Semi-automatic registration of 3D orthodontics models from photographs

Science.gov (United States)

Destrez, Raphaël.; Treuillet, Sylvie; Lucas, Yves; Albouy-Kissi, Benjamin

2013-03-01

In orthodontics, a common practice used to diagnose and plan the treatment is the dental cast. After digitization by a CT-scan or a laser scanner, the obtained 3D surface models can feed orthodontics numerical tools for computer-aided diagnosis and treatment planning. One of the pre-processing critical steps is the 3D registration of dental arches to obtain the occlusion of these numerical models. For this task, we propose a vision based method to automatically compute the registration based on photos of patient mouth. From a set of matched singular points between two photos and the dental 3D models, the rigid transformation to apply to the mandible to be in contact with the maxillary may be computed by minimizing the reprojection errors. During a precedent study, we established the feasibility of this visual registration approach with a manual selection of singular points. This paper addresses the issue of automatic point detection. Based on a priori knowledge, histogram thresholding and edge detection are used to extract specific points in 2D images. Concurrently, curvatures information detects 3D corresponding points. To improve the quality of the final registration, we also introduce a combined optimization of the projection matrix with the 2D/3D point positions. These new developments are evaluated on real data by considering the reprojection errors and the deviation angles after registration in respect to the manual reference occlusion realized by a specialist.

Automatic detection of artifacts in converted S3D video

Science.gov (United States)

Bokov, Alexander; Vatolin, Dmitriy; Zachesov, Anton; Belous, Alexander; Erofeev, Mikhail

2014-03-01

In this paper we present algorithms for automatically detecting issues specific to converted S3D content. When a depth-image-based rendering approach produces a stereoscopic image, the quality of the result depends on both the depth maps and the warping algorithms. The most common problem with converted S3D video is edge-sharpness mismatch. This artifact may appear owing to depth-map blurriness at semitransparent edges: after warping, the object boundary becomes sharper in one view and blurrier in the other, yielding binocular rivalry. To detect this problem we estimate the disparity map, extract boundaries with noticeable differences, and analyze edge-sharpness correspondence between views. We pay additional attention to cases involving a complex background and large occlusions. Another problem is detection of scenes that lack depth volume: we present algorithms for detecting at scenes and scenes with at foreground objects. To identify these problems we analyze the features of the RGB image as well as uniform areas in the depth map. Testing of our algorithms involved examining 10 Blu-ray 3D releases with converted S3D content, including Clash of the Titans, The Avengers, and The Chronicles of Narnia: The Voyage of the Dawn Treader. The algorithms we present enable improved automatic quality assessment during the production stage.

Nature of impurities in fertilizers containing EDDHMA/Fe(3+), EDDHSA/Fe(3+), and EDDCHA/Fe(3+) chelates.

Science.gov (United States)

Alvarez-Fernández, Ana; Cremonini, Mauro A; Sierra, Miguel A; Placucci, Giuseppe; Lucena, Juan J

2002-01-16

Iron chelates derived from ethylenediaminedi(o-hydroxyphenylacetic) acid (EDDHA), ethylenediaminedi(o-hydroxy-p-methylphenylacetic) acid (EDDHMA), ethylenediaminedi(2-hydroxy-5-sulfophenylacetic) acid (EDDHSA), and ethylenediaminedi(5-carboxy-2-hydroxyphenylacetic) acid (EDDCHA) are remarkably efficient in correcting iron chlorosis in plants growing in alkaline soils. This work reports the determination of impurities in commercial samples of fertilizers containing EDDHMA/Fe(3+), EDDHSA/Fe(3+), and EDDCHA/Fe(3+). The active components (EDDHMA/Fe(3+), EDDHSA/Fe(3+), and EDDCHA/Fe(3+)) were separated easily from other compounds present in the fertilizers by HPLC. Comparison of the retention times and the UV-visible spectra of the peaks obtained from commercial EDDHSA/Fe(3+) and EDDCHA/Fe(3+) samples with those of standard solutions showed that unreacted starting materials (p-hydroxybenzenesulfonic acid and p-hydroxybenzoic acid, respectively) were always present in the commercial products. 1D and 2D NMR experiments showed that commercial fertilizers based on EDDHMA/Fe(3+) contained impurities having structures tentatively assigned to iron chelates of two isomers of EDDHMA. These findings suggest that current production processes of iron chelates used in agriculture need to be improved.

Electronic structures and magnetic properties of 3d and 4d transition-metal impurities in ferromagnetic Fe

CERN Document Server

Park, J H; Min, B I; Cho, H S

2000-01-01

Employing the self-consistent local approach, the tight-binding linear-muffin-tin orbital recursion method, we have investigated the electronic structures and the magnetic properties of 3d and 4d transition-metal (TM) impurities in ferromagnetic bcc Fe. In both 3d and 4d TM impurities, virtual bound states appear and are characterized by a high density of states in the energy spectrum. The characters of the states are studied by calculating the bond order between interaction orbitals. For early TM impurities, the states at the impurity sites have more antibonding characters, while the states at neighboring Fe sites have more bonding characters. For late TM impurities, the situation is reversed. late TM impurities of both the 3d and the 4d TM series have the same magnetic ordering as the host Fe atoms whereas early TM impurities have magnetic moments antiparallel to that of the host. As for the Mn impurity, an inward relaxation of neighboring Fe atoms stabilizes the antiferromagnetic ordering with respect to t...

AUTOMATIC TEXTURE RECONSTRUCTION OF 3D CITY MODEL FROM OBLIQUE IMAGES

Directory of Open Access Journals (Sweden)

J. Kang

2016-06-01

Full Text Available In recent years, the photorealistic 3D city models are increasingly important in various geospatial applications related to virtual city tourism, 3D GIS, urban planning, real-estate management. Besides the acquisition of high-precision 3D geometric data, texture reconstruction is also a crucial step for generating high-quality and visually realistic 3D models. However, most of the texture reconstruction approaches are probably leading to texture fragmentation and memory inefficiency. In this paper, we introduce an automatic framework of texture reconstruction to generate textures from oblique images for photorealistic visualization. Our approach include three major steps as follows: mesh parameterization, texture atlas generation and texture blending. Firstly, mesh parameterization procedure referring to mesh segmentation and mesh unfolding is performed to reduce geometric distortion in the process of mapping 2D texture to 3D model. Secondly, in the texture atlas generation step, the texture of each segmented region in texture domain is reconstructed from all visible images with exterior orientation and interior orientation parameters. Thirdly, to avoid color discontinuities at boundaries between texture regions, the final texture map is generated by blending texture maps from several corresponding images. We evaluated our texture reconstruction framework on a dataset of a city. The resulting mesh model can get textured by created texture without resampling. Experiment results show that our method can effectively mitigate the occurrence of texture fragmentation. It is demonstrated that the proposed framework is effective and useful for automatic texture reconstruction of 3D city model.

Automatic system for 3D reconstruction of the chick eye based on digital photographs.

Science.gov (United States)

Wong, Alexander; Genest, Reno; Chandrashekar, Naveen; Choh, Vivian; Irving, Elizabeth L

2012-01-01

The geometry of anatomical specimens is very complex and accurate 3D reconstruction is important for morphological studies, finite element analysis (FEA) and rapid prototyping. Although magnetic resonance imaging, computed tomography and laser scanners can be used for reconstructing biological structures, the cost of the equipment is fairly high and specialised technicians are required to operate the equipment, making such approaches limiting in terms of accessibility. In this paper, a novel automatic system for 3D surface reconstruction of the chick eye from digital photographs of a serially sectioned specimen is presented as a potential cost-effective and practical alternative. The system is designed to allow for automatic detection of the external surface of the chick eye. Automatic alignment of the photographs is performed using a combination of coloured markers and an algorithm based on complex phase order likelihood that is robust to noise and illumination variations. Automatic segmentation of the external boundaries of the eye from the aligned photographs is performed using a novel level-set segmentation approach based on a complex phase order energy functional. The extracted boundaries are sampled to construct a 3D point cloud, and a combination of Delaunay triangulation and subdivision surfaces is employed to construct the final triangular mesh. Experimental results using digital photographs of the chick eye show that the proposed system is capable of producing accurate 3D reconstructions of the external surface of the eye. The 3D model geometry is similar to a real chick eye and could be used for morphological studies and FEA.

α-Fe2O3 lithium battery anodes by nanocasting strategy from ordered 2D and 3D templates

International Nuclear Information System (INIS)

Di Lupo, F.; Gerbaldi, C.; Casino, S.; Francia, C.; Meligrana, G.; Tuel, A.; Penazzi, N.

2014-01-01

Highlights: • Nanosized α-Fe 2 O 3 lithium battery conversion anodes with tunable morphology. • Nanocasting technique using MCM-41 and MCM-48 silica moulds is adopted. • Textural/morphological characteristics define the electrochemical behaviour. • α-Fe 2 O 3 replica of MCM-41 exhibits stable capacity (∼300 mA h g −1 ) after 100 cycles. • α-Fe 2 O 3 replica of MCM-41 shows promising prospects as high-capacity Li-ion battery anode. - Abstract: Nanocasting strategy is here proposed as effective approach to tune structure and size of α-Fe 2 O 3 active nanoparticles as a promising anode material for Li-ion cells. MCM-41 and MCM-48 silicas, presenting hexagonal 2D and cubic 3D symmetry, respectively, and regular pore diameter of about 4 nm are selected as moulds. The structural–morphological and electrochemical characteristics are assessed by X-ray diffraction, transmission electron microscopy, N 2 physisorption at 77 K, cyclic voltammetry and galvanostatic discharge/charge cycling. It is here demonstrated that structural–morphological features change accordingly to the template used and careful control of the texture/particle characteristics is likely a fundamental variable noticeably affecting the cycling behaviour

Automatic respiration tracking for radiotherapy using optical 3D camera

Science.gov (United States)

Li, Tuotuo; Geng, Jason; Li, Shidong

2013-03-01

Rapid optical three-dimensional (O3D) imaging systems provide accurate digitized 3D surface data in real-time, with no patient contact nor radiation. The accurate 3D surface images offer crucial information in image-guided radiation therapy (IGRT) treatments for accurate patient repositioning and respiration management. However, applications of O3D imaging techniques to image-guided radiotherapy have been clinically challenged by body deformation, pathological and anatomical variations among individual patients, extremely high dimensionality of the 3D surface data, and irregular respiration motion. In existing clinical radiation therapy (RT) procedures target displacements are caused by (1) inter-fractional anatomy changes due to weight, swell, food/water intake; (2) intra-fractional variations from anatomy changes within any treatment session due to voluntary/involuntary physiologic processes (e.g. respiration, muscle relaxation); (3) patient setup misalignment in daily reposition due to user errors; and (4) changes of marker or positioning device, etc. Presently, viable solution is lacking for in-vivo tracking of target motion and anatomy changes during the beam-on time without exposing patient with additional ionized radiation or high magnet field. Current O3D-guided radiotherapy systems relay on selected points or areas in the 3D surface to track surface motion. The configuration of the marks or areas may change with time that makes it inconsistent in quantifying and interpreting the respiration patterns. To meet the challenge of performing real-time respiration tracking using O3D imaging technology in IGRT, we propose a new approach to automatic respiration motion analysis based on linear dimensionality reduction technique based on PCA (principle component analysis). Optical 3D image sequence is decomposed with principle component analysis into a limited number of independent (orthogonal) motion patterns (a low dimension eigen-space span by eigen-vectors). New

Three-dimensional (3D α-Fe2O3/polypyrrole (PPy nanocomposite for effective electromagnetic absorption

Directory of Open Access Journals (Sweden)

Wanchun Jiang

2016-06-01

Full Text Available The lightweight and 3-dimensional reticulated α-Fe2O3/PPy hybrids were successfully fabricated via a facile one-pot polyreaction. The measured complex permittivity and microwave attenuation performance suggest that the dielectric properties of PPy can be regulated by the mass ratio of added α-Fe2O3. The two dielectric resonance peaks of complex permittivity can be ascribed to the interface capacitor-like structure. An equivalent circuit model was established to explain the nonlinear resonance behavior of the α-Fe2O3/PPy wax composites. The addition of α-Fe2O3 properly tuned the dielectric constant to endow the composites with highly efficient microwave absorption. The minimum reflection loss of α-Fe2O3/PPy wax composites were enhanced to nearly −29dB with an effective bandwidth (RL≤ − 10dB up to 5.0GHz. The numerical method was proposed to calculate the optimum thickness for minimum RL at expected frequency by detailed investigation on the transmission formula. Moreover, the required thickness for optimum absorption efficiency at expected frequency can be obtained directly.

Automatic co-registration of 3D multi-sensor point clouds

Science.gov (United States)

Persad, Ravi Ancil; Armenakis, Costas

2017-08-01

We propose an approach for the automatic coarse alignment of 3D point clouds which have been acquired from various platforms. The method is based on 2D keypoint matching performed on height map images of the point clouds. Initially, a multi-scale wavelet keypoint detector is applied, followed by adaptive non-maxima suppression. A scale, rotation and translation-invariant descriptor is then computed for all keypoints. The descriptor is built using the log-polar mapping of Gabor filter derivatives in combination with the so-called Rapid Transform. In the final step, source and target height map keypoint correspondences are determined using a bi-directional nearest neighbour similarity check, together with a threshold-free modified-RANSAC. Experiments with urban and non-urban scenes are presented and results show scale errors ranging from 0.01 to 0.03, 3D rotation errors in the order of 0.2° to 0.3° and 3D translation errors from 0.09 m to 1.1 m.

Facilitating coronary artery evaluation in MDCT using a 3D automatic vessel segmentation tool

International Nuclear Information System (INIS)

Fawad Khan, M.; Gurung, Jessen; Maataoui, Adel; Brehmer, Boris; Herzog, Christopher; Vogl, Thomas J.; Wesarg, Stefan; Dogan, Selami; Ackermann, Hanns; Assmus, Birgit

2006-01-01

The purpose of this study was to investigate a 3D coronary artery segmentation algorithm using 16-row MDCT data sets. Fifty patients underwent cardiac CT (Sensation 16, Siemens) and coronary angiography. Automatic and manual detection of coronary artery stenosis was performed. A 3D coronary artery segmentation algorithm (Fraunhofer Institute for Computer Graphics, Darmstadt) was used for automatic evaluation. All significant stenoses (>50%) in vessels >1.5 mm in diameter were protocoled. Each detection tool was used by one reader who was blinded to the results of the other detection method and the results of coronary angiography. Sensitivity and specificity were determined for automatic and manual detection as well as was the time for both CT-based evaluation methods. The overall sensitivity and specificity of the automatic and manual approach were 93.1 vs. 95.83% and 86.1 vs. 81.9%. The time required for automatic evaluation was significantly shorter than with the manual approach, i.e., 246.04±43.17 s for the automatic approach and 526.88±45.71 s for the manual approach (P<0.0001). In 94% of the coronary artery branches, automatic detection required less time than the manual approach. Automatic coronary vessel evaluation is feasible. It reduces the time required for cardiac CT evaluation with similar sensitivity and specificity as well as facilitates the evaluation of MDCT coronary angiography in a standardized fashion. (orig.)

Automatic Generation of 3D Building Models with Multiple Roofs

Institute of Scientific and Technical Information of China (English)

Kenichi Sugihara; Yoshitugu Hayashi

2008-01-01

Based on building footprints (building polygons) on digital maps, we are proposing the GIS and CG integrated system that automatically generates 3D building models with multiple roofs. Most building polygons' edges meet at right angles (orthogonal polygon). The integrated system partitions orthogonal building polygons into a set of rectangles and places rectangular roofs and box-shaped building bodies on these rectangles. In order to partition an orthogonal polygon, we proposed a useful polygon expression in deciding from which vertex a dividing line is drawn. In this paper, we propose a new scheme for partitioning building polygons and show the process of creating 3D roof models.

Approach of automatic 3D geological mapping: the case of the Kovdor phoscorite-carbonatite complex, NW Russia.

Science.gov (United States)

Kalashnikov, A O; Ivanyuk, G Yu; Mikhailova, J A; Sokharev, V A

2017-07-31

We have developed an approach for automatic 3D geological mapping based on conversion of chemical composition of rocks to mineral composition by logical computation. It allows to calculate mineral composition based on bulk rock chemistry, interpolate the mineral composition in the same way as chemical composition, and, finally, build a 3D geological model. The approach was developed for the Kovdor phoscorite-carbonatite complex containing the Kovdor baddeleyite-apatite-magnetite deposit. We used 4 bulk rock chemistry analyses - Fe magn , P 2 O 5 , CO 2 and SiO 2 . We used four techniques for prediction of rock types - calculation of normative mineral compositions (norms), multiple regression, artificial neural network and developed by logical evaluation. The two latter became the best. As a result, we distinguished 14 types of phoscorites (forsterite-apatite-magnetite-carbonate rock), carbonatite and host rocks. The results show good convergence with our petrographical studies of the deposit, and recent manually built maps. The proposed approach can be used as a tool of a deposit genesis reconstruction and preliminary geometallurgical modelling.

Automatic orientation and 3D modelling from markerless rock art imagery

Science.gov (United States)

Lerma, J. L.; Navarro, S.; Cabrelles, M.; Seguí, A. E.; Hernández, D.

2013-02-01

This paper investigates the use of two detectors and descriptors on image pyramids for automatic image orientation and generation of 3D models. The detectors and descriptors replace manual measurements and are used to detect, extract and match features across multiple imagery. The Scale-Invariant Feature Transform (SIFT) and the Speeded Up Robust Features (SURF) will be assessed based on speed, number of features, matched features, and precision in image and object space depending on the adopted hierarchical matching scheme. The influence of applying in addition Area Based Matching (ABM) with normalised cross-correlation (NCC) and least squares matching (LSM) is also investigated. The pipeline makes use of photogrammetric and computer vision algorithms aiming minimum interaction and maximum accuracy from a calibrated camera. Both the exterior orientation parameters and the 3D coordinates in object space are sequentially estimated combining relative orientation, single space resection and bundle adjustment. The fully automatic image-based pipeline presented herein to automate the image orientation step of a sequence of terrestrial markerless imagery is compared with manual bundle block adjustment and terrestrial laser scanning (TLS) which serves as ground truth. The benefits of applying ABM after FBM will be assessed both in image and object space for the 3D modelling of a complex rock art shelter.

Net Shape 3D Printed NdFeB Permanent Magnet

OpenAIRE

Jacimovic, J.; Binda, F.; Herrmann, L. G.; Greuter, F.; Genta, J.; Calvo, M.; Tomse, T.; Simon, R. A.

2016-01-01

For two decades, NdFeB based magnets have been a critical component in a range of electrical devices engaged in energy production and conversion. The magnet shape and the internal microstructure of the selected NdFeB grade govern their efficiency and size. However, stricter requirements on device efficiency call for better performing magnets preferably with novel functionality not achievable today. Here we use 3D metal printing by Selective Laser Melting to fabricate dense net shape permanent...

A new methodology for automatic detection of reference points in 3D cephalometry: A pilot study.

Science.gov (United States)

Ed-Dhahraouy, Mohammed; Riri, Hicham; Ezzahmouly, Manal; Bourzgui, Farid; El Moutaoukkil, Abdelmajid

2018-04-05

The aim of this study was to develop a new method for an automatic detection of reference points in 3D cephalometry to overcome the limits of 2D cephalometric analyses. A specific application was designed using the C++ language for automatic and manual identification of 21 (reference) points on the craniofacial structures. Our algorithm is based on the implementation of an anatomical and geometrical network adapted to the craniofacial structure. This network was constructed based on the anatomical knowledge of the 3D cephalometric (reference) points. The proposed algorithm was tested on five CBCT images. The proposed approach for the automatic 3D cephalometric identification was able to detect 21 points with a mean error of 2.32mm. In this pilot study, we propose an automated methodology for the identification of the 3D cephalometric (reference) points. A larger sample will be implemented in the future to assess the method validity and reliability. Copyright © 2018 CEO. Published by Elsevier Masson SAS. All rights reserved.

Self-assembled 3D flower-like Ni2+-Fe3+ layered double hydroxides and their calcined products

International Nuclear Information System (INIS)

Xiao Ting; Tang Yiwen; Jia Zhiyong; Li Dawei; Hu Xiaoyan; Li Bihui; Luo Lijuan

2009-01-01

This paper describes a facile solvothermal method to synthesize self-assembled three-dimensional (3D) Ni 2+ -Fe 3+ layered double hydroxides (LDHs). Flower-like Ni 2+ -Fe 3+ LDHs constructed of thin nanopetals were obtained using ethylene glycol (EG) as a chelating reagent and urea as a hydrolysis agent. The reaction mechanism and self-assembly process are discussed. After calcinating the as-prepared LDHs at 450 0 C in nitrogen gas, porous NiO/NiFe 2 O 4 nanosheets were obtained. This work resulted in the development of a simple, cheap, and effective route for the fabrication of large area Ni 2+ -Fe 3+ LDHs as well as porous NiO/NiFe 2 O 4 nanosheets.

A framework for automatic creation of gold-standard rigid 3D-2D registration datasets.

Science.gov (United States)

Madan, Hennadii; Pernuš, Franjo; Likar, Boštjan; Špiclin, Žiga

2017-02-01

Advanced image-guided medical procedures incorporate 2D intra-interventional information into pre-interventional 3D image and plan of the procedure through 3D/2D image registration (32R). To enter clinical use, and even for publication purposes, novel and existing 32R methods have to be rigorously validated. The performance of a 32R method can be estimated by comparing it to an accurate reference or gold standard method (usually based on fiducial markers) on the same set of images (gold standard dataset). Objective validation and comparison of methods are possible only if evaluation methodology is standardized, and the gold standard  dataset is made publicly available. Currently, very few such datasets exist and only one contains images of multiple patients acquired during a procedure. To encourage the creation of gold standard 32R datasets, we propose an automatic framework. The framework is based on rigid registration of fiducial markers. The main novelty is spatial grouping of fiducial markers on the carrier device, which enables automatic marker localization and identification across the 3D and 2D images. The proposed framework was demonstrated on clinical angiograms of 20 patients. Rigid 32R computed by the framework was more accurate than that obtained manually, with the respective target registration error below 0.027 mm compared to 0.040 mm. The framework is applicable for gold standard setup on any rigid anatomy, provided that the acquired images contain spatially grouped fiducial markers. The gold standard datasets and software will be made publicly available.

Efficient Semi-Automatic 3D Segmentation for Neuron Tracing in Electron Microscopy Images

Science.gov (United States)

Jones, Cory; Liu, Ting; Cohan, Nathaniel Wood; Ellisman, Mark; Tasdizen, Tolga

2015-01-01

0.1. Background In the area of connectomics, there is a significant gap between the time required for data acquisition and dense reconstruction of the neural processes contained in the same dataset. Automatic methods are able to eliminate this timing gap, but the state-of-the-art accuracy so far is insufficient for use without user corrections. If completed naively, this process of correction can be tedious and time consuming. 0.2. New Method We present a new semi-automatic method that can be used to perform 3D segmentation of neurites in EM image stacks. It utilizes an automatic method that creates a hierarchical structure for recommended merges of superpixels. The user is then guided through each predicted region to quickly identify errors and establish correct links. 0.3. Results We tested our method on three datasets with both novice and expert users. Accuracy and timing were compared with published automatic, semi-automatic, and manual results. 0.4. Comparison with Existing Methods Post-automatic correction methods have also been used in [1] and [2]. These methods do not provide navigation or suggestions in the manner we present. Other semi-automatic methods require user input prior to the automatic segmentation such as [3] and [4] and are inherently different than our method. 0.5. Conclusion Using this method on the three datasets, novice users achieved accuracy exceeding state-of-the-art automatic results, and expert users achieved accuracy on par with full manual labeling but with a 70% time improvement when compared with other examples in publication. PMID:25769273

Automatic paper sliceform design from 3D solid models.

Science.gov (United States)

Le-Nguyen, Tuong-Vu; Low, Kok-Lim; Ruiz, Conrado; Le, Sang N

2013-11-01

A paper sliceform or lattice-style pop-up is a form of papercraft that uses two sets of parallel paper patches slotted together to make a foldable structure. The structure can be folded flat, as well as fully opened (popped-up) to make the two sets of patches orthogonal to each other. Automatic design of paper sliceforms is still not supported by existing computational models and remains a challenge. We propose novel geometric formulations of valid paper sliceform designs that consider the stability, flat-foldability and physical realizability of the designs. Based on a set of sufficient construction conditions, we also present an automatic algorithm for generating valid sliceform designs that closely depict the given 3D solid models. By approximating the input models using a set of generalized cylinders, our method significantly reduces the search space for stable and flat-foldable sliceforms. To ensure the physical realizability of the designs, the algorithm automatically generates slots or slits on the patches such that no two cycles embedded in two different patches are interlocking each other. This guarantees local pairwise assembility between patches, which is empirically shown to lead to global assembility. Our method has been demonstrated on a number of example models, and the output designs have been successfully made into real paper sliceforms.

α-Fe{sub 2}O{sub 3} lithium battery anodes by nanocasting strategy from ordered 2D and 3D templates

Energy Technology Data Exchange (ETDEWEB)

Di Lupo, F. [GAME Lab, Department of Applied Science and Technology – DISAT, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Turin (Italy); Gerbaldi, C., E-mail: claudio.gerbaldi@polito.it [GAME Lab, Department of Applied Science and Technology – DISAT, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Turin (Italy); Casino, S.; Francia, C.; Meligrana, G. [GAME Lab, Department of Applied Science and Technology – DISAT, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Turin (Italy); Tuel, A. [Institut de Recherches sur la Catalyse, IRC-CNRS (UPR 5401), 2 Avenue Albert Einstein, 69626 Villeurbanne Cedex (France); Penazzi, N. [GAME Lab, Department of Applied Science and Technology – DISAT, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Turin (Italy)

2014-12-05

Highlights: • Nanosized α-Fe{sub 2}O{sub 3} lithium battery conversion anodes with tunable morphology. • Nanocasting technique using MCM-41 and MCM-48 silica moulds is adopted. • Textural/morphological characteristics define the electrochemical behaviour. • α-Fe{sub 2}O{sub 3} replica of MCM-41 exhibits stable capacity (∼300 mA h g{sup −1}) after 100 cycles. • α-Fe{sub 2}O{sub 3} replica of MCM-41 shows promising prospects as high-capacity Li-ion battery anode. - Abstract: Nanocasting strategy is here proposed as effective approach to tune structure and size of α-Fe{sub 2}O{sub 3} active nanoparticles as a promising anode material for Li-ion cells. MCM-41 and MCM-48 silicas, presenting hexagonal 2D and cubic 3D symmetry, respectively, and regular pore diameter of about 4 nm are selected as moulds. The structural–morphological and electrochemical characteristics are assessed by X-ray diffraction, transmission electron microscopy, N{sub 2} physisorption at 77 K, cyclic voltammetry and galvanostatic discharge/charge cycling. It is here demonstrated that structural–morphological features change accordingly to the template used and careful control of the texture/particle characteristics is likely a fundamental variable noticeably affecting the cycling behaviour.

Comparing a novel automatic 3D method for LGE-CMR quantification of scar size with established methods.

Science.gov (United States)

Woie, Leik; Måløy, Frode; Eftestøl, Trygve; Engan, Kjersti; Edvardsen, Thor; Kvaløy, Jan Terje; Ørn, Stein

2014-02-01

Current methods for the estimation of infarct size by late-enhanced cardiac magnetic imaging are based upon 2D analysis that first determines the size of the infarction in each slice, and thereafter adds the infarct sizes from each slice to generate a volume. We present a novel, automatic 3D method that estimates infarct size by a simultaneous analysis of all pixels from all slices. In a population of 54 patients with ischemic scars, the infarct size estimated by the automatic 3D method was compared with four established 2D methods. The new 3D method defined scar as the sum of all pixels with signal intensity (SI) ≥35 % of max SI from the complete myocardium, border zone: SI 35-50 % of max SI and core as SI ≥50 % of max SI. The 3D method yielded smaller infarct size (-2.8 ± 2.3 %) and core size (-3.0 ± 1.7 %) than the 2D method most similar to ours. There was no difference in the size of the border zone (0.2 ± 1.4 %). The 3D method demonstrated stronger correlations between scar size and left ventricular (LV) remodelling parameters (LV ejection fraction: r = -0.71, p 3D automatic method is without the need for manual demarcation of the scar; it is less time-consuming and has a stronger correlation with remodelling parameters compared with existing methods.

Automatic Generation of Structural Building Descriptions from 3D Point Cloud Scans

DEFF Research Database (Denmark)

Ochmann, Sebastian; Vock, Richard; Wessel, Raoul

2013-01-01

We present a new method for automatic semantic structuring of 3D point clouds representing buildings. In contrast to existing approaches which either target the outside appearance like the facade structure or rather low-level geometric structures, we focus on the building’s interior using indoor...... scans to derive high-level architectural entities like rooms and doors. Starting with a registered 3D point cloud, we probabilistically model the affiliation of each measured point to a certain room in the building. We solve the resulting clustering problem using an iterative algorithm that relies...

1D Magnetic Materials of Fe3O4 and Fe with High Performance of Microwave Absorption Fabricated by Electrospinning Method

Science.gov (United States)

Han, Rui; Li, Wei; Pan, Weiwei; Zhu, Minggang; Zhou, Dong; Li, Fa-shen

2014-01-01

Fe3O4 and Fe nanowires are successfully fabricated by electrospinning method and reduction process. Wiry microstructures were achieved with the phase transformation from α-Fe2O3 to Fe3O4 and Fe by partial and full reduction, while still preserving the wire morphology. The diameters of the Fe3O4 and Fe nanowires are approximately 50–60 nm and 30–40 nm, respectively. The investigation of microwave absorption reveals that the Fe3O4 nanowires exhibit excellent microwave absorbing properties. For paraffin-based composite containing 50% weight concentration of Fe3O4 nanowires, the minimum reflection loss reaches −17.2 dB at 6.2 GHz with the matching thickness of 5.5 mm. Furthermore, the calculation shows that the modulus of the ratio between the complex permittivity and permeability |ε/μ| is far away from unity at the minimum reflection loss point, which is quite different from the traditional opinions. PMID:25510415

Automatic contact algorithm in ppercase[dyna3d] for crashworthiness and impact problems

International Nuclear Information System (INIS)

Whirley, Robert G.; Engelmann, Bruce E.

1994-01-01

This paper presents a new approach for the automatic definition and treatment of mechanical contact in explicit non-linear finite element analysis. Automatic contact offers the benefits of significantly reduced model construction time and fewer opportunities for user error, but faces significant challenges in reliability and computational costs. Key aspects of the proposed new method include automatic identification of adjacent and opposite surfaces in the global search phase, and the use of a well-defined surface normal which allows a consistent treatment of shell intersection and corner contact conditions without adhoc rules. The paper concludes with three examples which illustrate the performance of the newly proposed algorithm in the public ppercase[dyna3d] code. ((orig.))

The 54Fe(d,t)53Fe reaction and the neutron configuration in 54Fe

International Nuclear Information System (INIS)

England, J.B.A.; Ophel, T.R.; Johnston, A.; Zeller, A.F.

1980-07-01

The 54 Fe(d,t) 53 Fe reaction has been used to study the levels populated in 54 Fe in an attempt to establish the neutron configuration in 54 Fe. The states observed show clear evidence for a 2p-4h admixture in 54 Fe. In particular, the strength of the first 3/2 - level relative to the 7/2 - ground state transition is 3-4 times that in neighbouring N = 28 nuclei

Non-rigid registration of 3D ultrasound for neurosurgery using automatic feature detection and matching.

Science.gov (United States)

Machado, Inês; Toews, Matthew; Luo, Jie; Unadkat, Prashin; Essayed, Walid; George, Elizabeth; Teodoro, Pedro; Carvalho, Herculano; Martins, Jorge; Golland, Polina; Pieper, Steve; Frisken, Sarah; Golby, Alexandra; Wells, William

2018-06-04

The brain undergoes significant structural change over the course of neurosurgery, including highly nonlinear deformation and resection. It can be informative to recover the spatial mapping between structures identified in preoperative surgical planning and the intraoperative state of the brain. We present a novel feature-based method for achieving robust, fully automatic deformable registration of intraoperative neurosurgical ultrasound images. A sparse set of local image feature correspondences is first estimated between ultrasound image pairs, after which rigid, affine and thin-plate spline models are used to estimate dense mappings throughout the image. Correspondences are derived from 3D features, distinctive generic image patterns that are automatically extracted from 3D ultrasound images and characterized in terms of their geometry (i.e., location, scale, and orientation) and a descriptor of local image appearance. Feature correspondences between ultrasound images are achieved based on a nearest-neighbor descriptor matching and probabilistic voting model similar to the Hough transform. Experiments demonstrate our method on intraoperative ultrasound images acquired before and after opening of the dura mater, during resection and after resection in nine clinical cases. A total of 1620 automatically extracted 3D feature correspondences were manually validated by eleven experts and used to guide the registration. Then, using manually labeled corresponding landmarks in the pre- and post-resection ultrasound images, we show that our feature-based registration reduces the mean target registration error from an initial value of 3.3 to 1.5 mm. This result demonstrates that the 3D features promise to offer a robust and accurate solution for 3D ultrasound registration and to correct for brain shift in image-guided neurosurgery.

AUTOMATIC 3D MAPPING USING MULTIPLE UNCALIBRATED CLOSE RANGE IMAGES

Directory of Open Access Journals (Sweden)

M. Rafiei

2013-09-01

Full Text Available Automatic three-dimensions modeling of the real world is an important research topic in the geomatics and computer vision fields for many years. By development of commercial digital cameras and modern image processing techniques, close range photogrammetry is vastly utilized in many fields such as structure measurements, topographic surveying, architectural and archeological surveying, etc. A non-contact photogrammetry provides methods to determine 3D locations of objects from two-dimensional (2D images. Problem of estimating the locations of 3D points from multiple images, often involves simultaneously estimating both 3D geometry (structure and camera pose (motion, it is commonly known as structure from motion (SfM. In this research a step by step approach to generate the 3D point cloud of a scene is considered. After taking images with a camera, we should detect corresponding points in each two views. Here an efficient SIFT method is used for image matching for large baselines. After that, we must retrieve the camera motion and 3D position of the matched feature points up to a projective transformation (projective reconstruction. Lacking additional information on the camera or the scene makes the parallel lines to be unparalleled. The results of SfM computation are much more useful if a metric reconstruction is obtained. Therefor multiple views Euclidean reconstruction applied and discussed. To refine and achieve the precise 3D points we use more general and useful approach, namely bundle adjustment. At the end two real cases have been considered to reconstruct (an excavation and a tower.

Fabrication of highly oriented D0{sub 3}-Fe{sub 3}Si nanocrystals by solid-state dewetting of Si ultrathin layer

Energy Technology Data Exchange (ETDEWEB)

Naito, Muneyuki, E-mail: naito22@center.konan-u.ac.jp [Department of Chemistry, Konan University, Okamoto, Higashinada, Kobe, Hyogo 658-8501 (Japan); Nakagawa, Tatsuhiko; Machida, Nobuya; Shigematsu, Toshihiko [Department of Chemistry, Konan University, Okamoto, Higashinada, Kobe, Hyogo 658-8501 (Japan); Nakao, Motoi [Graduate School of Engineering, Kyushu Institute of Technology, Sensui, Tobata, Kitakyushu, Fukuoka 804-8550 (Japan); Sudoh, Koichi [The Institute of Scientific and Industrial Research, Osaka University, Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)

2013-07-31

In this paper, highly oriented nanocrystals of Fe{sub 3}Si with a D0{sub 3} structure are fabricated on SiO{sub 2} using ultrathin Si on insulator substrate. First, (001) oriented Si nanocrystals are formed on the SiO{sub 2} layer by solid state dewetting of the top Si layer. Then, Fe addition to the Si nanocrystals is performed by reactive deposition epitaxy and post-deposition annealing at 500 °C. The structures of the Fe–Si nanocrystals are analyzed by cross-sectional transmission electron microscopy and nanobeam electron diffraction. We observe that Fe{sub 3}Si nanocrystals with D0{sub 3}, B2, and A2 structures coexist on the 1-h post-annealed samples. Prolonged annealing at 500 °C is effective in obtaining Fe{sub 3}Si nanocrystals with a D0{sub 3} single phase, thereby promoting structural ordering in the nanocrystals. We discuss the formation process of the highly oriented D0{sub 3}-Fe{sub 3}Si nanocrystals on the basis of the atomistic structural information. - Highlights: • Highly oriented Fe–Si nanocrystals (NCs) are fabricated by reactive deposition. • Si NCs formed by solid state dewetting of Si thin layers are used as seed crystals. • The structures of Fe–Si NCs are analyzed by nanobeam electron diffraction. • Most of Fe–Si NCs possess the D0{sub 3} structure after post-deposition annealing.

tavg3_3d_chm_Fe: MERRA Chem 3D IAU, Precip Mass Flux, Time average 3-hourly 1.25 x 1 degree V5.2.0 (MAT3FECHM) at GES DISC

Data.gov (United States)

National Aeronautics and Space Administration — The MAT3FECHM or tavg3_3d_chm_Fe data product is the MERRA Data Assimilation System Chemistry 3-Dimensional chemistry on layers edges that is time averaged, 3D model...

Towards Automatic Semantic Labelling of 3D City Models

Science.gov (United States)

Rook, M.; Biljecki, F.; Diakité, A. A.

2016-10-01

The lack of semantic information in many 3D city models is a considerable limiting factor in their use, as a lot of applications rely on semantics. Such information is not always available, since it is not collected at all times, it might be lost due to data transformation, or its lack may be caused by non-interoperability in data integration from other sources. This research is a first step in creating an automatic workflow that semantically labels plain 3D city model represented by a soup of polygons, with semantic and thematic information, as defined in the CityGML standard. The first step involves the reconstruction of the topology, which is used in a region growing algorithm that clusters upward facing adjacent triangles. Heuristic rules, embedded in a decision tree, are used to compute a likeliness score for these regions that either represent the ground (terrain) or a RoofSurface. Regions with a high likeliness score, to one of the two classes, are used to create a decision space, which is used in a support vector machine (SVM). Next, topological relations are utilised to select seeds that function as a start in a region growing algorithm, to create regions of triangles of other semantic classes. The topological relationships of the regions are used in the aggregation of the thematic building features. Finally, the level of detail is detected to generate the correct output in CityGML. The results show an accuracy between 85 % and 99 % in the automatic semantic labelling on four different test datasets. The paper is concluded by indicating problems and difficulties implying the next steps in the research.

Crystal and magnetic structures of CaCu3Fe4O12 and LaCu3Fe4O12: distinct charge transitions of unusual high valence Fe

International Nuclear Information System (INIS)

Shimakawa, Yuichi

2015-01-01

New 134-type perovskites, CaCu 3 Fe 4 O 12 (CCFO) and LaCu 3 Fe 4 O 12 (LCFO), were prepared by means of high-pressure synthesis. The compounds contain unusual high valence Fe 4+ in CCFO and Fe 3.75+ in LCFO at high temperatures. With decreasing temperature, the instabilities of the high valence states of Fe are relieved by distinct charge transitions, which are charge disproportionation (4Fe 4+   →  2Fe 3+   +  2Fe 5+ ) in CCFO and intermetallic charge transfer (3Cu 2+   +  4Fe 3.75+   →  3Cu 3+   +  4Fe 3+ ) in LCFO. Crystal structure analysis with synchrotron x-ray diffraction and magnetic structure analysis with neutron diffraction revealed the nature of the transitions. Although the two behaviors look completely different from each other in simple ionic models, they can both be explained by the localization of ligand holes, which are produced by the strong hybridization of low-lying Fe-d and oxygen p orbitals in the oxides. The ligand holes in the charge disproportionated CCFO are localized at the Fe–O sites alternately (4d 5 L  →  2d 5   +  2d 5 L 2 ) and the ligand holes in the charge transferred LCFO are localized at the Cu–O sites (3d 9   +  4d 5 L 0.75   →  3d 9 L  +  4d 5 ). (review)

Automatic slice identification in 3D medical images with a ConvNet regressor

NARCIS (Netherlands)

de Vos, Bob D.; Viergever, Max A.; de Jong, Pim A.; Išgum, Ivana

2016-01-01

Identification of anatomical regions of interest is a prerequisite in many medical image analysis tasks. We propose a method that automatically identifies a slice of interest (SOI) in 3D images with a convolutional neural network (ConvNet) regressor. In 150 chest CT scans two reference slices were

Fabrication of highly oriented D03-Fe3Si nanocrystals by solid-state dewetting of Si ultrathin layer

International Nuclear Information System (INIS)

Naito, Muneyuki; Nakagawa, Tatsuhiko; Machida, Nobuya; Shigematsu, Toshihiko; Nakao, Motoi; Sudoh, Koichi

2013-01-01

In this paper, highly oriented nanocrystals of Fe 3 Si with a D0 3 structure are fabricated on SiO 2 using ultrathin Si on insulator substrate. First, (001) oriented Si nanocrystals are formed on the SiO 2 layer by solid state dewetting of the top Si layer. Then, Fe addition to the Si nanocrystals is performed by reactive deposition epitaxy and post-deposition annealing at 500 °C. The structures of the Fe–Si nanocrystals are analyzed by cross-sectional transmission electron microscopy and nanobeam electron diffraction. We observe that Fe 3 Si nanocrystals with D0 3 , B2, and A2 structures coexist on the 1-h post-annealed samples. Prolonged annealing at 500 °C is effective in obtaining Fe 3 Si nanocrystals with a D0 3 single phase, thereby promoting structural ordering in the nanocrystals. We discuss the formation process of the highly oriented D0 3 -Fe 3 Si nanocrystals on the basis of the atomistic structural information. - Highlights: • Highly oriented Fe–Si nanocrystals (NCs) are fabricated by reactive deposition. • Si NCs formed by solid state dewetting of Si thin layers are used as seed crystals. • The structures of Fe–Si NCs are analyzed by nanobeam electron diffraction. • Most of Fe–Si NCs possess the D0 3 structure after post-deposition annealing

Automatic Generation of 3D Caricatures Based on Artistic Deformation Styles.

Science.gov (United States)

Clarke, Lyndsey; Chen, Min; Mora, Benjamin

2011-06-01

Caricatures are a form of humorous visual art, usually created by skilled artists for the intention of amusement and entertainment. In this paper, we present a novel approach for automatic generation of digital caricatures from facial photographs, which capture artistic deformation styles from hand-drawn caricatures. We introduced a pseudo stress-strain model to encode the parameters of an artistic deformation style using "virtual" physical and material properties. We have also developed a software system for performing the caricaturistic deformation in 3D which eliminates the undesirable artifacts in 2D caricaturization. We employed a Multilevel Free-Form Deformation (MFFD) technique to optimize a 3D head model reconstructed from an input facial photograph, and for controlling the caricaturistic deformation. Our results demonstrated the effectiveness and usability of the proposed approach, which allows ordinary users to apply the captured and stored deformation styles to a variety of facial photographs.

An Efficient Multimodal 2D + 3D Feature-based Approach to Automatic Facial Expression Recognition

KAUST Repository

Li, Huibin

2015-07-29

We present a fully automatic multimodal 2D + 3D feature-based facial expression recognition approach and demonstrate its performance on the BU-3DFE database. Our approach combines multi-order gradient-based local texture and shape descriptors in order to achieve efficiency and robustness. First, a large set of fiducial facial landmarks of 2D face images along with their 3D face scans are localized using a novel algorithm namely incremental Parallel Cascade of Linear Regression (iPar-CLR). Then, a novel Histogram of Second Order Gradients (HSOG) based local image descriptor in conjunction with the widely used first-order gradient based SIFT descriptor are used to describe the local texture around each 2D landmark. Similarly, the local geometry around each 3D landmark is described by two novel local shape descriptors constructed using the first-order and the second-order surface differential geometry quantities, i.e., Histogram of mesh Gradients (meshHOG) and Histogram of mesh Shape index (curvature quantization, meshHOS). Finally, the Support Vector Machine (SVM) based recognition results of all 2D and 3D descriptors are fused at both feature-level and score-level to further improve the accuracy. Comprehensive experimental results demonstrate that there exist impressive complementary characteristics between the 2D and 3D descriptors. We use the BU-3DFE benchmark to compare our approach to the state-of-the-art ones. Our multimodal feature-based approach outperforms the others by achieving an average recognition accuracy of 86.32%. Moreover, a good generalization ability is shown on the Bosphorus database.

