| 1. |
- Bruzzi, M, et al.
(author)
-
Radiation-hard semiconductor detectors for SuperLHC
- 2005
-
In: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 541:1-2, s. 189-201
-
Journal article (peer-reviewed)abstract
- An option of increasing the luminosity of the Large Hadron Collider (LHC) at CERN to 1035 cm-2 s-1 has been envisaged to extend the physics reach of the machine. An efficient tracking down to a few centimetres from the interaction point will be required to exploit the physics potential of the upgraded LHC. As a consequence, the semiconductor detectors close to the interaction region will receive severe doses of fast hadron irradiation and the inner tracker detectors will need to survive fast hadron fluences of up to above 1016cm-2. The CERN-RD50 project "Development of Radiation Hard Semiconductor Devices for Very High Luminosity Colliders" has been established in 2002 to explore detector materials and technologies that will allow to operate devices up to, or beyond, this limit. The strategies followed by RD50 to enhance the radiation tolerance include the development of new or defect engineered detector materials (SiC, GaN, Czochralski and epitaxial silicon, oxygen enriched Float Zone silicon), the improvement of present detector designs and the understanding of the microscopic defects causing the degradation of the irradiated detectors. The latest advancements within the RD50 collaboration on radiation hard semiconductor detectors will be reviewed and discussed in this work.
|
|
| 2. |
|
|
| 3. |
- Dammann, R., et al.
(author)
-
Frequent promoter methylation of tumor-related genes in sporadic and men2-associated pheochromocytomas
- 2005
-
In: Experimental and clinical endocrinology & diabetes. - : Georg Thieme Verlag KG. - 0947-7349 .- 1439-3646. ; 113:1, s. 1-7
-
Journal article (peer-reviewed)abstract
- Hypermethylation of CpG island promoters is associated with transcriptional inactivation of tumor suppressor genes in neoplasia. Inactivation of p16 and Pten was related to the development of pheochromocytomas. In this report, we investigated the methylation status of the p16INK4a cell cycle inhibitor gene and other prominent tumor-related genes ( PTEN, RASSF1 A, CDH1, MSH2, MLH1, VHL, and TIMP3) in sporadic and multiple endocrine neoplasia type 2 (MEN2) pheochromocytomas by methylation-specific PCR. Hypermethylation was detected in 48 % of pheochromocytomas for RASSF1 A, 24 % for p16, 36 % for MSH2, 16 % for CDH1, and 8 % for PTEN. No VHL, MLH1, and TIMP3 methylation was observed. Interestingly, the frequency of p16 inactivation in familial tumors was higher (5 out of 12, 42 %) than in sporadic tumors (1 out of 13, 8 %; p = 0.047) and RASSF1 A inactivation was more common in the hereditary tumors (58 %) compared to the sporadic tumors (38 %). Combined methylation of RASSF1 A and p16 was found only in MEN2-related pheochromocytomas. Thus, a subset of hereditary pheochromocytomas displays preferential methylation of p16 and RASSF1 A.
|
|
| 4. |
- Funck, W. von, et al.
(author)
-
Smoke Surfaces : An Interactive Flow Visualization Technique Inspired by Real-World Flow Experiments
- 2008
-
In: IEEE Transactions on Visualization and Computer Graphics. - 1077-2626 .- 1941-0506. ; 14:6, s. 1396-1403
-
Journal article (peer-reviewed)abstract
- Smoke rendering is a standard technique for flow visualization. Most approaches are based on a volumetric, particle based, or image based representation of the smoke. This paper introduces an alternative representation of smoke structures: as semi-transparent streak surfaces. In order to make streak surface integration fast enough for interactive applications, we avoid expensive adaptive retriangulations by coupling the opacity of the triangles to their shapes. This way, the surface shows a smoke-like look even in rather turbulent areas. Furthermore, we show modifications of the approach to mimic smoke nozzles, wool tufts, and time surfaces. The technique is applied to a number of test data sets.
|
|
| 5. |
|
|
| 6. |
- Seidel, Y. E., et al.
