Статті в журналах: "Defects Chemistry"

1

Gabániová, Mária. "Surface Chemistry-Based Surface Defects Situated on Steel Strips Edges." Defect and Diffusion Forum 405 (November 2020): 199–204. http://dx.doi.org/10.4028/www.scientific.net/ddf.405.199.

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Two thirds of all examined defect cases present on rolled steel strips appeared to be chemical in nature. They are characterized by a modification in surface chemistry. Chemistry-based defects on the steel strips can vary in composition and generally consist of reaction products with the steel substrate. First big category of widely occurring chemistry-based defects is corrosion or oxidation, second contamination with alien matter and third defect category is related to carbon sediments. A number of different surface chemistry-based defects are related to annealing process. Common problem, that occurs in communication is, that identical defects are often indicated by different names and identical names are given for different defects. In the present study an overview including possible causes of three types of the continuous chemistry-based defects situated on the steel strip edges, that appeared to be the same at first glance, is presented: carbon edge deposit, low reflectivity band and annealed border.

2

Ipser, Herbert. "A3B Intermetallics: Defect chemistry and nonstoichiometry." Pure and Applied Chemistry 79, no. 10 (January 1, 2007): 1675–89. http://dx.doi.org/10.1351/pac200779101675.

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The defect chemistry of different ordered intermetallic compounds with the A3B stoichiometry was investigated. Three groups were distinguished according to their crystal structure: L12 compounds (Ni3Al, Ni3Ga, Pt3Ga, Pt3In), D019 compounds (Ti3Al), and D03 compounds (Fe3Al, Ni3Sb). Statistical-thermodynamic models were derived based on a Wagner-Schottky approach, and the calculated activity curves (thermodynamic activity vs. composition) were compared with experimental activity data. In this way, we attempted to obtain at least estimated values for the energies of formation of the different types of point defects present in the corresponding compound, both as configurational defects (which are responsible for nonstoichiometry) and as thermal defects. In the majority of cases, thermodynamic activities had to be determined experimentally in the present study, using either an emf method with a solid electrolyte (Ni3Ga, Pt3Ga, Pt3In, Fe3Al) or a Knudsen cell-mass spectrometric method (Ni3Sb).

3

Kovalevsky, Andrei V., Myriam H. Aguirre, Sascha Populoh, Sonia G. Patrício, Nuno M. Ferreira, Sergey M. Mikhalev, Duncan P. Fagg, Anke Weidenkaff, and Jorge R. Frade. "Designing strontium titanate-based thermoelectrics: insight into defect chemistry mechanisms." Journal of Materials Chemistry A 5, no. 8 (2017): 3909–22. http://dx.doi.org/10.1039/c6ta09860f.

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The work establishes a closer link between the defect chemistry and thermoelectric properties of strontium titanate-based materials, by uncovering particular roles of various defects in electronic and thermal transport.

4

Meggiolaro, Daniele, Silvia G. Motti, Edoardo Mosconi, Alex J. Barker, James Ball, Carlo Andrea Riccardo Perini, Felix Deschler, Annamaria Petrozza, and Filippo De Angelis. "Iodine chemistry determines the defect tolerance of lead-halide perovskites." Energy & Environmental Science 11, no. 3 (2018): 702–13. http://dx.doi.org/10.1039/c8ee00124c.

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5

Ayoub, Irfan, Vijay Kumar, Reza Abolhassani, Rishabh Sehgal, Vishal Sharma, Rakesh Sehgal, Hendrik C. Swart, and Yogendra Kumar Mishra. "Advances in ZnO: Manipulation of defects for enhancing their technological potentials." Nanotechnology Reviews 11, no. 1 (January 1, 2022): 575–619. http://dx.doi.org/10.1515/ntrev-2022-0035.

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Abstract This review attempts to compile the physics and chemistry of defects in zinc oxide (ZnO), at both, the fundamental and application levels. The defects, either inherent ones or introduced externally, have broadened the ZnO material field in various directions. The ZnO material exhibits many defect-attributed properties leading to broad technological applications: electronic and optoelectronic devices, sensors, optical components, ceramic industry, biomedical, catalysis, lightening, etc. Considering the huge defect-dependent technological scopes, the ZnO material is constantly engineered for various defects, and corresponding functionalities are tailored with respect to particular applications. The functional properties of ZnO are strongly influenced by the defects, and as a result, the defect engineering of the ZnO materials has remained an important motivation in materials science and engineering in terms of localized defects, extended defects, impurities, and surface defects, etc. A detailed characterization of these defects seems to be an essential part of any research area. The correlations of the microstructural characteristics with electrical and optical properties of ZnO are then a natural step for further facilitating an efficient way toward advanced ZnO-based materials and devices. The present review is an effort to shed light on the defects of ZnO, properties, theoretical aspects, and corresponding applications.

6

Götze, Jens, Yuanming Pan, and Axel Müller. "Mineralogy and mineral chemistry of quartz: A review." Mineralogical Magazine 85, no. 5 (September 28, 2021): 639–64. http://dx.doi.org/10.1180/mgm.2021.72.

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AbstractQuartz (trigonal, low-temperature α-quartz) is the most important polymorph of the silica (SiO2) group and one of the purest minerals in the Earth crust. The mineralogy and mineral chemistry of quartz are determined mainly by its defect structure. Certain point defects, dislocations and micro-inclusions can be incorporated into quartz during crystallisation under various thermodynamic conditions and by secondary processes such as alteration, irradiation, diagenesis or metamorphism. The resulting real structure is a fingerprint of the specific physicochemical environment of quartz formation and also determines the quality and applications of SiO2 raw materials. Point defects in quartz can be related to imperfections associated with silicon or oxygen vacancies (intrinsic defects), to different types of displaced atoms, and/or to the incorporation of foreign ions in lattice sites and interstitial positions (extrinsic defects). Due to mismatch in charges and ionic radii only a limited number of ions can substitute for Si4+ in the crystal lattice or can be incorporated in interstitial positions. Therefore, most impurity elements in quartz are present at concentrations below 1 ppm. The structural incorporation in a regular Si4+ lattice site has been proven for Al3+, Ga3+, Fe3+, B3+, Ge4+, Ti4+, P5+ and H+, of which Al3+ is by far the most common and typically the most abundant. Unambiguous detection and characterisation of defect structures in quartz are a technical challenge and can only be successfully realised by a combination of advanced analytical methods such as electron paramagnetic resonance (EPR) spectroscopy, cathodoluminescence (CL) microscopy and spectroscopy as well as spatially resolved trace-element analysis such as laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and secondary-ion mass spectrometry (SIMS). The present paper presents a review of the state-of-the-art knowledge concerning the mineralogy and mineral-chemistry of quartz and illustrates important geological implications of the properties of quartz.

