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INTERPOLATION WITH RESTRICTED ARC LENGTH

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Analysis in Theory and Applications 2003年第2期19卷 153-159页

作者： petar Petrov University of Sofia Bulgaria

For given datawe study constrained interpolation problem of Favard typewhere dx is the arc length of f in [0,1]. We prove the existence of a solution f, of the above problem, that is a quadratic spline with a second derivative f, . which coincides with one of the constants between every two consecutive knots. Thus, we extend a result of Karlin concerning Favard problem, to the case of restricted length interpolation.

关键词： interpolation knot quadratic spline

Importance of initial buoyancy field on evolution of mantle thermal structure:Implications of surface boundary conditions

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Geoscience Frontiers 2015年第1期6卷 3-22页

作者： petar Gliovi Alessandro M.Forte GEOTOP Universite du Quebec a MontrealCP 8888Succursale Centre-Ville

Although there has been significant progress in the seismic imaging of mantle heterogeneity, the outstanding issue that remains to be resolved is the unknown distribution of mantle temperature anomalies in the distant geological past that give rise to the present-day anomalies inferred by global tomography models. To address this question, we present 3-D convection models in compressible and self-gravitating mantle initialised by different hypothetical temperature patterns. A notable feature of our forward convection modelling is the use of self-consistent coupling of the motion of surface tectonic plates to the underlying mantle flow, without imposing prescribed surface velocities （i.e., p/ate-like boundary condition）. As an approximation for the surface mechanical conditions before plate tectonics began to operate we employ the no-slip （rigid） boundary condition. A rigid boundary condition dem- onstrates that the initial thermally-dominated structure is preserved, and its geographical location is fixed during the evolution of mantle flow. Considering the impact of different assumed surface boundary conditions （rigid and plate-like） on the evolution of thermal heterogeneity in the mantle we suggest that the intrinsic buoyancy of seven superplumes is most-likely resolved in the tomographic images of present-day mantle thermal structure. Our convection simulations with a plate-like boundary condition reveal that the evolution of an initial cold anomaly beneath the Java-lndonesian trench system yields a long-term, stable pattern of thermal heterogeneity in the lowermost mantle that resembles the present- day Large Low Shear Velocity Provinces （LLSVPs）, especially below the Pacific. The evolution of sub- duction zones may be, however, influenced by the mantle-wide flow driven by deeply-rooted and long- lived superplumes since Archean times. These convection models also detect the intrinsic buoyancy of the Perm Anomaly that has been identified as a unique slow feature d

关键词： Dynamics: convection currents, and mantleplumes Hotspots Seismic tomography Planetary tectonics CMB topography Perm Anomaly

Metasurfaces for next-generation wireless communication systems

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National Science Review 2023年第8期10卷 17-19页

作者： Younes Ra'di Nikita Nefedkin petar Popovski Andrea Alù Department of Electrical Engineering and Computer Science Syracuse University Photonics Initiative Advanced Science Research Center City University of New York Department of Electronic Systems Aalborg University Physics Program Graduate Center City University of New York

The pace of development in the world of 5G communication systems has proven to be much more demanding than previous generations, with 5G-Advanced seemingly around the corner [1]. Extensive research is already underway to structure the next generation of wireless systems(i.e. 6G), which may potentially enable an unprecedented level of human–machine interaction [2].

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Shell-isolated Nanoparticle-enhanced Raman Spectroscopy towards In-Situ Investigating of Interfacial Structure

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Chinese Journal of Structural Chemistry 2020年第8期39卷 1372-1376,1357页

作者： ZHANG Yue-Jiao RADJENOVIC petar M LI Jian-Feng College of Energy State Key Laboratory for Physical Chemistry of Solid SurfacesCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China

Since the discovery of surface-enhanced Raman spectroscopy(SERS),it has been rapidly applied to the in situ study of electrochemical ***-isolated nanoparticle-enhanced Raman spectroscopy(SHINERS)stands out as one of the most powerful tools for the in situ study of interfacial structures,especially on well-defined single crystal *** perspective paper focuses on the study of interfacial structures with the SHINERS technique,including the electronic structure of heterogeneous metal surfaces,and the detection of molecules absorbed on the surface,as well as intermediate species,during electrochemical ***,we present an outlook on future research and development of SHINERS for studying interfacial structures.

关键词： SHINERS single-crystal electrode spectroelectrochemistry interface structure in-situ

Heat Integration retrofit analysis --an oil refinery case study by Retrofit Tracing Grid Diagram

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Frontiers of Chemical Science and Engineering 2015年第2期9卷 163-182页

作者： Andreja NEMET Jiri Jaromir KLEMES petar Sabev VARBANOV Valter MANTELLI Centre for Process Integration and Intensification CPI2 Faculty of Information Technology Egyetem utca 10 8200 Veszprem Hungary IPLOM SpA Via C. Navone 3B 16012 Busalla Genoa Italy

Heat Integration has been established over the last decades as a proven chemical engineering methodol- ogy. Two design implementations are often used in the industry： grassroots and retrofit. Although various methods have been developed for retrofit, it still needs more development to ensure simultaneously thermodynamic feasibility and economic viability. In this paper, a novel graphical approach has been developed to facilitate the understanding of the current situation and scope of improvement. The Retrofit Tracing Grid Diagram presents all streams and heat exchangers in temperature scale and the heat exchangers are clearly separated from each other, enabling clear visualisation of the current state. The tool incorporates the previously developed Cross-Pinch Analysis as well as path approach for retrofit. Additionally, the non-vertical heat transfer can be evaluated. The application of the developed tool has been validated on an oil refinery case study. The applicability of the tool is evident as it can reveal additional options for modification that none of the previous methods considered.

