Browsing by Subject "Analytical methods"

Now showing 1 - 3 of 3

Embargo
Development of a selective wet-chemical etchant for precise 3D sculpting of silicon enabled by infrared non-linear laser modification
(Elsevier Ltd, 2025-04-17) Borrai, Mona Zolfaghari; Radfar, Behrad; Nasser, Hisham; Çolakoğlu, Tahir; Tokel, Onur; Turnalı, Ahmet; Demirtaş, Merve; Taşgın, Dilek Işık; Üstünel, Hande; Toffoli, Daniele; İlday, Fatih Ömer; Turan, Raşit; Pavlov, Ihor; Bek, Alpan
Recently-demonstrated high-quality three-dimensional (3D) subsurface laser processing inside crystalline silicon (c-Si) wafers opens a door to a wide range of novel applications in multidisciplinary research areas. Using this technique, novel maskless micro-pillars with precise control on the surface reflection and coverage are successfully fabricated by etching the laser-processed region of the c-Si wafer. To achieve this, a particular selective wet chemical etching is developed to follow subsurface laser processing of c-Si to reveal the desired 3D structures with smooth surfaces. Here, we report the development of a novel chromium-free chemical etching recipe based on copper nitrate, which yields substantially smooth surfaces at a high etch rate and selectivity on the both laserprocessed Si surface and subsurface, i.e., without significant etching of the unmodified Si. Our results show that the etch rate and surface morphology are interrelated and strongly influenced by the composition of the adopted etching solution. After an extensive compositional study performed at room temperature, we identify an etchant with a selectivity of over 1600 times for laser-modified Si with respect to unmodified Si. We also support our findings using density functional theory calculations of HF and Cu adsorption energies, indicating significant diversity on the c-Si and laser-modified surfaces.
Open Access
Motion control for realistic walking behavior using inverse kinematics
(IEEE, 2007-05) Memişoǧlu, Aydemir; Güdükbay,Uğur; Özgüç, Bülent
This study presents an interactive hierarchical motion control system for the animation of human figure locomotion. The articulated figure animation system creates movements using motion control techniques at different levels, like goal-directed motion and walking. Inverse Kinematics using Analytical Methods (IKAN) software, developed at the University of Pennsylvania, is utilized for controlling the motion of the articulated body. © 2007 IEEE.
Open Access
Performance analysis of two-level forward error correction for lostcell recovery in ATM networks
(IEEE, 1995-04) Oğuz, Nihat Cem; Ayanoğlu, E.
The major source of errors in B-ISDN/ATM systems is expected to be buffer overflow during congested conditions, resulting in ATM cell losses which degrade the quality of service. It has been shown by many authors that the performance of the end-to-end system can be made much less sensitive to cell loss by means of forward error correction. This paper discusses the use of a two-level forward error correction scheme for virtual channel and virtual path connections in ATM networks. The scheme exploits simple block coding and code interleaving simultaneously. The simple block, interleaved, and joint coding schemes are studied and analyzed by using a novel and accurate discrete-time analytical method which enables the burstiness of cell losses be captured precisely. Detailed performance calculations, which indicate that it is possible to reduce the cell loss rate by several orders of magnitude over a wide range of network load for various traffic conditions, are discussed, and compared with simulation results. The comparisons show that the method is very accurate for bursty traffic. The advantages of the three coding techniques are quantified for different traffic characteristics and scenarios © Copyright 2009 IEEE - All Rights Reserved.