Se apreció valores de sensibilidad superiores al 80% para las drogas azlocilina, ticarcilina, amikacina y gentamicina y de 71.2% para la ceftazidima. El 40.6% de las cepas presentó resistencia al trimetoprim – sulfametoxazol. Los resultados de este estudio indican que es necesario continuar la vigilancia de la susceptibilidad de los microorganismos a los agentes antibacterianos, para guiar la terapia antimicrobiana de forma empírica

Demonstration and Analysis of the Photocurrent by absorption of two sub-bandgap photons in a quantum dot intermediate band solar cell

In order to surpass the efficiency limit of single gap solar cells, intermediate band solar cells (IBSC) have to fulfill two requirements: the production of extra photocurrent by absorption of sub-bandgap photons in electronic transitions involving the intermediate band (IB) and the preservation of a high output voltage, not limited by the existence of this band. This work presents experimental evidence of the production of electron-hole pairs by absorption of two sub-bandgap photons in IBSC prototypes fabricated with InAs/GaAs QD material. The experiments were carried out at low temperatures using a specifically designed modulated photocurrent measurement set-up with two light beams. The results are analysed with the help of a simple equivalent circuit model. This analysis is also used to highlight the relevance of the two-photon mechanism demonstrated in the experiment. It is discussed that, although the absorption of sub-bandgap photons in one of the IB transitions and subsequent thermal escape of carriers is a sufficient mechanism to obtain a photocurrent enhancement, the absorption of sub-bandgap photons in both transitions involving the IB is a requisite for the voltage preservation in IBSCs

Optical Characterization of Quantum Dot Intermediate Band Solar Cells

In this paper we present an optical characterization for quantum dot intermediate band solar cells (QDIBSCs). The cells were developed by growing a stack of ten InAs/GaAs QDs layers between p and n doped GaAs conventional emitters. Electroluminescence, EL, photoreflectance, PR, and transmission electron microscopy, TEM, were applied to the samples in order to test and characterize them optically. The results, derived from the application of the different techniques, showed a good correlation. TEM images revealed a very good structural quality of the QDs, which seem to evolve in shape-strain from the bottom to the top of the stack. Corresponding to the quality observed by TEM, strong signals from EL and PR resolved unambiguously the energy band diagram of the QDIBSCs. By fitting PR data we were able to indentify the coexistence of bands and discrete energy levels coming from the IB material. The PR data evidenced also a strong electric field over the dots, attributed to the space charge region created between the p-n emitters sandwiching the IB material. From EL results, we identified the predominantly radiative nature of the IB material related energy transition

Optoelectronic evaluation of the nanostructuring approach to chalcopyrite-based intermediate band materials

Nanostructured chalcopyrite compounds have recently been proposed as absorber materials for advanced photovoltaic devices. We have used photoreflectance (PR) to evaluate the impact of interdiffusion phenomena and the presence of native defects on the optoelectronic properties of such materials. Two model material systems have been analyzed: (i) thin layers of CuGaSe2 (Eg=1.7 eV) and CuInSe2 (1.0 eV) in a wide/low/wide bandgap stack that have been grown onto GaAs(0 0 1) substrates by metalorganic chemical vapor deposition (MOCVD); and (ii) thin In2S3 samples (Eg=2.0 eV) containing small amounts of Cu that have been grown by co-evaporation (PVD) intending to form CuxInySz (Eg1.5 eV) nanoclusters into the In2S3 matrix. The results have been analyzed according to the third-derivative functional form (TDFF). The valence band structure of selenide reference samples could be resolved and uneven interdiffusion of Ga and In in the layer stack could be inferred from the shift of PR-signatures. Hints of electronic confinement associated to the transitions at the low-gap region have been found in the selenide layer stack. Regarding the sulphide system, In2S3 is characterized by the presence of native deep states, as revealed by PR. The defect structure of the compound undergoes changes when incorporating Cu and no conclusive result about the presence of ternary clusters of a distinct phase could be drawn. Interdiffusion phenomena and the presence of native defects in chalcopyrites and related compounds will determine their potential use in advanced photovoltaic devices based on nanostructures