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Evaluation of Inherent Uncertainties of the Homogeneous Effective Thermal Conductivity Approach in Modeling of Printed Circuit Boards for Space Applications

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Journal of Electronics Cooling and Thermal Control 2013年第1期3卷 35-41页

作者： Rafael Lopes Costa valeri vlassov Space Mechanics and Control Division/National Institute for Space Research(DMC/INPE) Sao Jose dos CamposBrazil

Electronic components are normally assembled to printed circuit boards (PCBs). Such components generate heat in operation which must be conducted away efficiently from the small mounting areas to frames where the PCB is fixed. The temperature of the component depends on heat dissipation rate, technology and parameters of mounting, component placement and finally effective thermal conductivity (keff) of the board. The temperature of some components may reach significant magnitudes over 100°C while the PCB frame is kept at near-ambient temperature. The reliability of electronic components is directly related to operating temperature;?so the thermal project should be able to provide a correct temperature prediction of all PCB components under the hottest operational condition. In space applications, the main way to spread and reject heat of electronic equipment is by thermal conduction once there is no air available to apply convection-based cooling techniques. The PCB keff is an important parameter for the electronics thermal analysis when the PCB is modeled as a simplified homogeneous board with a unique thermal conductivity. In this paper, an intrinsic uncertainty of such approach is firstly reveled and its magnitude is evaluated for a real space use PCB. The simulation uses SINDA/FLUINT Thermal Desktop and aims to determine the keff of the PCB by comparison between a detailed multi-layered anisotropic model and an equivalent homogeneous single-layer model. The model was validated using available data for two-layered FR4-copper PCB. Multiple simulations are performed with different dissipating component position and mounting area.

关键词： PCB Spacecraft Thermal Control Effective Conductivity

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Extravasated contrast volumetric assessment on computed tomography angiography in gastrointestinal bleeding:A useful predictor of positive angiographic findings

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World Journal of Radiology 2024年第5期16卷 115-127页

作者： Laura Maria Cacioppa Chiara Floridi Alessandra Bruno NicolòRossini Tommaso valeri Alessandra Borgheresi Riccardo Inchingolo Francesco Cortese Giacomo Novelli Alessandro Felicioli Mario Torresi Pietro Boscarato Letizia Ottaviani Andrea Giovagnoni Division of Interventional Radiology Department of Radiological SciencesUniversity Politecnica Delle MarcheAncona 60126Italy Department of Clinical Special and Dental SciencesUniversity Politecnica Delle MarcheAncona 60126Italy Division of Radiology Department of Radiological SciencesUniversity Hospital"Azienda Ospedaliero Universitaria Delle Marche"Ancona 60126Italy Interventional Radiology Unit "F Miulli"Regional General HospitalAcquaviva delle Fonti 70021Italy Department of Radiology IRCCS INRCAAncona 60126Italy

BACKGROUND Gastrointestinal bleeding(GIB)is a severe and potentially life-threatening condition,especially in cases of delayed *** tomography angiography(CTA)plays a pivotal role in the early identification of upper and lower GIB and in the prompt treatment of the *** To determine whether a volumetric estimation of the extravasated contrast at CTA in GIB may be a predictor of subsequent positive angiographic *** In this retrospective single-centre study,35 patients(22 men;median age 69 years;range 16-92 years)admitted to our institution for active GIB detected at CTA and further submitted to catheter angiography between January 2018 and February 2022 were ***-three(65.7%)patients underwent endoscopy before *** volumetry was evaluated in both arterial and venous phases via a semi-automated dedicated *** rate was obtained from volume change between the two phases and standardised for unit *** were divided into two groups,according to the angiographic signs and their concordance with *** Upper bleeding accounted for 42.9%and lower GIB for 57.1%.Mean haemoglobin value at the admission was 7.7 g/dL.A concordance between positive CTA and direct angiographic bleeding signs was found in 19(54.3%)*** no significant differences in terms of bleeding volume in the arterial phase(0.55 mL vs 0.33 mL,P=0.35),a statistically significant volume increase in the venous phase was identified in the group of patients with positive angiography(2.06 mL vs 0.9 mL,P=0.02).In the latter patient group,a significant increase in bleeding rate was also detected(2.18 mL/min vs 0.19 mL/min,P=0.02).CONCLUSION In GIB of any origin,extravasated contrast volumetric analysis at CTA could be a predictor of positive angiography and may help in avoiding further unnecessary procedures.

