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Thomae D.,Carl Zeiss GmbH | Sandfuchs O.,Hamm-Lippstadt University of Applied Sciences | Brunner R.,Carl Zeiss GmbH
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2015

The Talbot self-imaging effect of amplitude gratings is afflicted with aberrations that distort the self-image. This occurs especially if the grating period p is only a few times larger than the illumination wavelength λ. For example, for lithographic applications of the Talbot effect these aberrations lower the lateral writing resolution and should be minimized. Noponen found, however, some discrete ratios of p/λ in the interval of 2.0 < p/λ < 3 that are aberration-free. We generalize the definition of the Talbot distance to include oblique illumination and show how Noponen's discrete ratios can be shifted by it. In the second part, we look at ratios of p/λ larger than 3, so that there are more than five diffraction orders behind the grating. For this region we present a method to find ratios of p/λ with at least minimal aberrations and present some self-image examples that are of interest for lithographic purposes up to the range of p/λ ≈ 12. © 2015 Optical Society of America.


Keim M.,Mentor Graphics | Waayers T.,NXP Semiconductors | Morren R.,NXP Semiconductors | Hapke F.,Mentor Graphics | Krenz-Baath R.,Hamm-Lippstadt University of Applied Sciences
Proceedings - 16th Euromicro Conference on Digital System Design, DSD 2013 | Year: 2013

This paper focuses on an industrial application of the proposed 1687 standard to significantly improve the test development effort and quality of test patterns for mixed signal IPs of an automotive design. The P1687 standard will enable the industry to develop test patterns for IPs on the IP level without having to know how the IP will be embedded within different designs. To measure the impact of P1687, we are applying a commercial P1687 EDA tool on an industrial 65nm automotive design. The presented results underline the significant advantages of P1687 over the current IEEE Std 1149.1-based test methodology, in both, automation of test pattern development as well as reduction of test setup data volume by more than 50%. © 2013 IEEE.


Spura C.,Hamm-Lippstadt University of Applied Sciences
Forschung im Ingenieurwesen/Engineering Research | Year: 2015

Gear couplings are essential machine elements and where used in many areas of the gear and transmission technology. The significant advantages of gear couplings are the transmission of high drive power and torque in a small space, and the compensation of an existing radial and/or angular displacement. For this compensation a geometrically complicated special gearing and the knowledge of the load distribution within the teeth is essential. To calculate the load distribution, the focal factor is the tooth stiffness and its dependence on various influencing variables. The following article shows the basic principles and the present knowledge of the tooth stiffness calculation for gear couplings and shows the application of the methods for calculating the contemporary practical use in the design phase of this machine element. © 2015, Springer-Verlag Berlin Heidelberg.


Meyer J.,Hamm-Lippstadt University of Applied Sciences | Tappe F.,Hamm-Lippstadt University of Applied Sciences
Advanced Optical Materials | Year: 2015

The efficient generation of white light by phosphor-converted LEDs (pcLEDs) suffers from a trade-off between high color rendition, low correlated color temperatures, and luminous efficacy. While this is partially an inherent problem, it is also caused by the spectral efficiency of the materials used. The particular challenges for materials research lie, amongst the demanding general requirements, in finding very narrow-band or line-emitting materials: excitable with blue light, emitting in the near red. A way to design Mn(IV) activated line emitters is proposed, and methods for high-throughput combinatorial syntheses are specified. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Thomae D.,Jena University of Applied Sciences | Maass J.,Carl Zeiss GmbH | Sandfuchs O.,Hamm-Lippstadt University of Applied Sciences | Gatto A.,Carl Zeiss GmbH | Brunner R.,Jena University of Applied Sciences
Applied Optics | Year: 2014

A flexible illumination system for Talbot lithography is presented, in which the Talbot mask is illuminated by discrete but variable incidence angles. Changing the illumination angle stepwise in combination with different exposure doses for different angles offers the possibility to generate periodic continuous surface relief structures. To demonstrate the capability of this approach, two exemplary micro-optical structures were manufactured. The first example isa blazed grating with a stepsize of 1.5 μm. The second element is a specific beam splitter with parabolic-shaped grating grooves. The quality of the manufacturing process is evaluated on the basis of the optical performance of the resulting micro-optical elements. © 2014 Optical Society of America.


