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Exploring anharmonic lattice dynamics and dielectric relations in niobate perovskites from first-principles self-consistent phonon calculations

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npj Computational Materials 2023年第1期9卷 757-766页

作者： Kwangrae Kim Woohyun Hwang Seung-Hyun victor Oh Aloysius Soon Department of Materials Science&Engineering Yonsei UniversitySeoul 03722Republic of Korea

Group I niobates(KNbO_(3) and NaNbO_(3))are promising lead-free alternatives for high-performance energy storage *** their potential,their complex phase transitions arising from temperature-dependent phonon softening and anharmonic effects on dielectric properties remain poorly *** this study,we employ density-functional theory(DFT)and self-consistent phonon(SCP)calculations to investigate finite-temperature phonons in cubic niobate *** include explicit anharmonic vibrational effects,SCP frequencies are shifted by the bubble self-energy correction within the quasiparticle(QP)approximation,providing precise descriptions of phonon softening in these strongly anharmonic *** further calculate the static dielectric constant of KNbO_(3) and NaNbO_(3) as a function of temperature using the Lyddane-Sachs-Teller(LST)relation and QP-corrected phonon *** theoretical results align with experimental data,offering reliable temperature-dependent phonon dispersions while considering anharmonic self-energies and thermal expansion effects,enhancing our understanding of the complex relations between lattice vibrations and phase transitions in these anharmonic oxides.

关键词： harmonic phonon dielectric

On the Conversion of High-Frequency Soliton Solutions to a （1＋1）-Dimensional Nonlinear Partial Differential Evolution Equation

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Chinese Physics Letters 2008年第6期25卷 1972-1975页

作者： Kuetche Kamgang victor Bouetou Bouetou Thomas Timoleon Crepin Kofane Department of Physics Faculty of Science University of Yaounde Ⅰ PO Box 812 Cameroon Ecole Nationale Supérieure Polytechnique University of Yaounde Ⅰ PO Box 8390 Cameroon The Abdus Salam International Centre for Theoretical Physics PO Box 586 Strada Costiera Ⅱ-34014 Trieste Italy

From the dynamical equation of barotropic relaxing media beneath pressure perturbations, and using the reductive perturbative analysis, we investigate the soliton structure of a （1＋1）-dimensional nonlinear partial differential evolution （NLPDE） equation δy（δη ＋ uδy ＋（u^2/2）δy）u ＋ auy ＋ u = 0, describing high-frequency regime of perturbations. Thus, by means of Hirota＇s bilinearization method, three typical solutions depending strongly upon a characteristic dissipation parameter are unearthed.

关键词： supernova explosion proto-neutron star shock wave

Using deep neural networks coupled with principal component analysis for ore production forecasting at open-pit mines

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第3期16卷 727-740页

作者： Chengkai Fan Na Zhang Bei Jiang Wei victor Liu Department of Civil and Environmental Engineering University of AlbertaEdmontonAlbertaT6G 2E3Canada Department of Mathematical and Statistical Sciences University of AlbertaEdmontonAlbertaT6G 2G1Canada

Ore production is usually affected by multiple influencing inputs at open-pit ***,the complex nonlinear relationships between these inputs and ore production remain *** becomes even more challenging when training data(*** haulage information and weather conditions)are *** machine learning(ML)algorithms,deep neural network(DNN)is a superior method for processing nonlinear and massive data by adjusting the amount of neurons and hidden *** study adopted DNN to forecast ore production using truck haulage information and weather conditions at open-pit mines as training *** the prediction models were built,principal component analysis(PCA)was employed to reduce the data dimensionality and eliminate the multicollinearity among highly correlated input *** verify the superiority of DNN,three ANNs containing only one hidden layer and six traditional ML models were established as benchmark *** DNN model with multiple hidden layers performed better than the ANN models with a single hidden *** DNN model outperformed the extensively applied benchmark models in predicting ore *** can provide engineers and researchers with an accurate method to forecast ore production,which helps make sound budgetary decisions and mine planning at open-pit mines.