关键词： Heat Integration retrofit Pinch Analysis,thermodynamic approach oil refinery

Preparation and Characterization of Thermoplastic Starch from Sugar Palm (Arenga pinnata) by Extrusion Method

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Journal of Renewable Materials 2023年第4期11卷 1963-1976页

作者： Muhammad Ghozali Yenny Meliana Widya Fatriasari petar Antov Mochamad Chalid Departement of Metallurgy and Material Universitas IndonesiaDepok16424Indonesia Research Center for Chemistry National Research and Innovation Agency(BRIN)Kawasan PUSPIPTEK SerpongTangerang Selatan15314Indonesia Research Center for Biomass and Bioproducts National Research and Innovation Agency(BRIN)Jl Raya Bogor KM 46 CibinongBogor16911Indonesia Faculty of Forest Industry University of ForestrySofia1797Bulgaria

Sugar palm(Arenga pinnata)starch is considered an important renewable,biodegradable,and eco-friendly polymer,which is derived from agricultural by-products and residues,with great potential for the development of biocomposite *** research was aimed at investigating the development of TPS biocomposites from *** palm starch using an extrusion *** starch,glycerol,and stearic acid were extruded in a twin-screw *** electron microscopy(SEM)analysis of TPS showed that the starch granules were damaged and gelatinized in the extrusion *** density of TPS was 1.3695 g/mL,lower than that of palm starch,and the addition of stearic acid resulted in increased TPS density.X-ray diffraction(XRD)results showed that palm starch had a C-type pattern crystalline *** tensile strength,elongation at break,and modulus of elasticity of TPS were 7.19 MPa,33.95%,and 0.56 GPa,*** addition of stearic acid reduced the tensile strength,elongation at break and modulus of elasticity of *** rheological properties,i.e.,melt flow rate(MFR)and viscosity of TPS,were 7.13 g/10 min and 2482.19 Pa.s,*** presence of stearic acid in TPS resulted in increased MFR and decreased viscosity *** peak gelatinization temperature of *** palm starch was 70°C,while Tg of TPS was 65°*** addition of stearic acid reduced the Tg of *** thermogravimetric analysis(TGA)analysis showed that the addition of glycerol and stearic acid decreased the thermal stability,but extended the temperature range of thermal *** derived from *** palm starch by extrusion method has the potential to be applied in industrial practice as a promising raw material for manufacturing bio-based packaging as a sustainable and green alternative to petroleum-based plastics.

关键词： Arenga pinnata sugar palm starch thermoplastic starch glycerol stearic acid twin-screw extruder biocomposites

Intelligent fault detection and location scheme for modular multi‐level converter multi‐terminal high‐voltage direct current

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High Voltage 2021年第1期6卷 125-137页

作者： Qingqing Yang Jianwei Li Ricardo Santos Kaijia Huang petar Igic Coventry University CoventryUK Department of Engineering Science University of OxfordOxfordUK Centre of Engineering Federal University of ABCSanto AndreBrazil DTU Energy Technical University of DenmarkKongens LyngbyDenmark

In order to overcome the drawbacks of the conventional protection methods in high‐voltage direct current transmission lines, a deep learning approach is proposed that directly learn the fault conditions based on unsupervised feature extraction to the detection and location decision by leveraging the hidden layer activations of recurrent neural network. The deep‐recurrent neural network boosting with the gated recurrent unit compared with the long short‐term memory unit is used by analysing both the signal presented in time domain and frequency domain. The proposed method is tested based on a modular multilevel converter based four‐terminal high‐voltage direct current system. Various faults under different conditions were simulated against fault resistance, external faults and small disturbance immunity with the validity, and the simulation verified a high accuracy, robustness and fast results because of the utilization of characteristic feature extraction.

关键词： fault overcome high

Art of Control of High Power IGBTs:From Theory to Practice-An Overview

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电力电子技术 2012年第12期46卷 8-17页

作者： petar J.Grbovic IEEE

The insulated gate bipolar transistor(IGBT) was invented in early 80s as the controlled switch to replace HV MOSFETs and ***,the IGBT is the major player in most of power conversion applications,such as home appliance drives,power supplies,lighting,industrial variable speed drives,UPS,medical equipment,traction drives, power transmission,etc..As fully controlled device,die IGBT requires an appropriate gate driver in order to achieve full performances of the *** author of this paper has tried to systematically summarize some major aspects of application and control of high power as well low power *** major aspects considered are the IGBT losses,gate driver and protection techniques.

关键词： IGBTs 电力电子技术 MOSFET 晶体管

Exciton dynamics in different aromatic hydrocarbon systems

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Chinese Physics B 2020年第10期29卷 438-443页

作者： Milica Rutonjski petar Mali Slobodan Radosevic Sonja Gombar Milan Pantic Milica Pavkov-Hrvojevic Department of Physics Faculty of SciencesUniversity of Novi SadTrg Dositeja Obradovicu 421000 Novi SadSerbia

The exciton dispersion is examined in the case of four selected prototypical molecular solids: pentacene, tetracene, picene, and chrysene. The model parameters are determined by fitting to experimental data obtained by inelastic electron scattering. Within the picture that relies on Frenkel-type excitons we obtain that theoretical dispersion curves along different directions in the Brillouin zone are in good agreement with the experimental data, suggesting that the influence of charge-transfer excitons on exciton dispersion of the analyzed organic solids is not as large as proposed. In reciprocal space directions where Davydov splitting is observed we employ the upgraded version of Hamiltonian used in Materials 11, 2219 (2018).

关键词： aromatic hydrocarbons exciton dispersion Heisenberg model Davydov splitting