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- 摘要
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- 实验方案
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Production of a Scalar Boson and a Heavy Fermion Pair in Counterpropagating Е–Е+ Beams
摘要： The process of production of an HSM scalar boson of the Standard Model (H and h bosons of the Minimal Supersymmetric Standard Model) and a heavy fermion pair tt in counterpropagating electron-positron beams e+ e- -> H tt (e+ e- -> h tt) is discussed. Analytical expressions for the energy spectrum of the Higgs boson and the transverse spin asymmetry and the right-left spin asymmetry are obtained, and their dependences on the emission angle and energy of the Higgs boson are investigated.
关键词： left and right coupling constants,heavy fermion pair,Standard Model,Minimal Supersymmetric Standard Model,Weinberg parameter
更新于2025-09-23 15:23:52
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Prediction model optimization using full model selection with regression trees demonstrated with FTIR data from bovine milk
摘要： Predictive modeling is the development of a model that is best able to predict an outcome based on given input variables. Model algorithms are different processes that are used to define functions that transform the data within models. Common algorithms include logistic regression (LR), linear discriminant analysis (LDA), classification and regression trees (CART), na?ve Bayes (NB), and k-nearest neighbor (KNN). Data preprocessing option, such as feature extraction and reduction, and model algorithms are commonly selected empirically in epidemiological studies even though these decisions can significantly affect model performance. Accordingly, full model selection (FMS) methods were developed to provide a systematic approach to select predictive modeling methods; however, current limitations of FMS, such as its dependency on user-selected hyperparameters, have prevented their routine incorporation into analyses for model performance optimization. Here we present the use of regression trees as an innovative method to apply FMS. Regression tree FMS (rtFMS) requires the development of a model for every combination of predictive modeling method options under consideration. The iterated, cross-validation performances of these models are then passed through a regression tree for selection of a final model. We demonstrate the benefits of rtFMS using a milk Fourier transform infrared spectroscopy dataset, wherein we build prediction models for two blood metabolic health parameters in dairy cows, nonesterified fatty acids (NEFA) and β-hydroxybutyrate acid (BHBA). The goal for building NEFA and BHBA prediction models is to provide a milk-based screening tool for metabolic health in dairy cattle that can be incorporated automatically in milk analysis routines. These models could be used in conjunction with physical exams, cow side tests, and other indications to initiate medical intervention. In contrast to previously reported FMS methods, rtFMS is not a black box, is simple to implement and interpret, it does not have hyperparameters, and it illustrates the relative importance of modeling options. Additionally, rtFMS allows for indirect comparisons among models developed using different datasets. Finally, rtFMS eliminates user bias due to personal preference for certain methods and rtFMS removes the dependency on published comparisons of methods. Thus, rtFMS provides clear benefits over the empirical selection of data preprocessing options and model algorithms.
关键词： Prediction model,Fourier-transform infrared spectra,Regression tree,Preprocessing,Full model selection
更新于2025-09-23 15:23:52
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[IEEE 2018 15th International Multi-Conference on Systems, Signals & Devices (SSD) - Yassmine Hammamet, Tunisia (2018.3.19-2018.3.22)] 2018 15th International Multi-Conference on Systems, Signals & Devices (SSD) - An Integrated Thermal and Electrical Model for PV Panel Performance
摘要： This work presents an integrated thermal and electrical model for Photovoltaic panel based on Matlab/Simulink tools. The model is designed for extreme and dusty weather conditions. The objective of this work is to reach a realistic online simulation that accommodates all major environmental variables such ambient temperature, relative humidity, wind speed and solar irradiation. The water mass flow rate was used to control the PV panel temperature through surface cooling in order to boost its output power. The output power adjustment was needed for power system operation purposes. The developed model is now ready any future controller development. The obtained results for testing the model under varying online climatic conditions and for various water mass flow rates were very satisfactory. The use of water to cool the panel played two major roles namely PV cleaning and temperature reduction then consequently increasing the panel power output.