7

Luo, Yang, and Yinghong Wu. "Defect Engineering of Nanomaterials for Catalysis." Nanomaterials 13, no. 6 (March 21, 2023): 1116. http://dx.doi.org/10.3390/nano13061116.

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8

Chiodelli, G., U. Anselmi-Tamburini, M. Arimondi, G. Spinolo, and G. Flor. "Defect Chemistry of “BaCuO2” II. Transport Properties and Nature of Defects." Zeitschrift für Naturforschung A 50, no. 11 (November 1, 1995): 1059–66. http://dx.doi.org/10.1515/zna-1995-1113.

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Abstract The charge transport properties of "BaCuO2" with 88:90 (Ba :Cu) cation ratio were characterized by thermopower, electrical conductivity and ionic transport number measurements in a wide range of temperature and oxygen partial pressure conditions. The nature of carriers is always represented by small polarons due to self-trapping of the electronic holes generated by the oxygen non-stoichiometry equilibrium. Some anomalies in carrier mobility as a function of temperature are shown not to be related to incomplete ionization of oxygen atoms on interstitial sites

9

Withers, Ray, Jeffrey Sellar, Michael O'Keeffe, and Stephen Hyde. "Bruce Godfrey Hyde 1925–2014." Historical Records of Australian Science 26, no. 2 (2015): 179. http://dx.doi.org/10.1071/hr15006.

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Bruce Hyde made seminal contributions to modern solid state chemistry, in particular to the understanding and characterization of non-stoichiometry and structural complexity in the solid state. His work showed unequivocally that non-stoichiometric crystalline materialswere often much more highly ordered than previously believed, that the ‘point defects' of conventional wisdom were in fact ordered into extended defects and that these defects were themselves ordered into structures of complexities hitherto unimagined. His deep understanding of crystal chemistry and structural relationships is apparent in his two co-authored books with his closest colleagues, Sten Andersson and Michael O'Keeffe. It also led to his mentoring an entire generation of younger Australian (and international) solid state chemists.

10

Stemmer, S., G. Duscher, E. M. James, M. Ceh, and N. D. Browning. "Atomic Scale Structure-Property Relationships of Defects and Interfaces in Ceramics." Microscopy and Microanalysis 4, S2 (July 1998): 556–57. http://dx.doi.org/10.1017/s143192760002290x.

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The evaluation of the two dimensional projected atom column positions around a defect or an interface in an electronic ceramic, as it has been performed in numerous examples by (quantitative) conventional high-resolution electron microscopy (HRTEM), is often not sufficient to relate the electronic properties of the material to the structure of the defect. Information about point defects (vacancies, impurity atoms), and chemistry or bonding changes associated with the defect or interface is also required. Such complete characterization is a necessity for atomic scale interfacial or defect engineering to be attained.One instructive example where more than an image is required to understand the structure property relationships, is that of grain boundaries in Fe-doped SrTi03. Here, the different formation energies of point defects cause a charged barrier at the boundary, and a compensating space charge region around it. The sign and magnitude of the barrier depend very sensitively on the atomic scale composition and chemistry of the boundary plane.

11

Wu, Yifeng, Kelsey J. Mirrielees, and Douglas L. Irving. "On native point defects in ZnSe." Applied Physics Letters 120, no. 23 (June 6, 2022): 232102. http://dx.doi.org/10.1063/5.0092736.

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Aiming at a fundamental understanding of the defect chemistry of pure ZnSe for optical and quantum applications, systematic density functional theory calculations with hybrid exchange-correlation functionals were performed to build an accurate database of native defects in ZnSe, including isolated defects and first nearest-neighbor defect–defect complexes. From the defect formation energies, zinc vacancy is found to be the most prevalent defect as the Fermi level approaches the conduction band edge, while zinc interstitial in the selenium tetrahedron and selenium vacancy become the most prevalent defects as the Fermi level approaches the valence band maximum. The divacancy complex, consisting of first nearest-neighboring zinc and selenium vacancies, is also found to have a favorable binding energy across the entire bandgap. Its formation energy is, however, always higher than either the isolated zinc or selenium vacancy, meaning it will never be the predominant defect in equilibrium. Finally, a point defect with extended spin coherence in Fluorine-implanted ZnSe was recently discovered, and it was found to exhibit a broad emission peak centered at 2.28 eV. The identity of this defect was determined to be either zinc vacancy or its associated complex according to the electron paramagnetic resonance measurements. Explicit simulations of the optical signatures of all zinc vacancy-related native defects were conducted here, showing that both zinc vacancy and divacancy are the most likely native defect contributors to that peak.

12

Zhao, Xiaoji, Yanlu Li, and Xian Zhao. "Density Functional Theory Study of the Point Defects on KDP (100) and (101) Surfaces." Molecules 27, no. 24 (December 17, 2022): 9014. http://dx.doi.org/10.3390/molecules27249014.

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Surface defects are usually associated with the formation of other forms of expansion defects in crystals, which have an impact on the crystals’ growth quality and optical properties. Thereby, the structure, stability, and electronic structure of the hydrogen and oxygen vacancy defects (VH and VO) on the (100) and (101) growth surfaces of KDP crystals were studied by using density functional theory. The effects of acidic and alkaline environments on the structure and properties of surface defects were also discussed. It has been found that the considered vacancy defects have different properties on the (100) and (101) surfaces, especially those that have been reported in the bulk KDP crystals. The (100) surface has a strong tolerance for surface VH and VO defects, while the VO defect causes a large lattice relaxation on the (101) surface and introduces a deep defect level in the band gap, which damages the optical properties of KDP crystals. In addition, the results show that the acidic environment is conducive to the repair of the VH defects on the surface and can eliminate the defect states introduced by the surface VO defects, which is conducive to improving the quality of the crystal surface and reducing the defect density. Our study opens up a new way to understand the structure and properties of surface defects in KDP crystals, which are different from the bulk phase, and also provides a theoretical basis for experimentally regulating the surface defects in KDP crystals through an acidic environment.

13

Zhou, X., J. R. Mianroodi, A. Kwiatkowski da Silva, T. Koenig, G. B. Thompson, P. Shanthraj, D. Ponge, B. Gault, B. Svendsen, and D. Raabe. "The hidden structure dependence of the chemical life of dislocations." Science Advances 7, no. 16 (April 2021): eabf0563. http://dx.doi.org/10.1126/sciadv.abf0563.

