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Growth mode in heteroepitaxial system from nano- and macro- theoretical viewpoints
摘要： Growth mode in semiconductor heteroepitaxial system such as InAs/GaAs is systematically investigated from nano- and macro-theoretical viewpoints, where ab initio, empirical interatomic potential, and phenomenological macroscopic theory are used. The nanoscopic theories clarify that the misfit dislocation (MD) formation energy depends on orientation such as 1.14 eV/? for (001), 0.96 eV/? for (110), and 0.68 eV/? for (111)A. On the basis of these calculated results, growth mode boundary between two-demensional with MD formation (2D-MD) and three-dimensional Stranski-Krastanov island (3D-SK) growth modes is successfully determined as funcions of surface energy and degree of strain relaxation. The region of 3D-SK growth mode is the largest for (001) while (111)A has the largest 2D-MD region and that for (110) is in between. Using surface energy obtained by ab initio calculations and the degree of strain relaxation estimated by continuum elasticity theory, it is found that (001) favors the 3D-SK growth mode while 2D-MD growth mode appears for (110) and (111)A. It shoud be noted that the (110) data stay near the growth mode boundary between 3D-SK and 2D-MD growth modes. Reflecting this, growth mode transition from 3D-SK to 2D-MD occurs for (110) due to In0.25Ga0.75As layer insertion at the interface that decreases surface energy from 50.9 meV/?2 to 49.1 meV/?2. Versatility of this approach is discussed by comparing with experimental findings.
关键词： A1 Computer simulation,A1 Growth models,B2 Semiconducting indium compounds,A3 Molecular beam epitaxy,A1 Surface structure
更新于2025-09-19 17:15:36
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First-principles investigation of the double ESIPT process in a thiophene-based dye
摘要： The unusual emission spectrum of 2,5-bis(benzoxazol-2-yl)thiophene-3,4-diol (BBTP) is investigated. The complexity of the emission spectrum of this dye is due to the presence of two excited-state intramolecular proton transfer (ESIPT) sites that give rise to three non-equivalent tautomers. The different maxima were experimentally attributed to the initial double enol form, the single ESIPT enol–keto tautomer, and the double ESIPT structure. Our simulations, based on Time Dependent Density Functional Theory (TD-DFT) and post Hartree–Fock methods [ADC(2) and CC2] coupled to different schemes to include the solvent polarisation response, are able to reproduce the key experimental outcomes. Moreover, we prove that for solving the inconsistencies present in earlier theoretical studies, a state-specific solvation approach is needed: one should go beyond the standard linear-response scheme in polarisable dielectric models. Finally, using a validated model, we explore the impact of substitution by donor and acceptor groups.
关键词： TD-DFT,emission spectrum,BBTP,CC2,tautomers,ADC(2),ESIPT,solvent models
更新于2025-09-19 17:15:36
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Impact of compensation mechanisms for PV generation on residential consumers and shared net metering model for developing nations: a case study of India
摘要： The present work examines the impact on consumer electricity bills under five different cases designed on different compensation mechanisms to evaluate PV generation units for 120 residential consumers in Kharagpur, West Bengal, for assessing the pertinence of energy policy to be introduced for encouraging rooftop PV in India. The consumers are categorized based on their lifestyles. It is found that lower the size of the panel, lower is the savings leading to a decrease in the attractiveness of a rooftop PV system for a residential consumer. Also, the compensation mechanism and injection tariff play a crucial role in making a rooftop PV system feasible for a residential consumer. It is observed that the achieved savings of a consumer is a function of compensation mechanism and seasonal load pattern of a consumer. A shared distributed net metering model is proposed as an alternative to the individual rooftop PV systems, to mitigate the issues related to shading, land and financial feasibility of a PV system for small residential consumers. The results of the simulation analysis based on the model indicate a high positive net present value and an acceptable payback period, which makes the model feasible. The proposed model is found to be more scalable and economically viable for a developing nation like India. Net metering policy, being in its nascent stage in India, needs to be revisited to incorporate innovative tools and mechanisms to deliver the goods to the large section of the population.
