jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Alessandro Inglese
Source: Aaltodoc (Aalto University) (article, 2018-01-01)
Field: Materials Science — Surfaces, Coatings and Films

On the light-activation of copper impurities in crystalline silicon: root cause analysis and applications for fast high-resolution imaging In silicon-based devices copper (Cu) contamination is the cause of a variety of adverse effects, one of them being the so-called light-induced degradation (Cu-LID). This phenomenon results in the progressive reduction of minority carrier lifetime during light-soaking, thus becoming a particular issue in devices sensitive to this parameter, such as state-of-the-art silicon solar cells. The content of this dissertation elucidates various aspects of Cu-LID that have long remained unclear and examines the possibility of leveraging this knowledge to quantitatively detect copper impurities from carrier lifetime measurements. &#13;\n&#13;\nFirst, experiments carried out on specimens featuring lightly doped phosphorus emitters provide insights into the effect of gettering on the strength of Cu-LID. It is found that in specimens with a phosphorus-diffused emitter significant suppression of Cu-LID is achievable through the addition of a slow cooling tail after high-temperature anneals. On the other hand, in another batch of differently processed specimens none of the tested gettering schemes results in the suppression of Cu-LID. Further investigations into this latter set of specimens indicate oxygen precipitation as the cause for the ineffectiveness of the gettering treatments. &#13;\n&#13;\nThe fact that relevant quantities of Cu may persist in the bulk region after phosphorus gettering treatments raises the need for deeper understanding into the mechanisms causing Cu-LID and development of fast and contactless methods for quickly detecting copper impurities in silicon substrates. In this dissertation, multiple evidence towards bulk Cu precipitation being the root-cause of Cu-LID is provided via (i) defect characterization based on the Shockley-Read-Hall theory, (ii) analysis of the experimental data in terms of a Schottky recombination model that specifically describes the effect of metallic precipitates on the carrier lifetime, (iii) modelling of the light-induced precipitation process and comparison of the simulation results with the existing experimental data. These ﬁndings also constitute the theoretical framework for the formulation of an imaging method that provides quantitative and spatially-resolved information on the distribution of Cu species across the silicon wafer. Such method relies on the acceleration of the degradation process through simultaneous illumination and low-temperature annealing and subsequent comparison of lifetime data with the values predicted by the aforementioned Schottky model. Examples of application of this approach to deliberately contaminated mono- and multicrystalline specimens are also discussed. Copper ; Impurity ; Silicon ; Materials science ; Metallurgy ; Chemistry Electron and X-Ray Spectroscopy Techniques ; Silicon and Solar Cell Technologies
Authors: Andrew Smith | L'Imperio | Mariafrancesca Mazza | Elena Ajello | Fabio Pagni | Fulvio Magni
Source: BOA (University of Milano-Bicocca) (article, 2018-01-01)
Field: Chemistry — Spectroscopy