关键词： Gastrointestinal haemorrhage Computed tomography angiography Volumetric analysis Computer-assisted image interpretation Therapeutic embolization Transcatheter arterial embolization

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Highly efficient transient stimulated Raman scattering on secondary vibrational mode of BaWO_(4) crystal due to its constructive interference with self-phase modulation

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Chinese Optics Letters 2023年第3期21卷 113-117页

作者： Igor Kinyaevskiy valeri Kovalev Pavel Danilov Nikita Smirnov Sergey Kudryashov Andrey Koribut Andrey Ionin P.N.Lebedev Physical Institute of the Russian Academy of Sciences Moscow 119991Russia

An exceptionally high stimulated Raman scattering[SRS]conversion efficiency to the first Stokes component associated with the secondary[low-frequency and low intensity]vibrational mode v2[~330 cm^[-1]]was observed in a BaWO4 crystal in a highly transient regime of *** effect takes place in the range of pump pulse energy from~0.1 to~0.5μJ with maximum energy conversion efficiency up to 35%at 0.2μ*** nature of the observed effects is explained by interference of SRS and self-phase modulation,where the latter is related to a noninstantaneous orientational Kerr nonlinearity in the BaWO4 crystal.

关键词： stimulated Raman scattering secondary vibrational mode self-phase modulation ultrashort laser pulses transient phenomena

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Hole-doping induced ferromagnetism in 2D materials

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npj Computational Materials 2022年第1期8卷 2180-2189页

作者： Ruishen Meng Lino da Costa Pereira Jean-Pierre Locquet valeri Afanas’ev Geoffrey Pourtois Michel Houssa Department of Physics and Astronomy KU LeuvenCelestijnenlaan 200DLeuvenB-3001Belgium imec Kapeldreef 75B-3001LeuvenBelgium

Two-dimensional(2D)ferromagnetic materials are considered as promising candidates for the future generations of spintronic ***,2D materials with intrinsic ferromagnetism are ***,high-throughput first-principles simulations are performed to screen 2D materials that present a non-magnetic to a ferromagnetic transition upon hole doping.A global evolutionary search is subsequently performed to identify alternative possible atomic structures of the eligible candidates,and 122 materials exhibiting a hole-doping induced ferromagnetism are *** energetic and dynamic stability,as well as magnetic properties under hole doping are investigated *** of these 2D materials are metal halides,followed by chalcogenides,oxides,and nitrides,some of them having predicted Curie temperatures above 300 *** exchange interactions responsible for the ferromagnetic order are also *** work not only provides theoretical insights into hole-doped 2D ferromagnetic materials,but also enriches the family of 2D magnetic materials for possible spintronic applications.

关键词： ferromagnetic doping materials

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Deep reinforcement learning for quantum multiparameter estimation

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Advanced Photonics 2023年第1期5卷 58-70页

作者： valeria Cimini Mauro valeri Emanuele Polino Simone Piacentini Francesco Ceccarelli Giacomo Corrielli NicolòSpagnolo Roberto Osellame Fabio Sciarrino Sapienza Universitàdi Roma Dipartimento di FisicaRomaItaly Istituto di Fotonica e Nanotecnologie Consiglio Nazionale delle RicercheMilanoItaly