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Dislocations are one-dimensional defects in crystals, enabling their deformation, mechanical response, and transport properties. Less well known is their influence on material chemistry. The severe lattice distortion at these defects drives solute segregation to them, resulting in strong, localized spatial variations in chemistry that determine microstructure and material behavior. Recent advances in atomic-scale characterization methods have made it possible to quantitatively resolve defect types and segregation chemistry. As shown here for a Pt-Au model alloy, we observe a wide range of defect-specific solute (Au) decoration patterns of much greater variety and complexity than expected from the Cottrell cloud picture. The solute decoration of the dislocations can be up to half an order of magnitude higher than expected from classical theory, and the differences are determined by their structure, mutual alignment, and distortion field. This opens up pathways to use dislocations for the compositional and structural nanoscale design of advanced materials.

14

Duan, Wei, Guangzhi Guo, Guozhu Zhu, Xuefeng Zhao, Lu Pu, Zeli Ju, Haofei Sun, and Jian Gao. "Chemical Defects and Impurities Introduce Charge Traps to Silicone Rubber: a Quantum Chemistry Study." Journal of Physics: Conference Series 2404, no. 1 (December 1, 2022): 012005. http://dx.doi.org/10.1088/1742-6596/2404/1/012005.

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Abstract The distributions of charge trap energy levels in polymer insulation material have an important influence on the charge transport characteristics and breakdown field strength of the polymer insulation, which thus has attracted considerable attention. Based on the quantum chemistry calculations, the characteristics of charge traps induced by different chemical defects and additives in silicone rubber materials are investigated. The projected density of states, and frontier molecular orbital distribution of defective silicone rubber and additive molecules are analyzed. The carbonyl defect, carboxyl defect and diethyl maleate additive all introduce deep electron traps (more than 1eV) in PDMS materials. The carbonyl defect and KH550 additive introduce shallow hole traps (less than 1eV) in PDMS materials. If chemical defects have a dominant contribution to the frontier molecular orbital of polymer is the key factor of whether they can introduce charge traps.

15

Schmid, Alexander, Ghislain M. Rupp та Jürgen Fleig. "Voltage and partial pressure dependent defect chemistry in (La,Sr)FeO3−δ thin films investigated by chemical capacitance measurements". Physical Chemistry Chemical Physics 20, № 17 (2018): 12016–26. http://dx.doi.org/10.1039/c7cp07845e.

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Chemical capacitance measurements are used to study the defect chemistry of La_0.6Sr_0.4FeO_3−δ thin films and their polarization (η) and p_O2 dependence. Important point defects are oxygen vacancies (), electrons (e′) and holes (h˙).

16

Hoang, Khang, and Michelle D. Johannes. "Defect chemistry in layered transition-metal oxides from screened hybrid density functional calculations." J. Mater. Chem. A 2, no. 15 (2014): 5224–35. http://dx.doi.org/10.1039/c4ta00673a.

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First-principles studies of the thermodynamics and transport of intrinsic point defects provide guidelines for defect-controlled synthesis and shed light on the electronic and ionic conduction mechanisms in LiCoO₂ and LiNiO₂.

17

Hong, Terence Zhi Xiang, Liming You, Madhavi Dahanayaka, Adrian Wing-Keung Law, and Kun Zhou. "Influence of Substitutional Defects in ZIF-8 Membranes on Reverse Osmosis Desalination: A Molecular Dynamics Study." Molecules 26, no. 11 (June 3, 2021): 3392. http://dx.doi.org/10.3390/molecules26113392.

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In this study, molecular dynamics simulation is used to investigate the effects of water-based substitutional defects in zeolitic imidazolate frameworks (ZIF)-8 membranes on their reverse osmosis (RO) desalination performance. ZIF-8 unit cells containing up to three defect sites are used to construct the membranes. These substitutional defects can either be Zn defects or linker defects. The RO desalination performance of the membranes is assessed in terms of the water flux and ion rejection rate. The effects of defects on the interactions between the ZIF-8 membranes and NaCl are investigated and explained with respect to the radial distribution function (RDF) and ion density distribution. The results show that ion adsorption on the membranes occurs at either the nitrogen atoms or the defect sites. Complete NaCl rejection can be achieved by introducing defects to change the size of the pores. It has also been discovered that the presence of linker defects increases membrane hydrophilicity. Overall, molecular dynamics simulations have been used in this study to show that water-based substitutional defects in a ZIF-8 structure reduce the water flux and influence its hydrophilicity and ion adsorption performance, which is useful in predicting the type and number of defect sites per unit cell required for RO applications. Of the seven ZIF-8 structures tested, pristine ZIF-8 exhibits the best RO desalination performance.

18

Wei, Bing, Lei Gao, Xue-song Tang, and Kuangrong Hao. "Multi-Class Object Learning with Application to Fabric Defects Detection." AATCC Journal of Research 8, no. 1_suppl (September 2021): 165–72. http://dx.doi.org/10.14504/ajr.8.s1.20.

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Deep convolutional neural networks (CNNs) have shown great success in single-class fabric image detection. However, real-world fabric defect images generally contain several types of defects in one image. Accurately recognizing and classifying multi-class fabric defect images is still an unsolved issue due to the complexity of intersected defects, as well as difficulty in distinguishing small-size defects. To address these challenges, this study develops a methodology based on the deep learning feature pyramid networks (FPN) approach to detect multi-class fabric defects. To evaluate the proposed detection model, we built a unique multi-class fabric defects database (DHU-MO1000), where multi-class defect images are generated by industrial monitors from a textile factory. We used the dataset as the benchmark for multi-class defects detection training and testing the FPN. Furthermore, we conducted extensive experimental validations for various design choices. The experimental results show that the model outperformed existing multi-class object detection methods.

19

Todorova, Mira, and Jörg Neugebauer. "Identification of bulk oxide defects in an electrochemical environment." Faraday Discussions 180 (2015): 97–112. http://dx.doi.org/10.1039/c4fd00238e.

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We discuss how electronic-structure calculations can be used to identify the dominant point defects that control the growth and dissolution of the oxide barrier layer formed if a metal comes into contact with a corrosive environment. Using the example of the Zn/ZnO/H₂O interface we develop and apply a theoretical approach that is firmly based onab initiocomputed defect formation energies and that unifies concepts of semiconductor defect chemistry with electrochemical concepts. Employing this approach we find that the commonly invoked and chemically intuitive defects such as the doubly negatively charged oxygen vacancy in electrochemically formed ZnO films may not be present. Rather, hitherto not discussed defects such as the oxygen interstitial or unexpected charge states, such as the neutral oxygen vacancy, are found. These new defect types will be shown to critically impact our understanding of fundamental corrosion mechanisms and to provide new insight into strategies to develop alloys with higher corrosion resistance.

