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Wyniki wyszukiwania dla: MONITORING OF OFFSHORE STRUCTURES
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A simplified approach to determine the expiration date of certified reference material based on the results of monitoring long-term stability
PublikacjaAll components of the quality assurance (QA) system for measurement results depend heavily on certified reference materials (CRMs). There is a need for a comprehensive discussion of the stability study using the CRM statistical method. Monitoring involves periodic sampling and analysis of the CRM at predetermined intervals to continuously monitor stability without compromising its integrity. The obtained stability data is then...
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Cost-Efficient Surrogate Modeling of High-Frequency Structures Using Nested Kriging with Automated Adjustment of Model Domain Lateral Dimensions
PublikacjaSurrogate models are becoming popular tools of choice in mitigating issues related to the excessive cost of electromagnetic (EM)-driven design of high-frequency structures. Among available techniques, approximation modeling is by far the most popular due to its versatility. In particular, the surrogates are exclusively based on the sampled simulation data with no need to involve engineering insight or problem-specific knowledge....
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The advanced monitoring as a key factor for appropriate optimization and control of full-scale activated sludge systems – case study Debogorze WWTP.
PublikacjaComputer simulation has become a helpful tool in wastewater treatment systems performance and effectiveness analysis. Advanced monitoring, by using appropriate software, enables to create a mathematical model of a real wastewater treatment plant (WWTP), run a simulation and subsequently interpret results under various conditions. An operation of WWTP is usually controlled by global parameters such as flow, solids retention time,...
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Scalability of surrogate-assisted multi-objective optimization of antenna structures exploiting variable-fidelity electromagnetic simulation models
PublikacjaMulti-objective optimization of antenna structures is a challenging task due to high-computational cost of evaluating the design objectives as well as large number of adjustable parameters. Design speedup can be achieved by means of surrogate-based optimization techniques. In particular, a combination of variable-fidelity electromagnetic (EM) simulations, design space reduction techniques, response surface approximation (RSA) models,...
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Reliable data-driven modeling of high-frequency structures by means of nested kriging with enhanced design of experiments
PublikacjaData-driven (or approximation) surrogate models have been gaining popularity in many areas of engineering and science, including high-frequency electronics. They are attractive as a way of alleviating the difficulties pertinent to high computational cost of evaluating full-wave electromagnetic (EM) simulation models of microwave, antenna, and integrated photonic components and devices. Carrying out design tasks that involve massive...
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Automatic Identification System (AIS) Dynamic Data Integrity Monitoring and Trajectory Tracking Based on the Simultaneous Localization and Mapping (SLAM) Process Model
PublikacjaTo enhance the safety of marine navigation, one needs to consider the involvement of the automatic identification system (AIS), an existing system designed for ship-to-ship and shipto- shore communication. Previous research on the quality of AIS parameters revealed problems that the system experiences with sensor data exchange. In coastal areas, littoral AIS does not meet the expectations of operational continuity and system availability,...
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Fast multi-objective optimization of antenna structures by means of data-driven surrogates and dimensionality reduction
PublikacjaDesign of contemporary antenna structures needs to account for several and often conflicting objectives. These are pertinent to both electrical and field properties of the antenna but also its geometry (e.g., footprint minimization). For practical reasons, especially to facilitate efficient optimization, single-objective formulations are most often employed, through either a priori preference articulation, objective aggregation,...
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Monitoring of crosslinking of a DGEBA-PAMAM adhesive in composite/aluminium bonded joint using mechanical and ultra-sound techniques
PublikacjaAdhesive cure is an important and determining aspect of strength and stability of bonded structures. Crosslinking of the polymer leads to the adhesive strength, stiffness and durability. Depending on the resin and curing agent used, cure time can vary from minutes to weeks, even then 100% crosslinking not being guaranteed. Standard methods based on dynamic mechanical analysis (DMA) or calorimetric techniques (DSC, DTA) are valuable...
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Changes on the Surface of the SiO2/C Composite, Leading to the Formation of Conductive Carbon Structures with Complex Nature of DC Conductivity
PublikacjaSol–gel layers have been the subject of many studies in recent decades. However, very little information exists about layers in which carbon structures are developed in situ. Using the spin-coating method, we obtained thin iron-doped SiO2/C composite films. The results of Raman spectroscopy showed that our samples consisted of graphitic forms and polymers. The latter’s contribution decreases with rising temperature. FTIR and EDS...