MALDI-MS imaging in the search for proteomic indicators of response to therapy in membranous nephropathy Membranous Nephropathy (MN) is the most frequent cause of nephrotic syndrome in adults and the disease course is characterised by the “rule of third”, with one third of patients experiencing complete remission and the remaining experiencing relapses or progression of the disease. Additionally, the therapeutic approach is not standardised, leading to further heterogeneity in terms of response and outcome. In this pilot study, MALDI-MSI analysis was performed on renal biopsies obtained from two groups of patients, selected from 120 subjects with MN, which differentially responded to the range of immunosuppressive treatments administered. All the mass spectra were acquired in reflectron positive mode in the mass range of m/z 750 to 3500 using a rapifleX MALDI TissuetyperTM with a pixel width and raster setting of 10μm, respectively. Three signals were determined to have a statistical significance when comparing the two patient groups (m/z 1111, 1198 and 1303) and had an altered signal intensity within glomeruli and tubular regions. Furthermore, the results highlighted the benefit of performing high spatial resolution MALD-MSI in the search prognostic markers of this frequent glomerulopathy. In particular, the signals that correlated with the response of the patient to the therapy could be spatially resolved within the different glomerular sub-structures and this localisation had a significant impact on the prognostic outlook of the patient. Despite much effort being made in recent years to understand the pathogenesis of MN, a panel of biomarkers able to predict the outcome of these patients following therapeutic treatment is still lacking. Here, we highlight a prospective panel of markers that can differentiate between these MN patients and could be a valuable starting point for a further study focused on verifying their predictive role in the treatment of Membranous Nephropathy Membranous nephropathy ; Medicine ; Computational biology ; Internal medicine ; Glomerulonephritis ; Biology ; Kidney Advanced Proteomics Techniques and Applications
Authors: Cuiling Zhang | Yi Ning | Shi Ya-he
Source: Proceedings of the 2018 International Conference on Mathematics, Modelling, Simulation and Algorithms (MMSA 2018) (article, 2018-01-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Review of Comprehensive Assessment of Power Transformer Since the power transformer is an important kind of electric power equipment in power system, in this paper, comprehensive evaluation of power transformer are divided into three parts: power transformer operation status, fault diagnosis and repair strategies. Furthermore, the evaluation methods of comprehensive evaluation analysis are proposed, which means, on-line monitoring, the method of fault diagnosis and condition-based maintenance strategy decision-making method. Summarizing the research thought, the application conditions and the research progress of these methods. Finally, some open problems for comprehensive evaluation of power transformer in this area are introduced. Transformer ; Computer science ; Reliability engineering ; Electrical engineering ; Engineering ; Voltage Magnetic Properties and Applications ; Geoscience and Mining Technology ; Advanced Decision-Making Techniques
Authors: Emil Johansson
Source: Lund University Publications Student Papers (Lund University) (article, 2018-01-01)
Field: Materials Science — Materials Chemistry

Teaching a Neural Network Quantum Mechanics. A Deep Learning Approach to the N-Representability Problem. We show that an unsupervised artificial neural network can be trained to parameterize the set of N representable density matrices well enough to enable ground state energy calculations. A one-dimensional harmonic oscillator system is used to test the method. 4, 5, or 6 fermions are placed in an external potential. They interact with one of three different interaction types. By choosing the most successful network according to a well-defined measure, the approach is shown to generalize to interaction types not considered by the measure. Measure (data warehouse) ; Artificial neural network ; Harmonic oscillator ; Set (abstract data type) ; Artificial intelligence ; Ground state ; Unsupervised learning ; Computer science ; Energy (signal processing) ; Statistical physics ; Mathematics ; Quantum mechanics ; Physics ; Data mining Machine Learning in Materials Science ; Neural Networks and Applications ; Topic Modeling
Authors: Mykhailo Vorobiov
Source: VCU Scholars Compass (Virginia Commonwealth University) (article, 2018-01-01)
Field: Chemistry — Organic Chemistry

PHOTOLUMINESCENCE FROM GAN CO-DOPED WITH C AND SI This thesis devoted to the experimental studies of yellow and blue luminescence (YL and BL relatively) bands in Gallium Nitride samples doped with C and Si. The band BLC was at first observed in the steady-state photoluminescence spectrum under high excitation intensities and discerned from BL1 and BL2 bands appearing in the same region of the spectrum. Using the time-resolved photoluminescence spectrum, we were able to determine the shape of the BLC and its position at 2.87 eV. Internal quantum efficiency of the YL band was estimated to be 90\\%. The hole capture coefficient of the BLC related state was determined as 7 10-10 cm3/s. Properties of BLC were investigated. The YL and BLC bands are attributed to electron transitions via the (0/-) and (+/0) transition levels of the CN defect. Photoluminescence ; Doping ; Materials science ; Optoelectronics ; Engineering physics ; Physics Synthesis and Biological Evaluation
Authors: Maryam Mudasir | Riaz Ahmed
Source: Key engineering materials (article, 2018-09-05)
Field: Materials Science — Polymers and Plastics