(author)
-
Nanostructured Pt/GC model electrodes prepared by the deposition of metal-salt-loaded micelles
- 2007
-
In: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 23:10, s. 5795-5801
-
Journal article (peer-reviewed)abstract
- Novel, nanostructured, carbon-supported Pt model electrodes with homogeneously distributed Pt nanoparticles of uniform size were fabricated and analyzed with respect to their electrochemical properties. For this purpose, Pt-salt-loaded micelles were deposited on a glassy carbon substrate and subsequently exposed to an oxygen plasma and a H-2 atmosphere for removal of the polymer carriers and reduction of the Pt salt. The morphology of the resulting nanoparticles and their electrochemical/electrocatalytic properties were characterized by high-resolution scanning electron microscopy, X-ray photoelectron spectroscopy, cyclic voltammetry, and differential electrochemical mass spectrometry for CO electrooxidation. The data demonstrate that this method is generally suited to the production of nanostructured model electrodes with well-defined and independently adjustable particle size and interparticle distance distributions, which are specifically suited for quantitative studies of transport processes in electrocatalytic reactions.
|
|
| 7. |
- Seidel, Y. E., et al.
(author)
-
Stability of nanostructured Pt/glassy carbon electrodes prepared by colloidal lithography
- 2008
-
In: Journal of the Electrochemical Society. - : The Electrochemical Society. - 0013-4651 .- 1945-7111. ; 155:3, s. K50-K58
-
Journal article (peer-reviewed)abstract
- The stability of nanostructured Pt/glassy carbon (GC) model electrodes upon exposure to a realistic electrochemical/electrocatalytic reaction environment (continuous reaction, continuous electrolyte flow) was studied by microscopic techniques, X-ray photoelectron spectroscopy, and electrochemical measurements. The model electrodes consist of Pt nanostructures with well-defined sizes and regular spacing on planar GC substrates, and were fabricated using colloidal lithography techniques. Additional plasma treatments of the GC substrates prior to Pt deposition were tested to improve the stability of the resulting Pt/GC model electrodes. Both evaporation and sputter deposition were used for Pt-film fabrication. The model catalysts prepared by Pt evaporation were found to be rather unstable. The stability was significantly improved for sputter-deposited Pt films, and Pt sputter deposition on a GC substrate, pretreated first in oxygen plasma and then in Ar plasma, resulted in stable model electrodes with a fully intact layer of Pt nanostructures after the electrocatalytic experiments.
|
|
| 8. |
- Shi, K., et al.
(author)
-
Extracting Separation Surfaces of Path Line Oriented Topology in Periodic 2D Time-Dependent Vector Fields
- 2007
-
In: Journal of WSCG. - 1213-6964. ; 15:1, s. 75-82
-
Journal article (peer-reviewed)abstract
- This paper presents an approach to extracting the separation surfaces from periodic 2D time-dependent vector fields based on a recently introduced path line oriented topology. This topology is based on critical path lines which repeat the same spatial cycle per time period. Around those path lines there are areas of similar asymptotic flow behavior basins which are captured by a 2D Poincare map as a discrete dynamical system. Due to pseudo discontinuities in this map and the discrete integration scheme, separatrices between the basins can not be obtained as integral curves. Instead we choose a point-wise approach to segment the Poincare map and apply computer vision algorithms to extract the 2D separation curves. Starting from those curves we integrate separation surfaces which partition the periodic 2D time-dependent vector field into areas of similar path line behavior. We apply our approach to a number of data sets to to demonstrate its utility.
|
|
| 9. |
- Shi, K., et al.
(author)
-
Finite-Time Transport Structures of Flow Fields
- 2008
-
In: Proc. IEEE Pacific Visualization 2008. - : IEEE Computer Society. - 9781424419661 ; , s. 63-70
-
Conference paper (peer-reviewed)abstract
- Modern experimental and computational fluid mechanics are increasingly concerned with the structure nature of fluid motion. Recent research has highlighted the analysis of one transport structure which is called Lagrangian coherent structure. However, the quantity nature of the flow transport is still unclear. In this paper, we focus on the transport characteristics of physical quantities and propose an approach to visualize the finite-time transport structure of quantity advection. This is similar to an integral convolution over a scalar field along path-lines of a flow field. Applied to a well chosen set of physical quantity fields this yields structures giving insights into the dynamical processes of the underlying flow. We demonstrate our approach on a number of test data sets.
|
|
| 10. |
- Shi, K., et al.
(author)
-
Path Line Attributes - an Information Visualization Approach to Analyzing the Dynamic Behavior of 3D Time-Dependent Flow Fields
- 2009
-
In: Topology-Based Methods in Visualization II. - : Springer. ; , s. 75-88
-
Book chapter (other academic/artistic)abstract
- We describe an approach to visually analyzing the dynamic behavior of 3D time-dependent flow fields by considering the behavior of the path lines. At selected positions in the 4D space-time domain, we compute a number of local and global properties of path lines describing relevant features of them. The resulting multivariate data set is analyzed by applying state-of-the-art information visualization approaches in the sense of a set of linked views (scatter plots, parallel coordinates, etc.) with interactive brushing and focus+context visualization. The selected path lines with certain properties are integrated and visualized as colored 3D curves. This approach allows an interactive exploration of intricate 4D flow structures. We apply our method to a number of flow data sets and describe how path line attributes are used for describing characteristic features of these flows.
|
|
| 11. |
- Shi, K., et al.