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Determination of Vehicles Load Equivalency Factors for Polish Catalogue of Typical Flexible and Semi-rigid Pavement Structures
PublikacjaThe new Polish Catalog of Typical Flexible and Semi-rigid Pavement Structures was introduced to use in practice in 2014. Much of works were focused on actualization of vehicles load equivalency factors. For this purpose data delivered from weigh-inmotion were analyzed. Four methods of determination of load equivalency factors for pavement structure design were compared. The analysis showed that fourth power equation, AASHTO 1993...
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Variable Data Structures and Customized Deep Learning Surrogates for Computationally Efficient and Reliable Characterization of Buried Objects
PublikacjaIn this study, in order to characterize the buried object via deep-learning-based surrogate modeling approach, 3-D full-wave electromagnetic simulations of a GPR model has been used. The task is to predict simultaneously and independent of each characteristic parameters of a buried object of several radii at different positions (depth and lateral position) in various dispersive subsurface media. This study has analyzed variable...
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PRELIMINARY FIELD TESTS AND LONG-TERM MONITORING AS A METHOD OF DESIGN RISK MITIGATION: A CASE STUDY OF GDAŃSK DEEPWATER CONTAINER TERMINAL
PublikacjaAppropriate risk assessment plays a fundamental role in the design. . The authors propose a possible method of design risk mitigation, which follows recommendations included in Eurocode 7. The so-called “Observational Method” (OM) can produce savings in costs and programmes on engineering projects without compromising safety. The case study presented is a complex design solution that deals with the heavy foundations of a gantry...
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Monitoring Steel Bolted Joints during a Monotonic Tensile Test Using Linear and Nonlinear Lamb Wave Methods: A Feasibility Study
PublikacjaThe structural integrity of steel bolted joints may be compromised due to excessive loading. Therefore, condition assessment and the detection of potential defects before they cause a failure have become a major issue. The paper is focused on the condition monitoring of a bolted lap joint subjected to progressive degradation in a tensile test. The inspection used Lamb waves propagated through the overlap area. Wave propagation...
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Dispersive Delay Structures With Asymmetric Arbitrary Group-Delay Response Using Coupled-Resonator Networks With Frequency-Variant Couplings
PublikacjaThis article reports the design of coupled-resonatorbased microwave dispersive delay structures (DDSs) with arbitrary asymmetric-type group delay response. The design process exploits a coupling matrix representation of the DDS circuit as a network of resonators with frequency-variant couplings (FVCs). The group delay response is shaped using complex transmission zeros (TZs) created by dispersive cross-couplings. We also present an...
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Offshore benthic habitat mapping based on object-based image analysis and geomorphometric approach. A case study from the Slupsk Bank, Southern Baltic Sea
PublikacjaBenthic habitat mapping is a rapidly growing field of underwater remote sensing studies. This study provides the first insight for high-resolution hydroacoustic surveys in the Slupsk Bank Natura 2000 site, one of the most valuable sites in the Polish Exclusive Zone of the Southern Baltic. This study developed a quick and transparent, automatic classification workflow based on multibeam echosounder and side-scan sonar surveys to...
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Low-Cost and Precise Automated Re-Design of Antenna Structures Using Interleaved Geometry Scaling and Gradient-Based Optimization
PublikacjaDesign of contemporary antennas is an intricate endeavor involving multiple stages, among others, tuning of geometry parameters. In particular, re-designing antennas to different operating frequencies, makes parametric optimization imperative to ensure the best achievable system performance. If the center frequency at the current design is distant from the target one, local tuning methods generally fail, whereas global algorithms...
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An interval estimator for chlorine monitoring in drinking water distribution systems under uncertain system dynamics, inputs and chlorine concentration measurement errors
PublikacjaThe design of an interval observer for estimation of unmeasured state variables with application to drinking water distribution systems is described. In particular, the design process of such an observer is considered for estimation of the water quality described by the concentration of free chlorine. The interval observer is derived to produce the robust interval bounds on the estimated water quality state variables. The stability...