Investigations of Non-Linear Viscoelastic Properties for Polypropylene/Clay-Nanocomposites through Melt Flow Birefringence and Damping Function Rheological investigations are reported for pure polypropylene and its clay-nanocomposites to establish viscoelastic properties and filler concentration relationship. Flow birefringence is performed through a slit-die to obtain centerline principal stress difference during extensional flow. The centerline stress profile of clay-nanocomposite revealed additional viscoelastic nature even at low silicate concentrations whereas no exceptional strain hardening was reported. Effects of higher filler concentrations are further examined during the simple shearing flow to consider non-linear viscoelasticity in terms of damping function. The increase in damping coefficient with increasing clay concentration shows polymer-nanocomposites are more strain sensitive. The Wagner's exponential damping function could adequately describe the time-strain separability at all clay concentrations studied. The results of both investigations reveal that the polymers are time-strain separable at all clay concentrations studied during elongational and simple shearing flows, whereas filler orientations are found to be different for different melt flow behavior. Viscoelasticity ; Materials science ; Composite material ; Shearing (physics) ; Rheology ; Polypropylene ; Flow birefringence ; Polymer clay ; Strain hardening exponent ; Nanocomposite ; Polymer Polymer Nanocomposites and Properties ; Rheology and Fluid Dynamics Studies ; Polymer crystallization and properties
Authors: Yumei Hu | W. J. Meng | Tianqi Zheng | Chenju Zhang | Qianqian Yang | Zhengyu Zhu
Source: Materiali in tehnologije (article, 2018-03-25)
Field: Materials Science — Biomaterials

Deformation behavior of the Mg-7Zn-3Cu-1Ce alloy during hot compression The flow stress behavior of the Mg-7Zn-3Cu-1Ce alloy was studied on a Gleeble-1500 thermal/mechanical simulation test machine under the maximum deformation degree of 50 %, at a strain rate of 0.01 s -1 to 10 s -1 , and temperature of 573 to 673 K. The hot deformation behavior of the tested alloy during the hot compression process was studied. The experimental results showed that the correlation of the flow stress, strain rate and temperature was obvious and the tested alloy was a strain-ratesensitive material. The deformation activation energy (Q = 191 kJ/mol) and the corresponding stress exponent (n = 5.68) were evaluated by linear regression analysis during the hot deformation process. And the flow stress constitutive equation of the Mg-7Zn-3Cu-1Ce alloy was built by introducing the Zener-Hollomon parameter. There was no recrystallization phenomenon in the microstructure of the tested alloy after hot-compression, and dynamic recovery is the main softening mechanism during the high-temperature deformation. The extruded alloy (extrusion at 673 K) shows excellent mechanical properties both at room and at mid-high temperature. Materials science ; Compression (physics) ; Deformation (meteorology) ; Alloy ; Metallurgy ; Composite material Magnesium Alloys: Properties and Applications ; Aluminum Alloys Composites Properties ; Aluminum Alloy Microstructure Properties
Authors: Paul N. Patrone | Anthony J. Kearsley | Andrew Dienstfrey
Source:  (preprint, 2018-01-07)
Field: Materials Science — Materials Chemistry

The role of data analysis in uncertainty quantification: case studies for materials modeling In computational materials science, mechanical properties are typically extracted from simulations by means of analysis routines that seek to mimic their experimental counterparts. However, simulated data often exhibit uncertainties that can propagate into final predictions in unexpected ways. Thus, modelers require data analysis tools that (i) address the problems posed by simulated data, and (ii) facilitate uncertainty quantification. In this manuscript, we discuss three case studies in materials modeling where careful data analysis can be leveraged to address specific instances of these issues. As a unifying theme, we highlight the idea that attention to physical and mathematical constraints surrounding the generation of computational data can significantly enhance its analysis. Computer science ; Data science ; Theme (computing) ; Uncertainty quantification ; Data analysis ; Experimental data ; Computational model ; Data mining ; Artificial intelligence ; Machine learning ; Mathematics Machine Learning in Materials Science ; Composite Material Mechanics ; Polymer crystallization and properties
Authors: John Montano
Source: CSUSB ScholarWorks (California State University, San Bernardino) (article, 2018-05-17)
Field: Materials Science — Materials Chemistry