关键词： PV compensation mechanism,Shared Net Metering Models,India,Residential consumer,Net Metering Policy
更新于2025-09-19 17:15:36
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The Efficiency of Verteporfin as a Therapeutic Option in Pre-Clinical Models of Melanoma
摘要： Yes Associated Protein 1 (YAP) and Transcriptional coactivator with PDZ-Binding Motif (TAZ) have gained notoriety for their ability to drive tumor initiation and progression in a wide variety of cancers, including melanoma. YAP and TAZ act as drivers of melanoma through its interaction with the TEAD family of transcription factors. Verteporfin is a benzoporphyrin derivative that is used clinically for photodynamic treatment of macular degeneration. Recently it has emerged as a potential inhibitor of YAP/TAZ-TEAD interaction independent of light activation. In this study we determine if verteporfin has clinical potential by testing this compound on human melanoma cell cultures and in a clinically significant mouse model, BrafCA; Tyr-CreERT2; Ptenf/f, which parallels human melanoma in terms of disease progression, genetics, and histopathology. In culture, Verteporfin treatment induces a rapid drop in YAP and TAZ protein levels and cell numbers. In the transgenic model, utilizing drug levels that correspond to previously determined safe doses in human patients and with a dosing regimen calculated in this study, Verteporfin did not inhibit melanoma initiation or progression in comparison to mock treated controls. Taken together, our study suggests that although Verteporfin induces YAP/TAZ degradation in melanoma cell lines, Verteporfin was not effective as a YAP/TAZ-TEAD specific inhibitor of melanoma in our studies that aimed to mimic conditions found in clinic in terms of treatment regimen and disease model.
关键词： TAZ,Verteporfin,hippo pathway,mouse models,melanoma,YAP
更新于2025-09-19 17:15:36
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A predictive screening tool to detect diabetic retinopathy or macular edema in primary health care: construction, validation and implementation on a mobile application
摘要： The most described techniques used to detect diabetic retinopathy and diabetic macular edema have to be interpreted correctly, such that a person not specialized in ophthalmology, as is usually the case of a primary care physician, may experience difficulties with their interpretation; therefore we constructed, validated and implemented as a mobile app a new tool to detect diabetic retinopathy or diabetic macular edema (DRDME) using simple objective variables. We undertook a cross-sectional, observational study of a sample of 142 eyes from Spanish diabetic patients suspected of having DRDME in 2012–2013. Our outcome was DRDME and the secondary variables were: type of diabetes, gender, age, glycated hemoglobin (HbA1c), foveal thickness and visual acuity (best corrected). The sample was divided into two parts: 80% to construct the tool and 20% to validate it. A binary logistic regression model was used to predict DRDME. The resulting model was transformed into a scoring system. The area under the ROC curve (AUC) was calculated and risk groups established. The tool was validated by calculating the AUC and comparing expected events with observed events. The construction sample (n = 106) had 35 DRDME (95% CI [24.1–42.0]), and the validation sample (n = 36) had 12 DRDME (95% CI [17.9–48.7]). Factors associated with DRDME were: HbA1c (per 1%) (OR = 1.36, 95% CI [0.93–1.98], p = 0.113), foveal thickness (per 1 μm) (OR = 1.03, 95% CI [1.01–1.04], p < 0.001) and visual acuity (per unit) (OR = 0.14, 95% CI [0.00–0.16], p < 0.001). AUC for the validation: 0.90 (95% CI [0.75–1.00], p < 0.001). No significant differences were found between the expected and the observed outcomes (p = 0.422). In conclusion, we constructed and validated a simple rapid tool to determine whether a diabetic patient suspected of having DRDME really has it. This tool has been implemented on a mobile app. Further validation studies are required in the general diabetic population.
关键词： Diabetes mellitus,Macular edema,Diagnostic tests,Statistical models,Diabetic retinopathy,Optical coherence tomography
更新于2025-09-19 17:15:36
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[IEEE 2019 14th IEEE Conference on Industrial Electronics and Applications (ICIEA) - Xi'an, China (2019.6.19-2019.6.21)] 2019 14th IEEE Conference on Industrial Electronics and Applications (ICIEA) - Photovoltaic consumption in distribution network considering shiftable load
摘要： In this paper, a joint feature selection and parameter estimation algorithm is presented for hidden Markov models (HMMs) and hidden semi-Markov models (HSMMs). New parameters, feature saliencies, are introduced to the model and used to select features that distinguish between states. The feature saliencies represent the probability that a feature is relevant by distinguishing between state-dependent and state-independent distributions. An expectation maximization algorithm is used to calculate maximum a posteriori estimates for model parameters. An exponential prior on the feature saliencies is compared with a beta prior. These priors can be used to include cost in the model estimation and feature selection process. This algorithm is tested against maximum likelihood estimates and a variational Bayesian method. For the HMM, four formulations are compared on a synthetic data set generated by models with known parameters, a tool wear data set, and data collected during a painting process. For the HSMM, two formulations, maximum likelihood and maximum a posteriori, are tested on the latter two data sets, demonstrating that the feature saliency method of feature selection can be extended to semi-Markov processes. The literature on feature selection speci?cally for HMMs is sparse, and non-existent for HSMMs. This paper ?lls a gap in the literature concerning simultaneous feature selection and parameter estimation for HMMs using the EM algorithm, and introduces the notion of selecting features with respect to cost for HMMs.