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Coordination complexes of Mn(II), Co(II), Ni(II), Zn(II) and Cd(II) with histaminol – Crystal structures and formation constants in aqueous solution
PublikacjaStability constants were determined for a series of coordination complexes of Mn(II), Co(II), Ni(II), Zn(II) and Cd(II) with histaminol in aqueous solution. The tendency of histaminol to form chelate complexes has been confirmed by the isolation of several complex species in the monocrystalline form and determination of their molecular structures.
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Proton transfer and hydrogen bonds in supramolecular, self-assembled structures of imidazolium silanethiolates. X-ray, spectroscopic and theoretical studies
PublikacjaThe reaction of 1-methylimidazole, 2-ethyl-4-methylimidazole and 2-ethylimidazole with tris(2,6- diisopropylphenoxy)silanethiol (TDST) leads to the formation of three new salts, which have been characterized by elemental analyses, thermogravimetric analyses, FTIR spectroscopy, and their structures were determined by single-crystal X-ray diffraction. Structural analyses indicate that in all three compounds a proton transfer has...
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Rapid Variable-Resolution Parameter Tuning of Antenna Structures Using Frequency-Based Regularization and Sparse Sensitivity Updates
PublikacjaGeometry parameter tuning is an inherent part of antenna design process. While most often performed in a local sense, it still entails considerable computational expenses when carried out at the level of full-wave electromagnetic (EM) simulation models. Moreover, the optimization outcome may be impaired if good initial design is not available. This paper proposes a novel approach to fast and improved-reliability gradient-based...
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Model Management for Low-Computational-Budget Simulation-Based Optimization of Antenna Structures Using Nature-Inspired Algorithms
PublikacjaThe primary objective of this study is investigation of the possibilities of accelerating nature-inspired optimization of antenna structures using multi-fidelity EM simulation models. The primary methodology developed to achieve acceleration is a model management scheme which the level of EM simulation fidelity using two criteria: the convergence status of the optimization algorithm, and relative quality of the individual designs...
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Enhanced electrochemical activity of boron-doped nanocarbon functionalized reticulated vitreous carbon structures for water treatment applications
PublikacjaAn extraordinary charge transfer kinetics and chemical stability make a boron-doped diamond (BDD) a prom- ising material for electrochemical applications including wastewater treatment. Yet, with flat geometrical sur- faces its scaling options are limited. In this study, the reticulated Vitreous Carbon (RVC) served as a substrate for boron-doped diamondized nanocarbons (BDNC) film growth resulting with complex heterogeneity carbon structures...
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Monitoring Lead Concentration in the Surrounding Environmental Components of a Lead Battery Company: Plants, Air and Effluents—Case Study, Kenya
PublikacjaLead (Pb) pollution from smelters and lead–acid battery has become a serious problem worldwide owing to its toxic nature as a heavy metal. Stricter regulations and monitoring strategies have been formulated, legislated and implemented in various parts of the world on heavy metal usage. Developed countries such as the USA and in Europe largely operate within the set standards, however, developing countries such as Kenya, Nigeria...
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Application of lightweight cement composite with foamed glass aggregate in shell structures
PublikacjaThe purpose of the paper is to investigate the abilities of applying Granulated Expanded Glass Aggregate (GEGA) as a natural volume substitute of aggregate as a component of lightweight concrete. The GEGA aggregates used in the experiments were made of confused glass waste. In order to achieve satisfactory strength of concrete Granulated Ash Aggregate (GAA) was added as well. To produce specimens three grain sizes of aggregates...
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Centralized and Distributed Structures of Intelligent Systems for Aided Design of Ship Automation
PublikacjaA design process and accepted solutions made during this process, often base on non-formalized knowledge, obtained from designer (expert) intuition and practice. There are no formalized rules assuring the correctness of design solutions. The analysis of design process of ship automation, including ship power system, shows that this process can be supported by application of the artificial intelligence elements. The article presents...
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Environmental aspects of coastal earth structures made of soil-ash composites
PublikacjaThis paper presents an innovative technology of building the coastal dams with the use of soil-ash composites. A natural- scale test stand and results of the performed environmental tests are presented ; they have been compared with standards for purity of soils and waters. Also, an analysis of the obtained results and discussion of trends and anomalies in the observations, are given.