An Efficient Multimodal 2D + 3D Feature-based Approach to Automatic Facial Expression Recognition

KAUST Repository

Li, Huibin; Ding, Huaxiong; Huang, Di; Wang, Yunhong; Zhao, Xi; Morvan, Jean-Marie; Chen, Liming

2015-01-01

We present a fully automatic multimodal 2D + 3D feature-based facial expression recognition approach and demonstrate its performance on the BU-3DFE database. Our approach combines multi-order gradient-based local texture and shape descriptors in order to achieve efficiency and robustness. First, a large set of fiducial facial landmarks of 2D face images along with their 3D face scans are localized using a novel algorithm namely incremental Parallel Cascade of Linear Regression (iPar-CLR). Then, a novel Histogram of Second Order Gradients (HSOG) based local image descriptor in conjunction with the widely used first-order gradient based SIFT descriptor are used to describe the local texture around each 2D landmark. Similarly, the local geometry around each 3D landmark is described by two novel local shape descriptors constructed using the first-order and the second-order surface differential geometry quantities, i.e., Histogram of mesh Gradients (meshHOG) and Histogram of mesh Shape index (curvature quantization, meshHOS). Finally, the Support Vector Machine (SVM) based recognition results of all 2D and 3D descriptors are fused at both feature-level and score-level to further improve the accuracy. Comprehensive experimental results demonstrate that there exist impressive complementary characteristics between the 2D and 3D descriptors. We use the BU-3DFE benchmark to compare our approach to the state-of-the-art ones. Our multimodal feature-based approach outperforms the others by achieving an average recognition accuracy of 86.32%. Moreover, a good generalization ability is shown on the Bosphorus database.

Automatic airline baggage counting using 3D image segmentation

Science.gov (United States)

Yin, Deyu; Gao, Qingji; Luo, Qijun

2017-06-01

The baggage number needs to be checked automatically during baggage self-check-in. A fast airline baggage counting method is proposed in this paper using image segmentation based on height map which is projected by scanned baggage 3D point cloud. There is height drop in actual edge of baggage so that it can be detected by the edge detection operator. And then closed edge chains are formed from edge lines that is linked by morphological processing. Finally, the number of connected regions segmented by closed chains is taken as the baggage number. Multi-bag experiment that is performed on the condition of different placement modes proves the validity of the method.

Fe3O4/C composite with hollow spheres in porous 3D-nanostructure as anode material for the lithium-ion batteries

Science.gov (United States)

Yang, Zhao; Su, Danyang; Yang, Jinping; Wang, Jing

2017-09-01

3d transition-metal oxides, especially Fe3O4, as anode materials for the lithium-ion batteries have been attracting intensive attentions in recent years due to their high energy capacity and low toxicity. A new Fe3O4/C composite with hollow spheres in porous three-dimensional (3D) nanostructure, which was synthesized by a facile solvothermal method using FeCl3·6H2O and porous spongy carbon as raw materials. The specific surface area and microstructures of composite were characterized by nitrogen adsorption-desorption isotherm method, FE-SEM and HR-TEM. A homogeneous distribution of hollow Fe3O4 spheres (diameter ranges from 120 nm to 150 nm) in the spongy carbon (pore size > 200 nm) conductive 3D-network significantly reduced the lithium-ion diffusion length and increased the electrochemical reaction area, and further more enhanced the lithium ion battery performance, such as discharge capacity and cycle life. As an anode material for the lithium-ion battery, the title composite exhibit excellent electrochemical properties. The Fe3O4/C composite electrode achieved a relatively high reversible specific capacity of 1450.1 mA h g-1 in the first cycle at 100 mA g-1, and excellent rate capability (69% retention at 1000 mA g-1) with good cycle stability (only 10% loss after 100 cycles).

3D automatic anatomy segmentation based on iterative graph-cut-ASM.

Science.gov (United States)

Chen, Xinjian; Bagci, Ulas

2011-08-01

This paper studies the feasibility of developing an automatic anatomy segmentation (AAS) system in clinical radiology and demonstrates its operation on clinical 3D images. The AAS system, the authors are developing consists of two main parts: object recognition and object delineation. As for recognition, a hierarchical 3D scale-based multiobject method is used for the multiobject recognition task, which incorporates intensity weighted ball-scale (b-scale) information into the active shape model (ASM). For object delineation, an iterative graph-cut-ASM (IGCASM) algorithm is proposed, which effectively combines the rich statistical shape information embodied in ASM with the globally optimal delineation capability of the GC method. The presented IGCASM algorithm is a 3D generalization of the 2D GC-ASM method that they proposed previously in Chen et al. [Proc. SPIE, 7259, 72590C1-72590C-8 (2009)]. The proposed methods are tested on two datasets comprised of images obtained from 20 patients (10 male and 10 female) of clinical abdominal CT scans, and 11 foot magnetic resonance imaging (MRI) scans. The test is for four organs (liver, left and right kidneys, and spleen) segmentation, five foot bones (calcaneus, tibia, cuboid, talus, and navicular). The recognition and delineation accuracies were evaluated separately. The recognition accuracy was evaluated in terms of translation, rotation, and scale (size) error. The delineation accuracy was evaluated in terms of true and false positive volume fractions (TPVF, FPVF). The efficiency of the delineation method was also evaluated on an Intel Pentium IV PC with a 3.4 GHZ CPU machine. The recognition accuracies in terms of translation, rotation, and scale error over all organs are about 8 mm, 10 degrees and 0.03, and over all foot bones are about 3.5709 mm, 0.35 degrees and 0.025, respectively. The accuracy of delineation over all organs for all subjects as expressed in TPVF and FPVF is 93.01% and 0.22%, and all foot bones for

3D automatic anatomy segmentation based on iterative graph-cut-ASM

International Nuclear Information System (INIS)

Chen, Xinjian; Bagci, Ulas

2011-01-01

Purpose: This paper studies the feasibility of developing an automatic anatomy segmentation (AAS) system in clinical radiology and demonstrates its operation on clinical 3D images. Methods: The AAS system, the authors are developing consists of two main parts: object recognition and object delineation. As for recognition, a hierarchical 3D scale-based multiobject method is used for the multiobject recognition task, which incorporates intensity weighted ball-scale (b-scale) information into the active shape model (ASM). For object delineation, an iterative graph-cut-ASM (IGCASM) algorithm is proposed, which effectively combines the rich statistical shape information embodied in ASM with the globally optimal delineation capability of the GC method. The presented IGCASM algorithm is a 3D generalization of the 2D GC-ASM method that they proposed previously in Chen et al.[Proc. SPIE, 7259, 72590C1-72590C-8 (2009)]. The proposed methods are tested on two datasets comprised of images obtained from 20 patients (10 male and 10 female) of clinical abdominal CT scans, and 11 foot magnetic resonance imaging (MRI) scans. The test is for four organs (liver, left and right kidneys, and spleen) segmentation, five foot bones (calcaneus, tibia, cuboid, talus, and navicular). The recognition and delineation accuracies were evaluated separately. The recognition accuracy was evaluated in terms of translation, rotation, and scale (size) error. The delineation accuracy was evaluated in terms of true and false positive volume fractions (TPVF, FPVF). The efficiency of the delineation method was also evaluated on an Intel Pentium IV PC with a 3.4 GHZ CPU machine. Results: The recognition accuracies in terms of translation, rotation, and scale error over all organs are about 8 mm, 10 deg. and 0.03, and over all foot bones are about 3.5709 mm, 0.35 deg. and 0.025, respectively. The accuracy of delineation over all organs for all subjects as expressed in TPVF and FPVF is 93.01% and 0.22%, and

CuFeO2 formation using fused deposition modeling 3D printing and sintering technique

Science.gov (United States)

Salea, A.; Dasaesamoh, A.; Prathumwan, R.; Kongkaew, T.; Subannajui, K.

2017-09-01

CuFeO2 is a metal oxide mineral material which is called delafossite. It can potentially be used as a chemical catalyst, and gas sensing material. There are methods to fabricate CuFeO2 such as chemical synthesis, sintering, sputtering, and chemical vapor deposition. In our work, CuFeO2 is prepared by Fused Deposition Modeling (FDM) 3D printing. The composite filament which composed of Cu and Fe elements is printed in three dimensions, and then sintered and annealed at high temperature to obtain CuFeO2. Suitable polymer blend and maximum percent volume of metal powder are studied. When percent volume of metal powder is increased, melt flow rate of polymer blend is also increased. The most suitable printing condition is reported and the properties of CuFeO2 are observed by Scanning Electron Microscopy, and Dynamic Scanning Calorimeter, X-ray diffraction. As a new method to produce semiconductor, this technique has a potential to allow any scientist or students to design and print a catalyst or sensing material by the most conventional 3D printing machine which is commonly used around the world.

Fast automatic 3D liver segmentation based on a three-level AdaBoost-guided active shape model

Energy Technology Data Exchange (ETDEWEB)

He, Baochun; Huang, Cheng; Zhou, Shoujun; Hu, Qingmao; Jia, Fucang, E-mail: fc.jia@siat.ac.cn [Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055 (China); Sharp, Gregory [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts 02114 (United States); Fang, Chihua; Fan, Yingfang [Department of Hepatology (I), Zhujiang Hospital, Southern Medical University, Guangzhou 510280 (China)

2016-05-15

Purpose: A robust, automatic, and rapid method for liver delineation is urgently needed for the diagnosis and treatment of liver disorders. Until now, the high variability in liver shape, local image artifacts, and the presence of tumors have complicated the development of automatic 3D liver segmentation. In this study, an automatic three-level AdaBoost-guided active shape model (ASM) is proposed for the segmentation of the liver based on enhanced computed tomography images in a robust and fast manner, with an emphasis on the detection of tumors. Methods: The AdaBoost voxel classifier and AdaBoost profile classifier were used to automatically guide three-level active shape modeling. In the first level of model initialization, fast automatic liver segmentation by an AdaBoost voxel classifier method is proposed. A shape model is then initialized by registration with the resulting rough segmentation. In the second level of active shape model fitting, a prior model based on the two-class AdaBoost profile classifier is proposed to identify the optimal surface. In the third level, a deformable simplex mesh with profile probability and curvature constraint as the external force is used to refine the shape fitting result. In total, three registration methods—3D similarity registration, probability atlas B-spline, and their proposed deformable closest point registration—are used to establish shape correspondence. Results: The proposed method was evaluated using three public challenge datasets: 3Dircadb1, SLIVER07, and Visceral Anatomy3. The results showed that our approach performs with promising efficiency, with an average of 35 s, and accuracy, with an average Dice similarity coefficient (DSC) of 0.94 ± 0.02, 0.96 ± 0.01, and 0.94 ± 0.02 for the 3Dircadb1, SLIVER07, and Anatomy3 training datasets, respectively. The DSC of the SLIVER07 testing and Anatomy3 unseen testing datasets were 0.964 and 0.933, respectively. Conclusions: The proposed automatic approach

Fast automatic 3D liver segmentation based on a three-level AdaBoost-guided active shape model.

Science.gov (United States)

He, Baochun; Huang, Cheng; Sharp, Gregory; Zhou, Shoujun; Hu, Qingmao; Fang, Chihua; Fan, Yingfang; Jia, Fucang

2016-05-01

A robust, automatic, and rapid method for liver delineation is urgently needed for the diagnosis and treatment of liver disorders. Until now, the high variability in liver shape, local image artifacts, and the presence of tumors have complicated the development of automatic 3D liver segmentation. In this study, an automatic three-level AdaBoost-guided active shape model (ASM) is proposed for the segmentation of the liver based on enhanced computed tomography images in a robust and fast manner, with an emphasis on the detection of tumors. The AdaBoost voxel classifier and AdaBoost profile classifier were used to automatically guide three-level active shape modeling. In the first level of model initialization, fast automatic liver segmentation by an AdaBoost voxel classifier method is proposed. A shape model is then initialized by registration with the resulting rough segmentation. In the second level of active shape model fitting, a prior model based on the two-class AdaBoost profile classifier is proposed to identify the optimal surface. In the third level, a deformable simplex mesh with profile probability and curvature constraint as the external force is used to refine the shape fitting result. In total, three registration methods-3D similarity registration, probability atlas B-spline, and their proposed deformable closest point registration-are used to establish shape correspondence. The proposed method was evaluated using three public challenge datasets: 3Dircadb1, SLIVER07, and Visceral Anatomy3. The results showed that our approach performs with promising efficiency, with an average of 35 s, and accuracy, with an average Dice similarity coefficient (DSC) of 0.94 ± 0.02, 0.96 ± 0.01, and 0.94 ± 0.02 for the 3Dircadb1, SLIVER07, and Anatomy3 training datasets, respectively. The DSC of the SLIVER07 testing and Anatomy3 unseen testing datasets were 0.964 and 0.933, respectively. The proposed automatic approach achieves robust, accurate, and fast liver

Automatic localization of the da Vinci surgical instrument tips in 3-D transrectal ultrasound.

Science.gov (United States)

Mohareri, Omid; Ramezani, Mahdi; Adebar, Troy K; Abolmaesumi, Purang; Salcudean, Septimiu E

2013-09-01

Robot-assisted laparoscopic radical prostatectomy (RALRP) using the da Vinci surgical system is the current state-of-the-art treatment option for clinically confined prostate cancer. Given the limited field of view of the surgical site in RALRP, several groups have proposed the integration of transrectal ultrasound (TRUS) imaging in the surgical workflow to assist with accurate resection of the prostate and the sparing of the neurovascular bundles (NVBs). We previously introduced a robotic TRUS manipulator and a method for automatically tracking da Vinci surgical instruments with the TRUS imaging plane, in order to facilitate the integration of intraoperative TRUS in RALRP. Rapid and automatic registration of the kinematic frames of the da Vinci surgical system and the robotic TRUS probe manipulator is a critical component of the instrument tracking system. In this paper, we propose a fully automatic registration technique based on automatic 3-D TRUS localization of robot instrument tips pressed against the air-tissue boundary anterior to the prostate. The detection approach uses a multiscale filtering technique to identify and localize surgical instrument tips in the TRUS volume, and could also be used to detect other surface fiducials in 3-D ultrasound. Experiments have been performed using a tissue phantom and two ex vivo tissue samples to show the feasibility of the proposed methods. Also, an initial in vivo evaluation of the system has been carried out on a live anaesthetized dog with a da Vinci Si surgical system and a target registration error (defined as the root mean square distance of corresponding points after registration) of 2.68 mm has been achieved. Results show this method's accuracy and consistency for automatic registration of TRUS images to the da Vinci surgical system.

Automatic generation of medium-detailed 3D models of buildings based on CAD data

NARCIS (Netherlands)

Dominguez-Martin, B.; Van Oosterom, P.; Feito-Higueruela, F.R.; Garcia-Fernandez, A.L.; Ogayar-Anguita, C.J.

2015-01-01

We present the preliminary results of a work in progress which aims to obtain a software system able to automatically generate a set of diverse 3D building models with a medium level of detail, that is, more detailed that a mere parallelepiped, but not as detailed as a complete geometric

3D Fe{sub 2}(MoO{sub 4}){sub 3} microspheres with nanosheet constituents as high-capacity anode materials for lithium-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Zheng, Hao; Wang, Shiqiang [Hubei University, Key Laboratory for Synthesis and Applications of Organic Functional Molecules (China); Wang, Jiazhao; Wang, Jun [University of Wollongong, Institute for Superconducting and Electronic Materials (Australia); Li, Lin; Yang, Yun; Feng, Chuanqi, E-mail: cfeng@hubu.edu.cn [Hubei University, Key Laboratory for Synthesis and Applications of Organic Functional Molecules (China); Sun, Ziqi, E-mail: ziqi.sun@qut.edu.au [Queensland University of Technology, School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty (Australia)

2015-11-15

Three-dimensional (3D) Fe{sub 2}(MoO{sub 4}){sub 3} microspheres with ultrathin nanosheet constituents are first synthesized as anode materials for the lithium-ion battery. It is interesting that the single-crystalline nanosheets allow rapid electron/ion transport on the inside, and the high porosity ensures fast diffusion of liquid electrolyte in energy storage applications. The electrochemical properties of Fe{sub 2}(MoO{sub 4}){sub 3} as anode demonstrates that 3D Fe{sub 2}(MoO{sub 4}){sub 3} microspheres deliver an initial capacity of 1855 mAh/g at a current density of 100 mA/g. Particularly, when the current density is increased to 800 mA/g, the reversible capacity of Fe{sub 2}(MoO{sub 4}){sub 3} anode still arrived at 456 mAh/g over 50 cycles. The large and reversible capacities and stable charge–discharge cycling performance indicate that Fe{sub 2}(MoO{sub 4}){sub 3} is a promising anode material for lithium battery applications.Graphical abstractThe electrochemical properties of Fe{sub 2}(MoO{sub 4}){sub 3} as anode demonstrates that 3D Fe{sub 2}(MoO{sub 4}){sub 3} microspheres delivered an initial capacity of 1855 mAh/g at a current density of 100 mA/g. When the current density was increased to 800 mA/g, the Fe{sub 2}(MoO{sub 4}){sub 3} still behaved high reversible capacity and good cycle performance.

Weighted f-values, A-values, and line strengths for the E1 transitions among 3d6, 3d54s, and 3d54p levels of Fe III

International Nuclear Information System (INIS)

Deb, Narayan C.; Hibbert, Alan

2009-01-01

Weighted oscillator strengths, weighted radiative rates, and line strengths for all the E1 transitions between 285 fine-structure levels belonging to the 3d 6 , 3d 5 4s, and 3d 5 4p configurations of Fe III are presented, in ascending order of wavelength. Calculations have been undertaken using the general configuration interaction (CI) code CIV3. The large configuration set is constructed by allowing single and double replacements from any of 3d 6 , 3d 5 4s, 3d 5 4p, and 3d 5 4d configurations to nl orbitals with n≤5,l≤3 as well as 6p. Additional selective promotions from 3s and 3p subshells are also included in the CI expansions to incorporate the important correlation effects in the n=3 shell. Results of some strong transitions between levels of 3d 6 , 3d 5 4s, and 3d 5 4p configurations are also presented and compared with other available calculations. It is found that large disagreements occur in many transitions among the existing calculations

3D FE simulation of PCMI (Pellet-Cladding Mechanical Interaction) considering frictionless contact

International Nuclear Information System (INIS)

Seo, Sang-Kyu; Lee, Sung-Uk; Lee, Eun-Ho; Yang, Dong-Yol; Kim, Hyo-Chan; Yang, Yong-Sik

2014-01-01

The goal of this code is coupling every aspect of physical phenomenon. Monodimensional FE model has been made for METEOR. It is good to evaluate the global behavior in high burn up levels. However, the multi-dimensional PCI analysis code is necessary to precisely analyze the stress distribution especially in case of the crack analysis. CAST3M 3D finite element code has been developed considering thermo-mechanical interaction in detail for TOUTATIS code. The advanced multidimensional code called ALCYONE has been developed considering chemical-physics and thermomechanical aspects. Although there are many codes that analyze pellet and cladding interaction, it is difficult to consider every physical aspect. In this paper, pellet to cladding mechanical interaction in 3D has been simulated with frictionless contact using the developed module, which is written in FORTRANN90. In this paper, 3D PCMI FE model is simulated with frictionless contact and elastic deformation. From the frictionless contact analysis, the interfacial pressure has been calculated and then this is used to obtain the solid heat coefficient which is a main factor to analyze the thermal distribution

Hepatic vessel segmentation for 3D planning of liver surgery experimental evaluation of a new fully automatic algorithm.

Science.gov (United States)

Conversano, Francesco; Franchini, Roberto; Demitri, Christian; Massoptier, Laurent; Montagna, Francesco; Maffezzoli, Alfonso; Malvasi, Antonio; Casciaro, Sergio

2011-04-01

The aim of this study was to identify the optimal parameter configuration of a new algorithm for fully automatic segmentation of hepatic vessels, evaluating its accuracy in view of its use in a computer system for three-dimensional (3D) planning of liver surgery. A phantom reproduction of a human liver with vessels up to the fourth subsegment order, corresponding to a minimum diameter of 0.2 mm, was realized through stereolithography, exploiting a 3D model derived from a real human computed tomographic data set. Algorithm parameter configuration was experimentally optimized, and the maximum achievable segmentation accuracy was quantified for both single two-dimensional slices and 3D reconstruction of the vessel network, through an analytic comparison of the automatic segmentation performed on contrast-enhanced computed tomographic phantom images with actual model features. The optimal algorithm configuration resulted in a vessel detection sensitivity of 100% for vessels > 1 mm in diameter, 50% in the range 0.5 to 1 mm, and 14% in the range 0.2 to 0.5 mm. An average area overlap of 94.9% was obtained between automatically and manually segmented vessel sections, with an average difference of 0.06 mm(2). The average values of corresponding false-positive and false-negative ratios were 7.7% and 2.3%, respectively. A robust and accurate algorithm for automatic extraction of the hepatic vessel tree from contrast-enhanced computed tomographic volume images was proposed and experimentally assessed on a liver model, showing unprecedented sensitivity in vessel delineation. This automatic segmentation algorithm is promising for supporting liver surgery planning and for guiding intraoperative resections. Copyright © 2011 AUR. Published by Elsevier Inc. All rights reserved.

3D FE Analysis of RC Beams Externally Strengthened with SRG/SRP Systems

Directory of Open Access Journals (Sweden)

Francesco Bencardino

2016-05-01

Full Text Available The purpose of this study is to evaluate, through a nonlinear Finite Element (FE analysis, the structural behavior of Reinforced Concrete (RC beams externally strengthened by using Steel Reinforced Grout (SRG and Steel Reinforced Polymer (SRP systems. The parameters taken into account were the external strengthening configuration, with or without U-wrap end anchorages, as well as the strengthening materials. The numerical simulations were carried out by using a three-dimensional (3D FE model. The linear and nonlinear behavior of all materials was modeled by appropriate constitutive laws and the connection between concrete substrate and external reinforcing layer was simulated by means of cohesive surfaces with appropriate bond-slip laws. In order to overcome convergence difficulties, to simulate the quasi-static response of the strengthened RC beams, a dynamic approach was adopted. The numerical results in terms of load-displacement curves, failure modes, and load and strain values at critical stages were validated against some experimental data. As a result, the proposed 3D FE model can be used to predict the structural behavior up to ultimate stage of similar strengthened beams without carrying out experimental tests.

Automatic extraction of discontinuity orientation from rock mass surface 3D point cloud

Science.gov (United States)

Chen, Jianqin; Zhu, Hehua; Li, Xiaojun

2016-10-01

This paper presents a new method for extracting discontinuity orientation automatically from rock mass surface 3D point cloud. The proposed method consists of four steps: (1) automatic grouping of discontinuity sets using an improved K-means clustering method, (2) discontinuity segmentation and optimization, (3) discontinuity plane fitting using Random Sample Consensus (RANSAC) method, and (4) coordinate transformation of discontinuity plane. The method is first validated by the point cloud of a small piece of a rock slope acquired by photogrammetry. The extracted discontinuity orientations are compared with measured ones in the field. Then it is applied to a publicly available LiDAR data of a road cut rock slope at Rockbench repository. The extracted discontinuity orientations are compared with the method proposed by Riquelme et al. (2014). The results show that the presented method is reliable and of high accuracy, and can meet the engineering needs.

Quasi-automatic 3D finite element model generation for individual single-rooted teeth and periodontal ligament.

Science.gov (United States)

Clement, R; Schneider, J; Brambs, H-J; Wunderlich, A; Geiger, M; Sander, F G

2004-02-01

The paper demonstrates how to generate an individual 3D volume model of a human single-rooted tooth using an automatic workflow. It can be implemented into finite element simulation. In several computational steps, computed tomography data of patients are used to obtain the global coordinates of the tooth's surface. First, the large number of geometric data is processed with several self-developed algorithms for a significant reduction. The most important task is to keep geometrical information of the real tooth. The second main part includes the creation of the volume model for tooth and periodontal ligament (PDL). This is realized with a continuous free form surface of the tooth based on the remaining points. Generating such irregular objects for numerical use in biomechanical research normally requires enormous manual effort and time. The finite element mesh of the tooth, consisting of hexahedral elements, is composed of different materials: dentin, PDL and surrounding alveolar bone. It is capable of simulating tooth movement in a finite element analysis and may give valuable information for a clinical approach without the restrictions of tetrahedral elements. The mesh generator of FE software ANSYS executed the mesh process for hexahedral elements successfully.

Fatigue of multiscale composites with secondary nanoplatelet reinforcement: 3D computational analysis

DEFF Research Database (Denmark)

Dai, Gaoming; Mishnaevsky, Leon, Jr.

2014-01-01

3D numerical simulations of fatigue damage of multiscale fiber reinforced polymer composites with secondary nanoclay reinforcement are carried out. Macro–micro FE models of the multiscale composites are generated automatically using Python based software. The effect of the nanoclay reinforcement....... Multiscale composites with exfoliated nanoreinforcement and aligned nanoplatelets ensure the better fatigue resistance than those with intercalated/clustered and randomly oriented nanoreinforcement....

Fragility of ferromagnetic double exchange interactions and pressure tuning of magnetism in 3 d -5 d double perovskite Sr2FeOsO6

Science.gov (United States)

Veiga, L. S. I.; Fabbris, G.; van Veenendaal, M.; Souza-Neto, N. M.; Feng, H. L.; Yamaura, K.; Haskel, D.

2015-06-01

The ability to tune exchange (magnetic) interactions between 3 d transition metals in perovskite structures has proven to be a powerful route to discovery of novel properties. Here we demonstrate that the introduction of 3 d -5 d exchange pathways in double perovskites enables additional tunability, a result of the large spatial extent of 5 d wave functions. Using x-ray probes of magnetism and structure at high pressure, we show that compression of Sr2FeOsO6 drives an unexpected continuous change in the sign of Fe-Os exchange interactions and a transition from antiferromagnetic to ferrimagnetic order. We analyze the relevant electron-electron interactions, shedding light into fundamental differences with the more thoroughly studied 3 d -3 d systems.

Octahedron Fe3O4 particles supported on 3D MWCNT/graphene foam: In-situ method and application as a comprehensive microwave absorption material

Science.gov (United States)

Shi, Luolin; Zhao, Yan; Li, Ye; Han, Xiao; Zhang, Tong

2017-09-01

In this work, we used in-situ method to directly prepare a novel structure consisting of well-distributed octahedron Fe3O4 particles, porous graphene foam (GF) and fibrous multiwalled carbon nanotube (MWCNT): started with an intense stir to anchor Fe3+ on the surfaces of graphene oxide and oxided MWCNT, followed by solvothermal reaction to synthesize 3D lightweight Fe3O4/MWCNT/GF hybrids with high performance microwave absorption (MA). The maximum Reflection Loss (RL) value of -35.30 dB and 9.01 GHz bandwidth with RL below -10 dB detected with the thickness of 3.0 mm are achieved by Fe3O4/MWCNT/GF with an ultralow bulk density of 5.0 mg cm-3, of which the Specific Microwave Absorption Performance is much higher than most available MA materials reported. Impedance matching, high loss characteristic, interfacial polarization and polarization relaxation significantly improve MA properties, which serves as a guide for fabricating comprehensive MA materials enjoying numerous advantages of high RL value, broad bandwidth, low density and thin thickness.

Nonlinear Synchronization for Automatic Learning of 3D Pose Variability in Human Motion Sequences

Directory of Open Access Journals (Sweden)

Mozerov M

2010-01-01

Full Text Available A dense matching algorithm that solves the problem of synchronizing prerecorded human motion sequences, which show different speeds and accelerations, is proposed. The approach is based on minimization of MRF energy and solves the problem by using Dynamic Programming. Additionally, an optimal sequence is automatically selected from the input dataset to be a time-scale pattern for all other sequences. The paper utilizes an action specific model which automatically learns the variability of 3D human postures observed in a set of training sequences. The model is trained using the public CMU motion capture dataset for the walking action, and a mean walking performance is automatically learnt. Additionally, statistics about the observed variability of the postures and motion direction are also computed at each time step. The synchronized motion sequences are used to learn a model of human motion for action recognition and full-body tracking purposes.

Automatic Generation of Structural Building Descriptions from 3D Point Cloud Scans

DEFF Research Database (Denmark)

Ochmann, Sebastian; Vock, Richard; Wessel, Raoul

2013-01-01

We present a new method for automatic semantic structuring of 3D point clouds representing buildings. In contrast to existing approaches which either target the outside appearance like the facade structure or rather low-level geometric structures, we focus on the building’s interior using indoor...... scans to derive high-level architectural entities like rooms and doors. Starting with a registered 3D point cloud, we probabilistically model the affiliation of each measured point to a certain room in the building. We solve the resulting clustering problem using an iterative algorithm that relies...... on the estimated visibilities between any two locations within the point cloud. With the segmentation into rooms at hand, we subsequently determine the locations and extents of doors between adjacent rooms. In our experiments, we demonstrate the feasibility of our method by applying it to synthetic as well...

57Fe Moessbauer and magnetization study of the Th7Fe3 and the hydride Th7Fe3H/sub n/

International Nuclear Information System (INIS)

Viccaro, P.J.; Shenoy, G.K.; Dunlap, B.D.; Westlake, D.G.; Malik, S.K.; Wallace, W.E.

1978-01-01

Th 7 Fe 3 is known to be a Pauli paramagnet and to undergo a superconducting transition at 1.86K. Its hydride Th 7 Fe 3 H/sub n/ is shown to possess magnetic ordering. The 57 Fe saturated hyperfine field in the hydride is estimated to be aproximately 20kG. A positive isomer shift of 0.30 +- 0.02 mm/s at 300 K relative to Th 7 Fe 3 would be consistent with an increase in d-like electrons on Fe. Preliminary magnetization results indicate a magnetic moment of about 0.5 μ/sub B/ for the hydride and a transition temperature near 300 K

Electric-dipole allowed and intercombination transitions among the 3d5, 3d44s and 3d44p levels of Fe IV

International Nuclear Information System (INIS)

Deb, Narayan C.; Hibbert, Alan

2010-01-01

Oscillator strengths and transition rates for the electric-dipole (E1) allowed and intercombination transitions among 3d 5 , 3d 4 4s and 3d 4 4p levels of Fe IV are calculated using the CIV3 code of Hibbert and coworkers. Using the Hartree-Fock functions up to 3d orbitals we have also optimized 4s, 4p, 4d, 4f, 5s, 5p and 5d orbitals of which 4s and 4p are taken to be spectroscopic and the remaining orbitals represent corrections to the spectroscopic orbitals or the correlation effects. The J-dependent levels of 108 LS states are included in the calculation and the relativistic effects are accounted for via the Breit-Pauli operator. Configurations are chosen in two steps: (a) two promotions were allowed from the 3p, 3d, 4s and 4p subshells, using all the orbitals; and (b) selective promotions from the 3s subshell are included, but only to the 3s and 4s orbitals. The ab initio fine-structure levels are then fine tuned to reproduce observed energy levels as closely as possible, and the resulting wavefunctions are used to calculate oscillator strengths and transition rates for all possible E1 transitions. For many of these transitions, the present results show good agreement between the length and velocity forms while for some transitions, some large disagreements are found with other available results. The complete list of weighted oscillator strengths, transition rates, and line strengths for transitions among the fine structure levels of the three lowest configurations are presented in ascending order of wavelength.

Optimization of Sintering Time and Holding Time for 3D Printing of Fe-Based Metallic Glasses

Directory of Open Access Journals (Sweden)

Wenzheng Wu

2018-06-01

Full Text Available Fe-based metallic glasses are amorphous alloys with high strength, high hardness, and excellent corrosion resistance; however, the immaturity of processing methods has prevented their wide application in industrial production. Fe-based metallic glass parts were manufactured employing pneumatic injection additive manufacturing in this study. An evenly dispersed and stable Fe-based metallic glass powder slurry with a solids content of 50% was prepared firstly. Then the Fe-based metallic glass parts were printed. The printed parts were dried, debinded, and sintered for strengthening. The deformations of the printed parts and sintered parts relative to the original model were then analyzed by a 3D scanning reconstruction method. The slightly average bulging and sunken deformation of the printed parts and sintered parts confirmed the good printing accuracy of the pneumatic injection manufacture system. The effects of the sintering temperature and holding time on the properties of the sintered parts were studied. For a sintering temperature of 580 °C and holding time of 1 h, the surface quality of the sintered parts was better. The sintering of 3D-printed Fe-based metallic glass parts was preliminarily realized in this study, and the feasibility of preparing Fe-based metallic glass using pneumatic injection additive manufacture was verified.

Automatic extraction of Manhattan-World building masses from 3D laser range scans.

Science.gov (United States)

Vanegas, Carlos A; Aliaga, Daniel G; Benes, Bedrich

2012-10-01

We propose a novel approach for the reconstruction of urban structures from 3D point clouds with an assumption of Manhattan World (MW) building geometry; i.e., the predominance of three mutually orthogonal directions in the scene. Our approach works in two steps. First, the input points are classified according to the MW assumption into four local shape types: walls, edges, corners, and edge corners. The classified points are organized into a connected set of clusters from which a volume description is extracted. The MW assumption allows us to robustly identify the fundamental shape types, describe the volumes within the bounding box, and reconstruct visible and occluded parts of the sampled structure. We show results of our reconstruction that has been applied to several synthetic and real-world 3D point data sets of various densities and from multiple viewpoints. Our method automatically reconstructs 3D building models from up to 10 million points in 10 to 60 seconds.

Outstanding Li-storage performance of LiFePO4@MWCNTs cathode material with 3D network structure for lithium-ion batteries

Science.gov (United States)

Sun, Xiaodong; Zhang, Le

2018-05-01

In this work, the MWCNTs-decorated LiFePO4 microspheres (LiFePO4@MWCNTs) with a 3D network structure have been synthesized by a facile and efficient spray-drying approach followed by solid-state reaction in a reduction atmosphere. In the as-prepared composite, the MWCNTs around LiFePO4 nanoparticles can provide 3D conductive networks which greatly facilitate the transport of Li+-ion and electron during the electrochemical reaction. Compared to the pure LiFePO4 material, the LiFePO4@MWCNTs composite as cathode for lithium-ion batteries exhibits significantly improved Li-storage performance in terms of rate capability and cyclic stability. Therefore, we can speculate that the spray-drying approach is a promising route to prepare the high-performance electrode materials with 3D network structure for electrochemical energy storage.

N-Doped Dual Carbon-Confined 3D Architecture rGO/Fe3O4/AC Nanocomposite for High-Performance Lithium-Ion Batteries.

Science.gov (United States)

Ding, Ranran; Zhang, Jie; Qi, Jie; Li, Zhenhua; Wang, Chengyang; Chen, Mingming

2018-04-25

To address the issues of low electrical conductivity, sluggish lithiation kinetics and dramatic volume variation in Fe 3 O 4 anodes of lithium ion battery, herein, a double carbon-confined three-dimensional (3D) nanocomposite architecture was synthesized by an electrostatically assisted self-assembly strategy. In the constructed architecture, the ultrafine Fe 3 O 4 subunits (∼10 nm) self-organize to form nanospheres (NSs) that are fully coated by amorphous carbon (AC), formatting core-shell structural Fe 3 O 4 /AC NSs. By further encapsulation by reduced graphene oxide (rGO) layers, a constructed 3D architecture was built as dual carbon-confined rGO/Fe 3 O 4 /AC. Such structure restrains the adverse reaction of the electrolyte, improves the electronic conductivity and buffers the mechanical stress of the entire electrode, thus performing excellent long-term cycling stability (99.4% capacity retention after 465 cycles relevant to the second cycle at 5 A g -1 ). Kinetic analysis reveals that a dual lithium storage mechanism including a diffusion reaction mechanism and a surface capacitive behavior mechanism coexists in the composites. Consequently, the resulting rGO/Fe 3 O 4 /AC nanocomposite delivers a high reversible capacity (835.8 mA h g -1 for 300 cycles at 1 A g -1 ), as well as remarkable rate capability (436.7 mA h g -1 at 10 A g -1 ).

Performance evaluation of 2D and 3D deep learning approaches for automatic segmentation of multiple organs on CT images

Science.gov (United States)

Zhou, Xiangrong; Yamada, Kazuma; Kojima, Takuya; Takayama, Ryosuke; Wang, Song; Zhou, Xinxin; Hara, Takeshi; Fujita, Hiroshi

2018-02-01

The purpose of this study is to evaluate and compare the performance of modern deep learning techniques for automatically recognizing and segmenting multiple organ regions on 3D CT images. CT image segmentation is one of the important task in medical image analysis and is still very challenging. Deep learning approaches have demonstrated the capability of scene recognition and semantic segmentation on nature images and have been used to address segmentation problems of medical images. Although several works showed promising results of CT image segmentation by using deep learning approaches, there is no comprehensive evaluation of segmentation performance of the deep learning on segmenting multiple organs on different portions of CT scans. In this paper, we evaluated and compared the segmentation performance of two different deep learning approaches that used 2D- and 3D deep convolutional neural networks (CNN) without- and with a pre-processing step. A conventional approach that presents the state-of-the-art performance of CT image segmentation without deep learning was also used for comparison. A dataset that includes 240 CT images scanned on different portions of human bodies was used for performance evaluation. The maximum number of 17 types of organ regions in each CT scan were segmented automatically and compared to the human annotations by using ratio of intersection over union (IU) as the criterion. The experimental results demonstrated the IUs of the segmentation results had a mean value of 79% and 67% by averaging 17 types of organs that segmented by a 3D- and 2D deep CNN, respectively. All the results of the deep learning approaches showed a better accuracy and robustness than the conventional segmentation method that used probabilistic atlas and graph-cut methods. The effectiveness and the usefulness of deep learning approaches were demonstrated for solving multiple organs segmentation problem on 3D CT images.

Role of temperature-dependent O-p-Fe-d hybridization parameter in the metal-insulator transition of Fe3O4: a theoretical study

Science.gov (United States)

Fauzi, A. D.; Majidi, M. A.; Rusydi, A.

2017-04-01

We propose a simple tight-binding based model for Fe3O4 that captures the preference of ferrimagnetic over ferromagnetic spin configuration of the system. Our model is consistent with previous theoretical and experimental studies suggesting that the system is half metallic, in which spin polarized electrons hop only among the Fe B sites. To address the metal-insulator transition (MIT) we propose that the strong correlation among electrons, which may also be influenced by the electron-phonon interactions, manifest as the temperature-dependence of the O-p-Fe-d hybridization parameter, particularly Fe-d belonging to one of the Fe B sites (denoted as {t}{{FeB}-{{O}}}(2)). By proposing that this parameter increases as the temperature decreases, our density-of-states calculation successfully captures a gap opening at the Fermi level, transforming the system from half metal to insulator. Within this model along with the corresponding choice of parameters and a certain profile of the temperature dependence of {t}{{FeB}-{{O}}}(2), we calculate the resistivity of the system as a function of temperature. Our calculation result reveals the drastic uprising trend of the resistivity profile as the temperature decreases, with the MIT transition temperature located around 100 K, which is in agreement with experimental data.

3D Convolutional Neural Network for Automatic Detection of Lung Nodules in Chest CT.

Science.gov (United States)

Hamidian, Sardar; Sahiner, Berkman; Petrick, Nicholas; Pezeshk, Aria

2017-01-01

Deep convolutional neural networks (CNNs) form the backbone of many state-of-the-art computer vision systems for classification and segmentation of 2D images. The same principles and architectures can be extended to three dimensions to obtain 3D CNNs that are suitable for volumetric data such as CT scans. In this work, we train a 3D CNN for automatic detection of pulmonary nodules in chest CT images using volumes of interest extracted from the LIDC dataset. We then convert the 3D CNN which has a fixed field of view to a 3D fully convolutional network (FCN) which can generate the score map for the entire volume efficiently in a single pass. Compared to the sliding window approach for applying a CNN across the entire input volume, the FCN leads to a nearly 800-fold speed-up, and thereby fast generation of output scores for a single case. This screening FCN is used to generate difficult negative examples that are used to train a new discriminant CNN. The overall system consists of the screening FCN for fast generation of candidate regions of interest, followed by the discrimination CNN.

3D micro-crack propagation simulation at enamel/adhesive interface using FE submodeling and element death techniques.

Science.gov (United States)

Liu, Heng-Liang; Lin, Chun-Li; Sun, Ming-Tsung; Chang, Yen-Hsiang

2010-06-01

This study investigates micro-crack propagation at the enamel/adhesive interface using finite element (FE) submodeling and element death techniques. A three-dimensional (3D) FE macro-model of the enamel/adhesive/ceramic subjected to shear bond testing was generated and analyzed. A 3D micro-model with interfacial bonding structure was constructed at the upper enamel/adhesive interface where the stress concentration was found from the macro-model results. The morphology of this interfacial bonding structure (i.e., resin tag) was assigned based on resin tag geometry and enamel rod arrangement from a scanning electron microscopy micrograph. The boundary conditions for the micro-model were determined from the macro-model results. A custom iterative code combined with the element death technique was used to calculate the micro-crack propagation. Parallel experiments were performed to validate this FE simulation. The stress concentration within the adhesive occurred mainly at the upper corner near the enamel/adhesive interface and the resin tag base. A simulated fracture path was found at the resin tag base along the enamel/adhesive interface. A morphological observation of the fracture patterns obtained from in vitro testing corresponded with the simulation results. This study shows that the FE submodeling and element death techniques could be used to simulate the 3D micro-stress pattern and the crack propagation noted at the enamel/adhesive interface.

Automatic seed picking for brachytherapy postimplant validation with 3D CT images.

Science.gov (United States)

Zhang, Guobin; Sun, Qiyuan; Jiang, Shan; Yang, Zhiyong; Ma, Xiaodong; Jiang, Haisong

2017-11-01

Postimplant validation is an indispensable part in the brachytherapy technique. It provides the necessary feedback to ensure the quality of operation. The ability to pick implanted seed relates directly to the accuracy of validation. To address it, an automatic approach is proposed for picking implanted brachytherapy seeds in 3D CT images. In order to pick seed configuration (location and orientation) efficiently, the approach starts with the segmentation of seed from CT images using a thresholding filter which based on gray-level histogram. Through the process of filtering and denoising, the touching seed and single seed are classified. The true novelty of this approach is found in the application of the canny edge detection and improved concave points matching algorithm to separate touching seeds. Through the computation of image moments, the seed configuration can be determined efficiently. Finally, two different experiments are designed to verify the performance of the proposed approach: (1) physical phantom with 60 model seeds, and (2) patient data with 16 cases. Through assessment of validated results by a medical physicist, the proposed method exhibited promising results. Experiment on phantom demonstrates that the error of seed location and orientation is within ([Formula: see text]) mm and ([Formula: see text])[Formula: see text], respectively. In addition, the most seed location and orientation error is controlled within 0.8 mm and 3.5[Formula: see text] in all cases, respectively. The average process time of seed picking is 8.7 s per 100 seeds. In this paper, an automatic, efficient and robust approach, performed on CT images, is proposed to determine the implanted seed location as well as orientation in a 3D workspace. Through the experiments with phantom and patient data, this approach also successfully exhibits good performance.