20

Chen, Yue, Xuehao Pan, and Lingfang Deng. "Study on the Localization of Defects in Typical Steel Butt Welds Considering the Effect of Residual Stress." Applied Sciences 13, no. 4 (February 18, 2023): 2648. http://dx.doi.org/10.3390/app13042648.

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When using magnetic memory detection technology to locate weld cracks and porous defects, the traditional zero-point polarity theory leads to misjudgments in defect location and difficulty in distinguishing between the residual stress and the magnetic signals generated by defects due to the influence of external noise and residual stress. Therefore, this paper considers the different mechanisms of magnetic signal generation in areas where crack- and porosity-type defects and residual stresses are located and discusses research focused on the detection of weld defect localization considering the influence of residual stresses. Using the mechanism of magnetic signal generation as a starting point, the three-dimensional magnetic modulus gradient polarity determination method is proposed to distinguish residual stress and defects’ magnetic signals. Through the COMSOL simulation of a welding defect’s finite element magnetic signal, the resulting magnetic signal is converted into a characteristic determination formula for characterization. To verify the accuracy of the simulated characterization, the 3D magnetic signal is extracted and verified manually. Finally, a double orthogonal wavelet transform is introduced to eliminate the random noise in the gradient of the three-dimensional magnetic modulus. The results show that the theoretical analysis, numerical simulation, and experimental results agree with each other. The three-dimensional magnetic modulus gradient values of cracks and pores are much higher than that of the defect-free residual stress area. The three-dimensional magnetic gradient modulus can locate defects and characterize the lengths of defects. The dual orthogonal wavelet eliminates noise interference while improving the accuracy of locating three-dimensional magnetic modulus gradient defects.

21

Chen, Huajie, Faizan Q. Nazar, and Christoph Ortner. "Geometry equilibration of crystalline defects in quantum and atomistic descriptions." Mathematical Models and Methods in Applied Sciences 29, no. 03 (March 2019): 419–92. http://dx.doi.org/10.1142/s0218202519500131.

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We develop a rigorous framework for modeling the geometry equilibration of crystalline defects. We formulate the equilibration of crystal defects as a variational problem on a discrete energy space and establish qualitatively sharp far-field decay estimates for the equilibrium configuration. This work extends [V. Ehrlacher, C. Ortner and A. Shapeev, Analysis of boundary conditions for crystal defect atomistic simulations, Arch. Ration. Mech. Anal. 222 (2016) 1217–1268] by admitting infinite-range interaction which in particular includes some quantum chemistry based interatomic interactions.

22

Costan, Victor Vlad, Otilia Boisteanu, Daniel Timofte, and Marius Dabija. "The Value of Titanium Mesh in Cranio-Maxillofacial Reconstructive Surgery." Revista de Chimie 70, no. 8 (September 15, 2019): 3021–23. http://dx.doi.org/10.37358/rc.19.8.7478.

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Cranio-maxillofacial defects are often challenging to reconstruct due to the difficulty of selecting the most appropriate material for the individual case while ensuring good outcomes with minimal complications. The chemical properties of titanium regarding biocompatibility coupled with the physical properties of the mesh design, make titanium mesh an optimal material that is increasingly used in reconstructive surgery. We present our experience regarding the use of titanium mesh for the reconstruction of 14 cranio-maxillofacial bone defects of various etiologies, including 8 defects following oncologic resection, 4 posttraumatic sequelae defects, one osteofascial flap donor site defect and one defect following treatment for osteomyelitis. The advantages and disadvantages of this reconstructive method are discussed.

23

Su, Juan, Xiaoxin Zou, and Jie-Sheng Chen. "Self-modification of titanium dioxide materials by Ti3+ and/or oxygen vacancies: new insights into defect chemistry of metal oxides." RSC Adv. 4, no. 27 (2014): 13979–88. http://dx.doi.org/10.1039/c3ra47757f.

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In this review, we highlight the recent research efforts towards understanding the defect chemistry of titanium dioxide. Particular attention is paid to the synthesis of self-modified TiO₂ materials with Ti³⁺/oxygen vacancies and the favorable effects of these defects on the properties and applications of the obtained materials.

24

Hyde, B., and A. Mclaren. "The Crystal Chemistry of Moganite and Amethyst." Australian Journal of Chemistry 49, no. 8 (1996): 861. http://dx.doi.org/10.1071/ch9960861.

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The crystal structure of moganite , SiO2, is described, analysed, and shown to be (mimetic) Brazil-twinned α-quartz: it consists of {1101} layers of the latter, one tetrahedron thick, coherently joined at composition planes, with left- and right-handed quartz layers alternating. The structure of the region immediately adjacent to a composition plane is identical to that found in macroscopically twinned quartz, e.g. in amethyst. Thus the 'defect' structure in the latter is the total structure of the former-a classic example of Wadsley's idea that, in crystals, 'defects' are stable structural entities.

25

Polfus, Jonathan M., Tor S. Bjørheim, Truls Norby, and Rune Bredesen. "Surface defect chemistry of Y-substituted and hydrated BaZrO3 with subsurface space-charge regions." Journal of Materials Chemistry A 4, no. 19 (2016): 7437–44. http://dx.doi.org/10.1039/c6ta02067d.

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First-principles calculations were utilized to elucidate the complete defect equilibria of surfaces of proton conducting BaZrO₃, encompassing charged species adsorbed to the surface, defects in the surface layer as well as in the subsurface space-charge region and bulk.

26

Wales, David J. "Chemistry, Geometry, and Defects in Two Dimensions." ACS Nano 8, no. 2 (February 13, 2014): 1081–85. http://dx.doi.org/10.1021/nn500645r.

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27

Von Bardeleben, H. J. "The chemistry of structural defects in CuInSe2." Solar Cells 16 (January 1986): 381–90. http://dx.doi.org/10.1016/0379-6787(86)90098-0.

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28

Hoskins, BF, and RL Martin. "The Structures of Higher Rare Earth Oxides: Role of the Coordination Defect." Australian Journal of Chemistry 48, no. 4 (1995): 709. http://dx.doi.org/10.1071/ch9950709.

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A milestone in our understanding of the chemistry of the defect solid state has been achieved through new insights provided by recently published neutron diffraction studies of five rare earth oxides with compositions in the range M2O3-MO2. For more than four decades the exact way by which gross concentrations (i.e., up to 25%) of vacant sites can be accommodated in the fluorite MO2 lattice has remained largely unresolved. There is now compelling evidence that the vacancies do not exist in isolation but as octahedral 'coordination defects' of composition {MIII/2MIV/1.5□O6}. It is now clear that the intricate planar patterns formed by anion vacancies in the fluorite lattice arise from the unique and structure-determining topology of these coordination defects. The decisive role played by the coordination defect in generating extended defects in these fluorite-related oxides is highlighted in this paper.