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A Stabilized Complex LOBPCG Eigensolver for the Analysis of Moderately Lossy EM Structures
PublikacjaThis letter proposes a stabilized locally optimal block preconditioned conjugate gradient method for computing selected eigenvalues for complex symmetric generalized non-Hermitian eigenproblems. Effectiveness of the presented approach is demonstrated for a moderately lossy dual-mode dielectric resonator, modeled using finite-element method with higher order elements
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The use of Response Surface Methodology for reliability estimation of composite engineering structures
PublikacjaStability loss is one of the key issues in the analysis of shells made of composite materials. This paper aims at finding the variation of the critical or limit value of the load resulting from geometric imperfections. An axially compressed 16-layer cylindrical panel model is considered. The imperfections of the panel are simulated as random fields. The parameters of these fields are used as the basic variables of the reliability...
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Path-based methods on categorical structures for conceptual representation of wikipedia articles
PublikacjaMachine learning algorithms applied to text categorization mostly employ the Bag of Words (BoW) representation to describe the content of the documents. This method has been successfully used in many applications, but it is known to have several limitations. One way of improving text representation is usage of Wikipedia as the lexical knowledge base – an approach that has already shown promising results in many research studies....
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A concept of an application to plan the time lines of building selected bridge structures
PublikacjaW rozdziale został przedstawiony przykład autorskiego programu komputerowego przeznaczonego do planowania czasu pracy i kosztów w budownictwie mostowym. Zaletą programu jest możliwość przedstawienia wyników w formie graficznej w sposób deterministyczny i niedeterministyczny. Ma to ogromne znaczenie jeżeli poszukujemy optymalnych rozwiązań dotyczących zagadnień ryzyka i ekonomiki budownictwa.
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Prefabricated structures under earthquake excitation: damage and failure of connection joints
PublikacjaCelem artykułu jest analiza zachowania się złączy pomiędzy elementami belkowymi a słupami w konstrukcjach prefabrykowanych poddanych obciążeniom dynamicznym powstającym podczas trzęsień ziemi. Wyniki przedstawione w pracy, uzyskane na podstawie badań numerycznych przeprowadzonych dla wybranego modelu konstrukcji, pokazują, iż złącza są najsłabszym elementem wymagającym zwrócenia szczególnej uwagi przy projektowaniu konstrukcji...
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CAVER 3.0: A Tool for the Analysis of Transport Pathways in Dynamic Protein Structures
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The use of response surface methodology for reliability estimation of composite engineering structures
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Application of decision–making parametric structures in the analysis of a compound planetary gear
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An Approximate Linear Analysis of Structures Utilizing Incremental Loading of Force Method
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An Experimental Study on the Effect of Temperature on Acoustic Emission Characteristics in Metallic Structures
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Double amino acid – A novel molecule enabling peptide interpenetrating structures
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The K X-ray line structures for a warm dense copper plasma
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Study of structures and properties of the laser cladding exhaust valve after service
PublikacjaPrzylgnie zaworów wydechowych silnie obciążonego silnika okrętowego zostały pokryte warstwą wykonana ze stopu kobaltu za pomocą techniki napawania laserowego. Tak przygotowane zawory były eksploatowane przez 3000 godzin w silniku Daru Młodzieży. Po tym czasie zostały zdemontowane i poddane szczegółowej analizie. Warunki pracy spowodowały powstanie na powierzchni przylgni warstwy tlenków o różnej grubości, wykazującej skłonność...
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Wave propagation modelling in 1D structures using spectral finite elements
PublikacjaW artykule omówiono modele propagacji fal wzdłużnych i poprzecznych w prętach oparte na dwóch sformułowaniach (w dziedzinie częstości i w dziedzinie czasu) metody elemntów spektralnych. Porównano otrzymane wyniki z wynikami eksperymentu.
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Multilayered structures examination using polarization sensitive optical coherence tomography
PublikacjaW artykule przedstawiono wstępne wyniki badań struktur warstwowych z użyciem systemu optycznej tomografii koherentnej z analizą stanu poaryzacji (PS-OCT). Omówiono budowę systemu oraz zakres stosowalności metody do badania złożonych struktur warstwowych.