3D automatic segmentation method for retinal optical coherence tomography volume data using boundary surface enhancement

Directory of Open Access Journals (Sweden)

Yankui Sun

2016-03-01

Full Text Available With the introduction of spectral-domain optical coherence tomography (SD-OCT, much larger image datasets are routinely acquired compared to what was possible using the previous generation of time-domain OCT. Thus, there is a critical need for the development of three-dimensional (3D segmentation methods for processing these data. We present here a novel 3D automatic segmentation method for retinal OCT volume data. Briefly, to segment a boundary surface, two OCT volume datasets are obtained by using a 3D smoothing filter and a 3D differential filter. Their linear combination is then calculated to generate new volume data with an enhanced boundary surface, where pixel intensity, boundary position information, and intensity changes on both sides of the boundary surface are used simultaneously. Next, preliminary discrete boundary points are detected from the A-Scans of the volume data. Finally, surface smoothness constraints and a dynamic threshold are applied to obtain a smoothed boundary surface by correcting a small number of error points. Our method can extract retinal layer boundary surfaces sequentially with a decreasing search region of volume data. We performed automatic segmentation on eight human OCT volume datasets acquired from a commercial Spectralis OCT system, where each volume of datasets contains 97 OCT B-Scan images with a resolution of 496×512 (each B-Scan comprising 512 A-Scans containing 496 pixels; experimental results show that this method can accurately segment seven layer boundary surfaces in normal as well as some abnormal eyes.

Self-assembly synthesis of 3D graphene-encapsulated hierarchical Fe3O4 nano-flower architecture with high lithium storage capacity and excellent rate capability

Science.gov (United States)

Ma, Yating; Huang, Jian; Lin, Liang; Xie, Qingshui; Yan, Mengyu; Qu, Baihua; Wang, Laisen; Mai, Liqiang; Peng, Dong-Liang

2017-10-01

Graphene-encapsulated hierarchical metal oxides architectures can efficiently combine the merits of graphene and hierarchical metal oxides, which are deemed as the potential anode material candidates for the next-generation lithium-ion batteries due to the synergistic effect between them. Herein, a cationic surfactant induced self-assembly method is developed to construct 3D Fe3O4@reduction graphene oxide (H-Fe3O4@RGO) hybrid architecture in which hierarchical Fe3O4 nano-flowers (H-Fe3O4) are intimately encapsulated by 3D graphene network. Each H-Fe3O4 particle is constituted of rod-shaped skeletons surrounded by petal-like nano-flakes that are made up of enormous nanoparticles. When tested as the anode material in lithium-ion batteries, a high reversible capacity of 2270 mA h g-1 after 460 cycles is achieved under a current density of 0.5 A g-1. More impressively, even tested at a large current density of 10 A g-1, a decent reversible capacity of 490 mA h g-1 can be retained, which is still higher than the theoretical capacity of traditional graphite anode, demonstrating the remarkable lithium storage properties. The reasons for the excellent electrochemical performance of H-Fe3O4@RGO electrode have been discussed in detail.

Automatic treatment of multiple wound coils in 3D finite element problems including multiply connected regions

Energy Technology Data Exchange (ETDEWEB)

Leonard, P.J.; Lai, H.C.; Eastham, J.F.; Al-Akayshee, Q.H. [Univ. of Bath (United Kingdom)

1996-05-01

This paper describes an efficient scheme for incorporating multiple wire wound coils into 3D finite element models. The scheme is based on the magnetic scalar representation with an additional basis for each coil. There are no restrictions on the topology of coils with respect to ferromagnetic and conductor regions. Reduced scalar regions and cuts are automatically generated.

Automatic intensity-based 3D-to-2D registration of CT volume and dual-energy digital radiography for the detection of cardiac calcification

Science.gov (United States)

Chen, Xiang; Gilkeson, Robert; Fei, Baowei

2007-03-01

We are investigating three-dimensional (3D) to two-dimensional (2D) registration methods for computed tomography (CT) and dual-energy digital radiography (DR) for the detection of coronary artery calcification. CT is an established tool for the diagnosis of coronary artery diseases (CADs). Dual-energy digital radiography could be a cost-effective alternative for screening coronary artery calcification. In order to utilize CT as the "gold standard" to evaluate the ability of DR images for the detection and localization of calcium, we developed an automatic intensity-based 3D-to-2D registration method for 3D CT volumes and 2D DR images. To generate digital rendering radiographs (DRR) from the CT volumes, we developed three projection methods, i.e. Gaussian-weighted projection, threshold-based projection, and average-based projection. We tested normalized cross correlation (NCC) and normalized mutual information (NMI) as similarity measurement. We used the Downhill Simplex method as the search strategy. Simulated projection images from CT were fused with the corresponding DR images to evaluate the localization of cardiac calcification. The registration method was evaluated by digital phantoms, physical phantoms, and clinical data sets. The results from the digital phantoms show that the success rate is 100% with mean errors of less 0.8 mm and 0.2 degree for both NCC and NMI. The registration accuracy of the physical phantoms is 0.34 +/- 0.27 mm. Color overlay and 3D visualization of the clinical data show that the two images are registered well. This is consistent with the improvement of the NMI values from 0.20 +/- 0.03 to 0.25 +/- 0.03 after registration. The automatic 3D-to-2D registration method is accurate and robust and may provide a useful tool to evaluate the dual-energy DR images for the detection of coronary artery calcification.

Wavelengths of the 3p-3d transitions of the Co- and Fe-like ions: The effects of electron correlation

International Nuclear Information System (INIS)

Chen, Mau Hsiung.

1987-01-01

The experimental observations of the 3p 6 3d 9 2 D - 3p 5 3d 10 2 p transitions of the Co-like ions and 3p 6 3d 8 3 F 4 - 3p 5 3d 9 3 F 3 of the Fe-like ions have recently been extended to highly charged ions of heavy elements up to uranium (Z = 92). A comparison between the observed energies and calculated values from the Dirac-Fock model indicated persistent discrepancies of 3 to 4 eV for all ions. Systematic multiconfiguration Dirac-Fock calculations for these transitions have been carried out with emphases on the effects of electron correlation. The previously found discrepancies theory and experiment have mostly removed after the inclusion of the electron-electron correlation effects in the theoretical calculations. 13 refs

Automatic registration using implicit shape representations: applications in intraoperative 3D rotational angiography to preoperative CTA registration

International Nuclear Information System (INIS)

Subramanian, Navneeth; Pichon, Eric; Solomon, Stephen B.

2009-01-01

A solution for automatic registration of 3D rotational angiography (XA) to CT/MR of the liver. Targeted for use in treatment planning of liver interventions. A shape-based approach to registration is proposed that does not require specification of landmarks nor is it prone to local minima like purely intensity-based registration methods. Through the use of vessel characteristics, accurate registration is possible even in the presence of deformations induced by catheters and respiratory motion. Registration was performed on eight pairs of multiphase CT angiography and 3D rotational digital angiography datasets. Quantitative validation of the registration accuracy using vessel landmarks was performed on these datasets. The validation study showed that the method has a registration error of 9.41±4.13 mm. In addition, the computation time is well below 60 s making it attractive for clinical application. A new method for fully automatic 3DXA to CT/MR image registration was developed and found to be efficient and accurate using clinically realistic datasets. (orig.)

Automatic detection of flaws in polymer insulators using 3D industrial tomography; Deteccao automatica de vazios em isoladores polimericos por tomografia industrial 3D

Energy Technology Data Exchange (ETDEWEB)

Godoi, Walmor Cardoso; Swinka-Filho, Vitoldo [Instituto de Tecnologia para o Desenvolvimento (LACTEC), Curitiba, PR (Brazil)], Emails: walmor@lactec.org.br, vitoldo@lactec.org.br; Geus, Klaus de [Companhia Paranaense de Energia (Copel), Curitiba, PR (Brazil)], Email: klaus@copel.com; Silva, Romeu Ricardo da [SENAI-RJ Solda (CTS/Solda), Rio de Janeiro, RJ (Brazil). Centro de Tecnologia], Email: rrdsilva@firjan.org.br

2009-10-15

This work presents a methodology for the automatic detection of flaws in polymer insulators using three-dimensional industrial computed tomography (CT), as well as results obtained in the context of power distribution networks. The CT slices were reconstructed using 180 digital radiographs (projections) acquired by a high resolution system (pixel dimension of 50 {mu}m x 50 {mu}m, a-Si). For the reconstruction of 3D CT, 50 {mu}m wide bit map slices were used. The Marching Cubes algorithm was used to perform the 3D reconstruction, using the Visualization Tool kit (VTK) library and the Java programming language (64 Bits Linux platform). Nine features were obtained from the reconstructed three-dimensional objects for the neural networks training. Results showed to be satisfactory. (author)

Strong 3D and 1D magnetism in hexagonal Fe-chalcogenides FeS and FeSe vs. weak magnetism in hexagonal FeTe.

Science.gov (United States)

Parker, David S

2017-06-13

We present a comparative theoretical study of the hexagonal forms of the Fe-chalcogenides FeS, FeSe and FeTe with their better known tetragonal forms. While the tetragonal forms exhibit only an incipient antiferromagnetism and experimentally show superconductivity when doped, the hexagonal forms of FeS and FeSe display a robust magnetism. We show that this strong magnetism arises from a van Hove singularity associated with the direct Fe-Fe c-axis chains in the generally more three-dimensional NiAs structure. We also find that hexagonal FeTe is much less magnetic than the other two hexagonal materials, so that unconventional magnetically-mediated superconductivity is possible, although a large T c value is unlikely.

Computed oscillator strengths and energy levels for Fe III, Fe IV, Fe V, and Fe VI with calculated wavelengths and wavelengths derived from established data

International Nuclear Information System (INIS)

Fawcett, B.C.

1989-01-01

Calculated weighted oscillator strengths are tabulated for spectral lines of Fe III, Fe IV, Fe V, and Fe VI. The lines belong to transition arrays 3d 6 -3d 5 4p and 3d 5 4s-3d 5 4p in Fe III, 3d 5 -3d 4 4p and 3d 4 4s-3d 4 4p in Fe IV, 3d 4 -3d 3 4p and 3d 3 4s-3d 3 4p in Fe V, and 3d 3 -3d 2 4p and 3d 2 4s-3d 2 4p in Fe VI. For the calculations, Slater parameters are optimized on the basis of minimizing the discrepancies between observed and computed wavelengths. Configuration interaction was included among the 3d n , 3d n-1 4s, 3d n-2 4s 2 , 3d n-1 4d, and 3d n-1 5s even configurations and among the 3d n-1 4p, 3d n-2 4s4p, and 3d n-1 5p odd configurations, with 3p 5 3d n+1 added for Fe VI. Calculated wavelengths are compared with observational data, and the compositions of energy levels are listed. This completes a series of similar computations for these complex configurations covering Fe I to Fe VI

A semi-automatic image-based close range 3D modeling pipeline using a multi-camera configuration.

Science.gov (United States)

Rau, Jiann-Yeou; Yeh, Po-Chia

2012-01-01

The generation of photo-realistic 3D models is an important task for digital recording of cultural heritage objects. This study proposes an image-based 3D modeling pipeline which takes advantage of a multi-camera configuration and multi-image matching technique that does not require any markers on or around the object. Multiple digital single lens reflex (DSLR) cameras are adopted and fixed with invariant relative orientations. Instead of photo-triangulation after image acquisition, calibration is performed to estimate the exterior orientation parameters of the multi-camera configuration which can be processed fully automatically using coded targets. The calibrated orientation parameters of all cameras are applied to images taken using the same camera configuration. This means that when performing multi-image matching for surface point cloud generation, the orientation parameters will remain the same as the calibrated results, even when the target has changed. Base on this invariant character, the whole 3D modeling pipeline can be performed completely automatically, once the whole system has been calibrated and the software was seamlessly integrated. Several experiments were conducted to prove the feasibility of the proposed system. Images observed include that of a human being, eight Buddhist statues, and a stone sculpture. The results for the stone sculpture, obtained with several multi-camera configurations were compared with a reference model acquired by an ATOS-I 2M active scanner. The best result has an absolute accuracy of 0.26 mm and a relative accuracy of 1:17,333. It demonstrates the feasibility of the proposed low-cost image-based 3D modeling pipeline and its applicability to a large quantity of antiques stored in a museum.

Strong 3D and 1D magnetism in hexagonal Fe-chalcogenides FeS and FeSe vs. weak magnetism in hexagonal FeTe

Energy Technology Data Exchange (ETDEWEB)

Parker, David S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-06-13

We present a comparative theoretical study of the hexagonal forms of the Fe-chalcogenides FeS, FeSe and FeTe with their better known tetragonal forms. While the tetragonal forms exhibit only an incipient antiferromagnetism and experimentally show superconductivity when doped, the hexagonal forms of FeS and FeSe display a robust magnetism. We show that this strong magnetism arises from a van Hove singularity associated with the direct Fe-Fe c-axis chains in the generally more three-dimensional NiAs structure. We also find that hexagonal FeTe is much less magnetic than the other two hexagonal materials, so that unconventional magnetically-mediated superconductivity is possible, although a large T_c value is unlikely.

Fabrication of α-Fe/Fe3C/Woodceramic Nanocomposite with Its Improved Microwave Absorption and Mechanical Properties

Directory of Open Access Journals (Sweden)

Weihong Zhou

2018-05-01

Full Text Available Furan resin and fir powder pretreated by FeCl3 and aqueous ammonia solution were used to fabricate α-Fe/Fe3C/woodceramic nanocomposite. The bands of the pretreated wood powder were characterized by Fourier transform infrared spectroscopy (FTIR. The structural characterization of the nanocomposites was performed by scanning electron microscopy (SEM and X-ray diffraction (XRD. The microwave absorption of the nanocomposites was measured by a vector network analyzer in the range of 2–18 GHz. The mechanical properties of the composites were also investigated. XRD and SEM results show that the α-Fe and Fe3C nanoparticles are in-situ generated and disperse in the matrix of the woodceramic. The diameters of these nanoparticles increase with the increasing of concentration of FeCl3 solution. The experimental results show that both the complex permittivity and the complex permeability of α-Fe/Fe3C/woodceramic nanocomposites increase as the concentration of FeCl3 solution increases. The composites pretreated with 0.60 mol·L−1 FeCl3 have the best absorption properties. The maximum value of reflection loss (RL at 3 mm thickness reaches −25.60 dB at 10.16 GHz and the bandwidth below −10 dB is about 2.5 GHz. Compared to woodceramic, the bending strength and compressive strength of α-Fe/Fe3C/woodceramic nanocomposites increase by 22.5% and 18.7% at most, respectively.

Automatic extraction of soft tissues from 3D MRI head images using model driven analysis

International Nuclear Information System (INIS)

Jiang, Hao; Yamamoto, Shinji; Imao, Masanao.

1995-01-01

This paper presents an automatic extraction system (called TOPS-3D : Top Down Parallel Pattern Recognition System for 3D Images) of soft tissues from 3D MRI head images by using model driven analysis algorithm. As the construction of system TOPS we developed, two concepts have been considered in the design of system TOPS-3D. One is the system having a hierarchical structure of reasoning using model information in higher level, and the other is a parallel image processing structure used to extract plural candidate regions for a destination entity. The new points of system TOPS-3D are as follows. (1) The TOPS-3D is a three-dimensional image analysis system including 3D model construction and 3D image processing techniques. (2) A technique is proposed to increase connectivity between knowledge processing in higher level and image processing in lower level. The technique is realized by applying opening operation of mathematical morphology, in which a structural model function defined in higher level by knowledge representation is immediately used to the filter function of opening operation as image processing in lower level. The system TOPS-3D applied to 3D MRI head images consists of three levels. First and second levels are reasoning part, and third level is image processing part. In experiments, we applied 5 samples of 3D MRI head images with size 128 x 128 x 128 pixels to the system TOPS-3D to extract the regions of soft tissues such as cerebrum, cerebellum and brain stem. From the experimental results, the system is robust for variation of input data by using model information, and the position and shape of soft tissues are extracted corresponding to anatomical structure. (author)

Effectiveness of Iron Ethylenediamine-N,N′-bis(hydroxyphenylacetic) Acid (o,o-EDDHA/Fe3+) Formulations with Different Ratios of Meso and d,l-Racemic Isomers as Iron Fertilizers

OpenAIRE

Alcañiz Lucas, Sara; Jordá Guijarro, Juana Dolores; Cerdán, Mar

2017-01-01

Two o,o-EDDHA/Fe3+ formulations (meso, 93.5% w/w of meso isomer; and d,l-racemic, 91.3% w/w of d,l-racemic mixture) were prepared, and their efficacy to avoid or to relieve iron deficiency in Fe-sufficient and Fe-deficient tomato plants grown on hydroponic solution was compared with that of the current o,o-EDDHA/Fe3+ formulations (50% of meso and d,l-racemic isomers). The effectiveness of the three o,o-EDDHA/Fe3+ formulations was different depending on the iron nutritional status of plants. T...

Flexible 3D Fe@VO2 core-shell mesh: A highly efficient and easy-recycling catalyst for the removal of organic dyes.

Science.gov (United States)

Li, Jing; Wang, Ruoqi; Su, Zhen; Zhang, Dandan; Li, Heping; Yan, Youwei

2018-10-01

Nowadays, it is extremely urgent to search for efficient and effective catalysts for water purification due to the severe worldwide water-contamination crises. Here, 3D Fe@VO 2 core-shell mesh, a highly efficient catalyst toward removal of organic dyes with excellent recycling ability in the dark is designed and developed for the first time. This novel core-shell structure is actually 304 stainless steel mesh coated by VO 2 , fabricated by an electrophoretic deposition method. In such a core-shell structure, Fe as the core allows much easier separation from the water, endowing the catalyst with a flexible property for easy recycling, while VO 2 as the shell is highly efficient in degradation of organic dyes with the addition of H 2 O 2 . More intriguingly, the 3D Fe@VO 2 core-shell mesh exhibits favorable performance across a wide pH range. The 3D Fe@VO 2 core-shell mesh can decompose organic dyes both in a light-free condition and under visible irradiation. The possible catalytic oxidation mechanism of Fe@VO 2 /H 2 O 2 system is also proposed in this work. Considering its facile fabrication, remarkable catalytic efficiency across a wide pH range, and easy recycling characteristic, the 3D Fe@VO 2 core-shell mesh is a newly developed high-performance catalyst for addressing the universal water crises. Copyright © 2018 Elsevier B.V. All rights reserved.

Calculation of the electronic and magnetic structures of 3d impurities in the Hcp Fe matrix; Calculo da estrutura eletronica e magnetica de impurezas 3d na matriz do Fe HCP

Energy Technology Data Exchange (ETDEWEB)

Franca, Fernando

1995-12-31

In this work we investigate the local magnetic properties and the electronic structure of HCP Fe, as well introducing transition metals atoms 3d (Cs, Ti, Cr, Mn, Co, Ni, Cu, Zn) in HCP iron matrix. We employed the discrete variational method (DVM), which is an orbital molecular method which incorporate the Hartree-Fock-Slater theory and the linear combination of atomic orbitals (LCAO), in the self-consistent charge approximation and the local density approximation of Von Barth and Hedin to the exchange-correlation potential. We used the embedded cluster model to investigate the electronic structure and the local magnetic properties for the central atom of a cluster of 27 atoms immersed in the microcrystal representing the HCP Fe. (author) 32 refs., 19 figs., 2 tabs.

VP-Nets : Efficient automatic localization of key brain structures in 3D fetal neurosonography.

Science.gov (United States)

Huang, Ruobing; Xie, Weidi; Alison Noble, J

2018-04-23

Three-dimensional (3D) fetal neurosonography is used clinically to detect cerebral abnormalities and to assess growth in the developing brain. However, manual identification of key brain structures in 3D ultrasound images requires expertise to perform and even then is tedious. Inspired by how sonographers view and interact with volumes during real-time clinical scanning, we propose an efficient automatic method to simultaneously localize multiple brain structures in 3D fetal neurosonography. The proposed View-based Projection Networks (VP-Nets), uses three view-based Convolutional Neural Networks (CNNs), to simplify 3D localizations by directly predicting 2D projections of the key structures onto three anatomical views. While designed for efficient use of data and GPU memory, the proposed VP-Nets allows for full-resolution 3D prediction. We investigated parameters that influence the performance of VP-Nets, e.g. depth and number of feature channels. Moreover, we demonstrate that the model can pinpoint the structure in 3D space by visualizing the trained VP-Nets, despite only 2D supervision being provided for a single stream during training. For comparison, we implemented two other baseline solutions based on Random Forest and 3D U-Nets. In the reported experiments, VP-Nets consistently outperformed other methods on localization. To test the importance of loss function, two identical models are trained with binary corss-entropy and dice coefficient loss respectively. Our best VP-Net model achieved prediction center deviation: 1.8 ± 1.4 mm, size difference: 1.9 ± 1.5 mm, and 3D Intersection Over Union (IOU): 63.2 ± 14.7% when compared to the ground truth. To make the whole pipeline intervention free, we also implement a skull-stripping tool using 3D CNN, which achieves high segmentation accuracy. As a result, the proposed processing pipeline takes a raw ultrasound brain image as input, and output a skull-stripped image with five detected key brain

Another Method of Building 2D Entropy to Realize Automatic Segmentation

International Nuclear Information System (INIS)

Zhang, Y F; Zhang, Y

2006-01-01

2D entropy formed during the process of building 2D histogram can realize automatic segmentation. Traditional method utilizes central pixel grey value and the others or all of pixels grey mean value in 4-neighbor to build 2D histogram. In fact, the change of the greyscale value between two ''invariable position vectors'' cannot represent the total characteristics among neighbour pixels very well. A new method is proposed which makes use of minimum grey value in the 4-neighbor and of maximum grey value in the 3x3 neighbour except pixels of the 4-neighbor. New method and traditional one are used in contrast to realize image automatic segmentation. The experimental results of the classical image prove the new method is effective

Fabrication of a 3D active mixer based on deformable Fe-doped PDMS cones with magnetic actuation

International Nuclear Information System (INIS)

Riahi, Mohammadreza; Alizadeh, Elaheh

2012-01-01

In this paper an active 3D mixer for lab-on-chip applications is presented. The micrometer size cone shape holes are ablated on a PMMA sheet utilizing a CO 2 laser. The holes are filled with Fe micro-particles and the whole structure is molded with PDMS which cause the Fe micro-particles to be trapped in a PDMS cone structure. These Fe-doped PDMS cones are placed in a PMMA micro-channel structure fabricated by CO 2 laser machining. By applying an external periodic magnetic field, the cones periodically bend in the micro-channel and stir the fluid. The fabrication method and the effect of the magnetic field on the bending of the cones with different aspect ratios is also discussed utilizing computer simulation. Doping the polymers with micro- and nano-metallic particles has been carried out by different research groups before, but according to our knowledge, application of such structures for the fabrication of a 3D active mixer has not been presented before. (paper)

Automatic balancing of 3D models

DEFF Research Database (Denmark)

Christiansen, Asger Nyman; Schmidt, Ryan; Bærentzen, Jakob Andreas

2014-01-01

3D printing technologies allow for more diverse shapes than are possible with molds and the cost of making just one single object is negligible compared to traditional production methods. However, not all shapes are suitable for 3D print. One of the remaining costs is therefore human time spent......, in these cases, we will apply a rotation of the object which only deforms the shape a little near the base. No user input is required but it is possible to specify manufacturing constraints related to specific 3D print technologies. Several models have successfully been balanced and printed using both polyjet...... is solved by creating cavities of air and distributing dense materials inside the model. Consequently, the surface is not deformed. However, printing materials with significantly different densities is often not possible and adding cavities of air is often not enough to make the model balance. Consequently...

Automatic re-contouring in 4D radiotherapy

International Nuclear Information System (INIS)

Lu, Weiguo; Olivera, Gustavo H; Chen, Quan; Chen, Ming-Li; Ruchala, Kenneth J

2006-01-01

Delineating regions of interest (ROIs) on each phase of four-dimensional (4D) computed tomography (CT) images is an essential step for 4D radiotherapy. The requirement of manual phase-by-phase contouring prohibits the routine use of 4D radiotherapy. This paper develops an automatic re-contouring algorithm that combines techniques of deformable registration and surface construction. ROIs are manually contoured slice-by-slice in the reference phase image. A reference surface is constructed based on these reference contours using a triangulated surface construction technique. The deformable registration technique provides the voxel-to-voxel mapping between the reference phase and the test phase. The vertices of the reference surface are displaced in accordance with the deformation map, resulting in a deformed surface. The new contours are reconstructed by cutting the deformed surface slice-by-slice along the transversal, sagittal or coronal direction. Since both the inputs and outputs of our automatic re-contouring algorithm are contours, it is relatively easy to cope with any treatment planning system. We tested our automatic re-contouring algorithm using a deformable phantom and 4D CT images of six lung cancer patients. The proposed algorithm is validated by visual inspections and quantitative comparisons of the automatic re-contours with both the gold standard segmentations and the manual contours. Based on the automatic delineated ROIs, changes of tumour and sensitive structures during respiration are quantitatively analysed. This algorithm could also be used to re-contour daily images for treatment evaluation and adaptive radiotherapy

Automatic calibration method of voxel size for cone-beam 3D-CT scanning system

International Nuclear Information System (INIS)

Yang Min; Wang Xiaolong; Wei Dongbo; Liu Yipeng; Meng Fanyong; Li Xingdong; Liu Wenli

2014-01-01

For a cone-beam three-dimensional computed tomography (3D-CT) scanning system, voxel size is an important indicator to guarantee the accuracy of data analysis and feature measurement based on 3D-CT images. Meanwhile, the voxel size changes with the movement of the rotary stage along X-ray direction. In order to realize the automatic calibration of the voxel size, a new and easily-implemented method is proposed. According to this method, several projections of a spherical phantom are captured at different imaging positions and the corresponding voxel size values are calculated by non-linear least-square fitting. Through these interpolation values, a linear equation is obtained that reflects the relationship between the voxel size and the rotary stage translation distance from its nominal zero position. Finally, the linear equation is imported into the calibration module of the 3D-CT scanning system. When the rotary stage is moving along X-ray direction, the accurate value of the voxel size is dynamically exported. The experimental results prove that this method meets the requirements of the actual CT scanning system, and has virtues of easy implementation and high accuracy. (authors)

Effectiveness of Iron Ethylenediamine-N,N'-bis(hydroxyphenylacetic) Acid (o,o-EDDHA/Fe3+) Formulations with Different Ratios of Meso and d,l-Racemic Isomers as Iron Fertilizers.

Science.gov (United States)

Alcañiz, Sara; Jordá, Juana D; Cerdán, Mar

2017-01-18

Two o,o-EDDHA/Fe 3+ formulations (meso, 93.5% w/w of meso isomer; and d,l-racemic, 91.3% w/w of d,l-racemic mixture) were prepared, and their efficacy to avoid or to relieve iron deficiency in Fe-sufficient and Fe-deficient tomato plants grown on hydroponic solution was compared with that of the current o,o-EDDHA/Fe 3+ formulations (50% of meso and d,l-racemic isomers). The effectiveness of the three o,o-EDDHA/Fe 3+ formulations was different depending on the iron nutritional status of plants. The three o,o-EDDHA/Fe 3+ formulations tested were effective in preventing iron chlorosis in healthy plants. However, the higher the meso concentration in the formulations, the higher the effectiveness in the recovery of iron chlorotic plants from iron deficiency. Accordingly, o,o-EDDHA/Fe 3+ formulations rich in meso isomer are recommended in hydroponic systems.

Automatic segmentation of MRI head images by 3-D region growing method which utilizes edge information

International Nuclear Information System (INIS)

Jiang, Hao; Suzuki, Hidetomo; Toriwaki, Jun-ichiro

1991-01-01

This paper presents a 3-D segmentation method that automatically extracts soft tissue from multi-sliced MRI head images. MRI produces a sequence of two-dimensional (2-D) images which contains three-dimensional (3-D) information of organs. To utilize such information we need effective algorithms to treat 3-D digital images and to extract organs and tissues of interest. We developed a method to extract the brain from MRI images which uses a region growing procedure and integrates information of uniformity of gray levels and information of the presence of edge segments in the local area around the pixel of interest. First we generate a kernel region which is a part of brain tissue by simple thresholding. Then we grow the region by means of a region growing algorithm under the control of 3-D edge existence to obtain the region of the brain. Our method is rather simple because it uses basic 3-D image processing techniques like spatial difference. It is robust for variation of gray levels inside a tissue since it also refers to the edge information in the process of region growing. Therefore, the method is flexible enough to be applicable to the segmentation of other images including soft tissues which have complicated shapes and fluctuation in gray levels. (author)

Electrophoretically-Deposited Nano-Fe3O4@carbon 3D Structure on Carbon Fiber as High-Performance Supercapacitors

Science.gov (United States)

Hajalilou, Abdollah; Etemadifar, Reza; Abbasi-Chianeh, Vahid; Abouzari-Lotf, Ebrahim

2018-05-01

Structural and electrochemical behaviors of electrophortically-deposited Fe3O4 and Fe3O4@C nanoparticles on carbon fiber (CF) were investigated. The nanoparticles were synthesized via a green-assisted hydrothermal route. The as-prepared samples were characterized by x-ray diffraction, transmission and scanning electron microscopies, Fourier transform infrared and UV-visible spectroscopies as well as by a vibration sample magnetometer. Surprisingly, the saturation magnetization (M s) of the Fe3O4@C ( 26.99 emu/g) was about 20% higher than that of Fe3O4 nanoparticles. A rather rectangular CV curve for both the elecrophortically-deposited Fe3O4 and Fe3O4@C on CF indicated the double-layer supercapacitor behavior of the samples. The synergistic effects of double shells improved the electrochemical behavior of Fe3O4@CF. The Fe3O4@C@CF composite exhibited a higher specific capacitance of 412 F g-1 at scan rate of 0.05 V/s compared to the Fe3O4@CF with a value of 193 F g-1. The superb electrochemical properties of Fe3O4@C@CF confirm their potential for applications as supercapacitors in the energy storage field.

Comparison of the solar photocatalytic activity of ZnO-Fe2O3 and ZnO-Fe(0) on 2,4-D degradation in a CPC reactor.

Science.gov (United States)

Maya-Treviño, M L; Villanueva-Rodríguez, M; Guzmán-Mar, J L; Hinojosa-Reyes, L; Hernández-Ramírez, A

2015-03-01

In this work a comparative study of the catalytic activity of ZnO-Fe2O3 and ZnO-Fe(0) 0.5 wt% materials was carried out in the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) as a commercial formulation Hierbamina®, using a compound parabolic collector (CPC) reactor. The catalysts were synthesized by the sol-gel method and characterized by X-ray diffraction, UV-Vis diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy. The textural properties of solids were determined from N2 adsorption isotherms using the Brunauer-Emmett-Teller (BET) method. The incorporation of Fe(0) onto ZnO was demonstrated by X-ray photoelectron spectroscopy analysis. The photocatalytic tests were performed at pH 7, using 10 mg L(-1) of herbicide and 0.5 g L(-1) of catalyst loading. The decay in herbicide concentration was followed by reversed-phase chromatography. A complete degradation of 2,4-D was achieved using ZnO-Fe(0) while 47% of herbicide removal was attained with ZnO-Fe2O3 mixed oxide for an accumulated energy QUV ≈ 2 kJ L(-1). The removal percentage of total organic carbon (TOC) during the solar photocatalytic process was superior using ZnO-Fe(0), achieving 45% compared to the 15% obtained with the mixed oxide catalyst.

The bonding character and magnetic properties of Fe3Al: Comparison between disordered and ordered alloy

International Nuclear Information System (INIS)

Fan Runhua; Qi Liang; Sun Kangning; Min Guanghui; Gong Hongyu

2006-01-01

Fe 3 Al with D0 3 -ordered structure is one of the few structural intermetallics that can be disordered using non-equilibrium processing techniques. The bonding and magnetic character of the stoichiometric Fe 3 Al, with D0 3 -ordered or disordered structure, have been studied using the empirical electron theory of solid and molecular (EET). It was found that the magnetic property is basically dictated by the chemical bonding. There is a change of the character of the interatomic bonds from 3d(Fe)-3p(Al) for the D0 3 -ordered Fe 3 Al to 4sp(Fe)-3p(Al) for the disordered Fe 3 Al. For the latter, while the Fe 3d electrons participating in bonding is reduced, the mean magnetic moment is increased

Automatic gallbladder segmentation using combined 2D and 3D shape features to perform volumetric analysis in native and secretin-enhanced MRCP sequences.

Science.gov (United States)

Gloger, Oliver; Bülow, Robin; Tönnies, Klaus; Völzke, Henry

2017-11-24

We aimed to develop the first fully automated 3D gallbladder segmentation approach to perform volumetric analysis in volume data of magnetic resonance (MR) cholangiopancreatography (MRCP) sequences. Volumetric gallbladder analysis is performed for non-contrast-enhanced and secretin-enhanced MRCP sequences. Native and secretin-enhanced MRCP volume data were produced with a 1.5-T MR system. Images of coronal maximum intensity projections (MIP) are used to automatically compute 2D characteristic shape features of the gallbladder in the MIP images. A gallbladder shape space is generated to derive 3D gallbladder shape features, which are then combined with 2D gallbladder shape features in a support vector machine approach to detect gallbladder regions in MRCP volume data. A region-based level set approach is used for fine segmentation. Volumetric analysis is performed for both sequences to calculate gallbladder volume differences between both sequences. The approach presented achieves segmentation results with mean Dice coefficients of 0.917 in non-contrast-enhanced sequences and 0.904 in secretin-enhanced sequences. This is the first approach developed to detect and segment gallbladders in MR-based volume data automatically in both sequences. It can be used to perform gallbladder volume determination in epidemiological studies and to detect abnormal gallbladder volumes or shapes. The positive volume differences between both sequences may indicate the quantity of the pancreatobiliary reflux.

Engineering 3D bicontinuous hierarchically macro-mesoporous LiFePO4/C nanocomposite for lithium storage with high rate capability and long cycle stability.

Science.gov (United States)

Zhang, Qian; Huang, Shao-Zhuan; Jin, Jun; Liu, Jing; Li, Yu; Wang, Hong-En; Chen, Li-Hua; Wang, Bin-Jie; Su, Bao-Lian

2016-05-16

A highly crystalline three dimensional (3D) bicontinuous hierarchically macro-mesoporous LiFePO4/C nanocomposite constructed by nanoparticles in the range of 50~100 nm via a rapid microwave assisted solvothermal process followed by carbon coating have been synthesized as cathode material for high performance lithium-ion batteries. The abundant 3D macropores allow better penetration of electrolyte to promote Li(+) diffusion, the mesopores provide more electrochemical reaction sites and the carbon layers outside LiFePO4 nanoparticles increase the electrical conductivity, thus ultimately facilitating reverse reaction of Fe(3+) to Fe(2+) and alleviating electrode polarization. In addition, the particle size in nanoscale can provide short diffusion lengths for the Li(+) intercalation-deintercalation. As a result, the 3D macro-mesoporous nanosized LiFePO4/C electrode exhibits excellent rate capability (129.1 mA h/g at 2 C; 110.9 mA h/g at 10 C) and cycling stability (87.2% capacity retention at 2 C after 1000 cycles, 76.3% at 5 C after 500 cycles and 87.8% at 10 C after 500 cycles, respectively), which are much better than many reported LiFePO4/C structures. Our demonstration here offers the opportunity to develop nanoscaled hierarchically porous LiFePO4/C structures for high performance lithium-ion batteries through microwave assisted solvothermal method.

Nanotextured Spikes of α-Fe2O3/NiFe2O4 Composite for Efficient Photoelectrochemical Oxidation of Water.

Science.gov (United States)

Hussain, Shabeeb; Tavakoli, Mohammad Mahdi; Waleed, Aashir; Virk, Umar Siddique; Yang, Shihe; Waseem, Amir; Fan, Zhiyong; Nadeem, Muhammad Arif

2018-03-27

We demonstrate for the first time the application of p-NiFe 2 O 4 /n-Fe 2 O 3 composite thin films as anode materials for light-assisted electrolysis of water. The p-NiFe 2 O 4 /n-Fe 2 O 3 composite thin films were deposited on planar fluorinated tin oxide (FTO)-coated glass as well as on 3D array of nanospike (NSP) substrates. The effect of substrate (planar FTO and 3D-NSP) and percentage change of each component (i.e., NiFe 2 O 4 and Fe 2 O 3 ) of composite was studied on photoelectrochemical (PEC) water oxidation reaction. This work also includes the performance comparison of p-NiFe 2 O 4 /n-Fe 2 O 3 composite (planar and NSP) devices with pure hematite for PEC water oxidation. Overall, the nanostructured p-NiFe 2 O 4 /n-Fe 2 O 3 device with equal molar 1:1 ratio of NiFe 2 O 4 and Fe 2 O 3 was found to be highly efficient for PEC water oxidation as compared with pure hematite, 1:2 and 1:3 molar ratios of composite. The photocurrent density of 1:1 composite thin film on planar substrate was equal to 1.07 mA/cm 2 at 1.23 V RHE , which was 1.7 times higher current density as compared with pure hematite device (0.63 mA/cm 2 at 1.23 V RHE ). The performance of p-NiFe 2 O 4 /n-Fe 2 O 3 composites in PEC water oxidation was further enhanced by their deposition over 3D-NSP substrate. The highest photocurrent density of 2.1 mA/cm 2 at 1.23 V RHE was obtained for the 1:1 molar ratio p-NiFe 2 O 4 /n-Fe 2 O 3 composite on NSP (NF1-NSP), which was 3.3 times more photocurrent density than pure hematite. The measured applied bias photon-to-current efficiency (ABPE) value of NF1-NSP (0.206%) was found to be 1.87 times higher than that of NF1-P (0.11%) and 4.7 times higher than that of pure hematite deposited on FTO-coated glass (0.044%). The higher PEC water oxidation activity of p-NiFe 2 O 4 /n-Fe 2 O 3 composite thin film as compared with pure hematite is attributed to the Z-path scheme and better separation of electrons and holes. The increased surface area and greater light

Non-equilibrium Modeling of the Fe XVII 3C/3D Line Ratio in an Intense X-Ray Free-Electron Laser Excited Plasma

Science.gov (United States)

Loch, S. D.; Ballance, C. P.; Li, Y.; Fogle, M.; Fontes, C. J.

2015-03-01

Recent measurements using an X-ray Free Electron Laser (XFEL) and an Electron Beam Ion Trap at the Linac Coherent Light Source facility highlighted large discrepancies between the observed and theoretical values for the Fe xvii 3C/3D line intensity ratio. This result raised the question of whether the theoretical oscillator strengths may be significantly in error, due to insufficiencies in the atomic structure calculations. We present time-dependent spectral modeling of this experiment and show that non-equilibrium effects can dramatically reduce the predicted 3C/3D line intensity ratio, compared with that obtained by simply taking the ratio of oscillator strengths. Once these non-equilibrium effects are accounted for, the measured line intensity ratio can be used to determine a revised value for the 3C/3D oscillator strength ratio, giving a range from 3.0 to 3.5. We also provide a framework to narrow this range further, if more precise information about the pulse parameters can be determined. We discuss the implications of the new results for the use of Fe xvii spectral features as astrophysical diagnostics and investigate the importance of time-dependent effects in interpreting XFEL-excited plasmas.

Atlas-Based Automatic Generation of Subject-Specific Finite Element Tongue Meshes.

Science.gov (United States)

Bijar, Ahmad; Rohan, Pierre-Yves; Perrier, Pascal; Payan, Yohan

2016-01-01

Generation of subject-specific 3D finite element (FE) models requires the processing of numerous medical images in order to precisely extract geometrical information about subject-specific anatomy. This processing remains extremely challenging. To overcome this difficulty, we present an automatic atlas-based method that generates subject-specific FE meshes via a 3D registration guided by Magnetic Resonance images. The method extracts a 3D transformation by registering the atlas' volume image to the subject's one, and establishes a one-to-one correspondence between the two volumes. The 3D transformation field deforms the atlas' mesh to generate the subject-specific FE mesh. To preserve the quality of the subject-specific mesh, a diffeomorphic non-rigid registration based on B-spline free-form deformations is used, which guarantees a non-folding and one-to-one transformation. Two evaluations of the method are provided. First, a publicly available CT-database is used to assess the capability to accurately capture the complexity of each subject-specific Lung's geometry. Second, FE tongue meshes are generated for two healthy volunteers and two patients suffering from tongue cancer using MR images. It is shown that the method generates an appropriate representation of the subject-specific geometry while preserving the quality of the FE meshes for subsequent FE analysis. To demonstrate the importance of our method in a clinical context, a subject-specific mesh is used to simulate tongue's biomechanical response to the activation of an important tongue muscle, before and after cancer surgery.

3D CNT macrostructure synthesis catalyzed by MgFe2O4 nanoparticles-A study of surface area and spinel inversion influence

Science.gov (United States)

Zampiva, Rúbia Young Sun; Kaufmann Junior, Claudir Gabriel; Pinto, Juliano Schorne; Panta, Priscila Chaves; Alves, Annelise Kopp; Bergmann, Carlos Pérez

2017-11-01

The MgFe2O4 spinel exhibits remarkable magnetic properties that open up numerous applications in biomedicine, the environment and catalysis. MgFe2O4 nanoparticles are excellent catalyst for carbon nanotube (CNT) production. In this work, we proposed to use MgFe2O4 nanopowder as a catalyst in the production of 3D macroscopic structures based on CNTs. The creation of these nanoengineered 3D architectures remains one of the most important challenges in nanotechnology. These systems have high potential as supercapacitors, catalytic electrodes, artificial muscles and in environmental applications. 3D macrostructures are formed due to an elevated density of CNTs. The quantity and quality of the CNTs are directly related to the catalyst properties. A heat treatment study was performed to produce the most effective catalyst. Factors such as superficial area, spinel inversion, crystallite size, degree of agglomeration and its correlation with van der Waals forces were examined. As result, the ideal catalyst properties for CNT production were determined and high-density 3D CNT macrostructures were produced successfully.

Automatic Segmentation of the Eye in 3D Magnetic Resonance Imaging: A Novel Statistical Shape Model for Treatment Planning of Retinoblastoma.

Science.gov (United States)

Ciller, Carlos; De Zanet, Sandro I; Rüegsegger, Michael B; Pica, Alessia; Sznitman, Raphael; Thiran, Jean-Philippe; Maeder, Philippe; Munier, Francis L; Kowal, Jens H; Cuadra, Meritxell Bach

2015-07-15

Proper delineation of ocular anatomy in 3-dimensional (3D) imaging is a big challenge, particularly when developing treatment plans for ocular diseases. Magnetic resonance imaging (MRI) is presently used in clinical practice for diagnosis confirmation and treatment planning for treatment of retinoblastoma in infants, where it serves as a source of information, complementary to the fundus or ultrasonographic imaging. Here we present a framework to fully automatically segment the eye anatomy for MRI based on 3D active shape models (ASM), and we validate the results and present a proof of concept to automatically segment pathological eyes. Manual and automatic segmentation were performed in 24 images of healthy children's eyes (3.29 ± 2.15 years of age). Imaging was performed using a 3-T MRI scanner. The ASM consists of the lens, the vitreous humor, the sclera, and the cornea. The model was fitted by first automatically detecting the position of the eye center, the lens, and the optic nerve, and then aligning the model and fitting it to the patient. We validated our segmentation method by using a leave-one-out cross-validation. The segmentation results were evaluated by measuring the overlap, using the Dice similarity coefficient (DSC) and the mean distance error. We obtained a DSC of 94.90 ± 2.12% for the sclera and the cornea, 94.72 ± 1.89% for the vitreous humor, and 85.16 ± 4.91% for the lens. The mean distance error was 0.26 ± 0.09 mm. The entire process took 14 seconds on average per eye. We provide a reliable and accurate tool that enables clinicians to automatically segment the sclera, the cornea, the vitreous humor, and the lens, using MRI. We additionally present a proof of concept for fully automatically segmenting eye pathology. This tool reduces the time needed for eye shape delineation and thus can help clinicians when planning eye treatment and confirming the extent of the tumor. Copyright © 2015 Elsevier Inc. All rights reserved.