29

Jangizehi, Amir, Friederike Schmid, Pol Besenius, Kurt Kremer, and Sebastian Seiffert. "Defects and defect engineering in Soft Matter." Soft Matter 16, no. 48 (2020): 10809–59. http://dx.doi.org/10.1039/d0sm01371d.

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30

Fu, Xiaqing, Zirui Qiao, Hangyu Zhou, and Dan Xie. "Defect Engineering in Transition Metal Dichalcogenide-Based Gas Sensors." Chemosensors 12, no. 6 (May 21, 2024): 85. http://dx.doi.org/10.3390/chemosensors12060085.

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Since the discovery of innovative two-dimensional (2D) materials, significant efforts have been dedicated to exploring their intriguing properties and emerging applications. Among all candidates, transition metal dichalcogenides (TMDs) have proven to be exceptional for gas sensing, while defects engineering has been introduced to modify the pristine TMDs for better gas sensing performances. In this review, we systematically summarize types of defects, advanced characterization techniques, and state-of-the-art controllable synthetic methods. Various types of defects in TMDs can induce diverse changes in chemical and electron structures, which are closely correlated with gas sensing ability. Therefore, connections between defects and gas sensing mechanisms and performances have been addressed based on both defect categories and electron affinity of gases. This review will be a guide for researchers in defective materials and open up the field of precisely synthesis chemistry and deepen the understanding of the underlying effects of defects in other 2D materials.

31

Mo, Dongmei, and Wai Keung Wong. "Fabric Defect Classification based on Deep Hashing Learning." AATCC Journal of Research 8, no. 1_suppl (September 2021): 191–201. http://dx.doi.org/10.14504/ajr.8.s1.23.

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Classifying categories of fabric defects can greatly help to identify the source of causing fabric defects in the textile manufacturing process. Most existing artificial intelligence based methods focus on identifying and locating defective regions and do not analyze the categories of the defects. On the other hand, as current fabric defect detection methods depend on handcrafted features, they can only handle fabric with specific patterns or textures. In this paper, we propose a novel model which can learn high-level representation from the automatic observations of the input images that can recognize the categories of the defects for various fabric patterns and textures, instead of only locating defects on specific patterns. Experimental results show that the proposed method is superior to the state-of-the-art deep hash methods in terms of fabric defect classification.

32

Liu, Wei, Yaning Han, Min Liu, Liang Chen, and Jing Xu. "Effect of defects on optical and electronic properties of graphene quantum dots: a density functional theory study." RSC Advances 13, no. 24 (2023): 16232–40. http://dx.doi.org/10.1039/d3ra02564k.

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The effects of different types of defects (vacancy, Stone–Wales defects, and heteroatom doping) and varying defect concentrations (single and double defects) on the structure, electronic, and optical properties of graphene quantum dots (GQDs).

33

Chen, Kunfeng, Yanlu Li, Chao Peng, Zheng Lu, Xingyun Luo, and Dongfeng Xue. "Microstructure and defect characteristics of lithium niobate with different Li concentrations." Inorganic Chemistry Frontiers 8, no. 17 (2021): 4006–13. http://dx.doi.org/10.1039/d1qi00562f.

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Li vacancies and Nb antisites are stable point defects in congruent lithium niobate. The intrinsic point defects induce the Li/Nb cation mixing, the formation of temperature-dependent defect microstructures, and disorder within the LiNbO3 lattice frame.

34

Noh, JungHyun, and Jan P. F. Lagerwall. "Topological Defect-Guided Regular Stacking of Focal Conic Domains in Hybrid-Aligned Smectic Liquid Crystal Shells." Crystals 11, no. 8 (August 4, 2021): 913. http://dx.doi.org/10.3390/cryst11080913.

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We study liquid crystal (LC) shells in hybrid configuration (director tangential to the inside but normal to the outside) as they slowly undergo a transition from a nematic (N) to a smectic-A (SmA) phase. Every shell has two antipodal +1 topological defects, at the thinnest and thickest points, respectively. On cooling from N to SmA, the symmetry axis connecting the defects gradually reorients from along gravity to perpendicular to it, reversibly and continuously, if the LC and aqueous phase are density matched at the N-SmA transition. This suggests reduced density near the defects—reflecting a local reduction in order—under the strong confinement with antagonistic boundary conditions. In the SmA phase, a regular array of focal conic domains (FCDs) develops, templated in position and orientation by the +1 defect at the thinnest point. Around this defect, a single complete toroidal FCD always develops, surrounded by incomplete FCDs. In contrast to similar FCD arrangements on flat aqueous interfaces, this is a stable situation, since the two +1 defects are required by the spherical topology. Our results demonstrate how the topological defects of LC shells can be used to template complex self-organized structures. With a suitable adaption of the LC chemistry, shells might serve as a basis for producing solid particles with complex yet highly regular morphologies.

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Liu, Jinxin, and Kexin Li. "Intelligent Metal Welding Defect Detection Model on Improved FAST-PNN." Coatings 12, no. 10 (October 11, 2022): 1523. http://dx.doi.org/10.3390/coatings12101523.

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In order to solve the problem of accurate and efficient detection of welding defects in the process of batch welding of metal parts, an improved Probabilistic Neural Network (PNN) algorithm was proposed to build an automatic identification model of welding defects. Combined with the characteristics of the PNN model, the structure and algorithm flow of the FAST-PNN algorithm model are proposed. Extraction of welding defect image texture features of metal welded parts by a Gray Level Co-occurrence Matrix (GLCM) screens out the characteristic indicators that can effectively characterize welding defects. Weld defect texture features are used as input to build a defect classification model with FAST-PNN, for accurate and efficient classification of welding defects. The results show that the improved FAST-PNN model can effectively identify the types of welding defects such as burn-through, pores and cracks, etc. The classification recognition accuracy and recognition efficiency have been significantly improved. The proposed defect welding identification method can accurately and effectively identify the damage types of welding defects based on a small number of defect sample images. Welding defects can be quickly identified and classified by simply collecting weld images, which helps to solve the problem of intelligent, high-precision, fast real-time online detection of welding defects in modern metal structures; it provides corresponding evidence for formulating response strategies, with a certain theoretical basis and numerical reference.