(author)
-
Path Line Oriented Topology for Periodic 2D Time-Dependent Vector Fields
- 2006
-
In: Proc. Eurographics / IEEE VGTC Symposium on Visualization (EuroVis ’06). ; , s. 139-146
-
Conference paper (peer-reviewed)abstract
- This paper presents an approach to extracting a path line oriented topological segmentation for periodic 2D time-dependent vector fields. Topological methods aiming in capturing the asymptotic behavior of path lines rarely exist because path lines are usually only defined over a fixed time-interval, making statements about their asymptotic behavior impossible. For the data class of periodic vector fields, this restriction does not apply any more. Our approach detects critical path lines as well as basins from which the path lines converge to the critical ones. We demonstrate our approach on a number of test data sets.
|
|
| 12. |
- Shi, K., et al.
(author)
-
Visualizing Transport Structures of Time-Dependent Flow Fields
- 2008
-
In: IEEE Computer Graphics and Applications. - 0272-1716 .- 1558-1756. ; 28:5, s. 24-36
-
Journal article (peer-reviewed)abstract
- This article focuses on the transport characteristics of physical properties in fluids - in particular, visualizing the finite-time transport structure of property advection. Applied to a well-chosen set of property fields, the proposed approach yields structures giving insights into the underlying flow’s dynamic processes.
|
|
| 13. |
|
|
| 14. |
- Theisel, H., et al.
(author)
-
Extraction of Parallel Vector Surfaces in 3D Time-Dependent Fields and Application to Vortex Core Line Tracking
- 2005
-
In: Proc. IEEE Visualization 2005. - 0780394623 ; , s. 631-638
-
Conference paper (peer-reviewed)abstract
- We introduce an approach to tracking vortex core lines in time-dependent 3D flow fields which are defined by the parallel vectors approach. They build surface structures in the 4D space-time domain. To extract them, we introduce two 4D vector fields which act as feature flow fields, i.e. their integration gives the vortex core structures. As part of this approach, we extract and classify local bifurcations of vortex core lines in space-time. Based on a 4D stream surface integration, we provide an algorithm to extract the complete vortex core structure. We apply our technique to a number of test data sets.
|
|
| 15. |
- Theisel, H., et al.
(author)
-
On the Applicability of Topological Methods for Complex Flow Data
- 2007
-
In: Topology-based Methods in Visualization. - : Springer. ; , s. 105-120
-
Book chapter (other academic/artistic)abstract
- In this paper we study the applicability of topological methods for creating expressive, feature revealing visualizations of 3D vector fields. 3D vector fields can become very complex by having a high number of critical points and separatrices. Moreover, they may have a very sparse topology due to a small number of critical points or their total absence. We show that classical topological methods based on the extraction of separation surfaces are poorly suited for creating expressive visualizations of topologically complex fields. We show this fact by pointing out that the number of sectors of different flow behavior grows quadratically with the number of critical points – contrary to 2D vector fields. Although this limits the applicability of topological methods to a certain degree, we demonstrate the extensibility of this limit by using further simplifying methods like saddle connectors. For 3D vector fields with a very sparse topology, topological visualizations may fail to reveal the features inherent to the field. We show how to overcome this problem for a certain class of flow fields by removing the ambient part of the flow.
|
|
| 16. |
- Theisel, H., et al.
(author)
-
Topological Methods for 2D Time-Dependent Vector Fields Based on Stream Lines and Path Lines
- 2005
-
In: IEEE Transactions on Visualization and Computer Graphics. - : IEEE Computer Society. - 1077-2626 .- 1941-0506. ; 11:4, s. 383-394
-
Journal article (peer-reviewed)abstract
- This paper describes approaches to topologically segmenting 2D time-dependent vector fields. For this class of vector fields, two important classes of lines exist: stream lines and path lines. Because of this, two segmentations are possible: either concerning the behavior of stream lines, or of path lines. While topological features based on stream lines are well established, we introduce path line oriented topology as a new visualization approach in this paper. As a contribution to stream line oriented topology we introduce new methods to detect global bifurcations like saddle connections and cyclic fold bifurcations as well as a method to tracking all isolated closed stream lines. To get the path line oriented topology we segment the vector field into areas of attracting, repelling and saddle-like behavior of the path lines. We compare both kinds of topologies and apply them to a number of test data sets.
|
|
| 17. |
- Weinkauf, Tino, 1974-, et al.