A New Method for 3D Finite Element Modeling of Human Mandible Based on CT Data

Institute of Scientific and Technical Information of China (English)

于力牛; 叶铭; 王成焘

2004-01-01

This study presents a reliable method for the semi-automatic generation of an FE model, which determines both geometrical data and bone properties from patient CT scans.3D FE analysis is one of the best approaches to predict the stress and strain distribution in complex bone structures, but its accuracy strongly depends on the precision of input information. In geometric reconstruction, various methods of image processing, geometric modeling and finite element analysis are combined and extended. Emphasis is given to the assignment of the material properties based on the density values computed from CT data. Through this technique, the model with high geometric and material similarities were generated in an easy way. Consequently, the patient-specific FE model from mandible CT data is realized also.

alpha-Fe2O3 versus beta-Fe2O3: Controlling the Phase of the Transformation Product of epsilon-Fe2O3 in the Fe2O3/SiO2 System

Czech Academy of Sciences Publication Activity Database

Brázda, Petr; Kohout, J.; Bezdička, Petr; Kmjec, T.

2014-01-01

Roč. 14, č. 3 (2014), s. 1039-1046 ISSN 1528-7483 R&D Projects: GA ČR GAP204/10/0035 Institutional support: RVO:61388980 Keywords : CHEMICAL-VAPOR-DEPOSITION * OXIDE THIN-FILMS * X-RAY * GAMMA-FE2O3 NANOPARTICLES * THERMAL-DECOMPOSITION Subject RIV: CA - Inorganic Chemistry Impact factor: 4.891, year: 2014

Nearly automatic motion capture system for tracking octopus arm movements in 3D space.

Science.gov (United States)

Zelman, Ido; Galun, Meirav; Akselrod-Ballin, Ayelet; Yekutieli, Yoram; Hochner, Binyamin; Flash, Tamar

2009-08-30

Tracking animal movements in 3D space is an essential part of many biomechanical studies. The most popular technique for human motion capture uses markers placed on the skin which are tracked by a dedicated system. However, this technique may be inadequate for tracking animal movements, especially when it is impossible to attach markers to the animal's body either because of its size or shape or because of the environment in which the animal performs its movements. Attaching markers to an animal's body may also alter its behavior. Here we present a nearly automatic markerless motion capture system that overcomes these problems and successfully tracks octopus arm movements in 3D space. The system is based on three successive tracking and processing stages. The first stage uses a recently presented segmentation algorithm to detect the movement in a pair of video sequences recorded by two calibrated cameras. In the second stage, the results of the first stage are processed to produce 2D skeletal representations of the moving arm. Finally, the 2D skeletons are used to reconstruct the octopus arm movement as a sequence of 3D curves varying in time. Motion tracking, segmentation and reconstruction are especially difficult problems in the case of octopus arm movements because of the deformable, non-rigid structure of the octopus arm and the underwater environment in which it moves. Our successful results suggest that the motion-tracking system presented here may be used for tracking other elongated objects.

Growth and Structural, Magnetic, and Magnetooptical Properties of ZnO Films Doped with a Fe57 3 d Impurity

Science.gov (United States)

Mezdrogina, M. M.; Aglikov, A. S.; Semenov, V. G.; Kozhanova, Yu. V.; Nefedov, S. G.; Shelukhin, L. A.; Pavlov, V. V.

2018-03-01

ZnO films obtained by high-frequency magnetron sputtering and doped with a Fe57 metallic 3 d impurity by the diffusion method are studied. The type of local environment of Fe57 impurity atoms on varying the deposition parameters of ZnO films is determined by Mössbauer spectroscopy. It is established that the ground state of Fe57 impurity atoms corresponds to metallic iron in the magnetically ordered state and there is a small fraction of Fe57 atoms with a local environment corresponding to the complex oxide Fe3O4, having the magnetically ordered state; there is also a fraction of iron atoms in the paramagnetic state. The magnetic and magnetooptical parameters of the films were measured using magnetooptic Kerr effect. The spectral dependences of the polar magnetooptic Kerr effect in ZnO(Fe57) films are measured in a photon energy range of 1.5-4.5 eV and simulated by the effective-medium method. It is established that ZnO(Fe57) possess an easy-plane magnetic anisotropy with a magnetization lying in the film plane.

Investigation of orientation gradients around a hard Laves particle in a warm-rolled Fe3Al-based alloy using a 3D EBSD-FIB technique

International Nuclear Information System (INIS)

Konrad, J.; Zaefferer, S.; Raabe, D.

2006-01-01

We present a study of the microstructure around a hard Laves particle in a warm-rolled intermetallic Fe 3 Al-based alloy. The experiments are conducted using a system for three-dimensional orientation microscopy (3D electron backscattering diffraction, EBSD). The approach is realized by a combination of a focused ion beam (FIB) unit for serial sectioning with high-resolution field emission scanning electron microscopy with EBSD. We observe the formation of steep 3D orientation gradients in the Fe 3 Al matrix around the rigid precipitate which entail in part particle-stimulated nucleation events in the immediate vicinity of the particle. The orientation gradients assume a characteristic pattern around the particle in the transverse plane while revealing an elongated tubular morphology in the rolling direction. However, they do not reveal a characteristic common rotation axis. Recovered areas in the matrix appear both in the transverse and rolling directions around the particle. The work demonstrates that the new 3D EBSD-FIB technique provides a new level of microstructure information that cannot be achieved by conventional 2D-EBSD analysis

The solubility and site preference of Fe{sup 3+} in Li{sub 7−3x}Fe{sub x}La{sub 3}Zr{sub 2}O{sub 12} garnets

Energy Technology Data Exchange (ETDEWEB)

Rettenwander, D., E-mail: daniel.rettenwander@sbg.ac.at [Department of Materials Research and Physics, University of Salzburg, 5020 Salzburg (Austria); Geiger, C.A. [Department of Materials Research and Physics, University of Salzburg, 5020 Salzburg (Austria); Tribus, M.; Tropper, P. [Institute of Mineralogy and Petrography, Faculty of Geo- and Atmospheric Sciences, University of Innsbruck, Innrain 52, 6020 Innsbruck (Austria); Wagner, R.; Tippelt, G.; Lottermoser, W.; Amthauer, G. [Department of Materials Research and Physics, University of Salzburg, 5020 Salzburg (Austria)

2015-10-15

A series of Fe{sup 3+}-bearing Li{sub 7}La{sub 3}Zr{sub 2}O{sub 12} (LLZO) garnets was synthesized using solid-state synthesis methods. The synthetic products were characterized compositionally using electron microprobe analysis and inductively coupled plasma optical emission spectroscopy (ICP-OES) and structurally using X-ray powder diffraction and {sup 57}Fe Mössbauer spectroscopy. A maximum of about 0.25 Fe{sup 3+} pfu could be incorporated in Li{sub 7−3x}Fe{sub x}La{sub 3}Zr{sub 2}O{sub 12} garnet solid solutions. At Fe{sup 3+} concentrations lower than about 0.16 pfu, both tetragonal and cubic garnets were obtained in the synthesis experiments. X-ray powder diffraction analysis showed only a garnet phase for syntheses with starting materials having intended Fe{sup 3+} contents lower than 0.52 Fe{sup 3+} pfu. Back-scattered electron images made with an electron microprobe also showed no phase other than garnet for these compositions. The lattice parameter, a{sub 0}, for all solid-solution garnets is similar with a value of a{sub 0}≈12.98 Å regardless of the amount of Fe{sup 3+}. {sup 57}Fe Mössbauer spectroscopic measurements indicate the presence of poorly- or nano-crystalline FeLaO{sub 3} in syntheses with Fe{sup 3+} contents greater than 0.16 Fe{sup 3+} pfu. The composition of different phase pure Li{sub 7−3x}Fe{sub x}La{sub 3}Zr{sub 2}O{sub 12} garnets, as determined by electron microprobe (Fe, La, Zr) and ICP-OES (Li) measurements, give Li{sub 6.89}Fe{sub 0.03}La{sub 3.05}Zr{sub 2.01}O{sub 12}, Li{sub 6.66}Fe{sub 0.06}La{sub 3.06}Zr{sub 2.01}O{sub 12}, Li{sub 6.54}Fe{sub 0.12}La{sub 3.01}Zr{sub 1.98}O{sub 12}, and Li{sub 6.19}Fe{sub 0.19}La{sub 3.02}Zr{sub 2.04}O{sub 12}. The {sup 57}Fe Mössbauer spectrum of cubic Li{sub 6.54}Fe{sub 0.12}La{sub 3.01}Zr{sub 1.98}O{sub 12} garnet indicates that most Fe{sup 3+} occurs at the special crystallographic 24d position, which is the standard tetrahedrally coordinated site in garnet. Fe{sup 3+} in smaller

Production of sup 5 sup 5 Co via the sup 5 sup 4 Fe(d, n)-process and excitation functions of sup 5 sup 4 Fe(d, t) sup 5 sup 3 Fe and sup 5 sup 4 Fe(d, alpha) sup 5 sup 2 sup m Mn reactions from threshold up to 13.8 MeV

CERN Document Server

Zaman, M R; Qaim, S M

2003-01-01

For production of the medically interesting beta; sup + -emitter sup 5 sup 5 Co (T sup 1 sup / sup 2 = 17.6 h) via the sup 5 sup 4 Fe(d, n)-reaction, 91.6% enriched sup 5 sup 4 Fe sub 2 O sub 3 , mixed with Al powder, was pressed to a pellet which could be irradiated with 14 MeV deuterons at 4 mu A in a water-cooled target system. A separation method was developed which led to > 99.9% pure sup 5 sup 5 Co and allowed a recovery of the enriched target material. For a target thickness of E sub d = 12.6 -> 5 MeV, the experimental thick target yield of sup 5 sup 5 Co after chemical separation amounted to about 13 MBq/mu A.h, which is about 60% of the theoretical value. In a 3 h irradiation at 4 mu A, the batch yield of sup 5 sup 5 Co achieved was 160 MBq (4.3 mCi). An 8 h irradiation could lead to a batch yield of about 400 MBq. The sup 5 sup 4 Fe(d, n) reaction leads to the highest purity sup 5 sup 5 Co but it is essential that the isotopic enrichment of the target is not less than 90%. In addition to the product...

Large positive spin polarization and giant inverse tunneling magnetoresistance in Fe/PbTiO3/Fe multiferroic tunnel junction

International Nuclear Information System (INIS)

Dai, Jian-Qing; Zhang, Hu; Song, Yu-Min

2014-01-01

We perform first-principles electronic structure and spin-dependent transport calculations of a multiferroic tunnel junction (MFTJ) with an epitaxial Fe/PbTiO 3 /Fe heterostructure. We predict a large positive spin-polarization (SP) and an intriguing giant inverse tunneling magnetoresistance (TMR) ratio in this tunnel junction. We demonstrate that the tunneling properties are determined by ferroelectric (FE) polarization screening and electronic reconstruction at the interface with lower electrostatic potential. The intricate complex band structure of PbTiO 3 , in particular the lowest decay rates concerning Pb 6p z and Ti 3d z2 states near the Γ ¯ point, gives rise to the large positive SP of the tunneling current in the parallel magnetic configuration. However, the giant inverse TMR ratio is attributed to the minority-spin electrons of the interfacial Ti 3d xz +3d yz orbitals which have considerably weight in the extended area around the Γ ¯ point at the Fermi energy and causes remarkable contributions to the conductance in the antiparallel magnetic configuration. - Highlights: • We study spin-dependent tunneling in Fe/PbTiO 3 /Fe multiferroic tunnel junction. • We find a large positive spin polarization in the parallel magnetic configuration. • An intriguing giant inverse TMR ratio (about −2000%) is predicted. • Complex band structure of PbTiO 3 causes the large positive spin polarization. • Negative TMR is due to minority-spin electrons of interfacial Ti d xz +d yz orbitals

Luminescence and magnetic properties of novel nanoparticle-sheathed 3D Micro-Architectures of Fe0.5R0.5(MoO4)1.5:Ln3+ (R = Gd3+, La3+), (Ln = Eu, Tb, Dy) for bifunctional application

Science.gov (United States)

Krishnan, Rajagopalan; Thirumalai, Jagannathan; Kathiravan, Arunkumar

2015-01-01

For the first time, we report the successful synthesis of novel nanoparticle-sheathed bipyramid-like and almond-like Fe0.5R0.5(MoO4)1.5:Ln3+ (R = Gd3+, La3+), (Ln = Eu, Tb, Dy) 3D hierarchical microstructures through a simple disodium ethylenediaminetetraacetic acid (Na2EDTA) facilitated hydrothermal method. Interestingly, time-dependent experiments confirm that the assembly-disassembly process is responsible for the formation of self-aggregated 3D architectures via Ostwald ripening phenomena. The resultant products are characterized by x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), photoluminescence (PL), and magnetic measurements. The growth and formation mechanisms of the self-assembled 3D micro structures are discussed in detail. To confirm the presence of all the elements in the microstructure, the energy loss induced by the K, L shell electron ionization is observed in order to map the Fe, Gd, Mo, O, and Eu components. The photo luminescence properties of Fe0.5R0.5(MoO4)1.5 doped with Eu3+, Tb3+, Dy3+ are investigated. The room temperature and low temperature magnetic properties suggest that the interaction between the local-fields introduced by the magnetic Fe3+ ions and the R3+ (La, Gd) ions in the dodecahedral sites determine the magnetism in Fe0.5R0.5(MoO4)1.5:Eu3+. This work provides a new approach to synthesizing the novel Fe0.5R0.5(MoO4)1.5:Ln3+ for bi-functional magnetic and luminescence applications.

Automatic segmentation and 3D reconstruction of intravascular ultrasound images for a fast preliminar evaluation of vessel pathologies.

Science.gov (United States)

Sanz-Requena, Roberto; Moratal, David; García-Sánchez, Diego Ramón; Bodí, Vicente; Rieta, José Joaquín; Sanchis, Juan Manuel

2007-03-01

Intravascular ultrasound (IVUS) imaging is used along with X-ray coronary angiography to detect vessel pathologies. Manual analysis of IVUS images is slow and time-consuming and it is not feasible for clinical purposes. A semi-automated method is proposed to generate 3D reconstructions from IVUS video sequences, so that a fast diagnose can be easily done, quantifying plaque length and severity as well as plaque volume of the vessels under study. The methodology described in this work has four steps: a pre-processing of IVUS images, a segmentation of media-adventitia contour, a detection of intima and plaque and a 3D reconstruction of the vessel. Preprocessing is intended to remove noise from the images without blurring the edges. Segmentation of media-adventitia contour is achieved using active contours (snakes). In particular, we use the gradient vector flow (GVF) as external force for the snakes. The detection of lumen border is obtained taking into account gray-level information of the inner part of the previously detected contours. A knowledge-based approach is used to determine which level of gray corresponds statistically to the different regions of interest: intima, plaque and lumen. The catheter region is automatically discarded. An estimate of plaque type is also given. Finally, 3D reconstruction of all detected regions is made. The suitability of this methodology has been verified for the analysis and visualization of plaque length, stenosis severity, automatic detection of the most problematic regions, calculus of plaque volumes and a preliminary estimation of plaque type obtaining for automatic measures of lumen and vessel area an average error smaller than 1mm(2) (equivalent aproximately to 10% of the average measure), for calculus of plaque and lumen volume errors smaller than 0.5mm(3) (equivalent approximately to 20% of the average measure) and for plaque type estimates a mismatch of less than 8% in the analysed frames.

A Dilute-Limit Heat of Solution of 3d Transition Metals in Iron Studied with 57Fe Moessbauer Spectroscopy

International Nuclear Information System (INIS)

Chojcan, Jan

2004-01-01

The room-temperature 57 Fe Moessbauer spectra for binary iron-based solid solutions Fe 1-x D x with D=V, Cr, Mn and Co, were analysed in terms of binding energy E b between two D atoms in the Fe-D system. The extrapolated values of E b for x=0 were used for computation of the dilute-limit heat of solution of D metals in iron. The results were compared with those derived from calorimetric data concerning the heat of formation of the systems mentioned as well as with those resulting from the Miedema's model of alloys. The comparison shows that our Moessbauer spectroscopy findings are in a qualitative agreement with the available calorimetric data and they are at variance with corresponding Miedema's values for Fe-Mn and Fe-Co systems.

The bonding character and magnetic properties of Fe{sub 3}Al: Comparison between disordered and ordered alloy

Energy Technology Data Exchange (ETDEWEB)

Fan Runhua [MOE Key Laboratory for Liquid Structure and Heredity of Materials, Shandong University, Jinan 250061 (China)]. E-mail: fan@sdu.edu.cn; Qi Liang [MOE Key Laboratory for Liquid Structure and Heredity of Materials, Shandong University, Jinan 250061 (China); Sun Kangning [MOE Key Laboratory for Liquid Structure and Heredity of Materials, Shandong University, Jinan 250061 (China); Min Guanghui [MOE Key Laboratory for Liquid Structure and Heredity of Materials, Shandong University, Jinan 250061 (China); Gong Hongyu [MOE Key Laboratory for Liquid Structure and Heredity of Materials, Shandong University, Jinan 250061 (China)

2006-12-25

Fe{sub 3}Al with D0{sub 3}-ordered structure is one of the few structural intermetallics that can be disordered using non-equilibrium processing techniques. The bonding and magnetic character of the stoichiometric Fe{sub 3}Al, with D0{sub 3}-ordered or disordered structure, have been studied using the empirical electron theory of solid and molecular (EET). It was found that the magnetic property is basically dictated by the chemical bonding. There is a change of the character of the interatomic bonds from 3d(Fe)-3p(Al) for the D0{sub 3}-ordered Fe{sub 3}Al to 4sp(Fe)-3p(Al) for the disordered Fe{sub 3}Al. For the latter, while the Fe 3d electrons participating in bonding is reduced, the mean magnetic moment is increased.

AUTOMATIC MESH GENERATION OF 3-D GEOMETRIC MODELS

Institute of Scientific and Technical Information of China (English)

刘剑飞

2003-01-01

In this paper the presentation of the ball-packing method is reviewed,and a scheme to generate mesh for complex 3-D geometric models is given,which consists of 4 steps:(1)create nodes in 3-D models by ball-packing method,(2)connect nodes to generate mesh by 3-D Delaunay triangulation,(3)retrieve the boundary of the model after Delaunay triangulation,(4)improve the mesh.

3-D laser confocal microscopy study of the oxidation of NdFeB magnets in atmospheric conditions

International Nuclear Information System (INIS)

Meakin, J.P.; Speight, J.D.; Sheridan, R.S.; Bradshaw, A.; Harris, I.R.; Williams, A.J.; Walton, A.

2016-01-01

Highlights: • Room temperature atmospheric oxidation behaviour of sintered NdFeB. • 3D laser confocal microscopy measurement of oxide phase growth. • Significant height increase of oxide phase only observed at triple points. • Raman spectroscopy identified oxide phase to be Nd 2 O 3 . • Diffusion coefficient determined to be 4 × 10 −13 cm 2 /s. - Abstract: Neodymium iron boron (NdFeB) magnets are used in a number of important applications, such as generators in gearless wind turbines, motors in electric vehicles and electronic goods (e.g.— computer hard disk drives, HDD). Hydrogen can be used as a processing gas to separate and recycle scrap sintered Nd-Fe-B magnets from end-of-life products to form a powder suitable for recycling. However, the magnets are likely to have been exposed to atmospheric conditions prior to processing, and any oxidation could lead to activation problems for the hydrogen decrepitation reaction. Many previous studies on the oxidation of NdFeB magnets have been performed at elevated temperatures; however, few studies have been formed under atmospheric conditions. In this paper a combination of 3-D laser confocal microscopy and Raman spectroscopy have been used to assess the composition, morphology and rate of oxidation/corrosion on scrap sintered NdFeB magnets. Confocal microscopy has been employed to measure the growth of surface reaction products at room temperature, immediately after exposure to air. The results showed that there was a significant height increase at the triple junctions of the Nd-rich grain boundaries. Using Raman spectroscopy, the product was shown to consist of Nd 2 O 3 and formed only on the Nd-rich triple junctions. The diffusion coefficient of the triple junction reaction product growth at 20 °C was determined to be approximately 4 × 10 −13 cm 2 /sec. This value is several orders of magnitude larger than values derived from the diffusion controlled oxide growth observations at elevated

3-D laser confocal microscopy study of the oxidation of NdFeB magnets in atmospheric conditions

Energy Technology Data Exchange (ETDEWEB)

Meakin, J.P., E-mail: jxm764@bham.ac.uk; Speight, J.D.; Sheridan, R.S.; Bradshaw, A.; Harris, I.R.; Williams, A.J.; Walton, A.

2016-08-15

Highlights: • Room temperature atmospheric oxidation behaviour of sintered NdFeB. • 3D laser confocal microscopy measurement of oxide phase growth. • Significant height increase of oxide phase only observed at triple points. • Raman spectroscopy identified oxide phase to be Nd{sub 2}O{sub 3}. • Diffusion coefficient determined to be 4 × 10{sup −13} cm{sup 2}/s. - Abstract: Neodymium iron boron (NdFeB) magnets are used in a number of important applications, such as generators in gearless wind turbines, motors in electric vehicles and electronic goods (e.g.— computer hard disk drives, HDD). Hydrogen can be used as a processing gas to separate and recycle scrap sintered Nd-Fe-B magnets from end-of-life products to form a powder suitable for recycling. However, the magnets are likely to have been exposed to atmospheric conditions prior to processing, and any oxidation could lead to activation problems for the hydrogen decrepitation reaction. Many previous studies on the oxidation of NdFeB magnets have been performed at elevated temperatures; however, few studies have been formed under atmospheric conditions. In this paper a combination of 3-D laser confocal microscopy and Raman spectroscopy have been used to assess the composition, morphology and rate of oxidation/corrosion on scrap sintered NdFeB magnets. Confocal microscopy has been employed to measure the growth of surface reaction products at room temperature, immediately after exposure to air. The results showed that there was a significant height increase at the triple junctions of the Nd-rich grain boundaries. Using Raman spectroscopy, the product was shown to consist of Nd{sub 2}O{sub 3} and formed only on the Nd-rich triple junctions. The diffusion coefficient of the triple junction reaction product growth at 20 °C was determined to be approximately 4 × 10{sup −13} cm{sup 2}/sec. This value is several orders of magnitude larger than values derived from the diffusion controlled oxide growth

Study on adsorption of 99Tc on Fe, Fe2O3 and Fe3O4

International Nuclear Information System (INIS)

Liu Dejun; Fan Xianhua; Zhang Yingjie; Yao Jun; Zhou Duo; Wang Yong

2004-01-01

The absorption behavior of 99 Tc on Fe, Fe 2 O 3 and Fe 3 O 4 powders from aqueous 99 TcO 4 - solutions is studied by batch method in atmospheric conditions. After the adsorption reaches equilibrium, the valence state of 99 Tc in the aqueous solution is examined by extraction with tetraphenylarsonium chloride. The experimental results show that the adsorption ratio of 99 Tc on iron powders decreases with the increase of pH (in the range of 5-8) and of CO 3 2- concentration (in the range of 1 x 10 -8 -1 x 10 -2 mol/L). In opposite, the two factors have no significant influence on the absorption of 99 Tc on both Fe 2 O 3 and Fe 3 O 4 powders. The adsorption isotherms of 99 TcO 4 - on Fe, Fe 2 O 3 and Fe 3 O 4 powders can be well described by the Freundlich's equation. The major valence state of 99 Tc is deduced to be Tc(IV) when iron powders is used as the absorbent. In the case of Fe 2 O 3 or Fe 3 O 4 as an absorbent, the 99 Tc remains as the TcO 4 - form

Numerical fatigue 3D-FE modeling of indirect composite-restored posterior teeth.

Science.gov (United States)

Ausiello, Pietro; Franciosa, Pasquale; Martorelli, Massimo; Watts, David C

2011-05-01

In restored teeth, stresses at the tooth-restoration interface during masticatory processes may fracture the teeth or the restoration and cracks may grow and propagate. The aim was to apply numerical methodologies to simulate the behavior of a restored tooth and to evaluate fatigue lifetimes before crack failure. Using a CAD-FEM procedure and fatigue mechanic laws, the fatigue damage of a restored molar was numerically estimated. Tessellated surfaces of enamel and dentin were extracted by applying segmentation and classification algorithms, to sets of 2D image data. A user-friendly GUI, which enables selection and visualization of 3D tessellated surfaces, was developed in a MatLab(®) environment. The tooth-boundary surfaces of enamel and dentin were then created by sweeping operations through cross-sections. A class II MOD cavity preparation was then added into the 3D model and tetrahedral mesh elements were generated. Fatigue simulation was performed by combining a preliminary static FEA simulation with classical fatigue mechanical laws. Regions with the shortest fatigue-life were located around the fillets of the class II MOD cavity, where the static stress was highest. The described method can be successfully adopted to generate detailed 3D-FE models of molar teeth, with different cavities and restorative materials. This method could be quickly implemented for other dental or biomechanical applications. Copyright © 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Chemistry of CCl 4 on Fe 3O 4(1 1 1)-(2 × 2) surfaces in the presence of adsorbed D 2O studied by temperature programmed desorption

Science.gov (United States)

Adib, K.; Totir, G. G.; Fitts, J. P.; Rim, K. T.; Mueller, T.; Flynn, G. W.; Joyce, S. A.; Osgood, R. M.

2003-07-01

Temperature programmed desorption (TPD) was used to study surface reactions of Fe 3O 4(1 1 1)-(2 × 2) sequentially exposed, at ˜100 K, to vapor-phase D 2O and CCl 4. Previous TPD and XPS results have indicated that in the absence of D 2O, CCl 4 dissociatively adsorbs on Fe 3O 4(1 1 1) producing chemisorbed Cl and CCl 2. Subsequent heating of the surface results in abstraction of lattice iron and oxygen atoms and causes them to desorb as FeCl 2 and OCCl 2, respectively. This study shows that when this Fe 3O 4 surface is exposed only to D 2O, TPD measures a rich surface chemistry with multiple desorption events extending as high as ˜800 K, indicating dissociative adsorption of D 2O on the Fe 3O 4(1 1 1) surface. After sequential exposure to D 2O and then CCl 4, the production of FeCl 2 and OCCl 2 from adsorbed CCl 4 is suppressed, indicating that D 2O fragments block the surface reactive sites.

Automatic segmentation of low-visibility moving objects through energy analyis of the local 3D spectrum

Science.gov (United States)

Nestares, Oscar; Miravet, Carlos; Santamaria, Javier; Fonolla Navarro, Rafael

1999-05-01

Automatic object segmentation in highly noisy image sequences, composed by a translating object over a background having a different motion, is achieved through joint motion-texture analysis. Local motion and/or texture is characterized by the energy of the local spatio-temporal spectrum, as different textures undergoing different translational motions display distinctive features in their 3D (x,y,t) spectra. Measurements of local spectrum energy are obtained using a bank of directional 3rd order Gaussian derivative filters in a multiresolution pyramid in space- time (10 directions, 3 resolution levels). These 30 energy measurements form a feature vector describing texture-motion for every pixel in the sequence. To improve discrimination capability and reduce computational cost, we automatically select those 4 features (channels) that best discriminate object from background, under the assumptions that the object is smaller than the background and has a different velocity or texture. In this way we reject features irrelevant or dominated by noise, that could yield wrong segmentation results. This method has been successfully applied to sequences with extremely low visibility and for objects that are even invisible for the eye in absence of motion.

Controlled Confinement of Half-metallic 2D Electron Gas in BaTiO3/Ba2FeReO6/BaTiO3 Heterostructures: A First-principles Study

Science.gov (United States)

Saha-Dasgupta, Tanusri; Baidya, Santu; Waghmare, Umesh; Paramekanti, Arun

Using density functional theory calculations, we establish that the half-metallicity of bulk Ba2FeReO6 survives down i to 1 nm thickness in BaTiO3/Ba2FeReO6/BaTiO3 heterostructures grown along the (001) and (111) directions. The confinement of the two-dimensional (2D) electron gas in this quantum well structure arises from the suppressed hybridization between Re/Fe d states and unoccupied Ti d states, and it is further strengthened by polar fields for the (111) direction. This mechanism, distinct from the polar catastrophe, leads to an order of magnitude stronger confinement of the 2D electron gas than that at the LaAlO3/SrTiO3 interface. We further show low-energy bands of (111) heterostructure display nontrivial topological character. Our work opens up the possibility of realizing ultra-thin spintronic devices. Journal Ref: Phys. Rev. B 92, 161106(R) (2015) S.B. and T.S.D thank Department of Science and Technology, India for the support through Thematic Unit of Excellence. AP was supported by NSERC (Canada).

Fabricate BC/Fe3O4@PPy 3D nanofiber film as flexible electrode for supercapacitor application

Science.gov (United States)

Lv, Xvdan; Li, Guohui; Pang, Zengyuan; Li, Dawei; Lei, Luo; Lv, Pengfei; Mushtaq, Muhammad; Wei, Qufu

2018-05-01

For flexible film supercapacitor, high areal capacitance is a main evaluating indicator. In this paper, bacterial cellulose (BC) with special three-dimensional structure was used as the natural flexible base material. Fe3O4 nanoparticles with average diameter of 20 nm were synthesized on the surface of BC fibers. The conductive path polypyrrole (PPy) was introduced as shell of BC/Fe3O4 fibers to further improve the pseudo capacitance in 1 mol/L H2SO4 solution. Besides, the BC/Fe3O4@PPy was used for supercapacitor application in acid electrolyte, and delivered higher areal capacitance compared to other Fe3O4 composites in previous reports. The obtained BC/Fe3O4@PPy film showed excellent mechanical strength (tensile strength reached 11 MPa), high areal specific capacitance (5.4 F cm-2 at active mass of 8.4 mg cm-2), and long cycle life (1.95 F cm-2 over 3500 cycles).

Automatic Segmentation of the Eye in 3D Magnetic Resonance Imaging: A Novel Statistical Shape Model for Treatment Planning of Retinoblastoma

Energy Technology Data Exchange (ETDEWEB)

Ciller, Carlos, E-mail: carlos.cillerruiz@unil.ch [Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne (Switzerland); Ophthalmic Technology Group, ARTORG Center of the University of Bern, Bern (Switzerland); Centre d’Imagerie BioMédicale, University of Lausanne, Lausanne (Switzerland); De Zanet, Sandro I.; Rüegsegger, Michael B. [Ophthalmic Technology Group, ARTORG Center of the University of Bern, Bern (Switzerland); Department of Ophthalmology, Inselspital, Bern University Hospital, Bern (Switzerland); Pica, Alessia [Department of Radiation Oncology, Inselspital, Bern University Hospital, Bern (Switzerland); Sznitman, Raphael [Ophthalmic Technology Group, ARTORG Center of the University of Bern, Bern (Switzerland); Department of Ophthalmology, Inselspital, Bern University Hospital, Bern (Switzerland); Thiran, Jean-Philippe [Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne (Switzerland); Signal Processing Laboratory, École Polytechnique Fédérale de Lausanne, Lausanne (Switzerland); Maeder, Philippe [Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne (Switzerland); Munier, Francis L. [Unit of Pediatric Ocular Oncology, Jules Gonin Eye Hospital, Lausanne (Switzerland); Kowal, Jens H. [Ophthalmic Technology Group, ARTORG Center of the University of Bern, Bern (Switzerland); Department of Ophthalmology, Inselspital, Bern University Hospital, Bern (Switzerland); and others

2015-07-15

Purpose: Proper delineation of ocular anatomy in 3-dimensional (3D) imaging is a big challenge, particularly when developing treatment plans for ocular diseases. Magnetic resonance imaging (MRI) is presently used in clinical practice for diagnosis confirmation and treatment planning for treatment of retinoblastoma in infants, where it serves as a source of information, complementary to the fundus or ultrasonographic imaging. Here we present a framework to fully automatically segment the eye anatomy for MRI based on 3D active shape models (ASM), and we validate the results and present a proof of concept to automatically segment pathological eyes. Methods and Materials: Manual and automatic segmentation were performed in 24 images of healthy children's eyes (3.29 ± 2.15 years of age). Imaging was performed using a 3-T MRI scanner. The ASM consists of the lens, the vitreous humor, the sclera, and the cornea. The model was fitted by first automatically detecting the position of the eye center, the lens, and the optic nerve, and then aligning the model and fitting it to the patient. We validated our segmentation method by using a leave-one-out cross-validation. The segmentation results were evaluated by measuring the overlap, using the Dice similarity coefficient (DSC) and the mean distance error. Results: We obtained a DSC of 94.90 ± 2.12% for the sclera and the cornea, 94.72 ± 1.89% for the vitreous humor, and 85.16 ± 4.91% for the lens. The mean distance error was 0.26 ± 0.09 mm. The entire process took 14 seconds on average per eye. Conclusion: We provide a reliable and accurate tool that enables clinicians to automatically segment the sclera, the cornea, the vitreous humor, and the lens, using MRI. We additionally present a proof of concept for fully automatically segmenting eye pathology. This tool reduces the time needed for eye shape delineation and thus can help clinicians when planning eye treatment and confirming the extent of the tumor.

Automatic Segmentation of the Eye in 3D Magnetic Resonance Imaging: A Novel Statistical Shape Model for Treatment Planning of Retinoblastoma

International Nuclear Information System (INIS)

Ciller, Carlos; De Zanet, Sandro I.; Rüegsegger, Michael B.; Pica, Alessia; Sznitman, Raphael; Thiran, Jean-Philippe; Maeder, Philippe; Munier, Francis L.; Kowal, Jens H.

2015-01-01

Purpose: Proper delineation of ocular anatomy in 3-dimensional (3D) imaging is a big challenge, particularly when developing treatment plans for ocular diseases. Magnetic resonance imaging (MRI) is presently used in clinical practice for diagnosis confirmation and treatment planning for treatment of retinoblastoma in infants, where it serves as a source of information, complementary to the fundus or ultrasonographic imaging. Here we present a framework to fully automatically segment the eye anatomy for MRI based on 3D active shape models (ASM), and we validate the results and present a proof of concept to automatically segment pathological eyes. Methods and Materials: Manual and automatic segmentation were performed in 24 images of healthy children's eyes (3.29 ± 2.15 years of age). Imaging was performed using a 3-T MRI scanner. The ASM consists of the lens, the vitreous humor, the sclera, and the cornea. The model was fitted by first automatically detecting the position of the eye center, the lens, and the optic nerve, and then aligning the model and fitting it to the patient. We validated our segmentation method by using a leave-one-out cross-validation. The segmentation results were evaluated by measuring the overlap, using the Dice similarity coefficient (DSC) and the mean distance error. Results: We obtained a DSC of 94.90 ± 2.12% for the sclera and the cornea, 94.72 ± 1.89% for the vitreous humor, and 85.16 ± 4.91% for the lens. The mean distance error was 0.26 ± 0.09 mm. The entire process took 14 seconds on average per eye. Conclusion: We provide a reliable and accurate tool that enables clinicians to automatically segment the sclera, the cornea, the vitreous humor, and the lens, using MRI. We additionally present a proof of concept for fully automatically segmenting eye pathology. This tool reduces the time needed for eye shape delineation and thus can help clinicians when planning eye treatment and confirming the extent of the tumor

3D CAPABILITIES OF PLEIADES SATELLITE

Directory of Open Access Journals (Sweden)

M. Bernard

2012-08-01

Full Text Available End of 2011 a new optical satellite, called Pléiades, was launched by the French space agency (CNES. It provides 20 km x 20 km images at 0.5 meters. This agile acquisition system is able to relocate very rapidly and scan the earth in any direction. The agility of the system offers the ability to acquire multi viewing angle images of the same area during the same orbit. This ability to capture, from a single stereoscopic pair, to a sequence of 25 images, allows enhancing the quality and the completeness of automatically extracted 3D maps. The aim of the study is to validate and quantify the capacity of the Pléiades system to perform 3D mapping. The analysis explores the advantages in terms of quality and automatism to use more than 2 stereoscopic images. In the last 10 years, automatic 3D processing of digital images became more and more popular and efficient. Thanks to aerial images with very large overlap and very high resolution satellite images, new methodologies and algorithms have been implemented to improve the quality and accuracy of automatic 3D processing. We propose to experiment the same type of approaches using Pléiades images to produce digital elevation models (DEM. A focus is made on analysing the 3D processing using video like (multi viewing acquisitions. Different reference sites with very accurate 3D control points are used to quantify the quality of the Pléiades DEM. Different acquisition modes are explored from a single stereo pair to a sequence of 17 images.

Automatic short axis orientation of the left ventricle in 3D ultrasound recordings

Science.gov (United States)

Pedrosa, João.; Heyde, Brecht; Heeren, Laurens; Engvall, Jan; Zamorano, Jose; Papachristidis, Alexandros; Edvardsen, Thor; Claus, Piet; D'hooge, Jan

2016-04-01

The recent advent of three-dimensional echocardiography has led to an increased interest from the scientific community in left ventricle segmentation frameworks for cardiac volume and function assessment. An automatic orientation of the segmented left ventricular mesh is an important step to obtain a point-to-point correspondence between the mesh and the cardiac anatomy. Furthermore, this would allow for an automatic division of the left ventricle into the standard 17 segments and, thus, fully automatic per-segment analysis, e.g. regional strain assessment. In this work, a method for fully automatic short axis orientation of the segmented left ventricle is presented. The proposed framework aims at detecting the inferior right ventricular insertion point. 211 three-dimensional echocardiographic images were used to validate this framework by comparison to manual annotation of the inferior right ventricular insertion point. A mean unsigned error of 8, 05° +/- 18, 50° was found, whereas the mean signed error was 1, 09°. Large deviations between the manual and automatic annotations (> 30°) only occurred in 3, 79% of cases. The average computation time was 666ms in a non-optimized MATLAB environment, which potentiates real-time application. In conclusion, a successful automatic real-time method for orientation of the segmented left ventricle is proposed.

Structure, magnetism and electronic properties in 3d-5d based double perovskite (Sr1-xYx)2FeIrO6.

Science.gov (United States)

Kharkwal, Kishor Chandra; Pramanik, Ashim Kumar

2017-10-17

The 3$d$-5$d$ based double perovskites are of current interest as they provide model system to study the interplay between electronic correlation ($U$) and spin-orbit coupling (SOC). Here we report detailed structural, magnetic and transport properties of doped double perovskite material (Sr$_{1-x}$Y$_x$)$_2$FeIrO$_6$ with $x$ $\\leq$ 0.2. With substitution of Y, system retains its original crystal structure but structural parameters modify with $x$ in nonmonotonic fashion. The magnetization data for Sr$_2$FeIrO$_6$ show antiferromagnetic type magnetic transition around 45 K, however, a close inspection in data indicates a weak magnetic phase transition around 120 K. No change of structural symmetry has been observed down to low temperature, although the lattice parameters show sudden changes around the magnetic transitions. Sr$_2$FeIrO$_6$ shows an insulating behavior over the whole temperature range which yet does not change with Y substitution. Nature of charge conduction is found to follow thermally activated Mott's variable range hopping and power law behavior for parent and doped samples, respectively. Interestingly, evolution of structural, magnetic and transport behavior in (Sr$_{1-x}$Y$_x$)$_2$FeIrO$_6$ is observed to reverse with $x$ $>$ 0.1 which is believed to arise due to change in transition metal ionic state. © 2017 IOP Publishing Ltd.

Automatic 3D City Modeling Using a Digital Map and Panoramic Images from a Mobile Mapping System

Directory of Open Access Journals (Sweden)

Hyungki Kim

2014-01-01

Full Text Available Three-dimensional city models are becoming a valuable resource because of their close geospatial, geometrical, and visual relationship with the physical world. However, ground-oriented applications in virtual reality, 3D navigation, and civil engineering require a novel modeling approach, because the existing large-scale 3D city modeling methods do not provide rich visual information at ground level. This paper proposes a new framework for generating 3D city models that satisfy both the visual and the physical requirements for ground-oriented virtual reality applications. To ensure its usability, the framework must be cost-effective and allow for automated creation. To achieve these goals, we leverage a mobile mapping system that automatically gathers high-resolution images and supplements sensor information such as the position and direction of the captured images. To resolve problems stemming from sensor noise and occlusions, we develop a fusion technique to incorporate digital map data. This paper describes the major processes of the overall framework and the proposed techniques for each step and presents experimental results from a comparison with an existing 3D city model.

Magnetism of cyano-bridged hetero-one-dimensional Ln3+-M3+ complexes (Ln3+ = Sm, Gd, Yb; M3+ = FeLS, Co).

Science.gov (United States)

Figuerola, Albert; Diaz, Carmen; Ribas, Joan; Tangoulis, Vassilis; Sangregorio, Claudio; Gatteschi, Dante; Maestro, Miguel; Mahía, José

2003-08-25

The reaction of Ln(NO(3))(3).aq with K(3)[Fe(CN)(6)] or K(3)[Co(CN)(6)] and 2,2'-bipyridine in water led to five one-dimensional complexes: trans-[M(CN)(4)(mu-CN)(2)Ln(H(2)O)(4) (bpy)](n)().XnH(2)O.1.5nbpy (M = Fe(3+) or Co(3+); Ln = Sm(3+), Gd(3+), or Yb(3+); X = 4 or 5). The structures for [Fe(3)(+)-Sm(3+)] (1), [Fe(3)(+)-Gd(3+)] (2), [Fe(3)(+)-Yb(3+)] (3), [Co(3)(+)-Gd(3+)] (4), and [Co(3)(+)-Yb(3+)] (5) have been solved; they crystallize in the triclinic space P1 and are isomorphous. The [Fe(3+)-Sm(3+)] complex is a ferrimagnet, its magnetic studies suggesting the onset of weak ferromagnetic 3-D ordering at 3.5 K. The [Fe(3+)-Gd(3+)] interaction is weakly antiferromagnetic. The isotropic nature of Gd(3+) allowed us to evaluate the exchange interaction (J = 0.77 cm(-)(1)).

Automatic construction of 3D-ASM intensity models by simulating image acquisition: application to myocardial gated SPECT studies.

Science.gov (United States)

Tobon-Gomez, Catalina; Butakoff, Constantine; Aguade, Santiago; Sukno, Federico; Moragas, Gloria; Frangi, Alejandro F

2008-11-01

Active shape models bear a great promise for model-based medical image analysis. Their practical use, though, is undermined due to the need to train such models on large image databases. Automatic building of point distribution models (PDMs) has been successfully addressed and a number of autolandmarking techniques are currently available. However, the need for strategies to automatically build intensity models around each landmark has been largely overlooked in the literature. This work demonstrates the potential of creating intensity models automatically by simulating image generation. We show that it is possible to reuse a 3D PDM built from computed tomography (CT) to segment gated single photon emission computed tomography (gSPECT) studies. Training is performed on a realistic virtual population where image acquisition and formation have been modeled using the SIMIND Monte Carlo simulator and ASPIRE image reconstruction software, respectively. The dataset comprised 208 digital phantoms (4D-NCAT) and 20 clinical studies. The evaluation is accomplished by comparing point-to-surface and volume errors against a proper gold standard. Results show that gSPECT studies can be successfully segmented by models trained under this scheme with subvoxel accuracy. The accuracy in estimated LV function parameters, such as end diastolic volume, end systolic volume, and ejection fraction, ranged from 90.0% to 94.5% for the virtual population and from 87.0% to 89.5% for the clinical population.

Ultra-small Fe3O4 nanocrystals decorated on 2D graphene nanosheets with excellent cycling stability as anode materials for lithium ion batteries

International Nuclear Information System (INIS)

Ren, Manman; Yang, Mingzhi; Liu, Weiliang; Li, Mei; Su, Liwei; Qiao, Congde; Wu, Xianbin; Ma, Houyi

2016-01-01

Graphical abstract: Ultra-small Fe 3 O 4 nanocrystals decorated on 2D graphene nanosheets with excellent cycling stability as anode materials for lithium ion batteries Manman Ren, Mingzhi Yang, Weiliang Liu, Mei Li, Liwei Su, Congde Qiao, Xianbin Wu, Houyi Ma Ultra-small Fe 3 O 4 nanocrystals/graphene nanosheets composites demonstrate excellent long-term cycling stability at high-rate. - Abstract: Ultra-small Fe 3 O 4 nanocrystals (NCs)/garphene nanosheets (GNSs) composites have been synthesized through a facile gel-like film (GF) assisted method in this work. Fe 3 O 4 NCs with particle size ∼10 nm homogeneously dispersed on 2D GNSs. Profiting from the ultra-small Fe 3 O 4 NCs and GNSs, the composites demonstrate superior long-term and high-rate performance as anode materials for lithium ion batteries. Even at the current density of 5 A g −1 , the reversible capacity still maintains 323.4 mAh g −1 after 700 cycles. This work might enlighten us on exploring preferable strategies to develop advanced metal oxides NCs/GNSs composites anode materials for lithium ion batteries or other energy storage devices.