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Settele, Simon, and Jana Zaumseil. "New Synthetic Routes to Introduce Sp ³-Defects in Carbon Nanotubes with a Variety of Functional Groups." ECS Meeting Abstracts MA2022-01, no. 9 (July 7, 2022): 728. http://dx.doi.org/10.1149/ma2022-019728mtgabs.

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The controlled functionalization of single-walled carbon nanotubes (SWNTs) with luminescent sp 3-defects has emerged as a powerful tool to enhance their usually low photoluminescence quantum yields and has created the potential to employ them for bioimaging and optical sensors. For that, it is necessary to match and adapt the substituents of the sp 3-defects to the desired application. To attach a large variety of complex substituents to sp 3-defects an universal approach is required. Here, we introduce sp 3-defects to polymer-wrapped (6,5) SWNTs via diazonium salt chemistry [ACS Nano 2021, 15, 5147–5157] bearing an alkyne moiety and subsequently add the desired substituent by click-chemistry. This opens up the possibility to introduce many different functional groups such as stable organic radicals, photosensitizers or fluorophores, which are already available for click-reactions. This approach is not limited to E11* defects introduced by diazonium chemistry, but can be further extended to more red-shifted E11*− defects [Nat. Commun. 2021, 12, 2119].

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Carraro, Giovanni, Letizia Savio, and Luca Vattuone. "Influence of Defects and Heteroatoms on the Chemical Properties of Supported Graphene Layers." Coatings 12, no. 3 (March 17, 2022): 397. http://dx.doi.org/10.3390/coatings12030397.

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A large and growing number of theoretical papers report the possible role of defects and heteroatoms on the chemical properties of single-layer graphene. Indeed, they are expected to modify the electronic structure of the graphene film, allow for chemisorption of different species, and enable more effective functionalisation. Therefore, from theoretical studies, we get the suggestion that single and double vacancies, Stone–Wales defects and heteroatoms are suitable candidates to turn nearly chemically inert graphene into an active player in chemistry, catalysis, and sensoristics. Despite these encouraging premises, experimental proofs of an enhanced reactivity of defected/doped graphene are limited because experimental studies addressing adsorption on well-defined defects and heteroatoms in graphene layers are much less abundant than theoretical ones. In this paper, we review the state of the art of experimental findings on adsorption on graphene defects and heteroatoms, covering different topics such as the role of vacancies on adsorption of oxygen and carbon monoxide, the effect of the presence of N heteroatoms on adsorption and intercalation underneath graphene monolayers, and the role of defects in covalent functionalisation and defect-induced gas adsorption on graphene transistors.

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CHIODELLI, G., U. ANSELMI-TAMBURINI, M. ARIMONDI, G. SPINOLO, and G. FLOR. "ChemInform Abstract: Defect Chemistry of “BaCuO2”. Part II. Transport Properties and Nature of Defects." ChemInform 27, no. 14 (August 12, 2010): no. http://dx.doi.org/10.1002/chin.199614012.

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Azzaz, Hamza, Djaffar Dahmoun, O. Chaterbache, and Mohammed Azzaz. "Prediction of Mechanical Properties of Coiled Carbon Nanotubes by Molecular Structural Mechanics Based Finite Element Modelling." Defect and Diffusion Forum 380 (November 2017): 124–34. http://dx.doi.org/10.4028/www.scientific.net/ddf.380.124.

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Carbon nanotubes (NTC) have very spectacular mechanical properties related to their nanometric structure, their perfect arrangement and their one-dimensional geometry. As with all materials, structural defects are inevitable and affects NTC properties. Among these defects, we distinguish the topological defects, the dislocations and the penta-hepta defect. But the presence of these defects is not totally harmful, because the existence of some structure like the coiled nanotube is the result of these defects. For this, in the first part of this work, the coiled carbon nanotube structure is studied, a method for the designing of this structure is proposed, the geometric parameters are detailed and the structural coefficients are determined. Therefore, a procedure for moving from a graphene sheet to a coiled nanotube is developed. Then, the second part of this study represents an attempt to calculate the spring constants of the spiral carbon nanotube. Mechanical properties of this material are investigated by means of molecular structural mechanics (MSM) method in ANSYS finite element code. The model serves as a link between the computational chemistry and the solid mechanics by substituting discrete molecular structures, with an equivalent-structural model. A coiled carbon nanotube has been modeled on the nanoscale by one-dimensional elements (3D beam). The results show a considerable influence of structural parameters (diameter, chirality, pitch and defect position) on the coiled nanotube mechanical properties.

40

Wang, Xianju, Shanhui Liu, Han Zhang, Yinfeng Li, and Huiran Ren. "Defects Detection of Lithium-Ion Battery Electrode Coatings Based on Background Reconstruction and Improved Canny Algorithm." Coatings 14, no. 4 (March 27, 2024): 392. http://dx.doi.org/10.3390/coatings14040392.

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Aiming to address the problems of uneven brightness and small defects of low contrast on the surface of lithium-ion battery electrode (LIBE) coatings, this study proposes a defect detection method that combines background reconstruction with an enhanced Canny algorithm. Firstly, we acquire and pre-process the electrode coating image, considering the characteristics of the electrode coating process and defects. Secondly, background reconstruction and the difference method are introduced to achieve the rough localization of coating defects. Furthermore, the image with potential defects undergoes enhancement through improved Gamma correction, and the PSO-OTSU algorithm with adaptive searching is applied to determine the optimal segmentation. Finally, precise defect detection is accomplished using the improved Canny algorithm and morphological processing. The experimental results show that, compared with the maximum entropy method, the region growth method, and the traditional Canny algorithm, the algorithm in this paper has a higher segmentation accuracy for defects. It better retains defect edge features and provides a more accurate detection effect for defects like scratches, dark spots, bright spots, metal leakage, and decarburization, which are difficult to recognize on the background of coating areas of electrodes. The proposed method is suitable for the online real-time defect detection of LIBE coating defects in actual lithium-ion battery industrial production.

41

Forde, Aaron, Erik Hobbie, and Dmitri Kilin. "Role of Pb2+ Adsorbents on the Opto-Electronic Properties of a CsPbBr3 Nanocrystal: A DFT Study." MRS Advances 4, no. 36 (2019): 1981–88. http://dx.doi.org/10.1557/adv.2019.268.