Sturm C.,Hamm-Lippstadt University of Applied Sciences | Strube G.,Albert Ludwigs University of Freiburg | Gouda S.,German University in Cairo
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2013

The consideration of cognitive differences between user groups in the field of human-computer interaction is still in its infancy. The present paper presents two explorative studies looking at the impact of the users' native language on their performance with different menu structures for mobile phones. Object- and verb-oriented menus with different levels of hierarchy were tested with users in Mexico and Germany. A follow-up study looked at the performance with verb- and object oriented menus by Arabic native speakers in Egypt. The results suggest that flat hierarchies are to be preferred independent from any cultural impact. While the first study did not yield a significant difference between Spanish and German native speakers using verb- and object-oriented menus, Arabic users performed significantly better with verb-oriented menus. © 2013 Springer-Verlag Berlin Heidelberg.


Sturm C.,Hamm-Lippstadt University of Applied Sciences | Amer H.,German University in Cairo
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2013

The Arab Spring has been titled as "social media revolution". While there is no doubt that Facebook and twitter contributed significantly to the course of events, its role can only be understood when put into a broader technological and historical context. Therefore, we looked at the role of technology during prior revolutions such as the French Revolution in 1789. It turns out that media technology has played an important supportive role in social and political movements throughout history. The changing characteristic, however, has always been the speed of information diffusion. Therefore, it is concluded that social media should be seen as supportive but not exclusively responsible for the events of the Arab Spring. © 2013 Springer-Verlag.


Bittmann B.,Schrodinger | Haupert F.,Hamm-Lippstadt University of Applied Sciences | Schlarb A.K.,University of Kaiserslautern
Journal of Applied Polymer Science | Year: 2012

Nanocomposites gained more and more importance in the last few years because of their improved performance over the neat polymer matrix, that is, toughness and stiffness can be enhanced simultaneously by the addition of nanoparticles. However, the dispersion of these particles in the matrix remains a big challenge. In this study, two types of TiO 2 nanoparticles were dispersed in two different epoxy resins by means of ultrasound. The particle size development in dependence on the dispersion time was investigated by dynamic light scattering for the different material systems. Furthermore, the influence of the viscosity on the sonication process' efficiency was analyzed. The resulting nanocomposites were tested for fracture and Charpy toughness. SEM images revealed that the improved fracture toughness properties are correlated to a rougher fracture surface, whose formation dissipates more energy. © 2011 Wiley Periodicals, Inc.


Shoukry L.,German University in Cairo | Sturm C.,Hamm-Lippstadt University of Applied Sciences | Galal-Edeen G.H.,American University in Cairo
2012 International Conference on E-Learning and E-Technologies in Education, ICEEE 2012 | Year: 2012

This paper discusses the causes, extent and implications of the digital language divide in technologies used by young Arabic-speaking children by the example of Egyptian preschoolers. The discussion is based on two studies: A preliminary survey examining the nature of Egyptian preschoolers' use of technology and an analytical evaluation of representative Arabic literacy developing applications available for Egyptian children compared to their English counterparts. © 2012 IEEE.


Grant
Agency: Cordis | Branch: FP7 | Program: CP | Phase: ICT-2013.3.1 | Award Amount: 4.65M | Year: 2014

Today, an average family spends annually over 50 Euros on No-Failure-Found (NFF) investigations - a known problem of an unknown origin. Tomorrow, the electronic engine control system in a car will be dying after two-three years of operation due to CMOS ageing. Actions are urgently needed!A group of European experts will unite their forces in BASTION to fight against ageing and NFF issues. The project will investigate currently unknown defects, uncertain fault coverage and unclassified field returns. A new defect universe will be assembled and faults will be classified into comprehensive classes. BASTION will study the mechanisms of ageing and improve the longevity of electronic products. Embedded instrumentation and the IEEE P1687 standard will be applied to develop an ultra-low-latency, scalable error detection and localization infrastructure as well as to integrate all heterogeneous technologies into a homogeneous system.The project will complete in three years, at only a negligible fraction of costs wasted by society on NFF annually.

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