Facile fabrication of carbon microspheres decorated with B(OH) 3 and α-Fe 2 O 3 nanoparticles: superior microwave absorption

KAUST Repository

Zhong, Bo

2017-06-02

We demonstrate that novel three-dimensional (3D) B(OH)3 and α-Fe2O3 nanoparticles decorated carbon microspheres (B(OH)3/α-Fe2O3-CMSs) can be fabricated via a facile thermal treatment process. The carbon microspheres with diameter of 1 to 3 μm and decorated B(OH)3 and α-Fe2O3 nanoparticles with diameters of several to tens of nanometers are successfully fabricated. These novel 3D B(OH)3/α-Fe2O3-CMS composites exhibit enhanced microwave absorption with tunable strong absorption wavebands in the frequency range of 2–18 GHz. They have a minimum reflection loss (RL) value of -52.69 dB at a thickness of 3.0 mm, and the effective absorption bandwidth for RL less than -10 dB is as large as 5.64 GHz. The enhanced microwave absorption performance arises from the synergy of the impedance matching caused by the B(OH)3 nanoparticles, dielectric loss as well as the enhancement of multiple reflection among 3D α-Fe2O3 nanocrystals. These results provide a new strategy to tune electromagnetic properties and enhance the capacity of high-efficient microwave absorbers.

Facile fabrication of carbon microspheres decorated with B(OH) 3 and α-Fe 2 O 3 nanoparticles: superior microwave absorption

KAUST Repository

Zhong, Bo; Wang, Chaojun; Yu, Yuanlie; Xia, Long; Wen, Guangwu

2017-01-01

We demonstrate that novel three-dimensional (3D) B(OH)3 and α-Fe2O3 nanoparticles decorated carbon microspheres (B(OH)3/α-Fe2O3-CMSs) can be fabricated via a facile thermal treatment process. The carbon microspheres with diameter of 1 to 3 μm and decorated B(OH)3 and α-Fe2O3 nanoparticles with diameters of several to tens of nanometers are successfully fabricated. These novel 3D B(OH)3/α-Fe2O3-CMS composites exhibit enhanced microwave absorption with tunable strong absorption wavebands in the frequency range of 2–18 GHz. They have a minimum reflection loss (RL) value of -52.69 dB at a thickness of 3.0 mm, and the effective absorption bandwidth for RL less than -10 dB is as large as 5.64 GHz. The enhanced microwave absorption performance arises from the synergy of the impedance matching caused by the B(OH)3 nanoparticles, dielectric loss as well as the enhancement of multiple reflection among 3D α-Fe2O3 nanocrystals. These results provide a new strategy to tune electromagnetic properties and enhance the capacity of high-efficient microwave absorbers.

Comparison of T1-weighted 2D TSE, 3D SPGR, and two-point 3D Dixon MRI for automated segmentation of visceral adipose tissue at 3 Tesla.

Science.gov (United States)

Fallah, Faezeh; Machann, Jürgen; Martirosian, Petros; Bamberg, Fabian; Schick, Fritz; Yang, Bin

2017-04-01

To evaluate and compare conventional T1-weighted 2D turbo spin echo (TSE), T1-weighted 3D volumetric interpolated breath-hold examination (VIBE), and two-point 3D Dixon-VIBE sequences for automatic segmentation of visceral adipose tissue (VAT) volume at 3 Tesla by measuring and compensating for errors arising from intensity nonuniformity (INU) and partial volume effects (PVE). The body trunks of 28 volunteers with body mass index values ranging from 18 to 41.2 kg/m 2 (30.02 ± 6.63 kg/m 2 ) were scanned at 3 Tesla using three imaging techniques. Automatic methods were applied to reduce INU and PVE and to segment VAT. The automatically segmented VAT volumes obtained from all acquisitions were then statistically and objectively evaluated against the manually segmented (reference) VAT volumes. Comparing the reference volumes with the VAT volumes automatically segmented over the uncorrected images showed that INU led to an average relative volume difference of -59.22 ± 11.59, 2.21 ± 47.04, and -43.05 ± 5.01 % for the TSE, VIBE, and Dixon images, respectively, while PVE led to average differences of -34.85 ± 19.85, -15.13 ± 11.04, and -33.79 ± 20.38 %. After signal correction, differences of -2.72 ± 6.60, 34.02 ± 36.99, and -2.23 ± 7.58 % were obtained between the reference and the automatically segmented volumes. A paired-sample two-tailed t test revealed no significant difference between the reference and automatically segmented VAT volumes of the corrected TSE (p = 0.614) and Dixon (p = 0.969) images, but showed a significant VAT overestimation using the corrected VIBE images. Under similar imaging conditions and spatial resolution, automatically segmented VAT volumes obtained from the corrected TSE and Dixon images agreed with each other and with the reference volumes. These results demonstrate the efficacy of the signal correction methods and the similar accuracy of TSE and Dixon imaging for automatic volumetry of VAT at 3 Tesla.

Molecular [(Fe3)–(Fe3)] and [(Fe4)–(Fe4)] coordination cluster pairs as single or composite arrays.

Science.gov (United States)

Sañudo, E Carolina; Uber, Jorge Salinas; Pons Balagué, Alba; Roubeau, Olivier; Aromí, Guillem

2012-08-06

The synthesis of molecular cluster pairs is a challenge for coordination chemists due to the potential applications of these species in molecular spintronics or quantum computing. The ligand H(4)L, 1,3-bis-(3-oxo-3-(2-hydroxyphenyl)-propionyl)-2-methoxybenzene, has been successfully used to obtain a series of such complexes using the basic Fe(III) trinuclear carboxylates as starting materials. Synthetic control has allowed the isolation of the two molecular cluster pairs that form the composite [Fe(4)O(2)(PhCO(2))(6)(H(2)L)(pz)](2)[Fe(3)O(PhCO(2))(5)(py)(H(2)L)](2) (1). The dimers of trinuclear units, [Fe(3)O(PhCO(2))(5)(H(2)O)(H(2)L)](2) (2) and [Fe(3)O(o-MePhCO(2))(5)(H(2)L)(py)](2) (3), and the dimers of tetranuclear units, [Fe(4)O(2)(PhCO(2))(6)(H(2)L)(pz)](2) (4) and [Fe(4)O(2)(o-MePhCO(2))(6)(H(2)L)(pz)](2) (5), are presented here. The magnetic properties of the reported aggregates show that they are pairs of semi-independent clusters weakly interacting magnetically as required for two-qubit quantum gates.

Large Charge-Transfer Energy in LiFePO4 Revealed by Full-Multiplet Calculation for the Fe L3 -edge Soft X-ray Emission Spectra.

Science.gov (United States)

Asakura, Daisuke; Nanba, Yusuke; Makinose, Yuki; Matsuda, Hirofumi; Glans, Per-Anders; Guo, Jinghua; Hosono, Eiji

2018-04-17

We analyzed the Fe 3d electronic structure in LiFePO 4 /FePO 4 (LFP/FP) nanowire with a high cyclability by using soft X-ray emission spectroscopy (XES) combined with configuration-interaction full-multiplet (CIFM) calculation. The ex situ Fe L 2,3 -edge resonant XES (RXES) spectra for LFP and FP are ascribed to oxidation states of Fe 2+ and Fe 3+ , respectively. CIFM calculations for Fe 2+ and Fe 3+ states reproduced the Fe L 3 RXES spectra for LFP and FP, respectively. In the calculations for both states, the charge-transfer energy was considerably larger than those for typical iron oxides, indicating very little electron transfer from the O 2p to Fe 3d orbitals and a weak hybridization on the Fe-O bond during the charge-discharge reactions. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Photoelectron spectroscopy study of Fe-diluted Au-Fe alloys

CERN Document Server

Nahm, T U; Choi, B; Park, J S; Oh, S J; Cho, E J

2003-01-01

The electronic structure of Fe-diluted Au-Fe alloys has been studied by taking core-level and valence-band spectra using x-ray photoemission spectroscopy and synchrotron radiation. From the core-level spectroscopy, we found that the Fe 2p spectrum is composed of d sup 6 and d sup 7 multiplets from Fe impurity atoms. This behaviour is qualitatively discussed within the context of electron-electron interaction. In order to explore the electron-correlation effects in the valence band, we obtained Fe 3d partial spectral weights by taking advantage of the Cooper-minimum phenomenon of an Au 5d photoionization cross section. It was found that the spin-down states have an appreciable amount of spectral weights throughout the host Au 5d band, contrary to previous one-electron calculations predicting two-peak structure of the Fe 3d states. We suggest that this discrepancy results from the correlation effect of the Fe 3d electrons.

An assessment of finite element synthesis model using 3D FEM

International Nuclear Information System (INIS)

Jagannathan, V.; Rastogi, B.P

1983-01-01

For the solution of multigroup diffusion theory equations a code system called FEMSYN has been developed. The code FEMSYN incorporates a finite difference (FD) module, a finite element (FE) module and one module based on single channel flux synthesis (SCFS) method, which uses trial functions generated by either FD or FE method. The 3D problems can be tackled by all the three modules. The 3D FE solutions are cheaper in comparison with fine mesh FD computations and are quite accurate. The accuracy is improved by proper choice of rectangular and triangular right prismatic elements and polynomial order in case of 3D FE analyses. Synthesis method using FE trial functions provides the fastest means of solution for 3D problems. In this paper, the FE synthesis method has been compared with 3D FE technique for the case of IAEA PWR benchmark problem. It is concluded from the above comparison that FE synthesis method can give at negligible computational efforts, accurate eigenvalue estimates and satisfactory prediction of reactor core power profiles

Self-Poling of BiFeO3 Thick Films.

Science.gov (United States)

Khomyakova, Evgeniya; Sadl, Matej; Ursic, Hana; Daniels, John; Malic, Barbara; Bencan, Andreja; Damjanovic, Dragan; Rojac, Tadej

2016-08-03

Bismuth ferrite (BiFeO3) is difficult to pole because of the combination of its high coercive field and high electrical conductivity. This problem is particularly pronounced in thick films. The poling, however, must be performed to achieve a large macroscopic piezoelectric response. This study presents evidence of a prominent and reproducible self-poling effect in few-tens-of-micrometer-thick BiFeO3 films. Direct and converse piezoelectric measurements confirmed that the as-sintered BiFeO3 thick films yield d33 values of up to ∼20 pC/N. It was observed that a significant self-poling effect only appears in cases when the films are heated and cooled through the ferroelectric-paraelectric phase transition (Curie temperature TC ∼ 820 °C). These self-poled films exhibit a microstructure with randomly oriented columnar grains. The presence of a compressive strain gradient across the film thickness cooled from above the TC was experimentally confirmed and is suggested to be responsible for the self-poling effect. Finally, the macroscopic d33 response of the self-poled BiFeO3 film was characterized as a function of the driving-field frequency and amplitude.

Structure, magnetism and electronic properties in 3d-5d based double perovskite ({Sr_{1-x}} Y x )2FeIrO6

Science.gov (United States)

Kharkwal, K. C.; Pramanik, A. K.

2017-12-01

The 3d-5d based double perovskites are of current interest as they provide model systems to study the interplay between electronic correlation (U) and spin-orbit coupling (SOC). Here, we report detailed structural, magnetic and transport properties of doped double perovskite material (Sr1-x Y x )2FeIrO6 with x ≤slant 0.2 . With substitution of Y, the system retains its original crystal structure but structural parameters change with x in nonmonotonic fashion. The magnetization data for Sr2FeIrO6 show antiferromagnetic type magnetic transition around 45 K however, a close inspection of the data indicates a weak magnetic phase transition around 120 K. No change of structural symmetry has been observed down to low temperature, although the lattice parameters show sudden changes around the magnetic transitions. Sr2FeIrO6 shows an insulating behavior over the whole temperature range, which nevertheless does not change with Y substitution. The nature of charge conduction is found to follow thermally activated Mott’s variable range hopping and power law behavior for parent and doped samples, respectively. Interestingly, evolution of structural, magnetic and transport behavior in (Sr1-x Y x )2FeIrO6 is observed to reverse with x > 0.1 , which is believed to arise due to a change in the transition metal ionic state.

A new method of 3-D cephalometry Part I: the anatomic Cartesian 3-D reference system.

NARCIS (Netherlands)

Swennen, G.R.J.; Schutyser, F.A.C.; Barth, E.L.; Groeve, P. De; Mey, A. De

2006-01-01

The purpose of this study was to present a new innovative three-dimensional (3-D) cephalometric method. Part I deals with the set-up and validation of a voxel-based semi-automatic 3-D cephalometric reference system. The CT data (DICOM 3.0 files) of 20 control patients with normal skeletal

Calculation of the electronic and magnetic structures of 3d impurities in the Hcp Fe matrix

International Nuclear Information System (INIS)

Franca, Fernando

1995-01-01

In this work we investigate the local magnetic properties and the electronic structure of HCP Fe, as well introducing transition metals atoms 3d (Cs, Ti, Cr, Mn, Co, Ni, Cu, Zn) in HCP iron matrix. We employed the discrete variational method (DVM), which is an orbital molecular method which incorporate the Hartree-Fock-Slater theory and the linear combination of atomic orbitals (LCAO), in the self-consistent charge approximation and the local density approximation of Von Barth and Hedin to the exchange-correlation potential. We used the embedded cluster model to investigate the electronic structure and the local magnetic properties for the central atom of a cluster of 27 atoms immersed in the microcrystal representing the HCP Fe. (author)

Manipulation of isolated brain nerve terminals by an external magnetic field using D-mannose-coated γ-Fe2O3 nano-sized particles and assessment of their effects on glutamate transport.

Science.gov (United States)

Borisova, Tatiana; Krisanova, Natalia; Borуsov, Arsenii; Sivko, Roman; Ostapchenko, Ludmila; Babic, Michal; Horak, Daniel

2014-01-01

The manipulation of brain nerve terminals by an external magnetic field promises breakthroughs in nano-neurotechnology. D-Mannose-coated superparamagnetic nanoparticles were synthesized by coprecipitation of Fe(II) and Fe(III) salts followed by oxidation with sodium hypochlorite and addition of D-mannose. Effects of D-mannose-coated superparamagnetic maghemite (γ-Fe2O3) nanoparticles on key characteristics of the glutamatergic neurotransmission were analysed. Using radiolabeled L-[(14)C]glutamate, it was shown that D-mannose-coated γ-Fe2O3 nanoparticles did not affect high-affinity Na(+)-dependent uptake, tonic release and the extracellular level of L-[(14)C]glutamate in isolated rat brain nerve terminals (synaptosomes). Also, the membrane potential of synaptosomes and acidification of synaptic vesicles was not changed as a result of the application of D-mannose-coated γ-Fe2O3 nanoparticles. This was demonstrated with the potential-sensitive fluorescent dye rhodamine 6G and the pH-sensitive dye acridine orange. The study also focused on the analysis of the potential use of these nanoparticles for manipulation of nerve terminals by an external magnetic field. It was shown that more than 84.3 ± 5.0% of L-[(14)C]glutamate-loaded synaptosomes (1 mg of protein/mL) incubated for 5 min with D-mannose-coated γ-Fe2O3 nanoparticles (250 µg/mL) moved to an area, in which the magnet (250 mT, gradient 5.5 Т/m) was applied compared to 33.5 ± 3.0% of the control and 48.6 ± 3.0% of samples that were treated with uncoated nanoparticles. Therefore, isolated brain nerve terminals can be easily manipulated by an external magnetic field using D-mannose-coated γ-Fe2O3 nanoparticles, while the key characteristics of glutamatergic neurotransmission are not affected. In other words, functionally active synaptosomes labeled with D-mannose-coated γ-Fe2O3 nanoparticles were obtained.

Influence of Fe{sub 3}O{sub 4}/Fe-phthalocyanine decorated graphene oxide on the microwave absorbing performance

Energy Technology Data Exchange (ETDEWEB)

Li, Jingwei; Wei, Junji; Pu, Zejun; Xu, Mingzhen; Jia, Kun, E-mail: jiakun@uestc.edu.cn; Liu, Xiaobo, E-mail: liuxb@uestc.edu.cn

2016-02-01

Novel graphene oxide@Fe{sub 3}O{sub 4}/iron phthalocyanine (GO@Fe{sub 3}O{sub 4}/FePc) hybrid materials were prepared through a facile one-step solvothermal method with graphene oxide (GO) sheets as template in ethylene glycol. The morphology and structure of the hybrid materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectrophotometer (FTIR) and X-ray diffraction (XRD), respectively. The results indicated that the monodispersed Fe{sub 3}O{sub 4}/FePc hybrid microspheres were uniformly self-assembled along the surface of GO sheets through electrostatic attraction and the morphology can be tuned by controlling the amount of 4,4′-bis(3,4-dicyanophenoxy)biphenyl (BPH). As the BPH content increases, magnetization measurement of the GO@Fe{sub 3}O{sub 4}/FePc hybrid materials showed that the coercivity increased, while saturation magnetizations decreased. Electromagnetic properties of the hybrid materials were measured in the range of 0.5–18.0 GHz. The microwave absorbing performance enhanced with the increase of BPH content and a maximum reflection loss of −27.92 dB was obtained at 10.8 GHz when the matching thickness was 2.5 mm. Therefore, the novel electromagnetic hybrid materials can be considered as potential materials in the microwave absorbing field. - Highlights: • Graphene oxide was employed to support Fe{sub 3}O{sub 4}/iron phthalocyanine hybrid particles. • The morphology and magnetic properties of obtained particles can be readily tuned. • A maximum microwave reflection loss of −27.92 dB was obtained at 10.8 GHz.

57Fe Mössbauer study of unusual magnetic structure of multiferroic 3R-AgFeO2

Science.gov (United States)

Sobolev, A.; Rusakov, V.; Moskvin, A.; Gapochka, A.; Belik, A.; Glazkova, I.; Akulenko, A.; Demazeau, G.; Presniakov, I.

2017-07-01

We report new results of a 57Fe Mössbauer study of hyperfine magnetic interactions in the layered multiferroic 3R-AgFeO2 demonstrating two magnetic phase transitions at T N1 and T N2. The asymptotic value β *  ≈  0.34 for the critical exponent obtained from the temperature dependence of the hyperfine field H hf(T) at 57Fe the nuclei below T N1  ≈  14 K indicates that 3R-AgFeO2 shows quasi-3D critical behavior. The spectra just above T N1 (T N1  formula to describe the dependence of H anis on the distortions of the (FeO6) clusters. Analysis of different mechanisms of spin and hyperfine interactions in 3R-AgFeO2 and its structural analogue CuFeO2 points to a specific role played by the topology of the exchange coupling and the oxygen polarization in the delafossite-like structures.

Electronic and magnetic properties of Fe-, Co-, and Ni-decorated BC3: A first-principles study

Science.gov (United States)

Zhu, Jingzhong; Zhao, Yinchang; Zulfiqar, Muhammad; Zeng, Shuming; Ni, Jun

2018-05-01

The electronic and magnetic properties of Fe-, Co-, and Ni-decorated two dimensional (2D) BC3 are systematically investigated by first-principles calculations. We find that the Fe, Co, and Ni atoms can be strongly adsorbed on the hollow sites of 2D BC3. Fe and Co adatoms are more stable when adsorbed on the hollow sites of the carbon rings in the 2D BC3, while the hollow sites of boron-carbon rings in the 2D BC3 are the most stable sites for the adsorption of Ni adatoms. These proposed metal-BC3 complexes exhibit interesting electronic and magnetic behaviors. In particular, the Fe-BC3 and Co-BC3 complexes are metals with magnetic ground states , while the Ni-BC3 complex behaves as a nonmagnetic semiconductor with a direct bandgap. Furthermore, our magnetic analysis reveals that induced magnetism in the Fe-BC3 and Co-BC3 complexes arises from their local magnetic moments. Functionalization of 2D BC3 through these metal-adatom adsorption appears to be a promising way to extend its applications.

Polyaniline/Fe3O4-RGO Nanocomposites for Microwave Absorption

Science.gov (United States)

Mathew, Jithin; Sathishkumar, M.; Kothurkar, Nikhil K.; Senthilkumar, R.; Sabarish Narayanan, B.

2018-02-01

Fe3O4 nanoparticles were synthesized by co-precipitation of ferric chloride (FeCl3) and ferrous chloride (FeCl2). Reduced graphene oxide (RGO) was prepared by reducing the graphene oxide, which was synthesized by Hummer’s method, using hydrazine hydrate. Three nanocomposites based on sodium dodecyl benzene sulphonate (SDBS)-doped polyaniline were synthesized through in situ polymerization in the presence of the fillers (i) Fe3O4, (ii) reduced graphene oxide (RGO) and (iii) Fe3O4-decorated RGO respectively. The synthesized PANI and the composites were characterized by X-ray diffraction, Fourier transform infrared spectroscopy and transmission electron microscopy. Their microstructures, electrical conductivities, and EMI shielding effectiveness were studied. The nanocomposite containing 10 % RGO showed the maximum electrical conductivity and the one with 10 % RGO and 10 % Fe3O4 showed the maximum EMI shielding effectiveness of 7.5 dB for a 1 mm thick sample.

AUTOMATIC MESH GENERATION OF 3—D GEOMETRIC MODELS

Institute of Scientific and Technical Information of China (English)

刘剑飞

2003-01-01

In this paper the presentation of the ball-packing method is reviewed, and a schemeto generate mesh for complex 3-D geometric models is given, which consists of 4 steps: (1) createnodes in 3-D models by ball-packing method, (2) connect nodes to generate mesh by 3-D Delaunaytriangulation, (3) retrieve the boundary of the model after Delaunay triangulation, (4) improve themesh.

Self-assembly of nano/micro-structured Fe3O4 microspheres among 3D rGO/CNTs hierarchical networks with superior lithium storage performances

International Nuclear Information System (INIS)

Liu, Jinlong; Feng, Haibo; Wang, Xipeng; Qian, Dong; Jiang, Jianbo; Li, Junhua; Peng, Sanjun; Deng, Miao; Liu, Youcai

2014-01-01

Nano/micro-structured Fe 3 O 4 microspheres among three-dimensional (3D) reduced graphene oxide (rGO)/carbon nanotubes (CNTs) hierarchical networks (the ternary composite is denoted as rGCFs) have been synthesized using a facile, self-assembled and one-pot hydrothermal approach. The rGCFs composite exhibits superior lithium storage performances: initial discharge and charge capacities of 1452 and 1036 mAh g −1 , respectively, remarkable rate capability at current densities from 100 mA g −1 to 10 A g −1 and outstanding cycling performance up to 200 cycles. The highly enhanced electrochemical performances of rGCFs depend heavily on the robust 3D rGO/CNTs hierarchical networks, the stable nano/microstructures of active Fe 3 O 4 microspheres and the positive synergistic effects of building components. The systematic structure characterizations and electrochemical investigations provide insightful understanding towards the relationship between structure/morphology and lithium storage performances, which may pave the way for the rational design of composite materials with desirable goals. (papers)

Electronic structure of multiferroic BiFeO3 by resonant soft-x-ray emission spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Higuchi, Tohru; Higuchi, T.; Liu, Y.-S.; Yao, P.; Glans, P.-A.; Guo, Jinghua; Chang, C.; Wu, Z.; Sakamoto, W.; Itoh, N.; Shimura, T.; Yogo, T.; Hattori, T.

2008-07-11

The electronic structure of multiferroic BiFeO{sub 3} has been studied using soft-X-ray emission spectroscopy. The fluorescence spectra exhibit that the valence band is mainly composed of O 2p state hybridized with Fe 3d state. The band gap corresponding to the energy separation between the top of the O 2p valence band and the bottom of the Fe 3d conduction band is 1.3 eV. The soft-X-ray Raman scattering reflects the features due to charge transfer transition from O 2p valence band to Fe 3d conduction band. These findings are similar to the result of electronic structure calculation by density functional theory within the local spin-density approximation that included the effect of Coulomb repulsion between localized d states.

Synthesis, structure and magnetic properties of a new iron phosphonate-oxalate with 3D framework: [Fe(O3PCH3)(C2O4)0.5(H2O)

International Nuclear Information System (INIS)

Zhang Yangyang; Qi Yue; Zhang Ying; Liu Ziyu; Zhao Yinfeng; Liu Zhongmin

2007-01-01

A new iron phosphonate-oxalate [Fe(O 3 PCH 3 )(C 2 O 4 ) 0.5 (H 2 O)] (1), has been synthesized under hydrothermal condition. The single-crystal X-ray diffraction studies reveal that 1 consists of layers of vertex-linked FeO 6 octahedra and O 3 PC tetrahedra, which are further connected by bis-chelate oxalate bridges, giving to a 3D structure with 10-membered channels. Crystal data: monoclinic, P2 1 /n (no. 14), a=4.851(2)A, b=16.803(7)A, c=7.941(4)A, β=107.516(6) o , V=617.2(5)A 3 , Z=4, R 1 =0.0337 and wR 2 =0.0874 for 1251 reflections [I>2σ(I)]. Mossbauer spectroscopy measurement confirms the existence of high-spin Fe(III) in 1. Magnetic studies show that 1 exhibits weak ferromagnetism with T N =30K due to a weak spin canting

The solubility and site preference of Fe3+ in Li7−3xFexLa3Zr2O12 garnets

International Nuclear Information System (INIS)

Rettenwander, D.; Geiger, C.A.; Tribus, M.; Tropper, P.; Wagner, R.; Tippelt, G.; Lottermoser, W.; Amthauer, G.

2015-01-01

A series of Fe 3+ -bearing Li 7 La 3 Zr 2 O 12 (LLZO) garnets was synthesized using solid-state synthesis methods. The synthetic products were characterized compositionally using electron microprobe analysis and inductively coupled plasma optical emission spectroscopy (ICP-OES) and structurally using X-ray powder diffraction and 57 Fe Mössbauer spectroscopy. A maximum of about 0.25 Fe 3+ pfu could be incorporated in Li 7−3x Fe x La 3 Zr 2 O 12 garnet solid solutions. At Fe 3+ concentrations lower than about 0.16 pfu, both tetragonal and cubic garnets were obtained in the synthesis experiments. X-ray powder diffraction analysis showed only a garnet phase for syntheses with starting materials having intended Fe 3+ contents lower than 0.52 Fe 3+ pfu. Back-scattered electron images made with an electron microprobe also showed no phase other than garnet for these compositions. The lattice parameter, a 0 , for all solid-solution garnets is similar with a value of a 0 ≈12.98 Å regardless of the amount of Fe 3+ . 57 Fe Mössbauer spectroscopic measurements indicate the presence of poorly- or nano-crystalline FeLaO 3 in syntheses with Fe 3+ contents greater than 0.16 Fe 3+ pfu. The composition of different phase pure Li 7−3x Fe x La 3 Zr 2 O 12 garnets, as determined by electron microprobe (Fe, La, Zr) and ICP-OES (Li) measurements, give Li 6.89 Fe 0.03 La 3.05 Zr 2.01 O 12 , Li 6.66 Fe 0.06 La 3.06 Zr 2.01 O 12 , Li 6.54 Fe 0.12 La 3.01 Zr 1.98 O 12 , and Li 6.19 Fe 0.19 La 3.02 Zr 2.04 O 12 . The 57 Fe Mössbauer spectrum of cubic Li 6.54 Fe 0.12 La 3.01 Zr 1.98 O 12 garnet indicates that most Fe 3+ occurs at the special crystallographic 24d position, which is the standard tetrahedrally coordinated site in garnet. Fe 3+ in smaller amounts occurs at a general 96h site, which is only present for certain Li-oxide garnets, and in Li 6.54 Fe 0.12 La 3.01 Zr 1.98 O 12 this Fe 3+ has a distorted 4-fold coordination. - Graphical abstract: Cubic nominally Li 7 La 3 Zr 2 O

CHARACTERIZATION AND AUTOMATIC COUNTING OF F.I.S.H. SIGNALS IN 3-D TISSUE IMAGES

Directory of Open Access Journals (Sweden)

Umesh PS Adiga

2011-05-01

Full Text Available The evaluation of malignancy-related features often helps to determine the prognoses for patients with carcinomas. One technique, which is becoming increasingly important for assessing such prognostic features is that of Fluorescence in situ Hybridization (FISH. By counting the number of FISH signals in a stack of 2- D images of a tumor (which together constitute the 3-D image volume, it is possible to determine whether there has been any loss or gain of the target DNA sequences and thereby evaluate the stage of the disease. However, visual counting of the FISH signals in this way is a tedious, fatiguing and time-consuming task. Therefore, we have developed an automated system for the quantitative evaluation of FISH signals. We present and discuss the implementation of an image processing module that segments, characterizes and counts the FISH signals in 3-D images of thick prostate tumor tissue specimens. Possible errors in the automatic counting of signals are listed and ways to circumvent these errors are described. We define a feature vector for a FISH signal and describe how we have used the weighted feature vector to segment specific signals from noise artifacts. In addition, we present a method, which allows overlapping FISH signals to be distinguished by fitting a local Gaussian model around the intensity profile and studying the feature vector of each model. Our complete image processing module overcomes the problems of manual counting of FISH signals in 3-D images of tumor specimens, thereby providing improved diagnostic and prognostic capability in qualitative diagnostic pathology.

Optical spectroscopic study of multiferroic BiFeO3 and LuFe2O4

Science.gov (United States)

Xu, Xiaoshan

2010-03-01

Iron-based multiferroics such as BiFeO3 and LuFe2O4 exhibit the highest magnetic and ferroelectric ordering temperatures among known multiferroics. LuFe2O4 is a frustrated system with several phase transitions that result in electronically driven multiferroicity. To understand how this peculiar multiferroic mechanism correlates with magnetism, we studied electronic excitations by optical spectroscopy and other complementary techniques. We show that the charge order, which determines the dielectric properties, is due to the ``order by fluctuation'' mechanism, evidenced by the onset of charge fluctuation well below the charge ordering transition. We also find a low temperature monoclinic distortion driven by both temperature and magnetic field, indicating strong coupling between structure, magnetism and charge order. BiFeO3 is the only known single phase multiferroics with room temperature magnetism and ferroelectricity. To investigate the spin-charge coupling, we measured the optical properties of BiFeO3. We find that the absorption onset occurs due to on-site Fe^3+ excitations at 1.41 and 1.90 eV. Temperature and magnetic-field-induced spectral changes reveal complex interactions between on-site crystal-field and magnetic excitations in the form of magnon sidebands. The sensitivity of the magnon sidebands allows us to map out the magnetic-field temperature phase diagram which demonstrates optical evidence for spin spiral quenching above 20 T and suggests a spin domain reorientation near 10 T. Work done in collaboration with T.V. Brinzari, R.C. Rai, M. Angst, R.P. Hermann, A.D. Christianson, J.-W. Kim, Z. Islam, B.C. Sales, D. Mandrus, S. Lee, Y.H. Chu, L. W. Martin, A. Kumar, R. Ramesh, S.W. Cheong, S. McGill, and J.L. Musfeldt.

SU-D-201-05: On the Automatic Recognition of Patient Safety Hazards in a Radiotherapy Setup Using a Novel 3D Camera System and a Deep Learning Framework

Energy Technology Data Exchange (ETDEWEB)

Santhanam, A; Min, Y; Beron, P; Agazaryan, N; Kupelian, P; Low, D [UCLA, Los Angeles, CA (United States)

2016-06-15

Purpose: Patient safety hazards such as a wrong patient/site getting treated can lead to catastrophic results. The purpose of this project is to automatically detect potential patient safety hazards during the radiotherapy setup and alert the therapist before the treatment is initiated. Methods: We employed a set of co-located and co-registered 3D cameras placed inside the treatment room. Each camera provided a point-cloud of fraxels (fragment pixels with 3D depth information). Each of the cameras were calibrated using a custom-built calibration target to provide 3D information with less than 2 mm error in the 500 mm neighborhood around the isocenter. To identify potential patient safety hazards, the treatment room components and the patient’s body needed to be identified and tracked in real-time. For feature recognition purposes, we used a graph-cut based feature recognition with principal component analysis (PCA) based feature-to-object correlation to segment the objects in real-time. Changes in the object’s position were tracked using the CamShift algorithm. The 3D object information was then stored for each classified object (e.g. gantry, couch). A deep learning framework was then used to analyze all the classified objects in both 2D and 3D and was then used to fine-tune a convolutional network for object recognition. The number of network layers were optimized to identify the tracked objects with >95% accuracy. Results: Our systematic analyses showed that, the system was effectively able to recognize wrong patient setups and wrong patient accessories. The combined usage of 2D camera information (color + depth) enabled a topology-preserving approach to verify patient safety hazards in an automatic manner and even in scenarios where the depth information is partially available. Conclusion: By utilizing the 3D cameras inside the treatment room and a deep learning based image classification, potential patient safety hazards can be effectively avoided.

SU-D-201-05: On the Automatic Recognition of Patient Safety Hazards in a Radiotherapy Setup Using a Novel 3D Camera System and a Deep Learning Framework

International Nuclear Information System (INIS)

Santhanam, A; Min, Y; Beron, P; Agazaryan, N; Kupelian, P; Low, D

2016-01-01

Purpose: Patient safety hazards such as a wrong patient/site getting treated can lead to catastrophic results. The purpose of this project is to automatically detect potential patient safety hazards during the radiotherapy setup and alert the therapist before the treatment is initiated. Methods: We employed a set of co-located and co-registered 3D cameras placed inside the treatment room. Each camera provided a point-cloud of fraxels (fragment pixels with 3D depth information). Each of the cameras were calibrated using a custom-built calibration target to provide 3D information with less than 2 mm error in the 500 mm neighborhood around the isocenter. To identify potential patient safety hazards, the treatment room components and the patient’s body needed to be identified and tracked in real-time. For feature recognition purposes, we used a graph-cut based feature recognition with principal component analysis (PCA) based feature-to-object correlation to segment the objects in real-time. Changes in the object’s position were tracked using the CamShift algorithm. The 3D object information was then stored for each classified object (e.g. gantry, couch). A deep learning framework was then used to analyze all the classified objects in both 2D and 3D and was then used to fine-tune a convolutional network for object recognition. The number of network layers were optimized to identify the tracked objects with >95% accuracy. Results: Our systematic analyses showed that, the system was effectively able to recognize wrong patient setups and wrong patient accessories. The combined usage of 2D camera information (color + depth) enabled a topology-preserving approach to verify patient safety hazards in an automatic manner and even in scenarios where the depth information is partially available. Conclusion: By utilizing the 3D cameras inside the treatment room and a deep learning based image classification, potential patient safety hazards can be effectively avoided.

Solvothermal synthesis and good microwave absorbing properties for magnetic porous-Fe3O4/graphene nanocomposites

Directory of Open Access Journals (Sweden)

Xiaojun Zeng

2017-05-01

Full Text Available The magnetic porous-Fe3O4/graphene nanocomposites have been fabricated by a facile solvothermal method. The porous Fe3O4 nanospheres are embedded uniformly in the graphene oxide (GO sheets to form a 3D Fe3O4/GO nanocomposite network. The dielectric properties for the Fe3O4/GO composites can be greatly improved by the 7 wt% GO additions. Good impedance matching can be also obtained in these Fe3O4/GO composites, which is proved to dominate their excellent microwave absorbing properties including the minimum reflection loss (RL value of -43.7 dB at 6.8 GHz with a sample thickness of 5 mm and a broad absorption bandwidth of 5.92 GHz (below -10 dB. These porous-Fe3O4/GO composites also exhibit the good structural stability and low density, which shows their great potential application in high-performance electromagnetic microwave-absorbing materials.

3D Model Optimization of Four-Facet Drill for 3D Drilling Simulation

Directory of Open Access Journals (Sweden)

Buranský Ivan

2016-09-01

Full Text Available The article is focused on optimization of four-facet drill for 3D drilling numerical modelling. For optimization, the process of reverse engineering by PowerShape software was used. The design of four-facet drill was created in NumrotoPlus software. The modified 3D model of the drill was used in the numerical analysis of cutting forces. Verification of the accuracy of 3D models for reverse engineering was implemented using the colour deviation maps. The CAD model was in the STEP format. For simulation software, 3D model in the STEP format is ideal. STEP is a solid model. Simulation software automatically splits the 3D model into finite elements. The STEP model was therefore more suitable than the STL model.

Periodic table of 3d-metal dimers and their ions.

Science.gov (United States)

Gutsev, G L; Mochena, M D; Jena, P; Bauschlicher, C W; Partridge, H

2004-10-08

The ground states of the mixed 3d-metal dimers TiV, TiCr, TiMn, TiFe, TiCo, TiNi, TiCu, TiZn, VCr, VMn, VFe, VCo, VNi, VCu, VZn, CrMn, CrFe, CrCo, CrNi, CrCu, CrZn, MnFe, MnCo, MnNi, MnCu, MnZn, FeCo, FeNi, FeCu, FeZn, CoNi, CoCu, CoZn, NiCu, NiZn, and CuZn along with their singly negatively and positively charged ions are assigned based on the results of computations using density functional theory with generalized gradient approximation for the exchange-correlation functional. Except for TiCo and CrMn, our assignment agrees with experiment. Computed spectroscopic constants (r(e),omega(e),D(o)) are in fair agreement with experiment. The ground-state spin multiplicities of all the ions are found to differ from the spin multiplicities of the corresponding neutral parents by +/-1. Except for TiV, MnFe, and MnCu, the number of unpaired electrons, N, in a neutral ground-state dimer is either N(1)+N(2) or mid R:N(1)-N(2)mid R:, where N(1) and N(2) are the numbers of unpaired 3d electrons in the 3d(n)4s(1) occupation of the constituent atoms. Combining the present and previous results obtained at the same level of theory for homonuclear 3d-metal and ScX (X=Ti-Zn) dimers allows one to construct "periodic" tables of all 3d-metal dimers along with their singly charged ions.

Thick Fe2O3, Fe3O4 films prepared by the chemical solution deposition method

Czech Academy of Sciences Publication Activity Database

Buršík, Josef; Košovan, P.; Šubrt, Jan

2006-01-01

Roč. 39, č. 2 (2006), s. 85-94 ISSN 0928-0707 R&D Projects: GA ČR GA203/01/0408 Institutional research plan: CEZ:AV0Z40320502 Keywords : chemical solution deposition * thick films * alpha-Fe2O3 Subject RIV: CA - Inorganic Chemistry Impact factor: 1.009, year: 2006

Automated assignment and 3D structure calculations using combinations of 2D homonuclear and 3D heteronuclear NOESY spectra

International Nuclear Information System (INIS)

Oezguen, Numan; Adamian, Larisa; Xu Yuan; Rajarathnam, Krishna; Braun, Werner

2002-01-01

The NOAH/DIAMOD suite uses feedback filtering and self-correcting distance geometry to generate 3D structures from unassigned NOESY spectra. In this study we determined the minimum set of experiments needed to generate a high quality structure bundle. Different combinations of 3D 15 N-edited, 13 C-edited HSQC-NOESY and 2D homonuclear 1 H- 1 H NOESY spectra of the 77 amino acid protein, myeloid progenitor inhibitory factor-1 (MPIF-1) were used as input for NOAH/DIAMOD calculations. The quality of the assignments of NOESY cross peaks and the accuracy of the automatically generated 3D structures were compared to those obtained with a conventional manual procedure. Combining data from two types of experiments synergistically increased the number of peaks assigned unambiguously in both individual spectra. As a general trend for the accuracy of the structures we observed structural variations in the backbone fold of the final structures of about 2 A for single spectral data, of 1 A to 1.5 A for double spectral data, and of 0.6 A for triple spectral data sets. The quality of the assignments and 3D structures from the optimal data using all three spectra were similar to those obtained from traditional assignment methods with structural variations within the bundle of 0.6 A and 1.3 A for backbone and heavy atoms, respectively. Almost all constraints (97%) of the automatic NOESY cross peak assignments were cross compatible with the structures from the conventional manual assignment procedure, and an even larger proportion (99%) of the manually derived constraints were compatible with the automatically determined 3D structures. The two mean structures determined by both methods differed only by 1.3 A rmsd for the backbone atoms in the well-defined regions of the protein. Thus NOAD/DIAMOD analysis of spectra from labeled proteins provides a reliable method for high throughput analysis of genomic targets

Differences in 3D vs. 2D analysis in lumbar spinal fusion simulations.

Science.gov (United States)

Hsu, Hung-Wei; Bashkuev, Maxim; Pumberger, Matthias; Schmidt, Hendrik

2018-04-27

Lumbar interbody fusion is currently the gold standard in treating patients with disc degeneration or segmental instability. Despite it having been used for several decades, the non-union rate remains high. A failed fusion is frequently attributed to an inadequate mechanical environment after instrumentation. Finite element (FE) models can provide insights into the mechanics of the fusion process. Previous fusion simulations using FE models showed that the geometries and material of the cage can greatly influence the fusion outcome. However, these studies used axisymmetric models which lacked realistic spinal geometries. Therefore, different modeling approaches were evaluated to understand the bone-formation process. Three FE models of the lumbar motion segment (L4-L5) were developed: 2D, Sym-3D and Nonsym-3D. The fusion process based on existing mechano-regulation algorithms using the FE simulations to evaluate the mechanical environment was then integrated into these models. In addition, the influence of different lordotic angles (5, 10 and 15°) was investigated. The volume of newly formed bone, the axial stiffness of the whole segment and bone distribution inside and surrounding the cage were evaluated. In contrast to the Nonsym-3D, the 2D and Sym-3D models predicted excessive bone formation prior to bridging (peak values with 36 and 9% higher than in equilibrium, respectively). The 3D models predicted a more uniform bone distribution compared to the 2D model. The current results demonstrate the crucial role of the realistic 3D geometry of the lumbar motion segment in predicting bone formation after lumbar spinal fusion. Copyright © 2018 Elsevier Ltd. All rights reserved.

Automated classification of RNA 3D motifs and the RNA 3D Motif Atlas

Science.gov (United States)

Petrov, Anton I.; Zirbel, Craig L.; Leontis, Neocles B.

2013-01-01

The analysis of atomic-resolution RNA three-dimensional (3D) structures reveals that many internal and hairpin loops are modular, recurrent, and structured by conserved non-Watson–Crick base pairs. Structurally similar loops define RNA 3D motifs that are conserved in homologous RNA molecules, but can also occur at nonhomologous sites in diverse RNAs, and which often vary in sequence. To further our understanding of RNA motif structure and sequence variability and to provide a useful resource for structure modeling and prediction, we present a new method for automated classification of internal and hairpin loop RNA 3D motifs and a new online database called the RNA 3D Motif Atlas. To classify the motif instances, a representative set of internal and hairpin loops is automatically extracted from a nonredundant list of RNA-containing PDB files. Their structures are compared geometrically, all-against-all, using the FR3D program suite. The loops are clustered into motif groups, taking into account geometric similarity and structural annotations and making allowance for a variable number of bulged bases. The automated procedure that we have implemented identifies all hairpin and internal loop motifs previously described in the literature. All motif instances and motif groups are assigned unique and stable identifiers and are made available in the RNA 3D Motif Atlas (http://rna.bgsu.edu/motifs), which is automatically updated every four weeks. The RNA 3D Motif Atlas provides an interactive user interface for exploring motif diversity and tools for programmatic data access. PMID:23970545

Fe2O3/Reduced Graphene Oxide/Fe3O4 Composite in Situ Grown on Fe Foil for High-Performance Supercapacitors.