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Influence of sulphur on high temperature degradation of steel structures in the refinery industry
PublikacjaArtykuł stanowi przegląd skutków wpływu związków siarki, znajdujących się w mediach procesowych instalacji rafineryjnych, na elementy konstrukcji ze stali węglowych i stopowych. Wyróżniono dwa aspekty wysokotemperaturowej korozji siarkowej: związany z tworzeniem się zgorzeliny siarczkowej i ubytkami masy oraz dotyczący wewnętrznej degradacji elementu w wyniku zmian mikrostruktury stali. Przedstawiono tzw. zmodyfikowane krzywe McConomy...
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On EM-driven size reduction of antenna structures with explicit constraint handling
PublikacjaSimulation-driven miniaturization of antenna components is a challenging task mainly due to the presence of expensive constraints, evaluation of which involves full-wave electromagnetic (EM) analysis. The recommended approach is implicit constraint handling using penalty functions, which, however, requires a meticulous selection of penalty coefficients, instrumental in ensuring optimization process reliability. This paper proposes...
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Accurate modelling of microwave structures using shape-preserving response prediction
PublikacjaArtykuł prezentuje metodologię dokładnego modelowania struktur mikrofalowych. Jest to zmodyfikowana wersja techniki opartej na procedurze przewidywania odpowiedzi z zachowaniem kształtu (shape-preserving response prediction, SPRP), która oszacowuje odpowiedź struktury mikrofalowej otrzymanej poprzez kosztowną obliczeniowo symulację elektromagnetyczną za pomocą taniego obliczeniowo modelu tejże struktury. Modyfikacja polega na wykorzystaniu...
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Technologies for Joining and Forming Thin-Walled Structures in the Construction of Transportation Vehicles
PublikacjaEditorial
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Conditional random field simulation of ground motions for large shell structures.
PublikacjaZaprezentowano metodę stochastycznego modelowania efektu propagacji fali trzęsienia ziemi i analizowano wpływ tego efektu na konstrukcje powłokowe znacznych rozmiarów. Symulowane przy użyciu tej metody rejestry trzęsień ziemi w wybranych punktach podporowych mogą być wykorzystane do analizy dynamicznej zachowania się konstrukcji. Przykładem analizowanej konstrukcji budowlanej jest zbiornik cylindryczny o średnicy 100 m.
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Pounding of structures during earthquakes modelled by nonlinear viscoelastic impact element.
PublikacjaAnalizowano zderzenia konstrukcji budowlanych podczas trzęsień ziemi wykorzystując model lepkosprężysty siły zderzenia. W analizie, zachowanie konstrukcji o różnych własnościach dynamicznych symulowane jest modelem dyskretnym o skupionych masach. wyniki badań pokazują, iż zderzenie może prowadzić do znacznego wzrostu odpowiedzi konstrukcji mniej sztywnej i lżejszej.
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On long-term prediction of stresses in principal members of ship hull structures.
PublikacjaOpisano krytycznie wymagania towarzystw klasyfikacyjnych dotyczące oceny wytrzymałości wzdłużnych wiązarów i wzdłużnych usztywnień poszycia kadłuba statku. Przedstawiono sposób prognozowania długoterminowego dynamicznych składowych tych naprężeń oraz zaproponowano sposób składania charakterystycznych wartości poszczególnych składowych naprężeń do zastosowania w przepisach Polskiego Rejestru Statków. Sposób ten bazuje na koncepcji...
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Probabilistic limit state analysis of framed structures. The Monte Carlo simulation.
PublikacjaW pracy opisano koncepcję rozkładu prawdopodobieństwa stanu granicznego konstrukcji. Koncepcja ta oparta jest na problemowo zorientowanej procedurze symulacyjnej Monte Carlo. Niezawodnosć lub prawdopodobieństwo awarii układu oblicza się na podstawie rozkładu prawdopodobieństwa stanu granicznego.
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Photoenhanced current as a tool for investigating non-uniform structures of tetracene layer.
PublikacjaPowierzchniowe prądy fotowzmocnione używane były jako narzędzie do badań fizycznych własności powierzchni warstw od strony podłoża, a także od strony przeciwległej podłożu.