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ABSTRACTFully inorganic lead halide perovskite nanocrystals (NCs) are of interest for photovoltaic and light emitting devices due to optoelectronic properties. Understanding the surface chemistry of these materials is of importance as surface defects can introduce trap-states which reduce their functionality. Here we use Density Functional Theory (DFT) to model surface defects introduced by Pb2+ on a CsPbBr3 NC atomistic model. Two types of defects are studied: (i) an under-coordinated Pb2+ surface atom and (ii) Pb2+ atomic or molecular adsorbents to the NC surface. From the DFT calculations we compute the density of states (DOS) and absorption spectra of the defect models to the pristine fully-passivated NC model. We observe that for the low surface defect regime explored here that neither (i) or (ii) produce trap-states inside of the bandgap and exhibit bright optical absorption for the lowest energy transition. From the models studied, it was found that the Pb2+ atomic absorbent provides broadening of the conduction band edge, which implies chemisorption of Pb2+ to the NC surface. At higher defect densities it would be expected that Pb2+ atomic absorbents would introduce trap-states and degrade the opto-electronic properties of these materials.

42

Dong, Yukun, Li Zhang, Shanchen Pang, Wenjing Yin, Mengying Wu, Meng Wu, and Haojie Li. "Automatic Repair of Semantic Defects Using Restraint Mechanisms." Symmetry 12, no. 9 (September 22, 2020): 1563. http://dx.doi.org/10.3390/sym12091563.

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Recently, software, especially CPS and Internet of Things (IoT), increasingly have high requirements for quality, while program defects exist inevitably duo to the high complexity. Program defect repair faces serious challenges in that such repairs require considerable manpower, and the existing automatic repair approaches have difficulty generating correct patches efficiently. This paper proposes an automatic method for repairing semantic defects in Java programs based on restricted sets which refer to the interval domains of related variables that can trigger program semantic defects. Our work introduces a repair mechanism symmetrically combining defect patterns and repair templates. First, the program semantic defects are summarized into defect patterns according to their grammar and semantic features. A repair template for each type of defect pattern is predefined based on a restricted-set. Then, for each specific defect, a patch statement is automatically synthesized according to the repair template, and the detected defect information is reported by the static detection tool (DTSJava). Next, the patch location is determined by the def-use chain of defect-related variables. Finally, we evaluate the patches generated by our method using DTSJava. We implemented the method in the defect automatic repair prototype tool DTSFix to verify the effect of repairing the semantic defects detected by DTSJava in 6 Java open-source projects. The experimental results showed that 109 of 129 program semantic defects were repaired.

43

Zhao, Yuhong, Jinzhong Tian, Guoning Bai, Leting Zhang, and Hua Hou. "First Principles Study on the Thermodynamic and Elastic Mechanical Stability of Mg2X (X = Si,Ge) Intermetallics with (anti) Vacancy Point Defects." Crystals 10, no. 3 (March 23, 2020): 234. http://dx.doi.org/10.3390/cryst10030234.

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In this paper, based on the density functional theory, through thermodynamic and mechanical stability criteria, the crystal cell model of intermetallic compounds with vacancy and anti-site point defects is constructed and the lattice constant, formation heat, binding energy, elastic constant, and elastic modulus of Mg2X (X = Si, Ge) intermetallics with or without point defects are calculated. The results show that the difference in the atomic radius leads to the instability and distortion of crystal cells with point defects; Mg2X are easier to form vacancy defects than anti-site defects on the X (X = Si, Ge) lattice site, and form anti-site defects on the Mg lattice site. Generally, the point defect is more likely to appear at the Mg position than at the Si or Ge position. Among the four kinds of point defects, the anti-site defect x M g is the easiest to form. The structure of intermetallics without defects is more stable than that with defects, and the structure of the intermetallics with point defects at the Mg position is more stable than that at the Si/Ge position. The anti-site and vacancy defects will reduce the material’s resistance to volume deformation shear strain, and positive elastic deformation, and increase the mechanical instability of the elastic deformation of the material. Compared with the anti-site point defect, the void point defect can lead to the mechanical instability of the transverse deformation of the material and improve the plasticity of the material. The research in this paper is helpful for the analysis of the mechanical stability of the elastic deformation of Mg2X (X = Si, Ge) intermetallics under the service condition that it is easy to produce vacancy and anti-site defects.

44

Petrovova, Eva, Marek Tomco, Katarina Holovska, Jan Danko, Lenka Kresakova, Katarina Vdoviakova, Veronika Simaiova, et al. "PHB/CHIT Scaffold as a Promising Biopolymer in the Treatment of Osteochondral Defects—An Experimental Animal Study." Polymers 13, no. 8 (April 11, 2021): 1232. http://dx.doi.org/10.3390/polym13081232.

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Biopolymer composites allow the creation of an optimal environment for the regeneration of chondral and osteochondral defects of articular cartilage, where natural regeneration potential is limited. In this experimental study, we used the sheep animal model for the creation of knee cartilage defects. In the medial part of the trochlea and on the medial condyle of the femur, we created artificial defects (6 × 3 mm2) with microfractures. In four experimental sheep, both defects were subsequently filled with the porous acellular polyhydroxybutyrate/chitosan (PHB/CHIT)-based implant. Two sheep had untreated defects. We evaluated the quality of the newly formed tissue in the femoral trochlea defect site using imaging (X-ray, Computer Tomography (CT), Magnetic Resonance Imaging (MRI)), macroscopic, and histological methods. Macroscopically, the surface of the treated regenerate corresponded to the niveau of the surrounding cartilage. X-ray examination 6 months after the implantation confirmed the restoration of the contour in the subchondral calcified layer and the advanced rate of bone tissue integration. The CT scan revealed a low regenerative potential in the bone zone of the defect compared to the cartilage zone. The percentage change in cartilage density at the defect site was not significantly different to the reference area (0.06–6.4%). MRI examination revealed that the healing osteochondral defect was comparable to the intact cartilage signal on the surface of the defect. Hyaline-like cartilage was observed in most of the treated animals, except for one, where the defect was repaired with fibrocartilage. Thus, the acellular, chitosan-based biomaterial is a promising biopolymer composite for the treatment of chondral and osteochondral defects of traumatic character. It has potential for further clinical testing in the orthopedic field, primarily with the combination of supporting factors.

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Giacomello, Alberto, Lothar Schimmele, and Siegfried Dietrich. "Wetting hysteresis induced by nanodefects." Proceedings of the National Academy of Sciences 113, no. 3 (December 31, 2015): E262—E271. http://dx.doi.org/10.1073/pnas.1513942113.