关键词： Thermal model,Simulation,surface cooling,PV panel performance,Electrical model
更新于2025-09-23 15:23:52
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[IEEE 2018 28th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV) - Greifswald (2018.9.23-2018.9.28)] 2018 28th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV) - Simulation of the Interaction between High Current Vacuum Arc and Macroparticles in Small-Size Trigatron
摘要： This work investigates the interaction between high current vacuum arc (HCVA) and the macroparticle (MP) generated from the cathode spots (CS) in the small-size vacuum trigatron. Magnetohydrodynamic (MHD) model is used to describe the arc column. MPs are added into MHD model, which are described by discrete phase model (DPM). The control equations of MPs include charging equation, motion equation and heat transfer equation, in which the evaporation of MPs is also considered. Based on the above model, the effects of MP diameter and arc current on the characteristics of MPs are studied. Simulation results show that MPs leave the interelectrode gap with a deflection angle larger than the initial angle under the influence of plasma. The motion of MPs is similar to that of projectiles. MPs with smaller diameter are influenced by the arc plasma more significantly. MPs can act as a source of the plasma, but these influences are not obvious in HCVA. What may be more harmful to the trigatron is the charging process of MPs during post-arc process.
关键词： magnetohydrodynamic model,macroparticle,discrete phase model,vacuum arc
更新于2025-09-23 15:23:52
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A Geographically and Temporally Weighted Regression Model for Ground-Level PM2.5 Estimation from Satellite-Derived 500 m Resolution AOD
摘要： Regional haze episodes have occurred frequently in eastern China over the past decades. As a critical indicator to evaluate air quality, the mass concentration of ambient fine particulate matters smaller than 2.5 μm in aerodynamic diameter (PM2.5) is involved in many studies. To overcome the limitations of ground measurements on PM2.5 concentration, which is featured in disperse representation and coarse coverage, many statistical models were developed to depict the relationship between ground-level PM2.5 and satellite-derived aerosol optical depth (AOD). However, the current satellite-derived AOD products and statistical models on PM2.5–AOD are insufficient to investigate PM2.5 characteristics at the urban scale, in that spatial resolution is crucial to identify the relationship between PM2.5 and anthropogenic activities. This paper presents a geographically and temporally weighted regression (GTWR) model to generate ground-level PM2.5 concentrations from satellite-derived 500 m AOD. The GTWR model incorporates the SARA (simplified high resolution MODIS aerosol retrieval algorithm) AOD product with meteorological variables, including planetary boundary layer height (PBLH), relative humidity (RH), wind speed (WS), and temperature (TEMP) extracted from WRF (weather research and forecasting) assimilation to depict the spatio-temporal dynamics in the PM2.5–AOD relationship. The estimated ground-level PM2.5 concentration has 500 m resolution at the MODIS satellite's overpass moments twice a day, which can be used for air quality monitoring and haze tracking at the urban and regional scale. To test the performance of the GTWR model, a case study was carried out in a region covering the adjacent parts of Jiangsu, Shandong, Henan, and Anhui provinces in central China. A cross validation was done to evaluate the performance of the GTWR model. Compared with OLS, GWR, and TWR models, the GTWR model obtained the highest value of coefficient of determination (R2) and the lowest values of mean absolute difference (MAD), root mean square error (RMSE), and mean absolute percentage error (MAPE).
关键词： GTWR model,SARA AOD,hourly ground-level PM2.5 concentration,500 m resolution,MODIS,AERONET
更新于2025-09-23 15:23:52
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Utilization of Multiphoton Imaging For Real-Time Fate Determination of Mesenchymal Stem Cells in an Immunocompetent Mouse Model
摘要： The clinical application of Mesenchymal Stem Cells (MSCs) for the treatment of a variety of diseases is the focus of intense research. Despite large research efforts many questions regarding MSC biology in vivo remain unanswered. For instance, we do not know for certain whether MSCs exert their therapeutic effects directly within the target tissue or indirectly by influencing the polarization of other cell types, such as macrophages, which can then home to the target tissue microenvironment. To help address this issue, the application of intravital multiphoton microscopy allows for the determination of the dynamic action of intact MSCs versus endogenous host cells at the target tissue site in real time.