关键词： Oil sands production Open-pit mining Deep learning Principal component analysis(PCA) Artificial neural network Mining engineering

Machine learning methods for rockburst prediction-state-of-the-art review

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International Journal of Mining Science and Technology 2019年第4期29卷 565-570页

作者： Yuanyuan Pu Derek B.Apel victor Liu Hani Mitri School of Mining and Petroleum Engineering University of AlbertaEdmonton T6G 2R3Canada Department of Mining and Materials Engineering McGill UniversityMontreal H3A 2T6Canada

One of the most serious mining disasters in underground mines is rockburst *** can lead to injuries and even fatalities as well as damage to underground openings and mining *** has forced many researchers to investigate alternative methods to predict the potential for rockburst ***,due to the highly complex relation between geological,mechanical and geometric parameters of the mining environment,the traditional mechanics-based prediction methods do not always yield precise *** the emergence of machine learning methods,a breakthrough in the prediction of rockburst occurrence has become possible in recent *** paper presents a state-ofthe-art review of various applications of machine learning methods for the prediction of rockburst ***,existing rockburst prediction methods are introduced,and the limitations of such methods are highlighted.A brief overview of typical machine learning methods and their main features as predictive tools is then *** current applications of machine learning models in rockburst prediction are surveyed,with related mechanisms,technical details and performance analysis.

关键词： Rockburst prediction Burst liability Artificial neural network Support vector machine Deep learning

Day-ahead industrial load forecasting for electric RTG cranes

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Journal of Modern Power Systems and Clean Energy 2018年第2期6卷 223-234页

作者： Feras ALASALI Stephen HABEN victor BECERRA William HOLDERBAUM School of Systems Engineering University of Reading Mathematical Institute University of Oxford School of Engineering University of Portsmouth School of Engineering Metropolitan Manchester University

Given the increase in international trading and the significant energy and environmental challenges in ports around the world, there is a need for a greater understanding of the energy demand behaviour at *** move towards electrified rubber-tyred gantry(RTG)cranes is expected to reduce gas emissions and increase energy savings compared to diesel RTG cranes but it will increase electrical energy demand. Electrical load forecasting is a key tool for understanding the energy demand which is usually applied to data with strong regularities and seasonal patterns. However, the highly volatile and stochastic behaviour of the RTG crane demand creates a substantial prediction challenge. This paper is one of the first extensive investigations into short term load forecastsfor electrified RTG crane demand. Options for model inputs are investigated depending on extensive data and correlation analysis. The effect of estimation accuracy of exogenous variables on the forecast accuracy is investigated as well. The models are tested on two different RTG crane data sets that were collected from the Port of Felixstowe in the UK. The results reveal the effectiveness of the forecast models when the estimation of the number of crane moves and container gross weight are accurate.

关键词： Rubber-tyred gantry(RTG) cranes Correlation analysis Exogenous variables estimation Artificial neural networks Time series forecast modelling

Reduction of NO by CO using Pd–CeTb and Pd–CeZr catalysts supported on SiO_2 and La_2O_3–Al_2O_3

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Journal of Environmental Sciences 2015年第1期27卷 87-96页

作者： victor Ferrer Dora Finol Roger Solano Alexander Moronta Miguel Ramos Instituto de Superficies y Catálisis Facultad de Ingeniería Universidad del Zulia Instituto Zuliano de Investigaciones Tecnológicas km 15 carretera Vía a la Ca?ada Apartado 331 Venezuela

The catalytic activity of Pd catalysts supported on Ce0.73Tb0.27Ox/SiO2, Ce0.6Zr0.4Ox/Si O2,Ce0.73Tb0.27Ox/La2O3–Al2O3and Ce0.6Zr0.4Ox/La2O3–Al2O3was studied using the reduction of NO by CO. The catalysts were characterized by X-ray fluorescence, surface area, X-ray diffraction, temperature-programmed reduction, CO chemisorption and oxygen storage capacity. Temperature-programmed reduction results indicated that Tb or Zr incorporation improves the reducibility and oxygen storage capacity. CO chemisorption data suggested the presence of large Pd O particles due to the low CO/Pd ratio. No significant differences were obtained in light off temperatures（T Light off） for all Pd catalysts and the most active was1.5%Pd/Ce0.6Zr0.4Ox/SiO2.

关键词： Mixed oxides OSC Reduction of NO by CO Three way catalysts

A comparative study of geometric and geostatistical methods for qualitative reserve estimation of limestone deposit

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Geoscience Frontiers 2021年第1期12卷 243-253页

作者： Thomas Busuyi Afeni victor Oluwatosin Akeju Adeyemi Emman Aladejare Department of Mining Engineering Federal University of TechnologyAkureNigeria Oulu Mining School University of OuluOuluFinland