关键词： maximum a posteriori estimation.,hidden Markov models,hidden semi-Markov models,Feature selection
更新于2025-09-19 17:13:59
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The Impact of Surface Processes on the Ja??V Characteristics of Organic Solar Cells
摘要： Recent advances in energy storage devices (ESDs) technology have enabled new guidance strategies for power generation and distribution on hybrid marine power plants, supported by new class regulations. In this paper, a new model to calculate the fuel saving and emission reduction potential is derived based on the ESD maximum charge/discharge rate, engine efficiency, and specific fuel oil consumption (SFOC) curve. Several cases were analyzed with generator disconnection and also without it. Spline approximation for the discrete fuel oil consumption curve is used for numerical solution and later optimized using the Karush–Kuhn–Tucker method. A second approach is proposed, using linear interpolation, reducing the optimization process computational time. It is shown that fuel savings can be increased and emissions reduced by charging and discharging the energy storage device. This is denoted as strategic loading according to the proposed model. The cases with highest potential for fuel saving are shown to be cases where generators are disconnected.
关键词： smart grids,energy storage,optimization,fuel economy,numerical models,analytical models,Hybrid power systems
更新于2025-09-19 17:13:59
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Up-Conversion Device Based on Quantum Dots With High-Conversion Efficiency Over 6%
摘要： Recent advances in energy storage devices (ESDs) technology have enabled new guidance strategies for power generation and distribution on hybrid marine power plants, supported by new class regulations. In this paper, a new model to calculate the fuel saving and emission reduction potential is derived based on the ESD maximum charge/discharge rate, engine efficiency, and specific fuel oil consumption (SFOC) curve. Several cases were analyzed with generator disconnection and also without it. Spline approximation for the discrete fuel oil consumption curve is used for numerical solution and later optimized using the Karush–Kuhn–Tucker method. A second approach is proposed, using linear interpolation, reducing the optimization process computational time. It is shown that fuel savings can be increased and emissions reduced by charging and discharging the energy storage device. This is denoted as strategic loading according to the proposed model. The cases with highest potential for fuel saving are shown to be cases where generators are disconnected.
关键词： smart grids,analytical models,numerical models,optimization,energy storage,fuel economy,Hybrid power systems
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Performance Loss Rate Consistency and Uncertainty Across Multiple Methods and Filtering Criteria
摘要： In this paper, a joint feature selection and parameter estimation algorithm is presented for hidden Markov models (HMMs) and hidden semi-Markov models (HSMMs). New parameters, feature saliencies, are introduced to the model and used to select features that distinguish between states. The feature saliencies represent the probability that a feature is relevant by distinguishing between state-dependent and state-independent distributions. An expectation maximization algorithm is used to calculate maximum a posteriori estimates for model parameters. An exponential prior on the feature saliencies is compared with a beta prior. These priors can be used to include cost in the model estimation and feature selection process. This algorithm is tested against maximum likelihood estimates and a variational Bayesian method. For the HMM, four formulations are compared on a synthetic data set generated by models with known parameters, a tool wear data set, and data collected during a painting process. For the HSMM, two formulations, maximum likelihood and maximum a posteriori, are tested on the latter two data sets, demonstrating that the feature saliency method of feature selection can be extended to semi-Markov processes. The literature on feature selection speci?cally for HMMs is sparse, and non-existent for HSMMs. This paper ?lls a gap in the literature concerning simultaneous feature selection and parameter estimation for HMMs using the EM algorithm, and introduces the notion of selecting features with respect to cost for HMMs.
关键词： hidden Markov models,maximum a posteriori estimation,hidden semi-Markov models,Feature selection
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Spatio-Temporal Downscaling of Hourly Solar Irradiance Data Using Gaussian Copulas
摘要： Recent advances in energy storage devices (ESDs) technology have enabled new guidance strategies for power generation and distribution on hybrid marine power plants, supported by new class regulations. In this paper, a new model to calculate the fuel saving and emission reduction potential is derived based on the ESD maximum charge/discharge rate, engine efficiency, and specific fuel oil consumption (SFOC) curve. Several cases were analyzed with generator disconnection and also without it. Spline approximation for the discrete fuel oil consumption curve is used for numerical solution and later optimized using the Karush–Kuhn–Tucker method. A second approach is proposed, using linear interpolation, reducing the optimization process computational time. It is shown that fuel savings can be increased and emissions reduced by charging and discharging the energy storage device. This is denoted as strategic loading according to the proposed model. The cases with highest potential for fuel saving are shown to be cases where generators are disconnected.
关键词： smart grids,energy storage,optimization,fuel economy,numerical models,analytical models,Hybrid power systems
更新于2025-09-19 17:13:59