scholarly journals Sub-Terahertz Computer Generated Hologram with Two Image Planes

2019 ◽  
Vol 9 (4) ◽  
pp. 659 ◽  
Author(s):  
Mateusz Surma ◽  
Izabela Ducin ◽  
Przemyslaw Zagrajek ◽  
Agnieszka Siemion

An advanced optical structure such as a synthetic hologram (also called a computer-generated hologram) is designed for sub-terahertz radiation. The detailed design process is carried out using the ping-pong method, which is based on the modified iterative Gerchberg–Saxton algorithm. The novelty lies in designing and manufacturing a single hologram structure creating two different images at two distances. The hologram area is small in relation to the wavelength used (the largest hologram dimension is equivalent to around 57 wavelengths). Thus, it consists of a small amount of coded information, but despite this fact, the reconstruction is successful. Moreover, one of the reconstructed images is larger than the hologram area. Good accordance between numerical simulations and experimental evaluation was obtained.

2014 ◽  
Vol 22 (4) ◽  
pp. 291-308
Author(s):  
Jian Huang ◽  
Yong Chen ◽  
Zhinan Zhang ◽  
Youbai Xie

2021 ◽  
Vol 41 (8) ◽  
pp. 0823017
Author(s):  
韩张华 Han Zhanghua ◽  
孙开礼 Sun Kaili ◽  
蔡阳健 Cai Yangjian

Author(s):  
Maxime Moret ◽  
Alexandre Delecourt ◽  
Hany Moustapha ◽  
Francois Garnier ◽  
Acher-Igal Abenhaim

The use of Multidisciplinary Design Optimization (MDO) techniques at the preliminary design phase (PMDO) of a gas turbine engine allows investing more effort at the pre-detailed phase in order to prevent the selection of an unsatisfactory concept early in the design process. Considering the impact of the turbine tip clearance on an engine’s efficiency, an accurate tool to predict the tip gap is a mandatory step towards the implementation of a full PMDO system for the turbine design. Tip clearance calculation is a good candidate for PMDO technique implementation considering that it implies various analyses conducted on both the rotor and stator. As a first step to the development of such tip clearance calculator satisfying PMDO principles, the present work explores the automation feasibility of the whole analysis phase of a turbine rotor preliminary design process and the potential increase in the accuracy of results and time gains. The proposed conceptual system integrates a thermal boundary conditions automated calculator and interacts with a simplified air system generator and with several conception tools based on parameterized CAD models. Great improvements were found when comparing this work’s analysis results with regular pre-detailed level tools, as they revealed to be close to the one generated by the detailed design tools used as target. Moreover, this design process revealed to be faster than a common preliminary design phase while leading to a reduction of time spent at the detailed design phase. By requiring fewer user inputs, this system decreases the risk of human errors while entirely leaving the important decisions to the designer.


1994 ◽  
Vol 33 (5) ◽  
pp. 869 ◽  
Author(s):  
Rainer G. Dorsch ◽  
Adolf W. Lohmann ◽  
Stefan Sinzinger

2016 ◽  
Vol 65 (1) ◽  
pp. 117-132 ◽  
Author(s):  
Chen Xiao-Qiang ◽  
Hao Chun-Ling ◽  
Qiu Hao ◽  
Li Min

AbstractIn this paper, a low kilo-volt-ampere rating zigzag connected autotransformer based 36-pulse rectifier system supplying vector controlled induction motor drives (VCIMD) is designed, modeled and simulated. Detailed design procedure and magnetic rating calculation of the proposed autotransformer and interphase reactor is studied. Moreover, the design process of the autotransformer is modified to make it suitable for retrofit applications. Simulation results confirm that the proposed 36-pulse rectifier system is able to suppress less than 35thharmonics in the utility line current. The influence of load variation and load character is also studied to demonstrate the performance and effectiveness of the proposed 36-pulse rectifiers. A set of power quality indices at AC mains and DC link are presented to compare the performance of 6-, 24- and 36-pulse AC-DC converters.


Author(s):  
Rong-Yuan Jou

A freezing chucker is a clamp-less mechanism of fixture for easy broken egg-shell, clay, and other ferrous/nonferrous materials. Typical structure of this mechanism includes a top plate for freezing workpieces, a body with specially designed channels for the coolant flows, and a bottom plate to fasten on the table of other machine. Just by a small amount of liquids on the top surface and by rapidly cool down to 253K, parts can be frozen stationary on the top plate surface and can conduct precision machining on it. There are four steps to design a new freeze chucker by the engineering design process: planning and clarifying the task; conceptual design; embodiment design; detailed design. Some useful tools from the Quality Function Deployment (QFD) technique and the Theory of Inventive Problem Solving (TRIZ) method are used in this design process. Eight concept designs are generated by the conceptual design work and the final design of channel with transverse ribs is selected by decision matrix technique during embodiment design and detailed design stage. This final design is evaluated by numerical modeling of the COMSOL MULTIPHYSICS 3.2 finite-element based package. Performances such as the temperature distribution of top-plate surface temperature and the lowest temperature of a freezing chucker are shown. Numerical results show the success of the innovative channel design by this inventive design process using TRIZ methodology.


Author(s):  
A. C. Ward ◽  
W. P. Seering

Abstract This paper introduces the theory underlying a computer program that takes as input a schematic of a mechanical or hydraulic power transmission system, plus specifications and a utility function, and returns catalog numbers from predefined catalogs for the optimal selection of components implementing the design. Unlike programs for designing single components or systems, this program provides the designer with a high level “language“ in which to compose new designs. It then performs much of the detailed design process. The process of “compilation”, or transformation from a high to a low level description, is based on a formalization of quantitative inferences about hierarchically organized sets of artifacts and operating conditions. This allows design compilation without the exhaustive enumeration of alternatives. The paper introduces the formalism, illustrating its use with examples. It then outlines some differences from previous work, and summarizes early tests and conclusions.


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