Science.gov (United States)

Zhao, Chongjun; Shao, Xiaoxiao; Zhang, Yuxiao; Qian, Xiuzhen

2016-11-09

A Fe 2 O 3 /reduced graphene oxide (RGO)/Fe 3 O 4 nanocomposite in situ grown on Fe foil was synthesized via a simple one-step hydrothermal growth process, where the iron foil served as support, reductant of graphene oxide, Fe source of Fe 3 O 4 , and also the current collector of the electrode. When it directly acted as the electrode of a supercapacitor, as-synthesized Fe 2 O 3 /RGO/Fe 3 O 4 @Fe exhibited excellent electrochemical performance with a high capability of 337.5 mF/cm 2 at 20 mA/cm 2 and a superior cyclability with 2.3% capacity loss from the 600th to the 2000th cycle.

Ground and excited states of the [Fe(H2O)6]2+ and [Fe(H2O)6]3+ clusters: Insight into the electronic structure of the [Fe(H2O)6]2+ – [Fe(H2O)6]3+ complex

Energy Technology Data Exchange (ETDEWEB)

Miliordos, Evangelos; Xantheas, Sotiris S.

2015-04-14

We report the ground and low lying electronically excited states of the [Fe(H2O)6]2+ and [Fe(H2O)6]3+ clusters using multi-configuration electronic structure theory. In particular, we have constructed the Potential Energy Curves (PECs) with respect to the iron-oxygen distance when removing all water ligands at the same time from the cluster minima and established their correlation to the long range dissociation channels. Due to the fact that both the second and third ionization potentials of iron are larger than the one for water, the ground state products asymptotically correlate with dissociation channels that are repulsive in nature at large separations as they contain at least one H2O+ fragment and a positive metal center. The most stable equilibrium structures emanate – via intersections and/or avoided crossings – from the channels consisting of the lowest electronic states of Fe2+(5D; 3d6) or Fe3+(6S; 3d5) and six neutral water molecules. Upon hydration, the ground state of Fe2+(H2O)6 is a triply (5Tg) degenerate one with the doubly (5Eg) degenerate state lying slightly higher in energy. Similarly, Fe3+(H2O)6 has a ground state of 6Ag symmetry under Th symmetry. We furthermore examine a multitude of electronically excited states of many possible spin multiplicities, and report the optimized geometries for several selected states. The PECs for those cases are characterized by a high density of states. Focusing on the ground and the first few excited states of the [Fe(H2O)6]2+ and [Fe(H2O)6]3+ clusters, we studied their mutual interaction in the gas phase. We obtained the optimal geometries of the Fe2+(H2O)6 – Fe3+(H2O)6 gas phase complex for different Fe–Fe distances. For distances shorter than 6.0 Å, the water molecules in the respective first solvation shells located between the two metal centers were found to interact via weak hydrogen bonds. We examined a total of ten electronic states for this complex, including those corresponding to the

Study of U - Pu - Fe alloys (Masurca critical experiment); Etudes d'alliages U-Pu-Fe (experience critique MASURCA)

Energy Technology Data Exchange (ETDEWEB)

Barthelemy, P; Boucher, R [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1965-07-01

pour ces deux dernieres teneurs le passage du point de transformation (595 et 590 deg. C respectivement) entraine une deterioration rapide et complete des echantillons sous air. Les essais d'inflammabilite sous air montrent que la temperature de debut d'oxydation se situe vers 250 deg. C et que la reaction ne s'entretient pas d'elle-meme. On n'a pas observe d'inflammation proprement dite lors d'une montee jusqu'a 660 deg. C. L'etude dilatometrique a permis de determiner la temperature de transformation a l'etat solide, la temperature de fusion commencante et les coefficients de dilatation. En dessous de la transformation les alliages sont formes principalement des phases U-Pu zeta et (U, Pu){sub 6}Fe. La conductibilite thermique, le module d'Young, la densite et la chaleur de fusion ont ete mesures. les essais de compatibilite U-Pu-Fe{approx}acier inox NS 22 S montrent qu'au contact des deux alliages se forme une phase du type (U,Pu){sub 6}Fe. L'alliage a 1% de fer parait preferable, la phase (U,Pu){sub 6}Fe formee a l'interface etant 2 a 3 fois moins etendue qu'avec l'alliage a 1,5% de fer. Enfin le probleme de la stabilite thermique a temperature peu elevee a ete considere pour l'alliage a 1% de fer. Le passage du point de transformation a 595 deg. C entraine l'apparition d'une anomalie dilatometrique, au refroidissement, se traduisant par une tres faible dilatation dont l'amplitude diminue en fonction du nombre de cycles effectues entre 20 et 650 deg. C sur l'alliage brut de coulee a l'origine. Par contre, des cyclages thermiques entre 50 et 400 deg. C montrent que les alliages ne presentent pas d'anomalie et sont stables. De meme, des maintiens de 5 mois a 100 deg. C, 200 deg. C, 300 deg. C, sous vide, n'entrainent aucune alteration des alliages. (auteurs)

Identification of the transition arrays 3d74s-3d74p in Br X and 3d64s-3d64p in Br XI

International Nuclear Information System (INIS)

Zeng, X.T.; Jupen, C.; Bengtsson, P.; Engstroem, L.; Westerlind, M.; Martinson, I.

1991-01-01

We report a beam-foil study of multiply ionized bromine in the region 400-1300A, performed with 6 and 8 MeV Br ions from a tandem accelerator. At these energies transitions belonging to Fe-like Br X and Mn-like Br XI are expected to be prominent. We have identified 31 lines as 3d 7 4s-3d 7 4p transitions in Br X, from which 16 levels of the previously unknown 3d 7 4s configuration could be established. We have also added 6 new 3d 7 4p levels to the 99 previously known. For Br XI we have classified 9 lines as 3d 6 4s-3d 6 4p combinations. The line identifications have been corroborated by isoelectronic comparisons and theoretical calculations using the superposition-of-configurations technique. (orig.)

Molecular orbital (SCF-X-α-SW) theory of Fe2+-Mn3+, Fe3+-Mn2+, and Fe3+-Mn3+ charge transfer and magnetic exchange in oxides and silicates

Science.gov (United States)

Sherman, David M.

1990-01-01

Metal-metal charge-transfer and magnetic exchange interactions have important effects on the optical spectra, crystal chemistry, and physics of minerals. Previous molecular orbital calculations have provided insight on the nature of Fe2+-Fe3+ and Fe2+-Ti4+ charge-transfer transitions in oxides and silicates. In this work, spin-unrestricted molecular orbital calculations on (FeMnO10) clusters are used to study the nature of magnetic exchange and electron delocalization (charge transfer) associated with Fe3+-Mn2+, Fe3+-Mn3+, and Fe2+-Mn3+ interactions in oxides and silicates. 

Intensity ratio among Ne-like FeXVII n=3-2 transitions

International Nuclear Information System (INIS)

Morita, Shigeru; Oishi, Tetsutarou; Murakami, Izumi; Goto, Motoshi; Huang, Xianli; Zhang, Hongming

2016-01-01

Radial profiles of FeXVII 3s-2p and 3d-2p transitions emitted in wavelength range of 15-17A have been observed in Large Helical Device (LHD). The Chord-integrated radial profiles are converted into radial emissivity profile by means of Abel inversion. The emissivity ratios among FeXVII n=3-2 transitions calculated from the radial emissivity profile are compared with calculation based on a collisional-radiative (CR) model developed for Fe ions. The result reasonably confirms the effect of electron temperature and density on the emissivity ratios. However, the emissivity of 3C (2p"53d "1P_1 → 2p"6) transition is obviously lower than the prediction from the CR model. This discrepancy is consistent with measurements in the solar corona and other laboratory plasmas. (author)

Interface magnetism of 3d transition metals

DEFF Research Database (Denmark)

Niklasson, A. M. N.; Johansson, B.; Skriver, Hans Lomholt

1999-01-01

The layered resolved magnetic spin moments of the magnetic 3d bilayer interfaces Fe/V bcc, Fe/Co bcc, Fe/Cu bcc, Co/V bcc, Co/Ni fee, Co/Cu fee, Ni/V fee, Ni/Cr fcc, Ni/Cu fee and the magnetic surfaces Fe bcc, Co bcc, Co fee, and Ni fee are calculated for the (001), (011), and (111) orientations...

Structure and magnetic properties of the 3d transition-metal mono-borides TM–B (TM=Mn, Fe, Co) under pressures

International Nuclear Information System (INIS)

Bourourou, Y.; Beldi, L.; Bentria, B.; Gueddouh, A.; Bouhafs, B.

2014-01-01

In this paper, spin-polarization and pressure effects on the structural and electronic properties of the 3d transition-metal mono-borides TM–B (TM=Mn, Fe, Co) have been studied by using both local spin-density approximation (LSDA) and generalized gradient approximation (GGA) within the framework of density-functional theory (DFT). At equilibrium, spin-polarization calculations show that MnB and FeB compounds carry magnetic moment. The non-spin-polarization results show that the non-magnetic state is unstable for MnB and FeB compounds, but a stable non-magnetic phase for CoB compound, which is discussed in the framework of the well-known Stoner criterion. The calculated lattice parameters, bulk moduli, their first-pressure derivatives and magnetic moments agree well with experimental and other theoretical results. Significant differences in volume and in bulk modulus were found between the magnetic and non-magnetic case reached 4%, 22%, respectively. The effect of pressure on the crystal structure reflects in a compression of the unit cell volume with a decreasing in the magnetic moment. The density of states of MnB and FeB ferromagnetic compounds are significantly modified under high pressures. The exchange energy decreases with increasing pressure, at approximately V/V 0 =0.6, the exchange energy becomes absent in ferromagnetic compounds causes mirror in upper and lowers half panels. Finally, we notice that spin-polarization and pressure play a crucially important role in determining the electronic and structural properties of 3d transition-metal mono-borides. - Highlights: • Spin polarization and pressure effects on TM–B (TM=Mn, Fe, Co) have been investigated. • The non-spin-polarization results show that the non-magnetic state is stable for CoB. • The magnetic states of MnB and FeB are found more stable than their nonmagnetic states. • We report significant differences between the magnetic and non-magnetic cases. • The density of states of MnB and

Design and syntheses of hybrid metal-organic materials based on K3[M(C2O4)3]·3H2O [M(III)=Fe, Al, Cr] metallotectons

Science.gov (United States)

Sun, Yayong; Zong, Yingxia; Ma, Haoran; Zhang, Ao; Liu, Kang; Wang, Debao; Wang, Wenqiang; Wang, Lei

2016-05-01

By using K3[M(C2O4)3]·3H2O [M(III)=Fe, Al, Cr] (C2O42-=oxalate) metallotectons as the starting material, we have synthesized eight novel complexes with formulas [{Fe(C2O4)2(H2O)2}2]·(H-L1)2·H2O 1, [Fe(C2O4)Cl2]·(H2-L2)0.5·(L2)0.5·H2O 2, [{Fe(C2O4)1.5Cl2}2]·(H-L3)43, [Fe2(C2O4)Cl8]·(H2-L4)2·2H2O 4, K[Al(C2O4)3]·(H2-L5)·2H2O 5, K[Al(C2O4)3]·(H-L6)2·2H2O 6, K[Cr(C2O4)3]·2H2O 7, Na[Fe(C2O4)3]·(H-L6)2·2H2O 8 (with L1=4-dimethylaminopyridine, L2=2,3,5,6-tetramethylpyrazine, L3=2-aminobenzimidazole, L4=1,4-bis-(1H-imidazol-1-yl)benzene, L5=1,4-bis((2-methylimidazol-1-yl)methyl)benzene, L6=2-methylbenzimidazole). Their structures have been determined by single-crystal X-ray diffraction analyses, elemental analyses, IR spectra and thermogravimetric analyses. Compound 3 is a 2D H-bonded supramolecular architecture. Others are 3D supramolecular structures. Compound 1 shows a [Fe(C2O4)2(H2O)2]- unit and 3D antionic H-bonded framework. Compound 2 features a [Fe(C2O4)Cl2]- anion and 1D iron-oxalate-iron chain. Compound 3 features a [Fe2(C2O4)3Cl4]4- unit. Compound 4 features distinct [Fe2(C2O4)Cl8]4- units, which are mutual linked by water molecules to generated a 2D H-bonded network. Compound 5 features infinite ladder-like chains constructed by [Al(C2O4)3]3- units and K+ cations. The 1D chains are further extended into 3D antionic H-bonded framework through O-H···O H-bonds. Compounds 6-8 show 2D [KAl(C2O4)3]2- layer, [KCr(C2O4)3]2- layer and [NaFe(C2O4)3]2- layer, respectively.

Study of the (3He,d) reactions on 58Ni, 60Ni and 56Fe near the Coulomb barrier

International Nuclear Information System (INIS)

Baghdadi, A.; Seltz, R.; Magnac-Valette, D.; Bonneaud, G.; Gerardin, C.

1975-01-01

Using spectroscopic information gained by earlier measurements of the proton bound states populated by stripping reactions, ( 3 He,d) reactions on 58 Ni, 60 Ni and 56 Fe targets are studied at energies near the Coulomb barrier and evaluation is made of the vertex function 3 He>. This value is then used to determine spectroscopic factors for low-lying states in 57 Co [fr

Illustrating the disassembly of 3D models

KAUST Repository

Guo, Jianwei; Yan, Dongming; Li, Er; Dong, Weiming; Wonka, Peter; Zhang, Xiaopeng

2013-01-01

We present a framework for the automatic disassembly of 3D man-made models and the illustration of the disassembly process. Given an assembled 3D model, we first analyze the individual parts using sharp edge loops and extract the contact faces

A note on structural and dielectric properties of BiFeO3- PbTiO3 and BiFeO3- PbZrO3 composites

International Nuclear Information System (INIS)

Satpathy, S. K.; Mohanty, N. K.; Behera, A. K.; Behera, B.; Nayak, P.

2015-01-01

The composites of BiFeO 3 -PbTiO 3 (BF-PT) and BiFeO 3 -PbZrO 3 (BF-PZ) were prepared by mixed oxide method. Room temperature X-ray diffraction data confirms the rhombohedral and tetragonal crystal structure respectively. Dielectric constant of BF-PZ is found to give high value compared to BF-PT and hence, there is an increase value of ac conductivity for the former. Both the composites show negative temperature coefficient of resistance (NTCR) behavior. The activation energies of BF-PT and BF-PZ are found to be 0.35 eV and 0.53 eV respectively. The d 33 coefficients are found to be 2.0 and 2.1 pC/N for BF-PT and BF-PZ respectively

3D images and expert system

International Nuclear Information System (INIS)

Hasegawa, Jun-ichi

1998-01-01

This paper presents an expert system called 3D-IMPRESS for supporting applications of three dimensional (3D) image processing. This system can automatically construct a 3D image processing procedure based on a pictorial example of the goal given by a user. In the paper, to evaluate the performance of the system, it was applied to construction of procedures for extracting specific component figures from practical chest X-ray CT images. (author)

Enhanced saturation magnetization of Fe3Si nanodot-embedded Fe80Si17Nb3 flexible film for efficient wireless power transfer

International Nuclear Information System (INIS)

Pai, Yi-Hao; Yan, Zih-Yu; Fu, Ping-Hao

2013-01-01

An efficient magnetically coupled resonance response is performed using an iron silicide-based nanostructured magnetoelectric material with high saturation magnetization for the wireless charging of battery-powered consumer electronics. With 500 °C annealing, the self-assembled Fe 3 Si nanodots buried in the Fe 80 Si 17 Nb 3 host matrix with (220) lattice spacing of 1.99 Å corresponding to a volume density of 8.96 × 10 16 cm 3 , can be obtained and a maximum saturation magnetization of 244 emu g −1 achieved. The return loss of the antenna will be tuned to match the designed frequency with greater attenuated intensity (−0.39 dB) and a relatively narrow bandwidth (6 kHz) when the Fe 3 Si nanodot-embedded Fe 80 Si 17 Nb 3 sample is placed in a WiTricity system. An efficient wireless power transfer can be created and improved from 47.5% to 97.3%. The associated coil and loop antenna resonators are significantly readjusted to match the power transfer by putting this nanostructured magnetoelectric material in a WiTricity system. - Highlights: • The saturation magnetization is effective enhancement in the presence of Fe 3 Si nanodot buried in the Fe 80 Si 17 Nb 3 . • A saturation magnetization of 244 emu g −1 is proposed for high-efficiency wireless power transfer. • The return loss of the antenna will be tuned to match the designed frequency. • Such a wireless power transfer can be enhanced efficiency up to 97.3%

Epitaxial Fe3Si/Ge/Fe3Si thin film multilayers grown on GaAs(001)

International Nuclear Information System (INIS)

Jenichen, B.; Herfort, J.; Jahn, U.; Trampert, A.; Riechert, H.

2014-01-01

We demonstrate Fe 3 Si/Ge/Fe 3 Si/GaAs(001) structures grown by molecular-beam epitaxy and characterized by transmission electron microscopy, electron backscattered diffraction, and X-ray diffraction. The bottom Fe 3 Si epitaxial film on GaAs is always single crystalline. The structural properties of the Ge film and the top Fe 3 Si layer depend on the substrate temperature during Ge deposition. Different orientation distributions of the grains in the Ge and the upper Fe 3 Si film were found. The low substrate temperature T s of 150 °C during Ge deposition ensures sharp interfaces, however, results in predominantly amorphous films. We find that the intermediate T s (225 °C) leads to a largely [111] oriented upper Fe 3 Si layer and polycrystal films. The high T s of 325 °C stabilizes the [001] oriented epitaxial layer structure, i.e., delivers smooth interfaces and single crystal films over as much as 80% of the surface area. - Highlights: • Fe 3 Si/Ge/Fe 3 Si/GaAs(001) structures are grown by MBE. • The bottom Fe 3 Si film is always single crystalline. • The properties of the Ge film depend on the substrate temperature during deposition. • Optimum growth conditions lead to almost perfect epitaxy of Ge on Fe 3 Si

3D automatic exposure control for 64-detector row CT: Radiation dose reduction in chest phantom study

Energy Technology Data Exchange (ETDEWEB)

Matsumoto, Keiko, E-mail: palm_kei@yahoo.co.jp [Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan); Department of Radiology, Yamanashi University, Shimokato, Yamanashi (Japan); Ohno, Yoshiharu; Koyama, Hisanobu; Kono, Atsushi [Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan); Inokawa, Hiroyasu [Toshiba Medical Systems, Ohtawara, Tochigi (Japan); Onishi, Yumiko [Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan); Nogami, Munenobu [Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan); Division of Image-Based Medicine, Institute of Biomedical Research and Innovation, Kobe, Hyogo (Japan); Takenaka, Daisuke [Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan); Araki, Tsutomu [Department of Radiology, Yamanashi University, Shimokato, Yamanashi (Japan); Sugimura, Kazuro [Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan)

2011-03-15

Purpose: The purpose of this study was to determine the utility of three-dimensional (3D) automatic exposure control (AEC) for low-dose CT examination in a chest phantom study. Materials and methods: A chest CT phantom including simulated focal ground-glass opacities (GGOs) and nodules was scanned with a 64-detector row CT with and without AEC. Performance of 3D AEC included changing targeted standard deviations (SDs) of image noise from scout view. To determine the appropriate targeted SD number for identification, the capability of overall identification with the CT protocol adapted to each of the targeted SDs was compared with that obtained with CT without AEC by means of receiver operating characteristic analysis. Results: When targeted SD values equal to or higher than 250 were used, areas under the curve (Azs) of nodule identification with CT protocol using AEC were significantly smaller than that for CT protocol without AEC (p < 0.05). When targeted SD numbers at equal to or more than 180 were adapted, Azs of CT protocol with AEC had significantly smaller than that without AEC (p < 0.05). Conclusion: This phantom study shows 3D AEC is useful for low-dose lung CT examination, and can reduce the radiation dose while maintaining good identification capability and good image quality.

Magnetism on quasi-1-D lattices in novel non-centrosymmetric Ba{sub 3}CrVS{sub 4}O{sub 3} and in centrosymmetric La{sub 3}TMWS{sub 3}O{sub 6} (TM = Cr, Fe, Co)

Energy Technology Data Exchange (ETDEWEB)

Kim, Jinkwang; Lai, Kwing To; Valldor, Martin, E-mail: martin.valldor@cpfs.mpg.de

2017-08-01

Highlights: • Quasi 1-D chains of magnetic ions exist in Ba{sub 3}CrVS{sub 4}O{sub 3} and La{sub 3}TMWS{sub 3}O{sub 6} (TM = Cr, Fe, Co). • The magnetism of non-centrosymmetric Ba{sub 3}CrVS{sub 4}O{sub 3} is different from centrosymmetric La{sub 3}CrWS{sub 3}O{sub 6}. • Several intrinsic magnetic anomalies are observed without long-ranged spin orderings. - Abstract: La{sub 3}TMWS{sub 3}O{sub 6} (TM = Fe, Co) and novel Ba{sub 3}CrVS{sub 4}O{sub 3} can be obtained as pure polycrystalline samples by mineralizer aided solid-state reactions and a solid-state reaction with further purification by water, respectively. In contrast, La{sub 3}CrWS{sub 3}O{sub 6} needs a standard solid-state reaction to form but the final product contains observable impurities. All four compounds contain similar quasi-1-D magnetic lattices although La-based ones are centrosymmetric (P6{sub 3}/m) and the Ba-containing one is polar and non-centrosymmetric (P6{sub 3}). Strong antiferromagnetic couplings are observed along the magnetic chains in the Fe and Cr containing compounds. As a result, short-range magnetic order is suggested at low temperatures for the Fe-chain, which can be related to magneto-electric couplings. The Co{sup 3+}-homologue shows typical diamagnetic behavior, as supported by its insulating nature, which is due to a low-spin state. The polar Cr{sup 3+}-compound exhibits very different magnetic behavior compared to its corresponding non-polar relative. This proves a strong influence on the physical properties from the crystallographic symmetry.

Electrical conduction of glasses in the system Fe2O3-Sb2O3-TeO2; Fe2O3-Sb2O3-TeO2 kei garasu no denki dendo

Energy Technology Data Exchange (ETDEWEB)

Qiu, Honghua; Mori, H; Sakata, H; Hirayama, T [Tokai Univ., Tokyo (Japan). Faculty of Engineering

1995-01-01

In this study, taking into consideration that TeO2 is a component of the glass network and Sb2O3 shows the redox effect in the glasses reducing its possibility of transformation of Sb{sup 3+} to Sb{sup 5+} as well as glass basicity, highly conductive tellurite based glasses have been prepared by the press-quenching method selecting the Fe2O3-Sb2O3-TeO2 system, and the electroconductive mechanism of the glasses has been examined by measuring its D.C. conductivity {sigma}. Part of the obtained information is as follows; the glass formation range of the Fe2O3-Sb2O3-TeO2 system has been 0 {le} Fe2O3 {le} 15mol%, 0 {le} Sb2O3 {le} 18mol% and 78 {le} TeO2 {le} 100mol% and about 15mol% of the additional amount of Fe2O3 has been the limit of glass formation. As the amount of Fe2O3 has increased, C{sub Fe} has also increased and with this, the linear electroconductivity of the glasses has increased from 1.86 {times} 10{sup -7}S{center_dot}cm{sup -1} to 1.62 {times} 10{sup -6}S{center_dot}cm{sup -1} and the glasses have been confirmed as the n-type semiconductor. The factor determining {sigma} of the glasses has been C{sub Fe} which has increased as the amount of Fe2O3 has increased. 34 refs., 8 figs., 2 tabs.

Comparison of Ab initio low-energy models for LaFePO, LaFeAsO, BaFe2As2, LiFeAs, FeSe, and FeTe. Electron correlation and covalency

International Nuclear Information System (INIS)

Miyake, Takashi; Nakamura, Kazuma; Arita, Ryotaro; Imada, Masatoshi

2010-01-01

Effective low-energy Hamiltonians for several different families of iron-based superconductors are compared after deriving them from the downfolding scheme based on first-principles calculations. Systematic dependences of the derived model parameters on the families are elucidated, many of which are understood from the systematic variation of the covalency between Fe-3d and pnictogen-/chalcogen-p orbitals. First, LaFePO, LaFeAsO (1111), BaFe 2 As 2 (122), LiFeAs (111), FeSe, and FeTe (11) have overall similar band structures near the Fermi level, where the total widths of 10-fold Fe-3d bands are mostly around 4.5 eV. However, the derived effective models of the 10-fold Fe-3d bands (d model) for FeSe and FeTe have substantially larger effective onsite Coulomb interactions U - 4.2 and 3.4 eV, respectively, after the screening by electrons on other bands and after averaging over orbitals, as compared to ∼2.5 eV for LaFeAsO. The difference is similar in the effective models containing p orbitals of As, Se or Te (dp or dpp model), where U ranges from ∼4 eV for the 1111 family to ∼7 eV for the 11 family. The exchange interaction J has a similar tendency. The family dependence of models indicates a wide variation ranging from weak correlation regime (LaFePO) to substantially strong correlation regime (FeSe). The origin of the larger effective interaction in the 11 family is ascribed to smaller spread of the Wannier orbitals generating larger bare interaction, and to fewer screening channels by the other bands. This variation is primarily derived from the distance h between the pnictogen/chalcogen position and the Fe layer: The longer h for the 11 family generates more ionic character of the bonding between iron and anion atoms, while the shorter h for the 1111 family leads to more covalent-bonding character, the larger spread of the Wannier orbitals, and more efficient screening by the anion p orbitals. The screened interaction of the d model is strongly orbital

Acetone sensors based on microsheet-assembled hierarchical Fe2O3 with different Fe3+ concentrations

Science.gov (United States)

Wang, Han; Yan, Lei; Li, Shuo; Li, Yu; Liu, Li; Du, Liting; Duan, Haojie; Cheng, Yali

2018-02-01

Several different morphologies of microsheet-assembled Fe2O3 have been fabricated by hydrothermal method using diverse concentrations of Fe3+ precursor solutions (0.025, 0.020, 0.015, 0.010 mol/L Fe3+). The as-synthesized materials have been characterized by scanning electron microscope (SEM), X-ray powder diffraction (XRD), and energy-dispersive X-ray spectrometry (EDS). The SEM images reflect that the morphologies of as-synthesized materials are affected by the concentrations of Fe3+ in precursor solutions. The less concentration of Fe3+, the more porous of Fe2O3 microflowers, and thinner of slices distributed on the surface. Furthermore, gas sensors based on these Fe2O3 microflowers manufactured and tested to various common gases. The optimum response value to 100 ppm acetone is 52 at the working temperature of 220 °C. Meanwhile, the Fe2O3 microflower sensors possess ultrafast response-recovery speed, which are 8 and 19 s, respectively. The possible sensing mechanism was mainly attributed to the high surface area, three-dimensional porous structure.

Magnetization reversal and coercivity of Fe3Se4 nanowire arrays

Science.gov (United States)

Li, D.; Li, S. J.; Zhou, Y. T.; Bai, Y.; Zhu, Y. L.; Ren, W. J.; Long, G.; Zeng, H.; Zhang, Z. D.

2015-05-01

The microstructure and magnetic properties of Fe3Se4 nanowire (NW) arrays in anodic aluminum oxide (AAO) porous membrane are studied. Cross-sectional SEM and plane-view TEM images show that the mean wire diameter (dw) and the center-to-center spacing (D) of Fe3Se4 nanowires are about 220 nm and 330 nm, respectively. The field-cooled magnetization dependent on the temperature indicates a Curie temperature around 334 K for the Fe3Se4 nanowires. The coercivities of Fe3Se4 nanowires at 10 K, obtained from the in-plane and out-of-plane hysteresis loops, are as high as 22.4 kOe and 23.3 kOe, which can be understood from the magnetocrystalline anisotropy and the magnetization reversal process.

Microstructure and Properties of Fe3Al-Fe3AlC x Composite Prepared by Reactive Liquid Processing

Science.gov (United States)

Verona, Maria Nalu; Setti, Dalmarino; Paredes, Ramón Sigifredo Cortés

2018-04-01

A Fe3Al-Fe3AlC x composite was prepared using reactive liquid processing (RLP) through controlled mixture of carbon steel and aluminum in the liquid state. The microstructure and phases of the composite were assessed using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, optical microscopy, and differential scanning calorimetry. In addition, the density, hardness, microhardness, and elastic modulus were evaluated. The Fe3Al-Fe3AlC x composite consisted of 65 vol pct Fe3Al and 35 vol pct Fe3AlC x ( κ). The κ phase contained 10.62 at. pct C, resulting in the stoichiometry Fe3AlC0.475. The elastic modulus of the Fe3Al-Fe3AlC0.475 composite followed the rule of mixtures. The RLP technique was shown to be capable of producing Fe3Al-Fe3AlC0.475 with a microstructure and properties similar to those achieved using other processing techniques reported in the literature.

Influence of ruthenium ions on the precipitation of α-FeOOH, α-Fe2O3 and Fe3O4 in highly alkaline media

International Nuclear Information System (INIS)

Krehula, Stjepko; Music, Svetozar

2006-01-01

The influence of ruthenium ions on the precipitation of goethite (α-FeOOH), α-Fe 2 O 3 and Fe 3 O 4 in highly alkaline media was investigated by 57 Fe Moessbauer and FT-IR spectroscopies, thermal field emission scanning electron microscope (FE SEM) and EDS. The presence of Ru-dopant strongly affected the precipitation of α-FeOOH at highly alkaline pH, i.e. the formation of α-Fe 2 O 3 was also noticed. A decrease of hyperfine magnetic field (HMF) at RT from 35.1 T (undoped α-FeOOH) to 31.3 T for sample with [Ru]/([Ru] + [Fe]) = 0.0196 was assigned to the incorporation of ruthenium ions into the α-FeOOH structure. Moessbauer spectroscopy showed the formation of stoichiometric Fe 3 O 4 for [Ru]/([Ru] + [Fe]) = 0.0291-0.0909. α-Fe 2 O 3 and Fe 3 O 4 did not show a tendency to the formation of solid solutions with ruthenium ions. FE SEM observations of the samples showed that reference α-FeOOH sample contained acicular particles of good uniformity, which increased the length up to ∼5 times with increase of concentration of ruthenium ions. On the other hand, large octahedral Fe 3 O 4 crystals (particles) were associated with small particles of ruthenium (hydrous) oxide with a size in the range ∼100 nm or less. A possible catalytic action of ruthenium that created reduction conditions for Fe 3+ ions and formation of Fe 2+ ions for precipitation of Fe 3 O 4 was discussed

Fabrication and Characterization of 3D-Printed Highly-Porous 3D LiFePO₄ Electrodes by Low Temperature Direct Writing Process.

Science.gov (United States)

Liu, Changyong; Cheng, Xingxing; Li, Bohan; Chen, Zhangwei; Mi, Shengli; Lao, Changshi

2017-08-10

LiFePO₄ (LFP) is a promising cathode material for lithium-ion batteries. In this study, low temperature direct writing (LTDW)-based 3D printing was used to fabricate three-dimensional (3D) LFP electrodes for the first time. LFP inks were deposited into a low temperature chamber and solidified to maintain the shape and mechanical integrity of the printed features. The printed LFP electrodes were then freeze-dried to remove the solvents so that highly-porous architectures in the electrodes were obtained. LFP inks capable of freezing at low temperature was developed by adding 1,4 dioxane as a freezing agent. The rheological behavior of the prepared LFP inks was measured and appropriate compositions and ratios were selected. A LTDW machine was developed to print the electrodes. The printing parameters were optimized and the printing accuracy was characterized. Results showed that LTDW can effectively maintain the shape and mechanical integrity during the printing process. The microstructure, pore size and distribution of the printed LFP electrodes was characterized. In comparison with conventional room temperature direct ink writing process, improved pore volume and porosity can be obtained using the LTDW process. The electrochemical performance of LTDW-fabricated LFP electrodes and conventional roller-coated electrodes were conducted and compared. Results showed that the porous structure that existed in the printed electrodes can greatly improve the rate performance of LFP electrodes.

3-D laser confocal microscopy study of the oxidation of NdFeB magnets in atmospheric conditions

Science.gov (United States)

Meakin, J. P.; Speight, J. D.; Sheridan, R. S.; Bradshaw, A.; Harris, I. R.; Williams, A. J.; Walton, A.

2016-08-01

Neodymium iron boron (NdFeB) magnets are used in a number of important applications, such as generators in gearless wind turbines, motors in electric vehicles and electronic goods (e.g.- computer hard disk drives, HDD). Hydrogen can be used as a processing gas to separate and recycle scrap sintered Nd-Fe-B magnets from end-of-life products to form a powder suitable for recycling. However, the magnets are likely to have been exposed to atmospheric conditions prior to processing, and any oxidation could lead to activation problems for the hydrogen decrepitation reaction. Many previous studies on the oxidation of NdFeB magnets have been performed at elevated temperatures; however, few studies have been formed under atmospheric conditions. In this paper a combination of 3-D laser confocal microscopy and Raman spectroscopy have been used to assess the composition, morphology and rate of oxidation/corrosion on scrap sintered NdFeB magnets. Confocal microscopy has been employed to measure the growth of surface reaction products at room temperature, immediately after exposure to air. The results showed that there was a significant height increase at the triple junctions of the Nd-rich grain boundaries. Using Raman spectroscopy, the product was shown to consist of Nd2O3 and formed only on the Nd-rich triple junctions. The diffusion coefficient of the triple junction reaction product growth at 20 °C was determined to be approximately 4 × 10-13 cm2/sec. This value is several orders of magnitude larger than values derived from the diffusion controlled oxide growth observations at elevated temperatures in the literature. This indicates that the growth of the room temperature oxidation products are likely defect enhanced processes at the NdFeB triple junctions.

Automatic measurement of cusps in 2.5D dental images

Science.gov (United States)

Wolf, Mattias; Paulus, Dietrich W.; Niemann, Heinrich

1996-01-01

Automatic reconstruction of occlusal surfaces of teeth is an application which might become more and more urgent due to the toxicity of amalgam. Modern dental chairside equipment is currently restricted to the production of inlays. The automatic reconstruction of the occlusal surface is presently not possible. For manufacturing an occlusal surface it is required to extract features from which it is possible to reconstruct destroyed teeth. In this paper, we demonstrate how intact upper molars can be automatically extracted in dental range and intensity images. After normalization of the 3D location, the sizes of the cusps are detected and the distances between them are calculated. In the presented approach, the detection of the upper molar is based on a knowledge-based segmentation which includes anatomic knowledge. After the segmentation of the interesting tooth the central fossa is calculated. The normalization of the spatial location is archieved by aligning the detected fossa with a reference axis. After searching the cusp tips in the range image the image is resized. The methods have been successfully tested on 60 images. The results have been compared with the results of a dentist's evaluation on a sample of 20 images. The results will be further used for automatic production of tooth inlays.

Automatic reconstruction of 3D urban landscape by computing connected regions and assigning them an average altitude from LiDAR point cloud image

Science.gov (United States)

Kawata, Yoshiyuki; Koizumi, Kohei

2014-10-01

The demand of 3D city modeling has been increasing in many applications such as urban planing, computer gaming with realistic city environment, car navigation system with showing 3D city map, virtual city tourism inviting future visitors to a virtual city walkthrough and others. We proposed a simple method for reconstructing a 3D urban landscape from airborne LiDAR point cloud data. The automatic reconstruction method of a 3D urban landscape was implemented by the integration of all connected regions, which were extracted and extruded from the altitude mask images. These mask images were generated from the gray scale LiDAR image by the altitude threshold ranges. In this study we demonstrated successfully in the case of Kanazawa city center scene by applying the proposed method to the airborne LiDAR point cloud data.

Removal of FePO4 and Fe3(PO4)2 crystals on the surface of passive fillers in Fe0/GAC reactor using the acclimated bacteria

International Nuclear Information System (INIS)

Lai, Bo; Zhou, Yuexi; Yang, Ping; Wang, Juling; Yang, Jinghui; Li, Huiqiang

2012-01-01

Highlights: ► Fe 3 (PO 4 ) 2 and FePO 4 crystals would weaken treatment efficiency of Fe 0 /GAC reactor. ► Fe 3 (PO 4 ) 2 and FePO 4 crystals could be removed by the acclimated bacteria. ► FeS and sulfur in the passive film would be removed by the sulfur-oxidizing bacteria. ► Develop a cost-effective bio-regeneration technology for the passive fillers. - Abstract: As past studies presented, there is obvious defect that the fillers in the Fe 0 /GAC reactor begin to be passive after about 60 d continuous running, although the complicated, toxic and refractory ABS resin wastewater can be pretreated efficiently by the Fe 0 /GAC reactor. During the process, the Fe 3 (PO 4 ) 2 and FePO 4 crystals with high density in the passive film are formed by the reaction between PO 4 3− and Fe 2+ /Fe 3+ . Meanwhile, they obstruct the formation of macroscopic galvanic cells between Fe 0 and GAC, which will lower the wastewater treatment efficiency of Fe 0 /GAC reactor. In this study, in order to remove the Fe 3 (PO 4 ) 2 and FePO 4 crystals on the surface of the passive fillers, the bacteria were acclimated in the passive Fe 0 /GAC reactor. According to the results, it can be concluded that the Fe 3 (PO 4 ) 2 and FePO 4 crystals with high density in the passive film could be decomposed or removed by the joint action between the typical propionic acid type fermentation bacteria and sulfate reducing bacteria (SRB), whereas the PO 4 3− ions from the decomposition of the Fe 3 (PO 4 ) 2 and FePO 4 crystals were released into aqueous solution which would be discharged from the passive Fe 0 /GAC reactor. Furthermore, the remained FeS and sulfur (S) in the passive film also can be decomposed or removed easily by the oxidation of the sulfur-oxidizing bacteria. This study provides some theoretical references for the further study of a cost-effective bio-regeneration technology to solve the passive problems of the fillers in the zero-valent iron (ZVI) or Fe 0 /GAC reactor.

Automatic ultrasound image enhancement for 2D semi-automatic breast-lesion segmentation

Science.gov (United States)

Lu, Kongkuo; Hall, Christopher S.

2014-03-01

Breast cancer is the fastest growing cancer, accounting for 29%, of new cases in 2012, and second leading cause of cancer death among women in the United States and worldwide. Ultrasound (US) has been used as an indispensable tool for breast cancer detection/diagnosis and treatment. In computer-aided assistance, lesion segmentation is a preliminary but vital step, but the task is quite challenging in US images, due to imaging artifacts that complicate detection and measurement of the suspect lesions. The lesions usually present with poor boundary features and vary significantly in size, shape, and intensity distribution between cases. Automatic methods are highly application dependent while manual tracing methods are extremely time consuming and have a great deal of intra- and inter- observer variability. Semi-automatic approaches are designed to counterbalance the advantage and drawbacks of the automatic and manual methods. However, considerable user interaction might be necessary to ensure reasonable segmentation for a wide range of lesions. This work proposes an automatic enhancement approach to improve the boundary searching ability of the live wire method to reduce necessary user interaction while keeping the segmentation performance. Based on the results of segmentation of 50 2D breast lesions in US images, less user interaction is required to achieve desired accuracy, i.e. < 80%, when auto-enhancement is applied for live-wire segmentation.

Automated 3-D Radiation Mapping

International Nuclear Information System (INIS)

Tarpinian, J. E.

1991-01-01

This work describes an automated radiation detection and imaging system which combines several state-of-the-art technologies to produce a portable but very powerful visualization tool for planning work in radiation environments. The system combines a radiation detection system, a computerized radiation imaging program, and computerized 3-D modeling to automatically locate and measurements are automatically collected and imaging techniques are used to produce colored, 'isodose' images of the measured radiation fields. The isodose lines from the images are then superimposed over the 3-D model of the area. The final display shows the various components in a room and their associated radiation fields. The use of an automated radiation detection system increases the quality of radiation survey obtained measurements. The additional use of a three-dimensional display allows easier visualization of the area and associated radiological conditions than two-dimensional sketches

NIF Ignition Target 3D Point Design

Energy Technology Data Exchange (ETDEWEB)

Jones, O; Marinak, M; Milovich, J; Callahan, D

2008-11-05

We have developed an input file for running 3D NIF hohlraums that is optimized such that it can be run in 1-2 days on parallel computers. We have incorporated increasing levels of automation into the 3D input file: (1) Configuration controlled input files; (2) Common file for 2D and 3D, different types of capsules (symcap, etc.); and (3) Can obtain target dimensions, laser pulse, and diagnostics settings automatically from NIF Campaign Management Tool. Using 3D Hydra calculations to investigate different problems: (1) Intrinsic 3D asymmetry; (2) Tolerance to nonideal 3D effects (e.g. laser power balance, pointing errors); and (3) Synthetic diagnostics.

Quantitative analysis of retina layer elasticity based on automatic 3D segmentation (Conference Presentation)

Science.gov (United States)

He, Youmin; Qu, Yueqiao; Zhang, Yi; Ma, Teng; Zhu, Jiang; Miao, Yusi; Humayun, Mark; Zhou, Qifa; Chen, Zhongping

2017-02-01

Age-related macular degeneration (AMD) is an eye condition that is considered to be one of the leading causes of blindness among people over 50. Recent studies suggest that the mechanical properties in retina layers are affected during the early onset of disease. Therefore, it is necessary to identify such changes in the individual layers of the retina so as to provide useful information for disease diagnosis. In this study, we propose using an acoustic radiation force optical coherence elastography (ARF-OCE) system to dynamically excite the porcine retina and detect the vibrational displacement with phase resolved Doppler optical coherence tomography. Due to the vibrational mechanism of the tissue response, the image quality is compromised during elastogram acquisition. In order to properly analyze the images, all signals, including the trigger and control signals for excitation, as well as detection and scanning signals, are synchronized within the OCE software and are kept consistent between frames, making it possible for easy phase unwrapping and elasticity analysis. In addition, a combination of segmentation algorithms is used to accommodate the compromised image quality. An automatic 3D segmentation method has been developed to isolate and measure the relative elasticity of every individual retinal layer. Two different segmentation schemes based on random walker and dynamic programming are implemented. The algorithm has been validated using a 3D region of the porcine retina, where individual layers have been isolated and analyzed using statistical methods. The errors compared to manual segmentation will be calculated.

Automatic generation of 2D micromechanical finite element model of silicon–carbide/aluminum metal matrix composites: Effects of the boundary conditions

DEFF Research Database (Denmark)

Qing, Hai

2013-01-01

Two-dimensional finite element (FE) simulations of the deformation and damage evolution of Silicon–Carbide (SiC) particle reinforced aluminum alloy composite including interphase are carried out for different microstructures and particle volume fractions of the composites. A program is developed...... for the automatic generation of 2D micromechanical FE-models with randomly distributed SiC particles. In order to simulate the damage process in aluminum alloy matrix and SiC particles, a damage parameter based on the stress triaxial indicator and the maximum principal stress criterion based elastic brittle damage...... model are developed within Abaqus/Standard Subroutine USDFLD, respectively. An Abaqus/Standard Subroutine MPC, which allows defining multi-point constraints, is developed to realize the symmetric boundary condition (SBC) and periodic boundary condition (PBC). A series of computational experiments...

Timing for a sustainable fertilisation of Glycine max by using HBED/Fe3+ and EDDHA/Fe3+ chelates.