Estimation of physical quantities is at the core of most scientific research,and the use of quantum devices promises to enhance its *** real scenarios,it is fundamental to consider that resources are limited,and Bayesian adaptive estimation represents a powerful approach to efficiently allocate,during the estimation process,all the available ***,this framework relies on the precise knowledge of the system model,retrieved with a fine calibration,with results that are often computationally and experimentally *** introduce a model-free and deep-learning-based approach to efficiently implement realistic Bayesian quantum metrology tasks accomplishing all the relevant challenges,without relying on any a priori knowledge of the *** overcome this need,a neural network is trained directly on experimental data to learn the multiparameter Bayesian *** the system is set at its optimal working point through feedback provided by a reinforcement learning algorithm trained to reconstruct and enhance experiment heuristics of the investigated quantum ***,we prove experimentally the achievement of higher estimation performances than standard methods,demonstrating the strength of the combination of these two black-box algorithms on an integrated photonic *** work represents an important step toward fully artificial intelligence-based quantum metrology.

关键词： quantum sensing integrated photonics machine learning for metrology

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Electroextraction of neodymium from LiCl-KCl melt using binary liquid Ga-Al cathode

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Journal of Rare Earths 2023年第8期41卷 1250-1257,I0005页

作者： Li Ding Xuepeng Wang Yongde Yan valeri Smolenski Wenda Xu Alena Novoselova Yun Xue Fuqiu Ma Xingmei Zhang Key Laboratory of Superlight Materials and Surface Technology Ministry of EducationCollege of Materials Science and Chemical EngineeringHarbin Engineering UniversityHarbin 150001China Yantai Research Institute of Harbin Engineering University Yantai 264006China Institute of High-Temperature Electrochemistry UB RAS Ekaterinburg 620990Russia Department of Rare Metals and Nanomaterials Institute of Physics and TechnologyUral Federal UniversityEkaterinburg 620990Russia Yantai Standard Metrology Inspection&Test Center National Steam Flowrate Measurement StationYantai 264000China

The electrochemical behaviour of Nd(Ⅲ)ion was investigated on inert W,active Ga and Ga-AI *** is established that the reduction of Nd(Ⅲ)ion on the inert electrode is a consecutive two-step process while that on the active electrodes is a one-step *** apparent standard potential of the Nd(Ⅲ)/Nd redox couple at different temperatures was determined by open-circuit chronopotentiometry and semi-differential method,and the relationship between temperature and apparent standard potential was further *** thermodynamic properties of Nd in Ga and Ga-Al electrodes such as activity coefficient and activity were evaluated via intermittent coulomb titration and temperature dependence test,and the effect of temperature on activity coefficient was ***,Nd was successfully extracted in form of alloy from molten salt by galvanostatic electrolysis,in which the current efficiency of91.7%for the electroextraction indicates that the binary liquid Ga-Al electrode has favorable performance.

关键词： Rareearths Electroextraction Spent nuclear fuel Pyrochemical processing Lanthanides Binary liquid cathode

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Why the Incoherent Paradigm Is for the Future Wireless Networks?

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Communications and Network 2023年第3期15卷 65-82页

作者： valeri Kontorovich Electrical Engineering Department Communications Section CINVESTAV-IPN Mexico City Mexico

This material is aimed to attract attention to the “incoherent approach for power NOMA-RIS-MIMO transmission in wireless channels”. Such kind of approach might be successfully applied in future dense networks formed by High-Speed Vehicles (HSV networks, etc.). Those scenarios take place in doubly selective communication channels typical for such kind of radio networks. The proposal for the presented hereafter incoherent view (“paradigm”) is based on several basic principles: 1) Shift from the “coherent “ideology”, i.e. rejection of the application of any type of Channel State Information (CSI, CSIT);2) Application of the so-called “invariant” to the communication channel’s features (distortions) modulation technique together with its incoherent demodulation;3) Orthogonal channel decomposition by means of “universal” eigen basis (in the form of Prolate Spheroidal Wave Functions, PSWF) as “artificial trajectories” of wave propagation;4) Chaotic filtering (chaos parameter settings as UE signatures) together with sequential multiuser parallel detection algorithms for users’ identification (classification). It is shown that the proposed approach might provide an effective use of the radio resource and it is relatively simple for implementation.