A New Paramagnetic & Piezoelectric Organometallic Material We have synthesized a new organometallic material that is predicted to be multiferroic. Ferroelectric materials can pave a way to exciting new technologies, such as FRAM. Bis(Diisopropylamonium) Cobalt(II) Tetrachloride, BLUE, is grown from beaker solutions containing; molar solution Cobalt(II) Chloride Hexahydrate(237.93g/L), Hydrochloric Acid (HCL), and 48 5th Annual Student Research Symposium Diisopropylamine (DIPA). Its density is 1.309 g/cm3 and melting point is above 130°C. Weak ferroelectric results are shown by Piezo Force Microscopy imaging a process of “reading and writing” domains onto ferroelectrics, while piezoelectric results are point tested with responses of 5-12 nA and qualitative hysteretic results. The Radiant System testing has shown butterfly curves that indicate piezoelectric responses for different samples of blue, and lemon shaped hysteresis curves due to resistance. Further testing is to be conducted on larger crystals and different axes with Atomic Force Microscopy and bulk capacitance testing. Piezoelectricity ; Ferroelectricity ; Hysteresis ; Atomic force microscopy ; Etching (microfabrication) ; Melting point ; Optical microscope ; Alloy Ferroelectric and Piezoelectric Materials ; Multiferroics and related materials ; Chemical and Physical Properties of Materials
Authors: Ryan Clark
Source: CSUSB ScholarWorks (California State University, San Bernardino) (article, 2018-01-01)
Field: Materials Science — Materials Chemistry

Environmental effects on single crystal growth in molten bismuth This project was developed to attempt to grow large bismuth crystals in a molten bismuth bath. After nearly a year of independent research I have been able to develop a procedure that results in large single and clustered crystal formations that when oxidized, 22 5th Annual Student Research Symposium exhibit an amazing rainbow refraction in the oxidization layer. This truly amazing element has many unusual properties and has many potential art applications. I will be attempting to identify the environmental forces such as vibration, ambient temperature, and other variables that control the cooling rate of liquid bismuth, which either hinder or promote single crystal growth during the solidification of molten bismuth. Once identified, these variables will be adjusted to encourage large single crystal growth. Bismuth ; Materials science ; Crystal growth ; Crystallography ; Chemistry ; Metallurgy Solidification and crystal growth phenomena ; Thermodynamic and Structural Properties of Metals and Alloys
Authors: Lili Xu | Jie Gu | Huazhou Chen | Jiangbei Wen | Gai-li Xu
Source: Open Journal of Applied Sciences (article, 2018-01-01)
Field: Chemistry — Analytical Chemistry

LSSVM Combined with SPA Applied to Near-Infrared Quantitative Determination of the Octane in Fuel Petrol Samples Least square support vector machine (LSSVM) combined with successive projection algorithm (SPA) method was applied for near-infrared (NIR) quantitative determination of the octane number in fuel petrol. The NIR spectra of 87 fuel petrol samples were scanned for model establishment and optimization. First order derivative Savitzky-Golay smoother (1st-d’SG) was utilized to improve the NIR predictive ability. Its pretreatment effect was compared with the raw data. SPA was applied for the extraction of informative wavelengths. Considering the linear and non-linear training mechanism, LSSVM regression was employed to establish calibration models. The correlation coefficient (R) and root mean square error (RMSE) were used as the model evaluation indices; accordingly the octane number in fuel petrol was quantitatively determined with the prospective predictive indices. Results showed that after pretreated by 1st-d’SG, 8 SPA-selected wavelengths was generated as the inputs of LSSVM, so that the calibration models were optimized in the way of combining the SPA-LSSVM regression with the SG smoother. The prediction results were quite satisfactory, with the calibrating correlation coefficient of 0.951 and the RMSE of 3.282. An independent testing sample set was used to evaluate the optimal model, the testing correlation coefficient was 0.903 and the RMSE was 4.128. We conclude that NIR spectrometry is feasible to determine the octane in fuel petrol by establishing SPA-LSSVM models. The 1st-d’SG pretreatment has the advantage of selecting wavelengths containing the implicit information. The combination of 1st-d’SG pretreatment and SPA-LSSVM show its applicable potential to predict the octane number in fuel petrol. Correlation coefficient ; Mean squared error ; Calibration ; Gasoline ; Octane ; Linear regression ; Coefficient of determination ; Mathematics ; Support vector machine ; Pearson product-moment correlation coefficient ; Chemistry ; Statistics ; Computer science ; Artificial intelligence Spectroscopy and Chemometric Analyses ; Advanced Chemical Sensor Technologies ; Water Quality Monitoring and Analysis
Authors: Kenji Tsuda
Source: Microscopy (article, 2018-10-26)
Field: Materials Science — Materials Chemistry