Mining projects especially relating to limestone deposits require an accurate knowledge of tonnage and grade,for both short and long-term *** is often difficult to establish as detailed exploration operations,which are required to get the accurate description of the deposit,are costly and time *** and mining engineers usually make use of geometric and geostatistical methods,for estimating the tonnage and grade of ore ***,explicit assessments into the differences between these methods have not been reported in *** bridge this research gap,a comparative study is carried out to compare the qualitative reserve of Oyo-Iwa limestone deposit located in Nigeria,using geometric and geostatistical *** geometric method computes the reserve of the limestone deposit as 74,536,820 t(mean calcite,CaO grade=52.15)and 99,674,793 t(mean calcite,CaO grade=52.32),for the Northern and Southern zones of the deposit,*** the other hand,the geostatistical method calculates the reserve as 81,626,729.65 t(mean calcite,CaO grade=53.36)and 100,098,697.46 t(mean calcite,CaO grade=52.96),for the two zones,*** small relative difference in tonnage estimation between the two methods(i.e.,9.51%and 0.43%),proves that the geometric method is effective for tonnage *** contrast,the relative difference in grade estimation between the two methods(i.e.,2.32%and 1.26%)is not negligible,and could be crucial in maintaining the profitability of the *** geostatistical method is,therefore,more suitable,reliable and preferable for grade estimation,since it involves the use of spatial modelling and cross-validated *** addition,the geostatistical method is used to produce quality maps and three-dimensional(3-D)perspective view of the limestone *** quality maps and 3-D view of the limestone deposit reveal the variability of the limestone grade within the deposit,and it is useful for operational ma

关键词： Geostatistics Geometric Triangular block Limestone Quality maps Ordinary kriging

Resilience by design:How nature,nurture,environment,and microbiome mitigate stress and allostatic load

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World Journal of Psychiatry 2023年第5期13卷 144-159页

作者： Souhad Chbeir victor Carrión Department of Psychiatry and Behavioral Sciences School of MedicineStanford UniversityStanfordCA 94305United States

Resilience to psychological stress is defined as adaption to challenging life experiences and not the absence of adverse life *** of resilience include personality traits,genetic/epigenetic modifications of genes involved in the stress response,cognitive and behavioral flexibility,secure attachment with a caregiver,social and community support systems,nutrition and exercise,and alignment of circadian rhythm to the natural light/dark ***,resilience is a dynamic and flexible process that continually evolves by the intersection of different domains in human’s life;biological,social,and *** objective of this minireview is to summarize the existing knowledge about the multitude factors and molecular alterations that result from resilience to stress *** the multiple contributing factors in building resilience,we set out a goal to identify which factors were most supportive of a causal role by the current *** focused on resilience-related molecular alterations resulting from mind-body homeostasis in connection with psychosocial and environmental *** conclude that there is no one causal factor that differentiates a resilient person from a vulnerable ***,building resilience requires an intricate network of positive experiences and a healthy lifestyle that contribute to a balanced mind-body ***,a holistic approach must be adopted in future research on stress response to address the multiple elements that promote resilience and prevent illnesses and psychopathology related to stress allostatic load.

关键词： stress load alignment

Formation of diffuse and spark discharges between two needle electrodes with the scattering of particles

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Plasma Science and Technology 2024年第9期26卷 32-39页

作者： victor F TARASENKO Dmitry V BELOPLOTOV Alexei N PANCHENKO Dmitry A SOROKIN Institute of High Current Electronics Siberian BranchRussian Academy of SciencesTomsk 634055Russia National Research Tomsk State University Tomsk 634050Russia

The development of a nanosecond discharge in a pin-to-pin gap filled with air at atmospheric pressure has been studied with high temporal and spatial resolutions from a breakdown start to the spark *** and negative nanosecond voltage pulses with an amplitude of tens of kilovolts were ***-resolved images of the discharge development were taken with a fourchannel Intensified Charge Coupled Device(ICCD)*** minimum delay between the camera channels could be as short as≈0.1 *** made it possible to study the gap breakdown process with subnanosecond *** was observed that a wide-diameter streamer develops from the high-voltage pointed *** ionization processes near the grounded pin electrode started when the streamer crossed half of the *** bridging the gap by the streamer,a diffuse discharge was *** development of spark leaders from bright spots on the surface of the pointed electrodes was observed at the next *** was found that the rate of development of the spark leader is an order of magnitude lower than that of the wide-diameter *** thin luminous tracks were observed against the background of a discharge plasma *** has been established that the tracks are adjacent to brightly glowing spots on the electrodes and are associated with the flight of small particles.

关键词： needle electrodes short voltage pulses atmospheric air streamer breakdown diffuse and spark discharges scattering metal particles