关键词： Mesenchymal Stem Cell,Granulocyte,MSC,Intravital,Mouse Model,Multiphoton
更新于2025-09-23 15:23:52
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Sky camera geometric calibration using solar observations
摘要： A camera model and associated automated calibration procedure for stationary daytime sky imaging cameras is presented. The specific modeling and calibration needs are motivated by remotely deployed cameras used to forecast solar power production where cameras point skyward and use 180° fisheye lenses. Sun position in the sky and on the image plane provides a simple and automated approach to calibration; special equipment or calibration patterns are not required. Sun position in the sky is modeled using a solar position algorithm (requiring latitude, longitude, altitude and time as inputs). Sun position on the image plane is detected using a simple image processing algorithm. The performance evaluation focuses on the calibration of a camera employing a fisheye lens with an equisolid angle projection, but the camera model is general enough to treat most fixed focal length, central, dioptric camera systems with a photo objective lens. Calibration errors scale with the noise level of the sun position measurement in the image plane, but the calibration is robust across a large range of noise in the sun position. Calibration performance on clear days ranged from 0.94 to 1.24 pixels root mean square error.
关键词： fisheye lens,geometric calibration,camera model,sky camera,solar observations,solar power forecasting
更新于2025-09-23 15:23:52
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Maximizing the Current Output in Self-Aligned Graphene–InAs–Metal Vertical Transistors
摘要： With finite density of states and electrostatically tunable work function, graphene can function as a tunable contact for semiconductor channel to enable vertical field effect transistors (VFET). However, the overall performance, especially the output current density is still limited by the low conductance of the vertical semiconductor channel, as well as large series resistance of graphene electrode. To overcome these limitations, we construct a VFET by using single crystal InAs film as the high conductance vertical channel and self-aligned metal contact as the source-drain electrodes, resulting a record high current density over 45,000 A/cm2 at a low bias voltage of 1 V. Furthermore, we construct a device-level VFET model using resistor network method, and experimentally validate the impact of each geometry parameter on device performance. Importantly, we found the device performance is not only a function of intrinsic channel material, but also greatly influenced by device geometries and footprint. Our study not only pushes the performance limit of graphene VFETs, but also sheds light on van der Waals integration between two-dimensional material and conventional bulk material for high performance VFETs and circuits.
关键词： resistor network model,high current density,vertical transistor,graphene,van der Waals heterostructure,InAs film
更新于2025-09-23 15:23:52
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Quantumness in light harvesting is determined by vibrational dynamics
摘要： We demonstrate for the multi-level spin-boson (MLSB) Hamiltonian, typically used to describe biological light-harvesting, that the distinction between quantum and classical dynamics is determined entirely by the thermal environment. In particular, any MLSB model featuring classical interactions with a classical bath is exactly equivalent in its absorption and energy transfer dynamics to a classical model involving coupled harmonic oscillators. This result holds in the linear response regime for both pulsed and incoherent excitation. In the biological context, this finding highlights the centrality of vibrational dynamics in determining the 'quantumness' of photosynthetic light-harvesting, particularly in the creation of the photosynthetic energy funnel where excitation energy concentrates near the reaction center via a series of downhill energy transfer events. These findings support the idea that this energy funnel is exclusively quantum-mechanical in origin, although it need not rely on entanglement.
关键词： vibrational dynamics,energy transfer,photosynthesis,quantumness,light harvesting,spin-boson model
更新于2025-09-23 15:23:52
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[ACM Press the 3rd International Conference - Tetouan, Morocco (2018.10.10-2018.10.11)] Proceedings of the 3rd International Conference on Smart City Applications - SCA '18 - Empirical models for estimating the global solar radiation based on air temperature and sunshine duration
摘要： This work aims to develop and validate empirical models for estimating global solar radiation at site of Alhoceima based on the meteorological data measured during the period 2010-2017. The empirical models studied in this paper are broken down into two categories: the first category consist of linear and nonlinear regression which relates the monthly average daily global solar radiation to the sunshine duration, such as: the model of Angstr?m-Prescott, the cubic, quadratic model (Ogleman et al.), exponential (Almorox), logarithmic and power model. The second category consists of mathematical models calculating the monthly average daily global solar radiation based on the air temperature. And finally this study proposed model wish is based on sunshine duration and gives the best results for the city of Alhoceima. Statistical evaluation of the performance and accuracy of the models on the basis of The Root Mean Square Error (RMSE), Mean Bias Error MBE and R2 coefficient of determination, showed that all calibrated models estimates very well the monthly average daily global radiation. However the proposed model is more accurate with smaller errors and the best coefficient of determination.
关键词： air temperature,empirical model,sunshine duration,Daily global solar radiation,estimating global solar radiation
更新于2025-09-23 15:23:52