关键词： Incoherent Processing Universal Eigen Functions Chaos Filtering Invariant Modulation

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Orbital angular momentum based intra- and interparticle entangled states generated via a quantum dot source

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先进光子学(英文) 2023年第4期5卷 74-84页

作者： Alessia Suprano Danilo Zia Mathias Pont Taira Giordani Giovanni Rodari Mauro valeri Bruno Piccirillo Gonzalo Carvacho Nicolo Spagnolo Pascale Senellart Lorenzo Marrucci Fabio Sciarrino Sapienza Universitàdi Roma Dipartimento di FisicaRomaItaly Universite Paris-Saclay UMR 9001Centre for Nanosciences and NanotechnologyCNRSPalaiseauFrance Universitàdi Napoli Federico II Complesso Universitario di Monte Sant’AngeloDipartimento di Fisica“Ettore Pancini”NapoliItaly INFN-Sezione di Napoli NapoliItaly

Engineering single-photon states endowed with orbital angular momentum (OAM) is a powerful toolfor quantum information photonic implementations. Indeed, due to its unbounded nature, OAM is suitable forencoding qudits, allowing a single carrier to transport a large amount of information. Most of the experimentalplatforms employ spontaneous parametric down-conversion processes to generate single photons, evenif this approach is intrinsically probabilistic, leading to scalability issues for an increasing number of *** quantum dots (QDs) have been used to get over these limitations by producing on-demand pure and indistinguishable single-photon states, although only recently they have been exploitedto create OAM modes. Our work employs a bright QD single-photon source to generate a complete set ofquantum states for information processing with OAM-endowed photons. We first study hybrid intraparticleentanglement between OAM and polarization degrees of freedom of a single photon whose preparationwas certified by means of Hong–Ou–Mandel visibility. Then, we investigate hybrid interparticle OAM-based entanglement by exploiting a probabilistic entangling gate. The performance of our approach isassessed by performing quantum state tomography and violating Bell inequalities. Our results pave theway for the use of deterministic sources for the on-demand generation of photonic high-dimensionalquantum states.

关键词： orbital angular momentum quantum dot intraparticle entanglement interparticle entanglement Bell violation

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METHOD FOR MAKING EXPLOSIVE CHARGES BY FILTERING LIQUID EXPLOSIVE

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含能材料 1993年第1期 27-30页

作者： vlassov D A St-Petersburg Technological Institute

The process of sensitive explosive charges making is dangerous and re-quires complicated technological *** multi-component composition making,different mixing devices necessary cause mechanical effects on the processed material,which can lead to ignition and even to *** St-Petersburg Technological Insti-tute a new method which is free of these shortcomings is worked out for making explo-sive charge of powerful crystal explosive with melt explosive or liquid polymer.

关键词： explosive technology filtering TNT RDX.

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Comparative equilibrium studies of sorption of Pb(Ⅱ) ions by sodium and calcium alginate

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Journal of Environmental Sciences 2008年第7期20卷 827-831页

作者： KHOTIMCHENKO Maxim KOVALEV valeri KHOTIMCHENKO Yuri Department of pharmacy Vladivostok State Medical UniversityVladivostok 690990Russia Laboratory of Pharmacology Institute of Marine BiologyFar East Branch of Russian Academy of SciencesVladivostok 690041Russia. Laboratory of Pharmacology Institute of Marine BiologyFar East Branch of Russian Academy of SciencesVladivostok 690041Russia.Department of pharmacyVladivostok State Medical UniversityVladivostok 690990Russia

The absorption of Pb(Ⅱ) ions from aqueous solution by different alginate compounds was studied in a batch sorption *** soluble sodium alginate and insoluble calcium alginate beads were *** lead-binding capacity of both alginate compounds was highest within the pH range *** binding capacities and rates of Pb(lI) ions by alginate compounds were *** Langmuir,Freundlich,and Bruneaur,Emmet and Teller (BET) sorption models were applied to describe the isotherms and isotherm con...

关键词： heavy metal lead equilibrium study alginate wastewater

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