(author)
-
A Unified Feature Extraction Architecture
- 2007
-
In: Active Flow Control. - : Springer. ; , s. 119-133
-
Book chapter (other academic/artistic)abstract
- We present a unified feature extraction architecture consisting of only three core algorithms that allows to extract and track a rich variety of geometrically defined, local and global features evolving in scalar and vector fields. The architecture builds upon the concepts of Feature Flow Fields and Connectors, which can be implemented using the three core algorithms finding zeros, integrating and intersecting stream objects. We apply our methods to extract and track the topology and vortex core lines both in steady and unsteady flow fields.
|
|
| 18. |
- Weinkauf, Tino, 1974-, et al.
(author)
-
Extracting Higher Order Critical Points and Topological Simplification of 3D Vector Fields
- 2005
-
In: Proc. IEEE Visualization 2005. ; , s. 559-566
-
Conference paper (peer-reviewed)abstract
- This paper presents an approach to extracting and classifying higher order critical points of 3D vector fields. To do so, we place a closed convex surface s around the area of interest. Then we show that the complete 3D classification of a critical point into areas of similar flow behavior is equivalent to extracting the topological skeleton of an appropriate 2D vector field on s, if each critical point is equipped with an additional Bit of information. Out of this skeleton, we create an icon which replaces the complete topological structure inside s for the visualization. We apply our method to find a simplified visual representation of clusters of critical points, leading to expressive visualizations of topologically complex 3D vector fields.
|
|
| 19. |
- Weinkauf, Tino, 1974-, et al.
(author)
-
Feature Flow Fields in Out-of-Core Settings
- 2007
-
In: Topology-based Methods in Visualization. - : Springer. ; , s. 51-64
-
Book chapter (other academic/artistic)abstract
- Feature Flow Fields (FFF) are an approach to tracking features in a time-dependent vector field v. The main idea is to introduce an appropriate vector field f in space-time, such that a feature tracking in v corresponds to a stream line integration in f. The original approach of feature tracking using FFF requested that the complete vector field v is kept in main memory. Especially for 3D vector fields this may be a serious restriction, since the size of time-dependent vector fields can exceed the main memory of even high-end workstations. We present a modification of the FFF-based tracking approach which works in an out-of-core manner. For an important subclass of all possible FFF-based tracking algorithms we ensure to analyze the data in one sweep while holding only two consecutive time steps in main memory at once. Similar to the original approach, the new modification guarantees the complete feature skeleton to be found. We apply the approach to tracking of critical points in 2D and 3D time-dependent vector fields.
|
|
| 20. |
- Weinkauf, Tino, 1974-, et al.
(author)
-
Topological Construction and Visualization of Higher Order 3D Vector Fields
- 2006
-
In: Computer graphics forum (Print). - : Wiley. - 0167-7055 .- 1467-8659. ; 23:3, s. 469-478
-
Journal article (peer-reviewed)abstract
- We present the first algorithm for constructing 3D vector fields based on their topological skeleton. The skeleton itself is modeled by interactively moving a number of control polygons. Then a piecewise linear vector field is automatically constructed which has the same topological skeleton as modeled before. This approach is based on a complete segmentation of the areas around critical points into sectors of different flow behavior. Based on this, we present the first approach to visualizing higher order critical points of 3D vector fields.
|
|
| 21. |
- Weinkauf, Tino, 1974-, et al.
(author)
-
Topological Structures in Two-Parameter-Dependent 2D Vector Fields
- 2006
-
In: Computer graphics forum (Print). - : Wiley. - 0167-7055 .- 1467-8659. ; 25:3, s. 607-616
-
Journal article (peer-reviewed)abstract
- In this paper we extract and visualize the topological skeleton of two-parameter-dependent vector fields. This kind of vector data depends on two parameter dimensions, for instance physical time and a scale parameter. We show that two important classes of local bifurcations – fold and Hopf bifurcations – build line structures for which we present an approach to extract them. Furthermore we show that new kinds of structurally stable local bifurcations exist for this data, namely fold-fold and Hopf-fold bifurcations. We present a complete classification of them. We apply our topological extraction method to analyze a number of two-parameter-dependent vector fields with different physical interpretations of the two additional dimensions.
|
|