Science.gov (United States)

Martín-Fernández, Clara; López-Rayo, Sandra; Hernández-Apaolaza, Lourdes; Lucena, Juan J

2017-07-01

Efficient use of Fe chelates is crucial to avoid environmental risks and reduce economic losses. HBED/Fe 3+ has been recently approved by the European Union for soil fertilisation, but studies delving into the best timing for its application are necessary. In this work, a batch incubation experiment and two biological experiments were developed to determine the optimal physiological stage for a sustainable application of HBED/Fe 3+ in soil fertilisation compared with EDDHA/Fe 3+ fertilisers using 57 Fe. HBED/Fe 3+ demonstrated a high durability in soils and soil materials, maintaining more than 80% of Fe chelated after 70 days, and its application at an early physiological stage resulted in a high Fe accumulation in soybean and soil after 36 days. In contrast, the stability of EDDHA/Fe 3+ decreased because of the retention of its lowest stable isomers. The best timing for chelates application was confirmed in a 52 day experiment. The application of HBED/Fe 3+ at the early stage increased the Fe translocation to fruits; while o,o-EDDHA/Fe 3+ accumulated more Fe in fruits when added at the fructification stage. The high HBED/Fe 3+ stability in calcareous soil requires a differentiate application timing, and its addition at early physiological stages leads into the most efficient fertilisation. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

2:1 Charge disproportionation in perovskite-structure oxide La{sub 1/3}Ca{sub 2/3}FeO{sub 3} with unusually-high-valence Fe{sup 3.67+}

Energy Technology Data Exchange (ETDEWEB)

Guo, Haichuan; Hosaka, Yoshiteru; Seki, Hayato; Saito, Takashi; Ichikawa, Noriya [Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan); Shimakawa, Yuichi, E-mail: shimak@scl.kyoto-u.ac.jp [Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan); Integrated Research Consortium on Chemical Sciences, Uji, Kyoto 611-0011 (Japan)

2017-02-15

La{sub 1/3}Ca{sub 2/3}FeO{sub 3} with unusually-high-valence Fe{sup 3.67+} was synthesized at a high pressure and high temperature. The compound crystallizes in a √2a×2a×√2a perovskite cell in which the La and Ca ions at the A site are disordered. At 217 K the Fe{sup 3.67+} shows charge disproportionation to Fe{sup 3+} and Fe{sup 5+} in a ratio of 2:1, and this disproportionation is accompanied by transitions in magnetic and transport properties. The charge-disproportionated Fe{sup 3+} and Fe{sup 5+} are arranged along the <111> direction of the cubic perovskite cell. The local electronic and magnetic environments of Fe in La{sub 1/3}Ca{sub 2/3}FeO{sub 3} are quite similar to those of Fe in La{sub 1/3}Sr{sub 2/3}FeO{sub 3}, and the 2:1 charge disproportionation pattern of Fe{sup 3+} and Fe{sup 5+} in La{sub 1/3}Ca{sub 2/3}FeO{sub 3} is also the same as that in La{sub 1/3}Sr{sub 2/3}FeO{sub 3}. - Graphical abstract: The perovskite-structure oxide La{sub 1/3}Ca{sub 2/3}FeO{sub 3} with unusually-high-valence Fe{sup 3.67+} shows charge disproportionation to Fe{sup 3+} and Fe{sup 5+} in a ratio of 2:1, and the charge-disproportionated Fe{sup 3+} and Fe{sup 5+} are arranged along the <111> direction of the cubic perovskite cell. - Highlights: • La{sub 1/3}Ca{sub 2/3}FeO{sub 3} with unusually-high-valence Fe{sup 3.67+} was synthesized at a high pressure and high temperature. • At 217 K the Fe{sup 3.67+} shows charge disproportionation (CD) to Fe{sup 3+} and Fe{sup 5+} in a ratio of 2:1. • The charge-disproportionated Fe{sup 3+} and Fe{sup 5+} are arranged along the <111> direction of the cubic perovskite cell. • The disproportionation is accompanied by transitions in magnetic and transport properties.

AUTOCASK (AUTOmatic Generation of 3-D CASK models). A microcomputer based system for shipping cask design review analysis

International Nuclear Information System (INIS)

Gerhard, M.A.; Sommer, S.C.

1995-04-01

AUTOCASK (AUTOmatic Generation of 3-D CASK models) is a microcomputer-based system of computer programs and databases developed at the Lawrence Livermore National Laboratory (LLNL) for the structural analysis of shipping casks for radioactive material. Model specification is performed on the microcomputer, and the analyses are performed on an engineering workstation or mainframe computer. AUTOCASK is based on 80386/80486 compatible microcomputers. The system is composed of a series of menus, input programs, display programs, a mesh generation program, and archive programs. All data is entered through fill-in-the-blank input screens that contain descriptive data requests

AUTOCASK (AUTOmatic Generation of 3-D CASK models). A microcomputer based system for shipping cask design review analysis

Energy Technology Data Exchange (ETDEWEB)

Gerhard, M.A.; Sommer, S.C. [Lawrence Livermore National Lab., CA (United States)

1995-04-01

AUTOCASK (AUTOmatic Generation of 3-D CASK models) is a microcomputer-based system of computer programs and databases developed at the Lawrence Livermore National Laboratory (LLNL) for the structural analysis of shipping casks for radioactive material. Model specification is performed on the microcomputer, and the analyses are performed on an engineering workstation or mainframe computer. AUTOCASK is based on 80386/80486 compatible microcomputers. The system is composed of a series of menus, input programs, display programs, a mesh generation program, and archive programs. All data is entered through fill-in-the-blank input screens that contain descriptive data requests.

Thermodynamic properties of Y/sub 3/Fe/sub 5/O/sub 12/ and TbFeO/sub 3/

Energy Technology Data Exchange (ETDEWEB)

Shchelkotunov, V A; Danilov, V N; Reznitskii, L A; Korobeinikova, A V [Moskovskij Gosudarstvennyj Univ. (USSR)

1975-01-01

Two types of chemical compounds-garnets and perovskites - exist in Fe/sub 2/O/sub 3/-Y/sub 2/O/sub 3/ and Fe/sub 2/O/sub 3/-Tb/sub 2/..omega../sub 3/ systems. Both of them are noncompensated antiferromagnetics. Thermal-physical properties of TbFeO/sub 3/ were determined. Values of Csub(p),(Hsub(t)-Hsub(o)) and Ssub(T) in the temperature range 298 to 700 deg K for Y/sub 3/Fe/sub 5/O/sub 12/ and in the range 298 to 600 deg K for TbFeO/sub 3/ were calculated using the experimental data on TbFeO/sub 3/ and Y/sub 3/Fe/sub 5/O/sub 12/ thermal capacity. Magnetic contribution for Y/sub 3/Fe/sub 5/O/sub 12/ Usub(mag)=1617 cal/mol and ..delta..S=3.44 cal/mol.deg. was determined.

MULTI SENSOR DATA INTEGRATION FOR AN ACCURATE 3D MODEL GENERATION

Directory of Open Access Journals (Sweden)

S. Chhatkuli

2015-05-01

Full Text Available The aim of this paper is to introduce a novel technique of data integration between two different data sets, i.e. laser scanned RGB point cloud and oblique imageries derived 3D model, to create a 3D model with more details and better accuracy. In general, aerial imageries are used to create a 3D city model. Aerial imageries produce an overall decent 3D city models and generally suit to generate 3D model of building roof and some non-complex terrain. However, the automatically generated 3D model, from aerial imageries, generally suffers from the lack of accuracy in deriving the 3D model of road under the bridges, details under tree canopy, isolated trees, etc. Moreover, the automatically generated 3D model from aerial imageries also suffers from undulated road surfaces, non-conforming building shapes, loss of minute details like street furniture, etc. in many cases. On the other hand, laser scanned data and images taken from mobile vehicle platform can produce more detailed 3D road model, street furniture model, 3D model of details under bridge, etc. However, laser scanned data and images from mobile vehicle are not suitable to acquire detailed 3D model of tall buildings, roof tops, and so forth. Our proposed approach to integrate multi sensor data compensated each other’s weakness and helped to create a very detailed 3D model with better accuracy. Moreover, the additional details like isolated trees, street furniture, etc. which were missing in the original 3D model derived from aerial imageries could also be integrated in the final model automatically. During the process, the noise in the laser scanned data for example people, vehicles etc. on the road were also automatically removed. Hence, even though the two dataset were acquired in different time period the integrated data set or the final 3D model was generally noise free and without unnecessary details.

Synthesis, characterization, and comparative gas-sensing properties of Fe{sub 2}O{sub 3} prepared from Fe{sub 3}O{sub 4} and Fe{sub 3}O{sub 4}-chitosan

Energy Technology Data Exchange (ETDEWEB)

Cuong, Nguyen Duc [Faculty of Hospitality and Tourism, Hue University, 22 Lam Hoang, Vy Da Ward, Hue City (Viet Nam); College of Sciences, Hue University, 77 Nguyen Hue, Phu Nhuan Ward, Hue City (Viet Nam); International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST), Hanoi (Viet Nam); Hoa, Tran Thai; Khieu, Dinh Quang [College of Sciences, Hue University, 77 Nguyen Hue, Phu Nhuan Ward, Hue City (Viet Nam); Lam, Tran Dai [Institute of Materials Science, Vietnamese Academy of Science and Technology, Hanoi (Viet Nam); Hoa, Nguyen Duc [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST), Hanoi (Viet Nam); Van Hieu, Nguyen, E-mail: hieu@itims.edu.vn [International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST), Hanoi (Viet Nam)

2012-05-15

Highlights: Black-Right-Pointing-Pointer We have demonstrated a facile method to prepare Fe{sub 3}O{sub 4} nanoparticles and chitosan-coated Fe{sub 3}O{sub 4} nanoparticles. Black-Right-Pointing-Pointer {alpha}-Fe{sub 2}O{sub 3} sensors prepared from those Fe{sub 3}O{sub 4} materials have been investigated and compared. Black-Right-Pointing-Pointer The results show potential application of {alpha}-Fe{sub 2}O{sub 3} for CO sensors in environmental monitoring. - Abstract: In this paper, Fe{sub 3}O{sub 4} and chitosan (CS)-coated Fe{sub 3}O{sub 4} nanoparticles were synthesized via co-precipitation method and subsequent covalent binding of CS onto the surface for functionalization, respectively. Characterization of the crystal structures and morphologies of as-synthesized nanoparticles by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy demonstrated that Fe{sub 3}O{sub 4} had a cubic spinal structure with irregular shapes and average diameters of 10-20 nm. The surface states and magnetic properties of Fe{sub 3}O{sub 4}-CS nanoparticles were characterized by Fourier transform infrared spectra and vibrating sample magnetometry. Results showed that Fe{sub 3}O{sub 4}-CS nanoparticles possessed super-paramagnetic properties, with saturated magnetization up to 60 emu/g. In addition, Fe{sub 3}O{sub 4} and CS-coated Fe{sub 3}O{sub 4} nanoparticles were used in the fabrication of {alpha}-Fe{sub 2}O{sub 3} based gas sensors. Gas sensing measurements revealed that the {alpha}-Fe{sub 2}O{sub 3} gas sensor prepared from Fe{sub 3}O{sub 4}-CS had a better response to H{sub 2}, CO, C{sub 2}H{sub 5}OH, and NH{sub 3} compared with the device prepared from pristine Fe{sub 3}O{sub 4}. Furthermore, the {alpha}-Fe{sub 2}O{sub 3} sensor prepared from Fe{sub 3}O{sub 4}-CS nanoparticles exhibited the highest response to CO among the test gases, suggesting that it has great potential for practical applications in environmental monitoring.

Estimation of aortic valve leaflets from 3D CT images using local shape dictionaries and linear coding

Science.gov (United States)

Liang, Liang; Martin, Caitlin; Wang, Qian; Sun, Wei; Duncan, James

2016-03-01

Aortic valve (AV) disease is a significant cause of morbidity and mortality. The preferred treatment modality for severe AV disease is surgical resection and replacement of the native valve with either a mechanical or tissue prosthetic. In order to develop effective and long-lasting treatment methods, computational analyses, e.g., structural finite element (FE) and computational fluid dynamic simulations, are very effective for studying valve biomechanics. These computational analyses are based on mesh models of the aortic valve, which are usually constructed from 3D CT images though many hours of manual annotation, and therefore an automatic valve shape reconstruction method is desired. In this paper, we present a method for estimating the aortic valve shape from 3D cardiac CT images, which is represented by triangle meshes. We propose a pipeline for aortic valve shape estimation which includes novel algorithms for building local shape dictionaries and for building landmark detectors and curve detectors using local shape dictionaries. The method is evaluated on real patient image dataset using a leave-one-out approach and achieves an average accuracy of 0.69 mm. The work will facilitate automatic patient-specific computational modeling of the aortic valve.

Fe3Nb3N precipitates of the Fe3W3C type in Nb stabilized ferritic stainless steel

International Nuclear Information System (INIS)

Malfliet, A.; Van den Broek, W.; Chassagne, F.; Mithieux, J.-D.; Blanpain, B.; Wollants, P.

2011-01-01

Highlights: → The precipitation in Nb stabilized ferritic stainless steel at 950 deg. C is investigated. → We characterized the Fe 3 Nb 3 X precipitates with SAED, EELS, WDS and AES. → We found that Fe 3 Nb 3 X precipitates are stabilized by N and not by C or O. → This insight is new and important for future development of this type of steel grade. - Abstract: A Nb stabilized ferritic stainless steel with 0.45 wt.%Nb, 82 ppm C and 170 ppm N is investigated to reveal the nature of the precipitates present at 950 deg. C. In particular, Fe 3 Nb 3 X precipitates of the Fe 3 W 3 C type are analyzed with WDS and EELS to determine the light elements X stabilizing this phase in the steel. According to WDS on large precipitates after 500 h at 950 deg. C, the Fe 3 Nb 3 X phase contains 10.4 at.% N, 1.2 at.% O and 1.0 at.% C. Auger Electron Spectroscopy on the same precipitates confirms the presence of N. In addition, it is revealed that the C and O peaks observed with WDS result from surface contamination as they disappear after Ar sputtering. The presence of a N peak in the EELS spectra of small Fe 3 Nb 3 X precipitates which have formed after 6 min at 950 deg. C indicate that N stabilizes this phase already from the initial precipitation stage. With this analysis it is demonstrated that N is an effective stabilizer of Fe 3 Nb 3 X precipitates in ferritic stainless steels. The formation of this phase should therefore be considered when predicting the precipitation behavior of Nb in industrial Nb stabilized ferritic stainless steels containing residual N.

The solubility and site preference of Fe3+ in Li7-3xFexLa3Zr2O12 garnets

Science.gov (United States)

Rettenwander, D.; Geiger, C. A.; Tribus, M.; Tropper, P.; Wagner, R.; Tippelt, G.; Lottermoser, W.; Amthauer, G.

2015-10-01

A series of Fe3+-bearing Li7La3Zr2O12 (LLZO) garnets was synthesized using solid-state synthesis methods. The synthetic products were characterized compositionally using electron microprobe analysis and inductively coupled plasma optical emission spectroscopy (ICP-OES) and structurally using X-ray powder diffraction and 57Fe Mössbauer spectroscopy. A maximum of about 0.25 Fe3+ pfu could be incorporated in Li7-3xFexLa3Zr2O12 garnet solid solutions. At Fe3+ concentrations lower than about 0.16 pfu, both tetragonal and cubic garnets were obtained in the synthesis experiments. X-ray powder diffraction analysis showed only a garnet phase for syntheses with starting materials having intended Fe3+ contents lower than 0.52 Fe3+ pfu. Back-scattered electron images made with an electron microprobe also showed no phase other than garnet for these compositions. The lattice parameter, a0, for all solid-solution garnets is similar with a value of a0≈12.98 Å regardless of the amount of Fe3+. 57Fe Mössbauer spectroscopic measurements indicate the presence of poorly- or nano-crystalline FeLaO3 in syntheses with Fe3+ contents greater than 0.16 Fe3+ pfu. The composition of different phase pure Li7-3xFexLa3Zr2O12 garnets, as determined by electron microprobe (Fe, La, Zr) and ICP-OES (Li) measurements, give Li6.89Fe0.03La3.05Zr2.01O12, Li6.66Fe0.06La3.06Zr2.01O12, Li6.54Fe0.12La3.01Zr1.98O12, and Li6.19Fe0.19La3.02Zr2.04O12. The 57Fe Mössbauer spectrum of cubic Li6.54Fe0.12La3.01Zr1.98O12 garnet indicates that most Fe3+ occurs at the special crystallographic 24d position, which is the standard tetrahedrally coordinated site in garnet. Fe3+ in smaller amounts occurs at a general 96h site, which is only present for certain Li-oxide garnets, and in Li6.54Fe0.12La3.01Zr1.98O12 this Fe3+ has a distorted 4-fold coordination.

High Efficient Photo-Fenton Catalyst of α-Fe2O3/MoS2 Hierarchical Nanoheterostructures: Reutilization for Supercapacitors

Science.gov (United States)

Yang, Xijia; Sun, Haiming; Zhang, Lishu; Zhao, Lijun; Lian, Jianshe; Jiang, Qing

2016-08-01

A novel three-dimensional (3D) α-Fe2O3/MoS2 hierarchical nanoheterostructure is effectively synthesized via a facile hydrothermal method. The zero-dimensional (0D) Fe2O3 nanoparticles guide the growth of two-dimensional (2D) MoS2 nanosheets and formed 3D flower-like structures, while MoS2 facilitates the good dispersion of porous Fe2O3 with abundant oxygen vacancies. This charming 3D-structure with perfect match of non-equal dimension exhibits high recyclable photo-Fenton catalytic activity for Methyl orange pollutant and nice specific capacity in reusing as supercapacitor after catalysis. The synergistic effect between Fe2O3 and MoS2, the intermediate nanointerfaces, the 3D porous structures, and the abundant oxygen vacancies both contribute to highly active catalysis, nice electrochemical performance and stable cycling. This strategy is simple, cheap, and feasible for maximizing the value of the materials, as well as eliminating the secondary pollution.

3dσ vacancy production and sharing in the Fe, Co, Ni, and Cu + Bi collisions

International Nuclear Information System (INIS)

Ciortea, C.; Dumitriu, D.; Enulescu, A.; Fluerasu, D.; Piticu, I.; Szilagyi, S.Z.; Bucur, B.I.; Zoran, V.; McDaniel, F.D.; Marble, D.K.; Sun, Y.

1994-01-01

Available as short communication only. The collision systems Fe, Co, Ni, and Cu + Bi in the energy range 0.1-1.75 MeV/u have been studied by measuring X-ray spectra. Vacancy production cross sections for the K-shell of the projectile and L3-subshell of the target are reported. In the frame of Fano and Lichten model, data for the 3dσ vacancy production and sharing have been obtained. Semiclassical approximation calculations in the united atom version compare favorably with the vacancy production data if the electron binding energy is properly taken into account. The experimental probabilities for vacancy sharing are compared with the predictions of the two-state exponential model of Nikitin. (Author)

Assembly of Fe3O4 nanoparticles on SiO2 monodisperse spheres

Indian Academy of Sciences (India)

Assembly of Fe3O4 nanoparticles on SiO2 monodisperse spheres. K C BARICK and D BAHADUR*. Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay,. Mumbai 400 076, India. Abstract. The assembly of superparamagnetic Fe3O4 nanoparticles on submicroscopic SiO2 ...

Interparticle interactions of FePt core and Fe{sub 3}O{sub 4} shell in FePt/Fe{sub 3}O{sub 4} magnetic nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Akbari, Hossein, E-mail: Akbari.ph@iauardabil.ac.ir [Department of Physics, Ardabil Branch, Islamic Azad University, Ardabil (Iran, Islamic Republic of); Zeynali, Hossein [Department of Physics, Kashan Branch, Islamic Azad University, Kashan (Iran, Islamic Republic of); Bakhshayeshi, Ali [Department of Physics, Mashhad Branch, Islamic Azad University, Mashhad (Iran, Islamic Republic of)

2016-02-22

Monodisperse FePt nanoparticles were successfully synthesized using simple wet chemical method. Fe{sub 3}O{sub 4} was used as a magnetic shell around each FePt nanoparticles. In FePt/Fe{sub 3}O{sub 4} core/shell system, core thickness is 2 nm and shell thickness varies from zero to 2.5 nm. A theoretical model presented to calculate the shell thickness dependence of Coercivity. Presented model is compared with the results from Stoner–Wohlfarth model to interpret the shell thickness dependence of Coercivity in FePt/Fe{sub 3}O{sub 4} core/shell nanoparticles. There is a difference between the results from Stoner–Wohlfarth model and experimental data when the shell thickness increases. In the presented model, the effects of interparticle exchange and random magneto crystalline anisotropy are added to the previous models of magnetization reversal for core/shell nanostructures in order to achieve a better agreement with experimental data. For magnetic shells in FePt/Fe{sub 3}O{sub 4} core/shell, effective coupling between particles increases with increasing shell thickness which leads to Coercivity destruction for stronger couplings. According to the boundary conditions, in the harder regions with higher exchange stiffness, there is small variation in magnetization and so the magnetization modes become more localized. We discussed both localized and non-localized magnetization modes. For non-zero shell thickness, non-localized modes propagate in the soft phase which effects the quality of particle exchange interactions. - Highlights: • Monodisperse FePt nanoparticles were successfully synthesized using simple wet chemical method. • Fe{sub 3}O{sub 4} was used as a magnetic shell around each FePt nanoparticles. • A theoretical model presented to calculate the shell thickness dependence of Coercivity. • Magnetic shells increase effective coupling between particles with increasing shell thickness. • Magnetization modes are more localized in the regions with

Chest wall segmentation in automated 3D breast ultrasound scans.

Science.gov (United States)

Tan, Tao; Platel, Bram; Mann, Ritse M; Huisman, Henkjan; Karssemeijer, Nico

2013-12-01

In this paper, we present an automatic method to segment the chest wall in automated 3D breast ultrasound images. Determining the location of the chest wall in automated 3D breast ultrasound images is necessary in computer-aided detection systems to remove automatically detected cancer candidates beyond the chest wall and it can be of great help for inter- and intra-modal image registration. We show that the visible part of the chest wall in an automated 3D breast ultrasound image can be accurately modeled by a cylinder. We fit the surface of our cylinder model to a set of automatically detected rib-surface points. The detection of the rib-surface points is done by a classifier using features representing local image intensity patterns and presence of rib shadows. Due to attenuation of the ultrasound signal, a clear shadow is visible behind the ribs. Evaluation of our segmentation method is done by computing the distance of manually annotated rib points to the surface of the automatically detected chest wall. We examined the performance on images obtained with the two most common 3D breast ultrasound devices in the market. In a dataset of 142 images, the average mean distance of the annotated points to the segmented chest wall was 5.59 ± 3.08 mm. Copyright © 2012 Elsevier B.V. All rights reserved.

3-D portal image analysis in clinical practice: an evaluation of 2-D and 3-D analysis techniques as applied to 30 prostate cancer patients

International Nuclear Information System (INIS)

Remeijer, Peter; Geerlof, Erik; Ploeger, Lennert; Gilhuijs, Kenneth; Herk, Marcel van; Lebesque, Joos V.

2000-01-01

Purpose: To investigate the clinical importance and feasibility of a 3-D portal image analysis method in comparison with a standard 2-D portal image analysis method for pelvic irradiation techniques. Methods and Materials: In this study, images of 30 patients who were treated for prostate cancer were used. A total of 837 imaged fields were analyzed by a single technologist, using automatic 2-D and 3-D techniques independently. Standard deviations (SDs) of the random, systematic, and overall variations, and the overall mean were calculated for the resulting data sets (2-D and 3-D), in the three principal directions (left-right [L-R], cranial-caudal [C-C], anterior-posterior [A-P]). The 3-D analysis included rotations as well. For the translational differences between the three data sets, the overall SD and overall mean were computed. The influence of out-of-plane rotations on the 2-D registration accuracy was determined by analyzing the difference between the 2-D and 3-D translation data as function of rotations. To assess the reliability of the 2-D and 3-D methods, the number of times the automatic match was manually adjusted was counted. Finally, an estimate of the workload was made. Results: The SDs of the random and systematic components of the rotations around the three orthogonal axes were 1.1 (L-R), 0.6 (C-C), 0.5 (A-P) and 0.9 (L-R), 0.6 (C-C), 0.8 (A-P) degrees, respectively. The overall mean rotation around the L-R axis was 0.7 deg., which deviated significantly from zero. Translational setup errors were comparable for 2-D and 3-D analysis (ranging from 1.4 to 2.2 mm SD and from 1.5 to 2.5 mm SD, respectively). The variation of the difference between the 2-D and 3-D translation data increased from 1.1 mm (SD) for zero rotations to 2.7 mm (SD) for out-of-plane rotations of 3 deg., due to a reduced 2-D registration accuracy for large rotations. The number of times the analysis was not considered acceptable and was manually adjusted was 44% for the 2-D

ROOFN3D: DEEP LEARNING TRAINING DATA FOR 3D BUILDING RECONSTRUCTION

Directory of Open Access Journals (Sweden)

A. Wichmann

2018-05-01

Full Text Available Machine learning methods have gained in importance through the latest development of artificial intelligence and computer hardware. Particularly approaches based on deep learning have shown that they are able to provide state-of-the-art results for various tasks. However, the direct application of deep learning methods to improve the results of 3D building reconstruction is often not possible due, for example, to the lack of suitable training data. To address this issue, we present RoofN3D which provides a new 3D point cloud training dataset that can be used to train machine learning models for different tasks in the context of 3D building reconstruction. It can be used, among others, to train semantic segmentation networks or to learn the structure of buildings and the geometric model construction. Further details about RoofN3D and the developed data preparation framework, which enables the automatic derivation of training data, are described in this paper. Furthermore, we provide an overview of other available 3D point cloud training data and approaches from current literature in which solutions for the application of deep learning to unstructured and not gridded 3D point cloud data are presented.

Raman scattering, magnetization and magnetotransport study of SrFeO3-δ, Sr3Fe2O7-δ and CaFeO3

International Nuclear Information System (INIS)

Damljanovic, Vladimir

2008-01-01

In this thesis we have determined the Raman spectra as well as the magnetization, resistance and magnetoresistance of the compounds SrFeO 3-δ , Sr 3 Fe 2 O 7-δ and CaFeO 3 as a function of temperature. We describe the preparation of nearly stoichiometric SrFeO 3-δ crystals with δ 3.00 in order to assign the phonon modes observed in infra-red experiments. We have measured the Raman spectra of the tetragonal phase in the temperature range 13 K to 300 K and of the orthorhombic phase in the temperature range 6 K to 475 K. We have measured the temperature dependence of the magnetization for the magnetic field along high-symmetry axes of the crystal structure. We have also performed neutron diffraction measurements. The resistivity and the magnetoresistance were measured in the range 10 K to 300 K. Finally we have measured the Raman spectra of the same sample in the temperature range 15 K to 440 K. In order to assign the observed modes, we have performed lattice dynamics calculations based on the published crystal structure of Sr 3 Fe 2 O 7 . (orig.)

Characterisation of a tertiary mixture of {alpha}-Fe{sub 2}O{sub 3}, {gamma}-Fe{sub 2}O{sub 3} and Fe{sub 3}O{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Srinivasan, M.P.; Narasimhan, S.V. [Water and Steam Chemistry Laboratory (Chemistry Group, BARC) BARC Facilities, Kalpakkam, Tamil Nadu 603 102. (India)

1998-12-31

A method has been developed to quantify the individual components of a ternary mixture containing {alpha}-Fe{sub 2}O{sub 3}, {gamma}- Fe{sub 2}O{sub 3} and Fe{sub 3}O{sub 4} based on the preferential dissolution of the components at a fixed time (fixed time - depending on the strength of the chelating agent) in a dilute chemical formulation (containing a chelant and an organic acid) both in presence and absence of reductant. A ternary component diagram was constructed based on the percentage dissolution of the individual components in 2,6-Pyridine dicarboxylic acid (PDCA), Nitrilo triacetic acid (NTA) and EDTA based formulation at 60degC both in presence and absence of reductant. In these formulations, the observed behaviour that the {alpha}-Fe{sub 2}O{sub 3} dissolved very little both in presence and absence of reductant and {gamma}-Fe{sub 2}O{sub 3} dissolved very little in absence of reductant were used for resolving the ternary physical mixture composition. Physical mixtures of Fe{sub 3}O{sub 4}, {alpha}-Fe{sub 2}O{sub 3} and {gamma}-Fe{sub 2}O{sub 3} based on mole ratio were taken such that the total quantity of Fe present would be 1.37 mM for complete dissolution. In presence and absence of reductant, dissolution percentage of Fe observed at fixed time in these formulations, when fit into the already constructed three component phase diagram for each formulation at the same fixed duration, the experimentally resolved composition showed good agreement with that based on individual components. This method is useful to resolve different polymorphs of metal oxides having the metal ions in single and/or multiple oxidation states. (author)

Automatic Plant Annotation Using 3D Computer Vision

DEFF Research Database (Denmark)

Nielsen, Michael

In this thesis 3D reconstruction was investigated for application in precision agriculture where previous work focused on low resolution index maps where each pixel represents an area in the field and the index represents an overall crop status in that area. 3D reconstructions of plants would allow...... reconstruction in occluded areas. The trinocular setup was used for both window correlation based and energy minimization based algorithms. A novel adaption of symmetric multiple windows algorithm with trinocular vision was developed. The results were promising and allowed for better disparity estimations...... on steep sloped surfaces. Also, a novel adaption of a well known graph cut based disparity estimation algorithm with trinocular vision was developed and tested. The results were successful and allowed for better disparity estimations on steep sloped surfaces. After finding the disparity maps each...

Modelling in 3D the olive trees cultures in order to establish the forces (interval) needed for automatic harvesting

Science.gov (United States)

Babanatsas, T.; Glăvan, D. O.; Babanatis Merce, R. M.; Maris, S. A.

2018-01-01

The purpose of this study is to bring as much as possible, close to real situation the 3D modelling for the olive trees in order to establish the necessary forces for automatic harvesting (harvesting robots). To fulfil our goal we have at our disposal different ways to do modelling very close to the real situation. One way is to use reality capture software (its results being photos) that are converted into a real 3D model, the disadvantage of the method being a mesh model that is not accurate enough. The reasonable alternative is to develop an experiment by measuring a sample orchard of olive trees (experiment who took place in Halkidiki, Greece, measuring over 120 trees). After establishing the real dimensions, we adopted as model the media that we have measured (the height of the tree, the thickness of branches, number of branches, etc.), model which we consider closer to the reality and therefor more suitable for our simulation.

Mössbauer Studies of Core-Shell FeO/Fe3O4 Nanoparticles

Science.gov (United States)

Kamzin, A. S.; Valiullin, A. A.; Khurshid, H.; Nemati, Z.; Srikanth, H.; Phan, M. H.

2018-02-01

FeO/Fe3O4 nanoparticles were synthesized by thermal decomposition. Electron microscopy revealed that these nanoparticles were of the core-shell type and had a spherical shape with an average size of 20 nm. It was found that the obtained FeO/Fe3O4 nanoparticles had exchange coupling. The effect of anisotropy on the efficiency of heating (hyperthermic effect) of FeO/Fe3O4 nanoparticles by an external alternating magnetic field was examined. The specific absorption rate (SAR) of the studied nanoparticles was 135 W/g in the experiment with an external alternating magnetic field with a strength of 600 Oe and a frequency of 310 kHz. These data led to an important insight: the saturation magnetization is not the only factor governing the SAR, and the efficiency of heating of magnetic FeO/Fe3O4 nanoparticles may be increased by enhancing the effective anisotropy. Mössbauer spectroscopy of the phase composition of the synthesized nanoparticles clearly revealed the simultaneous presence of three phases: magnetite Fe3O4, maghemite γ-Fe2O3, and wustite FeO.

Reversible Exsolution of Nanometric Fe₂O₃ Particles in BaFe_2-x(PO₄)₂ (0 ≤ x ≤ 2/3):The Logic of Vacancy Ordering in Novel Metal-Depleted Two-Dimensional Lattices

Energy Technology Data Exchange (ETDEWEB)

Alcover, Ignacio Blazquez; David, Rénald; Daviero-Minaud, Sylvie; Filimonov, Dmitry; Huvé, Marielle; Roussel, Pascal; Kabbour, Houria; Mentré, Olivier [CNRS-UMR

2015-08-12

We show here that the exsolution of Fe²⁺ ions out of two-dimensional (2D) honeycomb layers of BaFe₂(PO₄)₂ into iron-deficient BaFe_2–x(PO₄)₂ phases and nanometric α-Fe₂O₃ (typically 50 nm diameter at the grain surface) is efficient and reversible until x = 2/3 in mild oxidizing/reducing conditions. It corresponds to the renewable conversion of 12 wt % of the initial mass into iron oxide. After analyzing single crystal X-ray diffraction data of intermediate members x = 2/7, x = 1/3, x = 1/2 and the ultimate Fe-depleted x = 2/3 term, we then observed a systematic full ordering between Fe ions and vacancies (V_Fe) that denote unprecedented easy in-plane metal diffusion driven by the Fe²⁺/Fe³⁺ redox. Besides the discovery of a diversity of original depleted triangular _∞{Fe^2/3+_2–xO₆} topologies, we propose a unified model correlating the x Fe-removal and the experimental Fe/V_Fe ordering into periodic one-dimensional motifs paving the layers, gaining insights into predictive crystahemistry of complex low dimensional oxides. When we increased the x values it led to a progressive change of the materials from 2D ferromagnets (Fe2+) to 2D ferrimagnets (Fe2/3+) to antiferromagnets for x = 2/3 (Fe3+).

Colorimetric determination of Fe2+/Fe3+ ratio in radioactive glasses

International Nuclear Information System (INIS)

Coleman, C.J.; Baumann, E.W.; Bibler, N.E.

1992-01-01

In the vitrification of nuclear wastes, the Fe 2+ /Fe 3+ ratio in the glass is a measure of the redox properties of the glass melt. It is necessary to measure this ratio to ensure that the melt redox properties are suitable for the glass melter. A colorimetric method for measuring the Fe 2+ /Fe 3+ ratio in highly radioactive glasses was developed and tested remotely in a shielded cell. The tests were performed on glasses similar in composition and radioactivity to those that will be produced in the Savannah River Site Defense Waste Processing Facility. The first step of the method is dissolution of finely crushed glass with a hydrofluoric/sulfuric acid mixture with ammonium vanadate added to preserve the Fe 2+ content of the glass during the dissolution. Boric acid is then added to complex fluoride and to destroy iron-fluoride complexes. After adjusting the solution to pH 5, FerroZine TM (trademark of the Hach Company, Loveland, CO) reagent is added to form a magenta-colored complex with Fe 2+ . The absorbance at 562 nm is measured by using a fiber optic-coupled photodiode array spectrophotometer. Ascorbic acid is then used to reduce all the iron in solution to Fe 2+ and the absorbance is again measured. The difference in absorbance measurements corresponds to the Fe 3+ in the sample and the Fe 2+ /Fe 3+ ratio can be calculated

Photoionization of FE3+ Ions

International Nuclear Information System (INIS)

Ovchinnikov, O.; Schlachter, F.

2003-01-01

Photoionization of Fe3+ ions was studied for the first time using synchrotron radiation from the Advanced Light Source (ALS) and the merged-beams technique. Fe3+ ions were successfully produced using ferrocene in an electron cyclotron resonance ion source (ECR). The measured yield of Fe4+ photoions as a function of photon energy revealed the presence of resonances that correspond to excitation of autoionizing states. These resonances are superimposed upon the photoion yield produced by direct photoionization, which is a smooth, slowly decreasing function of energy. The spectra for the photoionization of Fe3+ will be analyzed and compared with theory. The data collected will also serve to test models for the propagation of light through ionized matter.

Novel room-temperature spin-valve-like magnetoresistance in magnetically coupled nano-column Fe3O4/Ni heterostructure.

Science.gov (United States)

Xiao, Wen; Song, Wendong; Herng, Tun Seng; Qin, Qing; Yang, Yong; Zheng, Ming; Hong, Xiaoliang; Feng, Yuan Ping; Ding, Jun

2016-08-25

Herein, we design a room-temperature spin-valve-like magnetoresistance in a nano-column Fe3O4/Ni heterostructure without using a non-magnetic spacer or pinning layer. An Fe3O4 nano-column film is self-assembled on a Ni underlayer by the thermal decomposition method. The wet-chemical self-assembly is facile, economical and scalable. The magnetoresistance (MR) response of the Ni underlayer in the heterostructure under positive and negative out-of-plane magnetic fields differ by ∼0.25 at room temperature and ∼0.43 at 100 K. We attribute the spin-valve-like magnetoresistance to the unidirectional magnetic anisotropy of the Ni underlayer when being magnetically coupled by the Fe3O4 nano-column film. The out-of-plane negative-field magnetization is higher than the positive-field magnetization, affirming the unidirectional magnetic anisotropy of the Fe3O4/Ni heterostructure. Temperature-dependent magnetic and resistivity studies illustrate a close correlation between the magnetization transition of Fe3O4 and resistivity transition of Ni and prove a magnetic coupling between the Fe3O4 and Ni. First-principles calculations reveal that the Fe3O4/Ni model under a negative magnetic field is energetically more stable than that under a positive magnetic field. Furthermore, partial density of states (PDOS) analysis demonstrates the unidirectional magnetic anisotropy of the Ni 3d orbital. This is induced by the strong ferromagnetic coupling between Fe3O4 and Ni via oxygen-mediated Fe 3d-O 2p-Ni 3d hybridizations.

Intercalating graphene with clusters of Fe3O4 nanocrystals for electrochemical supercapacitors

Science.gov (United States)

Ke, Qingqing; Tang, Chunhua; Liu, Yanqiong; Liu, Huajun; Wang, John

2014-04-01

A hierarchical nanostructure consisting of graphene sheets intercalated by clusters of Fe3O4 nanocystals is developed for high-performance supercapacitor electrode. Here we show that the negatively charged graphene oxide (GO) and positively charged Fe3O4 clusters enable a strong electrostatic interaction, generating a hierarchical 3D nanostructure, which gives rise to the intercalated composites through a rational hydrothermal process. The electrocapacitive behavior of the resultant composites is systematically investigated by cyclic voltammeter and galvanostatic charge-discharge techniques, where a positive synergistic effect between graphene and Fe3O4 clusters is identified. A maximum specific capacitance of 169 F g-1 is achieved in the Fe3O4 clusters decorated with effectively reduced graphene oxide (Fe3O4-rGO-12h), which is much higher than those of rGO (101 F g-1) and Fe3O4 (68 F g-1) at the current density of 1 Ag-1. Moreover, this intercalated hierarchical nanostructure demonstrates a good capacitance retention, retaining over 88% of the initial capacity after 1000 cycles.

Automatic Contour Extraction from 2D Image

Directory of Open Access Journals (Sweden)

Panagiotis GIOANNIS

2011-03-01

Full Text Available Aim: To develop a method for automatic contour extraction from a 2D image. Material and Method: The method is divided in two basic parts where the user initially chooses the starting point and the threshold. Finally the method is applied to computed tomography of bone images. Results: An interesting method is developed which can lead to a successful boundary extraction of 2D images. Specifically data extracted from a computed tomography images can be used for 2D bone reconstruction. Conclusions: We believe that such an algorithm or part of it can be applied on several other applications for shape feature extraction in medical image analysis and generally at computer graphics.

Nano-sized Fe2O3/Fe3O4 facilitate anaerobic transformation of hexavalent chromium in soil-water systems.

Science.gov (United States)

Zhang, Yaxian; Li, Hua; Gong, Libo; Dong, Guowen; Shen, Liang; Wang, Yuanpeng; Li, Qingbiao

2017-07-01

The purpose of this study is to investigate the effects of nano-sized or submicro Fe 2 O 3 /Fe 3 O 4 on the bioreduction of hexavalent chromium (Cr(VI)) and to evaluate the effects of nano-sized Fe 2 O 3 /Fe 3 O 4 on the microbial communities from the anaerobic flooding soil. The results indicated that the net decreases upon Cr(VI) concentration from biotic soil samples amended with nano-sized Fe 2 O 3 (317.1±2.1mg/L) and Fe 3 O 4 (324.0±22.2mg/L) within 21days, which were approximately 2-fold of Cr(VI) concentration released from blank control assays (117.1±5.6mg/L). Furthermore, the results of denaturing gradient gel electrophoresis (DGGE) and high-throughput sequencing indicated a greater variety of microbes within the microbial community in amendments with nano-sized Fe 2 O 3 /Fe 3 O 4 than the control assays. Especially, Proteobacteria occupied a predominant status on the phylum level within the indigenous microbial communities from chromium-contaminated soils. Besides, some partial decrease of soluble Cr(VI) in abiotic nano-sized Fe 2 O 3 /Fe 3 O 4 amendments was responsible for the adsorption of nano-sized Fe 2 O 3 /Fe 3 O 4 to soluble Cr(VI). Hence, the presence of nano-sized Fe 2 O 3 /Fe 3 O 4 could largely facilitate the mobilization and biotransformation of Cr(VI) from flooding soils by adsorption and bio-mediated processes. Copyright © 2017. Published by Elsevier B.V.

Core-Shell Nano structure of a-Fe2O3/Fe3O4: Synthesis and Photo catalysis for Methyl Orange

International Nuclear Information System (INIS)

Tian, Y.; Wu, D.; Yu, B.; Jia, X.; Zhan, S.

2011-01-01

Fe 3 O 4 nanoparticle was synthesized in the solution involving water and ethanol. Then, a-Fe 2 O 3 shell was produced in situ on the surface of the Fe 3 O 4 nanoparticle by surface oxidation in molten salts, forming α-Fe 2 O 3 /Fe 3 O 4 core-shell nano structure. It was showed that the magnetic properties transformed from ferromagnetism to superparamagnetism after the primary Fe 3 O 4 nanoparticles were oxidized. Furthermore, the obtained a-Fe 2 O 3 /Fe 3 O 4 core-shell nanoparticles were used to photo catalyse solution of methyl orange, and the results revealed that a-Fe 2 O 3 /Fe 3 O 4 nanoparticles were more efficient than the self-prepared α-Fe 2 O 3 nanoparticles. At the same time, the photo catalyzer was recyclable by applying an appropriate magnetic field.

Prediction on electronic structure of CH3NH3PbI3/Fe3O4 interfaces

Science.gov (United States)

Hou, Xueyao; Wang, Xiaocha; Mi, Wenbo; Du, Zunfeng

2018-01-01

The interfacial electronic structures of CH3NH3PbI3(MAPbI3)/Fe3O4 heterostructures are predicted by density functional theory. Four models (MAI/FeBO, PbI2/FeBO, MAI/FeA and PbI2/FeA) are included. Especially, a half-metal to semiconductor transition of Fe3O4 appears in PbI2/FeA model. A series of electric field is added to PbI2/FeA model, and a direct-indirect bandgap transition of Fe3O4 appears at a 500-kV/cm field. The electric field can control the bandgap of Fe3O4 in PbI2/FeA model by modulating the hybridization. The prediction of spin-related bandgap characteristic in MAPbI3/Fe3O4 is meaningful for further study.

Effect of Mn Substitution for Multiferroic BiFeO3 Probed by High-Resolution Soft-X-Ray Spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Higuchi, Tohru; Higuchi, T.; Hattori, T.; Sakamoto, W.; Itoh, N.; Shimura, T.; Yogo, T.; Yao, P.; Liu, Y.; Glans, P.; Chang, C.; Wu, Z.; Guo, Jinghua

2008-07-11

The electronic structures of BiFeO{sub 3} (BF) and Mn-doped BiFeO{sub 3} (BF(Mn)) have been studied by X-ray absorption spectroscopy (XAS) and soft-X-ray emission spectroscopy (SXES). The BF and BF(Mn) have the mixed valence state of Fe{sup 2+} and Fe{sup 3+}. The valence band is mainly composed of O 2p state hybridized with the majority-spin t{sub 2g} and e{sub g} orbitals of Fe 3d state. The conduction band is composed of the minority-spin t{sub 2g} and e{sub g} orbitals of Fe 3d. The band gaps of BF and BF(Mn) are estimated to be 1.3 eV and 2.7 eV, respectively. The increase of band gap with Mn substitution contributes to the change of bandwidth of valence band.