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Wetting of actual surfaces involves diverse hysteretic phenomena stemming from ever-present imperfections. Here, we clarify the origin of wetting hysteresis for a liquid front advancing or receding across an isolated defect of nanometric size. Various kinds of chemical and topographical nanodefects, which represent salient features of actual heterogeneous surfaces, are investigated. The most probable wetting path across surface heterogeneities is identified by combining, within an innovative approach, microscopic classical density functional theory and the string method devised for the study of rare events. The computed rugged free-energy landscape demonstrates that hysteresis emerges as a consequence of metastable pinning of the liquid front at the defects; the barriers for thermally activated defect crossing, the pinning force, and hysteresis are quantified and related to the geometry and chemistry of the defects allowing for the occurrence of nanoscopic effects. The main result of our calculations is that even weak nanoscale defects, which are difficult to characterize in generic microfluidic experiments, can be the source of a plethora of hysteretical phenomena, including the pinning of nanobubbles.

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Sloppy, J., J. Idrobo, S. Sundaram, S. Spurgeon, C. Winkler, N. Valanoor, P. Munroe, and M. Taheri. "Interfacial Chemistry, Defects, and Strain in Multiferroic Heterostructures." Microscopy and Microanalysis 17, S2 (July 2011): 1382–83. http://dx.doi.org/10.1017/s1431927611007781.

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47

Sánchez, Ramiro, Elísabet Martín-Tornero, Jesús Lozano, Emanuele Boselli, Patricia Arroyo, Félix Meléndez, and Daniel Martín-Vertedor. "E-Nose Discrimination of Abnormal Fermentations in Spanish-Style Green Olives." Molecules 26, no. 17 (September 2, 2021): 5353. http://dx.doi.org/10.3390/molecules26175353.

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Current legislation in Spain indicates that table olives must be free of off-odors and off-flavors and without symptoms of ongoing alteration or abnormal fermentations. In this regard, the International Olive Council (IOC) has developed a protocol for the sensory classification of table olives according to the intensity of the predominantly perceived defect (PPD). An electronic nose (e-nose) was used to assess the abnormal fermentation defects of Spanish-style table olives that were previously classified by a tasting panel according to the IOC protocol, namely zapateria, butyric, putrid, and musty or humidity. When olives with different defects were mixed, the putrid defect had the greatest sensory impact on the others, while the butyric defect had the least sensory dominance. A total of 49 volatile compounds were identified by gas chromatography, and each defect was characterized by a specific profile. The e-nose data were analyzed using principal component analysis (PCA) and partial least square discriminant analysis (PLS-DA). The different defects were clearly separated from each other and from the control treatment, independently of PPD intensity. Moreover, the e-nose differentiated control olives from table olives with combined sensory defects despite the dilution effect resulting from the combination. These results demonstrate that e-nose can be used as an olfactory sensor for the organoleptic classification of table olives and can successfully support the tasting panel.

48

Wu, J., L. P. Li, W. T. P. Espinosa та S. M. Haile. "Defect chemistry and transport properties of BaxCe0.85M0.15O3-δ". Journal of Materials Research 19, № 8 (серпень 2004): 2366–76. http://dx.doi.org/10.1557/jmr.2004.0302.

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The site-incorporation mechanism of M3+ dopants into A2+B4+O3 perovskites controls the overall defect chemistry and thus their transport properties. For charge-balance reasons, incorporation onto the A2+-site would require the creation of negatively charged point defects (such as cation vacancies), whereas incorporation onto the B4+-site is accompanied by the generation of positively charged defects, typically oxygen vacancies. Oxygen-vacancy content, in turn, is relevant to proton-conducting oxides in which protons are introduced via the dissolution of hydroxyl ions at vacant oxygen sites. We propose here, on the basis of x-ray powder diffraction studies, electron microscopy, chemical analysis, thermal gravimetric analysis, and alternating current impedance spectroscopy, that nominally B-site doped barium cerate can exhibit dopant partitioning as a consequence of barium evaporation at elevated temperatures. Such partitioning and the presence of significant dopant concentrations on the A-site negatively impact proton conductivity. Specific materials examined are BaxCe0.85M0.15O3-δ (x = 0.85 - 1.20; M = Nd, Gd, Yb). The compositional limits for the maximum A-site incorporation are experimentally determined to be: (Ba0.919Nd0.081)(Ce0.919Nd0.081)O3, (Ba0.974Gd0.026)(Ce0.872Gd0.128)O2.875, and Ba(Ce0.85Yb0.15)O2.925. As a consequence of the greater ability of larger cations to exist on the Ba site, the H2O adsorption and proton conductivities of large-cation doped barium cerates are lower than those of small-cation doped analogs.

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Peng, Xiang, Huan Liu, Kevin Siggers, and Zheng Liu. "Pipeline corrosion defect parameterisation with magnetic flux leakage inspection: a contextual representation approach." Insight - Non-Destructive Testing and Condition Monitoring 63, no. 2 (February 1, 2021): 95–101. http://dx.doi.org/10.1784/insi.2021.63.2.95.

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Corrosion is one of the significant reasons for oil and gas pipeline failures. In pipeline integrity management programmes, the magnetic flux leakage (MFL) technique is widely used to detect and quantify corrosion defects. The inspection results of MFL list the profiles of individual corrosion defects; however, the structural safety of a pipeline not only depends on the size of individual corrosion defects but also the pattern of closely spaced defects. To achieve a contextual defect representation, the concept of parameterisation, which considers the adjacent defects as additional information of the central defect, is proposed in this study. The process through which to realise this contextual representation is described in this paper. Three parameterisation models are proposed and a two-dimensional Gaussian function is employed to model the interaction strength between adjacent defects. The experimental results demonstrate that the shape context (SC) model associated with the interaction strength function (ISF) shares the highest similarity with human inspectors in comparison with the other two models. Thus, the proposed parameterisation approach can be used to retrieve similar corrosion defects and analyse defect population distribution along a pipeline.

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Dinache, George, Marinel Drignei, Stergios Ganatsios, Eric Jovenet, Radu Costea, Florin Savulescu, and Stelian Lupascu. "Theoretical Aspects, Modern Treatment Options and Practical Case Presentations in Hip and Knee Tumoral and Revision Bone Defect Reconstruction Surgery." Revista de Chimie 69, no. 12 (January 15, 2019): 3664–68. http://dx.doi.org/10.37358/rc.18.12.6815.

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Bone defects are a challenge to any and in fact every orthopedic surgeon, be they as a consequence of trauma, peri-implant bone loss as is the case in revision surgery or, more often than not, in tumors of the bone. These defects are in most cases difficult to reconstruct, but even more so in the case when they are located around the major joints of the lower limb, i.e. the hip and the knee. We focus in this article on acetabular bone defects as well as on defects around the knee (distal femur and proximal tibia). We present implant possibilities and modern means of reconstructing the bone defect using augments. We also present three representative cases from our Clinic, to further exemplify the discussed concepts. We present our opinions on reconstructing bone defects after tumor and revision surgery in the hip and knee and we draw conclusions.

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