TY - JOUR A1 - Jeromin, Günter Erich A1 - Welsch, Volker T1 - Diketene a New Esterification Reagent in the Enzyme-Aided Synthesis of Chiral Alcohols and Chiral Acetoacetic Acid Esters JF - Tetrahedron Letters . 36 (1995), H. 37 Y1 - 1995 SN - 0040-4039 N1 - ISSN der E-Ausg.: 1359-8562 SP - 6663 EP - 6664 ER - TY - JOUR A1 - Keusgen, M. A1 - Kloock, Joachim P. A1 - Knobbe, D.-T. A1 - Jünger, M. A1 - Krest, I. A1 - Goldbach, M. A1 - Klein, W. A1 - Schöning, Michael Josef T1 - Direct determination of cyanides by potentiometric biosensors JF - Sensors and Actuators B. 103 (2004), H. 1-2 Y1 - 2004 SN - 0925-4005 SP - 380 EP - 385 ER - TY - JOUR A1 - Schüller-Ruhl, Aaron A1 - Dinstühler, Leonard A1 - Senger, Thorsten A1 - Bergfeld, Stefan A1 - Ingenhag, Christian A1 - Fleischhaker, Robert ED - Mackenzie, Jacob T1 - Direct fabrication of arbitrary phase masks in optical glass via ultra-short pulsed laser writing of refractive index modifications JF - Applied Physics B N2 - We study the possibility to fabricate an arbitrary phase mask in a one-step laser-writing process inside the volume of an optical glass substrate. We derive the phase mask from a Gerchberg–Saxton-type algorithm as an array and create each individual phase shift using a refractive index modification of variable axial length. We realize the variable axial length by superimposing refractive index modifications induced by an ultra-short pulsed laser at different focusing depth. Each single modification is created by applying 1000 pulses with 15 μJ pulse energy at 100 kHz to a fixed spot of 25 μm diameter and the focus is then shifted axially in steps of 10 μm. With several proof-of-principle examples, we show the feasibility of our method. In particular, we identify the induced refractive index change to about a value of Δn=1.5⋅10−3. We also determine our current limitations by calculating the overlap in the form of a scalar product and we discuss possible future improvements. Y1 - 2022 U6 - http://dx.doi.org/10.1007/s00340-022-07928-2 SN - 1432-0649 (Online) SN - 0946-2171 (Print) N1 - Corresponding author: Robert Fleischhaker VL - 128 IS - Article number: 208 SP - 1 EP - 11 PB - Springer CY - Berlin ER - TY - JOUR A1 - Staat, Manfred T1 - Direct FEM Limit and Shakedown Analysis with Uncertain Data N2 - The structural reliability with respect to plastic collapse or to inadaptation is formulated on the basis of the lower bound limit and shakedown theorems. A direct definition of the limit state function is achieved which permits the use of the highly effective first order reliability methods (FORM) is achieved. The theorems are implemented into a general purpose FEM program in a way capable of large-scale analysis. The limit state function and its gradient are obtained from a mathematical optimization problem. This direct approach reduces considerably the necessary knowledge of uncertain technological input data, the computing time, and the numerical error, leading to highly effective and precise reliability analyses. KW - Finite-Elemente-Methode KW - Einspielen KW - FEM KW - Einspielanalyse KW - shakedown KW - limit load KW - reliability analysis KW - FEM KW - direct method Y1 - 2000 ER - TY - JOUR A1 - Staat, Manfred A1 - Heitzer, M. A1 - Lang, H. A1 - Wirtz, K. T1 - Direct Finite Element Route for Design-by-Analysis of Pressure Components JF - International Journal of Pressure Vessels and Piping. 82 (2005), H. 1 Y1 - 2005 SN - 0308-0161 SP - 61 EP - 67 ER - TY - JOUR A1 - Staat, Manfred T1 - Direct finite element route for design-by-analysis of pressure components N2 - In the new European standard for unfired pressure vessels, EN 13445-3, there are two approaches for carrying out a Design-by-Analysis that cover both the stress categorization method (Annex C) and the direct route method (Annex B) for a check against global plastic deformation and against progressive plastic deformation. This paper presents the direct route in the language of limit and shakedown analysis. This approach leads to an optimization problem. Its solution with Finite Element Analysis is demonstrated for mechanical and thermal actions. One observation from the examples is that the so-called 3f (3Sm) criterion fails to be a reliable check against progressive plastic deformation. Precise conditions are given, which greatly restrict the applicability of the 3f criterion. KW - Einspielen KW - Plastizität KW - Deformation KW - Analytischer Zulaessigkeitsnachweis KW - Einspiel-Analyse KW - fortschreitende plastische Deformation KW - alternierend Verformbarkeit KW - Einspiel-Kriterium KW - Design-by-analysis KW - Shakedown analysis KW - Progressive plastic deformation KW - Alternating plasticity KW - Shakedown criterion Y1 - 2005 ER - TY - JOUR A1 - Prume, Klaus A1 - Tiedke, S. A1 - Schmitz, T. A1 - Roelofs, A. T1 - Direct hysteresis measurements of single nanosized ferroelectric capacitors contacted with an atomic force microscope / Tiedke, S. ; Schmitz, T. ; Prume, K. ; Roelofs, A. ; Schneller, T. ; Kall, U. ; Waser, R. ; Ganpule, C. S. ; Nagarajan, V. ; Stanishevs JF - Applied Physics Letters. 79 (2001), H. 22 Y1 - 2001 SN - 0003-6951 SP - 3678 EP - 3680 ER - TY - JOUR A1 - Hüning, Felix A1 - Backes, Andreas T1 - Direct observation of large Barkhausen jump in thin Vicalloy wires JF - IEEE Magnetics Letters Y1 - 2020 SN - 1949-307X U6 - http://dx.doi.org/10.1109/LMAG.2020.3046411 VL - 11 IS - Art. 2506504 SP - 1 EP - 4 PB - IEEE CY - New York, NY ER - TY - JOUR A1 - Tran, Ngoc Trinh A1 - Staat, Manfred T1 - Direct plastic structural design under lognormally distributed strength by chance constrained programming JF - Optimization and Engineering N2 - We propose the so-called chance constrained programming model of stochastic programming theory to analyze limit and shakedown loads of structures under random strength with a lognormal distribution. A dual chance constrained programming algorithm is developed to calculate simultaneously both the upper and lower bounds of the plastic collapse limit and the shakedown limit. The edge-based smoothed finite element method (ES-FEM) is used with three-node linear triangular elements. Y1 - 2020 U6 - http://dx.doi.org/10.1007/s11081-019-09437-2 SN - 1573-2924 VL - 21 IS - 1 SP - 131 EP - 157 PB - Springer Nature CY - Cham ER - TY - JOUR A1 - Tran, Ngoc Trinh A1 - Staat, Manfred T1 - Direct plastic structural design under random strength and random load by chance constrained programming JF - European Journal of Mechanics - A/Solids Y1 - 2021 U6 - http://dx.doi.org/10.1016/j.euromechsol.2020.104106 SN - 0997-7538 VL - 85 IS - Article 104106 PB - Elsevier CY - Amsterdam ER -