2pA_SS3-6Local structure analysis using convergent-beam electron diffraction Diffraction ; Electron diffraction ; Cathode ray ; Materials science ; Electron ; Beam (structure) ; Optics ; Physics ; Nuclear physics X-ray Diffraction in Crystallography ; Electron and X-Ray Spectroscopy Techniques ; Supramolecular Self-Assembly in Materials
Authors: Naveed Ahmad Dar | Kulraj Kaur
Source: International Journal of Emerging Trends in Engineering and Development (review, 2018-01-01)
Field: Materials Science — Materials Chemistry

Insulation Life Assement of High Voltage Transformer: A Review The life of the transformer depends upon the insulation of the transformer. It deteriorates with due course of time in operation. It happens because of the faults in the transformer. Several techniques are used to predict the fault to diagnose it, in order to increase the life of the transformer. various artificial techniques are also used for this purpose. This paper gives the review of life assessment of insulation of transformer and various techniques are discussed. High voltage ; Transformer ; Electrical engineering ; Materials science ; Reliability engineering ; Voltage ; Engineering High voltage insulation and dielectric phenomena ; Power Transformer Diagnostics and Insulation ; Thermal Analysis in Power Transmission
Authors: Piotr� Macio�
Source: Computer Methods in Material Science (article, 2018-01-01)
Field: Materials Science — Materials Chemistry

Rule-based controlling of a multiscale model of precipitation kinetics One of the most important obstacles of widening of multiscale modelling is its high computational demand. It is caused by the fact, that each of numerous fine scale models has comparable computational requirements to a coarse scale one. There are several ways of decreasing of computational time of multiscale models. Optimization of a structure of a model is one of the most promising. In this paper the Adaptive Multiscale Modelling Methodology is described, including Knowledge-Based adaptation of the multiscale model of precipitation kinetics during heat treatment. Core features of the methodology are introduced. The numerical model of heat treatment of an aluminium alloy based on the methodology and the dedicated framework is presented. Besides modelling of macroscopic heat transfer, models of precipitation kinetics based on thermodynamic calculations are included. To decrease computational requirements arising from coupling of the macroscale model and the thermodynamic models, metamodeling and similarity approaches are applied. Computations with several configuration of rules are described, as well as their results. Reliability and time consumption of computations are discussed. Future perspectives of combining of modelling and metamodeling in one, integrated model are discussed. Multiscale modeling ; Metamodeling ; Computational model ; Computation ; Computer science ; Scale (ratio) ; Coupling (piping) ; Surrogate model ; Simulation ; Mechanical engineering ; Machine learning ; Algorithm ; Chemistry ; Engineering Material Properties and Failure Mechanisms ; Advanced Mathematical Modeling in Engineering ; Material Properties and Applications
Authors: Alexeev Kirill S. | S. G. Alexeev | Barbin Nicolay M.
Source: Journal of Siberian Federal University Chemistry (article, 2018-06-01)
Field: Materials Science — Materials Chemistry

Prediction of Physical-Chemical and Fire Hazard Characteristics by Carbon Chain Rules.1. Alkanals Investigations of the dependence of physico-chemical and fire hazard properties from the chemical structure of alkanals are carried out. Forecasting the boiling temperature, the flash point, the temperature and concentration flammability limits, the heats of combustion and vaporization is performed by the rules of the carbon chain. For the convenience of practical application of the rules of the carbon chain, the following empirical equations for the calculation of physico-chemical and fire hazard indices from the conventional carbon chain and from the number of carbon atoms are proposed. A comparative analysis of the proposed methods for calculating the flash point and the methods of GOST 12.1.044-89, Mendeleev and ACD/Lab 2014 is carried out. It is shown that the new methods basically give more accurate calculation results than the comparison design procedures. Hazard ; Fire hazard ; Chain (unit) ; Environmental science ; Computer science ; Chemistry ; Organic chemistry ; Environmental protection ; Physics Thermal and Kinetic Analysis ; Fire dynamics and safety research ; Forensic Fingerprint Detection Methods