Re-entrant spin glass and stepped magnetization in mixed-valence SrFe3(PO4)3

International Nuclear Information System (INIS)

Shang Mingyu; Chen Yan; Tian Ge; Yuan Hongming; Feng Shouhua

2013-01-01

The 2 D channel mixed-valent iron (II/III) monophosphate SrFe 3 (PO 4 ) 3 was synthesized via one step mild hydrothermal method at 210 °C and characterized by X-ray diffraction techniques and magnetization measurements. Coexistence of antiferromagnetic superexchange and ferromagnetic superexchange interactions was supposed to be in the lattice according to the Goodenough-Kanamori-Anderson rules. Temperature dependent DC magnetization measurement shows that SrFe 3 (PO 4 ) 3 is ferrimagnet with three magnetic transitions between 2 and 350 K. Through AC magnetization measurement, re-entrant spin glass was observed due to the competition between ferromagnetic and antiferromagnetic interactions. Furthermore, an interesting field induced stepped magnetization was observed in SrFe 3 (PO 4 ) 3 at 2 K with the saturation magnetization Ms=2.4 μ B /f.u. at 5 T.

Moessbauer determination of magnetic structure of Fe3BO6 crystal

International Nuclear Information System (INIS)

Kovalenko, P.P.; Labushkin, V.G.; Ovsepyan, A.K.; Sarkisov, Eh.R.; Smirnov, E.V.; Prokopov, A.R.; Seleznev, V.N.

1984-01-01

The magnetic structure of a Fe 3 BO 6 crystal belonging to space group Dsub(2h)sup(16)(Psub(nma)) is determined by the Moessbauer γ-radiation diffraction. The bragg reflection (700) of Moessbauer 14.4 keV γ-quanta from the Fe 3 BO 6 monocrystal has been studied experimentally. A high sensitivity of the interference of γ-quantum diffraction scattering on Fe nuclei being in crystallographically non-equivalent 8d- and 4s-positions to the type of magnetic ordering in the crystal is used for determination of the magnetic structure. Agreement of the experimental results with the theoretical calculations, conducted for types of magnetic ordering resolved by the symmetry of the crystal, permitted to reliably determine the magnetic structure of this compound. The results obtained confirm the data of neutrondiffraction studies on magnetic ordering in Fe 3 BO 6 . Advantages of the Moessbauer-diffraction study, as compared to the magnetic neutrondiffraction method, in particular, for investigation of crystals, in which the hyperfine magnetic fields on Fe nuclei have different values, are revealed and discussed in detail

Fabrication and Characterization of 3D-Printed Highly-Porous 3D LiFePO4 Electrodes by Low Temperature Direct Writing Process

Directory of Open Access Journals (Sweden)

Changyong Liu

2017-08-01

Full Text Available LiFePO4 (LFP is a promising cathode material for lithium-ion batteries. In this study, low temperature direct writing (LTDW-based 3D printing was used to fabricate three-dimensional (3D LFP electrodes for the first time. LFP inks were deposited into a low temperature chamber and solidified to maintain the shape and mechanical integrity of the printed features. The printed LFP electrodes were then freeze-dried to remove the solvents so that highly-porous architectures in the electrodes were obtained. LFP inks capable of freezing at low temperature was developed by adding 1,4 dioxane as a freezing agent. The rheological behavior of the prepared LFP inks was measured and appropriate compositions and ratios were selected. A LTDW machine was developed to print the electrodes. The printing parameters were optimized and the printing accuracy was characterized. Results showed that LTDW can effectively maintain the shape and mechanical integrity during the printing process. The microstructure, pore size and distribution of the printed LFP electrodes was characterized. In comparison with conventional room temperature direct ink writing process, improved pore volume and porosity can be obtained using the LTDW process. The electrochemical performance of LTDW-fabricated LFP electrodes and conventional roller-coated electrodes were conducted and compared. Results showed that the porous structure that existed in the printed electrodes can greatly improve the rate performance of LFP electrodes.

Charge-transfer and Mott-Hubbard Excitations in FeBo3: Fe K-edge resonant Inelastic x-ray scattering study

International Nuclear Information System (INIS)

Kim, J.; Shvydko, Y.

2011-01-01

Momentum-resolved resonant inelastic x-ray scattering (RIXS) spectroscopy has been carried out successfully at the Fe K-edge for the first time. The RIXS spectra of a FeBO 3 single crystal reveal a wealth of information on ∼ 1-10 eV electronic excitations. The IXS signal resonates when the incident photon energy approaches the pre-edge (1s - -3d) and the main-edge (1s - -4p) of the Fe K-edge absorption spectrum. The RIXS spectra measured at the pre-edge and the main-edge show quantitatively different dependences on the incident photon energy, momentum transfer, photon polarization, and temperature. We present a multielectron analysis of the Mott-Hubbard (MH) and charge transfer (CT) excitations, and calculate their energies. Electronic excitations observed in the pre-edge and main-edge RIXS spectra are interpreted as MH and CT excitations, respectively. We propose the electronic structure around the chemical potential in FeBO 3 based on the experimental data.

Facile Preparation, Characterization, and Highly Effective Microwave Absorption Performance of CNTs/Fe3O4/PANI Nanocomposites

Directory of Open Access Journals (Sweden)

Deqing Zhang

2013-01-01

Full Text Available A facile method has been developed to synthesize light-weight CNTs/Fe3O4/PANI nanocomposites. The formation route was proposed as the coprecipitation of Fe2+ and Fe3+ and an additional process of in situ polymerization of aniline monomer. The structure and morphology of CNTs/Fe3O4/PANI were characterized by transmission electron microscopy (TEM, X-ray photoelectron spectroscopy (XPS, and Fourier transform infrared (FTIR spectroscopy. The TEM investigation shows that the CNTs/Fe3O4/PANI nanocomposites exhibit less intertwined structure and that many more Fe3O4 particles are attached homogeneously on the surface of CNTs, indicating that PANI can indeed help CNTs to disperse in isolated form. The wave-absorbing properties were investigated in a frequency of 2–18 GHz. The results show that the CNTs/Fe3O4/PANI nanocomposites exhibit a super absorbing behavior and possess a maximum reflection loss of −48 dB at 12.9 GHz, and the bandwidth below −20 dB is more than 5 GHz. More importantly, the absorption peak frequency ranges of the CNTs/Fe3O4/PANI composites can be tuned easily by changing the wax weight ratio and thickness of CNTs/Fe3O4/PANI paraffin wax matrix.

Automatic Texture Optimization for 3D Urban Reconstruction

Directory of Open Access Journals (Sweden)

LI Ming

2017-03-01

Full Text Available In order to solve the problem of texture optimization in 3D city reconstruction by using multi-lens oblique images, the paper presents a method of seamless texture model reconstruction. At first, it corrects the radiation information of images by camera response functions and image dark channel. Then, according to the corresponding relevance between terrain triangular mesh surface model to image, implements occlusion detection by sparse triangulation method, and establishes the triangles' texture list of visible. Finally, combines with triangles' topology relationship in 3D triangular mesh surface model and means and variances of image, constructs a graph-cuts-based texture optimization algorithm under the framework of MRF(Markov random filed, to solve the discrete label problem of texture optimization selection and clustering, ensures the consistency of the adjacent triangles in texture mapping, achieves the seamless texture reconstruction of city. The experimental results verify the validity and superiority of our proposed method.

Towards Rapid Generation and Visualisation of Large 3D Urban Landscapes for Mobile Device Navigation

OpenAIRE

Brujic-Okretic, V.; Gatzidis, C.; Liarokapis, F.; Baker, S.

2008-01-01

In this paper a procedural 3D modelling solution for mobile devices is presented based on scripting algorithms allowing for both the automatic and also semi-automatic creation of photorealistic quality virtual urban content. The combination of aerial images, GIS data, 2D ground maps and terrestrial photographs as input data coupled with a user-friendly customized interface permits the automatic and interactive generation of large-scale, accurate, georeferenced and fully-textured 3D virtual ci...

Automatic radioxenon analyzer for CTBT monitoring

International Nuclear Information System (INIS)

Bowyer, T.W.; Abel, K.H.; Hensley, W.K.

1996-12-01

Over the past 3 years, with support from US DOE's NN-20 Comprehensive Test Ban Treaty (CTBT) R ampersand D program, PNNL has developed and demonstrated a fully automatic analyzer for collecting and measuring the four Xe radionuclides, 131m Xe(11.9 d), 133m Xe(2.19 d), 133 Xe (5.24 d), and 135 Xe(9.10 h), in the atmosphere. These radionuclides are important signatures in monitoring for compliance to a CTBT. Activity ratios permit discriminating radioxenon from nuclear detonation and that from nuclear reactor operations, nuclear fuel reprocessing, or medical isotope production and usage. In the analyzer, Xe is continuously and automatically separated from the atmosphere at flow rates of about 7 m 3 /h on sorption bed. Aliquots collected for 6-12 h are automatically analyzed by electron-photon coincidence spectrometry to produce sensitivities in the range of 20-100 μBq/m 3 of air, about 100-fold better than with reported laboratory-based procedures for short time collection intervals. Spectral data are automatically analyzed and the calculated radioxenon concentrations and raw gamma- ray spectra automatically transmitted to data centers

Fe uptake from meso and D,L-racemic Fe(o,o-EDDHA) isomers by strategy I and II plants.

Science.gov (United States)

Cerdán, Mar; Alcañiz, Sara; Juárez, Margarita; Jordá, Juana D; Bermúdez, Dolores

2006-02-22

One of the most efficient fertilizers to correct Fe deficiency in calcareous soils and waters with high bicarbonate content is based on ferric ethylenediamine-N,N'-bis(o-hydroxyphenylacetic) acid [Fe(o,o-EDDHA)]. Fe(o,o-EDDHA) forms two groups of geometric isomers known as meso and D,L-racemic. To determine the Fe uptake from meso and D,L-racemic Fe(o,o-EDDHA), four iron-efficient plants, two plants representative of strategy I (tomato and pepper) and two plants representative of strategy II (wheat and oats), were grown in hydroponic culture. Results indicated that strategy II plants took up iron from both Fe(o,o-EDDHA) isomers equally. However, strategy I plants took mainly the iron associated with the meso form (the lowest stability isomer).

Tunneling magnetoresistance in Fe{sub 3}Si/MgO/Fe{sub 3}Si(001) magnetic tunnel junctions

Energy Technology Data Exchange (ETDEWEB)

Tao, L. L.; Liang, S. H.; Liu, D. P.; Wei, H. X.; Han, X. F., E-mail: xfhan@iphy.ac.cn [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Wang, Jian [Department of Physics and the Center of Theoretical and Computational Physics, The University of Hong Kong, Hong Kong (China)

2014-04-28

We present a theoretical study of the tunneling magnetoresistance (TMR) and spin-polarized transport in Fe{sub 3}Si/MgO/Fe{sub 3}Si(001) magnetic tunnel junction (MTJ). It is found that the spin-polarized conductance and bias-dependent TMR ratios are rather sensitive to the structure of Fe{sub 3}Si electrode. From the symmetry analysis of the band structures, we found that there is no spin-polarized Δ{sub 1} symmetry bands crossing the Fermi level for the cubic Fe{sub 3}Si. In contrast, the tetragonal Fe{sub 3}Si driven by in-plane strain reveals half-metal nature in terms of Δ{sub 1} state. The giant TMR ratios are predicted for both MTJs with cubic and tetragonal Fe{sub 3}Si electrodes under zero bias. However, the giant TMR ratio resulting from interface resonant transmission for the former decreases rapidly with the bias. For the latter, the giant TMR ratio can maintain up to larger bias due to coherent transmission through the majority-spin Δ{sub 1} channel.

MIL-100-Fe derived N-doped Fe/Fe3C@C electrocatalysts for efficient oxygen reduction reaction

Science.gov (United States)

Guo, Dakai; Han, Sancan; Wang, Jiacheng; Zhu, Yufang

2018-03-01

N-doped porous Fe/Fe3C@C electrocatalysts were prepared by the pyrolysis of the hexamethylenetetramine (HMT)-incorporated MIL-100-Fe at different temperatures (700-1000 °C) under N2 atmosphere. Rotary evaporation of MIL-100-Fe and HMT solution could make more N-enriched HMT molecules enter into the pores of MIL-100-Fe, thus improving nitrogen contents of the final pyrolyzed samples. All pyrolyzed samples show porous textures with middle specific surface areas. The X-ray photoelectron spectroscopy (XPS) results demonstrate the successful introduction of N atoms into carbon framework. Sample Fe-N2-800 prepared by annealing the precursors with the HMT/MIL-100-Fe weight ratio of 2 at 800 °C exhibits the best electrocatalytic activity towards the oxygen reduction reaction (ORR) in terms of onset potential and current density because of high graphitic N and pyridinic N content. The enwrapped Fe/Fe3C nanoparticles and Fe-Nx active sites in these samples could also boost the ORR activity synergistically. Moreover, sample Fe-N2-800 demonstrates a dominant four electron reduction process, as well as excellent long-term operation stability and methanol crossover resistance. Thus, the N-doped Fe/Fe3C@C composites derived from the HMT-incorporated MIL-100-Fe are promising electrocatalysts to replace Pt/C for ORR in practical applications.

3d-metal doping (Fe,Co,Ni,Zn) of the high Tc perovskite YBa2Cu3O(7-y)

International Nuclear Information System (INIS)

Tarascon, J.M.; Barboux, P.; Greene, L.H.; Hull, G.W.; Bagley, B.G.

1988-01-01

The structural, magnetic and superconducting properties of the mixed compounds YBa 2 Cu(3-x)M(x)O(7-y) (M = Ni,Zn,Fe, and Co) are reported. Values of y, determined by titration, are found to be dependent on the nature and amount of the doping. The range of solubility is greater for the Fe and Co compounds (x = 1) than for those with Ni or Zn (x = 0.3). The undoped material is orthorhombic and remains orthorhombic after substitution for Cu by Ni or Zn, whereas a tetragonal phase is observed when Fe, Co are substituted for Cu. DC resistance and AC susceptibility measurements show that Tc is depressed from 90K (x = 0) to 45K (x = 0.2) for both the Ni- and Zn-doped compounds, and Tc is destroyed in the Fe- and Co-doped compounds when x reaches 0.4. It is suggested that a valence of two be assigned to the Ni and Zn and three to the Fe and Co ions. 8 references

Magnetic epoxy nanocomposites reinforced with hierarchical α-Fe2O3 nanoflowers: a study of mechanical properties

Science.gov (United States)

Balguri, Praveen Kumar; Harris Samuel, D. G.; Thumu, Udayabhaskararao

2017-09-01

In this work, we presented the potentiality of monodispersed 3D hierarchical α-Fe2O3 nanoflowers (α-Fe2O3) as reinforcement for epoxy polymer. α-Fe2O3 are synthesized through the thermal decomposition of iron alkoxide precursor in ethylene glycol. α-Fe2O3/epoxy nanocomposites (0.1 wt% of α-Fe2O3) show 109%, 59%, 13%, and 15% enhancement in impact (un-notched), impact (notched), flexural and tensile properties, respectively. The uniformly embedded α- Fe2O3 nanoflowers in epoxy polymer not only provide mechanical strength but also induced magnetic nature to the nanocomposite as observed from the Scanning electron microscopy and vibrating sample magnetometer.

3D Biofabrication of Thermoplastic Polyurethane (TPU/Poly-l-lactic Acid (PLLA Electrospun Nanofibers Containing Maghemite (γ-Fe2O3 for Tissue Engineering Aortic Heart Valve

Directory of Open Access Journals (Sweden)

Ehsan Fallahiarezoudar

2017-11-01

Full Text Available Valvular dysfunction as the prominent reason of heart failure may causes morbidity and mortality around the world. The inability of human body to regenerate the defected heart valves necessitates the development of the artificial prosthesis to be replaced. Besides, the lack of capacity to grow, repair or remodel of an artificial valves and biological difficulty such as infection or inflammation make the development of tissue engineering heart valve (TEHV concept. This research presented the use of compound of poly-l-lactic acid (PLLA, thermoplastic polyurethane (TPU and maghemite nanoparticle (γ-Fe2O3 as the potential biomaterials to develop three-dimensional (3D aortic heart valve scaffold. Electrospinning was used for fabricating the 3D scaffold. The steepest ascent followed by the response surface methodology was used to optimize the electrospinning parameters involved in terms of elastic modulus. The structural and porosity properties of fabricated scaffold were characterized using FE-SEM and liquid displacement technique, respectively. The 3D scaffold was then seeded with aortic smooth muscle cells (AOSMCs and biological behavior in terms of cell attachment and proliferation during 34 days of incubation was characterized using MTT (3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide assay and confocal laser microscopy. Furthermore, the mechanical properties in terms of elastic modulus and stiffness were investigated after cell seeding through macro-indentation test. The analysis indicated the formation of ultrafine quality of nanofibers with diameter distribution of 178 ± 45 nm and 90.72% porosity. In terms of cell proliferation, the results exhibited desirable proliferation (109.32 ± 3.22% compared to the control of cells over the 3D scaffold in 34 days of incubation. The elastic modulus and stiffness index after cell seeding were founded to be 22.78 ± 2.12 MPa and 1490.9 ± 12 Nmm2, respectively. Overall, the fabricated 3D

Electroless siliconizing Fe-3% Cr-3% Si alloy

International Nuclear Information System (INIS)

Nurlina, Enung; Darmono, Budy; Purwadaria, Sunara

2000-01-01

In this research Fe-3%Cr-3%Mo-3%Si and Fe-3%Cr-3%Cu-3%Si alloys had been coated by silicon metal without electricity current which knows as electroless siliconizing. Coating was conducted by immersed sampler into melt fluoride-chloride salt bath at temperature of 750 o C for certain period. The layer consisted of Fe3Si phase. Observation by microscope optic and EDAX showed that the silicide layer were thick enough, adherent, free for crack and had silicon content on the surface more than 15%. The growth rate of silicide layer followed parabolic rate law, where the process predominantly controlled by interdiffusion rate in the solid phase. Key words : electroless siliconizing, the melt fluoride- chloride salt mix, silicide layer

Site occupancy and magnetic study of Al3+ and Cr3+ co-substituted Y3Fe5O12

International Nuclear Information System (INIS)

Bouziane, K.; Yousif, A.; Widatallah, H.M.; Amighian, J.

2008-01-01

Single-phased polycrystalline Y 3 Fe 5-2x Al x Cr x O 12 garnet samples (x=0, 0.2, 0.4 and 0.6) have been prepared by the conventional ceramic technique. Rietveld refinement of X-ray diffraction patterns of the samples shows them to crystallize in the Ia3d space group and the corresponding lattice constant to decrease with increasing Al 3+ and Cr 3+ contents (x). Moessbauer results indicate that Cr 3+ substitutes for Fe 3+ at the octahedral sites whilst Al 3+ essentially replaces Fe 3+ at the tetrahedral sites. This result indicates that co-doping of Y 3 Fe 5 O 12 does not affect the preferential site occupancy for separate individual substitution of either Cr 3+ or Al 3+ . The magnetization measurements reveal that the Curie temperature (T c ) monotonically decreases with increasing x while the magnetic moment per unit formula decreases up to x=0.4 and then slightly increases for x=0.6. This reflects a progressive weakening of the ferrimagnetic exchange interaction between the Fe 3+ ions at octahedral and tetrahedral sites due to co-substitution. The magnetic moment was calculated using the cations distribution inferred from the Moessbauer data and the collinear ferrimagnetic model, and was found to agree reasonably with the experimentally measured value. The phenomenological amplitude crossover, characterized by the temperature T*, has also been observed in the doped YIG and briefly discussed

Investigation of the Morin transition in α-Fe2O3 by the Moessbauer effect

International Nuclear Information System (INIS)

Tobler, L.; Kuendig, W.; Savic, I.

1981-01-01

Hematite (α-Fe 2 O 3 ) is an antiferromagnet with the corundum structure D 63 sub(d). Below the Morin temperature (Tsub(M) approx. equal to 260 K) the Fe-spins are parallel to the trigonal axis. Between Tsub(M) and the Neel temperature (Tsub(N) = 960 K), the spins lie in the basal plane. A small angle between the spins of the two magnetic sublattices leads to a weak ferromagnetism at T > Tsub(M). In the experiment to be described the Morin transition was investigated by the Moessbauer effect. This work was stimulated by μSR-investigations on α-Fe 2 O 3 . (orig.)

In-Plane Magnetic Anisotropy of Fe Atoms on Bi2Se3 (111)

DEFF Research Database (Denmark)

Honolka, J.; Khajetoorians, A.A.; Sessi, V.

2012-01-01

The robustness of the gapless topological surface state hosted by a 3D topological insulator against perturbations of magnetic origin has been the focus of recent investigations. We present a comprehensive study of the magnetic properties of Fe impurities on the prototypical 3D topological insula...

Two sugar-rhodamine "turn-on" fluorescent probes for the selective detection of Fe3 +

Science.gov (United States)

Chen, Qing; Fang, Zhijie

2018-03-01

Two new sugar-rhodamine fluorescent probes (RDG1 and RDG2) have been synthesized and characterized by 1H NMR, 13C NMR and HRMS. Their UV-Vis, fluorescence spectra and fluorescence-response to Fe3 + are investigated and discussed. RDG1 had a very nice linear relationship between UV absorbance and Fe3 + concentration with the correlation coefficient as high as 0.997 and the detection limit is 3.46 × 10- 6 M. Upon the addition of Fe3 +, the spirolactam ring of RDG1 was opened and a 1:1 metal ligand complex was formed from Job's plot. The results showed that RDG1 can be used as an effective fluorescent probe for selective detection of Fe3 + in water. RDG2 was incorporated the well-known rhodamine group and a water-soluble D-glucose group within one molecule and can be used for detecting Fe3 + in natural water as a selective fluorescent sensor. The addition of Fe3 + into RDG2 resulted in a strongly enhanced fluorescence as well as color change of solution from colorless to pink. Job's plot of RDG2 indicated 1:1 stoichiometry of RDG2-Fe3 +. RDG2 can serve as a probe for Fe3 + between pH = 4.0 to 7.0 and it's detection limit is 2.09 × 10- 6 M. The OFF-ON fluorescent mechanisms of RDG1-Fe3 + and RDG2-Fe3 + are proposed.

New insights into the short pitch corrugation development enigma based on 3D-FE dynamic vehicle-track coupled modelling in frictional rolling contact

NARCIS (Netherlands)

Li, S.; Li, Z.; Nunez Vicencio, Alfredo; Dollevoet, R.P.B.J.

2017-01-01

A three-dimensional (3D) finite element (FE) dynamic frictional rolling contact model is presented for the study of short pitch corrugation that considers direct and instantaneous coupling between the contact mechanics and the structural dynamics in a vehicle-track system. In this study, we examine

Automatic Evaluation of Photovoltaic Power Stations from High-Density RGB-T 3D Point Clouds

Directory of Open Access Journals (Sweden)

Luis López-Fernández

2017-06-01

Full Text Available A low-cost unmanned aerial platform (UAV equipped with RGB (Red, Green, Blue and thermographic sensors is used for the acquisition of all the data needed for the automatic detection and evaluation of thermal pathologies on photovoltaic (PV surfaces and geometric defects in the mounting on photovoltaic power stations. RGB imagery is used for the generation of a georeferenced 3D point cloud through digital image preprocessing, photogrammetric and computer vision algorithms. The point cloud is complemented with temperature values measured by the thermographic sensor and with intensity values derived from the RGB data in order to obtain a multidimensional product (5D: 3D geometry plus temperature and intensity on the visible spectrum. A segmentation workflow based on the proper integration of several state-of-the-art geomatic and mathematic techniques is applied to the 5D product for the detection and sizing of thermal pathologies and geometric defects in the mounting in the PV panels. It consists of a three-step segmentation procedure, involving first the geometric information, then the radiometric (RGB information, and last the thermal data. No configuration of parameters is required. Thus, the methodology presented contributes to the automation of the inspection of PV farms, through the maximization of the exploitation of the data acquired in the different spectra (visible and thermal infrared bands. Results of the proposed workflow were compared with a ground truth generated according to currently established protocols and complemented with a topographic survey. The proposed methodology was able to detect all pathologies established by the ground truth without adding any false positives. Discrepancies in the measurement of damaged surfaces regarding established ground truth, which can reach the 5% of total panel surface for the visual inspection by an expert operator, decrease with the proposed methodology under the 2%. The geometric evaluation

From Point Clouds to Building Information Models: 3D Semi-Automatic Reconstruction of Indoors of Existing Buildings

Directory of Open Access Journals (Sweden)

Hélène Macher

2017-10-01

Full Text Available The creation of as-built Building Information Models requires the acquisition of the as-is state of existing buildings. Laser scanners are widely used to achieve this goal since they permit to collect information about object geometry in form of point clouds and provide a large amount of accurate data in a very fast way and with a high level of details. Unfortunately, the scan-to-BIM (Building Information Model process remains currently largely a manual process which is time consuming and error-prone. In this paper, a semi-automatic approach is presented for the 3D reconstruction of indoors of existing buildings from point clouds. Several segmentations are performed so that point clouds corresponding to grounds, ceilings and walls are extracted. Based on these point clouds, walls and slabs of buildings are reconstructed and described in the IFC format in order to be integrated into BIM software. The assessment of the approach is proposed thanks to two datasets. The evaluation items are the degree of automation, the transferability of the approach and the geometric quality of results of the 3D reconstruction. Additionally, quality indexes are introduced to inspect the results in order to be able to detect potential errors of reconstruction.

DYNA3D2000*, Explicit 3-D Hydrodynamic FEM Program

International Nuclear Information System (INIS)

Lin, J.

2002-01-01

1 - Description of program or function: DYNA3D2000 is a nonlinear explicit finite element code for analyzing 3-D structures and solid continuum. The code is vectorized and available on several computer platforms. The element library includes continuum, shell, beam, truss and spring/damper elements to allow maximum flexibility in modeling physical problems. Many materials are available to represent a wide range of material behavior, including elasticity, plasticity, composites, thermal effects and rate dependence. In addition, DYNA3D has a sophisticated contact interface capability, including frictional sliding, single surface contact and automatic contact generation. 2 - Method of solution: Discretization of a continuous model transforms partial differential equations into algebraic equations. A numerical solution is then obtained by solving these algebraic equations through a direct time marching scheme. 3 - Restrictions on the complexity of the problem: Recent software improvements have eliminated most of the user identified limitations with dynamic memory allocation and a very large format description that has pushed potential problem sizes beyond the reach of most users. The dominant restrictions remain in code execution speed and robustness, which the developers constantly strive to improve

View Invariant Gesture Recognition using 3D Motion Primitives

DEFF Research Database (Denmark)

Holte, Michael Boelstoft; Moeslund, Thomas B.

2008-01-01

This paper presents a method for automatic recognition of human gestures. The method works with 3D image data from a range camera to achieve invariance to viewpoint. The recognition is based solely on motion from characteristic instances of the gestures. These instances are denoted 3D motion...

Uniform Fe3O4 coating on flower-like ZnO nanostructures by atomic layer deposition for electromagnetic wave absorption.

Science.gov (United States)

Wan, Gengping; Wang, Guizhen; Huang, Xianqin; Zhao, Haonan; Li, Xinyue; Wang, Kan; Yu, Lei; Peng, Xiange; Qin, Yong

2015-11-21

An elegant atomic layer deposition (ALD) method has been employed for controllable preparation of a uniform Fe3O4-coated ZnO (ZnO@Fe3O4) core-shell flower-like nanostructure. The Fe3O4 coating thickness of the ZnO@Fe3O4 nanostructure can be tuned by varying the cycle number of ALD Fe2O3. When serving as additives for microwave absorption, the ZnO@Fe3O4-paraffin composites exhibit a higher absorption capacity than the ZnO-paraffin composites. For ZnO@500-Fe3O4, the effective absorption bandwidth below -10 dB can reach 5.2 GHz and the RL values below -20 dB also cover a wide frequency range of 11.6-14.2 GHz when the coating thickness is 2.3 mm, suggesting its potential application in the treatment of the electromagnetic pollution problem. On the basis of experimental observations, a mechanism has been proposed to understand the enhanced microwave absorption properties of the ZnO@Fe3O4 composites.

Enhanced saturation magnetization of Fe{sub 3}Si nanodot-embedded Fe{sub 80}Si{sub 17}Nb{sub 3} flexible film for efficient wireless power transfer

Energy Technology Data Exchange (ETDEWEB)

Pai, Yi-Hao, E-mail: paiyihao@mail.ndhu.edu.tw; Yan, Zih-Yu; Fu, Ping-Hao

2013-07-15

An efficient magnetically coupled resonance response is performed using an iron silicide-based nanostructured magnetoelectric material with high saturation magnetization for the wireless charging of battery-powered consumer electronics. With 500 °C annealing, the self-assembled Fe{sub 3}Si nanodots buried in the Fe{sub 80}Si{sub 17}Nb{sub 3} host matrix with (220) lattice spacing of 1.99 Å corresponding to a volume density of 8.96 × 10{sup 16} cm{sup 3}, can be obtained and a maximum saturation magnetization of 244 emu g{sup −1} achieved. The return loss of the antenna will be tuned to match the designed frequency with greater attenuated intensity (−0.39 dB) and a relatively narrow bandwidth (6 kHz) when the Fe{sub 3}Si nanodot-embedded Fe{sub 80}Si{sub 17}Nb{sub 3} sample is placed in a WiTricity system. An efficient wireless power transfer can be created and improved from 47.5% to 97.3%. The associated coil and loop antenna resonators are significantly readjusted to match the power transfer by putting this nanostructured magnetoelectric material in a WiTricity system. - Highlights: • The saturation magnetization is effective enhancement in the presence of Fe{sub 3}Si nanodot buried in the Fe{sub 80}Si{sub 17}Nb{sub 3}. • A saturation magnetization of 244 emu g{sup −1} is proposed for high-efficiency wireless power transfer. • The return loss of the antenna will be tuned to match the designed frequency. • Such a wireless power transfer can be enhanced efficiency up to 97.3%.

Electronic and magnetic properties of Si substituted Fe3Ge

International Nuclear Information System (INIS)

Shanavas, K. V.; McGuire, Michael A.; Parker, David S.

2015-01-01

Using first principles calculations, we studied the effect of Si substitution in the hexagonal Fe 3 Ge. We find the low temperature magnetic anisotropy in this system to be planar and originating mostly from the spin-orbit coupling in Fe-d states. Reduction of the unitcell volume reduces the magnitude of in-plane magnetic anisotropy, eventually turning it positive which reorients the magnetic moments to the axial direction. Substituting Ge with the smaller Si ions also increases the anisotropy, potentially enhancing the region of stability of the axial magnetization, which is beneficial for magnetic applications such as permanent magnets. Our experimental measurements on samples of Fe 3 Ge 1−x Si x confirm these predictions and show that substitution of about 6% of the Ge with Si increases by approximately 35 K the temperature range over which anisotropy is uniaxial

Spin-Related Micro-Photoluminescence in Fe3+ Doped ZnSe Nanoribbons

Directory of Open Access Journals (Sweden)

Lipeng Hou

2016-12-01

Full Text Available Spin-related emission properties have important applications in the future information technology; however, they involve microscopic ferromagnetic coupling, antiferromagnetic or ferrimagnetic coupling between transition metal ions and excitons, or d state coupling with phonons is not well understood in these diluted magnetic semiconductors (DMS. Fe3+ doped ZnSe nanoribbons, as a DMS example, have been successfully prepared by a thermal evaporation method. Their power-dependent micro-photoluminescence (PL spectra and temperature-dependent PL spectra of a single ZnSe:Fe nanoribbon have been obtained and demonstrated that alio-valence ion doping diminishes the exciton magnetic polaron (EMP effect by introducing exceeded charges. The d-d transition emission peaks of Fe3+ assigned to the 4T2 (G → 6A1 (S transition at 553 nm and 4T1 (G → 6A1 (S transition at 630 nm in the ZnSe lattice have been observed. The emission lifetimes and their temperature dependences have been obtained, which reflected different spin–phonon interactions. There exists a sharp decrease of PL lifetime at about 60 K, which hints at a magnetic phase transition. These spin–spin and spin–phonon interaction related PL phenomena are applicable in the future spin-related photonic nanodevices.

Relating the 3D electrode morphology to Li-ion battery performance; a case for LiFePO4

Science.gov (United States)

Liu, Zhao; Verhallen, Tomas W.; Singh, Deepak P.; Wang, Hongqian; Wagemaker, Marnix; Barnett, Scott

2016-08-01

One of the main goals in lithium ion battery electrode design is to increase the power density. This requires insight in the relation between the complex heterogeneous microstructure existing of active material, conductive additive and electrolyte providing the required electronic and Li-ion transport. FIB-SEM is used to determine the three phase 3D morphology, and Li-ion concentration profiles obtained with Neutron Depth Profiling (NDP) are compared for two cases, conventional LiFePO4 electrodes and better performing carbonate templated LiFePO4 electrodes. This provides detailed understanding of the impact of key parameters such as the tortuosity for electron and Li-ion transport though the electrodes. The created hierarchical pore network of the templated electrodes, containing micron sized pores, appears to be effective only at high rate charge where electrolyte depletion is hindering fast discharge. Surprisingly the carbonate templating method results in a better electronic conductive CB network, enhancing the activity of LiFePO4 near the electrolyte-electrode interface as directly observed with NDP, which in a large part is responsible for the improved rate performance both during charge and discharge. The results demonstrate that standard electrodes have a far from optimal charge transport network and that significantly improved electrode performance should be possible by engineering the microstructure.

Rapid 3D Modeling and Parts Recognition on Automotive Vehicles Using a Network of RGB-D Sensors for Robot Guidance

Directory of Open Access Journals (Sweden)

Alberto Chávez-Aragón

2013-01-01

Full Text Available This paper presents an approach for the automatic detection and fast 3D profiling of lateral body panels of vehicles. The work introduces a method to integrate raw streams from depth sensors in the task of 3D profiling and reconstruction and a methodology for the extrinsic calibration of a network of Kinect sensors. This sensing framework is intended for rapidly providing a robot with enough spatial information to interact with automobile panels using various tools. When a vehicle is positioned inside the defined scanning area, a collection of reference parts on the bodywork are automatically recognized from a mosaic of color images collected by a network of Kinect sensors distributed around the vehicle and a global frame of reference is set up. Sections of the depth information on one side of the vehicle are then collected, aligned, and merged into a global RGB-D model. Finally, a 3D triangular mesh modelling the body panels of the vehicle is automatically built. The approach has applications in the intelligent transportation industry, automated vehicle inspection, quality control, automatic car wash systems, automotive production lines, and scan alignment and interpretation.

Direct band gaps in multiferroic h-LuFeO3

International Nuclear Information System (INIS)

Holinsworth, B. S.; Mazumdar, D.; Musfeldt, J. L.; Brooks, C. M.; Mundy, J. A.; Das, H.; Fennie, C. J.; Cherian, J. G.; McGill, S. A.; Schlom, D. G.

2015-01-01

We measured the optical properties of epitaxial thin films of the metastable hexagonal polymorph of LuFeO 3 by absorption spectroscopy, magnetic circular dichroism, and photoconductivity. Comparison with complementary electronic structure calculations reveals a 1.1 eV direct gap involving hybridized Fe 3d z 2 +O 2p z →Fe d excitations at the Γ and A points, with a higher energy direct gap at 2.0 eV. Both charge gaps nicely overlap the solar spectrum

Role of the d -d interaction in the antiferromagnetic phase of λ -(BEDT-STF ) 2FeCl4

Science.gov (United States)

Minamidate, Takaaki; Shindo, Hironori; Ihara, Yoshihiko; Kawamoto, Atsushi; Matsunaga, Noriaki; Nomura, Kazushige

2018-03-01

Magnetic susceptibility and proton nuclear magnetic resonance (1H-NMR ) measurements were performed for the quasi-two-dimensional π -d interacting system λ -(BEDT-STF ) 2FeCl4 at ambient pressure. Magnetic susceptibility arising from the 3 d spins of the FeCl4 anion show an anisotropy at low temperature and its temperature dependence for the external field parallel to the c axis is described as a broad peak structure at 8 K. A sharp peak in the temperature dependence of T1-1 associated with the antiferromagnetic (AF) transition is observed at TAF=16 K, together with the drastic splitting of the NMR spectrum below TAF. The relation between the static susceptibility and the splitting of the NMR shift suggests the existence of the relatively strong d -d AF interaction. These results can be explained by the model considering the AF-coupled d -spin system in the AF long-range-ordered π -spin system. We find that the AF phases in λ -type salts can be universally explained by this model.

In Situ Studies of Fe4+ Stability in β-Li3Fe2(PO4)3 Cathodes for Li Ion Batteries

DEFF Research Database (Denmark)

Christiansen, Ane Sælland; Johnsen, Rune E.; Norby, Poul

2015-01-01

In commercial Fe-based batteries the Fe2+/Fe3+ oxidation states are used, however by also utilizing the Fe4+ oxidation state, intercalation of up to two Li ions per Fe ion could be possible. In this study, we investigate whether Fe4+ can be formed and stabilized in β-Li3Fe2(PO4)3. The work includes...... of Fe4+ formation. Oxidation of the organic electrolyte is inevitable at 4.5 V but this alone cannot explain the volume change. Instead, a reversible oxygen redox process (O2− → O−) could possibly explain and charge compensate for the reversible extraction of lithium ions from β-Li3Fe2(PO4)3....... in situ synchrotron X-ray powder diffraction studies (XRPD) during charging of β-Li3Fe2(PO4)3 up to 5.0 V vs. Li/Li+. A novel capillary-based micro battery cell for in situ XRPD has been designed for this. During charge, a plateau at 4.5 V was found and a small contraction in volume was observed...

Efficient dense blur map estimation for automatic 2D-to-3D conversion

Science.gov (United States)

Vosters, L. P. J.; de Haan, G.

2012-03-01

Focus is an important depth cue for 2D-to-3D conversion of low depth-of-field images and video. However, focus can be only reliably estimated on edges. Therefore, Bea et al. [1] first proposed an optimization based approach to propagate focus to non-edge image portions, for single image focus editing. While their approach produces accurate dense blur maps, the computational complexity and memory requirements for solving the resulting sparse linear system with standard multigrid or (multilevel) preconditioning techniques, are infeasible within the stringent requirements of the consumer electronics and broadcast industry. In this paper we propose fast, efficient, low latency, line scanning based focus propagation, which mitigates the need for complex multigrid or (multilevel) preconditioning techniques. In addition we propose facial blur compensation to compensate for false shading edges that cause incorrect blur estimates in people's faces. In general shading leads to incorrect focus estimates, which may lead to unnatural 3D and visual discomfort. Since visual attention mostly tends to faces, our solution solves the most distracting errors. A subjective assessment by paired comparison on a set of challenging low-depth-of-field images shows that the proposed approach achieves equal 3D image quality as optimization based approaches, and that facial blur compensation results in a significant improvement.

Effects of Fe-Enrichment on the Equation of State and Stability of (Mg,Fe)SiO3 Perovskite and Post-Perovskite

Science.gov (United States)

Dorfman, S. M.; Holl, C. M.; Meng, Y.; Prakapenka, V.; Duffy, T. S.

2010-12-01

Fe-enrichment in the deep lower mantle has been proposed as an explanation for seismic anomalies such as large low shear velocity provinces (LLSVPs) and ultralow velocity zones (ULVZs). In order to resolve the effect of Fe on the stability and equation of state of the lower mantle’s dominant constituent, (Mg,Fe)SiO3 perovskite, we have studied Fe-rich natural orthopyroxenes, (Mg0.61Fe0.37Ca0.02)SiO3 and (Mg0.25Fe0.70Ca0.05)SiO3 (compositions determined by microprobe analysis), at lower mantle P-T conditions. Pyroxene starting materials were mixed with Au (pressure calibrant and laser absorber) and loaded with NaCl or Ne (pressure medium and thermal insulator) in a symmetric diamond anvil cell. X-ray diffraction experiments at pressures up to 122 GPa with in-situ laser heating were performed at the GSECARS (13-ID-D) and HPCAT (16-ID-B) sectors of the Advanced Photon Source. Heating samples to 2000 K produced single-phase orthorhombic GdFeO3-type perovskite at 63 GPa for the Mg# 61 composition and at 72 GPa for the Mg# 25 composition. At lower pressures (56 GPa for Mg# 61, 67 GPa for Mg# 25), heating both compositions resulted in a mixture of perovskite, SiO2 and (Mg,Fe)O. These measurements provide new constraints on the dependence of (Mg,Fe)SiO3 perovskite stability on pressure and composition. Upon further compression to 93 GPa and higher pressures with laser heating, Mg# 25 perovskite transformed to a two-phase mixture of perovskite and post-perovskite. This is consistent with previous findings that Fe substitution destabilizes (Mg,Fe)SiO3 perovskite relative to (Mg,Fe)SiO3 post-perovskite (Mao et al. 2004, Caracas and Cohen 2005). The bulk modulus at 80 GPa (K80) is ~550 GPa for both Fe-rich perovskites, comparable to values measured for MgSiO3 perovskite (Lundin et al. 2008). However, the volume of Fe-rich perovskites increases linearly with Fe-content. The (Mg0.25Fe0.70Ca0.05)SiO3 perovskite is 3% greater at 80 GPa than V80 for the Mg end

Al/Fe isomorphic substitution versus Fe{sub 2}O{sub 3} clusters formation in Fe-doped aluminosilicate nanotubes (imogolite)

Energy Technology Data Exchange (ETDEWEB)

Shafia, Ehsan [Politecnico di Torino, Department of Applied Science and Technology and INSTM Unit of Torino-Politecnico (Italy); Esposito, Serena [Università degli Studi di Cassino e del Lazio Meridionale, Department of Civil and Mechanical Engineering (Italy); Manzoli, Maela; Chiesa, Mario [Università di Torino, Dipartimento di Chimica and Centro Interdipartimentale NIS (Italy); Tiberto, Paola [Electromagnetism, I.N.Ri.M. (Italy); Barrera, Gabriele [Università di Torino, Dipartimento di Chimica and Centro Interdipartimentale NIS (Italy); Menard, Gabriel [Harvard University, Department of Chemistry and Chemical Biology (United States); Allia, Paolo, E-mail: paolo.allia@polito.it [Politecnico di Torino, Department of Applied Science and Technology and INSTM Unit of Torino-Politecnico (Italy); Freyria, Francesca S. [Massachusetts Institute of Technology, Department of Chemistry (United States); Garrone, Edoardo; Bonelli, Barbara, E-mail: barbara.bonelli@polito.it [Politecnico di Torino, Department of Applied Science and Technology and INSTM Unit of Torino-Politecnico (Italy)

2015-08-15

Textural, magnetic and spectroscopic properties are reported of Fe-doped aluminosilicate nanotubes (NTs) of the imogolite type, IMO, with nominal composition (OH){sub 3}Al{sub 2−x}Fe{sub x}O{sub 3}SiOH (x = 0, 0.025, 0.050). Samples were obtained by either direct synthesis (Fe-0.025-IMO, Fe-0.050-IMO) or post-synthesis loading (Fe-L-IMO). The Fe content was either 1.4 wt% (both Fe-0.050-IMO and Fe-L-IMO) or 0.7 wt% (Fe-0.025-IMO). Textural properties were characterized by High-Resolution Transmission Electron Microscopy, X-ray diffraction and N{sub 2} adsorption/desorption isotherms at 77 K. The presence of different iron species was studied by magnetic moment measurements and three spectroscopies: Mössbauer, UV–Vis and electron paramagnetic resonance, respectively. Fe{sup 3+}/Al{sup 3+} isomorphic substitution (IS) at octahedral sites at the external surface of NTs is the main process occurring by direct synthesis at low Fe loadings, giving rise to the formation of isolated high-spin Fe{sup 3+} sites. Higher loadings give rise, besides IS, to the formation of Fe{sub 2}O{sub 3} clusters. IS occurs up to a limit of Al/Fe atomic ratio of ca. 60 (corresponding to x = 0.032). A fraction of the magnetism related to NCs is pinned by the surface anisotropy; also, clusters are magnetically interacting with each other. Post-synthesis loading leads to a system rather close to that obtained by direct synthesis, involving both IS and cluster formations. Slightly larger clusters than with direct synthesis samples, however, are formed. The occurrence of IS indicates a facile cleavage/sealing of Al–O–Al bonds: this opens the possibility to exchange Al{sup 3+} ions in pre-formed IMO NTs, a much simpler procedure compared with direct synthesis.